NEWS
author wenzelm
Sun, 19 Jul 2009 19:24:04 +0200
changeset 32077 11f8ee55662d
parent 31997 de0d280c31a7
child 32079 5dc52b199815
permissions -rw-r--r--
parallel_proofs: more fine-grained control with optional parallel checking of nested Isar proofs;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Discontinued old form of "escaped symbols" such as \\<forall>.  Only
    10 one backslash should be used, even in ML sources.
    11 
    12 
    13 *** Pure ***
    14 
    15 * On instantiation of classes, remaining undefined class parameters
    16 are formally declared.  INCOMPATIBILITY.
    17 
    18 
    19 *** HOL ***
    20 
    21 * Code generator attributes follow the usual underscore convention:
    22     code_unfold     replaces    code unfold
    23     code_post       replaces    code post
    24     etc.
    25   INCOMPATIBILITY.
    26 
    27 * New quickcheck implementation using new code generator.
    28 
    29 * New type class boolean_algebra.
    30 
    31 * Class semiring_div requires superclass no_zero_divisors and proof of
    32 div_mult_mult1; theorems div_mult_mult1, div_mult_mult2,
    33 div_mult_mult1_if, div_mult_mult1 and div_mult_mult2 have been
    34 generalized to class semiring_div, subsuming former theorems
    35 zdiv_zmult_zmult1, zdiv_zmult_zmult1_if, zdiv_zmult_zmult1 and
    36 zdiv_zmult_zmult2.  div_mult_mult1 is now [simp] by default.
    37 INCOMPATIBILITY.
    38 
    39 * Power operations on relations and functions are now one dedicate
    40 constant compow with infix syntax "^^".  Power operations on
    41 multiplicative monoids retains syntax "^" and is now defined generic
    42 in class power.  INCOMPATIBILITY.
    43 
    44 * ML antiquotation @{code_datatype} inserts definition of a datatype
    45 generated by the code generator; see Predicate.thy for an example.
    46 
    47 * New method "linarith" invokes existing linear arithmetic decision
    48 procedure only.
    49 
    50 * Implementation of quickcheck using generic code generator; default
    51 generators are provided for all suitable HOL types, records and
    52 datatypes.
    53 
    54 * Constants Set.Pow and Set.image now with authentic syntax;
    55 object-logic definitions Set.Pow_def and Set.image_def.
    56 INCOMPATIBILITY.
    57 
    58 * Renamed theorems:
    59 Suc_eq_add_numeral_1 -> Suc_eq_plus1
    60 Suc_eq_add_numeral_1_left -> Suc_eq_plus1_left
    61 Suc_plus1 -> Suc_eq_plus1
    62 
    63 * New sledgehammer option "Full Types" in Proof General settings menu.
    64 Causes full type information to be output to the ATPs.  This slows
    65 ATPs down considerably but eliminates a source of unsound "proofs"
    66 that fail later.
    67 
    68 * Discontinued ancient tradition to suffix certain ML module names
    69 with "_package", e.g.:
    70 
    71     DatatypePackage ~> Datatype
    72     InductivePackage ~> Inductive
    73 
    74     etc.
    75 
    76 INCOMPATIBILITY.
    77 
    78 * NewNumberTheory: Jeremy Avigad's new version of part of
    79 NumberTheory.  If possible, use NewNumberTheory, not NumberTheory.
    80 
    81 * Simplified interfaces of datatype module.  INCOMPATIBILITY.
    82 
    83 * Abbreviation "arbitrary" of "undefined" has disappeared; use
    84 "undefined" directly.  INCOMPATIBILITY.
    85 
    86 * New evaluator "approximate" approximates an real valued term using
    87 the same method as the approximation method.
    88 
    89 * Method "approximate" supports now arithmetic expressions as
    90 boundaries of intervals and implements interval splitting and Taylor
    91 series expansion.
    92 
    93 * Changed DERIV_intros to a dynamic fact (via Named_Thms).  Each of
    94 the theorems in DERIV_intros assumes composition with an additional
    95 function and matches a variable to the derivative, which has to be
    96 solved by the simplifier.  Hence (auto intro!: DERIV_intros) computes
    97 the derivative of most elementary terms.
    98 
    99 * Maclauren.DERIV_tac and Maclauren.deriv_tac was removed, they are
   100 replaced by: (auto intro!: DERIV_intros).  INCOMPATIBILITY.
   101 
   102 
   103 *** ML ***
   104 
   105 * Renamed functor TableFun to Table, and GraphFun to Graph.  (Since
   106 functors have their own ML name space there is no point to mark them
   107 separately.)  Minor INCOMPATIBILITY.
   108 
   109 * Renamed NamedThmsFun to Named_Thms.  INCOMPATIBILITY.
   110 
   111 * Eliminated old Attrib.add_attributes, Method.add_methods and related
   112 cominators for "args".  INCOMPATIBILITY, need to use simplified
   113 Attrib/Method.setup introduced in Isabelle2009.
   114 
   115 
   116 *** System ***
   117 
   118 * Discontinued support for Poly/ML 4.x versions.
   119 
   120 * Removed "compress" option from isabelle-process and isabelle usedir;
   121 this is always enabled.
   122 
   123 * More fine-grained control of proof parallelism, cf.
   124 Goal.parallel_proofs in ML and usedir option -q LEVEL.
   125 
   126 
   127 
   128 New in Isabelle2009 (April 2009)
   129 --------------------------------
   130 
   131 *** General ***
   132 
   133 * Simplified main Isabelle executables, with less surprises on
   134 case-insensitive file-systems (such as Mac OS).
   135 
   136   - The main Isabelle tool wrapper is now called "isabelle" instead of
   137     "isatool."
   138 
   139   - The former "isabelle" alias for "isabelle-process" has been
   140     removed (should rarely occur to regular users).
   141 
   142   - The former "isabelle-interface" and its alias "Isabelle" have been
   143     removed (interfaces are now regular Isabelle tools).
   144 
   145 Within scripts and make files, the Isabelle environment variables
   146 ISABELLE_TOOL and ISABELLE_PROCESS replace old ISATOOL and ISABELLE,
   147 respectively.  (The latter are still available as legacy feature.)
   148 
   149 The old isabelle-interface wrapper could react in confusing ways if
   150 the interface was uninstalled or changed otherwise.  Individual
   151 interface tool configuration is now more explicit, see also the
   152 Isabelle system manual.  In particular, Proof General is now available
   153 via "isabelle emacs".
   154 
   155 INCOMPATIBILITY, need to adapt derivative scripts.  Users may need to
   156 purge installed copies of Isabelle executables and re-run "isabelle
   157 install -p ...", or use symlinks.
   158 
   159 * The default for ISABELLE_HOME_USER is now ~/.isabelle instead of the
   160 old ~/isabelle, which was slightly non-standard and apt to cause
   161 surprises on case-insensitive file-systems (such as Mac OS).
   162 
   163 INCOMPATIBILITY, need to move existing ~/isabelle/etc,
   164 ~/isabelle/heaps, ~/isabelle/browser_info to the new place.  Special
   165 care is required when using older releases of Isabelle.  Note that
   166 ISABELLE_HOME_USER can be changed in Isabelle/etc/settings of any
   167 Isabelle distribution, in order to use the new ~/.isabelle uniformly.
   168 
   169 * Proofs of fully specified statements are run in parallel on
   170 multi-core systems.  A speedup factor of 2.5 to 3.2 can be expected on
   171 a regular 4-core machine, if the initial heap space is made reasonably
   172 large (cf. Poly/ML option -H).  (Requires Poly/ML 5.2.1 or later.)
   173 
   174 * The main reference manuals ("isar-ref", "implementation", and
   175 "system") have been updated and extended.  Formally checked references
   176 as hyperlinks are now available uniformly.
   177 
   178 
   179 *** Pure ***
   180 
   181 * Complete re-implementation of locales.  INCOMPATIBILITY in several
   182 respects.  The most important changes are listed below.  See the
   183 Tutorial on Locales ("locales" manual) for details.
   184 
   185 - In locale expressions, instantiation replaces renaming.  Parameters
   186 must be declared in a for clause.  To aid compatibility with previous
   187 parameter inheritance, in locale declarations, parameters that are not
   188 'touched' (instantiation position "_" or omitted) are implicitly added
   189 with their syntax at the beginning of the for clause.
   190 
   191 - Syntax from abbreviations and definitions in locales is available in
   192 locale expressions and context elements.  The latter is particularly
   193 useful in locale declarations.
   194 
   195 - More flexible mechanisms to qualify names generated by locale
   196 expressions.  Qualifiers (prefixes) may be specified in locale
   197 expressions, and can be marked as mandatory (syntax: "name!:") or
   198 optional (syntax "name?:").  The default depends for plain "name:"
   199 depends on the situation where a locale expression is used: in
   200 commands 'locale' and 'sublocale' prefixes are optional, in
   201 'interpretation' and 'interpret' prefixes are mandatory.  The old
   202 implicit qualifiers derived from the parameter names of a locale are
   203 no longer generated.
   204 
   205 - Command "sublocale l < e" replaces "interpretation l < e".  The
   206 instantiation clause in "interpretation" and "interpret" (square
   207 brackets) is no longer available.  Use locale expressions.
   208 
   209 - When converting proof scripts, mandatory qualifiers in
   210 'interpretation' and 'interpret' should be retained by default, even
   211 if this is an INCOMPATIBILITY compared to former behavior.  In the
   212 worst case, use the "name?:" form for non-mandatory ones.  Qualifiers
   213 in locale expressions range over a single locale instance only.
   214 
   215 - Dropped locale element "includes".  This is a major INCOMPATIBILITY.
   216 In existing theorem specifications replace the includes element by the
   217 respective context elements of the included locale, omitting those
   218 that are already present in the theorem specification.  Multiple
   219 assume elements of a locale should be replaced by a single one
   220 involving the locale predicate.  In the proof body, declarations (most
   221 notably theorems) may be regained by interpreting the respective
   222 locales in the proof context as required (command "interpret").
   223 
   224 If using "includes" in replacement of a target solely because the
   225 parameter types in the theorem are not as general as in the target,
   226 consider declaring a new locale with additional type constraints on
   227 the parameters (context element "constrains").
   228 
   229 - Discontinued "locale (open)".  INCOMPATIBILITY.
   230 
   231 - Locale interpretation commands no longer attempt to simplify goal.
   232 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
   233 methods intro_locales and unfold_locales to clarify.
   234 
   235 - Locale interpretation commands no longer accept interpretation
   236 attributes.  INCOMPATIBILITY.
   237 
   238 * Class declaration: so-called "base sort" must not be given in import
   239 list any longer, but is inferred from the specification.  Particularly
   240 in HOL, write
   241 
   242     class foo = ...
   243 
   244 instead of
   245 
   246     class foo = type + ...
   247 
   248 * Class target: global versions of theorems stemming do not carry a
   249 parameter prefix any longer.  INCOMPATIBILITY.
   250 
   251 * Class 'instance' command no longer accepts attached definitions.
   252 INCOMPATIBILITY, use proper 'instantiation' target instead.
   253 
   254 * Recovered hiding of consts, which was accidentally broken in
   255 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
   256 makes c inaccessible; consider using ``hide (open) const c'' instead.
   257 
   258 * Slightly more coherent Pure syntax, with updated documentation in
   259 isar-ref manual.  Removed locales meta_term_syntax and
   260 meta_conjunction_syntax: TERM and &&& (formerly &&) are now permanent,
   261 INCOMPATIBILITY in rare situations.  Note that &&& should not be used
   262 directly in regular applications.
   263 
   264 * There is a new syntactic category "float_const" for signed decimal
   265 fractions (e.g. 123.45 or -123.45).
   266 
   267 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
   268 interface with 'setup' command instead.
   269 
   270 * Command 'local_setup' is similar to 'setup', but operates on a local
   271 theory context.
   272 
   273 * The 'axiomatization' command now only works within a global theory
   274 context.  INCOMPATIBILITY.
   275 
   276 * Goal-directed proof now enforces strict proof irrelevance wrt. sort
   277 hypotheses.  Sorts required in the course of reasoning need to be
   278 covered by the constraints in the initial statement, completed by the
   279 type instance information of the background theory.  Non-trivial sort
   280 hypotheses, which rarely occur in practice, may be specified via
   281 vacuous propositions of the form SORT_CONSTRAINT('a::c).  For example:
   282 
   283   lemma assumes "SORT_CONSTRAINT('a::empty)" shows False ...
   284 
   285 The result contains an implicit sort hypotheses as before --
   286 SORT_CONSTRAINT premises are eliminated as part of the canonical rule
   287 normalization.
   288 
   289 * Generalized Isar history, with support for linear undo, direct state
   290 addressing etc.
   291 
   292 * Changed defaults for unify configuration options:
   293 
   294   unify_trace_bound = 50 (formerly 25)
   295   unify_search_bound = 60 (formerly 30)
   296 
   297 * Different bookkeeping for code equations (INCOMPATIBILITY):
   298 
   299   a) On theory merge, the last set of code equations for a particular
   300      constant is taken (in accordance with the policy applied by other
   301      parts of the code generator framework).
   302 
   303   b) Code equations stemming from explicit declarations (e.g. code
   304      attribute) gain priority over default code equations stemming
   305      from definition, primrec, fun etc.
   306 
   307 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
   308 
   309 * Unified theorem tables for both code generators.  Thus [code
   310 func] has disappeared and only [code] remains.  INCOMPATIBILITY.
   311 
   312 * Command 'find_consts' searches for constants based on type and name
   313 patterns, e.g.
   314 
   315     find_consts "_ => bool"
   316 
   317 By default, matching is against subtypes, but it may be restricted to
   318 the whole type.  Searching by name is possible.  Multiple queries are
   319 conjunctive and queries may be negated by prefixing them with a
   320 hyphen:
   321 
   322     find_consts strict: "_ => bool" name: "Int" -"int => int"
   323 
   324 * New 'find_theorems' criterion "solves" matches theorems that
   325 directly solve the current goal (modulo higher-order unification).
   326 
   327 * Auto solve feature for main theorem statements: whenever a new goal
   328 is stated, "find_theorems solves" is called; any theorems that could
   329 solve the lemma directly are listed as part of the goal state.
   330 Cf. associated options in Proof General Isabelle settings menu,
   331 enabled by default, with reasonable timeout for pathological cases of
   332 higher-order unification.
   333 
   334 
   335 *** Document preparation ***
   336 
   337 * Antiquotation @{lemma} now imitates a regular terminal proof,
   338 demanding keyword 'by' and supporting the full method expression
   339 syntax just like the Isar command 'by'.
   340 
   341 
   342 *** HOL ***
   343 
   344 * Integrated main parts of former image HOL-Complex with HOL.  Entry
   345 points Main and Complex_Main remain as before.
   346 
   347 * Logic image HOL-Plain provides a minimal HOL with the most important
   348 tools available (inductive, datatype, primrec, ...).  This facilitates
   349 experimentation and tool development.  Note that user applications
   350 (and library theories) should never refer to anything below theory
   351 Main, as before.
   352 
   353 * Logic image HOL-Main stops at theory Main, and thus facilitates
   354 experimentation due to shorter build times.
   355 
   356 * Logic image HOL-NSA contains theories of nonstandard analysis which
   357 were previously part of former HOL-Complex.  Entry point Hyperreal
   358 remains valid, but theories formerly using Complex_Main should now use
   359 new entry point Hypercomplex.
   360 
   361 * Generic ATP manager for Sledgehammer, based on ML threads instead of
   362 Posix processes.  Avoids potentially expensive forking of the ML
   363 process.  New thread-based implementation also works on non-Unix
   364 platforms (Cygwin).  Provers are no longer hardwired, but defined
   365 within the theory via plain ML wrapper functions.  Basic Sledgehammer
   366 commands are covered in the isar-ref manual.
   367 
   368 * Wrapper scripts for remote SystemOnTPTP service allows to use
   369 sledgehammer without local ATP installation (Vampire etc.). Other
   370 provers may be included via suitable ML wrappers, see also
   371 src/HOL/ATP_Linkup.thy.
   372 
   373 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   374 menu.
   375 
   376 * The metis method no longer fails because the theorem is too trivial
   377 (contains the empty clause).
   378 
   379 * The metis method now fails in the usual manner, rather than raising
   380 an exception, if it determines that it cannot prove the theorem.
   381 
   382 * Method "coherent" implements a prover for coherent logic (see also
   383 src/Tools/coherent.ML).
   384 
   385 * Constants "undefined" and "default" replace "arbitrary".  Usually
   386 "undefined" is the right choice to replace "arbitrary", though
   387 logically there is no difference.  INCOMPATIBILITY.
   388 
   389 * Command "value" now integrates different evaluation mechanisms.  The
   390 result of the first successful evaluation mechanism is printed.  In
   391 square brackets a particular named evaluation mechanisms may be
   392 specified (currently, [SML], [code] or [nbe]).  See further
   393 src/HOL/ex/Eval_Examples.thy.
   394 
   395 * Normalization by evaluation now allows non-leftlinear equations.
   396 Declare with attribute [code nbe].
   397 
   398 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   399 as the structured Isar versions "cases" and "induct", cf. the
   400 corresponding "cases" and "induct" attributes.  Mutual induction rules
   401 are now presented as a list of individual projections
   402 (e.g. foo_bar.inducts for types foo and bar); the old format with
   403 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   404 rare situations a different rule is selected --- notably nested tuple
   405 elimination instead of former prod.exhaust: use explicit (case_tac t
   406 rule: prod.exhaust) here.
   407 
   408 * Attributes "cases", "induct", "coinduct" support "del" option.
   409 
   410 * Removed fact "case_split_thm", which duplicates "case_split".
   411 
   412 * The option datatype has been moved to a new theory Option.  Renamed
   413 option_map to Option.map, and o2s to Option.set, INCOMPATIBILITY.
   414 
   415 * New predicate "strict_mono" classifies strict functions on partial
   416 orders.  With strict functions on linear orders, reasoning about
   417 (in)equalities is facilitated by theorems "strict_mono_eq",
   418 "strict_mono_less_eq" and "strict_mono_less".
   419 
   420 * Some set operations are now proper qualified constants with
   421 authentic syntax.  INCOMPATIBILITY:
   422 
   423     op Int ~>   Set.Int
   424     op Un ~>    Set.Un
   425     INTER ~>    Set.INTER
   426     UNION ~>    Set.UNION
   427     Inter ~>    Set.Inter
   428     Union ~>    Set.Union
   429     {} ~>       Set.empty
   430     UNIV ~>     Set.UNIV
   431 
   432 * Class complete_lattice with operations Inf, Sup, INFI, SUPR now in
   433 theory Set.
   434 
   435 * Auxiliary class "itself" has disappeared -- classes without any
   436 parameter are treated as expected by the 'class' command.
   437 
   438 * Leibnitz's Series for Pi and the arcus tangens and logarithm series.
   439 
   440 * Common decision procedures (Cooper, MIR, Ferrack, Approximation,
   441 Dense_Linear_Order) are now in directory HOL/Decision_Procs.
   442 
   443 * Theory src/HOL/Decision_Procs/Approximation provides the new proof
   444 method "approximation".  It proves formulas on real values by using
   445 interval arithmetic.  In the formulas are also the transcendental
   446 functions sin, cos, tan, atan, ln, exp and the constant pi are
   447 allowed. For examples see
   448 src/HOL/Descision_Procs/ex/Approximation_Ex.thy.
   449 
   450 * Theory "Reflection" now resides in HOL/Library.
   451 
   452 * Entry point to Word library now simply named "Word".
   453 INCOMPATIBILITY.
   454 
   455 * Made source layout more coherent with logical distribution
   456 structure:
   457 
   458     src/HOL/Library/RType.thy ~> src/HOL/Typerep.thy
   459     src/HOL/Library/Code_Message.thy ~> src/HOL/
   460     src/HOL/Library/GCD.thy ~> src/HOL/
   461     src/HOL/Library/Order_Relation.thy ~> src/HOL/
   462     src/HOL/Library/Parity.thy ~> src/HOL/
   463     src/HOL/Library/Univ_Poly.thy ~> src/HOL/
   464     src/HOL/Real/ContNotDenum.thy ~> src/HOL/Library/
   465     src/HOL/Real/Lubs.thy ~> src/HOL/
   466     src/HOL/Real/PReal.thy ~> src/HOL/
   467     src/HOL/Real/Rational.thy ~> src/HOL/
   468     src/HOL/Real/RComplete.thy ~> src/HOL/
   469     src/HOL/Real/RealDef.thy ~> src/HOL/
   470     src/HOL/Real/RealPow.thy ~> src/HOL/
   471     src/HOL/Real/Real.thy ~> src/HOL/
   472     src/HOL/Complex/Complex_Main.thy ~> src/HOL/
   473     src/HOL/Complex/Complex.thy ~> src/HOL/
   474     src/HOL/Complex/FrechetDeriv.thy ~> src/HOL/Library/
   475     src/HOL/Complex/Fundamental_Theorem_Algebra.thy ~> src/HOL/Library/
   476     src/HOL/Hyperreal/Deriv.thy ~> src/HOL/
   477     src/HOL/Hyperreal/Fact.thy ~> src/HOL/
   478     src/HOL/Hyperreal/Integration.thy ~> src/HOL/
   479     src/HOL/Hyperreal/Lim.thy ~> src/HOL/
   480     src/HOL/Hyperreal/Ln.thy ~> src/HOL/
   481     src/HOL/Hyperreal/Log.thy ~> src/HOL/
   482     src/HOL/Hyperreal/MacLaurin.thy ~> src/HOL/
   483     src/HOL/Hyperreal/NthRoot.thy ~> src/HOL/
   484     src/HOL/Hyperreal/Series.thy ~> src/HOL/
   485     src/HOL/Hyperreal/SEQ.thy ~> src/HOL/
   486     src/HOL/Hyperreal/Taylor.thy ~> src/HOL/
   487     src/HOL/Hyperreal/Transcendental.thy ~> src/HOL/
   488     src/HOL/Real/Float ~> src/HOL/Library/
   489     src/HOL/Real/HahnBanach ~> src/HOL/HahnBanach
   490     src/HOL/Real/RealVector.thy ~> src/HOL/
   491 
   492     src/HOL/arith_data.ML ~> src/HOL/Tools
   493     src/HOL/hologic.ML ~> src/HOL/Tools
   494     src/HOL/simpdata.ML ~> src/HOL/Tools
   495     src/HOL/int_arith1.ML ~> src/HOL/Tools/int_arith.ML
   496     src/HOL/int_factor_simprocs.ML ~> src/HOL/Tools
   497     src/HOL/nat_simprocs.ML ~> src/HOL/Tools
   498     src/HOL/Real/float_arith.ML ~> src/HOL/Tools
   499     src/HOL/Real/float_syntax.ML ~> src/HOL/Tools
   500     src/HOL/Real/rat_arith.ML ~> src/HOL/Tools
   501     src/HOL/Real/real_arith.ML ~> src/HOL/Tools
   502 
   503     src/HOL/Library/Array.thy ~> src/HOL/Imperative_HOL
   504     src/HOL/Library/Heap_Monad.thy ~> src/HOL/Imperative_HOL
   505     src/HOL/Library/Heap.thy ~> src/HOL/Imperative_HOL
   506     src/HOL/Library/Imperative_HOL.thy ~> src/HOL/Imperative_HOL
   507     src/HOL/Library/Ref.thy ~> src/HOL/Imperative_HOL
   508     src/HOL/Library/Relational.thy ~> src/HOL/Imperative_HOL
   509 
   510 * If methods "eval" and "evaluation" encounter a structured proof
   511 state with !!/==>, only the conclusion is evaluated to True (if
   512 possible), avoiding strange error messages.
   513 
   514 * Method "sizechange" automates termination proofs using (a
   515 modification of) the size-change principle.  Requires SAT solver.  See
   516 src/HOL/ex/Termination.thy for examples.
   517 
   518 * Simplifier: simproc for let expressions now unfolds if bound
   519 variable occurs at most once in let expression body.  INCOMPATIBILITY.
   520 
   521 * Method "arith": Linear arithmetic now ignores all inequalities when
   522 fast_arith_neq_limit is exceeded, instead of giving up entirely.
   523 
   524 * New attribute "arith" for facts that should always be used
   525 automatically by arithmetic. It is intended to be used locally in
   526 proofs, e.g.
   527 
   528   assumes [arith]: "x > 0"
   529 
   530 Global usage is discouraged because of possible performance impact.
   531 
   532 * New classes "top" and "bot" with corresponding operations "top" and
   533 "bot" in theory Orderings; instantiation of class "complete_lattice"
   534 requires instantiation of classes "top" and "bot".  INCOMPATIBILITY.
   535 
   536 * Changed definition lemma "less_fun_def" in order to provide an
   537 instance for preorders on functions; use lemma "less_le" instead.
   538 INCOMPATIBILITY.
   539 
   540 * Theory Orderings: class "wellorder" moved here, with explicit
   541 induction rule "less_induct" as assumption.  For instantiation of
   542 "wellorder" by means of predicate "wf", use rule wf_wellorderI.
   543 INCOMPATIBILITY.
   544 
   545 * Theory Orderings: added class "preorder" as superclass of "order".
   546 INCOMPATIBILITY: Instantiation proofs for order, linorder
   547 etc. slightly changed.  Some theorems named order_class.* now named
   548 preorder_class.*.
   549 
   550 * Theory Relation: renamed "refl" to "refl_on", "reflexive" to "refl,
   551 "diag" to "Id_on".
   552 
   553 * Theory Finite_Set: added a new fold combinator of type
   554 
   555   ('a => 'b => 'b) => 'b => 'a set => 'b
   556 
   557 Occasionally this is more convenient than the old fold combinator
   558 which is now defined in terms of the new one and renamed to
   559 fold_image.
   560 
   561 * Theories Ring_and_Field and OrderedGroup: The lemmas "group_simps"
   562 and "ring_simps" have been replaced by "algebra_simps" (which can be
   563 extended with further lemmas!).  At the moment both still exist but
   564 the former will disappear at some point.
   565 
   566 * Theory Power: Lemma power_Suc is now declared as a simp rule in
   567 class recpower.  Type-specific simp rules for various recpower types
   568 have been removed.  INCOMPATIBILITY, rename old lemmas as follows:
   569 
   570 rat_power_0    -> power_0
   571 rat_power_Suc  -> power_Suc
   572 realpow_0      -> power_0
   573 realpow_Suc    -> power_Suc
   574 complexpow_0   -> power_0
   575 complexpow_Suc -> power_Suc
   576 power_poly_0   -> power_0
   577 power_poly_Suc -> power_Suc
   578 
   579 * Theories Ring_and_Field and Divides: Definition of "op dvd" has been
   580 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
   581 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
   582 of lemmas from Divides has been generalized from nat to class
   583 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
   584 renames resulting from duplicate elimination:
   585 
   586     dvd_def_mod ~>          dvd_eq_mod_eq_0
   587     zero_dvd_iff ~>         dvd_0_left_iff
   588     dvd_0 ~>                dvd_0_right
   589     DIVISION_BY_ZERO_DIV ~> div_by_0
   590     DIVISION_BY_ZERO_MOD ~> mod_by_0
   591     mult_div ~>             div_mult_self2_is_id
   592     mult_mod ~>             mod_mult_self2_is_0
   593 
   594 * Theory IntDiv: removed many lemmas that are instances of class-based
   595 generalizations (from Divides and Ring_and_Field).  INCOMPATIBILITY,
   596 rename old lemmas as follows:
   597 
   598 dvd_diff               -> nat_dvd_diff
   599 dvd_zminus_iff         -> dvd_minus_iff
   600 mod_add1_eq            -> mod_add_eq
   601 mod_mult1_eq           -> mod_mult_right_eq
   602 mod_mult1_eq'          -> mod_mult_left_eq
   603 mod_mult_distrib_mod   -> mod_mult_eq
   604 nat_mod_add_left_eq    -> mod_add_left_eq
   605 nat_mod_add_right_eq   -> mod_add_right_eq
   606 nat_mod_div_trivial    -> mod_div_trivial
   607 nat_mod_mod_trivial    -> mod_mod_trivial
   608 zdiv_zadd_self1        -> div_add_self1
   609 zdiv_zadd_self2        -> div_add_self2
   610 zdiv_zmult_self1       -> div_mult_self2_is_id
   611 zdiv_zmult_self2       -> div_mult_self1_is_id
   612 zdvd_triv_left         -> dvd_triv_left
   613 zdvd_triv_right        -> dvd_triv_right
   614 zdvd_zmult_cancel_disj -> dvd_mult_cancel_left
   615 zmod_eq0_zdvd_iff      -> dvd_eq_mod_eq_0[symmetric]
   616 zmod_zadd_left_eq      -> mod_add_left_eq
   617 zmod_zadd_right_eq     -> mod_add_right_eq
   618 zmod_zadd_self1        -> mod_add_self1
   619 zmod_zadd_self2        -> mod_add_self2
   620 zmod_zadd1_eq          -> mod_add_eq
   621 zmod_zdiff1_eq         -> mod_diff_eq
   622 zmod_zdvd_zmod         -> mod_mod_cancel
   623 zmod_zmod_cancel       -> mod_mod_cancel
   624 zmod_zmult_self1       -> mod_mult_self2_is_0
   625 zmod_zmult_self2       -> mod_mult_self1_is_0
   626 zmod_1                 -> mod_by_1
   627 zdiv_1                 -> div_by_1
   628 zdvd_abs1              -> abs_dvd_iff
   629 zdvd_abs2              -> dvd_abs_iff
   630 zdvd_refl              -> dvd_refl
   631 zdvd_trans             -> dvd_trans
   632 zdvd_zadd              -> dvd_add
   633 zdvd_zdiff             -> dvd_diff
   634 zdvd_zminus_iff        -> dvd_minus_iff
   635 zdvd_zminus2_iff       -> minus_dvd_iff
   636 zdvd_zmultD            -> dvd_mult_right
   637 zdvd_zmultD2           -> dvd_mult_left
   638 zdvd_zmult_mono        -> mult_dvd_mono
   639 zdvd_0_right           -> dvd_0_right
   640 zdvd_0_left            -> dvd_0_left_iff
   641 zdvd_1_left            -> one_dvd
   642 zminus_dvd_iff         -> minus_dvd_iff
   643 
   644 * Theory Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
   645 
   646 * The real numbers offer decimal input syntax: 12.34 is translated
   647 into 1234/10^2. This translation is not reversed upon output.
   648 
   649 * Theory Library/Polynomial defines an abstract type 'a poly of
   650 univariate polynomials with coefficients of type 'a.  In addition to
   651 the standard ring operations, it also supports div and mod.  Code
   652 generation is also supported, using list-style constructors.
   653 
   654 * Theory Library/Inner_Product defines a class of real_inner for real
   655 inner product spaces, with an overloaded operation inner :: 'a => 'a
   656 => real.  Class real_inner is a subclass of real_normed_vector from
   657 theory RealVector.
   658 
   659 * Theory Library/Product_Vector provides instances for the product
   660 type 'a * 'b of several classes from RealVector and Inner_Product.
   661 Definitions of addition, subtraction, scalar multiplication, norms,
   662 and inner products are included.
   663 
   664 * Theory Library/Bit defines the field "bit" of integers modulo 2.  In
   665 addition to the field operations, numerals and case syntax are also
   666 supported.
   667 
   668 * Theory Library/Diagonalize provides constructive version of Cantor's
   669 first diagonalization argument.
   670 
   671 * Theory Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
   672 zlcm (for int); carried together from various gcd/lcm developements in
   673 the HOL Distribution.  Constants zgcd and zlcm replace former igcd and
   674 ilcm; corresponding theorems renamed accordingly.  INCOMPATIBILITY,
   675 may recover tupled syntax as follows:
   676 
   677     hide (open) const gcd
   678     abbreviation gcd where
   679       "gcd == (%(a, b). GCD.gcd a b)"
   680     notation (output)
   681       GCD.gcd ("gcd '(_, _')")
   682 
   683 The same works for lcm, zgcd, zlcm.
   684 
   685 * Theory Library/Nat_Infinity: added addition, numeral syntax and more
   686 instantiations for algebraic structures.  Removed some duplicate
   687 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   688 
   689 * ML antiquotation @{code} takes a constant as argument and generates
   690 corresponding code in background and inserts name of the corresponding
   691 resulting ML value/function/datatype constructor binding in place.
   692 All occurrences of @{code} with a single ML block are generated
   693 simultaneously.  Provides a generic and safe interface for
   694 instrumentalizing code generation.  See
   695 src/HOL/Decision_Procs/Ferrack.thy for a more ambitious application.
   696 In future you ought to refrain from ad-hoc compiling generated SML
   697 code on the ML toplevel.  Note that (for technical reasons) @{code}
   698 cannot refer to constants for which user-defined serializations are
   699 set.  Refer to the corresponding ML counterpart directly in that
   700 cases.
   701 
   702 * Command 'rep_datatype': instead of theorem names the command now
   703 takes a list of terms denoting the constructors of the type to be
   704 represented as datatype.  The characteristic theorems have to be
   705 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   706 have disappeared in favour of existing ones:
   707 
   708     unit_induct                 ~> unit.induct
   709     prod_induct                 ~> prod.induct
   710     sum_induct                  ~> sum.induct
   711     Suc_Suc_eq                  ~> nat.inject
   712     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   713 
   714 
   715 *** HOL-Algebra ***
   716 
   717 * New locales for orders and lattices where the equivalence relation
   718 is not restricted to equality.  INCOMPATIBILITY: all order and lattice
   719 locales use a record structure with field eq for the equivalence.
   720 
   721 * New theory of factorial domains.
   722 
   723 * Units_l_inv and Units_r_inv are now simp rules by default.
   724 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   725 and/or r_inv will now also require deletion of these lemmas.
   726 
   727 * Renamed the following theorems, INCOMPATIBILITY:
   728 
   729 UpperD ~> Upper_memD
   730 LowerD ~> Lower_memD
   731 least_carrier ~> least_closed
   732 greatest_carrier ~> greatest_closed
   733 greatest_Lower_above ~> greatest_Lower_below
   734 one_zero ~> carrier_one_zero
   735 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   736 
   737 
   738 *** HOL-Nominal ***
   739 
   740 * Nominal datatypes can now contain type-variables.
   741 
   742 * Commands 'nominal_inductive' and 'equivariance' work with local
   743 theory targets.
   744 
   745 * Nominal primrec can now works with local theory targets and its
   746 specification syntax now conforms to the general format as seen in
   747 'inductive' etc.
   748 
   749 * Method "perm_simp" honours the standard simplifier attributes
   750 (no_asm), (no_asm_use) etc.
   751 
   752 * The new predicate #* is defined like freshness, except that on the
   753 left hand side can be a set or list of atoms.
   754 
   755 * Experimental command 'nominal_inductive2' derives strong induction
   756 principles for inductive definitions.  In contrast to
   757 'nominal_inductive', which can only deal with a fixed number of
   758 binders, it can deal with arbitrary expressions standing for sets of
   759 atoms to be avoided.  The only inductive definition we have at the
   760 moment that needs this generalisation is the typing rule for Lets in
   761 the algorithm W:
   762 
   763  Gamma |- t1 : T1   (x,close Gamma T1)::Gamma |- t2 : T2   x#Gamma
   764  -----------------------------------------------------------------
   765          Gamma |- Let x be t1 in t2 : T2
   766 
   767 In this rule one wants to avoid all the binders that are introduced by
   768 "close Gamma T1".  We are looking for other examples where this
   769 feature might be useful.  Please let us know.
   770 
   771 
   772 *** HOLCF ***
   773 
   774 * Reimplemented the simplification procedure for proving continuity
   775 subgoals.  The new simproc is extensible; users can declare additional
   776 continuity introduction rules with the attribute [cont2cont].
   777 
   778 * The continuity simproc now uses a different introduction rule for
   779 solving continuity subgoals on terms with lambda abstractions.  In
   780 some rare cases the new simproc may fail to solve subgoals that the
   781 old one could solve, and "simp add: cont2cont_LAM" may be necessary.
   782 Potential INCOMPATIBILITY.
   783 
   784 * Command 'fixrec': specification syntax now conforms to the general
   785 format as seen in 'inductive' etc.  See src/HOLCF/ex/Fixrec_ex.thy for
   786 examples.  INCOMPATIBILITY.
   787 
   788 
   789 *** ZF ***
   790 
   791 * Proof of Zorn's Lemma for partial orders.
   792 
   793 
   794 *** ML ***
   795 
   796 * Multithreading for Poly/ML 5.1/5.2 is no longer supported, only for
   797 Poly/ML 5.2.1 or later.  Important note: the TimeLimit facility
   798 depends on multithreading, so timouts will not work before Poly/ML
   799 5.2.1!
   800 
   801 * High-level support for concurrent ML programming, see
   802 src/Pure/Cuncurrent.  The data-oriented model of "future values" is
   803 particularly convenient to organize independent functional
   804 computations.  The concept of "synchronized variables" provides a
   805 higher-order interface for components with shared state, avoiding the
   806 delicate details of mutexes and condition variables.  (Requires
   807 Poly/ML 5.2.1 or later.)
   808 
   809 * ML bindings produced via Isar commands are stored within the Isar
   810 context (theory or proof).  Consequently, commands like 'use' and 'ML'
   811 become thread-safe and work with undo as expected (concerning
   812 top-level bindings, not side-effects on global references).
   813 INCOMPATIBILITY, need to provide proper Isar context when invoking the
   814 compiler at runtime; really global bindings need to be given outside a
   815 theory.  (Requires Poly/ML 5.2 or later.)
   816 
   817 * Command 'ML_prf' is analogous to 'ML' but works within a proof
   818 context.  Top-level ML bindings are stored within the proof context in
   819 a purely sequential fashion, disregarding the nested proof structure.
   820 ML bindings introduced by 'ML_prf' are discarded at the end of the
   821 proof.  (Requires Poly/ML 5.2 or later.)
   822 
   823 * Simplified ML attribute and method setup, cf. functions Attrib.setup
   824 and Method.setup, as well as Isar commands 'attribute_setup' and
   825 'method_setup'.  INCOMPATIBILITY for 'method_setup', need to simplify
   826 existing code accordingly, or use plain 'setup' together with old
   827 Method.add_method.
   828 
   829 * Simplified ML oracle interface Thm.add_oracle promotes 'a -> cterm
   830 to 'a -> thm, while results are always tagged with an authentic oracle
   831 name.  The Isar command 'oracle' is now polymorphic, no argument type
   832 is specified.  INCOMPATIBILITY, need to simplify existing oracle code
   833 accordingly.  Note that extra performance may be gained by producing
   834 the cterm carefully, avoiding slow Thm.cterm_of.
   835 
   836 * Simplified interface for defining document antiquotations via
   837 ThyOutput.antiquotation, ThyOutput.output, and optionally
   838 ThyOutput.maybe_pretty_source.  INCOMPATIBILITY, need to simplify user
   839 antiquotations accordingly, see src/Pure/Thy/thy_output.ML for common
   840 examples.
   841 
   842 * More systematic treatment of long names, abstract name bindings, and
   843 name space operations.  Basic operations on qualified names have been
   844 move from structure NameSpace to Long_Name, e.g. Long_Name.base_name,
   845 Long_Name.append.  Old type bstring has been mostly replaced by
   846 abstract type binding (see structure Binding), which supports precise
   847 qualification by packages and local theory targets, as well as proper
   848 tracking of source positions.  INCOMPATIBILITY, need to wrap old
   849 bstring values into Binding.name, or better pass through abstract
   850 bindings everywhere.  See further src/Pure/General/long_name.ML,
   851 src/Pure/General/binding.ML and src/Pure/General/name_space.ML
   852 
   853 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   854 LocalTheory.note etc.) now refer to the *full* internal name, not the
   855 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   856 
   857 * Disposed old type and term read functions (Sign.read_def_typ,
   858 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   859 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   860 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   861 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   862 resort for legacy applications.
   863 
   864 * Disposed old declarations, tactics, tactic combinators that refer to
   865 the simpset or claset of an implicit theory (such as Addsimps,
   866 Simp_tac, SIMPSET).  INCOMPATIBILITY, should use @{simpset} etc. in
   867 embedded ML text, or local_simpset_of with a proper context passed as
   868 explicit runtime argument.
   869 
   870 * Rules and tactics that read instantiations (read_instantiate,
   871 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   872 context, which is required for parsing and type-checking.  Moreover,
   873 the variables are specified as plain indexnames, not string encodings
   874 thereof.  INCOMPATIBILITY.
   875 
   876 * Generic Toplevel.add_hook interface allows to analyze the result of
   877 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   878 for theorem dependency output of transactions resulting in a new
   879 theory state.
   880 
   881 * ML antiquotations: block-structured compilation context indicated by
   882 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   883 
   884   @{binding name}                         - basic name binding
   885   @{let ?pat = term}                      - term abbreviation (HO matching)
   886   @{note name = fact}                     - fact abbreviation
   887   @{thm fact}                             - singleton fact (with attributes)
   888   @{thms fact}                            - general fact (with attributes)
   889   @{lemma prop by method}                 - singleton goal
   890   @{lemma prop by meth1 meth2}            - singleton goal
   891   @{lemma prop1 ... propN by method}      - general goal
   892   @{lemma prop1 ... propN by meth1 meth2} - general goal
   893   @{lemma (open) ...}                     - open derivation
   894 
   895 
   896 *** System ***
   897 
   898 * The Isabelle "emacs" tool provides a specific interface to invoke
   899 Proof General / Emacs, with more explicit failure if that is not
   900 installed (the old isabelle-interface script silently falls back on
   901 isabelle-process).  The PROOFGENERAL_HOME setting determines the
   902 installation location of the Proof General distribution.
   903 
   904 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   905 the Isabelle process into a JVM/Scala application.  See
   906 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   907 process wrapper has been discontinued.)
   908 
   909 * Added homegrown Isabelle font with unicode layout, see lib/fonts.
   910 
   911 * Various status messages (with exact source position information) are
   912 emitted, if proper markup print mode is enabled.  This allows
   913 user-interface components to provide detailed feedback on internal
   914 prover operations.
   915 
   916 
   917 
   918 New in Isabelle2008 (June 2008)
   919 -------------------------------
   920 
   921 *** General ***
   922 
   923 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   924 and updated, with formally checked references as hyperlinks.
   925 
   926 * Theory loader: use_thy (and similar operations) no longer set the
   927 implicit ML context, which was occasionally hard to predict and in
   928 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   929 provides a proper context already.
   930 
   931 * Theory loader: old-style ML proof scripts being *attached* to a thy
   932 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   933 'use' within a theory file will do the job.
   934 
   935 * Name space merge now observes canonical order, i.e. the second space
   936 is inserted into the first one, while existing entries in the first
   937 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   938 swap theory imports.
   939 
   940 * Syntax: symbol \<chi> is now considered a letter.  Potential
   941 INCOMPATIBILITY in identifier syntax etc.
   942 
   943 * Outer syntax: string tokens no longer admit escaped white space,
   944 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   945 white space without escapes.
   946 
   947 * Outer syntax: string tokens may contain arbitrary character codes
   948 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   949 "foo_bar".
   950 
   951 
   952 *** Pure ***
   953 
   954 * Context-dependent token translations.  Default setup reverts locally
   955 fixed variables, and adds hilite markup for undeclared frees.
   956 
   957 * Unused theorems can be found using the new command 'unused_thms'.
   958 There are three ways of invoking it:
   959 
   960 (1) unused_thms
   961      Only finds unused theorems in the current theory.
   962 
   963 (2) unused_thms thy_1 ... thy_n -
   964      Finds unused theorems in the current theory and all of its ancestors,
   965      excluding the theories thy_1 ... thy_n and all of their ancestors.
   966 
   967 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   968      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   969      their ancestors, excluding the theories thy_1 ... thy_n and all of
   970      their ancestors.
   971 
   972 In order to increase the readability of the list produced by
   973 unused_thms, theorems that have been created by a particular instance
   974 of a theory command such as 'inductive' or 'function' are considered
   975 to belong to the same "group", meaning that if at least one theorem in
   976 this group is used, the other theorems in the same group are no longer
   977 reported as unused.  Moreover, if all theorems in the group are
   978 unused, only one theorem in the group is displayed.
   979 
   980 Note that proof objects have to be switched on in order for
   981 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   982 usually the case when using Proof General with the default settings).
   983 
   984 * Authentic naming of facts disallows ad-hoc overwriting of previous
   985 theorems within the same name space.  INCOMPATIBILITY, need to remove
   986 duplicate fact bindings, or even accidental fact duplications.  Note
   987 that tools may maintain dynamically scoped facts systematically, using
   988 PureThy.add_thms_dynamic.
   989 
   990 * Command 'hide' now allows to hide from "fact" name space as well.
   991 
   992 * Eliminated destructive theorem database, simpset, claset, and
   993 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   994 update of theories within ML code.
   995 
   996 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   997 INCOMPATIBILITY, object-logics depending on former Pure require
   998 additional setup PureThy.old_appl_syntax_setup; object-logics
   999 depending on former CPure need to refer to Pure.
  1000 
  1001 * Commands 'use' and 'ML' are now purely functional, operating on
  1002 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
  1003 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
  1004 INCOMPATIBILITY.
  1005 
  1006 * Command 'setup': discontinued implicit version with ML reference.
  1007 
  1008 * Instantiation target allows for simultaneous specification of class
  1009 instance operations together with an instantiation proof.
  1010 Type-checking phase allows to refer to class operations uniformly.
  1011 See src/HOL/Complex/Complex.thy for an Isar example and
  1012 src/HOL/Library/Eval.thy for an ML example.
  1013 
  1014 * Indexing of literal facts: be more serious about including only
  1015 facts from the visible specification/proof context, but not the
  1016 background context (locale etc.).  Affects `prop` notation and method
  1017 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
  1018 situations.
  1019 
  1020 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
  1021 "(open)" option, which used to expose internal bound variables to the
  1022 proof text.
  1023 
  1024 * Isar statements: removed obsolete case "rule_context".
  1025 INCOMPATIBILITY, better use explicit fixes/assumes.
  1026 
  1027 * Locale proofs: default proof step now includes 'unfold_locales';
  1028 hence 'proof' without argument may be used to unfold locale
  1029 predicates.
  1030 
  1031 
  1032 *** Document preparation ***
  1033 
  1034 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
  1035 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
  1036 obsolete thumbpdf setup (contemporary PDF viewers do this on the
  1037 spot); renamed link color from "darkblue" to "linkcolor" (default
  1038 value unchanged, can be redefined via \definecolor); no longer sets
  1039 "a4paper" option (unnecessary or even intrusive).
  1040 
  1041 * Antiquotation @{lemma A method} proves proposition A by the given
  1042 method (either a method name or a method name plus (optional) method
  1043 arguments in parentheses) and prints A just like @{prop A}.
  1044 
  1045 
  1046 *** HOL ***
  1047 
  1048 * New primrec package.  Specification syntax conforms in style to
  1049 definition/function/....  No separate induction rule is provided.  The
  1050 "primrec" command distinguishes old-style and new-style specifications
  1051 by syntax.  The former primrec package is now named OldPrimrecPackage.
  1052 When adjusting theories, beware: constants stemming from new-style
  1053 primrec specifications have authentic syntax.
  1054 
  1055 * Metis prover is now an order of magnitude faster, and also works
  1056 with multithreading.
  1057 
  1058 * Metis: the maximum number of clauses that can be produced from a
  1059 theorem is now given by the attribute max_clauses.  Theorems that
  1060 exceed this number are ignored, with a warning printed.
  1061 
  1062 * Sledgehammer no longer produces structured proofs by default. To
  1063 enable, declare [[sledgehammer_full = true]].  Attributes
  1064 reconstruction_modulus, reconstruction_sorts renamed
  1065 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
  1066 
  1067 * Method "induct_scheme" derives user-specified induction rules
  1068 from well-founded induction and completeness of patterns. This factors
  1069 out some operations that are done internally by the function package
  1070 and makes them available separately.  See
  1071 src/HOL/ex/Induction_Scheme.thy for examples.
  1072 
  1073 * More flexible generation of measure functions for termination
  1074 proofs: Measure functions can be declared by proving a rule of the
  1075 form "is_measure f" and giving it the [measure_function] attribute.
  1076 The "is_measure" predicate is logically meaningless (always true), and
  1077 just guides the heuristic.  To find suitable measure functions, the
  1078 termination prover sets up the goal "is_measure ?f" of the appropriate
  1079 type and generates all solutions by prolog-style backwards proof using
  1080 the declared rules.
  1081 
  1082 This setup also deals with rules like 
  1083 
  1084   "is_measure f ==> is_measure (list_size f)"
  1085 
  1086 which accommodates nested datatypes that recurse through lists.
  1087 Similar rules are predeclared for products and option types.
  1088 
  1089 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
  1090 
  1091   INCOMPATIBILITIES:
  1092 
  1093   - Definitions of overloaded constants on sets have to be replaced by
  1094     definitions on => and bool.
  1095 
  1096   - Some definitions of overloaded operators on sets can now be proved
  1097     using the definitions of the operators on => and bool.  Therefore,
  1098     the following theorems have been renamed:
  1099 
  1100       subset_def   -> subset_eq
  1101       psubset_def  -> psubset_eq
  1102       set_diff_def -> set_diff_eq
  1103       Compl_def    -> Compl_eq
  1104       Sup_set_def  -> Sup_set_eq
  1105       Inf_set_def  -> Inf_set_eq
  1106       sup_set_def  -> sup_set_eq
  1107       inf_set_def  -> inf_set_eq
  1108 
  1109   - Due to the incompleteness of the HO unification algorithm, some
  1110     rules such as subst may require manual instantiation, if some of
  1111     the unknowns in the rule is a set.
  1112 
  1113   - Higher order unification and forward proofs:
  1114     The proof pattern
  1115 
  1116       have "P (S::'a set)" <...>
  1117       then have "EX S. P S" ..
  1118 
  1119     no longer works (due to the incompleteness of the HO unification
  1120     algorithm) and must be replaced by the pattern
  1121 
  1122       have "EX S. P S"
  1123       proof
  1124         show "P S" <...>
  1125       qed
  1126 
  1127   - Calculational reasoning with subst (or similar rules):
  1128     The proof pattern
  1129 
  1130       have "P (S::'a set)" <...>
  1131       also have "S = T" <...>
  1132       finally have "P T" .
  1133 
  1134     no longer works (for similar reasons as the previous example) and
  1135     must be replaced by something like
  1136 
  1137       have "P (S::'a set)" <...>
  1138       moreover have "S = T" <...>
  1139       ultimately have "P T" by simp
  1140 
  1141   - Tactics or packages written in ML code:
  1142     Code performing pattern matching on types via
  1143 
  1144       Type ("set", [T]) => ...
  1145 
  1146     must be rewritten. Moreover, functions like strip_type or
  1147     binder_types no longer return the right value when applied to a
  1148     type of the form
  1149 
  1150       T1 => ... => Tn => U => bool
  1151 
  1152     rather than
  1153 
  1154       T1 => ... => Tn => U set
  1155 
  1156 * Merged theories Wellfounded_Recursion, Accessible_Part and
  1157 Wellfounded_Relations to theory Wellfounded.
  1158 
  1159 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
  1160 
  1161 * Class finite no longer treats UNIV as class parameter.  Use class
  1162 enum from theory Library/Enum instead to achieve a similar effect.
  1163 INCOMPATIBILITY.
  1164 
  1165 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
  1166 and "Cons".  INCOMPATIBILITY.
  1167 
  1168 * HOL (and FOL): renamed variables in rules imp_elim and swap.
  1169 Potential INCOMPATIBILITY.
  1170 
  1171 * Theory Product_Type: duplicated lemmas split_Pair_apply and
  1172 injective_fst_snd removed, use split_eta and prod_eqI instead.
  1173 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
  1174 
  1175 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
  1176 the same name in theory Orderings:
  1177 
  1178   less_trans
  1179   less_linear
  1180   le_imp_less_or_eq
  1181   le_less_trans
  1182   less_le_trans
  1183   less_not_sym
  1184   less_asym
  1185 
  1186 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
  1187 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
  1188 and different variable names.
  1189 
  1190 * Library/Option_ord.thy: Canonical order on option type.
  1191 
  1192 * Library/RBT.thy: Red-black trees, an efficient implementation of
  1193 finite maps.
  1194 
  1195 * Library/Countable.thy: Type class for countable types.
  1196 
  1197 * Theory Int: The representation of numerals has changed.  The infix
  1198 operator BIT and the bit datatype with constructors B0 and B1 have
  1199 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
  1200 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
  1201 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
  1202 accordingly.
  1203 
  1204 * Theory Nat: definition of <= and < on natural numbers no longer
  1205 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
  1206 le_def and less_def have disappeared.  Consider lemmas not_less
  1207 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
  1208 
  1209 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
  1210 (whose purpose mainly is for various fold_set functionals) have been
  1211 abandoned in favor of the existing algebraic classes
  1212 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
  1213 lower_semilattice (resp. upper_semilattice) and linorder.
  1214 INCOMPATIBILITY.
  1215 
  1216 * Theory Transitive_Closure: induct and cases rules now declare proper
  1217 case_names ("base" and "step").  INCOMPATIBILITY.
  1218 
  1219 * Theorem Inductive.lfp_ordinal_induct generalized to complete
  1220 lattices.  The form set-specific version is available as
  1221 Inductive.lfp_ordinal_induct_set.
  1222 
  1223 * Renamed theorems "power.simps" to "power_int.simps".
  1224 INCOMPATIBILITY.
  1225 
  1226 * Class semiring_div provides basic abstract properties of semirings
  1227 with division and modulo operations.  Subsumes former class dvd_mod.
  1228 
  1229 * Merged theories IntDef, Numeral and IntArith into unified theory
  1230 Int.  INCOMPATIBILITY.
  1231 
  1232 * Theory Library/Code_Index: type "index" now represents natural
  1233 numbers rather than integers.  INCOMPATIBILITY.
  1234 
  1235 * New class "uminus" with operation "uminus" (split of from class
  1236 "minus" which now only has operation "minus", binary).
  1237 INCOMPATIBILITY.
  1238 
  1239 * Constants "card", "internal_split", "option_map" now with authentic
  1240 syntax.  INCOMPATIBILITY.
  1241 
  1242 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
  1243 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
  1244 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
  1245 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
  1246 Sup_set_def, le_def, less_def, option_map_def now with object
  1247 equality.  INCOMPATIBILITY.
  1248 
  1249 * Records. Removed K_record, and replaced it by pure lambda term
  1250 %x. c. The simplifier setup is now more robust against eta expansion.
  1251 INCOMPATIBILITY: in cases explicitly referring to K_record.
  1252 
  1253 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
  1254 
  1255 * Library/ListVector: new theory of arithmetic vector operations.
  1256 
  1257 * Library/Order_Relation: new theory of various orderings as sets of
  1258 pairs.  Defines preorders, partial orders, linear orders and
  1259 well-orders on sets and on types.
  1260 
  1261 
  1262 *** ZF ***
  1263 
  1264 * Renamed some theories to allow to loading both ZF and HOL in the
  1265 same session:
  1266 
  1267   Datatype  -> Datatype_ZF
  1268   Inductive -> Inductive_ZF
  1269   Int       -> Int_ZF
  1270   IntDiv    -> IntDiv_ZF
  1271   Nat       -> Nat_ZF
  1272   List      -> List_ZF
  1273   Main      -> Main_ZF
  1274 
  1275 INCOMPATIBILITY: ZF theories that import individual theories below
  1276 Main might need to be adapted.  Regular theory Main is still
  1277 available, as trivial extension of Main_ZF.
  1278 
  1279 
  1280 *** ML ***
  1281 
  1282 * ML within Isar: antiquotation @{const name} or @{const
  1283 name(typargs)} produces statically-checked Const term.
  1284 
  1285 * Functor NamedThmsFun: data is available to the user as dynamic fact
  1286 (of the same name).  Removed obsolete print command.
  1287 
  1288 * Removed obsolete "use_legacy_bindings" function.
  1289 
  1290 * The ``print mode'' is now a thread-local value derived from a global
  1291 template (the former print_mode reference), thus access becomes
  1292 non-critical.  The global print_mode reference is for session
  1293 management only; user-code should use print_mode_value,
  1294 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
  1295 
  1296 * Functions system/system_out provide a robust way to invoke external
  1297 shell commands, with propagation of interrupts (requires Poly/ML
  1298 5.2.1).  Do not use OS.Process.system etc. from the basis library!
  1299 
  1300 
  1301 *** System ***
  1302 
  1303 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
  1304 in accordance with Proof General 3.7, which prefers GNU emacs.
  1305 
  1306 * isatool tty runs Isabelle process with plain tty interaction;
  1307 optional line editor may be specified via ISABELLE_LINE_EDITOR
  1308 setting, the default settings attempt to locate "ledit" and "rlwrap".
  1309 
  1310 * isatool browser now works with Cygwin as well, using general
  1311 "javapath" function defined in Isabelle process environment.
  1312 
  1313 * YXML notation provides a simple and efficient alternative to
  1314 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
  1315 isatool yxml as described in the Isabelle system manual.
  1316 
  1317 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
  1318 provides general wrapper for managing an Isabelle process in a robust
  1319 fashion, with ``cooked'' output from stdin/stderr.
  1320 
  1321 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
  1322 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
  1323 
  1324 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
  1325 way of changing the user's settings is via
  1326 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
  1327 script.
  1328 
  1329 * Multithreading.max_threads := 0 refers to the number of actual CPU
  1330 cores of the underlying machine, which is a good starting point for
  1331 optimal performance tuning.  The corresponding usedir option -M allows
  1332 "max" as an alias for "0".  WARNING: does not work on certain versions
  1333 of Mac OS (with Poly/ML 5.1).
  1334 
  1335 * isabelle-process: non-ML sessions are run with "nice", to reduce the
  1336 adverse effect of Isabelle flooding interactive front-ends (notably
  1337 ProofGeneral / XEmacs).
  1338 
  1339 
  1340 
  1341 New in Isabelle2007 (November 2007)
  1342 -----------------------------------
  1343 
  1344 *** General ***
  1345 
  1346 * More uniform information about legacy features, notably a
  1347 warning/error of "Legacy feature: ...", depending on the state of the
  1348 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
  1349 legacy features will disappear eventually.
  1350 
  1351 * Theory syntax: the header format ``theory A = B + C:'' has been
  1352 discontinued in favour of ``theory A imports B C begin''.  Use isatool
  1353 fixheaders to convert existing theory files.  INCOMPATIBILITY.
  1354 
  1355 * Theory syntax: the old non-Isar theory file format has been
  1356 discontinued altogether.  Note that ML proof scripts may still be used
  1357 with Isar theories; migration is usually quite simple with the ML
  1358 function use_legacy_bindings.  INCOMPATIBILITY.
  1359 
  1360 * Theory syntax: some popular names (e.g. 'class', 'declaration',
  1361 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
  1362 quotes.
  1363 
  1364 * Theory loader: be more serious about observing the static theory
  1365 header specifications (including optional directories), but not the
  1366 accidental file locations of previously successful loads.  The strict
  1367 update policy of former update_thy is now already performed by
  1368 use_thy, so the former has been removed; use_thys updates several
  1369 theories simultaneously, just as 'imports' within a theory header
  1370 specification, but without merging the results.  Potential
  1371 INCOMPATIBILITY: may need to refine theory headers and commands
  1372 ROOT.ML which depend on load order.
  1373 
  1374 * Theory loader: optional support for content-based file
  1375 identification, instead of the traditional scheme of full physical
  1376 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
  1377 (cf. the system manual).  The new scheme allows to work with
  1378 non-finished theories in persistent session images, such that source
  1379 files may be moved later on without requiring reloads.
  1380 
  1381 * Theory loader: old-style ML proof scripts being *attached* to a thy
  1382 file (with the same base name as the theory) are considered a legacy
  1383 feature, which will disappear eventually. Even now, the theory loader
  1384 no longer maintains dependencies on such files.
  1385 
  1386 * Syntax: the scope for resolving ambiguities via type-inference is
  1387 now limited to individual terms, instead of whole simultaneous
  1388 specifications as before. This greatly reduces the complexity of the
  1389 syntax module and improves flexibility by separating parsing and
  1390 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
  1391 'fixes' etc.) are required in rare situations.
  1392 
  1393 * Syntax: constants introduced by new-style packages ('definition',
  1394 'abbreviation' etc.) are passed through the syntax module in
  1395 ``authentic mode''. This means that associated mixfix annotations
  1396 really stick to such constants, independently of potential name space
  1397 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
  1398 trees are represented slightly differently, may need to adapt syntax
  1399 translations accordingly. Use CONST marker in 'translations' and
  1400 @{const_syntax} antiquotation in 'parse_translation' etc.
  1401 
  1402 * Legacy goal package: reduced interface to the bare minimum required
  1403 to keep existing proof scripts running.  Most other user-level
  1404 functions are now part of the OldGoals structure, which is *not* open
  1405 by default (consider isatool expandshort before open OldGoals).
  1406 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
  1407 these tend to cause confusion about the actual goal (!) context being
  1408 used here, which is not necessarily the same as the_context().
  1409 
  1410 * Command 'find_theorems': supports "*" wild-card in "name:"
  1411 criterion; "with_dups" option.  Certain ProofGeneral versions might
  1412 support a specific search form (see ProofGeneral/CHANGES).
  1413 
  1414 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
  1415 by default, which means that "prems" (and also "fixed variables") are
  1416 suppressed from proof state output.  Note that the ProofGeneral
  1417 settings mechanism allows to change and save options persistently, but
  1418 older versions of Isabelle will fail to start up if a negative prems
  1419 limit is imposed.
  1420 
  1421 * Local theory targets may be specified by non-nested blocks of
  1422 ``context/locale/class ... begin'' followed by ``end''.  The body may
  1423 contain definitions, theorems etc., including any derived mechanism
  1424 that has been implemented on top of these primitives.  This concept
  1425 generalizes the existing ``theorem (in ...)'' towards more versatility
  1426 and scalability.
  1427 
  1428 * Proof General interface: proper undo of final 'end' command;
  1429 discontinued Isabelle/classic mode (ML proof scripts).
  1430 
  1431 
  1432 *** Document preparation ***
  1433 
  1434 * Added antiquotation @{theory name} which prints the given name,
  1435 after checking that it refers to a valid ancestor theory in the
  1436 current context.
  1437 
  1438 * Added antiquotations @{ML_type text} and @{ML_struct text} which
  1439 check the given source text as ML type/structure, printing verbatim.
  1440 
  1441 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
  1442 "c args == rhs" given in the current context.  (Any number of
  1443 arguments may be given on the LHS.)
  1444 
  1445 
  1446 *** Pure ***
  1447 
  1448 * The 'class' package offers a combination of axclass and locale to
  1449 achieve Haskell-like type classes in Isabelle.  Definitions and
  1450 theorems within a class context produce both relative results (with
  1451 implicit parameters according to the locale context), and polymorphic
  1452 constants with qualified polymorphism (according to the class
  1453 context).  Within the body context of a 'class' target, a separate
  1454 syntax layer ("user space type system") takes care of converting
  1455 between global polymorphic consts and internal locale representation.
  1456 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
  1457 "isatool doc classes" provides a tutorial.
  1458 
  1459 * Generic code generator framework allows to generate executable
  1460 code for ML and Haskell (including Isabelle classes).  A short usage
  1461 sketch:
  1462 
  1463     internal compilation:
  1464         export_code <list of constants (term syntax)> in SML
  1465     writing SML code to a file:
  1466         export_code <list of constants (term syntax)> in SML <filename>
  1467     writing OCaml code to a file:
  1468         export_code <list of constants (term syntax)> in OCaml <filename>
  1469     writing Haskell code to a bunch of files:
  1470         export_code <list of constants (term syntax)> in Haskell <filename>
  1471 
  1472     evaluating closed propositions to True/False using code generation:
  1473         method ``eval''
  1474 
  1475 Reasonable default setup of framework in HOL.
  1476 
  1477 Theorem attributs for selecting and transforming function equations theorems:
  1478 
  1479     [code fun]:        select a theorem as function equation for a specific constant
  1480     [code fun del]:    deselect a theorem as function equation for a specific constant
  1481     [code inline]:     select an equation theorem for unfolding (inlining) in place
  1482     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
  1483 
  1484 User-defined serializations (target in {SML, OCaml, Haskell}):
  1485 
  1486     code_const <and-list of constants (term syntax)>
  1487       {(target) <and-list of const target syntax>}+
  1488 
  1489     code_type <and-list of type constructors>
  1490       {(target) <and-list of type target syntax>}+
  1491 
  1492     code_instance <and-list of instances>
  1493       {(target)}+
  1494         where instance ::= <type constructor> :: <class>
  1495 
  1496     code_class <and_list of classes>
  1497       {(target) <and-list of class target syntax>}+
  1498         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
  1499 
  1500 code_instance and code_class only are effective to target Haskell.
  1501 
  1502 For example usage see src/HOL/ex/Codegenerator.thy and
  1503 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
  1504 generation from Isabelle/HOL theories is available via "isatool doc
  1505 codegen".
  1506 
  1507 * Code generator: consts in 'consts_code' Isar commands are now
  1508 referred to by usual term syntax (including optional type
  1509 annotations).
  1510 
  1511 * Command 'no_translations' removes translation rules from theory
  1512 syntax.
  1513 
  1514 * Overloaded definitions are now actually checked for acyclic
  1515 dependencies.  The overloading scheme is slightly more general than
  1516 that of Haskell98, although Isabelle does not demand an exact
  1517 correspondence to type class and instance declarations.
  1518 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
  1519 exotic versions of overloading -- at the discretion of the user!
  1520 
  1521 Polymorphic constants are represented via type arguments, i.e. the
  1522 instantiation that matches an instance against the most general
  1523 declaration given in the signature.  For example, with the declaration
  1524 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
  1525 as c(nat).  Overloading is essentially simultaneous structural
  1526 recursion over such type arguments.  Incomplete specification patterns
  1527 impose global constraints on all occurrences, e.g. c('a * 'a) on the
  1528 LHS means that more general c('a * 'b) will be disallowed on any RHS.
  1529 Command 'print_theory' outputs the normalized system of recursive
  1530 equations, see section "definitions".
  1531 
  1532 * Configuration options are maintained within the theory or proof
  1533 context (with name and type bool/int/string), providing a very simple
  1534 interface to a poor-man's version of general context data.  Tools may
  1535 declare options in ML (e.g. using Attrib.config_int) and then refer to
  1536 these values using Config.get etc.  Users may change options via an
  1537 associated attribute of the same name.  This form of context
  1538 declaration works particularly well with commands 'declare' or
  1539 'using', for example ``declare [[foo = 42]]''.  Thus it has become
  1540 very easy to avoid global references, which would not observe Isar
  1541 toplevel undo/redo and fail to work with multithreading.
  1542 
  1543 Various global ML references of Pure and HOL have been turned into
  1544 configuration options:
  1545 
  1546   Unify.search_bound		unify_search_bound
  1547   Unify.trace_bound		unify_trace_bound
  1548   Unify.trace_simp		unify_trace_simp
  1549   Unify.trace_types		unify_trace_types
  1550   Simplifier.simp_depth_limit	simp_depth_limit
  1551   Blast.depth_limit		blast_depth_limit
  1552   DatatypeProp.dtK		datatype_distinctness_limit
  1553   fast_arith_neq_limit  	fast_arith_neq_limit
  1554   fast_arith_split_limit	fast_arith_split_limit
  1555 
  1556 * Named collections of theorems may be easily installed as context
  1557 data using the functor NamedThmsFun (see also
  1558 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
  1559 attributes; there is also a toplevel print command.  This facility is
  1560 just a common case of general context data, which is the preferred way
  1561 for anything more complex than just a list of facts in canonical
  1562 order.
  1563 
  1564 * Isar: command 'declaration' augments a local theory by generic
  1565 declaration functions written in ML.  This enables arbitrary content
  1566 being added to the context, depending on a morphism that tells the
  1567 difference of the original declaration context wrt. the application
  1568 context encountered later on.
  1569 
  1570 * Isar: proper interfaces for simplification procedures.  Command
  1571 'simproc_setup' declares named simprocs (with match patterns, and body
  1572 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
  1573 context.  ML antiquotation @{simproc name} retrieves named simprocs.
  1574 
  1575 * Isar: an extra pair of brackets around attribute declarations
  1576 abbreviates a theorem reference involving an internal dummy fact,
  1577 which will be ignored later --- only the effect of the attribute on
  1578 the background context will persist.  This form of in-place
  1579 declarations is particularly useful with commands like 'declare' and
  1580 'using', for example ``have A using [[simproc a]] by simp''.
  1581 
  1582 * Isar: method "assumption" (and implicit closing of subproofs) now
  1583 takes simple non-atomic goal assumptions into account: after applying
  1584 an assumption as a rule the resulting subgoals are solved by atomic
  1585 assumption steps.  This is particularly useful to finish 'obtain'
  1586 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
  1587 without referring to the original premise "!!x. P x ==> thesis" in the
  1588 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
  1589 more permissive.
  1590 
  1591 * Isar: implicit use of prems from the Isar proof context is
  1592 considered a legacy feature.  Common applications like ``have A .''
  1593 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
  1594 referencing facts explicitly here improves readability and
  1595 maintainability of proof texts.
  1596 
  1597 * Isar: improper proof element 'guess' is like 'obtain', but derives
  1598 the obtained context from the course of reasoning!  For example:
  1599 
  1600   assume "EX x y. A x & B y"   -- "any previous fact"
  1601   then guess x and y by clarify
  1602 
  1603 This technique is potentially adventurous, depending on the facts and
  1604 proof tools being involved here.
  1605 
  1606 * Isar: known facts from the proof context may be specified as literal
  1607 propositions, using ASCII back-quote syntax.  This works wherever
  1608 named facts used to be allowed so far, in proof commands, proof
  1609 methods, attributes etc.  Literal facts are retrieved from the context
  1610 according to unification of type and term parameters.  For example,
  1611 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
  1612 theorems in the current context, then these are valid literal facts:
  1613 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
  1614 
  1615 There is also a proof method "fact" which does the same composition
  1616 for explicit goal states, e.g. the following proof texts coincide with
  1617 certain special cases of literal facts:
  1618 
  1619   have "A" by fact                 ==  note `A`
  1620   have "A ==> B" by fact           ==  note `A ==> B`
  1621   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
  1622   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
  1623 
  1624 * Isar: ":" (colon) is no longer a symbolic identifier character in
  1625 outer syntax.  Thus symbolic identifiers may be used without
  1626 additional white space in declarations like this: ``assume *: A''.
  1627 
  1628 * Isar: 'print_facts' prints all local facts of the current context,
  1629 both named and unnamed ones.
  1630 
  1631 * Isar: 'def' now admits simultaneous definitions, e.g.:
  1632 
  1633   def x == "t" and y == "u"
  1634 
  1635 * Isar: added command 'unfolding', which is structurally similar to
  1636 'using', but affects both the goal state and facts by unfolding given
  1637 rewrite rules.  Thus many occurrences of the 'unfold' method or
  1638 'unfolded' attribute may be replaced by first-class proof text.
  1639 
  1640 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
  1641 and command 'unfolding' now all support object-level equalities
  1642 (potentially conditional).  The underlying notion of rewrite rule is
  1643 analogous to the 'rule_format' attribute, but *not* that of the
  1644 Simplifier (which is usually more generous).
  1645 
  1646 * Isar: the new attribute [rotated n] (default n = 1) rotates the
  1647 premises of a theorem by n. Useful in conjunction with drule.
  1648 
  1649 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
  1650 method expression within a sandbox consisting of the first N
  1651 sub-goals, which need to exist.  For example, ``simp_all [3]''
  1652 simplifies the first three sub-goals, while (rule foo, simp_all)[]
  1653 simplifies all new goals that emerge from applying rule foo to the
  1654 originally first one.
  1655 
  1656 * Isar: schematic goals are no longer restricted to higher-order
  1657 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
  1658 expected.
  1659 
  1660 * Isar: the conclusion of a long theorem statement is now either
  1661 'shows' (a simultaneous conjunction, as before), or 'obtains'
  1662 (essentially a disjunction of cases with local parameters and
  1663 assumptions).  The latter allows to express general elimination rules
  1664 adequately; in this notation common elimination rules look like this:
  1665 
  1666   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
  1667     assumes "EX x. P x"
  1668     obtains x where "P x"
  1669 
  1670   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
  1671     assumes "A & B"
  1672     obtains A and B
  1673 
  1674   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1675     assumes "A | B"
  1676     obtains
  1677       A
  1678     | B
  1679 
  1680 The subsequent classical rules even refer to the formal "thesis"
  1681 explicitly:
  1682 
  1683   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1684     obtains "~ thesis"
  1685 
  1686   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1687     obtains "thesis ==> something"
  1688 
  1689 The actual proof of an 'obtains' statement is analogous to that of the
  1690 Isar proof element 'obtain', only that there may be several cases.
  1691 Optional case names may be specified in parentheses; these will be
  1692 available both in the present proof and as annotations in the
  1693 resulting rule, for later use with the 'cases' method (cf. attribute
  1694 case_names).
  1695 
  1696 * Isar: the assumptions of a long theorem statement are available as
  1697 "assms" fact in the proof context.  This is more appropriate than the
  1698 (historical) "prems", which refers to all assumptions of the current
  1699 context, including those from the target locale, proof body etc.
  1700 
  1701 * Isar: 'print_statement' prints theorems from the current theory or
  1702 proof context in long statement form, according to the syntax of a
  1703 top-level lemma.
  1704 
  1705 * Isar: 'obtain' takes an optional case name for the local context
  1706 introduction rule (default "that").
  1707 
  1708 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1709 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1710 to occur.
  1711 
  1712 * Pure: syntax "CONST name" produces a fully internalized constant
  1713 according to the current context.  This is particularly useful for
  1714 syntax translations that should refer to internal constant
  1715 representations independently of name spaces.
  1716 
  1717 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1718 instead of "FOO ". This allows multiple binder declarations to coexist
  1719 in the same context.  INCOMPATIBILITY.
  1720 
  1721 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1722 primitive that also works in a locale context (both for constants and
  1723 fixed variables). Type declaration and internal syntactic representation
  1724 of given constants retrieved from the context. Likewise, the
  1725 'no_notation' command allows to remove given syntax annotations from the
  1726 current context.
  1727 
  1728 * Isar/locales: new derived specification elements 'axiomatization',
  1729 'definition', 'abbreviation', which support type-inference, admit
  1730 object-level specifications (equality, equivalence).  See also the
  1731 isar-ref manual.  Examples:
  1732 
  1733   axiomatization
  1734     eq  (infix "===" 50) where
  1735     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1736 
  1737   definition "f x y = x + y + 1"
  1738   definition g where "g x = f x x"
  1739 
  1740   abbreviation
  1741     neq  (infix "=!=" 50) where
  1742     "x =!= y == ~ (x === y)"
  1743 
  1744 These specifications may be also used in a locale context.  Then the
  1745 constants being introduced depend on certain fixed parameters, and the
  1746 constant name is qualified by the locale base name.  An internal
  1747 abbreviation takes care for convenient input and output, making the
  1748 parameters implicit and using the original short name.  See also
  1749 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1750 entities from a monomorphic theory.
  1751 
  1752 Presently, abbreviations are only available 'in' a target locale, but
  1753 not inherited by general import expressions.  Also note that
  1754 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1755 'translations' in common applications.  The "no_abbrevs" print mode
  1756 prevents folding of abbreviations in term output.
  1757 
  1758 Concrete syntax is attached to specified constants in internal form,
  1759 independently of name spaces.  The parse tree representation is
  1760 slightly different -- use 'notation' instead of raw 'syntax', and
  1761 'translations' with explicit "CONST" markup to accommodate this.
  1762 
  1763 * Pure/Isar: unified syntax for new-style specification mechanisms
  1764 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1765 full type inference and dummy patterns ("_").  For example:
  1766 
  1767   definition "K x _ = x"
  1768 
  1769   inductive conj for A B
  1770   where "A ==> B ==> conj A B"
  1771 
  1772 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1773 the current context.  Print mode "no_abbrevs" prevents inversion of
  1774 abbreviations on output.
  1775 
  1776 * Isar/locales: improved parameter handling: use of locales "var" and
  1777 "struct" no longer necessary; - parameter renamings are no longer
  1778 required to be injective.  For example, this allows to define
  1779 endomorphisms as locale endom = homom mult mult h.
  1780 
  1781 * Isar/locales: changed the way locales with predicates are defined.
  1782 Instead of accumulating the specification, the imported expression is
  1783 now an interpretation.  INCOMPATIBILITY: different normal form of
  1784 locale expressions.  In particular, in interpretations of locales with
  1785 predicates, goals repesenting already interpreted fragments are not
  1786 removed automatically.  Use methods `intro_locales' and
  1787 `unfold_locales'; see below.
  1788 
  1789 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1790 provide backward reasoning on locales predicates.  The methods are
  1791 aware of interpretations and discharge corresponding goals.
  1792 `intro_locales' is less aggressive then `unfold_locales' and does not
  1793 unfold predicates to assumptions.
  1794 
  1795 * Isar/locales: the order in which locale fragments are accumulated
  1796 has changed.  This enables to override declarations from fragments due
  1797 to interpretations -- for example, unwanted simp rules.
  1798 
  1799 * Isar/locales: interpretation in theories and proof contexts has been
  1800 extended.  One may now specify (and prove) equations, which are
  1801 unfolded in interpreted theorems.  This is useful for replacing
  1802 defined concepts (constants depending on locale parameters) by
  1803 concepts already existing in the target context.  Example:
  1804 
  1805   interpretation partial_order ["op <= :: [int, int] => bool"]
  1806     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1807 
  1808 Typically, the constant `partial_order.less' is created by a
  1809 definition specification element in the context of locale
  1810 partial_order.
  1811 
  1812 * Method "induct": improved internal context management to support
  1813 local fixes and defines on-the-fly. Thus explicit meta-level
  1814 connectives !!  and ==> are rarely required anymore in inductive goals
  1815 (using object-logic connectives for this purpose has been long
  1816 obsolete anyway). Common proof patterns are explained in
  1817 src/HOL/Induct/Common_Patterns.thy, see also
  1818 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1819 examples.
  1820 
  1821 * Method "induct": improved handling of simultaneous goals. Instead of
  1822 introducing object-level conjunction, the statement is now split into
  1823 several conclusions, while the corresponding symbolic cases are nested
  1824 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1825 see src/HOL/Induct/Common_Patterns.thy, for example.
  1826 
  1827 * Method "induct": mutual induction rules are now specified as a list
  1828 of rule sharing the same induction cases. HOL packages usually provide
  1829 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1830 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1831 mutual induction rules differently, i.e. like this:
  1832 
  1833   (induct rule: foo_bar.inducts)
  1834   (induct set: foo bar)
  1835   (induct pred: foo bar)
  1836   (induct type: foo bar)
  1837 
  1838 The ML function ProjectRule.projections turns old-style rules into the
  1839 new format.
  1840 
  1841 * Method "coinduct": dual of induction, see
  1842 src/HOL/Library/Coinductive_List.thy for various examples.
  1843 
  1844 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1845 considered a legacy feature.
  1846 
  1847 * Attribute "symmetric" produces result with standardized schematic
  1848 variables (index 0).  Potential INCOMPATIBILITY.
  1849 
  1850 * Simplifier: by default the simplifier trace only shows top level
  1851 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1852 default. Thus there is less danger of being flooded by the trace. The
  1853 trace indicates where parts have been suppressed.
  1854   
  1855 * Provers/classical: removed obsolete classical version of elim_format
  1856 attribute; classical elim/dest rules are now treated uniformly when
  1857 manipulating the claset.
  1858 
  1859 * Provers/classical: stricter checks to ensure that supplied intro,
  1860 dest and elim rules are well-formed; dest and elim rules must have at
  1861 least one premise.
  1862 
  1863 * Provers/classical: attributes dest/elim/intro take an optional
  1864 weight argument for the rule (just as the Pure versions).  Weights are
  1865 ignored by automated tools, but determine the search order of single
  1866 rule steps.
  1867 
  1868 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1869 where the body does not mention the bound variable.  Note that dummy
  1870 patterns implicitly depend on their context of bounds, which makes
  1871 "{_. _}" match any set comprehension as expected.  Potential
  1872 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1873 constant "_idtdummy" in the binding position.
  1874 
  1875 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1876 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1877 for example "A -> B" => "Pi A (%_. B)".
  1878 
  1879 * Pure: 'class_deps' command visualizes the subclass relation, using
  1880 the graph browser tool.
  1881 
  1882 * Pure: 'print_theory' now suppresses certain internal declarations by
  1883 default; use '!' option for full details.
  1884 
  1885 
  1886 *** HOL ***
  1887 
  1888 * Method "metis" proves goals by applying the Metis general-purpose
  1889 resolution prover (see also http://gilith.com/software/metis/).
  1890 Examples are in the directory MetisExamples.  WARNING: the
  1891 Isabelle/HOL-Metis integration does not yet work properly with
  1892 multi-threading.
  1893   
  1894 * Command 'sledgehammer' invokes external automatic theorem provers as
  1895 background processes.  It generates calls to the "metis" method if
  1896 successful. These can be pasted into the proof.  Users do not have to
  1897 wait for the automatic provers to return.  WARNING: does not really
  1898 work with multi-threading.
  1899 
  1900 * New "auto_quickcheck" feature tests outermost goal statements for
  1901 potential counter-examples.  Controlled by ML references
  1902 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1903 5000 milliseconds).  Fails silently if statements is outside of
  1904 executable fragment, or any other codgenerator problem occurs.
  1905 
  1906 * New constant "undefined" with axiom "undefined x = undefined".
  1907 
  1908 * Added class "HOL.eq", allowing for code generation with polymorphic
  1909 equality.
  1910 
  1911 * Some renaming of class constants due to canonical name prefixing in
  1912 the new 'class' package:
  1913 
  1914     HOL.abs ~> HOL.abs_class.abs
  1915     HOL.divide ~> HOL.divide_class.divide
  1916     0 ~> HOL.zero_class.zero
  1917     1 ~> HOL.one_class.one
  1918     op + ~> HOL.plus_class.plus
  1919     op - ~> HOL.minus_class.minus
  1920     uminus ~> HOL.minus_class.uminus
  1921     op * ~> HOL.times_class.times
  1922     op < ~> HOL.ord_class.less
  1923     op <= > HOL.ord_class.less_eq
  1924     Nat.power ~> Power.power_class.power
  1925     Nat.size ~> Nat.size_class.size
  1926     Numeral.number_of ~> Numeral.number_class.number_of
  1927     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1928     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1929     Orderings.min ~> Orderings.ord_class.min
  1930     Orderings.max ~> Orderings.ord_class.max
  1931     Divides.op div ~> Divides.div_class.div
  1932     Divides.op mod ~> Divides.div_class.mod
  1933     Divides.op dvd ~> Divides.div_class.dvd
  1934 
  1935 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1936 
  1937 a) User-defined constants using any of the names "plus", "minus",
  1938 "times", "less" or "less_eq". The standard syntax translations for
  1939 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1940 names.
  1941 
  1942 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1943 INCOMPATIBILITY: use more specific names.
  1944 
  1945 c) Permutative equations (e.g. "a + b = b + a")
  1946 Since the change of names also changes the order of terms, permutative
  1947 rewrite rules may get applied in a different order. Experience shows
  1948 that this is rarely the case (only two adaptions in the whole Isabelle
  1949 distribution).  INCOMPATIBILITY: rewrite proofs
  1950 
  1951 d) ML code directly refering to constant names
  1952 This in general only affects hand-written proof tactics, simprocs and
  1953 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1954 Consider using @{const_name} antiquotation.
  1955 
  1956 * New class "default" with associated constant "default".
  1957 
  1958 * Function "sgn" is now overloaded and available on int, real, complex
  1959 (and other numeric types), using class "sgn".  Two possible defs of
  1960 sgn are given as equational assumptions in the classes sgn_if and
  1961 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1962 INCOMPATIBILITY.
  1963 
  1964 * Locale "partial_order" now unified with class "order" (cf. theory
  1965 Orderings), added parameter "less".  INCOMPATIBILITY.
  1966 
  1967 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1968 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1969 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1970 
  1971 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1972 changed order of proof goals in instance proofs.
  1973 
  1974 * The transitivity reasoner for partial and linear orders is set up
  1975 for classes "order" and "linorder".  Instances of the reasoner are available
  1976 in all contexts importing or interpreting the corresponding locales.
  1977 Method "order" invokes the reasoner separately; the reasoner
  1978 is also integrated with the Simplifier as a solver.  Diagnostic
  1979 command 'print_orders' shows the available instances of the reasoner
  1980 in the current context.
  1981 
  1982 * Localized monotonicity predicate in theory "Orderings"; integrated
  1983 lemmas max_of_mono and min_of_mono with this predicate.
  1984 INCOMPATIBILITY.
  1985 
  1986 * Formulation of theorem "dense" changed slightly due to integration
  1987 with new class dense_linear_order.
  1988 
  1989 * Uniform lattice theory development in HOL.
  1990 
  1991     constants "meet" and "join" now named "inf" and "sup"
  1992     constant "Meet" now named "Inf"
  1993 
  1994     classes "meet_semilorder" and "join_semilorder" now named
  1995       "lower_semilattice" and "upper_semilattice"
  1996     class "lorder" now named "lattice"
  1997     class "comp_lat" now named "complete_lattice"
  1998 
  1999     Instantiation of lattice classes allows explicit definitions
  2000     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  2001 
  2002   INCOMPATIBILITY.  Theorem renames:
  2003 
  2004     meet_left_le            ~> inf_le1
  2005     meet_right_le           ~> inf_le2
  2006     join_left_le            ~> sup_ge1
  2007     join_right_le           ~> sup_ge2
  2008     meet_join_le            ~> inf_sup_ord
  2009     le_meetI                ~> le_infI
  2010     join_leI                ~> le_supI
  2011     le_meet                 ~> le_inf_iff
  2012     le_join                 ~> ge_sup_conv
  2013     meet_idempotent         ~> inf_idem
  2014     join_idempotent         ~> sup_idem
  2015     meet_comm               ~> inf_commute
  2016     join_comm               ~> sup_commute
  2017     meet_leI1               ~> le_infI1
  2018     meet_leI2               ~> le_infI2
  2019     le_joinI1               ~> le_supI1
  2020     le_joinI2               ~> le_supI2
  2021     meet_assoc              ~> inf_assoc
  2022     join_assoc              ~> sup_assoc
  2023     meet_left_comm          ~> inf_left_commute
  2024     meet_left_idempotent    ~> inf_left_idem
  2025     join_left_comm          ~> sup_left_commute
  2026     join_left_idempotent    ~> sup_left_idem
  2027     meet_aci                ~> inf_aci
  2028     join_aci                ~> sup_aci
  2029     le_def_meet             ~> le_iff_inf
  2030     le_def_join             ~> le_iff_sup
  2031     join_absorp2            ~> sup_absorb2
  2032     join_absorp1            ~> sup_absorb1
  2033     meet_absorp1            ~> inf_absorb1
  2034     meet_absorp2            ~> inf_absorb2
  2035     meet_join_absorp        ~> inf_sup_absorb
  2036     join_meet_absorp        ~> sup_inf_absorb
  2037     distrib_join_le         ~> distrib_sup_le
  2038     distrib_meet_le         ~> distrib_inf_le
  2039 
  2040     add_meet_distrib_left   ~> add_inf_distrib_left
  2041     add_join_distrib_left   ~> add_sup_distrib_left
  2042     is_join_neg_meet        ~> is_join_neg_inf
  2043     is_meet_neg_join        ~> is_meet_neg_sup
  2044     add_meet_distrib_right  ~> add_inf_distrib_right
  2045     add_join_distrib_right  ~> add_sup_distrib_right
  2046     add_meet_join_distribs  ~> add_sup_inf_distribs
  2047     join_eq_neg_meet        ~> sup_eq_neg_inf
  2048     meet_eq_neg_join        ~> inf_eq_neg_sup
  2049     add_eq_meet_join        ~> add_eq_inf_sup
  2050     meet_0_imp_0            ~> inf_0_imp_0
  2051     join_0_imp_0            ~> sup_0_imp_0
  2052     meet_0_eq_0             ~> inf_0_eq_0
  2053     join_0_eq_0             ~> sup_0_eq_0
  2054     neg_meet_eq_join        ~> neg_inf_eq_sup
  2055     neg_join_eq_meet        ~> neg_sup_eq_inf
  2056     join_eq_if              ~> sup_eq_if
  2057 
  2058     mono_meet               ~> mono_inf
  2059     mono_join               ~> mono_sup
  2060     meet_bool_eq            ~> inf_bool_eq
  2061     join_bool_eq            ~> sup_bool_eq
  2062     meet_fun_eq             ~> inf_fun_eq
  2063     join_fun_eq             ~> sup_fun_eq
  2064     meet_set_eq             ~> inf_set_eq
  2065     join_set_eq             ~> sup_set_eq
  2066     meet1_iff               ~> inf1_iff
  2067     meet2_iff               ~> inf2_iff
  2068     meet1I                  ~> inf1I
  2069     meet2I                  ~> inf2I
  2070     meet1D1                 ~> inf1D1
  2071     meet2D1                 ~> inf2D1
  2072     meet1D2                 ~> inf1D2
  2073     meet2D2                 ~> inf2D2
  2074     meet1E                  ~> inf1E
  2075     meet2E                  ~> inf2E
  2076     join1_iff               ~> sup1_iff
  2077     join2_iff               ~> sup2_iff
  2078     join1I1                 ~> sup1I1
  2079     join2I1                 ~> sup2I1
  2080     join1I1                 ~> sup1I1
  2081     join2I2                 ~> sup1I2
  2082     join1CI                 ~> sup1CI
  2083     join2CI                 ~> sup2CI
  2084     join1E                  ~> sup1E
  2085     join2E                  ~> sup2E
  2086 
  2087     is_meet_Meet            ~> is_meet_Inf
  2088     Meet_bool_def           ~> Inf_bool_def
  2089     Meet_fun_def            ~> Inf_fun_def
  2090     Meet_greatest           ~> Inf_greatest
  2091     Meet_lower              ~> Inf_lower
  2092     Meet_set_def            ~> Inf_set_def
  2093 
  2094     Sup_def                 ~> Sup_Inf
  2095     Sup_bool_eq             ~> Sup_bool_def
  2096     Sup_fun_eq              ~> Sup_fun_def
  2097     Sup_set_eq              ~> Sup_set_def
  2098 
  2099     listsp_meetI            ~> listsp_infI
  2100     listsp_meet_eq          ~> listsp_inf_eq
  2101 
  2102     meet_min                ~> inf_min
  2103     join_max                ~> sup_max
  2104 
  2105 * Added syntactic class "size"; overloaded constant "size" now has
  2106 type "'a::size ==> bool"
  2107 
  2108 * Internal reorganisation of `size' of datatypes: size theorems
  2109 "foo.size" are no longer subsumed by "foo.simps" (but are still
  2110 simplification rules by default!); theorems "prod.size" now named
  2111 "*.size".
  2112 
  2113 * Class "div" now inherits from class "times" rather than "type".
  2114 INCOMPATIBILITY.
  2115 
  2116 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  2117 Linorder etc.  have disappeared; operations defined in terms of
  2118 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  2119 
  2120 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  2121 
  2122 * HOL-Word: New extensive library and type for generic, fixed size
  2123 machine words, with arithemtic, bit-wise, shifting and rotating
  2124 operations, reflection into int, nat, and bool lists, automation for
  2125 linear arithmetic (by automatic reflection into nat or int), including
  2126 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  2127 arithmetic type classes, supporting automatic simplification of
  2128 numerals on all operations.
  2129 
  2130 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  2131 
  2132 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  2133 
  2134 * Code generator library theories:
  2135   - Code_Integer represents HOL integers by big integer literals in target
  2136     languages.
  2137   - Code_Char represents HOL characters by character literals in target
  2138     languages.
  2139   - Code_Char_chr like Code_Char, but also offers treatment of character
  2140     codes; includes Code_Integer.
  2141   - Executable_Set allows to generate code for finite sets using lists.
  2142   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  2143     denominator).
  2144   - Executable_Real implements a subset of real numbers, namly those
  2145     representable by rational numbers.
  2146   - Efficient_Nat implements natural numbers by integers, which in general will
  2147     result in higher efficency; pattern matching with 0/Suc is eliminated;
  2148     includes Code_Integer.
  2149   - Code_Index provides an additional datatype index which is mapped to
  2150     target-language built-in integers.
  2151   - Code_Message provides an additional datatype message_string which is isomorphic to
  2152     strings; messages are mapped to target-language strings.
  2153 
  2154 * New package for inductive predicates
  2155 
  2156   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  2157 
  2158     inductive
  2159       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2160       for z_1 :: U_1 and ... and z_n :: U_m
  2161     where
  2162       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2163     | ...
  2164 
  2165   with full support for type-inference, rather than
  2166 
  2167     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2168 
  2169     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2170     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2171 
  2172     inductive "s z_1 ... z_m"
  2173     intros
  2174       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2175       ...
  2176 
  2177   For backward compatibility, there is a wrapper allowing inductive
  2178   sets to be defined with the new package via
  2179 
  2180     inductive_set
  2181       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2182       for z_1 :: U_1 and ... and z_n :: U_m
  2183     where
  2184       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  2185     | ...
  2186 
  2187   or
  2188 
  2189     inductive_set
  2190       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  2191       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  2192       for z_1 :: U_1 and ... and z_n :: U_m
  2193     where
  2194       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  2195     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  2196     | ...
  2197 
  2198   if the additional syntax "p ..." is required.
  2199 
  2200   Numerous examples can be found in the subdirectories src/HOL/Auth,
  2201   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  2202 
  2203   INCOMPATIBILITIES:
  2204 
  2205   - Since declaration and definition of inductive sets or predicates
  2206     is no longer separated, abbreviations involving the newly
  2207     introduced sets or predicates must be specified together with the
  2208     introduction rules after the 'where' keyword (see above), rather
  2209     than before the actual inductive definition.
  2210 
  2211   - The variables in induction and elimination rules are now
  2212     quantified in the order of their occurrence in the introduction
  2213     rules, rather than in alphabetical order. Since this may break
  2214     some proofs, these proofs either have to be repaired, e.g. by
  2215     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  2216     statements of the form
  2217 
  2218       case (rule_i a_i_1 ... a_i_{k_i})
  2219 
  2220     or the old order of quantification has to be restored by explicitly adding
  2221     meta-level quantifiers in the introduction rules, i.e.
  2222 
  2223       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  2224 
  2225   - The format of the elimination rules is now
  2226 
  2227       p z_1 ... z_m x_1 ... x_n ==>
  2228         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2229         ==> ... ==> P
  2230 
  2231     for predicates and
  2232 
  2233       (x_1, ..., x_n) : s z_1 ... z_m ==>
  2234         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  2235         ==> ... ==> P
  2236 
  2237     for sets rather than
  2238 
  2239       x : s z_1 ... z_m ==>
  2240         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  2241         ==> ... ==> P
  2242 
  2243     This may require terms in goals to be expanded to n-tuples
  2244     (e.g. using case_tac or simplification with the split_paired_all
  2245     rule) before the above elimination rule is applicable.
  2246 
  2247   - The elimination or case analysis rules for (mutually) inductive
  2248     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  2249     list of rules "p_1_..._p_k.elims" is no longer available.
  2250 
  2251 * New package "function"/"fun" for general recursive functions,
  2252 supporting mutual and nested recursion, definitions in local contexts,
  2253 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  2254 for small examples, and the separate tutorial on the function
  2255 package. The old recdef "package" is still available as before, but
  2256 users are encouraged to use the new package.
  2257 
  2258 * Method "lexicographic_order" automatically synthesizes termination
  2259 relations as lexicographic combinations of size measures. 
  2260 
  2261 * Case-expressions allow arbitrary constructor-patterns (including
  2262 "_") and take their order into account, like in functional
  2263 programming.  Internally, this is translated into nested
  2264 case-expressions; missing cases are added and mapped to the predefined
  2265 constant "undefined". In complicated cases printing may no longer show
  2266 the original input but the internal form. Lambda-abstractions allow
  2267 the same form of pattern matching: "% pat1 => e1 | ..." is an
  2268 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  2269 variable.
  2270 
  2271 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  2272 is an abbreviation for "of_nat :: nat => int". The simplification
  2273 rules for "of_nat" have been changed to work like "int" did
  2274 previously.  Potential INCOMPATIBILITY:
  2275   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  2276   - of_nat_diff and of_nat_mult are no longer default simp rules
  2277 
  2278 * Method "algebra" solves polynomial equations over (semi)rings using
  2279 Groebner bases. The (semi)ring structure is defined by locales and the
  2280 tool setup depends on that generic context. Installing the method for
  2281 a specific type involves instantiating the locale and possibly adding
  2282 declarations for computation on the coefficients.  The method is
  2283 already instantiated for natural numbers and for the axiomatic class
  2284 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  2285 CALCULEMUS 2007 for the general principles underlying this
  2286 architecture of context-aware proof-tools.
  2287 
  2288 * Method "ferrack" implements quantifier elimination over
  2289 special-purpose dense linear orders using locales (analogous to
  2290 "algebra"). The method is already installed for class
  2291 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  2292 rat, etc.
  2293 
  2294 * Former constant "List.op @" now named "List.append".  Use ML
  2295 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  2296 circumvent possible incompatibilities when working on ML level.
  2297 
  2298 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  2299 
  2300 * New function listsum :: 'a list => 'a for arbitrary monoids.
  2301 Special syntax: "SUM x <- xs. f x" (and latex variants)
  2302 
  2303 * New syntax for Haskell-like list comprehension (input only), eg.
  2304 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  2305 
  2306 * The special syntax for function "filter" has changed from [x :
  2307 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  2308 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  2309 
  2310 * [a..b] is now defined for arbitrary linear orders.  It used to be
  2311 defined on nat only, as an abbreviation for [a..<Suc b]
  2312 INCOMPATIBILITY.
  2313 
  2314 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  2315 
  2316 * New functions "sorted" and "sort" in src/HOL/List.thy.
  2317 
  2318 * New lemma collection field_simps (an extension of ring_simps) for
  2319 manipulating (in)equations involving division. Multiplies with all
  2320 denominators that can be proved to be non-zero (in equations) or
  2321 positive/negative (in inequations).
  2322 
  2323 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  2324 have been improved and renamed to ring_simps, group_simps and
  2325 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  2326 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  2327 
  2328 * Theory Library/Commutative_Ring: switched from recdef to function
  2329 package; constants add, mul, pow now curried.  Infix syntax for
  2330 algebraic operations.
  2331 
  2332 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  2333 INCOMPATIBILITY.
  2334 
  2335 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  2336 INCOMPATIBILITY.
  2337 
  2338 * HOL/records: generalised field-update to take a function on the
  2339 field rather than the new value: r(|A := x|) is translated to A_update
  2340 (K x) r The K-combinator that is internally used is called K_record.
  2341 INCOMPATIBILITY: Usage of the plain update functions has to be
  2342 adapted.
  2343  
  2344 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  2345 * x = 0, which are required for a semiring.  Richer structures do not
  2346 inherit from semiring_0 anymore, because this property is a theorem
  2347 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  2348 there is more to prove, but this is mostly trivial.
  2349 
  2350 * Class "recpower" is generalized to arbitrary monoids, not just
  2351 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  2352 commutativity or semiring properties additionally.
  2353 
  2354 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  2355 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  2356 better use 'abbreviation'.
  2357 
  2358 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  2359 
  2360 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  2361 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  2362 significant changes for setting up numeral syntax for types:
  2363   - New constants Numeral.pred and Numeral.succ instead
  2364       of former Numeral.bin_pred and Numeral.bin_succ.
  2365   - Use integer operations instead of bin_add, bin_mult and so on.
  2366   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  2367   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  2368 
  2369 See src/HOL/Integ/IntArith.thy for an example setup.
  2370 
  2371 * Command 'normal_form' computes the normal form of a term that may
  2372 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  2373 produces ``[b, c, a]'' (without proof).  This command is suitable for
  2374 heavy-duty computations because the functions are compiled to ML
  2375 first.  Correspondingly, a method "normalization" is provided.  See
  2376 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  2377 
  2378 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  2379 25 like -->); output depends on the "iff" print_mode, the default is
  2380 "A = B" (with priority 50).
  2381 
  2382 * Relations less (<) and less_eq (<=) are also available on type bool.
  2383 Modified syntax to disallow nesting without explicit parentheses,
  2384 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  2385 INCOMPATIBILITY.
  2386 
  2387 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  2388 
  2389 * Relation composition operator "op O" now has precedence 75 and binds
  2390 stronger than union and intersection. INCOMPATIBILITY.
  2391 
  2392 * The old set interval syntax "{m..n(}" (and relatives) has been
  2393 removed.  Use "{m..<n}" (and relatives) instead.
  2394 
  2395 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  2396 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  2397 ``declare [[simproc del: neq]]''.
  2398 
  2399 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  2400 True/False.
  2401 
  2402 * Theorem Cons_eq_map_conv no longer declared as "simp".
  2403 
  2404 * Theorem setsum_mult renamed to setsum_right_distrib.
  2405 
  2406 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  2407 ``rule'' method.
  2408 
  2409 * Reimplemented methods "sat" and "satx", with several improvements:
  2410 goals no longer need to be stated as "<prems> ==> False", equivalences
  2411 (i.e. "=" on type bool) are handled, variable names of the form
  2412 "lit_<n>" are no longer reserved, significant speedup.
  2413 
  2414 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  2415 zChaff is still supported as well.
  2416 
  2417 * 'inductive' and 'datatype': provide projections of mutual rules,
  2418 bundled as foo_bar.inducts;
  2419 
  2420 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  2421 Library.
  2422 
  2423 * Library: moved theory Accessible_Part to main HOL.
  2424 
  2425 * Library: added theory Coinductive_List of potentially infinite lists
  2426 as greatest fixed-point.
  2427 
  2428 * Library: added theory AssocList which implements (finite) maps as
  2429 association lists.
  2430 
  2431 * Method "evaluation" solves goals (i.e. a boolean expression)
  2432 efficiently by compiling it to ML.  The goal is "proved" (via an
  2433 oracle) if it evaluates to True.
  2434 
  2435 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  2436 also when invoked by the simplifier.  This results in the Simplifier
  2437 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  2438 Configuration option fast_arith_split_limit=0 recovers the old
  2439 behavior.
  2440 
  2441 * Support for hex (0x20) and binary (0b1001) numerals.
  2442 
  2443 * New method: reify eqs (t), where eqs are equations for an
  2444 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  2445 parameter, computes a term s::'b and a list xs::'a list and proves the
  2446 theorem I xs s = t. This is also known as reification or quoting. The
  2447 resulting theorem is applied to the subgoal to substitute t with I xs
  2448 s.  If t is omitted, the subgoal itself is reified.
  2449 
  2450 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  2451 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  2452 where f is supposed to be a computable function (in the sense of code
  2453 generattion). The method uses reify to compute s and xs as above then
  2454 applies corr_thm and uses normalization by evaluation to "prove" f s =
  2455 r and finally gets the theorem t = r, which is again applied to the
  2456 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  2457 
  2458 * Reflection: Automatic reification now handels binding, an example is
  2459 available in src/HOL/ex/ReflectionEx.thy
  2460 
  2461 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  2462 command 'statespace' that is similar to 'record', but introduces an
  2463 abstract specification based on the locale infrastructure instead of
  2464 HOL types.  This leads to extra flexibility in composing state spaces,
  2465 in particular multiple inheritance and renaming of components.
  2466 
  2467 
  2468 *** HOL-Complex ***
  2469 
  2470 * Hyperreal: Functions root and sqrt are now defined on negative real
  2471 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  2472 Nonnegativity side conditions have been removed from many lemmas, so
  2473 that more subgoals may now be solved by simplification; potential
  2474 INCOMPATIBILITY.
  2475 
  2476 * Real: new type classes formalize real normed vector spaces and
  2477 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  2478 and norm :: 'a => real.
  2479 
  2480 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  2481 reals into other types. The overloaded constant Reals :: 'a set is now
  2482 defined as range of_real; potential INCOMPATIBILITY.
  2483 
  2484 * Real: proper support for ML code generation, including 'quickcheck'.
  2485 Reals are implemented as arbitrary precision rationals.
  2486 
  2487 * Hyperreal: Several constants that previously worked only for the
  2488 reals have been generalized, so they now work over arbitrary vector
  2489 spaces. Type annotations may need to be added in some cases; potential
  2490 INCOMPATIBILITY.
  2491 
  2492   Infinitesimal  :: ('a::real_normed_vector) star set
  2493   HFinite        :: ('a::real_normed_vector) star set
  2494   HInfinite      :: ('a::real_normed_vector) star set
  2495   approx         :: ('a::real_normed_vector) star => 'a star => bool
  2496   monad          :: ('a::real_normed_vector) star => 'a star set
  2497   galaxy         :: ('a::real_normed_vector) star => 'a star set
  2498   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  2499   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  2500   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  2501   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  2502   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  2503   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  2504   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  2505   sgn            :: 'a::real_normed_vector => 'a
  2506   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  2507 
  2508 * Complex: Some complex-specific constants are now abbreviations for
  2509 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  2510 hnorm.  Other constants have been entirely removed in favor of the
  2511 polymorphic versions (INCOMPATIBILITY):
  2512 
  2513   approx        <-- capprox
  2514   HFinite       <-- CFinite
  2515   HInfinite     <-- CInfinite
  2516   Infinitesimal <-- CInfinitesimal
  2517   monad         <-- cmonad
  2518   galaxy        <-- cgalaxy
  2519   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  2520   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  2521   (ns)deriv     <-- (ns)cderiv
  2522 
  2523 
  2524 *** HOL-Algebra ***
  2525 
  2526 * Formalisation of ideals and the quotient construction over rings.
  2527 
  2528 * Order and lattice theory no longer based on records.
  2529 INCOMPATIBILITY.
  2530 
  2531 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  2532 greatest_closed.  INCOMPATIBILITY.
  2533 
  2534 * Method algebra is now set up via an attribute.  For examples see
  2535 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  2536 of algebraic structures.
  2537 
  2538 * Renamed theory CRing to Ring.
  2539 
  2540 
  2541 *** HOL-Nominal ***
  2542 
  2543 * Substantial, yet incomplete support for nominal datatypes (binding
  2544 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  2545 src/HOL/Nominal/Examples.  Prospective users should consult
  2546 http://isabelle.in.tum.de/nominal/
  2547 
  2548 
  2549 *** ML ***
  2550 
  2551 * ML basics: just one true type int, which coincides with IntInf.int
  2552 (even on SML/NJ).
  2553 
  2554 * ML within Isar: antiquotations allow to embed statically-checked
  2555 formal entities in the source, referring to the context available at
  2556 compile-time.  For example:
  2557 
  2558 ML {* @{sort "{zero,one}"} *}
  2559 ML {* @{typ "'a => 'b"} *}
  2560 ML {* @{term "%x. x"} *}
  2561 ML {* @{prop "x == y"} *}
  2562 ML {* @{ctyp "'a => 'b"} *}
  2563 ML {* @{cterm "%x. x"} *}
  2564 ML {* @{cprop "x == y"} *}
  2565 ML {* @{thm asm_rl} *}
  2566 ML {* @{thms asm_rl} *}
  2567 ML {* @{type_name c} *}
  2568 ML {* @{type_syntax c} *}
  2569 ML {* @{const_name c} *}
  2570 ML {* @{const_syntax c} *}
  2571 ML {* @{context} *}
  2572 ML {* @{theory} *}
  2573 ML {* @{theory Pure} *}
  2574 ML {* @{theory_ref} *}
  2575 ML {* @{theory_ref Pure} *}
  2576 ML {* @{simpset} *}
  2577 ML {* @{claset} *}
  2578 ML {* @{clasimpset} *}
  2579 
  2580 The same works for sources being ``used'' within an Isar context.
  2581 
  2582 * ML in Isar: improved error reporting; extra verbosity with
  2583 ML_Context.trace enabled.
  2584 
  2585 * Pure/General/table.ML: the join operations now works via exceptions
  2586 DUP/SAME instead of type option. This is simpler in simple cases, and
  2587 admits slightly more efficient complex applications.
  2588 
  2589 * Pure: 'advanced' translation functions (parse_translation etc.) now
  2590 use Context.generic instead of just theory.
  2591 
  2592 * Pure: datatype Context.generic joins theory/Proof.context and
  2593 provides some facilities for code that works in either kind of
  2594 context, notably GenericDataFun for uniform theory and proof data.
  2595 
  2596 * Pure: simplified internal attribute type, which is now always
  2597 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  2598 local (Proof.context) attributes have been discontinued, while
  2599 minimizing code duplication. Thm.rule_attribute and
  2600 Thm.declaration_attribute build canonical attributes; see also structure
  2601 Context for further operations on Context.generic, notably
  2602 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  2603 declarations and definitions.
  2604 
  2605 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  2606 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  2607 init only required for impure data. INCOMPATIBILITY: empty really need
  2608 to be empty (no dependencies on theory content!)
  2609 
  2610 * Pure/kernel: consts certification ignores sort constraints given in
  2611 signature declarations. (This information is not relevant to the
  2612 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  2613 potential INCOMPATIBILITY.
  2614 
  2615 * Pure: axiomatic type classes are now purely definitional, with
  2616 explicit proofs of class axioms and super class relations performed
  2617 internally. See Pure/axclass.ML for the main internal interfaces --
  2618 notably AxClass.define_class supercedes AxClass.add_axclass, and
  2619 AxClass.axiomatize_class/classrel/arity supersede
  2620 Sign.add_classes/classrel/arities.
  2621 
  2622 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  2623 global/local versions on theory vs. Proof.context have been
  2624 discontinued; Attrib.syntax and Method.syntax have been adapted
  2625 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  2626 attributes, methods, etc.
  2627 
  2628 * Pure: several functions of signature "... -> theory -> theory * ..."
  2629 have been reoriented to "... -> theory -> ... * theory" in order to
  2630 allow natural usage in combination with the ||>, ||>>, |-> and
  2631 fold_map combinators.
  2632 
  2633 * Pure: official theorem names (closed derivations) and additional
  2634 comments (tags) are now strictly separate.  Name hints -- which are
  2635 maintained as tags -- may be attached any time without affecting the
  2636 derivation.
  2637 
  2638 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  2639 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  2640 achieve the old behaviour.
  2641 
  2642 * Pure: the "Goal" constant is now called "prop", supporting a
  2643 slightly more general idea of ``protecting'' meta-level rule
  2644 statements.
  2645 
  2646 * Pure: Logic.(un)varify only works in a global context, which is now
  2647 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  2648 Logic.legacy_(un)varify as temporary workaround.
  2649 
  2650 * Pure: structure Name provides scalable operations for generating
  2651 internal variable names, notably Name.variants etc.  This replaces
  2652 some popular functions from term.ML:
  2653 
  2654   Term.variant		->  Name.variant
  2655   Term.variantlist	->  Name.variant_list
  2656   Term.invent_names	->  Name.invent_list
  2657 
  2658 Note that low-level renaming rarely occurs in new code -- operations
  2659 from structure Variable are used instead (see below).
  2660 
  2661 * Pure: structure Variable provides fundamental operations for proper
  2662 treatment of fixed/schematic variables in a context.  For example,
  2663 Variable.import introduces fixes for schematics of given facts and
  2664 Variable.export reverses the effect (up to renaming) -- this replaces
  2665 various freeze_thaw operations.
  2666 
  2667 * Pure: structure Goal provides simple interfaces for
  2668 init/conclude/finish and tactical prove operations (replacing former
  2669 Tactic.prove).  Goal.prove is the canonical way to prove results
  2670 within a given context; Goal.prove_global is a degraded version for
  2671 theory level goals, including a global Drule.standard.  Note that
  2672 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2673 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2674 in a locale context).
  2675 
  2676 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2677 and type checking (Syntax.check_term etc.), with common combinations
  2678 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2679 which are considered legacy and await removal.
  2680 
  2681 * Pure/Syntax: generic interfaces for type unchecking
  2682 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2683 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2684 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2685 available for convenience, but refer to the very same operations using
  2686 a mere theory instead of a full context.
  2687 
  2688 * Isar: simplified treatment of user-level errors, using exception
  2689 ERROR of string uniformly.  Function error now merely raises ERROR,
  2690 without any side effect on output channels.  The Isar toplevel takes
  2691 care of proper display of ERROR exceptions.  ML code may use plain
  2692 handle/can/try; cat_error may be used to concatenate errors like this:
  2693 
  2694   ... handle ERROR msg => cat_error msg "..."
  2695 
  2696 Toplevel ML code (run directly or through the Isar toplevel) may be
  2697 embedded into the Isar toplevel with exception display/debug like
  2698 this:
  2699 
  2700   Isar.toplevel (fn () => ...)
  2701 
  2702 INCOMPATIBILITY, removed special transform_error facilities, removed
  2703 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2704 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2705 -- use plain ERROR instead.
  2706 
  2707 * Isar: theory setup now has type (theory -> theory), instead of a
  2708 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2709 
  2710 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2711 ProofContext.debug/verbose flags.
  2712 
  2713 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2714 theory before entering a proof state.  Transactions now always see a
  2715 quasi-functional intermediate checkpoint, both in interactive and
  2716 batch mode.
  2717 
  2718 * Isar: simplified interfaces for outer syntax.  Renamed
  2719 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2720 OuterSyntax.add_parsers -- this functionality is now included in
  2721 OuterSyntax.command etc.  INCOMPATIBILITY.
  2722 
  2723 * Simplifier: the simpset of a running simplification process now
  2724 contains a proof context (cf. Simplifier.the_context), which is the
  2725 very context that the initial simpset has been retrieved from (by
  2726 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2727 (solver, looper etc.) may depend on arbitrary proof data.
  2728 
  2729 * Simplifier.inherit_context inherits the proof context (plus the
  2730 local bounds) of the current simplification process; any simproc
  2731 etc. that calls the Simplifier recursively should do this!  Removed
  2732 former Simplifier.inherit_bounds, which is already included here --
  2733 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2734 specify an explicit context using Simplifier.context/theory_context.
  2735 
  2736 * Simplifier/Classical Reasoner: more abstract interfaces
  2737 change_simpset/claset for modifying the simpset/claset reference of a
  2738 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2739 INCOMPATIBILITY.
  2740 
  2741 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2742 "Trueprop" etc.
  2743 
  2744 
  2745 *** System ***
  2746 
  2747 * settings: the default heap location within ISABELLE_HOME_USER now
  2748 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2749 Isabelle installations.
  2750 
  2751 * isabelle-process: option -S (secure mode) disables some critical
  2752 operations, notably runtime compilation and evaluation of ML source
  2753 code.
  2754 
  2755 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2756 
  2757 * Support for parallel execution, using native multicore support of
  2758 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2759 independent theories, according to the given theory header
  2760 specifications. The maximum number of worker threads is specified via
  2761 usedir option -M or the "max-threads" setting in Proof General. A
  2762 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2763 to 6 on a 8-core machine.  User-code needs to observe certain
  2764 guidelines for thread-safe programming, see appendix A in the Isar
  2765 Implementation manual.
  2766 
  2767 
  2768 
  2769 New in Isabelle2005 (October 2005)
  2770 ----------------------------------
  2771 
  2772 *** General ***
  2773 
  2774 * Theory headers: the new header syntax for Isar theories is
  2775 
  2776   theory <name>
  2777   imports <theory1> ... <theoryN>
  2778   uses <file1> ... <fileM>
  2779   begin
  2780 
  2781 where the 'uses' part is optional.  The previous syntax
  2782 
  2783   theory <name> = <theory1> + ... + <theoryN>:
  2784 
  2785 will disappear in the next release.  Use isatool fixheaders to convert
  2786 existing theory files.  Note that there is no change in ancient
  2787 non-Isar theories now, but these will disappear soon.
  2788 
  2789 * Theory loader: parent theories can now also be referred to via
  2790 relative and absolute paths.
  2791 
  2792 * Command 'find_theorems' searches for a list of criteria instead of a
  2793 list of constants. Known criteria are: intro, elim, dest, name:string,
  2794 simp:term, and any term. Criteria can be preceded by '-' to select
  2795 theorems that do not match. Intro, elim, dest select theorems that
  2796 match the current goal, name:s selects theorems whose fully qualified
  2797 name contain s, and simp:term selects all simplification rules whose
  2798 lhs match term.  Any other term is interpreted as pattern and selects
  2799 all theorems matching the pattern. Available in ProofGeneral under
  2800 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2801 
  2802   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2803 
  2804 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2805 matching the current goal as introduction rule and not having "HOL."
  2806 in their name (i.e. not being defined in theory HOL).
  2807 
  2808 * Command 'thms_containing' has been discontinued in favour of
  2809 'find_theorems'; INCOMPATIBILITY.
  2810 
  2811 * Communication with Proof General is now 8bit clean, which means that
  2812 Unicode text in UTF-8 encoding may be used within theory texts (both
  2813 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2814 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2815 
  2816   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2817   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2818 
  2819 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2820 Classical Reasoner.  Typical big applications run around 2 times
  2821 faster.
  2822 
  2823 
  2824 *** Document preparation ***
  2825 
  2826 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2827 of raw sources.  Only those symbols that do not require additional
  2828 LaTeX packages (depending on comments in isabellesym.sty) are
  2829 displayed properly, everything else is left verbatim.  isatool display
  2830 and isatool print are used as front ends (these are subject to the
  2831 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2832 
  2833 * Command tags control specific markup of certain regions of text,
  2834 notably folding and hiding.  Predefined tags include "theory" (for
  2835 theory begin and end), "proof" for proof commands, and "ML" for
  2836 commands involving ML code; the additional tags "visible" and
  2837 "invisible" are unused by default.  Users may give explicit tag
  2838 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2839 interpretation of tags is determined by the LaTeX job during document
  2840 preparation: see option -V of isatool usedir, or options -n and -t of
  2841 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2842 \isadroptag.
  2843 
  2844 Several document versions may be produced at the same time via isatool
  2845 usedir (the generated index.html will link all of them).  Typical
  2846 specifications include ''-V document=theory,proof,ML'' to present
  2847 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2848 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2849 these parts without any formal replacement text.  The Isabelle site
  2850 default settings produce ''document'' and ''outline'' versions as
  2851 specified above.
  2852 
  2853 * Several new antiquotations:
  2854 
  2855   @{term_type term} prints a term with its type annotated;
  2856 
  2857   @{typeof term} prints the type of a term;
  2858 
  2859   @{const const} is the same as @{term const}, but checks that the
  2860   argument is a known logical constant;
  2861 
  2862   @{term_style style term} and @{thm_style style thm} print a term or
  2863   theorem applying a "style" to it
  2864 
  2865   @{ML text}
  2866 
  2867 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2868 definitions, equations, inequations etc., 'concl' printing only the
  2869 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2870 to print the specified premise.  TermStyle.add_style provides an ML
  2871 interface for introducing further styles.  See also the "LaTeX Sugar"
  2872 document practical applications.  The ML antiquotation prints
  2873 type-checked ML expressions verbatim.
  2874 
  2875 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2876 and 'text' support optional locale specification '(in loc)', which
  2877 specifies the default context for interpreting antiquotations.  For
  2878 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2879 
  2880 * Option 'locale=NAME' of antiquotations specifies an alternative
  2881 context interpreting the subsequent argument.  For example: @{thm
  2882 [locale=lattice] inf_assoc}.
  2883 
  2884 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2885 a proof context.
  2886 
  2887 * Proper output of antiquotations for theory commands involving a
  2888 proof context (such as 'locale' or 'theorem (in loc) ...').
  2889 
  2890 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2891 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2892 
  2893 * isatool usedir: new option -C (default true) controls whether option
  2894 -D should include a copy of the original document directory; -C false
  2895 prevents unwanted effects such as copying of administrative CVS data.
  2896 
  2897 
  2898 *** Pure ***
  2899 
  2900 * Considerably improved version of 'constdefs' command.  Now performs
  2901 automatic type-inference of declared constants; additional support for
  2902 local structure declarations (cf. locales and HOL records), see also
  2903 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2904 sequential dependencies of definitions within a single 'constdefs'
  2905 section; moreover, the declared name needs to be an identifier.  If
  2906 all fails, consider to fall back on 'consts' and 'defs' separately.
  2907 
  2908 * Improved indexed syntax and implicit structures.  First of all,
  2909 indexed syntax provides a notational device for subscripted
  2910 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2911 expressions.  Secondly, in a local context with structure
  2912 declarations, number indexes \<^sub>n or the empty index (default
  2913 number 1) refer to a certain fixed variable implicitly; option
  2914 show_structs controls printing of implicit structures.  Typical
  2915 applications of these concepts involve record types and locales.
  2916 
  2917 * New command 'no_syntax' removes grammar declarations (and
  2918 translations) resulting from the given syntax specification, which is
  2919 interpreted in the same manner as for the 'syntax' command.
  2920 
  2921 * 'Advanced' translation functions (parse_translation etc.) may depend
  2922 on the signature of the theory context being presently used for
  2923 parsing/printing, see also isar-ref manual.
  2924 
  2925 * Improved 'oracle' command provides a type-safe interface to turn an
  2926 ML expression of type theory -> T -> term into a primitive rule of
  2927 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2928 is already included here); see also FOL/ex/IffExample.thy;
  2929 INCOMPATIBILITY.
  2930 
  2931 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2932 before); "cI" is no longer bound, use "c.intro" instead.
  2933 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2934 axclasses vs. locales.
  2935 
  2936 * Improved internal renaming of symbolic identifiers -- attach primes
  2937 instead of base 26 numbers.
  2938 
  2939 * New flag show_question_marks controls printing of leading question
  2940 marks in schematic variable names.
  2941 
  2942 * In schematic variable names, *any* symbol following \<^isub> or
  2943 \<^isup> is now treated as part of the base name.  For example, the
  2944 following works without printing of awkward ".0" indexes:
  2945 
  2946   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2947     by simp
  2948 
  2949 * Inner syntax includes (*(*nested*) comments*).
  2950 
  2951 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2952 annotations as "(00...)".
  2953 
  2954 * Clear separation of logical types and nonterminals, where the latter
  2955 may only occur in 'syntax' specifications or type abbreviations.
  2956 Before that distinction was only partially implemented via type class
  2957 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2958 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2959 exotic syntax specifications may require further adaption
  2960 (e.g. Cube/Cube.thy).
  2961 
  2962 * Removed obsolete type class "logic", use the top sort {} instead.
  2963 Note that non-logical types should be declared as 'nonterminals'
  2964 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2965 specifications.
  2966 
  2967 * Attributes 'induct' and 'cases': type or set names may now be
  2968 locally fixed variables as well.
  2969 
  2970 * Simplifier: can now control the depth to which conditional rewriting
  2971 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2972 Limit.
  2973 
  2974 * Simplifier: simplification procedures may now take the current
  2975 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2976 interface), which is very useful for calling the Simplifier
  2977 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2978 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2979 low-level mk_simproc no longer applies Logic.varify internally, to
  2980 allow for use in a context of fixed variables.
  2981 
  2982 * thin_tac now works even if the assumption being deleted contains !!
  2983 or ==>.  More generally, erule now works even if the major premise of
  2984 the elimination rule contains !! or ==>.
  2985 
  2986 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2987 
  2988 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2989 from Pure, which contains all common declarations already.  Both
  2990 theories are defined via plain Isabelle/Isar .thy files.
  2991 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2992 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2993 use isatool fixcpure to adapt your theory and ML sources.
  2994 
  2995 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2996 selections of theorems in named facts via index ranges.
  2997 
  2998 * 'print_theorems': in theory mode, really print the difference
  2999 wrt. the last state (works for interactive theory development only),
  3000 in proof mode print all local facts (cf. 'print_facts');
  3001 
  3002 * 'hide': option '(open)' hides only base names.
  3003 
  3004 * More efficient treatment of intermediate checkpoints in interactive
  3005 theory development.
  3006 
  3007 * Code generator is now invoked via code_module (incremental code
  3008 generation) and code_library (modular code generation, ML structures
  3009 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  3010 must be quoted when used as identifiers.
  3011 
  3012 * New 'value' command for reading, evaluating and printing terms using
  3013 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  3014 quoted when used as identifier.
  3015 
  3016 
  3017 *** Locales ***
  3018 
  3019 * New commands for the interpretation of locale expressions in
  3020 theories (1), locales (2) and proof contexts (3).  These generate
  3021 proof obligations from the expression specification.  After the
  3022 obligations have been discharged, theorems of the expression are added
  3023 to the theory, target locale or proof context.  The synopsis of the
  3024 commands is a follows:
  3025 
  3026   (1) interpretation expr inst
  3027   (2) interpretation target < expr
  3028   (3) interpret expr inst
  3029 
  3030 Interpretation in theories and proof contexts require a parameter
  3031 instantiation of terms from the current context.  This is applied to
  3032 specifications and theorems of the interpreted expression.
  3033 Interpretation in locales only permits parameter renaming through the
  3034 locale expression.  Interpretation is smart in that interpretations
  3035 that are active already do not occur in proof obligations, neither are
  3036 instantiated theorems stored in duplicate.  Use 'print_interps' to
  3037 inspect active interpretations of a particular locale.  For details,
  3038 see the Isar Reference manual.  Examples can be found in
  3039 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  3040 
  3041 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  3042 'interpret' instead.
  3043 
  3044 * New context element 'constrains' for adding type constraints to
  3045 parameters.
  3046 
  3047 * Context expressions: renaming of parameters with syntax
  3048 redeclaration.
  3049 
  3050 * Locale declaration: 'includes' disallowed.
  3051 
  3052 * Proper static binding of attribute syntax -- i.e. types / terms /
  3053 facts mentioned as arguments are always those of the locale definition
  3054 context, independently of the context of later invocations.  Moreover,
  3055 locale operations (renaming and type / term instantiation) are applied
  3056 to attribute arguments as expected.
  3057 
  3058 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  3059 actual attributes; rare situations may require Attrib.attribute to
  3060 embed those attributes into Attrib.src that lack concrete syntax.
  3061 Attribute implementations need to cooperate properly with the static
  3062 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  3063 Attrib.XXX_thm etc. already do the right thing without further
  3064 intervention.  Only unusual applications -- such as "where" or "of"
  3065 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  3066 on the context and the facts involved -- may have to assign parsed
  3067 values to argument tokens explicitly.
  3068 
  3069 * Changed parameter management in theorem generation for long goal
  3070 statements with 'includes'.  INCOMPATIBILITY: produces a different
  3071 theorem statement in rare situations.
  3072 
  3073 * Locale inspection command 'print_locale' omits notes elements.  Use
  3074 'print_locale!' to have them included in the output.
  3075 
  3076 
  3077 *** Provers ***
  3078 
  3079 * Provers/hypsubst.ML: improved version of the subst method, for
  3080 single-step rewriting: it now works in bound variable contexts. New is
  3081 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  3082 rewrite a different subterm than the original subst method, which is
  3083 still available as 'simplesubst'.
  3084 
  3085 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  3086 and quasi orders.
  3087 
  3088 * Provers/trancl.ML: new transitivity reasoner for transitive and
  3089 reflexive-transitive closure of relations.
  3090 
  3091 * Provers/blast.ML: new reference depth_limit to make blast's depth
  3092 limit (previously hard-coded with a value of 20) user-definable.
  3093 
  3094 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  3095 is peformed already.  Object-logics merely need to finish their
  3096 initial simpset configuration as before.  INCOMPATIBILITY.
  3097 
  3098 
  3099 *** HOL ***
  3100 
  3101 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  3102 
  3103   syntax (epsilon)
  3104     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  3105 
  3106 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  3107 and x-symbol; use option '-m epsilon' to get it actually printed.
  3108 Moreover, the mathematically important symbolic identifier \<epsilon>
  3109 becomes available as variable, constant etc.  INCOMPATIBILITY,
  3110 
  3111 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  3112 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  3113 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  3114 support corresponding Isar calculations.
  3115 
  3116 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  3117 instead of ":".
  3118 
  3119 * theory SetInterval: changed the syntax for open intervals:
  3120 
  3121   Old       New
  3122   {..n(}    {..<n}
  3123   {)n..}    {n<..}
  3124   {m..n(}   {m..<n}
  3125   {)m..n}   {m<..n}
  3126   {)m..n(}  {m<..<n}
  3127 
  3128 The old syntax is still supported but will disappear in the next
  3129 release.  For conversion use the following Emacs search and replace
  3130 patterns (these are not perfect but work quite well):
  3131 
  3132   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  3133   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  3134 
  3135 * Theory Commutative_Ring (in Library): method comm_ring for proving
  3136 equalities in commutative rings; method 'algebra' provides a generic
  3137 interface.
  3138 
  3139 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  3140 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  3141 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  3142 be a tuple pattern.
  3143 
  3144 Some new syntax forms are available:
  3145 
  3146   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  3147   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  3148   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  3149   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  3150 
  3151 The latter form "\<Sum>x < k. e" used to be based on a separate
  3152 function "Summation", which has been discontinued.
  3153 
  3154 * theory Finite_Set: in structured induction proofs, the insert case
  3155 is now 'case (insert x F)' instead of the old counterintuitive 'case
  3156 (insert F x)'.
  3157 
  3158 * The 'refute' command has been extended to support a much larger
  3159 fragment of HOL, including axiomatic type classes, constdefs and
  3160 typedefs, inductive datatypes and recursion.
  3161 
  3162 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  3163 Requires zChaff with proof generation to be installed.  See
  3164 HOL/ex/SAT_Examples.thy for examples.
  3165 
  3166 * Datatype induction via method 'induct' now preserves the name of the
  3167 induction variable. For example, when proving P(xs::'a list) by
  3168 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  3169 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  3170 in unstructured proof scripts.
  3171 
  3172 * Reworked implementation of records.  Improved scalability for
  3173 records with many fields, avoiding performance problems for type
  3174 inference. Records are no longer composed of nested field types, but
  3175 of nested extension types. Therefore the record type only grows linear
  3176 in the number of extensions and not in the number of fields.  The
  3177 top-level (users) view on records is preserved.  Potential
  3178 INCOMPATIBILITY only in strange cases, where the theory depends on the
  3179 old record representation. The type generated for a record is called
  3180 <record_name>_ext_type.
  3181 
  3182 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  3183 proofs triggered by a record definition or a simproc (if
  3184 quick_and_dirty is enabled).  Definitions of large records can take
  3185 quite long.
  3186 
  3187 New simproc record_upd_simproc for simplification of multiple record
  3188 updates enabled by default.  Moreover, trivial updates are also
  3189 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  3190 occasionally, since simplification is more powerful by default.
  3191 
  3192 * typedef: proper support for polymorphic sets, which contain extra
  3193 type-variables in the term.
  3194 
  3195 * Simplifier: automatically reasons about transitivity chains
  3196 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  3197 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  3198 old proofs break occasionally as simplification may now solve more
  3199 goals than previously.
  3200 
  3201 * Simplifier: converts x <= y into x = y if assumption y <= x is
  3202 present.  Works for all partial orders (class "order"), in particular
  3203 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  3204 just like y <= x.
  3205 
  3206 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  3207 bound variable or a constant then the let is unfolded.  Otherwise
  3208 first a is simplified to b, and then f b is simplified to g. If
  3209 possible we abstract b from g arriving at "let x = b in h x",
  3210 otherwise we unfold the let and arrive at g.  The simproc can be
  3211 enabled/disabled by the reference use_let_simproc.  Potential
  3212 INCOMPATIBILITY since simplification is more powerful by default.
  3213 
  3214 * Classical reasoning: the meson method now accepts theorems as arguments.
  3215 
  3216 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  3217 jobs to provide advice on the provability of subgoals.
  3218 
  3219 * Theory OrderedGroup and Ring_and_Field: various additions and
  3220 improvements to faciliate calculations involving equalities and
  3221 inequalities.
  3222 
  3223 The following theorems have been eliminated or modified
  3224 (INCOMPATIBILITY):
  3225 
  3226   abs_eq             now named abs_of_nonneg
  3227   abs_of_ge_0        now named abs_of_nonneg
  3228   abs_minus_eq       now named abs_of_nonpos
  3229   imp_abs_id         now named abs_of_nonneg
  3230   imp_abs_neg_id     now named abs_of_nonpos
  3231   mult_pos           now named mult_pos_pos
  3232   mult_pos_le        now named mult_nonneg_nonneg
  3233   mult_pos_neg_le    now named mult_nonneg_nonpos
  3234   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  3235   mult_neg           now named mult_neg_neg
  3236   mult_neg_le        now named mult_nonpos_nonpos
  3237 
  3238 * The following lemmas in Ring_and_Field have been added to the simplifier:
  3239      
  3240      zero_le_square
  3241      not_square_less_zero 
  3242 
  3243   The following lemmas have been deleted from Real/RealPow:
  3244   
  3245      realpow_zero_zero
  3246      realpow_two
  3247      realpow_less
  3248      zero_le_power
  3249      realpow_two_le
  3250      abs_realpow_two
  3251      realpow_two_abs     
  3252 
  3253 * Theory Parity: added rules for simplifying exponents.
  3254 
  3255 * Theory List:
  3256 
  3257 The following theorems have been eliminated or modified
  3258 (INCOMPATIBILITY):
  3259 
  3260   list_all_Nil       now named list_all.simps(1)
  3261   list_all_Cons      now named list_all.simps(2)
  3262   list_all_conv      now named list_all_iff
  3263   set_mem_eq         now named mem_iff
  3264 
  3265 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  3266 asymptotic "big O" calculations.  See the notes in BigO.thy.
  3267 
  3268 
  3269 *** HOL-Complex ***
  3270 
  3271 * Theory RealDef: better support for embedding natural numbers and
  3272 integers in the reals.
  3273 
  3274 The following theorems have been eliminated or modified
  3275 (INCOMPATIBILITY):
  3276 
  3277   exp_ge_add_one_self  now requires no hypotheses
  3278   real_of_int_add      reversed direction of equality (use [symmetric])
  3279   real_of_int_minus    reversed direction of equality (use [symmetric])
  3280   real_of_int_diff     reversed direction of equality (use [symmetric])
  3281   real_of_int_mult     reversed direction of equality (use [symmetric])
  3282 
  3283 * Theory RComplete: expanded support for floor and ceiling functions.
  3284 
  3285 * Theory Ln is new, with properties of the natural logarithm
  3286 
  3287 * Hyperreal: There is a new type constructor "star" for making
  3288 nonstandard types.  The old type names are now type synonyms:
  3289 
  3290   hypreal = real star
  3291   hypnat = nat star
  3292   hcomplex = complex star
  3293 
  3294 * Hyperreal: Many groups of similarly-defined constants have been
  3295 replaced by polymorphic versions (INCOMPATIBILITY):
  3296 
  3297   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  3298 
  3299   starset      <-- starsetNat, starsetC
  3300   *s*          <-- *sNat*, *sc*
  3301   starset_n    <-- starsetNat_n, starsetC_n
  3302   *sn*         <-- *sNatn*, *scn*
  3303   InternalSets <-- InternalNatSets, InternalCSets
  3304 
  3305   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  3306   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  3307   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  3308   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  3309   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  3310 
  3311 * Hyperreal: Many type-specific theorems have been removed in favor of
  3312 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  3313 
  3314   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  3315   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  3316   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  3317   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  3318   right_minus <-- hypreal_add_minus
  3319   left_minus <-- {hypreal,hcomplex}_add_minus_left
  3320   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  3321   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  3322   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  3323   mult_1_right <-- hcomplex_mult_one_right
  3324   mult_zero_left <-- hcomplex_mult_zero_left
  3325   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  3326   right_distrib <-- hypnat_add_mult_distrib2
  3327   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  3328   right_inverse <-- hypreal_mult_inverse
  3329   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  3330   order_refl <-- {hypreal,hypnat}_le_refl
  3331   order_trans <-- {hypreal,hypnat}_le_trans
  3332   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  3333   order_less_le <-- {hypreal,hypnat}_less_le
  3334   linorder_linear <-- {hypreal,hypnat}_le_linear
  3335   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  3336   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  3337   add_nonneg_nonneg <-- hypreal_le_add_order
  3338 
  3339 * Hyperreal: Separate theorems having to do with type-specific
  3340 versions of constants have been merged into theorems that apply to the
  3341 new polymorphic constants (INCOMPATIBILITY):
  3342 
  3343   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  3344   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  3345   STAR_Un <-- {STAR,NatStar,STARC}_Un
  3346   STAR_Int <-- {STAR,NatStar,STARC}_Int
  3347   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  3348   STAR_subset <-- {STAR,NatStar,STARC}_subset
  3349   STAR_mem <-- {STAR,NatStar,STARC}_mem
  3350   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  3351   STAR_diff <-- {STAR,STARC}_diff
  3352   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  3353     STARC_hcomplex_of_complex}_image_subset
  3354   starset_n_Un <-- starset{Nat,C}_n_Un
  3355   starset_n_Int <-- starset{Nat,C}_n_Int
  3356   starset_n_Compl <-- starset{Nat,C}_n_Compl
  3357   starset_n_diff <-- starset{Nat,C}_n_diff
  3358   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  3359   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  3360   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  3361   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  3362   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  3363   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  3364   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  3365   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  3366   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  3367   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  3368   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  3369   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  3370   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  3371   starfun_diff <-- starfun{C,RC,CR}_diff
  3372   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  3373   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  3374   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  3375   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  3376   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  3377   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  3378   starfun_Id <-- starfunC_Id
  3379   starfun_approx <-- starfun{Nat,CR}_approx
  3380   starfun_capprox <-- starfun{C,RC}_capprox
  3381   starfun_abs <-- starfunNat_rabs
  3382   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  3383   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  3384   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  3385   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  3386   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  3387   starfun_add_approx <-- starfunCR_add_approx
  3388   starfun_inverse_inverse <-- starfunC_inverse_inverse
  3389   starfun_divide <-- starfun{C,CR,RC}_divide
  3390   starfun_n <-- starfun{Nat,C}_n
  3391   starfun_n_mult <-- starfun{Nat,C}_n_mult
  3392   starfun_n_add <-- starfun{Nat,C}_n_add
  3393   starfun_n_add_minus <-- starfunNat_n_add_minus
  3394   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  3395   starfun_n_minus <-- starfun{Nat,C}_n_minus
  3396   starfun_n_eq <-- starfun{Nat,C}_n_eq
  3397 
  3398   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  3399   star_n_minus <-- {hypreal,hcomplex}_minus
  3400   star_n_diff <-- {hypreal,hcomplex}_diff
  3401   star_n_mult <-- {hypreal,hcomplex}_mult
  3402   star_n_inverse <-- {hypreal,hcomplex}_inverse
  3403   star_n_le <-- {hypreal,hypnat}_le
  3404   star_n_less <-- {hypreal,hypnat}_less
  3405   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  3406   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  3407   star_n_abs <-- hypreal_hrabs
  3408   star_n_divide <-- hcomplex_divide
  3409 
  3410   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  3411   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  3412   star_of_diff <-- hypreal_of_real_diff
  3413   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  3414   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  3415   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  3416   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  3417   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  3418   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  3419   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  3420   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  3421   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  3422   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  3423   star_of_number_of <-- {hypreal,hcomplex}_number_of
  3424   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  3425   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  3426   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  3427   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  3428   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  3429   star_of_power <-- hypreal_of_real_power
  3430   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  3431 
  3432 * Hyperreal: new method "transfer" that implements the transfer
  3433 principle of nonstandard analysis. With a subgoal that mentions
  3434 nonstandard types like "'a star", the command "apply transfer"
  3435 replaces it with an equivalent one that mentions only standard types.
  3436 To be successful, all free variables must have standard types; non-
  3437 standard variables must have explicit universal quantifiers.
  3438 
  3439 * Hyperreal: A theory of Taylor series.
  3440 
  3441 
  3442 *** HOLCF ***
  3443 
  3444 * Discontinued special version of 'constdefs' (which used to support
  3445 continuous functions) in favor of the general Pure one with full
  3446 type-inference.
  3447 
  3448 * New simplification procedure for solving continuity conditions; it
  3449 is much faster on terms with many nested lambda abstractions (cubic
  3450 instead of exponential time).
  3451 
  3452 * New syntax for domain package: selector names are now optional.
  3453 Parentheses should be omitted unless argument is lazy, for example:
  3454 
  3455   domain 'a stream = cons "'a" (lazy "'a stream")
  3456 
  3457 * New command 'fixrec' for defining recursive functions with pattern
  3458 matching; defining multiple functions with mutual recursion is also
  3459 supported.  Patterns may include the constants cpair, spair, up, sinl,
  3460 sinr, or any data constructor defined by the domain package. The given
  3461 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  3462 syntax and examples.
  3463 
  3464 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  3465 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  3466 but the proof obligation additionally includes an admissibility
  3467 requirement. The packages generate instances of class cpo or pcpo,
  3468 with continuity and strictness theorems for Rep and Abs.
  3469 
  3470 * HOLCF: Many theorems have been renamed according to a more standard naming
  3471 scheme (INCOMPATIBILITY):
  3472 
  3473   foo_inject:  "foo$x = foo$y ==> x = y"
  3474   foo_eq:      "(foo$x = foo$y) = (x = y)"
  3475   foo_less:    "(foo$x << foo$y) = (x << y)"
  3476   foo_strict:  "foo$UU = UU"
  3477   foo_defined: "... ==> foo$x ~= UU"
  3478   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  3479 
  3480 
  3481 *** ZF ***
  3482 
  3483 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  3484 including the First Isomorphism Theorem (on quotienting by the kernel
  3485 of a homomorphism).
  3486 
  3487 * ZF/Simplifier: install second copy of type solver that actually
  3488 makes use of TC rules declared to Isar proof contexts (or locales);
  3489 the old version is still required for ML proof scripts.
  3490 
  3491 
  3492 *** Cube ***
  3493 
  3494 * Converted to Isar theory format; use locales instead of axiomatic
  3495 theories.
  3496 
  3497 
  3498 *** ML ***
  3499 
  3500 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  3501 for ||>, ||>>, |>>,
  3502 
  3503 * Pure/library.ML no longer defines its own option datatype, but uses
  3504 that of the SML basis, which has constructors NONE and SOME instead of
  3505 None and Some, as well as exception Option.Option instead of OPTION.
  3506 The functions the, if_none, is_some, is_none have been adapted
  3507 accordingly, while Option.map replaces apsome.
  3508 
  3509 * Pure/library.ML: the exception LIST has been given up in favour of
  3510 the standard exceptions Empty and Subscript, as well as
  3511 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  3512 superceded by the standard hd and tl functions etc.
  3513 
  3514 A number of basic list functions are no longer exported to the ML
  3515 toplevel, as they are variants of predefined functions.  The following
  3516 suggests how one can translate existing code:
  3517 
  3518     rev_append xs ys = List.revAppend (xs, ys)
  3519     nth_elem (i, xs) = List.nth (xs, i)
  3520     last_elem xs = List.last xs
  3521     flat xss = List.concat xss
  3522     seq fs = List.app fs
  3523     partition P xs = List.partition P xs
  3524     mapfilter f xs = List.mapPartial f xs
  3525 
  3526 * Pure/library.ML: several combinators for linear functional
  3527 transformations, notably reverse application and composition:
  3528 
  3529   x |> f                f #> g
  3530   (x, y) |-> f          f #-> g
  3531 
  3532 * Pure/library.ML: introduced/changed precedence of infix operators:
  3533 
  3534   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  3535   infix 2 ?;
  3536   infix 3 o oo ooo oooo;
  3537   infix 4 ~~ upto downto;
  3538 
  3539 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  3540 infix operators.
  3541 
  3542 * Pure/library.ML: natural list combinators fold, fold_rev, and
  3543 fold_map support linear functional transformations and nesting.  For
  3544 example:
  3545 
  3546   fold f [x1, ..., xN] y =
  3547     y |> f x1 |> ... |> f xN
  3548 
  3549   (fold o fold) f [xs1, ..., xsN] y =
  3550     y |> fold f xs1 |> ... |> fold f xsN
  3551 
  3552   fold f [x1, ..., xN] =
  3553     f x1 #> ... #> f xN
  3554 
  3555   (fold o fold) f [xs1, ..., xsN] =
  3556     fold f xs1 #> ... #> fold f xsN
  3557 
  3558 * Pure/library.ML: the following selectors on type 'a option are
  3559 available:
  3560 
  3561   the:               'a option -> 'a  (*partial*)
  3562   these:             'a option -> 'a  where 'a = 'b list
  3563   the_default: 'a -> 'a option -> 'a
  3564   the_list:          'a option -> 'a list
  3565 
  3566 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3567 basic operations for association lists, following natural argument
  3568 order; moreover the explicit equality predicate passed here avoids
  3569 potentially expensive polymorphic runtime equality checks.
  3570 The old functions may be expressed as follows:
  3571 
  3572   assoc = uncurry (AList.lookup (op =))
  3573   assocs = these oo AList.lookup (op =)
  3574   overwrite = uncurry (AList.update (op =)) o swap
  3575 
  3576 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  3577 
  3578   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  3579   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  3580 
  3581 replacing make_keylist and keyfilter (occassionally used)
  3582 Naive rewrites:
  3583 
  3584   make_keylist = AList.make
  3585   keyfilter = AList.find (op =)
  3586 
  3587 * eq_fst and eq_snd now take explicit equality parameter, thus
  3588   avoiding eqtypes. Naive rewrites:
  3589 
  3590     eq_fst = eq_fst (op =)
  3591     eq_snd = eq_snd (op =)
  3592 
  3593 * Removed deprecated apl and apr (rarely used).
  3594   Naive rewrites:
  3595 
  3596     apl (n, op) =>>= curry op n
  3597     apr (op, m) =>>= fn n => op (n, m)
  3598 
  3599 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  3600 provides a reasonably efficient light-weight implementation of sets as
  3601 lists.
  3602 
  3603 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  3604 few new operations; existing lookup and update are now curried to
  3605 follow natural argument order (for use with fold etc.);
  3606 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  3607 
  3608 * Pure/General: output via the Isabelle channels of
  3609 writeln/warning/error etc. is now passed through Output.output, with a
  3610 hook for arbitrary transformations depending on the print_mode
  3611 (cf. Output.add_mode -- the first active mode that provides a output
  3612 function wins).  Already formatted output may be embedded into further
  3613 text via Output.raw; the result of Pretty.string_of/str_of and derived
  3614 functions (string_of_term/cterm/thm etc.) is already marked raw to
  3615 accommodate easy composition of diagnostic messages etc.  Programmers
  3616 rarely need to care about Output.output or Output.raw at all, with
  3617 some notable exceptions: Output.output is required when bypassing the
  3618 standard channels (writeln etc.), or in token translations to produce
  3619 properly formatted results; Output.raw is required when capturing
  3620 already output material that will eventually be presented to the user
  3621 a second time.  For the default print mode, both Output.output and
  3622 Output.raw have no effect.
  3623 
  3624 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  3625 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  3626 cumulative results are displayed at the end of a batch session.
  3627 
  3628 * Pure/General: File.sysify_path and File.quote_sysify path have been
  3629 replaced by File.platform_path and File.shell_path (with appropriate
  3630 hooks).  This provides a clean interface for unusual systems where the
  3631 internal and external process view of file names are different.
  3632 
  3633 * Pure: more efficient orders for basic syntactic entities: added
  3634 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  3635 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  3636 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  3637 orders now -- potential INCOMPATIBILITY for code that depends on a
  3638 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  3639 Library.sort_strings on result).
  3640 
  3641 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  3642 fold_types traverse types/terms from left to right, observing natural
  3643 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  3644 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  3645 
  3646 * Pure: name spaces have been refined, with significant changes of the
  3647 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  3648 to extern(_table).  The plain name entry path is superceded by a
  3649 general 'naming' context, which also includes the 'policy' to produce
  3650 a fully qualified name and external accesses of a fully qualified
  3651 name; NameSpace.extend is superceded by context dependent
  3652 Sign.declare_name.  Several theory and proof context operations modify
  3653 the naming context.  Especially note Theory.restore_naming and
  3654 ProofContext.restore_naming to get back to a sane state; note that
  3655 Theory.add_path is no longer sufficient to recover from
  3656 Theory.absolute_path in particular.
  3657 
  3658 * Pure: new flags short_names (default false) and unique_names
  3659 (default true) for controlling output of qualified names.  If
  3660 short_names is set, names are printed unqualified.  If unique_names is
  3661 reset, the name prefix is reduced to the minimum required to achieve
  3662 the original result when interning again, even if there is an overlap
  3663 with earlier declarations.
  3664 
  3665 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  3666 now 'extend', and 'merge' gets an additional Pretty.pp argument
  3667 (useful for printing error messages).  INCOMPATIBILITY.
  3668 
  3669 * Pure: major reorganization of the theory context.  Type Sign.sg and
  3670 Theory.theory are now identified, referring to the universal
  3671 Context.theory (see Pure/context.ML).  Actual signature and theory
  3672 content is managed as theory data.  The old code and interfaces were
  3673 spread over many files and structures; the new arrangement introduces
  3674 considerable INCOMPATIBILITY to gain more clarity:
  3675 
  3676   Context -- theory management operations (name, identity, inclusion,
  3677     parents, ancestors, merge, etc.), plus generic theory data;
  3678 
  3679   Sign -- logical signature and syntax operations (declaring consts,
  3680     types, etc.), plus certify/read for common entities;
  3681 
  3682   Theory -- logical theory operations (stating axioms, definitions,
  3683     oracles), plus a copy of logical signature operations (consts,
  3684     types, etc.); also a few basic management operations (Theory.copy,
  3685     Theory.merge, etc.)
  3686 
  3687 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3688 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3689 for convenience -- they merely return the theory.
  3690 
  3691 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3692 
  3693 * Pure: the Isar proof context type is already defined early in Pure
  3694 as Context.proof (note that ProofContext.context and Proof.context are
  3695 aliases, where the latter is the preferred name).  This enables other
  3696 Isabelle components to refer to that type even before Isar is present.
  3697 
  3698 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3699 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3700 any of these kinds.  For example, Sign.intern typeK is now
  3701 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3702 Theory.hide_types.  Also note that former
  3703 Theory.hide_classes/types/consts are now
  3704 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3705 internalize their arguments!  INCOMPATIBILITY.
  3706 
  3707 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3708 datatype thmref (with constructors Name and NameSelection) instead of
  3709 plain string -- INCOMPATIBILITY;
  3710 
  3711 * Pure: cases produced by proof methods specify options, where NONE
  3712 means to remove case bindings -- INCOMPATIBILITY in
  3713 (RAW_)METHOD_CASES.
  3714 
  3715 * Pure: the following operations retrieve axioms or theorems from a
  3716 theory node or theory hierarchy, respectively:
  3717 
  3718   Theory.axioms_of: theory -> (string * term) list
  3719   Theory.all_axioms_of: theory -> (string * term) list
  3720   PureThy.thms_of: theory -> (string * thm) list
  3721   PureThy.all_thms_of: theory -> (string * thm) list
  3722 
  3723 * Pure: print_tac now outputs the goal through the trace channel.
  3724 
  3725 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3726 Reference Toplevel.debug (default false) controls detailed printing
  3727 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3728 controls execution profiling -- set to 1 for time and 2 for space
  3729 (both increase the runtime).
  3730 
  3731 * Isar session: The initial use of ROOT.ML is now always timed,
  3732 i.e. the log will show the actual process times, in contrast to the
  3733 elapsed wall-clock time that the outer shell wrapper produces.
  3734 
  3735 * Simplifier: improved handling of bound variables (nameless
  3736 representation, avoid allocating new strings).  Simprocs that invoke
  3737 the Simplifier recursively should use Simplifier.inherit_bounds to
  3738 avoid local name clashes.  Failure to do so produces warnings
  3739 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3740 for further details.
  3741 
  3742 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3743 bindings for all theorems stored within a given theory; this may help
  3744 in porting non-Isar theories to Isar ones, while keeping ML proof
  3745 scripts for the time being.
  3746 
  3747 * ML operator HTML.with_charset specifies the charset begin used for
  3748 generated HTML files.  For example:
  3749 
  3750   HTML.with_charset "utf-8" use_thy "Hebrew";
  3751   HTML.with_charset "utf-8" use_thy "Chinese";
  3752 
  3753 
  3754 *** System ***
  3755 
  3756 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3757 isabelle, isatool etc.).
  3758 
  3759 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3760 isatool doc, isatool mkdir, display_drafts etc.).
  3761 
  3762 * isatool usedir: option -f allows specification of the ML file to be
  3763 used by Isabelle; default is ROOT.ML.
  3764 
  3765 * New isatool version outputs the version identifier of the Isabelle
  3766 distribution being used.
  3767 
  3768 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3769 (containing Boolean satisfiability problems) into Isabelle/HOL
  3770 theories.
  3771 
  3772 
  3773 
  3774 New in Isabelle2004 (April 2004)
  3775 --------------------------------
  3776 
  3777 *** General ***
  3778 
  3779 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3780   Replaces linorder.ML.
  3781 
  3782 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3783   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3784   (\<a>...\<z>), are now considered normal letters, and can therefore
  3785   be used anywhere where an ASCII letter (a...zA...Z) has until
  3786   now. COMPATIBILITY: This obviously changes the parsing of some
  3787   terms, especially where a symbol has been used as a binder, say
  3788   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3789   as an identifier.  Fix it by inserting a space around former
  3790   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3791   existing theory and ML files.
  3792 
  3793 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3794 
  3795 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3796   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3797   a normal (but invisible) letter. For multiple letter subscripts repeat
  3798   \<^isub> like this: x\<^isub>1\<^isub>2.
  3799 
  3800 * Pure: There are now sub-/superscripts that can span more than one
  3801   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3802   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3803   superscript. The new control characters are not identifier parts.
  3804 
  3805 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3806   content of "..." to the latex file instead of \isacntrl... . The "..."
  3807   may consist of any printable characters excluding the end bracket >.
  3808 
  3809 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3810   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3811   declare constants "final", which prevents their being given a definition
  3812   later.  It is useful for constants whose behaviour is fixed axiomatically
  3813   rather than definitionally, such as the meta-logic connectives.
  3814 
  3815 * Pure: 'instance' now handles general arities with general sorts
  3816   (i.e. intersections of classes),
  3817 
  3818 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3819   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3820   It can be changed to alter the colors/layout of generated pages.
  3821 
  3822 
  3823 *** Isar ***
  3824 
  3825 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3826   cut_tac, subgoal_tac and thin_tac:
  3827   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3828     locales are no longer forced to write Isar proof scripts.
  3829     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3830     emulations.
  3831   - INCOMPATIBILITY: names of variables to be instantiated may no
  3832     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3833     This is consistent with the instantiation attribute "where".
  3834 
  3835 * Attributes "where" and "of":
  3836   - Now take type variables of instantiated theorem into account when reading
  3837     the instantiation string.  This fixes a bug that caused instantiated
  3838     theorems to have too special types in some circumstances.
  3839   - "where" permits explicit instantiations of type variables.
  3840 
  3841 * Calculation commands "moreover" and "also" no longer interfere with
  3842   current facts ("this"), admitting arbitrary combinations with "then"
  3843   and derived forms.
  3844 
  3845 * Locales:
  3846   - Goal statements involving the context element "includes" no longer
  3847     generate theorems with internal delta predicates (those ending on
  3848     "_axioms") in the premise.
  3849     Resolve particular premise with <locale>.intro to obtain old form.
  3850   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3851     specification and "includes" elements in goal statement.
  3852   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3853     [intro?] and [elim?] (respectively) by default.
  3854   - Experimental command for instantiation of locales in proof contexts:
  3855         instantiate <label>[<attrs>]: <loc>
  3856     Instantiates locale <loc> and adds all its theorems to the current context
  3857     taking into account their attributes.  Label and attrs are optional
  3858     modifiers, like in theorem declarations.  If present, names of
  3859     instantiated theorems are qualified with <label>, and the attributes
  3860     <attrs> are applied after any attributes these theorems might have already.
  3861       If the locale has assumptions, a chained fact of the form
  3862     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3863     are derived.  The command does not support old-style locales declared
  3864     with "locale (open)".
  3865       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3866 
  3867 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3868   (Isar) contexts.
  3869 
  3870 
  3871 *** HOL ***
  3872 
  3873 * Proof import: new image HOL4 contains the imported library from
  3874   the HOL4 system with about 2500 theorems. It is imported by
  3875   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3876   can be used like any other Isabelle image.  See
  3877   HOL/Import/HOL/README for more information.
  3878 
  3879 * Simplifier:
  3880   - Much improved handling of linear and partial orders.
  3881     Reasoners for linear and partial orders are set up for type classes
  3882     "linorder" and "order" respectively, and are added to the default simpset
  3883     as solvers.  This means that the simplifier can build transitivity chains
  3884     to solve goals from the assumptions.
  3885   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3886     of blast or auto after simplification become unnecessary because the goal
  3887     is solved by simplification already.
  3888 
  3889 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3890     all proved in axiomatic type classes for semirings, rings and fields.
  3891 
  3892 * Numerics:
  3893   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3894     now formalized using the Ring_and_Field theory mentioned above.
  3895   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3896     than before, because now they are set up once in a generic manner.
  3897   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3898     Look for the general versions in Ring_and_Field (and Power if they concern
  3899     exponentiation).
  3900 
  3901 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3902 
  3903 * Records:
  3904   - Record types are now by default printed with their type abbreviation
  3905     instead of the list of all field types. This can be configured via
  3906     the reference "print_record_type_abbr".
  3907   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3908     (not enabled by default).
  3909   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3910     EX x. x = sel r to True (not enabled by default).
  3911   - Tactic "record_split_simp_tac" to split and simplify records added.
  3912 
  3913 * 'specification' command added, allowing for definition by
  3914   specification.  There is also an 'ax_specification' command that
  3915   introduces the new constants axiomatically.
  3916 
  3917 * arith(_tac) is now able to generate counterexamples for reals as well.
  3918 
  3919 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3920 
  3921 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3922   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3923 
  3924 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3925   matrix theory to linear programming.
  3926 
  3927 * Unions and Intersections:
  3928   The latex output syntax of UN and INT has been changed
  3929   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3930   i.e. the index formulae has become a subscript.
  3931   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3932 
  3933 * Unions and Intersections over Intervals:
  3934   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3935   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3936   like in normal math, and corresponding versions for < and for intersection.
  3937 
  3938 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3939   lexicographic dictonary ordering has been added as "lexord".
  3940 
  3941 * ML: the legacy theory structures Int and List have been removed. They had
  3942   conflicted with ML Basis Library structures having the same names.
  3943 
  3944 * 'refute' command added to search for (finite) countermodels.  Only works
  3945   for a fragment of HOL.  The installation of an external SAT solver is
  3946   highly recommended.  See "HOL/Refute.thy" for details.
  3947 
  3948 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3949   formulae under an assignment of free variables to random values.
  3950   In contrast to 'refute', it can deal with inductive datatypes,
  3951   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3952   for examples.
  3953 
  3954 
  3955 *** HOLCF ***
  3956 
  3957 * Streams now come with concatenation and are part of the HOLCF image
  3958 
  3959 
  3960 
  3961 New in Isabelle2003 (May 2003)
  3962 ------------------------------
  3963 
  3964 *** General ***
  3965 
  3966 * Provers/simplifier:
  3967 
  3968   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3969     Assumptions are now subject to complete mutual simplification,
  3970     not just from left to right. The simplifier now preserves
  3971     the order of assumptions.
  3972 
  3973     Potential INCOMPATIBILITY:
  3974 
  3975     -- simp sometimes diverges where the old version did
  3976        not, e.g. invoking simp on the goal
  3977 
  3978         [| P (f x); y = x; f x = f y |] ==> Q
  3979 
  3980        now gives rise to the infinite reduction sequence
  3981 
  3982         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3983 
  3984        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3985        kind of problem.
  3986 
  3987     -- Tactics combining classical reasoner and simplification (such as auto)
  3988        are also affected by this change, because many of them rely on
  3989        simp. They may sometimes diverge as well or yield a different numbers
  3990        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3991        in case of problems. Sometimes subsequent calls to the classical
  3992        reasoner will fail because a preceeding call to the simplifier too
  3993        eagerly simplified the goal, e.g. deleted redundant premises.
  3994 
  3995   - The simplifier trace now shows the names of the applied rewrite rules
  3996 
  3997   - You can limit the number of recursive invocations of the simplifier
  3998     during conditional rewriting (where the simplifie tries to solve the
  3999     conditions before applying the rewrite rule):
  4000     ML "simp_depth_limit := n"
  4001     where n is an integer. Thus you can force termination where previously
  4002     the simplifier would diverge.
  4003 
  4004   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  4005 
  4006   - No longer aborts on failed congruence proof.  Instead, the
  4007     congruence is ignored.
  4008 
  4009 * Pure: New generic framework for extracting programs from constructive
  4010   proofs. See HOL/Extraction.thy for an example instantiation, as well
  4011   as HOL/Extraction for some case studies.
  4012 
  4013 * Pure: The main goal of the proof state is no longer shown by default, only
  4014 the subgoals. This behaviour is controlled by a new flag.
  4015    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  4016 (ML: Proof.show_main_goal).
  4017 
  4018 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  4019 rules whose conclusion matches subgoal 1:
  4020       PG menu: Isabelle/Isar -> Show me -> matching rules
  4021 The rules are ordered by how closely they match the subgoal.
  4022 In particular, rules that solve a subgoal outright are displayed first
  4023 (or rather last, the way they are printed).
  4024 (ML: ProofGeneral.print_intros())
  4025 
  4026 * Pure: New flag trace_unify_fail causes unification to print
  4027 diagnostic information (PG: in trace buffer) when it fails. This is
  4028 useful for figuring out why single step proofs like rule, erule or
  4029 assumption failed.
  4030 
  4031 * Pure: Locale specifications now produce predicate definitions
  4032 according to the body of text (covering assumptions modulo local
  4033 definitions); predicate "loc_axioms" covers newly introduced text,
  4034 while "loc" is cumulative wrt. all included locale expressions; the
  4035 latter view is presented only on export into the global theory
  4036 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  4037 on the old view without predicates;
  4038 
  4039 * Pure: predefined locales "var" and "struct" are useful for sharing
  4040 parameters (as in CASL, for example); just specify something like
  4041 ``var x + var y + struct M'' as import;
  4042 
  4043 * Pure: improved thms_containing: proper indexing of facts instead of
  4044 raw theorems; check validity of results wrt. current name space;
  4045 include local facts of proof configuration (also covers active
  4046 locales), cover fixed variables in index; may use "_" in term
  4047 specification; an optional limit for the number of printed facts may
  4048 be given (the default is 40);
  4049 
  4050 * Pure: disallow duplicate fact bindings within new-style theory files
  4051 (batch-mode only);
  4052 
  4053 * Provers: improved induct method: assumptions introduced by case
  4054 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  4055 the goal statement); "foo" still refers to all facts collectively;
  4056 
  4057 * Provers: the function blast.overloaded has been removed: all constants
  4058 are regarded as potentially overloaded, which improves robustness in exchange
  4059 for slight decrease in efficiency;
  4060 
  4061 * Provers/linorder: New generic prover for transitivity reasoning over
  4062 linear orders.  Note: this prover is not efficient!
  4063 
  4064 * Isar: preview of problems to finish 'show' now produce an error
  4065 rather than just a warning (in interactive mode);
  4066 
  4067 
  4068 *** HOL ***
  4069 
  4070 * arith(_tac)
  4071 
  4072  - Produces a counter example if it cannot prove a goal.
  4073    Note that the counter example may be spurious if the goal is not a formula
  4074    of quantifier-free linear arithmetic.
  4075    In ProofGeneral the counter example appears in the trace buffer.
  4076 
  4077  - Knows about div k and mod k where k is a numeral of type nat or int.
  4078 
  4079  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  4080    linear arithmetic fails. This takes account of quantifiers and divisibility.
  4081    Presburger arithmetic can also be called explicitly via presburger(_tac).
  4082 
  4083 * simp's arithmetic capabilities have been enhanced a bit: it now
  4084 takes ~= in premises into account (by performing a case split);
  4085 
  4086 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  4087 are distributed over a sum of terms;
  4088 
  4089 * New tactic "trans_tac" and method "trans" instantiate
  4090 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  4091 "<=", "<" and "=").
  4092 
  4093 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  4094 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  4095 
  4096 * 'typedef' command has new option "open" to suppress the set
  4097 definition;
  4098 
  4099 * functions Min and Max on finite sets have been introduced (theory
  4100 Finite_Set);
  4101 
  4102 * attribute [symmetric] now works for relations as well; it turns
  4103 (x,y) : R^-1 into (y,x) : R, and vice versa;
  4104 
  4105 * induct over a !!-quantified statement (say !!x1..xn):
  4106   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  4107 
  4108 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  4109 %x. None. Warning: empty_def now refers to the previously hidden definition
  4110 of the empty set.
  4111 
  4112 * Algebra: formalization of classical algebra.  Intended as base for
  4113 any algebraic development in Isabelle.  Currently covers group theory
  4114 (up to Sylow's theorem) and ring theory (Universal Property of
  4115 Univariate Polynomials).  Contributions welcome;
  4116 
  4117 * GroupTheory: deleted, since its material has been moved to Algebra;
  4118 
  4119 * Complex: new directory of the complex numbers with numeric constants,
  4120 nonstandard complex numbers, and some complex analysis, standard and
  4121 nonstandard (Jacques Fleuriot);
  4122 
  4123 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  4124 
  4125 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  4126 Fleuriot);
  4127 
  4128 * Real/HahnBanach: updated and adapted to locales;
  4129 
  4130 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  4131 Gray and Kramer);
  4132 
  4133 * UNITY: added the Meier-Sanders theory of progress sets;
  4134 
  4135 * MicroJava: bytecode verifier and lightweight bytecode verifier
  4136 as abstract algorithms, instantiated to the JVM;
  4137 
  4138 * Bali: Java source language formalization. Type system, operational
  4139 semantics, axiomatic semantics. Supported language features:
  4140 classes, interfaces, objects,virtual methods, static methods,
  4141 static/instance fields, arrays, access modifiers, definite
  4142 assignment, exceptions.
  4143 
  4144 
  4145 *** ZF ***
  4146 
  4147 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  4148 universe, etc.);
  4149 
  4150 * Main ZF: virtually all theories converted to new-style format;
  4151 
  4152 
  4153 *** ML ***
  4154 
  4155 * Pure: Tactic.prove provides sane interface for internal proofs;
  4156 omits the infamous "standard" operation, so this is more appropriate
  4157 than prove_goalw_cterm in many situations (e.g. in simprocs);
  4158 
  4159 * Pure: improved error reporting of simprocs;
  4160 
  4161 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  4162 up simprocs;
  4163 
  4164 
  4165 *** Document preparation ***
  4166 
  4167 * uses \par instead of \\ for line breaks in theory text. This may
  4168 shift some page breaks in large documents. To get the old behaviour
  4169 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  4170 
  4171 * minimized dependencies of isabelle.sty and isabellesym.sty on
  4172 other packages
  4173 
  4174 * \<euro> now needs package babel/greek instead of marvosym (which
  4175 broke \Rightarrow)
  4176 
  4177 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  4178 textcomp package)
  4179 
  4180 
  4181 
  4182 New in Isabelle2002 (March 2002)
  4183 --------------------------------
  4184 
  4185 *** Document preparation ***
  4186 
  4187 * greatly simplified document preparation setup, including more
  4188 graceful interpretation of isatool usedir -i/-d/-D options, and more
  4189 instructive isatool mkdir; users should basically be able to get
  4190 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  4191 users may run a separate document processing stage manually like this:
  4192 "isatool usedir -D output HOL Test && isatool document Test/output";
  4193 
  4194 * theory dependency graph may now be incorporated into documents;
  4195 isatool usedir -g true will produce session_graph.eps/.pdf for use
  4196 with \includegraphics of LaTeX;
  4197 
  4198 * proper spacing of consecutive markup elements, especially text
  4199 blocks after section headings;
  4200 
  4201 * support bold style (for single symbols only), input syntax is like
  4202 this: "\<^bold>\<alpha>" or "\<^bold>A";
  4203 
  4204 * \<bullet> is now output as bold \cdot by default, which looks much
  4205 better in printed text;
  4206 
  4207 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  4208 note that these symbols are currently unavailable in Proof General /
  4209 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  4210 
  4211 * isatool latex no longer depends on changed TEXINPUTS, instead
  4212 isatool document copies the Isabelle style files to the target
  4213 location;
  4214 
  4215 
  4216 *** Isar ***
  4217 
  4218 * Pure/Provers: improved proof by cases and induction;
  4219   - 'case' command admits impromptu naming of parameters (such as
  4220     "case (Suc n)");
  4221   - 'induct' method divinates rule instantiation from the inductive
  4222     claim; no longer requires excessive ?P bindings for proper
  4223     instantiation of cases;
  4224   - 'induct' method properly enumerates all possibilities of set/type
  4225     rules; as a consequence facts may be also passed through *type*
  4226     rules without further ado;
  4227   - 'induct' method now derives symbolic cases from the *rulified*
  4228     rule (before it used to rulify cases stemming from the internal
  4229     atomized version); this means that the context of a non-atomic
  4230     statement becomes is included in the hypothesis, avoiding the
  4231     slightly cumbersome show "PROP ?case" form;
  4232   - 'induct' may now use elim-style induction rules without chaining
  4233     facts, using ``missing'' premises from the goal state; this allows
  4234     rules stemming from inductive sets to be applied in unstructured
  4235     scripts, while still benefitting from proper handling of non-atomic
  4236     statements; NB: major inductive premises need to be put first, all
  4237     the rest of the goal is passed through the induction;
  4238   - 'induct' proper support for mutual induction involving non-atomic
  4239     rule statements (uses the new concept of simultaneous goals, see
  4240     below);
  4241   - append all possible rule selections, but only use the first
  4242     success (no backtracking);
  4243   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  4244   - undeclared rule case names default to numbers 1, 2, 3, ...;
  4245   - added 'print_induct_rules' (covered by help item in recent Proof
  4246     General versions);
  4247   - moved induct/cases attributes to Pure, methods to Provers;
  4248   - generic method setup instantiated for FOL and HOL;
  4249 
  4250 * Pure: support multiple simultaneous goal statements, for example
  4251 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  4252 meta-level mechanism, this acts as if several individual goals had
  4253 been stated separately; in particular common proof methods need to be
  4254 repeated in order to cover all claims; note that a single elimination
  4255 step is *not* sufficient to establish the two conjunctions, so this
  4256 fails:
  4257 
  4258   assume "A & B" then have A and B ..   (*".." fails*)
  4259 
  4260 better use "obtain" in situations as above; alternative refer to
  4261 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  4262 
  4263 * Pure: proper integration with ``locales''; unlike the original
  4264 version by Florian Kammller, Isar locales package high-level proof
  4265 contexts rather than raw logical ones (e.g. we admit to include
  4266 attributes everywhere); operations on locales include merge and
  4267 rename; support for implicit arguments (``structures''); simultaneous
  4268 type-inference over imports and text; see also HOL/ex/Locales.thy for
  4269 some examples;
  4270 
  4271 * Pure: the following commands have been ``localized'', supporting a
  4272 target locale specification "(in name)": 'lemma', 'theorem',
  4273 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  4274 stored both within the locale and at the theory level (exported and
  4275 qualified by the locale name);
  4276 
  4277 * Pure: theory goals may now be specified in ``long'' form, with
  4278 ad-hoc contexts consisting of arbitrary locale elements. for example
  4279 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  4280 definitions may be given, too); the result is a meta-level rule with
  4281 the context elements being discharged in the obvious way;
  4282 
  4283 * Pure: new proof command 'using' allows to augment currently used
  4284 facts after a goal statement ('using' is syntactically analogous to
  4285 'apply', but acts on the goal's facts only); this allows chained facts
  4286 to be separated into parts given before and after a claim, as in
  4287 ``from a and b have C using d and e <proof>'';
  4288 
  4289 * Pure: renamed "antecedent" case to "rule_context";
  4290 
  4291 * Pure: new 'judgment' command records explicit information about the
  4292 object-logic embedding (used by several tools internally); no longer
  4293 use hard-wired "Trueprop";
  4294 
  4295 * Pure: added 'corollary' command;
  4296 
  4297 * Pure: fixed 'token_translation' command;
  4298 
  4299 * Pure: removed obsolete 'exported' attribute;
  4300 
  4301 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  4302 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  4303 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  4304 
  4305 * Pure: method 'atomize' presents local goal premises as object-level
  4306 statements (atomic meta-level propositions); setup controlled via
  4307 rewrite rules declarations of 'atomize' attribute; example
  4308 application: 'induct' method with proper rule statements in improper
  4309 proof *scripts*;
  4310 
  4311 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  4312 now consider the syntactic context of assumptions, giving a better
  4313 chance to get type-inference of the arguments right (this is
  4314 especially important for locales);
  4315 
  4316 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  4317 mode;
  4318 
  4319 * Pure/obtain: the formal conclusion "thesis", being marked as
  4320 ``internal'', may no longer be reference directly in the text;
  4321 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  4322 situations;
  4323 
  4324 * Pure: generic 'sym' attribute which declares a rule both as pure
  4325 'elim?' and for the 'symmetric' operation;
  4326 
  4327 * Pure: marginal comments ``--'' may now occur just anywhere in the
  4328 text; the fixed correlation with particular command syntax has been
  4329 discontinued;
  4330 
  4331 * Pure: new method 'rules' is particularly well-suited for proof
  4332 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  4333 but often produces more compact proof terms with less detours;
  4334 
  4335 * Pure/Provers/classical: simplified integration with pure rule
  4336 attributes and methods; the classical "intro?/elim?/dest?"
  4337 declarations coincide with the pure ones; the "rule" method no longer
  4338 includes classically swapped intros; "intro" and "elim" methods no
  4339 longer pick rules from the context; also got rid of ML declarations
  4340 AddXIs/AddXEs/AddXDs; all of this has some potential for
  4341 INCOMPATIBILITY;
  4342 
  4343 * Provers/classical: attribute 'swapped' produces classical inversions
  4344 of introduction rules;
  4345 
  4346 * Provers/simplifier: 'simplified' attribute may refer to explicit
  4347 rules instead of full simplifier context; 'iff' attribute handles
  4348 conditional rules;
  4349 
  4350 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  4351 
  4352 * HOL: 'recdef' now fails on unfinished automated proofs, use
  4353 "(permissive)" option to recover old behavior;
  4354 
  4355 * HOL: 'inductive' no longer features separate (collective) attributes
  4356 for 'intros' (was found too confusing);
  4357 
  4358 * HOL: properly declared induction rules less_induct and
  4359 wf_induct_rule;
  4360 
  4361 
  4362 *** HOL ***
  4363 
  4364 * HOL: moved over to sane numeral syntax; the new policy is as
  4365 follows:
  4366 
  4367   - 0 and 1 are polymorphic constants, which are defined on any
  4368   numeric type (nat, int, real etc.);
  4369 
  4370   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  4371   binary representation internally;
  4372 
  4373   - type nat has special constructor Suc, and generally prefers Suc 0
  4374   over 1::nat and Suc (Suc 0) over 2::nat;
  4375 
  4376 This change may cause significant problems of INCOMPATIBILITY; here
  4377 are some hints on converting existing sources:
  4378 
  4379   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  4380   entities, so expressions involving "-" (unary or binary minus) need
  4381   to be spaced properly;
  4382 
  4383   - existing occurrences of "1" may need to be constraint "1::nat" or
  4384   even replaced by Suc 0; similar for old "2";
  4385 
  4386   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  4387 
  4388   - remove all special provisions on numerals in proofs;
  4389 
  4390 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  4391 representation (depends on bin_arith_simps in the default context);
  4392 
  4393 * HOL: symbolic syntax for x^2 (numeral 2);
  4394 
  4395 * HOL: the class of all HOL types is now called "type" rather than
  4396 "term"; INCOMPATIBILITY, need to adapt references to this type class
  4397 in axclass/classes, instance/arities, and (usually rare) occurrences
  4398 in typings (of consts etc.); internally the class is called
  4399 "HOL.type", ML programs should refer to HOLogic.typeS;
  4400 
  4401 * HOL/record package improvements:
  4402   - new derived operations "fields" to build a partial record section,
  4403     "extend" to promote a fixed record to a record scheme, and
  4404     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  4405     declared as simp by default;
  4406   - shared operations ("more", "fields", etc.) now need to be always
  4407     qualified) --- potential INCOMPATIBILITY;
  4408   - removed "make_scheme" operations (use "make" with "extend") --
  4409     INCOMPATIBILITY;
  4410   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  4411   - provides cases/induct rules for use with corresponding Isar
  4412     methods (for concrete records, record schemes, concrete more
  4413     parts, and schematic more parts -- in that order);
  4414   - internal definitions directly based on a light-weight abstract
  4415     theory of product types over typedef rather than datatype;
  4416 
  4417 * HOL: generic code generator for generating executable ML code from
  4418 specifications; specific support for HOL constructs such as inductive
  4419 datatypes and sets, as well as recursive functions; can be invoked
  4420 via 'generate_code' theory section;
  4421 
  4422 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  4423 
  4424 * HOL: consolidated and renamed several theories.  In particular:
  4425         Ord.thy has been absorbed into HOL.thy
  4426         String.thy has been absorbed into List.thy
  4427 
  4428 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  4429 (beware of argument permutation!);
  4430 
  4431 * HOL: linorder_less_split superseded by linorder_cases;
  4432 
  4433 * HOL/List: "nodups" renamed to "distinct";
  4434 
  4435 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  4436 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  4437   - Ex_def has changed, now need to use some_eq_ex
  4438 
  4439 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  4440 in this (rare) case use:
  4441 
  4442   delSWrapper "split_all_tac"
  4443   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  4444 
  4445 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  4446 MAY FAIL;
  4447 
  4448 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  4449 Isabelle's type classes, ^ on functions and relations has too general
  4450 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  4451 necessary to attach explicit type constraints;
  4452 
  4453 * HOL/Relation: the prefix name of the infix "O" has been changed from
  4454 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  4455 renamed accordingly (eg "compI" -> "rel_compI").
  4456 
  4457 * HOL: syntax translations now work properly with numerals and records
  4458 expressions;
  4459 
  4460 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  4461 of "lam" -- INCOMPATIBILITY;
  4462 
  4463 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  4464 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  4465 renamed "Product_Type.unit";
  4466 
  4467 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  4468 
  4469 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  4470 the "cases" method);
  4471 
  4472 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  4473 Florian Kammller);
  4474 
  4475 * HOL/IMP: updated and converted to new-style theory format; several
  4476 parts turned into readable document, with proper Isar proof texts and
  4477 some explanations (by Gerwin Klein);
  4478 
  4479 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  4480 
  4481 * HOL-Hyperreal is now a logic image;
  4482 
  4483 
  4484 *** HOLCF ***
  4485 
  4486 * Isar: consts/constdefs supports mixfix syntax for continuous
  4487 operations;
  4488 
  4489 * Isar: domain package adapted to new-style theory format, e.g. see
  4490 HOLCF/ex/Dnat.thy;
  4491 
  4492 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  4493 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  4494 lift.induct_tac, always use UU instead of Undef;
  4495 
  4496 * HOLCF/IMP: updated and converted to new-style theory;
  4497 
  4498 
  4499 *** ZF ***
  4500 
  4501 * Isar: proper integration of logic-specific tools and packages,
  4502 including theory commands '(co)inductive', '(co)datatype',
  4503 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  4504 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  4505 
  4506 * theory Main no longer includes AC; for the Axiom of Choice, base
  4507 your theory on Main_ZFC;
  4508 
  4509 * the integer library now covers quotients and remainders, with many
  4510 laws relating division to addition, multiplication, etc.;
  4511 
  4512 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  4513 typeless version of the formalism;
  4514 
  4515 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  4516 format;
  4517 
  4518 * ZF/Induct: new directory for examples of inductive definitions,
  4519 including theory Multiset for multiset orderings; converted to
  4520 new-style theory format;
  4521 
  4522 * ZF: many new theorems about lists, ordinals, etc.;
  4523 
  4524 
  4525 *** General ***
  4526 
  4527 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  4528 variable proof controls level of detail: 0 = no proofs (only oracle
  4529 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  4530 also ref manual for further ML interfaces;
  4531 
  4532 * Pure/axclass: removed obsolete ML interface
  4533 goal_subclass/goal_arity;
  4534 
  4535 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  4536 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  4537 separate tokens, so expressions involving minus need to be spaced
  4538 properly;
  4539 
  4540 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  4541 rather than "infixl" or "infixr";
  4542 
  4543 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  4544 sort constraint specifications in type inference; e.g. "x::_::foo"
  4545 ensures that the type of "x" is of sort "foo" (but not necessarily a
  4546 type variable);
  4547 
  4548 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  4549 control output of nested => (types); the default behavior is
  4550 "type_brackets";
  4551 
  4552 * Pure/syntax: builtin parse translation for "_constify" turns valued
  4553 tokens into AST constants;
  4554 
  4555 * Pure/syntax: prefer later declarations of translations and print
  4556 translation functions; potential INCOMPATIBILITY: need to reverse
  4557 multiple declarations for same syntax element constant;
  4558 
  4559 * Pure/show_hyps reset by default (in accordance to existing Isar
  4560 practice);
  4561 
  4562 * Provers/classical: renamed addaltern to addafter, addSaltern to
  4563 addSafter;
  4564 
  4565 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  4566 as well;
  4567 
  4568 * system: tested support for MacOS X; should be able to get Isabelle +
  4569 Proof General to work in a plain Terminal after installing Poly/ML
  4570 (e.g. from the Isabelle distribution area) and GNU bash alone
  4571 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  4572 support requires further installations, e.g. from
  4573 http://fink.sourceforge.net/);
  4574 
  4575 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  4576 
  4577 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  4578 of 40 MB), cf. ML_OPTIONS;
  4579 
  4580 * system: Proof General keywords specification is now part of the
  4581 Isabelle distribution (see etc/isar-keywords.el);
  4582 
  4583 * system: support for persistent Proof General sessions (refrain from
  4584 outdating all loaded theories on startup); user may create writable
  4585 logic images like this: ``isabelle -q HOL Test'';
  4586 
  4587 * system: smart selection of Isabelle process versus Isabelle
  4588 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  4589 run both "isabelle" and "Isabelle" even if file names are badly
  4590 damaged (executable inspects the case of the first letter of its own
  4591 name); added separate "isabelle-process" and "isabelle-interface";
  4592 
  4593 * system: refrain from any attempt at filtering input streams; no
  4594 longer support ``8bit'' encoding of old isabelle font, instead proper
  4595 iso-latin characters may now be used; the related isatools
  4596 "symbolinput" and "nonascii" have disappeared as well;
  4597 
  4598 * system: removed old "xterm" interface (the print modes "xterm" and
  4599 "xterm_color" are still available for direct use in a suitable
  4600 terminal);
  4601 
  4602 
  4603 
  4604 New in Isabelle99-2 (February 2001)
  4605 -----------------------------------
  4606 
  4607 *** Overview of INCOMPATIBILITIES ***
  4608 
  4609 * HOL: please note that theories in the Library and elsewhere often use the
  4610 new-style (Isar) format; to refer to their theorems in an ML script you must
  4611 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  4612 
  4613 * HOL: inductive package no longer splits induction rule aggressively,
  4614 but only as far as specified by the introductions given; the old
  4615 format may be recovered via ML function complete_split_rule or attribute
  4616 'split_rule (complete)';
  4617 
  4618 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  4619 gfp_Tarski to gfp_unfold;
  4620 
  4621 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  4622 
  4623 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  4624 relation); infix "^^" has been renamed "``"; infix "``" has been
  4625 renamed "`"; "univalent" has been renamed "single_valued";
  4626 
  4627 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  4628 operation;
  4629 
  4630 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  4631 
  4632 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  4633 
  4634 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  4635 consequence, it is no longer monotonic wrt. the local goal context
  4636 (which is now passed through the inductive cases);
  4637 
  4638 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  4639 \<gg> to \<ggreater>;
  4640 
  4641 
  4642 *** Document preparation ***
  4643 
  4644 * \isabellestyle{NAME} selects version of Isabelle output (currently
  4645 available: are "it" for near math-mode best-style output, "sl" for
  4646 slanted text style, and "tt" for plain type-writer; if no
  4647 \isabellestyle command is given, output is according to slanted
  4648 type-writer);
  4649 
  4650 * support sub/super scripts (for single symbols only), input syntax is
  4651 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  4652 
  4653 * some more standard symbols; see Appendix A of the system manual for
  4654 the complete list of symbols defined in isabellesym.sty;
  4655 
  4656 * improved isabelle style files; more abstract symbol implementation
  4657 (should now use \isamath{...} and \isatext{...} in custom symbol
  4658 definitions);
  4659 
  4660 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  4661 state; Note that presentation of goal states does not conform to
  4662 actual human-readable proof documents.  Please do not include goal
  4663 states into document output unless you really know what you are doing!
  4664 
  4665 * proper indentation of antiquoted output with proportional LaTeX
  4666 fonts;
  4667 
  4668 * no_document ML operator temporarily disables LaTeX document
  4669 generation;
  4670 
  4671 * isatool unsymbolize tunes sources for plain ASCII communication;
  4672 
  4673 
  4674 *** Isar ***
  4675 
  4676 * Pure: Isar now suffers initial goal statements to contain unbound
  4677 schematic variables (this does not conform to actual readable proof
  4678 documents, due to unpredictable outcome and non-compositional proof
  4679 checking); users who know what they are doing may use schematic goals
  4680 for Prolog-style synthesis of proven results;
  4681 
  4682 * Pure: assumption method (an implicit finishing) now handles actual
  4683 rules as well;
  4684 
  4685 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4686 initial goal, declare "that" only as Pure intro (only for single
  4687 steps); the "that" rule assumption may now be involved in implicit
  4688 finishing, thus ".." becomes a feasible for trivial obtains;
  4689 
  4690 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4691 instance proofs may be performed by "..";
  4692 
  4693 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4694 statements as well;
  4695 
  4696 * Pure: more robust selection of calculational rules;
  4697 
  4698 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4699 rule (as well as the assumption rule);
  4700 
  4701 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4702 lemmas, using the graph browser tool;
  4703 
  4704 * Pure: predict failure of "show" in interactive mode;
  4705 
  4706 * Pure: 'thms_containing' now takes actual terms as arguments;
  4707 
  4708 * HOL: improved method 'induct' --- now handles non-atomic goals
  4709 (potential INCOMPATIBILITY); tuned error handling;
  4710 
  4711 * HOL: cases and induct rules now provide explicit hints about the
  4712 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4713 any remaining facts are inserted into the goal verbatim;
  4714 
  4715 * HOL: local contexts (aka cases) may now contain term bindings as
  4716 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4717 the result to be shown in each case;
  4718 
  4719 * HOL: added 'recdef_tc' command;
  4720 
  4721 * isatool convert assists in eliminating legacy ML scripts;
  4722 
  4723 
  4724 *** HOL ***
  4725 
  4726 * HOL/Library: a collection of generic theories to be used together
  4727 with main HOL; the theory loader path already includes this directory
  4728 by default; the following existing theories have been moved here:
  4729 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4730 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4731 
  4732 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4733 modelling and verification task performed in Isabelle/HOL +
  4734 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4735 
  4736 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4737 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4738 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4739 'domain', this makes the theory consistent with mathematical
  4740 literature;
  4741 
  4742 * HOL basics: added overloaded operations "inverse" and "divide"
  4743 (infix "/"), syntax for generic "abs" operation, generic summation
  4744 operator \<Sum>;
  4745 
  4746 * HOL/typedef: simplified package, provide more useful rules (see also
  4747 HOL/subset.thy);
  4748 
  4749 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4750 now expressed as a proper nested rule (old-style tactic scripts may
  4751 require atomize_strip_tac to cope with non-atomic premises);
  4752 
  4753 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4754 to "split_conv" (old name still available for compatibility);
  4755 
  4756 * HOL: improved concrete syntax for strings (e.g. allows translation
  4757 rules with string literals);
  4758 
  4759 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4760  and Fleuriot's mechanization of analysis, including the transcendental
  4761  functions for the reals;
  4762 
  4763 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4764 
  4765 
  4766 *** CTT ***
  4767 
  4768 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4769 "lam" is displayed as TWO lambda-symbols
  4770 
  4771 * CTT: theory Main now available, containing everything (that is, Bool
  4772 and Arith);
  4773 
  4774 
  4775 *** General ***
  4776 
  4777 * Pure: the Simplifier has been implemented properly as a derived rule
  4778 outside of the actual kernel (at last!); the overall performance
  4779 penalty in practical applications is about 50%, while reliability of
  4780 the Isabelle inference kernel has been greatly improved;
  4781 
  4782 * print modes "brackets" and "no_brackets" control output of nested =>
  4783 (types) and ==> (props); the default behaviour is "brackets";
  4784 
  4785 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4786 as assumptions as well;
  4787 
  4788 * system: support Poly/ML 4.0;
  4789 
  4790 * system: isatool install handles KDE version 1 or 2;
  4791 
  4792 
  4793 
  4794 New in Isabelle99-1 (October 2000)
  4795 ----------------------------------
  4796 
  4797 *** Overview of INCOMPATIBILITIES ***
  4798 
  4799 * HOL: simplification of natural numbers is much changed; to partly
  4800 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4801 issue the following ML commands:
  4802 
  4803   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4804   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4805 
  4806 * HOL: simplification no longer dives into case-expressions; this is
  4807 controlled by "t.weak_case_cong" for each datatype t;
  4808 
  4809 * HOL: nat_less_induct renamed to less_induct;
  4810 
  4811 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4812 fixsome to patch .thy and .ML sources automatically;
  4813 
  4814   select_equality  -> some_equality
  4815   select_eq_Ex     -> some_eq_ex
  4816   selectI2EX       -> someI2_ex
  4817   selectI2         -> someI2
  4818   selectI          -> someI
  4819   select1_equality -> some1_equality
  4820   Eps_sym_eq       -> some_sym_eq_trivial
  4821   Eps_eq           -> some_eq_trivial
  4822 
  4823 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4824 
  4825 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4826 instead);
  4827 
  4828 * HOL: the recursion equations generated by 'recdef' are now called
  4829 f.simps instead of f.rules;
  4830 
  4831 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4832 
  4833 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4834 sometimes be needed;
  4835 
  4836 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4837 
  4838 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4839 
  4840 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4841 product is now "<*>" instead of "Times"; the lexicographic product is
  4842 now "<*lex*>" instead of "**";
  4843 
  4844 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4845 of main HOL, but was unused); better use HOL's datatype package;
  4846 
  4847 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4848 the old syntax may be recovered as follows:
  4849 
  4850   syntax (symbols)
  4851     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4852       (infixl "\\<oplus>" 100)
  4853 
  4854 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4855 
  4856 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4857 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4858 internally;
  4859 
  4860 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4861 changed from A/r to A//r;
  4862 
  4863 * ZF: new treatment of arithmetic (nat & int) may break some old
  4864 proofs;
  4865 
  4866 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4867 rulify -> rule_format, elimify -> elim_format, ...);
  4868 
  4869 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4870 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4871 should have to change intro!! to intro? only); replaced "delrule" by
  4872 "rule del";
  4873 
  4874 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4875 
  4876 * Provers: strengthened force_tac by using new first_best_tac;
  4877 
  4878 * LaTeX document preparation: several changes of isabelle.sty (see
  4879 lib/texinputs);
  4880 
  4881 
  4882 *** Document preparation ***
  4883 
  4884 * formal comments (text blocks etc.) in new-style theories may now
  4885 contain antiquotations of thm/prop/term/typ/text to be presented
  4886 according to latex print mode; concrete syntax is like this:
  4887 @{term[show_types] "f(x) = a + x"};
  4888 
  4889 * isatool mkdir provides easy setup of Isabelle session directories,
  4890 including proper document sources;
  4891 
  4892 * generated LaTeX sources are now deleted after successful run
  4893 (isatool document -c); may retain a copy somewhere else via -D option
  4894 of isatool usedir;
  4895 
  4896 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4897 style files, achieving self-contained LaTeX sources and simplifying
  4898 LaTeX debugging;
  4899 
  4900 * old-style theories now produce (crude) LaTeX output as well;
  4901 
  4902 * browser info session directories are now self-contained (may be put
  4903 on WWW server seperately); improved graphs of nested sessions; removed
  4904 graph for 'all sessions';
  4905 
  4906 * several improvements in isabelle style files; \isabellestyle{it}
  4907 produces fake math mode output; \isamarkupheader is now \section by
  4908 default; see lib/texinputs/isabelle.sty etc.;
  4909 
  4910 
  4911 *** Isar ***
  4912 
  4913 * Isar/Pure: local results and corresponding term bindings are now
  4914 subject to Hindley-Milner polymorphism (similar to ML); this
  4915 accommodates incremental type-inference very nicely;
  4916 
  4917 * Isar/Pure: new derived language element 'obtain' supports
  4918 generalized existence reasoning;
  4919 
  4920 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4921 support accumulation of results, without applying any rules yet;
  4922 useful to collect intermediate results without explicit name
  4923 references, and for use with transitivity rules with more than 2
  4924 premises;
  4925 
  4926 * Isar/Pure: scalable support for case-analysis type proofs: new
  4927 'case' language element refers to local contexts symbolically, as
  4928 produced by certain proof methods; internally, case names are attached
  4929 to theorems as "tags";
  4930 
  4931 * Isar/Pure: theory command 'hide' removes declarations from
  4932 class/type/const name spaces;
  4933 
  4934 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4935 indicate potential overloading;
  4936 
  4937 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4938 
  4939 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4940 "{a,b,c}" instead of {a,b,c};
  4941 
  4942 * Isar/Pure now provides its own version of intro/elim/dest
  4943 attributes; useful for building new logics, but beware of confusion
  4944 with the version in Provers/classical;
  4945 
  4946 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4947 case name 'antecedent';
  4948 
  4949 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4950 to the current context is now done automatically);
  4951 
  4952 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4953 for definining proof methods in ML;
  4954 
  4955 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4956 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4957 most cases, one should have to change intro!! to intro? only);
  4958 replaced "delrule" by "rule del";
  4959 
  4960 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4961 'symmetric' attribute (the latter supercedes [RS sym]);
  4962 
  4963 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4964 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4965 well (including splits);
  4966 
  4967 * Isar/Provers: Simplifier and Classical methods now support all kind
  4968 of modifiers used in the past, including 'cong', 'iff', etc.
  4969 
  4970 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4971 of Simplifier and Classical reasoner);
  4972 
  4973 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4974 now support named cases; major packages (inductive, datatype, primrec,
  4975 recdef) support case names and properly name parameters;
  4976 
  4977 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4978 monotonicity conditions are extracted to be proven at end of
  4979 calculations;
  4980 
  4981 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4982 method anyway;
  4983 
  4984 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4985 split_if split_if_asm; datatype package provides theorems foo.splits =
  4986 foo.split foo.split_asm for each datatype;
  4987 
  4988 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4989 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4990 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4991 use "(cases (simplified))" method in proper proof texts);
  4992 
  4993 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4994 
  4995 * Isar: names of theorems etc. may be natural numbers as well;
  4996 
  4997 * Isar: 'pr' command: optional arguments for goals_limit and
  4998 ProofContext.prems_limit; no longer prints theory contexts, but only
  4999 proof states;
  5000 
  5001 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  5002 additional print modes to be specified; e.g. "pr(latex)" will print
  5003 proof state according to the Isabelle LaTeX style;
  5004 
  5005 * Isar: improved support for emulating tactic scripts, including proof
  5006 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  5007 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  5008 (for HOL datatypes);
  5009 
  5010 * Isar: simplified (more robust) goal selection of proof methods: 1st
  5011 goal, all goals, or explicit goal specifier (tactic emulation); thus
  5012 'proof method scripts' have to be in depth-first order;
  5013 
  5014 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  5015 
  5016 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  5017 should instead use individual commands for printing items
  5018 (print_commands, print_methods etc.);
  5019 
  5020 * Isar: added 'nothing' --- the empty list of theorems;
  5021 
  5022 
  5023 *** HOL ***
  5024 
  5025 * HOL/MicroJava: formalization of a fragment of Java, together with a
  5026 corresponding virtual machine and a specification of its bytecode
  5027 verifier and a lightweight bytecode verifier, including proofs of
  5028 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  5029 Cornelia Pusch (see also the homepage of project Bali at
  5030 http://isabelle.in.tum.de/Bali/);
  5031 
  5032 * HOL/Algebra: new theory of rings and univariate polynomials, by
  5033 Clemens Ballarin;
  5034 
  5035 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  5036 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  5037 Rasmussen;
  5038 
  5039 * HOL/Lattice: fundamental concepts of lattice theory and order
  5040 structures, including duals, properties of bounds versus algebraic
  5041 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  5042 Theorem for complete lattices etc.; may also serve as a demonstration
  5043 for abstract algebraic reasoning using axiomatic type classes, and
  5044 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  5045 
  5046 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  5047 von Oheimb;
  5048 
  5049 * HOL/IMPP: extension of IMP with local variables and mutually
  5050 recursive procedures, by David von Oheimb;
  5051 
  5052 * HOL/Lambda: converted into new-style theory and document;
  5053 
  5054 * HOL/ex/Multiquote: example of multiple nested quotations and
  5055 anti-quotations -- basically a generalized version of de-Bruijn
  5056 representation; very useful in avoiding lifting of operations;
  5057 
  5058 * HOL/record: added general record equality rule to simpset; fixed
  5059 select-update simplification procedure to handle extended records as
  5060 well; admit "r" as field name;
  5061 
  5062 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  5063 other numeric types and also as the identity of groups, rings, etc.;
  5064 
  5065 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  5066 Types nat and int belong to this axclass;
  5067 
  5068 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  5069    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  5070    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  5071   two terms #m*u and #n*u are replaced by #(m+n)*u
  5072     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  5073   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  5074     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  5075 
  5076 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  5077 powerful prover for predicate logic but knows nothing of clasets; see
  5078 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  5079 
  5080 * HOL: new version of "case_tac" subsumes both boolean case split and
  5081 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  5082 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  5083 
  5084 * HOL: simplification no longer dives into case-expressions: only the
  5085 selector expression is simplified, but not the remaining arms; to
  5086 enable full simplification of case-expressions for datatype t, you may
  5087 remove t.weak_case_cong from the simpset, either globally (Delcongs
  5088 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  5089 
  5090 * HOL/recdef: the recursion equations generated by 'recdef' for
  5091 function 'f' are now called f.simps instead of f.rules; if all
  5092 termination conditions are proved automatically, these simplification
  5093 rules are added to the simpset, as in primrec; rules may be named
  5094 individually as well, resulting in a separate list of theorems for
  5095 each equation;
  5096 
  5097 * HOL/While is a new theory that provides a while-combinator. It
  5098 permits the definition of tail-recursive functions without the
  5099 provision of a termination measure. The latter is necessary once the
  5100 invariant proof rule for while is applied.
  5101 
  5102 * HOL: new (overloaded) notation for the set of elements below/above
  5103 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  5104 
  5105 * HOL: theorems impI, allI, ballI bound as "strip";
  5106 
  5107 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  5108 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  5109 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  5110 
  5111 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  5112 
  5113 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  5114 main HOL, but was unused);
  5115 
  5116 * HOL: fewer consts declared as global (e.g. have to refer to
  5117 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  5118 
  5119 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  5120 in case of overlap with user translations (e.g. judgements over
  5121 tuples); (note that the underlying logical represenation is still
  5122 bogus);
  5123 
  5124 
  5125 *** ZF ***
  5126 
  5127 * ZF: simplification automatically cancels common terms in arithmetic
  5128 expressions over nat and int;
  5129 
  5130 * ZF: new treatment of nat to minimize type-checking: all operators
  5131 coerce their operands to a natural number using the function natify,
  5132 making the algebraic laws unconditional;
  5133 
  5134 * ZF: as above, for int: operators coerce their operands to an integer
  5135 using the function intify;
  5136 
  5137 * ZF: the integer library now contains many of the usual laws for the
  5138 orderings, including $<=, and monotonicity laws for $+ and $*;
  5139 
  5140 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  5141 simplification;
  5142 
  5143 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  5144 to the simplifier and classical reasoner simultaneously;
  5145 
  5146 
  5147 *** General ***
  5148 
  5149 * Provers: blast_tac now handles actual object-logic rules as
  5150 assumptions; note that auto_tac uses blast_tac internally as well;
  5151 
  5152 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  5153 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  5154 
  5155 * Provers: delrules now handles destruct rules as well (no longer need
  5156 explicit make_elim);
  5157 
  5158 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  5159   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5160 use instead the strong form,
  5161   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  5162 in HOL, FOL and ZF the function cla_make_elim will create such rules
  5163 from destruct-rules;
  5164 
  5165 * Provers: Simplifier.easy_setup provides a fast path to basic
  5166 Simplifier setup for new object-logics;
  5167 
  5168 * Pure: AST translation rules no longer require constant head on LHS;
  5169 
  5170 * Pure: improved name spaces: ambiguous output is qualified; support
  5171 for hiding of names;
  5172 
  5173 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  5174 XSYMBOL_HOME; no longer need to do manual configuration in most
  5175 situations;
  5176 
  5177 * system: compression of ML heaps images may now be controlled via -c
  5178 option of isabelle and isatool usedir (currently only observed by
  5179 Poly/ML);
  5180 
  5181 * system: isatool installfonts may handle X-Symbol fonts as well (very
  5182 useful for remote X11);
  5183 
  5184 * system: provide TAGS file for Isabelle sources;
  5185 
  5186 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  5187 order;
  5188 
  5189 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  5190 timing flag supersedes proof_timing and Toplevel.trace;
  5191 
  5192 * ML: new combinators |>> and |>>> for incremental transformations
  5193 with secondary results (e.g. certain theory extensions):
  5194 
  5195 * ML: PureThy.add_defs gets additional argument to indicate potential
  5196 overloading (usually false);
  5197 
  5198 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  5199 results;
  5200 
  5201 
  5202 
  5203 New in Isabelle99 (October 1999)
  5204 --------------------------------
  5205 
  5206 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5207 
  5208 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  5209 are no longer simplified.  (This allows the simplifier to unfold recursive
  5210 functional programs.)  To restore the old behaviour, declare
  5211 
  5212     Delcongs [if_weak_cong];
  5213 
  5214 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  5215 complement;
  5216 
  5217 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  5218 
  5219 * HOL/datatype: mutual_induct_tac no longer exists --
  5220   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  5221 
  5222 * HOL/typedef: fixed type inference for representing set; type
  5223 arguments now have to occur explicitly on the rhs as type constraints;
  5224 
  5225 * ZF: The con_defs part of an inductive definition may no longer refer
  5226 to constants declared in the same theory;
  5227 
  5228 * HOL, ZF: the function mk_cases, generated by the inductive
  5229 definition package, has lost an argument.  To simplify its result, it
  5230 uses the default simpset instead of a supplied list of theorems.
  5231 
  5232 * HOL/List: the constructors of type list are now Nil and Cons;
  5233 
  5234 * Simplifier: the type of the infix ML functions
  5235         setSSolver addSSolver setSolver addSolver
  5236 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  5237 for packaging solvers. A solver is created via
  5238         mk_solver: string -> (thm list -> int -> tactic) -> solver
  5239 where the string argument is only a comment.
  5240 
  5241 
  5242 *** Proof tools ***
  5243 
  5244 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  5245 decision procedure for linear arithmetic. Currently it is used for
  5246 types `nat', `int', and `real' in HOL (see below); it can, should and
  5247 will be instantiated for other types and logics as well.
  5248 
  5249 * The simplifier now accepts rewrite rules with flexible heads, eg
  5250      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  5251   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  5252   matching.
  5253 
  5254 
  5255 *** General ***
  5256 
  5257 * New Isabelle/Isar subsystem provides an alternative to traditional
  5258 tactical theorem proving; together with the ProofGeneral/isar user
  5259 interface it offers an interactive environment for developing human
  5260 readable proof documents (Isar == Intelligible semi-automated
  5261 reasoning); for further information see isatool doc isar-ref,
  5262 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  5263 
  5264 * improved and simplified presentation of theories: better HTML markup
  5265 (including colors), graph views in several sizes; isatool usedir now
  5266 provides a proper interface for user theories (via -P option); actual
  5267 document preparation based on (PDF)LaTeX is available as well (for
  5268 new-style theories only); see isatool doc system for more information;
  5269 
  5270 * native support for Proof General, both for classic Isabelle and
  5271 Isabelle/Isar;
  5272 
  5273 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  5274 using the graph browser tool;
  5275 
  5276 * Isabelle manuals now also available as PDF;
  5277 
  5278 * theory loader rewritten from scratch (may not be fully
  5279 bug-compatible); old loadpath variable has been replaced by show_path,
  5280 add_path, del_path, reset_path functions; new operations such as
  5281 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  5282 isatool doc ref);
  5283 
  5284 * improved isatool install: option -k creates KDE application icon,
  5285 option -p DIR installs standalone binaries;
  5286 
  5287 * added ML_PLATFORM setting (useful for cross-platform installations);
  5288 more robust handling of platform specific ML images for SML/NJ;
  5289 
  5290 * the settings environment is now statically scoped, i.e. it is never
  5291 created again in sub-processes invoked from isabelle, isatool, or
  5292 Isabelle;
  5293 
  5294 * path element specification '~~' refers to '$ISABELLE_HOME';
  5295 
  5296 * in locales, the "assumes" and "defines" parts may be omitted if
  5297 empty;
  5298 
  5299 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  5300 long arrows);
  5301 
  5302 * new print_mode "HTML";
  5303 
  5304 * new flag show_tags controls display of tags of theorems (which are
  5305 basically just comments that may be attached by some tools);
  5306 
  5307 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  5308 mode and goal output format:
  5309 
  5310 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  5311 244c244
  5312 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  5313 ---
  5314 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  5315 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  5316 181c181
  5317 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  5318 ---
  5319 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  5320 
  5321 * function bind_thms stores lists of theorems (cf. bind_thm);
  5322 
  5323 * new shorthand tactics ftac, eatac, datac, fatac;
  5324 
  5325 * qed (and friends) now accept "" as result name; in that case the
  5326 theorem is not stored, but proper checks and presentation of the
  5327 result still apply;
  5328 
  5329 * theorem database now also indexes constants "Trueprop", "all",
  5330 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  5331 
  5332 
  5333 *** HOL ***
  5334 
  5335 ** HOL arithmetic **
  5336 
  5337 * There are now decision procedures for linear arithmetic over nat and
  5338 int:
  5339 
  5340 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  5341 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  5342 are treated as atomic; subformulae not involving type `nat' or `int'
  5343 are ignored; quantified subformulae are ignored unless they are
  5344 positive universal or negative existential. The tactic has to be
  5345 invoked by hand and can be a little bit slow. In particular, the
  5346 running time is exponential in the number of occurrences of `min' and
  5347 `max', and `-' on `nat'.
  5348 
  5349 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  5350 (negated) (in)equalities among the premises and the conclusion into
  5351 account (i.e. no compound formulae) and does not know about `min' and
  5352 `max', and `-' on `nat'. It is fast and is used automatically by the
  5353 simplifier.
  5354 
  5355 NB: At the moment, these decision procedures do not cope with mixed
  5356 nat/int formulae where the two parts interact, such as `m < n ==>
  5357 int(m) < int(n)'.
  5358 
  5359 * HOL/Numeral provides a generic theory of numerals (encoded
  5360 efficiently as bit strings); setup for types nat/int/real is in place;
  5361 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  5362 int, existing theories and proof scripts may require a few additional
  5363 type constraints;
  5364 
  5365 * integer division and remainder can now be performed on constant
  5366 arguments;
  5367 
  5368 * many properties of integer multiplication, division and remainder
  5369 are now available;
  5370 
  5371 * An interface to the Stanford Validity Checker (SVC) is available through the
  5372 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  5373 are proved automatically.  SVC must be installed separately, and its results
  5374 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  5375 invocation of the underlying oracle).  For SVC see
  5376   http://verify.stanford.edu/SVC
  5377 
  5378 * IsaMakefile: the HOL-Real target now builds an actual image;
  5379 
  5380 
  5381 ** HOL misc **
  5382 
  5383 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  5384 (in Isabelle/Isar) -- by Gertrud Bauer;
  5385 
  5386 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  5387 analysis for assembly languages with subtypes;
  5388 
  5389 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  5390 -- avoids syntactic ambiguities and treats state, transition, and
  5391 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  5392 changed syntax and (many) tactics;
  5393 
  5394 * HOL/inductive: Now also handles more general introduction rules such
  5395   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  5396   theorems are now maintained within the theory (maintained via the
  5397   "mono" attribute);
  5398 
  5399 * HOL/datatype: Now also handles arbitrarily branching datatypes
  5400   (using function types) such as
  5401 
  5402   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  5403 
  5404 * HOL/record: record_simproc (part of the default simpset) takes care
  5405 of selectors applied to updated records; record_split_tac is no longer
  5406 part of the default claset; update_defs may now be removed from the
  5407 simpset in many cases; COMPATIBILITY: old behavior achieved by
  5408 
  5409   claset_ref () := claset() addSWrapper record_split_wrapper;
  5410   Delsimprocs [record_simproc]
  5411 
  5412 * HOL/typedef: fixed type inference for representing set; type
  5413 arguments now have to occur explicitly on the rhs as type constraints;
  5414 
  5415 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  5416 names rather than an ML expression;
  5417 
  5418 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  5419 supplied later.  Program schemes can be defined, such as
  5420     "While B C s = (if B s then While B C (C s) else s)"
  5421 where the well-founded relation can be chosen after B and C have been given.
  5422 
  5423 * HOL/List: the constructors of type list are now Nil and Cons;
  5424 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  5425 course, ML tools referring to List.list.op # etc. have to be adapted;
  5426 
  5427 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  5428 disabled by default; run isabelle with option -m HOL to get back to
  5429 the original Gordon/HOL-style output;
  5430 
  5431 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  5432 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  5433 
  5434 * HOL basic syntax simplified (more orthogonal): all variants of
  5435 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  5436 Eps operator is provided as well: "SOME x. P[x]";
  5437 
  5438 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  5439 
  5440 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  5441 thus available for user theories;
  5442 
  5443 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  5444 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  5445 time;
  5446 
  5447 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  5448 several times and then mp;
  5449 
  5450 
  5451 *** LK ***
  5452 
  5453 * the notation <<...>> is now available as a notation for sequences of
  5454 formulas;
  5455 
  5456 * the simplifier is now installed
  5457 
  5458 * the axiom system has been generalized (thanks to Soren Heilmann)
  5459 
  5460 * the classical reasoner now has a default rule database
  5461 
  5462 
  5463 *** ZF ***
  5464 
  5465 * new primrec section allows primitive recursive functions to be given
  5466 directly (as in HOL) over datatypes and the natural numbers;
  5467 
  5468 * new tactics induct_tac and exhaust_tac for induction (or case
  5469 analysis) over datatypes and the natural numbers;
  5470 
  5471 * the datatype declaration of type T now defines the recursor T_rec;
  5472 
  5473 * simplification automatically does freeness reasoning for datatype
  5474 constructors;
  5475 
  5476 * automatic type-inference, with AddTCs command to insert new
  5477 type-checking rules;
  5478 
  5479 * datatype introduction rules are now added as Safe Introduction rules
  5480 to the claset;
  5481 
  5482 * the syntax "if P then x else y" is now available in addition to
  5483 if(P,x,y);
  5484 
  5485 
  5486 *** Internal programming interfaces ***
  5487 
  5488 * tuned simplifier trace output; new flag debug_simp;
  5489 
  5490 * structures Vartab / Termtab (instances of TableFun) offer efficient
  5491 tables indexed by indexname_ord / term_ord (compatible with aconv);
  5492 
  5493 * AxClass.axclass_tac lost the theory argument;
  5494 
  5495 * tuned current_goals_markers semantics: begin / end goal avoids
  5496 printing empty lines;
  5497 
  5498 * removed prs and prs_fn hook, which was broken because it did not
  5499 include \n in its semantics, forcing writeln to add one
  5500 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  5501 string -> unit if you really want to output text without newline;
  5502 
  5503 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  5504 plain output, interface builders may have to enable 'isabelle_font'
  5505 mode to get Isabelle font glyphs as before;
  5506 
  5507 * refined token_translation interface; INCOMPATIBILITY: output length
  5508 now of type real instead of int;
  5509 
  5510 * theory loader actions may be traced via new ThyInfo.add_hook
  5511 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  5512 your own database of information attached to *whole* theories -- as
  5513 opposed to intra-theory data slots offered via TheoryDataFun;
  5514 
  5515 * proper handling of dangling sort hypotheses (at last!);
  5516 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  5517 extra sort hypotheses that can be witnessed from the type signature;
  5518 the force_strip_shyps flag is gone, any remaining shyps are simply
  5519 left in the theorem (with a warning issued by strip_shyps_warning);
  5520 
  5521 
  5522 
  5523 New in Isabelle98-1 (October 1998)
  5524 ----------------------------------
  5525 
  5526 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5527 
  5528 * several changes of automated proof tools;
  5529 
  5530 * HOL: major changes to the inductive and datatype packages, including
  5531 some minor incompatibilities of theory syntax;
  5532 
  5533 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  5534 called `inj_on';
  5535 
  5536 * HOL: removed duplicate thms in Arith:
  5537   less_imp_add_less  should be replaced by  trans_less_add1
  5538   le_imp_add_le      should be replaced by  trans_le_add1
  5539 
  5540 * HOL: unary minus is now overloaded (new type constraints may be
  5541 required);
  5542 
  5543 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  5544 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  5545 now taken as an integer constant.
  5546 
  5547 * Pure: ML function 'theory_of' renamed to 'theory';
  5548 
  5549 
  5550 *** Proof tools ***
  5551 
  5552 * Simplifier:
  5553   1. Asm_full_simp_tac is now more aggressive.
  5554      1. It will sometimes reorient premises if that increases their power to
  5555         simplify.
  5556      2. It does no longer proceed strictly from left to right but may also
  5557         rotate premises to achieve further simplification.
  5558      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  5559      old Asm_full_simp_tac in that it does not rotate premises.
  5560   2. The simplifier now knows a little bit about nat-arithmetic.
  5561 
  5562 * Classical reasoner: wrapper mechanism for the classical reasoner now
  5563 allows for selected deletion of wrappers, by introduction of names for
  5564 wrapper functionals.  This implies that addbefore, addSbefore,
  5565 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  5566 and that adding two tactics with the same name overwrites the first
  5567 one (emitting a warning).
  5568   type wrapper = (int -> tactic) -> (int -> tactic)
  5569   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  5570   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  5571   delWrapper, delSWrapper: claset *  string            -> claset
  5572   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  5573 
  5574 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  5575 semantics; addbefore now affects only the unsafe part of step_tac
  5576 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  5577 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  5578 by Force_tac;
  5579 
  5580 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  5581 compWrapper; added safe wrapper (and access functions for it);
  5582 
  5583 * HOL/split_all_tac is now much faster and fails if there is nothing
  5584 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  5585 and the names of the automatically generated variables have changed.
  5586 split_all_tac has moved within claset() from unsafe wrappers to safe
  5587 wrappers, which means that !!-bound variables are split much more
  5588 aggressively, and safe_tac and clarify_tac now split such variables.
  5589 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  5590 Note: the same holds for record_split_tac, which does the job of
  5591 split_all_tac for record fields.
  5592 
  5593 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  5594 permanently to the default simpset using Addsplits just like
  5595 Addsimps. They can be removed via Delsplits just like
  5596 Delsimps. Lower-case versions are also available.
  5597 
  5598 * HOL/Simplifier: The rule split_if is now part of the default
  5599 simpset. This means that the simplifier will eliminate all occurrences
  5600 of if-then-else in the conclusion of a goal. To prevent this, you can
  5601 either remove split_if completely from the default simpset by
  5602 `Delsplits [split_if]' or remove it in a specific call of the
  5603 simplifier using `... delsplits [split_if]'.  You can also add/delete
  5604 other case splitting rules to/from the default simpset: every datatype
  5605 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  5606 t is the name of the datatype).
  5607 
  5608 * Classical reasoner / Simplifier combination: new force_tac (and
  5609 derivatives Force_tac, force) combines rewriting and classical
  5610 reasoning (and whatever other tools) similarly to auto_tac, but is
  5611 aimed to solve the given subgoal completely.
  5612 
  5613 
  5614 *** General ***
  5615 
  5616 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  5617 and `goalw': the theory is no longer needed as an explicit argument -
  5618 the current theory context is used; assumptions are no longer returned
  5619 at the ML-level unless one of them starts with ==> or !!; it is
  5620 recommended to convert to these new commands using isatool fixgoal
  5621 (backup your sources first!);
  5622 
  5623 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  5624 the current theory context, and 'theory' to lookup stored theories;
  5625 
  5626 * new theory section 'locale' for declaring constants, assumptions and
  5627 definitions that have local scope;
  5628 
  5629 * new theory section 'nonterminals' for purely syntactic types;
  5630 
  5631 * new theory section 'setup' for generic ML setup functions
  5632 (e.g. package initialization);
  5633 
  5634 * the distribution now includes Isabelle icons: see
  5635 lib/logo/isabelle-{small,tiny}.xpm;
  5636 
  5637 * isatool install - install binaries with absolute references to
  5638 ISABELLE_HOME/bin;
  5639 
  5640 * isatool logo -- create instances of the Isabelle logo (as EPS);
  5641 
  5642 * print mode 'emacs' reserved for Isamode;
  5643 
  5644 * support multiple print (ast) translations per constant name;
  5645 
  5646 * theorems involving oracles are now printed with a suffixed [!];
  5647 
  5648 
  5649 *** HOL ***
  5650 
  5651 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  5652 
  5653 * HOL/inductive package reorganized and improved: now supports mutual
  5654 definitions such as
  5655 
  5656   inductive EVEN ODD
  5657     intrs
  5658       null "0 : EVEN"
  5659       oddI "n : EVEN ==> Suc n : ODD"
  5660       evenI "n : ODD ==> Suc n : EVEN"
  5661 
  5662 new theorem list "elims" contains an elimination rule for each of the
  5663 recursive sets; inductive definitions now handle disjunctive premises
  5664 correctly (also ZF);
  5665 
  5666 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  5667 "mutual_induct" no longer exists - the induction rule is always
  5668 contained in "induct";
  5669 
  5670 
  5671 * HOL/datatype package re-implemented and greatly improved: now
  5672 supports mutually recursive datatypes such as
  5673 
  5674   datatype
  5675     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5676             | SUM ('a aexp) ('a aexp)
  5677             | DIFF ('a aexp) ('a aexp)
  5678             | NUM 'a
  5679   and
  5680     'a bexp = LESS ('a aexp) ('a aexp)
  5681             | AND ('a bexp) ('a bexp)
  5682             | OR ('a bexp) ('a bexp)
  5683 
  5684 as well as indirectly recursive datatypes such as
  5685 
  5686   datatype
  5687     ('a, 'b) term = Var 'a
  5688                   | App 'b ((('a, 'b) term) list)
  5689 
  5690 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5691 induction on mutually / indirectly recursive datatypes.
  5692 
  5693 Primrec equations are now stored in theory and can be accessed via
  5694 <function_name>.simps.
  5695 
  5696 INCOMPATIBILITIES:
  5697 
  5698   - Theories using datatypes must now have theory Datatype as an
  5699     ancestor.
  5700   - The specific <typename>.induct_tac no longer exists - use the
  5701     generic induct_tac instead.
  5702   - natE has been renamed to nat.exhaust - use exhaust_tac
  5703     instead of res_inst_tac ... natE. Note that the variable
  5704     names in nat.exhaust differ from the names in natE, this
  5705     may cause some "fragile" proofs to fail.
  5706   - The theorems split_<typename>_case and split_<typename>_case_asm
  5707     have been renamed to <typename>.split and <typename>.split_asm.
  5708   - Since default sorts of type variables are now handled correctly,
  5709     some datatype definitions may have to be annotated with explicit
  5710     sort constraints.
  5711   - Primrec definitions no longer require function name and type
  5712     of recursive argument.
  5713 
  5714 Consider using isatool fixdatatype to adapt your theories and proof
  5715 scripts to the new package (backup your sources first!).
  5716 
  5717 
  5718 * HOL/record package: considerably improved implementation; now
  5719 includes concrete syntax for record types, terms, updates; theorems
  5720 for surjective pairing and splitting !!-bound record variables; proof
  5721 support is as follows:
  5722 
  5723   1) standard conversions (selectors or updates applied to record
  5724 constructor terms) are part of the standard simpset;
  5725 
  5726   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5727 made part of standard simpset and claset via addIffs;
  5728 
  5729   3) a tactic for record field splitting (record_split_tac) is part of
  5730 the standard claset (addSWrapper);
  5731 
  5732 To get a better idea about these rules you may retrieve them via
  5733 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5734 the name of your record type.
  5735 
  5736 The split tactic 3) conceptually simplifies by the following rule:
  5737 
  5738   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5739 
  5740 Thus any record variable that is bound by meta-all will automatically
  5741 blow up into some record constructor term, consequently the
  5742 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5743 solve record problems automatically.
  5744 
  5745 
  5746 * reorganized the main HOL image: HOL/Integ and String loaded by
  5747 default; theory Main includes everything;
  5748 
  5749 * automatic simplification of integer sums and comparisons, using cancellation;
  5750 
  5751 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5752 
  5753 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5754 
  5755 * many new identities for unions, intersections, set difference, etc.;
  5756 
  5757 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5758 called split_if, split_split, split_sum_case and split_nat_case (to go
  5759 with add/delsplits);
  5760 
  5761 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5762 (?x::unit) = (); this is made part of the default simpset, which COULD
  5763 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5764 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5765 unit_abs_eta_conv is added in order to counter the effect of
  5766 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5767 %u.f();
  5768 
  5769 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5770 makes more sense);
  5771 
  5772 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5773   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5774   disjointness reasoning but breaking a few old proofs.
  5775 
  5776 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5777 to 'converse' from 'inverse' (for compatibility with ZF and some
  5778 literature);
  5779 
  5780 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5781 the well-founded relation;
  5782 
  5783 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5784     Compl A.  The "Compl" syntax remains available as input syntax for this
  5785     release ONLY.
  5786 
  5787 * HOL/Update: new theory of function updates:
  5788     f(a:=b) == %x. if x=a then b else f x
  5789 may also be iterated as in f(a:=b,c:=d,...);
  5790 
  5791 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5792 
  5793 * HOL/List:
  5794   - new function list_update written xs[i:=v] that updates the i-th
  5795     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5796   - new function `upt' written [i..j(] which generates the list
  5797     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5798     bound write [i..j], which is a shorthand for [i..j+1(].
  5799   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5800 
  5801 * HOL/Arith:
  5802   - removed 'pred' (predecessor) function;
  5803   - generalized some theorems about n-1;
  5804   - many new laws about "div" and "mod";
  5805   - new laws about greatest common divisors (see theory ex/Primes);
  5806 
  5807 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5808 instead of "inverse";
  5809 
  5810 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5811   of the multiset ordering;
  5812 
  5813 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5814   (not included by default);
  5815 
  5816 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5817 
  5818 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5819   programs, i.e. different program variables may have different types.
  5820 
  5821 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5822   [previously, this check worked only if the rewrite rule was unconditional]
  5823   Now rew can involve either definitions or equalities (either == or =).
  5824 
  5825 
  5826 *** ZF ***
  5827 
  5828 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5829   only the theorems proved on ZF.ML;
  5830 
  5831 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5832   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5833   disjointness reasoning but breaking a few old proofs.
  5834 
  5835 * ZF/Update: new theory of function updates
  5836     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5837   may also be iterated as in f(a:=b,c:=d,...);
  5838 
  5839 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5840 
  5841 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5842   [previously, this check worked only if the rewrite rule was unconditional]
  5843   Now rew can involve either definitions or equalities (either == or =).
  5844 
  5845 * case_tac provided for compatibility with HOL
  5846     (like the old excluded_middle_tac, but with subgoals swapped)
  5847 
  5848 
  5849 *** Internal programming interfaces ***
  5850 
  5851 * Pure: several new basic modules made available for general use, see
  5852 also src/Pure/README;
  5853 
  5854 * improved the theory data mechanism to support encapsulation (data
  5855 kind name replaced by private Object.kind, acting as authorization
  5856 key); new type-safe user interface via functor TheoryDataFun; generic
  5857 print_data function becomes basically useless;
  5858 
  5859 * removed global_names compatibility flag -- all theory declarations
  5860 are qualified by default;
  5861 
  5862 * module Pure/Syntax now offers quote / antiquote translation
  5863 functions (useful for Hoare logic etc. with implicit dependencies);
  5864 see HOL/ex/Antiquote for an example use;
  5865 
  5866 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5867 cterm -> thm;
  5868 
  5869 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5870 subgoal;
  5871 
  5872 * Display.print_goals function moved to Locale.print_goals;
  5873 
  5874 * standard print function for goals supports current_goals_markers
  5875 variable for marking begin of proof, end of proof, start of goal; the
  5876 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5877 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5878 for example;
  5879 
  5880 
  5881 
  5882 New in Isabelle98 (January 1998)
  5883 --------------------------------
  5884 
  5885 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5886 
  5887 * changed lexical syntax of terms / types: dots made part of long
  5888 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5889 
  5890 * simpset (and claset) reference variable replaced by functions
  5891 simpset / simpset_ref;
  5892 
  5893 * no longer supports theory aliases (via merge) and non-trivial
  5894 implicit merge of thms' signatures;
  5895 
  5896 * most internal names of constants changed due to qualified names;
  5897 
  5898 * changed Pure/Sequence interface (see Pure/seq.ML);
  5899 
  5900 
  5901 *** General Changes ***
  5902 
  5903 * hierachically structured name spaces (for consts, types, axms, thms
  5904 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5905 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5906 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5907 long_names for fully qualified output names; NOTE: ML programs
  5908 (special tactics, packages etc.) referring to internal names may have
  5909 to be adapted to cope with fully qualified names; in case of severe
  5910 backward campatibility problems try setting 'global_names' at compile
  5911 time to have enrything declared within a flat name space; one may also
  5912 fine tune name declarations in theories via the 'global' and 'local'
  5913 section;
  5914 
  5915 * reimplemented the implicit simpset and claset using the new anytype
  5916 data filed in signatures; references simpset:simpset ref etc. are
  5917 replaced by functions simpset:unit->simpset and
  5918 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5919 to patch your ML files accordingly;
  5920 
  5921 * HTML output now includes theory graph data for display with Java
  5922 applet or isatool browser; data generated automatically via isatool
  5923 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5924 
  5925 * defs may now be conditional; improved rewrite_goals_tac to handle
  5926 conditional equations;
  5927 
  5928 * defs now admits additional type arguments, using TYPE('a) syntax;
  5929 
  5930 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5931 creates a new theory node; implicit merge of thms' signatures is
  5932 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5933 transfer:theory->thm->thm in (rare) cases;
  5934 
  5935 * improved handling of draft signatures / theories; draft thms (and
  5936 ctyps, cterms) are automatically promoted to real ones;
  5937 
  5938 * slightly changed interfaces for oracles: admit many per theory, named
  5939 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5940 
  5941 * print_goals: optional output of const types (set show_consts and
  5942 show_types);
  5943 
  5944 * improved output of warnings (###) and errors (***);
  5945 
  5946 * subgoal_tac displays a warning if the new subgoal has type variables;
  5947 
  5948 * removed old README and Makefiles;
  5949 
  5950 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5951 
  5952 * removed obsolete init_pps and init_database;
  5953 
  5954 * deleted the obsolete tactical STATE, which was declared by
  5955     fun STATE tacfun st = tacfun st st;
  5956 
  5957 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5958 (which abbreviates $HOME);
  5959 
  5960 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5961 use isatool fixseq to adapt your ML programs (this works for fully
  5962 qualified references to the Sequence structure only!);
  5963 
  5964 * use_thy no longer requires writable current directory; it always
  5965 reloads .ML *and* .thy file, if either one is out of date;
  5966 
  5967 
  5968 *** Classical Reasoner ***
  5969 
  5970 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5971 tactics that use classical reasoning to simplify a subgoal without
  5972 splitting it into several subgoals;
  5973 
  5974 * Safe_tac: like safe_tac but uses the default claset;
  5975 
  5976 
  5977 *** Simplifier ***
  5978 
  5979 * added simplification meta rules:
  5980     (asm_)(full_)simplify: simpset -> thm -> thm;
  5981 
  5982 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5983 logics (again);
  5984 
  5985 * added prems argument to simplification procedures;
  5986 
  5987 * HOL, FOL, ZF: added infix function `addsplits':
  5988   instead of `<simpset> setloop (split_tac <thms>)'
  5989   you can simply write `<simpset> addsplits <thms>'
  5990 
  5991 
  5992 *** Syntax ***
  5993 
  5994 * TYPE('a) syntax for type reflection terms;
  5995 
  5996 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5997 
  5998 * pretty printer: changed order of mixfix annotation preference (again!);
  5999 
  6000 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  6001 
  6002 
  6003 *** HOL ***
  6004 
  6005 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6006   with `addloop' of the simplifier to faciliate case splitting in premises.
  6007 
  6008 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  6009 
  6010 * HOL/Auth: new protocol proofs including some for the Internet
  6011   protocol TLS;
  6012 
  6013 * HOL/Map: new theory of `maps' a la VDM;
  6014 
  6015 * HOL/simplifier: simplification procedures nat_cancel_sums for
  6016 cancelling out common nat summands from =, <, <= (in)equalities, or
  6017 differences; simplification procedures nat_cancel_factor for
  6018 cancelling common factor from =, <, <= (in)equalities over natural
  6019 sums; nat_cancel contains both kinds of procedures, it is installed by
  6020 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  6021 
  6022 * HOL/simplifier: terms of the form
  6023   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  6024   are rewritten to
  6025   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  6026   and those of the form
  6027   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  6028   are rewritten to
  6029   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  6030 
  6031 * HOL/datatype
  6032   Each datatype `t' now comes with a theorem `split_t_case' of the form
  6033 
  6034   P(t_case f1 ... fn x) =
  6035      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  6036         ...
  6037        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  6038      )
  6039 
  6040   and a theorem `split_t_case_asm' of the form
  6041 
  6042   P(t_case f1 ... fn x) =
  6043     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  6044         ...
  6045        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  6046      )
  6047   which can be added to a simpset via `addsplits'. The existing theorems
  6048   expand_list_case and expand_option_case have been renamed to
  6049   split_list_case and split_option_case.
  6050 
  6051 * HOL/Arithmetic:
  6052   - `pred n' is automatically converted to `n-1'.
  6053     Users are strongly encouraged not to use `pred' any longer,
  6054     because it will disappear altogether at some point.
  6055   - Users are strongly encouraged to write "0 < n" rather than
  6056     "n ~= 0". Theorems and proof tools have been modified towards this
  6057     `standard'.
  6058 
  6059 * HOL/Lists:
  6060   the function "set_of_list" has been renamed "set" (and its theorems too);
  6061   the function "nth" now takes its arguments in the reverse order and
  6062   has acquired the infix notation "!" as in "xs!n".
  6063 
  6064 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  6065 
  6066 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  6067   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  6068 
  6069 * HOL/record: extensible records with schematic structural subtyping
  6070 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  6071 still lacks various theorems and concrete record syntax;
  6072 
  6073 
  6074 *** HOLCF ***
  6075 
  6076 * removed "axioms" and "generated by" sections;
  6077 
  6078 * replaced "ops" section by extended "consts" section, which is capable of
  6079   handling the continuous function space "->" directly;
  6080 
  6081 * domain package:
  6082   . proves theorems immediately and stores them in the theory,
  6083   . creates hierachical name space,
  6084   . now uses normal mixfix annotations (instead of cinfix...),
  6085   . minor changes to some names and values (for consistency),
  6086   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  6087   . separator between mutual domain defs: changed "," to "and",
  6088   . improved handling of sort constraints;  now they have to
  6089     appear on the left-hand side of the equations only;
  6090 
  6091 * fixed LAM <x,y,zs>.b syntax;
  6092 
  6093 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  6094 adm (%x. P (t x)), where P is chainfinite and t continuous;
  6095 
  6096 
  6097 *** FOL and ZF ***
  6098 
  6099 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  6100   with `addloop' of the simplifier to faciliate case splitting in premises.
  6101 
  6102 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  6103 in HOL, they strip ALL and --> from proved theorems;
  6104 
  6105 
  6106 
  6107 New in Isabelle94-8 (May 1997)
  6108 ------------------------------
  6109 
  6110 *** General Changes ***
  6111 
  6112 * new utilities to build / run / maintain Isabelle etc. (in parts
  6113 still somewhat experimental); old Makefiles etc. still functional;
  6114 
  6115 * new 'Isabelle System Manual';
  6116 
  6117 * INSTALL text, together with ./configure and ./build scripts;
  6118 
  6119 * reimplemented type inference for greater efficiency, better error
  6120 messages and clean internal interface;
  6121 
  6122 * prlim command for dealing with lots of subgoals (an easier way of
  6123 setting goals_limit);
  6124 
  6125 
  6126 *** Syntax ***
  6127 
  6128 * supports alternative (named) syntax tables (parser and pretty
  6129 printer); internal interface is provided by add_modesyntax(_i);
  6130 
  6131 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  6132 be used in conjunction with the Isabelle symbol font; uses the
  6133 "symbols" syntax table;
  6134 
  6135 * added token_translation interface (may translate name tokens in
  6136 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  6137 the current print_mode); IMPORTANT: user print translation functions
  6138 are responsible for marking newly introduced bounds
  6139 (Syntax.mark_boundT);
  6140 
  6141 * token translations for modes "xterm" and "xterm_color" that display
  6142 names in bold, underline etc. or colors (which requires a color
  6143 version of xterm);
  6144 
  6145 * infixes may now be declared with names independent of their syntax;
  6146 
  6147 * added typed_print_translation (like print_translation, but may
  6148 access type of constant);
  6149 
  6150 
  6151 *** Classical Reasoner ***
  6152 
  6153 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  6154 some limitations.  Blast_tac...
  6155   + ignores addss, addbefore, addafter; this restriction is intrinsic
  6156   + ignores elimination rules that don't have the correct format
  6157         (the conclusion MUST be a formula variable)
  6158   + ignores types, which can make HOL proofs fail
  6159   + rules must not require higher-order unification, e.g. apply_type in ZF
  6160     [message "Function Var's argument not a bound variable" relates to this]
  6161   + its proof strategy is more general but can actually be slower
  6162 
  6163 * substitution with equality assumptions no longer permutes other
  6164 assumptions;
  6165 
  6166 * minor changes in semantics of addafter (now called addaltern); renamed
  6167 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  6168 (and access functions for it);
  6169 
  6170 * improved combination of classical reasoner and simplifier:
  6171   + functions for handling clasimpsets
  6172   + improvement of addss: now the simplifier is called _after_ the
  6173     safe steps.
  6174   + safe variant of addss called addSss: uses safe simplifications
  6175     _during_ the safe steps. It is more complete as it allows multiple
  6176     instantiations of unknowns (e.g. with slow_tac).
  6177 
  6178 *** Simplifier ***
  6179 
  6180 * added interface for simplification procedures (functions that
  6181 produce *proven* rewrite rules on the fly, depending on current
  6182 redex);
  6183 
  6184 * ordering on terms as parameter (used for ordered rewriting);
  6185 
  6186 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  6187 
  6188 * the solver is now split into a safe and an unsafe part.
  6189 This should be invisible for the normal user, except that the
  6190 functions setsolver and addsolver have been renamed to setSolver and
  6191 addSolver; added safe_asm_full_simp_tac;
  6192 
  6193 
  6194 *** HOL ***
  6195 
  6196 * a generic induction tactic `induct_tac' which works for all datatypes and
  6197 also for type `nat';
  6198 
  6199 * a generic case distinction tactic `exhaust_tac' which works for all
  6200 datatypes and also for type `nat';
  6201 
  6202 * each datatype comes with a function `size';
  6203 
  6204 * patterns in case expressions allow tuple patterns as arguments to
  6205 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  6206 
  6207 * primrec now also works with type nat;
  6208 
  6209 * recdef: a new declaration form, allows general recursive functions to be
  6210 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  6211 
  6212 * the constant for negation has been renamed from "not" to "Not" to
  6213 harmonize with FOL, ZF, LK, etc.;
  6214 
  6215 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  6216 infinite lists;
  6217 
  6218 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  6219 
  6220 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  6221 problems in commutative rings, using axiomatic type classes for + and *;
  6222 
  6223 * more examples in HOL/MiniML and HOL/Auth;
  6224 
  6225 * more default rewrite rules for quantifiers, union/intersection;
  6226 
  6227 * a new constant `arbitrary == @x.False';
  6228 
  6229 * HOLCF/IOA replaces old HOL/IOA;
  6230 
  6231 * HOLCF changes: derived all rules and arities
  6232   + axiomatic type classes instead of classes
  6233   + typedef instead of faking type definitions
  6234   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  6235   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  6236   + eliminated the types void, one, tr
  6237   + use unit lift and bool lift (with translations) instead of one and tr
  6238   + eliminated blift from Lift3.thy (use Def instead of blift)
  6239   all eliminated rules are derived as theorems --> no visible changes ;
  6240 
  6241 
  6242 *** ZF ***
  6243 
  6244 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  6245 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  6246 as ZF_cs addSIs [equalityI];
  6247 
  6248 
  6249 
  6250 New in Isabelle94-7 (November 96)
  6251 ---------------------------------
  6252 
  6253 * allowing negative levels (as offsets) in prlev and choplev;
  6254 
  6255 * super-linear speedup for large simplifications;
  6256 
  6257 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  6258 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  6259 FAIL); can suppress it using the command Delsimps (ex_simps @
  6260 all_simps); De Morgan laws are also now included, by default;
  6261 
  6262 * improved printing of ==>  :  ~:
  6263 
  6264 * new object-logic "Sequents" adds linear logic, while replacing LK
  6265 and Modal (thanks to Sara Kalvala);
  6266 
  6267 * HOL/Auth: correctness proofs for authentication protocols;
  6268 
  6269 * HOL: new auto_tac combines rewriting and classical reasoning (many
  6270 examples on HOL/Auth);
  6271 
  6272 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  6273 the rewriter and classical reasoner simultaneously;
  6274 
  6275 * function uresult no longer returns theorems in "standard" format;
  6276 regain previous version by: val uresult = standard o uresult;
  6277 
  6278 
  6279 
  6280 New in Isabelle94-6
  6281 -------------------
  6282 
  6283 * oracles -- these establish an interface between Isabelle and trusted
  6284 external reasoners, which may deliver results as theorems;
  6285 
  6286 * proof objects (in particular record all uses of oracles);
  6287 
  6288 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  6289 
  6290 * "constdefs" section in theory files;
  6291 
  6292 * "primrec" section (HOL) no longer requires names;
  6293 
  6294 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  6295 
  6296 
  6297 
  6298 New in Isabelle94-5
  6299 -------------------
  6300 
  6301 * reduced space requirements;
  6302 
  6303 * automatic HTML generation from theories;
  6304 
  6305 * theory files no longer require "..." (quotes) around most types;
  6306 
  6307 * new examples, including two proofs of the Church-Rosser theorem;
  6308 
  6309 * non-curried (1994) version of HOL is no longer distributed;
  6310 
  6311 
  6312 
  6313 New in Isabelle94-4
  6314 -------------------
  6315 
  6316 * greatly reduced space requirements;
  6317 
  6318 * theory files (.thy) no longer require \...\ escapes at line breaks;
  6319 
  6320 * searchable theorem database (see the section "Retrieving theorems" on
  6321 page 8 of the Reference Manual);
  6322 
  6323 * new examples, including Grabczewski's monumental case study of the
  6324 Axiom of Choice;
  6325 
  6326 * The previous version of HOL renamed to Old_HOL;
  6327 
  6328 * The new version of HOL (previously called CHOL) uses a curried syntax
  6329 for functions.  Application looks like f a b instead of f(a,b);
  6330 
  6331 * Mutually recursive inductive definitions finally work in HOL;
  6332 
  6333 * In ZF, pattern-matching on tuples is now available in all abstractions and
  6334 translates to the operator "split";
  6335 
  6336 
  6337 
  6338 New in Isabelle94-3
  6339 -------------------
  6340 
  6341 * new infix operator, addss, allowing the classical reasoner to
  6342 perform simplification at each step of its search.  Example:
  6343         fast_tac (cs addss ss)
  6344 
  6345 * a new logic, CHOL, the same as HOL, but with a curried syntax
  6346 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  6347 look like (a,b) instead of <a,b>;
  6348 
  6349 * PLEASE NOTE: CHOL will eventually replace HOL!
  6350 
  6351 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  6352 It translates to the operator "split".  A new theory of integers is available;
  6353 
  6354 * In ZF, integer numerals now denote two's-complement binary integers.
  6355 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  6356 
  6357 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  6358 of the Axiom of Choice;
  6359 
  6360 
  6361 
  6362 New in Isabelle94-2
  6363 -------------------
  6364 
  6365 * Significantly faster resolution;
  6366 
  6367 * the different sections in a .thy file can now be mixed and repeated
  6368 freely;
  6369 
  6370 * Database of theorems for FOL, HOL and ZF.  New
  6371 commands including qed, qed_goal and bind_thm store theorems in the database.
  6372 
  6373 * Simple database queries: return a named theorem (get_thm) or all theorems of
  6374 a given theory (thms_of), or find out what theory a theorem was proved in
  6375 (theory_of_thm);
  6376 
  6377 * Bugs fixed in the inductive definition and datatype packages;
  6378 
  6379 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  6380 and HOL_dup_cs obsolete;
  6381 
  6382 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  6383 have been removed;
  6384 
  6385 * Simpler definition of function space in ZF;
  6386 
  6387 * new results about cardinal and ordinal arithmetic in ZF;
  6388 
  6389 * 'subtype' facility in HOL for introducing new types as subsets of existing
  6390 types;
  6391 
  6392 :mode=text:wrap=hard:maxLineLen=72: