NEWS
author nipkow
Fri Aug 23 11:08:01 2002 +0200 (2002-08-23)
changeset 13518 a0749ce05100
parent 13500 2222c7a0e8bb
child 13522 934fffeb6f38
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 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands are
    59   distributed over a sum of terms.
    60 
    61 
    62 *** ML ***
    63 
    64 * Pure: Tactic.prove provides sane interface for internal proofs;
    65 omits the infamous "standard" operation, so this is more appropriate
    66 than prove_goalw_cterm in many situations (e.g. in simprocs);
    67 
    68 * Pure: improved error reporting of simprocs;
    69 
    70 * Provers: Simplifier.simproc(_i) provides sane interface for setting
    71 up simprocs;
    72 
    73 
    74 
    75 New in Isabelle2002 (March 2002)
    76 --------------------------------
    77 
    78 *** Document preparation ***
    79 
    80 * greatly simplified document preparation setup, including more
    81 graceful interpretation of isatool usedir -i/-d/-D options, and more
    82 instructive isatool mkdir; users should basically be able to get
    83 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    84 users may run a separate document processing stage manually like this:
    85 "isatool usedir -D output HOL Test && isatool document Test/output";
    86 
    87 * theory dependency graph may now be incorporated into documents;
    88 isatool usedir -g true will produce session_graph.eps/.pdf for use
    89 with \includegraphics of LaTeX;
    90 
    91 * proper spacing of consecutive markup elements, especially text
    92 blocks after section headings;
    93 
    94 * support bold style (for single symbols only), input syntax is like
    95 this: "\<^bold>\<alpha>" or "\<^bold>A";
    96 
    97 * \<bullet> is now output as bold \cdot by default, which looks much
    98 better in printed text;
    99 
   100 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   101 note that these symbols are currently unavailable in Proof General /
   102 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   103 
   104 * isatool latex no longer depends on changed TEXINPUTS, instead
   105 isatool document copies the Isabelle style files to the target
   106 location;
   107 
   108 
   109 *** Isar ***
   110 
   111 * Pure/Provers: improved proof by cases and induction;
   112   - 'case' command admits impromptu naming of parameters (such as
   113     "case (Suc n)");
   114   - 'induct' method divinates rule instantiation from the inductive
   115     claim; no longer requires excessive ?P bindings for proper
   116     instantiation of cases;
   117   - 'induct' method properly enumerates all possibilities of set/type
   118     rules; as a consequence facts may be also passed through *type*
   119     rules without further ado;
   120   - 'induct' method now derives symbolic cases from the *rulified*
   121     rule (before it used to rulify cases stemming from the internal
   122     atomized version); this means that the context of a non-atomic
   123     statement becomes is included in the hypothesis, avoiding the
   124     slightly cumbersome show "PROP ?case" form;
   125   - 'induct' may now use elim-style induction rules without chaining
   126     facts, using ``missing'' premises from the goal state; this allows
   127     rules stemming from inductive sets to be applied in unstructured
   128     scripts, while still benefitting from proper handling of non-atomic
   129     statements; NB: major inductive premises need to be put first, all
   130     the rest of the goal is passed through the induction;
   131   - 'induct' proper support for mutual induction involving non-atomic
   132     rule statements (uses the new concept of simultaneous goals, see
   133     below);
   134   - append all possible rule selections, but only use the first
   135     success (no backtracking);
   136   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   137   - undeclared rule case names default to numbers 1, 2, 3, ...;
   138   - added 'print_induct_rules' (covered by help item in recent Proof
   139     General versions);
   140   - moved induct/cases attributes to Pure, methods to Provers;
   141   - generic method setup instantiated for FOL and HOL;
   142 
   143 * Pure: support multiple simultaneous goal statements, for example
   144 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   145 meta-level mechanism, this acts as if several individual goals had
   146 been stated separately; in particular common proof methods need to be
   147 repeated in order to cover all claims; note that a single elimination
   148 step is *not* sufficient to establish the two conjunctions, so this
   149 fails:
   150 
   151   assume "A & B" then have A and B ..   (*".." fails*)
   152 
   153 better use "obtain" in situations as above; alternative refer to
   154 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   155 
   156 * Pure: proper integration with ``locales''; unlike the original
   157 version by Florian Kammüller, Isar locales package high-level proof
   158 contexts rather than raw logical ones (e.g. we admit to include
   159 attributes everywhere); operations on locales include merge and
   160 rename; support for implicit arguments (``structures''); simultaneous
   161 type-inference over imports and text; see also HOL/ex/Locales.thy for
   162 some examples;
   163 
   164 * Pure: the following commands have been ``localized'', supporting a
   165 target locale specification "(in name)": 'lemma', 'theorem',
   166 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   167 stored both within the locale and at the theory level (exported and
   168 qualified by the locale name);
   169 
   170 * Pure: theory goals may now be specified in ``long'' form, with
   171 ad-hoc contexts consisting of arbitrary locale elements. for example
   172 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   173 definitions may be given, too); the result is a meta-level rule with
   174 the context elements being discharged in the obvious way;
   175 
   176 * Pure: new proof command 'using' allows to augment currently used
   177 facts after a goal statement ('using' is syntactically analogous to
   178 'apply', but acts on the goal's facts only); this allows chained facts
   179 to be separated into parts given before and after a claim, as in
   180 ``from a and b have C using d and e <proof>'';
   181 
   182 * Pure: renamed "antecedent" case to "rule_context";
   183 
   184 * Pure: new 'judgment' command records explicit information about the
   185 object-logic embedding (used by several tools internally); no longer
   186 use hard-wired "Trueprop";
   187 
   188 * Pure: added 'corollary' command;
   189 
   190 * Pure: fixed 'token_translation' command;
   191 
   192 * Pure: removed obsolete 'exported' attribute;
   193 
   194 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   195 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   196 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   197 
   198 * Pure: method 'atomize' presents local goal premises as object-level
   199 statements (atomic meta-level propositions); setup controlled via
   200 rewrite rules declarations of 'atomize' attribute; example
   201 application: 'induct' method with proper rule statements in improper
   202 proof *scripts*;
   203 
   204 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   205 now consider the syntactic context of assumptions, giving a better
   206 chance to get type-inference of the arguments right (this is
   207 especially important for locales);
   208 
   209 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   210 mode;
   211 
   212 * Pure/obtain: the formal conclusion "thesis", being marked as
   213 ``internal'', may no longer be reference directly in the text;
   214 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   215 situations;
   216 
   217 * Pure: generic 'sym' attribute which declares a rule both as pure
   218 'elim?' and for the 'symmetric' operation;
   219 
   220 * Pure: marginal comments ``--'' may now occur just anywhere in the
   221 text; the fixed correlation with particular command syntax has been
   222 discontinued;
   223 
   224 * Pure: new method 'rules' is particularly well-suited for proof
   225 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   226 but often produces more compact proof terms with less detours;
   227 
   228 * Pure/Provers/classical: simplified integration with pure rule
   229 attributes and methods; the classical "intro?/elim?/dest?"
   230 declarations coincide with the pure ones; the "rule" method no longer
   231 includes classically swapped intros; "intro" and "elim" methods no
   232 longer pick rules from the context; also got rid of ML declarations
   233 AddXIs/AddXEs/AddXDs; all of this has some potential for
   234 INCOMPATIBILITY;
   235 
   236 * Provers/classical: attribute 'swapped' produces classical inversions
   237 of introduction rules;
   238 
   239 * Provers/simplifier: 'simplified' attribute may refer to explicit
   240 rules instead of full simplifier context; 'iff' attribute handles
   241 conditional rules;
   242 
   243 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   244 
   245 * HOL: 'recdef' now fails on unfinished automated proofs, use
   246 "(permissive)" option to recover old behavior;
   247 
   248 * HOL: 'inductive' no longer features separate (collective) attributes
   249 for 'intros' (was found too confusing);
   250 
   251 * HOL: properly declared induction rules less_induct and
   252 wf_induct_rule;
   253 
   254 
   255 *** HOL ***
   256 
   257 * HOL: moved over to sane numeral syntax; the new policy is as
   258 follows:
   259 
   260   - 0 and 1 are polymorphic constants, which are defined on any
   261   numeric type (nat, int, real etc.);
   262 
   263   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   264   binary representation internally;
   265 
   266   - type nat has special constructor Suc, and generally prefers Suc 0
   267   over 1::nat and Suc (Suc 0) over 2::nat;
   268 
   269 This change may cause significant problems of INCOMPATIBILITY; here
   270 are some hints on converting existing sources:
   271 
   272   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   273   entities, so expressions involving "-" (unary or binary minus) need
   274   to be spaced properly;
   275 
   276   - existing occurrences of "1" may need to be constraint "1::nat" or
   277   even replaced by Suc 0; similar for old "2";
   278 
   279   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   280 
   281   - remove all special provisions on numerals in proofs;
   282 
   283 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   284 representation (depends on bin_arith_simps in the default context);
   285 
   286 * HOL: symbolic syntax for x^2 (numeral 2);
   287 
   288 * HOL: the class of all HOL types is now called "type" rather than
   289 "term"; INCOMPATIBILITY, need to adapt references to this type class
   290 in axclass/classes, instance/arities, and (usually rare) occurrences
   291 in typings (of consts etc.); internally the class is called
   292 "HOL.type", ML programs should refer to HOLogic.typeS;
   293 
   294 * HOL/record package improvements:
   295   - new derived operations "fields" to build a partial record section,
   296     "extend" to promote a fixed record to a record scheme, and
   297     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   298     declared as simp by default;
   299   - shared operations ("more", "fields", etc.) now need to be always
   300     qualified) --- potential INCOMPATIBILITY;
   301   - removed "make_scheme" operations (use "make" with "extend") --
   302     INCOMPATIBILITY;
   303   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   304   - provides cases/induct rules for use with corresponding Isar
   305     methods (for concrete records, record schemes, concrete more
   306     parts, and schematic more parts -- in that order);
   307   - internal definitions directly based on a light-weight abstract
   308     theory of product types over typedef rather than datatype;
   309 
   310 * HOL: generic code generator for generating executable ML code from
   311 specifications; specific support for HOL constructs such as inductive
   312 datatypes and sets, as well as recursive functions; can be invoked
   313 via 'generate_code' theory section;
   314 
   315 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   316 
   317 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   318 (beware of argument permutation!);
   319 
   320 * HOL: linorder_less_split superseded by linorder_cases;
   321 
   322 * HOL/List: "nodups" renamed to "distinct";
   323 
   324 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   325 to peripheral theory "Hilbert_Choice";
   326 
   327 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   328 in this (rare) case use:
   329 
   330   delSWrapper "split_all_tac"
   331   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   332 
   333 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   334 MAY FAIL;
   335 
   336 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   337 Isabelle's type classes, ^ on functions and relations has too general
   338 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   339 necessary to attach explicit type constraints;
   340 
   341 * HOL/Relation: the prefix name of the infix "O" has been changed from
   342 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   343 renamed accordingly (eg "compI" -> "rel_compI").
   344 
   345 * HOL: syntax translations now work properly with numerals and records
   346 expressions;
   347 
   348 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   349 of "lam" -- INCOMPATIBILITY;
   350 
   351 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   352 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   353 renamed "Product_Type.unit";
   354 
   355 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   356 
   357 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   358 the "cases" method);
   359 
   360 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   361 Florian Kammüller);
   362 
   363 * HOL/IMP: updated and converted to new-style theory format; several
   364 parts turned into readable document, with proper Isar proof texts and
   365 some explanations (by Gerwin Klein);
   366 
   367 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   368 
   369 * HOL-Hyperreal is now a logic image;
   370 
   371 
   372 *** HOLCF ***
   373 
   374 * Isar: consts/constdefs supports mixfix syntax for continuous
   375 operations;
   376 
   377 * Isar: domain package adapted to new-style theory format, e.g. see
   378 HOLCF/ex/Dnat.thy;
   379 
   380 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   381 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   382 lift.induct_tac, always use UU instead of Undef;
   383 
   384 * HOLCF/IMP: updated and converted to new-style theory;
   385 
   386 
   387 *** ZF ***
   388 
   389 * Isar: proper integration of logic-specific tools and packages,
   390 including theory commands '(co)inductive', '(co)datatype',
   391 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   392 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   393 
   394 * theory Main no longer includes AC; for the Axiom of Choice, base
   395 your theory on Main_ZFC;
   396 
   397 * the integer library now covers quotients and remainders, with many
   398 laws relating division to addition, multiplication, etc.;
   399 
   400 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   401 typeless version of the formalism;
   402 
   403 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   404 format;
   405 
   406 * ZF/Induct: new directory for examples of inductive definitions,
   407 including theory Multiset for multiset orderings; converted to
   408 new-style theory format;
   409 
   410 * ZF: many new theorems about lists, ordinals, etc.;
   411 
   412 
   413 *** General ***
   414 
   415 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   416 variable proof controls level of detail: 0 = no proofs (only oracle
   417 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   418 also ref manual for further ML interfaces;
   419 
   420 * Pure/axclass: removed obsolete ML interface
   421 goal_subclass/goal_arity;
   422 
   423 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   424 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   425 separate tokens, so expressions involving minus need to be spaced
   426 properly;
   427 
   428 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   429 rather than "infixl" or "infixr";
   430 
   431 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   432 sort constraint specifications in type inference; e.g. "x::_::foo"
   433 ensures that the type of "x" is of sort "foo" (but not necessarily a
   434 type variable);
   435 
   436 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   437 control output of nested => (types); the default behavior is
   438 "type_brackets";
   439 
   440 * Pure/syntax: builtin parse translation for "_constify" turns valued
   441 tokens into AST constants;
   442 
   443 * Pure/syntax: prefer later declarations of translations and print
   444 translation functions; potential INCOMPATIBILITY: need to reverse
   445 multiple declarations for same syntax element constant;
   446 
   447 * Pure/show_hyps reset by default (in accordance to existing Isar
   448 practice);
   449 
   450 * Provers/classical: renamed addaltern to addafter, addSaltern to
   451 addSafter;
   452 
   453 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   454 as well;
   455 
   456 * system: tested support for MacOS X; should be able to get Isabelle +
   457 Proof General to work in a plain Terminal after installing Poly/ML
   458 (e.g. from the Isabelle distribution area) and GNU bash alone
   459 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   460 support requires further installations, e.g. from
   461 http://fink.sourceforge.net/);
   462 
   463 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   464 
   465 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   466 of 40 MB), cf. ML_OPTIONS;
   467 
   468 * system: Proof General keywords specification is now part of the
   469 Isabelle distribution (see etc/isar-keywords.el);
   470 
   471 * system: support for persistent Proof General sessions (refrain from
   472 outdating all loaded theories on startup); user may create writable
   473 logic images like this: ``isabelle -q HOL Test'';
   474 
   475 * system: smart selection of Isabelle process versus Isabelle
   476 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   477 run both "isabelle" and "Isabelle" even if file names are badly
   478 damaged (executable inspects the case of the first letter of its own
   479 name); added separate "isabelle-process" and "isabelle-interface";
   480 
   481 * system: refrain from any attempt at filtering input streams; no
   482 longer support ``8bit'' encoding of old isabelle font, instead proper
   483 iso-latin characters may now be used; the related isatools
   484 "symbolinput" and "nonascii" have disappeared as well;
   485 
   486 * system: removed old "xterm" interface (the print modes "xterm" and
   487 "xterm_color" are still available for direct use in a suitable
   488 terminal);
   489 
   490 
   491 
   492 New in Isabelle99-2 (February 2001)
   493 -----------------------------------
   494 
   495 *** Overview of INCOMPATIBILITIES ***
   496 
   497 * HOL: please note that theories in the Library and elsewhere often use the
   498 new-style (Isar) format; to refer to their theorems in an ML script you must
   499 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   500 
   501 * HOL: inductive package no longer splits induction rule aggressively,
   502 but only as far as specified by the introductions given; the old
   503 format may be recovered via ML function complete_split_rule or attribute
   504 'split_rule (complete)';
   505 
   506 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   507 gfp_Tarski to gfp_unfold;
   508 
   509 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   510 
   511 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   512 relation); infix "^^" has been renamed "``"; infix "``" has been
   513 renamed "`"; "univalent" has been renamed "single_valued";
   514 
   515 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   516 operation;
   517 
   518 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   519 
   520 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   521 
   522 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   523 consequence, it is no longer monotonic wrt. the local goal context
   524 (which is now passed through the inductive cases);
   525 
   526 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   527 \<gg> to \<ggreater>;
   528 
   529 
   530 *** Document preparation ***
   531 
   532 * \isabellestyle{NAME} selects version of Isabelle output (currently
   533 available: are "it" for near math-mode best-style output, "sl" for
   534 slanted text style, and "tt" for plain type-writer; if no
   535 \isabellestyle command is given, output is according to slanted
   536 type-writer);
   537 
   538 * support sub/super scripts (for single symbols only), input syntax is
   539 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   540 
   541 * some more standard symbols; see Appendix A of the system manual for
   542 the complete list of symbols defined in isabellesym.sty;
   543 
   544 * improved isabelle style files; more abstract symbol implementation
   545 (should now use \isamath{...} and \isatext{...} in custom symbol
   546 definitions);
   547 
   548 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   549 state; Note that presentation of goal states does not conform to
   550 actual human-readable proof documents.  Please do not include goal
   551 states into document output unless you really know what you are doing!
   552 
   553 * proper indentation of antiquoted output with proportional LaTeX
   554 fonts;
   555 
   556 * no_document ML operator temporarily disables LaTeX document
   557 generation;
   558 
   559 * isatool unsymbolize tunes sources for plain ASCII communication;
   560 
   561 
   562 *** Isar ***
   563 
   564 * Pure: Isar now suffers initial goal statements to contain unbound
   565 schematic variables (this does not conform to actual readable proof
   566 documents, due to unpredictable outcome and non-compositional proof
   567 checking); users who know what they are doing may use schematic goals
   568 for Prolog-style synthesis of proven results;
   569 
   570 * Pure: assumption method (an implicit finishing) now handles actual
   571 rules as well;
   572 
   573 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   574 initial goal, declare "that" only as Pure intro (only for single
   575 steps); the "that" rule assumption may now be involved in implicit
   576 finishing, thus ".." becomes a feasible for trivial obtains;
   577 
   578 * Pure: default proof step now includes 'intro_classes'; thus trivial
   579 instance proofs may be performed by "..";
   580 
   581 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   582 statements as well;
   583 
   584 * Pure: more robust selection of calculational rules;
   585 
   586 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   587 rule (as well as the assumption rule);
   588 
   589 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   590 lemmas, using the graph browser tool;
   591 
   592 * Pure: predict failure of "show" in interactive mode;
   593 
   594 * Pure: 'thms_containing' now takes actual terms as arguments;
   595 
   596 * HOL: improved method 'induct' --- now handles non-atomic goals
   597 (potential INCOMPATIBILITY); tuned error handling;
   598 
   599 * HOL: cases and induct rules now provide explicit hints about the
   600 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   601 any remaining facts are inserted into the goal verbatim;
   602 
   603 * HOL: local contexts (aka cases) may now contain term bindings as
   604 well; the 'cases' and 'induct' methods new provide a ?case binding for
   605 the result to be shown in each case;
   606 
   607 * HOL: added 'recdef_tc' command;
   608 
   609 * isatool convert assists in eliminating legacy ML scripts;
   610 
   611 
   612 *** HOL ***
   613 
   614 * HOL/Library: a collection of generic theories to be used together
   615 with main HOL; the theory loader path already includes this directory
   616 by default; the following existing theories have been moved here:
   617 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   618 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   619 
   620 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   621 modelling and verification task performed in Isabelle/HOL +
   622 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   623 
   624 * HOL/Algebra: special summation operator SUM no longer exists, it has
   625 been replaced by setsum; infix 'assoc' now has priority 50 (like
   626 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   627 'domain', this makes the theory consistent with mathematical
   628 literature;
   629 
   630 * HOL basics: added overloaded operations "inverse" and "divide"
   631 (infix "/"), syntax for generic "abs" operation, generic summation
   632 operator \<Sum>;
   633 
   634 * HOL/typedef: simplified package, provide more useful rules (see also
   635 HOL/subset.thy);
   636 
   637 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   638 now expressed as a proper nested rule (old-style tactic scripts may
   639 require atomize_strip_tac to cope with non-atomic premises);
   640 
   641 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   642 to "split_conv" (old name still available for compatibility);
   643 
   644 * HOL: improved concrete syntax for strings (e.g. allows translation
   645 rules with string literals);
   646 
   647 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   648  and Fleuriot's mechanization of analysis, including the transcendental
   649  functions for the reals;
   650 
   651 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   652 
   653 
   654 *** CTT ***
   655 
   656 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   657 "lam" is displayed as TWO lambda-symbols
   658 
   659 * CTT: theory Main now available, containing everything (that is, Bool
   660 and Arith);
   661 
   662 
   663 *** General ***
   664 
   665 * Pure: the Simplifier has been implemented properly as a derived rule
   666 outside of the actual kernel (at last!); the overall performance
   667 penalty in practical applications is about 50%, while reliability of
   668 the Isabelle inference kernel has been greatly improved;
   669 
   670 * print modes "brackets" and "no_brackets" control output of nested =>
   671 (types) and ==> (props); the default behaviour is "brackets";
   672 
   673 * Provers: fast_tac (and friends) now handle actual object-logic rules
   674 as assumptions as well;
   675 
   676 * system: support Poly/ML 4.0;
   677 
   678 * system: isatool install handles KDE version 1 or 2;
   679 
   680 
   681 
   682 New in Isabelle99-1 (October 2000)
   683 ----------------------------------
   684 
   685 *** Overview of INCOMPATIBILITIES ***
   686 
   687 * HOL: simplification of natural numbers is much changed; to partly
   688 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   689 issue the following ML commands:
   690 
   691   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   692   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   693 
   694 * HOL: simplification no longer dives into case-expressions; this is
   695 controlled by "t.weak_case_cong" for each datatype t;
   696 
   697 * HOL: nat_less_induct renamed to less_induct;
   698 
   699 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   700 fixsome to patch .thy and .ML sources automatically;
   701 
   702   select_equality  -> some_equality
   703   select_eq_Ex     -> some_eq_ex
   704   selectI2EX       -> someI2_ex
   705   selectI2         -> someI2
   706   selectI          -> someI
   707   select1_equality -> some1_equality
   708   Eps_sym_eq       -> some_sym_eq_trivial
   709   Eps_eq           -> some_eq_trivial
   710 
   711 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   712 
   713 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   714 instead);
   715 
   716 * HOL: the recursion equations generated by 'recdef' are now called
   717 f.simps instead of f.rules;
   718 
   719 * HOL: qed_spec_mp now also handles bounded ALL as well;
   720 
   721 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   722 sometimes be needed;
   723 
   724 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   725 
   726 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   727 
   728 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   729 product is now "<*>" instead of "Times"; the lexicographic product is
   730 now "<*lex*>" instead of "**";
   731 
   732 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   733 of main HOL, but was unused); better use HOL's datatype package;
   734 
   735 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   736 the old syntax may be recovered as follows:
   737 
   738   syntax (symbols)
   739     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   740       (infixl "\\<oplus>" 100)
   741 
   742 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   743 
   744 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   745 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   746 internally;
   747 
   748 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   749 changed from A/r to A//r;
   750 
   751 * ZF: new treatment of arithmetic (nat & int) may break some old
   752 proofs;
   753 
   754 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   755 rulify -> rule_format, elimify -> elim_format, ...);
   756 
   757 * Isar/Provers: intro/elim/dest attributes changed; renamed
   758 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   759 should have to change intro!! to intro? only); replaced "delrule" by
   760 "rule del";
   761 
   762 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   763 
   764 * Provers: strengthened force_tac by using new first_best_tac;
   765 
   766 * LaTeX document preparation: several changes of isabelle.sty (see
   767 lib/texinputs);
   768 
   769 
   770 *** Document preparation ***
   771 
   772 * formal comments (text blocks etc.) in new-style theories may now
   773 contain antiquotations of thm/prop/term/typ/text to be presented
   774 according to latex print mode; concrete syntax is like this:
   775 @{term[show_types] "f(x) = a + x"};
   776 
   777 * isatool mkdir provides easy setup of Isabelle session directories,
   778 including proper document sources;
   779 
   780 * generated LaTeX sources are now deleted after successful run
   781 (isatool document -c); may retain a copy somewhere else via -D option
   782 of isatool usedir;
   783 
   784 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   785 style files, achieving self-contained LaTeX sources and simplifying
   786 LaTeX debugging;
   787 
   788 * old-style theories now produce (crude) LaTeX output as well;
   789 
   790 * browser info session directories are now self-contained (may be put
   791 on WWW server seperately); improved graphs of nested sessions; removed
   792 graph for 'all sessions';
   793 
   794 * several improvements in isabelle style files; \isabellestyle{it}
   795 produces fake math mode output; \isamarkupheader is now \section by
   796 default; see lib/texinputs/isabelle.sty etc.;
   797 
   798 
   799 *** Isar ***
   800 
   801 * Isar/Pure: local results and corresponding term bindings are now
   802 subject to Hindley-Milner polymorphism (similar to ML); this
   803 accommodates incremental type-inference very nicely;
   804 
   805 * Isar/Pure: new derived language element 'obtain' supports
   806 generalized existence reasoning;
   807 
   808 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   809 support accumulation of results, without applying any rules yet;
   810 useful to collect intermediate results without explicit name
   811 references, and for use with transitivity rules with more than 2
   812 premises;
   813 
   814 * Isar/Pure: scalable support for case-analysis type proofs: new
   815 'case' language element refers to local contexts symbolically, as
   816 produced by certain proof methods; internally, case names are attached
   817 to theorems as "tags";
   818 
   819 * Isar/Pure: theory command 'hide' removes declarations from
   820 class/type/const name spaces;
   821 
   822 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   823 indicate potential overloading;
   824 
   825 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   826 
   827 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   828 "{a,b,c}" instead of {a,b,c};
   829 
   830 * Isar/Pure now provides its own version of intro/elim/dest
   831 attributes; useful for building new logics, but beware of confusion
   832 with the version in Provers/classical;
   833 
   834 * Isar/Pure: the local context of (non-atomic) goals is provided via
   835 case name 'antecedent';
   836 
   837 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   838 to the current context is now done automatically);
   839 
   840 * Isar/Pure: theory command 'method_setup' provides a simple interface
   841 for definining proof methods in ML;
   842 
   843 * Isar/Provers: intro/elim/dest attributes changed; renamed
   844 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   845 most cases, one should have to change intro!! to intro? only);
   846 replaced "delrule" by "rule del";
   847 
   848 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   849 'symmetric' attribute (the latter supercedes [RS sym]);
   850 
   851 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   852 method modifier); 'simp' method: 'only:' modifier removes loopers as
   853 well (including splits);
   854 
   855 * Isar/Provers: Simplifier and Classical methods now support all kind
   856 of modifiers used in the past, including 'cong', 'iff', etc.
   857 
   858 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   859 of Simplifier and Classical reasoner);
   860 
   861 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   862 now support named cases; major packages (inductive, datatype, primrec,
   863 recdef) support case names and properly name parameters;
   864 
   865 * Isar/HOL: new transitivity rules for substitution in inequalities --
   866 monotonicity conditions are extracted to be proven at end of
   867 calculations;
   868 
   869 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   870 method anyway;
   871 
   872 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   873 split_if split_if_asm; datatype package provides theorems foo.splits =
   874 foo.split foo.split_asm for each datatype;
   875 
   876 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   877 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   878 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   879 use "(cases (simplified))" method in proper proof texts);
   880 
   881 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   882 
   883 * Isar: names of theorems etc. may be natural numbers as well;
   884 
   885 * Isar: 'pr' command: optional arguments for goals_limit and
   886 ProofContext.prems_limit; no longer prints theory contexts, but only
   887 proof states;
   888 
   889 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   890 additional print modes to be specified; e.g. "pr(latex)" will print
   891 proof state according to the Isabelle LaTeX style;
   892 
   893 * Isar: improved support for emulating tactic scripts, including proof
   894 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   895 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   896 (for HOL datatypes);
   897 
   898 * Isar: simplified (more robust) goal selection of proof methods: 1st
   899 goal, all goals, or explicit goal specifier (tactic emulation); thus
   900 'proof method scripts' have to be in depth-first order;
   901 
   902 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   903 
   904 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   905 should instead use individual commands for printing items
   906 (print_commands, print_methods etc.);
   907 
   908 * Isar: added 'nothing' --- the empty list of theorems;
   909 
   910 
   911 *** HOL ***
   912 
   913 * HOL/MicroJava: formalization of a fragment of Java, together with a
   914 corresponding virtual machine and a specification of its bytecode
   915 verifier and a lightweight bytecode verifier, including proofs of
   916 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   917 Cornelia Pusch (see also the homepage of project Bali at
   918 http://isabelle.in.tum.de/Bali/);
   919 
   920 * HOL/Algebra: new theory of rings and univariate polynomials, by
   921 Clemens Ballarin;
   922 
   923 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   924 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   925 Rasmussen;
   926 
   927 * HOL/Lattice: fundamental concepts of lattice theory and order
   928 structures, including duals, properties of bounds versus algebraic
   929 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   930 Theorem for complete lattices etc.; may also serve as a demonstration
   931 for abstract algebraic reasoning using axiomatic type classes, and
   932 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   933 
   934 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   935 von Oheimb;
   936 
   937 * HOL/IMPP: extension of IMP with local variables and mutually
   938 recursive procedures, by David von Oheimb;
   939 
   940 * HOL/Lambda: converted into new-style theory and document;
   941 
   942 * HOL/ex/Multiquote: example of multiple nested quotations and
   943 anti-quotations -- basically a generalized version of de-Bruijn
   944 representation; very useful in avoiding lifting of operations;
   945 
   946 * HOL/record: added general record equality rule to simpset; fixed
   947 select-update simplification procedure to handle extended records as
   948 well; admit "r" as field name;
   949 
   950 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   951 other numeric types and also as the identity of groups, rings, etc.;
   952 
   953 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   954 Types nat and int belong to this axclass;
   955 
   956 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   957    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   958    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   959   two terms #m*u and #n*u are replaced by #(m+n)*u
   960     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   961   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   962     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   963 
   964 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   965 powerful prover for predicate logic but knows nothing of clasets; see
   966 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   967 
   968 * HOL: new version of "case_tac" subsumes both boolean case split and
   969 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   970 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   971 
   972 * HOL: simplification no longer dives into case-expressions: only the
   973 selector expression is simplified, but not the remaining arms; to
   974 enable full simplification of case-expressions for datatype t, you may
   975 remove t.weak_case_cong from the simpset, either globally (Delcongs
   976 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   977 
   978 * HOL/recdef: the recursion equations generated by 'recdef' for
   979 function 'f' are now called f.simps instead of f.rules; if all
   980 termination conditions are proved automatically, these simplification
   981 rules are added to the simpset, as in primrec; rules may be named
   982 individually as well, resulting in a separate list of theorems for
   983 each equation;
   984 
   985 * HOL/While is a new theory that provides a while-combinator. It
   986 permits the definition of tail-recursive functions without the
   987 provision of a termination measure. The latter is necessary once the
   988 invariant proof rule for while is applied.
   989 
   990 * HOL: new (overloaded) notation for the set of elements below/above
   991 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   992 
   993 * HOL: theorems impI, allI, ballI bound as "strip";
   994 
   995 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   996 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   997 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   998 
   999 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1000 
  1001 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1002 main HOL, but was unused);
  1003 
  1004 * HOL: fewer consts declared as global (e.g. have to refer to
  1005 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1006 
  1007 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1008 in case of overlap with user translations (e.g. judgements over
  1009 tuples); (note that the underlying logical represenation is still
  1010 bogus);
  1011 
  1012 
  1013 *** ZF ***
  1014 
  1015 * ZF: simplification automatically cancels common terms in arithmetic
  1016 expressions over nat and int;
  1017 
  1018 * ZF: new treatment of nat to minimize type-checking: all operators
  1019 coerce their operands to a natural number using the function natify,
  1020 making the algebraic laws unconditional;
  1021 
  1022 * ZF: as above, for int: operators coerce their operands to an integer
  1023 using the function intify;
  1024 
  1025 * ZF: the integer library now contains many of the usual laws for the
  1026 orderings, including $<=, and monotonicity laws for $+ and $*;
  1027 
  1028 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1029 simplification;
  1030 
  1031 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1032 to the simplifier and classical reasoner simultaneously;
  1033 
  1034 
  1035 *** General ***
  1036 
  1037 * Provers: blast_tac now handles actual object-logic rules as
  1038 assumptions; note that auto_tac uses blast_tac internally as well;
  1039 
  1040 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1041 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1042 
  1043 * Provers: delrules now handles destruct rules as well (no longer need
  1044 explicit make_elim);
  1045 
  1046 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1047   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1048 use instead the strong form,
  1049   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1050 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1051 from destruct-rules;
  1052 
  1053 * Provers: Simplifier.easy_setup provides a fast path to basic
  1054 Simplifier setup for new object-logics;
  1055 
  1056 * Pure: AST translation rules no longer require constant head on LHS;
  1057 
  1058 * Pure: improved name spaces: ambiguous output is qualified; support
  1059 for hiding of names;
  1060 
  1061 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1062 XSYMBOL_HOME; no longer need to do manual configuration in most
  1063 situations;
  1064 
  1065 * system: compression of ML heaps images may now be controlled via -c
  1066 option of isabelle and isatool usedir (currently only observed by
  1067 Poly/ML);
  1068 
  1069 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1070 useful for remote X11);
  1071 
  1072 * system: provide TAGS file for Isabelle sources;
  1073 
  1074 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1075 order;
  1076 
  1077 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1078 timing flag supersedes proof_timing and Toplevel.trace;
  1079 
  1080 * ML: new combinators |>> and |>>> for incremental transformations
  1081 with secondary results (e.g. certain theory extensions):
  1082 
  1083 * ML: PureThy.add_defs gets additional argument to indicate potential
  1084 overloading (usually false);
  1085 
  1086 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1087 results;
  1088 
  1089 
  1090 
  1091 New in Isabelle99 (October 1999)
  1092 --------------------------------
  1093 
  1094 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1095 
  1096 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1097 are no longer simplified.  (This allows the simplifier to unfold recursive
  1098 functional programs.)  To restore the old behaviour, declare
  1099 
  1100     Delcongs [if_weak_cong];
  1101 
  1102 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1103 complement;
  1104 
  1105 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1106 
  1107 * HOL/datatype: mutual_induct_tac no longer exists --
  1108   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1109 
  1110 * HOL/typedef: fixed type inference for representing set; type
  1111 arguments now have to occur explicitly on the rhs as type constraints;
  1112 
  1113 * ZF: The con_defs part of an inductive definition may no longer refer
  1114 to constants declared in the same theory;
  1115 
  1116 * HOL, ZF: the function mk_cases, generated by the inductive
  1117 definition package, has lost an argument.  To simplify its result, it
  1118 uses the default simpset instead of a supplied list of theorems.
  1119 
  1120 * HOL/List: the constructors of type list are now Nil and Cons;
  1121 
  1122 * Simplifier: the type of the infix ML functions
  1123         setSSolver addSSolver setSolver addSolver
  1124 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1125 for packaging solvers. A solver is created via
  1126         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1127 where the string argument is only a comment.
  1128 
  1129 
  1130 *** Proof tools ***
  1131 
  1132 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1133 decision procedure for linear arithmetic. Currently it is used for
  1134 types `nat', `int', and `real' in HOL (see below); it can, should and
  1135 will be instantiated for other types and logics as well.
  1136 
  1137 * The simplifier now accepts rewrite rules with flexible heads, eg
  1138      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1139   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1140   matching.
  1141 
  1142 
  1143 *** General ***
  1144 
  1145 * New Isabelle/Isar subsystem provides an alternative to traditional
  1146 tactical theorem proving; together with the ProofGeneral/isar user
  1147 interface it offers an interactive environment for developing human
  1148 readable proof documents (Isar == Intelligible semi-automated
  1149 reasoning); for further information see isatool doc isar-ref,
  1150 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1151 
  1152 * improved and simplified presentation of theories: better HTML markup
  1153 (including colors), graph views in several sizes; isatool usedir now
  1154 provides a proper interface for user theories (via -P option); actual
  1155 document preparation based on (PDF)LaTeX is available as well (for
  1156 new-style theories only); see isatool doc system for more information;
  1157 
  1158 * native support for Proof General, both for classic Isabelle and
  1159 Isabelle/Isar;
  1160 
  1161 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1162 using the graph browser tool;
  1163 
  1164 * Isabelle manuals now also available as PDF;
  1165 
  1166 * theory loader rewritten from scratch (may not be fully
  1167 bug-compatible); old loadpath variable has been replaced by show_path,
  1168 add_path, del_path, reset_path functions; new operations such as
  1169 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1170 isatool doc ref);
  1171 
  1172 * improved isatool install: option -k creates KDE application icon,
  1173 option -p DIR installs standalone binaries;
  1174 
  1175 * added ML_PLATFORM setting (useful for cross-platform installations);
  1176 more robust handling of platform specific ML images for SML/NJ;
  1177 
  1178 * the settings environment is now statically scoped, i.e. it is never
  1179 created again in sub-processes invoked from isabelle, isatool, or
  1180 Isabelle;
  1181 
  1182 * path element specification '~~' refers to '$ISABELLE_HOME';
  1183 
  1184 * in locales, the "assumes" and "defines" parts may be omitted if
  1185 empty;
  1186 
  1187 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1188 long arrows);
  1189 
  1190 * new print_mode "HTML";
  1191 
  1192 * new flag show_tags controls display of tags of theorems (which are
  1193 basically just comments that may be attached by some tools);
  1194 
  1195 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1196 mode and goal output format:
  1197 
  1198 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1199 244c244
  1200 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1201 ---
  1202 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1203 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1204 181c181
  1205 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1206 ---
  1207 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1208 
  1209 * function bind_thms stores lists of theorems (cf. bind_thm);
  1210 
  1211 * new shorthand tactics ftac, eatac, datac, fatac;
  1212 
  1213 * qed (and friends) now accept "" as result name; in that case the
  1214 theorem is not stored, but proper checks and presentation of the
  1215 result still apply;
  1216 
  1217 * theorem database now also indexes constants "Trueprop", "all",
  1218 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1219 
  1220 
  1221 *** HOL ***
  1222 
  1223 ** HOL arithmetic **
  1224 
  1225 * There are now decision procedures for linear arithmetic over nat and
  1226 int:
  1227 
  1228 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1229 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1230 are treated as atomic; subformulae not involving type `nat' or `int'
  1231 are ignored; quantified subformulae are ignored unless they are
  1232 positive universal or negative existential. The tactic has to be
  1233 invoked by hand and can be a little bit slow. In particular, the
  1234 running time is exponential in the number of occurrences of `min' and
  1235 `max', and `-' on `nat'.
  1236 
  1237 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1238 (negated) (in)equalities among the premises and the conclusion into
  1239 account (i.e. no compound formulae) and does not know about `min' and
  1240 `max', and `-' on `nat'. It is fast and is used automatically by the
  1241 simplifier.
  1242 
  1243 NB: At the moment, these decision procedures do not cope with mixed
  1244 nat/int formulae where the two parts interact, such as `m < n ==>
  1245 int(m) < int(n)'.
  1246 
  1247 * HOL/Numeral provides a generic theory of numerals (encoded
  1248 efficiently as bit strings); setup for types nat/int/real is in place;
  1249 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1250 int, existing theories and proof scripts may require a few additional
  1251 type constraints;
  1252 
  1253 * integer division and remainder can now be performed on constant
  1254 arguments;
  1255 
  1256 * many properties of integer multiplication, division and remainder
  1257 are now available;
  1258 
  1259 * An interface to the Stanford Validity Checker (SVC) is available through the
  1260 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1261 are proved automatically.  SVC must be installed separately, and its results
  1262 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1263 invocation of the underlying oracle).  For SVC see
  1264   http://verify.stanford.edu/SVC
  1265 
  1266 * IsaMakefile: the HOL-Real target now builds an actual image;
  1267 
  1268 
  1269 ** HOL misc **
  1270 
  1271 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1272 (in Isabelle/Isar) -- by Gertrud Bauer;
  1273 
  1274 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1275 analysis for assembly languages with subtypes;
  1276 
  1277 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1278 -- avoids syntactic ambiguities and treats state, transition, and
  1279 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1280 changed syntax and (many) tactics;
  1281 
  1282 * HOL/inductive: Now also handles more general introduction rules such
  1283   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1284   theorems are now maintained within the theory (maintained via the
  1285   "mono" attribute);
  1286 
  1287 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1288   (using function types) such as
  1289 
  1290   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1291 
  1292 * HOL/record: record_simproc (part of the default simpset) takes care
  1293 of selectors applied to updated records; record_split_tac is no longer
  1294 part of the default claset; update_defs may now be removed from the
  1295 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1296 
  1297   claset_ref () := claset() addSWrapper record_split_wrapper;
  1298   Delsimprocs [record_simproc]
  1299 
  1300 * HOL/typedef: fixed type inference for representing set; type
  1301 arguments now have to occur explicitly on the rhs as type constraints;
  1302 
  1303 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1304 names rather than an ML expression;
  1305 
  1306 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1307 supplied later.  Program schemes can be defined, such as
  1308     "While B C s = (if B s then While B C (C s) else s)"
  1309 where the well-founded relation can be chosen after B and C have been given.
  1310 
  1311 * HOL/List: the constructors of type list are now Nil and Cons;
  1312 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1313 course, ML tools referring to List.list.op # etc. have to be adapted;
  1314 
  1315 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1316 disabled by default; run isabelle with option -m HOL to get back to
  1317 the original Gordon/HOL-style output;
  1318 
  1319 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1320 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1321 
  1322 * HOL basic syntax simplified (more orthogonal): all variants of
  1323 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1324 Eps operator is provided as well: "SOME x. P[x]";
  1325 
  1326 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1327 
  1328 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1329 thus available for user theories;
  1330 
  1331 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1332 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1333 time;
  1334 
  1335 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1336 several times and then mp;
  1337 
  1338 
  1339 *** LK ***
  1340 
  1341 * the notation <<...>> is now available as a notation for sequences of
  1342 formulas;
  1343 
  1344 * the simplifier is now installed
  1345 
  1346 * the axiom system has been generalized (thanks to Soren Heilmann)
  1347 
  1348 * the classical reasoner now has a default rule database
  1349 
  1350 
  1351 *** ZF ***
  1352 
  1353 * new primrec section allows primitive recursive functions to be given
  1354 directly (as in HOL) over datatypes and the natural numbers;
  1355 
  1356 * new tactics induct_tac and exhaust_tac for induction (or case
  1357 analysis) over datatypes and the natural numbers;
  1358 
  1359 * the datatype declaration of type T now defines the recursor T_rec;
  1360 
  1361 * simplification automatically does freeness reasoning for datatype
  1362 constructors;
  1363 
  1364 * automatic type-inference, with AddTCs command to insert new
  1365 type-checking rules;
  1366 
  1367 * datatype introduction rules are now added as Safe Introduction rules
  1368 to the claset;
  1369 
  1370 * the syntax "if P then x else y" is now available in addition to
  1371 if(P,x,y);
  1372 
  1373 
  1374 *** Internal programming interfaces ***
  1375 
  1376 * tuned simplifier trace output; new flag debug_simp;
  1377 
  1378 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1379 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1380 
  1381 * AxClass.axclass_tac lost the theory argument;
  1382 
  1383 * tuned current_goals_markers semantics: begin / end goal avoids
  1384 printing empty lines;
  1385 
  1386 * removed prs and prs_fn hook, which was broken because it did not
  1387 include \n in its semantics, forcing writeln to add one
  1388 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1389 string -> unit if you really want to output text without newline;
  1390 
  1391 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1392 plain output, interface builders may have to enable 'isabelle_font'
  1393 mode to get Isabelle font glyphs as before;
  1394 
  1395 * refined token_translation interface; INCOMPATIBILITY: output length
  1396 now of type real instead of int;
  1397 
  1398 * theory loader actions may be traced via new ThyInfo.add_hook
  1399 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1400 your own database of information attached to *whole* theories -- as
  1401 opposed to intra-theory data slots offered via TheoryDataFun;
  1402 
  1403 * proper handling of dangling sort hypotheses (at last!);
  1404 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1405 extra sort hypotheses that can be witnessed from the type signature;
  1406 the force_strip_shyps flag is gone, any remaining shyps are simply
  1407 left in the theorem (with a warning issued by strip_shyps_warning);
  1408 
  1409 
  1410 
  1411 New in Isabelle98-1 (October 1998)
  1412 ----------------------------------
  1413 
  1414 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1415 
  1416 * several changes of automated proof tools;
  1417 
  1418 * HOL: major changes to the inductive and datatype packages, including
  1419 some minor incompatibilities of theory syntax;
  1420 
  1421 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1422 called `inj_on';
  1423 
  1424 * HOL: removed duplicate thms in Arith:
  1425   less_imp_add_less  should be replaced by  trans_less_add1
  1426   le_imp_add_le      should be replaced by  trans_le_add1
  1427 
  1428 * HOL: unary minus is now overloaded (new type constraints may be
  1429 required);
  1430 
  1431 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1432 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1433 now taken as an integer constant.
  1434 
  1435 * Pure: ML function 'theory_of' renamed to 'theory';
  1436 
  1437 
  1438 *** Proof tools ***
  1439 
  1440 * Simplifier:
  1441   1. Asm_full_simp_tac is now more aggressive.
  1442      1. It will sometimes reorient premises if that increases their power to
  1443         simplify.
  1444      2. It does no longer proceed strictly from left to right but may also
  1445         rotate premises to achieve further simplification.
  1446      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1447      old Asm_full_simp_tac in that it does not rotate premises.
  1448   2. The simplifier now knows a little bit about nat-arithmetic.
  1449 
  1450 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1451 allows for selected deletion of wrappers, by introduction of names for
  1452 wrapper functionals.  This implies that addbefore, addSbefore,
  1453 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1454 and that adding two tactics with the same name overwrites the first
  1455 one (emitting a warning).
  1456   type wrapper = (int -> tactic) -> (int -> tactic)
  1457   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1458   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1459   delWrapper, delSWrapper: claset *  string            -> claset
  1460   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1461 
  1462 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1463 semantics; addbefore now affects only the unsafe part of step_tac
  1464 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1465 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1466 by Force_tac;
  1467 
  1468 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1469 compWrapper; added safe wrapper (and access functions for it);
  1470 
  1471 * HOL/split_all_tac is now much faster and fails if there is nothing
  1472 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1473 and the names of the automatically generated variables have changed.
  1474 split_all_tac has moved within claset() from unsafe wrappers to safe
  1475 wrappers, which means that !!-bound variables are split much more
  1476 aggressively, and safe_tac and clarify_tac now split such variables.
  1477 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1478 Note: the same holds for record_split_tac, which does the job of
  1479 split_all_tac for record fields.
  1480 
  1481 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1482 permanently to the default simpset using Addsplits just like
  1483 Addsimps. They can be removed via Delsplits just like
  1484 Delsimps. Lower-case versions are also available.
  1485 
  1486 * HOL/Simplifier: The rule split_if is now part of the default
  1487 simpset. This means that the simplifier will eliminate all occurrences
  1488 of if-then-else in the conclusion of a goal. To prevent this, you can
  1489 either remove split_if completely from the default simpset by
  1490 `Delsplits [split_if]' or remove it in a specific call of the
  1491 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1492 other case splitting rules to/from the default simpset: every datatype
  1493 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1494 t is the name of the datatype).
  1495 
  1496 * Classical reasoner / Simplifier combination: new force_tac (and
  1497 derivatives Force_tac, force) combines rewriting and classical
  1498 reasoning (and whatever other tools) similarly to auto_tac, but is
  1499 aimed to solve the given subgoal completely.
  1500 
  1501 
  1502 *** General ***
  1503 
  1504 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1505 and `goalw': the theory is no longer needed as an explicit argument -
  1506 the current theory context is used; assumptions are no longer returned
  1507 at the ML-level unless one of them starts with ==> or !!; it is
  1508 recommended to convert to these new commands using isatool fixgoal
  1509 (backup your sources first!);
  1510 
  1511 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1512 the current theory context, and 'theory' to lookup stored theories;
  1513 
  1514 * new theory section 'locale' for declaring constants, assumptions and
  1515 definitions that have local scope;
  1516 
  1517 * new theory section 'nonterminals' for purely syntactic types;
  1518 
  1519 * new theory section 'setup' for generic ML setup functions
  1520 (e.g. package initialization);
  1521 
  1522 * the distribution now includes Isabelle icons: see
  1523 lib/logo/isabelle-{small,tiny}.xpm;
  1524 
  1525 * isatool install - install binaries with absolute references to
  1526 ISABELLE_HOME/bin;
  1527 
  1528 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1529 
  1530 * print mode 'emacs' reserved for Isamode;
  1531 
  1532 * support multiple print (ast) translations per constant name;
  1533 
  1534 * theorems involving oracles are now printed with a suffixed [!];
  1535 
  1536 
  1537 *** HOL ***
  1538 
  1539 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1540 
  1541 * HOL/inductive package reorganized and improved: now supports mutual
  1542 definitions such as
  1543 
  1544   inductive EVEN ODD
  1545     intrs
  1546       null "0 : EVEN"
  1547       oddI "n : EVEN ==> Suc n : ODD"
  1548       evenI "n : ODD ==> Suc n : EVEN"
  1549 
  1550 new theorem list "elims" contains an elimination rule for each of the
  1551 recursive sets; inductive definitions now handle disjunctive premises
  1552 correctly (also ZF);
  1553 
  1554 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1555 "mutual_induct" no longer exists - the induction rule is always
  1556 contained in "induct";
  1557 
  1558 
  1559 * HOL/datatype package re-implemented and greatly improved: now
  1560 supports mutually recursive datatypes such as
  1561 
  1562   datatype
  1563     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1564             | SUM ('a aexp) ('a aexp)
  1565             | DIFF ('a aexp) ('a aexp)
  1566             | NUM 'a
  1567   and
  1568     'a bexp = LESS ('a aexp) ('a aexp)
  1569             | AND ('a bexp) ('a bexp)
  1570             | OR ('a bexp) ('a bexp)
  1571 
  1572 as well as indirectly recursive datatypes such as
  1573 
  1574   datatype
  1575     ('a, 'b) term = Var 'a
  1576                   | App 'b ((('a, 'b) term) list)
  1577 
  1578 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1579 induction on mutually / indirectly recursive datatypes.
  1580 
  1581 Primrec equations are now stored in theory and can be accessed via
  1582 <function_name>.simps.
  1583 
  1584 INCOMPATIBILITIES:
  1585 
  1586   - Theories using datatypes must now have theory Datatype as an
  1587     ancestor.
  1588   - The specific <typename>.induct_tac no longer exists - use the
  1589     generic induct_tac instead.
  1590   - natE has been renamed to nat.exhaust - use exhaust_tac
  1591     instead of res_inst_tac ... natE. Note that the variable
  1592     names in nat.exhaust differ from the names in natE, this
  1593     may cause some "fragile" proofs to fail.
  1594   - The theorems split_<typename>_case and split_<typename>_case_asm
  1595     have been renamed to <typename>.split and <typename>.split_asm.
  1596   - Since default sorts of type variables are now handled correctly,
  1597     some datatype definitions may have to be annotated with explicit
  1598     sort constraints.
  1599   - Primrec definitions no longer require function name and type
  1600     of recursive argument.
  1601 
  1602 Consider using isatool fixdatatype to adapt your theories and proof
  1603 scripts to the new package (backup your sources first!).
  1604 
  1605 
  1606 * HOL/record package: considerably improved implementation; now
  1607 includes concrete syntax for record types, terms, updates; theorems
  1608 for surjective pairing and splitting !!-bound record variables; proof
  1609 support is as follows:
  1610 
  1611   1) standard conversions (selectors or updates applied to record
  1612 constructor terms) are part of the standard simpset;
  1613 
  1614   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1615 made part of standard simpset and claset via addIffs;
  1616 
  1617   3) a tactic for record field splitting (record_split_tac) is part of
  1618 the standard claset (addSWrapper);
  1619 
  1620 To get a better idea about these rules you may retrieve them via
  1621 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1622 the name of your record type.
  1623 
  1624 The split tactic 3) conceptually simplifies by the following rule:
  1625 
  1626   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1627 
  1628 Thus any record variable that is bound by meta-all will automatically
  1629 blow up into some record constructor term, consequently the
  1630 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1631 solve record problems automatically.
  1632 
  1633 
  1634 * reorganized the main HOL image: HOL/Integ and String loaded by
  1635 default; theory Main includes everything;
  1636 
  1637 * automatic simplification of integer sums and comparisons, using cancellation;
  1638 
  1639 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1640 
  1641 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1642 
  1643 * many new identities for unions, intersections, set difference, etc.;
  1644 
  1645 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1646 called split_if, split_split, split_sum_case and split_nat_case (to go
  1647 with add/delsplits);
  1648 
  1649 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1650 (?x::unit) = (); this is made part of the default simpset, which COULD
  1651 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1652 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1653 unit_abs_eta_conv is added in order to counter the effect of
  1654 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1655 %u.f();
  1656 
  1657 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1658 makes more sense);
  1659 
  1660 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1661   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1662   disjointness reasoning but breaking a few old proofs.
  1663 
  1664 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1665 to 'converse' from 'inverse' (for compatibility with ZF and some
  1666 literature);
  1667 
  1668 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1669 the well-founded relation;
  1670 
  1671 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1672     Compl A.  The "Compl" syntax remains available as input syntax for this
  1673     release ONLY.
  1674 
  1675 * HOL/Update: new theory of function updates:
  1676     f(a:=b) == %x. if x=a then b else f x
  1677 may also be iterated as in f(a:=b,c:=d,...);
  1678 
  1679 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1680 
  1681 * HOL/List:
  1682   - new function list_update written xs[i:=v] that updates the i-th
  1683     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1684   - new function `upt' written [i..j(] which generates the list
  1685     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1686     bound write [i..j], which is a shorthand for [i..j+1(].
  1687   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1688 
  1689 * HOL/Arith:
  1690   - removed 'pred' (predecessor) function;
  1691   - generalized some theorems about n-1;
  1692   - many new laws about "div" and "mod";
  1693   - new laws about greatest common divisors (see theory ex/Primes);
  1694 
  1695 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1696 instead of "inverse";
  1697 
  1698 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1699   of the multiset ordering;
  1700 
  1701 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1702   (not included by default);
  1703 
  1704 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1705 
  1706 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1707   programs, i.e. different program variables may have different types.
  1708 
  1709 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1710   [previously, this check worked only if the rewrite rule was unconditional]
  1711   Now rew can involve either definitions or equalities (either == or =).
  1712 
  1713 
  1714 *** ZF ***
  1715 
  1716 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1717   only the theorems proved on ZF.ML;
  1718 
  1719 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1720   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1721   disjointness reasoning but breaking a few old proofs.
  1722 
  1723 * ZF/Update: new theory of function updates
  1724     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1725   may also be iterated as in f(a:=b,c:=d,...);
  1726 
  1727 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1728 
  1729 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1730   [previously, this check worked only if the rewrite rule was unconditional]
  1731   Now rew can involve either definitions or equalities (either == or =).
  1732 
  1733 * case_tac provided for compatibility with HOL
  1734     (like the old excluded_middle_tac, but with subgoals swapped)
  1735 
  1736 
  1737 *** Internal programming interfaces ***
  1738 
  1739 * Pure: several new basic modules made available for general use, see
  1740 also src/Pure/README;
  1741 
  1742 * improved the theory data mechanism to support encapsulation (data
  1743 kind name replaced by private Object.kind, acting as authorization
  1744 key); new type-safe user interface via functor TheoryDataFun; generic
  1745 print_data function becomes basically useless;
  1746 
  1747 * removed global_names compatibility flag -- all theory declarations
  1748 are qualified by default;
  1749 
  1750 * module Pure/Syntax now offers quote / antiquote translation
  1751 functions (useful for Hoare logic etc. with implicit dependencies);
  1752 see HOL/ex/Antiquote for an example use;
  1753 
  1754 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1755 cterm -> thm;
  1756 
  1757 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1758 subgoal;
  1759 
  1760 * Display.print_goals function moved to Locale.print_goals;
  1761 
  1762 * standard print function for goals supports current_goals_markers
  1763 variable for marking begin of proof, end of proof, start of goal; the
  1764 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1765 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1766 for example;
  1767 
  1768 
  1769 
  1770 New in Isabelle98 (January 1998)
  1771 --------------------------------
  1772 
  1773 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1774 
  1775 * changed lexical syntax of terms / types: dots made part of long
  1776 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1777 
  1778 * simpset (and claset) reference variable replaced by functions
  1779 simpset / simpset_ref;
  1780 
  1781 * no longer supports theory aliases (via merge) and non-trivial
  1782 implicit merge of thms' signatures;
  1783 
  1784 * most internal names of constants changed due to qualified names;
  1785 
  1786 * changed Pure/Sequence interface (see Pure/seq.ML);
  1787 
  1788 
  1789 *** General Changes ***
  1790 
  1791 * hierachically structured name spaces (for consts, types, axms, thms
  1792 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1793 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1794 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1795 long_names for fully qualified output names; NOTE: ML programs
  1796 (special tactics, packages etc.) referring to internal names may have
  1797 to be adapted to cope with fully qualified names; in case of severe
  1798 backward campatibility problems try setting 'global_names' at compile
  1799 time to have enrything declared within a flat name space; one may also
  1800 fine tune name declarations in theories via the 'global' and 'local'
  1801 section;
  1802 
  1803 * reimplemented the implicit simpset and claset using the new anytype
  1804 data filed in signatures; references simpset:simpset ref etc. are
  1805 replaced by functions simpset:unit->simpset and
  1806 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1807 to patch your ML files accordingly;
  1808 
  1809 * HTML output now includes theory graph data for display with Java
  1810 applet or isatool browser; data generated automatically via isatool
  1811 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1812 
  1813 * defs may now be conditional; improved rewrite_goals_tac to handle
  1814 conditional equations;
  1815 
  1816 * defs now admits additional type arguments, using TYPE('a) syntax;
  1817 
  1818 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1819 creates a new theory node; implicit merge of thms' signatures is
  1820 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1821 transfer:theory->thm->thm in (rare) cases;
  1822 
  1823 * improved handling of draft signatures / theories; draft thms (and
  1824 ctyps, cterms) are automatically promoted to real ones;
  1825 
  1826 * slightly changed interfaces for oracles: admit many per theory, named
  1827 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1828 
  1829 * print_goals: optional output of const types (set show_consts and
  1830 show_types);
  1831 
  1832 * improved output of warnings (###) and errors (***);
  1833 
  1834 * subgoal_tac displays a warning if the new subgoal has type variables;
  1835 
  1836 * removed old README and Makefiles;
  1837 
  1838 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1839 
  1840 * removed obsolete init_pps and init_database;
  1841 
  1842 * deleted the obsolete tactical STATE, which was declared by
  1843     fun STATE tacfun st = tacfun st st;
  1844 
  1845 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1846 (which abbreviates $HOME);
  1847 
  1848 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1849 use isatool fixseq to adapt your ML programs (this works for fully
  1850 qualified references to the Sequence structure only!);
  1851 
  1852 * use_thy no longer requires writable current directory; it always
  1853 reloads .ML *and* .thy file, if either one is out of date;
  1854 
  1855 
  1856 *** Classical Reasoner ***
  1857 
  1858 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1859 tactics that use classical reasoning to simplify a subgoal without
  1860 splitting it into several subgoals;
  1861 
  1862 * Safe_tac: like safe_tac but uses the default claset;
  1863 
  1864 
  1865 *** Simplifier ***
  1866 
  1867 * added simplification meta rules:
  1868     (asm_)(full_)simplify: simpset -> thm -> thm;
  1869 
  1870 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1871 logics (again);
  1872 
  1873 * added prems argument to simplification procedures;
  1874 
  1875 * HOL, FOL, ZF: added infix function `addsplits':
  1876   instead of `<simpset> setloop (split_tac <thms>)'
  1877   you can simply write `<simpset> addsplits <thms>'
  1878 
  1879 
  1880 *** Syntax ***
  1881 
  1882 * TYPE('a) syntax for type reflection terms;
  1883 
  1884 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1885 
  1886 * pretty printer: changed order of mixfix annotation preference (again!);
  1887 
  1888 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1889 
  1890 
  1891 *** HOL ***
  1892 
  1893 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1894   with `addloop' of the simplifier to faciliate case splitting in premises.
  1895 
  1896 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1897 
  1898 * HOL/Auth: new protocol proofs including some for the Internet
  1899   protocol TLS;
  1900 
  1901 * HOL/Map: new theory of `maps' a la VDM;
  1902 
  1903 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1904 cancelling out common nat summands from =, <, <= (in)equalities, or
  1905 differences; simplification procedures nat_cancel_factor for
  1906 cancelling common factor from =, <, <= (in)equalities over natural
  1907 sums; nat_cancel contains both kinds of procedures, it is installed by
  1908 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1909 
  1910 * HOL/simplifier: terms of the form
  1911   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1912   are rewritten to
  1913   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1914   and those of the form
  1915   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1916   are rewritten to
  1917   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1918 
  1919 * HOL/datatype
  1920   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1921 
  1922   P(t_case f1 ... fn x) =
  1923      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1924         ...
  1925        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1926      )
  1927 
  1928   and a theorem `split_t_case_asm' of the form
  1929 
  1930   P(t_case f1 ... fn x) =
  1931     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1932         ...
  1933        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1934      )
  1935   which can be added to a simpset via `addsplits'. The existing theorems
  1936   expand_list_case and expand_option_case have been renamed to
  1937   split_list_case and split_option_case.
  1938 
  1939 * HOL/Arithmetic:
  1940   - `pred n' is automatically converted to `n-1'.
  1941     Users are strongly encouraged not to use `pred' any longer,
  1942     because it will disappear altogether at some point.
  1943   - Users are strongly encouraged to write "0 < n" rather than
  1944     "n ~= 0". Theorems and proof tools have been modified towards this
  1945     `standard'.
  1946 
  1947 * HOL/Lists:
  1948   the function "set_of_list" has been renamed "set" (and its theorems too);
  1949   the function "nth" now takes its arguments in the reverse order and
  1950   has acquired the infix notation "!" as in "xs!n".
  1951 
  1952 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1953 
  1954 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1955   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1956 
  1957 * HOL/record: extensible records with schematic structural subtyping
  1958 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1959 still lacks various theorems and concrete record syntax;
  1960 
  1961 
  1962 *** HOLCF ***
  1963 
  1964 * removed "axioms" and "generated by" sections;
  1965 
  1966 * replaced "ops" section by extended "consts" section, which is capable of
  1967   handling the continuous function space "->" directly;
  1968 
  1969 * domain package:
  1970   . proves theorems immediately and stores them in the theory,
  1971   . creates hierachical name space,
  1972   . now uses normal mixfix annotations (instead of cinfix...),
  1973   . minor changes to some names and values (for consistency),
  1974   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1975   . separator between mutual domain defs: changed "," to "and",
  1976   . improved handling of sort constraints;  now they have to
  1977     appear on the left-hand side of the equations only;
  1978 
  1979 * fixed LAM <x,y,zs>.b syntax;
  1980 
  1981 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1982 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1983 
  1984 
  1985 *** FOL and ZF ***
  1986 
  1987 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1988   with `addloop' of the simplifier to faciliate case splitting in premises.
  1989 
  1990 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1991 in HOL, they strip ALL and --> from proved theorems;
  1992 
  1993 
  1994 
  1995 New in Isabelle94-8 (May 1997)
  1996 ------------------------------
  1997 
  1998 *** General Changes ***
  1999 
  2000 * new utilities to build / run / maintain Isabelle etc. (in parts
  2001 still somewhat experimental); old Makefiles etc. still functional;
  2002 
  2003 * new 'Isabelle System Manual';
  2004 
  2005 * INSTALL text, together with ./configure and ./build scripts;
  2006 
  2007 * reimplemented type inference for greater efficiency, better error
  2008 messages and clean internal interface;
  2009 
  2010 * prlim command for dealing with lots of subgoals (an easier way of
  2011 setting goals_limit);
  2012 
  2013 
  2014 *** Syntax ***
  2015 
  2016 * supports alternative (named) syntax tables (parser and pretty
  2017 printer); internal interface is provided by add_modesyntax(_i);
  2018 
  2019 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2020 be used in conjunction with the Isabelle symbol font; uses the
  2021 "symbols" syntax table;
  2022 
  2023 * added token_translation interface (may translate name tokens in
  2024 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2025 the current print_mode); IMPORTANT: user print translation functions
  2026 are responsible for marking newly introduced bounds
  2027 (Syntax.mark_boundT);
  2028 
  2029 * token translations for modes "xterm" and "xterm_color" that display
  2030 names in bold, underline etc. or colors (which requires a color
  2031 version of xterm);
  2032 
  2033 * infixes may now be declared with names independent of their syntax;
  2034 
  2035 * added typed_print_translation (like print_translation, but may
  2036 access type of constant);
  2037 
  2038 
  2039 *** Classical Reasoner ***
  2040 
  2041 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2042 some limitations.  Blast_tac...
  2043   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2044   + ignores elimination rules that don't have the correct format
  2045         (the conclusion MUST be a formula variable)
  2046   + ignores types, which can make HOL proofs fail
  2047   + rules must not require higher-order unification, e.g. apply_type in ZF
  2048     [message "Function Var's argument not a bound variable" relates to this]
  2049   + its proof strategy is more general but can actually be slower
  2050 
  2051 * substitution with equality assumptions no longer permutes other
  2052 assumptions;
  2053 
  2054 * minor changes in semantics of addafter (now called addaltern); renamed
  2055 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2056 (and access functions for it);
  2057 
  2058 * improved combination of classical reasoner and simplifier:
  2059   + functions for handling clasimpsets
  2060   + improvement of addss: now the simplifier is called _after_ the
  2061     safe steps.
  2062   + safe variant of addss called addSss: uses safe simplifications
  2063     _during_ the safe steps. It is more complete as it allows multiple
  2064     instantiations of unknowns (e.g. with slow_tac).
  2065 
  2066 *** Simplifier ***
  2067 
  2068 * added interface for simplification procedures (functions that
  2069 produce *proven* rewrite rules on the fly, depending on current
  2070 redex);
  2071 
  2072 * ordering on terms as parameter (used for ordered rewriting);
  2073 
  2074 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2075 
  2076 * the solver is now split into a safe and an unsafe part.
  2077 This should be invisible for the normal user, except that the
  2078 functions setsolver and addsolver have been renamed to setSolver and
  2079 addSolver; added safe_asm_full_simp_tac;
  2080 
  2081 
  2082 *** HOL ***
  2083 
  2084 * a generic induction tactic `induct_tac' which works for all datatypes and
  2085 also for type `nat';
  2086 
  2087 * a generic case distinction tactic `exhaust_tac' which works for all
  2088 datatypes and also for type `nat';
  2089 
  2090 * each datatype comes with a function `size';
  2091 
  2092 * patterns in case expressions allow tuple patterns as arguments to
  2093 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2094 
  2095 * primrec now also works with type nat;
  2096 
  2097 * recdef: a new declaration form, allows general recursive functions to be
  2098 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2099 
  2100 * the constant for negation has been renamed from "not" to "Not" to
  2101 harmonize with FOL, ZF, LK, etc.;
  2102 
  2103 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2104 infinite lists;
  2105 
  2106 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2107 
  2108 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2109 problems in commutative rings, using axiomatic type classes for + and *;
  2110 
  2111 * more examples in HOL/MiniML and HOL/Auth;
  2112 
  2113 * more default rewrite rules for quantifiers, union/intersection;
  2114 
  2115 * a new constant `arbitrary == @x.False';
  2116 
  2117 * HOLCF/IOA replaces old HOL/IOA;
  2118 
  2119 * HOLCF changes: derived all rules and arities
  2120   + axiomatic type classes instead of classes
  2121   + typedef instead of faking type definitions
  2122   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2123   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2124   + eliminated the types void, one, tr
  2125   + use unit lift and bool lift (with translations) instead of one and tr
  2126   + eliminated blift from Lift3.thy (use Def instead of blift)
  2127   all eliminated rules are derived as theorems --> no visible changes ;
  2128 
  2129 
  2130 *** ZF ***
  2131 
  2132 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2133 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2134 as ZF_cs addSIs [equalityI];
  2135 
  2136 
  2137 
  2138 New in Isabelle94-7 (November 96)
  2139 ---------------------------------
  2140 
  2141 * allowing negative levels (as offsets) in prlev and choplev;
  2142 
  2143 * super-linear speedup for large simplifications;
  2144 
  2145 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2146 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2147 FAIL); can suppress it using the command Delsimps (ex_simps @
  2148 all_simps); De Morgan laws are also now included, by default;
  2149 
  2150 * improved printing of ==>  :  ~:
  2151 
  2152 * new object-logic "Sequents" adds linear logic, while replacing LK
  2153 and Modal (thanks to Sara Kalvala);
  2154 
  2155 * HOL/Auth: correctness proofs for authentication protocols;
  2156 
  2157 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2158 examples on HOL/Auth);
  2159 
  2160 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2161 the rewriter and classical reasoner simultaneously;
  2162 
  2163 * function uresult no longer returns theorems in "standard" format;
  2164 regain previous version by: val uresult = standard o uresult;
  2165 
  2166 
  2167 
  2168 New in Isabelle94-6
  2169 -------------------
  2170 
  2171 * oracles -- these establish an interface between Isabelle and trusted
  2172 external reasoners, which may deliver results as theorems;
  2173 
  2174 * proof objects (in particular record all uses of oracles);
  2175 
  2176 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2177 
  2178 * "constdefs" section in theory files;
  2179 
  2180 * "primrec" section (HOL) no longer requires names;
  2181 
  2182 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2183 
  2184 
  2185 
  2186 New in Isabelle94-5
  2187 -------------------
  2188 
  2189 * reduced space requirements;
  2190 
  2191 * automatic HTML generation from theories;
  2192 
  2193 * theory files no longer require "..." (quotes) around most types;
  2194 
  2195 * new examples, including two proofs of the Church-Rosser theorem;
  2196 
  2197 * non-curried (1994) version of HOL is no longer distributed;
  2198 
  2199 
  2200 
  2201 New in Isabelle94-4
  2202 -------------------
  2203 
  2204 * greatly reduced space requirements;
  2205 
  2206 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2207 
  2208 * searchable theorem database (see the section "Retrieving theorems" on
  2209 page 8 of the Reference Manual);
  2210 
  2211 * new examples, including Grabczewski's monumental case study of the
  2212 Axiom of Choice;
  2213 
  2214 * The previous version of HOL renamed to Old_HOL;
  2215 
  2216 * The new version of HOL (previously called CHOL) uses a curried syntax
  2217 for functions.  Application looks like f a b instead of f(a,b);
  2218 
  2219 * Mutually recursive inductive definitions finally work in HOL;
  2220 
  2221 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2222 translates to the operator "split";
  2223 
  2224 
  2225 
  2226 New in Isabelle94-3
  2227 -------------------
  2228 
  2229 * new infix operator, addss, allowing the classical reasoner to
  2230 perform simplification at each step of its search.  Example:
  2231         fast_tac (cs addss ss)
  2232 
  2233 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2234 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2235 look like (a,b) instead of <a,b>;
  2236 
  2237 * PLEASE NOTE: CHOL will eventually replace HOL!
  2238 
  2239 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2240 It translates to the operator "split".  A new theory of integers is available;
  2241 
  2242 * In ZF, integer numerals now denote two's-complement binary integers.
  2243 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2244 
  2245 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2246 of the Axiom of Choice;
  2247 
  2248 
  2249 
  2250 New in Isabelle94-2
  2251 -------------------
  2252 
  2253 * Significantly faster resolution;
  2254 
  2255 * the different sections in a .thy file can now be mixed and repeated
  2256 freely;
  2257 
  2258 * Database of theorems for FOL, HOL and ZF.  New
  2259 commands including qed, qed_goal and bind_thm store theorems in the database.
  2260 
  2261 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2262 a given theory (thms_of), or find out what theory a theorem was proved in
  2263 (theory_of_thm);
  2264 
  2265 * Bugs fixed in the inductive definition and datatype packages;
  2266 
  2267 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2268 and HOL_dup_cs obsolete;
  2269 
  2270 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2271 have been removed;
  2272 
  2273 * Simpler definition of function space in ZF;
  2274 
  2275 * new results about cardinal and ordinal arithmetic in ZF;
  2276 
  2277 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2278 types;
  2279 
  2280 
  2281 $Id$