NEWS
author wenzelm
Tue Aug 06 11:24:27 2002 +0200 (2002-08-06)
changeset 13463 07747943c626
parent 13459 83f41b047a39
child 13478 9cfbcb9acfef
permissions -rw-r--r--
* Provers: Simplifier.simproc(_i) now provide sane interface for
setting up simprocs;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in this Isabelle release
     6 ----------------------------
     7 
     8 *** General ***
     9 
    10 * Pure: locale specifications now produce predicate definitions
    11 according to the body of text (covering assumptions modulo local
    12 definitions); predicate "loc_axioms" covers newly introduced text,
    13 while "loc" is cumulative wrt. all included locale expressions; the
    14 latter view is presented only on export into the global theory
    15 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    16 on the old view without predicates;
    17 
    18 * Pure: predefined locales "var" and "struct" are useful for sharing
    19 parameters (as in CASL, for example); just specify something like
    20 ``var x + var y + struct M'' as import;
    21 
    22 * Pure: improved thms_containing: proper indexing of facts instead of
    23 raw theorems; check validity of results wrt. current name space;
    24 include local facts of proof configuration (also covers active
    25 locales); an optional limit for the number of printed facts may be
    26 given (the default is 40);
    27 
    28 * Provers: improved induct method: assumptions introduced by case
    29 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    30 the goal statement); "foo" still refers to all facts collectively;
    31 
    32 * Provers: Simplifier.simproc(_i) now provide sane interface for
    33 setting up simprocs;
    34 
    35 
    36 *** HOL ***
    37 
    38 * 'typedef' command has new option "open" to suppress the set
    39 definition;
    40 
    41 * attribute [symmetric] now works for relations as well; it turns
    42 (x,y) : R^-1 into (y,x) : R, and vice versa;
    43 
    44 * arith(_tac) does now know about div k and mod k where k is a numeral
    45 of type nat or int. It can solve simple goals like
    46 
    47   "0 < n ==> n div 2 < (n::nat)"
    48 
    49 but fails if divisibility plays a role like in
    50 
    51   "n div 2 + (n+1) div 2 = (n::nat)"
    52 
    53 * simp's arithmetic capabilities have been enhanced a bit: it now
    54 takes ~= in premises into account (by performing a case split);
    55 
    56 
    57 
    58 New in Isabelle2002 (March 2002)
    59 --------------------------------
    60 
    61 *** Document preparation ***
    62 
    63 * greatly simplified document preparation setup, including more
    64 graceful interpretation of isatool usedir -i/-d/-D options, and more
    65 instructive isatool mkdir; users should basically be able to get
    66 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    67 users may run a separate document processing stage manually like this:
    68 "isatool usedir -D output HOL Test && isatool document Test/output";
    69 
    70 * theory dependency graph may now be incorporated into documents;
    71 isatool usedir -g true will produce session_graph.eps/.pdf for use
    72 with \includegraphics of LaTeX;
    73 
    74 * proper spacing of consecutive markup elements, especially text
    75 blocks after section headings;
    76 
    77 * support bold style (for single symbols only), input syntax is like
    78 this: "\<^bold>\<alpha>" or "\<^bold>A";
    79 
    80 * \<bullet> is now output as bold \cdot by default, which looks much
    81 better in printed text;
    82 
    83 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    84 note that these symbols are currently unavailable in Proof General /
    85 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
    86 
    87 * isatool latex no longer depends on changed TEXINPUTS, instead
    88 isatool document copies the Isabelle style files to the target
    89 location;
    90 
    91 
    92 *** Isar ***
    93 
    94 * Pure/Provers: improved proof by cases and induction;
    95   - 'case' command admits impromptu naming of parameters (such as
    96     "case (Suc n)");
    97   - 'induct' method divinates rule instantiation from the inductive
    98     claim; no longer requires excessive ?P bindings for proper
    99     instantiation of cases;
   100   - 'induct' method properly enumerates all possibilities of set/type
   101     rules; as a consequence facts may be also passed through *type*
   102     rules without further ado;
   103   - 'induct' method now derives symbolic cases from the *rulified*
   104     rule (before it used to rulify cases stemming from the internal
   105     atomized version); this means that the context of a non-atomic
   106     statement becomes is included in the hypothesis, avoiding the
   107     slightly cumbersome show "PROP ?case" form;
   108   - 'induct' may now use elim-style induction rules without chaining
   109     facts, using ``missing'' premises from the goal state; this allows
   110     rules stemming from inductive sets to be applied in unstructured
   111     scripts, while still benefitting from proper handling of non-atomic
   112     statements; NB: major inductive premises need to be put first, all
   113     the rest of the goal is passed through the induction;
   114   - 'induct' proper support for mutual induction involving non-atomic
   115     rule statements (uses the new concept of simultaneous goals, see
   116     below);
   117   - append all possible rule selections, but only use the first
   118     success (no backtracking);
   119   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   120   - undeclared rule case names default to numbers 1, 2, 3, ...;
   121   - added 'print_induct_rules' (covered by help item in recent Proof
   122     General versions);
   123   - moved induct/cases attributes to Pure, methods to Provers;
   124   - generic method setup instantiated for FOL and HOL;
   125 
   126 * Pure: support multiple simultaneous goal statements, for example
   127 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   128 meta-level mechanism, this acts as if several individual goals had
   129 been stated separately; in particular common proof methods need to be
   130 repeated in order to cover all claims; note that a single elimination
   131 step is *not* sufficient to establish the two conjunctions, so this
   132 fails:
   133 
   134   assume "A & B" then have A and B ..   (*".." fails*)
   135 
   136 better use "obtain" in situations as above; alternative refer to
   137 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   138 
   139 * Pure: proper integration with ``locales''; unlike the original
   140 version by Florian Kammüller, Isar locales package high-level proof
   141 contexts rather than raw logical ones (e.g. we admit to include
   142 attributes everywhere); operations on locales include merge and
   143 rename; support for implicit arguments (``structures''); simultaneous
   144 type-inference over imports and text; see also HOL/ex/Locales.thy for
   145 some examples;
   146 
   147 * Pure: the following commands have been ``localized'', supporting a
   148 target locale specification "(in name)": 'lemma', 'theorem',
   149 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   150 stored both within the locale and at the theory level (exported and
   151 qualified by the locale name);
   152 
   153 * Pure: theory goals may now be specified in ``long'' form, with
   154 ad-hoc contexts consisting of arbitrary locale elements. for example
   155 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   156 definitions may be given, too); the result is a meta-level rule with
   157 the context elements being discharged in the obvious way;
   158 
   159 * Pure: new proof command 'using' allows to augment currently used
   160 facts after a goal statement ('using' is syntactically analogous to
   161 'apply', but acts on the goal's facts only); this allows chained facts
   162 to be separated into parts given before and after a claim, as in
   163 ``from a and b have C using d and e <proof>'';
   164 
   165 * Pure: renamed "antecedent" case to "rule_context";
   166 
   167 * Pure: new 'judgment' command records explicit information about the
   168 object-logic embedding (used by several tools internally); no longer
   169 use hard-wired "Trueprop";
   170 
   171 * Pure: added 'corollary' command;
   172 
   173 * Pure: fixed 'token_translation' command;
   174 
   175 * Pure: removed obsolete 'exported' attribute;
   176 
   177 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   178 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   179 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   180 
   181 * Pure: method 'atomize' presents local goal premises as object-level
   182 statements (atomic meta-level propositions); setup controlled via
   183 rewrite rules declarations of 'atomize' attribute; example
   184 application: 'induct' method with proper rule statements in improper
   185 proof *scripts*;
   186 
   187 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   188 now consider the syntactic context of assumptions, giving a better
   189 chance to get type-inference of the arguments right (this is
   190 especially important for locales);
   191 
   192 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   193 mode;
   194 
   195 * Pure/obtain: the formal conclusion "thesis", being marked as
   196 ``internal'', may no longer be reference directly in the text;
   197 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   198 situations;
   199 
   200 * Pure: generic 'sym' attribute which declares a rule both as pure
   201 'elim?' and for the 'symmetric' operation;
   202 
   203 * Pure: marginal comments ``--'' may now occur just anywhere in the
   204 text; the fixed correlation with particular command syntax has been
   205 discontinued;
   206 
   207 * Pure: new method 'rules' is particularly well-suited for proof
   208 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   209 but often produces more compact proof terms with less detours;
   210 
   211 * Pure/Provers/classical: simplified integration with pure rule
   212 attributes and methods; the classical "intro?/elim?/dest?"
   213 declarations coincide with the pure ones; the "rule" method no longer
   214 includes classically swapped intros; "intro" and "elim" methods no
   215 longer pick rules from the context; also got rid of ML declarations
   216 AddXIs/AddXEs/AddXDs; all of this has some potential for
   217 INCOMPATIBILITY;
   218 
   219 * Provers/classical: attribute 'swapped' produces classical inversions
   220 of introduction rules;
   221 
   222 * Provers/simplifier: 'simplified' attribute may refer to explicit
   223 rules instead of full simplifier context; 'iff' attribute handles
   224 conditional rules;
   225 
   226 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   227 
   228 * HOL: 'recdef' now fails on unfinished automated proofs, use
   229 "(permissive)" option to recover old behavior;
   230 
   231 * HOL: 'inductive' no longer features separate (collective) attributes
   232 for 'intros' (was found too confusing);
   233 
   234 * HOL: properly declared induction rules less_induct and
   235 wf_induct_rule;
   236 
   237 
   238 *** HOL ***
   239 
   240 * HOL: moved over to sane numeral syntax; the new policy is as
   241 follows:
   242 
   243   - 0 and 1 are polymorphic constants, which are defined on any
   244   numeric type (nat, int, real etc.);
   245 
   246   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   247   binary representation internally;
   248 
   249   - type nat has special constructor Suc, and generally prefers Suc 0
   250   over 1::nat and Suc (Suc 0) over 2::nat;
   251 
   252 This change may cause significant problems of INCOMPATIBILITY; here
   253 are some hints on converting existing sources:
   254 
   255   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   256   entities, so expressions involving "-" (unary or binary minus) need
   257   to be spaced properly;
   258 
   259   - existing occurrences of "1" may need to be constraint "1::nat" or
   260   even replaced by Suc 0; similar for old "2";
   261 
   262   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   263 
   264   - remove all special provisions on numerals in proofs;
   265 
   266 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   267 representation (depends on bin_arith_simps in the default context);
   268 
   269 * HOL: symbolic syntax for x^2 (numeral 2);
   270 
   271 * HOL: the class of all HOL types is now called "type" rather than
   272 "term"; INCOMPATIBILITY, need to adapt references to this type class
   273 in axclass/classes, instance/arities, and (usually rare) occurrences
   274 in typings (of consts etc.); internally the class is called
   275 "HOL.type", ML programs should refer to HOLogic.typeS;
   276 
   277 * HOL/record package improvements:
   278   - new derived operations "fields" to build a partial record section,
   279     "extend" to promote a fixed record to a record scheme, and
   280     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   281     declared as simp by default;
   282   - shared operations ("more", "fields", etc.) now need to be always
   283     qualified) --- potential INCOMPATIBILITY;
   284   - removed "make_scheme" operations (use "make" with "extend") --
   285     INCOMPATIBILITY;
   286   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   287   - provides cases/induct rules for use with corresponding Isar
   288     methods (for concrete records, record schemes, concrete more
   289     parts, and schematic more parts -- in that order);
   290   - internal definitions directly based on a light-weight abstract
   291     theory of product types over typedef rather than datatype;
   292 
   293 * HOL: generic code generator for generating executable ML code from
   294 specifications; specific support for HOL constructs such as inductive
   295 datatypes and sets, as well as recursive functions; can be invoked
   296 via 'generate_code' theory section;
   297 
   298 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   299 
   300 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   301 (beware of argument permutation!);
   302 
   303 * HOL: linorder_less_split superseded by linorder_cases;
   304 
   305 * HOL/List: "nodups" renamed to "distinct";
   306 
   307 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   308 to peripheral theory "Hilbert_Choice";
   309 
   310 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   311 in this (rare) case use:
   312 
   313   delSWrapper "split_all_tac"
   314   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   315 
   316 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   317 MAY FAIL;
   318 
   319 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   320 Isabelle's type classes, ^ on functions and relations has too general
   321 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   322 necessary to attach explicit type constraints;
   323 
   324 * HOL/Relation: the prefix name of the infix "O" has been changed from
   325 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   326 renamed accordingly (eg "compI" -> "rel_compI").
   327 
   328 * HOL: syntax translations now work properly with numerals and records
   329 expressions;
   330 
   331 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   332 of "lam" -- INCOMPATIBILITY;
   333 
   334 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   335 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   336 renamed "Product_Type.unit";
   337 
   338 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   339 
   340 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   341 the "cases" method);
   342 
   343 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   344 Florian Kammüller);
   345 
   346 * HOL/IMP: updated and converted to new-style theory format; several
   347 parts turned into readable document, with proper Isar proof texts and
   348 some explanations (by Gerwin Klein);
   349 
   350 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   351 
   352 * HOL-Hyperreal is now a logic image;
   353 
   354 
   355 *** HOLCF ***
   356 
   357 * Isar: consts/constdefs supports mixfix syntax for continuous
   358 operations;
   359 
   360 * Isar: domain package adapted to new-style theory format, e.g. see
   361 HOLCF/ex/Dnat.thy;
   362 
   363 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   364 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   365 lift.induct_tac, always use UU instead of Undef;
   366 
   367 * HOLCF/IMP: updated and converted to new-style theory;
   368 
   369 
   370 *** ZF ***
   371 
   372 * Isar: proper integration of logic-specific tools and packages,
   373 including theory commands '(co)inductive', '(co)datatype',
   374 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   375 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   376 
   377 * theory Main no longer includes AC; for the Axiom of Choice, base
   378 your theory on Main_ZFC;
   379 
   380 * the integer library now covers quotients and remainders, with many
   381 laws relating division to addition, multiplication, etc.;
   382 
   383 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   384 typeless version of the formalism;
   385 
   386 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   387 format;
   388 
   389 * ZF/Induct: new directory for examples of inductive definitions,
   390 including theory Multiset for multiset orderings; converted to
   391 new-style theory format;
   392 
   393 * ZF: many new theorems about lists, ordinals, etc.;
   394 
   395 
   396 *** General ***
   397 
   398 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   399 variable proof controls level of detail: 0 = no proofs (only oracle
   400 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   401 also ref manual for further ML interfaces;
   402 
   403 * Pure/axclass: removed obsolete ML interface
   404 goal_subclass/goal_arity;
   405 
   406 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   407 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   408 separate tokens, so expressions involving minus need to be spaced
   409 properly;
   410 
   411 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   412 rather than "infixl" or "infixr";
   413 
   414 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   415 sort constraint specifications in type inference; e.g. "x::_::foo"
   416 ensures that the type of "x" is of sort "foo" (but not necessarily a
   417 type variable);
   418 
   419 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   420 control output of nested => (types); the default behavior is
   421 "type_brackets";
   422 
   423 * Pure/syntax: builtin parse translation for "_constify" turns valued
   424 tokens into AST constants;
   425 
   426 * Pure/syntax: prefer later declarations of translations and print
   427 translation functions; potential INCOMPATIBILITY: need to reverse
   428 multiple declarations for same syntax element constant;
   429 
   430 * Pure/show_hyps reset by default (in accordance to existing Isar
   431 practice);
   432 
   433 * Provers/classical: renamed addaltern to addafter, addSaltern to
   434 addSafter;
   435 
   436 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   437 as well;
   438 
   439 * system: tested support for MacOS X; should be able to get Isabelle +
   440 Proof General to work in a plain Terminal after installing Poly/ML
   441 (e.g. from the Isabelle distribution area) and GNU bash alone
   442 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   443 support requires further installations, e.g. from
   444 http://fink.sourceforge.net/);
   445 
   446 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   447 
   448 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   449 of 40 MB), cf. ML_OPTIONS;
   450 
   451 * system: Proof General keywords specification is now part of the
   452 Isabelle distribution (see etc/isar-keywords.el);
   453 
   454 * system: support for persistent Proof General sessions (refrain from
   455 outdating all loaded theories on startup); user may create writable
   456 logic images like this: ``isabelle -q HOL Test'';
   457 
   458 * system: smart selection of Isabelle process versus Isabelle
   459 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   460 run both "isabelle" and "Isabelle" even if file names are badly
   461 damaged (executable inspects the case of the first letter of its own
   462 name); added separate "isabelle-process" and "isabelle-interface";
   463 
   464 * system: refrain from any attempt at filtering input streams; no
   465 longer support ``8bit'' encoding of old isabelle font, instead proper
   466 iso-latin characters may now be used; the related isatools
   467 "symbolinput" and "nonascii" have disappeared as well;
   468 
   469 * system: removed old "xterm" interface (the print modes "xterm" and
   470 "xterm_color" are still available for direct use in a suitable
   471 terminal);
   472 
   473 
   474 
   475 New in Isabelle99-2 (February 2001)
   476 -----------------------------------
   477 
   478 *** Overview of INCOMPATIBILITIES ***
   479 
   480 * HOL: please note that theories in the Library and elsewhere often use the
   481 new-style (Isar) format; to refer to their theorems in an ML script you must
   482 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   483 
   484 * HOL: inductive package no longer splits induction rule aggressively,
   485 but only as far as specified by the introductions given; the old
   486 format may be recovered via ML function complete_split_rule or attribute
   487 'split_rule (complete)';
   488 
   489 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   490 gfp_Tarski to gfp_unfold;
   491 
   492 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   493 
   494 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   495 relation); infix "^^" has been renamed "``"; infix "``" has been
   496 renamed "`"; "univalent" has been renamed "single_valued";
   497 
   498 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   499 operation;
   500 
   501 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   502 
   503 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   504 
   505 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   506 consequence, it is no longer monotonic wrt. the local goal context
   507 (which is now passed through the inductive cases);
   508 
   509 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   510 \<gg> to \<ggreater>;
   511 
   512 
   513 *** Document preparation ***
   514 
   515 * \isabellestyle{NAME} selects version of Isabelle output (currently
   516 available: are "it" for near math-mode best-style output, "sl" for
   517 slanted text style, and "tt" for plain type-writer; if no
   518 \isabellestyle command is given, output is according to slanted
   519 type-writer);
   520 
   521 * support sub/super scripts (for single symbols only), input syntax is
   522 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   523 
   524 * some more standard symbols; see Appendix A of the system manual for
   525 the complete list of symbols defined in isabellesym.sty;
   526 
   527 * improved isabelle style files; more abstract symbol implementation
   528 (should now use \isamath{...} and \isatext{...} in custom symbol
   529 definitions);
   530 
   531 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   532 state; Note that presentation of goal states does not conform to
   533 actual human-readable proof documents.  Please do not include goal
   534 states into document output unless you really know what you are doing!
   535 
   536 * proper indentation of antiquoted output with proportional LaTeX
   537 fonts;
   538 
   539 * no_document ML operator temporarily disables LaTeX document
   540 generation;
   541 
   542 * isatool unsymbolize tunes sources for plain ASCII communication;
   543 
   544 
   545 *** Isar ***
   546 
   547 * Pure: Isar now suffers initial goal statements to contain unbound
   548 schematic variables (this does not conform to actual readable proof
   549 documents, due to unpredictable outcome and non-compositional proof
   550 checking); users who know what they are doing may use schematic goals
   551 for Prolog-style synthesis of proven results;
   552 
   553 * Pure: assumption method (an implicit finishing) now handles actual
   554 rules as well;
   555 
   556 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   557 initial goal, declare "that" only as Pure intro (only for single
   558 steps); the "that" rule assumption may now be involved in implicit
   559 finishing, thus ".." becomes a feasible for trivial obtains;
   560 
   561 * Pure: default proof step now includes 'intro_classes'; thus trivial
   562 instance proofs may be performed by "..";
   563 
   564 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   565 statements as well;
   566 
   567 * Pure: more robust selection of calculational rules;
   568 
   569 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   570 rule (as well as the assumption rule);
   571 
   572 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   573 lemmas, using the graph browser tool;
   574 
   575 * Pure: predict failure of "show" in interactive mode;
   576 
   577 * Pure: 'thms_containing' now takes actual terms as arguments;
   578 
   579 * HOL: improved method 'induct' --- now handles non-atomic goals
   580 (potential INCOMPATIBILITY); tuned error handling;
   581 
   582 * HOL: cases and induct rules now provide explicit hints about the
   583 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   584 any remaining facts are inserted into the goal verbatim;
   585 
   586 * HOL: local contexts (aka cases) may now contain term bindings as
   587 well; the 'cases' and 'induct' methods new provide a ?case binding for
   588 the result to be shown in each case;
   589 
   590 * HOL: added 'recdef_tc' command;
   591 
   592 * isatool convert assists in eliminating legacy ML scripts;
   593 
   594 
   595 *** HOL ***
   596 
   597 * HOL/Library: a collection of generic theories to be used together
   598 with main HOL; the theory loader path already includes this directory
   599 by default; the following existing theories have been moved here:
   600 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   601 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   602 
   603 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   604 modelling and verification task performed in Isabelle/HOL +
   605 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   606 
   607 * HOL/Algebra: special summation operator SUM no longer exists, it has
   608 been replaced by setsum; infix 'assoc' now has priority 50 (like
   609 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   610 'domain', this makes the theory consistent with mathematical
   611 literature;
   612 
   613 * HOL basics: added overloaded operations "inverse" and "divide"
   614 (infix "/"), syntax for generic "abs" operation, generic summation
   615 operator \<Sum>;
   616 
   617 * HOL/typedef: simplified package, provide more useful rules (see also
   618 HOL/subset.thy);
   619 
   620 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   621 now expressed as a proper nested rule (old-style tactic scripts may
   622 require atomize_strip_tac to cope with non-atomic premises);
   623 
   624 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   625 to "split_conv" (old name still available for compatibility);
   626 
   627 * HOL: improved concrete syntax for strings (e.g. allows translation
   628 rules with string literals);
   629 
   630 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   631  and Fleuriot's mechanization of analysis, including the transcendental
   632  functions for the reals;
   633 
   634 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   635 
   636 
   637 *** CTT ***
   638 
   639 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   640 "lam" is displayed as TWO lambda-symbols
   641 
   642 * CTT: theory Main now available, containing everything (that is, Bool
   643 and Arith);
   644 
   645 
   646 *** General ***
   647 
   648 * Pure: the Simplifier has been implemented properly as a derived rule
   649 outside of the actual kernel (at last!); the overall performance
   650 penalty in practical applications is about 50%, while reliability of
   651 the Isabelle inference kernel has been greatly improved;
   652 
   653 * print modes "brackets" and "no_brackets" control output of nested =>
   654 (types) and ==> (props); the default behaviour is "brackets";
   655 
   656 * Provers: fast_tac (and friends) now handle actual object-logic rules
   657 as assumptions as well;
   658 
   659 * system: support Poly/ML 4.0;
   660 
   661 * system: isatool install handles KDE version 1 or 2;
   662 
   663 
   664 
   665 New in Isabelle99-1 (October 2000)
   666 ----------------------------------
   667 
   668 *** Overview of INCOMPATIBILITIES ***
   669 
   670 * HOL: simplification of natural numbers is much changed; to partly
   671 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   672 issue the following ML commands:
   673 
   674   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   675   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   676 
   677 * HOL: simplification no longer dives into case-expressions; this is
   678 controlled by "t.weak_case_cong" for each datatype t;
   679 
   680 * HOL: nat_less_induct renamed to less_induct;
   681 
   682 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   683 fixsome to patch .thy and .ML sources automatically;
   684 
   685   select_equality  -> some_equality
   686   select_eq_Ex     -> some_eq_ex
   687   selectI2EX       -> someI2_ex
   688   selectI2         -> someI2
   689   selectI          -> someI
   690   select1_equality -> some1_equality
   691   Eps_sym_eq       -> some_sym_eq_trivial
   692   Eps_eq           -> some_eq_trivial
   693 
   694 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   695 
   696 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   697 instead);
   698 
   699 * HOL: the recursion equations generated by 'recdef' are now called
   700 f.simps instead of f.rules;
   701 
   702 * HOL: qed_spec_mp now also handles bounded ALL as well;
   703 
   704 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   705 sometimes be needed;
   706 
   707 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   708 
   709 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   710 
   711 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   712 product is now "<*>" instead of "Times"; the lexicographic product is
   713 now "<*lex*>" instead of "**";
   714 
   715 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   716 of main HOL, but was unused); better use HOL's datatype package;
   717 
   718 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   719 the old syntax may be recovered as follows:
   720 
   721   syntax (symbols)
   722     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   723       (infixl "\\<oplus>" 100)
   724 
   725 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   726 
   727 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   728 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   729 internally;
   730 
   731 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   732 changed from A/r to A//r;
   733 
   734 * ZF: new treatment of arithmetic (nat & int) may break some old
   735 proofs;
   736 
   737 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   738 rulify -> rule_format, elimify -> elim_format, ...);
   739 
   740 * Isar/Provers: intro/elim/dest attributes changed; renamed
   741 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   742 should have to change intro!! to intro? only); replaced "delrule" by
   743 "rule del";
   744 
   745 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   746 
   747 * Provers: strengthened force_tac by using new first_best_tac;
   748 
   749 * LaTeX document preparation: several changes of isabelle.sty (see
   750 lib/texinputs);
   751 
   752 
   753 *** Document preparation ***
   754 
   755 * formal comments (text blocks etc.) in new-style theories may now
   756 contain antiquotations of thm/prop/term/typ/text to be presented
   757 according to latex print mode; concrete syntax is like this:
   758 @{term[show_types] "f(x) = a + x"};
   759 
   760 * isatool mkdir provides easy setup of Isabelle session directories,
   761 including proper document sources;
   762 
   763 * generated LaTeX sources are now deleted after successful run
   764 (isatool document -c); may retain a copy somewhere else via -D option
   765 of isatool usedir;
   766 
   767 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   768 style files, achieving self-contained LaTeX sources and simplifying
   769 LaTeX debugging;
   770 
   771 * old-style theories now produce (crude) LaTeX output as well;
   772 
   773 * browser info session directories are now self-contained (may be put
   774 on WWW server seperately); improved graphs of nested sessions; removed
   775 graph for 'all sessions';
   776 
   777 * several improvements in isabelle style files; \isabellestyle{it}
   778 produces fake math mode output; \isamarkupheader is now \section by
   779 default; see lib/texinputs/isabelle.sty etc.;
   780 
   781 
   782 *** Isar ***
   783 
   784 * Isar/Pure: local results and corresponding term bindings are now
   785 subject to Hindley-Milner polymorphism (similar to ML); this
   786 accommodates incremental type-inference very nicely;
   787 
   788 * Isar/Pure: new derived language element 'obtain' supports
   789 generalized existence reasoning;
   790 
   791 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   792 support accumulation of results, without applying any rules yet;
   793 useful to collect intermediate results without explicit name
   794 references, and for use with transitivity rules with more than 2
   795 premises;
   796 
   797 * Isar/Pure: scalable support for case-analysis type proofs: new
   798 'case' language element refers to local contexts symbolically, as
   799 produced by certain proof methods; internally, case names are attached
   800 to theorems as "tags";
   801 
   802 * Isar/Pure: theory command 'hide' removes declarations from
   803 class/type/const name spaces;
   804 
   805 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   806 indicate potential overloading;
   807 
   808 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   809 
   810 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   811 "{a,b,c}" instead of {a,b,c};
   812 
   813 * Isar/Pure now provides its own version of intro/elim/dest
   814 attributes; useful for building new logics, but beware of confusion
   815 with the version in Provers/classical;
   816 
   817 * Isar/Pure: the local context of (non-atomic) goals is provided via
   818 case name 'antecedent';
   819 
   820 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   821 to the current context is now done automatically);
   822 
   823 * Isar/Pure: theory command 'method_setup' provides a simple interface
   824 for definining proof methods in ML;
   825 
   826 * Isar/Provers: intro/elim/dest attributes changed; renamed
   827 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   828 most cases, one should have to change intro!! to intro? only);
   829 replaced "delrule" by "rule del";
   830 
   831 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   832 'symmetric' attribute (the latter supercedes [RS sym]);
   833 
   834 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   835 method modifier); 'simp' method: 'only:' modifier removes loopers as
   836 well (including splits);
   837 
   838 * Isar/Provers: Simplifier and Classical methods now support all kind
   839 of modifiers used in the past, including 'cong', 'iff', etc.
   840 
   841 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   842 of Simplifier and Classical reasoner);
   843 
   844 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   845 now support named cases; major packages (inductive, datatype, primrec,
   846 recdef) support case names and properly name parameters;
   847 
   848 * Isar/HOL: new transitivity rules for substitution in inequalities --
   849 monotonicity conditions are extracted to be proven at end of
   850 calculations;
   851 
   852 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   853 method anyway;
   854 
   855 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   856 split_if split_if_asm; datatype package provides theorems foo.splits =
   857 foo.split foo.split_asm for each datatype;
   858 
   859 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   860 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   861 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   862 use "(cases (simplified))" method in proper proof texts);
   863 
   864 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   865 
   866 * Isar: names of theorems etc. may be natural numbers as well;
   867 
   868 * Isar: 'pr' command: optional arguments for goals_limit and
   869 ProofContext.prems_limit; no longer prints theory contexts, but only
   870 proof states;
   871 
   872 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   873 additional print modes to be specified; e.g. "pr(latex)" will print
   874 proof state according to the Isabelle LaTeX style;
   875 
   876 * Isar: improved support for emulating tactic scripts, including proof
   877 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   878 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   879 (for HOL datatypes);
   880 
   881 * Isar: simplified (more robust) goal selection of proof methods: 1st
   882 goal, all goals, or explicit goal specifier (tactic emulation); thus
   883 'proof method scripts' have to be in depth-first order;
   884 
   885 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   886 
   887 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   888 should instead use individual commands for printing items
   889 (print_commands, print_methods etc.);
   890 
   891 * Isar: added 'nothing' --- the empty list of theorems;
   892 
   893 
   894 *** HOL ***
   895 
   896 * HOL/MicroJava: formalization of a fragment of Java, together with a
   897 corresponding virtual machine and a specification of its bytecode
   898 verifier and a lightweight bytecode verifier, including proofs of
   899 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   900 Cornelia Pusch (see also the homepage of project Bali at
   901 http://isabelle.in.tum.de/Bali/);
   902 
   903 * HOL/Algebra: new theory of rings and univariate polynomials, by
   904 Clemens Ballarin;
   905 
   906 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   907 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   908 Rasmussen;
   909 
   910 * HOL/Lattice: fundamental concepts of lattice theory and order
   911 structures, including duals, properties of bounds versus algebraic
   912 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   913 Theorem for complete lattices etc.; may also serve as a demonstration
   914 for abstract algebraic reasoning using axiomatic type classes, and
   915 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   916 
   917 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   918 von Oheimb;
   919 
   920 * HOL/IMPP: extension of IMP with local variables and mutually
   921 recursive procedures, by David von Oheimb;
   922 
   923 * HOL/Lambda: converted into new-style theory and document;
   924 
   925 * HOL/ex/Multiquote: example of multiple nested quotations and
   926 anti-quotations -- basically a generalized version of de-Bruijn
   927 representation; very useful in avoiding lifting of operations;
   928 
   929 * HOL/record: added general record equality rule to simpset; fixed
   930 select-update simplification procedure to handle extended records as
   931 well; admit "r" as field name;
   932 
   933 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   934 other numeric types and also as the identity of groups, rings, etc.;
   935 
   936 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   937 Types nat and int belong to this axclass;
   938 
   939 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   940    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   941    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   942   two terms #m*u and #n*u are replaced by #(m+n)*u
   943     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   944   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   945     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   946 
   947 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   948 powerful prover for predicate logic but knows nothing of clasets; see
   949 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   950 
   951 * HOL: new version of "case_tac" subsumes both boolean case split and
   952 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   953 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   954 
   955 * HOL: simplification no longer dives into case-expressions: only the
   956 selector expression is simplified, but not the remaining arms; to
   957 enable full simplification of case-expressions for datatype t, you may
   958 remove t.weak_case_cong from the simpset, either globally (Delcongs
   959 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   960 
   961 * HOL/recdef: the recursion equations generated by 'recdef' for
   962 function 'f' are now called f.simps instead of f.rules; if all
   963 termination conditions are proved automatically, these simplification
   964 rules are added to the simpset, as in primrec; rules may be named
   965 individually as well, resulting in a separate list of theorems for
   966 each equation;
   967 
   968 * HOL/While is a new theory that provides a while-combinator. It
   969 permits the definition of tail-recursive functions without the
   970 provision of a termination measure. The latter is necessary once the
   971 invariant proof rule for while is applied.
   972 
   973 * HOL: new (overloaded) notation for the set of elements below/above
   974 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   975 
   976 * HOL: theorems impI, allI, ballI bound as "strip";
   977 
   978 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   979 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   980 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   981 
   982 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   983 
   984 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   985 main HOL, but was unused);
   986 
   987 * HOL: fewer consts declared as global (e.g. have to refer to
   988 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   989 
   990 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   991 in case of overlap with user translations (e.g. judgements over
   992 tuples); (note that the underlying logical represenation is still
   993 bogus);
   994 
   995 
   996 *** ZF ***
   997 
   998 * ZF: simplification automatically cancels common terms in arithmetic
   999 expressions over nat and int;
  1000 
  1001 * ZF: new treatment of nat to minimize type-checking: all operators
  1002 coerce their operands to a natural number using the function natify,
  1003 making the algebraic laws unconditional;
  1004 
  1005 * ZF: as above, for int: operators coerce their operands to an integer
  1006 using the function intify;
  1007 
  1008 * ZF: the integer library now contains many of the usual laws for the
  1009 orderings, including $<=, and monotonicity laws for $+ and $*;
  1010 
  1011 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1012 simplification;
  1013 
  1014 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1015 to the simplifier and classical reasoner simultaneously;
  1016 
  1017 
  1018 *** General ***
  1019 
  1020 * Provers: blast_tac now handles actual object-logic rules as
  1021 assumptions; note that auto_tac uses blast_tac internally as well;
  1022 
  1023 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1024 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1025 
  1026 * Provers: delrules now handles destruct rules as well (no longer need
  1027 explicit make_elim);
  1028 
  1029 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1030   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1031 use instead the strong form,
  1032   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1033 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1034 from destruct-rules;
  1035 
  1036 * Provers: Simplifier.easy_setup provides a fast path to basic
  1037 Simplifier setup for new object-logics;
  1038 
  1039 * Pure: AST translation rules no longer require constant head on LHS;
  1040 
  1041 * Pure: improved name spaces: ambiguous output is qualified; support
  1042 for hiding of names;
  1043 
  1044 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1045 XSYMBOL_HOME; no longer need to do manual configuration in most
  1046 situations;
  1047 
  1048 * system: compression of ML heaps images may now be controlled via -c
  1049 option of isabelle and isatool usedir (currently only observed by
  1050 Poly/ML);
  1051 
  1052 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1053 useful for remote X11);
  1054 
  1055 * system: provide TAGS file for Isabelle sources;
  1056 
  1057 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1058 order;
  1059 
  1060 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1061 timing flag supersedes proof_timing and Toplevel.trace;
  1062 
  1063 * ML: new combinators |>> and |>>> for incremental transformations
  1064 with secondary results (e.g. certain theory extensions):
  1065 
  1066 * ML: PureThy.add_defs gets additional argument to indicate potential
  1067 overloading (usually false);
  1068 
  1069 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1070 results;
  1071 
  1072 
  1073 
  1074 New in Isabelle99 (October 1999)
  1075 --------------------------------
  1076 
  1077 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1078 
  1079 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1080 are no longer simplified.  (This allows the simplifier to unfold recursive
  1081 functional programs.)  To restore the old behaviour, declare
  1082 
  1083     Delcongs [if_weak_cong];
  1084 
  1085 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1086 complement;
  1087 
  1088 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1089 
  1090 * HOL/datatype: mutual_induct_tac no longer exists --
  1091   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1092 
  1093 * HOL/typedef: fixed type inference for representing set; type
  1094 arguments now have to occur explicitly on the rhs as type constraints;
  1095 
  1096 * ZF: The con_defs part of an inductive definition may no longer refer
  1097 to constants declared in the same theory;
  1098 
  1099 * HOL, ZF: the function mk_cases, generated by the inductive
  1100 definition package, has lost an argument.  To simplify its result, it
  1101 uses the default simpset instead of a supplied list of theorems.
  1102 
  1103 * HOL/List: the constructors of type list are now Nil and Cons;
  1104 
  1105 * Simplifier: the type of the infix ML functions
  1106         setSSolver addSSolver setSolver addSolver
  1107 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1108 for packaging solvers. A solver is created via
  1109         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1110 where the string argument is only a comment.
  1111 
  1112 
  1113 *** Proof tools ***
  1114 
  1115 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1116 decision procedure for linear arithmetic. Currently it is used for
  1117 types `nat', `int', and `real' in HOL (see below); it can, should and
  1118 will be instantiated for other types and logics as well.
  1119 
  1120 * The simplifier now accepts rewrite rules with flexible heads, eg
  1121      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1122   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1123   matching.
  1124 
  1125 
  1126 *** General ***
  1127 
  1128 * New Isabelle/Isar subsystem provides an alternative to traditional
  1129 tactical theorem proving; together with the ProofGeneral/isar user
  1130 interface it offers an interactive environment for developing human
  1131 readable proof documents (Isar == Intelligible semi-automated
  1132 reasoning); for further information see isatool doc isar-ref,
  1133 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1134 
  1135 * improved and simplified presentation of theories: better HTML markup
  1136 (including colors), graph views in several sizes; isatool usedir now
  1137 provides a proper interface for user theories (via -P option); actual
  1138 document preparation based on (PDF)LaTeX is available as well (for
  1139 new-style theories only); see isatool doc system for more information;
  1140 
  1141 * native support for Proof General, both for classic Isabelle and
  1142 Isabelle/Isar;
  1143 
  1144 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1145 using the graph browser tool;
  1146 
  1147 * Isabelle manuals now also available as PDF;
  1148 
  1149 * theory loader rewritten from scratch (may not be fully
  1150 bug-compatible); old loadpath variable has been replaced by show_path,
  1151 add_path, del_path, reset_path functions; new operations such as
  1152 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1153 isatool doc ref);
  1154 
  1155 * improved isatool install: option -k creates KDE application icon,
  1156 option -p DIR installs standalone binaries;
  1157 
  1158 * added ML_PLATFORM setting (useful for cross-platform installations);
  1159 more robust handling of platform specific ML images for SML/NJ;
  1160 
  1161 * the settings environment is now statically scoped, i.e. it is never
  1162 created again in sub-processes invoked from isabelle, isatool, or
  1163 Isabelle;
  1164 
  1165 * path element specification '~~' refers to '$ISABELLE_HOME';
  1166 
  1167 * in locales, the "assumes" and "defines" parts may be omitted if
  1168 empty;
  1169 
  1170 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1171 long arrows);
  1172 
  1173 * new print_mode "HTML";
  1174 
  1175 * new flag show_tags controls display of tags of theorems (which are
  1176 basically just comments that may be attached by some tools);
  1177 
  1178 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1179 mode and goal output format:
  1180 
  1181 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1182 244c244
  1183 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1184 ---
  1185 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1186 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1187 181c181
  1188 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1189 ---
  1190 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1191 
  1192 * function bind_thms stores lists of theorems (cf. bind_thm);
  1193 
  1194 * new shorthand tactics ftac, eatac, datac, fatac;
  1195 
  1196 * qed (and friends) now accept "" as result name; in that case the
  1197 theorem is not stored, but proper checks and presentation of the
  1198 result still apply;
  1199 
  1200 * theorem database now also indexes constants "Trueprop", "all",
  1201 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1202 
  1203 
  1204 *** HOL ***
  1205 
  1206 ** HOL arithmetic **
  1207 
  1208 * There are now decision procedures for linear arithmetic over nat and
  1209 int:
  1210 
  1211 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1212 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1213 are treated as atomic; subformulae not involving type `nat' or `int'
  1214 are ignored; quantified subformulae are ignored unless they are
  1215 positive universal or negative existential. The tactic has to be
  1216 invoked by hand and can be a little bit slow. In particular, the
  1217 running time is exponential in the number of occurrences of `min' and
  1218 `max', and `-' on `nat'.
  1219 
  1220 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1221 (negated) (in)equalities among the premises and the conclusion into
  1222 account (i.e. no compound formulae) and does not know about `min' and
  1223 `max', and `-' on `nat'. It is fast and is used automatically by the
  1224 simplifier.
  1225 
  1226 NB: At the moment, these decision procedures do not cope with mixed
  1227 nat/int formulae where the two parts interact, such as `m < n ==>
  1228 int(m) < int(n)'.
  1229 
  1230 * HOL/Numeral provides a generic theory of numerals (encoded
  1231 efficiently as bit strings); setup for types nat/int/real is in place;
  1232 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1233 int, existing theories and proof scripts may require a few additional
  1234 type constraints;
  1235 
  1236 * integer division and remainder can now be performed on constant
  1237 arguments;
  1238 
  1239 * many properties of integer multiplication, division and remainder
  1240 are now available;
  1241 
  1242 * An interface to the Stanford Validity Checker (SVC) is available through the
  1243 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1244 are proved automatically.  SVC must be installed separately, and its results
  1245 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1246 invocation of the underlying oracle).  For SVC see
  1247   http://verify.stanford.edu/SVC
  1248 
  1249 * IsaMakefile: the HOL-Real target now builds an actual image;
  1250 
  1251 
  1252 ** HOL misc **
  1253 
  1254 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1255 (in Isabelle/Isar) -- by Gertrud Bauer;
  1256 
  1257 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1258 analysis for assembly languages with subtypes;
  1259 
  1260 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1261 -- avoids syntactic ambiguities and treats state, transition, and
  1262 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1263 changed syntax and (many) tactics;
  1264 
  1265 * HOL/inductive: Now also handles more general introduction rules such
  1266   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1267   theorems are now maintained within the theory (maintained via the
  1268   "mono" attribute);
  1269 
  1270 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1271   (using function types) such as
  1272 
  1273   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1274 
  1275 * HOL/record: record_simproc (part of the default simpset) takes care
  1276 of selectors applied to updated records; record_split_tac is no longer
  1277 part of the default claset; update_defs may now be removed from the
  1278 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1279 
  1280   claset_ref () := claset() addSWrapper record_split_wrapper;
  1281   Delsimprocs [record_simproc]
  1282 
  1283 * HOL/typedef: fixed type inference for representing set; type
  1284 arguments now have to occur explicitly on the rhs as type constraints;
  1285 
  1286 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1287 names rather than an ML expression;
  1288 
  1289 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1290 supplied later.  Program schemes can be defined, such as
  1291     "While B C s = (if B s then While B C (C s) else s)"
  1292 where the well-founded relation can be chosen after B and C have been given.
  1293 
  1294 * HOL/List: the constructors of type list are now Nil and Cons;
  1295 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1296 course, ML tools referring to List.list.op # etc. have to be adapted;
  1297 
  1298 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1299 disabled by default; run isabelle with option -m HOL to get back to
  1300 the original Gordon/HOL-style output;
  1301 
  1302 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1303 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1304 
  1305 * HOL basic syntax simplified (more orthogonal): all variants of
  1306 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1307 Eps operator is provided as well: "SOME x. P[x]";
  1308 
  1309 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1310 
  1311 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1312 thus available for user theories;
  1313 
  1314 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1315 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1316 time;
  1317 
  1318 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1319 several times and then mp;
  1320 
  1321 
  1322 *** LK ***
  1323 
  1324 * the notation <<...>> is now available as a notation for sequences of
  1325 formulas;
  1326 
  1327 * the simplifier is now installed
  1328 
  1329 * the axiom system has been generalized (thanks to Soren Heilmann)
  1330 
  1331 * the classical reasoner now has a default rule database
  1332 
  1333 
  1334 *** ZF ***
  1335 
  1336 * new primrec section allows primitive recursive functions to be given
  1337 directly (as in HOL) over datatypes and the natural numbers;
  1338 
  1339 * new tactics induct_tac and exhaust_tac for induction (or case
  1340 analysis) over datatypes and the natural numbers;
  1341 
  1342 * the datatype declaration of type T now defines the recursor T_rec;
  1343 
  1344 * simplification automatically does freeness reasoning for datatype
  1345 constructors;
  1346 
  1347 * automatic type-inference, with AddTCs command to insert new
  1348 type-checking rules;
  1349 
  1350 * datatype introduction rules are now added as Safe Introduction rules
  1351 to the claset;
  1352 
  1353 * the syntax "if P then x else y" is now available in addition to
  1354 if(P,x,y);
  1355 
  1356 
  1357 *** Internal programming interfaces ***
  1358 
  1359 * tuned simplifier trace output; new flag debug_simp;
  1360 
  1361 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1362 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1363 
  1364 * AxClass.axclass_tac lost the theory argument;
  1365 
  1366 * tuned current_goals_markers semantics: begin / end goal avoids
  1367 printing empty lines;
  1368 
  1369 * removed prs and prs_fn hook, which was broken because it did not
  1370 include \n in its semantics, forcing writeln to add one
  1371 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1372 string -> unit if you really want to output text without newline;
  1373 
  1374 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1375 plain output, interface builders may have to enable 'isabelle_font'
  1376 mode to get Isabelle font glyphs as before;
  1377 
  1378 * refined token_translation interface; INCOMPATIBILITY: output length
  1379 now of type real instead of int;
  1380 
  1381 * theory loader actions may be traced via new ThyInfo.add_hook
  1382 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1383 your own database of information attached to *whole* theories -- as
  1384 opposed to intra-theory data slots offered via TheoryDataFun;
  1385 
  1386 * proper handling of dangling sort hypotheses (at last!);
  1387 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1388 extra sort hypotheses that can be witnessed from the type signature;
  1389 the force_strip_shyps flag is gone, any remaining shyps are simply
  1390 left in the theorem (with a warning issued by strip_shyps_warning);
  1391 
  1392 
  1393 
  1394 New in Isabelle98-1 (October 1998)
  1395 ----------------------------------
  1396 
  1397 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1398 
  1399 * several changes of automated proof tools;
  1400 
  1401 * HOL: major changes to the inductive and datatype packages, including
  1402 some minor incompatibilities of theory syntax;
  1403 
  1404 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1405 called `inj_on';
  1406 
  1407 * HOL: removed duplicate thms in Arith:
  1408   less_imp_add_less  should be replaced by  trans_less_add1
  1409   le_imp_add_le      should be replaced by  trans_le_add1
  1410 
  1411 * HOL: unary minus is now overloaded (new type constraints may be
  1412 required);
  1413 
  1414 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1415 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1416 now taken as an integer constant.
  1417 
  1418 * Pure: ML function 'theory_of' renamed to 'theory';
  1419 
  1420 
  1421 *** Proof tools ***
  1422 
  1423 * Simplifier:
  1424   1. Asm_full_simp_tac is now more aggressive.
  1425      1. It will sometimes reorient premises if that increases their power to
  1426         simplify.
  1427      2. It does no longer proceed strictly from left to right but may also
  1428         rotate premises to achieve further simplification.
  1429      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1430      old Asm_full_simp_tac in that it does not rotate premises.
  1431   2. The simplifier now knows a little bit about nat-arithmetic.
  1432 
  1433 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1434 allows for selected deletion of wrappers, by introduction of names for
  1435 wrapper functionals.  This implies that addbefore, addSbefore,
  1436 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1437 and that adding two tactics with the same name overwrites the first
  1438 one (emitting a warning).
  1439   type wrapper = (int -> tactic) -> (int -> tactic)
  1440   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1441   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1442   delWrapper, delSWrapper: claset *  string            -> claset
  1443   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1444 
  1445 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1446 semantics; addbefore now affects only the unsafe part of step_tac
  1447 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1448 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1449 by Force_tac;
  1450 
  1451 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1452 compWrapper; added safe wrapper (and access functions for it);
  1453 
  1454 * HOL/split_all_tac is now much faster and fails if there is nothing
  1455 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1456 and the names of the automatically generated variables have changed.
  1457 split_all_tac has moved within claset() from unsafe wrappers to safe
  1458 wrappers, which means that !!-bound variables are split much more
  1459 aggressively, and safe_tac and clarify_tac now split such variables.
  1460 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1461 Note: the same holds for record_split_tac, which does the job of
  1462 split_all_tac for record fields.
  1463 
  1464 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1465 permanently to the default simpset using Addsplits just like
  1466 Addsimps. They can be removed via Delsplits just like
  1467 Delsimps. Lower-case versions are also available.
  1468 
  1469 * HOL/Simplifier: The rule split_if is now part of the default
  1470 simpset. This means that the simplifier will eliminate all occurrences
  1471 of if-then-else in the conclusion of a goal. To prevent this, you can
  1472 either remove split_if completely from the default simpset by
  1473 `Delsplits [split_if]' or remove it in a specific call of the
  1474 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1475 other case splitting rules to/from the default simpset: every datatype
  1476 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1477 t is the name of the datatype).
  1478 
  1479 * Classical reasoner / Simplifier combination: new force_tac (and
  1480 derivatives Force_tac, force) combines rewriting and classical
  1481 reasoning (and whatever other tools) similarly to auto_tac, but is
  1482 aimed to solve the given subgoal completely.
  1483 
  1484 
  1485 *** General ***
  1486 
  1487 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1488 and `goalw': the theory is no longer needed as an explicit argument -
  1489 the current theory context is used; assumptions are no longer returned
  1490 at the ML-level unless one of them starts with ==> or !!; it is
  1491 recommended to convert to these new commands using isatool fixgoal
  1492 (backup your sources first!);
  1493 
  1494 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1495 the current theory context, and 'theory' to lookup stored theories;
  1496 
  1497 * new theory section 'locale' for declaring constants, assumptions and
  1498 definitions that have local scope;
  1499 
  1500 * new theory section 'nonterminals' for purely syntactic types;
  1501 
  1502 * new theory section 'setup' for generic ML setup functions
  1503 (e.g. package initialization);
  1504 
  1505 * the distribution now includes Isabelle icons: see
  1506 lib/logo/isabelle-{small,tiny}.xpm;
  1507 
  1508 * isatool install - install binaries with absolute references to
  1509 ISABELLE_HOME/bin;
  1510 
  1511 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1512 
  1513 * print mode 'emacs' reserved for Isamode;
  1514 
  1515 * support multiple print (ast) translations per constant name;
  1516 
  1517 * theorems involving oracles are now printed with a suffixed [!];
  1518 
  1519 
  1520 *** HOL ***
  1521 
  1522 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1523 
  1524 * HOL/inductive package reorganized and improved: now supports mutual
  1525 definitions such as
  1526 
  1527   inductive EVEN ODD
  1528     intrs
  1529       null "0 : EVEN"
  1530       oddI "n : EVEN ==> Suc n : ODD"
  1531       evenI "n : ODD ==> Suc n : EVEN"
  1532 
  1533 new theorem list "elims" contains an elimination rule for each of the
  1534 recursive sets; inductive definitions now handle disjunctive premises
  1535 correctly (also ZF);
  1536 
  1537 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1538 "mutual_induct" no longer exists - the induction rule is always
  1539 contained in "induct";
  1540 
  1541 
  1542 * HOL/datatype package re-implemented and greatly improved: now
  1543 supports mutually recursive datatypes such as
  1544 
  1545   datatype
  1546     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1547             | SUM ('a aexp) ('a aexp)
  1548             | DIFF ('a aexp) ('a aexp)
  1549             | NUM 'a
  1550   and
  1551     'a bexp = LESS ('a aexp) ('a aexp)
  1552             | AND ('a bexp) ('a bexp)
  1553             | OR ('a bexp) ('a bexp)
  1554 
  1555 as well as indirectly recursive datatypes such as
  1556 
  1557   datatype
  1558     ('a, 'b) term = Var 'a
  1559                   | App 'b ((('a, 'b) term) list)
  1560 
  1561 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1562 induction on mutually / indirectly recursive datatypes.
  1563 
  1564 Primrec equations are now stored in theory and can be accessed via
  1565 <function_name>.simps.
  1566 
  1567 INCOMPATIBILITIES:
  1568 
  1569   - Theories using datatypes must now have theory Datatype as an
  1570     ancestor.
  1571   - The specific <typename>.induct_tac no longer exists - use the
  1572     generic induct_tac instead.
  1573   - natE has been renamed to nat.exhaust - use exhaust_tac
  1574     instead of res_inst_tac ... natE. Note that the variable
  1575     names in nat.exhaust differ from the names in natE, this
  1576     may cause some "fragile" proofs to fail.
  1577   - The theorems split_<typename>_case and split_<typename>_case_asm
  1578     have been renamed to <typename>.split and <typename>.split_asm.
  1579   - Since default sorts of type variables are now handled correctly,
  1580     some datatype definitions may have to be annotated with explicit
  1581     sort constraints.
  1582   - Primrec definitions no longer require function name and type
  1583     of recursive argument.
  1584 
  1585 Consider using isatool fixdatatype to adapt your theories and proof
  1586 scripts to the new package (backup your sources first!).
  1587 
  1588 
  1589 * HOL/record package: considerably improved implementation; now
  1590 includes concrete syntax for record types, terms, updates; theorems
  1591 for surjective pairing and splitting !!-bound record variables; proof
  1592 support is as follows:
  1593 
  1594   1) standard conversions (selectors or updates applied to record
  1595 constructor terms) are part of the standard simpset;
  1596 
  1597   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1598 made part of standard simpset and claset via addIffs;
  1599 
  1600   3) a tactic for record field splitting (record_split_tac) is part of
  1601 the standard claset (addSWrapper);
  1602 
  1603 To get a better idea about these rules you may retrieve them via
  1604 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1605 the name of your record type.
  1606 
  1607 The split tactic 3) conceptually simplifies by the following rule:
  1608 
  1609   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1610 
  1611 Thus any record variable that is bound by meta-all will automatically
  1612 blow up into some record constructor term, consequently the
  1613 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1614 solve record problems automatically.
  1615 
  1616 
  1617 * reorganized the main HOL image: HOL/Integ and String loaded by
  1618 default; theory Main includes everything;
  1619 
  1620 * automatic simplification of integer sums and comparisons, using cancellation;
  1621 
  1622 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1623 
  1624 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1625 
  1626 * many new identities for unions, intersections, set difference, etc.;
  1627 
  1628 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1629 called split_if, split_split, split_sum_case and split_nat_case (to go
  1630 with add/delsplits);
  1631 
  1632 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1633 (?x::unit) = (); this is made part of the default simpset, which COULD
  1634 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1635 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1636 unit_abs_eta_conv is added in order to counter the effect of
  1637 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1638 %u.f();
  1639 
  1640 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1641 makes more sense);
  1642 
  1643 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1644   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1645   disjointness reasoning but breaking a few old proofs.
  1646 
  1647 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1648 to 'converse' from 'inverse' (for compatibility with ZF and some
  1649 literature);
  1650 
  1651 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1652 the well-founded relation;
  1653 
  1654 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1655     Compl A.  The "Compl" syntax remains available as input syntax for this
  1656     release ONLY.
  1657 
  1658 * HOL/Update: new theory of function updates:
  1659     f(a:=b) == %x. if x=a then b else f x
  1660 may also be iterated as in f(a:=b,c:=d,...);
  1661 
  1662 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1663 
  1664 * HOL/List:
  1665   - new function list_update written xs[i:=v] that updates the i-th
  1666     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1667   - new function `upt' written [i..j(] which generates the list
  1668     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1669     bound write [i..j], which is a shorthand for [i..j+1(].
  1670   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1671 
  1672 * HOL/Arith:
  1673   - removed 'pred' (predecessor) function;
  1674   - generalized some theorems about n-1;
  1675   - many new laws about "div" and "mod";
  1676   - new laws about greatest common divisors (see theory ex/Primes);
  1677 
  1678 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1679 instead of "inverse";
  1680 
  1681 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1682   of the multiset ordering;
  1683 
  1684 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1685   (not included by default);
  1686 
  1687 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1688 
  1689 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1690   programs, i.e. different program variables may have different types.
  1691 
  1692 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1693   [previously, this check worked only if the rewrite rule was unconditional]
  1694   Now rew can involve either definitions or equalities (either == or =).
  1695 
  1696 
  1697 *** ZF ***
  1698 
  1699 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1700   only the theorems proved on ZF.ML;
  1701 
  1702 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1703   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1704   disjointness reasoning but breaking a few old proofs.
  1705 
  1706 * ZF/Update: new theory of function updates
  1707     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1708   may also be iterated as in f(a:=b,c:=d,...);
  1709 
  1710 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1711 
  1712 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1713   [previously, this check worked only if the rewrite rule was unconditional]
  1714   Now rew can involve either definitions or equalities (either == or =).
  1715 
  1716 * case_tac provided for compatibility with HOL
  1717     (like the old excluded_middle_tac, but with subgoals swapped)
  1718 
  1719 
  1720 *** Internal programming interfaces ***
  1721 
  1722 * Pure: several new basic modules made available for general use, see
  1723 also src/Pure/README;
  1724 
  1725 * improved the theory data mechanism to support encapsulation (data
  1726 kind name replaced by private Object.kind, acting as authorization
  1727 key); new type-safe user interface via functor TheoryDataFun; generic
  1728 print_data function becomes basically useless;
  1729 
  1730 * removed global_names compatibility flag -- all theory declarations
  1731 are qualified by default;
  1732 
  1733 * module Pure/Syntax now offers quote / antiquote translation
  1734 functions (useful for Hoare logic etc. with implicit dependencies);
  1735 see HOL/ex/Antiquote for an example use;
  1736 
  1737 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1738 cterm -> thm;
  1739 
  1740 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1741 subgoal;
  1742 
  1743 * Display.print_goals function moved to Locale.print_goals;
  1744 
  1745 * standard print function for goals supports current_goals_markers
  1746 variable for marking begin of proof, end of proof, start of goal; the
  1747 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1748 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1749 for example;
  1750 
  1751 
  1752 
  1753 New in Isabelle98 (January 1998)
  1754 --------------------------------
  1755 
  1756 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1757 
  1758 * changed lexical syntax of terms / types: dots made part of long
  1759 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1760 
  1761 * simpset (and claset) reference variable replaced by functions
  1762 simpset / simpset_ref;
  1763 
  1764 * no longer supports theory aliases (via merge) and non-trivial
  1765 implicit merge of thms' signatures;
  1766 
  1767 * most internal names of constants changed due to qualified names;
  1768 
  1769 * changed Pure/Sequence interface (see Pure/seq.ML);
  1770 
  1771 
  1772 *** General Changes ***
  1773 
  1774 * hierachically structured name spaces (for consts, types, axms, thms
  1775 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1776 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1777 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1778 long_names for fully qualified output names; NOTE: ML programs
  1779 (special tactics, packages etc.) referring to internal names may have
  1780 to be adapted to cope with fully qualified names; in case of severe
  1781 backward campatibility problems try setting 'global_names' at compile
  1782 time to have enrything declared within a flat name space; one may also
  1783 fine tune name declarations in theories via the 'global' and 'local'
  1784 section;
  1785 
  1786 * reimplemented the implicit simpset and claset using the new anytype
  1787 data filed in signatures; references simpset:simpset ref etc. are
  1788 replaced by functions simpset:unit->simpset and
  1789 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1790 to patch your ML files accordingly;
  1791 
  1792 * HTML output now includes theory graph data for display with Java
  1793 applet or isatool browser; data generated automatically via isatool
  1794 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1795 
  1796 * defs may now be conditional; improved rewrite_goals_tac to handle
  1797 conditional equations;
  1798 
  1799 * defs now admits additional type arguments, using TYPE('a) syntax;
  1800 
  1801 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1802 creates a new theory node; implicit merge of thms' signatures is
  1803 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1804 transfer:theory->thm->thm in (rare) cases;
  1805 
  1806 * improved handling of draft signatures / theories; draft thms (and
  1807 ctyps, cterms) are automatically promoted to real ones;
  1808 
  1809 * slightly changed interfaces for oracles: admit many per theory, named
  1810 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1811 
  1812 * print_goals: optional output of const types (set show_consts and
  1813 show_types);
  1814 
  1815 * improved output of warnings (###) and errors (***);
  1816 
  1817 * subgoal_tac displays a warning if the new subgoal has type variables;
  1818 
  1819 * removed old README and Makefiles;
  1820 
  1821 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1822 
  1823 * removed obsolete init_pps and init_database;
  1824 
  1825 * deleted the obsolete tactical STATE, which was declared by
  1826     fun STATE tacfun st = tacfun st st;
  1827 
  1828 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1829 (which abbreviates $HOME);
  1830 
  1831 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1832 use isatool fixseq to adapt your ML programs (this works for fully
  1833 qualified references to the Sequence structure only!);
  1834 
  1835 * use_thy no longer requires writable current directory; it always
  1836 reloads .ML *and* .thy file, if either one is out of date;
  1837 
  1838 
  1839 *** Classical Reasoner ***
  1840 
  1841 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1842 tactics that use classical reasoning to simplify a subgoal without
  1843 splitting it into several subgoals;
  1844 
  1845 * Safe_tac: like safe_tac but uses the default claset;
  1846 
  1847 
  1848 *** Simplifier ***
  1849 
  1850 * added simplification meta rules:
  1851     (asm_)(full_)simplify: simpset -> thm -> thm;
  1852 
  1853 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1854 logics (again);
  1855 
  1856 * added prems argument to simplification procedures;
  1857 
  1858 * HOL, FOL, ZF: added infix function `addsplits':
  1859   instead of `<simpset> setloop (split_tac <thms>)'
  1860   you can simply write `<simpset> addsplits <thms>'
  1861 
  1862 
  1863 *** Syntax ***
  1864 
  1865 * TYPE('a) syntax for type reflection terms;
  1866 
  1867 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1868 
  1869 * pretty printer: changed order of mixfix annotation preference (again!);
  1870 
  1871 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1872 
  1873 
  1874 *** HOL ***
  1875 
  1876 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1877   with `addloop' of the simplifier to faciliate case splitting in premises.
  1878 
  1879 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1880 
  1881 * HOL/Auth: new protocol proofs including some for the Internet
  1882   protocol TLS;
  1883 
  1884 * HOL/Map: new theory of `maps' a la VDM;
  1885 
  1886 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1887 cancelling out common nat summands from =, <, <= (in)equalities, or
  1888 differences; simplification procedures nat_cancel_factor for
  1889 cancelling common factor from =, <, <= (in)equalities over natural
  1890 sums; nat_cancel contains both kinds of procedures, it is installed by
  1891 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1892 
  1893 * HOL/simplifier: terms of the form
  1894   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1895   are rewritten to
  1896   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1897   and those of the form
  1898   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1899   are rewritten to
  1900   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1901 
  1902 * HOL/datatype
  1903   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1904 
  1905   P(t_case f1 ... fn x) =
  1906      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1907         ...
  1908        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1909      )
  1910 
  1911   and a theorem `split_t_case_asm' of the form
  1912 
  1913   P(t_case f1 ... fn x) =
  1914     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1915         ...
  1916        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1917      )
  1918   which can be added to a simpset via `addsplits'. The existing theorems
  1919   expand_list_case and expand_option_case have been renamed to
  1920   split_list_case and split_option_case.
  1921 
  1922 * HOL/Arithmetic:
  1923   - `pred n' is automatically converted to `n-1'.
  1924     Users are strongly encouraged not to use `pred' any longer,
  1925     because it will disappear altogether at some point.
  1926   - Users are strongly encouraged to write "0 < n" rather than
  1927     "n ~= 0". Theorems and proof tools have been modified towards this
  1928     `standard'.
  1929 
  1930 * HOL/Lists:
  1931   the function "set_of_list" has been renamed "set" (and its theorems too);
  1932   the function "nth" now takes its arguments in the reverse order and
  1933   has acquired the infix notation "!" as in "xs!n".
  1934 
  1935 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1936 
  1937 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1938   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1939 
  1940 * HOL/record: extensible records with schematic structural subtyping
  1941 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1942 still lacks various theorems and concrete record syntax;
  1943 
  1944 
  1945 *** HOLCF ***
  1946 
  1947 * removed "axioms" and "generated by" sections;
  1948 
  1949 * replaced "ops" section by extended "consts" section, which is capable of
  1950   handling the continuous function space "->" directly;
  1951 
  1952 * domain package:
  1953   . proves theorems immediately and stores them in the theory,
  1954   . creates hierachical name space,
  1955   . now uses normal mixfix annotations (instead of cinfix...),
  1956   . minor changes to some names and values (for consistency),
  1957   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1958   . separator between mutual domain defs: changed "," to "and",
  1959   . improved handling of sort constraints;  now they have to
  1960     appear on the left-hand side of the equations only;
  1961 
  1962 * fixed LAM <x,y,zs>.b syntax;
  1963 
  1964 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1965 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1966 
  1967 
  1968 *** FOL and ZF ***
  1969 
  1970 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1971   with `addloop' of the simplifier to faciliate case splitting in premises.
  1972 
  1973 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1974 in HOL, they strip ALL and --> from proved theorems;
  1975 
  1976 
  1977 
  1978 New in Isabelle94-8 (May 1997)
  1979 ------------------------------
  1980 
  1981 *** General Changes ***
  1982 
  1983 * new utilities to build / run / maintain Isabelle etc. (in parts
  1984 still somewhat experimental); old Makefiles etc. still functional;
  1985 
  1986 * new 'Isabelle System Manual';
  1987 
  1988 * INSTALL text, together with ./configure and ./build scripts;
  1989 
  1990 * reimplemented type inference for greater efficiency, better error
  1991 messages and clean internal interface;
  1992 
  1993 * prlim command for dealing with lots of subgoals (an easier way of
  1994 setting goals_limit);
  1995 
  1996 
  1997 *** Syntax ***
  1998 
  1999 * supports alternative (named) syntax tables (parser and pretty
  2000 printer); internal interface is provided by add_modesyntax(_i);
  2001 
  2002 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2003 be used in conjunction with the Isabelle symbol font; uses the
  2004 "symbols" syntax table;
  2005 
  2006 * added token_translation interface (may translate name tokens in
  2007 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2008 the current print_mode); IMPORTANT: user print translation functions
  2009 are responsible for marking newly introduced bounds
  2010 (Syntax.mark_boundT);
  2011 
  2012 * token translations for modes "xterm" and "xterm_color" that display
  2013 names in bold, underline etc. or colors (which requires a color
  2014 version of xterm);
  2015 
  2016 * infixes may now be declared with names independent of their syntax;
  2017 
  2018 * added typed_print_translation (like print_translation, but may
  2019 access type of constant);
  2020 
  2021 
  2022 *** Classical Reasoner ***
  2023 
  2024 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2025 some limitations.  Blast_tac...
  2026   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2027   + ignores elimination rules that don't have the correct format
  2028         (the conclusion MUST be a formula variable)
  2029   + ignores types, which can make HOL proofs fail
  2030   + rules must not require higher-order unification, e.g. apply_type in ZF
  2031     [message "Function Var's argument not a bound variable" relates to this]
  2032   + its proof strategy is more general but can actually be slower
  2033 
  2034 * substitution with equality assumptions no longer permutes other
  2035 assumptions;
  2036 
  2037 * minor changes in semantics of addafter (now called addaltern); renamed
  2038 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2039 (and access functions for it);
  2040 
  2041 * improved combination of classical reasoner and simplifier:
  2042   + functions for handling clasimpsets
  2043   + improvement of addss: now the simplifier is called _after_ the
  2044     safe steps.
  2045   + safe variant of addss called addSss: uses safe simplifications
  2046     _during_ the safe steps. It is more complete as it allows multiple
  2047     instantiations of unknowns (e.g. with slow_tac).
  2048 
  2049 *** Simplifier ***
  2050 
  2051 * added interface for simplification procedures (functions that
  2052 produce *proven* rewrite rules on the fly, depending on current
  2053 redex);
  2054 
  2055 * ordering on terms as parameter (used for ordered rewriting);
  2056 
  2057 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2058 
  2059 * the solver is now split into a safe and an unsafe part.
  2060 This should be invisible for the normal user, except that the
  2061 functions setsolver and addsolver have been renamed to setSolver and
  2062 addSolver; added safe_asm_full_simp_tac;
  2063 
  2064 
  2065 *** HOL ***
  2066 
  2067 * a generic induction tactic `induct_tac' which works for all datatypes and
  2068 also for type `nat';
  2069 
  2070 * a generic case distinction tactic `exhaust_tac' which works for all
  2071 datatypes and also for type `nat';
  2072 
  2073 * each datatype comes with a function `size';
  2074 
  2075 * patterns in case expressions allow tuple patterns as arguments to
  2076 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2077 
  2078 * primrec now also works with type nat;
  2079 
  2080 * recdef: a new declaration form, allows general recursive functions to be
  2081 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2082 
  2083 * the constant for negation has been renamed from "not" to "Not" to
  2084 harmonize with FOL, ZF, LK, etc.;
  2085 
  2086 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2087 infinite lists;
  2088 
  2089 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2090 
  2091 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2092 problems in commutative rings, using axiomatic type classes for + and *;
  2093 
  2094 * more examples in HOL/MiniML and HOL/Auth;
  2095 
  2096 * more default rewrite rules for quantifiers, union/intersection;
  2097 
  2098 * a new constant `arbitrary == @x.False';
  2099 
  2100 * HOLCF/IOA replaces old HOL/IOA;
  2101 
  2102 * HOLCF changes: derived all rules and arities
  2103   + axiomatic type classes instead of classes
  2104   + typedef instead of faking type definitions
  2105   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2106   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2107   + eliminated the types void, one, tr
  2108   + use unit lift and bool lift (with translations) instead of one and tr
  2109   + eliminated blift from Lift3.thy (use Def instead of blift)
  2110   all eliminated rules are derived as theorems --> no visible changes ;
  2111 
  2112 
  2113 *** ZF ***
  2114 
  2115 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2116 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2117 as ZF_cs addSIs [equalityI];
  2118 
  2119 
  2120 
  2121 New in Isabelle94-7 (November 96)
  2122 ---------------------------------
  2123 
  2124 * allowing negative levels (as offsets) in prlev and choplev;
  2125 
  2126 * super-linear speedup for large simplifications;
  2127 
  2128 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2129 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2130 FAIL); can suppress it using the command Delsimps (ex_simps @
  2131 all_simps); De Morgan laws are also now included, by default;
  2132 
  2133 * improved printing of ==>  :  ~:
  2134 
  2135 * new object-logic "Sequents" adds linear logic, while replacing LK
  2136 and Modal (thanks to Sara Kalvala);
  2137 
  2138 * HOL/Auth: correctness proofs for authentication protocols;
  2139 
  2140 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2141 examples on HOL/Auth);
  2142 
  2143 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2144 the rewriter and classical reasoner simultaneously;
  2145 
  2146 * function uresult no longer returns theorems in "standard" format;
  2147 regain previous version by: val uresult = standard o uresult;
  2148 
  2149 
  2150 
  2151 New in Isabelle94-6
  2152 -------------------
  2153 
  2154 * oracles -- these establish an interface between Isabelle and trusted
  2155 external reasoners, which may deliver results as theorems;
  2156 
  2157 * proof objects (in particular record all uses of oracles);
  2158 
  2159 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2160 
  2161 * "constdefs" section in theory files;
  2162 
  2163 * "primrec" section (HOL) no longer requires names;
  2164 
  2165 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2166 
  2167 
  2168 
  2169 New in Isabelle94-5
  2170 -------------------
  2171 
  2172 * reduced space requirements;
  2173 
  2174 * automatic HTML generation from theories;
  2175 
  2176 * theory files no longer require "..." (quotes) around most types;
  2177 
  2178 * new examples, including two proofs of the Church-Rosser theorem;
  2179 
  2180 * non-curried (1994) version of HOL is no longer distributed;
  2181 
  2182 
  2183 
  2184 New in Isabelle94-4
  2185 -------------------
  2186 
  2187 * greatly reduced space requirements;
  2188 
  2189 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2190 
  2191 * searchable theorem database (see the section "Retrieving theorems" on
  2192 page 8 of the Reference Manual);
  2193 
  2194 * new examples, including Grabczewski's monumental case study of the
  2195 Axiom of Choice;
  2196 
  2197 * The previous version of HOL renamed to Old_HOL;
  2198 
  2199 * The new version of HOL (previously called CHOL) uses a curried syntax
  2200 for functions.  Application looks like f a b instead of f(a,b);
  2201 
  2202 * Mutually recursive inductive definitions finally work in HOL;
  2203 
  2204 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2205 translates to the operator "split";
  2206 
  2207 
  2208 
  2209 New in Isabelle94-3
  2210 -------------------
  2211 
  2212 * new infix operator, addss, allowing the classical reasoner to
  2213 perform simplification at each step of its search.  Example:
  2214         fast_tac (cs addss ss)
  2215 
  2216 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2217 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2218 look like (a,b) instead of <a,b>;
  2219 
  2220 * PLEASE NOTE: CHOL will eventually replace HOL!
  2221 
  2222 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2223 It translates to the operator "split".  A new theory of integers is available;
  2224 
  2225 * In ZF, integer numerals now denote two's-complement binary integers.
  2226 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2227 
  2228 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2229 of the Axiom of Choice;
  2230 
  2231 
  2232 
  2233 New in Isabelle94-2
  2234 -------------------
  2235 
  2236 * Significantly faster resolution;
  2237 
  2238 * the different sections in a .thy file can now be mixed and repeated
  2239 freely;
  2240 
  2241 * Database of theorems for FOL, HOL and ZF.  New
  2242 commands including qed, qed_goal and bind_thm store theorems in the database.
  2243 
  2244 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2245 a given theory (thms_of), or find out what theory a theorem was proved in
  2246 (theory_of_thm);
  2247 
  2248 * Bugs fixed in the inductive definition and datatype packages;
  2249 
  2250 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2251 and HOL_dup_cs obsolete;
  2252 
  2253 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2254 have been removed;
  2255 
  2256 * Simpler definition of function space in ZF;
  2257 
  2258 * new results about cardinal and ordinal arithmetic in ZF;
  2259 
  2260 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2261 types;
  2262 
  2263 
  2264 $Id$