NEWS
author nipkow
Tue Aug 13 21:59:44 2002 +0200 (2002-08-13)
changeset 13500 2222c7a0e8bb
parent 13492 6aae8eb39a18
child 13518 a0749ce05100
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 * Pure: locale specifications now produce predicate definitions
    10 according to the body of text (covering assumptions modulo local
    11 definitions); predicate "loc_axioms" covers newly introduced text,
    12 while "loc" is cumulative wrt. all included locale expressions; the
    13 latter view is presented only on export into the global theory
    14 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    15 on the old view without predicates;
    16 
    17 * Pure: predefined locales "var" and "struct" are useful for sharing
    18 parameters (as in CASL, for example); just specify something like
    19 ``var x + var y + struct M'' as import;
    20 
    21 * Pure: improved thms_containing: proper indexing of facts instead of
    22 raw theorems; check validity of results wrt. current name space;
    23 include local facts of proof configuration (also covers active
    24 locales); an optional limit for the number of printed facts may be
    25 given (the default is 40);
    26 
    27 * Provers: improved induct method: assumptions introduced by case
    28 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    29 the goal statement); "foo" still refers to all facts collectively;
    30 
    31 
    32 *** HOL ***
    33 
    34 * 'typedef' command has new option "open" to suppress the set
    35 definition;
    36 
    37 * Functions Min and Max on finite sets have been introduced.
    38   (theory Finite_Set)
    39 
    40 * attribute [symmetric] now works for relations as well; it turns
    41 (x,y) : R^-1 into (y,x) : R, and vice versa;
    42 
    43 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    44   In ProofGeneral the counter example appears in the trace buffer.
    45 
    46 * arith(_tac) does now know about div k and mod k where k is a numeral
    47 of type nat or int. It can solve simple goals like
    48 
    49   "0 < n ==> n div 2 < (n::nat)"
    50 
    51 but fails if divisibility plays a role like in
    52 
    53   "n div 2 + (n+1) div 2 = (n::nat)"
    54 
    55 * simp's arithmetic capabilities have been enhanced a bit: it now
    56 takes ~= in premises into account (by performing a case split);
    57 
    58 
    59 *** ML ***
    60 
    61 * Pure: Tactic.prove provides sane interface for internal proofs;
    62 omits the infamous "standard" operation, so this is more appropriate
    63 than prove_goalw_cterm in many situations (e.g. in simprocs);
    64 
    65 * Pure: improved error reporting of simprocs;
    66 
    67 * Provers: Simplifier.simproc(_i) provides sane interface for setting
    68 up simprocs;
    69 
    70 
    71 
    72 New in Isabelle2002 (March 2002)
    73 --------------------------------
    74 
    75 *** Document preparation ***
    76 
    77 * greatly simplified document preparation setup, including more
    78 graceful interpretation of isatool usedir -i/-d/-D options, and more
    79 instructive isatool mkdir; users should basically be able to get
    80 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    81 users may run a separate document processing stage manually like this:
    82 "isatool usedir -D output HOL Test && isatool document Test/output";
    83 
    84 * theory dependency graph may now be incorporated into documents;
    85 isatool usedir -g true will produce session_graph.eps/.pdf for use
    86 with \includegraphics of LaTeX;
    87 
    88 * proper spacing of consecutive markup elements, especially text
    89 blocks after section headings;
    90 
    91 * support bold style (for single symbols only), input syntax is like
    92 this: "\<^bold>\<alpha>" or "\<^bold>A";
    93 
    94 * \<bullet> is now output as bold \cdot by default, which looks much
    95 better in printed text;
    96 
    97 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    98 note that these symbols are currently unavailable in Proof General /
    99 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   100 
   101 * isatool latex no longer depends on changed TEXINPUTS, instead
   102 isatool document copies the Isabelle style files to the target
   103 location;
   104 
   105 
   106 *** Isar ***
   107 
   108 * Pure/Provers: improved proof by cases and induction;
   109   - 'case' command admits impromptu naming of parameters (such as
   110     "case (Suc n)");
   111   - 'induct' method divinates rule instantiation from the inductive
   112     claim; no longer requires excessive ?P bindings for proper
   113     instantiation of cases;
   114   - 'induct' method properly enumerates all possibilities of set/type
   115     rules; as a consequence facts may be also passed through *type*
   116     rules without further ado;
   117   - 'induct' method now derives symbolic cases from the *rulified*
   118     rule (before it used to rulify cases stemming from the internal
   119     atomized version); this means that the context of a non-atomic
   120     statement becomes is included in the hypothesis, avoiding the
   121     slightly cumbersome show "PROP ?case" form;
   122   - 'induct' may now use elim-style induction rules without chaining
   123     facts, using ``missing'' premises from the goal state; this allows
   124     rules stemming from inductive sets to be applied in unstructured
   125     scripts, while still benefitting from proper handling of non-atomic
   126     statements; NB: major inductive premises need to be put first, all
   127     the rest of the goal is passed through the induction;
   128   - 'induct' proper support for mutual induction involving non-atomic
   129     rule statements (uses the new concept of simultaneous goals, see
   130     below);
   131   - append all possible rule selections, but only use the first
   132     success (no backtracking);
   133   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   134   - undeclared rule case names default to numbers 1, 2, 3, ...;
   135   - added 'print_induct_rules' (covered by help item in recent Proof
   136     General versions);
   137   - moved induct/cases attributes to Pure, methods to Provers;
   138   - generic method setup instantiated for FOL and HOL;
   139 
   140 * Pure: support multiple simultaneous goal statements, for example
   141 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   142 meta-level mechanism, this acts as if several individual goals had
   143 been stated separately; in particular common proof methods need to be
   144 repeated in order to cover all claims; note that a single elimination
   145 step is *not* sufficient to establish the two conjunctions, so this
   146 fails:
   147 
   148   assume "A & B" then have A and B ..   (*".." fails*)
   149 
   150 better use "obtain" in situations as above; alternative refer to
   151 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   152 
   153 * Pure: proper integration with ``locales''; unlike the original
   154 version by Florian Kammüller, Isar locales package high-level proof
   155 contexts rather than raw logical ones (e.g. we admit to include
   156 attributes everywhere); operations on locales include merge and
   157 rename; support for implicit arguments (``structures''); simultaneous
   158 type-inference over imports and text; see also HOL/ex/Locales.thy for
   159 some examples;
   160 
   161 * Pure: the following commands have been ``localized'', supporting a
   162 target locale specification "(in name)": 'lemma', 'theorem',
   163 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   164 stored both within the locale and at the theory level (exported and
   165 qualified by the locale name);
   166 
   167 * Pure: theory goals may now be specified in ``long'' form, with
   168 ad-hoc contexts consisting of arbitrary locale elements. for example
   169 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   170 definitions may be given, too); the result is a meta-level rule with
   171 the context elements being discharged in the obvious way;
   172 
   173 * Pure: new proof command 'using' allows to augment currently used
   174 facts after a goal statement ('using' is syntactically analogous to
   175 'apply', but acts on the goal's facts only); this allows chained facts
   176 to be separated into parts given before and after a claim, as in
   177 ``from a and b have C using d and e <proof>'';
   178 
   179 * Pure: renamed "antecedent" case to "rule_context";
   180 
   181 * Pure: new 'judgment' command records explicit information about the
   182 object-logic embedding (used by several tools internally); no longer
   183 use hard-wired "Trueprop";
   184 
   185 * Pure: added 'corollary' command;
   186 
   187 * Pure: fixed 'token_translation' command;
   188 
   189 * Pure: removed obsolete 'exported' attribute;
   190 
   191 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   192 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   193 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   194 
   195 * Pure: method 'atomize' presents local goal premises as object-level
   196 statements (atomic meta-level propositions); setup controlled via
   197 rewrite rules declarations of 'atomize' attribute; example
   198 application: 'induct' method with proper rule statements in improper
   199 proof *scripts*;
   200 
   201 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   202 now consider the syntactic context of assumptions, giving a better
   203 chance to get type-inference of the arguments right (this is
   204 especially important for locales);
   205 
   206 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   207 mode;
   208 
   209 * Pure/obtain: the formal conclusion "thesis", being marked as
   210 ``internal'', may no longer be reference directly in the text;
   211 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   212 situations;
   213 
   214 * Pure: generic 'sym' attribute which declares a rule both as pure
   215 'elim?' and for the 'symmetric' operation;
   216 
   217 * Pure: marginal comments ``--'' may now occur just anywhere in the
   218 text; the fixed correlation with particular command syntax has been
   219 discontinued;
   220 
   221 * Pure: new method 'rules' is particularly well-suited for proof
   222 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   223 but often produces more compact proof terms with less detours;
   224 
   225 * Pure/Provers/classical: simplified integration with pure rule
   226 attributes and methods; the classical "intro?/elim?/dest?"
   227 declarations coincide with the pure ones; the "rule" method no longer
   228 includes classically swapped intros; "intro" and "elim" methods no
   229 longer pick rules from the context; also got rid of ML declarations
   230 AddXIs/AddXEs/AddXDs; all of this has some potential for
   231 INCOMPATIBILITY;
   232 
   233 * Provers/classical: attribute 'swapped' produces classical inversions
   234 of introduction rules;
   235 
   236 * Provers/simplifier: 'simplified' attribute may refer to explicit
   237 rules instead of full simplifier context; 'iff' attribute handles
   238 conditional rules;
   239 
   240 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   241 
   242 * HOL: 'recdef' now fails on unfinished automated proofs, use
   243 "(permissive)" option to recover old behavior;
   244 
   245 * HOL: 'inductive' no longer features separate (collective) attributes
   246 for 'intros' (was found too confusing);
   247 
   248 * HOL: properly declared induction rules less_induct and
   249 wf_induct_rule;
   250 
   251 
   252 *** HOL ***
   253 
   254 * HOL: moved over to sane numeral syntax; the new policy is as
   255 follows:
   256 
   257   - 0 and 1 are polymorphic constants, which are defined on any
   258   numeric type (nat, int, real etc.);
   259 
   260   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   261   binary representation internally;
   262 
   263   - type nat has special constructor Suc, and generally prefers Suc 0
   264   over 1::nat and Suc (Suc 0) over 2::nat;
   265 
   266 This change may cause significant problems of INCOMPATIBILITY; here
   267 are some hints on converting existing sources:
   268 
   269   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   270   entities, so expressions involving "-" (unary or binary minus) need
   271   to be spaced properly;
   272 
   273   - existing occurrences of "1" may need to be constraint "1::nat" or
   274   even replaced by Suc 0; similar for old "2";
   275 
   276   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   277 
   278   - remove all special provisions on numerals in proofs;
   279 
   280 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   281 representation (depends on bin_arith_simps in the default context);
   282 
   283 * HOL: symbolic syntax for x^2 (numeral 2);
   284 
   285 * HOL: the class of all HOL types is now called "type" rather than
   286 "term"; INCOMPATIBILITY, need to adapt references to this type class
   287 in axclass/classes, instance/arities, and (usually rare) occurrences
   288 in typings (of consts etc.); internally the class is called
   289 "HOL.type", ML programs should refer to HOLogic.typeS;
   290 
   291 * HOL/record package improvements:
   292   - new derived operations "fields" to build a partial record section,
   293     "extend" to promote a fixed record to a record scheme, and
   294     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   295     declared as simp by default;
   296   - shared operations ("more", "fields", etc.) now need to be always
   297     qualified) --- potential INCOMPATIBILITY;
   298   - removed "make_scheme" operations (use "make" with "extend") --
   299     INCOMPATIBILITY;
   300   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   301   - provides cases/induct rules for use with corresponding Isar
   302     methods (for concrete records, record schemes, concrete more
   303     parts, and schematic more parts -- in that order);
   304   - internal definitions directly based on a light-weight abstract
   305     theory of product types over typedef rather than datatype;
   306 
   307 * HOL: generic code generator for generating executable ML code from
   308 specifications; specific support for HOL constructs such as inductive
   309 datatypes and sets, as well as recursive functions; can be invoked
   310 via 'generate_code' theory section;
   311 
   312 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   313 
   314 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   315 (beware of argument permutation!);
   316 
   317 * HOL: linorder_less_split superseded by linorder_cases;
   318 
   319 * HOL/List: "nodups" renamed to "distinct";
   320 
   321 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   322 to peripheral theory "Hilbert_Choice";
   323 
   324 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   325 in this (rare) case use:
   326 
   327   delSWrapper "split_all_tac"
   328   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   329 
   330 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   331 MAY FAIL;
   332 
   333 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   334 Isabelle's type classes, ^ on functions and relations has too general
   335 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   336 necessary to attach explicit type constraints;
   337 
   338 * HOL/Relation: the prefix name of the infix "O" has been changed from
   339 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   340 renamed accordingly (eg "compI" -> "rel_compI").
   341 
   342 * HOL: syntax translations now work properly with numerals and records
   343 expressions;
   344 
   345 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   346 of "lam" -- INCOMPATIBILITY;
   347 
   348 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   349 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   350 renamed "Product_Type.unit";
   351 
   352 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   353 
   354 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   355 the "cases" method);
   356 
   357 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   358 Florian Kammüller);
   359 
   360 * HOL/IMP: updated and converted to new-style theory format; several
   361 parts turned into readable document, with proper Isar proof texts and
   362 some explanations (by Gerwin Klein);
   363 
   364 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   365 
   366 * HOL-Hyperreal is now a logic image;
   367 
   368 
   369 *** HOLCF ***
   370 
   371 * Isar: consts/constdefs supports mixfix syntax for continuous
   372 operations;
   373 
   374 * Isar: domain package adapted to new-style theory format, e.g. see
   375 HOLCF/ex/Dnat.thy;
   376 
   377 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   378 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   379 lift.induct_tac, always use UU instead of Undef;
   380 
   381 * HOLCF/IMP: updated and converted to new-style theory;
   382 
   383 
   384 *** ZF ***
   385 
   386 * Isar: proper integration of logic-specific tools and packages,
   387 including theory commands '(co)inductive', '(co)datatype',
   388 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   389 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   390 
   391 * theory Main no longer includes AC; for the Axiom of Choice, base
   392 your theory on Main_ZFC;
   393 
   394 * the integer library now covers quotients and remainders, with many
   395 laws relating division to addition, multiplication, etc.;
   396 
   397 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   398 typeless version of the formalism;
   399 
   400 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   401 format;
   402 
   403 * ZF/Induct: new directory for examples of inductive definitions,
   404 including theory Multiset for multiset orderings; converted to
   405 new-style theory format;
   406 
   407 * ZF: many new theorems about lists, ordinals, etc.;
   408 
   409 
   410 *** General ***
   411 
   412 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   413 variable proof controls level of detail: 0 = no proofs (only oracle
   414 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   415 also ref manual for further ML interfaces;
   416 
   417 * Pure/axclass: removed obsolete ML interface
   418 goal_subclass/goal_arity;
   419 
   420 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   421 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   422 separate tokens, so expressions involving minus need to be spaced
   423 properly;
   424 
   425 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   426 rather than "infixl" or "infixr";
   427 
   428 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   429 sort constraint specifications in type inference; e.g. "x::_::foo"
   430 ensures that the type of "x" is of sort "foo" (but not necessarily a
   431 type variable);
   432 
   433 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   434 control output of nested => (types); the default behavior is
   435 "type_brackets";
   436 
   437 * Pure/syntax: builtin parse translation for "_constify" turns valued
   438 tokens into AST constants;
   439 
   440 * Pure/syntax: prefer later declarations of translations and print
   441 translation functions; potential INCOMPATIBILITY: need to reverse
   442 multiple declarations for same syntax element constant;
   443 
   444 * Pure/show_hyps reset by default (in accordance to existing Isar
   445 practice);
   446 
   447 * Provers/classical: renamed addaltern to addafter, addSaltern to
   448 addSafter;
   449 
   450 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   451 as well;
   452 
   453 * system: tested support for MacOS X; should be able to get Isabelle +
   454 Proof General to work in a plain Terminal after installing Poly/ML
   455 (e.g. from the Isabelle distribution area) and GNU bash alone
   456 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   457 support requires further installations, e.g. from
   458 http://fink.sourceforge.net/);
   459 
   460 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   461 
   462 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   463 of 40 MB), cf. ML_OPTIONS;
   464 
   465 * system: Proof General keywords specification is now part of the
   466 Isabelle distribution (see etc/isar-keywords.el);
   467 
   468 * system: support for persistent Proof General sessions (refrain from
   469 outdating all loaded theories on startup); user may create writable
   470 logic images like this: ``isabelle -q HOL Test'';
   471 
   472 * system: smart selection of Isabelle process versus Isabelle
   473 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   474 run both "isabelle" and "Isabelle" even if file names are badly
   475 damaged (executable inspects the case of the first letter of its own
   476 name); added separate "isabelle-process" and "isabelle-interface";
   477 
   478 * system: refrain from any attempt at filtering input streams; no
   479 longer support ``8bit'' encoding of old isabelle font, instead proper
   480 iso-latin characters may now be used; the related isatools
   481 "symbolinput" and "nonascii" have disappeared as well;
   482 
   483 * system: removed old "xterm" interface (the print modes "xterm" and
   484 "xterm_color" are still available for direct use in a suitable
   485 terminal);
   486 
   487 
   488 
   489 New in Isabelle99-2 (February 2001)
   490 -----------------------------------
   491 
   492 *** Overview of INCOMPATIBILITIES ***
   493 
   494 * HOL: please note that theories in the Library and elsewhere often use the
   495 new-style (Isar) format; to refer to their theorems in an ML script you must
   496 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   497 
   498 * HOL: inductive package no longer splits induction rule aggressively,
   499 but only as far as specified by the introductions given; the old
   500 format may be recovered via ML function complete_split_rule or attribute
   501 'split_rule (complete)';
   502 
   503 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   504 gfp_Tarski to gfp_unfold;
   505 
   506 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   507 
   508 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   509 relation); infix "^^" has been renamed "``"; infix "``" has been
   510 renamed "`"; "univalent" has been renamed "single_valued";
   511 
   512 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   513 operation;
   514 
   515 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   516 
   517 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   518 
   519 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   520 consequence, it is no longer monotonic wrt. the local goal context
   521 (which is now passed through the inductive cases);
   522 
   523 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   524 \<gg> to \<ggreater>;
   525 
   526 
   527 *** Document preparation ***
   528 
   529 * \isabellestyle{NAME} selects version of Isabelle output (currently
   530 available: are "it" for near math-mode best-style output, "sl" for
   531 slanted text style, and "tt" for plain type-writer; if no
   532 \isabellestyle command is given, output is according to slanted
   533 type-writer);
   534 
   535 * support sub/super scripts (for single symbols only), input syntax is
   536 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   537 
   538 * some more standard symbols; see Appendix A of the system manual for
   539 the complete list of symbols defined in isabellesym.sty;
   540 
   541 * improved isabelle style files; more abstract symbol implementation
   542 (should now use \isamath{...} and \isatext{...} in custom symbol
   543 definitions);
   544 
   545 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   546 state; Note that presentation of goal states does not conform to
   547 actual human-readable proof documents.  Please do not include goal
   548 states into document output unless you really know what you are doing!
   549 
   550 * proper indentation of antiquoted output with proportional LaTeX
   551 fonts;
   552 
   553 * no_document ML operator temporarily disables LaTeX document
   554 generation;
   555 
   556 * isatool unsymbolize tunes sources for plain ASCII communication;
   557 
   558 
   559 *** Isar ***
   560 
   561 * Pure: Isar now suffers initial goal statements to contain unbound
   562 schematic variables (this does not conform to actual readable proof
   563 documents, due to unpredictable outcome and non-compositional proof
   564 checking); users who know what they are doing may use schematic goals
   565 for Prolog-style synthesis of proven results;
   566 
   567 * Pure: assumption method (an implicit finishing) now handles actual
   568 rules as well;
   569 
   570 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   571 initial goal, declare "that" only as Pure intro (only for single
   572 steps); the "that" rule assumption may now be involved in implicit
   573 finishing, thus ".." becomes a feasible for trivial obtains;
   574 
   575 * Pure: default proof step now includes 'intro_classes'; thus trivial
   576 instance proofs may be performed by "..";
   577 
   578 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   579 statements as well;
   580 
   581 * Pure: more robust selection of calculational rules;
   582 
   583 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   584 rule (as well as the assumption rule);
   585 
   586 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   587 lemmas, using the graph browser tool;
   588 
   589 * Pure: predict failure of "show" in interactive mode;
   590 
   591 * Pure: 'thms_containing' now takes actual terms as arguments;
   592 
   593 * HOL: improved method 'induct' --- now handles non-atomic goals
   594 (potential INCOMPATIBILITY); tuned error handling;
   595 
   596 * HOL: cases and induct rules now provide explicit hints about the
   597 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   598 any remaining facts are inserted into the goal verbatim;
   599 
   600 * HOL: local contexts (aka cases) may now contain term bindings as
   601 well; the 'cases' and 'induct' methods new provide a ?case binding for
   602 the result to be shown in each case;
   603 
   604 * HOL: added 'recdef_tc' command;
   605 
   606 * isatool convert assists in eliminating legacy ML scripts;
   607 
   608 
   609 *** HOL ***
   610 
   611 * HOL/Library: a collection of generic theories to be used together
   612 with main HOL; the theory loader path already includes this directory
   613 by default; the following existing theories have been moved here:
   614 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   615 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   616 
   617 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   618 modelling and verification task performed in Isabelle/HOL +
   619 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   620 
   621 * HOL/Algebra: special summation operator SUM no longer exists, it has
   622 been replaced by setsum; infix 'assoc' now has priority 50 (like
   623 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   624 'domain', this makes the theory consistent with mathematical
   625 literature;
   626 
   627 * HOL basics: added overloaded operations "inverse" and "divide"
   628 (infix "/"), syntax for generic "abs" operation, generic summation
   629 operator \<Sum>;
   630 
   631 * HOL/typedef: simplified package, provide more useful rules (see also
   632 HOL/subset.thy);
   633 
   634 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   635 now expressed as a proper nested rule (old-style tactic scripts may
   636 require atomize_strip_tac to cope with non-atomic premises);
   637 
   638 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   639 to "split_conv" (old name still available for compatibility);
   640 
   641 * HOL: improved concrete syntax for strings (e.g. allows translation
   642 rules with string literals);
   643 
   644 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   645  and Fleuriot's mechanization of analysis, including the transcendental
   646  functions for the reals;
   647 
   648 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   649 
   650 
   651 *** CTT ***
   652 
   653 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   654 "lam" is displayed as TWO lambda-symbols
   655 
   656 * CTT: theory Main now available, containing everything (that is, Bool
   657 and Arith);
   658 
   659 
   660 *** General ***
   661 
   662 * Pure: the Simplifier has been implemented properly as a derived rule
   663 outside of the actual kernel (at last!); the overall performance
   664 penalty in practical applications is about 50%, while reliability of
   665 the Isabelle inference kernel has been greatly improved;
   666 
   667 * print modes "brackets" and "no_brackets" control output of nested =>
   668 (types) and ==> (props); the default behaviour is "brackets";
   669 
   670 * Provers: fast_tac (and friends) now handle actual object-logic rules
   671 as assumptions as well;
   672 
   673 * system: support Poly/ML 4.0;
   674 
   675 * system: isatool install handles KDE version 1 or 2;
   676 
   677 
   678 
   679 New in Isabelle99-1 (October 2000)
   680 ----------------------------------
   681 
   682 *** Overview of INCOMPATIBILITIES ***
   683 
   684 * HOL: simplification of natural numbers is much changed; to partly
   685 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   686 issue the following ML commands:
   687 
   688   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   689   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   690 
   691 * HOL: simplification no longer dives into case-expressions; this is
   692 controlled by "t.weak_case_cong" for each datatype t;
   693 
   694 * HOL: nat_less_induct renamed to less_induct;
   695 
   696 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   697 fixsome to patch .thy and .ML sources automatically;
   698 
   699   select_equality  -> some_equality
   700   select_eq_Ex     -> some_eq_ex
   701   selectI2EX       -> someI2_ex
   702   selectI2         -> someI2
   703   selectI          -> someI
   704   select1_equality -> some1_equality
   705   Eps_sym_eq       -> some_sym_eq_trivial
   706   Eps_eq           -> some_eq_trivial
   707 
   708 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   709 
   710 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   711 instead);
   712 
   713 * HOL: the recursion equations generated by 'recdef' are now called
   714 f.simps instead of f.rules;
   715 
   716 * HOL: qed_spec_mp now also handles bounded ALL as well;
   717 
   718 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   719 sometimes be needed;
   720 
   721 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   722 
   723 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   724 
   725 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   726 product is now "<*>" instead of "Times"; the lexicographic product is
   727 now "<*lex*>" instead of "**";
   728 
   729 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   730 of main HOL, but was unused); better use HOL's datatype package;
   731 
   732 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   733 the old syntax may be recovered as follows:
   734 
   735   syntax (symbols)
   736     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   737       (infixl "\\<oplus>" 100)
   738 
   739 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   740 
   741 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   742 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   743 internally;
   744 
   745 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   746 changed from A/r to A//r;
   747 
   748 * ZF: new treatment of arithmetic (nat & int) may break some old
   749 proofs;
   750 
   751 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   752 rulify -> rule_format, elimify -> elim_format, ...);
   753 
   754 * Isar/Provers: intro/elim/dest attributes changed; renamed
   755 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   756 should have to change intro!! to intro? only); replaced "delrule" by
   757 "rule del";
   758 
   759 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   760 
   761 * Provers: strengthened force_tac by using new first_best_tac;
   762 
   763 * LaTeX document preparation: several changes of isabelle.sty (see
   764 lib/texinputs);
   765 
   766 
   767 *** Document preparation ***
   768 
   769 * formal comments (text blocks etc.) in new-style theories may now
   770 contain antiquotations of thm/prop/term/typ/text to be presented
   771 according to latex print mode; concrete syntax is like this:
   772 @{term[show_types] "f(x) = a + x"};
   773 
   774 * isatool mkdir provides easy setup of Isabelle session directories,
   775 including proper document sources;
   776 
   777 * generated LaTeX sources are now deleted after successful run
   778 (isatool document -c); may retain a copy somewhere else via -D option
   779 of isatool usedir;
   780 
   781 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   782 style files, achieving self-contained LaTeX sources and simplifying
   783 LaTeX debugging;
   784 
   785 * old-style theories now produce (crude) LaTeX output as well;
   786 
   787 * browser info session directories are now self-contained (may be put
   788 on WWW server seperately); improved graphs of nested sessions; removed
   789 graph for 'all sessions';
   790 
   791 * several improvements in isabelle style files; \isabellestyle{it}
   792 produces fake math mode output; \isamarkupheader is now \section by
   793 default; see lib/texinputs/isabelle.sty etc.;
   794 
   795 
   796 *** Isar ***
   797 
   798 * Isar/Pure: local results and corresponding term bindings are now
   799 subject to Hindley-Milner polymorphism (similar to ML); this
   800 accommodates incremental type-inference very nicely;
   801 
   802 * Isar/Pure: new derived language element 'obtain' supports
   803 generalized existence reasoning;
   804 
   805 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   806 support accumulation of results, without applying any rules yet;
   807 useful to collect intermediate results without explicit name
   808 references, and for use with transitivity rules with more than 2
   809 premises;
   810 
   811 * Isar/Pure: scalable support for case-analysis type proofs: new
   812 'case' language element refers to local contexts symbolically, as
   813 produced by certain proof methods; internally, case names are attached
   814 to theorems as "tags";
   815 
   816 * Isar/Pure: theory command 'hide' removes declarations from
   817 class/type/const name spaces;
   818 
   819 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   820 indicate potential overloading;
   821 
   822 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   823 
   824 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   825 "{a,b,c}" instead of {a,b,c};
   826 
   827 * Isar/Pure now provides its own version of intro/elim/dest
   828 attributes; useful for building new logics, but beware of confusion
   829 with the version in Provers/classical;
   830 
   831 * Isar/Pure: the local context of (non-atomic) goals is provided via
   832 case name 'antecedent';
   833 
   834 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   835 to the current context is now done automatically);
   836 
   837 * Isar/Pure: theory command 'method_setup' provides a simple interface
   838 for definining proof methods in ML;
   839 
   840 * Isar/Provers: intro/elim/dest attributes changed; renamed
   841 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   842 most cases, one should have to change intro!! to intro? only);
   843 replaced "delrule" by "rule del";
   844 
   845 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   846 'symmetric' attribute (the latter supercedes [RS sym]);
   847 
   848 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   849 method modifier); 'simp' method: 'only:' modifier removes loopers as
   850 well (including splits);
   851 
   852 * Isar/Provers: Simplifier and Classical methods now support all kind
   853 of modifiers used in the past, including 'cong', 'iff', etc.
   854 
   855 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   856 of Simplifier and Classical reasoner);
   857 
   858 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   859 now support named cases; major packages (inductive, datatype, primrec,
   860 recdef) support case names and properly name parameters;
   861 
   862 * Isar/HOL: new transitivity rules for substitution in inequalities --
   863 monotonicity conditions are extracted to be proven at end of
   864 calculations;
   865 
   866 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   867 method anyway;
   868 
   869 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   870 split_if split_if_asm; datatype package provides theorems foo.splits =
   871 foo.split foo.split_asm for each datatype;
   872 
   873 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   874 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   875 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   876 use "(cases (simplified))" method in proper proof texts);
   877 
   878 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   879 
   880 * Isar: names of theorems etc. may be natural numbers as well;
   881 
   882 * Isar: 'pr' command: optional arguments for goals_limit and
   883 ProofContext.prems_limit; no longer prints theory contexts, but only
   884 proof states;
   885 
   886 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   887 additional print modes to be specified; e.g. "pr(latex)" will print
   888 proof state according to the Isabelle LaTeX style;
   889 
   890 * Isar: improved support for emulating tactic scripts, including proof
   891 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   892 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   893 (for HOL datatypes);
   894 
   895 * Isar: simplified (more robust) goal selection of proof methods: 1st
   896 goal, all goals, or explicit goal specifier (tactic emulation); thus
   897 'proof method scripts' have to be in depth-first order;
   898 
   899 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   900 
   901 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   902 should instead use individual commands for printing items
   903 (print_commands, print_methods etc.);
   904 
   905 * Isar: added 'nothing' --- the empty list of theorems;
   906 
   907 
   908 *** HOL ***
   909 
   910 * HOL/MicroJava: formalization of a fragment of Java, together with a
   911 corresponding virtual machine and a specification of its bytecode
   912 verifier and a lightweight bytecode verifier, including proofs of
   913 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   914 Cornelia Pusch (see also the homepage of project Bali at
   915 http://isabelle.in.tum.de/Bali/);
   916 
   917 * HOL/Algebra: new theory of rings and univariate polynomials, by
   918 Clemens Ballarin;
   919 
   920 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   921 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   922 Rasmussen;
   923 
   924 * HOL/Lattice: fundamental concepts of lattice theory and order
   925 structures, including duals, properties of bounds versus algebraic
   926 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   927 Theorem for complete lattices etc.; may also serve as a demonstration
   928 for abstract algebraic reasoning using axiomatic type classes, and
   929 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   930 
   931 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   932 von Oheimb;
   933 
   934 * HOL/IMPP: extension of IMP with local variables and mutually
   935 recursive procedures, by David von Oheimb;
   936 
   937 * HOL/Lambda: converted into new-style theory and document;
   938 
   939 * HOL/ex/Multiquote: example of multiple nested quotations and
   940 anti-quotations -- basically a generalized version of de-Bruijn
   941 representation; very useful in avoiding lifting of operations;
   942 
   943 * HOL/record: added general record equality rule to simpset; fixed
   944 select-update simplification procedure to handle extended records as
   945 well; admit "r" as field name;
   946 
   947 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   948 other numeric types and also as the identity of groups, rings, etc.;
   949 
   950 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   951 Types nat and int belong to this axclass;
   952 
   953 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   954    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   955    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   956   two terms #m*u and #n*u are replaced by #(m+n)*u
   957     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   958   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   959     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   960 
   961 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   962 powerful prover for predicate logic but knows nothing of clasets; see
   963 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   964 
   965 * HOL: new version of "case_tac" subsumes both boolean case split and
   966 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   967 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   968 
   969 * HOL: simplification no longer dives into case-expressions: only the
   970 selector expression is simplified, but not the remaining arms; to
   971 enable full simplification of case-expressions for datatype t, you may
   972 remove t.weak_case_cong from the simpset, either globally (Delcongs
   973 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   974 
   975 * HOL/recdef: the recursion equations generated by 'recdef' for
   976 function 'f' are now called f.simps instead of f.rules; if all
   977 termination conditions are proved automatically, these simplification
   978 rules are added to the simpset, as in primrec; rules may be named
   979 individually as well, resulting in a separate list of theorems for
   980 each equation;
   981 
   982 * HOL/While is a new theory that provides a while-combinator. It
   983 permits the definition of tail-recursive functions without the
   984 provision of a termination measure. The latter is necessary once the
   985 invariant proof rule for while is applied.
   986 
   987 * HOL: new (overloaded) notation for the set of elements below/above
   988 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   989 
   990 * HOL: theorems impI, allI, ballI bound as "strip";
   991 
   992 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   993 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   994 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   995 
   996 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   997 
   998 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   999 main HOL, but was unused);
  1000 
  1001 * HOL: fewer consts declared as global (e.g. have to refer to
  1002 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1003 
  1004 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1005 in case of overlap with user translations (e.g. judgements over
  1006 tuples); (note that the underlying logical represenation is still
  1007 bogus);
  1008 
  1009 
  1010 *** ZF ***
  1011 
  1012 * ZF: simplification automatically cancels common terms in arithmetic
  1013 expressions over nat and int;
  1014 
  1015 * ZF: new treatment of nat to minimize type-checking: all operators
  1016 coerce their operands to a natural number using the function natify,
  1017 making the algebraic laws unconditional;
  1018 
  1019 * ZF: as above, for int: operators coerce their operands to an integer
  1020 using the function intify;
  1021 
  1022 * ZF: the integer library now contains many of the usual laws for the
  1023 orderings, including $<=, and monotonicity laws for $+ and $*;
  1024 
  1025 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1026 simplification;
  1027 
  1028 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1029 to the simplifier and classical reasoner simultaneously;
  1030 
  1031 
  1032 *** General ***
  1033 
  1034 * Provers: blast_tac now handles actual object-logic rules as
  1035 assumptions; note that auto_tac uses blast_tac internally as well;
  1036 
  1037 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1038 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1039 
  1040 * Provers: delrules now handles destruct rules as well (no longer need
  1041 explicit make_elim);
  1042 
  1043 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1044   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1045 use instead the strong form,
  1046   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1047 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1048 from destruct-rules;
  1049 
  1050 * Provers: Simplifier.easy_setup provides a fast path to basic
  1051 Simplifier setup for new object-logics;
  1052 
  1053 * Pure: AST translation rules no longer require constant head on LHS;
  1054 
  1055 * Pure: improved name spaces: ambiguous output is qualified; support
  1056 for hiding of names;
  1057 
  1058 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1059 XSYMBOL_HOME; no longer need to do manual configuration in most
  1060 situations;
  1061 
  1062 * system: compression of ML heaps images may now be controlled via -c
  1063 option of isabelle and isatool usedir (currently only observed by
  1064 Poly/ML);
  1065 
  1066 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1067 useful for remote X11);
  1068 
  1069 * system: provide TAGS file for Isabelle sources;
  1070 
  1071 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1072 order;
  1073 
  1074 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1075 timing flag supersedes proof_timing and Toplevel.trace;
  1076 
  1077 * ML: new combinators |>> and |>>> for incremental transformations
  1078 with secondary results (e.g. certain theory extensions):
  1079 
  1080 * ML: PureThy.add_defs gets additional argument to indicate potential
  1081 overloading (usually false);
  1082 
  1083 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1084 results;
  1085 
  1086 
  1087 
  1088 New in Isabelle99 (October 1999)
  1089 --------------------------------
  1090 
  1091 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1092 
  1093 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1094 are no longer simplified.  (This allows the simplifier to unfold recursive
  1095 functional programs.)  To restore the old behaviour, declare
  1096 
  1097     Delcongs [if_weak_cong];
  1098 
  1099 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1100 complement;
  1101 
  1102 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1103 
  1104 * HOL/datatype: mutual_induct_tac no longer exists --
  1105   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1106 
  1107 * HOL/typedef: fixed type inference for representing set; type
  1108 arguments now have to occur explicitly on the rhs as type constraints;
  1109 
  1110 * ZF: The con_defs part of an inductive definition may no longer refer
  1111 to constants declared in the same theory;
  1112 
  1113 * HOL, ZF: the function mk_cases, generated by the inductive
  1114 definition package, has lost an argument.  To simplify its result, it
  1115 uses the default simpset instead of a supplied list of theorems.
  1116 
  1117 * HOL/List: the constructors of type list are now Nil and Cons;
  1118 
  1119 * Simplifier: the type of the infix ML functions
  1120         setSSolver addSSolver setSolver addSolver
  1121 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1122 for packaging solvers. A solver is created via
  1123         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1124 where the string argument is only a comment.
  1125 
  1126 
  1127 *** Proof tools ***
  1128 
  1129 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1130 decision procedure for linear arithmetic. Currently it is used for
  1131 types `nat', `int', and `real' in HOL (see below); it can, should and
  1132 will be instantiated for other types and logics as well.
  1133 
  1134 * The simplifier now accepts rewrite rules with flexible heads, eg
  1135      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1136   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1137   matching.
  1138 
  1139 
  1140 *** General ***
  1141 
  1142 * New Isabelle/Isar subsystem provides an alternative to traditional
  1143 tactical theorem proving; together with the ProofGeneral/isar user
  1144 interface it offers an interactive environment for developing human
  1145 readable proof documents (Isar == Intelligible semi-automated
  1146 reasoning); for further information see isatool doc isar-ref,
  1147 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1148 
  1149 * improved and simplified presentation of theories: better HTML markup
  1150 (including colors), graph views in several sizes; isatool usedir now
  1151 provides a proper interface for user theories (via -P option); actual
  1152 document preparation based on (PDF)LaTeX is available as well (for
  1153 new-style theories only); see isatool doc system for more information;
  1154 
  1155 * native support for Proof General, both for classic Isabelle and
  1156 Isabelle/Isar;
  1157 
  1158 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1159 using the graph browser tool;
  1160 
  1161 * Isabelle manuals now also available as PDF;
  1162 
  1163 * theory loader rewritten from scratch (may not be fully
  1164 bug-compatible); old loadpath variable has been replaced by show_path,
  1165 add_path, del_path, reset_path functions; new operations such as
  1166 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1167 isatool doc ref);
  1168 
  1169 * improved isatool install: option -k creates KDE application icon,
  1170 option -p DIR installs standalone binaries;
  1171 
  1172 * added ML_PLATFORM setting (useful for cross-platform installations);
  1173 more robust handling of platform specific ML images for SML/NJ;
  1174 
  1175 * the settings environment is now statically scoped, i.e. it is never
  1176 created again in sub-processes invoked from isabelle, isatool, or
  1177 Isabelle;
  1178 
  1179 * path element specification '~~' refers to '$ISABELLE_HOME';
  1180 
  1181 * in locales, the "assumes" and "defines" parts may be omitted if
  1182 empty;
  1183 
  1184 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1185 long arrows);
  1186 
  1187 * new print_mode "HTML";
  1188 
  1189 * new flag show_tags controls display of tags of theorems (which are
  1190 basically just comments that may be attached by some tools);
  1191 
  1192 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1193 mode and goal output format:
  1194 
  1195 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1196 244c244
  1197 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1198 ---
  1199 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1200 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1201 181c181
  1202 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1203 ---
  1204 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1205 
  1206 * function bind_thms stores lists of theorems (cf. bind_thm);
  1207 
  1208 * new shorthand tactics ftac, eatac, datac, fatac;
  1209 
  1210 * qed (and friends) now accept "" as result name; in that case the
  1211 theorem is not stored, but proper checks and presentation of the
  1212 result still apply;
  1213 
  1214 * theorem database now also indexes constants "Trueprop", "all",
  1215 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1216 
  1217 
  1218 *** HOL ***
  1219 
  1220 ** HOL arithmetic **
  1221 
  1222 * There are now decision procedures for linear arithmetic over nat and
  1223 int:
  1224 
  1225 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1226 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1227 are treated as atomic; subformulae not involving type `nat' or `int'
  1228 are ignored; quantified subformulae are ignored unless they are
  1229 positive universal or negative existential. The tactic has to be
  1230 invoked by hand and can be a little bit slow. In particular, the
  1231 running time is exponential in the number of occurrences of `min' and
  1232 `max', and `-' on `nat'.
  1233 
  1234 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1235 (negated) (in)equalities among the premises and the conclusion into
  1236 account (i.e. no compound formulae) and does not know about `min' and
  1237 `max', and `-' on `nat'. It is fast and is used automatically by the
  1238 simplifier.
  1239 
  1240 NB: At the moment, these decision procedures do not cope with mixed
  1241 nat/int formulae where the two parts interact, such as `m < n ==>
  1242 int(m) < int(n)'.
  1243 
  1244 * HOL/Numeral provides a generic theory of numerals (encoded
  1245 efficiently as bit strings); setup for types nat/int/real is in place;
  1246 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1247 int, existing theories and proof scripts may require a few additional
  1248 type constraints;
  1249 
  1250 * integer division and remainder can now be performed on constant
  1251 arguments;
  1252 
  1253 * many properties of integer multiplication, division and remainder
  1254 are now available;
  1255 
  1256 * An interface to the Stanford Validity Checker (SVC) is available through the
  1257 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1258 are proved automatically.  SVC must be installed separately, and its results
  1259 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1260 invocation of the underlying oracle).  For SVC see
  1261   http://verify.stanford.edu/SVC
  1262 
  1263 * IsaMakefile: the HOL-Real target now builds an actual image;
  1264 
  1265 
  1266 ** HOL misc **
  1267 
  1268 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1269 (in Isabelle/Isar) -- by Gertrud Bauer;
  1270 
  1271 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1272 analysis for assembly languages with subtypes;
  1273 
  1274 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1275 -- avoids syntactic ambiguities and treats state, transition, and
  1276 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1277 changed syntax and (many) tactics;
  1278 
  1279 * HOL/inductive: Now also handles more general introduction rules such
  1280   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1281   theorems are now maintained within the theory (maintained via the
  1282   "mono" attribute);
  1283 
  1284 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1285   (using function types) such as
  1286 
  1287   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1288 
  1289 * HOL/record: record_simproc (part of the default simpset) takes care
  1290 of selectors applied to updated records; record_split_tac is no longer
  1291 part of the default claset; update_defs may now be removed from the
  1292 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1293 
  1294   claset_ref () := claset() addSWrapper record_split_wrapper;
  1295   Delsimprocs [record_simproc]
  1296 
  1297 * HOL/typedef: fixed type inference for representing set; type
  1298 arguments now have to occur explicitly on the rhs as type constraints;
  1299 
  1300 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1301 names rather than an ML expression;
  1302 
  1303 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1304 supplied later.  Program schemes can be defined, such as
  1305     "While B C s = (if B s then While B C (C s) else s)"
  1306 where the well-founded relation can be chosen after B and C have been given.
  1307 
  1308 * HOL/List: the constructors of type list are now Nil and Cons;
  1309 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1310 course, ML tools referring to List.list.op # etc. have to be adapted;
  1311 
  1312 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1313 disabled by default; run isabelle with option -m HOL to get back to
  1314 the original Gordon/HOL-style output;
  1315 
  1316 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1317 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1318 
  1319 * HOL basic syntax simplified (more orthogonal): all variants of
  1320 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1321 Eps operator is provided as well: "SOME x. P[x]";
  1322 
  1323 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1324 
  1325 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1326 thus available for user theories;
  1327 
  1328 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1329 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1330 time;
  1331 
  1332 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1333 several times and then mp;
  1334 
  1335 
  1336 *** LK ***
  1337 
  1338 * the notation <<...>> is now available as a notation for sequences of
  1339 formulas;
  1340 
  1341 * the simplifier is now installed
  1342 
  1343 * the axiom system has been generalized (thanks to Soren Heilmann)
  1344 
  1345 * the classical reasoner now has a default rule database
  1346 
  1347 
  1348 *** ZF ***
  1349 
  1350 * new primrec section allows primitive recursive functions to be given
  1351 directly (as in HOL) over datatypes and the natural numbers;
  1352 
  1353 * new tactics induct_tac and exhaust_tac for induction (or case
  1354 analysis) over datatypes and the natural numbers;
  1355 
  1356 * the datatype declaration of type T now defines the recursor T_rec;
  1357 
  1358 * simplification automatically does freeness reasoning for datatype
  1359 constructors;
  1360 
  1361 * automatic type-inference, with AddTCs command to insert new
  1362 type-checking rules;
  1363 
  1364 * datatype introduction rules are now added as Safe Introduction rules
  1365 to the claset;
  1366 
  1367 * the syntax "if P then x else y" is now available in addition to
  1368 if(P,x,y);
  1369 
  1370 
  1371 *** Internal programming interfaces ***
  1372 
  1373 * tuned simplifier trace output; new flag debug_simp;
  1374 
  1375 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1376 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1377 
  1378 * AxClass.axclass_tac lost the theory argument;
  1379 
  1380 * tuned current_goals_markers semantics: begin / end goal avoids
  1381 printing empty lines;
  1382 
  1383 * removed prs and prs_fn hook, which was broken because it did not
  1384 include \n in its semantics, forcing writeln to add one
  1385 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1386 string -> unit if you really want to output text without newline;
  1387 
  1388 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1389 plain output, interface builders may have to enable 'isabelle_font'
  1390 mode to get Isabelle font glyphs as before;
  1391 
  1392 * refined token_translation interface; INCOMPATIBILITY: output length
  1393 now of type real instead of int;
  1394 
  1395 * theory loader actions may be traced via new ThyInfo.add_hook
  1396 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1397 your own database of information attached to *whole* theories -- as
  1398 opposed to intra-theory data slots offered via TheoryDataFun;
  1399 
  1400 * proper handling of dangling sort hypotheses (at last!);
  1401 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1402 extra sort hypotheses that can be witnessed from the type signature;
  1403 the force_strip_shyps flag is gone, any remaining shyps are simply
  1404 left in the theorem (with a warning issued by strip_shyps_warning);
  1405 
  1406 
  1407 
  1408 New in Isabelle98-1 (October 1998)
  1409 ----------------------------------
  1410 
  1411 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1412 
  1413 * several changes of automated proof tools;
  1414 
  1415 * HOL: major changes to the inductive and datatype packages, including
  1416 some minor incompatibilities of theory syntax;
  1417 
  1418 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1419 called `inj_on';
  1420 
  1421 * HOL: removed duplicate thms in Arith:
  1422   less_imp_add_less  should be replaced by  trans_less_add1
  1423   le_imp_add_le      should be replaced by  trans_le_add1
  1424 
  1425 * HOL: unary minus is now overloaded (new type constraints may be
  1426 required);
  1427 
  1428 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1429 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1430 now taken as an integer constant.
  1431 
  1432 * Pure: ML function 'theory_of' renamed to 'theory';
  1433 
  1434 
  1435 *** Proof tools ***
  1436 
  1437 * Simplifier:
  1438   1. Asm_full_simp_tac is now more aggressive.
  1439      1. It will sometimes reorient premises if that increases their power to
  1440         simplify.
  1441      2. It does no longer proceed strictly from left to right but may also
  1442         rotate premises to achieve further simplification.
  1443      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1444      old Asm_full_simp_tac in that it does not rotate premises.
  1445   2. The simplifier now knows a little bit about nat-arithmetic.
  1446 
  1447 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1448 allows for selected deletion of wrappers, by introduction of names for
  1449 wrapper functionals.  This implies that addbefore, addSbefore,
  1450 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1451 and that adding two tactics with the same name overwrites the first
  1452 one (emitting a warning).
  1453   type wrapper = (int -> tactic) -> (int -> tactic)
  1454   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1455   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1456   delWrapper, delSWrapper: claset *  string            -> claset
  1457   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1458 
  1459 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1460 semantics; addbefore now affects only the unsafe part of step_tac
  1461 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1462 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1463 by Force_tac;
  1464 
  1465 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1466 compWrapper; added safe wrapper (and access functions for it);
  1467 
  1468 * HOL/split_all_tac is now much faster and fails if there is nothing
  1469 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1470 and the names of the automatically generated variables have changed.
  1471 split_all_tac has moved within claset() from unsafe wrappers to safe
  1472 wrappers, which means that !!-bound variables are split much more
  1473 aggressively, and safe_tac and clarify_tac now split such variables.
  1474 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1475 Note: the same holds for record_split_tac, which does the job of
  1476 split_all_tac for record fields.
  1477 
  1478 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1479 permanently to the default simpset using Addsplits just like
  1480 Addsimps. They can be removed via Delsplits just like
  1481 Delsimps. Lower-case versions are also available.
  1482 
  1483 * HOL/Simplifier: The rule split_if is now part of the default
  1484 simpset. This means that the simplifier will eliminate all occurrences
  1485 of if-then-else in the conclusion of a goal. To prevent this, you can
  1486 either remove split_if completely from the default simpset by
  1487 `Delsplits [split_if]' or remove it in a specific call of the
  1488 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1489 other case splitting rules to/from the default simpset: every datatype
  1490 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1491 t is the name of the datatype).
  1492 
  1493 * Classical reasoner / Simplifier combination: new force_tac (and
  1494 derivatives Force_tac, force) combines rewriting and classical
  1495 reasoning (and whatever other tools) similarly to auto_tac, but is
  1496 aimed to solve the given subgoal completely.
  1497 
  1498 
  1499 *** General ***
  1500 
  1501 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1502 and `goalw': the theory is no longer needed as an explicit argument -
  1503 the current theory context is used; assumptions are no longer returned
  1504 at the ML-level unless one of them starts with ==> or !!; it is
  1505 recommended to convert to these new commands using isatool fixgoal
  1506 (backup your sources first!);
  1507 
  1508 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1509 the current theory context, and 'theory' to lookup stored theories;
  1510 
  1511 * new theory section 'locale' for declaring constants, assumptions and
  1512 definitions that have local scope;
  1513 
  1514 * new theory section 'nonterminals' for purely syntactic types;
  1515 
  1516 * new theory section 'setup' for generic ML setup functions
  1517 (e.g. package initialization);
  1518 
  1519 * the distribution now includes Isabelle icons: see
  1520 lib/logo/isabelle-{small,tiny}.xpm;
  1521 
  1522 * isatool install - install binaries with absolute references to
  1523 ISABELLE_HOME/bin;
  1524 
  1525 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1526 
  1527 * print mode 'emacs' reserved for Isamode;
  1528 
  1529 * support multiple print (ast) translations per constant name;
  1530 
  1531 * theorems involving oracles are now printed with a suffixed [!];
  1532 
  1533 
  1534 *** HOL ***
  1535 
  1536 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1537 
  1538 * HOL/inductive package reorganized and improved: now supports mutual
  1539 definitions such as
  1540 
  1541   inductive EVEN ODD
  1542     intrs
  1543       null "0 : EVEN"
  1544       oddI "n : EVEN ==> Suc n : ODD"
  1545       evenI "n : ODD ==> Suc n : EVEN"
  1546 
  1547 new theorem list "elims" contains an elimination rule for each of the
  1548 recursive sets; inductive definitions now handle disjunctive premises
  1549 correctly (also ZF);
  1550 
  1551 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1552 "mutual_induct" no longer exists - the induction rule is always
  1553 contained in "induct";
  1554 
  1555 
  1556 * HOL/datatype package re-implemented and greatly improved: now
  1557 supports mutually recursive datatypes such as
  1558 
  1559   datatype
  1560     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1561             | SUM ('a aexp) ('a aexp)
  1562             | DIFF ('a aexp) ('a aexp)
  1563             | NUM 'a
  1564   and
  1565     'a bexp = LESS ('a aexp) ('a aexp)
  1566             | AND ('a bexp) ('a bexp)
  1567             | OR ('a bexp) ('a bexp)
  1568 
  1569 as well as indirectly recursive datatypes such as
  1570 
  1571   datatype
  1572     ('a, 'b) term = Var 'a
  1573                   | App 'b ((('a, 'b) term) list)
  1574 
  1575 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1576 induction on mutually / indirectly recursive datatypes.
  1577 
  1578 Primrec equations are now stored in theory and can be accessed via
  1579 <function_name>.simps.
  1580 
  1581 INCOMPATIBILITIES:
  1582 
  1583   - Theories using datatypes must now have theory Datatype as an
  1584     ancestor.
  1585   - The specific <typename>.induct_tac no longer exists - use the
  1586     generic induct_tac instead.
  1587   - natE has been renamed to nat.exhaust - use exhaust_tac
  1588     instead of res_inst_tac ... natE. Note that the variable
  1589     names in nat.exhaust differ from the names in natE, this
  1590     may cause some "fragile" proofs to fail.
  1591   - The theorems split_<typename>_case and split_<typename>_case_asm
  1592     have been renamed to <typename>.split and <typename>.split_asm.
  1593   - Since default sorts of type variables are now handled correctly,
  1594     some datatype definitions may have to be annotated with explicit
  1595     sort constraints.
  1596   - Primrec definitions no longer require function name and type
  1597     of recursive argument.
  1598 
  1599 Consider using isatool fixdatatype to adapt your theories and proof
  1600 scripts to the new package (backup your sources first!).
  1601 
  1602 
  1603 * HOL/record package: considerably improved implementation; now
  1604 includes concrete syntax for record types, terms, updates; theorems
  1605 for surjective pairing and splitting !!-bound record variables; proof
  1606 support is as follows:
  1607 
  1608   1) standard conversions (selectors or updates applied to record
  1609 constructor terms) are part of the standard simpset;
  1610 
  1611   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1612 made part of standard simpset and claset via addIffs;
  1613 
  1614   3) a tactic for record field splitting (record_split_tac) is part of
  1615 the standard claset (addSWrapper);
  1616 
  1617 To get a better idea about these rules you may retrieve them via
  1618 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1619 the name of your record type.
  1620 
  1621 The split tactic 3) conceptually simplifies by the following rule:
  1622 
  1623   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1624 
  1625 Thus any record variable that is bound by meta-all will automatically
  1626 blow up into some record constructor term, consequently the
  1627 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1628 solve record problems automatically.
  1629 
  1630 
  1631 * reorganized the main HOL image: HOL/Integ and String loaded by
  1632 default; theory Main includes everything;
  1633 
  1634 * automatic simplification of integer sums and comparisons, using cancellation;
  1635 
  1636 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1637 
  1638 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1639 
  1640 * many new identities for unions, intersections, set difference, etc.;
  1641 
  1642 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1643 called split_if, split_split, split_sum_case and split_nat_case (to go
  1644 with add/delsplits);
  1645 
  1646 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1647 (?x::unit) = (); this is made part of the default simpset, which COULD
  1648 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1649 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1650 unit_abs_eta_conv is added in order to counter the effect of
  1651 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1652 %u.f();
  1653 
  1654 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1655 makes more sense);
  1656 
  1657 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1658   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1659   disjointness reasoning but breaking a few old proofs.
  1660 
  1661 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1662 to 'converse' from 'inverse' (for compatibility with ZF and some
  1663 literature);
  1664 
  1665 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1666 the well-founded relation;
  1667 
  1668 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1669     Compl A.  The "Compl" syntax remains available as input syntax for this
  1670     release ONLY.
  1671 
  1672 * HOL/Update: new theory of function updates:
  1673     f(a:=b) == %x. if x=a then b else f x
  1674 may also be iterated as in f(a:=b,c:=d,...);
  1675 
  1676 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1677 
  1678 * HOL/List:
  1679   - new function list_update written xs[i:=v] that updates the i-th
  1680     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1681   - new function `upt' written [i..j(] which generates the list
  1682     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1683     bound write [i..j], which is a shorthand for [i..j+1(].
  1684   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1685 
  1686 * HOL/Arith:
  1687   - removed 'pred' (predecessor) function;
  1688   - generalized some theorems about n-1;
  1689   - many new laws about "div" and "mod";
  1690   - new laws about greatest common divisors (see theory ex/Primes);
  1691 
  1692 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1693 instead of "inverse";
  1694 
  1695 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1696   of the multiset ordering;
  1697 
  1698 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1699   (not included by default);
  1700 
  1701 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1702 
  1703 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1704   programs, i.e. different program variables may have different types.
  1705 
  1706 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1707   [previously, this check worked only if the rewrite rule was unconditional]
  1708   Now rew can involve either definitions or equalities (either == or =).
  1709 
  1710 
  1711 *** ZF ***
  1712 
  1713 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1714   only the theorems proved on ZF.ML;
  1715 
  1716 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1717   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1718   disjointness reasoning but breaking a few old proofs.
  1719 
  1720 * ZF/Update: new theory of function updates
  1721     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1722   may also be iterated as in f(a:=b,c:=d,...);
  1723 
  1724 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1725 
  1726 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1727   [previously, this check worked only if the rewrite rule was unconditional]
  1728   Now rew can involve either definitions or equalities (either == or =).
  1729 
  1730 * case_tac provided for compatibility with HOL
  1731     (like the old excluded_middle_tac, but with subgoals swapped)
  1732 
  1733 
  1734 *** Internal programming interfaces ***
  1735 
  1736 * Pure: several new basic modules made available for general use, see
  1737 also src/Pure/README;
  1738 
  1739 * improved the theory data mechanism to support encapsulation (data
  1740 kind name replaced by private Object.kind, acting as authorization
  1741 key); new type-safe user interface via functor TheoryDataFun; generic
  1742 print_data function becomes basically useless;
  1743 
  1744 * removed global_names compatibility flag -- all theory declarations
  1745 are qualified by default;
  1746 
  1747 * module Pure/Syntax now offers quote / antiquote translation
  1748 functions (useful for Hoare logic etc. with implicit dependencies);
  1749 see HOL/ex/Antiquote for an example use;
  1750 
  1751 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1752 cterm -> thm;
  1753 
  1754 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1755 subgoal;
  1756 
  1757 * Display.print_goals function moved to Locale.print_goals;
  1758 
  1759 * standard print function for goals supports current_goals_markers
  1760 variable for marking begin of proof, end of proof, start of goal; the
  1761 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1762 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1763 for example;
  1764 
  1765 
  1766 
  1767 New in Isabelle98 (January 1998)
  1768 --------------------------------
  1769 
  1770 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1771 
  1772 * changed lexical syntax of terms / types: dots made part of long
  1773 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1774 
  1775 * simpset (and claset) reference variable replaced by functions
  1776 simpset / simpset_ref;
  1777 
  1778 * no longer supports theory aliases (via merge) and non-trivial
  1779 implicit merge of thms' signatures;
  1780 
  1781 * most internal names of constants changed due to qualified names;
  1782 
  1783 * changed Pure/Sequence interface (see Pure/seq.ML);
  1784 
  1785 
  1786 *** General Changes ***
  1787 
  1788 * hierachically structured name spaces (for consts, types, axms, thms
  1789 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1790 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1791 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1792 long_names for fully qualified output names; NOTE: ML programs
  1793 (special tactics, packages etc.) referring to internal names may have
  1794 to be adapted to cope with fully qualified names; in case of severe
  1795 backward campatibility problems try setting 'global_names' at compile
  1796 time to have enrything declared within a flat name space; one may also
  1797 fine tune name declarations in theories via the 'global' and 'local'
  1798 section;
  1799 
  1800 * reimplemented the implicit simpset and claset using the new anytype
  1801 data filed in signatures; references simpset:simpset ref etc. are
  1802 replaced by functions simpset:unit->simpset and
  1803 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1804 to patch your ML files accordingly;
  1805 
  1806 * HTML output now includes theory graph data for display with Java
  1807 applet or isatool browser; data generated automatically via isatool
  1808 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1809 
  1810 * defs may now be conditional; improved rewrite_goals_tac to handle
  1811 conditional equations;
  1812 
  1813 * defs now admits additional type arguments, using TYPE('a) syntax;
  1814 
  1815 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1816 creates a new theory node; implicit merge of thms' signatures is
  1817 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1818 transfer:theory->thm->thm in (rare) cases;
  1819 
  1820 * improved handling of draft signatures / theories; draft thms (and
  1821 ctyps, cterms) are automatically promoted to real ones;
  1822 
  1823 * slightly changed interfaces for oracles: admit many per theory, named
  1824 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1825 
  1826 * print_goals: optional output of const types (set show_consts and
  1827 show_types);
  1828 
  1829 * improved output of warnings (###) and errors (***);
  1830 
  1831 * subgoal_tac displays a warning if the new subgoal has type variables;
  1832 
  1833 * removed old README and Makefiles;
  1834 
  1835 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1836 
  1837 * removed obsolete init_pps and init_database;
  1838 
  1839 * deleted the obsolete tactical STATE, which was declared by
  1840     fun STATE tacfun st = tacfun st st;
  1841 
  1842 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1843 (which abbreviates $HOME);
  1844 
  1845 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1846 use isatool fixseq to adapt your ML programs (this works for fully
  1847 qualified references to the Sequence structure only!);
  1848 
  1849 * use_thy no longer requires writable current directory; it always
  1850 reloads .ML *and* .thy file, if either one is out of date;
  1851 
  1852 
  1853 *** Classical Reasoner ***
  1854 
  1855 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1856 tactics that use classical reasoning to simplify a subgoal without
  1857 splitting it into several subgoals;
  1858 
  1859 * Safe_tac: like safe_tac but uses the default claset;
  1860 
  1861 
  1862 *** Simplifier ***
  1863 
  1864 * added simplification meta rules:
  1865     (asm_)(full_)simplify: simpset -> thm -> thm;
  1866 
  1867 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1868 logics (again);
  1869 
  1870 * added prems argument to simplification procedures;
  1871 
  1872 * HOL, FOL, ZF: added infix function `addsplits':
  1873   instead of `<simpset> setloop (split_tac <thms>)'
  1874   you can simply write `<simpset> addsplits <thms>'
  1875 
  1876 
  1877 *** Syntax ***
  1878 
  1879 * TYPE('a) syntax for type reflection terms;
  1880 
  1881 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1882 
  1883 * pretty printer: changed order of mixfix annotation preference (again!);
  1884 
  1885 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1886 
  1887 
  1888 *** HOL ***
  1889 
  1890 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1891   with `addloop' of the simplifier to faciliate case splitting in premises.
  1892 
  1893 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1894 
  1895 * HOL/Auth: new protocol proofs including some for the Internet
  1896   protocol TLS;
  1897 
  1898 * HOL/Map: new theory of `maps' a la VDM;
  1899 
  1900 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1901 cancelling out common nat summands from =, <, <= (in)equalities, or
  1902 differences; simplification procedures nat_cancel_factor for
  1903 cancelling common factor from =, <, <= (in)equalities over natural
  1904 sums; nat_cancel contains both kinds of procedures, it is installed by
  1905 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1906 
  1907 * HOL/simplifier: terms of the form
  1908   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1909   are rewritten to
  1910   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1911   and those of the form
  1912   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1913   are rewritten to
  1914   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1915 
  1916 * HOL/datatype
  1917   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1918 
  1919   P(t_case f1 ... fn x) =
  1920      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1921         ...
  1922        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1923      )
  1924 
  1925   and a theorem `split_t_case_asm' of the form
  1926 
  1927   P(t_case f1 ... fn x) =
  1928     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1929         ...
  1930        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1931      )
  1932   which can be added to a simpset via `addsplits'. The existing theorems
  1933   expand_list_case and expand_option_case have been renamed to
  1934   split_list_case and split_option_case.
  1935 
  1936 * HOL/Arithmetic:
  1937   - `pred n' is automatically converted to `n-1'.
  1938     Users are strongly encouraged not to use `pred' any longer,
  1939     because it will disappear altogether at some point.
  1940   - Users are strongly encouraged to write "0 < n" rather than
  1941     "n ~= 0". Theorems and proof tools have been modified towards this
  1942     `standard'.
  1943 
  1944 * HOL/Lists:
  1945   the function "set_of_list" has been renamed "set" (and its theorems too);
  1946   the function "nth" now takes its arguments in the reverse order and
  1947   has acquired the infix notation "!" as in "xs!n".
  1948 
  1949 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1950 
  1951 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1952   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1953 
  1954 * HOL/record: extensible records with schematic structural subtyping
  1955 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1956 still lacks various theorems and concrete record syntax;
  1957 
  1958 
  1959 *** HOLCF ***
  1960 
  1961 * removed "axioms" and "generated by" sections;
  1962 
  1963 * replaced "ops" section by extended "consts" section, which is capable of
  1964   handling the continuous function space "->" directly;
  1965 
  1966 * domain package:
  1967   . proves theorems immediately and stores them in the theory,
  1968   . creates hierachical name space,
  1969   . now uses normal mixfix annotations (instead of cinfix...),
  1970   . minor changes to some names and values (for consistency),
  1971   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1972   . separator between mutual domain defs: changed "," to "and",
  1973   . improved handling of sort constraints;  now they have to
  1974     appear on the left-hand side of the equations only;
  1975 
  1976 * fixed LAM <x,y,zs>.b syntax;
  1977 
  1978 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1979 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1980 
  1981 
  1982 *** FOL and ZF ***
  1983 
  1984 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1985   with `addloop' of the simplifier to faciliate case splitting in premises.
  1986 
  1987 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1988 in HOL, they strip ALL and --> from proved theorems;
  1989 
  1990 
  1991 
  1992 New in Isabelle94-8 (May 1997)
  1993 ------------------------------
  1994 
  1995 *** General Changes ***
  1996 
  1997 * new utilities to build / run / maintain Isabelle etc. (in parts
  1998 still somewhat experimental); old Makefiles etc. still functional;
  1999 
  2000 * new 'Isabelle System Manual';
  2001 
  2002 * INSTALL text, together with ./configure and ./build scripts;
  2003 
  2004 * reimplemented type inference for greater efficiency, better error
  2005 messages and clean internal interface;
  2006 
  2007 * prlim command for dealing with lots of subgoals (an easier way of
  2008 setting goals_limit);
  2009 
  2010 
  2011 *** Syntax ***
  2012 
  2013 * supports alternative (named) syntax tables (parser and pretty
  2014 printer); internal interface is provided by add_modesyntax(_i);
  2015 
  2016 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2017 be used in conjunction with the Isabelle symbol font; uses the
  2018 "symbols" syntax table;
  2019 
  2020 * added token_translation interface (may translate name tokens in
  2021 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2022 the current print_mode); IMPORTANT: user print translation functions
  2023 are responsible for marking newly introduced bounds
  2024 (Syntax.mark_boundT);
  2025 
  2026 * token translations for modes "xterm" and "xterm_color" that display
  2027 names in bold, underline etc. or colors (which requires a color
  2028 version of xterm);
  2029 
  2030 * infixes may now be declared with names independent of their syntax;
  2031 
  2032 * added typed_print_translation (like print_translation, but may
  2033 access type of constant);
  2034 
  2035 
  2036 *** Classical Reasoner ***
  2037 
  2038 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2039 some limitations.  Blast_tac...
  2040   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2041   + ignores elimination rules that don't have the correct format
  2042         (the conclusion MUST be a formula variable)
  2043   + ignores types, which can make HOL proofs fail
  2044   + rules must not require higher-order unification, e.g. apply_type in ZF
  2045     [message "Function Var's argument not a bound variable" relates to this]
  2046   + its proof strategy is more general but can actually be slower
  2047 
  2048 * substitution with equality assumptions no longer permutes other
  2049 assumptions;
  2050 
  2051 * minor changes in semantics of addafter (now called addaltern); renamed
  2052 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2053 (and access functions for it);
  2054 
  2055 * improved combination of classical reasoner and simplifier:
  2056   + functions for handling clasimpsets
  2057   + improvement of addss: now the simplifier is called _after_ the
  2058     safe steps.
  2059   + safe variant of addss called addSss: uses safe simplifications
  2060     _during_ the safe steps. It is more complete as it allows multiple
  2061     instantiations of unknowns (e.g. with slow_tac).
  2062 
  2063 *** Simplifier ***
  2064 
  2065 * added interface for simplification procedures (functions that
  2066 produce *proven* rewrite rules on the fly, depending on current
  2067 redex);
  2068 
  2069 * ordering on terms as parameter (used for ordered rewriting);
  2070 
  2071 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2072 
  2073 * the solver is now split into a safe and an unsafe part.
  2074 This should be invisible for the normal user, except that the
  2075 functions setsolver and addsolver have been renamed to setSolver and
  2076 addSolver; added safe_asm_full_simp_tac;
  2077 
  2078 
  2079 *** HOL ***
  2080 
  2081 * a generic induction tactic `induct_tac' which works for all datatypes and
  2082 also for type `nat';
  2083 
  2084 * a generic case distinction tactic `exhaust_tac' which works for all
  2085 datatypes and also for type `nat';
  2086 
  2087 * each datatype comes with a function `size';
  2088 
  2089 * patterns in case expressions allow tuple patterns as arguments to
  2090 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2091 
  2092 * primrec now also works with type nat;
  2093 
  2094 * recdef: a new declaration form, allows general recursive functions to be
  2095 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2096 
  2097 * the constant for negation has been renamed from "not" to "Not" to
  2098 harmonize with FOL, ZF, LK, etc.;
  2099 
  2100 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2101 infinite lists;
  2102 
  2103 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2104 
  2105 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2106 problems in commutative rings, using axiomatic type classes for + and *;
  2107 
  2108 * more examples in HOL/MiniML and HOL/Auth;
  2109 
  2110 * more default rewrite rules for quantifiers, union/intersection;
  2111 
  2112 * a new constant `arbitrary == @x.False';
  2113 
  2114 * HOLCF/IOA replaces old HOL/IOA;
  2115 
  2116 * HOLCF changes: derived all rules and arities
  2117   + axiomatic type classes instead of classes
  2118   + typedef instead of faking type definitions
  2119   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2120   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2121   + eliminated the types void, one, tr
  2122   + use unit lift and bool lift (with translations) instead of one and tr
  2123   + eliminated blift from Lift3.thy (use Def instead of blift)
  2124   all eliminated rules are derived as theorems --> no visible changes ;
  2125 
  2126 
  2127 *** ZF ***
  2128 
  2129 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2130 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2131 as ZF_cs addSIs [equalityI];
  2132 
  2133 
  2134 
  2135 New in Isabelle94-7 (November 96)
  2136 ---------------------------------
  2137 
  2138 * allowing negative levels (as offsets) in prlev and choplev;
  2139 
  2140 * super-linear speedup for large simplifications;
  2141 
  2142 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2143 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2144 FAIL); can suppress it using the command Delsimps (ex_simps @
  2145 all_simps); De Morgan laws are also now included, by default;
  2146 
  2147 * improved printing of ==>  :  ~:
  2148 
  2149 * new object-logic "Sequents" adds linear logic, while replacing LK
  2150 and Modal (thanks to Sara Kalvala);
  2151 
  2152 * HOL/Auth: correctness proofs for authentication protocols;
  2153 
  2154 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2155 examples on HOL/Auth);
  2156 
  2157 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2158 the rewriter and classical reasoner simultaneously;
  2159 
  2160 * function uresult no longer returns theorems in "standard" format;
  2161 regain previous version by: val uresult = standard o uresult;
  2162 
  2163 
  2164 
  2165 New in Isabelle94-6
  2166 -------------------
  2167 
  2168 * oracles -- these establish an interface between Isabelle and trusted
  2169 external reasoners, which may deliver results as theorems;
  2170 
  2171 * proof objects (in particular record all uses of oracles);
  2172 
  2173 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2174 
  2175 * "constdefs" section in theory files;
  2176 
  2177 * "primrec" section (HOL) no longer requires names;
  2178 
  2179 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2180 
  2181 
  2182 
  2183 New in Isabelle94-5
  2184 -------------------
  2185 
  2186 * reduced space requirements;
  2187 
  2188 * automatic HTML generation from theories;
  2189 
  2190 * theory files no longer require "..." (quotes) around most types;
  2191 
  2192 * new examples, including two proofs of the Church-Rosser theorem;
  2193 
  2194 * non-curried (1994) version of HOL is no longer distributed;
  2195 
  2196 
  2197 
  2198 New in Isabelle94-4
  2199 -------------------
  2200 
  2201 * greatly reduced space requirements;
  2202 
  2203 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2204 
  2205 * searchable theorem database (see the section "Retrieving theorems" on
  2206 page 8 of the Reference Manual);
  2207 
  2208 * new examples, including Grabczewski's monumental case study of the
  2209 Axiom of Choice;
  2210 
  2211 * The previous version of HOL renamed to Old_HOL;
  2212 
  2213 * The new version of HOL (previously called CHOL) uses a curried syntax
  2214 for functions.  Application looks like f a b instead of f(a,b);
  2215 
  2216 * Mutually recursive inductive definitions finally work in HOL;
  2217 
  2218 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2219 translates to the operator "split";
  2220 
  2221 
  2222 
  2223 New in Isabelle94-3
  2224 -------------------
  2225 
  2226 * new infix operator, addss, allowing the classical reasoner to
  2227 perform simplification at each step of its search.  Example:
  2228         fast_tac (cs addss ss)
  2229 
  2230 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2231 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2232 look like (a,b) instead of <a,b>;
  2233 
  2234 * PLEASE NOTE: CHOL will eventually replace HOL!
  2235 
  2236 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2237 It translates to the operator "split".  A new theory of integers is available;
  2238 
  2239 * In ZF, integer numerals now denote two's-complement binary integers.
  2240 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2241 
  2242 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2243 of the Axiom of Choice;
  2244 
  2245 
  2246 
  2247 New in Isabelle94-2
  2248 -------------------
  2249 
  2250 * Significantly faster resolution;
  2251 
  2252 * the different sections in a .thy file can now be mixed and repeated
  2253 freely;
  2254 
  2255 * Database of theorems for FOL, HOL and ZF.  New
  2256 commands including qed, qed_goal and bind_thm store theorems in the database.
  2257 
  2258 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2259 a given theory (thms_of), or find out what theory a theorem was proved in
  2260 (theory_of_thm);
  2261 
  2262 * Bugs fixed in the inductive definition and datatype packages;
  2263 
  2264 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2265 and HOL_dup_cs obsolete;
  2266 
  2267 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2268 have been removed;
  2269 
  2270 * Simpler definition of function space in ZF;
  2271 
  2272 * new results about cardinal and ordinal arithmetic in ZF;
  2273 
  2274 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2275 types;
  2276 
  2277 
  2278 $Id$