NEWS
author wenzelm
Tue Dec 11 16:22:09 2001 +0100 (2001-12-11)
changeset 12467 b5630a4ea5d8
parent 12457 cbfc53e45476
child 12472 3307149f1ec2
permissions -rw-r--r--
isatools "symbolinput" and "nonascii" have disappeared;
     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; the related isatools
   303 "symbolinput" and "nonascii" have disappeared as well;
   304 
   305 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   306 
   307 * system: Proof General keywords specification is now part of the
   308 Isabelle distribution (see etc/isar-keywords.el);
   309 
   310 * system: smart selection of Isabelle process versus Isabelle
   311 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   312 run both "isabelle" and "Isabelle" even if file names are badly
   313 damaged (executable inspects the case of the first letter of its own
   314 name); added separate "isabelle-process" and "isabelle-interface";
   315 
   316 
   317 
   318 New in Isabelle99-2 (February 2001)
   319 -----------------------------------
   320 
   321 *** Overview of INCOMPATIBILITIES ***
   322 
   323 * HOL: please note that theories in the Library and elsewhere often use the
   324 new-style (Isar) format; to refer to their theorems in an ML script you must
   325 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   326 
   327 * HOL: inductive package no longer splits induction rule aggressively,
   328 but only as far as specified by the introductions given; the old
   329 format may be recovered via ML function complete_split_rule or attribute
   330 'split_rule (complete)';
   331 
   332 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   333 gfp_Tarski to gfp_unfold;
   334 
   335 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   336 
   337 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   338 relation); infix "^^" has been renamed "``"; infix "``" has been
   339 renamed "`"; "univalent" has been renamed "single_valued";
   340 
   341 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   342 operation;
   343 
   344 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   345 
   346 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   347 
   348 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   349 consequence, it is no longer monotonic wrt. the local goal context
   350 (which is now passed through the inductive cases);
   351 
   352 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   353 \<gg> to \<ggreater>;
   354 
   355 
   356 *** Document preparation ***
   357 
   358 * \isabellestyle{NAME} selects version of Isabelle output (currently
   359 available: are "it" for near math-mode best-style output, "sl" for
   360 slanted text style, and "tt" for plain type-writer; if no
   361 \isabellestyle command is given, output is according to slanted
   362 type-writer);
   363 
   364 * support sub/super scripts (for single symbols only), input syntax is
   365 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   366 
   367 * some more standard symbols; see Appendix A of the system manual for
   368 the complete list of symbols defined in isabellesym.sty;
   369 
   370 * improved isabelle style files; more abstract symbol implementation
   371 (should now use \isamath{...} and \isatext{...} in custom symbol
   372 definitions);
   373 
   374 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   375 state; Note that presentation of goal states does not conform to
   376 actual human-readable proof documents.  Please do not include goal
   377 states into document output unless you really know what you are doing!
   378 
   379 * proper indentation of antiquoted output with proportional LaTeX
   380 fonts;
   381 
   382 * no_document ML operator temporarily disables LaTeX document
   383 generation;
   384 
   385 * isatool unsymbolize tunes sources for plain ASCII communication;
   386 
   387 
   388 *** Isar ***
   389 
   390 * Pure: Isar now suffers initial goal statements to contain unbound
   391 schematic variables (this does not conform to actual readable proof
   392 documents, due to unpredictable outcome and non-compositional proof
   393 checking); users who know what they are doing may use schematic goals
   394 for Prolog-style synthesis of proven results;
   395 
   396 * Pure: assumption method (an implicit finishing) now handles actual
   397 rules as well;
   398 
   399 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   400 initial goal, declare "that" only as Pure intro (only for single
   401 steps); the "that" rule assumption may now be involved in implicit
   402 finishing, thus ".." becomes a feasible for trivial obtains;
   403 
   404 * Pure: default proof step now includes 'intro_classes'; thus trivial
   405 instance proofs may be performed by "..";
   406 
   407 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   408 statements as well;
   409 
   410 * Pure: more robust selection of calculational rules;
   411 
   412 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   413 rule (as well as the assumption rule);
   414 
   415 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   416 lemmas, using the graph browser tool;
   417 
   418 * Pure: predict failure of "show" in interactive mode;
   419 
   420 * Pure: 'thms_containing' now takes actual terms as arguments;
   421 
   422 * HOL: improved method 'induct' --- now handles non-atomic goals
   423 (potential INCOMPATIBILITY); tuned error handling;
   424 
   425 * HOL: cases and induct rules now provide explicit hints about the
   426 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   427 any remaining facts are inserted into the goal verbatim;
   428 
   429 * HOL: local contexts (aka cases) may now contain term bindings as
   430 well; the 'cases' and 'induct' methods new provide a ?case binding for
   431 the result to be shown in each case;
   432 
   433 * HOL: added 'recdef_tc' command;
   434 
   435 * isatool convert assists in eliminating legacy ML scripts;
   436 
   437 
   438 *** HOL ***
   439 
   440 * HOL/Library: a collection of generic theories to be used together
   441 with main HOL; the theory loader path already includes this directory
   442 by default; the following existing theories have been moved here:
   443 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   444 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   445 
   446 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   447 modelling and verification task performed in Isabelle/HOL +
   448 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   449 
   450 * HOL/Algebra: special summation operator SUM no longer exists, it has
   451 been replaced by setsum; infix 'assoc' now has priority 50 (like
   452 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   453 'domain', this makes the theory consistent with mathematical
   454 literature;
   455 
   456 * HOL basics: added overloaded operations "inverse" and "divide"
   457 (infix "/"), syntax for generic "abs" operation, generic summation
   458 operator \<Sum>;
   459 
   460 * HOL/typedef: simplified package, provide more useful rules (see also
   461 HOL/subset.thy);
   462 
   463 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   464 now expressed as a proper nested rule (old-style tactic scripts may
   465 require atomize_strip_tac to cope with non-atomic premises);
   466 
   467 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   468 to "split_conv" (old name still available for compatibility);
   469 
   470 * HOL: improved concrete syntax for strings (e.g. allows translation
   471 rules with string literals);
   472 
   473 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   474  and Fleuriot's mechanization of analysis, including the transcendental
   475  functions for the reals;
   476 
   477 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   478 
   479 
   480 *** CTT ***
   481 
   482 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   483 "lam" is displayed as TWO lambda-symbols
   484 
   485 * CTT: theory Main now available, containing everything (that is, Bool
   486 and Arith);
   487 
   488 
   489 *** General ***
   490 
   491 * Pure: the Simplifier has been implemented properly as a derived rule
   492 outside of the actual kernel (at last!); the overall performance
   493 penalty in practical applications is about 50%, while reliability of
   494 the Isabelle inference kernel has been greatly improved;
   495 
   496 * print modes "brackets" and "no_brackets" control output of nested =>
   497 (types) and ==> (props); the default behaviour is "brackets";
   498 
   499 * Provers: fast_tac (and friends) now handle actual object-logic rules
   500 as assumptions as well;
   501 
   502 * system: support Poly/ML 4.0;
   503 
   504 * system: isatool install handles KDE version 1 or 2;
   505 
   506 
   507 
   508 New in Isabelle99-1 (October 2000)
   509 ----------------------------------
   510 
   511 *** Overview of INCOMPATIBILITIES ***
   512 
   513 * HOL: simplification of natural numbers is much changed; to partly
   514 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   515 issue the following ML commands:
   516 
   517   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   518   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   519 
   520 * HOL: simplification no longer dives into case-expressions; this is
   521 controlled by "t.weak_case_cong" for each datatype t;
   522 
   523 * HOL: nat_less_induct renamed to less_induct;
   524 
   525 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   526 fixsome to patch .thy and .ML sources automatically;
   527 
   528   select_equality  -> some_equality
   529   select_eq_Ex     -> some_eq_ex
   530   selectI2EX       -> someI2_ex
   531   selectI2         -> someI2
   532   selectI          -> someI
   533   select1_equality -> some1_equality
   534   Eps_sym_eq       -> some_sym_eq_trivial
   535   Eps_eq           -> some_eq_trivial
   536 
   537 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   538 
   539 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   540 instead);
   541 
   542 * HOL: the recursion equations generated by 'recdef' are now called
   543 f.simps instead of f.rules;
   544 
   545 * HOL: qed_spec_mp now also handles bounded ALL as well;
   546 
   547 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   548 sometimes be needed;
   549 
   550 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   551 
   552 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   553 
   554 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   555 product is now "<*>" instead of "Times"; the lexicographic product is
   556 now "<*lex*>" instead of "**";
   557 
   558 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   559 of main HOL, but was unused); better use HOL's datatype package;
   560 
   561 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   562 the old syntax may be recovered as follows:
   563 
   564   syntax (symbols)
   565     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   566       (infixl "\\<oplus>" 100)
   567 
   568 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   569 
   570 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   571 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   572 internally;
   573 
   574 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   575 changed from A/r to A//r;
   576 
   577 * ZF: new treatment of arithmetic (nat & int) may break some old
   578 proofs;
   579 
   580 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   581 rulify -> rule_format, elimify -> elim_format, ...);
   582 
   583 * Isar/Provers: intro/elim/dest attributes changed; renamed
   584 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   585 should have to change intro!! to intro? only); replaced "delrule" by
   586 "rule del";
   587 
   588 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   589 
   590 * Provers: strengthened force_tac by using new first_best_tac;
   591 
   592 * LaTeX document preparation: several changes of isabelle.sty (see
   593 lib/texinputs);
   594 
   595 
   596 *** Document preparation ***
   597 
   598 * formal comments (text blocks etc.) in new-style theories may now
   599 contain antiquotations of thm/prop/term/typ/text to be presented
   600 according to latex print mode; concrete syntax is like this:
   601 @{term[show_types] "f(x) = a + x"};
   602 
   603 * isatool mkdir provides easy setup of Isabelle session directories,
   604 including proper document sources;
   605 
   606 * generated LaTeX sources are now deleted after successful run
   607 (isatool document -c); may retain a copy somewhere else via -D option
   608 of isatool usedir;
   609 
   610 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   611 style files, achieving self-contained LaTeX sources and simplifying
   612 LaTeX debugging;
   613 
   614 * old-style theories now produce (crude) LaTeX output as well;
   615 
   616 * browser info session directories are now self-contained (may be put
   617 on WWW server seperately); improved graphs of nested sessions; removed
   618 graph for 'all sessions';
   619 
   620 * several improvements in isabelle style files; \isabellestyle{it}
   621 produces fake math mode output; \isamarkupheader is now \section by
   622 default; see lib/texinputs/isabelle.sty etc.;
   623 
   624 
   625 *** Isar ***
   626 
   627 * Isar/Pure: local results and corresponding term bindings are now
   628 subject to Hindley-Milner polymorphism (similar to ML); this
   629 accommodates incremental type-inference very nicely;
   630 
   631 * Isar/Pure: new derived language element 'obtain' supports
   632 generalized existence reasoning;
   633 
   634 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   635 support accumulation of results, without applying any rules yet;
   636 useful to collect intermediate results without explicit name
   637 references, and for use with transitivity rules with more than 2
   638 premises;
   639 
   640 * Isar/Pure: scalable support for case-analysis type proofs: new
   641 'case' language element refers to local contexts symbolically, as
   642 produced by certain proof methods; internally, case names are attached
   643 to theorems as "tags";
   644 
   645 * Isar/Pure: theory command 'hide' removes declarations from
   646 class/type/const name spaces;
   647 
   648 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   649 indicate potential overloading;
   650 
   651 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   652 
   653 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   654 "{a,b,c}" instead of {a,b,c};
   655 
   656 * Isar/Pure now provides its own version of intro/elim/dest
   657 attributes; useful for building new logics, but beware of confusion
   658 with the version in Provers/classical;
   659 
   660 * Isar/Pure: the local context of (non-atomic) goals is provided via
   661 case name 'antecedent';
   662 
   663 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   664 to the current context is now done automatically);
   665 
   666 * Isar/Pure: theory command 'method_setup' provides a simple interface
   667 for definining proof methods in ML;
   668 
   669 * Isar/Provers: intro/elim/dest attributes changed; renamed
   670 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   671 most cases, one should have to change intro!! to intro? only);
   672 replaced "delrule" by "rule del";
   673 
   674 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   675 'symmetric' attribute (the latter supercedes [RS sym]);
   676 
   677 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   678 method modifier); 'simp' method: 'only:' modifier removes loopers as
   679 well (including splits);
   680 
   681 * Isar/Provers: Simplifier and Classical methods now support all kind
   682 of modifiers used in the past, including 'cong', 'iff', etc.
   683 
   684 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   685 of Simplifier and Classical reasoner);
   686 
   687 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   688 now support named cases; major packages (inductive, datatype, primrec,
   689 recdef) support case names and properly name parameters;
   690 
   691 * Isar/HOL: new transitivity rules for substitution in inequalities --
   692 monotonicity conditions are extracted to be proven at end of
   693 calculations;
   694 
   695 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   696 method anyway;
   697 
   698 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   699 split_if split_if_asm; datatype package provides theorems foo.splits =
   700 foo.split foo.split_asm for each datatype;
   701 
   702 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   703 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   704 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   705 use "(cases (simplified))" method in proper proof texts);
   706 
   707 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   708 
   709 * Isar: names of theorems etc. may be natural numbers as well;
   710 
   711 * Isar: 'pr' command: optional arguments for goals_limit and
   712 ProofContext.prems_limit; no longer prints theory contexts, but only
   713 proof states;
   714 
   715 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   716 additional print modes to be specified; e.g. "pr(latex)" will print
   717 proof state according to the Isabelle LaTeX style;
   718 
   719 * Isar: improved support for emulating tactic scripts, including proof
   720 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   721 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   722 (for HOL datatypes);
   723 
   724 * Isar: simplified (more robust) goal selection of proof methods: 1st
   725 goal, all goals, or explicit goal specifier (tactic emulation); thus
   726 'proof method scripts' have to be in depth-first order;
   727 
   728 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   729 
   730 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   731 should instead use individual commands for printing items
   732 (print_commands, print_methods etc.);
   733 
   734 * Isar: added 'nothing' --- the empty list of theorems;
   735 
   736 
   737 *** HOL ***
   738 
   739 * HOL/MicroJava: formalization of a fragment of Java, together with a
   740 corresponding virtual machine and a specification of its bytecode
   741 verifier and a lightweight bytecode verifier, including proofs of
   742 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   743 Cornelia Pusch (see also the homepage of project Bali at
   744 http://isabelle.in.tum.de/Bali/);
   745 
   746 * HOL/Algebra: new theory of rings and univariate polynomials, by
   747 Clemens Ballarin;
   748 
   749 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   750 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   751 Rasmussen;
   752 
   753 * HOL/Lattice: fundamental concepts of lattice theory and order
   754 structures, including duals, properties of bounds versus algebraic
   755 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   756 Theorem for complete lattices etc.; may also serve as a demonstration
   757 for abstract algebraic reasoning using axiomatic type classes, and
   758 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   759 
   760 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   761 von Oheimb;
   762 
   763 * HOL/IMPP: extension of IMP with local variables and mutually
   764 recursive procedures, by David von Oheimb;
   765 
   766 * HOL/Lambda: converted into new-style theory and document;
   767 
   768 * HOL/ex/Multiquote: example of multiple nested quotations and
   769 anti-quotations -- basically a generalized version of de-Bruijn
   770 representation; very useful in avoiding lifting of operations;
   771 
   772 * HOL/record: added general record equality rule to simpset; fixed
   773 select-update simplification procedure to handle extended records as
   774 well; admit "r" as field name;
   775 
   776 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   777 other numeric types and also as the identity of groups, rings, etc.;
   778 
   779 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   780 Types nat and int belong to this axclass;
   781 
   782 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   783    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   784    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   785   two terms #m*u and #n*u are replaced by #(m+n)*u
   786     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   787   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   788     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   789 
   790 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   791 powerful prover for predicate logic but knows nothing of clasets; see
   792 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   793 
   794 * HOL: new version of "case_tac" subsumes both boolean case split and
   795 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   796 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   797 
   798 * HOL: simplification no longer dives into case-expressions: only the
   799 selector expression is simplified, but not the remaining arms; to
   800 enable full simplification of case-expressions for datatype t, you may
   801 remove t.weak_case_cong from the simpset, either globally (Delcongs
   802 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   803 
   804 * HOL/recdef: the recursion equations generated by 'recdef' for
   805 function 'f' are now called f.simps instead of f.rules; if all
   806 termination conditions are proved automatically, these simplification
   807 rules are added to the simpset, as in primrec; rules may be named
   808 individually as well, resulting in a separate list of theorems for
   809 each equation;
   810 
   811 * HOL/While is a new theory that provides a while-combinator. It
   812 permits the definition of tail-recursive functions without the
   813 provision of a termination measure. The latter is necessary once the
   814 invariant proof rule for while is applied.
   815 
   816 * HOL: new (overloaded) notation for the set of elements below/above
   817 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   818 
   819 * HOL: theorems impI, allI, ballI bound as "strip";
   820 
   821 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   822 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   823 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   824 
   825 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   826 
   827 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   828 main HOL, but was unused);
   829 
   830 * HOL: fewer consts declared as global (e.g. have to refer to
   831 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   832 
   833 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   834 in case of overlap with user translations (e.g. judgements over
   835 tuples); (note that the underlying logical represenation is still
   836 bogus);
   837 
   838 
   839 *** ZF ***
   840 
   841 * ZF: simplification automatically cancels common terms in arithmetic
   842 expressions over nat and int;
   843 
   844 * ZF: new treatment of nat to minimize type-checking: all operators
   845 coerce their operands to a natural number using the function natify,
   846 making the algebraic laws unconditional;
   847 
   848 * ZF: as above, for int: operators coerce their operands to an integer
   849 using the function intify;
   850 
   851 * ZF: the integer library now contains many of the usual laws for the
   852 orderings, including $<=, and monotonicity laws for $+ and $*;
   853 
   854 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   855 simplification;
   856 
   857 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   858 to the simplifier and classical reasoner simultaneously;
   859 
   860 
   861 *** General ***
   862 
   863 * Provers: blast_tac now handles actual object-logic rules as
   864 assumptions; note that auto_tac uses blast_tac internally as well;
   865 
   866 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   867 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   868 
   869 * Provers: delrules now handles destruct rules as well (no longer need
   870 explicit make_elim);
   871 
   872 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   873   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   874 use instead the strong form,
   875   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   876 in HOL, FOL and ZF the function cla_make_elim will create such rules
   877 from destruct-rules;
   878 
   879 * Provers: Simplifier.easy_setup provides a fast path to basic
   880 Simplifier setup for new object-logics;
   881 
   882 * Pure: AST translation rules no longer require constant head on LHS;
   883 
   884 * Pure: improved name spaces: ambiguous output is qualified; support
   885 for hiding of names;
   886 
   887 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   888 XSYMBOL_HOME; no longer need to do manual configuration in most
   889 situations;
   890 
   891 * system: compression of ML heaps images may now be controlled via -c
   892 option of isabelle and isatool usedir (currently only observed by
   893 Poly/ML);
   894 
   895 * system: isatool installfonts may handle X-Symbol fonts as well (very
   896 useful for remote X11);
   897 
   898 * system: provide TAGS file for Isabelle sources;
   899 
   900 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   901 order;
   902 
   903 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   904 timing flag supersedes proof_timing and Toplevel.trace;
   905 
   906 * ML: new combinators |>> and |>>> for incremental transformations
   907 with secondary results (e.g. certain theory extensions):
   908 
   909 * ML: PureThy.add_defs gets additional argument to indicate potential
   910 overloading (usually false);
   911 
   912 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   913 results;
   914 
   915 
   916 
   917 New in Isabelle99 (October 1999)
   918 --------------------------------
   919 
   920 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   921 
   922 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   923 are no longer simplified.  (This allows the simplifier to unfold recursive
   924 functional programs.)  To restore the old behaviour, declare
   925 
   926     Delcongs [if_weak_cong];
   927 
   928 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   929 complement;
   930 
   931 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   932 
   933 * HOL/datatype: mutual_induct_tac no longer exists --
   934   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   935 
   936 * HOL/typedef: fixed type inference for representing set; type
   937 arguments now have to occur explicitly on the rhs as type constraints;
   938 
   939 * ZF: The con_defs part of an inductive definition may no longer refer
   940 to constants declared in the same theory;
   941 
   942 * HOL, ZF: the function mk_cases, generated by the inductive
   943 definition package, has lost an argument.  To simplify its result, it
   944 uses the default simpset instead of a supplied list of theorems.
   945 
   946 * HOL/List: the constructors of type list are now Nil and Cons;
   947 
   948 * Simplifier: the type of the infix ML functions
   949         setSSolver addSSolver setSolver addSolver
   950 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   951 for packaging solvers. A solver is created via
   952         mk_solver: string -> (thm list -> int -> tactic) -> solver
   953 where the string argument is only a comment.
   954 
   955 
   956 *** Proof tools ***
   957 
   958 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   959 decision procedure for linear arithmetic. Currently it is used for
   960 types `nat', `int', and `real' in HOL (see below); it can, should and
   961 will be instantiated for other types and logics as well.
   962 
   963 * The simplifier now accepts rewrite rules with flexible heads, eg
   964      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   965   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   966   matching.
   967 
   968 
   969 *** General ***
   970 
   971 * New Isabelle/Isar subsystem provides an alternative to traditional
   972 tactical theorem proving; together with the ProofGeneral/isar user
   973 interface it offers an interactive environment for developing human
   974 readable proof documents (Isar == Intelligible semi-automated
   975 reasoning); for further information see isatool doc isar-ref,
   976 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   977 
   978 * improved and simplified presentation of theories: better HTML markup
   979 (including colors), graph views in several sizes; isatool usedir now
   980 provides a proper interface for user theories (via -P option); actual
   981 document preparation based on (PDF)LaTeX is available as well (for
   982 new-style theories only); see isatool doc system for more information;
   983 
   984 * native support for Proof General, both for classic Isabelle and
   985 Isabelle/Isar;
   986 
   987 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   988 using the graph browser tool;
   989 
   990 * Isabelle manuals now also available as PDF;
   991 
   992 * theory loader rewritten from scratch (may not be fully
   993 bug-compatible); old loadpath variable has been replaced by show_path,
   994 add_path, del_path, reset_path functions; new operations such as
   995 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   996 isatool doc ref);
   997 
   998 * improved isatool install: option -k creates KDE application icon,
   999 option -p DIR installs standalone binaries;
  1000 
  1001 * added ML_PLATFORM setting (useful for cross-platform installations);
  1002 more robust handling of platform specific ML images for SML/NJ;
  1003 
  1004 * the settings environment is now statically scoped, i.e. it is never
  1005 created again in sub-processes invoked from isabelle, isatool, or
  1006 Isabelle;
  1007 
  1008 * path element specification '~~' refers to '$ISABELLE_HOME';
  1009 
  1010 * in locales, the "assumes" and "defines" parts may be omitted if
  1011 empty;
  1012 
  1013 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1014 long arrows);
  1015 
  1016 * new print_mode "HTML";
  1017 
  1018 * new flag show_tags controls display of tags of theorems (which are
  1019 basically just comments that may be attached by some tools);
  1020 
  1021 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1022 mode and goal output format:
  1023 
  1024 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1025 244c244
  1026 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1027 ---
  1028 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1029 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1030 181c181
  1031 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1032 ---
  1033 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1034 
  1035 * function bind_thms stores lists of theorems (cf. bind_thm);
  1036 
  1037 * new shorthand tactics ftac, eatac, datac, fatac;
  1038 
  1039 * qed (and friends) now accept "" as result name; in that case the
  1040 theorem is not stored, but proper checks and presentation of the
  1041 result still apply;
  1042 
  1043 * theorem database now also indexes constants "Trueprop", "all",
  1044 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1045 
  1046 
  1047 *** HOL ***
  1048 
  1049 ** HOL arithmetic **
  1050 
  1051 * There are now decision procedures for linear arithmetic over nat and
  1052 int:
  1053 
  1054 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1055 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1056 are treated as atomic; subformulae not involving type `nat' or `int'
  1057 are ignored; quantified subformulae are ignored unless they are
  1058 positive universal or negative existential. The tactic has to be
  1059 invoked by hand and can be a little bit slow. In particular, the
  1060 running time is exponential in the number of occurrences of `min' and
  1061 `max', and `-' on `nat'.
  1062 
  1063 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1064 (negated) (in)equalities among the premises and the conclusion into
  1065 account (i.e. no compound formulae) and does not know about `min' and
  1066 `max', and `-' on `nat'. It is fast and is used automatically by the
  1067 simplifier.
  1068 
  1069 NB: At the moment, these decision procedures do not cope with mixed
  1070 nat/int formulae where the two parts interact, such as `m < n ==>
  1071 int(m) < int(n)'.
  1072 
  1073 * HOL/Numeral provides a generic theory of numerals (encoded
  1074 efficiently as bit strings); setup for types nat/int/real is in place;
  1075 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1076 int, existing theories and proof scripts may require a few additional
  1077 type constraints;
  1078 
  1079 * integer division and remainder can now be performed on constant
  1080 arguments;
  1081 
  1082 * many properties of integer multiplication, division and remainder
  1083 are now available;
  1084 
  1085 * An interface to the Stanford Validity Checker (SVC) is available through the
  1086 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1087 are proved automatically.  SVC must be installed separately, and its results
  1088 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1089 invocation of the underlying oracle).  For SVC see
  1090   http://verify.stanford.edu/SVC
  1091 
  1092 * IsaMakefile: the HOL-Real target now builds an actual image;
  1093 
  1094 
  1095 ** HOL misc **
  1096 
  1097 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1098 (in Isabelle/Isar) -- by Gertrud Bauer;
  1099 
  1100 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1101 analysis for assembly languages with subtypes;
  1102 
  1103 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1104 -- avoids syntactic ambiguities and treats state, transition, and
  1105 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1106 changed syntax and (many) tactics;
  1107 
  1108 * HOL/inductive: Now also handles more general introduction rules such
  1109   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1110   theorems are now maintained within the theory (maintained via the
  1111   "mono" attribute);
  1112 
  1113 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1114   (using function types) such as
  1115 
  1116   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1117 
  1118 * HOL/record: record_simproc (part of the default simpset) takes care
  1119 of selectors applied to updated records; record_split_tac is no longer
  1120 part of the default claset; update_defs may now be removed from the
  1121 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1122 
  1123   claset_ref () := claset() addSWrapper record_split_wrapper;
  1124   Delsimprocs [record_simproc]
  1125 
  1126 * HOL/typedef: fixed type inference for representing set; type
  1127 arguments now have to occur explicitly on the rhs as type constraints;
  1128 
  1129 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1130 names rather than an ML expression;
  1131 
  1132 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1133 supplied later.  Program schemes can be defined, such as
  1134     "While B C s = (if B s then While B C (C s) else s)"
  1135 where the well-founded relation can be chosen after B and C have been given.
  1136 
  1137 * HOL/List: the constructors of type list are now Nil and Cons;
  1138 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1139 course, ML tools referring to List.list.op # etc. have to be adapted;
  1140 
  1141 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1142 disabled by default; run isabelle with option -m HOL to get back to
  1143 the original Gordon/HOL-style output;
  1144 
  1145 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1146 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1147 
  1148 * HOL basic syntax simplified (more orthogonal): all variants of
  1149 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1150 Eps operator is provided as well: "SOME x. P[x]";
  1151 
  1152 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1153 
  1154 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1155 thus available for user theories;
  1156 
  1157 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1158 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1159 time;
  1160 
  1161 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1162 several times and then mp;
  1163 
  1164 
  1165 *** LK ***
  1166 
  1167 * the notation <<...>> is now available as a notation for sequences of
  1168 formulas;
  1169 
  1170 * the simplifier is now installed
  1171 
  1172 * the axiom system has been generalized (thanks to Soren Heilmann)
  1173 
  1174 * the classical reasoner now has a default rule database
  1175 
  1176 
  1177 *** ZF ***
  1178 
  1179 * new primrec section allows primitive recursive functions to be given
  1180 directly (as in HOL) over datatypes and the natural numbers;
  1181 
  1182 * new tactics induct_tac and exhaust_tac for induction (or case
  1183 analysis) over datatypes and the natural numbers;
  1184 
  1185 * the datatype declaration of type T now defines the recursor T_rec;
  1186 
  1187 * simplification automatically does freeness reasoning for datatype
  1188 constructors;
  1189 
  1190 * automatic type-inference, with AddTCs command to insert new
  1191 type-checking rules;
  1192 
  1193 * datatype introduction rules are now added as Safe Introduction rules
  1194 to the claset;
  1195 
  1196 * the syntax "if P then x else y" is now available in addition to
  1197 if(P,x,y);
  1198 
  1199 
  1200 *** Internal programming interfaces ***
  1201 
  1202 * tuned simplifier trace output; new flag debug_simp;
  1203 
  1204 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1205 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1206 
  1207 * AxClass.axclass_tac lost the theory argument;
  1208 
  1209 * tuned current_goals_markers semantics: begin / end goal avoids
  1210 printing empty lines;
  1211 
  1212 * removed prs and prs_fn hook, which was broken because it did not
  1213 include \n in its semantics, forcing writeln to add one
  1214 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1215 string -> unit if you really want to output text without newline;
  1216 
  1217 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1218 plain output, interface builders may have to enable 'isabelle_font'
  1219 mode to get Isabelle font glyphs as before;
  1220 
  1221 * refined token_translation interface; INCOMPATIBILITY: output length
  1222 now of type real instead of int;
  1223 
  1224 * theory loader actions may be traced via new ThyInfo.add_hook
  1225 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1226 your own database of information attached to *whole* theories -- as
  1227 opposed to intra-theory data slots offered via TheoryDataFun;
  1228 
  1229 * proper handling of dangling sort hypotheses (at last!);
  1230 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1231 extra sort hypotheses that can be witnessed from the type signature;
  1232 the force_strip_shyps flag is gone, any remaining shyps are simply
  1233 left in the theorem (with a warning issued by strip_shyps_warning);
  1234 
  1235 
  1236 
  1237 New in Isabelle98-1 (October 1998)
  1238 ----------------------------------
  1239 
  1240 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1241 
  1242 * several changes of automated proof tools;
  1243 
  1244 * HOL: major changes to the inductive and datatype packages, including
  1245 some minor incompatibilities of theory syntax;
  1246 
  1247 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1248 called `inj_on';
  1249 
  1250 * HOL: removed duplicate thms in Arith:
  1251   less_imp_add_less  should be replaced by  trans_less_add1
  1252   le_imp_add_le      should be replaced by  trans_le_add1
  1253 
  1254 * HOL: unary minus is now overloaded (new type constraints may be
  1255 required);
  1256 
  1257 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1258 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1259 now taken as an integer constant.
  1260 
  1261 * Pure: ML function 'theory_of' renamed to 'theory';
  1262 
  1263 
  1264 *** Proof tools ***
  1265 
  1266 * Simplifier:
  1267   1. Asm_full_simp_tac is now more aggressive.
  1268      1. It will sometimes reorient premises if that increases their power to
  1269         simplify.
  1270      2. It does no longer proceed strictly from left to right but may also
  1271         rotate premises to achieve further simplification.
  1272      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1273      old Asm_full_simp_tac in that it does not rotate premises.
  1274   2. The simplifier now knows a little bit about nat-arithmetic.
  1275 
  1276 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1277 allows for selected deletion of wrappers, by introduction of names for
  1278 wrapper functionals.  This implies that addbefore, addSbefore,
  1279 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1280 and that adding two tactics with the same name overwrites the first
  1281 one (emitting a warning).
  1282   type wrapper = (int -> tactic) -> (int -> tactic)
  1283   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1284   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1285   delWrapper, delSWrapper: claset *  string            -> claset
  1286   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1287 
  1288 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1289 semantics; addbefore now affects only the unsafe part of step_tac
  1290 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1291 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1292 by Force_tac;
  1293 
  1294 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1295 compWrapper; added safe wrapper (and access functions for it);
  1296 
  1297 * HOL/split_all_tac is now much faster and fails if there is nothing
  1298 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1299 and the names of the automatically generated variables have changed.
  1300 split_all_tac has moved within claset() from unsafe wrappers to safe
  1301 wrappers, which means that !!-bound variables are split much more
  1302 aggressively, and safe_tac and clarify_tac now split such variables.
  1303 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1304 Note: the same holds for record_split_tac, which does the job of
  1305 split_all_tac for record fields.
  1306 
  1307 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1308 permanently to the default simpset using Addsplits just like
  1309 Addsimps. They can be removed via Delsplits just like
  1310 Delsimps. Lower-case versions are also available.
  1311 
  1312 * HOL/Simplifier: The rule split_if is now part of the default
  1313 simpset. This means that the simplifier will eliminate all occurrences
  1314 of if-then-else in the conclusion of a goal. To prevent this, you can
  1315 either remove split_if completely from the default simpset by
  1316 `Delsplits [split_if]' or remove it in a specific call of the
  1317 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1318 other case splitting rules to/from the default simpset: every datatype
  1319 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1320 t is the name of the datatype).
  1321 
  1322 * Classical reasoner / Simplifier combination: new force_tac (and
  1323 derivatives Force_tac, force) combines rewriting and classical
  1324 reasoning (and whatever other tools) similarly to auto_tac, but is
  1325 aimed to solve the given subgoal completely.
  1326 
  1327 
  1328 *** General ***
  1329 
  1330 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1331 and `goalw': the theory is no longer needed as an explicit argument -
  1332 the current theory context is used; assumptions are no longer returned
  1333 at the ML-level unless one of them starts with ==> or !!; it is
  1334 recommended to convert to these new commands using isatool fixgoal
  1335 (backup your sources first!);
  1336 
  1337 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1338 the current theory context, and 'theory' to lookup stored theories;
  1339 
  1340 * new theory section 'locale' for declaring constants, assumptions and
  1341 definitions that have local scope;
  1342 
  1343 * new theory section 'nonterminals' for purely syntactic types;
  1344 
  1345 * new theory section 'setup' for generic ML setup functions
  1346 (e.g. package initialization);
  1347 
  1348 * the distribution now includes Isabelle icons: see
  1349 lib/logo/isabelle-{small,tiny}.xpm;
  1350 
  1351 * isatool install - install binaries with absolute references to
  1352 ISABELLE_HOME/bin;
  1353 
  1354 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1355 
  1356 * print mode 'emacs' reserved for Isamode;
  1357 
  1358 * support multiple print (ast) translations per constant name;
  1359 
  1360 * theorems involving oracles are now printed with a suffixed [!];
  1361 
  1362 
  1363 *** HOL ***
  1364 
  1365 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1366 
  1367 * HOL/inductive package reorganized and improved: now supports mutual
  1368 definitions such as
  1369 
  1370   inductive EVEN ODD
  1371     intrs
  1372       null "0 : EVEN"
  1373       oddI "n : EVEN ==> Suc n : ODD"
  1374       evenI "n : ODD ==> Suc n : EVEN"
  1375 
  1376 new theorem list "elims" contains an elimination rule for each of the
  1377 recursive sets; inductive definitions now handle disjunctive premises
  1378 correctly (also ZF);
  1379 
  1380 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1381 "mutual_induct" no longer exists - the induction rule is always
  1382 contained in "induct";
  1383 
  1384 
  1385 * HOL/datatype package re-implemented and greatly improved: now
  1386 supports mutually recursive datatypes such as
  1387 
  1388   datatype
  1389     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1390             | SUM ('a aexp) ('a aexp)
  1391             | DIFF ('a aexp) ('a aexp)
  1392             | NUM 'a
  1393   and
  1394     'a bexp = LESS ('a aexp) ('a aexp)
  1395             | AND ('a bexp) ('a bexp)
  1396             | OR ('a bexp) ('a bexp)
  1397 
  1398 as well as indirectly recursive datatypes such as
  1399 
  1400   datatype
  1401     ('a, 'b) term = Var 'a
  1402                   | App 'b ((('a, 'b) term) list)
  1403 
  1404 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1405 induction on mutually / indirectly recursive datatypes.
  1406 
  1407 Primrec equations are now stored in theory and can be accessed via
  1408 <function_name>.simps.
  1409 
  1410 INCOMPATIBILITIES:
  1411 
  1412   - Theories using datatypes must now have theory Datatype as an
  1413     ancestor.
  1414   - The specific <typename>.induct_tac no longer exists - use the
  1415     generic induct_tac instead.
  1416   - natE has been renamed to nat.exhaust - use exhaust_tac
  1417     instead of res_inst_tac ... natE. Note that the variable
  1418     names in nat.exhaust differ from the names in natE, this
  1419     may cause some "fragile" proofs to fail.
  1420   - The theorems split_<typename>_case and split_<typename>_case_asm
  1421     have been renamed to <typename>.split and <typename>.split_asm.
  1422   - Since default sorts of type variables are now handled correctly,
  1423     some datatype definitions may have to be annotated with explicit
  1424     sort constraints.
  1425   - Primrec definitions no longer require function name and type
  1426     of recursive argument.
  1427 
  1428 Consider using isatool fixdatatype to adapt your theories and proof
  1429 scripts to the new package (backup your sources first!).
  1430 
  1431 
  1432 * HOL/record package: considerably improved implementation; now
  1433 includes concrete syntax for record types, terms, updates; theorems
  1434 for surjective pairing and splitting !!-bound record variables; proof
  1435 support is as follows:
  1436 
  1437   1) standard conversions (selectors or updates applied to record
  1438 constructor terms) are part of the standard simpset;
  1439 
  1440   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1441 made part of standard simpset and claset via addIffs;
  1442 
  1443   3) a tactic for record field splitting (record_split_tac) is part of
  1444 the standard claset (addSWrapper);
  1445 
  1446 To get a better idea about these rules you may retrieve them via
  1447 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1448 the name of your record type.
  1449 
  1450 The split tactic 3) conceptually simplifies by the following rule:
  1451 
  1452   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1453 
  1454 Thus any record variable that is bound by meta-all will automatically
  1455 blow up into some record constructor term, consequently the
  1456 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1457 solve record problems automatically.
  1458 
  1459 
  1460 * reorganized the main HOL image: HOL/Integ and String loaded by
  1461 default; theory Main includes everything;
  1462 
  1463 * automatic simplification of integer sums and comparisons, using cancellation;
  1464 
  1465 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1466 
  1467 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1468 
  1469 * many new identities for unions, intersections, set difference, etc.;
  1470 
  1471 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1472 called split_if, split_split, split_sum_case and split_nat_case (to go
  1473 with add/delsplits);
  1474 
  1475 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1476 (?x::unit) = (); this is made part of the default simpset, which COULD
  1477 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1478 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1479 unit_abs_eta_conv is added in order to counter the effect of
  1480 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1481 %u.f();
  1482 
  1483 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1484 makes more sense);
  1485 
  1486 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1487   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1488   disjointness reasoning but breaking a few old proofs.
  1489 
  1490 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1491 to 'converse' from 'inverse' (for compatibility with ZF and some
  1492 literature);
  1493 
  1494 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1495 the well-founded relation;
  1496 
  1497 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1498     Compl A.  The "Compl" syntax remains available as input syntax for this
  1499     release ONLY.
  1500 
  1501 * HOL/Update: new theory of function updates:
  1502     f(a:=b) == %x. if x=a then b else f x
  1503 may also be iterated as in f(a:=b,c:=d,...);
  1504 
  1505 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1506 
  1507 * HOL/List:
  1508   - new function list_update written xs[i:=v] that updates the i-th
  1509     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1510   - new function `upt' written [i..j(] which generates the list
  1511     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1512     bound write [i..j], which is a shorthand for [i..j+1(].
  1513   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1514 
  1515 * HOL/Arith:
  1516   - removed 'pred' (predecessor) function;
  1517   - generalized some theorems about n-1;
  1518   - many new laws about "div" and "mod";
  1519   - new laws about greatest common divisors (see theory ex/Primes);
  1520 
  1521 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1522 instead of "inverse";
  1523 
  1524 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1525   of the multiset ordering;
  1526 
  1527 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1528   (not included by default);
  1529 
  1530 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1531 
  1532 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1533   programs, i.e. different program variables may have different types.
  1534 
  1535 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1536   [previously, this check worked only if the rewrite rule was unconditional]
  1537   Now rew can involve either definitions or equalities (either == or =).
  1538 
  1539 
  1540 *** ZF ***
  1541 
  1542 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1543   only the theorems proved on ZF.ML;
  1544 
  1545 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1546   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1547   disjointness reasoning but breaking a few old proofs.
  1548 
  1549 * ZF/Update: new theory of function updates
  1550     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1551   may also be iterated as in f(a:=b,c:=d,...);
  1552 
  1553 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1554 
  1555 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1556   [previously, this check worked only if the rewrite rule was unconditional]
  1557   Now rew can involve either definitions or equalities (either == or =).
  1558 
  1559 * case_tac provided for compatibility with HOL
  1560     (like the old excluded_middle_tac, but with subgoals swapped)
  1561 
  1562 
  1563 *** Internal programming interfaces ***
  1564 
  1565 * Pure: several new basic modules made available for general use, see
  1566 also src/Pure/README;
  1567 
  1568 * improved the theory data mechanism to support encapsulation (data
  1569 kind name replaced by private Object.kind, acting as authorization
  1570 key); new type-safe user interface via functor TheoryDataFun; generic
  1571 print_data function becomes basically useless;
  1572 
  1573 * removed global_names compatibility flag -- all theory declarations
  1574 are qualified by default;
  1575 
  1576 * module Pure/Syntax now offers quote / antiquote translation
  1577 functions (useful for Hoare logic etc. with implicit dependencies);
  1578 see HOL/ex/Antiquote for an example use;
  1579 
  1580 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1581 cterm -> thm;
  1582 
  1583 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1584 subgoal;
  1585 
  1586 * Display.print_goals function moved to Locale.print_goals;
  1587 
  1588 * standard print function for goals supports current_goals_markers
  1589 variable for marking begin of proof, end of proof, start of goal; the
  1590 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1591 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1592 for example;
  1593 
  1594 
  1595 
  1596 New in Isabelle98 (January 1998)
  1597 --------------------------------
  1598 
  1599 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1600 
  1601 * changed lexical syntax of terms / types: dots made part of long
  1602 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1603 
  1604 * simpset (and claset) reference variable replaced by functions
  1605 simpset / simpset_ref;
  1606 
  1607 * no longer supports theory aliases (via merge) and non-trivial
  1608 implicit merge of thms' signatures;
  1609 
  1610 * most internal names of constants changed due to qualified names;
  1611 
  1612 * changed Pure/Sequence interface (see Pure/seq.ML);
  1613 
  1614 
  1615 *** General Changes ***
  1616 
  1617 * hierachically structured name spaces (for consts, types, axms, thms
  1618 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1619 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1620 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1621 long_names for fully qualified output names; NOTE: ML programs
  1622 (special tactics, packages etc.) referring to internal names may have
  1623 to be adapted to cope with fully qualified names; in case of severe
  1624 backward campatibility problems try setting 'global_names' at compile
  1625 time to have enrything declared within a flat name space; one may also
  1626 fine tune name declarations in theories via the 'global' and 'local'
  1627 section;
  1628 
  1629 * reimplemented the implicit simpset and claset using the new anytype
  1630 data filed in signatures; references simpset:simpset ref etc. are
  1631 replaced by functions simpset:unit->simpset and
  1632 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1633 to patch your ML files accordingly;
  1634 
  1635 * HTML output now includes theory graph data for display with Java
  1636 applet or isatool browser; data generated automatically via isatool
  1637 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1638 
  1639 * defs may now be conditional; improved rewrite_goals_tac to handle
  1640 conditional equations;
  1641 
  1642 * defs now admits additional type arguments, using TYPE('a) syntax;
  1643 
  1644 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1645 creates a new theory node; implicit merge of thms' signatures is
  1646 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1647 transfer:theory->thm->thm in (rare) cases;
  1648 
  1649 * improved handling of draft signatures / theories; draft thms (and
  1650 ctyps, cterms) are automatically promoted to real ones;
  1651 
  1652 * slightly changed interfaces for oracles: admit many per theory, named
  1653 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1654 
  1655 * print_goals: optional output of const types (set show_consts and
  1656 show_types);
  1657 
  1658 * improved output of warnings (###) and errors (***);
  1659 
  1660 * subgoal_tac displays a warning if the new subgoal has type variables;
  1661 
  1662 * removed old README and Makefiles;
  1663 
  1664 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1665 
  1666 * removed obsolete init_pps and init_database;
  1667 
  1668 * deleted the obsolete tactical STATE, which was declared by
  1669     fun STATE tacfun st = tacfun st st;
  1670 
  1671 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1672 (which abbreviates $HOME);
  1673 
  1674 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1675 use isatool fixseq to adapt your ML programs (this works for fully
  1676 qualified references to the Sequence structure only!);
  1677 
  1678 * use_thy no longer requires writable current directory; it always
  1679 reloads .ML *and* .thy file, if either one is out of date;
  1680 
  1681 
  1682 *** Classical Reasoner ***
  1683 
  1684 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1685 tactics that use classical reasoning to simplify a subgoal without
  1686 splitting it into several subgoals;
  1687 
  1688 * Safe_tac: like safe_tac but uses the default claset;
  1689 
  1690 
  1691 *** Simplifier ***
  1692 
  1693 * added simplification meta rules:
  1694     (asm_)(full_)simplify: simpset -> thm -> thm;
  1695 
  1696 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1697 logics (again);
  1698 
  1699 * added prems argument to simplification procedures;
  1700 
  1701 * HOL, FOL, ZF: added infix function `addsplits':
  1702   instead of `<simpset> setloop (split_tac <thms>)'
  1703   you can simply write `<simpset> addsplits <thms>'
  1704 
  1705 
  1706 *** Syntax ***
  1707 
  1708 * TYPE('a) syntax for type reflection terms;
  1709 
  1710 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1711 
  1712 * pretty printer: changed order of mixfix annotation preference (again!);
  1713 
  1714 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1715 
  1716 
  1717 *** HOL ***
  1718 
  1719 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1720   with `addloop' of the simplifier to faciliate case splitting in premises.
  1721 
  1722 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1723 
  1724 * HOL/Auth: new protocol proofs including some for the Internet
  1725   protocol TLS;
  1726 
  1727 * HOL/Map: new theory of `maps' a la VDM;
  1728 
  1729 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1730 cancelling out common nat summands from =, <, <= (in)equalities, or
  1731 differences; simplification procedures nat_cancel_factor for
  1732 cancelling common factor from =, <, <= (in)equalities over natural
  1733 sums; nat_cancel contains both kinds of procedures, it is installed by
  1734 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1735 
  1736 * HOL/simplifier: terms of the form
  1737   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1738   are rewritten to
  1739   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1740   and those of the form
  1741   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1742   are rewritten to
  1743   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1744 
  1745 * HOL/datatype
  1746   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1747 
  1748   P(t_case f1 ... fn x) =
  1749      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1750         ...
  1751        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1752      )
  1753 
  1754   and a theorem `split_t_case_asm' of the form
  1755 
  1756   P(t_case f1 ... fn x) =
  1757     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1758         ...
  1759        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1760      )
  1761   which can be added to a simpset via `addsplits'. The existing theorems
  1762   expand_list_case and expand_option_case have been renamed to
  1763   split_list_case and split_option_case.
  1764 
  1765 * HOL/Arithmetic:
  1766   - `pred n' is automatically converted to `n-1'.
  1767     Users are strongly encouraged not to use `pred' any longer,
  1768     because it will disappear altogether at some point.
  1769   - Users are strongly encouraged to write "0 < n" rather than
  1770     "n ~= 0". Theorems and proof tools have been modified towards this
  1771     `standard'.
  1772 
  1773 * HOL/Lists:
  1774   the function "set_of_list" has been renamed "set" (and its theorems too);
  1775   the function "nth" now takes its arguments in the reverse order and
  1776   has acquired the infix notation "!" as in "xs!n".
  1777 
  1778 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1779 
  1780 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1781   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1782 
  1783 * HOL/record: extensible records with schematic structural subtyping
  1784 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1785 still lacks various theorems and concrete record syntax;
  1786 
  1787 
  1788 *** HOLCF ***
  1789 
  1790 * removed "axioms" and "generated by" sections;
  1791 
  1792 * replaced "ops" section by extended "consts" section, which is capable of
  1793   handling the continuous function space "->" directly;
  1794 
  1795 * domain package:
  1796   . proves theorems immediately and stores them in the theory,
  1797   . creates hierachical name space,
  1798   . now uses normal mixfix annotations (instead of cinfix...),
  1799   . minor changes to some names and values (for consistency),
  1800   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1801   . separator between mutual domain defs: changed "," to "and",
  1802   . improved handling of sort constraints;  now they have to
  1803     appear on the left-hand side of the equations only;
  1804 
  1805 * fixed LAM <x,y,zs>.b syntax;
  1806 
  1807 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1808 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1809 
  1810 
  1811 *** FOL and ZF ***
  1812 
  1813 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1814   with `addloop' of the simplifier to faciliate case splitting in premises.
  1815 
  1816 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1817 in HOL, they strip ALL and --> from proved theorems;
  1818 
  1819 
  1820 
  1821 New in Isabelle94-8 (May 1997)
  1822 ------------------------------
  1823 
  1824 *** General Changes ***
  1825 
  1826 * new utilities to build / run / maintain Isabelle etc. (in parts
  1827 still somewhat experimental); old Makefiles etc. still functional;
  1828 
  1829 * new 'Isabelle System Manual';
  1830 
  1831 * INSTALL text, together with ./configure and ./build scripts;
  1832 
  1833 * reimplemented type inference for greater efficiency, better error
  1834 messages and clean internal interface;
  1835 
  1836 * prlim command for dealing with lots of subgoals (an easier way of
  1837 setting goals_limit);
  1838 
  1839 
  1840 *** Syntax ***
  1841 
  1842 * supports alternative (named) syntax tables (parser and pretty
  1843 printer); internal interface is provided by add_modesyntax(_i);
  1844 
  1845 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1846 be used in conjunction with the Isabelle symbol font; uses the
  1847 "symbols" syntax table;
  1848 
  1849 * added token_translation interface (may translate name tokens in
  1850 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1851 the current print_mode); IMPORTANT: user print translation functions
  1852 are responsible for marking newly introduced bounds
  1853 (Syntax.mark_boundT);
  1854 
  1855 * token translations for modes "xterm" and "xterm_color" that display
  1856 names in bold, underline etc. or colors (which requires a color
  1857 version of xterm);
  1858 
  1859 * infixes may now be declared with names independent of their syntax;
  1860 
  1861 * added typed_print_translation (like print_translation, but may
  1862 access type of constant);
  1863 
  1864 
  1865 *** Classical Reasoner ***
  1866 
  1867 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1868 some limitations.  Blast_tac...
  1869   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1870   + ignores elimination rules that don't have the correct format
  1871         (the conclusion MUST be a formula variable)
  1872   + ignores types, which can make HOL proofs fail
  1873   + rules must not require higher-order unification, e.g. apply_type in ZF
  1874     [message "Function Var's argument not a bound variable" relates to this]
  1875   + its proof strategy is more general but can actually be slower
  1876 
  1877 * substitution with equality assumptions no longer permutes other
  1878 assumptions;
  1879 
  1880 * minor changes in semantics of addafter (now called addaltern); renamed
  1881 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1882 (and access functions for it);
  1883 
  1884 * improved combination of classical reasoner and simplifier:
  1885   + functions for handling clasimpsets
  1886   + improvement of addss: now the simplifier is called _after_ the
  1887     safe steps.
  1888   + safe variant of addss called addSss: uses safe simplifications
  1889     _during_ the safe steps. It is more complete as it allows multiple
  1890     instantiations of unknowns (e.g. with slow_tac).
  1891 
  1892 *** Simplifier ***
  1893 
  1894 * added interface for simplification procedures (functions that
  1895 produce *proven* rewrite rules on the fly, depending on current
  1896 redex);
  1897 
  1898 * ordering on terms as parameter (used for ordered rewriting);
  1899 
  1900 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1901 
  1902 * the solver is now split into a safe and an unsafe part.
  1903 This should be invisible for the normal user, except that the
  1904 functions setsolver and addsolver have been renamed to setSolver and
  1905 addSolver; added safe_asm_full_simp_tac;
  1906 
  1907 
  1908 *** HOL ***
  1909 
  1910 * a generic induction tactic `induct_tac' which works for all datatypes and
  1911 also for type `nat';
  1912 
  1913 * a generic case distinction tactic `exhaust_tac' which works for all
  1914 datatypes and also for type `nat';
  1915 
  1916 * each datatype comes with a function `size';
  1917 
  1918 * patterns in case expressions allow tuple patterns as arguments to
  1919 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1920 
  1921 * primrec now also works with type nat;
  1922 
  1923 * recdef: a new declaration form, allows general recursive functions to be
  1924 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1925 
  1926 * the constant for negation has been renamed from "not" to "Not" to
  1927 harmonize with FOL, ZF, LK, etc.;
  1928 
  1929 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1930 infinite lists;
  1931 
  1932 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1933 
  1934 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1935 problems in commutative rings, using axiomatic type classes for + and *;
  1936 
  1937 * more examples in HOL/MiniML and HOL/Auth;
  1938 
  1939 * more default rewrite rules for quantifiers, union/intersection;
  1940 
  1941 * a new constant `arbitrary == @x.False';
  1942 
  1943 * HOLCF/IOA replaces old HOL/IOA;
  1944 
  1945 * HOLCF changes: derived all rules and arities
  1946   + axiomatic type classes instead of classes
  1947   + typedef instead of faking type definitions
  1948   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1949   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1950   + eliminated the types void, one, tr
  1951   + use unit lift and bool lift (with translations) instead of one and tr
  1952   + eliminated blift from Lift3.thy (use Def instead of blift)
  1953   all eliminated rules are derived as theorems --> no visible changes ;
  1954 
  1955 
  1956 *** ZF ***
  1957 
  1958 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1959 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1960 as ZF_cs addSIs [equalityI];
  1961 
  1962 
  1963 
  1964 New in Isabelle94-7 (November 96)
  1965 ---------------------------------
  1966 
  1967 * allowing negative levels (as offsets) in prlev and choplev;
  1968 
  1969 * super-linear speedup for large simplifications;
  1970 
  1971 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1972 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1973 FAIL); can suppress it using the command Delsimps (ex_simps @
  1974 all_simps); De Morgan laws are also now included, by default;
  1975 
  1976 * improved printing of ==>  :  ~:
  1977 
  1978 * new object-logic "Sequents" adds linear logic, while replacing LK
  1979 and Modal (thanks to Sara Kalvala);
  1980 
  1981 * HOL/Auth: correctness proofs for authentication protocols;
  1982 
  1983 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1984 examples on HOL/Auth);
  1985 
  1986 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1987 the rewriter and classical reasoner simultaneously;
  1988 
  1989 * function uresult no longer returns theorems in "standard" format;
  1990 regain previous version by: val uresult = standard o uresult;
  1991 
  1992 
  1993 
  1994 New in Isabelle94-6
  1995 -------------------
  1996 
  1997 * oracles -- these establish an interface between Isabelle and trusted
  1998 external reasoners, which may deliver results as theorems;
  1999 
  2000 * proof objects (in particular record all uses of oracles);
  2001 
  2002 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2003 
  2004 * "constdefs" section in theory files;
  2005 
  2006 * "primrec" section (HOL) no longer requires names;
  2007 
  2008 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2009 
  2010 
  2011 
  2012 New in Isabelle94-5
  2013 -------------------
  2014 
  2015 * reduced space requirements;
  2016 
  2017 * automatic HTML generation from theories;
  2018 
  2019 * theory files no longer require "..." (quotes) around most types;
  2020 
  2021 * new examples, including two proofs of the Church-Rosser theorem;
  2022 
  2023 * non-curried (1994) version of HOL is no longer distributed;
  2024 
  2025 
  2026 
  2027 New in Isabelle94-4
  2028 -------------------
  2029 
  2030 * greatly reduced space requirements;
  2031 
  2032 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2033 
  2034 * searchable theorem database (see the section "Retrieving theorems" on
  2035 page 8 of the Reference Manual);
  2036 
  2037 * new examples, including Grabczewski's monumental case study of the
  2038 Axiom of Choice;
  2039 
  2040 * The previous version of HOL renamed to Old_HOL;
  2041 
  2042 * The new version of HOL (previously called CHOL) uses a curried syntax
  2043 for functions.  Application looks like f a b instead of f(a,b);
  2044 
  2045 * Mutually recursive inductive definitions finally work in HOL;
  2046 
  2047 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2048 translates to the operator "split";
  2049 
  2050 
  2051 
  2052 New in Isabelle94-3
  2053 -------------------
  2054 
  2055 * new infix operator, addss, allowing the classical reasoner to
  2056 perform simplification at each step of its search.  Example:
  2057         fast_tac (cs addss ss)
  2058 
  2059 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2060 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2061 look like (a,b) instead of <a,b>;
  2062 
  2063 * PLEASE NOTE: CHOL will eventually replace HOL!
  2064 
  2065 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2066 It translates to the operator "split".  A new theory of integers is available;
  2067 
  2068 * In ZF, integer numerals now denote two's-complement binary integers.
  2069 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2070 
  2071 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2072 of the Axiom of Choice;
  2073 
  2074 
  2075 
  2076 New in Isabelle94-2
  2077 -------------------
  2078 
  2079 * Significantly faster resolution;
  2080 
  2081 * the different sections in a .thy file can now be mixed and repeated
  2082 freely;
  2083 
  2084 * Database of theorems for FOL, HOL and ZF.  New
  2085 commands including qed, qed_goal and bind_thm store theorems in the database.
  2086 
  2087 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2088 a given theory (thms_of), or find out what theory a theorem was proved in
  2089 (theory_of_thm);
  2090 
  2091 * Bugs fixed in the inductive definition and datatype packages;
  2092 
  2093 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2094 and HOL_dup_cs obsolete;
  2095 
  2096 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2097 have been removed;
  2098 
  2099 * Simpler definition of function space in ZF;
  2100 
  2101 * new results about cardinal and ordinal arithmetic in ZF;
  2102 
  2103 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2104 types;
  2105 
  2106 
  2107 $Id$