NEWS
author paulson
Wed Jan 16 17:53:22 2002 +0100 (2002-01-16)
changeset 12777 70b2651af635
parent 12769 0f70bfe510ee
child 12832 c31b44286a8a
permissions -rw-r--r--
Isar version of ZF/AC
     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: symbolic syntax for x^2 (numeral 2);
   188 
   189 * HOL: the class of all HOL types is now called "type" rather than
   190 "term"; INCOMPATIBILITY, need to adapt references to this type class
   191 in axclass/classes, instance/arities, and (usually rare) occurrences
   192 in typings (of consts etc.); internally the class is called
   193 "HOL.type", ML programs should refer to HOLogic.typeS;
   194 
   195 * HOL/record package improvements:
   196   - new derived operations "fields" to build a partial record section,
   197     "extend" to promote a fixed record to a record scheme, and
   198     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   199     declared as simp by default;
   200   - shared operations ("more", "fields", etc.) now need to be always
   201     qualified) --- potential INCOMPATIBILITY;
   202   - removed "make_scheme" operations (use "make" with "extend") --
   203     INCOMPATIBILITY;
   204   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   205   - provides cases/induct rules for use with corresponding Isar
   206     methods (for concrete records, record schemes, concrete more
   207     parts, and schematic more parts -- in that order);
   208   - internal definitions directly based on a light-weight abstract
   209     theory of product types over typedef rather than datatype;
   210 
   211 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   212 
   213 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   214 (beware of argument permutation!);
   215 
   216 * HOL: linorder_less_split superseded by linorder_cases;
   217 
   218 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   219 to peripheral theory "Hilbert_Choice";
   220 
   221 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   222 in this (rare) case use:
   223 
   224   delSWrapper "split_all_tac"
   225   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   226 
   227 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   228 MAY FAIL;
   229 
   230 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   231 Isabelle's type classes, ^ on functions and relations has too general
   232 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   233 necessary to attach explicit type constraints;
   234 
   235 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   236 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   237 (eg "compI" -> "rel_compI").
   238 
   239 * HOL: syntax translations now work properly with numerals and records
   240 expressions;
   241 
   242 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   243 of "lam" -- INCOMPATIBILITY;
   244 
   245 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   246 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   247 renamed "Product_Type.unit";
   248 
   249 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   250 
   251 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   252 Florian Kammüller);
   253 
   254 * HOL/IMP: updated and converted to new-style theory format; several
   255 parts turned into readable document, with proper Isar proof texts and
   256 some explanations (by Gerwin Klein);
   257 
   258 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   259 
   260 * HOL-Hyperreal is now a logic image;
   261 
   262 
   263 *** HOLCF ***
   264 
   265 * Isar: consts/constdefs supports mixfix syntax for continuous
   266 operations;
   267 
   268 * Isar: domain package adapted to new-style theory format, e.g. see
   269 HOLCF/ex/Dnat.thy;
   270 
   271 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   272 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   273 lift.induct_tac, always use UU instead of Undef;
   274 
   275 * HOLCF/IMP: updated and converted to new-style theory;
   276 
   277 
   278 *** ZF ***
   279 
   280 * Isar: proper integration of logic-specific tools and packages,
   281 including theory commands '(co)inductive', '(co)datatype',
   282 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   283 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   284 
   285 * theory Main no longer includes AC; for the Axiom of Choice, base
   286 your theory on Main_ZFC;
   287 
   288 * the integer library now covers quotients and remainders, with many
   289 laws relating division to addition, multiplication, etc.;
   290 
   291 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   292 typeless version of the formalism;
   293 
   294 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory format;
   295 
   296 * ZF/Induct: new directory for examples of inductive definitions,
   297 including theory Multiset for multiset orderings; converted to
   298 new-style theory format;
   299 
   300 
   301 *** General ***
   302 
   303 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   304 variable proof controls level of detail: 0 = no proofs (only oracle
   305 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   306 also ref manual for further ML interfaces;
   307 
   308 * Pure/axclass: removed obsolete ML interface
   309 goal_subclass/goal_arity;
   310 
   311 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   312 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   313 separate tokens, so expressions involving minus need to be spaced
   314 properly;
   315 
   316 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   317 rather than "infixl" or "infixr";
   318 
   319 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   320 sort constraint specifications in type inference; e.g. "x::_::foo"
   321 ensures that the type of "x" is of sort "foo" (but not necessarily a
   322 type variable);
   323 
   324 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   325 control output of nested => (types); the default behavior is
   326 "type_brackets";
   327 
   328 * Pure/syntax: builtin parse translation for "_constify" turns valued
   329 tokens into AST constants;
   330 
   331 * Pure/syntax: prefer later declarations of translations and print
   332 translation functions; potential INCOMPATIBILITY: need to reverse
   333 multiple declarations for same syntax element constant;
   334 
   335 * Provers/classical: renamed addaltern to addafter, addSaltern to
   336 addSafter;
   337 
   338 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   339 as well;
   340 
   341 * system: tested support for MacOS X; should be able to get Isabelle +
   342 Proof General to work in a plain Terminal after installing Poly/ML
   343 (e.g. from the Isabelle distribution area) and GNU bash alone
   344 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   345 support requires further installations, e.g. from
   346 http://fink.sourceforge.net/);
   347 
   348 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   349 
   350 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   351 of 40 MB), cf. ML_OPTIONS;
   352 
   353 * system: Proof General keywords specification is now part of the
   354 Isabelle distribution (see etc/isar-keywords.el);
   355 
   356 * system: support for persistent Proof General sessions (refrain from
   357 outdating all loaded theories on startup); user may create writable
   358 logic images like this: ``isabelle -q HOL Test'';
   359 
   360 * system: smart selection of Isabelle process versus Isabelle
   361 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   362 run both "isabelle" and "Isabelle" even if file names are badly
   363 damaged (executable inspects the case of the first letter of its own
   364 name); added separate "isabelle-process" and "isabelle-interface";
   365 
   366 * system: refrain from any attempt at filtering input streams; no
   367 longer support ``8bit'' encoding of old isabelle font, instead proper
   368 iso-latin characters may now be used; the related isatools
   369 "symbolinput" and "nonascii" have disappeared as well;
   370 
   371 * system: removed old "xterm" interface (the print modes "xterm" and
   372 "xterm_color" are still available for direct use in a suitable
   373 terminal);
   374 
   375 
   376 
   377 New in Isabelle99-2 (February 2001)
   378 -----------------------------------
   379 
   380 *** Overview of INCOMPATIBILITIES ***
   381 
   382 * HOL: please note that theories in the Library and elsewhere often use the
   383 new-style (Isar) format; to refer to their theorems in an ML script you must
   384 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   385 
   386 * HOL: inductive package no longer splits induction rule aggressively,
   387 but only as far as specified by the introductions given; the old
   388 format may be recovered via ML function complete_split_rule or attribute
   389 'split_rule (complete)';
   390 
   391 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   392 gfp_Tarski to gfp_unfold;
   393 
   394 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   395 
   396 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   397 relation); infix "^^" has been renamed "``"; infix "``" has been
   398 renamed "`"; "univalent" has been renamed "single_valued";
   399 
   400 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   401 operation;
   402 
   403 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   404 
   405 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   406 
   407 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   408 consequence, it is no longer monotonic wrt. the local goal context
   409 (which is now passed through the inductive cases);
   410 
   411 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   412 \<gg> to \<ggreater>;
   413 
   414 
   415 *** Document preparation ***
   416 
   417 * \isabellestyle{NAME} selects version of Isabelle output (currently
   418 available: are "it" for near math-mode best-style output, "sl" for
   419 slanted text style, and "tt" for plain type-writer; if no
   420 \isabellestyle command is given, output is according to slanted
   421 type-writer);
   422 
   423 * support sub/super scripts (for single symbols only), input syntax is
   424 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   425 
   426 * some more standard symbols; see Appendix A of the system manual for
   427 the complete list of symbols defined in isabellesym.sty;
   428 
   429 * improved isabelle style files; more abstract symbol implementation
   430 (should now use \isamath{...} and \isatext{...} in custom symbol
   431 definitions);
   432 
   433 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   434 state; Note that presentation of goal states does not conform to
   435 actual human-readable proof documents.  Please do not include goal
   436 states into document output unless you really know what you are doing!
   437 
   438 * proper indentation of antiquoted output with proportional LaTeX
   439 fonts;
   440 
   441 * no_document ML operator temporarily disables LaTeX document
   442 generation;
   443 
   444 * isatool unsymbolize tunes sources for plain ASCII communication;
   445 
   446 
   447 *** Isar ***
   448 
   449 * Pure: Isar now suffers initial goal statements to contain unbound
   450 schematic variables (this does not conform to actual readable proof
   451 documents, due to unpredictable outcome and non-compositional proof
   452 checking); users who know what they are doing may use schematic goals
   453 for Prolog-style synthesis of proven results;
   454 
   455 * Pure: assumption method (an implicit finishing) now handles actual
   456 rules as well;
   457 
   458 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   459 initial goal, declare "that" only as Pure intro (only for single
   460 steps); the "that" rule assumption may now be involved in implicit
   461 finishing, thus ".." becomes a feasible for trivial obtains;
   462 
   463 * Pure: default proof step now includes 'intro_classes'; thus trivial
   464 instance proofs may be performed by "..";
   465 
   466 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   467 statements as well;
   468 
   469 * Pure: more robust selection of calculational rules;
   470 
   471 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   472 rule (as well as the assumption rule);
   473 
   474 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   475 lemmas, using the graph browser tool;
   476 
   477 * Pure: predict failure of "show" in interactive mode;
   478 
   479 * Pure: 'thms_containing' now takes actual terms as arguments;
   480 
   481 * HOL: improved method 'induct' --- now handles non-atomic goals
   482 (potential INCOMPATIBILITY); tuned error handling;
   483 
   484 * HOL: cases and induct rules now provide explicit hints about the
   485 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   486 any remaining facts are inserted into the goal verbatim;
   487 
   488 * HOL: local contexts (aka cases) may now contain term bindings as
   489 well; the 'cases' and 'induct' methods new provide a ?case binding for
   490 the result to be shown in each case;
   491 
   492 * HOL: added 'recdef_tc' command;
   493 
   494 * isatool convert assists in eliminating legacy ML scripts;
   495 
   496 
   497 *** HOL ***
   498 
   499 * HOL/Library: a collection of generic theories to be used together
   500 with main HOL; the theory loader path already includes this directory
   501 by default; the following existing theories have been moved here:
   502 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   503 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   504 
   505 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   506 modelling and verification task performed in Isabelle/HOL +
   507 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   508 
   509 * HOL/Algebra: special summation operator SUM no longer exists, it has
   510 been replaced by setsum; infix 'assoc' now has priority 50 (like
   511 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   512 'domain', this makes the theory consistent with mathematical
   513 literature;
   514 
   515 * HOL basics: added overloaded operations "inverse" and "divide"
   516 (infix "/"), syntax for generic "abs" operation, generic summation
   517 operator \<Sum>;
   518 
   519 * HOL/typedef: simplified package, provide more useful rules (see also
   520 HOL/subset.thy);
   521 
   522 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   523 now expressed as a proper nested rule (old-style tactic scripts may
   524 require atomize_strip_tac to cope with non-atomic premises);
   525 
   526 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   527 to "split_conv" (old name still available for compatibility);
   528 
   529 * HOL: improved concrete syntax for strings (e.g. allows translation
   530 rules with string literals);
   531 
   532 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   533  and Fleuriot's mechanization of analysis, including the transcendental
   534  functions for the reals;
   535 
   536 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   537 
   538 
   539 *** CTT ***
   540 
   541 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   542 "lam" is displayed as TWO lambda-symbols
   543 
   544 * CTT: theory Main now available, containing everything (that is, Bool
   545 and Arith);
   546 
   547 
   548 *** General ***
   549 
   550 * Pure: the Simplifier has been implemented properly as a derived rule
   551 outside of the actual kernel (at last!); the overall performance
   552 penalty in practical applications is about 50%, while reliability of
   553 the Isabelle inference kernel has been greatly improved;
   554 
   555 * print modes "brackets" and "no_brackets" control output of nested =>
   556 (types) and ==> (props); the default behaviour is "brackets";
   557 
   558 * Provers: fast_tac (and friends) now handle actual object-logic rules
   559 as assumptions as well;
   560 
   561 * system: support Poly/ML 4.0;
   562 
   563 * system: isatool install handles KDE version 1 or 2;
   564 
   565 
   566 
   567 New in Isabelle99-1 (October 2000)
   568 ----------------------------------
   569 
   570 *** Overview of INCOMPATIBILITIES ***
   571 
   572 * HOL: simplification of natural numbers is much changed; to partly
   573 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   574 issue the following ML commands:
   575 
   576   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   577   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   578 
   579 * HOL: simplification no longer dives into case-expressions; this is
   580 controlled by "t.weak_case_cong" for each datatype t;
   581 
   582 * HOL: nat_less_induct renamed to less_induct;
   583 
   584 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   585 fixsome to patch .thy and .ML sources automatically;
   586 
   587   select_equality  -> some_equality
   588   select_eq_Ex     -> some_eq_ex
   589   selectI2EX       -> someI2_ex
   590   selectI2         -> someI2
   591   selectI          -> someI
   592   select1_equality -> some1_equality
   593   Eps_sym_eq       -> some_sym_eq_trivial
   594   Eps_eq           -> some_eq_trivial
   595 
   596 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   597 
   598 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   599 instead);
   600 
   601 * HOL: the recursion equations generated by 'recdef' are now called
   602 f.simps instead of f.rules;
   603 
   604 * HOL: qed_spec_mp now also handles bounded ALL as well;
   605 
   606 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   607 sometimes be needed;
   608 
   609 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   610 
   611 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   612 
   613 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   614 product is now "<*>" instead of "Times"; the lexicographic product is
   615 now "<*lex*>" instead of "**";
   616 
   617 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   618 of main HOL, but was unused); better use HOL's datatype package;
   619 
   620 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   621 the old syntax may be recovered as follows:
   622 
   623   syntax (symbols)
   624     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   625       (infixl "\\<oplus>" 100)
   626 
   627 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   628 
   629 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   630 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   631 internally;
   632 
   633 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   634 changed from A/r to A//r;
   635 
   636 * ZF: new treatment of arithmetic (nat & int) may break some old
   637 proofs;
   638 
   639 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   640 rulify -> rule_format, elimify -> elim_format, ...);
   641 
   642 * Isar/Provers: intro/elim/dest attributes changed; renamed
   643 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   644 should have to change intro!! to intro? only); replaced "delrule" by
   645 "rule del";
   646 
   647 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   648 
   649 * Provers: strengthened force_tac by using new first_best_tac;
   650 
   651 * LaTeX document preparation: several changes of isabelle.sty (see
   652 lib/texinputs);
   653 
   654 
   655 *** Document preparation ***
   656 
   657 * formal comments (text blocks etc.) in new-style theories may now
   658 contain antiquotations of thm/prop/term/typ/text to be presented
   659 according to latex print mode; concrete syntax is like this:
   660 @{term[show_types] "f(x) = a + x"};
   661 
   662 * isatool mkdir provides easy setup of Isabelle session directories,
   663 including proper document sources;
   664 
   665 * generated LaTeX sources are now deleted after successful run
   666 (isatool document -c); may retain a copy somewhere else via -D option
   667 of isatool usedir;
   668 
   669 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   670 style files, achieving self-contained LaTeX sources and simplifying
   671 LaTeX debugging;
   672 
   673 * old-style theories now produce (crude) LaTeX output as well;
   674 
   675 * browser info session directories are now self-contained (may be put
   676 on WWW server seperately); improved graphs of nested sessions; removed
   677 graph for 'all sessions';
   678 
   679 * several improvements in isabelle style files; \isabellestyle{it}
   680 produces fake math mode output; \isamarkupheader is now \section by
   681 default; see lib/texinputs/isabelle.sty etc.;
   682 
   683 
   684 *** Isar ***
   685 
   686 * Isar/Pure: local results and corresponding term bindings are now
   687 subject to Hindley-Milner polymorphism (similar to ML); this
   688 accommodates incremental type-inference very nicely;
   689 
   690 * Isar/Pure: new derived language element 'obtain' supports
   691 generalized existence reasoning;
   692 
   693 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   694 support accumulation of results, without applying any rules yet;
   695 useful to collect intermediate results without explicit name
   696 references, and for use with transitivity rules with more than 2
   697 premises;
   698 
   699 * Isar/Pure: scalable support for case-analysis type proofs: new
   700 'case' language element refers to local contexts symbolically, as
   701 produced by certain proof methods; internally, case names are attached
   702 to theorems as "tags";
   703 
   704 * Isar/Pure: theory command 'hide' removes declarations from
   705 class/type/const name spaces;
   706 
   707 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   708 indicate potential overloading;
   709 
   710 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   711 
   712 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   713 "{a,b,c}" instead of {a,b,c};
   714 
   715 * Isar/Pure now provides its own version of intro/elim/dest
   716 attributes; useful for building new logics, but beware of confusion
   717 with the version in Provers/classical;
   718 
   719 * Isar/Pure: the local context of (non-atomic) goals is provided via
   720 case name 'antecedent';
   721 
   722 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   723 to the current context is now done automatically);
   724 
   725 * Isar/Pure: theory command 'method_setup' provides a simple interface
   726 for definining proof methods in ML;
   727 
   728 * Isar/Provers: intro/elim/dest attributes changed; renamed
   729 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   730 most cases, one should have to change intro!! to intro? only);
   731 replaced "delrule" by "rule del";
   732 
   733 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   734 'symmetric' attribute (the latter supercedes [RS sym]);
   735 
   736 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   737 method modifier); 'simp' method: 'only:' modifier removes loopers as
   738 well (including splits);
   739 
   740 * Isar/Provers: Simplifier and Classical methods now support all kind
   741 of modifiers used in the past, including 'cong', 'iff', etc.
   742 
   743 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   744 of Simplifier and Classical reasoner);
   745 
   746 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   747 now support named cases; major packages (inductive, datatype, primrec,
   748 recdef) support case names and properly name parameters;
   749 
   750 * Isar/HOL: new transitivity rules for substitution in inequalities --
   751 monotonicity conditions are extracted to be proven at end of
   752 calculations;
   753 
   754 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   755 method anyway;
   756 
   757 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   758 split_if split_if_asm; datatype package provides theorems foo.splits =
   759 foo.split foo.split_asm for each datatype;
   760 
   761 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   762 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   763 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   764 use "(cases (simplified))" method in proper proof texts);
   765 
   766 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   767 
   768 * Isar: names of theorems etc. may be natural numbers as well;
   769 
   770 * Isar: 'pr' command: optional arguments for goals_limit and
   771 ProofContext.prems_limit; no longer prints theory contexts, but only
   772 proof states;
   773 
   774 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   775 additional print modes to be specified; e.g. "pr(latex)" will print
   776 proof state according to the Isabelle LaTeX style;
   777 
   778 * Isar: improved support for emulating tactic scripts, including proof
   779 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   780 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   781 (for HOL datatypes);
   782 
   783 * Isar: simplified (more robust) goal selection of proof methods: 1st
   784 goal, all goals, or explicit goal specifier (tactic emulation); thus
   785 'proof method scripts' have to be in depth-first order;
   786 
   787 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   788 
   789 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   790 should instead use individual commands for printing items
   791 (print_commands, print_methods etc.);
   792 
   793 * Isar: added 'nothing' --- the empty list of theorems;
   794 
   795 
   796 *** HOL ***
   797 
   798 * HOL/MicroJava: formalization of a fragment of Java, together with a
   799 corresponding virtual machine and a specification of its bytecode
   800 verifier and a lightweight bytecode verifier, including proofs of
   801 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   802 Cornelia Pusch (see also the homepage of project Bali at
   803 http://isabelle.in.tum.de/Bali/);
   804 
   805 * HOL/Algebra: new theory of rings and univariate polynomials, by
   806 Clemens Ballarin;
   807 
   808 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   809 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   810 Rasmussen;
   811 
   812 * HOL/Lattice: fundamental concepts of lattice theory and order
   813 structures, including duals, properties of bounds versus algebraic
   814 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   815 Theorem for complete lattices etc.; may also serve as a demonstration
   816 for abstract algebraic reasoning using axiomatic type classes, and
   817 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   818 
   819 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   820 von Oheimb;
   821 
   822 * HOL/IMPP: extension of IMP with local variables and mutually
   823 recursive procedures, by David von Oheimb;
   824 
   825 * HOL/Lambda: converted into new-style theory and document;
   826 
   827 * HOL/ex/Multiquote: example of multiple nested quotations and
   828 anti-quotations -- basically a generalized version of de-Bruijn
   829 representation; very useful in avoiding lifting of operations;
   830 
   831 * HOL/record: added general record equality rule to simpset; fixed
   832 select-update simplification procedure to handle extended records as
   833 well; admit "r" as field name;
   834 
   835 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   836 other numeric types and also as the identity of groups, rings, etc.;
   837 
   838 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   839 Types nat and int belong to this axclass;
   840 
   841 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   842    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   843    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   844   two terms #m*u and #n*u are replaced by #(m+n)*u
   845     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   846   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   847     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   848 
   849 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   850 powerful prover for predicate logic but knows nothing of clasets; see
   851 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   852 
   853 * HOL: new version of "case_tac" subsumes both boolean case split and
   854 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   855 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   856 
   857 * HOL: simplification no longer dives into case-expressions: only the
   858 selector expression is simplified, but not the remaining arms; to
   859 enable full simplification of case-expressions for datatype t, you may
   860 remove t.weak_case_cong from the simpset, either globally (Delcongs
   861 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   862 
   863 * HOL/recdef: the recursion equations generated by 'recdef' for
   864 function 'f' are now called f.simps instead of f.rules; if all
   865 termination conditions are proved automatically, these simplification
   866 rules are added to the simpset, as in primrec; rules may be named
   867 individually as well, resulting in a separate list of theorems for
   868 each equation;
   869 
   870 * HOL/While is a new theory that provides a while-combinator. It
   871 permits the definition of tail-recursive functions without the
   872 provision of a termination measure. The latter is necessary once the
   873 invariant proof rule for while is applied.
   874 
   875 * HOL: new (overloaded) notation for the set of elements below/above
   876 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   877 
   878 * HOL: theorems impI, allI, ballI bound as "strip";
   879 
   880 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   881 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   882 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   883 
   884 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   885 
   886 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   887 main HOL, but was unused);
   888 
   889 * HOL: fewer consts declared as global (e.g. have to refer to
   890 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   891 
   892 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   893 in case of overlap with user translations (e.g. judgements over
   894 tuples); (note that the underlying logical represenation is still
   895 bogus);
   896 
   897 
   898 *** ZF ***
   899 
   900 * ZF: simplification automatically cancels common terms in arithmetic
   901 expressions over nat and int;
   902 
   903 * ZF: new treatment of nat to minimize type-checking: all operators
   904 coerce their operands to a natural number using the function natify,
   905 making the algebraic laws unconditional;
   906 
   907 * ZF: as above, for int: operators coerce their operands to an integer
   908 using the function intify;
   909 
   910 * ZF: the integer library now contains many of the usual laws for the
   911 orderings, including $<=, and monotonicity laws for $+ and $*;
   912 
   913 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   914 simplification;
   915 
   916 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   917 to the simplifier and classical reasoner simultaneously;
   918 
   919 
   920 *** General ***
   921 
   922 * Provers: blast_tac now handles actual object-logic rules as
   923 assumptions; note that auto_tac uses blast_tac internally as well;
   924 
   925 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   926 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   927 
   928 * Provers: delrules now handles destruct rules as well (no longer need
   929 explicit make_elim);
   930 
   931 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   932   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   933 use instead the strong form,
   934   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   935 in HOL, FOL and ZF the function cla_make_elim will create such rules
   936 from destruct-rules;
   937 
   938 * Provers: Simplifier.easy_setup provides a fast path to basic
   939 Simplifier setup for new object-logics;
   940 
   941 * Pure: AST translation rules no longer require constant head on LHS;
   942 
   943 * Pure: improved name spaces: ambiguous output is qualified; support
   944 for hiding of names;
   945 
   946 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   947 XSYMBOL_HOME; no longer need to do manual configuration in most
   948 situations;
   949 
   950 * system: compression of ML heaps images may now be controlled via -c
   951 option of isabelle and isatool usedir (currently only observed by
   952 Poly/ML);
   953 
   954 * system: isatool installfonts may handle X-Symbol fonts as well (very
   955 useful for remote X11);
   956 
   957 * system: provide TAGS file for Isabelle sources;
   958 
   959 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   960 order;
   961 
   962 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   963 timing flag supersedes proof_timing and Toplevel.trace;
   964 
   965 * ML: new combinators |>> and |>>> for incremental transformations
   966 with secondary results (e.g. certain theory extensions):
   967 
   968 * ML: PureThy.add_defs gets additional argument to indicate potential
   969 overloading (usually false);
   970 
   971 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   972 results;
   973 
   974 
   975 
   976 New in Isabelle99 (October 1999)
   977 --------------------------------
   978 
   979 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   980 
   981 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   982 are no longer simplified.  (This allows the simplifier to unfold recursive
   983 functional programs.)  To restore the old behaviour, declare
   984 
   985     Delcongs [if_weak_cong];
   986 
   987 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   988 complement;
   989 
   990 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   991 
   992 * HOL/datatype: mutual_induct_tac no longer exists --
   993   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   994 
   995 * HOL/typedef: fixed type inference for representing set; type
   996 arguments now have to occur explicitly on the rhs as type constraints;
   997 
   998 * ZF: The con_defs part of an inductive definition may no longer refer
   999 to constants declared in the same theory;
  1000 
  1001 * HOL, ZF: the function mk_cases, generated by the inductive
  1002 definition package, has lost an argument.  To simplify its result, it
  1003 uses the default simpset instead of a supplied list of theorems.
  1004 
  1005 * HOL/List: the constructors of type list are now Nil and Cons;
  1006 
  1007 * Simplifier: the type of the infix ML functions
  1008         setSSolver addSSolver setSolver addSolver
  1009 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1010 for packaging solvers. A solver is created via
  1011         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1012 where the string argument is only a comment.
  1013 
  1014 
  1015 *** Proof tools ***
  1016 
  1017 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1018 decision procedure for linear arithmetic. Currently it is used for
  1019 types `nat', `int', and `real' in HOL (see below); it can, should and
  1020 will be instantiated for other types and logics as well.
  1021 
  1022 * The simplifier now accepts rewrite rules with flexible heads, eg
  1023      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1024   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1025   matching.
  1026 
  1027 
  1028 *** General ***
  1029 
  1030 * New Isabelle/Isar subsystem provides an alternative to traditional
  1031 tactical theorem proving; together with the ProofGeneral/isar user
  1032 interface it offers an interactive environment for developing human
  1033 readable proof documents (Isar == Intelligible semi-automated
  1034 reasoning); for further information see isatool doc isar-ref,
  1035 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1036 
  1037 * improved and simplified presentation of theories: better HTML markup
  1038 (including colors), graph views in several sizes; isatool usedir now
  1039 provides a proper interface for user theories (via -P option); actual
  1040 document preparation based on (PDF)LaTeX is available as well (for
  1041 new-style theories only); see isatool doc system for more information;
  1042 
  1043 * native support for Proof General, both for classic Isabelle and
  1044 Isabelle/Isar;
  1045 
  1046 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1047 using the graph browser tool;
  1048 
  1049 * Isabelle manuals now also available as PDF;
  1050 
  1051 * theory loader rewritten from scratch (may not be fully
  1052 bug-compatible); old loadpath variable has been replaced by show_path,
  1053 add_path, del_path, reset_path functions; new operations such as
  1054 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1055 isatool doc ref);
  1056 
  1057 * improved isatool install: option -k creates KDE application icon,
  1058 option -p DIR installs standalone binaries;
  1059 
  1060 * added ML_PLATFORM setting (useful for cross-platform installations);
  1061 more robust handling of platform specific ML images for SML/NJ;
  1062 
  1063 * the settings environment is now statically scoped, i.e. it is never
  1064 created again in sub-processes invoked from isabelle, isatool, or
  1065 Isabelle;
  1066 
  1067 * path element specification '~~' refers to '$ISABELLE_HOME';
  1068 
  1069 * in locales, the "assumes" and "defines" parts may be omitted if
  1070 empty;
  1071 
  1072 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1073 long arrows);
  1074 
  1075 * new print_mode "HTML";
  1076 
  1077 * new flag show_tags controls display of tags of theorems (which are
  1078 basically just comments that may be attached by some tools);
  1079 
  1080 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1081 mode and goal output format:
  1082 
  1083 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1084 244c244
  1085 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1086 ---
  1087 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1088 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1089 181c181
  1090 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1091 ---
  1092 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1093 
  1094 * function bind_thms stores lists of theorems (cf. bind_thm);
  1095 
  1096 * new shorthand tactics ftac, eatac, datac, fatac;
  1097 
  1098 * qed (and friends) now accept "" as result name; in that case the
  1099 theorem is not stored, but proper checks and presentation of the
  1100 result still apply;
  1101 
  1102 * theorem database now also indexes constants "Trueprop", "all",
  1103 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1104 
  1105 
  1106 *** HOL ***
  1107 
  1108 ** HOL arithmetic **
  1109 
  1110 * There are now decision procedures for linear arithmetic over nat and
  1111 int:
  1112 
  1113 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1114 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1115 are treated as atomic; subformulae not involving type `nat' or `int'
  1116 are ignored; quantified subformulae are ignored unless they are
  1117 positive universal or negative existential. The tactic has to be
  1118 invoked by hand and can be a little bit slow. In particular, the
  1119 running time is exponential in the number of occurrences of `min' and
  1120 `max', and `-' on `nat'.
  1121 
  1122 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1123 (negated) (in)equalities among the premises and the conclusion into
  1124 account (i.e. no compound formulae) and does not know about `min' and
  1125 `max', and `-' on `nat'. It is fast and is used automatically by the
  1126 simplifier.
  1127 
  1128 NB: At the moment, these decision procedures do not cope with mixed
  1129 nat/int formulae where the two parts interact, such as `m < n ==>
  1130 int(m) < int(n)'.
  1131 
  1132 * HOL/Numeral provides a generic theory of numerals (encoded
  1133 efficiently as bit strings); setup for types nat/int/real is in place;
  1134 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1135 int, existing theories and proof scripts may require a few additional
  1136 type constraints;
  1137 
  1138 * integer division and remainder can now be performed on constant
  1139 arguments;
  1140 
  1141 * many properties of integer multiplication, division and remainder
  1142 are now available;
  1143 
  1144 * An interface to the Stanford Validity Checker (SVC) is available through the
  1145 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1146 are proved automatically.  SVC must be installed separately, and its results
  1147 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1148 invocation of the underlying oracle).  For SVC see
  1149   http://verify.stanford.edu/SVC
  1150 
  1151 * IsaMakefile: the HOL-Real target now builds an actual image;
  1152 
  1153 
  1154 ** HOL misc **
  1155 
  1156 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1157 (in Isabelle/Isar) -- by Gertrud Bauer;
  1158 
  1159 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1160 analysis for assembly languages with subtypes;
  1161 
  1162 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1163 -- avoids syntactic ambiguities and treats state, transition, and
  1164 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1165 changed syntax and (many) tactics;
  1166 
  1167 * HOL/inductive: Now also handles more general introduction rules such
  1168   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1169   theorems are now maintained within the theory (maintained via the
  1170   "mono" attribute);
  1171 
  1172 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1173   (using function types) such as
  1174 
  1175   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1176 
  1177 * HOL/record: record_simproc (part of the default simpset) takes care
  1178 of selectors applied to updated records; record_split_tac is no longer
  1179 part of the default claset; update_defs may now be removed from the
  1180 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1181 
  1182   claset_ref () := claset() addSWrapper record_split_wrapper;
  1183   Delsimprocs [record_simproc]
  1184 
  1185 * HOL/typedef: fixed type inference for representing set; type
  1186 arguments now have to occur explicitly on the rhs as type constraints;
  1187 
  1188 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1189 names rather than an ML expression;
  1190 
  1191 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1192 supplied later.  Program schemes can be defined, such as
  1193     "While B C s = (if B s then While B C (C s) else s)"
  1194 where the well-founded relation can be chosen after B and C have been given.
  1195 
  1196 * HOL/List: the constructors of type list are now Nil and Cons;
  1197 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1198 course, ML tools referring to List.list.op # etc. have to be adapted;
  1199 
  1200 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1201 disabled by default; run isabelle with option -m HOL to get back to
  1202 the original Gordon/HOL-style output;
  1203 
  1204 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1205 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1206 
  1207 * HOL basic syntax simplified (more orthogonal): all variants of
  1208 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1209 Eps operator is provided as well: "SOME x. P[x]";
  1210 
  1211 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1212 
  1213 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1214 thus available for user theories;
  1215 
  1216 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1217 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1218 time;
  1219 
  1220 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1221 several times and then mp;
  1222 
  1223 
  1224 *** LK ***
  1225 
  1226 * the notation <<...>> is now available as a notation for sequences of
  1227 formulas;
  1228 
  1229 * the simplifier is now installed
  1230 
  1231 * the axiom system has been generalized (thanks to Soren Heilmann)
  1232 
  1233 * the classical reasoner now has a default rule database
  1234 
  1235 
  1236 *** ZF ***
  1237 
  1238 * new primrec section allows primitive recursive functions to be given
  1239 directly (as in HOL) over datatypes and the natural numbers;
  1240 
  1241 * new tactics induct_tac and exhaust_tac for induction (or case
  1242 analysis) over datatypes and the natural numbers;
  1243 
  1244 * the datatype declaration of type T now defines the recursor T_rec;
  1245 
  1246 * simplification automatically does freeness reasoning for datatype
  1247 constructors;
  1248 
  1249 * automatic type-inference, with AddTCs command to insert new
  1250 type-checking rules;
  1251 
  1252 * datatype introduction rules are now added as Safe Introduction rules
  1253 to the claset;
  1254 
  1255 * the syntax "if P then x else y" is now available in addition to
  1256 if(P,x,y);
  1257 
  1258 
  1259 *** Internal programming interfaces ***
  1260 
  1261 * tuned simplifier trace output; new flag debug_simp;
  1262 
  1263 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1264 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1265 
  1266 * AxClass.axclass_tac lost the theory argument;
  1267 
  1268 * tuned current_goals_markers semantics: begin / end goal avoids
  1269 printing empty lines;
  1270 
  1271 * removed prs and prs_fn hook, which was broken because it did not
  1272 include \n in its semantics, forcing writeln to add one
  1273 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1274 string -> unit if you really want to output text without newline;
  1275 
  1276 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1277 plain output, interface builders may have to enable 'isabelle_font'
  1278 mode to get Isabelle font glyphs as before;
  1279 
  1280 * refined token_translation interface; INCOMPATIBILITY: output length
  1281 now of type real instead of int;
  1282 
  1283 * theory loader actions may be traced via new ThyInfo.add_hook
  1284 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1285 your own database of information attached to *whole* theories -- as
  1286 opposed to intra-theory data slots offered via TheoryDataFun;
  1287 
  1288 * proper handling of dangling sort hypotheses (at last!);
  1289 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1290 extra sort hypotheses that can be witnessed from the type signature;
  1291 the force_strip_shyps flag is gone, any remaining shyps are simply
  1292 left in the theorem (with a warning issued by strip_shyps_warning);
  1293 
  1294 
  1295 
  1296 New in Isabelle98-1 (October 1998)
  1297 ----------------------------------
  1298 
  1299 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1300 
  1301 * several changes of automated proof tools;
  1302 
  1303 * HOL: major changes to the inductive and datatype packages, including
  1304 some minor incompatibilities of theory syntax;
  1305 
  1306 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1307 called `inj_on';
  1308 
  1309 * HOL: removed duplicate thms in Arith:
  1310   less_imp_add_less  should be replaced by  trans_less_add1
  1311   le_imp_add_le      should be replaced by  trans_le_add1
  1312 
  1313 * HOL: unary minus is now overloaded (new type constraints may be
  1314 required);
  1315 
  1316 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1317 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1318 now taken as an integer constant.
  1319 
  1320 * Pure: ML function 'theory_of' renamed to 'theory';
  1321 
  1322 
  1323 *** Proof tools ***
  1324 
  1325 * Simplifier:
  1326   1. Asm_full_simp_tac is now more aggressive.
  1327      1. It will sometimes reorient premises if that increases their power to
  1328         simplify.
  1329      2. It does no longer proceed strictly from left to right but may also
  1330         rotate premises to achieve further simplification.
  1331      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1332      old Asm_full_simp_tac in that it does not rotate premises.
  1333   2. The simplifier now knows a little bit about nat-arithmetic.
  1334 
  1335 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1336 allows for selected deletion of wrappers, by introduction of names for
  1337 wrapper functionals.  This implies that addbefore, addSbefore,
  1338 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1339 and that adding two tactics with the same name overwrites the first
  1340 one (emitting a warning).
  1341   type wrapper = (int -> tactic) -> (int -> tactic)
  1342   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1343   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1344   delWrapper, delSWrapper: claset *  string            -> claset
  1345   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1346 
  1347 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1348 semantics; addbefore now affects only the unsafe part of step_tac
  1349 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1350 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1351 by Force_tac;
  1352 
  1353 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1354 compWrapper; added safe wrapper (and access functions for it);
  1355 
  1356 * HOL/split_all_tac is now much faster and fails if there is nothing
  1357 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1358 and the names of the automatically generated variables have changed.
  1359 split_all_tac has moved within claset() from unsafe wrappers to safe
  1360 wrappers, which means that !!-bound variables are split much more
  1361 aggressively, and safe_tac and clarify_tac now split such variables.
  1362 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1363 Note: the same holds for record_split_tac, which does the job of
  1364 split_all_tac for record fields.
  1365 
  1366 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1367 permanently to the default simpset using Addsplits just like
  1368 Addsimps. They can be removed via Delsplits just like
  1369 Delsimps. Lower-case versions are also available.
  1370 
  1371 * HOL/Simplifier: The rule split_if is now part of the default
  1372 simpset. This means that the simplifier will eliminate all occurrences
  1373 of if-then-else in the conclusion of a goal. To prevent this, you can
  1374 either remove split_if completely from the default simpset by
  1375 `Delsplits [split_if]' or remove it in a specific call of the
  1376 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1377 other case splitting rules to/from the default simpset: every datatype
  1378 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1379 t is the name of the datatype).
  1380 
  1381 * Classical reasoner / Simplifier combination: new force_tac (and
  1382 derivatives Force_tac, force) combines rewriting and classical
  1383 reasoning (and whatever other tools) similarly to auto_tac, but is
  1384 aimed to solve the given subgoal completely.
  1385 
  1386 
  1387 *** General ***
  1388 
  1389 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1390 and `goalw': the theory is no longer needed as an explicit argument -
  1391 the current theory context is used; assumptions are no longer returned
  1392 at the ML-level unless one of them starts with ==> or !!; it is
  1393 recommended to convert to these new commands using isatool fixgoal
  1394 (backup your sources first!);
  1395 
  1396 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1397 the current theory context, and 'theory' to lookup stored theories;
  1398 
  1399 * new theory section 'locale' for declaring constants, assumptions and
  1400 definitions that have local scope;
  1401 
  1402 * new theory section 'nonterminals' for purely syntactic types;
  1403 
  1404 * new theory section 'setup' for generic ML setup functions
  1405 (e.g. package initialization);
  1406 
  1407 * the distribution now includes Isabelle icons: see
  1408 lib/logo/isabelle-{small,tiny}.xpm;
  1409 
  1410 * isatool install - install binaries with absolute references to
  1411 ISABELLE_HOME/bin;
  1412 
  1413 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1414 
  1415 * print mode 'emacs' reserved for Isamode;
  1416 
  1417 * support multiple print (ast) translations per constant name;
  1418 
  1419 * theorems involving oracles are now printed with a suffixed [!];
  1420 
  1421 
  1422 *** HOL ***
  1423 
  1424 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1425 
  1426 * HOL/inductive package reorganized and improved: now supports mutual
  1427 definitions such as
  1428 
  1429   inductive EVEN ODD
  1430     intrs
  1431       null "0 : EVEN"
  1432       oddI "n : EVEN ==> Suc n : ODD"
  1433       evenI "n : ODD ==> Suc n : EVEN"
  1434 
  1435 new theorem list "elims" contains an elimination rule for each of the
  1436 recursive sets; inductive definitions now handle disjunctive premises
  1437 correctly (also ZF);
  1438 
  1439 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1440 "mutual_induct" no longer exists - the induction rule is always
  1441 contained in "induct";
  1442 
  1443 
  1444 * HOL/datatype package re-implemented and greatly improved: now
  1445 supports mutually recursive datatypes such as
  1446 
  1447   datatype
  1448     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1449             | SUM ('a aexp) ('a aexp)
  1450             | DIFF ('a aexp) ('a aexp)
  1451             | NUM 'a
  1452   and
  1453     'a bexp = LESS ('a aexp) ('a aexp)
  1454             | AND ('a bexp) ('a bexp)
  1455             | OR ('a bexp) ('a bexp)
  1456 
  1457 as well as indirectly recursive datatypes such as
  1458 
  1459   datatype
  1460     ('a, 'b) term = Var 'a
  1461                   | App 'b ((('a, 'b) term) list)
  1462 
  1463 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1464 induction on mutually / indirectly recursive datatypes.
  1465 
  1466 Primrec equations are now stored in theory and can be accessed via
  1467 <function_name>.simps.
  1468 
  1469 INCOMPATIBILITIES:
  1470 
  1471   - Theories using datatypes must now have theory Datatype as an
  1472     ancestor.
  1473   - The specific <typename>.induct_tac no longer exists - use the
  1474     generic induct_tac instead.
  1475   - natE has been renamed to nat.exhaust - use exhaust_tac
  1476     instead of res_inst_tac ... natE. Note that the variable
  1477     names in nat.exhaust differ from the names in natE, this
  1478     may cause some "fragile" proofs to fail.
  1479   - The theorems split_<typename>_case and split_<typename>_case_asm
  1480     have been renamed to <typename>.split and <typename>.split_asm.
  1481   - Since default sorts of type variables are now handled correctly,
  1482     some datatype definitions may have to be annotated with explicit
  1483     sort constraints.
  1484   - Primrec definitions no longer require function name and type
  1485     of recursive argument.
  1486 
  1487 Consider using isatool fixdatatype to adapt your theories and proof
  1488 scripts to the new package (backup your sources first!).
  1489 
  1490 
  1491 * HOL/record package: considerably improved implementation; now
  1492 includes concrete syntax for record types, terms, updates; theorems
  1493 for surjective pairing and splitting !!-bound record variables; proof
  1494 support is as follows:
  1495 
  1496   1) standard conversions (selectors or updates applied to record
  1497 constructor terms) are part of the standard simpset;
  1498 
  1499   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1500 made part of standard simpset and claset via addIffs;
  1501 
  1502   3) a tactic for record field splitting (record_split_tac) is part of
  1503 the standard claset (addSWrapper);
  1504 
  1505 To get a better idea about these rules you may retrieve them via
  1506 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1507 the name of your record type.
  1508 
  1509 The split tactic 3) conceptually simplifies by the following rule:
  1510 
  1511   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1512 
  1513 Thus any record variable that is bound by meta-all will automatically
  1514 blow up into some record constructor term, consequently the
  1515 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1516 solve record problems automatically.
  1517 
  1518 
  1519 * reorganized the main HOL image: HOL/Integ and String loaded by
  1520 default; theory Main includes everything;
  1521 
  1522 * automatic simplification of integer sums and comparisons, using cancellation;
  1523 
  1524 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1525 
  1526 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1527 
  1528 * many new identities for unions, intersections, set difference, etc.;
  1529 
  1530 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1531 called split_if, split_split, split_sum_case and split_nat_case (to go
  1532 with add/delsplits);
  1533 
  1534 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1535 (?x::unit) = (); this is made part of the default simpset, which COULD
  1536 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1537 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1538 unit_abs_eta_conv is added in order to counter the effect of
  1539 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1540 %u.f();
  1541 
  1542 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1543 makes more sense);
  1544 
  1545 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1546   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1547   disjointness reasoning but breaking a few old proofs.
  1548 
  1549 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1550 to 'converse' from 'inverse' (for compatibility with ZF and some
  1551 literature);
  1552 
  1553 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1554 the well-founded relation;
  1555 
  1556 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1557     Compl A.  The "Compl" syntax remains available as input syntax for this
  1558     release ONLY.
  1559 
  1560 * HOL/Update: new theory of function updates:
  1561     f(a:=b) == %x. if x=a then b else f x
  1562 may also be iterated as in f(a:=b,c:=d,...);
  1563 
  1564 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1565 
  1566 * HOL/List:
  1567   - new function list_update written xs[i:=v] that updates the i-th
  1568     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1569   - new function `upt' written [i..j(] which generates the list
  1570     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1571     bound write [i..j], which is a shorthand for [i..j+1(].
  1572   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1573 
  1574 * HOL/Arith:
  1575   - removed 'pred' (predecessor) function;
  1576   - generalized some theorems about n-1;
  1577   - many new laws about "div" and "mod";
  1578   - new laws about greatest common divisors (see theory ex/Primes);
  1579 
  1580 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1581 instead of "inverse";
  1582 
  1583 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1584   of the multiset ordering;
  1585 
  1586 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1587   (not included by default);
  1588 
  1589 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1590 
  1591 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1592   programs, i.e. different program variables may have different types.
  1593 
  1594 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1595   [previously, this check worked only if the rewrite rule was unconditional]
  1596   Now rew can involve either definitions or equalities (either == or =).
  1597 
  1598 
  1599 *** ZF ***
  1600 
  1601 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1602   only the theorems proved on ZF.ML;
  1603 
  1604 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1605   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1606   disjointness reasoning but breaking a few old proofs.
  1607 
  1608 * ZF/Update: new theory of function updates
  1609     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1610   may also be iterated as in f(a:=b,c:=d,...);
  1611 
  1612 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1613 
  1614 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1615   [previously, this check worked only if the rewrite rule was unconditional]
  1616   Now rew can involve either definitions or equalities (either == or =).
  1617 
  1618 * case_tac provided for compatibility with HOL
  1619     (like the old excluded_middle_tac, but with subgoals swapped)
  1620 
  1621 
  1622 *** Internal programming interfaces ***
  1623 
  1624 * Pure: several new basic modules made available for general use, see
  1625 also src/Pure/README;
  1626 
  1627 * improved the theory data mechanism to support encapsulation (data
  1628 kind name replaced by private Object.kind, acting as authorization
  1629 key); new type-safe user interface via functor TheoryDataFun; generic
  1630 print_data function becomes basically useless;
  1631 
  1632 * removed global_names compatibility flag -- all theory declarations
  1633 are qualified by default;
  1634 
  1635 * module Pure/Syntax now offers quote / antiquote translation
  1636 functions (useful for Hoare logic etc. with implicit dependencies);
  1637 see HOL/ex/Antiquote for an example use;
  1638 
  1639 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1640 cterm -> thm;
  1641 
  1642 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1643 subgoal;
  1644 
  1645 * Display.print_goals function moved to Locale.print_goals;
  1646 
  1647 * standard print function for goals supports current_goals_markers
  1648 variable for marking begin of proof, end of proof, start of goal; the
  1649 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1650 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1651 for example;
  1652 
  1653 
  1654 
  1655 New in Isabelle98 (January 1998)
  1656 --------------------------------
  1657 
  1658 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1659 
  1660 * changed lexical syntax of terms / types: dots made part of long
  1661 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1662 
  1663 * simpset (and claset) reference variable replaced by functions
  1664 simpset / simpset_ref;
  1665 
  1666 * no longer supports theory aliases (via merge) and non-trivial
  1667 implicit merge of thms' signatures;
  1668 
  1669 * most internal names of constants changed due to qualified names;
  1670 
  1671 * changed Pure/Sequence interface (see Pure/seq.ML);
  1672 
  1673 
  1674 *** General Changes ***
  1675 
  1676 * hierachically structured name spaces (for consts, types, axms, thms
  1677 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1678 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1679 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1680 long_names for fully qualified output names; NOTE: ML programs
  1681 (special tactics, packages etc.) referring to internal names may have
  1682 to be adapted to cope with fully qualified names; in case of severe
  1683 backward campatibility problems try setting 'global_names' at compile
  1684 time to have enrything declared within a flat name space; one may also
  1685 fine tune name declarations in theories via the 'global' and 'local'
  1686 section;
  1687 
  1688 * reimplemented the implicit simpset and claset using the new anytype
  1689 data filed in signatures; references simpset:simpset ref etc. are
  1690 replaced by functions simpset:unit->simpset and
  1691 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1692 to patch your ML files accordingly;
  1693 
  1694 * HTML output now includes theory graph data for display with Java
  1695 applet or isatool browser; data generated automatically via isatool
  1696 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1697 
  1698 * defs may now be conditional; improved rewrite_goals_tac to handle
  1699 conditional equations;
  1700 
  1701 * defs now admits additional type arguments, using TYPE('a) syntax;
  1702 
  1703 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1704 creates a new theory node; implicit merge of thms' signatures is
  1705 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1706 transfer:theory->thm->thm in (rare) cases;
  1707 
  1708 * improved handling of draft signatures / theories; draft thms (and
  1709 ctyps, cterms) are automatically promoted to real ones;
  1710 
  1711 * slightly changed interfaces for oracles: admit many per theory, named
  1712 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1713 
  1714 * print_goals: optional output of const types (set show_consts and
  1715 show_types);
  1716 
  1717 * improved output of warnings (###) and errors (***);
  1718 
  1719 * subgoal_tac displays a warning if the new subgoal has type variables;
  1720 
  1721 * removed old README and Makefiles;
  1722 
  1723 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1724 
  1725 * removed obsolete init_pps and init_database;
  1726 
  1727 * deleted the obsolete tactical STATE, which was declared by
  1728     fun STATE tacfun st = tacfun st st;
  1729 
  1730 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1731 (which abbreviates $HOME);
  1732 
  1733 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1734 use isatool fixseq to adapt your ML programs (this works for fully
  1735 qualified references to the Sequence structure only!);
  1736 
  1737 * use_thy no longer requires writable current directory; it always
  1738 reloads .ML *and* .thy file, if either one is out of date;
  1739 
  1740 
  1741 *** Classical Reasoner ***
  1742 
  1743 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1744 tactics that use classical reasoning to simplify a subgoal without
  1745 splitting it into several subgoals;
  1746 
  1747 * Safe_tac: like safe_tac but uses the default claset;
  1748 
  1749 
  1750 *** Simplifier ***
  1751 
  1752 * added simplification meta rules:
  1753     (asm_)(full_)simplify: simpset -> thm -> thm;
  1754 
  1755 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1756 logics (again);
  1757 
  1758 * added prems argument to simplification procedures;
  1759 
  1760 * HOL, FOL, ZF: added infix function `addsplits':
  1761   instead of `<simpset> setloop (split_tac <thms>)'
  1762   you can simply write `<simpset> addsplits <thms>'
  1763 
  1764 
  1765 *** Syntax ***
  1766 
  1767 * TYPE('a) syntax for type reflection terms;
  1768 
  1769 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1770 
  1771 * pretty printer: changed order of mixfix annotation preference (again!);
  1772 
  1773 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1774 
  1775 
  1776 *** HOL ***
  1777 
  1778 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1779   with `addloop' of the simplifier to faciliate case splitting in premises.
  1780 
  1781 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1782 
  1783 * HOL/Auth: new protocol proofs including some for the Internet
  1784   protocol TLS;
  1785 
  1786 * HOL/Map: new theory of `maps' a la VDM;
  1787 
  1788 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1789 cancelling out common nat summands from =, <, <= (in)equalities, or
  1790 differences; simplification procedures nat_cancel_factor for
  1791 cancelling common factor from =, <, <= (in)equalities over natural
  1792 sums; nat_cancel contains both kinds of procedures, it is installed by
  1793 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1794 
  1795 * HOL/simplifier: terms of the form
  1796   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1797   are rewritten to
  1798   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1799   and those of the form
  1800   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1801   are rewritten to
  1802   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1803 
  1804 * HOL/datatype
  1805   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1806 
  1807   P(t_case f1 ... fn x) =
  1808      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1809         ...
  1810        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1811      )
  1812 
  1813   and a theorem `split_t_case_asm' 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   which can be added to a simpset via `addsplits'. The existing theorems
  1821   expand_list_case and expand_option_case have been renamed to
  1822   split_list_case and split_option_case.
  1823 
  1824 * HOL/Arithmetic:
  1825   - `pred n' is automatically converted to `n-1'.
  1826     Users are strongly encouraged not to use `pred' any longer,
  1827     because it will disappear altogether at some point.
  1828   - Users are strongly encouraged to write "0 < n" rather than
  1829     "n ~= 0". Theorems and proof tools have been modified towards this
  1830     `standard'.
  1831 
  1832 * HOL/Lists:
  1833   the function "set_of_list" has been renamed "set" (and its theorems too);
  1834   the function "nth" now takes its arguments in the reverse order and
  1835   has acquired the infix notation "!" as in "xs!n".
  1836 
  1837 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1838 
  1839 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1840   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1841 
  1842 * HOL/record: extensible records with schematic structural subtyping
  1843 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1844 still lacks various theorems and concrete record syntax;
  1845 
  1846 
  1847 *** HOLCF ***
  1848 
  1849 * removed "axioms" and "generated by" sections;
  1850 
  1851 * replaced "ops" section by extended "consts" section, which is capable of
  1852   handling the continuous function space "->" directly;
  1853 
  1854 * domain package:
  1855   . proves theorems immediately and stores them in the theory,
  1856   . creates hierachical name space,
  1857   . now uses normal mixfix annotations (instead of cinfix...),
  1858   . minor changes to some names and values (for consistency),
  1859   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1860   . separator between mutual domain defs: changed "," to "and",
  1861   . improved handling of sort constraints;  now they have to
  1862     appear on the left-hand side of the equations only;
  1863 
  1864 * fixed LAM <x,y,zs>.b syntax;
  1865 
  1866 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1867 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1868 
  1869 
  1870 *** FOL and ZF ***
  1871 
  1872 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1873   with `addloop' of the simplifier to faciliate case splitting in premises.
  1874 
  1875 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1876 in HOL, they strip ALL and --> from proved theorems;
  1877 
  1878 
  1879 
  1880 New in Isabelle94-8 (May 1997)
  1881 ------------------------------
  1882 
  1883 *** General Changes ***
  1884 
  1885 * new utilities to build / run / maintain Isabelle etc. (in parts
  1886 still somewhat experimental); old Makefiles etc. still functional;
  1887 
  1888 * new 'Isabelle System Manual';
  1889 
  1890 * INSTALL text, together with ./configure and ./build scripts;
  1891 
  1892 * reimplemented type inference for greater efficiency, better error
  1893 messages and clean internal interface;
  1894 
  1895 * prlim command for dealing with lots of subgoals (an easier way of
  1896 setting goals_limit);
  1897 
  1898 
  1899 *** Syntax ***
  1900 
  1901 * supports alternative (named) syntax tables (parser and pretty
  1902 printer); internal interface is provided by add_modesyntax(_i);
  1903 
  1904 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1905 be used in conjunction with the Isabelle symbol font; uses the
  1906 "symbols" syntax table;
  1907 
  1908 * added token_translation interface (may translate name tokens in
  1909 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1910 the current print_mode); IMPORTANT: user print translation functions
  1911 are responsible for marking newly introduced bounds
  1912 (Syntax.mark_boundT);
  1913 
  1914 * token translations for modes "xterm" and "xterm_color" that display
  1915 names in bold, underline etc. or colors (which requires a color
  1916 version of xterm);
  1917 
  1918 * infixes may now be declared with names independent of their syntax;
  1919 
  1920 * added typed_print_translation (like print_translation, but may
  1921 access type of constant);
  1922 
  1923 
  1924 *** Classical Reasoner ***
  1925 
  1926 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1927 some limitations.  Blast_tac...
  1928   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1929   + ignores elimination rules that don't have the correct format
  1930         (the conclusion MUST be a formula variable)
  1931   + ignores types, which can make HOL proofs fail
  1932   + rules must not require higher-order unification, e.g. apply_type in ZF
  1933     [message "Function Var's argument not a bound variable" relates to this]
  1934   + its proof strategy is more general but can actually be slower
  1935 
  1936 * substitution with equality assumptions no longer permutes other
  1937 assumptions;
  1938 
  1939 * minor changes in semantics of addafter (now called addaltern); renamed
  1940 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1941 (and access functions for it);
  1942 
  1943 * improved combination of classical reasoner and simplifier:
  1944   + functions for handling clasimpsets
  1945   + improvement of addss: now the simplifier is called _after_ the
  1946     safe steps.
  1947   + safe variant of addss called addSss: uses safe simplifications
  1948     _during_ the safe steps. It is more complete as it allows multiple
  1949     instantiations of unknowns (e.g. with slow_tac).
  1950 
  1951 *** Simplifier ***
  1952 
  1953 * added interface for simplification procedures (functions that
  1954 produce *proven* rewrite rules on the fly, depending on current
  1955 redex);
  1956 
  1957 * ordering on terms as parameter (used for ordered rewriting);
  1958 
  1959 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1960 
  1961 * the solver is now split into a safe and an unsafe part.
  1962 This should be invisible for the normal user, except that the
  1963 functions setsolver and addsolver have been renamed to setSolver and
  1964 addSolver; added safe_asm_full_simp_tac;
  1965 
  1966 
  1967 *** HOL ***
  1968 
  1969 * a generic induction tactic `induct_tac' which works for all datatypes and
  1970 also for type `nat';
  1971 
  1972 * a generic case distinction tactic `exhaust_tac' which works for all
  1973 datatypes and also for type `nat';
  1974 
  1975 * each datatype comes with a function `size';
  1976 
  1977 * patterns in case expressions allow tuple patterns as arguments to
  1978 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1979 
  1980 * primrec now also works with type nat;
  1981 
  1982 * recdef: a new declaration form, allows general recursive functions to be
  1983 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1984 
  1985 * the constant for negation has been renamed from "not" to "Not" to
  1986 harmonize with FOL, ZF, LK, etc.;
  1987 
  1988 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1989 infinite lists;
  1990 
  1991 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1992 
  1993 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1994 problems in commutative rings, using axiomatic type classes for + and *;
  1995 
  1996 * more examples in HOL/MiniML and HOL/Auth;
  1997 
  1998 * more default rewrite rules for quantifiers, union/intersection;
  1999 
  2000 * a new constant `arbitrary == @x.False';
  2001 
  2002 * HOLCF/IOA replaces old HOL/IOA;
  2003 
  2004 * HOLCF changes: derived all rules and arities
  2005   + axiomatic type classes instead of classes
  2006   + typedef instead of faking type definitions
  2007   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2008   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2009   + eliminated the types void, one, tr
  2010   + use unit lift and bool lift (with translations) instead of one and tr
  2011   + eliminated blift from Lift3.thy (use Def instead of blift)
  2012   all eliminated rules are derived as theorems --> no visible changes ;
  2013 
  2014 
  2015 *** ZF ***
  2016 
  2017 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2018 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2019 as ZF_cs addSIs [equalityI];
  2020 
  2021 
  2022 
  2023 New in Isabelle94-7 (November 96)
  2024 ---------------------------------
  2025 
  2026 * allowing negative levels (as offsets) in prlev and choplev;
  2027 
  2028 * super-linear speedup for large simplifications;
  2029 
  2030 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2031 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2032 FAIL); can suppress it using the command Delsimps (ex_simps @
  2033 all_simps); De Morgan laws are also now included, by default;
  2034 
  2035 * improved printing of ==>  :  ~:
  2036 
  2037 * new object-logic "Sequents" adds linear logic, while replacing LK
  2038 and Modal (thanks to Sara Kalvala);
  2039 
  2040 * HOL/Auth: correctness proofs for authentication protocols;
  2041 
  2042 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2043 examples on HOL/Auth);
  2044 
  2045 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2046 the rewriter and classical reasoner simultaneously;
  2047 
  2048 * function uresult no longer returns theorems in "standard" format;
  2049 regain previous version by: val uresult = standard o uresult;
  2050 
  2051 
  2052 
  2053 New in Isabelle94-6
  2054 -------------------
  2055 
  2056 * oracles -- these establish an interface between Isabelle and trusted
  2057 external reasoners, which may deliver results as theorems;
  2058 
  2059 * proof objects (in particular record all uses of oracles);
  2060 
  2061 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2062 
  2063 * "constdefs" section in theory files;
  2064 
  2065 * "primrec" section (HOL) no longer requires names;
  2066 
  2067 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2068 
  2069 
  2070 
  2071 New in Isabelle94-5
  2072 -------------------
  2073 
  2074 * reduced space requirements;
  2075 
  2076 * automatic HTML generation from theories;
  2077 
  2078 * theory files no longer require "..." (quotes) around most types;
  2079 
  2080 * new examples, including two proofs of the Church-Rosser theorem;
  2081 
  2082 * non-curried (1994) version of HOL is no longer distributed;
  2083 
  2084 
  2085 
  2086 New in Isabelle94-4
  2087 -------------------
  2088 
  2089 * greatly reduced space requirements;
  2090 
  2091 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2092 
  2093 * searchable theorem database (see the section "Retrieving theorems" on
  2094 page 8 of the Reference Manual);
  2095 
  2096 * new examples, including Grabczewski's monumental case study of the
  2097 Axiom of Choice;
  2098 
  2099 * The previous version of HOL renamed to Old_HOL;
  2100 
  2101 * The new version of HOL (previously called CHOL) uses a curried syntax
  2102 for functions.  Application looks like f a b instead of f(a,b);
  2103 
  2104 * Mutually recursive inductive definitions finally work in HOL;
  2105 
  2106 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2107 translates to the operator "split";
  2108 
  2109 
  2110 
  2111 New in Isabelle94-3
  2112 -------------------
  2113 
  2114 * new infix operator, addss, allowing the classical reasoner to
  2115 perform simplification at each step of its search.  Example:
  2116         fast_tac (cs addss ss)
  2117 
  2118 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2119 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2120 look like (a,b) instead of <a,b>;
  2121 
  2122 * PLEASE NOTE: CHOL will eventually replace HOL!
  2123 
  2124 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2125 It translates to the operator "split".  A new theory of integers is available;
  2126 
  2127 * In ZF, integer numerals now denote two's-complement binary integers.
  2128 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2129 
  2130 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2131 of the Axiom of Choice;
  2132 
  2133 
  2134 
  2135 New in Isabelle94-2
  2136 -------------------
  2137 
  2138 * Significantly faster resolution;
  2139 
  2140 * the different sections in a .thy file can now be mixed and repeated
  2141 freely;
  2142 
  2143 * Database of theorems for FOL, HOL and ZF.  New
  2144 commands including qed, qed_goal and bind_thm store theorems in the database.
  2145 
  2146 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2147 a given theory (thms_of), or find out what theory a theorem was proved in
  2148 (theory_of_thm);
  2149 
  2150 * Bugs fixed in the inductive definition and datatype packages;
  2151 
  2152 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2153 and HOL_dup_cs obsolete;
  2154 
  2155 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2156 have been removed;
  2157 
  2158 * Simpler definition of function space in ZF;
  2159 
  2160 * new results about cardinal and ordinal arithmetic in ZF;
  2161 
  2162 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2163 types;
  2164 
  2165 
  2166 $Id$