NEWS
author wenzelm
Tue Dec 11 17:07:45 2001 +0100 (2001-12-11)
changeset 12472 3307149f1ec2
parent 12467 b5630a4ea5d8
child 12489 c92e38c3cbaa
permissions -rw-r--r--
tuned;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (December 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: support Poly/ML 4.1.1 (able to manage larger heaps);
   301 
   302 * system: Proof General keywords specification is now part of the
   303 Isabelle distribution (see etc/isar-keywords.el);
   304 
   305 * system: smart selection of Isabelle process versus Isabelle
   306 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   307 run both "isabelle" and "Isabelle" even if file names are badly
   308 damaged (executable inspects the case of the first letter of its own
   309 name); added separate "isabelle-process" and "isabelle-interface";
   310 
   311 * system: refrain from any attempt at filtering input streams; no
   312 longer support ``8bit'' encoding of old isabelle font, instead proper
   313 iso-latin characters may now be used; the related isatools
   314 "symbolinput" and "nonascii" have disappeared as well;
   315 
   316 * system: removed old "xterm" interface (the print modes "xterm" and
   317 "xterm_color" are still available for direct use in a suitable
   318 terminal);
   319 
   320 
   321 
   322 New in Isabelle99-2 (February 2001)
   323 -----------------------------------
   324 
   325 *** Overview of INCOMPATIBILITIES ***
   326 
   327 * HOL: please note that theories in the Library and elsewhere often use the
   328 new-style (Isar) format; to refer to their theorems in an ML script you must
   329 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   330 
   331 * HOL: inductive package no longer splits induction rule aggressively,
   332 but only as far as specified by the introductions given; the old
   333 format may be recovered via ML function complete_split_rule or attribute
   334 'split_rule (complete)';
   335 
   336 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   337 gfp_Tarski to gfp_unfold;
   338 
   339 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   340 
   341 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   342 relation); infix "^^" has been renamed "``"; infix "``" has been
   343 renamed "`"; "univalent" has been renamed "single_valued";
   344 
   345 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   346 operation;
   347 
   348 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   349 
   350 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   351 
   352 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   353 consequence, it is no longer monotonic wrt. the local goal context
   354 (which is now passed through the inductive cases);
   355 
   356 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   357 \<gg> to \<ggreater>;
   358 
   359 
   360 *** Document preparation ***
   361 
   362 * \isabellestyle{NAME} selects version of Isabelle output (currently
   363 available: are "it" for near math-mode best-style output, "sl" for
   364 slanted text style, and "tt" for plain type-writer; if no
   365 \isabellestyle command is given, output is according to slanted
   366 type-writer);
   367 
   368 * support sub/super scripts (for single symbols only), input syntax is
   369 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   370 
   371 * some more standard symbols; see Appendix A of the system manual for
   372 the complete list of symbols defined in isabellesym.sty;
   373 
   374 * improved isabelle style files; more abstract symbol implementation
   375 (should now use \isamath{...} and \isatext{...} in custom symbol
   376 definitions);
   377 
   378 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   379 state; Note that presentation of goal states does not conform to
   380 actual human-readable proof documents.  Please do not include goal
   381 states into document output unless you really know what you are doing!
   382 
   383 * proper indentation of antiquoted output with proportional LaTeX
   384 fonts;
   385 
   386 * no_document ML operator temporarily disables LaTeX document
   387 generation;
   388 
   389 * isatool unsymbolize tunes sources for plain ASCII communication;
   390 
   391 
   392 *** Isar ***
   393 
   394 * Pure: Isar now suffers initial goal statements to contain unbound
   395 schematic variables (this does not conform to actual readable proof
   396 documents, due to unpredictable outcome and non-compositional proof
   397 checking); users who know what they are doing may use schematic goals
   398 for Prolog-style synthesis of proven results;
   399 
   400 * Pure: assumption method (an implicit finishing) now handles actual
   401 rules as well;
   402 
   403 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   404 initial goal, declare "that" only as Pure intro (only for single
   405 steps); the "that" rule assumption may now be involved in implicit
   406 finishing, thus ".." becomes a feasible for trivial obtains;
   407 
   408 * Pure: default proof step now includes 'intro_classes'; thus trivial
   409 instance proofs may be performed by "..";
   410 
   411 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   412 statements as well;
   413 
   414 * Pure: more robust selection of calculational rules;
   415 
   416 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   417 rule (as well as the assumption rule);
   418 
   419 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   420 lemmas, using the graph browser tool;
   421 
   422 * Pure: predict failure of "show" in interactive mode;
   423 
   424 * Pure: 'thms_containing' now takes actual terms as arguments;
   425 
   426 * HOL: improved method 'induct' --- now handles non-atomic goals
   427 (potential INCOMPATIBILITY); tuned error handling;
   428 
   429 * HOL: cases and induct rules now provide explicit hints about the
   430 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   431 any remaining facts are inserted into the goal verbatim;
   432 
   433 * HOL: local contexts (aka cases) may now contain term bindings as
   434 well; the 'cases' and 'induct' methods new provide a ?case binding for
   435 the result to be shown in each case;
   436 
   437 * HOL: added 'recdef_tc' command;
   438 
   439 * isatool convert assists in eliminating legacy ML scripts;
   440 
   441 
   442 *** HOL ***
   443 
   444 * HOL/Library: a collection of generic theories to be used together
   445 with main HOL; the theory loader path already includes this directory
   446 by default; the following existing theories have been moved here:
   447 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   448 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   449 
   450 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   451 modelling and verification task performed in Isabelle/HOL +
   452 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   453 
   454 * HOL/Algebra: special summation operator SUM no longer exists, it has
   455 been replaced by setsum; infix 'assoc' now has priority 50 (like
   456 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   457 'domain', this makes the theory consistent with mathematical
   458 literature;
   459 
   460 * HOL basics: added overloaded operations "inverse" and "divide"
   461 (infix "/"), syntax for generic "abs" operation, generic summation
   462 operator \<Sum>;
   463 
   464 * HOL/typedef: simplified package, provide more useful rules (see also
   465 HOL/subset.thy);
   466 
   467 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   468 now expressed as a proper nested rule (old-style tactic scripts may
   469 require atomize_strip_tac to cope with non-atomic premises);
   470 
   471 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   472 to "split_conv" (old name still available for compatibility);
   473 
   474 * HOL: improved concrete syntax for strings (e.g. allows translation
   475 rules with string literals);
   476 
   477 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   478  and Fleuriot's mechanization of analysis, including the transcendental
   479  functions for the reals;
   480 
   481 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   482 
   483 
   484 *** CTT ***
   485 
   486 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   487 "lam" is displayed as TWO lambda-symbols
   488 
   489 * CTT: theory Main now available, containing everything (that is, Bool
   490 and Arith);
   491 
   492 
   493 *** General ***
   494 
   495 * Pure: the Simplifier has been implemented properly as a derived rule
   496 outside of the actual kernel (at last!); the overall performance
   497 penalty in practical applications is about 50%, while reliability of
   498 the Isabelle inference kernel has been greatly improved;
   499 
   500 * print modes "brackets" and "no_brackets" control output of nested =>
   501 (types) and ==> (props); the default behaviour is "brackets";
   502 
   503 * Provers: fast_tac (and friends) now handle actual object-logic rules
   504 as assumptions as well;
   505 
   506 * system: support Poly/ML 4.0;
   507 
   508 * system: isatool install handles KDE version 1 or 2;
   509 
   510 
   511 
   512 New in Isabelle99-1 (October 2000)
   513 ----------------------------------
   514 
   515 *** Overview of INCOMPATIBILITIES ***
   516 
   517 * HOL: simplification of natural numbers is much changed; to partly
   518 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   519 issue the following ML commands:
   520 
   521   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   522   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   523 
   524 * HOL: simplification no longer dives into case-expressions; this is
   525 controlled by "t.weak_case_cong" for each datatype t;
   526 
   527 * HOL: nat_less_induct renamed to less_induct;
   528 
   529 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   530 fixsome to patch .thy and .ML sources automatically;
   531 
   532   select_equality  -> some_equality
   533   select_eq_Ex     -> some_eq_ex
   534   selectI2EX       -> someI2_ex
   535   selectI2         -> someI2
   536   selectI          -> someI
   537   select1_equality -> some1_equality
   538   Eps_sym_eq       -> some_sym_eq_trivial
   539   Eps_eq           -> some_eq_trivial
   540 
   541 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   542 
   543 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   544 instead);
   545 
   546 * HOL: the recursion equations generated by 'recdef' are now called
   547 f.simps instead of f.rules;
   548 
   549 * HOL: qed_spec_mp now also handles bounded ALL as well;
   550 
   551 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   552 sometimes be needed;
   553 
   554 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   555 
   556 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   557 
   558 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   559 product is now "<*>" instead of "Times"; the lexicographic product is
   560 now "<*lex*>" instead of "**";
   561 
   562 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   563 of main HOL, but was unused); better use HOL's datatype package;
   564 
   565 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   566 the old syntax may be recovered as follows:
   567 
   568   syntax (symbols)
   569     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   570       (infixl "\\<oplus>" 100)
   571 
   572 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   573 
   574 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   575 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   576 internally;
   577 
   578 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   579 changed from A/r to A//r;
   580 
   581 * ZF: new treatment of arithmetic (nat & int) may break some old
   582 proofs;
   583 
   584 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   585 rulify -> rule_format, elimify -> elim_format, ...);
   586 
   587 * Isar/Provers: intro/elim/dest attributes changed; renamed
   588 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   589 should have to change intro!! to intro? only); replaced "delrule" by
   590 "rule del";
   591 
   592 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   593 
   594 * Provers: strengthened force_tac by using new first_best_tac;
   595 
   596 * LaTeX document preparation: several changes of isabelle.sty (see
   597 lib/texinputs);
   598 
   599 
   600 *** Document preparation ***
   601 
   602 * formal comments (text blocks etc.) in new-style theories may now
   603 contain antiquotations of thm/prop/term/typ/text to be presented
   604 according to latex print mode; concrete syntax is like this:
   605 @{term[show_types] "f(x) = a + x"};
   606 
   607 * isatool mkdir provides easy setup of Isabelle session directories,
   608 including proper document sources;
   609 
   610 * generated LaTeX sources are now deleted after successful run
   611 (isatool document -c); may retain a copy somewhere else via -D option
   612 of isatool usedir;
   613 
   614 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   615 style files, achieving self-contained LaTeX sources and simplifying
   616 LaTeX debugging;
   617 
   618 * old-style theories now produce (crude) LaTeX output as well;
   619 
   620 * browser info session directories are now self-contained (may be put
   621 on WWW server seperately); improved graphs of nested sessions; removed
   622 graph for 'all sessions';
   623 
   624 * several improvements in isabelle style files; \isabellestyle{it}
   625 produces fake math mode output; \isamarkupheader is now \section by
   626 default; see lib/texinputs/isabelle.sty etc.;
   627 
   628 
   629 *** Isar ***
   630 
   631 * Isar/Pure: local results and corresponding term bindings are now
   632 subject to Hindley-Milner polymorphism (similar to ML); this
   633 accommodates incremental type-inference very nicely;
   634 
   635 * Isar/Pure: new derived language element 'obtain' supports
   636 generalized existence reasoning;
   637 
   638 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   639 support accumulation of results, without applying any rules yet;
   640 useful to collect intermediate results without explicit name
   641 references, and for use with transitivity rules with more than 2
   642 premises;
   643 
   644 * Isar/Pure: scalable support for case-analysis type proofs: new
   645 'case' language element refers to local contexts symbolically, as
   646 produced by certain proof methods; internally, case names are attached
   647 to theorems as "tags";
   648 
   649 * Isar/Pure: theory command 'hide' removes declarations from
   650 class/type/const name spaces;
   651 
   652 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   653 indicate potential overloading;
   654 
   655 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   656 
   657 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   658 "{a,b,c}" instead of {a,b,c};
   659 
   660 * Isar/Pure now provides its own version of intro/elim/dest
   661 attributes; useful for building new logics, but beware of confusion
   662 with the version in Provers/classical;
   663 
   664 * Isar/Pure: the local context of (non-atomic) goals is provided via
   665 case name 'antecedent';
   666 
   667 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   668 to the current context is now done automatically);
   669 
   670 * Isar/Pure: theory command 'method_setup' provides a simple interface
   671 for definining proof methods in ML;
   672 
   673 * Isar/Provers: intro/elim/dest attributes changed; renamed
   674 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   675 most cases, one should have to change intro!! to intro? only);
   676 replaced "delrule" by "rule del";
   677 
   678 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   679 'symmetric' attribute (the latter supercedes [RS sym]);
   680 
   681 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   682 method modifier); 'simp' method: 'only:' modifier removes loopers as
   683 well (including splits);
   684 
   685 * Isar/Provers: Simplifier and Classical methods now support all kind
   686 of modifiers used in the past, including 'cong', 'iff', etc.
   687 
   688 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   689 of Simplifier and Classical reasoner);
   690 
   691 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   692 now support named cases; major packages (inductive, datatype, primrec,
   693 recdef) support case names and properly name parameters;
   694 
   695 * Isar/HOL: new transitivity rules for substitution in inequalities --
   696 monotonicity conditions are extracted to be proven at end of
   697 calculations;
   698 
   699 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   700 method anyway;
   701 
   702 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   703 split_if split_if_asm; datatype package provides theorems foo.splits =
   704 foo.split foo.split_asm for each datatype;
   705 
   706 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   707 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   708 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   709 use "(cases (simplified))" method in proper proof texts);
   710 
   711 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   712 
   713 * Isar: names of theorems etc. may be natural numbers as well;
   714 
   715 * Isar: 'pr' command: optional arguments for goals_limit and
   716 ProofContext.prems_limit; no longer prints theory contexts, but only
   717 proof states;
   718 
   719 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   720 additional print modes to be specified; e.g. "pr(latex)" will print
   721 proof state according to the Isabelle LaTeX style;
   722 
   723 * Isar: improved support for emulating tactic scripts, including proof
   724 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   725 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   726 (for HOL datatypes);
   727 
   728 * Isar: simplified (more robust) goal selection of proof methods: 1st
   729 goal, all goals, or explicit goal specifier (tactic emulation); thus
   730 'proof method scripts' have to be in depth-first order;
   731 
   732 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   733 
   734 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   735 should instead use individual commands for printing items
   736 (print_commands, print_methods etc.);
   737 
   738 * Isar: added 'nothing' --- the empty list of theorems;
   739 
   740 
   741 *** HOL ***
   742 
   743 * HOL/MicroJava: formalization of a fragment of Java, together with a
   744 corresponding virtual machine and a specification of its bytecode
   745 verifier and a lightweight bytecode verifier, including proofs of
   746 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   747 Cornelia Pusch (see also the homepage of project Bali at
   748 http://isabelle.in.tum.de/Bali/);
   749 
   750 * HOL/Algebra: new theory of rings and univariate polynomials, by
   751 Clemens Ballarin;
   752 
   753 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   754 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   755 Rasmussen;
   756 
   757 * HOL/Lattice: fundamental concepts of lattice theory and order
   758 structures, including duals, properties of bounds versus algebraic
   759 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   760 Theorem for complete lattices etc.; may also serve as a demonstration
   761 for abstract algebraic reasoning using axiomatic type classes, and
   762 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   763 
   764 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   765 von Oheimb;
   766 
   767 * HOL/IMPP: extension of IMP with local variables and mutually
   768 recursive procedures, by David von Oheimb;
   769 
   770 * HOL/Lambda: converted into new-style theory and document;
   771 
   772 * HOL/ex/Multiquote: example of multiple nested quotations and
   773 anti-quotations -- basically a generalized version of de-Bruijn
   774 representation; very useful in avoiding lifting of operations;
   775 
   776 * HOL/record: added general record equality rule to simpset; fixed
   777 select-update simplification procedure to handle extended records as
   778 well; admit "r" as field name;
   779 
   780 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   781 other numeric types and also as the identity of groups, rings, etc.;
   782 
   783 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   784 Types nat and int belong to this axclass;
   785 
   786 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   787    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   788    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   789   two terms #m*u and #n*u are replaced by #(m+n)*u
   790     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   791   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   792     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   793 
   794 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   795 powerful prover for predicate logic but knows nothing of clasets; see
   796 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   797 
   798 * HOL: new version of "case_tac" subsumes both boolean case split and
   799 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   800 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   801 
   802 * HOL: simplification no longer dives into case-expressions: only the
   803 selector expression is simplified, but not the remaining arms; to
   804 enable full simplification of case-expressions for datatype t, you may
   805 remove t.weak_case_cong from the simpset, either globally (Delcongs
   806 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   807 
   808 * HOL/recdef: the recursion equations generated by 'recdef' for
   809 function 'f' are now called f.simps instead of f.rules; if all
   810 termination conditions are proved automatically, these simplification
   811 rules are added to the simpset, as in primrec; rules may be named
   812 individually as well, resulting in a separate list of theorems for
   813 each equation;
   814 
   815 * HOL/While is a new theory that provides a while-combinator. It
   816 permits the definition of tail-recursive functions without the
   817 provision of a termination measure. The latter is necessary once the
   818 invariant proof rule for while is applied.
   819 
   820 * HOL: new (overloaded) notation for the set of elements below/above
   821 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   822 
   823 * HOL: theorems impI, allI, ballI bound as "strip";
   824 
   825 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   826 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   827 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   828 
   829 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   830 
   831 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   832 main HOL, but was unused);
   833 
   834 * HOL: fewer consts declared as global (e.g. have to refer to
   835 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   836 
   837 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   838 in case of overlap with user translations (e.g. judgements over
   839 tuples); (note that the underlying logical represenation is still
   840 bogus);
   841 
   842 
   843 *** ZF ***
   844 
   845 * ZF: simplification automatically cancels common terms in arithmetic
   846 expressions over nat and int;
   847 
   848 * ZF: new treatment of nat to minimize type-checking: all operators
   849 coerce their operands to a natural number using the function natify,
   850 making the algebraic laws unconditional;
   851 
   852 * ZF: as above, for int: operators coerce their operands to an integer
   853 using the function intify;
   854 
   855 * ZF: the integer library now contains many of the usual laws for the
   856 orderings, including $<=, and monotonicity laws for $+ and $*;
   857 
   858 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   859 simplification;
   860 
   861 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   862 to the simplifier and classical reasoner simultaneously;
   863 
   864 
   865 *** General ***
   866 
   867 * Provers: blast_tac now handles actual object-logic rules as
   868 assumptions; note that auto_tac uses blast_tac internally as well;
   869 
   870 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   871 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   872 
   873 * Provers: delrules now handles destruct rules as well (no longer need
   874 explicit make_elim);
   875 
   876 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   877   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   878 use instead the strong form,
   879   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   880 in HOL, FOL and ZF the function cla_make_elim will create such rules
   881 from destruct-rules;
   882 
   883 * Provers: Simplifier.easy_setup provides a fast path to basic
   884 Simplifier setup for new object-logics;
   885 
   886 * Pure: AST translation rules no longer require constant head on LHS;
   887 
   888 * Pure: improved name spaces: ambiguous output is qualified; support
   889 for hiding of names;
   890 
   891 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   892 XSYMBOL_HOME; no longer need to do manual configuration in most
   893 situations;
   894 
   895 * system: compression of ML heaps images may now be controlled via -c
   896 option of isabelle and isatool usedir (currently only observed by
   897 Poly/ML);
   898 
   899 * system: isatool installfonts may handle X-Symbol fonts as well (very
   900 useful for remote X11);
   901 
   902 * system: provide TAGS file for Isabelle sources;
   903 
   904 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   905 order;
   906 
   907 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   908 timing flag supersedes proof_timing and Toplevel.trace;
   909 
   910 * ML: new combinators |>> and |>>> for incremental transformations
   911 with secondary results (e.g. certain theory extensions):
   912 
   913 * ML: PureThy.add_defs gets additional argument to indicate potential
   914 overloading (usually false);
   915 
   916 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   917 results;
   918 
   919 
   920 
   921 New in Isabelle99 (October 1999)
   922 --------------------------------
   923 
   924 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   925 
   926 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   927 are no longer simplified.  (This allows the simplifier to unfold recursive
   928 functional programs.)  To restore the old behaviour, declare
   929 
   930     Delcongs [if_weak_cong];
   931 
   932 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   933 complement;
   934 
   935 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   936 
   937 * HOL/datatype: mutual_induct_tac no longer exists --
   938   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   939 
   940 * HOL/typedef: fixed type inference for representing set; type
   941 arguments now have to occur explicitly on the rhs as type constraints;
   942 
   943 * ZF: The con_defs part of an inductive definition may no longer refer
   944 to constants declared in the same theory;
   945 
   946 * HOL, ZF: the function mk_cases, generated by the inductive
   947 definition package, has lost an argument.  To simplify its result, it
   948 uses the default simpset instead of a supplied list of theorems.
   949 
   950 * HOL/List: the constructors of type list are now Nil and Cons;
   951 
   952 * Simplifier: the type of the infix ML functions
   953         setSSolver addSSolver setSolver addSolver
   954 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   955 for packaging solvers. A solver is created via
   956         mk_solver: string -> (thm list -> int -> tactic) -> solver
   957 where the string argument is only a comment.
   958 
   959 
   960 *** Proof tools ***
   961 
   962 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   963 decision procedure for linear arithmetic. Currently it is used for
   964 types `nat', `int', and `real' in HOL (see below); it can, should and
   965 will be instantiated for other types and logics as well.
   966 
   967 * The simplifier now accepts rewrite rules with flexible heads, eg
   968      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   969   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   970   matching.
   971 
   972 
   973 *** General ***
   974 
   975 * New Isabelle/Isar subsystem provides an alternative to traditional
   976 tactical theorem proving; together with the ProofGeneral/isar user
   977 interface it offers an interactive environment for developing human
   978 readable proof documents (Isar == Intelligible semi-automated
   979 reasoning); for further information see isatool doc isar-ref,
   980 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   981 
   982 * improved and simplified presentation of theories: better HTML markup
   983 (including colors), graph views in several sizes; isatool usedir now
   984 provides a proper interface for user theories (via -P option); actual
   985 document preparation based on (PDF)LaTeX is available as well (for
   986 new-style theories only); see isatool doc system for more information;
   987 
   988 * native support for Proof General, both for classic Isabelle and
   989 Isabelle/Isar;
   990 
   991 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   992 using the graph browser tool;
   993 
   994 * Isabelle manuals now also available as PDF;
   995 
   996 * theory loader rewritten from scratch (may not be fully
   997 bug-compatible); old loadpath variable has been replaced by show_path,
   998 add_path, del_path, reset_path functions; new operations such as
   999 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1000 isatool doc ref);
  1001 
  1002 * improved isatool install: option -k creates KDE application icon,
  1003 option -p DIR installs standalone binaries;
  1004 
  1005 * added ML_PLATFORM setting (useful for cross-platform installations);
  1006 more robust handling of platform specific ML images for SML/NJ;
  1007 
  1008 * the settings environment is now statically scoped, i.e. it is never
  1009 created again in sub-processes invoked from isabelle, isatool, or
  1010 Isabelle;
  1011 
  1012 * path element specification '~~' refers to '$ISABELLE_HOME';
  1013 
  1014 * in locales, the "assumes" and "defines" parts may be omitted if
  1015 empty;
  1016 
  1017 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1018 long arrows);
  1019 
  1020 * new print_mode "HTML";
  1021 
  1022 * new flag show_tags controls display of tags of theorems (which are
  1023 basically just comments that may be attached by some tools);
  1024 
  1025 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1026 mode and goal output format:
  1027 
  1028 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1029 244c244
  1030 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1031 ---
  1032 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1033 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1034 181c181
  1035 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1036 ---
  1037 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1038 
  1039 * function bind_thms stores lists of theorems (cf. bind_thm);
  1040 
  1041 * new shorthand tactics ftac, eatac, datac, fatac;
  1042 
  1043 * qed (and friends) now accept "" as result name; in that case the
  1044 theorem is not stored, but proper checks and presentation of the
  1045 result still apply;
  1046 
  1047 * theorem database now also indexes constants "Trueprop", "all",
  1048 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1049 
  1050 
  1051 *** HOL ***
  1052 
  1053 ** HOL arithmetic **
  1054 
  1055 * There are now decision procedures for linear arithmetic over nat and
  1056 int:
  1057 
  1058 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1059 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1060 are treated as atomic; subformulae not involving type `nat' or `int'
  1061 are ignored; quantified subformulae are ignored unless they are
  1062 positive universal or negative existential. The tactic has to be
  1063 invoked by hand and can be a little bit slow. In particular, the
  1064 running time is exponential in the number of occurrences of `min' and
  1065 `max', and `-' on `nat'.
  1066 
  1067 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1068 (negated) (in)equalities among the premises and the conclusion into
  1069 account (i.e. no compound formulae) and does not know about `min' and
  1070 `max', and `-' on `nat'. It is fast and is used automatically by the
  1071 simplifier.
  1072 
  1073 NB: At the moment, these decision procedures do not cope with mixed
  1074 nat/int formulae where the two parts interact, such as `m < n ==>
  1075 int(m) < int(n)'.
  1076 
  1077 * HOL/Numeral provides a generic theory of numerals (encoded
  1078 efficiently as bit strings); setup for types nat/int/real is in place;
  1079 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1080 int, existing theories and proof scripts may require a few additional
  1081 type constraints;
  1082 
  1083 * integer division and remainder can now be performed on constant
  1084 arguments;
  1085 
  1086 * many properties of integer multiplication, division and remainder
  1087 are now available;
  1088 
  1089 * An interface to the Stanford Validity Checker (SVC) is available through the
  1090 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1091 are proved automatically.  SVC must be installed separately, and its results
  1092 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1093 invocation of the underlying oracle).  For SVC see
  1094   http://verify.stanford.edu/SVC
  1095 
  1096 * IsaMakefile: the HOL-Real target now builds an actual image;
  1097 
  1098 
  1099 ** HOL misc **
  1100 
  1101 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1102 (in Isabelle/Isar) -- by Gertrud Bauer;
  1103 
  1104 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1105 analysis for assembly languages with subtypes;
  1106 
  1107 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1108 -- avoids syntactic ambiguities and treats state, transition, and
  1109 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1110 changed syntax and (many) tactics;
  1111 
  1112 * HOL/inductive: Now also handles more general introduction rules such
  1113   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1114   theorems are now maintained within the theory (maintained via the
  1115   "mono" attribute);
  1116 
  1117 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1118   (using function types) such as
  1119 
  1120   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1121 
  1122 * HOL/record: record_simproc (part of the default simpset) takes care
  1123 of selectors applied to updated records; record_split_tac is no longer
  1124 part of the default claset; update_defs may now be removed from the
  1125 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1126 
  1127   claset_ref () := claset() addSWrapper record_split_wrapper;
  1128   Delsimprocs [record_simproc]
  1129 
  1130 * HOL/typedef: fixed type inference for representing set; type
  1131 arguments now have to occur explicitly on the rhs as type constraints;
  1132 
  1133 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1134 names rather than an ML expression;
  1135 
  1136 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1137 supplied later.  Program schemes can be defined, such as
  1138     "While B C s = (if B s then While B C (C s) else s)"
  1139 where the well-founded relation can be chosen after B and C have been given.
  1140 
  1141 * HOL/List: the constructors of type list are now Nil and Cons;
  1142 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1143 course, ML tools referring to List.list.op # etc. have to be adapted;
  1144 
  1145 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1146 disabled by default; run isabelle with option -m HOL to get back to
  1147 the original Gordon/HOL-style output;
  1148 
  1149 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1150 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1151 
  1152 * HOL basic syntax simplified (more orthogonal): all variants of
  1153 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1154 Eps operator is provided as well: "SOME x. P[x]";
  1155 
  1156 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1157 
  1158 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1159 thus available for user theories;
  1160 
  1161 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1162 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1163 time;
  1164 
  1165 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1166 several times and then mp;
  1167 
  1168 
  1169 *** LK ***
  1170 
  1171 * the notation <<...>> is now available as a notation for sequences of
  1172 formulas;
  1173 
  1174 * the simplifier is now installed
  1175 
  1176 * the axiom system has been generalized (thanks to Soren Heilmann)
  1177 
  1178 * the classical reasoner now has a default rule database
  1179 
  1180 
  1181 *** ZF ***
  1182 
  1183 * new primrec section allows primitive recursive functions to be given
  1184 directly (as in HOL) over datatypes and the natural numbers;
  1185 
  1186 * new tactics induct_tac and exhaust_tac for induction (or case
  1187 analysis) over datatypes and the natural numbers;
  1188 
  1189 * the datatype declaration of type T now defines the recursor T_rec;
  1190 
  1191 * simplification automatically does freeness reasoning for datatype
  1192 constructors;
  1193 
  1194 * automatic type-inference, with AddTCs command to insert new
  1195 type-checking rules;
  1196 
  1197 * datatype introduction rules are now added as Safe Introduction rules
  1198 to the claset;
  1199 
  1200 * the syntax "if P then x else y" is now available in addition to
  1201 if(P,x,y);
  1202 
  1203 
  1204 *** Internal programming interfaces ***
  1205 
  1206 * tuned simplifier trace output; new flag debug_simp;
  1207 
  1208 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1209 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1210 
  1211 * AxClass.axclass_tac lost the theory argument;
  1212 
  1213 * tuned current_goals_markers semantics: begin / end goal avoids
  1214 printing empty lines;
  1215 
  1216 * removed prs and prs_fn hook, which was broken because it did not
  1217 include \n in its semantics, forcing writeln to add one
  1218 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1219 string -> unit if you really want to output text without newline;
  1220 
  1221 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1222 plain output, interface builders may have to enable 'isabelle_font'
  1223 mode to get Isabelle font glyphs as before;
  1224 
  1225 * refined token_translation interface; INCOMPATIBILITY: output length
  1226 now of type real instead of int;
  1227 
  1228 * theory loader actions may be traced via new ThyInfo.add_hook
  1229 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1230 your own database of information attached to *whole* theories -- as
  1231 opposed to intra-theory data slots offered via TheoryDataFun;
  1232 
  1233 * proper handling of dangling sort hypotheses (at last!);
  1234 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1235 extra sort hypotheses that can be witnessed from the type signature;
  1236 the force_strip_shyps flag is gone, any remaining shyps are simply
  1237 left in the theorem (with a warning issued by strip_shyps_warning);
  1238 
  1239 
  1240 
  1241 New in Isabelle98-1 (October 1998)
  1242 ----------------------------------
  1243 
  1244 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1245 
  1246 * several changes of automated proof tools;
  1247 
  1248 * HOL: major changes to the inductive and datatype packages, including
  1249 some minor incompatibilities of theory syntax;
  1250 
  1251 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1252 called `inj_on';
  1253 
  1254 * HOL: removed duplicate thms in Arith:
  1255   less_imp_add_less  should be replaced by  trans_less_add1
  1256   le_imp_add_le      should be replaced by  trans_le_add1
  1257 
  1258 * HOL: unary minus is now overloaded (new type constraints may be
  1259 required);
  1260 
  1261 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1262 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1263 now taken as an integer constant.
  1264 
  1265 * Pure: ML function 'theory_of' renamed to 'theory';
  1266 
  1267 
  1268 *** Proof tools ***
  1269 
  1270 * Simplifier:
  1271   1. Asm_full_simp_tac is now more aggressive.
  1272      1. It will sometimes reorient premises if that increases their power to
  1273         simplify.
  1274      2. It does no longer proceed strictly from left to right but may also
  1275         rotate premises to achieve further simplification.
  1276      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1277      old Asm_full_simp_tac in that it does not rotate premises.
  1278   2. The simplifier now knows a little bit about nat-arithmetic.
  1279 
  1280 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1281 allows for selected deletion of wrappers, by introduction of names for
  1282 wrapper functionals.  This implies that addbefore, addSbefore,
  1283 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1284 and that adding two tactics with the same name overwrites the first
  1285 one (emitting a warning).
  1286   type wrapper = (int -> tactic) -> (int -> tactic)
  1287   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1288   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1289   delWrapper, delSWrapper: claset *  string            -> claset
  1290   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1291 
  1292 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1293 semantics; addbefore now affects only the unsafe part of step_tac
  1294 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1295 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1296 by Force_tac;
  1297 
  1298 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1299 compWrapper; added safe wrapper (and access functions for it);
  1300 
  1301 * HOL/split_all_tac is now much faster and fails if there is nothing
  1302 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1303 and the names of the automatically generated variables have changed.
  1304 split_all_tac has moved within claset() from unsafe wrappers to safe
  1305 wrappers, which means that !!-bound variables are split much more
  1306 aggressively, and safe_tac and clarify_tac now split such variables.
  1307 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1308 Note: the same holds for record_split_tac, which does the job of
  1309 split_all_tac for record fields.
  1310 
  1311 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1312 permanently to the default simpset using Addsplits just like
  1313 Addsimps. They can be removed via Delsplits just like
  1314 Delsimps. Lower-case versions are also available.
  1315 
  1316 * HOL/Simplifier: The rule split_if is now part of the default
  1317 simpset. This means that the simplifier will eliminate all occurrences
  1318 of if-then-else in the conclusion of a goal. To prevent this, you can
  1319 either remove split_if completely from the default simpset by
  1320 `Delsplits [split_if]' or remove it in a specific call of the
  1321 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1322 other case splitting rules to/from the default simpset: every datatype
  1323 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1324 t is the name of the datatype).
  1325 
  1326 * Classical reasoner / Simplifier combination: new force_tac (and
  1327 derivatives Force_tac, force) combines rewriting and classical
  1328 reasoning (and whatever other tools) similarly to auto_tac, but is
  1329 aimed to solve the given subgoal completely.
  1330 
  1331 
  1332 *** General ***
  1333 
  1334 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1335 and `goalw': the theory is no longer needed as an explicit argument -
  1336 the current theory context is used; assumptions are no longer returned
  1337 at the ML-level unless one of them starts with ==> or !!; it is
  1338 recommended to convert to these new commands using isatool fixgoal
  1339 (backup your sources first!);
  1340 
  1341 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1342 the current theory context, and 'theory' to lookup stored theories;
  1343 
  1344 * new theory section 'locale' for declaring constants, assumptions and
  1345 definitions that have local scope;
  1346 
  1347 * new theory section 'nonterminals' for purely syntactic types;
  1348 
  1349 * new theory section 'setup' for generic ML setup functions
  1350 (e.g. package initialization);
  1351 
  1352 * the distribution now includes Isabelle icons: see
  1353 lib/logo/isabelle-{small,tiny}.xpm;
  1354 
  1355 * isatool install - install binaries with absolute references to
  1356 ISABELLE_HOME/bin;
  1357 
  1358 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1359 
  1360 * print mode 'emacs' reserved for Isamode;
  1361 
  1362 * support multiple print (ast) translations per constant name;
  1363 
  1364 * theorems involving oracles are now printed with a suffixed [!];
  1365 
  1366 
  1367 *** HOL ***
  1368 
  1369 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1370 
  1371 * HOL/inductive package reorganized and improved: now supports mutual
  1372 definitions such as
  1373 
  1374   inductive EVEN ODD
  1375     intrs
  1376       null "0 : EVEN"
  1377       oddI "n : EVEN ==> Suc n : ODD"
  1378       evenI "n : ODD ==> Suc n : EVEN"
  1379 
  1380 new theorem list "elims" contains an elimination rule for each of the
  1381 recursive sets; inductive definitions now handle disjunctive premises
  1382 correctly (also ZF);
  1383 
  1384 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1385 "mutual_induct" no longer exists - the induction rule is always
  1386 contained in "induct";
  1387 
  1388 
  1389 * HOL/datatype package re-implemented and greatly improved: now
  1390 supports mutually recursive datatypes such as
  1391 
  1392   datatype
  1393     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1394             | SUM ('a aexp) ('a aexp)
  1395             | DIFF ('a aexp) ('a aexp)
  1396             | NUM 'a
  1397   and
  1398     'a bexp = LESS ('a aexp) ('a aexp)
  1399             | AND ('a bexp) ('a bexp)
  1400             | OR ('a bexp) ('a bexp)
  1401 
  1402 as well as indirectly recursive datatypes such as
  1403 
  1404   datatype
  1405     ('a, 'b) term = Var 'a
  1406                   | App 'b ((('a, 'b) term) list)
  1407 
  1408 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1409 induction on mutually / indirectly recursive datatypes.
  1410 
  1411 Primrec equations are now stored in theory and can be accessed via
  1412 <function_name>.simps.
  1413 
  1414 INCOMPATIBILITIES:
  1415 
  1416   - Theories using datatypes must now have theory Datatype as an
  1417     ancestor.
  1418   - The specific <typename>.induct_tac no longer exists - use the
  1419     generic induct_tac instead.
  1420   - natE has been renamed to nat.exhaust - use exhaust_tac
  1421     instead of res_inst_tac ... natE. Note that the variable
  1422     names in nat.exhaust differ from the names in natE, this
  1423     may cause some "fragile" proofs to fail.
  1424   - The theorems split_<typename>_case and split_<typename>_case_asm
  1425     have been renamed to <typename>.split and <typename>.split_asm.
  1426   - Since default sorts of type variables are now handled correctly,
  1427     some datatype definitions may have to be annotated with explicit
  1428     sort constraints.
  1429   - Primrec definitions no longer require function name and type
  1430     of recursive argument.
  1431 
  1432 Consider using isatool fixdatatype to adapt your theories and proof
  1433 scripts to the new package (backup your sources first!).
  1434 
  1435 
  1436 * HOL/record package: considerably improved implementation; now
  1437 includes concrete syntax for record types, terms, updates; theorems
  1438 for surjective pairing and splitting !!-bound record variables; proof
  1439 support is as follows:
  1440 
  1441   1) standard conversions (selectors or updates applied to record
  1442 constructor terms) are part of the standard simpset;
  1443 
  1444   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1445 made part of standard simpset and claset via addIffs;
  1446 
  1447   3) a tactic for record field splitting (record_split_tac) is part of
  1448 the standard claset (addSWrapper);
  1449 
  1450 To get a better idea about these rules you may retrieve them via
  1451 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1452 the name of your record type.
  1453 
  1454 The split tactic 3) conceptually simplifies by the following rule:
  1455 
  1456   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1457 
  1458 Thus any record variable that is bound by meta-all will automatically
  1459 blow up into some record constructor term, consequently the
  1460 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1461 solve record problems automatically.
  1462 
  1463 
  1464 * reorganized the main HOL image: HOL/Integ and String loaded by
  1465 default; theory Main includes everything;
  1466 
  1467 * automatic simplification of integer sums and comparisons, using cancellation;
  1468 
  1469 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1470 
  1471 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1472 
  1473 * many new identities for unions, intersections, set difference, etc.;
  1474 
  1475 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1476 called split_if, split_split, split_sum_case and split_nat_case (to go
  1477 with add/delsplits);
  1478 
  1479 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1480 (?x::unit) = (); this is made part of the default simpset, which COULD
  1481 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1482 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1483 unit_abs_eta_conv is added in order to counter the effect of
  1484 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1485 %u.f();
  1486 
  1487 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1488 makes more sense);
  1489 
  1490 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1491   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1492   disjointness reasoning but breaking a few old proofs.
  1493 
  1494 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1495 to 'converse' from 'inverse' (for compatibility with ZF and some
  1496 literature);
  1497 
  1498 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1499 the well-founded relation;
  1500 
  1501 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1502     Compl A.  The "Compl" syntax remains available as input syntax for this
  1503     release ONLY.
  1504 
  1505 * HOL/Update: new theory of function updates:
  1506     f(a:=b) == %x. if x=a then b else f x
  1507 may also be iterated as in f(a:=b,c:=d,...);
  1508 
  1509 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1510 
  1511 * HOL/List:
  1512   - new function list_update written xs[i:=v] that updates the i-th
  1513     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1514   - new function `upt' written [i..j(] which generates the list
  1515     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1516     bound write [i..j], which is a shorthand for [i..j+1(].
  1517   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1518 
  1519 * HOL/Arith:
  1520   - removed 'pred' (predecessor) function;
  1521   - generalized some theorems about n-1;
  1522   - many new laws about "div" and "mod";
  1523   - new laws about greatest common divisors (see theory ex/Primes);
  1524 
  1525 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1526 instead of "inverse";
  1527 
  1528 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1529   of the multiset ordering;
  1530 
  1531 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1532   (not included by default);
  1533 
  1534 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1535 
  1536 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1537   programs, i.e. different program variables may have different types.
  1538 
  1539 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1540   [previously, this check worked only if the rewrite rule was unconditional]
  1541   Now rew can involve either definitions or equalities (either == or =).
  1542 
  1543 
  1544 *** ZF ***
  1545 
  1546 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1547   only the theorems proved on ZF.ML;
  1548 
  1549 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1550   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1551   disjointness reasoning but breaking a few old proofs.
  1552 
  1553 * ZF/Update: new theory of function updates
  1554     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1555   may also be iterated as in f(a:=b,c:=d,...);
  1556 
  1557 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1558 
  1559 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1560   [previously, this check worked only if the rewrite rule was unconditional]
  1561   Now rew can involve either definitions or equalities (either == or =).
  1562 
  1563 * case_tac provided for compatibility with HOL
  1564     (like the old excluded_middle_tac, but with subgoals swapped)
  1565 
  1566 
  1567 *** Internal programming interfaces ***
  1568 
  1569 * Pure: several new basic modules made available for general use, see
  1570 also src/Pure/README;
  1571 
  1572 * improved the theory data mechanism to support encapsulation (data
  1573 kind name replaced by private Object.kind, acting as authorization
  1574 key); new type-safe user interface via functor TheoryDataFun; generic
  1575 print_data function becomes basically useless;
  1576 
  1577 * removed global_names compatibility flag -- all theory declarations
  1578 are qualified by default;
  1579 
  1580 * module Pure/Syntax now offers quote / antiquote translation
  1581 functions (useful for Hoare logic etc. with implicit dependencies);
  1582 see HOL/ex/Antiquote for an example use;
  1583 
  1584 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1585 cterm -> thm;
  1586 
  1587 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1588 subgoal;
  1589 
  1590 * Display.print_goals function moved to Locale.print_goals;
  1591 
  1592 * standard print function for goals supports current_goals_markers
  1593 variable for marking begin of proof, end of proof, start of goal; the
  1594 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1595 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1596 for example;
  1597 
  1598 
  1599 
  1600 New in Isabelle98 (January 1998)
  1601 --------------------------------
  1602 
  1603 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1604 
  1605 * changed lexical syntax of terms / types: dots made part of long
  1606 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1607 
  1608 * simpset (and claset) reference variable replaced by functions
  1609 simpset / simpset_ref;
  1610 
  1611 * no longer supports theory aliases (via merge) and non-trivial
  1612 implicit merge of thms' signatures;
  1613 
  1614 * most internal names of constants changed due to qualified names;
  1615 
  1616 * changed Pure/Sequence interface (see Pure/seq.ML);
  1617 
  1618 
  1619 *** General Changes ***
  1620 
  1621 * hierachically structured name spaces (for consts, types, axms, thms
  1622 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1623 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1624 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1625 long_names for fully qualified output names; NOTE: ML programs
  1626 (special tactics, packages etc.) referring to internal names may have
  1627 to be adapted to cope with fully qualified names; in case of severe
  1628 backward campatibility problems try setting 'global_names' at compile
  1629 time to have enrything declared within a flat name space; one may also
  1630 fine tune name declarations in theories via the 'global' and 'local'
  1631 section;
  1632 
  1633 * reimplemented the implicit simpset and claset using the new anytype
  1634 data filed in signatures; references simpset:simpset ref etc. are
  1635 replaced by functions simpset:unit->simpset and
  1636 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1637 to patch your ML files accordingly;
  1638 
  1639 * HTML output now includes theory graph data for display with Java
  1640 applet or isatool browser; data generated automatically via isatool
  1641 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1642 
  1643 * defs may now be conditional; improved rewrite_goals_tac to handle
  1644 conditional equations;
  1645 
  1646 * defs now admits additional type arguments, using TYPE('a) syntax;
  1647 
  1648 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1649 creates a new theory node; implicit merge of thms' signatures is
  1650 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1651 transfer:theory->thm->thm in (rare) cases;
  1652 
  1653 * improved handling of draft signatures / theories; draft thms (and
  1654 ctyps, cterms) are automatically promoted to real ones;
  1655 
  1656 * slightly changed interfaces for oracles: admit many per theory, named
  1657 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1658 
  1659 * print_goals: optional output of const types (set show_consts and
  1660 show_types);
  1661 
  1662 * improved output of warnings (###) and errors (***);
  1663 
  1664 * subgoal_tac displays a warning if the new subgoal has type variables;
  1665 
  1666 * removed old README and Makefiles;
  1667 
  1668 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1669 
  1670 * removed obsolete init_pps and init_database;
  1671 
  1672 * deleted the obsolete tactical STATE, which was declared by
  1673     fun STATE tacfun st = tacfun st st;
  1674 
  1675 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1676 (which abbreviates $HOME);
  1677 
  1678 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1679 use isatool fixseq to adapt your ML programs (this works for fully
  1680 qualified references to the Sequence structure only!);
  1681 
  1682 * use_thy no longer requires writable current directory; it always
  1683 reloads .ML *and* .thy file, if either one is out of date;
  1684 
  1685 
  1686 *** Classical Reasoner ***
  1687 
  1688 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1689 tactics that use classical reasoning to simplify a subgoal without
  1690 splitting it into several subgoals;
  1691 
  1692 * Safe_tac: like safe_tac but uses the default claset;
  1693 
  1694 
  1695 *** Simplifier ***
  1696 
  1697 * added simplification meta rules:
  1698     (asm_)(full_)simplify: simpset -> thm -> thm;
  1699 
  1700 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1701 logics (again);
  1702 
  1703 * added prems argument to simplification procedures;
  1704 
  1705 * HOL, FOL, ZF: added infix function `addsplits':
  1706   instead of `<simpset> setloop (split_tac <thms>)'
  1707   you can simply write `<simpset> addsplits <thms>'
  1708 
  1709 
  1710 *** Syntax ***
  1711 
  1712 * TYPE('a) syntax for type reflection terms;
  1713 
  1714 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1715 
  1716 * pretty printer: changed order of mixfix annotation preference (again!);
  1717 
  1718 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1719 
  1720 
  1721 *** HOL ***
  1722 
  1723 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1724   with `addloop' of the simplifier to faciliate case splitting in premises.
  1725 
  1726 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1727 
  1728 * HOL/Auth: new protocol proofs including some for the Internet
  1729   protocol TLS;
  1730 
  1731 * HOL/Map: new theory of `maps' a la VDM;
  1732 
  1733 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1734 cancelling out common nat summands from =, <, <= (in)equalities, or
  1735 differences; simplification procedures nat_cancel_factor for
  1736 cancelling common factor from =, <, <= (in)equalities over natural
  1737 sums; nat_cancel contains both kinds of procedures, it is installed by
  1738 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1739 
  1740 * HOL/simplifier: terms of the form
  1741   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1742   are rewritten to
  1743   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1744   and those of the form
  1745   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1746   are rewritten to
  1747   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1748 
  1749 * HOL/datatype
  1750   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1751 
  1752   P(t_case f1 ... fn x) =
  1753      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1754         ...
  1755        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1756      )
  1757 
  1758   and a theorem `split_t_case_asm' of the form
  1759 
  1760   P(t_case f1 ... fn x) =
  1761     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1762         ...
  1763        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1764      )
  1765   which can be added to a simpset via `addsplits'. The existing theorems
  1766   expand_list_case and expand_option_case have been renamed to
  1767   split_list_case and split_option_case.
  1768 
  1769 * HOL/Arithmetic:
  1770   - `pred n' is automatically converted to `n-1'.
  1771     Users are strongly encouraged not to use `pred' any longer,
  1772     because it will disappear altogether at some point.
  1773   - Users are strongly encouraged to write "0 < n" rather than
  1774     "n ~= 0". Theorems and proof tools have been modified towards this
  1775     `standard'.
  1776 
  1777 * HOL/Lists:
  1778   the function "set_of_list" has been renamed "set" (and its theorems too);
  1779   the function "nth" now takes its arguments in the reverse order and
  1780   has acquired the infix notation "!" as in "xs!n".
  1781 
  1782 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1783 
  1784 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1785   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1786 
  1787 * HOL/record: extensible records with schematic structural subtyping
  1788 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1789 still lacks various theorems and concrete record syntax;
  1790 
  1791 
  1792 *** HOLCF ***
  1793 
  1794 * removed "axioms" and "generated by" sections;
  1795 
  1796 * replaced "ops" section by extended "consts" section, which is capable of
  1797   handling the continuous function space "->" directly;
  1798 
  1799 * domain package:
  1800   . proves theorems immediately and stores them in the theory,
  1801   . creates hierachical name space,
  1802   . now uses normal mixfix annotations (instead of cinfix...),
  1803   . minor changes to some names and values (for consistency),
  1804   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1805   . separator between mutual domain defs: changed "," to "and",
  1806   . improved handling of sort constraints;  now they have to
  1807     appear on the left-hand side of the equations only;
  1808 
  1809 * fixed LAM <x,y,zs>.b syntax;
  1810 
  1811 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1812 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1813 
  1814 
  1815 *** FOL and ZF ***
  1816 
  1817 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1818   with `addloop' of the simplifier to faciliate case splitting in premises.
  1819 
  1820 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1821 in HOL, they strip ALL and --> from proved theorems;
  1822 
  1823 
  1824 
  1825 New in Isabelle94-8 (May 1997)
  1826 ------------------------------
  1827 
  1828 *** General Changes ***
  1829 
  1830 * new utilities to build / run / maintain Isabelle etc. (in parts
  1831 still somewhat experimental); old Makefiles etc. still functional;
  1832 
  1833 * new 'Isabelle System Manual';
  1834 
  1835 * INSTALL text, together with ./configure and ./build scripts;
  1836 
  1837 * reimplemented type inference for greater efficiency, better error
  1838 messages and clean internal interface;
  1839 
  1840 * prlim command for dealing with lots of subgoals (an easier way of
  1841 setting goals_limit);
  1842 
  1843 
  1844 *** Syntax ***
  1845 
  1846 * supports alternative (named) syntax tables (parser and pretty
  1847 printer); internal interface is provided by add_modesyntax(_i);
  1848 
  1849 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1850 be used in conjunction with the Isabelle symbol font; uses the
  1851 "symbols" syntax table;
  1852 
  1853 * added token_translation interface (may translate name tokens in
  1854 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1855 the current print_mode); IMPORTANT: user print translation functions
  1856 are responsible for marking newly introduced bounds
  1857 (Syntax.mark_boundT);
  1858 
  1859 * token translations for modes "xterm" and "xterm_color" that display
  1860 names in bold, underline etc. or colors (which requires a color
  1861 version of xterm);
  1862 
  1863 * infixes may now be declared with names independent of their syntax;
  1864 
  1865 * added typed_print_translation (like print_translation, but may
  1866 access type of constant);
  1867 
  1868 
  1869 *** Classical Reasoner ***
  1870 
  1871 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1872 some limitations.  Blast_tac...
  1873   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1874   + ignores elimination rules that don't have the correct format
  1875         (the conclusion MUST be a formula variable)
  1876   + ignores types, which can make HOL proofs fail
  1877   + rules must not require higher-order unification, e.g. apply_type in ZF
  1878     [message "Function Var's argument not a bound variable" relates to this]
  1879   + its proof strategy is more general but can actually be slower
  1880 
  1881 * substitution with equality assumptions no longer permutes other
  1882 assumptions;
  1883 
  1884 * minor changes in semantics of addafter (now called addaltern); renamed
  1885 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1886 (and access functions for it);
  1887 
  1888 * improved combination of classical reasoner and simplifier:
  1889   + functions for handling clasimpsets
  1890   + improvement of addss: now the simplifier is called _after_ the
  1891     safe steps.
  1892   + safe variant of addss called addSss: uses safe simplifications
  1893     _during_ the safe steps. It is more complete as it allows multiple
  1894     instantiations of unknowns (e.g. with slow_tac).
  1895 
  1896 *** Simplifier ***
  1897 
  1898 * added interface for simplification procedures (functions that
  1899 produce *proven* rewrite rules on the fly, depending on current
  1900 redex);
  1901 
  1902 * ordering on terms as parameter (used for ordered rewriting);
  1903 
  1904 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1905 
  1906 * the solver is now split into a safe and an unsafe part.
  1907 This should be invisible for the normal user, except that the
  1908 functions setsolver and addsolver have been renamed to setSolver and
  1909 addSolver; added safe_asm_full_simp_tac;
  1910 
  1911 
  1912 *** HOL ***
  1913 
  1914 * a generic induction tactic `induct_tac' which works for all datatypes and
  1915 also for type `nat';
  1916 
  1917 * a generic case distinction tactic `exhaust_tac' which works for all
  1918 datatypes and also for type `nat';
  1919 
  1920 * each datatype comes with a function `size';
  1921 
  1922 * patterns in case expressions allow tuple patterns as arguments to
  1923 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1924 
  1925 * primrec now also works with type nat;
  1926 
  1927 * recdef: a new declaration form, allows general recursive functions to be
  1928 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1929 
  1930 * the constant for negation has been renamed from "not" to "Not" to
  1931 harmonize with FOL, ZF, LK, etc.;
  1932 
  1933 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1934 infinite lists;
  1935 
  1936 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1937 
  1938 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1939 problems in commutative rings, using axiomatic type classes for + and *;
  1940 
  1941 * more examples in HOL/MiniML and HOL/Auth;
  1942 
  1943 * more default rewrite rules for quantifiers, union/intersection;
  1944 
  1945 * a new constant `arbitrary == @x.False';
  1946 
  1947 * HOLCF/IOA replaces old HOL/IOA;
  1948 
  1949 * HOLCF changes: derived all rules and arities
  1950   + axiomatic type classes instead of classes
  1951   + typedef instead of faking type definitions
  1952   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1953   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1954   + eliminated the types void, one, tr
  1955   + use unit lift and bool lift (with translations) instead of one and tr
  1956   + eliminated blift from Lift3.thy (use Def instead of blift)
  1957   all eliminated rules are derived as theorems --> no visible changes ;
  1958 
  1959 
  1960 *** ZF ***
  1961 
  1962 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1963 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1964 as ZF_cs addSIs [equalityI];
  1965 
  1966 
  1967 
  1968 New in Isabelle94-7 (November 96)
  1969 ---------------------------------
  1970 
  1971 * allowing negative levels (as offsets) in prlev and choplev;
  1972 
  1973 * super-linear speedup for large simplifications;
  1974 
  1975 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1976 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1977 FAIL); can suppress it using the command Delsimps (ex_simps @
  1978 all_simps); De Morgan laws are also now included, by default;
  1979 
  1980 * improved printing of ==>  :  ~:
  1981 
  1982 * new object-logic "Sequents" adds linear logic, while replacing LK
  1983 and Modal (thanks to Sara Kalvala);
  1984 
  1985 * HOL/Auth: correctness proofs for authentication protocols;
  1986 
  1987 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1988 examples on HOL/Auth);
  1989 
  1990 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1991 the rewriter and classical reasoner simultaneously;
  1992 
  1993 * function uresult no longer returns theorems in "standard" format;
  1994 regain previous version by: val uresult = standard o uresult;
  1995 
  1996 
  1997 
  1998 New in Isabelle94-6
  1999 -------------------
  2000 
  2001 * oracles -- these establish an interface between Isabelle and trusted
  2002 external reasoners, which may deliver results as theorems;
  2003 
  2004 * proof objects (in particular record all uses of oracles);
  2005 
  2006 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2007 
  2008 * "constdefs" section in theory files;
  2009 
  2010 * "primrec" section (HOL) no longer requires names;
  2011 
  2012 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2013 
  2014 
  2015 
  2016 New in Isabelle94-5
  2017 -------------------
  2018 
  2019 * reduced space requirements;
  2020 
  2021 * automatic HTML generation from theories;
  2022 
  2023 * theory files no longer require "..." (quotes) around most types;
  2024 
  2025 * new examples, including two proofs of the Church-Rosser theorem;
  2026 
  2027 * non-curried (1994) version of HOL is no longer distributed;
  2028 
  2029 
  2030 
  2031 New in Isabelle94-4
  2032 -------------------
  2033 
  2034 * greatly reduced space requirements;
  2035 
  2036 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2037 
  2038 * searchable theorem database (see the section "Retrieving theorems" on
  2039 page 8 of the Reference Manual);
  2040 
  2041 * new examples, including Grabczewski's monumental case study of the
  2042 Axiom of Choice;
  2043 
  2044 * The previous version of HOL renamed to Old_HOL;
  2045 
  2046 * The new version of HOL (previously called CHOL) uses a curried syntax
  2047 for functions.  Application looks like f a b instead of f(a,b);
  2048 
  2049 * Mutually recursive inductive definitions finally work in HOL;
  2050 
  2051 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2052 translates to the operator "split";
  2053 
  2054 
  2055 
  2056 New in Isabelle94-3
  2057 -------------------
  2058 
  2059 * new infix operator, addss, allowing the classical reasoner to
  2060 perform simplification at each step of its search.  Example:
  2061         fast_tac (cs addss ss)
  2062 
  2063 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2064 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2065 look like (a,b) instead of <a,b>;
  2066 
  2067 * PLEASE NOTE: CHOL will eventually replace HOL!
  2068 
  2069 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2070 It translates to the operator "split".  A new theory of integers is available;
  2071 
  2072 * In ZF, integer numerals now denote two's-complement binary integers.
  2073 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2074 
  2075 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2076 of the Axiom of Choice;
  2077 
  2078 
  2079 
  2080 New in Isabelle94-2
  2081 -------------------
  2082 
  2083 * Significantly faster resolution;
  2084 
  2085 * the different sections in a .thy file can now be mixed and repeated
  2086 freely;
  2087 
  2088 * Database of theorems for FOL, HOL and ZF.  New
  2089 commands including qed, qed_goal and bind_thm store theorems in the database.
  2090 
  2091 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2092 a given theory (thms_of), or find out what theory a theorem was proved in
  2093 (theory_of_thm);
  2094 
  2095 * Bugs fixed in the inductive definition and datatype packages;
  2096 
  2097 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2098 and HOL_dup_cs obsolete;
  2099 
  2100 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2101 have been removed;
  2102 
  2103 * Simpler definition of function space in ZF;
  2104 
  2105 * new results about cardinal and ordinal arithmetic in ZF;
  2106 
  2107 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2108 types;
  2109 
  2110 
  2111 $Id$