NEWS
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Wed, 03 Sep 2008 20:32:33 +0000
changeset 28119 bdf7d5f4d5b0
parent 28114 2637fb838f74
child 28143 e5c6c4aac52c
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     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Generalized Isar history, with support for linear undo, direct state
    10 addressing etc.
    11 
    12 * Recovered hiding of consts, which was accidentally broken in
    13 Isabelle2007.  Potential INCOMPATIBILITY, ``hide const c'' really
    14 makes c inaccessible; consider using ``hide (open) const c'' instead.
    15 
    16 * Removed exotic 'token_translation' command.  INCOMPATIBILITY, use ML
    17 interface instead.
    18 
    19 
    20 *** Pure ***
    21 
    22 * Global versions of theorems stemming from classes do not carry
    23 a parameter prefix any longer.  INCOMPATIBILITY.
    24 
    25 * Dropped "locale (open)".  INCOMPATBILITY.
    26 
    27 * Interpretation commands no longer attempt to simplify goal.
    28 INCOMPATIBILITY: in rare situations the generated goal differs.  Use
    29 methods intro_locales and unfold_locales to clarify.
    30 
    31 * Interpretation commands no longer accept interpretation attributes.
    32 INCOMPATBILITY.
    33 
    34 * Command 'instance': attached definitions no longer accepted.
    35 INCOMPATIBILITY, use proper 'instantiation' target.
    36 
    37 * Keyword 'code_exception' now named 'code_abort'.  INCOMPATIBILITY.
    38 
    39 * The 'axiomatization' command now only works within a global theory
    40 context.  INCOMPATIBILITY.
    41 
    42 
    43 *** Document preparation ***
    44 
    45 * Antiquotation @{lemma} now imitates a regular terminal proof,
    46 demanding keyword 'by' and supporting the full method expression
    47 syntax just like the Isar command 'by'.
    48 
    49 
    50 *** HOL ***
    51 
    52 * HOL/Orderings: class "wellorder" moved here, with explicit induction
    53 rule "less_induct" as assumption.  For instantiation of "wellorder" by
    54 means of predicate "wf", use rule wf_wellorderI.  INCOMPATIBILITY.
    55 
    56 * HOL/Orderings: added class "preorder" as superclass of "order".
    57 INCOMPATIBILITY: Instantiation proofs for order, linorder
    58 etc. slightly changed.  Some theorems named order_class.* now named
    59 preorder_class.*.
    60 
    61 * HOL/Ring_and_Field and HOL/Divides: Definition of "op dvd" has been
    62 moved to separate class dvd in Ring_and_Field; a couple of lemmas on
    63 dvd has been generalized to class comm_semiring_1.  Likewise a bunch
    64 of lemmas from Divides has been generalized from nat to class
    65 semiring_div.  INCOMPATIBILITY.  This involves the following theorem
    66 renames resulting from duplicate elimination:
    67 
    68     dvd_def_mod ~>          dvd_eq_mod_eq_0
    69     zero_dvd_iff ~>         dvd_0_left_iff
    70     DIVISION_BY_ZERO_DIV ~> div_by_0
    71     DIVISION_BY_ZERO_MOD ~> mod_by_0
    72     mult_div ~>             div_mult_self2_is_id
    73     mult_mod ~>             mod_mult_self2_is_0
    74 
    75 * HOL/Library/GCD: Curried operations gcd, lcm (for nat) and zgcd,
    76 zlcm (for int); carried together from various gcd/lcm developements in
    77 the HOL Distribution.  zgcd and zlcm replace former igcd and ilcm;
    78 corresponding theorems renamed accordingly.  INCOMPATIBILY.  To
    79 recover tupled syntax, use syntax declarations like:
    80 
    81     hide (open) const gcd
    82     abbreviation gcd where
    83       "gcd == (%(a, b). GCD.gcd a b)"
    84     notation (output)
    85       GCD.gcd ("gcd '(_, _')")
    86 
    87 (analogously for lcm, zgcd, zlcm).
    88 
    89 * HOL/Real/Rational: 'Fract k 0' now equals '0'.  INCOMPATIBILITY.
    90 
    91 * New ML antiquotation @{code}: takes constant as argument, generates
    92 corresponding code in background and inserts name of the corresponding
    93 resulting ML value/function/datatype constructor binding in place.
    94 All occurrences of @{code} with a single ML block are generated
    95 simultaneously.  Provides a generic and safe interface for
    96 instrumentalizing code generation.  See HOL/ex/Code_Antiq for a toy
    97 example, or HOL/Complex/ex/ReflectedFerrack for a more ambitious
    98 application.  In future you ought refrain from ad-hoc compiling
    99 generated SML code on the ML toplevel.  Note that (for technical
   100 reasons) @{code} cannot refer to constants for which user-defined
   101 serializations are set.  Refer to the corresponding ML counterpart
   102 directly in that cases.
   103 
   104 * Integrated image HOL-Complex with HOL.  Entry points Main.thy and
   105 Complex_Main.thy remain as they are.
   106 
   107 * New image HOL-Plain provides a minimal HOL with the most important
   108 tools available (inductive, datatype, primrec, ...).  By convention
   109 the corresponding theory Plain should be ancestor of every further
   110 (library) theory.  Some library theories now have ancestor Plain
   111 (instead of Main), thus theory Main occasionally has to be imported
   112 explicitly.
   113 
   114 * Methods "case_tac" and "induct_tac" now refer to the very same rules
   115 as the structured Isar versions "cases" and "induct", cf. the
   116 corresponding "cases" and "induct" attributes.  Mutual induction rules
   117 are now presented as a list of individual projections
   118 (e.g. foo_bar.inducts for types foo and bar); the old format with
   119 explicit HOL conjunction is no longer supported.  INCOMPATIBILITY, in
   120 rare situations a different rule is selected --- notably nested tuple
   121 elimination instead of former prod.exhaust: use explicit (case_tac t
   122 rule: prod.exhaust) here.
   123 
   124 * Attributes "cases", "induct", "coinduct" support "del" option.
   125 
   126 * Removed fact "case_split_thm", which duplicates "case_split".
   127 
   128 * Command 'rep_datatype': instead of theorem names the command now
   129 takes a list of terms denoting the constructors of the type to be
   130 represented as datatype.  The characteristic theorems have to be
   131 proven.  INCOMPATIBILITY.  Also observe that the following theorems
   132 have disappeared in favour of existing ones:
   133 
   134     unit_induct                 ~> unit.induct
   135     prod_induct                 ~> prod.induct
   136     sum_induct                  ~> sum.induct
   137     Suc_Suc_eq                  ~> nat.inject
   138     Suc_not_Zero Zero_not_Suc   ~> nat.distinct
   139 
   140 * Library/Nat_Infinity: added addition, numeral syntax and more
   141 instantiations for algebraic structures.  Removed some duplicate
   142 theorems.  Changes in simp rules.  INCOMPATIBILITY.
   143 
   144 * ATP selection (E/Vampire/Spass) is now via Proof General's settings
   145 menu.
   146 
   147 
   148 *** HOL-Algebra ***
   149 
   150 * New locales for orders and lattices where the equivalence relation
   151   is not restricted to equality.  INCOMPATIBILITY: all order and
   152   lattice locales use a record structure with field eq for the
   153   equivalence.
   154 
   155 * New theory of factorial domains.
   156 
   157 * Units_l_inv and Units_r_inv are now simprules by default.
   158 INCOMPATIBILITY.  Simplifier proof that require deletion of l_inv
   159 and/or r_inv will now also require deletion of these lemmas.
   160 
   161 * Renamed the following theorems.  INCOMPATIBILITY.
   162 UpperD ~> Upper_memD
   163 LowerD ~> Lower_memD
   164 least_carrier ~> least_closed
   165 greatest_carrier ~> greatest_closed
   166 greatest_Lower_above ~> greatest_Lower_below
   167 one_zero ~> carrier_one_zero
   168 one_not_zero ~> carrier_one_not_zero  (collision with assumption)
   169 
   170 
   171 *** HOL-NSA ***
   172 
   173 * Created new image HOL-NSA, containing theories of nonstandard
   174 analysis which were previously part of HOL-Complex.  Entry point
   175 Hyperreal.thy remains valid, but theories formerly using
   176 Complex_Main.thy should now use new entry point Hypercomplex.thy.
   177 
   178 
   179 *** ZF ***
   180 
   181 * Proof of Zorn's Lemma for partial orders.
   182 
   183 
   184 *** ML ***
   185 
   186 * Generic Toplevel.add_hook interface allows to analyze the result of
   187 transactions.  E.g. see src/Pure/ProofGeneral/proof_general_pgip.ML
   188 for theorem dependency output of transactions resulting in a new
   189 theory state.
   190 
   191 * Name bindings in higher specification mechanisms (notably
   192 LocalTheory.define, LocalTheory.note, and derived packages) are now
   193 formalized as type Name.binding, replacing old bstring.
   194 INCOMPATIBILITY, need to wrap strings via Name.binding function, see
   195 also Name.name_of.  Packages should pass name bindings given by the
   196 user to underlying specification mechanisms; this enables precise
   197 tracking of source positions, for example.
   198 
   199 * Result facts (from PureThy.note_thms, ProofContext.note_thms,
   200 LocalTheory.note etc.) now refer to the *full* internal name, not the
   201 bstring as before.  INCOMPATIBILITY, not detected by ML type-checking!
   202 
   203 * Rules and tactics that read instantiations (read_instantiate,
   204 res_inst_tac, thin_tac, subgoal_tac etc.) now demand a proper proof
   205 context, which is required for parsing and type-checking.  Moreover,
   206 the variables are specified as plain indexnames, not string encodings
   207 thereof.  INCOMPATIBILITY.
   208 
   209 * Disposed old type and term read functions (Sign.read_def_typ,
   210 Sign.read_typ, Sign.read_def_terms, Sign.read_term,
   211 Thm.read_def_cterms, Thm.read_cterm etc.).  INCOMPATIBILITY, should
   212 use regular Syntax.read_typ, Syntax.read_term, Syntax.read_typ_global,
   213 Syntax.read_term_global etc.; see also OldGoals.read_term as last
   214 resort for legacy applications.
   215 
   216 * Antiquotations: block-structured compilation context indicated by
   217 \<lbrace> ... \<rbrace>; additional antiquotation forms:
   218 
   219   @{let ?pat = term}                      - term abbreviation (HO matching)
   220   @{note name = fact}                     - fact abbreviation
   221   @{thm fact}                             - singleton fact (with attributes)
   222   @{thms fact}                            - general fact (with attributes)
   223   @{lemma prop by method}                 - singleton goal
   224   @{lemma prop by meth1 meth2}            - singleton goal
   225   @{lemma prop1 ... propN by method}      - general goal
   226   @{lemma prop1 ... propN by meth1 meth2} - general goal
   227   @{lemma (open) ...}                     - open derivation
   228 
   229 
   230 *** System ***
   231 
   232 * Isabelle/lib/classes/Pure.jar provides basic support to integrate
   233 the Isabelle process into a JVM/Scala application.  See
   234 Isabelle/lib/jedit/plugin for a minimal example.  (The obsolete Java
   235 process wrapper has been discontinued.)
   236 
   237 * Status messages (with exact source position information) are
   238 emitted, if proper markup print mode is enabled.  This allows
   239 user-interface components to provide detailed feedback on internal
   240 prover operations.
   241 
   242 * Homegrown Isabelle font with unicode layout, see Isabelle/lib/fonts.
   243 
   244 
   245 
   246 New in Isabelle2008 (June 2008)
   247 -------------------------------
   248 
   249 *** General ***
   250 
   251 * The Isabelle/Isar Reference Manual (isar-ref) has been reorganized
   252 and updated, with formally checked references as hyperlinks.
   253 
   254 * Theory loader: use_thy (and similar operations) no longer set the
   255 implicit ML context, which was occasionally hard to predict and in
   256 conflict with concurrency.  INCOMPATIBILITY, use ML within Isar which
   257 provides a proper context already.
   258 
   259 * Theory loader: old-style ML proof scripts being *attached* to a thy
   260 file are no longer supported.  INCOMPATIBILITY, regular 'uses' and
   261 'use' within a theory file will do the job.
   262 
   263 * Name space merge now observes canonical order, i.e. the second space
   264 is inserted into the first one, while existing entries in the first
   265 space take precedence.  INCOMPATIBILITY in rare situations, may try to
   266 swap theory imports.
   267 
   268 * Syntax: symbol \<chi> is now considered a letter.  Potential
   269 INCOMPATIBILITY in identifier syntax etc.
   270 
   271 * Outer syntax: string tokens no longer admit escaped white space,
   272 which was an accidental (undocumented) feature.  INCOMPATIBILITY, use
   273 white space without escapes.
   274 
   275 * Outer syntax: string tokens may contain arbitrary character codes
   276 specified via 3 decimal digits (as in SML).  E.g. "foo\095bar" for
   277 "foo_bar".
   278 
   279 
   280 *** Pure ***
   281 
   282 * Context-dependent token translations.  Default setup reverts locally
   283 fixed variables, and adds hilite markup for undeclared frees.
   284 
   285 * Unused theorems can be found using the new command 'unused_thms'.
   286 There are three ways of invoking it:
   287 
   288 (1) unused_thms
   289      Only finds unused theorems in the current theory.
   290 
   291 (2) unused_thms thy_1 ... thy_n -
   292      Finds unused theorems in the current theory and all of its ancestors,
   293      excluding the theories thy_1 ... thy_n and all of their ancestors.
   294 
   295 (3) unused_thms thy_1 ... thy_n - thy'_1 ... thy'_m
   296      Finds unused theorems in the theories thy'_1 ... thy'_m and all of
   297      their ancestors, excluding the theories thy_1 ... thy_n and all of
   298      their ancestors.
   299 
   300 In order to increase the readability of the list produced by
   301 unused_thms, theorems that have been created by a particular instance
   302 of a theory command such as 'inductive' or 'function' are considered
   303 to belong to the same "group", meaning that if at least one theorem in
   304 this group is used, the other theorems in the same group are no longer
   305 reported as unused.  Moreover, if all theorems in the group are
   306 unused, only one theorem in the group is displayed.
   307 
   308 Note that proof objects have to be switched on in order for
   309 unused_thms to work properly (i.e. !proofs must be >= 1, which is
   310 usually the case when using Proof General with the default settings).
   311 
   312 * Authentic naming of facts disallows ad-hoc overwriting of previous
   313 theorems within the same name space.  INCOMPATIBILITY, need to remove
   314 duplicate fact bindings, or even accidental fact duplications.  Note
   315 that tools may maintain dynamically scoped facts systematically, using
   316 PureThy.add_thms_dynamic.
   317 
   318 * Command 'hide' now allows to hide from "fact" name space as well.
   319 
   320 * Eliminated destructive theorem database, simpset, claset, and
   321 clasimpset.  Potential INCOMPATIBILITY, really need to observe linear
   322 update of theories within ML code.
   323 
   324 * Eliminated theory ProtoPure and CPure, leaving just one Pure theory.
   325 INCOMPATIBILITY, object-logics depending on former Pure require
   326 additional setup PureThy.old_appl_syntax_setup; object-logics
   327 depending on former CPure need to refer to Pure.
   328 
   329 * Commands 'use' and 'ML' are now purely functional, operating on
   330 theory/local_theory.  Removed former 'ML_setup' (on theory), use 'ML'
   331 instead.  Added 'ML_val' as mere diagnostic replacement for 'ML'.
   332 INCOMPATIBILITY.
   333 
   334 * Command 'setup': discontinued implicit version with ML reference.
   335 
   336 * Instantiation target allows for simultaneous specification of class
   337 instance operations together with an instantiation proof.
   338 Type-checking phase allows to refer to class operations uniformly.
   339 See src/HOL/Complex/Complex.thy for an Isar example and
   340 src/HOL/Library/Eval.thy for an ML example.
   341 
   342 * Indexing of literal facts: be more serious about including only
   343 facts from the visible specification/proof context, but not the
   344 background context (locale etc.).  Affects `prop` notation and method
   345 "fact".  INCOMPATIBILITY: need to name facts explicitly in rare
   346 situations.
   347 
   348 * Method "cases", "induct", "coinduct": removed obsolete/undocumented
   349 "(open)" option, which used to expose internal bound variables to the
   350 proof text.
   351 
   352 * Isar statements: removed obsolete case "rule_context".
   353 INCOMPATIBILITY, better use explicit fixes/assumes.
   354 
   355 * Locale proofs: default proof step now includes 'unfold_locales';
   356 hence 'proof' without argument may be used to unfold locale
   357 predicates.
   358 
   359 
   360 *** Document preparation ***
   361 
   362 * Simplified pdfsetup.sty: color/hyperref is used unconditionally for
   363 both pdf and dvi (hyperlinks usually work in xdvi as well); removed
   364 obsolete thumbpdf setup (contemporary PDF viewers do this on the
   365 spot); renamed link color from "darkblue" to "linkcolor" (default
   366 value unchanged, can be redefined via \definecolor); no longer sets
   367 "a4paper" option (unnecessary or even intrusive).
   368 
   369 * Antiquotation @{lemma A method} proves proposition A by the given
   370 method (either a method name or a method name plus (optional) method
   371 arguments in parentheses) and prints A just like @{prop A}.
   372 
   373 
   374 *** HOL ***
   375 
   376 * New primrec package.  Specification syntax conforms in style to
   377 definition/function/....  No separate induction rule is provided.  The
   378 "primrec" command distinguishes old-style and new-style specifications
   379 by syntax.  The former primrec package is now named OldPrimrecPackage.
   380 When adjusting theories, beware: constants stemming from new-style
   381 primrec specifications have authentic syntax.
   382 
   383 * Metis prover is now an order of magnitude faster, and also works
   384 with multithreading.
   385 
   386 * Metis: the maximum number of clauses that can be produced from a
   387 theorem is now given by the attribute max_clauses.  Theorems that
   388 exceed this number are ignored, with a warning printed.
   389 
   390 * Sledgehammer no longer produces structured proofs by default. To
   391 enable, declare [[sledgehammer_full = true]].  Attributes
   392 reconstruction_modulus, reconstruction_sorts renamed
   393 sledgehammer_modulus, sledgehammer_sorts.  INCOMPATIBILITY.
   394 
   395 * Method "induct_scheme" derives user-specified induction rules
   396 from well-founded induction and completeness of patterns. This factors
   397 out some operations that are done internally by the function package
   398 and makes them available separately.  See
   399 src/HOL/ex/Induction_Scheme.thy for examples.
   400 
   401 * More flexible generation of measure functions for termination
   402 proofs: Measure functions can be declared by proving a rule of the
   403 form "is_measure f" and giving it the [measure_function] attribute.
   404 The "is_measure" predicate is logically meaningless (always true), and
   405 just guides the heuristic.  To find suitable measure functions, the
   406 termination prover sets up the goal "is_measure ?f" of the appropriate
   407 type and generates all solutions by prolog-style backwards proof using
   408 the declared rules.
   409 
   410 This setup also deals with rules like 
   411 
   412   "is_measure f ==> is_measure (list_size f)"
   413 
   414 which accommodates nested datatypes that recurse through lists.
   415 Similar rules are predeclared for products and option types.
   416 
   417 * Turned the type of sets "'a set" into an abbreviation for "'a => bool"
   418 
   419   INCOMPATIBILITIES:
   420 
   421   - Definitions of overloaded constants on sets have to be replaced by
   422     definitions on => and bool.
   423 
   424   - Some definitions of overloaded operators on sets can now be proved
   425     using the definitions of the operators on => and bool.  Therefore,
   426     the following theorems have been renamed:
   427 
   428       subset_def   -> subset_eq
   429       psubset_def  -> psubset_eq
   430       set_diff_def -> set_diff_eq
   431       Compl_def    -> Compl_eq
   432       Sup_set_def  -> Sup_set_eq
   433       Inf_set_def  -> Inf_set_eq
   434       sup_set_def  -> sup_set_eq
   435       inf_set_def  -> inf_set_eq
   436 
   437   - Due to the incompleteness of the HO unification algorithm, some
   438     rules such as subst may require manual instantiation, if some of
   439     the unknowns in the rule is a set.
   440 
   441   - Higher order unification and forward proofs:
   442     The proof pattern
   443 
   444       have "P (S::'a set)" <...>
   445       then have "EX S. P S" ..
   446 
   447     no longer works (due to the incompleteness of the HO unification
   448     algorithm) and must be replaced by the pattern
   449 
   450       have "EX S. P S"
   451       proof
   452         show "P S" <...>
   453       qed
   454 
   455   - Calculational reasoning with subst (or similar rules):
   456     The proof pattern
   457 
   458       have "P (S::'a set)" <...>
   459       also have "S = T" <...>
   460       finally have "P T" .
   461 
   462     no longer works (for similar reasons as the previous example) and
   463     must be replaced by something like
   464 
   465       have "P (S::'a set)" <...>
   466       moreover have "S = T" <...>
   467       ultimately have "P T" by simp
   468 
   469   - Tactics or packages written in ML code:
   470     Code performing pattern matching on types via
   471 
   472       Type ("set", [T]) => ...
   473 
   474     must be rewritten. Moreover, functions like strip_type or
   475     binder_types no longer return the right value when applied to a
   476     type of the form
   477 
   478       T1 => ... => Tn => U => bool
   479 
   480     rather than
   481 
   482       T1 => ... => Tn => U set
   483 
   484 * Merged theories Wellfounded_Recursion, Accessible_Part and
   485 Wellfounded_Relations to theory Wellfounded.
   486 
   487 * Explicit class "eq" for executable equality.  INCOMPATIBILITY.
   488 
   489 * Class finite no longer treats UNIV as class parameter.  Use class
   490 enum from theory Library/Enum instead to achieve a similar effect.
   491 INCOMPATIBILITY.
   492 
   493 * Theory List: rule list_induct2 now has explicitly named cases "Nil"
   494 and "Cons".  INCOMPATIBILITY.
   495 
   496 * HOL (and FOL): renamed variables in rules imp_elim and swap.
   497 Potential INCOMPATIBILITY.
   498 
   499 * Theory Product_Type: duplicated lemmas split_Pair_apply and
   500 injective_fst_snd removed, use split_eta and prod_eqI instead.
   501 Renamed upd_fst to apfst and upd_snd to apsnd.  INCOMPATIBILITY.
   502 
   503 * Theory Nat: removed redundant lemmas that merely duplicate lemmas of
   504 the same name in theory Orderings:
   505 
   506   less_trans
   507   less_linear
   508   le_imp_less_or_eq
   509   le_less_trans
   510   less_le_trans
   511   less_not_sym
   512   less_asym
   513 
   514 Renamed less_imp_le to less_imp_le_nat, and less_irrefl to
   515 less_irrefl_nat.  Potential INCOMPATIBILITY due to more general types
   516 and different variable names.
   517 
   518 * Library/Option_ord.thy: Canonical order on option type.
   519 
   520 * Library/RBT.thy: Red-black trees, an efficient implementation of
   521 finite maps.
   522 
   523 * Library/Countable.thy: Type class for countable types.
   524 
   525 * Theory Int: The representation of numerals has changed.  The infix
   526 operator BIT and the bit datatype with constructors B0 and B1 have
   527 disappeared.  INCOMPATIBILITY, use "Int.Bit0 x" and "Int.Bit1 y" in
   528 place of "x BIT bit.B0" and "y BIT bit.B1", respectively.  Theorems
   529 involving BIT, B0, or B1 have been renamed with "Bit0" or "Bit1"
   530 accordingly.
   531 
   532 * Theory Nat: definition of <= and < on natural numbers no longer
   533 depend on well-founded relations.  INCOMPATIBILITY.  Definitions
   534 le_def and less_def have disappeared.  Consider lemmas not_less
   535 [symmetric, where ?'a = nat] and less_eq [symmetric] instead.
   536 
   537 * Theory Finite_Set: locales ACf, ACe, ACIf, ACIfSL and ACIfSLlin
   538 (whose purpose mainly is for various fold_set functionals) have been
   539 abandoned in favor of the existing algebraic classes
   540 ab_semigroup_mult, comm_monoid_mult, ab_semigroup_idem_mult,
   541 lower_semilattice (resp. upper_semilattice) and linorder.
   542 INCOMPATIBILITY.
   543 
   544 * Theory Transitive_Closure: induct and cases rules now declare proper
   545 case_names ("base" and "step").  INCOMPATIBILITY.
   546 
   547 * Theorem Inductive.lfp_ordinal_induct generalized to complete
   548 lattices.  The form set-specific version is available as
   549 Inductive.lfp_ordinal_induct_set.
   550 
   551 * Renamed theorems "power.simps" to "power_int.simps".
   552 INCOMPATIBILITY.
   553 
   554 * Class semiring_div provides basic abstract properties of semirings
   555 with division and modulo operations.  Subsumes former class dvd_mod.
   556 
   557 * Merged theories IntDef, Numeral and IntArith into unified theory
   558 Int.  INCOMPATIBILITY.
   559 
   560 * Theory Library/Code_Index: type "index" now represents natural
   561 numbers rather than integers.  INCOMPATIBILITY.
   562 
   563 * New class "uminus" with operation "uminus" (split of from class
   564 "minus" which now only has operation "minus", binary).
   565 INCOMPATIBILITY.
   566 
   567 * Constants "card", "internal_split", "option_map" now with authentic
   568 syntax.  INCOMPATIBILITY.
   569 
   570 * Definitions subset_def, psubset_def, set_diff_def, Compl_def,
   571 le_bool_def, less_bool_def, le_fun_def, less_fun_def, inf_bool_def,
   572 sup_bool_def, Inf_bool_def, Sup_bool_def, inf_fun_def, sup_fun_def,
   573 Inf_fun_def, Sup_fun_def, inf_set_def, sup_set_def, Inf_set_def,
   574 Sup_set_def, le_def, less_def, option_map_def now with object
   575 equality.  INCOMPATIBILITY.
   576 
   577 * Records. Removed K_record, and replaced it by pure lambda term
   578 %x. c. The simplifier setup is now more robust against eta expansion.
   579 INCOMPATIBILITY: in cases explicitly referring to K_record.
   580 
   581 * Library/Multiset: {#a, b, c#} abbreviates {#a#} + {#b#} + {#c#}.
   582 
   583 * Library/ListVector: new theory of arithmetic vector operations.
   584 
   585 * Library/Order_Relation: new theory of various orderings as sets of
   586 pairs.  Defines preorders, partial orders, linear orders and
   587 well-orders on sets and on types.
   588 
   589 
   590 *** ZF ***
   591 
   592 * Renamed some theories to allow to loading both ZF and HOL in the
   593 same session:
   594 
   595   Datatype  -> Datatype_ZF
   596   Inductive -> Inductive_ZF
   597   Int       -> Int_ZF
   598   IntDiv    -> IntDiv_ZF
   599   Nat       -> Nat_ZF
   600   List      -> List_ZF
   601   Main      -> Main_ZF
   602 
   603 INCOMPATIBILITY: ZF theories that import individual theories below
   604 Main might need to be adapted.  Regular theory Main is still
   605 available, as trivial extension of Main_ZF.
   606 
   607 
   608 *** ML ***
   609 
   610 * ML within Isar: antiquotation @{const name} or @{const
   611 name(typargs)} produces statically-checked Const term.
   612 
   613 * Functor NamedThmsFun: data is available to the user as dynamic fact
   614 (of the same name).  Removed obsolete print command.
   615 
   616 * Removed obsolete "use_legacy_bindings" function.
   617 
   618 * The ``print mode'' is now a thread-local value derived from a global
   619 template (the former print_mode reference), thus access becomes
   620 non-critical.  The global print_mode reference is for session
   621 management only; user-code should use print_mode_value,
   622 print_mode_active, PrintMode.setmp etc.  INCOMPATIBILITY.
   623 
   624 * Functions system/system_out provide a robust way to invoke external
   625 shell commands, with propagation of interrupts (requires Poly/ML 5.2).
   626 Do not use OS.Process.system etc. from the basis library!
   627 
   628 
   629 *** System ***
   630 
   631 * Default settings: PROOFGENERAL_OPTIONS no longer impose xemacs ---
   632 in accordance with Proof General 3.7, which prefers GNU emacs.
   633 
   634 * isatool tty runs Isabelle process with plain tty interaction;
   635 optional line editor may be specified via ISABELLE_LINE_EDITOR
   636 setting, the default settings attempt to locate "ledit" and "rlwrap".
   637 
   638 * isatool browser now works with Cygwin as well, using general
   639 "javapath" function defined in Isabelle process environment.
   640 
   641 * YXML notation provides a simple and efficient alternative to
   642 standard XML transfer syntax.  See src/Pure/General/yxml.ML and
   643 isatool yxml as described in the Isabelle system manual.
   644 
   645 * JVM class isabelle.IsabelleProcess (located in Isabelle/lib/classes)
   646 provides general wrapper for managing an Isabelle process in a robust
   647 fashion, with ``cooked'' output from stdin/stderr.
   648 
   649 * Rudimentary Isabelle plugin for jEdit (see Isabelle/lib/jedit),
   650 based on Isabelle/JVM process wrapper (see Isabelle/lib/classes).
   651 
   652 * Removed obsolete THIS_IS_ISABELLE_BUILD feature.  NB: the documented
   653 way of changing the user's settings is via
   654 ISABELLE_HOME_USER/etc/settings, which is a fully featured bash
   655 script.
   656 
   657 * Multithreading.max_threads := 0 refers to the number of actual CPU
   658 cores of the underlying machine, which is a good starting point for
   659 optimal performance tuning.  The corresponding usedir option -M allows
   660 "max" as an alias for "0".  WARNING: does not work on certain versions
   661 of Mac OS (with Poly/ML 5.1).
   662 
   663 * isabelle-process: non-ML sessions are run with "nice", to reduce the
   664 adverse effect of Isabelle flooding interactive front-ends (notably
   665 ProofGeneral / XEmacs).
   666 
   667 
   668 
   669 New in Isabelle2007 (November 2007)
   670 -----------------------------------
   671 
   672 *** General ***
   673 
   674 * More uniform information about legacy features, notably a
   675 warning/error of "Legacy feature: ...", depending on the state of the
   676 tolerate_legacy_features flag (default true). FUTURE INCOMPATIBILITY:
   677 legacy features will disappear eventually.
   678 
   679 * Theory syntax: the header format ``theory A = B + C:'' has been
   680 discontinued in favour of ``theory A imports B C begin''.  Use isatool
   681 fixheaders to convert existing theory files.  INCOMPATIBILITY.
   682 
   683 * Theory syntax: the old non-Isar theory file format has been
   684 discontinued altogether.  Note that ML proof scripts may still be used
   685 with Isar theories; migration is usually quite simple with the ML
   686 function use_legacy_bindings.  INCOMPATIBILITY.
   687 
   688 * Theory syntax: some popular names (e.g. 'class', 'declaration',
   689 'fun', 'help', 'if') are now keywords.  INCOMPATIBILITY, use double
   690 quotes.
   691 
   692 * Theory loader: be more serious about observing the static theory
   693 header specifications (including optional directories), but not the
   694 accidental file locations of previously successful loads.  The strict
   695 update policy of former update_thy is now already performed by
   696 use_thy, so the former has been removed; use_thys updates several
   697 theories simultaneously, just as 'imports' within a theory header
   698 specification, but without merging the results.  Potential
   699 INCOMPATIBILITY: may need to refine theory headers and commands
   700 ROOT.ML which depend on load order.
   701 
   702 * Theory loader: optional support for content-based file
   703 identification, instead of the traditional scheme of full physical
   704 path plus date stamp; configured by the ISABELLE_FILE_IDENT setting
   705 (cf. the system manual).  The new scheme allows to work with
   706 non-finished theories in persistent session images, such that source
   707 files may be moved later on without requiring reloads.
   708 
   709 * Theory loader: old-style ML proof scripts being *attached* to a thy
   710 file (with the same base name as the theory) are considered a legacy
   711 feature, which will disappear eventually. Even now, the theory loader
   712 no longer maintains dependencies on such files.
   713 
   714 * Syntax: the scope for resolving ambiguities via type-inference is
   715 now limited to individual terms, instead of whole simultaneous
   716 specifications as before. This greatly reduces the complexity of the
   717 syntax module and improves flexibility by separating parsing and
   718 type-checking. INCOMPATIBILITY: additional type-constraints (explicit
   719 'fixes' etc.) are required in rare situations.
   720 
   721 * Syntax: constants introduced by new-style packages ('definition',
   722 'abbreviation' etc.) are passed through the syntax module in
   723 ``authentic mode''. This means that associated mixfix annotations
   724 really stick to such constants, independently of potential name space
   725 ambiguities introduced later on. INCOMPATIBILITY: constants in parse
   726 trees are represented slightly differently, may need to adapt syntax
   727 translations accordingly. Use CONST marker in 'translations' and
   728 @{const_syntax} antiquotation in 'parse_translation' etc.
   729 
   730 * Legacy goal package: reduced interface to the bare minimum required
   731 to keep existing proof scripts running.  Most other user-level
   732 functions are now part of the OldGoals structure, which is *not* open
   733 by default (consider isatool expandshort before open OldGoals).
   734 Removed top_sg, prin, printyp, pprint_term/typ altogether, because
   735 these tend to cause confusion about the actual goal (!) context being
   736 used here, which is not necessarily the same as the_context().
   737 
   738 * Command 'find_theorems': supports "*" wild-card in "name:"
   739 criterion; "with_dups" option.  Certain ProofGeneral versions might
   740 support a specific search form (see ProofGeneral/CHANGES).
   741 
   742 * The ``prems limit'' option (cf. ProofContext.prems_limit) is now -1
   743 by default, which means that "prems" (and also "fixed variables") are
   744 suppressed from proof state output.  Note that the ProofGeneral
   745 settings mechanism allows to change and save options persistently, but
   746 older versions of Isabelle will fail to start up if a negative prems
   747 limit is imposed.
   748 
   749 * Local theory targets may be specified by non-nested blocks of
   750 ``context/locale/class ... begin'' followed by ``end''.  The body may
   751 contain definitions, theorems etc., including any derived mechanism
   752 that has been implemented on top of these primitives.  This concept
   753 generalizes the existing ``theorem (in ...)'' towards more versatility
   754 and scalability.
   755 
   756 * Proof General interface: proper undo of final 'end' command;
   757 discontinued Isabelle/classic mode (ML proof scripts).
   758 
   759 
   760 *** Document preparation ***
   761 
   762 * Added antiquotation @{theory name} which prints the given name,
   763 after checking that it refers to a valid ancestor theory in the
   764 current context.
   765 
   766 * Added antiquotations @{ML_type text} and @{ML_struct text} which
   767 check the given source text as ML type/structure, printing verbatim.
   768 
   769 * Added antiquotation @{abbrev "c args"} which prints the abbreviation
   770 "c args == rhs" given in the current context.  (Any number of
   771 arguments may be given on the LHS.)
   772 
   773 
   774 *** Pure ***
   775 
   776 * The 'class' package offers a combination of axclass and locale to
   777 achieve Haskell-like type classes in Isabelle.  Definitions and
   778 theorems within a class context produce both relative results (with
   779 implicit parameters according to the locale context), and polymorphic
   780 constants with qualified polymorphism (according to the class
   781 context).  Within the body context of a 'class' target, a separate
   782 syntax layer ("user space type system") takes care of converting
   783 between global polymorphic consts and internal locale representation.
   784 See src/HOL/ex/Classpackage.thy for examples (as well as main HOL).
   785 "isatool doc classes" provides a tutorial.
   786 
   787 * Generic code generator framework allows to generate executable
   788 code for ML and Haskell (including Isabelle classes).  A short usage
   789 sketch:
   790 
   791     internal compilation:
   792         export_code <list of constants (term syntax)> in SML
   793     writing SML code to a file:
   794         export_code <list of constants (term syntax)> in SML <filename>
   795     writing OCaml code to a file:
   796         export_code <list of constants (term syntax)> in OCaml <filename>
   797     writing Haskell code to a bunch of files:
   798         export_code <list of constants (term syntax)> in Haskell <filename>
   799 
   800     evaluating closed propositions to True/False using code generation:
   801         method ``eval''
   802 
   803 Reasonable default setup of framework in HOL.
   804 
   805 Theorem attributs for selecting and transforming function equations theorems:
   806 
   807     [code fun]:        select a theorem as function equation for a specific constant
   808     [code fun del]:    deselect a theorem as function equation for a specific constant
   809     [code inline]:     select an equation theorem for unfolding (inlining) in place
   810     [code inline del]: deselect an equation theorem for unfolding (inlining) in place
   811 
   812 User-defined serializations (target in {SML, OCaml, Haskell}):
   813 
   814     code_const <and-list of constants (term syntax)>
   815       {(target) <and-list of const target syntax>}+
   816 
   817     code_type <and-list of type constructors>
   818       {(target) <and-list of type target syntax>}+
   819 
   820     code_instance <and-list of instances>
   821       {(target)}+
   822         where instance ::= <type constructor> :: <class>
   823 
   824     code_class <and_list of classes>
   825       {(target) <and-list of class target syntax>}+
   826         where class target syntax ::= <class name> {where {<classop> == <target syntax>}+}?
   827 
   828 code_instance and code_class only are effective to target Haskell.
   829 
   830 For example usage see src/HOL/ex/Codegenerator.thy and
   831 src/HOL/ex/Codegenerator_Pretty.thy.  A separate tutorial on code
   832 generation from Isabelle/HOL theories is available via "isatool doc
   833 codegen".
   834 
   835 * Code generator: consts in 'consts_code' Isar commands are now
   836 referred to by usual term syntax (including optional type
   837 annotations).
   838 
   839 * Command 'no_translations' removes translation rules from theory
   840 syntax.
   841 
   842 * Overloaded definitions are now actually checked for acyclic
   843 dependencies.  The overloading scheme is slightly more general than
   844 that of Haskell98, although Isabelle does not demand an exact
   845 correspondence to type class and instance declarations.
   846 INCOMPATIBILITY, use ``defs (unchecked overloaded)'' to admit more
   847 exotic versions of overloading -- at the discretion of the user!
   848 
   849 Polymorphic constants are represented via type arguments, i.e. the
   850 instantiation that matches an instance against the most general
   851 declaration given in the signature.  For example, with the declaration
   852 c :: 'a => 'a => 'a, an instance c :: nat => nat => nat is represented
   853 as c(nat).  Overloading is essentially simultaneous structural
   854 recursion over such type arguments.  Incomplete specification patterns
   855 impose global constraints on all occurrences, e.g. c('a * 'a) on the
   856 LHS means that more general c('a * 'b) will be disallowed on any RHS.
   857 Command 'print_theory' outputs the normalized system of recursive
   858 equations, see section "definitions".
   859 
   860 * Configuration options are maintained within the theory or proof
   861 context (with name and type bool/int/string), providing a very simple
   862 interface to a poor-man's version of general context data.  Tools may
   863 declare options in ML (e.g. using Attrib.config_int) and then refer to
   864 these values using Config.get etc.  Users may change options via an
   865 associated attribute of the same name.  This form of context
   866 declaration works particularly well with commands 'declare' or
   867 'using', for example ``declare [[foo = 42]]''.  Thus it has become
   868 very easy to avoid global references, which would not observe Isar
   869 toplevel undo/redo and fail to work with multithreading.
   870 
   871 Various global ML references of Pure and HOL have been turned into
   872 configuration options:
   873 
   874   Unify.search_bound		unify_search_bound
   875   Unify.trace_bound		unify_trace_bound
   876   Unify.trace_simp		unify_trace_simp
   877   Unify.trace_types		unify_trace_types
   878   Simplifier.simp_depth_limit	simp_depth_limit
   879   Blast.depth_limit		blast_depth_limit
   880   DatatypeProp.dtK		datatype_distinctness_limit
   881   fast_arith_neq_limit  	fast_arith_neq_limit
   882   fast_arith_split_limit	fast_arith_split_limit
   883 
   884 * Named collections of theorems may be easily installed as context
   885 data using the functor NamedThmsFun (see also
   886 src/Pure/Tools/named_thms.ML).  The user may add or delete facts via
   887 attributes; there is also a toplevel print command.  This facility is
   888 just a common case of general context data, which is the preferred way
   889 for anything more complex than just a list of facts in canonical
   890 order.
   891 
   892 * Isar: command 'declaration' augments a local theory by generic
   893 declaration functions written in ML.  This enables arbitrary content
   894 being added to the context, depending on a morphism that tells the
   895 difference of the original declaration context wrt. the application
   896 context encountered later on.
   897 
   898 * Isar: proper interfaces for simplification procedures.  Command
   899 'simproc_setup' declares named simprocs (with match patterns, and body
   900 text in ML).  Attribute "simproc" adds/deletes simprocs in the current
   901 context.  ML antiquotation @{simproc name} retrieves named simprocs.
   902 
   903 * Isar: an extra pair of brackets around attribute declarations
   904 abbreviates a theorem reference involving an internal dummy fact,
   905 which will be ignored later --- only the effect of the attribute on
   906 the background context will persist.  This form of in-place
   907 declarations is particularly useful with commands like 'declare' and
   908 'using', for example ``have A using [[simproc a]] by simp''.
   909 
   910 * Isar: method "assumption" (and implicit closing of subproofs) now
   911 takes simple non-atomic goal assumptions into account: after applying
   912 an assumption as a rule the resulting subgoals are solved by atomic
   913 assumption steps.  This is particularly useful to finish 'obtain'
   914 goals, such as "!!x. (!!x. P x ==> thesis) ==> P x ==> thesis",
   915 without referring to the original premise "!!x. P x ==> thesis" in the
   916 Isar proof context.  POTENTIAL INCOMPATIBILITY: method "assumption" is
   917 more permissive.
   918 
   919 * Isar: implicit use of prems from the Isar proof context is
   920 considered a legacy feature.  Common applications like ``have A .''
   921 may be replaced by ``have A by fact'' or ``note `A`''.  In general,
   922 referencing facts explicitly here improves readability and
   923 maintainability of proof texts.
   924 
   925 * Isar: improper proof element 'guess' is like 'obtain', but derives
   926 the obtained context from the course of reasoning!  For example:
   927 
   928   assume "EX x y. A x & B y"   -- "any previous fact"
   929   then guess x and y by clarify
   930 
   931 This technique is potentially adventurous, depending on the facts and
   932 proof tools being involved here.
   933 
   934 * Isar: known facts from the proof context may be specified as literal
   935 propositions, using ASCII back-quote syntax.  This works wherever
   936 named facts used to be allowed so far, in proof commands, proof
   937 methods, attributes etc.  Literal facts are retrieved from the context
   938 according to unification of type and term parameters.  For example,
   939 provided that "A" and "A ==> B" and "!!x. P x ==> Q x" are known
   940 theorems in the current context, then these are valid literal facts:
   941 `A` and `A ==> B` and `!!x. P x ==> Q x" as well as `P a ==> Q a` etc.
   942 
   943 There is also a proof method "fact" which does the same composition
   944 for explicit goal states, e.g. the following proof texts coincide with
   945 certain special cases of literal facts:
   946 
   947   have "A" by fact                 ==  note `A`
   948   have "A ==> B" by fact           ==  note `A ==> B`
   949   have "!!x. P x ==> Q x" by fact  ==  note `!!x. P x ==> Q x`
   950   have "P a ==> Q a" by fact       ==  note `P a ==> Q a`
   951 
   952 * Isar: ":" (colon) is no longer a symbolic identifier character in
   953 outer syntax.  Thus symbolic identifiers may be used without
   954 additional white space in declarations like this: ``assume *: A''.
   955 
   956 * Isar: 'print_facts' prints all local facts of the current context,
   957 both named and unnamed ones.
   958 
   959 * Isar: 'def' now admits simultaneous definitions, e.g.:
   960 
   961   def x == "t" and y == "u"
   962 
   963 * Isar: added command 'unfolding', which is structurally similar to
   964 'using', but affects both the goal state and facts by unfolding given
   965 rewrite rules.  Thus many occurrences of the 'unfold' method or
   966 'unfolded' attribute may be replaced by first-class proof text.
   967 
   968 * Isar: methods 'unfold' / 'fold', attributes 'unfolded' / 'folded',
   969 and command 'unfolding' now all support object-level equalities
   970 (potentially conditional).  The underlying notion of rewrite rule is
   971 analogous to the 'rule_format' attribute, but *not* that of the
   972 Simplifier (which is usually more generous).
   973 
   974 * Isar: the new attribute [rotated n] (default n = 1) rotates the
   975 premises of a theorem by n. Useful in conjunction with drule.
   976 
   977 * Isar: the goal restriction operator [N] (default N = 1) evaluates a
   978 method expression within a sandbox consisting of the first N
   979 sub-goals, which need to exist.  For example, ``simp_all [3]''
   980 simplifies the first three sub-goals, while (rule foo, simp_all)[]
   981 simplifies all new goals that emerge from applying rule foo to the
   982 originally first one.
   983 
   984 * Isar: schematic goals are no longer restricted to higher-order
   985 patterns; e.g. ``lemma "?P(?x)" by (rule TrueI)'' now works as
   986 expected.
   987 
   988 * Isar: the conclusion of a long theorem statement is now either
   989 'shows' (a simultaneous conjunction, as before), or 'obtains'
   990 (essentially a disjunction of cases with local parameters and
   991 assumptions).  The latter allows to express general elimination rules
   992 adequately; in this notation common elimination rules look like this:
   993 
   994   lemma exE:    -- "EX x. P x ==> (!!x. P x ==> thesis) ==> thesis"
   995     assumes "EX x. P x"
   996     obtains x where "P x"
   997 
   998   lemma conjE:  -- "A & B ==> (A ==> B ==> thesis) ==> thesis"
   999     assumes "A & B"
  1000     obtains A and B
  1001 
  1002   lemma disjE:  -- "A | B ==> (A ==> thesis) ==> (B ==> thesis) ==> thesis"
  1003     assumes "A | B"
  1004     obtains
  1005       A
  1006     | B
  1007 
  1008 The subsequent classical rules even refer to the formal "thesis"
  1009 explicitly:
  1010 
  1011   lemma classical:     -- "(~ thesis ==> thesis) ==> thesis"
  1012     obtains "~ thesis"
  1013 
  1014   lemma Peirce's_Law:  -- "((thesis ==> something) ==> thesis) ==> thesis"
  1015     obtains "thesis ==> something"
  1016 
  1017 The actual proof of an 'obtains' statement is analogous to that of the
  1018 Isar proof element 'obtain', only that there may be several cases.
  1019 Optional case names may be specified in parentheses; these will be
  1020 available both in the present proof and as annotations in the
  1021 resulting rule, for later use with the 'cases' method (cf. attribute
  1022 case_names).
  1023 
  1024 * Isar: the assumptions of a long theorem statement are available as
  1025 "assms" fact in the proof context.  This is more appropriate than the
  1026 (historical) "prems", which refers to all assumptions of the current
  1027 context, including those from the target locale, proof body etc.
  1028 
  1029 * Isar: 'print_statement' prints theorems from the current theory or
  1030 proof context in long statement form, according to the syntax of a
  1031 top-level lemma.
  1032 
  1033 * Isar: 'obtain' takes an optional case name for the local context
  1034 introduction rule (default "that").
  1035 
  1036 * Isar: removed obsolete 'concl is' patterns.  INCOMPATIBILITY, use
  1037 explicit (is "_ ==> ?foo") in the rare cases where this still happens
  1038 to occur.
  1039 
  1040 * Pure: syntax "CONST name" produces a fully internalized constant
  1041 according to the current context.  This is particularly useful for
  1042 syntax translations that should refer to internal constant
  1043 representations independently of name spaces.
  1044 
  1045 * Pure: syntax constant for foo (binder "FOO ") is called "foo_binder"
  1046 instead of "FOO ". This allows multiple binder declarations to coexist
  1047 in the same context.  INCOMPATIBILITY.
  1048 
  1049 * Isar/locales: 'notation' provides a robust interface to the 'syntax'
  1050 primitive that also works in a locale context (both for constants and
  1051 fixed variables). Type declaration and internal syntactic representation
  1052 of given constants retrieved from the context. Likewise, the
  1053 'no_notation' command allows to remove given syntax annotations from the
  1054 current context.
  1055 
  1056 * Isar/locales: new derived specification elements 'axiomatization',
  1057 'definition', 'abbreviation', which support type-inference, admit
  1058 object-level specifications (equality, equivalence).  See also the
  1059 isar-ref manual.  Examples:
  1060 
  1061   axiomatization
  1062     eq  (infix "===" 50) where
  1063     eq_refl: "x === x" and eq_subst: "x === y ==> P x ==> P y"
  1064 
  1065   definition "f x y = x + y + 1"
  1066   definition g where "g x = f x x"
  1067 
  1068   abbreviation
  1069     neq  (infix "=!=" 50) where
  1070     "x =!= y == ~ (x === y)"
  1071 
  1072 These specifications may be also used in a locale context.  Then the
  1073 constants being introduced depend on certain fixed parameters, and the
  1074 constant name is qualified by the locale base name.  An internal
  1075 abbreviation takes care for convenient input and output, making the
  1076 parameters implicit and using the original short name.  See also
  1077 src/HOL/ex/Abstract_NAT.thy for an example of deriving polymorphic
  1078 entities from a monomorphic theory.
  1079 
  1080 Presently, abbreviations are only available 'in' a target locale, but
  1081 not inherited by general import expressions.  Also note that
  1082 'abbreviation' may be used as a type-safe replacement for 'syntax' +
  1083 'translations' in common applications.  The "no_abbrevs" print mode
  1084 prevents folding of abbreviations in term output.
  1085 
  1086 Concrete syntax is attached to specified constants in internal form,
  1087 independently of name spaces.  The parse tree representation is
  1088 slightly different -- use 'notation' instead of raw 'syntax', and
  1089 'translations' with explicit "CONST" markup to accommodate this.
  1090 
  1091 * Pure/Isar: unified syntax for new-style specification mechanisms
  1092 (e.g.  'definition', 'abbreviation', or 'inductive' in HOL) admits
  1093 full type inference and dummy patterns ("_").  For example:
  1094 
  1095   definition "K x _ = x"
  1096 
  1097   inductive conj for A B
  1098   where "A ==> B ==> conj A B"
  1099 
  1100 * Pure: command 'print_abbrevs' prints all constant abbreviations of
  1101 the current context.  Print mode "no_abbrevs" prevents inversion of
  1102 abbreviations on output.
  1103 
  1104 * Isar/locales: improved parameter handling: use of locales "var" and
  1105 "struct" no longer necessary; - parameter renamings are no longer
  1106 required to be injective.  For example, this allows to define
  1107 endomorphisms as locale endom = homom mult mult h.
  1108 
  1109 * Isar/locales: changed the way locales with predicates are defined.
  1110 Instead of accumulating the specification, the imported expression is
  1111 now an interpretation.  INCOMPATIBILITY: different normal form of
  1112 locale expressions.  In particular, in interpretations of locales with
  1113 predicates, goals repesenting already interpreted fragments are not
  1114 removed automatically.  Use methods `intro_locales' and
  1115 `unfold_locales'; see below.
  1116 
  1117 * Isar/locales: new methods `intro_locales' and `unfold_locales'
  1118 provide backward reasoning on locales predicates.  The methods are
  1119 aware of interpretations and discharge corresponding goals.
  1120 `intro_locales' is less aggressive then `unfold_locales' and does not
  1121 unfold predicates to assumptions.
  1122 
  1123 * Isar/locales: the order in which locale fragments are accumulated
  1124 has changed.  This enables to override declarations from fragments due
  1125 to interpretations -- for example, unwanted simp rules.
  1126 
  1127 * Isar/locales: interpretation in theories and proof contexts has been
  1128 extended.  One may now specify (and prove) equations, which are
  1129 unfolded in interpreted theorems.  This is useful for replacing
  1130 defined concepts (constants depending on locale parameters) by
  1131 concepts already existing in the target context.  Example:
  1132 
  1133   interpretation partial_order ["op <= :: [int, int] => bool"]
  1134     where "partial_order.less (op <=) (x::int) y = (x < y)"
  1135 
  1136 Typically, the constant `partial_order.less' is created by a
  1137 definition specification element in the context of locale
  1138 partial_order.
  1139 
  1140 * Method "induct": improved internal context management to support
  1141 local fixes and defines on-the-fly. Thus explicit meta-level
  1142 connectives !!  and ==> are rarely required anymore in inductive goals
  1143 (using object-logic connectives for this purpose has been long
  1144 obsolete anyway). Common proof patterns are explained in
  1145 src/HOL/Induct/Common_Patterns.thy, see also
  1146 src/HOL/Isar_examples/Puzzle.thy and src/HOL/Lambda for realistic
  1147 examples.
  1148 
  1149 * Method "induct": improved handling of simultaneous goals. Instead of
  1150 introducing object-level conjunction, the statement is now split into
  1151 several conclusions, while the corresponding symbolic cases are nested
  1152 accordingly. INCOMPATIBILITY, proofs need to be structured explicitly,
  1153 see src/HOL/Induct/Common_Patterns.thy, for example.
  1154 
  1155 * Method "induct": mutual induction rules are now specified as a list
  1156 of rule sharing the same induction cases. HOL packages usually provide
  1157 foo_bar.inducts for mutually defined items foo and bar (e.g. inductive
  1158 predicates/sets or datatypes). INCOMPATIBILITY, users need to specify
  1159 mutual induction rules differently, i.e. like this:
  1160 
  1161   (induct rule: foo_bar.inducts)
  1162   (induct set: foo bar)
  1163   (induct pred: foo bar)
  1164   (induct type: foo bar)
  1165 
  1166 The ML function ProjectRule.projections turns old-style rules into the
  1167 new format.
  1168 
  1169 * Method "coinduct": dual of induction, see
  1170 src/HOL/Library/Coinductive_List.thy for various examples.
  1171 
  1172 * Method "cases", "induct", "coinduct": the ``(open)'' option is
  1173 considered a legacy feature.
  1174 
  1175 * Attribute "symmetric" produces result with standardized schematic
  1176 variables (index 0).  Potential INCOMPATIBILITY.
  1177 
  1178 * Simplifier: by default the simplifier trace only shows top level
  1179 rewrites now. That is, trace_simp_depth_limit is set to 1 by
  1180 default. Thus there is less danger of being flooded by the trace. The
  1181 trace indicates where parts have been suppressed.
  1182   
  1183 * Provers/classical: removed obsolete classical version of elim_format
  1184 attribute; classical elim/dest rules are now treated uniformly when
  1185 manipulating the claset.
  1186 
  1187 * Provers/classical: stricter checks to ensure that supplied intro,
  1188 dest and elim rules are well-formed; dest and elim rules must have at
  1189 least one premise.
  1190 
  1191 * Provers/classical: attributes dest/elim/intro take an optional
  1192 weight argument for the rule (just as the Pure versions).  Weights are
  1193 ignored by automated tools, but determine the search order of single
  1194 rule steps.
  1195 
  1196 * Syntax: input syntax now supports dummy variable binding "%_. b",
  1197 where the body does not mention the bound variable.  Note that dummy
  1198 patterns implicitly depend on their context of bounds, which makes
  1199 "{_. _}" match any set comprehension as expected.  Potential
  1200 INCOMPATIBILITY -- parse translations need to cope with syntactic
  1201 constant "_idtdummy" in the binding position.
  1202 
  1203 * Syntax: removed obsolete syntactic constant "_K" and its associated
  1204 parse translation.  INCOMPATIBILITY -- use dummy abstraction instead,
  1205 for example "A -> B" => "Pi A (%_. B)".
  1206 
  1207 * Pure: 'class_deps' command visualizes the subclass relation, using
  1208 the graph browser tool.
  1209 
  1210 * Pure: 'print_theory' now suppresses certain internal declarations by
  1211 default; use '!' option for full details.
  1212 
  1213 
  1214 *** HOL ***
  1215 
  1216 * Method "metis" proves goals by applying the Metis general-purpose
  1217 resolution prover (see also http://gilith.com/software/metis/).
  1218 Examples are in the directory MetisExamples.  WARNING: the
  1219 Isabelle/HOL-Metis integration does not yet work properly with
  1220 multi-threading.
  1221   
  1222 * Command 'sledgehammer' invokes external automatic theorem provers as
  1223 background processes.  It generates calls to the "metis" method if
  1224 successful. These can be pasted into the proof.  Users do not have to
  1225 wait for the automatic provers to return.  WARNING: does not really
  1226 work with multi-threading.
  1227 
  1228 * New "auto_quickcheck" feature tests outermost goal statements for
  1229 potential counter-examples.  Controlled by ML references
  1230 auto_quickcheck (default true) and auto_quickcheck_time_limit (default
  1231 5000 milliseconds).  Fails silently if statements is outside of
  1232 executable fragment, or any other codgenerator problem occurs.
  1233 
  1234 * New constant "undefined" with axiom "undefined x = undefined".
  1235 
  1236 * Added class "HOL.eq", allowing for code generation with polymorphic
  1237 equality.
  1238 
  1239 * Some renaming of class constants due to canonical name prefixing in
  1240 the new 'class' package:
  1241 
  1242     HOL.abs ~> HOL.abs_class.abs
  1243     HOL.divide ~> HOL.divide_class.divide
  1244     0 ~> HOL.zero_class.zero
  1245     1 ~> HOL.one_class.one
  1246     op + ~> HOL.plus_class.plus
  1247     op - ~> HOL.minus_class.minus
  1248     uminus ~> HOL.minus_class.uminus
  1249     op * ~> HOL.times_class.times
  1250     op < ~> HOL.ord_class.less
  1251     op <= > HOL.ord_class.less_eq
  1252     Nat.power ~> Power.power_class.power
  1253     Nat.size ~> Nat.size_class.size
  1254     Numeral.number_of ~> Numeral.number_class.number_of
  1255     FixedPoint.Inf ~> Lattices.complete_lattice_class.Inf
  1256     FixedPoint.Sup ~> Lattices.complete_lattice_class.Sup
  1257     Orderings.min ~> Orderings.ord_class.min
  1258     Orderings.max ~> Orderings.ord_class.max
  1259     Divides.op div ~> Divides.div_class.div
  1260     Divides.op mod ~> Divides.div_class.mod
  1261     Divides.op dvd ~> Divides.div_class.dvd
  1262 
  1263 INCOMPATIBILITY.  Adaptions may be required in the following cases:
  1264 
  1265 a) User-defined constants using any of the names "plus", "minus",
  1266 "times", "less" or "less_eq". The standard syntax translations for
  1267 "+", "-" and "*" may go wrong.  INCOMPATIBILITY: use more specific
  1268 names.
  1269 
  1270 b) Variables named "plus", "minus", "times", "less", "less_eq"
  1271 INCOMPATIBILITY: use more specific names.
  1272 
  1273 c) Permutative equations (e.g. "a + b = b + a")
  1274 Since the change of names also changes the order of terms, permutative
  1275 rewrite rules may get applied in a different order. Experience shows
  1276 that this is rarely the case (only two adaptions in the whole Isabelle
  1277 distribution).  INCOMPATIBILITY: rewrite proofs
  1278 
  1279 d) ML code directly refering to constant names
  1280 This in general only affects hand-written proof tactics, simprocs and
  1281 so on.  INCOMPATIBILITY: grep your sourcecode and replace names.
  1282 Consider using @{const_name} antiquotation.
  1283 
  1284 * New class "default" with associated constant "default".
  1285 
  1286 * Function "sgn" is now overloaded and available on int, real, complex
  1287 (and other numeric types), using class "sgn".  Two possible defs of
  1288 sgn are given as equational assumptions in the classes sgn_if and
  1289 sgn_div_norm; ordered_idom now also inherits from sgn_if.
  1290 INCOMPATIBILITY.
  1291 
  1292 * Locale "partial_order" now unified with class "order" (cf. theory
  1293 Orderings), added parameter "less".  INCOMPATIBILITY.
  1294 
  1295 * Renamings in classes "order" and "linorder": facts "refl", "trans" and
  1296 "cases" to "order_refl", "order_trans" and "linorder_cases", to avoid
  1297 clashes with HOL "refl" and "trans".  INCOMPATIBILITY.
  1298 
  1299 * Classes "order" and "linorder": potential INCOMPATIBILITY due to
  1300 changed order of proof goals in instance proofs.
  1301 
  1302 * The transitivity reasoner for partial and linear orders is set up
  1303 for classes "order" and "linorder".  Instances of the reasoner are available
  1304 in all contexts importing or interpreting the corresponding locales.
  1305 Method "order" invokes the reasoner separately; the reasoner
  1306 is also integrated with the Simplifier as a solver.  Diagnostic
  1307 command 'print_orders' shows the available instances of the reasoner
  1308 in the current context.
  1309 
  1310 * Localized monotonicity predicate in theory "Orderings"; integrated
  1311 lemmas max_of_mono and min_of_mono with this predicate.
  1312 INCOMPATIBILITY.
  1313 
  1314 * Formulation of theorem "dense" changed slightly due to integration
  1315 with new class dense_linear_order.
  1316 
  1317 * Uniform lattice theory development in HOL.
  1318 
  1319     constants "meet" and "join" now named "inf" and "sup"
  1320     constant "Meet" now named "Inf"
  1321 
  1322     classes "meet_semilorder" and "join_semilorder" now named
  1323       "lower_semilattice" and "upper_semilattice"
  1324     class "lorder" now named "lattice"
  1325     class "comp_lat" now named "complete_lattice"
  1326 
  1327     Instantiation of lattice classes allows explicit definitions
  1328     for "inf" and "sup" operations (or "Inf" and "Sup" for complete lattices).
  1329 
  1330   INCOMPATIBILITY.  Theorem renames:
  1331 
  1332     meet_left_le            ~> inf_le1
  1333     meet_right_le           ~> inf_le2
  1334     join_left_le            ~> sup_ge1
  1335     join_right_le           ~> sup_ge2
  1336     meet_join_le            ~> inf_sup_ord
  1337     le_meetI                ~> le_infI
  1338     join_leI                ~> le_supI
  1339     le_meet                 ~> le_inf_iff
  1340     le_join                 ~> ge_sup_conv
  1341     meet_idempotent         ~> inf_idem
  1342     join_idempotent         ~> sup_idem
  1343     meet_comm               ~> inf_commute
  1344     join_comm               ~> sup_commute
  1345     meet_leI1               ~> le_infI1
  1346     meet_leI2               ~> le_infI2
  1347     le_joinI1               ~> le_supI1
  1348     le_joinI2               ~> le_supI2
  1349     meet_assoc              ~> inf_assoc
  1350     join_assoc              ~> sup_assoc
  1351     meet_left_comm          ~> inf_left_commute
  1352     meet_left_idempotent    ~> inf_left_idem
  1353     join_left_comm          ~> sup_left_commute
  1354     join_left_idempotent    ~> sup_left_idem
  1355     meet_aci                ~> inf_aci
  1356     join_aci                ~> sup_aci
  1357     le_def_meet             ~> le_iff_inf
  1358     le_def_join             ~> le_iff_sup
  1359     join_absorp2            ~> sup_absorb2
  1360     join_absorp1            ~> sup_absorb1
  1361     meet_absorp1            ~> inf_absorb1
  1362     meet_absorp2            ~> inf_absorb2
  1363     meet_join_absorp        ~> inf_sup_absorb
  1364     join_meet_absorp        ~> sup_inf_absorb
  1365     distrib_join_le         ~> distrib_sup_le
  1366     distrib_meet_le         ~> distrib_inf_le
  1367 
  1368     add_meet_distrib_left   ~> add_inf_distrib_left
  1369     add_join_distrib_left   ~> add_sup_distrib_left
  1370     is_join_neg_meet        ~> is_join_neg_inf
  1371     is_meet_neg_join        ~> is_meet_neg_sup
  1372     add_meet_distrib_right  ~> add_inf_distrib_right
  1373     add_join_distrib_right  ~> add_sup_distrib_right
  1374     add_meet_join_distribs  ~> add_sup_inf_distribs
  1375     join_eq_neg_meet        ~> sup_eq_neg_inf
  1376     meet_eq_neg_join        ~> inf_eq_neg_sup
  1377     add_eq_meet_join        ~> add_eq_inf_sup
  1378     meet_0_imp_0            ~> inf_0_imp_0
  1379     join_0_imp_0            ~> sup_0_imp_0
  1380     meet_0_eq_0             ~> inf_0_eq_0
  1381     join_0_eq_0             ~> sup_0_eq_0
  1382     neg_meet_eq_join        ~> neg_inf_eq_sup
  1383     neg_join_eq_meet        ~> neg_sup_eq_inf
  1384     join_eq_if              ~> sup_eq_if
  1385 
  1386     mono_meet               ~> mono_inf
  1387     mono_join               ~> mono_sup
  1388     meet_bool_eq            ~> inf_bool_eq
  1389     join_bool_eq            ~> sup_bool_eq
  1390     meet_fun_eq             ~> inf_fun_eq
  1391     join_fun_eq             ~> sup_fun_eq
  1392     meet_set_eq             ~> inf_set_eq
  1393     join_set_eq             ~> sup_set_eq
  1394     meet1_iff               ~> inf1_iff
  1395     meet2_iff               ~> inf2_iff
  1396     meet1I                  ~> inf1I
  1397     meet2I                  ~> inf2I
  1398     meet1D1                 ~> inf1D1
  1399     meet2D1                 ~> inf2D1
  1400     meet1D2                 ~> inf1D2
  1401     meet2D2                 ~> inf2D2
  1402     meet1E                  ~> inf1E
  1403     meet2E                  ~> inf2E
  1404     join1_iff               ~> sup1_iff
  1405     join2_iff               ~> sup2_iff
  1406     join1I1                 ~> sup1I1
  1407     join2I1                 ~> sup2I1
  1408     join1I1                 ~> sup1I1
  1409     join2I2                 ~> sup1I2
  1410     join1CI                 ~> sup1CI
  1411     join2CI                 ~> sup2CI
  1412     join1E                  ~> sup1E
  1413     join2E                  ~> sup2E
  1414 
  1415     is_meet_Meet            ~> is_meet_Inf
  1416     Meet_bool_def           ~> Inf_bool_def
  1417     Meet_fun_def            ~> Inf_fun_def
  1418     Meet_greatest           ~> Inf_greatest
  1419     Meet_lower              ~> Inf_lower
  1420     Meet_set_def            ~> Inf_set_def
  1421 
  1422     Sup_def                 ~> Sup_Inf
  1423     Sup_bool_eq             ~> Sup_bool_def
  1424     Sup_fun_eq              ~> Sup_fun_def
  1425     Sup_set_eq              ~> Sup_set_def
  1426 
  1427     listsp_meetI            ~> listsp_infI
  1428     listsp_meet_eq          ~> listsp_inf_eq
  1429 
  1430     meet_min                ~> inf_min
  1431     join_max                ~> sup_max
  1432 
  1433 * Added syntactic class "size"; overloaded constant "size" now has
  1434 type "'a::size ==> bool"
  1435 
  1436 * Internal reorganisation of `size' of datatypes: size theorems
  1437 "foo.size" are no longer subsumed by "foo.simps" (but are still
  1438 simplification rules by default!); theorems "prod.size" now named
  1439 "*.size".
  1440 
  1441 * Class "div" now inherits from class "times" rather than "type".
  1442 INCOMPATIBILITY.
  1443 
  1444 * HOL/Finite_Set: "name-space" locales Lattice, Distrib_lattice,
  1445 Linorder etc.  have disappeared; operations defined in terms of
  1446 fold_set now are named Inf_fin, Sup_fin.  INCOMPATIBILITY.
  1447 
  1448 * HOL/Nat: neq0_conv no longer declared as iff.  INCOMPATIBILITY.
  1449 
  1450 * HOL-Word: New extensive library and type for generic, fixed size
  1451 machine words, with arithemtic, bit-wise, shifting and rotating
  1452 operations, reflection into int, nat, and bool lists, automation for
  1453 linear arithmetic (by automatic reflection into nat or int), including
  1454 lemmas on overflow and monotonicity.  Instantiated to all appropriate
  1455 arithmetic type classes, supporting automatic simplification of
  1456 numerals on all operations.
  1457 
  1458 * Library/Boolean_Algebra: locales for abstract boolean algebras.
  1459 
  1460 * Library/Numeral_Type: numbers as types, e.g. TYPE(32).
  1461 
  1462 * Code generator library theories:
  1463   - Code_Integer represents HOL integers by big integer literals in target
  1464     languages.
  1465   - Code_Char represents HOL characters by character literals in target
  1466     languages.
  1467   - Code_Char_chr like Code_Char, but also offers treatment of character
  1468     codes; includes Code_Integer.
  1469   - Executable_Set allows to generate code for finite sets using lists.
  1470   - Executable_Rat implements rational numbers as triples (sign, enumerator,
  1471     denominator).
  1472   - Executable_Real implements a subset of real numbers, namly those
  1473     representable by rational numbers.
  1474   - Efficient_Nat implements natural numbers by integers, which in general will
  1475     result in higher efficency; pattern matching with 0/Suc is eliminated;
  1476     includes Code_Integer.
  1477   - Code_Index provides an additional datatype index which is mapped to
  1478     target-language built-in integers.
  1479   - Code_Message provides an additional datatype message_string which is isomorphic to
  1480     strings; messages are mapped to target-language strings.
  1481 
  1482 * New package for inductive predicates
  1483 
  1484   An n-ary predicate p with m parameters z_1, ..., z_m can now be defined via
  1485 
  1486     inductive
  1487       p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1488       for z_1 :: U_1 and ... and z_n :: U_m
  1489     where
  1490       rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1491     | ...
  1492 
  1493   with full support for type-inference, rather than
  1494 
  1495     consts s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1496 
  1497     abbreviation p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1498     where "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1499 
  1500     inductive "s z_1 ... z_m"
  1501     intros
  1502       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1503       ...
  1504 
  1505   For backward compatibility, there is a wrapper allowing inductive
  1506   sets to be defined with the new package via
  1507 
  1508     inductive_set
  1509       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1510       for z_1 :: U_1 and ... and z_n :: U_m
  1511     where
  1512       rule_1: "... ==> (t_1_1, ..., t_1_n) : s z_1 ... z_m"
  1513     | ...
  1514 
  1515   or
  1516 
  1517     inductive_set
  1518       s :: "U_1 => ... => U_m => (T_1 * ... * T_n) set"
  1519       and p :: "U_1 => ... => U_m => T_1 => ... => T_n => bool"
  1520       for z_1 :: U_1 and ... and z_n :: U_m
  1521     where
  1522       "p z_1 ... z_m x_1 ... x_n == (x_1, ..., x_n) : s z_1 ... z_m"
  1523     | rule_1: "... ==> p z_1 ... z_m t_1_1 ... t_1_n"
  1524     | ...
  1525 
  1526   if the additional syntax "p ..." is required.
  1527 
  1528   Numerous examples can be found in the subdirectories src/HOL/Auth,
  1529   src/HOL/Bali, src/HOL/Induct, and src/HOL/MicroJava.
  1530 
  1531   INCOMPATIBILITIES:
  1532 
  1533   - Since declaration and definition of inductive sets or predicates
  1534     is no longer separated, abbreviations involving the newly
  1535     introduced sets or predicates must be specified together with the
  1536     introduction rules after the 'where' keyword (see above), rather
  1537     than before the actual inductive definition.
  1538 
  1539   - The variables in induction and elimination rules are now
  1540     quantified in the order of their occurrence in the introduction
  1541     rules, rather than in alphabetical order. Since this may break
  1542     some proofs, these proofs either have to be repaired, e.g. by
  1543     reordering the variables a_i_1 ... a_i_{k_i} in Isar 'case'
  1544     statements of the form
  1545 
  1546       case (rule_i a_i_1 ... a_i_{k_i})
  1547 
  1548     or the old order of quantification has to be restored by explicitly adding
  1549     meta-level quantifiers in the introduction rules, i.e.
  1550 
  1551       | rule_i: "!!a_i_1 ... a_i_{k_i}. ... ==> p z_1 ... z_m t_i_1 ... t_i_n"
  1552 
  1553   - The format of the elimination rules is now
  1554 
  1555       p z_1 ... z_m x_1 ... x_n ==>
  1556         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1557         ==> ... ==> P
  1558 
  1559     for predicates and
  1560 
  1561       (x_1, ..., x_n) : s z_1 ... z_m ==>
  1562         (!!a_1_1 ... a_1_{k_1}. x_1 = t_1_1 ==> ... ==> x_n = t_1_n ==> ... ==> P)
  1563         ==> ... ==> P
  1564 
  1565     for sets rather than
  1566 
  1567       x : s z_1 ... z_m ==>
  1568         (!!a_1_1 ... a_1_{k_1}. x = (t_1_1, ..., t_1_n) ==> ... ==> P)
  1569         ==> ... ==> P
  1570 
  1571     This may require terms in goals to be expanded to n-tuples
  1572     (e.g. using case_tac or simplification with the split_paired_all
  1573     rule) before the above elimination rule is applicable.
  1574 
  1575   - The elimination or case analysis rules for (mutually) inductive
  1576     sets or predicates are now called "p_1.cases" ... "p_k.cases". The
  1577     list of rules "p_1_..._p_k.elims" is no longer available.
  1578 
  1579 * New package "function"/"fun" for general recursive functions,
  1580 supporting mutual and nested recursion, definitions in local contexts,
  1581 more general pattern matching and partiality. See HOL/ex/Fundefs.thy
  1582 for small examples, and the separate tutorial on the function
  1583 package. The old recdef "package" is still available as before, but
  1584 users are encouraged to use the new package.
  1585 
  1586 * Method "lexicographic_order" automatically synthesizes termination
  1587 relations as lexicographic combinations of size measures. 
  1588 
  1589 * Case-expressions allow arbitrary constructor-patterns (including
  1590 "_") and take their order into account, like in functional
  1591 programming.  Internally, this is translated into nested
  1592 case-expressions; missing cases are added and mapped to the predefined
  1593 constant "undefined". In complicated cases printing may no longer show
  1594 the original input but the internal form. Lambda-abstractions allow
  1595 the same form of pattern matching: "% pat1 => e1 | ..." is an
  1596 abbreviation for "%x. case x of pat1 => e1 | ..." where x is a new
  1597 variable.
  1598 
  1599 * IntDef: The constant "int :: nat => int" has been removed; now "int"
  1600 is an abbreviation for "of_nat :: nat => int". The simplification
  1601 rules for "of_nat" have been changed to work like "int" did
  1602 previously.  Potential INCOMPATIBILITY:
  1603   - "of_nat (Suc m)" simplifies to "1 + of_nat m" instead of "of_nat m + 1"
  1604   - of_nat_diff and of_nat_mult are no longer default simp rules
  1605 
  1606 * Method "algebra" solves polynomial equations over (semi)rings using
  1607 Groebner bases. The (semi)ring structure is defined by locales and the
  1608 tool setup depends on that generic context. Installing the method for
  1609 a specific type involves instantiating the locale and possibly adding
  1610 declarations for computation on the coefficients.  The method is
  1611 already instantiated for natural numbers and for the axiomatic class
  1612 of idoms with numerals.  See also the paper by Chaieb and Wenzel at
  1613 CALCULEMUS 2007 for the general principles underlying this
  1614 architecture of context-aware proof-tools.
  1615 
  1616 * Method "ferrack" implements quantifier elimination over
  1617 special-purpose dense linear orders using locales (analogous to
  1618 "algebra"). The method is already installed for class
  1619 {ordered_field,recpower,number_ring} which subsumes real, hyperreal,
  1620 rat, etc.
  1621 
  1622 * Former constant "List.op @" now named "List.append".  Use ML
  1623 antiquotations @{const_name List.append} or @{term " ... @ ... "} to
  1624 circumvent possible incompatibilities when working on ML level.
  1625 
  1626 * primrec: missing cases mapped to "undefined" instead of "arbitrary".
  1627 
  1628 * New function listsum :: 'a list => 'a for arbitrary monoids.
  1629 Special syntax: "SUM x <- xs. f x" (and latex variants)
  1630 
  1631 * New syntax for Haskell-like list comprehension (input only), eg.
  1632 [(x,y). x <- xs, y <- ys, x ~= y], see also src/HOL/List.thy.
  1633 
  1634 * The special syntax for function "filter" has changed from [x :
  1635 xs. P] to [x <- xs. P] to avoid an ambiguity caused by list
  1636 comprehension syntax, and for uniformity.  INCOMPATIBILITY.
  1637 
  1638 * [a..b] is now defined for arbitrary linear orders.  It used to be
  1639 defined on nat only, as an abbreviation for [a..<Suc b]
  1640 INCOMPATIBILITY.
  1641 
  1642 * Renamed lemma "set_take_whileD"  to "set_takeWhileD".
  1643 
  1644 * New functions "sorted" and "sort" in src/HOL/List.thy.
  1645 
  1646 * New lemma collection field_simps (an extension of ring_simps) for
  1647 manipulating (in)equations involving division. Multiplies with all
  1648 denominators that can be proved to be non-zero (in equations) or
  1649 positive/negative (in inequations).
  1650 
  1651 * Lemma collections ring_eq_simps, group_eq_simps and ring_distrib
  1652 have been improved and renamed to ring_simps, group_simps and
  1653 ring_distribs.  Removed lemmas field_xyz in theory Ring_and_Field
  1654 because they were subsumed by lemmas xyz.  INCOMPATIBILITY.
  1655 
  1656 * Theory Library/Commutative_Ring: switched from recdef to function
  1657 package; constants add, mul, pow now curried.  Infix syntax for
  1658 algebraic operations.
  1659 
  1660 * Dropped redundant lemma def_imp_eq in favor of meta_eq_to_obj_eq.
  1661 INCOMPATIBILITY.
  1662 
  1663 * Dropped redundant lemma if_def2 in favor of if_bool_eq_conj.
  1664 INCOMPATIBILITY.
  1665 
  1666 * HOL/records: generalised field-update to take a function on the
  1667 field rather than the new value: r(|A := x|) is translated to A_update
  1668 (K x) r The K-combinator that is internally used is called K_record.
  1669 INCOMPATIBILITY: Usage of the plain update functions has to be
  1670 adapted.
  1671  
  1672 * Class "semiring_0" now contains annihilation axioms x * 0 = 0 and 0
  1673 * x = 0, which are required for a semiring.  Richer structures do not
  1674 inherit from semiring_0 anymore, because this property is a theorem
  1675 there, not an axiom.  INCOMPATIBILITY: In instances of semiring_0,
  1676 there is more to prove, but this is mostly trivial.
  1677 
  1678 * Class "recpower" is generalized to arbitrary monoids, not just
  1679 commutative semirings.  INCOMPATIBILITY: may need to incorporate
  1680 commutativity or semiring properties additionally.
  1681 
  1682 * Constant "List.list_all2" in List.thy now uses authentic syntax.
  1683 INCOMPATIBILITY: translations containing list_all2 may go wrong,
  1684 better use 'abbreviation'.
  1685 
  1686 * Renamed constant "List.op mem" to "List.member".  INCOMPATIBILITY.
  1687 
  1688 * Numeral syntax: type 'bin' which was a mere type copy of 'int' has
  1689 been abandoned in favour of plain 'int'.  INCOMPATIBILITY --
  1690 significant changes for setting up numeral syntax for types:
  1691   - New constants Numeral.pred and Numeral.succ instead
  1692       of former Numeral.bin_pred and Numeral.bin_succ.
  1693   - Use integer operations instead of bin_add, bin_mult and so on.
  1694   - Numeral simplification theorems named Numeral.numeral_simps instead of Bin_simps.
  1695   - ML structure Bin_Simprocs now named Int_Numeral_Base_Simprocs.
  1696 
  1697 See src/HOL/Integ/IntArith.thy for an example setup.
  1698 
  1699 * Command 'normal_form' computes the normal form of a term that may
  1700 contain free variables.  For example ``normal_form "rev [a, b, c]"''
  1701 produces ``[b, c, a]'' (without proof).  This command is suitable for
  1702 heavy-duty computations because the functions are compiled to ML
  1703 first.  Correspondingly, a method "normalization" is provided.  See
  1704 further src/HOL/ex/NormalForm.thy and src/Tools/nbe.ML.
  1705 
  1706 * Alternative iff syntax "A <-> B" for equality on bool (with priority
  1707 25 like -->); output depends on the "iff" print_mode, the default is
  1708 "A = B" (with priority 50).
  1709 
  1710 * Relations less (<) and less_eq (<=) are also available on type bool.
  1711 Modified syntax to disallow nesting without explicit parentheses,
  1712 e.g. "(x < y) < z" or "x < (y < z)", but NOT "x < y < z".  Potential
  1713 INCOMPATIBILITY.
  1714 
  1715 * "LEAST x:A. P" expands to "LEAST x. x:A & P" (input only).
  1716 
  1717 * Relation composition operator "op O" now has precedence 75 and binds
  1718 stronger than union and intersection. INCOMPATIBILITY.
  1719 
  1720 * The old set interval syntax "{m..n(}" (and relatives) has been
  1721 removed.  Use "{m..<n}" (and relatives) instead.
  1722 
  1723 * In the context of the assumption "~(s = t)" the Simplifier rewrites
  1724 "t = s" to False (by simproc "neq").  INCOMPATIBILITY, consider using
  1725 ``declare [[simproc del: neq]]''.
  1726 
  1727 * Simplifier: "m dvd n" where m and n are numbers is evaluated to
  1728 True/False.
  1729 
  1730 * Theorem Cons_eq_map_conv no longer declared as "simp".
  1731 
  1732 * Theorem setsum_mult renamed to setsum_right_distrib.
  1733 
  1734 * Prefer ex1I over ex_ex1I in single-step reasoning, e.g. by the
  1735 ``rule'' method.
  1736 
  1737 * Reimplemented methods "sat" and "satx", with several improvements:
  1738 goals no longer need to be stated as "<prems> ==> False", equivalences
  1739 (i.e. "=" on type bool) are handled, variable names of the form
  1740 "lit_<n>" are no longer reserved, significant speedup.
  1741 
  1742 * Methods "sat" and "satx" can now replay MiniSat proof traces.
  1743 zChaff is still supported as well.
  1744 
  1745 * 'inductive' and 'datatype': provide projections of mutual rules,
  1746 bundled as foo_bar.inducts;
  1747 
  1748 * Library: moved theories Parity, GCD, Binomial, Infinite_Set to
  1749 Library.
  1750 
  1751 * Library: moved theory Accessible_Part to main HOL.
  1752 
  1753 * Library: added theory Coinductive_List of potentially infinite lists
  1754 as greatest fixed-point.
  1755 
  1756 * Library: added theory AssocList which implements (finite) maps as
  1757 association lists.
  1758 
  1759 * Method "evaluation" solves goals (i.e. a boolean expression)
  1760 efficiently by compiling it to ML.  The goal is "proved" (via an
  1761 oracle) if it evaluates to True.
  1762 
  1763 * Linear arithmetic now splits certain operators (e.g. min, max, abs)
  1764 also when invoked by the simplifier.  This results in the Simplifier
  1765 being more powerful on arithmetic goals.  INCOMPATIBILITY.
  1766 Configuration option fast_arith_split_limit=0 recovers the old
  1767 behavior.
  1768 
  1769 * Support for hex (0x20) and binary (0b1001) numerals.
  1770 
  1771 * New method: reify eqs (t), where eqs are equations for an
  1772 interpretation I :: 'a list => 'b => 'c and t::'c is an optional
  1773 parameter, computes a term s::'b and a list xs::'a list and proves the
  1774 theorem I xs s = t. This is also known as reification or quoting. The
  1775 resulting theorem is applied to the subgoal to substitute t with I xs
  1776 s.  If t is omitted, the subgoal itself is reified.
  1777 
  1778 * New method: reflection corr_thm eqs (t). The parameters eqs and (t)
  1779 are as explained above. corr_thm is a theorem for I vs (f t) = I vs t,
  1780 where f is supposed to be a computable function (in the sense of code
  1781 generattion). The method uses reify to compute s and xs as above then
  1782 applies corr_thm and uses normalization by evaluation to "prove" f s =
  1783 r and finally gets the theorem t = r, which is again applied to the
  1784 subgoal. An Example is available in src/HOL/ex/ReflectionEx.thy.
  1785 
  1786 * Reflection: Automatic reification now handels binding, an example is
  1787 available in src/HOL/ex/ReflectionEx.thy
  1788 
  1789 * HOL-Statespace: ``State Spaces: The Locale Way'' introduces a
  1790 command 'statespace' that is similar to 'record', but introduces an
  1791 abstract specification based on the locale infrastructure instead of
  1792 HOL types.  This leads to extra flexibility in composing state spaces,
  1793 in particular multiple inheritance and renaming of components.
  1794 
  1795 
  1796 *** HOL-Complex ***
  1797 
  1798 * Hyperreal: Functions root and sqrt are now defined on negative real
  1799 inputs so that root n (- x) = - root n x and sqrt (- x) = - sqrt x.
  1800 Nonnegativity side conditions have been removed from many lemmas, so
  1801 that more subgoals may now be solved by simplification; potential
  1802 INCOMPATIBILITY.
  1803 
  1804 * Real: new type classes formalize real normed vector spaces and
  1805 algebras, using new overloaded constants scaleR :: real => 'a => 'a
  1806 and norm :: 'a => real.
  1807 
  1808 * Real: constant of_real :: real => 'a::real_algebra_1 injects from
  1809 reals into other types. The overloaded constant Reals :: 'a set is now
  1810 defined as range of_real; potential INCOMPATIBILITY.
  1811 
  1812 * Real: proper support for ML code generation, including 'quickcheck'.
  1813 Reals are implemented as arbitrary precision rationals.
  1814 
  1815 * Hyperreal: Several constants that previously worked only for the
  1816 reals have been generalized, so they now work over arbitrary vector
  1817 spaces. Type annotations may need to be added in some cases; potential
  1818 INCOMPATIBILITY.
  1819 
  1820   Infinitesimal  :: ('a::real_normed_vector) star set
  1821   HFinite        :: ('a::real_normed_vector) star set
  1822   HInfinite      :: ('a::real_normed_vector) star set
  1823   approx         :: ('a::real_normed_vector) star => 'a star => bool
  1824   monad          :: ('a::real_normed_vector) star => 'a star set
  1825   galaxy         :: ('a::real_normed_vector) star => 'a star set
  1826   (NS)LIMSEQ     :: [nat => 'a::real_normed_vector, 'a] => bool
  1827   (NS)convergent :: (nat => 'a::real_normed_vector) => bool
  1828   (NS)Bseq       :: (nat => 'a::real_normed_vector) => bool
  1829   (NS)Cauchy     :: (nat => 'a::real_normed_vector) => bool
  1830   (NS)LIM        :: ['a::real_normed_vector => 'b::real_normed_vector, 'a, 'b] => bool
  1831   is(NS)Cont     :: ['a::real_normed_vector => 'b::real_normed_vector, 'a] => bool
  1832   deriv          :: ['a::real_normed_field => 'a, 'a, 'a] => bool
  1833   sgn            :: 'a::real_normed_vector => 'a
  1834   exp            :: 'a::{recpower,real_normed_field,banach} => 'a
  1835 
  1836 * Complex: Some complex-specific constants are now abbreviations for
  1837 overloaded ones: complex_of_real = of_real, cmod = norm, hcmod =
  1838 hnorm.  Other constants have been entirely removed in favor of the
  1839 polymorphic versions (INCOMPATIBILITY):
  1840 
  1841   approx        <-- capprox
  1842   HFinite       <-- CFinite
  1843   HInfinite     <-- CInfinite
  1844   Infinitesimal <-- CInfinitesimal
  1845   monad         <-- cmonad
  1846   galaxy        <-- cgalaxy
  1847   (NS)LIM       <-- (NS)CLIM, (NS)CRLIM
  1848   is(NS)Cont    <-- is(NS)Contc, is(NS)contCR
  1849   (ns)deriv     <-- (ns)cderiv
  1850 
  1851 
  1852 *** HOL-Algebra ***
  1853 
  1854 * Formalisation of ideals and the quotient construction over rings.
  1855 
  1856 * Order and lattice theory no longer based on records.
  1857 INCOMPATIBILITY.
  1858 
  1859 * Renamed lemmas least_carrier -> least_closed and greatest_carrier ->
  1860 greatest_closed.  INCOMPATIBILITY.
  1861 
  1862 * Method algebra is now set up via an attribute.  For examples see
  1863 Ring.thy.  INCOMPATIBILITY: the method is now weaker on combinations
  1864 of algebraic structures.
  1865 
  1866 * Renamed theory CRing to Ring.
  1867 
  1868 
  1869 *** HOL-Nominal ***
  1870 
  1871 * Substantial, yet incomplete support for nominal datatypes (binding
  1872 structures) based on HOL-Nominal logic.  See src/HOL/Nominal and
  1873 src/HOL/Nominal/Examples.  Prospective users should consult
  1874 http://isabelle.in.tum.de/nominal/
  1875 
  1876 
  1877 *** ML ***
  1878 
  1879 * ML basics: just one true type int, which coincides with IntInf.int
  1880 (even on SML/NJ).
  1881 
  1882 * ML within Isar: antiquotations allow to embed statically-checked
  1883 formal entities in the source, referring to the context available at
  1884 compile-time.  For example:
  1885 
  1886 ML {* @{sort "{zero,one}"} *}
  1887 ML {* @{typ "'a => 'b"} *}
  1888 ML {* @{term "%x. x"} *}
  1889 ML {* @{prop "x == y"} *}
  1890 ML {* @{ctyp "'a => 'b"} *}
  1891 ML {* @{cterm "%x. x"} *}
  1892 ML {* @{cprop "x == y"} *}
  1893 ML {* @{thm asm_rl} *}
  1894 ML {* @{thms asm_rl} *}
  1895 ML {* @{type_name c} *}
  1896 ML {* @{type_syntax c} *}
  1897 ML {* @{const_name c} *}
  1898 ML {* @{const_syntax c} *}
  1899 ML {* @{context} *}
  1900 ML {* @{theory} *}
  1901 ML {* @{theory Pure} *}
  1902 ML {* @{theory_ref} *}
  1903 ML {* @{theory_ref Pure} *}
  1904 ML {* @{simpset} *}
  1905 ML {* @{claset} *}
  1906 ML {* @{clasimpset} *}
  1907 
  1908 The same works for sources being ``used'' within an Isar context.
  1909 
  1910 * ML in Isar: improved error reporting; extra verbosity with
  1911 ML_Context.trace enabled.
  1912 
  1913 * Pure/General/table.ML: the join operations now works via exceptions
  1914 DUP/SAME instead of type option. This is simpler in simple cases, and
  1915 admits slightly more efficient complex applications.
  1916 
  1917 * Pure: 'advanced' translation functions (parse_translation etc.) now
  1918 use Context.generic instead of just theory.
  1919 
  1920 * Pure: datatype Context.generic joins theory/Proof.context and
  1921 provides some facilities for code that works in either kind of
  1922 context, notably GenericDataFun for uniform theory and proof data.
  1923 
  1924 * Pure: simplified internal attribute type, which is now always
  1925 Context.generic * thm -> Context.generic * thm. Global (theory) vs.
  1926 local (Proof.context) attributes have been discontinued, while
  1927 minimizing code duplication. Thm.rule_attribute and
  1928 Thm.declaration_attribute build canonical attributes; see also structure
  1929 Context for further operations on Context.generic, notably
  1930 GenericDataFun. INCOMPATIBILITY, need to adapt attribute type
  1931 declarations and definitions.
  1932 
  1933 * Context data interfaces (Theory/Proof/GenericDataFun): removed
  1934 name/print, uninitialized data defaults to ad-hoc copy of empty value,
  1935 init only required for impure data. INCOMPATIBILITY: empty really need
  1936 to be empty (no dependencies on theory content!)
  1937 
  1938 * Pure/kernel: consts certification ignores sort constraints given in
  1939 signature declarations. (This information is not relevant to the
  1940 logic, but only for type inference.) SIGNIFICANT INTERNAL CHANGE,
  1941 potential INCOMPATIBILITY.
  1942 
  1943 * Pure: axiomatic type classes are now purely definitional, with
  1944 explicit proofs of class axioms and super class relations performed
  1945 internally. See Pure/axclass.ML for the main internal interfaces --
  1946 notably AxClass.define_class supercedes AxClass.add_axclass, and
  1947 AxClass.axiomatize_class/classrel/arity supersede
  1948 Sign.add_classes/classrel/arities.
  1949 
  1950 * Pure/Isar: Args/Attrib parsers operate on Context.generic --
  1951 global/local versions on theory vs. Proof.context have been
  1952 discontinued; Attrib.syntax and Method.syntax have been adapted
  1953 accordingly.  INCOMPATIBILITY, need to adapt parser expressions for
  1954 attributes, methods, etc.
  1955 
  1956 * Pure: several functions of signature "... -> theory -> theory * ..."
  1957 have been reoriented to "... -> theory -> ... * theory" in order to
  1958 allow natural usage in combination with the ||>, ||>>, |-> and
  1959 fold_map combinators.
  1960 
  1961 * Pure: official theorem names (closed derivations) and additional
  1962 comments (tags) are now strictly separate.  Name hints -- which are
  1963 maintained as tags -- may be attached any time without affecting the
  1964 derivation.
  1965 
  1966 * Pure: primitive rule lift_rule now takes goal cterm instead of an
  1967 actual goal state (thm).  Use Thm.lift_rule (Thm.cprem_of st i) to
  1968 achieve the old behaviour.
  1969 
  1970 * Pure: the "Goal" constant is now called "prop", supporting a
  1971 slightly more general idea of ``protecting'' meta-level rule
  1972 statements.
  1973 
  1974 * Pure: Logic.(un)varify only works in a global context, which is now
  1975 enforced instead of silently assumed.  INCOMPATIBILITY, may use
  1976 Logic.legacy_(un)varify as temporary workaround.
  1977 
  1978 * Pure: structure Name provides scalable operations for generating
  1979 internal variable names, notably Name.variants etc.  This replaces
  1980 some popular functions from term.ML:
  1981 
  1982   Term.variant		->  Name.variant
  1983   Term.variantlist	->  Name.variant_list
  1984   Term.invent_names	->  Name.invent_list
  1985 
  1986 Note that low-level renaming rarely occurs in new code -- operations
  1987 from structure Variable are used instead (see below).
  1988 
  1989 * Pure: structure Variable provides fundamental operations for proper
  1990 treatment of fixed/schematic variables in a context.  For example,
  1991 Variable.import introduces fixes for schematics of given facts and
  1992 Variable.export reverses the effect (up to renaming) -- this replaces
  1993 various freeze_thaw operations.
  1994 
  1995 * Pure: structure Goal provides simple interfaces for
  1996 init/conclude/finish and tactical prove operations (replacing former
  1997 Tactic.prove).  Goal.prove is the canonical way to prove results
  1998 within a given context; Goal.prove_global is a degraded version for
  1999 theory level goals, including a global Drule.standard.  Note that
  2000 OldGoals.prove_goalw_cterm has long been obsolete, since it is
  2001 ill-behaved in a local proof context (e.g. with local fixes/assumes or
  2002 in a locale context).
  2003 
  2004 * Pure/Syntax: generic interfaces for parsing (Syntax.parse_term etc.)
  2005 and type checking (Syntax.check_term etc.), with common combinations
  2006 (Syntax.read_term etc.). These supersede former Sign.read_term etc.
  2007 which are considered legacy and await removal.
  2008 
  2009 * Pure/Syntax: generic interfaces for type unchecking
  2010 (Syntax.uncheck_terms etc.) and unparsing (Syntax.unparse_term etc.),
  2011 with common combinations (Syntax.pretty_term, Syntax.string_of_term
  2012 etc.).  Former Sign.pretty_term, Sign.string_of_term etc. are still
  2013 available for convenience, but refer to the very same operations using
  2014 a mere theory instead of a full context.
  2015 
  2016 * Isar: simplified treatment of user-level errors, using exception
  2017 ERROR of string uniformly.  Function error now merely raises ERROR,
  2018 without any side effect on output channels.  The Isar toplevel takes
  2019 care of proper display of ERROR exceptions.  ML code may use plain
  2020 handle/can/try; cat_error may be used to concatenate errors like this:
  2021 
  2022   ... handle ERROR msg => cat_error msg "..."
  2023 
  2024 Toplevel ML code (run directly or through the Isar toplevel) may be
  2025 embedded into the Isar toplevel with exception display/debug like
  2026 this:
  2027 
  2028   Isar.toplevel (fn () => ...)
  2029 
  2030 INCOMPATIBILITY, removed special transform_error facilities, removed
  2031 obsolete variants of user-level exceptions (ERROR_MESSAGE,
  2032 Context.PROOF, ProofContext.CONTEXT, Proof.STATE, ProofHistory.FAIL)
  2033 -- use plain ERROR instead.
  2034 
  2035 * Isar: theory setup now has type (theory -> theory), instead of a
  2036 list.  INCOMPATIBILITY, may use #> to compose setup functions.
  2037 
  2038 * Isar: ML toplevel pretty printer for type Proof.context, subject to
  2039 ProofContext.debug/verbose flags.
  2040 
  2041 * Isar: Toplevel.theory_to_proof admits transactions that modify the
  2042 theory before entering a proof state.  Transactions now always see a
  2043 quasi-functional intermediate checkpoint, both in interactive and
  2044 batch mode.
  2045 
  2046 * Isar: simplified interfaces for outer syntax.  Renamed
  2047 OuterSyntax.add_keywords to OuterSyntax.keywords.  Removed
  2048 OuterSyntax.add_parsers -- this functionality is now included in
  2049 OuterSyntax.command etc.  INCOMPATIBILITY.
  2050 
  2051 * Simplifier: the simpset of a running simplification process now
  2052 contains a proof context (cf. Simplifier.the_context), which is the
  2053 very context that the initial simpset has been retrieved from (by
  2054 simpset_of/local_simpset_of).  Consequently, all plug-in components
  2055 (solver, looper etc.) may depend on arbitrary proof data.
  2056 
  2057 * Simplifier.inherit_context inherits the proof context (plus the
  2058 local bounds) of the current simplification process; any simproc
  2059 etc. that calls the Simplifier recursively should do this!  Removed
  2060 former Simplifier.inherit_bounds, which is already included here --
  2061 INCOMPATIBILITY.  Tools based on low-level rewriting may even have to
  2062 specify an explicit context using Simplifier.context/theory_context.
  2063 
  2064 * Simplifier/Classical Reasoner: more abstract interfaces
  2065 change_simpset/claset for modifying the simpset/claset reference of a
  2066 theory; raw versions simpset/claset_ref etc. have been discontinued --
  2067 INCOMPATIBILITY.
  2068 
  2069 * Provers: more generic wrt. syntax of object-logics, avoid hardwired
  2070 "Trueprop" etc.
  2071 
  2072 
  2073 *** System ***
  2074 
  2075 * settings: the default heap location within ISABELLE_HOME_USER now
  2076 includes ISABELLE_IDENTIFIER.  This simplifies use of multiple
  2077 Isabelle installations.
  2078 
  2079 * isabelle-process: option -S (secure mode) disables some critical
  2080 operations, notably runtime compilation and evaluation of ML source
  2081 code.
  2082 
  2083 * Basic Isabelle mode for jEdit, see Isabelle/lib/jedit/.
  2084 
  2085 * Support for parallel execution, using native multicore support of
  2086 Poly/ML 5.1.  The theory loader exploits parallelism when processing
  2087 independent theories, according to the given theory header
  2088 specifications. The maximum number of worker threads is specified via
  2089 usedir option -M or the "max-threads" setting in Proof General. A
  2090 speedup factor of 1.5--3.5 can be expected on a 4-core machine, and up
  2091 to 6 on a 8-core machine.  User-code needs to observe certain
  2092 guidelines for thread-safe programming, see appendix A in the Isar
  2093 Implementation manual.
  2094 
  2095 
  2096 
  2097 New in Isabelle2005 (October 2005)
  2098 ----------------------------------
  2099 
  2100 *** General ***
  2101 
  2102 * Theory headers: the new header syntax for Isar theories is
  2103 
  2104   theory <name>
  2105   imports <theory1> ... <theoryN>
  2106   uses <file1> ... <fileM>
  2107   begin
  2108 
  2109 where the 'uses' part is optional.  The previous syntax
  2110 
  2111   theory <name> = <theory1> + ... + <theoryN>:
  2112 
  2113 will disappear in the next release.  Use isatool fixheaders to convert
  2114 existing theory files.  Note that there is no change in ancient
  2115 non-Isar theories now, but these will disappear soon.
  2116 
  2117 * Theory loader: parent theories can now also be referred to via
  2118 relative and absolute paths.
  2119 
  2120 * Command 'find_theorems' searches for a list of criteria instead of a
  2121 list of constants. Known criteria are: intro, elim, dest, name:string,
  2122 simp:term, and any term. Criteria can be preceded by '-' to select
  2123 theorems that do not match. Intro, elim, dest select theorems that
  2124 match the current goal, name:s selects theorems whose fully qualified
  2125 name contain s, and simp:term selects all simplification rules whose
  2126 lhs match term.  Any other term is interpreted as pattern and selects
  2127 all theorems matching the pattern. Available in ProofGeneral under
  2128 'ProofGeneral -> Find Theorems' or C-c C-f.  Example:
  2129 
  2130   C-c C-f (100) "(_::nat) + _ + _" intro -name: "HOL."
  2131 
  2132 prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
  2133 matching the current goal as introduction rule and not having "HOL."
  2134 in their name (i.e. not being defined in theory HOL).
  2135 
  2136 * Command 'thms_containing' has been discontinued in favour of
  2137 'find_theorems'; INCOMPATIBILITY.
  2138 
  2139 * Communication with Proof General is now 8bit clean, which means that
  2140 Unicode text in UTF-8 encoding may be used within theory texts (both
  2141 formal and informal parts).  Cf. option -U of the Isabelle Proof
  2142 General interface.  Here are some simple examples (cf. src/HOL/ex):
  2143 
  2144   http://isabelle.in.tum.de/library/HOL/ex/Hebrew.html
  2145   http://isabelle.in.tum.de/library/HOL/ex/Chinese.html
  2146 
  2147 * Improved efficiency of the Simplifier and, to a lesser degree, the
  2148 Classical Reasoner.  Typical big applications run around 2 times
  2149 faster.
  2150 
  2151 
  2152 *** Document preparation ***
  2153 
  2154 * Commands 'display_drafts' and 'print_drafts' perform simple output
  2155 of raw sources.  Only those symbols that do not require additional
  2156 LaTeX packages (depending on comments in isabellesym.sty) are
  2157 displayed properly, everything else is left verbatim.  isatool display
  2158 and isatool print are used as front ends (these are subject to the
  2159 DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively).
  2160 
  2161 * Command tags control specific markup of certain regions of text,
  2162 notably folding and hiding.  Predefined tags include "theory" (for
  2163 theory begin and end), "proof" for proof commands, and "ML" for
  2164 commands involving ML code; the additional tags "visible" and
  2165 "invisible" are unused by default.  Users may give explicit tag
  2166 specifications in the text, e.g. ''by %invisible (auto)''.  The
  2167 interpretation of tags is determined by the LaTeX job during document
  2168 preparation: see option -V of isatool usedir, or options -n and -t of
  2169 isatool document, or even the LaTeX macros \isakeeptag, \isafoldtag,
  2170 \isadroptag.
  2171 
  2172 Several document versions may be produced at the same time via isatool
  2173 usedir (the generated index.html will link all of them).  Typical
  2174 specifications include ''-V document=theory,proof,ML'' to present
  2175 theory/proof/ML parts faithfully, ''-V outline=/proof,/ML'' to fold
  2176 proof and ML commands, and ''-V mutilated=-theory,-proof,-ML'' to omit
  2177 these parts without any formal replacement text.  The Isabelle site
  2178 default settings produce ''document'' and ''outline'' versions as
  2179 specified above.
  2180 
  2181 * Several new antiquotations:
  2182 
  2183   @{term_type term} prints a term with its type annotated;
  2184 
  2185   @{typeof term} prints the type of a term;
  2186 
  2187   @{const const} is the same as @{term const}, but checks that the
  2188   argument is a known logical constant;
  2189 
  2190   @{term_style style term} and @{thm_style style thm} print a term or
  2191   theorem applying a "style" to it
  2192 
  2193   @{ML text}
  2194 
  2195 Predefined styles are 'lhs' and 'rhs' printing the lhs/rhs of
  2196 definitions, equations, inequations etc., 'concl' printing only the
  2197 conclusion of a meta-logical statement theorem, and 'prem1' .. 'prem19'
  2198 to print the specified premise.  TermStyle.add_style provides an ML
  2199 interface for introducing further styles.  See also the "LaTeX Sugar"
  2200 document practical applications.  The ML antiquotation prints
  2201 type-checked ML expressions verbatim.
  2202 
  2203 * Markup commands 'chapter', 'section', 'subsection', 'subsubsection',
  2204 and 'text' support optional locale specification '(in loc)', which
  2205 specifies the default context for interpreting antiquotations.  For
  2206 example: 'text (in lattice) {* @{thm inf_assoc}*}'.
  2207 
  2208 * Option 'locale=NAME' of antiquotations specifies an alternative
  2209 context interpreting the subsequent argument.  For example: @{thm
  2210 [locale=lattice] inf_assoc}.
  2211 
  2212 * Proper output of proof terms (@{prf ...} and @{full_prf ...}) within
  2213 a proof context.
  2214 
  2215 * Proper output of antiquotations for theory commands involving a
  2216 proof context (such as 'locale' or 'theorem (in loc) ...').
  2217 
  2218 * Delimiters of outer tokens (string etc.) now produce separate LaTeX
  2219 macros (\isachardoublequoteopen, isachardoublequoteclose etc.).
  2220 
  2221 * isatool usedir: new option -C (default true) controls whether option
  2222 -D should include a copy of the original document directory; -C false
  2223 prevents unwanted effects such as copying of administrative CVS data.
  2224 
  2225 
  2226 *** Pure ***
  2227 
  2228 * Considerably improved version of 'constdefs' command.  Now performs
  2229 automatic type-inference of declared constants; additional support for
  2230 local structure declarations (cf. locales and HOL records), see also
  2231 isar-ref manual.  Potential INCOMPATIBILITY: need to observe strictly
  2232 sequential dependencies of definitions within a single 'constdefs'
  2233 section; moreover, the declared name needs to be an identifier.  If
  2234 all fails, consider to fall back on 'consts' and 'defs' separately.
  2235 
  2236 * Improved indexed syntax and implicit structures.  First of all,
  2237 indexed syntax provides a notational device for subscripted
  2238 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
  2239 expressions.  Secondly, in a local context with structure
  2240 declarations, number indexes \<^sub>n or the empty index (default
  2241 number 1) refer to a certain fixed variable implicitly; option
  2242 show_structs controls printing of implicit structures.  Typical
  2243 applications of these concepts involve record types and locales.
  2244 
  2245 * New command 'no_syntax' removes grammar declarations (and
  2246 translations) resulting from the given syntax specification, which is
  2247 interpreted in the same manner as for the 'syntax' command.
  2248 
  2249 * 'Advanced' translation functions (parse_translation etc.) may depend
  2250 on the signature of the theory context being presently used for
  2251 parsing/printing, see also isar-ref manual.
  2252 
  2253 * Improved 'oracle' command provides a type-safe interface to turn an
  2254 ML expression of type theory -> T -> term into a primitive rule of
  2255 type theory -> T -> thm (i.e. the functionality of Thm.invoke_oracle
  2256 is already included here); see also FOL/ex/IffExample.thy;
  2257 INCOMPATIBILITY.
  2258 
  2259 * axclass: name space prefix for class "c" is now "c_class" (was "c"
  2260 before); "cI" is no longer bound, use "c.intro" instead.
  2261 INCOMPATIBILITY.  This change avoids clashes of fact bindings for
  2262 axclasses vs. locales.
  2263 
  2264 * Improved internal renaming of symbolic identifiers -- attach primes
  2265 instead of base 26 numbers.
  2266 
  2267 * New flag show_question_marks controls printing of leading question
  2268 marks in schematic variable names.
  2269 
  2270 * In schematic variable names, *any* symbol following \<^isub> or
  2271 \<^isup> is now treated as part of the base name.  For example, the
  2272 following works without printing of awkward ".0" indexes:
  2273 
  2274   lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
  2275     by simp
  2276 
  2277 * Inner syntax includes (*(*nested*) comments*).
  2278 
  2279 * Pretty printer now supports unbreakable blocks, specified in mixfix
  2280 annotations as "(00...)".
  2281 
  2282 * Clear separation of logical types and nonterminals, where the latter
  2283 may only occur in 'syntax' specifications or type abbreviations.
  2284 Before that distinction was only partially implemented via type class
  2285 "logic" vs. "{}".  Potential INCOMPATIBILITY in rare cases of improper
  2286 use of 'types'/'consts' instead of 'nonterminals'/'syntax'.  Some very
  2287 exotic syntax specifications may require further adaption
  2288 (e.g. Cube/Cube.thy).
  2289 
  2290 * Removed obsolete type class "logic", use the top sort {} instead.
  2291 Note that non-logical types should be declared as 'nonterminals'
  2292 rather than 'types'.  INCOMPATIBILITY for new object-logic
  2293 specifications.
  2294 
  2295 * Attributes 'induct' and 'cases': type or set names may now be
  2296 locally fixed variables as well.
  2297 
  2298 * Simplifier: can now control the depth to which conditional rewriting
  2299 is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth
  2300 Limit.
  2301 
  2302 * Simplifier: simplification procedures may now take the current
  2303 simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
  2304 interface), which is very useful for calling the Simplifier
  2305 recursively.  Minor INCOMPATIBILITY: the 'prems' argument of simprocs
  2306 is gone -- use prems_of_ss on the simpset instead.  Moreover, the
  2307 low-level mk_simproc no longer applies Logic.varify internally, to
  2308 allow for use in a context of fixed variables.
  2309 
  2310 * thin_tac now works even if the assumption being deleted contains !!
  2311 or ==>.  More generally, erule now works even if the major premise of
  2312 the elimination rule contains !! or ==>.
  2313 
  2314 * Method 'rules' has been renamed to 'iprover'. INCOMPATIBILITY.
  2315 
  2316 * Reorganized bootstrapping of the Pure theories; CPure is now derived
  2317 from Pure, which contains all common declarations already.  Both
  2318 theories are defined via plain Isabelle/Isar .thy files.
  2319 INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
  2320 CPure.elim / CPure.dest attributes) now appear in the Pure name space;
  2321 use isatool fixcpure to adapt your theory and ML sources.
  2322 
  2323 * New syntax 'name(i-j, i-, i, ...)' for referring to specific
  2324 selections of theorems in named facts via index ranges.
  2325 
  2326 * 'print_theorems': in theory mode, really print the difference
  2327 wrt. the last state (works for interactive theory development only),
  2328 in proof mode print all local facts (cf. 'print_facts');
  2329 
  2330 * 'hide': option '(open)' hides only base names.
  2331 
  2332 * More efficient treatment of intermediate checkpoints in interactive
  2333 theory development.
  2334 
  2335 * Code generator is now invoked via code_module (incremental code
  2336 generation) and code_library (modular code generation, ML structures
  2337 for each theory).  INCOMPATIBILITY: new keywords 'file' and 'contains'
  2338 must be quoted when used as identifiers.
  2339 
  2340 * New 'value' command for reading, evaluating and printing terms using
  2341 the code generator.  INCOMPATIBILITY: command keyword 'value' must be
  2342 quoted when used as identifier.
  2343 
  2344 
  2345 *** Locales ***
  2346 
  2347 * New commands for the interpretation of locale expressions in
  2348 theories (1), locales (2) and proof contexts (3).  These generate
  2349 proof obligations from the expression specification.  After the
  2350 obligations have been discharged, theorems of the expression are added
  2351 to the theory, target locale or proof context.  The synopsis of the
  2352 commands is a follows:
  2353 
  2354   (1) interpretation expr inst
  2355   (2) interpretation target < expr
  2356   (3) interpret expr inst
  2357 
  2358 Interpretation in theories and proof contexts require a parameter
  2359 instantiation of terms from the current context.  This is applied to
  2360 specifications and theorems of the interpreted expression.
  2361 Interpretation in locales only permits parameter renaming through the
  2362 locale expression.  Interpretation is smart in that interpretations
  2363 that are active already do not occur in proof obligations, neither are
  2364 instantiated theorems stored in duplicate.  Use 'print_interps' to
  2365 inspect active interpretations of a particular locale.  For details,
  2366 see the Isar Reference manual.  Examples can be found in
  2367 HOL/Finite_Set.thy and HOL/Algebra/UnivPoly.thy.
  2368 
  2369 INCOMPATIBILITY: former 'instantiate' has been withdrawn, use
  2370 'interpret' instead.
  2371 
  2372 * New context element 'constrains' for adding type constraints to
  2373 parameters.
  2374 
  2375 * Context expressions: renaming of parameters with syntax
  2376 redeclaration.
  2377 
  2378 * Locale declaration: 'includes' disallowed.
  2379 
  2380 * Proper static binding of attribute syntax -- i.e. types / terms /
  2381 facts mentioned as arguments are always those of the locale definition
  2382 context, independently of the context of later invocations.  Moreover,
  2383 locale operations (renaming and type / term instantiation) are applied
  2384 to attribute arguments as expected.
  2385 
  2386 INCOMPATIBILITY of the ML interface: always pass Attrib.src instead of
  2387 actual attributes; rare situations may require Attrib.attribute to
  2388 embed those attributes into Attrib.src that lack concrete syntax.
  2389 Attribute implementations need to cooperate properly with the static
  2390 binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
  2391 Attrib.XXX_thm etc. already do the right thing without further
  2392 intervention.  Only unusual applications -- such as "where" or "of"
  2393 (cf. src/Pure/Isar/attrib.ML), which process arguments depending both
  2394 on the context and the facts involved -- may have to assign parsed
  2395 values to argument tokens explicitly.
  2396 
  2397 * Changed parameter management in theorem generation for long goal
  2398 statements with 'includes'.  INCOMPATIBILITY: produces a different
  2399 theorem statement in rare situations.
  2400 
  2401 * Locale inspection command 'print_locale' omits notes elements.  Use
  2402 'print_locale!' to have them included in the output.
  2403 
  2404 
  2405 *** Provers ***
  2406 
  2407 * Provers/hypsubst.ML: improved version of the subst method, for
  2408 single-step rewriting: it now works in bound variable contexts. New is
  2409 'subst (asm)', for rewriting an assumption.  INCOMPATIBILITY: may
  2410 rewrite a different subterm than the original subst method, which is
  2411 still available as 'simplesubst'.
  2412 
  2413 * Provers/quasi.ML: new transitivity reasoners for transitivity only
  2414 and quasi orders.
  2415 
  2416 * Provers/trancl.ML: new transitivity reasoner for transitive and
  2417 reflexive-transitive closure of relations.
  2418 
  2419 * Provers/blast.ML: new reference depth_limit to make blast's depth
  2420 limit (previously hard-coded with a value of 20) user-definable.
  2421 
  2422 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
  2423 is peformed already.  Object-logics merely need to finish their
  2424 initial simpset configuration as before.  INCOMPATIBILITY.
  2425 
  2426 
  2427 *** HOL ***
  2428 
  2429 * Symbolic syntax of Hilbert Choice Operator is now as follows:
  2430 
  2431   syntax (epsilon)
  2432     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
  2433 
  2434 The symbol \<some> is displayed as the alternative epsilon of LaTeX
  2435 and x-symbol; use option '-m epsilon' to get it actually printed.
  2436 Moreover, the mathematically important symbolic identifier \<epsilon>
  2437 becomes available as variable, constant etc.  INCOMPATIBILITY,
  2438 
  2439 * "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
  2440 Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
  2441 is \<ge>. New transitivity rules have been added to HOL/Orderings.thy to
  2442 support corresponding Isar calculations.
  2443 
  2444 * "{x:A. P}" abbreviates "{x. x:A & P}", and similarly for "\<in>"
  2445 instead of ":".
  2446 
  2447 * theory SetInterval: changed the syntax for open intervals:
  2448 
  2449   Old       New
  2450   {..n(}    {..<n}
  2451   {)n..}    {n<..}
  2452   {m..n(}   {m..<n}
  2453   {)m..n}   {m<..n}
  2454   {)m..n(}  {m<..<n}
  2455 
  2456 The old syntax is still supported but will disappear in the next
  2457 release.  For conversion use the following Emacs search and replace
  2458 patterns (these are not perfect but work quite well):
  2459 
  2460   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
  2461   \.\.\([^(}]*\)(}  ->  \.\.<\1}
  2462 
  2463 * Theory Commutative_Ring (in Library): method comm_ring for proving
  2464 equalities in commutative rings; method 'algebra' provides a generic
  2465 interface.
  2466 
  2467 * Theory Finite_Set: changed the syntax for 'setsum', summation over
  2468 finite sets: "setsum (%x. e) A", which used to be "\<Sum>x:A. e", is
  2469 now either "SUM x:A. e" or "\<Sum>x \<in> A. e". The bound variable can
  2470 be a tuple pattern.
  2471 
  2472 Some new syntax forms are available:
  2473 
  2474   "\<Sum>x | P. e"      for     "setsum (%x. e) {x. P}"
  2475   "\<Sum>x = a..b. e"   for     "setsum (%x. e) {a..b}"
  2476   "\<Sum>x = a..<b. e"  for     "setsum (%x. e) {a..<b}"
  2477   "\<Sum>x < k. e"      for     "setsum (%x. e) {..<k}"
  2478 
  2479 The latter form "\<Sum>x < k. e" used to be based on a separate
  2480 function "Summation", which has been discontinued.
  2481 
  2482 * theory Finite_Set: in structured induction proofs, the insert case
  2483 is now 'case (insert x F)' instead of the old counterintuitive 'case
  2484 (insert F x)'.
  2485 
  2486 * The 'refute' command has been extended to support a much larger
  2487 fragment of HOL, including axiomatic type classes, constdefs and
  2488 typedefs, inductive datatypes and recursion.
  2489 
  2490 * New tactics 'sat' and 'satx' to prove propositional tautologies.
  2491 Requires zChaff with proof generation to be installed.  See
  2492 HOL/ex/SAT_Examples.thy for examples.
  2493 
  2494 * Datatype induction via method 'induct' now preserves the name of the
  2495 induction variable. For example, when proving P(xs::'a list) by
  2496 induction on xs, the induction step is now P(xs) ==> P(a#xs) rather
  2497 than P(list) ==> P(a#list) as previously.  Potential INCOMPATIBILITY
  2498 in unstructured proof scripts.
  2499 
  2500 * Reworked implementation of records.  Improved scalability for
  2501 records with many fields, avoiding performance problems for type
  2502 inference. Records are no longer composed of nested field types, but
  2503 of nested extension types. Therefore the record type only grows linear
  2504 in the number of extensions and not in the number of fields.  The
  2505 top-level (users) view on records is preserved.  Potential
  2506 INCOMPATIBILITY only in strange cases, where the theory depends on the
  2507 old record representation. The type generated for a record is called
  2508 <record_name>_ext_type.
  2509 
  2510 Flag record_quick_and_dirty_sensitive can be enabled to skip the
  2511 proofs triggered by a record definition or a simproc (if
  2512 quick_and_dirty is enabled).  Definitions of large records can take
  2513 quite long.
  2514 
  2515 New simproc record_upd_simproc for simplification of multiple record
  2516 updates enabled by default.  Moreover, trivial updates are also
  2517 removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
  2518 occasionally, since simplification is more powerful by default.
  2519 
  2520 * typedef: proper support for polymorphic sets, which contain extra
  2521 type-variables in the term.
  2522 
  2523 * Simplifier: automatically reasons about transitivity chains
  2524 involving "trancl" (r^+) and "rtrancl" (r^*) by setting up tactics
  2525 provided by Provers/trancl.ML as additional solvers.  INCOMPATIBILITY:
  2526 old proofs break occasionally as simplification may now solve more
  2527 goals than previously.
  2528 
  2529 * Simplifier: converts x <= y into x = y if assumption y <= x is
  2530 present.  Works for all partial orders (class "order"), in particular
  2531 numbers and sets.  For linear orders (e.g. numbers) it treats ~ x < y
  2532 just like y <= x.
  2533 
  2534 * Simplifier: new simproc for "let x = a in f x".  If a is a free or
  2535 bound variable or a constant then the let is unfolded.  Otherwise
  2536 first a is simplified to b, and then f b is simplified to g. If
  2537 possible we abstract b from g arriving at "let x = b in h x",
  2538 otherwise we unfold the let and arrive at g.  The simproc can be
  2539 enabled/disabled by the reference use_let_simproc.  Potential
  2540 INCOMPATIBILITY since simplification is more powerful by default.
  2541 
  2542 * Classical reasoning: the meson method now accepts theorems as arguments.
  2543 
  2544 * Prover support: pre-release of the Isabelle-ATP linkup, which runs background
  2545 jobs to provide advice on the provability of subgoals.
  2546 
  2547 * Theory OrderedGroup and Ring_and_Field: various additions and
  2548 improvements to faciliate calculations involving equalities and
  2549 inequalities.
  2550 
  2551 The following theorems have been eliminated or modified
  2552 (INCOMPATIBILITY):
  2553 
  2554   abs_eq             now named abs_of_nonneg
  2555   abs_of_ge_0        now named abs_of_nonneg
  2556   abs_minus_eq       now named abs_of_nonpos
  2557   imp_abs_id         now named abs_of_nonneg
  2558   imp_abs_neg_id     now named abs_of_nonpos
  2559   mult_pos           now named mult_pos_pos
  2560   mult_pos_le        now named mult_nonneg_nonneg
  2561   mult_pos_neg_le    now named mult_nonneg_nonpos
  2562   mult_pos_neg2_le   now named mult_nonneg_nonpos2
  2563   mult_neg           now named mult_neg_neg
  2564   mult_neg_le        now named mult_nonpos_nonpos
  2565 
  2566 * The following lemmas in Ring_and_Field have been added to the simplifier:
  2567      
  2568      zero_le_square
  2569      not_square_less_zero 
  2570 
  2571   The following lemmas have been deleted from Real/RealPow:
  2572   
  2573      realpow_zero_zero
  2574      realpow_two
  2575      realpow_less
  2576      zero_le_power
  2577      realpow_two_le
  2578      abs_realpow_two
  2579      realpow_two_abs     
  2580 
  2581 * Theory Parity: added rules for simplifying exponents.
  2582 
  2583 * Theory List:
  2584 
  2585 The following theorems have been eliminated or modified
  2586 (INCOMPATIBILITY):
  2587 
  2588   list_all_Nil       now named list_all.simps(1)
  2589   list_all_Cons      now named list_all.simps(2)
  2590   list_all_conv      now named list_all_iff
  2591   set_mem_eq         now named mem_iff
  2592 
  2593 * Theories SetsAndFunctions and BigO (see HOL/Library) support
  2594 asymptotic "big O" calculations.  See the notes in BigO.thy.
  2595 
  2596 
  2597 *** HOL-Complex ***
  2598 
  2599 * Theory RealDef: better support for embedding natural numbers and
  2600 integers in the reals.
  2601 
  2602 The following theorems have been eliminated or modified
  2603 (INCOMPATIBILITY):
  2604 
  2605   exp_ge_add_one_self  now requires no hypotheses
  2606   real_of_int_add      reversed direction of equality (use [symmetric])
  2607   real_of_int_minus    reversed direction of equality (use [symmetric])
  2608   real_of_int_diff     reversed direction of equality (use [symmetric])
  2609   real_of_int_mult     reversed direction of equality (use [symmetric])
  2610 
  2611 * Theory RComplete: expanded support for floor and ceiling functions.
  2612 
  2613 * Theory Ln is new, with properties of the natural logarithm
  2614 
  2615 * Hyperreal: There is a new type constructor "star" for making
  2616 nonstandard types.  The old type names are now type synonyms:
  2617 
  2618   hypreal = real star
  2619   hypnat = nat star
  2620   hcomplex = complex star
  2621 
  2622 * Hyperreal: Many groups of similarly-defined constants have been
  2623 replaced by polymorphic versions (INCOMPATIBILITY):
  2624 
  2625   star_of <-- hypreal_of_real, hypnat_of_nat, hcomplex_of_complex
  2626 
  2627   starset      <-- starsetNat, starsetC
  2628   *s*          <-- *sNat*, *sc*
  2629   starset_n    <-- starsetNat_n, starsetC_n
  2630   *sn*         <-- *sNatn*, *scn*
  2631   InternalSets <-- InternalNatSets, InternalCSets
  2632 
  2633   starfun      <-- starfun{Nat,Nat2,C,RC,CR}
  2634   *f*          <-- *fNat*, *fNat2*, *fc*, *fRc*, *fcR*
  2635   starfun_n    <-- starfun{Nat,Nat2,C,RC,CR}_n
  2636   *fn*         <-- *fNatn*, *fNat2n*, *fcn*, *fRcn*, *fcRn*
  2637   InternalFuns <-- InternalNatFuns, InternalNatFuns2, Internal{C,RC,CR}Funs
  2638 
  2639 * Hyperreal: Many type-specific theorems have been removed in favor of
  2640 theorems specific to various axiomatic type classes (INCOMPATIBILITY):
  2641 
  2642   add_commute <-- {hypreal,hypnat,hcomplex}_add_commute
  2643   add_assoc   <-- {hypreal,hypnat,hcomplex}_add_assocs
  2644   OrderedGroup.add_0 <-- {hypreal,hypnat,hcomplex}_add_zero_left
  2645   OrderedGroup.add_0_right <-- {hypreal,hcomplex}_add_zero_right
  2646   right_minus <-- hypreal_add_minus
  2647   left_minus <-- {hypreal,hcomplex}_add_minus_left
  2648   mult_commute <-- {hypreal,hypnat,hcomplex}_mult_commute
  2649   mult_assoc <-- {hypreal,hypnat,hcomplex}_mult_assoc
  2650   mult_1_left <-- {hypreal,hypnat}_mult_1, hcomplex_mult_one_left
  2651   mult_1_right <-- hcomplex_mult_one_right
  2652   mult_zero_left <-- hcomplex_mult_zero_left
  2653   left_distrib <-- {hypreal,hypnat,hcomplex}_add_mult_distrib
  2654   right_distrib <-- hypnat_add_mult_distrib2
  2655   zero_neq_one <-- {hypreal,hypnat,hcomplex}_zero_not_eq_one
  2656   right_inverse <-- hypreal_mult_inverse
  2657   left_inverse <-- hypreal_mult_inverse_left, hcomplex_mult_inv_left
  2658   order_refl <-- {hypreal,hypnat}_le_refl
  2659   order_trans <-- {hypreal,hypnat}_le_trans
  2660   order_antisym <-- {hypreal,hypnat}_le_anti_sym
  2661   order_less_le <-- {hypreal,hypnat}_less_le
  2662   linorder_linear <-- {hypreal,hypnat}_le_linear
  2663   add_left_mono <-- {hypreal,hypnat}_add_left_mono
  2664   mult_strict_left_mono <-- {hypreal,hypnat}_mult_less_mono2
  2665   add_nonneg_nonneg <-- hypreal_le_add_order
  2666 
  2667 * Hyperreal: Separate theorems having to do with type-specific
  2668 versions of constants have been merged into theorems that apply to the
  2669 new polymorphic constants (INCOMPATIBILITY):
  2670 
  2671   STAR_UNIV_set <-- {STAR_real,NatStar_real,STARC_complex}_set
  2672   STAR_empty_set <-- {STAR,NatStar,STARC}_empty_set
  2673   STAR_Un <-- {STAR,NatStar,STARC}_Un
  2674   STAR_Int <-- {STAR,NatStar,STARC}_Int
  2675   STAR_Compl <-- {STAR,NatStar,STARC}_Compl
  2676   STAR_subset <-- {STAR,NatStar,STARC}_subset
  2677   STAR_mem <-- {STAR,NatStar,STARC}_mem
  2678   STAR_mem_Compl <-- {STAR,STARC}_mem_Compl
  2679   STAR_diff <-- {STAR,STARC}_diff
  2680   STAR_star_of_image_subset <-- {STAR_hypreal_of_real, NatStar_hypreal_of_real,
  2681     STARC_hcomplex_of_complex}_image_subset
  2682   starset_n_Un <-- starset{Nat,C}_n_Un
  2683   starset_n_Int <-- starset{Nat,C}_n_Int
  2684   starset_n_Compl <-- starset{Nat,C}_n_Compl
  2685   starset_n_diff <-- starset{Nat,C}_n_diff
  2686   InternalSets_Un <-- Internal{Nat,C}Sets_Un
  2687   InternalSets_Int <-- Internal{Nat,C}Sets_Int
  2688   InternalSets_Compl <-- Internal{Nat,C}Sets_Compl
  2689   InternalSets_diff <-- Internal{Nat,C}Sets_diff
  2690   InternalSets_UNIV_diff <-- Internal{Nat,C}Sets_UNIV_diff
  2691   InternalSets_starset_n <-- Internal{Nat,C}Sets_starset{Nat,C}_n
  2692   starset_starset_n_eq <-- starset{Nat,C}_starset{Nat,C}_n_eq
  2693   starset_n_starset <-- starset{Nat,C}_n_starset{Nat,C}
  2694   starfun_n_starfun <-- starfun{Nat,Nat2,C,RC,CR}_n_starfun{Nat,Nat2,C,RC,CR}
  2695   starfun <-- starfun{Nat,Nat2,C,RC,CR}
  2696   starfun_mult <-- starfun{Nat,Nat2,C,RC,CR}_mult
  2697   starfun_add <-- starfun{Nat,Nat2,C,RC,CR}_add
  2698   starfun_minus <-- starfun{Nat,Nat2,C,RC,CR}_minus
  2699   starfun_diff <-- starfun{C,RC,CR}_diff
  2700   starfun_o <-- starfun{NatNat2,Nat2,_stafunNat,C,C_starfunRC,_starfunCR}_o
  2701   starfun_o2 <-- starfun{NatNat2,_stafunNat,C,C_starfunRC,_starfunCR}_o2
  2702   starfun_const_fun <-- starfun{Nat,Nat2,C,RC,CR}_const_fun
  2703   starfun_inverse <-- starfun{Nat,C,RC,CR}_inverse
  2704   starfun_eq <-- starfun{Nat,Nat2,C,RC,CR}_eq
  2705   starfun_eq_iff <-- starfun{C,RC,CR}_eq_iff
  2706   starfun_Id <-- starfunC_Id
  2707   starfun_approx <-- starfun{Nat,CR}_approx
  2708   starfun_capprox <-- starfun{C,RC}_capprox
  2709   starfun_abs <-- starfunNat_rabs
  2710   starfun_lambda_cancel <-- starfun{C,CR,RC}_lambda_cancel
  2711   starfun_lambda_cancel2 <-- starfun{C,CR,RC}_lambda_cancel2
  2712   starfun_mult_HFinite_approx <-- starfunCR_mult_HFinite_capprox
  2713   starfun_mult_CFinite_capprox <-- starfun{C,RC}_mult_CFinite_capprox
  2714   starfun_add_capprox <-- starfun{C,RC}_add_capprox
  2715   starfun_add_approx <-- starfunCR_add_approx
  2716   starfun_inverse_inverse <-- starfunC_inverse_inverse
  2717   starfun_divide <-- starfun{C,CR,RC}_divide
  2718   starfun_n <-- starfun{Nat,C}_n
  2719   starfun_n_mult <-- starfun{Nat,C}_n_mult
  2720   starfun_n_add <-- starfun{Nat,C}_n_add
  2721   starfun_n_add_minus <-- starfunNat_n_add_minus
  2722   starfun_n_const_fun <-- starfun{Nat,C}_n_const_fun
  2723   starfun_n_minus <-- starfun{Nat,C}_n_minus
  2724   starfun_n_eq <-- starfun{Nat,C}_n_eq
  2725 
  2726   star_n_add <-- {hypreal,hypnat,hcomplex}_add
  2727   star_n_minus <-- {hypreal,hcomplex}_minus
  2728   star_n_diff <-- {hypreal,hcomplex}_diff
  2729   star_n_mult <-- {hypreal,hcomplex}_mult
  2730   star_n_inverse <-- {hypreal,hcomplex}_inverse
  2731   star_n_le <-- {hypreal,hypnat}_le
  2732   star_n_less <-- {hypreal,hypnat}_less
  2733   star_n_zero_num <-- {hypreal,hypnat,hcomplex}_zero_num
  2734   star_n_one_num <-- {hypreal,hypnat,hcomplex}_one_num
  2735   star_n_abs <-- hypreal_hrabs
  2736   star_n_divide <-- hcomplex_divide
  2737 
  2738   star_of_add <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_add
  2739   star_of_minus <-- {hypreal_of_real,hcomplex_of_complex}_minus
  2740   star_of_diff <-- hypreal_of_real_diff
  2741   star_of_mult <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_mult
  2742   star_of_one <-- {hypreal_of_real,hcomplex_of_complex}_one
  2743   star_of_zero <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_zero
  2744   star_of_le <-- {hypreal_of_real,hypnat_of_nat}_le_iff
  2745   star_of_less <-- {hypreal_of_real,hypnat_of_nat}_less_iff
  2746   star_of_eq <-- {hypreal_of_real,hypnat_of_nat,hcomplex_of_complex}_eq_iff
  2747   star_of_inverse <-- {hypreal_of_real,hcomplex_of_complex}_inverse
  2748   star_of_divide <-- {hypreal_of_real,hcomplex_of_complex}_divide
  2749   star_of_of_nat <-- {hypreal_of_real,hcomplex_of_complex}_of_nat
  2750   star_of_of_int <-- {hypreal_of_real,hcomplex_of_complex}_of_int
  2751   star_of_number_of <-- {hypreal,hcomplex}_number_of
  2752   star_of_number_less <-- number_of_less_hypreal_of_real_iff
  2753   star_of_number_le <-- number_of_le_hypreal_of_real_iff
  2754   star_of_eq_number <-- hypreal_of_real_eq_number_of_iff
  2755   star_of_less_number <-- hypreal_of_real_less_number_of_iff
  2756   star_of_le_number <-- hypreal_of_real_le_number_of_iff
  2757   star_of_power <-- hypreal_of_real_power
  2758   star_of_eq_0 <-- hcomplex_of_complex_zero_iff
  2759 
  2760 * Hyperreal: new method "transfer" that implements the transfer
  2761 principle of nonstandard analysis. With a subgoal that mentions
  2762 nonstandard types like "'a star", the command "apply transfer"
  2763 replaces it with an equivalent one that mentions only standard types.
  2764 To be successful, all free variables must have standard types; non-
  2765 standard variables must have explicit universal quantifiers.
  2766 
  2767 * Hyperreal: A theory of Taylor series.
  2768 
  2769 
  2770 *** HOLCF ***
  2771 
  2772 * Discontinued special version of 'constdefs' (which used to support
  2773 continuous functions) in favor of the general Pure one with full
  2774 type-inference.
  2775 
  2776 * New simplification procedure for solving continuity conditions; it
  2777 is much faster on terms with many nested lambda abstractions (cubic
  2778 instead of exponential time).
  2779 
  2780 * New syntax for domain package: selector names are now optional.
  2781 Parentheses should be omitted unless argument is lazy, for example:
  2782 
  2783   domain 'a stream = cons "'a" (lazy "'a stream")
  2784 
  2785 * New command 'fixrec' for defining recursive functions with pattern
  2786 matching; defining multiple functions with mutual recursion is also
  2787 supported.  Patterns may include the constants cpair, spair, up, sinl,
  2788 sinr, or any data constructor defined by the domain package. The given
  2789 equations are proven as rewrite rules. See HOLCF/ex/Fixrec_ex.thy for
  2790 syntax and examples.
  2791 
  2792 * New commands 'cpodef' and 'pcpodef' for defining predicate subtypes
  2793 of cpo and pcpo types. Syntax is exactly like the 'typedef' command,
  2794 but the proof obligation additionally includes an admissibility
  2795 requirement. The packages generate instances of class cpo or pcpo,
  2796 with continuity and strictness theorems for Rep and Abs.
  2797 
  2798 * HOLCF: Many theorems have been renamed according to a more standard naming
  2799 scheme (INCOMPATIBILITY):
  2800 
  2801   foo_inject:  "foo$x = foo$y ==> x = y"
  2802   foo_eq:      "(foo$x = foo$y) = (x = y)"
  2803   foo_less:    "(foo$x << foo$y) = (x << y)"
  2804   foo_strict:  "foo$UU = UU"
  2805   foo_defined: "... ==> foo$x ~= UU"
  2806   foo_defined_iff: "(foo$x = UU) = (x = UU)"
  2807 
  2808 
  2809 *** ZF ***
  2810 
  2811 * ZF/ex: theories Group and Ring provide examples in abstract algebra,
  2812 including the First Isomorphism Theorem (on quotienting by the kernel
  2813 of a homomorphism).
  2814 
  2815 * ZF/Simplifier: install second copy of type solver that actually
  2816 makes use of TC rules declared to Isar proof contexts (or locales);
  2817 the old version is still required for ML proof scripts.
  2818 
  2819 
  2820 *** Cube ***
  2821 
  2822 * Converted to Isar theory format; use locales instead of axiomatic
  2823 theories.
  2824 
  2825 
  2826 *** ML ***
  2827 
  2828 * Pure/library.ML: added ##>, ##>>, #>> -- higher-order counterparts
  2829 for ||>, ||>>, |>>,
  2830 
  2831 * Pure/library.ML no longer defines its own option datatype, but uses
  2832 that of the SML basis, which has constructors NONE and SOME instead of
  2833 None and Some, as well as exception Option.Option instead of OPTION.
  2834 The functions the, if_none, is_some, is_none have been adapted
  2835 accordingly, while Option.map replaces apsome.
  2836 
  2837 * Pure/library.ML: the exception LIST has been given up in favour of
  2838 the standard exceptions Empty and Subscript, as well as
  2839 Library.UnequalLengths.  Function like Library.hd and Library.tl are
  2840 superceded by the standard hd and tl functions etc.
  2841 
  2842 A number of basic list functions are no longer exported to the ML
  2843 toplevel, as they are variants of predefined functions.  The following
  2844 suggests how one can translate existing code:
  2845 
  2846     rev_append xs ys = List.revAppend (xs, ys)
  2847     nth_elem (i, xs) = List.nth (xs, i)
  2848     last_elem xs = List.last xs
  2849     flat xss = List.concat xss
  2850     seq fs = List.app fs
  2851     partition P xs = List.partition P xs
  2852     mapfilter f xs = List.mapPartial f xs
  2853 
  2854 * Pure/library.ML: several combinators for linear functional
  2855 transformations, notably reverse application and composition:
  2856 
  2857   x |> f                f #> g
  2858   (x, y) |-> f          f #-> g
  2859 
  2860 * Pure/library.ML: introduced/changed precedence of infix operators:
  2861 
  2862   infix 1 |> |-> ||> ||>> |>> |>>> #> #->;
  2863   infix 2 ?;
  2864   infix 3 o oo ooo oooo;
  2865   infix 4 ~~ upto downto;
  2866 
  2867 Maybe INCOMPATIBILITY when any of those is used in conjunction with other
  2868 infix operators.
  2869 
  2870 * Pure/library.ML: natural list combinators fold, fold_rev, and
  2871 fold_map support linear functional transformations and nesting.  For
  2872 example:
  2873 
  2874   fold f [x1, ..., xN] y =
  2875     y |> f x1 |> ... |> f xN
  2876 
  2877   (fold o fold) f [xs1, ..., xsN] y =
  2878     y |> fold f xs1 |> ... |> fold f xsN
  2879 
  2880   fold f [x1, ..., xN] =
  2881     f x1 #> ... #> f xN
  2882 
  2883   (fold o fold) f [xs1, ..., xsN] =
  2884     fold f xs1 #> ... #> fold f xsN
  2885 
  2886 * Pure/library.ML: the following selectors on type 'a option are
  2887 available:
  2888 
  2889   the:               'a option -> 'a  (*partial*)
  2890   these:             'a option -> 'a  where 'a = 'b list
  2891   the_default: 'a -> 'a option -> 'a
  2892   the_list:          'a option -> 'a list
  2893 
  2894 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2895 basic operations for association lists, following natural argument
  2896 order; moreover the explicit equality predicate passed here avoids
  2897 potentially expensive polymorphic runtime equality checks.
  2898 The old functions may be expressed as follows:
  2899 
  2900   assoc = uncurry (AList.lookup (op =))
  2901   assocs = these oo AList.lookup (op =)
  2902   overwrite = uncurry (AList.update (op =)) o swap
  2903 
  2904 * Pure/General: structure AList (cf. Pure/General/alist.ML) provides
  2905 
  2906   val make: ('a -> 'b) -> 'a list -> ('a * 'b) list
  2907   val find: ('a * 'b -> bool) -> ('c * 'b) list -> 'a -> 'c list
  2908 
  2909 replacing make_keylist and keyfilter (occassionally used)
  2910 Naive rewrites:
  2911 
  2912   make_keylist = AList.make
  2913   keyfilter = AList.find (op =)
  2914 
  2915 * eq_fst and eq_snd now take explicit equality parameter, thus
  2916   avoiding eqtypes. Naive rewrites:
  2917 
  2918     eq_fst = eq_fst (op =)
  2919     eq_snd = eq_snd (op =)
  2920 
  2921 * Removed deprecated apl and apr (rarely used).
  2922   Naive rewrites:
  2923 
  2924     apl (n, op) =>>= curry op n
  2925     apr (op, m) =>>= fn n => op (n, m)
  2926 
  2927 * Pure/General: structure OrdList (cf. Pure/General/ord_list.ML)
  2928 provides a reasonably efficient light-weight implementation of sets as
  2929 lists.
  2930 
  2931 * Pure/General: generic tables (cf. Pure/General/table.ML) provide a
  2932 few new operations; existing lookup and update are now curried to
  2933 follow natural argument order (for use with fold etc.);
  2934 INCOMPATIBILITY, use (uncurry Symtab.lookup) etc. as last resort.
  2935 
  2936 * Pure/General: output via the Isabelle channels of
  2937 writeln/warning/error etc. is now passed through Output.output, with a
  2938 hook for arbitrary transformations depending on the print_mode
  2939 (cf. Output.add_mode -- the first active mode that provides a output
  2940 function wins).  Already formatted output may be embedded into further
  2941 text via Output.raw; the result of Pretty.string_of/str_of and derived
  2942 functions (string_of_term/cterm/thm etc.) is already marked raw to
  2943 accommodate easy composition of diagnostic messages etc.  Programmers
  2944 rarely need to care about Output.output or Output.raw at all, with
  2945 some notable exceptions: Output.output is required when bypassing the
  2946 standard channels (writeln etc.), or in token translations to produce
  2947 properly formatted results; Output.raw is required when capturing
  2948 already output material that will eventually be presented to the user
  2949 a second time.  For the default print mode, both Output.output and
  2950 Output.raw have no effect.
  2951 
  2952 * Pure/General: Output.time_accumulator NAME creates an operator ('a
  2953 -> 'b) -> 'a -> 'b to measure runtime and count invocations; the
  2954 cumulative results are displayed at the end of a batch session.
  2955 
  2956 * Pure/General: File.sysify_path and File.quote_sysify path have been
  2957 replaced by File.platform_path and File.shell_path (with appropriate
  2958 hooks).  This provides a clean interface for unusual systems where the
  2959 internal and external process view of file names are different.
  2960 
  2961 * Pure: more efficient orders for basic syntactic entities: added
  2962 fast_string_ord, fast_indexname_ord, fast_term_ord; changed sort_ord
  2963 and typ_ord to use fast_string_ord and fast_indexname_ord (term_ord is
  2964 NOT affected); structures Symtab, Vartab, Typtab, Termtab use the fast
  2965 orders now -- potential INCOMPATIBILITY for code that depends on a
  2966 particular order for Symtab.keys, Symtab.dest, etc. (consider using
  2967 Library.sort_strings on result).
  2968 
  2969 * Pure/term.ML: combinators fold_atyps, fold_aterms, fold_term_types,
  2970 fold_types traverse types/terms from left to right, observing natural
  2971 argument order.  Supercedes previous foldl_XXX versions, add_frees,
  2972 add_vars etc. have been adapted as well: INCOMPATIBILITY.
  2973 
  2974 * Pure: name spaces have been refined, with significant changes of the
  2975 internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
  2976 to extern(_table).  The plain name entry path is superceded by a
  2977 general 'naming' context, which also includes the 'policy' to produce
  2978 a fully qualified name and external accesses of a fully qualified
  2979 name; NameSpace.extend is superceded by context dependent
  2980 Sign.declare_name.  Several theory and proof context operations modify
  2981 the naming context.  Especially note Theory.restore_naming and
  2982 ProofContext.restore_naming to get back to a sane state; note that
  2983 Theory.add_path is no longer sufficient to recover from
  2984 Theory.absolute_path in particular.
  2985 
  2986 * Pure: new flags short_names (default false) and unique_names
  2987 (default true) for controlling output of qualified names.  If
  2988 short_names is set, names are printed unqualified.  If unique_names is
  2989 reset, the name prefix is reduced to the minimum required to achieve
  2990 the original result when interning again, even if there is an overlap
  2991 with earlier declarations.
  2992 
  2993 * Pure/TheoryDataFun: change of the argument structure; 'prep_ext' is
  2994 now 'extend', and 'merge' gets an additional Pretty.pp argument
  2995 (useful for printing error messages).  INCOMPATIBILITY.
  2996 
  2997 * Pure: major reorganization of the theory context.  Type Sign.sg and
  2998 Theory.theory are now identified, referring to the universal
  2999 Context.theory (see Pure/context.ML).  Actual signature and theory
  3000 content is managed as theory data.  The old code and interfaces were
  3001 spread over many files and structures; the new arrangement introduces
  3002 considerable INCOMPATIBILITY to gain more clarity:
  3003 
  3004   Context -- theory management operations (name, identity, inclusion,
  3005     parents, ancestors, merge, etc.), plus generic theory data;
  3006 
  3007   Sign -- logical signature and syntax operations (declaring consts,
  3008     types, etc.), plus certify/read for common entities;
  3009 
  3010   Theory -- logical theory operations (stating axioms, definitions,
  3011     oracles), plus a copy of logical signature operations (consts,
  3012     types, etc.); also a few basic management operations (Theory.copy,
  3013     Theory.merge, etc.)
  3014 
  3015 The most basic sign_of operations (Theory.sign_of, Thm.sign_of_thm
  3016 etc.) as well as the sign field in Thm.rep_thm etc. have been retained
  3017 for convenience -- they merely return the theory.
  3018 
  3019 * Pure: type Type.tsig is superceded by theory in most interfaces.
  3020 
  3021 * Pure: the Isar proof context type is already defined early in Pure
  3022 as Context.proof (note that ProofContext.context and Proof.context are
  3023 aliases, where the latter is the preferred name).  This enables other
  3024 Isabelle components to refer to that type even before Isar is present.
  3025 
  3026 * Pure/sign/theory: discontinued named name spaces (i.e. classK,
  3027 typeK, constK, axiomK, oracleK), but provide explicit operations for
  3028 any of these kinds.  For example, Sign.intern typeK is now
  3029 Sign.intern_type, Theory.hide_space Sign.typeK is now
  3030 Theory.hide_types.  Also note that former
  3031 Theory.hide_classes/types/consts are now
  3032 Theory.hide_classes_i/types_i/consts_i, while the non '_i' versions
  3033 internalize their arguments!  INCOMPATIBILITY.
  3034 
  3035 * Pure: get_thm interface (of PureThy and ProofContext) expects
  3036 datatype thmref (with constructors Name and NameSelection) instead of
  3037 plain string -- INCOMPATIBILITY;
  3038 
  3039 * Pure: cases produced by proof methods specify options, where NONE
  3040 means to remove case bindings -- INCOMPATIBILITY in
  3041 (RAW_)METHOD_CASES.
  3042 
  3043 * Pure: the following operations retrieve axioms or theorems from a
  3044 theory node or theory hierarchy, respectively:
  3045 
  3046   Theory.axioms_of: theory -> (string * term) list
  3047   Theory.all_axioms_of: theory -> (string * term) list
  3048   PureThy.thms_of: theory -> (string * thm) list
  3049   PureThy.all_thms_of: theory -> (string * thm) list
  3050 
  3051 * Pure: print_tac now outputs the goal through the trace channel.
  3052 
  3053 * Isar toplevel: improved diagnostics, mostly for Poly/ML only.
  3054 Reference Toplevel.debug (default false) controls detailed printing
  3055 and tracing of low-level exceptions; Toplevel.profiling (default 0)
  3056 controls execution profiling -- set to 1 for time and 2 for space
  3057 (both increase the runtime).
  3058 
  3059 * Isar session: The initial use of ROOT.ML is now always timed,
  3060 i.e. the log will show the actual process times, in contrast to the
  3061 elapsed wall-clock time that the outer shell wrapper produces.
  3062 
  3063 * Simplifier: improved handling of bound variables (nameless
  3064 representation, avoid allocating new strings).  Simprocs that invoke
  3065 the Simplifier recursively should use Simplifier.inherit_bounds to
  3066 avoid local name clashes.  Failure to do so produces warnings
  3067 "Simplifier: renamed bound variable ..."; set Simplifier.debug_bounds
  3068 for further details.
  3069 
  3070 * ML functions legacy_bindings and use_legacy_bindings produce ML fact
  3071 bindings for all theorems stored within a given theory; this may help
  3072 in porting non-Isar theories to Isar ones, while keeping ML proof
  3073 scripts for the time being.
  3074 
  3075 * ML operator HTML.with_charset specifies the charset begin used for
  3076 generated HTML files.  For example:
  3077 
  3078   HTML.with_charset "utf-8" use_thy "Hebrew";
  3079   HTML.with_charset "utf-8" use_thy "Chinese";
  3080 
  3081 
  3082 *** System ***
  3083 
  3084 * Allow symlinks to all proper Isabelle executables (Isabelle,
  3085 isabelle, isatool etc.).
  3086 
  3087 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
  3088 isatool doc, isatool mkdir, display_drafts etc.).
  3089 
  3090 * isatool usedir: option -f allows specification of the ML file to be
  3091 used by Isabelle; default is ROOT.ML.
  3092 
  3093 * New isatool version outputs the version identifier of the Isabelle
  3094 distribution being used.
  3095 
  3096 * HOL: new isatool dimacs2hol converts files in DIMACS CNF format
  3097 (containing Boolean satisfiability problems) into Isabelle/HOL
  3098 theories.
  3099 
  3100 
  3101 
  3102 New in Isabelle2004 (April 2004)
  3103 --------------------------------
  3104 
  3105 *** General ***
  3106 
  3107 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
  3108   Replaces linorder.ML.
  3109 
  3110 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
  3111   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
  3112   (\<a>...\<z>), are now considered normal letters, and can therefore
  3113   be used anywhere where an ASCII letter (a...zA...Z) has until
  3114   now. COMPATIBILITY: This obviously changes the parsing of some
  3115   terms, especially where a symbol has been used as a binder, say
  3116   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
  3117   as an identifier.  Fix it by inserting a space around former
  3118   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
  3119   existing theory and ML files.
  3120 
  3121 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
  3122 
  3123 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
  3124   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
  3125   a normal (but invisible) letter. For multiple letter subscripts repeat
  3126   \<^isub> like this: x\<^isub>1\<^isub>2.
  3127 
  3128 * Pure: There are now sub-/superscripts that can span more than one
  3129   character. Text between \<^bsub> and \<^esub> is set in subscript in
  3130   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
  3131   superscript. The new control characters are not identifier parts.
  3132 
  3133 * Pure: Control-symbols of the form \<^raw:...> will literally print the
  3134   content of "..." to the latex file instead of \isacntrl... . The "..."
  3135   may consist of any printable characters excluding the end bracket >.
  3136 
  3137 * Pure: Using new Isar command "finalconsts" (or the ML functions
  3138   Theory.add_finals or Theory.add_finals_i) it is now possible to
  3139   declare constants "final", which prevents their being given a definition
  3140   later.  It is useful for constants whose behaviour is fixed axiomatically
  3141   rather than definitionally, such as the meta-logic connectives.
  3142 
  3143 * Pure: 'instance' now handles general arities with general sorts
  3144   (i.e. intersections of classes),
  3145 
  3146 * Presentation: generated HTML now uses a CSS style sheet to make layout
  3147   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
  3148   It can be changed to alter the colors/layout of generated pages.
  3149 
  3150 
  3151 *** Isar ***
  3152 
  3153 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
  3154   cut_tac, subgoal_tac and thin_tac:
  3155   - Now understand static (Isar) contexts.  As a consequence, users of Isar
  3156     locales are no longer forced to write Isar proof scripts.
  3157     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
  3158     emulations.
  3159   - INCOMPATIBILITY: names of variables to be instantiated may no
  3160     longer be enclosed in quotes.  Instead, precede variable name with `?'.
  3161     This is consistent with the instantiation attribute "where".
  3162 
  3163 * Attributes "where" and "of":
  3164   - Now take type variables of instantiated theorem into account when reading
  3165     the instantiation string.  This fixes a bug that caused instantiated
  3166     theorems to have too special types in some circumstances.
  3167   - "where" permits explicit instantiations of type variables.
  3168 
  3169 * Calculation commands "moreover" and "also" no longer interfere with
  3170   current facts ("this"), admitting arbitrary combinations with "then"
  3171   and derived forms.
  3172 
  3173 * Locales:
  3174   - Goal statements involving the context element "includes" no longer
  3175     generate theorems with internal delta predicates (those ending on
  3176     "_axioms") in the premise.
  3177     Resolve particular premise with <locale>.intro to obtain old form.
  3178   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
  3179     specification and "includes" elements in goal statement.
  3180   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
  3181     [intro?] and [elim?] (respectively) by default.
  3182   - Experimental command for instantiation of locales in proof contexts:
  3183         instantiate <label>[<attrs>]: <loc>
  3184     Instantiates locale <loc> and adds all its theorems to the current context
  3185     taking into account their attributes.  Label and attrs are optional
  3186     modifiers, like in theorem declarations.  If present, names of
  3187     instantiated theorems are qualified with <label>, and the attributes
  3188     <attrs> are applied after any attributes these theorems might have already.
  3189       If the locale has assumptions, a chained fact of the form
  3190     "<loc> t1 ... tn" is expected from which instantiations of the parameters
  3191     are derived.  The command does not support old-style locales declared
  3192     with "locale (open)".
  3193       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
  3194 
  3195 * HOL: Tactic emulation methods induct_tac and case_tac understand static
  3196   (Isar) contexts.
  3197 
  3198 
  3199 *** HOL ***
  3200 
  3201 * Proof import: new image HOL4 contains the imported library from
  3202   the HOL4 system with about 2500 theorems. It is imported by
  3203   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
  3204   can be used like any other Isabelle image.  See
  3205   HOL/Import/HOL/README for more information.
  3206 
  3207 * Simplifier:
  3208   - Much improved handling of linear and partial orders.
  3209     Reasoners for linear and partial orders are set up for type classes
  3210     "linorder" and "order" respectively, and are added to the default simpset
  3211     as solvers.  This means that the simplifier can build transitivity chains
  3212     to solve goals from the assumptions.
  3213   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
  3214     of blast or auto after simplification become unnecessary because the goal
  3215     is solved by simplification already.
  3216 
  3217 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
  3218     all proved in axiomatic type classes for semirings, rings and fields.
  3219 
  3220 * Numerics:
  3221   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
  3222     now formalized using the Ring_and_Field theory mentioned above.
  3223   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
  3224     than before, because now they are set up once in a generic manner.
  3225   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
  3226     Look for the general versions in Ring_and_Field (and Power if they concern
  3227     exponentiation).
  3228 
  3229 * Type "rat" of the rational numbers is now available in HOL-Complex.
  3230 
  3231 * Records:
  3232   - Record types are now by default printed with their type abbreviation
  3233     instead of the list of all field types. This can be configured via
  3234     the reference "print_record_type_abbr".
  3235   - Simproc "record_upd_simproc" for simplification of multiple updates added
  3236     (not enabled by default).
  3237   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
  3238     EX x. x = sel r to True (not enabled by default).
  3239   - Tactic "record_split_simp_tac" to split and simplify records added.
  3240 
  3241 * 'specification' command added, allowing for definition by
  3242   specification.  There is also an 'ax_specification' command that
  3243   introduces the new constants axiomatically.
  3244 
  3245 * arith(_tac) is now able to generate counterexamples for reals as well.
  3246 
  3247 * HOL-Algebra: new locale "ring" for non-commutative rings.
  3248 
  3249 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
  3250   definitions, thanks to Sava Krsti\'{c} and John Matthews.
  3251 
  3252 * HOL-Matrix: a first theory for matrices in HOL with an application of
  3253   matrix theory to linear programming.
  3254 
  3255 * Unions and Intersections:
  3256   The latex output syntax of UN and INT has been changed
  3257   from "\Union x \in A. B" to "\Union_{x \in A} B"
  3258   i.e. the index formulae has become a subscript.
  3259   Similarly for "\Union x. B", and for \Inter instead of \Union.
  3260 
  3261 * Unions and Intersections over Intervals:
  3262   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
  3263   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
  3264   like in normal math, and corresponding versions for < and for intersection.
  3265 
  3266 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
  3267   lexicographic dictonary ordering has been added as "lexord".
  3268 
  3269 * ML: the legacy theory structures Int and List have been removed. They had
  3270   conflicted with ML Basis Library structures having the same names.
  3271 
  3272 * 'refute' command added to search for (finite) countermodels.  Only works
  3273   for a fragment of HOL.  The installation of an external SAT solver is
  3274   highly recommended.  See "HOL/Refute.thy" for details.
  3275 
  3276 * 'quickcheck' command: Allows to find counterexamples by evaluating
  3277   formulae under an assignment of free variables to random values.
  3278   In contrast to 'refute', it can deal with inductive datatypes,
  3279   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
  3280   for examples.
  3281 
  3282 
  3283 *** HOLCF ***
  3284 
  3285 * Streams now come with concatenation and are part of the HOLCF image
  3286 
  3287 
  3288 
  3289 New in Isabelle2003 (May 2003)
  3290 ------------------------------
  3291 
  3292 *** General ***
  3293 
  3294 * Provers/simplifier:
  3295 
  3296   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
  3297     Assumptions are now subject to complete mutual simplification,
  3298     not just from left to right. The simplifier now preserves
  3299     the order of assumptions.
  3300 
  3301     Potential INCOMPATIBILITY:
  3302 
  3303     -- simp sometimes diverges where the old version did
  3304        not, e.g. invoking simp on the goal
  3305 
  3306         [| P (f x); y = x; f x = f y |] ==> Q
  3307 
  3308        now gives rise to the infinite reduction sequence
  3309 
  3310         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
  3311 
  3312        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
  3313        kind of problem.
  3314 
  3315     -- Tactics combining classical reasoner and simplification (such as auto)
  3316        are also affected by this change, because many of them rely on
  3317        simp. They may sometimes diverge as well or yield a different numbers
  3318        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
  3319        in case of problems. Sometimes subsequent calls to the classical
  3320        reasoner will fail because a preceeding call to the simplifier too
  3321        eagerly simplified the goal, e.g. deleted redundant premises.
  3322 
  3323   - The simplifier trace now shows the names of the applied rewrite rules
  3324 
  3325   - You can limit the number of recursive invocations of the simplifier
  3326     during conditional rewriting (where the simplifie tries to solve the
  3327     conditions before applying the rewrite rule):
  3328     ML "simp_depth_limit := n"
  3329     where n is an integer. Thus you can force termination where previously
  3330     the simplifier would diverge.
  3331 
  3332   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
  3333 
  3334   - No longer aborts on failed congruence proof.  Instead, the
  3335     congruence is ignored.
  3336 
  3337 * Pure: New generic framework for extracting programs from constructive
  3338   proofs. See HOL/Extraction.thy for an example instantiation, as well
  3339   as HOL/Extraction for some case studies.
  3340 
  3341 * Pure: The main goal of the proof state is no longer shown by default, only
  3342 the subgoals. This behaviour is controlled by a new flag.
  3343    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
  3344 (ML: Proof.show_main_goal).
  3345 
  3346 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
  3347 rules whose conclusion matches subgoal 1:
  3348       PG menu: Isabelle/Isar -> Show me -> matching rules
  3349 The rules are ordered by how closely they match the subgoal.
  3350 In particular, rules that solve a subgoal outright are displayed first
  3351 (or rather last, the way they are printed).
  3352 (ML: ProofGeneral.print_intros())
  3353 
  3354 * Pure: New flag trace_unify_fail causes unification to print
  3355 diagnostic information (PG: in trace buffer) when it fails. This is
  3356 useful for figuring out why single step proofs like rule, erule or
  3357 assumption failed.
  3358 
  3359 * Pure: Locale specifications now produce predicate definitions
  3360 according to the body of text (covering assumptions modulo local
  3361 definitions); predicate "loc_axioms" covers newly introduced text,
  3362 while "loc" is cumulative wrt. all included locale expressions; the
  3363 latter view is presented only on export into the global theory
  3364 context; potential INCOMPATIBILITY, use "(open)" option to fall back
  3365 on the old view without predicates;
  3366 
  3367 * Pure: predefined locales "var" and "struct" are useful for sharing
  3368 parameters (as in CASL, for example); just specify something like
  3369 ``var x + var y + struct M'' as import;
  3370 
  3371 * Pure: improved thms_containing: proper indexing of facts instead of
  3372 raw theorems; check validity of results wrt. current name space;
  3373 include local facts of proof configuration (also covers active
  3374 locales), cover fixed variables in index; may use "_" in term
  3375 specification; an optional limit for the number of printed facts may
  3376 be given (the default is 40);
  3377 
  3378 * Pure: disallow duplicate fact bindings within new-style theory files
  3379 (batch-mode only);
  3380 
  3381 * Provers: improved induct method: assumptions introduced by case
  3382 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
  3383 the goal statement); "foo" still refers to all facts collectively;
  3384 
  3385 * Provers: the function blast.overloaded has been removed: all constants
  3386 are regarded as potentially overloaded, which improves robustness in exchange
  3387 for slight decrease in efficiency;
  3388 
  3389 * Provers/linorder: New generic prover for transitivity reasoning over
  3390 linear orders.  Note: this prover is not efficient!
  3391 
  3392 * Isar: preview of problems to finish 'show' now produce an error
  3393 rather than just a warning (in interactive mode);
  3394 
  3395 
  3396 *** HOL ***
  3397 
  3398 * arith(_tac)
  3399 
  3400  - Produces a counter example if it cannot prove a goal.
  3401    Note that the counter example may be spurious if the goal is not a formula
  3402    of quantifier-free linear arithmetic.
  3403    In ProofGeneral the counter example appears in the trace buffer.
  3404 
  3405  - Knows about div k and mod k where k is a numeral of type nat or int.
  3406 
  3407  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
  3408    linear arithmetic fails. This takes account of quantifiers and divisibility.
  3409    Presburger arithmetic can also be called explicitly via presburger(_tac).
  3410 
  3411 * simp's arithmetic capabilities have been enhanced a bit: it now
  3412 takes ~= in premises into account (by performing a case split);
  3413 
  3414 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
  3415 are distributed over a sum of terms;
  3416 
  3417 * New tactic "trans_tac" and method "trans" instantiate
  3418 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
  3419 "<=", "<" and "=").
  3420 
  3421 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
  3422 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
  3423 
  3424 * 'typedef' command has new option "open" to suppress the set
  3425 definition;
  3426 
  3427 * functions Min and Max on finite sets have been introduced (theory
  3428 Finite_Set);
  3429 
  3430 * attribute [symmetric] now works for relations as well; it turns
  3431 (x,y) : R^-1 into (y,x) : R, and vice versa;
  3432 
  3433 * induct over a !!-quantified statement (say !!x1..xn):
  3434   each "case" automatically performs "fix x1 .. xn" with exactly those names.
  3435 
  3436 * Map: `empty' is no longer a constant but a syntactic abbreviation for
  3437 %x. None. Warning: empty_def now refers to the previously hidden definition
  3438 of the empty set.
  3439 
  3440 * Algebra: formalization of classical algebra.  Intended as base for
  3441 any algebraic development in Isabelle.  Currently covers group theory
  3442 (up to Sylow's theorem) and ring theory (Universal Property of
  3443 Univariate Polynomials).  Contributions welcome;
  3444 
  3445 * GroupTheory: deleted, since its material has been moved to Algebra;
  3446 
  3447 * Complex: new directory of the complex numbers with numeric constants,
  3448 nonstandard complex numbers, and some complex analysis, standard and
  3449 nonstandard (Jacques Fleuriot);
  3450 
  3451 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
  3452 
  3453 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
  3454 Fleuriot);
  3455 
  3456 * Real/HahnBanach: updated and adapted to locales;
  3457 
  3458 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
  3459 Gray and Kramer);
  3460 
  3461 * UNITY: added the Meier-Sanders theory of progress sets;
  3462 
  3463 * MicroJava: bytecode verifier and lightweight bytecode verifier
  3464 as abstract algorithms, instantiated to the JVM;
  3465 
  3466 * Bali: Java source language formalization. Type system, operational
  3467 semantics, axiomatic semantics. Supported language features:
  3468 classes, interfaces, objects,virtual methods, static methods,
  3469 static/instance fields, arrays, access modifiers, definite
  3470 assignment, exceptions.
  3471 
  3472 
  3473 *** ZF ***
  3474 
  3475 * ZF/Constructible: consistency proof for AC (Gdel's constructible
  3476 universe, etc.);
  3477 
  3478 * Main ZF: virtually all theories converted to new-style format;
  3479 
  3480 
  3481 *** ML ***
  3482 
  3483 * Pure: Tactic.prove provides sane interface for internal proofs;
  3484 omits the infamous "standard" operation, so this is more appropriate
  3485 than prove_goalw_cterm in many situations (e.g. in simprocs);
  3486 
  3487 * Pure: improved error reporting of simprocs;
  3488 
  3489 * Provers: Simplifier.simproc(_i) provides sane interface for setting
  3490 up simprocs;
  3491 
  3492 
  3493 *** Document preparation ***
  3494 
  3495 * uses \par instead of \\ for line breaks in theory text. This may
  3496 shift some page breaks in large documents. To get the old behaviour
  3497 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
  3498 
  3499 * minimized dependencies of isabelle.sty and isabellesym.sty on
  3500 other packages
  3501 
  3502 * \<euro> now needs package babel/greek instead of marvosym (which
  3503 broke \Rightarrow)
  3504 
  3505 * normal size for \<zero>...\<nine> (uses \mathbf instead of
  3506 textcomp package)
  3507 
  3508 
  3509 
  3510 New in Isabelle2002 (March 2002)
  3511 --------------------------------
  3512 
  3513 *** Document preparation ***
  3514 
  3515 * greatly simplified document preparation setup, including more
  3516 graceful interpretation of isatool usedir -i/-d/-D options, and more
  3517 instructive isatool mkdir; users should basically be able to get
  3518 started with "isatool mkdir HOL Test && isatool make"; alternatively,
  3519 users may run a separate document processing stage manually like this:
  3520 "isatool usedir -D output HOL Test && isatool document Test/output";
  3521 
  3522 * theory dependency graph may now be incorporated into documents;
  3523 isatool usedir -g true will produce session_graph.eps/.pdf for use
  3524 with \includegraphics of LaTeX;
  3525 
  3526 * proper spacing of consecutive markup elements, especially text
  3527 blocks after section headings;
  3528 
  3529 * support bold style (for single symbols only), input syntax is like
  3530 this: "\<^bold>\<alpha>" or "\<^bold>A";
  3531 
  3532 * \<bullet> is now output as bold \cdot by default, which looks much
  3533 better in printed text;
  3534 
  3535 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
  3536 note that these symbols are currently unavailable in Proof General /
  3537 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
  3538 
  3539 * isatool latex no longer depends on changed TEXINPUTS, instead
  3540 isatool document copies the Isabelle style files to the target
  3541 location;
  3542 
  3543 
  3544 *** Isar ***
  3545 
  3546 * Pure/Provers: improved proof by cases and induction;
  3547   - 'case' command admits impromptu naming of parameters (such as
  3548     "case (Suc n)");
  3549   - 'induct' method divinates rule instantiation from the inductive
  3550     claim; no longer requires excessive ?P bindings for proper
  3551     instantiation of cases;
  3552   - 'induct' method properly enumerates all possibilities of set/type
  3553     rules; as a consequence facts may be also passed through *type*
  3554     rules without further ado;
  3555   - 'induct' method now derives symbolic cases from the *rulified*
  3556     rule (before it used to rulify cases stemming from the internal
  3557     atomized version); this means that the context of a non-atomic
  3558     statement becomes is included in the hypothesis, avoiding the
  3559     slightly cumbersome show "PROP ?case" form;
  3560   - 'induct' may now use elim-style induction rules without chaining
  3561     facts, using ``missing'' premises from the goal state; this allows
  3562     rules stemming from inductive sets to be applied in unstructured
  3563     scripts, while still benefitting from proper handling of non-atomic
  3564     statements; NB: major inductive premises need to be put first, all
  3565     the rest of the goal is passed through the induction;
  3566   - 'induct' proper support for mutual induction involving non-atomic
  3567     rule statements (uses the new concept of simultaneous goals, see
  3568     below);
  3569   - append all possible rule selections, but only use the first
  3570     success (no backtracking);
  3571   - removed obsolete "(simplified)" and "(stripped)" options of methods;
  3572   - undeclared rule case names default to numbers 1, 2, 3, ...;
  3573   - added 'print_induct_rules' (covered by help item in recent Proof
  3574     General versions);
  3575   - moved induct/cases attributes to Pure, methods to Provers;
  3576   - generic method setup instantiated for FOL and HOL;
  3577 
  3578 * Pure: support multiple simultaneous goal statements, for example
  3579 "have a: A and b: B" (same for 'theorem' etc.); being a pure
  3580 meta-level mechanism, this acts as if several individual goals had
  3581 been stated separately; in particular common proof methods need to be
  3582 repeated in order to cover all claims; note that a single elimination
  3583 step is *not* sufficient to establish the two conjunctions, so this
  3584 fails:
  3585 
  3586   assume "A & B" then have A and B ..   (*".." fails*)
  3587 
  3588 better use "obtain" in situations as above; alternative refer to
  3589 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
  3590 
  3591 * Pure: proper integration with ``locales''; unlike the original
  3592 version by Florian Kammller, Isar locales package high-level proof
  3593 contexts rather than raw logical ones (e.g. we admit to include
  3594 attributes everywhere); operations on locales include merge and
  3595 rename; support for implicit arguments (``structures''); simultaneous
  3596 type-inference over imports and text; see also HOL/ex/Locales.thy for
  3597 some examples;
  3598 
  3599 * Pure: the following commands have been ``localized'', supporting a
  3600 target locale specification "(in name)": 'lemma', 'theorem',
  3601 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
  3602 stored both within the locale and at the theory level (exported and
  3603 qualified by the locale name);
  3604 
  3605 * Pure: theory goals may now be specified in ``long'' form, with
  3606 ad-hoc contexts consisting of arbitrary locale elements. for example
  3607 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
  3608 definitions may be given, too); the result is a meta-level rule with
  3609 the context elements being discharged in the obvious way;
  3610 
  3611 * Pure: new proof command 'using' allows to augment currently used
  3612 facts after a goal statement ('using' is syntactically analogous to
  3613 'apply', but acts on the goal's facts only); this allows chained facts
  3614 to be separated into parts given before and after a claim, as in
  3615 ``from a and b have C using d and e <proof>'';
  3616 
  3617 * Pure: renamed "antecedent" case to "rule_context";
  3618 
  3619 * Pure: new 'judgment' command records explicit information about the
  3620 object-logic embedding (used by several tools internally); no longer
  3621 use hard-wired "Trueprop";
  3622 
  3623 * Pure: added 'corollary' command;
  3624 
  3625 * Pure: fixed 'token_translation' command;
  3626 
  3627 * Pure: removed obsolete 'exported' attribute;
  3628 
  3629 * Pure: dummy pattern "_" in is/let is now automatically lifted over
  3630 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
  3631 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
  3632 
  3633 * Pure: method 'atomize' presents local goal premises as object-level
  3634 statements (atomic meta-level propositions); setup controlled via
  3635 rewrite rules declarations of 'atomize' attribute; example
  3636 application: 'induct' method with proper rule statements in improper
  3637 proof *scripts*;
  3638 
  3639 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
  3640 now consider the syntactic context of assumptions, giving a better
  3641 chance to get type-inference of the arguments right (this is
  3642 especially important for locales);
  3643 
  3644 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  3645 mode;
  3646 
  3647 * Pure/obtain: the formal conclusion "thesis", being marked as
  3648 ``internal'', may no longer be reference directly in the text;
  3649 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  3650 situations;
  3651 
  3652 * Pure: generic 'sym' attribute which declares a rule both as pure
  3653 'elim?' and for the 'symmetric' operation;
  3654 
  3655 * Pure: marginal comments ``--'' may now occur just anywhere in the
  3656 text; the fixed correlation with particular command syntax has been
  3657 discontinued;
  3658 
  3659 * Pure: new method 'rules' is particularly well-suited for proof
  3660 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  3661 but often produces more compact proof terms with less detours;
  3662 
  3663 * Pure/Provers/classical: simplified integration with pure rule
  3664 attributes and methods; the classical "intro?/elim?/dest?"
  3665 declarations coincide with the pure ones; the "rule" method no longer
  3666 includes classically swapped intros; "intro" and "elim" methods no
  3667 longer pick rules from the context; also got rid of ML declarations
  3668 AddXIs/AddXEs/AddXDs; all of this has some potential for
  3669 INCOMPATIBILITY;
  3670 
  3671 * Provers/classical: attribute 'swapped' produces classical inversions
  3672 of introduction rules;
  3673 
  3674 * Provers/simplifier: 'simplified' attribute may refer to explicit
  3675 rules instead of full simplifier context; 'iff' attribute handles
  3676 conditional rules;
  3677 
  3678 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  3679 
  3680 * HOL: 'recdef' now fails on unfinished automated proofs, use
  3681 "(permissive)" option to recover old behavior;
  3682 
  3683 * HOL: 'inductive' no longer features separate (collective) attributes
  3684 for 'intros' (was found too confusing);
  3685 
  3686 * HOL: properly declared induction rules less_induct and
  3687 wf_induct_rule;
  3688 
  3689 
  3690 *** HOL ***
  3691 
  3692 * HOL: moved over to sane numeral syntax; the new policy is as
  3693 follows:
  3694 
  3695   - 0 and 1 are polymorphic constants, which are defined on any
  3696   numeric type (nat, int, real etc.);
  3697 
  3698   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  3699   binary representation internally;
  3700 
  3701   - type nat has special constructor Suc, and generally prefers Suc 0
  3702   over 1::nat and Suc (Suc 0) over 2::nat;
  3703 
  3704 This change may cause significant problems of INCOMPATIBILITY; here
  3705 are some hints on converting existing sources:
  3706 
  3707   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  3708   entities, so expressions involving "-" (unary or binary minus) need
  3709   to be spaced properly;
  3710 
  3711   - existing occurrences of "1" may need to be constraint "1::nat" or
  3712   even replaced by Suc 0; similar for old "2";
  3713 
  3714   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  3715 
  3716   - remove all special provisions on numerals in proofs;
  3717 
  3718 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  3719 representation (depends on bin_arith_simps in the default context);
  3720 
  3721 * HOL: symbolic syntax for x^2 (numeral 2);
  3722 
  3723 * HOL: the class of all HOL types is now called "type" rather than
  3724 "term"; INCOMPATIBILITY, need to adapt references to this type class
  3725 in axclass/classes, instance/arities, and (usually rare) occurrences
  3726 in typings (of consts etc.); internally the class is called
  3727 "HOL.type", ML programs should refer to HOLogic.typeS;
  3728 
  3729 * HOL/record package improvements:
  3730   - new derived operations "fields" to build a partial record section,
  3731     "extend" to promote a fixed record to a record scheme, and
  3732     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  3733     declared as simp by default;
  3734   - shared operations ("more", "fields", etc.) now need to be always
  3735     qualified) --- potential INCOMPATIBILITY;
  3736   - removed "make_scheme" operations (use "make" with "extend") --
  3737     INCOMPATIBILITY;
  3738   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  3739   - provides cases/induct rules for use with corresponding Isar
  3740     methods (for concrete records, record schemes, concrete more
  3741     parts, and schematic more parts -- in that order);
  3742   - internal definitions directly based on a light-weight abstract
  3743     theory of product types over typedef rather than datatype;
  3744 
  3745 * HOL: generic code generator for generating executable ML code from
  3746 specifications; specific support for HOL constructs such as inductive
  3747 datatypes and sets, as well as recursive functions; can be invoked
  3748 via 'generate_code' theory section;
  3749 
  3750 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  3751 
  3752 * HOL: consolidated and renamed several theories.  In particular:
  3753         Ord.thy has been absorbed into HOL.thy
  3754         String.thy has been absorbed into List.thy
  3755 
  3756 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  3757 (beware of argument permutation!);
  3758 
  3759 * HOL: linorder_less_split superseded by linorder_cases;
  3760 
  3761 * HOL/List: "nodups" renamed to "distinct";
  3762 
  3763 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  3764 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  3765   - Ex_def has changed, now need to use some_eq_ex
  3766 
  3767 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  3768 in this (rare) case use:
  3769 
  3770   delSWrapper "split_all_tac"
  3771   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  3772 
  3773 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  3774 MAY FAIL;
  3775 
  3776 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  3777 Isabelle's type classes, ^ on functions and relations has too general
  3778 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  3779 necessary to attach explicit type constraints;
  3780 
  3781 * HOL/Relation: the prefix name of the infix "O" has been changed from
  3782 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  3783 renamed accordingly (eg "compI" -> "rel_compI").
  3784 
  3785 * HOL: syntax translations now work properly with numerals and records
  3786 expressions;
  3787 
  3788 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  3789 of "lam" -- INCOMPATIBILITY;
  3790 
  3791 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  3792 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  3793 renamed "Product_Type.unit";
  3794 
  3795 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  3796 
  3797 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  3798 the "cases" method);
  3799 
  3800 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  3801 Florian Kammller);
  3802 
  3803 * HOL/IMP: updated and converted to new-style theory format; several
  3804 parts turned into readable document, with proper Isar proof texts and
  3805 some explanations (by Gerwin Klein);
  3806 
  3807 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  3808 
  3809 * HOL-Hyperreal is now a logic image;
  3810 
  3811 
  3812 *** HOLCF ***
  3813 
  3814 * Isar: consts/constdefs supports mixfix syntax for continuous
  3815 operations;
  3816 
  3817 * Isar: domain package adapted to new-style theory format, e.g. see
  3818 HOLCF/ex/Dnat.thy;
  3819 
  3820 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  3821 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  3822 lift.induct_tac, always use UU instead of Undef;
  3823 
  3824 * HOLCF/IMP: updated and converted to new-style theory;
  3825 
  3826 
  3827 *** ZF ***
  3828 
  3829 * Isar: proper integration of logic-specific tools and packages,
  3830 including theory commands '(co)inductive', '(co)datatype',
  3831 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  3832 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  3833 
  3834 * theory Main no longer includes AC; for the Axiom of Choice, base
  3835 your theory on Main_ZFC;
  3836 
  3837 * the integer library now covers quotients and remainders, with many
  3838 laws relating division to addition, multiplication, etc.;
  3839 
  3840 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  3841 typeless version of the formalism;
  3842 
  3843 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  3844 format;
  3845 
  3846 * ZF/Induct: new directory for examples of inductive definitions,
  3847 including theory Multiset for multiset orderings; converted to
  3848 new-style theory format;
  3849 
  3850 * ZF: many new theorems about lists, ordinals, etc.;
  3851 
  3852 
  3853 *** General ***
  3854 
  3855 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  3856 variable proof controls level of detail: 0 = no proofs (only oracle
  3857 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  3858 also ref manual for further ML interfaces;
  3859 
  3860 * Pure/axclass: removed obsolete ML interface
  3861 goal_subclass/goal_arity;
  3862 
  3863 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  3864 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  3865 separate tokens, so expressions involving minus need to be spaced
  3866 properly;
  3867 
  3868 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  3869 rather than "infixl" or "infixr";
  3870 
  3871 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  3872 sort constraint specifications in type inference; e.g. "x::_::foo"
  3873 ensures that the type of "x" is of sort "foo" (but not necessarily a
  3874 type variable);
  3875 
  3876 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  3877 control output of nested => (types); the default behavior is
  3878 "type_brackets";
  3879 
  3880 * Pure/syntax: builtin parse translation for "_constify" turns valued
  3881 tokens into AST constants;
  3882 
  3883 * Pure/syntax: prefer later declarations of translations and print
  3884 translation functions; potential INCOMPATIBILITY: need to reverse
  3885 multiple declarations for same syntax element constant;
  3886 
  3887 * Pure/show_hyps reset by default (in accordance to existing Isar
  3888 practice);
  3889 
  3890 * Provers/classical: renamed addaltern to addafter, addSaltern to
  3891 addSafter;
  3892 
  3893 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  3894 as well;
  3895 
  3896 * system: tested support for MacOS X; should be able to get Isabelle +
  3897 Proof General to work in a plain Terminal after installing Poly/ML
  3898 (e.g. from the Isabelle distribution area) and GNU bash alone
  3899 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  3900 support requires further installations, e.g. from
  3901 http://fink.sourceforge.net/);
  3902 
  3903 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  3904 
  3905 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  3906 of 40 MB), cf. ML_OPTIONS;
  3907 
  3908 * system: Proof General keywords specification is now part of the
  3909 Isabelle distribution (see etc/isar-keywords.el);
  3910 
  3911 * system: support for persistent Proof General sessions (refrain from
  3912 outdating all loaded theories on startup); user may create writable
  3913 logic images like this: ``isabelle -q HOL Test'';
  3914 
  3915 * system: smart selection of Isabelle process versus Isabelle
  3916 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  3917 run both "isabelle" and "Isabelle" even if file names are badly
  3918 damaged (executable inspects the case of the first letter of its own
  3919 name); added separate "isabelle-process" and "isabelle-interface";
  3920 
  3921 * system: refrain from any attempt at filtering input streams; no
  3922 longer support ``8bit'' encoding of old isabelle font, instead proper
  3923 iso-latin characters may now be used; the related isatools
  3924 "symbolinput" and "nonascii" have disappeared as well;
  3925 
  3926 * system: removed old "xterm" interface (the print modes "xterm" and
  3927 "xterm_color" are still available for direct use in a suitable
  3928 terminal);
  3929 
  3930 
  3931 
  3932 New in Isabelle99-2 (February 2001)
  3933 -----------------------------------
  3934 
  3935 *** Overview of INCOMPATIBILITIES ***
  3936 
  3937 * HOL: please note that theories in the Library and elsewhere often use the
  3938 new-style (Isar) format; to refer to their theorems in an ML script you must
  3939 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  3940 
  3941 * HOL: inductive package no longer splits induction rule aggressively,
  3942 but only as far as specified by the introductions given; the old
  3943 format may be recovered via ML function complete_split_rule or attribute
  3944 'split_rule (complete)';
  3945 
  3946 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  3947 gfp_Tarski to gfp_unfold;
  3948 
  3949 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  3950 
  3951 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  3952 relation); infix "^^" has been renamed "``"; infix "``" has been
  3953 renamed "`"; "univalent" has been renamed "single_valued";
  3954 
  3955 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  3956 operation;
  3957 
  3958 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  3959 
  3960 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  3961 
  3962 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  3963 consequence, it is no longer monotonic wrt. the local goal context
  3964 (which is now passed through the inductive cases);
  3965 
  3966 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  3967 \<gg> to \<ggreater>;
  3968 
  3969 
  3970 *** Document preparation ***
  3971 
  3972 * \isabellestyle{NAME} selects version of Isabelle output (currently
  3973 available: are "it" for near math-mode best-style output, "sl" for
  3974 slanted text style, and "tt" for plain type-writer; if no
  3975 \isabellestyle command is given, output is according to slanted
  3976 type-writer);
  3977 
  3978 * support sub/super scripts (for single symbols only), input syntax is
  3979 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  3980 
  3981 * some more standard symbols; see Appendix A of the system manual for
  3982 the complete list of symbols defined in isabellesym.sty;
  3983 
  3984 * improved isabelle style files; more abstract symbol implementation
  3985 (should now use \isamath{...} and \isatext{...} in custom symbol
  3986 definitions);
  3987 
  3988 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  3989 state; Note that presentation of goal states does not conform to
  3990 actual human-readable proof documents.  Please do not include goal
  3991 states into document output unless you really know what you are doing!
  3992 
  3993 * proper indentation of antiquoted output with proportional LaTeX
  3994 fonts;
  3995 
  3996 * no_document ML operator temporarily disables LaTeX document
  3997 generation;
  3998 
  3999 * isatool unsymbolize tunes sources for plain ASCII communication;
  4000 
  4001 
  4002 *** Isar ***
  4003 
  4004 * Pure: Isar now suffers initial goal statements to contain unbound
  4005 schematic variables (this does not conform to actual readable proof
  4006 documents, due to unpredictable outcome and non-compositional proof
  4007 checking); users who know what they are doing may use schematic goals
  4008 for Prolog-style synthesis of proven results;
  4009 
  4010 * Pure: assumption method (an implicit finishing) now handles actual
  4011 rules as well;
  4012 
  4013 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  4014 initial goal, declare "that" only as Pure intro (only for single
  4015 steps); the "that" rule assumption may now be involved in implicit
  4016 finishing, thus ".." becomes a feasible for trivial obtains;
  4017 
  4018 * Pure: default proof step now includes 'intro_classes'; thus trivial
  4019 instance proofs may be performed by "..";
  4020 
  4021 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  4022 statements as well;
  4023 
  4024 * Pure: more robust selection of calculational rules;
  4025 
  4026 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  4027 rule (as well as the assumption rule);
  4028 
  4029 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  4030 lemmas, using the graph browser tool;
  4031 
  4032 * Pure: predict failure of "show" in interactive mode;
  4033 
  4034 * Pure: 'thms_containing' now takes actual terms as arguments;
  4035 
  4036 * HOL: improved method 'induct' --- now handles non-atomic goals
  4037 (potential INCOMPATIBILITY); tuned error handling;
  4038 
  4039 * HOL: cases and induct rules now provide explicit hints about the
  4040 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  4041 any remaining facts are inserted into the goal verbatim;
  4042 
  4043 * HOL: local contexts (aka cases) may now contain term bindings as
  4044 well; the 'cases' and 'induct' methods new provide a ?case binding for
  4045 the result to be shown in each case;
  4046 
  4047 * HOL: added 'recdef_tc' command;
  4048 
  4049 * isatool convert assists in eliminating legacy ML scripts;
  4050 
  4051 
  4052 *** HOL ***
  4053 
  4054 * HOL/Library: a collection of generic theories to be used together
  4055 with main HOL; the theory loader path already includes this directory
  4056 by default; the following existing theories have been moved here:
  4057 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  4058 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  4059 
  4060 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  4061 modelling and verification task performed in Isabelle/HOL +
  4062 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  4063 
  4064 * HOL/Algebra: special summation operator SUM no longer exists, it has
  4065 been replaced by setsum; infix 'assoc' now has priority 50 (like
  4066 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  4067 'domain', this makes the theory consistent with mathematical
  4068 literature;
  4069 
  4070 * HOL basics: added overloaded operations "inverse" and "divide"
  4071 (infix "/"), syntax for generic "abs" operation, generic summation
  4072 operator \<Sum>;
  4073 
  4074 * HOL/typedef: simplified package, provide more useful rules (see also
  4075 HOL/subset.thy);
  4076 
  4077 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  4078 now expressed as a proper nested rule (old-style tactic scripts may
  4079 require atomize_strip_tac to cope with non-atomic premises);
  4080 
  4081 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  4082 to "split_conv" (old name still available for compatibility);
  4083 
  4084 * HOL: improved concrete syntax for strings (e.g. allows translation
  4085 rules with string literals);
  4086 
  4087 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  4088  and Fleuriot's mechanization of analysis, including the transcendental
  4089  functions for the reals;
  4090 
  4091 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  4092 
  4093 
  4094 *** CTT ***
  4095 
  4096 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  4097 "lam" is displayed as TWO lambda-symbols
  4098 
  4099 * CTT: theory Main now available, containing everything (that is, Bool
  4100 and Arith);
  4101 
  4102 
  4103 *** General ***
  4104 
  4105 * Pure: the Simplifier has been implemented properly as a derived rule
  4106 outside of the actual kernel (at last!); the overall performance
  4107 penalty in practical applications is about 50%, while reliability of
  4108 the Isabelle inference kernel has been greatly improved;
  4109 
  4110 * print modes "brackets" and "no_brackets" control output of nested =>
  4111 (types) and ==> (props); the default behaviour is "brackets";
  4112 
  4113 * Provers: fast_tac (and friends) now handle actual object-logic rules
  4114 as assumptions as well;
  4115 
  4116 * system: support Poly/ML 4.0;
  4117 
  4118 * system: isatool install handles KDE version 1 or 2;
  4119 
  4120 
  4121 
  4122 New in Isabelle99-1 (October 2000)
  4123 ----------------------------------
  4124 
  4125 *** Overview of INCOMPATIBILITIES ***
  4126 
  4127 * HOL: simplification of natural numbers is much changed; to partly
  4128 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  4129 issue the following ML commands:
  4130 
  4131   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  4132   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  4133 
  4134 * HOL: simplification no longer dives into case-expressions; this is
  4135 controlled by "t.weak_case_cong" for each datatype t;
  4136 
  4137 * HOL: nat_less_induct renamed to less_induct;
  4138 
  4139 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  4140 fixsome to patch .thy and .ML sources automatically;
  4141 
  4142   select_equality  -> some_equality
  4143   select_eq_Ex     -> some_eq_ex
  4144   selectI2EX       -> someI2_ex
  4145   selectI2         -> someI2
  4146   selectI          -> someI
  4147   select1_equality -> some1_equality
  4148   Eps_sym_eq       -> some_sym_eq_trivial
  4149   Eps_eq           -> some_eq_trivial
  4150 
  4151 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  4152 
  4153 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  4154 instead);
  4155 
  4156 * HOL: the recursion equations generated by 'recdef' are now called
  4157 f.simps instead of f.rules;
  4158 
  4159 * HOL: qed_spec_mp now also handles bounded ALL as well;
  4160 
  4161 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  4162 sometimes be needed;
  4163 
  4164 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  4165 
  4166 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  4167 
  4168 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  4169 product is now "<*>" instead of "Times"; the lexicographic product is
  4170 now "<*lex*>" instead of "**";
  4171 
  4172 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  4173 of main HOL, but was unused); better use HOL's datatype package;
  4174 
  4175 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  4176 the old syntax may be recovered as follows:
  4177 
  4178   syntax (symbols)
  4179     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  4180       (infixl "\\<oplus>" 100)
  4181 
  4182 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4183 
  4184 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  4185 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  4186 internally;
  4187 
  4188 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  4189 changed from A/r to A//r;
  4190 
  4191 * ZF: new treatment of arithmetic (nat & int) may break some old
  4192 proofs;
  4193 
  4194 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  4195 rulify -> rule_format, elimify -> elim_format, ...);
  4196 
  4197 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4198 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  4199 should have to change intro!! to intro? only); replaced "delrule" by
  4200 "rule del";
  4201 
  4202 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  4203 
  4204 * Provers: strengthened force_tac by using new first_best_tac;
  4205 
  4206 * LaTeX document preparation: several changes of isabelle.sty (see
  4207 lib/texinputs);
  4208 
  4209 
  4210 *** Document preparation ***
  4211 
  4212 * formal comments (text blocks etc.) in new-style theories may now
  4213 contain antiquotations of thm/prop/term/typ/text to be presented
  4214 according to latex print mode; concrete syntax is like this:
  4215 @{term[show_types] "f(x) = a + x"};
  4216 
  4217 * isatool mkdir provides easy setup of Isabelle session directories,
  4218 including proper document sources;
  4219 
  4220 * generated LaTeX sources are now deleted after successful run
  4221 (isatool document -c); may retain a copy somewhere else via -D option
  4222 of isatool usedir;
  4223 
  4224 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  4225 style files, achieving self-contained LaTeX sources and simplifying
  4226 LaTeX debugging;
  4227 
  4228 * old-style theories now produce (crude) LaTeX output as well;
  4229 
  4230 * browser info session directories are now self-contained (may be put
  4231 on WWW server seperately); improved graphs of nested sessions; removed
  4232 graph for 'all sessions';
  4233 
  4234 * several improvements in isabelle style files; \isabellestyle{it}
  4235 produces fake math mode output; \isamarkupheader is now \section by
  4236 default; see lib/texinputs/isabelle.sty etc.;
  4237 
  4238 
  4239 *** Isar ***
  4240 
  4241 * Isar/Pure: local results and corresponding term bindings are now
  4242 subject to Hindley-Milner polymorphism (similar to ML); this
  4243 accommodates incremental type-inference very nicely;
  4244 
  4245 * Isar/Pure: new derived language element 'obtain' supports
  4246 generalized existence reasoning;
  4247 
  4248 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  4249 support accumulation of results, without applying any rules yet;
  4250 useful to collect intermediate results without explicit name
  4251 references, and for use with transitivity rules with more than 2
  4252 premises;
  4253 
  4254 * Isar/Pure: scalable support for case-analysis type proofs: new
  4255 'case' language element refers to local contexts symbolically, as
  4256 produced by certain proof methods; internally, case names are attached
  4257 to theorems as "tags";
  4258 
  4259 * Isar/Pure: theory command 'hide' removes declarations from
  4260 class/type/const name spaces;
  4261 
  4262 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  4263 indicate potential overloading;
  4264 
  4265 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  4266 
  4267 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  4268 "{a,b,c}" instead of {a,b,c};
  4269 
  4270 * Isar/Pure now provides its own version of intro/elim/dest
  4271 attributes; useful for building new logics, but beware of confusion
  4272 with the version in Provers/classical;
  4273 
  4274 * Isar/Pure: the local context of (non-atomic) goals is provided via
  4275 case name 'antecedent';
  4276 
  4277 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  4278 to the current context is now done automatically);
  4279 
  4280 * Isar/Pure: theory command 'method_setup' provides a simple interface
  4281 for definining proof methods in ML;
  4282 
  4283 * Isar/Provers: intro/elim/dest attributes changed; renamed
  4284 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  4285 most cases, one should have to change intro!! to intro? only);
  4286 replaced "delrule" by "rule del";
  4287 
  4288 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  4289 'symmetric' attribute (the latter supercedes [RS sym]);
  4290 
  4291 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  4292 method modifier); 'simp' method: 'only:' modifier removes loopers as
  4293 well (including splits);
  4294 
  4295 * Isar/Provers: Simplifier and Classical methods now support all kind
  4296 of modifiers used in the past, including 'cong', 'iff', etc.
  4297 
  4298 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  4299 of Simplifier and Classical reasoner);
  4300 
  4301 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  4302 now support named cases; major packages (inductive, datatype, primrec,
  4303 recdef) support case names and properly name parameters;
  4304 
  4305 * Isar/HOL: new transitivity rules for substitution in inequalities --
  4306 monotonicity conditions are extracted to be proven at end of
  4307 calculations;
  4308 
  4309 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  4310 method anyway;
  4311 
  4312 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  4313 split_if split_if_asm; datatype package provides theorems foo.splits =
  4314 foo.split foo.split_asm for each datatype;
  4315 
  4316 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  4317 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  4318 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  4319 use "(cases (simplified))" method in proper proof texts);
  4320 
  4321 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  4322 
  4323 * Isar: names of theorems etc. may be natural numbers as well;
  4324 
  4325 * Isar: 'pr' command: optional arguments for goals_limit and
  4326 ProofContext.prems_limit; no longer prints theory contexts, but only
  4327 proof states;
  4328 
  4329 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  4330 additional print modes to be specified; e.g. "pr(latex)" will print
  4331 proof state according to the Isabelle LaTeX style;
  4332 
  4333 * Isar: improved support for emulating tactic scripts, including proof
  4334 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  4335 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  4336 (for HOL datatypes);
  4337 
  4338 * Isar: simplified (more robust) goal selection of proof methods: 1st
  4339 goal, all goals, or explicit goal specifier (tactic emulation); thus
  4340 'proof method scripts' have to be in depth-first order;
  4341 
  4342 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  4343 
  4344 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  4345 should instead use individual commands for printing items
  4346 (print_commands, print_methods etc.);
  4347 
  4348 * Isar: added 'nothing' --- the empty list of theorems;
  4349 
  4350 
  4351 *** HOL ***
  4352 
  4353 * HOL/MicroJava: formalization of a fragment of Java, together with a
  4354 corresponding virtual machine and a specification of its bytecode
  4355 verifier and a lightweight bytecode verifier, including proofs of
  4356 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  4357 Cornelia Pusch (see also the homepage of project Bali at
  4358 http://isabelle.in.tum.de/Bali/);
  4359 
  4360 * HOL/Algebra: new theory of rings and univariate polynomials, by
  4361 Clemens Ballarin;
  4362 
  4363 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  4364 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  4365 Rasmussen;
  4366 
  4367 * HOL/Lattice: fundamental concepts of lattice theory and order
  4368 structures, including duals, properties of bounds versus algebraic
  4369 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  4370 Theorem for complete lattices etc.; may also serve as a demonstration
  4371 for abstract algebraic reasoning using axiomatic type classes, and
  4372 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  4373 
  4374 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  4375 von Oheimb;
  4376 
  4377 * HOL/IMPP: extension of IMP with local variables and mutually
  4378 recursive procedures, by David von Oheimb;
  4379 
  4380 * HOL/Lambda: converted into new-style theory and document;
  4381 
  4382 * HOL/ex/Multiquote: example of multiple nested quotations and
  4383 anti-quotations -- basically a generalized version of de-Bruijn
  4384 representation; very useful in avoiding lifting of operations;
  4385 
  4386 * HOL/record: added general record equality rule to simpset; fixed
  4387 select-update simplification procedure to handle extended records as
  4388 well; admit "r" as field name;
  4389 
  4390 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  4391 other numeric types and also as the identity of groups, rings, etc.;
  4392 
  4393 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  4394 Types nat and int belong to this axclass;
  4395 
  4396 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  4397    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  4398    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  4399   two terms #m*u and #n*u are replaced by #(m+n)*u
  4400     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  4401   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  4402     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  4403 
  4404 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  4405 powerful prover for predicate logic but knows nothing of clasets; see
  4406 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  4407 
  4408 * HOL: new version of "case_tac" subsumes both boolean case split and
  4409 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  4410 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  4411 
  4412 * HOL: simplification no longer dives into case-expressions: only the
  4413 selector expression is simplified, but not the remaining arms; to
  4414 enable full simplification of case-expressions for datatype t, you may
  4415 remove t.weak_case_cong from the simpset, either globally (Delcongs
  4416 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  4417 
  4418 * HOL/recdef: the recursion equations generated by 'recdef' for
  4419 function 'f' are now called f.simps instead of f.rules; if all
  4420 termination conditions are proved automatically, these simplification
  4421 rules are added to the simpset, as in primrec; rules may be named
  4422 individually as well, resulting in a separate list of theorems for
  4423 each equation;
  4424 
  4425 * HOL/While is a new theory that provides a while-combinator. It
  4426 permits the definition of tail-recursive functions without the
  4427 provision of a termination measure. The latter is necessary once the
  4428 invariant proof rule for while is applied.
  4429 
  4430 * HOL: new (overloaded) notation for the set of elements below/above
  4431 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  4432 
  4433 * HOL: theorems impI, allI, ballI bound as "strip";
  4434 
  4435 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  4436 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  4437 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  4438 
  4439 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  4440 
  4441 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  4442 main HOL, but was unused);
  4443 
  4444 * HOL: fewer consts declared as global (e.g. have to refer to
  4445 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  4446 
  4447 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  4448 in case of overlap with user translations (e.g. judgements over
  4449 tuples); (note that the underlying logical represenation is still
  4450 bogus);
  4451 
  4452 
  4453 *** ZF ***
  4454 
  4455 * ZF: simplification automatically cancels common terms in arithmetic
  4456 expressions over nat and int;
  4457 
  4458 * ZF: new treatment of nat to minimize type-checking: all operators
  4459 coerce their operands to a natural number using the function natify,
  4460 making the algebraic laws unconditional;
  4461 
  4462 * ZF: as above, for int: operators coerce their operands to an integer
  4463 using the function intify;
  4464 
  4465 * ZF: the integer library now contains many of the usual laws for the
  4466 orderings, including $<=, and monotonicity laws for $+ and $*;
  4467 
  4468 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  4469 simplification;
  4470 
  4471 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  4472 to the simplifier and classical reasoner simultaneously;
  4473 
  4474 
  4475 *** General ***
  4476 
  4477 * Provers: blast_tac now handles actual object-logic rules as
  4478 assumptions; note that auto_tac uses blast_tac internally as well;
  4479 
  4480 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  4481 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  4482 
  4483 * Provers: delrules now handles destruct rules as well (no longer need
  4484 explicit make_elim);
  4485 
  4486 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  4487   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4488 use instead the strong form,
  4489   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  4490 in HOL, FOL and ZF the function cla_make_elim will create such rules
  4491 from destruct-rules;
  4492 
  4493 * Provers: Simplifier.easy_setup provides a fast path to basic
  4494 Simplifier setup for new object-logics;
  4495 
  4496 * Pure: AST translation rules no longer require constant head on LHS;
  4497 
  4498 * Pure: improved name spaces: ambiguous output is qualified; support
  4499 for hiding of names;
  4500 
  4501 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  4502 XSYMBOL_HOME; no longer need to do manual configuration in most
  4503 situations;
  4504 
  4505 * system: compression of ML heaps images may now be controlled via -c
  4506 option of isabelle and isatool usedir (currently only observed by
  4507 Poly/ML);
  4508 
  4509 * system: isatool installfonts may handle X-Symbol fonts as well (very
  4510 useful for remote X11);
  4511 
  4512 * system: provide TAGS file for Isabelle sources;
  4513 
  4514 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  4515 order;
  4516 
  4517 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  4518 timing flag supersedes proof_timing and Toplevel.trace;
  4519 
  4520 * ML: new combinators |>> and |>>> for incremental transformations
  4521 with secondary results (e.g. certain theory extensions):
  4522 
  4523 * ML: PureThy.add_defs gets additional argument to indicate potential
  4524 overloading (usually false);
  4525 
  4526 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  4527 results;
  4528 
  4529 
  4530 
  4531 New in Isabelle99 (October 1999)
  4532 --------------------------------
  4533 
  4534 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4535 
  4536 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  4537 are no longer simplified.  (This allows the simplifier to unfold recursive
  4538 functional programs.)  To restore the old behaviour, declare
  4539 
  4540     Delcongs [if_weak_cong];
  4541 
  4542 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  4543 complement;
  4544 
  4545 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  4546 
  4547 * HOL/datatype: mutual_induct_tac no longer exists --
  4548   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  4549 
  4550 * HOL/typedef: fixed type inference for representing set; type
  4551 arguments now have to occur explicitly on the rhs as type constraints;
  4552 
  4553 * ZF: The con_defs part of an inductive definition may no longer refer
  4554 to constants declared in the same theory;
  4555 
  4556 * HOL, ZF: the function mk_cases, generated by the inductive
  4557 definition package, has lost an argument.  To simplify its result, it
  4558 uses the default simpset instead of a supplied list of theorems.
  4559 
  4560 * HOL/List: the constructors of type list are now Nil and Cons;
  4561 
  4562 * Simplifier: the type of the infix ML functions
  4563         setSSolver addSSolver setSolver addSolver
  4564 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  4565 for packaging solvers. A solver is created via
  4566         mk_solver: string -> (thm list -> int -> tactic) -> solver
  4567 where the string argument is only a comment.
  4568 
  4569 
  4570 *** Proof tools ***
  4571 
  4572 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  4573 decision procedure for linear arithmetic. Currently it is used for
  4574 types `nat', `int', and `real' in HOL (see below); it can, should and
  4575 will be instantiated for other types and logics as well.
  4576 
  4577 * The simplifier now accepts rewrite rules with flexible heads, eg
  4578      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  4579   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  4580   matching.
  4581 
  4582 
  4583 *** General ***
  4584 
  4585 * New Isabelle/Isar subsystem provides an alternative to traditional
  4586 tactical theorem proving; together with the ProofGeneral/isar user
  4587 interface it offers an interactive environment for developing human
  4588 readable proof documents (Isar == Intelligible semi-automated
  4589 reasoning); for further information see isatool doc isar-ref,
  4590 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  4591 
  4592 * improved and simplified presentation of theories: better HTML markup
  4593 (including colors), graph views in several sizes; isatool usedir now
  4594 provides a proper interface for user theories (via -P option); actual
  4595 document preparation based on (PDF)LaTeX is available as well (for
  4596 new-style theories only); see isatool doc system for more information;
  4597 
  4598 * native support for Proof General, both for classic Isabelle and
  4599 Isabelle/Isar;
  4600 
  4601 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  4602 using the graph browser tool;
  4603 
  4604 * Isabelle manuals now also available as PDF;
  4605 
  4606 * theory loader rewritten from scratch (may not be fully
  4607 bug-compatible); old loadpath variable has been replaced by show_path,
  4608 add_path, del_path, reset_path functions; new operations such as
  4609 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  4610 isatool doc ref);
  4611 
  4612 * improved isatool install: option -k creates KDE application icon,
  4613 option -p DIR installs standalone binaries;
  4614 
  4615 * added ML_PLATFORM setting (useful for cross-platform installations);
  4616 more robust handling of platform specific ML images for SML/NJ;
  4617 
  4618 * the settings environment is now statically scoped, i.e. it is never
  4619 created again in sub-processes invoked from isabelle, isatool, or
  4620 Isabelle;
  4621 
  4622 * path element specification '~~' refers to '$ISABELLE_HOME';
  4623 
  4624 * in locales, the "assumes" and "defines" parts may be omitted if
  4625 empty;
  4626 
  4627 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  4628 long arrows);
  4629 
  4630 * new print_mode "HTML";
  4631 
  4632 * new flag show_tags controls display of tags of theorems (which are
  4633 basically just comments that may be attached by some tools);
  4634 
  4635 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  4636 mode and goal output format:
  4637 
  4638 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  4639 244c244
  4640 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  4641 ---
  4642 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  4643 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  4644 181c181
  4645 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  4646 ---
  4647 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  4648 
  4649 * function bind_thms stores lists of theorems (cf. bind_thm);
  4650 
  4651 * new shorthand tactics ftac, eatac, datac, fatac;
  4652 
  4653 * qed (and friends) now accept "" as result name; in that case the
  4654 theorem is not stored, but proper checks and presentation of the
  4655 result still apply;
  4656 
  4657 * theorem database now also indexes constants "Trueprop", "all",
  4658 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  4659 
  4660 
  4661 *** HOL ***
  4662 
  4663 ** HOL arithmetic **
  4664 
  4665 * There are now decision procedures for linear arithmetic over nat and
  4666 int:
  4667 
  4668 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  4669 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  4670 are treated as atomic; subformulae not involving type `nat' or `int'
  4671 are ignored; quantified subformulae are ignored unless they are
  4672 positive universal or negative existential. The tactic has to be
  4673 invoked by hand and can be a little bit slow. In particular, the
  4674 running time is exponential in the number of occurrences of `min' and
  4675 `max', and `-' on `nat'.
  4676 
  4677 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  4678 (negated) (in)equalities among the premises and the conclusion into
  4679 account (i.e. no compound formulae) and does not know about `min' and
  4680 `max', and `-' on `nat'. It is fast and is used automatically by the
  4681 simplifier.
  4682 
  4683 NB: At the moment, these decision procedures do not cope with mixed
  4684 nat/int formulae where the two parts interact, such as `m < n ==>
  4685 int(m) < int(n)'.
  4686 
  4687 * HOL/Numeral provides a generic theory of numerals (encoded
  4688 efficiently as bit strings); setup for types nat/int/real is in place;
  4689 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  4690 int, existing theories and proof scripts may require a few additional
  4691 type constraints;
  4692 
  4693 * integer division and remainder can now be performed on constant
  4694 arguments;
  4695 
  4696 * many properties of integer multiplication, division and remainder
  4697 are now available;
  4698 
  4699 * An interface to the Stanford Validity Checker (SVC) is available through the
  4700 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  4701 are proved automatically.  SVC must be installed separately, and its results
  4702 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  4703 invocation of the underlying oracle).  For SVC see
  4704   http://verify.stanford.edu/SVC
  4705 
  4706 * IsaMakefile: the HOL-Real target now builds an actual image;
  4707 
  4708 
  4709 ** HOL misc **
  4710 
  4711 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  4712 (in Isabelle/Isar) -- by Gertrud Bauer;
  4713 
  4714 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  4715 analysis for assembly languages with subtypes;
  4716 
  4717 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  4718 -- avoids syntactic ambiguities and treats state, transition, and
  4719 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  4720 changed syntax and (many) tactics;
  4721 
  4722 * HOL/inductive: Now also handles more general introduction rules such
  4723   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  4724   theorems are now maintained within the theory (maintained via the
  4725   "mono" attribute);
  4726 
  4727 * HOL/datatype: Now also handles arbitrarily branching datatypes
  4728   (using function types) such as
  4729 
  4730   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  4731 
  4732 * HOL/record: record_simproc (part of the default simpset) takes care
  4733 of selectors applied to updated records; record_split_tac is no longer
  4734 part of the default claset; update_defs may now be removed from the
  4735 simpset in many cases; COMPATIBILITY: old behavior achieved by
  4736 
  4737   claset_ref () := claset() addSWrapper record_split_wrapper;
  4738   Delsimprocs [record_simproc]
  4739 
  4740 * HOL/typedef: fixed type inference for representing set; type
  4741 arguments now have to occur explicitly on the rhs as type constraints;
  4742 
  4743 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  4744 names rather than an ML expression;
  4745 
  4746 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  4747 supplied later.  Program schemes can be defined, such as
  4748     "While B C s = (if B s then While B C (C s) else s)"
  4749 where the well-founded relation can be chosen after B and C have been given.
  4750 
  4751 * HOL/List: the constructors of type list are now Nil and Cons;
  4752 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  4753 course, ML tools referring to List.list.op # etc. have to be adapted;
  4754 
  4755 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  4756 disabled by default; run isabelle with option -m HOL to get back to
  4757 the original Gordon/HOL-style output;
  4758 
  4759 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  4760 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  4761 
  4762 * HOL basic syntax simplified (more orthogonal): all variants of
  4763 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  4764 Eps operator is provided as well: "SOME x. P[x]";
  4765 
  4766 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  4767 
  4768 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  4769 thus available for user theories;
  4770 
  4771 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  4772 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  4773 time;
  4774 
  4775 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  4776 several times and then mp;
  4777 
  4778 
  4779 *** LK ***
  4780 
  4781 * the notation <<...>> is now available as a notation for sequences of
  4782 formulas;
  4783 
  4784 * the simplifier is now installed
  4785 
  4786 * the axiom system has been generalized (thanks to Soren Heilmann)
  4787 
  4788 * the classical reasoner now has a default rule database
  4789 
  4790 
  4791 *** ZF ***
  4792 
  4793 * new primrec section allows primitive recursive functions to be given
  4794 directly (as in HOL) over datatypes and the natural numbers;
  4795 
  4796 * new tactics induct_tac and exhaust_tac for induction (or case
  4797 analysis) over datatypes and the natural numbers;
  4798 
  4799 * the datatype declaration of type T now defines the recursor T_rec;
  4800 
  4801 * simplification automatically does freeness reasoning for datatype
  4802 constructors;
  4803 
  4804 * automatic type-inference, with AddTCs command to insert new
  4805 type-checking rules;
  4806 
  4807 * datatype introduction rules are now added as Safe Introduction rules
  4808 to the claset;
  4809 
  4810 * the syntax "if P then x else y" is now available in addition to
  4811 if(P,x,y);
  4812 
  4813 
  4814 *** Internal programming interfaces ***
  4815 
  4816 * tuned simplifier trace output; new flag debug_simp;
  4817 
  4818 * structures Vartab / Termtab (instances of TableFun) offer efficient
  4819 tables indexed by indexname_ord / term_ord (compatible with aconv);
  4820 
  4821 * AxClass.axclass_tac lost the theory argument;
  4822 
  4823 * tuned current_goals_markers semantics: begin / end goal avoids
  4824 printing empty lines;
  4825 
  4826 * removed prs and prs_fn hook, which was broken because it did not
  4827 include \n in its semantics, forcing writeln to add one
  4828 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  4829 string -> unit if you really want to output text without newline;
  4830 
  4831 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  4832 plain output, interface builders may have to enable 'isabelle_font'
  4833 mode to get Isabelle font glyphs as before;
  4834 
  4835 * refined token_translation interface; INCOMPATIBILITY: output length
  4836 now of type real instead of int;
  4837 
  4838 * theory loader actions may be traced via new ThyInfo.add_hook
  4839 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  4840 your own database of information attached to *whole* theories -- as
  4841 opposed to intra-theory data slots offered via TheoryDataFun;
  4842 
  4843 * proper handling of dangling sort hypotheses (at last!);
  4844 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  4845 extra sort hypotheses that can be witnessed from the type signature;
  4846 the force_strip_shyps flag is gone, any remaining shyps are simply
  4847 left in the theorem (with a warning issued by strip_shyps_warning);
  4848 
  4849 
  4850 
  4851 New in Isabelle98-1 (October 1998)
  4852 ----------------------------------
  4853 
  4854 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  4855 
  4856 * several changes of automated proof tools;
  4857 
  4858 * HOL: major changes to the inductive and datatype packages, including
  4859 some minor incompatibilities of theory syntax;
  4860 
  4861 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  4862 called `inj_on';
  4863 
  4864 * HOL: removed duplicate thms in Arith:
  4865   less_imp_add_less  should be replaced by  trans_less_add1
  4866   le_imp_add_le      should be replaced by  trans_le_add1
  4867 
  4868 * HOL: unary minus is now overloaded (new type constraints may be
  4869 required);
  4870 
  4871 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  4872 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  4873 now taken as an integer constant.
  4874 
  4875 * Pure: ML function 'theory_of' renamed to 'theory';
  4876 
  4877 
  4878 *** Proof tools ***
  4879 
  4880 * Simplifier:
  4881   1. Asm_full_simp_tac is now more aggressive.
  4882      1. It will sometimes reorient premises if that increases their power to
  4883         simplify.
  4884      2. It does no longer proceed strictly from left to right but may also
  4885         rotate premises to achieve further simplification.
  4886      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  4887      old Asm_full_simp_tac in that it does not rotate premises.
  4888   2. The simplifier now knows a little bit about nat-arithmetic.
  4889 
  4890 * Classical reasoner: wrapper mechanism for the classical reasoner now
  4891 allows for selected deletion of wrappers, by introduction of names for
  4892 wrapper functionals.  This implies that addbefore, addSbefore,
  4893 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  4894 and that adding two tactics with the same name overwrites the first
  4895 one (emitting a warning).
  4896   type wrapper = (int -> tactic) -> (int -> tactic)
  4897   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  4898   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  4899   delWrapper, delSWrapper: claset *  string            -> claset
  4900   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  4901 
  4902 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  4903 semantics; addbefore now affects only the unsafe part of step_tac
  4904 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  4905 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  4906 by Force_tac;
  4907 
  4908 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  4909 compWrapper; added safe wrapper (and access functions for it);
  4910 
  4911 * HOL/split_all_tac is now much faster and fails if there is nothing
  4912 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  4913 and the names of the automatically generated variables have changed.
  4914 split_all_tac has moved within claset() from unsafe wrappers to safe
  4915 wrappers, which means that !!-bound variables are split much more
  4916 aggressively, and safe_tac and clarify_tac now split such variables.
  4917 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  4918 Note: the same holds for record_split_tac, which does the job of
  4919 split_all_tac for record fields.
  4920 
  4921 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  4922 permanently to the default simpset using Addsplits just like
  4923 Addsimps. They can be removed via Delsplits just like
  4924 Delsimps. Lower-case versions are also available.
  4925 
  4926 * HOL/Simplifier: The rule split_if is now part of the default
  4927 simpset. This means that the simplifier will eliminate all occurrences
  4928 of if-then-else in the conclusion of a goal. To prevent this, you can
  4929 either remove split_if completely from the default simpset by
  4930 `Delsplits [split_if]' or remove it in a specific call of the
  4931 simplifier using `... delsplits [split_if]'.  You can also add/delete
  4932 other case splitting rules to/from the default simpset: every datatype
  4933 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  4934 t is the name of the datatype).
  4935 
  4936 * Classical reasoner / Simplifier combination: new force_tac (and
  4937 derivatives Force_tac, force) combines rewriting and classical
  4938 reasoning (and whatever other tools) similarly to auto_tac, but is
  4939 aimed to solve the given subgoal completely.
  4940 
  4941 
  4942 *** General ***
  4943 
  4944 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  4945 and `goalw': the theory is no longer needed as an explicit argument -
  4946 the current theory context is used; assumptions are no longer returned
  4947 at the ML-level unless one of them starts with ==> or !!; it is
  4948 recommended to convert to these new commands using isatool fixgoal
  4949 (backup your sources first!);
  4950 
  4951 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  4952 the current theory context, and 'theory' to lookup stored theories;
  4953 
  4954 * new theory section 'locale' for declaring constants, assumptions and
  4955 definitions that have local scope;
  4956 
  4957 * new theory section 'nonterminals' for purely syntactic types;
  4958 
  4959 * new theory section 'setup' for generic ML setup functions
  4960 (e.g. package initialization);
  4961 
  4962 * the distribution now includes Isabelle icons: see
  4963 lib/logo/isabelle-{small,tiny}.xpm;
  4964 
  4965 * isatool install - install binaries with absolute references to
  4966 ISABELLE_HOME/bin;
  4967 
  4968 * isatool logo -- create instances of the Isabelle logo (as EPS);
  4969 
  4970 * print mode 'emacs' reserved for Isamode;
  4971 
  4972 * support multiple print (ast) translations per constant name;
  4973 
  4974 * theorems involving oracles are now printed with a suffixed [!];
  4975 
  4976 
  4977 *** HOL ***
  4978 
  4979 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  4980 
  4981 * HOL/inductive package reorganized and improved: now supports mutual
  4982 definitions such as
  4983 
  4984   inductive EVEN ODD
  4985     intrs
  4986       null "0 : EVEN"
  4987       oddI "n : EVEN ==> Suc n : ODD"
  4988       evenI "n : ODD ==> Suc n : EVEN"
  4989 
  4990 new theorem list "elims" contains an elimination rule for each of the
  4991 recursive sets; inductive definitions now handle disjunctive premises
  4992 correctly (also ZF);
  4993 
  4994 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  4995 "mutual_induct" no longer exists - the induction rule is always
  4996 contained in "induct";
  4997 
  4998 
  4999 * HOL/datatype package re-implemented and greatly improved: now
  5000 supports mutually recursive datatypes such as
  5001 
  5002   datatype
  5003     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  5004             | SUM ('a aexp) ('a aexp)
  5005             | DIFF ('a aexp) ('a aexp)
  5006             | NUM 'a
  5007   and
  5008     'a bexp = LESS ('a aexp) ('a aexp)
  5009             | AND ('a bexp) ('a bexp)
  5010             | OR ('a bexp) ('a bexp)
  5011 
  5012 as well as indirectly recursive datatypes such as
  5013 
  5014   datatype
  5015     ('a, 'b) term = Var 'a
  5016                   | App 'b ((('a, 'b) term) list)
  5017 
  5018 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  5019 induction on mutually / indirectly recursive datatypes.
  5020 
  5021 Primrec equations are now stored in theory and can be accessed via
  5022 <function_name>.simps.
  5023 
  5024 INCOMPATIBILITIES:
  5025 
  5026   - Theories using datatypes must now have theory Datatype as an
  5027     ancestor.
  5028   - The specific <typename>.induct_tac no longer exists - use the
  5029     generic induct_tac instead.
  5030   - natE has been renamed to nat.exhaust - use exhaust_tac
  5031     instead of res_inst_tac ... natE. Note that the variable
  5032     names in nat.exhaust differ from the names in natE, this
  5033     may cause some "fragile" proofs to fail.
  5034   - The theorems split_<typename>_case and split_<typename>_case_asm
  5035     have been renamed to <typename>.split and <typename>.split_asm.
  5036   - Since default sorts of type variables are now handled correctly,
  5037     some datatype definitions may have to be annotated with explicit
  5038     sort constraints.
  5039   - Primrec definitions no longer require function name and type
  5040     of recursive argument.
  5041 
  5042 Consider using isatool fixdatatype to adapt your theories and proof
  5043 scripts to the new package (backup your sources first!).
  5044 
  5045 
  5046 * HOL/record package: considerably improved implementation; now
  5047 includes concrete syntax for record types, terms, updates; theorems
  5048 for surjective pairing and splitting !!-bound record variables; proof
  5049 support is as follows:
  5050 
  5051   1) standard conversions (selectors or updates applied to record
  5052 constructor terms) are part of the standard simpset;
  5053 
  5054   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  5055 made part of standard simpset and claset via addIffs;
  5056 
  5057   3) a tactic for record field splitting (record_split_tac) is part of
  5058 the standard claset (addSWrapper);
  5059 
  5060 To get a better idea about these rules you may retrieve them via
  5061 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  5062 the name of your record type.
  5063 
  5064 The split tactic 3) conceptually simplifies by the following rule:
  5065 
  5066   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  5067 
  5068 Thus any record variable that is bound by meta-all will automatically
  5069 blow up into some record constructor term, consequently the
  5070 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  5071 solve record problems automatically.
  5072 
  5073 
  5074 * reorganized the main HOL image: HOL/Integ and String loaded by
  5075 default; theory Main includes everything;
  5076 
  5077 * automatic simplification of integer sums and comparisons, using cancellation;
  5078 
  5079 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  5080 
  5081 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  5082 
  5083 * many new identities for unions, intersections, set difference, etc.;
  5084 
  5085 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  5086 called split_if, split_split, split_sum_case and split_nat_case (to go
  5087 with add/delsplits);
  5088 
  5089 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  5090 (?x::unit) = (); this is made part of the default simpset, which COULD
  5091 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  5092 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  5093 unit_abs_eta_conv is added in order to counter the effect of
  5094 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  5095 %u.f();
  5096 
  5097 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  5098 makes more sense);
  5099 
  5100 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5101   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5102   disjointness reasoning but breaking a few old proofs.
  5103 
  5104 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  5105 to 'converse' from 'inverse' (for compatibility with ZF and some
  5106 literature);
  5107 
  5108 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  5109 the well-founded relation;
  5110 
  5111 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  5112     Compl A.  The "Compl" syntax remains available as input syntax for this
  5113     release ONLY.
  5114 
  5115 * HOL/Update: new theory of function updates:
  5116     f(a:=b) == %x. if x=a then b else f x
  5117 may also be iterated as in f(a:=b,c:=d,...);
  5118 
  5119 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  5120 
  5121 * HOL/List:
  5122   - new function list_update written xs[i:=v] that updates the i-th
  5123     list position. May also be iterated as in xs[i:=a,j:=b,...].
  5124   - new function `upt' written [i..j(] which generates the list
  5125     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  5126     bound write [i..j], which is a shorthand for [i..j+1(].
  5127   - new lexicographic orderings and corresponding wellfoundedness theorems.
  5128 
  5129 * HOL/Arith:
  5130   - removed 'pred' (predecessor) function;
  5131   - generalized some theorems about n-1;
  5132   - many new laws about "div" and "mod";
  5133   - new laws about greatest common divisors (see theory ex/Primes);
  5134 
  5135 * HOL/Relation: renamed the relational operator r^-1 "converse"
  5136 instead of "inverse";
  5137 
  5138 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  5139   of the multiset ordering;
  5140 
  5141 * directory HOL/Real: a construction of the reals using Dedekind cuts
  5142   (not included by default);
  5143 
  5144 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  5145 
  5146 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  5147   programs, i.e. different program variables may have different types.
  5148 
  5149 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5150   [previously, this check worked only if the rewrite rule was unconditional]
  5151   Now rew can involve either definitions or equalities (either == or =).
  5152 
  5153 
  5154 *** ZF ***
  5155 
  5156 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  5157   only the theorems proved on ZF.ML;
  5158 
  5159 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  5160   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  5161   disjointness reasoning but breaking a few old proofs.
  5162 
  5163 * ZF/Update: new theory of function updates
  5164     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  5165   may also be iterated as in f(a:=b,c:=d,...);
  5166 
  5167 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  5168 
  5169 * calling (stac rew i) now fails if "rew" has no effect on the goal
  5170   [previously, this check worked only if the rewrite rule was unconditional]
  5171   Now rew can involve either definitions or equalities (either == or =).
  5172 
  5173 * case_tac provided for compatibility with HOL
  5174     (like the old excluded_middle_tac, but with subgoals swapped)
  5175 
  5176 
  5177 *** Internal programming interfaces ***
  5178 
  5179 * Pure: several new basic modules made available for general use, see
  5180 also src/Pure/README;
  5181 
  5182 * improved the theory data mechanism to support encapsulation (data
  5183 kind name replaced by private Object.kind, acting as authorization
  5184 key); new type-safe user interface via functor TheoryDataFun; generic
  5185 print_data function becomes basically useless;
  5186 
  5187 * removed global_names compatibility flag -- all theory declarations
  5188 are qualified by default;
  5189 
  5190 * module Pure/Syntax now offers quote / antiquote translation
  5191 functions (useful for Hoare logic etc. with implicit dependencies);
  5192 see HOL/ex/Antiquote for an example use;
  5193 
  5194 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  5195 cterm -> thm;
  5196 
  5197 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  5198 subgoal;
  5199 
  5200 * Display.print_goals function moved to Locale.print_goals;
  5201 
  5202 * standard print function for goals supports current_goals_markers
  5203 variable for marking begin of proof, end of proof, start of goal; the
  5204 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  5205 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  5206 for example;
  5207 
  5208 
  5209 
  5210 New in Isabelle98 (January 1998)
  5211 --------------------------------
  5212 
  5213 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  5214 
  5215 * changed lexical syntax of terms / types: dots made part of long
  5216 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  5217 
  5218 * simpset (and claset) reference variable replaced by functions
  5219 simpset / simpset_ref;
  5220 
  5221 * no longer supports theory aliases (via merge) and non-trivial
  5222 implicit merge of thms' signatures;
  5223 
  5224 * most internal names of constants changed due to qualified names;
  5225 
  5226 * changed Pure/Sequence interface (see Pure/seq.ML);
  5227 
  5228 
  5229 *** General Changes ***
  5230 
  5231 * hierachically structured name spaces (for consts, types, axms, thms
  5232 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  5233 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  5234 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  5235 long_names for fully qualified output names; NOTE: ML programs
  5236 (special tactics, packages etc.) referring to internal names may have
  5237 to be adapted to cope with fully qualified names; in case of severe
  5238 backward campatibility problems try setting 'global_names' at compile
  5239 time to have enrything declared within a flat name space; one may also
  5240 fine tune name declarations in theories via the 'global' and 'local'
  5241 section;
  5242 
  5243 * reimplemented the implicit simpset and claset using the new anytype
  5244 data filed in signatures; references simpset:simpset ref etc. are
  5245 replaced by functions simpset:unit->simpset and
  5246 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  5247 to patch your ML files accordingly;
  5248 
  5249 * HTML output now includes theory graph data for display with Java
  5250 applet or isatool browser; data generated automatically via isatool
  5251 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  5252 
  5253 * defs may now be conditional; improved rewrite_goals_tac to handle
  5254 conditional equations;
  5255 
  5256 * defs now admits additional type arguments, using TYPE('a) syntax;
  5257 
  5258 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  5259 creates a new theory node; implicit merge of thms' signatures is
  5260 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  5261 transfer:theory->thm->thm in (rare) cases;
  5262 
  5263 * improved handling of draft signatures / theories; draft thms (and
  5264 ctyps, cterms) are automatically promoted to real ones;
  5265 
  5266 * slightly changed interfaces for oracles: admit many per theory, named
  5267 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  5268 
  5269 * print_goals: optional output of const types (set show_consts and
  5270 show_types);
  5271 
  5272 * improved output of warnings (###) and errors (***);
  5273 
  5274 * subgoal_tac displays a warning if the new subgoal has type variables;
  5275 
  5276 * removed old README and Makefiles;
  5277 
  5278 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  5279 
  5280 * removed obsolete init_pps and init_database;
  5281 
  5282 * deleted the obsolete tactical STATE, which was declared by
  5283     fun STATE tacfun st = tacfun st st;
  5284 
  5285 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  5286 (which abbreviates $HOME);
  5287 
  5288 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  5289 use isatool fixseq to adapt your ML programs (this works for fully
  5290 qualified references to the Sequence structure only!);
  5291 
  5292 * use_thy no longer requires writable current directory; it always
  5293 reloads .ML *and* .thy file, if either one is out of date;
  5294 
  5295 
  5296 *** Classical Reasoner ***
  5297 
  5298 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  5299 tactics that use classical reasoning to simplify a subgoal without
  5300 splitting it into several subgoals;
  5301 
  5302 * Safe_tac: like safe_tac but uses the default claset;
  5303 
  5304 
  5305 *** Simplifier ***
  5306 
  5307 * added simplification meta rules:
  5308     (asm_)(full_)simplify: simpset -> thm -> thm;
  5309 
  5310 * simplifier.ML no longer part of Pure -- has to be loaded by object
  5311 logics (again);
  5312 
  5313 * added prems argument to simplification procedures;
  5314 
  5315 * HOL, FOL, ZF: added infix function `addsplits':
  5316   instead of `<simpset> setloop (split_tac <thms>)'
  5317   you can simply write `<simpset> addsplits <thms>'
  5318 
  5319 
  5320 *** Syntax ***
  5321 
  5322 * TYPE('a) syntax for type reflection terms;
  5323 
  5324 * no longer handles consts with name "" -- declare as 'syntax' instead;
  5325 
  5326 * pretty printer: changed order of mixfix annotation preference (again!);
  5327 
  5328 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  5329 
  5330 
  5331 *** HOL ***
  5332 
  5333 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5334   with `addloop' of the simplifier to faciliate case splitting in premises.
  5335 
  5336 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  5337 
  5338 * HOL/Auth: new protocol proofs including some for the Internet
  5339   protocol TLS;
  5340 
  5341 * HOL/Map: new theory of `maps' a la VDM;
  5342 
  5343 * HOL/simplifier: simplification procedures nat_cancel_sums for
  5344 cancelling out common nat summands from =, <, <= (in)equalities, or
  5345 differences; simplification procedures nat_cancel_factor for
  5346 cancelling common factor from =, <, <= (in)equalities over natural
  5347 sums; nat_cancel contains both kinds of procedures, it is installed by
  5348 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  5349 
  5350 * HOL/simplifier: terms of the form
  5351   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  5352   are rewritten to
  5353   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  5354   and those of the form
  5355   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  5356   are rewritten to
  5357   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  5358 
  5359 * HOL/datatype
  5360   Each datatype `t' now comes with a theorem `split_t_case' of the form
  5361 
  5362   P(t_case f1 ... fn x) =
  5363      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  5364         ...
  5365        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  5366      )
  5367 
  5368   and a theorem `split_t_case_asm' of the form
  5369 
  5370   P(t_case f1 ... fn x) =
  5371     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  5372         ...
  5373        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  5374      )
  5375   which can be added to a simpset via `addsplits'. The existing theorems
  5376   expand_list_case and expand_option_case have been renamed to
  5377   split_list_case and split_option_case.
  5378 
  5379 * HOL/Arithmetic:
  5380   - `pred n' is automatically converted to `n-1'.
  5381     Users are strongly encouraged not to use `pred' any longer,
  5382     because it will disappear altogether at some point.
  5383   - Users are strongly encouraged to write "0 < n" rather than
  5384     "n ~= 0". Theorems and proof tools have been modified towards this
  5385     `standard'.
  5386 
  5387 * HOL/Lists:
  5388   the function "set_of_list" has been renamed "set" (and its theorems too);
  5389   the function "nth" now takes its arguments in the reverse order and
  5390   has acquired the infix notation "!" as in "xs!n".
  5391 
  5392 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  5393 
  5394 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  5395   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  5396 
  5397 * HOL/record: extensible records with schematic structural subtyping
  5398 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  5399 still lacks various theorems and concrete record syntax;
  5400 
  5401 
  5402 *** HOLCF ***
  5403 
  5404 * removed "axioms" and "generated by" sections;
  5405 
  5406 * replaced "ops" section by extended "consts" section, which is capable of
  5407   handling the continuous function space "->" directly;
  5408 
  5409 * domain package:
  5410   . proves theorems immediately and stores them in the theory,
  5411   . creates hierachical name space,
  5412   . now uses normal mixfix annotations (instead of cinfix...),
  5413   . minor changes to some names and values (for consistency),
  5414   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  5415   . separator between mutual domain defs: changed "," to "and",
  5416   . improved handling of sort constraints;  now they have to
  5417     appear on the left-hand side of the equations only;
  5418 
  5419 * fixed LAM <x,y,zs>.b syntax;
  5420 
  5421 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  5422 adm (%x. P (t x)), where P is chainfinite and t continuous;
  5423 
  5424 
  5425 *** FOL and ZF ***
  5426 
  5427 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  5428   with `addloop' of the simplifier to faciliate case splitting in premises.
  5429 
  5430 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  5431 in HOL, they strip ALL and --> from proved theorems;
  5432 
  5433 
  5434 
  5435 New in Isabelle94-8 (May 1997)
  5436 ------------------------------
  5437 
  5438 *** General Changes ***
  5439 
  5440 * new utilities to build / run / maintain Isabelle etc. (in parts
  5441 still somewhat experimental); old Makefiles etc. still functional;
  5442 
  5443 * new 'Isabelle System Manual';
  5444 
  5445 * INSTALL text, together with ./configure and ./build scripts;
  5446 
  5447 * reimplemented type inference for greater efficiency, better error
  5448 messages and clean internal interface;
  5449 
  5450 * prlim command for dealing with lots of subgoals (an easier way of
  5451 setting goals_limit);
  5452 
  5453 
  5454 *** Syntax ***
  5455 
  5456 * supports alternative (named) syntax tables (parser and pretty
  5457 printer); internal interface is provided by add_modesyntax(_i);
  5458 
  5459 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  5460 be used in conjunction with the Isabelle symbol font; uses the
  5461 "symbols" syntax table;
  5462 
  5463 * added token_translation interface (may translate name tokens in
  5464 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  5465 the current print_mode); IMPORTANT: user print translation functions
  5466 are responsible for marking newly introduced bounds
  5467 (Syntax.mark_boundT);
  5468 
  5469 * token translations for modes "xterm" and "xterm_color" that display
  5470 names in bold, underline etc. or colors (which requires a color
  5471 version of xterm);
  5472 
  5473 * infixes may now be declared with names independent of their syntax;
  5474 
  5475 * added typed_print_translation (like print_translation, but may
  5476 access type of constant);
  5477 
  5478 
  5479 *** Classical Reasoner ***
  5480 
  5481 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  5482 some limitations.  Blast_tac...
  5483   + ignores addss, addbefore, addafter; this restriction is intrinsic
  5484   + ignores elimination rules that don't have the correct format
  5485         (the conclusion MUST be a formula variable)
  5486   + ignores types, which can make HOL proofs fail
  5487   + rules must not require higher-order unification, e.g. apply_type in ZF
  5488     [message "Function Var's argument not a bound variable" relates to this]
  5489   + its proof strategy is more general but can actually be slower
  5490 
  5491 * substitution with equality assumptions no longer permutes other
  5492 assumptions;
  5493 
  5494 * minor changes in semantics of addafter (now called addaltern); renamed
  5495 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  5496 (and access functions for it);
  5497 
  5498 * improved combination of classical reasoner and simplifier:
  5499   + functions for handling clasimpsets
  5500   + improvement of addss: now the simplifier is called _after_ the
  5501     safe steps.
  5502   + safe variant of addss called addSss: uses safe simplifications
  5503     _during_ the safe steps. It is more complete as it allows multiple
  5504     instantiations of unknowns (e.g. with slow_tac).
  5505 
  5506 *** Simplifier ***
  5507 
  5508 * added interface for simplification procedures (functions that
  5509 produce *proven* rewrite rules on the fly, depending on current
  5510 redex);
  5511 
  5512 * ordering on terms as parameter (used for ordered rewriting);
  5513 
  5514 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  5515 
  5516 * the solver is now split into a safe and an unsafe part.
  5517 This should be invisible for the normal user, except that the
  5518 functions setsolver and addsolver have been renamed to setSolver and
  5519 addSolver; added safe_asm_full_simp_tac;
  5520 
  5521 
  5522 *** HOL ***
  5523 
  5524 * a generic induction tactic `induct_tac' which works for all datatypes and
  5525 also for type `nat';
  5526 
  5527 * a generic case distinction tactic `exhaust_tac' which works for all
  5528 datatypes and also for type `nat';
  5529 
  5530 * each datatype comes with a function `size';
  5531 
  5532 * patterns in case expressions allow tuple patterns as arguments to
  5533 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  5534 
  5535 * primrec now also works with type nat;
  5536 
  5537 * recdef: a new declaration form, allows general recursive functions to be
  5538 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  5539 
  5540 * the constant for negation has been renamed from "not" to "Not" to
  5541 harmonize with FOL, ZF, LK, etc.;
  5542 
  5543 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  5544 infinite lists;
  5545 
  5546 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  5547 
  5548 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  5549 problems in commutative rings, using axiomatic type classes for + and *;
  5550 
  5551 * more examples in HOL/MiniML and HOL/Auth;
  5552 
  5553 * more default rewrite rules for quantifiers, union/intersection;
  5554 
  5555 * a new constant `arbitrary == @x.False';
  5556 
  5557 * HOLCF/IOA replaces old HOL/IOA;
  5558 
  5559 * HOLCF changes: derived all rules and arities
  5560   + axiomatic type classes instead of classes
  5561   + typedef instead of faking type definitions
  5562   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  5563   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  5564   + eliminated the types void, one, tr
  5565   + use unit lift and bool lift (with translations) instead of one and tr
  5566   + eliminated blift from Lift3.thy (use Def instead of blift)
  5567   all eliminated rules are derived as theorems --> no visible changes ;
  5568 
  5569 
  5570 *** ZF ***
  5571 
  5572 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  5573 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  5574 as ZF_cs addSIs [equalityI];
  5575 
  5576 
  5577 
  5578 New in Isabelle94-7 (November 96)
  5579 ---------------------------------
  5580 
  5581 * allowing negative levels (as offsets) in prlev and choplev;
  5582 
  5583 * super-linear speedup for large simplifications;
  5584 
  5585 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  5586 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  5587 FAIL); can suppress it using the command Delsimps (ex_simps @
  5588 all_simps); De Morgan laws are also now included, by default;
  5589 
  5590 * improved printing of ==>  :  ~:
  5591 
  5592 * new object-logic "Sequents" adds linear logic, while replacing LK
  5593 and Modal (thanks to Sara Kalvala);
  5594 
  5595 * HOL/Auth: correctness proofs for authentication protocols;
  5596 
  5597 * HOL: new auto_tac combines rewriting and classical reasoning (many
  5598 examples on HOL/Auth);
  5599 
  5600 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  5601 the rewriter and classical reasoner simultaneously;
  5602 
  5603 * function uresult no longer returns theorems in "standard" format;
  5604 regain previous version by: val uresult = standard o uresult;
  5605 
  5606 
  5607 
  5608 New in Isabelle94-6
  5609 -------------------
  5610 
  5611 * oracles -- these establish an interface between Isabelle and trusted
  5612 external reasoners, which may deliver results as theorems;
  5613 
  5614 * proof objects (in particular record all uses of oracles);
  5615 
  5616 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  5617 
  5618 * "constdefs" section in theory files;
  5619 
  5620 * "primrec" section (HOL) no longer requires names;
  5621 
  5622 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  5623 
  5624 
  5625 
  5626 New in Isabelle94-5
  5627 -------------------
  5628 
  5629 * reduced space requirements;
  5630 
  5631 * automatic HTML generation from theories;
  5632 
  5633 * theory files no longer require "..." (quotes) around most types;
  5634 
  5635 * new examples, including two proofs of the Church-Rosser theorem;
  5636 
  5637 * non-curried (1994) version of HOL is no longer distributed;
  5638 
  5639 
  5640 
  5641 New in Isabelle94-4
  5642 -------------------
  5643 
  5644 * greatly reduced space requirements;
  5645 
  5646 * theory files (.thy) no longer require \...\ escapes at line breaks;
  5647 
  5648 * searchable theorem database (see the section "Retrieving theorems" on
  5649 page 8 of the Reference Manual);
  5650 
  5651 * new examples, including Grabczewski's monumental case study of the
  5652 Axiom of Choice;
  5653 
  5654 * The previous version of HOL renamed to Old_HOL;
  5655 
  5656 * The new version of HOL (previously called CHOL) uses a curried syntax
  5657 for functions.  Application looks like f a b instead of f(a,b);
  5658 
  5659 * Mutually recursive inductive definitions finally work in HOL;
  5660 
  5661 * In ZF, pattern-matching on tuples is now available in all abstractions and
  5662 translates to the operator "split";
  5663 
  5664 
  5665 
  5666 New in Isabelle94-3
  5667 -------------------
  5668 
  5669 * new infix operator, addss, allowing the classical reasoner to
  5670 perform simplification at each step of its search.  Example:
  5671         fast_tac (cs addss ss)
  5672 
  5673 * a new logic, CHOL, the same as HOL, but with a curried syntax
  5674 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  5675 look like (a,b) instead of <a,b>;
  5676 
  5677 * PLEASE NOTE: CHOL will eventually replace HOL!
  5678 
  5679 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  5680 It translates to the operator "split".  A new theory of integers is available;
  5681 
  5682 * In ZF, integer numerals now denote two's-complement binary integers.
  5683 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  5684 
  5685 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  5686 of the Axiom of Choice;
  5687 
  5688 
  5689 
  5690 New in Isabelle94-2
  5691 -------------------
  5692 
  5693 * Significantly faster resolution;
  5694 
  5695 * the different sections in a .thy file can now be mixed and repeated
  5696 freely;
  5697 
  5698 * Database of theorems for FOL, HOL and ZF.  New
  5699 commands including qed, qed_goal and bind_thm store theorems in the database.
  5700 
  5701 * Simple database queries: return a named theorem (get_thm) or all theorems of
  5702 a given theory (thms_of), or find out what theory a theorem was proved in
  5703 (theory_of_thm);
  5704 
  5705 * Bugs fixed in the inductive definition and datatype packages;
  5706 
  5707 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  5708 and HOL_dup_cs obsolete;
  5709 
  5710 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  5711 have been removed;
  5712 
  5713 * Simpler definition of function space in ZF;
  5714 
  5715 * new results about cardinal and ordinal arithmetic in ZF;
  5716 
  5717 * 'subtype' facility in HOL for introducing new types as subsets of existing
  5718 types;
  5719 
  5720 :mode=text:wrap=hard:maxLineLen=72:
  5721 
  5722 
  5723 $Id$