NEWS
author paulson
Thu Dec 20 15:57:29 2001 +0100 (2001-12-20)
changeset 12563 3813bcab493d
parent 12538 150af0a4bb11
child 12564 226873bffa3a
permissions -rw-r--r--
ZF/Main
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (December 2001)
     6 -----------------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol;
    31 
    32 
    33 *** Isar ***
    34 
    35 * Pure/Provers: improved proof by cases and induction;
    36   - 'case' command admits impromptu naming of parameters (such as
    37     "case (Suc n)");
    38   - 'induct' method divinates rule instantiation from the inductive
    39     claim; no longer requires excessive ?P bindings for proper
    40     instantiation of cases;
    41   - 'induct' method properly enumerates all possibilities of set/type
    42     rules; as a consequence facts may be also passed through *type*
    43     rules without further ado;
    44   - 'induct' method now derives symbolic cases from the *rulified*
    45     rule (before it used to rulify cases stemming from the internal
    46     atomized version); this means that the context of a non-atomic
    47     statement becomes is included in the hypothesis, avoiding the
    48     slightly cumbersome show "PROP ?case" form;
    49   - 'induct' may now use elim-style induction rules without chaining
    50     facts, using ``missing'' premises from the goal state; this allows
    51     rules stemming from inductive sets to be applied in unstructured
    52     scripts, while still benefitting from proper handling of non-atomic
    53     statements; NB: major inductive premises need to be put first, all
    54     the rest of the goal is passed through the induction;
    55   - 'induct' proper support for mutual induction involving non-atomic
    56     rule statements (uses the new concept of simultaneous goals, see
    57     below);
    58   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    59   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    60   - moved induct/cases attributes to Pure, methods to Provers;
    61   - generic method setup instantiated for FOL and HOL;
    62 
    63 * Pure: support multiple simultaneous goal statements, for example
    64 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    65 meta-level mechanism, this acts as if several individual goals had
    66 been stated separately; in particular common proof methods need to be
    67 repeated in order to cover all claims; note that a single elimination
    68 step is *not* sufficient to establish the two conjunctions, so this
    69 fails:
    70 
    71   assume "A & B" then have A and B ..   (*".." fails*)
    72 
    73 better use "obtain" in situations as above; alternative refer to
    74 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    75 
    76 * Pure: proper integration with ``locales''; unlike the original
    77 version by Florian Kammüller, Isar locales package high-level proof
    78 contexts rather than raw logical ones (e.g. we admit to include
    79 attributes everywhere); operations on locales include merge and
    80 rename; e.g. see HOL/ex/Locales.thy;
    81 
    82 * Pure: theory goals now support ad-hoc contexts, which are discharged
    83 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    84 coincides with that of a locale body;
    85 
    86 * Pure: renamed "antecedent" case to "rule_context";
    87 
    88 * Pure: added 'corollary' command;
    89 
    90 * Pure: fixed 'token_translation' command;
    91 
    92 * Pure: removed obsolete 'exported' attribute;
    93 
    94 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    95 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    96 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    97 
    98 * Pure: method 'atomize' presents local goal premises as object-level
    99 statements (atomic meta-level propositions); setup controlled via
   100 rewrite rules declarations of 'atomize' attribute; example
   101 application: 'induct' method with proper rule statements in improper
   102 proof *scripts*;
   103 
   104 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   105 now consider the syntactic context of assumptions, giving a better
   106 chance to get type-inference of the arguments right (this is
   107 especially important for locales);
   108 
   109 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   110 mode;
   111 
   112 * Pure/obtain: the formal conclusion "thesis", being marked as
   113 ``internal'', may no longer be reference directly in the text;
   114 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   115 situations;
   116 
   117 * Pure: generic 'sym' attribute which declares a rule both as pure
   118 'elim?' and for the 'symmetric' operation;
   119 
   120 * Pure/Provers/classical: simplified integration with pure rule
   121 attributes and methods; the classical "intro?/elim?/dest?"
   122 declarations coincide with the pure ones; the "rule" method no longer
   123 includes classically swapped intros; "intro" and "elim" methods no
   124 longer pick rules from the context; also got rid of ML declarations
   125 AddXIs/AddXEs/AddXDs; all of this has some potential for
   126 INCOMPATIBILITY;
   127 
   128 * Provers/classical: attribute 'swapped' produces classical inversions
   129 of introduction rules;
   130 
   131 * Provers/simplifier: 'simplified' attribute may refer to explicit
   132 rules instead of full simplifier context; 'iff' attribute handles
   133 conditional rules;
   134 
   135 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   136 
   137 * HOL: 'recdef' now fails on unfinished automated proofs, use
   138 "(permissive)" option to recover old behavior;
   139 
   140 * HOL: 'inductive' no longer features separate (collective) attributes
   141 for 'intros' (was found too confusing);
   142 
   143 * HOL: properly declared induction rules less_induct and
   144 wf_induct_rule;
   145 
   146 * HOLCF: domain package adapted to new-style theories, e.g. see
   147 HOLCF/ex/Dnat.thy;
   148 
   149 * ZF: proper integration of logic-specific tools and packages,
   150 including theory commands '(co)inductive', '(co)datatype',
   151 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   152 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   153 
   154 
   155 *** HOL ***
   156 
   157 * HOL: moved over to sane numeral syntax; the new policy is as
   158 follows:
   159 
   160   - 0 and 1 are polymorphic constants, which are defined on any
   161   numeric type (nat, int, real etc.);
   162 
   163   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   164   binary representation internally;
   165 
   166   - type nat has special constructor Suc, and generally prefers Suc 0
   167   over 1::nat and Suc (Suc 0) over 2::nat;
   168 
   169 This change may cause significant problems of INCOMPATIBILITY; here
   170 are some hints on converting existing sources:
   171 
   172   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   173   entities, so expressions involving "-" (unary or binary minus) need
   174   to be spaced properly;
   175 
   176   - existing occurrences of "1" may need to be constraint "1::nat" or
   177   even replaced by Suc 0; similar for old "2";
   178 
   179   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   180 
   181   - remove all special provisions on numerals in proofs;
   182 
   183 * HOL: the class of all HOL types is now called "type" rather than
   184 "term"; INCOMPATIBILITY, need to adapt references to this type class
   185 in axclass/classes, instance/arities, and (usually rare) occurrences
   186 in typings (of consts etc.); internally the class is called
   187 "HOL.type", ML programs should refer to HOLogic.typeS;
   188 
   189 * HOL/record package improvements:
   190   - new derived operations "fields" to build a partial record section,
   191     "extend" to promote a fixed record to a record scheme, and
   192     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   193     declared as simp by default;
   194   - removed "make_scheme" operations (use "make" with "extend") --
   195     INCOMPATIBILITY;
   196   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   197   - provides cases/induct rules for use with corresponding Isar
   198     methods (for concrete records, record schemes, concrete more
   199     parts, and schematic more parts -- in that order);
   200   - internal definitions directly based on a light-weight abstract
   201     theory of product types over typedef rather than datatype;
   202 
   203 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   204 
   205 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   206 (beware of argument permutation!);
   207 
   208 * HOL: linorder_less_split superseded by linorder_cases;
   209 
   210 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   211 to peripheral theory "Hilbert_Choice";
   212 
   213 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   214 in this (rare) case use:
   215 
   216   delSWrapper "split_all_tac"
   217   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   218 
   219 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   220 MAY FAIL;
   221 
   222 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   223 Isabelle's type classes, ^ on functions and relations has too general
   224 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   225 necessary to attach explicit type constraints;
   226 
   227 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   228 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   229 (eg "compI" -> "rel_compI").
   230 
   231 * HOL: syntax translations now work properly with numerals and records
   232 expressions;
   233 
   234 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   235 of "lam" -- INCOMPATIBILITY;
   236 
   237 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   238 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   239 renamed "Product_Type.unit";
   240 
   241 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   242 Florian Kammüller;
   243 
   244 
   245 *** HOLCF ***
   246 
   247 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
   248 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   249 lift.induct_tac, always use UU instead of Undef;
   250 
   251 
   252 *** ZF ***
   253 
   254 * Theory Main no longer includes AC; for the Axiom of Choice, base your 
   255 theory on Main_ZFC;
   256 
   257 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   258 typeless version of the formalism;
   259 
   260 * ZF/Induct: new directory for examples of inductive definitions,
   261 including theory Multiset for multiset orderings;
   262 
   263 * ZF: the integer library now covers quotients and remainders, with
   264 many laws relating division to addition, multiplication, etc.;
   265 
   266 
   267 *** General ***
   268 
   269 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   270 variable proof controls level of detail: 0 = no proofs (only oracle
   271 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   272 also ref manual for further ML interfaces;
   273 
   274 * Pure/axclass: removed obsolete ML interface
   275 goal_subclass/goal_arity;
   276 
   277 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   278 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   279 separate tokens, so expressions involving minus need to be spaced
   280 properly;
   281 
   282 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   283 rather than "infixl" or "infixr";
   284 
   285 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   286 sort constraint specifications in type inference; e.g. "x::_::foo"
   287 ensures that the type of "x" is of sort "foo" (but not necessarily a
   288 type variable);
   289 
   290 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   291 control output of nested => (types); the default behavior is
   292 "type_brackets";
   293 
   294 * Pure/syntax: builtin parse translation for "_constify" turns valued
   295 tokens into AST constants;
   296 
   297 * Pure/syntax: prefer later declarations of translations and print
   298 translation functions; potential INCOMPATIBILITY: need to reverse
   299 multiple declarations for same syntax element constant;
   300 
   301 * Provers/classical: renamed addaltern to addafter, addSaltern to
   302 addSafter;
   303 
   304 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   305 as well;
   306 
   307 * system: tested support for MacOS X; should be able to get Isabelle +
   308 Proof General to work in a plain Terminal after installing Poly/ML
   309 (e.g. from the Isabelle distribution area) and GNU bash alone
   310 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   311 support requires further installations, e.g. from
   312 http://fink.sourceforge.net/);
   313 
   314 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   315 
   316 * system: Proof General keywords specification is now part of the
   317 Isabelle distribution (see etc/isar-keywords.el);
   318 
   319 * system: smart selection of Isabelle process versus Isabelle
   320 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   321 run both "isabelle" and "Isabelle" even if file names are badly
   322 damaged (executable inspects the case of the first letter of its own
   323 name); added separate "isabelle-process" and "isabelle-interface";
   324 
   325 * system: refrain from any attempt at filtering input streams; no
   326 longer support ``8bit'' encoding of old isabelle font, instead proper
   327 iso-latin characters may now be used; the related isatools
   328 "symbolinput" and "nonascii" have disappeared as well;
   329 
   330 * system: removed old "xterm" interface (the print modes "xterm" and
   331 "xterm_color" are still available for direct use in a suitable
   332 terminal);
   333 
   334 
   335 
   336 New in Isabelle99-2 (February 2001)
   337 -----------------------------------
   338 
   339 *** Overview of INCOMPATIBILITIES ***
   340 
   341 * HOL: please note that theories in the Library and elsewhere often use the
   342 new-style (Isar) format; to refer to their theorems in an ML script you must
   343 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   344 
   345 * HOL: inductive package no longer splits induction rule aggressively,
   346 but only as far as specified by the introductions given; the old
   347 format may be recovered via ML function complete_split_rule or attribute
   348 'split_rule (complete)';
   349 
   350 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   351 gfp_Tarski to gfp_unfold;
   352 
   353 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   354 
   355 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   356 relation); infix "^^" has been renamed "``"; infix "``" has been
   357 renamed "`"; "univalent" has been renamed "single_valued";
   358 
   359 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   360 operation;
   361 
   362 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   363 
   364 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   365 
   366 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   367 consequence, it is no longer monotonic wrt. the local goal context
   368 (which is now passed through the inductive cases);
   369 
   370 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   371 \<gg> to \<ggreater>;
   372 
   373 
   374 *** Document preparation ***
   375 
   376 * \isabellestyle{NAME} selects version of Isabelle output (currently
   377 available: are "it" for near math-mode best-style output, "sl" for
   378 slanted text style, and "tt" for plain type-writer; if no
   379 \isabellestyle command is given, output is according to slanted
   380 type-writer);
   381 
   382 * support sub/super scripts (for single symbols only), input syntax is
   383 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   384 
   385 * some more standard symbols; see Appendix A of the system manual for
   386 the complete list of symbols defined in isabellesym.sty;
   387 
   388 * improved isabelle style files; more abstract symbol implementation
   389 (should now use \isamath{...} and \isatext{...} in custom symbol
   390 definitions);
   391 
   392 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   393 state; Note that presentation of goal states does not conform to
   394 actual human-readable proof documents.  Please do not include goal
   395 states into document output unless you really know what you are doing!
   396 
   397 * proper indentation of antiquoted output with proportional LaTeX
   398 fonts;
   399 
   400 * no_document ML operator temporarily disables LaTeX document
   401 generation;
   402 
   403 * isatool unsymbolize tunes sources for plain ASCII communication;
   404 
   405 
   406 *** Isar ***
   407 
   408 * Pure: Isar now suffers initial goal statements to contain unbound
   409 schematic variables (this does not conform to actual readable proof
   410 documents, due to unpredictable outcome and non-compositional proof
   411 checking); users who know what they are doing may use schematic goals
   412 for Prolog-style synthesis of proven results;
   413 
   414 * Pure: assumption method (an implicit finishing) now handles actual
   415 rules as well;
   416 
   417 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   418 initial goal, declare "that" only as Pure intro (only for single
   419 steps); the "that" rule assumption may now be involved in implicit
   420 finishing, thus ".." becomes a feasible for trivial obtains;
   421 
   422 * Pure: default proof step now includes 'intro_classes'; thus trivial
   423 instance proofs may be performed by "..";
   424 
   425 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   426 statements as well;
   427 
   428 * Pure: more robust selection of calculational rules;
   429 
   430 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   431 rule (as well as the assumption rule);
   432 
   433 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   434 lemmas, using the graph browser tool;
   435 
   436 * Pure: predict failure of "show" in interactive mode;
   437 
   438 * Pure: 'thms_containing' now takes actual terms as arguments;
   439 
   440 * HOL: improved method 'induct' --- now handles non-atomic goals
   441 (potential INCOMPATIBILITY); tuned error handling;
   442 
   443 * HOL: cases and induct rules now provide explicit hints about the
   444 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   445 any remaining facts are inserted into the goal verbatim;
   446 
   447 * HOL: local contexts (aka cases) may now contain term bindings as
   448 well; the 'cases' and 'induct' methods new provide a ?case binding for
   449 the result to be shown in each case;
   450 
   451 * HOL: added 'recdef_tc' command;
   452 
   453 * isatool convert assists in eliminating legacy ML scripts;
   454 
   455 
   456 *** HOL ***
   457 
   458 * HOL/Library: a collection of generic theories to be used together
   459 with main HOL; the theory loader path already includes this directory
   460 by default; the following existing theories have been moved here:
   461 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   462 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   463 
   464 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   465 modelling and verification task performed in Isabelle/HOL +
   466 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   467 
   468 * HOL/Algebra: special summation operator SUM no longer exists, it has
   469 been replaced by setsum; infix 'assoc' now has priority 50 (like
   470 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   471 'domain', this makes the theory consistent with mathematical
   472 literature;
   473 
   474 * HOL basics: added overloaded operations "inverse" and "divide"
   475 (infix "/"), syntax for generic "abs" operation, generic summation
   476 operator \<Sum>;
   477 
   478 * HOL/typedef: simplified package, provide more useful rules (see also
   479 HOL/subset.thy);
   480 
   481 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   482 now expressed as a proper nested rule (old-style tactic scripts may
   483 require atomize_strip_tac to cope with non-atomic premises);
   484 
   485 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   486 to "split_conv" (old name still available for compatibility);
   487 
   488 * HOL: improved concrete syntax for strings (e.g. allows translation
   489 rules with string literals);
   490 
   491 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   492  and Fleuriot's mechanization of analysis, including the transcendental
   493  functions for the reals;
   494 
   495 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   496 
   497 
   498 *** CTT ***
   499 
   500 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   501 "lam" is displayed as TWO lambda-symbols
   502 
   503 * CTT: theory Main now available, containing everything (that is, Bool
   504 and Arith);
   505 
   506 
   507 *** General ***
   508 
   509 * Pure: the Simplifier has been implemented properly as a derived rule
   510 outside of the actual kernel (at last!); the overall performance
   511 penalty in practical applications is about 50%, while reliability of
   512 the Isabelle inference kernel has been greatly improved;
   513 
   514 * print modes "brackets" and "no_brackets" control output of nested =>
   515 (types) and ==> (props); the default behaviour is "brackets";
   516 
   517 * Provers: fast_tac (and friends) now handle actual object-logic rules
   518 as assumptions as well;
   519 
   520 * system: support Poly/ML 4.0;
   521 
   522 * system: isatool install handles KDE version 1 or 2;
   523 
   524 
   525 
   526 New in Isabelle99-1 (October 2000)
   527 ----------------------------------
   528 
   529 *** Overview of INCOMPATIBILITIES ***
   530 
   531 * HOL: simplification of natural numbers is much changed; to partly
   532 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   533 issue the following ML commands:
   534 
   535   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   536   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   537 
   538 * HOL: simplification no longer dives into case-expressions; this is
   539 controlled by "t.weak_case_cong" for each datatype t;
   540 
   541 * HOL: nat_less_induct renamed to less_induct;
   542 
   543 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   544 fixsome to patch .thy and .ML sources automatically;
   545 
   546   select_equality  -> some_equality
   547   select_eq_Ex     -> some_eq_ex
   548   selectI2EX       -> someI2_ex
   549   selectI2         -> someI2
   550   selectI          -> someI
   551   select1_equality -> some1_equality
   552   Eps_sym_eq       -> some_sym_eq_trivial
   553   Eps_eq           -> some_eq_trivial
   554 
   555 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   556 
   557 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   558 instead);
   559 
   560 * HOL: the recursion equations generated by 'recdef' are now called
   561 f.simps instead of f.rules;
   562 
   563 * HOL: qed_spec_mp now also handles bounded ALL as well;
   564 
   565 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   566 sometimes be needed;
   567 
   568 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   569 
   570 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   571 
   572 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   573 product is now "<*>" instead of "Times"; the lexicographic product is
   574 now "<*lex*>" instead of "**";
   575 
   576 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   577 of main HOL, but was unused); better use HOL's datatype package;
   578 
   579 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   580 the old syntax may be recovered as follows:
   581 
   582   syntax (symbols)
   583     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   584       (infixl "\\<oplus>" 100)
   585 
   586 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   587 
   588 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   589 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   590 internally;
   591 
   592 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   593 changed from A/r to A//r;
   594 
   595 * ZF: new treatment of arithmetic (nat & int) may break some old
   596 proofs;
   597 
   598 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   599 rulify -> rule_format, elimify -> elim_format, ...);
   600 
   601 * Isar/Provers: intro/elim/dest attributes changed; renamed
   602 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   603 should have to change intro!! to intro? only); replaced "delrule" by
   604 "rule del";
   605 
   606 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   607 
   608 * Provers: strengthened force_tac by using new first_best_tac;
   609 
   610 * LaTeX document preparation: several changes of isabelle.sty (see
   611 lib/texinputs);
   612 
   613 
   614 *** Document preparation ***
   615 
   616 * formal comments (text blocks etc.) in new-style theories may now
   617 contain antiquotations of thm/prop/term/typ/text to be presented
   618 according to latex print mode; concrete syntax is like this:
   619 @{term[show_types] "f(x) = a + x"};
   620 
   621 * isatool mkdir provides easy setup of Isabelle session directories,
   622 including proper document sources;
   623 
   624 * generated LaTeX sources are now deleted after successful run
   625 (isatool document -c); may retain a copy somewhere else via -D option
   626 of isatool usedir;
   627 
   628 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   629 style files, achieving self-contained LaTeX sources and simplifying
   630 LaTeX debugging;
   631 
   632 * old-style theories now produce (crude) LaTeX output as well;
   633 
   634 * browser info session directories are now self-contained (may be put
   635 on WWW server seperately); improved graphs of nested sessions; removed
   636 graph for 'all sessions';
   637 
   638 * several improvements in isabelle style files; \isabellestyle{it}
   639 produces fake math mode output; \isamarkupheader is now \section by
   640 default; see lib/texinputs/isabelle.sty etc.;
   641 
   642 
   643 *** Isar ***
   644 
   645 * Isar/Pure: local results and corresponding term bindings are now
   646 subject to Hindley-Milner polymorphism (similar to ML); this
   647 accommodates incremental type-inference very nicely;
   648 
   649 * Isar/Pure: new derived language element 'obtain' supports
   650 generalized existence reasoning;
   651 
   652 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   653 support accumulation of results, without applying any rules yet;
   654 useful to collect intermediate results without explicit name
   655 references, and for use with transitivity rules with more than 2
   656 premises;
   657 
   658 * Isar/Pure: scalable support for case-analysis type proofs: new
   659 'case' language element refers to local contexts symbolically, as
   660 produced by certain proof methods; internally, case names are attached
   661 to theorems as "tags";
   662 
   663 * Isar/Pure: theory command 'hide' removes declarations from
   664 class/type/const name spaces;
   665 
   666 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   667 indicate potential overloading;
   668 
   669 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   670 
   671 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   672 "{a,b,c}" instead of {a,b,c};
   673 
   674 * Isar/Pure now provides its own version of intro/elim/dest
   675 attributes; useful for building new logics, but beware of confusion
   676 with the version in Provers/classical;
   677 
   678 * Isar/Pure: the local context of (non-atomic) goals is provided via
   679 case name 'antecedent';
   680 
   681 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   682 to the current context is now done automatically);
   683 
   684 * Isar/Pure: theory command 'method_setup' provides a simple interface
   685 for definining proof methods in ML;
   686 
   687 * Isar/Provers: intro/elim/dest attributes changed; renamed
   688 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   689 most cases, one should have to change intro!! to intro? only);
   690 replaced "delrule" by "rule del";
   691 
   692 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   693 'symmetric' attribute (the latter supercedes [RS sym]);
   694 
   695 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   696 method modifier); 'simp' method: 'only:' modifier removes loopers as
   697 well (including splits);
   698 
   699 * Isar/Provers: Simplifier and Classical methods now support all kind
   700 of modifiers used in the past, including 'cong', 'iff', etc.
   701 
   702 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   703 of Simplifier and Classical reasoner);
   704 
   705 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   706 now support named cases; major packages (inductive, datatype, primrec,
   707 recdef) support case names and properly name parameters;
   708 
   709 * Isar/HOL: new transitivity rules for substitution in inequalities --
   710 monotonicity conditions are extracted to be proven at end of
   711 calculations;
   712 
   713 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   714 method anyway;
   715 
   716 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   717 split_if split_if_asm; datatype package provides theorems foo.splits =
   718 foo.split foo.split_asm for each datatype;
   719 
   720 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   721 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   722 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   723 use "(cases (simplified))" method in proper proof texts);
   724 
   725 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   726 
   727 * Isar: names of theorems etc. may be natural numbers as well;
   728 
   729 * Isar: 'pr' command: optional arguments for goals_limit and
   730 ProofContext.prems_limit; no longer prints theory contexts, but only
   731 proof states;
   732 
   733 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   734 additional print modes to be specified; e.g. "pr(latex)" will print
   735 proof state according to the Isabelle LaTeX style;
   736 
   737 * Isar: improved support for emulating tactic scripts, including proof
   738 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   739 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   740 (for HOL datatypes);
   741 
   742 * Isar: simplified (more robust) goal selection of proof methods: 1st
   743 goal, all goals, or explicit goal specifier (tactic emulation); thus
   744 'proof method scripts' have to be in depth-first order;
   745 
   746 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   747 
   748 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   749 should instead use individual commands for printing items
   750 (print_commands, print_methods etc.);
   751 
   752 * Isar: added 'nothing' --- the empty list of theorems;
   753 
   754 
   755 *** HOL ***
   756 
   757 * HOL/MicroJava: formalization of a fragment of Java, together with a
   758 corresponding virtual machine and a specification of its bytecode
   759 verifier and a lightweight bytecode verifier, including proofs of
   760 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   761 Cornelia Pusch (see also the homepage of project Bali at
   762 http://isabelle.in.tum.de/Bali/);
   763 
   764 * HOL/Algebra: new theory of rings and univariate polynomials, by
   765 Clemens Ballarin;
   766 
   767 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   768 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   769 Rasmussen;
   770 
   771 * HOL/Lattice: fundamental concepts of lattice theory and order
   772 structures, including duals, properties of bounds versus algebraic
   773 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   774 Theorem for complete lattices etc.; may also serve as a demonstration
   775 for abstract algebraic reasoning using axiomatic type classes, and
   776 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   777 
   778 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   779 von Oheimb;
   780 
   781 * HOL/IMPP: extension of IMP with local variables and mutually
   782 recursive procedures, by David von Oheimb;
   783 
   784 * HOL/Lambda: converted into new-style theory and document;
   785 
   786 * HOL/ex/Multiquote: example of multiple nested quotations and
   787 anti-quotations -- basically a generalized version of de-Bruijn
   788 representation; very useful in avoiding lifting of operations;
   789 
   790 * HOL/record: added general record equality rule to simpset; fixed
   791 select-update simplification procedure to handle extended records as
   792 well; admit "r" as field name;
   793 
   794 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   795 other numeric types and also as the identity of groups, rings, etc.;
   796 
   797 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   798 Types nat and int belong to this axclass;
   799 
   800 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   801    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   802    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   803   two terms #m*u and #n*u are replaced by #(m+n)*u
   804     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   805   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   806     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   807 
   808 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   809 powerful prover for predicate logic but knows nothing of clasets; see
   810 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   811 
   812 * HOL: new version of "case_tac" subsumes both boolean case split and
   813 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   814 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   815 
   816 * HOL: simplification no longer dives into case-expressions: only the
   817 selector expression is simplified, but not the remaining arms; to
   818 enable full simplification of case-expressions for datatype t, you may
   819 remove t.weak_case_cong from the simpset, either globally (Delcongs
   820 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   821 
   822 * HOL/recdef: the recursion equations generated by 'recdef' for
   823 function 'f' are now called f.simps instead of f.rules; if all
   824 termination conditions are proved automatically, these simplification
   825 rules are added to the simpset, as in primrec; rules may be named
   826 individually as well, resulting in a separate list of theorems for
   827 each equation;
   828 
   829 * HOL/While is a new theory that provides a while-combinator. It
   830 permits the definition of tail-recursive functions without the
   831 provision of a termination measure. The latter is necessary once the
   832 invariant proof rule for while is applied.
   833 
   834 * HOL: new (overloaded) notation for the set of elements below/above
   835 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   836 
   837 * HOL: theorems impI, allI, ballI bound as "strip";
   838 
   839 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   840 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   841 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   842 
   843 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   844 
   845 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   846 main HOL, but was unused);
   847 
   848 * HOL: fewer consts declared as global (e.g. have to refer to
   849 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   850 
   851 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   852 in case of overlap with user translations (e.g. judgements over
   853 tuples); (note that the underlying logical represenation is still
   854 bogus);
   855 
   856 
   857 *** ZF ***
   858 
   859 * ZF: simplification automatically cancels common terms in arithmetic
   860 expressions over nat and int;
   861 
   862 * ZF: new treatment of nat to minimize type-checking: all operators
   863 coerce their operands to a natural number using the function natify,
   864 making the algebraic laws unconditional;
   865 
   866 * ZF: as above, for int: operators coerce their operands to an integer
   867 using the function intify;
   868 
   869 * ZF: the integer library now contains many of the usual laws for the
   870 orderings, including $<=, and monotonicity laws for $+ and $*;
   871 
   872 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   873 simplification;
   874 
   875 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   876 to the simplifier and classical reasoner simultaneously;
   877 
   878 
   879 *** General ***
   880 
   881 * Provers: blast_tac now handles actual object-logic rules as
   882 assumptions; note that auto_tac uses blast_tac internally as well;
   883 
   884 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   885 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   886 
   887 * Provers: delrules now handles destruct rules as well (no longer need
   888 explicit make_elim);
   889 
   890 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   891   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   892 use instead the strong form,
   893   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   894 in HOL, FOL and ZF the function cla_make_elim will create such rules
   895 from destruct-rules;
   896 
   897 * Provers: Simplifier.easy_setup provides a fast path to basic
   898 Simplifier setup for new object-logics;
   899 
   900 * Pure: AST translation rules no longer require constant head on LHS;
   901 
   902 * Pure: improved name spaces: ambiguous output is qualified; support
   903 for hiding of names;
   904 
   905 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   906 XSYMBOL_HOME; no longer need to do manual configuration in most
   907 situations;
   908 
   909 * system: compression of ML heaps images may now be controlled via -c
   910 option of isabelle and isatool usedir (currently only observed by
   911 Poly/ML);
   912 
   913 * system: isatool installfonts may handle X-Symbol fonts as well (very
   914 useful for remote X11);
   915 
   916 * system: provide TAGS file for Isabelle sources;
   917 
   918 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   919 order;
   920 
   921 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   922 timing flag supersedes proof_timing and Toplevel.trace;
   923 
   924 * ML: new combinators |>> and |>>> for incremental transformations
   925 with secondary results (e.g. certain theory extensions):
   926 
   927 * ML: PureThy.add_defs gets additional argument to indicate potential
   928 overloading (usually false);
   929 
   930 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   931 results;
   932 
   933 
   934 
   935 New in Isabelle99 (October 1999)
   936 --------------------------------
   937 
   938 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   939 
   940 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   941 are no longer simplified.  (This allows the simplifier to unfold recursive
   942 functional programs.)  To restore the old behaviour, declare
   943 
   944     Delcongs [if_weak_cong];
   945 
   946 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   947 complement;
   948 
   949 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   950 
   951 * HOL/datatype: mutual_induct_tac no longer exists --
   952   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   953 
   954 * HOL/typedef: fixed type inference for representing set; type
   955 arguments now have to occur explicitly on the rhs as type constraints;
   956 
   957 * ZF: The con_defs part of an inductive definition may no longer refer
   958 to constants declared in the same theory;
   959 
   960 * HOL, ZF: the function mk_cases, generated by the inductive
   961 definition package, has lost an argument.  To simplify its result, it
   962 uses the default simpset instead of a supplied list of theorems.
   963 
   964 * HOL/List: the constructors of type list are now Nil and Cons;
   965 
   966 * Simplifier: the type of the infix ML functions
   967         setSSolver addSSolver setSolver addSolver
   968 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   969 for packaging solvers. A solver is created via
   970         mk_solver: string -> (thm list -> int -> tactic) -> solver
   971 where the string argument is only a comment.
   972 
   973 
   974 *** Proof tools ***
   975 
   976 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   977 decision procedure for linear arithmetic. Currently it is used for
   978 types `nat', `int', and `real' in HOL (see below); it can, should and
   979 will be instantiated for other types and logics as well.
   980 
   981 * The simplifier now accepts rewrite rules with flexible heads, eg
   982      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   983   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   984   matching.
   985 
   986 
   987 *** General ***
   988 
   989 * New Isabelle/Isar subsystem provides an alternative to traditional
   990 tactical theorem proving; together with the ProofGeneral/isar user
   991 interface it offers an interactive environment for developing human
   992 readable proof documents (Isar == Intelligible semi-automated
   993 reasoning); for further information see isatool doc isar-ref,
   994 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   995 
   996 * improved and simplified presentation of theories: better HTML markup
   997 (including colors), graph views in several sizes; isatool usedir now
   998 provides a proper interface for user theories (via -P option); actual
   999 document preparation based on (PDF)LaTeX is available as well (for
  1000 new-style theories only); see isatool doc system for more information;
  1001 
  1002 * native support for Proof General, both for classic Isabelle and
  1003 Isabelle/Isar;
  1004 
  1005 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1006 using the graph browser tool;
  1007 
  1008 * Isabelle manuals now also available as PDF;
  1009 
  1010 * theory loader rewritten from scratch (may not be fully
  1011 bug-compatible); old loadpath variable has been replaced by show_path,
  1012 add_path, del_path, reset_path functions; new operations such as
  1013 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1014 isatool doc ref);
  1015 
  1016 * improved isatool install: option -k creates KDE application icon,
  1017 option -p DIR installs standalone binaries;
  1018 
  1019 * added ML_PLATFORM setting (useful for cross-platform installations);
  1020 more robust handling of platform specific ML images for SML/NJ;
  1021 
  1022 * the settings environment is now statically scoped, i.e. it is never
  1023 created again in sub-processes invoked from isabelle, isatool, or
  1024 Isabelle;
  1025 
  1026 * path element specification '~~' refers to '$ISABELLE_HOME';
  1027 
  1028 * in locales, the "assumes" and "defines" parts may be omitted if
  1029 empty;
  1030 
  1031 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1032 long arrows);
  1033 
  1034 * new print_mode "HTML";
  1035 
  1036 * new flag show_tags controls display of tags of theorems (which are
  1037 basically just comments that may be attached by some tools);
  1038 
  1039 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1040 mode and goal output format:
  1041 
  1042 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1043 244c244
  1044 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1045 ---
  1046 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1047 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1048 181c181
  1049 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1050 ---
  1051 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1052 
  1053 * function bind_thms stores lists of theorems (cf. bind_thm);
  1054 
  1055 * new shorthand tactics ftac, eatac, datac, fatac;
  1056 
  1057 * qed (and friends) now accept "" as result name; in that case the
  1058 theorem is not stored, but proper checks and presentation of the
  1059 result still apply;
  1060 
  1061 * theorem database now also indexes constants "Trueprop", "all",
  1062 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1063 
  1064 
  1065 *** HOL ***
  1066 
  1067 ** HOL arithmetic **
  1068 
  1069 * There are now decision procedures for linear arithmetic over nat and
  1070 int:
  1071 
  1072 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1073 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1074 are treated as atomic; subformulae not involving type `nat' or `int'
  1075 are ignored; quantified subformulae are ignored unless they are
  1076 positive universal or negative existential. The tactic has to be
  1077 invoked by hand and can be a little bit slow. In particular, the
  1078 running time is exponential in the number of occurrences of `min' and
  1079 `max', and `-' on `nat'.
  1080 
  1081 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1082 (negated) (in)equalities among the premises and the conclusion into
  1083 account (i.e. no compound formulae) and does not know about `min' and
  1084 `max', and `-' on `nat'. It is fast and is used automatically by the
  1085 simplifier.
  1086 
  1087 NB: At the moment, these decision procedures do not cope with mixed
  1088 nat/int formulae where the two parts interact, such as `m < n ==>
  1089 int(m) < int(n)'.
  1090 
  1091 * HOL/Numeral provides a generic theory of numerals (encoded
  1092 efficiently as bit strings); setup for types nat/int/real is in place;
  1093 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1094 int, existing theories and proof scripts may require a few additional
  1095 type constraints;
  1096 
  1097 * integer division and remainder can now be performed on constant
  1098 arguments;
  1099 
  1100 * many properties of integer multiplication, division and remainder
  1101 are now available;
  1102 
  1103 * An interface to the Stanford Validity Checker (SVC) is available through the
  1104 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1105 are proved automatically.  SVC must be installed separately, and its results
  1106 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1107 invocation of the underlying oracle).  For SVC see
  1108   http://verify.stanford.edu/SVC
  1109 
  1110 * IsaMakefile: the HOL-Real target now builds an actual image;
  1111 
  1112 
  1113 ** HOL misc **
  1114 
  1115 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1116 (in Isabelle/Isar) -- by Gertrud Bauer;
  1117 
  1118 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1119 analysis for assembly languages with subtypes;
  1120 
  1121 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1122 -- avoids syntactic ambiguities and treats state, transition, and
  1123 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1124 changed syntax and (many) tactics;
  1125 
  1126 * HOL/inductive: Now also handles more general introduction rules such
  1127   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1128   theorems are now maintained within the theory (maintained via the
  1129   "mono" attribute);
  1130 
  1131 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1132   (using function types) such as
  1133 
  1134   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1135 
  1136 * HOL/record: record_simproc (part of the default simpset) takes care
  1137 of selectors applied to updated records; record_split_tac is no longer
  1138 part of the default claset; update_defs may now be removed from the
  1139 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1140 
  1141   claset_ref () := claset() addSWrapper record_split_wrapper;
  1142   Delsimprocs [record_simproc]
  1143 
  1144 * HOL/typedef: fixed type inference for representing set; type
  1145 arguments now have to occur explicitly on the rhs as type constraints;
  1146 
  1147 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1148 names rather than an ML expression;
  1149 
  1150 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1151 supplied later.  Program schemes can be defined, such as
  1152     "While B C s = (if B s then While B C (C s) else s)"
  1153 where the well-founded relation can be chosen after B and C have been given.
  1154 
  1155 * HOL/List: the constructors of type list are now Nil and Cons;
  1156 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1157 course, ML tools referring to List.list.op # etc. have to be adapted;
  1158 
  1159 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1160 disabled by default; run isabelle with option -m HOL to get back to
  1161 the original Gordon/HOL-style output;
  1162 
  1163 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1164 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1165 
  1166 * HOL basic syntax simplified (more orthogonal): all variants of
  1167 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1168 Eps operator is provided as well: "SOME x. P[x]";
  1169 
  1170 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1171 
  1172 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1173 thus available for user theories;
  1174 
  1175 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1176 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1177 time;
  1178 
  1179 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1180 several times and then mp;
  1181 
  1182 
  1183 *** LK ***
  1184 
  1185 * the notation <<...>> is now available as a notation for sequences of
  1186 formulas;
  1187 
  1188 * the simplifier is now installed
  1189 
  1190 * the axiom system has been generalized (thanks to Soren Heilmann)
  1191 
  1192 * the classical reasoner now has a default rule database
  1193 
  1194 
  1195 *** ZF ***
  1196 
  1197 * new primrec section allows primitive recursive functions to be given
  1198 directly (as in HOL) over datatypes and the natural numbers;
  1199 
  1200 * new tactics induct_tac and exhaust_tac for induction (or case
  1201 analysis) over datatypes and the natural numbers;
  1202 
  1203 * the datatype declaration of type T now defines the recursor T_rec;
  1204 
  1205 * simplification automatically does freeness reasoning for datatype
  1206 constructors;
  1207 
  1208 * automatic type-inference, with AddTCs command to insert new
  1209 type-checking rules;
  1210 
  1211 * datatype introduction rules are now added as Safe Introduction rules
  1212 to the claset;
  1213 
  1214 * the syntax "if P then x else y" is now available in addition to
  1215 if(P,x,y);
  1216 
  1217 
  1218 *** Internal programming interfaces ***
  1219 
  1220 * tuned simplifier trace output; new flag debug_simp;
  1221 
  1222 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1223 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1224 
  1225 * AxClass.axclass_tac lost the theory argument;
  1226 
  1227 * tuned current_goals_markers semantics: begin / end goal avoids
  1228 printing empty lines;
  1229 
  1230 * removed prs and prs_fn hook, which was broken because it did not
  1231 include \n in its semantics, forcing writeln to add one
  1232 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1233 string -> unit if you really want to output text without newline;
  1234 
  1235 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1236 plain output, interface builders may have to enable 'isabelle_font'
  1237 mode to get Isabelle font glyphs as before;
  1238 
  1239 * refined token_translation interface; INCOMPATIBILITY: output length
  1240 now of type real instead of int;
  1241 
  1242 * theory loader actions may be traced via new ThyInfo.add_hook
  1243 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1244 your own database of information attached to *whole* theories -- as
  1245 opposed to intra-theory data slots offered via TheoryDataFun;
  1246 
  1247 * proper handling of dangling sort hypotheses (at last!);
  1248 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1249 extra sort hypotheses that can be witnessed from the type signature;
  1250 the force_strip_shyps flag is gone, any remaining shyps are simply
  1251 left in the theorem (with a warning issued by strip_shyps_warning);
  1252 
  1253 
  1254 
  1255 New in Isabelle98-1 (October 1998)
  1256 ----------------------------------
  1257 
  1258 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1259 
  1260 * several changes of automated proof tools;
  1261 
  1262 * HOL: major changes to the inductive and datatype packages, including
  1263 some minor incompatibilities of theory syntax;
  1264 
  1265 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1266 called `inj_on';
  1267 
  1268 * HOL: removed duplicate thms in Arith:
  1269   less_imp_add_less  should be replaced by  trans_less_add1
  1270   le_imp_add_le      should be replaced by  trans_le_add1
  1271 
  1272 * HOL: unary minus is now overloaded (new type constraints may be
  1273 required);
  1274 
  1275 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1276 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1277 now taken as an integer constant.
  1278 
  1279 * Pure: ML function 'theory_of' renamed to 'theory';
  1280 
  1281 
  1282 *** Proof tools ***
  1283 
  1284 * Simplifier:
  1285   1. Asm_full_simp_tac is now more aggressive.
  1286      1. It will sometimes reorient premises if that increases their power to
  1287         simplify.
  1288      2. It does no longer proceed strictly from left to right but may also
  1289         rotate premises to achieve further simplification.
  1290      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1291      old Asm_full_simp_tac in that it does not rotate premises.
  1292   2. The simplifier now knows a little bit about nat-arithmetic.
  1293 
  1294 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1295 allows for selected deletion of wrappers, by introduction of names for
  1296 wrapper functionals.  This implies that addbefore, addSbefore,
  1297 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1298 and that adding two tactics with the same name overwrites the first
  1299 one (emitting a warning).
  1300   type wrapper = (int -> tactic) -> (int -> tactic)
  1301   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1302   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1303   delWrapper, delSWrapper: claset *  string            -> claset
  1304   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1305 
  1306 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1307 semantics; addbefore now affects only the unsafe part of step_tac
  1308 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1309 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1310 by Force_tac;
  1311 
  1312 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1313 compWrapper; added safe wrapper (and access functions for it);
  1314 
  1315 * HOL/split_all_tac is now much faster and fails if there is nothing
  1316 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1317 and the names of the automatically generated variables have changed.
  1318 split_all_tac has moved within claset() from unsafe wrappers to safe
  1319 wrappers, which means that !!-bound variables are split much more
  1320 aggressively, and safe_tac and clarify_tac now split such variables.
  1321 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1322 Note: the same holds for record_split_tac, which does the job of
  1323 split_all_tac for record fields.
  1324 
  1325 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1326 permanently to the default simpset using Addsplits just like
  1327 Addsimps. They can be removed via Delsplits just like
  1328 Delsimps. Lower-case versions are also available.
  1329 
  1330 * HOL/Simplifier: The rule split_if is now part of the default
  1331 simpset. This means that the simplifier will eliminate all occurrences
  1332 of if-then-else in the conclusion of a goal. To prevent this, you can
  1333 either remove split_if completely from the default simpset by
  1334 `Delsplits [split_if]' or remove it in a specific call of the
  1335 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1336 other case splitting rules to/from the default simpset: every datatype
  1337 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1338 t is the name of the datatype).
  1339 
  1340 * Classical reasoner / Simplifier combination: new force_tac (and
  1341 derivatives Force_tac, force) combines rewriting and classical
  1342 reasoning (and whatever other tools) similarly to auto_tac, but is
  1343 aimed to solve the given subgoal completely.
  1344 
  1345 
  1346 *** General ***
  1347 
  1348 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1349 and `goalw': the theory is no longer needed as an explicit argument -
  1350 the current theory context is used; assumptions are no longer returned
  1351 at the ML-level unless one of them starts with ==> or !!; it is
  1352 recommended to convert to these new commands using isatool fixgoal
  1353 (backup your sources first!);
  1354 
  1355 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1356 the current theory context, and 'theory' to lookup stored theories;
  1357 
  1358 * new theory section 'locale' for declaring constants, assumptions and
  1359 definitions that have local scope;
  1360 
  1361 * new theory section 'nonterminals' for purely syntactic types;
  1362 
  1363 * new theory section 'setup' for generic ML setup functions
  1364 (e.g. package initialization);
  1365 
  1366 * the distribution now includes Isabelle icons: see
  1367 lib/logo/isabelle-{small,tiny}.xpm;
  1368 
  1369 * isatool install - install binaries with absolute references to
  1370 ISABELLE_HOME/bin;
  1371 
  1372 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1373 
  1374 * print mode 'emacs' reserved for Isamode;
  1375 
  1376 * support multiple print (ast) translations per constant name;
  1377 
  1378 * theorems involving oracles are now printed with a suffixed [!];
  1379 
  1380 
  1381 *** HOL ***
  1382 
  1383 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1384 
  1385 * HOL/inductive package reorganized and improved: now supports mutual
  1386 definitions such as
  1387 
  1388   inductive EVEN ODD
  1389     intrs
  1390       null "0 : EVEN"
  1391       oddI "n : EVEN ==> Suc n : ODD"
  1392       evenI "n : ODD ==> Suc n : EVEN"
  1393 
  1394 new theorem list "elims" contains an elimination rule for each of the
  1395 recursive sets; inductive definitions now handle disjunctive premises
  1396 correctly (also ZF);
  1397 
  1398 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1399 "mutual_induct" no longer exists - the induction rule is always
  1400 contained in "induct";
  1401 
  1402 
  1403 * HOL/datatype package re-implemented and greatly improved: now
  1404 supports mutually recursive datatypes such as
  1405 
  1406   datatype
  1407     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1408             | SUM ('a aexp) ('a aexp)
  1409             | DIFF ('a aexp) ('a aexp)
  1410             | NUM 'a
  1411   and
  1412     'a bexp = LESS ('a aexp) ('a aexp)
  1413             | AND ('a bexp) ('a bexp)
  1414             | OR ('a bexp) ('a bexp)
  1415 
  1416 as well as indirectly recursive datatypes such as
  1417 
  1418   datatype
  1419     ('a, 'b) term = Var 'a
  1420                   | App 'b ((('a, 'b) term) list)
  1421 
  1422 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1423 induction on mutually / indirectly recursive datatypes.
  1424 
  1425 Primrec equations are now stored in theory and can be accessed via
  1426 <function_name>.simps.
  1427 
  1428 INCOMPATIBILITIES:
  1429 
  1430   - Theories using datatypes must now have theory Datatype as an
  1431     ancestor.
  1432   - The specific <typename>.induct_tac no longer exists - use the
  1433     generic induct_tac instead.
  1434   - natE has been renamed to nat.exhaust - use exhaust_tac
  1435     instead of res_inst_tac ... natE. Note that the variable
  1436     names in nat.exhaust differ from the names in natE, this
  1437     may cause some "fragile" proofs to fail.
  1438   - The theorems split_<typename>_case and split_<typename>_case_asm
  1439     have been renamed to <typename>.split and <typename>.split_asm.
  1440   - Since default sorts of type variables are now handled correctly,
  1441     some datatype definitions may have to be annotated with explicit
  1442     sort constraints.
  1443   - Primrec definitions no longer require function name and type
  1444     of recursive argument.
  1445 
  1446 Consider using isatool fixdatatype to adapt your theories and proof
  1447 scripts to the new package (backup your sources first!).
  1448 
  1449 
  1450 * HOL/record package: considerably improved implementation; now
  1451 includes concrete syntax for record types, terms, updates; theorems
  1452 for surjective pairing and splitting !!-bound record variables; proof
  1453 support is as follows:
  1454 
  1455   1) standard conversions (selectors or updates applied to record
  1456 constructor terms) are part of the standard simpset;
  1457 
  1458   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1459 made part of standard simpset and claset via addIffs;
  1460 
  1461   3) a tactic for record field splitting (record_split_tac) is part of
  1462 the standard claset (addSWrapper);
  1463 
  1464 To get a better idea about these rules you may retrieve them via
  1465 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1466 the name of your record type.
  1467 
  1468 The split tactic 3) conceptually simplifies by the following rule:
  1469 
  1470   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1471 
  1472 Thus any record variable that is bound by meta-all will automatically
  1473 blow up into some record constructor term, consequently the
  1474 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1475 solve record problems automatically.
  1476 
  1477 
  1478 * reorganized the main HOL image: HOL/Integ and String loaded by
  1479 default; theory Main includes everything;
  1480 
  1481 * automatic simplification of integer sums and comparisons, using cancellation;
  1482 
  1483 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1484 
  1485 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1486 
  1487 * many new identities for unions, intersections, set difference, etc.;
  1488 
  1489 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1490 called split_if, split_split, split_sum_case and split_nat_case (to go
  1491 with add/delsplits);
  1492 
  1493 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1494 (?x::unit) = (); this is made part of the default simpset, which COULD
  1495 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1496 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1497 unit_abs_eta_conv is added in order to counter the effect of
  1498 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1499 %u.f();
  1500 
  1501 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1502 makes more sense);
  1503 
  1504 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1505   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1506   disjointness reasoning but breaking a few old proofs.
  1507 
  1508 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1509 to 'converse' from 'inverse' (for compatibility with ZF and some
  1510 literature);
  1511 
  1512 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1513 the well-founded relation;
  1514 
  1515 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1516     Compl A.  The "Compl" syntax remains available as input syntax for this
  1517     release ONLY.
  1518 
  1519 * HOL/Update: new theory of function updates:
  1520     f(a:=b) == %x. if x=a then b else f x
  1521 may also be iterated as in f(a:=b,c:=d,...);
  1522 
  1523 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1524 
  1525 * HOL/List:
  1526   - new function list_update written xs[i:=v] that updates the i-th
  1527     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1528   - new function `upt' written [i..j(] which generates the list
  1529     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1530     bound write [i..j], which is a shorthand for [i..j+1(].
  1531   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1532 
  1533 * HOL/Arith:
  1534   - removed 'pred' (predecessor) function;
  1535   - generalized some theorems about n-1;
  1536   - many new laws about "div" and "mod";
  1537   - new laws about greatest common divisors (see theory ex/Primes);
  1538 
  1539 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1540 instead of "inverse";
  1541 
  1542 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1543   of the multiset ordering;
  1544 
  1545 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1546   (not included by default);
  1547 
  1548 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1549 
  1550 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1551   programs, i.e. different program variables may have different types.
  1552 
  1553 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1554   [previously, this check worked only if the rewrite rule was unconditional]
  1555   Now rew can involve either definitions or equalities (either == or =).
  1556 
  1557 
  1558 *** ZF ***
  1559 
  1560 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1561   only the theorems proved on ZF.ML;
  1562 
  1563 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1564   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1565   disjointness reasoning but breaking a few old proofs.
  1566 
  1567 * ZF/Update: new theory of function updates
  1568     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1569   may also be iterated as in f(a:=b,c:=d,...);
  1570 
  1571 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1572 
  1573 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1574   [previously, this check worked only if the rewrite rule was unconditional]
  1575   Now rew can involve either definitions or equalities (either == or =).
  1576 
  1577 * case_tac provided for compatibility with HOL
  1578     (like the old excluded_middle_tac, but with subgoals swapped)
  1579 
  1580 
  1581 *** Internal programming interfaces ***
  1582 
  1583 * Pure: several new basic modules made available for general use, see
  1584 also src/Pure/README;
  1585 
  1586 * improved the theory data mechanism to support encapsulation (data
  1587 kind name replaced by private Object.kind, acting as authorization
  1588 key); new type-safe user interface via functor TheoryDataFun; generic
  1589 print_data function becomes basically useless;
  1590 
  1591 * removed global_names compatibility flag -- all theory declarations
  1592 are qualified by default;
  1593 
  1594 * module Pure/Syntax now offers quote / antiquote translation
  1595 functions (useful for Hoare logic etc. with implicit dependencies);
  1596 see HOL/ex/Antiquote for an example use;
  1597 
  1598 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1599 cterm -> thm;
  1600 
  1601 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1602 subgoal;
  1603 
  1604 * Display.print_goals function moved to Locale.print_goals;
  1605 
  1606 * standard print function for goals supports current_goals_markers
  1607 variable for marking begin of proof, end of proof, start of goal; the
  1608 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1609 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1610 for example;
  1611 
  1612 
  1613 
  1614 New in Isabelle98 (January 1998)
  1615 --------------------------------
  1616 
  1617 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1618 
  1619 * changed lexical syntax of terms / types: dots made part of long
  1620 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1621 
  1622 * simpset (and claset) reference variable replaced by functions
  1623 simpset / simpset_ref;
  1624 
  1625 * no longer supports theory aliases (via merge) and non-trivial
  1626 implicit merge of thms' signatures;
  1627 
  1628 * most internal names of constants changed due to qualified names;
  1629 
  1630 * changed Pure/Sequence interface (see Pure/seq.ML);
  1631 
  1632 
  1633 *** General Changes ***
  1634 
  1635 * hierachically structured name spaces (for consts, types, axms, thms
  1636 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1637 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1638 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1639 long_names for fully qualified output names; NOTE: ML programs
  1640 (special tactics, packages etc.) referring to internal names may have
  1641 to be adapted to cope with fully qualified names; in case of severe
  1642 backward campatibility problems try setting 'global_names' at compile
  1643 time to have enrything declared within a flat name space; one may also
  1644 fine tune name declarations in theories via the 'global' and 'local'
  1645 section;
  1646 
  1647 * reimplemented the implicit simpset and claset using the new anytype
  1648 data filed in signatures; references simpset:simpset ref etc. are
  1649 replaced by functions simpset:unit->simpset and
  1650 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1651 to patch your ML files accordingly;
  1652 
  1653 * HTML output now includes theory graph data for display with Java
  1654 applet or isatool browser; data generated automatically via isatool
  1655 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1656 
  1657 * defs may now be conditional; improved rewrite_goals_tac to handle
  1658 conditional equations;
  1659 
  1660 * defs now admits additional type arguments, using TYPE('a) syntax;
  1661 
  1662 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1663 creates a new theory node; implicit merge of thms' signatures is
  1664 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1665 transfer:theory->thm->thm in (rare) cases;
  1666 
  1667 * improved handling of draft signatures / theories; draft thms (and
  1668 ctyps, cterms) are automatically promoted to real ones;
  1669 
  1670 * slightly changed interfaces for oracles: admit many per theory, named
  1671 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1672 
  1673 * print_goals: optional output of const types (set show_consts and
  1674 show_types);
  1675 
  1676 * improved output of warnings (###) and errors (***);
  1677 
  1678 * subgoal_tac displays a warning if the new subgoal has type variables;
  1679 
  1680 * removed old README and Makefiles;
  1681 
  1682 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1683 
  1684 * removed obsolete init_pps and init_database;
  1685 
  1686 * deleted the obsolete tactical STATE, which was declared by
  1687     fun STATE tacfun st = tacfun st st;
  1688 
  1689 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1690 (which abbreviates $HOME);
  1691 
  1692 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1693 use isatool fixseq to adapt your ML programs (this works for fully
  1694 qualified references to the Sequence structure only!);
  1695 
  1696 * use_thy no longer requires writable current directory; it always
  1697 reloads .ML *and* .thy file, if either one is out of date;
  1698 
  1699 
  1700 *** Classical Reasoner ***
  1701 
  1702 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1703 tactics that use classical reasoning to simplify a subgoal without
  1704 splitting it into several subgoals;
  1705 
  1706 * Safe_tac: like safe_tac but uses the default claset;
  1707 
  1708 
  1709 *** Simplifier ***
  1710 
  1711 * added simplification meta rules:
  1712     (asm_)(full_)simplify: simpset -> thm -> thm;
  1713 
  1714 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1715 logics (again);
  1716 
  1717 * added prems argument to simplification procedures;
  1718 
  1719 * HOL, FOL, ZF: added infix function `addsplits':
  1720   instead of `<simpset> setloop (split_tac <thms>)'
  1721   you can simply write `<simpset> addsplits <thms>'
  1722 
  1723 
  1724 *** Syntax ***
  1725 
  1726 * TYPE('a) syntax for type reflection terms;
  1727 
  1728 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1729 
  1730 * pretty printer: changed order of mixfix annotation preference (again!);
  1731 
  1732 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1733 
  1734 
  1735 *** HOL ***
  1736 
  1737 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1738   with `addloop' of the simplifier to faciliate case splitting in premises.
  1739 
  1740 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1741 
  1742 * HOL/Auth: new protocol proofs including some for the Internet
  1743   protocol TLS;
  1744 
  1745 * HOL/Map: new theory of `maps' a la VDM;
  1746 
  1747 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1748 cancelling out common nat summands from =, <, <= (in)equalities, or
  1749 differences; simplification procedures nat_cancel_factor for
  1750 cancelling common factor from =, <, <= (in)equalities over natural
  1751 sums; nat_cancel contains both kinds of procedures, it is installed by
  1752 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1753 
  1754 * HOL/simplifier: terms of the form
  1755   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1756   are rewritten to
  1757   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1758   and those of the form
  1759   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1760   are rewritten to
  1761   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1762 
  1763 * HOL/datatype
  1764   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1765 
  1766   P(t_case f1 ... fn x) =
  1767      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1768         ...
  1769        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1770      )
  1771 
  1772   and a theorem `split_t_case_asm' of the form
  1773 
  1774   P(t_case f1 ... fn x) =
  1775     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1776         ...
  1777        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1778      )
  1779   which can be added to a simpset via `addsplits'. The existing theorems
  1780   expand_list_case and expand_option_case have been renamed to
  1781   split_list_case and split_option_case.
  1782 
  1783 * HOL/Arithmetic:
  1784   - `pred n' is automatically converted to `n-1'.
  1785     Users are strongly encouraged not to use `pred' any longer,
  1786     because it will disappear altogether at some point.
  1787   - Users are strongly encouraged to write "0 < n" rather than
  1788     "n ~= 0". Theorems and proof tools have been modified towards this
  1789     `standard'.
  1790 
  1791 * HOL/Lists:
  1792   the function "set_of_list" has been renamed "set" (and its theorems too);
  1793   the function "nth" now takes its arguments in the reverse order and
  1794   has acquired the infix notation "!" as in "xs!n".
  1795 
  1796 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1797 
  1798 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1799   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1800 
  1801 * HOL/record: extensible records with schematic structural subtyping
  1802 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1803 still lacks various theorems and concrete record syntax;
  1804 
  1805 
  1806 *** HOLCF ***
  1807 
  1808 * removed "axioms" and "generated by" sections;
  1809 
  1810 * replaced "ops" section by extended "consts" section, which is capable of
  1811   handling the continuous function space "->" directly;
  1812 
  1813 * domain package:
  1814   . proves theorems immediately and stores them in the theory,
  1815   . creates hierachical name space,
  1816   . now uses normal mixfix annotations (instead of cinfix...),
  1817   . minor changes to some names and values (for consistency),
  1818   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1819   . separator between mutual domain defs: changed "," to "and",
  1820   . improved handling of sort constraints;  now they have to
  1821     appear on the left-hand side of the equations only;
  1822 
  1823 * fixed LAM <x,y,zs>.b syntax;
  1824 
  1825 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1826 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1827 
  1828 
  1829 *** FOL and ZF ***
  1830 
  1831 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1832   with `addloop' of the simplifier to faciliate case splitting in premises.
  1833 
  1834 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1835 in HOL, they strip ALL and --> from proved theorems;
  1836 
  1837 
  1838 
  1839 New in Isabelle94-8 (May 1997)
  1840 ------------------------------
  1841 
  1842 *** General Changes ***
  1843 
  1844 * new utilities to build / run / maintain Isabelle etc. (in parts
  1845 still somewhat experimental); old Makefiles etc. still functional;
  1846 
  1847 * new 'Isabelle System Manual';
  1848 
  1849 * INSTALL text, together with ./configure and ./build scripts;
  1850 
  1851 * reimplemented type inference for greater efficiency, better error
  1852 messages and clean internal interface;
  1853 
  1854 * prlim command for dealing with lots of subgoals (an easier way of
  1855 setting goals_limit);
  1856 
  1857 
  1858 *** Syntax ***
  1859 
  1860 * supports alternative (named) syntax tables (parser and pretty
  1861 printer); internal interface is provided by add_modesyntax(_i);
  1862 
  1863 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1864 be used in conjunction with the Isabelle symbol font; uses the
  1865 "symbols" syntax table;
  1866 
  1867 * added token_translation interface (may translate name tokens in
  1868 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1869 the current print_mode); IMPORTANT: user print translation functions
  1870 are responsible for marking newly introduced bounds
  1871 (Syntax.mark_boundT);
  1872 
  1873 * token translations for modes "xterm" and "xterm_color" that display
  1874 names in bold, underline etc. or colors (which requires a color
  1875 version of xterm);
  1876 
  1877 * infixes may now be declared with names independent of their syntax;
  1878 
  1879 * added typed_print_translation (like print_translation, but may
  1880 access type of constant);
  1881 
  1882 
  1883 *** Classical Reasoner ***
  1884 
  1885 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1886 some limitations.  Blast_tac...
  1887   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1888   + ignores elimination rules that don't have the correct format
  1889         (the conclusion MUST be a formula variable)
  1890   + ignores types, which can make HOL proofs fail
  1891   + rules must not require higher-order unification, e.g. apply_type in ZF
  1892     [message "Function Var's argument not a bound variable" relates to this]
  1893   + its proof strategy is more general but can actually be slower
  1894 
  1895 * substitution with equality assumptions no longer permutes other
  1896 assumptions;
  1897 
  1898 * minor changes in semantics of addafter (now called addaltern); renamed
  1899 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1900 (and access functions for it);
  1901 
  1902 * improved combination of classical reasoner and simplifier:
  1903   + functions for handling clasimpsets
  1904   + improvement of addss: now the simplifier is called _after_ the
  1905     safe steps.
  1906   + safe variant of addss called addSss: uses safe simplifications
  1907     _during_ the safe steps. It is more complete as it allows multiple
  1908     instantiations of unknowns (e.g. with slow_tac).
  1909 
  1910 *** Simplifier ***
  1911 
  1912 * added interface for simplification procedures (functions that
  1913 produce *proven* rewrite rules on the fly, depending on current
  1914 redex);
  1915 
  1916 * ordering on terms as parameter (used for ordered rewriting);
  1917 
  1918 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1919 
  1920 * the solver is now split into a safe and an unsafe part.
  1921 This should be invisible for the normal user, except that the
  1922 functions setsolver and addsolver have been renamed to setSolver and
  1923 addSolver; added safe_asm_full_simp_tac;
  1924 
  1925 
  1926 *** HOL ***
  1927 
  1928 * a generic induction tactic `induct_tac' which works for all datatypes and
  1929 also for type `nat';
  1930 
  1931 * a generic case distinction tactic `exhaust_tac' which works for all
  1932 datatypes and also for type `nat';
  1933 
  1934 * each datatype comes with a function `size';
  1935 
  1936 * patterns in case expressions allow tuple patterns as arguments to
  1937 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1938 
  1939 * primrec now also works with type nat;
  1940 
  1941 * recdef: a new declaration form, allows general recursive functions to be
  1942 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1943 
  1944 * the constant for negation has been renamed from "not" to "Not" to
  1945 harmonize with FOL, ZF, LK, etc.;
  1946 
  1947 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1948 infinite lists;
  1949 
  1950 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1951 
  1952 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1953 problems in commutative rings, using axiomatic type classes for + and *;
  1954 
  1955 * more examples in HOL/MiniML and HOL/Auth;
  1956 
  1957 * more default rewrite rules for quantifiers, union/intersection;
  1958 
  1959 * a new constant `arbitrary == @x.False';
  1960 
  1961 * HOLCF/IOA replaces old HOL/IOA;
  1962 
  1963 * HOLCF changes: derived all rules and arities
  1964   + axiomatic type classes instead of classes
  1965   + typedef instead of faking type definitions
  1966   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1967   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1968   + eliminated the types void, one, tr
  1969   + use unit lift and bool lift (with translations) instead of one and tr
  1970   + eliminated blift from Lift3.thy (use Def instead of blift)
  1971   all eliminated rules are derived as theorems --> no visible changes ;
  1972 
  1973 
  1974 *** ZF ***
  1975 
  1976 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1977 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1978 as ZF_cs addSIs [equalityI];
  1979 
  1980 
  1981 
  1982 New in Isabelle94-7 (November 96)
  1983 ---------------------------------
  1984 
  1985 * allowing negative levels (as offsets) in prlev and choplev;
  1986 
  1987 * super-linear speedup for large simplifications;
  1988 
  1989 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1990 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1991 FAIL); can suppress it using the command Delsimps (ex_simps @
  1992 all_simps); De Morgan laws are also now included, by default;
  1993 
  1994 * improved printing of ==>  :  ~:
  1995 
  1996 * new object-logic "Sequents" adds linear logic, while replacing LK
  1997 and Modal (thanks to Sara Kalvala);
  1998 
  1999 * HOL/Auth: correctness proofs for authentication protocols;
  2000 
  2001 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2002 examples on HOL/Auth);
  2003 
  2004 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2005 the rewriter and classical reasoner simultaneously;
  2006 
  2007 * function uresult no longer returns theorems in "standard" format;
  2008 regain previous version by: val uresult = standard o uresult;
  2009 
  2010 
  2011 
  2012 New in Isabelle94-6
  2013 -------------------
  2014 
  2015 * oracles -- these establish an interface between Isabelle and trusted
  2016 external reasoners, which may deliver results as theorems;
  2017 
  2018 * proof objects (in particular record all uses of oracles);
  2019 
  2020 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2021 
  2022 * "constdefs" section in theory files;
  2023 
  2024 * "primrec" section (HOL) no longer requires names;
  2025 
  2026 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2027 
  2028 
  2029 
  2030 New in Isabelle94-5
  2031 -------------------
  2032 
  2033 * reduced space requirements;
  2034 
  2035 * automatic HTML generation from theories;
  2036 
  2037 * theory files no longer require "..." (quotes) around most types;
  2038 
  2039 * new examples, including two proofs of the Church-Rosser theorem;
  2040 
  2041 * non-curried (1994) version of HOL is no longer distributed;
  2042 
  2043 
  2044 
  2045 New in Isabelle94-4
  2046 -------------------
  2047 
  2048 * greatly reduced space requirements;
  2049 
  2050 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2051 
  2052 * searchable theorem database (see the section "Retrieving theorems" on
  2053 page 8 of the Reference Manual);
  2054 
  2055 * new examples, including Grabczewski's monumental case study of the
  2056 Axiom of Choice;
  2057 
  2058 * The previous version of HOL renamed to Old_HOL;
  2059 
  2060 * The new version of HOL (previously called CHOL) uses a curried syntax
  2061 for functions.  Application looks like f a b instead of f(a,b);
  2062 
  2063 * Mutually recursive inductive definitions finally work in HOL;
  2064 
  2065 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2066 translates to the operator "split";
  2067 
  2068 
  2069 
  2070 New in Isabelle94-3
  2071 -------------------
  2072 
  2073 * new infix operator, addss, allowing the classical reasoner to
  2074 perform simplification at each step of its search.  Example:
  2075         fast_tac (cs addss ss)
  2076 
  2077 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2078 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2079 look like (a,b) instead of <a,b>;
  2080 
  2081 * PLEASE NOTE: CHOL will eventually replace HOL!
  2082 
  2083 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2084 It translates to the operator "split".  A new theory of integers is available;
  2085 
  2086 * In ZF, integer numerals now denote two's-complement binary integers.
  2087 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2088 
  2089 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2090 of the Axiom of Choice;
  2091 
  2092 
  2093 
  2094 New in Isabelle94-2
  2095 -------------------
  2096 
  2097 * Significantly faster resolution;
  2098 
  2099 * the different sections in a .thy file can now be mixed and repeated
  2100 freely;
  2101 
  2102 * Database of theorems for FOL, HOL and ZF.  New
  2103 commands including qed, qed_goal and bind_thm store theorems in the database.
  2104 
  2105 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2106 a given theory (thms_of), or find out what theory a theorem was proved in
  2107 (theory_of_thm);
  2108 
  2109 * Bugs fixed in the inductive definition and datatype packages;
  2110 
  2111 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2112 and HOL_dup_cs obsolete;
  2113 
  2114 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2115 have been removed;
  2116 
  2117 * Simpler definition of function space in ZF;
  2118 
  2119 * new results about cardinal and ordinal arithmetic in ZF;
  2120 
  2121 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2122 types;
  2123 
  2124 
  2125 $Id$