NEWS
author nipkow
Thu Sep 19 16:09:16 2002 +0200 (2002-09-19)
changeset 13570 0d6a0dce3ba3
parent 13550 5a176b8dda84
child 13587 659813a3f879
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: locale specifications now produce predicate definitions
    10 according to the body of text (covering assumptions modulo local
    11 definitions); predicate "loc_axioms" covers newly introduced text,
    12 while "loc" is cumulative wrt. all included locale expressions; the
    13 latter view is presented only on export into the global theory
    14 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    15 on the old view without predicates;
    16 
    17 * Pure: predefined locales "var" and "struct" are useful for sharing
    18 parameters (as in CASL, for example); just specify something like
    19 ``var x + var y + struct M'' as import;
    20 
    21 * Pure: improved thms_containing: proper indexing of facts instead of
    22 raw theorems; check validity of results wrt. current name space;
    23 include local facts of proof configuration (also covers active
    24 locales), cover fixed variables in index; may use "_" in term
    25 specification; an optional limit for the number of printed facts may
    26 be given (the default is 40);
    27 
    28 * Pure: disallow duplicate fact bindings within new-style theory files
    29 (batch-mode only);
    30 
    31 * Provers: improved induct method: assumptions introduced by case
    32 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    33 the goal statement); "foo" still refers to all facts collectively;
    34 
    35 * Provers: the function blast.overloaded has been removed: all constants
    36 are regarded as potentially overloaded, which improves robustness in exchange
    37 for slight decrease in efficiency;
    38 
    39 * Isar: preview of problems to finish 'show' now produce an error
    40 rather than just a warning (in interactive mode);
    41 
    42 
    43 *** HOL ***
    44 
    45 * 'typedef' command has new option "open" to suppress the set
    46 definition;
    47 
    48 * functions Min and Max on finite sets have been introduced (theory
    49 Finite_Set);
    50 
    51 * attribute [symmetric] now works for relations as well; it turns
    52 (x,y) : R^-1 into (y,x) : R, and vice versa;
    53 
    54 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    55   In ProofGeneral the counter example appears in the trace buffer.
    56 
    57 * arith(_tac) does now know about div k and mod k where k is a numeral
    58 of type nat or int. It can solve simple goals like
    59 
    60   "0 < n ==> n div 2 < (n::nat)"
    61 
    62 but fails if divisibility plays a role like in
    63 
    64   "n div 2 + (n+1) div 2 = (n::nat)"
    65 
    66 * simp's arithmetic capabilities have been enhanced a bit: it now
    67 takes ~= in premises into account (by performing a case split);
    68 
    69 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
    70 are distributed over a sum of terms;
    71 
    72 * the simplifier trace now shows the names of the applied rewrite rules
    73 
    74 * Real/HahnBanach: updated and adapted to locales;
    75 
    76 
    77 *** ZF ***
    78 
    79 * ZF/Constructible: consistency proof for AC (Gödel's constructible
    80 universe, etc.);
    81 
    82 * Main ZF: many theories converted to new-style format;
    83 
    84 
    85 *** ML ***
    86 
    87 * Pure: Tactic.prove provides sane interface for internal proofs;
    88 omits the infamous "standard" operation, so this is more appropriate
    89 than prove_goalw_cterm in many situations (e.g. in simprocs);
    90 
    91 * Pure: improved error reporting of simprocs;
    92 
    93 * Provers: Simplifier.simproc(_i) provides sane interface for setting
    94 up simprocs;
    95 
    96 
    97 
    98 New in Isabelle2002 (March 2002)
    99 --------------------------------
   100 
   101 *** Document preparation ***
   102 
   103 * greatly simplified document preparation setup, including more
   104 graceful interpretation of isatool usedir -i/-d/-D options, and more
   105 instructive isatool mkdir; users should basically be able to get
   106 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   107 users may run a separate document processing stage manually like this:
   108 "isatool usedir -D output HOL Test && isatool document Test/output";
   109 
   110 * theory dependency graph may now be incorporated into documents;
   111 isatool usedir -g true will produce session_graph.eps/.pdf for use
   112 with \includegraphics of LaTeX;
   113 
   114 * proper spacing of consecutive markup elements, especially text
   115 blocks after section headings;
   116 
   117 * support bold style (for single symbols only), input syntax is like
   118 this: "\<^bold>\<alpha>" or "\<^bold>A";
   119 
   120 * \<bullet> is now output as bold \cdot by default, which looks much
   121 better in printed text;
   122 
   123 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   124 note that these symbols are currently unavailable in Proof General /
   125 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   126 
   127 * isatool latex no longer depends on changed TEXINPUTS, instead
   128 isatool document copies the Isabelle style files to the target
   129 location;
   130 
   131 
   132 *** Isar ***
   133 
   134 * Pure/Provers: improved proof by cases and induction;
   135   - 'case' command admits impromptu naming of parameters (such as
   136     "case (Suc n)");
   137   - 'induct' method divinates rule instantiation from the inductive
   138     claim; no longer requires excessive ?P bindings for proper
   139     instantiation of cases;
   140   - 'induct' method properly enumerates all possibilities of set/type
   141     rules; as a consequence facts may be also passed through *type*
   142     rules without further ado;
   143   - 'induct' method now derives symbolic cases from the *rulified*
   144     rule (before it used to rulify cases stemming from the internal
   145     atomized version); this means that the context of a non-atomic
   146     statement becomes is included in the hypothesis, avoiding the
   147     slightly cumbersome show "PROP ?case" form;
   148   - 'induct' may now use elim-style induction rules without chaining
   149     facts, using ``missing'' premises from the goal state; this allows
   150     rules stemming from inductive sets to be applied in unstructured
   151     scripts, while still benefitting from proper handling of non-atomic
   152     statements; NB: major inductive premises need to be put first, all
   153     the rest of the goal is passed through the induction;
   154   - 'induct' proper support for mutual induction involving non-atomic
   155     rule statements (uses the new concept of simultaneous goals, see
   156     below);
   157   - append all possible rule selections, but only use the first
   158     success (no backtracking);
   159   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   160   - undeclared rule case names default to numbers 1, 2, 3, ...;
   161   - added 'print_induct_rules' (covered by help item in recent Proof
   162     General versions);
   163   - moved induct/cases attributes to Pure, methods to Provers;
   164   - generic method setup instantiated for FOL and HOL;
   165 
   166 * Pure: support multiple simultaneous goal statements, for example
   167 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   168 meta-level mechanism, this acts as if several individual goals had
   169 been stated separately; in particular common proof methods need to be
   170 repeated in order to cover all claims; note that a single elimination
   171 step is *not* sufficient to establish the two conjunctions, so this
   172 fails:
   173 
   174   assume "A & B" then have A and B ..   (*".." fails*)
   175 
   176 better use "obtain" in situations as above; alternative refer to
   177 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   178 
   179 * Pure: proper integration with ``locales''; unlike the original
   180 version by Florian Kammüller, Isar locales package high-level proof
   181 contexts rather than raw logical ones (e.g. we admit to include
   182 attributes everywhere); operations on locales include merge and
   183 rename; support for implicit arguments (``structures''); simultaneous
   184 type-inference over imports and text; see also HOL/ex/Locales.thy for
   185 some examples;
   186 
   187 * Pure: the following commands have been ``localized'', supporting a
   188 target locale specification "(in name)": 'lemma', 'theorem',
   189 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   190 stored both within the locale and at the theory level (exported and
   191 qualified by the locale name);
   192 
   193 * Pure: theory goals may now be specified in ``long'' form, with
   194 ad-hoc contexts consisting of arbitrary locale elements. for example
   195 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   196 definitions may be given, too); the result is a meta-level rule with
   197 the context elements being discharged in the obvious way;
   198 
   199 * Pure: new proof command 'using' allows to augment currently used
   200 facts after a goal statement ('using' is syntactically analogous to
   201 'apply', but acts on the goal's facts only); this allows chained facts
   202 to be separated into parts given before and after a claim, as in
   203 ``from a and b have C using d and e <proof>'';
   204 
   205 * Pure: renamed "antecedent" case to "rule_context";
   206 
   207 * Pure: new 'judgment' command records explicit information about the
   208 object-logic embedding (used by several tools internally); no longer
   209 use hard-wired "Trueprop";
   210 
   211 * Pure: added 'corollary' command;
   212 
   213 * Pure: fixed 'token_translation' command;
   214 
   215 * Pure: removed obsolete 'exported' attribute;
   216 
   217 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   218 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   219 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   220 
   221 * Pure: method 'atomize' presents local goal premises as object-level
   222 statements (atomic meta-level propositions); setup controlled via
   223 rewrite rules declarations of 'atomize' attribute; example
   224 application: 'induct' method with proper rule statements in improper
   225 proof *scripts*;
   226 
   227 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   228 now consider the syntactic context of assumptions, giving a better
   229 chance to get type-inference of the arguments right (this is
   230 especially important for locales);
   231 
   232 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   233 mode;
   234 
   235 * Pure/obtain: the formal conclusion "thesis", being marked as
   236 ``internal'', may no longer be reference directly in the text;
   237 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   238 situations;
   239 
   240 * Pure: generic 'sym' attribute which declares a rule both as pure
   241 'elim?' and for the 'symmetric' operation;
   242 
   243 * Pure: marginal comments ``--'' may now occur just anywhere in the
   244 text; the fixed correlation with particular command syntax has been
   245 discontinued;
   246 
   247 * Pure: new method 'rules' is particularly well-suited for proof
   248 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   249 but often produces more compact proof terms with less detours;
   250 
   251 * Pure/Provers/classical: simplified integration with pure rule
   252 attributes and methods; the classical "intro?/elim?/dest?"
   253 declarations coincide with the pure ones; the "rule" method no longer
   254 includes classically swapped intros; "intro" and "elim" methods no
   255 longer pick rules from the context; also got rid of ML declarations
   256 AddXIs/AddXEs/AddXDs; all of this has some potential for
   257 INCOMPATIBILITY;
   258 
   259 * Provers/classical: attribute 'swapped' produces classical inversions
   260 of introduction rules;
   261 
   262 * Provers/simplifier: 'simplified' attribute may refer to explicit
   263 rules instead of full simplifier context; 'iff' attribute handles
   264 conditional rules;
   265 
   266 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   267 
   268 * HOL: 'recdef' now fails on unfinished automated proofs, use
   269 "(permissive)" option to recover old behavior;
   270 
   271 * HOL: 'inductive' no longer features separate (collective) attributes
   272 for 'intros' (was found too confusing);
   273 
   274 * HOL: properly declared induction rules less_induct and
   275 wf_induct_rule;
   276 
   277 
   278 *** HOL ***
   279 
   280 * HOL: moved over to sane numeral syntax; the new policy is as
   281 follows:
   282 
   283   - 0 and 1 are polymorphic constants, which are defined on any
   284   numeric type (nat, int, real etc.);
   285 
   286   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   287   binary representation internally;
   288 
   289   - type nat has special constructor Suc, and generally prefers Suc 0
   290   over 1::nat and Suc (Suc 0) over 2::nat;
   291 
   292 This change may cause significant problems of INCOMPATIBILITY; here
   293 are some hints on converting existing sources:
   294 
   295   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   296   entities, so expressions involving "-" (unary or binary minus) need
   297   to be spaced properly;
   298 
   299   - existing occurrences of "1" may need to be constraint "1::nat" or
   300   even replaced by Suc 0; similar for old "2";
   301 
   302   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   303 
   304   - remove all special provisions on numerals in proofs;
   305 
   306 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   307 representation (depends on bin_arith_simps in the default context);
   308 
   309 * HOL: symbolic syntax for x^2 (numeral 2);
   310 
   311 * HOL: the class of all HOL types is now called "type" rather than
   312 "term"; INCOMPATIBILITY, need to adapt references to this type class
   313 in axclass/classes, instance/arities, and (usually rare) occurrences
   314 in typings (of consts etc.); internally the class is called
   315 "HOL.type", ML programs should refer to HOLogic.typeS;
   316 
   317 * HOL/record package improvements:
   318   - new derived operations "fields" to build a partial record section,
   319     "extend" to promote a fixed record to a record scheme, and
   320     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   321     declared as simp by default;
   322   - shared operations ("more", "fields", etc.) now need to be always
   323     qualified) --- potential INCOMPATIBILITY;
   324   - removed "make_scheme" operations (use "make" with "extend") --
   325     INCOMPATIBILITY;
   326   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   327   - provides cases/induct rules for use with corresponding Isar
   328     methods (for concrete records, record schemes, concrete more
   329     parts, and schematic more parts -- in that order);
   330   - internal definitions directly based on a light-weight abstract
   331     theory of product types over typedef rather than datatype;
   332 
   333 * HOL: generic code generator for generating executable ML code from
   334 specifications; specific support for HOL constructs such as inductive
   335 datatypes and sets, as well as recursive functions; can be invoked
   336 via 'generate_code' theory section;
   337 
   338 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   339 
   340 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   341 (beware of argument permutation!);
   342 
   343 * HOL: linorder_less_split superseded by linorder_cases;
   344 
   345 * HOL/List: "nodups" renamed to "distinct";
   346 
   347 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   348 to peripheral theory "Hilbert_Choice";
   349 
   350 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   351 in this (rare) case use:
   352 
   353   delSWrapper "split_all_tac"
   354   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   355 
   356 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   357 MAY FAIL;
   358 
   359 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   360 Isabelle's type classes, ^ on functions and relations has too general
   361 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   362 necessary to attach explicit type constraints;
   363 
   364 * HOL/Relation: the prefix name of the infix "O" has been changed from
   365 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   366 renamed accordingly (eg "compI" -> "rel_compI").
   367 
   368 * HOL: syntax translations now work properly with numerals and records
   369 expressions;
   370 
   371 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   372 of "lam" -- INCOMPATIBILITY;
   373 
   374 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   375 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   376 renamed "Product_Type.unit";
   377 
   378 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   379 
   380 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   381 the "cases" method);
   382 
   383 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   384 Florian Kammüller);
   385 
   386 * HOL/IMP: updated and converted to new-style theory format; several
   387 parts turned into readable document, with proper Isar proof texts and
   388 some explanations (by Gerwin Klein);
   389 
   390 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   391 
   392 * HOL-Hyperreal is now a logic image;
   393 
   394 
   395 *** HOLCF ***
   396 
   397 * Isar: consts/constdefs supports mixfix syntax for continuous
   398 operations;
   399 
   400 * Isar: domain package adapted to new-style theory format, e.g. see
   401 HOLCF/ex/Dnat.thy;
   402 
   403 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   404 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   405 lift.induct_tac, always use UU instead of Undef;
   406 
   407 * HOLCF/IMP: updated and converted to new-style theory;
   408 
   409 
   410 *** ZF ***
   411 
   412 * Isar: proper integration of logic-specific tools and packages,
   413 including theory commands '(co)inductive', '(co)datatype',
   414 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   415 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   416 
   417 * theory Main no longer includes AC; for the Axiom of Choice, base
   418 your theory on Main_ZFC;
   419 
   420 * the integer library now covers quotients and remainders, with many
   421 laws relating division to addition, multiplication, etc.;
   422 
   423 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   424 typeless version of the formalism;
   425 
   426 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   427 format;
   428 
   429 * ZF/Induct: new directory for examples of inductive definitions,
   430 including theory Multiset for multiset orderings; converted to
   431 new-style theory format;
   432 
   433 * ZF: many new theorems about lists, ordinals, etc.;
   434 
   435 
   436 *** General ***
   437 
   438 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   439 variable proof controls level of detail: 0 = no proofs (only oracle
   440 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   441 also ref manual for further ML interfaces;
   442 
   443 * Pure/axclass: removed obsolete ML interface
   444 goal_subclass/goal_arity;
   445 
   446 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   447 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   448 separate tokens, so expressions involving minus need to be spaced
   449 properly;
   450 
   451 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   452 rather than "infixl" or "infixr";
   453 
   454 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   455 sort constraint specifications in type inference; e.g. "x::_::foo"
   456 ensures that the type of "x" is of sort "foo" (but not necessarily a
   457 type variable);
   458 
   459 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   460 control output of nested => (types); the default behavior is
   461 "type_brackets";
   462 
   463 * Pure/syntax: builtin parse translation for "_constify" turns valued
   464 tokens into AST constants;
   465 
   466 * Pure/syntax: prefer later declarations of translations and print
   467 translation functions; potential INCOMPATIBILITY: need to reverse
   468 multiple declarations for same syntax element constant;
   469 
   470 * Pure/show_hyps reset by default (in accordance to existing Isar
   471 practice);
   472 
   473 * Provers/classical: renamed addaltern to addafter, addSaltern to
   474 addSafter;
   475 
   476 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   477 as well;
   478 
   479 * system: tested support for MacOS X; should be able to get Isabelle +
   480 Proof General to work in a plain Terminal after installing Poly/ML
   481 (e.g. from the Isabelle distribution area) and GNU bash alone
   482 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   483 support requires further installations, e.g. from
   484 http://fink.sourceforge.net/);
   485 
   486 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   487 
   488 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   489 of 40 MB), cf. ML_OPTIONS;
   490 
   491 * system: Proof General keywords specification is now part of the
   492 Isabelle distribution (see etc/isar-keywords.el);
   493 
   494 * system: support for persistent Proof General sessions (refrain from
   495 outdating all loaded theories on startup); user may create writable
   496 logic images like this: ``isabelle -q HOL Test'';
   497 
   498 * system: smart selection of Isabelle process versus Isabelle
   499 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   500 run both "isabelle" and "Isabelle" even if file names are badly
   501 damaged (executable inspects the case of the first letter of its own
   502 name); added separate "isabelle-process" and "isabelle-interface";
   503 
   504 * system: refrain from any attempt at filtering input streams; no
   505 longer support ``8bit'' encoding of old isabelle font, instead proper
   506 iso-latin characters may now be used; the related isatools
   507 "symbolinput" and "nonascii" have disappeared as well;
   508 
   509 * system: removed old "xterm" interface (the print modes "xterm" and
   510 "xterm_color" are still available for direct use in a suitable
   511 terminal);
   512 
   513 
   514 
   515 New in Isabelle99-2 (February 2001)
   516 -----------------------------------
   517 
   518 *** Overview of INCOMPATIBILITIES ***
   519 
   520 * HOL: please note that theories in the Library and elsewhere often use the
   521 new-style (Isar) format; to refer to their theorems in an ML script you must
   522 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   523 
   524 * HOL: inductive package no longer splits induction rule aggressively,
   525 but only as far as specified by the introductions given; the old
   526 format may be recovered via ML function complete_split_rule or attribute
   527 'split_rule (complete)';
   528 
   529 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   530 gfp_Tarski to gfp_unfold;
   531 
   532 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   533 
   534 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   535 relation); infix "^^" has been renamed "``"; infix "``" has been
   536 renamed "`"; "univalent" has been renamed "single_valued";
   537 
   538 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   539 operation;
   540 
   541 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   542 
   543 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   544 
   545 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   546 consequence, it is no longer monotonic wrt. the local goal context
   547 (which is now passed through the inductive cases);
   548 
   549 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   550 \<gg> to \<ggreater>;
   551 
   552 
   553 *** Document preparation ***
   554 
   555 * \isabellestyle{NAME} selects version of Isabelle output (currently
   556 available: are "it" for near math-mode best-style output, "sl" for
   557 slanted text style, and "tt" for plain type-writer; if no
   558 \isabellestyle command is given, output is according to slanted
   559 type-writer);
   560 
   561 * support sub/super scripts (for single symbols only), input syntax is
   562 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   563 
   564 * some more standard symbols; see Appendix A of the system manual for
   565 the complete list of symbols defined in isabellesym.sty;
   566 
   567 * improved isabelle style files; more abstract symbol implementation
   568 (should now use \isamath{...} and \isatext{...} in custom symbol
   569 definitions);
   570 
   571 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   572 state; Note that presentation of goal states does not conform to
   573 actual human-readable proof documents.  Please do not include goal
   574 states into document output unless you really know what you are doing!
   575 
   576 * proper indentation of antiquoted output with proportional LaTeX
   577 fonts;
   578 
   579 * no_document ML operator temporarily disables LaTeX document
   580 generation;
   581 
   582 * isatool unsymbolize tunes sources for plain ASCII communication;
   583 
   584 
   585 *** Isar ***
   586 
   587 * Pure: Isar now suffers initial goal statements to contain unbound
   588 schematic variables (this does not conform to actual readable proof
   589 documents, due to unpredictable outcome and non-compositional proof
   590 checking); users who know what they are doing may use schematic goals
   591 for Prolog-style synthesis of proven results;
   592 
   593 * Pure: assumption method (an implicit finishing) now handles actual
   594 rules as well;
   595 
   596 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   597 initial goal, declare "that" only as Pure intro (only for single
   598 steps); the "that" rule assumption may now be involved in implicit
   599 finishing, thus ".." becomes a feasible for trivial obtains;
   600 
   601 * Pure: default proof step now includes 'intro_classes'; thus trivial
   602 instance proofs may be performed by "..";
   603 
   604 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   605 statements as well;
   606 
   607 * Pure: more robust selection of calculational rules;
   608 
   609 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   610 rule (as well as the assumption rule);
   611 
   612 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   613 lemmas, using the graph browser tool;
   614 
   615 * Pure: predict failure of "show" in interactive mode;
   616 
   617 * Pure: 'thms_containing' now takes actual terms as arguments;
   618 
   619 * HOL: improved method 'induct' --- now handles non-atomic goals
   620 (potential INCOMPATIBILITY); tuned error handling;
   621 
   622 * HOL: cases and induct rules now provide explicit hints about the
   623 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   624 any remaining facts are inserted into the goal verbatim;
   625 
   626 * HOL: local contexts (aka cases) may now contain term bindings as
   627 well; the 'cases' and 'induct' methods new provide a ?case binding for
   628 the result to be shown in each case;
   629 
   630 * HOL: added 'recdef_tc' command;
   631 
   632 * isatool convert assists in eliminating legacy ML scripts;
   633 
   634 
   635 *** HOL ***
   636 
   637 * HOL/Library: a collection of generic theories to be used together
   638 with main HOL; the theory loader path already includes this directory
   639 by default; the following existing theories have been moved here:
   640 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   641 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   642 
   643 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   644 modelling and verification task performed in Isabelle/HOL +
   645 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   646 
   647 * HOL/Algebra: special summation operator SUM no longer exists, it has
   648 been replaced by setsum; infix 'assoc' now has priority 50 (like
   649 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   650 'domain', this makes the theory consistent with mathematical
   651 literature;
   652 
   653 * HOL basics: added overloaded operations "inverse" and "divide"
   654 (infix "/"), syntax for generic "abs" operation, generic summation
   655 operator \<Sum>;
   656 
   657 * HOL/typedef: simplified package, provide more useful rules (see also
   658 HOL/subset.thy);
   659 
   660 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   661 now expressed as a proper nested rule (old-style tactic scripts may
   662 require atomize_strip_tac to cope with non-atomic premises);
   663 
   664 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   665 to "split_conv" (old name still available for compatibility);
   666 
   667 * HOL: improved concrete syntax for strings (e.g. allows translation
   668 rules with string literals);
   669 
   670 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   671  and Fleuriot's mechanization of analysis, including the transcendental
   672  functions for the reals;
   673 
   674 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   675 
   676 
   677 *** CTT ***
   678 
   679 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   680 "lam" is displayed as TWO lambda-symbols
   681 
   682 * CTT: theory Main now available, containing everything (that is, Bool
   683 and Arith);
   684 
   685 
   686 *** General ***
   687 
   688 * Pure: the Simplifier has been implemented properly as a derived rule
   689 outside of the actual kernel (at last!); the overall performance
   690 penalty in practical applications is about 50%, while reliability of
   691 the Isabelle inference kernel has been greatly improved;
   692 
   693 * print modes "brackets" and "no_brackets" control output of nested =>
   694 (types) and ==> (props); the default behaviour is "brackets";
   695 
   696 * Provers: fast_tac (and friends) now handle actual object-logic rules
   697 as assumptions as well;
   698 
   699 * system: support Poly/ML 4.0;
   700 
   701 * system: isatool install handles KDE version 1 or 2;
   702 
   703 
   704 
   705 New in Isabelle99-1 (October 2000)
   706 ----------------------------------
   707 
   708 *** Overview of INCOMPATIBILITIES ***
   709 
   710 * HOL: simplification of natural numbers is much changed; to partly
   711 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   712 issue the following ML commands:
   713 
   714   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   715   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   716 
   717 * HOL: simplification no longer dives into case-expressions; this is
   718 controlled by "t.weak_case_cong" for each datatype t;
   719 
   720 * HOL: nat_less_induct renamed to less_induct;
   721 
   722 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   723 fixsome to patch .thy and .ML sources automatically;
   724 
   725   select_equality  -> some_equality
   726   select_eq_Ex     -> some_eq_ex
   727   selectI2EX       -> someI2_ex
   728   selectI2         -> someI2
   729   selectI          -> someI
   730   select1_equality -> some1_equality
   731   Eps_sym_eq       -> some_sym_eq_trivial
   732   Eps_eq           -> some_eq_trivial
   733 
   734 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   735 
   736 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   737 instead);
   738 
   739 * HOL: the recursion equations generated by 'recdef' are now called
   740 f.simps instead of f.rules;
   741 
   742 * HOL: qed_spec_mp now also handles bounded ALL as well;
   743 
   744 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   745 sometimes be needed;
   746 
   747 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   748 
   749 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   750 
   751 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   752 product is now "<*>" instead of "Times"; the lexicographic product is
   753 now "<*lex*>" instead of "**";
   754 
   755 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   756 of main HOL, but was unused); better use HOL's datatype package;
   757 
   758 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   759 the old syntax may be recovered as follows:
   760 
   761   syntax (symbols)
   762     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   763       (infixl "\\<oplus>" 100)
   764 
   765 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   766 
   767 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   768 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   769 internally;
   770 
   771 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   772 changed from A/r to A//r;
   773 
   774 * ZF: new treatment of arithmetic (nat & int) may break some old
   775 proofs;
   776 
   777 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   778 rulify -> rule_format, elimify -> elim_format, ...);
   779 
   780 * Isar/Provers: intro/elim/dest attributes changed; renamed
   781 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   782 should have to change intro!! to intro? only); replaced "delrule" by
   783 "rule del";
   784 
   785 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   786 
   787 * Provers: strengthened force_tac by using new first_best_tac;
   788 
   789 * LaTeX document preparation: several changes of isabelle.sty (see
   790 lib/texinputs);
   791 
   792 
   793 *** Document preparation ***
   794 
   795 * formal comments (text blocks etc.) in new-style theories may now
   796 contain antiquotations of thm/prop/term/typ/text to be presented
   797 according to latex print mode; concrete syntax is like this:
   798 @{term[show_types] "f(x) = a + x"};
   799 
   800 * isatool mkdir provides easy setup of Isabelle session directories,
   801 including proper document sources;
   802 
   803 * generated LaTeX sources are now deleted after successful run
   804 (isatool document -c); may retain a copy somewhere else via -D option
   805 of isatool usedir;
   806 
   807 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   808 style files, achieving self-contained LaTeX sources and simplifying
   809 LaTeX debugging;
   810 
   811 * old-style theories now produce (crude) LaTeX output as well;
   812 
   813 * browser info session directories are now self-contained (may be put
   814 on WWW server seperately); improved graphs of nested sessions; removed
   815 graph for 'all sessions';
   816 
   817 * several improvements in isabelle style files; \isabellestyle{it}
   818 produces fake math mode output; \isamarkupheader is now \section by
   819 default; see lib/texinputs/isabelle.sty etc.;
   820 
   821 
   822 *** Isar ***
   823 
   824 * Isar/Pure: local results and corresponding term bindings are now
   825 subject to Hindley-Milner polymorphism (similar to ML); this
   826 accommodates incremental type-inference very nicely;
   827 
   828 * Isar/Pure: new derived language element 'obtain' supports
   829 generalized existence reasoning;
   830 
   831 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   832 support accumulation of results, without applying any rules yet;
   833 useful to collect intermediate results without explicit name
   834 references, and for use with transitivity rules with more than 2
   835 premises;
   836 
   837 * Isar/Pure: scalable support for case-analysis type proofs: new
   838 'case' language element refers to local contexts symbolically, as
   839 produced by certain proof methods; internally, case names are attached
   840 to theorems as "tags";
   841 
   842 * Isar/Pure: theory command 'hide' removes declarations from
   843 class/type/const name spaces;
   844 
   845 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   846 indicate potential overloading;
   847 
   848 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   849 
   850 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   851 "{a,b,c}" instead of {a,b,c};
   852 
   853 * Isar/Pure now provides its own version of intro/elim/dest
   854 attributes; useful for building new logics, but beware of confusion
   855 with the version in Provers/classical;
   856 
   857 * Isar/Pure: the local context of (non-atomic) goals is provided via
   858 case name 'antecedent';
   859 
   860 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   861 to the current context is now done automatically);
   862 
   863 * Isar/Pure: theory command 'method_setup' provides a simple interface
   864 for definining proof methods in ML;
   865 
   866 * Isar/Provers: intro/elim/dest attributes changed; renamed
   867 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   868 most cases, one should have to change intro!! to intro? only);
   869 replaced "delrule" by "rule del";
   870 
   871 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   872 'symmetric' attribute (the latter supercedes [RS sym]);
   873 
   874 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   875 method modifier); 'simp' method: 'only:' modifier removes loopers as
   876 well (including splits);
   877 
   878 * Isar/Provers: Simplifier and Classical methods now support all kind
   879 of modifiers used in the past, including 'cong', 'iff', etc.
   880 
   881 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   882 of Simplifier and Classical reasoner);
   883 
   884 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   885 now support named cases; major packages (inductive, datatype, primrec,
   886 recdef) support case names and properly name parameters;
   887 
   888 * Isar/HOL: new transitivity rules for substitution in inequalities --
   889 monotonicity conditions are extracted to be proven at end of
   890 calculations;
   891 
   892 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   893 method anyway;
   894 
   895 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   896 split_if split_if_asm; datatype package provides theorems foo.splits =
   897 foo.split foo.split_asm for each datatype;
   898 
   899 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   900 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   901 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   902 use "(cases (simplified))" method in proper proof texts);
   903 
   904 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   905 
   906 * Isar: names of theorems etc. may be natural numbers as well;
   907 
   908 * Isar: 'pr' command: optional arguments for goals_limit and
   909 ProofContext.prems_limit; no longer prints theory contexts, but only
   910 proof states;
   911 
   912 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   913 additional print modes to be specified; e.g. "pr(latex)" will print
   914 proof state according to the Isabelle LaTeX style;
   915 
   916 * Isar: improved support for emulating tactic scripts, including proof
   917 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   918 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   919 (for HOL datatypes);
   920 
   921 * Isar: simplified (more robust) goal selection of proof methods: 1st
   922 goal, all goals, or explicit goal specifier (tactic emulation); thus
   923 'proof method scripts' have to be in depth-first order;
   924 
   925 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   926 
   927 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   928 should instead use individual commands for printing items
   929 (print_commands, print_methods etc.);
   930 
   931 * Isar: added 'nothing' --- the empty list of theorems;
   932 
   933 
   934 *** HOL ***
   935 
   936 * HOL/MicroJava: formalization of a fragment of Java, together with a
   937 corresponding virtual machine and a specification of its bytecode
   938 verifier and a lightweight bytecode verifier, including proofs of
   939 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   940 Cornelia Pusch (see also the homepage of project Bali at
   941 http://isabelle.in.tum.de/Bali/);
   942 
   943 * HOL/Algebra: new theory of rings and univariate polynomials, by
   944 Clemens Ballarin;
   945 
   946 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   947 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   948 Rasmussen;
   949 
   950 * HOL/Lattice: fundamental concepts of lattice theory and order
   951 structures, including duals, properties of bounds versus algebraic
   952 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   953 Theorem for complete lattices etc.; may also serve as a demonstration
   954 for abstract algebraic reasoning using axiomatic type classes, and
   955 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   956 
   957 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   958 von Oheimb;
   959 
   960 * HOL/IMPP: extension of IMP with local variables and mutually
   961 recursive procedures, by David von Oheimb;
   962 
   963 * HOL/Lambda: converted into new-style theory and document;
   964 
   965 * HOL/ex/Multiquote: example of multiple nested quotations and
   966 anti-quotations -- basically a generalized version of de-Bruijn
   967 representation; very useful in avoiding lifting of operations;
   968 
   969 * HOL/record: added general record equality rule to simpset; fixed
   970 select-update simplification procedure to handle extended records as
   971 well; admit "r" as field name;
   972 
   973 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   974 other numeric types and also as the identity of groups, rings, etc.;
   975 
   976 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   977 Types nat and int belong to this axclass;
   978 
   979 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   980    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   981    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   982   two terms #m*u and #n*u are replaced by #(m+n)*u
   983     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   984   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   985     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   986 
   987 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   988 powerful prover for predicate logic but knows nothing of clasets; see
   989 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   990 
   991 * HOL: new version of "case_tac" subsumes both boolean case split and
   992 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   993 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   994 
   995 * HOL: simplification no longer dives into case-expressions: only the
   996 selector expression is simplified, but not the remaining arms; to
   997 enable full simplification of case-expressions for datatype t, you may
   998 remove t.weak_case_cong from the simpset, either globally (Delcongs
   999 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1000 
  1001 * HOL/recdef: the recursion equations generated by 'recdef' for
  1002 function 'f' are now called f.simps instead of f.rules; if all
  1003 termination conditions are proved automatically, these simplification
  1004 rules are added to the simpset, as in primrec; rules may be named
  1005 individually as well, resulting in a separate list of theorems for
  1006 each equation;
  1007 
  1008 * HOL/While is a new theory that provides a while-combinator. It
  1009 permits the definition of tail-recursive functions without the
  1010 provision of a termination measure. The latter is necessary once the
  1011 invariant proof rule for while is applied.
  1012 
  1013 * HOL: new (overloaded) notation for the set of elements below/above
  1014 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1015 
  1016 * HOL: theorems impI, allI, ballI bound as "strip";
  1017 
  1018 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1019 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1020 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1021 
  1022 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1023 
  1024 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1025 main HOL, but was unused);
  1026 
  1027 * HOL: fewer consts declared as global (e.g. have to refer to
  1028 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1029 
  1030 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1031 in case of overlap with user translations (e.g. judgements over
  1032 tuples); (note that the underlying logical represenation is still
  1033 bogus);
  1034 
  1035 
  1036 *** ZF ***
  1037 
  1038 * ZF: simplification automatically cancels common terms in arithmetic
  1039 expressions over nat and int;
  1040 
  1041 * ZF: new treatment of nat to minimize type-checking: all operators
  1042 coerce their operands to a natural number using the function natify,
  1043 making the algebraic laws unconditional;
  1044 
  1045 * ZF: as above, for int: operators coerce their operands to an integer
  1046 using the function intify;
  1047 
  1048 * ZF: the integer library now contains many of the usual laws for the
  1049 orderings, including $<=, and monotonicity laws for $+ and $*;
  1050 
  1051 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1052 simplification;
  1053 
  1054 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1055 to the simplifier and classical reasoner simultaneously;
  1056 
  1057 
  1058 *** General ***
  1059 
  1060 * Provers: blast_tac now handles actual object-logic rules as
  1061 assumptions; note that auto_tac uses blast_tac internally as well;
  1062 
  1063 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1064 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1065 
  1066 * Provers: delrules now handles destruct rules as well (no longer need
  1067 explicit make_elim);
  1068 
  1069 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1070   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1071 use instead the strong form,
  1072   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1073 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1074 from destruct-rules;
  1075 
  1076 * Provers: Simplifier.easy_setup provides a fast path to basic
  1077 Simplifier setup for new object-logics;
  1078 
  1079 * Pure: AST translation rules no longer require constant head on LHS;
  1080 
  1081 * Pure: improved name spaces: ambiguous output is qualified; support
  1082 for hiding of names;
  1083 
  1084 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1085 XSYMBOL_HOME; no longer need to do manual configuration in most
  1086 situations;
  1087 
  1088 * system: compression of ML heaps images may now be controlled via -c
  1089 option of isabelle and isatool usedir (currently only observed by
  1090 Poly/ML);
  1091 
  1092 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1093 useful for remote X11);
  1094 
  1095 * system: provide TAGS file for Isabelle sources;
  1096 
  1097 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1098 order;
  1099 
  1100 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1101 timing flag supersedes proof_timing and Toplevel.trace;
  1102 
  1103 * ML: new combinators |>> and |>>> for incremental transformations
  1104 with secondary results (e.g. certain theory extensions):
  1105 
  1106 * ML: PureThy.add_defs gets additional argument to indicate potential
  1107 overloading (usually false);
  1108 
  1109 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1110 results;
  1111 
  1112 
  1113 
  1114 New in Isabelle99 (October 1999)
  1115 --------------------------------
  1116 
  1117 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1118 
  1119 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1120 are no longer simplified.  (This allows the simplifier to unfold recursive
  1121 functional programs.)  To restore the old behaviour, declare
  1122 
  1123     Delcongs [if_weak_cong];
  1124 
  1125 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1126 complement;
  1127 
  1128 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1129 
  1130 * HOL/datatype: mutual_induct_tac no longer exists --
  1131   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1132 
  1133 * HOL/typedef: fixed type inference for representing set; type
  1134 arguments now have to occur explicitly on the rhs as type constraints;
  1135 
  1136 * ZF: The con_defs part of an inductive definition may no longer refer
  1137 to constants declared in the same theory;
  1138 
  1139 * HOL, ZF: the function mk_cases, generated by the inductive
  1140 definition package, has lost an argument.  To simplify its result, it
  1141 uses the default simpset instead of a supplied list of theorems.
  1142 
  1143 * HOL/List: the constructors of type list are now Nil and Cons;
  1144 
  1145 * Simplifier: the type of the infix ML functions
  1146         setSSolver addSSolver setSolver addSolver
  1147 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1148 for packaging solvers. A solver is created via
  1149         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1150 where the string argument is only a comment.
  1151 
  1152 
  1153 *** Proof tools ***
  1154 
  1155 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1156 decision procedure for linear arithmetic. Currently it is used for
  1157 types `nat', `int', and `real' in HOL (see below); it can, should and
  1158 will be instantiated for other types and logics as well.
  1159 
  1160 * The simplifier now accepts rewrite rules with flexible heads, eg
  1161      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1162   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1163   matching.
  1164 
  1165 
  1166 *** General ***
  1167 
  1168 * New Isabelle/Isar subsystem provides an alternative to traditional
  1169 tactical theorem proving; together with the ProofGeneral/isar user
  1170 interface it offers an interactive environment for developing human
  1171 readable proof documents (Isar == Intelligible semi-automated
  1172 reasoning); for further information see isatool doc isar-ref,
  1173 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1174 
  1175 * improved and simplified presentation of theories: better HTML markup
  1176 (including colors), graph views in several sizes; isatool usedir now
  1177 provides a proper interface for user theories (via -P option); actual
  1178 document preparation based on (PDF)LaTeX is available as well (for
  1179 new-style theories only); see isatool doc system for more information;
  1180 
  1181 * native support for Proof General, both for classic Isabelle and
  1182 Isabelle/Isar;
  1183 
  1184 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1185 using the graph browser tool;
  1186 
  1187 * Isabelle manuals now also available as PDF;
  1188 
  1189 * theory loader rewritten from scratch (may not be fully
  1190 bug-compatible); old loadpath variable has been replaced by show_path,
  1191 add_path, del_path, reset_path functions; new operations such as
  1192 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1193 isatool doc ref);
  1194 
  1195 * improved isatool install: option -k creates KDE application icon,
  1196 option -p DIR installs standalone binaries;
  1197 
  1198 * added ML_PLATFORM setting (useful for cross-platform installations);
  1199 more robust handling of platform specific ML images for SML/NJ;
  1200 
  1201 * the settings environment is now statically scoped, i.e. it is never
  1202 created again in sub-processes invoked from isabelle, isatool, or
  1203 Isabelle;
  1204 
  1205 * path element specification '~~' refers to '$ISABELLE_HOME';
  1206 
  1207 * in locales, the "assumes" and "defines" parts may be omitted if
  1208 empty;
  1209 
  1210 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1211 long arrows);
  1212 
  1213 * new print_mode "HTML";
  1214 
  1215 * new flag show_tags controls display of tags of theorems (which are
  1216 basically just comments that may be attached by some tools);
  1217 
  1218 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1219 mode and goal output format:
  1220 
  1221 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1222 244c244
  1223 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1224 ---
  1225 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1226 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1227 181c181
  1228 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1229 ---
  1230 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1231 
  1232 * function bind_thms stores lists of theorems (cf. bind_thm);
  1233 
  1234 * new shorthand tactics ftac, eatac, datac, fatac;
  1235 
  1236 * qed (and friends) now accept "" as result name; in that case the
  1237 theorem is not stored, but proper checks and presentation of the
  1238 result still apply;
  1239 
  1240 * theorem database now also indexes constants "Trueprop", "all",
  1241 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1242 
  1243 
  1244 *** HOL ***
  1245 
  1246 ** HOL arithmetic **
  1247 
  1248 * There are now decision procedures for linear arithmetic over nat and
  1249 int:
  1250 
  1251 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1252 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1253 are treated as atomic; subformulae not involving type `nat' or `int'
  1254 are ignored; quantified subformulae are ignored unless they are
  1255 positive universal or negative existential. The tactic has to be
  1256 invoked by hand and can be a little bit slow. In particular, the
  1257 running time is exponential in the number of occurrences of `min' and
  1258 `max', and `-' on `nat'.
  1259 
  1260 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1261 (negated) (in)equalities among the premises and the conclusion into
  1262 account (i.e. no compound formulae) and does not know about `min' and
  1263 `max', and `-' on `nat'. It is fast and is used automatically by the
  1264 simplifier.
  1265 
  1266 NB: At the moment, these decision procedures do not cope with mixed
  1267 nat/int formulae where the two parts interact, such as `m < n ==>
  1268 int(m) < int(n)'.
  1269 
  1270 * HOL/Numeral provides a generic theory of numerals (encoded
  1271 efficiently as bit strings); setup for types nat/int/real is in place;
  1272 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1273 int, existing theories and proof scripts may require a few additional
  1274 type constraints;
  1275 
  1276 * integer division and remainder can now be performed on constant
  1277 arguments;
  1278 
  1279 * many properties of integer multiplication, division and remainder
  1280 are now available;
  1281 
  1282 * An interface to the Stanford Validity Checker (SVC) is available through the
  1283 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1284 are proved automatically.  SVC must be installed separately, and its results
  1285 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1286 invocation of the underlying oracle).  For SVC see
  1287   http://verify.stanford.edu/SVC
  1288 
  1289 * IsaMakefile: the HOL-Real target now builds an actual image;
  1290 
  1291 
  1292 ** HOL misc **
  1293 
  1294 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1295 (in Isabelle/Isar) -- by Gertrud Bauer;
  1296 
  1297 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1298 analysis for assembly languages with subtypes;
  1299 
  1300 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1301 -- avoids syntactic ambiguities and treats state, transition, and
  1302 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1303 changed syntax and (many) tactics;
  1304 
  1305 * HOL/inductive: Now also handles more general introduction rules such
  1306   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1307   theorems are now maintained within the theory (maintained via the
  1308   "mono" attribute);
  1309 
  1310 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1311   (using function types) such as
  1312 
  1313   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1314 
  1315 * HOL/record: record_simproc (part of the default simpset) takes care
  1316 of selectors applied to updated records; record_split_tac is no longer
  1317 part of the default claset; update_defs may now be removed from the
  1318 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1319 
  1320   claset_ref () := claset() addSWrapper record_split_wrapper;
  1321   Delsimprocs [record_simproc]
  1322 
  1323 * HOL/typedef: fixed type inference for representing set; type
  1324 arguments now have to occur explicitly on the rhs as type constraints;
  1325 
  1326 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1327 names rather than an ML expression;
  1328 
  1329 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1330 supplied later.  Program schemes can be defined, such as
  1331     "While B C s = (if B s then While B C (C s) else s)"
  1332 where the well-founded relation can be chosen after B and C have been given.
  1333 
  1334 * HOL/List: the constructors of type list are now Nil and Cons;
  1335 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1336 course, ML tools referring to List.list.op # etc. have to be adapted;
  1337 
  1338 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1339 disabled by default; run isabelle with option -m HOL to get back to
  1340 the original Gordon/HOL-style output;
  1341 
  1342 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1343 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1344 
  1345 * HOL basic syntax simplified (more orthogonal): all variants of
  1346 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1347 Eps operator is provided as well: "SOME x. P[x]";
  1348 
  1349 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1350 
  1351 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1352 thus available for user theories;
  1353 
  1354 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1355 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1356 time;
  1357 
  1358 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1359 several times and then mp;
  1360 
  1361 
  1362 *** LK ***
  1363 
  1364 * the notation <<...>> is now available as a notation for sequences of
  1365 formulas;
  1366 
  1367 * the simplifier is now installed
  1368 
  1369 * the axiom system has been generalized (thanks to Soren Heilmann)
  1370 
  1371 * the classical reasoner now has a default rule database
  1372 
  1373 
  1374 *** ZF ***
  1375 
  1376 * new primrec section allows primitive recursive functions to be given
  1377 directly (as in HOL) over datatypes and the natural numbers;
  1378 
  1379 * new tactics induct_tac and exhaust_tac for induction (or case
  1380 analysis) over datatypes and the natural numbers;
  1381 
  1382 * the datatype declaration of type T now defines the recursor T_rec;
  1383 
  1384 * simplification automatically does freeness reasoning for datatype
  1385 constructors;
  1386 
  1387 * automatic type-inference, with AddTCs command to insert new
  1388 type-checking rules;
  1389 
  1390 * datatype introduction rules are now added as Safe Introduction rules
  1391 to the claset;
  1392 
  1393 * the syntax "if P then x else y" is now available in addition to
  1394 if(P,x,y);
  1395 
  1396 
  1397 *** Internal programming interfaces ***
  1398 
  1399 * tuned simplifier trace output; new flag debug_simp;
  1400 
  1401 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1402 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1403 
  1404 * AxClass.axclass_tac lost the theory argument;
  1405 
  1406 * tuned current_goals_markers semantics: begin / end goal avoids
  1407 printing empty lines;
  1408 
  1409 * removed prs and prs_fn hook, which was broken because it did not
  1410 include \n in its semantics, forcing writeln to add one
  1411 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1412 string -> unit if you really want to output text without newline;
  1413 
  1414 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1415 plain output, interface builders may have to enable 'isabelle_font'
  1416 mode to get Isabelle font glyphs as before;
  1417 
  1418 * refined token_translation interface; INCOMPATIBILITY: output length
  1419 now of type real instead of int;
  1420 
  1421 * theory loader actions may be traced via new ThyInfo.add_hook
  1422 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1423 your own database of information attached to *whole* theories -- as
  1424 opposed to intra-theory data slots offered via TheoryDataFun;
  1425 
  1426 * proper handling of dangling sort hypotheses (at last!);
  1427 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1428 extra sort hypotheses that can be witnessed from the type signature;
  1429 the force_strip_shyps flag is gone, any remaining shyps are simply
  1430 left in the theorem (with a warning issued by strip_shyps_warning);
  1431 
  1432 
  1433 
  1434 New in Isabelle98-1 (October 1998)
  1435 ----------------------------------
  1436 
  1437 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1438 
  1439 * several changes of automated proof tools;
  1440 
  1441 * HOL: major changes to the inductive and datatype packages, including
  1442 some minor incompatibilities of theory syntax;
  1443 
  1444 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1445 called `inj_on';
  1446 
  1447 * HOL: removed duplicate thms in Arith:
  1448   less_imp_add_less  should be replaced by  trans_less_add1
  1449   le_imp_add_le      should be replaced by  trans_le_add1
  1450 
  1451 * HOL: unary minus is now overloaded (new type constraints may be
  1452 required);
  1453 
  1454 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1455 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1456 now taken as an integer constant.
  1457 
  1458 * Pure: ML function 'theory_of' renamed to 'theory';
  1459 
  1460 
  1461 *** Proof tools ***
  1462 
  1463 * Simplifier:
  1464   1. Asm_full_simp_tac is now more aggressive.
  1465      1. It will sometimes reorient premises if that increases their power to
  1466         simplify.
  1467      2. It does no longer proceed strictly from left to right but may also
  1468         rotate premises to achieve further simplification.
  1469      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1470      old Asm_full_simp_tac in that it does not rotate premises.
  1471   2. The simplifier now knows a little bit about nat-arithmetic.
  1472 
  1473 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1474 allows for selected deletion of wrappers, by introduction of names for
  1475 wrapper functionals.  This implies that addbefore, addSbefore,
  1476 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1477 and that adding two tactics with the same name overwrites the first
  1478 one (emitting a warning).
  1479   type wrapper = (int -> tactic) -> (int -> tactic)
  1480   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1481   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1482   delWrapper, delSWrapper: claset *  string            -> claset
  1483   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1484 
  1485 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1486 semantics; addbefore now affects only the unsafe part of step_tac
  1487 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1488 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1489 by Force_tac;
  1490 
  1491 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1492 compWrapper; added safe wrapper (and access functions for it);
  1493 
  1494 * HOL/split_all_tac is now much faster and fails if there is nothing
  1495 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1496 and the names of the automatically generated variables have changed.
  1497 split_all_tac has moved within claset() from unsafe wrappers to safe
  1498 wrappers, which means that !!-bound variables are split much more
  1499 aggressively, and safe_tac and clarify_tac now split such variables.
  1500 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1501 Note: the same holds for record_split_tac, which does the job of
  1502 split_all_tac for record fields.
  1503 
  1504 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1505 permanently to the default simpset using Addsplits just like
  1506 Addsimps. They can be removed via Delsplits just like
  1507 Delsimps. Lower-case versions are also available.
  1508 
  1509 * HOL/Simplifier: The rule split_if is now part of the default
  1510 simpset. This means that the simplifier will eliminate all occurrences
  1511 of if-then-else in the conclusion of a goal. To prevent this, you can
  1512 either remove split_if completely from the default simpset by
  1513 `Delsplits [split_if]' or remove it in a specific call of the
  1514 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1515 other case splitting rules to/from the default simpset: every datatype
  1516 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1517 t is the name of the datatype).
  1518 
  1519 * Classical reasoner / Simplifier combination: new force_tac (and
  1520 derivatives Force_tac, force) combines rewriting and classical
  1521 reasoning (and whatever other tools) similarly to auto_tac, but is
  1522 aimed to solve the given subgoal completely.
  1523 
  1524 
  1525 *** General ***
  1526 
  1527 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1528 and `goalw': the theory is no longer needed as an explicit argument -
  1529 the current theory context is used; assumptions are no longer returned
  1530 at the ML-level unless one of them starts with ==> or !!; it is
  1531 recommended to convert to these new commands using isatool fixgoal
  1532 (backup your sources first!);
  1533 
  1534 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1535 the current theory context, and 'theory' to lookup stored theories;
  1536 
  1537 * new theory section 'locale' for declaring constants, assumptions and
  1538 definitions that have local scope;
  1539 
  1540 * new theory section 'nonterminals' for purely syntactic types;
  1541 
  1542 * new theory section 'setup' for generic ML setup functions
  1543 (e.g. package initialization);
  1544 
  1545 * the distribution now includes Isabelle icons: see
  1546 lib/logo/isabelle-{small,tiny}.xpm;
  1547 
  1548 * isatool install - install binaries with absolute references to
  1549 ISABELLE_HOME/bin;
  1550 
  1551 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1552 
  1553 * print mode 'emacs' reserved for Isamode;
  1554 
  1555 * support multiple print (ast) translations per constant name;
  1556 
  1557 * theorems involving oracles are now printed with a suffixed [!];
  1558 
  1559 
  1560 *** HOL ***
  1561 
  1562 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1563 
  1564 * HOL/inductive package reorganized and improved: now supports mutual
  1565 definitions such as
  1566 
  1567   inductive EVEN ODD
  1568     intrs
  1569       null "0 : EVEN"
  1570       oddI "n : EVEN ==> Suc n : ODD"
  1571       evenI "n : ODD ==> Suc n : EVEN"
  1572 
  1573 new theorem list "elims" contains an elimination rule for each of the
  1574 recursive sets; inductive definitions now handle disjunctive premises
  1575 correctly (also ZF);
  1576 
  1577 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1578 "mutual_induct" no longer exists - the induction rule is always
  1579 contained in "induct";
  1580 
  1581 
  1582 * HOL/datatype package re-implemented and greatly improved: now
  1583 supports mutually recursive datatypes such as
  1584 
  1585   datatype
  1586     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1587             | SUM ('a aexp) ('a aexp)
  1588             | DIFF ('a aexp) ('a aexp)
  1589             | NUM 'a
  1590   and
  1591     'a bexp = LESS ('a aexp) ('a aexp)
  1592             | AND ('a bexp) ('a bexp)
  1593             | OR ('a bexp) ('a bexp)
  1594 
  1595 as well as indirectly recursive datatypes such as
  1596 
  1597   datatype
  1598     ('a, 'b) term = Var 'a
  1599                   | App 'b ((('a, 'b) term) list)
  1600 
  1601 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1602 induction on mutually / indirectly recursive datatypes.
  1603 
  1604 Primrec equations are now stored in theory and can be accessed via
  1605 <function_name>.simps.
  1606 
  1607 INCOMPATIBILITIES:
  1608 
  1609   - Theories using datatypes must now have theory Datatype as an
  1610     ancestor.
  1611   - The specific <typename>.induct_tac no longer exists - use the
  1612     generic induct_tac instead.
  1613   - natE has been renamed to nat.exhaust - use exhaust_tac
  1614     instead of res_inst_tac ... natE. Note that the variable
  1615     names in nat.exhaust differ from the names in natE, this
  1616     may cause some "fragile" proofs to fail.
  1617   - The theorems split_<typename>_case and split_<typename>_case_asm
  1618     have been renamed to <typename>.split and <typename>.split_asm.
  1619   - Since default sorts of type variables are now handled correctly,
  1620     some datatype definitions may have to be annotated with explicit
  1621     sort constraints.
  1622   - Primrec definitions no longer require function name and type
  1623     of recursive argument.
  1624 
  1625 Consider using isatool fixdatatype to adapt your theories and proof
  1626 scripts to the new package (backup your sources first!).
  1627 
  1628 
  1629 * HOL/record package: considerably improved implementation; now
  1630 includes concrete syntax for record types, terms, updates; theorems
  1631 for surjective pairing and splitting !!-bound record variables; proof
  1632 support is as follows:
  1633 
  1634   1) standard conversions (selectors or updates applied to record
  1635 constructor terms) are part of the standard simpset;
  1636 
  1637   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1638 made part of standard simpset and claset via addIffs;
  1639 
  1640   3) a tactic for record field splitting (record_split_tac) is part of
  1641 the standard claset (addSWrapper);
  1642 
  1643 To get a better idea about these rules you may retrieve them via
  1644 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1645 the name of your record type.
  1646 
  1647 The split tactic 3) conceptually simplifies by the following rule:
  1648 
  1649   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1650 
  1651 Thus any record variable that is bound by meta-all will automatically
  1652 blow up into some record constructor term, consequently the
  1653 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1654 solve record problems automatically.
  1655 
  1656 
  1657 * reorganized the main HOL image: HOL/Integ and String loaded by
  1658 default; theory Main includes everything;
  1659 
  1660 * automatic simplification of integer sums and comparisons, using cancellation;
  1661 
  1662 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1663 
  1664 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1665 
  1666 * many new identities for unions, intersections, set difference, etc.;
  1667 
  1668 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1669 called split_if, split_split, split_sum_case and split_nat_case (to go
  1670 with add/delsplits);
  1671 
  1672 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1673 (?x::unit) = (); this is made part of the default simpset, which COULD
  1674 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1675 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1676 unit_abs_eta_conv is added in order to counter the effect of
  1677 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1678 %u.f();
  1679 
  1680 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1681 makes more sense);
  1682 
  1683 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1684   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1685   disjointness reasoning but breaking a few old proofs.
  1686 
  1687 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1688 to 'converse' from 'inverse' (for compatibility with ZF and some
  1689 literature);
  1690 
  1691 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1692 the well-founded relation;
  1693 
  1694 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1695     Compl A.  The "Compl" syntax remains available as input syntax for this
  1696     release ONLY.
  1697 
  1698 * HOL/Update: new theory of function updates:
  1699     f(a:=b) == %x. if x=a then b else f x
  1700 may also be iterated as in f(a:=b,c:=d,...);
  1701 
  1702 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1703 
  1704 * HOL/List:
  1705   - new function list_update written xs[i:=v] that updates the i-th
  1706     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1707   - new function `upt' written [i..j(] which generates the list
  1708     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1709     bound write [i..j], which is a shorthand for [i..j+1(].
  1710   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1711 
  1712 * HOL/Arith:
  1713   - removed 'pred' (predecessor) function;
  1714   - generalized some theorems about n-1;
  1715   - many new laws about "div" and "mod";
  1716   - new laws about greatest common divisors (see theory ex/Primes);
  1717 
  1718 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1719 instead of "inverse";
  1720 
  1721 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1722   of the multiset ordering;
  1723 
  1724 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1725   (not included by default);
  1726 
  1727 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1728 
  1729 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1730   programs, i.e. different program variables may have different types.
  1731 
  1732 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1733   [previously, this check worked only if the rewrite rule was unconditional]
  1734   Now rew can involve either definitions or equalities (either == or =).
  1735 
  1736 
  1737 *** ZF ***
  1738 
  1739 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1740   only the theorems proved on ZF.ML;
  1741 
  1742 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1743   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1744   disjointness reasoning but breaking a few old proofs.
  1745 
  1746 * ZF/Update: new theory of function updates
  1747     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1748   may also be iterated as in f(a:=b,c:=d,...);
  1749 
  1750 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1751 
  1752 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1753   [previously, this check worked only if the rewrite rule was unconditional]
  1754   Now rew can involve either definitions or equalities (either == or =).
  1755 
  1756 * case_tac provided for compatibility with HOL
  1757     (like the old excluded_middle_tac, but with subgoals swapped)
  1758 
  1759 
  1760 *** Internal programming interfaces ***
  1761 
  1762 * Pure: several new basic modules made available for general use, see
  1763 also src/Pure/README;
  1764 
  1765 * improved the theory data mechanism to support encapsulation (data
  1766 kind name replaced by private Object.kind, acting as authorization
  1767 key); new type-safe user interface via functor TheoryDataFun; generic
  1768 print_data function becomes basically useless;
  1769 
  1770 * removed global_names compatibility flag -- all theory declarations
  1771 are qualified by default;
  1772 
  1773 * module Pure/Syntax now offers quote / antiquote translation
  1774 functions (useful for Hoare logic etc. with implicit dependencies);
  1775 see HOL/ex/Antiquote for an example use;
  1776 
  1777 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1778 cterm -> thm;
  1779 
  1780 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1781 subgoal;
  1782 
  1783 * Display.print_goals function moved to Locale.print_goals;
  1784 
  1785 * standard print function for goals supports current_goals_markers
  1786 variable for marking begin of proof, end of proof, start of goal; the
  1787 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1788 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1789 for example;
  1790 
  1791 
  1792 
  1793 New in Isabelle98 (January 1998)
  1794 --------------------------------
  1795 
  1796 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1797 
  1798 * changed lexical syntax of terms / types: dots made part of long
  1799 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1800 
  1801 * simpset (and claset) reference variable replaced by functions
  1802 simpset / simpset_ref;
  1803 
  1804 * no longer supports theory aliases (via merge) and non-trivial
  1805 implicit merge of thms' signatures;
  1806 
  1807 * most internal names of constants changed due to qualified names;
  1808 
  1809 * changed Pure/Sequence interface (see Pure/seq.ML);
  1810 
  1811 
  1812 *** General Changes ***
  1813 
  1814 * hierachically structured name spaces (for consts, types, axms, thms
  1815 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1816 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1817 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1818 long_names for fully qualified output names; NOTE: ML programs
  1819 (special tactics, packages etc.) referring to internal names may have
  1820 to be adapted to cope with fully qualified names; in case of severe
  1821 backward campatibility problems try setting 'global_names' at compile
  1822 time to have enrything declared within a flat name space; one may also
  1823 fine tune name declarations in theories via the 'global' and 'local'
  1824 section;
  1825 
  1826 * reimplemented the implicit simpset and claset using the new anytype
  1827 data filed in signatures; references simpset:simpset ref etc. are
  1828 replaced by functions simpset:unit->simpset and
  1829 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1830 to patch your ML files accordingly;
  1831 
  1832 * HTML output now includes theory graph data for display with Java
  1833 applet or isatool browser; data generated automatically via isatool
  1834 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1835 
  1836 * defs may now be conditional; improved rewrite_goals_tac to handle
  1837 conditional equations;
  1838 
  1839 * defs now admits additional type arguments, using TYPE('a) syntax;
  1840 
  1841 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1842 creates a new theory node; implicit merge of thms' signatures is
  1843 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1844 transfer:theory->thm->thm in (rare) cases;
  1845 
  1846 * improved handling of draft signatures / theories; draft thms (and
  1847 ctyps, cterms) are automatically promoted to real ones;
  1848 
  1849 * slightly changed interfaces for oracles: admit many per theory, named
  1850 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1851 
  1852 * print_goals: optional output of const types (set show_consts and
  1853 show_types);
  1854 
  1855 * improved output of warnings (###) and errors (***);
  1856 
  1857 * subgoal_tac displays a warning if the new subgoal has type variables;
  1858 
  1859 * removed old README and Makefiles;
  1860 
  1861 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1862 
  1863 * removed obsolete init_pps and init_database;
  1864 
  1865 * deleted the obsolete tactical STATE, which was declared by
  1866     fun STATE tacfun st = tacfun st st;
  1867 
  1868 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1869 (which abbreviates $HOME);
  1870 
  1871 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1872 use isatool fixseq to adapt your ML programs (this works for fully
  1873 qualified references to the Sequence structure only!);
  1874 
  1875 * use_thy no longer requires writable current directory; it always
  1876 reloads .ML *and* .thy file, if either one is out of date;
  1877 
  1878 
  1879 *** Classical Reasoner ***
  1880 
  1881 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1882 tactics that use classical reasoning to simplify a subgoal without
  1883 splitting it into several subgoals;
  1884 
  1885 * Safe_tac: like safe_tac but uses the default claset;
  1886 
  1887 
  1888 *** Simplifier ***
  1889 
  1890 * added simplification meta rules:
  1891     (asm_)(full_)simplify: simpset -> thm -> thm;
  1892 
  1893 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1894 logics (again);
  1895 
  1896 * added prems argument to simplification procedures;
  1897 
  1898 * HOL, FOL, ZF: added infix function `addsplits':
  1899   instead of `<simpset> setloop (split_tac <thms>)'
  1900   you can simply write `<simpset> addsplits <thms>'
  1901 
  1902 
  1903 *** Syntax ***
  1904 
  1905 * TYPE('a) syntax for type reflection terms;
  1906 
  1907 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1908 
  1909 * pretty printer: changed order of mixfix annotation preference (again!);
  1910 
  1911 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1912 
  1913 
  1914 *** HOL ***
  1915 
  1916 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1917   with `addloop' of the simplifier to faciliate case splitting in premises.
  1918 
  1919 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1920 
  1921 * HOL/Auth: new protocol proofs including some for the Internet
  1922   protocol TLS;
  1923 
  1924 * HOL/Map: new theory of `maps' a la VDM;
  1925 
  1926 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1927 cancelling out common nat summands from =, <, <= (in)equalities, or
  1928 differences; simplification procedures nat_cancel_factor for
  1929 cancelling common factor from =, <, <= (in)equalities over natural
  1930 sums; nat_cancel contains both kinds of procedures, it is installed by
  1931 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1932 
  1933 * HOL/simplifier: terms of the form
  1934   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1935   are rewritten to
  1936   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1937   and those of the form
  1938   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1939   are rewritten to
  1940   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1941 
  1942 * HOL/datatype
  1943   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1944 
  1945   P(t_case f1 ... fn x) =
  1946      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1947         ...
  1948        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1949      )
  1950 
  1951   and a theorem `split_t_case_asm' of the form
  1952 
  1953   P(t_case f1 ... fn x) =
  1954     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1955         ...
  1956        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1957      )
  1958   which can be added to a simpset via `addsplits'. The existing theorems
  1959   expand_list_case and expand_option_case have been renamed to
  1960   split_list_case and split_option_case.
  1961 
  1962 * HOL/Arithmetic:
  1963   - `pred n' is automatically converted to `n-1'.
  1964     Users are strongly encouraged not to use `pred' any longer,
  1965     because it will disappear altogether at some point.
  1966   - Users are strongly encouraged to write "0 < n" rather than
  1967     "n ~= 0". Theorems and proof tools have been modified towards this
  1968     `standard'.
  1969 
  1970 * HOL/Lists:
  1971   the function "set_of_list" has been renamed "set" (and its theorems too);
  1972   the function "nth" now takes its arguments in the reverse order and
  1973   has acquired the infix notation "!" as in "xs!n".
  1974 
  1975 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1976 
  1977 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1978   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1979 
  1980 * HOL/record: extensible records with schematic structural subtyping
  1981 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1982 still lacks various theorems and concrete record syntax;
  1983 
  1984 
  1985 *** HOLCF ***
  1986 
  1987 * removed "axioms" and "generated by" sections;
  1988 
  1989 * replaced "ops" section by extended "consts" section, which is capable of
  1990   handling the continuous function space "->" directly;
  1991 
  1992 * domain package:
  1993   . proves theorems immediately and stores them in the theory,
  1994   . creates hierachical name space,
  1995   . now uses normal mixfix annotations (instead of cinfix...),
  1996   . minor changes to some names and values (for consistency),
  1997   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1998   . separator between mutual domain defs: changed "," to "and",
  1999   . improved handling of sort constraints;  now they have to
  2000     appear on the left-hand side of the equations only;
  2001 
  2002 * fixed LAM <x,y,zs>.b syntax;
  2003 
  2004 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2005 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2006 
  2007 
  2008 *** FOL and ZF ***
  2009 
  2010 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2011   with `addloop' of the simplifier to faciliate case splitting in premises.
  2012 
  2013 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2014 in HOL, they strip ALL and --> from proved theorems;
  2015 
  2016 
  2017 
  2018 New in Isabelle94-8 (May 1997)
  2019 ------------------------------
  2020 
  2021 *** General Changes ***
  2022 
  2023 * new utilities to build / run / maintain Isabelle etc. (in parts
  2024 still somewhat experimental); old Makefiles etc. still functional;
  2025 
  2026 * new 'Isabelle System Manual';
  2027 
  2028 * INSTALL text, together with ./configure and ./build scripts;
  2029 
  2030 * reimplemented type inference for greater efficiency, better error
  2031 messages and clean internal interface;
  2032 
  2033 * prlim command for dealing with lots of subgoals (an easier way of
  2034 setting goals_limit);
  2035 
  2036 
  2037 *** Syntax ***
  2038 
  2039 * supports alternative (named) syntax tables (parser and pretty
  2040 printer); internal interface is provided by add_modesyntax(_i);
  2041 
  2042 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2043 be used in conjunction with the Isabelle symbol font; uses the
  2044 "symbols" syntax table;
  2045 
  2046 * added token_translation interface (may translate name tokens in
  2047 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2048 the current print_mode); IMPORTANT: user print translation functions
  2049 are responsible for marking newly introduced bounds
  2050 (Syntax.mark_boundT);
  2051 
  2052 * token translations for modes "xterm" and "xterm_color" that display
  2053 names in bold, underline etc. or colors (which requires a color
  2054 version of xterm);
  2055 
  2056 * infixes may now be declared with names independent of their syntax;
  2057 
  2058 * added typed_print_translation (like print_translation, but may
  2059 access type of constant);
  2060 
  2061 
  2062 *** Classical Reasoner ***
  2063 
  2064 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2065 some limitations.  Blast_tac...
  2066   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2067   + ignores elimination rules that don't have the correct format
  2068         (the conclusion MUST be a formula variable)
  2069   + ignores types, which can make HOL proofs fail
  2070   + rules must not require higher-order unification, e.g. apply_type in ZF
  2071     [message "Function Var's argument not a bound variable" relates to this]
  2072   + its proof strategy is more general but can actually be slower
  2073 
  2074 * substitution with equality assumptions no longer permutes other
  2075 assumptions;
  2076 
  2077 * minor changes in semantics of addafter (now called addaltern); renamed
  2078 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2079 (and access functions for it);
  2080 
  2081 * improved combination of classical reasoner and simplifier:
  2082   + functions for handling clasimpsets
  2083   + improvement of addss: now the simplifier is called _after_ the
  2084     safe steps.
  2085   + safe variant of addss called addSss: uses safe simplifications
  2086     _during_ the safe steps. It is more complete as it allows multiple
  2087     instantiations of unknowns (e.g. with slow_tac).
  2088 
  2089 *** Simplifier ***
  2090 
  2091 * added interface for simplification procedures (functions that
  2092 produce *proven* rewrite rules on the fly, depending on current
  2093 redex);
  2094 
  2095 * ordering on terms as parameter (used for ordered rewriting);
  2096 
  2097 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2098 
  2099 * the solver is now split into a safe and an unsafe part.
  2100 This should be invisible for the normal user, except that the
  2101 functions setsolver and addsolver have been renamed to setSolver and
  2102 addSolver; added safe_asm_full_simp_tac;
  2103 
  2104 
  2105 *** HOL ***
  2106 
  2107 * a generic induction tactic `induct_tac' which works for all datatypes and
  2108 also for type `nat';
  2109 
  2110 * a generic case distinction tactic `exhaust_tac' which works for all
  2111 datatypes and also for type `nat';
  2112 
  2113 * each datatype comes with a function `size';
  2114 
  2115 * patterns in case expressions allow tuple patterns as arguments to
  2116 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2117 
  2118 * primrec now also works with type nat;
  2119 
  2120 * recdef: a new declaration form, allows general recursive functions to be
  2121 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2122 
  2123 * the constant for negation has been renamed from "not" to "Not" to
  2124 harmonize with FOL, ZF, LK, etc.;
  2125 
  2126 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2127 infinite lists;
  2128 
  2129 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2130 
  2131 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2132 problems in commutative rings, using axiomatic type classes for + and *;
  2133 
  2134 * more examples in HOL/MiniML and HOL/Auth;
  2135 
  2136 * more default rewrite rules for quantifiers, union/intersection;
  2137 
  2138 * a new constant `arbitrary == @x.False';
  2139 
  2140 * HOLCF/IOA replaces old HOL/IOA;
  2141 
  2142 * HOLCF changes: derived all rules and arities
  2143   + axiomatic type classes instead of classes
  2144   + typedef instead of faking type definitions
  2145   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2146   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2147   + eliminated the types void, one, tr
  2148   + use unit lift and bool lift (with translations) instead of one and tr
  2149   + eliminated blift from Lift3.thy (use Def instead of blift)
  2150   all eliminated rules are derived as theorems --> no visible changes ;
  2151 
  2152 
  2153 *** ZF ***
  2154 
  2155 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2156 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2157 as ZF_cs addSIs [equalityI];
  2158 
  2159 
  2160 
  2161 New in Isabelle94-7 (November 96)
  2162 ---------------------------------
  2163 
  2164 * allowing negative levels (as offsets) in prlev and choplev;
  2165 
  2166 * super-linear speedup for large simplifications;
  2167 
  2168 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2169 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2170 FAIL); can suppress it using the command Delsimps (ex_simps @
  2171 all_simps); De Morgan laws are also now included, by default;
  2172 
  2173 * improved printing of ==>  :  ~:
  2174 
  2175 * new object-logic "Sequents" adds linear logic, while replacing LK
  2176 and Modal (thanks to Sara Kalvala);
  2177 
  2178 * HOL/Auth: correctness proofs for authentication protocols;
  2179 
  2180 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2181 examples on HOL/Auth);
  2182 
  2183 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2184 the rewriter and classical reasoner simultaneously;
  2185 
  2186 * function uresult no longer returns theorems in "standard" format;
  2187 regain previous version by: val uresult = standard o uresult;
  2188 
  2189 
  2190 
  2191 New in Isabelle94-6
  2192 -------------------
  2193 
  2194 * oracles -- these establish an interface between Isabelle and trusted
  2195 external reasoners, which may deliver results as theorems;
  2196 
  2197 * proof objects (in particular record all uses of oracles);
  2198 
  2199 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2200 
  2201 * "constdefs" section in theory files;
  2202 
  2203 * "primrec" section (HOL) no longer requires names;
  2204 
  2205 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2206 
  2207 
  2208 
  2209 New in Isabelle94-5
  2210 -------------------
  2211 
  2212 * reduced space requirements;
  2213 
  2214 * automatic HTML generation from theories;
  2215 
  2216 * theory files no longer require "..." (quotes) around most types;
  2217 
  2218 * new examples, including two proofs of the Church-Rosser theorem;
  2219 
  2220 * non-curried (1994) version of HOL is no longer distributed;
  2221 
  2222 
  2223 
  2224 New in Isabelle94-4
  2225 -------------------
  2226 
  2227 * greatly reduced space requirements;
  2228 
  2229 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2230 
  2231 * searchable theorem database (see the section "Retrieving theorems" on
  2232 page 8 of the Reference Manual);
  2233 
  2234 * new examples, including Grabczewski's monumental case study of the
  2235 Axiom of Choice;
  2236 
  2237 * The previous version of HOL renamed to Old_HOL;
  2238 
  2239 * The new version of HOL (previously called CHOL) uses a curried syntax
  2240 for functions.  Application looks like f a b instead of f(a,b);
  2241 
  2242 * Mutually recursive inductive definitions finally work in HOL;
  2243 
  2244 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2245 translates to the operator "split";
  2246 
  2247 
  2248 
  2249 New in Isabelle94-3
  2250 -------------------
  2251 
  2252 * new infix operator, addss, allowing the classical reasoner to
  2253 perform simplification at each step of its search.  Example:
  2254         fast_tac (cs addss ss)
  2255 
  2256 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2257 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2258 look like (a,b) instead of <a,b>;
  2259 
  2260 * PLEASE NOTE: CHOL will eventually replace HOL!
  2261 
  2262 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2263 It translates to the operator "split".  A new theory of integers is available;
  2264 
  2265 * In ZF, integer numerals now denote two's-complement binary integers.
  2266 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2267 
  2268 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2269 of the Axiom of Choice;
  2270 
  2271 
  2272 
  2273 New in Isabelle94-2
  2274 -------------------
  2275 
  2276 * Significantly faster resolution;
  2277 
  2278 * the different sections in a .thy file can now be mixed and repeated
  2279 freely;
  2280 
  2281 * Database of theorems for FOL, HOL and ZF.  New
  2282 commands including qed, qed_goal and bind_thm store theorems in the database.
  2283 
  2284 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2285 a given theory (thms_of), or find out what theory a theorem was proved in
  2286 (theory_of_thm);
  2287 
  2288 * Bugs fixed in the inductive definition and datatype packages;
  2289 
  2290 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2291 and HOL_dup_cs obsolete;
  2292 
  2293 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2294 have been removed;
  2295 
  2296 * Simpler definition of function space in ZF;
  2297 
  2298 * new results about cardinal and ordinal arithmetic in ZF;
  2299 
  2300 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2301 types;
  2302 
  2303 
  2304 $Id$