NEWS
author nipkow
Thu Jul 11 09:31:01 2002 +0200 (2002-07-11)
changeset 13344 c8eb3fbf4c0c
parent 13284 20c818c966e6
child 13410 f2cd09766864
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * improved thms_containing: proper indexing of facts instead of raw
    10 theorems; check validity of results wrt. current name space; include
    11 local facts of proof configuration (also covers active locales); an
    12 optional limit for the number of printed facts may be given (the
    13 default is 40);
    14 
    15 
    16 *** HOL ***
    17 
    18 * attribute [symmetric] now works for relations as well. It turns
    19   (x,y) : R^-1 into (y,x) : R, and vice versa.
    20 
    21 * arith(_tac) does now know about div k and mod k where k is a numeral of
    22   type nat or int. It can solve simple goals like
    23   "0 < n ==> n div 2 < (n::nat)"
    24   but fails if divisibility plays a role like in
    25   "n div 2 + (n+1) div 2 = (n::nat)".
    26 * simp's arithmetic capabilities have been enhanced a bit:
    27   it now takes ~= in premises into account (by performing a case split).
    28 
    29 
    30 
    31 New in Isabelle2002 (March 2002)
    32 --------------------------------
    33 
    34 *** Document preparation ***
    35 
    36 * greatly simplified document preparation setup, including more
    37 graceful interpretation of isatool usedir -i/-d/-D options, and more
    38 instructive isatool mkdir; users should basically be able to get
    39 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    40 users may run a separate document processing stage manually like this:
    41 "isatool usedir -D output HOL Test && isatool document Test/output";
    42 
    43 * theory dependency graph may now be incorporated into documents;
    44 isatool usedir -g true will produce session_graph.eps/.pdf for use
    45 with \includegraphics of LaTeX;
    46 
    47 * proper spacing of consecutive markup elements, especially text
    48 blocks after section headings;
    49 
    50 * support bold style (for single symbols only), input syntax is like
    51 this: "\<^bold>\<alpha>" or "\<^bold>A";
    52 
    53 * \<bullet> is now output as bold \cdot by default, which looks much
    54 better in printed text;
    55 
    56 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    57 note that these symbols are currently unavailable in Proof General /
    58 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
    59 
    60 * isatool latex no longer depends on changed TEXINPUTS, instead
    61 isatool document copies the Isabelle style files to the target
    62 location;
    63 
    64 
    65 *** Isar ***
    66 
    67 * Pure/Provers: improved proof by cases and induction;
    68   - 'case' command admits impromptu naming of parameters (such as
    69     "case (Suc n)");
    70   - 'induct' method divinates rule instantiation from the inductive
    71     claim; no longer requires excessive ?P bindings for proper
    72     instantiation of cases;
    73   - 'induct' method properly enumerates all possibilities of set/type
    74     rules; as a consequence facts may be also passed through *type*
    75     rules without further ado;
    76   - 'induct' method now derives symbolic cases from the *rulified*
    77     rule (before it used to rulify cases stemming from the internal
    78     atomized version); this means that the context of a non-atomic
    79     statement becomes is included in the hypothesis, avoiding the
    80     slightly cumbersome show "PROP ?case" form;
    81   - 'induct' may now use elim-style induction rules without chaining
    82     facts, using ``missing'' premises from the goal state; this allows
    83     rules stemming from inductive sets to be applied in unstructured
    84     scripts, while still benefitting from proper handling of non-atomic
    85     statements; NB: major inductive premises need to be put first, all
    86     the rest of the goal is passed through the induction;
    87   - 'induct' proper support for mutual induction involving non-atomic
    88     rule statements (uses the new concept of simultaneous goals, see
    89     below);
    90   - append all possible rule selections, but only use the first
    91     success (no backtracking);
    92   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    93   - undeclared rule case names default to numbers 1, 2, 3, ...;
    94   - added 'print_induct_rules' (covered by help item in recent Proof
    95     General versions);
    96   - moved induct/cases attributes to Pure, methods to Provers;
    97   - generic method setup instantiated for FOL and HOL;
    98 
    99 * Pure: support multiple simultaneous goal statements, for example
   100 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   101 meta-level mechanism, this acts as if several individual goals had
   102 been stated separately; in particular common proof methods need to be
   103 repeated in order to cover all claims; note that a single elimination
   104 step is *not* sufficient to establish the two conjunctions, so this
   105 fails:
   106 
   107   assume "A & B" then have A and B ..   (*".." fails*)
   108 
   109 better use "obtain" in situations as above; alternative refer to
   110 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   111 
   112 * Pure: proper integration with ``locales''; unlike the original
   113 version by Florian Kammüller, Isar locales package high-level proof
   114 contexts rather than raw logical ones (e.g. we admit to include
   115 attributes everywhere); operations on locales include merge and
   116 rename; support for implicit arguments (``structures''); simultaneous
   117 type-inference over imports and text; see also HOL/ex/Locales.thy for
   118 some examples;
   119 
   120 * Pure: the following commands have been ``localized'', supporting a
   121 target locale specification "(in name)": 'lemma', 'theorem',
   122 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   123 stored both within the locale and at the theory level (exported and
   124 qualified by the locale name);
   125 
   126 * Pure: theory goals may now be specified in ``long'' form, with
   127 ad-hoc contexts consisting of arbitrary locale elements. for example
   128 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   129 definitions may be given, too); the result is a meta-level rule with
   130 the context elements being discharged in the obvious way;
   131 
   132 * Pure: new proof command 'using' allows to augment currently used
   133 facts after a goal statement ('using' is syntactically analogous to
   134 'apply', but acts on the goal's facts only); this allows chained facts
   135 to be separated into parts given before and after a claim, as in
   136 ``from a and b have C using d and e <proof>'';
   137 
   138 * Pure: renamed "antecedent" case to "rule_context";
   139 
   140 * Pure: new 'judgment' command records explicit information about the
   141 object-logic embedding (used by several tools internally); no longer
   142 use hard-wired "Trueprop";
   143 
   144 * Pure: added 'corollary' command;
   145 
   146 * Pure: fixed 'token_translation' command;
   147 
   148 * Pure: removed obsolete 'exported' attribute;
   149 
   150 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   151 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   152 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   153 
   154 * Pure: method 'atomize' presents local goal premises as object-level
   155 statements (atomic meta-level propositions); setup controlled via
   156 rewrite rules declarations of 'atomize' attribute; example
   157 application: 'induct' method with proper rule statements in improper
   158 proof *scripts*;
   159 
   160 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   161 now consider the syntactic context of assumptions, giving a better
   162 chance to get type-inference of the arguments right (this is
   163 especially important for locales);
   164 
   165 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   166 mode;
   167 
   168 * Pure/obtain: the formal conclusion "thesis", being marked as
   169 ``internal'', may no longer be reference directly in the text;
   170 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   171 situations;
   172 
   173 * Pure: generic 'sym' attribute which declares a rule both as pure
   174 'elim?' and for the 'symmetric' operation;
   175 
   176 * Pure: marginal comments ``--'' may now occur just anywhere in the
   177 text; the fixed correlation with particular command syntax has been
   178 discontinued;
   179 
   180 * Pure: new method 'rules' is particularly well-suited for proof
   181 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   182 but often produces more compact proof terms with less detours;
   183 
   184 * Pure/Provers/classical: simplified integration with pure rule
   185 attributes and methods; the classical "intro?/elim?/dest?"
   186 declarations coincide with the pure ones; the "rule" method no longer
   187 includes classically swapped intros; "intro" and "elim" methods no
   188 longer pick rules from the context; also got rid of ML declarations
   189 AddXIs/AddXEs/AddXDs; all of this has some potential for
   190 INCOMPATIBILITY;
   191 
   192 * Provers/classical: attribute 'swapped' produces classical inversions
   193 of introduction rules;
   194 
   195 * Provers/simplifier: 'simplified' attribute may refer to explicit
   196 rules instead of full simplifier context; 'iff' attribute handles
   197 conditional rules;
   198 
   199 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   200 
   201 * HOL: 'recdef' now fails on unfinished automated proofs, use
   202 "(permissive)" option to recover old behavior;
   203 
   204 * HOL: 'inductive' no longer features separate (collective) attributes
   205 for 'intros' (was found too confusing);
   206 
   207 * HOL: properly declared induction rules less_induct and
   208 wf_induct_rule;
   209 
   210 
   211 *** HOL ***
   212 
   213 * HOL: moved over to sane numeral syntax; the new policy is as
   214 follows:
   215 
   216   - 0 and 1 are polymorphic constants, which are defined on any
   217   numeric type (nat, int, real etc.);
   218 
   219   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   220   binary representation internally;
   221 
   222   - type nat has special constructor Suc, and generally prefers Suc 0
   223   over 1::nat and Suc (Suc 0) over 2::nat;
   224 
   225 This change may cause significant problems of INCOMPATIBILITY; here
   226 are some hints on converting existing sources:
   227 
   228   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   229   entities, so expressions involving "-" (unary or binary minus) need
   230   to be spaced properly;
   231 
   232   - existing occurrences of "1" may need to be constraint "1::nat" or
   233   even replaced by Suc 0; similar for old "2";
   234 
   235   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   236 
   237   - remove all special provisions on numerals in proofs;
   238 
   239 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   240 representation (depends on bin_arith_simps in the default context);
   241 
   242 * HOL: symbolic syntax for x^2 (numeral 2);
   243 
   244 * HOL: the class of all HOL types is now called "type" rather than
   245 "term"; INCOMPATIBILITY, need to adapt references to this type class
   246 in axclass/classes, instance/arities, and (usually rare) occurrences
   247 in typings (of consts etc.); internally the class is called
   248 "HOL.type", ML programs should refer to HOLogic.typeS;
   249 
   250 * HOL/record package improvements:
   251   - new derived operations "fields" to build a partial record section,
   252     "extend" to promote a fixed record to a record scheme, and
   253     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   254     declared as simp by default;
   255   - shared operations ("more", "fields", etc.) now need to be always
   256     qualified) --- potential INCOMPATIBILITY;
   257   - removed "make_scheme" operations (use "make" with "extend") --
   258     INCOMPATIBILITY;
   259   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   260   - provides cases/induct rules for use with corresponding Isar
   261     methods (for concrete records, record schemes, concrete more
   262     parts, and schematic more parts -- in that order);
   263   - internal definitions directly based on a light-weight abstract
   264     theory of product types over typedef rather than datatype;
   265 
   266 * HOL: generic code generator for generating executable ML code from
   267 specifications; specific support for HOL constructs such as inductive
   268 datatypes and sets, as well as recursive functions; can be invoked
   269 via 'generate_code' theory section;
   270 
   271 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   272 
   273 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   274 (beware of argument permutation!);
   275 
   276 * HOL: linorder_less_split superseded by linorder_cases;
   277 
   278 * HOL/List: "nodups" renamed to "distinct";
   279 
   280 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   281 to peripheral theory "Hilbert_Choice";
   282 
   283 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   284 in this (rare) case use:
   285 
   286   delSWrapper "split_all_tac"
   287   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   288 
   289 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   290 MAY FAIL;
   291 
   292 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   293 Isabelle's type classes, ^ on functions and relations has too general
   294 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   295 necessary to attach explicit type constraints;
   296 
   297 * HOL/Relation: the prefix name of the infix "O" has been changed from
   298 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   299 renamed accordingly (eg "compI" -> "rel_compI").
   300 
   301 * HOL: syntax translations now work properly with numerals and records
   302 expressions;
   303 
   304 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   305 of "lam" -- INCOMPATIBILITY;
   306 
   307 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   308 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   309 renamed "Product_Type.unit";
   310 
   311 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   312 
   313 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   314 the "cases" method);
   315 
   316 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   317 Florian Kammüller);
   318 
   319 * HOL/IMP: updated and converted to new-style theory format; several
   320 parts turned into readable document, with proper Isar proof texts and
   321 some explanations (by Gerwin Klein);
   322 
   323 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   324 
   325 * HOL-Hyperreal is now a logic image;
   326 
   327 
   328 *** HOLCF ***
   329 
   330 * Isar: consts/constdefs supports mixfix syntax for continuous
   331 operations;
   332 
   333 * Isar: domain package adapted to new-style theory format, e.g. see
   334 HOLCF/ex/Dnat.thy;
   335 
   336 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   337 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   338 lift.induct_tac, always use UU instead of Undef;
   339 
   340 * HOLCF/IMP: updated and converted to new-style theory;
   341 
   342 
   343 *** ZF ***
   344 
   345 * Isar: proper integration of logic-specific tools and packages,
   346 including theory commands '(co)inductive', '(co)datatype',
   347 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   348 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   349 
   350 * theory Main no longer includes AC; for the Axiom of Choice, base
   351 your theory on Main_ZFC;
   352 
   353 * the integer library now covers quotients and remainders, with many
   354 laws relating division to addition, multiplication, etc.;
   355 
   356 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   357 typeless version of the formalism;
   358 
   359 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   360 format;
   361 
   362 * ZF/Induct: new directory for examples of inductive definitions,
   363 including theory Multiset for multiset orderings; converted to
   364 new-style theory format;
   365 
   366 * ZF: many new theorems about lists, ordinals, etc.;
   367 
   368 
   369 *** General ***
   370 
   371 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   372 variable proof controls level of detail: 0 = no proofs (only oracle
   373 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   374 also ref manual for further ML interfaces;
   375 
   376 * Pure/axclass: removed obsolete ML interface
   377 goal_subclass/goal_arity;
   378 
   379 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   380 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   381 separate tokens, so expressions involving minus need to be spaced
   382 properly;
   383 
   384 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   385 rather than "infixl" or "infixr";
   386 
   387 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   388 sort constraint specifications in type inference; e.g. "x::_::foo"
   389 ensures that the type of "x" is of sort "foo" (but not necessarily a
   390 type variable);
   391 
   392 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   393 control output of nested => (types); the default behavior is
   394 "type_brackets";
   395 
   396 * Pure/syntax: builtin parse translation for "_constify" turns valued
   397 tokens into AST constants;
   398 
   399 * Pure/syntax: prefer later declarations of translations and print
   400 translation functions; potential INCOMPATIBILITY: need to reverse
   401 multiple declarations for same syntax element constant;
   402 
   403 * Pure/show_hyps reset by default (in accordance to existing Isar
   404 practice);
   405 
   406 * Provers/classical: renamed addaltern to addafter, addSaltern to
   407 addSafter;
   408 
   409 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   410 as well;
   411 
   412 * system: tested support for MacOS X; should be able to get Isabelle +
   413 Proof General to work in a plain Terminal after installing Poly/ML
   414 (e.g. from the Isabelle distribution area) and GNU bash alone
   415 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   416 support requires further installations, e.g. from
   417 http://fink.sourceforge.net/);
   418 
   419 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   420 
   421 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   422 of 40 MB), cf. ML_OPTIONS;
   423 
   424 * system: Proof General keywords specification is now part of the
   425 Isabelle distribution (see etc/isar-keywords.el);
   426 
   427 * system: support for persistent Proof General sessions (refrain from
   428 outdating all loaded theories on startup); user may create writable
   429 logic images like this: ``isabelle -q HOL Test'';
   430 
   431 * system: smart selection of Isabelle process versus Isabelle
   432 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   433 run both "isabelle" and "Isabelle" even if file names are badly
   434 damaged (executable inspects the case of the first letter of its own
   435 name); added separate "isabelle-process" and "isabelle-interface";
   436 
   437 * system: refrain from any attempt at filtering input streams; no
   438 longer support ``8bit'' encoding of old isabelle font, instead proper
   439 iso-latin characters may now be used; the related isatools
   440 "symbolinput" and "nonascii" have disappeared as well;
   441 
   442 * system: removed old "xterm" interface (the print modes "xterm" and
   443 "xterm_color" are still available for direct use in a suitable
   444 terminal);
   445 
   446 
   447 
   448 New in Isabelle99-2 (February 2001)
   449 -----------------------------------
   450 
   451 *** Overview of INCOMPATIBILITIES ***
   452 
   453 * HOL: please note that theories in the Library and elsewhere often use the
   454 new-style (Isar) format; to refer to their theorems in an ML script you must
   455 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   456 
   457 * HOL: inductive package no longer splits induction rule aggressively,
   458 but only as far as specified by the introductions given; the old
   459 format may be recovered via ML function complete_split_rule or attribute
   460 'split_rule (complete)';
   461 
   462 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   463 gfp_Tarski to gfp_unfold;
   464 
   465 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   466 
   467 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   468 relation); infix "^^" has been renamed "``"; infix "``" has been
   469 renamed "`"; "univalent" has been renamed "single_valued";
   470 
   471 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   472 operation;
   473 
   474 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   475 
   476 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   477 
   478 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   479 consequence, it is no longer monotonic wrt. the local goal context
   480 (which is now passed through the inductive cases);
   481 
   482 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   483 \<gg> to \<ggreater>;
   484 
   485 
   486 *** Document preparation ***
   487 
   488 * \isabellestyle{NAME} selects version of Isabelle output (currently
   489 available: are "it" for near math-mode best-style output, "sl" for
   490 slanted text style, and "tt" for plain type-writer; if no
   491 \isabellestyle command is given, output is according to slanted
   492 type-writer);
   493 
   494 * support sub/super scripts (for single symbols only), input syntax is
   495 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   496 
   497 * some more standard symbols; see Appendix A of the system manual for
   498 the complete list of symbols defined in isabellesym.sty;
   499 
   500 * improved isabelle style files; more abstract symbol implementation
   501 (should now use \isamath{...} and \isatext{...} in custom symbol
   502 definitions);
   503 
   504 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   505 state; Note that presentation of goal states does not conform to
   506 actual human-readable proof documents.  Please do not include goal
   507 states into document output unless you really know what you are doing!
   508 
   509 * proper indentation of antiquoted output with proportional LaTeX
   510 fonts;
   511 
   512 * no_document ML operator temporarily disables LaTeX document
   513 generation;
   514 
   515 * isatool unsymbolize tunes sources for plain ASCII communication;
   516 
   517 
   518 *** Isar ***
   519 
   520 * Pure: Isar now suffers initial goal statements to contain unbound
   521 schematic variables (this does not conform to actual readable proof
   522 documents, due to unpredictable outcome and non-compositional proof
   523 checking); users who know what they are doing may use schematic goals
   524 for Prolog-style synthesis of proven results;
   525 
   526 * Pure: assumption method (an implicit finishing) now handles actual
   527 rules as well;
   528 
   529 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   530 initial goal, declare "that" only as Pure intro (only for single
   531 steps); the "that" rule assumption may now be involved in implicit
   532 finishing, thus ".." becomes a feasible for trivial obtains;
   533 
   534 * Pure: default proof step now includes 'intro_classes'; thus trivial
   535 instance proofs may be performed by "..";
   536 
   537 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   538 statements as well;
   539 
   540 * Pure: more robust selection of calculational rules;
   541 
   542 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   543 rule (as well as the assumption rule);
   544 
   545 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   546 lemmas, using the graph browser tool;
   547 
   548 * Pure: predict failure of "show" in interactive mode;
   549 
   550 * Pure: 'thms_containing' now takes actual terms as arguments;
   551 
   552 * HOL: improved method 'induct' --- now handles non-atomic goals
   553 (potential INCOMPATIBILITY); tuned error handling;
   554 
   555 * HOL: cases and induct rules now provide explicit hints about the
   556 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   557 any remaining facts are inserted into the goal verbatim;
   558 
   559 * HOL: local contexts (aka cases) may now contain term bindings as
   560 well; the 'cases' and 'induct' methods new provide a ?case binding for
   561 the result to be shown in each case;
   562 
   563 * HOL: added 'recdef_tc' command;
   564 
   565 * isatool convert assists in eliminating legacy ML scripts;
   566 
   567 
   568 *** HOL ***
   569 
   570 * HOL/Library: a collection of generic theories to be used together
   571 with main HOL; the theory loader path already includes this directory
   572 by default; the following existing theories have been moved here:
   573 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   574 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   575 
   576 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   577 modelling and verification task performed in Isabelle/HOL +
   578 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   579 
   580 * HOL/Algebra: special summation operator SUM no longer exists, it has
   581 been replaced by setsum; infix 'assoc' now has priority 50 (like
   582 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   583 'domain', this makes the theory consistent with mathematical
   584 literature;
   585 
   586 * HOL basics: added overloaded operations "inverse" and "divide"
   587 (infix "/"), syntax for generic "abs" operation, generic summation
   588 operator \<Sum>;
   589 
   590 * HOL/typedef: simplified package, provide more useful rules (see also
   591 HOL/subset.thy);
   592 
   593 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   594 now expressed as a proper nested rule (old-style tactic scripts may
   595 require atomize_strip_tac to cope with non-atomic premises);
   596 
   597 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   598 to "split_conv" (old name still available for compatibility);
   599 
   600 * HOL: improved concrete syntax for strings (e.g. allows translation
   601 rules with string literals);
   602 
   603 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   604  and Fleuriot's mechanization of analysis, including the transcendental
   605  functions for the reals;
   606 
   607 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   608 
   609 
   610 *** CTT ***
   611 
   612 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   613 "lam" is displayed as TWO lambda-symbols
   614 
   615 * CTT: theory Main now available, containing everything (that is, Bool
   616 and Arith);
   617 
   618 
   619 *** General ***
   620 
   621 * Pure: the Simplifier has been implemented properly as a derived rule
   622 outside of the actual kernel (at last!); the overall performance
   623 penalty in practical applications is about 50%, while reliability of
   624 the Isabelle inference kernel has been greatly improved;
   625 
   626 * print modes "brackets" and "no_brackets" control output of nested =>
   627 (types) and ==> (props); the default behaviour is "brackets";
   628 
   629 * Provers: fast_tac (and friends) now handle actual object-logic rules
   630 as assumptions as well;
   631 
   632 * system: support Poly/ML 4.0;
   633 
   634 * system: isatool install handles KDE version 1 or 2;
   635 
   636 
   637 
   638 New in Isabelle99-1 (October 2000)
   639 ----------------------------------
   640 
   641 *** Overview of INCOMPATIBILITIES ***
   642 
   643 * HOL: simplification of natural numbers is much changed; to partly
   644 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   645 issue the following ML commands:
   646 
   647   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   648   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   649 
   650 * HOL: simplification no longer dives into case-expressions; this is
   651 controlled by "t.weak_case_cong" for each datatype t;
   652 
   653 * HOL: nat_less_induct renamed to less_induct;
   654 
   655 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   656 fixsome to patch .thy and .ML sources automatically;
   657 
   658   select_equality  -> some_equality
   659   select_eq_Ex     -> some_eq_ex
   660   selectI2EX       -> someI2_ex
   661   selectI2         -> someI2
   662   selectI          -> someI
   663   select1_equality -> some1_equality
   664   Eps_sym_eq       -> some_sym_eq_trivial
   665   Eps_eq           -> some_eq_trivial
   666 
   667 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   668 
   669 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   670 instead);
   671 
   672 * HOL: the recursion equations generated by 'recdef' are now called
   673 f.simps instead of f.rules;
   674 
   675 * HOL: qed_spec_mp now also handles bounded ALL as well;
   676 
   677 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   678 sometimes be needed;
   679 
   680 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   681 
   682 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   683 
   684 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   685 product is now "<*>" instead of "Times"; the lexicographic product is
   686 now "<*lex*>" instead of "**";
   687 
   688 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   689 of main HOL, but was unused); better use HOL's datatype package;
   690 
   691 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   692 the old syntax may be recovered as follows:
   693 
   694   syntax (symbols)
   695     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   696       (infixl "\\<oplus>" 100)
   697 
   698 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   699 
   700 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   701 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   702 internally;
   703 
   704 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   705 changed from A/r to A//r;
   706 
   707 * ZF: new treatment of arithmetic (nat & int) may break some old
   708 proofs;
   709 
   710 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   711 rulify -> rule_format, elimify -> elim_format, ...);
   712 
   713 * Isar/Provers: intro/elim/dest attributes changed; renamed
   714 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   715 should have to change intro!! to intro? only); replaced "delrule" by
   716 "rule del";
   717 
   718 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   719 
   720 * Provers: strengthened force_tac by using new first_best_tac;
   721 
   722 * LaTeX document preparation: several changes of isabelle.sty (see
   723 lib/texinputs);
   724 
   725 
   726 *** Document preparation ***
   727 
   728 * formal comments (text blocks etc.) in new-style theories may now
   729 contain antiquotations of thm/prop/term/typ/text to be presented
   730 according to latex print mode; concrete syntax is like this:
   731 @{term[show_types] "f(x) = a + x"};
   732 
   733 * isatool mkdir provides easy setup of Isabelle session directories,
   734 including proper document sources;
   735 
   736 * generated LaTeX sources are now deleted after successful run
   737 (isatool document -c); may retain a copy somewhere else via -D option
   738 of isatool usedir;
   739 
   740 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   741 style files, achieving self-contained LaTeX sources and simplifying
   742 LaTeX debugging;
   743 
   744 * old-style theories now produce (crude) LaTeX output as well;
   745 
   746 * browser info session directories are now self-contained (may be put
   747 on WWW server seperately); improved graphs of nested sessions; removed
   748 graph for 'all sessions';
   749 
   750 * several improvements in isabelle style files; \isabellestyle{it}
   751 produces fake math mode output; \isamarkupheader is now \section by
   752 default; see lib/texinputs/isabelle.sty etc.;
   753 
   754 
   755 *** Isar ***
   756 
   757 * Isar/Pure: local results and corresponding term bindings are now
   758 subject to Hindley-Milner polymorphism (similar to ML); this
   759 accommodates incremental type-inference very nicely;
   760 
   761 * Isar/Pure: new derived language element 'obtain' supports
   762 generalized existence reasoning;
   763 
   764 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   765 support accumulation of results, without applying any rules yet;
   766 useful to collect intermediate results without explicit name
   767 references, and for use with transitivity rules with more than 2
   768 premises;
   769 
   770 * Isar/Pure: scalable support for case-analysis type proofs: new
   771 'case' language element refers to local contexts symbolically, as
   772 produced by certain proof methods; internally, case names are attached
   773 to theorems as "tags";
   774 
   775 * Isar/Pure: theory command 'hide' removes declarations from
   776 class/type/const name spaces;
   777 
   778 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   779 indicate potential overloading;
   780 
   781 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   782 
   783 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   784 "{a,b,c}" instead of {a,b,c};
   785 
   786 * Isar/Pure now provides its own version of intro/elim/dest
   787 attributes; useful for building new logics, but beware of confusion
   788 with the version in Provers/classical;
   789 
   790 * Isar/Pure: the local context of (non-atomic) goals is provided via
   791 case name 'antecedent';
   792 
   793 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   794 to the current context is now done automatically);
   795 
   796 * Isar/Pure: theory command 'method_setup' provides a simple interface
   797 for definining proof methods in ML;
   798 
   799 * Isar/Provers: intro/elim/dest attributes changed; renamed
   800 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   801 most cases, one should have to change intro!! to intro? only);
   802 replaced "delrule" by "rule del";
   803 
   804 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   805 'symmetric' attribute (the latter supercedes [RS sym]);
   806 
   807 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   808 method modifier); 'simp' method: 'only:' modifier removes loopers as
   809 well (including splits);
   810 
   811 * Isar/Provers: Simplifier and Classical methods now support all kind
   812 of modifiers used in the past, including 'cong', 'iff', etc.
   813 
   814 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   815 of Simplifier and Classical reasoner);
   816 
   817 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   818 now support named cases; major packages (inductive, datatype, primrec,
   819 recdef) support case names and properly name parameters;
   820 
   821 * Isar/HOL: new transitivity rules for substitution in inequalities --
   822 monotonicity conditions are extracted to be proven at end of
   823 calculations;
   824 
   825 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   826 method anyway;
   827 
   828 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   829 split_if split_if_asm; datatype package provides theorems foo.splits =
   830 foo.split foo.split_asm for each datatype;
   831 
   832 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   833 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   834 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   835 use "(cases (simplified))" method in proper proof texts);
   836 
   837 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   838 
   839 * Isar: names of theorems etc. may be natural numbers as well;
   840 
   841 * Isar: 'pr' command: optional arguments for goals_limit and
   842 ProofContext.prems_limit; no longer prints theory contexts, but only
   843 proof states;
   844 
   845 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   846 additional print modes to be specified; e.g. "pr(latex)" will print
   847 proof state according to the Isabelle LaTeX style;
   848 
   849 * Isar: improved support for emulating tactic scripts, including proof
   850 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   851 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   852 (for HOL datatypes);
   853 
   854 * Isar: simplified (more robust) goal selection of proof methods: 1st
   855 goal, all goals, or explicit goal specifier (tactic emulation); thus
   856 'proof method scripts' have to be in depth-first order;
   857 
   858 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   859 
   860 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   861 should instead use individual commands for printing items
   862 (print_commands, print_methods etc.);
   863 
   864 * Isar: added 'nothing' --- the empty list of theorems;
   865 
   866 
   867 *** HOL ***
   868 
   869 * HOL/MicroJava: formalization of a fragment of Java, together with a
   870 corresponding virtual machine and a specification of its bytecode
   871 verifier and a lightweight bytecode verifier, including proofs of
   872 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   873 Cornelia Pusch (see also the homepage of project Bali at
   874 http://isabelle.in.tum.de/Bali/);
   875 
   876 * HOL/Algebra: new theory of rings and univariate polynomials, by
   877 Clemens Ballarin;
   878 
   879 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   880 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   881 Rasmussen;
   882 
   883 * HOL/Lattice: fundamental concepts of lattice theory and order
   884 structures, including duals, properties of bounds versus algebraic
   885 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   886 Theorem for complete lattices etc.; may also serve as a demonstration
   887 for abstract algebraic reasoning using axiomatic type classes, and
   888 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   889 
   890 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   891 von Oheimb;
   892 
   893 * HOL/IMPP: extension of IMP with local variables and mutually
   894 recursive procedures, by David von Oheimb;
   895 
   896 * HOL/Lambda: converted into new-style theory and document;
   897 
   898 * HOL/ex/Multiquote: example of multiple nested quotations and
   899 anti-quotations -- basically a generalized version of de-Bruijn
   900 representation; very useful in avoiding lifting of operations;
   901 
   902 * HOL/record: added general record equality rule to simpset; fixed
   903 select-update simplification procedure to handle extended records as
   904 well; admit "r" as field name;
   905 
   906 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   907 other numeric types and also as the identity of groups, rings, etc.;
   908 
   909 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   910 Types nat and int belong to this axclass;
   911 
   912 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   913    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   914    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   915   two terms #m*u and #n*u are replaced by #(m+n)*u
   916     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   917   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   918     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   919 
   920 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   921 powerful prover for predicate logic but knows nothing of clasets; see
   922 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   923 
   924 * HOL: new version of "case_tac" subsumes both boolean case split and
   925 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   926 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   927 
   928 * HOL: simplification no longer dives into case-expressions: only the
   929 selector expression is simplified, but not the remaining arms; to
   930 enable full simplification of case-expressions for datatype t, you may
   931 remove t.weak_case_cong from the simpset, either globally (Delcongs
   932 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   933 
   934 * HOL/recdef: the recursion equations generated by 'recdef' for
   935 function 'f' are now called f.simps instead of f.rules; if all
   936 termination conditions are proved automatically, these simplification
   937 rules are added to the simpset, as in primrec; rules may be named
   938 individually as well, resulting in a separate list of theorems for
   939 each equation;
   940 
   941 * HOL/While is a new theory that provides a while-combinator. It
   942 permits the definition of tail-recursive functions without the
   943 provision of a termination measure. The latter is necessary once the
   944 invariant proof rule for while is applied.
   945 
   946 * HOL: new (overloaded) notation for the set of elements below/above
   947 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   948 
   949 * HOL: theorems impI, allI, ballI bound as "strip";
   950 
   951 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   952 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   953 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   954 
   955 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   956 
   957 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   958 main HOL, but was unused);
   959 
   960 * HOL: fewer consts declared as global (e.g. have to refer to
   961 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   962 
   963 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   964 in case of overlap with user translations (e.g. judgements over
   965 tuples); (note that the underlying logical represenation is still
   966 bogus);
   967 
   968 
   969 *** ZF ***
   970 
   971 * ZF: simplification automatically cancels common terms in arithmetic
   972 expressions over nat and int;
   973 
   974 * ZF: new treatment of nat to minimize type-checking: all operators
   975 coerce their operands to a natural number using the function natify,
   976 making the algebraic laws unconditional;
   977 
   978 * ZF: as above, for int: operators coerce their operands to an integer
   979 using the function intify;
   980 
   981 * ZF: the integer library now contains many of the usual laws for the
   982 orderings, including $<=, and monotonicity laws for $+ and $*;
   983 
   984 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   985 simplification;
   986 
   987 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   988 to the simplifier and classical reasoner simultaneously;
   989 
   990 
   991 *** General ***
   992 
   993 * Provers: blast_tac now handles actual object-logic rules as
   994 assumptions; note that auto_tac uses blast_tac internally as well;
   995 
   996 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   997 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   998 
   999 * Provers: delrules now handles destruct rules as well (no longer need
  1000 explicit make_elim);
  1001 
  1002 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1003   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1004 use instead the strong form,
  1005   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1006 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1007 from destruct-rules;
  1008 
  1009 * Provers: Simplifier.easy_setup provides a fast path to basic
  1010 Simplifier setup for new object-logics;
  1011 
  1012 * Pure: AST translation rules no longer require constant head on LHS;
  1013 
  1014 * Pure: improved name spaces: ambiguous output is qualified; support
  1015 for hiding of names;
  1016 
  1017 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1018 XSYMBOL_HOME; no longer need to do manual configuration in most
  1019 situations;
  1020 
  1021 * system: compression of ML heaps images may now be controlled via -c
  1022 option of isabelle and isatool usedir (currently only observed by
  1023 Poly/ML);
  1024 
  1025 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1026 useful for remote X11);
  1027 
  1028 * system: provide TAGS file for Isabelle sources;
  1029 
  1030 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1031 order;
  1032 
  1033 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1034 timing flag supersedes proof_timing and Toplevel.trace;
  1035 
  1036 * ML: new combinators |>> and |>>> for incremental transformations
  1037 with secondary results (e.g. certain theory extensions):
  1038 
  1039 * ML: PureThy.add_defs gets additional argument to indicate potential
  1040 overloading (usually false);
  1041 
  1042 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1043 results;
  1044 
  1045 
  1046 
  1047 New in Isabelle99 (October 1999)
  1048 --------------------------------
  1049 
  1050 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1051 
  1052 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1053 are no longer simplified.  (This allows the simplifier to unfold recursive
  1054 functional programs.)  To restore the old behaviour, declare
  1055 
  1056     Delcongs [if_weak_cong];
  1057 
  1058 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1059 complement;
  1060 
  1061 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1062 
  1063 * HOL/datatype: mutual_induct_tac no longer exists --
  1064   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1065 
  1066 * HOL/typedef: fixed type inference for representing set; type
  1067 arguments now have to occur explicitly on the rhs as type constraints;
  1068 
  1069 * ZF: The con_defs part of an inductive definition may no longer refer
  1070 to constants declared in the same theory;
  1071 
  1072 * HOL, ZF: the function mk_cases, generated by the inductive
  1073 definition package, has lost an argument.  To simplify its result, it
  1074 uses the default simpset instead of a supplied list of theorems.
  1075 
  1076 * HOL/List: the constructors of type list are now Nil and Cons;
  1077 
  1078 * Simplifier: the type of the infix ML functions
  1079         setSSolver addSSolver setSolver addSolver
  1080 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1081 for packaging solvers. A solver is created via
  1082         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1083 where the string argument is only a comment.
  1084 
  1085 
  1086 *** Proof tools ***
  1087 
  1088 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1089 decision procedure for linear arithmetic. Currently it is used for
  1090 types `nat', `int', and `real' in HOL (see below); it can, should and
  1091 will be instantiated for other types and logics as well.
  1092 
  1093 * The simplifier now accepts rewrite rules with flexible heads, eg
  1094      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1095   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1096   matching.
  1097 
  1098 
  1099 *** General ***
  1100 
  1101 * New Isabelle/Isar subsystem provides an alternative to traditional
  1102 tactical theorem proving; together with the ProofGeneral/isar user
  1103 interface it offers an interactive environment for developing human
  1104 readable proof documents (Isar == Intelligible semi-automated
  1105 reasoning); for further information see isatool doc isar-ref,
  1106 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1107 
  1108 * improved and simplified presentation of theories: better HTML markup
  1109 (including colors), graph views in several sizes; isatool usedir now
  1110 provides a proper interface for user theories (via -P option); actual
  1111 document preparation based on (PDF)LaTeX is available as well (for
  1112 new-style theories only); see isatool doc system for more information;
  1113 
  1114 * native support for Proof General, both for classic Isabelle and
  1115 Isabelle/Isar;
  1116 
  1117 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1118 using the graph browser tool;
  1119 
  1120 * Isabelle manuals now also available as PDF;
  1121 
  1122 * theory loader rewritten from scratch (may not be fully
  1123 bug-compatible); old loadpath variable has been replaced by show_path,
  1124 add_path, del_path, reset_path functions; new operations such as
  1125 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1126 isatool doc ref);
  1127 
  1128 * improved isatool install: option -k creates KDE application icon,
  1129 option -p DIR installs standalone binaries;
  1130 
  1131 * added ML_PLATFORM setting (useful for cross-platform installations);
  1132 more robust handling of platform specific ML images for SML/NJ;
  1133 
  1134 * the settings environment is now statically scoped, i.e. it is never
  1135 created again in sub-processes invoked from isabelle, isatool, or
  1136 Isabelle;
  1137 
  1138 * path element specification '~~' refers to '$ISABELLE_HOME';
  1139 
  1140 * in locales, the "assumes" and "defines" parts may be omitted if
  1141 empty;
  1142 
  1143 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1144 long arrows);
  1145 
  1146 * new print_mode "HTML";
  1147 
  1148 * new flag show_tags controls display of tags of theorems (which are
  1149 basically just comments that may be attached by some tools);
  1150 
  1151 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1152 mode and goal output format:
  1153 
  1154 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1155 244c244
  1156 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1157 ---
  1158 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1159 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1160 181c181
  1161 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1162 ---
  1163 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1164 
  1165 * function bind_thms stores lists of theorems (cf. bind_thm);
  1166 
  1167 * new shorthand tactics ftac, eatac, datac, fatac;
  1168 
  1169 * qed (and friends) now accept "" as result name; in that case the
  1170 theorem is not stored, but proper checks and presentation of the
  1171 result still apply;
  1172 
  1173 * theorem database now also indexes constants "Trueprop", "all",
  1174 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1175 
  1176 
  1177 *** HOL ***
  1178 
  1179 ** HOL arithmetic **
  1180 
  1181 * There are now decision procedures for linear arithmetic over nat and
  1182 int:
  1183 
  1184 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1185 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1186 are treated as atomic; subformulae not involving type `nat' or `int'
  1187 are ignored; quantified subformulae are ignored unless they are
  1188 positive universal or negative existential. The tactic has to be
  1189 invoked by hand and can be a little bit slow. In particular, the
  1190 running time is exponential in the number of occurrences of `min' and
  1191 `max', and `-' on `nat'.
  1192 
  1193 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1194 (negated) (in)equalities among the premises and the conclusion into
  1195 account (i.e. no compound formulae) and does not know about `min' and
  1196 `max', and `-' on `nat'. It is fast and is used automatically by the
  1197 simplifier.
  1198 
  1199 NB: At the moment, these decision procedures do not cope with mixed
  1200 nat/int formulae where the two parts interact, such as `m < n ==>
  1201 int(m) < int(n)'.
  1202 
  1203 * HOL/Numeral provides a generic theory of numerals (encoded
  1204 efficiently as bit strings); setup for types nat/int/real is in place;
  1205 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1206 int, existing theories and proof scripts may require a few additional
  1207 type constraints;
  1208 
  1209 * integer division and remainder can now be performed on constant
  1210 arguments;
  1211 
  1212 * many properties of integer multiplication, division and remainder
  1213 are now available;
  1214 
  1215 * An interface to the Stanford Validity Checker (SVC) is available through the
  1216 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1217 are proved automatically.  SVC must be installed separately, and its results
  1218 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1219 invocation of the underlying oracle).  For SVC see
  1220   http://verify.stanford.edu/SVC
  1221 
  1222 * IsaMakefile: the HOL-Real target now builds an actual image;
  1223 
  1224 
  1225 ** HOL misc **
  1226 
  1227 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1228 (in Isabelle/Isar) -- by Gertrud Bauer;
  1229 
  1230 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1231 analysis for assembly languages with subtypes;
  1232 
  1233 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1234 -- avoids syntactic ambiguities and treats state, transition, and
  1235 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1236 changed syntax and (many) tactics;
  1237 
  1238 * HOL/inductive: Now also handles more general introduction rules such
  1239   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1240   theorems are now maintained within the theory (maintained via the
  1241   "mono" attribute);
  1242 
  1243 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1244   (using function types) such as
  1245 
  1246   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1247 
  1248 * HOL/record: record_simproc (part of the default simpset) takes care
  1249 of selectors applied to updated records; record_split_tac is no longer
  1250 part of the default claset; update_defs may now be removed from the
  1251 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1252 
  1253   claset_ref () := claset() addSWrapper record_split_wrapper;
  1254   Delsimprocs [record_simproc]
  1255 
  1256 * HOL/typedef: fixed type inference for representing set; type
  1257 arguments now have to occur explicitly on the rhs as type constraints;
  1258 
  1259 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1260 names rather than an ML expression;
  1261 
  1262 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1263 supplied later.  Program schemes can be defined, such as
  1264     "While B C s = (if B s then While B C (C s) else s)"
  1265 where the well-founded relation can be chosen after B and C have been given.
  1266 
  1267 * HOL/List: the constructors of type list are now Nil and Cons;
  1268 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1269 course, ML tools referring to List.list.op # etc. have to be adapted;
  1270 
  1271 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1272 disabled by default; run isabelle with option -m HOL to get back to
  1273 the original Gordon/HOL-style output;
  1274 
  1275 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1276 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1277 
  1278 * HOL basic syntax simplified (more orthogonal): all variants of
  1279 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1280 Eps operator is provided as well: "SOME x. P[x]";
  1281 
  1282 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1283 
  1284 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1285 thus available for user theories;
  1286 
  1287 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1288 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1289 time;
  1290 
  1291 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1292 several times and then mp;
  1293 
  1294 
  1295 *** LK ***
  1296 
  1297 * the notation <<...>> is now available as a notation for sequences of
  1298 formulas;
  1299 
  1300 * the simplifier is now installed
  1301 
  1302 * the axiom system has been generalized (thanks to Soren Heilmann)
  1303 
  1304 * the classical reasoner now has a default rule database
  1305 
  1306 
  1307 *** ZF ***
  1308 
  1309 * new primrec section allows primitive recursive functions to be given
  1310 directly (as in HOL) over datatypes and the natural numbers;
  1311 
  1312 * new tactics induct_tac and exhaust_tac for induction (or case
  1313 analysis) over datatypes and the natural numbers;
  1314 
  1315 * the datatype declaration of type T now defines the recursor T_rec;
  1316 
  1317 * simplification automatically does freeness reasoning for datatype
  1318 constructors;
  1319 
  1320 * automatic type-inference, with AddTCs command to insert new
  1321 type-checking rules;
  1322 
  1323 * datatype introduction rules are now added as Safe Introduction rules
  1324 to the claset;
  1325 
  1326 * the syntax "if P then x else y" is now available in addition to
  1327 if(P,x,y);
  1328 
  1329 
  1330 *** Internal programming interfaces ***
  1331 
  1332 * tuned simplifier trace output; new flag debug_simp;
  1333 
  1334 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1335 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1336 
  1337 * AxClass.axclass_tac lost the theory argument;
  1338 
  1339 * tuned current_goals_markers semantics: begin / end goal avoids
  1340 printing empty lines;
  1341 
  1342 * removed prs and prs_fn hook, which was broken because it did not
  1343 include \n in its semantics, forcing writeln to add one
  1344 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1345 string -> unit if you really want to output text without newline;
  1346 
  1347 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1348 plain output, interface builders may have to enable 'isabelle_font'
  1349 mode to get Isabelle font glyphs as before;
  1350 
  1351 * refined token_translation interface; INCOMPATIBILITY: output length
  1352 now of type real instead of int;
  1353 
  1354 * theory loader actions may be traced via new ThyInfo.add_hook
  1355 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1356 your own database of information attached to *whole* theories -- as
  1357 opposed to intra-theory data slots offered via TheoryDataFun;
  1358 
  1359 * proper handling of dangling sort hypotheses (at last!);
  1360 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1361 extra sort hypotheses that can be witnessed from the type signature;
  1362 the force_strip_shyps flag is gone, any remaining shyps are simply
  1363 left in the theorem (with a warning issued by strip_shyps_warning);
  1364 
  1365 
  1366 
  1367 New in Isabelle98-1 (October 1998)
  1368 ----------------------------------
  1369 
  1370 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1371 
  1372 * several changes of automated proof tools;
  1373 
  1374 * HOL: major changes to the inductive and datatype packages, including
  1375 some minor incompatibilities of theory syntax;
  1376 
  1377 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1378 called `inj_on';
  1379 
  1380 * HOL: removed duplicate thms in Arith:
  1381   less_imp_add_less  should be replaced by  trans_less_add1
  1382   le_imp_add_le      should be replaced by  trans_le_add1
  1383 
  1384 * HOL: unary minus is now overloaded (new type constraints may be
  1385 required);
  1386 
  1387 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1388 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1389 now taken as an integer constant.
  1390 
  1391 * Pure: ML function 'theory_of' renamed to 'theory';
  1392 
  1393 
  1394 *** Proof tools ***
  1395 
  1396 * Simplifier:
  1397   1. Asm_full_simp_tac is now more aggressive.
  1398      1. It will sometimes reorient premises if that increases their power to
  1399         simplify.
  1400      2. It does no longer proceed strictly from left to right but may also
  1401         rotate premises to achieve further simplification.
  1402      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1403      old Asm_full_simp_tac in that it does not rotate premises.
  1404   2. The simplifier now knows a little bit about nat-arithmetic.
  1405 
  1406 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1407 allows for selected deletion of wrappers, by introduction of names for
  1408 wrapper functionals.  This implies that addbefore, addSbefore,
  1409 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1410 and that adding two tactics with the same name overwrites the first
  1411 one (emitting a warning).
  1412   type wrapper = (int -> tactic) -> (int -> tactic)
  1413   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1414   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1415   delWrapper, delSWrapper: claset *  string            -> claset
  1416   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1417 
  1418 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1419 semantics; addbefore now affects only the unsafe part of step_tac
  1420 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1421 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1422 by Force_tac;
  1423 
  1424 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1425 compWrapper; added safe wrapper (and access functions for it);
  1426 
  1427 * HOL/split_all_tac is now much faster and fails if there is nothing
  1428 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1429 and the names of the automatically generated variables have changed.
  1430 split_all_tac has moved within claset() from unsafe wrappers to safe
  1431 wrappers, which means that !!-bound variables are split much more
  1432 aggressively, and safe_tac and clarify_tac now split such variables.
  1433 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1434 Note: the same holds for record_split_tac, which does the job of
  1435 split_all_tac for record fields.
  1436 
  1437 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1438 permanently to the default simpset using Addsplits just like
  1439 Addsimps. They can be removed via Delsplits just like
  1440 Delsimps. Lower-case versions are also available.
  1441 
  1442 * HOL/Simplifier: The rule split_if is now part of the default
  1443 simpset. This means that the simplifier will eliminate all occurrences
  1444 of if-then-else in the conclusion of a goal. To prevent this, you can
  1445 either remove split_if completely from the default simpset by
  1446 `Delsplits [split_if]' or remove it in a specific call of the
  1447 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1448 other case splitting rules to/from the default simpset: every datatype
  1449 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1450 t is the name of the datatype).
  1451 
  1452 * Classical reasoner / Simplifier combination: new force_tac (and
  1453 derivatives Force_tac, force) combines rewriting and classical
  1454 reasoning (and whatever other tools) similarly to auto_tac, but is
  1455 aimed to solve the given subgoal completely.
  1456 
  1457 
  1458 *** General ***
  1459 
  1460 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1461 and `goalw': the theory is no longer needed as an explicit argument -
  1462 the current theory context is used; assumptions are no longer returned
  1463 at the ML-level unless one of them starts with ==> or !!; it is
  1464 recommended to convert to these new commands using isatool fixgoal
  1465 (backup your sources first!);
  1466 
  1467 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1468 the current theory context, and 'theory' to lookup stored theories;
  1469 
  1470 * new theory section 'locale' for declaring constants, assumptions and
  1471 definitions that have local scope;
  1472 
  1473 * new theory section 'nonterminals' for purely syntactic types;
  1474 
  1475 * new theory section 'setup' for generic ML setup functions
  1476 (e.g. package initialization);
  1477 
  1478 * the distribution now includes Isabelle icons: see
  1479 lib/logo/isabelle-{small,tiny}.xpm;
  1480 
  1481 * isatool install - install binaries with absolute references to
  1482 ISABELLE_HOME/bin;
  1483 
  1484 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1485 
  1486 * print mode 'emacs' reserved for Isamode;
  1487 
  1488 * support multiple print (ast) translations per constant name;
  1489 
  1490 * theorems involving oracles are now printed with a suffixed [!];
  1491 
  1492 
  1493 *** HOL ***
  1494 
  1495 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1496 
  1497 * HOL/inductive package reorganized and improved: now supports mutual
  1498 definitions such as
  1499 
  1500   inductive EVEN ODD
  1501     intrs
  1502       null "0 : EVEN"
  1503       oddI "n : EVEN ==> Suc n : ODD"
  1504       evenI "n : ODD ==> Suc n : EVEN"
  1505 
  1506 new theorem list "elims" contains an elimination rule for each of the
  1507 recursive sets; inductive definitions now handle disjunctive premises
  1508 correctly (also ZF);
  1509 
  1510 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1511 "mutual_induct" no longer exists - the induction rule is always
  1512 contained in "induct";
  1513 
  1514 
  1515 * HOL/datatype package re-implemented and greatly improved: now
  1516 supports mutually recursive datatypes such as
  1517 
  1518   datatype
  1519     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1520             | SUM ('a aexp) ('a aexp)
  1521             | DIFF ('a aexp) ('a aexp)
  1522             | NUM 'a
  1523   and
  1524     'a bexp = LESS ('a aexp) ('a aexp)
  1525             | AND ('a bexp) ('a bexp)
  1526             | OR ('a bexp) ('a bexp)
  1527 
  1528 as well as indirectly recursive datatypes such as
  1529 
  1530   datatype
  1531     ('a, 'b) term = Var 'a
  1532                   | App 'b ((('a, 'b) term) list)
  1533 
  1534 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1535 induction on mutually / indirectly recursive datatypes.
  1536 
  1537 Primrec equations are now stored in theory and can be accessed via
  1538 <function_name>.simps.
  1539 
  1540 INCOMPATIBILITIES:
  1541 
  1542   - Theories using datatypes must now have theory Datatype as an
  1543     ancestor.
  1544   - The specific <typename>.induct_tac no longer exists - use the
  1545     generic induct_tac instead.
  1546   - natE has been renamed to nat.exhaust - use exhaust_tac
  1547     instead of res_inst_tac ... natE. Note that the variable
  1548     names in nat.exhaust differ from the names in natE, this
  1549     may cause some "fragile" proofs to fail.
  1550   - The theorems split_<typename>_case and split_<typename>_case_asm
  1551     have been renamed to <typename>.split and <typename>.split_asm.
  1552   - Since default sorts of type variables are now handled correctly,
  1553     some datatype definitions may have to be annotated with explicit
  1554     sort constraints.
  1555   - Primrec definitions no longer require function name and type
  1556     of recursive argument.
  1557 
  1558 Consider using isatool fixdatatype to adapt your theories and proof
  1559 scripts to the new package (backup your sources first!).
  1560 
  1561 
  1562 * HOL/record package: considerably improved implementation; now
  1563 includes concrete syntax for record types, terms, updates; theorems
  1564 for surjective pairing and splitting !!-bound record variables; proof
  1565 support is as follows:
  1566 
  1567   1) standard conversions (selectors or updates applied to record
  1568 constructor terms) are part of the standard simpset;
  1569 
  1570   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1571 made part of standard simpset and claset via addIffs;
  1572 
  1573   3) a tactic for record field splitting (record_split_tac) is part of
  1574 the standard claset (addSWrapper);
  1575 
  1576 To get a better idea about these rules you may retrieve them via
  1577 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1578 the name of your record type.
  1579 
  1580 The split tactic 3) conceptually simplifies by the following rule:
  1581 
  1582   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1583 
  1584 Thus any record variable that is bound by meta-all will automatically
  1585 blow up into some record constructor term, consequently the
  1586 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1587 solve record problems automatically.
  1588 
  1589 
  1590 * reorganized the main HOL image: HOL/Integ and String loaded by
  1591 default; theory Main includes everything;
  1592 
  1593 * automatic simplification of integer sums and comparisons, using cancellation;
  1594 
  1595 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1596 
  1597 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1598 
  1599 * many new identities for unions, intersections, set difference, etc.;
  1600 
  1601 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1602 called split_if, split_split, split_sum_case and split_nat_case (to go
  1603 with add/delsplits);
  1604 
  1605 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1606 (?x::unit) = (); this is made part of the default simpset, which COULD
  1607 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1608 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1609 unit_abs_eta_conv is added in order to counter the effect of
  1610 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1611 %u.f();
  1612 
  1613 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1614 makes more sense);
  1615 
  1616 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1617   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1618   disjointness reasoning but breaking a few old proofs.
  1619 
  1620 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1621 to 'converse' from 'inverse' (for compatibility with ZF and some
  1622 literature);
  1623 
  1624 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1625 the well-founded relation;
  1626 
  1627 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1628     Compl A.  The "Compl" syntax remains available as input syntax for this
  1629     release ONLY.
  1630 
  1631 * HOL/Update: new theory of function updates:
  1632     f(a:=b) == %x. if x=a then b else f x
  1633 may also be iterated as in f(a:=b,c:=d,...);
  1634 
  1635 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1636 
  1637 * HOL/List:
  1638   - new function list_update written xs[i:=v] that updates the i-th
  1639     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1640   - new function `upt' written [i..j(] which generates the list
  1641     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1642     bound write [i..j], which is a shorthand for [i..j+1(].
  1643   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1644 
  1645 * HOL/Arith:
  1646   - removed 'pred' (predecessor) function;
  1647   - generalized some theorems about n-1;
  1648   - many new laws about "div" and "mod";
  1649   - new laws about greatest common divisors (see theory ex/Primes);
  1650 
  1651 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1652 instead of "inverse";
  1653 
  1654 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1655   of the multiset ordering;
  1656 
  1657 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1658   (not included by default);
  1659 
  1660 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1661 
  1662 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1663   programs, i.e. different program variables may have different types.
  1664 
  1665 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1666   [previously, this check worked only if the rewrite rule was unconditional]
  1667   Now rew can involve either definitions or equalities (either == or =).
  1668 
  1669 
  1670 *** ZF ***
  1671 
  1672 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1673   only the theorems proved on ZF.ML;
  1674 
  1675 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1676   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1677   disjointness reasoning but breaking a few old proofs.
  1678 
  1679 * ZF/Update: new theory of function updates
  1680     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1681   may also be iterated as in f(a:=b,c:=d,...);
  1682 
  1683 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1684 
  1685 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1686   [previously, this check worked only if the rewrite rule was unconditional]
  1687   Now rew can involve either definitions or equalities (either == or =).
  1688 
  1689 * case_tac provided for compatibility with HOL
  1690     (like the old excluded_middle_tac, but with subgoals swapped)
  1691 
  1692 
  1693 *** Internal programming interfaces ***
  1694 
  1695 * Pure: several new basic modules made available for general use, see
  1696 also src/Pure/README;
  1697 
  1698 * improved the theory data mechanism to support encapsulation (data
  1699 kind name replaced by private Object.kind, acting as authorization
  1700 key); new type-safe user interface via functor TheoryDataFun; generic
  1701 print_data function becomes basically useless;
  1702 
  1703 * removed global_names compatibility flag -- all theory declarations
  1704 are qualified by default;
  1705 
  1706 * module Pure/Syntax now offers quote / antiquote translation
  1707 functions (useful for Hoare logic etc. with implicit dependencies);
  1708 see HOL/ex/Antiquote for an example use;
  1709 
  1710 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1711 cterm -> thm;
  1712 
  1713 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1714 subgoal;
  1715 
  1716 * Display.print_goals function moved to Locale.print_goals;
  1717 
  1718 * standard print function for goals supports current_goals_markers
  1719 variable for marking begin of proof, end of proof, start of goal; the
  1720 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1721 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1722 for example;
  1723 
  1724 
  1725 
  1726 New in Isabelle98 (January 1998)
  1727 --------------------------------
  1728 
  1729 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1730 
  1731 * changed lexical syntax of terms / types: dots made part of long
  1732 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1733 
  1734 * simpset (and claset) reference variable replaced by functions
  1735 simpset / simpset_ref;
  1736 
  1737 * no longer supports theory aliases (via merge) and non-trivial
  1738 implicit merge of thms' signatures;
  1739 
  1740 * most internal names of constants changed due to qualified names;
  1741 
  1742 * changed Pure/Sequence interface (see Pure/seq.ML);
  1743 
  1744 
  1745 *** General Changes ***
  1746 
  1747 * hierachically structured name spaces (for consts, types, axms, thms
  1748 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1749 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1750 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1751 long_names for fully qualified output names; NOTE: ML programs
  1752 (special tactics, packages etc.) referring to internal names may have
  1753 to be adapted to cope with fully qualified names; in case of severe
  1754 backward campatibility problems try setting 'global_names' at compile
  1755 time to have enrything declared within a flat name space; one may also
  1756 fine tune name declarations in theories via the 'global' and 'local'
  1757 section;
  1758 
  1759 * reimplemented the implicit simpset and claset using the new anytype
  1760 data filed in signatures; references simpset:simpset ref etc. are
  1761 replaced by functions simpset:unit->simpset and
  1762 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1763 to patch your ML files accordingly;
  1764 
  1765 * HTML output now includes theory graph data for display with Java
  1766 applet or isatool browser; data generated automatically via isatool
  1767 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1768 
  1769 * defs may now be conditional; improved rewrite_goals_tac to handle
  1770 conditional equations;
  1771 
  1772 * defs now admits additional type arguments, using TYPE('a) syntax;
  1773 
  1774 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1775 creates a new theory node; implicit merge of thms' signatures is
  1776 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1777 transfer:theory->thm->thm in (rare) cases;
  1778 
  1779 * improved handling of draft signatures / theories; draft thms (and
  1780 ctyps, cterms) are automatically promoted to real ones;
  1781 
  1782 * slightly changed interfaces for oracles: admit many per theory, named
  1783 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1784 
  1785 * print_goals: optional output of const types (set show_consts and
  1786 show_types);
  1787 
  1788 * improved output of warnings (###) and errors (***);
  1789 
  1790 * subgoal_tac displays a warning if the new subgoal has type variables;
  1791 
  1792 * removed old README and Makefiles;
  1793 
  1794 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1795 
  1796 * removed obsolete init_pps and init_database;
  1797 
  1798 * deleted the obsolete tactical STATE, which was declared by
  1799     fun STATE tacfun st = tacfun st st;
  1800 
  1801 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1802 (which abbreviates $HOME);
  1803 
  1804 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1805 use isatool fixseq to adapt your ML programs (this works for fully
  1806 qualified references to the Sequence structure only!);
  1807 
  1808 * use_thy no longer requires writable current directory; it always
  1809 reloads .ML *and* .thy file, if either one is out of date;
  1810 
  1811 
  1812 *** Classical Reasoner ***
  1813 
  1814 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1815 tactics that use classical reasoning to simplify a subgoal without
  1816 splitting it into several subgoals;
  1817 
  1818 * Safe_tac: like safe_tac but uses the default claset;
  1819 
  1820 
  1821 *** Simplifier ***
  1822 
  1823 * added simplification meta rules:
  1824     (asm_)(full_)simplify: simpset -> thm -> thm;
  1825 
  1826 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1827 logics (again);
  1828 
  1829 * added prems argument to simplification procedures;
  1830 
  1831 * HOL, FOL, ZF: added infix function `addsplits':
  1832   instead of `<simpset> setloop (split_tac <thms>)'
  1833   you can simply write `<simpset> addsplits <thms>'
  1834 
  1835 
  1836 *** Syntax ***
  1837 
  1838 * TYPE('a) syntax for type reflection terms;
  1839 
  1840 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1841 
  1842 * pretty printer: changed order of mixfix annotation preference (again!);
  1843 
  1844 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1845 
  1846 
  1847 *** HOL ***
  1848 
  1849 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1850   with `addloop' of the simplifier to faciliate case splitting in premises.
  1851 
  1852 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1853 
  1854 * HOL/Auth: new protocol proofs including some for the Internet
  1855   protocol TLS;
  1856 
  1857 * HOL/Map: new theory of `maps' a la VDM;
  1858 
  1859 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1860 cancelling out common nat summands from =, <, <= (in)equalities, or
  1861 differences; simplification procedures nat_cancel_factor for
  1862 cancelling common factor from =, <, <= (in)equalities over natural
  1863 sums; nat_cancel contains both kinds of procedures, it is installed by
  1864 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1865 
  1866 * HOL/simplifier: terms of the form
  1867   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1868   are rewritten to
  1869   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1870   and those of the form
  1871   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1872   are rewritten to
  1873   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1874 
  1875 * HOL/datatype
  1876   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1877 
  1878   P(t_case f1 ... fn x) =
  1879      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1880         ...
  1881        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1882      )
  1883 
  1884   and a theorem `split_t_case_asm' of the form
  1885 
  1886   P(t_case f1 ... fn x) =
  1887     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1888         ...
  1889        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1890      )
  1891   which can be added to a simpset via `addsplits'. The existing theorems
  1892   expand_list_case and expand_option_case have been renamed to
  1893   split_list_case and split_option_case.
  1894 
  1895 * HOL/Arithmetic:
  1896   - `pred n' is automatically converted to `n-1'.
  1897     Users are strongly encouraged not to use `pred' any longer,
  1898     because it will disappear altogether at some point.
  1899   - Users are strongly encouraged to write "0 < n" rather than
  1900     "n ~= 0". Theorems and proof tools have been modified towards this
  1901     `standard'.
  1902 
  1903 * HOL/Lists:
  1904   the function "set_of_list" has been renamed "set" (and its theorems too);
  1905   the function "nth" now takes its arguments in the reverse order and
  1906   has acquired the infix notation "!" as in "xs!n".
  1907 
  1908 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1909 
  1910 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1911   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1912 
  1913 * HOL/record: extensible records with schematic structural subtyping
  1914 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1915 still lacks various theorems and concrete record syntax;
  1916 
  1917 
  1918 *** HOLCF ***
  1919 
  1920 * removed "axioms" and "generated by" sections;
  1921 
  1922 * replaced "ops" section by extended "consts" section, which is capable of
  1923   handling the continuous function space "->" directly;
  1924 
  1925 * domain package:
  1926   . proves theorems immediately and stores them in the theory,
  1927   . creates hierachical name space,
  1928   . now uses normal mixfix annotations (instead of cinfix...),
  1929   . minor changes to some names and values (for consistency),
  1930   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1931   . separator between mutual domain defs: changed "," to "and",
  1932   . improved handling of sort constraints;  now they have to
  1933     appear on the left-hand side of the equations only;
  1934 
  1935 * fixed LAM <x,y,zs>.b syntax;
  1936 
  1937 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1938 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1939 
  1940 
  1941 *** FOL and ZF ***
  1942 
  1943 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1944   with `addloop' of the simplifier to faciliate case splitting in premises.
  1945 
  1946 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1947 in HOL, they strip ALL and --> from proved theorems;
  1948 
  1949 
  1950 
  1951 New in Isabelle94-8 (May 1997)
  1952 ------------------------------
  1953 
  1954 *** General Changes ***
  1955 
  1956 * new utilities to build / run / maintain Isabelle etc. (in parts
  1957 still somewhat experimental); old Makefiles etc. still functional;
  1958 
  1959 * new 'Isabelle System Manual';
  1960 
  1961 * INSTALL text, together with ./configure and ./build scripts;
  1962 
  1963 * reimplemented type inference for greater efficiency, better error
  1964 messages and clean internal interface;
  1965 
  1966 * prlim command for dealing with lots of subgoals (an easier way of
  1967 setting goals_limit);
  1968 
  1969 
  1970 *** Syntax ***
  1971 
  1972 * supports alternative (named) syntax tables (parser and pretty
  1973 printer); internal interface is provided by add_modesyntax(_i);
  1974 
  1975 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1976 be used in conjunction with the Isabelle symbol font; uses the
  1977 "symbols" syntax table;
  1978 
  1979 * added token_translation interface (may translate name tokens in
  1980 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1981 the current print_mode); IMPORTANT: user print translation functions
  1982 are responsible for marking newly introduced bounds
  1983 (Syntax.mark_boundT);
  1984 
  1985 * token translations for modes "xterm" and "xterm_color" that display
  1986 names in bold, underline etc. or colors (which requires a color
  1987 version of xterm);
  1988 
  1989 * infixes may now be declared with names independent of their syntax;
  1990 
  1991 * added typed_print_translation (like print_translation, but may
  1992 access type of constant);
  1993 
  1994 
  1995 *** Classical Reasoner ***
  1996 
  1997 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1998 some limitations.  Blast_tac...
  1999   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2000   + ignores elimination rules that don't have the correct format
  2001         (the conclusion MUST be a formula variable)
  2002   + ignores types, which can make HOL proofs fail
  2003   + rules must not require higher-order unification, e.g. apply_type in ZF
  2004     [message "Function Var's argument not a bound variable" relates to this]
  2005   + its proof strategy is more general but can actually be slower
  2006 
  2007 * substitution with equality assumptions no longer permutes other
  2008 assumptions;
  2009 
  2010 * minor changes in semantics of addafter (now called addaltern); renamed
  2011 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2012 (and access functions for it);
  2013 
  2014 * improved combination of classical reasoner and simplifier:
  2015   + functions for handling clasimpsets
  2016   + improvement of addss: now the simplifier is called _after_ the
  2017     safe steps.
  2018   + safe variant of addss called addSss: uses safe simplifications
  2019     _during_ the safe steps. It is more complete as it allows multiple
  2020     instantiations of unknowns (e.g. with slow_tac).
  2021 
  2022 *** Simplifier ***
  2023 
  2024 * added interface for simplification procedures (functions that
  2025 produce *proven* rewrite rules on the fly, depending on current
  2026 redex);
  2027 
  2028 * ordering on terms as parameter (used for ordered rewriting);
  2029 
  2030 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2031 
  2032 * the solver is now split into a safe and an unsafe part.
  2033 This should be invisible for the normal user, except that the
  2034 functions setsolver and addsolver have been renamed to setSolver and
  2035 addSolver; added safe_asm_full_simp_tac;
  2036 
  2037 
  2038 *** HOL ***
  2039 
  2040 * a generic induction tactic `induct_tac' which works for all datatypes and
  2041 also for type `nat';
  2042 
  2043 * a generic case distinction tactic `exhaust_tac' which works for all
  2044 datatypes and also for type `nat';
  2045 
  2046 * each datatype comes with a function `size';
  2047 
  2048 * patterns in case expressions allow tuple patterns as arguments to
  2049 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2050 
  2051 * primrec now also works with type nat;
  2052 
  2053 * recdef: a new declaration form, allows general recursive functions to be
  2054 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2055 
  2056 * the constant for negation has been renamed from "not" to "Not" to
  2057 harmonize with FOL, ZF, LK, etc.;
  2058 
  2059 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2060 infinite lists;
  2061 
  2062 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2063 
  2064 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2065 problems in commutative rings, using axiomatic type classes for + and *;
  2066 
  2067 * more examples in HOL/MiniML and HOL/Auth;
  2068 
  2069 * more default rewrite rules for quantifiers, union/intersection;
  2070 
  2071 * a new constant `arbitrary == @x.False';
  2072 
  2073 * HOLCF/IOA replaces old HOL/IOA;
  2074 
  2075 * HOLCF changes: derived all rules and arities
  2076   + axiomatic type classes instead of classes
  2077   + typedef instead of faking type definitions
  2078   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2079   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2080   + eliminated the types void, one, tr
  2081   + use unit lift and bool lift (with translations) instead of one and tr
  2082   + eliminated blift from Lift3.thy (use Def instead of blift)
  2083   all eliminated rules are derived as theorems --> no visible changes ;
  2084 
  2085 
  2086 *** ZF ***
  2087 
  2088 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2089 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2090 as ZF_cs addSIs [equalityI];
  2091 
  2092 
  2093 
  2094 New in Isabelle94-7 (November 96)
  2095 ---------------------------------
  2096 
  2097 * allowing negative levels (as offsets) in prlev and choplev;
  2098 
  2099 * super-linear speedup for large simplifications;
  2100 
  2101 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2102 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2103 FAIL); can suppress it using the command Delsimps (ex_simps @
  2104 all_simps); De Morgan laws are also now included, by default;
  2105 
  2106 * improved printing of ==>  :  ~:
  2107 
  2108 * new object-logic "Sequents" adds linear logic, while replacing LK
  2109 and Modal (thanks to Sara Kalvala);
  2110 
  2111 * HOL/Auth: correctness proofs for authentication protocols;
  2112 
  2113 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2114 examples on HOL/Auth);
  2115 
  2116 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2117 the rewriter and classical reasoner simultaneously;
  2118 
  2119 * function uresult no longer returns theorems in "standard" format;
  2120 regain previous version by: val uresult = standard o uresult;
  2121 
  2122 
  2123 
  2124 New in Isabelle94-6
  2125 -------------------
  2126 
  2127 * oracles -- these establish an interface between Isabelle and trusted
  2128 external reasoners, which may deliver results as theorems;
  2129 
  2130 * proof objects (in particular record all uses of oracles);
  2131 
  2132 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2133 
  2134 * "constdefs" section in theory files;
  2135 
  2136 * "primrec" section (HOL) no longer requires names;
  2137 
  2138 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2139 
  2140 
  2141 
  2142 New in Isabelle94-5
  2143 -------------------
  2144 
  2145 * reduced space requirements;
  2146 
  2147 * automatic HTML generation from theories;
  2148 
  2149 * theory files no longer require "..." (quotes) around most types;
  2150 
  2151 * new examples, including two proofs of the Church-Rosser theorem;
  2152 
  2153 * non-curried (1994) version of HOL is no longer distributed;
  2154 
  2155 
  2156 
  2157 New in Isabelle94-4
  2158 -------------------
  2159 
  2160 * greatly reduced space requirements;
  2161 
  2162 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2163 
  2164 * searchable theorem database (see the section "Retrieving theorems" on
  2165 page 8 of the Reference Manual);
  2166 
  2167 * new examples, including Grabczewski's monumental case study of the
  2168 Axiom of Choice;
  2169 
  2170 * The previous version of HOL renamed to Old_HOL;
  2171 
  2172 * The new version of HOL (previously called CHOL) uses a curried syntax
  2173 for functions.  Application looks like f a b instead of f(a,b);
  2174 
  2175 * Mutually recursive inductive definitions finally work in HOL;
  2176 
  2177 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2178 translates to the operator "split";
  2179 
  2180 
  2181 
  2182 New in Isabelle94-3
  2183 -------------------
  2184 
  2185 * new infix operator, addss, allowing the classical reasoner to
  2186 perform simplification at each step of its search.  Example:
  2187         fast_tac (cs addss ss)
  2188 
  2189 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2190 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2191 look like (a,b) instead of <a,b>;
  2192 
  2193 * PLEASE NOTE: CHOL will eventually replace HOL!
  2194 
  2195 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2196 It translates to the operator "split".  A new theory of integers is available;
  2197 
  2198 * In ZF, integer numerals now denote two's-complement binary integers.
  2199 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2200 
  2201 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2202 of the Axiom of Choice;
  2203 
  2204 
  2205 
  2206 New in Isabelle94-2
  2207 -------------------
  2208 
  2209 * Significantly faster resolution;
  2210 
  2211 * the different sections in a .thy file can now be mixed and repeated
  2212 freely;
  2213 
  2214 * Database of theorems for FOL, HOL and ZF.  New
  2215 commands including qed, qed_goal and bind_thm store theorems in the database.
  2216 
  2217 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2218 a given theory (thms_of), or find out what theory a theorem was proved in
  2219 (theory_of_thm);
  2220 
  2221 * Bugs fixed in the inductive definition and datatype packages;
  2222 
  2223 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2224 and HOL_dup_cs obsolete;
  2225 
  2226 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2227 have been removed;
  2228 
  2229 * Simpler definition of function space in ZF;
  2230 
  2231 * new results about cardinal and ordinal arithmetic in ZF;
  2232 
  2233 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2234 types;
  2235 
  2236 
  2237 $Id$