NEWS
author wenzelm
Mon Jan 14 17:45:30 2002 +0100 (2002-01-14)
changeset 12753 3a62df7ae926
parent 12736 80f10551fb59
child 12754 044a59921f3b
permissions -rw-r--r--
* system: reduced base memory usage by Poly/ML (approx. 20 MB instead
of 40 MB), cf. ML_OPTIONS;
     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; added \<euro> symbol;
    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   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    64   - moved induct/cases attributes to Pure, methods to Provers;
    65   - generic method setup instantiated for FOL and HOL;
    66 
    67 * Pure: support multiple simultaneous goal statements, for example
    68 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    69 meta-level mechanism, this acts as if several individual goals had
    70 been stated separately; in particular common proof methods need to be
    71 repeated in order to cover all claims; note that a single elimination
    72 step is *not* sufficient to establish the two conjunctions, so this
    73 fails:
    74 
    75   assume "A & B" then have A and B ..   (*".." fails*)
    76 
    77 better use "obtain" in situations as above; alternative refer to
    78 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    79 
    80 * Pure: proper integration with ``locales''; unlike the original
    81 version by Florian Kammüller, Isar locales package high-level proof
    82 contexts rather than raw logical ones (e.g. we admit to include
    83 attributes everywhere); operations on locales include merge and
    84 rename; e.g. see HOL/ex/Locales.thy;
    85 
    86 * Pure: the following commands have been ``localized'', supporting a
    87 target locale specification "(in name)": 'lemma', 'theorem',
    88 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
    89 stored both within the locale and at the theory level (exported and
    90 qualified by the locale name);
    91 
    92 * Pure: theory goals now support ad-hoc contexts, which are discharged
    93 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    94 coincides with that of a locale body;
    95 
    96 * Pure: renamed "antecedent" case to "rule_context";
    97 
    98 * Pure: added 'corollary' command;
    99 
   100 * Pure: fixed 'token_translation' command;
   101 
   102 * Pure: removed obsolete 'exported' attribute;
   103 
   104 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   105 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   106 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   107 
   108 * Pure: method 'atomize' presents local goal premises as object-level
   109 statements (atomic meta-level propositions); setup controlled via
   110 rewrite rules declarations of 'atomize' attribute; example
   111 application: 'induct' method with proper rule statements in improper
   112 proof *scripts*;
   113 
   114 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   115 now consider the syntactic context of assumptions, giving a better
   116 chance to get type-inference of the arguments right (this is
   117 especially important for locales);
   118 
   119 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   120 mode;
   121 
   122 * Pure/obtain: the formal conclusion "thesis", being marked as
   123 ``internal'', may no longer be reference directly in the text;
   124 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   125 situations;
   126 
   127 * Pure: generic 'sym' attribute which declares a rule both as pure
   128 'elim?' and for the 'symmetric' operation;
   129 
   130 * Pure/Provers/classical: simplified integration with pure rule
   131 attributes and methods; the classical "intro?/elim?/dest?"
   132 declarations coincide with the pure ones; the "rule" method no longer
   133 includes classically swapped intros; "intro" and "elim" methods no
   134 longer pick rules from the context; also got rid of ML declarations
   135 AddXIs/AddXEs/AddXDs; all of this has some potential for
   136 INCOMPATIBILITY;
   137 
   138 * Provers/classical: attribute 'swapped' produces classical inversions
   139 of introduction rules;
   140 
   141 * Provers/simplifier: 'simplified' attribute may refer to explicit
   142 rules instead of full simplifier context; 'iff' attribute handles
   143 conditional rules;
   144 
   145 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   146 
   147 * HOL: 'recdef' now fails on unfinished automated proofs, use
   148 "(permissive)" option to recover old behavior;
   149 
   150 * HOL: 'inductive' no longer features separate (collective) attributes
   151 for 'intros' (was found too confusing);
   152 
   153 * HOL: properly declared induction rules less_induct and
   154 wf_induct_rule;
   155 
   156 
   157 *** HOL ***
   158 
   159 * HOL: moved over to sane numeral syntax; the new policy is as
   160 follows:
   161 
   162   - 0 and 1 are polymorphic constants, which are defined on any
   163   numeric type (nat, int, real etc.);
   164 
   165   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   166   binary representation internally;
   167 
   168   - type nat has special constructor Suc, and generally prefers Suc 0
   169   over 1::nat and Suc (Suc 0) over 2::nat;
   170 
   171 This change may cause significant problems of INCOMPATIBILITY; here
   172 are some hints on converting existing sources:
   173 
   174   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   175   entities, so expressions involving "-" (unary or binary minus) need
   176   to be spaced properly;
   177 
   178   - existing occurrences of "1" may need to be constraint "1::nat" or
   179   even replaced by Suc 0; similar for old "2";
   180 
   181   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   182 
   183   - remove all special provisions on numerals in proofs;
   184 
   185 * HOL: symbolic syntax for x^2 (numeral 2);
   186 
   187 * HOL: the class of all HOL types is now called "type" rather than
   188 "term"; INCOMPATIBILITY, need to adapt references to this type class
   189 in axclass/classes, instance/arities, and (usually rare) occurrences
   190 in typings (of consts etc.); internally the class is called
   191 "HOL.type", ML programs should refer to HOLogic.typeS;
   192 
   193 * HOL/record package improvements:
   194   - new derived operations "fields" to build a partial record section,
   195     "extend" to promote a fixed record to a record scheme, and
   196     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   197     declared as simp by default;
   198   - shared operations ("more", "fields", etc.) now need to be always
   199     qualified) --- potential INCOMPATIBILITY;
   200   - removed "make_scheme" operations (use "make" with "extend") --
   201     INCOMPATIBILITY;
   202   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   203   - provides cases/induct rules for use with corresponding Isar
   204     methods (for concrete records, record schemes, concrete more
   205     parts, and schematic more parts -- in that order);
   206   - internal definitions directly based on a light-weight abstract
   207     theory of product types over typedef rather than datatype;
   208 
   209 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   210 
   211 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   212 (beware of argument permutation!);
   213 
   214 * HOL: linorder_less_split superseded by linorder_cases;
   215 
   216 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   217 to peripheral theory "Hilbert_Choice";
   218 
   219 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   220 in this (rare) case use:
   221 
   222   delSWrapper "split_all_tac"
   223   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   224 
   225 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   226 MAY FAIL;
   227 
   228 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   229 Isabelle's type classes, ^ on functions and relations has too general
   230 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   231 necessary to attach explicit type constraints;
   232 
   233 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   234 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   235 (eg "compI" -> "rel_compI").
   236 
   237 * HOL: syntax translations now work properly with numerals and records
   238 expressions;
   239 
   240 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   241 of "lam" -- INCOMPATIBILITY;
   242 
   243 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   244 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   245 renamed "Product_Type.unit";
   246 
   247 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   248 
   249 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   250 Florian Kammüller);
   251 
   252 * HOL/IMP: updated and converted to new-style theory format; several
   253 parts turned into readable document, with proper Isar proof texts and
   254 some explanations (by Gerwin Klein);
   255 
   256 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   257 
   258 * HOL-Hyperreal is now a logic image;
   259 
   260 
   261 *** HOLCF ***
   262 
   263 * Isar: consts/constdefs supports mixfix syntax for continuous
   264 operations;
   265 
   266 * Isar: domain package adapted to new-style theory format, e.g. see
   267 HOLCF/ex/Dnat.thy;
   268 
   269 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   270 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   271 lift.induct_tac, always use UU instead of Undef;
   272 
   273 * HOLCF/IMP: updated and converted to new-style theory;
   274 
   275 
   276 *** ZF ***
   277 
   278 * Isar: proper integration of logic-specific tools and packages,
   279 including theory commands '(co)inductive', '(co)datatype',
   280 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   281 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   282 
   283 * theory Main no longer includes AC; for the Axiom of Choice, base
   284 your theory on Main_ZFC;
   285 
   286 * the integer library now covers quotients and remainders, with many
   287 laws relating division to addition, multiplication, etc.;
   288 
   289 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   290 typeless version of the formalism;
   291 
   292 * ZF/IMP: updated and converted to new-style theory format;
   293 
   294 * ZF/Induct: new directory for examples of inductive definitions,
   295 including theory Multiset for multiset orderings; converted to
   296 new-style theory format;
   297 
   298 
   299 *** General ***
   300 
   301 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   302 variable proof controls level of detail: 0 = no proofs (only oracle
   303 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   304 also ref manual for further ML interfaces;
   305 
   306 * Pure/axclass: removed obsolete ML interface
   307 goal_subclass/goal_arity;
   308 
   309 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   310 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   311 separate tokens, so expressions involving minus need to be spaced
   312 properly;
   313 
   314 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   315 rather than "infixl" or "infixr";
   316 
   317 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   318 sort constraint specifications in type inference; e.g. "x::_::foo"
   319 ensures that the type of "x" is of sort "foo" (but not necessarily a
   320 type variable);
   321 
   322 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   323 control output of nested => (types); the default behavior is
   324 "type_brackets";
   325 
   326 * Pure/syntax: builtin parse translation for "_constify" turns valued
   327 tokens into AST constants;
   328 
   329 * Pure/syntax: prefer later declarations of translations and print
   330 translation functions; potential INCOMPATIBILITY: need to reverse
   331 multiple declarations for same syntax element constant;
   332 
   333 * Provers/classical: renamed addaltern to addafter, addSaltern to
   334 addSafter;
   335 
   336 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   337 as well;
   338 
   339 * system: tested support for MacOS X; should be able to get Isabelle +
   340 Proof General to work in a plain Terminal after installing Poly/ML
   341 (e.g. from the Isabelle distribution area) and GNU bash alone
   342 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   343 support requires further installations, e.g. from
   344 http://fink.sourceforge.net/);
   345 
   346 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   347 
   348 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   349 of 40 MB), cf. ML_OPTIONS;
   350 
   351 * system: Proof General keywords specification is now part of the
   352 Isabelle distribution (see etc/isar-keywords.el);
   353 
   354 * system: support for persistent Proof General sessions (refrain from
   355 outdating all loaded theories on startup); user may create writable
   356 logic images like this: ``isabelle -q HOL Test'';
   357 
   358 * system: smart selection of Isabelle process versus Isabelle
   359 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   360 run both "isabelle" and "Isabelle" even if file names are badly
   361 damaged (executable inspects the case of the first letter of its own
   362 name); added separate "isabelle-process" and "isabelle-interface";
   363 
   364 * system: refrain from any attempt at filtering input streams; no
   365 longer support ``8bit'' encoding of old isabelle font, instead proper
   366 iso-latin characters may now be used; the related isatools
   367 "symbolinput" and "nonascii" have disappeared as well;
   368 
   369 * system: removed old "xterm" interface (the print modes "xterm" and
   370 "xterm_color" are still available for direct use in a suitable
   371 terminal);
   372 
   373 
   374 
   375 New in Isabelle99-2 (February 2001)
   376 -----------------------------------
   377 
   378 *** Overview of INCOMPATIBILITIES ***
   379 
   380 * HOL: please note that theories in the Library and elsewhere often use the
   381 new-style (Isar) format; to refer to their theorems in an ML script you must
   382 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   383 
   384 * HOL: inductive package no longer splits induction rule aggressively,
   385 but only as far as specified by the introductions given; the old
   386 format may be recovered via ML function complete_split_rule or attribute
   387 'split_rule (complete)';
   388 
   389 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   390 gfp_Tarski to gfp_unfold;
   391 
   392 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   393 
   394 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   395 relation); infix "^^" has been renamed "``"; infix "``" has been
   396 renamed "`"; "univalent" has been renamed "single_valued";
   397 
   398 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   399 operation;
   400 
   401 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   402 
   403 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   404 
   405 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   406 consequence, it is no longer monotonic wrt. the local goal context
   407 (which is now passed through the inductive cases);
   408 
   409 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   410 \<gg> to \<ggreater>;
   411 
   412 
   413 *** Document preparation ***
   414 
   415 * \isabellestyle{NAME} selects version of Isabelle output (currently
   416 available: are "it" for near math-mode best-style output, "sl" for
   417 slanted text style, and "tt" for plain type-writer; if no
   418 \isabellestyle command is given, output is according to slanted
   419 type-writer);
   420 
   421 * support sub/super scripts (for single symbols only), input syntax is
   422 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   423 
   424 * some more standard symbols; see Appendix A of the system manual for
   425 the complete list of symbols defined in isabellesym.sty;
   426 
   427 * improved isabelle style files; more abstract symbol implementation
   428 (should now use \isamath{...} and \isatext{...} in custom symbol
   429 definitions);
   430 
   431 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   432 state; Note that presentation of goal states does not conform to
   433 actual human-readable proof documents.  Please do not include goal
   434 states into document output unless you really know what you are doing!
   435 
   436 * proper indentation of antiquoted output with proportional LaTeX
   437 fonts;
   438 
   439 * no_document ML operator temporarily disables LaTeX document
   440 generation;
   441 
   442 * isatool unsymbolize tunes sources for plain ASCII communication;
   443 
   444 
   445 *** Isar ***
   446 
   447 * Pure: Isar now suffers initial goal statements to contain unbound
   448 schematic variables (this does not conform to actual readable proof
   449 documents, due to unpredictable outcome and non-compositional proof
   450 checking); users who know what they are doing may use schematic goals
   451 for Prolog-style synthesis of proven results;
   452 
   453 * Pure: assumption method (an implicit finishing) now handles actual
   454 rules as well;
   455 
   456 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   457 initial goal, declare "that" only as Pure intro (only for single
   458 steps); the "that" rule assumption may now be involved in implicit
   459 finishing, thus ".." becomes a feasible for trivial obtains;
   460 
   461 * Pure: default proof step now includes 'intro_classes'; thus trivial
   462 instance proofs may be performed by "..";
   463 
   464 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   465 statements as well;
   466 
   467 * Pure: more robust selection of calculational rules;
   468 
   469 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   470 rule (as well as the assumption rule);
   471 
   472 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   473 lemmas, using the graph browser tool;
   474 
   475 * Pure: predict failure of "show" in interactive mode;
   476 
   477 * Pure: 'thms_containing' now takes actual terms as arguments;
   478 
   479 * HOL: improved method 'induct' --- now handles non-atomic goals
   480 (potential INCOMPATIBILITY); tuned error handling;
   481 
   482 * HOL: cases and induct rules now provide explicit hints about the
   483 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   484 any remaining facts are inserted into the goal verbatim;
   485 
   486 * HOL: local contexts (aka cases) may now contain term bindings as
   487 well; the 'cases' and 'induct' methods new provide a ?case binding for
   488 the result to be shown in each case;
   489 
   490 * HOL: added 'recdef_tc' command;
   491 
   492 * isatool convert assists in eliminating legacy ML scripts;
   493 
   494 
   495 *** HOL ***
   496 
   497 * HOL/Library: a collection of generic theories to be used together
   498 with main HOL; the theory loader path already includes this directory
   499 by default; the following existing theories have been moved here:
   500 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   501 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   502 
   503 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   504 modelling and verification task performed in Isabelle/HOL +
   505 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   506 
   507 * HOL/Algebra: special summation operator SUM no longer exists, it has
   508 been replaced by setsum; infix 'assoc' now has priority 50 (like
   509 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   510 'domain', this makes the theory consistent with mathematical
   511 literature;
   512 
   513 * HOL basics: added overloaded operations "inverse" and "divide"
   514 (infix "/"), syntax for generic "abs" operation, generic summation
   515 operator \<Sum>;
   516 
   517 * HOL/typedef: simplified package, provide more useful rules (see also
   518 HOL/subset.thy);
   519 
   520 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   521 now expressed as a proper nested rule (old-style tactic scripts may
   522 require atomize_strip_tac to cope with non-atomic premises);
   523 
   524 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   525 to "split_conv" (old name still available for compatibility);
   526 
   527 * HOL: improved concrete syntax for strings (e.g. allows translation
   528 rules with string literals);
   529 
   530 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   531  and Fleuriot's mechanization of analysis, including the transcendental
   532  functions for the reals;
   533 
   534 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   535 
   536 
   537 *** CTT ***
   538 
   539 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   540 "lam" is displayed as TWO lambda-symbols
   541 
   542 * CTT: theory Main now available, containing everything (that is, Bool
   543 and Arith);
   544 
   545 
   546 *** General ***
   547 
   548 * Pure: the Simplifier has been implemented properly as a derived rule
   549 outside of the actual kernel (at last!); the overall performance
   550 penalty in practical applications is about 50%, while reliability of
   551 the Isabelle inference kernel has been greatly improved;
   552 
   553 * print modes "brackets" and "no_brackets" control output of nested =>
   554 (types) and ==> (props); the default behaviour is "brackets";
   555 
   556 * Provers: fast_tac (and friends) now handle actual object-logic rules
   557 as assumptions as well;
   558 
   559 * system: support Poly/ML 4.0;
   560 
   561 * system: isatool install handles KDE version 1 or 2;
   562 
   563 
   564 
   565 New in Isabelle99-1 (October 2000)
   566 ----------------------------------
   567 
   568 *** Overview of INCOMPATIBILITIES ***
   569 
   570 * HOL: simplification of natural numbers is much changed; to partly
   571 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   572 issue the following ML commands:
   573 
   574   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   575   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   576 
   577 * HOL: simplification no longer dives into case-expressions; this is
   578 controlled by "t.weak_case_cong" for each datatype t;
   579 
   580 * HOL: nat_less_induct renamed to less_induct;
   581 
   582 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   583 fixsome to patch .thy and .ML sources automatically;
   584 
   585   select_equality  -> some_equality
   586   select_eq_Ex     -> some_eq_ex
   587   selectI2EX       -> someI2_ex
   588   selectI2         -> someI2
   589   selectI          -> someI
   590   select1_equality -> some1_equality
   591   Eps_sym_eq       -> some_sym_eq_trivial
   592   Eps_eq           -> some_eq_trivial
   593 
   594 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   595 
   596 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   597 instead);
   598 
   599 * HOL: the recursion equations generated by 'recdef' are now called
   600 f.simps instead of f.rules;
   601 
   602 * HOL: qed_spec_mp now also handles bounded ALL as well;
   603 
   604 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   605 sometimes be needed;
   606 
   607 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   608 
   609 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   610 
   611 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   612 product is now "<*>" instead of "Times"; the lexicographic product is
   613 now "<*lex*>" instead of "**";
   614 
   615 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   616 of main HOL, but was unused); better use HOL's datatype package;
   617 
   618 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   619 the old syntax may be recovered as follows:
   620 
   621   syntax (symbols)
   622     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   623       (infixl "\\<oplus>" 100)
   624 
   625 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   626 
   627 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   628 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   629 internally;
   630 
   631 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   632 changed from A/r to A//r;
   633 
   634 * ZF: new treatment of arithmetic (nat & int) may break some old
   635 proofs;
   636 
   637 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   638 rulify -> rule_format, elimify -> elim_format, ...);
   639 
   640 * Isar/Provers: intro/elim/dest attributes changed; renamed
   641 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   642 should have to change intro!! to intro? only); replaced "delrule" by
   643 "rule del";
   644 
   645 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   646 
   647 * Provers: strengthened force_tac by using new first_best_tac;
   648 
   649 * LaTeX document preparation: several changes of isabelle.sty (see
   650 lib/texinputs);
   651 
   652 
   653 *** Document preparation ***
   654 
   655 * formal comments (text blocks etc.) in new-style theories may now
   656 contain antiquotations of thm/prop/term/typ/text to be presented
   657 according to latex print mode; concrete syntax is like this:
   658 @{term[show_types] "f(x) = a + x"};
   659 
   660 * isatool mkdir provides easy setup of Isabelle session directories,
   661 including proper document sources;
   662 
   663 * generated LaTeX sources are now deleted after successful run
   664 (isatool document -c); may retain a copy somewhere else via -D option
   665 of isatool usedir;
   666 
   667 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   668 style files, achieving self-contained LaTeX sources and simplifying
   669 LaTeX debugging;
   670 
   671 * old-style theories now produce (crude) LaTeX output as well;
   672 
   673 * browser info session directories are now self-contained (may be put
   674 on WWW server seperately); improved graphs of nested sessions; removed
   675 graph for 'all sessions';
   676 
   677 * several improvements in isabelle style files; \isabellestyle{it}
   678 produces fake math mode output; \isamarkupheader is now \section by
   679 default; see lib/texinputs/isabelle.sty etc.;
   680 
   681 
   682 *** Isar ***
   683 
   684 * Isar/Pure: local results and corresponding term bindings are now
   685 subject to Hindley-Milner polymorphism (similar to ML); this
   686 accommodates incremental type-inference very nicely;
   687 
   688 * Isar/Pure: new derived language element 'obtain' supports
   689 generalized existence reasoning;
   690 
   691 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   692 support accumulation of results, without applying any rules yet;
   693 useful to collect intermediate results without explicit name
   694 references, and for use with transitivity rules with more than 2
   695 premises;
   696 
   697 * Isar/Pure: scalable support for case-analysis type proofs: new
   698 'case' language element refers to local contexts symbolically, as
   699 produced by certain proof methods; internally, case names are attached
   700 to theorems as "tags";
   701 
   702 * Isar/Pure: theory command 'hide' removes declarations from
   703 class/type/const name spaces;
   704 
   705 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   706 indicate potential overloading;
   707 
   708 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   709 
   710 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   711 "{a,b,c}" instead of {a,b,c};
   712 
   713 * Isar/Pure now provides its own version of intro/elim/dest
   714 attributes; useful for building new logics, but beware of confusion
   715 with the version in Provers/classical;
   716 
   717 * Isar/Pure: the local context of (non-atomic) goals is provided via
   718 case name 'antecedent';
   719 
   720 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   721 to the current context is now done automatically);
   722 
   723 * Isar/Pure: theory command 'method_setup' provides a simple interface
   724 for definining proof methods in ML;
   725 
   726 * Isar/Provers: intro/elim/dest attributes changed; renamed
   727 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   728 most cases, one should have to change intro!! to intro? only);
   729 replaced "delrule" by "rule del";
   730 
   731 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   732 'symmetric' attribute (the latter supercedes [RS sym]);
   733 
   734 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   735 method modifier); 'simp' method: 'only:' modifier removes loopers as
   736 well (including splits);
   737 
   738 * Isar/Provers: Simplifier and Classical methods now support all kind
   739 of modifiers used in the past, including 'cong', 'iff', etc.
   740 
   741 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   742 of Simplifier and Classical reasoner);
   743 
   744 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   745 now support named cases; major packages (inductive, datatype, primrec,
   746 recdef) support case names and properly name parameters;
   747 
   748 * Isar/HOL: new transitivity rules for substitution in inequalities --
   749 monotonicity conditions are extracted to be proven at end of
   750 calculations;
   751 
   752 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   753 method anyway;
   754 
   755 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   756 split_if split_if_asm; datatype package provides theorems foo.splits =
   757 foo.split foo.split_asm for each datatype;
   758 
   759 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   760 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   761 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   762 use "(cases (simplified))" method in proper proof texts);
   763 
   764 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   765 
   766 * Isar: names of theorems etc. may be natural numbers as well;
   767 
   768 * Isar: 'pr' command: optional arguments for goals_limit and
   769 ProofContext.prems_limit; no longer prints theory contexts, but only
   770 proof states;
   771 
   772 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   773 additional print modes to be specified; e.g. "pr(latex)" will print
   774 proof state according to the Isabelle LaTeX style;
   775 
   776 * Isar: improved support for emulating tactic scripts, including proof
   777 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   778 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   779 (for HOL datatypes);
   780 
   781 * Isar: simplified (more robust) goal selection of proof methods: 1st
   782 goal, all goals, or explicit goal specifier (tactic emulation); thus
   783 'proof method scripts' have to be in depth-first order;
   784 
   785 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   786 
   787 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   788 should instead use individual commands for printing items
   789 (print_commands, print_methods etc.);
   790 
   791 * Isar: added 'nothing' --- the empty list of theorems;
   792 
   793 
   794 *** HOL ***
   795 
   796 * HOL/MicroJava: formalization of a fragment of Java, together with a
   797 corresponding virtual machine and a specification of its bytecode
   798 verifier and a lightweight bytecode verifier, including proofs of
   799 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   800 Cornelia Pusch (see also the homepage of project Bali at
   801 http://isabelle.in.tum.de/Bali/);
   802 
   803 * HOL/Algebra: new theory of rings and univariate polynomials, by
   804 Clemens Ballarin;
   805 
   806 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   807 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   808 Rasmussen;
   809 
   810 * HOL/Lattice: fundamental concepts of lattice theory and order
   811 structures, including duals, properties of bounds versus algebraic
   812 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   813 Theorem for complete lattices etc.; may also serve as a demonstration
   814 for abstract algebraic reasoning using axiomatic type classes, and
   815 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   816 
   817 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   818 von Oheimb;
   819 
   820 * HOL/IMPP: extension of IMP with local variables and mutually
   821 recursive procedures, by David von Oheimb;
   822 
   823 * HOL/Lambda: converted into new-style theory and document;
   824 
   825 * HOL/ex/Multiquote: example of multiple nested quotations and
   826 anti-quotations -- basically a generalized version of de-Bruijn
   827 representation; very useful in avoiding lifting of operations;
   828 
   829 * HOL/record: added general record equality rule to simpset; fixed
   830 select-update simplification procedure to handle extended records as
   831 well; admit "r" as field name;
   832 
   833 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   834 other numeric types and also as the identity of groups, rings, etc.;
   835 
   836 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   837 Types nat and int belong to this axclass;
   838 
   839 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   840    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   841    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   842   two terms #m*u and #n*u are replaced by #(m+n)*u
   843     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   844   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   845     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   846 
   847 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   848 powerful prover for predicate logic but knows nothing of clasets; see
   849 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   850 
   851 * HOL: new version of "case_tac" subsumes both boolean case split and
   852 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   853 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   854 
   855 * HOL: simplification no longer dives into case-expressions: only the
   856 selector expression is simplified, but not the remaining arms; to
   857 enable full simplification of case-expressions for datatype t, you may
   858 remove t.weak_case_cong from the simpset, either globally (Delcongs
   859 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   860 
   861 * HOL/recdef: the recursion equations generated by 'recdef' for
   862 function 'f' are now called f.simps instead of f.rules; if all
   863 termination conditions are proved automatically, these simplification
   864 rules are added to the simpset, as in primrec; rules may be named
   865 individually as well, resulting in a separate list of theorems for
   866 each equation;
   867 
   868 * HOL/While is a new theory that provides a while-combinator. It
   869 permits the definition of tail-recursive functions without the
   870 provision of a termination measure. The latter is necessary once the
   871 invariant proof rule for while is applied.
   872 
   873 * HOL: new (overloaded) notation for the set of elements below/above
   874 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   875 
   876 * HOL: theorems impI, allI, ballI bound as "strip";
   877 
   878 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   879 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   880 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   881 
   882 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   883 
   884 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   885 main HOL, but was unused);
   886 
   887 * HOL: fewer consts declared as global (e.g. have to refer to
   888 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   889 
   890 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   891 in case of overlap with user translations (e.g. judgements over
   892 tuples); (note that the underlying logical represenation is still
   893 bogus);
   894 
   895 
   896 *** ZF ***
   897 
   898 * ZF: simplification automatically cancels common terms in arithmetic
   899 expressions over nat and int;
   900 
   901 * ZF: new treatment of nat to minimize type-checking: all operators
   902 coerce their operands to a natural number using the function natify,
   903 making the algebraic laws unconditional;
   904 
   905 * ZF: as above, for int: operators coerce their operands to an integer
   906 using the function intify;
   907 
   908 * ZF: the integer library now contains many of the usual laws for the
   909 orderings, including $<=, and monotonicity laws for $+ and $*;
   910 
   911 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   912 simplification;
   913 
   914 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   915 to the simplifier and classical reasoner simultaneously;
   916 
   917 
   918 *** General ***
   919 
   920 * Provers: blast_tac now handles actual object-logic rules as
   921 assumptions; note that auto_tac uses blast_tac internally as well;
   922 
   923 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   924 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   925 
   926 * Provers: delrules now handles destruct rules as well (no longer need
   927 explicit make_elim);
   928 
   929 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   930   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   931 use instead the strong form,
   932   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   933 in HOL, FOL and ZF the function cla_make_elim will create such rules
   934 from destruct-rules;
   935 
   936 * Provers: Simplifier.easy_setup provides a fast path to basic
   937 Simplifier setup for new object-logics;
   938 
   939 * Pure: AST translation rules no longer require constant head on LHS;
   940 
   941 * Pure: improved name spaces: ambiguous output is qualified; support
   942 for hiding of names;
   943 
   944 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   945 XSYMBOL_HOME; no longer need to do manual configuration in most
   946 situations;
   947 
   948 * system: compression of ML heaps images may now be controlled via -c
   949 option of isabelle and isatool usedir (currently only observed by
   950 Poly/ML);
   951 
   952 * system: isatool installfonts may handle X-Symbol fonts as well (very
   953 useful for remote X11);
   954 
   955 * system: provide TAGS file for Isabelle sources;
   956 
   957 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   958 order;
   959 
   960 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   961 timing flag supersedes proof_timing and Toplevel.trace;
   962 
   963 * ML: new combinators |>> and |>>> for incremental transformations
   964 with secondary results (e.g. certain theory extensions):
   965 
   966 * ML: PureThy.add_defs gets additional argument to indicate potential
   967 overloading (usually false);
   968 
   969 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   970 results;
   971 
   972 
   973 
   974 New in Isabelle99 (October 1999)
   975 --------------------------------
   976 
   977 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   978 
   979 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   980 are no longer simplified.  (This allows the simplifier to unfold recursive
   981 functional programs.)  To restore the old behaviour, declare
   982 
   983     Delcongs [if_weak_cong];
   984 
   985 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   986 complement;
   987 
   988 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   989 
   990 * HOL/datatype: mutual_induct_tac no longer exists --
   991   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   992 
   993 * HOL/typedef: fixed type inference for representing set; type
   994 arguments now have to occur explicitly on the rhs as type constraints;
   995 
   996 * ZF: The con_defs part of an inductive definition may no longer refer
   997 to constants declared in the same theory;
   998 
   999 * HOL, ZF: the function mk_cases, generated by the inductive
  1000 definition package, has lost an argument.  To simplify its result, it
  1001 uses the default simpset instead of a supplied list of theorems.
  1002 
  1003 * HOL/List: the constructors of type list are now Nil and Cons;
  1004 
  1005 * Simplifier: the type of the infix ML functions
  1006         setSSolver addSSolver setSolver addSolver
  1007 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1008 for packaging solvers. A solver is created via
  1009         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1010 where the string argument is only a comment.
  1011 
  1012 
  1013 *** Proof tools ***
  1014 
  1015 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1016 decision procedure for linear arithmetic. Currently it is used for
  1017 types `nat', `int', and `real' in HOL (see below); it can, should and
  1018 will be instantiated for other types and logics as well.
  1019 
  1020 * The simplifier now accepts rewrite rules with flexible heads, eg
  1021      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1022   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1023   matching.
  1024 
  1025 
  1026 *** General ***
  1027 
  1028 * New Isabelle/Isar subsystem provides an alternative to traditional
  1029 tactical theorem proving; together with the ProofGeneral/isar user
  1030 interface it offers an interactive environment for developing human
  1031 readable proof documents (Isar == Intelligible semi-automated
  1032 reasoning); for further information see isatool doc isar-ref,
  1033 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1034 
  1035 * improved and simplified presentation of theories: better HTML markup
  1036 (including colors), graph views in several sizes; isatool usedir now
  1037 provides a proper interface for user theories (via -P option); actual
  1038 document preparation based on (PDF)LaTeX is available as well (for
  1039 new-style theories only); see isatool doc system for more information;
  1040 
  1041 * native support for Proof General, both for classic Isabelle and
  1042 Isabelle/Isar;
  1043 
  1044 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1045 using the graph browser tool;
  1046 
  1047 * Isabelle manuals now also available as PDF;
  1048 
  1049 * theory loader rewritten from scratch (may not be fully
  1050 bug-compatible); old loadpath variable has been replaced by show_path,
  1051 add_path, del_path, reset_path functions; new operations such as
  1052 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1053 isatool doc ref);
  1054 
  1055 * improved isatool install: option -k creates KDE application icon,
  1056 option -p DIR installs standalone binaries;
  1057 
  1058 * added ML_PLATFORM setting (useful for cross-platform installations);
  1059 more robust handling of platform specific ML images for SML/NJ;
  1060 
  1061 * the settings environment is now statically scoped, i.e. it is never
  1062 created again in sub-processes invoked from isabelle, isatool, or
  1063 Isabelle;
  1064 
  1065 * path element specification '~~' refers to '$ISABELLE_HOME';
  1066 
  1067 * in locales, the "assumes" and "defines" parts may be omitted if
  1068 empty;
  1069 
  1070 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1071 long arrows);
  1072 
  1073 * new print_mode "HTML";
  1074 
  1075 * new flag show_tags controls display of tags of theorems (which are
  1076 basically just comments that may be attached by some tools);
  1077 
  1078 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1079 mode and goal output format:
  1080 
  1081 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1082 244c244
  1083 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1084 ---
  1085 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1086 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1087 181c181
  1088 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1089 ---
  1090 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1091 
  1092 * function bind_thms stores lists of theorems (cf. bind_thm);
  1093 
  1094 * new shorthand tactics ftac, eatac, datac, fatac;
  1095 
  1096 * qed (and friends) now accept "" as result name; in that case the
  1097 theorem is not stored, but proper checks and presentation of the
  1098 result still apply;
  1099 
  1100 * theorem database now also indexes constants "Trueprop", "all",
  1101 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1102 
  1103 
  1104 *** HOL ***
  1105 
  1106 ** HOL arithmetic **
  1107 
  1108 * There are now decision procedures for linear arithmetic over nat and
  1109 int:
  1110 
  1111 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1112 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1113 are treated as atomic; subformulae not involving type `nat' or `int'
  1114 are ignored; quantified subformulae are ignored unless they are
  1115 positive universal or negative existential. The tactic has to be
  1116 invoked by hand and can be a little bit slow. In particular, the
  1117 running time is exponential in the number of occurrences of `min' and
  1118 `max', and `-' on `nat'.
  1119 
  1120 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1121 (negated) (in)equalities among the premises and the conclusion into
  1122 account (i.e. no compound formulae) and does not know about `min' and
  1123 `max', and `-' on `nat'. It is fast and is used automatically by the
  1124 simplifier.
  1125 
  1126 NB: At the moment, these decision procedures do not cope with mixed
  1127 nat/int formulae where the two parts interact, such as `m < n ==>
  1128 int(m) < int(n)'.
  1129 
  1130 * HOL/Numeral provides a generic theory of numerals (encoded
  1131 efficiently as bit strings); setup for types nat/int/real is in place;
  1132 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1133 int, existing theories and proof scripts may require a few additional
  1134 type constraints;
  1135 
  1136 * integer division and remainder can now be performed on constant
  1137 arguments;
  1138 
  1139 * many properties of integer multiplication, division and remainder
  1140 are now available;
  1141 
  1142 * An interface to the Stanford Validity Checker (SVC) is available through the
  1143 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1144 are proved automatically.  SVC must be installed separately, and its results
  1145 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1146 invocation of the underlying oracle).  For SVC see
  1147   http://verify.stanford.edu/SVC
  1148 
  1149 * IsaMakefile: the HOL-Real target now builds an actual image;
  1150 
  1151 
  1152 ** HOL misc **
  1153 
  1154 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1155 (in Isabelle/Isar) -- by Gertrud Bauer;
  1156 
  1157 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1158 analysis for assembly languages with subtypes;
  1159 
  1160 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1161 -- avoids syntactic ambiguities and treats state, transition, and
  1162 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1163 changed syntax and (many) tactics;
  1164 
  1165 * HOL/inductive: Now also handles more general introduction rules such
  1166   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1167   theorems are now maintained within the theory (maintained via the
  1168   "mono" attribute);
  1169 
  1170 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1171   (using function types) such as
  1172 
  1173   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1174 
  1175 * HOL/record: record_simproc (part of the default simpset) takes care
  1176 of selectors applied to updated records; record_split_tac is no longer
  1177 part of the default claset; update_defs may now be removed from the
  1178 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1179 
  1180   claset_ref () := claset() addSWrapper record_split_wrapper;
  1181   Delsimprocs [record_simproc]
  1182 
  1183 * HOL/typedef: fixed type inference for representing set; type
  1184 arguments now have to occur explicitly on the rhs as type constraints;
  1185 
  1186 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1187 names rather than an ML expression;
  1188 
  1189 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1190 supplied later.  Program schemes can be defined, such as
  1191     "While B C s = (if B s then While B C (C s) else s)"
  1192 where the well-founded relation can be chosen after B and C have been given.
  1193 
  1194 * HOL/List: the constructors of type list are now Nil and Cons;
  1195 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1196 course, ML tools referring to List.list.op # etc. have to be adapted;
  1197 
  1198 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1199 disabled by default; run isabelle with option -m HOL to get back to
  1200 the original Gordon/HOL-style output;
  1201 
  1202 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1203 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1204 
  1205 * HOL basic syntax simplified (more orthogonal): all variants of
  1206 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1207 Eps operator is provided as well: "SOME x. P[x]";
  1208 
  1209 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1210 
  1211 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1212 thus available for user theories;
  1213 
  1214 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1215 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1216 time;
  1217 
  1218 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1219 several times and then mp;
  1220 
  1221 
  1222 *** LK ***
  1223 
  1224 * the notation <<...>> is now available as a notation for sequences of
  1225 formulas;
  1226 
  1227 * the simplifier is now installed
  1228 
  1229 * the axiom system has been generalized (thanks to Soren Heilmann)
  1230 
  1231 * the classical reasoner now has a default rule database
  1232 
  1233 
  1234 *** ZF ***
  1235 
  1236 * new primrec section allows primitive recursive functions to be given
  1237 directly (as in HOL) over datatypes and the natural numbers;
  1238 
  1239 * new tactics induct_tac and exhaust_tac for induction (or case
  1240 analysis) over datatypes and the natural numbers;
  1241 
  1242 * the datatype declaration of type T now defines the recursor T_rec;
  1243 
  1244 * simplification automatically does freeness reasoning for datatype
  1245 constructors;
  1246 
  1247 * automatic type-inference, with AddTCs command to insert new
  1248 type-checking rules;
  1249 
  1250 * datatype introduction rules are now added as Safe Introduction rules
  1251 to the claset;
  1252 
  1253 * the syntax "if P then x else y" is now available in addition to
  1254 if(P,x,y);
  1255 
  1256 
  1257 *** Internal programming interfaces ***
  1258 
  1259 * tuned simplifier trace output; new flag debug_simp;
  1260 
  1261 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1262 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1263 
  1264 * AxClass.axclass_tac lost the theory argument;
  1265 
  1266 * tuned current_goals_markers semantics: begin / end goal avoids
  1267 printing empty lines;
  1268 
  1269 * removed prs and prs_fn hook, which was broken because it did not
  1270 include \n in its semantics, forcing writeln to add one
  1271 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1272 string -> unit if you really want to output text without newline;
  1273 
  1274 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1275 plain output, interface builders may have to enable 'isabelle_font'
  1276 mode to get Isabelle font glyphs as before;
  1277 
  1278 * refined token_translation interface; INCOMPATIBILITY: output length
  1279 now of type real instead of int;
  1280 
  1281 * theory loader actions may be traced via new ThyInfo.add_hook
  1282 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1283 your own database of information attached to *whole* theories -- as
  1284 opposed to intra-theory data slots offered via TheoryDataFun;
  1285 
  1286 * proper handling of dangling sort hypotheses (at last!);
  1287 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1288 extra sort hypotheses that can be witnessed from the type signature;
  1289 the force_strip_shyps flag is gone, any remaining shyps are simply
  1290 left in the theorem (with a warning issued by strip_shyps_warning);
  1291 
  1292 
  1293 
  1294 New in Isabelle98-1 (October 1998)
  1295 ----------------------------------
  1296 
  1297 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1298 
  1299 * several changes of automated proof tools;
  1300 
  1301 * HOL: major changes to the inductive and datatype packages, including
  1302 some minor incompatibilities of theory syntax;
  1303 
  1304 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1305 called `inj_on';
  1306 
  1307 * HOL: removed duplicate thms in Arith:
  1308   less_imp_add_less  should be replaced by  trans_less_add1
  1309   le_imp_add_le      should be replaced by  trans_le_add1
  1310 
  1311 * HOL: unary minus is now overloaded (new type constraints may be
  1312 required);
  1313 
  1314 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1315 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1316 now taken as an integer constant.
  1317 
  1318 * Pure: ML function 'theory_of' renamed to 'theory';
  1319 
  1320 
  1321 *** Proof tools ***
  1322 
  1323 * Simplifier:
  1324   1. Asm_full_simp_tac is now more aggressive.
  1325      1. It will sometimes reorient premises if that increases their power to
  1326         simplify.
  1327      2. It does no longer proceed strictly from left to right but may also
  1328         rotate premises to achieve further simplification.
  1329      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1330      old Asm_full_simp_tac in that it does not rotate premises.
  1331   2. The simplifier now knows a little bit about nat-arithmetic.
  1332 
  1333 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1334 allows for selected deletion of wrappers, by introduction of names for
  1335 wrapper functionals.  This implies that addbefore, addSbefore,
  1336 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1337 and that adding two tactics with the same name overwrites the first
  1338 one (emitting a warning).
  1339   type wrapper = (int -> tactic) -> (int -> tactic)
  1340   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1341   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1342   delWrapper, delSWrapper: claset *  string            -> claset
  1343   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1344 
  1345 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1346 semantics; addbefore now affects only the unsafe part of step_tac
  1347 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1348 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1349 by Force_tac;
  1350 
  1351 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1352 compWrapper; added safe wrapper (and access functions for it);
  1353 
  1354 * HOL/split_all_tac is now much faster and fails if there is nothing
  1355 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1356 and the names of the automatically generated variables have changed.
  1357 split_all_tac has moved within claset() from unsafe wrappers to safe
  1358 wrappers, which means that !!-bound variables are split much more
  1359 aggressively, and safe_tac and clarify_tac now split such variables.
  1360 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1361 Note: the same holds for record_split_tac, which does the job of
  1362 split_all_tac for record fields.
  1363 
  1364 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1365 permanently to the default simpset using Addsplits just like
  1366 Addsimps. They can be removed via Delsplits just like
  1367 Delsimps. Lower-case versions are also available.
  1368 
  1369 * HOL/Simplifier: The rule split_if is now part of the default
  1370 simpset. This means that the simplifier will eliminate all occurrences
  1371 of if-then-else in the conclusion of a goal. To prevent this, you can
  1372 either remove split_if completely from the default simpset by
  1373 `Delsplits [split_if]' or remove it in a specific call of the
  1374 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1375 other case splitting rules to/from the default simpset: every datatype
  1376 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1377 t is the name of the datatype).
  1378 
  1379 * Classical reasoner / Simplifier combination: new force_tac (and
  1380 derivatives Force_tac, force) combines rewriting and classical
  1381 reasoning (and whatever other tools) similarly to auto_tac, but is
  1382 aimed to solve the given subgoal completely.
  1383 
  1384 
  1385 *** General ***
  1386 
  1387 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1388 and `goalw': the theory is no longer needed as an explicit argument -
  1389 the current theory context is used; assumptions are no longer returned
  1390 at the ML-level unless one of them starts with ==> or !!; it is
  1391 recommended to convert to these new commands using isatool fixgoal
  1392 (backup your sources first!);
  1393 
  1394 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1395 the current theory context, and 'theory' to lookup stored theories;
  1396 
  1397 * new theory section 'locale' for declaring constants, assumptions and
  1398 definitions that have local scope;
  1399 
  1400 * new theory section 'nonterminals' for purely syntactic types;
  1401 
  1402 * new theory section 'setup' for generic ML setup functions
  1403 (e.g. package initialization);
  1404 
  1405 * the distribution now includes Isabelle icons: see
  1406 lib/logo/isabelle-{small,tiny}.xpm;
  1407 
  1408 * isatool install - install binaries with absolute references to
  1409 ISABELLE_HOME/bin;
  1410 
  1411 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1412 
  1413 * print mode 'emacs' reserved for Isamode;
  1414 
  1415 * support multiple print (ast) translations per constant name;
  1416 
  1417 * theorems involving oracles are now printed with a suffixed [!];
  1418 
  1419 
  1420 *** HOL ***
  1421 
  1422 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1423 
  1424 * HOL/inductive package reorganized and improved: now supports mutual
  1425 definitions such as
  1426 
  1427   inductive EVEN ODD
  1428     intrs
  1429       null "0 : EVEN"
  1430       oddI "n : EVEN ==> Suc n : ODD"
  1431       evenI "n : ODD ==> Suc n : EVEN"
  1432 
  1433 new theorem list "elims" contains an elimination rule for each of the
  1434 recursive sets; inductive definitions now handle disjunctive premises
  1435 correctly (also ZF);
  1436 
  1437 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1438 "mutual_induct" no longer exists - the induction rule is always
  1439 contained in "induct";
  1440 
  1441 
  1442 * HOL/datatype package re-implemented and greatly improved: now
  1443 supports mutually recursive datatypes such as
  1444 
  1445   datatype
  1446     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1447             | SUM ('a aexp) ('a aexp)
  1448             | DIFF ('a aexp) ('a aexp)
  1449             | NUM 'a
  1450   and
  1451     'a bexp = LESS ('a aexp) ('a aexp)
  1452             | AND ('a bexp) ('a bexp)
  1453             | OR ('a bexp) ('a bexp)
  1454 
  1455 as well as indirectly recursive datatypes such as
  1456 
  1457   datatype
  1458     ('a, 'b) term = Var 'a
  1459                   | App 'b ((('a, 'b) term) list)
  1460 
  1461 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1462 induction on mutually / indirectly recursive datatypes.
  1463 
  1464 Primrec equations are now stored in theory and can be accessed via
  1465 <function_name>.simps.
  1466 
  1467 INCOMPATIBILITIES:
  1468 
  1469   - Theories using datatypes must now have theory Datatype as an
  1470     ancestor.
  1471   - The specific <typename>.induct_tac no longer exists - use the
  1472     generic induct_tac instead.
  1473   - natE has been renamed to nat.exhaust - use exhaust_tac
  1474     instead of res_inst_tac ... natE. Note that the variable
  1475     names in nat.exhaust differ from the names in natE, this
  1476     may cause some "fragile" proofs to fail.
  1477   - The theorems split_<typename>_case and split_<typename>_case_asm
  1478     have been renamed to <typename>.split and <typename>.split_asm.
  1479   - Since default sorts of type variables are now handled correctly,
  1480     some datatype definitions may have to be annotated with explicit
  1481     sort constraints.
  1482   - Primrec definitions no longer require function name and type
  1483     of recursive argument.
  1484 
  1485 Consider using isatool fixdatatype to adapt your theories and proof
  1486 scripts to the new package (backup your sources first!).
  1487 
  1488 
  1489 * HOL/record package: considerably improved implementation; now
  1490 includes concrete syntax for record types, terms, updates; theorems
  1491 for surjective pairing and splitting !!-bound record variables; proof
  1492 support is as follows:
  1493 
  1494   1) standard conversions (selectors or updates applied to record
  1495 constructor terms) are part of the standard simpset;
  1496 
  1497   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1498 made part of standard simpset and claset via addIffs;
  1499 
  1500   3) a tactic for record field splitting (record_split_tac) is part of
  1501 the standard claset (addSWrapper);
  1502 
  1503 To get a better idea about these rules you may retrieve them via
  1504 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1505 the name of your record type.
  1506 
  1507 The split tactic 3) conceptually simplifies by the following rule:
  1508 
  1509   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1510 
  1511 Thus any record variable that is bound by meta-all will automatically
  1512 blow up into some record constructor term, consequently the
  1513 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1514 solve record problems automatically.
  1515 
  1516 
  1517 * reorganized the main HOL image: HOL/Integ and String loaded by
  1518 default; theory Main includes everything;
  1519 
  1520 * automatic simplification of integer sums and comparisons, using cancellation;
  1521 
  1522 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1523 
  1524 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1525 
  1526 * many new identities for unions, intersections, set difference, etc.;
  1527 
  1528 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1529 called split_if, split_split, split_sum_case and split_nat_case (to go
  1530 with add/delsplits);
  1531 
  1532 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1533 (?x::unit) = (); this is made part of the default simpset, which COULD
  1534 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1535 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1536 unit_abs_eta_conv is added in order to counter the effect of
  1537 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1538 %u.f();
  1539 
  1540 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1541 makes more sense);
  1542 
  1543 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1544   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1545   disjointness reasoning but breaking a few old proofs.
  1546 
  1547 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1548 to 'converse' from 'inverse' (for compatibility with ZF and some
  1549 literature);
  1550 
  1551 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1552 the well-founded relation;
  1553 
  1554 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1555     Compl A.  The "Compl" syntax remains available as input syntax for this
  1556     release ONLY.
  1557 
  1558 * HOL/Update: new theory of function updates:
  1559     f(a:=b) == %x. if x=a then b else f x
  1560 may also be iterated as in f(a:=b,c:=d,...);
  1561 
  1562 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1563 
  1564 * HOL/List:
  1565   - new function list_update written xs[i:=v] that updates the i-th
  1566     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1567   - new function `upt' written [i..j(] which generates the list
  1568     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1569     bound write [i..j], which is a shorthand for [i..j+1(].
  1570   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1571 
  1572 * HOL/Arith:
  1573   - removed 'pred' (predecessor) function;
  1574   - generalized some theorems about n-1;
  1575   - many new laws about "div" and "mod";
  1576   - new laws about greatest common divisors (see theory ex/Primes);
  1577 
  1578 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1579 instead of "inverse";
  1580 
  1581 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1582   of the multiset ordering;
  1583 
  1584 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1585   (not included by default);
  1586 
  1587 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1588 
  1589 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1590   programs, i.e. different program variables may have different types.
  1591 
  1592 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1593   [previously, this check worked only if the rewrite rule was unconditional]
  1594   Now rew can involve either definitions or equalities (either == or =).
  1595 
  1596 
  1597 *** ZF ***
  1598 
  1599 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1600   only the theorems proved on ZF.ML;
  1601 
  1602 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1603   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1604   disjointness reasoning but breaking a few old proofs.
  1605 
  1606 * ZF/Update: new theory of function updates
  1607     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1608   may also be iterated as in f(a:=b,c:=d,...);
  1609 
  1610 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1611 
  1612 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1613   [previously, this check worked only if the rewrite rule was unconditional]
  1614   Now rew can involve either definitions or equalities (either == or =).
  1615 
  1616 * case_tac provided for compatibility with HOL
  1617     (like the old excluded_middle_tac, but with subgoals swapped)
  1618 
  1619 
  1620 *** Internal programming interfaces ***
  1621 
  1622 * Pure: several new basic modules made available for general use, see
  1623 also src/Pure/README;
  1624 
  1625 * improved the theory data mechanism to support encapsulation (data
  1626 kind name replaced by private Object.kind, acting as authorization
  1627 key); new type-safe user interface via functor TheoryDataFun; generic
  1628 print_data function becomes basically useless;
  1629 
  1630 * removed global_names compatibility flag -- all theory declarations
  1631 are qualified by default;
  1632 
  1633 * module Pure/Syntax now offers quote / antiquote translation
  1634 functions (useful for Hoare logic etc. with implicit dependencies);
  1635 see HOL/ex/Antiquote for an example use;
  1636 
  1637 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1638 cterm -> thm;
  1639 
  1640 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1641 subgoal;
  1642 
  1643 * Display.print_goals function moved to Locale.print_goals;
  1644 
  1645 * standard print function for goals supports current_goals_markers
  1646 variable for marking begin of proof, end of proof, start of goal; the
  1647 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1648 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1649 for example;
  1650 
  1651 
  1652 
  1653 New in Isabelle98 (January 1998)
  1654 --------------------------------
  1655 
  1656 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1657 
  1658 * changed lexical syntax of terms / types: dots made part of long
  1659 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1660 
  1661 * simpset (and claset) reference variable replaced by functions
  1662 simpset / simpset_ref;
  1663 
  1664 * no longer supports theory aliases (via merge) and non-trivial
  1665 implicit merge of thms' signatures;
  1666 
  1667 * most internal names of constants changed due to qualified names;
  1668 
  1669 * changed Pure/Sequence interface (see Pure/seq.ML);
  1670 
  1671 
  1672 *** General Changes ***
  1673 
  1674 * hierachically structured name spaces (for consts, types, axms, thms
  1675 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1676 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1677 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1678 long_names for fully qualified output names; NOTE: ML programs
  1679 (special tactics, packages etc.) referring to internal names may have
  1680 to be adapted to cope with fully qualified names; in case of severe
  1681 backward campatibility problems try setting 'global_names' at compile
  1682 time to have enrything declared within a flat name space; one may also
  1683 fine tune name declarations in theories via the 'global' and 'local'
  1684 section;
  1685 
  1686 * reimplemented the implicit simpset and claset using the new anytype
  1687 data filed in signatures; references simpset:simpset ref etc. are
  1688 replaced by functions simpset:unit->simpset and
  1689 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1690 to patch your ML files accordingly;
  1691 
  1692 * HTML output now includes theory graph data for display with Java
  1693 applet or isatool browser; data generated automatically via isatool
  1694 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1695 
  1696 * defs may now be conditional; improved rewrite_goals_tac to handle
  1697 conditional equations;
  1698 
  1699 * defs now admits additional type arguments, using TYPE('a) syntax;
  1700 
  1701 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1702 creates a new theory node; implicit merge of thms' signatures is
  1703 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1704 transfer:theory->thm->thm in (rare) cases;
  1705 
  1706 * improved handling of draft signatures / theories; draft thms (and
  1707 ctyps, cterms) are automatically promoted to real ones;
  1708 
  1709 * slightly changed interfaces for oracles: admit many per theory, named
  1710 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1711 
  1712 * print_goals: optional output of const types (set show_consts and
  1713 show_types);
  1714 
  1715 * improved output of warnings (###) and errors (***);
  1716 
  1717 * subgoal_tac displays a warning if the new subgoal has type variables;
  1718 
  1719 * removed old README and Makefiles;
  1720 
  1721 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1722 
  1723 * removed obsolete init_pps and init_database;
  1724 
  1725 * deleted the obsolete tactical STATE, which was declared by
  1726     fun STATE tacfun st = tacfun st st;
  1727 
  1728 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1729 (which abbreviates $HOME);
  1730 
  1731 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1732 use isatool fixseq to adapt your ML programs (this works for fully
  1733 qualified references to the Sequence structure only!);
  1734 
  1735 * use_thy no longer requires writable current directory; it always
  1736 reloads .ML *and* .thy file, if either one is out of date;
  1737 
  1738 
  1739 *** Classical Reasoner ***
  1740 
  1741 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1742 tactics that use classical reasoning to simplify a subgoal without
  1743 splitting it into several subgoals;
  1744 
  1745 * Safe_tac: like safe_tac but uses the default claset;
  1746 
  1747 
  1748 *** Simplifier ***
  1749 
  1750 * added simplification meta rules:
  1751     (asm_)(full_)simplify: simpset -> thm -> thm;
  1752 
  1753 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1754 logics (again);
  1755 
  1756 * added prems argument to simplification procedures;
  1757 
  1758 * HOL, FOL, ZF: added infix function `addsplits':
  1759   instead of `<simpset> setloop (split_tac <thms>)'
  1760   you can simply write `<simpset> addsplits <thms>'
  1761 
  1762 
  1763 *** Syntax ***
  1764 
  1765 * TYPE('a) syntax for type reflection terms;
  1766 
  1767 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1768 
  1769 * pretty printer: changed order of mixfix annotation preference (again!);
  1770 
  1771 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1772 
  1773 
  1774 *** HOL ***
  1775 
  1776 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1777   with `addloop' of the simplifier to faciliate case splitting in premises.
  1778 
  1779 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1780 
  1781 * HOL/Auth: new protocol proofs including some for the Internet
  1782   protocol TLS;
  1783 
  1784 * HOL/Map: new theory of `maps' a la VDM;
  1785 
  1786 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1787 cancelling out common nat summands from =, <, <= (in)equalities, or
  1788 differences; simplification procedures nat_cancel_factor for
  1789 cancelling common factor from =, <, <= (in)equalities over natural
  1790 sums; nat_cancel contains both kinds of procedures, it is installed by
  1791 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1792 
  1793 * HOL/simplifier: terms of the form
  1794   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1795   are rewritten to
  1796   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1797   and those of the form
  1798   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1799   are rewritten to
  1800   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1801 
  1802 * HOL/datatype
  1803   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1804 
  1805   P(t_case f1 ... fn x) =
  1806      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1807         ...
  1808        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1809      )
  1810 
  1811   and a theorem `split_t_case_asm' of the form
  1812 
  1813   P(t_case f1 ... fn x) =
  1814     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1815         ...
  1816        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1817      )
  1818   which can be added to a simpset via `addsplits'. The existing theorems
  1819   expand_list_case and expand_option_case have been renamed to
  1820   split_list_case and split_option_case.
  1821 
  1822 * HOL/Arithmetic:
  1823   - `pred n' is automatically converted to `n-1'.
  1824     Users are strongly encouraged not to use `pred' any longer,
  1825     because it will disappear altogether at some point.
  1826   - Users are strongly encouraged to write "0 < n" rather than
  1827     "n ~= 0". Theorems and proof tools have been modified towards this
  1828     `standard'.
  1829 
  1830 * HOL/Lists:
  1831   the function "set_of_list" has been renamed "set" (and its theorems too);
  1832   the function "nth" now takes its arguments in the reverse order and
  1833   has acquired the infix notation "!" as in "xs!n".
  1834 
  1835 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1836 
  1837 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1838   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1839 
  1840 * HOL/record: extensible records with schematic structural subtyping
  1841 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1842 still lacks various theorems and concrete record syntax;
  1843 
  1844 
  1845 *** HOLCF ***
  1846 
  1847 * removed "axioms" and "generated by" sections;
  1848 
  1849 * replaced "ops" section by extended "consts" section, which is capable of
  1850   handling the continuous function space "->" directly;
  1851 
  1852 * domain package:
  1853   . proves theorems immediately and stores them in the theory,
  1854   . creates hierachical name space,
  1855   . now uses normal mixfix annotations (instead of cinfix...),
  1856   . minor changes to some names and values (for consistency),
  1857   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1858   . separator between mutual domain defs: changed "," to "and",
  1859   . improved handling of sort constraints;  now they have to
  1860     appear on the left-hand side of the equations only;
  1861 
  1862 * fixed LAM <x,y,zs>.b syntax;
  1863 
  1864 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1865 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1866 
  1867 
  1868 *** FOL and ZF ***
  1869 
  1870 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1871   with `addloop' of the simplifier to faciliate case splitting in premises.
  1872 
  1873 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1874 in HOL, they strip ALL and --> from proved theorems;
  1875 
  1876 
  1877 
  1878 New in Isabelle94-8 (May 1997)
  1879 ------------------------------
  1880 
  1881 *** General Changes ***
  1882 
  1883 * new utilities to build / run / maintain Isabelle etc. (in parts
  1884 still somewhat experimental); old Makefiles etc. still functional;
  1885 
  1886 * new 'Isabelle System Manual';
  1887 
  1888 * INSTALL text, together with ./configure and ./build scripts;
  1889 
  1890 * reimplemented type inference for greater efficiency, better error
  1891 messages and clean internal interface;
  1892 
  1893 * prlim command for dealing with lots of subgoals (an easier way of
  1894 setting goals_limit);
  1895 
  1896 
  1897 *** Syntax ***
  1898 
  1899 * supports alternative (named) syntax tables (parser and pretty
  1900 printer); internal interface is provided by add_modesyntax(_i);
  1901 
  1902 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1903 be used in conjunction with the Isabelle symbol font; uses the
  1904 "symbols" syntax table;
  1905 
  1906 * added token_translation interface (may translate name tokens in
  1907 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1908 the current print_mode); IMPORTANT: user print translation functions
  1909 are responsible for marking newly introduced bounds
  1910 (Syntax.mark_boundT);
  1911 
  1912 * token translations for modes "xterm" and "xterm_color" that display
  1913 names in bold, underline etc. or colors (which requires a color
  1914 version of xterm);
  1915 
  1916 * infixes may now be declared with names independent of their syntax;
  1917 
  1918 * added typed_print_translation (like print_translation, but may
  1919 access type of constant);
  1920 
  1921 
  1922 *** Classical Reasoner ***
  1923 
  1924 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1925 some limitations.  Blast_tac...
  1926   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1927   + ignores elimination rules that don't have the correct format
  1928         (the conclusion MUST be a formula variable)
  1929   + ignores types, which can make HOL proofs fail
  1930   + rules must not require higher-order unification, e.g. apply_type in ZF
  1931     [message "Function Var's argument not a bound variable" relates to this]
  1932   + its proof strategy is more general but can actually be slower
  1933 
  1934 * substitution with equality assumptions no longer permutes other
  1935 assumptions;
  1936 
  1937 * minor changes in semantics of addafter (now called addaltern); renamed
  1938 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1939 (and access functions for it);
  1940 
  1941 * improved combination of classical reasoner and simplifier:
  1942   + functions for handling clasimpsets
  1943   + improvement of addss: now the simplifier is called _after_ the
  1944     safe steps.
  1945   + safe variant of addss called addSss: uses safe simplifications
  1946     _during_ the safe steps. It is more complete as it allows multiple
  1947     instantiations of unknowns (e.g. with slow_tac).
  1948 
  1949 *** Simplifier ***
  1950 
  1951 * added interface for simplification procedures (functions that
  1952 produce *proven* rewrite rules on the fly, depending on current
  1953 redex);
  1954 
  1955 * ordering on terms as parameter (used for ordered rewriting);
  1956 
  1957 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1958 
  1959 * the solver is now split into a safe and an unsafe part.
  1960 This should be invisible for the normal user, except that the
  1961 functions setsolver and addsolver have been renamed to setSolver and
  1962 addSolver; added safe_asm_full_simp_tac;
  1963 
  1964 
  1965 *** HOL ***
  1966 
  1967 * a generic induction tactic `induct_tac' which works for all datatypes and
  1968 also for type `nat';
  1969 
  1970 * a generic case distinction tactic `exhaust_tac' which works for all
  1971 datatypes and also for type `nat';
  1972 
  1973 * each datatype comes with a function `size';
  1974 
  1975 * patterns in case expressions allow tuple patterns as arguments to
  1976 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1977 
  1978 * primrec now also works with type nat;
  1979 
  1980 * recdef: a new declaration form, allows general recursive functions to be
  1981 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1982 
  1983 * the constant for negation has been renamed from "not" to "Not" to
  1984 harmonize with FOL, ZF, LK, etc.;
  1985 
  1986 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1987 infinite lists;
  1988 
  1989 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1990 
  1991 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1992 problems in commutative rings, using axiomatic type classes for + and *;
  1993 
  1994 * more examples in HOL/MiniML and HOL/Auth;
  1995 
  1996 * more default rewrite rules for quantifiers, union/intersection;
  1997 
  1998 * a new constant `arbitrary == @x.False';
  1999 
  2000 * HOLCF/IOA replaces old HOL/IOA;
  2001 
  2002 * HOLCF changes: derived all rules and arities
  2003   + axiomatic type classes instead of classes
  2004   + typedef instead of faking type definitions
  2005   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2006   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2007   + eliminated the types void, one, tr
  2008   + use unit lift and bool lift (with translations) instead of one and tr
  2009   + eliminated blift from Lift3.thy (use Def instead of blift)
  2010   all eliminated rules are derived as theorems --> no visible changes ;
  2011 
  2012 
  2013 *** ZF ***
  2014 
  2015 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2016 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2017 as ZF_cs addSIs [equalityI];
  2018 
  2019 
  2020 
  2021 New in Isabelle94-7 (November 96)
  2022 ---------------------------------
  2023 
  2024 * allowing negative levels (as offsets) in prlev and choplev;
  2025 
  2026 * super-linear speedup for large simplifications;
  2027 
  2028 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2029 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2030 FAIL); can suppress it using the command Delsimps (ex_simps @
  2031 all_simps); De Morgan laws are also now included, by default;
  2032 
  2033 * improved printing of ==>  :  ~:
  2034 
  2035 * new object-logic "Sequents" adds linear logic, while replacing LK
  2036 and Modal (thanks to Sara Kalvala);
  2037 
  2038 * HOL/Auth: correctness proofs for authentication protocols;
  2039 
  2040 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2041 examples on HOL/Auth);
  2042 
  2043 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2044 the rewriter and classical reasoner simultaneously;
  2045 
  2046 * function uresult no longer returns theorems in "standard" format;
  2047 regain previous version by: val uresult = standard o uresult;
  2048 
  2049 
  2050 
  2051 New in Isabelle94-6
  2052 -------------------
  2053 
  2054 * oracles -- these establish an interface between Isabelle and trusted
  2055 external reasoners, which may deliver results as theorems;
  2056 
  2057 * proof objects (in particular record all uses of oracles);
  2058 
  2059 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2060 
  2061 * "constdefs" section in theory files;
  2062 
  2063 * "primrec" section (HOL) no longer requires names;
  2064 
  2065 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2066 
  2067 
  2068 
  2069 New in Isabelle94-5
  2070 -------------------
  2071 
  2072 * reduced space requirements;
  2073 
  2074 * automatic HTML generation from theories;
  2075 
  2076 * theory files no longer require "..." (quotes) around most types;
  2077 
  2078 * new examples, including two proofs of the Church-Rosser theorem;
  2079 
  2080 * non-curried (1994) version of HOL is no longer distributed;
  2081 
  2082 
  2083 
  2084 New in Isabelle94-4
  2085 -------------------
  2086 
  2087 * greatly reduced space requirements;
  2088 
  2089 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2090 
  2091 * searchable theorem database (see the section "Retrieving theorems" on
  2092 page 8 of the Reference Manual);
  2093 
  2094 * new examples, including Grabczewski's monumental case study of the
  2095 Axiom of Choice;
  2096 
  2097 * The previous version of HOL renamed to Old_HOL;
  2098 
  2099 * The new version of HOL (previously called CHOL) uses a curried syntax
  2100 for functions.  Application looks like f a b instead of f(a,b);
  2101 
  2102 * Mutually recursive inductive definitions finally work in HOL;
  2103 
  2104 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2105 translates to the operator "split";
  2106 
  2107 
  2108 
  2109 New in Isabelle94-3
  2110 -------------------
  2111 
  2112 * new infix operator, addss, allowing the classical reasoner to
  2113 perform simplification at each step of its search.  Example:
  2114         fast_tac (cs addss ss)
  2115 
  2116 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2117 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2118 look like (a,b) instead of <a,b>;
  2119 
  2120 * PLEASE NOTE: CHOL will eventually replace HOL!
  2121 
  2122 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2123 It translates to the operator "split".  A new theory of integers is available;
  2124 
  2125 * In ZF, integer numerals now denote two's-complement binary integers.
  2126 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2127 
  2128 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2129 of the Axiom of Choice;
  2130 
  2131 
  2132 
  2133 New in Isabelle94-2
  2134 -------------------
  2135 
  2136 * Significantly faster resolution;
  2137 
  2138 * the different sections in a .thy file can now be mixed and repeated
  2139 freely;
  2140 
  2141 * Database of theorems for FOL, HOL and ZF.  New
  2142 commands including qed, qed_goal and bind_thm store theorems in the database.
  2143 
  2144 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2145 a given theory (thms_of), or find out what theory a theorem was proved in
  2146 (theory_of_thm);
  2147 
  2148 * Bugs fixed in the inductive definition and datatype packages;
  2149 
  2150 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2151 and HOL_dup_cs obsolete;
  2152 
  2153 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2154 have been removed;
  2155 
  2156 * Simpler definition of function space in ZF;
  2157 
  2158 * new results about cardinal and ordinal arithmetic in ZF;
  2159 
  2160 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2161 types;
  2162 
  2163 
  2164 $Id$