2 Isabelle NEWS -- history user-relevant changes
3 ==============================================
5 New in Isabelle2001 (?? 2001)
6 -----------------------------
8 *** Document preparation ***
10 * greatly simplified document preparation setup, including more
11 graceful interpretation of isatool usedir -i/-d/-D options, and more
12 instructive isatool mkdir; users should basically be able to get
13 started with "isatool mkdir Test && isatool make";
15 * theory dependency graph may now be incorporated into documents;
16 isatool usedir -g true will produce session_graph.eps/.pdf for use
17 with \includegraphics of LaTeX;
19 * proper spacing of consecutive markup elements, especially text
20 blocks after section headings;
22 * support bold style (for single symbols only), input syntax is like
23 this: "\<^bold>\<alpha>" or "\<^bold>A";
25 * \<bullet> is now output as bold \cdot by default, which looks much
26 better in printed text;
28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
29 note that these symbols are currently unavailable in Proof General /
35 * Pure/Provers: improved proof by cases and induction;
36 - 'case' command admits impromptu naming of parameters (such as
38 - 'induct' method divinates rule instantiation from the inductive
39 claim; no longer requires excessive ?P bindings for proper
40 instantiation of cases;
41 - 'induct' method properly enumerates all possibilities of set/type
42 rules; as a consequence facts may be also passed through *type*
43 rules without further ado;
44 - 'induct' method now derives symbolic cases from the *rulified*
45 rule (before it used to rulify cases stemming from the internal
46 atomized version); this means that the context of a non-atomic
47 statement becomes is included in the hypothesis, avoiding the
48 slightly cumbersome show "PROP ?case" form;
49 - 'induct' may now use elim-style induction rules without chaining
50 facts, using ``missing'' premises from the goal state; this allows
51 rules stemming from inductive sets to be applied in unstructured
52 scripts, while still benefitting from proper handling of non-atomic
53 statements; NB: major inductive premises need to be put first, all
54 the rest of the goal is passed through the induction;
55 - 'induct' proper support for mutual induction involving non-atomic
56 rule statements (uses the new concept of simultaneous goals, see
58 - removed obsolete "(simplified)" and "(stripped)" options of methods;
59 - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
60 - moved induct/cases attributes to Pure, methods to Provers;
61 - generic method setup instantiated for FOL and HOL;
63 * Pure: support multiple simultaneous goal statements, for example
64 "have a: A and b: B" (same for 'theorem' etc.); being a pure
65 meta-level mechanism, this acts as if several individual goals had
66 been stated separately; in particular common proof methods need to be
67 repeated in order to cover all claims; note that a single elimination
68 step is *not* sufficient to establish the two conjunctions, so this
71 assume "A & B" then have A and B .. (*".." fails*)
73 better use "obtain" in situations as above; alternative refer to
74 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
76 * Pure: proper integration with ``locales''; unlike the original
77 version by Florian Kammüller, Isar locales package high-level proof
78 contexts rather than raw logical ones (e.g. we admit to include
79 attributes everywhere); operations on locales include merge and
80 rename; e.g. see HOL/ex/Locales.thy;
82 * Pure: theory goals now support ad-hoc contexts, which are discharged
83 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
84 coincides with that of a locale body;
86 * Pure: renamed "antecedent" case to "rule_context";
88 * Pure: added 'corollary' command;
90 * Pure: fixed 'token_translation' command;
92 * Pure: removed obsolete 'exported' attribute;
94 * Pure: dummy pattern "_" in is/let is now automatically lifted over
95 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
96 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
98 * Pure: method 'atomize' presents local goal premises as object-level
99 statements (atomic meta-level propositions); setup controlled via
100 rewrite rules declarations of 'atomize' attribute; example
101 application: 'induct' method with proper rule statements in improper
104 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
105 now consider the syntactic context of assumptions, giving a better
106 chance to get type-inference of the arguments right (this is
107 especially important for locales);
109 * Pure: "sorry" no longer requires quick_and_dirty in interactive
112 * Pure/obtain: the formal conclusion "thesis", being marked as
113 ``internal'', may no longer be reference directly in the text;
114 potential INCOMPATIBILITY, may need to use "?thesis" in rare
117 * Pure: generic 'sym' attribute which declares a rule both as pure
118 'elim?' and for the 'symmetric' operation;
120 * Pure/Provers/classical: simplified integration with pure rule
121 attributes and methods; the classical "intro?/elim?/dest?"
122 declarations coincide with the pure ones; the "rule" method no longer
123 includes classically swapped intros; "intro" and "elim" methods no
124 longer pick rules from the context; also got rid of ML declarations
125 AddXIs/AddXEs/AddXDs; all of this has some potential for
128 * Provers/classical: attribute 'swapped' produces classical inversions
129 of introduction rules;
131 * Provers/simplifier: 'simplified' attribute may refer to explicit
132 rules instead of full simplifier context; 'iff' attribute handles
135 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
137 * HOL: 'recdef' now fails on unfinished automated proofs, use
138 "(permissive)" option to recover old behavior;
140 * HOL: 'inductive' no longer features separate (collective) attributes
141 for 'intros' (was found too confusing);
143 * HOL: properly declared induction rules less_induct and
146 * HOLCF: domain package adapted to new-style theories, e.g. see
149 * ZF: proper integration of logic-specific tools and packages,
150 including theory commands '(co)inductive', '(co)datatype',
151 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
152 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
158 * HOL: moved over to sane numeral syntax; the new policy is as
161 - 0 and 1 are polymorphic constants, which are defined on any
162 numeric type (nat, int, real etc.);
164 - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
165 binary representation internally;
167 - type nat has special constructor Suc, and generally prefers Suc 0
168 over 1::nat and Suc (Suc 0) over 2::nat;
170 This change may cause significant problems of INCOMPATIBILITY; here
171 are some hints on converting existing sources:
173 - due to the new "num" token, "-0" and "-1" etc. are now atomic
174 entities, so expressions involving "-" (unary or binary minus) need
175 to be spaced properly;
177 - existing occurrences of "1" may need to be constraint "1::nat" or
178 even replaced by Suc 0; similar for old "2";
180 - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
182 - remove all special provisions on numerals in proofs;
184 * HOL: the class of all HOL types is now called "type" rather than
185 "term"; INCOMPATIBILITY, need to adapt references to this type class
186 in axclass/classes, instance/arities, and (usually rare) occurrences
187 in typings (of consts etc.); internally the class is called
188 "HOL.type", ML programs should refer to HOLogic.typeS;
190 * HOL/record package improvements:
191 - new derived operations "fields" to build a partial record section,
192 "extend" to promote a fixed record to a record scheme, and
193 "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
194 declared as simp by default;
195 - removed "make_scheme" operations (use "make" with "extend") --
197 - removed "more" class (simply use "term") -- INCOMPATIBILITY;
198 - provides cases/induct rules for use with corresponding Isar
199 methods (for concrete records, record schemes, concrete more
200 parts, and schematic more parts -- in that order);
201 - internal definitions directly based on a light-weight abstract
202 theory of product types over typedef rather than datatype;
204 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
206 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
207 (beware of argument permutation!);
209 * HOL: linorder_less_split superseded by linorder_cases;
211 * HOL: added "The" definite description operator; move Hilbert's "Eps"
212 to peripheral theory "Hilbert_Choice";
214 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
215 in this (rare) case use:
217 delSWrapper "split_all_tac"
218 addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
220 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
223 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
224 Isabelle's type classes, ^ on functions and relations has too general
225 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
226 necessary to attach explicit type constraints;
228 * HOL: syntax translations now work properly with numerals and records
231 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
234 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
235 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
236 renamed "Product_Type.unit";
241 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
242 potential INCOMPATIBILITY; now use plain induct_tac instead of former
243 lift.induct_tac, always use UU instead of Undef;
248 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
249 typeless version of the formalism;
251 * ZF/Induct: new directory for examples of inductive definitions,
252 including theory Multiset for multiset orderings;
254 * ZF: the integer library now covers quotients and remainders, with
255 many laws relating division to addition, multiplication, etc.;
260 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
261 variable proof controls level of detail: 0 = no proofs (only oracle
262 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
263 also ref manual for further ML interfaces;
265 * Pure/axclass: removed obsolete ML interface
266 goal_subclass/goal_arity;
268 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
269 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
270 separate tokens, so expressions involving minus need to be spaced
273 * Pure/syntax: support non-oriented infixes, using keyword "infix"
274 rather than "infixl" or "infixr";
276 * Pure/syntax: concrete syntax for dummy type variables admits genuine
277 sort constraint specifications in type inference; e.g. "x::_::foo"
278 ensures that the type of "x" is of sort "foo" (but not necessarily a
281 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
282 control output of nested => (types); the default behavior is
285 * Pure/syntax: builtin parse translation for "_constify" turns valued
286 tokens into AST constants;
288 * Pure/syntax: prefer later declarations of translations and print
289 translation functions; potential INCOMPATIBILITY: need to reverse
290 multiple declarations for same syntax element constant;
292 * Provers/classical: renamed addaltern to addafter, addSaltern to
295 * Provers/clasimp: ``iff'' declarations now handle conditional rules
298 * system: refrain from any attempt at filtering input streams; no
299 longer support ``8bit'' encoding of old isabelle font, instead proper
300 iso-latin characters may now be used;
302 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
304 * system: Proof General keywords specification is now part of the
305 Isabelle distribution (see etc/isar-keywords.el);
307 * system: smart selection of Isabelle process versus Isabelle
308 interface, accommodates case-insensitive file systems (e.g. HFS+); may
309 run both "isabelle" and "Isabelle" even if file names are badly
310 damaged (executable inspects the case of the first letter of its own
311 name); added separate "isabelle-process" and "isabelle-interface";
315 New in Isabelle99-2 (February 2001)
316 -----------------------------------
318 *** Overview of INCOMPATIBILITIES ***
320 * HOL: please note that theories in the Library and elsewhere often use the
321 new-style (Isar) format; to refer to their theorems in an ML script you must
322 bind them to ML identifers by e.g. val thm_name = thm "thm_name";
324 * HOL: inductive package no longer splits induction rule aggressively,
325 but only as far as specified by the introductions given; the old
326 format may be recovered via ML function complete_split_rule or attribute
327 'split_rule (complete)';
329 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
330 gfp_Tarski to gfp_unfold;
332 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
334 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
335 relation); infix "^^" has been renamed "``"; infix "``" has been
336 renamed "`"; "univalent" has been renamed "single_valued";
338 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
341 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
343 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
345 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
346 consequence, it is no longer monotonic wrt. the local goal context
347 (which is now passed through the inductive cases);
349 * Document preparation: renamed standard symbols \<ll> to \<lless> and
350 \<gg> to \<ggreater>;
353 *** Document preparation ***
355 * \isabellestyle{NAME} selects version of Isabelle output (currently
356 available: are "it" for near math-mode best-style output, "sl" for
357 slanted text style, and "tt" for plain type-writer; if no
358 \isabellestyle command is given, output is according to slanted
361 * support sub/super scripts (for single symbols only), input syntax is
362 like this: "A\<^sup>*" or "A\<^sup>\<star>";
364 * some more standard symbols; see Appendix A of the system manual for
365 the complete list of symbols defined in isabellesym.sty;
367 * improved isabelle style files; more abstract symbol implementation
368 (should now use \isamath{...} and \isatext{...} in custom symbol
371 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
372 state; Note that presentation of goal states does not conform to
373 actual human-readable proof documents. Please do not include goal
374 states into document output unless you really know what you are doing!
376 * proper indentation of antiquoted output with proportional LaTeX
379 * no_document ML operator temporarily disables LaTeX document
382 * isatool unsymbolize tunes sources for plain ASCII communication;
387 * Pure: Isar now suffers initial goal statements to contain unbound
388 schematic variables (this does not conform to actual readable proof
389 documents, due to unpredictable outcome and non-compositional proof
390 checking); users who know what they are doing may use schematic goals
391 for Prolog-style synthesis of proven results;
393 * Pure: assumption method (an implicit finishing) now handles actual
396 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
397 initial goal, declare "that" only as Pure intro (only for single
398 steps); the "that" rule assumption may now be involved in implicit
399 finishing, thus ".." becomes a feasible for trivial obtains;
401 * Pure: default proof step now includes 'intro_classes'; thus trivial
402 instance proofs may be performed by "..";
404 * Pure: ?thesis / ?this / "..." now work for pure meta-level
407 * Pure: more robust selection of calculational rules;
409 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
410 rule (as well as the assumption rule);
412 * Pure: 'thm_deps' command visualizes dependencies of theorems and
413 lemmas, using the graph browser tool;
415 * Pure: predict failure of "show" in interactive mode;
417 * Pure: 'thms_containing' now takes actual terms as arguments;
419 * HOL: improved method 'induct' --- now handles non-atomic goals
420 (potential INCOMPATIBILITY); tuned error handling;
422 * HOL: cases and induct rules now provide explicit hints about the
423 number of facts to be consumed (0 for "type" and 1 for "set" rules);
424 any remaining facts are inserted into the goal verbatim;
426 * HOL: local contexts (aka cases) may now contain term bindings as
427 well; the 'cases' and 'induct' methods new provide a ?case binding for
428 the result to be shown in each case;
430 * HOL: added 'recdef_tc' command;
432 * isatool convert assists in eliminating legacy ML scripts;
437 * HOL/Library: a collection of generic theories to be used together
438 with main HOL; the theory loader path already includes this directory
439 by default; the following existing theories have been moved here:
440 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
441 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
443 * HOL/Unix: "Some aspects of Unix file-system security", a typical
444 modelling and verification task performed in Isabelle/HOL +
445 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
447 * HOL/Algebra: special summation operator SUM no longer exists, it has
448 been replaced by setsum; infix 'assoc' now has priority 50 (like
449 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
450 'domain', this makes the theory consistent with mathematical
453 * HOL basics: added overloaded operations "inverse" and "divide"
454 (infix "/"), syntax for generic "abs" operation, generic summation
457 * HOL/typedef: simplified package, provide more useful rules (see also
460 * HOL/datatype: induction rule for arbitrarily branching datatypes is
461 now expressed as a proper nested rule (old-style tactic scripts may
462 require atomize_strip_tac to cope with non-atomic premises);
464 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
465 to "split_conv" (old name still available for compatibility);
467 * HOL: improved concrete syntax for strings (e.g. allows translation
468 rules with string literals);
470 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
471 and Fleuriot's mechanization of analysis, including the transcendental
472 functions for the reals;
474 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
479 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
480 "lam" is displayed as TWO lambda-symbols
482 * CTT: theory Main now available, containing everything (that is, Bool
488 * Pure: the Simplifier has been implemented properly as a derived rule
489 outside of the actual kernel (at last!); the overall performance
490 penalty in practical applications is about 50%, while reliability of
491 the Isabelle inference kernel has been greatly improved;
493 * print modes "brackets" and "no_brackets" control output of nested =>
494 (types) and ==> (props); the default behaviour is "brackets";
496 * Provers: fast_tac (and friends) now handle actual object-logic rules
497 as assumptions as well;
499 * system: support Poly/ML 4.0;
501 * system: isatool install handles KDE version 1 or 2;
505 New in Isabelle99-1 (October 2000)
506 ----------------------------------
508 *** Overview of INCOMPATIBILITIES ***
510 * HOL: simplification of natural numbers is much changed; to partly
511 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
512 issue the following ML commands:
514 Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
515 Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
517 * HOL: simplification no longer dives into case-expressions; this is
518 controlled by "t.weak_case_cong" for each datatype t;
520 * HOL: nat_less_induct renamed to less_induct;
522 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
523 fixsome to patch .thy and .ML sources automatically;
525 select_equality -> some_equality
526 select_eq_Ex -> some_eq_ex
527 selectI2EX -> someI2_ex
530 select1_equality -> some1_equality
531 Eps_sym_eq -> some_sym_eq_trivial
532 Eps_eq -> some_eq_trivial
534 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
536 * HOL: removed obsolete theorem binding expand_if (refer to split_if
539 * HOL: the recursion equations generated by 'recdef' are now called
540 f.simps instead of f.rules;
542 * HOL: qed_spec_mp now also handles bounded ALL as well;
544 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
547 * HOL: the constant for "f``x" is now "image" rather than "op ``";
549 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
551 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
552 product is now "<*>" instead of "Times"; the lexicographic product is
553 now "<*lex*>" instead of "**";
555 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
556 of main HOL, but was unused); better use HOL's datatype package;
558 * HOL: removed "symbols" syntax for constant "override" of theory Map;
559 the old syntax may be recovered as follows:
562 override :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
563 (infixl "\\<oplus>" 100)
565 * HOL/Real: "rabs" replaced by overloaded "abs" function;
567 * HOL/ML: even fewer consts are declared as global (see theories Ord,
568 Lfp, Gfp, WF); this only affects ML packages that refer to const names
571 * HOL and ZF: syntax for quotienting wrt an equivalence relation
572 changed from A/r to A//r;
574 * ZF: new treatment of arithmetic (nat & int) may break some old
577 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
578 rulify -> rule_format, elimify -> elim_format, ...);
580 * Isar/Provers: intro/elim/dest attributes changed; renamed
581 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
582 should have to change intro!! to intro? only); replaced "delrule" by
585 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
587 * Provers: strengthened force_tac by using new first_best_tac;
589 * LaTeX document preparation: several changes of isabelle.sty (see
593 *** Document preparation ***
595 * formal comments (text blocks etc.) in new-style theories may now
596 contain antiquotations of thm/prop/term/typ/text to be presented
597 according to latex print mode; concrete syntax is like this:
598 @{term[show_types] "f(x) = a + x"};
600 * isatool mkdir provides easy setup of Isabelle session directories,
601 including proper document sources;
603 * generated LaTeX sources are now deleted after successful run
604 (isatool document -c); may retain a copy somewhere else via -D option
607 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
608 style files, achieving self-contained LaTeX sources and simplifying
611 * old-style theories now produce (crude) LaTeX output as well;
613 * browser info session directories are now self-contained (may be put
614 on WWW server seperately); improved graphs of nested sessions; removed
615 graph for 'all sessions';
617 * several improvements in isabelle style files; \isabellestyle{it}
618 produces fake math mode output; \isamarkupheader is now \section by
619 default; see lib/texinputs/isabelle.sty etc.;
624 * Isar/Pure: local results and corresponding term bindings are now
625 subject to Hindley-Milner polymorphism (similar to ML); this
626 accommodates incremental type-inference very nicely;
628 * Isar/Pure: new derived language element 'obtain' supports
629 generalized existence reasoning;
631 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
632 support accumulation of results, without applying any rules yet;
633 useful to collect intermediate results without explicit name
634 references, and for use with transitivity rules with more than 2
637 * Isar/Pure: scalable support for case-analysis type proofs: new
638 'case' language element refers to local contexts symbolically, as
639 produced by certain proof methods; internally, case names are attached
640 to theorems as "tags";
642 * Isar/Pure: theory command 'hide' removes declarations from
643 class/type/const name spaces;
645 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
646 indicate potential overloading;
648 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
650 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
651 "{a,b,c}" instead of {a,b,c};
653 * Isar/Pure now provides its own version of intro/elim/dest
654 attributes; useful for building new logics, but beware of confusion
655 with the version in Provers/classical;
657 * Isar/Pure: the local context of (non-atomic) goals is provided via
658 case name 'antecedent';
660 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
661 to the current context is now done automatically);
663 * Isar/Pure: theory command 'method_setup' provides a simple interface
664 for definining proof methods in ML;
666 * Isar/Provers: intro/elim/dest attributes changed; renamed
667 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
668 most cases, one should have to change intro!! to intro? only);
669 replaced "delrule" by "rule del";
671 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
672 'symmetric' attribute (the latter supercedes [RS sym]);
674 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
675 method modifier); 'simp' method: 'only:' modifier removes loopers as
676 well (including splits);
678 * Isar/Provers: Simplifier and Classical methods now support all kind
679 of modifiers used in the past, including 'cong', 'iff', etc.
681 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
682 of Simplifier and Classical reasoner);
684 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
685 now support named cases; major packages (inductive, datatype, primrec,
686 recdef) support case names and properly name parameters;
688 * Isar/HOL: new transitivity rules for substitution in inequalities --
689 monotonicity conditions are extracted to be proven at end of
692 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
695 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
696 split_if split_if_asm; datatype package provides theorems foo.splits =
697 foo.split foo.split_asm for each datatype;
699 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
700 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
701 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
702 use "(cases (simplified))" method in proper proof texts);
704 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
706 * Isar: names of theorems etc. may be natural numbers as well;
708 * Isar: 'pr' command: optional arguments for goals_limit and
709 ProofContext.prems_limit; no longer prints theory contexts, but only
712 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
713 additional print modes to be specified; e.g. "pr(latex)" will print
714 proof state according to the Isabelle LaTeX style;
716 * Isar: improved support for emulating tactic scripts, including proof
717 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
718 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
721 * Isar: simplified (more robust) goal selection of proof methods: 1st
722 goal, all goals, or explicit goal specifier (tactic emulation); thus
723 'proof method scripts' have to be in depth-first order;
725 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
727 * Isar: removed 'help' command, which hasn't been too helpful anyway;
728 should instead use individual commands for printing items
729 (print_commands, print_methods etc.);
731 * Isar: added 'nothing' --- the empty list of theorems;
736 * HOL/MicroJava: formalization of a fragment of Java, together with a
737 corresponding virtual machine and a specification of its bytecode
738 verifier and a lightweight bytecode verifier, including proofs of
739 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
740 Cornelia Pusch (see also the homepage of project Bali at
741 http://isabelle.in.tum.de/Bali/);
743 * HOL/Algebra: new theory of rings and univariate polynomials, by
746 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
747 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
750 * HOL/Lattice: fundamental concepts of lattice theory and order
751 structures, including duals, properties of bounds versus algebraic
752 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
753 Theorem for complete lattices etc.; may also serve as a demonstration
754 for abstract algebraic reasoning using axiomatic type classes, and
755 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
757 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
760 * HOL/IMPP: extension of IMP with local variables and mutually
761 recursive procedures, by David von Oheimb;
763 * HOL/Lambda: converted into new-style theory and document;
765 * HOL/ex/Multiquote: example of multiple nested quotations and
766 anti-quotations -- basically a generalized version of de-Bruijn
767 representation; very useful in avoiding lifting of operations;
769 * HOL/record: added general record equality rule to simpset; fixed
770 select-update simplification procedure to handle extended records as
771 well; admit "r" as field name;
773 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
774 other numeric types and also as the identity of groups, rings, etc.;
776 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
777 Types nat and int belong to this axclass;
779 * HOL: greatly improved simplification involving numerals of type nat, int, real:
780 (i + #8 + j) = Suc k simplifies to #7 + (i + j) = k
781 i*j + k + j*#3*i simplifies to #4*(i*j) + k
782 two terms #m*u and #n*u are replaced by #(m+n)*u
783 (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
784 and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
785 or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
787 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
788 powerful prover for predicate logic but knows nothing of clasets; see
789 ex/mesontest.ML and ex/mesontest2.ML for example applications;
791 * HOL: new version of "case_tac" subsumes both boolean case split and
792 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
793 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
795 * HOL: simplification no longer dives into case-expressions: only the
796 selector expression is simplified, but not the remaining arms; to
797 enable full simplification of case-expressions for datatype t, you may
798 remove t.weak_case_cong from the simpset, either globally (Delcongs
799 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
801 * HOL/recdef: the recursion equations generated by 'recdef' for
802 function 'f' are now called f.simps instead of f.rules; if all
803 termination conditions are proved automatically, these simplification
804 rules are added to the simpset, as in primrec; rules may be named
805 individually as well, resulting in a separate list of theorems for
808 * HOL/While is a new theory that provides a while-combinator. It
809 permits the definition of tail-recursive functions without the
810 provision of a termination measure. The latter is necessary once the
811 invariant proof rule for while is applied.
813 * HOL: new (overloaded) notation for the set of elements below/above
814 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
816 * HOL: theorems impI, allI, ballI bound as "strip";
818 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
819 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
820 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
822 * HOL/Real: "rabs" replaced by overloaded "abs" function;
824 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
825 main HOL, but was unused);
827 * HOL: fewer consts declared as global (e.g. have to refer to
828 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
830 * HOL: tuned AST representation of nested pairs, avoiding bogus output
831 in case of overlap with user translations (e.g. judgements over
832 tuples); (note that the underlying logical represenation is still
838 * ZF: simplification automatically cancels common terms in arithmetic
839 expressions over nat and int;
841 * ZF: new treatment of nat to minimize type-checking: all operators
842 coerce their operands to a natural number using the function natify,
843 making the algebraic laws unconditional;
845 * ZF: as above, for int: operators coerce their operands to an integer
846 using the function intify;
848 * ZF: the integer library now contains many of the usual laws for the
849 orderings, including $<=, and monotonicity laws for $+ and $*;
851 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
854 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
855 to the simplifier and classical reasoner simultaneously;
860 * Provers: blast_tac now handles actual object-logic rules as
861 assumptions; note that auto_tac uses blast_tac internally as well;
863 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
864 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
866 * Provers: delrules now handles destruct rules as well (no longer need
869 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
870 [| inj ?f; ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
871 use instead the strong form,
872 [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
873 in HOL, FOL and ZF the function cla_make_elim will create such rules
876 * Provers: Simplifier.easy_setup provides a fast path to basic
877 Simplifier setup for new object-logics;
879 * Pure: AST translation rules no longer require constant head on LHS;
881 * Pure: improved name spaces: ambiguous output is qualified; support
884 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
885 XSYMBOL_HOME; no longer need to do manual configuration in most
888 * system: compression of ML heaps images may now be controlled via -c
889 option of isabelle and isatool usedir (currently only observed by
892 * system: isatool installfonts may handle X-Symbol fonts as well (very
893 useful for remote X11);
895 * system: provide TAGS file for Isabelle sources;
897 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
900 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
901 timing flag supersedes proof_timing and Toplevel.trace;
903 * ML: new combinators |>> and |>>> for incremental transformations
904 with secondary results (e.g. certain theory extensions):
906 * ML: PureThy.add_defs gets additional argument to indicate potential
907 overloading (usually false);
909 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
914 New in Isabelle99 (October 1999)
915 --------------------------------
917 *** Overview of INCOMPATIBILITIES (see below for more details) ***
919 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
920 are no longer simplified. (This allows the simplifier to unfold recursive
921 functional programs.) To restore the old behaviour, declare
923 Delcongs [if_weak_cong];
925 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
928 * HOL: the predicate "inj" is now defined by translation to "inj_on";
930 * HOL/datatype: mutual_induct_tac no longer exists --
931 use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
933 * HOL/typedef: fixed type inference for representing set; type
934 arguments now have to occur explicitly on the rhs as type constraints;
936 * ZF: The con_defs part of an inductive definition may no longer refer
937 to constants declared in the same theory;
939 * HOL, ZF: the function mk_cases, generated by the inductive
940 definition package, has lost an argument. To simplify its result, it
941 uses the default simpset instead of a supplied list of theorems.
943 * HOL/List: the constructors of type list are now Nil and Cons;
945 * Simplifier: the type of the infix ML functions
946 setSSolver addSSolver setSolver addSolver
947 is now simpset * solver -> simpset where `solver' is a new abstract type
948 for packaging solvers. A solver is created via
949 mk_solver: string -> (thm list -> int -> tactic) -> solver
950 where the string argument is only a comment.
955 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
956 decision procedure for linear arithmetic. Currently it is used for
957 types `nat', `int', and `real' in HOL (see below); it can, should and
958 will be instantiated for other types and logics as well.
960 * The simplifier now accepts rewrite rules with flexible heads, eg
961 hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
962 They are applied like any rule with a non-pattern lhs, i.e. by first-order
968 * New Isabelle/Isar subsystem provides an alternative to traditional
969 tactical theorem proving; together with the ProofGeneral/isar user
970 interface it offers an interactive environment for developing human
971 readable proof documents (Isar == Intelligible semi-automated
972 reasoning); for further information see isatool doc isar-ref,
973 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
975 * improved and simplified presentation of theories: better HTML markup
976 (including colors), graph views in several sizes; isatool usedir now
977 provides a proper interface for user theories (via -P option); actual
978 document preparation based on (PDF)LaTeX is available as well (for
979 new-style theories only); see isatool doc system for more information;
981 * native support for Proof General, both for classic Isabelle and
984 * ML function thm_deps visualizes dependencies of theorems and lemmas,
985 using the graph browser tool;
987 * Isabelle manuals now also available as PDF;
989 * theory loader rewritten from scratch (may not be fully
990 bug-compatible); old loadpath variable has been replaced by show_path,
991 add_path, del_path, reset_path functions; new operations such as
992 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
995 * improved isatool install: option -k creates KDE application icon,
996 option -p DIR installs standalone binaries;
998 * added ML_PLATFORM setting (useful for cross-platform installations);
999 more robust handling of platform specific ML images for SML/NJ;
1001 * the settings environment is now statically scoped, i.e. it is never
1002 created again in sub-processes invoked from isabelle, isatool, or
1005 * path element specification '~~' refers to '$ISABELLE_HOME';
1007 * in locales, the "assumes" and "defines" parts may be omitted if
1010 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
1013 * new print_mode "HTML";
1015 * new flag show_tags controls display of tags of theorems (which are
1016 basically just comments that may be attached by some tools);
1018 * Isamode 2.6 requires patch to accomodate change of Isabelle font
1019 mode and goal output format:
1021 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
1023 < (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
1025 > (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
1026 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
1028 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
1030 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
1032 * function bind_thms stores lists of theorems (cf. bind_thm);
1034 * new shorthand tactics ftac, eatac, datac, fatac;
1036 * qed (and friends) now accept "" as result name; in that case the
1037 theorem is not stored, but proper checks and presentation of the
1040 * theorem database now also indexes constants "Trueprop", "all",
1041 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
1046 ** HOL arithmetic **
1048 * There are now decision procedures for linear arithmetic over nat and
1051 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
1052 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
1053 are treated as atomic; subformulae not involving type `nat' or `int'
1054 are ignored; quantified subformulae are ignored unless they are
1055 positive universal or negative existential. The tactic has to be
1056 invoked by hand and can be a little bit slow. In particular, the
1057 running time is exponential in the number of occurrences of `min' and
1058 `max', and `-' on `nat'.
1060 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
1061 (negated) (in)equalities among the premises and the conclusion into
1062 account (i.e. no compound formulae) and does not know about `min' and
1063 `max', and `-' on `nat'. It is fast and is used automatically by the
1066 NB: At the moment, these decision procedures do not cope with mixed
1067 nat/int formulae where the two parts interact, such as `m < n ==>
1070 * HOL/Numeral provides a generic theory of numerals (encoded
1071 efficiently as bit strings); setup for types nat/int/real is in place;
1072 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
1073 int, existing theories and proof scripts may require a few additional
1076 * integer division and remainder can now be performed on constant
1079 * many properties of integer multiplication, division and remainder
1082 * An interface to the Stanford Validity Checker (SVC) is available through the
1083 tactic svc_tac. Propositional tautologies and theorems of linear arithmetic
1084 are proved automatically. SVC must be installed separately, and its results
1085 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
1086 invocation of the underlying oracle). For SVC see
1087 http://verify.stanford.edu/SVC
1089 * IsaMakefile: the HOL-Real target now builds an actual image;
1094 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
1095 (in Isabelle/Isar) -- by Gertrud Bauer;
1097 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
1098 analysis for assembly languages with subtypes;
1100 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
1101 -- avoids syntactic ambiguities and treats state, transition, and
1102 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
1103 changed syntax and (many) tactics;
1105 * HOL/inductive: Now also handles more general introduction rules such
1106 as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
1107 theorems are now maintained within the theory (maintained via the
1110 * HOL/datatype: Now also handles arbitrarily branching datatypes
1111 (using function types) such as
1113 datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
1115 * HOL/record: record_simproc (part of the default simpset) takes care
1116 of selectors applied to updated records; record_split_tac is no longer
1117 part of the default claset; update_defs may now be removed from the
1118 simpset in many cases; COMPATIBILITY: old behavior achieved by
1120 claset_ref () := claset() addSWrapper record_split_wrapper;
1121 Delsimprocs [record_simproc]
1123 * HOL/typedef: fixed type inference for representing set; type
1124 arguments now have to occur explicitly on the rhs as type constraints;
1126 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
1127 names rather than an ML expression;
1129 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
1130 supplied later. Program schemes can be defined, such as
1131 "While B C s = (if B s then While B C (C s) else s)"
1132 where the well-founded relation can be chosen after B and C have been given.
1134 * HOL/List: the constructors of type list are now Nil and Cons;
1135 INCOMPATIBILITY: while [] and infix # syntax is still there, of
1136 course, ML tools referring to List.list.op # etc. have to be adapted;
1138 * HOL_quantifiers flag superseded by "HOL" print mode, which is
1139 disabled by default; run isabelle with option -m HOL to get back to
1140 the original Gordon/HOL-style output;
1142 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
1143 ALL x<=y. P, EX x<y. P, EX x<=y. P;
1145 * HOL basic syntax simplified (more orthogonal): all variants of
1146 All/Ex now support plain / symbolic / HOL notation; plain syntax for
1147 Eps operator is provided as well: "SOME x. P[x]";
1149 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
1151 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
1152 thus available for user theories;
1154 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
1155 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
1158 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
1159 several times and then mp;
1164 * the notation <<...>> is now available as a notation for sequences of
1167 * the simplifier is now installed
1169 * the axiom system has been generalized (thanks to Soren Heilmann)
1171 * the classical reasoner now has a default rule database
1176 * new primrec section allows primitive recursive functions to be given
1177 directly (as in HOL) over datatypes and the natural numbers;
1179 * new tactics induct_tac and exhaust_tac for induction (or case
1180 analysis) over datatypes and the natural numbers;
1182 * the datatype declaration of type T now defines the recursor T_rec;
1184 * simplification automatically does freeness reasoning for datatype
1187 * automatic type-inference, with AddTCs command to insert new
1188 type-checking rules;
1190 * datatype introduction rules are now added as Safe Introduction rules
1193 * the syntax "if P then x else y" is now available in addition to
1197 *** Internal programming interfaces ***
1199 * tuned simplifier trace output; new flag debug_simp;
1201 * structures Vartab / Termtab (instances of TableFun) offer efficient
1202 tables indexed by indexname_ord / term_ord (compatible with aconv);
1204 * AxClass.axclass_tac lost the theory argument;
1206 * tuned current_goals_markers semantics: begin / end goal avoids
1207 printing empty lines;
1209 * removed prs and prs_fn hook, which was broken because it did not
1210 include \n in its semantics, forcing writeln to add one
1211 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
1212 string -> unit if you really want to output text without newline;
1214 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
1215 plain output, interface builders may have to enable 'isabelle_font'
1216 mode to get Isabelle font glyphs as before;
1218 * refined token_translation interface; INCOMPATIBILITY: output length
1219 now of type real instead of int;
1221 * theory loader actions may be traced via new ThyInfo.add_hook
1222 interface (see src/Pure/Thy/thy_info.ML); example application: keep
1223 your own database of information attached to *whole* theories -- as
1224 opposed to intra-theory data slots offered via TheoryDataFun;
1226 * proper handling of dangling sort hypotheses (at last!);
1227 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
1228 extra sort hypotheses that can be witnessed from the type signature;
1229 the force_strip_shyps flag is gone, any remaining shyps are simply
1230 left in the theorem (with a warning issued by strip_shyps_warning);
1234 New in Isabelle98-1 (October 1998)
1235 ----------------------------------
1237 *** Overview of INCOMPATIBILITIES (see below for more details) ***
1239 * several changes of automated proof tools;
1241 * HOL: major changes to the inductive and datatype packages, including
1242 some minor incompatibilities of theory syntax;
1244 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
1247 * HOL: removed duplicate thms in Arith:
1248 less_imp_add_less should be replaced by trans_less_add1
1249 le_imp_add_le should be replaced by trans_le_add1
1251 * HOL: unary minus is now overloaded (new type constraints may be
1254 * HOL and ZF: unary minus for integers is now #- instead of #~. In
1255 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
1256 now taken as an integer constant.
1258 * Pure: ML function 'theory_of' renamed to 'theory';
1264 1. Asm_full_simp_tac is now more aggressive.
1265 1. It will sometimes reorient premises if that increases their power to
1267 2. It does no longer proceed strictly from left to right but may also
1268 rotate premises to achieve further simplification.
1269 For compatibility reasons there is now Asm_lr_simp_tac which is like the
1270 old Asm_full_simp_tac in that it does not rotate premises.
1271 2. The simplifier now knows a little bit about nat-arithmetic.
1273 * Classical reasoner: wrapper mechanism for the classical reasoner now
1274 allows for selected deletion of wrappers, by introduction of names for
1275 wrapper functionals. This implies that addbefore, addSbefore,
1276 addaltern, and addSaltern now take a pair (name, tactic) as argument,
1277 and that adding two tactics with the same name overwrites the first
1278 one (emitting a warning).
1279 type wrapper = (int -> tactic) -> (int -> tactic)
1280 setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
1281 addWrapper, addSWrapper: claset * (string * wrapper) -> claset
1282 delWrapper, delSWrapper: claset * string -> claset
1283 getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
1285 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
1286 semantics; addbefore now affects only the unsafe part of step_tac
1287 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
1288 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
1291 * Classical reasoner: setwrapper to setWrapper and compwrapper to
1292 compWrapper; added safe wrapper (and access functions for it);
1294 * HOL/split_all_tac is now much faster and fails if there is nothing
1295 to split. Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
1296 and the names of the automatically generated variables have changed.
1297 split_all_tac has moved within claset() from unsafe wrappers to safe
1298 wrappers, which means that !!-bound variables are split much more
1299 aggressively, and safe_tac and clarify_tac now split such variables.
1300 If this splitting is not appropriate, use delSWrapper "split_all_tac".
1301 Note: the same holds for record_split_tac, which does the job of
1302 split_all_tac for record fields.
1304 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
1305 permanently to the default simpset using Addsplits just like
1306 Addsimps. They can be removed via Delsplits just like
1307 Delsimps. Lower-case versions are also available.
1309 * HOL/Simplifier: The rule split_if is now part of the default
1310 simpset. This means that the simplifier will eliminate all occurrences
1311 of if-then-else in the conclusion of a goal. To prevent this, you can
1312 either remove split_if completely from the default simpset by
1313 `Delsplits [split_if]' or remove it in a specific call of the
1314 simplifier using `... delsplits [split_if]'. You can also add/delete
1315 other case splitting rules to/from the default simpset: every datatype
1316 generates suitable rules `split_t_case' and `split_t_case_asm' (where
1317 t is the name of the datatype).
1319 * Classical reasoner / Simplifier combination: new force_tac (and
1320 derivatives Force_tac, force) combines rewriting and classical
1321 reasoning (and whatever other tools) similarly to auto_tac, but is
1322 aimed to solve the given subgoal completely.
1327 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
1328 and `goalw': the theory is no longer needed as an explicit argument -
1329 the current theory context is used; assumptions are no longer returned
1330 at the ML-level unless one of them starts with ==> or !!; it is
1331 recommended to convert to these new commands using isatool fixgoal
1332 (backup your sources first!);
1334 * new top-level commands 'thm' and 'thms' for retrieving theorems from
1335 the current theory context, and 'theory' to lookup stored theories;
1337 * new theory section 'locale' for declaring constants, assumptions and
1338 definitions that have local scope;
1340 * new theory section 'nonterminals' for purely syntactic types;
1342 * new theory section 'setup' for generic ML setup functions
1343 (e.g. package initialization);
1345 * the distribution now includes Isabelle icons: see
1346 lib/logo/isabelle-{small,tiny}.xpm;
1348 * isatool install - install binaries with absolute references to
1351 * isatool logo -- create instances of the Isabelle logo (as EPS);
1353 * print mode 'emacs' reserved for Isamode;
1355 * support multiple print (ast) translations per constant name;
1357 * theorems involving oracles are now printed with a suffixed [!];
1362 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
1364 * HOL/inductive package reorganized and improved: now supports mutual
1370 oddI "n : EVEN ==> Suc n : ODD"
1371 evenI "n : ODD ==> Suc n : EVEN"
1373 new theorem list "elims" contains an elimination rule for each of the
1374 recursive sets; inductive definitions now handle disjunctive premises
1375 correctly (also ZF);
1377 INCOMPATIBILITIES: requires Inductive as an ancestor; component
1378 "mutual_induct" no longer exists - the induction rule is always
1379 contained in "induct";
1382 * HOL/datatype package re-implemented and greatly improved: now
1383 supports mutually recursive datatypes such as
1386 'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
1387 | SUM ('a aexp) ('a aexp)
1388 | DIFF ('a aexp) ('a aexp)
1391 'a bexp = LESS ('a aexp) ('a aexp)
1392 | AND ('a bexp) ('a bexp)
1393 | OR ('a bexp) ('a bexp)
1395 as well as indirectly recursive datatypes such as
1398 ('a, 'b) term = Var 'a
1399 | App 'b ((('a, 'b) term) list)
1401 The new tactic mutual_induct_tac [<var_1>, ..., <var_n>] i performs
1402 induction on mutually / indirectly recursive datatypes.
1404 Primrec equations are now stored in theory and can be accessed via
1405 <function_name>.simps.
1409 - Theories using datatypes must now have theory Datatype as an
1411 - The specific <typename>.induct_tac no longer exists - use the
1412 generic induct_tac instead.
1413 - natE has been renamed to nat.exhaust - use exhaust_tac
1414 instead of res_inst_tac ... natE. Note that the variable
1415 names in nat.exhaust differ from the names in natE, this
1416 may cause some "fragile" proofs to fail.
1417 - The theorems split_<typename>_case and split_<typename>_case_asm
1418 have been renamed to <typename>.split and <typename>.split_asm.
1419 - Since default sorts of type variables are now handled correctly,
1420 some datatype definitions may have to be annotated with explicit
1422 - Primrec definitions no longer require function name and type
1423 of recursive argument.
1425 Consider using isatool fixdatatype to adapt your theories and proof
1426 scripts to the new package (backup your sources first!).
1429 * HOL/record package: considerably improved implementation; now
1430 includes concrete syntax for record types, terms, updates; theorems
1431 for surjective pairing and splitting !!-bound record variables; proof
1432 support is as follows:
1434 1) standard conversions (selectors or updates applied to record
1435 constructor terms) are part of the standard simpset;
1437 2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
1438 made part of standard simpset and claset via addIffs;
1440 3) a tactic for record field splitting (record_split_tac) is part of
1441 the standard claset (addSWrapper);
1443 To get a better idea about these rules you may retrieve them via
1444 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
1445 the name of your record type.
1447 The split tactic 3) conceptually simplifies by the following rule:
1449 "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
1451 Thus any record variable that is bound by meta-all will automatically
1452 blow up into some record constructor term, consequently the
1453 simplifications of 1), 2) apply. Thus force_tac, auto_tac etc. shall
1454 solve record problems automatically.
1457 * reorganized the main HOL image: HOL/Integ and String loaded by
1458 default; theory Main includes everything;
1460 * automatic simplification of integer sums and comparisons, using cancellation;
1462 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
1464 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
1466 * many new identities for unions, intersections, set difference, etc.;
1468 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
1469 called split_if, split_split, split_sum_case and split_nat_case (to go
1470 with add/delsplits);
1472 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
1473 (?x::unit) = (); this is made part of the default simpset, which COULD
1474 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
1475 'Delsimprocs [unit_eq_proc];' as last resort); also note that
1476 unit_abs_eta_conv is added in order to counter the effect of
1477 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
1480 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
1483 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
1484 It and 'sym RS equals0D' are now in the default claset, giving automatic
1485 disjointness reasoning but breaking a few old proofs.
1487 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
1488 to 'converse' from 'inverse' (for compatibility with ZF and some
1491 * HOL/recdef can now declare non-recursive functions, with {} supplied as
1492 the well-founded relation;
1494 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
1495 Compl A. The "Compl" syntax remains available as input syntax for this
1498 * HOL/Update: new theory of function updates:
1499 f(a:=b) == %x. if x=a then b else f x
1500 may also be iterated as in f(a:=b,c:=d,...);
1502 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
1505 - new function list_update written xs[i:=v] that updates the i-th
1506 list position. May also be iterated as in xs[i:=a,j:=b,...].
1507 - new function `upt' written [i..j(] which generates the list
1508 [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
1509 bound write [i..j], which is a shorthand for [i..j+1(].
1510 - new lexicographic orderings and corresponding wellfoundedness theorems.
1513 - removed 'pred' (predecessor) function;
1514 - generalized some theorems about n-1;
1515 - many new laws about "div" and "mod";
1516 - new laws about greatest common divisors (see theory ex/Primes);
1518 * HOL/Relation: renamed the relational operator r^-1 "converse"
1519 instead of "inverse";
1521 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
1522 of the multiset ordering;
1524 * directory HOL/Real: a construction of the reals using Dedekind cuts
1525 (not included by default);
1527 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
1529 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
1530 programs, i.e. different program variables may have different types.
1532 * calling (stac rew i) now fails if "rew" has no effect on the goal
1533 [previously, this check worked only if the rewrite rule was unconditional]
1534 Now rew can involve either definitions or equalities (either == or =).
1539 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
1540 only the theorems proved on ZF.ML;
1542 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
1543 It and 'sym RS equals0D' are now in the default claset, giving automatic
1544 disjointness reasoning but breaking a few old proofs.
1546 * ZF/Update: new theory of function updates
1547 with default rewrite rule f(x:=y) ` z = if(z=x, y, f`z)
1548 may also be iterated as in f(a:=b,c:=d,...);
1550 * in let x=t in u(x), neither t nor u(x) has to be an FOL term.
1552 * calling (stac rew i) now fails if "rew" has no effect on the goal
1553 [previously, this check worked only if the rewrite rule was unconditional]
1554 Now rew can involve either definitions or equalities (either == or =).
1556 * case_tac provided for compatibility with HOL
1557 (like the old excluded_middle_tac, but with subgoals swapped)
1560 *** Internal programming interfaces ***
1562 * Pure: several new basic modules made available for general use, see
1563 also src/Pure/README;
1565 * improved the theory data mechanism to support encapsulation (data
1566 kind name replaced by private Object.kind, acting as authorization
1567 key); new type-safe user interface via functor TheoryDataFun; generic
1568 print_data function becomes basically useless;
1570 * removed global_names compatibility flag -- all theory declarations
1571 are qualified by default;
1573 * module Pure/Syntax now offers quote / antiquote translation
1574 functions (useful for Hoare logic etc. with implicit dependencies);
1575 see HOL/ex/Antiquote for an example use;
1577 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
1580 * new tactical CHANGED_GOAL for checking that a tactic modifies a
1583 * Display.print_goals function moved to Locale.print_goals;
1585 * standard print function for goals supports current_goals_markers
1586 variable for marking begin of proof, end of proof, start of goal; the
1587 default is ("", "", ""); setting current_goals_markers := ("<proof>",
1588 "</proof>", "<goal>") causes SGML like tagged proof state printing,
1593 New in Isabelle98 (January 1998)
1594 --------------------------------
1596 *** Overview of INCOMPATIBILITIES (see below for more details) ***
1598 * changed lexical syntax of terms / types: dots made part of long
1599 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
1601 * simpset (and claset) reference variable replaced by functions
1602 simpset / simpset_ref;
1604 * no longer supports theory aliases (via merge) and non-trivial
1605 implicit merge of thms' signatures;
1607 * most internal names of constants changed due to qualified names;
1609 * changed Pure/Sequence interface (see Pure/seq.ML);
1612 *** General Changes ***
1614 * hierachically structured name spaces (for consts, types, axms, thms
1615 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
1616 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
1617 isatool fixdots ensures space after dots (e.g. "%x. x"); set
1618 long_names for fully qualified output names; NOTE: ML programs
1619 (special tactics, packages etc.) referring to internal names may have
1620 to be adapted to cope with fully qualified names; in case of severe
1621 backward campatibility problems try setting 'global_names' at compile
1622 time to have enrything declared within a flat name space; one may also
1623 fine tune name declarations in theories via the 'global' and 'local'
1626 * reimplemented the implicit simpset and claset using the new anytype
1627 data filed in signatures; references simpset:simpset ref etc. are
1628 replaced by functions simpset:unit->simpset and
1629 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
1630 to patch your ML files accordingly;
1632 * HTML output now includes theory graph data for display with Java
1633 applet or isatool browser; data generated automatically via isatool
1634 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
1636 * defs may now be conditional; improved rewrite_goals_tac to handle
1637 conditional equations;
1639 * defs now admits additional type arguments, using TYPE('a) syntax;
1641 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
1642 creates a new theory node; implicit merge of thms' signatures is
1643 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
1644 transfer:theory->thm->thm in (rare) cases;
1646 * improved handling of draft signatures / theories; draft thms (and
1647 ctyps, cterms) are automatically promoted to real ones;
1649 * slightly changed interfaces for oracles: admit many per theory, named
1650 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
1652 * print_goals: optional output of const types (set show_consts and
1655 * improved output of warnings (###) and errors (***);
1657 * subgoal_tac displays a warning if the new subgoal has type variables;
1659 * removed old README and Makefiles;
1661 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
1663 * removed obsolete init_pps and init_database;
1665 * deleted the obsolete tactical STATE, which was declared by
1666 fun STATE tacfun st = tacfun st st;
1668 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
1669 (which abbreviates $HOME);
1671 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
1672 use isatool fixseq to adapt your ML programs (this works for fully
1673 qualified references to the Sequence structure only!);
1675 * use_thy no longer requires writable current directory; it always
1676 reloads .ML *and* .thy file, if either one is out of date;
1679 *** Classical Reasoner ***
1681 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
1682 tactics that use classical reasoning to simplify a subgoal without
1683 splitting it into several subgoals;
1685 * Safe_tac: like safe_tac but uses the default claset;
1690 * added simplification meta rules:
1691 (asm_)(full_)simplify: simpset -> thm -> thm;
1693 * simplifier.ML no longer part of Pure -- has to be loaded by object
1696 * added prems argument to simplification procedures;
1698 * HOL, FOL, ZF: added infix function `addsplits':
1699 instead of `<simpset> setloop (split_tac <thms>)'
1700 you can simply write `<simpset> addsplits <thms>'
1705 * TYPE('a) syntax for type reflection terms;
1707 * no longer handles consts with name "" -- declare as 'syntax' instead;
1709 * pretty printer: changed order of mixfix annotation preference (again!);
1711 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
1716 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
1717 with `addloop' of the simplifier to faciliate case splitting in premises.
1719 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
1721 * HOL/Auth: new protocol proofs including some for the Internet
1724 * HOL/Map: new theory of `maps' a la VDM;
1726 * HOL/simplifier: simplification procedures nat_cancel_sums for
1727 cancelling out common nat summands from =, <, <= (in)equalities, or
1728 differences; simplification procedures nat_cancel_factor for
1729 cancelling common factor from =, <, <= (in)equalities over natural
1730 sums; nat_cancel contains both kinds of procedures, it is installed by
1731 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
1733 * HOL/simplifier: terms of the form
1734 `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)' (or t=x)
1736 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
1737 and those of the form
1738 `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)' (or t=x)
1740 `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
1743 Each datatype `t' now comes with a theorem `split_t_case' of the form
1745 P(t_case f1 ... fn x) =
1746 ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
1748 (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
1751 and a theorem `split_t_case_asm' of the form
1753 P(t_case f1 ... fn x) =
1754 ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
1756 (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
1758 which can be added to a simpset via `addsplits'. The existing theorems
1759 expand_list_case and expand_option_case have been renamed to
1760 split_list_case and split_option_case.
1763 - `pred n' is automatically converted to `n-1'.
1764 Users are strongly encouraged not to use `pred' any longer,
1765 because it will disappear altogether at some point.
1766 - Users are strongly encouraged to write "0 < n" rather than
1767 "n ~= 0". Theorems and proof tools have been modified towards this
1771 the function "set_of_list" has been renamed "set" (and its theorems too);
1772 the function "nth" now takes its arguments in the reverse order and
1773 has acquired the infix notation "!" as in "xs!n".
1775 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
1777 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
1778 specialist theorems (like UN1_I) are gone. Similarly for (INT x.B x);
1780 * HOL/record: extensible records with schematic structural subtyping
1781 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
1782 still lacks various theorems and concrete record syntax;
1787 * removed "axioms" and "generated by" sections;
1789 * replaced "ops" section by extended "consts" section, which is capable of
1790 handling the continuous function space "->" directly;
1793 . proves theorems immediately and stores them in the theory,
1794 . creates hierachical name space,
1795 . now uses normal mixfix annotations (instead of cinfix...),
1796 . minor changes to some names and values (for consistency),
1797 . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
1798 . separator between mutual domain defs: changed "," to "and",
1799 . improved handling of sort constraints; now they have to
1800 appear on the left-hand side of the equations only;
1802 * fixed LAM <x,y,zs>.b syntax;
1804 * added extended adm_tac to simplifier in HOLCF -- can now discharge
1805 adm (%x. P (t x)), where P is chainfinite and t continuous;
1810 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
1811 with `addloop' of the simplifier to faciliate case splitting in premises.
1813 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
1814 in HOL, they strip ALL and --> from proved theorems;
1818 New in Isabelle94-8 (May 1997)
1819 ------------------------------
1821 *** General Changes ***
1823 * new utilities to build / run / maintain Isabelle etc. (in parts
1824 still somewhat experimental); old Makefiles etc. still functional;
1826 * new 'Isabelle System Manual';
1828 * INSTALL text, together with ./configure and ./build scripts;
1830 * reimplemented type inference for greater efficiency, better error
1831 messages and clean internal interface;
1833 * prlim command for dealing with lots of subgoals (an easier way of
1834 setting goals_limit);
1839 * supports alternative (named) syntax tables (parser and pretty
1840 printer); internal interface is provided by add_modesyntax(_i);
1842 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
1843 be used in conjunction with the Isabelle symbol font; uses the
1844 "symbols" syntax table;
1846 * added token_translation interface (may translate name tokens in
1847 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
1848 the current print_mode); IMPORTANT: user print translation functions
1849 are responsible for marking newly introduced bounds
1850 (Syntax.mark_boundT);
1852 * token translations for modes "xterm" and "xterm_color" that display
1853 names in bold, underline etc. or colors (which requires a color
1856 * infixes may now be declared with names independent of their syntax;
1858 * added typed_print_translation (like print_translation, but may
1859 access type of constant);
1862 *** Classical Reasoner ***
1864 Blast_tac: a new tactic! It is often more powerful than fast_tac, but has
1865 some limitations. Blast_tac...
1866 + ignores addss, addbefore, addafter; this restriction is intrinsic
1867 + ignores elimination rules that don't have the correct format
1868 (the conclusion MUST be a formula variable)
1869 + ignores types, which can make HOL proofs fail
1870 + rules must not require higher-order unification, e.g. apply_type in ZF
1871 [message "Function Var's argument not a bound variable" relates to this]
1872 + its proof strategy is more general but can actually be slower
1874 * substitution with equality assumptions no longer permutes other
1877 * minor changes in semantics of addafter (now called addaltern); renamed
1878 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
1879 (and access functions for it);
1881 * improved combination of classical reasoner and simplifier:
1882 + functions for handling clasimpsets
1883 + improvement of addss: now the simplifier is called _after_ the
1885 + safe variant of addss called addSss: uses safe simplifications
1886 _during_ the safe steps. It is more complete as it allows multiple
1887 instantiations of unknowns (e.g. with slow_tac).
1891 * added interface for simplification procedures (functions that
1892 produce *proven* rewrite rules on the fly, depending on current
1895 * ordering on terms as parameter (used for ordered rewriting);
1897 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
1899 * the solver is now split into a safe and an unsafe part.
1900 This should be invisible for the normal user, except that the
1901 functions setsolver and addsolver have been renamed to setSolver and
1902 addSolver; added safe_asm_full_simp_tac;
1907 * a generic induction tactic `induct_tac' which works for all datatypes and
1908 also for type `nat';
1910 * a generic case distinction tactic `exhaust_tac' which works for all
1911 datatypes and also for type `nat';
1913 * each datatype comes with a function `size';
1915 * patterns in case expressions allow tuple patterns as arguments to
1916 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
1918 * primrec now also works with type nat;
1920 * recdef: a new declaration form, allows general recursive functions to be
1921 defined in theory files. See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
1923 * the constant for negation has been renamed from "not" to "Not" to
1924 harmonize with FOL, ZF, LK, etc.;
1926 * HOL/ex/LFilter theory of a corecursive "filter" functional for
1929 * HOL/Modelcheck demonstrates invocation of model checker oracle;
1931 * HOL/ex/Ring.thy declares cring_simp, which solves equational
1932 problems in commutative rings, using axiomatic type classes for + and *;
1934 * more examples in HOL/MiniML and HOL/Auth;
1936 * more default rewrite rules for quantifiers, union/intersection;
1938 * a new constant `arbitrary == @x.False';
1940 * HOLCF/IOA replaces old HOL/IOA;
1942 * HOLCF changes: derived all rules and arities
1943 + axiomatic type classes instead of classes
1944 + typedef instead of faking type definitions
1945 + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
1946 + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
1947 + eliminated the types void, one, tr
1948 + use unit lift and bool lift (with translations) instead of one and tr
1949 + eliminated blift from Lift3.thy (use Def instead of blift)
1950 all eliminated rules are derived as theorems --> no visible changes ;
1955 * ZF now has Fast_tac, Simp_tac and Auto_tac. Union_iff is a now a default
1956 rewrite rule; this may affect some proofs. eq_cs is gone but can be put back
1957 as ZF_cs addSIs [equalityI];
1961 New in Isabelle94-7 (November 96)
1962 ---------------------------------
1964 * allowing negative levels (as offsets) in prlev and choplev;
1966 * super-linear speedup for large simplifications;
1968 * FOL, ZF and HOL now use miniscoping: rewriting pushes
1969 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
1970 FAIL); can suppress it using the command Delsimps (ex_simps @
1971 all_simps); De Morgan laws are also now included, by default;
1973 * improved printing of ==> : ~:
1975 * new object-logic "Sequents" adds linear logic, while replacing LK
1976 and Modal (thanks to Sara Kalvala);
1978 * HOL/Auth: correctness proofs for authentication protocols;
1980 * HOL: new auto_tac combines rewriting and classical reasoning (many
1981 examples on HOL/Auth);
1983 * HOL: new command AddIffs for declaring theorems of the form P=Q to
1984 the rewriter and classical reasoner simultaneously;
1986 * function uresult no longer returns theorems in "standard" format;
1987 regain previous version by: val uresult = standard o uresult;
1994 * oracles -- these establish an interface between Isabelle and trusted
1995 external reasoners, which may deliver results as theorems;
1997 * proof objects (in particular record all uses of oracles);
1999 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
2001 * "constdefs" section in theory files;
2003 * "primrec" section (HOL) no longer requires names;
2005 * internal type "tactic" now simply "thm -> thm Sequence.seq";
2012 * reduced space requirements;
2014 * automatic HTML generation from theories;
2016 * theory files no longer require "..." (quotes) around most types;
2018 * new examples, including two proofs of the Church-Rosser theorem;
2020 * non-curried (1994) version of HOL is no longer distributed;
2027 * greatly reduced space requirements;
2029 * theory files (.thy) no longer require \...\ escapes at line breaks;
2031 * searchable theorem database (see the section "Retrieving theorems" on
2032 page 8 of the Reference Manual);
2034 * new examples, including Grabczewski's monumental case study of the
2037 * The previous version of HOL renamed to Old_HOL;
2039 * The new version of HOL (previously called CHOL) uses a curried syntax
2040 for functions. Application looks like f a b instead of f(a,b);
2042 * Mutually recursive inductive definitions finally work in HOL;
2044 * In ZF, pattern-matching on tuples is now available in all abstractions and
2045 translates to the operator "split";
2052 * new infix operator, addss, allowing the classical reasoner to
2053 perform simplification at each step of its search. Example:
2054 fast_tac (cs addss ss)
2056 * a new logic, CHOL, the same as HOL, but with a curried syntax
2057 for functions. Application looks like f a b instead of f(a,b). Also pairs
2058 look like (a,b) instead of <a,b>;
2060 * PLEASE NOTE: CHOL will eventually replace HOL!
2062 * In CHOL, pattern-matching on tuples is now available in all abstractions.
2063 It translates to the operator "split". A new theory of integers is available;
2065 * In ZF, integer numerals now denote two's-complement binary integers.
2066 Arithmetic operations can be performed by rewriting. See ZF/ex/Bin.ML;
2068 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
2069 of the Axiom of Choice;
2076 * Significantly faster resolution;
2078 * the different sections in a .thy file can now be mixed and repeated
2081 * Database of theorems for FOL, HOL and ZF. New
2082 commands including qed, qed_goal and bind_thm store theorems in the database.
2084 * Simple database queries: return a named theorem (get_thm) or all theorems of
2085 a given theory (thms_of), or find out what theory a theorem was proved in
2088 * Bugs fixed in the inductive definition and datatype packages;
2090 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
2091 and HOL_dup_cs obsolete;
2093 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
2096 * Simpler definition of function space in ZF;
2098 * new results about cardinal and ordinal arithmetic in ZF;
2100 * 'subtype' facility in HOL for introducing new types as subsets of existing