NEWS
author wenzelm
Fri Mar 08 16:24:06 2002 +0100 (2002-03-08)
changeset 13049 ce180e5b7fa0
parent 13042 d8a345d9e067
child 13158 8e86582a90d1
permissions -rw-r--r--
tuned;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2002 (March 2002)
     6 --------------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir HOL Test && isatool make"; alternatively,
    14 users may run a separate document processing stage manually like this:
    15 "isatool usedir -D output HOL Test && isatool document Test/output";
    16 
    17 * theory dependency graph may now be incorporated into documents;
    18 isatool usedir -g true will produce session_graph.eps/.pdf for use
    19 with \includegraphics of LaTeX;
    20 
    21 * proper spacing of consecutive markup elements, especially text
    22 blocks after section headings;
    23 
    24 * support bold style (for single symbols only), input syntax is like
    25 this: "\<^bold>\<alpha>" or "\<^bold>A";
    26 
    27 * \<bullet> is now output as bold \cdot by default, which looks much
    28 better in printed text;
    29 
    30 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    31 note that these symbols are currently unavailable in Proof General /
    32 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
    33 
    34 * isatool latex no longer depends on changed TEXINPUTS, instead
    35 isatool document copies the Isabelle style files to the target
    36 location;
    37 
    38 
    39 *** Isar ***
    40 
    41 * Pure/Provers: improved proof by cases and induction;
    42   - 'case' command admits impromptu naming of parameters (such as
    43     "case (Suc n)");
    44   - 'induct' method divinates rule instantiation from the inductive
    45     claim; no longer requires excessive ?P bindings for proper
    46     instantiation of cases;
    47   - 'induct' method properly enumerates all possibilities of set/type
    48     rules; as a consequence facts may be also passed through *type*
    49     rules without further ado;
    50   - 'induct' method now derives symbolic cases from the *rulified*
    51     rule (before it used to rulify cases stemming from the internal
    52     atomized version); this means that the context of a non-atomic
    53     statement becomes is included in the hypothesis, avoiding the
    54     slightly cumbersome show "PROP ?case" form;
    55   - 'induct' may now use elim-style induction rules without chaining
    56     facts, using ``missing'' premises from the goal state; this allows
    57     rules stemming from inductive sets to be applied in unstructured
    58     scripts, while still benefitting from proper handling of non-atomic
    59     statements; NB: major inductive premises need to be put first, all
    60     the rest of the goal is passed through the induction;
    61   - 'induct' proper support for mutual induction involving non-atomic
    62     rule statements (uses the new concept of simultaneous goals, see
    63     below);
    64   - append all possible rule selections, but only use the first
    65     success (no backtracking);
    66   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    67   - undeclared rule case names default to numbers 1, 2, 3, ...;
    68   - added 'print_induct_rules' (covered by help item in recent Proof
    69     General versions);
    70   - moved induct/cases attributes to Pure, methods to Provers;
    71   - generic method setup instantiated for FOL and HOL;
    72 
    73 * Pure: support multiple simultaneous goal statements, for example
    74 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    75 meta-level mechanism, this acts as if several individual goals had
    76 been stated separately; in particular common proof methods need to be
    77 repeated in order to cover all claims; note that a single elimination
    78 step is *not* sufficient to establish the two conjunctions, so this
    79 fails:
    80 
    81   assume "A & B" then have A and B ..   (*".." fails*)
    82 
    83 better use "obtain" in situations as above; alternative refer to
    84 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    85 
    86 * Pure: proper integration with ``locales''; unlike the original
    87 version by Florian Kammüller, Isar locales package high-level proof
    88 contexts rather than raw logical ones (e.g. we admit to include
    89 attributes everywhere); operations on locales include merge and
    90 rename; support for implicit arguments (``structures''); simultaneous
    91 type-inference over imports and text; see also HOL/ex/Locales.thy for
    92 some examples;
    93 
    94 * Pure: the following commands have been ``localized'', supporting a
    95 target locale specification "(in name)": 'lemma', 'theorem',
    96 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
    97 stored both within the locale and at the theory level (exported and
    98 qualified by the locale name);
    99 
   100 * Pure: theory goals may now be specified in ``long'' form, with
   101 ad-hoc contexts consisting of arbitrary locale elements. for example
   102 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   103 definitions may be given, too); the result is a meta-level rule with
   104 the context elements being discharged in the obvious way;
   105 
   106 * Pure: new proof command 'using' allows to augment currently used
   107 facts after a goal statement ('using' is syntactically analogous to
   108 'apply', but acts on the goal's facts only); this allows chained facts
   109 to be separated into parts given before and after a claim, as in
   110 ``from a and b have C using d and e <proof>'';
   111 
   112 * Pure: renamed "antecedent" case to "rule_context";
   113 
   114 * Pure: new 'judgment' command records explicit information about the
   115 object-logic embedding (used by several tools internally); no longer
   116 use hard-wired "Trueprop";
   117 
   118 * Pure: added 'corollary' command;
   119 
   120 * Pure: fixed 'token_translation' command;
   121 
   122 * Pure: removed obsolete 'exported' attribute;
   123 
   124 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   125 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   126 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   127 
   128 * Pure: method 'atomize' presents local goal premises as object-level
   129 statements (atomic meta-level propositions); setup controlled via
   130 rewrite rules declarations of 'atomize' attribute; example
   131 application: 'induct' method with proper rule statements in improper
   132 proof *scripts*;
   133 
   134 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   135 now consider the syntactic context of assumptions, giving a better
   136 chance to get type-inference of the arguments right (this is
   137 especially important for locales);
   138 
   139 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   140 mode;
   141 
   142 * Pure/obtain: the formal conclusion "thesis", being marked as
   143 ``internal'', may no longer be reference directly in the text;
   144 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   145 situations;
   146 
   147 * Pure: generic 'sym' attribute which declares a rule both as pure
   148 'elim?' and for the 'symmetric' operation;
   149 
   150 * Pure: marginal comments ``--'' may now occur just anywhere in the
   151 text; the fixed correlation with particular command syntax has been
   152 discontinued;
   153 
   154 * Pure: new method 'rules' is particularly well-suited for proof
   155 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   156 but often produces more compact proof terms with less detours;
   157 
   158 * Pure/Provers/classical: simplified integration with pure rule
   159 attributes and methods; the classical "intro?/elim?/dest?"
   160 declarations coincide with the pure ones; the "rule" method no longer
   161 includes classically swapped intros; "intro" and "elim" methods no
   162 longer pick rules from the context; also got rid of ML declarations
   163 AddXIs/AddXEs/AddXDs; all of this has some potential for
   164 INCOMPATIBILITY;
   165 
   166 * Provers/classical: attribute 'swapped' produces classical inversions
   167 of introduction rules;
   168 
   169 * Provers/simplifier: 'simplified' attribute may refer to explicit
   170 rules instead of full simplifier context; 'iff' attribute handles
   171 conditional rules;
   172 
   173 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   174 
   175 * HOL: 'recdef' now fails on unfinished automated proofs, use
   176 "(permissive)" option to recover old behavior;
   177 
   178 * HOL: 'inductive' no longer features separate (collective) attributes
   179 for 'intros' (was found too confusing);
   180 
   181 * HOL: properly declared induction rules less_induct and
   182 wf_induct_rule;
   183 
   184 
   185 *** HOL ***
   186 
   187 * HOL: moved over to sane numeral syntax; the new policy is as
   188 follows:
   189 
   190   - 0 and 1 are polymorphic constants, which are defined on any
   191   numeric type (nat, int, real etc.);
   192 
   193   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   194   binary representation internally;
   195 
   196   - type nat has special constructor Suc, and generally prefers Suc 0
   197   over 1::nat and Suc (Suc 0) over 2::nat;
   198 
   199 This change may cause significant problems of INCOMPATIBILITY; here
   200 are some hints on converting existing sources:
   201 
   202   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   203   entities, so expressions involving "-" (unary or binary minus) need
   204   to be spaced properly;
   205 
   206   - existing occurrences of "1" may need to be constraint "1::nat" or
   207   even replaced by Suc 0; similar for old "2";
   208 
   209   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   210 
   211   - remove all special provisions on numerals in proofs;
   212 
   213 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   214 representation (depends on bin_arith_simps in the default context);
   215 
   216 * HOL: symbolic syntax for x^2 (numeral 2);
   217 
   218 * HOL: the class of all HOL types is now called "type" rather than
   219 "term"; INCOMPATIBILITY, need to adapt references to this type class
   220 in axclass/classes, instance/arities, and (usually rare) occurrences
   221 in typings (of consts etc.); internally the class is called
   222 "HOL.type", ML programs should refer to HOLogic.typeS;
   223 
   224 * HOL/record package improvements:
   225   - new derived operations "fields" to build a partial record section,
   226     "extend" to promote a fixed record to a record scheme, and
   227     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   228     declared as simp by default;
   229   - shared operations ("more", "fields", etc.) now need to be always
   230     qualified) --- potential INCOMPATIBILITY;
   231   - removed "make_scheme" operations (use "make" with "extend") --
   232     INCOMPATIBILITY;
   233   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   234   - provides cases/induct rules for use with corresponding Isar
   235     methods (for concrete records, record schemes, concrete more
   236     parts, and schematic more parts -- in that order);
   237   - internal definitions directly based on a light-weight abstract
   238     theory of product types over typedef rather than datatype;
   239 
   240 * HOL: generic code generator for generating executable ML code from
   241 specifications; specific support for HOL constructs such as inductive
   242 datatypes and sets, as well as recursive functions; can be invoked
   243 via 'generate_code' theory section;
   244 
   245 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   246 
   247 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   248 (beware of argument permutation!);
   249 
   250 * HOL: linorder_less_split superseded by linorder_cases;
   251 
   252 * HOL/List: "nodups" renamed to "distinct";
   253 
   254 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   255 to peripheral theory "Hilbert_Choice";
   256 
   257 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   258 in this (rare) case use:
   259 
   260   delSWrapper "split_all_tac"
   261   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   262 
   263 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   264 MAY FAIL;
   265 
   266 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   267 Isabelle's type classes, ^ on functions and relations has too general
   268 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   269 necessary to attach explicit type constraints;
   270 
   271 * HOL/Relation: the prefix name of the infix "O" has been changed from
   272 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   273 renamed accordingly (eg "compI" -> "rel_compI").
   274 
   275 * HOL: syntax translations now work properly with numerals and records
   276 expressions;
   277 
   278 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   279 of "lam" -- INCOMPATIBILITY;
   280 
   281 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   282 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   283 renamed "Product_Type.unit";
   284 
   285 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   286 
   287 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   288 the "cases" method);
   289 
   290 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   291 Florian Kammüller);
   292 
   293 * HOL/IMP: updated and converted to new-style theory format; several
   294 parts turned into readable document, with proper Isar proof texts and
   295 some explanations (by Gerwin Klein);
   296 
   297 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   298 
   299 * HOL-Hyperreal is now a logic image;
   300 
   301 
   302 *** HOLCF ***
   303 
   304 * Isar: consts/constdefs supports mixfix syntax for continuous
   305 operations;
   306 
   307 * Isar: domain package adapted to new-style theory format, e.g. see
   308 HOLCF/ex/Dnat.thy;
   309 
   310 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   311 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   312 lift.induct_tac, always use UU instead of Undef;
   313 
   314 * HOLCF/IMP: updated and converted to new-style theory;
   315 
   316 
   317 *** ZF ***
   318 
   319 * Isar: proper integration of logic-specific tools and packages,
   320 including theory commands '(co)inductive', '(co)datatype',
   321 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   322 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   323 
   324 * theory Main no longer includes AC; for the Axiom of Choice, base
   325 your theory on Main_ZFC;
   326 
   327 * the integer library now covers quotients and remainders, with many
   328 laws relating division to addition, multiplication, etc.;
   329 
   330 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   331 typeless version of the formalism;
   332 
   333 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   334 format;
   335 
   336 * ZF/Induct: new directory for examples of inductive definitions,
   337 including theory Multiset for multiset orderings; converted to
   338 new-style theory format;
   339 
   340 * ZF: many new theorems about lists, ordinals, etc.;
   341 
   342 
   343 *** General ***
   344 
   345 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   346 variable proof controls level of detail: 0 = no proofs (only oracle
   347 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   348 also ref manual for further ML interfaces;
   349 
   350 * Pure/axclass: removed obsolete ML interface
   351 goal_subclass/goal_arity;
   352 
   353 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   354 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   355 separate tokens, so expressions involving minus need to be spaced
   356 properly;
   357 
   358 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   359 rather than "infixl" or "infixr";
   360 
   361 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   362 sort constraint specifications in type inference; e.g. "x::_::foo"
   363 ensures that the type of "x" is of sort "foo" (but not necessarily a
   364 type variable);
   365 
   366 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   367 control output of nested => (types); the default behavior is
   368 "type_brackets";
   369 
   370 * Pure/syntax: builtin parse translation for "_constify" turns valued
   371 tokens into AST constants;
   372 
   373 * Pure/syntax: prefer later declarations of translations and print
   374 translation functions; potential INCOMPATIBILITY: need to reverse
   375 multiple declarations for same syntax element constant;
   376 
   377 * Pure/show_hyps reset by default (in accordance to existing Isar
   378 practice);
   379 
   380 * Provers/classical: renamed addaltern to addafter, addSaltern to
   381 addSafter;
   382 
   383 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   384 as well;
   385 
   386 * system: tested support for MacOS X; should be able to get Isabelle +
   387 Proof General to work in a plain Terminal after installing Poly/ML
   388 (e.g. from the Isabelle distribution area) and GNU bash alone
   389 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   390 support requires further installations, e.g. from
   391 http://fink.sourceforge.net/);
   392 
   393 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   394 
   395 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   396 of 40 MB), cf. ML_OPTIONS;
   397 
   398 * system: Proof General keywords specification is now part of the
   399 Isabelle distribution (see etc/isar-keywords.el);
   400 
   401 * system: support for persistent Proof General sessions (refrain from
   402 outdating all loaded theories on startup); user may create writable
   403 logic images like this: ``isabelle -q HOL Test'';
   404 
   405 * system: smart selection of Isabelle process versus Isabelle
   406 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   407 run both "isabelle" and "Isabelle" even if file names are badly
   408 damaged (executable inspects the case of the first letter of its own
   409 name); added separate "isabelle-process" and "isabelle-interface";
   410 
   411 * system: refrain from any attempt at filtering input streams; no
   412 longer support ``8bit'' encoding of old isabelle font, instead proper
   413 iso-latin characters may now be used; the related isatools
   414 "symbolinput" and "nonascii" have disappeared as well;
   415 
   416 * system: removed old "xterm" interface (the print modes "xterm" and
   417 "xterm_color" are still available for direct use in a suitable
   418 terminal);
   419 
   420 
   421 
   422 New in Isabelle99-2 (February 2001)
   423 -----------------------------------
   424 
   425 *** Overview of INCOMPATIBILITIES ***
   426 
   427 * HOL: please note that theories in the Library and elsewhere often use the
   428 new-style (Isar) format; to refer to their theorems in an ML script you must
   429 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   430 
   431 * HOL: inductive package no longer splits induction rule aggressively,
   432 but only as far as specified by the introductions given; the old
   433 format may be recovered via ML function complete_split_rule or attribute
   434 'split_rule (complete)';
   435 
   436 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   437 gfp_Tarski to gfp_unfold;
   438 
   439 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   440 
   441 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   442 relation); infix "^^" has been renamed "``"; infix "``" has been
   443 renamed "`"; "univalent" has been renamed "single_valued";
   444 
   445 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   446 operation;
   447 
   448 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   449 
   450 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   451 
   452 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   453 consequence, it is no longer monotonic wrt. the local goal context
   454 (which is now passed through the inductive cases);
   455 
   456 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   457 \<gg> to \<ggreater>;
   458 
   459 
   460 *** Document preparation ***
   461 
   462 * \isabellestyle{NAME} selects version of Isabelle output (currently
   463 available: are "it" for near math-mode best-style output, "sl" for
   464 slanted text style, and "tt" for plain type-writer; if no
   465 \isabellestyle command is given, output is according to slanted
   466 type-writer);
   467 
   468 * support sub/super scripts (for single symbols only), input syntax is
   469 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   470 
   471 * some more standard symbols; see Appendix A of the system manual for
   472 the complete list of symbols defined in isabellesym.sty;
   473 
   474 * improved isabelle style files; more abstract symbol implementation
   475 (should now use \isamath{...} and \isatext{...} in custom symbol
   476 definitions);
   477 
   478 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   479 state; Note that presentation of goal states does not conform to
   480 actual human-readable proof documents.  Please do not include goal
   481 states into document output unless you really know what you are doing!
   482 
   483 * proper indentation of antiquoted output with proportional LaTeX
   484 fonts;
   485 
   486 * no_document ML operator temporarily disables LaTeX document
   487 generation;
   488 
   489 * isatool unsymbolize tunes sources for plain ASCII communication;
   490 
   491 
   492 *** Isar ***
   493 
   494 * Pure: Isar now suffers initial goal statements to contain unbound
   495 schematic variables (this does not conform to actual readable proof
   496 documents, due to unpredictable outcome and non-compositional proof
   497 checking); users who know what they are doing may use schematic goals
   498 for Prolog-style synthesis of proven results;
   499 
   500 * Pure: assumption method (an implicit finishing) now handles actual
   501 rules as well;
   502 
   503 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   504 initial goal, declare "that" only as Pure intro (only for single
   505 steps); the "that" rule assumption may now be involved in implicit
   506 finishing, thus ".." becomes a feasible for trivial obtains;
   507 
   508 * Pure: default proof step now includes 'intro_classes'; thus trivial
   509 instance proofs may be performed by "..";
   510 
   511 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   512 statements as well;
   513 
   514 * Pure: more robust selection of calculational rules;
   515 
   516 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   517 rule (as well as the assumption rule);
   518 
   519 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   520 lemmas, using the graph browser tool;
   521 
   522 * Pure: predict failure of "show" in interactive mode;
   523 
   524 * Pure: 'thms_containing' now takes actual terms as arguments;
   525 
   526 * HOL: improved method 'induct' --- now handles non-atomic goals
   527 (potential INCOMPATIBILITY); tuned error handling;
   528 
   529 * HOL: cases and induct rules now provide explicit hints about the
   530 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   531 any remaining facts are inserted into the goal verbatim;
   532 
   533 * HOL: local contexts (aka cases) may now contain term bindings as
   534 well; the 'cases' and 'induct' methods new provide a ?case binding for
   535 the result to be shown in each case;
   536 
   537 * HOL: added 'recdef_tc' command;
   538 
   539 * isatool convert assists in eliminating legacy ML scripts;
   540 
   541 
   542 *** HOL ***
   543 
   544 * HOL/Library: a collection of generic theories to be used together
   545 with main HOL; the theory loader path already includes this directory
   546 by default; the following existing theories have been moved here:
   547 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   548 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   549 
   550 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   551 modelling and verification task performed in Isabelle/HOL +
   552 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   553 
   554 * HOL/Algebra: special summation operator SUM no longer exists, it has
   555 been replaced by setsum; infix 'assoc' now has priority 50 (like
   556 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   557 'domain', this makes the theory consistent with mathematical
   558 literature;
   559 
   560 * HOL basics: added overloaded operations "inverse" and "divide"
   561 (infix "/"), syntax for generic "abs" operation, generic summation
   562 operator \<Sum>;
   563 
   564 * HOL/typedef: simplified package, provide more useful rules (see also
   565 HOL/subset.thy);
   566 
   567 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   568 now expressed as a proper nested rule (old-style tactic scripts may
   569 require atomize_strip_tac to cope with non-atomic premises);
   570 
   571 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   572 to "split_conv" (old name still available for compatibility);
   573 
   574 * HOL: improved concrete syntax for strings (e.g. allows translation
   575 rules with string literals);
   576 
   577 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   578  and Fleuriot's mechanization of analysis, including the transcendental
   579  functions for the reals;
   580 
   581 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   582 
   583 
   584 *** CTT ***
   585 
   586 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   587 "lam" is displayed as TWO lambda-symbols
   588 
   589 * CTT: theory Main now available, containing everything (that is, Bool
   590 and Arith);
   591 
   592 
   593 *** General ***
   594 
   595 * Pure: the Simplifier has been implemented properly as a derived rule
   596 outside of the actual kernel (at last!); the overall performance
   597 penalty in practical applications is about 50%, while reliability of
   598 the Isabelle inference kernel has been greatly improved;
   599 
   600 * print modes "brackets" and "no_brackets" control output of nested =>
   601 (types) and ==> (props); the default behaviour is "brackets";
   602 
   603 * Provers: fast_tac (and friends) now handle actual object-logic rules
   604 as assumptions as well;
   605 
   606 * system: support Poly/ML 4.0;
   607 
   608 * system: isatool install handles KDE version 1 or 2;
   609 
   610 
   611 
   612 New in Isabelle99-1 (October 2000)
   613 ----------------------------------
   614 
   615 *** Overview of INCOMPATIBILITIES ***
   616 
   617 * HOL: simplification of natural numbers is much changed; to partly
   618 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   619 issue the following ML commands:
   620 
   621   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   622   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   623 
   624 * HOL: simplification no longer dives into case-expressions; this is
   625 controlled by "t.weak_case_cong" for each datatype t;
   626 
   627 * HOL: nat_less_induct renamed to less_induct;
   628 
   629 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   630 fixsome to patch .thy and .ML sources automatically;
   631 
   632   select_equality  -> some_equality
   633   select_eq_Ex     -> some_eq_ex
   634   selectI2EX       -> someI2_ex
   635   selectI2         -> someI2
   636   selectI          -> someI
   637   select1_equality -> some1_equality
   638   Eps_sym_eq       -> some_sym_eq_trivial
   639   Eps_eq           -> some_eq_trivial
   640 
   641 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   642 
   643 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   644 instead);
   645 
   646 * HOL: the recursion equations generated by 'recdef' are now called
   647 f.simps instead of f.rules;
   648 
   649 * HOL: qed_spec_mp now also handles bounded ALL as well;
   650 
   651 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   652 sometimes be needed;
   653 
   654 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   655 
   656 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   657 
   658 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   659 product is now "<*>" instead of "Times"; the lexicographic product is
   660 now "<*lex*>" instead of "**";
   661 
   662 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   663 of main HOL, but was unused); better use HOL's datatype package;
   664 
   665 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   666 the old syntax may be recovered as follows:
   667 
   668   syntax (symbols)
   669     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   670       (infixl "\\<oplus>" 100)
   671 
   672 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   673 
   674 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   675 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   676 internally;
   677 
   678 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   679 changed from A/r to A//r;
   680 
   681 * ZF: new treatment of arithmetic (nat & int) may break some old
   682 proofs;
   683 
   684 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   685 rulify -> rule_format, elimify -> elim_format, ...);
   686 
   687 * Isar/Provers: intro/elim/dest attributes changed; renamed
   688 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   689 should have to change intro!! to intro? only); replaced "delrule" by
   690 "rule del";
   691 
   692 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   693 
   694 * Provers: strengthened force_tac by using new first_best_tac;
   695 
   696 * LaTeX document preparation: several changes of isabelle.sty (see
   697 lib/texinputs);
   698 
   699 
   700 *** Document preparation ***
   701 
   702 * formal comments (text blocks etc.) in new-style theories may now
   703 contain antiquotations of thm/prop/term/typ/text to be presented
   704 according to latex print mode; concrete syntax is like this:
   705 @{term[show_types] "f(x) = a + x"};
   706 
   707 * isatool mkdir provides easy setup of Isabelle session directories,
   708 including proper document sources;
   709 
   710 * generated LaTeX sources are now deleted after successful run
   711 (isatool document -c); may retain a copy somewhere else via -D option
   712 of isatool usedir;
   713 
   714 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   715 style files, achieving self-contained LaTeX sources and simplifying
   716 LaTeX debugging;
   717 
   718 * old-style theories now produce (crude) LaTeX output as well;
   719 
   720 * browser info session directories are now self-contained (may be put
   721 on WWW server seperately); improved graphs of nested sessions; removed
   722 graph for 'all sessions';
   723 
   724 * several improvements in isabelle style files; \isabellestyle{it}
   725 produces fake math mode output; \isamarkupheader is now \section by
   726 default; see lib/texinputs/isabelle.sty etc.;
   727 
   728 
   729 *** Isar ***
   730 
   731 * Isar/Pure: local results and corresponding term bindings are now
   732 subject to Hindley-Milner polymorphism (similar to ML); this
   733 accommodates incremental type-inference very nicely;
   734 
   735 * Isar/Pure: new derived language element 'obtain' supports
   736 generalized existence reasoning;
   737 
   738 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   739 support accumulation of results, without applying any rules yet;
   740 useful to collect intermediate results without explicit name
   741 references, and for use with transitivity rules with more than 2
   742 premises;
   743 
   744 * Isar/Pure: scalable support for case-analysis type proofs: new
   745 'case' language element refers to local contexts symbolically, as
   746 produced by certain proof methods; internally, case names are attached
   747 to theorems as "tags";
   748 
   749 * Isar/Pure: theory command 'hide' removes declarations from
   750 class/type/const name spaces;
   751 
   752 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   753 indicate potential overloading;
   754 
   755 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   756 
   757 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   758 "{a,b,c}" instead of {a,b,c};
   759 
   760 * Isar/Pure now provides its own version of intro/elim/dest
   761 attributes; useful for building new logics, but beware of confusion
   762 with the version in Provers/classical;
   763 
   764 * Isar/Pure: the local context of (non-atomic) goals is provided via
   765 case name 'antecedent';
   766 
   767 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   768 to the current context is now done automatically);
   769 
   770 * Isar/Pure: theory command 'method_setup' provides a simple interface
   771 for definining proof methods in ML;
   772 
   773 * Isar/Provers: intro/elim/dest attributes changed; renamed
   774 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   775 most cases, one should have to change intro!! to intro? only);
   776 replaced "delrule" by "rule del";
   777 
   778 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   779 'symmetric' attribute (the latter supercedes [RS sym]);
   780 
   781 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   782 method modifier); 'simp' method: 'only:' modifier removes loopers as
   783 well (including splits);
   784 
   785 * Isar/Provers: Simplifier and Classical methods now support all kind
   786 of modifiers used in the past, including 'cong', 'iff', etc.
   787 
   788 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   789 of Simplifier and Classical reasoner);
   790 
   791 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   792 now support named cases; major packages (inductive, datatype, primrec,
   793 recdef) support case names and properly name parameters;
   794 
   795 * Isar/HOL: new transitivity rules for substitution in inequalities --
   796 monotonicity conditions are extracted to be proven at end of
   797 calculations;
   798 
   799 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   800 method anyway;
   801 
   802 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   803 split_if split_if_asm; datatype package provides theorems foo.splits =
   804 foo.split foo.split_asm for each datatype;
   805 
   806 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   807 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   808 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   809 use "(cases (simplified))" method in proper proof texts);
   810 
   811 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   812 
   813 * Isar: names of theorems etc. may be natural numbers as well;
   814 
   815 * Isar: 'pr' command: optional arguments for goals_limit and
   816 ProofContext.prems_limit; no longer prints theory contexts, but only
   817 proof states;
   818 
   819 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   820 additional print modes to be specified; e.g. "pr(latex)" will print
   821 proof state according to the Isabelle LaTeX style;
   822 
   823 * Isar: improved support for emulating tactic scripts, including proof
   824 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   825 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   826 (for HOL datatypes);
   827 
   828 * Isar: simplified (more robust) goal selection of proof methods: 1st
   829 goal, all goals, or explicit goal specifier (tactic emulation); thus
   830 'proof method scripts' have to be in depth-first order;
   831 
   832 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   833 
   834 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   835 should instead use individual commands for printing items
   836 (print_commands, print_methods etc.);
   837 
   838 * Isar: added 'nothing' --- the empty list of theorems;
   839 
   840 
   841 *** HOL ***
   842 
   843 * HOL/MicroJava: formalization of a fragment of Java, together with a
   844 corresponding virtual machine and a specification of its bytecode
   845 verifier and a lightweight bytecode verifier, including proofs of
   846 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   847 Cornelia Pusch (see also the homepage of project Bali at
   848 http://isabelle.in.tum.de/Bali/);
   849 
   850 * HOL/Algebra: new theory of rings and univariate polynomials, by
   851 Clemens Ballarin;
   852 
   853 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   854 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   855 Rasmussen;
   856 
   857 * HOL/Lattice: fundamental concepts of lattice theory and order
   858 structures, including duals, properties of bounds versus algebraic
   859 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   860 Theorem for complete lattices etc.; may also serve as a demonstration
   861 for abstract algebraic reasoning using axiomatic type classes, and
   862 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   863 
   864 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   865 von Oheimb;
   866 
   867 * HOL/IMPP: extension of IMP with local variables and mutually
   868 recursive procedures, by David von Oheimb;
   869 
   870 * HOL/Lambda: converted into new-style theory and document;
   871 
   872 * HOL/ex/Multiquote: example of multiple nested quotations and
   873 anti-quotations -- basically a generalized version of de-Bruijn
   874 representation; very useful in avoiding lifting of operations;
   875 
   876 * HOL/record: added general record equality rule to simpset; fixed
   877 select-update simplification procedure to handle extended records as
   878 well; admit "r" as field name;
   879 
   880 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   881 other numeric types and also as the identity of groups, rings, etc.;
   882 
   883 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   884 Types nat and int belong to this axclass;
   885 
   886 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   887    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   888    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   889   two terms #m*u and #n*u are replaced by #(m+n)*u
   890     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   891   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   892     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   893 
   894 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   895 powerful prover for predicate logic but knows nothing of clasets; see
   896 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   897 
   898 * HOL: new version of "case_tac" subsumes both boolean case split and
   899 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   900 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   901 
   902 * HOL: simplification no longer dives into case-expressions: only the
   903 selector expression is simplified, but not the remaining arms; to
   904 enable full simplification of case-expressions for datatype t, you may
   905 remove t.weak_case_cong from the simpset, either globally (Delcongs
   906 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   907 
   908 * HOL/recdef: the recursion equations generated by 'recdef' for
   909 function 'f' are now called f.simps instead of f.rules; if all
   910 termination conditions are proved automatically, these simplification
   911 rules are added to the simpset, as in primrec; rules may be named
   912 individually as well, resulting in a separate list of theorems for
   913 each equation;
   914 
   915 * HOL/While is a new theory that provides a while-combinator. It
   916 permits the definition of tail-recursive functions without the
   917 provision of a termination measure. The latter is necessary once the
   918 invariant proof rule for while is applied.
   919 
   920 * HOL: new (overloaded) notation for the set of elements below/above
   921 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   922 
   923 * HOL: theorems impI, allI, ballI bound as "strip";
   924 
   925 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   926 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   927 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   928 
   929 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   930 
   931 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   932 main HOL, but was unused);
   933 
   934 * HOL: fewer consts declared as global (e.g. have to refer to
   935 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   936 
   937 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   938 in case of overlap with user translations (e.g. judgements over
   939 tuples); (note that the underlying logical represenation is still
   940 bogus);
   941 
   942 
   943 *** ZF ***
   944 
   945 * ZF: simplification automatically cancels common terms in arithmetic
   946 expressions over nat and int;
   947 
   948 * ZF: new treatment of nat to minimize type-checking: all operators
   949 coerce their operands to a natural number using the function natify,
   950 making the algebraic laws unconditional;
   951 
   952 * ZF: as above, for int: operators coerce their operands to an integer
   953 using the function intify;
   954 
   955 * ZF: the integer library now contains many of the usual laws for the
   956 orderings, including $<=, and monotonicity laws for $+ and $*;
   957 
   958 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   959 simplification;
   960 
   961 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   962 to the simplifier and classical reasoner simultaneously;
   963 
   964 
   965 *** General ***
   966 
   967 * Provers: blast_tac now handles actual object-logic rules as
   968 assumptions; note that auto_tac uses blast_tac internally as well;
   969 
   970 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   971 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   972 
   973 * Provers: delrules now handles destruct rules as well (no longer need
   974 explicit make_elim);
   975 
   976 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   977   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   978 use instead the strong form,
   979   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   980 in HOL, FOL and ZF the function cla_make_elim will create such rules
   981 from destruct-rules;
   982 
   983 * Provers: Simplifier.easy_setup provides a fast path to basic
   984 Simplifier setup for new object-logics;
   985 
   986 * Pure: AST translation rules no longer require constant head on LHS;
   987 
   988 * Pure: improved name spaces: ambiguous output is qualified; support
   989 for hiding of names;
   990 
   991 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   992 XSYMBOL_HOME; no longer need to do manual configuration in most
   993 situations;
   994 
   995 * system: compression of ML heaps images may now be controlled via -c
   996 option of isabelle and isatool usedir (currently only observed by
   997 Poly/ML);
   998 
   999 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1000 useful for remote X11);
  1001 
  1002 * system: provide TAGS file for Isabelle sources;
  1003 
  1004 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1005 order;
  1006 
  1007 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1008 timing flag supersedes proof_timing and Toplevel.trace;
  1009 
  1010 * ML: new combinators |>> and |>>> for incremental transformations
  1011 with secondary results (e.g. certain theory extensions):
  1012 
  1013 * ML: PureThy.add_defs gets additional argument to indicate potential
  1014 overloading (usually false);
  1015 
  1016 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1017 results;
  1018 
  1019 
  1020 
  1021 New in Isabelle99 (October 1999)
  1022 --------------------------------
  1023 
  1024 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1025 
  1026 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1027 are no longer simplified.  (This allows the simplifier to unfold recursive
  1028 functional programs.)  To restore the old behaviour, declare
  1029 
  1030     Delcongs [if_weak_cong];
  1031 
  1032 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1033 complement;
  1034 
  1035 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1036 
  1037 * HOL/datatype: mutual_induct_tac no longer exists --
  1038   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1039 
  1040 * HOL/typedef: fixed type inference for representing set; type
  1041 arguments now have to occur explicitly on the rhs as type constraints;
  1042 
  1043 * ZF: The con_defs part of an inductive definition may no longer refer
  1044 to constants declared in the same theory;
  1045 
  1046 * HOL, ZF: the function mk_cases, generated by the inductive
  1047 definition package, has lost an argument.  To simplify its result, it
  1048 uses the default simpset instead of a supplied list of theorems.
  1049 
  1050 * HOL/List: the constructors of type list are now Nil and Cons;
  1051 
  1052 * Simplifier: the type of the infix ML functions
  1053         setSSolver addSSolver setSolver addSolver
  1054 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1055 for packaging solvers. A solver is created via
  1056         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1057 where the string argument is only a comment.
  1058 
  1059 
  1060 *** Proof tools ***
  1061 
  1062 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1063 decision procedure for linear arithmetic. Currently it is used for
  1064 types `nat', `int', and `real' in HOL (see below); it can, should and
  1065 will be instantiated for other types and logics as well.
  1066 
  1067 * The simplifier now accepts rewrite rules with flexible heads, eg
  1068      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1069   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1070   matching.
  1071 
  1072 
  1073 *** General ***
  1074 
  1075 * New Isabelle/Isar subsystem provides an alternative to traditional
  1076 tactical theorem proving; together with the ProofGeneral/isar user
  1077 interface it offers an interactive environment for developing human
  1078 readable proof documents (Isar == Intelligible semi-automated
  1079 reasoning); for further information see isatool doc isar-ref,
  1080 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1081 
  1082 * improved and simplified presentation of theories: better HTML markup
  1083 (including colors), graph views in several sizes; isatool usedir now
  1084 provides a proper interface for user theories (via -P option); actual
  1085 document preparation based on (PDF)LaTeX is available as well (for
  1086 new-style theories only); see isatool doc system for more information;
  1087 
  1088 * native support for Proof General, both for classic Isabelle and
  1089 Isabelle/Isar;
  1090 
  1091 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1092 using the graph browser tool;
  1093 
  1094 * Isabelle manuals now also available as PDF;
  1095 
  1096 * theory loader rewritten from scratch (may not be fully
  1097 bug-compatible); old loadpath variable has been replaced by show_path,
  1098 add_path, del_path, reset_path functions; new operations such as
  1099 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1100 isatool doc ref);
  1101 
  1102 * improved isatool install: option -k creates KDE application icon,
  1103 option -p DIR installs standalone binaries;
  1104 
  1105 * added ML_PLATFORM setting (useful for cross-platform installations);
  1106 more robust handling of platform specific ML images for SML/NJ;
  1107 
  1108 * the settings environment is now statically scoped, i.e. it is never
  1109 created again in sub-processes invoked from isabelle, isatool, or
  1110 Isabelle;
  1111 
  1112 * path element specification '~~' refers to '$ISABELLE_HOME';
  1113 
  1114 * in locales, the "assumes" and "defines" parts may be omitted if
  1115 empty;
  1116 
  1117 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1118 long arrows);
  1119 
  1120 * new print_mode "HTML";
  1121 
  1122 * new flag show_tags controls display of tags of theorems (which are
  1123 basically just comments that may be attached by some tools);
  1124 
  1125 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1126 mode and goal output format:
  1127 
  1128 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1129 244c244
  1130 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1131 ---
  1132 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1133 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1134 181c181
  1135 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1136 ---
  1137 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1138 
  1139 * function bind_thms stores lists of theorems (cf. bind_thm);
  1140 
  1141 * new shorthand tactics ftac, eatac, datac, fatac;
  1142 
  1143 * qed (and friends) now accept "" as result name; in that case the
  1144 theorem is not stored, but proper checks and presentation of the
  1145 result still apply;
  1146 
  1147 * theorem database now also indexes constants "Trueprop", "all",
  1148 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1149 
  1150 
  1151 *** HOL ***
  1152 
  1153 ** HOL arithmetic **
  1154 
  1155 * There are now decision procedures for linear arithmetic over nat and
  1156 int:
  1157 
  1158 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1159 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1160 are treated as atomic; subformulae not involving type `nat' or `int'
  1161 are ignored; quantified subformulae are ignored unless they are
  1162 positive universal or negative existential. The tactic has to be
  1163 invoked by hand and can be a little bit slow. In particular, the
  1164 running time is exponential in the number of occurrences of `min' and
  1165 `max', and `-' on `nat'.
  1166 
  1167 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1168 (negated) (in)equalities among the premises and the conclusion into
  1169 account (i.e. no compound formulae) and does not know about `min' and
  1170 `max', and `-' on `nat'. It is fast and is used automatically by the
  1171 simplifier.
  1172 
  1173 NB: At the moment, these decision procedures do not cope with mixed
  1174 nat/int formulae where the two parts interact, such as `m < n ==>
  1175 int(m) < int(n)'.
  1176 
  1177 * HOL/Numeral provides a generic theory of numerals (encoded
  1178 efficiently as bit strings); setup for types nat/int/real is in place;
  1179 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1180 int, existing theories and proof scripts may require a few additional
  1181 type constraints;
  1182 
  1183 * integer division and remainder can now be performed on constant
  1184 arguments;
  1185 
  1186 * many properties of integer multiplication, division and remainder
  1187 are now available;
  1188 
  1189 * An interface to the Stanford Validity Checker (SVC) is available through the
  1190 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1191 are proved automatically.  SVC must be installed separately, and its results
  1192 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1193 invocation of the underlying oracle).  For SVC see
  1194   http://verify.stanford.edu/SVC
  1195 
  1196 * IsaMakefile: the HOL-Real target now builds an actual image;
  1197 
  1198 
  1199 ** HOL misc **
  1200 
  1201 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1202 (in Isabelle/Isar) -- by Gertrud Bauer;
  1203 
  1204 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1205 analysis for assembly languages with subtypes;
  1206 
  1207 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1208 -- avoids syntactic ambiguities and treats state, transition, and
  1209 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1210 changed syntax and (many) tactics;
  1211 
  1212 * HOL/inductive: Now also handles more general introduction rules such
  1213   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1214   theorems are now maintained within the theory (maintained via the
  1215   "mono" attribute);
  1216 
  1217 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1218   (using function types) such as
  1219 
  1220   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1221 
  1222 * HOL/record: record_simproc (part of the default simpset) takes care
  1223 of selectors applied to updated records; record_split_tac is no longer
  1224 part of the default claset; update_defs may now be removed from the
  1225 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1226 
  1227   claset_ref () := claset() addSWrapper record_split_wrapper;
  1228   Delsimprocs [record_simproc]
  1229 
  1230 * HOL/typedef: fixed type inference for representing set; type
  1231 arguments now have to occur explicitly on the rhs as type constraints;
  1232 
  1233 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1234 names rather than an ML expression;
  1235 
  1236 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1237 supplied later.  Program schemes can be defined, such as
  1238     "While B C s = (if B s then While B C (C s) else s)"
  1239 where the well-founded relation can be chosen after B and C have been given.
  1240 
  1241 * HOL/List: the constructors of type list are now Nil and Cons;
  1242 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1243 course, ML tools referring to List.list.op # etc. have to be adapted;
  1244 
  1245 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1246 disabled by default; run isabelle with option -m HOL to get back to
  1247 the original Gordon/HOL-style output;
  1248 
  1249 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1250 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1251 
  1252 * HOL basic syntax simplified (more orthogonal): all variants of
  1253 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1254 Eps operator is provided as well: "SOME x. P[x]";
  1255 
  1256 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1257 
  1258 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1259 thus available for user theories;
  1260 
  1261 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1262 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1263 time;
  1264 
  1265 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1266 several times and then mp;
  1267 
  1268 
  1269 *** LK ***
  1270 
  1271 * the notation <<...>> is now available as a notation for sequences of
  1272 formulas;
  1273 
  1274 * the simplifier is now installed
  1275 
  1276 * the axiom system has been generalized (thanks to Soren Heilmann)
  1277 
  1278 * the classical reasoner now has a default rule database
  1279 
  1280 
  1281 *** ZF ***
  1282 
  1283 * new primrec section allows primitive recursive functions to be given
  1284 directly (as in HOL) over datatypes and the natural numbers;
  1285 
  1286 * new tactics induct_tac and exhaust_tac for induction (or case
  1287 analysis) over datatypes and the natural numbers;
  1288 
  1289 * the datatype declaration of type T now defines the recursor T_rec;
  1290 
  1291 * simplification automatically does freeness reasoning for datatype
  1292 constructors;
  1293 
  1294 * automatic type-inference, with AddTCs command to insert new
  1295 type-checking rules;
  1296 
  1297 * datatype introduction rules are now added as Safe Introduction rules
  1298 to the claset;
  1299 
  1300 * the syntax "if P then x else y" is now available in addition to
  1301 if(P,x,y);
  1302 
  1303 
  1304 *** Internal programming interfaces ***
  1305 
  1306 * tuned simplifier trace output; new flag debug_simp;
  1307 
  1308 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1309 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1310 
  1311 * AxClass.axclass_tac lost the theory argument;
  1312 
  1313 * tuned current_goals_markers semantics: begin / end goal avoids
  1314 printing empty lines;
  1315 
  1316 * removed prs and prs_fn hook, which was broken because it did not
  1317 include \n in its semantics, forcing writeln to add one
  1318 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1319 string -> unit if you really want to output text without newline;
  1320 
  1321 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1322 plain output, interface builders may have to enable 'isabelle_font'
  1323 mode to get Isabelle font glyphs as before;
  1324 
  1325 * refined token_translation interface; INCOMPATIBILITY: output length
  1326 now of type real instead of int;
  1327 
  1328 * theory loader actions may be traced via new ThyInfo.add_hook
  1329 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1330 your own database of information attached to *whole* theories -- as
  1331 opposed to intra-theory data slots offered via TheoryDataFun;
  1332 
  1333 * proper handling of dangling sort hypotheses (at last!);
  1334 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1335 extra sort hypotheses that can be witnessed from the type signature;
  1336 the force_strip_shyps flag is gone, any remaining shyps are simply
  1337 left in the theorem (with a warning issued by strip_shyps_warning);
  1338 
  1339 
  1340 
  1341 New in Isabelle98-1 (October 1998)
  1342 ----------------------------------
  1343 
  1344 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1345 
  1346 * several changes of automated proof tools;
  1347 
  1348 * HOL: major changes to the inductive and datatype packages, including
  1349 some minor incompatibilities of theory syntax;
  1350 
  1351 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1352 called `inj_on';
  1353 
  1354 * HOL: removed duplicate thms in Arith:
  1355   less_imp_add_less  should be replaced by  trans_less_add1
  1356   le_imp_add_le      should be replaced by  trans_le_add1
  1357 
  1358 * HOL: unary minus is now overloaded (new type constraints may be
  1359 required);
  1360 
  1361 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1362 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1363 now taken as an integer constant.
  1364 
  1365 * Pure: ML function 'theory_of' renamed to 'theory';
  1366 
  1367 
  1368 *** Proof tools ***
  1369 
  1370 * Simplifier:
  1371   1. Asm_full_simp_tac is now more aggressive.
  1372      1. It will sometimes reorient premises if that increases their power to
  1373         simplify.
  1374      2. It does no longer proceed strictly from left to right but may also
  1375         rotate premises to achieve further simplification.
  1376      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1377      old Asm_full_simp_tac in that it does not rotate premises.
  1378   2. The simplifier now knows a little bit about nat-arithmetic.
  1379 
  1380 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1381 allows for selected deletion of wrappers, by introduction of names for
  1382 wrapper functionals.  This implies that addbefore, addSbefore,
  1383 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1384 and that adding two tactics with the same name overwrites the first
  1385 one (emitting a warning).
  1386   type wrapper = (int -> tactic) -> (int -> tactic)
  1387   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1388   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1389   delWrapper, delSWrapper: claset *  string            -> claset
  1390   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1391 
  1392 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1393 semantics; addbefore now affects only the unsafe part of step_tac
  1394 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1395 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1396 by Force_tac;
  1397 
  1398 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1399 compWrapper; added safe wrapper (and access functions for it);
  1400 
  1401 * HOL/split_all_tac is now much faster and fails if there is nothing
  1402 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1403 and the names of the automatically generated variables have changed.
  1404 split_all_tac has moved within claset() from unsafe wrappers to safe
  1405 wrappers, which means that !!-bound variables are split much more
  1406 aggressively, and safe_tac and clarify_tac now split such variables.
  1407 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1408 Note: the same holds for record_split_tac, which does the job of
  1409 split_all_tac for record fields.
  1410 
  1411 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1412 permanently to the default simpset using Addsplits just like
  1413 Addsimps. They can be removed via Delsplits just like
  1414 Delsimps. Lower-case versions are also available.
  1415 
  1416 * HOL/Simplifier: The rule split_if is now part of the default
  1417 simpset. This means that the simplifier will eliminate all occurrences
  1418 of if-then-else in the conclusion of a goal. To prevent this, you can
  1419 either remove split_if completely from the default simpset by
  1420 `Delsplits [split_if]' or remove it in a specific call of the
  1421 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1422 other case splitting rules to/from the default simpset: every datatype
  1423 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1424 t is the name of the datatype).
  1425 
  1426 * Classical reasoner / Simplifier combination: new force_tac (and
  1427 derivatives Force_tac, force) combines rewriting and classical
  1428 reasoning (and whatever other tools) similarly to auto_tac, but is
  1429 aimed to solve the given subgoal completely.
  1430 
  1431 
  1432 *** General ***
  1433 
  1434 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1435 and `goalw': the theory is no longer needed as an explicit argument -
  1436 the current theory context is used; assumptions are no longer returned
  1437 at the ML-level unless one of them starts with ==> or !!; it is
  1438 recommended to convert to these new commands using isatool fixgoal
  1439 (backup your sources first!);
  1440 
  1441 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1442 the current theory context, and 'theory' to lookup stored theories;
  1443 
  1444 * new theory section 'locale' for declaring constants, assumptions and
  1445 definitions that have local scope;
  1446 
  1447 * new theory section 'nonterminals' for purely syntactic types;
  1448 
  1449 * new theory section 'setup' for generic ML setup functions
  1450 (e.g. package initialization);
  1451 
  1452 * the distribution now includes Isabelle icons: see
  1453 lib/logo/isabelle-{small,tiny}.xpm;
  1454 
  1455 * isatool install - install binaries with absolute references to
  1456 ISABELLE_HOME/bin;
  1457 
  1458 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1459 
  1460 * print mode 'emacs' reserved for Isamode;
  1461 
  1462 * support multiple print (ast) translations per constant name;
  1463 
  1464 * theorems involving oracles are now printed with a suffixed [!];
  1465 
  1466 
  1467 *** HOL ***
  1468 
  1469 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1470 
  1471 * HOL/inductive package reorganized and improved: now supports mutual
  1472 definitions such as
  1473 
  1474   inductive EVEN ODD
  1475     intrs
  1476       null "0 : EVEN"
  1477       oddI "n : EVEN ==> Suc n : ODD"
  1478       evenI "n : ODD ==> Suc n : EVEN"
  1479 
  1480 new theorem list "elims" contains an elimination rule for each of the
  1481 recursive sets; inductive definitions now handle disjunctive premises
  1482 correctly (also ZF);
  1483 
  1484 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1485 "mutual_induct" no longer exists - the induction rule is always
  1486 contained in "induct";
  1487 
  1488 
  1489 * HOL/datatype package re-implemented and greatly improved: now
  1490 supports mutually recursive datatypes such as
  1491 
  1492   datatype
  1493     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1494             | SUM ('a aexp) ('a aexp)
  1495             | DIFF ('a aexp) ('a aexp)
  1496             | NUM 'a
  1497   and
  1498     'a bexp = LESS ('a aexp) ('a aexp)
  1499             | AND ('a bexp) ('a bexp)
  1500             | OR ('a bexp) ('a bexp)
  1501 
  1502 as well as indirectly recursive datatypes such as
  1503 
  1504   datatype
  1505     ('a, 'b) term = Var 'a
  1506                   | App 'b ((('a, 'b) term) list)
  1507 
  1508 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1509 induction on mutually / indirectly recursive datatypes.
  1510 
  1511 Primrec equations are now stored in theory and can be accessed via
  1512 <function_name>.simps.
  1513 
  1514 INCOMPATIBILITIES:
  1515 
  1516   - Theories using datatypes must now have theory Datatype as an
  1517     ancestor.
  1518   - The specific <typename>.induct_tac no longer exists - use the
  1519     generic induct_tac instead.
  1520   - natE has been renamed to nat.exhaust - use exhaust_tac
  1521     instead of res_inst_tac ... natE. Note that the variable
  1522     names in nat.exhaust differ from the names in natE, this
  1523     may cause some "fragile" proofs to fail.
  1524   - The theorems split_<typename>_case and split_<typename>_case_asm
  1525     have been renamed to <typename>.split and <typename>.split_asm.
  1526   - Since default sorts of type variables are now handled correctly,
  1527     some datatype definitions may have to be annotated with explicit
  1528     sort constraints.
  1529   - Primrec definitions no longer require function name and type
  1530     of recursive argument.
  1531 
  1532 Consider using isatool fixdatatype to adapt your theories and proof
  1533 scripts to the new package (backup your sources first!).
  1534 
  1535 
  1536 * HOL/record package: considerably improved implementation; now
  1537 includes concrete syntax for record types, terms, updates; theorems
  1538 for surjective pairing and splitting !!-bound record variables; proof
  1539 support is as follows:
  1540 
  1541   1) standard conversions (selectors or updates applied to record
  1542 constructor terms) are part of the standard simpset;
  1543 
  1544   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1545 made part of standard simpset and claset via addIffs;
  1546 
  1547   3) a tactic for record field splitting (record_split_tac) is part of
  1548 the standard claset (addSWrapper);
  1549 
  1550 To get a better idea about these rules you may retrieve them via
  1551 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1552 the name of your record type.
  1553 
  1554 The split tactic 3) conceptually simplifies by the following rule:
  1555 
  1556   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1557 
  1558 Thus any record variable that is bound by meta-all will automatically
  1559 blow up into some record constructor term, consequently the
  1560 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1561 solve record problems automatically.
  1562 
  1563 
  1564 * reorganized the main HOL image: HOL/Integ and String loaded by
  1565 default; theory Main includes everything;
  1566 
  1567 * automatic simplification of integer sums and comparisons, using cancellation;
  1568 
  1569 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1570 
  1571 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1572 
  1573 * many new identities for unions, intersections, set difference, etc.;
  1574 
  1575 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1576 called split_if, split_split, split_sum_case and split_nat_case (to go
  1577 with add/delsplits);
  1578 
  1579 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1580 (?x::unit) = (); this is made part of the default simpset, which COULD
  1581 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1582 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1583 unit_abs_eta_conv is added in order to counter the effect of
  1584 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1585 %u.f();
  1586 
  1587 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1588 makes more sense);
  1589 
  1590 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1591   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1592   disjointness reasoning but breaking a few old proofs.
  1593 
  1594 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1595 to 'converse' from 'inverse' (for compatibility with ZF and some
  1596 literature);
  1597 
  1598 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1599 the well-founded relation;
  1600 
  1601 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1602     Compl A.  The "Compl" syntax remains available as input syntax for this
  1603     release ONLY.
  1604 
  1605 * HOL/Update: new theory of function updates:
  1606     f(a:=b) == %x. if x=a then b else f x
  1607 may also be iterated as in f(a:=b,c:=d,...);
  1608 
  1609 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1610 
  1611 * HOL/List:
  1612   - new function list_update written xs[i:=v] that updates the i-th
  1613     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1614   - new function `upt' written [i..j(] which generates the list
  1615     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1616     bound write [i..j], which is a shorthand for [i..j+1(].
  1617   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1618 
  1619 * HOL/Arith:
  1620   - removed 'pred' (predecessor) function;
  1621   - generalized some theorems about n-1;
  1622   - many new laws about "div" and "mod";
  1623   - new laws about greatest common divisors (see theory ex/Primes);
  1624 
  1625 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1626 instead of "inverse";
  1627 
  1628 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1629   of the multiset ordering;
  1630 
  1631 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1632   (not included by default);
  1633 
  1634 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1635 
  1636 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1637   programs, i.e. different program variables may have different types.
  1638 
  1639 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1640   [previously, this check worked only if the rewrite rule was unconditional]
  1641   Now rew can involve either definitions or equalities (either == or =).
  1642 
  1643 
  1644 *** ZF ***
  1645 
  1646 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1647   only the theorems proved on ZF.ML;
  1648 
  1649 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1650   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1651   disjointness reasoning but breaking a few old proofs.
  1652 
  1653 * ZF/Update: new theory of function updates
  1654     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1655   may also be iterated as in f(a:=b,c:=d,...);
  1656 
  1657 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1658 
  1659 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1660   [previously, this check worked only if the rewrite rule was unconditional]
  1661   Now rew can involve either definitions or equalities (either == or =).
  1662 
  1663 * case_tac provided for compatibility with HOL
  1664     (like the old excluded_middle_tac, but with subgoals swapped)
  1665 
  1666 
  1667 *** Internal programming interfaces ***
  1668 
  1669 * Pure: several new basic modules made available for general use, see
  1670 also src/Pure/README;
  1671 
  1672 * improved the theory data mechanism to support encapsulation (data
  1673 kind name replaced by private Object.kind, acting as authorization
  1674 key); new type-safe user interface via functor TheoryDataFun; generic
  1675 print_data function becomes basically useless;
  1676 
  1677 * removed global_names compatibility flag -- all theory declarations
  1678 are qualified by default;
  1679 
  1680 * module Pure/Syntax now offers quote / antiquote translation
  1681 functions (useful for Hoare logic etc. with implicit dependencies);
  1682 see HOL/ex/Antiquote for an example use;
  1683 
  1684 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1685 cterm -> thm;
  1686 
  1687 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1688 subgoal;
  1689 
  1690 * Display.print_goals function moved to Locale.print_goals;
  1691 
  1692 * standard print function for goals supports current_goals_markers
  1693 variable for marking begin of proof, end of proof, start of goal; the
  1694 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1695 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1696 for example;
  1697 
  1698 
  1699 
  1700 New in Isabelle98 (January 1998)
  1701 --------------------------------
  1702 
  1703 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1704 
  1705 * changed lexical syntax of terms / types: dots made part of long
  1706 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1707 
  1708 * simpset (and claset) reference variable replaced by functions
  1709 simpset / simpset_ref;
  1710 
  1711 * no longer supports theory aliases (via merge) and non-trivial
  1712 implicit merge of thms' signatures;
  1713 
  1714 * most internal names of constants changed due to qualified names;
  1715 
  1716 * changed Pure/Sequence interface (see Pure/seq.ML);
  1717 
  1718 
  1719 *** General Changes ***
  1720 
  1721 * hierachically structured name spaces (for consts, types, axms, thms
  1722 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1723 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1724 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1725 long_names for fully qualified output names; NOTE: ML programs
  1726 (special tactics, packages etc.) referring to internal names may have
  1727 to be adapted to cope with fully qualified names; in case of severe
  1728 backward campatibility problems try setting 'global_names' at compile
  1729 time to have enrything declared within a flat name space; one may also
  1730 fine tune name declarations in theories via the 'global' and 'local'
  1731 section;
  1732 
  1733 * reimplemented the implicit simpset and claset using the new anytype
  1734 data filed in signatures; references simpset:simpset ref etc. are
  1735 replaced by functions simpset:unit->simpset and
  1736 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1737 to patch your ML files accordingly;
  1738 
  1739 * HTML output now includes theory graph data for display with Java
  1740 applet or isatool browser; data generated automatically via isatool
  1741 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1742 
  1743 * defs may now be conditional; improved rewrite_goals_tac to handle
  1744 conditional equations;
  1745 
  1746 * defs now admits additional type arguments, using TYPE('a) syntax;
  1747 
  1748 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1749 creates a new theory node; implicit merge of thms' signatures is
  1750 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1751 transfer:theory->thm->thm in (rare) cases;
  1752 
  1753 * improved handling of draft signatures / theories; draft thms (and
  1754 ctyps, cterms) are automatically promoted to real ones;
  1755 
  1756 * slightly changed interfaces for oracles: admit many per theory, named
  1757 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1758 
  1759 * print_goals: optional output of const types (set show_consts and
  1760 show_types);
  1761 
  1762 * improved output of warnings (###) and errors (***);
  1763 
  1764 * subgoal_tac displays a warning if the new subgoal has type variables;
  1765 
  1766 * removed old README and Makefiles;
  1767 
  1768 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1769 
  1770 * removed obsolete init_pps and init_database;
  1771 
  1772 * deleted the obsolete tactical STATE, which was declared by
  1773     fun STATE tacfun st = tacfun st st;
  1774 
  1775 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1776 (which abbreviates $HOME);
  1777 
  1778 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1779 use isatool fixseq to adapt your ML programs (this works for fully
  1780 qualified references to the Sequence structure only!);
  1781 
  1782 * use_thy no longer requires writable current directory; it always
  1783 reloads .ML *and* .thy file, if either one is out of date;
  1784 
  1785 
  1786 *** Classical Reasoner ***
  1787 
  1788 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1789 tactics that use classical reasoning to simplify a subgoal without
  1790 splitting it into several subgoals;
  1791 
  1792 * Safe_tac: like safe_tac but uses the default claset;
  1793 
  1794 
  1795 *** Simplifier ***
  1796 
  1797 * added simplification meta rules:
  1798     (asm_)(full_)simplify: simpset -> thm -> thm;
  1799 
  1800 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1801 logics (again);
  1802 
  1803 * added prems argument to simplification procedures;
  1804 
  1805 * HOL, FOL, ZF: added infix function `addsplits':
  1806   instead of `<simpset> setloop (split_tac <thms>)'
  1807   you can simply write `<simpset> addsplits <thms>'
  1808 
  1809 
  1810 *** Syntax ***
  1811 
  1812 * TYPE('a) syntax for type reflection terms;
  1813 
  1814 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1815 
  1816 * pretty printer: changed order of mixfix annotation preference (again!);
  1817 
  1818 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1819 
  1820 
  1821 *** HOL ***
  1822 
  1823 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1824   with `addloop' of the simplifier to faciliate case splitting in premises.
  1825 
  1826 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1827 
  1828 * HOL/Auth: new protocol proofs including some for the Internet
  1829   protocol TLS;
  1830 
  1831 * HOL/Map: new theory of `maps' a la VDM;
  1832 
  1833 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1834 cancelling out common nat summands from =, <, <= (in)equalities, or
  1835 differences; simplification procedures nat_cancel_factor for
  1836 cancelling common factor from =, <, <= (in)equalities over natural
  1837 sums; nat_cancel contains both kinds of procedures, it is installed by
  1838 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1839 
  1840 * HOL/simplifier: terms of the form
  1841   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1842   are rewritten to
  1843   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1844   and those of the form
  1845   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1846   are rewritten to
  1847   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1848 
  1849 * HOL/datatype
  1850   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1851 
  1852   P(t_case f1 ... fn x) =
  1853      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1854         ...
  1855        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1856      )
  1857 
  1858   and a theorem `split_t_case_asm' of the form
  1859 
  1860   P(t_case f1 ... fn x) =
  1861     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1862         ...
  1863        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1864      )
  1865   which can be added to a simpset via `addsplits'. The existing theorems
  1866   expand_list_case and expand_option_case have been renamed to
  1867   split_list_case and split_option_case.
  1868 
  1869 * HOL/Arithmetic:
  1870   - `pred n' is automatically converted to `n-1'.
  1871     Users are strongly encouraged not to use `pred' any longer,
  1872     because it will disappear altogether at some point.
  1873   - Users are strongly encouraged to write "0 < n" rather than
  1874     "n ~= 0". Theorems and proof tools have been modified towards this
  1875     `standard'.
  1876 
  1877 * HOL/Lists:
  1878   the function "set_of_list" has been renamed "set" (and its theorems too);
  1879   the function "nth" now takes its arguments in the reverse order and
  1880   has acquired the infix notation "!" as in "xs!n".
  1881 
  1882 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1883 
  1884 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1885   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1886 
  1887 * HOL/record: extensible records with schematic structural subtyping
  1888 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1889 still lacks various theorems and concrete record syntax;
  1890 
  1891 
  1892 *** HOLCF ***
  1893 
  1894 * removed "axioms" and "generated by" sections;
  1895 
  1896 * replaced "ops" section by extended "consts" section, which is capable of
  1897   handling the continuous function space "->" directly;
  1898 
  1899 * domain package:
  1900   . proves theorems immediately and stores them in the theory,
  1901   . creates hierachical name space,
  1902   . now uses normal mixfix annotations (instead of cinfix...),
  1903   . minor changes to some names and values (for consistency),
  1904   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1905   . separator between mutual domain defs: changed "," to "and",
  1906   . improved handling of sort constraints;  now they have to
  1907     appear on the left-hand side of the equations only;
  1908 
  1909 * fixed LAM <x,y,zs>.b syntax;
  1910 
  1911 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1912 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1913 
  1914 
  1915 *** FOL and ZF ***
  1916 
  1917 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1918   with `addloop' of the simplifier to faciliate case splitting in premises.
  1919 
  1920 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1921 in HOL, they strip ALL and --> from proved theorems;
  1922 
  1923 
  1924 
  1925 New in Isabelle94-8 (May 1997)
  1926 ------------------------------
  1927 
  1928 *** General Changes ***
  1929 
  1930 * new utilities to build / run / maintain Isabelle etc. (in parts
  1931 still somewhat experimental); old Makefiles etc. still functional;
  1932 
  1933 * new 'Isabelle System Manual';
  1934 
  1935 * INSTALL text, together with ./configure and ./build scripts;
  1936 
  1937 * reimplemented type inference for greater efficiency, better error
  1938 messages and clean internal interface;
  1939 
  1940 * prlim command for dealing with lots of subgoals (an easier way of
  1941 setting goals_limit);
  1942 
  1943 
  1944 *** Syntax ***
  1945 
  1946 * supports alternative (named) syntax tables (parser and pretty
  1947 printer); internal interface is provided by add_modesyntax(_i);
  1948 
  1949 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1950 be used in conjunction with the Isabelle symbol font; uses the
  1951 "symbols" syntax table;
  1952 
  1953 * added token_translation interface (may translate name tokens in
  1954 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1955 the current print_mode); IMPORTANT: user print translation functions
  1956 are responsible for marking newly introduced bounds
  1957 (Syntax.mark_boundT);
  1958 
  1959 * token translations for modes "xterm" and "xterm_color" that display
  1960 names in bold, underline etc. or colors (which requires a color
  1961 version of xterm);
  1962 
  1963 * infixes may now be declared with names independent of their syntax;
  1964 
  1965 * added typed_print_translation (like print_translation, but may
  1966 access type of constant);
  1967 
  1968 
  1969 *** Classical Reasoner ***
  1970 
  1971 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1972 some limitations.  Blast_tac...
  1973   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1974   + ignores elimination rules that don't have the correct format
  1975         (the conclusion MUST be a formula variable)
  1976   + ignores types, which can make HOL proofs fail
  1977   + rules must not require higher-order unification, e.g. apply_type in ZF
  1978     [message "Function Var's argument not a bound variable" relates to this]
  1979   + its proof strategy is more general but can actually be slower
  1980 
  1981 * substitution with equality assumptions no longer permutes other
  1982 assumptions;
  1983 
  1984 * minor changes in semantics of addafter (now called addaltern); renamed
  1985 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1986 (and access functions for it);
  1987 
  1988 * improved combination of classical reasoner and simplifier:
  1989   + functions for handling clasimpsets
  1990   + improvement of addss: now the simplifier is called _after_ the
  1991     safe steps.
  1992   + safe variant of addss called addSss: uses safe simplifications
  1993     _during_ the safe steps. It is more complete as it allows multiple
  1994     instantiations of unknowns (e.g. with slow_tac).
  1995 
  1996 *** Simplifier ***
  1997 
  1998 * added interface for simplification procedures (functions that
  1999 produce *proven* rewrite rules on the fly, depending on current
  2000 redex);
  2001 
  2002 * ordering on terms as parameter (used for ordered rewriting);
  2003 
  2004 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2005 
  2006 * the solver is now split into a safe and an unsafe part.
  2007 This should be invisible for the normal user, except that the
  2008 functions setsolver and addsolver have been renamed to setSolver and
  2009 addSolver; added safe_asm_full_simp_tac;
  2010 
  2011 
  2012 *** HOL ***
  2013 
  2014 * a generic induction tactic `induct_tac' which works for all datatypes and
  2015 also for type `nat';
  2016 
  2017 * a generic case distinction tactic `exhaust_tac' which works for all
  2018 datatypes and also for type `nat';
  2019 
  2020 * each datatype comes with a function `size';
  2021 
  2022 * patterns in case expressions allow tuple patterns as arguments to
  2023 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2024 
  2025 * primrec now also works with type nat;
  2026 
  2027 * recdef: a new declaration form, allows general recursive functions to be
  2028 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2029 
  2030 * the constant for negation has been renamed from "not" to "Not" to
  2031 harmonize with FOL, ZF, LK, etc.;
  2032 
  2033 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2034 infinite lists;
  2035 
  2036 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2037 
  2038 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2039 problems in commutative rings, using axiomatic type classes for + and *;
  2040 
  2041 * more examples in HOL/MiniML and HOL/Auth;
  2042 
  2043 * more default rewrite rules for quantifiers, union/intersection;
  2044 
  2045 * a new constant `arbitrary == @x.False';
  2046 
  2047 * HOLCF/IOA replaces old HOL/IOA;
  2048 
  2049 * HOLCF changes: derived all rules and arities
  2050   + axiomatic type classes instead of classes
  2051   + typedef instead of faking type definitions
  2052   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2053   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2054   + eliminated the types void, one, tr
  2055   + use unit lift and bool lift (with translations) instead of one and tr
  2056   + eliminated blift from Lift3.thy (use Def instead of blift)
  2057   all eliminated rules are derived as theorems --> no visible changes ;
  2058 
  2059 
  2060 *** ZF ***
  2061 
  2062 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2063 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2064 as ZF_cs addSIs [equalityI];
  2065 
  2066 
  2067 
  2068 New in Isabelle94-7 (November 96)
  2069 ---------------------------------
  2070 
  2071 * allowing negative levels (as offsets) in prlev and choplev;
  2072 
  2073 * super-linear speedup for large simplifications;
  2074 
  2075 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2076 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2077 FAIL); can suppress it using the command Delsimps (ex_simps @
  2078 all_simps); De Morgan laws are also now included, by default;
  2079 
  2080 * improved printing of ==>  :  ~:
  2081 
  2082 * new object-logic "Sequents" adds linear logic, while replacing LK
  2083 and Modal (thanks to Sara Kalvala);
  2084 
  2085 * HOL/Auth: correctness proofs for authentication protocols;
  2086 
  2087 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2088 examples on HOL/Auth);
  2089 
  2090 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2091 the rewriter and classical reasoner simultaneously;
  2092 
  2093 * function uresult no longer returns theorems in "standard" format;
  2094 regain previous version by: val uresult = standard o uresult;
  2095 
  2096 
  2097 
  2098 New in Isabelle94-6
  2099 -------------------
  2100 
  2101 * oracles -- these establish an interface between Isabelle and trusted
  2102 external reasoners, which may deliver results as theorems;
  2103 
  2104 * proof objects (in particular record all uses of oracles);
  2105 
  2106 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2107 
  2108 * "constdefs" section in theory files;
  2109 
  2110 * "primrec" section (HOL) no longer requires names;
  2111 
  2112 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2113 
  2114 
  2115 
  2116 New in Isabelle94-5
  2117 -------------------
  2118 
  2119 * reduced space requirements;
  2120 
  2121 * automatic HTML generation from theories;
  2122 
  2123 * theory files no longer require "..." (quotes) around most types;
  2124 
  2125 * new examples, including two proofs of the Church-Rosser theorem;
  2126 
  2127 * non-curried (1994) version of HOL is no longer distributed;
  2128 
  2129 
  2130 
  2131 New in Isabelle94-4
  2132 -------------------
  2133 
  2134 * greatly reduced space requirements;
  2135 
  2136 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2137 
  2138 * searchable theorem database (see the section "Retrieving theorems" on
  2139 page 8 of the Reference Manual);
  2140 
  2141 * new examples, including Grabczewski's monumental case study of the
  2142 Axiom of Choice;
  2143 
  2144 * The previous version of HOL renamed to Old_HOL;
  2145 
  2146 * The new version of HOL (previously called CHOL) uses a curried syntax
  2147 for functions.  Application looks like f a b instead of f(a,b);
  2148 
  2149 * Mutually recursive inductive definitions finally work in HOL;
  2150 
  2151 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2152 translates to the operator "split";
  2153 
  2154 
  2155 
  2156 New in Isabelle94-3
  2157 -------------------
  2158 
  2159 * new infix operator, addss, allowing the classical reasoner to
  2160 perform simplification at each step of its search.  Example:
  2161         fast_tac (cs addss ss)
  2162 
  2163 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2164 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2165 look like (a,b) instead of <a,b>;
  2166 
  2167 * PLEASE NOTE: CHOL will eventually replace HOL!
  2168 
  2169 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2170 It translates to the operator "split".  A new theory of integers is available;
  2171 
  2172 * In ZF, integer numerals now denote two's-complement binary integers.
  2173 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2174 
  2175 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2176 of the Axiom of Choice;
  2177 
  2178 
  2179 
  2180 New in Isabelle94-2
  2181 -------------------
  2182 
  2183 * Significantly faster resolution;
  2184 
  2185 * the different sections in a .thy file can now be mixed and repeated
  2186 freely;
  2187 
  2188 * Database of theorems for FOL, HOL and ZF.  New
  2189 commands including qed, qed_goal and bind_thm store theorems in the database.
  2190 
  2191 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2192 a given theory (thms_of), or find out what theory a theorem was proved in
  2193 (theory_of_thm);
  2194 
  2195 * Bugs fixed in the inductive definition and datatype packages;
  2196 
  2197 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2198 and HOL_dup_cs obsolete;
  2199 
  2200 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2201 have been removed;
  2202 
  2203 * Simpler definition of function space in ZF;
  2204 
  2205 * new results about cardinal and ordinal arithmetic in ZF;
  2206 
  2207 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2208 types;
  2209 
  2210 
  2211 $Id$