NEWS
author wenzelm
Mon Dec 10 20:57:44 2001 +0100 (2001-12-10)
changeset 12457 cbfc53e45476
parent 12405 9b16f99fd7b9
child 12467 b5630a4ea5d8
permissions -rw-r--r--
* HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
of "lam" -- INCOMPATIBILITY;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     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;
    31 
    32 
    33 *** Isar ***
    34 
    35 * Pure/Provers: improved proof by cases and induction;
    36   - 'case' command admits impromptu naming of parameters (such as
    37     "case (Suc n)");
    38   - 'induct' method divinates rule instantiation from the inductive
    39     claim; no longer requires excessive ?P bindings for proper
    40     instantiation of cases;
    41   - 'induct' method properly enumerates all possibilities of set/type
    42     rules; as a consequence facts may be also passed through *type*
    43     rules without further ado;
    44   - 'induct' method now derives symbolic cases from the *rulified*
    45     rule (before it used to rulify cases stemming from the internal
    46     atomized version); this means that the context of a non-atomic
    47     statement becomes is included in the hypothesis, avoiding the
    48     slightly cumbersome show "PROP ?case" form;
    49   - 'induct' may now use elim-style induction rules without chaining
    50     facts, using ``missing'' premises from the goal state; this allows
    51     rules stemming from inductive sets to be applied in unstructured
    52     scripts, while still benefitting from proper handling of non-atomic
    53     statements; NB: major inductive premises need to be put first, all
    54     the rest of the goal is passed through the induction;
    55   - 'induct' proper support for mutual induction involving non-atomic
    56     rule statements (uses the new concept of simultaneous goals, see
    57     below);
    58   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    59   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    60   - moved induct/cases attributes to Pure, methods to Provers;
    61   - generic method setup instantiated for FOL and HOL;
    62 
    63 * Pure: support multiple simultaneous goal statements, for example
    64 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    65 meta-level mechanism, this acts as if several individual goals had
    66 been stated separately; in particular common proof methods need to be
    67 repeated in order to cover all claims; note that a single elimination
    68 step is *not* sufficient to establish the two conjunctions, so this
    69 fails:
    70 
    71   assume "A & B" then have A and B ..   (*".." fails*)
    72 
    73 better use "obtain" in situations as above; alternative refer to
    74 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    75 
    76 * Pure: proper integration with ``locales''; unlike the original
    77 version by Florian Kammüller, Isar locales package high-level proof
    78 contexts rather than raw logical ones (e.g. we admit to include
    79 attributes everywhere); operations on locales include merge and
    80 rename; e.g. see HOL/ex/Locales.thy;
    81 
    82 * Pure: theory goals now support ad-hoc contexts, which are discharged
    83 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    84 coincides with that of a locale body;
    85 
    86 * Pure: renamed "antecedent" case to "rule_context";
    87 
    88 * Pure: added 'corollary' command;
    89 
    90 * Pure: fixed 'token_translation' command;
    91 
    92 * Pure: removed obsolete 'exported' attribute;
    93 
    94 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    95 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    96 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    97 
    98 * Pure: method 'atomize' presents local goal premises as object-level
    99 statements (atomic meta-level propositions); setup controlled via
   100 rewrite rules declarations of 'atomize' attribute; example
   101 application: 'induct' method with proper rule statements in improper
   102 proof *scripts*;
   103 
   104 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   105 now consider the syntactic context of assumptions, giving a better
   106 chance to get type-inference of the arguments right (this is
   107 especially important for locales);
   108 
   109 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   110 mode;
   111 
   112 * Pure/obtain: the formal conclusion "thesis", being marked as
   113 ``internal'', may no longer be reference directly in the text;
   114 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   115 situations;
   116 
   117 * Pure: generic 'sym' attribute which declares a rule both as pure
   118 'elim?' and for the 'symmetric' operation;
   119 
   120 * Pure/Provers/classical: simplified integration with pure rule
   121 attributes and methods; the classical "intro?/elim?/dest?"
   122 declarations coincide with the pure ones; the "rule" method no longer
   123 includes classically swapped intros; "intro" and "elim" methods no
   124 longer pick rules from the context; also got rid of ML declarations
   125 AddXIs/AddXEs/AddXDs; all of this has some potential for
   126 INCOMPATIBILITY;
   127 
   128 * Provers/classical: attribute 'swapped' produces classical inversions
   129 of introduction rules;
   130 
   131 * Provers/simplifier: 'simplified' attribute may refer to explicit
   132 rules instead of full simplifier context; 'iff' attribute handles
   133 conditional rules;
   134 
   135 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   136 
   137 * HOL: 'recdef' now fails on unfinished automated proofs, use
   138 "(permissive)" option to recover old behavior;
   139 
   140 * HOL: 'inductive' no longer features separate (collective) attributes
   141 for 'intros' (was found too confusing);
   142 
   143 * HOL: properly declared induction rules less_induct and
   144 wf_induct_rule;
   145 
   146 * HOLCF: domain package adapted to new-style theories, e.g. see
   147 HOLCF/ex/Dnat.thy;
   148 
   149 * ZF: proper integration of logic-specific tools and packages,
   150 including theory commands '(co)inductive', '(co)datatype',
   151 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   152 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   153 
   154 
   155 *** HOL ***
   156 
   157 * HOL: moved over to sane numeral syntax; the new policy is as
   158 follows:
   159 
   160   - 0 and 1 are polymorphic constants, which are defined on any
   161   numeric type (nat, int, real etc.);
   162 
   163   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   164   binary representation internally;
   165 
   166   - type nat has special constructor Suc, and generally prefers Suc 0
   167   over 1::nat and Suc (Suc 0) over 2::nat;
   168 
   169 This change may cause significant problems of INCOMPATIBILITY; here
   170 are some hints on converting existing sources:
   171 
   172   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   173   entities, so expressions involving "-" (unary or binary minus) need
   174   to be spaced properly;
   175 
   176   - existing occurrences of "1" may need to be constraint "1::nat" or
   177   even replaced by Suc 0; similar for old "2";
   178 
   179   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   180 
   181   - remove all special provisions on numerals in proofs;
   182 
   183 * HOL: the class of all HOL types is now called "type" rather than
   184 "term"; INCOMPATIBILITY, need to adapt references to this type class
   185 in axclass/classes, instance/arities, and (usually rare) occurrences
   186 in typings (of consts etc.); internally the class is called
   187 "HOL.type", ML programs should refer to HOLogic.typeS;
   188 
   189 * HOL/record package improvements:
   190   - new derived operations "fields" to build a partial record section,
   191     "extend" to promote a fixed record to a record scheme, and
   192     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   193     declared as simp by default;
   194   - removed "make_scheme" operations (use "make" with "extend") --
   195     INCOMPATIBILITY;
   196   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   197   - provides cases/induct rules for use with corresponding Isar
   198     methods (for concrete records, record schemes, concrete more
   199     parts, and schematic more parts -- in that order);
   200   - internal definitions directly based on a light-weight abstract
   201     theory of product types over typedef rather than datatype;
   202 
   203 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   204 
   205 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   206 (beware of argument permutation!);
   207 
   208 * HOL: linorder_less_split superseded by linorder_cases;
   209 
   210 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   211 to peripheral theory "Hilbert_Choice";
   212 
   213 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   214 in this (rare) case use:
   215 
   216   delSWrapper "split_all_tac"
   217   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   218 
   219 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   220 MAY FAIL;
   221 
   222 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   223 Isabelle's type classes, ^ on functions and relations has too general
   224 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   225 necessary to attach explicit type constraints;
   226 
   227 * HOL: syntax translations now work properly with numerals and records
   228 expressions;
   229 
   230 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   231 of "lam" -- INCOMPATIBILITY;
   232 
   233 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   234 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   235 renamed "Product_Type.unit";
   236 
   237 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   238 Florian Kammüller;
   239 
   240 
   241 *** HOLCF ***
   242 
   243 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
   244 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   245 lift.induct_tac, always use UU instead of Undef;
   246 
   247 
   248 *** ZF ***
   249 
   250 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   251 typeless version of the formalism;
   252 
   253 * ZF/Induct: new directory for examples of inductive definitions,
   254 including theory Multiset for multiset orderings;
   255 
   256 * ZF: the integer library now covers quotients and remainders, with
   257 many laws relating division to addition, multiplication, etc.;
   258 
   259 
   260 *** General ***
   261 
   262 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   263 variable proof controls level of detail: 0 = no proofs (only oracle
   264 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   265 also ref manual for further ML interfaces;
   266 
   267 * Pure/axclass: removed obsolete ML interface
   268 goal_subclass/goal_arity;
   269 
   270 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   271 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   272 separate tokens, so expressions involving minus need to be spaced
   273 properly;
   274 
   275 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   276 rather than "infixl" or "infixr";
   277 
   278 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   279 sort constraint specifications in type inference; e.g. "x::_::foo"
   280 ensures that the type of "x" is of sort "foo" (but not necessarily a
   281 type variable);
   282 
   283 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   284 control output of nested => (types); the default behavior is
   285 "type_brackets";
   286 
   287 * Pure/syntax: builtin parse translation for "_constify" turns valued
   288 tokens into AST constants;
   289 
   290 * Pure/syntax: prefer later declarations of translations and print
   291 translation functions; potential INCOMPATIBILITY: need to reverse
   292 multiple declarations for same syntax element constant;
   293 
   294 * Provers/classical: renamed addaltern to addafter, addSaltern to
   295 addSafter;
   296 
   297 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   298 as well;
   299 
   300 * system: refrain from any attempt at filtering input streams; no
   301 longer support ``8bit'' encoding of old isabelle font, instead proper
   302 iso-latin characters may now be used;
   303 
   304 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   305 
   306 * system: Proof General keywords specification is now part of the
   307 Isabelle distribution (see etc/isar-keywords.el);
   308 
   309 * system: smart selection of Isabelle process versus Isabelle
   310 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   311 run both "isabelle" and "Isabelle" even if file names are badly
   312 damaged (executable inspects the case of the first letter of its own
   313 name); added separate "isabelle-process" and "isabelle-interface";
   314 
   315 
   316 
   317 New in Isabelle99-2 (February 2001)
   318 -----------------------------------
   319 
   320 *** Overview of INCOMPATIBILITIES ***
   321 
   322 * HOL: please note that theories in the Library and elsewhere often use the
   323 new-style (Isar) format; to refer to their theorems in an ML script you must
   324 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   325 
   326 * HOL: inductive package no longer splits induction rule aggressively,
   327 but only as far as specified by the introductions given; the old
   328 format may be recovered via ML function complete_split_rule or attribute
   329 'split_rule (complete)';
   330 
   331 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   332 gfp_Tarski to gfp_unfold;
   333 
   334 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   335 
   336 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   337 relation); infix "^^" has been renamed "``"; infix "``" has been
   338 renamed "`"; "univalent" has been renamed "single_valued";
   339 
   340 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   341 operation;
   342 
   343 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   344 
   345 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   346 
   347 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   348 consequence, it is no longer monotonic wrt. the local goal context
   349 (which is now passed through the inductive cases);
   350 
   351 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   352 \<gg> to \<ggreater>;
   353 
   354 
   355 *** Document preparation ***
   356 
   357 * \isabellestyle{NAME} selects version of Isabelle output (currently
   358 available: are "it" for near math-mode best-style output, "sl" for
   359 slanted text style, and "tt" for plain type-writer; if no
   360 \isabellestyle command is given, output is according to slanted
   361 type-writer);
   362 
   363 * support sub/super scripts (for single symbols only), input syntax is
   364 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   365 
   366 * some more standard symbols; see Appendix A of the system manual for
   367 the complete list of symbols defined in isabellesym.sty;
   368 
   369 * improved isabelle style files; more abstract symbol implementation
   370 (should now use \isamath{...} and \isatext{...} in custom symbol
   371 definitions);
   372 
   373 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   374 state; Note that presentation of goal states does not conform to
   375 actual human-readable proof documents.  Please do not include goal
   376 states into document output unless you really know what you are doing!
   377 
   378 * proper indentation of antiquoted output with proportional LaTeX
   379 fonts;
   380 
   381 * no_document ML operator temporarily disables LaTeX document
   382 generation;
   383 
   384 * isatool unsymbolize tunes sources for plain ASCII communication;
   385 
   386 
   387 *** Isar ***
   388 
   389 * Pure: Isar now suffers initial goal statements to contain unbound
   390 schematic variables (this does not conform to actual readable proof
   391 documents, due to unpredictable outcome and non-compositional proof
   392 checking); users who know what they are doing may use schematic goals
   393 for Prolog-style synthesis of proven results;
   394 
   395 * Pure: assumption method (an implicit finishing) now handles actual
   396 rules as well;
   397 
   398 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   399 initial goal, declare "that" only as Pure intro (only for single
   400 steps); the "that" rule assumption may now be involved in implicit
   401 finishing, thus ".." becomes a feasible for trivial obtains;
   402 
   403 * Pure: default proof step now includes 'intro_classes'; thus trivial
   404 instance proofs may be performed by "..";
   405 
   406 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   407 statements as well;
   408 
   409 * Pure: more robust selection of calculational rules;
   410 
   411 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   412 rule (as well as the assumption rule);
   413 
   414 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   415 lemmas, using the graph browser tool;
   416 
   417 * Pure: predict failure of "show" in interactive mode;
   418 
   419 * Pure: 'thms_containing' now takes actual terms as arguments;
   420 
   421 * HOL: improved method 'induct' --- now handles non-atomic goals
   422 (potential INCOMPATIBILITY); tuned error handling;
   423 
   424 * HOL: cases and induct rules now provide explicit hints about the
   425 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   426 any remaining facts are inserted into the goal verbatim;
   427 
   428 * HOL: local contexts (aka cases) may now contain term bindings as
   429 well; the 'cases' and 'induct' methods new provide a ?case binding for
   430 the result to be shown in each case;
   431 
   432 * HOL: added 'recdef_tc' command;
   433 
   434 * isatool convert assists in eliminating legacy ML scripts;
   435 
   436 
   437 *** HOL ***
   438 
   439 * HOL/Library: a collection of generic theories to be used together
   440 with main HOL; the theory loader path already includes this directory
   441 by default; the following existing theories have been moved here:
   442 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   443 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   444 
   445 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   446 modelling and verification task performed in Isabelle/HOL +
   447 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   448 
   449 * HOL/Algebra: special summation operator SUM no longer exists, it has
   450 been replaced by setsum; infix 'assoc' now has priority 50 (like
   451 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   452 'domain', this makes the theory consistent with mathematical
   453 literature;
   454 
   455 * HOL basics: added overloaded operations "inverse" and "divide"
   456 (infix "/"), syntax for generic "abs" operation, generic summation
   457 operator \<Sum>;
   458 
   459 * HOL/typedef: simplified package, provide more useful rules (see also
   460 HOL/subset.thy);
   461 
   462 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   463 now expressed as a proper nested rule (old-style tactic scripts may
   464 require atomize_strip_tac to cope with non-atomic premises);
   465 
   466 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   467 to "split_conv" (old name still available for compatibility);
   468 
   469 * HOL: improved concrete syntax for strings (e.g. allows translation
   470 rules with string literals);
   471 
   472 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   473  and Fleuriot's mechanization of analysis, including the transcendental
   474  functions for the reals;
   475 
   476 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   477 
   478 
   479 *** CTT ***
   480 
   481 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   482 "lam" is displayed as TWO lambda-symbols
   483 
   484 * CTT: theory Main now available, containing everything (that is, Bool
   485 and Arith);
   486 
   487 
   488 *** General ***
   489 
   490 * Pure: the Simplifier has been implemented properly as a derived rule
   491 outside of the actual kernel (at last!); the overall performance
   492 penalty in practical applications is about 50%, while reliability of
   493 the Isabelle inference kernel has been greatly improved;
   494 
   495 * print modes "brackets" and "no_brackets" control output of nested =>
   496 (types) and ==> (props); the default behaviour is "brackets";
   497 
   498 * Provers: fast_tac (and friends) now handle actual object-logic rules
   499 as assumptions as well;
   500 
   501 * system: support Poly/ML 4.0;
   502 
   503 * system: isatool install handles KDE version 1 or 2;
   504 
   505 
   506 
   507 New in Isabelle99-1 (October 2000)
   508 ----------------------------------
   509 
   510 *** Overview of INCOMPATIBILITIES ***
   511 
   512 * HOL: simplification of natural numbers is much changed; to partly
   513 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   514 issue the following ML commands:
   515 
   516   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   517   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   518 
   519 * HOL: simplification no longer dives into case-expressions; this is
   520 controlled by "t.weak_case_cong" for each datatype t;
   521 
   522 * HOL: nat_less_induct renamed to less_induct;
   523 
   524 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   525 fixsome to patch .thy and .ML sources automatically;
   526 
   527   select_equality  -> some_equality
   528   select_eq_Ex     -> some_eq_ex
   529   selectI2EX       -> someI2_ex
   530   selectI2         -> someI2
   531   selectI          -> someI
   532   select1_equality -> some1_equality
   533   Eps_sym_eq       -> some_sym_eq_trivial
   534   Eps_eq           -> some_eq_trivial
   535 
   536 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   537 
   538 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   539 instead);
   540 
   541 * HOL: the recursion equations generated by 'recdef' are now called
   542 f.simps instead of f.rules;
   543 
   544 * HOL: qed_spec_mp now also handles bounded ALL as well;
   545 
   546 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   547 sometimes be needed;
   548 
   549 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   550 
   551 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   552 
   553 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   554 product is now "<*>" instead of "Times"; the lexicographic product is
   555 now "<*lex*>" instead of "**";
   556 
   557 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   558 of main HOL, but was unused); better use HOL's datatype package;
   559 
   560 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   561 the old syntax may be recovered as follows:
   562 
   563   syntax (symbols)
   564     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   565       (infixl "\\<oplus>" 100)
   566 
   567 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   568 
   569 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   570 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   571 internally;
   572 
   573 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   574 changed from A/r to A//r;
   575 
   576 * ZF: new treatment of arithmetic (nat & int) may break some old
   577 proofs;
   578 
   579 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   580 rulify -> rule_format, elimify -> elim_format, ...);
   581 
   582 * Isar/Provers: intro/elim/dest attributes changed; renamed
   583 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   584 should have to change intro!! to intro? only); replaced "delrule" by
   585 "rule del";
   586 
   587 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   588 
   589 * Provers: strengthened force_tac by using new first_best_tac;
   590 
   591 * LaTeX document preparation: several changes of isabelle.sty (see
   592 lib/texinputs);
   593 
   594 
   595 *** Document preparation ***
   596 
   597 * formal comments (text blocks etc.) in new-style theories may now
   598 contain antiquotations of thm/prop/term/typ/text to be presented
   599 according to latex print mode; concrete syntax is like this:
   600 @{term[show_types] "f(x) = a + x"};
   601 
   602 * isatool mkdir provides easy setup of Isabelle session directories,
   603 including proper document sources;
   604 
   605 * generated LaTeX sources are now deleted after successful run
   606 (isatool document -c); may retain a copy somewhere else via -D option
   607 of isatool usedir;
   608 
   609 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   610 style files, achieving self-contained LaTeX sources and simplifying
   611 LaTeX debugging;
   612 
   613 * old-style theories now produce (crude) LaTeX output as well;
   614 
   615 * browser info session directories are now self-contained (may be put
   616 on WWW server seperately); improved graphs of nested sessions; removed
   617 graph for 'all sessions';
   618 
   619 * several improvements in isabelle style files; \isabellestyle{it}
   620 produces fake math mode output; \isamarkupheader is now \section by
   621 default; see lib/texinputs/isabelle.sty etc.;
   622 
   623 
   624 *** Isar ***
   625 
   626 * Isar/Pure: local results and corresponding term bindings are now
   627 subject to Hindley-Milner polymorphism (similar to ML); this
   628 accommodates incremental type-inference very nicely;
   629 
   630 * Isar/Pure: new derived language element 'obtain' supports
   631 generalized existence reasoning;
   632 
   633 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   634 support accumulation of results, without applying any rules yet;
   635 useful to collect intermediate results without explicit name
   636 references, and for use with transitivity rules with more than 2
   637 premises;
   638 
   639 * Isar/Pure: scalable support for case-analysis type proofs: new
   640 'case' language element refers to local contexts symbolically, as
   641 produced by certain proof methods; internally, case names are attached
   642 to theorems as "tags";
   643 
   644 * Isar/Pure: theory command 'hide' removes declarations from
   645 class/type/const name spaces;
   646 
   647 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   648 indicate potential overloading;
   649 
   650 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   651 
   652 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   653 "{a,b,c}" instead of {a,b,c};
   654 
   655 * Isar/Pure now provides its own version of intro/elim/dest
   656 attributes; useful for building new logics, but beware of confusion
   657 with the version in Provers/classical;
   658 
   659 * Isar/Pure: the local context of (non-atomic) goals is provided via
   660 case name 'antecedent';
   661 
   662 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   663 to the current context is now done automatically);
   664 
   665 * Isar/Pure: theory command 'method_setup' provides a simple interface
   666 for definining proof methods in ML;
   667 
   668 * Isar/Provers: intro/elim/dest attributes changed; renamed
   669 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   670 most cases, one should have to change intro!! to intro? only);
   671 replaced "delrule" by "rule del";
   672 
   673 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   674 'symmetric' attribute (the latter supercedes [RS sym]);
   675 
   676 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   677 method modifier); 'simp' method: 'only:' modifier removes loopers as
   678 well (including splits);
   679 
   680 * Isar/Provers: Simplifier and Classical methods now support all kind
   681 of modifiers used in the past, including 'cong', 'iff', etc.
   682 
   683 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   684 of Simplifier and Classical reasoner);
   685 
   686 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   687 now support named cases; major packages (inductive, datatype, primrec,
   688 recdef) support case names and properly name parameters;
   689 
   690 * Isar/HOL: new transitivity rules for substitution in inequalities --
   691 monotonicity conditions are extracted to be proven at end of
   692 calculations;
   693 
   694 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   695 method anyway;
   696 
   697 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   698 split_if split_if_asm; datatype package provides theorems foo.splits =
   699 foo.split foo.split_asm for each datatype;
   700 
   701 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   702 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   703 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   704 use "(cases (simplified))" method in proper proof texts);
   705 
   706 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   707 
   708 * Isar: names of theorems etc. may be natural numbers as well;
   709 
   710 * Isar: 'pr' command: optional arguments for goals_limit and
   711 ProofContext.prems_limit; no longer prints theory contexts, but only
   712 proof states;
   713 
   714 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   715 additional print modes to be specified; e.g. "pr(latex)" will print
   716 proof state according to the Isabelle LaTeX style;
   717 
   718 * Isar: improved support for emulating tactic scripts, including proof
   719 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   720 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   721 (for HOL datatypes);
   722 
   723 * Isar: simplified (more robust) goal selection of proof methods: 1st
   724 goal, all goals, or explicit goal specifier (tactic emulation); thus
   725 'proof method scripts' have to be in depth-first order;
   726 
   727 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   728 
   729 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   730 should instead use individual commands for printing items
   731 (print_commands, print_methods etc.);
   732 
   733 * Isar: added 'nothing' --- the empty list of theorems;
   734 
   735 
   736 *** HOL ***
   737 
   738 * HOL/MicroJava: formalization of a fragment of Java, together with a
   739 corresponding virtual machine and a specification of its bytecode
   740 verifier and a lightweight bytecode verifier, including proofs of
   741 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   742 Cornelia Pusch (see also the homepage of project Bali at
   743 http://isabelle.in.tum.de/Bali/);
   744 
   745 * HOL/Algebra: new theory of rings and univariate polynomials, by
   746 Clemens Ballarin;
   747 
   748 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   749 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   750 Rasmussen;
   751 
   752 * HOL/Lattice: fundamental concepts of lattice theory and order
   753 structures, including duals, properties of bounds versus algebraic
   754 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   755 Theorem for complete lattices etc.; may also serve as a demonstration
   756 for abstract algebraic reasoning using axiomatic type classes, and
   757 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   758 
   759 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   760 von Oheimb;
   761 
   762 * HOL/IMPP: extension of IMP with local variables and mutually
   763 recursive procedures, by David von Oheimb;
   764 
   765 * HOL/Lambda: converted into new-style theory and document;
   766 
   767 * HOL/ex/Multiquote: example of multiple nested quotations and
   768 anti-quotations -- basically a generalized version of de-Bruijn
   769 representation; very useful in avoiding lifting of operations;
   770 
   771 * HOL/record: added general record equality rule to simpset; fixed
   772 select-update simplification procedure to handle extended records as
   773 well; admit "r" as field name;
   774 
   775 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   776 other numeric types and also as the identity of groups, rings, etc.;
   777 
   778 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   779 Types nat and int belong to this axclass;
   780 
   781 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   782    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   783    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   784   two terms #m*u and #n*u are replaced by #(m+n)*u
   785     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   786   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   787     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   788 
   789 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   790 powerful prover for predicate logic but knows nothing of clasets; see
   791 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   792 
   793 * HOL: new version of "case_tac" subsumes both boolean case split and
   794 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   795 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   796 
   797 * HOL: simplification no longer dives into case-expressions: only the
   798 selector expression is simplified, but not the remaining arms; to
   799 enable full simplification of case-expressions for datatype t, you may
   800 remove t.weak_case_cong from the simpset, either globally (Delcongs
   801 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   802 
   803 * HOL/recdef: the recursion equations generated by 'recdef' for
   804 function 'f' are now called f.simps instead of f.rules; if all
   805 termination conditions are proved automatically, these simplification
   806 rules are added to the simpset, as in primrec; rules may be named
   807 individually as well, resulting in a separate list of theorems for
   808 each equation;
   809 
   810 * HOL/While is a new theory that provides a while-combinator. It
   811 permits the definition of tail-recursive functions without the
   812 provision of a termination measure. The latter is necessary once the
   813 invariant proof rule for while is applied.
   814 
   815 * HOL: new (overloaded) notation for the set of elements below/above
   816 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   817 
   818 * HOL: theorems impI, allI, ballI bound as "strip";
   819 
   820 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   821 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   822 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   823 
   824 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   825 
   826 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   827 main HOL, but was unused);
   828 
   829 * HOL: fewer consts declared as global (e.g. have to refer to
   830 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   831 
   832 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   833 in case of overlap with user translations (e.g. judgements over
   834 tuples); (note that the underlying logical represenation is still
   835 bogus);
   836 
   837 
   838 *** ZF ***
   839 
   840 * ZF: simplification automatically cancels common terms in arithmetic
   841 expressions over nat and int;
   842 
   843 * ZF: new treatment of nat to minimize type-checking: all operators
   844 coerce their operands to a natural number using the function natify,
   845 making the algebraic laws unconditional;
   846 
   847 * ZF: as above, for int: operators coerce their operands to an integer
   848 using the function intify;
   849 
   850 * ZF: the integer library now contains many of the usual laws for the
   851 orderings, including $<=, and monotonicity laws for $+ and $*;
   852 
   853 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   854 simplification;
   855 
   856 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   857 to the simplifier and classical reasoner simultaneously;
   858 
   859 
   860 *** General ***
   861 
   862 * Provers: blast_tac now handles actual object-logic rules as
   863 assumptions; note that auto_tac uses blast_tac internally as well;
   864 
   865 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   866 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   867 
   868 * Provers: delrules now handles destruct rules as well (no longer need
   869 explicit make_elim);
   870 
   871 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   872   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   873 use instead the strong form,
   874   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   875 in HOL, FOL and ZF the function cla_make_elim will create such rules
   876 from destruct-rules;
   877 
   878 * Provers: Simplifier.easy_setup provides a fast path to basic
   879 Simplifier setup for new object-logics;
   880 
   881 * Pure: AST translation rules no longer require constant head on LHS;
   882 
   883 * Pure: improved name spaces: ambiguous output is qualified; support
   884 for hiding of names;
   885 
   886 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   887 XSYMBOL_HOME; no longer need to do manual configuration in most
   888 situations;
   889 
   890 * system: compression of ML heaps images may now be controlled via -c
   891 option of isabelle and isatool usedir (currently only observed by
   892 Poly/ML);
   893 
   894 * system: isatool installfonts may handle X-Symbol fonts as well (very
   895 useful for remote X11);
   896 
   897 * system: provide TAGS file for Isabelle sources;
   898 
   899 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   900 order;
   901 
   902 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   903 timing flag supersedes proof_timing and Toplevel.trace;
   904 
   905 * ML: new combinators |>> and |>>> for incremental transformations
   906 with secondary results (e.g. certain theory extensions):
   907 
   908 * ML: PureThy.add_defs gets additional argument to indicate potential
   909 overloading (usually false);
   910 
   911 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   912 results;
   913 
   914 
   915 
   916 New in Isabelle99 (October 1999)
   917 --------------------------------
   918 
   919 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   920 
   921 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   922 are no longer simplified.  (This allows the simplifier to unfold recursive
   923 functional programs.)  To restore the old behaviour, declare
   924 
   925     Delcongs [if_weak_cong];
   926 
   927 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   928 complement;
   929 
   930 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   931 
   932 * HOL/datatype: mutual_induct_tac no longer exists --
   933   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   934 
   935 * HOL/typedef: fixed type inference for representing set; type
   936 arguments now have to occur explicitly on the rhs as type constraints;
   937 
   938 * ZF: The con_defs part of an inductive definition may no longer refer
   939 to constants declared in the same theory;
   940 
   941 * HOL, ZF: the function mk_cases, generated by the inductive
   942 definition package, has lost an argument.  To simplify its result, it
   943 uses the default simpset instead of a supplied list of theorems.
   944 
   945 * HOL/List: the constructors of type list are now Nil and Cons;
   946 
   947 * Simplifier: the type of the infix ML functions
   948         setSSolver addSSolver setSolver addSolver
   949 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   950 for packaging solvers. A solver is created via
   951         mk_solver: string -> (thm list -> int -> tactic) -> solver
   952 where the string argument is only a comment.
   953 
   954 
   955 *** Proof tools ***
   956 
   957 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   958 decision procedure for linear arithmetic. Currently it is used for
   959 types `nat', `int', and `real' in HOL (see below); it can, should and
   960 will be instantiated for other types and logics as well.
   961 
   962 * The simplifier now accepts rewrite rules with flexible heads, eg
   963      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   964   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   965   matching.
   966 
   967 
   968 *** General ***
   969 
   970 * New Isabelle/Isar subsystem provides an alternative to traditional
   971 tactical theorem proving; together with the ProofGeneral/isar user
   972 interface it offers an interactive environment for developing human
   973 readable proof documents (Isar == Intelligible semi-automated
   974 reasoning); for further information see isatool doc isar-ref,
   975 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   976 
   977 * improved and simplified presentation of theories: better HTML markup
   978 (including colors), graph views in several sizes; isatool usedir now
   979 provides a proper interface for user theories (via -P option); actual
   980 document preparation based on (PDF)LaTeX is available as well (for
   981 new-style theories only); see isatool doc system for more information;
   982 
   983 * native support for Proof General, both for classic Isabelle and
   984 Isabelle/Isar;
   985 
   986 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   987 using the graph browser tool;
   988 
   989 * Isabelle manuals now also available as PDF;
   990 
   991 * theory loader rewritten from scratch (may not be fully
   992 bug-compatible); old loadpath variable has been replaced by show_path,
   993 add_path, del_path, reset_path functions; new operations such as
   994 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   995 isatool doc ref);
   996 
   997 * improved isatool install: option -k creates KDE application icon,
   998 option -p DIR installs standalone binaries;
   999 
  1000 * added ML_PLATFORM setting (useful for cross-platform installations);
  1001 more robust handling of platform specific ML images for SML/NJ;
  1002 
  1003 * the settings environment is now statically scoped, i.e. it is never
  1004 created again in sub-processes invoked from isabelle, isatool, or
  1005 Isabelle;
  1006 
  1007 * path element specification '~~' refers to '$ISABELLE_HOME';
  1008 
  1009 * in locales, the "assumes" and "defines" parts may be omitted if
  1010 empty;
  1011 
  1012 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1013 long arrows);
  1014 
  1015 * new print_mode "HTML";
  1016 
  1017 * new flag show_tags controls display of tags of theorems (which are
  1018 basically just comments that may be attached by some tools);
  1019 
  1020 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1021 mode and goal output format:
  1022 
  1023 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1024 244c244
  1025 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1026 ---
  1027 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1028 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1029 181c181
  1030 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1031 ---
  1032 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1033 
  1034 * function bind_thms stores lists of theorems (cf. bind_thm);
  1035 
  1036 * new shorthand tactics ftac, eatac, datac, fatac;
  1037 
  1038 * qed (and friends) now accept "" as result name; in that case the
  1039 theorem is not stored, but proper checks and presentation of the
  1040 result still apply;
  1041 
  1042 * theorem database now also indexes constants "Trueprop", "all",
  1043 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1044 
  1045 
  1046 *** HOL ***
  1047 
  1048 ** HOL arithmetic **
  1049 
  1050 * There are now decision procedures for linear arithmetic over nat and
  1051 int:
  1052 
  1053 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1054 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1055 are treated as atomic; subformulae not involving type `nat' or `int'
  1056 are ignored; quantified subformulae are ignored unless they are
  1057 positive universal or negative existential. The tactic has to be
  1058 invoked by hand and can be a little bit slow. In particular, the
  1059 running time is exponential in the number of occurrences of `min' and
  1060 `max', and `-' on `nat'.
  1061 
  1062 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1063 (negated) (in)equalities among the premises and the conclusion into
  1064 account (i.e. no compound formulae) and does not know about `min' and
  1065 `max', and `-' on `nat'. It is fast and is used automatically by the
  1066 simplifier.
  1067 
  1068 NB: At the moment, these decision procedures do not cope with mixed
  1069 nat/int formulae where the two parts interact, such as `m < n ==>
  1070 int(m) < int(n)'.
  1071 
  1072 * HOL/Numeral provides a generic theory of numerals (encoded
  1073 efficiently as bit strings); setup for types nat/int/real is in place;
  1074 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1075 int, existing theories and proof scripts may require a few additional
  1076 type constraints;
  1077 
  1078 * integer division and remainder can now be performed on constant
  1079 arguments;
  1080 
  1081 * many properties of integer multiplication, division and remainder
  1082 are now available;
  1083 
  1084 * An interface to the Stanford Validity Checker (SVC) is available through the
  1085 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1086 are proved automatically.  SVC must be installed separately, and its results
  1087 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1088 invocation of the underlying oracle).  For SVC see
  1089   http://verify.stanford.edu/SVC
  1090 
  1091 * IsaMakefile: the HOL-Real target now builds an actual image;
  1092 
  1093 
  1094 ** HOL misc **
  1095 
  1096 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1097 (in Isabelle/Isar) -- by Gertrud Bauer;
  1098 
  1099 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1100 analysis for assembly languages with subtypes;
  1101 
  1102 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1103 -- avoids syntactic ambiguities and treats state, transition, and
  1104 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1105 changed syntax and (many) tactics;
  1106 
  1107 * HOL/inductive: Now also handles more general introduction rules such
  1108   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1109   theorems are now maintained within the theory (maintained via the
  1110   "mono" attribute);
  1111 
  1112 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1113   (using function types) such as
  1114 
  1115   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1116 
  1117 * HOL/record: record_simproc (part of the default simpset) takes care
  1118 of selectors applied to updated records; record_split_tac is no longer
  1119 part of the default claset; update_defs may now be removed from the
  1120 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1121 
  1122   claset_ref () := claset() addSWrapper record_split_wrapper;
  1123   Delsimprocs [record_simproc]
  1124 
  1125 * HOL/typedef: fixed type inference for representing set; type
  1126 arguments now have to occur explicitly on the rhs as type constraints;
  1127 
  1128 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1129 names rather than an ML expression;
  1130 
  1131 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1132 supplied later.  Program schemes can be defined, such as
  1133     "While B C s = (if B s then While B C (C s) else s)"
  1134 where the well-founded relation can be chosen after B and C have been given.
  1135 
  1136 * HOL/List: the constructors of type list are now Nil and Cons;
  1137 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1138 course, ML tools referring to List.list.op # etc. have to be adapted;
  1139 
  1140 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1141 disabled by default; run isabelle with option -m HOL to get back to
  1142 the original Gordon/HOL-style output;
  1143 
  1144 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1145 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1146 
  1147 * HOL basic syntax simplified (more orthogonal): all variants of
  1148 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1149 Eps operator is provided as well: "SOME x. P[x]";
  1150 
  1151 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1152 
  1153 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1154 thus available for user theories;
  1155 
  1156 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1157 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1158 time;
  1159 
  1160 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1161 several times and then mp;
  1162 
  1163 
  1164 *** LK ***
  1165 
  1166 * the notation <<...>> is now available as a notation for sequences of
  1167 formulas;
  1168 
  1169 * the simplifier is now installed
  1170 
  1171 * the axiom system has been generalized (thanks to Soren Heilmann)
  1172 
  1173 * the classical reasoner now has a default rule database
  1174 
  1175 
  1176 *** ZF ***
  1177 
  1178 * new primrec section allows primitive recursive functions to be given
  1179 directly (as in HOL) over datatypes and the natural numbers;
  1180 
  1181 * new tactics induct_tac and exhaust_tac for induction (or case
  1182 analysis) over datatypes and the natural numbers;
  1183 
  1184 * the datatype declaration of type T now defines the recursor T_rec;
  1185 
  1186 * simplification automatically does freeness reasoning for datatype
  1187 constructors;
  1188 
  1189 * automatic type-inference, with AddTCs command to insert new
  1190 type-checking rules;
  1191 
  1192 * datatype introduction rules are now added as Safe Introduction rules
  1193 to the claset;
  1194 
  1195 * the syntax "if P then x else y" is now available in addition to
  1196 if(P,x,y);
  1197 
  1198 
  1199 *** Internal programming interfaces ***
  1200 
  1201 * tuned simplifier trace output; new flag debug_simp;
  1202 
  1203 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1204 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1205 
  1206 * AxClass.axclass_tac lost the theory argument;
  1207 
  1208 * tuned current_goals_markers semantics: begin / end goal avoids
  1209 printing empty lines;
  1210 
  1211 * removed prs and prs_fn hook, which was broken because it did not
  1212 include \n in its semantics, forcing writeln to add one
  1213 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1214 string -> unit if you really want to output text without newline;
  1215 
  1216 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1217 plain output, interface builders may have to enable 'isabelle_font'
  1218 mode to get Isabelle font glyphs as before;
  1219 
  1220 * refined token_translation interface; INCOMPATIBILITY: output length
  1221 now of type real instead of int;
  1222 
  1223 * theory loader actions may be traced via new ThyInfo.add_hook
  1224 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1225 your own database of information attached to *whole* theories -- as
  1226 opposed to intra-theory data slots offered via TheoryDataFun;
  1227 
  1228 * proper handling of dangling sort hypotheses (at last!);
  1229 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1230 extra sort hypotheses that can be witnessed from the type signature;
  1231 the force_strip_shyps flag is gone, any remaining shyps are simply
  1232 left in the theorem (with a warning issued by strip_shyps_warning);
  1233 
  1234 
  1235 
  1236 New in Isabelle98-1 (October 1998)
  1237 ----------------------------------
  1238 
  1239 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1240 
  1241 * several changes of automated proof tools;
  1242 
  1243 * HOL: major changes to the inductive and datatype packages, including
  1244 some minor incompatibilities of theory syntax;
  1245 
  1246 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1247 called `inj_on';
  1248 
  1249 * HOL: removed duplicate thms in Arith:
  1250   less_imp_add_less  should be replaced by  trans_less_add1
  1251   le_imp_add_le      should be replaced by  trans_le_add1
  1252 
  1253 * HOL: unary minus is now overloaded (new type constraints may be
  1254 required);
  1255 
  1256 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1257 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1258 now taken as an integer constant.
  1259 
  1260 * Pure: ML function 'theory_of' renamed to 'theory';
  1261 
  1262 
  1263 *** Proof tools ***
  1264 
  1265 * Simplifier:
  1266   1. Asm_full_simp_tac is now more aggressive.
  1267      1. It will sometimes reorient premises if that increases their power to
  1268         simplify.
  1269      2. It does no longer proceed strictly from left to right but may also
  1270         rotate premises to achieve further simplification.
  1271      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1272      old Asm_full_simp_tac in that it does not rotate premises.
  1273   2. The simplifier now knows a little bit about nat-arithmetic.
  1274 
  1275 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1276 allows for selected deletion of wrappers, by introduction of names for
  1277 wrapper functionals.  This implies that addbefore, addSbefore,
  1278 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1279 and that adding two tactics with the same name overwrites the first
  1280 one (emitting a warning).
  1281   type wrapper = (int -> tactic) -> (int -> tactic)
  1282   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1283   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1284   delWrapper, delSWrapper: claset *  string            -> claset
  1285   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1286 
  1287 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1288 semantics; addbefore now affects only the unsafe part of step_tac
  1289 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1290 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1291 by Force_tac;
  1292 
  1293 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1294 compWrapper; added safe wrapper (and access functions for it);
  1295 
  1296 * HOL/split_all_tac is now much faster and fails if there is nothing
  1297 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1298 and the names of the automatically generated variables have changed.
  1299 split_all_tac has moved within claset() from unsafe wrappers to safe
  1300 wrappers, which means that !!-bound variables are split much more
  1301 aggressively, and safe_tac and clarify_tac now split such variables.
  1302 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1303 Note: the same holds for record_split_tac, which does the job of
  1304 split_all_tac for record fields.
  1305 
  1306 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1307 permanently to the default simpset using Addsplits just like
  1308 Addsimps. They can be removed via Delsplits just like
  1309 Delsimps. Lower-case versions are also available.
  1310 
  1311 * HOL/Simplifier: The rule split_if is now part of the default
  1312 simpset. This means that the simplifier will eliminate all occurrences
  1313 of if-then-else in the conclusion of a goal. To prevent this, you can
  1314 either remove split_if completely from the default simpset by
  1315 `Delsplits [split_if]' or remove it in a specific call of the
  1316 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1317 other case splitting rules to/from the default simpset: every datatype
  1318 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1319 t is the name of the datatype).
  1320 
  1321 * Classical reasoner / Simplifier combination: new force_tac (and
  1322 derivatives Force_tac, force) combines rewriting and classical
  1323 reasoning (and whatever other tools) similarly to auto_tac, but is
  1324 aimed to solve the given subgoal completely.
  1325 
  1326 
  1327 *** General ***
  1328 
  1329 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1330 and `goalw': the theory is no longer needed as an explicit argument -
  1331 the current theory context is used; assumptions are no longer returned
  1332 at the ML-level unless one of them starts with ==> or !!; it is
  1333 recommended to convert to these new commands using isatool fixgoal
  1334 (backup your sources first!);
  1335 
  1336 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1337 the current theory context, and 'theory' to lookup stored theories;
  1338 
  1339 * new theory section 'locale' for declaring constants, assumptions and
  1340 definitions that have local scope;
  1341 
  1342 * new theory section 'nonterminals' for purely syntactic types;
  1343 
  1344 * new theory section 'setup' for generic ML setup functions
  1345 (e.g. package initialization);
  1346 
  1347 * the distribution now includes Isabelle icons: see
  1348 lib/logo/isabelle-{small,tiny}.xpm;
  1349 
  1350 * isatool install - install binaries with absolute references to
  1351 ISABELLE_HOME/bin;
  1352 
  1353 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1354 
  1355 * print mode 'emacs' reserved for Isamode;
  1356 
  1357 * support multiple print (ast) translations per constant name;
  1358 
  1359 * theorems involving oracles are now printed with a suffixed [!];
  1360 
  1361 
  1362 *** HOL ***
  1363 
  1364 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1365 
  1366 * HOL/inductive package reorganized and improved: now supports mutual
  1367 definitions such as
  1368 
  1369   inductive EVEN ODD
  1370     intrs
  1371       null "0 : EVEN"
  1372       oddI "n : EVEN ==> Suc n : ODD"
  1373       evenI "n : ODD ==> Suc n : EVEN"
  1374 
  1375 new theorem list "elims" contains an elimination rule for each of the
  1376 recursive sets; inductive definitions now handle disjunctive premises
  1377 correctly (also ZF);
  1378 
  1379 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1380 "mutual_induct" no longer exists - the induction rule is always
  1381 contained in "induct";
  1382 
  1383 
  1384 * HOL/datatype package re-implemented and greatly improved: now
  1385 supports mutually recursive datatypes such as
  1386 
  1387   datatype
  1388     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1389             | SUM ('a aexp) ('a aexp)
  1390             | DIFF ('a aexp) ('a aexp)
  1391             | NUM 'a
  1392   and
  1393     'a bexp = LESS ('a aexp) ('a aexp)
  1394             | AND ('a bexp) ('a bexp)
  1395             | OR ('a bexp) ('a bexp)
  1396 
  1397 as well as indirectly recursive datatypes such as
  1398 
  1399   datatype
  1400     ('a, 'b) term = Var 'a
  1401                   | App 'b ((('a, 'b) term) list)
  1402 
  1403 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1404 induction on mutually / indirectly recursive datatypes.
  1405 
  1406 Primrec equations are now stored in theory and can be accessed via
  1407 <function_name>.simps.
  1408 
  1409 INCOMPATIBILITIES:
  1410 
  1411   - Theories using datatypes must now have theory Datatype as an
  1412     ancestor.
  1413   - The specific <typename>.induct_tac no longer exists - use the
  1414     generic induct_tac instead.
  1415   - natE has been renamed to nat.exhaust - use exhaust_tac
  1416     instead of res_inst_tac ... natE. Note that the variable
  1417     names in nat.exhaust differ from the names in natE, this
  1418     may cause some "fragile" proofs to fail.
  1419   - The theorems split_<typename>_case and split_<typename>_case_asm
  1420     have been renamed to <typename>.split and <typename>.split_asm.
  1421   - Since default sorts of type variables are now handled correctly,
  1422     some datatype definitions may have to be annotated with explicit
  1423     sort constraints.
  1424   - Primrec definitions no longer require function name and type
  1425     of recursive argument.
  1426 
  1427 Consider using isatool fixdatatype to adapt your theories and proof
  1428 scripts to the new package (backup your sources first!).
  1429 
  1430 
  1431 * HOL/record package: considerably improved implementation; now
  1432 includes concrete syntax for record types, terms, updates; theorems
  1433 for surjective pairing and splitting !!-bound record variables; proof
  1434 support is as follows:
  1435 
  1436   1) standard conversions (selectors or updates applied to record
  1437 constructor terms) are part of the standard simpset;
  1438 
  1439   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1440 made part of standard simpset and claset via addIffs;
  1441 
  1442   3) a tactic for record field splitting (record_split_tac) is part of
  1443 the standard claset (addSWrapper);
  1444 
  1445 To get a better idea about these rules you may retrieve them via
  1446 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1447 the name of your record type.
  1448 
  1449 The split tactic 3) conceptually simplifies by the following rule:
  1450 
  1451   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1452 
  1453 Thus any record variable that is bound by meta-all will automatically
  1454 blow up into some record constructor term, consequently the
  1455 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1456 solve record problems automatically.
  1457 
  1458 
  1459 * reorganized the main HOL image: HOL/Integ and String loaded by
  1460 default; theory Main includes everything;
  1461 
  1462 * automatic simplification of integer sums and comparisons, using cancellation;
  1463 
  1464 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1465 
  1466 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1467 
  1468 * many new identities for unions, intersections, set difference, etc.;
  1469 
  1470 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1471 called split_if, split_split, split_sum_case and split_nat_case (to go
  1472 with add/delsplits);
  1473 
  1474 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1475 (?x::unit) = (); this is made part of the default simpset, which COULD
  1476 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1477 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1478 unit_abs_eta_conv is added in order to counter the effect of
  1479 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1480 %u.f();
  1481 
  1482 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1483 makes more sense);
  1484 
  1485 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1486   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1487   disjointness reasoning but breaking a few old proofs.
  1488 
  1489 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1490 to 'converse' from 'inverse' (for compatibility with ZF and some
  1491 literature);
  1492 
  1493 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1494 the well-founded relation;
  1495 
  1496 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1497     Compl A.  The "Compl" syntax remains available as input syntax for this
  1498     release ONLY.
  1499 
  1500 * HOL/Update: new theory of function updates:
  1501     f(a:=b) == %x. if x=a then b else f x
  1502 may also be iterated as in f(a:=b,c:=d,...);
  1503 
  1504 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1505 
  1506 * HOL/List:
  1507   - new function list_update written xs[i:=v] that updates the i-th
  1508     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1509   - new function `upt' written [i..j(] which generates the list
  1510     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1511     bound write [i..j], which is a shorthand for [i..j+1(].
  1512   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1513 
  1514 * HOL/Arith:
  1515   - removed 'pred' (predecessor) function;
  1516   - generalized some theorems about n-1;
  1517   - many new laws about "div" and "mod";
  1518   - new laws about greatest common divisors (see theory ex/Primes);
  1519 
  1520 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1521 instead of "inverse";
  1522 
  1523 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1524   of the multiset ordering;
  1525 
  1526 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1527   (not included by default);
  1528 
  1529 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1530 
  1531 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1532   programs, i.e. different program variables may have different types.
  1533 
  1534 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1535   [previously, this check worked only if the rewrite rule was unconditional]
  1536   Now rew can involve either definitions or equalities (either == or =).
  1537 
  1538 
  1539 *** ZF ***
  1540 
  1541 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1542   only the theorems proved on ZF.ML;
  1543 
  1544 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1545   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1546   disjointness reasoning but breaking a few old proofs.
  1547 
  1548 * ZF/Update: new theory of function updates
  1549     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1550   may also be iterated as in f(a:=b,c:=d,...);
  1551 
  1552 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1553 
  1554 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1555   [previously, this check worked only if the rewrite rule was unconditional]
  1556   Now rew can involve either definitions or equalities (either == or =).
  1557 
  1558 * case_tac provided for compatibility with HOL
  1559     (like the old excluded_middle_tac, but with subgoals swapped)
  1560 
  1561 
  1562 *** Internal programming interfaces ***
  1563 
  1564 * Pure: several new basic modules made available for general use, see
  1565 also src/Pure/README;
  1566 
  1567 * improved the theory data mechanism to support encapsulation (data
  1568 kind name replaced by private Object.kind, acting as authorization
  1569 key); new type-safe user interface via functor TheoryDataFun; generic
  1570 print_data function becomes basically useless;
  1571 
  1572 * removed global_names compatibility flag -- all theory declarations
  1573 are qualified by default;
  1574 
  1575 * module Pure/Syntax now offers quote / antiquote translation
  1576 functions (useful for Hoare logic etc. with implicit dependencies);
  1577 see HOL/ex/Antiquote for an example use;
  1578 
  1579 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1580 cterm -> thm;
  1581 
  1582 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1583 subgoal;
  1584 
  1585 * Display.print_goals function moved to Locale.print_goals;
  1586 
  1587 * standard print function for goals supports current_goals_markers
  1588 variable for marking begin of proof, end of proof, start of goal; the
  1589 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1590 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1591 for example;
  1592 
  1593 
  1594 
  1595 New in Isabelle98 (January 1998)
  1596 --------------------------------
  1597 
  1598 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1599 
  1600 * changed lexical syntax of terms / types: dots made part of long
  1601 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1602 
  1603 * simpset (and claset) reference variable replaced by functions
  1604 simpset / simpset_ref;
  1605 
  1606 * no longer supports theory aliases (via merge) and non-trivial
  1607 implicit merge of thms' signatures;
  1608 
  1609 * most internal names of constants changed due to qualified names;
  1610 
  1611 * changed Pure/Sequence interface (see Pure/seq.ML);
  1612 
  1613 
  1614 *** General Changes ***
  1615 
  1616 * hierachically structured name spaces (for consts, types, axms, thms
  1617 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1618 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1619 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1620 long_names for fully qualified output names; NOTE: ML programs
  1621 (special tactics, packages etc.) referring to internal names may have
  1622 to be adapted to cope with fully qualified names; in case of severe
  1623 backward campatibility problems try setting 'global_names' at compile
  1624 time to have enrything declared within a flat name space; one may also
  1625 fine tune name declarations in theories via the 'global' and 'local'
  1626 section;
  1627 
  1628 * reimplemented the implicit simpset and claset using the new anytype
  1629 data filed in signatures; references simpset:simpset ref etc. are
  1630 replaced by functions simpset:unit->simpset and
  1631 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1632 to patch your ML files accordingly;
  1633 
  1634 * HTML output now includes theory graph data for display with Java
  1635 applet or isatool browser; data generated automatically via isatool
  1636 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1637 
  1638 * defs may now be conditional; improved rewrite_goals_tac to handle
  1639 conditional equations;
  1640 
  1641 * defs now admits additional type arguments, using TYPE('a) syntax;
  1642 
  1643 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1644 creates a new theory node; implicit merge of thms' signatures is
  1645 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1646 transfer:theory->thm->thm in (rare) cases;
  1647 
  1648 * improved handling of draft signatures / theories; draft thms (and
  1649 ctyps, cterms) are automatically promoted to real ones;
  1650 
  1651 * slightly changed interfaces for oracles: admit many per theory, named
  1652 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1653 
  1654 * print_goals: optional output of const types (set show_consts and
  1655 show_types);
  1656 
  1657 * improved output of warnings (###) and errors (***);
  1658 
  1659 * subgoal_tac displays a warning if the new subgoal has type variables;
  1660 
  1661 * removed old README and Makefiles;
  1662 
  1663 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1664 
  1665 * removed obsolete init_pps and init_database;
  1666 
  1667 * deleted the obsolete tactical STATE, which was declared by
  1668     fun STATE tacfun st = tacfun st st;
  1669 
  1670 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1671 (which abbreviates $HOME);
  1672 
  1673 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1674 use isatool fixseq to adapt your ML programs (this works for fully
  1675 qualified references to the Sequence structure only!);
  1676 
  1677 * use_thy no longer requires writable current directory; it always
  1678 reloads .ML *and* .thy file, if either one is out of date;
  1679 
  1680 
  1681 *** Classical Reasoner ***
  1682 
  1683 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1684 tactics that use classical reasoning to simplify a subgoal without
  1685 splitting it into several subgoals;
  1686 
  1687 * Safe_tac: like safe_tac but uses the default claset;
  1688 
  1689 
  1690 *** Simplifier ***
  1691 
  1692 * added simplification meta rules:
  1693     (asm_)(full_)simplify: simpset -> thm -> thm;
  1694 
  1695 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1696 logics (again);
  1697 
  1698 * added prems argument to simplification procedures;
  1699 
  1700 * HOL, FOL, ZF: added infix function `addsplits':
  1701   instead of `<simpset> setloop (split_tac <thms>)'
  1702   you can simply write `<simpset> addsplits <thms>'
  1703 
  1704 
  1705 *** Syntax ***
  1706 
  1707 * TYPE('a) syntax for type reflection terms;
  1708 
  1709 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1710 
  1711 * pretty printer: changed order of mixfix annotation preference (again!);
  1712 
  1713 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1714 
  1715 
  1716 *** HOL ***
  1717 
  1718 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1719   with `addloop' of the simplifier to faciliate case splitting in premises.
  1720 
  1721 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1722 
  1723 * HOL/Auth: new protocol proofs including some for the Internet
  1724   protocol TLS;
  1725 
  1726 * HOL/Map: new theory of `maps' a la VDM;
  1727 
  1728 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1729 cancelling out common nat summands from =, <, <= (in)equalities, or
  1730 differences; simplification procedures nat_cancel_factor for
  1731 cancelling common factor from =, <, <= (in)equalities over natural
  1732 sums; nat_cancel contains both kinds of procedures, it is installed by
  1733 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1734 
  1735 * HOL/simplifier: terms of the form
  1736   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1737   are rewritten to
  1738   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1739   and those of the form
  1740   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1741   are rewritten to
  1742   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1743 
  1744 * HOL/datatype
  1745   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1746 
  1747   P(t_case f1 ... fn x) =
  1748      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1749         ...
  1750        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1751      )
  1752 
  1753   and a theorem `split_t_case_asm' of the form
  1754 
  1755   P(t_case f1 ... fn x) =
  1756     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1757         ...
  1758        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1759      )
  1760   which can be added to a simpset via `addsplits'. The existing theorems
  1761   expand_list_case and expand_option_case have been renamed to
  1762   split_list_case and split_option_case.
  1763 
  1764 * HOL/Arithmetic:
  1765   - `pred n' is automatically converted to `n-1'.
  1766     Users are strongly encouraged not to use `pred' any longer,
  1767     because it will disappear altogether at some point.
  1768   - Users are strongly encouraged to write "0 < n" rather than
  1769     "n ~= 0". Theorems and proof tools have been modified towards this
  1770     `standard'.
  1771 
  1772 * HOL/Lists:
  1773   the function "set_of_list" has been renamed "set" (and its theorems too);
  1774   the function "nth" now takes its arguments in the reverse order and
  1775   has acquired the infix notation "!" as in "xs!n".
  1776 
  1777 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1778 
  1779 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1780   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1781 
  1782 * HOL/record: extensible records with schematic structural subtyping
  1783 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1784 still lacks various theorems and concrete record syntax;
  1785 
  1786 
  1787 *** HOLCF ***
  1788 
  1789 * removed "axioms" and "generated by" sections;
  1790 
  1791 * replaced "ops" section by extended "consts" section, which is capable of
  1792   handling the continuous function space "->" directly;
  1793 
  1794 * domain package:
  1795   . proves theorems immediately and stores them in the theory,
  1796   . creates hierachical name space,
  1797   . now uses normal mixfix annotations (instead of cinfix...),
  1798   . minor changes to some names and values (for consistency),
  1799   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1800   . separator between mutual domain defs: changed "," to "and",
  1801   . improved handling of sort constraints;  now they have to
  1802     appear on the left-hand side of the equations only;
  1803 
  1804 * fixed LAM <x,y,zs>.b syntax;
  1805 
  1806 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1807 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1808 
  1809 
  1810 *** FOL and ZF ***
  1811 
  1812 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1813   with `addloop' of the simplifier to faciliate case splitting in premises.
  1814 
  1815 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1816 in HOL, they strip ALL and --> from proved theorems;
  1817 
  1818 
  1819 
  1820 New in Isabelle94-8 (May 1997)
  1821 ------------------------------
  1822 
  1823 *** General Changes ***
  1824 
  1825 * new utilities to build / run / maintain Isabelle etc. (in parts
  1826 still somewhat experimental); old Makefiles etc. still functional;
  1827 
  1828 * new 'Isabelle System Manual';
  1829 
  1830 * INSTALL text, together with ./configure and ./build scripts;
  1831 
  1832 * reimplemented type inference for greater efficiency, better error
  1833 messages and clean internal interface;
  1834 
  1835 * prlim command for dealing with lots of subgoals (an easier way of
  1836 setting goals_limit);
  1837 
  1838 
  1839 *** Syntax ***
  1840 
  1841 * supports alternative (named) syntax tables (parser and pretty
  1842 printer); internal interface is provided by add_modesyntax(_i);
  1843 
  1844 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1845 be used in conjunction with the Isabelle symbol font; uses the
  1846 "symbols" syntax table;
  1847 
  1848 * added token_translation interface (may translate name tokens in
  1849 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1850 the current print_mode); IMPORTANT: user print translation functions
  1851 are responsible for marking newly introduced bounds
  1852 (Syntax.mark_boundT);
  1853 
  1854 * token translations for modes "xterm" and "xterm_color" that display
  1855 names in bold, underline etc. or colors (which requires a color
  1856 version of xterm);
  1857 
  1858 * infixes may now be declared with names independent of their syntax;
  1859 
  1860 * added typed_print_translation (like print_translation, but may
  1861 access type of constant);
  1862 
  1863 
  1864 *** Classical Reasoner ***
  1865 
  1866 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1867 some limitations.  Blast_tac...
  1868   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1869   + ignores elimination rules that don't have the correct format
  1870         (the conclusion MUST be a formula variable)
  1871   + ignores types, which can make HOL proofs fail
  1872   + rules must not require higher-order unification, e.g. apply_type in ZF
  1873     [message "Function Var's argument not a bound variable" relates to this]
  1874   + its proof strategy is more general but can actually be slower
  1875 
  1876 * substitution with equality assumptions no longer permutes other
  1877 assumptions;
  1878 
  1879 * minor changes in semantics of addafter (now called addaltern); renamed
  1880 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1881 (and access functions for it);
  1882 
  1883 * improved combination of classical reasoner and simplifier:
  1884   + functions for handling clasimpsets
  1885   + improvement of addss: now the simplifier is called _after_ the
  1886     safe steps.
  1887   + safe variant of addss called addSss: uses safe simplifications
  1888     _during_ the safe steps. It is more complete as it allows multiple
  1889     instantiations of unknowns (e.g. with slow_tac).
  1890 
  1891 *** Simplifier ***
  1892 
  1893 * added interface for simplification procedures (functions that
  1894 produce *proven* rewrite rules on the fly, depending on current
  1895 redex);
  1896 
  1897 * ordering on terms as parameter (used for ordered rewriting);
  1898 
  1899 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1900 
  1901 * the solver is now split into a safe and an unsafe part.
  1902 This should be invisible for the normal user, except that the
  1903 functions setsolver and addsolver have been renamed to setSolver and
  1904 addSolver; added safe_asm_full_simp_tac;
  1905 
  1906 
  1907 *** HOL ***
  1908 
  1909 * a generic induction tactic `induct_tac' which works for all datatypes and
  1910 also for type `nat';
  1911 
  1912 * a generic case distinction tactic `exhaust_tac' which works for all
  1913 datatypes and also for type `nat';
  1914 
  1915 * each datatype comes with a function `size';
  1916 
  1917 * patterns in case expressions allow tuple patterns as arguments to
  1918 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1919 
  1920 * primrec now also works with type nat;
  1921 
  1922 * recdef: a new declaration form, allows general recursive functions to be
  1923 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1924 
  1925 * the constant for negation has been renamed from "not" to "Not" to
  1926 harmonize with FOL, ZF, LK, etc.;
  1927 
  1928 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1929 infinite lists;
  1930 
  1931 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1932 
  1933 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1934 problems in commutative rings, using axiomatic type classes for + and *;
  1935 
  1936 * more examples in HOL/MiniML and HOL/Auth;
  1937 
  1938 * more default rewrite rules for quantifiers, union/intersection;
  1939 
  1940 * a new constant `arbitrary == @x.False';
  1941 
  1942 * HOLCF/IOA replaces old HOL/IOA;
  1943 
  1944 * HOLCF changes: derived all rules and arities
  1945   + axiomatic type classes instead of classes
  1946   + typedef instead of faking type definitions
  1947   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1948   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1949   + eliminated the types void, one, tr
  1950   + use unit lift and bool lift (with translations) instead of one and tr
  1951   + eliminated blift from Lift3.thy (use Def instead of blift)
  1952   all eliminated rules are derived as theorems --> no visible changes ;
  1953 
  1954 
  1955 *** ZF ***
  1956 
  1957 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1958 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1959 as ZF_cs addSIs [equalityI];
  1960 
  1961 
  1962 
  1963 New in Isabelle94-7 (November 96)
  1964 ---------------------------------
  1965 
  1966 * allowing negative levels (as offsets) in prlev and choplev;
  1967 
  1968 * super-linear speedup for large simplifications;
  1969 
  1970 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1971 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1972 FAIL); can suppress it using the command Delsimps (ex_simps @
  1973 all_simps); De Morgan laws are also now included, by default;
  1974 
  1975 * improved printing of ==>  :  ~:
  1976 
  1977 * new object-logic "Sequents" adds linear logic, while replacing LK
  1978 and Modal (thanks to Sara Kalvala);
  1979 
  1980 * HOL/Auth: correctness proofs for authentication protocols;
  1981 
  1982 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1983 examples on HOL/Auth);
  1984 
  1985 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1986 the rewriter and classical reasoner simultaneously;
  1987 
  1988 * function uresult no longer returns theorems in "standard" format;
  1989 regain previous version by: val uresult = standard o uresult;
  1990 
  1991 
  1992 
  1993 New in Isabelle94-6
  1994 -------------------
  1995 
  1996 * oracles -- these establish an interface between Isabelle and trusted
  1997 external reasoners, which may deliver results as theorems;
  1998 
  1999 * proof objects (in particular record all uses of oracles);
  2000 
  2001 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2002 
  2003 * "constdefs" section in theory files;
  2004 
  2005 * "primrec" section (HOL) no longer requires names;
  2006 
  2007 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2008 
  2009 
  2010 
  2011 New in Isabelle94-5
  2012 -------------------
  2013 
  2014 * reduced space requirements;
  2015 
  2016 * automatic HTML generation from theories;
  2017 
  2018 * theory files no longer require "..." (quotes) around most types;
  2019 
  2020 * new examples, including two proofs of the Church-Rosser theorem;
  2021 
  2022 * non-curried (1994) version of HOL is no longer distributed;
  2023 
  2024 
  2025 
  2026 New in Isabelle94-4
  2027 -------------------
  2028 
  2029 * greatly reduced space requirements;
  2030 
  2031 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2032 
  2033 * searchable theorem database (see the section "Retrieving theorems" on
  2034 page 8 of the Reference Manual);
  2035 
  2036 * new examples, including Grabczewski's monumental case study of the
  2037 Axiom of Choice;
  2038 
  2039 * The previous version of HOL renamed to Old_HOL;
  2040 
  2041 * The new version of HOL (previously called CHOL) uses a curried syntax
  2042 for functions.  Application looks like f a b instead of f(a,b);
  2043 
  2044 * Mutually recursive inductive definitions finally work in HOL;
  2045 
  2046 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2047 translates to the operator "split";
  2048 
  2049 
  2050 
  2051 New in Isabelle94-3
  2052 -------------------
  2053 
  2054 * new infix operator, addss, allowing the classical reasoner to
  2055 perform simplification at each step of its search.  Example:
  2056         fast_tac (cs addss ss)
  2057 
  2058 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2059 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2060 look like (a,b) instead of <a,b>;
  2061 
  2062 * PLEASE NOTE: CHOL will eventually replace HOL!
  2063 
  2064 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2065 It translates to the operator "split".  A new theory of integers is available;
  2066 
  2067 * In ZF, integer numerals now denote two's-complement binary integers.
  2068 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2069 
  2070 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2071 of the Axiom of Choice;
  2072 
  2073 
  2074 
  2075 New in Isabelle94-2
  2076 -------------------
  2077 
  2078 * Significantly faster resolution;
  2079 
  2080 * the different sections in a .thy file can now be mixed and repeated
  2081 freely;
  2082 
  2083 * Database of theorems for FOL, HOL and ZF.  New
  2084 commands including qed, qed_goal and bind_thm store theorems in the database.
  2085 
  2086 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2087 a given theory (thms_of), or find out what theory a theorem was proved in
  2088 (theory_of_thm);
  2089 
  2090 * Bugs fixed in the inductive definition and datatype packages;
  2091 
  2092 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2093 and HOL_dup_cs obsolete;
  2094 
  2095 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2096 have been removed;
  2097 
  2098 * Simpler definition of function space in ZF;
  2099 
  2100 * new results about cardinal and ordinal arithmetic in ZF;
  2101 
  2102 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2103 types;
  2104 
  2105 
  2106 $Id$