NEWS
author wenzelm
Tue Aug 27 10:59:21 2002 +0200 (2002-08-27)
changeset 13522 934fffeb6f38
parent 13518 a0749ce05100
child 13540 aede0306e214
permissions -rw-r--r--
* Isar: preview of problems to finish 'show' now produce an error
     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 * Provers: improved induct method: assumptions introduced by case
    29 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    30 the goal statement); "foo" still refers to all facts collectively;
    31 
    32 * Isar: preview of problems to finish 'show' now produce an error
    33 rather than just a warning (in interactive mode);
    34 
    35 
    36 *** HOL ***
    37 
    38 * 'typedef' command has new option "open" to suppress the set
    39 definition;
    40 
    41 * functions Min and Max on finite sets have been introduced (theory
    42 Finite_Set);
    43 
    44 * attribute [symmetric] now works for relations as well; it turns
    45 (x,y) : R^-1 into (y,x) : R, and vice versa;
    46 
    47 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    48   In ProofGeneral the counter example appears in the trace buffer.
    49 
    50 * arith(_tac) does now know about div k and mod k where k is a numeral
    51 of type nat or int. It can solve simple goals like
    52 
    53   "0 < n ==> n div 2 < (n::nat)"
    54 
    55 but fails if divisibility plays a role like in
    56 
    57   "n div 2 + (n+1) div 2 = (n::nat)"
    58 
    59 * simp's arithmetic capabilities have been enhanced a bit: it now
    60 takes ~= in premises into account (by performing a case split);
    61 
    62 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands are
    63   distributed over a sum of terms.
    64 
    65 
    66 *** ML ***
    67 
    68 * Pure: Tactic.prove provides sane interface for internal proofs;
    69 omits the infamous "standard" operation, so this is more appropriate
    70 than prove_goalw_cterm in many situations (e.g. in simprocs);
    71 
    72 * Pure: improved error reporting of simprocs;
    73 
    74 * Provers: Simplifier.simproc(_i) provides sane interface for setting
    75 up simprocs;
    76 
    77 
    78 
    79 New in Isabelle2002 (March 2002)
    80 --------------------------------
    81 
    82 *** Document preparation ***
    83 
    84 * greatly simplified document preparation setup, including more
    85 graceful interpretation of isatool usedir -i/-d/-D options, and more
    86 instructive isatool mkdir; users should basically be able to get
    87 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    88 users may run a separate document processing stage manually like this:
    89 "isatool usedir -D output HOL Test && isatool document Test/output";
    90 
    91 * theory dependency graph may now be incorporated into documents;
    92 isatool usedir -g true will produce session_graph.eps/.pdf for use
    93 with \includegraphics of LaTeX;
    94 
    95 * proper spacing of consecutive markup elements, especially text
    96 blocks after section headings;
    97 
    98 * support bold style (for single symbols only), input syntax is like
    99 this: "\<^bold>\<alpha>" or "\<^bold>A";
   100 
   101 * \<bullet> is now output as bold \cdot by default, which looks much
   102 better in printed text;
   103 
   104 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   105 note that these symbols are currently unavailable in Proof General /
   106 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   107 
   108 * isatool latex no longer depends on changed TEXINPUTS, instead
   109 isatool document copies the Isabelle style files to the target
   110 location;
   111 
   112 
   113 *** Isar ***
   114 
   115 * Pure/Provers: improved proof by cases and induction;
   116   - 'case' command admits impromptu naming of parameters (such as
   117     "case (Suc n)");
   118   - 'induct' method divinates rule instantiation from the inductive
   119     claim; no longer requires excessive ?P bindings for proper
   120     instantiation of cases;
   121   - 'induct' method properly enumerates all possibilities of set/type
   122     rules; as a consequence facts may be also passed through *type*
   123     rules without further ado;
   124   - 'induct' method now derives symbolic cases from the *rulified*
   125     rule (before it used to rulify cases stemming from the internal
   126     atomized version); this means that the context of a non-atomic
   127     statement becomes is included in the hypothesis, avoiding the
   128     slightly cumbersome show "PROP ?case" form;
   129   - 'induct' may now use elim-style induction rules without chaining
   130     facts, using ``missing'' premises from the goal state; this allows
   131     rules stemming from inductive sets to be applied in unstructured
   132     scripts, while still benefitting from proper handling of non-atomic
   133     statements; NB: major inductive premises need to be put first, all
   134     the rest of the goal is passed through the induction;
   135   - 'induct' proper support for mutual induction involving non-atomic
   136     rule statements (uses the new concept of simultaneous goals, see
   137     below);
   138   - append all possible rule selections, but only use the first
   139     success (no backtracking);
   140   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   141   - undeclared rule case names default to numbers 1, 2, 3, ...;
   142   - added 'print_induct_rules' (covered by help item in recent Proof
   143     General versions);
   144   - moved induct/cases attributes to Pure, methods to Provers;
   145   - generic method setup instantiated for FOL and HOL;
   146 
   147 * Pure: support multiple simultaneous goal statements, for example
   148 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   149 meta-level mechanism, this acts as if several individual goals had
   150 been stated separately; in particular common proof methods need to be
   151 repeated in order to cover all claims; note that a single elimination
   152 step is *not* sufficient to establish the two conjunctions, so this
   153 fails:
   154 
   155   assume "A & B" then have A and B ..   (*".." fails*)
   156 
   157 better use "obtain" in situations as above; alternative refer to
   158 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   159 
   160 * Pure: proper integration with ``locales''; unlike the original
   161 version by Florian Kammüller, Isar locales package high-level proof
   162 contexts rather than raw logical ones (e.g. we admit to include
   163 attributes everywhere); operations on locales include merge and
   164 rename; support for implicit arguments (``structures''); simultaneous
   165 type-inference over imports and text; see also HOL/ex/Locales.thy for
   166 some examples;
   167 
   168 * Pure: the following commands have been ``localized'', supporting a
   169 target locale specification "(in name)": 'lemma', 'theorem',
   170 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   171 stored both within the locale and at the theory level (exported and
   172 qualified by the locale name);
   173 
   174 * Pure: theory goals may now be specified in ``long'' form, with
   175 ad-hoc contexts consisting of arbitrary locale elements. for example
   176 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   177 definitions may be given, too); the result is a meta-level rule with
   178 the context elements being discharged in the obvious way;
   179 
   180 * Pure: new proof command 'using' allows to augment currently used
   181 facts after a goal statement ('using' is syntactically analogous to
   182 'apply', but acts on the goal's facts only); this allows chained facts
   183 to be separated into parts given before and after a claim, as in
   184 ``from a and b have C using d and e <proof>'';
   185 
   186 * Pure: renamed "antecedent" case to "rule_context";
   187 
   188 * Pure: new 'judgment' command records explicit information about the
   189 object-logic embedding (used by several tools internally); no longer
   190 use hard-wired "Trueprop";
   191 
   192 * Pure: added 'corollary' command;
   193 
   194 * Pure: fixed 'token_translation' command;
   195 
   196 * Pure: removed obsolete 'exported' attribute;
   197 
   198 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   199 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   200 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   201 
   202 * Pure: method 'atomize' presents local goal premises as object-level
   203 statements (atomic meta-level propositions); setup controlled via
   204 rewrite rules declarations of 'atomize' attribute; example
   205 application: 'induct' method with proper rule statements in improper
   206 proof *scripts*;
   207 
   208 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   209 now consider the syntactic context of assumptions, giving a better
   210 chance to get type-inference of the arguments right (this is
   211 especially important for locales);
   212 
   213 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   214 mode;
   215 
   216 * Pure/obtain: the formal conclusion "thesis", being marked as
   217 ``internal'', may no longer be reference directly in the text;
   218 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   219 situations;
   220 
   221 * Pure: generic 'sym' attribute which declares a rule both as pure
   222 'elim?' and for the 'symmetric' operation;
   223 
   224 * Pure: marginal comments ``--'' may now occur just anywhere in the
   225 text; the fixed correlation with particular command syntax has been
   226 discontinued;
   227 
   228 * Pure: new method 'rules' is particularly well-suited for proof
   229 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   230 but often produces more compact proof terms with less detours;
   231 
   232 * Pure/Provers/classical: simplified integration with pure rule
   233 attributes and methods; the classical "intro?/elim?/dest?"
   234 declarations coincide with the pure ones; the "rule" method no longer
   235 includes classically swapped intros; "intro" and "elim" methods no
   236 longer pick rules from the context; also got rid of ML declarations
   237 AddXIs/AddXEs/AddXDs; all of this has some potential for
   238 INCOMPATIBILITY;
   239 
   240 * Provers/classical: attribute 'swapped' produces classical inversions
   241 of introduction rules;
   242 
   243 * Provers/simplifier: 'simplified' attribute may refer to explicit
   244 rules instead of full simplifier context; 'iff' attribute handles
   245 conditional rules;
   246 
   247 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   248 
   249 * HOL: 'recdef' now fails on unfinished automated proofs, use
   250 "(permissive)" option to recover old behavior;
   251 
   252 * HOL: 'inductive' no longer features separate (collective) attributes
   253 for 'intros' (was found too confusing);
   254 
   255 * HOL: properly declared induction rules less_induct and
   256 wf_induct_rule;
   257 
   258 
   259 *** HOL ***
   260 
   261 * HOL: moved over to sane numeral syntax; the new policy is as
   262 follows:
   263 
   264   - 0 and 1 are polymorphic constants, which are defined on any
   265   numeric type (nat, int, real etc.);
   266 
   267   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   268   binary representation internally;
   269 
   270   - type nat has special constructor Suc, and generally prefers Suc 0
   271   over 1::nat and Suc (Suc 0) over 2::nat;
   272 
   273 This change may cause significant problems of INCOMPATIBILITY; here
   274 are some hints on converting existing sources:
   275 
   276   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   277   entities, so expressions involving "-" (unary or binary minus) need
   278   to be spaced properly;
   279 
   280   - existing occurrences of "1" may need to be constraint "1::nat" or
   281   even replaced by Suc 0; similar for old "2";
   282 
   283   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   284 
   285   - remove all special provisions on numerals in proofs;
   286 
   287 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   288 representation (depends on bin_arith_simps in the default context);
   289 
   290 * HOL: symbolic syntax for x^2 (numeral 2);
   291 
   292 * HOL: the class of all HOL types is now called "type" rather than
   293 "term"; INCOMPATIBILITY, need to adapt references to this type class
   294 in axclass/classes, instance/arities, and (usually rare) occurrences
   295 in typings (of consts etc.); internally the class is called
   296 "HOL.type", ML programs should refer to HOLogic.typeS;
   297 
   298 * HOL/record package improvements:
   299   - new derived operations "fields" to build a partial record section,
   300     "extend" to promote a fixed record to a record scheme, and
   301     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   302     declared as simp by default;
   303   - shared operations ("more", "fields", etc.) now need to be always
   304     qualified) --- potential INCOMPATIBILITY;
   305   - removed "make_scheme" operations (use "make" with "extend") --
   306     INCOMPATIBILITY;
   307   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   308   - provides cases/induct rules for use with corresponding Isar
   309     methods (for concrete records, record schemes, concrete more
   310     parts, and schematic more parts -- in that order);
   311   - internal definitions directly based on a light-weight abstract
   312     theory of product types over typedef rather than datatype;
   313 
   314 * HOL: generic code generator for generating executable ML code from
   315 specifications; specific support for HOL constructs such as inductive
   316 datatypes and sets, as well as recursive functions; can be invoked
   317 via 'generate_code' theory section;
   318 
   319 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   320 
   321 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   322 (beware of argument permutation!);
   323 
   324 * HOL: linorder_less_split superseded by linorder_cases;
   325 
   326 * HOL/List: "nodups" renamed to "distinct";
   327 
   328 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   329 to peripheral theory "Hilbert_Choice";
   330 
   331 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   332 in this (rare) case use:
   333 
   334   delSWrapper "split_all_tac"
   335   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   336 
   337 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   338 MAY FAIL;
   339 
   340 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   341 Isabelle's type classes, ^ on functions and relations has too general
   342 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   343 necessary to attach explicit type constraints;
   344 
   345 * HOL/Relation: the prefix name of the infix "O" has been changed from
   346 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   347 renamed accordingly (eg "compI" -> "rel_compI").
   348 
   349 * HOL: syntax translations now work properly with numerals and records
   350 expressions;
   351 
   352 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   353 of "lam" -- INCOMPATIBILITY;
   354 
   355 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   356 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   357 renamed "Product_Type.unit";
   358 
   359 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   360 
   361 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   362 the "cases" method);
   363 
   364 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   365 Florian Kammüller);
   366 
   367 * HOL/IMP: updated and converted to new-style theory format; several
   368 parts turned into readable document, with proper Isar proof texts and
   369 some explanations (by Gerwin Klein);
   370 
   371 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   372 
   373 * HOL-Hyperreal is now a logic image;
   374 
   375 
   376 *** HOLCF ***
   377 
   378 * Isar: consts/constdefs supports mixfix syntax for continuous
   379 operations;
   380 
   381 * Isar: domain package adapted to new-style theory format, e.g. see
   382 HOLCF/ex/Dnat.thy;
   383 
   384 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   385 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   386 lift.induct_tac, always use UU instead of Undef;
   387 
   388 * HOLCF/IMP: updated and converted to new-style theory;
   389 
   390 
   391 *** ZF ***
   392 
   393 * Isar: proper integration of logic-specific tools and packages,
   394 including theory commands '(co)inductive', '(co)datatype',
   395 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   396 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   397 
   398 * theory Main no longer includes AC; for the Axiom of Choice, base
   399 your theory on Main_ZFC;
   400 
   401 * the integer library now covers quotients and remainders, with many
   402 laws relating division to addition, multiplication, etc.;
   403 
   404 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   405 typeless version of the formalism;
   406 
   407 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   408 format;
   409 
   410 * ZF/Induct: new directory for examples of inductive definitions,
   411 including theory Multiset for multiset orderings; converted to
   412 new-style theory format;
   413 
   414 * ZF: many new theorems about lists, ordinals, etc.;
   415 
   416 
   417 *** General ***
   418 
   419 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   420 variable proof controls level of detail: 0 = no proofs (only oracle
   421 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   422 also ref manual for further ML interfaces;
   423 
   424 * Pure/axclass: removed obsolete ML interface
   425 goal_subclass/goal_arity;
   426 
   427 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   428 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   429 separate tokens, so expressions involving minus need to be spaced
   430 properly;
   431 
   432 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   433 rather than "infixl" or "infixr";
   434 
   435 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   436 sort constraint specifications in type inference; e.g. "x::_::foo"
   437 ensures that the type of "x" is of sort "foo" (but not necessarily a
   438 type variable);
   439 
   440 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   441 control output of nested => (types); the default behavior is
   442 "type_brackets";
   443 
   444 * Pure/syntax: builtin parse translation for "_constify" turns valued
   445 tokens into AST constants;
   446 
   447 * Pure/syntax: prefer later declarations of translations and print
   448 translation functions; potential INCOMPATIBILITY: need to reverse
   449 multiple declarations for same syntax element constant;
   450 
   451 * Pure/show_hyps reset by default (in accordance to existing Isar
   452 practice);
   453 
   454 * Provers/classical: renamed addaltern to addafter, addSaltern to
   455 addSafter;
   456 
   457 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   458 as well;
   459 
   460 * system: tested support for MacOS X; should be able to get Isabelle +
   461 Proof General to work in a plain Terminal after installing Poly/ML
   462 (e.g. from the Isabelle distribution area) and GNU bash alone
   463 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   464 support requires further installations, e.g. from
   465 http://fink.sourceforge.net/);
   466 
   467 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   468 
   469 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   470 of 40 MB), cf. ML_OPTIONS;
   471 
   472 * system: Proof General keywords specification is now part of the
   473 Isabelle distribution (see etc/isar-keywords.el);
   474 
   475 * system: support for persistent Proof General sessions (refrain from
   476 outdating all loaded theories on startup); user may create writable
   477 logic images like this: ``isabelle -q HOL Test'';
   478 
   479 * system: smart selection of Isabelle process versus Isabelle
   480 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   481 run both "isabelle" and "Isabelle" even if file names are badly
   482 damaged (executable inspects the case of the first letter of its own
   483 name); added separate "isabelle-process" and "isabelle-interface";
   484 
   485 * system: refrain from any attempt at filtering input streams; no
   486 longer support ``8bit'' encoding of old isabelle font, instead proper
   487 iso-latin characters may now be used; the related isatools
   488 "symbolinput" and "nonascii" have disappeared as well;
   489 
   490 * system: removed old "xterm" interface (the print modes "xterm" and
   491 "xterm_color" are still available for direct use in a suitable
   492 terminal);
   493 
   494 
   495 
   496 New in Isabelle99-2 (February 2001)
   497 -----------------------------------
   498 
   499 *** Overview of INCOMPATIBILITIES ***
   500 
   501 * HOL: please note that theories in the Library and elsewhere often use the
   502 new-style (Isar) format; to refer to their theorems in an ML script you must
   503 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   504 
   505 * HOL: inductive package no longer splits induction rule aggressively,
   506 but only as far as specified by the introductions given; the old
   507 format may be recovered via ML function complete_split_rule or attribute
   508 'split_rule (complete)';
   509 
   510 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   511 gfp_Tarski to gfp_unfold;
   512 
   513 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   514 
   515 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   516 relation); infix "^^" has been renamed "``"; infix "``" has been
   517 renamed "`"; "univalent" has been renamed "single_valued";
   518 
   519 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   520 operation;
   521 
   522 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   523 
   524 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   525 
   526 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   527 consequence, it is no longer monotonic wrt. the local goal context
   528 (which is now passed through the inductive cases);
   529 
   530 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   531 \<gg> to \<ggreater>;
   532 
   533 
   534 *** Document preparation ***
   535 
   536 * \isabellestyle{NAME} selects version of Isabelle output (currently
   537 available: are "it" for near math-mode best-style output, "sl" for
   538 slanted text style, and "tt" for plain type-writer; if no
   539 \isabellestyle command is given, output is according to slanted
   540 type-writer);
   541 
   542 * support sub/super scripts (for single symbols only), input syntax is
   543 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   544 
   545 * some more standard symbols; see Appendix A of the system manual for
   546 the complete list of symbols defined in isabellesym.sty;
   547 
   548 * improved isabelle style files; more abstract symbol implementation
   549 (should now use \isamath{...} and \isatext{...} in custom symbol
   550 definitions);
   551 
   552 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   553 state; Note that presentation of goal states does not conform to
   554 actual human-readable proof documents.  Please do not include goal
   555 states into document output unless you really know what you are doing!
   556 
   557 * proper indentation of antiquoted output with proportional LaTeX
   558 fonts;
   559 
   560 * no_document ML operator temporarily disables LaTeX document
   561 generation;
   562 
   563 * isatool unsymbolize tunes sources for plain ASCII communication;
   564 
   565 
   566 *** Isar ***
   567 
   568 * Pure: Isar now suffers initial goal statements to contain unbound
   569 schematic variables (this does not conform to actual readable proof
   570 documents, due to unpredictable outcome and non-compositional proof
   571 checking); users who know what they are doing may use schematic goals
   572 for Prolog-style synthesis of proven results;
   573 
   574 * Pure: assumption method (an implicit finishing) now handles actual
   575 rules as well;
   576 
   577 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   578 initial goal, declare "that" only as Pure intro (only for single
   579 steps); the "that" rule assumption may now be involved in implicit
   580 finishing, thus ".." becomes a feasible for trivial obtains;
   581 
   582 * Pure: default proof step now includes 'intro_classes'; thus trivial
   583 instance proofs may be performed by "..";
   584 
   585 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   586 statements as well;
   587 
   588 * Pure: more robust selection of calculational rules;
   589 
   590 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   591 rule (as well as the assumption rule);
   592 
   593 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   594 lemmas, using the graph browser tool;
   595 
   596 * Pure: predict failure of "show" in interactive mode;
   597 
   598 * Pure: 'thms_containing' now takes actual terms as arguments;
   599 
   600 * HOL: improved method 'induct' --- now handles non-atomic goals
   601 (potential INCOMPATIBILITY); tuned error handling;
   602 
   603 * HOL: cases and induct rules now provide explicit hints about the
   604 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   605 any remaining facts are inserted into the goal verbatim;
   606 
   607 * HOL: local contexts (aka cases) may now contain term bindings as
   608 well; the 'cases' and 'induct' methods new provide a ?case binding for
   609 the result to be shown in each case;
   610 
   611 * HOL: added 'recdef_tc' command;
   612 
   613 * isatool convert assists in eliminating legacy ML scripts;
   614 
   615 
   616 *** HOL ***
   617 
   618 * HOL/Library: a collection of generic theories to be used together
   619 with main HOL; the theory loader path already includes this directory
   620 by default; the following existing theories have been moved here:
   621 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   622 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   623 
   624 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   625 modelling and verification task performed in Isabelle/HOL +
   626 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   627 
   628 * HOL/Algebra: special summation operator SUM no longer exists, it has
   629 been replaced by setsum; infix 'assoc' now has priority 50 (like
   630 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   631 'domain', this makes the theory consistent with mathematical
   632 literature;
   633 
   634 * HOL basics: added overloaded operations "inverse" and "divide"
   635 (infix "/"), syntax for generic "abs" operation, generic summation
   636 operator \<Sum>;
   637 
   638 * HOL/typedef: simplified package, provide more useful rules (see also
   639 HOL/subset.thy);
   640 
   641 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   642 now expressed as a proper nested rule (old-style tactic scripts may
   643 require atomize_strip_tac to cope with non-atomic premises);
   644 
   645 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   646 to "split_conv" (old name still available for compatibility);
   647 
   648 * HOL: improved concrete syntax for strings (e.g. allows translation
   649 rules with string literals);
   650 
   651 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   652  and Fleuriot's mechanization of analysis, including the transcendental
   653  functions for the reals;
   654 
   655 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   656 
   657 
   658 *** CTT ***
   659 
   660 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   661 "lam" is displayed as TWO lambda-symbols
   662 
   663 * CTT: theory Main now available, containing everything (that is, Bool
   664 and Arith);
   665 
   666 
   667 *** General ***
   668 
   669 * Pure: the Simplifier has been implemented properly as a derived rule
   670 outside of the actual kernel (at last!); the overall performance
   671 penalty in practical applications is about 50%, while reliability of
   672 the Isabelle inference kernel has been greatly improved;
   673 
   674 * print modes "brackets" and "no_brackets" control output of nested =>
   675 (types) and ==> (props); the default behaviour is "brackets";
   676 
   677 * Provers: fast_tac (and friends) now handle actual object-logic rules
   678 as assumptions as well;
   679 
   680 * system: support Poly/ML 4.0;
   681 
   682 * system: isatool install handles KDE version 1 or 2;
   683 
   684 
   685 
   686 New in Isabelle99-1 (October 2000)
   687 ----------------------------------
   688 
   689 *** Overview of INCOMPATIBILITIES ***
   690 
   691 * HOL: simplification of natural numbers is much changed; to partly
   692 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   693 issue the following ML commands:
   694 
   695   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   696   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   697 
   698 * HOL: simplification no longer dives into case-expressions; this is
   699 controlled by "t.weak_case_cong" for each datatype t;
   700 
   701 * HOL: nat_less_induct renamed to less_induct;
   702 
   703 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   704 fixsome to patch .thy and .ML sources automatically;
   705 
   706   select_equality  -> some_equality
   707   select_eq_Ex     -> some_eq_ex
   708   selectI2EX       -> someI2_ex
   709   selectI2         -> someI2
   710   selectI          -> someI
   711   select1_equality -> some1_equality
   712   Eps_sym_eq       -> some_sym_eq_trivial
   713   Eps_eq           -> some_eq_trivial
   714 
   715 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   716 
   717 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   718 instead);
   719 
   720 * HOL: the recursion equations generated by 'recdef' are now called
   721 f.simps instead of f.rules;
   722 
   723 * HOL: qed_spec_mp now also handles bounded ALL as well;
   724 
   725 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   726 sometimes be needed;
   727 
   728 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   729 
   730 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   731 
   732 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   733 product is now "<*>" instead of "Times"; the lexicographic product is
   734 now "<*lex*>" instead of "**";
   735 
   736 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   737 of main HOL, but was unused); better use HOL's datatype package;
   738 
   739 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   740 the old syntax may be recovered as follows:
   741 
   742   syntax (symbols)
   743     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   744       (infixl "\\<oplus>" 100)
   745 
   746 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   747 
   748 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   749 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   750 internally;
   751 
   752 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   753 changed from A/r to A//r;
   754 
   755 * ZF: new treatment of arithmetic (nat & int) may break some old
   756 proofs;
   757 
   758 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   759 rulify -> rule_format, elimify -> elim_format, ...);
   760 
   761 * Isar/Provers: intro/elim/dest attributes changed; renamed
   762 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   763 should have to change intro!! to intro? only); replaced "delrule" by
   764 "rule del";
   765 
   766 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   767 
   768 * Provers: strengthened force_tac by using new first_best_tac;
   769 
   770 * LaTeX document preparation: several changes of isabelle.sty (see
   771 lib/texinputs);
   772 
   773 
   774 *** Document preparation ***
   775 
   776 * formal comments (text blocks etc.) in new-style theories may now
   777 contain antiquotations of thm/prop/term/typ/text to be presented
   778 according to latex print mode; concrete syntax is like this:
   779 @{term[show_types] "f(x) = a + x"};
   780 
   781 * isatool mkdir provides easy setup of Isabelle session directories,
   782 including proper document sources;
   783 
   784 * generated LaTeX sources are now deleted after successful run
   785 (isatool document -c); may retain a copy somewhere else via -D option
   786 of isatool usedir;
   787 
   788 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   789 style files, achieving self-contained LaTeX sources and simplifying
   790 LaTeX debugging;
   791 
   792 * old-style theories now produce (crude) LaTeX output as well;
   793 
   794 * browser info session directories are now self-contained (may be put
   795 on WWW server seperately); improved graphs of nested sessions; removed
   796 graph for 'all sessions';
   797 
   798 * several improvements in isabelle style files; \isabellestyle{it}
   799 produces fake math mode output; \isamarkupheader is now \section by
   800 default; see lib/texinputs/isabelle.sty etc.;
   801 
   802 
   803 *** Isar ***
   804 
   805 * Isar/Pure: local results and corresponding term bindings are now
   806 subject to Hindley-Milner polymorphism (similar to ML); this
   807 accommodates incremental type-inference very nicely;
   808 
   809 * Isar/Pure: new derived language element 'obtain' supports
   810 generalized existence reasoning;
   811 
   812 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   813 support accumulation of results, without applying any rules yet;
   814 useful to collect intermediate results without explicit name
   815 references, and for use with transitivity rules with more than 2
   816 premises;
   817 
   818 * Isar/Pure: scalable support for case-analysis type proofs: new
   819 'case' language element refers to local contexts symbolically, as
   820 produced by certain proof methods; internally, case names are attached
   821 to theorems as "tags";
   822 
   823 * Isar/Pure: theory command 'hide' removes declarations from
   824 class/type/const name spaces;
   825 
   826 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   827 indicate potential overloading;
   828 
   829 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   830 
   831 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   832 "{a,b,c}" instead of {a,b,c};
   833 
   834 * Isar/Pure now provides its own version of intro/elim/dest
   835 attributes; useful for building new logics, but beware of confusion
   836 with the version in Provers/classical;
   837 
   838 * Isar/Pure: the local context of (non-atomic) goals is provided via
   839 case name 'antecedent';
   840 
   841 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   842 to the current context is now done automatically);
   843 
   844 * Isar/Pure: theory command 'method_setup' provides a simple interface
   845 for definining proof methods in ML;
   846 
   847 * Isar/Provers: intro/elim/dest attributes changed; renamed
   848 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   849 most cases, one should have to change intro!! to intro? only);
   850 replaced "delrule" by "rule del";
   851 
   852 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   853 'symmetric' attribute (the latter supercedes [RS sym]);
   854 
   855 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   856 method modifier); 'simp' method: 'only:' modifier removes loopers as
   857 well (including splits);
   858 
   859 * Isar/Provers: Simplifier and Classical methods now support all kind
   860 of modifiers used in the past, including 'cong', 'iff', etc.
   861 
   862 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   863 of Simplifier and Classical reasoner);
   864 
   865 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   866 now support named cases; major packages (inductive, datatype, primrec,
   867 recdef) support case names and properly name parameters;
   868 
   869 * Isar/HOL: new transitivity rules for substitution in inequalities --
   870 monotonicity conditions are extracted to be proven at end of
   871 calculations;
   872 
   873 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   874 method anyway;
   875 
   876 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   877 split_if split_if_asm; datatype package provides theorems foo.splits =
   878 foo.split foo.split_asm for each datatype;
   879 
   880 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   881 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   882 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   883 use "(cases (simplified))" method in proper proof texts);
   884 
   885 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   886 
   887 * Isar: names of theorems etc. may be natural numbers as well;
   888 
   889 * Isar: 'pr' command: optional arguments for goals_limit and
   890 ProofContext.prems_limit; no longer prints theory contexts, but only
   891 proof states;
   892 
   893 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   894 additional print modes to be specified; e.g. "pr(latex)" will print
   895 proof state according to the Isabelle LaTeX style;
   896 
   897 * Isar: improved support for emulating tactic scripts, including proof
   898 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   899 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   900 (for HOL datatypes);
   901 
   902 * Isar: simplified (more robust) goal selection of proof methods: 1st
   903 goal, all goals, or explicit goal specifier (tactic emulation); thus
   904 'proof method scripts' have to be in depth-first order;
   905 
   906 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   907 
   908 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   909 should instead use individual commands for printing items
   910 (print_commands, print_methods etc.);
   911 
   912 * Isar: added 'nothing' --- the empty list of theorems;
   913 
   914 
   915 *** HOL ***
   916 
   917 * HOL/MicroJava: formalization of a fragment of Java, together with a
   918 corresponding virtual machine and a specification of its bytecode
   919 verifier and a lightweight bytecode verifier, including proofs of
   920 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   921 Cornelia Pusch (see also the homepage of project Bali at
   922 http://isabelle.in.tum.de/Bali/);
   923 
   924 * HOL/Algebra: new theory of rings and univariate polynomials, by
   925 Clemens Ballarin;
   926 
   927 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   928 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   929 Rasmussen;
   930 
   931 * HOL/Lattice: fundamental concepts of lattice theory and order
   932 structures, including duals, properties of bounds versus algebraic
   933 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   934 Theorem for complete lattices etc.; may also serve as a demonstration
   935 for abstract algebraic reasoning using axiomatic type classes, and
   936 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   937 
   938 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   939 von Oheimb;
   940 
   941 * HOL/IMPP: extension of IMP with local variables and mutually
   942 recursive procedures, by David von Oheimb;
   943 
   944 * HOL/Lambda: converted into new-style theory and document;
   945 
   946 * HOL/ex/Multiquote: example of multiple nested quotations and
   947 anti-quotations -- basically a generalized version of de-Bruijn
   948 representation; very useful in avoiding lifting of operations;
   949 
   950 * HOL/record: added general record equality rule to simpset; fixed
   951 select-update simplification procedure to handle extended records as
   952 well; admit "r" as field name;
   953 
   954 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   955 other numeric types and also as the identity of groups, rings, etc.;
   956 
   957 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   958 Types nat and int belong to this axclass;
   959 
   960 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   961    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   962    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   963   two terms #m*u and #n*u are replaced by #(m+n)*u
   964     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   965   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   966     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   967 
   968 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   969 powerful prover for predicate logic but knows nothing of clasets; see
   970 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   971 
   972 * HOL: new version of "case_tac" subsumes both boolean case split and
   973 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   974 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   975 
   976 * HOL: simplification no longer dives into case-expressions: only the
   977 selector expression is simplified, but not the remaining arms; to
   978 enable full simplification of case-expressions for datatype t, you may
   979 remove t.weak_case_cong from the simpset, either globally (Delcongs
   980 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   981 
   982 * HOL/recdef: the recursion equations generated by 'recdef' for
   983 function 'f' are now called f.simps instead of f.rules; if all
   984 termination conditions are proved automatically, these simplification
   985 rules are added to the simpset, as in primrec; rules may be named
   986 individually as well, resulting in a separate list of theorems for
   987 each equation;
   988 
   989 * HOL/While is a new theory that provides a while-combinator. It
   990 permits the definition of tail-recursive functions without the
   991 provision of a termination measure. The latter is necessary once the
   992 invariant proof rule for while is applied.
   993 
   994 * HOL: new (overloaded) notation for the set of elements below/above
   995 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   996 
   997 * HOL: theorems impI, allI, ballI bound as "strip";
   998 
   999 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1000 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1001 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1002 
  1003 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1004 
  1005 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1006 main HOL, but was unused);
  1007 
  1008 * HOL: fewer consts declared as global (e.g. have to refer to
  1009 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1010 
  1011 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1012 in case of overlap with user translations (e.g. judgements over
  1013 tuples); (note that the underlying logical represenation is still
  1014 bogus);
  1015 
  1016 
  1017 *** ZF ***
  1018 
  1019 * ZF: simplification automatically cancels common terms in arithmetic
  1020 expressions over nat and int;
  1021 
  1022 * ZF: new treatment of nat to minimize type-checking: all operators
  1023 coerce their operands to a natural number using the function natify,
  1024 making the algebraic laws unconditional;
  1025 
  1026 * ZF: as above, for int: operators coerce their operands to an integer
  1027 using the function intify;
  1028 
  1029 * ZF: the integer library now contains many of the usual laws for the
  1030 orderings, including $<=, and monotonicity laws for $+ and $*;
  1031 
  1032 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1033 simplification;
  1034 
  1035 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1036 to the simplifier and classical reasoner simultaneously;
  1037 
  1038 
  1039 *** General ***
  1040 
  1041 * Provers: blast_tac now handles actual object-logic rules as
  1042 assumptions; note that auto_tac uses blast_tac internally as well;
  1043 
  1044 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1045 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1046 
  1047 * Provers: delrules now handles destruct rules as well (no longer need
  1048 explicit make_elim);
  1049 
  1050 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1051   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1052 use instead the strong form,
  1053   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1054 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1055 from destruct-rules;
  1056 
  1057 * Provers: Simplifier.easy_setup provides a fast path to basic
  1058 Simplifier setup for new object-logics;
  1059 
  1060 * Pure: AST translation rules no longer require constant head on LHS;
  1061 
  1062 * Pure: improved name spaces: ambiguous output is qualified; support
  1063 for hiding of names;
  1064 
  1065 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1066 XSYMBOL_HOME; no longer need to do manual configuration in most
  1067 situations;
  1068 
  1069 * system: compression of ML heaps images may now be controlled via -c
  1070 option of isabelle and isatool usedir (currently only observed by
  1071 Poly/ML);
  1072 
  1073 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1074 useful for remote X11);
  1075 
  1076 * system: provide TAGS file for Isabelle sources;
  1077 
  1078 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1079 order;
  1080 
  1081 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1082 timing flag supersedes proof_timing and Toplevel.trace;
  1083 
  1084 * ML: new combinators |>> and |>>> for incremental transformations
  1085 with secondary results (e.g. certain theory extensions):
  1086 
  1087 * ML: PureThy.add_defs gets additional argument to indicate potential
  1088 overloading (usually false);
  1089 
  1090 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1091 results;
  1092 
  1093 
  1094 
  1095 New in Isabelle99 (October 1999)
  1096 --------------------------------
  1097 
  1098 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1099 
  1100 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1101 are no longer simplified.  (This allows the simplifier to unfold recursive
  1102 functional programs.)  To restore the old behaviour, declare
  1103 
  1104     Delcongs [if_weak_cong];
  1105 
  1106 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1107 complement;
  1108 
  1109 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1110 
  1111 * HOL/datatype: mutual_induct_tac no longer exists --
  1112   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1113 
  1114 * HOL/typedef: fixed type inference for representing set; type
  1115 arguments now have to occur explicitly on the rhs as type constraints;
  1116 
  1117 * ZF: The con_defs part of an inductive definition may no longer refer
  1118 to constants declared in the same theory;
  1119 
  1120 * HOL, ZF: the function mk_cases, generated by the inductive
  1121 definition package, has lost an argument.  To simplify its result, it
  1122 uses the default simpset instead of a supplied list of theorems.
  1123 
  1124 * HOL/List: the constructors of type list are now Nil and Cons;
  1125 
  1126 * Simplifier: the type of the infix ML functions
  1127         setSSolver addSSolver setSolver addSolver
  1128 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1129 for packaging solvers. A solver is created via
  1130         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1131 where the string argument is only a comment.
  1132 
  1133 
  1134 *** Proof tools ***
  1135 
  1136 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1137 decision procedure for linear arithmetic. Currently it is used for
  1138 types `nat', `int', and `real' in HOL (see below); it can, should and
  1139 will be instantiated for other types and logics as well.
  1140 
  1141 * The simplifier now accepts rewrite rules with flexible heads, eg
  1142      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1143   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1144   matching.
  1145 
  1146 
  1147 *** General ***
  1148 
  1149 * New Isabelle/Isar subsystem provides an alternative to traditional
  1150 tactical theorem proving; together with the ProofGeneral/isar user
  1151 interface it offers an interactive environment for developing human
  1152 readable proof documents (Isar == Intelligible semi-automated
  1153 reasoning); for further information see isatool doc isar-ref,
  1154 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1155 
  1156 * improved and simplified presentation of theories: better HTML markup
  1157 (including colors), graph views in several sizes; isatool usedir now
  1158 provides a proper interface for user theories (via -P option); actual
  1159 document preparation based on (PDF)LaTeX is available as well (for
  1160 new-style theories only); see isatool doc system for more information;
  1161 
  1162 * native support for Proof General, both for classic Isabelle and
  1163 Isabelle/Isar;
  1164 
  1165 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1166 using the graph browser tool;
  1167 
  1168 * Isabelle manuals now also available as PDF;
  1169 
  1170 * theory loader rewritten from scratch (may not be fully
  1171 bug-compatible); old loadpath variable has been replaced by show_path,
  1172 add_path, del_path, reset_path functions; new operations such as
  1173 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1174 isatool doc ref);
  1175 
  1176 * improved isatool install: option -k creates KDE application icon,
  1177 option -p DIR installs standalone binaries;
  1178 
  1179 * added ML_PLATFORM setting (useful for cross-platform installations);
  1180 more robust handling of platform specific ML images for SML/NJ;
  1181 
  1182 * the settings environment is now statically scoped, i.e. it is never
  1183 created again in sub-processes invoked from isabelle, isatool, or
  1184 Isabelle;
  1185 
  1186 * path element specification '~~' refers to '$ISABELLE_HOME';
  1187 
  1188 * in locales, the "assumes" and "defines" parts may be omitted if
  1189 empty;
  1190 
  1191 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1192 long arrows);
  1193 
  1194 * new print_mode "HTML";
  1195 
  1196 * new flag show_tags controls display of tags of theorems (which are
  1197 basically just comments that may be attached by some tools);
  1198 
  1199 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1200 mode and goal output format:
  1201 
  1202 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1203 244c244
  1204 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1205 ---
  1206 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1207 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1208 181c181
  1209 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1210 ---
  1211 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1212 
  1213 * function bind_thms stores lists of theorems (cf. bind_thm);
  1214 
  1215 * new shorthand tactics ftac, eatac, datac, fatac;
  1216 
  1217 * qed (and friends) now accept "" as result name; in that case the
  1218 theorem is not stored, but proper checks and presentation of the
  1219 result still apply;
  1220 
  1221 * theorem database now also indexes constants "Trueprop", "all",
  1222 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1223 
  1224 
  1225 *** HOL ***
  1226 
  1227 ** HOL arithmetic **
  1228 
  1229 * There are now decision procedures for linear arithmetic over nat and
  1230 int:
  1231 
  1232 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1233 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1234 are treated as atomic; subformulae not involving type `nat' or `int'
  1235 are ignored; quantified subformulae are ignored unless they are
  1236 positive universal or negative existential. The tactic has to be
  1237 invoked by hand and can be a little bit slow. In particular, the
  1238 running time is exponential in the number of occurrences of `min' and
  1239 `max', and `-' on `nat'.
  1240 
  1241 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1242 (negated) (in)equalities among the premises and the conclusion into
  1243 account (i.e. no compound formulae) and does not know about `min' and
  1244 `max', and `-' on `nat'. It is fast and is used automatically by the
  1245 simplifier.
  1246 
  1247 NB: At the moment, these decision procedures do not cope with mixed
  1248 nat/int formulae where the two parts interact, such as `m < n ==>
  1249 int(m) < int(n)'.
  1250 
  1251 * HOL/Numeral provides a generic theory of numerals (encoded
  1252 efficiently as bit strings); setup for types nat/int/real is in place;
  1253 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1254 int, existing theories and proof scripts may require a few additional
  1255 type constraints;
  1256 
  1257 * integer division and remainder can now be performed on constant
  1258 arguments;
  1259 
  1260 * many properties of integer multiplication, division and remainder
  1261 are now available;
  1262 
  1263 * An interface to the Stanford Validity Checker (SVC) is available through the
  1264 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1265 are proved automatically.  SVC must be installed separately, and its results
  1266 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1267 invocation of the underlying oracle).  For SVC see
  1268   http://verify.stanford.edu/SVC
  1269 
  1270 * IsaMakefile: the HOL-Real target now builds an actual image;
  1271 
  1272 
  1273 ** HOL misc **
  1274 
  1275 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1276 (in Isabelle/Isar) -- by Gertrud Bauer;
  1277 
  1278 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1279 analysis for assembly languages with subtypes;
  1280 
  1281 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1282 -- avoids syntactic ambiguities and treats state, transition, and
  1283 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1284 changed syntax and (many) tactics;
  1285 
  1286 * HOL/inductive: Now also handles more general introduction rules such
  1287   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1288   theorems are now maintained within the theory (maintained via the
  1289   "mono" attribute);
  1290 
  1291 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1292   (using function types) such as
  1293 
  1294   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1295 
  1296 * HOL/record: record_simproc (part of the default simpset) takes care
  1297 of selectors applied to updated records; record_split_tac is no longer
  1298 part of the default claset; update_defs may now be removed from the
  1299 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1300 
  1301   claset_ref () := claset() addSWrapper record_split_wrapper;
  1302   Delsimprocs [record_simproc]
  1303 
  1304 * HOL/typedef: fixed type inference for representing set; type
  1305 arguments now have to occur explicitly on the rhs as type constraints;
  1306 
  1307 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1308 names rather than an ML expression;
  1309 
  1310 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1311 supplied later.  Program schemes can be defined, such as
  1312     "While B C s = (if B s then While B C (C s) else s)"
  1313 where the well-founded relation can be chosen after B and C have been given.
  1314 
  1315 * HOL/List: the constructors of type list are now Nil and Cons;
  1316 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1317 course, ML tools referring to List.list.op # etc. have to be adapted;
  1318 
  1319 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1320 disabled by default; run isabelle with option -m HOL to get back to
  1321 the original Gordon/HOL-style output;
  1322 
  1323 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1324 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1325 
  1326 * HOL basic syntax simplified (more orthogonal): all variants of
  1327 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1328 Eps operator is provided as well: "SOME x. P[x]";
  1329 
  1330 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1331 
  1332 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1333 thus available for user theories;
  1334 
  1335 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1336 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1337 time;
  1338 
  1339 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1340 several times and then mp;
  1341 
  1342 
  1343 *** LK ***
  1344 
  1345 * the notation <<...>> is now available as a notation for sequences of
  1346 formulas;
  1347 
  1348 * the simplifier is now installed
  1349 
  1350 * the axiom system has been generalized (thanks to Soren Heilmann)
  1351 
  1352 * the classical reasoner now has a default rule database
  1353 
  1354 
  1355 *** ZF ***
  1356 
  1357 * new primrec section allows primitive recursive functions to be given
  1358 directly (as in HOL) over datatypes and the natural numbers;
  1359 
  1360 * new tactics induct_tac and exhaust_tac for induction (or case
  1361 analysis) over datatypes and the natural numbers;
  1362 
  1363 * the datatype declaration of type T now defines the recursor T_rec;
  1364 
  1365 * simplification automatically does freeness reasoning for datatype
  1366 constructors;
  1367 
  1368 * automatic type-inference, with AddTCs command to insert new
  1369 type-checking rules;
  1370 
  1371 * datatype introduction rules are now added as Safe Introduction rules
  1372 to the claset;
  1373 
  1374 * the syntax "if P then x else y" is now available in addition to
  1375 if(P,x,y);
  1376 
  1377 
  1378 *** Internal programming interfaces ***
  1379 
  1380 * tuned simplifier trace output; new flag debug_simp;
  1381 
  1382 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1383 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1384 
  1385 * AxClass.axclass_tac lost the theory argument;
  1386 
  1387 * tuned current_goals_markers semantics: begin / end goal avoids
  1388 printing empty lines;
  1389 
  1390 * removed prs and prs_fn hook, which was broken because it did not
  1391 include \n in its semantics, forcing writeln to add one
  1392 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1393 string -> unit if you really want to output text without newline;
  1394 
  1395 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1396 plain output, interface builders may have to enable 'isabelle_font'
  1397 mode to get Isabelle font glyphs as before;
  1398 
  1399 * refined token_translation interface; INCOMPATIBILITY: output length
  1400 now of type real instead of int;
  1401 
  1402 * theory loader actions may be traced via new ThyInfo.add_hook
  1403 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1404 your own database of information attached to *whole* theories -- as
  1405 opposed to intra-theory data slots offered via TheoryDataFun;
  1406 
  1407 * proper handling of dangling sort hypotheses (at last!);
  1408 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1409 extra sort hypotheses that can be witnessed from the type signature;
  1410 the force_strip_shyps flag is gone, any remaining shyps are simply
  1411 left in the theorem (with a warning issued by strip_shyps_warning);
  1412 
  1413 
  1414 
  1415 New in Isabelle98-1 (October 1998)
  1416 ----------------------------------
  1417 
  1418 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1419 
  1420 * several changes of automated proof tools;
  1421 
  1422 * HOL: major changes to the inductive and datatype packages, including
  1423 some minor incompatibilities of theory syntax;
  1424 
  1425 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1426 called `inj_on';
  1427 
  1428 * HOL: removed duplicate thms in Arith:
  1429   less_imp_add_less  should be replaced by  trans_less_add1
  1430   le_imp_add_le      should be replaced by  trans_le_add1
  1431 
  1432 * HOL: unary minus is now overloaded (new type constraints may be
  1433 required);
  1434 
  1435 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1436 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1437 now taken as an integer constant.
  1438 
  1439 * Pure: ML function 'theory_of' renamed to 'theory';
  1440 
  1441 
  1442 *** Proof tools ***
  1443 
  1444 * Simplifier:
  1445   1. Asm_full_simp_tac is now more aggressive.
  1446      1. It will sometimes reorient premises if that increases their power to
  1447         simplify.
  1448      2. It does no longer proceed strictly from left to right but may also
  1449         rotate premises to achieve further simplification.
  1450      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1451      old Asm_full_simp_tac in that it does not rotate premises.
  1452   2. The simplifier now knows a little bit about nat-arithmetic.
  1453 
  1454 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1455 allows for selected deletion of wrappers, by introduction of names for
  1456 wrapper functionals.  This implies that addbefore, addSbefore,
  1457 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1458 and that adding two tactics with the same name overwrites the first
  1459 one (emitting a warning).
  1460   type wrapper = (int -> tactic) -> (int -> tactic)
  1461   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1462   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1463   delWrapper, delSWrapper: claset *  string            -> claset
  1464   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1465 
  1466 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1467 semantics; addbefore now affects only the unsafe part of step_tac
  1468 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1469 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1470 by Force_tac;
  1471 
  1472 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1473 compWrapper; added safe wrapper (and access functions for it);
  1474 
  1475 * HOL/split_all_tac is now much faster and fails if there is nothing
  1476 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1477 and the names of the automatically generated variables have changed.
  1478 split_all_tac has moved within claset() from unsafe wrappers to safe
  1479 wrappers, which means that !!-bound variables are split much more
  1480 aggressively, and safe_tac and clarify_tac now split such variables.
  1481 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1482 Note: the same holds for record_split_tac, which does the job of
  1483 split_all_tac for record fields.
  1484 
  1485 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1486 permanently to the default simpset using Addsplits just like
  1487 Addsimps. They can be removed via Delsplits just like
  1488 Delsimps. Lower-case versions are also available.
  1489 
  1490 * HOL/Simplifier: The rule split_if is now part of the default
  1491 simpset. This means that the simplifier will eliminate all occurrences
  1492 of if-then-else in the conclusion of a goal. To prevent this, you can
  1493 either remove split_if completely from the default simpset by
  1494 `Delsplits [split_if]' or remove it in a specific call of the
  1495 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1496 other case splitting rules to/from the default simpset: every datatype
  1497 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1498 t is the name of the datatype).
  1499 
  1500 * Classical reasoner / Simplifier combination: new force_tac (and
  1501 derivatives Force_tac, force) combines rewriting and classical
  1502 reasoning (and whatever other tools) similarly to auto_tac, but is
  1503 aimed to solve the given subgoal completely.
  1504 
  1505 
  1506 *** General ***
  1507 
  1508 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1509 and `goalw': the theory is no longer needed as an explicit argument -
  1510 the current theory context is used; assumptions are no longer returned
  1511 at the ML-level unless one of them starts with ==> or !!; it is
  1512 recommended to convert to these new commands using isatool fixgoal
  1513 (backup your sources first!);
  1514 
  1515 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1516 the current theory context, and 'theory' to lookup stored theories;
  1517 
  1518 * new theory section 'locale' for declaring constants, assumptions and
  1519 definitions that have local scope;
  1520 
  1521 * new theory section 'nonterminals' for purely syntactic types;
  1522 
  1523 * new theory section 'setup' for generic ML setup functions
  1524 (e.g. package initialization);
  1525 
  1526 * the distribution now includes Isabelle icons: see
  1527 lib/logo/isabelle-{small,tiny}.xpm;
  1528 
  1529 * isatool install - install binaries with absolute references to
  1530 ISABELLE_HOME/bin;
  1531 
  1532 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1533 
  1534 * print mode 'emacs' reserved for Isamode;
  1535 
  1536 * support multiple print (ast) translations per constant name;
  1537 
  1538 * theorems involving oracles are now printed with a suffixed [!];
  1539 
  1540 
  1541 *** HOL ***
  1542 
  1543 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1544 
  1545 * HOL/inductive package reorganized and improved: now supports mutual
  1546 definitions such as
  1547 
  1548   inductive EVEN ODD
  1549     intrs
  1550       null "0 : EVEN"
  1551       oddI "n : EVEN ==> Suc n : ODD"
  1552       evenI "n : ODD ==> Suc n : EVEN"
  1553 
  1554 new theorem list "elims" contains an elimination rule for each of the
  1555 recursive sets; inductive definitions now handle disjunctive premises
  1556 correctly (also ZF);
  1557 
  1558 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1559 "mutual_induct" no longer exists - the induction rule is always
  1560 contained in "induct";
  1561 
  1562 
  1563 * HOL/datatype package re-implemented and greatly improved: now
  1564 supports mutually recursive datatypes such as
  1565 
  1566   datatype
  1567     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1568             | SUM ('a aexp) ('a aexp)
  1569             | DIFF ('a aexp) ('a aexp)
  1570             | NUM 'a
  1571   and
  1572     'a bexp = LESS ('a aexp) ('a aexp)
  1573             | AND ('a bexp) ('a bexp)
  1574             | OR ('a bexp) ('a bexp)
  1575 
  1576 as well as indirectly recursive datatypes such as
  1577 
  1578   datatype
  1579     ('a, 'b) term = Var 'a
  1580                   | App 'b ((('a, 'b) term) list)
  1581 
  1582 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1583 induction on mutually / indirectly recursive datatypes.
  1584 
  1585 Primrec equations are now stored in theory and can be accessed via
  1586 <function_name>.simps.
  1587 
  1588 INCOMPATIBILITIES:
  1589 
  1590   - Theories using datatypes must now have theory Datatype as an
  1591     ancestor.
  1592   - The specific <typename>.induct_tac no longer exists - use the
  1593     generic induct_tac instead.
  1594   - natE has been renamed to nat.exhaust - use exhaust_tac
  1595     instead of res_inst_tac ... natE. Note that the variable
  1596     names in nat.exhaust differ from the names in natE, this
  1597     may cause some "fragile" proofs to fail.
  1598   - The theorems split_<typename>_case and split_<typename>_case_asm
  1599     have been renamed to <typename>.split and <typename>.split_asm.
  1600   - Since default sorts of type variables are now handled correctly,
  1601     some datatype definitions may have to be annotated with explicit
  1602     sort constraints.
  1603   - Primrec definitions no longer require function name and type
  1604     of recursive argument.
  1605 
  1606 Consider using isatool fixdatatype to adapt your theories and proof
  1607 scripts to the new package (backup your sources first!).
  1608 
  1609 
  1610 * HOL/record package: considerably improved implementation; now
  1611 includes concrete syntax for record types, terms, updates; theorems
  1612 for surjective pairing and splitting !!-bound record variables; proof
  1613 support is as follows:
  1614 
  1615   1) standard conversions (selectors or updates applied to record
  1616 constructor terms) are part of the standard simpset;
  1617 
  1618   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1619 made part of standard simpset and claset via addIffs;
  1620 
  1621   3) a tactic for record field splitting (record_split_tac) is part of
  1622 the standard claset (addSWrapper);
  1623 
  1624 To get a better idea about these rules you may retrieve them via
  1625 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1626 the name of your record type.
  1627 
  1628 The split tactic 3) conceptually simplifies by the following rule:
  1629 
  1630   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1631 
  1632 Thus any record variable that is bound by meta-all will automatically
  1633 blow up into some record constructor term, consequently the
  1634 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1635 solve record problems automatically.
  1636 
  1637 
  1638 * reorganized the main HOL image: HOL/Integ and String loaded by
  1639 default; theory Main includes everything;
  1640 
  1641 * automatic simplification of integer sums and comparisons, using cancellation;
  1642 
  1643 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1644 
  1645 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1646 
  1647 * many new identities for unions, intersections, set difference, etc.;
  1648 
  1649 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1650 called split_if, split_split, split_sum_case and split_nat_case (to go
  1651 with add/delsplits);
  1652 
  1653 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1654 (?x::unit) = (); this is made part of the default simpset, which COULD
  1655 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1656 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1657 unit_abs_eta_conv is added in order to counter the effect of
  1658 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1659 %u.f();
  1660 
  1661 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1662 makes more sense);
  1663 
  1664 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1665   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1666   disjointness reasoning but breaking a few old proofs.
  1667 
  1668 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1669 to 'converse' from 'inverse' (for compatibility with ZF and some
  1670 literature);
  1671 
  1672 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1673 the well-founded relation;
  1674 
  1675 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1676     Compl A.  The "Compl" syntax remains available as input syntax for this
  1677     release ONLY.
  1678 
  1679 * HOL/Update: new theory of function updates:
  1680     f(a:=b) == %x. if x=a then b else f x
  1681 may also be iterated as in f(a:=b,c:=d,...);
  1682 
  1683 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1684 
  1685 * HOL/List:
  1686   - new function list_update written xs[i:=v] that updates the i-th
  1687     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1688   - new function `upt' written [i..j(] which generates the list
  1689     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1690     bound write [i..j], which is a shorthand for [i..j+1(].
  1691   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1692 
  1693 * HOL/Arith:
  1694   - removed 'pred' (predecessor) function;
  1695   - generalized some theorems about n-1;
  1696   - many new laws about "div" and "mod";
  1697   - new laws about greatest common divisors (see theory ex/Primes);
  1698 
  1699 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1700 instead of "inverse";
  1701 
  1702 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1703   of the multiset ordering;
  1704 
  1705 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1706   (not included by default);
  1707 
  1708 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1709 
  1710 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1711   programs, i.e. different program variables may have different types.
  1712 
  1713 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1714   [previously, this check worked only if the rewrite rule was unconditional]
  1715   Now rew can involve either definitions or equalities (either == or =).
  1716 
  1717 
  1718 *** ZF ***
  1719 
  1720 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1721   only the theorems proved on ZF.ML;
  1722 
  1723 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1724   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1725   disjointness reasoning but breaking a few old proofs.
  1726 
  1727 * ZF/Update: new theory of function updates
  1728     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1729   may also be iterated as in f(a:=b,c:=d,...);
  1730 
  1731 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1732 
  1733 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1734   [previously, this check worked only if the rewrite rule was unconditional]
  1735   Now rew can involve either definitions or equalities (either == or =).
  1736 
  1737 * case_tac provided for compatibility with HOL
  1738     (like the old excluded_middle_tac, but with subgoals swapped)
  1739 
  1740 
  1741 *** Internal programming interfaces ***
  1742 
  1743 * Pure: several new basic modules made available for general use, see
  1744 also src/Pure/README;
  1745 
  1746 * improved the theory data mechanism to support encapsulation (data
  1747 kind name replaced by private Object.kind, acting as authorization
  1748 key); new type-safe user interface via functor TheoryDataFun; generic
  1749 print_data function becomes basically useless;
  1750 
  1751 * removed global_names compatibility flag -- all theory declarations
  1752 are qualified by default;
  1753 
  1754 * module Pure/Syntax now offers quote / antiquote translation
  1755 functions (useful for Hoare logic etc. with implicit dependencies);
  1756 see HOL/ex/Antiquote for an example use;
  1757 
  1758 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1759 cterm -> thm;
  1760 
  1761 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1762 subgoal;
  1763 
  1764 * Display.print_goals function moved to Locale.print_goals;
  1765 
  1766 * standard print function for goals supports current_goals_markers
  1767 variable for marking begin of proof, end of proof, start of goal; the
  1768 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1769 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1770 for example;
  1771 
  1772 
  1773 
  1774 New in Isabelle98 (January 1998)
  1775 --------------------------------
  1776 
  1777 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1778 
  1779 * changed lexical syntax of terms / types: dots made part of long
  1780 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1781 
  1782 * simpset (and claset) reference variable replaced by functions
  1783 simpset / simpset_ref;
  1784 
  1785 * no longer supports theory aliases (via merge) and non-trivial
  1786 implicit merge of thms' signatures;
  1787 
  1788 * most internal names of constants changed due to qualified names;
  1789 
  1790 * changed Pure/Sequence interface (see Pure/seq.ML);
  1791 
  1792 
  1793 *** General Changes ***
  1794 
  1795 * hierachically structured name spaces (for consts, types, axms, thms
  1796 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1797 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1798 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1799 long_names for fully qualified output names; NOTE: ML programs
  1800 (special tactics, packages etc.) referring to internal names may have
  1801 to be adapted to cope with fully qualified names; in case of severe
  1802 backward campatibility problems try setting 'global_names' at compile
  1803 time to have enrything declared within a flat name space; one may also
  1804 fine tune name declarations in theories via the 'global' and 'local'
  1805 section;
  1806 
  1807 * reimplemented the implicit simpset and claset using the new anytype
  1808 data filed in signatures; references simpset:simpset ref etc. are
  1809 replaced by functions simpset:unit->simpset and
  1810 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1811 to patch your ML files accordingly;
  1812 
  1813 * HTML output now includes theory graph data for display with Java
  1814 applet or isatool browser; data generated automatically via isatool
  1815 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1816 
  1817 * defs may now be conditional; improved rewrite_goals_tac to handle
  1818 conditional equations;
  1819 
  1820 * defs now admits additional type arguments, using TYPE('a) syntax;
  1821 
  1822 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1823 creates a new theory node; implicit merge of thms' signatures is
  1824 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1825 transfer:theory->thm->thm in (rare) cases;
  1826 
  1827 * improved handling of draft signatures / theories; draft thms (and
  1828 ctyps, cterms) are automatically promoted to real ones;
  1829 
  1830 * slightly changed interfaces for oracles: admit many per theory, named
  1831 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1832 
  1833 * print_goals: optional output of const types (set show_consts and
  1834 show_types);
  1835 
  1836 * improved output of warnings (###) and errors (***);
  1837 
  1838 * subgoal_tac displays a warning if the new subgoal has type variables;
  1839 
  1840 * removed old README and Makefiles;
  1841 
  1842 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1843 
  1844 * removed obsolete init_pps and init_database;
  1845 
  1846 * deleted the obsolete tactical STATE, which was declared by
  1847     fun STATE tacfun st = tacfun st st;
  1848 
  1849 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1850 (which abbreviates $HOME);
  1851 
  1852 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1853 use isatool fixseq to adapt your ML programs (this works for fully
  1854 qualified references to the Sequence structure only!);
  1855 
  1856 * use_thy no longer requires writable current directory; it always
  1857 reloads .ML *and* .thy file, if either one is out of date;
  1858 
  1859 
  1860 *** Classical Reasoner ***
  1861 
  1862 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1863 tactics that use classical reasoning to simplify a subgoal without
  1864 splitting it into several subgoals;
  1865 
  1866 * Safe_tac: like safe_tac but uses the default claset;
  1867 
  1868 
  1869 *** Simplifier ***
  1870 
  1871 * added simplification meta rules:
  1872     (asm_)(full_)simplify: simpset -> thm -> thm;
  1873 
  1874 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1875 logics (again);
  1876 
  1877 * added prems argument to simplification procedures;
  1878 
  1879 * HOL, FOL, ZF: added infix function `addsplits':
  1880   instead of `<simpset> setloop (split_tac <thms>)'
  1881   you can simply write `<simpset> addsplits <thms>'
  1882 
  1883 
  1884 *** Syntax ***
  1885 
  1886 * TYPE('a) syntax for type reflection terms;
  1887 
  1888 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1889 
  1890 * pretty printer: changed order of mixfix annotation preference (again!);
  1891 
  1892 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1893 
  1894 
  1895 *** HOL ***
  1896 
  1897 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1898   with `addloop' of the simplifier to faciliate case splitting in premises.
  1899 
  1900 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1901 
  1902 * HOL/Auth: new protocol proofs including some for the Internet
  1903   protocol TLS;
  1904 
  1905 * HOL/Map: new theory of `maps' a la VDM;
  1906 
  1907 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1908 cancelling out common nat summands from =, <, <= (in)equalities, or
  1909 differences; simplification procedures nat_cancel_factor for
  1910 cancelling common factor from =, <, <= (in)equalities over natural
  1911 sums; nat_cancel contains both kinds of procedures, it is installed by
  1912 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1913 
  1914 * HOL/simplifier: terms of the form
  1915   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1916   are rewritten to
  1917   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1918   and those of the form
  1919   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1920   are rewritten to
  1921   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1922 
  1923 * HOL/datatype
  1924   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1925 
  1926   P(t_case f1 ... fn x) =
  1927      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1928         ...
  1929        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1930      )
  1931 
  1932   and a theorem `split_t_case_asm' of the form
  1933 
  1934   P(t_case f1 ... fn x) =
  1935     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1936         ...
  1937        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1938      )
  1939   which can be added to a simpset via `addsplits'. The existing theorems
  1940   expand_list_case and expand_option_case have been renamed to
  1941   split_list_case and split_option_case.
  1942 
  1943 * HOL/Arithmetic:
  1944   - `pred n' is automatically converted to `n-1'.
  1945     Users are strongly encouraged not to use `pred' any longer,
  1946     because it will disappear altogether at some point.
  1947   - Users are strongly encouraged to write "0 < n" rather than
  1948     "n ~= 0". Theorems and proof tools have been modified towards this
  1949     `standard'.
  1950 
  1951 * HOL/Lists:
  1952   the function "set_of_list" has been renamed "set" (and its theorems too);
  1953   the function "nth" now takes its arguments in the reverse order and
  1954   has acquired the infix notation "!" as in "xs!n".
  1955 
  1956 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1957 
  1958 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1959   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1960 
  1961 * HOL/record: extensible records with schematic structural subtyping
  1962 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1963 still lacks various theorems and concrete record syntax;
  1964 
  1965 
  1966 *** HOLCF ***
  1967 
  1968 * removed "axioms" and "generated by" sections;
  1969 
  1970 * replaced "ops" section by extended "consts" section, which is capable of
  1971   handling the continuous function space "->" directly;
  1972 
  1973 * domain package:
  1974   . proves theorems immediately and stores them in the theory,
  1975   . creates hierachical name space,
  1976   . now uses normal mixfix annotations (instead of cinfix...),
  1977   . minor changes to some names and values (for consistency),
  1978   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1979   . separator between mutual domain defs: changed "," to "and",
  1980   . improved handling of sort constraints;  now they have to
  1981     appear on the left-hand side of the equations only;
  1982 
  1983 * fixed LAM <x,y,zs>.b syntax;
  1984 
  1985 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1986 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1987 
  1988 
  1989 *** FOL and ZF ***
  1990 
  1991 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1992   with `addloop' of the simplifier to faciliate case splitting in premises.
  1993 
  1994 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1995 in HOL, they strip ALL and --> from proved theorems;
  1996 
  1997 
  1998 
  1999 New in Isabelle94-8 (May 1997)
  2000 ------------------------------
  2001 
  2002 *** General Changes ***
  2003 
  2004 * new utilities to build / run / maintain Isabelle etc. (in parts
  2005 still somewhat experimental); old Makefiles etc. still functional;
  2006 
  2007 * new 'Isabelle System Manual';
  2008 
  2009 * INSTALL text, together with ./configure and ./build scripts;
  2010 
  2011 * reimplemented type inference for greater efficiency, better error
  2012 messages and clean internal interface;
  2013 
  2014 * prlim command for dealing with lots of subgoals (an easier way of
  2015 setting goals_limit);
  2016 
  2017 
  2018 *** Syntax ***
  2019 
  2020 * supports alternative (named) syntax tables (parser and pretty
  2021 printer); internal interface is provided by add_modesyntax(_i);
  2022 
  2023 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2024 be used in conjunction with the Isabelle symbol font; uses the
  2025 "symbols" syntax table;
  2026 
  2027 * added token_translation interface (may translate name tokens in
  2028 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2029 the current print_mode); IMPORTANT: user print translation functions
  2030 are responsible for marking newly introduced bounds
  2031 (Syntax.mark_boundT);
  2032 
  2033 * token translations for modes "xterm" and "xterm_color" that display
  2034 names in bold, underline etc. or colors (which requires a color
  2035 version of xterm);
  2036 
  2037 * infixes may now be declared with names independent of their syntax;
  2038 
  2039 * added typed_print_translation (like print_translation, but may
  2040 access type of constant);
  2041 
  2042 
  2043 *** Classical Reasoner ***
  2044 
  2045 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2046 some limitations.  Blast_tac...
  2047   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2048   + ignores elimination rules that don't have the correct format
  2049         (the conclusion MUST be a formula variable)
  2050   + ignores types, which can make HOL proofs fail
  2051   + rules must not require higher-order unification, e.g. apply_type in ZF
  2052     [message "Function Var's argument not a bound variable" relates to this]
  2053   + its proof strategy is more general but can actually be slower
  2054 
  2055 * substitution with equality assumptions no longer permutes other
  2056 assumptions;
  2057 
  2058 * minor changes in semantics of addafter (now called addaltern); renamed
  2059 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2060 (and access functions for it);
  2061 
  2062 * improved combination of classical reasoner and simplifier:
  2063   + functions for handling clasimpsets
  2064   + improvement of addss: now the simplifier is called _after_ the
  2065     safe steps.
  2066   + safe variant of addss called addSss: uses safe simplifications
  2067     _during_ the safe steps. It is more complete as it allows multiple
  2068     instantiations of unknowns (e.g. with slow_tac).
  2069 
  2070 *** Simplifier ***
  2071 
  2072 * added interface for simplification procedures (functions that
  2073 produce *proven* rewrite rules on the fly, depending on current
  2074 redex);
  2075 
  2076 * ordering on terms as parameter (used for ordered rewriting);
  2077 
  2078 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2079 
  2080 * the solver is now split into a safe and an unsafe part.
  2081 This should be invisible for the normal user, except that the
  2082 functions setsolver and addsolver have been renamed to setSolver and
  2083 addSolver; added safe_asm_full_simp_tac;
  2084 
  2085 
  2086 *** HOL ***
  2087 
  2088 * a generic induction tactic `induct_tac' which works for all datatypes and
  2089 also for type `nat';
  2090 
  2091 * a generic case distinction tactic `exhaust_tac' which works for all
  2092 datatypes and also for type `nat';
  2093 
  2094 * each datatype comes with a function `size';
  2095 
  2096 * patterns in case expressions allow tuple patterns as arguments to
  2097 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2098 
  2099 * primrec now also works with type nat;
  2100 
  2101 * recdef: a new declaration form, allows general recursive functions to be
  2102 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2103 
  2104 * the constant for negation has been renamed from "not" to "Not" to
  2105 harmonize with FOL, ZF, LK, etc.;
  2106 
  2107 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2108 infinite lists;
  2109 
  2110 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2111 
  2112 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2113 problems in commutative rings, using axiomatic type classes for + and *;
  2114 
  2115 * more examples in HOL/MiniML and HOL/Auth;
  2116 
  2117 * more default rewrite rules for quantifiers, union/intersection;
  2118 
  2119 * a new constant `arbitrary == @x.False';
  2120 
  2121 * HOLCF/IOA replaces old HOL/IOA;
  2122 
  2123 * HOLCF changes: derived all rules and arities
  2124   + axiomatic type classes instead of classes
  2125   + typedef instead of faking type definitions
  2126   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2127   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2128   + eliminated the types void, one, tr
  2129   + use unit lift and bool lift (with translations) instead of one and tr
  2130   + eliminated blift from Lift3.thy (use Def instead of blift)
  2131   all eliminated rules are derived as theorems --> no visible changes ;
  2132 
  2133 
  2134 *** ZF ***
  2135 
  2136 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2137 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2138 as ZF_cs addSIs [equalityI];
  2139 
  2140 
  2141 
  2142 New in Isabelle94-7 (November 96)
  2143 ---------------------------------
  2144 
  2145 * allowing negative levels (as offsets) in prlev and choplev;
  2146 
  2147 * super-linear speedup for large simplifications;
  2148 
  2149 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2150 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2151 FAIL); can suppress it using the command Delsimps (ex_simps @
  2152 all_simps); De Morgan laws are also now included, by default;
  2153 
  2154 * improved printing of ==>  :  ~:
  2155 
  2156 * new object-logic "Sequents" adds linear logic, while replacing LK
  2157 and Modal (thanks to Sara Kalvala);
  2158 
  2159 * HOL/Auth: correctness proofs for authentication protocols;
  2160 
  2161 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2162 examples on HOL/Auth);
  2163 
  2164 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2165 the rewriter and classical reasoner simultaneously;
  2166 
  2167 * function uresult no longer returns theorems in "standard" format;
  2168 regain previous version by: val uresult = standard o uresult;
  2169 
  2170 
  2171 
  2172 New in Isabelle94-6
  2173 -------------------
  2174 
  2175 * oracles -- these establish an interface between Isabelle and trusted
  2176 external reasoners, which may deliver results as theorems;
  2177 
  2178 * proof objects (in particular record all uses of oracles);
  2179 
  2180 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2181 
  2182 * "constdefs" section in theory files;
  2183 
  2184 * "primrec" section (HOL) no longer requires names;
  2185 
  2186 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2187 
  2188 
  2189 
  2190 New in Isabelle94-5
  2191 -------------------
  2192 
  2193 * reduced space requirements;
  2194 
  2195 * automatic HTML generation from theories;
  2196 
  2197 * theory files no longer require "..." (quotes) around most types;
  2198 
  2199 * new examples, including two proofs of the Church-Rosser theorem;
  2200 
  2201 * non-curried (1994) version of HOL is no longer distributed;
  2202 
  2203 
  2204 
  2205 New in Isabelle94-4
  2206 -------------------
  2207 
  2208 * greatly reduced space requirements;
  2209 
  2210 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2211 
  2212 * searchable theorem database (see the section "Retrieving theorems" on
  2213 page 8 of the Reference Manual);
  2214 
  2215 * new examples, including Grabczewski's monumental case study of the
  2216 Axiom of Choice;
  2217 
  2218 * The previous version of HOL renamed to Old_HOL;
  2219 
  2220 * The new version of HOL (previously called CHOL) uses a curried syntax
  2221 for functions.  Application looks like f a b instead of f(a,b);
  2222 
  2223 * Mutually recursive inductive definitions finally work in HOL;
  2224 
  2225 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2226 translates to the operator "split";
  2227 
  2228 
  2229 
  2230 New in Isabelle94-3
  2231 -------------------
  2232 
  2233 * new infix operator, addss, allowing the classical reasoner to
  2234 perform simplification at each step of its search.  Example:
  2235         fast_tac (cs addss ss)
  2236 
  2237 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2238 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2239 look like (a,b) instead of <a,b>;
  2240 
  2241 * PLEASE NOTE: CHOL will eventually replace HOL!
  2242 
  2243 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2244 It translates to the operator "split".  A new theory of integers is available;
  2245 
  2246 * In ZF, integer numerals now denote two's-complement binary integers.
  2247 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2248 
  2249 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2250 of the Axiom of Choice;
  2251 
  2252 
  2253 
  2254 New in Isabelle94-2
  2255 -------------------
  2256 
  2257 * Significantly faster resolution;
  2258 
  2259 * the different sections in a .thy file can now be mixed and repeated
  2260 freely;
  2261 
  2262 * Database of theorems for FOL, HOL and ZF.  New
  2263 commands including qed, qed_goal and bind_thm store theorems in the database.
  2264 
  2265 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2266 a given theory (thms_of), or find out what theory a theorem was proved in
  2267 (theory_of_thm);
  2268 
  2269 * Bugs fixed in the inductive definition and datatype packages;
  2270 
  2271 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2272 and HOL_dup_cs obsolete;
  2273 
  2274 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2275 have been removed;
  2276 
  2277 * Simpler definition of function space in ZF;
  2278 
  2279 * new results about cardinal and ordinal arithmetic in ZF;
  2280 
  2281 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2282 types;
  2283 
  2284 
  2285 $Id$