NEWS
author wenzelm
Tue Aug 27 16:41:52 2002 +0200 (2002-08-27)
changeset 13540 aede0306e214
parent 13522 934fffeb6f38
child 13541 44efea0e21fa
permissions -rw-r--r--
* Pure: disallow duplicate fact bindings within new-style theory files;
     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); an optional limit for the number of printed facts may be
    26 given (the default is 40);
    27 
    28 * Pure: disallow duplicate fact bindings within new-style theory
    29 files;
    30 
    31 * Provers: improved induct method: assumptions introduced by case
    32 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    33 the goal statement); "foo" still refers to all facts collectively;
    34 
    35 * Isar: preview of problems to finish 'show' now produce an error
    36 rather than just a warning (in interactive mode);
    37 
    38 
    39 *** HOL ***
    40 
    41 * 'typedef' command has new option "open" to suppress the set
    42 definition;
    43 
    44 * functions Min and Max on finite sets have been introduced (theory
    45 Finite_Set);
    46 
    47 * attribute [symmetric] now works for relations as well; it turns
    48 (x,y) : R^-1 into (y,x) : R, and vice versa;
    49 
    50 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    51   In ProofGeneral the counter example appears in the trace buffer.
    52 
    53 * arith(_tac) does now know about div k and mod k where k is a numeral
    54 of type nat or int. It can solve simple goals like
    55 
    56   "0 < n ==> n div 2 < (n::nat)"
    57 
    58 but fails if divisibility plays a role like in
    59 
    60   "n div 2 + (n+1) div 2 = (n::nat)"
    61 
    62 * simp's arithmetic capabilities have been enhanced a bit: it now
    63 takes ~= in premises into account (by performing a case split);
    64 
    65 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands are
    66   distributed over a sum of terms.
    67 
    68 
    69 *** ML ***
    70 
    71 * Pure: Tactic.prove provides sane interface for internal proofs;
    72 omits the infamous "standard" operation, so this is more appropriate
    73 than prove_goalw_cterm in many situations (e.g. in simprocs);
    74 
    75 * Pure: improved error reporting of simprocs;
    76 
    77 * Provers: Simplifier.simproc(_i) provides sane interface for setting
    78 up simprocs;
    79 
    80 
    81 
    82 New in Isabelle2002 (March 2002)
    83 --------------------------------
    84 
    85 *** Document preparation ***
    86 
    87 * greatly simplified document preparation setup, including more
    88 graceful interpretation of isatool usedir -i/-d/-D options, and more
    89 instructive isatool mkdir; users should basically be able to get
    90 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    91 users may run a separate document processing stage manually like this:
    92 "isatool usedir -D output HOL Test && isatool document Test/output";
    93 
    94 * theory dependency graph may now be incorporated into documents;
    95 isatool usedir -g true will produce session_graph.eps/.pdf for use
    96 with \includegraphics of LaTeX;
    97 
    98 * proper spacing of consecutive markup elements, especially text
    99 blocks after section headings;
   100 
   101 * support bold style (for single symbols only), input syntax is like
   102 this: "\<^bold>\<alpha>" or "\<^bold>A";
   103 
   104 * \<bullet> is now output as bold \cdot by default, which looks much
   105 better in printed text;
   106 
   107 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   108 note that these symbols are currently unavailable in Proof General /
   109 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   110 
   111 * isatool latex no longer depends on changed TEXINPUTS, instead
   112 isatool document copies the Isabelle style files to the target
   113 location;
   114 
   115 
   116 *** Isar ***
   117 
   118 * Pure/Provers: improved proof by cases and induction;
   119   - 'case' command admits impromptu naming of parameters (such as
   120     "case (Suc n)");
   121   - 'induct' method divinates rule instantiation from the inductive
   122     claim; no longer requires excessive ?P bindings for proper
   123     instantiation of cases;
   124   - 'induct' method properly enumerates all possibilities of set/type
   125     rules; as a consequence facts may be also passed through *type*
   126     rules without further ado;
   127   - 'induct' method now derives symbolic cases from the *rulified*
   128     rule (before it used to rulify cases stemming from the internal
   129     atomized version); this means that the context of a non-atomic
   130     statement becomes is included in the hypothesis, avoiding the
   131     slightly cumbersome show "PROP ?case" form;
   132   - 'induct' may now use elim-style induction rules without chaining
   133     facts, using ``missing'' premises from the goal state; this allows
   134     rules stemming from inductive sets to be applied in unstructured
   135     scripts, while still benefitting from proper handling of non-atomic
   136     statements; NB: major inductive premises need to be put first, all
   137     the rest of the goal is passed through the induction;
   138   - 'induct' proper support for mutual induction involving non-atomic
   139     rule statements (uses the new concept of simultaneous goals, see
   140     below);
   141   - append all possible rule selections, but only use the first
   142     success (no backtracking);
   143   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   144   - undeclared rule case names default to numbers 1, 2, 3, ...;
   145   - added 'print_induct_rules' (covered by help item in recent Proof
   146     General versions);
   147   - moved induct/cases attributes to Pure, methods to Provers;
   148   - generic method setup instantiated for FOL and HOL;
   149 
   150 * Pure: support multiple simultaneous goal statements, for example
   151 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   152 meta-level mechanism, this acts as if several individual goals had
   153 been stated separately; in particular common proof methods need to be
   154 repeated in order to cover all claims; note that a single elimination
   155 step is *not* sufficient to establish the two conjunctions, so this
   156 fails:
   157 
   158   assume "A & B" then have A and B ..   (*".." fails*)
   159 
   160 better use "obtain" in situations as above; alternative refer to
   161 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   162 
   163 * Pure: proper integration with ``locales''; unlike the original
   164 version by Florian Kammüller, Isar locales package high-level proof
   165 contexts rather than raw logical ones (e.g. we admit to include
   166 attributes everywhere); operations on locales include merge and
   167 rename; support for implicit arguments (``structures''); simultaneous
   168 type-inference over imports and text; see also HOL/ex/Locales.thy for
   169 some examples;
   170 
   171 * Pure: the following commands have been ``localized'', supporting a
   172 target locale specification "(in name)": 'lemma', 'theorem',
   173 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   174 stored both within the locale and at the theory level (exported and
   175 qualified by the locale name);
   176 
   177 * Pure: theory goals may now be specified in ``long'' form, with
   178 ad-hoc contexts consisting of arbitrary locale elements. for example
   179 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   180 definitions may be given, too); the result is a meta-level rule with
   181 the context elements being discharged in the obvious way;
   182 
   183 * Pure: new proof command 'using' allows to augment currently used
   184 facts after a goal statement ('using' is syntactically analogous to
   185 'apply', but acts on the goal's facts only); this allows chained facts
   186 to be separated into parts given before and after a claim, as in
   187 ``from a and b have C using d and e <proof>'';
   188 
   189 * Pure: renamed "antecedent" case to "rule_context";
   190 
   191 * Pure: new 'judgment' command records explicit information about the
   192 object-logic embedding (used by several tools internally); no longer
   193 use hard-wired "Trueprop";
   194 
   195 * Pure: added 'corollary' command;
   196 
   197 * Pure: fixed 'token_translation' command;
   198 
   199 * Pure: removed obsolete 'exported' attribute;
   200 
   201 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   202 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   203 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   204 
   205 * Pure: method 'atomize' presents local goal premises as object-level
   206 statements (atomic meta-level propositions); setup controlled via
   207 rewrite rules declarations of 'atomize' attribute; example
   208 application: 'induct' method with proper rule statements in improper
   209 proof *scripts*;
   210 
   211 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   212 now consider the syntactic context of assumptions, giving a better
   213 chance to get type-inference of the arguments right (this is
   214 especially important for locales);
   215 
   216 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   217 mode;
   218 
   219 * Pure/obtain: the formal conclusion "thesis", being marked as
   220 ``internal'', may no longer be reference directly in the text;
   221 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   222 situations;
   223 
   224 * Pure: generic 'sym' attribute which declares a rule both as pure
   225 'elim?' and for the 'symmetric' operation;
   226 
   227 * Pure: marginal comments ``--'' may now occur just anywhere in the
   228 text; the fixed correlation with particular command syntax has been
   229 discontinued;
   230 
   231 * Pure: new method 'rules' is particularly well-suited for proof
   232 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   233 but often produces more compact proof terms with less detours;
   234 
   235 * Pure/Provers/classical: simplified integration with pure rule
   236 attributes and methods; the classical "intro?/elim?/dest?"
   237 declarations coincide with the pure ones; the "rule" method no longer
   238 includes classically swapped intros; "intro" and "elim" methods no
   239 longer pick rules from the context; also got rid of ML declarations
   240 AddXIs/AddXEs/AddXDs; all of this has some potential for
   241 INCOMPATIBILITY;
   242 
   243 * Provers/classical: attribute 'swapped' produces classical inversions
   244 of introduction rules;
   245 
   246 * Provers/simplifier: 'simplified' attribute may refer to explicit
   247 rules instead of full simplifier context; 'iff' attribute handles
   248 conditional rules;
   249 
   250 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   251 
   252 * HOL: 'recdef' now fails on unfinished automated proofs, use
   253 "(permissive)" option to recover old behavior;
   254 
   255 * HOL: 'inductive' no longer features separate (collective) attributes
   256 for 'intros' (was found too confusing);
   257 
   258 * HOL: properly declared induction rules less_induct and
   259 wf_induct_rule;
   260 
   261 
   262 *** HOL ***
   263 
   264 * HOL: moved over to sane numeral syntax; the new policy is as
   265 follows:
   266 
   267   - 0 and 1 are polymorphic constants, which are defined on any
   268   numeric type (nat, int, real etc.);
   269 
   270   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   271   binary representation internally;
   272 
   273   - type nat has special constructor Suc, and generally prefers Suc 0
   274   over 1::nat and Suc (Suc 0) over 2::nat;
   275 
   276 This change may cause significant problems of INCOMPATIBILITY; here
   277 are some hints on converting existing sources:
   278 
   279   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   280   entities, so expressions involving "-" (unary or binary minus) need
   281   to be spaced properly;
   282 
   283   - existing occurrences of "1" may need to be constraint "1::nat" or
   284   even replaced by Suc 0; similar for old "2";
   285 
   286   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   287 
   288   - remove all special provisions on numerals in proofs;
   289 
   290 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   291 representation (depends on bin_arith_simps in the default context);
   292 
   293 * HOL: symbolic syntax for x^2 (numeral 2);
   294 
   295 * HOL: the class of all HOL types is now called "type" rather than
   296 "term"; INCOMPATIBILITY, need to adapt references to this type class
   297 in axclass/classes, instance/arities, and (usually rare) occurrences
   298 in typings (of consts etc.); internally the class is called
   299 "HOL.type", ML programs should refer to HOLogic.typeS;
   300 
   301 * HOL/record package improvements:
   302   - new derived operations "fields" to build a partial record section,
   303     "extend" to promote a fixed record to a record scheme, and
   304     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   305     declared as simp by default;
   306   - shared operations ("more", "fields", etc.) now need to be always
   307     qualified) --- potential INCOMPATIBILITY;
   308   - removed "make_scheme" operations (use "make" with "extend") --
   309     INCOMPATIBILITY;
   310   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   311   - provides cases/induct rules for use with corresponding Isar
   312     methods (for concrete records, record schemes, concrete more
   313     parts, and schematic more parts -- in that order);
   314   - internal definitions directly based on a light-weight abstract
   315     theory of product types over typedef rather than datatype;
   316 
   317 * HOL: generic code generator for generating executable ML code from
   318 specifications; specific support for HOL constructs such as inductive
   319 datatypes and sets, as well as recursive functions; can be invoked
   320 via 'generate_code' theory section;
   321 
   322 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   323 
   324 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   325 (beware of argument permutation!);
   326 
   327 * HOL: linorder_less_split superseded by linorder_cases;
   328 
   329 * HOL/List: "nodups" renamed to "distinct";
   330 
   331 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   332 to peripheral theory "Hilbert_Choice";
   333 
   334 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   335 in this (rare) case use:
   336 
   337   delSWrapper "split_all_tac"
   338   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   339 
   340 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   341 MAY FAIL;
   342 
   343 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   344 Isabelle's type classes, ^ on functions and relations has too general
   345 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   346 necessary to attach explicit type constraints;
   347 
   348 * HOL/Relation: the prefix name of the infix "O" has been changed from
   349 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   350 renamed accordingly (eg "compI" -> "rel_compI").
   351 
   352 * HOL: syntax translations now work properly with numerals and records
   353 expressions;
   354 
   355 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   356 of "lam" -- INCOMPATIBILITY;
   357 
   358 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   359 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   360 renamed "Product_Type.unit";
   361 
   362 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   363 
   364 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   365 the "cases" method);
   366 
   367 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   368 Florian Kammüller);
   369 
   370 * HOL/IMP: updated and converted to new-style theory format; several
   371 parts turned into readable document, with proper Isar proof texts and
   372 some explanations (by Gerwin Klein);
   373 
   374 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   375 
   376 * HOL-Hyperreal is now a logic image;
   377 
   378 
   379 *** HOLCF ***
   380 
   381 * Isar: consts/constdefs supports mixfix syntax for continuous
   382 operations;
   383 
   384 * Isar: domain package adapted to new-style theory format, e.g. see
   385 HOLCF/ex/Dnat.thy;
   386 
   387 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   388 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   389 lift.induct_tac, always use UU instead of Undef;
   390 
   391 * HOLCF/IMP: updated and converted to new-style theory;
   392 
   393 
   394 *** ZF ***
   395 
   396 * Isar: proper integration of logic-specific tools and packages,
   397 including theory commands '(co)inductive', '(co)datatype',
   398 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   399 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   400 
   401 * theory Main no longer includes AC; for the Axiom of Choice, base
   402 your theory on Main_ZFC;
   403 
   404 * the integer library now covers quotients and remainders, with many
   405 laws relating division to addition, multiplication, etc.;
   406 
   407 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   408 typeless version of the formalism;
   409 
   410 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   411 format;
   412 
   413 * ZF/Induct: new directory for examples of inductive definitions,
   414 including theory Multiset for multiset orderings; converted to
   415 new-style theory format;
   416 
   417 * ZF: many new theorems about lists, ordinals, etc.;
   418 
   419 
   420 *** General ***
   421 
   422 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   423 variable proof controls level of detail: 0 = no proofs (only oracle
   424 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   425 also ref manual for further ML interfaces;
   426 
   427 * Pure/axclass: removed obsolete ML interface
   428 goal_subclass/goal_arity;
   429 
   430 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   431 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   432 separate tokens, so expressions involving minus need to be spaced
   433 properly;
   434 
   435 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   436 rather than "infixl" or "infixr";
   437 
   438 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   439 sort constraint specifications in type inference; e.g. "x::_::foo"
   440 ensures that the type of "x" is of sort "foo" (but not necessarily a
   441 type variable);
   442 
   443 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   444 control output of nested => (types); the default behavior is
   445 "type_brackets";
   446 
   447 * Pure/syntax: builtin parse translation for "_constify" turns valued
   448 tokens into AST constants;
   449 
   450 * Pure/syntax: prefer later declarations of translations and print
   451 translation functions; potential INCOMPATIBILITY: need to reverse
   452 multiple declarations for same syntax element constant;
   453 
   454 * Pure/show_hyps reset by default (in accordance to existing Isar
   455 practice);
   456 
   457 * Provers/classical: renamed addaltern to addafter, addSaltern to
   458 addSafter;
   459 
   460 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   461 as well;
   462 
   463 * system: tested support for MacOS X; should be able to get Isabelle +
   464 Proof General to work in a plain Terminal after installing Poly/ML
   465 (e.g. from the Isabelle distribution area) and GNU bash alone
   466 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   467 support requires further installations, e.g. from
   468 http://fink.sourceforge.net/);
   469 
   470 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   471 
   472 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   473 of 40 MB), cf. ML_OPTIONS;
   474 
   475 * system: Proof General keywords specification is now part of the
   476 Isabelle distribution (see etc/isar-keywords.el);
   477 
   478 * system: support for persistent Proof General sessions (refrain from
   479 outdating all loaded theories on startup); user may create writable
   480 logic images like this: ``isabelle -q HOL Test'';
   481 
   482 * system: smart selection of Isabelle process versus Isabelle
   483 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   484 run both "isabelle" and "Isabelle" even if file names are badly
   485 damaged (executable inspects the case of the first letter of its own
   486 name); added separate "isabelle-process" and "isabelle-interface";
   487 
   488 * system: refrain from any attempt at filtering input streams; no
   489 longer support ``8bit'' encoding of old isabelle font, instead proper
   490 iso-latin characters may now be used; the related isatools
   491 "symbolinput" and "nonascii" have disappeared as well;
   492 
   493 * system: removed old "xterm" interface (the print modes "xterm" and
   494 "xterm_color" are still available for direct use in a suitable
   495 terminal);
   496 
   497 
   498 
   499 New in Isabelle99-2 (February 2001)
   500 -----------------------------------
   501 
   502 *** Overview of INCOMPATIBILITIES ***
   503 
   504 * HOL: please note that theories in the Library and elsewhere often use the
   505 new-style (Isar) format; to refer to their theorems in an ML script you must
   506 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   507 
   508 * HOL: inductive package no longer splits induction rule aggressively,
   509 but only as far as specified by the introductions given; the old
   510 format may be recovered via ML function complete_split_rule or attribute
   511 'split_rule (complete)';
   512 
   513 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   514 gfp_Tarski to gfp_unfold;
   515 
   516 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   517 
   518 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   519 relation); infix "^^" has been renamed "``"; infix "``" has been
   520 renamed "`"; "univalent" has been renamed "single_valued";
   521 
   522 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   523 operation;
   524 
   525 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   526 
   527 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   528 
   529 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   530 consequence, it is no longer monotonic wrt. the local goal context
   531 (which is now passed through the inductive cases);
   532 
   533 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   534 \<gg> to \<ggreater>;
   535 
   536 
   537 *** Document preparation ***
   538 
   539 * \isabellestyle{NAME} selects version of Isabelle output (currently
   540 available: are "it" for near math-mode best-style output, "sl" for
   541 slanted text style, and "tt" for plain type-writer; if no
   542 \isabellestyle command is given, output is according to slanted
   543 type-writer);
   544 
   545 * support sub/super scripts (for single symbols only), input syntax is
   546 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   547 
   548 * some more standard symbols; see Appendix A of the system manual for
   549 the complete list of symbols defined in isabellesym.sty;
   550 
   551 * improved isabelle style files; more abstract symbol implementation
   552 (should now use \isamath{...} and \isatext{...} in custom symbol
   553 definitions);
   554 
   555 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   556 state; Note that presentation of goal states does not conform to
   557 actual human-readable proof documents.  Please do not include goal
   558 states into document output unless you really know what you are doing!
   559 
   560 * proper indentation of antiquoted output with proportional LaTeX
   561 fonts;
   562 
   563 * no_document ML operator temporarily disables LaTeX document
   564 generation;
   565 
   566 * isatool unsymbolize tunes sources for plain ASCII communication;
   567 
   568 
   569 *** Isar ***
   570 
   571 * Pure: Isar now suffers initial goal statements to contain unbound
   572 schematic variables (this does not conform to actual readable proof
   573 documents, due to unpredictable outcome and non-compositional proof
   574 checking); users who know what they are doing may use schematic goals
   575 for Prolog-style synthesis of proven results;
   576 
   577 * Pure: assumption method (an implicit finishing) now handles actual
   578 rules as well;
   579 
   580 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   581 initial goal, declare "that" only as Pure intro (only for single
   582 steps); the "that" rule assumption may now be involved in implicit
   583 finishing, thus ".." becomes a feasible for trivial obtains;
   584 
   585 * Pure: default proof step now includes 'intro_classes'; thus trivial
   586 instance proofs may be performed by "..";
   587 
   588 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   589 statements as well;
   590 
   591 * Pure: more robust selection of calculational rules;
   592 
   593 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   594 rule (as well as the assumption rule);
   595 
   596 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   597 lemmas, using the graph browser tool;
   598 
   599 * Pure: predict failure of "show" in interactive mode;
   600 
   601 * Pure: 'thms_containing' now takes actual terms as arguments;
   602 
   603 * HOL: improved method 'induct' --- now handles non-atomic goals
   604 (potential INCOMPATIBILITY); tuned error handling;
   605 
   606 * HOL: cases and induct rules now provide explicit hints about the
   607 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   608 any remaining facts are inserted into the goal verbatim;
   609 
   610 * HOL: local contexts (aka cases) may now contain term bindings as
   611 well; the 'cases' and 'induct' methods new provide a ?case binding for
   612 the result to be shown in each case;
   613 
   614 * HOL: added 'recdef_tc' command;
   615 
   616 * isatool convert assists in eliminating legacy ML scripts;
   617 
   618 
   619 *** HOL ***
   620 
   621 * HOL/Library: a collection of generic theories to be used together
   622 with main HOL; the theory loader path already includes this directory
   623 by default; the following existing theories have been moved here:
   624 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   625 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   626 
   627 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   628 modelling and verification task performed in Isabelle/HOL +
   629 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   630 
   631 * HOL/Algebra: special summation operator SUM no longer exists, it has
   632 been replaced by setsum; infix 'assoc' now has priority 50 (like
   633 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   634 'domain', this makes the theory consistent with mathematical
   635 literature;
   636 
   637 * HOL basics: added overloaded operations "inverse" and "divide"
   638 (infix "/"), syntax for generic "abs" operation, generic summation
   639 operator \<Sum>;
   640 
   641 * HOL/typedef: simplified package, provide more useful rules (see also
   642 HOL/subset.thy);
   643 
   644 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   645 now expressed as a proper nested rule (old-style tactic scripts may
   646 require atomize_strip_tac to cope with non-atomic premises);
   647 
   648 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   649 to "split_conv" (old name still available for compatibility);
   650 
   651 * HOL: improved concrete syntax for strings (e.g. allows translation
   652 rules with string literals);
   653 
   654 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   655  and Fleuriot's mechanization of analysis, including the transcendental
   656  functions for the reals;
   657 
   658 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   659 
   660 
   661 *** CTT ***
   662 
   663 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   664 "lam" is displayed as TWO lambda-symbols
   665 
   666 * CTT: theory Main now available, containing everything (that is, Bool
   667 and Arith);
   668 
   669 
   670 *** General ***
   671 
   672 * Pure: the Simplifier has been implemented properly as a derived rule
   673 outside of the actual kernel (at last!); the overall performance
   674 penalty in practical applications is about 50%, while reliability of
   675 the Isabelle inference kernel has been greatly improved;
   676 
   677 * print modes "brackets" and "no_brackets" control output of nested =>
   678 (types) and ==> (props); the default behaviour is "brackets";
   679 
   680 * Provers: fast_tac (and friends) now handle actual object-logic rules
   681 as assumptions as well;
   682 
   683 * system: support Poly/ML 4.0;
   684 
   685 * system: isatool install handles KDE version 1 or 2;
   686 
   687 
   688 
   689 New in Isabelle99-1 (October 2000)
   690 ----------------------------------
   691 
   692 *** Overview of INCOMPATIBILITIES ***
   693 
   694 * HOL: simplification of natural numbers is much changed; to partly
   695 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   696 issue the following ML commands:
   697 
   698   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   699   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   700 
   701 * HOL: simplification no longer dives into case-expressions; this is
   702 controlled by "t.weak_case_cong" for each datatype t;
   703 
   704 * HOL: nat_less_induct renamed to less_induct;
   705 
   706 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   707 fixsome to patch .thy and .ML sources automatically;
   708 
   709   select_equality  -> some_equality
   710   select_eq_Ex     -> some_eq_ex
   711   selectI2EX       -> someI2_ex
   712   selectI2         -> someI2
   713   selectI          -> someI
   714   select1_equality -> some1_equality
   715   Eps_sym_eq       -> some_sym_eq_trivial
   716   Eps_eq           -> some_eq_trivial
   717 
   718 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   719 
   720 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   721 instead);
   722 
   723 * HOL: the recursion equations generated by 'recdef' are now called
   724 f.simps instead of f.rules;
   725 
   726 * HOL: qed_spec_mp now also handles bounded ALL as well;
   727 
   728 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   729 sometimes be needed;
   730 
   731 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   732 
   733 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   734 
   735 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   736 product is now "<*>" instead of "Times"; the lexicographic product is
   737 now "<*lex*>" instead of "**";
   738 
   739 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   740 of main HOL, but was unused); better use HOL's datatype package;
   741 
   742 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   743 the old syntax may be recovered as follows:
   744 
   745   syntax (symbols)
   746     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   747       (infixl "\\<oplus>" 100)
   748 
   749 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   750 
   751 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   752 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   753 internally;
   754 
   755 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   756 changed from A/r to A//r;
   757 
   758 * ZF: new treatment of arithmetic (nat & int) may break some old
   759 proofs;
   760 
   761 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   762 rulify -> rule_format, elimify -> elim_format, ...);
   763 
   764 * Isar/Provers: intro/elim/dest attributes changed; renamed
   765 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   766 should have to change intro!! to intro? only); replaced "delrule" by
   767 "rule del";
   768 
   769 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   770 
   771 * Provers: strengthened force_tac by using new first_best_tac;
   772 
   773 * LaTeX document preparation: several changes of isabelle.sty (see
   774 lib/texinputs);
   775 
   776 
   777 *** Document preparation ***
   778 
   779 * formal comments (text blocks etc.) in new-style theories may now
   780 contain antiquotations of thm/prop/term/typ/text to be presented
   781 according to latex print mode; concrete syntax is like this:
   782 @{term[show_types] "f(x) = a + x"};
   783 
   784 * isatool mkdir provides easy setup of Isabelle session directories,
   785 including proper document sources;
   786 
   787 * generated LaTeX sources are now deleted after successful run
   788 (isatool document -c); may retain a copy somewhere else via -D option
   789 of isatool usedir;
   790 
   791 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   792 style files, achieving self-contained LaTeX sources and simplifying
   793 LaTeX debugging;
   794 
   795 * old-style theories now produce (crude) LaTeX output as well;
   796 
   797 * browser info session directories are now self-contained (may be put
   798 on WWW server seperately); improved graphs of nested sessions; removed
   799 graph for 'all sessions';
   800 
   801 * several improvements in isabelle style files; \isabellestyle{it}
   802 produces fake math mode output; \isamarkupheader is now \section by
   803 default; see lib/texinputs/isabelle.sty etc.;
   804 
   805 
   806 *** Isar ***
   807 
   808 * Isar/Pure: local results and corresponding term bindings are now
   809 subject to Hindley-Milner polymorphism (similar to ML); this
   810 accommodates incremental type-inference very nicely;
   811 
   812 * Isar/Pure: new derived language element 'obtain' supports
   813 generalized existence reasoning;
   814 
   815 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   816 support accumulation of results, without applying any rules yet;
   817 useful to collect intermediate results without explicit name
   818 references, and for use with transitivity rules with more than 2
   819 premises;
   820 
   821 * Isar/Pure: scalable support for case-analysis type proofs: new
   822 'case' language element refers to local contexts symbolically, as
   823 produced by certain proof methods; internally, case names are attached
   824 to theorems as "tags";
   825 
   826 * Isar/Pure: theory command 'hide' removes declarations from
   827 class/type/const name spaces;
   828 
   829 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   830 indicate potential overloading;
   831 
   832 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   833 
   834 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   835 "{a,b,c}" instead of {a,b,c};
   836 
   837 * Isar/Pure now provides its own version of intro/elim/dest
   838 attributes; useful for building new logics, but beware of confusion
   839 with the version in Provers/classical;
   840 
   841 * Isar/Pure: the local context of (non-atomic) goals is provided via
   842 case name 'antecedent';
   843 
   844 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   845 to the current context is now done automatically);
   846 
   847 * Isar/Pure: theory command 'method_setup' provides a simple interface
   848 for definining proof methods in ML;
   849 
   850 * Isar/Provers: intro/elim/dest attributes changed; renamed
   851 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   852 most cases, one should have to change intro!! to intro? only);
   853 replaced "delrule" by "rule del";
   854 
   855 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   856 'symmetric' attribute (the latter supercedes [RS sym]);
   857 
   858 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   859 method modifier); 'simp' method: 'only:' modifier removes loopers as
   860 well (including splits);
   861 
   862 * Isar/Provers: Simplifier and Classical methods now support all kind
   863 of modifiers used in the past, including 'cong', 'iff', etc.
   864 
   865 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   866 of Simplifier and Classical reasoner);
   867 
   868 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   869 now support named cases; major packages (inductive, datatype, primrec,
   870 recdef) support case names and properly name parameters;
   871 
   872 * Isar/HOL: new transitivity rules for substitution in inequalities --
   873 monotonicity conditions are extracted to be proven at end of
   874 calculations;
   875 
   876 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   877 method anyway;
   878 
   879 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   880 split_if split_if_asm; datatype package provides theorems foo.splits =
   881 foo.split foo.split_asm for each datatype;
   882 
   883 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   884 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   885 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   886 use "(cases (simplified))" method in proper proof texts);
   887 
   888 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   889 
   890 * Isar: names of theorems etc. may be natural numbers as well;
   891 
   892 * Isar: 'pr' command: optional arguments for goals_limit and
   893 ProofContext.prems_limit; no longer prints theory contexts, but only
   894 proof states;
   895 
   896 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   897 additional print modes to be specified; e.g. "pr(latex)" will print
   898 proof state according to the Isabelle LaTeX style;
   899 
   900 * Isar: improved support for emulating tactic scripts, including proof
   901 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   902 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   903 (for HOL datatypes);
   904 
   905 * Isar: simplified (more robust) goal selection of proof methods: 1st
   906 goal, all goals, or explicit goal specifier (tactic emulation); thus
   907 'proof method scripts' have to be in depth-first order;
   908 
   909 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   910 
   911 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   912 should instead use individual commands for printing items
   913 (print_commands, print_methods etc.);
   914 
   915 * Isar: added 'nothing' --- the empty list of theorems;
   916 
   917 
   918 *** HOL ***
   919 
   920 * HOL/MicroJava: formalization of a fragment of Java, together with a
   921 corresponding virtual machine and a specification of its bytecode
   922 verifier and a lightweight bytecode verifier, including proofs of
   923 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   924 Cornelia Pusch (see also the homepage of project Bali at
   925 http://isabelle.in.tum.de/Bali/);
   926 
   927 * HOL/Algebra: new theory of rings and univariate polynomials, by
   928 Clemens Ballarin;
   929 
   930 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   931 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   932 Rasmussen;
   933 
   934 * HOL/Lattice: fundamental concepts of lattice theory and order
   935 structures, including duals, properties of bounds versus algebraic
   936 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   937 Theorem for complete lattices etc.; may also serve as a demonstration
   938 for abstract algebraic reasoning using axiomatic type classes, and
   939 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   940 
   941 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   942 von Oheimb;
   943 
   944 * HOL/IMPP: extension of IMP with local variables and mutually
   945 recursive procedures, by David von Oheimb;
   946 
   947 * HOL/Lambda: converted into new-style theory and document;
   948 
   949 * HOL/ex/Multiquote: example of multiple nested quotations and
   950 anti-quotations -- basically a generalized version of de-Bruijn
   951 representation; very useful in avoiding lifting of operations;
   952 
   953 * HOL/record: added general record equality rule to simpset; fixed
   954 select-update simplification procedure to handle extended records as
   955 well; admit "r" as field name;
   956 
   957 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   958 other numeric types and also as the identity of groups, rings, etc.;
   959 
   960 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   961 Types nat and int belong to this axclass;
   962 
   963 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   964    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   965    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   966   two terms #m*u and #n*u are replaced by #(m+n)*u
   967     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   968   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   969     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   970 
   971 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   972 powerful prover for predicate logic but knows nothing of clasets; see
   973 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   974 
   975 * HOL: new version of "case_tac" subsumes both boolean case split and
   976 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   977 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   978 
   979 * HOL: simplification no longer dives into case-expressions: only the
   980 selector expression is simplified, but not the remaining arms; to
   981 enable full simplification of case-expressions for datatype t, you may
   982 remove t.weak_case_cong from the simpset, either globally (Delcongs
   983 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   984 
   985 * HOL/recdef: the recursion equations generated by 'recdef' for
   986 function 'f' are now called f.simps instead of f.rules; if all
   987 termination conditions are proved automatically, these simplification
   988 rules are added to the simpset, as in primrec; rules may be named
   989 individually as well, resulting in a separate list of theorems for
   990 each equation;
   991 
   992 * HOL/While is a new theory that provides a while-combinator. It
   993 permits the definition of tail-recursive functions without the
   994 provision of a termination measure. The latter is necessary once the
   995 invariant proof rule for while is applied.
   996 
   997 * HOL: new (overloaded) notation for the set of elements below/above
   998 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   999 
  1000 * HOL: theorems impI, allI, ballI bound as "strip";
  1001 
  1002 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1003 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1004 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1005 
  1006 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1007 
  1008 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1009 main HOL, but was unused);
  1010 
  1011 * HOL: fewer consts declared as global (e.g. have to refer to
  1012 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1013 
  1014 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1015 in case of overlap with user translations (e.g. judgements over
  1016 tuples); (note that the underlying logical represenation is still
  1017 bogus);
  1018 
  1019 
  1020 *** ZF ***
  1021 
  1022 * ZF: simplification automatically cancels common terms in arithmetic
  1023 expressions over nat and int;
  1024 
  1025 * ZF: new treatment of nat to minimize type-checking: all operators
  1026 coerce their operands to a natural number using the function natify,
  1027 making the algebraic laws unconditional;
  1028 
  1029 * ZF: as above, for int: operators coerce their operands to an integer
  1030 using the function intify;
  1031 
  1032 * ZF: the integer library now contains many of the usual laws for the
  1033 orderings, including $<=, and monotonicity laws for $+ and $*;
  1034 
  1035 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1036 simplification;
  1037 
  1038 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1039 to the simplifier and classical reasoner simultaneously;
  1040 
  1041 
  1042 *** General ***
  1043 
  1044 * Provers: blast_tac now handles actual object-logic rules as
  1045 assumptions; note that auto_tac uses blast_tac internally as well;
  1046 
  1047 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1048 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1049 
  1050 * Provers: delrules now handles destruct rules as well (no longer need
  1051 explicit make_elim);
  1052 
  1053 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1054   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1055 use instead the strong form,
  1056   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1057 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1058 from destruct-rules;
  1059 
  1060 * Provers: Simplifier.easy_setup provides a fast path to basic
  1061 Simplifier setup for new object-logics;
  1062 
  1063 * Pure: AST translation rules no longer require constant head on LHS;
  1064 
  1065 * Pure: improved name spaces: ambiguous output is qualified; support
  1066 for hiding of names;
  1067 
  1068 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1069 XSYMBOL_HOME; no longer need to do manual configuration in most
  1070 situations;
  1071 
  1072 * system: compression of ML heaps images may now be controlled via -c
  1073 option of isabelle and isatool usedir (currently only observed by
  1074 Poly/ML);
  1075 
  1076 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1077 useful for remote X11);
  1078 
  1079 * system: provide TAGS file for Isabelle sources;
  1080 
  1081 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1082 order;
  1083 
  1084 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1085 timing flag supersedes proof_timing and Toplevel.trace;
  1086 
  1087 * ML: new combinators |>> and |>>> for incremental transformations
  1088 with secondary results (e.g. certain theory extensions):
  1089 
  1090 * ML: PureThy.add_defs gets additional argument to indicate potential
  1091 overloading (usually false);
  1092 
  1093 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1094 results;
  1095 
  1096 
  1097 
  1098 New in Isabelle99 (October 1999)
  1099 --------------------------------
  1100 
  1101 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1102 
  1103 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1104 are no longer simplified.  (This allows the simplifier to unfold recursive
  1105 functional programs.)  To restore the old behaviour, declare
  1106 
  1107     Delcongs [if_weak_cong];
  1108 
  1109 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1110 complement;
  1111 
  1112 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1113 
  1114 * HOL/datatype: mutual_induct_tac no longer exists --
  1115   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1116 
  1117 * HOL/typedef: fixed type inference for representing set; type
  1118 arguments now have to occur explicitly on the rhs as type constraints;
  1119 
  1120 * ZF: The con_defs part of an inductive definition may no longer refer
  1121 to constants declared in the same theory;
  1122 
  1123 * HOL, ZF: the function mk_cases, generated by the inductive
  1124 definition package, has lost an argument.  To simplify its result, it
  1125 uses the default simpset instead of a supplied list of theorems.
  1126 
  1127 * HOL/List: the constructors of type list are now Nil and Cons;
  1128 
  1129 * Simplifier: the type of the infix ML functions
  1130         setSSolver addSSolver setSolver addSolver
  1131 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1132 for packaging solvers. A solver is created via
  1133         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1134 where the string argument is only a comment.
  1135 
  1136 
  1137 *** Proof tools ***
  1138 
  1139 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1140 decision procedure for linear arithmetic. Currently it is used for
  1141 types `nat', `int', and `real' in HOL (see below); it can, should and
  1142 will be instantiated for other types and logics as well.
  1143 
  1144 * The simplifier now accepts rewrite rules with flexible heads, eg
  1145      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1146   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1147   matching.
  1148 
  1149 
  1150 *** General ***
  1151 
  1152 * New Isabelle/Isar subsystem provides an alternative to traditional
  1153 tactical theorem proving; together with the ProofGeneral/isar user
  1154 interface it offers an interactive environment for developing human
  1155 readable proof documents (Isar == Intelligible semi-automated
  1156 reasoning); for further information see isatool doc isar-ref,
  1157 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1158 
  1159 * improved and simplified presentation of theories: better HTML markup
  1160 (including colors), graph views in several sizes; isatool usedir now
  1161 provides a proper interface for user theories (via -P option); actual
  1162 document preparation based on (PDF)LaTeX is available as well (for
  1163 new-style theories only); see isatool doc system for more information;
  1164 
  1165 * native support for Proof General, both for classic Isabelle and
  1166 Isabelle/Isar;
  1167 
  1168 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1169 using the graph browser tool;
  1170 
  1171 * Isabelle manuals now also available as PDF;
  1172 
  1173 * theory loader rewritten from scratch (may not be fully
  1174 bug-compatible); old loadpath variable has been replaced by show_path,
  1175 add_path, del_path, reset_path functions; new operations such as
  1176 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1177 isatool doc ref);
  1178 
  1179 * improved isatool install: option -k creates KDE application icon,
  1180 option -p DIR installs standalone binaries;
  1181 
  1182 * added ML_PLATFORM setting (useful for cross-platform installations);
  1183 more robust handling of platform specific ML images for SML/NJ;
  1184 
  1185 * the settings environment is now statically scoped, i.e. it is never
  1186 created again in sub-processes invoked from isabelle, isatool, or
  1187 Isabelle;
  1188 
  1189 * path element specification '~~' refers to '$ISABELLE_HOME';
  1190 
  1191 * in locales, the "assumes" and "defines" parts may be omitted if
  1192 empty;
  1193 
  1194 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1195 long arrows);
  1196 
  1197 * new print_mode "HTML";
  1198 
  1199 * new flag show_tags controls display of tags of theorems (which are
  1200 basically just comments that may be attached by some tools);
  1201 
  1202 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1203 mode and goal output format:
  1204 
  1205 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1206 244c244
  1207 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1208 ---
  1209 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1210 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1211 181c181
  1212 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1213 ---
  1214 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1215 
  1216 * function bind_thms stores lists of theorems (cf. bind_thm);
  1217 
  1218 * new shorthand tactics ftac, eatac, datac, fatac;
  1219 
  1220 * qed (and friends) now accept "" as result name; in that case the
  1221 theorem is not stored, but proper checks and presentation of the
  1222 result still apply;
  1223 
  1224 * theorem database now also indexes constants "Trueprop", "all",
  1225 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1226 
  1227 
  1228 *** HOL ***
  1229 
  1230 ** HOL arithmetic **
  1231 
  1232 * There are now decision procedures for linear arithmetic over nat and
  1233 int:
  1234 
  1235 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1236 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1237 are treated as atomic; subformulae not involving type `nat' or `int'
  1238 are ignored; quantified subformulae are ignored unless they are
  1239 positive universal or negative existential. The tactic has to be
  1240 invoked by hand and can be a little bit slow. In particular, the
  1241 running time is exponential in the number of occurrences of `min' and
  1242 `max', and `-' on `nat'.
  1243 
  1244 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1245 (negated) (in)equalities among the premises and the conclusion into
  1246 account (i.e. no compound formulae) and does not know about `min' and
  1247 `max', and `-' on `nat'. It is fast and is used automatically by the
  1248 simplifier.
  1249 
  1250 NB: At the moment, these decision procedures do not cope with mixed
  1251 nat/int formulae where the two parts interact, such as `m < n ==>
  1252 int(m) < int(n)'.
  1253 
  1254 * HOL/Numeral provides a generic theory of numerals (encoded
  1255 efficiently as bit strings); setup for types nat/int/real is in place;
  1256 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1257 int, existing theories and proof scripts may require a few additional
  1258 type constraints;
  1259 
  1260 * integer division and remainder can now be performed on constant
  1261 arguments;
  1262 
  1263 * many properties of integer multiplication, division and remainder
  1264 are now available;
  1265 
  1266 * An interface to the Stanford Validity Checker (SVC) is available through the
  1267 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1268 are proved automatically.  SVC must be installed separately, and its results
  1269 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1270 invocation of the underlying oracle).  For SVC see
  1271   http://verify.stanford.edu/SVC
  1272 
  1273 * IsaMakefile: the HOL-Real target now builds an actual image;
  1274 
  1275 
  1276 ** HOL misc **
  1277 
  1278 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1279 (in Isabelle/Isar) -- by Gertrud Bauer;
  1280 
  1281 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1282 analysis for assembly languages with subtypes;
  1283 
  1284 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1285 -- avoids syntactic ambiguities and treats state, transition, and
  1286 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1287 changed syntax and (many) tactics;
  1288 
  1289 * HOL/inductive: Now also handles more general introduction rules such
  1290   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1291   theorems are now maintained within the theory (maintained via the
  1292   "mono" attribute);
  1293 
  1294 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1295   (using function types) such as
  1296 
  1297   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1298 
  1299 * HOL/record: record_simproc (part of the default simpset) takes care
  1300 of selectors applied to updated records; record_split_tac is no longer
  1301 part of the default claset; update_defs may now be removed from the
  1302 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1303 
  1304   claset_ref () := claset() addSWrapper record_split_wrapper;
  1305   Delsimprocs [record_simproc]
  1306 
  1307 * HOL/typedef: fixed type inference for representing set; type
  1308 arguments now have to occur explicitly on the rhs as type constraints;
  1309 
  1310 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1311 names rather than an ML expression;
  1312 
  1313 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1314 supplied later.  Program schemes can be defined, such as
  1315     "While B C s = (if B s then While B C (C s) else s)"
  1316 where the well-founded relation can be chosen after B and C have been given.
  1317 
  1318 * HOL/List: the constructors of type list are now Nil and Cons;
  1319 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1320 course, ML tools referring to List.list.op # etc. have to be adapted;
  1321 
  1322 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1323 disabled by default; run isabelle with option -m HOL to get back to
  1324 the original Gordon/HOL-style output;
  1325 
  1326 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1327 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1328 
  1329 * HOL basic syntax simplified (more orthogonal): all variants of
  1330 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1331 Eps operator is provided as well: "SOME x. P[x]";
  1332 
  1333 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1334 
  1335 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1336 thus available for user theories;
  1337 
  1338 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1339 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1340 time;
  1341 
  1342 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1343 several times and then mp;
  1344 
  1345 
  1346 *** LK ***
  1347 
  1348 * the notation <<...>> is now available as a notation for sequences of
  1349 formulas;
  1350 
  1351 * the simplifier is now installed
  1352 
  1353 * the axiom system has been generalized (thanks to Soren Heilmann)
  1354 
  1355 * the classical reasoner now has a default rule database
  1356 
  1357 
  1358 *** ZF ***
  1359 
  1360 * new primrec section allows primitive recursive functions to be given
  1361 directly (as in HOL) over datatypes and the natural numbers;
  1362 
  1363 * new tactics induct_tac and exhaust_tac for induction (or case
  1364 analysis) over datatypes and the natural numbers;
  1365 
  1366 * the datatype declaration of type T now defines the recursor T_rec;
  1367 
  1368 * simplification automatically does freeness reasoning for datatype
  1369 constructors;
  1370 
  1371 * automatic type-inference, with AddTCs command to insert new
  1372 type-checking rules;
  1373 
  1374 * datatype introduction rules are now added as Safe Introduction rules
  1375 to the claset;
  1376 
  1377 * the syntax "if P then x else y" is now available in addition to
  1378 if(P,x,y);
  1379 
  1380 
  1381 *** Internal programming interfaces ***
  1382 
  1383 * tuned simplifier trace output; new flag debug_simp;
  1384 
  1385 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1386 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1387 
  1388 * AxClass.axclass_tac lost the theory argument;
  1389 
  1390 * tuned current_goals_markers semantics: begin / end goal avoids
  1391 printing empty lines;
  1392 
  1393 * removed prs and prs_fn hook, which was broken because it did not
  1394 include \n in its semantics, forcing writeln to add one
  1395 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1396 string -> unit if you really want to output text without newline;
  1397 
  1398 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1399 plain output, interface builders may have to enable 'isabelle_font'
  1400 mode to get Isabelle font glyphs as before;
  1401 
  1402 * refined token_translation interface; INCOMPATIBILITY: output length
  1403 now of type real instead of int;
  1404 
  1405 * theory loader actions may be traced via new ThyInfo.add_hook
  1406 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1407 your own database of information attached to *whole* theories -- as
  1408 opposed to intra-theory data slots offered via TheoryDataFun;
  1409 
  1410 * proper handling of dangling sort hypotheses (at last!);
  1411 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1412 extra sort hypotheses that can be witnessed from the type signature;
  1413 the force_strip_shyps flag is gone, any remaining shyps are simply
  1414 left in the theorem (with a warning issued by strip_shyps_warning);
  1415 
  1416 
  1417 
  1418 New in Isabelle98-1 (October 1998)
  1419 ----------------------------------
  1420 
  1421 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1422 
  1423 * several changes of automated proof tools;
  1424 
  1425 * HOL: major changes to the inductive and datatype packages, including
  1426 some minor incompatibilities of theory syntax;
  1427 
  1428 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1429 called `inj_on';
  1430 
  1431 * HOL: removed duplicate thms in Arith:
  1432   less_imp_add_less  should be replaced by  trans_less_add1
  1433   le_imp_add_le      should be replaced by  trans_le_add1
  1434 
  1435 * HOL: unary minus is now overloaded (new type constraints may be
  1436 required);
  1437 
  1438 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1439 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1440 now taken as an integer constant.
  1441 
  1442 * Pure: ML function 'theory_of' renamed to 'theory';
  1443 
  1444 
  1445 *** Proof tools ***
  1446 
  1447 * Simplifier:
  1448   1. Asm_full_simp_tac is now more aggressive.
  1449      1. It will sometimes reorient premises if that increases their power to
  1450         simplify.
  1451      2. It does no longer proceed strictly from left to right but may also
  1452         rotate premises to achieve further simplification.
  1453      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1454      old Asm_full_simp_tac in that it does not rotate premises.
  1455   2. The simplifier now knows a little bit about nat-arithmetic.
  1456 
  1457 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1458 allows for selected deletion of wrappers, by introduction of names for
  1459 wrapper functionals.  This implies that addbefore, addSbefore,
  1460 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1461 and that adding two tactics with the same name overwrites the first
  1462 one (emitting a warning).
  1463   type wrapper = (int -> tactic) -> (int -> tactic)
  1464   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1465   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1466   delWrapper, delSWrapper: claset *  string            -> claset
  1467   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1468 
  1469 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1470 semantics; addbefore now affects only the unsafe part of step_tac
  1471 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1472 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1473 by Force_tac;
  1474 
  1475 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1476 compWrapper; added safe wrapper (and access functions for it);
  1477 
  1478 * HOL/split_all_tac is now much faster and fails if there is nothing
  1479 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1480 and the names of the automatically generated variables have changed.
  1481 split_all_tac has moved within claset() from unsafe wrappers to safe
  1482 wrappers, which means that !!-bound variables are split much more
  1483 aggressively, and safe_tac and clarify_tac now split such variables.
  1484 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1485 Note: the same holds for record_split_tac, which does the job of
  1486 split_all_tac for record fields.
  1487 
  1488 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1489 permanently to the default simpset using Addsplits just like
  1490 Addsimps. They can be removed via Delsplits just like
  1491 Delsimps. Lower-case versions are also available.
  1492 
  1493 * HOL/Simplifier: The rule split_if is now part of the default
  1494 simpset. This means that the simplifier will eliminate all occurrences
  1495 of if-then-else in the conclusion of a goal. To prevent this, you can
  1496 either remove split_if completely from the default simpset by
  1497 `Delsplits [split_if]' or remove it in a specific call of the
  1498 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1499 other case splitting rules to/from the default simpset: every datatype
  1500 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1501 t is the name of the datatype).
  1502 
  1503 * Classical reasoner / Simplifier combination: new force_tac (and
  1504 derivatives Force_tac, force) combines rewriting and classical
  1505 reasoning (and whatever other tools) similarly to auto_tac, but is
  1506 aimed to solve the given subgoal completely.
  1507 
  1508 
  1509 *** General ***
  1510 
  1511 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1512 and `goalw': the theory is no longer needed as an explicit argument -
  1513 the current theory context is used; assumptions are no longer returned
  1514 at the ML-level unless one of them starts with ==> or !!; it is
  1515 recommended to convert to these new commands using isatool fixgoal
  1516 (backup your sources first!);
  1517 
  1518 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1519 the current theory context, and 'theory' to lookup stored theories;
  1520 
  1521 * new theory section 'locale' for declaring constants, assumptions and
  1522 definitions that have local scope;
  1523 
  1524 * new theory section 'nonterminals' for purely syntactic types;
  1525 
  1526 * new theory section 'setup' for generic ML setup functions
  1527 (e.g. package initialization);
  1528 
  1529 * the distribution now includes Isabelle icons: see
  1530 lib/logo/isabelle-{small,tiny}.xpm;
  1531 
  1532 * isatool install - install binaries with absolute references to
  1533 ISABELLE_HOME/bin;
  1534 
  1535 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1536 
  1537 * print mode 'emacs' reserved for Isamode;
  1538 
  1539 * support multiple print (ast) translations per constant name;
  1540 
  1541 * theorems involving oracles are now printed with a suffixed [!];
  1542 
  1543 
  1544 *** HOL ***
  1545 
  1546 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1547 
  1548 * HOL/inductive package reorganized and improved: now supports mutual
  1549 definitions such as
  1550 
  1551   inductive EVEN ODD
  1552     intrs
  1553       null "0 : EVEN"
  1554       oddI "n : EVEN ==> Suc n : ODD"
  1555       evenI "n : ODD ==> Suc n : EVEN"
  1556 
  1557 new theorem list "elims" contains an elimination rule for each of the
  1558 recursive sets; inductive definitions now handle disjunctive premises
  1559 correctly (also ZF);
  1560 
  1561 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1562 "mutual_induct" no longer exists - the induction rule is always
  1563 contained in "induct";
  1564 
  1565 
  1566 * HOL/datatype package re-implemented and greatly improved: now
  1567 supports mutually recursive datatypes such as
  1568 
  1569   datatype
  1570     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1571             | SUM ('a aexp) ('a aexp)
  1572             | DIFF ('a aexp) ('a aexp)
  1573             | NUM 'a
  1574   and
  1575     'a bexp = LESS ('a aexp) ('a aexp)
  1576             | AND ('a bexp) ('a bexp)
  1577             | OR ('a bexp) ('a bexp)
  1578 
  1579 as well as indirectly recursive datatypes such as
  1580 
  1581   datatype
  1582     ('a, 'b) term = Var 'a
  1583                   | App 'b ((('a, 'b) term) list)
  1584 
  1585 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1586 induction on mutually / indirectly recursive datatypes.
  1587 
  1588 Primrec equations are now stored in theory and can be accessed via
  1589 <function_name>.simps.
  1590 
  1591 INCOMPATIBILITIES:
  1592 
  1593   - Theories using datatypes must now have theory Datatype as an
  1594     ancestor.
  1595   - The specific <typename>.induct_tac no longer exists - use the
  1596     generic induct_tac instead.
  1597   - natE has been renamed to nat.exhaust - use exhaust_tac
  1598     instead of res_inst_tac ... natE. Note that the variable
  1599     names in nat.exhaust differ from the names in natE, this
  1600     may cause some "fragile" proofs to fail.
  1601   - The theorems split_<typename>_case and split_<typename>_case_asm
  1602     have been renamed to <typename>.split and <typename>.split_asm.
  1603   - Since default sorts of type variables are now handled correctly,
  1604     some datatype definitions may have to be annotated with explicit
  1605     sort constraints.
  1606   - Primrec definitions no longer require function name and type
  1607     of recursive argument.
  1608 
  1609 Consider using isatool fixdatatype to adapt your theories and proof
  1610 scripts to the new package (backup your sources first!).
  1611 
  1612 
  1613 * HOL/record package: considerably improved implementation; now
  1614 includes concrete syntax for record types, terms, updates; theorems
  1615 for surjective pairing and splitting !!-bound record variables; proof
  1616 support is as follows:
  1617 
  1618   1) standard conversions (selectors or updates applied to record
  1619 constructor terms) are part of the standard simpset;
  1620 
  1621   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1622 made part of standard simpset and claset via addIffs;
  1623 
  1624   3) a tactic for record field splitting (record_split_tac) is part of
  1625 the standard claset (addSWrapper);
  1626 
  1627 To get a better idea about these rules you may retrieve them via
  1628 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1629 the name of your record type.
  1630 
  1631 The split tactic 3) conceptually simplifies by the following rule:
  1632 
  1633   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1634 
  1635 Thus any record variable that is bound by meta-all will automatically
  1636 blow up into some record constructor term, consequently the
  1637 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1638 solve record problems automatically.
  1639 
  1640 
  1641 * reorganized the main HOL image: HOL/Integ and String loaded by
  1642 default; theory Main includes everything;
  1643 
  1644 * automatic simplification of integer sums and comparisons, using cancellation;
  1645 
  1646 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1647 
  1648 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1649 
  1650 * many new identities for unions, intersections, set difference, etc.;
  1651 
  1652 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1653 called split_if, split_split, split_sum_case and split_nat_case (to go
  1654 with add/delsplits);
  1655 
  1656 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1657 (?x::unit) = (); this is made part of the default simpset, which COULD
  1658 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1659 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1660 unit_abs_eta_conv is added in order to counter the effect of
  1661 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1662 %u.f();
  1663 
  1664 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1665 makes more sense);
  1666 
  1667 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1668   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1669   disjointness reasoning but breaking a few old proofs.
  1670 
  1671 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1672 to 'converse' from 'inverse' (for compatibility with ZF and some
  1673 literature);
  1674 
  1675 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1676 the well-founded relation;
  1677 
  1678 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1679     Compl A.  The "Compl" syntax remains available as input syntax for this
  1680     release ONLY.
  1681 
  1682 * HOL/Update: new theory of function updates:
  1683     f(a:=b) == %x. if x=a then b else f x
  1684 may also be iterated as in f(a:=b,c:=d,...);
  1685 
  1686 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1687 
  1688 * HOL/List:
  1689   - new function list_update written xs[i:=v] that updates the i-th
  1690     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1691   - new function `upt' written [i..j(] which generates the list
  1692     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1693     bound write [i..j], which is a shorthand for [i..j+1(].
  1694   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1695 
  1696 * HOL/Arith:
  1697   - removed 'pred' (predecessor) function;
  1698   - generalized some theorems about n-1;
  1699   - many new laws about "div" and "mod";
  1700   - new laws about greatest common divisors (see theory ex/Primes);
  1701 
  1702 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1703 instead of "inverse";
  1704 
  1705 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1706   of the multiset ordering;
  1707 
  1708 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1709   (not included by default);
  1710 
  1711 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1712 
  1713 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1714   programs, i.e. different program variables may have different types.
  1715 
  1716 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1717   [previously, this check worked only if the rewrite rule was unconditional]
  1718   Now rew can involve either definitions or equalities (either == or =).
  1719 
  1720 
  1721 *** ZF ***
  1722 
  1723 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1724   only the theorems proved on ZF.ML;
  1725 
  1726 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1727   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1728   disjointness reasoning but breaking a few old proofs.
  1729 
  1730 * ZF/Update: new theory of function updates
  1731     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1732   may also be iterated as in f(a:=b,c:=d,...);
  1733 
  1734 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1735 
  1736 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1737   [previously, this check worked only if the rewrite rule was unconditional]
  1738   Now rew can involve either definitions or equalities (either == or =).
  1739 
  1740 * case_tac provided for compatibility with HOL
  1741     (like the old excluded_middle_tac, but with subgoals swapped)
  1742 
  1743 
  1744 *** Internal programming interfaces ***
  1745 
  1746 * Pure: several new basic modules made available for general use, see
  1747 also src/Pure/README;
  1748 
  1749 * improved the theory data mechanism to support encapsulation (data
  1750 kind name replaced by private Object.kind, acting as authorization
  1751 key); new type-safe user interface via functor TheoryDataFun; generic
  1752 print_data function becomes basically useless;
  1753 
  1754 * removed global_names compatibility flag -- all theory declarations
  1755 are qualified by default;
  1756 
  1757 * module Pure/Syntax now offers quote / antiquote translation
  1758 functions (useful for Hoare logic etc. with implicit dependencies);
  1759 see HOL/ex/Antiquote for an example use;
  1760 
  1761 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1762 cterm -> thm;
  1763 
  1764 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1765 subgoal;
  1766 
  1767 * Display.print_goals function moved to Locale.print_goals;
  1768 
  1769 * standard print function for goals supports current_goals_markers
  1770 variable for marking begin of proof, end of proof, start of goal; the
  1771 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1772 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1773 for example;
  1774 
  1775 
  1776 
  1777 New in Isabelle98 (January 1998)
  1778 --------------------------------
  1779 
  1780 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1781 
  1782 * changed lexical syntax of terms / types: dots made part of long
  1783 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1784 
  1785 * simpset (and claset) reference variable replaced by functions
  1786 simpset / simpset_ref;
  1787 
  1788 * no longer supports theory aliases (via merge) and non-trivial
  1789 implicit merge of thms' signatures;
  1790 
  1791 * most internal names of constants changed due to qualified names;
  1792 
  1793 * changed Pure/Sequence interface (see Pure/seq.ML);
  1794 
  1795 
  1796 *** General Changes ***
  1797 
  1798 * hierachically structured name spaces (for consts, types, axms, thms
  1799 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1800 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1801 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1802 long_names for fully qualified output names; NOTE: ML programs
  1803 (special tactics, packages etc.) referring to internal names may have
  1804 to be adapted to cope with fully qualified names; in case of severe
  1805 backward campatibility problems try setting 'global_names' at compile
  1806 time to have enrything declared within a flat name space; one may also
  1807 fine tune name declarations in theories via the 'global' and 'local'
  1808 section;
  1809 
  1810 * reimplemented the implicit simpset and claset using the new anytype
  1811 data filed in signatures; references simpset:simpset ref etc. are
  1812 replaced by functions simpset:unit->simpset and
  1813 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1814 to patch your ML files accordingly;
  1815 
  1816 * HTML output now includes theory graph data for display with Java
  1817 applet or isatool browser; data generated automatically via isatool
  1818 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1819 
  1820 * defs may now be conditional; improved rewrite_goals_tac to handle
  1821 conditional equations;
  1822 
  1823 * defs now admits additional type arguments, using TYPE('a) syntax;
  1824 
  1825 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1826 creates a new theory node; implicit merge of thms' signatures is
  1827 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1828 transfer:theory->thm->thm in (rare) cases;
  1829 
  1830 * improved handling of draft signatures / theories; draft thms (and
  1831 ctyps, cterms) are automatically promoted to real ones;
  1832 
  1833 * slightly changed interfaces for oracles: admit many per theory, named
  1834 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1835 
  1836 * print_goals: optional output of const types (set show_consts and
  1837 show_types);
  1838 
  1839 * improved output of warnings (###) and errors (***);
  1840 
  1841 * subgoal_tac displays a warning if the new subgoal has type variables;
  1842 
  1843 * removed old README and Makefiles;
  1844 
  1845 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1846 
  1847 * removed obsolete init_pps and init_database;
  1848 
  1849 * deleted the obsolete tactical STATE, which was declared by
  1850     fun STATE tacfun st = tacfun st st;
  1851 
  1852 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1853 (which abbreviates $HOME);
  1854 
  1855 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1856 use isatool fixseq to adapt your ML programs (this works for fully
  1857 qualified references to the Sequence structure only!);
  1858 
  1859 * use_thy no longer requires writable current directory; it always
  1860 reloads .ML *and* .thy file, if either one is out of date;
  1861 
  1862 
  1863 *** Classical Reasoner ***
  1864 
  1865 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1866 tactics that use classical reasoning to simplify a subgoal without
  1867 splitting it into several subgoals;
  1868 
  1869 * Safe_tac: like safe_tac but uses the default claset;
  1870 
  1871 
  1872 *** Simplifier ***
  1873 
  1874 * added simplification meta rules:
  1875     (asm_)(full_)simplify: simpset -> thm -> thm;
  1876 
  1877 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1878 logics (again);
  1879 
  1880 * added prems argument to simplification procedures;
  1881 
  1882 * HOL, FOL, ZF: added infix function `addsplits':
  1883   instead of `<simpset> setloop (split_tac <thms>)'
  1884   you can simply write `<simpset> addsplits <thms>'
  1885 
  1886 
  1887 *** Syntax ***
  1888 
  1889 * TYPE('a) syntax for type reflection terms;
  1890 
  1891 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1892 
  1893 * pretty printer: changed order of mixfix annotation preference (again!);
  1894 
  1895 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1896 
  1897 
  1898 *** HOL ***
  1899 
  1900 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1901   with `addloop' of the simplifier to faciliate case splitting in premises.
  1902 
  1903 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1904 
  1905 * HOL/Auth: new protocol proofs including some for the Internet
  1906   protocol TLS;
  1907 
  1908 * HOL/Map: new theory of `maps' a la VDM;
  1909 
  1910 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1911 cancelling out common nat summands from =, <, <= (in)equalities, or
  1912 differences; simplification procedures nat_cancel_factor for
  1913 cancelling common factor from =, <, <= (in)equalities over natural
  1914 sums; nat_cancel contains both kinds of procedures, it is installed by
  1915 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1916 
  1917 * HOL/simplifier: terms of the form
  1918   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1919   are rewritten to
  1920   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1921   and those of the form
  1922   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1923   are rewritten to
  1924   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1925 
  1926 * HOL/datatype
  1927   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1928 
  1929   P(t_case f1 ... fn x) =
  1930      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1931         ...
  1932        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1933      )
  1934 
  1935   and a theorem `split_t_case_asm' of the form
  1936 
  1937   P(t_case f1 ... fn x) =
  1938     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1939         ...
  1940        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1941      )
  1942   which can be added to a simpset via `addsplits'. The existing theorems
  1943   expand_list_case and expand_option_case have been renamed to
  1944   split_list_case and split_option_case.
  1945 
  1946 * HOL/Arithmetic:
  1947   - `pred n' is automatically converted to `n-1'.
  1948     Users are strongly encouraged not to use `pred' any longer,
  1949     because it will disappear altogether at some point.
  1950   - Users are strongly encouraged to write "0 < n" rather than
  1951     "n ~= 0". Theorems and proof tools have been modified towards this
  1952     `standard'.
  1953 
  1954 * HOL/Lists:
  1955   the function "set_of_list" has been renamed "set" (and its theorems too);
  1956   the function "nth" now takes its arguments in the reverse order and
  1957   has acquired the infix notation "!" as in "xs!n".
  1958 
  1959 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1960 
  1961 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1962   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1963 
  1964 * HOL/record: extensible records with schematic structural subtyping
  1965 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1966 still lacks various theorems and concrete record syntax;
  1967 
  1968 
  1969 *** HOLCF ***
  1970 
  1971 * removed "axioms" and "generated by" sections;
  1972 
  1973 * replaced "ops" section by extended "consts" section, which is capable of
  1974   handling the continuous function space "->" directly;
  1975 
  1976 * domain package:
  1977   . proves theorems immediately and stores them in the theory,
  1978   . creates hierachical name space,
  1979   . now uses normal mixfix annotations (instead of cinfix...),
  1980   . minor changes to some names and values (for consistency),
  1981   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1982   . separator between mutual domain defs: changed "," to "and",
  1983   . improved handling of sort constraints;  now they have to
  1984     appear on the left-hand side of the equations only;
  1985 
  1986 * fixed LAM <x,y,zs>.b syntax;
  1987 
  1988 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1989 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1990 
  1991 
  1992 *** FOL and ZF ***
  1993 
  1994 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1995   with `addloop' of the simplifier to faciliate case splitting in premises.
  1996 
  1997 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1998 in HOL, they strip ALL and --> from proved theorems;
  1999 
  2000 
  2001 
  2002 New in Isabelle94-8 (May 1997)
  2003 ------------------------------
  2004 
  2005 *** General Changes ***
  2006 
  2007 * new utilities to build / run / maintain Isabelle etc. (in parts
  2008 still somewhat experimental); old Makefiles etc. still functional;
  2009 
  2010 * new 'Isabelle System Manual';
  2011 
  2012 * INSTALL text, together with ./configure and ./build scripts;
  2013 
  2014 * reimplemented type inference for greater efficiency, better error
  2015 messages and clean internal interface;
  2016 
  2017 * prlim command for dealing with lots of subgoals (an easier way of
  2018 setting goals_limit);
  2019 
  2020 
  2021 *** Syntax ***
  2022 
  2023 * supports alternative (named) syntax tables (parser and pretty
  2024 printer); internal interface is provided by add_modesyntax(_i);
  2025 
  2026 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2027 be used in conjunction with the Isabelle symbol font; uses the
  2028 "symbols" syntax table;
  2029 
  2030 * added token_translation interface (may translate name tokens in
  2031 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2032 the current print_mode); IMPORTANT: user print translation functions
  2033 are responsible for marking newly introduced bounds
  2034 (Syntax.mark_boundT);
  2035 
  2036 * token translations for modes "xterm" and "xterm_color" that display
  2037 names in bold, underline etc. or colors (which requires a color
  2038 version of xterm);
  2039 
  2040 * infixes may now be declared with names independent of their syntax;
  2041 
  2042 * added typed_print_translation (like print_translation, but may
  2043 access type of constant);
  2044 
  2045 
  2046 *** Classical Reasoner ***
  2047 
  2048 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2049 some limitations.  Blast_tac...
  2050   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2051   + ignores elimination rules that don't have the correct format
  2052         (the conclusion MUST be a formula variable)
  2053   + ignores types, which can make HOL proofs fail
  2054   + rules must not require higher-order unification, e.g. apply_type in ZF
  2055     [message "Function Var's argument not a bound variable" relates to this]
  2056   + its proof strategy is more general but can actually be slower
  2057 
  2058 * substitution with equality assumptions no longer permutes other
  2059 assumptions;
  2060 
  2061 * minor changes in semantics of addafter (now called addaltern); renamed
  2062 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2063 (and access functions for it);
  2064 
  2065 * improved combination of classical reasoner and simplifier:
  2066   + functions for handling clasimpsets
  2067   + improvement of addss: now the simplifier is called _after_ the
  2068     safe steps.
  2069   + safe variant of addss called addSss: uses safe simplifications
  2070     _during_ the safe steps. It is more complete as it allows multiple
  2071     instantiations of unknowns (e.g. with slow_tac).
  2072 
  2073 *** Simplifier ***
  2074 
  2075 * added interface for simplification procedures (functions that
  2076 produce *proven* rewrite rules on the fly, depending on current
  2077 redex);
  2078 
  2079 * ordering on terms as parameter (used for ordered rewriting);
  2080 
  2081 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2082 
  2083 * the solver is now split into a safe and an unsafe part.
  2084 This should be invisible for the normal user, except that the
  2085 functions setsolver and addsolver have been renamed to setSolver and
  2086 addSolver; added safe_asm_full_simp_tac;
  2087 
  2088 
  2089 *** HOL ***
  2090 
  2091 * a generic induction tactic `induct_tac' which works for all datatypes and
  2092 also for type `nat';
  2093 
  2094 * a generic case distinction tactic `exhaust_tac' which works for all
  2095 datatypes and also for type `nat';
  2096 
  2097 * each datatype comes with a function `size';
  2098 
  2099 * patterns in case expressions allow tuple patterns as arguments to
  2100 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2101 
  2102 * primrec now also works with type nat;
  2103 
  2104 * recdef: a new declaration form, allows general recursive functions to be
  2105 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2106 
  2107 * the constant for negation has been renamed from "not" to "Not" to
  2108 harmonize with FOL, ZF, LK, etc.;
  2109 
  2110 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2111 infinite lists;
  2112 
  2113 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2114 
  2115 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2116 problems in commutative rings, using axiomatic type classes for + and *;
  2117 
  2118 * more examples in HOL/MiniML and HOL/Auth;
  2119 
  2120 * more default rewrite rules for quantifiers, union/intersection;
  2121 
  2122 * a new constant `arbitrary == @x.False';
  2123 
  2124 * HOLCF/IOA replaces old HOL/IOA;
  2125 
  2126 * HOLCF changes: derived all rules and arities
  2127   + axiomatic type classes instead of classes
  2128   + typedef instead of faking type definitions
  2129   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2130   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2131   + eliminated the types void, one, tr
  2132   + use unit lift and bool lift (with translations) instead of one and tr
  2133   + eliminated blift from Lift3.thy (use Def instead of blift)
  2134   all eliminated rules are derived as theorems --> no visible changes ;
  2135 
  2136 
  2137 *** ZF ***
  2138 
  2139 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2140 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2141 as ZF_cs addSIs [equalityI];
  2142 
  2143 
  2144 
  2145 New in Isabelle94-7 (November 96)
  2146 ---------------------------------
  2147 
  2148 * allowing negative levels (as offsets) in prlev and choplev;
  2149 
  2150 * super-linear speedup for large simplifications;
  2151 
  2152 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2153 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2154 FAIL); can suppress it using the command Delsimps (ex_simps @
  2155 all_simps); De Morgan laws are also now included, by default;
  2156 
  2157 * improved printing of ==>  :  ~:
  2158 
  2159 * new object-logic "Sequents" adds linear logic, while replacing LK
  2160 and Modal (thanks to Sara Kalvala);
  2161 
  2162 * HOL/Auth: correctness proofs for authentication protocols;
  2163 
  2164 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2165 examples on HOL/Auth);
  2166 
  2167 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2168 the rewriter and classical reasoner simultaneously;
  2169 
  2170 * function uresult no longer returns theorems in "standard" format;
  2171 regain previous version by: val uresult = standard o uresult;
  2172 
  2173 
  2174 
  2175 New in Isabelle94-6
  2176 -------------------
  2177 
  2178 * oracles -- these establish an interface between Isabelle and trusted
  2179 external reasoners, which may deliver results as theorems;
  2180 
  2181 * proof objects (in particular record all uses of oracles);
  2182 
  2183 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2184 
  2185 * "constdefs" section in theory files;
  2186 
  2187 * "primrec" section (HOL) no longer requires names;
  2188 
  2189 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2190 
  2191 
  2192 
  2193 New in Isabelle94-5
  2194 -------------------
  2195 
  2196 * reduced space requirements;
  2197 
  2198 * automatic HTML generation from theories;
  2199 
  2200 * theory files no longer require "..." (quotes) around most types;
  2201 
  2202 * new examples, including two proofs of the Church-Rosser theorem;
  2203 
  2204 * non-curried (1994) version of HOL is no longer distributed;
  2205 
  2206 
  2207 
  2208 New in Isabelle94-4
  2209 -------------------
  2210 
  2211 * greatly reduced space requirements;
  2212 
  2213 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2214 
  2215 * searchable theorem database (see the section "Retrieving theorems" on
  2216 page 8 of the Reference Manual);
  2217 
  2218 * new examples, including Grabczewski's monumental case study of the
  2219 Axiom of Choice;
  2220 
  2221 * The previous version of HOL renamed to Old_HOL;
  2222 
  2223 * The new version of HOL (previously called CHOL) uses a curried syntax
  2224 for functions.  Application looks like f a b instead of f(a,b);
  2225 
  2226 * Mutually recursive inductive definitions finally work in HOL;
  2227 
  2228 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2229 translates to the operator "split";
  2230 
  2231 
  2232 
  2233 New in Isabelle94-3
  2234 -------------------
  2235 
  2236 * new infix operator, addss, allowing the classical reasoner to
  2237 perform simplification at each step of its search.  Example:
  2238         fast_tac (cs addss ss)
  2239 
  2240 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2241 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2242 look like (a,b) instead of <a,b>;
  2243 
  2244 * PLEASE NOTE: CHOL will eventually replace HOL!
  2245 
  2246 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2247 It translates to the operator "split".  A new theory of integers is available;
  2248 
  2249 * In ZF, integer numerals now denote two's-complement binary integers.
  2250 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2251 
  2252 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2253 of the Axiom of Choice;
  2254 
  2255 
  2256 
  2257 New in Isabelle94-2
  2258 -------------------
  2259 
  2260 * Significantly faster resolution;
  2261 
  2262 * the different sections in a .thy file can now be mixed and repeated
  2263 freely;
  2264 
  2265 * Database of theorems for FOL, HOL and ZF.  New
  2266 commands including qed, qed_goal and bind_thm store theorems in the database.
  2267 
  2268 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2269 a given theory (thms_of), or find out what theory a theorem was proved in
  2270 (theory_of_thm);
  2271 
  2272 * Bugs fixed in the inductive definition and datatype packages;
  2273 
  2274 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2275 and HOL_dup_cs obsolete;
  2276 
  2277 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2278 have been removed;
  2279 
  2280 * Simpler definition of function space in ZF;
  2281 
  2282 * new results about cardinal and ordinal arithmetic in ZF;
  2283 
  2284 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2285 types;
  2286 
  2287 
  2288 $Id$