NEWS
author paulson
Fri Jan 25 15:42:59 2002 +0100 (2002-01-25)
changeset 12850 d3c16021e999
parent 12837 74ce01905e57
child 12853 de505273c971
permissions -rw-r--r--
ZF
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2002 (January 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 Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
    31 
    32 * isatool latex no longer depends on changed TEXINPUTS, instead
    33 isatool document copies the Isabelle style files to the target
    34 location;
    35 
    36 
    37 *** Isar ***
    38 
    39 * Pure/Provers: improved proof by cases and induction;
    40   - 'case' command admits impromptu naming of parameters (such as
    41     "case (Suc n)");
    42   - 'induct' method divinates rule instantiation from the inductive
    43     claim; no longer requires excessive ?P bindings for proper
    44     instantiation of cases;
    45   - 'induct' method properly enumerates all possibilities of set/type
    46     rules; as a consequence facts may be also passed through *type*
    47     rules without further ado;
    48   - 'induct' method now derives symbolic cases from the *rulified*
    49     rule (before it used to rulify cases stemming from the internal
    50     atomized version); this means that the context of a non-atomic
    51     statement becomes is included in the hypothesis, avoiding the
    52     slightly cumbersome show "PROP ?case" form;
    53   - 'induct' may now use elim-style induction rules without chaining
    54     facts, using ``missing'' premises from the goal state; this allows
    55     rules stemming from inductive sets to be applied in unstructured
    56     scripts, while still benefitting from proper handling of non-atomic
    57     statements; NB: major inductive premises need to be put first, all
    58     the rest of the goal is passed through the induction;
    59   - 'induct' proper support for mutual induction involving non-atomic
    60     rule statements (uses the new concept of simultaneous goals, see
    61     below);
    62   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    63   - undeclared rule case names default to numbers 1, 2, 3, ...;
    64   - added 'print_induct_rules' (covered by help item in recent Proof
    65     General versions);
    66   - moved induct/cases attributes to Pure, methods to Provers;
    67   - generic method setup instantiated for FOL and HOL;
    68 
    69 * Pure: support multiple simultaneous goal statements, for example
    70 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    71 meta-level mechanism, this acts as if several individual goals had
    72 been stated separately; in particular common proof methods need to be
    73 repeated in order to cover all claims; note that a single elimination
    74 step is *not* sufficient to establish the two conjunctions, so this
    75 fails:
    76 
    77   assume "A & B" then have A and B ..   (*".." fails*)
    78 
    79 better use "obtain" in situations as above; alternative refer to
    80 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    81 
    82 * Pure: proper integration with ``locales''; unlike the original
    83 version by Florian Kammüller, Isar locales package high-level proof
    84 contexts rather than raw logical ones (e.g. we admit to include
    85 attributes everywhere); operations on locales include merge and
    86 rename; e.g. see HOL/ex/Locales.thy;
    87 
    88 * Pure: the following commands have been ``localized'', supporting a
    89 target locale specification "(in name)": 'lemma', 'theorem',
    90 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
    91 stored both within the locale and at the theory level (exported and
    92 qualified by the locale name);
    93 
    94 * Pure: theory goals now support ad-hoc contexts, which are discharged
    95 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    96 coincides with that of a locale body;
    97 
    98 * Pure: renamed "antecedent" case to "rule_context";
    99 
   100 * Pure: added 'corollary' command;
   101 
   102 * Pure: fixed 'token_translation' command;
   103 
   104 * Pure: removed obsolete 'exported' attribute;
   105 
   106 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   107 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   108 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   109 
   110 * Pure: method 'atomize' presents local goal premises as object-level
   111 statements (atomic meta-level propositions); setup controlled via
   112 rewrite rules declarations of 'atomize' attribute; example
   113 application: 'induct' method with proper rule statements in improper
   114 proof *scripts*;
   115 
   116 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   117 now consider the syntactic context of assumptions, giving a better
   118 chance to get type-inference of the arguments right (this is
   119 especially important for locales);
   120 
   121 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   122 mode;
   123 
   124 * Pure/obtain: the formal conclusion "thesis", being marked as
   125 ``internal'', may no longer be reference directly in the text;
   126 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   127 situations;
   128 
   129 * Pure: generic 'sym' attribute which declares a rule both as pure
   130 'elim?' and for the 'symmetric' operation;
   131 
   132 * Pure/Provers/classical: simplified integration with pure rule
   133 attributes and methods; the classical "intro?/elim?/dest?"
   134 declarations coincide with the pure ones; the "rule" method no longer
   135 includes classically swapped intros; "intro" and "elim" methods no
   136 longer pick rules from the context; also got rid of ML declarations
   137 AddXIs/AddXEs/AddXDs; all of this has some potential for
   138 INCOMPATIBILITY;
   139 
   140 * Provers/classical: attribute 'swapped' produces classical inversions
   141 of introduction rules;
   142 
   143 * Provers/simplifier: 'simplified' attribute may refer to explicit
   144 rules instead of full simplifier context; 'iff' attribute handles
   145 conditional rules;
   146 
   147 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   148 
   149 * HOL: 'recdef' now fails on unfinished automated proofs, use
   150 "(permissive)" option to recover old behavior;
   151 
   152 * HOL: 'inductive' no longer features separate (collective) attributes
   153 for 'intros' (was found too confusing);
   154 
   155 * HOL: properly declared induction rules less_induct and
   156 wf_induct_rule;
   157 
   158 
   159 *** HOL ***
   160 
   161 * HOL: moved over to sane numeral syntax; the new policy is as
   162 follows:
   163 
   164   - 0 and 1 are polymorphic constants, which are defined on any
   165   numeric type (nat, int, real etc.);
   166 
   167   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   168   binary representation internally;
   169 
   170   - type nat has special constructor Suc, and generally prefers Suc 0
   171   over 1::nat and Suc (Suc 0) over 2::nat;
   172 
   173 This change may cause significant problems of INCOMPATIBILITY; here
   174 are some hints on converting existing sources:
   175 
   176   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   177   entities, so expressions involving "-" (unary or binary minus) need
   178   to be spaced properly;
   179 
   180   - existing occurrences of "1" may need to be constraint "1::nat" or
   181   even replaced by Suc 0; similar for old "2";
   182 
   183   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   184 
   185   - remove all special provisions on numerals in proofs;
   186 
   187 * HOL: simp rules nat_number_of expand numerals on nat to Suc/0
   188 representation (depends on bin_arith_simps in the default context);
   189 
   190 * HOL: symbolic syntax for x^2 (numeral 2);
   191 
   192 * HOL: the class of all HOL types is now called "type" rather than
   193 "term"; INCOMPATIBILITY, need to adapt references to this type class
   194 in axclass/classes, instance/arities, and (usually rare) occurrences
   195 in typings (of consts etc.); internally the class is called
   196 "HOL.type", ML programs should refer to HOLogic.typeS;
   197 
   198 * HOL/record package improvements:
   199   - new derived operations "fields" to build a partial record section,
   200     "extend" to promote a fixed record to a record scheme, and
   201     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   202     declared as simp by default;
   203   - shared operations ("more", "fields", etc.) now need to be always
   204     qualified) --- potential INCOMPATIBILITY;
   205   - removed "make_scheme" operations (use "make" with "extend") --
   206     INCOMPATIBILITY;
   207   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   208   - provides cases/induct rules for use with corresponding Isar
   209     methods (for concrete records, record schemes, concrete more
   210     parts, and schematic more parts -- in that order);
   211   - internal definitions directly based on a light-weight abstract
   212     theory of product types over typedef rather than datatype;
   213 
   214 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   215 
   216 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   217 (beware of argument permutation!);
   218 
   219 * HOL: linorder_less_split superseded by linorder_cases;
   220 
   221 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   222 to peripheral theory "Hilbert_Choice";
   223 
   224 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   225 in this (rare) case use:
   226 
   227   delSWrapper "split_all_tac"
   228   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   229 
   230 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   231 MAY FAIL;
   232 
   233 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   234 Isabelle's type classes, ^ on functions and relations has too general
   235 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   236 necessary to attach explicit type constraints;
   237 
   238 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   239 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   240 (eg "compI" -> "rel_compI").
   241 
   242 * HOL: syntax translations now work properly with numerals and records
   243 expressions;
   244 
   245 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   246 of "lam" -- INCOMPATIBILITY;
   247 
   248 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   249 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   250 renamed "Product_Type.unit";
   251 
   252 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   253 
   254 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   255 Florian Kammüller);
   256 
   257 * HOL/IMP: updated and converted to new-style theory format; several
   258 parts turned into readable document, with proper Isar proof texts and
   259 some explanations (by Gerwin Klein);
   260 
   261 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   262 
   263 * HOL-Hyperreal is now a logic image;
   264 
   265 
   266 *** HOLCF ***
   267 
   268 * Isar: consts/constdefs supports mixfix syntax for continuous
   269 operations;
   270 
   271 * Isar: domain package adapted to new-style theory format, e.g. see
   272 HOLCF/ex/Dnat.thy;
   273 
   274 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   275 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   276 lift.induct_tac, always use UU instead of Undef;
   277 
   278 * HOLCF/IMP: updated and converted to new-style theory;
   279 
   280 
   281 *** ZF ***
   282 
   283 * Isar: proper integration of logic-specific tools and packages,
   284 including theory commands '(co)inductive', '(co)datatype',
   285 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   286 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   287 
   288 * theory Main no longer includes AC; for the Axiom of Choice, base
   289 your theory on Main_ZFC;
   290 
   291 * the integer library now covers quotients and remainders, with many
   292 laws relating division to addition, multiplication, etc.;
   293 
   294 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   295 typeless version of the formalism;
   296 
   297 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory format;
   298 
   299 * ZF/Induct: new directory for examples of inductive definitions,
   300 including theory Multiset for multiset orderings; converted to
   301 new-style theory format;
   302 
   303 * Many new theorems about lists, ordinals, etc.;
   304 
   305 
   306 *** General ***
   307 
   308 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   309 variable proof controls level of detail: 0 = no proofs (only oracle
   310 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   311 also ref manual for further ML interfaces;
   312 
   313 * Pure/axclass: removed obsolete ML interface
   314 goal_subclass/goal_arity;
   315 
   316 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   317 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   318 separate tokens, so expressions involving minus need to be spaced
   319 properly;
   320 
   321 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   322 rather than "infixl" or "infixr";
   323 
   324 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   325 sort constraint specifications in type inference; e.g. "x::_::foo"
   326 ensures that the type of "x" is of sort "foo" (but not necessarily a
   327 type variable);
   328 
   329 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   330 control output of nested => (types); the default behavior is
   331 "type_brackets";
   332 
   333 * Pure/syntax: builtin parse translation for "_constify" turns valued
   334 tokens into AST constants;
   335 
   336 * Pure/syntax: prefer later declarations of translations and print
   337 translation functions; potential INCOMPATIBILITY: need to reverse
   338 multiple declarations for same syntax element constant;
   339 
   340 * Pure/show_hyps reset by default (in accordance to existing Isar
   341 practice);
   342 
   343 * Provers/classical: renamed addaltern to addafter, addSaltern to
   344 addSafter;
   345 
   346 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   347 as well;
   348 
   349 * system: tested support for MacOS X; should be able to get Isabelle +
   350 Proof General to work in a plain Terminal after installing Poly/ML
   351 (e.g. from the Isabelle distribution area) and GNU bash alone
   352 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   353 support requires further installations, e.g. from
   354 http://fink.sourceforge.net/);
   355 
   356 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   357 
   358 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   359 of 40 MB), cf. ML_OPTIONS;
   360 
   361 * system: Proof General keywords specification is now part of the
   362 Isabelle distribution (see etc/isar-keywords.el);
   363 
   364 * system: support for persistent Proof General sessions (refrain from
   365 outdating all loaded theories on startup); user may create writable
   366 logic images like this: ``isabelle -q HOL Test'';
   367 
   368 * system: smart selection of Isabelle process versus Isabelle
   369 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   370 run both "isabelle" and "Isabelle" even if file names are badly
   371 damaged (executable inspects the case of the first letter of its own
   372 name); added separate "isabelle-process" and "isabelle-interface";
   373 
   374 * system: refrain from any attempt at filtering input streams; no
   375 longer support ``8bit'' encoding of old isabelle font, instead proper
   376 iso-latin characters may now be used; the related isatools
   377 "symbolinput" and "nonascii" have disappeared as well;
   378 
   379 * system: removed old "xterm" interface (the print modes "xterm" and
   380 "xterm_color" are still available for direct use in a suitable
   381 terminal);
   382 
   383 
   384 
   385 New in Isabelle99-2 (February 2001)
   386 -----------------------------------
   387 
   388 *** Overview of INCOMPATIBILITIES ***
   389 
   390 * HOL: please note that theories in the Library and elsewhere often use the
   391 new-style (Isar) format; to refer to their theorems in an ML script you must
   392 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   393 
   394 * HOL: inductive package no longer splits induction rule aggressively,
   395 but only as far as specified by the introductions given; the old
   396 format may be recovered via ML function complete_split_rule or attribute
   397 'split_rule (complete)';
   398 
   399 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   400 gfp_Tarski to gfp_unfold;
   401 
   402 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   403 
   404 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   405 relation); infix "^^" has been renamed "``"; infix "``" has been
   406 renamed "`"; "univalent" has been renamed "single_valued";
   407 
   408 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   409 operation;
   410 
   411 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   412 
   413 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   414 
   415 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   416 consequence, it is no longer monotonic wrt. the local goal context
   417 (which is now passed through the inductive cases);
   418 
   419 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   420 \<gg> to \<ggreater>;
   421 
   422 
   423 *** Document preparation ***
   424 
   425 * \isabellestyle{NAME} selects version of Isabelle output (currently
   426 available: are "it" for near math-mode best-style output, "sl" for
   427 slanted text style, and "tt" for plain type-writer; if no
   428 \isabellestyle command is given, output is according to slanted
   429 type-writer);
   430 
   431 * support sub/super scripts (for single symbols only), input syntax is
   432 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   433 
   434 * some more standard symbols; see Appendix A of the system manual for
   435 the complete list of symbols defined in isabellesym.sty;
   436 
   437 * improved isabelle style files; more abstract symbol implementation
   438 (should now use \isamath{...} and \isatext{...} in custom symbol
   439 definitions);
   440 
   441 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   442 state; Note that presentation of goal states does not conform to
   443 actual human-readable proof documents.  Please do not include goal
   444 states into document output unless you really know what you are doing!
   445 
   446 * proper indentation of antiquoted output with proportional LaTeX
   447 fonts;
   448 
   449 * no_document ML operator temporarily disables LaTeX document
   450 generation;
   451 
   452 * isatool unsymbolize tunes sources for plain ASCII communication;
   453 
   454 
   455 *** Isar ***
   456 
   457 * Pure: Isar now suffers initial goal statements to contain unbound
   458 schematic variables (this does not conform to actual readable proof
   459 documents, due to unpredictable outcome and non-compositional proof
   460 checking); users who know what they are doing may use schematic goals
   461 for Prolog-style synthesis of proven results;
   462 
   463 * Pure: assumption method (an implicit finishing) now handles actual
   464 rules as well;
   465 
   466 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   467 initial goal, declare "that" only as Pure intro (only for single
   468 steps); the "that" rule assumption may now be involved in implicit
   469 finishing, thus ".." becomes a feasible for trivial obtains;
   470 
   471 * Pure: default proof step now includes 'intro_classes'; thus trivial
   472 instance proofs may be performed by "..";
   473 
   474 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   475 statements as well;
   476 
   477 * Pure: more robust selection of calculational rules;
   478 
   479 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   480 rule (as well as the assumption rule);
   481 
   482 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   483 lemmas, using the graph browser tool;
   484 
   485 * Pure: predict failure of "show" in interactive mode;
   486 
   487 * Pure: 'thms_containing' now takes actual terms as arguments;
   488 
   489 * HOL: improved method 'induct' --- now handles non-atomic goals
   490 (potential INCOMPATIBILITY); tuned error handling;
   491 
   492 * HOL: cases and induct rules now provide explicit hints about the
   493 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   494 any remaining facts are inserted into the goal verbatim;
   495 
   496 * HOL: local contexts (aka cases) may now contain term bindings as
   497 well; the 'cases' and 'induct' methods new provide a ?case binding for
   498 the result to be shown in each case;
   499 
   500 * HOL: added 'recdef_tc' command;
   501 
   502 * isatool convert assists in eliminating legacy ML scripts;
   503 
   504 
   505 *** HOL ***
   506 
   507 * HOL/Library: a collection of generic theories to be used together
   508 with main HOL; the theory loader path already includes this directory
   509 by default; the following existing theories have been moved here:
   510 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   511 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   512 
   513 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   514 modelling and verification task performed in Isabelle/HOL +
   515 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   516 
   517 * HOL/Algebra: special summation operator SUM no longer exists, it has
   518 been replaced by setsum; infix 'assoc' now has priority 50 (like
   519 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   520 'domain', this makes the theory consistent with mathematical
   521 literature;
   522 
   523 * HOL basics: added overloaded operations "inverse" and "divide"
   524 (infix "/"), syntax for generic "abs" operation, generic summation
   525 operator \<Sum>;
   526 
   527 * HOL/typedef: simplified package, provide more useful rules (see also
   528 HOL/subset.thy);
   529 
   530 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   531 now expressed as a proper nested rule (old-style tactic scripts may
   532 require atomize_strip_tac to cope with non-atomic premises);
   533 
   534 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   535 to "split_conv" (old name still available for compatibility);
   536 
   537 * HOL: improved concrete syntax for strings (e.g. allows translation
   538 rules with string literals);
   539 
   540 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   541  and Fleuriot's mechanization of analysis, including the transcendental
   542  functions for the reals;
   543 
   544 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   545 
   546 
   547 *** CTT ***
   548 
   549 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   550 "lam" is displayed as TWO lambda-symbols
   551 
   552 * CTT: theory Main now available, containing everything (that is, Bool
   553 and Arith);
   554 
   555 
   556 *** General ***
   557 
   558 * Pure: the Simplifier has been implemented properly as a derived rule
   559 outside of the actual kernel (at last!); the overall performance
   560 penalty in practical applications is about 50%, while reliability of
   561 the Isabelle inference kernel has been greatly improved;
   562 
   563 * print modes "brackets" and "no_brackets" control output of nested =>
   564 (types) and ==> (props); the default behaviour is "brackets";
   565 
   566 * Provers: fast_tac (and friends) now handle actual object-logic rules
   567 as assumptions as well;
   568 
   569 * system: support Poly/ML 4.0;
   570 
   571 * system: isatool install handles KDE version 1 or 2;
   572 
   573 
   574 
   575 New in Isabelle99-1 (October 2000)
   576 ----------------------------------
   577 
   578 *** Overview of INCOMPATIBILITIES ***
   579 
   580 * HOL: simplification of natural numbers is much changed; to partly
   581 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   582 issue the following ML commands:
   583 
   584   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   585   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   586 
   587 * HOL: simplification no longer dives into case-expressions; this is
   588 controlled by "t.weak_case_cong" for each datatype t;
   589 
   590 * HOL: nat_less_induct renamed to less_induct;
   591 
   592 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   593 fixsome to patch .thy and .ML sources automatically;
   594 
   595   select_equality  -> some_equality
   596   select_eq_Ex     -> some_eq_ex
   597   selectI2EX       -> someI2_ex
   598   selectI2         -> someI2
   599   selectI          -> someI
   600   select1_equality -> some1_equality
   601   Eps_sym_eq       -> some_sym_eq_trivial
   602   Eps_eq           -> some_eq_trivial
   603 
   604 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   605 
   606 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   607 instead);
   608 
   609 * HOL: the recursion equations generated by 'recdef' are now called
   610 f.simps instead of f.rules;
   611 
   612 * HOL: qed_spec_mp now also handles bounded ALL as well;
   613 
   614 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   615 sometimes be needed;
   616 
   617 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   618 
   619 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   620 
   621 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   622 product is now "<*>" instead of "Times"; the lexicographic product is
   623 now "<*lex*>" instead of "**";
   624 
   625 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   626 of main HOL, but was unused); better use HOL's datatype package;
   627 
   628 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   629 the old syntax may be recovered as follows:
   630 
   631   syntax (symbols)
   632     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   633       (infixl "\\<oplus>" 100)
   634 
   635 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   636 
   637 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   638 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   639 internally;
   640 
   641 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   642 changed from A/r to A//r;
   643 
   644 * ZF: new treatment of arithmetic (nat & int) may break some old
   645 proofs;
   646 
   647 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   648 rulify -> rule_format, elimify -> elim_format, ...);
   649 
   650 * Isar/Provers: intro/elim/dest attributes changed; renamed
   651 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   652 should have to change intro!! to intro? only); replaced "delrule" by
   653 "rule del";
   654 
   655 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   656 
   657 * Provers: strengthened force_tac by using new first_best_tac;
   658 
   659 * LaTeX document preparation: several changes of isabelle.sty (see
   660 lib/texinputs);
   661 
   662 
   663 *** Document preparation ***
   664 
   665 * formal comments (text blocks etc.) in new-style theories may now
   666 contain antiquotations of thm/prop/term/typ/text to be presented
   667 according to latex print mode; concrete syntax is like this:
   668 @{term[show_types] "f(x) = a + x"};
   669 
   670 * isatool mkdir provides easy setup of Isabelle session directories,
   671 including proper document sources;
   672 
   673 * generated LaTeX sources are now deleted after successful run
   674 (isatool document -c); may retain a copy somewhere else via -D option
   675 of isatool usedir;
   676 
   677 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   678 style files, achieving self-contained LaTeX sources and simplifying
   679 LaTeX debugging;
   680 
   681 * old-style theories now produce (crude) LaTeX output as well;
   682 
   683 * browser info session directories are now self-contained (may be put
   684 on WWW server seperately); improved graphs of nested sessions; removed
   685 graph for 'all sessions';
   686 
   687 * several improvements in isabelle style files; \isabellestyle{it}
   688 produces fake math mode output; \isamarkupheader is now \section by
   689 default; see lib/texinputs/isabelle.sty etc.;
   690 
   691 
   692 *** Isar ***
   693 
   694 * Isar/Pure: local results and corresponding term bindings are now
   695 subject to Hindley-Milner polymorphism (similar to ML); this
   696 accommodates incremental type-inference very nicely;
   697 
   698 * Isar/Pure: new derived language element 'obtain' supports
   699 generalized existence reasoning;
   700 
   701 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   702 support accumulation of results, without applying any rules yet;
   703 useful to collect intermediate results without explicit name
   704 references, and for use with transitivity rules with more than 2
   705 premises;
   706 
   707 * Isar/Pure: scalable support for case-analysis type proofs: new
   708 'case' language element refers to local contexts symbolically, as
   709 produced by certain proof methods; internally, case names are attached
   710 to theorems as "tags";
   711 
   712 * Isar/Pure: theory command 'hide' removes declarations from
   713 class/type/const name spaces;
   714 
   715 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   716 indicate potential overloading;
   717 
   718 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   719 
   720 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   721 "{a,b,c}" instead of {a,b,c};
   722 
   723 * Isar/Pure now provides its own version of intro/elim/dest
   724 attributes; useful for building new logics, but beware of confusion
   725 with the version in Provers/classical;
   726 
   727 * Isar/Pure: the local context of (non-atomic) goals is provided via
   728 case name 'antecedent';
   729 
   730 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   731 to the current context is now done automatically);
   732 
   733 * Isar/Pure: theory command 'method_setup' provides a simple interface
   734 for definining proof methods in ML;
   735 
   736 * Isar/Provers: intro/elim/dest attributes changed; renamed
   737 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   738 most cases, one should have to change intro!! to intro? only);
   739 replaced "delrule" by "rule del";
   740 
   741 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   742 'symmetric' attribute (the latter supercedes [RS sym]);
   743 
   744 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   745 method modifier); 'simp' method: 'only:' modifier removes loopers as
   746 well (including splits);
   747 
   748 * Isar/Provers: Simplifier and Classical methods now support all kind
   749 of modifiers used in the past, including 'cong', 'iff', etc.
   750 
   751 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   752 of Simplifier and Classical reasoner);
   753 
   754 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   755 now support named cases; major packages (inductive, datatype, primrec,
   756 recdef) support case names and properly name parameters;
   757 
   758 * Isar/HOL: new transitivity rules for substitution in inequalities --
   759 monotonicity conditions are extracted to be proven at end of
   760 calculations;
   761 
   762 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   763 method anyway;
   764 
   765 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   766 split_if split_if_asm; datatype package provides theorems foo.splits =
   767 foo.split foo.split_asm for each datatype;
   768 
   769 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   770 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   771 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   772 use "(cases (simplified))" method in proper proof texts);
   773 
   774 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   775 
   776 * Isar: names of theorems etc. may be natural numbers as well;
   777 
   778 * Isar: 'pr' command: optional arguments for goals_limit and
   779 ProofContext.prems_limit; no longer prints theory contexts, but only
   780 proof states;
   781 
   782 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   783 additional print modes to be specified; e.g. "pr(latex)" will print
   784 proof state according to the Isabelle LaTeX style;
   785 
   786 * Isar: improved support for emulating tactic scripts, including proof
   787 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   788 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   789 (for HOL datatypes);
   790 
   791 * Isar: simplified (more robust) goal selection of proof methods: 1st
   792 goal, all goals, or explicit goal specifier (tactic emulation); thus
   793 'proof method scripts' have to be in depth-first order;
   794 
   795 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   796 
   797 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   798 should instead use individual commands for printing items
   799 (print_commands, print_methods etc.);
   800 
   801 * Isar: added 'nothing' --- the empty list of theorems;
   802 
   803 
   804 *** HOL ***
   805 
   806 * HOL/MicroJava: formalization of a fragment of Java, together with a
   807 corresponding virtual machine and a specification of its bytecode
   808 verifier and a lightweight bytecode verifier, including proofs of
   809 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   810 Cornelia Pusch (see also the homepage of project Bali at
   811 http://isabelle.in.tum.de/Bali/);
   812 
   813 * HOL/Algebra: new theory of rings and univariate polynomials, by
   814 Clemens Ballarin;
   815 
   816 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   817 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   818 Rasmussen;
   819 
   820 * HOL/Lattice: fundamental concepts of lattice theory and order
   821 structures, including duals, properties of bounds versus algebraic
   822 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   823 Theorem for complete lattices etc.; may also serve as a demonstration
   824 for abstract algebraic reasoning using axiomatic type classes, and
   825 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   826 
   827 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   828 von Oheimb;
   829 
   830 * HOL/IMPP: extension of IMP with local variables and mutually
   831 recursive procedures, by David von Oheimb;
   832 
   833 * HOL/Lambda: converted into new-style theory and document;
   834 
   835 * HOL/ex/Multiquote: example of multiple nested quotations and
   836 anti-quotations -- basically a generalized version of de-Bruijn
   837 representation; very useful in avoiding lifting of operations;
   838 
   839 * HOL/record: added general record equality rule to simpset; fixed
   840 select-update simplification procedure to handle extended records as
   841 well; admit "r" as field name;
   842 
   843 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   844 other numeric types and also as the identity of groups, rings, etc.;
   845 
   846 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   847 Types nat and int belong to this axclass;
   848 
   849 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   850    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   851    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   852   two terms #m*u and #n*u are replaced by #(m+n)*u
   853     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   854   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   855     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   856 
   857 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   858 powerful prover for predicate logic but knows nothing of clasets; see
   859 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   860 
   861 * HOL: new version of "case_tac" subsumes both boolean case split and
   862 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   863 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   864 
   865 * HOL: simplification no longer dives into case-expressions: only the
   866 selector expression is simplified, but not the remaining arms; to
   867 enable full simplification of case-expressions for datatype t, you may
   868 remove t.weak_case_cong from the simpset, either globally (Delcongs
   869 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   870 
   871 * HOL/recdef: the recursion equations generated by 'recdef' for
   872 function 'f' are now called f.simps instead of f.rules; if all
   873 termination conditions are proved automatically, these simplification
   874 rules are added to the simpset, as in primrec; rules may be named
   875 individually as well, resulting in a separate list of theorems for
   876 each equation;
   877 
   878 * HOL/While is a new theory that provides a while-combinator. It
   879 permits the definition of tail-recursive functions without the
   880 provision of a termination measure. The latter is necessary once the
   881 invariant proof rule for while is applied.
   882 
   883 * HOL: new (overloaded) notation for the set of elements below/above
   884 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   885 
   886 * HOL: theorems impI, allI, ballI bound as "strip";
   887 
   888 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   889 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   890 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   891 
   892 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   893 
   894 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   895 main HOL, but was unused);
   896 
   897 * HOL: fewer consts declared as global (e.g. have to refer to
   898 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   899 
   900 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   901 in case of overlap with user translations (e.g. judgements over
   902 tuples); (note that the underlying logical represenation is still
   903 bogus);
   904 
   905 
   906 *** ZF ***
   907 
   908 * ZF: simplification automatically cancels common terms in arithmetic
   909 expressions over nat and int;
   910 
   911 * ZF: new treatment of nat to minimize type-checking: all operators
   912 coerce their operands to a natural number using the function natify,
   913 making the algebraic laws unconditional;
   914 
   915 * ZF: as above, for int: operators coerce their operands to an integer
   916 using the function intify;
   917 
   918 * ZF: the integer library now contains many of the usual laws for the
   919 orderings, including $<=, and monotonicity laws for $+ and $*;
   920 
   921 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   922 simplification;
   923 
   924 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   925 to the simplifier and classical reasoner simultaneously;
   926 
   927 
   928 *** General ***
   929 
   930 * Provers: blast_tac now handles actual object-logic rules as
   931 assumptions; note that auto_tac uses blast_tac internally as well;
   932 
   933 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   934 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   935 
   936 * Provers: delrules now handles destruct rules as well (no longer need
   937 explicit make_elim);
   938 
   939 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   940   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   941 use instead the strong form,
   942   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   943 in HOL, FOL and ZF the function cla_make_elim will create such rules
   944 from destruct-rules;
   945 
   946 * Provers: Simplifier.easy_setup provides a fast path to basic
   947 Simplifier setup for new object-logics;
   948 
   949 * Pure: AST translation rules no longer require constant head on LHS;
   950 
   951 * Pure: improved name spaces: ambiguous output is qualified; support
   952 for hiding of names;
   953 
   954 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   955 XSYMBOL_HOME; no longer need to do manual configuration in most
   956 situations;
   957 
   958 * system: compression of ML heaps images may now be controlled via -c
   959 option of isabelle and isatool usedir (currently only observed by
   960 Poly/ML);
   961 
   962 * system: isatool installfonts may handle X-Symbol fonts as well (very
   963 useful for remote X11);
   964 
   965 * system: provide TAGS file for Isabelle sources;
   966 
   967 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   968 order;
   969 
   970 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   971 timing flag supersedes proof_timing and Toplevel.trace;
   972 
   973 * ML: new combinators |>> and |>>> for incremental transformations
   974 with secondary results (e.g. certain theory extensions):
   975 
   976 * ML: PureThy.add_defs gets additional argument to indicate potential
   977 overloading (usually false);
   978 
   979 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   980 results;
   981 
   982 
   983 
   984 New in Isabelle99 (October 1999)
   985 --------------------------------
   986 
   987 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   988 
   989 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   990 are no longer simplified.  (This allows the simplifier to unfold recursive
   991 functional programs.)  To restore the old behaviour, declare
   992 
   993     Delcongs [if_weak_cong];
   994 
   995 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   996 complement;
   997 
   998 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   999 
  1000 * HOL/datatype: mutual_induct_tac no longer exists --
  1001   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1002 
  1003 * HOL/typedef: fixed type inference for representing set; type
  1004 arguments now have to occur explicitly on the rhs as type constraints;
  1005 
  1006 * ZF: The con_defs part of an inductive definition may no longer refer
  1007 to constants declared in the same theory;
  1008 
  1009 * HOL, ZF: the function mk_cases, generated by the inductive
  1010 definition package, has lost an argument.  To simplify its result, it
  1011 uses the default simpset instead of a supplied list of theorems.
  1012 
  1013 * HOL/List: the constructors of type list are now Nil and Cons;
  1014 
  1015 * Simplifier: the type of the infix ML functions
  1016         setSSolver addSSolver setSolver addSolver
  1017 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1018 for packaging solvers. A solver is created via
  1019         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1020 where the string argument is only a comment.
  1021 
  1022 
  1023 *** Proof tools ***
  1024 
  1025 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1026 decision procedure for linear arithmetic. Currently it is used for
  1027 types `nat', `int', and `real' in HOL (see below); it can, should and
  1028 will be instantiated for other types and logics as well.
  1029 
  1030 * The simplifier now accepts rewrite rules with flexible heads, eg
  1031      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1032   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1033   matching.
  1034 
  1035 
  1036 *** General ***
  1037 
  1038 * New Isabelle/Isar subsystem provides an alternative to traditional
  1039 tactical theorem proving; together with the ProofGeneral/isar user
  1040 interface it offers an interactive environment for developing human
  1041 readable proof documents (Isar == Intelligible semi-automated
  1042 reasoning); for further information see isatool doc isar-ref,
  1043 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1044 
  1045 * improved and simplified presentation of theories: better HTML markup
  1046 (including colors), graph views in several sizes; isatool usedir now
  1047 provides a proper interface for user theories (via -P option); actual
  1048 document preparation based on (PDF)LaTeX is available as well (for
  1049 new-style theories only); see isatool doc system for more information;
  1050 
  1051 * native support for Proof General, both for classic Isabelle and
  1052 Isabelle/Isar;
  1053 
  1054 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1055 using the graph browser tool;
  1056 
  1057 * Isabelle manuals now also available as PDF;
  1058 
  1059 * theory loader rewritten from scratch (may not be fully
  1060 bug-compatible); old loadpath variable has been replaced by show_path,
  1061 add_path, del_path, reset_path functions; new operations such as
  1062 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1063 isatool doc ref);
  1064 
  1065 * improved isatool install: option -k creates KDE application icon,
  1066 option -p DIR installs standalone binaries;
  1067 
  1068 * added ML_PLATFORM setting (useful for cross-platform installations);
  1069 more robust handling of platform specific ML images for SML/NJ;
  1070 
  1071 * the settings environment is now statically scoped, i.e. it is never
  1072 created again in sub-processes invoked from isabelle, isatool, or
  1073 Isabelle;
  1074 
  1075 * path element specification '~~' refers to '$ISABELLE_HOME';
  1076 
  1077 * in locales, the "assumes" and "defines" parts may be omitted if
  1078 empty;
  1079 
  1080 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1081 long arrows);
  1082 
  1083 * new print_mode "HTML";
  1084 
  1085 * new flag show_tags controls display of tags of theorems (which are
  1086 basically just comments that may be attached by some tools);
  1087 
  1088 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1089 mode and goal output format:
  1090 
  1091 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1092 244c244
  1093 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1094 ---
  1095 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1096 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1097 181c181
  1098 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1099 ---
  1100 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1101 
  1102 * function bind_thms stores lists of theorems (cf. bind_thm);
  1103 
  1104 * new shorthand tactics ftac, eatac, datac, fatac;
  1105 
  1106 * qed (and friends) now accept "" as result name; in that case the
  1107 theorem is not stored, but proper checks and presentation of the
  1108 result still apply;
  1109 
  1110 * theorem database now also indexes constants "Trueprop", "all",
  1111 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1112 
  1113 
  1114 *** HOL ***
  1115 
  1116 ** HOL arithmetic **
  1117 
  1118 * There are now decision procedures for linear arithmetic over nat and
  1119 int:
  1120 
  1121 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1122 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1123 are treated as atomic; subformulae not involving type `nat' or `int'
  1124 are ignored; quantified subformulae are ignored unless they are
  1125 positive universal or negative existential. The tactic has to be
  1126 invoked by hand and can be a little bit slow. In particular, the
  1127 running time is exponential in the number of occurrences of `min' and
  1128 `max', and `-' on `nat'.
  1129 
  1130 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1131 (negated) (in)equalities among the premises and the conclusion into
  1132 account (i.e. no compound formulae) and does not know about `min' and
  1133 `max', and `-' on `nat'. It is fast and is used automatically by the
  1134 simplifier.
  1135 
  1136 NB: At the moment, these decision procedures do not cope with mixed
  1137 nat/int formulae where the two parts interact, such as `m < n ==>
  1138 int(m) < int(n)'.
  1139 
  1140 * HOL/Numeral provides a generic theory of numerals (encoded
  1141 efficiently as bit strings); setup for types nat/int/real is in place;
  1142 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1143 int, existing theories and proof scripts may require a few additional
  1144 type constraints;
  1145 
  1146 * integer division and remainder can now be performed on constant
  1147 arguments;
  1148 
  1149 * many properties of integer multiplication, division and remainder
  1150 are now available;
  1151 
  1152 * An interface to the Stanford Validity Checker (SVC) is available through the
  1153 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1154 are proved automatically.  SVC must be installed separately, and its results
  1155 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1156 invocation of the underlying oracle).  For SVC see
  1157   http://verify.stanford.edu/SVC
  1158 
  1159 * IsaMakefile: the HOL-Real target now builds an actual image;
  1160 
  1161 
  1162 ** HOL misc **
  1163 
  1164 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1165 (in Isabelle/Isar) -- by Gertrud Bauer;
  1166 
  1167 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1168 analysis for assembly languages with subtypes;
  1169 
  1170 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1171 -- avoids syntactic ambiguities and treats state, transition, and
  1172 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1173 changed syntax and (many) tactics;
  1174 
  1175 * HOL/inductive: Now also handles more general introduction rules such
  1176   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1177   theorems are now maintained within the theory (maintained via the
  1178   "mono" attribute);
  1179 
  1180 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1181   (using function types) such as
  1182 
  1183   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1184 
  1185 * HOL/record: record_simproc (part of the default simpset) takes care
  1186 of selectors applied to updated records; record_split_tac is no longer
  1187 part of the default claset; update_defs may now be removed from the
  1188 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1189 
  1190   claset_ref () := claset() addSWrapper record_split_wrapper;
  1191   Delsimprocs [record_simproc]
  1192 
  1193 * HOL/typedef: fixed type inference for representing set; type
  1194 arguments now have to occur explicitly on the rhs as type constraints;
  1195 
  1196 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1197 names rather than an ML expression;
  1198 
  1199 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1200 supplied later.  Program schemes can be defined, such as
  1201     "While B C s = (if B s then While B C (C s) else s)"
  1202 where the well-founded relation can be chosen after B and C have been given.
  1203 
  1204 * HOL/List: the constructors of type list are now Nil and Cons;
  1205 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1206 course, ML tools referring to List.list.op # etc. have to be adapted;
  1207 
  1208 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1209 disabled by default; run isabelle with option -m HOL to get back to
  1210 the original Gordon/HOL-style output;
  1211 
  1212 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1213 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1214 
  1215 * HOL basic syntax simplified (more orthogonal): all variants of
  1216 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1217 Eps operator is provided as well: "SOME x. P[x]";
  1218 
  1219 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1220 
  1221 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1222 thus available for user theories;
  1223 
  1224 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1225 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1226 time;
  1227 
  1228 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1229 several times and then mp;
  1230 
  1231 
  1232 *** LK ***
  1233 
  1234 * the notation <<...>> is now available as a notation for sequences of
  1235 formulas;
  1236 
  1237 * the simplifier is now installed
  1238 
  1239 * the axiom system has been generalized (thanks to Soren Heilmann)
  1240 
  1241 * the classical reasoner now has a default rule database
  1242 
  1243 
  1244 *** ZF ***
  1245 
  1246 * new primrec section allows primitive recursive functions to be given
  1247 directly (as in HOL) over datatypes and the natural numbers;
  1248 
  1249 * new tactics induct_tac and exhaust_tac for induction (or case
  1250 analysis) over datatypes and the natural numbers;
  1251 
  1252 * the datatype declaration of type T now defines the recursor T_rec;
  1253 
  1254 * simplification automatically does freeness reasoning for datatype
  1255 constructors;
  1256 
  1257 * automatic type-inference, with AddTCs command to insert new
  1258 type-checking rules;
  1259 
  1260 * datatype introduction rules are now added as Safe Introduction rules
  1261 to the claset;
  1262 
  1263 * the syntax "if P then x else y" is now available in addition to
  1264 if(P,x,y);
  1265 
  1266 
  1267 *** Internal programming interfaces ***
  1268 
  1269 * tuned simplifier trace output; new flag debug_simp;
  1270 
  1271 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1272 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1273 
  1274 * AxClass.axclass_tac lost the theory argument;
  1275 
  1276 * tuned current_goals_markers semantics: begin / end goal avoids
  1277 printing empty lines;
  1278 
  1279 * removed prs and prs_fn hook, which was broken because it did not
  1280 include \n in its semantics, forcing writeln to add one
  1281 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1282 string -> unit if you really want to output text without newline;
  1283 
  1284 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1285 plain output, interface builders may have to enable 'isabelle_font'
  1286 mode to get Isabelle font glyphs as before;
  1287 
  1288 * refined token_translation interface; INCOMPATIBILITY: output length
  1289 now of type real instead of int;
  1290 
  1291 * theory loader actions may be traced via new ThyInfo.add_hook
  1292 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1293 your own database of information attached to *whole* theories -- as
  1294 opposed to intra-theory data slots offered via TheoryDataFun;
  1295 
  1296 * proper handling of dangling sort hypotheses (at last!);
  1297 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1298 extra sort hypotheses that can be witnessed from the type signature;
  1299 the force_strip_shyps flag is gone, any remaining shyps are simply
  1300 left in the theorem (with a warning issued by strip_shyps_warning);
  1301 
  1302 
  1303 
  1304 New in Isabelle98-1 (October 1998)
  1305 ----------------------------------
  1306 
  1307 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1308 
  1309 * several changes of automated proof tools;
  1310 
  1311 * HOL: major changes to the inductive and datatype packages, including
  1312 some minor incompatibilities of theory syntax;
  1313 
  1314 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1315 called `inj_on';
  1316 
  1317 * HOL: removed duplicate thms in Arith:
  1318   less_imp_add_less  should be replaced by  trans_less_add1
  1319   le_imp_add_le      should be replaced by  trans_le_add1
  1320 
  1321 * HOL: unary minus is now overloaded (new type constraints may be
  1322 required);
  1323 
  1324 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1325 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1326 now taken as an integer constant.
  1327 
  1328 * Pure: ML function 'theory_of' renamed to 'theory';
  1329 
  1330 
  1331 *** Proof tools ***
  1332 
  1333 * Simplifier:
  1334   1. Asm_full_simp_tac is now more aggressive.
  1335      1. It will sometimes reorient premises if that increases their power to
  1336         simplify.
  1337      2. It does no longer proceed strictly from left to right but may also
  1338         rotate premises to achieve further simplification.
  1339      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1340      old Asm_full_simp_tac in that it does not rotate premises.
  1341   2. The simplifier now knows a little bit about nat-arithmetic.
  1342 
  1343 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1344 allows for selected deletion of wrappers, by introduction of names for
  1345 wrapper functionals.  This implies that addbefore, addSbefore,
  1346 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1347 and that adding two tactics with the same name overwrites the first
  1348 one (emitting a warning).
  1349   type wrapper = (int -> tactic) -> (int -> tactic)
  1350   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1351   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1352   delWrapper, delSWrapper: claset *  string            -> claset
  1353   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1354 
  1355 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1356 semantics; addbefore now affects only the unsafe part of step_tac
  1357 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1358 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1359 by Force_tac;
  1360 
  1361 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1362 compWrapper; added safe wrapper (and access functions for it);
  1363 
  1364 * HOL/split_all_tac is now much faster and fails if there is nothing
  1365 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1366 and the names of the automatically generated variables have changed.
  1367 split_all_tac has moved within claset() from unsafe wrappers to safe
  1368 wrappers, which means that !!-bound variables are split much more
  1369 aggressively, and safe_tac and clarify_tac now split such variables.
  1370 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1371 Note: the same holds for record_split_tac, which does the job of
  1372 split_all_tac for record fields.
  1373 
  1374 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1375 permanently to the default simpset using Addsplits just like
  1376 Addsimps. They can be removed via Delsplits just like
  1377 Delsimps. Lower-case versions are also available.
  1378 
  1379 * HOL/Simplifier: The rule split_if is now part of the default
  1380 simpset. This means that the simplifier will eliminate all occurrences
  1381 of if-then-else in the conclusion of a goal. To prevent this, you can
  1382 either remove split_if completely from the default simpset by
  1383 `Delsplits [split_if]' or remove it in a specific call of the
  1384 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1385 other case splitting rules to/from the default simpset: every datatype
  1386 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1387 t is the name of the datatype).
  1388 
  1389 * Classical reasoner / Simplifier combination: new force_tac (and
  1390 derivatives Force_tac, force) combines rewriting and classical
  1391 reasoning (and whatever other tools) similarly to auto_tac, but is
  1392 aimed to solve the given subgoal completely.
  1393 
  1394 
  1395 *** General ***
  1396 
  1397 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1398 and `goalw': the theory is no longer needed as an explicit argument -
  1399 the current theory context is used; assumptions are no longer returned
  1400 at the ML-level unless one of them starts with ==> or !!; it is
  1401 recommended to convert to these new commands using isatool fixgoal
  1402 (backup your sources first!);
  1403 
  1404 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1405 the current theory context, and 'theory' to lookup stored theories;
  1406 
  1407 * new theory section 'locale' for declaring constants, assumptions and
  1408 definitions that have local scope;
  1409 
  1410 * new theory section 'nonterminals' for purely syntactic types;
  1411 
  1412 * new theory section 'setup' for generic ML setup functions
  1413 (e.g. package initialization);
  1414 
  1415 * the distribution now includes Isabelle icons: see
  1416 lib/logo/isabelle-{small,tiny}.xpm;
  1417 
  1418 * isatool install - install binaries with absolute references to
  1419 ISABELLE_HOME/bin;
  1420 
  1421 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1422 
  1423 * print mode 'emacs' reserved for Isamode;
  1424 
  1425 * support multiple print (ast) translations per constant name;
  1426 
  1427 * theorems involving oracles are now printed with a suffixed [!];
  1428 
  1429 
  1430 *** HOL ***
  1431 
  1432 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1433 
  1434 * HOL/inductive package reorganized and improved: now supports mutual
  1435 definitions such as
  1436 
  1437   inductive EVEN ODD
  1438     intrs
  1439       null "0 : EVEN"
  1440       oddI "n : EVEN ==> Suc n : ODD"
  1441       evenI "n : ODD ==> Suc n : EVEN"
  1442 
  1443 new theorem list "elims" contains an elimination rule for each of the
  1444 recursive sets; inductive definitions now handle disjunctive premises
  1445 correctly (also ZF);
  1446 
  1447 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1448 "mutual_induct" no longer exists - the induction rule is always
  1449 contained in "induct";
  1450 
  1451 
  1452 * HOL/datatype package re-implemented and greatly improved: now
  1453 supports mutually recursive datatypes such as
  1454 
  1455   datatype
  1456     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1457             | SUM ('a aexp) ('a aexp)
  1458             | DIFF ('a aexp) ('a aexp)
  1459             | NUM 'a
  1460   and
  1461     'a bexp = LESS ('a aexp) ('a aexp)
  1462             | AND ('a bexp) ('a bexp)
  1463             | OR ('a bexp) ('a bexp)
  1464 
  1465 as well as indirectly recursive datatypes such as
  1466 
  1467   datatype
  1468     ('a, 'b) term = Var 'a
  1469                   | App 'b ((('a, 'b) term) list)
  1470 
  1471 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1472 induction on mutually / indirectly recursive datatypes.
  1473 
  1474 Primrec equations are now stored in theory and can be accessed via
  1475 <function_name>.simps.
  1476 
  1477 INCOMPATIBILITIES:
  1478 
  1479   - Theories using datatypes must now have theory Datatype as an
  1480     ancestor.
  1481   - The specific <typename>.induct_tac no longer exists - use the
  1482     generic induct_tac instead.
  1483   - natE has been renamed to nat.exhaust - use exhaust_tac
  1484     instead of res_inst_tac ... natE. Note that the variable
  1485     names in nat.exhaust differ from the names in natE, this
  1486     may cause some "fragile" proofs to fail.
  1487   - The theorems split_<typename>_case and split_<typename>_case_asm
  1488     have been renamed to <typename>.split and <typename>.split_asm.
  1489   - Since default sorts of type variables are now handled correctly,
  1490     some datatype definitions may have to be annotated with explicit
  1491     sort constraints.
  1492   - Primrec definitions no longer require function name and type
  1493     of recursive argument.
  1494 
  1495 Consider using isatool fixdatatype to adapt your theories and proof
  1496 scripts to the new package (backup your sources first!).
  1497 
  1498 
  1499 * HOL/record package: considerably improved implementation; now
  1500 includes concrete syntax for record types, terms, updates; theorems
  1501 for surjective pairing and splitting !!-bound record variables; proof
  1502 support is as follows:
  1503 
  1504   1) standard conversions (selectors or updates applied to record
  1505 constructor terms) are part of the standard simpset;
  1506 
  1507   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1508 made part of standard simpset and claset via addIffs;
  1509 
  1510   3) a tactic for record field splitting (record_split_tac) is part of
  1511 the standard claset (addSWrapper);
  1512 
  1513 To get a better idea about these rules you may retrieve them via
  1514 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1515 the name of your record type.
  1516 
  1517 The split tactic 3) conceptually simplifies by the following rule:
  1518 
  1519   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1520 
  1521 Thus any record variable that is bound by meta-all will automatically
  1522 blow up into some record constructor term, consequently the
  1523 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1524 solve record problems automatically.
  1525 
  1526 
  1527 * reorganized the main HOL image: HOL/Integ and String loaded by
  1528 default; theory Main includes everything;
  1529 
  1530 * automatic simplification of integer sums and comparisons, using cancellation;
  1531 
  1532 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1533 
  1534 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1535 
  1536 * many new identities for unions, intersections, set difference, etc.;
  1537 
  1538 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1539 called split_if, split_split, split_sum_case and split_nat_case (to go
  1540 with add/delsplits);
  1541 
  1542 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1543 (?x::unit) = (); this is made part of the default simpset, which COULD
  1544 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1545 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1546 unit_abs_eta_conv is added in order to counter the effect of
  1547 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1548 %u.f();
  1549 
  1550 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1551 makes more sense);
  1552 
  1553 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1554   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1555   disjointness reasoning but breaking a few old proofs.
  1556 
  1557 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1558 to 'converse' from 'inverse' (for compatibility with ZF and some
  1559 literature);
  1560 
  1561 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1562 the well-founded relation;
  1563 
  1564 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1565     Compl A.  The "Compl" syntax remains available as input syntax for this
  1566     release ONLY.
  1567 
  1568 * HOL/Update: new theory of function updates:
  1569     f(a:=b) == %x. if x=a then b else f x
  1570 may also be iterated as in f(a:=b,c:=d,...);
  1571 
  1572 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1573 
  1574 * HOL/List:
  1575   - new function list_update written xs[i:=v] that updates the i-th
  1576     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1577   - new function `upt' written [i..j(] which generates the list
  1578     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1579     bound write [i..j], which is a shorthand for [i..j+1(].
  1580   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1581 
  1582 * HOL/Arith:
  1583   - removed 'pred' (predecessor) function;
  1584   - generalized some theorems about n-1;
  1585   - many new laws about "div" and "mod";
  1586   - new laws about greatest common divisors (see theory ex/Primes);
  1587 
  1588 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1589 instead of "inverse";
  1590 
  1591 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1592   of the multiset ordering;
  1593 
  1594 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1595   (not included by default);
  1596 
  1597 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1598 
  1599 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1600   programs, i.e. different program variables may have different types.
  1601 
  1602 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1603   [previously, this check worked only if the rewrite rule was unconditional]
  1604   Now rew can involve either definitions or equalities (either == or =).
  1605 
  1606 
  1607 *** ZF ***
  1608 
  1609 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1610   only the theorems proved on ZF.ML;
  1611 
  1612 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1613   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1614   disjointness reasoning but breaking a few old proofs.
  1615 
  1616 * ZF/Update: new theory of function updates
  1617     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1618   may also be iterated as in f(a:=b,c:=d,...);
  1619 
  1620 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1621 
  1622 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1623   [previously, this check worked only if the rewrite rule was unconditional]
  1624   Now rew can involve either definitions or equalities (either == or =).
  1625 
  1626 * case_tac provided for compatibility with HOL
  1627     (like the old excluded_middle_tac, but with subgoals swapped)
  1628 
  1629 
  1630 *** Internal programming interfaces ***
  1631 
  1632 * Pure: several new basic modules made available for general use, see
  1633 also src/Pure/README;
  1634 
  1635 * improved the theory data mechanism to support encapsulation (data
  1636 kind name replaced by private Object.kind, acting as authorization
  1637 key); new type-safe user interface via functor TheoryDataFun; generic
  1638 print_data function becomes basically useless;
  1639 
  1640 * removed global_names compatibility flag -- all theory declarations
  1641 are qualified by default;
  1642 
  1643 * module Pure/Syntax now offers quote / antiquote translation
  1644 functions (useful for Hoare logic etc. with implicit dependencies);
  1645 see HOL/ex/Antiquote for an example use;
  1646 
  1647 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1648 cterm -> thm;
  1649 
  1650 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1651 subgoal;
  1652 
  1653 * Display.print_goals function moved to Locale.print_goals;
  1654 
  1655 * standard print function for goals supports current_goals_markers
  1656 variable for marking begin of proof, end of proof, start of goal; the
  1657 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1658 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1659 for example;
  1660 
  1661 
  1662 
  1663 New in Isabelle98 (January 1998)
  1664 --------------------------------
  1665 
  1666 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1667 
  1668 * changed lexical syntax of terms / types: dots made part of long
  1669 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1670 
  1671 * simpset (and claset) reference variable replaced by functions
  1672 simpset / simpset_ref;
  1673 
  1674 * no longer supports theory aliases (via merge) and non-trivial
  1675 implicit merge of thms' signatures;
  1676 
  1677 * most internal names of constants changed due to qualified names;
  1678 
  1679 * changed Pure/Sequence interface (see Pure/seq.ML);
  1680 
  1681 
  1682 *** General Changes ***
  1683 
  1684 * hierachically structured name spaces (for consts, types, axms, thms
  1685 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1686 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1687 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1688 long_names for fully qualified output names; NOTE: ML programs
  1689 (special tactics, packages etc.) referring to internal names may have
  1690 to be adapted to cope with fully qualified names; in case of severe
  1691 backward campatibility problems try setting 'global_names' at compile
  1692 time to have enrything declared within a flat name space; one may also
  1693 fine tune name declarations in theories via the 'global' and 'local'
  1694 section;
  1695 
  1696 * reimplemented the implicit simpset and claset using the new anytype
  1697 data filed in signatures; references simpset:simpset ref etc. are
  1698 replaced by functions simpset:unit->simpset and
  1699 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1700 to patch your ML files accordingly;
  1701 
  1702 * HTML output now includes theory graph data for display with Java
  1703 applet or isatool browser; data generated automatically via isatool
  1704 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1705 
  1706 * defs may now be conditional; improved rewrite_goals_tac to handle
  1707 conditional equations;
  1708 
  1709 * defs now admits additional type arguments, using TYPE('a) syntax;
  1710 
  1711 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1712 creates a new theory node; implicit merge of thms' signatures is
  1713 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1714 transfer:theory->thm->thm in (rare) cases;
  1715 
  1716 * improved handling of draft signatures / theories; draft thms (and
  1717 ctyps, cterms) are automatically promoted to real ones;
  1718 
  1719 * slightly changed interfaces for oracles: admit many per theory, named
  1720 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1721 
  1722 * print_goals: optional output of const types (set show_consts and
  1723 show_types);
  1724 
  1725 * improved output of warnings (###) and errors (***);
  1726 
  1727 * subgoal_tac displays a warning if the new subgoal has type variables;
  1728 
  1729 * removed old README and Makefiles;
  1730 
  1731 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1732 
  1733 * removed obsolete init_pps and init_database;
  1734 
  1735 * deleted the obsolete tactical STATE, which was declared by
  1736     fun STATE tacfun st = tacfun st st;
  1737 
  1738 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1739 (which abbreviates $HOME);
  1740 
  1741 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1742 use isatool fixseq to adapt your ML programs (this works for fully
  1743 qualified references to the Sequence structure only!);
  1744 
  1745 * use_thy no longer requires writable current directory; it always
  1746 reloads .ML *and* .thy file, if either one is out of date;
  1747 
  1748 
  1749 *** Classical Reasoner ***
  1750 
  1751 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1752 tactics that use classical reasoning to simplify a subgoal without
  1753 splitting it into several subgoals;
  1754 
  1755 * Safe_tac: like safe_tac but uses the default claset;
  1756 
  1757 
  1758 *** Simplifier ***
  1759 
  1760 * added simplification meta rules:
  1761     (asm_)(full_)simplify: simpset -> thm -> thm;
  1762 
  1763 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1764 logics (again);
  1765 
  1766 * added prems argument to simplification procedures;
  1767 
  1768 * HOL, FOL, ZF: added infix function `addsplits':
  1769   instead of `<simpset> setloop (split_tac <thms>)'
  1770   you can simply write `<simpset> addsplits <thms>'
  1771 
  1772 
  1773 *** Syntax ***
  1774 
  1775 * TYPE('a) syntax for type reflection terms;
  1776 
  1777 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1778 
  1779 * pretty printer: changed order of mixfix annotation preference (again!);
  1780 
  1781 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1782 
  1783 
  1784 *** HOL ***
  1785 
  1786 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1787   with `addloop' of the simplifier to faciliate case splitting in premises.
  1788 
  1789 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1790 
  1791 * HOL/Auth: new protocol proofs including some for the Internet
  1792   protocol TLS;
  1793 
  1794 * HOL/Map: new theory of `maps' a la VDM;
  1795 
  1796 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1797 cancelling out common nat summands from =, <, <= (in)equalities, or
  1798 differences; simplification procedures nat_cancel_factor for
  1799 cancelling common factor from =, <, <= (in)equalities over natural
  1800 sums; nat_cancel contains both kinds of procedures, it is installed by
  1801 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1802 
  1803 * HOL/simplifier: terms of the form
  1804   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1805   are rewritten to
  1806   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1807   and those of the form
  1808   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1809   are rewritten to
  1810   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1811 
  1812 * HOL/datatype
  1813   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1814 
  1815   P(t_case f1 ... fn x) =
  1816      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1817         ...
  1818        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1819      )
  1820 
  1821   and a theorem `split_t_case_asm' of the form
  1822 
  1823   P(t_case f1 ... fn x) =
  1824     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1825         ...
  1826        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1827      )
  1828   which can be added to a simpset via `addsplits'. The existing theorems
  1829   expand_list_case and expand_option_case have been renamed to
  1830   split_list_case and split_option_case.
  1831 
  1832 * HOL/Arithmetic:
  1833   - `pred n' is automatically converted to `n-1'.
  1834     Users are strongly encouraged not to use `pred' any longer,
  1835     because it will disappear altogether at some point.
  1836   - Users are strongly encouraged to write "0 < n" rather than
  1837     "n ~= 0". Theorems and proof tools have been modified towards this
  1838     `standard'.
  1839 
  1840 * HOL/Lists:
  1841   the function "set_of_list" has been renamed "set" (and its theorems too);
  1842   the function "nth" now takes its arguments in the reverse order and
  1843   has acquired the infix notation "!" as in "xs!n".
  1844 
  1845 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1846 
  1847 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1848   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1849 
  1850 * HOL/record: extensible records with schematic structural subtyping
  1851 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1852 still lacks various theorems and concrete record syntax;
  1853 
  1854 
  1855 *** HOLCF ***
  1856 
  1857 * removed "axioms" and "generated by" sections;
  1858 
  1859 * replaced "ops" section by extended "consts" section, which is capable of
  1860   handling the continuous function space "->" directly;
  1861 
  1862 * domain package:
  1863   . proves theorems immediately and stores them in the theory,
  1864   . creates hierachical name space,
  1865   . now uses normal mixfix annotations (instead of cinfix...),
  1866   . minor changes to some names and values (for consistency),
  1867   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1868   . separator between mutual domain defs: changed "," to "and",
  1869   . improved handling of sort constraints;  now they have to
  1870     appear on the left-hand side of the equations only;
  1871 
  1872 * fixed LAM <x,y,zs>.b syntax;
  1873 
  1874 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1875 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1876 
  1877 
  1878 *** FOL and ZF ***
  1879 
  1880 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1881   with `addloop' of the simplifier to faciliate case splitting in premises.
  1882 
  1883 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1884 in HOL, they strip ALL and --> from proved theorems;
  1885 
  1886 
  1887 
  1888 New in Isabelle94-8 (May 1997)
  1889 ------------------------------
  1890 
  1891 *** General Changes ***
  1892 
  1893 * new utilities to build / run / maintain Isabelle etc. (in parts
  1894 still somewhat experimental); old Makefiles etc. still functional;
  1895 
  1896 * new 'Isabelle System Manual';
  1897 
  1898 * INSTALL text, together with ./configure and ./build scripts;
  1899 
  1900 * reimplemented type inference for greater efficiency, better error
  1901 messages and clean internal interface;
  1902 
  1903 * prlim command for dealing with lots of subgoals (an easier way of
  1904 setting goals_limit);
  1905 
  1906 
  1907 *** Syntax ***
  1908 
  1909 * supports alternative (named) syntax tables (parser and pretty
  1910 printer); internal interface is provided by add_modesyntax(_i);
  1911 
  1912 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1913 be used in conjunction with the Isabelle symbol font; uses the
  1914 "symbols" syntax table;
  1915 
  1916 * added token_translation interface (may translate name tokens in
  1917 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1918 the current print_mode); IMPORTANT: user print translation functions
  1919 are responsible for marking newly introduced bounds
  1920 (Syntax.mark_boundT);
  1921 
  1922 * token translations for modes "xterm" and "xterm_color" that display
  1923 names in bold, underline etc. or colors (which requires a color
  1924 version of xterm);
  1925 
  1926 * infixes may now be declared with names independent of their syntax;
  1927 
  1928 * added typed_print_translation (like print_translation, but may
  1929 access type of constant);
  1930 
  1931 
  1932 *** Classical Reasoner ***
  1933 
  1934 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1935 some limitations.  Blast_tac...
  1936   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1937   + ignores elimination rules that don't have the correct format
  1938         (the conclusion MUST be a formula variable)
  1939   + ignores types, which can make HOL proofs fail
  1940   + rules must not require higher-order unification, e.g. apply_type in ZF
  1941     [message "Function Var's argument not a bound variable" relates to this]
  1942   + its proof strategy is more general but can actually be slower
  1943 
  1944 * substitution with equality assumptions no longer permutes other
  1945 assumptions;
  1946 
  1947 * minor changes in semantics of addafter (now called addaltern); renamed
  1948 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1949 (and access functions for it);
  1950 
  1951 * improved combination of classical reasoner and simplifier:
  1952   + functions for handling clasimpsets
  1953   + improvement of addss: now the simplifier is called _after_ the
  1954     safe steps.
  1955   + safe variant of addss called addSss: uses safe simplifications
  1956     _during_ the safe steps. It is more complete as it allows multiple
  1957     instantiations of unknowns (e.g. with slow_tac).
  1958 
  1959 *** Simplifier ***
  1960 
  1961 * added interface for simplification procedures (functions that
  1962 produce *proven* rewrite rules on the fly, depending on current
  1963 redex);
  1964 
  1965 * ordering on terms as parameter (used for ordered rewriting);
  1966 
  1967 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1968 
  1969 * the solver is now split into a safe and an unsafe part.
  1970 This should be invisible for the normal user, except that the
  1971 functions setsolver and addsolver have been renamed to setSolver and
  1972 addSolver; added safe_asm_full_simp_tac;
  1973 
  1974 
  1975 *** HOL ***
  1976 
  1977 * a generic induction tactic `induct_tac' which works for all datatypes and
  1978 also for type `nat';
  1979 
  1980 * a generic case distinction tactic `exhaust_tac' which works for all
  1981 datatypes and also for type `nat';
  1982 
  1983 * each datatype comes with a function `size';
  1984 
  1985 * patterns in case expressions allow tuple patterns as arguments to
  1986 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1987 
  1988 * primrec now also works with type nat;
  1989 
  1990 * recdef: a new declaration form, allows general recursive functions to be
  1991 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1992 
  1993 * the constant for negation has been renamed from "not" to "Not" to
  1994 harmonize with FOL, ZF, LK, etc.;
  1995 
  1996 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1997 infinite lists;
  1998 
  1999 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2000 
  2001 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2002 problems in commutative rings, using axiomatic type classes for + and *;
  2003 
  2004 * more examples in HOL/MiniML and HOL/Auth;
  2005 
  2006 * more default rewrite rules for quantifiers, union/intersection;
  2007 
  2008 * a new constant `arbitrary == @x.False';
  2009 
  2010 * HOLCF/IOA replaces old HOL/IOA;
  2011 
  2012 * HOLCF changes: derived all rules and arities
  2013   + axiomatic type classes instead of classes
  2014   + typedef instead of faking type definitions
  2015   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2016   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2017   + eliminated the types void, one, tr
  2018   + use unit lift and bool lift (with translations) instead of one and tr
  2019   + eliminated blift from Lift3.thy (use Def instead of blift)
  2020   all eliminated rules are derived as theorems --> no visible changes ;
  2021 
  2022 
  2023 *** ZF ***
  2024 
  2025 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2026 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2027 as ZF_cs addSIs [equalityI];
  2028 
  2029 
  2030 
  2031 New in Isabelle94-7 (November 96)
  2032 ---------------------------------
  2033 
  2034 * allowing negative levels (as offsets) in prlev and choplev;
  2035 
  2036 * super-linear speedup for large simplifications;
  2037 
  2038 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2039 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2040 FAIL); can suppress it using the command Delsimps (ex_simps @
  2041 all_simps); De Morgan laws are also now included, by default;
  2042 
  2043 * improved printing of ==>  :  ~:
  2044 
  2045 * new object-logic "Sequents" adds linear logic, while replacing LK
  2046 and Modal (thanks to Sara Kalvala);
  2047 
  2048 * HOL/Auth: correctness proofs for authentication protocols;
  2049 
  2050 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2051 examples on HOL/Auth);
  2052 
  2053 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2054 the rewriter and classical reasoner simultaneously;
  2055 
  2056 * function uresult no longer returns theorems in "standard" format;
  2057 regain previous version by: val uresult = standard o uresult;
  2058 
  2059 
  2060 
  2061 New in Isabelle94-6
  2062 -------------------
  2063 
  2064 * oracles -- these establish an interface between Isabelle and trusted
  2065 external reasoners, which may deliver results as theorems;
  2066 
  2067 * proof objects (in particular record all uses of oracles);
  2068 
  2069 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2070 
  2071 * "constdefs" section in theory files;
  2072 
  2073 * "primrec" section (HOL) no longer requires names;
  2074 
  2075 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2076 
  2077 
  2078 
  2079 New in Isabelle94-5
  2080 -------------------
  2081 
  2082 * reduced space requirements;
  2083 
  2084 * automatic HTML generation from theories;
  2085 
  2086 * theory files no longer require "..." (quotes) around most types;
  2087 
  2088 * new examples, including two proofs of the Church-Rosser theorem;
  2089 
  2090 * non-curried (1994) version of HOL is no longer distributed;
  2091 
  2092 
  2093 
  2094 New in Isabelle94-4
  2095 -------------------
  2096 
  2097 * greatly reduced space requirements;
  2098 
  2099 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2100 
  2101 * searchable theorem database (see the section "Retrieving theorems" on
  2102 page 8 of the Reference Manual);
  2103 
  2104 * new examples, including Grabczewski's monumental case study of the
  2105 Axiom of Choice;
  2106 
  2107 * The previous version of HOL renamed to Old_HOL;
  2108 
  2109 * The new version of HOL (previously called CHOL) uses a curried syntax
  2110 for functions.  Application looks like f a b instead of f(a,b);
  2111 
  2112 * Mutually recursive inductive definitions finally work in HOL;
  2113 
  2114 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2115 translates to the operator "split";
  2116 
  2117 
  2118 
  2119 New in Isabelle94-3
  2120 -------------------
  2121 
  2122 * new infix operator, addss, allowing the classical reasoner to
  2123 perform simplification at each step of its search.  Example:
  2124         fast_tac (cs addss ss)
  2125 
  2126 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2127 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2128 look like (a,b) instead of <a,b>;
  2129 
  2130 * PLEASE NOTE: CHOL will eventually replace HOL!
  2131 
  2132 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2133 It translates to the operator "split".  A new theory of integers is available;
  2134 
  2135 * In ZF, integer numerals now denote two's-complement binary integers.
  2136 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2137 
  2138 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2139 of the Axiom of Choice;
  2140 
  2141 
  2142 
  2143 New in Isabelle94-2
  2144 -------------------
  2145 
  2146 * Significantly faster resolution;
  2147 
  2148 * the different sections in a .thy file can now be mixed and repeated
  2149 freely;
  2150 
  2151 * Database of theorems for FOL, HOL and ZF.  New
  2152 commands including qed, qed_goal and bind_thm store theorems in the database.
  2153 
  2154 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2155 a given theory (thms_of), or find out what theory a theorem was proved in
  2156 (theory_of_thm);
  2157 
  2158 * Bugs fixed in the inductive definition and datatype packages;
  2159 
  2160 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2161 and HOL_dup_cs obsolete;
  2162 
  2163 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2164 have been removed;
  2165 
  2166 * Simpler definition of function space in ZF;
  2167 
  2168 * new results about cardinal and ordinal arithmetic in ZF;
  2169 
  2170 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2171 types;
  2172 
  2173 
  2174 $Id$