NEWS
author wenzelm
Tue Aug 27 17:24:41 2002 +0200 (2002-08-27)
changeset 13541 44efea0e21fa
parent 13540 aede0306e214
child 13549 f1522b892a4c
permissions -rw-r--r--
*** empty log message ***
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in this Isabelle release
     6 ----------------------------
     7 
     8 *** General ***
     9 
    10 * Pure: locale specifications now produce predicate definitions
    11 according to the body of text (covering assumptions modulo local
    12 definitions); predicate "loc_axioms" covers newly introduced text,
    13 while "loc" is cumulative wrt. all included locale expressions; the
    14 latter view is presented only on export into the global theory
    15 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    16 on the old view without predicates;
    17 
    18 * Pure: predefined locales "var" and "struct" are useful for sharing
    19 parameters (as in CASL, for example); just specify something like
    20 ``var x + var y + struct M'' as import;
    21 
    22 * Pure: improved thms_containing: proper indexing of facts instead of
    23 raw theorems; check validity of results wrt. current name space;
    24 include local facts of proof configuration (also covers active
    25 locales), cover fixed variables in index; may use "_" in term
    26 specification; an optional limit for the number of printed facts may
    27 be given (the default is 40);
    28 
    29 * Pure: disallow duplicate fact bindings within new-style theory files
    30 (batch-mode only);
    31 
    32 * Provers: improved induct method: assumptions introduced by case
    33 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    34 the goal statement); "foo" still refers to all facts collectively;
    35 
    36 * Isar: preview of problems to finish 'show' now produce an error
    37 rather than just a warning (in interactive mode);
    38 
    39 
    40 *** HOL ***
    41 
    42 * 'typedef' command has new option "open" to suppress the set
    43 definition;
    44 
    45 * functions Min and Max on finite sets have been introduced (theory
    46 Finite_Set);
    47 
    48 * attribute [symmetric] now works for relations as well; it turns
    49 (x,y) : R^-1 into (y,x) : R, and vice versa;
    50 
    51 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    52   In ProofGeneral the counter example appears in the trace buffer.
    53 
    54 * arith(_tac) does now know about div k and mod k where k is a numeral
    55 of type nat or int. It can solve simple goals like
    56 
    57   "0 < n ==> n div 2 < (n::nat)"
    58 
    59 but fails if divisibility plays a role like in
    60 
    61   "n div 2 + (n+1) div 2 = (n::nat)"
    62 
    63 * simp's arithmetic capabilities have been enhanced a bit: it now
    64 takes ~= in premises into account (by performing a case split);
    65 
    66 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands are
    67   distributed over a sum of terms.
    68 
    69 
    70 *** ML ***
    71 
    72 * Pure: Tactic.prove provides sane interface for internal proofs;
    73 omits the infamous "standard" operation, so this is more appropriate
    74 than prove_goalw_cterm in many situations (e.g. in simprocs);
    75 
    76 * Pure: improved error reporting of simprocs;
    77 
    78 * Provers: Simplifier.simproc(_i) provides sane interface for setting
    79 up simprocs;
    80 
    81 
    82 
    83 New in Isabelle2002 (March 2002)
    84 --------------------------------
    85 
    86 *** Document preparation ***
    87 
    88 * greatly simplified document preparation setup, including more
    89 graceful interpretation of isatool usedir -i/-d/-D options, and more
    90 instructive isatool mkdir; users should basically be able to get
    91 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    92 users may run a separate document processing stage manually like this:
    93 "isatool usedir -D output HOL Test && isatool document Test/output";
    94 
    95 * theory dependency graph may now be incorporated into documents;
    96 isatool usedir -g true will produce session_graph.eps/.pdf for use
    97 with \includegraphics of LaTeX;
    98 
    99 * proper spacing of consecutive markup elements, especially text
   100 blocks after section headings;
   101 
   102 * support bold style (for single symbols only), input syntax is like
   103 this: "\<^bold>\<alpha>" or "\<^bold>A";
   104 
   105 * \<bullet> is now output as bold \cdot by default, which looks much
   106 better in printed text;
   107 
   108 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   109 note that these symbols are currently unavailable in Proof General /
   110 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   111 
   112 * isatool latex no longer depends on changed TEXINPUTS, instead
   113 isatool document copies the Isabelle style files to the target
   114 location;
   115 
   116 
   117 *** Isar ***
   118 
   119 * Pure/Provers: improved proof by cases and induction;
   120   - 'case' command admits impromptu naming of parameters (such as
   121     "case (Suc n)");
   122   - 'induct' method divinates rule instantiation from the inductive
   123     claim; no longer requires excessive ?P bindings for proper
   124     instantiation of cases;
   125   - 'induct' method properly enumerates all possibilities of set/type
   126     rules; as a consequence facts may be also passed through *type*
   127     rules without further ado;
   128   - 'induct' method now derives symbolic cases from the *rulified*
   129     rule (before it used to rulify cases stemming from the internal
   130     atomized version); this means that the context of a non-atomic
   131     statement becomes is included in the hypothesis, avoiding the
   132     slightly cumbersome show "PROP ?case" form;
   133   - 'induct' may now use elim-style induction rules without chaining
   134     facts, using ``missing'' premises from the goal state; this allows
   135     rules stemming from inductive sets to be applied in unstructured
   136     scripts, while still benefitting from proper handling of non-atomic
   137     statements; NB: major inductive premises need to be put first, all
   138     the rest of the goal is passed through the induction;
   139   - 'induct' proper support for mutual induction involving non-atomic
   140     rule statements (uses the new concept of simultaneous goals, see
   141     below);
   142   - append all possible rule selections, but only use the first
   143     success (no backtracking);
   144   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   145   - undeclared rule case names default to numbers 1, 2, 3, ...;
   146   - added 'print_induct_rules' (covered by help item in recent Proof
   147     General versions);
   148   - moved induct/cases attributes to Pure, methods to Provers;
   149   - generic method setup instantiated for FOL and HOL;
   150 
   151 * Pure: support multiple simultaneous goal statements, for example
   152 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   153 meta-level mechanism, this acts as if several individual goals had
   154 been stated separately; in particular common proof methods need to be
   155 repeated in order to cover all claims; note that a single elimination
   156 step is *not* sufficient to establish the two conjunctions, so this
   157 fails:
   158 
   159   assume "A & B" then have A and B ..   (*".." fails*)
   160 
   161 better use "obtain" in situations as above; alternative refer to
   162 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   163 
   164 * Pure: proper integration with ``locales''; unlike the original
   165 version by Florian Kammüller, Isar locales package high-level proof
   166 contexts rather than raw logical ones (e.g. we admit to include
   167 attributes everywhere); operations on locales include merge and
   168 rename; support for implicit arguments (``structures''); simultaneous
   169 type-inference over imports and text; see also HOL/ex/Locales.thy for
   170 some examples;
   171 
   172 * Pure: the following commands have been ``localized'', supporting a
   173 target locale specification "(in name)": 'lemma', 'theorem',
   174 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   175 stored both within the locale and at the theory level (exported and
   176 qualified by the locale name);
   177 
   178 * Pure: theory goals may now be specified in ``long'' form, with
   179 ad-hoc contexts consisting of arbitrary locale elements. for example
   180 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   181 definitions may be given, too); the result is a meta-level rule with
   182 the context elements being discharged in the obvious way;
   183 
   184 * Pure: new proof command 'using' allows to augment currently used
   185 facts after a goal statement ('using' is syntactically analogous to
   186 'apply', but acts on the goal's facts only); this allows chained facts
   187 to be separated into parts given before and after a claim, as in
   188 ``from a and b have C using d and e <proof>'';
   189 
   190 * Pure: renamed "antecedent" case to "rule_context";
   191 
   192 * Pure: new 'judgment' command records explicit information about the
   193 object-logic embedding (used by several tools internally); no longer
   194 use hard-wired "Trueprop";
   195 
   196 * Pure: added 'corollary' command;
   197 
   198 * Pure: fixed 'token_translation' command;
   199 
   200 * Pure: removed obsolete 'exported' attribute;
   201 
   202 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   203 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   204 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   205 
   206 * Pure: method 'atomize' presents local goal premises as object-level
   207 statements (atomic meta-level propositions); setup controlled via
   208 rewrite rules declarations of 'atomize' attribute; example
   209 application: 'induct' method with proper rule statements in improper
   210 proof *scripts*;
   211 
   212 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   213 now consider the syntactic context of assumptions, giving a better
   214 chance to get type-inference of the arguments right (this is
   215 especially important for locales);
   216 
   217 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   218 mode;
   219 
   220 * Pure/obtain: the formal conclusion "thesis", being marked as
   221 ``internal'', may no longer be reference directly in the text;
   222 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   223 situations;
   224 
   225 * Pure: generic 'sym' attribute which declares a rule both as pure
   226 'elim?' and for the 'symmetric' operation;
   227 
   228 * Pure: marginal comments ``--'' may now occur just anywhere in the
   229 text; the fixed correlation with particular command syntax has been
   230 discontinued;
   231 
   232 * Pure: new method 'rules' is particularly well-suited for proof
   233 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   234 but often produces more compact proof terms with less detours;
   235 
   236 * Pure/Provers/classical: simplified integration with pure rule
   237 attributes and methods; the classical "intro?/elim?/dest?"
   238 declarations coincide with the pure ones; the "rule" method no longer
   239 includes classically swapped intros; "intro" and "elim" methods no
   240 longer pick rules from the context; also got rid of ML declarations
   241 AddXIs/AddXEs/AddXDs; all of this has some potential for
   242 INCOMPATIBILITY;
   243 
   244 * Provers/classical: attribute 'swapped' produces classical inversions
   245 of introduction rules;
   246 
   247 * Provers/simplifier: 'simplified' attribute may refer to explicit
   248 rules instead of full simplifier context; 'iff' attribute handles
   249 conditional rules;
   250 
   251 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   252 
   253 * HOL: 'recdef' now fails on unfinished automated proofs, use
   254 "(permissive)" option to recover old behavior;
   255 
   256 * HOL: 'inductive' no longer features separate (collective) attributes
   257 for 'intros' (was found too confusing);
   258 
   259 * HOL: properly declared induction rules less_induct and
   260 wf_induct_rule;
   261 
   262 
   263 *** HOL ***
   264 
   265 * HOL: moved over to sane numeral syntax; the new policy is as
   266 follows:
   267 
   268   - 0 and 1 are polymorphic constants, which are defined on any
   269   numeric type (nat, int, real etc.);
   270 
   271   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   272   binary representation internally;
   273 
   274   - type nat has special constructor Suc, and generally prefers Suc 0
   275   over 1::nat and Suc (Suc 0) over 2::nat;
   276 
   277 This change may cause significant problems of INCOMPATIBILITY; here
   278 are some hints on converting existing sources:
   279 
   280   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   281   entities, so expressions involving "-" (unary or binary minus) need
   282   to be spaced properly;
   283 
   284   - existing occurrences of "1" may need to be constraint "1::nat" or
   285   even replaced by Suc 0; similar for old "2";
   286 
   287   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   288 
   289   - remove all special provisions on numerals in proofs;
   290 
   291 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   292 representation (depends on bin_arith_simps in the default context);
   293 
   294 * HOL: symbolic syntax for x^2 (numeral 2);
   295 
   296 * HOL: the class of all HOL types is now called "type" rather than
   297 "term"; INCOMPATIBILITY, need to adapt references to this type class
   298 in axclass/classes, instance/arities, and (usually rare) occurrences
   299 in typings (of consts etc.); internally the class is called
   300 "HOL.type", ML programs should refer to HOLogic.typeS;
   301 
   302 * HOL/record package improvements:
   303   - new derived operations "fields" to build a partial record section,
   304     "extend" to promote a fixed record to a record scheme, and
   305     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   306     declared as simp by default;
   307   - shared operations ("more", "fields", etc.) now need to be always
   308     qualified) --- potential INCOMPATIBILITY;
   309   - removed "make_scheme" operations (use "make" with "extend") --
   310     INCOMPATIBILITY;
   311   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   312   - provides cases/induct rules for use with corresponding Isar
   313     methods (for concrete records, record schemes, concrete more
   314     parts, and schematic more parts -- in that order);
   315   - internal definitions directly based on a light-weight abstract
   316     theory of product types over typedef rather than datatype;
   317 
   318 * HOL: generic code generator for generating executable ML code from
   319 specifications; specific support for HOL constructs such as inductive
   320 datatypes and sets, as well as recursive functions; can be invoked
   321 via 'generate_code' theory section;
   322 
   323 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   324 
   325 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   326 (beware of argument permutation!);
   327 
   328 * HOL: linorder_less_split superseded by linorder_cases;
   329 
   330 * HOL/List: "nodups" renamed to "distinct";
   331 
   332 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   333 to peripheral theory "Hilbert_Choice";
   334 
   335 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   336 in this (rare) case use:
   337 
   338   delSWrapper "split_all_tac"
   339   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   340 
   341 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   342 MAY FAIL;
   343 
   344 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   345 Isabelle's type classes, ^ on functions and relations has too general
   346 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   347 necessary to attach explicit type constraints;
   348 
   349 * HOL/Relation: the prefix name of the infix "O" has been changed from
   350 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   351 renamed accordingly (eg "compI" -> "rel_compI").
   352 
   353 * HOL: syntax translations now work properly with numerals and records
   354 expressions;
   355 
   356 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   357 of "lam" -- INCOMPATIBILITY;
   358 
   359 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   360 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   361 renamed "Product_Type.unit";
   362 
   363 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   364 
   365 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   366 the "cases" method);
   367 
   368 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   369 Florian Kammüller);
   370 
   371 * HOL/IMP: updated and converted to new-style theory format; several
   372 parts turned into readable document, with proper Isar proof texts and
   373 some explanations (by Gerwin Klein);
   374 
   375 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   376 
   377 * HOL-Hyperreal is now a logic image;
   378 
   379 
   380 *** HOLCF ***
   381 
   382 * Isar: consts/constdefs supports mixfix syntax for continuous
   383 operations;
   384 
   385 * Isar: domain package adapted to new-style theory format, e.g. see
   386 HOLCF/ex/Dnat.thy;
   387 
   388 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   389 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   390 lift.induct_tac, always use UU instead of Undef;
   391 
   392 * HOLCF/IMP: updated and converted to new-style theory;
   393 
   394 
   395 *** ZF ***
   396 
   397 * Isar: proper integration of logic-specific tools and packages,
   398 including theory commands '(co)inductive', '(co)datatype',
   399 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   400 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   401 
   402 * theory Main no longer includes AC; for the Axiom of Choice, base
   403 your theory on Main_ZFC;
   404 
   405 * the integer library now covers quotients and remainders, with many
   406 laws relating division to addition, multiplication, etc.;
   407 
   408 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   409 typeless version of the formalism;
   410 
   411 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   412 format;
   413 
   414 * ZF/Induct: new directory for examples of inductive definitions,
   415 including theory Multiset for multiset orderings; converted to
   416 new-style theory format;
   417 
   418 * ZF: many new theorems about lists, ordinals, etc.;
   419 
   420 
   421 *** General ***
   422 
   423 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   424 variable proof controls level of detail: 0 = no proofs (only oracle
   425 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   426 also ref manual for further ML interfaces;
   427 
   428 * Pure/axclass: removed obsolete ML interface
   429 goal_subclass/goal_arity;
   430 
   431 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   432 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   433 separate tokens, so expressions involving minus need to be spaced
   434 properly;
   435 
   436 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   437 rather than "infixl" or "infixr";
   438 
   439 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   440 sort constraint specifications in type inference; e.g. "x::_::foo"
   441 ensures that the type of "x" is of sort "foo" (but not necessarily a
   442 type variable);
   443 
   444 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   445 control output of nested => (types); the default behavior is
   446 "type_brackets";
   447 
   448 * Pure/syntax: builtin parse translation for "_constify" turns valued
   449 tokens into AST constants;
   450 
   451 * Pure/syntax: prefer later declarations of translations and print
   452 translation functions; potential INCOMPATIBILITY: need to reverse
   453 multiple declarations for same syntax element constant;
   454 
   455 * Pure/show_hyps reset by default (in accordance to existing Isar
   456 practice);
   457 
   458 * Provers/classical: renamed addaltern to addafter, addSaltern to
   459 addSafter;
   460 
   461 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   462 as well;
   463 
   464 * system: tested support for MacOS X; should be able to get Isabelle +
   465 Proof General to work in a plain Terminal after installing Poly/ML
   466 (e.g. from the Isabelle distribution area) and GNU bash alone
   467 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   468 support requires further installations, e.g. from
   469 http://fink.sourceforge.net/);
   470 
   471 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   472 
   473 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   474 of 40 MB), cf. ML_OPTIONS;
   475 
   476 * system: Proof General keywords specification is now part of the
   477 Isabelle distribution (see etc/isar-keywords.el);
   478 
   479 * system: support for persistent Proof General sessions (refrain from
   480 outdating all loaded theories on startup); user may create writable
   481 logic images like this: ``isabelle -q HOL Test'';
   482 
   483 * system: smart selection of Isabelle process versus Isabelle
   484 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   485 run both "isabelle" and "Isabelle" even if file names are badly
   486 damaged (executable inspects the case of the first letter of its own
   487 name); added separate "isabelle-process" and "isabelle-interface";
   488 
   489 * system: refrain from any attempt at filtering input streams; no
   490 longer support ``8bit'' encoding of old isabelle font, instead proper
   491 iso-latin characters may now be used; the related isatools
   492 "symbolinput" and "nonascii" have disappeared as well;
   493 
   494 * system: removed old "xterm" interface (the print modes "xterm" and
   495 "xterm_color" are still available for direct use in a suitable
   496 terminal);
   497 
   498 
   499 
   500 New in Isabelle99-2 (February 2001)
   501 -----------------------------------
   502 
   503 *** Overview of INCOMPATIBILITIES ***
   504 
   505 * HOL: please note that theories in the Library and elsewhere often use the
   506 new-style (Isar) format; to refer to their theorems in an ML script you must
   507 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   508 
   509 * HOL: inductive package no longer splits induction rule aggressively,
   510 but only as far as specified by the introductions given; the old
   511 format may be recovered via ML function complete_split_rule or attribute
   512 'split_rule (complete)';
   513 
   514 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   515 gfp_Tarski to gfp_unfold;
   516 
   517 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   518 
   519 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   520 relation); infix "^^" has been renamed "``"; infix "``" has been
   521 renamed "`"; "univalent" has been renamed "single_valued";
   522 
   523 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   524 operation;
   525 
   526 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   527 
   528 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   529 
   530 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   531 consequence, it is no longer monotonic wrt. the local goal context
   532 (which is now passed through the inductive cases);
   533 
   534 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   535 \<gg> to \<ggreater>;
   536 
   537 
   538 *** Document preparation ***
   539 
   540 * \isabellestyle{NAME} selects version of Isabelle output (currently
   541 available: are "it" for near math-mode best-style output, "sl" for
   542 slanted text style, and "tt" for plain type-writer; if no
   543 \isabellestyle command is given, output is according to slanted
   544 type-writer);
   545 
   546 * support sub/super scripts (for single symbols only), input syntax is
   547 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   548 
   549 * some more standard symbols; see Appendix A of the system manual for
   550 the complete list of symbols defined in isabellesym.sty;
   551 
   552 * improved isabelle style files; more abstract symbol implementation
   553 (should now use \isamath{...} and \isatext{...} in custom symbol
   554 definitions);
   555 
   556 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   557 state; Note that presentation of goal states does not conform to
   558 actual human-readable proof documents.  Please do not include goal
   559 states into document output unless you really know what you are doing!
   560 
   561 * proper indentation of antiquoted output with proportional LaTeX
   562 fonts;
   563 
   564 * no_document ML operator temporarily disables LaTeX document
   565 generation;
   566 
   567 * isatool unsymbolize tunes sources for plain ASCII communication;
   568 
   569 
   570 *** Isar ***
   571 
   572 * Pure: Isar now suffers initial goal statements to contain unbound
   573 schematic variables (this does not conform to actual readable proof
   574 documents, due to unpredictable outcome and non-compositional proof
   575 checking); users who know what they are doing may use schematic goals
   576 for Prolog-style synthesis of proven results;
   577 
   578 * Pure: assumption method (an implicit finishing) now handles actual
   579 rules as well;
   580 
   581 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   582 initial goal, declare "that" only as Pure intro (only for single
   583 steps); the "that" rule assumption may now be involved in implicit
   584 finishing, thus ".." becomes a feasible for trivial obtains;
   585 
   586 * Pure: default proof step now includes 'intro_classes'; thus trivial
   587 instance proofs may be performed by "..";
   588 
   589 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   590 statements as well;
   591 
   592 * Pure: more robust selection of calculational rules;
   593 
   594 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   595 rule (as well as the assumption rule);
   596 
   597 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   598 lemmas, using the graph browser tool;
   599 
   600 * Pure: predict failure of "show" in interactive mode;
   601 
   602 * Pure: 'thms_containing' now takes actual terms as arguments;
   603 
   604 * HOL: improved method 'induct' --- now handles non-atomic goals
   605 (potential INCOMPATIBILITY); tuned error handling;
   606 
   607 * HOL: cases and induct rules now provide explicit hints about the
   608 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   609 any remaining facts are inserted into the goal verbatim;
   610 
   611 * HOL: local contexts (aka cases) may now contain term bindings as
   612 well; the 'cases' and 'induct' methods new provide a ?case binding for
   613 the result to be shown in each case;
   614 
   615 * HOL: added 'recdef_tc' command;
   616 
   617 * isatool convert assists in eliminating legacy ML scripts;
   618 
   619 
   620 *** HOL ***
   621 
   622 * HOL/Library: a collection of generic theories to be used together
   623 with main HOL; the theory loader path already includes this directory
   624 by default; the following existing theories have been moved here:
   625 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   626 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   627 
   628 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   629 modelling and verification task performed in Isabelle/HOL +
   630 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   631 
   632 * HOL/Algebra: special summation operator SUM no longer exists, it has
   633 been replaced by setsum; infix 'assoc' now has priority 50 (like
   634 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   635 'domain', this makes the theory consistent with mathematical
   636 literature;
   637 
   638 * HOL basics: added overloaded operations "inverse" and "divide"
   639 (infix "/"), syntax for generic "abs" operation, generic summation
   640 operator \<Sum>;
   641 
   642 * HOL/typedef: simplified package, provide more useful rules (see also
   643 HOL/subset.thy);
   644 
   645 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   646 now expressed as a proper nested rule (old-style tactic scripts may
   647 require atomize_strip_tac to cope with non-atomic premises);
   648 
   649 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   650 to "split_conv" (old name still available for compatibility);
   651 
   652 * HOL: improved concrete syntax for strings (e.g. allows translation
   653 rules with string literals);
   654 
   655 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   656  and Fleuriot's mechanization of analysis, including the transcendental
   657  functions for the reals;
   658 
   659 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   660 
   661 
   662 *** CTT ***
   663 
   664 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   665 "lam" is displayed as TWO lambda-symbols
   666 
   667 * CTT: theory Main now available, containing everything (that is, Bool
   668 and Arith);
   669 
   670 
   671 *** General ***
   672 
   673 * Pure: the Simplifier has been implemented properly as a derived rule
   674 outside of the actual kernel (at last!); the overall performance
   675 penalty in practical applications is about 50%, while reliability of
   676 the Isabelle inference kernel has been greatly improved;
   677 
   678 * print modes "brackets" and "no_brackets" control output of nested =>
   679 (types) and ==> (props); the default behaviour is "brackets";
   680 
   681 * Provers: fast_tac (and friends) now handle actual object-logic rules
   682 as assumptions as well;
   683 
   684 * system: support Poly/ML 4.0;
   685 
   686 * system: isatool install handles KDE version 1 or 2;
   687 
   688 
   689 
   690 New in Isabelle99-1 (October 2000)
   691 ----------------------------------
   692 
   693 *** Overview of INCOMPATIBILITIES ***
   694 
   695 * HOL: simplification of natural numbers is much changed; to partly
   696 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   697 issue the following ML commands:
   698 
   699   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   700   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   701 
   702 * HOL: simplification no longer dives into case-expressions; this is
   703 controlled by "t.weak_case_cong" for each datatype t;
   704 
   705 * HOL: nat_less_induct renamed to less_induct;
   706 
   707 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   708 fixsome to patch .thy and .ML sources automatically;
   709 
   710   select_equality  -> some_equality
   711   select_eq_Ex     -> some_eq_ex
   712   selectI2EX       -> someI2_ex
   713   selectI2         -> someI2
   714   selectI          -> someI
   715   select1_equality -> some1_equality
   716   Eps_sym_eq       -> some_sym_eq_trivial
   717   Eps_eq           -> some_eq_trivial
   718 
   719 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   720 
   721 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   722 instead);
   723 
   724 * HOL: the recursion equations generated by 'recdef' are now called
   725 f.simps instead of f.rules;
   726 
   727 * HOL: qed_spec_mp now also handles bounded ALL as well;
   728 
   729 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   730 sometimes be needed;
   731 
   732 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   733 
   734 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   735 
   736 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   737 product is now "<*>" instead of "Times"; the lexicographic product is
   738 now "<*lex*>" instead of "**";
   739 
   740 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   741 of main HOL, but was unused); better use HOL's datatype package;
   742 
   743 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   744 the old syntax may be recovered as follows:
   745 
   746   syntax (symbols)
   747     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   748       (infixl "\\<oplus>" 100)
   749 
   750 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   751 
   752 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   753 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   754 internally;
   755 
   756 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   757 changed from A/r to A//r;
   758 
   759 * ZF: new treatment of arithmetic (nat & int) may break some old
   760 proofs;
   761 
   762 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   763 rulify -> rule_format, elimify -> elim_format, ...);
   764 
   765 * Isar/Provers: intro/elim/dest attributes changed; renamed
   766 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   767 should have to change intro!! to intro? only); replaced "delrule" by
   768 "rule del";
   769 
   770 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   771 
   772 * Provers: strengthened force_tac by using new first_best_tac;
   773 
   774 * LaTeX document preparation: several changes of isabelle.sty (see
   775 lib/texinputs);
   776 
   777 
   778 *** Document preparation ***
   779 
   780 * formal comments (text blocks etc.) in new-style theories may now
   781 contain antiquotations of thm/prop/term/typ/text to be presented
   782 according to latex print mode; concrete syntax is like this:
   783 @{term[show_types] "f(x) = a + x"};
   784 
   785 * isatool mkdir provides easy setup of Isabelle session directories,
   786 including proper document sources;
   787 
   788 * generated LaTeX sources are now deleted after successful run
   789 (isatool document -c); may retain a copy somewhere else via -D option
   790 of isatool usedir;
   791 
   792 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   793 style files, achieving self-contained LaTeX sources and simplifying
   794 LaTeX debugging;
   795 
   796 * old-style theories now produce (crude) LaTeX output as well;
   797 
   798 * browser info session directories are now self-contained (may be put
   799 on WWW server seperately); improved graphs of nested sessions; removed
   800 graph for 'all sessions';
   801 
   802 * several improvements in isabelle style files; \isabellestyle{it}
   803 produces fake math mode output; \isamarkupheader is now \section by
   804 default; see lib/texinputs/isabelle.sty etc.;
   805 
   806 
   807 *** Isar ***
   808 
   809 * Isar/Pure: local results and corresponding term bindings are now
   810 subject to Hindley-Milner polymorphism (similar to ML); this
   811 accommodates incremental type-inference very nicely;
   812 
   813 * Isar/Pure: new derived language element 'obtain' supports
   814 generalized existence reasoning;
   815 
   816 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   817 support accumulation of results, without applying any rules yet;
   818 useful to collect intermediate results without explicit name
   819 references, and for use with transitivity rules with more than 2
   820 premises;
   821 
   822 * Isar/Pure: scalable support for case-analysis type proofs: new
   823 'case' language element refers to local contexts symbolically, as
   824 produced by certain proof methods; internally, case names are attached
   825 to theorems as "tags";
   826 
   827 * Isar/Pure: theory command 'hide' removes declarations from
   828 class/type/const name spaces;
   829 
   830 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   831 indicate potential overloading;
   832 
   833 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   834 
   835 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   836 "{a,b,c}" instead of {a,b,c};
   837 
   838 * Isar/Pure now provides its own version of intro/elim/dest
   839 attributes; useful for building new logics, but beware of confusion
   840 with the version in Provers/classical;
   841 
   842 * Isar/Pure: the local context of (non-atomic) goals is provided via
   843 case name 'antecedent';
   844 
   845 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   846 to the current context is now done automatically);
   847 
   848 * Isar/Pure: theory command 'method_setup' provides a simple interface
   849 for definining proof methods in ML;
   850 
   851 * Isar/Provers: intro/elim/dest attributes changed; renamed
   852 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   853 most cases, one should have to change intro!! to intro? only);
   854 replaced "delrule" by "rule del";
   855 
   856 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   857 'symmetric' attribute (the latter supercedes [RS sym]);
   858 
   859 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   860 method modifier); 'simp' method: 'only:' modifier removes loopers as
   861 well (including splits);
   862 
   863 * Isar/Provers: Simplifier and Classical methods now support all kind
   864 of modifiers used in the past, including 'cong', 'iff', etc.
   865 
   866 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   867 of Simplifier and Classical reasoner);
   868 
   869 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   870 now support named cases; major packages (inductive, datatype, primrec,
   871 recdef) support case names and properly name parameters;
   872 
   873 * Isar/HOL: new transitivity rules for substitution in inequalities --
   874 monotonicity conditions are extracted to be proven at end of
   875 calculations;
   876 
   877 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   878 method anyway;
   879 
   880 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   881 split_if split_if_asm; datatype package provides theorems foo.splits =
   882 foo.split foo.split_asm for each datatype;
   883 
   884 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   885 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   886 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   887 use "(cases (simplified))" method in proper proof texts);
   888 
   889 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   890 
   891 * Isar: names of theorems etc. may be natural numbers as well;
   892 
   893 * Isar: 'pr' command: optional arguments for goals_limit and
   894 ProofContext.prems_limit; no longer prints theory contexts, but only
   895 proof states;
   896 
   897 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   898 additional print modes to be specified; e.g. "pr(latex)" will print
   899 proof state according to the Isabelle LaTeX style;
   900 
   901 * Isar: improved support for emulating tactic scripts, including proof
   902 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   903 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   904 (for HOL datatypes);
   905 
   906 * Isar: simplified (more robust) goal selection of proof methods: 1st
   907 goal, all goals, or explicit goal specifier (tactic emulation); thus
   908 'proof method scripts' have to be in depth-first order;
   909 
   910 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   911 
   912 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   913 should instead use individual commands for printing items
   914 (print_commands, print_methods etc.);
   915 
   916 * Isar: added 'nothing' --- the empty list of theorems;
   917 
   918 
   919 *** HOL ***
   920 
   921 * HOL/MicroJava: formalization of a fragment of Java, together with a
   922 corresponding virtual machine and a specification of its bytecode
   923 verifier and a lightweight bytecode verifier, including proofs of
   924 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   925 Cornelia Pusch (see also the homepage of project Bali at
   926 http://isabelle.in.tum.de/Bali/);
   927 
   928 * HOL/Algebra: new theory of rings and univariate polynomials, by
   929 Clemens Ballarin;
   930 
   931 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   932 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   933 Rasmussen;
   934 
   935 * HOL/Lattice: fundamental concepts of lattice theory and order
   936 structures, including duals, properties of bounds versus algebraic
   937 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   938 Theorem for complete lattices etc.; may also serve as a demonstration
   939 for abstract algebraic reasoning using axiomatic type classes, and
   940 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   941 
   942 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   943 von Oheimb;
   944 
   945 * HOL/IMPP: extension of IMP with local variables and mutually
   946 recursive procedures, by David von Oheimb;
   947 
   948 * HOL/Lambda: converted into new-style theory and document;
   949 
   950 * HOL/ex/Multiquote: example of multiple nested quotations and
   951 anti-quotations -- basically a generalized version of de-Bruijn
   952 representation; very useful in avoiding lifting of operations;
   953 
   954 * HOL/record: added general record equality rule to simpset; fixed
   955 select-update simplification procedure to handle extended records as
   956 well; admit "r" as field name;
   957 
   958 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   959 other numeric types and also as the identity of groups, rings, etc.;
   960 
   961 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   962 Types nat and int belong to this axclass;
   963 
   964 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   965    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   966    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   967   two terms #m*u and #n*u are replaced by #(m+n)*u
   968     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   969   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   970     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   971 
   972 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   973 powerful prover for predicate logic but knows nothing of clasets; see
   974 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   975 
   976 * HOL: new version of "case_tac" subsumes both boolean case split and
   977 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   978 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   979 
   980 * HOL: simplification no longer dives into case-expressions: only the
   981 selector expression is simplified, but not the remaining arms; to
   982 enable full simplification of case-expressions for datatype t, you may
   983 remove t.weak_case_cong from the simpset, either globally (Delcongs
   984 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   985 
   986 * HOL/recdef: the recursion equations generated by 'recdef' for
   987 function 'f' are now called f.simps instead of f.rules; if all
   988 termination conditions are proved automatically, these simplification
   989 rules are added to the simpset, as in primrec; rules may be named
   990 individually as well, resulting in a separate list of theorems for
   991 each equation;
   992 
   993 * HOL/While is a new theory that provides a while-combinator. It
   994 permits the definition of tail-recursive functions without the
   995 provision of a termination measure. The latter is necessary once the
   996 invariant proof rule for while is applied.
   997 
   998 * HOL: new (overloaded) notation for the set of elements below/above
   999 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1000 
  1001 * HOL: theorems impI, allI, ballI bound as "strip";
  1002 
  1003 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1004 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1005 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1006 
  1007 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1008 
  1009 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1010 main HOL, but was unused);
  1011 
  1012 * HOL: fewer consts declared as global (e.g. have to refer to
  1013 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1014 
  1015 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1016 in case of overlap with user translations (e.g. judgements over
  1017 tuples); (note that the underlying logical represenation is still
  1018 bogus);
  1019 
  1020 
  1021 *** ZF ***
  1022 
  1023 * ZF: simplification automatically cancels common terms in arithmetic
  1024 expressions over nat and int;
  1025 
  1026 * ZF: new treatment of nat to minimize type-checking: all operators
  1027 coerce their operands to a natural number using the function natify,
  1028 making the algebraic laws unconditional;
  1029 
  1030 * ZF: as above, for int: operators coerce their operands to an integer
  1031 using the function intify;
  1032 
  1033 * ZF: the integer library now contains many of the usual laws for the
  1034 orderings, including $<=, and monotonicity laws for $+ and $*;
  1035 
  1036 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1037 simplification;
  1038 
  1039 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1040 to the simplifier and classical reasoner simultaneously;
  1041 
  1042 
  1043 *** General ***
  1044 
  1045 * Provers: blast_tac now handles actual object-logic rules as
  1046 assumptions; note that auto_tac uses blast_tac internally as well;
  1047 
  1048 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1049 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1050 
  1051 * Provers: delrules now handles destruct rules as well (no longer need
  1052 explicit make_elim);
  1053 
  1054 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1055   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1056 use instead the strong form,
  1057   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1058 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1059 from destruct-rules;
  1060 
  1061 * Provers: Simplifier.easy_setup provides a fast path to basic
  1062 Simplifier setup for new object-logics;
  1063 
  1064 * Pure: AST translation rules no longer require constant head on LHS;
  1065 
  1066 * Pure: improved name spaces: ambiguous output is qualified; support
  1067 for hiding of names;
  1068 
  1069 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1070 XSYMBOL_HOME; no longer need to do manual configuration in most
  1071 situations;
  1072 
  1073 * system: compression of ML heaps images may now be controlled via -c
  1074 option of isabelle and isatool usedir (currently only observed by
  1075 Poly/ML);
  1076 
  1077 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1078 useful for remote X11);
  1079 
  1080 * system: provide TAGS file for Isabelle sources;
  1081 
  1082 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1083 order;
  1084 
  1085 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1086 timing flag supersedes proof_timing and Toplevel.trace;
  1087 
  1088 * ML: new combinators |>> and |>>> for incremental transformations
  1089 with secondary results (e.g. certain theory extensions):
  1090 
  1091 * ML: PureThy.add_defs gets additional argument to indicate potential
  1092 overloading (usually false);
  1093 
  1094 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1095 results;
  1096 
  1097 
  1098 
  1099 New in Isabelle99 (October 1999)
  1100 --------------------------------
  1101 
  1102 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1103 
  1104 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1105 are no longer simplified.  (This allows the simplifier to unfold recursive
  1106 functional programs.)  To restore the old behaviour, declare
  1107 
  1108     Delcongs [if_weak_cong];
  1109 
  1110 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1111 complement;
  1112 
  1113 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1114 
  1115 * HOL/datatype: mutual_induct_tac no longer exists --
  1116   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1117 
  1118 * HOL/typedef: fixed type inference for representing set; type
  1119 arguments now have to occur explicitly on the rhs as type constraints;
  1120 
  1121 * ZF: The con_defs part of an inductive definition may no longer refer
  1122 to constants declared in the same theory;
  1123 
  1124 * HOL, ZF: the function mk_cases, generated by the inductive
  1125 definition package, has lost an argument.  To simplify its result, it
  1126 uses the default simpset instead of a supplied list of theorems.
  1127 
  1128 * HOL/List: the constructors of type list are now Nil and Cons;
  1129 
  1130 * Simplifier: the type of the infix ML functions
  1131         setSSolver addSSolver setSolver addSolver
  1132 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1133 for packaging solvers. A solver is created via
  1134         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1135 where the string argument is only a comment.
  1136 
  1137 
  1138 *** Proof tools ***
  1139 
  1140 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1141 decision procedure for linear arithmetic. Currently it is used for
  1142 types `nat', `int', and `real' in HOL (see below); it can, should and
  1143 will be instantiated for other types and logics as well.
  1144 
  1145 * The simplifier now accepts rewrite rules with flexible heads, eg
  1146      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1147   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1148   matching.
  1149 
  1150 
  1151 *** General ***
  1152 
  1153 * New Isabelle/Isar subsystem provides an alternative to traditional
  1154 tactical theorem proving; together with the ProofGeneral/isar user
  1155 interface it offers an interactive environment for developing human
  1156 readable proof documents (Isar == Intelligible semi-automated
  1157 reasoning); for further information see isatool doc isar-ref,
  1158 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1159 
  1160 * improved and simplified presentation of theories: better HTML markup
  1161 (including colors), graph views in several sizes; isatool usedir now
  1162 provides a proper interface for user theories (via -P option); actual
  1163 document preparation based on (PDF)LaTeX is available as well (for
  1164 new-style theories only); see isatool doc system for more information;
  1165 
  1166 * native support for Proof General, both for classic Isabelle and
  1167 Isabelle/Isar;
  1168 
  1169 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1170 using the graph browser tool;
  1171 
  1172 * Isabelle manuals now also available as PDF;
  1173 
  1174 * theory loader rewritten from scratch (may not be fully
  1175 bug-compatible); old loadpath variable has been replaced by show_path,
  1176 add_path, del_path, reset_path functions; new operations such as
  1177 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1178 isatool doc ref);
  1179 
  1180 * improved isatool install: option -k creates KDE application icon,
  1181 option -p DIR installs standalone binaries;
  1182 
  1183 * added ML_PLATFORM setting (useful for cross-platform installations);
  1184 more robust handling of platform specific ML images for SML/NJ;
  1185 
  1186 * the settings environment is now statically scoped, i.e. it is never
  1187 created again in sub-processes invoked from isabelle, isatool, or
  1188 Isabelle;
  1189 
  1190 * path element specification '~~' refers to '$ISABELLE_HOME';
  1191 
  1192 * in locales, the "assumes" and "defines" parts may be omitted if
  1193 empty;
  1194 
  1195 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1196 long arrows);
  1197 
  1198 * new print_mode "HTML";
  1199 
  1200 * new flag show_tags controls display of tags of theorems (which are
  1201 basically just comments that may be attached by some tools);
  1202 
  1203 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1204 mode and goal output format:
  1205 
  1206 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1207 244c244
  1208 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1209 ---
  1210 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1211 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1212 181c181
  1213 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1214 ---
  1215 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1216 
  1217 * function bind_thms stores lists of theorems (cf. bind_thm);
  1218 
  1219 * new shorthand tactics ftac, eatac, datac, fatac;
  1220 
  1221 * qed (and friends) now accept "" as result name; in that case the
  1222 theorem is not stored, but proper checks and presentation of the
  1223 result still apply;
  1224 
  1225 * theorem database now also indexes constants "Trueprop", "all",
  1226 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1227 
  1228 
  1229 *** HOL ***
  1230 
  1231 ** HOL arithmetic **
  1232 
  1233 * There are now decision procedures for linear arithmetic over nat and
  1234 int:
  1235 
  1236 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1237 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1238 are treated as atomic; subformulae not involving type `nat' or `int'
  1239 are ignored; quantified subformulae are ignored unless they are
  1240 positive universal or negative existential. The tactic has to be
  1241 invoked by hand and can be a little bit slow. In particular, the
  1242 running time is exponential in the number of occurrences of `min' and
  1243 `max', and `-' on `nat'.
  1244 
  1245 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1246 (negated) (in)equalities among the premises and the conclusion into
  1247 account (i.e. no compound formulae) and does not know about `min' and
  1248 `max', and `-' on `nat'. It is fast and is used automatically by the
  1249 simplifier.
  1250 
  1251 NB: At the moment, these decision procedures do not cope with mixed
  1252 nat/int formulae where the two parts interact, such as `m < n ==>
  1253 int(m) < int(n)'.
  1254 
  1255 * HOL/Numeral provides a generic theory of numerals (encoded
  1256 efficiently as bit strings); setup for types nat/int/real is in place;
  1257 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1258 int, existing theories and proof scripts may require a few additional
  1259 type constraints;
  1260 
  1261 * integer division and remainder can now be performed on constant
  1262 arguments;
  1263 
  1264 * many properties of integer multiplication, division and remainder
  1265 are now available;
  1266 
  1267 * An interface to the Stanford Validity Checker (SVC) is available through the
  1268 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1269 are proved automatically.  SVC must be installed separately, and its results
  1270 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1271 invocation of the underlying oracle).  For SVC see
  1272   http://verify.stanford.edu/SVC
  1273 
  1274 * IsaMakefile: the HOL-Real target now builds an actual image;
  1275 
  1276 
  1277 ** HOL misc **
  1278 
  1279 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1280 (in Isabelle/Isar) -- by Gertrud Bauer;
  1281 
  1282 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1283 analysis for assembly languages with subtypes;
  1284 
  1285 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1286 -- avoids syntactic ambiguities and treats state, transition, and
  1287 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1288 changed syntax and (many) tactics;
  1289 
  1290 * HOL/inductive: Now also handles more general introduction rules such
  1291   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1292   theorems are now maintained within the theory (maintained via the
  1293   "mono" attribute);
  1294 
  1295 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1296   (using function types) such as
  1297 
  1298   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1299 
  1300 * HOL/record: record_simproc (part of the default simpset) takes care
  1301 of selectors applied to updated records; record_split_tac is no longer
  1302 part of the default claset; update_defs may now be removed from the
  1303 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1304 
  1305   claset_ref () := claset() addSWrapper record_split_wrapper;
  1306   Delsimprocs [record_simproc]
  1307 
  1308 * HOL/typedef: fixed type inference for representing set; type
  1309 arguments now have to occur explicitly on the rhs as type constraints;
  1310 
  1311 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1312 names rather than an ML expression;
  1313 
  1314 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1315 supplied later.  Program schemes can be defined, such as
  1316     "While B C s = (if B s then While B C (C s) else s)"
  1317 where the well-founded relation can be chosen after B and C have been given.
  1318 
  1319 * HOL/List: the constructors of type list are now Nil and Cons;
  1320 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1321 course, ML tools referring to List.list.op # etc. have to be adapted;
  1322 
  1323 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1324 disabled by default; run isabelle with option -m HOL to get back to
  1325 the original Gordon/HOL-style output;
  1326 
  1327 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1328 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1329 
  1330 * HOL basic syntax simplified (more orthogonal): all variants of
  1331 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1332 Eps operator is provided as well: "SOME x. P[x]";
  1333 
  1334 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1335 
  1336 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1337 thus available for user theories;
  1338 
  1339 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1340 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1341 time;
  1342 
  1343 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1344 several times and then mp;
  1345 
  1346 
  1347 *** LK ***
  1348 
  1349 * the notation <<...>> is now available as a notation for sequences of
  1350 formulas;
  1351 
  1352 * the simplifier is now installed
  1353 
  1354 * the axiom system has been generalized (thanks to Soren Heilmann)
  1355 
  1356 * the classical reasoner now has a default rule database
  1357 
  1358 
  1359 *** ZF ***
  1360 
  1361 * new primrec section allows primitive recursive functions to be given
  1362 directly (as in HOL) over datatypes and the natural numbers;
  1363 
  1364 * new tactics induct_tac and exhaust_tac for induction (or case
  1365 analysis) over datatypes and the natural numbers;
  1366 
  1367 * the datatype declaration of type T now defines the recursor T_rec;
  1368 
  1369 * simplification automatically does freeness reasoning for datatype
  1370 constructors;
  1371 
  1372 * automatic type-inference, with AddTCs command to insert new
  1373 type-checking rules;
  1374 
  1375 * datatype introduction rules are now added as Safe Introduction rules
  1376 to the claset;
  1377 
  1378 * the syntax "if P then x else y" is now available in addition to
  1379 if(P,x,y);
  1380 
  1381 
  1382 *** Internal programming interfaces ***
  1383 
  1384 * tuned simplifier trace output; new flag debug_simp;
  1385 
  1386 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1387 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1388 
  1389 * AxClass.axclass_tac lost the theory argument;
  1390 
  1391 * tuned current_goals_markers semantics: begin / end goal avoids
  1392 printing empty lines;
  1393 
  1394 * removed prs and prs_fn hook, which was broken because it did not
  1395 include \n in its semantics, forcing writeln to add one
  1396 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1397 string -> unit if you really want to output text without newline;
  1398 
  1399 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1400 plain output, interface builders may have to enable 'isabelle_font'
  1401 mode to get Isabelle font glyphs as before;
  1402 
  1403 * refined token_translation interface; INCOMPATIBILITY: output length
  1404 now of type real instead of int;
  1405 
  1406 * theory loader actions may be traced via new ThyInfo.add_hook
  1407 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1408 your own database of information attached to *whole* theories -- as
  1409 opposed to intra-theory data slots offered via TheoryDataFun;
  1410 
  1411 * proper handling of dangling sort hypotheses (at last!);
  1412 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1413 extra sort hypotheses that can be witnessed from the type signature;
  1414 the force_strip_shyps flag is gone, any remaining shyps are simply
  1415 left in the theorem (with a warning issued by strip_shyps_warning);
  1416 
  1417 
  1418 
  1419 New in Isabelle98-1 (October 1998)
  1420 ----------------------------------
  1421 
  1422 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1423 
  1424 * several changes of automated proof tools;
  1425 
  1426 * HOL: major changes to the inductive and datatype packages, including
  1427 some minor incompatibilities of theory syntax;
  1428 
  1429 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1430 called `inj_on';
  1431 
  1432 * HOL: removed duplicate thms in Arith:
  1433   less_imp_add_less  should be replaced by  trans_less_add1
  1434   le_imp_add_le      should be replaced by  trans_le_add1
  1435 
  1436 * HOL: unary minus is now overloaded (new type constraints may be
  1437 required);
  1438 
  1439 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1440 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1441 now taken as an integer constant.
  1442 
  1443 * Pure: ML function 'theory_of' renamed to 'theory';
  1444 
  1445 
  1446 *** Proof tools ***
  1447 
  1448 * Simplifier:
  1449   1. Asm_full_simp_tac is now more aggressive.
  1450      1. It will sometimes reorient premises if that increases their power to
  1451         simplify.
  1452      2. It does no longer proceed strictly from left to right but may also
  1453         rotate premises to achieve further simplification.
  1454      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1455      old Asm_full_simp_tac in that it does not rotate premises.
  1456   2. The simplifier now knows a little bit about nat-arithmetic.
  1457 
  1458 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1459 allows for selected deletion of wrappers, by introduction of names for
  1460 wrapper functionals.  This implies that addbefore, addSbefore,
  1461 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1462 and that adding two tactics with the same name overwrites the first
  1463 one (emitting a warning).
  1464   type wrapper = (int -> tactic) -> (int -> tactic)
  1465   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1466   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1467   delWrapper, delSWrapper: claset *  string            -> claset
  1468   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1469 
  1470 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1471 semantics; addbefore now affects only the unsafe part of step_tac
  1472 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1473 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1474 by Force_tac;
  1475 
  1476 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1477 compWrapper; added safe wrapper (and access functions for it);
  1478 
  1479 * HOL/split_all_tac is now much faster and fails if there is nothing
  1480 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1481 and the names of the automatically generated variables have changed.
  1482 split_all_tac has moved within claset() from unsafe wrappers to safe
  1483 wrappers, which means that !!-bound variables are split much more
  1484 aggressively, and safe_tac and clarify_tac now split such variables.
  1485 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1486 Note: the same holds for record_split_tac, which does the job of
  1487 split_all_tac for record fields.
  1488 
  1489 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1490 permanently to the default simpset using Addsplits just like
  1491 Addsimps. They can be removed via Delsplits just like
  1492 Delsimps. Lower-case versions are also available.
  1493 
  1494 * HOL/Simplifier: The rule split_if is now part of the default
  1495 simpset. This means that the simplifier will eliminate all occurrences
  1496 of if-then-else in the conclusion of a goal. To prevent this, you can
  1497 either remove split_if completely from the default simpset by
  1498 `Delsplits [split_if]' or remove it in a specific call of the
  1499 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1500 other case splitting rules to/from the default simpset: every datatype
  1501 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1502 t is the name of the datatype).
  1503 
  1504 * Classical reasoner / Simplifier combination: new force_tac (and
  1505 derivatives Force_tac, force) combines rewriting and classical
  1506 reasoning (and whatever other tools) similarly to auto_tac, but is
  1507 aimed to solve the given subgoal completely.
  1508 
  1509 
  1510 *** General ***
  1511 
  1512 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1513 and `goalw': the theory is no longer needed as an explicit argument -
  1514 the current theory context is used; assumptions are no longer returned
  1515 at the ML-level unless one of them starts with ==> or !!; it is
  1516 recommended to convert to these new commands using isatool fixgoal
  1517 (backup your sources first!);
  1518 
  1519 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1520 the current theory context, and 'theory' to lookup stored theories;
  1521 
  1522 * new theory section 'locale' for declaring constants, assumptions and
  1523 definitions that have local scope;
  1524 
  1525 * new theory section 'nonterminals' for purely syntactic types;
  1526 
  1527 * new theory section 'setup' for generic ML setup functions
  1528 (e.g. package initialization);
  1529 
  1530 * the distribution now includes Isabelle icons: see
  1531 lib/logo/isabelle-{small,tiny}.xpm;
  1532 
  1533 * isatool install - install binaries with absolute references to
  1534 ISABELLE_HOME/bin;
  1535 
  1536 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1537 
  1538 * print mode 'emacs' reserved for Isamode;
  1539 
  1540 * support multiple print (ast) translations per constant name;
  1541 
  1542 * theorems involving oracles are now printed with a suffixed [!];
  1543 
  1544 
  1545 *** HOL ***
  1546 
  1547 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1548 
  1549 * HOL/inductive package reorganized and improved: now supports mutual
  1550 definitions such as
  1551 
  1552   inductive EVEN ODD
  1553     intrs
  1554       null "0 : EVEN"
  1555       oddI "n : EVEN ==> Suc n : ODD"
  1556       evenI "n : ODD ==> Suc n : EVEN"
  1557 
  1558 new theorem list "elims" contains an elimination rule for each of the
  1559 recursive sets; inductive definitions now handle disjunctive premises
  1560 correctly (also ZF);
  1561 
  1562 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1563 "mutual_induct" no longer exists - the induction rule is always
  1564 contained in "induct";
  1565 
  1566 
  1567 * HOL/datatype package re-implemented and greatly improved: now
  1568 supports mutually recursive datatypes such as
  1569 
  1570   datatype
  1571     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1572             | SUM ('a aexp) ('a aexp)
  1573             | DIFF ('a aexp) ('a aexp)
  1574             | NUM 'a
  1575   and
  1576     'a bexp = LESS ('a aexp) ('a aexp)
  1577             | AND ('a bexp) ('a bexp)
  1578             | OR ('a bexp) ('a bexp)
  1579 
  1580 as well as indirectly recursive datatypes such as
  1581 
  1582   datatype
  1583     ('a, 'b) term = Var 'a
  1584                   | App 'b ((('a, 'b) term) list)
  1585 
  1586 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1587 induction on mutually / indirectly recursive datatypes.
  1588 
  1589 Primrec equations are now stored in theory and can be accessed via
  1590 <function_name>.simps.
  1591 
  1592 INCOMPATIBILITIES:
  1593 
  1594   - Theories using datatypes must now have theory Datatype as an
  1595     ancestor.
  1596   - The specific <typename>.induct_tac no longer exists - use the
  1597     generic induct_tac instead.
  1598   - natE has been renamed to nat.exhaust - use exhaust_tac
  1599     instead of res_inst_tac ... natE. Note that the variable
  1600     names in nat.exhaust differ from the names in natE, this
  1601     may cause some "fragile" proofs to fail.
  1602   - The theorems split_<typename>_case and split_<typename>_case_asm
  1603     have been renamed to <typename>.split and <typename>.split_asm.
  1604   - Since default sorts of type variables are now handled correctly,
  1605     some datatype definitions may have to be annotated with explicit
  1606     sort constraints.
  1607   - Primrec definitions no longer require function name and type
  1608     of recursive argument.
  1609 
  1610 Consider using isatool fixdatatype to adapt your theories and proof
  1611 scripts to the new package (backup your sources first!).
  1612 
  1613 
  1614 * HOL/record package: considerably improved implementation; now
  1615 includes concrete syntax for record types, terms, updates; theorems
  1616 for surjective pairing and splitting !!-bound record variables; proof
  1617 support is as follows:
  1618 
  1619   1) standard conversions (selectors or updates applied to record
  1620 constructor terms) are part of the standard simpset;
  1621 
  1622   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1623 made part of standard simpset and claset via addIffs;
  1624 
  1625   3) a tactic for record field splitting (record_split_tac) is part of
  1626 the standard claset (addSWrapper);
  1627 
  1628 To get a better idea about these rules you may retrieve them via
  1629 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1630 the name of your record type.
  1631 
  1632 The split tactic 3) conceptually simplifies by the following rule:
  1633 
  1634   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1635 
  1636 Thus any record variable that is bound by meta-all will automatically
  1637 blow up into some record constructor term, consequently the
  1638 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1639 solve record problems automatically.
  1640 
  1641 
  1642 * reorganized the main HOL image: HOL/Integ and String loaded by
  1643 default; theory Main includes everything;
  1644 
  1645 * automatic simplification of integer sums and comparisons, using cancellation;
  1646 
  1647 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1648 
  1649 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1650 
  1651 * many new identities for unions, intersections, set difference, etc.;
  1652 
  1653 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1654 called split_if, split_split, split_sum_case and split_nat_case (to go
  1655 with add/delsplits);
  1656 
  1657 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1658 (?x::unit) = (); this is made part of the default simpset, which COULD
  1659 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1660 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1661 unit_abs_eta_conv is added in order to counter the effect of
  1662 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1663 %u.f();
  1664 
  1665 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1666 makes more sense);
  1667 
  1668 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1669   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1670   disjointness reasoning but breaking a few old proofs.
  1671 
  1672 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1673 to 'converse' from 'inverse' (for compatibility with ZF and some
  1674 literature);
  1675 
  1676 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1677 the well-founded relation;
  1678 
  1679 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1680     Compl A.  The "Compl" syntax remains available as input syntax for this
  1681     release ONLY.
  1682 
  1683 * HOL/Update: new theory of function updates:
  1684     f(a:=b) == %x. if x=a then b else f x
  1685 may also be iterated as in f(a:=b,c:=d,...);
  1686 
  1687 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1688 
  1689 * HOL/List:
  1690   - new function list_update written xs[i:=v] that updates the i-th
  1691     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1692   - new function `upt' written [i..j(] which generates the list
  1693     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1694     bound write [i..j], which is a shorthand for [i..j+1(].
  1695   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1696 
  1697 * HOL/Arith:
  1698   - removed 'pred' (predecessor) function;
  1699   - generalized some theorems about n-1;
  1700   - many new laws about "div" and "mod";
  1701   - new laws about greatest common divisors (see theory ex/Primes);
  1702 
  1703 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1704 instead of "inverse";
  1705 
  1706 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1707   of the multiset ordering;
  1708 
  1709 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1710   (not included by default);
  1711 
  1712 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1713 
  1714 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1715   programs, i.e. different program variables may have different types.
  1716 
  1717 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1718   [previously, this check worked only if the rewrite rule was unconditional]
  1719   Now rew can involve either definitions or equalities (either == or =).
  1720 
  1721 
  1722 *** ZF ***
  1723 
  1724 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1725   only the theorems proved on ZF.ML;
  1726 
  1727 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1728   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1729   disjointness reasoning but breaking a few old proofs.
  1730 
  1731 * ZF/Update: new theory of function updates
  1732     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1733   may also be iterated as in f(a:=b,c:=d,...);
  1734 
  1735 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1736 
  1737 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1738   [previously, this check worked only if the rewrite rule was unconditional]
  1739   Now rew can involve either definitions or equalities (either == or =).
  1740 
  1741 * case_tac provided for compatibility with HOL
  1742     (like the old excluded_middle_tac, but with subgoals swapped)
  1743 
  1744 
  1745 *** Internal programming interfaces ***
  1746 
  1747 * Pure: several new basic modules made available for general use, see
  1748 also src/Pure/README;
  1749 
  1750 * improved the theory data mechanism to support encapsulation (data
  1751 kind name replaced by private Object.kind, acting as authorization
  1752 key); new type-safe user interface via functor TheoryDataFun; generic
  1753 print_data function becomes basically useless;
  1754 
  1755 * removed global_names compatibility flag -- all theory declarations
  1756 are qualified by default;
  1757 
  1758 * module Pure/Syntax now offers quote / antiquote translation
  1759 functions (useful for Hoare logic etc. with implicit dependencies);
  1760 see HOL/ex/Antiquote for an example use;
  1761 
  1762 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1763 cterm -> thm;
  1764 
  1765 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1766 subgoal;
  1767 
  1768 * Display.print_goals function moved to Locale.print_goals;
  1769 
  1770 * standard print function for goals supports current_goals_markers
  1771 variable for marking begin of proof, end of proof, start of goal; the
  1772 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1773 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1774 for example;
  1775 
  1776 
  1777 
  1778 New in Isabelle98 (January 1998)
  1779 --------------------------------
  1780 
  1781 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1782 
  1783 * changed lexical syntax of terms / types: dots made part of long
  1784 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1785 
  1786 * simpset (and claset) reference variable replaced by functions
  1787 simpset / simpset_ref;
  1788 
  1789 * no longer supports theory aliases (via merge) and non-trivial
  1790 implicit merge of thms' signatures;
  1791 
  1792 * most internal names of constants changed due to qualified names;
  1793 
  1794 * changed Pure/Sequence interface (see Pure/seq.ML);
  1795 
  1796 
  1797 *** General Changes ***
  1798 
  1799 * hierachically structured name spaces (for consts, types, axms, thms
  1800 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1801 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1802 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1803 long_names for fully qualified output names; NOTE: ML programs
  1804 (special tactics, packages etc.) referring to internal names may have
  1805 to be adapted to cope with fully qualified names; in case of severe
  1806 backward campatibility problems try setting 'global_names' at compile
  1807 time to have enrything declared within a flat name space; one may also
  1808 fine tune name declarations in theories via the 'global' and 'local'
  1809 section;
  1810 
  1811 * reimplemented the implicit simpset and claset using the new anytype
  1812 data filed in signatures; references simpset:simpset ref etc. are
  1813 replaced by functions simpset:unit->simpset and
  1814 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1815 to patch your ML files accordingly;
  1816 
  1817 * HTML output now includes theory graph data for display with Java
  1818 applet or isatool browser; data generated automatically via isatool
  1819 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1820 
  1821 * defs may now be conditional; improved rewrite_goals_tac to handle
  1822 conditional equations;
  1823 
  1824 * defs now admits additional type arguments, using TYPE('a) syntax;
  1825 
  1826 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1827 creates a new theory node; implicit merge of thms' signatures is
  1828 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1829 transfer:theory->thm->thm in (rare) cases;
  1830 
  1831 * improved handling of draft signatures / theories; draft thms (and
  1832 ctyps, cterms) are automatically promoted to real ones;
  1833 
  1834 * slightly changed interfaces for oracles: admit many per theory, named
  1835 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1836 
  1837 * print_goals: optional output of const types (set show_consts and
  1838 show_types);
  1839 
  1840 * improved output of warnings (###) and errors (***);
  1841 
  1842 * subgoal_tac displays a warning if the new subgoal has type variables;
  1843 
  1844 * removed old README and Makefiles;
  1845 
  1846 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1847 
  1848 * removed obsolete init_pps and init_database;
  1849 
  1850 * deleted the obsolete tactical STATE, which was declared by
  1851     fun STATE tacfun st = tacfun st st;
  1852 
  1853 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1854 (which abbreviates $HOME);
  1855 
  1856 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1857 use isatool fixseq to adapt your ML programs (this works for fully
  1858 qualified references to the Sequence structure only!);
  1859 
  1860 * use_thy no longer requires writable current directory; it always
  1861 reloads .ML *and* .thy file, if either one is out of date;
  1862 
  1863 
  1864 *** Classical Reasoner ***
  1865 
  1866 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1867 tactics that use classical reasoning to simplify a subgoal without
  1868 splitting it into several subgoals;
  1869 
  1870 * Safe_tac: like safe_tac but uses the default claset;
  1871 
  1872 
  1873 *** Simplifier ***
  1874 
  1875 * added simplification meta rules:
  1876     (asm_)(full_)simplify: simpset -> thm -> thm;
  1877 
  1878 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1879 logics (again);
  1880 
  1881 * added prems argument to simplification procedures;
  1882 
  1883 * HOL, FOL, ZF: added infix function `addsplits':
  1884   instead of `<simpset> setloop (split_tac <thms>)'
  1885   you can simply write `<simpset> addsplits <thms>'
  1886 
  1887 
  1888 *** Syntax ***
  1889 
  1890 * TYPE('a) syntax for type reflection terms;
  1891 
  1892 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1893 
  1894 * pretty printer: changed order of mixfix annotation preference (again!);
  1895 
  1896 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1897 
  1898 
  1899 *** HOL ***
  1900 
  1901 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1902   with `addloop' of the simplifier to faciliate case splitting in premises.
  1903 
  1904 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1905 
  1906 * HOL/Auth: new protocol proofs including some for the Internet
  1907   protocol TLS;
  1908 
  1909 * HOL/Map: new theory of `maps' a la VDM;
  1910 
  1911 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1912 cancelling out common nat summands from =, <, <= (in)equalities, or
  1913 differences; simplification procedures nat_cancel_factor for
  1914 cancelling common factor from =, <, <= (in)equalities over natural
  1915 sums; nat_cancel contains both kinds of procedures, it is installed by
  1916 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1917 
  1918 * HOL/simplifier: terms of the form
  1919   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1920   are rewritten to
  1921   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1922   and those of the form
  1923   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1924   are rewritten to
  1925   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1926 
  1927 * HOL/datatype
  1928   Each datatype `t' now comes with a theorem `split_t_case' 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 
  1936   and a theorem `split_t_case_asm' of the form
  1937 
  1938   P(t_case f1 ... fn x) =
  1939     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1940         ...
  1941        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1942      )
  1943   which can be added to a simpset via `addsplits'. The existing theorems
  1944   expand_list_case and expand_option_case have been renamed to
  1945   split_list_case and split_option_case.
  1946 
  1947 * HOL/Arithmetic:
  1948   - `pred n' is automatically converted to `n-1'.
  1949     Users are strongly encouraged not to use `pred' any longer,
  1950     because it will disappear altogether at some point.
  1951   - Users are strongly encouraged to write "0 < n" rather than
  1952     "n ~= 0". Theorems and proof tools have been modified towards this
  1953     `standard'.
  1954 
  1955 * HOL/Lists:
  1956   the function "set_of_list" has been renamed "set" (and its theorems too);
  1957   the function "nth" now takes its arguments in the reverse order and
  1958   has acquired the infix notation "!" as in "xs!n".
  1959 
  1960 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1961 
  1962 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1963   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1964 
  1965 * HOL/record: extensible records with schematic structural subtyping
  1966 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1967 still lacks various theorems and concrete record syntax;
  1968 
  1969 
  1970 *** HOLCF ***
  1971 
  1972 * removed "axioms" and "generated by" sections;
  1973 
  1974 * replaced "ops" section by extended "consts" section, which is capable of
  1975   handling the continuous function space "->" directly;
  1976 
  1977 * domain package:
  1978   . proves theorems immediately and stores them in the theory,
  1979   . creates hierachical name space,
  1980   . now uses normal mixfix annotations (instead of cinfix...),
  1981   . minor changes to some names and values (for consistency),
  1982   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1983   . separator between mutual domain defs: changed "," to "and",
  1984   . improved handling of sort constraints;  now they have to
  1985     appear on the left-hand side of the equations only;
  1986 
  1987 * fixed LAM <x,y,zs>.b syntax;
  1988 
  1989 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1990 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1991 
  1992 
  1993 *** FOL and ZF ***
  1994 
  1995 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1996   with `addloop' of the simplifier to faciliate case splitting in premises.
  1997 
  1998 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1999 in HOL, they strip ALL and --> from proved theorems;
  2000 
  2001 
  2002 
  2003 New in Isabelle94-8 (May 1997)
  2004 ------------------------------
  2005 
  2006 *** General Changes ***
  2007 
  2008 * new utilities to build / run / maintain Isabelle etc. (in parts
  2009 still somewhat experimental); old Makefiles etc. still functional;
  2010 
  2011 * new 'Isabelle System Manual';
  2012 
  2013 * INSTALL text, together with ./configure and ./build scripts;
  2014 
  2015 * reimplemented type inference for greater efficiency, better error
  2016 messages and clean internal interface;
  2017 
  2018 * prlim command for dealing with lots of subgoals (an easier way of
  2019 setting goals_limit);
  2020 
  2021 
  2022 *** Syntax ***
  2023 
  2024 * supports alternative (named) syntax tables (parser and pretty
  2025 printer); internal interface is provided by add_modesyntax(_i);
  2026 
  2027 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2028 be used in conjunction with the Isabelle symbol font; uses the
  2029 "symbols" syntax table;
  2030 
  2031 * added token_translation interface (may translate name tokens in
  2032 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2033 the current print_mode); IMPORTANT: user print translation functions
  2034 are responsible for marking newly introduced bounds
  2035 (Syntax.mark_boundT);
  2036 
  2037 * token translations for modes "xterm" and "xterm_color" that display
  2038 names in bold, underline etc. or colors (which requires a color
  2039 version of xterm);
  2040 
  2041 * infixes may now be declared with names independent of their syntax;
  2042 
  2043 * added typed_print_translation (like print_translation, but may
  2044 access type of constant);
  2045 
  2046 
  2047 *** Classical Reasoner ***
  2048 
  2049 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2050 some limitations.  Blast_tac...
  2051   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2052   + ignores elimination rules that don't have the correct format
  2053         (the conclusion MUST be a formula variable)
  2054   + ignores types, which can make HOL proofs fail
  2055   + rules must not require higher-order unification, e.g. apply_type in ZF
  2056     [message "Function Var's argument not a bound variable" relates to this]
  2057   + its proof strategy is more general but can actually be slower
  2058 
  2059 * substitution with equality assumptions no longer permutes other
  2060 assumptions;
  2061 
  2062 * minor changes in semantics of addafter (now called addaltern); renamed
  2063 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2064 (and access functions for it);
  2065 
  2066 * improved combination of classical reasoner and simplifier:
  2067   + functions for handling clasimpsets
  2068   + improvement of addss: now the simplifier is called _after_ the
  2069     safe steps.
  2070   + safe variant of addss called addSss: uses safe simplifications
  2071     _during_ the safe steps. It is more complete as it allows multiple
  2072     instantiations of unknowns (e.g. with slow_tac).
  2073 
  2074 *** Simplifier ***
  2075 
  2076 * added interface for simplification procedures (functions that
  2077 produce *proven* rewrite rules on the fly, depending on current
  2078 redex);
  2079 
  2080 * ordering on terms as parameter (used for ordered rewriting);
  2081 
  2082 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2083 
  2084 * the solver is now split into a safe and an unsafe part.
  2085 This should be invisible for the normal user, except that the
  2086 functions setsolver and addsolver have been renamed to setSolver and
  2087 addSolver; added safe_asm_full_simp_tac;
  2088 
  2089 
  2090 *** HOL ***
  2091 
  2092 * a generic induction tactic `induct_tac' which works for all datatypes and
  2093 also for type `nat';
  2094 
  2095 * a generic case distinction tactic `exhaust_tac' which works for all
  2096 datatypes and also for type `nat';
  2097 
  2098 * each datatype comes with a function `size';
  2099 
  2100 * patterns in case expressions allow tuple patterns as arguments to
  2101 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2102 
  2103 * primrec now also works with type nat;
  2104 
  2105 * recdef: a new declaration form, allows general recursive functions to be
  2106 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2107 
  2108 * the constant for negation has been renamed from "not" to "Not" to
  2109 harmonize with FOL, ZF, LK, etc.;
  2110 
  2111 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2112 infinite lists;
  2113 
  2114 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2115 
  2116 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2117 problems in commutative rings, using axiomatic type classes for + and *;
  2118 
  2119 * more examples in HOL/MiniML and HOL/Auth;
  2120 
  2121 * more default rewrite rules for quantifiers, union/intersection;
  2122 
  2123 * a new constant `arbitrary == @x.False';
  2124 
  2125 * HOLCF/IOA replaces old HOL/IOA;
  2126 
  2127 * HOLCF changes: derived all rules and arities
  2128   + axiomatic type classes instead of classes
  2129   + typedef instead of faking type definitions
  2130   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2131   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2132   + eliminated the types void, one, tr
  2133   + use unit lift and bool lift (with translations) instead of one and tr
  2134   + eliminated blift from Lift3.thy (use Def instead of blift)
  2135   all eliminated rules are derived as theorems --> no visible changes ;
  2136 
  2137 
  2138 *** ZF ***
  2139 
  2140 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2141 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2142 as ZF_cs addSIs [equalityI];
  2143 
  2144 
  2145 
  2146 New in Isabelle94-7 (November 96)
  2147 ---------------------------------
  2148 
  2149 * allowing negative levels (as offsets) in prlev and choplev;
  2150 
  2151 * super-linear speedup for large simplifications;
  2152 
  2153 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2154 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2155 FAIL); can suppress it using the command Delsimps (ex_simps @
  2156 all_simps); De Morgan laws are also now included, by default;
  2157 
  2158 * improved printing of ==>  :  ~:
  2159 
  2160 * new object-logic "Sequents" adds linear logic, while replacing LK
  2161 and Modal (thanks to Sara Kalvala);
  2162 
  2163 * HOL/Auth: correctness proofs for authentication protocols;
  2164 
  2165 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2166 examples on HOL/Auth);
  2167 
  2168 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2169 the rewriter and classical reasoner simultaneously;
  2170 
  2171 * function uresult no longer returns theorems in "standard" format;
  2172 regain previous version by: val uresult = standard o uresult;
  2173 
  2174 
  2175 
  2176 New in Isabelle94-6
  2177 -------------------
  2178 
  2179 * oracles -- these establish an interface between Isabelle and trusted
  2180 external reasoners, which may deliver results as theorems;
  2181 
  2182 * proof objects (in particular record all uses of oracles);
  2183 
  2184 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2185 
  2186 * "constdefs" section in theory files;
  2187 
  2188 * "primrec" section (HOL) no longer requires names;
  2189 
  2190 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2191 
  2192 
  2193 
  2194 New in Isabelle94-5
  2195 -------------------
  2196 
  2197 * reduced space requirements;
  2198 
  2199 * automatic HTML generation from theories;
  2200 
  2201 * theory files no longer require "..." (quotes) around most types;
  2202 
  2203 * new examples, including two proofs of the Church-Rosser theorem;
  2204 
  2205 * non-curried (1994) version of HOL is no longer distributed;
  2206 
  2207 
  2208 
  2209 New in Isabelle94-4
  2210 -------------------
  2211 
  2212 * greatly reduced space requirements;
  2213 
  2214 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2215 
  2216 * searchable theorem database (see the section "Retrieving theorems" on
  2217 page 8 of the Reference Manual);
  2218 
  2219 * new examples, including Grabczewski's monumental case study of the
  2220 Axiom of Choice;
  2221 
  2222 * The previous version of HOL renamed to Old_HOL;
  2223 
  2224 * The new version of HOL (previously called CHOL) uses a curried syntax
  2225 for functions.  Application looks like f a b instead of f(a,b);
  2226 
  2227 * Mutually recursive inductive definitions finally work in HOL;
  2228 
  2229 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2230 translates to the operator "split";
  2231 
  2232 
  2233 
  2234 New in Isabelle94-3
  2235 -------------------
  2236 
  2237 * new infix operator, addss, allowing the classical reasoner to
  2238 perform simplification at each step of its search.  Example:
  2239         fast_tac (cs addss ss)
  2240 
  2241 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2242 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2243 look like (a,b) instead of <a,b>;
  2244 
  2245 * PLEASE NOTE: CHOL will eventually replace HOL!
  2246 
  2247 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2248 It translates to the operator "split".  A new theory of integers is available;
  2249 
  2250 * In ZF, integer numerals now denote two's-complement binary integers.
  2251 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2252 
  2253 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2254 of the Axiom of Choice;
  2255 
  2256 
  2257 
  2258 New in Isabelle94-2
  2259 -------------------
  2260 
  2261 * Significantly faster resolution;
  2262 
  2263 * the different sections in a .thy file can now be mixed and repeated
  2264 freely;
  2265 
  2266 * Database of theorems for FOL, HOL and ZF.  New
  2267 commands including qed, qed_goal and bind_thm store theorems in the database.
  2268 
  2269 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2270 a given theory (thms_of), or find out what theory a theorem was proved in
  2271 (theory_of_thm);
  2272 
  2273 * Bugs fixed in the inductive definition and datatype packages;
  2274 
  2275 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2276 and HOL_dup_cs obsolete;
  2277 
  2278 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2279 have been removed;
  2280 
  2281 * Simpler definition of function space in ZF;
  2282 
  2283 * new results about cardinal and ordinal arithmetic in ZF;
  2284 
  2285 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2286 types;
  2287 
  2288 
  2289 $Id$