NEWS
author wenzelm
Thu Feb 28 21:30:26 2002 +0100 (2002-02-28)
changeset 12984 6071200efbf6
parent 12964 2ac9265b2cd5
child 13023 f869b6822006
permissions -rw-r--r--
fixed date;
     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/Provers/classical: simplified integration with pure rule
   155 attributes and methods; the classical "intro?/elim?/dest?"
   156 declarations coincide with the pure ones; the "rule" method no longer
   157 includes classically swapped intros; "intro" and "elim" methods no
   158 longer pick rules from the context; also got rid of ML declarations
   159 AddXIs/AddXEs/AddXDs; all of this has some potential for
   160 INCOMPATIBILITY;
   161 
   162 * Provers/classical: attribute 'swapped' produces classical inversions
   163 of introduction rules;
   164 
   165 * Provers/simplifier: 'simplified' attribute may refer to explicit
   166 rules instead of full simplifier context; 'iff' attribute handles
   167 conditional rules;
   168 
   169 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   170 
   171 * HOL: 'recdef' now fails on unfinished automated proofs, use
   172 "(permissive)" option to recover old behavior;
   173 
   174 * HOL: 'inductive' no longer features separate (collective) attributes
   175 for 'intros' (was found too confusing);
   176 
   177 * HOL: properly declared induction rules less_induct and
   178 wf_induct_rule;
   179 
   180 
   181 *** HOL ***
   182 
   183 * HOL: moved over to sane numeral syntax; the new policy is as
   184 follows:
   185 
   186   - 0 and 1 are polymorphic constants, which are defined on any
   187   numeric type (nat, int, real etc.);
   188 
   189   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   190   binary representation internally;
   191 
   192   - type nat has special constructor Suc, and generally prefers Suc 0
   193   over 1::nat and Suc (Suc 0) over 2::nat;
   194 
   195 This change may cause significant problems of INCOMPATIBILITY; here
   196 are some hints on converting existing sources:
   197 
   198   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   199   entities, so expressions involving "-" (unary or binary minus) need
   200   to be spaced properly;
   201 
   202   - existing occurrences of "1" may need to be constraint "1::nat" or
   203   even replaced by Suc 0; similar for old "2";
   204 
   205   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   206 
   207   - remove all special provisions on numerals in proofs;
   208 
   209 * HOL: simp rules nat_number_of expand numerals on nat to Suc/0
   210 representation (depends on bin_arith_simps in the default context);
   211 
   212 * HOL: symbolic syntax for x^2 (numeral 2);
   213 
   214 * HOL: the class of all HOL types is now called "type" rather than
   215 "term"; INCOMPATIBILITY, need to adapt references to this type class
   216 in axclass/classes, instance/arities, and (usually rare) occurrences
   217 in typings (of consts etc.); internally the class is called
   218 "HOL.type", ML programs should refer to HOLogic.typeS;
   219 
   220 * HOL/record package improvements:
   221   - new derived operations "fields" to build a partial record section,
   222     "extend" to promote a fixed record to a record scheme, and
   223     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   224     declared as simp by default;
   225   - shared operations ("more", "fields", etc.) now need to be always
   226     qualified) --- potential INCOMPATIBILITY;
   227   - removed "make_scheme" operations (use "make" with "extend") --
   228     INCOMPATIBILITY;
   229   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   230   - provides cases/induct rules for use with corresponding Isar
   231     methods (for concrete records, record schemes, concrete more
   232     parts, and schematic more parts -- in that order);
   233   - internal definitions directly based on a light-weight abstract
   234     theory of product types over typedef rather than datatype;
   235 
   236 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   237 
   238 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   239 (beware of argument permutation!);
   240 
   241 * HOL: linorder_less_split superseded by linorder_cases;
   242 
   243 * HOL/List: "nodups" renamed to "distinct";
   244 
   245 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   246 to peripheral theory "Hilbert_Choice";
   247 
   248 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   249 in this (rare) case use:
   250 
   251   delSWrapper "split_all_tac"
   252   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   253 
   254 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   255 MAY FAIL;
   256 
   257 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   258 Isabelle's type classes, ^ on functions and relations has too general
   259 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   260 necessary to attach explicit type constraints;
   261 
   262 * HOL/Relation: the prefix name of the infix "O" has been changed from
   263 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   264 renamed accordingly (eg "compI" -> "rel_compI").
   265 
   266 * HOL: syntax translations now work properly with numerals and records
   267 expressions;
   268 
   269 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   270 of "lam" -- INCOMPATIBILITY;
   271 
   272 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   273 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   274 renamed "Product_Type.unit";
   275 
   276 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   277 
   278 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   279 the "cases" method);
   280 
   281 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   282 Florian Kammüller);
   283 
   284 * HOL/IMP: updated and converted to new-style theory format; several
   285 parts turned into readable document, with proper Isar proof texts and
   286 some explanations (by Gerwin Klein);
   287 
   288 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   289 
   290 * HOL-Hyperreal is now a logic image;
   291 
   292 
   293 *** HOLCF ***
   294 
   295 * Isar: consts/constdefs supports mixfix syntax for continuous
   296 operations;
   297 
   298 * Isar: domain package adapted to new-style theory format, e.g. see
   299 HOLCF/ex/Dnat.thy;
   300 
   301 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   302 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   303 lift.induct_tac, always use UU instead of Undef;
   304 
   305 * HOLCF/IMP: updated and converted to new-style theory;
   306 
   307 
   308 *** ZF ***
   309 
   310 * Isar: proper integration of logic-specific tools and packages,
   311 including theory commands '(co)inductive', '(co)datatype',
   312 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   313 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   314 
   315 * theory Main no longer includes AC; for the Axiom of Choice, base
   316 your theory on Main_ZFC;
   317 
   318 * the integer library now covers quotients and remainders, with many
   319 laws relating division to addition, multiplication, etc.;
   320 
   321 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   322 typeless version of the formalism;
   323 
   324 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory format;
   325 
   326 * ZF/Induct: new directory for examples of inductive definitions,
   327 including theory Multiset for multiset orderings; converted to
   328 new-style theory format;
   329 
   330 * Many new theorems about lists, ordinals, etc.;
   331 
   332 
   333 *** General ***
   334 
   335 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   336 variable proof controls level of detail: 0 = no proofs (only oracle
   337 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   338 also ref manual for further ML interfaces;
   339 
   340 * Pure/axclass: removed obsolete ML interface
   341 goal_subclass/goal_arity;
   342 
   343 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   344 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   345 separate tokens, so expressions involving minus need to be spaced
   346 properly;
   347 
   348 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   349 rather than "infixl" or "infixr";
   350 
   351 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   352 sort constraint specifications in type inference; e.g. "x::_::foo"
   353 ensures that the type of "x" is of sort "foo" (but not necessarily a
   354 type variable);
   355 
   356 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   357 control output of nested => (types); the default behavior is
   358 "type_brackets";
   359 
   360 * Pure/syntax: builtin parse translation for "_constify" turns valued
   361 tokens into AST constants;
   362 
   363 * Pure/syntax: prefer later declarations of translations and print
   364 translation functions; potential INCOMPATIBILITY: need to reverse
   365 multiple declarations for same syntax element constant;
   366 
   367 * Pure/show_hyps reset by default (in accordance to existing Isar
   368 practice);
   369 
   370 * Provers/classical: renamed addaltern to addafter, addSaltern to
   371 addSafter;
   372 
   373 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   374 as well;
   375 
   376 * system: tested support for MacOS X; should be able to get Isabelle +
   377 Proof General to work in a plain Terminal after installing Poly/ML
   378 (e.g. from the Isabelle distribution area) and GNU bash alone
   379 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   380 support requires further installations, e.g. from
   381 http://fink.sourceforge.net/);
   382 
   383 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   384 
   385 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   386 of 40 MB), cf. ML_OPTIONS;
   387 
   388 * system: Proof General keywords specification is now part of the
   389 Isabelle distribution (see etc/isar-keywords.el);
   390 
   391 * system: support for persistent Proof General sessions (refrain from
   392 outdating all loaded theories on startup); user may create writable
   393 logic images like this: ``isabelle -q HOL Test'';
   394 
   395 * system: smart selection of Isabelle process versus Isabelle
   396 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   397 run both "isabelle" and "Isabelle" even if file names are badly
   398 damaged (executable inspects the case of the first letter of its own
   399 name); added separate "isabelle-process" and "isabelle-interface";
   400 
   401 * system: refrain from any attempt at filtering input streams; no
   402 longer support ``8bit'' encoding of old isabelle font, instead proper
   403 iso-latin characters may now be used; the related isatools
   404 "symbolinput" and "nonascii" have disappeared as well;
   405 
   406 * system: removed old "xterm" interface (the print modes "xterm" and
   407 "xterm_color" are still available for direct use in a suitable
   408 terminal);
   409 
   410 
   411 
   412 New in Isabelle99-2 (February 2001)
   413 -----------------------------------
   414 
   415 *** Overview of INCOMPATIBILITIES ***
   416 
   417 * HOL: please note that theories in the Library and elsewhere often use the
   418 new-style (Isar) format; to refer to their theorems in an ML script you must
   419 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   420 
   421 * HOL: inductive package no longer splits induction rule aggressively,
   422 but only as far as specified by the introductions given; the old
   423 format may be recovered via ML function complete_split_rule or attribute
   424 'split_rule (complete)';
   425 
   426 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   427 gfp_Tarski to gfp_unfold;
   428 
   429 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   430 
   431 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   432 relation); infix "^^" has been renamed "``"; infix "``" has been
   433 renamed "`"; "univalent" has been renamed "single_valued";
   434 
   435 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   436 operation;
   437 
   438 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   439 
   440 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   441 
   442 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   443 consequence, it is no longer monotonic wrt. the local goal context
   444 (which is now passed through the inductive cases);
   445 
   446 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   447 \<gg> to \<ggreater>;
   448 
   449 
   450 *** Document preparation ***
   451 
   452 * \isabellestyle{NAME} selects version of Isabelle output (currently
   453 available: are "it" for near math-mode best-style output, "sl" for
   454 slanted text style, and "tt" for plain type-writer; if no
   455 \isabellestyle command is given, output is according to slanted
   456 type-writer);
   457 
   458 * support sub/super scripts (for single symbols only), input syntax is
   459 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   460 
   461 * some more standard symbols; see Appendix A of the system manual for
   462 the complete list of symbols defined in isabellesym.sty;
   463 
   464 * improved isabelle style files; more abstract symbol implementation
   465 (should now use \isamath{...} and \isatext{...} in custom symbol
   466 definitions);
   467 
   468 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   469 state; Note that presentation of goal states does not conform to
   470 actual human-readable proof documents.  Please do not include goal
   471 states into document output unless you really know what you are doing!
   472 
   473 * proper indentation of antiquoted output with proportional LaTeX
   474 fonts;
   475 
   476 * no_document ML operator temporarily disables LaTeX document
   477 generation;
   478 
   479 * isatool unsymbolize tunes sources for plain ASCII communication;
   480 
   481 
   482 *** Isar ***
   483 
   484 * Pure: Isar now suffers initial goal statements to contain unbound
   485 schematic variables (this does not conform to actual readable proof
   486 documents, due to unpredictable outcome and non-compositional proof
   487 checking); users who know what they are doing may use schematic goals
   488 for Prolog-style synthesis of proven results;
   489 
   490 * Pure: assumption method (an implicit finishing) now handles actual
   491 rules as well;
   492 
   493 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   494 initial goal, declare "that" only as Pure intro (only for single
   495 steps); the "that" rule assumption may now be involved in implicit
   496 finishing, thus ".." becomes a feasible for trivial obtains;
   497 
   498 * Pure: default proof step now includes 'intro_classes'; thus trivial
   499 instance proofs may be performed by "..";
   500 
   501 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   502 statements as well;
   503 
   504 * Pure: more robust selection of calculational rules;
   505 
   506 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   507 rule (as well as the assumption rule);
   508 
   509 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   510 lemmas, using the graph browser tool;
   511 
   512 * Pure: predict failure of "show" in interactive mode;
   513 
   514 * Pure: 'thms_containing' now takes actual terms as arguments;
   515 
   516 * HOL: improved method 'induct' --- now handles non-atomic goals
   517 (potential INCOMPATIBILITY); tuned error handling;
   518 
   519 * HOL: cases and induct rules now provide explicit hints about the
   520 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   521 any remaining facts are inserted into the goal verbatim;
   522 
   523 * HOL: local contexts (aka cases) may now contain term bindings as
   524 well; the 'cases' and 'induct' methods new provide a ?case binding for
   525 the result to be shown in each case;
   526 
   527 * HOL: added 'recdef_tc' command;
   528 
   529 * isatool convert assists in eliminating legacy ML scripts;
   530 
   531 
   532 *** HOL ***
   533 
   534 * HOL/Library: a collection of generic theories to be used together
   535 with main HOL; the theory loader path already includes this directory
   536 by default; the following existing theories have been moved here:
   537 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   538 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   539 
   540 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   541 modelling and verification task performed in Isabelle/HOL +
   542 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   543 
   544 * HOL/Algebra: special summation operator SUM no longer exists, it has
   545 been replaced by setsum; infix 'assoc' now has priority 50 (like
   546 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   547 'domain', this makes the theory consistent with mathematical
   548 literature;
   549 
   550 * HOL basics: added overloaded operations "inverse" and "divide"
   551 (infix "/"), syntax for generic "abs" operation, generic summation
   552 operator \<Sum>;
   553 
   554 * HOL/typedef: simplified package, provide more useful rules (see also
   555 HOL/subset.thy);
   556 
   557 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   558 now expressed as a proper nested rule (old-style tactic scripts may
   559 require atomize_strip_tac to cope with non-atomic premises);
   560 
   561 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   562 to "split_conv" (old name still available for compatibility);
   563 
   564 * HOL: improved concrete syntax for strings (e.g. allows translation
   565 rules with string literals);
   566 
   567 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   568  and Fleuriot's mechanization of analysis, including the transcendental
   569  functions for the reals;
   570 
   571 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   572 
   573 
   574 *** CTT ***
   575 
   576 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   577 "lam" is displayed as TWO lambda-symbols
   578 
   579 * CTT: theory Main now available, containing everything (that is, Bool
   580 and Arith);
   581 
   582 
   583 *** General ***
   584 
   585 * Pure: the Simplifier has been implemented properly as a derived rule
   586 outside of the actual kernel (at last!); the overall performance
   587 penalty in practical applications is about 50%, while reliability of
   588 the Isabelle inference kernel has been greatly improved;
   589 
   590 * print modes "brackets" and "no_brackets" control output of nested =>
   591 (types) and ==> (props); the default behaviour is "brackets";
   592 
   593 * Provers: fast_tac (and friends) now handle actual object-logic rules
   594 as assumptions as well;
   595 
   596 * system: support Poly/ML 4.0;
   597 
   598 * system: isatool install handles KDE version 1 or 2;
   599 
   600 
   601 
   602 New in Isabelle99-1 (October 2000)
   603 ----------------------------------
   604 
   605 *** Overview of INCOMPATIBILITIES ***
   606 
   607 * HOL: simplification of natural numbers is much changed; to partly
   608 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   609 issue the following ML commands:
   610 
   611   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   612   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   613 
   614 * HOL: simplification no longer dives into case-expressions; this is
   615 controlled by "t.weak_case_cong" for each datatype t;
   616 
   617 * HOL: nat_less_induct renamed to less_induct;
   618 
   619 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   620 fixsome to patch .thy and .ML sources automatically;
   621 
   622   select_equality  -> some_equality
   623   select_eq_Ex     -> some_eq_ex
   624   selectI2EX       -> someI2_ex
   625   selectI2         -> someI2
   626   selectI          -> someI
   627   select1_equality -> some1_equality
   628   Eps_sym_eq       -> some_sym_eq_trivial
   629   Eps_eq           -> some_eq_trivial
   630 
   631 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   632 
   633 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   634 instead);
   635 
   636 * HOL: the recursion equations generated by 'recdef' are now called
   637 f.simps instead of f.rules;
   638 
   639 * HOL: qed_spec_mp now also handles bounded ALL as well;
   640 
   641 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   642 sometimes be needed;
   643 
   644 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   645 
   646 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   647 
   648 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   649 product is now "<*>" instead of "Times"; the lexicographic product is
   650 now "<*lex*>" instead of "**";
   651 
   652 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   653 of main HOL, but was unused); better use HOL's datatype package;
   654 
   655 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   656 the old syntax may be recovered as follows:
   657 
   658   syntax (symbols)
   659     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   660       (infixl "\\<oplus>" 100)
   661 
   662 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   663 
   664 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   665 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   666 internally;
   667 
   668 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   669 changed from A/r to A//r;
   670 
   671 * ZF: new treatment of arithmetic (nat & int) may break some old
   672 proofs;
   673 
   674 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   675 rulify -> rule_format, elimify -> elim_format, ...);
   676 
   677 * Isar/Provers: intro/elim/dest attributes changed; renamed
   678 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   679 should have to change intro!! to intro? only); replaced "delrule" by
   680 "rule del";
   681 
   682 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   683 
   684 * Provers: strengthened force_tac by using new first_best_tac;
   685 
   686 * LaTeX document preparation: several changes of isabelle.sty (see
   687 lib/texinputs);
   688 
   689 
   690 *** Document preparation ***
   691 
   692 * formal comments (text blocks etc.) in new-style theories may now
   693 contain antiquotations of thm/prop/term/typ/text to be presented
   694 according to latex print mode; concrete syntax is like this:
   695 @{term[show_types] "f(x) = a + x"};
   696 
   697 * isatool mkdir provides easy setup of Isabelle session directories,
   698 including proper document sources;
   699 
   700 * generated LaTeX sources are now deleted after successful run
   701 (isatool document -c); may retain a copy somewhere else via -D option
   702 of isatool usedir;
   703 
   704 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   705 style files, achieving self-contained LaTeX sources and simplifying
   706 LaTeX debugging;
   707 
   708 * old-style theories now produce (crude) LaTeX output as well;
   709 
   710 * browser info session directories are now self-contained (may be put
   711 on WWW server seperately); improved graphs of nested sessions; removed
   712 graph for 'all sessions';
   713 
   714 * several improvements in isabelle style files; \isabellestyle{it}
   715 produces fake math mode output; \isamarkupheader is now \section by
   716 default; see lib/texinputs/isabelle.sty etc.;
   717 
   718 
   719 *** Isar ***
   720 
   721 * Isar/Pure: local results and corresponding term bindings are now
   722 subject to Hindley-Milner polymorphism (similar to ML); this
   723 accommodates incremental type-inference very nicely;
   724 
   725 * Isar/Pure: new derived language element 'obtain' supports
   726 generalized existence reasoning;
   727 
   728 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   729 support accumulation of results, without applying any rules yet;
   730 useful to collect intermediate results without explicit name
   731 references, and for use with transitivity rules with more than 2
   732 premises;
   733 
   734 * Isar/Pure: scalable support for case-analysis type proofs: new
   735 'case' language element refers to local contexts symbolically, as
   736 produced by certain proof methods; internally, case names are attached
   737 to theorems as "tags";
   738 
   739 * Isar/Pure: theory command 'hide' removes declarations from
   740 class/type/const name spaces;
   741 
   742 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   743 indicate potential overloading;
   744 
   745 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   746 
   747 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   748 "{a,b,c}" instead of {a,b,c};
   749 
   750 * Isar/Pure now provides its own version of intro/elim/dest
   751 attributes; useful for building new logics, but beware of confusion
   752 with the version in Provers/classical;
   753 
   754 * Isar/Pure: the local context of (non-atomic) goals is provided via
   755 case name 'antecedent';
   756 
   757 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   758 to the current context is now done automatically);
   759 
   760 * Isar/Pure: theory command 'method_setup' provides a simple interface
   761 for definining proof methods in ML;
   762 
   763 * Isar/Provers: intro/elim/dest attributes changed; renamed
   764 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   765 most cases, one should have to change intro!! to intro? only);
   766 replaced "delrule" by "rule del";
   767 
   768 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   769 'symmetric' attribute (the latter supercedes [RS sym]);
   770 
   771 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   772 method modifier); 'simp' method: 'only:' modifier removes loopers as
   773 well (including splits);
   774 
   775 * Isar/Provers: Simplifier and Classical methods now support all kind
   776 of modifiers used in the past, including 'cong', 'iff', etc.
   777 
   778 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   779 of Simplifier and Classical reasoner);
   780 
   781 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   782 now support named cases; major packages (inductive, datatype, primrec,
   783 recdef) support case names and properly name parameters;
   784 
   785 * Isar/HOL: new transitivity rules for substitution in inequalities --
   786 monotonicity conditions are extracted to be proven at end of
   787 calculations;
   788 
   789 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   790 method anyway;
   791 
   792 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   793 split_if split_if_asm; datatype package provides theorems foo.splits =
   794 foo.split foo.split_asm for each datatype;
   795 
   796 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   797 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   798 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   799 use "(cases (simplified))" method in proper proof texts);
   800 
   801 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   802 
   803 * Isar: names of theorems etc. may be natural numbers as well;
   804 
   805 * Isar: 'pr' command: optional arguments for goals_limit and
   806 ProofContext.prems_limit; no longer prints theory contexts, but only
   807 proof states;
   808 
   809 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   810 additional print modes to be specified; e.g. "pr(latex)" will print
   811 proof state according to the Isabelle LaTeX style;
   812 
   813 * Isar: improved support for emulating tactic scripts, including proof
   814 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   815 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   816 (for HOL datatypes);
   817 
   818 * Isar: simplified (more robust) goal selection of proof methods: 1st
   819 goal, all goals, or explicit goal specifier (tactic emulation); thus
   820 'proof method scripts' have to be in depth-first order;
   821 
   822 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   823 
   824 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   825 should instead use individual commands for printing items
   826 (print_commands, print_methods etc.);
   827 
   828 * Isar: added 'nothing' --- the empty list of theorems;
   829 
   830 
   831 *** HOL ***
   832 
   833 * HOL/MicroJava: formalization of a fragment of Java, together with a
   834 corresponding virtual machine and a specification of its bytecode
   835 verifier and a lightweight bytecode verifier, including proofs of
   836 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   837 Cornelia Pusch (see also the homepage of project Bali at
   838 http://isabelle.in.tum.de/Bali/);
   839 
   840 * HOL/Algebra: new theory of rings and univariate polynomials, by
   841 Clemens Ballarin;
   842 
   843 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   844 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   845 Rasmussen;
   846 
   847 * HOL/Lattice: fundamental concepts of lattice theory and order
   848 structures, including duals, properties of bounds versus algebraic
   849 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   850 Theorem for complete lattices etc.; may also serve as a demonstration
   851 for abstract algebraic reasoning using axiomatic type classes, and
   852 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   853 
   854 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   855 von Oheimb;
   856 
   857 * HOL/IMPP: extension of IMP with local variables and mutually
   858 recursive procedures, by David von Oheimb;
   859 
   860 * HOL/Lambda: converted into new-style theory and document;
   861 
   862 * HOL/ex/Multiquote: example of multiple nested quotations and
   863 anti-quotations -- basically a generalized version of de-Bruijn
   864 representation; very useful in avoiding lifting of operations;
   865 
   866 * HOL/record: added general record equality rule to simpset; fixed
   867 select-update simplification procedure to handle extended records as
   868 well; admit "r" as field name;
   869 
   870 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   871 other numeric types and also as the identity of groups, rings, etc.;
   872 
   873 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   874 Types nat and int belong to this axclass;
   875 
   876 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   877    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   878    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   879   two terms #m*u and #n*u are replaced by #(m+n)*u
   880     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   881   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   882     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   883 
   884 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   885 powerful prover for predicate logic but knows nothing of clasets; see
   886 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   887 
   888 * HOL: new version of "case_tac" subsumes both boolean case split and
   889 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   890 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   891 
   892 * HOL: simplification no longer dives into case-expressions: only the
   893 selector expression is simplified, but not the remaining arms; to
   894 enable full simplification of case-expressions for datatype t, you may
   895 remove t.weak_case_cong from the simpset, either globally (Delcongs
   896 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   897 
   898 * HOL/recdef: the recursion equations generated by 'recdef' for
   899 function 'f' are now called f.simps instead of f.rules; if all
   900 termination conditions are proved automatically, these simplification
   901 rules are added to the simpset, as in primrec; rules may be named
   902 individually as well, resulting in a separate list of theorems for
   903 each equation;
   904 
   905 * HOL/While is a new theory that provides a while-combinator. It
   906 permits the definition of tail-recursive functions without the
   907 provision of a termination measure. The latter is necessary once the
   908 invariant proof rule for while is applied.
   909 
   910 * HOL: new (overloaded) notation for the set of elements below/above
   911 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   912 
   913 * HOL: theorems impI, allI, ballI bound as "strip";
   914 
   915 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   916 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   917 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   918 
   919 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   920 
   921 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   922 main HOL, but was unused);
   923 
   924 * HOL: fewer consts declared as global (e.g. have to refer to
   925 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   926 
   927 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   928 in case of overlap with user translations (e.g. judgements over
   929 tuples); (note that the underlying logical represenation is still
   930 bogus);
   931 
   932 
   933 *** ZF ***
   934 
   935 * ZF: simplification automatically cancels common terms in arithmetic
   936 expressions over nat and int;
   937 
   938 * ZF: new treatment of nat to minimize type-checking: all operators
   939 coerce their operands to a natural number using the function natify,
   940 making the algebraic laws unconditional;
   941 
   942 * ZF: as above, for int: operators coerce their operands to an integer
   943 using the function intify;
   944 
   945 * ZF: the integer library now contains many of the usual laws for the
   946 orderings, including $<=, and monotonicity laws for $+ and $*;
   947 
   948 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   949 simplification;
   950 
   951 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   952 to the simplifier and classical reasoner simultaneously;
   953 
   954 
   955 *** General ***
   956 
   957 * Provers: blast_tac now handles actual object-logic rules as
   958 assumptions; note that auto_tac uses blast_tac internally as well;
   959 
   960 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   961 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   962 
   963 * Provers: delrules now handles destruct rules as well (no longer need
   964 explicit make_elim);
   965 
   966 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   967   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   968 use instead the strong form,
   969   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   970 in HOL, FOL and ZF the function cla_make_elim will create such rules
   971 from destruct-rules;
   972 
   973 * Provers: Simplifier.easy_setup provides a fast path to basic
   974 Simplifier setup for new object-logics;
   975 
   976 * Pure: AST translation rules no longer require constant head on LHS;
   977 
   978 * Pure: improved name spaces: ambiguous output is qualified; support
   979 for hiding of names;
   980 
   981 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   982 XSYMBOL_HOME; no longer need to do manual configuration in most
   983 situations;
   984 
   985 * system: compression of ML heaps images may now be controlled via -c
   986 option of isabelle and isatool usedir (currently only observed by
   987 Poly/ML);
   988 
   989 * system: isatool installfonts may handle X-Symbol fonts as well (very
   990 useful for remote X11);
   991 
   992 * system: provide TAGS file for Isabelle sources;
   993 
   994 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   995 order;
   996 
   997 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   998 timing flag supersedes proof_timing and Toplevel.trace;
   999 
  1000 * ML: new combinators |>> and |>>> for incremental transformations
  1001 with secondary results (e.g. certain theory extensions):
  1002 
  1003 * ML: PureThy.add_defs gets additional argument to indicate potential
  1004 overloading (usually false);
  1005 
  1006 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1007 results;
  1008 
  1009 
  1010 
  1011 New in Isabelle99 (October 1999)
  1012 --------------------------------
  1013 
  1014 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1015 
  1016 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1017 are no longer simplified.  (This allows the simplifier to unfold recursive
  1018 functional programs.)  To restore the old behaviour, declare
  1019 
  1020     Delcongs [if_weak_cong];
  1021 
  1022 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1023 complement;
  1024 
  1025 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1026 
  1027 * HOL/datatype: mutual_induct_tac no longer exists --
  1028   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1029 
  1030 * HOL/typedef: fixed type inference for representing set; type
  1031 arguments now have to occur explicitly on the rhs as type constraints;
  1032 
  1033 * ZF: The con_defs part of an inductive definition may no longer refer
  1034 to constants declared in the same theory;
  1035 
  1036 * HOL, ZF: the function mk_cases, generated by the inductive
  1037 definition package, has lost an argument.  To simplify its result, it
  1038 uses the default simpset instead of a supplied list of theorems.
  1039 
  1040 * HOL/List: the constructors of type list are now Nil and Cons;
  1041 
  1042 * Simplifier: the type of the infix ML functions
  1043         setSSolver addSSolver setSolver addSolver
  1044 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1045 for packaging solvers. A solver is created via
  1046         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1047 where the string argument is only a comment.
  1048 
  1049 
  1050 *** Proof tools ***
  1051 
  1052 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1053 decision procedure for linear arithmetic. Currently it is used for
  1054 types `nat', `int', and `real' in HOL (see below); it can, should and
  1055 will be instantiated for other types and logics as well.
  1056 
  1057 * The simplifier now accepts rewrite rules with flexible heads, eg
  1058      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1059   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1060   matching.
  1061 
  1062 
  1063 *** General ***
  1064 
  1065 * New Isabelle/Isar subsystem provides an alternative to traditional
  1066 tactical theorem proving; together with the ProofGeneral/isar user
  1067 interface it offers an interactive environment for developing human
  1068 readable proof documents (Isar == Intelligible semi-automated
  1069 reasoning); for further information see isatool doc isar-ref,
  1070 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1071 
  1072 * improved and simplified presentation of theories: better HTML markup
  1073 (including colors), graph views in several sizes; isatool usedir now
  1074 provides a proper interface for user theories (via -P option); actual
  1075 document preparation based on (PDF)LaTeX is available as well (for
  1076 new-style theories only); see isatool doc system for more information;
  1077 
  1078 * native support for Proof General, both for classic Isabelle and
  1079 Isabelle/Isar;
  1080 
  1081 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1082 using the graph browser tool;
  1083 
  1084 * Isabelle manuals now also available as PDF;
  1085 
  1086 * theory loader rewritten from scratch (may not be fully
  1087 bug-compatible); old loadpath variable has been replaced by show_path,
  1088 add_path, del_path, reset_path functions; new operations such as
  1089 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1090 isatool doc ref);
  1091 
  1092 * improved isatool install: option -k creates KDE application icon,
  1093 option -p DIR installs standalone binaries;
  1094 
  1095 * added ML_PLATFORM setting (useful for cross-platform installations);
  1096 more robust handling of platform specific ML images for SML/NJ;
  1097 
  1098 * the settings environment is now statically scoped, i.e. it is never
  1099 created again in sub-processes invoked from isabelle, isatool, or
  1100 Isabelle;
  1101 
  1102 * path element specification '~~' refers to '$ISABELLE_HOME';
  1103 
  1104 * in locales, the "assumes" and "defines" parts may be omitted if
  1105 empty;
  1106 
  1107 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1108 long arrows);
  1109 
  1110 * new print_mode "HTML";
  1111 
  1112 * new flag show_tags controls display of tags of theorems (which are
  1113 basically just comments that may be attached by some tools);
  1114 
  1115 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1116 mode and goal output format:
  1117 
  1118 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1119 244c244
  1120 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1121 ---
  1122 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1123 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1124 181c181
  1125 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1126 ---
  1127 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1128 
  1129 * function bind_thms stores lists of theorems (cf. bind_thm);
  1130 
  1131 * new shorthand tactics ftac, eatac, datac, fatac;
  1132 
  1133 * qed (and friends) now accept "" as result name; in that case the
  1134 theorem is not stored, but proper checks and presentation of the
  1135 result still apply;
  1136 
  1137 * theorem database now also indexes constants "Trueprop", "all",
  1138 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1139 
  1140 
  1141 *** HOL ***
  1142 
  1143 ** HOL arithmetic **
  1144 
  1145 * There are now decision procedures for linear arithmetic over nat and
  1146 int:
  1147 
  1148 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1149 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1150 are treated as atomic; subformulae not involving type `nat' or `int'
  1151 are ignored; quantified subformulae are ignored unless they are
  1152 positive universal or negative existential. The tactic has to be
  1153 invoked by hand and can be a little bit slow. In particular, the
  1154 running time is exponential in the number of occurrences of `min' and
  1155 `max', and `-' on `nat'.
  1156 
  1157 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1158 (negated) (in)equalities among the premises and the conclusion into
  1159 account (i.e. no compound formulae) and does not know about `min' and
  1160 `max', and `-' on `nat'. It is fast and is used automatically by the
  1161 simplifier.
  1162 
  1163 NB: At the moment, these decision procedures do not cope with mixed
  1164 nat/int formulae where the two parts interact, such as `m < n ==>
  1165 int(m) < int(n)'.
  1166 
  1167 * HOL/Numeral provides a generic theory of numerals (encoded
  1168 efficiently as bit strings); setup for types nat/int/real is in place;
  1169 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1170 int, existing theories and proof scripts may require a few additional
  1171 type constraints;
  1172 
  1173 * integer division and remainder can now be performed on constant
  1174 arguments;
  1175 
  1176 * many properties of integer multiplication, division and remainder
  1177 are now available;
  1178 
  1179 * An interface to the Stanford Validity Checker (SVC) is available through the
  1180 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1181 are proved automatically.  SVC must be installed separately, and its results
  1182 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1183 invocation of the underlying oracle).  For SVC see
  1184   http://verify.stanford.edu/SVC
  1185 
  1186 * IsaMakefile: the HOL-Real target now builds an actual image;
  1187 
  1188 
  1189 ** HOL misc **
  1190 
  1191 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1192 (in Isabelle/Isar) -- by Gertrud Bauer;
  1193 
  1194 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1195 analysis for assembly languages with subtypes;
  1196 
  1197 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1198 -- avoids syntactic ambiguities and treats state, transition, and
  1199 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1200 changed syntax and (many) tactics;
  1201 
  1202 * HOL/inductive: Now also handles more general introduction rules such
  1203   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1204   theorems are now maintained within the theory (maintained via the
  1205   "mono" attribute);
  1206 
  1207 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1208   (using function types) such as
  1209 
  1210   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1211 
  1212 * HOL/record: record_simproc (part of the default simpset) takes care
  1213 of selectors applied to updated records; record_split_tac is no longer
  1214 part of the default claset; update_defs may now be removed from the
  1215 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1216 
  1217   claset_ref () := claset() addSWrapper record_split_wrapper;
  1218   Delsimprocs [record_simproc]
  1219 
  1220 * HOL/typedef: fixed type inference for representing set; type
  1221 arguments now have to occur explicitly on the rhs as type constraints;
  1222 
  1223 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1224 names rather than an ML expression;
  1225 
  1226 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1227 supplied later.  Program schemes can be defined, such as
  1228     "While B C s = (if B s then While B C (C s) else s)"
  1229 where the well-founded relation can be chosen after B and C have been given.
  1230 
  1231 * HOL/List: the constructors of type list are now Nil and Cons;
  1232 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1233 course, ML tools referring to List.list.op # etc. have to be adapted;
  1234 
  1235 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1236 disabled by default; run isabelle with option -m HOL to get back to
  1237 the original Gordon/HOL-style output;
  1238 
  1239 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1240 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1241 
  1242 * HOL basic syntax simplified (more orthogonal): all variants of
  1243 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1244 Eps operator is provided as well: "SOME x. P[x]";
  1245 
  1246 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1247 
  1248 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1249 thus available for user theories;
  1250 
  1251 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1252 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1253 time;
  1254 
  1255 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1256 several times and then mp;
  1257 
  1258 
  1259 *** LK ***
  1260 
  1261 * the notation <<...>> is now available as a notation for sequences of
  1262 formulas;
  1263 
  1264 * the simplifier is now installed
  1265 
  1266 * the axiom system has been generalized (thanks to Soren Heilmann)
  1267 
  1268 * the classical reasoner now has a default rule database
  1269 
  1270 
  1271 *** ZF ***
  1272 
  1273 * new primrec section allows primitive recursive functions to be given
  1274 directly (as in HOL) over datatypes and the natural numbers;
  1275 
  1276 * new tactics induct_tac and exhaust_tac for induction (or case
  1277 analysis) over datatypes and the natural numbers;
  1278 
  1279 * the datatype declaration of type T now defines the recursor T_rec;
  1280 
  1281 * simplification automatically does freeness reasoning for datatype
  1282 constructors;
  1283 
  1284 * automatic type-inference, with AddTCs command to insert new
  1285 type-checking rules;
  1286 
  1287 * datatype introduction rules are now added as Safe Introduction rules
  1288 to the claset;
  1289 
  1290 * the syntax "if P then x else y" is now available in addition to
  1291 if(P,x,y);
  1292 
  1293 
  1294 *** Internal programming interfaces ***
  1295 
  1296 * tuned simplifier trace output; new flag debug_simp;
  1297 
  1298 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1299 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1300 
  1301 * AxClass.axclass_tac lost the theory argument;
  1302 
  1303 * tuned current_goals_markers semantics: begin / end goal avoids
  1304 printing empty lines;
  1305 
  1306 * removed prs and prs_fn hook, which was broken because it did not
  1307 include \n in its semantics, forcing writeln to add one
  1308 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1309 string -> unit if you really want to output text without newline;
  1310 
  1311 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1312 plain output, interface builders may have to enable 'isabelle_font'
  1313 mode to get Isabelle font glyphs as before;
  1314 
  1315 * refined token_translation interface; INCOMPATIBILITY: output length
  1316 now of type real instead of int;
  1317 
  1318 * theory loader actions may be traced via new ThyInfo.add_hook
  1319 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1320 your own database of information attached to *whole* theories -- as
  1321 opposed to intra-theory data slots offered via TheoryDataFun;
  1322 
  1323 * proper handling of dangling sort hypotheses (at last!);
  1324 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1325 extra sort hypotheses that can be witnessed from the type signature;
  1326 the force_strip_shyps flag is gone, any remaining shyps are simply
  1327 left in the theorem (with a warning issued by strip_shyps_warning);
  1328 
  1329 
  1330 
  1331 New in Isabelle98-1 (October 1998)
  1332 ----------------------------------
  1333 
  1334 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1335 
  1336 * several changes of automated proof tools;
  1337 
  1338 * HOL: major changes to the inductive and datatype packages, including
  1339 some minor incompatibilities of theory syntax;
  1340 
  1341 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1342 called `inj_on';
  1343 
  1344 * HOL: removed duplicate thms in Arith:
  1345   less_imp_add_less  should be replaced by  trans_less_add1
  1346   le_imp_add_le      should be replaced by  trans_le_add1
  1347 
  1348 * HOL: unary minus is now overloaded (new type constraints may be
  1349 required);
  1350 
  1351 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1352 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1353 now taken as an integer constant.
  1354 
  1355 * Pure: ML function 'theory_of' renamed to 'theory';
  1356 
  1357 
  1358 *** Proof tools ***
  1359 
  1360 * Simplifier:
  1361   1. Asm_full_simp_tac is now more aggressive.
  1362      1. It will sometimes reorient premises if that increases their power to
  1363         simplify.
  1364      2. It does no longer proceed strictly from left to right but may also
  1365         rotate premises to achieve further simplification.
  1366      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1367      old Asm_full_simp_tac in that it does not rotate premises.
  1368   2. The simplifier now knows a little bit about nat-arithmetic.
  1369 
  1370 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1371 allows for selected deletion of wrappers, by introduction of names for
  1372 wrapper functionals.  This implies that addbefore, addSbefore,
  1373 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1374 and that adding two tactics with the same name overwrites the first
  1375 one (emitting a warning).
  1376   type wrapper = (int -> tactic) -> (int -> tactic)
  1377   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1378   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1379   delWrapper, delSWrapper: claset *  string            -> claset
  1380   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1381 
  1382 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1383 semantics; addbefore now affects only the unsafe part of step_tac
  1384 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1385 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1386 by Force_tac;
  1387 
  1388 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1389 compWrapper; added safe wrapper (and access functions for it);
  1390 
  1391 * HOL/split_all_tac is now much faster and fails if there is nothing
  1392 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1393 and the names of the automatically generated variables have changed.
  1394 split_all_tac has moved within claset() from unsafe wrappers to safe
  1395 wrappers, which means that !!-bound variables are split much more
  1396 aggressively, and safe_tac and clarify_tac now split such variables.
  1397 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1398 Note: the same holds for record_split_tac, which does the job of
  1399 split_all_tac for record fields.
  1400 
  1401 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1402 permanently to the default simpset using Addsplits just like
  1403 Addsimps. They can be removed via Delsplits just like
  1404 Delsimps. Lower-case versions are also available.
  1405 
  1406 * HOL/Simplifier: The rule split_if is now part of the default
  1407 simpset. This means that the simplifier will eliminate all occurrences
  1408 of if-then-else in the conclusion of a goal. To prevent this, you can
  1409 either remove split_if completely from the default simpset by
  1410 `Delsplits [split_if]' or remove it in a specific call of the
  1411 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1412 other case splitting rules to/from the default simpset: every datatype
  1413 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1414 t is the name of the datatype).
  1415 
  1416 * Classical reasoner / Simplifier combination: new force_tac (and
  1417 derivatives Force_tac, force) combines rewriting and classical
  1418 reasoning (and whatever other tools) similarly to auto_tac, but is
  1419 aimed to solve the given subgoal completely.
  1420 
  1421 
  1422 *** General ***
  1423 
  1424 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1425 and `goalw': the theory is no longer needed as an explicit argument -
  1426 the current theory context is used; assumptions are no longer returned
  1427 at the ML-level unless one of them starts with ==> or !!; it is
  1428 recommended to convert to these new commands using isatool fixgoal
  1429 (backup your sources first!);
  1430 
  1431 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1432 the current theory context, and 'theory' to lookup stored theories;
  1433 
  1434 * new theory section 'locale' for declaring constants, assumptions and
  1435 definitions that have local scope;
  1436 
  1437 * new theory section 'nonterminals' for purely syntactic types;
  1438 
  1439 * new theory section 'setup' for generic ML setup functions
  1440 (e.g. package initialization);
  1441 
  1442 * the distribution now includes Isabelle icons: see
  1443 lib/logo/isabelle-{small,tiny}.xpm;
  1444 
  1445 * isatool install - install binaries with absolute references to
  1446 ISABELLE_HOME/bin;
  1447 
  1448 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1449 
  1450 * print mode 'emacs' reserved for Isamode;
  1451 
  1452 * support multiple print (ast) translations per constant name;
  1453 
  1454 * theorems involving oracles are now printed with a suffixed [!];
  1455 
  1456 
  1457 *** HOL ***
  1458 
  1459 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1460 
  1461 * HOL/inductive package reorganized and improved: now supports mutual
  1462 definitions such as
  1463 
  1464   inductive EVEN ODD
  1465     intrs
  1466       null "0 : EVEN"
  1467       oddI "n : EVEN ==> Suc n : ODD"
  1468       evenI "n : ODD ==> Suc n : EVEN"
  1469 
  1470 new theorem list "elims" contains an elimination rule for each of the
  1471 recursive sets; inductive definitions now handle disjunctive premises
  1472 correctly (also ZF);
  1473 
  1474 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1475 "mutual_induct" no longer exists - the induction rule is always
  1476 contained in "induct";
  1477 
  1478 
  1479 * HOL/datatype package re-implemented and greatly improved: now
  1480 supports mutually recursive datatypes such as
  1481 
  1482   datatype
  1483     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1484             | SUM ('a aexp) ('a aexp)
  1485             | DIFF ('a aexp) ('a aexp)
  1486             | NUM 'a
  1487   and
  1488     'a bexp = LESS ('a aexp) ('a aexp)
  1489             | AND ('a bexp) ('a bexp)
  1490             | OR ('a bexp) ('a bexp)
  1491 
  1492 as well as indirectly recursive datatypes such as
  1493 
  1494   datatype
  1495     ('a, 'b) term = Var 'a
  1496                   | App 'b ((('a, 'b) term) list)
  1497 
  1498 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1499 induction on mutually / indirectly recursive datatypes.
  1500 
  1501 Primrec equations are now stored in theory and can be accessed via
  1502 <function_name>.simps.
  1503 
  1504 INCOMPATIBILITIES:
  1505 
  1506   - Theories using datatypes must now have theory Datatype as an
  1507     ancestor.
  1508   - The specific <typename>.induct_tac no longer exists - use the
  1509     generic induct_tac instead.
  1510   - natE has been renamed to nat.exhaust - use exhaust_tac
  1511     instead of res_inst_tac ... natE. Note that the variable
  1512     names in nat.exhaust differ from the names in natE, this
  1513     may cause some "fragile" proofs to fail.
  1514   - The theorems split_<typename>_case and split_<typename>_case_asm
  1515     have been renamed to <typename>.split and <typename>.split_asm.
  1516   - Since default sorts of type variables are now handled correctly,
  1517     some datatype definitions may have to be annotated with explicit
  1518     sort constraints.
  1519   - Primrec definitions no longer require function name and type
  1520     of recursive argument.
  1521 
  1522 Consider using isatool fixdatatype to adapt your theories and proof
  1523 scripts to the new package (backup your sources first!).
  1524 
  1525 
  1526 * HOL/record package: considerably improved implementation; now
  1527 includes concrete syntax for record types, terms, updates; theorems
  1528 for surjective pairing and splitting !!-bound record variables; proof
  1529 support is as follows:
  1530 
  1531   1) standard conversions (selectors or updates applied to record
  1532 constructor terms) are part of the standard simpset;
  1533 
  1534   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1535 made part of standard simpset and claset via addIffs;
  1536 
  1537   3) a tactic for record field splitting (record_split_tac) is part of
  1538 the standard claset (addSWrapper);
  1539 
  1540 To get a better idea about these rules you may retrieve them via
  1541 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1542 the name of your record type.
  1543 
  1544 The split tactic 3) conceptually simplifies by the following rule:
  1545 
  1546   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1547 
  1548 Thus any record variable that is bound by meta-all will automatically
  1549 blow up into some record constructor term, consequently the
  1550 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1551 solve record problems automatically.
  1552 
  1553 
  1554 * reorganized the main HOL image: HOL/Integ and String loaded by
  1555 default; theory Main includes everything;
  1556 
  1557 * automatic simplification of integer sums and comparisons, using cancellation;
  1558 
  1559 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1560 
  1561 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1562 
  1563 * many new identities for unions, intersections, set difference, etc.;
  1564 
  1565 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1566 called split_if, split_split, split_sum_case and split_nat_case (to go
  1567 with add/delsplits);
  1568 
  1569 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1570 (?x::unit) = (); this is made part of the default simpset, which COULD
  1571 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1572 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1573 unit_abs_eta_conv is added in order to counter the effect of
  1574 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1575 %u.f();
  1576 
  1577 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1578 makes more sense);
  1579 
  1580 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1581   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1582   disjointness reasoning but breaking a few old proofs.
  1583 
  1584 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1585 to 'converse' from 'inverse' (for compatibility with ZF and some
  1586 literature);
  1587 
  1588 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1589 the well-founded relation;
  1590 
  1591 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1592     Compl A.  The "Compl" syntax remains available as input syntax for this
  1593     release ONLY.
  1594 
  1595 * HOL/Update: new theory of function updates:
  1596     f(a:=b) == %x. if x=a then b else f x
  1597 may also be iterated as in f(a:=b,c:=d,...);
  1598 
  1599 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1600 
  1601 * HOL/List:
  1602   - new function list_update written xs[i:=v] that updates the i-th
  1603     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1604   - new function `upt' written [i..j(] which generates the list
  1605     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1606     bound write [i..j], which is a shorthand for [i..j+1(].
  1607   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1608 
  1609 * HOL/Arith:
  1610   - removed 'pred' (predecessor) function;
  1611   - generalized some theorems about n-1;
  1612   - many new laws about "div" and "mod";
  1613   - new laws about greatest common divisors (see theory ex/Primes);
  1614 
  1615 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1616 instead of "inverse";
  1617 
  1618 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1619   of the multiset ordering;
  1620 
  1621 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1622   (not included by default);
  1623 
  1624 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1625 
  1626 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1627   programs, i.e. different program variables may have different types.
  1628 
  1629 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1630   [previously, this check worked only if the rewrite rule was unconditional]
  1631   Now rew can involve either definitions or equalities (either == or =).
  1632 
  1633 
  1634 *** ZF ***
  1635 
  1636 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1637   only the theorems proved on ZF.ML;
  1638 
  1639 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1640   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1641   disjointness reasoning but breaking a few old proofs.
  1642 
  1643 * ZF/Update: new theory of function updates
  1644     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1645   may also be iterated as in f(a:=b,c:=d,...);
  1646 
  1647 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1648 
  1649 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1650   [previously, this check worked only if the rewrite rule was unconditional]
  1651   Now rew can involve either definitions or equalities (either == or =).
  1652 
  1653 * case_tac provided for compatibility with HOL
  1654     (like the old excluded_middle_tac, but with subgoals swapped)
  1655 
  1656 
  1657 *** Internal programming interfaces ***
  1658 
  1659 * Pure: several new basic modules made available for general use, see
  1660 also src/Pure/README;
  1661 
  1662 * improved the theory data mechanism to support encapsulation (data
  1663 kind name replaced by private Object.kind, acting as authorization
  1664 key); new type-safe user interface via functor TheoryDataFun; generic
  1665 print_data function becomes basically useless;
  1666 
  1667 * removed global_names compatibility flag -- all theory declarations
  1668 are qualified by default;
  1669 
  1670 * module Pure/Syntax now offers quote / antiquote translation
  1671 functions (useful for Hoare logic etc. with implicit dependencies);
  1672 see HOL/ex/Antiquote for an example use;
  1673 
  1674 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1675 cterm -> thm;
  1676 
  1677 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1678 subgoal;
  1679 
  1680 * Display.print_goals function moved to Locale.print_goals;
  1681 
  1682 * standard print function for goals supports current_goals_markers
  1683 variable for marking begin of proof, end of proof, start of goal; the
  1684 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1685 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1686 for example;
  1687 
  1688 
  1689 
  1690 New in Isabelle98 (January 1998)
  1691 --------------------------------
  1692 
  1693 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1694 
  1695 * changed lexical syntax of terms / types: dots made part of long
  1696 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1697 
  1698 * simpset (and claset) reference variable replaced by functions
  1699 simpset / simpset_ref;
  1700 
  1701 * no longer supports theory aliases (via merge) and non-trivial
  1702 implicit merge of thms' signatures;
  1703 
  1704 * most internal names of constants changed due to qualified names;
  1705 
  1706 * changed Pure/Sequence interface (see Pure/seq.ML);
  1707 
  1708 
  1709 *** General Changes ***
  1710 
  1711 * hierachically structured name spaces (for consts, types, axms, thms
  1712 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1713 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1714 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1715 long_names for fully qualified output names; NOTE: ML programs
  1716 (special tactics, packages etc.) referring to internal names may have
  1717 to be adapted to cope with fully qualified names; in case of severe
  1718 backward campatibility problems try setting 'global_names' at compile
  1719 time to have enrything declared within a flat name space; one may also
  1720 fine tune name declarations in theories via the 'global' and 'local'
  1721 section;
  1722 
  1723 * reimplemented the implicit simpset and claset using the new anytype
  1724 data filed in signatures; references simpset:simpset ref etc. are
  1725 replaced by functions simpset:unit->simpset and
  1726 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1727 to patch your ML files accordingly;
  1728 
  1729 * HTML output now includes theory graph data for display with Java
  1730 applet or isatool browser; data generated automatically via isatool
  1731 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1732 
  1733 * defs may now be conditional; improved rewrite_goals_tac to handle
  1734 conditional equations;
  1735 
  1736 * defs now admits additional type arguments, using TYPE('a) syntax;
  1737 
  1738 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1739 creates a new theory node; implicit merge of thms' signatures is
  1740 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1741 transfer:theory->thm->thm in (rare) cases;
  1742 
  1743 * improved handling of draft signatures / theories; draft thms (and
  1744 ctyps, cterms) are automatically promoted to real ones;
  1745 
  1746 * slightly changed interfaces for oracles: admit many per theory, named
  1747 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1748 
  1749 * print_goals: optional output of const types (set show_consts and
  1750 show_types);
  1751 
  1752 * improved output of warnings (###) and errors (***);
  1753 
  1754 * subgoal_tac displays a warning if the new subgoal has type variables;
  1755 
  1756 * removed old README and Makefiles;
  1757 
  1758 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1759 
  1760 * removed obsolete init_pps and init_database;
  1761 
  1762 * deleted the obsolete tactical STATE, which was declared by
  1763     fun STATE tacfun st = tacfun st st;
  1764 
  1765 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1766 (which abbreviates $HOME);
  1767 
  1768 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1769 use isatool fixseq to adapt your ML programs (this works for fully
  1770 qualified references to the Sequence structure only!);
  1771 
  1772 * use_thy no longer requires writable current directory; it always
  1773 reloads .ML *and* .thy file, if either one is out of date;
  1774 
  1775 
  1776 *** Classical Reasoner ***
  1777 
  1778 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1779 tactics that use classical reasoning to simplify a subgoal without
  1780 splitting it into several subgoals;
  1781 
  1782 * Safe_tac: like safe_tac but uses the default claset;
  1783 
  1784 
  1785 *** Simplifier ***
  1786 
  1787 * added simplification meta rules:
  1788     (asm_)(full_)simplify: simpset -> thm -> thm;
  1789 
  1790 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1791 logics (again);
  1792 
  1793 * added prems argument to simplification procedures;
  1794 
  1795 * HOL, FOL, ZF: added infix function `addsplits':
  1796   instead of `<simpset> setloop (split_tac <thms>)'
  1797   you can simply write `<simpset> addsplits <thms>'
  1798 
  1799 
  1800 *** Syntax ***
  1801 
  1802 * TYPE('a) syntax for type reflection terms;
  1803 
  1804 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1805 
  1806 * pretty printer: changed order of mixfix annotation preference (again!);
  1807 
  1808 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1809 
  1810 
  1811 *** HOL ***
  1812 
  1813 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1814   with `addloop' of the simplifier to faciliate case splitting in premises.
  1815 
  1816 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1817 
  1818 * HOL/Auth: new protocol proofs including some for the Internet
  1819   protocol TLS;
  1820 
  1821 * HOL/Map: new theory of `maps' a la VDM;
  1822 
  1823 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1824 cancelling out common nat summands from =, <, <= (in)equalities, or
  1825 differences; simplification procedures nat_cancel_factor for
  1826 cancelling common factor from =, <, <= (in)equalities over natural
  1827 sums; nat_cancel contains both kinds of procedures, it is installed by
  1828 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1829 
  1830 * HOL/simplifier: terms of the form
  1831   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1832   are rewritten to
  1833   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1834   and those of the form
  1835   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1836   are rewritten to
  1837   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1838 
  1839 * HOL/datatype
  1840   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1841 
  1842   P(t_case f1 ... fn x) =
  1843      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1844         ...
  1845        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1846      )
  1847 
  1848   and a theorem `split_t_case_asm' of the form
  1849 
  1850   P(t_case f1 ... fn x) =
  1851     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1852         ...
  1853        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1854      )
  1855   which can be added to a simpset via `addsplits'. The existing theorems
  1856   expand_list_case and expand_option_case have been renamed to
  1857   split_list_case and split_option_case.
  1858 
  1859 * HOL/Arithmetic:
  1860   - `pred n' is automatically converted to `n-1'.
  1861     Users are strongly encouraged not to use `pred' any longer,
  1862     because it will disappear altogether at some point.
  1863   - Users are strongly encouraged to write "0 < n" rather than
  1864     "n ~= 0". Theorems and proof tools have been modified towards this
  1865     `standard'.
  1866 
  1867 * HOL/Lists:
  1868   the function "set_of_list" has been renamed "set" (and its theorems too);
  1869   the function "nth" now takes its arguments in the reverse order and
  1870   has acquired the infix notation "!" as in "xs!n".
  1871 
  1872 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1873 
  1874 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1875   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1876 
  1877 * HOL/record: extensible records with schematic structural subtyping
  1878 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1879 still lacks various theorems and concrete record syntax;
  1880 
  1881 
  1882 *** HOLCF ***
  1883 
  1884 * removed "axioms" and "generated by" sections;
  1885 
  1886 * replaced "ops" section by extended "consts" section, which is capable of
  1887   handling the continuous function space "->" directly;
  1888 
  1889 * domain package:
  1890   . proves theorems immediately and stores them in the theory,
  1891   . creates hierachical name space,
  1892   . now uses normal mixfix annotations (instead of cinfix...),
  1893   . minor changes to some names and values (for consistency),
  1894   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1895   . separator between mutual domain defs: changed "," to "and",
  1896   . improved handling of sort constraints;  now they have to
  1897     appear on the left-hand side of the equations only;
  1898 
  1899 * fixed LAM <x,y,zs>.b syntax;
  1900 
  1901 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1902 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1903 
  1904 
  1905 *** FOL and ZF ***
  1906 
  1907 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1908   with `addloop' of the simplifier to faciliate case splitting in premises.
  1909 
  1910 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1911 in HOL, they strip ALL and --> from proved theorems;
  1912 
  1913 
  1914 
  1915 New in Isabelle94-8 (May 1997)
  1916 ------------------------------
  1917 
  1918 *** General Changes ***
  1919 
  1920 * new utilities to build / run / maintain Isabelle etc. (in parts
  1921 still somewhat experimental); old Makefiles etc. still functional;
  1922 
  1923 * new 'Isabelle System Manual';
  1924 
  1925 * INSTALL text, together with ./configure and ./build scripts;
  1926 
  1927 * reimplemented type inference for greater efficiency, better error
  1928 messages and clean internal interface;
  1929 
  1930 * prlim command for dealing with lots of subgoals (an easier way of
  1931 setting goals_limit);
  1932 
  1933 
  1934 *** Syntax ***
  1935 
  1936 * supports alternative (named) syntax tables (parser and pretty
  1937 printer); internal interface is provided by add_modesyntax(_i);
  1938 
  1939 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1940 be used in conjunction with the Isabelle symbol font; uses the
  1941 "symbols" syntax table;
  1942 
  1943 * added token_translation interface (may translate name tokens in
  1944 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1945 the current print_mode); IMPORTANT: user print translation functions
  1946 are responsible for marking newly introduced bounds
  1947 (Syntax.mark_boundT);
  1948 
  1949 * token translations for modes "xterm" and "xterm_color" that display
  1950 names in bold, underline etc. or colors (which requires a color
  1951 version of xterm);
  1952 
  1953 * infixes may now be declared with names independent of their syntax;
  1954 
  1955 * added typed_print_translation (like print_translation, but may
  1956 access type of constant);
  1957 
  1958 
  1959 *** Classical Reasoner ***
  1960 
  1961 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1962 some limitations.  Blast_tac...
  1963   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1964   + ignores elimination rules that don't have the correct format
  1965         (the conclusion MUST be a formula variable)
  1966   + ignores types, which can make HOL proofs fail
  1967   + rules must not require higher-order unification, e.g. apply_type in ZF
  1968     [message "Function Var's argument not a bound variable" relates to this]
  1969   + its proof strategy is more general but can actually be slower
  1970 
  1971 * substitution with equality assumptions no longer permutes other
  1972 assumptions;
  1973 
  1974 * minor changes in semantics of addafter (now called addaltern); renamed
  1975 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1976 (and access functions for it);
  1977 
  1978 * improved combination of classical reasoner and simplifier:
  1979   + functions for handling clasimpsets
  1980   + improvement of addss: now the simplifier is called _after_ the
  1981     safe steps.
  1982   + safe variant of addss called addSss: uses safe simplifications
  1983     _during_ the safe steps. It is more complete as it allows multiple
  1984     instantiations of unknowns (e.g. with slow_tac).
  1985 
  1986 *** Simplifier ***
  1987 
  1988 * added interface for simplification procedures (functions that
  1989 produce *proven* rewrite rules on the fly, depending on current
  1990 redex);
  1991 
  1992 * ordering on terms as parameter (used for ordered rewriting);
  1993 
  1994 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1995 
  1996 * the solver is now split into a safe and an unsafe part.
  1997 This should be invisible for the normal user, except that the
  1998 functions setsolver and addsolver have been renamed to setSolver and
  1999 addSolver; added safe_asm_full_simp_tac;
  2000 
  2001 
  2002 *** HOL ***
  2003 
  2004 * a generic induction tactic `induct_tac' which works for all datatypes and
  2005 also for type `nat';
  2006 
  2007 * a generic case distinction tactic `exhaust_tac' which works for all
  2008 datatypes and also for type `nat';
  2009 
  2010 * each datatype comes with a function `size';
  2011 
  2012 * patterns in case expressions allow tuple patterns as arguments to
  2013 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2014 
  2015 * primrec now also works with type nat;
  2016 
  2017 * recdef: a new declaration form, allows general recursive functions to be
  2018 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2019 
  2020 * the constant for negation has been renamed from "not" to "Not" to
  2021 harmonize with FOL, ZF, LK, etc.;
  2022 
  2023 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2024 infinite lists;
  2025 
  2026 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2027 
  2028 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2029 problems in commutative rings, using axiomatic type classes for + and *;
  2030 
  2031 * more examples in HOL/MiniML and HOL/Auth;
  2032 
  2033 * more default rewrite rules for quantifiers, union/intersection;
  2034 
  2035 * a new constant `arbitrary == @x.False';
  2036 
  2037 * HOLCF/IOA replaces old HOL/IOA;
  2038 
  2039 * HOLCF changes: derived all rules and arities
  2040   + axiomatic type classes instead of classes
  2041   + typedef instead of faking type definitions
  2042   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2043   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2044   + eliminated the types void, one, tr
  2045   + use unit lift and bool lift (with translations) instead of one and tr
  2046   + eliminated blift from Lift3.thy (use Def instead of blift)
  2047   all eliminated rules are derived as theorems --> no visible changes ;
  2048 
  2049 
  2050 *** ZF ***
  2051 
  2052 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2053 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2054 as ZF_cs addSIs [equalityI];
  2055 
  2056 
  2057 
  2058 New in Isabelle94-7 (November 96)
  2059 ---------------------------------
  2060 
  2061 * allowing negative levels (as offsets) in prlev and choplev;
  2062 
  2063 * super-linear speedup for large simplifications;
  2064 
  2065 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2066 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2067 FAIL); can suppress it using the command Delsimps (ex_simps @
  2068 all_simps); De Morgan laws are also now included, by default;
  2069 
  2070 * improved printing of ==>  :  ~:
  2071 
  2072 * new object-logic "Sequents" adds linear logic, while replacing LK
  2073 and Modal (thanks to Sara Kalvala);
  2074 
  2075 * HOL/Auth: correctness proofs for authentication protocols;
  2076 
  2077 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2078 examples on HOL/Auth);
  2079 
  2080 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2081 the rewriter and classical reasoner simultaneously;
  2082 
  2083 * function uresult no longer returns theorems in "standard" format;
  2084 regain previous version by: val uresult = standard o uresult;
  2085 
  2086 
  2087 
  2088 New in Isabelle94-6
  2089 -------------------
  2090 
  2091 * oracles -- these establish an interface between Isabelle and trusted
  2092 external reasoners, which may deliver results as theorems;
  2093 
  2094 * proof objects (in particular record all uses of oracles);
  2095 
  2096 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2097 
  2098 * "constdefs" section in theory files;
  2099 
  2100 * "primrec" section (HOL) no longer requires names;
  2101 
  2102 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2103 
  2104 
  2105 
  2106 New in Isabelle94-5
  2107 -------------------
  2108 
  2109 * reduced space requirements;
  2110 
  2111 * automatic HTML generation from theories;
  2112 
  2113 * theory files no longer require "..." (quotes) around most types;
  2114 
  2115 * new examples, including two proofs of the Church-Rosser theorem;
  2116 
  2117 * non-curried (1994) version of HOL is no longer distributed;
  2118 
  2119 
  2120 
  2121 New in Isabelle94-4
  2122 -------------------
  2123 
  2124 * greatly reduced space requirements;
  2125 
  2126 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2127 
  2128 * searchable theorem database (see the section "Retrieving theorems" on
  2129 page 8 of the Reference Manual);
  2130 
  2131 * new examples, including Grabczewski's monumental case study of the
  2132 Axiom of Choice;
  2133 
  2134 * The previous version of HOL renamed to Old_HOL;
  2135 
  2136 * The new version of HOL (previously called CHOL) uses a curried syntax
  2137 for functions.  Application looks like f a b instead of f(a,b);
  2138 
  2139 * Mutually recursive inductive definitions finally work in HOL;
  2140 
  2141 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2142 translates to the operator "split";
  2143 
  2144 
  2145 
  2146 New in Isabelle94-3
  2147 -------------------
  2148 
  2149 * new infix operator, addss, allowing the classical reasoner to
  2150 perform simplification at each step of its search.  Example:
  2151         fast_tac (cs addss ss)
  2152 
  2153 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2154 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2155 look like (a,b) instead of <a,b>;
  2156 
  2157 * PLEASE NOTE: CHOL will eventually replace HOL!
  2158 
  2159 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2160 It translates to the operator "split".  A new theory of integers is available;
  2161 
  2162 * In ZF, integer numerals now denote two's-complement binary integers.
  2163 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2164 
  2165 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2166 of the Axiom of Choice;
  2167 
  2168 
  2169 
  2170 New in Isabelle94-2
  2171 -------------------
  2172 
  2173 * Significantly faster resolution;
  2174 
  2175 * the different sections in a .thy file can now be mixed and repeated
  2176 freely;
  2177 
  2178 * Database of theorems for FOL, HOL and ZF.  New
  2179 commands including qed, qed_goal and bind_thm store theorems in the database.
  2180 
  2181 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2182 a given theory (thms_of), or find out what theory a theorem was proved in
  2183 (theory_of_thm);
  2184 
  2185 * Bugs fixed in the inductive definition and datatype packages;
  2186 
  2187 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2188 and HOL_dup_cs obsolete;
  2189 
  2190 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2191 have been removed;
  2192 
  2193 * Simpler definition of function space in ZF;
  2194 
  2195 * new results about cardinal and ordinal arithmetic in ZF;
  2196 
  2197 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2198 types;
  2199 
  2200 
  2201 $Id$