NEWS
author wenzelm
Tue Jul 02 15:54:21 2002 +0200 (2002-07-02)
changeset 13280 306ef3aef61b
parent 13190 172f65d0c3d1
child 13284 20c818c966e6
permissions -rw-r--r--
* improved thms_containing: proper indexing of facts instead of raw
theorems; check validity of results wrt. current name space; include
local facts of proof configuration (also covers active locales);
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in this Isabelle release
     6 ----------------------------
     7 
     8 *** General ***
     9 
    10 * improved thms_containing: proper indexing of facts instead of raw
    11 theorems; check validity of results wrt. current name space; include
    12 local facts of proof configuration (also covers active locales);
    13 
    14 
    15 *** HOL ***
    16 
    17 * arith(_tac) does now know about div k and mod k where k is a numeral of
    18   type nat. It can solve simple goals like "0 < n ==> n div 2 < (n::nat)"
    19   but fails if divisibility plays a role like in
    20   "n div 2 + (n+1) div 2 = (n::nat)".
    21 * simp's arithmetic capabilities have been enhanced a bit:
    22   it now takes ~= in premises into account (by performing a case split).
    23 
    24 
    25 
    26 New in Isabelle2002 (March 2002)
    27 --------------------------------
    28 
    29 *** Document preparation ***
    30 
    31 * greatly simplified document preparation setup, including more
    32 graceful interpretation of isatool usedir -i/-d/-D options, and more
    33 instructive isatool mkdir; users should basically be able to get
    34 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    35 users may run a separate document processing stage manually like this:
    36 "isatool usedir -D output HOL Test && isatool document Test/output";
    37 
    38 * theory dependency graph may now be incorporated into documents;
    39 isatool usedir -g true will produce session_graph.eps/.pdf for use
    40 with \includegraphics of LaTeX;
    41 
    42 * proper spacing of consecutive markup elements, especially text
    43 blocks after section headings;
    44 
    45 * support bold style (for single symbols only), input syntax is like
    46 this: "\<^bold>\<alpha>" or "\<^bold>A";
    47 
    48 * \<bullet> is now output as bold \cdot by default, which looks much
    49 better in printed text;
    50 
    51 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    52 note that these symbols are currently unavailable in Proof General /
    53 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
    54 
    55 * isatool latex no longer depends on changed TEXINPUTS, instead
    56 isatool document copies the Isabelle style files to the target
    57 location;
    58 
    59 
    60 *** Isar ***
    61 
    62 * Pure/Provers: improved proof by cases and induction;
    63   - 'case' command admits impromptu naming of parameters (such as
    64     "case (Suc n)");
    65   - 'induct' method divinates rule instantiation from the inductive
    66     claim; no longer requires excessive ?P bindings for proper
    67     instantiation of cases;
    68   - 'induct' method properly enumerates all possibilities of set/type
    69     rules; as a consequence facts may be also passed through *type*
    70     rules without further ado;
    71   - 'induct' method now derives symbolic cases from the *rulified*
    72     rule (before it used to rulify cases stemming from the internal
    73     atomized version); this means that the context of a non-atomic
    74     statement becomes is included in the hypothesis, avoiding the
    75     slightly cumbersome show "PROP ?case" form;
    76   - 'induct' may now use elim-style induction rules without chaining
    77     facts, using ``missing'' premises from the goal state; this allows
    78     rules stemming from inductive sets to be applied in unstructured
    79     scripts, while still benefitting from proper handling of non-atomic
    80     statements; NB: major inductive premises need to be put first, all
    81     the rest of the goal is passed through the induction;
    82   - 'induct' proper support for mutual induction involving non-atomic
    83     rule statements (uses the new concept of simultaneous goals, see
    84     below);
    85   - append all possible rule selections, but only use the first
    86     success (no backtracking);
    87   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    88   - undeclared rule case names default to numbers 1, 2, 3, ...;
    89   - added 'print_induct_rules' (covered by help item in recent Proof
    90     General versions);
    91   - moved induct/cases attributes to Pure, methods to Provers;
    92   - generic method setup instantiated for FOL and HOL;
    93 
    94 * Pure: support multiple simultaneous goal statements, for example
    95 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    96 meta-level mechanism, this acts as if several individual goals had
    97 been stated separately; in particular common proof methods need to be
    98 repeated in order to cover all claims; note that a single elimination
    99 step is *not* sufficient to establish the two conjunctions, so this
   100 fails:
   101 
   102   assume "A & B" then have A and B ..   (*".." fails*)
   103 
   104 better use "obtain" in situations as above; alternative refer to
   105 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   106 
   107 * Pure: proper integration with ``locales''; unlike the original
   108 version by Florian Kammüller, Isar locales package high-level proof
   109 contexts rather than raw logical ones (e.g. we admit to include
   110 attributes everywhere); operations on locales include merge and
   111 rename; support for implicit arguments (``structures''); simultaneous
   112 type-inference over imports and text; see also HOL/ex/Locales.thy for
   113 some examples;
   114 
   115 * Pure: the following commands have been ``localized'', supporting a
   116 target locale specification "(in name)": 'lemma', 'theorem',
   117 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   118 stored both within the locale and at the theory level (exported and
   119 qualified by the locale name);
   120 
   121 * Pure: theory goals may now be specified in ``long'' form, with
   122 ad-hoc contexts consisting of arbitrary locale elements. for example
   123 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   124 definitions may be given, too); the result is a meta-level rule with
   125 the context elements being discharged in the obvious way;
   126 
   127 * Pure: new proof command 'using' allows to augment currently used
   128 facts after a goal statement ('using' is syntactically analogous to
   129 'apply', but acts on the goal's facts only); this allows chained facts
   130 to be separated into parts given before and after a claim, as in
   131 ``from a and b have C using d and e <proof>'';
   132 
   133 * Pure: renamed "antecedent" case to "rule_context";
   134 
   135 * Pure: new 'judgment' command records explicit information about the
   136 object-logic embedding (used by several tools internally); no longer
   137 use hard-wired "Trueprop";
   138 
   139 * Pure: added 'corollary' command;
   140 
   141 * Pure: fixed 'token_translation' command;
   142 
   143 * Pure: removed obsolete 'exported' attribute;
   144 
   145 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   146 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   147 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   148 
   149 * Pure: method 'atomize' presents local goal premises as object-level
   150 statements (atomic meta-level propositions); setup controlled via
   151 rewrite rules declarations of 'atomize' attribute; example
   152 application: 'induct' method with proper rule statements in improper
   153 proof *scripts*;
   154 
   155 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   156 now consider the syntactic context of assumptions, giving a better
   157 chance to get type-inference of the arguments right (this is
   158 especially important for locales);
   159 
   160 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   161 mode;
   162 
   163 * Pure/obtain: the formal conclusion "thesis", being marked as
   164 ``internal'', may no longer be reference directly in the text;
   165 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   166 situations;
   167 
   168 * Pure: generic 'sym' attribute which declares a rule both as pure
   169 'elim?' and for the 'symmetric' operation;
   170 
   171 * Pure: marginal comments ``--'' may now occur just anywhere in the
   172 text; the fixed correlation with particular command syntax has been
   173 discontinued;
   174 
   175 * Pure: new method 'rules' is particularly well-suited for proof
   176 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   177 but often produces more compact proof terms with less detours;
   178 
   179 * Pure/Provers/classical: simplified integration with pure rule
   180 attributes and methods; the classical "intro?/elim?/dest?"
   181 declarations coincide with the pure ones; the "rule" method no longer
   182 includes classically swapped intros; "intro" and "elim" methods no
   183 longer pick rules from the context; also got rid of ML declarations
   184 AddXIs/AddXEs/AddXDs; all of this has some potential for
   185 INCOMPATIBILITY;
   186 
   187 * Provers/classical: attribute 'swapped' produces classical inversions
   188 of introduction rules;
   189 
   190 * Provers/simplifier: 'simplified' attribute may refer to explicit
   191 rules instead of full simplifier context; 'iff' attribute handles
   192 conditional rules;
   193 
   194 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   195 
   196 * HOL: 'recdef' now fails on unfinished automated proofs, use
   197 "(permissive)" option to recover old behavior;
   198 
   199 * HOL: 'inductive' no longer features separate (collective) attributes
   200 for 'intros' (was found too confusing);
   201 
   202 * HOL: properly declared induction rules less_induct and
   203 wf_induct_rule;
   204 
   205 
   206 *** HOL ***
   207 
   208 * HOL: moved over to sane numeral syntax; the new policy is as
   209 follows:
   210 
   211   - 0 and 1 are polymorphic constants, which are defined on any
   212   numeric type (nat, int, real etc.);
   213 
   214   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   215   binary representation internally;
   216 
   217   - type nat has special constructor Suc, and generally prefers Suc 0
   218   over 1::nat and Suc (Suc 0) over 2::nat;
   219 
   220 This change may cause significant problems of INCOMPATIBILITY; here
   221 are some hints on converting existing sources:
   222 
   223   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   224   entities, so expressions involving "-" (unary or binary minus) need
   225   to be spaced properly;
   226 
   227   - existing occurrences of "1" may need to be constraint "1::nat" or
   228   even replaced by Suc 0; similar for old "2";
   229 
   230   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   231 
   232   - remove all special provisions on numerals in proofs;
   233 
   234 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   235 representation (depends on bin_arith_simps in the default context);
   236 
   237 * HOL: symbolic syntax for x^2 (numeral 2);
   238 
   239 * HOL: the class of all HOL types is now called "type" rather than
   240 "term"; INCOMPATIBILITY, need to adapt references to this type class
   241 in axclass/classes, instance/arities, and (usually rare) occurrences
   242 in typings (of consts etc.); internally the class is called
   243 "HOL.type", ML programs should refer to HOLogic.typeS;
   244 
   245 * HOL/record package improvements:
   246   - new derived operations "fields" to build a partial record section,
   247     "extend" to promote a fixed record to a record scheme, and
   248     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   249     declared as simp by default;
   250   - shared operations ("more", "fields", etc.) now need to be always
   251     qualified) --- potential INCOMPATIBILITY;
   252   - removed "make_scheme" operations (use "make" with "extend") --
   253     INCOMPATIBILITY;
   254   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   255   - provides cases/induct rules for use with corresponding Isar
   256     methods (for concrete records, record schemes, concrete more
   257     parts, and schematic more parts -- in that order);
   258   - internal definitions directly based on a light-weight abstract
   259     theory of product types over typedef rather than datatype;
   260 
   261 * HOL: generic code generator for generating executable ML code from
   262 specifications; specific support for HOL constructs such as inductive
   263 datatypes and sets, as well as recursive functions; can be invoked
   264 via 'generate_code' theory section;
   265 
   266 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   267 
   268 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   269 (beware of argument permutation!);
   270 
   271 * HOL: linorder_less_split superseded by linorder_cases;
   272 
   273 * HOL/List: "nodups" renamed to "distinct";
   274 
   275 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   276 to peripheral theory "Hilbert_Choice";
   277 
   278 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   279 in this (rare) case use:
   280 
   281   delSWrapper "split_all_tac"
   282   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   283 
   284 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   285 MAY FAIL;
   286 
   287 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   288 Isabelle's type classes, ^ on functions and relations has too general
   289 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   290 necessary to attach explicit type constraints;
   291 
   292 * HOL/Relation: the prefix name of the infix "O" has been changed from
   293 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   294 renamed accordingly (eg "compI" -> "rel_compI").
   295 
   296 * HOL: syntax translations now work properly with numerals and records
   297 expressions;
   298 
   299 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   300 of "lam" -- INCOMPATIBILITY;
   301 
   302 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   303 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   304 renamed "Product_Type.unit";
   305 
   306 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   307 
   308 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   309 the "cases" method);
   310 
   311 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   312 Florian Kammüller);
   313 
   314 * HOL/IMP: updated and converted to new-style theory format; several
   315 parts turned into readable document, with proper Isar proof texts and
   316 some explanations (by Gerwin Klein);
   317 
   318 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   319 
   320 * HOL-Hyperreal is now a logic image;
   321 
   322 
   323 *** HOLCF ***
   324 
   325 * Isar: consts/constdefs supports mixfix syntax for continuous
   326 operations;
   327 
   328 * Isar: domain package adapted to new-style theory format, e.g. see
   329 HOLCF/ex/Dnat.thy;
   330 
   331 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   332 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   333 lift.induct_tac, always use UU instead of Undef;
   334 
   335 * HOLCF/IMP: updated and converted to new-style theory;
   336 
   337 
   338 *** ZF ***
   339 
   340 * Isar: proper integration of logic-specific tools and packages,
   341 including theory commands '(co)inductive', '(co)datatype',
   342 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   343 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   344 
   345 * theory Main no longer includes AC; for the Axiom of Choice, base
   346 your theory on Main_ZFC;
   347 
   348 * the integer library now covers quotients and remainders, with many
   349 laws relating division to addition, multiplication, etc.;
   350 
   351 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   352 typeless version of the formalism;
   353 
   354 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   355 format;
   356 
   357 * ZF/Induct: new directory for examples of inductive definitions,
   358 including theory Multiset for multiset orderings; converted to
   359 new-style theory format;
   360 
   361 * ZF: many new theorems about lists, ordinals, etc.;
   362 
   363 
   364 *** General ***
   365 
   366 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   367 variable proof controls level of detail: 0 = no proofs (only oracle
   368 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   369 also ref manual for further ML interfaces;
   370 
   371 * Pure/axclass: removed obsolete ML interface
   372 goal_subclass/goal_arity;
   373 
   374 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   375 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   376 separate tokens, so expressions involving minus need to be spaced
   377 properly;
   378 
   379 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   380 rather than "infixl" or "infixr";
   381 
   382 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   383 sort constraint specifications in type inference; e.g. "x::_::foo"
   384 ensures that the type of "x" is of sort "foo" (but not necessarily a
   385 type variable);
   386 
   387 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   388 control output of nested => (types); the default behavior is
   389 "type_brackets";
   390 
   391 * Pure/syntax: builtin parse translation for "_constify" turns valued
   392 tokens into AST constants;
   393 
   394 * Pure/syntax: prefer later declarations of translations and print
   395 translation functions; potential INCOMPATIBILITY: need to reverse
   396 multiple declarations for same syntax element constant;
   397 
   398 * Pure/show_hyps reset by default (in accordance to existing Isar
   399 practice);
   400 
   401 * Provers/classical: renamed addaltern to addafter, addSaltern to
   402 addSafter;
   403 
   404 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   405 as well;
   406 
   407 * system: tested support for MacOS X; should be able to get Isabelle +
   408 Proof General to work in a plain Terminal after installing Poly/ML
   409 (e.g. from the Isabelle distribution area) and GNU bash alone
   410 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   411 support requires further installations, e.g. from
   412 http://fink.sourceforge.net/);
   413 
   414 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   415 
   416 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   417 of 40 MB), cf. ML_OPTIONS;
   418 
   419 * system: Proof General keywords specification is now part of the
   420 Isabelle distribution (see etc/isar-keywords.el);
   421 
   422 * system: support for persistent Proof General sessions (refrain from
   423 outdating all loaded theories on startup); user may create writable
   424 logic images like this: ``isabelle -q HOL Test'';
   425 
   426 * system: smart selection of Isabelle process versus Isabelle
   427 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   428 run both "isabelle" and "Isabelle" even if file names are badly
   429 damaged (executable inspects the case of the first letter of its own
   430 name); added separate "isabelle-process" and "isabelle-interface";
   431 
   432 * system: refrain from any attempt at filtering input streams; no
   433 longer support ``8bit'' encoding of old isabelle font, instead proper
   434 iso-latin characters may now be used; the related isatools
   435 "symbolinput" and "nonascii" have disappeared as well;
   436 
   437 * system: removed old "xterm" interface (the print modes "xterm" and
   438 "xterm_color" are still available for direct use in a suitable
   439 terminal);
   440 
   441 
   442 
   443 New in Isabelle99-2 (February 2001)
   444 -----------------------------------
   445 
   446 *** Overview of INCOMPATIBILITIES ***
   447 
   448 * HOL: please note that theories in the Library and elsewhere often use the
   449 new-style (Isar) format; to refer to their theorems in an ML script you must
   450 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   451 
   452 * HOL: inductive package no longer splits induction rule aggressively,
   453 but only as far as specified by the introductions given; the old
   454 format may be recovered via ML function complete_split_rule or attribute
   455 'split_rule (complete)';
   456 
   457 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   458 gfp_Tarski to gfp_unfold;
   459 
   460 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   461 
   462 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   463 relation); infix "^^" has been renamed "``"; infix "``" has been
   464 renamed "`"; "univalent" has been renamed "single_valued";
   465 
   466 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   467 operation;
   468 
   469 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   470 
   471 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   472 
   473 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   474 consequence, it is no longer monotonic wrt. the local goal context
   475 (which is now passed through the inductive cases);
   476 
   477 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   478 \<gg> to \<ggreater>;
   479 
   480 
   481 *** Document preparation ***
   482 
   483 * \isabellestyle{NAME} selects version of Isabelle output (currently
   484 available: are "it" for near math-mode best-style output, "sl" for
   485 slanted text style, and "tt" for plain type-writer; if no
   486 \isabellestyle command is given, output is according to slanted
   487 type-writer);
   488 
   489 * support sub/super scripts (for single symbols only), input syntax is
   490 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   491 
   492 * some more standard symbols; see Appendix A of the system manual for
   493 the complete list of symbols defined in isabellesym.sty;
   494 
   495 * improved isabelle style files; more abstract symbol implementation
   496 (should now use \isamath{...} and \isatext{...} in custom symbol
   497 definitions);
   498 
   499 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   500 state; Note that presentation of goal states does not conform to
   501 actual human-readable proof documents.  Please do not include goal
   502 states into document output unless you really know what you are doing!
   503 
   504 * proper indentation of antiquoted output with proportional LaTeX
   505 fonts;
   506 
   507 * no_document ML operator temporarily disables LaTeX document
   508 generation;
   509 
   510 * isatool unsymbolize tunes sources for plain ASCII communication;
   511 
   512 
   513 *** Isar ***
   514 
   515 * Pure: Isar now suffers initial goal statements to contain unbound
   516 schematic variables (this does not conform to actual readable proof
   517 documents, due to unpredictable outcome and non-compositional proof
   518 checking); users who know what they are doing may use schematic goals
   519 for Prolog-style synthesis of proven results;
   520 
   521 * Pure: assumption method (an implicit finishing) now handles actual
   522 rules as well;
   523 
   524 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   525 initial goal, declare "that" only as Pure intro (only for single
   526 steps); the "that" rule assumption may now be involved in implicit
   527 finishing, thus ".." becomes a feasible for trivial obtains;
   528 
   529 * Pure: default proof step now includes 'intro_classes'; thus trivial
   530 instance proofs may be performed by "..";
   531 
   532 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   533 statements as well;
   534 
   535 * Pure: more robust selection of calculational rules;
   536 
   537 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   538 rule (as well as the assumption rule);
   539 
   540 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   541 lemmas, using the graph browser tool;
   542 
   543 * Pure: predict failure of "show" in interactive mode;
   544 
   545 * Pure: 'thms_containing' now takes actual terms as arguments;
   546 
   547 * HOL: improved method 'induct' --- now handles non-atomic goals
   548 (potential INCOMPATIBILITY); tuned error handling;
   549 
   550 * HOL: cases and induct rules now provide explicit hints about the
   551 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   552 any remaining facts are inserted into the goal verbatim;
   553 
   554 * HOL: local contexts (aka cases) may now contain term bindings as
   555 well; the 'cases' and 'induct' methods new provide a ?case binding for
   556 the result to be shown in each case;
   557 
   558 * HOL: added 'recdef_tc' command;
   559 
   560 * isatool convert assists in eliminating legacy ML scripts;
   561 
   562 
   563 *** HOL ***
   564 
   565 * HOL/Library: a collection of generic theories to be used together
   566 with main HOL; the theory loader path already includes this directory
   567 by default; the following existing theories have been moved here:
   568 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   569 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   570 
   571 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   572 modelling and verification task performed in Isabelle/HOL +
   573 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   574 
   575 * HOL/Algebra: special summation operator SUM no longer exists, it has
   576 been replaced by setsum; infix 'assoc' now has priority 50 (like
   577 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   578 'domain', this makes the theory consistent with mathematical
   579 literature;
   580 
   581 * HOL basics: added overloaded operations "inverse" and "divide"
   582 (infix "/"), syntax for generic "abs" operation, generic summation
   583 operator \<Sum>;
   584 
   585 * HOL/typedef: simplified package, provide more useful rules (see also
   586 HOL/subset.thy);
   587 
   588 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   589 now expressed as a proper nested rule (old-style tactic scripts may
   590 require atomize_strip_tac to cope with non-atomic premises);
   591 
   592 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   593 to "split_conv" (old name still available for compatibility);
   594 
   595 * HOL: improved concrete syntax for strings (e.g. allows translation
   596 rules with string literals);
   597 
   598 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   599  and Fleuriot's mechanization of analysis, including the transcendental
   600  functions for the reals;
   601 
   602 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   603 
   604 
   605 *** CTT ***
   606 
   607 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   608 "lam" is displayed as TWO lambda-symbols
   609 
   610 * CTT: theory Main now available, containing everything (that is, Bool
   611 and Arith);
   612 
   613 
   614 *** General ***
   615 
   616 * Pure: the Simplifier has been implemented properly as a derived rule
   617 outside of the actual kernel (at last!); the overall performance
   618 penalty in practical applications is about 50%, while reliability of
   619 the Isabelle inference kernel has been greatly improved;
   620 
   621 * print modes "brackets" and "no_brackets" control output of nested =>
   622 (types) and ==> (props); the default behaviour is "brackets";
   623 
   624 * Provers: fast_tac (and friends) now handle actual object-logic rules
   625 as assumptions as well;
   626 
   627 * system: support Poly/ML 4.0;
   628 
   629 * system: isatool install handles KDE version 1 or 2;
   630 
   631 
   632 
   633 New in Isabelle99-1 (October 2000)
   634 ----------------------------------
   635 
   636 *** Overview of INCOMPATIBILITIES ***
   637 
   638 * HOL: simplification of natural numbers is much changed; to partly
   639 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   640 issue the following ML commands:
   641 
   642   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   643   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   644 
   645 * HOL: simplification no longer dives into case-expressions; this is
   646 controlled by "t.weak_case_cong" for each datatype t;
   647 
   648 * HOL: nat_less_induct renamed to less_induct;
   649 
   650 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   651 fixsome to patch .thy and .ML sources automatically;
   652 
   653   select_equality  -> some_equality
   654   select_eq_Ex     -> some_eq_ex
   655   selectI2EX       -> someI2_ex
   656   selectI2         -> someI2
   657   selectI          -> someI
   658   select1_equality -> some1_equality
   659   Eps_sym_eq       -> some_sym_eq_trivial
   660   Eps_eq           -> some_eq_trivial
   661 
   662 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   663 
   664 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   665 instead);
   666 
   667 * HOL: the recursion equations generated by 'recdef' are now called
   668 f.simps instead of f.rules;
   669 
   670 * HOL: qed_spec_mp now also handles bounded ALL as well;
   671 
   672 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   673 sometimes be needed;
   674 
   675 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   676 
   677 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   678 
   679 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   680 product is now "<*>" instead of "Times"; the lexicographic product is
   681 now "<*lex*>" instead of "**";
   682 
   683 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   684 of main HOL, but was unused); better use HOL's datatype package;
   685 
   686 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   687 the old syntax may be recovered as follows:
   688 
   689   syntax (symbols)
   690     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   691       (infixl "\\<oplus>" 100)
   692 
   693 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   694 
   695 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   696 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   697 internally;
   698 
   699 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   700 changed from A/r to A//r;
   701 
   702 * ZF: new treatment of arithmetic (nat & int) may break some old
   703 proofs;
   704 
   705 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   706 rulify -> rule_format, elimify -> elim_format, ...);
   707 
   708 * Isar/Provers: intro/elim/dest attributes changed; renamed
   709 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   710 should have to change intro!! to intro? only); replaced "delrule" by
   711 "rule del";
   712 
   713 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   714 
   715 * Provers: strengthened force_tac by using new first_best_tac;
   716 
   717 * LaTeX document preparation: several changes of isabelle.sty (see
   718 lib/texinputs);
   719 
   720 
   721 *** Document preparation ***
   722 
   723 * formal comments (text blocks etc.) in new-style theories may now
   724 contain antiquotations of thm/prop/term/typ/text to be presented
   725 according to latex print mode; concrete syntax is like this:
   726 @{term[show_types] "f(x) = a + x"};
   727 
   728 * isatool mkdir provides easy setup of Isabelle session directories,
   729 including proper document sources;
   730 
   731 * generated LaTeX sources are now deleted after successful run
   732 (isatool document -c); may retain a copy somewhere else via -D option
   733 of isatool usedir;
   734 
   735 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   736 style files, achieving self-contained LaTeX sources and simplifying
   737 LaTeX debugging;
   738 
   739 * old-style theories now produce (crude) LaTeX output as well;
   740 
   741 * browser info session directories are now self-contained (may be put
   742 on WWW server seperately); improved graphs of nested sessions; removed
   743 graph for 'all sessions';
   744 
   745 * several improvements in isabelle style files; \isabellestyle{it}
   746 produces fake math mode output; \isamarkupheader is now \section by
   747 default; see lib/texinputs/isabelle.sty etc.;
   748 
   749 
   750 *** Isar ***
   751 
   752 * Isar/Pure: local results and corresponding term bindings are now
   753 subject to Hindley-Milner polymorphism (similar to ML); this
   754 accommodates incremental type-inference very nicely;
   755 
   756 * Isar/Pure: new derived language element 'obtain' supports
   757 generalized existence reasoning;
   758 
   759 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   760 support accumulation of results, without applying any rules yet;
   761 useful to collect intermediate results without explicit name
   762 references, and for use with transitivity rules with more than 2
   763 premises;
   764 
   765 * Isar/Pure: scalable support for case-analysis type proofs: new
   766 'case' language element refers to local contexts symbolically, as
   767 produced by certain proof methods; internally, case names are attached
   768 to theorems as "tags";
   769 
   770 * Isar/Pure: theory command 'hide' removes declarations from
   771 class/type/const name spaces;
   772 
   773 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   774 indicate potential overloading;
   775 
   776 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   777 
   778 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   779 "{a,b,c}" instead of {a,b,c};
   780 
   781 * Isar/Pure now provides its own version of intro/elim/dest
   782 attributes; useful for building new logics, but beware of confusion
   783 with the version in Provers/classical;
   784 
   785 * Isar/Pure: the local context of (non-atomic) goals is provided via
   786 case name 'antecedent';
   787 
   788 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   789 to the current context is now done automatically);
   790 
   791 * Isar/Pure: theory command 'method_setup' provides a simple interface
   792 for definining proof methods in ML;
   793 
   794 * Isar/Provers: intro/elim/dest attributes changed; renamed
   795 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   796 most cases, one should have to change intro!! to intro? only);
   797 replaced "delrule" by "rule del";
   798 
   799 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   800 'symmetric' attribute (the latter supercedes [RS sym]);
   801 
   802 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   803 method modifier); 'simp' method: 'only:' modifier removes loopers as
   804 well (including splits);
   805 
   806 * Isar/Provers: Simplifier and Classical methods now support all kind
   807 of modifiers used in the past, including 'cong', 'iff', etc.
   808 
   809 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   810 of Simplifier and Classical reasoner);
   811 
   812 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   813 now support named cases; major packages (inductive, datatype, primrec,
   814 recdef) support case names and properly name parameters;
   815 
   816 * Isar/HOL: new transitivity rules for substitution in inequalities --
   817 monotonicity conditions are extracted to be proven at end of
   818 calculations;
   819 
   820 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   821 method anyway;
   822 
   823 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   824 split_if split_if_asm; datatype package provides theorems foo.splits =
   825 foo.split foo.split_asm for each datatype;
   826 
   827 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   828 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   829 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   830 use "(cases (simplified))" method in proper proof texts);
   831 
   832 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   833 
   834 * Isar: names of theorems etc. may be natural numbers as well;
   835 
   836 * Isar: 'pr' command: optional arguments for goals_limit and
   837 ProofContext.prems_limit; no longer prints theory contexts, but only
   838 proof states;
   839 
   840 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   841 additional print modes to be specified; e.g. "pr(latex)" will print
   842 proof state according to the Isabelle LaTeX style;
   843 
   844 * Isar: improved support for emulating tactic scripts, including proof
   845 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   846 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   847 (for HOL datatypes);
   848 
   849 * Isar: simplified (more robust) goal selection of proof methods: 1st
   850 goal, all goals, or explicit goal specifier (tactic emulation); thus
   851 'proof method scripts' have to be in depth-first order;
   852 
   853 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   854 
   855 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   856 should instead use individual commands for printing items
   857 (print_commands, print_methods etc.);
   858 
   859 * Isar: added 'nothing' --- the empty list of theorems;
   860 
   861 
   862 *** HOL ***
   863 
   864 * HOL/MicroJava: formalization of a fragment of Java, together with a
   865 corresponding virtual machine and a specification of its bytecode
   866 verifier and a lightweight bytecode verifier, including proofs of
   867 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   868 Cornelia Pusch (see also the homepage of project Bali at
   869 http://isabelle.in.tum.de/Bali/);
   870 
   871 * HOL/Algebra: new theory of rings and univariate polynomials, by
   872 Clemens Ballarin;
   873 
   874 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   875 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   876 Rasmussen;
   877 
   878 * HOL/Lattice: fundamental concepts of lattice theory and order
   879 structures, including duals, properties of bounds versus algebraic
   880 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   881 Theorem for complete lattices etc.; may also serve as a demonstration
   882 for abstract algebraic reasoning using axiomatic type classes, and
   883 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   884 
   885 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   886 von Oheimb;
   887 
   888 * HOL/IMPP: extension of IMP with local variables and mutually
   889 recursive procedures, by David von Oheimb;
   890 
   891 * HOL/Lambda: converted into new-style theory and document;
   892 
   893 * HOL/ex/Multiquote: example of multiple nested quotations and
   894 anti-quotations -- basically a generalized version of de-Bruijn
   895 representation; very useful in avoiding lifting of operations;
   896 
   897 * HOL/record: added general record equality rule to simpset; fixed
   898 select-update simplification procedure to handle extended records as
   899 well; admit "r" as field name;
   900 
   901 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   902 other numeric types and also as the identity of groups, rings, etc.;
   903 
   904 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   905 Types nat and int belong to this axclass;
   906 
   907 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   908    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   909    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   910   two terms #m*u and #n*u are replaced by #(m+n)*u
   911     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   912   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   913     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   914 
   915 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   916 powerful prover for predicate logic but knows nothing of clasets; see
   917 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   918 
   919 * HOL: new version of "case_tac" subsumes both boolean case split and
   920 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   921 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   922 
   923 * HOL: simplification no longer dives into case-expressions: only the
   924 selector expression is simplified, but not the remaining arms; to
   925 enable full simplification of case-expressions for datatype t, you may
   926 remove t.weak_case_cong from the simpset, either globally (Delcongs
   927 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   928 
   929 * HOL/recdef: the recursion equations generated by 'recdef' for
   930 function 'f' are now called f.simps instead of f.rules; if all
   931 termination conditions are proved automatically, these simplification
   932 rules are added to the simpset, as in primrec; rules may be named
   933 individually as well, resulting in a separate list of theorems for
   934 each equation;
   935 
   936 * HOL/While is a new theory that provides a while-combinator. It
   937 permits the definition of tail-recursive functions without the
   938 provision of a termination measure. The latter is necessary once the
   939 invariant proof rule for while is applied.
   940 
   941 * HOL: new (overloaded) notation for the set of elements below/above
   942 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   943 
   944 * HOL: theorems impI, allI, ballI bound as "strip";
   945 
   946 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   947 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   948 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   949 
   950 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   951 
   952 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   953 main HOL, but was unused);
   954 
   955 * HOL: fewer consts declared as global (e.g. have to refer to
   956 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   957 
   958 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   959 in case of overlap with user translations (e.g. judgements over
   960 tuples); (note that the underlying logical represenation is still
   961 bogus);
   962 
   963 
   964 *** ZF ***
   965 
   966 * ZF: simplification automatically cancels common terms in arithmetic
   967 expressions over nat and int;
   968 
   969 * ZF: new treatment of nat to minimize type-checking: all operators
   970 coerce their operands to a natural number using the function natify,
   971 making the algebraic laws unconditional;
   972 
   973 * ZF: as above, for int: operators coerce their operands to an integer
   974 using the function intify;
   975 
   976 * ZF: the integer library now contains many of the usual laws for the
   977 orderings, including $<=, and monotonicity laws for $+ and $*;
   978 
   979 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   980 simplification;
   981 
   982 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   983 to the simplifier and classical reasoner simultaneously;
   984 
   985 
   986 *** General ***
   987 
   988 * Provers: blast_tac now handles actual object-logic rules as
   989 assumptions; note that auto_tac uses blast_tac internally as well;
   990 
   991 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   992 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   993 
   994 * Provers: delrules now handles destruct rules as well (no longer need
   995 explicit make_elim);
   996 
   997 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   998   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   999 use instead the strong form,
  1000   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1001 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1002 from destruct-rules;
  1003 
  1004 * Provers: Simplifier.easy_setup provides a fast path to basic
  1005 Simplifier setup for new object-logics;
  1006 
  1007 * Pure: AST translation rules no longer require constant head on LHS;
  1008 
  1009 * Pure: improved name spaces: ambiguous output is qualified; support
  1010 for hiding of names;
  1011 
  1012 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1013 XSYMBOL_HOME; no longer need to do manual configuration in most
  1014 situations;
  1015 
  1016 * system: compression of ML heaps images may now be controlled via -c
  1017 option of isabelle and isatool usedir (currently only observed by
  1018 Poly/ML);
  1019 
  1020 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1021 useful for remote X11);
  1022 
  1023 * system: provide TAGS file for Isabelle sources;
  1024 
  1025 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1026 order;
  1027 
  1028 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1029 timing flag supersedes proof_timing and Toplevel.trace;
  1030 
  1031 * ML: new combinators |>> and |>>> for incremental transformations
  1032 with secondary results (e.g. certain theory extensions):
  1033 
  1034 * ML: PureThy.add_defs gets additional argument to indicate potential
  1035 overloading (usually false);
  1036 
  1037 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1038 results;
  1039 
  1040 
  1041 
  1042 New in Isabelle99 (October 1999)
  1043 --------------------------------
  1044 
  1045 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1046 
  1047 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1048 are no longer simplified.  (This allows the simplifier to unfold recursive
  1049 functional programs.)  To restore the old behaviour, declare
  1050 
  1051     Delcongs [if_weak_cong];
  1052 
  1053 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1054 complement;
  1055 
  1056 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1057 
  1058 * HOL/datatype: mutual_induct_tac no longer exists --
  1059   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1060 
  1061 * HOL/typedef: fixed type inference for representing set; type
  1062 arguments now have to occur explicitly on the rhs as type constraints;
  1063 
  1064 * ZF: The con_defs part of an inductive definition may no longer refer
  1065 to constants declared in the same theory;
  1066 
  1067 * HOL, ZF: the function mk_cases, generated by the inductive
  1068 definition package, has lost an argument.  To simplify its result, it
  1069 uses the default simpset instead of a supplied list of theorems.
  1070 
  1071 * HOL/List: the constructors of type list are now Nil and Cons;
  1072 
  1073 * Simplifier: the type of the infix ML functions
  1074         setSSolver addSSolver setSolver addSolver
  1075 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1076 for packaging solvers. A solver is created via
  1077         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1078 where the string argument is only a comment.
  1079 
  1080 
  1081 *** Proof tools ***
  1082 
  1083 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1084 decision procedure for linear arithmetic. Currently it is used for
  1085 types `nat', `int', and `real' in HOL (see below); it can, should and
  1086 will be instantiated for other types and logics as well.
  1087 
  1088 * The simplifier now accepts rewrite rules with flexible heads, eg
  1089      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1090   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1091   matching.
  1092 
  1093 
  1094 *** General ***
  1095 
  1096 * New Isabelle/Isar subsystem provides an alternative to traditional
  1097 tactical theorem proving; together with the ProofGeneral/isar user
  1098 interface it offers an interactive environment for developing human
  1099 readable proof documents (Isar == Intelligible semi-automated
  1100 reasoning); for further information see isatool doc isar-ref,
  1101 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1102 
  1103 * improved and simplified presentation of theories: better HTML markup
  1104 (including colors), graph views in several sizes; isatool usedir now
  1105 provides a proper interface for user theories (via -P option); actual
  1106 document preparation based on (PDF)LaTeX is available as well (for
  1107 new-style theories only); see isatool doc system for more information;
  1108 
  1109 * native support for Proof General, both for classic Isabelle and
  1110 Isabelle/Isar;
  1111 
  1112 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1113 using the graph browser tool;
  1114 
  1115 * Isabelle manuals now also available as PDF;
  1116 
  1117 * theory loader rewritten from scratch (may not be fully
  1118 bug-compatible); old loadpath variable has been replaced by show_path,
  1119 add_path, del_path, reset_path functions; new operations such as
  1120 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1121 isatool doc ref);
  1122 
  1123 * improved isatool install: option -k creates KDE application icon,
  1124 option -p DIR installs standalone binaries;
  1125 
  1126 * added ML_PLATFORM setting (useful for cross-platform installations);
  1127 more robust handling of platform specific ML images for SML/NJ;
  1128 
  1129 * the settings environment is now statically scoped, i.e. it is never
  1130 created again in sub-processes invoked from isabelle, isatool, or
  1131 Isabelle;
  1132 
  1133 * path element specification '~~' refers to '$ISABELLE_HOME';
  1134 
  1135 * in locales, the "assumes" and "defines" parts may be omitted if
  1136 empty;
  1137 
  1138 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1139 long arrows);
  1140 
  1141 * new print_mode "HTML";
  1142 
  1143 * new flag show_tags controls display of tags of theorems (which are
  1144 basically just comments that may be attached by some tools);
  1145 
  1146 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1147 mode and goal output format:
  1148 
  1149 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1150 244c244
  1151 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1152 ---
  1153 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1154 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1155 181c181
  1156 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1157 ---
  1158 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1159 
  1160 * function bind_thms stores lists of theorems (cf. bind_thm);
  1161 
  1162 * new shorthand tactics ftac, eatac, datac, fatac;
  1163 
  1164 * qed (and friends) now accept "" as result name; in that case the
  1165 theorem is not stored, but proper checks and presentation of the
  1166 result still apply;
  1167 
  1168 * theorem database now also indexes constants "Trueprop", "all",
  1169 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1170 
  1171 
  1172 *** HOL ***
  1173 
  1174 ** HOL arithmetic **
  1175 
  1176 * There are now decision procedures for linear arithmetic over nat and
  1177 int:
  1178 
  1179 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1180 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1181 are treated as atomic; subformulae not involving type `nat' or `int'
  1182 are ignored; quantified subformulae are ignored unless they are
  1183 positive universal or negative existential. The tactic has to be
  1184 invoked by hand and can be a little bit slow. In particular, the
  1185 running time is exponential in the number of occurrences of `min' and
  1186 `max', and `-' on `nat'.
  1187 
  1188 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1189 (negated) (in)equalities among the premises and the conclusion into
  1190 account (i.e. no compound formulae) and does not know about `min' and
  1191 `max', and `-' on `nat'. It is fast and is used automatically by the
  1192 simplifier.
  1193 
  1194 NB: At the moment, these decision procedures do not cope with mixed
  1195 nat/int formulae where the two parts interact, such as `m < n ==>
  1196 int(m) < int(n)'.
  1197 
  1198 * HOL/Numeral provides a generic theory of numerals (encoded
  1199 efficiently as bit strings); setup for types nat/int/real is in place;
  1200 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1201 int, existing theories and proof scripts may require a few additional
  1202 type constraints;
  1203 
  1204 * integer division and remainder can now be performed on constant
  1205 arguments;
  1206 
  1207 * many properties of integer multiplication, division and remainder
  1208 are now available;
  1209 
  1210 * An interface to the Stanford Validity Checker (SVC) is available through the
  1211 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1212 are proved automatically.  SVC must be installed separately, and its results
  1213 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1214 invocation of the underlying oracle).  For SVC see
  1215   http://verify.stanford.edu/SVC
  1216 
  1217 * IsaMakefile: the HOL-Real target now builds an actual image;
  1218 
  1219 
  1220 ** HOL misc **
  1221 
  1222 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1223 (in Isabelle/Isar) -- by Gertrud Bauer;
  1224 
  1225 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1226 analysis for assembly languages with subtypes;
  1227 
  1228 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1229 -- avoids syntactic ambiguities and treats state, transition, and
  1230 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1231 changed syntax and (many) tactics;
  1232 
  1233 * HOL/inductive: Now also handles more general introduction rules such
  1234   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1235   theorems are now maintained within the theory (maintained via the
  1236   "mono" attribute);
  1237 
  1238 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1239   (using function types) such as
  1240 
  1241   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1242 
  1243 * HOL/record: record_simproc (part of the default simpset) takes care
  1244 of selectors applied to updated records; record_split_tac is no longer
  1245 part of the default claset; update_defs may now be removed from the
  1246 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1247 
  1248   claset_ref () := claset() addSWrapper record_split_wrapper;
  1249   Delsimprocs [record_simproc]
  1250 
  1251 * HOL/typedef: fixed type inference for representing set; type
  1252 arguments now have to occur explicitly on the rhs as type constraints;
  1253 
  1254 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1255 names rather than an ML expression;
  1256 
  1257 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1258 supplied later.  Program schemes can be defined, such as
  1259     "While B C s = (if B s then While B C (C s) else s)"
  1260 where the well-founded relation can be chosen after B and C have been given.
  1261 
  1262 * HOL/List: the constructors of type list are now Nil and Cons;
  1263 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1264 course, ML tools referring to List.list.op # etc. have to be adapted;
  1265 
  1266 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1267 disabled by default; run isabelle with option -m HOL to get back to
  1268 the original Gordon/HOL-style output;
  1269 
  1270 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1271 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1272 
  1273 * HOL basic syntax simplified (more orthogonal): all variants of
  1274 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1275 Eps operator is provided as well: "SOME x. P[x]";
  1276 
  1277 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1278 
  1279 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1280 thus available for user theories;
  1281 
  1282 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1283 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1284 time;
  1285 
  1286 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1287 several times and then mp;
  1288 
  1289 
  1290 *** LK ***
  1291 
  1292 * the notation <<...>> is now available as a notation for sequences of
  1293 formulas;
  1294 
  1295 * the simplifier is now installed
  1296 
  1297 * the axiom system has been generalized (thanks to Soren Heilmann)
  1298 
  1299 * the classical reasoner now has a default rule database
  1300 
  1301 
  1302 *** ZF ***
  1303 
  1304 * new primrec section allows primitive recursive functions to be given
  1305 directly (as in HOL) over datatypes and the natural numbers;
  1306 
  1307 * new tactics induct_tac and exhaust_tac for induction (or case
  1308 analysis) over datatypes and the natural numbers;
  1309 
  1310 * the datatype declaration of type T now defines the recursor T_rec;
  1311 
  1312 * simplification automatically does freeness reasoning for datatype
  1313 constructors;
  1314 
  1315 * automatic type-inference, with AddTCs command to insert new
  1316 type-checking rules;
  1317 
  1318 * datatype introduction rules are now added as Safe Introduction rules
  1319 to the claset;
  1320 
  1321 * the syntax "if P then x else y" is now available in addition to
  1322 if(P,x,y);
  1323 
  1324 
  1325 *** Internal programming interfaces ***
  1326 
  1327 * tuned simplifier trace output; new flag debug_simp;
  1328 
  1329 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1330 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1331 
  1332 * AxClass.axclass_tac lost the theory argument;
  1333 
  1334 * tuned current_goals_markers semantics: begin / end goal avoids
  1335 printing empty lines;
  1336 
  1337 * removed prs and prs_fn hook, which was broken because it did not
  1338 include \n in its semantics, forcing writeln to add one
  1339 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1340 string -> unit if you really want to output text without newline;
  1341 
  1342 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1343 plain output, interface builders may have to enable 'isabelle_font'
  1344 mode to get Isabelle font glyphs as before;
  1345 
  1346 * refined token_translation interface; INCOMPATIBILITY: output length
  1347 now of type real instead of int;
  1348 
  1349 * theory loader actions may be traced via new ThyInfo.add_hook
  1350 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1351 your own database of information attached to *whole* theories -- as
  1352 opposed to intra-theory data slots offered via TheoryDataFun;
  1353 
  1354 * proper handling of dangling sort hypotheses (at last!);
  1355 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1356 extra sort hypotheses that can be witnessed from the type signature;
  1357 the force_strip_shyps flag is gone, any remaining shyps are simply
  1358 left in the theorem (with a warning issued by strip_shyps_warning);
  1359 
  1360 
  1361 
  1362 New in Isabelle98-1 (October 1998)
  1363 ----------------------------------
  1364 
  1365 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1366 
  1367 * several changes of automated proof tools;
  1368 
  1369 * HOL: major changes to the inductive and datatype packages, including
  1370 some minor incompatibilities of theory syntax;
  1371 
  1372 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1373 called `inj_on';
  1374 
  1375 * HOL: removed duplicate thms in Arith:
  1376   less_imp_add_less  should be replaced by  trans_less_add1
  1377   le_imp_add_le      should be replaced by  trans_le_add1
  1378 
  1379 * HOL: unary minus is now overloaded (new type constraints may be
  1380 required);
  1381 
  1382 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1383 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1384 now taken as an integer constant.
  1385 
  1386 * Pure: ML function 'theory_of' renamed to 'theory';
  1387 
  1388 
  1389 *** Proof tools ***
  1390 
  1391 * Simplifier:
  1392   1. Asm_full_simp_tac is now more aggressive.
  1393      1. It will sometimes reorient premises if that increases their power to
  1394         simplify.
  1395      2. It does no longer proceed strictly from left to right but may also
  1396         rotate premises to achieve further simplification.
  1397      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1398      old Asm_full_simp_tac in that it does not rotate premises.
  1399   2. The simplifier now knows a little bit about nat-arithmetic.
  1400 
  1401 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1402 allows for selected deletion of wrappers, by introduction of names for
  1403 wrapper functionals.  This implies that addbefore, addSbefore,
  1404 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1405 and that adding two tactics with the same name overwrites the first
  1406 one (emitting a warning).
  1407   type wrapper = (int -> tactic) -> (int -> tactic)
  1408   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1409   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1410   delWrapper, delSWrapper: claset *  string            -> claset
  1411   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1412 
  1413 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1414 semantics; addbefore now affects only the unsafe part of step_tac
  1415 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1416 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1417 by Force_tac;
  1418 
  1419 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1420 compWrapper; added safe wrapper (and access functions for it);
  1421 
  1422 * HOL/split_all_tac is now much faster and fails if there is nothing
  1423 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1424 and the names of the automatically generated variables have changed.
  1425 split_all_tac has moved within claset() from unsafe wrappers to safe
  1426 wrappers, which means that !!-bound variables are split much more
  1427 aggressively, and safe_tac and clarify_tac now split such variables.
  1428 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1429 Note: the same holds for record_split_tac, which does the job of
  1430 split_all_tac for record fields.
  1431 
  1432 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1433 permanently to the default simpset using Addsplits just like
  1434 Addsimps. They can be removed via Delsplits just like
  1435 Delsimps. Lower-case versions are also available.
  1436 
  1437 * HOL/Simplifier: The rule split_if is now part of the default
  1438 simpset. This means that the simplifier will eliminate all occurrences
  1439 of if-then-else in the conclusion of a goal. To prevent this, you can
  1440 either remove split_if completely from the default simpset by
  1441 `Delsplits [split_if]' or remove it in a specific call of the
  1442 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1443 other case splitting rules to/from the default simpset: every datatype
  1444 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1445 t is the name of the datatype).
  1446 
  1447 * Classical reasoner / Simplifier combination: new force_tac (and
  1448 derivatives Force_tac, force) combines rewriting and classical
  1449 reasoning (and whatever other tools) similarly to auto_tac, but is
  1450 aimed to solve the given subgoal completely.
  1451 
  1452 
  1453 *** General ***
  1454 
  1455 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1456 and `goalw': the theory is no longer needed as an explicit argument -
  1457 the current theory context is used; assumptions are no longer returned
  1458 at the ML-level unless one of them starts with ==> or !!; it is
  1459 recommended to convert to these new commands using isatool fixgoal
  1460 (backup your sources first!);
  1461 
  1462 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1463 the current theory context, and 'theory' to lookup stored theories;
  1464 
  1465 * new theory section 'locale' for declaring constants, assumptions and
  1466 definitions that have local scope;
  1467 
  1468 * new theory section 'nonterminals' for purely syntactic types;
  1469 
  1470 * new theory section 'setup' for generic ML setup functions
  1471 (e.g. package initialization);
  1472 
  1473 * the distribution now includes Isabelle icons: see
  1474 lib/logo/isabelle-{small,tiny}.xpm;
  1475 
  1476 * isatool install - install binaries with absolute references to
  1477 ISABELLE_HOME/bin;
  1478 
  1479 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1480 
  1481 * print mode 'emacs' reserved for Isamode;
  1482 
  1483 * support multiple print (ast) translations per constant name;
  1484 
  1485 * theorems involving oracles are now printed with a suffixed [!];
  1486 
  1487 
  1488 *** HOL ***
  1489 
  1490 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1491 
  1492 * HOL/inductive package reorganized and improved: now supports mutual
  1493 definitions such as
  1494 
  1495   inductive EVEN ODD
  1496     intrs
  1497       null "0 : EVEN"
  1498       oddI "n : EVEN ==> Suc n : ODD"
  1499       evenI "n : ODD ==> Suc n : EVEN"
  1500 
  1501 new theorem list "elims" contains an elimination rule for each of the
  1502 recursive sets; inductive definitions now handle disjunctive premises
  1503 correctly (also ZF);
  1504 
  1505 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1506 "mutual_induct" no longer exists - the induction rule is always
  1507 contained in "induct";
  1508 
  1509 
  1510 * HOL/datatype package re-implemented and greatly improved: now
  1511 supports mutually recursive datatypes such as
  1512 
  1513   datatype
  1514     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1515             | SUM ('a aexp) ('a aexp)
  1516             | DIFF ('a aexp) ('a aexp)
  1517             | NUM 'a
  1518   and
  1519     'a bexp = LESS ('a aexp) ('a aexp)
  1520             | AND ('a bexp) ('a bexp)
  1521             | OR ('a bexp) ('a bexp)
  1522 
  1523 as well as indirectly recursive datatypes such as
  1524 
  1525   datatype
  1526     ('a, 'b) term = Var 'a
  1527                   | App 'b ((('a, 'b) term) list)
  1528 
  1529 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1530 induction on mutually / indirectly recursive datatypes.
  1531 
  1532 Primrec equations are now stored in theory and can be accessed via
  1533 <function_name>.simps.
  1534 
  1535 INCOMPATIBILITIES:
  1536 
  1537   - Theories using datatypes must now have theory Datatype as an
  1538     ancestor.
  1539   - The specific <typename>.induct_tac no longer exists - use the
  1540     generic induct_tac instead.
  1541   - natE has been renamed to nat.exhaust - use exhaust_tac
  1542     instead of res_inst_tac ... natE. Note that the variable
  1543     names in nat.exhaust differ from the names in natE, this
  1544     may cause some "fragile" proofs to fail.
  1545   - The theorems split_<typename>_case and split_<typename>_case_asm
  1546     have been renamed to <typename>.split and <typename>.split_asm.
  1547   - Since default sorts of type variables are now handled correctly,
  1548     some datatype definitions may have to be annotated with explicit
  1549     sort constraints.
  1550   - Primrec definitions no longer require function name and type
  1551     of recursive argument.
  1552 
  1553 Consider using isatool fixdatatype to adapt your theories and proof
  1554 scripts to the new package (backup your sources first!).
  1555 
  1556 
  1557 * HOL/record package: considerably improved implementation; now
  1558 includes concrete syntax for record types, terms, updates; theorems
  1559 for surjective pairing and splitting !!-bound record variables; proof
  1560 support is as follows:
  1561 
  1562   1) standard conversions (selectors or updates applied to record
  1563 constructor terms) are part of the standard simpset;
  1564 
  1565   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1566 made part of standard simpset and claset via addIffs;
  1567 
  1568   3) a tactic for record field splitting (record_split_tac) is part of
  1569 the standard claset (addSWrapper);
  1570 
  1571 To get a better idea about these rules you may retrieve them via
  1572 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1573 the name of your record type.
  1574 
  1575 The split tactic 3) conceptually simplifies by the following rule:
  1576 
  1577   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1578 
  1579 Thus any record variable that is bound by meta-all will automatically
  1580 blow up into some record constructor term, consequently the
  1581 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1582 solve record problems automatically.
  1583 
  1584 
  1585 * reorganized the main HOL image: HOL/Integ and String loaded by
  1586 default; theory Main includes everything;
  1587 
  1588 * automatic simplification of integer sums and comparisons, using cancellation;
  1589 
  1590 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1591 
  1592 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1593 
  1594 * many new identities for unions, intersections, set difference, etc.;
  1595 
  1596 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1597 called split_if, split_split, split_sum_case and split_nat_case (to go
  1598 with add/delsplits);
  1599 
  1600 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1601 (?x::unit) = (); this is made part of the default simpset, which COULD
  1602 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1603 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1604 unit_abs_eta_conv is added in order to counter the effect of
  1605 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1606 %u.f();
  1607 
  1608 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1609 makes more sense);
  1610 
  1611 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1612   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1613   disjointness reasoning but breaking a few old proofs.
  1614 
  1615 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1616 to 'converse' from 'inverse' (for compatibility with ZF and some
  1617 literature);
  1618 
  1619 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1620 the well-founded relation;
  1621 
  1622 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1623     Compl A.  The "Compl" syntax remains available as input syntax for this
  1624     release ONLY.
  1625 
  1626 * HOL/Update: new theory of function updates:
  1627     f(a:=b) == %x. if x=a then b else f x
  1628 may also be iterated as in f(a:=b,c:=d,...);
  1629 
  1630 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1631 
  1632 * HOL/List:
  1633   - new function list_update written xs[i:=v] that updates the i-th
  1634     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1635   - new function `upt' written [i..j(] which generates the list
  1636     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1637     bound write [i..j], which is a shorthand for [i..j+1(].
  1638   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1639 
  1640 * HOL/Arith:
  1641   - removed 'pred' (predecessor) function;
  1642   - generalized some theorems about n-1;
  1643   - many new laws about "div" and "mod";
  1644   - new laws about greatest common divisors (see theory ex/Primes);
  1645 
  1646 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1647 instead of "inverse";
  1648 
  1649 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1650   of the multiset ordering;
  1651 
  1652 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1653   (not included by default);
  1654 
  1655 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1656 
  1657 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1658   programs, i.e. different program variables may have different types.
  1659 
  1660 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1661   [previously, this check worked only if the rewrite rule was unconditional]
  1662   Now rew can involve either definitions or equalities (either == or =).
  1663 
  1664 
  1665 *** ZF ***
  1666 
  1667 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1668   only the theorems proved on ZF.ML;
  1669 
  1670 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1671   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1672   disjointness reasoning but breaking a few old proofs.
  1673 
  1674 * ZF/Update: new theory of function updates
  1675     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1676   may also be iterated as in f(a:=b,c:=d,...);
  1677 
  1678 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1679 
  1680 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1681   [previously, this check worked only if the rewrite rule was unconditional]
  1682   Now rew can involve either definitions or equalities (either == or =).
  1683 
  1684 * case_tac provided for compatibility with HOL
  1685     (like the old excluded_middle_tac, but with subgoals swapped)
  1686 
  1687 
  1688 *** Internal programming interfaces ***
  1689 
  1690 * Pure: several new basic modules made available for general use, see
  1691 also src/Pure/README;
  1692 
  1693 * improved the theory data mechanism to support encapsulation (data
  1694 kind name replaced by private Object.kind, acting as authorization
  1695 key); new type-safe user interface via functor TheoryDataFun; generic
  1696 print_data function becomes basically useless;
  1697 
  1698 * removed global_names compatibility flag -- all theory declarations
  1699 are qualified by default;
  1700 
  1701 * module Pure/Syntax now offers quote / antiquote translation
  1702 functions (useful for Hoare logic etc. with implicit dependencies);
  1703 see HOL/ex/Antiquote for an example use;
  1704 
  1705 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1706 cterm -> thm;
  1707 
  1708 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1709 subgoal;
  1710 
  1711 * Display.print_goals function moved to Locale.print_goals;
  1712 
  1713 * standard print function for goals supports current_goals_markers
  1714 variable for marking begin of proof, end of proof, start of goal; the
  1715 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1716 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1717 for example;
  1718 
  1719 
  1720 
  1721 New in Isabelle98 (January 1998)
  1722 --------------------------------
  1723 
  1724 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1725 
  1726 * changed lexical syntax of terms / types: dots made part of long
  1727 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1728 
  1729 * simpset (and claset) reference variable replaced by functions
  1730 simpset / simpset_ref;
  1731 
  1732 * no longer supports theory aliases (via merge) and non-trivial
  1733 implicit merge of thms' signatures;
  1734 
  1735 * most internal names of constants changed due to qualified names;
  1736 
  1737 * changed Pure/Sequence interface (see Pure/seq.ML);
  1738 
  1739 
  1740 *** General Changes ***
  1741 
  1742 * hierachically structured name spaces (for consts, types, axms, thms
  1743 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1744 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1745 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1746 long_names for fully qualified output names; NOTE: ML programs
  1747 (special tactics, packages etc.) referring to internal names may have
  1748 to be adapted to cope with fully qualified names; in case of severe
  1749 backward campatibility problems try setting 'global_names' at compile
  1750 time to have enrything declared within a flat name space; one may also
  1751 fine tune name declarations in theories via the 'global' and 'local'
  1752 section;
  1753 
  1754 * reimplemented the implicit simpset and claset using the new anytype
  1755 data filed in signatures; references simpset:simpset ref etc. are
  1756 replaced by functions simpset:unit->simpset and
  1757 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1758 to patch your ML files accordingly;
  1759 
  1760 * HTML output now includes theory graph data for display with Java
  1761 applet or isatool browser; data generated automatically via isatool
  1762 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1763 
  1764 * defs may now be conditional; improved rewrite_goals_tac to handle
  1765 conditional equations;
  1766 
  1767 * defs now admits additional type arguments, using TYPE('a) syntax;
  1768 
  1769 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1770 creates a new theory node; implicit merge of thms' signatures is
  1771 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1772 transfer:theory->thm->thm in (rare) cases;
  1773 
  1774 * improved handling of draft signatures / theories; draft thms (and
  1775 ctyps, cterms) are automatically promoted to real ones;
  1776 
  1777 * slightly changed interfaces for oracles: admit many per theory, named
  1778 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1779 
  1780 * print_goals: optional output of const types (set show_consts and
  1781 show_types);
  1782 
  1783 * improved output of warnings (###) and errors (***);
  1784 
  1785 * subgoal_tac displays a warning if the new subgoal has type variables;
  1786 
  1787 * removed old README and Makefiles;
  1788 
  1789 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1790 
  1791 * removed obsolete init_pps and init_database;
  1792 
  1793 * deleted the obsolete tactical STATE, which was declared by
  1794     fun STATE tacfun st = tacfun st st;
  1795 
  1796 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1797 (which abbreviates $HOME);
  1798 
  1799 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1800 use isatool fixseq to adapt your ML programs (this works for fully
  1801 qualified references to the Sequence structure only!);
  1802 
  1803 * use_thy no longer requires writable current directory; it always
  1804 reloads .ML *and* .thy file, if either one is out of date;
  1805 
  1806 
  1807 *** Classical Reasoner ***
  1808 
  1809 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1810 tactics that use classical reasoning to simplify a subgoal without
  1811 splitting it into several subgoals;
  1812 
  1813 * Safe_tac: like safe_tac but uses the default claset;
  1814 
  1815 
  1816 *** Simplifier ***
  1817 
  1818 * added simplification meta rules:
  1819     (asm_)(full_)simplify: simpset -> thm -> thm;
  1820 
  1821 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1822 logics (again);
  1823 
  1824 * added prems argument to simplification procedures;
  1825 
  1826 * HOL, FOL, ZF: added infix function `addsplits':
  1827   instead of `<simpset> setloop (split_tac <thms>)'
  1828   you can simply write `<simpset> addsplits <thms>'
  1829 
  1830 
  1831 *** Syntax ***
  1832 
  1833 * TYPE('a) syntax for type reflection terms;
  1834 
  1835 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1836 
  1837 * pretty printer: changed order of mixfix annotation preference (again!);
  1838 
  1839 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1840 
  1841 
  1842 *** HOL ***
  1843 
  1844 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1845   with `addloop' of the simplifier to faciliate case splitting in premises.
  1846 
  1847 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1848 
  1849 * HOL/Auth: new protocol proofs including some for the Internet
  1850   protocol TLS;
  1851 
  1852 * HOL/Map: new theory of `maps' a la VDM;
  1853 
  1854 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1855 cancelling out common nat summands from =, <, <= (in)equalities, or
  1856 differences; simplification procedures nat_cancel_factor for
  1857 cancelling common factor from =, <, <= (in)equalities over natural
  1858 sums; nat_cancel contains both kinds of procedures, it is installed by
  1859 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1860 
  1861 * HOL/simplifier: terms of the form
  1862   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1863   are rewritten to
  1864   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1865   and those of the form
  1866   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1867   are rewritten to
  1868   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1869 
  1870 * HOL/datatype
  1871   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1872 
  1873   P(t_case f1 ... fn x) =
  1874      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1875         ...
  1876        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1877      )
  1878 
  1879   and a theorem `split_t_case_asm' of the form
  1880 
  1881   P(t_case f1 ... fn x) =
  1882     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1883         ...
  1884        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1885      )
  1886   which can be added to a simpset via `addsplits'. The existing theorems
  1887   expand_list_case and expand_option_case have been renamed to
  1888   split_list_case and split_option_case.
  1889 
  1890 * HOL/Arithmetic:
  1891   - `pred n' is automatically converted to `n-1'.
  1892     Users are strongly encouraged not to use `pred' any longer,
  1893     because it will disappear altogether at some point.
  1894   - Users are strongly encouraged to write "0 < n" rather than
  1895     "n ~= 0". Theorems and proof tools have been modified towards this
  1896     `standard'.
  1897 
  1898 * HOL/Lists:
  1899   the function "set_of_list" has been renamed "set" (and its theorems too);
  1900   the function "nth" now takes its arguments in the reverse order and
  1901   has acquired the infix notation "!" as in "xs!n".
  1902 
  1903 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1904 
  1905 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1906   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1907 
  1908 * HOL/record: extensible records with schematic structural subtyping
  1909 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1910 still lacks various theorems and concrete record syntax;
  1911 
  1912 
  1913 *** HOLCF ***
  1914 
  1915 * removed "axioms" and "generated by" sections;
  1916 
  1917 * replaced "ops" section by extended "consts" section, which is capable of
  1918   handling the continuous function space "->" directly;
  1919 
  1920 * domain package:
  1921   . proves theorems immediately and stores them in the theory,
  1922   . creates hierachical name space,
  1923   . now uses normal mixfix annotations (instead of cinfix...),
  1924   . minor changes to some names and values (for consistency),
  1925   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1926   . separator between mutual domain defs: changed "," to "and",
  1927   . improved handling of sort constraints;  now they have to
  1928     appear on the left-hand side of the equations only;
  1929 
  1930 * fixed LAM <x,y,zs>.b syntax;
  1931 
  1932 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1933 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1934 
  1935 
  1936 *** FOL and ZF ***
  1937 
  1938 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1939   with `addloop' of the simplifier to faciliate case splitting in premises.
  1940 
  1941 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1942 in HOL, they strip ALL and --> from proved theorems;
  1943 
  1944 
  1945 
  1946 New in Isabelle94-8 (May 1997)
  1947 ------------------------------
  1948 
  1949 *** General Changes ***
  1950 
  1951 * new utilities to build / run / maintain Isabelle etc. (in parts
  1952 still somewhat experimental); old Makefiles etc. still functional;
  1953 
  1954 * new 'Isabelle System Manual';
  1955 
  1956 * INSTALL text, together with ./configure and ./build scripts;
  1957 
  1958 * reimplemented type inference for greater efficiency, better error
  1959 messages and clean internal interface;
  1960 
  1961 * prlim command for dealing with lots of subgoals (an easier way of
  1962 setting goals_limit);
  1963 
  1964 
  1965 *** Syntax ***
  1966 
  1967 * supports alternative (named) syntax tables (parser and pretty
  1968 printer); internal interface is provided by add_modesyntax(_i);
  1969 
  1970 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1971 be used in conjunction with the Isabelle symbol font; uses the
  1972 "symbols" syntax table;
  1973 
  1974 * added token_translation interface (may translate name tokens in
  1975 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1976 the current print_mode); IMPORTANT: user print translation functions
  1977 are responsible for marking newly introduced bounds
  1978 (Syntax.mark_boundT);
  1979 
  1980 * token translations for modes "xterm" and "xterm_color" that display
  1981 names in bold, underline etc. or colors (which requires a color
  1982 version of xterm);
  1983 
  1984 * infixes may now be declared with names independent of their syntax;
  1985 
  1986 * added typed_print_translation (like print_translation, but may
  1987 access type of constant);
  1988 
  1989 
  1990 *** Classical Reasoner ***
  1991 
  1992 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1993 some limitations.  Blast_tac...
  1994   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1995   + ignores elimination rules that don't have the correct format
  1996         (the conclusion MUST be a formula variable)
  1997   + ignores types, which can make HOL proofs fail
  1998   + rules must not require higher-order unification, e.g. apply_type in ZF
  1999     [message "Function Var's argument not a bound variable" relates to this]
  2000   + its proof strategy is more general but can actually be slower
  2001 
  2002 * substitution with equality assumptions no longer permutes other
  2003 assumptions;
  2004 
  2005 * minor changes in semantics of addafter (now called addaltern); renamed
  2006 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2007 (and access functions for it);
  2008 
  2009 * improved combination of classical reasoner and simplifier:
  2010   + functions for handling clasimpsets
  2011   + improvement of addss: now the simplifier is called _after_ the
  2012     safe steps.
  2013   + safe variant of addss called addSss: uses safe simplifications
  2014     _during_ the safe steps. It is more complete as it allows multiple
  2015     instantiations of unknowns (e.g. with slow_tac).
  2016 
  2017 *** Simplifier ***
  2018 
  2019 * added interface for simplification procedures (functions that
  2020 produce *proven* rewrite rules on the fly, depending on current
  2021 redex);
  2022 
  2023 * ordering on terms as parameter (used for ordered rewriting);
  2024 
  2025 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2026 
  2027 * the solver is now split into a safe and an unsafe part.
  2028 This should be invisible for the normal user, except that the
  2029 functions setsolver and addsolver have been renamed to setSolver and
  2030 addSolver; added safe_asm_full_simp_tac;
  2031 
  2032 
  2033 *** HOL ***
  2034 
  2035 * a generic induction tactic `induct_tac' which works for all datatypes and
  2036 also for type `nat';
  2037 
  2038 * a generic case distinction tactic `exhaust_tac' which works for all
  2039 datatypes and also for type `nat';
  2040 
  2041 * each datatype comes with a function `size';
  2042 
  2043 * patterns in case expressions allow tuple patterns as arguments to
  2044 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2045 
  2046 * primrec now also works with type nat;
  2047 
  2048 * recdef: a new declaration form, allows general recursive functions to be
  2049 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2050 
  2051 * the constant for negation has been renamed from "not" to "Not" to
  2052 harmonize with FOL, ZF, LK, etc.;
  2053 
  2054 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2055 infinite lists;
  2056 
  2057 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2058 
  2059 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2060 problems in commutative rings, using axiomatic type classes for + and *;
  2061 
  2062 * more examples in HOL/MiniML and HOL/Auth;
  2063 
  2064 * more default rewrite rules for quantifiers, union/intersection;
  2065 
  2066 * a new constant `arbitrary == @x.False';
  2067 
  2068 * HOLCF/IOA replaces old HOL/IOA;
  2069 
  2070 * HOLCF changes: derived all rules and arities
  2071   + axiomatic type classes instead of classes
  2072   + typedef instead of faking type definitions
  2073   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2074   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2075   + eliminated the types void, one, tr
  2076   + use unit lift and bool lift (with translations) instead of one and tr
  2077   + eliminated blift from Lift3.thy (use Def instead of blift)
  2078   all eliminated rules are derived as theorems --> no visible changes ;
  2079 
  2080 
  2081 *** ZF ***
  2082 
  2083 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2084 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2085 as ZF_cs addSIs [equalityI];
  2086 
  2087 
  2088 
  2089 New in Isabelle94-7 (November 96)
  2090 ---------------------------------
  2091 
  2092 * allowing negative levels (as offsets) in prlev and choplev;
  2093 
  2094 * super-linear speedup for large simplifications;
  2095 
  2096 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2097 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2098 FAIL); can suppress it using the command Delsimps (ex_simps @
  2099 all_simps); De Morgan laws are also now included, by default;
  2100 
  2101 * improved printing of ==>  :  ~:
  2102 
  2103 * new object-logic "Sequents" adds linear logic, while replacing LK
  2104 and Modal (thanks to Sara Kalvala);
  2105 
  2106 * HOL/Auth: correctness proofs for authentication protocols;
  2107 
  2108 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2109 examples on HOL/Auth);
  2110 
  2111 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2112 the rewriter and classical reasoner simultaneously;
  2113 
  2114 * function uresult no longer returns theorems in "standard" format;
  2115 regain previous version by: val uresult = standard o uresult;
  2116 
  2117 
  2118 
  2119 New in Isabelle94-6
  2120 -------------------
  2121 
  2122 * oracles -- these establish an interface between Isabelle and trusted
  2123 external reasoners, which may deliver results as theorems;
  2124 
  2125 * proof objects (in particular record all uses of oracles);
  2126 
  2127 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2128 
  2129 * "constdefs" section in theory files;
  2130 
  2131 * "primrec" section (HOL) no longer requires names;
  2132 
  2133 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2134 
  2135 
  2136 
  2137 New in Isabelle94-5
  2138 -------------------
  2139 
  2140 * reduced space requirements;
  2141 
  2142 * automatic HTML generation from theories;
  2143 
  2144 * theory files no longer require "..." (quotes) around most types;
  2145 
  2146 * new examples, including two proofs of the Church-Rosser theorem;
  2147 
  2148 * non-curried (1994) version of HOL is no longer distributed;
  2149 
  2150 
  2151 
  2152 New in Isabelle94-4
  2153 -------------------
  2154 
  2155 * greatly reduced space requirements;
  2156 
  2157 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2158 
  2159 * searchable theorem database (see the section "Retrieving theorems" on
  2160 page 8 of the Reference Manual);
  2161 
  2162 * new examples, including Grabczewski's monumental case study of the
  2163 Axiom of Choice;
  2164 
  2165 * The previous version of HOL renamed to Old_HOL;
  2166 
  2167 * The new version of HOL (previously called CHOL) uses a curried syntax
  2168 for functions.  Application looks like f a b instead of f(a,b);
  2169 
  2170 * Mutually recursive inductive definitions finally work in HOL;
  2171 
  2172 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2173 translates to the operator "split";
  2174 
  2175 
  2176 
  2177 New in Isabelle94-3
  2178 -------------------
  2179 
  2180 * new infix operator, addss, allowing the classical reasoner to
  2181 perform simplification at each step of its search.  Example:
  2182         fast_tac (cs addss ss)
  2183 
  2184 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2185 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2186 look like (a,b) instead of <a,b>;
  2187 
  2188 * PLEASE NOTE: CHOL will eventually replace HOL!
  2189 
  2190 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2191 It translates to the operator "split".  A new theory of integers is available;
  2192 
  2193 * In ZF, integer numerals now denote two's-complement binary integers.
  2194 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2195 
  2196 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2197 of the Axiom of Choice;
  2198 
  2199 
  2200 
  2201 New in Isabelle94-2
  2202 -------------------
  2203 
  2204 * Significantly faster resolution;
  2205 
  2206 * the different sections in a .thy file can now be mixed and repeated
  2207 freely;
  2208 
  2209 * Database of theorems for FOL, HOL and ZF.  New
  2210 commands including qed, qed_goal and bind_thm store theorems in the database.
  2211 
  2212 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2213 a given theory (thms_of), or find out what theory a theorem was proved in
  2214 (theory_of_thm);
  2215 
  2216 * Bugs fixed in the inductive definition and datatype packages;
  2217 
  2218 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2219 and HOL_dup_cs obsolete;
  2220 
  2221 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2222 have been removed;
  2223 
  2224 * Simpler definition of function space in ZF;
  2225 
  2226 * new results about cardinal and ordinal arithmetic in ZF;
  2227 
  2228 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2229 types;
  2230 
  2231 
  2232 $Id$