NEWS
author nipkow
Mon Sep 30 16:50:39 2002 +0200 (2002-09-30)
changeset 13613 531f1f524848
parent 13587 659813a3f879
child 13618 12290bdce807
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: locale specifications now produce predicate definitions
    10 according to the body of text (covering assumptions modulo local
    11 definitions); predicate "loc_axioms" covers newly introduced text,
    12 while "loc" is cumulative wrt. all included locale expressions; the
    13 latter view is presented only on export into the global theory
    14 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    15 on the old view without predicates;
    16 
    17 * Pure: predefined locales "var" and "struct" are useful for sharing
    18 parameters (as in CASL, for example); just specify something like
    19 ``var x + var y + struct M'' as import;
    20 
    21 * Pure: improved thms_containing: proper indexing of facts instead of
    22 raw theorems; check validity of results wrt. current name space;
    23 include local facts of proof configuration (also covers active
    24 locales), cover fixed variables in index; may use "_" in term
    25 specification; an optional limit for the number of printed facts may
    26 be given (the default is 40);
    27 
    28 * Pure: disallow duplicate fact bindings within new-style theory files
    29 (batch-mode only);
    30 
    31 * Provers: improved induct method: assumptions introduced by case
    32 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    33 the goal statement); "foo" still refers to all facts collectively;
    34 
    35 * Provers: the function blast.overloaded has been removed: all constants
    36 are regarded as potentially overloaded, which improves robustness in exchange
    37 for slight decrease in efficiency;
    38 
    39 * Isar: preview of problems to finish 'show' now produce an error
    40 rather than just a warning (in interactive mode);
    41 
    42 
    43 *** HOL ***
    44 
    45 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
    46 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
    47 
    48 * 'typedef' command has new option "open" to suppress the set
    49 definition;
    50 
    51 * functions Min and Max on finite sets have been introduced (theory
    52 Finite_Set);
    53 
    54 * attribute [symmetric] now works for relations as well; it turns
    55 (x,y) : R^-1 into (y,x) : R, and vice versa;
    56 
    57 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    58   In ProofGeneral the counter example appears in the trace buffer.
    59 
    60 * arith(_tac) does now know about div k and mod k where k is a numeral
    61 of type nat or int. It can solve simple goals like
    62 
    63   "0 < n ==> n div 2 < (n::nat)"
    64 
    65 but fails if divisibility plays a role like in
    66 
    67   "n div 2 + (n+1) div 2 = (n::nat)"
    68 
    69 * simp's arithmetic capabilities have been enhanced a bit: it now
    70 takes ~= in premises into account (by performing a case split);
    71 
    72 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
    73 are distributed over a sum of terms;
    74 
    75 * the simplifier trace now shows the names of the applied rewrite rules
    76 
    77 * induct over a !!-quantified statement (say !!x1..xn):
    78   each "case" automatically performs "fix x1 .. xn" with exactly those names.
    79 
    80 * GroupTheory: converted to Isar theories, using locales with implicit structures;
    81 
    82 * Real/HahnBanach: updated and adapted to locales;
    83 
    84 
    85 *** ZF ***
    86 
    87 * ZF/Constructible: consistency proof for AC (Gödel's constructible
    88 universe, etc.);
    89 
    90 * Main ZF: many theories converted to new-style format;
    91 
    92 
    93 *** ML ***
    94 
    95 * Pure: Tactic.prove provides sane interface for internal proofs;
    96 omits the infamous "standard" operation, so this is more appropriate
    97 than prove_goalw_cterm in many situations (e.g. in simprocs);
    98 
    99 * Pure: improved error reporting of simprocs;
   100 
   101 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   102 up simprocs;
   103 
   104 
   105 
   106 New in Isabelle2002 (March 2002)
   107 --------------------------------
   108 
   109 *** Document preparation ***
   110 
   111 * greatly simplified document preparation setup, including more
   112 graceful interpretation of isatool usedir -i/-d/-D options, and more
   113 instructive isatool mkdir; users should basically be able to get
   114 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   115 users may run a separate document processing stage manually like this:
   116 "isatool usedir -D output HOL Test && isatool document Test/output";
   117 
   118 * theory dependency graph may now be incorporated into documents;
   119 isatool usedir -g true will produce session_graph.eps/.pdf for use
   120 with \includegraphics of LaTeX;
   121 
   122 * proper spacing of consecutive markup elements, especially text
   123 blocks after section headings;
   124 
   125 * support bold style (for single symbols only), input syntax is like
   126 this: "\<^bold>\<alpha>" or "\<^bold>A";
   127 
   128 * \<bullet> is now output as bold \cdot by default, which looks much
   129 better in printed text;
   130 
   131 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   132 note that these symbols are currently unavailable in Proof General /
   133 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   134 
   135 * isatool latex no longer depends on changed TEXINPUTS, instead
   136 isatool document copies the Isabelle style files to the target
   137 location;
   138 
   139 
   140 *** Isar ***
   141 
   142 * Pure/Provers: improved proof by cases and induction;
   143   - 'case' command admits impromptu naming of parameters (such as
   144     "case (Suc n)");
   145   - 'induct' method divinates rule instantiation from the inductive
   146     claim; no longer requires excessive ?P bindings for proper
   147     instantiation of cases;
   148   - 'induct' method properly enumerates all possibilities of set/type
   149     rules; as a consequence facts may be also passed through *type*
   150     rules without further ado;
   151   - 'induct' method now derives symbolic cases from the *rulified*
   152     rule (before it used to rulify cases stemming from the internal
   153     atomized version); this means that the context of a non-atomic
   154     statement becomes is included in the hypothesis, avoiding the
   155     slightly cumbersome show "PROP ?case" form;
   156   - 'induct' may now use elim-style induction rules without chaining
   157     facts, using ``missing'' premises from the goal state; this allows
   158     rules stemming from inductive sets to be applied in unstructured
   159     scripts, while still benefitting from proper handling of non-atomic
   160     statements; NB: major inductive premises need to be put first, all
   161     the rest of the goal is passed through the induction;
   162   - 'induct' proper support for mutual induction involving non-atomic
   163     rule statements (uses the new concept of simultaneous goals, see
   164     below);
   165   - append all possible rule selections, but only use the first
   166     success (no backtracking);
   167   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   168   - undeclared rule case names default to numbers 1, 2, 3, ...;
   169   - added 'print_induct_rules' (covered by help item in recent Proof
   170     General versions);
   171   - moved induct/cases attributes to Pure, methods to Provers;
   172   - generic method setup instantiated for FOL and HOL;
   173 
   174 * Pure: support multiple simultaneous goal statements, for example
   175 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   176 meta-level mechanism, this acts as if several individual goals had
   177 been stated separately; in particular common proof methods need to be
   178 repeated in order to cover all claims; note that a single elimination
   179 step is *not* sufficient to establish the two conjunctions, so this
   180 fails:
   181 
   182   assume "A & B" then have A and B ..   (*".." fails*)
   183 
   184 better use "obtain" in situations as above; alternative refer to
   185 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   186 
   187 * Pure: proper integration with ``locales''; unlike the original
   188 version by Florian Kammüller, Isar locales package high-level proof
   189 contexts rather than raw logical ones (e.g. we admit to include
   190 attributes everywhere); operations on locales include merge and
   191 rename; support for implicit arguments (``structures''); simultaneous
   192 type-inference over imports and text; see also HOL/ex/Locales.thy for
   193 some examples;
   194 
   195 * Pure: the following commands have been ``localized'', supporting a
   196 target locale specification "(in name)": 'lemma', 'theorem',
   197 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   198 stored both within the locale and at the theory level (exported and
   199 qualified by the locale name);
   200 
   201 * Pure: theory goals may now be specified in ``long'' form, with
   202 ad-hoc contexts consisting of arbitrary locale elements. for example
   203 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   204 definitions may be given, too); the result is a meta-level rule with
   205 the context elements being discharged in the obvious way;
   206 
   207 * Pure: new proof command 'using' allows to augment currently used
   208 facts after a goal statement ('using' is syntactically analogous to
   209 'apply', but acts on the goal's facts only); this allows chained facts
   210 to be separated into parts given before and after a claim, as in
   211 ``from a and b have C using d and e <proof>'';
   212 
   213 * Pure: renamed "antecedent" case to "rule_context";
   214 
   215 * Pure: new 'judgment' command records explicit information about the
   216 object-logic embedding (used by several tools internally); no longer
   217 use hard-wired "Trueprop";
   218 
   219 * Pure: added 'corollary' command;
   220 
   221 * Pure: fixed 'token_translation' command;
   222 
   223 * Pure: removed obsolete 'exported' attribute;
   224 
   225 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   226 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   227 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   228 
   229 * Pure: method 'atomize' presents local goal premises as object-level
   230 statements (atomic meta-level propositions); setup controlled via
   231 rewrite rules declarations of 'atomize' attribute; example
   232 application: 'induct' method with proper rule statements in improper
   233 proof *scripts*;
   234 
   235 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   236 now consider the syntactic context of assumptions, giving a better
   237 chance to get type-inference of the arguments right (this is
   238 especially important for locales);
   239 
   240 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   241 mode;
   242 
   243 * Pure/obtain: the formal conclusion "thesis", being marked as
   244 ``internal'', may no longer be reference directly in the text;
   245 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   246 situations;
   247 
   248 * Pure: generic 'sym' attribute which declares a rule both as pure
   249 'elim?' and for the 'symmetric' operation;
   250 
   251 * Pure: marginal comments ``--'' may now occur just anywhere in the
   252 text; the fixed correlation with particular command syntax has been
   253 discontinued;
   254 
   255 * Pure: new method 'rules' is particularly well-suited for proof
   256 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   257 but often produces more compact proof terms with less detours;
   258 
   259 * Pure/Provers/classical: simplified integration with pure rule
   260 attributes and methods; the classical "intro?/elim?/dest?"
   261 declarations coincide with the pure ones; the "rule" method no longer
   262 includes classically swapped intros; "intro" and "elim" methods no
   263 longer pick rules from the context; also got rid of ML declarations
   264 AddXIs/AddXEs/AddXDs; all of this has some potential for
   265 INCOMPATIBILITY;
   266 
   267 * Provers/classical: attribute 'swapped' produces classical inversions
   268 of introduction rules;
   269 
   270 * Provers/simplifier: 'simplified' attribute may refer to explicit
   271 rules instead of full simplifier context; 'iff' attribute handles
   272 conditional rules;
   273 
   274 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   275 
   276 * HOL: 'recdef' now fails on unfinished automated proofs, use
   277 "(permissive)" option to recover old behavior;
   278 
   279 * HOL: 'inductive' no longer features separate (collective) attributes
   280 for 'intros' (was found too confusing);
   281 
   282 * HOL: properly declared induction rules less_induct and
   283 wf_induct_rule;
   284 
   285 
   286 *** HOL ***
   287 
   288 * HOL: moved over to sane numeral syntax; the new policy is as
   289 follows:
   290 
   291   - 0 and 1 are polymorphic constants, which are defined on any
   292   numeric type (nat, int, real etc.);
   293 
   294   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   295   binary representation internally;
   296 
   297   - type nat has special constructor Suc, and generally prefers Suc 0
   298   over 1::nat and Suc (Suc 0) over 2::nat;
   299 
   300 This change may cause significant problems of INCOMPATIBILITY; here
   301 are some hints on converting existing sources:
   302 
   303   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   304   entities, so expressions involving "-" (unary or binary minus) need
   305   to be spaced properly;
   306 
   307   - existing occurrences of "1" may need to be constraint "1::nat" or
   308   even replaced by Suc 0; similar for old "2";
   309 
   310   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   311 
   312   - remove all special provisions on numerals in proofs;
   313 
   314 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   315 representation (depends on bin_arith_simps in the default context);
   316 
   317 * HOL: symbolic syntax for x^2 (numeral 2);
   318 
   319 * HOL: the class of all HOL types is now called "type" rather than
   320 "term"; INCOMPATIBILITY, need to adapt references to this type class
   321 in axclass/classes, instance/arities, and (usually rare) occurrences
   322 in typings (of consts etc.); internally the class is called
   323 "HOL.type", ML programs should refer to HOLogic.typeS;
   324 
   325 * HOL/record package improvements:
   326   - new derived operations "fields" to build a partial record section,
   327     "extend" to promote a fixed record to a record scheme, and
   328     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   329     declared as simp by default;
   330   - shared operations ("more", "fields", etc.) now need to be always
   331     qualified) --- potential INCOMPATIBILITY;
   332   - removed "make_scheme" operations (use "make" with "extend") --
   333     INCOMPATIBILITY;
   334   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   335   - provides cases/induct rules for use with corresponding Isar
   336     methods (for concrete records, record schemes, concrete more
   337     parts, and schematic more parts -- in that order);
   338   - internal definitions directly based on a light-weight abstract
   339     theory of product types over typedef rather than datatype;
   340 
   341 * HOL: generic code generator for generating executable ML code from
   342 specifications; specific support for HOL constructs such as inductive
   343 datatypes and sets, as well as recursive functions; can be invoked
   344 via 'generate_code' theory section;
   345 
   346 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   347 
   348 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   349 (beware of argument permutation!);
   350 
   351 * HOL: linorder_less_split superseded by linorder_cases;
   352 
   353 * HOL/List: "nodups" renamed to "distinct";
   354 
   355 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   356 to peripheral theory "Hilbert_Choice";
   357 
   358 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   359 in this (rare) case use:
   360 
   361   delSWrapper "split_all_tac"
   362   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   363 
   364 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   365 MAY FAIL;
   366 
   367 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   368 Isabelle's type classes, ^ on functions and relations has too general
   369 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   370 necessary to attach explicit type constraints;
   371 
   372 * HOL/Relation: the prefix name of the infix "O" has been changed from
   373 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   374 renamed accordingly (eg "compI" -> "rel_compI").
   375 
   376 * HOL: syntax translations now work properly with numerals and records
   377 expressions;
   378 
   379 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   380 of "lam" -- INCOMPATIBILITY;
   381 
   382 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   383 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   384 renamed "Product_Type.unit";
   385 
   386 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   387 
   388 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   389 the "cases" method);
   390 
   391 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   392 Florian Kammüller);
   393 
   394 * HOL/IMP: updated and converted to new-style theory format; several
   395 parts turned into readable document, with proper Isar proof texts and
   396 some explanations (by Gerwin Klein);
   397 
   398 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   399 
   400 * HOL-Hyperreal is now a logic image;
   401 
   402 
   403 *** HOLCF ***
   404 
   405 * Isar: consts/constdefs supports mixfix syntax for continuous
   406 operations;
   407 
   408 * Isar: domain package adapted to new-style theory format, e.g. see
   409 HOLCF/ex/Dnat.thy;
   410 
   411 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   412 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   413 lift.induct_tac, always use UU instead of Undef;
   414 
   415 * HOLCF/IMP: updated and converted to new-style theory;
   416 
   417 
   418 *** ZF ***
   419 
   420 * Isar: proper integration of logic-specific tools and packages,
   421 including theory commands '(co)inductive', '(co)datatype',
   422 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   423 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   424 
   425 * theory Main no longer includes AC; for the Axiom of Choice, base
   426 your theory on Main_ZFC;
   427 
   428 * the integer library now covers quotients and remainders, with many
   429 laws relating division to addition, multiplication, etc.;
   430 
   431 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   432 typeless version of the formalism;
   433 
   434 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   435 format;
   436 
   437 * ZF/Induct: new directory for examples of inductive definitions,
   438 including theory Multiset for multiset orderings; converted to
   439 new-style theory format;
   440 
   441 * ZF: many new theorems about lists, ordinals, etc.;
   442 
   443 
   444 *** General ***
   445 
   446 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   447 variable proof controls level of detail: 0 = no proofs (only oracle
   448 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   449 also ref manual for further ML interfaces;
   450 
   451 * Pure/axclass: removed obsolete ML interface
   452 goal_subclass/goal_arity;
   453 
   454 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   455 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   456 separate tokens, so expressions involving minus need to be spaced
   457 properly;
   458 
   459 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   460 rather than "infixl" or "infixr";
   461 
   462 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   463 sort constraint specifications in type inference; e.g. "x::_::foo"
   464 ensures that the type of "x" is of sort "foo" (but not necessarily a
   465 type variable);
   466 
   467 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   468 control output of nested => (types); the default behavior is
   469 "type_brackets";
   470 
   471 * Pure/syntax: builtin parse translation for "_constify" turns valued
   472 tokens into AST constants;
   473 
   474 * Pure/syntax: prefer later declarations of translations and print
   475 translation functions; potential INCOMPATIBILITY: need to reverse
   476 multiple declarations for same syntax element constant;
   477 
   478 * Pure/show_hyps reset by default (in accordance to existing Isar
   479 practice);
   480 
   481 * Provers/classical: renamed addaltern to addafter, addSaltern to
   482 addSafter;
   483 
   484 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   485 as well;
   486 
   487 * system: tested support for MacOS X; should be able to get Isabelle +
   488 Proof General to work in a plain Terminal after installing Poly/ML
   489 (e.g. from the Isabelle distribution area) and GNU bash alone
   490 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   491 support requires further installations, e.g. from
   492 http://fink.sourceforge.net/);
   493 
   494 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   495 
   496 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   497 of 40 MB), cf. ML_OPTIONS;
   498 
   499 * system: Proof General keywords specification is now part of the
   500 Isabelle distribution (see etc/isar-keywords.el);
   501 
   502 * system: support for persistent Proof General sessions (refrain from
   503 outdating all loaded theories on startup); user may create writable
   504 logic images like this: ``isabelle -q HOL Test'';
   505 
   506 * system: smart selection of Isabelle process versus Isabelle
   507 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   508 run both "isabelle" and "Isabelle" even if file names are badly
   509 damaged (executable inspects the case of the first letter of its own
   510 name); added separate "isabelle-process" and "isabelle-interface";
   511 
   512 * system: refrain from any attempt at filtering input streams; no
   513 longer support ``8bit'' encoding of old isabelle font, instead proper
   514 iso-latin characters may now be used; the related isatools
   515 "symbolinput" and "nonascii" have disappeared as well;
   516 
   517 * system: removed old "xterm" interface (the print modes "xterm" and
   518 "xterm_color" are still available for direct use in a suitable
   519 terminal);
   520 
   521 
   522 
   523 New in Isabelle99-2 (February 2001)
   524 -----------------------------------
   525 
   526 *** Overview of INCOMPATIBILITIES ***
   527 
   528 * HOL: please note that theories in the Library and elsewhere often use the
   529 new-style (Isar) format; to refer to their theorems in an ML script you must
   530 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   531 
   532 * HOL: inductive package no longer splits induction rule aggressively,
   533 but only as far as specified by the introductions given; the old
   534 format may be recovered via ML function complete_split_rule or attribute
   535 'split_rule (complete)';
   536 
   537 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   538 gfp_Tarski to gfp_unfold;
   539 
   540 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   541 
   542 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   543 relation); infix "^^" has been renamed "``"; infix "``" has been
   544 renamed "`"; "univalent" has been renamed "single_valued";
   545 
   546 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   547 operation;
   548 
   549 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   550 
   551 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   552 
   553 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   554 consequence, it is no longer monotonic wrt. the local goal context
   555 (which is now passed through the inductive cases);
   556 
   557 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   558 \<gg> to \<ggreater>;
   559 
   560 
   561 *** Document preparation ***
   562 
   563 * \isabellestyle{NAME} selects version of Isabelle output (currently
   564 available: are "it" for near math-mode best-style output, "sl" for
   565 slanted text style, and "tt" for plain type-writer; if no
   566 \isabellestyle command is given, output is according to slanted
   567 type-writer);
   568 
   569 * support sub/super scripts (for single symbols only), input syntax is
   570 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   571 
   572 * some more standard symbols; see Appendix A of the system manual for
   573 the complete list of symbols defined in isabellesym.sty;
   574 
   575 * improved isabelle style files; more abstract symbol implementation
   576 (should now use \isamath{...} and \isatext{...} in custom symbol
   577 definitions);
   578 
   579 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   580 state; Note that presentation of goal states does not conform to
   581 actual human-readable proof documents.  Please do not include goal
   582 states into document output unless you really know what you are doing!
   583 
   584 * proper indentation of antiquoted output with proportional LaTeX
   585 fonts;
   586 
   587 * no_document ML operator temporarily disables LaTeX document
   588 generation;
   589 
   590 * isatool unsymbolize tunes sources for plain ASCII communication;
   591 
   592 
   593 *** Isar ***
   594 
   595 * Pure: Isar now suffers initial goal statements to contain unbound
   596 schematic variables (this does not conform to actual readable proof
   597 documents, due to unpredictable outcome and non-compositional proof
   598 checking); users who know what they are doing may use schematic goals
   599 for Prolog-style synthesis of proven results;
   600 
   601 * Pure: assumption method (an implicit finishing) now handles actual
   602 rules as well;
   603 
   604 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   605 initial goal, declare "that" only as Pure intro (only for single
   606 steps); the "that" rule assumption may now be involved in implicit
   607 finishing, thus ".." becomes a feasible for trivial obtains;
   608 
   609 * Pure: default proof step now includes 'intro_classes'; thus trivial
   610 instance proofs may be performed by "..";
   611 
   612 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   613 statements as well;
   614 
   615 * Pure: more robust selection of calculational rules;
   616 
   617 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   618 rule (as well as the assumption rule);
   619 
   620 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   621 lemmas, using the graph browser tool;
   622 
   623 * Pure: predict failure of "show" in interactive mode;
   624 
   625 * Pure: 'thms_containing' now takes actual terms as arguments;
   626 
   627 * HOL: improved method 'induct' --- now handles non-atomic goals
   628 (potential INCOMPATIBILITY); tuned error handling;
   629 
   630 * HOL: cases and induct rules now provide explicit hints about the
   631 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   632 any remaining facts are inserted into the goal verbatim;
   633 
   634 * HOL: local contexts (aka cases) may now contain term bindings as
   635 well; the 'cases' and 'induct' methods new provide a ?case binding for
   636 the result to be shown in each case;
   637 
   638 * HOL: added 'recdef_tc' command;
   639 
   640 * isatool convert assists in eliminating legacy ML scripts;
   641 
   642 
   643 *** HOL ***
   644 
   645 * HOL/Library: a collection of generic theories to be used together
   646 with main HOL; the theory loader path already includes this directory
   647 by default; the following existing theories have been moved here:
   648 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   649 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   650 
   651 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   652 modelling and verification task performed in Isabelle/HOL +
   653 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   654 
   655 * HOL/Algebra: special summation operator SUM no longer exists, it has
   656 been replaced by setsum; infix 'assoc' now has priority 50 (like
   657 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   658 'domain', this makes the theory consistent with mathematical
   659 literature;
   660 
   661 * HOL basics: added overloaded operations "inverse" and "divide"
   662 (infix "/"), syntax for generic "abs" operation, generic summation
   663 operator \<Sum>;
   664 
   665 * HOL/typedef: simplified package, provide more useful rules (see also
   666 HOL/subset.thy);
   667 
   668 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   669 now expressed as a proper nested rule (old-style tactic scripts may
   670 require atomize_strip_tac to cope with non-atomic premises);
   671 
   672 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   673 to "split_conv" (old name still available for compatibility);
   674 
   675 * HOL: improved concrete syntax for strings (e.g. allows translation
   676 rules with string literals);
   677 
   678 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   679  and Fleuriot's mechanization of analysis, including the transcendental
   680  functions for the reals;
   681 
   682 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   683 
   684 
   685 *** CTT ***
   686 
   687 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   688 "lam" is displayed as TWO lambda-symbols
   689 
   690 * CTT: theory Main now available, containing everything (that is, Bool
   691 and Arith);
   692 
   693 
   694 *** General ***
   695 
   696 * Pure: the Simplifier has been implemented properly as a derived rule
   697 outside of the actual kernel (at last!); the overall performance
   698 penalty in practical applications is about 50%, while reliability of
   699 the Isabelle inference kernel has been greatly improved;
   700 
   701 * print modes "brackets" and "no_brackets" control output of nested =>
   702 (types) and ==> (props); the default behaviour is "brackets";
   703 
   704 * Provers: fast_tac (and friends) now handle actual object-logic rules
   705 as assumptions as well;
   706 
   707 * system: support Poly/ML 4.0;
   708 
   709 * system: isatool install handles KDE version 1 or 2;
   710 
   711 
   712 
   713 New in Isabelle99-1 (October 2000)
   714 ----------------------------------
   715 
   716 *** Overview of INCOMPATIBILITIES ***
   717 
   718 * HOL: simplification of natural numbers is much changed; to partly
   719 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   720 issue the following ML commands:
   721 
   722   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   723   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   724 
   725 * HOL: simplification no longer dives into case-expressions; this is
   726 controlled by "t.weak_case_cong" for each datatype t;
   727 
   728 * HOL: nat_less_induct renamed to less_induct;
   729 
   730 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   731 fixsome to patch .thy and .ML sources automatically;
   732 
   733   select_equality  -> some_equality
   734   select_eq_Ex     -> some_eq_ex
   735   selectI2EX       -> someI2_ex
   736   selectI2         -> someI2
   737   selectI          -> someI
   738   select1_equality -> some1_equality
   739   Eps_sym_eq       -> some_sym_eq_trivial
   740   Eps_eq           -> some_eq_trivial
   741 
   742 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   743 
   744 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   745 instead);
   746 
   747 * HOL: the recursion equations generated by 'recdef' are now called
   748 f.simps instead of f.rules;
   749 
   750 * HOL: qed_spec_mp now also handles bounded ALL as well;
   751 
   752 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   753 sometimes be needed;
   754 
   755 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   756 
   757 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   758 
   759 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   760 product is now "<*>" instead of "Times"; the lexicographic product is
   761 now "<*lex*>" instead of "**";
   762 
   763 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   764 of main HOL, but was unused); better use HOL's datatype package;
   765 
   766 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   767 the old syntax may be recovered as follows:
   768 
   769   syntax (symbols)
   770     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   771       (infixl "\\<oplus>" 100)
   772 
   773 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   774 
   775 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   776 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   777 internally;
   778 
   779 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   780 changed from A/r to A//r;
   781 
   782 * ZF: new treatment of arithmetic (nat & int) may break some old
   783 proofs;
   784 
   785 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   786 rulify -> rule_format, elimify -> elim_format, ...);
   787 
   788 * Isar/Provers: intro/elim/dest attributes changed; renamed
   789 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   790 should have to change intro!! to intro? only); replaced "delrule" by
   791 "rule del";
   792 
   793 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   794 
   795 * Provers: strengthened force_tac by using new first_best_tac;
   796 
   797 * LaTeX document preparation: several changes of isabelle.sty (see
   798 lib/texinputs);
   799 
   800 
   801 *** Document preparation ***
   802 
   803 * formal comments (text blocks etc.) in new-style theories may now
   804 contain antiquotations of thm/prop/term/typ/text to be presented
   805 according to latex print mode; concrete syntax is like this:
   806 @{term[show_types] "f(x) = a + x"};
   807 
   808 * isatool mkdir provides easy setup of Isabelle session directories,
   809 including proper document sources;
   810 
   811 * generated LaTeX sources are now deleted after successful run
   812 (isatool document -c); may retain a copy somewhere else via -D option
   813 of isatool usedir;
   814 
   815 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   816 style files, achieving self-contained LaTeX sources and simplifying
   817 LaTeX debugging;
   818 
   819 * old-style theories now produce (crude) LaTeX output as well;
   820 
   821 * browser info session directories are now self-contained (may be put
   822 on WWW server seperately); improved graphs of nested sessions; removed
   823 graph for 'all sessions';
   824 
   825 * several improvements in isabelle style files; \isabellestyle{it}
   826 produces fake math mode output; \isamarkupheader is now \section by
   827 default; see lib/texinputs/isabelle.sty etc.;
   828 
   829 
   830 *** Isar ***
   831 
   832 * Isar/Pure: local results and corresponding term bindings are now
   833 subject to Hindley-Milner polymorphism (similar to ML); this
   834 accommodates incremental type-inference very nicely;
   835 
   836 * Isar/Pure: new derived language element 'obtain' supports
   837 generalized existence reasoning;
   838 
   839 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   840 support accumulation of results, without applying any rules yet;
   841 useful to collect intermediate results without explicit name
   842 references, and for use with transitivity rules with more than 2
   843 premises;
   844 
   845 * Isar/Pure: scalable support for case-analysis type proofs: new
   846 'case' language element refers to local contexts symbolically, as
   847 produced by certain proof methods; internally, case names are attached
   848 to theorems as "tags";
   849 
   850 * Isar/Pure: theory command 'hide' removes declarations from
   851 class/type/const name spaces;
   852 
   853 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   854 indicate potential overloading;
   855 
   856 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   857 
   858 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   859 "{a,b,c}" instead of {a,b,c};
   860 
   861 * Isar/Pure now provides its own version of intro/elim/dest
   862 attributes; useful for building new logics, but beware of confusion
   863 with the version in Provers/classical;
   864 
   865 * Isar/Pure: the local context of (non-atomic) goals is provided via
   866 case name 'antecedent';
   867 
   868 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   869 to the current context is now done automatically);
   870 
   871 * Isar/Pure: theory command 'method_setup' provides a simple interface
   872 for definining proof methods in ML;
   873 
   874 * Isar/Provers: intro/elim/dest attributes changed; renamed
   875 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   876 most cases, one should have to change intro!! to intro? only);
   877 replaced "delrule" by "rule del";
   878 
   879 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   880 'symmetric' attribute (the latter supercedes [RS sym]);
   881 
   882 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   883 method modifier); 'simp' method: 'only:' modifier removes loopers as
   884 well (including splits);
   885 
   886 * Isar/Provers: Simplifier and Classical methods now support all kind
   887 of modifiers used in the past, including 'cong', 'iff', etc.
   888 
   889 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   890 of Simplifier and Classical reasoner);
   891 
   892 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   893 now support named cases; major packages (inductive, datatype, primrec,
   894 recdef) support case names and properly name parameters;
   895 
   896 * Isar/HOL: new transitivity rules for substitution in inequalities --
   897 monotonicity conditions are extracted to be proven at end of
   898 calculations;
   899 
   900 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   901 method anyway;
   902 
   903 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   904 split_if split_if_asm; datatype package provides theorems foo.splits =
   905 foo.split foo.split_asm for each datatype;
   906 
   907 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   908 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   909 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   910 use "(cases (simplified))" method in proper proof texts);
   911 
   912 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   913 
   914 * Isar: names of theorems etc. may be natural numbers as well;
   915 
   916 * Isar: 'pr' command: optional arguments for goals_limit and
   917 ProofContext.prems_limit; no longer prints theory contexts, but only
   918 proof states;
   919 
   920 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   921 additional print modes to be specified; e.g. "pr(latex)" will print
   922 proof state according to the Isabelle LaTeX style;
   923 
   924 * Isar: improved support for emulating tactic scripts, including proof
   925 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   926 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   927 (for HOL datatypes);
   928 
   929 * Isar: simplified (more robust) goal selection of proof methods: 1st
   930 goal, all goals, or explicit goal specifier (tactic emulation); thus
   931 'proof method scripts' have to be in depth-first order;
   932 
   933 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   934 
   935 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   936 should instead use individual commands for printing items
   937 (print_commands, print_methods etc.);
   938 
   939 * Isar: added 'nothing' --- the empty list of theorems;
   940 
   941 
   942 *** HOL ***
   943 
   944 * HOL/MicroJava: formalization of a fragment of Java, together with a
   945 corresponding virtual machine and a specification of its bytecode
   946 verifier and a lightweight bytecode verifier, including proofs of
   947 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   948 Cornelia Pusch (see also the homepage of project Bali at
   949 http://isabelle.in.tum.de/Bali/);
   950 
   951 * HOL/Algebra: new theory of rings and univariate polynomials, by
   952 Clemens Ballarin;
   953 
   954 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   955 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   956 Rasmussen;
   957 
   958 * HOL/Lattice: fundamental concepts of lattice theory and order
   959 structures, including duals, properties of bounds versus algebraic
   960 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   961 Theorem for complete lattices etc.; may also serve as a demonstration
   962 for abstract algebraic reasoning using axiomatic type classes, and
   963 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   964 
   965 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   966 von Oheimb;
   967 
   968 * HOL/IMPP: extension of IMP with local variables and mutually
   969 recursive procedures, by David von Oheimb;
   970 
   971 * HOL/Lambda: converted into new-style theory and document;
   972 
   973 * HOL/ex/Multiquote: example of multiple nested quotations and
   974 anti-quotations -- basically a generalized version of de-Bruijn
   975 representation; very useful in avoiding lifting of operations;
   976 
   977 * HOL/record: added general record equality rule to simpset; fixed
   978 select-update simplification procedure to handle extended records as
   979 well; admit "r" as field name;
   980 
   981 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   982 other numeric types and also as the identity of groups, rings, etc.;
   983 
   984 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   985 Types nat and int belong to this axclass;
   986 
   987 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   988    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   989    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   990   two terms #m*u and #n*u are replaced by #(m+n)*u
   991     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   992   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   993     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   994 
   995 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   996 powerful prover for predicate logic but knows nothing of clasets; see
   997 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   998 
   999 * HOL: new version of "case_tac" subsumes both boolean case split and
  1000 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1001 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1002 
  1003 * HOL: simplification no longer dives into case-expressions: only the
  1004 selector expression is simplified, but not the remaining arms; to
  1005 enable full simplification of case-expressions for datatype t, you may
  1006 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1007 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1008 
  1009 * HOL/recdef: the recursion equations generated by 'recdef' for
  1010 function 'f' are now called f.simps instead of f.rules; if all
  1011 termination conditions are proved automatically, these simplification
  1012 rules are added to the simpset, as in primrec; rules may be named
  1013 individually as well, resulting in a separate list of theorems for
  1014 each equation;
  1015 
  1016 * HOL/While is a new theory that provides a while-combinator. It
  1017 permits the definition of tail-recursive functions without the
  1018 provision of a termination measure. The latter is necessary once the
  1019 invariant proof rule for while is applied.
  1020 
  1021 * HOL: new (overloaded) notation for the set of elements below/above
  1022 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1023 
  1024 * HOL: theorems impI, allI, ballI bound as "strip";
  1025 
  1026 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1027 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1028 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1029 
  1030 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1031 
  1032 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1033 main HOL, but was unused);
  1034 
  1035 * HOL: fewer consts declared as global (e.g. have to refer to
  1036 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1037 
  1038 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1039 in case of overlap with user translations (e.g. judgements over
  1040 tuples); (note that the underlying logical represenation is still
  1041 bogus);
  1042 
  1043 
  1044 *** ZF ***
  1045 
  1046 * ZF: simplification automatically cancels common terms in arithmetic
  1047 expressions over nat and int;
  1048 
  1049 * ZF: new treatment of nat to minimize type-checking: all operators
  1050 coerce their operands to a natural number using the function natify,
  1051 making the algebraic laws unconditional;
  1052 
  1053 * ZF: as above, for int: operators coerce their operands to an integer
  1054 using the function intify;
  1055 
  1056 * ZF: the integer library now contains many of the usual laws for the
  1057 orderings, including $<=, and monotonicity laws for $+ and $*;
  1058 
  1059 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1060 simplification;
  1061 
  1062 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1063 to the simplifier and classical reasoner simultaneously;
  1064 
  1065 
  1066 *** General ***
  1067 
  1068 * Provers: blast_tac now handles actual object-logic rules as
  1069 assumptions; note that auto_tac uses blast_tac internally as well;
  1070 
  1071 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1072 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1073 
  1074 * Provers: delrules now handles destruct rules as well (no longer need
  1075 explicit make_elim);
  1076 
  1077 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1078   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1079 use instead the strong form,
  1080   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1081 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1082 from destruct-rules;
  1083 
  1084 * Provers: Simplifier.easy_setup provides a fast path to basic
  1085 Simplifier setup for new object-logics;
  1086 
  1087 * Pure: AST translation rules no longer require constant head on LHS;
  1088 
  1089 * Pure: improved name spaces: ambiguous output is qualified; support
  1090 for hiding of names;
  1091 
  1092 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1093 XSYMBOL_HOME; no longer need to do manual configuration in most
  1094 situations;
  1095 
  1096 * system: compression of ML heaps images may now be controlled via -c
  1097 option of isabelle and isatool usedir (currently only observed by
  1098 Poly/ML);
  1099 
  1100 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1101 useful for remote X11);
  1102 
  1103 * system: provide TAGS file for Isabelle sources;
  1104 
  1105 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1106 order;
  1107 
  1108 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1109 timing flag supersedes proof_timing and Toplevel.trace;
  1110 
  1111 * ML: new combinators |>> and |>>> for incremental transformations
  1112 with secondary results (e.g. certain theory extensions):
  1113 
  1114 * ML: PureThy.add_defs gets additional argument to indicate potential
  1115 overloading (usually false);
  1116 
  1117 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1118 results;
  1119 
  1120 
  1121 
  1122 New in Isabelle99 (October 1999)
  1123 --------------------------------
  1124 
  1125 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1126 
  1127 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1128 are no longer simplified.  (This allows the simplifier to unfold recursive
  1129 functional programs.)  To restore the old behaviour, declare
  1130 
  1131     Delcongs [if_weak_cong];
  1132 
  1133 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1134 complement;
  1135 
  1136 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1137 
  1138 * HOL/datatype: mutual_induct_tac no longer exists --
  1139   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1140 
  1141 * HOL/typedef: fixed type inference for representing set; type
  1142 arguments now have to occur explicitly on the rhs as type constraints;
  1143 
  1144 * ZF: The con_defs part of an inductive definition may no longer refer
  1145 to constants declared in the same theory;
  1146 
  1147 * HOL, ZF: the function mk_cases, generated by the inductive
  1148 definition package, has lost an argument.  To simplify its result, it
  1149 uses the default simpset instead of a supplied list of theorems.
  1150 
  1151 * HOL/List: the constructors of type list are now Nil and Cons;
  1152 
  1153 * Simplifier: the type of the infix ML functions
  1154         setSSolver addSSolver setSolver addSolver
  1155 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1156 for packaging solvers. A solver is created via
  1157         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1158 where the string argument is only a comment.
  1159 
  1160 
  1161 *** Proof tools ***
  1162 
  1163 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1164 decision procedure for linear arithmetic. Currently it is used for
  1165 types `nat', `int', and `real' in HOL (see below); it can, should and
  1166 will be instantiated for other types and logics as well.
  1167 
  1168 * The simplifier now accepts rewrite rules with flexible heads, eg
  1169      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1170   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1171   matching.
  1172 
  1173 
  1174 *** General ***
  1175 
  1176 * New Isabelle/Isar subsystem provides an alternative to traditional
  1177 tactical theorem proving; together with the ProofGeneral/isar user
  1178 interface it offers an interactive environment for developing human
  1179 readable proof documents (Isar == Intelligible semi-automated
  1180 reasoning); for further information see isatool doc isar-ref,
  1181 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1182 
  1183 * improved and simplified presentation of theories: better HTML markup
  1184 (including colors), graph views in several sizes; isatool usedir now
  1185 provides a proper interface for user theories (via -P option); actual
  1186 document preparation based on (PDF)LaTeX is available as well (for
  1187 new-style theories only); see isatool doc system for more information;
  1188 
  1189 * native support for Proof General, both for classic Isabelle and
  1190 Isabelle/Isar;
  1191 
  1192 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1193 using the graph browser tool;
  1194 
  1195 * Isabelle manuals now also available as PDF;
  1196 
  1197 * theory loader rewritten from scratch (may not be fully
  1198 bug-compatible); old loadpath variable has been replaced by show_path,
  1199 add_path, del_path, reset_path functions; new operations such as
  1200 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1201 isatool doc ref);
  1202 
  1203 * improved isatool install: option -k creates KDE application icon,
  1204 option -p DIR installs standalone binaries;
  1205 
  1206 * added ML_PLATFORM setting (useful for cross-platform installations);
  1207 more robust handling of platform specific ML images for SML/NJ;
  1208 
  1209 * the settings environment is now statically scoped, i.e. it is never
  1210 created again in sub-processes invoked from isabelle, isatool, or
  1211 Isabelle;
  1212 
  1213 * path element specification '~~' refers to '$ISABELLE_HOME';
  1214 
  1215 * in locales, the "assumes" and "defines" parts may be omitted if
  1216 empty;
  1217 
  1218 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1219 long arrows);
  1220 
  1221 * new print_mode "HTML";
  1222 
  1223 * new flag show_tags controls display of tags of theorems (which are
  1224 basically just comments that may be attached by some tools);
  1225 
  1226 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1227 mode and goal output format:
  1228 
  1229 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1230 244c244
  1231 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1232 ---
  1233 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1234 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1235 181c181
  1236 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1237 ---
  1238 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1239 
  1240 * function bind_thms stores lists of theorems (cf. bind_thm);
  1241 
  1242 * new shorthand tactics ftac, eatac, datac, fatac;
  1243 
  1244 * qed (and friends) now accept "" as result name; in that case the
  1245 theorem is not stored, but proper checks and presentation of the
  1246 result still apply;
  1247 
  1248 * theorem database now also indexes constants "Trueprop", "all",
  1249 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1250 
  1251 
  1252 *** HOL ***
  1253 
  1254 ** HOL arithmetic **
  1255 
  1256 * There are now decision procedures for linear arithmetic over nat and
  1257 int:
  1258 
  1259 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1260 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1261 are treated as atomic; subformulae not involving type `nat' or `int'
  1262 are ignored; quantified subformulae are ignored unless they are
  1263 positive universal or negative existential. The tactic has to be
  1264 invoked by hand and can be a little bit slow. In particular, the
  1265 running time is exponential in the number of occurrences of `min' and
  1266 `max', and `-' on `nat'.
  1267 
  1268 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1269 (negated) (in)equalities among the premises and the conclusion into
  1270 account (i.e. no compound formulae) and does not know about `min' and
  1271 `max', and `-' on `nat'. It is fast and is used automatically by the
  1272 simplifier.
  1273 
  1274 NB: At the moment, these decision procedures do not cope with mixed
  1275 nat/int formulae where the two parts interact, such as `m < n ==>
  1276 int(m) < int(n)'.
  1277 
  1278 * HOL/Numeral provides a generic theory of numerals (encoded
  1279 efficiently as bit strings); setup for types nat/int/real is in place;
  1280 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1281 int, existing theories and proof scripts may require a few additional
  1282 type constraints;
  1283 
  1284 * integer division and remainder can now be performed on constant
  1285 arguments;
  1286 
  1287 * many properties of integer multiplication, division and remainder
  1288 are now available;
  1289 
  1290 * An interface to the Stanford Validity Checker (SVC) is available through the
  1291 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1292 are proved automatically.  SVC must be installed separately, and its results
  1293 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1294 invocation of the underlying oracle).  For SVC see
  1295   http://verify.stanford.edu/SVC
  1296 
  1297 * IsaMakefile: the HOL-Real target now builds an actual image;
  1298 
  1299 
  1300 ** HOL misc **
  1301 
  1302 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1303 (in Isabelle/Isar) -- by Gertrud Bauer;
  1304 
  1305 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1306 analysis for assembly languages with subtypes;
  1307 
  1308 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1309 -- avoids syntactic ambiguities and treats state, transition, and
  1310 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1311 changed syntax and (many) tactics;
  1312 
  1313 * HOL/inductive: Now also handles more general introduction rules such
  1314   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1315   theorems are now maintained within the theory (maintained via the
  1316   "mono" attribute);
  1317 
  1318 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1319   (using function types) such as
  1320 
  1321   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1322 
  1323 * HOL/record: record_simproc (part of the default simpset) takes care
  1324 of selectors applied to updated records; record_split_tac is no longer
  1325 part of the default claset; update_defs may now be removed from the
  1326 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1327 
  1328   claset_ref () := claset() addSWrapper record_split_wrapper;
  1329   Delsimprocs [record_simproc]
  1330 
  1331 * HOL/typedef: fixed type inference for representing set; type
  1332 arguments now have to occur explicitly on the rhs as type constraints;
  1333 
  1334 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1335 names rather than an ML expression;
  1336 
  1337 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1338 supplied later.  Program schemes can be defined, such as
  1339     "While B C s = (if B s then While B C (C s) else s)"
  1340 where the well-founded relation can be chosen after B and C have been given.
  1341 
  1342 * HOL/List: the constructors of type list are now Nil and Cons;
  1343 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1344 course, ML tools referring to List.list.op # etc. have to be adapted;
  1345 
  1346 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1347 disabled by default; run isabelle with option -m HOL to get back to
  1348 the original Gordon/HOL-style output;
  1349 
  1350 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1351 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1352 
  1353 * HOL basic syntax simplified (more orthogonal): all variants of
  1354 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1355 Eps operator is provided as well: "SOME x. P[x]";
  1356 
  1357 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1358 
  1359 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1360 thus available for user theories;
  1361 
  1362 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1363 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1364 time;
  1365 
  1366 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1367 several times and then mp;
  1368 
  1369 
  1370 *** LK ***
  1371 
  1372 * the notation <<...>> is now available as a notation for sequences of
  1373 formulas;
  1374 
  1375 * the simplifier is now installed
  1376 
  1377 * the axiom system has been generalized (thanks to Soren Heilmann)
  1378 
  1379 * the classical reasoner now has a default rule database
  1380 
  1381 
  1382 *** ZF ***
  1383 
  1384 * new primrec section allows primitive recursive functions to be given
  1385 directly (as in HOL) over datatypes and the natural numbers;
  1386 
  1387 * new tactics induct_tac and exhaust_tac for induction (or case
  1388 analysis) over datatypes and the natural numbers;
  1389 
  1390 * the datatype declaration of type T now defines the recursor T_rec;
  1391 
  1392 * simplification automatically does freeness reasoning for datatype
  1393 constructors;
  1394 
  1395 * automatic type-inference, with AddTCs command to insert new
  1396 type-checking rules;
  1397 
  1398 * datatype introduction rules are now added as Safe Introduction rules
  1399 to the claset;
  1400 
  1401 * the syntax "if P then x else y" is now available in addition to
  1402 if(P,x,y);
  1403 
  1404 
  1405 *** Internal programming interfaces ***
  1406 
  1407 * tuned simplifier trace output; new flag debug_simp;
  1408 
  1409 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1410 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1411 
  1412 * AxClass.axclass_tac lost the theory argument;
  1413 
  1414 * tuned current_goals_markers semantics: begin / end goal avoids
  1415 printing empty lines;
  1416 
  1417 * removed prs and prs_fn hook, which was broken because it did not
  1418 include \n in its semantics, forcing writeln to add one
  1419 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1420 string -> unit if you really want to output text without newline;
  1421 
  1422 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1423 plain output, interface builders may have to enable 'isabelle_font'
  1424 mode to get Isabelle font glyphs as before;
  1425 
  1426 * refined token_translation interface; INCOMPATIBILITY: output length
  1427 now of type real instead of int;
  1428 
  1429 * theory loader actions may be traced via new ThyInfo.add_hook
  1430 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1431 your own database of information attached to *whole* theories -- as
  1432 opposed to intra-theory data slots offered via TheoryDataFun;
  1433 
  1434 * proper handling of dangling sort hypotheses (at last!);
  1435 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1436 extra sort hypotheses that can be witnessed from the type signature;
  1437 the force_strip_shyps flag is gone, any remaining shyps are simply
  1438 left in the theorem (with a warning issued by strip_shyps_warning);
  1439 
  1440 
  1441 
  1442 New in Isabelle98-1 (October 1998)
  1443 ----------------------------------
  1444 
  1445 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1446 
  1447 * several changes of automated proof tools;
  1448 
  1449 * HOL: major changes to the inductive and datatype packages, including
  1450 some minor incompatibilities of theory syntax;
  1451 
  1452 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1453 called `inj_on';
  1454 
  1455 * HOL: removed duplicate thms in Arith:
  1456   less_imp_add_less  should be replaced by  trans_less_add1
  1457   le_imp_add_le      should be replaced by  trans_le_add1
  1458 
  1459 * HOL: unary minus is now overloaded (new type constraints may be
  1460 required);
  1461 
  1462 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1463 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1464 now taken as an integer constant.
  1465 
  1466 * Pure: ML function 'theory_of' renamed to 'theory';
  1467 
  1468 
  1469 *** Proof tools ***
  1470 
  1471 * Simplifier:
  1472   1. Asm_full_simp_tac is now more aggressive.
  1473      1. It will sometimes reorient premises if that increases their power to
  1474         simplify.
  1475      2. It does no longer proceed strictly from left to right but may also
  1476         rotate premises to achieve further simplification.
  1477      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1478      old Asm_full_simp_tac in that it does not rotate premises.
  1479   2. The simplifier now knows a little bit about nat-arithmetic.
  1480 
  1481 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1482 allows for selected deletion of wrappers, by introduction of names for
  1483 wrapper functionals.  This implies that addbefore, addSbefore,
  1484 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1485 and that adding two tactics with the same name overwrites the first
  1486 one (emitting a warning).
  1487   type wrapper = (int -> tactic) -> (int -> tactic)
  1488   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1489   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1490   delWrapper, delSWrapper: claset *  string            -> claset
  1491   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1492 
  1493 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1494 semantics; addbefore now affects only the unsafe part of step_tac
  1495 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1496 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1497 by Force_tac;
  1498 
  1499 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1500 compWrapper; added safe wrapper (and access functions for it);
  1501 
  1502 * HOL/split_all_tac is now much faster and fails if there is nothing
  1503 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1504 and the names of the automatically generated variables have changed.
  1505 split_all_tac has moved within claset() from unsafe wrappers to safe
  1506 wrappers, which means that !!-bound variables are split much more
  1507 aggressively, and safe_tac and clarify_tac now split such variables.
  1508 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1509 Note: the same holds for record_split_tac, which does the job of
  1510 split_all_tac for record fields.
  1511 
  1512 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1513 permanently to the default simpset using Addsplits just like
  1514 Addsimps. They can be removed via Delsplits just like
  1515 Delsimps. Lower-case versions are also available.
  1516 
  1517 * HOL/Simplifier: The rule split_if is now part of the default
  1518 simpset. This means that the simplifier will eliminate all occurrences
  1519 of if-then-else in the conclusion of a goal. To prevent this, you can
  1520 either remove split_if completely from the default simpset by
  1521 `Delsplits [split_if]' or remove it in a specific call of the
  1522 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1523 other case splitting rules to/from the default simpset: every datatype
  1524 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1525 t is the name of the datatype).
  1526 
  1527 * Classical reasoner / Simplifier combination: new force_tac (and
  1528 derivatives Force_tac, force) combines rewriting and classical
  1529 reasoning (and whatever other tools) similarly to auto_tac, but is
  1530 aimed to solve the given subgoal completely.
  1531 
  1532 
  1533 *** General ***
  1534 
  1535 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1536 and `goalw': the theory is no longer needed as an explicit argument -
  1537 the current theory context is used; assumptions are no longer returned
  1538 at the ML-level unless one of them starts with ==> or !!; it is
  1539 recommended to convert to these new commands using isatool fixgoal
  1540 (backup your sources first!);
  1541 
  1542 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1543 the current theory context, and 'theory' to lookup stored theories;
  1544 
  1545 * new theory section 'locale' for declaring constants, assumptions and
  1546 definitions that have local scope;
  1547 
  1548 * new theory section 'nonterminals' for purely syntactic types;
  1549 
  1550 * new theory section 'setup' for generic ML setup functions
  1551 (e.g. package initialization);
  1552 
  1553 * the distribution now includes Isabelle icons: see
  1554 lib/logo/isabelle-{small,tiny}.xpm;
  1555 
  1556 * isatool install - install binaries with absolute references to
  1557 ISABELLE_HOME/bin;
  1558 
  1559 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1560 
  1561 * print mode 'emacs' reserved for Isamode;
  1562 
  1563 * support multiple print (ast) translations per constant name;
  1564 
  1565 * theorems involving oracles are now printed with a suffixed [!];
  1566 
  1567 
  1568 *** HOL ***
  1569 
  1570 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1571 
  1572 * HOL/inductive package reorganized and improved: now supports mutual
  1573 definitions such as
  1574 
  1575   inductive EVEN ODD
  1576     intrs
  1577       null "0 : EVEN"
  1578       oddI "n : EVEN ==> Suc n : ODD"
  1579       evenI "n : ODD ==> Suc n : EVEN"
  1580 
  1581 new theorem list "elims" contains an elimination rule for each of the
  1582 recursive sets; inductive definitions now handle disjunctive premises
  1583 correctly (also ZF);
  1584 
  1585 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1586 "mutual_induct" no longer exists - the induction rule is always
  1587 contained in "induct";
  1588 
  1589 
  1590 * HOL/datatype package re-implemented and greatly improved: now
  1591 supports mutually recursive datatypes such as
  1592 
  1593   datatype
  1594     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1595             | SUM ('a aexp) ('a aexp)
  1596             | DIFF ('a aexp) ('a aexp)
  1597             | NUM 'a
  1598   and
  1599     'a bexp = LESS ('a aexp) ('a aexp)
  1600             | AND ('a bexp) ('a bexp)
  1601             | OR ('a bexp) ('a bexp)
  1602 
  1603 as well as indirectly recursive datatypes such as
  1604 
  1605   datatype
  1606     ('a, 'b) term = Var 'a
  1607                   | App 'b ((('a, 'b) term) list)
  1608 
  1609 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1610 induction on mutually / indirectly recursive datatypes.
  1611 
  1612 Primrec equations are now stored in theory and can be accessed via
  1613 <function_name>.simps.
  1614 
  1615 INCOMPATIBILITIES:
  1616 
  1617   - Theories using datatypes must now have theory Datatype as an
  1618     ancestor.
  1619   - The specific <typename>.induct_tac no longer exists - use the
  1620     generic induct_tac instead.
  1621   - natE has been renamed to nat.exhaust - use exhaust_tac
  1622     instead of res_inst_tac ... natE. Note that the variable
  1623     names in nat.exhaust differ from the names in natE, this
  1624     may cause some "fragile" proofs to fail.
  1625   - The theorems split_<typename>_case and split_<typename>_case_asm
  1626     have been renamed to <typename>.split and <typename>.split_asm.
  1627   - Since default sorts of type variables are now handled correctly,
  1628     some datatype definitions may have to be annotated with explicit
  1629     sort constraints.
  1630   - Primrec definitions no longer require function name and type
  1631     of recursive argument.
  1632 
  1633 Consider using isatool fixdatatype to adapt your theories and proof
  1634 scripts to the new package (backup your sources first!).
  1635 
  1636 
  1637 * HOL/record package: considerably improved implementation; now
  1638 includes concrete syntax for record types, terms, updates; theorems
  1639 for surjective pairing and splitting !!-bound record variables; proof
  1640 support is as follows:
  1641 
  1642   1) standard conversions (selectors or updates applied to record
  1643 constructor terms) are part of the standard simpset;
  1644 
  1645   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1646 made part of standard simpset and claset via addIffs;
  1647 
  1648   3) a tactic for record field splitting (record_split_tac) is part of
  1649 the standard claset (addSWrapper);
  1650 
  1651 To get a better idea about these rules you may retrieve them via
  1652 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1653 the name of your record type.
  1654 
  1655 The split tactic 3) conceptually simplifies by the following rule:
  1656 
  1657   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1658 
  1659 Thus any record variable that is bound by meta-all will automatically
  1660 blow up into some record constructor term, consequently the
  1661 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1662 solve record problems automatically.
  1663 
  1664 
  1665 * reorganized the main HOL image: HOL/Integ and String loaded by
  1666 default; theory Main includes everything;
  1667 
  1668 * automatic simplification of integer sums and comparisons, using cancellation;
  1669 
  1670 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1671 
  1672 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1673 
  1674 * many new identities for unions, intersections, set difference, etc.;
  1675 
  1676 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1677 called split_if, split_split, split_sum_case and split_nat_case (to go
  1678 with add/delsplits);
  1679 
  1680 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1681 (?x::unit) = (); this is made part of the default simpset, which COULD
  1682 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1683 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1684 unit_abs_eta_conv is added in order to counter the effect of
  1685 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1686 %u.f();
  1687 
  1688 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1689 makes more sense);
  1690 
  1691 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1692   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1693   disjointness reasoning but breaking a few old proofs.
  1694 
  1695 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1696 to 'converse' from 'inverse' (for compatibility with ZF and some
  1697 literature);
  1698 
  1699 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1700 the well-founded relation;
  1701 
  1702 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1703     Compl A.  The "Compl" syntax remains available as input syntax for this
  1704     release ONLY.
  1705 
  1706 * HOL/Update: new theory of function updates:
  1707     f(a:=b) == %x. if x=a then b else f x
  1708 may also be iterated as in f(a:=b,c:=d,...);
  1709 
  1710 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1711 
  1712 * HOL/List:
  1713   - new function list_update written xs[i:=v] that updates the i-th
  1714     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1715   - new function `upt' written [i..j(] which generates the list
  1716     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1717     bound write [i..j], which is a shorthand for [i..j+1(].
  1718   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1719 
  1720 * HOL/Arith:
  1721   - removed 'pred' (predecessor) function;
  1722   - generalized some theorems about n-1;
  1723   - many new laws about "div" and "mod";
  1724   - new laws about greatest common divisors (see theory ex/Primes);
  1725 
  1726 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1727 instead of "inverse";
  1728 
  1729 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1730   of the multiset ordering;
  1731 
  1732 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1733   (not included by default);
  1734 
  1735 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1736 
  1737 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1738   programs, i.e. different program variables may have different types.
  1739 
  1740 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1741   [previously, this check worked only if the rewrite rule was unconditional]
  1742   Now rew can involve either definitions or equalities (either == or =).
  1743 
  1744 
  1745 *** ZF ***
  1746 
  1747 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1748   only the theorems proved on ZF.ML;
  1749 
  1750 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1751   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1752   disjointness reasoning but breaking a few old proofs.
  1753 
  1754 * ZF/Update: new theory of function updates
  1755     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1756   may also be iterated as in f(a:=b,c:=d,...);
  1757 
  1758 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1759 
  1760 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1761   [previously, this check worked only if the rewrite rule was unconditional]
  1762   Now rew can involve either definitions or equalities (either == or =).
  1763 
  1764 * case_tac provided for compatibility with HOL
  1765     (like the old excluded_middle_tac, but with subgoals swapped)
  1766 
  1767 
  1768 *** Internal programming interfaces ***
  1769 
  1770 * Pure: several new basic modules made available for general use, see
  1771 also src/Pure/README;
  1772 
  1773 * improved the theory data mechanism to support encapsulation (data
  1774 kind name replaced by private Object.kind, acting as authorization
  1775 key); new type-safe user interface via functor TheoryDataFun; generic
  1776 print_data function becomes basically useless;
  1777 
  1778 * removed global_names compatibility flag -- all theory declarations
  1779 are qualified by default;
  1780 
  1781 * module Pure/Syntax now offers quote / antiquote translation
  1782 functions (useful for Hoare logic etc. with implicit dependencies);
  1783 see HOL/ex/Antiquote for an example use;
  1784 
  1785 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1786 cterm -> thm;
  1787 
  1788 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1789 subgoal;
  1790 
  1791 * Display.print_goals function moved to Locale.print_goals;
  1792 
  1793 * standard print function for goals supports current_goals_markers
  1794 variable for marking begin of proof, end of proof, start of goal; the
  1795 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1796 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1797 for example;
  1798 
  1799 
  1800 
  1801 New in Isabelle98 (January 1998)
  1802 --------------------------------
  1803 
  1804 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1805 
  1806 * changed lexical syntax of terms / types: dots made part of long
  1807 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1808 
  1809 * simpset (and claset) reference variable replaced by functions
  1810 simpset / simpset_ref;
  1811 
  1812 * no longer supports theory aliases (via merge) and non-trivial
  1813 implicit merge of thms' signatures;
  1814 
  1815 * most internal names of constants changed due to qualified names;
  1816 
  1817 * changed Pure/Sequence interface (see Pure/seq.ML);
  1818 
  1819 
  1820 *** General Changes ***
  1821 
  1822 * hierachically structured name spaces (for consts, types, axms, thms
  1823 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1824 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1825 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1826 long_names for fully qualified output names; NOTE: ML programs
  1827 (special tactics, packages etc.) referring to internal names may have
  1828 to be adapted to cope with fully qualified names; in case of severe
  1829 backward campatibility problems try setting 'global_names' at compile
  1830 time to have enrything declared within a flat name space; one may also
  1831 fine tune name declarations in theories via the 'global' and 'local'
  1832 section;
  1833 
  1834 * reimplemented the implicit simpset and claset using the new anytype
  1835 data filed in signatures; references simpset:simpset ref etc. are
  1836 replaced by functions simpset:unit->simpset and
  1837 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1838 to patch your ML files accordingly;
  1839 
  1840 * HTML output now includes theory graph data for display with Java
  1841 applet or isatool browser; data generated automatically via isatool
  1842 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1843 
  1844 * defs may now be conditional; improved rewrite_goals_tac to handle
  1845 conditional equations;
  1846 
  1847 * defs now admits additional type arguments, using TYPE('a) syntax;
  1848 
  1849 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1850 creates a new theory node; implicit merge of thms' signatures is
  1851 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1852 transfer:theory->thm->thm in (rare) cases;
  1853 
  1854 * improved handling of draft signatures / theories; draft thms (and
  1855 ctyps, cterms) are automatically promoted to real ones;
  1856 
  1857 * slightly changed interfaces for oracles: admit many per theory, named
  1858 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1859 
  1860 * print_goals: optional output of const types (set show_consts and
  1861 show_types);
  1862 
  1863 * improved output of warnings (###) and errors (***);
  1864 
  1865 * subgoal_tac displays a warning if the new subgoal has type variables;
  1866 
  1867 * removed old README and Makefiles;
  1868 
  1869 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1870 
  1871 * removed obsolete init_pps and init_database;
  1872 
  1873 * deleted the obsolete tactical STATE, which was declared by
  1874     fun STATE tacfun st = tacfun st st;
  1875 
  1876 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1877 (which abbreviates $HOME);
  1878 
  1879 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1880 use isatool fixseq to adapt your ML programs (this works for fully
  1881 qualified references to the Sequence structure only!);
  1882 
  1883 * use_thy no longer requires writable current directory; it always
  1884 reloads .ML *and* .thy file, if either one is out of date;
  1885 
  1886 
  1887 *** Classical Reasoner ***
  1888 
  1889 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1890 tactics that use classical reasoning to simplify a subgoal without
  1891 splitting it into several subgoals;
  1892 
  1893 * Safe_tac: like safe_tac but uses the default claset;
  1894 
  1895 
  1896 *** Simplifier ***
  1897 
  1898 * added simplification meta rules:
  1899     (asm_)(full_)simplify: simpset -> thm -> thm;
  1900 
  1901 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1902 logics (again);
  1903 
  1904 * added prems argument to simplification procedures;
  1905 
  1906 * HOL, FOL, ZF: added infix function `addsplits':
  1907   instead of `<simpset> setloop (split_tac <thms>)'
  1908   you can simply write `<simpset> addsplits <thms>'
  1909 
  1910 
  1911 *** Syntax ***
  1912 
  1913 * TYPE('a) syntax for type reflection terms;
  1914 
  1915 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1916 
  1917 * pretty printer: changed order of mixfix annotation preference (again!);
  1918 
  1919 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1920 
  1921 
  1922 *** HOL ***
  1923 
  1924 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1925   with `addloop' of the simplifier to faciliate case splitting in premises.
  1926 
  1927 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1928 
  1929 * HOL/Auth: new protocol proofs including some for the Internet
  1930   protocol TLS;
  1931 
  1932 * HOL/Map: new theory of `maps' a la VDM;
  1933 
  1934 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1935 cancelling out common nat summands from =, <, <= (in)equalities, or
  1936 differences; simplification procedures nat_cancel_factor for
  1937 cancelling common factor from =, <, <= (in)equalities over natural
  1938 sums; nat_cancel contains both kinds of procedures, it is installed by
  1939 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1940 
  1941 * HOL/simplifier: terms of the form
  1942   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1943   are rewritten to
  1944   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1945   and those of the form
  1946   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1947   are rewritten to
  1948   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1949 
  1950 * HOL/datatype
  1951   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1952 
  1953   P(t_case f1 ... fn x) =
  1954      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1955         ...
  1956        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1957      )
  1958 
  1959   and a theorem `split_t_case_asm' of the form
  1960 
  1961   P(t_case f1 ... fn x) =
  1962     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1963         ...
  1964        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1965      )
  1966   which can be added to a simpset via `addsplits'. The existing theorems
  1967   expand_list_case and expand_option_case have been renamed to
  1968   split_list_case and split_option_case.
  1969 
  1970 * HOL/Arithmetic:
  1971   - `pred n' is automatically converted to `n-1'.
  1972     Users are strongly encouraged not to use `pred' any longer,
  1973     because it will disappear altogether at some point.
  1974   - Users are strongly encouraged to write "0 < n" rather than
  1975     "n ~= 0". Theorems and proof tools have been modified towards this
  1976     `standard'.
  1977 
  1978 * HOL/Lists:
  1979   the function "set_of_list" has been renamed "set" (and its theorems too);
  1980   the function "nth" now takes its arguments in the reverse order and
  1981   has acquired the infix notation "!" as in "xs!n".
  1982 
  1983 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1984 
  1985 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1986   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1987 
  1988 * HOL/record: extensible records with schematic structural subtyping
  1989 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1990 still lacks various theorems and concrete record syntax;
  1991 
  1992 
  1993 *** HOLCF ***
  1994 
  1995 * removed "axioms" and "generated by" sections;
  1996 
  1997 * replaced "ops" section by extended "consts" section, which is capable of
  1998   handling the continuous function space "->" directly;
  1999 
  2000 * domain package:
  2001   . proves theorems immediately and stores them in the theory,
  2002   . creates hierachical name space,
  2003   . now uses normal mixfix annotations (instead of cinfix...),
  2004   . minor changes to some names and values (for consistency),
  2005   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2006   . separator between mutual domain defs: changed "," to "and",
  2007   . improved handling of sort constraints;  now they have to
  2008     appear on the left-hand side of the equations only;
  2009 
  2010 * fixed LAM <x,y,zs>.b syntax;
  2011 
  2012 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2013 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2014 
  2015 
  2016 *** FOL and ZF ***
  2017 
  2018 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2019   with `addloop' of the simplifier to faciliate case splitting in premises.
  2020 
  2021 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2022 in HOL, they strip ALL and --> from proved theorems;
  2023 
  2024 
  2025 
  2026 New in Isabelle94-8 (May 1997)
  2027 ------------------------------
  2028 
  2029 *** General Changes ***
  2030 
  2031 * new utilities to build / run / maintain Isabelle etc. (in parts
  2032 still somewhat experimental); old Makefiles etc. still functional;
  2033 
  2034 * new 'Isabelle System Manual';
  2035 
  2036 * INSTALL text, together with ./configure and ./build scripts;
  2037 
  2038 * reimplemented type inference for greater efficiency, better error
  2039 messages and clean internal interface;
  2040 
  2041 * prlim command for dealing with lots of subgoals (an easier way of
  2042 setting goals_limit);
  2043 
  2044 
  2045 *** Syntax ***
  2046 
  2047 * supports alternative (named) syntax tables (parser and pretty
  2048 printer); internal interface is provided by add_modesyntax(_i);
  2049 
  2050 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2051 be used in conjunction with the Isabelle symbol font; uses the
  2052 "symbols" syntax table;
  2053 
  2054 * added token_translation interface (may translate name tokens in
  2055 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2056 the current print_mode); IMPORTANT: user print translation functions
  2057 are responsible for marking newly introduced bounds
  2058 (Syntax.mark_boundT);
  2059 
  2060 * token translations for modes "xterm" and "xterm_color" that display
  2061 names in bold, underline etc. or colors (which requires a color
  2062 version of xterm);
  2063 
  2064 * infixes may now be declared with names independent of their syntax;
  2065 
  2066 * added typed_print_translation (like print_translation, but may
  2067 access type of constant);
  2068 
  2069 
  2070 *** Classical Reasoner ***
  2071 
  2072 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2073 some limitations.  Blast_tac...
  2074   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2075   + ignores elimination rules that don't have the correct format
  2076         (the conclusion MUST be a formula variable)
  2077   + ignores types, which can make HOL proofs fail
  2078   + rules must not require higher-order unification, e.g. apply_type in ZF
  2079     [message "Function Var's argument not a bound variable" relates to this]
  2080   + its proof strategy is more general but can actually be slower
  2081 
  2082 * substitution with equality assumptions no longer permutes other
  2083 assumptions;
  2084 
  2085 * minor changes in semantics of addafter (now called addaltern); renamed
  2086 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2087 (and access functions for it);
  2088 
  2089 * improved combination of classical reasoner and simplifier:
  2090   + functions for handling clasimpsets
  2091   + improvement of addss: now the simplifier is called _after_ the
  2092     safe steps.
  2093   + safe variant of addss called addSss: uses safe simplifications
  2094     _during_ the safe steps. It is more complete as it allows multiple
  2095     instantiations of unknowns (e.g. with slow_tac).
  2096 
  2097 *** Simplifier ***
  2098 
  2099 * added interface for simplification procedures (functions that
  2100 produce *proven* rewrite rules on the fly, depending on current
  2101 redex);
  2102 
  2103 * ordering on terms as parameter (used for ordered rewriting);
  2104 
  2105 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2106 
  2107 * the solver is now split into a safe and an unsafe part.
  2108 This should be invisible for the normal user, except that the
  2109 functions setsolver and addsolver have been renamed to setSolver and
  2110 addSolver; added safe_asm_full_simp_tac;
  2111 
  2112 
  2113 *** HOL ***
  2114 
  2115 * a generic induction tactic `induct_tac' which works for all datatypes and
  2116 also for type `nat';
  2117 
  2118 * a generic case distinction tactic `exhaust_tac' which works for all
  2119 datatypes and also for type `nat';
  2120 
  2121 * each datatype comes with a function `size';
  2122 
  2123 * patterns in case expressions allow tuple patterns as arguments to
  2124 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2125 
  2126 * primrec now also works with type nat;
  2127 
  2128 * recdef: a new declaration form, allows general recursive functions to be
  2129 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2130 
  2131 * the constant for negation has been renamed from "not" to "Not" to
  2132 harmonize with FOL, ZF, LK, etc.;
  2133 
  2134 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2135 infinite lists;
  2136 
  2137 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2138 
  2139 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2140 problems in commutative rings, using axiomatic type classes for + and *;
  2141 
  2142 * more examples in HOL/MiniML and HOL/Auth;
  2143 
  2144 * more default rewrite rules for quantifiers, union/intersection;
  2145 
  2146 * a new constant `arbitrary == @x.False';
  2147 
  2148 * HOLCF/IOA replaces old HOL/IOA;
  2149 
  2150 * HOLCF changes: derived all rules and arities
  2151   + axiomatic type classes instead of classes
  2152   + typedef instead of faking type definitions
  2153   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2154   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2155   + eliminated the types void, one, tr
  2156   + use unit lift and bool lift (with translations) instead of one and tr
  2157   + eliminated blift from Lift3.thy (use Def instead of blift)
  2158   all eliminated rules are derived as theorems --> no visible changes ;
  2159 
  2160 
  2161 *** ZF ***
  2162 
  2163 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2164 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2165 as ZF_cs addSIs [equalityI];
  2166 
  2167 
  2168 
  2169 New in Isabelle94-7 (November 96)
  2170 ---------------------------------
  2171 
  2172 * allowing negative levels (as offsets) in prlev and choplev;
  2173 
  2174 * super-linear speedup for large simplifications;
  2175 
  2176 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2177 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2178 FAIL); can suppress it using the command Delsimps (ex_simps @
  2179 all_simps); De Morgan laws are also now included, by default;
  2180 
  2181 * improved printing of ==>  :  ~:
  2182 
  2183 * new object-logic "Sequents" adds linear logic, while replacing LK
  2184 and Modal (thanks to Sara Kalvala);
  2185 
  2186 * HOL/Auth: correctness proofs for authentication protocols;
  2187 
  2188 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2189 examples on HOL/Auth);
  2190 
  2191 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2192 the rewriter and classical reasoner simultaneously;
  2193 
  2194 * function uresult no longer returns theorems in "standard" format;
  2195 regain previous version by: val uresult = standard o uresult;
  2196 
  2197 
  2198 
  2199 New in Isabelle94-6
  2200 -------------------
  2201 
  2202 * oracles -- these establish an interface between Isabelle and trusted
  2203 external reasoners, which may deliver results as theorems;
  2204 
  2205 * proof objects (in particular record all uses of oracles);
  2206 
  2207 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2208 
  2209 * "constdefs" section in theory files;
  2210 
  2211 * "primrec" section (HOL) no longer requires names;
  2212 
  2213 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2214 
  2215 
  2216 
  2217 New in Isabelle94-5
  2218 -------------------
  2219 
  2220 * reduced space requirements;
  2221 
  2222 * automatic HTML generation from theories;
  2223 
  2224 * theory files no longer require "..." (quotes) around most types;
  2225 
  2226 * new examples, including two proofs of the Church-Rosser theorem;
  2227 
  2228 * non-curried (1994) version of HOL is no longer distributed;
  2229 
  2230 
  2231 
  2232 New in Isabelle94-4
  2233 -------------------
  2234 
  2235 * greatly reduced space requirements;
  2236 
  2237 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2238 
  2239 * searchable theorem database (see the section "Retrieving theorems" on
  2240 page 8 of the Reference Manual);
  2241 
  2242 * new examples, including Grabczewski's monumental case study of the
  2243 Axiom of Choice;
  2244 
  2245 * The previous version of HOL renamed to Old_HOL;
  2246 
  2247 * The new version of HOL (previously called CHOL) uses a curried syntax
  2248 for functions.  Application looks like f a b instead of f(a,b);
  2249 
  2250 * Mutually recursive inductive definitions finally work in HOL;
  2251 
  2252 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2253 translates to the operator "split";
  2254 
  2255 
  2256 
  2257 New in Isabelle94-3
  2258 -------------------
  2259 
  2260 * new infix operator, addss, allowing the classical reasoner to
  2261 perform simplification at each step of its search.  Example:
  2262         fast_tac (cs addss ss)
  2263 
  2264 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2265 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2266 look like (a,b) instead of <a,b>;
  2267 
  2268 * PLEASE NOTE: CHOL will eventually replace HOL!
  2269 
  2270 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2271 It translates to the operator "split".  A new theory of integers is available;
  2272 
  2273 * In ZF, integer numerals now denote two's-complement binary integers.
  2274 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2275 
  2276 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2277 of the Axiom of Choice;
  2278 
  2279 
  2280 
  2281 New in Isabelle94-2
  2282 -------------------
  2283 
  2284 * Significantly faster resolution;
  2285 
  2286 * the different sections in a .thy file can now be mixed and repeated
  2287 freely;
  2288 
  2289 * Database of theorems for FOL, HOL and ZF.  New
  2290 commands including qed, qed_goal and bind_thm store theorems in the database.
  2291 
  2292 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2293 a given theory (thms_of), or find out what theory a theorem was proved in
  2294 (theory_of_thm);
  2295 
  2296 * Bugs fixed in the inductive definition and datatype packages;
  2297 
  2298 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2299 and HOL_dup_cs obsolete;
  2300 
  2301 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2302 have been removed;
  2303 
  2304 * Simpler definition of function space in ZF;
  2305 
  2306 * new results about cardinal and ordinal arithmetic in ZF;
  2307 
  2308 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2309 types;
  2310 
  2311 
  2312 $Id$