NEWS
author wenzelm
Thu Dec 06 00:45:04 2001 +0100 (2001-12-06)
changeset 12405 9b16f99fd7b9
parent 12364 108cdda23ab3
child 12457 cbfc53e45476
permissions -rw-r--r--
* Pure/obtain: "thesis" now internal (use ?thesis);
* Pure: generic 'sym' / 'symmetric' attributes;
* Provers/classical: 'swapped' attribute;
* HOL: proper rules less_induct and wf_induct_rule;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (?? 2001)
     6 -----------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol;
    31 
    32 
    33 *** Isar ***
    34 
    35 * Pure/Provers: improved proof by cases and induction;
    36   - 'case' command admits impromptu naming of parameters (such as
    37     "case (Suc n)");
    38   - 'induct' method divinates rule instantiation from the inductive
    39     claim; no longer requires excessive ?P bindings for proper
    40     instantiation of cases;
    41   - 'induct' method properly enumerates all possibilities of set/type
    42     rules; as a consequence facts may be also passed through *type*
    43     rules without further ado;
    44   - 'induct' method now derives symbolic cases from the *rulified*
    45     rule (before it used to rulify cases stemming from the internal
    46     atomized version); this means that the context of a non-atomic
    47     statement becomes is included in the hypothesis, avoiding the
    48     slightly cumbersome show "PROP ?case" form;
    49   - 'induct' may now use elim-style induction rules without chaining
    50     facts, using ``missing'' premises from the goal state; this allows
    51     rules stemming from inductive sets to be applied in unstructured
    52     scripts, while still benefitting from proper handling of non-atomic
    53     statements; NB: major inductive premises need to be put first, all
    54     the rest of the goal is passed through the induction;
    55   - 'induct' proper support for mutual induction involving non-atomic
    56     rule statements (uses the new concept of simultaneous goals, see
    57     below);
    58   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    59   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    60   - moved induct/cases attributes to Pure, methods to Provers;
    61   - generic method setup instantiated for FOL and HOL;
    62 
    63 * Pure: support multiple simultaneous goal statements, for example
    64 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    65 meta-level mechanism, this acts as if several individual goals had
    66 been stated separately; in particular common proof methods need to be
    67 repeated in order to cover all claims; note that a single elimination
    68 step is *not* sufficient to establish the two conjunctions, so this
    69 fails:
    70 
    71   assume "A & B" then have A and B ..   (*".." fails*)
    72 
    73 better use "obtain" in situations as above; alternative refer to
    74 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    75 
    76 * Pure: proper integration with ``locales''; unlike the original
    77 version by Florian Kammüller, Isar locales package high-level proof
    78 contexts rather than raw logical ones (e.g. we admit to include
    79 attributes everywhere); operations on locales include merge and
    80 rename; e.g. see HOL/ex/Locales.thy;
    81 
    82 * Pure: theory goals now support ad-hoc contexts, which are discharged
    83 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    84 coincides with that of a locale body;
    85 
    86 * Pure: renamed "antecedent" case to "rule_context";
    87 
    88 * Pure: added 'corollary' command;
    89 
    90 * Pure: fixed 'token_translation' command;
    91 
    92 * Pure: removed obsolete 'exported' attribute;
    93 
    94 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    95 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    96 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    97 
    98 * Pure: method 'atomize' presents local goal premises as object-level
    99 statements (atomic meta-level propositions); setup controlled via
   100 rewrite rules declarations of 'atomize' attribute; example
   101 application: 'induct' method with proper rule statements in improper
   102 proof *scripts*;
   103 
   104 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   105 now consider the syntactic context of assumptions, giving a better
   106 chance to get type-inference of the arguments right (this is
   107 especially important for locales);
   108 
   109 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   110 mode;
   111 
   112 * Pure/obtain: the formal conclusion "thesis", being marked as
   113 ``internal'', may no longer be reference directly in the text;
   114 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   115 situations;
   116 
   117 * Pure: generic 'sym' attribute which declares a rule both as pure
   118 'elim?' and for the 'symmetric' operation;
   119 
   120 * Pure/Provers/classical: simplified integration with pure rule
   121 attributes and methods; the classical "intro?/elim?/dest?"
   122 declarations coincide with the pure ones; the "rule" method no longer
   123 includes classically swapped intros; "intro" and "elim" methods no
   124 longer pick rules from the context; also got rid of ML declarations
   125 AddXIs/AddXEs/AddXDs; all of this has some potential for
   126 INCOMPATIBILITY;
   127 
   128 * Provers/classical: attribute 'swapped' produces classical inversions
   129 of introduction rules;
   130 
   131 * Provers/simplifier: 'simplified' attribute may refer to explicit
   132 rules instead of full simplifier context; 'iff' attribute handles
   133 conditional rules;
   134 
   135 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   136 
   137 * HOL: 'recdef' now fails on unfinished automated proofs, use
   138 "(permissive)" option to recover old behavior;
   139 
   140 * HOL: 'inductive' no longer features separate (collective) attributes
   141 for 'intros' (was found too confusing);
   142 
   143 * HOL: properly declared induction rules less_induct and
   144 wf_induct_rule;
   145 
   146 * HOLCF: domain package adapted to new-style theories, e.g. see
   147 HOLCF/ex/Dnat.thy;
   148 
   149 * ZF: proper integration of logic-specific tools and packages,
   150 including theory commands '(co)inductive', '(co)datatype',
   151 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   152 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   153 
   154 
   155 
   156 *** HOL ***
   157 
   158 * HOL: moved over to sane numeral syntax; the new policy is as
   159 follows:
   160 
   161   - 0 and 1 are polymorphic constants, which are defined on any
   162   numeric type (nat, int, real etc.);
   163 
   164   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   165   binary representation internally;
   166 
   167   - type nat has special constructor Suc, and generally prefers Suc 0
   168   over 1::nat and Suc (Suc 0) over 2::nat;
   169 
   170 This change may cause significant problems of INCOMPATIBILITY; here
   171 are some hints on converting existing sources:
   172 
   173   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   174   entities, so expressions involving "-" (unary or binary minus) need
   175   to be spaced properly;
   176 
   177   - existing occurrences of "1" may need to be constraint "1::nat" or
   178   even replaced by Suc 0; similar for old "2";
   179 
   180   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   181 
   182   - remove all special provisions on numerals in proofs;
   183 
   184 * HOL: the class of all HOL types is now called "type" rather than
   185 "term"; INCOMPATIBILITY, need to adapt references to this type class
   186 in axclass/classes, instance/arities, and (usually rare) occurrences
   187 in typings (of consts etc.); internally the class is called
   188 "HOL.type", ML programs should refer to HOLogic.typeS;
   189 
   190 * HOL/record package improvements:
   191   - new derived operations "fields" to build a partial record section,
   192     "extend" to promote a fixed record to a record scheme, and
   193     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   194     declared as simp by default;
   195   - removed "make_scheme" operations (use "make" with "extend") --
   196     INCOMPATIBILITY;
   197   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   198   - provides cases/induct rules for use with corresponding Isar
   199     methods (for concrete records, record schemes, concrete more
   200     parts, and schematic more parts -- in that order);
   201   - internal definitions directly based on a light-weight abstract
   202     theory of product types over typedef rather than datatype;
   203 
   204 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   205 
   206 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   207 (beware of argument permutation!);
   208 
   209 * HOL: linorder_less_split superseded by linorder_cases;
   210 
   211 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   212 to peripheral theory "Hilbert_Choice";
   213 
   214 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   215 in this (rare) case use:
   216 
   217   delSWrapper "split_all_tac"
   218   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   219 
   220 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   221 MAY FAIL;
   222 
   223 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   224 Isabelle's type classes, ^ on functions and relations has too general
   225 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   226 necessary to attach explicit type constraints;
   227 
   228 * HOL: syntax translations now work properly with numerals and records
   229 expressions;
   230 
   231 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   232 Florian Kammüller;
   233 
   234 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   235 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   236 renamed "Product_Type.unit";
   237 
   238 
   239 *** HOLCF ***
   240 
   241 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
   242 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   243 lift.induct_tac, always use UU instead of Undef;
   244 
   245 
   246 *** ZF ***
   247 
   248 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   249 typeless version of the formalism;
   250 
   251 * ZF/Induct: new directory for examples of inductive definitions,
   252 including theory Multiset for multiset orderings;
   253 
   254 * ZF: the integer library now covers quotients and remainders, with
   255 many laws relating division to addition, multiplication, etc.;
   256 
   257 
   258 *** General ***
   259 
   260 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   261 variable proof controls level of detail: 0 = no proofs (only oracle
   262 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   263 also ref manual for further ML interfaces;
   264 
   265 * Pure/axclass: removed obsolete ML interface
   266 goal_subclass/goal_arity;
   267 
   268 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   269 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   270 separate tokens, so expressions involving minus need to be spaced
   271 properly;
   272 
   273 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   274 rather than "infixl" or "infixr";
   275 
   276 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   277 sort constraint specifications in type inference; e.g. "x::_::foo"
   278 ensures that the type of "x" is of sort "foo" (but not necessarily a
   279 type variable);
   280 
   281 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   282 control output of nested => (types); the default behavior is
   283 "type_brackets";
   284 
   285 * Pure/syntax: builtin parse translation for "_constify" turns valued
   286 tokens into AST constants;
   287 
   288 * Pure/syntax: prefer later declarations of translations and print
   289 translation functions; potential INCOMPATIBILITY: need to reverse
   290 multiple declarations for same syntax element constant;
   291 
   292 * Provers/classical: renamed addaltern to addafter, addSaltern to
   293 addSafter;
   294 
   295 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   296 as well;
   297 
   298 * system: refrain from any attempt at filtering input streams; no
   299 longer support ``8bit'' encoding of old isabelle font, instead proper
   300 iso-latin characters may now be used;
   301 
   302 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   303 
   304 * system: Proof General keywords specification is now part of the
   305 Isabelle distribution (see etc/isar-keywords.el);
   306 
   307 * system: smart selection of Isabelle process versus Isabelle
   308 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   309 run both "isabelle" and "Isabelle" even if file names are badly
   310 damaged (executable inspects the case of the first letter of its own
   311 name); added separate "isabelle-process" and "isabelle-interface";
   312 
   313 
   314 
   315 New in Isabelle99-2 (February 2001)
   316 -----------------------------------
   317 
   318 *** Overview of INCOMPATIBILITIES ***
   319 
   320 * HOL: please note that theories in the Library and elsewhere often use the
   321 new-style (Isar) format; to refer to their theorems in an ML script you must
   322 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   323 
   324 * HOL: inductive package no longer splits induction rule aggressively,
   325 but only as far as specified by the introductions given; the old
   326 format may be recovered via ML function complete_split_rule or attribute
   327 'split_rule (complete)';
   328 
   329 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   330 gfp_Tarski to gfp_unfold;
   331 
   332 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   333 
   334 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   335 relation); infix "^^" has been renamed "``"; infix "``" has been
   336 renamed "`"; "univalent" has been renamed "single_valued";
   337 
   338 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   339 operation;
   340 
   341 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   342 
   343 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   344 
   345 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   346 consequence, it is no longer monotonic wrt. the local goal context
   347 (which is now passed through the inductive cases);
   348 
   349 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   350 \<gg> to \<ggreater>;
   351 
   352 
   353 *** Document preparation ***
   354 
   355 * \isabellestyle{NAME} selects version of Isabelle output (currently
   356 available: are "it" for near math-mode best-style output, "sl" for
   357 slanted text style, and "tt" for plain type-writer; if no
   358 \isabellestyle command is given, output is according to slanted
   359 type-writer);
   360 
   361 * support sub/super scripts (for single symbols only), input syntax is
   362 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   363 
   364 * some more standard symbols; see Appendix A of the system manual for
   365 the complete list of symbols defined in isabellesym.sty;
   366 
   367 * improved isabelle style files; more abstract symbol implementation
   368 (should now use \isamath{...} and \isatext{...} in custom symbol
   369 definitions);
   370 
   371 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   372 state; Note that presentation of goal states does not conform to
   373 actual human-readable proof documents.  Please do not include goal
   374 states into document output unless you really know what you are doing!
   375 
   376 * proper indentation of antiquoted output with proportional LaTeX
   377 fonts;
   378 
   379 * no_document ML operator temporarily disables LaTeX document
   380 generation;
   381 
   382 * isatool unsymbolize tunes sources for plain ASCII communication;
   383 
   384 
   385 *** Isar ***
   386 
   387 * Pure: Isar now suffers initial goal statements to contain unbound
   388 schematic variables (this does not conform to actual readable proof
   389 documents, due to unpredictable outcome and non-compositional proof
   390 checking); users who know what they are doing may use schematic goals
   391 for Prolog-style synthesis of proven results;
   392 
   393 * Pure: assumption method (an implicit finishing) now handles actual
   394 rules as well;
   395 
   396 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   397 initial goal, declare "that" only as Pure intro (only for single
   398 steps); the "that" rule assumption may now be involved in implicit
   399 finishing, thus ".." becomes a feasible for trivial obtains;
   400 
   401 * Pure: default proof step now includes 'intro_classes'; thus trivial
   402 instance proofs may be performed by "..";
   403 
   404 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   405 statements as well;
   406 
   407 * Pure: more robust selection of calculational rules;
   408 
   409 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   410 rule (as well as the assumption rule);
   411 
   412 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   413 lemmas, using the graph browser tool;
   414 
   415 * Pure: predict failure of "show" in interactive mode;
   416 
   417 * Pure: 'thms_containing' now takes actual terms as arguments;
   418 
   419 * HOL: improved method 'induct' --- now handles non-atomic goals
   420 (potential INCOMPATIBILITY); tuned error handling;
   421 
   422 * HOL: cases and induct rules now provide explicit hints about the
   423 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   424 any remaining facts are inserted into the goal verbatim;
   425 
   426 * HOL: local contexts (aka cases) may now contain term bindings as
   427 well; the 'cases' and 'induct' methods new provide a ?case binding for
   428 the result to be shown in each case;
   429 
   430 * HOL: added 'recdef_tc' command;
   431 
   432 * isatool convert assists in eliminating legacy ML scripts;
   433 
   434 
   435 *** HOL ***
   436 
   437 * HOL/Library: a collection of generic theories to be used together
   438 with main HOL; the theory loader path already includes this directory
   439 by default; the following existing theories have been moved here:
   440 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   441 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   442 
   443 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   444 modelling and verification task performed in Isabelle/HOL +
   445 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   446 
   447 * HOL/Algebra: special summation operator SUM no longer exists, it has
   448 been replaced by setsum; infix 'assoc' now has priority 50 (like
   449 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   450 'domain', this makes the theory consistent with mathematical
   451 literature;
   452 
   453 * HOL basics: added overloaded operations "inverse" and "divide"
   454 (infix "/"), syntax for generic "abs" operation, generic summation
   455 operator \<Sum>;
   456 
   457 * HOL/typedef: simplified package, provide more useful rules (see also
   458 HOL/subset.thy);
   459 
   460 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   461 now expressed as a proper nested rule (old-style tactic scripts may
   462 require atomize_strip_tac to cope with non-atomic premises);
   463 
   464 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   465 to "split_conv" (old name still available for compatibility);
   466 
   467 * HOL: improved concrete syntax for strings (e.g. allows translation
   468 rules with string literals);
   469 
   470 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   471  and Fleuriot's mechanization of analysis, including the transcendental
   472  functions for the reals;
   473 
   474 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   475 
   476 
   477 *** CTT ***
   478 
   479 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   480 "lam" is displayed as TWO lambda-symbols
   481 
   482 * CTT: theory Main now available, containing everything (that is, Bool
   483 and Arith);
   484 
   485 
   486 *** General ***
   487 
   488 * Pure: the Simplifier has been implemented properly as a derived rule
   489 outside of the actual kernel (at last!); the overall performance
   490 penalty in practical applications is about 50%, while reliability of
   491 the Isabelle inference kernel has been greatly improved;
   492 
   493 * print modes "brackets" and "no_brackets" control output of nested =>
   494 (types) and ==> (props); the default behaviour is "brackets";
   495 
   496 * Provers: fast_tac (and friends) now handle actual object-logic rules
   497 as assumptions as well;
   498 
   499 * system: support Poly/ML 4.0;
   500 
   501 * system: isatool install handles KDE version 1 or 2;
   502 
   503 
   504 
   505 New in Isabelle99-1 (October 2000)
   506 ----------------------------------
   507 
   508 *** Overview of INCOMPATIBILITIES ***
   509 
   510 * HOL: simplification of natural numbers is much changed; to partly
   511 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   512 issue the following ML commands:
   513 
   514   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   515   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   516 
   517 * HOL: simplification no longer dives into case-expressions; this is
   518 controlled by "t.weak_case_cong" for each datatype t;
   519 
   520 * HOL: nat_less_induct renamed to less_induct;
   521 
   522 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   523 fixsome to patch .thy and .ML sources automatically;
   524 
   525   select_equality  -> some_equality
   526   select_eq_Ex     -> some_eq_ex
   527   selectI2EX       -> someI2_ex
   528   selectI2         -> someI2
   529   selectI          -> someI
   530   select1_equality -> some1_equality
   531   Eps_sym_eq       -> some_sym_eq_trivial
   532   Eps_eq           -> some_eq_trivial
   533 
   534 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   535 
   536 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   537 instead);
   538 
   539 * HOL: the recursion equations generated by 'recdef' are now called
   540 f.simps instead of f.rules;
   541 
   542 * HOL: qed_spec_mp now also handles bounded ALL as well;
   543 
   544 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   545 sometimes be needed;
   546 
   547 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   548 
   549 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   550 
   551 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   552 product is now "<*>" instead of "Times"; the lexicographic product is
   553 now "<*lex*>" instead of "**";
   554 
   555 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   556 of main HOL, but was unused); better use HOL's datatype package;
   557 
   558 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   559 the old syntax may be recovered as follows:
   560 
   561   syntax (symbols)
   562     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   563       (infixl "\\<oplus>" 100)
   564 
   565 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   566 
   567 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   568 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   569 internally;
   570 
   571 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   572 changed from A/r to A//r;
   573 
   574 * ZF: new treatment of arithmetic (nat & int) may break some old
   575 proofs;
   576 
   577 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   578 rulify -> rule_format, elimify -> elim_format, ...);
   579 
   580 * Isar/Provers: intro/elim/dest attributes changed; renamed
   581 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   582 should have to change intro!! to intro? only); replaced "delrule" by
   583 "rule del";
   584 
   585 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   586 
   587 * Provers: strengthened force_tac by using new first_best_tac;
   588 
   589 * LaTeX document preparation: several changes of isabelle.sty (see
   590 lib/texinputs);
   591 
   592 
   593 *** Document preparation ***
   594 
   595 * formal comments (text blocks etc.) in new-style theories may now
   596 contain antiquotations of thm/prop/term/typ/text to be presented
   597 according to latex print mode; concrete syntax is like this:
   598 @{term[show_types] "f(x) = a + x"};
   599 
   600 * isatool mkdir provides easy setup of Isabelle session directories,
   601 including proper document sources;
   602 
   603 * generated LaTeX sources are now deleted after successful run
   604 (isatool document -c); may retain a copy somewhere else via -D option
   605 of isatool usedir;
   606 
   607 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   608 style files, achieving self-contained LaTeX sources and simplifying
   609 LaTeX debugging;
   610 
   611 * old-style theories now produce (crude) LaTeX output as well;
   612 
   613 * browser info session directories are now self-contained (may be put
   614 on WWW server seperately); improved graphs of nested sessions; removed
   615 graph for 'all sessions';
   616 
   617 * several improvements in isabelle style files; \isabellestyle{it}
   618 produces fake math mode output; \isamarkupheader is now \section by
   619 default; see lib/texinputs/isabelle.sty etc.;
   620 
   621 
   622 *** Isar ***
   623 
   624 * Isar/Pure: local results and corresponding term bindings are now
   625 subject to Hindley-Milner polymorphism (similar to ML); this
   626 accommodates incremental type-inference very nicely;
   627 
   628 * Isar/Pure: new derived language element 'obtain' supports
   629 generalized existence reasoning;
   630 
   631 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   632 support accumulation of results, without applying any rules yet;
   633 useful to collect intermediate results without explicit name
   634 references, and for use with transitivity rules with more than 2
   635 premises;
   636 
   637 * Isar/Pure: scalable support for case-analysis type proofs: new
   638 'case' language element refers to local contexts symbolically, as
   639 produced by certain proof methods; internally, case names are attached
   640 to theorems as "tags";
   641 
   642 * Isar/Pure: theory command 'hide' removes declarations from
   643 class/type/const name spaces;
   644 
   645 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   646 indicate potential overloading;
   647 
   648 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   649 
   650 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   651 "{a,b,c}" instead of {a,b,c};
   652 
   653 * Isar/Pure now provides its own version of intro/elim/dest
   654 attributes; useful for building new logics, but beware of confusion
   655 with the version in Provers/classical;
   656 
   657 * Isar/Pure: the local context of (non-atomic) goals is provided via
   658 case name 'antecedent';
   659 
   660 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   661 to the current context is now done automatically);
   662 
   663 * Isar/Pure: theory command 'method_setup' provides a simple interface
   664 for definining proof methods in ML;
   665 
   666 * Isar/Provers: intro/elim/dest attributes changed; renamed
   667 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   668 most cases, one should have to change intro!! to intro? only);
   669 replaced "delrule" by "rule del";
   670 
   671 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   672 'symmetric' attribute (the latter supercedes [RS sym]);
   673 
   674 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   675 method modifier); 'simp' method: 'only:' modifier removes loopers as
   676 well (including splits);
   677 
   678 * Isar/Provers: Simplifier and Classical methods now support all kind
   679 of modifiers used in the past, including 'cong', 'iff', etc.
   680 
   681 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   682 of Simplifier and Classical reasoner);
   683 
   684 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   685 now support named cases; major packages (inductive, datatype, primrec,
   686 recdef) support case names and properly name parameters;
   687 
   688 * Isar/HOL: new transitivity rules for substitution in inequalities --
   689 monotonicity conditions are extracted to be proven at end of
   690 calculations;
   691 
   692 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   693 method anyway;
   694 
   695 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   696 split_if split_if_asm; datatype package provides theorems foo.splits =
   697 foo.split foo.split_asm for each datatype;
   698 
   699 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   700 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   701 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   702 use "(cases (simplified))" method in proper proof texts);
   703 
   704 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   705 
   706 * Isar: names of theorems etc. may be natural numbers as well;
   707 
   708 * Isar: 'pr' command: optional arguments for goals_limit and
   709 ProofContext.prems_limit; no longer prints theory contexts, but only
   710 proof states;
   711 
   712 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   713 additional print modes to be specified; e.g. "pr(latex)" will print
   714 proof state according to the Isabelle LaTeX style;
   715 
   716 * Isar: improved support for emulating tactic scripts, including proof
   717 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   718 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   719 (for HOL datatypes);
   720 
   721 * Isar: simplified (more robust) goal selection of proof methods: 1st
   722 goal, all goals, or explicit goal specifier (tactic emulation); thus
   723 'proof method scripts' have to be in depth-first order;
   724 
   725 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   726 
   727 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   728 should instead use individual commands for printing items
   729 (print_commands, print_methods etc.);
   730 
   731 * Isar: added 'nothing' --- the empty list of theorems;
   732 
   733 
   734 *** HOL ***
   735 
   736 * HOL/MicroJava: formalization of a fragment of Java, together with a
   737 corresponding virtual machine and a specification of its bytecode
   738 verifier and a lightweight bytecode verifier, including proofs of
   739 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   740 Cornelia Pusch (see also the homepage of project Bali at
   741 http://isabelle.in.tum.de/Bali/);
   742 
   743 * HOL/Algebra: new theory of rings and univariate polynomials, by
   744 Clemens Ballarin;
   745 
   746 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   747 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   748 Rasmussen;
   749 
   750 * HOL/Lattice: fundamental concepts of lattice theory and order
   751 structures, including duals, properties of bounds versus algebraic
   752 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   753 Theorem for complete lattices etc.; may also serve as a demonstration
   754 for abstract algebraic reasoning using axiomatic type classes, and
   755 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   756 
   757 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   758 von Oheimb;
   759 
   760 * HOL/IMPP: extension of IMP with local variables and mutually
   761 recursive procedures, by David von Oheimb;
   762 
   763 * HOL/Lambda: converted into new-style theory and document;
   764 
   765 * HOL/ex/Multiquote: example of multiple nested quotations and
   766 anti-quotations -- basically a generalized version of de-Bruijn
   767 representation; very useful in avoiding lifting of operations;
   768 
   769 * HOL/record: added general record equality rule to simpset; fixed
   770 select-update simplification procedure to handle extended records as
   771 well; admit "r" as field name;
   772 
   773 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   774 other numeric types and also as the identity of groups, rings, etc.;
   775 
   776 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   777 Types nat and int belong to this axclass;
   778 
   779 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   780    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   781    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   782   two terms #m*u and #n*u are replaced by #(m+n)*u
   783     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   784   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   785     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   786 
   787 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   788 powerful prover for predicate logic but knows nothing of clasets; see
   789 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   790 
   791 * HOL: new version of "case_tac" subsumes both boolean case split and
   792 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   793 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   794 
   795 * HOL: simplification no longer dives into case-expressions: only the
   796 selector expression is simplified, but not the remaining arms; to
   797 enable full simplification of case-expressions for datatype t, you may
   798 remove t.weak_case_cong from the simpset, either globally (Delcongs
   799 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   800 
   801 * HOL/recdef: the recursion equations generated by 'recdef' for
   802 function 'f' are now called f.simps instead of f.rules; if all
   803 termination conditions are proved automatically, these simplification
   804 rules are added to the simpset, as in primrec; rules may be named
   805 individually as well, resulting in a separate list of theorems for
   806 each equation;
   807 
   808 * HOL/While is a new theory that provides a while-combinator. It
   809 permits the definition of tail-recursive functions without the
   810 provision of a termination measure. The latter is necessary once the
   811 invariant proof rule for while is applied.
   812 
   813 * HOL: new (overloaded) notation for the set of elements below/above
   814 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   815 
   816 * HOL: theorems impI, allI, ballI bound as "strip";
   817 
   818 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   819 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   820 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   821 
   822 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   823 
   824 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   825 main HOL, but was unused);
   826 
   827 * HOL: fewer consts declared as global (e.g. have to refer to
   828 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   829 
   830 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   831 in case of overlap with user translations (e.g. judgements over
   832 tuples); (note that the underlying logical represenation is still
   833 bogus);
   834 
   835 
   836 *** ZF ***
   837 
   838 * ZF: simplification automatically cancels common terms in arithmetic
   839 expressions over nat and int;
   840 
   841 * ZF: new treatment of nat to minimize type-checking: all operators
   842 coerce their operands to a natural number using the function natify,
   843 making the algebraic laws unconditional;
   844 
   845 * ZF: as above, for int: operators coerce their operands to an integer
   846 using the function intify;
   847 
   848 * ZF: the integer library now contains many of the usual laws for the
   849 orderings, including $<=, and monotonicity laws for $+ and $*;
   850 
   851 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   852 simplification;
   853 
   854 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   855 to the simplifier and classical reasoner simultaneously;
   856 
   857 
   858 *** General ***
   859 
   860 * Provers: blast_tac now handles actual object-logic rules as
   861 assumptions; note that auto_tac uses blast_tac internally as well;
   862 
   863 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   864 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   865 
   866 * Provers: delrules now handles destruct rules as well (no longer need
   867 explicit make_elim);
   868 
   869 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   870   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   871 use instead the strong form,
   872   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   873 in HOL, FOL and ZF the function cla_make_elim will create such rules
   874 from destruct-rules;
   875 
   876 * Provers: Simplifier.easy_setup provides a fast path to basic
   877 Simplifier setup for new object-logics;
   878 
   879 * Pure: AST translation rules no longer require constant head on LHS;
   880 
   881 * Pure: improved name spaces: ambiguous output is qualified; support
   882 for hiding of names;
   883 
   884 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   885 XSYMBOL_HOME; no longer need to do manual configuration in most
   886 situations;
   887 
   888 * system: compression of ML heaps images may now be controlled via -c
   889 option of isabelle and isatool usedir (currently only observed by
   890 Poly/ML);
   891 
   892 * system: isatool installfonts may handle X-Symbol fonts as well (very
   893 useful for remote X11);
   894 
   895 * system: provide TAGS file for Isabelle sources;
   896 
   897 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   898 order;
   899 
   900 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   901 timing flag supersedes proof_timing and Toplevel.trace;
   902 
   903 * ML: new combinators |>> and |>>> for incremental transformations
   904 with secondary results (e.g. certain theory extensions):
   905 
   906 * ML: PureThy.add_defs gets additional argument to indicate potential
   907 overloading (usually false);
   908 
   909 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   910 results;
   911 
   912 
   913 
   914 New in Isabelle99 (October 1999)
   915 --------------------------------
   916 
   917 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   918 
   919 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   920 are no longer simplified.  (This allows the simplifier to unfold recursive
   921 functional programs.)  To restore the old behaviour, declare
   922 
   923     Delcongs [if_weak_cong];
   924 
   925 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   926 complement;
   927 
   928 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   929 
   930 * HOL/datatype: mutual_induct_tac no longer exists --
   931   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   932 
   933 * HOL/typedef: fixed type inference for representing set; type
   934 arguments now have to occur explicitly on the rhs as type constraints;
   935 
   936 * ZF: The con_defs part of an inductive definition may no longer refer
   937 to constants declared in the same theory;
   938 
   939 * HOL, ZF: the function mk_cases, generated by the inductive
   940 definition package, has lost an argument.  To simplify its result, it
   941 uses the default simpset instead of a supplied list of theorems.
   942 
   943 * HOL/List: the constructors of type list are now Nil and Cons;
   944 
   945 * Simplifier: the type of the infix ML functions
   946         setSSolver addSSolver setSolver addSolver
   947 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   948 for packaging solvers. A solver is created via
   949         mk_solver: string -> (thm list -> int -> tactic) -> solver
   950 where the string argument is only a comment.
   951 
   952 
   953 *** Proof tools ***
   954 
   955 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   956 decision procedure for linear arithmetic. Currently it is used for
   957 types `nat', `int', and `real' in HOL (see below); it can, should and
   958 will be instantiated for other types and logics as well.
   959 
   960 * The simplifier now accepts rewrite rules with flexible heads, eg
   961      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   962   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   963   matching.
   964 
   965 
   966 *** General ***
   967 
   968 * New Isabelle/Isar subsystem provides an alternative to traditional
   969 tactical theorem proving; together with the ProofGeneral/isar user
   970 interface it offers an interactive environment for developing human
   971 readable proof documents (Isar == Intelligible semi-automated
   972 reasoning); for further information see isatool doc isar-ref,
   973 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   974 
   975 * improved and simplified presentation of theories: better HTML markup
   976 (including colors), graph views in several sizes; isatool usedir now
   977 provides a proper interface for user theories (via -P option); actual
   978 document preparation based on (PDF)LaTeX is available as well (for
   979 new-style theories only); see isatool doc system for more information;
   980 
   981 * native support for Proof General, both for classic Isabelle and
   982 Isabelle/Isar;
   983 
   984 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   985 using the graph browser tool;
   986 
   987 * Isabelle manuals now also available as PDF;
   988 
   989 * theory loader rewritten from scratch (may not be fully
   990 bug-compatible); old loadpath variable has been replaced by show_path,
   991 add_path, del_path, reset_path functions; new operations such as
   992 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   993 isatool doc ref);
   994 
   995 * improved isatool install: option -k creates KDE application icon,
   996 option -p DIR installs standalone binaries;
   997 
   998 * added ML_PLATFORM setting (useful for cross-platform installations);
   999 more robust handling of platform specific ML images for SML/NJ;
  1000 
  1001 * the settings environment is now statically scoped, i.e. it is never
  1002 created again in sub-processes invoked from isabelle, isatool, or
  1003 Isabelle;
  1004 
  1005 * path element specification '~~' refers to '$ISABELLE_HOME';
  1006 
  1007 * in locales, the "assumes" and "defines" parts may be omitted if
  1008 empty;
  1009 
  1010 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1011 long arrows);
  1012 
  1013 * new print_mode "HTML";
  1014 
  1015 * new flag show_tags controls display of tags of theorems (which are
  1016 basically just comments that may be attached by some tools);
  1017 
  1018 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1019 mode and goal output format:
  1020 
  1021 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1022 244c244
  1023 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1024 ---
  1025 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1026 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1027 181c181
  1028 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1029 ---
  1030 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1031 
  1032 * function bind_thms stores lists of theorems (cf. bind_thm);
  1033 
  1034 * new shorthand tactics ftac, eatac, datac, fatac;
  1035 
  1036 * qed (and friends) now accept "" as result name; in that case the
  1037 theorem is not stored, but proper checks and presentation of the
  1038 result still apply;
  1039 
  1040 * theorem database now also indexes constants "Trueprop", "all",
  1041 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1042 
  1043 
  1044 *** HOL ***
  1045 
  1046 ** HOL arithmetic **
  1047 
  1048 * There are now decision procedures for linear arithmetic over nat and
  1049 int:
  1050 
  1051 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1052 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1053 are treated as atomic; subformulae not involving type `nat' or `int'
  1054 are ignored; quantified subformulae are ignored unless they are
  1055 positive universal or negative existential. The tactic has to be
  1056 invoked by hand and can be a little bit slow. In particular, the
  1057 running time is exponential in the number of occurrences of `min' and
  1058 `max', and `-' on `nat'.
  1059 
  1060 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1061 (negated) (in)equalities among the premises and the conclusion into
  1062 account (i.e. no compound formulae) and does not know about `min' and
  1063 `max', and `-' on `nat'. It is fast and is used automatically by the
  1064 simplifier.
  1065 
  1066 NB: At the moment, these decision procedures do not cope with mixed
  1067 nat/int formulae where the two parts interact, such as `m < n ==>
  1068 int(m) < int(n)'.
  1069 
  1070 * HOL/Numeral provides a generic theory of numerals (encoded
  1071 efficiently as bit strings); setup for types nat/int/real is in place;
  1072 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1073 int, existing theories and proof scripts may require a few additional
  1074 type constraints;
  1075 
  1076 * integer division and remainder can now be performed on constant
  1077 arguments;
  1078 
  1079 * many properties of integer multiplication, division and remainder
  1080 are now available;
  1081 
  1082 * An interface to the Stanford Validity Checker (SVC) is available through the
  1083 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1084 are proved automatically.  SVC must be installed separately, and its results
  1085 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1086 invocation of the underlying oracle).  For SVC see
  1087   http://verify.stanford.edu/SVC
  1088 
  1089 * IsaMakefile: the HOL-Real target now builds an actual image;
  1090 
  1091 
  1092 ** HOL misc **
  1093 
  1094 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1095 (in Isabelle/Isar) -- by Gertrud Bauer;
  1096 
  1097 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1098 analysis for assembly languages with subtypes;
  1099 
  1100 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1101 -- avoids syntactic ambiguities and treats state, transition, and
  1102 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1103 changed syntax and (many) tactics;
  1104 
  1105 * HOL/inductive: Now also handles more general introduction rules such
  1106   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1107   theorems are now maintained within the theory (maintained via the
  1108   "mono" attribute);
  1109 
  1110 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1111   (using function types) such as
  1112 
  1113   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1114 
  1115 * HOL/record: record_simproc (part of the default simpset) takes care
  1116 of selectors applied to updated records; record_split_tac is no longer
  1117 part of the default claset; update_defs may now be removed from the
  1118 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1119 
  1120   claset_ref () := claset() addSWrapper record_split_wrapper;
  1121   Delsimprocs [record_simproc]
  1122 
  1123 * HOL/typedef: fixed type inference for representing set; type
  1124 arguments now have to occur explicitly on the rhs as type constraints;
  1125 
  1126 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1127 names rather than an ML expression;
  1128 
  1129 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1130 supplied later.  Program schemes can be defined, such as
  1131     "While B C s = (if B s then While B C (C s) else s)"
  1132 where the well-founded relation can be chosen after B and C have been given.
  1133 
  1134 * HOL/List: the constructors of type list are now Nil and Cons;
  1135 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1136 course, ML tools referring to List.list.op # etc. have to be adapted;
  1137 
  1138 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1139 disabled by default; run isabelle with option -m HOL to get back to
  1140 the original Gordon/HOL-style output;
  1141 
  1142 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1143 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1144 
  1145 * HOL basic syntax simplified (more orthogonal): all variants of
  1146 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1147 Eps operator is provided as well: "SOME x. P[x]";
  1148 
  1149 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1150 
  1151 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1152 thus available for user theories;
  1153 
  1154 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1155 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1156 time;
  1157 
  1158 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1159 several times and then mp;
  1160 
  1161 
  1162 *** LK ***
  1163 
  1164 * the notation <<...>> is now available as a notation for sequences of
  1165 formulas;
  1166 
  1167 * the simplifier is now installed
  1168 
  1169 * the axiom system has been generalized (thanks to Soren Heilmann)
  1170 
  1171 * the classical reasoner now has a default rule database
  1172 
  1173 
  1174 *** ZF ***
  1175 
  1176 * new primrec section allows primitive recursive functions to be given
  1177 directly (as in HOL) over datatypes and the natural numbers;
  1178 
  1179 * new tactics induct_tac and exhaust_tac for induction (or case
  1180 analysis) over datatypes and the natural numbers;
  1181 
  1182 * the datatype declaration of type T now defines the recursor T_rec;
  1183 
  1184 * simplification automatically does freeness reasoning for datatype
  1185 constructors;
  1186 
  1187 * automatic type-inference, with AddTCs command to insert new
  1188 type-checking rules;
  1189 
  1190 * datatype introduction rules are now added as Safe Introduction rules
  1191 to the claset;
  1192 
  1193 * the syntax "if P then x else y" is now available in addition to
  1194 if(P,x,y);
  1195 
  1196 
  1197 *** Internal programming interfaces ***
  1198 
  1199 * tuned simplifier trace output; new flag debug_simp;
  1200 
  1201 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1202 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1203 
  1204 * AxClass.axclass_tac lost the theory argument;
  1205 
  1206 * tuned current_goals_markers semantics: begin / end goal avoids
  1207 printing empty lines;
  1208 
  1209 * removed prs and prs_fn hook, which was broken because it did not
  1210 include \n in its semantics, forcing writeln to add one
  1211 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1212 string -> unit if you really want to output text without newline;
  1213 
  1214 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1215 plain output, interface builders may have to enable 'isabelle_font'
  1216 mode to get Isabelle font glyphs as before;
  1217 
  1218 * refined token_translation interface; INCOMPATIBILITY: output length
  1219 now of type real instead of int;
  1220 
  1221 * theory loader actions may be traced via new ThyInfo.add_hook
  1222 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1223 your own database of information attached to *whole* theories -- as
  1224 opposed to intra-theory data slots offered via TheoryDataFun;
  1225 
  1226 * proper handling of dangling sort hypotheses (at last!);
  1227 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1228 extra sort hypotheses that can be witnessed from the type signature;
  1229 the force_strip_shyps flag is gone, any remaining shyps are simply
  1230 left in the theorem (with a warning issued by strip_shyps_warning);
  1231 
  1232 
  1233 
  1234 New in Isabelle98-1 (October 1998)
  1235 ----------------------------------
  1236 
  1237 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1238 
  1239 * several changes of automated proof tools;
  1240 
  1241 * HOL: major changes to the inductive and datatype packages, including
  1242 some minor incompatibilities of theory syntax;
  1243 
  1244 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1245 called `inj_on';
  1246 
  1247 * HOL: removed duplicate thms in Arith:
  1248   less_imp_add_less  should be replaced by  trans_less_add1
  1249   le_imp_add_le      should be replaced by  trans_le_add1
  1250 
  1251 * HOL: unary minus is now overloaded (new type constraints may be
  1252 required);
  1253 
  1254 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1255 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1256 now taken as an integer constant.
  1257 
  1258 * Pure: ML function 'theory_of' renamed to 'theory';
  1259 
  1260 
  1261 *** Proof tools ***
  1262 
  1263 * Simplifier:
  1264   1. Asm_full_simp_tac is now more aggressive.
  1265      1. It will sometimes reorient premises if that increases their power to
  1266         simplify.
  1267      2. It does no longer proceed strictly from left to right but may also
  1268         rotate premises to achieve further simplification.
  1269      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1270      old Asm_full_simp_tac in that it does not rotate premises.
  1271   2. The simplifier now knows a little bit about nat-arithmetic.
  1272 
  1273 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1274 allows for selected deletion of wrappers, by introduction of names for
  1275 wrapper functionals.  This implies that addbefore, addSbefore,
  1276 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1277 and that adding two tactics with the same name overwrites the first
  1278 one (emitting a warning).
  1279   type wrapper = (int -> tactic) -> (int -> tactic)
  1280   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1281   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1282   delWrapper, delSWrapper: claset *  string            -> claset
  1283   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1284 
  1285 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1286 semantics; addbefore now affects only the unsafe part of step_tac
  1287 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1288 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1289 by Force_tac;
  1290 
  1291 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1292 compWrapper; added safe wrapper (and access functions for it);
  1293 
  1294 * HOL/split_all_tac is now much faster and fails if there is nothing
  1295 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1296 and the names of the automatically generated variables have changed.
  1297 split_all_tac has moved within claset() from unsafe wrappers to safe
  1298 wrappers, which means that !!-bound variables are split much more
  1299 aggressively, and safe_tac and clarify_tac now split such variables.
  1300 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1301 Note: the same holds for record_split_tac, which does the job of
  1302 split_all_tac for record fields.
  1303 
  1304 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1305 permanently to the default simpset using Addsplits just like
  1306 Addsimps. They can be removed via Delsplits just like
  1307 Delsimps. Lower-case versions are also available.
  1308 
  1309 * HOL/Simplifier: The rule split_if is now part of the default
  1310 simpset. This means that the simplifier will eliminate all occurrences
  1311 of if-then-else in the conclusion of a goal. To prevent this, you can
  1312 either remove split_if completely from the default simpset by
  1313 `Delsplits [split_if]' or remove it in a specific call of the
  1314 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1315 other case splitting rules to/from the default simpset: every datatype
  1316 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1317 t is the name of the datatype).
  1318 
  1319 * Classical reasoner / Simplifier combination: new force_tac (and
  1320 derivatives Force_tac, force) combines rewriting and classical
  1321 reasoning (and whatever other tools) similarly to auto_tac, but is
  1322 aimed to solve the given subgoal completely.
  1323 
  1324 
  1325 *** General ***
  1326 
  1327 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1328 and `goalw': the theory is no longer needed as an explicit argument -
  1329 the current theory context is used; assumptions are no longer returned
  1330 at the ML-level unless one of them starts with ==> or !!; it is
  1331 recommended to convert to these new commands using isatool fixgoal
  1332 (backup your sources first!);
  1333 
  1334 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1335 the current theory context, and 'theory' to lookup stored theories;
  1336 
  1337 * new theory section 'locale' for declaring constants, assumptions and
  1338 definitions that have local scope;
  1339 
  1340 * new theory section 'nonterminals' for purely syntactic types;
  1341 
  1342 * new theory section 'setup' for generic ML setup functions
  1343 (e.g. package initialization);
  1344 
  1345 * the distribution now includes Isabelle icons: see
  1346 lib/logo/isabelle-{small,tiny}.xpm;
  1347 
  1348 * isatool install - install binaries with absolute references to
  1349 ISABELLE_HOME/bin;
  1350 
  1351 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1352 
  1353 * print mode 'emacs' reserved for Isamode;
  1354 
  1355 * support multiple print (ast) translations per constant name;
  1356 
  1357 * theorems involving oracles are now printed with a suffixed [!];
  1358 
  1359 
  1360 *** HOL ***
  1361 
  1362 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1363 
  1364 * HOL/inductive package reorganized and improved: now supports mutual
  1365 definitions such as
  1366 
  1367   inductive EVEN ODD
  1368     intrs
  1369       null "0 : EVEN"
  1370       oddI "n : EVEN ==> Suc n : ODD"
  1371       evenI "n : ODD ==> Suc n : EVEN"
  1372 
  1373 new theorem list "elims" contains an elimination rule for each of the
  1374 recursive sets; inductive definitions now handle disjunctive premises
  1375 correctly (also ZF);
  1376 
  1377 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1378 "mutual_induct" no longer exists - the induction rule is always
  1379 contained in "induct";
  1380 
  1381 
  1382 * HOL/datatype package re-implemented and greatly improved: now
  1383 supports mutually recursive datatypes such as
  1384 
  1385   datatype
  1386     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1387             | SUM ('a aexp) ('a aexp)
  1388             | DIFF ('a aexp) ('a aexp)
  1389             | NUM 'a
  1390   and
  1391     'a bexp = LESS ('a aexp) ('a aexp)
  1392             | AND ('a bexp) ('a bexp)
  1393             | OR ('a bexp) ('a bexp)
  1394 
  1395 as well as indirectly recursive datatypes such as
  1396 
  1397   datatype
  1398     ('a, 'b) term = Var 'a
  1399                   | App 'b ((('a, 'b) term) list)
  1400 
  1401 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1402 induction on mutually / indirectly recursive datatypes.
  1403 
  1404 Primrec equations are now stored in theory and can be accessed via
  1405 <function_name>.simps.
  1406 
  1407 INCOMPATIBILITIES:
  1408 
  1409   - Theories using datatypes must now have theory Datatype as an
  1410     ancestor.
  1411   - The specific <typename>.induct_tac no longer exists - use the
  1412     generic induct_tac instead.
  1413   - natE has been renamed to nat.exhaust - use exhaust_tac
  1414     instead of res_inst_tac ... natE. Note that the variable
  1415     names in nat.exhaust differ from the names in natE, this
  1416     may cause some "fragile" proofs to fail.
  1417   - The theorems split_<typename>_case and split_<typename>_case_asm
  1418     have been renamed to <typename>.split and <typename>.split_asm.
  1419   - Since default sorts of type variables are now handled correctly,
  1420     some datatype definitions may have to be annotated with explicit
  1421     sort constraints.
  1422   - Primrec definitions no longer require function name and type
  1423     of recursive argument.
  1424 
  1425 Consider using isatool fixdatatype to adapt your theories and proof
  1426 scripts to the new package (backup your sources first!).
  1427 
  1428 
  1429 * HOL/record package: considerably improved implementation; now
  1430 includes concrete syntax for record types, terms, updates; theorems
  1431 for surjective pairing and splitting !!-bound record variables; proof
  1432 support is as follows:
  1433 
  1434   1) standard conversions (selectors or updates applied to record
  1435 constructor terms) are part of the standard simpset;
  1436 
  1437   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1438 made part of standard simpset and claset via addIffs;
  1439 
  1440   3) a tactic for record field splitting (record_split_tac) is part of
  1441 the standard claset (addSWrapper);
  1442 
  1443 To get a better idea about these rules you may retrieve them via
  1444 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1445 the name of your record type.
  1446 
  1447 The split tactic 3) conceptually simplifies by the following rule:
  1448 
  1449   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1450 
  1451 Thus any record variable that is bound by meta-all will automatically
  1452 blow up into some record constructor term, consequently the
  1453 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1454 solve record problems automatically.
  1455 
  1456 
  1457 * reorganized the main HOL image: HOL/Integ and String loaded by
  1458 default; theory Main includes everything;
  1459 
  1460 * automatic simplification of integer sums and comparisons, using cancellation;
  1461 
  1462 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1463 
  1464 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1465 
  1466 * many new identities for unions, intersections, set difference, etc.;
  1467 
  1468 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1469 called split_if, split_split, split_sum_case and split_nat_case (to go
  1470 with add/delsplits);
  1471 
  1472 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1473 (?x::unit) = (); this is made part of the default simpset, which COULD
  1474 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1475 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1476 unit_abs_eta_conv is added in order to counter the effect of
  1477 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1478 %u.f();
  1479 
  1480 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1481 makes more sense);
  1482 
  1483 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1484   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1485   disjointness reasoning but breaking a few old proofs.
  1486 
  1487 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1488 to 'converse' from 'inverse' (for compatibility with ZF and some
  1489 literature);
  1490 
  1491 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1492 the well-founded relation;
  1493 
  1494 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1495     Compl A.  The "Compl" syntax remains available as input syntax for this
  1496     release ONLY.
  1497 
  1498 * HOL/Update: new theory of function updates:
  1499     f(a:=b) == %x. if x=a then b else f x
  1500 may also be iterated as in f(a:=b,c:=d,...);
  1501 
  1502 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1503 
  1504 * HOL/List:
  1505   - new function list_update written xs[i:=v] that updates the i-th
  1506     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1507   - new function `upt' written [i..j(] which generates the list
  1508     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1509     bound write [i..j], which is a shorthand for [i..j+1(].
  1510   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1511 
  1512 * HOL/Arith:
  1513   - removed 'pred' (predecessor) function;
  1514   - generalized some theorems about n-1;
  1515   - many new laws about "div" and "mod";
  1516   - new laws about greatest common divisors (see theory ex/Primes);
  1517 
  1518 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1519 instead of "inverse";
  1520 
  1521 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1522   of the multiset ordering;
  1523 
  1524 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1525   (not included by default);
  1526 
  1527 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1528 
  1529 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1530   programs, i.e. different program variables may have different types.
  1531 
  1532 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1533   [previously, this check worked only if the rewrite rule was unconditional]
  1534   Now rew can involve either definitions or equalities (either == or =).
  1535 
  1536 
  1537 *** ZF ***
  1538 
  1539 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1540   only the theorems proved on ZF.ML;
  1541 
  1542 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1543   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1544   disjointness reasoning but breaking a few old proofs.
  1545 
  1546 * ZF/Update: new theory of function updates
  1547     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1548   may also be iterated as in f(a:=b,c:=d,...);
  1549 
  1550 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1551 
  1552 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1553   [previously, this check worked only if the rewrite rule was unconditional]
  1554   Now rew can involve either definitions or equalities (either == or =).
  1555 
  1556 * case_tac provided for compatibility with HOL
  1557     (like the old excluded_middle_tac, but with subgoals swapped)
  1558 
  1559 
  1560 *** Internal programming interfaces ***
  1561 
  1562 * Pure: several new basic modules made available for general use, see
  1563 also src/Pure/README;
  1564 
  1565 * improved the theory data mechanism to support encapsulation (data
  1566 kind name replaced by private Object.kind, acting as authorization
  1567 key); new type-safe user interface via functor TheoryDataFun; generic
  1568 print_data function becomes basically useless;
  1569 
  1570 * removed global_names compatibility flag -- all theory declarations
  1571 are qualified by default;
  1572 
  1573 * module Pure/Syntax now offers quote / antiquote translation
  1574 functions (useful for Hoare logic etc. with implicit dependencies);
  1575 see HOL/ex/Antiquote for an example use;
  1576 
  1577 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1578 cterm -> thm;
  1579 
  1580 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1581 subgoal;
  1582 
  1583 * Display.print_goals function moved to Locale.print_goals;
  1584 
  1585 * standard print function for goals supports current_goals_markers
  1586 variable for marking begin of proof, end of proof, start of goal; the
  1587 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1588 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1589 for example;
  1590 
  1591 
  1592 
  1593 New in Isabelle98 (January 1998)
  1594 --------------------------------
  1595 
  1596 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1597 
  1598 * changed lexical syntax of terms / types: dots made part of long
  1599 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1600 
  1601 * simpset (and claset) reference variable replaced by functions
  1602 simpset / simpset_ref;
  1603 
  1604 * no longer supports theory aliases (via merge) and non-trivial
  1605 implicit merge of thms' signatures;
  1606 
  1607 * most internal names of constants changed due to qualified names;
  1608 
  1609 * changed Pure/Sequence interface (see Pure/seq.ML);
  1610 
  1611 
  1612 *** General Changes ***
  1613 
  1614 * hierachically structured name spaces (for consts, types, axms, thms
  1615 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1616 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1617 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1618 long_names for fully qualified output names; NOTE: ML programs
  1619 (special tactics, packages etc.) referring to internal names may have
  1620 to be adapted to cope with fully qualified names; in case of severe
  1621 backward campatibility problems try setting 'global_names' at compile
  1622 time to have enrything declared within a flat name space; one may also
  1623 fine tune name declarations in theories via the 'global' and 'local'
  1624 section;
  1625 
  1626 * reimplemented the implicit simpset and claset using the new anytype
  1627 data filed in signatures; references simpset:simpset ref etc. are
  1628 replaced by functions simpset:unit->simpset and
  1629 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1630 to patch your ML files accordingly;
  1631 
  1632 * HTML output now includes theory graph data for display with Java
  1633 applet or isatool browser; data generated automatically via isatool
  1634 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1635 
  1636 * defs may now be conditional; improved rewrite_goals_tac to handle
  1637 conditional equations;
  1638 
  1639 * defs now admits additional type arguments, using TYPE('a) syntax;
  1640 
  1641 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1642 creates a new theory node; implicit merge of thms' signatures is
  1643 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1644 transfer:theory->thm->thm in (rare) cases;
  1645 
  1646 * improved handling of draft signatures / theories; draft thms (and
  1647 ctyps, cterms) are automatically promoted to real ones;
  1648 
  1649 * slightly changed interfaces for oracles: admit many per theory, named
  1650 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1651 
  1652 * print_goals: optional output of const types (set show_consts and
  1653 show_types);
  1654 
  1655 * improved output of warnings (###) and errors (***);
  1656 
  1657 * subgoal_tac displays a warning if the new subgoal has type variables;
  1658 
  1659 * removed old README and Makefiles;
  1660 
  1661 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1662 
  1663 * removed obsolete init_pps and init_database;
  1664 
  1665 * deleted the obsolete tactical STATE, which was declared by
  1666     fun STATE tacfun st = tacfun st st;
  1667 
  1668 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1669 (which abbreviates $HOME);
  1670 
  1671 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1672 use isatool fixseq to adapt your ML programs (this works for fully
  1673 qualified references to the Sequence structure only!);
  1674 
  1675 * use_thy no longer requires writable current directory; it always
  1676 reloads .ML *and* .thy file, if either one is out of date;
  1677 
  1678 
  1679 *** Classical Reasoner ***
  1680 
  1681 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1682 tactics that use classical reasoning to simplify a subgoal without
  1683 splitting it into several subgoals;
  1684 
  1685 * Safe_tac: like safe_tac but uses the default claset;
  1686 
  1687 
  1688 *** Simplifier ***
  1689 
  1690 * added simplification meta rules:
  1691     (asm_)(full_)simplify: simpset -> thm -> thm;
  1692 
  1693 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1694 logics (again);
  1695 
  1696 * added prems argument to simplification procedures;
  1697 
  1698 * HOL, FOL, ZF: added infix function `addsplits':
  1699   instead of `<simpset> setloop (split_tac <thms>)'
  1700   you can simply write `<simpset> addsplits <thms>'
  1701 
  1702 
  1703 *** Syntax ***
  1704 
  1705 * TYPE('a) syntax for type reflection terms;
  1706 
  1707 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1708 
  1709 * pretty printer: changed order of mixfix annotation preference (again!);
  1710 
  1711 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1712 
  1713 
  1714 *** HOL ***
  1715 
  1716 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1717   with `addloop' of the simplifier to faciliate case splitting in premises.
  1718 
  1719 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1720 
  1721 * HOL/Auth: new protocol proofs including some for the Internet
  1722   protocol TLS;
  1723 
  1724 * HOL/Map: new theory of `maps' a la VDM;
  1725 
  1726 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1727 cancelling out common nat summands from =, <, <= (in)equalities, or
  1728 differences; simplification procedures nat_cancel_factor for
  1729 cancelling common factor from =, <, <= (in)equalities over natural
  1730 sums; nat_cancel contains both kinds of procedures, it is installed by
  1731 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1732 
  1733 * HOL/simplifier: terms of the form
  1734   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1735   are rewritten to
  1736   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1737   and those of the form
  1738   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1739   are rewritten to
  1740   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1741 
  1742 * HOL/datatype
  1743   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1744 
  1745   P(t_case f1 ... fn x) =
  1746      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1747         ...
  1748        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1749      )
  1750 
  1751   and a theorem `split_t_case_asm' of the form
  1752 
  1753   P(t_case f1 ... fn x) =
  1754     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1755         ...
  1756        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1757      )
  1758   which can be added to a simpset via `addsplits'. The existing theorems
  1759   expand_list_case and expand_option_case have been renamed to
  1760   split_list_case and split_option_case.
  1761 
  1762 * HOL/Arithmetic:
  1763   - `pred n' is automatically converted to `n-1'.
  1764     Users are strongly encouraged not to use `pred' any longer,
  1765     because it will disappear altogether at some point.
  1766   - Users are strongly encouraged to write "0 < n" rather than
  1767     "n ~= 0". Theorems and proof tools have been modified towards this
  1768     `standard'.
  1769 
  1770 * HOL/Lists:
  1771   the function "set_of_list" has been renamed "set" (and its theorems too);
  1772   the function "nth" now takes its arguments in the reverse order and
  1773   has acquired the infix notation "!" as in "xs!n".
  1774 
  1775 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1776 
  1777 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1778   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1779 
  1780 * HOL/record: extensible records with schematic structural subtyping
  1781 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1782 still lacks various theorems and concrete record syntax;
  1783 
  1784 
  1785 *** HOLCF ***
  1786 
  1787 * removed "axioms" and "generated by" sections;
  1788 
  1789 * replaced "ops" section by extended "consts" section, which is capable of
  1790   handling the continuous function space "->" directly;
  1791 
  1792 * domain package:
  1793   . proves theorems immediately and stores them in the theory,
  1794   . creates hierachical name space,
  1795   . now uses normal mixfix annotations (instead of cinfix...),
  1796   . minor changes to some names and values (for consistency),
  1797   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1798   . separator between mutual domain defs: changed "," to "and",
  1799   . improved handling of sort constraints;  now they have to
  1800     appear on the left-hand side of the equations only;
  1801 
  1802 * fixed LAM <x,y,zs>.b syntax;
  1803 
  1804 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1805 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1806 
  1807 
  1808 *** FOL and ZF ***
  1809 
  1810 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1811   with `addloop' of the simplifier to faciliate case splitting in premises.
  1812 
  1813 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1814 in HOL, they strip ALL and --> from proved theorems;
  1815 
  1816 
  1817 
  1818 New in Isabelle94-8 (May 1997)
  1819 ------------------------------
  1820 
  1821 *** General Changes ***
  1822 
  1823 * new utilities to build / run / maintain Isabelle etc. (in parts
  1824 still somewhat experimental); old Makefiles etc. still functional;
  1825 
  1826 * new 'Isabelle System Manual';
  1827 
  1828 * INSTALL text, together with ./configure and ./build scripts;
  1829 
  1830 * reimplemented type inference for greater efficiency, better error
  1831 messages and clean internal interface;
  1832 
  1833 * prlim command for dealing with lots of subgoals (an easier way of
  1834 setting goals_limit);
  1835 
  1836 
  1837 *** Syntax ***
  1838 
  1839 * supports alternative (named) syntax tables (parser and pretty
  1840 printer); internal interface is provided by add_modesyntax(_i);
  1841 
  1842 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1843 be used in conjunction with the Isabelle symbol font; uses the
  1844 "symbols" syntax table;
  1845 
  1846 * added token_translation interface (may translate name tokens in
  1847 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1848 the current print_mode); IMPORTANT: user print translation functions
  1849 are responsible for marking newly introduced bounds
  1850 (Syntax.mark_boundT);
  1851 
  1852 * token translations for modes "xterm" and "xterm_color" that display
  1853 names in bold, underline etc. or colors (which requires a color
  1854 version of xterm);
  1855 
  1856 * infixes may now be declared with names independent of their syntax;
  1857 
  1858 * added typed_print_translation (like print_translation, but may
  1859 access type of constant);
  1860 
  1861 
  1862 *** Classical Reasoner ***
  1863 
  1864 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1865 some limitations.  Blast_tac...
  1866   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1867   + ignores elimination rules that don't have the correct format
  1868         (the conclusion MUST be a formula variable)
  1869   + ignores types, which can make HOL proofs fail
  1870   + rules must not require higher-order unification, e.g. apply_type in ZF
  1871     [message "Function Var's argument not a bound variable" relates to this]
  1872   + its proof strategy is more general but can actually be slower
  1873 
  1874 * substitution with equality assumptions no longer permutes other
  1875 assumptions;
  1876 
  1877 * minor changes in semantics of addafter (now called addaltern); renamed
  1878 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1879 (and access functions for it);
  1880 
  1881 * improved combination of classical reasoner and simplifier:
  1882   + functions for handling clasimpsets
  1883   + improvement of addss: now the simplifier is called _after_ the
  1884     safe steps.
  1885   + safe variant of addss called addSss: uses safe simplifications
  1886     _during_ the safe steps. It is more complete as it allows multiple
  1887     instantiations of unknowns (e.g. with slow_tac).
  1888 
  1889 *** Simplifier ***
  1890 
  1891 * added interface for simplification procedures (functions that
  1892 produce *proven* rewrite rules on the fly, depending on current
  1893 redex);
  1894 
  1895 * ordering on terms as parameter (used for ordered rewriting);
  1896 
  1897 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1898 
  1899 * the solver is now split into a safe and an unsafe part.
  1900 This should be invisible for the normal user, except that the
  1901 functions setsolver and addsolver have been renamed to setSolver and
  1902 addSolver; added safe_asm_full_simp_tac;
  1903 
  1904 
  1905 *** HOL ***
  1906 
  1907 * a generic induction tactic `induct_tac' which works for all datatypes and
  1908 also for type `nat';
  1909 
  1910 * a generic case distinction tactic `exhaust_tac' which works for all
  1911 datatypes and also for type `nat';
  1912 
  1913 * each datatype comes with a function `size';
  1914 
  1915 * patterns in case expressions allow tuple patterns as arguments to
  1916 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1917 
  1918 * primrec now also works with type nat;
  1919 
  1920 * recdef: a new declaration form, allows general recursive functions to be
  1921 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1922 
  1923 * the constant for negation has been renamed from "not" to "Not" to
  1924 harmonize with FOL, ZF, LK, etc.;
  1925 
  1926 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1927 infinite lists;
  1928 
  1929 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1930 
  1931 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1932 problems in commutative rings, using axiomatic type classes for + and *;
  1933 
  1934 * more examples in HOL/MiniML and HOL/Auth;
  1935 
  1936 * more default rewrite rules for quantifiers, union/intersection;
  1937 
  1938 * a new constant `arbitrary == @x.False';
  1939 
  1940 * HOLCF/IOA replaces old HOL/IOA;
  1941 
  1942 * HOLCF changes: derived all rules and arities
  1943   + axiomatic type classes instead of classes
  1944   + typedef instead of faking type definitions
  1945   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1946   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1947   + eliminated the types void, one, tr
  1948   + use unit lift and bool lift (with translations) instead of one and tr
  1949   + eliminated blift from Lift3.thy (use Def instead of blift)
  1950   all eliminated rules are derived as theorems --> no visible changes ;
  1951 
  1952 
  1953 *** ZF ***
  1954 
  1955 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1956 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1957 as ZF_cs addSIs [equalityI];
  1958 
  1959 
  1960 
  1961 New in Isabelle94-7 (November 96)
  1962 ---------------------------------
  1963 
  1964 * allowing negative levels (as offsets) in prlev and choplev;
  1965 
  1966 * super-linear speedup for large simplifications;
  1967 
  1968 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1969 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1970 FAIL); can suppress it using the command Delsimps (ex_simps @
  1971 all_simps); De Morgan laws are also now included, by default;
  1972 
  1973 * improved printing of ==>  :  ~:
  1974 
  1975 * new object-logic "Sequents" adds linear logic, while replacing LK
  1976 and Modal (thanks to Sara Kalvala);
  1977 
  1978 * HOL/Auth: correctness proofs for authentication protocols;
  1979 
  1980 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1981 examples on HOL/Auth);
  1982 
  1983 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1984 the rewriter and classical reasoner simultaneously;
  1985 
  1986 * function uresult no longer returns theorems in "standard" format;
  1987 regain previous version by: val uresult = standard o uresult;
  1988 
  1989 
  1990 
  1991 New in Isabelle94-6
  1992 -------------------
  1993 
  1994 * oracles -- these establish an interface between Isabelle and trusted
  1995 external reasoners, which may deliver results as theorems;
  1996 
  1997 * proof objects (in particular record all uses of oracles);
  1998 
  1999 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2000 
  2001 * "constdefs" section in theory files;
  2002 
  2003 * "primrec" section (HOL) no longer requires names;
  2004 
  2005 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2006 
  2007 
  2008 
  2009 New in Isabelle94-5
  2010 -------------------
  2011 
  2012 * reduced space requirements;
  2013 
  2014 * automatic HTML generation from theories;
  2015 
  2016 * theory files no longer require "..." (quotes) around most types;
  2017 
  2018 * new examples, including two proofs of the Church-Rosser theorem;
  2019 
  2020 * non-curried (1994) version of HOL is no longer distributed;
  2021 
  2022 
  2023 
  2024 New in Isabelle94-4
  2025 -------------------
  2026 
  2027 * greatly reduced space requirements;
  2028 
  2029 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2030 
  2031 * searchable theorem database (see the section "Retrieving theorems" on
  2032 page 8 of the Reference Manual);
  2033 
  2034 * new examples, including Grabczewski's monumental case study of the
  2035 Axiom of Choice;
  2036 
  2037 * The previous version of HOL renamed to Old_HOL;
  2038 
  2039 * The new version of HOL (previously called CHOL) uses a curried syntax
  2040 for functions.  Application looks like f a b instead of f(a,b);
  2041 
  2042 * Mutually recursive inductive definitions finally work in HOL;
  2043 
  2044 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2045 translates to the operator "split";
  2046 
  2047 
  2048 
  2049 New in Isabelle94-3
  2050 -------------------
  2051 
  2052 * new infix operator, addss, allowing the classical reasoner to
  2053 perform simplification at each step of its search.  Example:
  2054         fast_tac (cs addss ss)
  2055 
  2056 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2057 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2058 look like (a,b) instead of <a,b>;
  2059 
  2060 * PLEASE NOTE: CHOL will eventually replace HOL!
  2061 
  2062 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2063 It translates to the operator "split".  A new theory of integers is available;
  2064 
  2065 * In ZF, integer numerals now denote two's-complement binary integers.
  2066 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2067 
  2068 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2069 of the Axiom of Choice;
  2070 
  2071 
  2072 
  2073 New in Isabelle94-2
  2074 -------------------
  2075 
  2076 * Significantly faster resolution;
  2077 
  2078 * the different sections in a .thy file can now be mixed and repeated
  2079 freely;
  2080 
  2081 * Database of theorems for FOL, HOL and ZF.  New
  2082 commands including qed, qed_goal and bind_thm store theorems in the database.
  2083 
  2084 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2085 a given theory (thms_of), or find out what theory a theorem was proved in
  2086 (theory_of_thm);
  2087 
  2088 * Bugs fixed in the inductive definition and datatype packages;
  2089 
  2090 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2091 and HOL_dup_cs obsolete;
  2092 
  2093 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2094 have been removed;
  2095 
  2096 * Simpler definition of function space in ZF;
  2097 
  2098 * new results about cardinal and ordinal arithmetic in ZF;
  2099 
  2100 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2101 types;
  2102 
  2103 
  2104 $Id$