NEWS
author nipkow
Thu Dec 20 16:53:51 2001 +0100 (2001-12-20)
changeset 12564 226873bffa3a
parent 12563 3813bcab493d
child 12587 3f3d2ffb5df5
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in Isabelle2001 (December 2001)
     5 -----------------------------------
     6 
     7 *** Document preparation ***
     8 
     9 * greatly simplified document preparation setup, including more
    10 graceful interpretation of isatool usedir -i/-d/-D options, and more
    11 instructive isatool mkdir; users should basically be able to get
    12 started with "isatool mkdir Test && isatool make";
    13 
    14 * theory dependency graph may now be incorporated into documents;
    15 isatool usedir -g true will produce session_graph.eps/.pdf for use
    16 with \includegraphics of LaTeX;
    17 
    18 * proper spacing of consecutive markup elements, especially text
    19 blocks after section headings;
    20 
    21 * support bold style (for single symbols only), input syntax is like
    22 this: "\<^bold>\<alpha>" or "\<^bold>A";
    23 
    24 * \<bullet> is now output as bold \cdot by default, which looks much
    25 better in printed text;
    26 
    27 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    28 note that these symbols are currently unavailable in Proof General /
    29 X-Symbol;
    30 
    31 
    32 *** Isar ***
    33 
    34 * Pure/Provers: improved proof by cases and induction;
    35   - 'case' command admits impromptu naming of parameters (such as
    36     "case (Suc n)");
    37   - 'induct' method divinates rule instantiation from the inductive
    38     claim; no longer requires excessive ?P bindings for proper
    39     instantiation of cases;
    40   - 'induct' method properly enumerates all possibilities of set/type
    41     rules; as a consequence facts may be also passed through *type*
    42     rules without further ado;
    43   - 'induct' method now derives symbolic cases from the *rulified*
    44     rule (before it used to rulify cases stemming from the internal
    45     atomized version); this means that the context of a non-atomic
    46     statement becomes is included in the hypothesis, avoiding the
    47     slightly cumbersome show "PROP ?case" form;
    48   - 'induct' may now use elim-style induction rules without chaining
    49     facts, using ``missing'' premises from the goal state; this allows
    50     rules stemming from inductive sets to be applied in unstructured
    51     scripts, while still benefitting from proper handling of non-atomic
    52     statements; NB: major inductive premises need to be put first, all
    53     the rest of the goal is passed through the induction;
    54   - 'induct' proper support for mutual induction involving non-atomic
    55     rule statements (uses the new concept of simultaneous goals, see
    56     below);
    57   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    58   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    59   - moved induct/cases attributes to Pure, methods to Provers;
    60   - generic method setup instantiated for FOL and HOL;
    61 
    62 * Pure: support multiple simultaneous goal statements, for example
    63 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    64 meta-level mechanism, this acts as if several individual goals had
    65 been stated separately; in particular common proof methods need to be
    66 repeated in order to cover all claims; note that a single elimination
    67 step is *not* sufficient to establish the two conjunctions, so this
    68 fails:
    69 
    70   assume "A & B" then have A and B ..   (*".." fails*)
    71 
    72 better use "obtain" in situations as above; alternative refer to
    73 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    74 
    75 * Pure: proper integration with ``locales''; unlike the original
    76 version by Florian Kammüller, Isar locales package high-level proof
    77 contexts rather than raw logical ones (e.g. we admit to include
    78 attributes everywhere); operations on locales include merge and
    79 rename; e.g. see HOL/ex/Locales.thy;
    80 
    81 * Pure: theory goals now support ad-hoc contexts, which are discharged
    82 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    83 coincides with that of a locale body;
    84 
    85 * Pure: renamed "antecedent" case to "rule_context";
    86 
    87 * Pure: added 'corollary' command;
    88 
    89 * Pure: fixed 'token_translation' command;
    90 
    91 * Pure: removed obsolete 'exported' attribute;
    92 
    93 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    94 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    95 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    96 
    97 * Pure: method 'atomize' presents local goal premises as object-level
    98 statements (atomic meta-level propositions); setup controlled via
    99 rewrite rules declarations of 'atomize' attribute; example
   100 application: 'induct' method with proper rule statements in improper
   101 proof *scripts*;
   102 
   103 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   104 now consider the syntactic context of assumptions, giving a better
   105 chance to get type-inference of the arguments right (this is
   106 especially important for locales);
   107 
   108 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   109 mode;
   110 
   111 * Pure/obtain: the formal conclusion "thesis", being marked as
   112 ``internal'', may no longer be reference directly in the text;
   113 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   114 situations;
   115 
   116 * Pure: generic 'sym' attribute which declares a rule both as pure
   117 'elim?' and for the 'symmetric' operation;
   118 
   119 * Pure/Provers/classical: simplified integration with pure rule
   120 attributes and methods; the classical "intro?/elim?/dest?"
   121 declarations coincide with the pure ones; the "rule" method no longer
   122 includes classically swapped intros; "intro" and "elim" methods no
   123 longer pick rules from the context; also got rid of ML declarations
   124 AddXIs/AddXEs/AddXDs; all of this has some potential for
   125 INCOMPATIBILITY;
   126 
   127 * Provers/classical: attribute 'swapped' produces classical inversions
   128 of introduction rules;
   129 
   130 * Provers/simplifier: 'simplified' attribute may refer to explicit
   131 rules instead of full simplifier context; 'iff' attribute handles
   132 conditional rules;
   133 
   134 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   135 
   136 * HOL: 'recdef' now fails on unfinished automated proofs, use
   137 "(permissive)" option to recover old behavior;
   138 
   139 * HOL: 'inductive' no longer features separate (collective) attributes
   140 for 'intros' (was found too confusing);
   141 
   142 * HOL: properly declared induction rules less_induct and
   143 wf_induct_rule;
   144 
   145 * HOLCF: domain package adapted to new-style theories, e.g. see
   146 HOLCF/ex/Dnat.thy;
   147 
   148 * ZF: proper integration of logic-specific tools and packages,
   149 including theory commands '(co)inductive', '(co)datatype',
   150 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   151 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   152 
   153 
   154 *** HOL ***
   155 
   156 * HOL: moved over to sane numeral syntax; the new policy is as
   157 follows:
   158 
   159   - 0 and 1 are polymorphic constants, which are defined on any
   160   numeric type (nat, int, real etc.);
   161 
   162   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   163   binary representation internally;
   164 
   165   - type nat has special constructor Suc, and generally prefers Suc 0
   166   over 1::nat and Suc (Suc 0) over 2::nat;
   167 
   168 This change may cause significant problems of INCOMPATIBILITY; here
   169 are some hints on converting existing sources:
   170 
   171   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   172   entities, so expressions involving "-" (unary or binary minus) need
   173   to be spaced properly;
   174 
   175   - existing occurrences of "1" may need to be constraint "1::nat" or
   176   even replaced by Suc 0; similar for old "2";
   177 
   178   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   179 
   180   - remove all special provisions on numerals in proofs;
   181 
   182 * HOL: the class of all HOL types is now called "type" rather than
   183 "term"; INCOMPATIBILITY, need to adapt references to this type class
   184 in axclass/classes, instance/arities, and (usually rare) occurrences
   185 in typings (of consts etc.); internally the class is called
   186 "HOL.type", ML programs should refer to HOLogic.typeS;
   187 
   188 * HOL/record package improvements:
   189   - new derived operations "fields" to build a partial record section,
   190     "extend" to promote a fixed record to a record scheme, and
   191     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   192     declared as simp by default;
   193   - removed "make_scheme" operations (use "make" with "extend") --
   194     INCOMPATIBILITY;
   195   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   196   - provides cases/induct rules for use with corresponding Isar
   197     methods (for concrete records, record schemes, concrete more
   198     parts, and schematic more parts -- in that order);
   199   - internal definitions directly based on a light-weight abstract
   200     theory of product types over typedef rather than datatype;
   201 
   202 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   203 
   204 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   205 (beware of argument permutation!);
   206 
   207 * HOL: linorder_less_split superseded by linorder_cases;
   208 
   209 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   210 to peripheral theory "Hilbert_Choice";
   211 
   212 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   213 in this (rare) case use:
   214 
   215   delSWrapper "split_all_tac"
   216   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   217 
   218 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   219 MAY FAIL;
   220 
   221 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   222 Isabelle's type classes, ^ on functions and relations has too general
   223 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   224 necessary to attach explicit type constraints;
   225 
   226 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   227 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   228 (eg "compI" -> "rel_compI").
   229 
   230 * HOL: syntax translations now work properly with numerals and records
   231 expressions;
   232 
   233 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   234 of "lam" -- INCOMPATIBILITY;
   235 
   236 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   237 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   238 renamed "Product_Type.unit";
   239 
   240 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   241 Florian Kammüller;
   242 
   243 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   244 
   245 
   246 *** HOLCF ***
   247 
   248 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
   249 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   250 lift.induct_tac, always use UU instead of Undef;
   251 
   252 
   253 *** ZF ***
   254 
   255 * Theory Main no longer includes AC; for the Axiom of Choice, base your 
   256 theory on Main_ZFC;
   257 
   258 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   259 typeless version of the formalism;
   260 
   261 * ZF/Induct: new directory for examples of inductive definitions,
   262 including theory Multiset for multiset orderings;
   263 
   264 * ZF: the integer library now covers quotients and remainders, with
   265 many laws relating division to addition, multiplication, etc.;
   266 
   267 
   268 *** General ***
   269 
   270 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   271 variable proof controls level of detail: 0 = no proofs (only oracle
   272 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   273 also ref manual for further ML interfaces;
   274 
   275 * Pure/axclass: removed obsolete ML interface
   276 goal_subclass/goal_arity;
   277 
   278 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   279 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   280 separate tokens, so expressions involving minus need to be spaced
   281 properly;
   282 
   283 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   284 rather than "infixl" or "infixr";
   285 
   286 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   287 sort constraint specifications in type inference; e.g. "x::_::foo"
   288 ensures that the type of "x" is of sort "foo" (but not necessarily a
   289 type variable);
   290 
   291 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   292 control output of nested => (types); the default behavior is
   293 "type_brackets";
   294 
   295 * Pure/syntax: builtin parse translation for "_constify" turns valued
   296 tokens into AST constants;
   297 
   298 * Pure/syntax: prefer later declarations of translations and print
   299 translation functions; potential INCOMPATIBILITY: need to reverse
   300 multiple declarations for same syntax element constant;
   301 
   302 * Provers/classical: renamed addaltern to addafter, addSaltern to
   303 addSafter;
   304 
   305 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   306 as well;
   307 
   308 * system: tested support for MacOS X; should be able to get Isabelle +
   309 Proof General to work in a plain Terminal after installing Poly/ML
   310 (e.g. from the Isabelle distribution area) and GNU bash alone
   311 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   312 support requires further installations, e.g. from
   313 http://fink.sourceforge.net/);
   314 
   315 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   316 
   317 * system: Proof General keywords specification is now part of the
   318 Isabelle distribution (see etc/isar-keywords.el);
   319 
   320 * system: smart selection of Isabelle process versus Isabelle
   321 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   322 run both "isabelle" and "Isabelle" even if file names are badly
   323 damaged (executable inspects the case of the first letter of its own
   324 name); added separate "isabelle-process" and "isabelle-interface";
   325 
   326 * system: refrain from any attempt at filtering input streams; no
   327 longer support ``8bit'' encoding of old isabelle font, instead proper
   328 iso-latin characters may now be used; the related isatools
   329 "symbolinput" and "nonascii" have disappeared as well;
   330 
   331 * system: removed old "xterm" interface (the print modes "xterm" and
   332 "xterm_color" are still available for direct use in a suitable
   333 terminal);
   334 
   335 
   336 
   337 New in Isabelle99-2 (February 2001)
   338 -----------------------------------
   339 
   340 *** Overview of INCOMPATIBILITIES ***
   341 
   342 * HOL: please note that theories in the Library and elsewhere often use the
   343 new-style (Isar) format; to refer to their theorems in an ML script you must
   344 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   345 
   346 * HOL: inductive package no longer splits induction rule aggressively,
   347 but only as far as specified by the introductions given; the old
   348 format may be recovered via ML function complete_split_rule or attribute
   349 'split_rule (complete)';
   350 
   351 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   352 gfp_Tarski to gfp_unfold;
   353 
   354 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   355 
   356 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   357 relation); infix "^^" has been renamed "``"; infix "``" has been
   358 renamed "`"; "univalent" has been renamed "single_valued";
   359 
   360 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   361 operation;
   362 
   363 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   364 
   365 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   366 
   367 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   368 consequence, it is no longer monotonic wrt. the local goal context
   369 (which is now passed through the inductive cases);
   370 
   371 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   372 \<gg> to \<ggreater>;
   373 
   374 
   375 *** Document preparation ***
   376 
   377 * \isabellestyle{NAME} selects version of Isabelle output (currently
   378 available: are "it" for near math-mode best-style output, "sl" for
   379 slanted text style, and "tt" for plain type-writer; if no
   380 \isabellestyle command is given, output is according to slanted
   381 type-writer);
   382 
   383 * support sub/super scripts (for single symbols only), input syntax is
   384 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   385 
   386 * some more standard symbols; see Appendix A of the system manual for
   387 the complete list of symbols defined in isabellesym.sty;
   388 
   389 * improved isabelle style files; more abstract symbol implementation
   390 (should now use \isamath{...} and \isatext{...} in custom symbol
   391 definitions);
   392 
   393 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   394 state; Note that presentation of goal states does not conform to
   395 actual human-readable proof documents.  Please do not include goal
   396 states into document output unless you really know what you are doing!
   397 
   398 * proper indentation of antiquoted output with proportional LaTeX
   399 fonts;
   400 
   401 * no_document ML operator temporarily disables LaTeX document
   402 generation;
   403 
   404 * isatool unsymbolize tunes sources for plain ASCII communication;
   405 
   406 
   407 *** Isar ***
   408 
   409 * Pure: Isar now suffers initial goal statements to contain unbound
   410 schematic variables (this does not conform to actual readable proof
   411 documents, due to unpredictable outcome and non-compositional proof
   412 checking); users who know what they are doing may use schematic goals
   413 for Prolog-style synthesis of proven results;
   414 
   415 * Pure: assumption method (an implicit finishing) now handles actual
   416 rules as well;
   417 
   418 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   419 initial goal, declare "that" only as Pure intro (only for single
   420 steps); the "that" rule assumption may now be involved in implicit
   421 finishing, thus ".." becomes a feasible for trivial obtains;
   422 
   423 * Pure: default proof step now includes 'intro_classes'; thus trivial
   424 instance proofs may be performed by "..";
   425 
   426 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   427 statements as well;
   428 
   429 * Pure: more robust selection of calculational rules;
   430 
   431 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   432 rule (as well as the assumption rule);
   433 
   434 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   435 lemmas, using the graph browser tool;
   436 
   437 * Pure: predict failure of "show" in interactive mode;
   438 
   439 * Pure: 'thms_containing' now takes actual terms as arguments;
   440 
   441 * HOL: improved method 'induct' --- now handles non-atomic goals
   442 (potential INCOMPATIBILITY); tuned error handling;
   443 
   444 * HOL: cases and induct rules now provide explicit hints about the
   445 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   446 any remaining facts are inserted into the goal verbatim;
   447 
   448 * HOL: local contexts (aka cases) may now contain term bindings as
   449 well; the 'cases' and 'induct' methods new provide a ?case binding for
   450 the result to be shown in each case;
   451 
   452 * HOL: added 'recdef_tc' command;
   453 
   454 * isatool convert assists in eliminating legacy ML scripts;
   455 
   456 
   457 *** HOL ***
   458 
   459 * HOL/Library: a collection of generic theories to be used together
   460 with main HOL; the theory loader path already includes this directory
   461 by default; the following existing theories have been moved here:
   462 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   463 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   464 
   465 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   466 modelling and verification task performed in Isabelle/HOL +
   467 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   468 
   469 * HOL/Algebra: special summation operator SUM no longer exists, it has
   470 been replaced by setsum; infix 'assoc' now has priority 50 (like
   471 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   472 'domain', this makes the theory consistent with mathematical
   473 literature;
   474 
   475 * HOL basics: added overloaded operations "inverse" and "divide"
   476 (infix "/"), syntax for generic "abs" operation, generic summation
   477 operator \<Sum>;
   478 
   479 * HOL/typedef: simplified package, provide more useful rules (see also
   480 HOL/subset.thy);
   481 
   482 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   483 now expressed as a proper nested rule (old-style tactic scripts may
   484 require atomize_strip_tac to cope with non-atomic premises);
   485 
   486 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   487 to "split_conv" (old name still available for compatibility);
   488 
   489 * HOL: improved concrete syntax for strings (e.g. allows translation
   490 rules with string literals);
   491 
   492 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   493  and Fleuriot's mechanization of analysis, including the transcendental
   494  functions for the reals;
   495 
   496 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   497 
   498 
   499 *** CTT ***
   500 
   501 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   502 "lam" is displayed as TWO lambda-symbols
   503 
   504 * CTT: theory Main now available, containing everything (that is, Bool
   505 and Arith);
   506 
   507 
   508 *** General ***
   509 
   510 * Pure: the Simplifier has been implemented properly as a derived rule
   511 outside of the actual kernel (at last!); the overall performance
   512 penalty in practical applications is about 50%, while reliability of
   513 the Isabelle inference kernel has been greatly improved;
   514 
   515 * print modes "brackets" and "no_brackets" control output of nested =>
   516 (types) and ==> (props); the default behaviour is "brackets";
   517 
   518 * Provers: fast_tac (and friends) now handle actual object-logic rules
   519 as assumptions as well;
   520 
   521 * system: support Poly/ML 4.0;
   522 
   523 * system: isatool install handles KDE version 1 or 2;
   524 
   525 
   526 
   527 New in Isabelle99-1 (October 2000)
   528 ----------------------------------
   529 
   530 *** Overview of INCOMPATIBILITIES ***
   531 
   532 * HOL: simplification of natural numbers is much changed; to partly
   533 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   534 issue the following ML commands:
   535 
   536   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   537   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   538 
   539 * HOL: simplification no longer dives into case-expressions; this is
   540 controlled by "t.weak_case_cong" for each datatype t;
   541 
   542 * HOL: nat_less_induct renamed to less_induct;
   543 
   544 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   545 fixsome to patch .thy and .ML sources automatically;
   546 
   547   select_equality  -> some_equality
   548   select_eq_Ex     -> some_eq_ex
   549   selectI2EX       -> someI2_ex
   550   selectI2         -> someI2
   551   selectI          -> someI
   552   select1_equality -> some1_equality
   553   Eps_sym_eq       -> some_sym_eq_trivial
   554   Eps_eq           -> some_eq_trivial
   555 
   556 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   557 
   558 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   559 instead);
   560 
   561 * HOL: the recursion equations generated by 'recdef' are now called
   562 f.simps instead of f.rules;
   563 
   564 * HOL: qed_spec_mp now also handles bounded ALL as well;
   565 
   566 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   567 sometimes be needed;
   568 
   569 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   570 
   571 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   572 
   573 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   574 product is now "<*>" instead of "Times"; the lexicographic product is
   575 now "<*lex*>" instead of "**";
   576 
   577 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   578 of main HOL, but was unused); better use HOL's datatype package;
   579 
   580 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   581 the old syntax may be recovered as follows:
   582 
   583   syntax (symbols)
   584     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   585       (infixl "\\<oplus>" 100)
   586 
   587 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   588 
   589 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   590 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   591 internally;
   592 
   593 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   594 changed from A/r to A//r;
   595 
   596 * ZF: new treatment of arithmetic (nat & int) may break some old
   597 proofs;
   598 
   599 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   600 rulify -> rule_format, elimify -> elim_format, ...);
   601 
   602 * Isar/Provers: intro/elim/dest attributes changed; renamed
   603 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   604 should have to change intro!! to intro? only); replaced "delrule" by
   605 "rule del";
   606 
   607 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   608 
   609 * Provers: strengthened force_tac by using new first_best_tac;
   610 
   611 * LaTeX document preparation: several changes of isabelle.sty (see
   612 lib/texinputs);
   613 
   614 
   615 *** Document preparation ***
   616 
   617 * formal comments (text blocks etc.) in new-style theories may now
   618 contain antiquotations of thm/prop/term/typ/text to be presented
   619 according to latex print mode; concrete syntax is like this:
   620 @{term[show_types] "f(x) = a + x"};
   621 
   622 * isatool mkdir provides easy setup of Isabelle session directories,
   623 including proper document sources;
   624 
   625 * generated LaTeX sources are now deleted after successful run
   626 (isatool document -c); may retain a copy somewhere else via -D option
   627 of isatool usedir;
   628 
   629 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   630 style files, achieving self-contained LaTeX sources and simplifying
   631 LaTeX debugging;
   632 
   633 * old-style theories now produce (crude) LaTeX output as well;
   634 
   635 * browser info session directories are now self-contained (may be put
   636 on WWW server seperately); improved graphs of nested sessions; removed
   637 graph for 'all sessions';
   638 
   639 * several improvements in isabelle style files; \isabellestyle{it}
   640 produces fake math mode output; \isamarkupheader is now \section by
   641 default; see lib/texinputs/isabelle.sty etc.;
   642 
   643 
   644 *** Isar ***
   645 
   646 * Isar/Pure: local results and corresponding term bindings are now
   647 subject to Hindley-Milner polymorphism (similar to ML); this
   648 accommodates incremental type-inference very nicely;
   649 
   650 * Isar/Pure: new derived language element 'obtain' supports
   651 generalized existence reasoning;
   652 
   653 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   654 support accumulation of results, without applying any rules yet;
   655 useful to collect intermediate results without explicit name
   656 references, and for use with transitivity rules with more than 2
   657 premises;
   658 
   659 * Isar/Pure: scalable support for case-analysis type proofs: new
   660 'case' language element refers to local contexts symbolically, as
   661 produced by certain proof methods; internally, case names are attached
   662 to theorems as "tags";
   663 
   664 * Isar/Pure: theory command 'hide' removes declarations from
   665 class/type/const name spaces;
   666 
   667 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   668 indicate potential overloading;
   669 
   670 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   671 
   672 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   673 "{a,b,c}" instead of {a,b,c};
   674 
   675 * Isar/Pure now provides its own version of intro/elim/dest
   676 attributes; useful for building new logics, but beware of confusion
   677 with the version in Provers/classical;
   678 
   679 * Isar/Pure: the local context of (non-atomic) goals is provided via
   680 case name 'antecedent';
   681 
   682 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   683 to the current context is now done automatically);
   684 
   685 * Isar/Pure: theory command 'method_setup' provides a simple interface
   686 for definining proof methods in ML;
   687 
   688 * Isar/Provers: intro/elim/dest attributes changed; renamed
   689 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   690 most cases, one should have to change intro!! to intro? only);
   691 replaced "delrule" by "rule del";
   692 
   693 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   694 'symmetric' attribute (the latter supercedes [RS sym]);
   695 
   696 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   697 method modifier); 'simp' method: 'only:' modifier removes loopers as
   698 well (including splits);
   699 
   700 * Isar/Provers: Simplifier and Classical methods now support all kind
   701 of modifiers used in the past, including 'cong', 'iff', etc.
   702 
   703 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   704 of Simplifier and Classical reasoner);
   705 
   706 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   707 now support named cases; major packages (inductive, datatype, primrec,
   708 recdef) support case names and properly name parameters;
   709 
   710 * Isar/HOL: new transitivity rules for substitution in inequalities --
   711 monotonicity conditions are extracted to be proven at end of
   712 calculations;
   713 
   714 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   715 method anyway;
   716 
   717 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   718 split_if split_if_asm; datatype package provides theorems foo.splits =
   719 foo.split foo.split_asm for each datatype;
   720 
   721 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   722 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   723 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   724 use "(cases (simplified))" method in proper proof texts);
   725 
   726 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   727 
   728 * Isar: names of theorems etc. may be natural numbers as well;
   729 
   730 * Isar: 'pr' command: optional arguments for goals_limit and
   731 ProofContext.prems_limit; no longer prints theory contexts, but only
   732 proof states;
   733 
   734 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   735 additional print modes to be specified; e.g. "pr(latex)" will print
   736 proof state according to the Isabelle LaTeX style;
   737 
   738 * Isar: improved support for emulating tactic scripts, including proof
   739 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   740 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   741 (for HOL datatypes);
   742 
   743 * Isar: simplified (more robust) goal selection of proof methods: 1st
   744 goal, all goals, or explicit goal specifier (tactic emulation); thus
   745 'proof method scripts' have to be in depth-first order;
   746 
   747 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   748 
   749 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   750 should instead use individual commands for printing items
   751 (print_commands, print_methods etc.);
   752 
   753 * Isar: added 'nothing' --- the empty list of theorems;
   754 
   755 
   756 *** HOL ***
   757 
   758 * HOL/MicroJava: formalization of a fragment of Java, together with a
   759 corresponding virtual machine and a specification of its bytecode
   760 verifier and a lightweight bytecode verifier, including proofs of
   761 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   762 Cornelia Pusch (see also the homepage of project Bali at
   763 http://isabelle.in.tum.de/Bali/);
   764 
   765 * HOL/Algebra: new theory of rings and univariate polynomials, by
   766 Clemens Ballarin;
   767 
   768 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   769 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   770 Rasmussen;
   771 
   772 * HOL/Lattice: fundamental concepts of lattice theory and order
   773 structures, including duals, properties of bounds versus algebraic
   774 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   775 Theorem for complete lattices etc.; may also serve as a demonstration
   776 for abstract algebraic reasoning using axiomatic type classes, and
   777 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   778 
   779 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   780 von Oheimb;
   781 
   782 * HOL/IMPP: extension of IMP with local variables and mutually
   783 recursive procedures, by David von Oheimb;
   784 
   785 * HOL/Lambda: converted into new-style theory and document;
   786 
   787 * HOL/ex/Multiquote: example of multiple nested quotations and
   788 anti-quotations -- basically a generalized version of de-Bruijn
   789 representation; very useful in avoiding lifting of operations;
   790 
   791 * HOL/record: added general record equality rule to simpset; fixed
   792 select-update simplification procedure to handle extended records as
   793 well; admit "r" as field name;
   794 
   795 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   796 other numeric types and also as the identity of groups, rings, etc.;
   797 
   798 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   799 Types nat and int belong to this axclass;
   800 
   801 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   802    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   803    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   804   two terms #m*u and #n*u are replaced by #(m+n)*u
   805     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   806   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   807     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   808 
   809 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   810 powerful prover for predicate logic but knows nothing of clasets; see
   811 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   812 
   813 * HOL: new version of "case_tac" subsumes both boolean case split and
   814 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   815 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   816 
   817 * HOL: simplification no longer dives into case-expressions: only the
   818 selector expression is simplified, but not the remaining arms; to
   819 enable full simplification of case-expressions for datatype t, you may
   820 remove t.weak_case_cong from the simpset, either globally (Delcongs
   821 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   822 
   823 * HOL/recdef: the recursion equations generated by 'recdef' for
   824 function 'f' are now called f.simps instead of f.rules; if all
   825 termination conditions are proved automatically, these simplification
   826 rules are added to the simpset, as in primrec; rules may be named
   827 individually as well, resulting in a separate list of theorems for
   828 each equation;
   829 
   830 * HOL/While is a new theory that provides a while-combinator. It
   831 permits the definition of tail-recursive functions without the
   832 provision of a termination measure. The latter is necessary once the
   833 invariant proof rule for while is applied.
   834 
   835 * HOL: new (overloaded) notation for the set of elements below/above
   836 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   837 
   838 * HOL: theorems impI, allI, ballI bound as "strip";
   839 
   840 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   841 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   842 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   843 
   844 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   845 
   846 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   847 main HOL, but was unused);
   848 
   849 * HOL: fewer consts declared as global (e.g. have to refer to
   850 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   851 
   852 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   853 in case of overlap with user translations (e.g. judgements over
   854 tuples); (note that the underlying logical represenation is still
   855 bogus);
   856 
   857 
   858 *** ZF ***
   859 
   860 * ZF: simplification automatically cancels common terms in arithmetic
   861 expressions over nat and int;
   862 
   863 * ZF: new treatment of nat to minimize type-checking: all operators
   864 coerce their operands to a natural number using the function natify,
   865 making the algebraic laws unconditional;
   866 
   867 * ZF: as above, for int: operators coerce their operands to an integer
   868 using the function intify;
   869 
   870 * ZF: the integer library now contains many of the usual laws for the
   871 orderings, including $<=, and monotonicity laws for $+ and $*;
   872 
   873 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   874 simplification;
   875 
   876 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   877 to the simplifier and classical reasoner simultaneously;
   878 
   879 
   880 *** General ***
   881 
   882 * Provers: blast_tac now handles actual object-logic rules as
   883 assumptions; note that auto_tac uses blast_tac internally as well;
   884 
   885 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   886 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   887 
   888 * Provers: delrules now handles destruct rules as well (no longer need
   889 explicit make_elim);
   890 
   891 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   892   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   893 use instead the strong form,
   894   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   895 in HOL, FOL and ZF the function cla_make_elim will create such rules
   896 from destruct-rules;
   897 
   898 * Provers: Simplifier.easy_setup provides a fast path to basic
   899 Simplifier setup for new object-logics;
   900 
   901 * Pure: AST translation rules no longer require constant head on LHS;
   902 
   903 * Pure: improved name spaces: ambiguous output is qualified; support
   904 for hiding of names;
   905 
   906 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   907 XSYMBOL_HOME; no longer need to do manual configuration in most
   908 situations;
   909 
   910 * system: compression of ML heaps images may now be controlled via -c
   911 option of isabelle and isatool usedir (currently only observed by
   912 Poly/ML);
   913 
   914 * system: isatool installfonts may handle X-Symbol fonts as well (very
   915 useful for remote X11);
   916 
   917 * system: provide TAGS file for Isabelle sources;
   918 
   919 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   920 order;
   921 
   922 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   923 timing flag supersedes proof_timing and Toplevel.trace;
   924 
   925 * ML: new combinators |>> and |>>> for incremental transformations
   926 with secondary results (e.g. certain theory extensions):
   927 
   928 * ML: PureThy.add_defs gets additional argument to indicate potential
   929 overloading (usually false);
   930 
   931 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   932 results;
   933 
   934 
   935 
   936 New in Isabelle99 (October 1999)
   937 --------------------------------
   938 
   939 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   940 
   941 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   942 are no longer simplified.  (This allows the simplifier to unfold recursive
   943 functional programs.)  To restore the old behaviour, declare
   944 
   945     Delcongs [if_weak_cong];
   946 
   947 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   948 complement;
   949 
   950 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   951 
   952 * HOL/datatype: mutual_induct_tac no longer exists --
   953   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   954 
   955 * HOL/typedef: fixed type inference for representing set; type
   956 arguments now have to occur explicitly on the rhs as type constraints;
   957 
   958 * ZF: The con_defs part of an inductive definition may no longer refer
   959 to constants declared in the same theory;
   960 
   961 * HOL, ZF: the function mk_cases, generated by the inductive
   962 definition package, has lost an argument.  To simplify its result, it
   963 uses the default simpset instead of a supplied list of theorems.
   964 
   965 * HOL/List: the constructors of type list are now Nil and Cons;
   966 
   967 * Simplifier: the type of the infix ML functions
   968         setSSolver addSSolver setSolver addSolver
   969 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   970 for packaging solvers. A solver is created via
   971         mk_solver: string -> (thm list -> int -> tactic) -> solver
   972 where the string argument is only a comment.
   973 
   974 
   975 *** Proof tools ***
   976 
   977 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   978 decision procedure for linear arithmetic. Currently it is used for
   979 types `nat', `int', and `real' in HOL (see below); it can, should and
   980 will be instantiated for other types and logics as well.
   981 
   982 * The simplifier now accepts rewrite rules with flexible heads, eg
   983      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   984   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   985   matching.
   986 
   987 
   988 *** General ***
   989 
   990 * New Isabelle/Isar subsystem provides an alternative to traditional
   991 tactical theorem proving; together with the ProofGeneral/isar user
   992 interface it offers an interactive environment for developing human
   993 readable proof documents (Isar == Intelligible semi-automated
   994 reasoning); for further information see isatool doc isar-ref,
   995 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   996 
   997 * improved and simplified presentation of theories: better HTML markup
   998 (including colors), graph views in several sizes; isatool usedir now
   999 provides a proper interface for user theories (via -P option); actual
  1000 document preparation based on (PDF)LaTeX is available as well (for
  1001 new-style theories only); see isatool doc system for more information;
  1002 
  1003 * native support for Proof General, both for classic Isabelle and
  1004 Isabelle/Isar;
  1005 
  1006 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1007 using the graph browser tool;
  1008 
  1009 * Isabelle manuals now also available as PDF;
  1010 
  1011 * theory loader rewritten from scratch (may not be fully
  1012 bug-compatible); old loadpath variable has been replaced by show_path,
  1013 add_path, del_path, reset_path functions; new operations such as
  1014 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1015 isatool doc ref);
  1016 
  1017 * improved isatool install: option -k creates KDE application icon,
  1018 option -p DIR installs standalone binaries;
  1019 
  1020 * added ML_PLATFORM setting (useful for cross-platform installations);
  1021 more robust handling of platform specific ML images for SML/NJ;
  1022 
  1023 * the settings environment is now statically scoped, i.e. it is never
  1024 created again in sub-processes invoked from isabelle, isatool, or
  1025 Isabelle;
  1026 
  1027 * path element specification '~~' refers to '$ISABELLE_HOME';
  1028 
  1029 * in locales, the "assumes" and "defines" parts may be omitted if
  1030 empty;
  1031 
  1032 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1033 long arrows);
  1034 
  1035 * new print_mode "HTML";
  1036 
  1037 * new flag show_tags controls display of tags of theorems (which are
  1038 basically just comments that may be attached by some tools);
  1039 
  1040 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1041 mode and goal output format:
  1042 
  1043 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1044 244c244
  1045 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1046 ---
  1047 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1048 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1049 181c181
  1050 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1051 ---
  1052 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1053 
  1054 * function bind_thms stores lists of theorems (cf. bind_thm);
  1055 
  1056 * new shorthand tactics ftac, eatac, datac, fatac;
  1057 
  1058 * qed (and friends) now accept "" as result name; in that case the
  1059 theorem is not stored, but proper checks and presentation of the
  1060 result still apply;
  1061 
  1062 * theorem database now also indexes constants "Trueprop", "all",
  1063 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1064 
  1065 
  1066 *** HOL ***
  1067 
  1068 ** HOL arithmetic **
  1069 
  1070 * There are now decision procedures for linear arithmetic over nat and
  1071 int:
  1072 
  1073 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1074 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1075 are treated as atomic; subformulae not involving type `nat' or `int'
  1076 are ignored; quantified subformulae are ignored unless they are
  1077 positive universal or negative existential. The tactic has to be
  1078 invoked by hand and can be a little bit slow. In particular, the
  1079 running time is exponential in the number of occurrences of `min' and
  1080 `max', and `-' on `nat'.
  1081 
  1082 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1083 (negated) (in)equalities among the premises and the conclusion into
  1084 account (i.e. no compound formulae) and does not know about `min' and
  1085 `max', and `-' on `nat'. It is fast and is used automatically by the
  1086 simplifier.
  1087 
  1088 NB: At the moment, these decision procedures do not cope with mixed
  1089 nat/int formulae where the two parts interact, such as `m < n ==>
  1090 int(m) < int(n)'.
  1091 
  1092 * HOL/Numeral provides a generic theory of numerals (encoded
  1093 efficiently as bit strings); setup for types nat/int/real is in place;
  1094 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1095 int, existing theories and proof scripts may require a few additional
  1096 type constraints;
  1097 
  1098 * integer division and remainder can now be performed on constant
  1099 arguments;
  1100 
  1101 * many properties of integer multiplication, division and remainder
  1102 are now available;
  1103 
  1104 * An interface to the Stanford Validity Checker (SVC) is available through the
  1105 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1106 are proved automatically.  SVC must be installed separately, and its results
  1107 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1108 invocation of the underlying oracle).  For SVC see
  1109   http://verify.stanford.edu/SVC
  1110 
  1111 * IsaMakefile: the HOL-Real target now builds an actual image;
  1112 
  1113 
  1114 ** HOL misc **
  1115 
  1116 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1117 (in Isabelle/Isar) -- by Gertrud Bauer;
  1118 
  1119 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1120 analysis for assembly languages with subtypes;
  1121 
  1122 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1123 -- avoids syntactic ambiguities and treats state, transition, and
  1124 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1125 changed syntax and (many) tactics;
  1126 
  1127 * HOL/inductive: Now also handles more general introduction rules such
  1128   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1129   theorems are now maintained within the theory (maintained via the
  1130   "mono" attribute);
  1131 
  1132 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1133   (using function types) such as
  1134 
  1135   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1136 
  1137 * HOL/record: record_simproc (part of the default simpset) takes care
  1138 of selectors applied to updated records; record_split_tac is no longer
  1139 part of the default claset; update_defs may now be removed from the
  1140 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1141 
  1142   claset_ref () := claset() addSWrapper record_split_wrapper;
  1143   Delsimprocs [record_simproc]
  1144 
  1145 * HOL/typedef: fixed type inference for representing set; type
  1146 arguments now have to occur explicitly on the rhs as type constraints;
  1147 
  1148 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1149 names rather than an ML expression;
  1150 
  1151 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1152 supplied later.  Program schemes can be defined, such as
  1153     "While B C s = (if B s then While B C (C s) else s)"
  1154 where the well-founded relation can be chosen after B and C have been given.
  1155 
  1156 * HOL/List: the constructors of type list are now Nil and Cons;
  1157 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1158 course, ML tools referring to List.list.op # etc. have to be adapted;
  1159 
  1160 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1161 disabled by default; run isabelle with option -m HOL to get back to
  1162 the original Gordon/HOL-style output;
  1163 
  1164 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1165 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1166 
  1167 * HOL basic syntax simplified (more orthogonal): all variants of
  1168 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1169 Eps operator is provided as well: "SOME x. P[x]";
  1170 
  1171 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1172 
  1173 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1174 thus available for user theories;
  1175 
  1176 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1177 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1178 time;
  1179 
  1180 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1181 several times and then mp;
  1182 
  1183 
  1184 *** LK ***
  1185 
  1186 * the notation <<...>> is now available as a notation for sequences of
  1187 formulas;
  1188 
  1189 * the simplifier is now installed
  1190 
  1191 * the axiom system has been generalized (thanks to Soren Heilmann)
  1192 
  1193 * the classical reasoner now has a default rule database
  1194 
  1195 
  1196 *** ZF ***
  1197 
  1198 * new primrec section allows primitive recursive functions to be given
  1199 directly (as in HOL) over datatypes and the natural numbers;
  1200 
  1201 * new tactics induct_tac and exhaust_tac for induction (or case
  1202 analysis) over datatypes and the natural numbers;
  1203 
  1204 * the datatype declaration of type T now defines the recursor T_rec;
  1205 
  1206 * simplification automatically does freeness reasoning for datatype
  1207 constructors;
  1208 
  1209 * automatic type-inference, with AddTCs command to insert new
  1210 type-checking rules;
  1211 
  1212 * datatype introduction rules are now added as Safe Introduction rules
  1213 to the claset;
  1214 
  1215 * the syntax "if P then x else y" is now available in addition to
  1216 if(P,x,y);
  1217 
  1218 
  1219 *** Internal programming interfaces ***
  1220 
  1221 * tuned simplifier trace output; new flag debug_simp;
  1222 
  1223 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1224 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1225 
  1226 * AxClass.axclass_tac lost the theory argument;
  1227 
  1228 * tuned current_goals_markers semantics: begin / end goal avoids
  1229 printing empty lines;
  1230 
  1231 * removed prs and prs_fn hook, which was broken because it did not
  1232 include \n in its semantics, forcing writeln to add one
  1233 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1234 string -> unit if you really want to output text without newline;
  1235 
  1236 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1237 plain output, interface builders may have to enable 'isabelle_font'
  1238 mode to get Isabelle font glyphs as before;
  1239 
  1240 * refined token_translation interface; INCOMPATIBILITY: output length
  1241 now of type real instead of int;
  1242 
  1243 * theory loader actions may be traced via new ThyInfo.add_hook
  1244 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1245 your own database of information attached to *whole* theories -- as
  1246 opposed to intra-theory data slots offered via TheoryDataFun;
  1247 
  1248 * proper handling of dangling sort hypotheses (at last!);
  1249 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1250 extra sort hypotheses that can be witnessed from the type signature;
  1251 the force_strip_shyps flag is gone, any remaining shyps are simply
  1252 left in the theorem (with a warning issued by strip_shyps_warning);
  1253 
  1254 
  1255 
  1256 New in Isabelle98-1 (October 1998)
  1257 ----------------------------------
  1258 
  1259 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1260 
  1261 * several changes of automated proof tools;
  1262 
  1263 * HOL: major changes to the inductive and datatype packages, including
  1264 some minor incompatibilities of theory syntax;
  1265 
  1266 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1267 called `inj_on';
  1268 
  1269 * HOL: removed duplicate thms in Arith:
  1270   less_imp_add_less  should be replaced by  trans_less_add1
  1271   le_imp_add_le      should be replaced by  trans_le_add1
  1272 
  1273 * HOL: unary minus is now overloaded (new type constraints may be
  1274 required);
  1275 
  1276 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1277 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1278 now taken as an integer constant.
  1279 
  1280 * Pure: ML function 'theory_of' renamed to 'theory';
  1281 
  1282 
  1283 *** Proof tools ***
  1284 
  1285 * Simplifier:
  1286   1. Asm_full_simp_tac is now more aggressive.
  1287      1. It will sometimes reorient premises if that increases their power to
  1288         simplify.
  1289      2. It does no longer proceed strictly from left to right but may also
  1290         rotate premises to achieve further simplification.
  1291      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1292      old Asm_full_simp_tac in that it does not rotate premises.
  1293   2. The simplifier now knows a little bit about nat-arithmetic.
  1294 
  1295 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1296 allows for selected deletion of wrappers, by introduction of names for
  1297 wrapper functionals.  This implies that addbefore, addSbefore,
  1298 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1299 and that adding two tactics with the same name overwrites the first
  1300 one (emitting a warning).
  1301   type wrapper = (int -> tactic) -> (int -> tactic)
  1302   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1303   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1304   delWrapper, delSWrapper: claset *  string            -> claset
  1305   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1306 
  1307 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1308 semantics; addbefore now affects only the unsafe part of step_tac
  1309 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1310 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1311 by Force_tac;
  1312 
  1313 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1314 compWrapper; added safe wrapper (and access functions for it);
  1315 
  1316 * HOL/split_all_tac is now much faster and fails if there is nothing
  1317 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1318 and the names of the automatically generated variables have changed.
  1319 split_all_tac has moved within claset() from unsafe wrappers to safe
  1320 wrappers, which means that !!-bound variables are split much more
  1321 aggressively, and safe_tac and clarify_tac now split such variables.
  1322 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1323 Note: the same holds for record_split_tac, which does the job of
  1324 split_all_tac for record fields.
  1325 
  1326 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1327 permanently to the default simpset using Addsplits just like
  1328 Addsimps. They can be removed via Delsplits just like
  1329 Delsimps. Lower-case versions are also available.
  1330 
  1331 * HOL/Simplifier: The rule split_if is now part of the default
  1332 simpset. This means that the simplifier will eliminate all occurrences
  1333 of if-then-else in the conclusion of a goal. To prevent this, you can
  1334 either remove split_if completely from the default simpset by
  1335 `Delsplits [split_if]' or remove it in a specific call of the
  1336 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1337 other case splitting rules to/from the default simpset: every datatype
  1338 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1339 t is the name of the datatype).
  1340 
  1341 * Classical reasoner / Simplifier combination: new force_tac (and
  1342 derivatives Force_tac, force) combines rewriting and classical
  1343 reasoning (and whatever other tools) similarly to auto_tac, but is
  1344 aimed to solve the given subgoal completely.
  1345 
  1346 
  1347 *** General ***
  1348 
  1349 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1350 and `goalw': the theory is no longer needed as an explicit argument -
  1351 the current theory context is used; assumptions are no longer returned
  1352 at the ML-level unless one of them starts with ==> or !!; it is
  1353 recommended to convert to these new commands using isatool fixgoal
  1354 (backup your sources first!);
  1355 
  1356 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1357 the current theory context, and 'theory' to lookup stored theories;
  1358 
  1359 * new theory section 'locale' for declaring constants, assumptions and
  1360 definitions that have local scope;
  1361 
  1362 * new theory section 'nonterminals' for purely syntactic types;
  1363 
  1364 * new theory section 'setup' for generic ML setup functions
  1365 (e.g. package initialization);
  1366 
  1367 * the distribution now includes Isabelle icons: see
  1368 lib/logo/isabelle-{small,tiny}.xpm;
  1369 
  1370 * isatool install - install binaries with absolute references to
  1371 ISABELLE_HOME/bin;
  1372 
  1373 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1374 
  1375 * print mode 'emacs' reserved for Isamode;
  1376 
  1377 * support multiple print (ast) translations per constant name;
  1378 
  1379 * theorems involving oracles are now printed with a suffixed [!];
  1380 
  1381 
  1382 *** HOL ***
  1383 
  1384 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1385 
  1386 * HOL/inductive package reorganized and improved: now supports mutual
  1387 definitions such as
  1388 
  1389   inductive EVEN ODD
  1390     intrs
  1391       null "0 : EVEN"
  1392       oddI "n : EVEN ==> Suc n : ODD"
  1393       evenI "n : ODD ==> Suc n : EVEN"
  1394 
  1395 new theorem list "elims" contains an elimination rule for each of the
  1396 recursive sets; inductive definitions now handle disjunctive premises
  1397 correctly (also ZF);
  1398 
  1399 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1400 "mutual_induct" no longer exists - the induction rule is always
  1401 contained in "induct";
  1402 
  1403 
  1404 * HOL/datatype package re-implemented and greatly improved: now
  1405 supports mutually recursive datatypes such as
  1406 
  1407   datatype
  1408     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1409             | SUM ('a aexp) ('a aexp)
  1410             | DIFF ('a aexp) ('a aexp)
  1411             | NUM 'a
  1412   and
  1413     'a bexp = LESS ('a aexp) ('a aexp)
  1414             | AND ('a bexp) ('a bexp)
  1415             | OR ('a bexp) ('a bexp)
  1416 
  1417 as well as indirectly recursive datatypes such as
  1418 
  1419   datatype
  1420     ('a, 'b) term = Var 'a
  1421                   | App 'b ((('a, 'b) term) list)
  1422 
  1423 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1424 induction on mutually / indirectly recursive datatypes.
  1425 
  1426 Primrec equations are now stored in theory and can be accessed via
  1427 <function_name>.simps.
  1428 
  1429 INCOMPATIBILITIES:
  1430 
  1431   - Theories using datatypes must now have theory Datatype as an
  1432     ancestor.
  1433   - The specific <typename>.induct_tac no longer exists - use the
  1434     generic induct_tac instead.
  1435   - natE has been renamed to nat.exhaust - use exhaust_tac
  1436     instead of res_inst_tac ... natE. Note that the variable
  1437     names in nat.exhaust differ from the names in natE, this
  1438     may cause some "fragile" proofs to fail.
  1439   - The theorems split_<typename>_case and split_<typename>_case_asm
  1440     have been renamed to <typename>.split and <typename>.split_asm.
  1441   - Since default sorts of type variables are now handled correctly,
  1442     some datatype definitions may have to be annotated with explicit
  1443     sort constraints.
  1444   - Primrec definitions no longer require function name and type
  1445     of recursive argument.
  1446 
  1447 Consider using isatool fixdatatype to adapt your theories and proof
  1448 scripts to the new package (backup your sources first!).
  1449 
  1450 
  1451 * HOL/record package: considerably improved implementation; now
  1452 includes concrete syntax for record types, terms, updates; theorems
  1453 for surjective pairing and splitting !!-bound record variables; proof
  1454 support is as follows:
  1455 
  1456   1) standard conversions (selectors or updates applied to record
  1457 constructor terms) are part of the standard simpset;
  1458 
  1459   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1460 made part of standard simpset and claset via addIffs;
  1461 
  1462   3) a tactic for record field splitting (record_split_tac) is part of
  1463 the standard claset (addSWrapper);
  1464 
  1465 To get a better idea about these rules you may retrieve them via
  1466 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1467 the name of your record type.
  1468 
  1469 The split tactic 3) conceptually simplifies by the following rule:
  1470 
  1471   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1472 
  1473 Thus any record variable that is bound by meta-all will automatically
  1474 blow up into some record constructor term, consequently the
  1475 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1476 solve record problems automatically.
  1477 
  1478 
  1479 * reorganized the main HOL image: HOL/Integ and String loaded by
  1480 default; theory Main includes everything;
  1481 
  1482 * automatic simplification of integer sums and comparisons, using cancellation;
  1483 
  1484 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1485 
  1486 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1487 
  1488 * many new identities for unions, intersections, set difference, etc.;
  1489 
  1490 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1491 called split_if, split_split, split_sum_case and split_nat_case (to go
  1492 with add/delsplits);
  1493 
  1494 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1495 (?x::unit) = (); this is made part of the default simpset, which COULD
  1496 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1497 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1498 unit_abs_eta_conv is added in order to counter the effect of
  1499 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1500 %u.f();
  1501 
  1502 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1503 makes more sense);
  1504 
  1505 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1506   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1507   disjointness reasoning but breaking a few old proofs.
  1508 
  1509 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1510 to 'converse' from 'inverse' (for compatibility with ZF and some
  1511 literature);
  1512 
  1513 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1514 the well-founded relation;
  1515 
  1516 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1517     Compl A.  The "Compl" syntax remains available as input syntax for this
  1518     release ONLY.
  1519 
  1520 * HOL/Update: new theory of function updates:
  1521     f(a:=b) == %x. if x=a then b else f x
  1522 may also be iterated as in f(a:=b,c:=d,...);
  1523 
  1524 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1525 
  1526 * HOL/List:
  1527   - new function list_update written xs[i:=v] that updates the i-th
  1528     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1529   - new function `upt' written [i..j(] which generates the list
  1530     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1531     bound write [i..j], which is a shorthand for [i..j+1(].
  1532   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1533 
  1534 * HOL/Arith:
  1535   - removed 'pred' (predecessor) function;
  1536   - generalized some theorems about n-1;
  1537   - many new laws about "div" and "mod";
  1538   - new laws about greatest common divisors (see theory ex/Primes);
  1539 
  1540 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1541 instead of "inverse";
  1542 
  1543 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1544   of the multiset ordering;
  1545 
  1546 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1547   (not included by default);
  1548 
  1549 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1550 
  1551 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1552   programs, i.e. different program variables may have different types.
  1553 
  1554 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1555   [previously, this check worked only if the rewrite rule was unconditional]
  1556   Now rew can involve either definitions or equalities (either == or =).
  1557 
  1558 
  1559 *** ZF ***
  1560 
  1561 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1562   only the theorems proved on ZF.ML;
  1563 
  1564 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1565   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1566   disjointness reasoning but breaking a few old proofs.
  1567 
  1568 * ZF/Update: new theory of function updates
  1569     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1570   may also be iterated as in f(a:=b,c:=d,...);
  1571 
  1572 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1573 
  1574 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1575   [previously, this check worked only if the rewrite rule was unconditional]
  1576   Now rew can involve either definitions or equalities (either == or =).
  1577 
  1578 * case_tac provided for compatibility with HOL
  1579     (like the old excluded_middle_tac, but with subgoals swapped)
  1580 
  1581 
  1582 *** Internal programming interfaces ***
  1583 
  1584 * Pure: several new basic modules made available for general use, see
  1585 also src/Pure/README;
  1586 
  1587 * improved the theory data mechanism to support encapsulation (data
  1588 kind name replaced by private Object.kind, acting as authorization
  1589 key); new type-safe user interface via functor TheoryDataFun; generic
  1590 print_data function becomes basically useless;
  1591 
  1592 * removed global_names compatibility flag -- all theory declarations
  1593 are qualified by default;
  1594 
  1595 * module Pure/Syntax now offers quote / antiquote translation
  1596 functions (useful for Hoare logic etc. with implicit dependencies);
  1597 see HOL/ex/Antiquote for an example use;
  1598 
  1599 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1600 cterm -> thm;
  1601 
  1602 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1603 subgoal;
  1604 
  1605 * Display.print_goals function moved to Locale.print_goals;
  1606 
  1607 * standard print function for goals supports current_goals_markers
  1608 variable for marking begin of proof, end of proof, start of goal; the
  1609 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1610 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1611 for example;
  1612 
  1613 
  1614 
  1615 New in Isabelle98 (January 1998)
  1616 --------------------------------
  1617 
  1618 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1619 
  1620 * changed lexical syntax of terms / types: dots made part of long
  1621 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1622 
  1623 * simpset (and claset) reference variable replaced by functions
  1624 simpset / simpset_ref;
  1625 
  1626 * no longer supports theory aliases (via merge) and non-trivial
  1627 implicit merge of thms' signatures;
  1628 
  1629 * most internal names of constants changed due to qualified names;
  1630 
  1631 * changed Pure/Sequence interface (see Pure/seq.ML);
  1632 
  1633 
  1634 *** General Changes ***
  1635 
  1636 * hierachically structured name spaces (for consts, types, axms, thms
  1637 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1638 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1639 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1640 long_names for fully qualified output names; NOTE: ML programs
  1641 (special tactics, packages etc.) referring to internal names may have
  1642 to be adapted to cope with fully qualified names; in case of severe
  1643 backward campatibility problems try setting 'global_names' at compile
  1644 time to have enrything declared within a flat name space; one may also
  1645 fine tune name declarations in theories via the 'global' and 'local'
  1646 section;
  1647 
  1648 * reimplemented the implicit simpset and claset using the new anytype
  1649 data filed in signatures; references simpset:simpset ref etc. are
  1650 replaced by functions simpset:unit->simpset and
  1651 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1652 to patch your ML files accordingly;
  1653 
  1654 * HTML output now includes theory graph data for display with Java
  1655 applet or isatool browser; data generated automatically via isatool
  1656 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1657 
  1658 * defs may now be conditional; improved rewrite_goals_tac to handle
  1659 conditional equations;
  1660 
  1661 * defs now admits additional type arguments, using TYPE('a) syntax;
  1662 
  1663 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1664 creates a new theory node; implicit merge of thms' signatures is
  1665 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1666 transfer:theory->thm->thm in (rare) cases;
  1667 
  1668 * improved handling of draft signatures / theories; draft thms (and
  1669 ctyps, cterms) are automatically promoted to real ones;
  1670 
  1671 * slightly changed interfaces for oracles: admit many per theory, named
  1672 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1673 
  1674 * print_goals: optional output of const types (set show_consts and
  1675 show_types);
  1676 
  1677 * improved output of warnings (###) and errors (***);
  1678 
  1679 * subgoal_tac displays a warning if the new subgoal has type variables;
  1680 
  1681 * removed old README and Makefiles;
  1682 
  1683 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1684 
  1685 * removed obsolete init_pps and init_database;
  1686 
  1687 * deleted the obsolete tactical STATE, which was declared by
  1688     fun STATE tacfun st = tacfun st st;
  1689 
  1690 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1691 (which abbreviates $HOME);
  1692 
  1693 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1694 use isatool fixseq to adapt your ML programs (this works for fully
  1695 qualified references to the Sequence structure only!);
  1696 
  1697 * use_thy no longer requires writable current directory; it always
  1698 reloads .ML *and* .thy file, if either one is out of date;
  1699 
  1700 
  1701 *** Classical Reasoner ***
  1702 
  1703 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1704 tactics that use classical reasoning to simplify a subgoal without
  1705 splitting it into several subgoals;
  1706 
  1707 * Safe_tac: like safe_tac but uses the default claset;
  1708 
  1709 
  1710 *** Simplifier ***
  1711 
  1712 * added simplification meta rules:
  1713     (asm_)(full_)simplify: simpset -> thm -> thm;
  1714 
  1715 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1716 logics (again);
  1717 
  1718 * added prems argument to simplification procedures;
  1719 
  1720 * HOL, FOL, ZF: added infix function `addsplits':
  1721   instead of `<simpset> setloop (split_tac <thms>)'
  1722   you can simply write `<simpset> addsplits <thms>'
  1723 
  1724 
  1725 *** Syntax ***
  1726 
  1727 * TYPE('a) syntax for type reflection terms;
  1728 
  1729 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1730 
  1731 * pretty printer: changed order of mixfix annotation preference (again!);
  1732 
  1733 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1734 
  1735 
  1736 *** HOL ***
  1737 
  1738 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1739   with `addloop' of the simplifier to faciliate case splitting in premises.
  1740 
  1741 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1742 
  1743 * HOL/Auth: new protocol proofs including some for the Internet
  1744   protocol TLS;
  1745 
  1746 * HOL/Map: new theory of `maps' a la VDM;
  1747 
  1748 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1749 cancelling out common nat summands from =, <, <= (in)equalities, or
  1750 differences; simplification procedures nat_cancel_factor for
  1751 cancelling common factor from =, <, <= (in)equalities over natural
  1752 sums; nat_cancel contains both kinds of procedures, it is installed by
  1753 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1754 
  1755 * HOL/simplifier: terms of the form
  1756   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1757   are rewritten to
  1758   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1759   and those of the form
  1760   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1761   are rewritten to
  1762   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1763 
  1764 * HOL/datatype
  1765   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1766 
  1767   P(t_case f1 ... fn x) =
  1768      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1769         ...
  1770        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1771      )
  1772 
  1773   and a theorem `split_t_case_asm' of the form
  1774 
  1775   P(t_case f1 ... fn x) =
  1776     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1777         ...
  1778        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1779      )
  1780   which can be added to a simpset via `addsplits'. The existing theorems
  1781   expand_list_case and expand_option_case have been renamed to
  1782   split_list_case and split_option_case.
  1783 
  1784 * HOL/Arithmetic:
  1785   - `pred n' is automatically converted to `n-1'.
  1786     Users are strongly encouraged not to use `pred' any longer,
  1787     because it will disappear altogether at some point.
  1788   - Users are strongly encouraged to write "0 < n" rather than
  1789     "n ~= 0". Theorems and proof tools have been modified towards this
  1790     `standard'.
  1791 
  1792 * HOL/Lists:
  1793   the function "set_of_list" has been renamed "set" (and its theorems too);
  1794   the function "nth" now takes its arguments in the reverse order and
  1795   has acquired the infix notation "!" as in "xs!n".
  1796 
  1797 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1798 
  1799 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1800   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1801 
  1802 * HOL/record: extensible records with schematic structural subtyping
  1803 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1804 still lacks various theorems and concrete record syntax;
  1805 
  1806 
  1807 *** HOLCF ***
  1808 
  1809 * removed "axioms" and "generated by" sections;
  1810 
  1811 * replaced "ops" section by extended "consts" section, which is capable of
  1812   handling the continuous function space "->" directly;
  1813 
  1814 * domain package:
  1815   . proves theorems immediately and stores them in the theory,
  1816   . creates hierachical name space,
  1817   . now uses normal mixfix annotations (instead of cinfix...),
  1818   . minor changes to some names and values (for consistency),
  1819   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1820   . separator between mutual domain defs: changed "," to "and",
  1821   . improved handling of sort constraints;  now they have to
  1822     appear on the left-hand side of the equations only;
  1823 
  1824 * fixed LAM <x,y,zs>.b syntax;
  1825 
  1826 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1827 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1828 
  1829 
  1830 *** FOL and ZF ***
  1831 
  1832 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1833   with `addloop' of the simplifier to faciliate case splitting in premises.
  1834 
  1835 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1836 in HOL, they strip ALL and --> from proved theorems;
  1837 
  1838 
  1839 
  1840 New in Isabelle94-8 (May 1997)
  1841 ------------------------------
  1842 
  1843 *** General Changes ***
  1844 
  1845 * new utilities to build / run / maintain Isabelle etc. (in parts
  1846 still somewhat experimental); old Makefiles etc. still functional;
  1847 
  1848 * new 'Isabelle System Manual';
  1849 
  1850 * INSTALL text, together with ./configure and ./build scripts;
  1851 
  1852 * reimplemented type inference for greater efficiency, better error
  1853 messages and clean internal interface;
  1854 
  1855 * prlim command for dealing with lots of subgoals (an easier way of
  1856 setting goals_limit);
  1857 
  1858 
  1859 *** Syntax ***
  1860 
  1861 * supports alternative (named) syntax tables (parser and pretty
  1862 printer); internal interface is provided by add_modesyntax(_i);
  1863 
  1864 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1865 be used in conjunction with the Isabelle symbol font; uses the
  1866 "symbols" syntax table;
  1867 
  1868 * added token_translation interface (may translate name tokens in
  1869 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1870 the current print_mode); IMPORTANT: user print translation functions
  1871 are responsible for marking newly introduced bounds
  1872 (Syntax.mark_boundT);
  1873 
  1874 * token translations for modes "xterm" and "xterm_color" that display
  1875 names in bold, underline etc. or colors (which requires a color
  1876 version of xterm);
  1877 
  1878 * infixes may now be declared with names independent of their syntax;
  1879 
  1880 * added typed_print_translation (like print_translation, but may
  1881 access type of constant);
  1882 
  1883 
  1884 *** Classical Reasoner ***
  1885 
  1886 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1887 some limitations.  Blast_tac...
  1888   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1889   + ignores elimination rules that don't have the correct format
  1890         (the conclusion MUST be a formula variable)
  1891   + ignores types, which can make HOL proofs fail
  1892   + rules must not require higher-order unification, e.g. apply_type in ZF
  1893     [message "Function Var's argument not a bound variable" relates to this]
  1894   + its proof strategy is more general but can actually be slower
  1895 
  1896 * substitution with equality assumptions no longer permutes other
  1897 assumptions;
  1898 
  1899 * minor changes in semantics of addafter (now called addaltern); renamed
  1900 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1901 (and access functions for it);
  1902 
  1903 * improved combination of classical reasoner and simplifier:
  1904   + functions for handling clasimpsets
  1905   + improvement of addss: now the simplifier is called _after_ the
  1906     safe steps.
  1907   + safe variant of addss called addSss: uses safe simplifications
  1908     _during_ the safe steps. It is more complete as it allows multiple
  1909     instantiations of unknowns (e.g. with slow_tac).
  1910 
  1911 *** Simplifier ***
  1912 
  1913 * added interface for simplification procedures (functions that
  1914 produce *proven* rewrite rules on the fly, depending on current
  1915 redex);
  1916 
  1917 * ordering on terms as parameter (used for ordered rewriting);
  1918 
  1919 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1920 
  1921 * the solver is now split into a safe and an unsafe part.
  1922 This should be invisible for the normal user, except that the
  1923 functions setsolver and addsolver have been renamed to setSolver and
  1924 addSolver; added safe_asm_full_simp_tac;
  1925 
  1926 
  1927 *** HOL ***
  1928 
  1929 * a generic induction tactic `induct_tac' which works for all datatypes and
  1930 also for type `nat';
  1931 
  1932 * a generic case distinction tactic `exhaust_tac' which works for all
  1933 datatypes and also for type `nat';
  1934 
  1935 * each datatype comes with a function `size';
  1936 
  1937 * patterns in case expressions allow tuple patterns as arguments to
  1938 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1939 
  1940 * primrec now also works with type nat;
  1941 
  1942 * recdef: a new declaration form, allows general recursive functions to be
  1943 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1944 
  1945 * the constant for negation has been renamed from "not" to "Not" to
  1946 harmonize with FOL, ZF, LK, etc.;
  1947 
  1948 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1949 infinite lists;
  1950 
  1951 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1952 
  1953 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1954 problems in commutative rings, using axiomatic type classes for + and *;
  1955 
  1956 * more examples in HOL/MiniML and HOL/Auth;
  1957 
  1958 * more default rewrite rules for quantifiers, union/intersection;
  1959 
  1960 * a new constant `arbitrary == @x.False';
  1961 
  1962 * HOLCF/IOA replaces old HOL/IOA;
  1963 
  1964 * HOLCF changes: derived all rules and arities
  1965   + axiomatic type classes instead of classes
  1966   + typedef instead of faking type definitions
  1967   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1968   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1969   + eliminated the types void, one, tr
  1970   + use unit lift and bool lift (with translations) instead of one and tr
  1971   + eliminated blift from Lift3.thy (use Def instead of blift)
  1972   all eliminated rules are derived as theorems --> no visible changes ;
  1973 
  1974 
  1975 *** ZF ***
  1976 
  1977 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1978 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1979 as ZF_cs addSIs [equalityI];
  1980 
  1981 
  1982 
  1983 New in Isabelle94-7 (November 96)
  1984 ---------------------------------
  1985 
  1986 * allowing negative levels (as offsets) in prlev and choplev;
  1987 
  1988 * super-linear speedup for large simplifications;
  1989 
  1990 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1991 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1992 FAIL); can suppress it using the command Delsimps (ex_simps @
  1993 all_simps); De Morgan laws are also now included, by default;
  1994 
  1995 * improved printing of ==>  :  ~:
  1996 
  1997 * new object-logic "Sequents" adds linear logic, while replacing LK
  1998 and Modal (thanks to Sara Kalvala);
  1999 
  2000 * HOL/Auth: correctness proofs for authentication protocols;
  2001 
  2002 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2003 examples on HOL/Auth);
  2004 
  2005 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2006 the rewriter and classical reasoner simultaneously;
  2007 
  2008 * function uresult no longer returns theorems in "standard" format;
  2009 regain previous version by: val uresult = standard o uresult;
  2010 
  2011 
  2012 
  2013 New in Isabelle94-6
  2014 -------------------
  2015 
  2016 * oracles -- these establish an interface between Isabelle and trusted
  2017 external reasoners, which may deliver results as theorems;
  2018 
  2019 * proof objects (in particular record all uses of oracles);
  2020 
  2021 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2022 
  2023 * "constdefs" section in theory files;
  2024 
  2025 * "primrec" section (HOL) no longer requires names;
  2026 
  2027 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2028 
  2029 
  2030 
  2031 New in Isabelle94-5
  2032 -------------------
  2033 
  2034 * reduced space requirements;
  2035 
  2036 * automatic HTML generation from theories;
  2037 
  2038 * theory files no longer require "..." (quotes) around most types;
  2039 
  2040 * new examples, including two proofs of the Church-Rosser theorem;
  2041 
  2042 * non-curried (1994) version of HOL is no longer distributed;
  2043 
  2044 
  2045 
  2046 New in Isabelle94-4
  2047 -------------------
  2048 
  2049 * greatly reduced space requirements;
  2050 
  2051 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2052 
  2053 * searchable theorem database (see the section "Retrieving theorems" on
  2054 page 8 of the Reference Manual);
  2055 
  2056 * new examples, including Grabczewski's monumental case study of the
  2057 Axiom of Choice;
  2058 
  2059 * The previous version of HOL renamed to Old_HOL;
  2060 
  2061 * The new version of HOL (previously called CHOL) uses a curried syntax
  2062 for functions.  Application looks like f a b instead of f(a,b);
  2063 
  2064 * Mutually recursive inductive definitions finally work in HOL;
  2065 
  2066 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2067 translates to the operator "split";
  2068 
  2069 
  2070 
  2071 New in Isabelle94-3
  2072 -------------------
  2073 
  2074 * new infix operator, addss, allowing the classical reasoner to
  2075 perform simplification at each step of its search.  Example:
  2076         fast_tac (cs addss ss)
  2077 
  2078 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2079 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2080 look like (a,b) instead of <a,b>;
  2081 
  2082 * PLEASE NOTE: CHOL will eventually replace HOL!
  2083 
  2084 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2085 It translates to the operator "split".  A new theory of integers is available;
  2086 
  2087 * In ZF, integer numerals now denote two's-complement binary integers.
  2088 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2089 
  2090 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2091 of the Axiom of Choice;
  2092 
  2093 
  2094 
  2095 New in Isabelle94-2
  2096 -------------------
  2097 
  2098 * Significantly faster resolution;
  2099 
  2100 * the different sections in a .thy file can now be mixed and repeated
  2101 freely;
  2102 
  2103 * Database of theorems for FOL, HOL and ZF.  New
  2104 commands including qed, qed_goal and bind_thm store theorems in the database.
  2105 
  2106 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2107 a given theory (thms_of), or find out what theory a theorem was proved in
  2108 (theory_of_thm);
  2109 
  2110 * Bugs fixed in the inductive definition and datatype packages;
  2111 
  2112 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2113 and HOL_dup_cs obsolete;
  2114 
  2115 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2116 have been removed;
  2117 
  2118 * Simpler definition of function space in ZF;
  2119 
  2120 * new results about cardinal and ordinal arithmetic in ZF;
  2121 
  2122 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2123 types;
  2124 
  2125 
  2126 $Id$