NEWS
author paulson
Thu Jul 04 16:59:54 2002 +0200 (2002-07-04)
changeset 13298 b4f370679c65
parent 13284 20c818c966e6
child 13344 c8eb3fbf4c0c
permissions -rw-r--r--
Constructible: some separation axioms
     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); an
    13 optional limit for the number of printed facts may be given (the
    14 default is 40);
    15 
    16 
    17 *** HOL ***
    18 
    19 * arith(_tac) does now know about div k and mod k where k is a numeral of
    20   type nat. It can solve simple goals like "0 < n ==> n div 2 < (n::nat)"
    21   but fails if divisibility plays a role like in
    22   "n div 2 + (n+1) div 2 = (n::nat)".
    23 * simp's arithmetic capabilities have been enhanced a bit:
    24   it now takes ~= in premises into account (by performing a case split).
    25 
    26 
    27 
    28 New in Isabelle2002 (March 2002)
    29 --------------------------------
    30 
    31 *** Document preparation ***
    32 
    33 * greatly simplified document preparation setup, including more
    34 graceful interpretation of isatool usedir -i/-d/-D options, and more
    35 instructive isatool mkdir; users should basically be able to get
    36 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    37 users may run a separate document processing stage manually like this:
    38 "isatool usedir -D output HOL Test && isatool document Test/output";
    39 
    40 * theory dependency graph may now be incorporated into documents;
    41 isatool usedir -g true will produce session_graph.eps/.pdf for use
    42 with \includegraphics of LaTeX;
    43 
    44 * proper spacing of consecutive markup elements, especially text
    45 blocks after section headings;
    46 
    47 * support bold style (for single symbols only), input syntax is like
    48 this: "\<^bold>\<alpha>" or "\<^bold>A";
    49 
    50 * \<bullet> is now output as bold \cdot by default, which looks much
    51 better in printed text;
    52 
    53 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    54 note that these symbols are currently unavailable in Proof General /
    55 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
    56 
    57 * isatool latex no longer depends on changed TEXINPUTS, instead
    58 isatool document copies the Isabelle style files to the target
    59 location;
    60 
    61 
    62 *** Isar ***
    63 
    64 * Pure/Provers: improved proof by cases and induction;
    65   - 'case' command admits impromptu naming of parameters (such as
    66     "case (Suc n)");
    67   - 'induct' method divinates rule instantiation from the inductive
    68     claim; no longer requires excessive ?P bindings for proper
    69     instantiation of cases;
    70   - 'induct' method properly enumerates all possibilities of set/type
    71     rules; as a consequence facts may be also passed through *type*
    72     rules without further ado;
    73   - 'induct' method now derives symbolic cases from the *rulified*
    74     rule (before it used to rulify cases stemming from the internal
    75     atomized version); this means that the context of a non-atomic
    76     statement becomes is included in the hypothesis, avoiding the
    77     slightly cumbersome show "PROP ?case" form;
    78   - 'induct' may now use elim-style induction rules without chaining
    79     facts, using ``missing'' premises from the goal state; this allows
    80     rules stemming from inductive sets to be applied in unstructured
    81     scripts, while still benefitting from proper handling of non-atomic
    82     statements; NB: major inductive premises need to be put first, all
    83     the rest of the goal is passed through the induction;
    84   - 'induct' proper support for mutual induction involving non-atomic
    85     rule statements (uses the new concept of simultaneous goals, see
    86     below);
    87   - append all possible rule selections, but only use the first
    88     success (no backtracking);
    89   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    90   - undeclared rule case names default to numbers 1, 2, 3, ...;
    91   - added 'print_induct_rules' (covered by help item in recent Proof
    92     General versions);
    93   - moved induct/cases attributes to Pure, methods to Provers;
    94   - generic method setup instantiated for FOL and HOL;
    95 
    96 * Pure: support multiple simultaneous goal statements, for example
    97 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    98 meta-level mechanism, this acts as if several individual goals had
    99 been stated separately; in particular common proof methods need to be
   100 repeated in order to cover all claims; note that a single elimination
   101 step is *not* sufficient to establish the two conjunctions, so this
   102 fails:
   103 
   104   assume "A & B" then have A and B ..   (*".." fails*)
   105 
   106 better use "obtain" in situations as above; alternative refer to
   107 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   108 
   109 * Pure: proper integration with ``locales''; unlike the original
   110 version by Florian Kammüller, Isar locales package high-level proof
   111 contexts rather than raw logical ones (e.g. we admit to include
   112 attributes everywhere); operations on locales include merge and
   113 rename; support for implicit arguments (``structures''); simultaneous
   114 type-inference over imports and text; see also HOL/ex/Locales.thy for
   115 some examples;
   116 
   117 * Pure: the following commands have been ``localized'', supporting a
   118 target locale specification "(in name)": 'lemma', 'theorem',
   119 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   120 stored both within the locale and at the theory level (exported and
   121 qualified by the locale name);
   122 
   123 * Pure: theory goals may now be specified in ``long'' form, with
   124 ad-hoc contexts consisting of arbitrary locale elements. for example
   125 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   126 definitions may be given, too); the result is a meta-level rule with
   127 the context elements being discharged in the obvious way;
   128 
   129 * Pure: new proof command 'using' allows to augment currently used
   130 facts after a goal statement ('using' is syntactically analogous to
   131 'apply', but acts on the goal's facts only); this allows chained facts
   132 to be separated into parts given before and after a claim, as in
   133 ``from a and b have C using d and e <proof>'';
   134 
   135 * Pure: renamed "antecedent" case to "rule_context";
   136 
   137 * Pure: new 'judgment' command records explicit information about the
   138 object-logic embedding (used by several tools internally); no longer
   139 use hard-wired "Trueprop";
   140 
   141 * Pure: added 'corollary' command;
   142 
   143 * Pure: fixed 'token_translation' command;
   144 
   145 * Pure: removed obsolete 'exported' attribute;
   146 
   147 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   148 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   149 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   150 
   151 * Pure: method 'atomize' presents local goal premises as object-level
   152 statements (atomic meta-level propositions); setup controlled via
   153 rewrite rules declarations of 'atomize' attribute; example
   154 application: 'induct' method with proper rule statements in improper
   155 proof *scripts*;
   156 
   157 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   158 now consider the syntactic context of assumptions, giving a better
   159 chance to get type-inference of the arguments right (this is
   160 especially important for locales);
   161 
   162 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   163 mode;
   164 
   165 * Pure/obtain: the formal conclusion "thesis", being marked as
   166 ``internal'', may no longer be reference directly in the text;
   167 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   168 situations;
   169 
   170 * Pure: generic 'sym' attribute which declares a rule both as pure
   171 'elim?' and for the 'symmetric' operation;
   172 
   173 * Pure: marginal comments ``--'' may now occur just anywhere in the
   174 text; the fixed correlation with particular command syntax has been
   175 discontinued;
   176 
   177 * Pure: new method 'rules' is particularly well-suited for proof
   178 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   179 but often produces more compact proof terms with less detours;
   180 
   181 * Pure/Provers/classical: simplified integration with pure rule
   182 attributes and methods; the classical "intro?/elim?/dest?"
   183 declarations coincide with the pure ones; the "rule" method no longer
   184 includes classically swapped intros; "intro" and "elim" methods no
   185 longer pick rules from the context; also got rid of ML declarations
   186 AddXIs/AddXEs/AddXDs; all of this has some potential for
   187 INCOMPATIBILITY;
   188 
   189 * Provers/classical: attribute 'swapped' produces classical inversions
   190 of introduction rules;
   191 
   192 * Provers/simplifier: 'simplified' attribute may refer to explicit
   193 rules instead of full simplifier context; 'iff' attribute handles
   194 conditional rules;
   195 
   196 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   197 
   198 * HOL: 'recdef' now fails on unfinished automated proofs, use
   199 "(permissive)" option to recover old behavior;
   200 
   201 * HOL: 'inductive' no longer features separate (collective) attributes
   202 for 'intros' (was found too confusing);
   203 
   204 * HOL: properly declared induction rules less_induct and
   205 wf_induct_rule;
   206 
   207 
   208 *** HOL ***
   209 
   210 * HOL: moved over to sane numeral syntax; the new policy is as
   211 follows:
   212 
   213   - 0 and 1 are polymorphic constants, which are defined on any
   214   numeric type (nat, int, real etc.);
   215 
   216   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   217   binary representation internally;
   218 
   219   - type nat has special constructor Suc, and generally prefers Suc 0
   220   over 1::nat and Suc (Suc 0) over 2::nat;
   221 
   222 This change may cause significant problems of INCOMPATIBILITY; here
   223 are some hints on converting existing sources:
   224 
   225   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   226   entities, so expressions involving "-" (unary or binary minus) need
   227   to be spaced properly;
   228 
   229   - existing occurrences of "1" may need to be constraint "1::nat" or
   230   even replaced by Suc 0; similar for old "2";
   231 
   232   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   233 
   234   - remove all special provisions on numerals in proofs;
   235 
   236 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   237 representation (depends on bin_arith_simps in the default context);
   238 
   239 * HOL: symbolic syntax for x^2 (numeral 2);
   240 
   241 * HOL: the class of all HOL types is now called "type" rather than
   242 "term"; INCOMPATIBILITY, need to adapt references to this type class
   243 in axclass/classes, instance/arities, and (usually rare) occurrences
   244 in typings (of consts etc.); internally the class is called
   245 "HOL.type", ML programs should refer to HOLogic.typeS;
   246 
   247 * HOL/record package improvements:
   248   - new derived operations "fields" to build a partial record section,
   249     "extend" to promote a fixed record to a record scheme, and
   250     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   251     declared as simp by default;
   252   - shared operations ("more", "fields", etc.) now need to be always
   253     qualified) --- potential INCOMPATIBILITY;
   254   - removed "make_scheme" operations (use "make" with "extend") --
   255     INCOMPATIBILITY;
   256   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   257   - provides cases/induct rules for use with corresponding Isar
   258     methods (for concrete records, record schemes, concrete more
   259     parts, and schematic more parts -- in that order);
   260   - internal definitions directly based on a light-weight abstract
   261     theory of product types over typedef rather than datatype;
   262 
   263 * HOL: generic code generator for generating executable ML code from
   264 specifications; specific support for HOL constructs such as inductive
   265 datatypes and sets, as well as recursive functions; can be invoked
   266 via 'generate_code' theory section;
   267 
   268 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   269 
   270 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   271 (beware of argument permutation!);
   272 
   273 * HOL: linorder_less_split superseded by linorder_cases;
   274 
   275 * HOL/List: "nodups" renamed to "distinct";
   276 
   277 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   278 to peripheral theory "Hilbert_Choice";
   279 
   280 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   281 in this (rare) case use:
   282 
   283   delSWrapper "split_all_tac"
   284   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   285 
   286 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   287 MAY FAIL;
   288 
   289 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   290 Isabelle's type classes, ^ on functions and relations has too general
   291 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   292 necessary to attach explicit type constraints;
   293 
   294 * HOL/Relation: the prefix name of the infix "O" has been changed from
   295 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   296 renamed accordingly (eg "compI" -> "rel_compI").
   297 
   298 * HOL: syntax translations now work properly with numerals and records
   299 expressions;
   300 
   301 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   302 of "lam" -- INCOMPATIBILITY;
   303 
   304 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   305 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   306 renamed "Product_Type.unit";
   307 
   308 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   309 
   310 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   311 the "cases" method);
   312 
   313 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   314 Florian Kammüller);
   315 
   316 * HOL/IMP: updated and converted to new-style theory format; several
   317 parts turned into readable document, with proper Isar proof texts and
   318 some explanations (by Gerwin Klein);
   319 
   320 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   321 
   322 * HOL-Hyperreal is now a logic image;
   323 
   324 
   325 *** HOLCF ***
   326 
   327 * Isar: consts/constdefs supports mixfix syntax for continuous
   328 operations;
   329 
   330 * Isar: domain package adapted to new-style theory format, e.g. see
   331 HOLCF/ex/Dnat.thy;
   332 
   333 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   334 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   335 lift.induct_tac, always use UU instead of Undef;
   336 
   337 * HOLCF/IMP: updated and converted to new-style theory;
   338 
   339 
   340 *** ZF ***
   341 
   342 * Isar: proper integration of logic-specific tools and packages,
   343 including theory commands '(co)inductive', '(co)datatype',
   344 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   345 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   346 
   347 * theory Main no longer includes AC; for the Axiom of Choice, base
   348 your theory on Main_ZFC;
   349 
   350 * the integer library now covers quotients and remainders, with many
   351 laws relating division to addition, multiplication, etc.;
   352 
   353 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   354 typeless version of the formalism;
   355 
   356 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   357 format;
   358 
   359 * ZF/Induct: new directory for examples of inductive definitions,
   360 including theory Multiset for multiset orderings; converted to
   361 new-style theory format;
   362 
   363 * ZF: many new theorems about lists, ordinals, etc.;
   364 
   365 
   366 *** General ***
   367 
   368 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   369 variable proof controls level of detail: 0 = no proofs (only oracle
   370 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   371 also ref manual for further ML interfaces;
   372 
   373 * Pure/axclass: removed obsolete ML interface
   374 goal_subclass/goal_arity;
   375 
   376 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   377 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   378 separate tokens, so expressions involving minus need to be spaced
   379 properly;
   380 
   381 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   382 rather than "infixl" or "infixr";
   383 
   384 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   385 sort constraint specifications in type inference; e.g. "x::_::foo"
   386 ensures that the type of "x" is of sort "foo" (but not necessarily a
   387 type variable);
   388 
   389 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   390 control output of nested => (types); the default behavior is
   391 "type_brackets";
   392 
   393 * Pure/syntax: builtin parse translation for "_constify" turns valued
   394 tokens into AST constants;
   395 
   396 * Pure/syntax: prefer later declarations of translations and print
   397 translation functions; potential INCOMPATIBILITY: need to reverse
   398 multiple declarations for same syntax element constant;
   399 
   400 * Pure/show_hyps reset by default (in accordance to existing Isar
   401 practice);
   402 
   403 * Provers/classical: renamed addaltern to addafter, addSaltern to
   404 addSafter;
   405 
   406 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   407 as well;
   408 
   409 * system: tested support for MacOS X; should be able to get Isabelle +
   410 Proof General to work in a plain Terminal after installing Poly/ML
   411 (e.g. from the Isabelle distribution area) and GNU bash alone
   412 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   413 support requires further installations, e.g. from
   414 http://fink.sourceforge.net/);
   415 
   416 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   417 
   418 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   419 of 40 MB), cf. ML_OPTIONS;
   420 
   421 * system: Proof General keywords specification is now part of the
   422 Isabelle distribution (see etc/isar-keywords.el);
   423 
   424 * system: support for persistent Proof General sessions (refrain from
   425 outdating all loaded theories on startup); user may create writable
   426 logic images like this: ``isabelle -q HOL Test'';
   427 
   428 * system: smart selection of Isabelle process versus Isabelle
   429 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   430 run both "isabelle" and "Isabelle" even if file names are badly
   431 damaged (executable inspects the case of the first letter of its own
   432 name); added separate "isabelle-process" and "isabelle-interface";
   433 
   434 * system: refrain from any attempt at filtering input streams; no
   435 longer support ``8bit'' encoding of old isabelle font, instead proper
   436 iso-latin characters may now be used; the related isatools
   437 "symbolinput" and "nonascii" have disappeared as well;
   438 
   439 * system: removed old "xterm" interface (the print modes "xterm" and
   440 "xterm_color" are still available for direct use in a suitable
   441 terminal);
   442 
   443 
   444 
   445 New in Isabelle99-2 (February 2001)
   446 -----------------------------------
   447 
   448 *** Overview of INCOMPATIBILITIES ***
   449 
   450 * HOL: please note that theories in the Library and elsewhere often use the
   451 new-style (Isar) format; to refer to their theorems in an ML script you must
   452 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   453 
   454 * HOL: inductive package no longer splits induction rule aggressively,
   455 but only as far as specified by the introductions given; the old
   456 format may be recovered via ML function complete_split_rule or attribute
   457 'split_rule (complete)';
   458 
   459 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   460 gfp_Tarski to gfp_unfold;
   461 
   462 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   463 
   464 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   465 relation); infix "^^" has been renamed "``"; infix "``" has been
   466 renamed "`"; "univalent" has been renamed "single_valued";
   467 
   468 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   469 operation;
   470 
   471 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   472 
   473 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   474 
   475 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   476 consequence, it is no longer monotonic wrt. the local goal context
   477 (which is now passed through the inductive cases);
   478 
   479 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   480 \<gg> to \<ggreater>;
   481 
   482 
   483 *** Document preparation ***
   484 
   485 * \isabellestyle{NAME} selects version of Isabelle output (currently
   486 available: are "it" for near math-mode best-style output, "sl" for
   487 slanted text style, and "tt" for plain type-writer; if no
   488 \isabellestyle command is given, output is according to slanted
   489 type-writer);
   490 
   491 * support sub/super scripts (for single symbols only), input syntax is
   492 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   493 
   494 * some more standard symbols; see Appendix A of the system manual for
   495 the complete list of symbols defined in isabellesym.sty;
   496 
   497 * improved isabelle style files; more abstract symbol implementation
   498 (should now use \isamath{...} and \isatext{...} in custom symbol
   499 definitions);
   500 
   501 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   502 state; Note that presentation of goal states does not conform to
   503 actual human-readable proof documents.  Please do not include goal
   504 states into document output unless you really know what you are doing!
   505 
   506 * proper indentation of antiquoted output with proportional LaTeX
   507 fonts;
   508 
   509 * no_document ML operator temporarily disables LaTeX document
   510 generation;
   511 
   512 * isatool unsymbolize tunes sources for plain ASCII communication;
   513 
   514 
   515 *** Isar ***
   516 
   517 * Pure: Isar now suffers initial goal statements to contain unbound
   518 schematic variables (this does not conform to actual readable proof
   519 documents, due to unpredictable outcome and non-compositional proof
   520 checking); users who know what they are doing may use schematic goals
   521 for Prolog-style synthesis of proven results;
   522 
   523 * Pure: assumption method (an implicit finishing) now handles actual
   524 rules as well;
   525 
   526 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   527 initial goal, declare "that" only as Pure intro (only for single
   528 steps); the "that" rule assumption may now be involved in implicit
   529 finishing, thus ".." becomes a feasible for trivial obtains;
   530 
   531 * Pure: default proof step now includes 'intro_classes'; thus trivial
   532 instance proofs may be performed by "..";
   533 
   534 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   535 statements as well;
   536 
   537 * Pure: more robust selection of calculational rules;
   538 
   539 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   540 rule (as well as the assumption rule);
   541 
   542 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   543 lemmas, using the graph browser tool;
   544 
   545 * Pure: predict failure of "show" in interactive mode;
   546 
   547 * Pure: 'thms_containing' now takes actual terms as arguments;
   548 
   549 * HOL: improved method 'induct' --- now handles non-atomic goals
   550 (potential INCOMPATIBILITY); tuned error handling;
   551 
   552 * HOL: cases and induct rules now provide explicit hints about the
   553 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   554 any remaining facts are inserted into the goal verbatim;
   555 
   556 * HOL: local contexts (aka cases) may now contain term bindings as
   557 well; the 'cases' and 'induct' methods new provide a ?case binding for
   558 the result to be shown in each case;
   559 
   560 * HOL: added 'recdef_tc' command;
   561 
   562 * isatool convert assists in eliminating legacy ML scripts;
   563 
   564 
   565 *** HOL ***
   566 
   567 * HOL/Library: a collection of generic theories to be used together
   568 with main HOL; the theory loader path already includes this directory
   569 by default; the following existing theories have been moved here:
   570 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   571 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   572 
   573 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   574 modelling and verification task performed in Isabelle/HOL +
   575 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   576 
   577 * HOL/Algebra: special summation operator SUM no longer exists, it has
   578 been replaced by setsum; infix 'assoc' now has priority 50 (like
   579 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   580 'domain', this makes the theory consistent with mathematical
   581 literature;
   582 
   583 * HOL basics: added overloaded operations "inverse" and "divide"
   584 (infix "/"), syntax for generic "abs" operation, generic summation
   585 operator \<Sum>;
   586 
   587 * HOL/typedef: simplified package, provide more useful rules (see also
   588 HOL/subset.thy);
   589 
   590 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   591 now expressed as a proper nested rule (old-style tactic scripts may
   592 require atomize_strip_tac to cope with non-atomic premises);
   593 
   594 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   595 to "split_conv" (old name still available for compatibility);
   596 
   597 * HOL: improved concrete syntax for strings (e.g. allows translation
   598 rules with string literals);
   599 
   600 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   601  and Fleuriot's mechanization of analysis, including the transcendental
   602  functions for the reals;
   603 
   604 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   605 
   606 
   607 *** CTT ***
   608 
   609 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   610 "lam" is displayed as TWO lambda-symbols
   611 
   612 * CTT: theory Main now available, containing everything (that is, Bool
   613 and Arith);
   614 
   615 
   616 *** General ***
   617 
   618 * Pure: the Simplifier has been implemented properly as a derived rule
   619 outside of the actual kernel (at last!); the overall performance
   620 penalty in practical applications is about 50%, while reliability of
   621 the Isabelle inference kernel has been greatly improved;
   622 
   623 * print modes "brackets" and "no_brackets" control output of nested =>
   624 (types) and ==> (props); the default behaviour is "brackets";
   625 
   626 * Provers: fast_tac (and friends) now handle actual object-logic rules
   627 as assumptions as well;
   628 
   629 * system: support Poly/ML 4.0;
   630 
   631 * system: isatool install handles KDE version 1 or 2;
   632 
   633 
   634 
   635 New in Isabelle99-1 (October 2000)
   636 ----------------------------------
   637 
   638 *** Overview of INCOMPATIBILITIES ***
   639 
   640 * HOL: simplification of natural numbers is much changed; to partly
   641 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   642 issue the following ML commands:
   643 
   644   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   645   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   646 
   647 * HOL: simplification no longer dives into case-expressions; this is
   648 controlled by "t.weak_case_cong" for each datatype t;
   649 
   650 * HOL: nat_less_induct renamed to less_induct;
   651 
   652 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   653 fixsome to patch .thy and .ML sources automatically;
   654 
   655   select_equality  -> some_equality
   656   select_eq_Ex     -> some_eq_ex
   657   selectI2EX       -> someI2_ex
   658   selectI2         -> someI2
   659   selectI          -> someI
   660   select1_equality -> some1_equality
   661   Eps_sym_eq       -> some_sym_eq_trivial
   662   Eps_eq           -> some_eq_trivial
   663 
   664 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   665 
   666 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   667 instead);
   668 
   669 * HOL: the recursion equations generated by 'recdef' are now called
   670 f.simps instead of f.rules;
   671 
   672 * HOL: qed_spec_mp now also handles bounded ALL as well;
   673 
   674 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   675 sometimes be needed;
   676 
   677 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   678 
   679 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   680 
   681 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   682 product is now "<*>" instead of "Times"; the lexicographic product is
   683 now "<*lex*>" instead of "**";
   684 
   685 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   686 of main HOL, but was unused); better use HOL's datatype package;
   687 
   688 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   689 the old syntax may be recovered as follows:
   690 
   691   syntax (symbols)
   692     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   693       (infixl "\\<oplus>" 100)
   694 
   695 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   696 
   697 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   698 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   699 internally;
   700 
   701 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   702 changed from A/r to A//r;
   703 
   704 * ZF: new treatment of arithmetic (nat & int) may break some old
   705 proofs;
   706 
   707 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   708 rulify -> rule_format, elimify -> elim_format, ...);
   709 
   710 * Isar/Provers: intro/elim/dest attributes changed; renamed
   711 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   712 should have to change intro!! to intro? only); replaced "delrule" by
   713 "rule del";
   714 
   715 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   716 
   717 * Provers: strengthened force_tac by using new first_best_tac;
   718 
   719 * LaTeX document preparation: several changes of isabelle.sty (see
   720 lib/texinputs);
   721 
   722 
   723 *** Document preparation ***
   724 
   725 * formal comments (text blocks etc.) in new-style theories may now
   726 contain antiquotations of thm/prop/term/typ/text to be presented
   727 according to latex print mode; concrete syntax is like this:
   728 @{term[show_types] "f(x) = a + x"};
   729 
   730 * isatool mkdir provides easy setup of Isabelle session directories,
   731 including proper document sources;
   732 
   733 * generated LaTeX sources are now deleted after successful run
   734 (isatool document -c); may retain a copy somewhere else via -D option
   735 of isatool usedir;
   736 
   737 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   738 style files, achieving self-contained LaTeX sources and simplifying
   739 LaTeX debugging;
   740 
   741 * old-style theories now produce (crude) LaTeX output as well;
   742 
   743 * browser info session directories are now self-contained (may be put
   744 on WWW server seperately); improved graphs of nested sessions; removed
   745 graph for 'all sessions';
   746 
   747 * several improvements in isabelle style files; \isabellestyle{it}
   748 produces fake math mode output; \isamarkupheader is now \section by
   749 default; see lib/texinputs/isabelle.sty etc.;
   750 
   751 
   752 *** Isar ***
   753 
   754 * Isar/Pure: local results and corresponding term bindings are now
   755 subject to Hindley-Milner polymorphism (similar to ML); this
   756 accommodates incremental type-inference very nicely;
   757 
   758 * Isar/Pure: new derived language element 'obtain' supports
   759 generalized existence reasoning;
   760 
   761 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   762 support accumulation of results, without applying any rules yet;
   763 useful to collect intermediate results without explicit name
   764 references, and for use with transitivity rules with more than 2
   765 premises;
   766 
   767 * Isar/Pure: scalable support for case-analysis type proofs: new
   768 'case' language element refers to local contexts symbolically, as
   769 produced by certain proof methods; internally, case names are attached
   770 to theorems as "tags";
   771 
   772 * Isar/Pure: theory command 'hide' removes declarations from
   773 class/type/const name spaces;
   774 
   775 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   776 indicate potential overloading;
   777 
   778 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   779 
   780 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   781 "{a,b,c}" instead of {a,b,c};
   782 
   783 * Isar/Pure now provides its own version of intro/elim/dest
   784 attributes; useful for building new logics, but beware of confusion
   785 with the version in Provers/classical;
   786 
   787 * Isar/Pure: the local context of (non-atomic) goals is provided via
   788 case name 'antecedent';
   789 
   790 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   791 to the current context is now done automatically);
   792 
   793 * Isar/Pure: theory command 'method_setup' provides a simple interface
   794 for definining proof methods in ML;
   795 
   796 * Isar/Provers: intro/elim/dest attributes changed; renamed
   797 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   798 most cases, one should have to change intro!! to intro? only);
   799 replaced "delrule" by "rule del";
   800 
   801 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   802 'symmetric' attribute (the latter supercedes [RS sym]);
   803 
   804 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   805 method modifier); 'simp' method: 'only:' modifier removes loopers as
   806 well (including splits);
   807 
   808 * Isar/Provers: Simplifier and Classical methods now support all kind
   809 of modifiers used in the past, including 'cong', 'iff', etc.
   810 
   811 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   812 of Simplifier and Classical reasoner);
   813 
   814 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   815 now support named cases; major packages (inductive, datatype, primrec,
   816 recdef) support case names and properly name parameters;
   817 
   818 * Isar/HOL: new transitivity rules for substitution in inequalities --
   819 monotonicity conditions are extracted to be proven at end of
   820 calculations;
   821 
   822 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   823 method anyway;
   824 
   825 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   826 split_if split_if_asm; datatype package provides theorems foo.splits =
   827 foo.split foo.split_asm for each datatype;
   828 
   829 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   830 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   831 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   832 use "(cases (simplified))" method in proper proof texts);
   833 
   834 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   835 
   836 * Isar: names of theorems etc. may be natural numbers as well;
   837 
   838 * Isar: 'pr' command: optional arguments for goals_limit and
   839 ProofContext.prems_limit; no longer prints theory contexts, but only
   840 proof states;
   841 
   842 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   843 additional print modes to be specified; e.g. "pr(latex)" will print
   844 proof state according to the Isabelle LaTeX style;
   845 
   846 * Isar: improved support for emulating tactic scripts, including proof
   847 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   848 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   849 (for HOL datatypes);
   850 
   851 * Isar: simplified (more robust) goal selection of proof methods: 1st
   852 goal, all goals, or explicit goal specifier (tactic emulation); thus
   853 'proof method scripts' have to be in depth-first order;
   854 
   855 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   856 
   857 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   858 should instead use individual commands for printing items
   859 (print_commands, print_methods etc.);
   860 
   861 * Isar: added 'nothing' --- the empty list of theorems;
   862 
   863 
   864 *** HOL ***
   865 
   866 * HOL/MicroJava: formalization of a fragment of Java, together with a
   867 corresponding virtual machine and a specification of its bytecode
   868 verifier and a lightweight bytecode verifier, including proofs of
   869 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   870 Cornelia Pusch (see also the homepage of project Bali at
   871 http://isabelle.in.tum.de/Bali/);
   872 
   873 * HOL/Algebra: new theory of rings and univariate polynomials, by
   874 Clemens Ballarin;
   875 
   876 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   877 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   878 Rasmussen;
   879 
   880 * HOL/Lattice: fundamental concepts of lattice theory and order
   881 structures, including duals, properties of bounds versus algebraic
   882 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   883 Theorem for complete lattices etc.; may also serve as a demonstration
   884 for abstract algebraic reasoning using axiomatic type classes, and
   885 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   886 
   887 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   888 von Oheimb;
   889 
   890 * HOL/IMPP: extension of IMP with local variables and mutually
   891 recursive procedures, by David von Oheimb;
   892 
   893 * HOL/Lambda: converted into new-style theory and document;
   894 
   895 * HOL/ex/Multiquote: example of multiple nested quotations and
   896 anti-quotations -- basically a generalized version of de-Bruijn
   897 representation; very useful in avoiding lifting of operations;
   898 
   899 * HOL/record: added general record equality rule to simpset; fixed
   900 select-update simplification procedure to handle extended records as
   901 well; admit "r" as field name;
   902 
   903 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   904 other numeric types and also as the identity of groups, rings, etc.;
   905 
   906 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   907 Types nat and int belong to this axclass;
   908 
   909 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   910    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   911    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   912   two terms #m*u and #n*u are replaced by #(m+n)*u
   913     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   914   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   915     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   916 
   917 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   918 powerful prover for predicate logic but knows nothing of clasets; see
   919 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   920 
   921 * HOL: new version of "case_tac" subsumes both boolean case split and
   922 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   923 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   924 
   925 * HOL: simplification no longer dives into case-expressions: only the
   926 selector expression is simplified, but not the remaining arms; to
   927 enable full simplification of case-expressions for datatype t, you may
   928 remove t.weak_case_cong from the simpset, either globally (Delcongs
   929 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   930 
   931 * HOL/recdef: the recursion equations generated by 'recdef' for
   932 function 'f' are now called f.simps instead of f.rules; if all
   933 termination conditions are proved automatically, these simplification
   934 rules are added to the simpset, as in primrec; rules may be named
   935 individually as well, resulting in a separate list of theorems for
   936 each equation;
   937 
   938 * HOL/While is a new theory that provides a while-combinator. It
   939 permits the definition of tail-recursive functions without the
   940 provision of a termination measure. The latter is necessary once the
   941 invariant proof rule for while is applied.
   942 
   943 * HOL: new (overloaded) notation for the set of elements below/above
   944 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   945 
   946 * HOL: theorems impI, allI, ballI bound as "strip";
   947 
   948 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   949 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   950 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   951 
   952 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   953 
   954 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   955 main HOL, but was unused);
   956 
   957 * HOL: fewer consts declared as global (e.g. have to refer to
   958 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   959 
   960 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   961 in case of overlap with user translations (e.g. judgements over
   962 tuples); (note that the underlying logical represenation is still
   963 bogus);
   964 
   965 
   966 *** ZF ***
   967 
   968 * ZF: simplification automatically cancels common terms in arithmetic
   969 expressions over nat and int;
   970 
   971 * ZF: new treatment of nat to minimize type-checking: all operators
   972 coerce their operands to a natural number using the function natify,
   973 making the algebraic laws unconditional;
   974 
   975 * ZF: as above, for int: operators coerce their operands to an integer
   976 using the function intify;
   977 
   978 * ZF: the integer library now contains many of the usual laws for the
   979 orderings, including $<=, and monotonicity laws for $+ and $*;
   980 
   981 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   982 simplification;
   983 
   984 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   985 to the simplifier and classical reasoner simultaneously;
   986 
   987 
   988 *** General ***
   989 
   990 * Provers: blast_tac now handles actual object-logic rules as
   991 assumptions; note that auto_tac uses blast_tac internally as well;
   992 
   993 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   994 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   995 
   996 * Provers: delrules now handles destruct rules as well (no longer need
   997 explicit make_elim);
   998 
   999 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1000   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1001 use instead the strong form,
  1002   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1003 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1004 from destruct-rules;
  1005 
  1006 * Provers: Simplifier.easy_setup provides a fast path to basic
  1007 Simplifier setup for new object-logics;
  1008 
  1009 * Pure: AST translation rules no longer require constant head on LHS;
  1010 
  1011 * Pure: improved name spaces: ambiguous output is qualified; support
  1012 for hiding of names;
  1013 
  1014 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1015 XSYMBOL_HOME; no longer need to do manual configuration in most
  1016 situations;
  1017 
  1018 * system: compression of ML heaps images may now be controlled via -c
  1019 option of isabelle and isatool usedir (currently only observed by
  1020 Poly/ML);
  1021 
  1022 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1023 useful for remote X11);
  1024 
  1025 * system: provide TAGS file for Isabelle sources;
  1026 
  1027 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1028 order;
  1029 
  1030 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1031 timing flag supersedes proof_timing and Toplevel.trace;
  1032 
  1033 * ML: new combinators |>> and |>>> for incremental transformations
  1034 with secondary results (e.g. certain theory extensions):
  1035 
  1036 * ML: PureThy.add_defs gets additional argument to indicate potential
  1037 overloading (usually false);
  1038 
  1039 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1040 results;
  1041 
  1042 
  1043 
  1044 New in Isabelle99 (October 1999)
  1045 --------------------------------
  1046 
  1047 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1048 
  1049 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1050 are no longer simplified.  (This allows the simplifier to unfold recursive
  1051 functional programs.)  To restore the old behaviour, declare
  1052 
  1053     Delcongs [if_weak_cong];
  1054 
  1055 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1056 complement;
  1057 
  1058 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1059 
  1060 * HOL/datatype: mutual_induct_tac no longer exists --
  1061   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1062 
  1063 * HOL/typedef: fixed type inference for representing set; type
  1064 arguments now have to occur explicitly on the rhs as type constraints;
  1065 
  1066 * ZF: The con_defs part of an inductive definition may no longer refer
  1067 to constants declared in the same theory;
  1068 
  1069 * HOL, ZF: the function mk_cases, generated by the inductive
  1070 definition package, has lost an argument.  To simplify its result, it
  1071 uses the default simpset instead of a supplied list of theorems.
  1072 
  1073 * HOL/List: the constructors of type list are now Nil and Cons;
  1074 
  1075 * Simplifier: the type of the infix ML functions
  1076         setSSolver addSSolver setSolver addSolver
  1077 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1078 for packaging solvers. A solver is created via
  1079         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1080 where the string argument is only a comment.
  1081 
  1082 
  1083 *** Proof tools ***
  1084 
  1085 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1086 decision procedure for linear arithmetic. Currently it is used for
  1087 types `nat', `int', and `real' in HOL (see below); it can, should and
  1088 will be instantiated for other types and logics as well.
  1089 
  1090 * The simplifier now accepts rewrite rules with flexible heads, eg
  1091      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1092   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1093   matching.
  1094 
  1095 
  1096 *** General ***
  1097 
  1098 * New Isabelle/Isar subsystem provides an alternative to traditional
  1099 tactical theorem proving; together with the ProofGeneral/isar user
  1100 interface it offers an interactive environment for developing human
  1101 readable proof documents (Isar == Intelligible semi-automated
  1102 reasoning); for further information see isatool doc isar-ref,
  1103 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1104 
  1105 * improved and simplified presentation of theories: better HTML markup
  1106 (including colors), graph views in several sizes; isatool usedir now
  1107 provides a proper interface for user theories (via -P option); actual
  1108 document preparation based on (PDF)LaTeX is available as well (for
  1109 new-style theories only); see isatool doc system for more information;
  1110 
  1111 * native support for Proof General, both for classic Isabelle and
  1112 Isabelle/Isar;
  1113 
  1114 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1115 using the graph browser tool;
  1116 
  1117 * Isabelle manuals now also available as PDF;
  1118 
  1119 * theory loader rewritten from scratch (may not be fully
  1120 bug-compatible); old loadpath variable has been replaced by show_path,
  1121 add_path, del_path, reset_path functions; new operations such as
  1122 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1123 isatool doc ref);
  1124 
  1125 * improved isatool install: option -k creates KDE application icon,
  1126 option -p DIR installs standalone binaries;
  1127 
  1128 * added ML_PLATFORM setting (useful for cross-platform installations);
  1129 more robust handling of platform specific ML images for SML/NJ;
  1130 
  1131 * the settings environment is now statically scoped, i.e. it is never
  1132 created again in sub-processes invoked from isabelle, isatool, or
  1133 Isabelle;
  1134 
  1135 * path element specification '~~' refers to '$ISABELLE_HOME';
  1136 
  1137 * in locales, the "assumes" and "defines" parts may be omitted if
  1138 empty;
  1139 
  1140 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1141 long arrows);
  1142 
  1143 * new print_mode "HTML";
  1144 
  1145 * new flag show_tags controls display of tags of theorems (which are
  1146 basically just comments that may be attached by some tools);
  1147 
  1148 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1149 mode and goal output format:
  1150 
  1151 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1152 244c244
  1153 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1154 ---
  1155 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1156 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1157 181c181
  1158 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1159 ---
  1160 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1161 
  1162 * function bind_thms stores lists of theorems (cf. bind_thm);
  1163 
  1164 * new shorthand tactics ftac, eatac, datac, fatac;
  1165 
  1166 * qed (and friends) now accept "" as result name; in that case the
  1167 theorem is not stored, but proper checks and presentation of the
  1168 result still apply;
  1169 
  1170 * theorem database now also indexes constants "Trueprop", "all",
  1171 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1172 
  1173 
  1174 *** HOL ***
  1175 
  1176 ** HOL arithmetic **
  1177 
  1178 * There are now decision procedures for linear arithmetic over nat and
  1179 int:
  1180 
  1181 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1182 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1183 are treated as atomic; subformulae not involving type `nat' or `int'
  1184 are ignored; quantified subformulae are ignored unless they are
  1185 positive universal or negative existential. The tactic has to be
  1186 invoked by hand and can be a little bit slow. In particular, the
  1187 running time is exponential in the number of occurrences of `min' and
  1188 `max', and `-' on `nat'.
  1189 
  1190 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1191 (negated) (in)equalities among the premises and the conclusion into
  1192 account (i.e. no compound formulae) and does not know about `min' and
  1193 `max', and `-' on `nat'. It is fast and is used automatically by the
  1194 simplifier.
  1195 
  1196 NB: At the moment, these decision procedures do not cope with mixed
  1197 nat/int formulae where the two parts interact, such as `m < n ==>
  1198 int(m) < int(n)'.
  1199 
  1200 * HOL/Numeral provides a generic theory of numerals (encoded
  1201 efficiently as bit strings); setup for types nat/int/real is in place;
  1202 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1203 int, existing theories and proof scripts may require a few additional
  1204 type constraints;
  1205 
  1206 * integer division and remainder can now be performed on constant
  1207 arguments;
  1208 
  1209 * many properties of integer multiplication, division and remainder
  1210 are now available;
  1211 
  1212 * An interface to the Stanford Validity Checker (SVC) is available through the
  1213 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1214 are proved automatically.  SVC must be installed separately, and its results
  1215 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1216 invocation of the underlying oracle).  For SVC see
  1217   http://verify.stanford.edu/SVC
  1218 
  1219 * IsaMakefile: the HOL-Real target now builds an actual image;
  1220 
  1221 
  1222 ** HOL misc **
  1223 
  1224 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1225 (in Isabelle/Isar) -- by Gertrud Bauer;
  1226 
  1227 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1228 analysis for assembly languages with subtypes;
  1229 
  1230 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1231 -- avoids syntactic ambiguities and treats state, transition, and
  1232 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1233 changed syntax and (many) tactics;
  1234 
  1235 * HOL/inductive: Now also handles more general introduction rules such
  1236   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1237   theorems are now maintained within the theory (maintained via the
  1238   "mono" attribute);
  1239 
  1240 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1241   (using function types) such as
  1242 
  1243   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1244 
  1245 * HOL/record: record_simproc (part of the default simpset) takes care
  1246 of selectors applied to updated records; record_split_tac is no longer
  1247 part of the default claset; update_defs may now be removed from the
  1248 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1249 
  1250   claset_ref () := claset() addSWrapper record_split_wrapper;
  1251   Delsimprocs [record_simproc]
  1252 
  1253 * HOL/typedef: fixed type inference for representing set; type
  1254 arguments now have to occur explicitly on the rhs as type constraints;
  1255 
  1256 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1257 names rather than an ML expression;
  1258 
  1259 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1260 supplied later.  Program schemes can be defined, such as
  1261     "While B C s = (if B s then While B C (C s) else s)"
  1262 where the well-founded relation can be chosen after B and C have been given.
  1263 
  1264 * HOL/List: the constructors of type list are now Nil and Cons;
  1265 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1266 course, ML tools referring to List.list.op # etc. have to be adapted;
  1267 
  1268 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1269 disabled by default; run isabelle with option -m HOL to get back to
  1270 the original Gordon/HOL-style output;
  1271 
  1272 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1273 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1274 
  1275 * HOL basic syntax simplified (more orthogonal): all variants of
  1276 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1277 Eps operator is provided as well: "SOME x. P[x]";
  1278 
  1279 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1280 
  1281 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1282 thus available for user theories;
  1283 
  1284 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1285 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1286 time;
  1287 
  1288 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1289 several times and then mp;
  1290 
  1291 
  1292 *** LK ***
  1293 
  1294 * the notation <<...>> is now available as a notation for sequences of
  1295 formulas;
  1296 
  1297 * the simplifier is now installed
  1298 
  1299 * the axiom system has been generalized (thanks to Soren Heilmann)
  1300 
  1301 * the classical reasoner now has a default rule database
  1302 
  1303 
  1304 *** ZF ***
  1305 
  1306 * new primrec section allows primitive recursive functions to be given
  1307 directly (as in HOL) over datatypes and the natural numbers;
  1308 
  1309 * new tactics induct_tac and exhaust_tac for induction (or case
  1310 analysis) over datatypes and the natural numbers;
  1311 
  1312 * the datatype declaration of type T now defines the recursor T_rec;
  1313 
  1314 * simplification automatically does freeness reasoning for datatype
  1315 constructors;
  1316 
  1317 * automatic type-inference, with AddTCs command to insert new
  1318 type-checking rules;
  1319 
  1320 * datatype introduction rules are now added as Safe Introduction rules
  1321 to the claset;
  1322 
  1323 * the syntax "if P then x else y" is now available in addition to
  1324 if(P,x,y);
  1325 
  1326 
  1327 *** Internal programming interfaces ***
  1328 
  1329 * tuned simplifier trace output; new flag debug_simp;
  1330 
  1331 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1332 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1333 
  1334 * AxClass.axclass_tac lost the theory argument;
  1335 
  1336 * tuned current_goals_markers semantics: begin / end goal avoids
  1337 printing empty lines;
  1338 
  1339 * removed prs and prs_fn hook, which was broken because it did not
  1340 include \n in its semantics, forcing writeln to add one
  1341 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1342 string -> unit if you really want to output text without newline;
  1343 
  1344 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1345 plain output, interface builders may have to enable 'isabelle_font'
  1346 mode to get Isabelle font glyphs as before;
  1347 
  1348 * refined token_translation interface; INCOMPATIBILITY: output length
  1349 now of type real instead of int;
  1350 
  1351 * theory loader actions may be traced via new ThyInfo.add_hook
  1352 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1353 your own database of information attached to *whole* theories -- as
  1354 opposed to intra-theory data slots offered via TheoryDataFun;
  1355 
  1356 * proper handling of dangling sort hypotheses (at last!);
  1357 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1358 extra sort hypotheses that can be witnessed from the type signature;
  1359 the force_strip_shyps flag is gone, any remaining shyps are simply
  1360 left in the theorem (with a warning issued by strip_shyps_warning);
  1361 
  1362 
  1363 
  1364 New in Isabelle98-1 (October 1998)
  1365 ----------------------------------
  1366 
  1367 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1368 
  1369 * several changes of automated proof tools;
  1370 
  1371 * HOL: major changes to the inductive and datatype packages, including
  1372 some minor incompatibilities of theory syntax;
  1373 
  1374 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1375 called `inj_on';
  1376 
  1377 * HOL: removed duplicate thms in Arith:
  1378   less_imp_add_less  should be replaced by  trans_less_add1
  1379   le_imp_add_le      should be replaced by  trans_le_add1
  1380 
  1381 * HOL: unary minus is now overloaded (new type constraints may be
  1382 required);
  1383 
  1384 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1385 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1386 now taken as an integer constant.
  1387 
  1388 * Pure: ML function 'theory_of' renamed to 'theory';
  1389 
  1390 
  1391 *** Proof tools ***
  1392 
  1393 * Simplifier:
  1394   1. Asm_full_simp_tac is now more aggressive.
  1395      1. It will sometimes reorient premises if that increases their power to
  1396         simplify.
  1397      2. It does no longer proceed strictly from left to right but may also
  1398         rotate premises to achieve further simplification.
  1399      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1400      old Asm_full_simp_tac in that it does not rotate premises.
  1401   2. The simplifier now knows a little bit about nat-arithmetic.
  1402 
  1403 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1404 allows for selected deletion of wrappers, by introduction of names for
  1405 wrapper functionals.  This implies that addbefore, addSbefore,
  1406 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1407 and that adding two tactics with the same name overwrites the first
  1408 one (emitting a warning).
  1409   type wrapper = (int -> tactic) -> (int -> tactic)
  1410   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1411   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1412   delWrapper, delSWrapper: claset *  string            -> claset
  1413   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1414 
  1415 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1416 semantics; addbefore now affects only the unsafe part of step_tac
  1417 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1418 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1419 by Force_tac;
  1420 
  1421 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1422 compWrapper; added safe wrapper (and access functions for it);
  1423 
  1424 * HOL/split_all_tac is now much faster and fails if there is nothing
  1425 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1426 and the names of the automatically generated variables have changed.
  1427 split_all_tac has moved within claset() from unsafe wrappers to safe
  1428 wrappers, which means that !!-bound variables are split much more
  1429 aggressively, and safe_tac and clarify_tac now split such variables.
  1430 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1431 Note: the same holds for record_split_tac, which does the job of
  1432 split_all_tac for record fields.
  1433 
  1434 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1435 permanently to the default simpset using Addsplits just like
  1436 Addsimps. They can be removed via Delsplits just like
  1437 Delsimps. Lower-case versions are also available.
  1438 
  1439 * HOL/Simplifier: The rule split_if is now part of the default
  1440 simpset. This means that the simplifier will eliminate all occurrences
  1441 of if-then-else in the conclusion of a goal. To prevent this, you can
  1442 either remove split_if completely from the default simpset by
  1443 `Delsplits [split_if]' or remove it in a specific call of the
  1444 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1445 other case splitting rules to/from the default simpset: every datatype
  1446 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1447 t is the name of the datatype).
  1448 
  1449 * Classical reasoner / Simplifier combination: new force_tac (and
  1450 derivatives Force_tac, force) combines rewriting and classical
  1451 reasoning (and whatever other tools) similarly to auto_tac, but is
  1452 aimed to solve the given subgoal completely.
  1453 
  1454 
  1455 *** General ***
  1456 
  1457 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1458 and `goalw': the theory is no longer needed as an explicit argument -
  1459 the current theory context is used; assumptions are no longer returned
  1460 at the ML-level unless one of them starts with ==> or !!; it is
  1461 recommended to convert to these new commands using isatool fixgoal
  1462 (backup your sources first!);
  1463 
  1464 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1465 the current theory context, and 'theory' to lookup stored theories;
  1466 
  1467 * new theory section 'locale' for declaring constants, assumptions and
  1468 definitions that have local scope;
  1469 
  1470 * new theory section 'nonterminals' for purely syntactic types;
  1471 
  1472 * new theory section 'setup' for generic ML setup functions
  1473 (e.g. package initialization);
  1474 
  1475 * the distribution now includes Isabelle icons: see
  1476 lib/logo/isabelle-{small,tiny}.xpm;
  1477 
  1478 * isatool install - install binaries with absolute references to
  1479 ISABELLE_HOME/bin;
  1480 
  1481 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1482 
  1483 * print mode 'emacs' reserved for Isamode;
  1484 
  1485 * support multiple print (ast) translations per constant name;
  1486 
  1487 * theorems involving oracles are now printed with a suffixed [!];
  1488 
  1489 
  1490 *** HOL ***
  1491 
  1492 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1493 
  1494 * HOL/inductive package reorganized and improved: now supports mutual
  1495 definitions such as
  1496 
  1497   inductive EVEN ODD
  1498     intrs
  1499       null "0 : EVEN"
  1500       oddI "n : EVEN ==> Suc n : ODD"
  1501       evenI "n : ODD ==> Suc n : EVEN"
  1502 
  1503 new theorem list "elims" contains an elimination rule for each of the
  1504 recursive sets; inductive definitions now handle disjunctive premises
  1505 correctly (also ZF);
  1506 
  1507 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1508 "mutual_induct" no longer exists - the induction rule is always
  1509 contained in "induct";
  1510 
  1511 
  1512 * HOL/datatype package re-implemented and greatly improved: now
  1513 supports mutually recursive datatypes such as
  1514 
  1515   datatype
  1516     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1517             | SUM ('a aexp) ('a aexp)
  1518             | DIFF ('a aexp) ('a aexp)
  1519             | NUM 'a
  1520   and
  1521     'a bexp = LESS ('a aexp) ('a aexp)
  1522             | AND ('a bexp) ('a bexp)
  1523             | OR ('a bexp) ('a bexp)
  1524 
  1525 as well as indirectly recursive datatypes such as
  1526 
  1527   datatype
  1528     ('a, 'b) term = Var 'a
  1529                   | App 'b ((('a, 'b) term) list)
  1530 
  1531 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1532 induction on mutually / indirectly recursive datatypes.
  1533 
  1534 Primrec equations are now stored in theory and can be accessed via
  1535 <function_name>.simps.
  1536 
  1537 INCOMPATIBILITIES:
  1538 
  1539   - Theories using datatypes must now have theory Datatype as an
  1540     ancestor.
  1541   - The specific <typename>.induct_tac no longer exists - use the
  1542     generic induct_tac instead.
  1543   - natE has been renamed to nat.exhaust - use exhaust_tac
  1544     instead of res_inst_tac ... natE. Note that the variable
  1545     names in nat.exhaust differ from the names in natE, this
  1546     may cause some "fragile" proofs to fail.
  1547   - The theorems split_<typename>_case and split_<typename>_case_asm
  1548     have been renamed to <typename>.split and <typename>.split_asm.
  1549   - Since default sorts of type variables are now handled correctly,
  1550     some datatype definitions may have to be annotated with explicit
  1551     sort constraints.
  1552   - Primrec definitions no longer require function name and type
  1553     of recursive argument.
  1554 
  1555 Consider using isatool fixdatatype to adapt your theories and proof
  1556 scripts to the new package (backup your sources first!).
  1557 
  1558 
  1559 * HOL/record package: considerably improved implementation; now
  1560 includes concrete syntax for record types, terms, updates; theorems
  1561 for surjective pairing and splitting !!-bound record variables; proof
  1562 support is as follows:
  1563 
  1564   1) standard conversions (selectors or updates applied to record
  1565 constructor terms) are part of the standard simpset;
  1566 
  1567   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1568 made part of standard simpset and claset via addIffs;
  1569 
  1570   3) a tactic for record field splitting (record_split_tac) is part of
  1571 the standard claset (addSWrapper);
  1572 
  1573 To get a better idea about these rules you may retrieve them via
  1574 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1575 the name of your record type.
  1576 
  1577 The split tactic 3) conceptually simplifies by the following rule:
  1578 
  1579   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1580 
  1581 Thus any record variable that is bound by meta-all will automatically
  1582 blow up into some record constructor term, consequently the
  1583 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1584 solve record problems automatically.
  1585 
  1586 
  1587 * reorganized the main HOL image: HOL/Integ and String loaded by
  1588 default; theory Main includes everything;
  1589 
  1590 * automatic simplification of integer sums and comparisons, using cancellation;
  1591 
  1592 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1593 
  1594 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1595 
  1596 * many new identities for unions, intersections, set difference, etc.;
  1597 
  1598 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1599 called split_if, split_split, split_sum_case and split_nat_case (to go
  1600 with add/delsplits);
  1601 
  1602 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1603 (?x::unit) = (); this is made part of the default simpset, which COULD
  1604 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1605 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1606 unit_abs_eta_conv is added in order to counter the effect of
  1607 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1608 %u.f();
  1609 
  1610 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1611 makes more sense);
  1612 
  1613 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1614   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1615   disjointness reasoning but breaking a few old proofs.
  1616 
  1617 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1618 to 'converse' from 'inverse' (for compatibility with ZF and some
  1619 literature);
  1620 
  1621 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1622 the well-founded relation;
  1623 
  1624 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1625     Compl A.  The "Compl" syntax remains available as input syntax for this
  1626     release ONLY.
  1627 
  1628 * HOL/Update: new theory of function updates:
  1629     f(a:=b) == %x. if x=a then b else f x
  1630 may also be iterated as in f(a:=b,c:=d,...);
  1631 
  1632 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1633 
  1634 * HOL/List:
  1635   - new function list_update written xs[i:=v] that updates the i-th
  1636     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1637   - new function `upt' written [i..j(] which generates the list
  1638     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1639     bound write [i..j], which is a shorthand for [i..j+1(].
  1640   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1641 
  1642 * HOL/Arith:
  1643   - removed 'pred' (predecessor) function;
  1644   - generalized some theorems about n-1;
  1645   - many new laws about "div" and "mod";
  1646   - new laws about greatest common divisors (see theory ex/Primes);
  1647 
  1648 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1649 instead of "inverse";
  1650 
  1651 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1652   of the multiset ordering;
  1653 
  1654 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1655   (not included by default);
  1656 
  1657 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1658 
  1659 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1660   programs, i.e. different program variables may have different types.
  1661 
  1662 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1663   [previously, this check worked only if the rewrite rule was unconditional]
  1664   Now rew can involve either definitions or equalities (either == or =).
  1665 
  1666 
  1667 *** ZF ***
  1668 
  1669 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1670   only the theorems proved on ZF.ML;
  1671 
  1672 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1673   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1674   disjointness reasoning but breaking a few old proofs.
  1675 
  1676 * ZF/Update: new theory of function updates
  1677     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1678   may also be iterated as in f(a:=b,c:=d,...);
  1679 
  1680 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1681 
  1682 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1683   [previously, this check worked only if the rewrite rule was unconditional]
  1684   Now rew can involve either definitions or equalities (either == or =).
  1685 
  1686 * case_tac provided for compatibility with HOL
  1687     (like the old excluded_middle_tac, but with subgoals swapped)
  1688 
  1689 
  1690 *** Internal programming interfaces ***
  1691 
  1692 * Pure: several new basic modules made available for general use, see
  1693 also src/Pure/README;
  1694 
  1695 * improved the theory data mechanism to support encapsulation (data
  1696 kind name replaced by private Object.kind, acting as authorization
  1697 key); new type-safe user interface via functor TheoryDataFun; generic
  1698 print_data function becomes basically useless;
  1699 
  1700 * removed global_names compatibility flag -- all theory declarations
  1701 are qualified by default;
  1702 
  1703 * module Pure/Syntax now offers quote / antiquote translation
  1704 functions (useful for Hoare logic etc. with implicit dependencies);
  1705 see HOL/ex/Antiquote for an example use;
  1706 
  1707 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1708 cterm -> thm;
  1709 
  1710 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1711 subgoal;
  1712 
  1713 * Display.print_goals function moved to Locale.print_goals;
  1714 
  1715 * standard print function for goals supports current_goals_markers
  1716 variable for marking begin of proof, end of proof, start of goal; the
  1717 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1718 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1719 for example;
  1720 
  1721 
  1722 
  1723 New in Isabelle98 (January 1998)
  1724 --------------------------------
  1725 
  1726 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1727 
  1728 * changed lexical syntax of terms / types: dots made part of long
  1729 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1730 
  1731 * simpset (and claset) reference variable replaced by functions
  1732 simpset / simpset_ref;
  1733 
  1734 * no longer supports theory aliases (via merge) and non-trivial
  1735 implicit merge of thms' signatures;
  1736 
  1737 * most internal names of constants changed due to qualified names;
  1738 
  1739 * changed Pure/Sequence interface (see Pure/seq.ML);
  1740 
  1741 
  1742 *** General Changes ***
  1743 
  1744 * hierachically structured name spaces (for consts, types, axms, thms
  1745 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1746 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1747 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1748 long_names for fully qualified output names; NOTE: ML programs
  1749 (special tactics, packages etc.) referring to internal names may have
  1750 to be adapted to cope with fully qualified names; in case of severe
  1751 backward campatibility problems try setting 'global_names' at compile
  1752 time to have enrything declared within a flat name space; one may also
  1753 fine tune name declarations in theories via the 'global' and 'local'
  1754 section;
  1755 
  1756 * reimplemented the implicit simpset and claset using the new anytype
  1757 data filed in signatures; references simpset:simpset ref etc. are
  1758 replaced by functions simpset:unit->simpset and
  1759 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1760 to patch your ML files accordingly;
  1761 
  1762 * HTML output now includes theory graph data for display with Java
  1763 applet or isatool browser; data generated automatically via isatool
  1764 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1765 
  1766 * defs may now be conditional; improved rewrite_goals_tac to handle
  1767 conditional equations;
  1768 
  1769 * defs now admits additional type arguments, using TYPE('a) syntax;
  1770 
  1771 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1772 creates a new theory node; implicit merge of thms' signatures is
  1773 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1774 transfer:theory->thm->thm in (rare) cases;
  1775 
  1776 * improved handling of draft signatures / theories; draft thms (and
  1777 ctyps, cterms) are automatically promoted to real ones;
  1778 
  1779 * slightly changed interfaces for oracles: admit many per theory, named
  1780 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1781 
  1782 * print_goals: optional output of const types (set show_consts and
  1783 show_types);
  1784 
  1785 * improved output of warnings (###) and errors (***);
  1786 
  1787 * subgoal_tac displays a warning if the new subgoal has type variables;
  1788 
  1789 * removed old README and Makefiles;
  1790 
  1791 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1792 
  1793 * removed obsolete init_pps and init_database;
  1794 
  1795 * deleted the obsolete tactical STATE, which was declared by
  1796     fun STATE tacfun st = tacfun st st;
  1797 
  1798 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1799 (which abbreviates $HOME);
  1800 
  1801 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1802 use isatool fixseq to adapt your ML programs (this works for fully
  1803 qualified references to the Sequence structure only!);
  1804 
  1805 * use_thy no longer requires writable current directory; it always
  1806 reloads .ML *and* .thy file, if either one is out of date;
  1807 
  1808 
  1809 *** Classical Reasoner ***
  1810 
  1811 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1812 tactics that use classical reasoning to simplify a subgoal without
  1813 splitting it into several subgoals;
  1814 
  1815 * Safe_tac: like safe_tac but uses the default claset;
  1816 
  1817 
  1818 *** Simplifier ***
  1819 
  1820 * added simplification meta rules:
  1821     (asm_)(full_)simplify: simpset -> thm -> thm;
  1822 
  1823 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1824 logics (again);
  1825 
  1826 * added prems argument to simplification procedures;
  1827 
  1828 * HOL, FOL, ZF: added infix function `addsplits':
  1829   instead of `<simpset> setloop (split_tac <thms>)'
  1830   you can simply write `<simpset> addsplits <thms>'
  1831 
  1832 
  1833 *** Syntax ***
  1834 
  1835 * TYPE('a) syntax for type reflection terms;
  1836 
  1837 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1838 
  1839 * pretty printer: changed order of mixfix annotation preference (again!);
  1840 
  1841 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1842 
  1843 
  1844 *** HOL ***
  1845 
  1846 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1847   with `addloop' of the simplifier to faciliate case splitting in premises.
  1848 
  1849 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1850 
  1851 * HOL/Auth: new protocol proofs including some for the Internet
  1852   protocol TLS;
  1853 
  1854 * HOL/Map: new theory of `maps' a la VDM;
  1855 
  1856 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1857 cancelling out common nat summands from =, <, <= (in)equalities, or
  1858 differences; simplification procedures nat_cancel_factor for
  1859 cancelling common factor from =, <, <= (in)equalities over natural
  1860 sums; nat_cancel contains both kinds of procedures, it is installed by
  1861 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1862 
  1863 * HOL/simplifier: terms of the form
  1864   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1865   are rewritten to
  1866   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1867   and those of the form
  1868   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1869   are rewritten to
  1870   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1871 
  1872 * HOL/datatype
  1873   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1874 
  1875   P(t_case f1 ... fn x) =
  1876      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1877         ...
  1878        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1879      )
  1880 
  1881   and a theorem `split_t_case_asm' of the form
  1882 
  1883   P(t_case f1 ... fn x) =
  1884     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1885         ...
  1886        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1887      )
  1888   which can be added to a simpset via `addsplits'. The existing theorems
  1889   expand_list_case and expand_option_case have been renamed to
  1890   split_list_case and split_option_case.
  1891 
  1892 * HOL/Arithmetic:
  1893   - `pred n' is automatically converted to `n-1'.
  1894     Users are strongly encouraged not to use `pred' any longer,
  1895     because it will disappear altogether at some point.
  1896   - Users are strongly encouraged to write "0 < n" rather than
  1897     "n ~= 0". Theorems and proof tools have been modified towards this
  1898     `standard'.
  1899 
  1900 * HOL/Lists:
  1901   the function "set_of_list" has been renamed "set" (and its theorems too);
  1902   the function "nth" now takes its arguments in the reverse order and
  1903   has acquired the infix notation "!" as in "xs!n".
  1904 
  1905 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1906 
  1907 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1908   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1909 
  1910 * HOL/record: extensible records with schematic structural subtyping
  1911 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1912 still lacks various theorems and concrete record syntax;
  1913 
  1914 
  1915 *** HOLCF ***
  1916 
  1917 * removed "axioms" and "generated by" sections;
  1918 
  1919 * replaced "ops" section by extended "consts" section, which is capable of
  1920   handling the continuous function space "->" directly;
  1921 
  1922 * domain package:
  1923   . proves theorems immediately and stores them in the theory,
  1924   . creates hierachical name space,
  1925   . now uses normal mixfix annotations (instead of cinfix...),
  1926   . minor changes to some names and values (for consistency),
  1927   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1928   . separator between mutual domain defs: changed "," to "and",
  1929   . improved handling of sort constraints;  now they have to
  1930     appear on the left-hand side of the equations only;
  1931 
  1932 * fixed LAM <x,y,zs>.b syntax;
  1933 
  1934 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1935 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1936 
  1937 
  1938 *** FOL and ZF ***
  1939 
  1940 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1941   with `addloop' of the simplifier to faciliate case splitting in premises.
  1942 
  1943 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1944 in HOL, they strip ALL and --> from proved theorems;
  1945 
  1946 
  1947 
  1948 New in Isabelle94-8 (May 1997)
  1949 ------------------------------
  1950 
  1951 *** General Changes ***
  1952 
  1953 * new utilities to build / run / maintain Isabelle etc. (in parts
  1954 still somewhat experimental); old Makefiles etc. still functional;
  1955 
  1956 * new 'Isabelle System Manual';
  1957 
  1958 * INSTALL text, together with ./configure and ./build scripts;
  1959 
  1960 * reimplemented type inference for greater efficiency, better error
  1961 messages and clean internal interface;
  1962 
  1963 * prlim command for dealing with lots of subgoals (an easier way of
  1964 setting goals_limit);
  1965 
  1966 
  1967 *** Syntax ***
  1968 
  1969 * supports alternative (named) syntax tables (parser and pretty
  1970 printer); internal interface is provided by add_modesyntax(_i);
  1971 
  1972 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1973 be used in conjunction with the Isabelle symbol font; uses the
  1974 "symbols" syntax table;
  1975 
  1976 * added token_translation interface (may translate name tokens in
  1977 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1978 the current print_mode); IMPORTANT: user print translation functions
  1979 are responsible for marking newly introduced bounds
  1980 (Syntax.mark_boundT);
  1981 
  1982 * token translations for modes "xterm" and "xterm_color" that display
  1983 names in bold, underline etc. or colors (which requires a color
  1984 version of xterm);
  1985 
  1986 * infixes may now be declared with names independent of their syntax;
  1987 
  1988 * added typed_print_translation (like print_translation, but may
  1989 access type of constant);
  1990 
  1991 
  1992 *** Classical Reasoner ***
  1993 
  1994 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1995 some limitations.  Blast_tac...
  1996   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1997   + ignores elimination rules that don't have the correct format
  1998         (the conclusion MUST be a formula variable)
  1999   + ignores types, which can make HOL proofs fail
  2000   + rules must not require higher-order unification, e.g. apply_type in ZF
  2001     [message "Function Var's argument not a bound variable" relates to this]
  2002   + its proof strategy is more general but can actually be slower
  2003 
  2004 * substitution with equality assumptions no longer permutes other
  2005 assumptions;
  2006 
  2007 * minor changes in semantics of addafter (now called addaltern); renamed
  2008 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2009 (and access functions for it);
  2010 
  2011 * improved combination of classical reasoner and simplifier:
  2012   + functions for handling clasimpsets
  2013   + improvement of addss: now the simplifier is called _after_ the
  2014     safe steps.
  2015   + safe variant of addss called addSss: uses safe simplifications
  2016     _during_ the safe steps. It is more complete as it allows multiple
  2017     instantiations of unknowns (e.g. with slow_tac).
  2018 
  2019 *** Simplifier ***
  2020 
  2021 * added interface for simplification procedures (functions that
  2022 produce *proven* rewrite rules on the fly, depending on current
  2023 redex);
  2024 
  2025 * ordering on terms as parameter (used for ordered rewriting);
  2026 
  2027 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2028 
  2029 * the solver is now split into a safe and an unsafe part.
  2030 This should be invisible for the normal user, except that the
  2031 functions setsolver and addsolver have been renamed to setSolver and
  2032 addSolver; added safe_asm_full_simp_tac;
  2033 
  2034 
  2035 *** HOL ***
  2036 
  2037 * a generic induction tactic `induct_tac' which works for all datatypes and
  2038 also for type `nat';
  2039 
  2040 * a generic case distinction tactic `exhaust_tac' which works for all
  2041 datatypes and also for type `nat';
  2042 
  2043 * each datatype comes with a function `size';
  2044 
  2045 * patterns in case expressions allow tuple patterns as arguments to
  2046 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2047 
  2048 * primrec now also works with type nat;
  2049 
  2050 * recdef: a new declaration form, allows general recursive functions to be
  2051 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2052 
  2053 * the constant for negation has been renamed from "not" to "Not" to
  2054 harmonize with FOL, ZF, LK, etc.;
  2055 
  2056 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2057 infinite lists;
  2058 
  2059 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2060 
  2061 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2062 problems in commutative rings, using axiomatic type classes for + and *;
  2063 
  2064 * more examples in HOL/MiniML and HOL/Auth;
  2065 
  2066 * more default rewrite rules for quantifiers, union/intersection;
  2067 
  2068 * a new constant `arbitrary == @x.False';
  2069 
  2070 * HOLCF/IOA replaces old HOL/IOA;
  2071 
  2072 * HOLCF changes: derived all rules and arities
  2073   + axiomatic type classes instead of classes
  2074   + typedef instead of faking type definitions
  2075   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2076   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2077   + eliminated the types void, one, tr
  2078   + use unit lift and bool lift (with translations) instead of one and tr
  2079   + eliminated blift from Lift3.thy (use Def instead of blift)
  2080   all eliminated rules are derived as theorems --> no visible changes ;
  2081 
  2082 
  2083 *** ZF ***
  2084 
  2085 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2086 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2087 as ZF_cs addSIs [equalityI];
  2088 
  2089 
  2090 
  2091 New in Isabelle94-7 (November 96)
  2092 ---------------------------------
  2093 
  2094 * allowing negative levels (as offsets) in prlev and choplev;
  2095 
  2096 * super-linear speedup for large simplifications;
  2097 
  2098 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2099 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2100 FAIL); can suppress it using the command Delsimps (ex_simps @
  2101 all_simps); De Morgan laws are also now included, by default;
  2102 
  2103 * improved printing of ==>  :  ~:
  2104 
  2105 * new object-logic "Sequents" adds linear logic, while replacing LK
  2106 and Modal (thanks to Sara Kalvala);
  2107 
  2108 * HOL/Auth: correctness proofs for authentication protocols;
  2109 
  2110 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2111 examples on HOL/Auth);
  2112 
  2113 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2114 the rewriter and classical reasoner simultaneously;
  2115 
  2116 * function uresult no longer returns theorems in "standard" format;
  2117 regain previous version by: val uresult = standard o uresult;
  2118 
  2119 
  2120 
  2121 New in Isabelle94-6
  2122 -------------------
  2123 
  2124 * oracles -- these establish an interface between Isabelle and trusted
  2125 external reasoners, which may deliver results as theorems;
  2126 
  2127 * proof objects (in particular record all uses of oracles);
  2128 
  2129 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2130 
  2131 * "constdefs" section in theory files;
  2132 
  2133 * "primrec" section (HOL) no longer requires names;
  2134 
  2135 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2136 
  2137 
  2138 
  2139 New in Isabelle94-5
  2140 -------------------
  2141 
  2142 * reduced space requirements;
  2143 
  2144 * automatic HTML generation from theories;
  2145 
  2146 * theory files no longer require "..." (quotes) around most types;
  2147 
  2148 * new examples, including two proofs of the Church-Rosser theorem;
  2149 
  2150 * non-curried (1994) version of HOL is no longer distributed;
  2151 
  2152 
  2153 
  2154 New in Isabelle94-4
  2155 -------------------
  2156 
  2157 * greatly reduced space requirements;
  2158 
  2159 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2160 
  2161 * searchable theorem database (see the section "Retrieving theorems" on
  2162 page 8 of the Reference Manual);
  2163 
  2164 * new examples, including Grabczewski's monumental case study of the
  2165 Axiom of Choice;
  2166 
  2167 * The previous version of HOL renamed to Old_HOL;
  2168 
  2169 * The new version of HOL (previously called CHOL) uses a curried syntax
  2170 for functions.  Application looks like f a b instead of f(a,b);
  2171 
  2172 * Mutually recursive inductive definitions finally work in HOL;
  2173 
  2174 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2175 translates to the operator "split";
  2176 
  2177 
  2178 
  2179 New in Isabelle94-3
  2180 -------------------
  2181 
  2182 * new infix operator, addss, allowing the classical reasoner to
  2183 perform simplification at each step of its search.  Example:
  2184         fast_tac (cs addss ss)
  2185 
  2186 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2187 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2188 look like (a,b) instead of <a,b>;
  2189 
  2190 * PLEASE NOTE: CHOL will eventually replace HOL!
  2191 
  2192 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2193 It translates to the operator "split".  A new theory of integers is available;
  2194 
  2195 * In ZF, integer numerals now denote two's-complement binary integers.
  2196 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2197 
  2198 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2199 of the Axiom of Choice;
  2200 
  2201 
  2202 
  2203 New in Isabelle94-2
  2204 -------------------
  2205 
  2206 * Significantly faster resolution;
  2207 
  2208 * the different sections in a .thy file can now be mixed and repeated
  2209 freely;
  2210 
  2211 * Database of theorems for FOL, HOL and ZF.  New
  2212 commands including qed, qed_goal and bind_thm store theorems in the database.
  2213 
  2214 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2215 a given theory (thms_of), or find out what theory a theorem was proved in
  2216 (theory_of_thm);
  2217 
  2218 * Bugs fixed in the inductive definition and datatype packages;
  2219 
  2220 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2221 and HOL_dup_cs obsolete;
  2222 
  2223 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2224 have been removed;
  2225 
  2226 * Simpler definition of function space in ZF;
  2227 
  2228 * new results about cardinal and ordinal arithmetic in ZF;
  2229 
  2230 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2231 types;
  2232 
  2233 
  2234 $Id$