NEWS
author paulson
Thu Sep 26 10:56:20 2002 +0200 (2002-09-26)
changeset 13587 659813a3f879
parent 13570 0d6a0dce3ba3
child 13613 531f1f524848
permissions -rw-r--r--
GroupTheory and FuncSet
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: locale specifications now produce predicate definitions
    10 according to the body of text (covering assumptions modulo local
    11 definitions); predicate "loc_axioms" covers newly introduced text,
    12 while "loc" is cumulative wrt. all included locale expressions; the
    13 latter view is presented only on export into the global theory
    14 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    15 on the old view without predicates;
    16 
    17 * Pure: predefined locales "var" and "struct" are useful for sharing
    18 parameters (as in CASL, for example); just specify something like
    19 ``var x + var y + struct M'' as import;
    20 
    21 * Pure: improved thms_containing: proper indexing of facts instead of
    22 raw theorems; check validity of results wrt. current name space;
    23 include local facts of proof configuration (also covers active
    24 locales), cover fixed variables in index; may use "_" in term
    25 specification; an optional limit for the number of printed facts may
    26 be given (the default is 40);
    27 
    28 * Pure: disallow duplicate fact bindings within new-style theory files
    29 (batch-mode only);
    30 
    31 * Provers: improved induct method: assumptions introduced by case
    32 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    33 the goal statement); "foo" still refers to all facts collectively;
    34 
    35 * Provers: the function blast.overloaded has been removed: all constants
    36 are regarded as potentially overloaded, which improves robustness in exchange
    37 for slight decrease in efficiency;
    38 
    39 * Isar: preview of problems to finish 'show' now produce an error
    40 rather than just a warning (in interactive mode);
    41 
    42 
    43 *** HOL ***
    44 
    45 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
    46 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
    47 
    48 * 'typedef' command has new option "open" to suppress the set
    49 definition;
    50 
    51 * functions Min and Max on finite sets have been introduced (theory
    52 Finite_Set);
    53 
    54 * attribute [symmetric] now works for relations as well; it turns
    55 (x,y) : R^-1 into (y,x) : R, and vice versa;
    56 
    57 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    58   In ProofGeneral the counter example appears in the trace buffer.
    59 
    60 * arith(_tac) does now know about div k and mod k where k is a numeral
    61 of type nat or int. It can solve simple goals like
    62 
    63   "0 < n ==> n div 2 < (n::nat)"
    64 
    65 but fails if divisibility plays a role like in
    66 
    67   "n div 2 + (n+1) div 2 = (n::nat)"
    68 
    69 * simp's arithmetic capabilities have been enhanced a bit: it now
    70 takes ~= in premises into account (by performing a case split);
    71 
    72 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
    73 are distributed over a sum of terms;
    74 
    75 * the simplifier trace now shows the names of the applied rewrite rules
    76 
    77 * GroupTheory: converted to Isar theories, using locales with implicit structures;
    78 
    79 * Real/HahnBanach: updated and adapted to locales;
    80 
    81 
    82 *** ZF ***
    83 
    84 * ZF/Constructible: consistency proof for AC (Gödel's constructible
    85 universe, etc.);
    86 
    87 * Main ZF: many theories converted to new-style format;
    88 
    89 
    90 *** ML ***
    91 
    92 * Pure: Tactic.prove provides sane interface for internal proofs;
    93 omits the infamous "standard" operation, so this is more appropriate
    94 than prove_goalw_cterm in many situations (e.g. in simprocs);
    95 
    96 * Pure: improved error reporting of simprocs;
    97 
    98 * Provers: Simplifier.simproc(_i) provides sane interface for setting
    99 up simprocs;
   100 
   101 
   102 
   103 New in Isabelle2002 (March 2002)
   104 --------------------------------
   105 
   106 *** Document preparation ***
   107 
   108 * greatly simplified document preparation setup, including more
   109 graceful interpretation of isatool usedir -i/-d/-D options, and more
   110 instructive isatool mkdir; users should basically be able to get
   111 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   112 users may run a separate document processing stage manually like this:
   113 "isatool usedir -D output HOL Test && isatool document Test/output";
   114 
   115 * theory dependency graph may now be incorporated into documents;
   116 isatool usedir -g true will produce session_graph.eps/.pdf for use
   117 with \includegraphics of LaTeX;
   118 
   119 * proper spacing of consecutive markup elements, especially text
   120 blocks after section headings;
   121 
   122 * support bold style (for single symbols only), input syntax is like
   123 this: "\<^bold>\<alpha>" or "\<^bold>A";
   124 
   125 * \<bullet> is now output as bold \cdot by default, which looks much
   126 better in printed text;
   127 
   128 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   129 note that these symbols are currently unavailable in Proof General /
   130 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   131 
   132 * isatool latex no longer depends on changed TEXINPUTS, instead
   133 isatool document copies the Isabelle style files to the target
   134 location;
   135 
   136 
   137 *** Isar ***
   138 
   139 * Pure/Provers: improved proof by cases and induction;
   140   - 'case' command admits impromptu naming of parameters (such as
   141     "case (Suc n)");
   142   - 'induct' method divinates rule instantiation from the inductive
   143     claim; no longer requires excessive ?P bindings for proper
   144     instantiation of cases;
   145   - 'induct' method properly enumerates all possibilities of set/type
   146     rules; as a consequence facts may be also passed through *type*
   147     rules without further ado;
   148   - 'induct' method now derives symbolic cases from the *rulified*
   149     rule (before it used to rulify cases stemming from the internal
   150     atomized version); this means that the context of a non-atomic
   151     statement becomes is included in the hypothesis, avoiding the
   152     slightly cumbersome show "PROP ?case" form;
   153   - 'induct' may now use elim-style induction rules without chaining
   154     facts, using ``missing'' premises from the goal state; this allows
   155     rules stemming from inductive sets to be applied in unstructured
   156     scripts, while still benefitting from proper handling of non-atomic
   157     statements; NB: major inductive premises need to be put first, all
   158     the rest of the goal is passed through the induction;
   159   - 'induct' proper support for mutual induction involving non-atomic
   160     rule statements (uses the new concept of simultaneous goals, see
   161     below);
   162   - append all possible rule selections, but only use the first
   163     success (no backtracking);
   164   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   165   - undeclared rule case names default to numbers 1, 2, 3, ...;
   166   - added 'print_induct_rules' (covered by help item in recent Proof
   167     General versions);
   168   - moved induct/cases attributes to Pure, methods to Provers;
   169   - generic method setup instantiated for FOL and HOL;
   170 
   171 * Pure: support multiple simultaneous goal statements, for example
   172 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   173 meta-level mechanism, this acts as if several individual goals had
   174 been stated separately; in particular common proof methods need to be
   175 repeated in order to cover all claims; note that a single elimination
   176 step is *not* sufficient to establish the two conjunctions, so this
   177 fails:
   178 
   179   assume "A & B" then have A and B ..   (*".." fails*)
   180 
   181 better use "obtain" in situations as above; alternative refer to
   182 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   183 
   184 * Pure: proper integration with ``locales''; unlike the original
   185 version by Florian Kammüller, Isar locales package high-level proof
   186 contexts rather than raw logical ones (e.g. we admit to include
   187 attributes everywhere); operations on locales include merge and
   188 rename; support for implicit arguments (``structures''); simultaneous
   189 type-inference over imports and text; see also HOL/ex/Locales.thy for
   190 some examples;
   191 
   192 * Pure: the following commands have been ``localized'', supporting a
   193 target locale specification "(in name)": 'lemma', 'theorem',
   194 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   195 stored both within the locale and at the theory level (exported and
   196 qualified by the locale name);
   197 
   198 * Pure: theory goals may now be specified in ``long'' form, with
   199 ad-hoc contexts consisting of arbitrary locale elements. for example
   200 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   201 definitions may be given, too); the result is a meta-level rule with
   202 the context elements being discharged in the obvious way;
   203 
   204 * Pure: new proof command 'using' allows to augment currently used
   205 facts after a goal statement ('using' is syntactically analogous to
   206 'apply', but acts on the goal's facts only); this allows chained facts
   207 to be separated into parts given before and after a claim, as in
   208 ``from a and b have C using d and e <proof>'';
   209 
   210 * Pure: renamed "antecedent" case to "rule_context";
   211 
   212 * Pure: new 'judgment' command records explicit information about the
   213 object-logic embedding (used by several tools internally); no longer
   214 use hard-wired "Trueprop";
   215 
   216 * Pure: added 'corollary' command;
   217 
   218 * Pure: fixed 'token_translation' command;
   219 
   220 * Pure: removed obsolete 'exported' attribute;
   221 
   222 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   223 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   224 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   225 
   226 * Pure: method 'atomize' presents local goal premises as object-level
   227 statements (atomic meta-level propositions); setup controlled via
   228 rewrite rules declarations of 'atomize' attribute; example
   229 application: 'induct' method with proper rule statements in improper
   230 proof *scripts*;
   231 
   232 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   233 now consider the syntactic context of assumptions, giving a better
   234 chance to get type-inference of the arguments right (this is
   235 especially important for locales);
   236 
   237 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   238 mode;
   239 
   240 * Pure/obtain: the formal conclusion "thesis", being marked as
   241 ``internal'', may no longer be reference directly in the text;
   242 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   243 situations;
   244 
   245 * Pure: generic 'sym' attribute which declares a rule both as pure
   246 'elim?' and for the 'symmetric' operation;
   247 
   248 * Pure: marginal comments ``--'' may now occur just anywhere in the
   249 text; the fixed correlation with particular command syntax has been
   250 discontinued;
   251 
   252 * Pure: new method 'rules' is particularly well-suited for proof
   253 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   254 but often produces more compact proof terms with less detours;
   255 
   256 * Pure/Provers/classical: simplified integration with pure rule
   257 attributes and methods; the classical "intro?/elim?/dest?"
   258 declarations coincide with the pure ones; the "rule" method no longer
   259 includes classically swapped intros; "intro" and "elim" methods no
   260 longer pick rules from the context; also got rid of ML declarations
   261 AddXIs/AddXEs/AddXDs; all of this has some potential for
   262 INCOMPATIBILITY;
   263 
   264 * Provers/classical: attribute 'swapped' produces classical inversions
   265 of introduction rules;
   266 
   267 * Provers/simplifier: 'simplified' attribute may refer to explicit
   268 rules instead of full simplifier context; 'iff' attribute handles
   269 conditional rules;
   270 
   271 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   272 
   273 * HOL: 'recdef' now fails on unfinished automated proofs, use
   274 "(permissive)" option to recover old behavior;
   275 
   276 * HOL: 'inductive' no longer features separate (collective) attributes
   277 for 'intros' (was found too confusing);
   278 
   279 * HOL: properly declared induction rules less_induct and
   280 wf_induct_rule;
   281 
   282 
   283 *** HOL ***
   284 
   285 * HOL: moved over to sane numeral syntax; the new policy is as
   286 follows:
   287 
   288   - 0 and 1 are polymorphic constants, which are defined on any
   289   numeric type (nat, int, real etc.);
   290 
   291   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   292   binary representation internally;
   293 
   294   - type nat has special constructor Suc, and generally prefers Suc 0
   295   over 1::nat and Suc (Suc 0) over 2::nat;
   296 
   297 This change may cause significant problems of INCOMPATIBILITY; here
   298 are some hints on converting existing sources:
   299 
   300   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   301   entities, so expressions involving "-" (unary or binary minus) need
   302   to be spaced properly;
   303 
   304   - existing occurrences of "1" may need to be constraint "1::nat" or
   305   even replaced by Suc 0; similar for old "2";
   306 
   307   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   308 
   309   - remove all special provisions on numerals in proofs;
   310 
   311 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   312 representation (depends on bin_arith_simps in the default context);
   313 
   314 * HOL: symbolic syntax for x^2 (numeral 2);
   315 
   316 * HOL: the class of all HOL types is now called "type" rather than
   317 "term"; INCOMPATIBILITY, need to adapt references to this type class
   318 in axclass/classes, instance/arities, and (usually rare) occurrences
   319 in typings (of consts etc.); internally the class is called
   320 "HOL.type", ML programs should refer to HOLogic.typeS;
   321 
   322 * HOL/record package improvements:
   323   - new derived operations "fields" to build a partial record section,
   324     "extend" to promote a fixed record to a record scheme, and
   325     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   326     declared as simp by default;
   327   - shared operations ("more", "fields", etc.) now need to be always
   328     qualified) --- potential INCOMPATIBILITY;
   329   - removed "make_scheme" operations (use "make" with "extend") --
   330     INCOMPATIBILITY;
   331   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   332   - provides cases/induct rules for use with corresponding Isar
   333     methods (for concrete records, record schemes, concrete more
   334     parts, and schematic more parts -- in that order);
   335   - internal definitions directly based on a light-weight abstract
   336     theory of product types over typedef rather than datatype;
   337 
   338 * HOL: generic code generator for generating executable ML code from
   339 specifications; specific support for HOL constructs such as inductive
   340 datatypes and sets, as well as recursive functions; can be invoked
   341 via 'generate_code' theory section;
   342 
   343 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   344 
   345 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   346 (beware of argument permutation!);
   347 
   348 * HOL: linorder_less_split superseded by linorder_cases;
   349 
   350 * HOL/List: "nodups" renamed to "distinct";
   351 
   352 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   353 to peripheral theory "Hilbert_Choice";
   354 
   355 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   356 in this (rare) case use:
   357 
   358   delSWrapper "split_all_tac"
   359   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   360 
   361 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   362 MAY FAIL;
   363 
   364 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   365 Isabelle's type classes, ^ on functions and relations has too general
   366 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   367 necessary to attach explicit type constraints;
   368 
   369 * HOL/Relation: the prefix name of the infix "O" has been changed from
   370 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   371 renamed accordingly (eg "compI" -> "rel_compI").
   372 
   373 * HOL: syntax translations now work properly with numerals and records
   374 expressions;
   375 
   376 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   377 of "lam" -- INCOMPATIBILITY;
   378 
   379 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   380 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   381 renamed "Product_Type.unit";
   382 
   383 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   384 
   385 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   386 the "cases" method);
   387 
   388 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   389 Florian Kammüller);
   390 
   391 * HOL/IMP: updated and converted to new-style theory format; several
   392 parts turned into readable document, with proper Isar proof texts and
   393 some explanations (by Gerwin Klein);
   394 
   395 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   396 
   397 * HOL-Hyperreal is now a logic image;
   398 
   399 
   400 *** HOLCF ***
   401 
   402 * Isar: consts/constdefs supports mixfix syntax for continuous
   403 operations;
   404 
   405 * Isar: domain package adapted to new-style theory format, e.g. see
   406 HOLCF/ex/Dnat.thy;
   407 
   408 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   409 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   410 lift.induct_tac, always use UU instead of Undef;
   411 
   412 * HOLCF/IMP: updated and converted to new-style theory;
   413 
   414 
   415 *** ZF ***
   416 
   417 * Isar: proper integration of logic-specific tools and packages,
   418 including theory commands '(co)inductive', '(co)datatype',
   419 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   420 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   421 
   422 * theory Main no longer includes AC; for the Axiom of Choice, base
   423 your theory on Main_ZFC;
   424 
   425 * the integer library now covers quotients and remainders, with many
   426 laws relating division to addition, multiplication, etc.;
   427 
   428 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   429 typeless version of the formalism;
   430 
   431 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   432 format;
   433 
   434 * ZF/Induct: new directory for examples of inductive definitions,
   435 including theory Multiset for multiset orderings; converted to
   436 new-style theory format;
   437 
   438 * ZF: many new theorems about lists, ordinals, etc.;
   439 
   440 
   441 *** General ***
   442 
   443 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   444 variable proof controls level of detail: 0 = no proofs (only oracle
   445 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   446 also ref manual for further ML interfaces;
   447 
   448 * Pure/axclass: removed obsolete ML interface
   449 goal_subclass/goal_arity;
   450 
   451 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   452 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   453 separate tokens, so expressions involving minus need to be spaced
   454 properly;
   455 
   456 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   457 rather than "infixl" or "infixr";
   458 
   459 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   460 sort constraint specifications in type inference; e.g. "x::_::foo"
   461 ensures that the type of "x" is of sort "foo" (but not necessarily a
   462 type variable);
   463 
   464 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   465 control output of nested => (types); the default behavior is
   466 "type_brackets";
   467 
   468 * Pure/syntax: builtin parse translation for "_constify" turns valued
   469 tokens into AST constants;
   470 
   471 * Pure/syntax: prefer later declarations of translations and print
   472 translation functions; potential INCOMPATIBILITY: need to reverse
   473 multiple declarations for same syntax element constant;
   474 
   475 * Pure/show_hyps reset by default (in accordance to existing Isar
   476 practice);
   477 
   478 * Provers/classical: renamed addaltern to addafter, addSaltern to
   479 addSafter;
   480 
   481 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   482 as well;
   483 
   484 * system: tested support for MacOS X; should be able to get Isabelle +
   485 Proof General to work in a plain Terminal after installing Poly/ML
   486 (e.g. from the Isabelle distribution area) and GNU bash alone
   487 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   488 support requires further installations, e.g. from
   489 http://fink.sourceforge.net/);
   490 
   491 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   492 
   493 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   494 of 40 MB), cf. ML_OPTIONS;
   495 
   496 * system: Proof General keywords specification is now part of the
   497 Isabelle distribution (see etc/isar-keywords.el);
   498 
   499 * system: support for persistent Proof General sessions (refrain from
   500 outdating all loaded theories on startup); user may create writable
   501 logic images like this: ``isabelle -q HOL Test'';
   502 
   503 * system: smart selection of Isabelle process versus Isabelle
   504 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   505 run both "isabelle" and "Isabelle" even if file names are badly
   506 damaged (executable inspects the case of the first letter of its own
   507 name); added separate "isabelle-process" and "isabelle-interface";
   508 
   509 * system: refrain from any attempt at filtering input streams; no
   510 longer support ``8bit'' encoding of old isabelle font, instead proper
   511 iso-latin characters may now be used; the related isatools
   512 "symbolinput" and "nonascii" have disappeared as well;
   513 
   514 * system: removed old "xterm" interface (the print modes "xterm" and
   515 "xterm_color" are still available for direct use in a suitable
   516 terminal);
   517 
   518 
   519 
   520 New in Isabelle99-2 (February 2001)
   521 -----------------------------------
   522 
   523 *** Overview of INCOMPATIBILITIES ***
   524 
   525 * HOL: please note that theories in the Library and elsewhere often use the
   526 new-style (Isar) format; to refer to their theorems in an ML script you must
   527 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   528 
   529 * HOL: inductive package no longer splits induction rule aggressively,
   530 but only as far as specified by the introductions given; the old
   531 format may be recovered via ML function complete_split_rule or attribute
   532 'split_rule (complete)';
   533 
   534 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   535 gfp_Tarski to gfp_unfold;
   536 
   537 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   538 
   539 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   540 relation); infix "^^" has been renamed "``"; infix "``" has been
   541 renamed "`"; "univalent" has been renamed "single_valued";
   542 
   543 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   544 operation;
   545 
   546 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   547 
   548 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   549 
   550 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   551 consequence, it is no longer monotonic wrt. the local goal context
   552 (which is now passed through the inductive cases);
   553 
   554 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   555 \<gg> to \<ggreater>;
   556 
   557 
   558 *** Document preparation ***
   559 
   560 * \isabellestyle{NAME} selects version of Isabelle output (currently
   561 available: are "it" for near math-mode best-style output, "sl" for
   562 slanted text style, and "tt" for plain type-writer; if no
   563 \isabellestyle command is given, output is according to slanted
   564 type-writer);
   565 
   566 * support sub/super scripts (for single symbols only), input syntax is
   567 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   568 
   569 * some more standard symbols; see Appendix A of the system manual for
   570 the complete list of symbols defined in isabellesym.sty;
   571 
   572 * improved isabelle style files; more abstract symbol implementation
   573 (should now use \isamath{...} and \isatext{...} in custom symbol
   574 definitions);
   575 
   576 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   577 state; Note that presentation of goal states does not conform to
   578 actual human-readable proof documents.  Please do not include goal
   579 states into document output unless you really know what you are doing!
   580 
   581 * proper indentation of antiquoted output with proportional LaTeX
   582 fonts;
   583 
   584 * no_document ML operator temporarily disables LaTeX document
   585 generation;
   586 
   587 * isatool unsymbolize tunes sources for plain ASCII communication;
   588 
   589 
   590 *** Isar ***
   591 
   592 * Pure: Isar now suffers initial goal statements to contain unbound
   593 schematic variables (this does not conform to actual readable proof
   594 documents, due to unpredictable outcome and non-compositional proof
   595 checking); users who know what they are doing may use schematic goals
   596 for Prolog-style synthesis of proven results;
   597 
   598 * Pure: assumption method (an implicit finishing) now handles actual
   599 rules as well;
   600 
   601 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   602 initial goal, declare "that" only as Pure intro (only for single
   603 steps); the "that" rule assumption may now be involved in implicit
   604 finishing, thus ".." becomes a feasible for trivial obtains;
   605 
   606 * Pure: default proof step now includes 'intro_classes'; thus trivial
   607 instance proofs may be performed by "..";
   608 
   609 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   610 statements as well;
   611 
   612 * Pure: more robust selection of calculational rules;
   613 
   614 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   615 rule (as well as the assumption rule);
   616 
   617 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   618 lemmas, using the graph browser tool;
   619 
   620 * Pure: predict failure of "show" in interactive mode;
   621 
   622 * Pure: 'thms_containing' now takes actual terms as arguments;
   623 
   624 * HOL: improved method 'induct' --- now handles non-atomic goals
   625 (potential INCOMPATIBILITY); tuned error handling;
   626 
   627 * HOL: cases and induct rules now provide explicit hints about the
   628 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   629 any remaining facts are inserted into the goal verbatim;
   630 
   631 * HOL: local contexts (aka cases) may now contain term bindings as
   632 well; the 'cases' and 'induct' methods new provide a ?case binding for
   633 the result to be shown in each case;
   634 
   635 * HOL: added 'recdef_tc' command;
   636 
   637 * isatool convert assists in eliminating legacy ML scripts;
   638 
   639 
   640 *** HOL ***
   641 
   642 * HOL/Library: a collection of generic theories to be used together
   643 with main HOL; the theory loader path already includes this directory
   644 by default; the following existing theories have been moved here:
   645 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   646 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   647 
   648 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   649 modelling and verification task performed in Isabelle/HOL +
   650 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   651 
   652 * HOL/Algebra: special summation operator SUM no longer exists, it has
   653 been replaced by setsum; infix 'assoc' now has priority 50 (like
   654 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   655 'domain', this makes the theory consistent with mathematical
   656 literature;
   657 
   658 * HOL basics: added overloaded operations "inverse" and "divide"
   659 (infix "/"), syntax for generic "abs" operation, generic summation
   660 operator \<Sum>;
   661 
   662 * HOL/typedef: simplified package, provide more useful rules (see also
   663 HOL/subset.thy);
   664 
   665 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   666 now expressed as a proper nested rule (old-style tactic scripts may
   667 require atomize_strip_tac to cope with non-atomic premises);
   668 
   669 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   670 to "split_conv" (old name still available for compatibility);
   671 
   672 * HOL: improved concrete syntax for strings (e.g. allows translation
   673 rules with string literals);
   674 
   675 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   676  and Fleuriot's mechanization of analysis, including the transcendental
   677  functions for the reals;
   678 
   679 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   680 
   681 
   682 *** CTT ***
   683 
   684 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   685 "lam" is displayed as TWO lambda-symbols
   686 
   687 * CTT: theory Main now available, containing everything (that is, Bool
   688 and Arith);
   689 
   690 
   691 *** General ***
   692 
   693 * Pure: the Simplifier has been implemented properly as a derived rule
   694 outside of the actual kernel (at last!); the overall performance
   695 penalty in practical applications is about 50%, while reliability of
   696 the Isabelle inference kernel has been greatly improved;
   697 
   698 * print modes "brackets" and "no_brackets" control output of nested =>
   699 (types) and ==> (props); the default behaviour is "brackets";
   700 
   701 * Provers: fast_tac (and friends) now handle actual object-logic rules
   702 as assumptions as well;
   703 
   704 * system: support Poly/ML 4.0;
   705 
   706 * system: isatool install handles KDE version 1 or 2;
   707 
   708 
   709 
   710 New in Isabelle99-1 (October 2000)
   711 ----------------------------------
   712 
   713 *** Overview of INCOMPATIBILITIES ***
   714 
   715 * HOL: simplification of natural numbers is much changed; to partly
   716 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   717 issue the following ML commands:
   718 
   719   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   720   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   721 
   722 * HOL: simplification no longer dives into case-expressions; this is
   723 controlled by "t.weak_case_cong" for each datatype t;
   724 
   725 * HOL: nat_less_induct renamed to less_induct;
   726 
   727 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   728 fixsome to patch .thy and .ML sources automatically;
   729 
   730   select_equality  -> some_equality
   731   select_eq_Ex     -> some_eq_ex
   732   selectI2EX       -> someI2_ex
   733   selectI2         -> someI2
   734   selectI          -> someI
   735   select1_equality -> some1_equality
   736   Eps_sym_eq       -> some_sym_eq_trivial
   737   Eps_eq           -> some_eq_trivial
   738 
   739 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   740 
   741 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   742 instead);
   743 
   744 * HOL: the recursion equations generated by 'recdef' are now called
   745 f.simps instead of f.rules;
   746 
   747 * HOL: qed_spec_mp now also handles bounded ALL as well;
   748 
   749 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   750 sometimes be needed;
   751 
   752 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   753 
   754 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   755 
   756 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   757 product is now "<*>" instead of "Times"; the lexicographic product is
   758 now "<*lex*>" instead of "**";
   759 
   760 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   761 of main HOL, but was unused); better use HOL's datatype package;
   762 
   763 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   764 the old syntax may be recovered as follows:
   765 
   766   syntax (symbols)
   767     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   768       (infixl "\\<oplus>" 100)
   769 
   770 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   771 
   772 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   773 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   774 internally;
   775 
   776 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   777 changed from A/r to A//r;
   778 
   779 * ZF: new treatment of arithmetic (nat & int) may break some old
   780 proofs;
   781 
   782 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   783 rulify -> rule_format, elimify -> elim_format, ...);
   784 
   785 * Isar/Provers: intro/elim/dest attributes changed; renamed
   786 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   787 should have to change intro!! to intro? only); replaced "delrule" by
   788 "rule del";
   789 
   790 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   791 
   792 * Provers: strengthened force_tac by using new first_best_tac;
   793 
   794 * LaTeX document preparation: several changes of isabelle.sty (see
   795 lib/texinputs);
   796 
   797 
   798 *** Document preparation ***
   799 
   800 * formal comments (text blocks etc.) in new-style theories may now
   801 contain antiquotations of thm/prop/term/typ/text to be presented
   802 according to latex print mode; concrete syntax is like this:
   803 @{term[show_types] "f(x) = a + x"};
   804 
   805 * isatool mkdir provides easy setup of Isabelle session directories,
   806 including proper document sources;
   807 
   808 * generated LaTeX sources are now deleted after successful run
   809 (isatool document -c); may retain a copy somewhere else via -D option
   810 of isatool usedir;
   811 
   812 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   813 style files, achieving self-contained LaTeX sources and simplifying
   814 LaTeX debugging;
   815 
   816 * old-style theories now produce (crude) LaTeX output as well;
   817 
   818 * browser info session directories are now self-contained (may be put
   819 on WWW server seperately); improved graphs of nested sessions; removed
   820 graph for 'all sessions';
   821 
   822 * several improvements in isabelle style files; \isabellestyle{it}
   823 produces fake math mode output; \isamarkupheader is now \section by
   824 default; see lib/texinputs/isabelle.sty etc.;
   825 
   826 
   827 *** Isar ***
   828 
   829 * Isar/Pure: local results and corresponding term bindings are now
   830 subject to Hindley-Milner polymorphism (similar to ML); this
   831 accommodates incremental type-inference very nicely;
   832 
   833 * Isar/Pure: new derived language element 'obtain' supports
   834 generalized existence reasoning;
   835 
   836 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   837 support accumulation of results, without applying any rules yet;
   838 useful to collect intermediate results without explicit name
   839 references, and for use with transitivity rules with more than 2
   840 premises;
   841 
   842 * Isar/Pure: scalable support for case-analysis type proofs: new
   843 'case' language element refers to local contexts symbolically, as
   844 produced by certain proof methods; internally, case names are attached
   845 to theorems as "tags";
   846 
   847 * Isar/Pure: theory command 'hide' removes declarations from
   848 class/type/const name spaces;
   849 
   850 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   851 indicate potential overloading;
   852 
   853 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   854 
   855 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   856 "{a,b,c}" instead of {a,b,c};
   857 
   858 * Isar/Pure now provides its own version of intro/elim/dest
   859 attributes; useful for building new logics, but beware of confusion
   860 with the version in Provers/classical;
   861 
   862 * Isar/Pure: the local context of (non-atomic) goals is provided via
   863 case name 'antecedent';
   864 
   865 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   866 to the current context is now done automatically);
   867 
   868 * Isar/Pure: theory command 'method_setup' provides a simple interface
   869 for definining proof methods in ML;
   870 
   871 * Isar/Provers: intro/elim/dest attributes changed; renamed
   872 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   873 most cases, one should have to change intro!! to intro? only);
   874 replaced "delrule" by "rule del";
   875 
   876 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   877 'symmetric' attribute (the latter supercedes [RS sym]);
   878 
   879 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   880 method modifier); 'simp' method: 'only:' modifier removes loopers as
   881 well (including splits);
   882 
   883 * Isar/Provers: Simplifier and Classical methods now support all kind
   884 of modifiers used in the past, including 'cong', 'iff', etc.
   885 
   886 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   887 of Simplifier and Classical reasoner);
   888 
   889 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   890 now support named cases; major packages (inductive, datatype, primrec,
   891 recdef) support case names and properly name parameters;
   892 
   893 * Isar/HOL: new transitivity rules for substitution in inequalities --
   894 monotonicity conditions are extracted to be proven at end of
   895 calculations;
   896 
   897 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   898 method anyway;
   899 
   900 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   901 split_if split_if_asm; datatype package provides theorems foo.splits =
   902 foo.split foo.split_asm for each datatype;
   903 
   904 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   905 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   906 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   907 use "(cases (simplified))" method in proper proof texts);
   908 
   909 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   910 
   911 * Isar: names of theorems etc. may be natural numbers as well;
   912 
   913 * Isar: 'pr' command: optional arguments for goals_limit and
   914 ProofContext.prems_limit; no longer prints theory contexts, but only
   915 proof states;
   916 
   917 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   918 additional print modes to be specified; e.g. "pr(latex)" will print
   919 proof state according to the Isabelle LaTeX style;
   920 
   921 * Isar: improved support for emulating tactic scripts, including proof
   922 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   923 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   924 (for HOL datatypes);
   925 
   926 * Isar: simplified (more robust) goal selection of proof methods: 1st
   927 goal, all goals, or explicit goal specifier (tactic emulation); thus
   928 'proof method scripts' have to be in depth-first order;
   929 
   930 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   931 
   932 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   933 should instead use individual commands for printing items
   934 (print_commands, print_methods etc.);
   935 
   936 * Isar: added 'nothing' --- the empty list of theorems;
   937 
   938 
   939 *** HOL ***
   940 
   941 * HOL/MicroJava: formalization of a fragment of Java, together with a
   942 corresponding virtual machine and a specification of its bytecode
   943 verifier and a lightweight bytecode verifier, including proofs of
   944 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   945 Cornelia Pusch (see also the homepage of project Bali at
   946 http://isabelle.in.tum.de/Bali/);
   947 
   948 * HOL/Algebra: new theory of rings and univariate polynomials, by
   949 Clemens Ballarin;
   950 
   951 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   952 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   953 Rasmussen;
   954 
   955 * HOL/Lattice: fundamental concepts of lattice theory and order
   956 structures, including duals, properties of bounds versus algebraic
   957 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   958 Theorem for complete lattices etc.; may also serve as a demonstration
   959 for abstract algebraic reasoning using axiomatic type classes, and
   960 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   961 
   962 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   963 von Oheimb;
   964 
   965 * HOL/IMPP: extension of IMP with local variables and mutually
   966 recursive procedures, by David von Oheimb;
   967 
   968 * HOL/Lambda: converted into new-style theory and document;
   969 
   970 * HOL/ex/Multiquote: example of multiple nested quotations and
   971 anti-quotations -- basically a generalized version of de-Bruijn
   972 representation; very useful in avoiding lifting of operations;
   973 
   974 * HOL/record: added general record equality rule to simpset; fixed
   975 select-update simplification procedure to handle extended records as
   976 well; admit "r" as field name;
   977 
   978 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   979 other numeric types and also as the identity of groups, rings, etc.;
   980 
   981 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   982 Types nat and int belong to this axclass;
   983 
   984 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   985    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   986    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   987   two terms #m*u and #n*u are replaced by #(m+n)*u
   988     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   989   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   990     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   991 
   992 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   993 powerful prover for predicate logic but knows nothing of clasets; see
   994 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   995 
   996 * HOL: new version of "case_tac" subsumes both boolean case split and
   997 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   998 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   999 
  1000 * HOL: simplification no longer dives into case-expressions: only the
  1001 selector expression is simplified, but not the remaining arms; to
  1002 enable full simplification of case-expressions for datatype t, you may
  1003 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1004 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1005 
  1006 * HOL/recdef: the recursion equations generated by 'recdef' for
  1007 function 'f' are now called f.simps instead of f.rules; if all
  1008 termination conditions are proved automatically, these simplification
  1009 rules are added to the simpset, as in primrec; rules may be named
  1010 individually as well, resulting in a separate list of theorems for
  1011 each equation;
  1012 
  1013 * HOL/While is a new theory that provides a while-combinator. It
  1014 permits the definition of tail-recursive functions without the
  1015 provision of a termination measure. The latter is necessary once the
  1016 invariant proof rule for while is applied.
  1017 
  1018 * HOL: new (overloaded) notation for the set of elements below/above
  1019 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1020 
  1021 * HOL: theorems impI, allI, ballI bound as "strip";
  1022 
  1023 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1024 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1025 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1026 
  1027 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1028 
  1029 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1030 main HOL, but was unused);
  1031 
  1032 * HOL: fewer consts declared as global (e.g. have to refer to
  1033 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1034 
  1035 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1036 in case of overlap with user translations (e.g. judgements over
  1037 tuples); (note that the underlying logical represenation is still
  1038 bogus);
  1039 
  1040 
  1041 *** ZF ***
  1042 
  1043 * ZF: simplification automatically cancels common terms in arithmetic
  1044 expressions over nat and int;
  1045 
  1046 * ZF: new treatment of nat to minimize type-checking: all operators
  1047 coerce their operands to a natural number using the function natify,
  1048 making the algebraic laws unconditional;
  1049 
  1050 * ZF: as above, for int: operators coerce their operands to an integer
  1051 using the function intify;
  1052 
  1053 * ZF: the integer library now contains many of the usual laws for the
  1054 orderings, including $<=, and monotonicity laws for $+ and $*;
  1055 
  1056 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1057 simplification;
  1058 
  1059 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1060 to the simplifier and classical reasoner simultaneously;
  1061 
  1062 
  1063 *** General ***
  1064 
  1065 * Provers: blast_tac now handles actual object-logic rules as
  1066 assumptions; note that auto_tac uses blast_tac internally as well;
  1067 
  1068 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1069 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1070 
  1071 * Provers: delrules now handles destruct rules as well (no longer need
  1072 explicit make_elim);
  1073 
  1074 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1075   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1076 use instead the strong form,
  1077   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1078 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1079 from destruct-rules;
  1080 
  1081 * Provers: Simplifier.easy_setup provides a fast path to basic
  1082 Simplifier setup for new object-logics;
  1083 
  1084 * Pure: AST translation rules no longer require constant head on LHS;
  1085 
  1086 * Pure: improved name spaces: ambiguous output is qualified; support
  1087 for hiding of names;
  1088 
  1089 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1090 XSYMBOL_HOME; no longer need to do manual configuration in most
  1091 situations;
  1092 
  1093 * system: compression of ML heaps images may now be controlled via -c
  1094 option of isabelle and isatool usedir (currently only observed by
  1095 Poly/ML);
  1096 
  1097 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1098 useful for remote X11);
  1099 
  1100 * system: provide TAGS file for Isabelle sources;
  1101 
  1102 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1103 order;
  1104 
  1105 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1106 timing flag supersedes proof_timing and Toplevel.trace;
  1107 
  1108 * ML: new combinators |>> and |>>> for incremental transformations
  1109 with secondary results (e.g. certain theory extensions):
  1110 
  1111 * ML: PureThy.add_defs gets additional argument to indicate potential
  1112 overloading (usually false);
  1113 
  1114 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1115 results;
  1116 
  1117 
  1118 
  1119 New in Isabelle99 (October 1999)
  1120 --------------------------------
  1121 
  1122 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1123 
  1124 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1125 are no longer simplified.  (This allows the simplifier to unfold recursive
  1126 functional programs.)  To restore the old behaviour, declare
  1127 
  1128     Delcongs [if_weak_cong];
  1129 
  1130 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1131 complement;
  1132 
  1133 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1134 
  1135 * HOL/datatype: mutual_induct_tac no longer exists --
  1136   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1137 
  1138 * HOL/typedef: fixed type inference for representing set; type
  1139 arguments now have to occur explicitly on the rhs as type constraints;
  1140 
  1141 * ZF: The con_defs part of an inductive definition may no longer refer
  1142 to constants declared in the same theory;
  1143 
  1144 * HOL, ZF: the function mk_cases, generated by the inductive
  1145 definition package, has lost an argument.  To simplify its result, it
  1146 uses the default simpset instead of a supplied list of theorems.
  1147 
  1148 * HOL/List: the constructors of type list are now Nil and Cons;
  1149 
  1150 * Simplifier: the type of the infix ML functions
  1151         setSSolver addSSolver setSolver addSolver
  1152 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1153 for packaging solvers. A solver is created via
  1154         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1155 where the string argument is only a comment.
  1156 
  1157 
  1158 *** Proof tools ***
  1159 
  1160 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1161 decision procedure for linear arithmetic. Currently it is used for
  1162 types `nat', `int', and `real' in HOL (see below); it can, should and
  1163 will be instantiated for other types and logics as well.
  1164 
  1165 * The simplifier now accepts rewrite rules with flexible heads, eg
  1166      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1167   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1168   matching.
  1169 
  1170 
  1171 *** General ***
  1172 
  1173 * New Isabelle/Isar subsystem provides an alternative to traditional
  1174 tactical theorem proving; together with the ProofGeneral/isar user
  1175 interface it offers an interactive environment for developing human
  1176 readable proof documents (Isar == Intelligible semi-automated
  1177 reasoning); for further information see isatool doc isar-ref,
  1178 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1179 
  1180 * improved and simplified presentation of theories: better HTML markup
  1181 (including colors), graph views in several sizes; isatool usedir now
  1182 provides a proper interface for user theories (via -P option); actual
  1183 document preparation based on (PDF)LaTeX is available as well (for
  1184 new-style theories only); see isatool doc system for more information;
  1185 
  1186 * native support for Proof General, both for classic Isabelle and
  1187 Isabelle/Isar;
  1188 
  1189 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1190 using the graph browser tool;
  1191 
  1192 * Isabelle manuals now also available as PDF;
  1193 
  1194 * theory loader rewritten from scratch (may not be fully
  1195 bug-compatible); old loadpath variable has been replaced by show_path,
  1196 add_path, del_path, reset_path functions; new operations such as
  1197 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1198 isatool doc ref);
  1199 
  1200 * improved isatool install: option -k creates KDE application icon,
  1201 option -p DIR installs standalone binaries;
  1202 
  1203 * added ML_PLATFORM setting (useful for cross-platform installations);
  1204 more robust handling of platform specific ML images for SML/NJ;
  1205 
  1206 * the settings environment is now statically scoped, i.e. it is never
  1207 created again in sub-processes invoked from isabelle, isatool, or
  1208 Isabelle;
  1209 
  1210 * path element specification '~~' refers to '$ISABELLE_HOME';
  1211 
  1212 * in locales, the "assumes" and "defines" parts may be omitted if
  1213 empty;
  1214 
  1215 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1216 long arrows);
  1217 
  1218 * new print_mode "HTML";
  1219 
  1220 * new flag show_tags controls display of tags of theorems (which are
  1221 basically just comments that may be attached by some tools);
  1222 
  1223 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1224 mode and goal output format:
  1225 
  1226 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1227 244c244
  1228 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1229 ---
  1230 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1231 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1232 181c181
  1233 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1234 ---
  1235 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1236 
  1237 * function bind_thms stores lists of theorems (cf. bind_thm);
  1238 
  1239 * new shorthand tactics ftac, eatac, datac, fatac;
  1240 
  1241 * qed (and friends) now accept "" as result name; in that case the
  1242 theorem is not stored, but proper checks and presentation of the
  1243 result still apply;
  1244 
  1245 * theorem database now also indexes constants "Trueprop", "all",
  1246 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1247 
  1248 
  1249 *** HOL ***
  1250 
  1251 ** HOL arithmetic **
  1252 
  1253 * There are now decision procedures for linear arithmetic over nat and
  1254 int:
  1255 
  1256 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1257 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1258 are treated as atomic; subformulae not involving type `nat' or `int'
  1259 are ignored; quantified subformulae are ignored unless they are
  1260 positive universal or negative existential. The tactic has to be
  1261 invoked by hand and can be a little bit slow. In particular, the
  1262 running time is exponential in the number of occurrences of `min' and
  1263 `max', and `-' on `nat'.
  1264 
  1265 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1266 (negated) (in)equalities among the premises and the conclusion into
  1267 account (i.e. no compound formulae) and does not know about `min' and
  1268 `max', and `-' on `nat'. It is fast and is used automatically by the
  1269 simplifier.
  1270 
  1271 NB: At the moment, these decision procedures do not cope with mixed
  1272 nat/int formulae where the two parts interact, such as `m < n ==>
  1273 int(m) < int(n)'.
  1274 
  1275 * HOL/Numeral provides a generic theory of numerals (encoded
  1276 efficiently as bit strings); setup for types nat/int/real is in place;
  1277 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1278 int, existing theories and proof scripts may require a few additional
  1279 type constraints;
  1280 
  1281 * integer division and remainder can now be performed on constant
  1282 arguments;
  1283 
  1284 * many properties of integer multiplication, division and remainder
  1285 are now available;
  1286 
  1287 * An interface to the Stanford Validity Checker (SVC) is available through the
  1288 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1289 are proved automatically.  SVC must be installed separately, and its results
  1290 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1291 invocation of the underlying oracle).  For SVC see
  1292   http://verify.stanford.edu/SVC
  1293 
  1294 * IsaMakefile: the HOL-Real target now builds an actual image;
  1295 
  1296 
  1297 ** HOL misc **
  1298 
  1299 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1300 (in Isabelle/Isar) -- by Gertrud Bauer;
  1301 
  1302 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1303 analysis for assembly languages with subtypes;
  1304 
  1305 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1306 -- avoids syntactic ambiguities and treats state, transition, and
  1307 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1308 changed syntax and (many) tactics;
  1309 
  1310 * HOL/inductive: Now also handles more general introduction rules such
  1311   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1312   theorems are now maintained within the theory (maintained via the
  1313   "mono" attribute);
  1314 
  1315 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1316   (using function types) such as
  1317 
  1318   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1319 
  1320 * HOL/record: record_simproc (part of the default simpset) takes care
  1321 of selectors applied to updated records; record_split_tac is no longer
  1322 part of the default claset; update_defs may now be removed from the
  1323 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1324 
  1325   claset_ref () := claset() addSWrapper record_split_wrapper;
  1326   Delsimprocs [record_simproc]
  1327 
  1328 * HOL/typedef: fixed type inference for representing set; type
  1329 arguments now have to occur explicitly on the rhs as type constraints;
  1330 
  1331 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1332 names rather than an ML expression;
  1333 
  1334 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1335 supplied later.  Program schemes can be defined, such as
  1336     "While B C s = (if B s then While B C (C s) else s)"
  1337 where the well-founded relation can be chosen after B and C have been given.
  1338 
  1339 * HOL/List: the constructors of type list are now Nil and Cons;
  1340 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1341 course, ML tools referring to List.list.op # etc. have to be adapted;
  1342 
  1343 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1344 disabled by default; run isabelle with option -m HOL to get back to
  1345 the original Gordon/HOL-style output;
  1346 
  1347 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1348 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1349 
  1350 * HOL basic syntax simplified (more orthogonal): all variants of
  1351 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1352 Eps operator is provided as well: "SOME x. P[x]";
  1353 
  1354 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1355 
  1356 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1357 thus available for user theories;
  1358 
  1359 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1360 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1361 time;
  1362 
  1363 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1364 several times and then mp;
  1365 
  1366 
  1367 *** LK ***
  1368 
  1369 * the notation <<...>> is now available as a notation for sequences of
  1370 formulas;
  1371 
  1372 * the simplifier is now installed
  1373 
  1374 * the axiom system has been generalized (thanks to Soren Heilmann)
  1375 
  1376 * the classical reasoner now has a default rule database
  1377 
  1378 
  1379 *** ZF ***
  1380 
  1381 * new primrec section allows primitive recursive functions to be given
  1382 directly (as in HOL) over datatypes and the natural numbers;
  1383 
  1384 * new tactics induct_tac and exhaust_tac for induction (or case
  1385 analysis) over datatypes and the natural numbers;
  1386 
  1387 * the datatype declaration of type T now defines the recursor T_rec;
  1388 
  1389 * simplification automatically does freeness reasoning for datatype
  1390 constructors;
  1391 
  1392 * automatic type-inference, with AddTCs command to insert new
  1393 type-checking rules;
  1394 
  1395 * datatype introduction rules are now added as Safe Introduction rules
  1396 to the claset;
  1397 
  1398 * the syntax "if P then x else y" is now available in addition to
  1399 if(P,x,y);
  1400 
  1401 
  1402 *** Internal programming interfaces ***
  1403 
  1404 * tuned simplifier trace output; new flag debug_simp;
  1405 
  1406 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1407 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1408 
  1409 * AxClass.axclass_tac lost the theory argument;
  1410 
  1411 * tuned current_goals_markers semantics: begin / end goal avoids
  1412 printing empty lines;
  1413 
  1414 * removed prs and prs_fn hook, which was broken because it did not
  1415 include \n in its semantics, forcing writeln to add one
  1416 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1417 string -> unit if you really want to output text without newline;
  1418 
  1419 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1420 plain output, interface builders may have to enable 'isabelle_font'
  1421 mode to get Isabelle font glyphs as before;
  1422 
  1423 * refined token_translation interface; INCOMPATIBILITY: output length
  1424 now of type real instead of int;
  1425 
  1426 * theory loader actions may be traced via new ThyInfo.add_hook
  1427 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1428 your own database of information attached to *whole* theories -- as
  1429 opposed to intra-theory data slots offered via TheoryDataFun;
  1430 
  1431 * proper handling of dangling sort hypotheses (at last!);
  1432 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1433 extra sort hypotheses that can be witnessed from the type signature;
  1434 the force_strip_shyps flag is gone, any remaining shyps are simply
  1435 left in the theorem (with a warning issued by strip_shyps_warning);
  1436 
  1437 
  1438 
  1439 New in Isabelle98-1 (October 1998)
  1440 ----------------------------------
  1441 
  1442 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1443 
  1444 * several changes of automated proof tools;
  1445 
  1446 * HOL: major changes to the inductive and datatype packages, including
  1447 some minor incompatibilities of theory syntax;
  1448 
  1449 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1450 called `inj_on';
  1451 
  1452 * HOL: removed duplicate thms in Arith:
  1453   less_imp_add_less  should be replaced by  trans_less_add1
  1454   le_imp_add_le      should be replaced by  trans_le_add1
  1455 
  1456 * HOL: unary minus is now overloaded (new type constraints may be
  1457 required);
  1458 
  1459 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1460 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1461 now taken as an integer constant.
  1462 
  1463 * Pure: ML function 'theory_of' renamed to 'theory';
  1464 
  1465 
  1466 *** Proof tools ***
  1467 
  1468 * Simplifier:
  1469   1. Asm_full_simp_tac is now more aggressive.
  1470      1. It will sometimes reorient premises if that increases their power to
  1471         simplify.
  1472      2. It does no longer proceed strictly from left to right but may also
  1473         rotate premises to achieve further simplification.
  1474      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1475      old Asm_full_simp_tac in that it does not rotate premises.
  1476   2. The simplifier now knows a little bit about nat-arithmetic.
  1477 
  1478 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1479 allows for selected deletion of wrappers, by introduction of names for
  1480 wrapper functionals.  This implies that addbefore, addSbefore,
  1481 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1482 and that adding two tactics with the same name overwrites the first
  1483 one (emitting a warning).
  1484   type wrapper = (int -> tactic) -> (int -> tactic)
  1485   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1486   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1487   delWrapper, delSWrapper: claset *  string            -> claset
  1488   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1489 
  1490 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1491 semantics; addbefore now affects only the unsafe part of step_tac
  1492 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1493 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1494 by Force_tac;
  1495 
  1496 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1497 compWrapper; added safe wrapper (and access functions for it);
  1498 
  1499 * HOL/split_all_tac is now much faster and fails if there is nothing
  1500 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1501 and the names of the automatically generated variables have changed.
  1502 split_all_tac has moved within claset() from unsafe wrappers to safe
  1503 wrappers, which means that !!-bound variables are split much more
  1504 aggressively, and safe_tac and clarify_tac now split such variables.
  1505 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1506 Note: the same holds for record_split_tac, which does the job of
  1507 split_all_tac for record fields.
  1508 
  1509 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1510 permanently to the default simpset using Addsplits just like
  1511 Addsimps. They can be removed via Delsplits just like
  1512 Delsimps. Lower-case versions are also available.
  1513 
  1514 * HOL/Simplifier: The rule split_if is now part of the default
  1515 simpset. This means that the simplifier will eliminate all occurrences
  1516 of if-then-else in the conclusion of a goal. To prevent this, you can
  1517 either remove split_if completely from the default simpset by
  1518 `Delsplits [split_if]' or remove it in a specific call of the
  1519 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1520 other case splitting rules to/from the default simpset: every datatype
  1521 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1522 t is the name of the datatype).
  1523 
  1524 * Classical reasoner / Simplifier combination: new force_tac (and
  1525 derivatives Force_tac, force) combines rewriting and classical
  1526 reasoning (and whatever other tools) similarly to auto_tac, but is
  1527 aimed to solve the given subgoal completely.
  1528 
  1529 
  1530 *** General ***
  1531 
  1532 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1533 and `goalw': the theory is no longer needed as an explicit argument -
  1534 the current theory context is used; assumptions are no longer returned
  1535 at the ML-level unless one of them starts with ==> or !!; it is
  1536 recommended to convert to these new commands using isatool fixgoal
  1537 (backup your sources first!);
  1538 
  1539 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1540 the current theory context, and 'theory' to lookup stored theories;
  1541 
  1542 * new theory section 'locale' for declaring constants, assumptions and
  1543 definitions that have local scope;
  1544 
  1545 * new theory section 'nonterminals' for purely syntactic types;
  1546 
  1547 * new theory section 'setup' for generic ML setup functions
  1548 (e.g. package initialization);
  1549 
  1550 * the distribution now includes Isabelle icons: see
  1551 lib/logo/isabelle-{small,tiny}.xpm;
  1552 
  1553 * isatool install - install binaries with absolute references to
  1554 ISABELLE_HOME/bin;
  1555 
  1556 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1557 
  1558 * print mode 'emacs' reserved for Isamode;
  1559 
  1560 * support multiple print (ast) translations per constant name;
  1561 
  1562 * theorems involving oracles are now printed with a suffixed [!];
  1563 
  1564 
  1565 *** HOL ***
  1566 
  1567 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1568 
  1569 * HOL/inductive package reorganized and improved: now supports mutual
  1570 definitions such as
  1571 
  1572   inductive EVEN ODD
  1573     intrs
  1574       null "0 : EVEN"
  1575       oddI "n : EVEN ==> Suc n : ODD"
  1576       evenI "n : ODD ==> Suc n : EVEN"
  1577 
  1578 new theorem list "elims" contains an elimination rule for each of the
  1579 recursive sets; inductive definitions now handle disjunctive premises
  1580 correctly (also ZF);
  1581 
  1582 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1583 "mutual_induct" no longer exists - the induction rule is always
  1584 contained in "induct";
  1585 
  1586 
  1587 * HOL/datatype package re-implemented and greatly improved: now
  1588 supports mutually recursive datatypes such as
  1589 
  1590   datatype
  1591     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1592             | SUM ('a aexp) ('a aexp)
  1593             | DIFF ('a aexp) ('a aexp)
  1594             | NUM 'a
  1595   and
  1596     'a bexp = LESS ('a aexp) ('a aexp)
  1597             | AND ('a bexp) ('a bexp)
  1598             | OR ('a bexp) ('a bexp)
  1599 
  1600 as well as indirectly recursive datatypes such as
  1601 
  1602   datatype
  1603     ('a, 'b) term = Var 'a
  1604                   | App 'b ((('a, 'b) term) list)
  1605 
  1606 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1607 induction on mutually / indirectly recursive datatypes.
  1608 
  1609 Primrec equations are now stored in theory and can be accessed via
  1610 <function_name>.simps.
  1611 
  1612 INCOMPATIBILITIES:
  1613 
  1614   - Theories using datatypes must now have theory Datatype as an
  1615     ancestor.
  1616   - The specific <typename>.induct_tac no longer exists - use the
  1617     generic induct_tac instead.
  1618   - natE has been renamed to nat.exhaust - use exhaust_tac
  1619     instead of res_inst_tac ... natE. Note that the variable
  1620     names in nat.exhaust differ from the names in natE, this
  1621     may cause some "fragile" proofs to fail.
  1622   - The theorems split_<typename>_case and split_<typename>_case_asm
  1623     have been renamed to <typename>.split and <typename>.split_asm.
  1624   - Since default sorts of type variables are now handled correctly,
  1625     some datatype definitions may have to be annotated with explicit
  1626     sort constraints.
  1627   - Primrec definitions no longer require function name and type
  1628     of recursive argument.
  1629 
  1630 Consider using isatool fixdatatype to adapt your theories and proof
  1631 scripts to the new package (backup your sources first!).
  1632 
  1633 
  1634 * HOL/record package: considerably improved implementation; now
  1635 includes concrete syntax for record types, terms, updates; theorems
  1636 for surjective pairing and splitting !!-bound record variables; proof
  1637 support is as follows:
  1638 
  1639   1) standard conversions (selectors or updates applied to record
  1640 constructor terms) are part of the standard simpset;
  1641 
  1642   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1643 made part of standard simpset and claset via addIffs;
  1644 
  1645   3) a tactic for record field splitting (record_split_tac) is part of
  1646 the standard claset (addSWrapper);
  1647 
  1648 To get a better idea about these rules you may retrieve them via
  1649 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1650 the name of your record type.
  1651 
  1652 The split tactic 3) conceptually simplifies by the following rule:
  1653 
  1654   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1655 
  1656 Thus any record variable that is bound by meta-all will automatically
  1657 blow up into some record constructor term, consequently the
  1658 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1659 solve record problems automatically.
  1660 
  1661 
  1662 * reorganized the main HOL image: HOL/Integ and String loaded by
  1663 default; theory Main includes everything;
  1664 
  1665 * automatic simplification of integer sums and comparisons, using cancellation;
  1666 
  1667 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1668 
  1669 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1670 
  1671 * many new identities for unions, intersections, set difference, etc.;
  1672 
  1673 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1674 called split_if, split_split, split_sum_case and split_nat_case (to go
  1675 with add/delsplits);
  1676 
  1677 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1678 (?x::unit) = (); this is made part of the default simpset, which COULD
  1679 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1680 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1681 unit_abs_eta_conv is added in order to counter the effect of
  1682 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1683 %u.f();
  1684 
  1685 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1686 makes more sense);
  1687 
  1688 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1689   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1690   disjointness reasoning but breaking a few old proofs.
  1691 
  1692 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1693 to 'converse' from 'inverse' (for compatibility with ZF and some
  1694 literature);
  1695 
  1696 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1697 the well-founded relation;
  1698 
  1699 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1700     Compl A.  The "Compl" syntax remains available as input syntax for this
  1701     release ONLY.
  1702 
  1703 * HOL/Update: new theory of function updates:
  1704     f(a:=b) == %x. if x=a then b else f x
  1705 may also be iterated as in f(a:=b,c:=d,...);
  1706 
  1707 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1708 
  1709 * HOL/List:
  1710   - new function list_update written xs[i:=v] that updates the i-th
  1711     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1712   - new function `upt' written [i..j(] which generates the list
  1713     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1714     bound write [i..j], which is a shorthand for [i..j+1(].
  1715   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1716 
  1717 * HOL/Arith:
  1718   - removed 'pred' (predecessor) function;
  1719   - generalized some theorems about n-1;
  1720   - many new laws about "div" and "mod";
  1721   - new laws about greatest common divisors (see theory ex/Primes);
  1722 
  1723 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1724 instead of "inverse";
  1725 
  1726 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1727   of the multiset ordering;
  1728 
  1729 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1730   (not included by default);
  1731 
  1732 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1733 
  1734 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1735   programs, i.e. different program variables may have different types.
  1736 
  1737 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1738   [previously, this check worked only if the rewrite rule was unconditional]
  1739   Now rew can involve either definitions or equalities (either == or =).
  1740 
  1741 
  1742 *** ZF ***
  1743 
  1744 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1745   only the theorems proved on ZF.ML;
  1746 
  1747 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1748   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1749   disjointness reasoning but breaking a few old proofs.
  1750 
  1751 * ZF/Update: new theory of function updates
  1752     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1753   may also be iterated as in f(a:=b,c:=d,...);
  1754 
  1755 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1756 
  1757 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1758   [previously, this check worked only if the rewrite rule was unconditional]
  1759   Now rew can involve either definitions or equalities (either == or =).
  1760 
  1761 * case_tac provided for compatibility with HOL
  1762     (like the old excluded_middle_tac, but with subgoals swapped)
  1763 
  1764 
  1765 *** Internal programming interfaces ***
  1766 
  1767 * Pure: several new basic modules made available for general use, see
  1768 also src/Pure/README;
  1769 
  1770 * improved the theory data mechanism to support encapsulation (data
  1771 kind name replaced by private Object.kind, acting as authorization
  1772 key); new type-safe user interface via functor TheoryDataFun; generic
  1773 print_data function becomes basically useless;
  1774 
  1775 * removed global_names compatibility flag -- all theory declarations
  1776 are qualified by default;
  1777 
  1778 * module Pure/Syntax now offers quote / antiquote translation
  1779 functions (useful for Hoare logic etc. with implicit dependencies);
  1780 see HOL/ex/Antiquote for an example use;
  1781 
  1782 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1783 cterm -> thm;
  1784 
  1785 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1786 subgoal;
  1787 
  1788 * Display.print_goals function moved to Locale.print_goals;
  1789 
  1790 * standard print function for goals supports current_goals_markers
  1791 variable for marking begin of proof, end of proof, start of goal; the
  1792 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1793 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1794 for example;
  1795 
  1796 
  1797 
  1798 New in Isabelle98 (January 1998)
  1799 --------------------------------
  1800 
  1801 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1802 
  1803 * changed lexical syntax of terms / types: dots made part of long
  1804 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1805 
  1806 * simpset (and claset) reference variable replaced by functions
  1807 simpset / simpset_ref;
  1808 
  1809 * no longer supports theory aliases (via merge) and non-trivial
  1810 implicit merge of thms' signatures;
  1811 
  1812 * most internal names of constants changed due to qualified names;
  1813 
  1814 * changed Pure/Sequence interface (see Pure/seq.ML);
  1815 
  1816 
  1817 *** General Changes ***
  1818 
  1819 * hierachically structured name spaces (for consts, types, axms, thms
  1820 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1821 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1822 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1823 long_names for fully qualified output names; NOTE: ML programs
  1824 (special tactics, packages etc.) referring to internal names may have
  1825 to be adapted to cope with fully qualified names; in case of severe
  1826 backward campatibility problems try setting 'global_names' at compile
  1827 time to have enrything declared within a flat name space; one may also
  1828 fine tune name declarations in theories via the 'global' and 'local'
  1829 section;
  1830 
  1831 * reimplemented the implicit simpset and claset using the new anytype
  1832 data filed in signatures; references simpset:simpset ref etc. are
  1833 replaced by functions simpset:unit->simpset and
  1834 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1835 to patch your ML files accordingly;
  1836 
  1837 * HTML output now includes theory graph data for display with Java
  1838 applet or isatool browser; data generated automatically via isatool
  1839 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1840 
  1841 * defs may now be conditional; improved rewrite_goals_tac to handle
  1842 conditional equations;
  1843 
  1844 * defs now admits additional type arguments, using TYPE('a) syntax;
  1845 
  1846 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1847 creates a new theory node; implicit merge of thms' signatures is
  1848 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1849 transfer:theory->thm->thm in (rare) cases;
  1850 
  1851 * improved handling of draft signatures / theories; draft thms (and
  1852 ctyps, cterms) are automatically promoted to real ones;
  1853 
  1854 * slightly changed interfaces for oracles: admit many per theory, named
  1855 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1856 
  1857 * print_goals: optional output of const types (set show_consts and
  1858 show_types);
  1859 
  1860 * improved output of warnings (###) and errors (***);
  1861 
  1862 * subgoal_tac displays a warning if the new subgoal has type variables;
  1863 
  1864 * removed old README and Makefiles;
  1865 
  1866 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1867 
  1868 * removed obsolete init_pps and init_database;
  1869 
  1870 * deleted the obsolete tactical STATE, which was declared by
  1871     fun STATE tacfun st = tacfun st st;
  1872 
  1873 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1874 (which abbreviates $HOME);
  1875 
  1876 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1877 use isatool fixseq to adapt your ML programs (this works for fully
  1878 qualified references to the Sequence structure only!);
  1879 
  1880 * use_thy no longer requires writable current directory; it always
  1881 reloads .ML *and* .thy file, if either one is out of date;
  1882 
  1883 
  1884 *** Classical Reasoner ***
  1885 
  1886 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1887 tactics that use classical reasoning to simplify a subgoal without
  1888 splitting it into several subgoals;
  1889 
  1890 * Safe_tac: like safe_tac but uses the default claset;
  1891 
  1892 
  1893 *** Simplifier ***
  1894 
  1895 * added simplification meta rules:
  1896     (asm_)(full_)simplify: simpset -> thm -> thm;
  1897 
  1898 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1899 logics (again);
  1900 
  1901 * added prems argument to simplification procedures;
  1902 
  1903 * HOL, FOL, ZF: added infix function `addsplits':
  1904   instead of `<simpset> setloop (split_tac <thms>)'
  1905   you can simply write `<simpset> addsplits <thms>'
  1906 
  1907 
  1908 *** Syntax ***
  1909 
  1910 * TYPE('a) syntax for type reflection terms;
  1911 
  1912 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1913 
  1914 * pretty printer: changed order of mixfix annotation preference (again!);
  1915 
  1916 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1917 
  1918 
  1919 *** HOL ***
  1920 
  1921 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1922   with `addloop' of the simplifier to faciliate case splitting in premises.
  1923 
  1924 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1925 
  1926 * HOL/Auth: new protocol proofs including some for the Internet
  1927   protocol TLS;
  1928 
  1929 * HOL/Map: new theory of `maps' a la VDM;
  1930 
  1931 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1932 cancelling out common nat summands from =, <, <= (in)equalities, or
  1933 differences; simplification procedures nat_cancel_factor for
  1934 cancelling common factor from =, <, <= (in)equalities over natural
  1935 sums; nat_cancel contains both kinds of procedures, it is installed by
  1936 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1937 
  1938 * HOL/simplifier: terms of the form
  1939   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1940   are rewritten to
  1941   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1942   and those of the form
  1943   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1944   are rewritten to
  1945   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1946 
  1947 * HOL/datatype
  1948   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1949 
  1950   P(t_case f1 ... fn x) =
  1951      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1952         ...
  1953        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1954      )
  1955 
  1956   and a theorem `split_t_case_asm' of the form
  1957 
  1958   P(t_case f1 ... fn x) =
  1959     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1960         ...
  1961        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1962      )
  1963   which can be added to a simpset via `addsplits'. The existing theorems
  1964   expand_list_case and expand_option_case have been renamed to
  1965   split_list_case and split_option_case.
  1966 
  1967 * HOL/Arithmetic:
  1968   - `pred n' is automatically converted to `n-1'.
  1969     Users are strongly encouraged not to use `pred' any longer,
  1970     because it will disappear altogether at some point.
  1971   - Users are strongly encouraged to write "0 < n" rather than
  1972     "n ~= 0". Theorems and proof tools have been modified towards this
  1973     `standard'.
  1974 
  1975 * HOL/Lists:
  1976   the function "set_of_list" has been renamed "set" (and its theorems too);
  1977   the function "nth" now takes its arguments in the reverse order and
  1978   has acquired the infix notation "!" as in "xs!n".
  1979 
  1980 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1981 
  1982 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1983   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1984 
  1985 * HOL/record: extensible records with schematic structural subtyping
  1986 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1987 still lacks various theorems and concrete record syntax;
  1988 
  1989 
  1990 *** HOLCF ***
  1991 
  1992 * removed "axioms" and "generated by" sections;
  1993 
  1994 * replaced "ops" section by extended "consts" section, which is capable of
  1995   handling the continuous function space "->" directly;
  1996 
  1997 * domain package:
  1998   . proves theorems immediately and stores them in the theory,
  1999   . creates hierachical name space,
  2000   . now uses normal mixfix annotations (instead of cinfix...),
  2001   . minor changes to some names and values (for consistency),
  2002   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2003   . separator between mutual domain defs: changed "," to "and",
  2004   . improved handling of sort constraints;  now they have to
  2005     appear on the left-hand side of the equations only;
  2006 
  2007 * fixed LAM <x,y,zs>.b syntax;
  2008 
  2009 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2010 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2011 
  2012 
  2013 *** FOL and ZF ***
  2014 
  2015 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2016   with `addloop' of the simplifier to faciliate case splitting in premises.
  2017 
  2018 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2019 in HOL, they strip ALL and --> from proved theorems;
  2020 
  2021 
  2022 
  2023 New in Isabelle94-8 (May 1997)
  2024 ------------------------------
  2025 
  2026 *** General Changes ***
  2027 
  2028 * new utilities to build / run / maintain Isabelle etc. (in parts
  2029 still somewhat experimental); old Makefiles etc. still functional;
  2030 
  2031 * new 'Isabelle System Manual';
  2032 
  2033 * INSTALL text, together with ./configure and ./build scripts;
  2034 
  2035 * reimplemented type inference for greater efficiency, better error
  2036 messages and clean internal interface;
  2037 
  2038 * prlim command for dealing with lots of subgoals (an easier way of
  2039 setting goals_limit);
  2040 
  2041 
  2042 *** Syntax ***
  2043 
  2044 * supports alternative (named) syntax tables (parser and pretty
  2045 printer); internal interface is provided by add_modesyntax(_i);
  2046 
  2047 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2048 be used in conjunction with the Isabelle symbol font; uses the
  2049 "symbols" syntax table;
  2050 
  2051 * added token_translation interface (may translate name tokens in
  2052 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2053 the current print_mode); IMPORTANT: user print translation functions
  2054 are responsible for marking newly introduced bounds
  2055 (Syntax.mark_boundT);
  2056 
  2057 * token translations for modes "xterm" and "xterm_color" that display
  2058 names in bold, underline etc. or colors (which requires a color
  2059 version of xterm);
  2060 
  2061 * infixes may now be declared with names independent of their syntax;
  2062 
  2063 * added typed_print_translation (like print_translation, but may
  2064 access type of constant);
  2065 
  2066 
  2067 *** Classical Reasoner ***
  2068 
  2069 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2070 some limitations.  Blast_tac...
  2071   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2072   + ignores elimination rules that don't have the correct format
  2073         (the conclusion MUST be a formula variable)
  2074   + ignores types, which can make HOL proofs fail
  2075   + rules must not require higher-order unification, e.g. apply_type in ZF
  2076     [message "Function Var's argument not a bound variable" relates to this]
  2077   + its proof strategy is more general but can actually be slower
  2078 
  2079 * substitution with equality assumptions no longer permutes other
  2080 assumptions;
  2081 
  2082 * minor changes in semantics of addafter (now called addaltern); renamed
  2083 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2084 (and access functions for it);
  2085 
  2086 * improved combination of classical reasoner and simplifier:
  2087   + functions for handling clasimpsets
  2088   + improvement of addss: now the simplifier is called _after_ the
  2089     safe steps.
  2090   + safe variant of addss called addSss: uses safe simplifications
  2091     _during_ the safe steps. It is more complete as it allows multiple
  2092     instantiations of unknowns (e.g. with slow_tac).
  2093 
  2094 *** Simplifier ***
  2095 
  2096 * added interface for simplification procedures (functions that
  2097 produce *proven* rewrite rules on the fly, depending on current
  2098 redex);
  2099 
  2100 * ordering on terms as parameter (used for ordered rewriting);
  2101 
  2102 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2103 
  2104 * the solver is now split into a safe and an unsafe part.
  2105 This should be invisible for the normal user, except that the
  2106 functions setsolver and addsolver have been renamed to setSolver and
  2107 addSolver; added safe_asm_full_simp_tac;
  2108 
  2109 
  2110 *** HOL ***
  2111 
  2112 * a generic induction tactic `induct_tac' which works for all datatypes and
  2113 also for type `nat';
  2114 
  2115 * a generic case distinction tactic `exhaust_tac' which works for all
  2116 datatypes and also for type `nat';
  2117 
  2118 * each datatype comes with a function `size';
  2119 
  2120 * patterns in case expressions allow tuple patterns as arguments to
  2121 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2122 
  2123 * primrec now also works with type nat;
  2124 
  2125 * recdef: a new declaration form, allows general recursive functions to be
  2126 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2127 
  2128 * the constant for negation has been renamed from "not" to "Not" to
  2129 harmonize with FOL, ZF, LK, etc.;
  2130 
  2131 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2132 infinite lists;
  2133 
  2134 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2135 
  2136 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2137 problems in commutative rings, using axiomatic type classes for + and *;
  2138 
  2139 * more examples in HOL/MiniML and HOL/Auth;
  2140 
  2141 * more default rewrite rules for quantifiers, union/intersection;
  2142 
  2143 * a new constant `arbitrary == @x.False';
  2144 
  2145 * HOLCF/IOA replaces old HOL/IOA;
  2146 
  2147 * HOLCF changes: derived all rules and arities
  2148   + axiomatic type classes instead of classes
  2149   + typedef instead of faking type definitions
  2150   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2151   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2152   + eliminated the types void, one, tr
  2153   + use unit lift and bool lift (with translations) instead of one and tr
  2154   + eliminated blift from Lift3.thy (use Def instead of blift)
  2155   all eliminated rules are derived as theorems --> no visible changes ;
  2156 
  2157 
  2158 *** ZF ***
  2159 
  2160 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2161 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2162 as ZF_cs addSIs [equalityI];
  2163 
  2164 
  2165 
  2166 New in Isabelle94-7 (November 96)
  2167 ---------------------------------
  2168 
  2169 * allowing negative levels (as offsets) in prlev and choplev;
  2170 
  2171 * super-linear speedup for large simplifications;
  2172 
  2173 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2174 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2175 FAIL); can suppress it using the command Delsimps (ex_simps @
  2176 all_simps); De Morgan laws are also now included, by default;
  2177 
  2178 * improved printing of ==>  :  ~:
  2179 
  2180 * new object-logic "Sequents" adds linear logic, while replacing LK
  2181 and Modal (thanks to Sara Kalvala);
  2182 
  2183 * HOL/Auth: correctness proofs for authentication protocols;
  2184 
  2185 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2186 examples on HOL/Auth);
  2187 
  2188 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2189 the rewriter and classical reasoner simultaneously;
  2190 
  2191 * function uresult no longer returns theorems in "standard" format;
  2192 regain previous version by: val uresult = standard o uresult;
  2193 
  2194 
  2195 
  2196 New in Isabelle94-6
  2197 -------------------
  2198 
  2199 * oracles -- these establish an interface between Isabelle and trusted
  2200 external reasoners, which may deliver results as theorems;
  2201 
  2202 * proof objects (in particular record all uses of oracles);
  2203 
  2204 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2205 
  2206 * "constdefs" section in theory files;
  2207 
  2208 * "primrec" section (HOL) no longer requires names;
  2209 
  2210 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2211 
  2212 
  2213 
  2214 New in Isabelle94-5
  2215 -------------------
  2216 
  2217 * reduced space requirements;
  2218 
  2219 * automatic HTML generation from theories;
  2220 
  2221 * theory files no longer require "..." (quotes) around most types;
  2222 
  2223 * new examples, including two proofs of the Church-Rosser theorem;
  2224 
  2225 * non-curried (1994) version of HOL is no longer distributed;
  2226 
  2227 
  2228 
  2229 New in Isabelle94-4
  2230 -------------------
  2231 
  2232 * greatly reduced space requirements;
  2233 
  2234 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2235 
  2236 * searchable theorem database (see the section "Retrieving theorems" on
  2237 page 8 of the Reference Manual);
  2238 
  2239 * new examples, including Grabczewski's monumental case study of the
  2240 Axiom of Choice;
  2241 
  2242 * The previous version of HOL renamed to Old_HOL;
  2243 
  2244 * The new version of HOL (previously called CHOL) uses a curried syntax
  2245 for functions.  Application looks like f a b instead of f(a,b);
  2246 
  2247 * Mutually recursive inductive definitions finally work in HOL;
  2248 
  2249 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2250 translates to the operator "split";
  2251 
  2252 
  2253 
  2254 New in Isabelle94-3
  2255 -------------------
  2256 
  2257 * new infix operator, addss, allowing the classical reasoner to
  2258 perform simplification at each step of its search.  Example:
  2259         fast_tac (cs addss ss)
  2260 
  2261 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2262 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2263 look like (a,b) instead of <a,b>;
  2264 
  2265 * PLEASE NOTE: CHOL will eventually replace HOL!
  2266 
  2267 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2268 It translates to the operator "split".  A new theory of integers is available;
  2269 
  2270 * In ZF, integer numerals now denote two's-complement binary integers.
  2271 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2272 
  2273 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2274 of the Axiom of Choice;
  2275 
  2276 
  2277 
  2278 New in Isabelle94-2
  2279 -------------------
  2280 
  2281 * Significantly faster resolution;
  2282 
  2283 * the different sections in a .thy file can now be mixed and repeated
  2284 freely;
  2285 
  2286 * Database of theorems for FOL, HOL and ZF.  New
  2287 commands including qed, qed_goal and bind_thm store theorems in the database.
  2288 
  2289 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2290 a given theory (thms_of), or find out what theory a theorem was proved in
  2291 (theory_of_thm);
  2292 
  2293 * Bugs fixed in the inductive definition and datatype packages;
  2294 
  2295 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2296 and HOL_dup_cs obsolete;
  2297 
  2298 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2299 have been removed;
  2300 
  2301 * Simpler definition of function space in ZF;
  2302 
  2303 * new results about cardinal and ordinal arithmetic in ZF;
  2304 
  2305 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2306 types;
  2307 
  2308 
  2309 $Id$