NEWS
author wenzelm
Thu Aug 29 16:15:11 2002 +0200 (2002-08-29)
changeset 13549 f1522b892a4c
parent 13541 44efea0e21fa
child 13550 5a176b8dda84
permissions -rw-r--r--
updated;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in this Isabelle release
     6 ----------------------------
     7 
     8 *** General ***
     9 
    10 * Pure: locale specifications now produce predicate definitions
    11 according to the body of text (covering assumptions modulo local
    12 definitions); predicate "loc_axioms" covers newly introduced text,
    13 while "loc" is cumulative wrt. all included locale expressions; the
    14 latter view is presented only on export into the global theory
    15 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    16 on the old view without predicates;
    17 
    18 * Pure: predefined locales "var" and "struct" are useful for sharing
    19 parameters (as in CASL, for example); just specify something like
    20 ``var x + var y + struct M'' as import;
    21 
    22 * Pure: improved thms_containing: proper indexing of facts instead of
    23 raw theorems; check validity of results wrt. current name space;
    24 include local facts of proof configuration (also covers active
    25 locales), cover fixed variables in index; may use "_" in term
    26 specification; an optional limit for the number of printed facts may
    27 be given (the default is 40);
    28 
    29 * Pure: disallow duplicate fact bindings within new-style theory files
    30 (batch-mode only);
    31 
    32 * Provers: improved induct method: assumptions introduced by case
    33 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    34 the goal statement); "foo" still refers to all facts collectively;
    35 
    36 * Isar: preview of problems to finish 'show' now produce an error
    37 rather than just a warning (in interactive mode);
    38 
    39 
    40 *** HOL ***
    41 
    42 * 'typedef' command has new option "open" to suppress the set
    43 definition;
    44 
    45 * functions Min and Max on finite sets have been introduced (theory
    46 Finite_Set);
    47 
    48 * attribute [symmetric] now works for relations as well; it turns
    49 (x,y) : R^-1 into (y,x) : R, and vice versa;
    50 
    51 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    52   In ProofGeneral the counter example appears in the trace buffer.
    53 
    54 * arith(_tac) does now know about div k and mod k where k is a numeral
    55 of type nat or int. It can solve simple goals like
    56 
    57   "0 < n ==> n div 2 < (n::nat)"
    58 
    59 but fails if divisibility plays a role like in
    60 
    61   "n div 2 + (n+1) div 2 = (n::nat)"
    62 
    63 * simp's arithmetic capabilities have been enhanced a bit: it now
    64 takes ~= in premises into account (by performing a case split);
    65 
    66 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
    67 are distributed over a sum of terms;
    68 
    69 * Real/HahnBanach: updated and adapted to locales;
    70 
    71 
    72 *** ZF ***
    73 
    74 * ZF/Constructible: consistency proof for AC (Gödel's constructible
    75 universe, etc.);
    76 
    77 * Main ZF: many theories converted to new-style format;
    78 
    79 
    80 *** ML ***
    81 
    82 * Pure: Tactic.prove provides sane interface for internal proofs;
    83 omits the infamous "standard" operation, so this is more appropriate
    84 than prove_goalw_cterm in many situations (e.g. in simprocs);
    85 
    86 * Pure: improved error reporting of simprocs;
    87 
    88 * Provers: Simplifier.simproc(_i) provides sane interface for setting
    89 up simprocs;
    90 
    91 
    92 
    93 New in Isabelle2002 (March 2002)
    94 --------------------------------
    95 
    96 *** Document preparation ***
    97 
    98 * greatly simplified document preparation setup, including more
    99 graceful interpretation of isatool usedir -i/-d/-D options, and more
   100 instructive isatool mkdir; users should basically be able to get
   101 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   102 users may run a separate document processing stage manually like this:
   103 "isatool usedir -D output HOL Test && isatool document Test/output";
   104 
   105 * theory dependency graph may now be incorporated into documents;
   106 isatool usedir -g true will produce session_graph.eps/.pdf for use
   107 with \includegraphics of LaTeX;
   108 
   109 * proper spacing of consecutive markup elements, especially text
   110 blocks after section headings;
   111 
   112 * support bold style (for single symbols only), input syntax is like
   113 this: "\<^bold>\<alpha>" or "\<^bold>A";
   114 
   115 * \<bullet> is now output as bold \cdot by default, which looks much
   116 better in printed text;
   117 
   118 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   119 note that these symbols are currently unavailable in Proof General /
   120 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   121 
   122 * isatool latex no longer depends on changed TEXINPUTS, instead
   123 isatool document copies the Isabelle style files to the target
   124 location;
   125 
   126 
   127 *** Isar ***
   128 
   129 * Pure/Provers: improved proof by cases and induction;
   130   - 'case' command admits impromptu naming of parameters (such as
   131     "case (Suc n)");
   132   - 'induct' method divinates rule instantiation from the inductive
   133     claim; no longer requires excessive ?P bindings for proper
   134     instantiation of cases;
   135   - 'induct' method properly enumerates all possibilities of set/type
   136     rules; as a consequence facts may be also passed through *type*
   137     rules without further ado;
   138   - 'induct' method now derives symbolic cases from the *rulified*
   139     rule (before it used to rulify cases stemming from the internal
   140     atomized version); this means that the context of a non-atomic
   141     statement becomes is included in the hypothesis, avoiding the
   142     slightly cumbersome show "PROP ?case" form;
   143   - 'induct' may now use elim-style induction rules without chaining
   144     facts, using ``missing'' premises from the goal state; this allows
   145     rules stemming from inductive sets to be applied in unstructured
   146     scripts, while still benefitting from proper handling of non-atomic
   147     statements; NB: major inductive premises need to be put first, all
   148     the rest of the goal is passed through the induction;
   149   - 'induct' proper support for mutual induction involving non-atomic
   150     rule statements (uses the new concept of simultaneous goals, see
   151     below);
   152   - append all possible rule selections, but only use the first
   153     success (no backtracking);
   154   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   155   - undeclared rule case names default to numbers 1, 2, 3, ...;
   156   - added 'print_induct_rules' (covered by help item in recent Proof
   157     General versions);
   158   - moved induct/cases attributes to Pure, methods to Provers;
   159   - generic method setup instantiated for FOL and HOL;
   160 
   161 * Pure: support multiple simultaneous goal statements, for example
   162 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   163 meta-level mechanism, this acts as if several individual goals had
   164 been stated separately; in particular common proof methods need to be
   165 repeated in order to cover all claims; note that a single elimination
   166 step is *not* sufficient to establish the two conjunctions, so this
   167 fails:
   168 
   169   assume "A & B" then have A and B ..   (*".." fails*)
   170 
   171 better use "obtain" in situations as above; alternative refer to
   172 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   173 
   174 * Pure: proper integration with ``locales''; unlike the original
   175 version by Florian Kammüller, Isar locales package high-level proof
   176 contexts rather than raw logical ones (e.g. we admit to include
   177 attributes everywhere); operations on locales include merge and
   178 rename; support for implicit arguments (``structures''); simultaneous
   179 type-inference over imports and text; see also HOL/ex/Locales.thy for
   180 some examples;
   181 
   182 * Pure: the following commands have been ``localized'', supporting a
   183 target locale specification "(in name)": 'lemma', 'theorem',
   184 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   185 stored both within the locale and at the theory level (exported and
   186 qualified by the locale name);
   187 
   188 * Pure: theory goals may now be specified in ``long'' form, with
   189 ad-hoc contexts consisting of arbitrary locale elements. for example
   190 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   191 definitions may be given, too); the result is a meta-level rule with
   192 the context elements being discharged in the obvious way;
   193 
   194 * Pure: new proof command 'using' allows to augment currently used
   195 facts after a goal statement ('using' is syntactically analogous to
   196 'apply', but acts on the goal's facts only); this allows chained facts
   197 to be separated into parts given before and after a claim, as in
   198 ``from a and b have C using d and e <proof>'';
   199 
   200 * Pure: renamed "antecedent" case to "rule_context";
   201 
   202 * Pure: new 'judgment' command records explicit information about the
   203 object-logic embedding (used by several tools internally); no longer
   204 use hard-wired "Trueprop";
   205 
   206 * Pure: added 'corollary' command;
   207 
   208 * Pure: fixed 'token_translation' command;
   209 
   210 * Pure: removed obsolete 'exported' attribute;
   211 
   212 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   213 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   214 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   215 
   216 * Pure: method 'atomize' presents local goal premises as object-level
   217 statements (atomic meta-level propositions); setup controlled via
   218 rewrite rules declarations of 'atomize' attribute; example
   219 application: 'induct' method with proper rule statements in improper
   220 proof *scripts*;
   221 
   222 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   223 now consider the syntactic context of assumptions, giving a better
   224 chance to get type-inference of the arguments right (this is
   225 especially important for locales);
   226 
   227 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   228 mode;
   229 
   230 * Pure/obtain: the formal conclusion "thesis", being marked as
   231 ``internal'', may no longer be reference directly in the text;
   232 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   233 situations;
   234 
   235 * Pure: generic 'sym' attribute which declares a rule both as pure
   236 'elim?' and for the 'symmetric' operation;
   237 
   238 * Pure: marginal comments ``--'' may now occur just anywhere in the
   239 text; the fixed correlation with particular command syntax has been
   240 discontinued;
   241 
   242 * Pure: new method 'rules' is particularly well-suited for proof
   243 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   244 but often produces more compact proof terms with less detours;
   245 
   246 * Pure/Provers/classical: simplified integration with pure rule
   247 attributes and methods; the classical "intro?/elim?/dest?"
   248 declarations coincide with the pure ones; the "rule" method no longer
   249 includes classically swapped intros; "intro" and "elim" methods no
   250 longer pick rules from the context; also got rid of ML declarations
   251 AddXIs/AddXEs/AddXDs; all of this has some potential for
   252 INCOMPATIBILITY;
   253 
   254 * Provers/classical: attribute 'swapped' produces classical inversions
   255 of introduction rules;
   256 
   257 * Provers/simplifier: 'simplified' attribute may refer to explicit
   258 rules instead of full simplifier context; 'iff' attribute handles
   259 conditional rules;
   260 
   261 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   262 
   263 * HOL: 'recdef' now fails on unfinished automated proofs, use
   264 "(permissive)" option to recover old behavior;
   265 
   266 * HOL: 'inductive' no longer features separate (collective) attributes
   267 for 'intros' (was found too confusing);
   268 
   269 * HOL: properly declared induction rules less_induct and
   270 wf_induct_rule;
   271 
   272 
   273 *** HOL ***
   274 
   275 * HOL: moved over to sane numeral syntax; the new policy is as
   276 follows:
   277 
   278   - 0 and 1 are polymorphic constants, which are defined on any
   279   numeric type (nat, int, real etc.);
   280 
   281   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   282   binary representation internally;
   283 
   284   - type nat has special constructor Suc, and generally prefers Suc 0
   285   over 1::nat and Suc (Suc 0) over 2::nat;
   286 
   287 This change may cause significant problems of INCOMPATIBILITY; here
   288 are some hints on converting existing sources:
   289 
   290   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   291   entities, so expressions involving "-" (unary or binary minus) need
   292   to be spaced properly;
   293 
   294   - existing occurrences of "1" may need to be constraint "1::nat" or
   295   even replaced by Suc 0; similar for old "2";
   296 
   297   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   298 
   299   - remove all special provisions on numerals in proofs;
   300 
   301 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   302 representation (depends on bin_arith_simps in the default context);
   303 
   304 * HOL: symbolic syntax for x^2 (numeral 2);
   305 
   306 * HOL: the class of all HOL types is now called "type" rather than
   307 "term"; INCOMPATIBILITY, need to adapt references to this type class
   308 in axclass/classes, instance/arities, and (usually rare) occurrences
   309 in typings (of consts etc.); internally the class is called
   310 "HOL.type", ML programs should refer to HOLogic.typeS;
   311 
   312 * HOL/record package improvements:
   313   - new derived operations "fields" to build a partial record section,
   314     "extend" to promote a fixed record to a record scheme, and
   315     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   316     declared as simp by default;
   317   - shared operations ("more", "fields", etc.) now need to be always
   318     qualified) --- potential INCOMPATIBILITY;
   319   - removed "make_scheme" operations (use "make" with "extend") --
   320     INCOMPATIBILITY;
   321   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   322   - provides cases/induct rules for use with corresponding Isar
   323     methods (for concrete records, record schemes, concrete more
   324     parts, and schematic more parts -- in that order);
   325   - internal definitions directly based on a light-weight abstract
   326     theory of product types over typedef rather than datatype;
   327 
   328 * HOL: generic code generator for generating executable ML code from
   329 specifications; specific support for HOL constructs such as inductive
   330 datatypes and sets, as well as recursive functions; can be invoked
   331 via 'generate_code' theory section;
   332 
   333 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   334 
   335 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   336 (beware of argument permutation!);
   337 
   338 * HOL: linorder_less_split superseded by linorder_cases;
   339 
   340 * HOL/List: "nodups" renamed to "distinct";
   341 
   342 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   343 to peripheral theory "Hilbert_Choice";
   344 
   345 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   346 in this (rare) case use:
   347 
   348   delSWrapper "split_all_tac"
   349   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   350 
   351 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   352 MAY FAIL;
   353 
   354 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   355 Isabelle's type classes, ^ on functions and relations has too general
   356 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   357 necessary to attach explicit type constraints;
   358 
   359 * HOL/Relation: the prefix name of the infix "O" has been changed from
   360 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   361 renamed accordingly (eg "compI" -> "rel_compI").
   362 
   363 * HOL: syntax translations now work properly with numerals and records
   364 expressions;
   365 
   366 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   367 of "lam" -- INCOMPATIBILITY;
   368 
   369 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   370 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   371 renamed "Product_Type.unit";
   372 
   373 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   374 
   375 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   376 the "cases" method);
   377 
   378 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   379 Florian Kammüller);
   380 
   381 * HOL/IMP: updated and converted to new-style theory format; several
   382 parts turned into readable document, with proper Isar proof texts and
   383 some explanations (by Gerwin Klein);
   384 
   385 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   386 
   387 * HOL-Hyperreal is now a logic image;
   388 
   389 
   390 *** HOLCF ***
   391 
   392 * Isar: consts/constdefs supports mixfix syntax for continuous
   393 operations;
   394 
   395 * Isar: domain package adapted to new-style theory format, e.g. see
   396 HOLCF/ex/Dnat.thy;
   397 
   398 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   399 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   400 lift.induct_tac, always use UU instead of Undef;
   401 
   402 * HOLCF/IMP: updated and converted to new-style theory;
   403 
   404 
   405 *** ZF ***
   406 
   407 * Isar: proper integration of logic-specific tools and packages,
   408 including theory commands '(co)inductive', '(co)datatype',
   409 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   410 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   411 
   412 * theory Main no longer includes AC; for the Axiom of Choice, base
   413 your theory on Main_ZFC;
   414 
   415 * the integer library now covers quotients and remainders, with many
   416 laws relating division to addition, multiplication, etc.;
   417 
   418 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   419 typeless version of the formalism;
   420 
   421 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   422 format;
   423 
   424 * ZF/Induct: new directory for examples of inductive definitions,
   425 including theory Multiset for multiset orderings; converted to
   426 new-style theory format;
   427 
   428 * ZF: many new theorems about lists, ordinals, etc.;
   429 
   430 
   431 *** General ***
   432 
   433 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   434 variable proof controls level of detail: 0 = no proofs (only oracle
   435 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   436 also ref manual for further ML interfaces;
   437 
   438 * Pure/axclass: removed obsolete ML interface
   439 goal_subclass/goal_arity;
   440 
   441 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   442 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   443 separate tokens, so expressions involving minus need to be spaced
   444 properly;
   445 
   446 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   447 rather than "infixl" or "infixr";
   448 
   449 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   450 sort constraint specifications in type inference; e.g. "x::_::foo"
   451 ensures that the type of "x" is of sort "foo" (but not necessarily a
   452 type variable);
   453 
   454 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   455 control output of nested => (types); the default behavior is
   456 "type_brackets";
   457 
   458 * Pure/syntax: builtin parse translation for "_constify" turns valued
   459 tokens into AST constants;
   460 
   461 * Pure/syntax: prefer later declarations of translations and print
   462 translation functions; potential INCOMPATIBILITY: need to reverse
   463 multiple declarations for same syntax element constant;
   464 
   465 * Pure/show_hyps reset by default (in accordance to existing Isar
   466 practice);
   467 
   468 * Provers/classical: renamed addaltern to addafter, addSaltern to
   469 addSafter;
   470 
   471 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   472 as well;
   473 
   474 * system: tested support for MacOS X; should be able to get Isabelle +
   475 Proof General to work in a plain Terminal after installing Poly/ML
   476 (e.g. from the Isabelle distribution area) and GNU bash alone
   477 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   478 support requires further installations, e.g. from
   479 http://fink.sourceforge.net/);
   480 
   481 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   482 
   483 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   484 of 40 MB), cf. ML_OPTIONS;
   485 
   486 * system: Proof General keywords specification is now part of the
   487 Isabelle distribution (see etc/isar-keywords.el);
   488 
   489 * system: support for persistent Proof General sessions (refrain from
   490 outdating all loaded theories on startup); user may create writable
   491 logic images like this: ``isabelle -q HOL Test'';
   492 
   493 * system: smart selection of Isabelle process versus Isabelle
   494 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   495 run both "isabelle" and "Isabelle" even if file names are badly
   496 damaged (executable inspects the case of the first letter of its own
   497 name); added separate "isabelle-process" and "isabelle-interface";
   498 
   499 * system: refrain from any attempt at filtering input streams; no
   500 longer support ``8bit'' encoding of old isabelle font, instead proper
   501 iso-latin characters may now be used; the related isatools
   502 "symbolinput" and "nonascii" have disappeared as well;
   503 
   504 * system: removed old "xterm" interface (the print modes "xterm" and
   505 "xterm_color" are still available for direct use in a suitable
   506 terminal);
   507 
   508 
   509 
   510 New in Isabelle99-2 (February 2001)
   511 -----------------------------------
   512 
   513 *** Overview of INCOMPATIBILITIES ***
   514 
   515 * HOL: please note that theories in the Library and elsewhere often use the
   516 new-style (Isar) format; to refer to their theorems in an ML script you must
   517 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   518 
   519 * HOL: inductive package no longer splits induction rule aggressively,
   520 but only as far as specified by the introductions given; the old
   521 format may be recovered via ML function complete_split_rule or attribute
   522 'split_rule (complete)';
   523 
   524 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   525 gfp_Tarski to gfp_unfold;
   526 
   527 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   528 
   529 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   530 relation); infix "^^" has been renamed "``"; infix "``" has been
   531 renamed "`"; "univalent" has been renamed "single_valued";
   532 
   533 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   534 operation;
   535 
   536 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   537 
   538 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   539 
   540 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   541 consequence, it is no longer monotonic wrt. the local goal context
   542 (which is now passed through the inductive cases);
   543 
   544 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   545 \<gg> to \<ggreater>;
   546 
   547 
   548 *** Document preparation ***
   549 
   550 * \isabellestyle{NAME} selects version of Isabelle output (currently
   551 available: are "it" for near math-mode best-style output, "sl" for
   552 slanted text style, and "tt" for plain type-writer; if no
   553 \isabellestyle command is given, output is according to slanted
   554 type-writer);
   555 
   556 * support sub/super scripts (for single symbols only), input syntax is
   557 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   558 
   559 * some more standard symbols; see Appendix A of the system manual for
   560 the complete list of symbols defined in isabellesym.sty;
   561 
   562 * improved isabelle style files; more abstract symbol implementation
   563 (should now use \isamath{...} and \isatext{...} in custom symbol
   564 definitions);
   565 
   566 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   567 state; Note that presentation of goal states does not conform to
   568 actual human-readable proof documents.  Please do not include goal
   569 states into document output unless you really know what you are doing!
   570 
   571 * proper indentation of antiquoted output with proportional LaTeX
   572 fonts;
   573 
   574 * no_document ML operator temporarily disables LaTeX document
   575 generation;
   576 
   577 * isatool unsymbolize tunes sources for plain ASCII communication;
   578 
   579 
   580 *** Isar ***
   581 
   582 * Pure: Isar now suffers initial goal statements to contain unbound
   583 schematic variables (this does not conform to actual readable proof
   584 documents, due to unpredictable outcome and non-compositional proof
   585 checking); users who know what they are doing may use schematic goals
   586 for Prolog-style synthesis of proven results;
   587 
   588 * Pure: assumption method (an implicit finishing) now handles actual
   589 rules as well;
   590 
   591 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   592 initial goal, declare "that" only as Pure intro (only for single
   593 steps); the "that" rule assumption may now be involved in implicit
   594 finishing, thus ".." becomes a feasible for trivial obtains;
   595 
   596 * Pure: default proof step now includes 'intro_classes'; thus trivial
   597 instance proofs may be performed by "..";
   598 
   599 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   600 statements as well;
   601 
   602 * Pure: more robust selection of calculational rules;
   603 
   604 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   605 rule (as well as the assumption rule);
   606 
   607 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   608 lemmas, using the graph browser tool;
   609 
   610 * Pure: predict failure of "show" in interactive mode;
   611 
   612 * Pure: 'thms_containing' now takes actual terms as arguments;
   613 
   614 * HOL: improved method 'induct' --- now handles non-atomic goals
   615 (potential INCOMPATIBILITY); tuned error handling;
   616 
   617 * HOL: cases and induct rules now provide explicit hints about the
   618 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   619 any remaining facts are inserted into the goal verbatim;
   620 
   621 * HOL: local contexts (aka cases) may now contain term bindings as
   622 well; the 'cases' and 'induct' methods new provide a ?case binding for
   623 the result to be shown in each case;
   624 
   625 * HOL: added 'recdef_tc' command;
   626 
   627 * isatool convert assists in eliminating legacy ML scripts;
   628 
   629 
   630 *** HOL ***
   631 
   632 * HOL/Library: a collection of generic theories to be used together
   633 with main HOL; the theory loader path already includes this directory
   634 by default; the following existing theories have been moved here:
   635 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   636 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   637 
   638 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   639 modelling and verification task performed in Isabelle/HOL +
   640 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   641 
   642 * HOL/Algebra: special summation operator SUM no longer exists, it has
   643 been replaced by setsum; infix 'assoc' now has priority 50 (like
   644 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   645 'domain', this makes the theory consistent with mathematical
   646 literature;
   647 
   648 * HOL basics: added overloaded operations "inverse" and "divide"
   649 (infix "/"), syntax for generic "abs" operation, generic summation
   650 operator \<Sum>;
   651 
   652 * HOL/typedef: simplified package, provide more useful rules (see also
   653 HOL/subset.thy);
   654 
   655 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   656 now expressed as a proper nested rule (old-style tactic scripts may
   657 require atomize_strip_tac to cope with non-atomic premises);
   658 
   659 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   660 to "split_conv" (old name still available for compatibility);
   661 
   662 * HOL: improved concrete syntax for strings (e.g. allows translation
   663 rules with string literals);
   664 
   665 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   666  and Fleuriot's mechanization of analysis, including the transcendental
   667  functions for the reals;
   668 
   669 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   670 
   671 
   672 *** CTT ***
   673 
   674 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   675 "lam" is displayed as TWO lambda-symbols
   676 
   677 * CTT: theory Main now available, containing everything (that is, Bool
   678 and Arith);
   679 
   680 
   681 *** General ***
   682 
   683 * Pure: the Simplifier has been implemented properly as a derived rule
   684 outside of the actual kernel (at last!); the overall performance
   685 penalty in practical applications is about 50%, while reliability of
   686 the Isabelle inference kernel has been greatly improved;
   687 
   688 * print modes "brackets" and "no_brackets" control output of nested =>
   689 (types) and ==> (props); the default behaviour is "brackets";
   690 
   691 * Provers: fast_tac (and friends) now handle actual object-logic rules
   692 as assumptions as well;
   693 
   694 * system: support Poly/ML 4.0;
   695 
   696 * system: isatool install handles KDE version 1 or 2;
   697 
   698 
   699 
   700 New in Isabelle99-1 (October 2000)
   701 ----------------------------------
   702 
   703 *** Overview of INCOMPATIBILITIES ***
   704 
   705 * HOL: simplification of natural numbers is much changed; to partly
   706 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   707 issue the following ML commands:
   708 
   709   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   710   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   711 
   712 * HOL: simplification no longer dives into case-expressions; this is
   713 controlled by "t.weak_case_cong" for each datatype t;
   714 
   715 * HOL: nat_less_induct renamed to less_induct;
   716 
   717 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   718 fixsome to patch .thy and .ML sources automatically;
   719 
   720   select_equality  -> some_equality
   721   select_eq_Ex     -> some_eq_ex
   722   selectI2EX       -> someI2_ex
   723   selectI2         -> someI2
   724   selectI          -> someI
   725   select1_equality -> some1_equality
   726   Eps_sym_eq       -> some_sym_eq_trivial
   727   Eps_eq           -> some_eq_trivial
   728 
   729 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   730 
   731 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   732 instead);
   733 
   734 * HOL: the recursion equations generated by 'recdef' are now called
   735 f.simps instead of f.rules;
   736 
   737 * HOL: qed_spec_mp now also handles bounded ALL as well;
   738 
   739 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   740 sometimes be needed;
   741 
   742 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   743 
   744 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   745 
   746 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   747 product is now "<*>" instead of "Times"; the lexicographic product is
   748 now "<*lex*>" instead of "**";
   749 
   750 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   751 of main HOL, but was unused); better use HOL's datatype package;
   752 
   753 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   754 the old syntax may be recovered as follows:
   755 
   756   syntax (symbols)
   757     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   758       (infixl "\\<oplus>" 100)
   759 
   760 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   761 
   762 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   763 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   764 internally;
   765 
   766 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   767 changed from A/r to A//r;
   768 
   769 * ZF: new treatment of arithmetic (nat & int) may break some old
   770 proofs;
   771 
   772 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   773 rulify -> rule_format, elimify -> elim_format, ...);
   774 
   775 * Isar/Provers: intro/elim/dest attributes changed; renamed
   776 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   777 should have to change intro!! to intro? only); replaced "delrule" by
   778 "rule del";
   779 
   780 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   781 
   782 * Provers: strengthened force_tac by using new first_best_tac;
   783 
   784 * LaTeX document preparation: several changes of isabelle.sty (see
   785 lib/texinputs);
   786 
   787 
   788 *** Document preparation ***
   789 
   790 * formal comments (text blocks etc.) in new-style theories may now
   791 contain antiquotations of thm/prop/term/typ/text to be presented
   792 according to latex print mode; concrete syntax is like this:
   793 @{term[show_types] "f(x) = a + x"};
   794 
   795 * isatool mkdir provides easy setup of Isabelle session directories,
   796 including proper document sources;
   797 
   798 * generated LaTeX sources are now deleted after successful run
   799 (isatool document -c); may retain a copy somewhere else via -D option
   800 of isatool usedir;
   801 
   802 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   803 style files, achieving self-contained LaTeX sources and simplifying
   804 LaTeX debugging;
   805 
   806 * old-style theories now produce (crude) LaTeX output as well;
   807 
   808 * browser info session directories are now self-contained (may be put
   809 on WWW server seperately); improved graphs of nested sessions; removed
   810 graph for 'all sessions';
   811 
   812 * several improvements in isabelle style files; \isabellestyle{it}
   813 produces fake math mode output; \isamarkupheader is now \section by
   814 default; see lib/texinputs/isabelle.sty etc.;
   815 
   816 
   817 *** Isar ***
   818 
   819 * Isar/Pure: local results and corresponding term bindings are now
   820 subject to Hindley-Milner polymorphism (similar to ML); this
   821 accommodates incremental type-inference very nicely;
   822 
   823 * Isar/Pure: new derived language element 'obtain' supports
   824 generalized existence reasoning;
   825 
   826 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   827 support accumulation of results, without applying any rules yet;
   828 useful to collect intermediate results without explicit name
   829 references, and for use with transitivity rules with more than 2
   830 premises;
   831 
   832 * Isar/Pure: scalable support for case-analysis type proofs: new
   833 'case' language element refers to local contexts symbolically, as
   834 produced by certain proof methods; internally, case names are attached
   835 to theorems as "tags";
   836 
   837 * Isar/Pure: theory command 'hide' removes declarations from
   838 class/type/const name spaces;
   839 
   840 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   841 indicate potential overloading;
   842 
   843 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   844 
   845 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   846 "{a,b,c}" instead of {a,b,c};
   847 
   848 * Isar/Pure now provides its own version of intro/elim/dest
   849 attributes; useful for building new logics, but beware of confusion
   850 with the version in Provers/classical;
   851 
   852 * Isar/Pure: the local context of (non-atomic) goals is provided via
   853 case name 'antecedent';
   854 
   855 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   856 to the current context is now done automatically);
   857 
   858 * Isar/Pure: theory command 'method_setup' provides a simple interface
   859 for definining proof methods in ML;
   860 
   861 * Isar/Provers: intro/elim/dest attributes changed; renamed
   862 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   863 most cases, one should have to change intro!! to intro? only);
   864 replaced "delrule" by "rule del";
   865 
   866 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   867 'symmetric' attribute (the latter supercedes [RS sym]);
   868 
   869 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   870 method modifier); 'simp' method: 'only:' modifier removes loopers as
   871 well (including splits);
   872 
   873 * Isar/Provers: Simplifier and Classical methods now support all kind
   874 of modifiers used in the past, including 'cong', 'iff', etc.
   875 
   876 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   877 of Simplifier and Classical reasoner);
   878 
   879 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   880 now support named cases; major packages (inductive, datatype, primrec,
   881 recdef) support case names and properly name parameters;
   882 
   883 * Isar/HOL: new transitivity rules for substitution in inequalities --
   884 monotonicity conditions are extracted to be proven at end of
   885 calculations;
   886 
   887 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   888 method anyway;
   889 
   890 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   891 split_if split_if_asm; datatype package provides theorems foo.splits =
   892 foo.split foo.split_asm for each datatype;
   893 
   894 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   895 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   896 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   897 use "(cases (simplified))" method in proper proof texts);
   898 
   899 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   900 
   901 * Isar: names of theorems etc. may be natural numbers as well;
   902 
   903 * Isar: 'pr' command: optional arguments for goals_limit and
   904 ProofContext.prems_limit; no longer prints theory contexts, but only
   905 proof states;
   906 
   907 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   908 additional print modes to be specified; e.g. "pr(latex)" will print
   909 proof state according to the Isabelle LaTeX style;
   910 
   911 * Isar: improved support for emulating tactic scripts, including proof
   912 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   913 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   914 (for HOL datatypes);
   915 
   916 * Isar: simplified (more robust) goal selection of proof methods: 1st
   917 goal, all goals, or explicit goal specifier (tactic emulation); thus
   918 'proof method scripts' have to be in depth-first order;
   919 
   920 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   921 
   922 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   923 should instead use individual commands for printing items
   924 (print_commands, print_methods etc.);
   925 
   926 * Isar: added 'nothing' --- the empty list of theorems;
   927 
   928 
   929 *** HOL ***
   930 
   931 * HOL/MicroJava: formalization of a fragment of Java, together with a
   932 corresponding virtual machine and a specification of its bytecode
   933 verifier and a lightweight bytecode verifier, including proofs of
   934 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   935 Cornelia Pusch (see also the homepage of project Bali at
   936 http://isabelle.in.tum.de/Bali/);
   937 
   938 * HOL/Algebra: new theory of rings and univariate polynomials, by
   939 Clemens Ballarin;
   940 
   941 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   942 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   943 Rasmussen;
   944 
   945 * HOL/Lattice: fundamental concepts of lattice theory and order
   946 structures, including duals, properties of bounds versus algebraic
   947 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   948 Theorem for complete lattices etc.; may also serve as a demonstration
   949 for abstract algebraic reasoning using axiomatic type classes, and
   950 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   951 
   952 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   953 von Oheimb;
   954 
   955 * HOL/IMPP: extension of IMP with local variables and mutually
   956 recursive procedures, by David von Oheimb;
   957 
   958 * HOL/Lambda: converted into new-style theory and document;
   959 
   960 * HOL/ex/Multiquote: example of multiple nested quotations and
   961 anti-quotations -- basically a generalized version of de-Bruijn
   962 representation; very useful in avoiding lifting of operations;
   963 
   964 * HOL/record: added general record equality rule to simpset; fixed
   965 select-update simplification procedure to handle extended records as
   966 well; admit "r" as field name;
   967 
   968 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   969 other numeric types and also as the identity of groups, rings, etc.;
   970 
   971 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   972 Types nat and int belong to this axclass;
   973 
   974 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   975    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   976    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   977   two terms #m*u and #n*u are replaced by #(m+n)*u
   978     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   979   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   980     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   981 
   982 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   983 powerful prover for predicate logic but knows nothing of clasets; see
   984 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   985 
   986 * HOL: new version of "case_tac" subsumes both boolean case split and
   987 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   988 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   989 
   990 * HOL: simplification no longer dives into case-expressions: only the
   991 selector expression is simplified, but not the remaining arms; to
   992 enable full simplification of case-expressions for datatype t, you may
   993 remove t.weak_case_cong from the simpset, either globally (Delcongs
   994 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   995 
   996 * HOL/recdef: the recursion equations generated by 'recdef' for
   997 function 'f' are now called f.simps instead of f.rules; if all
   998 termination conditions are proved automatically, these simplification
   999 rules are added to the simpset, as in primrec; rules may be named
  1000 individually as well, resulting in a separate list of theorems for
  1001 each equation;
  1002 
  1003 * HOL/While is a new theory that provides a while-combinator. It
  1004 permits the definition of tail-recursive functions without the
  1005 provision of a termination measure. The latter is necessary once the
  1006 invariant proof rule for while is applied.
  1007 
  1008 * HOL: new (overloaded) notation for the set of elements below/above
  1009 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1010 
  1011 * HOL: theorems impI, allI, ballI bound as "strip";
  1012 
  1013 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1014 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1015 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1016 
  1017 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1018 
  1019 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1020 main HOL, but was unused);
  1021 
  1022 * HOL: fewer consts declared as global (e.g. have to refer to
  1023 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1024 
  1025 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1026 in case of overlap with user translations (e.g. judgements over
  1027 tuples); (note that the underlying logical represenation is still
  1028 bogus);
  1029 
  1030 
  1031 *** ZF ***
  1032 
  1033 * ZF: simplification automatically cancels common terms in arithmetic
  1034 expressions over nat and int;
  1035 
  1036 * ZF: new treatment of nat to minimize type-checking: all operators
  1037 coerce their operands to a natural number using the function natify,
  1038 making the algebraic laws unconditional;
  1039 
  1040 * ZF: as above, for int: operators coerce their operands to an integer
  1041 using the function intify;
  1042 
  1043 * ZF: the integer library now contains many of the usual laws for the
  1044 orderings, including $<=, and monotonicity laws for $+ and $*;
  1045 
  1046 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1047 simplification;
  1048 
  1049 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1050 to the simplifier and classical reasoner simultaneously;
  1051 
  1052 
  1053 *** General ***
  1054 
  1055 * Provers: blast_tac now handles actual object-logic rules as
  1056 assumptions; note that auto_tac uses blast_tac internally as well;
  1057 
  1058 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1059 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1060 
  1061 * Provers: delrules now handles destruct rules as well (no longer need
  1062 explicit make_elim);
  1063 
  1064 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1065   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1066 use instead the strong form,
  1067   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1068 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1069 from destruct-rules;
  1070 
  1071 * Provers: Simplifier.easy_setup provides a fast path to basic
  1072 Simplifier setup for new object-logics;
  1073 
  1074 * Pure: AST translation rules no longer require constant head on LHS;
  1075 
  1076 * Pure: improved name spaces: ambiguous output is qualified; support
  1077 for hiding of names;
  1078 
  1079 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1080 XSYMBOL_HOME; no longer need to do manual configuration in most
  1081 situations;
  1082 
  1083 * system: compression of ML heaps images may now be controlled via -c
  1084 option of isabelle and isatool usedir (currently only observed by
  1085 Poly/ML);
  1086 
  1087 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1088 useful for remote X11);
  1089 
  1090 * system: provide TAGS file for Isabelle sources;
  1091 
  1092 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1093 order;
  1094 
  1095 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1096 timing flag supersedes proof_timing and Toplevel.trace;
  1097 
  1098 * ML: new combinators |>> and |>>> for incremental transformations
  1099 with secondary results (e.g. certain theory extensions):
  1100 
  1101 * ML: PureThy.add_defs gets additional argument to indicate potential
  1102 overloading (usually false);
  1103 
  1104 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1105 results;
  1106 
  1107 
  1108 
  1109 New in Isabelle99 (October 1999)
  1110 --------------------------------
  1111 
  1112 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1113 
  1114 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1115 are no longer simplified.  (This allows the simplifier to unfold recursive
  1116 functional programs.)  To restore the old behaviour, declare
  1117 
  1118     Delcongs [if_weak_cong];
  1119 
  1120 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1121 complement;
  1122 
  1123 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1124 
  1125 * HOL/datatype: mutual_induct_tac no longer exists --
  1126   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1127 
  1128 * HOL/typedef: fixed type inference for representing set; type
  1129 arguments now have to occur explicitly on the rhs as type constraints;
  1130 
  1131 * ZF: The con_defs part of an inductive definition may no longer refer
  1132 to constants declared in the same theory;
  1133 
  1134 * HOL, ZF: the function mk_cases, generated by the inductive
  1135 definition package, has lost an argument.  To simplify its result, it
  1136 uses the default simpset instead of a supplied list of theorems.
  1137 
  1138 * HOL/List: the constructors of type list are now Nil and Cons;
  1139 
  1140 * Simplifier: the type of the infix ML functions
  1141         setSSolver addSSolver setSolver addSolver
  1142 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1143 for packaging solvers. A solver is created via
  1144         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1145 where the string argument is only a comment.
  1146 
  1147 
  1148 *** Proof tools ***
  1149 
  1150 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1151 decision procedure for linear arithmetic. Currently it is used for
  1152 types `nat', `int', and `real' in HOL (see below); it can, should and
  1153 will be instantiated for other types and logics as well.
  1154 
  1155 * The simplifier now accepts rewrite rules with flexible heads, eg
  1156      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1157   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1158   matching.
  1159 
  1160 
  1161 *** General ***
  1162 
  1163 * New Isabelle/Isar subsystem provides an alternative to traditional
  1164 tactical theorem proving; together with the ProofGeneral/isar user
  1165 interface it offers an interactive environment for developing human
  1166 readable proof documents (Isar == Intelligible semi-automated
  1167 reasoning); for further information see isatool doc isar-ref,
  1168 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1169 
  1170 * improved and simplified presentation of theories: better HTML markup
  1171 (including colors), graph views in several sizes; isatool usedir now
  1172 provides a proper interface for user theories (via -P option); actual
  1173 document preparation based on (PDF)LaTeX is available as well (for
  1174 new-style theories only); see isatool doc system for more information;
  1175 
  1176 * native support for Proof General, both for classic Isabelle and
  1177 Isabelle/Isar;
  1178 
  1179 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1180 using the graph browser tool;
  1181 
  1182 * Isabelle manuals now also available as PDF;
  1183 
  1184 * theory loader rewritten from scratch (may not be fully
  1185 bug-compatible); old loadpath variable has been replaced by show_path,
  1186 add_path, del_path, reset_path functions; new operations such as
  1187 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1188 isatool doc ref);
  1189 
  1190 * improved isatool install: option -k creates KDE application icon,
  1191 option -p DIR installs standalone binaries;
  1192 
  1193 * added ML_PLATFORM setting (useful for cross-platform installations);
  1194 more robust handling of platform specific ML images for SML/NJ;
  1195 
  1196 * the settings environment is now statically scoped, i.e. it is never
  1197 created again in sub-processes invoked from isabelle, isatool, or
  1198 Isabelle;
  1199 
  1200 * path element specification '~~' refers to '$ISABELLE_HOME';
  1201 
  1202 * in locales, the "assumes" and "defines" parts may be omitted if
  1203 empty;
  1204 
  1205 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1206 long arrows);
  1207 
  1208 * new print_mode "HTML";
  1209 
  1210 * new flag show_tags controls display of tags of theorems (which are
  1211 basically just comments that may be attached by some tools);
  1212 
  1213 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1214 mode and goal output format:
  1215 
  1216 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1217 244c244
  1218 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1219 ---
  1220 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1221 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1222 181c181
  1223 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1224 ---
  1225 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1226 
  1227 * function bind_thms stores lists of theorems (cf. bind_thm);
  1228 
  1229 * new shorthand tactics ftac, eatac, datac, fatac;
  1230 
  1231 * qed (and friends) now accept "" as result name; in that case the
  1232 theorem is not stored, but proper checks and presentation of the
  1233 result still apply;
  1234 
  1235 * theorem database now also indexes constants "Trueprop", "all",
  1236 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1237 
  1238 
  1239 *** HOL ***
  1240 
  1241 ** HOL arithmetic **
  1242 
  1243 * There are now decision procedures for linear arithmetic over nat and
  1244 int:
  1245 
  1246 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1247 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1248 are treated as atomic; subformulae not involving type `nat' or `int'
  1249 are ignored; quantified subformulae are ignored unless they are
  1250 positive universal or negative existential. The tactic has to be
  1251 invoked by hand and can be a little bit slow. In particular, the
  1252 running time is exponential in the number of occurrences of `min' and
  1253 `max', and `-' on `nat'.
  1254 
  1255 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1256 (negated) (in)equalities among the premises and the conclusion into
  1257 account (i.e. no compound formulae) and does not know about `min' and
  1258 `max', and `-' on `nat'. It is fast and is used automatically by the
  1259 simplifier.
  1260 
  1261 NB: At the moment, these decision procedures do not cope with mixed
  1262 nat/int formulae where the two parts interact, such as `m < n ==>
  1263 int(m) < int(n)'.
  1264 
  1265 * HOL/Numeral provides a generic theory of numerals (encoded
  1266 efficiently as bit strings); setup for types nat/int/real is in place;
  1267 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1268 int, existing theories and proof scripts may require a few additional
  1269 type constraints;
  1270 
  1271 * integer division and remainder can now be performed on constant
  1272 arguments;
  1273 
  1274 * many properties of integer multiplication, division and remainder
  1275 are now available;
  1276 
  1277 * An interface to the Stanford Validity Checker (SVC) is available through the
  1278 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1279 are proved automatically.  SVC must be installed separately, and its results
  1280 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1281 invocation of the underlying oracle).  For SVC see
  1282   http://verify.stanford.edu/SVC
  1283 
  1284 * IsaMakefile: the HOL-Real target now builds an actual image;
  1285 
  1286 
  1287 ** HOL misc **
  1288 
  1289 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1290 (in Isabelle/Isar) -- by Gertrud Bauer;
  1291 
  1292 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1293 analysis for assembly languages with subtypes;
  1294 
  1295 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1296 -- avoids syntactic ambiguities and treats state, transition, and
  1297 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1298 changed syntax and (many) tactics;
  1299 
  1300 * HOL/inductive: Now also handles more general introduction rules such
  1301   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1302   theorems are now maintained within the theory (maintained via the
  1303   "mono" attribute);
  1304 
  1305 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1306   (using function types) such as
  1307 
  1308   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1309 
  1310 * HOL/record: record_simproc (part of the default simpset) takes care
  1311 of selectors applied to updated records; record_split_tac is no longer
  1312 part of the default claset; update_defs may now be removed from the
  1313 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1314 
  1315   claset_ref () := claset() addSWrapper record_split_wrapper;
  1316   Delsimprocs [record_simproc]
  1317 
  1318 * HOL/typedef: fixed type inference for representing set; type
  1319 arguments now have to occur explicitly on the rhs as type constraints;
  1320 
  1321 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1322 names rather than an ML expression;
  1323 
  1324 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1325 supplied later.  Program schemes can be defined, such as
  1326     "While B C s = (if B s then While B C (C s) else s)"
  1327 where the well-founded relation can be chosen after B and C have been given.
  1328 
  1329 * HOL/List: the constructors of type list are now Nil and Cons;
  1330 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1331 course, ML tools referring to List.list.op # etc. have to be adapted;
  1332 
  1333 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1334 disabled by default; run isabelle with option -m HOL to get back to
  1335 the original Gordon/HOL-style output;
  1336 
  1337 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1338 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1339 
  1340 * HOL basic syntax simplified (more orthogonal): all variants of
  1341 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1342 Eps operator is provided as well: "SOME x. P[x]";
  1343 
  1344 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1345 
  1346 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1347 thus available for user theories;
  1348 
  1349 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1350 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1351 time;
  1352 
  1353 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1354 several times and then mp;
  1355 
  1356 
  1357 *** LK ***
  1358 
  1359 * the notation <<...>> is now available as a notation for sequences of
  1360 formulas;
  1361 
  1362 * the simplifier is now installed
  1363 
  1364 * the axiom system has been generalized (thanks to Soren Heilmann)
  1365 
  1366 * the classical reasoner now has a default rule database
  1367 
  1368 
  1369 *** ZF ***
  1370 
  1371 * new primrec section allows primitive recursive functions to be given
  1372 directly (as in HOL) over datatypes and the natural numbers;
  1373 
  1374 * new tactics induct_tac and exhaust_tac for induction (or case
  1375 analysis) over datatypes and the natural numbers;
  1376 
  1377 * the datatype declaration of type T now defines the recursor T_rec;
  1378 
  1379 * simplification automatically does freeness reasoning for datatype
  1380 constructors;
  1381 
  1382 * automatic type-inference, with AddTCs command to insert new
  1383 type-checking rules;
  1384 
  1385 * datatype introduction rules are now added as Safe Introduction rules
  1386 to the claset;
  1387 
  1388 * the syntax "if P then x else y" is now available in addition to
  1389 if(P,x,y);
  1390 
  1391 
  1392 *** Internal programming interfaces ***
  1393 
  1394 * tuned simplifier trace output; new flag debug_simp;
  1395 
  1396 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1397 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1398 
  1399 * AxClass.axclass_tac lost the theory argument;
  1400 
  1401 * tuned current_goals_markers semantics: begin / end goal avoids
  1402 printing empty lines;
  1403 
  1404 * removed prs and prs_fn hook, which was broken because it did not
  1405 include \n in its semantics, forcing writeln to add one
  1406 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1407 string -> unit if you really want to output text without newline;
  1408 
  1409 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1410 plain output, interface builders may have to enable 'isabelle_font'
  1411 mode to get Isabelle font glyphs as before;
  1412 
  1413 * refined token_translation interface; INCOMPATIBILITY: output length
  1414 now of type real instead of int;
  1415 
  1416 * theory loader actions may be traced via new ThyInfo.add_hook
  1417 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1418 your own database of information attached to *whole* theories -- as
  1419 opposed to intra-theory data slots offered via TheoryDataFun;
  1420 
  1421 * proper handling of dangling sort hypotheses (at last!);
  1422 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1423 extra sort hypotheses that can be witnessed from the type signature;
  1424 the force_strip_shyps flag is gone, any remaining shyps are simply
  1425 left in the theorem (with a warning issued by strip_shyps_warning);
  1426 
  1427 
  1428 
  1429 New in Isabelle98-1 (October 1998)
  1430 ----------------------------------
  1431 
  1432 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1433 
  1434 * several changes of automated proof tools;
  1435 
  1436 * HOL: major changes to the inductive and datatype packages, including
  1437 some minor incompatibilities of theory syntax;
  1438 
  1439 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1440 called `inj_on';
  1441 
  1442 * HOL: removed duplicate thms in Arith:
  1443   less_imp_add_less  should be replaced by  trans_less_add1
  1444   le_imp_add_le      should be replaced by  trans_le_add1
  1445 
  1446 * HOL: unary minus is now overloaded (new type constraints may be
  1447 required);
  1448 
  1449 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1450 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1451 now taken as an integer constant.
  1452 
  1453 * Pure: ML function 'theory_of' renamed to 'theory';
  1454 
  1455 
  1456 *** Proof tools ***
  1457 
  1458 * Simplifier:
  1459   1. Asm_full_simp_tac is now more aggressive.
  1460      1. It will sometimes reorient premises if that increases their power to
  1461         simplify.
  1462      2. It does no longer proceed strictly from left to right but may also
  1463         rotate premises to achieve further simplification.
  1464      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1465      old Asm_full_simp_tac in that it does not rotate premises.
  1466   2. The simplifier now knows a little bit about nat-arithmetic.
  1467 
  1468 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1469 allows for selected deletion of wrappers, by introduction of names for
  1470 wrapper functionals.  This implies that addbefore, addSbefore,
  1471 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1472 and that adding two tactics with the same name overwrites the first
  1473 one (emitting a warning).
  1474   type wrapper = (int -> tactic) -> (int -> tactic)
  1475   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1476   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1477   delWrapper, delSWrapper: claset *  string            -> claset
  1478   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1479 
  1480 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1481 semantics; addbefore now affects only the unsafe part of step_tac
  1482 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1483 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1484 by Force_tac;
  1485 
  1486 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1487 compWrapper; added safe wrapper (and access functions for it);
  1488 
  1489 * HOL/split_all_tac is now much faster and fails if there is nothing
  1490 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1491 and the names of the automatically generated variables have changed.
  1492 split_all_tac has moved within claset() from unsafe wrappers to safe
  1493 wrappers, which means that !!-bound variables are split much more
  1494 aggressively, and safe_tac and clarify_tac now split such variables.
  1495 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1496 Note: the same holds for record_split_tac, which does the job of
  1497 split_all_tac for record fields.
  1498 
  1499 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1500 permanently to the default simpset using Addsplits just like
  1501 Addsimps. They can be removed via Delsplits just like
  1502 Delsimps. Lower-case versions are also available.
  1503 
  1504 * HOL/Simplifier: The rule split_if is now part of the default
  1505 simpset. This means that the simplifier will eliminate all occurrences
  1506 of if-then-else in the conclusion of a goal. To prevent this, you can
  1507 either remove split_if completely from the default simpset by
  1508 `Delsplits [split_if]' or remove it in a specific call of the
  1509 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1510 other case splitting rules to/from the default simpset: every datatype
  1511 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1512 t is the name of the datatype).
  1513 
  1514 * Classical reasoner / Simplifier combination: new force_tac (and
  1515 derivatives Force_tac, force) combines rewriting and classical
  1516 reasoning (and whatever other tools) similarly to auto_tac, but is
  1517 aimed to solve the given subgoal completely.
  1518 
  1519 
  1520 *** General ***
  1521 
  1522 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1523 and `goalw': the theory is no longer needed as an explicit argument -
  1524 the current theory context is used; assumptions are no longer returned
  1525 at the ML-level unless one of them starts with ==> or !!; it is
  1526 recommended to convert to these new commands using isatool fixgoal
  1527 (backup your sources first!);
  1528 
  1529 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1530 the current theory context, and 'theory' to lookup stored theories;
  1531 
  1532 * new theory section 'locale' for declaring constants, assumptions and
  1533 definitions that have local scope;
  1534 
  1535 * new theory section 'nonterminals' for purely syntactic types;
  1536 
  1537 * new theory section 'setup' for generic ML setup functions
  1538 (e.g. package initialization);
  1539 
  1540 * the distribution now includes Isabelle icons: see
  1541 lib/logo/isabelle-{small,tiny}.xpm;
  1542 
  1543 * isatool install - install binaries with absolute references to
  1544 ISABELLE_HOME/bin;
  1545 
  1546 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1547 
  1548 * print mode 'emacs' reserved for Isamode;
  1549 
  1550 * support multiple print (ast) translations per constant name;
  1551 
  1552 * theorems involving oracles are now printed with a suffixed [!];
  1553 
  1554 
  1555 *** HOL ***
  1556 
  1557 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1558 
  1559 * HOL/inductive package reorganized and improved: now supports mutual
  1560 definitions such as
  1561 
  1562   inductive EVEN ODD
  1563     intrs
  1564       null "0 : EVEN"
  1565       oddI "n : EVEN ==> Suc n : ODD"
  1566       evenI "n : ODD ==> Suc n : EVEN"
  1567 
  1568 new theorem list "elims" contains an elimination rule for each of the
  1569 recursive sets; inductive definitions now handle disjunctive premises
  1570 correctly (also ZF);
  1571 
  1572 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1573 "mutual_induct" no longer exists - the induction rule is always
  1574 contained in "induct";
  1575 
  1576 
  1577 * HOL/datatype package re-implemented and greatly improved: now
  1578 supports mutually recursive datatypes such as
  1579 
  1580   datatype
  1581     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1582             | SUM ('a aexp) ('a aexp)
  1583             | DIFF ('a aexp) ('a aexp)
  1584             | NUM 'a
  1585   and
  1586     'a bexp = LESS ('a aexp) ('a aexp)
  1587             | AND ('a bexp) ('a bexp)
  1588             | OR ('a bexp) ('a bexp)
  1589 
  1590 as well as indirectly recursive datatypes such as
  1591 
  1592   datatype
  1593     ('a, 'b) term = Var 'a
  1594                   | App 'b ((('a, 'b) term) list)
  1595 
  1596 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1597 induction on mutually / indirectly recursive datatypes.
  1598 
  1599 Primrec equations are now stored in theory and can be accessed via
  1600 <function_name>.simps.
  1601 
  1602 INCOMPATIBILITIES:
  1603 
  1604   - Theories using datatypes must now have theory Datatype as an
  1605     ancestor.
  1606   - The specific <typename>.induct_tac no longer exists - use the
  1607     generic induct_tac instead.
  1608   - natE has been renamed to nat.exhaust - use exhaust_tac
  1609     instead of res_inst_tac ... natE. Note that the variable
  1610     names in nat.exhaust differ from the names in natE, this
  1611     may cause some "fragile" proofs to fail.
  1612   - The theorems split_<typename>_case and split_<typename>_case_asm
  1613     have been renamed to <typename>.split and <typename>.split_asm.
  1614   - Since default sorts of type variables are now handled correctly,
  1615     some datatype definitions may have to be annotated with explicit
  1616     sort constraints.
  1617   - Primrec definitions no longer require function name and type
  1618     of recursive argument.
  1619 
  1620 Consider using isatool fixdatatype to adapt your theories and proof
  1621 scripts to the new package (backup your sources first!).
  1622 
  1623 
  1624 * HOL/record package: considerably improved implementation; now
  1625 includes concrete syntax for record types, terms, updates; theorems
  1626 for surjective pairing and splitting !!-bound record variables; proof
  1627 support is as follows:
  1628 
  1629   1) standard conversions (selectors or updates applied to record
  1630 constructor terms) are part of the standard simpset;
  1631 
  1632   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1633 made part of standard simpset and claset via addIffs;
  1634 
  1635   3) a tactic for record field splitting (record_split_tac) is part of
  1636 the standard claset (addSWrapper);
  1637 
  1638 To get a better idea about these rules you may retrieve them via
  1639 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1640 the name of your record type.
  1641 
  1642 The split tactic 3) conceptually simplifies by the following rule:
  1643 
  1644   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1645 
  1646 Thus any record variable that is bound by meta-all will automatically
  1647 blow up into some record constructor term, consequently the
  1648 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1649 solve record problems automatically.
  1650 
  1651 
  1652 * reorganized the main HOL image: HOL/Integ and String loaded by
  1653 default; theory Main includes everything;
  1654 
  1655 * automatic simplification of integer sums and comparisons, using cancellation;
  1656 
  1657 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1658 
  1659 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1660 
  1661 * many new identities for unions, intersections, set difference, etc.;
  1662 
  1663 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1664 called split_if, split_split, split_sum_case and split_nat_case (to go
  1665 with add/delsplits);
  1666 
  1667 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1668 (?x::unit) = (); this is made part of the default simpset, which COULD
  1669 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1670 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1671 unit_abs_eta_conv is added in order to counter the effect of
  1672 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1673 %u.f();
  1674 
  1675 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1676 makes more sense);
  1677 
  1678 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1679   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1680   disjointness reasoning but breaking a few old proofs.
  1681 
  1682 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1683 to 'converse' from 'inverse' (for compatibility with ZF and some
  1684 literature);
  1685 
  1686 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1687 the well-founded relation;
  1688 
  1689 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1690     Compl A.  The "Compl" syntax remains available as input syntax for this
  1691     release ONLY.
  1692 
  1693 * HOL/Update: new theory of function updates:
  1694     f(a:=b) == %x. if x=a then b else f x
  1695 may also be iterated as in f(a:=b,c:=d,...);
  1696 
  1697 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1698 
  1699 * HOL/List:
  1700   - new function list_update written xs[i:=v] that updates the i-th
  1701     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1702   - new function `upt' written [i..j(] which generates the list
  1703     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1704     bound write [i..j], which is a shorthand for [i..j+1(].
  1705   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1706 
  1707 * HOL/Arith:
  1708   - removed 'pred' (predecessor) function;
  1709   - generalized some theorems about n-1;
  1710   - many new laws about "div" and "mod";
  1711   - new laws about greatest common divisors (see theory ex/Primes);
  1712 
  1713 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1714 instead of "inverse";
  1715 
  1716 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1717   of the multiset ordering;
  1718 
  1719 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1720   (not included by default);
  1721 
  1722 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1723 
  1724 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1725   programs, i.e. different program variables may have different types.
  1726 
  1727 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1728   [previously, this check worked only if the rewrite rule was unconditional]
  1729   Now rew can involve either definitions or equalities (either == or =).
  1730 
  1731 
  1732 *** ZF ***
  1733 
  1734 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1735   only the theorems proved on ZF.ML;
  1736 
  1737 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1738   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1739   disjointness reasoning but breaking a few old proofs.
  1740 
  1741 * ZF/Update: new theory of function updates
  1742     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1743   may also be iterated as in f(a:=b,c:=d,...);
  1744 
  1745 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1746 
  1747 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1748   [previously, this check worked only if the rewrite rule was unconditional]
  1749   Now rew can involve either definitions or equalities (either == or =).
  1750 
  1751 * case_tac provided for compatibility with HOL
  1752     (like the old excluded_middle_tac, but with subgoals swapped)
  1753 
  1754 
  1755 *** Internal programming interfaces ***
  1756 
  1757 * Pure: several new basic modules made available for general use, see
  1758 also src/Pure/README;
  1759 
  1760 * improved the theory data mechanism to support encapsulation (data
  1761 kind name replaced by private Object.kind, acting as authorization
  1762 key); new type-safe user interface via functor TheoryDataFun; generic
  1763 print_data function becomes basically useless;
  1764 
  1765 * removed global_names compatibility flag -- all theory declarations
  1766 are qualified by default;
  1767 
  1768 * module Pure/Syntax now offers quote / antiquote translation
  1769 functions (useful for Hoare logic etc. with implicit dependencies);
  1770 see HOL/ex/Antiquote for an example use;
  1771 
  1772 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1773 cterm -> thm;
  1774 
  1775 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1776 subgoal;
  1777 
  1778 * Display.print_goals function moved to Locale.print_goals;
  1779 
  1780 * standard print function for goals supports current_goals_markers
  1781 variable for marking begin of proof, end of proof, start of goal; the
  1782 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1783 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1784 for example;
  1785 
  1786 
  1787 
  1788 New in Isabelle98 (January 1998)
  1789 --------------------------------
  1790 
  1791 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1792 
  1793 * changed lexical syntax of terms / types: dots made part of long
  1794 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1795 
  1796 * simpset (and claset) reference variable replaced by functions
  1797 simpset / simpset_ref;
  1798 
  1799 * no longer supports theory aliases (via merge) and non-trivial
  1800 implicit merge of thms' signatures;
  1801 
  1802 * most internal names of constants changed due to qualified names;
  1803 
  1804 * changed Pure/Sequence interface (see Pure/seq.ML);
  1805 
  1806 
  1807 *** General Changes ***
  1808 
  1809 * hierachically structured name spaces (for consts, types, axms, thms
  1810 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1811 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1812 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1813 long_names for fully qualified output names; NOTE: ML programs
  1814 (special tactics, packages etc.) referring to internal names may have
  1815 to be adapted to cope with fully qualified names; in case of severe
  1816 backward campatibility problems try setting 'global_names' at compile
  1817 time to have enrything declared within a flat name space; one may also
  1818 fine tune name declarations in theories via the 'global' and 'local'
  1819 section;
  1820 
  1821 * reimplemented the implicit simpset and claset using the new anytype
  1822 data filed in signatures; references simpset:simpset ref etc. are
  1823 replaced by functions simpset:unit->simpset and
  1824 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1825 to patch your ML files accordingly;
  1826 
  1827 * HTML output now includes theory graph data for display with Java
  1828 applet or isatool browser; data generated automatically via isatool
  1829 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1830 
  1831 * defs may now be conditional; improved rewrite_goals_tac to handle
  1832 conditional equations;
  1833 
  1834 * defs now admits additional type arguments, using TYPE('a) syntax;
  1835 
  1836 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1837 creates a new theory node; implicit merge of thms' signatures is
  1838 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1839 transfer:theory->thm->thm in (rare) cases;
  1840 
  1841 * improved handling of draft signatures / theories; draft thms (and
  1842 ctyps, cterms) are automatically promoted to real ones;
  1843 
  1844 * slightly changed interfaces for oracles: admit many per theory, named
  1845 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1846 
  1847 * print_goals: optional output of const types (set show_consts and
  1848 show_types);
  1849 
  1850 * improved output of warnings (###) and errors (***);
  1851 
  1852 * subgoal_tac displays a warning if the new subgoal has type variables;
  1853 
  1854 * removed old README and Makefiles;
  1855 
  1856 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1857 
  1858 * removed obsolete init_pps and init_database;
  1859 
  1860 * deleted the obsolete tactical STATE, which was declared by
  1861     fun STATE tacfun st = tacfun st st;
  1862 
  1863 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1864 (which abbreviates $HOME);
  1865 
  1866 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1867 use isatool fixseq to adapt your ML programs (this works for fully
  1868 qualified references to the Sequence structure only!);
  1869 
  1870 * use_thy no longer requires writable current directory; it always
  1871 reloads .ML *and* .thy file, if either one is out of date;
  1872 
  1873 
  1874 *** Classical Reasoner ***
  1875 
  1876 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1877 tactics that use classical reasoning to simplify a subgoal without
  1878 splitting it into several subgoals;
  1879 
  1880 * Safe_tac: like safe_tac but uses the default claset;
  1881 
  1882 
  1883 *** Simplifier ***
  1884 
  1885 * added simplification meta rules:
  1886     (asm_)(full_)simplify: simpset -> thm -> thm;
  1887 
  1888 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1889 logics (again);
  1890 
  1891 * added prems argument to simplification procedures;
  1892 
  1893 * HOL, FOL, ZF: added infix function `addsplits':
  1894   instead of `<simpset> setloop (split_tac <thms>)'
  1895   you can simply write `<simpset> addsplits <thms>'
  1896 
  1897 
  1898 *** Syntax ***
  1899 
  1900 * TYPE('a) syntax for type reflection terms;
  1901 
  1902 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1903 
  1904 * pretty printer: changed order of mixfix annotation preference (again!);
  1905 
  1906 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1907 
  1908 
  1909 *** HOL ***
  1910 
  1911 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1912   with `addloop' of the simplifier to faciliate case splitting in premises.
  1913 
  1914 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1915 
  1916 * HOL/Auth: new protocol proofs including some for the Internet
  1917   protocol TLS;
  1918 
  1919 * HOL/Map: new theory of `maps' a la VDM;
  1920 
  1921 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1922 cancelling out common nat summands from =, <, <= (in)equalities, or
  1923 differences; simplification procedures nat_cancel_factor for
  1924 cancelling common factor from =, <, <= (in)equalities over natural
  1925 sums; nat_cancel contains both kinds of procedures, it is installed by
  1926 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1927 
  1928 * HOL/simplifier: terms of the form
  1929   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1930   are rewritten to
  1931   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1932   and those of the form
  1933   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1934   are rewritten to
  1935   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1936 
  1937 * HOL/datatype
  1938   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1939 
  1940   P(t_case f1 ... fn x) =
  1941      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1942         ...
  1943        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1944      )
  1945 
  1946   and a theorem `split_t_case_asm' of the form
  1947 
  1948   P(t_case f1 ... fn x) =
  1949     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1950         ...
  1951        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1952      )
  1953   which can be added to a simpset via `addsplits'. The existing theorems
  1954   expand_list_case and expand_option_case have been renamed to
  1955   split_list_case and split_option_case.
  1956 
  1957 * HOL/Arithmetic:
  1958   - `pred n' is automatically converted to `n-1'.
  1959     Users are strongly encouraged not to use `pred' any longer,
  1960     because it will disappear altogether at some point.
  1961   - Users are strongly encouraged to write "0 < n" rather than
  1962     "n ~= 0". Theorems and proof tools have been modified towards this
  1963     `standard'.
  1964 
  1965 * HOL/Lists:
  1966   the function "set_of_list" has been renamed "set" (and its theorems too);
  1967   the function "nth" now takes its arguments in the reverse order and
  1968   has acquired the infix notation "!" as in "xs!n".
  1969 
  1970 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1971 
  1972 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1973   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1974 
  1975 * HOL/record: extensible records with schematic structural subtyping
  1976 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1977 still lacks various theorems and concrete record syntax;
  1978 
  1979 
  1980 *** HOLCF ***
  1981 
  1982 * removed "axioms" and "generated by" sections;
  1983 
  1984 * replaced "ops" section by extended "consts" section, which is capable of
  1985   handling the continuous function space "->" directly;
  1986 
  1987 * domain package:
  1988   . proves theorems immediately and stores them in the theory,
  1989   . creates hierachical name space,
  1990   . now uses normal mixfix annotations (instead of cinfix...),
  1991   . minor changes to some names and values (for consistency),
  1992   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1993   . separator between mutual domain defs: changed "," to "and",
  1994   . improved handling of sort constraints;  now they have to
  1995     appear on the left-hand side of the equations only;
  1996 
  1997 * fixed LAM <x,y,zs>.b syntax;
  1998 
  1999 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2000 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2001 
  2002 
  2003 *** FOL and ZF ***
  2004 
  2005 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2006   with `addloop' of the simplifier to faciliate case splitting in premises.
  2007 
  2008 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2009 in HOL, they strip ALL and --> from proved theorems;
  2010 
  2011 
  2012 
  2013 New in Isabelle94-8 (May 1997)
  2014 ------------------------------
  2015 
  2016 *** General Changes ***
  2017 
  2018 * new utilities to build / run / maintain Isabelle etc. (in parts
  2019 still somewhat experimental); old Makefiles etc. still functional;
  2020 
  2021 * new 'Isabelle System Manual';
  2022 
  2023 * INSTALL text, together with ./configure and ./build scripts;
  2024 
  2025 * reimplemented type inference for greater efficiency, better error
  2026 messages and clean internal interface;
  2027 
  2028 * prlim command for dealing with lots of subgoals (an easier way of
  2029 setting goals_limit);
  2030 
  2031 
  2032 *** Syntax ***
  2033 
  2034 * supports alternative (named) syntax tables (parser and pretty
  2035 printer); internal interface is provided by add_modesyntax(_i);
  2036 
  2037 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2038 be used in conjunction with the Isabelle symbol font; uses the
  2039 "symbols" syntax table;
  2040 
  2041 * added token_translation interface (may translate name tokens in
  2042 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2043 the current print_mode); IMPORTANT: user print translation functions
  2044 are responsible for marking newly introduced bounds
  2045 (Syntax.mark_boundT);
  2046 
  2047 * token translations for modes "xterm" and "xterm_color" that display
  2048 names in bold, underline etc. or colors (which requires a color
  2049 version of xterm);
  2050 
  2051 * infixes may now be declared with names independent of their syntax;
  2052 
  2053 * added typed_print_translation (like print_translation, but may
  2054 access type of constant);
  2055 
  2056 
  2057 *** Classical Reasoner ***
  2058 
  2059 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2060 some limitations.  Blast_tac...
  2061   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2062   + ignores elimination rules that don't have the correct format
  2063         (the conclusion MUST be a formula variable)
  2064   + ignores types, which can make HOL proofs fail
  2065   + rules must not require higher-order unification, e.g. apply_type in ZF
  2066     [message "Function Var's argument not a bound variable" relates to this]
  2067   + its proof strategy is more general but can actually be slower
  2068 
  2069 * substitution with equality assumptions no longer permutes other
  2070 assumptions;
  2071 
  2072 * minor changes in semantics of addafter (now called addaltern); renamed
  2073 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2074 (and access functions for it);
  2075 
  2076 * improved combination of classical reasoner and simplifier:
  2077   + functions for handling clasimpsets
  2078   + improvement of addss: now the simplifier is called _after_ the
  2079     safe steps.
  2080   + safe variant of addss called addSss: uses safe simplifications
  2081     _during_ the safe steps. It is more complete as it allows multiple
  2082     instantiations of unknowns (e.g. with slow_tac).
  2083 
  2084 *** Simplifier ***
  2085 
  2086 * added interface for simplification procedures (functions that
  2087 produce *proven* rewrite rules on the fly, depending on current
  2088 redex);
  2089 
  2090 * ordering on terms as parameter (used for ordered rewriting);
  2091 
  2092 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2093 
  2094 * the solver is now split into a safe and an unsafe part.
  2095 This should be invisible for the normal user, except that the
  2096 functions setsolver and addsolver have been renamed to setSolver and
  2097 addSolver; added safe_asm_full_simp_tac;
  2098 
  2099 
  2100 *** HOL ***
  2101 
  2102 * a generic induction tactic `induct_tac' which works for all datatypes and
  2103 also for type `nat';
  2104 
  2105 * a generic case distinction tactic `exhaust_tac' which works for all
  2106 datatypes and also for type `nat';
  2107 
  2108 * each datatype comes with a function `size';
  2109 
  2110 * patterns in case expressions allow tuple patterns as arguments to
  2111 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2112 
  2113 * primrec now also works with type nat;
  2114 
  2115 * recdef: a new declaration form, allows general recursive functions to be
  2116 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2117 
  2118 * the constant for negation has been renamed from "not" to "Not" to
  2119 harmonize with FOL, ZF, LK, etc.;
  2120 
  2121 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2122 infinite lists;
  2123 
  2124 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2125 
  2126 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2127 problems in commutative rings, using axiomatic type classes for + and *;
  2128 
  2129 * more examples in HOL/MiniML and HOL/Auth;
  2130 
  2131 * more default rewrite rules for quantifiers, union/intersection;
  2132 
  2133 * a new constant `arbitrary == @x.False';
  2134 
  2135 * HOLCF/IOA replaces old HOL/IOA;
  2136 
  2137 * HOLCF changes: derived all rules and arities
  2138   + axiomatic type classes instead of classes
  2139   + typedef instead of faking type definitions
  2140   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2141   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2142   + eliminated the types void, one, tr
  2143   + use unit lift and bool lift (with translations) instead of one and tr
  2144   + eliminated blift from Lift3.thy (use Def instead of blift)
  2145   all eliminated rules are derived as theorems --> no visible changes ;
  2146 
  2147 
  2148 *** ZF ***
  2149 
  2150 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2151 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2152 as ZF_cs addSIs [equalityI];
  2153 
  2154 
  2155 
  2156 New in Isabelle94-7 (November 96)
  2157 ---------------------------------
  2158 
  2159 * allowing negative levels (as offsets) in prlev and choplev;
  2160 
  2161 * super-linear speedup for large simplifications;
  2162 
  2163 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2164 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2165 FAIL); can suppress it using the command Delsimps (ex_simps @
  2166 all_simps); De Morgan laws are also now included, by default;
  2167 
  2168 * improved printing of ==>  :  ~:
  2169 
  2170 * new object-logic "Sequents" adds linear logic, while replacing LK
  2171 and Modal (thanks to Sara Kalvala);
  2172 
  2173 * HOL/Auth: correctness proofs for authentication protocols;
  2174 
  2175 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2176 examples on HOL/Auth);
  2177 
  2178 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2179 the rewriter and classical reasoner simultaneously;
  2180 
  2181 * function uresult no longer returns theorems in "standard" format;
  2182 regain previous version by: val uresult = standard o uresult;
  2183 
  2184 
  2185 
  2186 New in Isabelle94-6
  2187 -------------------
  2188 
  2189 * oracles -- these establish an interface between Isabelle and trusted
  2190 external reasoners, which may deliver results as theorems;
  2191 
  2192 * proof objects (in particular record all uses of oracles);
  2193 
  2194 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2195 
  2196 * "constdefs" section in theory files;
  2197 
  2198 * "primrec" section (HOL) no longer requires names;
  2199 
  2200 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2201 
  2202 
  2203 
  2204 New in Isabelle94-5
  2205 -------------------
  2206 
  2207 * reduced space requirements;
  2208 
  2209 * automatic HTML generation from theories;
  2210 
  2211 * theory files no longer require "..." (quotes) around most types;
  2212 
  2213 * new examples, including two proofs of the Church-Rosser theorem;
  2214 
  2215 * non-curried (1994) version of HOL is no longer distributed;
  2216 
  2217 
  2218 
  2219 New in Isabelle94-4
  2220 -------------------
  2221 
  2222 * greatly reduced space requirements;
  2223 
  2224 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2225 
  2226 * searchable theorem database (see the section "Retrieving theorems" on
  2227 page 8 of the Reference Manual);
  2228 
  2229 * new examples, including Grabczewski's monumental case study of the
  2230 Axiom of Choice;
  2231 
  2232 * The previous version of HOL renamed to Old_HOL;
  2233 
  2234 * The new version of HOL (previously called CHOL) uses a curried syntax
  2235 for functions.  Application looks like f a b instead of f(a,b);
  2236 
  2237 * Mutually recursive inductive definitions finally work in HOL;
  2238 
  2239 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2240 translates to the operator "split";
  2241 
  2242 
  2243 
  2244 New in Isabelle94-3
  2245 -------------------
  2246 
  2247 * new infix operator, addss, allowing the classical reasoner to
  2248 perform simplification at each step of its search.  Example:
  2249         fast_tac (cs addss ss)
  2250 
  2251 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2252 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2253 look like (a,b) instead of <a,b>;
  2254 
  2255 * PLEASE NOTE: CHOL will eventually replace HOL!
  2256 
  2257 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2258 It translates to the operator "split".  A new theory of integers is available;
  2259 
  2260 * In ZF, integer numerals now denote two's-complement binary integers.
  2261 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2262 
  2263 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2264 of the Axiom of Choice;
  2265 
  2266 
  2267 
  2268 New in Isabelle94-2
  2269 -------------------
  2270 
  2271 * Significantly faster resolution;
  2272 
  2273 * the different sections in a .thy file can now be mixed and repeated
  2274 freely;
  2275 
  2276 * Database of theorems for FOL, HOL and ZF.  New
  2277 commands including qed, qed_goal and bind_thm store theorems in the database.
  2278 
  2279 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2280 a given theory (thms_of), or find out what theory a theorem was proved in
  2281 (theory_of_thm);
  2282 
  2283 * Bugs fixed in the inductive definition and datatype packages;
  2284 
  2285 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2286 and HOL_dup_cs obsolete;
  2287 
  2288 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2289 have been removed;
  2290 
  2291 * Simpler definition of function space in ZF;
  2292 
  2293 * new results about cardinal and ordinal arithmetic in ZF;
  2294 
  2295 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2296 types;
  2297 
  2298 
  2299 $Id$