NEWS
author paulson
Fri Aug 30 16:42:45 2002 +0200 (2002-08-30)
changeset 13550 5a176b8dda84
parent 13549 f1522b892a4c
child 13570 0d6a0dce3ba3
permissions -rw-r--r--
removal of blast.overloaded
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in this Isabelle release
     6 ----------------------------
     7 
     8 *** General ***
     9 
    10 * Pure: locale specifications now produce predicate definitions
    11 according to the body of text (covering assumptions modulo local
    12 definitions); predicate "loc_axioms" covers newly introduced text,
    13 while "loc" is cumulative wrt. all included locale expressions; the
    14 latter view is presented only on export into the global theory
    15 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    16 on the old view without predicates;
    17 
    18 * Pure: predefined locales "var" and "struct" are useful for sharing
    19 parameters (as in CASL, for example); just specify something like
    20 ``var x + var y + struct M'' as import;
    21 
    22 * Pure: improved thms_containing: proper indexing of facts instead of
    23 raw theorems; check validity of results wrt. current name space;
    24 include local facts of proof configuration (also covers active
    25 locales), cover fixed variables in index; may use "_" in term
    26 specification; an optional limit for the number of printed facts may
    27 be given (the default is 40);
    28 
    29 * Pure: disallow duplicate fact bindings within new-style theory files
    30 (batch-mode only);
    31 
    32 * Provers: improved induct method: assumptions introduced by case
    33 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    34 the goal statement); "foo" still refers to all facts collectively;
    35 
    36 * Provers: the function blast.overloaded has been removed: all constants
    37 are regarded as potentially overloaded, which improves robustness in exchange
    38 for slight decrease in efficiency;
    39 
    40 * Isar: preview of problems to finish 'show' now produce an error
    41 rather than just a warning (in interactive mode);
    42 
    43 
    44 *** HOL ***
    45 
    46 * 'typedef' command has new option "open" to suppress the set
    47 definition;
    48 
    49 * functions Min and Max on finite sets have been introduced (theory
    50 Finite_Set);
    51 
    52 * attribute [symmetric] now works for relations as well; it turns
    53 (x,y) : R^-1 into (y,x) : R, and vice versa;
    54 
    55 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    56   In ProofGeneral the counter example appears in the trace buffer.
    57 
    58 * arith(_tac) does now know about div k and mod k where k is a numeral
    59 of type nat or int. It can solve simple goals like
    60 
    61   "0 < n ==> n div 2 < (n::nat)"
    62 
    63 but fails if divisibility plays a role like in
    64 
    65   "n div 2 + (n+1) div 2 = (n::nat)"
    66 
    67 * simp's arithmetic capabilities have been enhanced a bit: it now
    68 takes ~= in premises into account (by performing a case split);
    69 
    70 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
    71 are distributed over a sum of terms;
    72 
    73 * Real/HahnBanach: updated and adapted to locales;
    74 
    75 
    76 *** ZF ***
    77 
    78 * ZF/Constructible: consistency proof for AC (Gödel's constructible
    79 universe, etc.);
    80 
    81 * Main ZF: many theories converted to new-style format;
    82 
    83 
    84 *** ML ***
    85 
    86 * Pure: Tactic.prove provides sane interface for internal proofs;
    87 omits the infamous "standard" operation, so this is more appropriate
    88 than prove_goalw_cterm in many situations (e.g. in simprocs);
    89 
    90 * Pure: improved error reporting of simprocs;
    91 
    92 * Provers: Simplifier.simproc(_i) provides sane interface for setting
    93 up simprocs;
    94 
    95 
    96 
    97 New in Isabelle2002 (March 2002)
    98 --------------------------------
    99 
   100 *** Document preparation ***
   101 
   102 * greatly simplified document preparation setup, including more
   103 graceful interpretation of isatool usedir -i/-d/-D options, and more
   104 instructive isatool mkdir; users should basically be able to get
   105 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   106 users may run a separate document processing stage manually like this:
   107 "isatool usedir -D output HOL Test && isatool document Test/output";
   108 
   109 * theory dependency graph may now be incorporated into documents;
   110 isatool usedir -g true will produce session_graph.eps/.pdf for use
   111 with \includegraphics of LaTeX;
   112 
   113 * proper spacing of consecutive markup elements, especially text
   114 blocks after section headings;
   115 
   116 * support bold style (for single symbols only), input syntax is like
   117 this: "\<^bold>\<alpha>" or "\<^bold>A";
   118 
   119 * \<bullet> is now output as bold \cdot by default, which looks much
   120 better in printed text;
   121 
   122 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   123 note that these symbols are currently unavailable in Proof General /
   124 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   125 
   126 * isatool latex no longer depends on changed TEXINPUTS, instead
   127 isatool document copies the Isabelle style files to the target
   128 location;
   129 
   130 
   131 *** Isar ***
   132 
   133 * Pure/Provers: improved proof by cases and induction;
   134   - 'case' command admits impromptu naming of parameters (such as
   135     "case (Suc n)");
   136   - 'induct' method divinates rule instantiation from the inductive
   137     claim; no longer requires excessive ?P bindings for proper
   138     instantiation of cases;
   139   - 'induct' method properly enumerates all possibilities of set/type
   140     rules; as a consequence facts may be also passed through *type*
   141     rules without further ado;
   142   - 'induct' method now derives symbolic cases from the *rulified*
   143     rule (before it used to rulify cases stemming from the internal
   144     atomized version); this means that the context of a non-atomic
   145     statement becomes is included in the hypothesis, avoiding the
   146     slightly cumbersome show "PROP ?case" form;
   147   - 'induct' may now use elim-style induction rules without chaining
   148     facts, using ``missing'' premises from the goal state; this allows
   149     rules stemming from inductive sets to be applied in unstructured
   150     scripts, while still benefitting from proper handling of non-atomic
   151     statements; NB: major inductive premises need to be put first, all
   152     the rest of the goal is passed through the induction;
   153   - 'induct' proper support for mutual induction involving non-atomic
   154     rule statements (uses the new concept of simultaneous goals, see
   155     below);
   156   - append all possible rule selections, but only use the first
   157     success (no backtracking);
   158   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   159   - undeclared rule case names default to numbers 1, 2, 3, ...;
   160   - added 'print_induct_rules' (covered by help item in recent Proof
   161     General versions);
   162   - moved induct/cases attributes to Pure, methods to Provers;
   163   - generic method setup instantiated for FOL and HOL;
   164 
   165 * Pure: support multiple simultaneous goal statements, for example
   166 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   167 meta-level mechanism, this acts as if several individual goals had
   168 been stated separately; in particular common proof methods need to be
   169 repeated in order to cover all claims; note that a single elimination
   170 step is *not* sufficient to establish the two conjunctions, so this
   171 fails:
   172 
   173   assume "A & B" then have A and B ..   (*".." fails*)
   174 
   175 better use "obtain" in situations as above; alternative refer to
   176 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   177 
   178 * Pure: proper integration with ``locales''; unlike the original
   179 version by Florian Kammüller, Isar locales package high-level proof
   180 contexts rather than raw logical ones (e.g. we admit to include
   181 attributes everywhere); operations on locales include merge and
   182 rename; support for implicit arguments (``structures''); simultaneous
   183 type-inference over imports and text; see also HOL/ex/Locales.thy for
   184 some examples;
   185 
   186 * Pure: the following commands have been ``localized'', supporting a
   187 target locale specification "(in name)": 'lemma', 'theorem',
   188 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   189 stored both within the locale and at the theory level (exported and
   190 qualified by the locale name);
   191 
   192 * Pure: theory goals may now be specified in ``long'' form, with
   193 ad-hoc contexts consisting of arbitrary locale elements. for example
   194 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   195 definitions may be given, too); the result is a meta-level rule with
   196 the context elements being discharged in the obvious way;
   197 
   198 * Pure: new proof command 'using' allows to augment currently used
   199 facts after a goal statement ('using' is syntactically analogous to
   200 'apply', but acts on the goal's facts only); this allows chained facts
   201 to be separated into parts given before and after a claim, as in
   202 ``from a and b have C using d and e <proof>'';
   203 
   204 * Pure: renamed "antecedent" case to "rule_context";
   205 
   206 * Pure: new 'judgment' command records explicit information about the
   207 object-logic embedding (used by several tools internally); no longer
   208 use hard-wired "Trueprop";
   209 
   210 * Pure: added 'corollary' command;
   211 
   212 * Pure: fixed 'token_translation' command;
   213 
   214 * Pure: removed obsolete 'exported' attribute;
   215 
   216 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   217 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   218 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   219 
   220 * Pure: method 'atomize' presents local goal premises as object-level
   221 statements (atomic meta-level propositions); setup controlled via
   222 rewrite rules declarations of 'atomize' attribute; example
   223 application: 'induct' method with proper rule statements in improper
   224 proof *scripts*;
   225 
   226 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   227 now consider the syntactic context of assumptions, giving a better
   228 chance to get type-inference of the arguments right (this is
   229 especially important for locales);
   230 
   231 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   232 mode;
   233 
   234 * Pure/obtain: the formal conclusion "thesis", being marked as
   235 ``internal'', may no longer be reference directly in the text;
   236 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   237 situations;
   238 
   239 * Pure: generic 'sym' attribute which declares a rule both as pure
   240 'elim?' and for the 'symmetric' operation;
   241 
   242 * Pure: marginal comments ``--'' may now occur just anywhere in the
   243 text; the fixed correlation with particular command syntax has been
   244 discontinued;
   245 
   246 * Pure: new method 'rules' is particularly well-suited for proof
   247 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   248 but often produces more compact proof terms with less detours;
   249 
   250 * Pure/Provers/classical: simplified integration with pure rule
   251 attributes and methods; the classical "intro?/elim?/dest?"
   252 declarations coincide with the pure ones; the "rule" method no longer
   253 includes classically swapped intros; "intro" and "elim" methods no
   254 longer pick rules from the context; also got rid of ML declarations
   255 AddXIs/AddXEs/AddXDs; all of this has some potential for
   256 INCOMPATIBILITY;
   257 
   258 * Provers/classical: attribute 'swapped' produces classical inversions
   259 of introduction rules;
   260 
   261 * Provers/simplifier: 'simplified' attribute may refer to explicit
   262 rules instead of full simplifier context; 'iff' attribute handles
   263 conditional rules;
   264 
   265 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   266 
   267 * HOL: 'recdef' now fails on unfinished automated proofs, use
   268 "(permissive)" option to recover old behavior;
   269 
   270 * HOL: 'inductive' no longer features separate (collective) attributes
   271 for 'intros' (was found too confusing);
   272 
   273 * HOL: properly declared induction rules less_induct and
   274 wf_induct_rule;
   275 
   276 
   277 *** HOL ***
   278 
   279 * HOL: moved over to sane numeral syntax; the new policy is as
   280 follows:
   281 
   282   - 0 and 1 are polymorphic constants, which are defined on any
   283   numeric type (nat, int, real etc.);
   284 
   285   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   286   binary representation internally;
   287 
   288   - type nat has special constructor Suc, and generally prefers Suc 0
   289   over 1::nat and Suc (Suc 0) over 2::nat;
   290 
   291 This change may cause significant problems of INCOMPATIBILITY; here
   292 are some hints on converting existing sources:
   293 
   294   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   295   entities, so expressions involving "-" (unary or binary minus) need
   296   to be spaced properly;
   297 
   298   - existing occurrences of "1" may need to be constraint "1::nat" or
   299   even replaced by Suc 0; similar for old "2";
   300 
   301   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   302 
   303   - remove all special provisions on numerals in proofs;
   304 
   305 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   306 representation (depends on bin_arith_simps in the default context);
   307 
   308 * HOL: symbolic syntax for x^2 (numeral 2);
   309 
   310 * HOL: the class of all HOL types is now called "type" rather than
   311 "term"; INCOMPATIBILITY, need to adapt references to this type class
   312 in axclass/classes, instance/arities, and (usually rare) occurrences
   313 in typings (of consts etc.); internally the class is called
   314 "HOL.type", ML programs should refer to HOLogic.typeS;
   315 
   316 * HOL/record package improvements:
   317   - new derived operations "fields" to build a partial record section,
   318     "extend" to promote a fixed record to a record scheme, and
   319     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   320     declared as simp by default;
   321   - shared operations ("more", "fields", etc.) now need to be always
   322     qualified) --- potential INCOMPATIBILITY;
   323   - removed "make_scheme" operations (use "make" with "extend") --
   324     INCOMPATIBILITY;
   325   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   326   - provides cases/induct rules for use with corresponding Isar
   327     methods (for concrete records, record schemes, concrete more
   328     parts, and schematic more parts -- in that order);
   329   - internal definitions directly based on a light-weight abstract
   330     theory of product types over typedef rather than datatype;
   331 
   332 * HOL: generic code generator for generating executable ML code from
   333 specifications; specific support for HOL constructs such as inductive
   334 datatypes and sets, as well as recursive functions; can be invoked
   335 via 'generate_code' theory section;
   336 
   337 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   338 
   339 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   340 (beware of argument permutation!);
   341 
   342 * HOL: linorder_less_split superseded by linorder_cases;
   343 
   344 * HOL/List: "nodups" renamed to "distinct";
   345 
   346 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   347 to peripheral theory "Hilbert_Choice";
   348 
   349 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   350 in this (rare) case use:
   351 
   352   delSWrapper "split_all_tac"
   353   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   354 
   355 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   356 MAY FAIL;
   357 
   358 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   359 Isabelle's type classes, ^ on functions and relations has too general
   360 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   361 necessary to attach explicit type constraints;
   362 
   363 * HOL/Relation: the prefix name of the infix "O" has been changed from
   364 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   365 renamed accordingly (eg "compI" -> "rel_compI").
   366 
   367 * HOL: syntax translations now work properly with numerals and records
   368 expressions;
   369 
   370 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   371 of "lam" -- INCOMPATIBILITY;
   372 
   373 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   374 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   375 renamed "Product_Type.unit";
   376 
   377 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   378 
   379 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   380 the "cases" method);
   381 
   382 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   383 Florian Kammüller);
   384 
   385 * HOL/IMP: updated and converted to new-style theory format; several
   386 parts turned into readable document, with proper Isar proof texts and
   387 some explanations (by Gerwin Klein);
   388 
   389 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   390 
   391 * HOL-Hyperreal is now a logic image;
   392 
   393 
   394 *** HOLCF ***
   395 
   396 * Isar: consts/constdefs supports mixfix syntax for continuous
   397 operations;
   398 
   399 * Isar: domain package adapted to new-style theory format, e.g. see
   400 HOLCF/ex/Dnat.thy;
   401 
   402 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   403 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   404 lift.induct_tac, always use UU instead of Undef;
   405 
   406 * HOLCF/IMP: updated and converted to new-style theory;
   407 
   408 
   409 *** ZF ***
   410 
   411 * Isar: proper integration of logic-specific tools and packages,
   412 including theory commands '(co)inductive', '(co)datatype',
   413 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   414 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   415 
   416 * theory Main no longer includes AC; for the Axiom of Choice, base
   417 your theory on Main_ZFC;
   418 
   419 * the integer library now covers quotients and remainders, with many
   420 laws relating division to addition, multiplication, etc.;
   421 
   422 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   423 typeless version of the formalism;
   424 
   425 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   426 format;
   427 
   428 * ZF/Induct: new directory for examples of inductive definitions,
   429 including theory Multiset for multiset orderings; converted to
   430 new-style theory format;
   431 
   432 * ZF: many new theorems about lists, ordinals, etc.;
   433 
   434 
   435 *** General ***
   436 
   437 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   438 variable proof controls level of detail: 0 = no proofs (only oracle
   439 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   440 also ref manual for further ML interfaces;
   441 
   442 * Pure/axclass: removed obsolete ML interface
   443 goal_subclass/goal_arity;
   444 
   445 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   446 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   447 separate tokens, so expressions involving minus need to be spaced
   448 properly;
   449 
   450 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   451 rather than "infixl" or "infixr";
   452 
   453 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   454 sort constraint specifications in type inference; e.g. "x::_::foo"
   455 ensures that the type of "x" is of sort "foo" (but not necessarily a
   456 type variable);
   457 
   458 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   459 control output of nested => (types); the default behavior is
   460 "type_brackets";
   461 
   462 * Pure/syntax: builtin parse translation for "_constify" turns valued
   463 tokens into AST constants;
   464 
   465 * Pure/syntax: prefer later declarations of translations and print
   466 translation functions; potential INCOMPATIBILITY: need to reverse
   467 multiple declarations for same syntax element constant;
   468 
   469 * Pure/show_hyps reset by default (in accordance to existing Isar
   470 practice);
   471 
   472 * Provers/classical: renamed addaltern to addafter, addSaltern to
   473 addSafter;
   474 
   475 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   476 as well;
   477 
   478 * system: tested support for MacOS X; should be able to get Isabelle +
   479 Proof General to work in a plain Terminal after installing Poly/ML
   480 (e.g. from the Isabelle distribution area) and GNU bash alone
   481 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   482 support requires further installations, e.g. from
   483 http://fink.sourceforge.net/);
   484 
   485 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   486 
   487 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   488 of 40 MB), cf. ML_OPTIONS;
   489 
   490 * system: Proof General keywords specification is now part of the
   491 Isabelle distribution (see etc/isar-keywords.el);
   492 
   493 * system: support for persistent Proof General sessions (refrain from
   494 outdating all loaded theories on startup); user may create writable
   495 logic images like this: ``isabelle -q HOL Test'';
   496 
   497 * system: smart selection of Isabelle process versus Isabelle
   498 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   499 run both "isabelle" and "Isabelle" even if file names are badly
   500 damaged (executable inspects the case of the first letter of its own
   501 name); added separate "isabelle-process" and "isabelle-interface";
   502 
   503 * system: refrain from any attempt at filtering input streams; no
   504 longer support ``8bit'' encoding of old isabelle font, instead proper
   505 iso-latin characters may now be used; the related isatools
   506 "symbolinput" and "nonascii" have disappeared as well;
   507 
   508 * system: removed old "xterm" interface (the print modes "xterm" and
   509 "xterm_color" are still available for direct use in a suitable
   510 terminal);
   511 
   512 
   513 
   514 New in Isabelle99-2 (February 2001)
   515 -----------------------------------
   516 
   517 *** Overview of INCOMPATIBILITIES ***
   518 
   519 * HOL: please note that theories in the Library and elsewhere often use the
   520 new-style (Isar) format; to refer to their theorems in an ML script you must
   521 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   522 
   523 * HOL: inductive package no longer splits induction rule aggressively,
   524 but only as far as specified by the introductions given; the old
   525 format may be recovered via ML function complete_split_rule or attribute
   526 'split_rule (complete)';
   527 
   528 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   529 gfp_Tarski to gfp_unfold;
   530 
   531 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   532 
   533 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   534 relation); infix "^^" has been renamed "``"; infix "``" has been
   535 renamed "`"; "univalent" has been renamed "single_valued";
   536 
   537 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   538 operation;
   539 
   540 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   541 
   542 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   543 
   544 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   545 consequence, it is no longer monotonic wrt. the local goal context
   546 (which is now passed through the inductive cases);
   547 
   548 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   549 \<gg> to \<ggreater>;
   550 
   551 
   552 *** Document preparation ***
   553 
   554 * \isabellestyle{NAME} selects version of Isabelle output (currently
   555 available: are "it" for near math-mode best-style output, "sl" for
   556 slanted text style, and "tt" for plain type-writer; if no
   557 \isabellestyle command is given, output is according to slanted
   558 type-writer);
   559 
   560 * support sub/super scripts (for single symbols only), input syntax is
   561 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   562 
   563 * some more standard symbols; see Appendix A of the system manual for
   564 the complete list of symbols defined in isabellesym.sty;
   565 
   566 * improved isabelle style files; more abstract symbol implementation
   567 (should now use \isamath{...} and \isatext{...} in custom symbol
   568 definitions);
   569 
   570 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   571 state; Note that presentation of goal states does not conform to
   572 actual human-readable proof documents.  Please do not include goal
   573 states into document output unless you really know what you are doing!
   574 
   575 * proper indentation of antiquoted output with proportional LaTeX
   576 fonts;
   577 
   578 * no_document ML operator temporarily disables LaTeX document
   579 generation;
   580 
   581 * isatool unsymbolize tunes sources for plain ASCII communication;
   582 
   583 
   584 *** Isar ***
   585 
   586 * Pure: Isar now suffers initial goal statements to contain unbound
   587 schematic variables (this does not conform to actual readable proof
   588 documents, due to unpredictable outcome and non-compositional proof
   589 checking); users who know what they are doing may use schematic goals
   590 for Prolog-style synthesis of proven results;
   591 
   592 * Pure: assumption method (an implicit finishing) now handles actual
   593 rules as well;
   594 
   595 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   596 initial goal, declare "that" only as Pure intro (only for single
   597 steps); the "that" rule assumption may now be involved in implicit
   598 finishing, thus ".." becomes a feasible for trivial obtains;
   599 
   600 * Pure: default proof step now includes 'intro_classes'; thus trivial
   601 instance proofs may be performed by "..";
   602 
   603 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   604 statements as well;
   605 
   606 * Pure: more robust selection of calculational rules;
   607 
   608 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   609 rule (as well as the assumption rule);
   610 
   611 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   612 lemmas, using the graph browser tool;
   613 
   614 * Pure: predict failure of "show" in interactive mode;
   615 
   616 * Pure: 'thms_containing' now takes actual terms as arguments;
   617 
   618 * HOL: improved method 'induct' --- now handles non-atomic goals
   619 (potential INCOMPATIBILITY); tuned error handling;
   620 
   621 * HOL: cases and induct rules now provide explicit hints about the
   622 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   623 any remaining facts are inserted into the goal verbatim;
   624 
   625 * HOL: local contexts (aka cases) may now contain term bindings as
   626 well; the 'cases' and 'induct' methods new provide a ?case binding for
   627 the result to be shown in each case;
   628 
   629 * HOL: added 'recdef_tc' command;
   630 
   631 * isatool convert assists in eliminating legacy ML scripts;
   632 
   633 
   634 *** HOL ***
   635 
   636 * HOL/Library: a collection of generic theories to be used together
   637 with main HOL; the theory loader path already includes this directory
   638 by default; the following existing theories have been moved here:
   639 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   640 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   641 
   642 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   643 modelling and verification task performed in Isabelle/HOL +
   644 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   645 
   646 * HOL/Algebra: special summation operator SUM no longer exists, it has
   647 been replaced by setsum; infix 'assoc' now has priority 50 (like
   648 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   649 'domain', this makes the theory consistent with mathematical
   650 literature;
   651 
   652 * HOL basics: added overloaded operations "inverse" and "divide"
   653 (infix "/"), syntax for generic "abs" operation, generic summation
   654 operator \<Sum>;
   655 
   656 * HOL/typedef: simplified package, provide more useful rules (see also
   657 HOL/subset.thy);
   658 
   659 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   660 now expressed as a proper nested rule (old-style tactic scripts may
   661 require atomize_strip_tac to cope with non-atomic premises);
   662 
   663 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   664 to "split_conv" (old name still available for compatibility);
   665 
   666 * HOL: improved concrete syntax for strings (e.g. allows translation
   667 rules with string literals);
   668 
   669 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   670  and Fleuriot's mechanization of analysis, including the transcendental
   671  functions for the reals;
   672 
   673 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   674 
   675 
   676 *** CTT ***
   677 
   678 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   679 "lam" is displayed as TWO lambda-symbols
   680 
   681 * CTT: theory Main now available, containing everything (that is, Bool
   682 and Arith);
   683 
   684 
   685 *** General ***
   686 
   687 * Pure: the Simplifier has been implemented properly as a derived rule
   688 outside of the actual kernel (at last!); the overall performance
   689 penalty in practical applications is about 50%, while reliability of
   690 the Isabelle inference kernel has been greatly improved;
   691 
   692 * print modes "brackets" and "no_brackets" control output of nested =>
   693 (types) and ==> (props); the default behaviour is "brackets";
   694 
   695 * Provers: fast_tac (and friends) now handle actual object-logic rules
   696 as assumptions as well;
   697 
   698 * system: support Poly/ML 4.0;
   699 
   700 * system: isatool install handles KDE version 1 or 2;
   701 
   702 
   703 
   704 New in Isabelle99-1 (October 2000)
   705 ----------------------------------
   706 
   707 *** Overview of INCOMPATIBILITIES ***
   708 
   709 * HOL: simplification of natural numbers is much changed; to partly
   710 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   711 issue the following ML commands:
   712 
   713   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   714   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   715 
   716 * HOL: simplification no longer dives into case-expressions; this is
   717 controlled by "t.weak_case_cong" for each datatype t;
   718 
   719 * HOL: nat_less_induct renamed to less_induct;
   720 
   721 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   722 fixsome to patch .thy and .ML sources automatically;
   723 
   724   select_equality  -> some_equality
   725   select_eq_Ex     -> some_eq_ex
   726   selectI2EX       -> someI2_ex
   727   selectI2         -> someI2
   728   selectI          -> someI
   729   select1_equality -> some1_equality
   730   Eps_sym_eq       -> some_sym_eq_trivial
   731   Eps_eq           -> some_eq_trivial
   732 
   733 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   734 
   735 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   736 instead);
   737 
   738 * HOL: the recursion equations generated by 'recdef' are now called
   739 f.simps instead of f.rules;
   740 
   741 * HOL: qed_spec_mp now also handles bounded ALL as well;
   742 
   743 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   744 sometimes be needed;
   745 
   746 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   747 
   748 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   749 
   750 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   751 product is now "<*>" instead of "Times"; the lexicographic product is
   752 now "<*lex*>" instead of "**";
   753 
   754 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   755 of main HOL, but was unused); better use HOL's datatype package;
   756 
   757 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   758 the old syntax may be recovered as follows:
   759 
   760   syntax (symbols)
   761     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   762       (infixl "\\<oplus>" 100)
   763 
   764 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   765 
   766 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   767 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   768 internally;
   769 
   770 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   771 changed from A/r to A//r;
   772 
   773 * ZF: new treatment of arithmetic (nat & int) may break some old
   774 proofs;
   775 
   776 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   777 rulify -> rule_format, elimify -> elim_format, ...);
   778 
   779 * Isar/Provers: intro/elim/dest attributes changed; renamed
   780 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   781 should have to change intro!! to intro? only); replaced "delrule" by
   782 "rule del";
   783 
   784 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   785 
   786 * Provers: strengthened force_tac by using new first_best_tac;
   787 
   788 * LaTeX document preparation: several changes of isabelle.sty (see
   789 lib/texinputs);
   790 
   791 
   792 *** Document preparation ***
   793 
   794 * formal comments (text blocks etc.) in new-style theories may now
   795 contain antiquotations of thm/prop/term/typ/text to be presented
   796 according to latex print mode; concrete syntax is like this:
   797 @{term[show_types] "f(x) = a + x"};
   798 
   799 * isatool mkdir provides easy setup of Isabelle session directories,
   800 including proper document sources;
   801 
   802 * generated LaTeX sources are now deleted after successful run
   803 (isatool document -c); may retain a copy somewhere else via -D option
   804 of isatool usedir;
   805 
   806 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   807 style files, achieving self-contained LaTeX sources and simplifying
   808 LaTeX debugging;
   809 
   810 * old-style theories now produce (crude) LaTeX output as well;
   811 
   812 * browser info session directories are now self-contained (may be put
   813 on WWW server seperately); improved graphs of nested sessions; removed
   814 graph for 'all sessions';
   815 
   816 * several improvements in isabelle style files; \isabellestyle{it}
   817 produces fake math mode output; \isamarkupheader is now \section by
   818 default; see lib/texinputs/isabelle.sty etc.;
   819 
   820 
   821 *** Isar ***
   822 
   823 * Isar/Pure: local results and corresponding term bindings are now
   824 subject to Hindley-Milner polymorphism (similar to ML); this
   825 accommodates incremental type-inference very nicely;
   826 
   827 * Isar/Pure: new derived language element 'obtain' supports
   828 generalized existence reasoning;
   829 
   830 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   831 support accumulation of results, without applying any rules yet;
   832 useful to collect intermediate results without explicit name
   833 references, and for use with transitivity rules with more than 2
   834 premises;
   835 
   836 * Isar/Pure: scalable support for case-analysis type proofs: new
   837 'case' language element refers to local contexts symbolically, as
   838 produced by certain proof methods; internally, case names are attached
   839 to theorems as "tags";
   840 
   841 * Isar/Pure: theory command 'hide' removes declarations from
   842 class/type/const name spaces;
   843 
   844 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   845 indicate potential overloading;
   846 
   847 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   848 
   849 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   850 "{a,b,c}" instead of {a,b,c};
   851 
   852 * Isar/Pure now provides its own version of intro/elim/dest
   853 attributes; useful for building new logics, but beware of confusion
   854 with the version in Provers/classical;
   855 
   856 * Isar/Pure: the local context of (non-atomic) goals is provided via
   857 case name 'antecedent';
   858 
   859 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   860 to the current context is now done automatically);
   861 
   862 * Isar/Pure: theory command 'method_setup' provides a simple interface
   863 for definining proof methods in ML;
   864 
   865 * Isar/Provers: intro/elim/dest attributes changed; renamed
   866 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   867 most cases, one should have to change intro!! to intro? only);
   868 replaced "delrule" by "rule del";
   869 
   870 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   871 'symmetric' attribute (the latter supercedes [RS sym]);
   872 
   873 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   874 method modifier); 'simp' method: 'only:' modifier removes loopers as
   875 well (including splits);
   876 
   877 * Isar/Provers: Simplifier and Classical methods now support all kind
   878 of modifiers used in the past, including 'cong', 'iff', etc.
   879 
   880 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   881 of Simplifier and Classical reasoner);
   882 
   883 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   884 now support named cases; major packages (inductive, datatype, primrec,
   885 recdef) support case names and properly name parameters;
   886 
   887 * Isar/HOL: new transitivity rules for substitution in inequalities --
   888 monotonicity conditions are extracted to be proven at end of
   889 calculations;
   890 
   891 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   892 method anyway;
   893 
   894 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   895 split_if split_if_asm; datatype package provides theorems foo.splits =
   896 foo.split foo.split_asm for each datatype;
   897 
   898 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   899 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   900 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   901 use "(cases (simplified))" method in proper proof texts);
   902 
   903 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   904 
   905 * Isar: names of theorems etc. may be natural numbers as well;
   906 
   907 * Isar: 'pr' command: optional arguments for goals_limit and
   908 ProofContext.prems_limit; no longer prints theory contexts, but only
   909 proof states;
   910 
   911 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   912 additional print modes to be specified; e.g. "pr(latex)" will print
   913 proof state according to the Isabelle LaTeX style;
   914 
   915 * Isar: improved support for emulating tactic scripts, including proof
   916 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   917 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   918 (for HOL datatypes);
   919 
   920 * Isar: simplified (more robust) goal selection of proof methods: 1st
   921 goal, all goals, or explicit goal specifier (tactic emulation); thus
   922 'proof method scripts' have to be in depth-first order;
   923 
   924 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   925 
   926 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   927 should instead use individual commands for printing items
   928 (print_commands, print_methods etc.);
   929 
   930 * Isar: added 'nothing' --- the empty list of theorems;
   931 
   932 
   933 *** HOL ***
   934 
   935 * HOL/MicroJava: formalization of a fragment of Java, together with a
   936 corresponding virtual machine and a specification of its bytecode
   937 verifier and a lightweight bytecode verifier, including proofs of
   938 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   939 Cornelia Pusch (see also the homepage of project Bali at
   940 http://isabelle.in.tum.de/Bali/);
   941 
   942 * HOL/Algebra: new theory of rings and univariate polynomials, by
   943 Clemens Ballarin;
   944 
   945 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   946 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   947 Rasmussen;
   948 
   949 * HOL/Lattice: fundamental concepts of lattice theory and order
   950 structures, including duals, properties of bounds versus algebraic
   951 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   952 Theorem for complete lattices etc.; may also serve as a demonstration
   953 for abstract algebraic reasoning using axiomatic type classes, and
   954 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   955 
   956 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   957 von Oheimb;
   958 
   959 * HOL/IMPP: extension of IMP with local variables and mutually
   960 recursive procedures, by David von Oheimb;
   961 
   962 * HOL/Lambda: converted into new-style theory and document;
   963 
   964 * HOL/ex/Multiquote: example of multiple nested quotations and
   965 anti-quotations -- basically a generalized version of de-Bruijn
   966 representation; very useful in avoiding lifting of operations;
   967 
   968 * HOL/record: added general record equality rule to simpset; fixed
   969 select-update simplification procedure to handle extended records as
   970 well; admit "r" as field name;
   971 
   972 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   973 other numeric types and also as the identity of groups, rings, etc.;
   974 
   975 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   976 Types nat and int belong to this axclass;
   977 
   978 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   979    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   980    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   981   two terms #m*u and #n*u are replaced by #(m+n)*u
   982     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   983   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   984     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   985 
   986 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   987 powerful prover for predicate logic but knows nothing of clasets; see
   988 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   989 
   990 * HOL: new version of "case_tac" subsumes both boolean case split and
   991 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   992 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   993 
   994 * HOL: simplification no longer dives into case-expressions: only the
   995 selector expression is simplified, but not the remaining arms; to
   996 enable full simplification of case-expressions for datatype t, you may
   997 remove t.weak_case_cong from the simpset, either globally (Delcongs
   998 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   999 
  1000 * HOL/recdef: the recursion equations generated by 'recdef' for
  1001 function 'f' are now called f.simps instead of f.rules; if all
  1002 termination conditions are proved automatically, these simplification
  1003 rules are added to the simpset, as in primrec; rules may be named
  1004 individually as well, resulting in a separate list of theorems for
  1005 each equation;
  1006 
  1007 * HOL/While is a new theory that provides a while-combinator. It
  1008 permits the definition of tail-recursive functions without the
  1009 provision of a termination measure. The latter is necessary once the
  1010 invariant proof rule for while is applied.
  1011 
  1012 * HOL: new (overloaded) notation for the set of elements below/above
  1013 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1014 
  1015 * HOL: theorems impI, allI, ballI bound as "strip";
  1016 
  1017 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1018 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1019 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1020 
  1021 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1022 
  1023 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1024 main HOL, but was unused);
  1025 
  1026 * HOL: fewer consts declared as global (e.g. have to refer to
  1027 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1028 
  1029 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1030 in case of overlap with user translations (e.g. judgements over
  1031 tuples); (note that the underlying logical represenation is still
  1032 bogus);
  1033 
  1034 
  1035 *** ZF ***
  1036 
  1037 * ZF: simplification automatically cancels common terms in arithmetic
  1038 expressions over nat and int;
  1039 
  1040 * ZF: new treatment of nat to minimize type-checking: all operators
  1041 coerce their operands to a natural number using the function natify,
  1042 making the algebraic laws unconditional;
  1043 
  1044 * ZF: as above, for int: operators coerce their operands to an integer
  1045 using the function intify;
  1046 
  1047 * ZF: the integer library now contains many of the usual laws for the
  1048 orderings, including $<=, and monotonicity laws for $+ and $*;
  1049 
  1050 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1051 simplification;
  1052 
  1053 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1054 to the simplifier and classical reasoner simultaneously;
  1055 
  1056 
  1057 *** General ***
  1058 
  1059 * Provers: blast_tac now handles actual object-logic rules as
  1060 assumptions; note that auto_tac uses blast_tac internally as well;
  1061 
  1062 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1063 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1064 
  1065 * Provers: delrules now handles destruct rules as well (no longer need
  1066 explicit make_elim);
  1067 
  1068 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1069   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1070 use instead the strong form,
  1071   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1072 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1073 from destruct-rules;
  1074 
  1075 * Provers: Simplifier.easy_setup provides a fast path to basic
  1076 Simplifier setup for new object-logics;
  1077 
  1078 * Pure: AST translation rules no longer require constant head on LHS;
  1079 
  1080 * Pure: improved name spaces: ambiguous output is qualified; support
  1081 for hiding of names;
  1082 
  1083 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1084 XSYMBOL_HOME; no longer need to do manual configuration in most
  1085 situations;
  1086 
  1087 * system: compression of ML heaps images may now be controlled via -c
  1088 option of isabelle and isatool usedir (currently only observed by
  1089 Poly/ML);
  1090 
  1091 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1092 useful for remote X11);
  1093 
  1094 * system: provide TAGS file for Isabelle sources;
  1095 
  1096 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1097 order;
  1098 
  1099 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1100 timing flag supersedes proof_timing and Toplevel.trace;
  1101 
  1102 * ML: new combinators |>> and |>>> for incremental transformations
  1103 with secondary results (e.g. certain theory extensions):
  1104 
  1105 * ML: PureThy.add_defs gets additional argument to indicate potential
  1106 overloading (usually false);
  1107 
  1108 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1109 results;
  1110 
  1111 
  1112 
  1113 New in Isabelle99 (October 1999)
  1114 --------------------------------
  1115 
  1116 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1117 
  1118 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1119 are no longer simplified.  (This allows the simplifier to unfold recursive
  1120 functional programs.)  To restore the old behaviour, declare
  1121 
  1122     Delcongs [if_weak_cong];
  1123 
  1124 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1125 complement;
  1126 
  1127 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1128 
  1129 * HOL/datatype: mutual_induct_tac no longer exists --
  1130   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1131 
  1132 * HOL/typedef: fixed type inference for representing set; type
  1133 arguments now have to occur explicitly on the rhs as type constraints;
  1134 
  1135 * ZF: The con_defs part of an inductive definition may no longer refer
  1136 to constants declared in the same theory;
  1137 
  1138 * HOL, ZF: the function mk_cases, generated by the inductive
  1139 definition package, has lost an argument.  To simplify its result, it
  1140 uses the default simpset instead of a supplied list of theorems.
  1141 
  1142 * HOL/List: the constructors of type list are now Nil and Cons;
  1143 
  1144 * Simplifier: the type of the infix ML functions
  1145         setSSolver addSSolver setSolver addSolver
  1146 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1147 for packaging solvers. A solver is created via
  1148         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1149 where the string argument is only a comment.
  1150 
  1151 
  1152 *** Proof tools ***
  1153 
  1154 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1155 decision procedure for linear arithmetic. Currently it is used for
  1156 types `nat', `int', and `real' in HOL (see below); it can, should and
  1157 will be instantiated for other types and logics as well.
  1158 
  1159 * The simplifier now accepts rewrite rules with flexible heads, eg
  1160      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1161   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1162   matching.
  1163 
  1164 
  1165 *** General ***
  1166 
  1167 * New Isabelle/Isar subsystem provides an alternative to traditional
  1168 tactical theorem proving; together with the ProofGeneral/isar user
  1169 interface it offers an interactive environment for developing human
  1170 readable proof documents (Isar == Intelligible semi-automated
  1171 reasoning); for further information see isatool doc isar-ref,
  1172 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1173 
  1174 * improved and simplified presentation of theories: better HTML markup
  1175 (including colors), graph views in several sizes; isatool usedir now
  1176 provides a proper interface for user theories (via -P option); actual
  1177 document preparation based on (PDF)LaTeX is available as well (for
  1178 new-style theories only); see isatool doc system for more information;
  1179 
  1180 * native support for Proof General, both for classic Isabelle and
  1181 Isabelle/Isar;
  1182 
  1183 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1184 using the graph browser tool;
  1185 
  1186 * Isabelle manuals now also available as PDF;
  1187 
  1188 * theory loader rewritten from scratch (may not be fully
  1189 bug-compatible); old loadpath variable has been replaced by show_path,
  1190 add_path, del_path, reset_path functions; new operations such as
  1191 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1192 isatool doc ref);
  1193 
  1194 * improved isatool install: option -k creates KDE application icon,
  1195 option -p DIR installs standalone binaries;
  1196 
  1197 * added ML_PLATFORM setting (useful for cross-platform installations);
  1198 more robust handling of platform specific ML images for SML/NJ;
  1199 
  1200 * the settings environment is now statically scoped, i.e. it is never
  1201 created again in sub-processes invoked from isabelle, isatool, or
  1202 Isabelle;
  1203 
  1204 * path element specification '~~' refers to '$ISABELLE_HOME';
  1205 
  1206 * in locales, the "assumes" and "defines" parts may be omitted if
  1207 empty;
  1208 
  1209 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1210 long arrows);
  1211 
  1212 * new print_mode "HTML";
  1213 
  1214 * new flag show_tags controls display of tags of theorems (which are
  1215 basically just comments that may be attached by some tools);
  1216 
  1217 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1218 mode and goal output format:
  1219 
  1220 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1221 244c244
  1222 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1223 ---
  1224 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1225 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1226 181c181
  1227 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1228 ---
  1229 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1230 
  1231 * function bind_thms stores lists of theorems (cf. bind_thm);
  1232 
  1233 * new shorthand tactics ftac, eatac, datac, fatac;
  1234 
  1235 * qed (and friends) now accept "" as result name; in that case the
  1236 theorem is not stored, but proper checks and presentation of the
  1237 result still apply;
  1238 
  1239 * theorem database now also indexes constants "Trueprop", "all",
  1240 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1241 
  1242 
  1243 *** HOL ***
  1244 
  1245 ** HOL arithmetic **
  1246 
  1247 * There are now decision procedures for linear arithmetic over nat and
  1248 int:
  1249 
  1250 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1251 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1252 are treated as atomic; subformulae not involving type `nat' or `int'
  1253 are ignored; quantified subformulae are ignored unless they are
  1254 positive universal or negative existential. The tactic has to be
  1255 invoked by hand and can be a little bit slow. In particular, the
  1256 running time is exponential in the number of occurrences of `min' and
  1257 `max', and `-' on `nat'.
  1258 
  1259 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1260 (negated) (in)equalities among the premises and the conclusion into
  1261 account (i.e. no compound formulae) and does not know about `min' and
  1262 `max', and `-' on `nat'. It is fast and is used automatically by the
  1263 simplifier.
  1264 
  1265 NB: At the moment, these decision procedures do not cope with mixed
  1266 nat/int formulae where the two parts interact, such as `m < n ==>
  1267 int(m) < int(n)'.
  1268 
  1269 * HOL/Numeral provides a generic theory of numerals (encoded
  1270 efficiently as bit strings); setup for types nat/int/real is in place;
  1271 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1272 int, existing theories and proof scripts may require a few additional
  1273 type constraints;
  1274 
  1275 * integer division and remainder can now be performed on constant
  1276 arguments;
  1277 
  1278 * many properties of integer multiplication, division and remainder
  1279 are now available;
  1280 
  1281 * An interface to the Stanford Validity Checker (SVC) is available through the
  1282 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1283 are proved automatically.  SVC must be installed separately, and its results
  1284 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1285 invocation of the underlying oracle).  For SVC see
  1286   http://verify.stanford.edu/SVC
  1287 
  1288 * IsaMakefile: the HOL-Real target now builds an actual image;
  1289 
  1290 
  1291 ** HOL misc **
  1292 
  1293 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1294 (in Isabelle/Isar) -- by Gertrud Bauer;
  1295 
  1296 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1297 analysis for assembly languages with subtypes;
  1298 
  1299 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1300 -- avoids syntactic ambiguities and treats state, transition, and
  1301 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1302 changed syntax and (many) tactics;
  1303 
  1304 * HOL/inductive: Now also handles more general introduction rules such
  1305   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1306   theorems are now maintained within the theory (maintained via the
  1307   "mono" attribute);
  1308 
  1309 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1310   (using function types) such as
  1311 
  1312   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1313 
  1314 * HOL/record: record_simproc (part of the default simpset) takes care
  1315 of selectors applied to updated records; record_split_tac is no longer
  1316 part of the default claset; update_defs may now be removed from the
  1317 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1318 
  1319   claset_ref () := claset() addSWrapper record_split_wrapper;
  1320   Delsimprocs [record_simproc]
  1321 
  1322 * HOL/typedef: fixed type inference for representing set; type
  1323 arguments now have to occur explicitly on the rhs as type constraints;
  1324 
  1325 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1326 names rather than an ML expression;
  1327 
  1328 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1329 supplied later.  Program schemes can be defined, such as
  1330     "While B C s = (if B s then While B C (C s) else s)"
  1331 where the well-founded relation can be chosen after B and C have been given.
  1332 
  1333 * HOL/List: the constructors of type list are now Nil and Cons;
  1334 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1335 course, ML tools referring to List.list.op # etc. have to be adapted;
  1336 
  1337 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1338 disabled by default; run isabelle with option -m HOL to get back to
  1339 the original Gordon/HOL-style output;
  1340 
  1341 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1342 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1343 
  1344 * HOL basic syntax simplified (more orthogonal): all variants of
  1345 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1346 Eps operator is provided as well: "SOME x. P[x]";
  1347 
  1348 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1349 
  1350 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1351 thus available for user theories;
  1352 
  1353 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1354 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1355 time;
  1356 
  1357 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1358 several times and then mp;
  1359 
  1360 
  1361 *** LK ***
  1362 
  1363 * the notation <<...>> is now available as a notation for sequences of
  1364 formulas;
  1365 
  1366 * the simplifier is now installed
  1367 
  1368 * the axiom system has been generalized (thanks to Soren Heilmann)
  1369 
  1370 * the classical reasoner now has a default rule database
  1371 
  1372 
  1373 *** ZF ***
  1374 
  1375 * new primrec section allows primitive recursive functions to be given
  1376 directly (as in HOL) over datatypes and the natural numbers;
  1377 
  1378 * new tactics induct_tac and exhaust_tac for induction (or case
  1379 analysis) over datatypes and the natural numbers;
  1380 
  1381 * the datatype declaration of type T now defines the recursor T_rec;
  1382 
  1383 * simplification automatically does freeness reasoning for datatype
  1384 constructors;
  1385 
  1386 * automatic type-inference, with AddTCs command to insert new
  1387 type-checking rules;
  1388 
  1389 * datatype introduction rules are now added as Safe Introduction rules
  1390 to the claset;
  1391 
  1392 * the syntax "if P then x else y" is now available in addition to
  1393 if(P,x,y);
  1394 
  1395 
  1396 *** Internal programming interfaces ***
  1397 
  1398 * tuned simplifier trace output; new flag debug_simp;
  1399 
  1400 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1401 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1402 
  1403 * AxClass.axclass_tac lost the theory argument;
  1404 
  1405 * tuned current_goals_markers semantics: begin / end goal avoids
  1406 printing empty lines;
  1407 
  1408 * removed prs and prs_fn hook, which was broken because it did not
  1409 include \n in its semantics, forcing writeln to add one
  1410 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1411 string -> unit if you really want to output text without newline;
  1412 
  1413 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1414 plain output, interface builders may have to enable 'isabelle_font'
  1415 mode to get Isabelle font glyphs as before;
  1416 
  1417 * refined token_translation interface; INCOMPATIBILITY: output length
  1418 now of type real instead of int;
  1419 
  1420 * theory loader actions may be traced via new ThyInfo.add_hook
  1421 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1422 your own database of information attached to *whole* theories -- as
  1423 opposed to intra-theory data slots offered via TheoryDataFun;
  1424 
  1425 * proper handling of dangling sort hypotheses (at last!);
  1426 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1427 extra sort hypotheses that can be witnessed from the type signature;
  1428 the force_strip_shyps flag is gone, any remaining shyps are simply
  1429 left in the theorem (with a warning issued by strip_shyps_warning);
  1430 
  1431 
  1432 
  1433 New in Isabelle98-1 (October 1998)
  1434 ----------------------------------
  1435 
  1436 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1437 
  1438 * several changes of automated proof tools;
  1439 
  1440 * HOL: major changes to the inductive and datatype packages, including
  1441 some minor incompatibilities of theory syntax;
  1442 
  1443 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1444 called `inj_on';
  1445 
  1446 * HOL: removed duplicate thms in Arith:
  1447   less_imp_add_less  should be replaced by  trans_less_add1
  1448   le_imp_add_le      should be replaced by  trans_le_add1
  1449 
  1450 * HOL: unary minus is now overloaded (new type constraints may be
  1451 required);
  1452 
  1453 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1454 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1455 now taken as an integer constant.
  1456 
  1457 * Pure: ML function 'theory_of' renamed to 'theory';
  1458 
  1459 
  1460 *** Proof tools ***
  1461 
  1462 * Simplifier:
  1463   1. Asm_full_simp_tac is now more aggressive.
  1464      1. It will sometimes reorient premises if that increases their power to
  1465         simplify.
  1466      2. It does no longer proceed strictly from left to right but may also
  1467         rotate premises to achieve further simplification.
  1468      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1469      old Asm_full_simp_tac in that it does not rotate premises.
  1470   2. The simplifier now knows a little bit about nat-arithmetic.
  1471 
  1472 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1473 allows for selected deletion of wrappers, by introduction of names for
  1474 wrapper functionals.  This implies that addbefore, addSbefore,
  1475 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1476 and that adding two tactics with the same name overwrites the first
  1477 one (emitting a warning).
  1478   type wrapper = (int -> tactic) -> (int -> tactic)
  1479   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1480   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1481   delWrapper, delSWrapper: claset *  string            -> claset
  1482   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1483 
  1484 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1485 semantics; addbefore now affects only the unsafe part of step_tac
  1486 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1487 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1488 by Force_tac;
  1489 
  1490 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1491 compWrapper; added safe wrapper (and access functions for it);
  1492 
  1493 * HOL/split_all_tac is now much faster and fails if there is nothing
  1494 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1495 and the names of the automatically generated variables have changed.
  1496 split_all_tac has moved within claset() from unsafe wrappers to safe
  1497 wrappers, which means that !!-bound variables are split much more
  1498 aggressively, and safe_tac and clarify_tac now split such variables.
  1499 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1500 Note: the same holds for record_split_tac, which does the job of
  1501 split_all_tac for record fields.
  1502 
  1503 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1504 permanently to the default simpset using Addsplits just like
  1505 Addsimps. They can be removed via Delsplits just like
  1506 Delsimps. Lower-case versions are also available.
  1507 
  1508 * HOL/Simplifier: The rule split_if is now part of the default
  1509 simpset. This means that the simplifier will eliminate all occurrences
  1510 of if-then-else in the conclusion of a goal. To prevent this, you can
  1511 either remove split_if completely from the default simpset by
  1512 `Delsplits [split_if]' or remove it in a specific call of the
  1513 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1514 other case splitting rules to/from the default simpset: every datatype
  1515 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1516 t is the name of the datatype).
  1517 
  1518 * Classical reasoner / Simplifier combination: new force_tac (and
  1519 derivatives Force_tac, force) combines rewriting and classical
  1520 reasoning (and whatever other tools) similarly to auto_tac, but is
  1521 aimed to solve the given subgoal completely.
  1522 
  1523 
  1524 *** General ***
  1525 
  1526 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1527 and `goalw': the theory is no longer needed as an explicit argument -
  1528 the current theory context is used; assumptions are no longer returned
  1529 at the ML-level unless one of them starts with ==> or !!; it is
  1530 recommended to convert to these new commands using isatool fixgoal
  1531 (backup your sources first!);
  1532 
  1533 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1534 the current theory context, and 'theory' to lookup stored theories;
  1535 
  1536 * new theory section 'locale' for declaring constants, assumptions and
  1537 definitions that have local scope;
  1538 
  1539 * new theory section 'nonterminals' for purely syntactic types;
  1540 
  1541 * new theory section 'setup' for generic ML setup functions
  1542 (e.g. package initialization);
  1543 
  1544 * the distribution now includes Isabelle icons: see
  1545 lib/logo/isabelle-{small,tiny}.xpm;
  1546 
  1547 * isatool install - install binaries with absolute references to
  1548 ISABELLE_HOME/bin;
  1549 
  1550 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1551 
  1552 * print mode 'emacs' reserved for Isamode;
  1553 
  1554 * support multiple print (ast) translations per constant name;
  1555 
  1556 * theorems involving oracles are now printed with a suffixed [!];
  1557 
  1558 
  1559 *** HOL ***
  1560 
  1561 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1562 
  1563 * HOL/inductive package reorganized and improved: now supports mutual
  1564 definitions such as
  1565 
  1566   inductive EVEN ODD
  1567     intrs
  1568       null "0 : EVEN"
  1569       oddI "n : EVEN ==> Suc n : ODD"
  1570       evenI "n : ODD ==> Suc n : EVEN"
  1571 
  1572 new theorem list "elims" contains an elimination rule for each of the
  1573 recursive sets; inductive definitions now handle disjunctive premises
  1574 correctly (also ZF);
  1575 
  1576 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1577 "mutual_induct" no longer exists - the induction rule is always
  1578 contained in "induct";
  1579 
  1580 
  1581 * HOL/datatype package re-implemented and greatly improved: now
  1582 supports mutually recursive datatypes such as
  1583 
  1584   datatype
  1585     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1586             | SUM ('a aexp) ('a aexp)
  1587             | DIFF ('a aexp) ('a aexp)
  1588             | NUM 'a
  1589   and
  1590     'a bexp = LESS ('a aexp) ('a aexp)
  1591             | AND ('a bexp) ('a bexp)
  1592             | OR ('a bexp) ('a bexp)
  1593 
  1594 as well as indirectly recursive datatypes such as
  1595 
  1596   datatype
  1597     ('a, 'b) term = Var 'a
  1598                   | App 'b ((('a, 'b) term) list)
  1599 
  1600 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1601 induction on mutually / indirectly recursive datatypes.
  1602 
  1603 Primrec equations are now stored in theory and can be accessed via
  1604 <function_name>.simps.
  1605 
  1606 INCOMPATIBILITIES:
  1607 
  1608   - Theories using datatypes must now have theory Datatype as an
  1609     ancestor.
  1610   - The specific <typename>.induct_tac no longer exists - use the
  1611     generic induct_tac instead.
  1612   - natE has been renamed to nat.exhaust - use exhaust_tac
  1613     instead of res_inst_tac ... natE. Note that the variable
  1614     names in nat.exhaust differ from the names in natE, this
  1615     may cause some "fragile" proofs to fail.
  1616   - The theorems split_<typename>_case and split_<typename>_case_asm
  1617     have been renamed to <typename>.split and <typename>.split_asm.
  1618   - Since default sorts of type variables are now handled correctly,
  1619     some datatype definitions may have to be annotated with explicit
  1620     sort constraints.
  1621   - Primrec definitions no longer require function name and type
  1622     of recursive argument.
  1623 
  1624 Consider using isatool fixdatatype to adapt your theories and proof
  1625 scripts to the new package (backup your sources first!).
  1626 
  1627 
  1628 * HOL/record package: considerably improved implementation; now
  1629 includes concrete syntax for record types, terms, updates; theorems
  1630 for surjective pairing and splitting !!-bound record variables; proof
  1631 support is as follows:
  1632 
  1633   1) standard conversions (selectors or updates applied to record
  1634 constructor terms) are part of the standard simpset;
  1635 
  1636   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1637 made part of standard simpset and claset via addIffs;
  1638 
  1639   3) a tactic for record field splitting (record_split_tac) is part of
  1640 the standard claset (addSWrapper);
  1641 
  1642 To get a better idea about these rules you may retrieve them via
  1643 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1644 the name of your record type.
  1645 
  1646 The split tactic 3) conceptually simplifies by the following rule:
  1647 
  1648   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1649 
  1650 Thus any record variable that is bound by meta-all will automatically
  1651 blow up into some record constructor term, consequently the
  1652 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1653 solve record problems automatically.
  1654 
  1655 
  1656 * reorganized the main HOL image: HOL/Integ and String loaded by
  1657 default; theory Main includes everything;
  1658 
  1659 * automatic simplification of integer sums and comparisons, using cancellation;
  1660 
  1661 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1662 
  1663 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1664 
  1665 * many new identities for unions, intersections, set difference, etc.;
  1666 
  1667 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1668 called split_if, split_split, split_sum_case and split_nat_case (to go
  1669 with add/delsplits);
  1670 
  1671 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1672 (?x::unit) = (); this is made part of the default simpset, which COULD
  1673 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1674 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1675 unit_abs_eta_conv is added in order to counter the effect of
  1676 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1677 %u.f();
  1678 
  1679 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1680 makes more sense);
  1681 
  1682 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1683   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1684   disjointness reasoning but breaking a few old proofs.
  1685 
  1686 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1687 to 'converse' from 'inverse' (for compatibility with ZF and some
  1688 literature);
  1689 
  1690 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1691 the well-founded relation;
  1692 
  1693 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1694     Compl A.  The "Compl" syntax remains available as input syntax for this
  1695     release ONLY.
  1696 
  1697 * HOL/Update: new theory of function updates:
  1698     f(a:=b) == %x. if x=a then b else f x
  1699 may also be iterated as in f(a:=b,c:=d,...);
  1700 
  1701 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1702 
  1703 * HOL/List:
  1704   - new function list_update written xs[i:=v] that updates the i-th
  1705     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1706   - new function `upt' written [i..j(] which generates the list
  1707     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1708     bound write [i..j], which is a shorthand for [i..j+1(].
  1709   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1710 
  1711 * HOL/Arith:
  1712   - removed 'pred' (predecessor) function;
  1713   - generalized some theorems about n-1;
  1714   - many new laws about "div" and "mod";
  1715   - new laws about greatest common divisors (see theory ex/Primes);
  1716 
  1717 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1718 instead of "inverse";
  1719 
  1720 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1721   of the multiset ordering;
  1722 
  1723 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1724   (not included by default);
  1725 
  1726 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1727 
  1728 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1729   programs, i.e. different program variables may have different types.
  1730 
  1731 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1732   [previously, this check worked only if the rewrite rule was unconditional]
  1733   Now rew can involve either definitions or equalities (either == or =).
  1734 
  1735 
  1736 *** ZF ***
  1737 
  1738 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1739   only the theorems proved on ZF.ML;
  1740 
  1741 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1742   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1743   disjointness reasoning but breaking a few old proofs.
  1744 
  1745 * ZF/Update: new theory of function updates
  1746     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1747   may also be iterated as in f(a:=b,c:=d,...);
  1748 
  1749 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1750 
  1751 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1752   [previously, this check worked only if the rewrite rule was unconditional]
  1753   Now rew can involve either definitions or equalities (either == or =).
  1754 
  1755 * case_tac provided for compatibility with HOL
  1756     (like the old excluded_middle_tac, but with subgoals swapped)
  1757 
  1758 
  1759 *** Internal programming interfaces ***
  1760 
  1761 * Pure: several new basic modules made available for general use, see
  1762 also src/Pure/README;
  1763 
  1764 * improved the theory data mechanism to support encapsulation (data
  1765 kind name replaced by private Object.kind, acting as authorization
  1766 key); new type-safe user interface via functor TheoryDataFun; generic
  1767 print_data function becomes basically useless;
  1768 
  1769 * removed global_names compatibility flag -- all theory declarations
  1770 are qualified by default;
  1771 
  1772 * module Pure/Syntax now offers quote / antiquote translation
  1773 functions (useful for Hoare logic etc. with implicit dependencies);
  1774 see HOL/ex/Antiquote for an example use;
  1775 
  1776 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1777 cterm -> thm;
  1778 
  1779 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1780 subgoal;
  1781 
  1782 * Display.print_goals function moved to Locale.print_goals;
  1783 
  1784 * standard print function for goals supports current_goals_markers
  1785 variable for marking begin of proof, end of proof, start of goal; the
  1786 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1787 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1788 for example;
  1789 
  1790 
  1791 
  1792 New in Isabelle98 (January 1998)
  1793 --------------------------------
  1794 
  1795 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1796 
  1797 * changed lexical syntax of terms / types: dots made part of long
  1798 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1799 
  1800 * simpset (and claset) reference variable replaced by functions
  1801 simpset / simpset_ref;
  1802 
  1803 * no longer supports theory aliases (via merge) and non-trivial
  1804 implicit merge of thms' signatures;
  1805 
  1806 * most internal names of constants changed due to qualified names;
  1807 
  1808 * changed Pure/Sequence interface (see Pure/seq.ML);
  1809 
  1810 
  1811 *** General Changes ***
  1812 
  1813 * hierachically structured name spaces (for consts, types, axms, thms
  1814 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1815 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1816 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1817 long_names for fully qualified output names; NOTE: ML programs
  1818 (special tactics, packages etc.) referring to internal names may have
  1819 to be adapted to cope with fully qualified names; in case of severe
  1820 backward campatibility problems try setting 'global_names' at compile
  1821 time to have enrything declared within a flat name space; one may also
  1822 fine tune name declarations in theories via the 'global' and 'local'
  1823 section;
  1824 
  1825 * reimplemented the implicit simpset and claset using the new anytype
  1826 data filed in signatures; references simpset:simpset ref etc. are
  1827 replaced by functions simpset:unit->simpset and
  1828 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1829 to patch your ML files accordingly;
  1830 
  1831 * HTML output now includes theory graph data for display with Java
  1832 applet or isatool browser; data generated automatically via isatool
  1833 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1834 
  1835 * defs may now be conditional; improved rewrite_goals_tac to handle
  1836 conditional equations;
  1837 
  1838 * defs now admits additional type arguments, using TYPE('a) syntax;
  1839 
  1840 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1841 creates a new theory node; implicit merge of thms' signatures is
  1842 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1843 transfer:theory->thm->thm in (rare) cases;
  1844 
  1845 * improved handling of draft signatures / theories; draft thms (and
  1846 ctyps, cterms) are automatically promoted to real ones;
  1847 
  1848 * slightly changed interfaces for oracles: admit many per theory, named
  1849 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1850 
  1851 * print_goals: optional output of const types (set show_consts and
  1852 show_types);
  1853 
  1854 * improved output of warnings (###) and errors (***);
  1855 
  1856 * subgoal_tac displays a warning if the new subgoal has type variables;
  1857 
  1858 * removed old README and Makefiles;
  1859 
  1860 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1861 
  1862 * removed obsolete init_pps and init_database;
  1863 
  1864 * deleted the obsolete tactical STATE, which was declared by
  1865     fun STATE tacfun st = tacfun st st;
  1866 
  1867 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1868 (which abbreviates $HOME);
  1869 
  1870 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1871 use isatool fixseq to adapt your ML programs (this works for fully
  1872 qualified references to the Sequence structure only!);
  1873 
  1874 * use_thy no longer requires writable current directory; it always
  1875 reloads .ML *and* .thy file, if either one is out of date;
  1876 
  1877 
  1878 *** Classical Reasoner ***
  1879 
  1880 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1881 tactics that use classical reasoning to simplify a subgoal without
  1882 splitting it into several subgoals;
  1883 
  1884 * Safe_tac: like safe_tac but uses the default claset;
  1885 
  1886 
  1887 *** Simplifier ***
  1888 
  1889 * added simplification meta rules:
  1890     (asm_)(full_)simplify: simpset -> thm -> thm;
  1891 
  1892 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1893 logics (again);
  1894 
  1895 * added prems argument to simplification procedures;
  1896 
  1897 * HOL, FOL, ZF: added infix function `addsplits':
  1898   instead of `<simpset> setloop (split_tac <thms>)'
  1899   you can simply write `<simpset> addsplits <thms>'
  1900 
  1901 
  1902 *** Syntax ***
  1903 
  1904 * TYPE('a) syntax for type reflection terms;
  1905 
  1906 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1907 
  1908 * pretty printer: changed order of mixfix annotation preference (again!);
  1909 
  1910 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1911 
  1912 
  1913 *** HOL ***
  1914 
  1915 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1916   with `addloop' of the simplifier to faciliate case splitting in premises.
  1917 
  1918 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1919 
  1920 * HOL/Auth: new protocol proofs including some for the Internet
  1921   protocol TLS;
  1922 
  1923 * HOL/Map: new theory of `maps' a la VDM;
  1924 
  1925 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1926 cancelling out common nat summands from =, <, <= (in)equalities, or
  1927 differences; simplification procedures nat_cancel_factor for
  1928 cancelling common factor from =, <, <= (in)equalities over natural
  1929 sums; nat_cancel contains both kinds of procedures, it is installed by
  1930 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1931 
  1932 * HOL/simplifier: terms of the form
  1933   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1934   are rewritten to
  1935   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1936   and those of the form
  1937   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1938   are rewritten to
  1939   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1940 
  1941 * HOL/datatype
  1942   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1943 
  1944   P(t_case f1 ... fn x) =
  1945      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1946         ...
  1947        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1948      )
  1949 
  1950   and a theorem `split_t_case_asm' of the form
  1951 
  1952   P(t_case f1 ... fn x) =
  1953     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1954         ...
  1955        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1956      )
  1957   which can be added to a simpset via `addsplits'. The existing theorems
  1958   expand_list_case and expand_option_case have been renamed to
  1959   split_list_case and split_option_case.
  1960 
  1961 * HOL/Arithmetic:
  1962   - `pred n' is automatically converted to `n-1'.
  1963     Users are strongly encouraged not to use `pred' any longer,
  1964     because it will disappear altogether at some point.
  1965   - Users are strongly encouraged to write "0 < n" rather than
  1966     "n ~= 0". Theorems and proof tools have been modified towards this
  1967     `standard'.
  1968 
  1969 * HOL/Lists:
  1970   the function "set_of_list" has been renamed "set" (and its theorems too);
  1971   the function "nth" now takes its arguments in the reverse order and
  1972   has acquired the infix notation "!" as in "xs!n".
  1973 
  1974 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1975 
  1976 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1977   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1978 
  1979 * HOL/record: extensible records with schematic structural subtyping
  1980 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1981 still lacks various theorems and concrete record syntax;
  1982 
  1983 
  1984 *** HOLCF ***
  1985 
  1986 * removed "axioms" and "generated by" sections;
  1987 
  1988 * replaced "ops" section by extended "consts" section, which is capable of
  1989   handling the continuous function space "->" directly;
  1990 
  1991 * domain package:
  1992   . proves theorems immediately and stores them in the theory,
  1993   . creates hierachical name space,
  1994   . now uses normal mixfix annotations (instead of cinfix...),
  1995   . minor changes to some names and values (for consistency),
  1996   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1997   . separator between mutual domain defs: changed "," to "and",
  1998   . improved handling of sort constraints;  now they have to
  1999     appear on the left-hand side of the equations only;
  2000 
  2001 * fixed LAM <x,y,zs>.b syntax;
  2002 
  2003 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2004 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2005 
  2006 
  2007 *** FOL and ZF ***
  2008 
  2009 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2010   with `addloop' of the simplifier to faciliate case splitting in premises.
  2011 
  2012 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2013 in HOL, they strip ALL and --> from proved theorems;
  2014 
  2015 
  2016 
  2017 New in Isabelle94-8 (May 1997)
  2018 ------------------------------
  2019 
  2020 *** General Changes ***
  2021 
  2022 * new utilities to build / run / maintain Isabelle etc. (in parts
  2023 still somewhat experimental); old Makefiles etc. still functional;
  2024 
  2025 * new 'Isabelle System Manual';
  2026 
  2027 * INSTALL text, together with ./configure and ./build scripts;
  2028 
  2029 * reimplemented type inference for greater efficiency, better error
  2030 messages and clean internal interface;
  2031 
  2032 * prlim command for dealing with lots of subgoals (an easier way of
  2033 setting goals_limit);
  2034 
  2035 
  2036 *** Syntax ***
  2037 
  2038 * supports alternative (named) syntax tables (parser and pretty
  2039 printer); internal interface is provided by add_modesyntax(_i);
  2040 
  2041 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2042 be used in conjunction with the Isabelle symbol font; uses the
  2043 "symbols" syntax table;
  2044 
  2045 * added token_translation interface (may translate name tokens in
  2046 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2047 the current print_mode); IMPORTANT: user print translation functions
  2048 are responsible for marking newly introduced bounds
  2049 (Syntax.mark_boundT);
  2050 
  2051 * token translations for modes "xterm" and "xterm_color" that display
  2052 names in bold, underline etc. or colors (which requires a color
  2053 version of xterm);
  2054 
  2055 * infixes may now be declared with names independent of their syntax;
  2056 
  2057 * added typed_print_translation (like print_translation, but may
  2058 access type of constant);
  2059 
  2060 
  2061 *** Classical Reasoner ***
  2062 
  2063 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2064 some limitations.  Blast_tac...
  2065   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2066   + ignores elimination rules that don't have the correct format
  2067         (the conclusion MUST be a formula variable)
  2068   + ignores types, which can make HOL proofs fail
  2069   + rules must not require higher-order unification, e.g. apply_type in ZF
  2070     [message "Function Var's argument not a bound variable" relates to this]
  2071   + its proof strategy is more general but can actually be slower
  2072 
  2073 * substitution with equality assumptions no longer permutes other
  2074 assumptions;
  2075 
  2076 * minor changes in semantics of addafter (now called addaltern); renamed
  2077 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2078 (and access functions for it);
  2079 
  2080 * improved combination of classical reasoner and simplifier:
  2081   + functions for handling clasimpsets
  2082   + improvement of addss: now the simplifier is called _after_ the
  2083     safe steps.
  2084   + safe variant of addss called addSss: uses safe simplifications
  2085     _during_ the safe steps. It is more complete as it allows multiple
  2086     instantiations of unknowns (e.g. with slow_tac).
  2087 
  2088 *** Simplifier ***
  2089 
  2090 * added interface for simplification procedures (functions that
  2091 produce *proven* rewrite rules on the fly, depending on current
  2092 redex);
  2093 
  2094 * ordering on terms as parameter (used for ordered rewriting);
  2095 
  2096 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2097 
  2098 * the solver is now split into a safe and an unsafe part.
  2099 This should be invisible for the normal user, except that the
  2100 functions setsolver and addsolver have been renamed to setSolver and
  2101 addSolver; added safe_asm_full_simp_tac;
  2102 
  2103 
  2104 *** HOL ***
  2105 
  2106 * a generic induction tactic `induct_tac' which works for all datatypes and
  2107 also for type `nat';
  2108 
  2109 * a generic case distinction tactic `exhaust_tac' which works for all
  2110 datatypes and also for type `nat';
  2111 
  2112 * each datatype comes with a function `size';
  2113 
  2114 * patterns in case expressions allow tuple patterns as arguments to
  2115 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2116 
  2117 * primrec now also works with type nat;
  2118 
  2119 * recdef: a new declaration form, allows general recursive functions to be
  2120 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2121 
  2122 * the constant for negation has been renamed from "not" to "Not" to
  2123 harmonize with FOL, ZF, LK, etc.;
  2124 
  2125 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2126 infinite lists;
  2127 
  2128 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2129 
  2130 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2131 problems in commutative rings, using axiomatic type classes for + and *;
  2132 
  2133 * more examples in HOL/MiniML and HOL/Auth;
  2134 
  2135 * more default rewrite rules for quantifiers, union/intersection;
  2136 
  2137 * a new constant `arbitrary == @x.False';
  2138 
  2139 * HOLCF/IOA replaces old HOL/IOA;
  2140 
  2141 * HOLCF changes: derived all rules and arities
  2142   + axiomatic type classes instead of classes
  2143   + typedef instead of faking type definitions
  2144   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2145   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2146   + eliminated the types void, one, tr
  2147   + use unit lift and bool lift (with translations) instead of one and tr
  2148   + eliminated blift from Lift3.thy (use Def instead of blift)
  2149   all eliminated rules are derived as theorems --> no visible changes ;
  2150 
  2151 
  2152 *** ZF ***
  2153 
  2154 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2155 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2156 as ZF_cs addSIs [equalityI];
  2157 
  2158 
  2159 
  2160 New in Isabelle94-7 (November 96)
  2161 ---------------------------------
  2162 
  2163 * allowing negative levels (as offsets) in prlev and choplev;
  2164 
  2165 * super-linear speedup for large simplifications;
  2166 
  2167 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2168 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2169 FAIL); can suppress it using the command Delsimps (ex_simps @
  2170 all_simps); De Morgan laws are also now included, by default;
  2171 
  2172 * improved printing of ==>  :  ~:
  2173 
  2174 * new object-logic "Sequents" adds linear logic, while replacing LK
  2175 and Modal (thanks to Sara Kalvala);
  2176 
  2177 * HOL/Auth: correctness proofs for authentication protocols;
  2178 
  2179 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2180 examples on HOL/Auth);
  2181 
  2182 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2183 the rewriter and classical reasoner simultaneously;
  2184 
  2185 * function uresult no longer returns theorems in "standard" format;
  2186 regain previous version by: val uresult = standard o uresult;
  2187 
  2188 
  2189 
  2190 New in Isabelle94-6
  2191 -------------------
  2192 
  2193 * oracles -- these establish an interface between Isabelle and trusted
  2194 external reasoners, which may deliver results as theorems;
  2195 
  2196 * proof objects (in particular record all uses of oracles);
  2197 
  2198 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2199 
  2200 * "constdefs" section in theory files;
  2201 
  2202 * "primrec" section (HOL) no longer requires names;
  2203 
  2204 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2205 
  2206 
  2207 
  2208 New in Isabelle94-5
  2209 -------------------
  2210 
  2211 * reduced space requirements;
  2212 
  2213 * automatic HTML generation from theories;
  2214 
  2215 * theory files no longer require "..." (quotes) around most types;
  2216 
  2217 * new examples, including two proofs of the Church-Rosser theorem;
  2218 
  2219 * non-curried (1994) version of HOL is no longer distributed;
  2220 
  2221 
  2222 
  2223 New in Isabelle94-4
  2224 -------------------
  2225 
  2226 * greatly reduced space requirements;
  2227 
  2228 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2229 
  2230 * searchable theorem database (see the section "Retrieving theorems" on
  2231 page 8 of the Reference Manual);
  2232 
  2233 * new examples, including Grabczewski's monumental case study of the
  2234 Axiom of Choice;
  2235 
  2236 * The previous version of HOL renamed to Old_HOL;
  2237 
  2238 * The new version of HOL (previously called CHOL) uses a curried syntax
  2239 for functions.  Application looks like f a b instead of f(a,b);
  2240 
  2241 * Mutually recursive inductive definitions finally work in HOL;
  2242 
  2243 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2244 translates to the operator "split";
  2245 
  2246 
  2247 
  2248 New in Isabelle94-3
  2249 -------------------
  2250 
  2251 * new infix operator, addss, allowing the classical reasoner to
  2252 perform simplification at each step of its search.  Example:
  2253         fast_tac (cs addss ss)
  2254 
  2255 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2256 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2257 look like (a,b) instead of <a,b>;
  2258 
  2259 * PLEASE NOTE: CHOL will eventually replace HOL!
  2260 
  2261 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2262 It translates to the operator "split".  A new theory of integers is available;
  2263 
  2264 * In ZF, integer numerals now denote two's-complement binary integers.
  2265 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2266 
  2267 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2268 of the Axiom of Choice;
  2269 
  2270 
  2271 
  2272 New in Isabelle94-2
  2273 -------------------
  2274 
  2275 * Significantly faster resolution;
  2276 
  2277 * the different sections in a .thy file can now be mixed and repeated
  2278 freely;
  2279 
  2280 * Database of theorems for FOL, HOL and ZF.  New
  2281 commands including qed, qed_goal and bind_thm store theorems in the database.
  2282 
  2283 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2284 a given theory (thms_of), or find out what theory a theorem was proved in
  2285 (theory_of_thm);
  2286 
  2287 * Bugs fixed in the inductive definition and datatype packages;
  2288 
  2289 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2290 and HOL_dup_cs obsolete;
  2291 
  2292 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2293 have been removed;
  2294 
  2295 * Simpler definition of function space in ZF;
  2296 
  2297 * new results about cardinal and ordinal arithmetic in ZF;
  2298 
  2299 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2300 types;
  2301 
  2302 
  2303 $Id$