NEWS
author wenzelm
Wed Jul 24 00:08:52 2002 +0200 (2002-07-24)
changeset 13410 f2cd09766864
parent 13344 c8eb3fbf4c0c
child 13425 119ae829ad9b
permissions -rw-r--r--
* Pure: locale specifications now produce predicate definitions;
     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 * improved thms_containing: proper indexing of facts instead of raw
    19 theorems; check validity of results wrt. current name space; include
    20 local facts of proof configuration (also covers active locales); an
    21 optional limit for the number of printed facts may be given (the
    22 default is 40);
    23 
    24 
    25 *** HOL ***
    26 
    27 * attribute [symmetric] now works for relations as well. It turns
    28   (x,y) : R^-1 into (y,x) : R, and vice versa.
    29 
    30 * arith(_tac) does now know about div k and mod k where k is a numeral of
    31   type nat or int. It can solve simple goals like
    32   "0 < n ==> n div 2 < (n::nat)"
    33   but fails if divisibility plays a role like in
    34   "n div 2 + (n+1) div 2 = (n::nat)".
    35 * simp's arithmetic capabilities have been enhanced a bit:
    36   it now takes ~= in premises into account (by performing a case split).
    37 
    38 
    39 
    40 New in Isabelle2002 (March 2002)
    41 --------------------------------
    42 
    43 *** Document preparation ***
    44 
    45 * greatly simplified document preparation setup, including more
    46 graceful interpretation of isatool usedir -i/-d/-D options, and more
    47 instructive isatool mkdir; users should basically be able to get
    48 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    49 users may run a separate document processing stage manually like this:
    50 "isatool usedir -D output HOL Test && isatool document Test/output";
    51 
    52 * theory dependency graph may now be incorporated into documents;
    53 isatool usedir -g true will produce session_graph.eps/.pdf for use
    54 with \includegraphics of LaTeX;
    55 
    56 * proper spacing of consecutive markup elements, especially text
    57 blocks after section headings;
    58 
    59 * support bold style (for single symbols only), input syntax is like
    60 this: "\<^bold>\<alpha>" or "\<^bold>A";
    61 
    62 * \<bullet> is now output as bold \cdot by default, which looks much
    63 better in printed text;
    64 
    65 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    66 note that these symbols are currently unavailable in Proof General /
    67 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
    68 
    69 * isatool latex no longer depends on changed TEXINPUTS, instead
    70 isatool document copies the Isabelle style files to the target
    71 location;
    72 
    73 
    74 *** Isar ***
    75 
    76 * Pure/Provers: improved proof by cases and induction;
    77   - 'case' command admits impromptu naming of parameters (such as
    78     "case (Suc n)");
    79   - 'induct' method divinates rule instantiation from the inductive
    80     claim; no longer requires excessive ?P bindings for proper
    81     instantiation of cases;
    82   - 'induct' method properly enumerates all possibilities of set/type
    83     rules; as a consequence facts may be also passed through *type*
    84     rules without further ado;
    85   - 'induct' method now derives symbolic cases from the *rulified*
    86     rule (before it used to rulify cases stemming from the internal
    87     atomized version); this means that the context of a non-atomic
    88     statement becomes is included in the hypothesis, avoiding the
    89     slightly cumbersome show "PROP ?case" form;
    90   - 'induct' may now use elim-style induction rules without chaining
    91     facts, using ``missing'' premises from the goal state; this allows
    92     rules stemming from inductive sets to be applied in unstructured
    93     scripts, while still benefitting from proper handling of non-atomic
    94     statements; NB: major inductive premises need to be put first, all
    95     the rest of the goal is passed through the induction;
    96   - 'induct' proper support for mutual induction involving non-atomic
    97     rule statements (uses the new concept of simultaneous goals, see
    98     below);
    99   - append all possible rule selections, but only use the first
   100     success (no backtracking);
   101   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   102   - undeclared rule case names default to numbers 1, 2, 3, ...;
   103   - added 'print_induct_rules' (covered by help item in recent Proof
   104     General versions);
   105   - moved induct/cases attributes to Pure, methods to Provers;
   106   - generic method setup instantiated for FOL and HOL;
   107 
   108 * Pure: support multiple simultaneous goal statements, for example
   109 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   110 meta-level mechanism, this acts as if several individual goals had
   111 been stated separately; in particular common proof methods need to be
   112 repeated in order to cover all claims; note that a single elimination
   113 step is *not* sufficient to establish the two conjunctions, so this
   114 fails:
   115 
   116   assume "A & B" then have A and B ..   (*".." fails*)
   117 
   118 better use "obtain" in situations as above; alternative refer to
   119 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   120 
   121 * Pure: proper integration with ``locales''; unlike the original
   122 version by Florian Kammüller, Isar locales package high-level proof
   123 contexts rather than raw logical ones (e.g. we admit to include
   124 attributes everywhere); operations on locales include merge and
   125 rename; support for implicit arguments (``structures''); simultaneous
   126 type-inference over imports and text; see also HOL/ex/Locales.thy for
   127 some examples;
   128 
   129 * Pure: the following commands have been ``localized'', supporting a
   130 target locale specification "(in name)": 'lemma', 'theorem',
   131 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   132 stored both within the locale and at the theory level (exported and
   133 qualified by the locale name);
   134 
   135 * Pure: theory goals may now be specified in ``long'' form, with
   136 ad-hoc contexts consisting of arbitrary locale elements. for example
   137 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   138 definitions may be given, too); the result is a meta-level rule with
   139 the context elements being discharged in the obvious way;
   140 
   141 * Pure: new proof command 'using' allows to augment currently used
   142 facts after a goal statement ('using' is syntactically analogous to
   143 'apply', but acts on the goal's facts only); this allows chained facts
   144 to be separated into parts given before and after a claim, as in
   145 ``from a and b have C using d and e <proof>'';
   146 
   147 * Pure: renamed "antecedent" case to "rule_context";
   148 
   149 * Pure: new 'judgment' command records explicit information about the
   150 object-logic embedding (used by several tools internally); no longer
   151 use hard-wired "Trueprop";
   152 
   153 * Pure: added 'corollary' command;
   154 
   155 * Pure: fixed 'token_translation' command;
   156 
   157 * Pure: removed obsolete 'exported' attribute;
   158 
   159 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   160 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   161 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   162 
   163 * Pure: method 'atomize' presents local goal premises as object-level
   164 statements (atomic meta-level propositions); setup controlled via
   165 rewrite rules declarations of 'atomize' attribute; example
   166 application: 'induct' method with proper rule statements in improper
   167 proof *scripts*;
   168 
   169 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   170 now consider the syntactic context of assumptions, giving a better
   171 chance to get type-inference of the arguments right (this is
   172 especially important for locales);
   173 
   174 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   175 mode;
   176 
   177 * Pure/obtain: the formal conclusion "thesis", being marked as
   178 ``internal'', may no longer be reference directly in the text;
   179 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   180 situations;
   181 
   182 * Pure: generic 'sym' attribute which declares a rule both as pure
   183 'elim?' and for the 'symmetric' operation;
   184 
   185 * Pure: marginal comments ``--'' may now occur just anywhere in the
   186 text; the fixed correlation with particular command syntax has been
   187 discontinued;
   188 
   189 * Pure: new method 'rules' is particularly well-suited for proof
   190 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   191 but often produces more compact proof terms with less detours;
   192 
   193 * Pure/Provers/classical: simplified integration with pure rule
   194 attributes and methods; the classical "intro?/elim?/dest?"
   195 declarations coincide with the pure ones; the "rule" method no longer
   196 includes classically swapped intros; "intro" and "elim" methods no
   197 longer pick rules from the context; also got rid of ML declarations
   198 AddXIs/AddXEs/AddXDs; all of this has some potential for
   199 INCOMPATIBILITY;
   200 
   201 * Provers/classical: attribute 'swapped' produces classical inversions
   202 of introduction rules;
   203 
   204 * Provers/simplifier: 'simplified' attribute may refer to explicit
   205 rules instead of full simplifier context; 'iff' attribute handles
   206 conditional rules;
   207 
   208 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   209 
   210 * HOL: 'recdef' now fails on unfinished automated proofs, use
   211 "(permissive)" option to recover old behavior;
   212 
   213 * HOL: 'inductive' no longer features separate (collective) attributes
   214 for 'intros' (was found too confusing);
   215 
   216 * HOL: properly declared induction rules less_induct and
   217 wf_induct_rule;
   218 
   219 
   220 *** HOL ***
   221 
   222 * HOL: moved over to sane numeral syntax; the new policy is as
   223 follows:
   224 
   225   - 0 and 1 are polymorphic constants, which are defined on any
   226   numeric type (nat, int, real etc.);
   227 
   228   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   229   binary representation internally;
   230 
   231   - type nat has special constructor Suc, and generally prefers Suc 0
   232   over 1::nat and Suc (Suc 0) over 2::nat;
   233 
   234 This change may cause significant problems of INCOMPATIBILITY; here
   235 are some hints on converting existing sources:
   236 
   237   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   238   entities, so expressions involving "-" (unary or binary minus) need
   239   to be spaced properly;
   240 
   241   - existing occurrences of "1" may need to be constraint "1::nat" or
   242   even replaced by Suc 0; similar for old "2";
   243 
   244   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   245 
   246   - remove all special provisions on numerals in proofs;
   247 
   248 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   249 representation (depends on bin_arith_simps in the default context);
   250 
   251 * HOL: symbolic syntax for x^2 (numeral 2);
   252 
   253 * HOL: the class of all HOL types is now called "type" rather than
   254 "term"; INCOMPATIBILITY, need to adapt references to this type class
   255 in axclass/classes, instance/arities, and (usually rare) occurrences
   256 in typings (of consts etc.); internally the class is called
   257 "HOL.type", ML programs should refer to HOLogic.typeS;
   258 
   259 * HOL/record package improvements:
   260   - new derived operations "fields" to build a partial record section,
   261     "extend" to promote a fixed record to a record scheme, and
   262     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   263     declared as simp by default;
   264   - shared operations ("more", "fields", etc.) now need to be always
   265     qualified) --- potential INCOMPATIBILITY;
   266   - removed "make_scheme" operations (use "make" with "extend") --
   267     INCOMPATIBILITY;
   268   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   269   - provides cases/induct rules for use with corresponding Isar
   270     methods (for concrete records, record schemes, concrete more
   271     parts, and schematic more parts -- in that order);
   272   - internal definitions directly based on a light-weight abstract
   273     theory of product types over typedef rather than datatype;
   274 
   275 * HOL: generic code generator for generating executable ML code from
   276 specifications; specific support for HOL constructs such as inductive
   277 datatypes and sets, as well as recursive functions; can be invoked
   278 via 'generate_code' theory section;
   279 
   280 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   281 
   282 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   283 (beware of argument permutation!);
   284 
   285 * HOL: linorder_less_split superseded by linorder_cases;
   286 
   287 * HOL/List: "nodups" renamed to "distinct";
   288 
   289 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   290 to peripheral theory "Hilbert_Choice";
   291 
   292 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   293 in this (rare) case use:
   294 
   295   delSWrapper "split_all_tac"
   296   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   297 
   298 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   299 MAY FAIL;
   300 
   301 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   302 Isabelle's type classes, ^ on functions and relations has too general
   303 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   304 necessary to attach explicit type constraints;
   305 
   306 * HOL/Relation: the prefix name of the infix "O" has been changed from
   307 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   308 renamed accordingly (eg "compI" -> "rel_compI").
   309 
   310 * HOL: syntax translations now work properly with numerals and records
   311 expressions;
   312 
   313 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   314 of "lam" -- INCOMPATIBILITY;
   315 
   316 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   317 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   318 renamed "Product_Type.unit";
   319 
   320 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   321 
   322 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   323 the "cases" method);
   324 
   325 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   326 Florian Kammüller);
   327 
   328 * HOL/IMP: updated and converted to new-style theory format; several
   329 parts turned into readable document, with proper Isar proof texts and
   330 some explanations (by Gerwin Klein);
   331 
   332 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   333 
   334 * HOL-Hyperreal is now a logic image;
   335 
   336 
   337 *** HOLCF ***
   338 
   339 * Isar: consts/constdefs supports mixfix syntax for continuous
   340 operations;
   341 
   342 * Isar: domain package adapted to new-style theory format, e.g. see
   343 HOLCF/ex/Dnat.thy;
   344 
   345 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   346 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   347 lift.induct_tac, always use UU instead of Undef;
   348 
   349 * HOLCF/IMP: updated and converted to new-style theory;
   350 
   351 
   352 *** ZF ***
   353 
   354 * Isar: proper integration of logic-specific tools and packages,
   355 including theory commands '(co)inductive', '(co)datatype',
   356 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   357 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   358 
   359 * theory Main no longer includes AC; for the Axiom of Choice, base
   360 your theory on Main_ZFC;
   361 
   362 * the integer library now covers quotients and remainders, with many
   363 laws relating division to addition, multiplication, etc.;
   364 
   365 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   366 typeless version of the formalism;
   367 
   368 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   369 format;
   370 
   371 * ZF/Induct: new directory for examples of inductive definitions,
   372 including theory Multiset for multiset orderings; converted to
   373 new-style theory format;
   374 
   375 * ZF: many new theorems about lists, ordinals, etc.;
   376 
   377 
   378 *** General ***
   379 
   380 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   381 variable proof controls level of detail: 0 = no proofs (only oracle
   382 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   383 also ref manual for further ML interfaces;
   384 
   385 * Pure/axclass: removed obsolete ML interface
   386 goal_subclass/goal_arity;
   387 
   388 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   389 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   390 separate tokens, so expressions involving minus need to be spaced
   391 properly;
   392 
   393 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   394 rather than "infixl" or "infixr";
   395 
   396 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   397 sort constraint specifications in type inference; e.g. "x::_::foo"
   398 ensures that the type of "x" is of sort "foo" (but not necessarily a
   399 type variable);
   400 
   401 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   402 control output of nested => (types); the default behavior is
   403 "type_brackets";
   404 
   405 * Pure/syntax: builtin parse translation for "_constify" turns valued
   406 tokens into AST constants;
   407 
   408 * Pure/syntax: prefer later declarations of translations and print
   409 translation functions; potential INCOMPATIBILITY: need to reverse
   410 multiple declarations for same syntax element constant;
   411 
   412 * Pure/show_hyps reset by default (in accordance to existing Isar
   413 practice);
   414 
   415 * Provers/classical: renamed addaltern to addafter, addSaltern to
   416 addSafter;
   417 
   418 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   419 as well;
   420 
   421 * system: tested support for MacOS X; should be able to get Isabelle +
   422 Proof General to work in a plain Terminal after installing Poly/ML
   423 (e.g. from the Isabelle distribution area) and GNU bash alone
   424 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   425 support requires further installations, e.g. from
   426 http://fink.sourceforge.net/);
   427 
   428 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   429 
   430 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   431 of 40 MB), cf. ML_OPTIONS;
   432 
   433 * system: Proof General keywords specification is now part of the
   434 Isabelle distribution (see etc/isar-keywords.el);
   435 
   436 * system: support for persistent Proof General sessions (refrain from
   437 outdating all loaded theories on startup); user may create writable
   438 logic images like this: ``isabelle -q HOL Test'';
   439 
   440 * system: smart selection of Isabelle process versus Isabelle
   441 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   442 run both "isabelle" and "Isabelle" even if file names are badly
   443 damaged (executable inspects the case of the first letter of its own
   444 name); added separate "isabelle-process" and "isabelle-interface";
   445 
   446 * system: refrain from any attempt at filtering input streams; no
   447 longer support ``8bit'' encoding of old isabelle font, instead proper
   448 iso-latin characters may now be used; the related isatools
   449 "symbolinput" and "nonascii" have disappeared as well;
   450 
   451 * system: removed old "xterm" interface (the print modes "xterm" and
   452 "xterm_color" are still available for direct use in a suitable
   453 terminal);
   454 
   455 
   456 
   457 New in Isabelle99-2 (February 2001)
   458 -----------------------------------
   459 
   460 *** Overview of INCOMPATIBILITIES ***
   461 
   462 * HOL: please note that theories in the Library and elsewhere often use the
   463 new-style (Isar) format; to refer to their theorems in an ML script you must
   464 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   465 
   466 * HOL: inductive package no longer splits induction rule aggressively,
   467 but only as far as specified by the introductions given; the old
   468 format may be recovered via ML function complete_split_rule or attribute
   469 'split_rule (complete)';
   470 
   471 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   472 gfp_Tarski to gfp_unfold;
   473 
   474 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   475 
   476 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   477 relation); infix "^^" has been renamed "``"; infix "``" has been
   478 renamed "`"; "univalent" has been renamed "single_valued";
   479 
   480 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   481 operation;
   482 
   483 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   484 
   485 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   486 
   487 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   488 consequence, it is no longer monotonic wrt. the local goal context
   489 (which is now passed through the inductive cases);
   490 
   491 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   492 \<gg> to \<ggreater>;
   493 
   494 
   495 *** Document preparation ***
   496 
   497 * \isabellestyle{NAME} selects version of Isabelle output (currently
   498 available: are "it" for near math-mode best-style output, "sl" for
   499 slanted text style, and "tt" for plain type-writer; if no
   500 \isabellestyle command is given, output is according to slanted
   501 type-writer);
   502 
   503 * support sub/super scripts (for single symbols only), input syntax is
   504 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   505 
   506 * some more standard symbols; see Appendix A of the system manual for
   507 the complete list of symbols defined in isabellesym.sty;
   508 
   509 * improved isabelle style files; more abstract symbol implementation
   510 (should now use \isamath{...} and \isatext{...} in custom symbol
   511 definitions);
   512 
   513 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   514 state; Note that presentation of goal states does not conform to
   515 actual human-readable proof documents.  Please do not include goal
   516 states into document output unless you really know what you are doing!
   517 
   518 * proper indentation of antiquoted output with proportional LaTeX
   519 fonts;
   520 
   521 * no_document ML operator temporarily disables LaTeX document
   522 generation;
   523 
   524 * isatool unsymbolize tunes sources for plain ASCII communication;
   525 
   526 
   527 *** Isar ***
   528 
   529 * Pure: Isar now suffers initial goal statements to contain unbound
   530 schematic variables (this does not conform to actual readable proof
   531 documents, due to unpredictable outcome and non-compositional proof
   532 checking); users who know what they are doing may use schematic goals
   533 for Prolog-style synthesis of proven results;
   534 
   535 * Pure: assumption method (an implicit finishing) now handles actual
   536 rules as well;
   537 
   538 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   539 initial goal, declare "that" only as Pure intro (only for single
   540 steps); the "that" rule assumption may now be involved in implicit
   541 finishing, thus ".." becomes a feasible for trivial obtains;
   542 
   543 * Pure: default proof step now includes 'intro_classes'; thus trivial
   544 instance proofs may be performed by "..";
   545 
   546 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   547 statements as well;
   548 
   549 * Pure: more robust selection of calculational rules;
   550 
   551 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   552 rule (as well as the assumption rule);
   553 
   554 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   555 lemmas, using the graph browser tool;
   556 
   557 * Pure: predict failure of "show" in interactive mode;
   558 
   559 * Pure: 'thms_containing' now takes actual terms as arguments;
   560 
   561 * HOL: improved method 'induct' --- now handles non-atomic goals
   562 (potential INCOMPATIBILITY); tuned error handling;
   563 
   564 * HOL: cases and induct rules now provide explicit hints about the
   565 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   566 any remaining facts are inserted into the goal verbatim;
   567 
   568 * HOL: local contexts (aka cases) may now contain term bindings as
   569 well; the 'cases' and 'induct' methods new provide a ?case binding for
   570 the result to be shown in each case;
   571 
   572 * HOL: added 'recdef_tc' command;
   573 
   574 * isatool convert assists in eliminating legacy ML scripts;
   575 
   576 
   577 *** HOL ***
   578 
   579 * HOL/Library: a collection of generic theories to be used together
   580 with main HOL; the theory loader path already includes this directory
   581 by default; the following existing theories have been moved here:
   582 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   583 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   584 
   585 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   586 modelling and verification task performed in Isabelle/HOL +
   587 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   588 
   589 * HOL/Algebra: special summation operator SUM no longer exists, it has
   590 been replaced by setsum; infix 'assoc' now has priority 50 (like
   591 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   592 'domain', this makes the theory consistent with mathematical
   593 literature;
   594 
   595 * HOL basics: added overloaded operations "inverse" and "divide"
   596 (infix "/"), syntax for generic "abs" operation, generic summation
   597 operator \<Sum>;
   598 
   599 * HOL/typedef: simplified package, provide more useful rules (see also
   600 HOL/subset.thy);
   601 
   602 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   603 now expressed as a proper nested rule (old-style tactic scripts may
   604 require atomize_strip_tac to cope with non-atomic premises);
   605 
   606 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   607 to "split_conv" (old name still available for compatibility);
   608 
   609 * HOL: improved concrete syntax for strings (e.g. allows translation
   610 rules with string literals);
   611 
   612 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   613  and Fleuriot's mechanization of analysis, including the transcendental
   614  functions for the reals;
   615 
   616 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   617 
   618 
   619 *** CTT ***
   620 
   621 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   622 "lam" is displayed as TWO lambda-symbols
   623 
   624 * CTT: theory Main now available, containing everything (that is, Bool
   625 and Arith);
   626 
   627 
   628 *** General ***
   629 
   630 * Pure: the Simplifier has been implemented properly as a derived rule
   631 outside of the actual kernel (at last!); the overall performance
   632 penalty in practical applications is about 50%, while reliability of
   633 the Isabelle inference kernel has been greatly improved;
   634 
   635 * print modes "brackets" and "no_brackets" control output of nested =>
   636 (types) and ==> (props); the default behaviour is "brackets";
   637 
   638 * Provers: fast_tac (and friends) now handle actual object-logic rules
   639 as assumptions as well;
   640 
   641 * system: support Poly/ML 4.0;
   642 
   643 * system: isatool install handles KDE version 1 or 2;
   644 
   645 
   646 
   647 New in Isabelle99-1 (October 2000)
   648 ----------------------------------
   649 
   650 *** Overview of INCOMPATIBILITIES ***
   651 
   652 * HOL: simplification of natural numbers is much changed; to partly
   653 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   654 issue the following ML commands:
   655 
   656   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   657   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   658 
   659 * HOL: simplification no longer dives into case-expressions; this is
   660 controlled by "t.weak_case_cong" for each datatype t;
   661 
   662 * HOL: nat_less_induct renamed to less_induct;
   663 
   664 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   665 fixsome to patch .thy and .ML sources automatically;
   666 
   667   select_equality  -> some_equality
   668   select_eq_Ex     -> some_eq_ex
   669   selectI2EX       -> someI2_ex
   670   selectI2         -> someI2
   671   selectI          -> someI
   672   select1_equality -> some1_equality
   673   Eps_sym_eq       -> some_sym_eq_trivial
   674   Eps_eq           -> some_eq_trivial
   675 
   676 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   677 
   678 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   679 instead);
   680 
   681 * HOL: the recursion equations generated by 'recdef' are now called
   682 f.simps instead of f.rules;
   683 
   684 * HOL: qed_spec_mp now also handles bounded ALL as well;
   685 
   686 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   687 sometimes be needed;
   688 
   689 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   690 
   691 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   692 
   693 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   694 product is now "<*>" instead of "Times"; the lexicographic product is
   695 now "<*lex*>" instead of "**";
   696 
   697 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   698 of main HOL, but was unused); better use HOL's datatype package;
   699 
   700 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   701 the old syntax may be recovered as follows:
   702 
   703   syntax (symbols)
   704     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   705       (infixl "\\<oplus>" 100)
   706 
   707 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   708 
   709 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   710 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   711 internally;
   712 
   713 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   714 changed from A/r to A//r;
   715 
   716 * ZF: new treatment of arithmetic (nat & int) may break some old
   717 proofs;
   718 
   719 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   720 rulify -> rule_format, elimify -> elim_format, ...);
   721 
   722 * Isar/Provers: intro/elim/dest attributes changed; renamed
   723 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   724 should have to change intro!! to intro? only); replaced "delrule" by
   725 "rule del";
   726 
   727 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   728 
   729 * Provers: strengthened force_tac by using new first_best_tac;
   730 
   731 * LaTeX document preparation: several changes of isabelle.sty (see
   732 lib/texinputs);
   733 
   734 
   735 *** Document preparation ***
   736 
   737 * formal comments (text blocks etc.) in new-style theories may now
   738 contain antiquotations of thm/prop/term/typ/text to be presented
   739 according to latex print mode; concrete syntax is like this:
   740 @{term[show_types] "f(x) = a + x"};
   741 
   742 * isatool mkdir provides easy setup of Isabelle session directories,
   743 including proper document sources;
   744 
   745 * generated LaTeX sources are now deleted after successful run
   746 (isatool document -c); may retain a copy somewhere else via -D option
   747 of isatool usedir;
   748 
   749 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   750 style files, achieving self-contained LaTeX sources and simplifying
   751 LaTeX debugging;
   752 
   753 * old-style theories now produce (crude) LaTeX output as well;
   754 
   755 * browser info session directories are now self-contained (may be put
   756 on WWW server seperately); improved graphs of nested sessions; removed
   757 graph for 'all sessions';
   758 
   759 * several improvements in isabelle style files; \isabellestyle{it}
   760 produces fake math mode output; \isamarkupheader is now \section by
   761 default; see lib/texinputs/isabelle.sty etc.;
   762 
   763 
   764 *** Isar ***
   765 
   766 * Isar/Pure: local results and corresponding term bindings are now
   767 subject to Hindley-Milner polymorphism (similar to ML); this
   768 accommodates incremental type-inference very nicely;
   769 
   770 * Isar/Pure: new derived language element 'obtain' supports
   771 generalized existence reasoning;
   772 
   773 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   774 support accumulation of results, without applying any rules yet;
   775 useful to collect intermediate results without explicit name
   776 references, and for use with transitivity rules with more than 2
   777 premises;
   778 
   779 * Isar/Pure: scalable support for case-analysis type proofs: new
   780 'case' language element refers to local contexts symbolically, as
   781 produced by certain proof methods; internally, case names are attached
   782 to theorems as "tags";
   783 
   784 * Isar/Pure: theory command 'hide' removes declarations from
   785 class/type/const name spaces;
   786 
   787 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   788 indicate potential overloading;
   789 
   790 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   791 
   792 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   793 "{a,b,c}" instead of {a,b,c};
   794 
   795 * Isar/Pure now provides its own version of intro/elim/dest
   796 attributes; useful for building new logics, but beware of confusion
   797 with the version in Provers/classical;
   798 
   799 * Isar/Pure: the local context of (non-atomic) goals is provided via
   800 case name 'antecedent';
   801 
   802 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   803 to the current context is now done automatically);
   804 
   805 * Isar/Pure: theory command 'method_setup' provides a simple interface
   806 for definining proof methods in ML;
   807 
   808 * Isar/Provers: intro/elim/dest attributes changed; renamed
   809 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   810 most cases, one should have to change intro!! to intro? only);
   811 replaced "delrule" by "rule del";
   812 
   813 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   814 'symmetric' attribute (the latter supercedes [RS sym]);
   815 
   816 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   817 method modifier); 'simp' method: 'only:' modifier removes loopers as
   818 well (including splits);
   819 
   820 * Isar/Provers: Simplifier and Classical methods now support all kind
   821 of modifiers used in the past, including 'cong', 'iff', etc.
   822 
   823 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   824 of Simplifier and Classical reasoner);
   825 
   826 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   827 now support named cases; major packages (inductive, datatype, primrec,
   828 recdef) support case names and properly name parameters;
   829 
   830 * Isar/HOL: new transitivity rules for substitution in inequalities --
   831 monotonicity conditions are extracted to be proven at end of
   832 calculations;
   833 
   834 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   835 method anyway;
   836 
   837 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   838 split_if split_if_asm; datatype package provides theorems foo.splits =
   839 foo.split foo.split_asm for each datatype;
   840 
   841 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   842 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   843 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   844 use "(cases (simplified))" method in proper proof texts);
   845 
   846 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   847 
   848 * Isar: names of theorems etc. may be natural numbers as well;
   849 
   850 * Isar: 'pr' command: optional arguments for goals_limit and
   851 ProofContext.prems_limit; no longer prints theory contexts, but only
   852 proof states;
   853 
   854 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   855 additional print modes to be specified; e.g. "pr(latex)" will print
   856 proof state according to the Isabelle LaTeX style;
   857 
   858 * Isar: improved support for emulating tactic scripts, including proof
   859 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   860 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   861 (for HOL datatypes);
   862 
   863 * Isar: simplified (more robust) goal selection of proof methods: 1st
   864 goal, all goals, or explicit goal specifier (tactic emulation); thus
   865 'proof method scripts' have to be in depth-first order;
   866 
   867 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   868 
   869 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   870 should instead use individual commands for printing items
   871 (print_commands, print_methods etc.);
   872 
   873 * Isar: added 'nothing' --- the empty list of theorems;
   874 
   875 
   876 *** HOL ***
   877 
   878 * HOL/MicroJava: formalization of a fragment of Java, together with a
   879 corresponding virtual machine and a specification of its bytecode
   880 verifier and a lightweight bytecode verifier, including proofs of
   881 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   882 Cornelia Pusch (see also the homepage of project Bali at
   883 http://isabelle.in.tum.de/Bali/);
   884 
   885 * HOL/Algebra: new theory of rings and univariate polynomials, by
   886 Clemens Ballarin;
   887 
   888 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   889 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   890 Rasmussen;
   891 
   892 * HOL/Lattice: fundamental concepts of lattice theory and order
   893 structures, including duals, properties of bounds versus algebraic
   894 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   895 Theorem for complete lattices etc.; may also serve as a demonstration
   896 for abstract algebraic reasoning using axiomatic type classes, and
   897 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   898 
   899 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   900 von Oheimb;
   901 
   902 * HOL/IMPP: extension of IMP with local variables and mutually
   903 recursive procedures, by David von Oheimb;
   904 
   905 * HOL/Lambda: converted into new-style theory and document;
   906 
   907 * HOL/ex/Multiquote: example of multiple nested quotations and
   908 anti-quotations -- basically a generalized version of de-Bruijn
   909 representation; very useful in avoiding lifting of operations;
   910 
   911 * HOL/record: added general record equality rule to simpset; fixed
   912 select-update simplification procedure to handle extended records as
   913 well; admit "r" as field name;
   914 
   915 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   916 other numeric types and also as the identity of groups, rings, etc.;
   917 
   918 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   919 Types nat and int belong to this axclass;
   920 
   921 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   922    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   923    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   924   two terms #m*u and #n*u are replaced by #(m+n)*u
   925     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   926   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   927     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   928 
   929 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   930 powerful prover for predicate logic but knows nothing of clasets; see
   931 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   932 
   933 * HOL: new version of "case_tac" subsumes both boolean case split and
   934 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   935 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   936 
   937 * HOL: simplification no longer dives into case-expressions: only the
   938 selector expression is simplified, but not the remaining arms; to
   939 enable full simplification of case-expressions for datatype t, you may
   940 remove t.weak_case_cong from the simpset, either globally (Delcongs
   941 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   942 
   943 * HOL/recdef: the recursion equations generated by 'recdef' for
   944 function 'f' are now called f.simps instead of f.rules; if all
   945 termination conditions are proved automatically, these simplification
   946 rules are added to the simpset, as in primrec; rules may be named
   947 individually as well, resulting in a separate list of theorems for
   948 each equation;
   949 
   950 * HOL/While is a new theory that provides a while-combinator. It
   951 permits the definition of tail-recursive functions without the
   952 provision of a termination measure. The latter is necessary once the
   953 invariant proof rule for while is applied.
   954 
   955 * HOL: new (overloaded) notation for the set of elements below/above
   956 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   957 
   958 * HOL: theorems impI, allI, ballI bound as "strip";
   959 
   960 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   961 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   962 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   963 
   964 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   965 
   966 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   967 main HOL, but was unused);
   968 
   969 * HOL: fewer consts declared as global (e.g. have to refer to
   970 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   971 
   972 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   973 in case of overlap with user translations (e.g. judgements over
   974 tuples); (note that the underlying logical represenation is still
   975 bogus);
   976 
   977 
   978 *** ZF ***
   979 
   980 * ZF: simplification automatically cancels common terms in arithmetic
   981 expressions over nat and int;
   982 
   983 * ZF: new treatment of nat to minimize type-checking: all operators
   984 coerce their operands to a natural number using the function natify,
   985 making the algebraic laws unconditional;
   986 
   987 * ZF: as above, for int: operators coerce their operands to an integer
   988 using the function intify;
   989 
   990 * ZF: the integer library now contains many of the usual laws for the
   991 orderings, including $<=, and monotonicity laws for $+ and $*;
   992 
   993 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   994 simplification;
   995 
   996 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   997 to the simplifier and classical reasoner simultaneously;
   998 
   999 
  1000 *** General ***
  1001 
  1002 * Provers: blast_tac now handles actual object-logic rules as
  1003 assumptions; note that auto_tac uses blast_tac internally as well;
  1004 
  1005 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1006 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1007 
  1008 * Provers: delrules now handles destruct rules as well (no longer need
  1009 explicit make_elim);
  1010 
  1011 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1012   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1013 use instead the strong form,
  1014   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1015 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1016 from destruct-rules;
  1017 
  1018 * Provers: Simplifier.easy_setup provides a fast path to basic
  1019 Simplifier setup for new object-logics;
  1020 
  1021 * Pure: AST translation rules no longer require constant head on LHS;
  1022 
  1023 * Pure: improved name spaces: ambiguous output is qualified; support
  1024 for hiding of names;
  1025 
  1026 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1027 XSYMBOL_HOME; no longer need to do manual configuration in most
  1028 situations;
  1029 
  1030 * system: compression of ML heaps images may now be controlled via -c
  1031 option of isabelle and isatool usedir (currently only observed by
  1032 Poly/ML);
  1033 
  1034 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1035 useful for remote X11);
  1036 
  1037 * system: provide TAGS file for Isabelle sources;
  1038 
  1039 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1040 order;
  1041 
  1042 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1043 timing flag supersedes proof_timing and Toplevel.trace;
  1044 
  1045 * ML: new combinators |>> and |>>> for incremental transformations
  1046 with secondary results (e.g. certain theory extensions):
  1047 
  1048 * ML: PureThy.add_defs gets additional argument to indicate potential
  1049 overloading (usually false);
  1050 
  1051 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1052 results;
  1053 
  1054 
  1055 
  1056 New in Isabelle99 (October 1999)
  1057 --------------------------------
  1058 
  1059 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1060 
  1061 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1062 are no longer simplified.  (This allows the simplifier to unfold recursive
  1063 functional programs.)  To restore the old behaviour, declare
  1064 
  1065     Delcongs [if_weak_cong];
  1066 
  1067 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1068 complement;
  1069 
  1070 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1071 
  1072 * HOL/datatype: mutual_induct_tac no longer exists --
  1073   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1074 
  1075 * HOL/typedef: fixed type inference for representing set; type
  1076 arguments now have to occur explicitly on the rhs as type constraints;
  1077 
  1078 * ZF: The con_defs part of an inductive definition may no longer refer
  1079 to constants declared in the same theory;
  1080 
  1081 * HOL, ZF: the function mk_cases, generated by the inductive
  1082 definition package, has lost an argument.  To simplify its result, it
  1083 uses the default simpset instead of a supplied list of theorems.
  1084 
  1085 * HOL/List: the constructors of type list are now Nil and Cons;
  1086 
  1087 * Simplifier: the type of the infix ML functions
  1088         setSSolver addSSolver setSolver addSolver
  1089 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1090 for packaging solvers. A solver is created via
  1091         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1092 where the string argument is only a comment.
  1093 
  1094 
  1095 *** Proof tools ***
  1096 
  1097 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1098 decision procedure for linear arithmetic. Currently it is used for
  1099 types `nat', `int', and `real' in HOL (see below); it can, should and
  1100 will be instantiated for other types and logics as well.
  1101 
  1102 * The simplifier now accepts rewrite rules with flexible heads, eg
  1103      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1104   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1105   matching.
  1106 
  1107 
  1108 *** General ***
  1109 
  1110 * New Isabelle/Isar subsystem provides an alternative to traditional
  1111 tactical theorem proving; together with the ProofGeneral/isar user
  1112 interface it offers an interactive environment for developing human
  1113 readable proof documents (Isar == Intelligible semi-automated
  1114 reasoning); for further information see isatool doc isar-ref,
  1115 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1116 
  1117 * improved and simplified presentation of theories: better HTML markup
  1118 (including colors), graph views in several sizes; isatool usedir now
  1119 provides a proper interface for user theories (via -P option); actual
  1120 document preparation based on (PDF)LaTeX is available as well (for
  1121 new-style theories only); see isatool doc system for more information;
  1122 
  1123 * native support for Proof General, both for classic Isabelle and
  1124 Isabelle/Isar;
  1125 
  1126 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1127 using the graph browser tool;
  1128 
  1129 * Isabelle manuals now also available as PDF;
  1130 
  1131 * theory loader rewritten from scratch (may not be fully
  1132 bug-compatible); old loadpath variable has been replaced by show_path,
  1133 add_path, del_path, reset_path functions; new operations such as
  1134 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1135 isatool doc ref);
  1136 
  1137 * improved isatool install: option -k creates KDE application icon,
  1138 option -p DIR installs standalone binaries;
  1139 
  1140 * added ML_PLATFORM setting (useful for cross-platform installations);
  1141 more robust handling of platform specific ML images for SML/NJ;
  1142 
  1143 * the settings environment is now statically scoped, i.e. it is never
  1144 created again in sub-processes invoked from isabelle, isatool, or
  1145 Isabelle;
  1146 
  1147 * path element specification '~~' refers to '$ISABELLE_HOME';
  1148 
  1149 * in locales, the "assumes" and "defines" parts may be omitted if
  1150 empty;
  1151 
  1152 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1153 long arrows);
  1154 
  1155 * new print_mode "HTML";
  1156 
  1157 * new flag show_tags controls display of tags of theorems (which are
  1158 basically just comments that may be attached by some tools);
  1159 
  1160 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1161 mode and goal output format:
  1162 
  1163 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1164 244c244
  1165 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1166 ---
  1167 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1168 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1169 181c181
  1170 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1171 ---
  1172 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1173 
  1174 * function bind_thms stores lists of theorems (cf. bind_thm);
  1175 
  1176 * new shorthand tactics ftac, eatac, datac, fatac;
  1177 
  1178 * qed (and friends) now accept "" as result name; in that case the
  1179 theorem is not stored, but proper checks and presentation of the
  1180 result still apply;
  1181 
  1182 * theorem database now also indexes constants "Trueprop", "all",
  1183 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1184 
  1185 
  1186 *** HOL ***
  1187 
  1188 ** HOL arithmetic **
  1189 
  1190 * There are now decision procedures for linear arithmetic over nat and
  1191 int:
  1192 
  1193 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1194 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1195 are treated as atomic; subformulae not involving type `nat' or `int'
  1196 are ignored; quantified subformulae are ignored unless they are
  1197 positive universal or negative existential. The tactic has to be
  1198 invoked by hand and can be a little bit slow. In particular, the
  1199 running time is exponential in the number of occurrences of `min' and
  1200 `max', and `-' on `nat'.
  1201 
  1202 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1203 (negated) (in)equalities among the premises and the conclusion into
  1204 account (i.e. no compound formulae) and does not know about `min' and
  1205 `max', and `-' on `nat'. It is fast and is used automatically by the
  1206 simplifier.
  1207 
  1208 NB: At the moment, these decision procedures do not cope with mixed
  1209 nat/int formulae where the two parts interact, such as `m < n ==>
  1210 int(m) < int(n)'.
  1211 
  1212 * HOL/Numeral provides a generic theory of numerals (encoded
  1213 efficiently as bit strings); setup for types nat/int/real is in place;
  1214 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1215 int, existing theories and proof scripts may require a few additional
  1216 type constraints;
  1217 
  1218 * integer division and remainder can now be performed on constant
  1219 arguments;
  1220 
  1221 * many properties of integer multiplication, division and remainder
  1222 are now available;
  1223 
  1224 * An interface to the Stanford Validity Checker (SVC) is available through the
  1225 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1226 are proved automatically.  SVC must be installed separately, and its results
  1227 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1228 invocation of the underlying oracle).  For SVC see
  1229   http://verify.stanford.edu/SVC
  1230 
  1231 * IsaMakefile: the HOL-Real target now builds an actual image;
  1232 
  1233 
  1234 ** HOL misc **
  1235 
  1236 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1237 (in Isabelle/Isar) -- by Gertrud Bauer;
  1238 
  1239 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1240 analysis for assembly languages with subtypes;
  1241 
  1242 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1243 -- avoids syntactic ambiguities and treats state, transition, and
  1244 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1245 changed syntax and (many) tactics;
  1246 
  1247 * HOL/inductive: Now also handles more general introduction rules such
  1248   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1249   theorems are now maintained within the theory (maintained via the
  1250   "mono" attribute);
  1251 
  1252 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1253   (using function types) such as
  1254 
  1255   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1256 
  1257 * HOL/record: record_simproc (part of the default simpset) takes care
  1258 of selectors applied to updated records; record_split_tac is no longer
  1259 part of the default claset; update_defs may now be removed from the
  1260 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1261 
  1262   claset_ref () := claset() addSWrapper record_split_wrapper;
  1263   Delsimprocs [record_simproc]
  1264 
  1265 * HOL/typedef: fixed type inference for representing set; type
  1266 arguments now have to occur explicitly on the rhs as type constraints;
  1267 
  1268 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1269 names rather than an ML expression;
  1270 
  1271 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1272 supplied later.  Program schemes can be defined, such as
  1273     "While B C s = (if B s then While B C (C s) else s)"
  1274 where the well-founded relation can be chosen after B and C have been given.
  1275 
  1276 * HOL/List: the constructors of type list are now Nil and Cons;
  1277 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1278 course, ML tools referring to List.list.op # etc. have to be adapted;
  1279 
  1280 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1281 disabled by default; run isabelle with option -m HOL to get back to
  1282 the original Gordon/HOL-style output;
  1283 
  1284 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1285 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1286 
  1287 * HOL basic syntax simplified (more orthogonal): all variants of
  1288 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1289 Eps operator is provided as well: "SOME x. P[x]";
  1290 
  1291 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1292 
  1293 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1294 thus available for user theories;
  1295 
  1296 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1297 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1298 time;
  1299 
  1300 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1301 several times and then mp;
  1302 
  1303 
  1304 *** LK ***
  1305 
  1306 * the notation <<...>> is now available as a notation for sequences of
  1307 formulas;
  1308 
  1309 * the simplifier is now installed
  1310 
  1311 * the axiom system has been generalized (thanks to Soren Heilmann)
  1312 
  1313 * the classical reasoner now has a default rule database
  1314 
  1315 
  1316 *** ZF ***
  1317 
  1318 * new primrec section allows primitive recursive functions to be given
  1319 directly (as in HOL) over datatypes and the natural numbers;
  1320 
  1321 * new tactics induct_tac and exhaust_tac for induction (or case
  1322 analysis) over datatypes and the natural numbers;
  1323 
  1324 * the datatype declaration of type T now defines the recursor T_rec;
  1325 
  1326 * simplification automatically does freeness reasoning for datatype
  1327 constructors;
  1328 
  1329 * automatic type-inference, with AddTCs command to insert new
  1330 type-checking rules;
  1331 
  1332 * datatype introduction rules are now added as Safe Introduction rules
  1333 to the claset;
  1334 
  1335 * the syntax "if P then x else y" is now available in addition to
  1336 if(P,x,y);
  1337 
  1338 
  1339 *** Internal programming interfaces ***
  1340 
  1341 * tuned simplifier trace output; new flag debug_simp;
  1342 
  1343 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1344 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1345 
  1346 * AxClass.axclass_tac lost the theory argument;
  1347 
  1348 * tuned current_goals_markers semantics: begin / end goal avoids
  1349 printing empty lines;
  1350 
  1351 * removed prs and prs_fn hook, which was broken because it did not
  1352 include \n in its semantics, forcing writeln to add one
  1353 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1354 string -> unit if you really want to output text without newline;
  1355 
  1356 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1357 plain output, interface builders may have to enable 'isabelle_font'
  1358 mode to get Isabelle font glyphs as before;
  1359 
  1360 * refined token_translation interface; INCOMPATIBILITY: output length
  1361 now of type real instead of int;
  1362 
  1363 * theory loader actions may be traced via new ThyInfo.add_hook
  1364 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1365 your own database of information attached to *whole* theories -- as
  1366 opposed to intra-theory data slots offered via TheoryDataFun;
  1367 
  1368 * proper handling of dangling sort hypotheses (at last!);
  1369 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1370 extra sort hypotheses that can be witnessed from the type signature;
  1371 the force_strip_shyps flag is gone, any remaining shyps are simply
  1372 left in the theorem (with a warning issued by strip_shyps_warning);
  1373 
  1374 
  1375 
  1376 New in Isabelle98-1 (October 1998)
  1377 ----------------------------------
  1378 
  1379 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1380 
  1381 * several changes of automated proof tools;
  1382 
  1383 * HOL: major changes to the inductive and datatype packages, including
  1384 some minor incompatibilities of theory syntax;
  1385 
  1386 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1387 called `inj_on';
  1388 
  1389 * HOL: removed duplicate thms in Arith:
  1390   less_imp_add_less  should be replaced by  trans_less_add1
  1391   le_imp_add_le      should be replaced by  trans_le_add1
  1392 
  1393 * HOL: unary minus is now overloaded (new type constraints may be
  1394 required);
  1395 
  1396 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1397 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1398 now taken as an integer constant.
  1399 
  1400 * Pure: ML function 'theory_of' renamed to 'theory';
  1401 
  1402 
  1403 *** Proof tools ***
  1404 
  1405 * Simplifier:
  1406   1. Asm_full_simp_tac is now more aggressive.
  1407      1. It will sometimes reorient premises if that increases their power to
  1408         simplify.
  1409      2. It does no longer proceed strictly from left to right but may also
  1410         rotate premises to achieve further simplification.
  1411      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1412      old Asm_full_simp_tac in that it does not rotate premises.
  1413   2. The simplifier now knows a little bit about nat-arithmetic.
  1414 
  1415 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1416 allows for selected deletion of wrappers, by introduction of names for
  1417 wrapper functionals.  This implies that addbefore, addSbefore,
  1418 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1419 and that adding two tactics with the same name overwrites the first
  1420 one (emitting a warning).
  1421   type wrapper = (int -> tactic) -> (int -> tactic)
  1422   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1423   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1424   delWrapper, delSWrapper: claset *  string            -> claset
  1425   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1426 
  1427 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1428 semantics; addbefore now affects only the unsafe part of step_tac
  1429 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1430 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1431 by Force_tac;
  1432 
  1433 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1434 compWrapper; added safe wrapper (and access functions for it);
  1435 
  1436 * HOL/split_all_tac is now much faster and fails if there is nothing
  1437 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1438 and the names of the automatically generated variables have changed.
  1439 split_all_tac has moved within claset() from unsafe wrappers to safe
  1440 wrappers, which means that !!-bound variables are split much more
  1441 aggressively, and safe_tac and clarify_tac now split such variables.
  1442 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1443 Note: the same holds for record_split_tac, which does the job of
  1444 split_all_tac for record fields.
  1445 
  1446 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1447 permanently to the default simpset using Addsplits just like
  1448 Addsimps. They can be removed via Delsplits just like
  1449 Delsimps. Lower-case versions are also available.
  1450 
  1451 * HOL/Simplifier: The rule split_if is now part of the default
  1452 simpset. This means that the simplifier will eliminate all occurrences
  1453 of if-then-else in the conclusion of a goal. To prevent this, you can
  1454 either remove split_if completely from the default simpset by
  1455 `Delsplits [split_if]' or remove it in a specific call of the
  1456 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1457 other case splitting rules to/from the default simpset: every datatype
  1458 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1459 t is the name of the datatype).
  1460 
  1461 * Classical reasoner / Simplifier combination: new force_tac (and
  1462 derivatives Force_tac, force) combines rewriting and classical
  1463 reasoning (and whatever other tools) similarly to auto_tac, but is
  1464 aimed to solve the given subgoal completely.
  1465 
  1466 
  1467 *** General ***
  1468 
  1469 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1470 and `goalw': the theory is no longer needed as an explicit argument -
  1471 the current theory context is used; assumptions are no longer returned
  1472 at the ML-level unless one of them starts with ==> or !!; it is
  1473 recommended to convert to these new commands using isatool fixgoal
  1474 (backup your sources first!);
  1475 
  1476 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1477 the current theory context, and 'theory' to lookup stored theories;
  1478 
  1479 * new theory section 'locale' for declaring constants, assumptions and
  1480 definitions that have local scope;
  1481 
  1482 * new theory section 'nonterminals' for purely syntactic types;
  1483 
  1484 * new theory section 'setup' for generic ML setup functions
  1485 (e.g. package initialization);
  1486 
  1487 * the distribution now includes Isabelle icons: see
  1488 lib/logo/isabelle-{small,tiny}.xpm;
  1489 
  1490 * isatool install - install binaries with absolute references to
  1491 ISABELLE_HOME/bin;
  1492 
  1493 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1494 
  1495 * print mode 'emacs' reserved for Isamode;
  1496 
  1497 * support multiple print (ast) translations per constant name;
  1498 
  1499 * theorems involving oracles are now printed with a suffixed [!];
  1500 
  1501 
  1502 *** HOL ***
  1503 
  1504 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1505 
  1506 * HOL/inductive package reorganized and improved: now supports mutual
  1507 definitions such as
  1508 
  1509   inductive EVEN ODD
  1510     intrs
  1511       null "0 : EVEN"
  1512       oddI "n : EVEN ==> Suc n : ODD"
  1513       evenI "n : ODD ==> Suc n : EVEN"
  1514 
  1515 new theorem list "elims" contains an elimination rule for each of the
  1516 recursive sets; inductive definitions now handle disjunctive premises
  1517 correctly (also ZF);
  1518 
  1519 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1520 "mutual_induct" no longer exists - the induction rule is always
  1521 contained in "induct";
  1522 
  1523 
  1524 * HOL/datatype package re-implemented and greatly improved: now
  1525 supports mutually recursive datatypes such as
  1526 
  1527   datatype
  1528     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1529             | SUM ('a aexp) ('a aexp)
  1530             | DIFF ('a aexp) ('a aexp)
  1531             | NUM 'a
  1532   and
  1533     'a bexp = LESS ('a aexp) ('a aexp)
  1534             | AND ('a bexp) ('a bexp)
  1535             | OR ('a bexp) ('a bexp)
  1536 
  1537 as well as indirectly recursive datatypes such as
  1538 
  1539   datatype
  1540     ('a, 'b) term = Var 'a
  1541                   | App 'b ((('a, 'b) term) list)
  1542 
  1543 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1544 induction on mutually / indirectly recursive datatypes.
  1545 
  1546 Primrec equations are now stored in theory and can be accessed via
  1547 <function_name>.simps.
  1548 
  1549 INCOMPATIBILITIES:
  1550 
  1551   - Theories using datatypes must now have theory Datatype as an
  1552     ancestor.
  1553   - The specific <typename>.induct_tac no longer exists - use the
  1554     generic induct_tac instead.
  1555   - natE has been renamed to nat.exhaust - use exhaust_tac
  1556     instead of res_inst_tac ... natE. Note that the variable
  1557     names in nat.exhaust differ from the names in natE, this
  1558     may cause some "fragile" proofs to fail.
  1559   - The theorems split_<typename>_case and split_<typename>_case_asm
  1560     have been renamed to <typename>.split and <typename>.split_asm.
  1561   - Since default sorts of type variables are now handled correctly,
  1562     some datatype definitions may have to be annotated with explicit
  1563     sort constraints.
  1564   - Primrec definitions no longer require function name and type
  1565     of recursive argument.
  1566 
  1567 Consider using isatool fixdatatype to adapt your theories and proof
  1568 scripts to the new package (backup your sources first!).
  1569 
  1570 
  1571 * HOL/record package: considerably improved implementation; now
  1572 includes concrete syntax for record types, terms, updates; theorems
  1573 for surjective pairing and splitting !!-bound record variables; proof
  1574 support is as follows:
  1575 
  1576   1) standard conversions (selectors or updates applied to record
  1577 constructor terms) are part of the standard simpset;
  1578 
  1579   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1580 made part of standard simpset and claset via addIffs;
  1581 
  1582   3) a tactic for record field splitting (record_split_tac) is part of
  1583 the standard claset (addSWrapper);
  1584 
  1585 To get a better idea about these rules you may retrieve them via
  1586 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1587 the name of your record type.
  1588 
  1589 The split tactic 3) conceptually simplifies by the following rule:
  1590 
  1591   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1592 
  1593 Thus any record variable that is bound by meta-all will automatically
  1594 blow up into some record constructor term, consequently the
  1595 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1596 solve record problems automatically.
  1597 
  1598 
  1599 * reorganized the main HOL image: HOL/Integ and String loaded by
  1600 default; theory Main includes everything;
  1601 
  1602 * automatic simplification of integer sums and comparisons, using cancellation;
  1603 
  1604 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1605 
  1606 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1607 
  1608 * many new identities for unions, intersections, set difference, etc.;
  1609 
  1610 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1611 called split_if, split_split, split_sum_case and split_nat_case (to go
  1612 with add/delsplits);
  1613 
  1614 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1615 (?x::unit) = (); this is made part of the default simpset, which COULD
  1616 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1617 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1618 unit_abs_eta_conv is added in order to counter the effect of
  1619 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1620 %u.f();
  1621 
  1622 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1623 makes more sense);
  1624 
  1625 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1626   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1627   disjointness reasoning but breaking a few old proofs.
  1628 
  1629 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1630 to 'converse' from 'inverse' (for compatibility with ZF and some
  1631 literature);
  1632 
  1633 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1634 the well-founded relation;
  1635 
  1636 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1637     Compl A.  The "Compl" syntax remains available as input syntax for this
  1638     release ONLY.
  1639 
  1640 * HOL/Update: new theory of function updates:
  1641     f(a:=b) == %x. if x=a then b else f x
  1642 may also be iterated as in f(a:=b,c:=d,...);
  1643 
  1644 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1645 
  1646 * HOL/List:
  1647   - new function list_update written xs[i:=v] that updates the i-th
  1648     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1649   - new function `upt' written [i..j(] which generates the list
  1650     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1651     bound write [i..j], which is a shorthand for [i..j+1(].
  1652   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1653 
  1654 * HOL/Arith:
  1655   - removed 'pred' (predecessor) function;
  1656   - generalized some theorems about n-1;
  1657   - many new laws about "div" and "mod";
  1658   - new laws about greatest common divisors (see theory ex/Primes);
  1659 
  1660 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1661 instead of "inverse";
  1662 
  1663 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1664   of the multiset ordering;
  1665 
  1666 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1667   (not included by default);
  1668 
  1669 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1670 
  1671 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1672   programs, i.e. different program variables may have different types.
  1673 
  1674 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1675   [previously, this check worked only if the rewrite rule was unconditional]
  1676   Now rew can involve either definitions or equalities (either == or =).
  1677 
  1678 
  1679 *** ZF ***
  1680 
  1681 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1682   only the theorems proved on ZF.ML;
  1683 
  1684 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1685   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1686   disjointness reasoning but breaking a few old proofs.
  1687 
  1688 * ZF/Update: new theory of function updates
  1689     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1690   may also be iterated as in f(a:=b,c:=d,...);
  1691 
  1692 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1693 
  1694 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1695   [previously, this check worked only if the rewrite rule was unconditional]
  1696   Now rew can involve either definitions or equalities (either == or =).
  1697 
  1698 * case_tac provided for compatibility with HOL
  1699     (like the old excluded_middle_tac, but with subgoals swapped)
  1700 
  1701 
  1702 *** Internal programming interfaces ***
  1703 
  1704 * Pure: several new basic modules made available for general use, see
  1705 also src/Pure/README;
  1706 
  1707 * improved the theory data mechanism to support encapsulation (data
  1708 kind name replaced by private Object.kind, acting as authorization
  1709 key); new type-safe user interface via functor TheoryDataFun; generic
  1710 print_data function becomes basically useless;
  1711 
  1712 * removed global_names compatibility flag -- all theory declarations
  1713 are qualified by default;
  1714 
  1715 * module Pure/Syntax now offers quote / antiquote translation
  1716 functions (useful for Hoare logic etc. with implicit dependencies);
  1717 see HOL/ex/Antiquote for an example use;
  1718 
  1719 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1720 cterm -> thm;
  1721 
  1722 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1723 subgoal;
  1724 
  1725 * Display.print_goals function moved to Locale.print_goals;
  1726 
  1727 * standard print function for goals supports current_goals_markers
  1728 variable for marking begin of proof, end of proof, start of goal; the
  1729 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1730 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1731 for example;
  1732 
  1733 
  1734 
  1735 New in Isabelle98 (January 1998)
  1736 --------------------------------
  1737 
  1738 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1739 
  1740 * changed lexical syntax of terms / types: dots made part of long
  1741 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1742 
  1743 * simpset (and claset) reference variable replaced by functions
  1744 simpset / simpset_ref;
  1745 
  1746 * no longer supports theory aliases (via merge) and non-trivial
  1747 implicit merge of thms' signatures;
  1748 
  1749 * most internal names of constants changed due to qualified names;
  1750 
  1751 * changed Pure/Sequence interface (see Pure/seq.ML);
  1752 
  1753 
  1754 *** General Changes ***
  1755 
  1756 * hierachically structured name spaces (for consts, types, axms, thms
  1757 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1758 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1759 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1760 long_names for fully qualified output names; NOTE: ML programs
  1761 (special tactics, packages etc.) referring to internal names may have
  1762 to be adapted to cope with fully qualified names; in case of severe
  1763 backward campatibility problems try setting 'global_names' at compile
  1764 time to have enrything declared within a flat name space; one may also
  1765 fine tune name declarations in theories via the 'global' and 'local'
  1766 section;
  1767 
  1768 * reimplemented the implicit simpset and claset using the new anytype
  1769 data filed in signatures; references simpset:simpset ref etc. are
  1770 replaced by functions simpset:unit->simpset and
  1771 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1772 to patch your ML files accordingly;
  1773 
  1774 * HTML output now includes theory graph data for display with Java
  1775 applet or isatool browser; data generated automatically via isatool
  1776 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1777 
  1778 * defs may now be conditional; improved rewrite_goals_tac to handle
  1779 conditional equations;
  1780 
  1781 * defs now admits additional type arguments, using TYPE('a) syntax;
  1782 
  1783 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1784 creates a new theory node; implicit merge of thms' signatures is
  1785 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1786 transfer:theory->thm->thm in (rare) cases;
  1787 
  1788 * improved handling of draft signatures / theories; draft thms (and
  1789 ctyps, cterms) are automatically promoted to real ones;
  1790 
  1791 * slightly changed interfaces for oracles: admit many per theory, named
  1792 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1793 
  1794 * print_goals: optional output of const types (set show_consts and
  1795 show_types);
  1796 
  1797 * improved output of warnings (###) and errors (***);
  1798 
  1799 * subgoal_tac displays a warning if the new subgoal has type variables;
  1800 
  1801 * removed old README and Makefiles;
  1802 
  1803 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1804 
  1805 * removed obsolete init_pps and init_database;
  1806 
  1807 * deleted the obsolete tactical STATE, which was declared by
  1808     fun STATE tacfun st = tacfun st st;
  1809 
  1810 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1811 (which abbreviates $HOME);
  1812 
  1813 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1814 use isatool fixseq to adapt your ML programs (this works for fully
  1815 qualified references to the Sequence structure only!);
  1816 
  1817 * use_thy no longer requires writable current directory; it always
  1818 reloads .ML *and* .thy file, if either one is out of date;
  1819 
  1820 
  1821 *** Classical Reasoner ***
  1822 
  1823 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1824 tactics that use classical reasoning to simplify a subgoal without
  1825 splitting it into several subgoals;
  1826 
  1827 * Safe_tac: like safe_tac but uses the default claset;
  1828 
  1829 
  1830 *** Simplifier ***
  1831 
  1832 * added simplification meta rules:
  1833     (asm_)(full_)simplify: simpset -> thm -> thm;
  1834 
  1835 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1836 logics (again);
  1837 
  1838 * added prems argument to simplification procedures;
  1839 
  1840 * HOL, FOL, ZF: added infix function `addsplits':
  1841   instead of `<simpset> setloop (split_tac <thms>)'
  1842   you can simply write `<simpset> addsplits <thms>'
  1843 
  1844 
  1845 *** Syntax ***
  1846 
  1847 * TYPE('a) syntax for type reflection terms;
  1848 
  1849 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1850 
  1851 * pretty printer: changed order of mixfix annotation preference (again!);
  1852 
  1853 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1854 
  1855 
  1856 *** HOL ***
  1857 
  1858 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1859   with `addloop' of the simplifier to faciliate case splitting in premises.
  1860 
  1861 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1862 
  1863 * HOL/Auth: new protocol proofs including some for the Internet
  1864   protocol TLS;
  1865 
  1866 * HOL/Map: new theory of `maps' a la VDM;
  1867 
  1868 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1869 cancelling out common nat summands from =, <, <= (in)equalities, or
  1870 differences; simplification procedures nat_cancel_factor for
  1871 cancelling common factor from =, <, <= (in)equalities over natural
  1872 sums; nat_cancel contains both kinds of procedures, it is installed by
  1873 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1874 
  1875 * HOL/simplifier: terms of the form
  1876   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1877   are rewritten to
  1878   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1879   and those of the form
  1880   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1881   are rewritten to
  1882   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1883 
  1884 * HOL/datatype
  1885   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1886 
  1887   P(t_case f1 ... fn x) =
  1888      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1889         ...
  1890        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1891      )
  1892 
  1893   and a theorem `split_t_case_asm' of the form
  1894 
  1895   P(t_case f1 ... fn x) =
  1896     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1897         ...
  1898        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1899      )
  1900   which can be added to a simpset via `addsplits'. The existing theorems
  1901   expand_list_case and expand_option_case have been renamed to
  1902   split_list_case and split_option_case.
  1903 
  1904 * HOL/Arithmetic:
  1905   - `pred n' is automatically converted to `n-1'.
  1906     Users are strongly encouraged not to use `pred' any longer,
  1907     because it will disappear altogether at some point.
  1908   - Users are strongly encouraged to write "0 < n" rather than
  1909     "n ~= 0". Theorems and proof tools have been modified towards this
  1910     `standard'.
  1911 
  1912 * HOL/Lists:
  1913   the function "set_of_list" has been renamed "set" (and its theorems too);
  1914   the function "nth" now takes its arguments in the reverse order and
  1915   has acquired the infix notation "!" as in "xs!n".
  1916 
  1917 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1918 
  1919 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1920   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1921 
  1922 * HOL/record: extensible records with schematic structural subtyping
  1923 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1924 still lacks various theorems and concrete record syntax;
  1925 
  1926 
  1927 *** HOLCF ***
  1928 
  1929 * removed "axioms" and "generated by" sections;
  1930 
  1931 * replaced "ops" section by extended "consts" section, which is capable of
  1932   handling the continuous function space "->" directly;
  1933 
  1934 * domain package:
  1935   . proves theorems immediately and stores them in the theory,
  1936   . creates hierachical name space,
  1937   . now uses normal mixfix annotations (instead of cinfix...),
  1938   . minor changes to some names and values (for consistency),
  1939   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1940   . separator between mutual domain defs: changed "," to "and",
  1941   . improved handling of sort constraints;  now they have to
  1942     appear on the left-hand side of the equations only;
  1943 
  1944 * fixed LAM <x,y,zs>.b syntax;
  1945 
  1946 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1947 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1948 
  1949 
  1950 *** FOL and ZF ***
  1951 
  1952 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1953   with `addloop' of the simplifier to faciliate case splitting in premises.
  1954 
  1955 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1956 in HOL, they strip ALL and --> from proved theorems;
  1957 
  1958 
  1959 
  1960 New in Isabelle94-8 (May 1997)
  1961 ------------------------------
  1962 
  1963 *** General Changes ***
  1964 
  1965 * new utilities to build / run / maintain Isabelle etc. (in parts
  1966 still somewhat experimental); old Makefiles etc. still functional;
  1967 
  1968 * new 'Isabelle System Manual';
  1969 
  1970 * INSTALL text, together with ./configure and ./build scripts;
  1971 
  1972 * reimplemented type inference for greater efficiency, better error
  1973 messages and clean internal interface;
  1974 
  1975 * prlim command for dealing with lots of subgoals (an easier way of
  1976 setting goals_limit);
  1977 
  1978 
  1979 *** Syntax ***
  1980 
  1981 * supports alternative (named) syntax tables (parser and pretty
  1982 printer); internal interface is provided by add_modesyntax(_i);
  1983 
  1984 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1985 be used in conjunction with the Isabelle symbol font; uses the
  1986 "symbols" syntax table;
  1987 
  1988 * added token_translation interface (may translate name tokens in
  1989 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1990 the current print_mode); IMPORTANT: user print translation functions
  1991 are responsible for marking newly introduced bounds
  1992 (Syntax.mark_boundT);
  1993 
  1994 * token translations for modes "xterm" and "xterm_color" that display
  1995 names in bold, underline etc. or colors (which requires a color
  1996 version of xterm);
  1997 
  1998 * infixes may now be declared with names independent of their syntax;
  1999 
  2000 * added typed_print_translation (like print_translation, but may
  2001 access type of constant);
  2002 
  2003 
  2004 *** Classical Reasoner ***
  2005 
  2006 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2007 some limitations.  Blast_tac...
  2008   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2009   + ignores elimination rules that don't have the correct format
  2010         (the conclusion MUST be a formula variable)
  2011   + ignores types, which can make HOL proofs fail
  2012   + rules must not require higher-order unification, e.g. apply_type in ZF
  2013     [message "Function Var's argument not a bound variable" relates to this]
  2014   + its proof strategy is more general but can actually be slower
  2015 
  2016 * substitution with equality assumptions no longer permutes other
  2017 assumptions;
  2018 
  2019 * minor changes in semantics of addafter (now called addaltern); renamed
  2020 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2021 (and access functions for it);
  2022 
  2023 * improved combination of classical reasoner and simplifier:
  2024   + functions for handling clasimpsets
  2025   + improvement of addss: now the simplifier is called _after_ the
  2026     safe steps.
  2027   + safe variant of addss called addSss: uses safe simplifications
  2028     _during_ the safe steps. It is more complete as it allows multiple
  2029     instantiations of unknowns (e.g. with slow_tac).
  2030 
  2031 *** Simplifier ***
  2032 
  2033 * added interface for simplification procedures (functions that
  2034 produce *proven* rewrite rules on the fly, depending on current
  2035 redex);
  2036 
  2037 * ordering on terms as parameter (used for ordered rewriting);
  2038 
  2039 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2040 
  2041 * the solver is now split into a safe and an unsafe part.
  2042 This should be invisible for the normal user, except that the
  2043 functions setsolver and addsolver have been renamed to setSolver and
  2044 addSolver; added safe_asm_full_simp_tac;
  2045 
  2046 
  2047 *** HOL ***
  2048 
  2049 * a generic induction tactic `induct_tac' which works for all datatypes and
  2050 also for type `nat';
  2051 
  2052 * a generic case distinction tactic `exhaust_tac' which works for all
  2053 datatypes and also for type `nat';
  2054 
  2055 * each datatype comes with a function `size';
  2056 
  2057 * patterns in case expressions allow tuple patterns as arguments to
  2058 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2059 
  2060 * primrec now also works with type nat;
  2061 
  2062 * recdef: a new declaration form, allows general recursive functions to be
  2063 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2064 
  2065 * the constant for negation has been renamed from "not" to "Not" to
  2066 harmonize with FOL, ZF, LK, etc.;
  2067 
  2068 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2069 infinite lists;
  2070 
  2071 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2072 
  2073 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2074 problems in commutative rings, using axiomatic type classes for + and *;
  2075 
  2076 * more examples in HOL/MiniML and HOL/Auth;
  2077 
  2078 * more default rewrite rules for quantifiers, union/intersection;
  2079 
  2080 * a new constant `arbitrary == @x.False';
  2081 
  2082 * HOLCF/IOA replaces old HOL/IOA;
  2083 
  2084 * HOLCF changes: derived all rules and arities
  2085   + axiomatic type classes instead of classes
  2086   + typedef instead of faking type definitions
  2087   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2088   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2089   + eliminated the types void, one, tr
  2090   + use unit lift and bool lift (with translations) instead of one and tr
  2091   + eliminated blift from Lift3.thy (use Def instead of blift)
  2092   all eliminated rules are derived as theorems --> no visible changes ;
  2093 
  2094 
  2095 *** ZF ***
  2096 
  2097 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2098 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2099 as ZF_cs addSIs [equalityI];
  2100 
  2101 
  2102 
  2103 New in Isabelle94-7 (November 96)
  2104 ---------------------------------
  2105 
  2106 * allowing negative levels (as offsets) in prlev and choplev;
  2107 
  2108 * super-linear speedup for large simplifications;
  2109 
  2110 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2111 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2112 FAIL); can suppress it using the command Delsimps (ex_simps @
  2113 all_simps); De Morgan laws are also now included, by default;
  2114 
  2115 * improved printing of ==>  :  ~:
  2116 
  2117 * new object-logic "Sequents" adds linear logic, while replacing LK
  2118 and Modal (thanks to Sara Kalvala);
  2119 
  2120 * HOL/Auth: correctness proofs for authentication protocols;
  2121 
  2122 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2123 examples on HOL/Auth);
  2124 
  2125 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2126 the rewriter and classical reasoner simultaneously;
  2127 
  2128 * function uresult no longer returns theorems in "standard" format;
  2129 regain previous version by: val uresult = standard o uresult;
  2130 
  2131 
  2132 
  2133 New in Isabelle94-6
  2134 -------------------
  2135 
  2136 * oracles -- these establish an interface between Isabelle and trusted
  2137 external reasoners, which may deliver results as theorems;
  2138 
  2139 * proof objects (in particular record all uses of oracles);
  2140 
  2141 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2142 
  2143 * "constdefs" section in theory files;
  2144 
  2145 * "primrec" section (HOL) no longer requires names;
  2146 
  2147 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2148 
  2149 
  2150 
  2151 New in Isabelle94-5
  2152 -------------------
  2153 
  2154 * reduced space requirements;
  2155 
  2156 * automatic HTML generation from theories;
  2157 
  2158 * theory files no longer require "..." (quotes) around most types;
  2159 
  2160 * new examples, including two proofs of the Church-Rosser theorem;
  2161 
  2162 * non-curried (1994) version of HOL is no longer distributed;
  2163 
  2164 
  2165 
  2166 New in Isabelle94-4
  2167 -------------------
  2168 
  2169 * greatly reduced space requirements;
  2170 
  2171 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2172 
  2173 * searchable theorem database (see the section "Retrieving theorems" on
  2174 page 8 of the Reference Manual);
  2175 
  2176 * new examples, including Grabczewski's monumental case study of the
  2177 Axiom of Choice;
  2178 
  2179 * The previous version of HOL renamed to Old_HOL;
  2180 
  2181 * The new version of HOL (previously called CHOL) uses a curried syntax
  2182 for functions.  Application looks like f a b instead of f(a,b);
  2183 
  2184 * Mutually recursive inductive definitions finally work in HOL;
  2185 
  2186 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2187 translates to the operator "split";
  2188 
  2189 
  2190 
  2191 New in Isabelle94-3
  2192 -------------------
  2193 
  2194 * new infix operator, addss, allowing the classical reasoner to
  2195 perform simplification at each step of its search.  Example:
  2196         fast_tac (cs addss ss)
  2197 
  2198 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2199 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2200 look like (a,b) instead of <a,b>;
  2201 
  2202 * PLEASE NOTE: CHOL will eventually replace HOL!
  2203 
  2204 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2205 It translates to the operator "split".  A new theory of integers is available;
  2206 
  2207 * In ZF, integer numerals now denote two's-complement binary integers.
  2208 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2209 
  2210 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2211 of the Axiom of Choice;
  2212 
  2213 
  2214 
  2215 New in Isabelle94-2
  2216 -------------------
  2217 
  2218 * Significantly faster resolution;
  2219 
  2220 * the different sections in a .thy file can now be mixed and repeated
  2221 freely;
  2222 
  2223 * Database of theorems for FOL, HOL and ZF.  New
  2224 commands including qed, qed_goal and bind_thm store theorems in the database.
  2225 
  2226 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2227 a given theory (thms_of), or find out what theory a theorem was proved in
  2228 (theory_of_thm);
  2229 
  2230 * Bugs fixed in the inductive definition and datatype packages;
  2231 
  2232 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2233 and HOL_dup_cs obsolete;
  2234 
  2235 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2236 have been removed;
  2237 
  2238 * Simpler definition of function space in ZF;
  2239 
  2240 * new results about cardinal and ordinal arithmetic in ZF;
  2241 
  2242 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2243 types;
  2244 
  2245 
  2246 $Id$