NEWS
author wenzelm
Fri Dec 21 23:16:17 2001 +0100 (2001-12-21)
changeset 12587 3f3d2ffb5df5
parent 12564 226873bffa3a
child 12597 14822e4436bf
permissions -rw-r--r--
HOL/record: shared operations ("more", "fields", etc.) now need to be
always qualified;
     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   - shared operations ("more", "fields", etc.) now need to be always
   194     qualified) --- potential INCOMPATIBILITY;
   195   - removed "make_scheme" operations (use "make" with "extend") --
   196     INCOMPATIBILITY;
   197   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   198   - provides cases/induct rules for use with corresponding Isar
   199     methods (for concrete records, record schemes, concrete more
   200     parts, and schematic more parts -- in that order);
   201   - internal definitions directly based on a light-weight abstract
   202     theory of product types over typedef rather than datatype;
   203 
   204 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   205 
   206 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   207 (beware of argument permutation!);
   208 
   209 * HOL: linorder_less_split superseded by linorder_cases;
   210 
   211 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   212 to peripheral theory "Hilbert_Choice";
   213 
   214 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   215 in this (rare) case use:
   216 
   217   delSWrapper "split_all_tac"
   218   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   219 
   220 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   221 MAY FAIL;
   222 
   223 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   224 Isabelle's type classes, ^ on functions and relations has too general
   225 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   226 necessary to attach explicit type constraints;
   227 
   228 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   229 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   230 (eg "compI" -> "rel_compI").
   231 
   232 * HOL: syntax translations now work properly with numerals and records
   233 expressions;
   234 
   235 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   236 of "lam" -- INCOMPATIBILITY;
   237 
   238 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   239 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   240 renamed "Product_Type.unit";
   241 
   242 * HOL/GroupTheory: group theory examples including Sylow's theorem, by
   243 Florian Kammüller;
   244 
   245 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   246 
   247 
   248 *** HOLCF ***
   249 
   250 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
   251 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   252 lift.induct_tac, always use UU instead of Undef;
   253 
   254 
   255 *** ZF ***
   256 
   257 * Theory Main no longer includes AC; for the Axiom of Choice, base your 
   258 theory on Main_ZFC;
   259 
   260 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   261 typeless version of the formalism;
   262 
   263 * ZF/Induct: new directory for examples of inductive definitions,
   264 including theory Multiset for multiset orderings;
   265 
   266 * ZF: the integer library now covers quotients and remainders, with
   267 many laws relating division to addition, multiplication, etc.;
   268 
   269 
   270 *** General ***
   271 
   272 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   273 variable proof controls level of detail: 0 = no proofs (only oracle
   274 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   275 also ref manual for further ML interfaces;
   276 
   277 * Pure/axclass: removed obsolete ML interface
   278 goal_subclass/goal_arity;
   279 
   280 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   281 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   282 separate tokens, so expressions involving minus need to be spaced
   283 properly;
   284 
   285 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   286 rather than "infixl" or "infixr";
   287 
   288 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   289 sort constraint specifications in type inference; e.g. "x::_::foo"
   290 ensures that the type of "x" is of sort "foo" (but not necessarily a
   291 type variable);
   292 
   293 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   294 control output of nested => (types); the default behavior is
   295 "type_brackets";
   296 
   297 * Pure/syntax: builtin parse translation for "_constify" turns valued
   298 tokens into AST constants;
   299 
   300 * Pure/syntax: prefer later declarations of translations and print
   301 translation functions; potential INCOMPATIBILITY: need to reverse
   302 multiple declarations for same syntax element constant;
   303 
   304 * Provers/classical: renamed addaltern to addafter, addSaltern to
   305 addSafter;
   306 
   307 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   308 as well;
   309 
   310 * system: tested support for MacOS X; should be able to get Isabelle +
   311 Proof General to work in a plain Terminal after installing Poly/ML
   312 (e.g. from the Isabelle distribution area) and GNU bash alone
   313 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   314 support requires further installations, e.g. from
   315 http://fink.sourceforge.net/);
   316 
   317 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   318 
   319 * system: Proof General keywords specification is now part of the
   320 Isabelle distribution (see etc/isar-keywords.el);
   321 
   322 * system: smart selection of Isabelle process versus Isabelle
   323 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   324 run both "isabelle" and "Isabelle" even if file names are badly
   325 damaged (executable inspects the case of the first letter of its own
   326 name); added separate "isabelle-process" and "isabelle-interface";
   327 
   328 * system: refrain from any attempt at filtering input streams; no
   329 longer support ``8bit'' encoding of old isabelle font, instead proper
   330 iso-latin characters may now be used; the related isatools
   331 "symbolinput" and "nonascii" have disappeared as well;
   332 
   333 * system: removed old "xterm" interface (the print modes "xterm" and
   334 "xterm_color" are still available for direct use in a suitable
   335 terminal);
   336 
   337 
   338 
   339 New in Isabelle99-2 (February 2001)
   340 -----------------------------------
   341 
   342 *** Overview of INCOMPATIBILITIES ***
   343 
   344 * HOL: please note that theories in the Library and elsewhere often use the
   345 new-style (Isar) format; to refer to their theorems in an ML script you must
   346 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   347 
   348 * HOL: inductive package no longer splits induction rule aggressively,
   349 but only as far as specified by the introductions given; the old
   350 format may be recovered via ML function complete_split_rule or attribute
   351 'split_rule (complete)';
   352 
   353 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   354 gfp_Tarski to gfp_unfold;
   355 
   356 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   357 
   358 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   359 relation); infix "^^" has been renamed "``"; infix "``" has been
   360 renamed "`"; "univalent" has been renamed "single_valued";
   361 
   362 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   363 operation;
   364 
   365 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   366 
   367 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   368 
   369 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   370 consequence, it is no longer monotonic wrt. the local goal context
   371 (which is now passed through the inductive cases);
   372 
   373 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   374 \<gg> to \<ggreater>;
   375 
   376 
   377 *** Document preparation ***
   378 
   379 * \isabellestyle{NAME} selects version of Isabelle output (currently
   380 available: are "it" for near math-mode best-style output, "sl" for
   381 slanted text style, and "tt" for plain type-writer; if no
   382 \isabellestyle command is given, output is according to slanted
   383 type-writer);
   384 
   385 * support sub/super scripts (for single symbols only), input syntax is
   386 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   387 
   388 * some more standard symbols; see Appendix A of the system manual for
   389 the complete list of symbols defined in isabellesym.sty;
   390 
   391 * improved isabelle style files; more abstract symbol implementation
   392 (should now use \isamath{...} and \isatext{...} in custom symbol
   393 definitions);
   394 
   395 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   396 state; Note that presentation of goal states does not conform to
   397 actual human-readable proof documents.  Please do not include goal
   398 states into document output unless you really know what you are doing!
   399 
   400 * proper indentation of antiquoted output with proportional LaTeX
   401 fonts;
   402 
   403 * no_document ML operator temporarily disables LaTeX document
   404 generation;
   405 
   406 * isatool unsymbolize tunes sources for plain ASCII communication;
   407 
   408 
   409 *** Isar ***
   410 
   411 * Pure: Isar now suffers initial goal statements to contain unbound
   412 schematic variables (this does not conform to actual readable proof
   413 documents, due to unpredictable outcome and non-compositional proof
   414 checking); users who know what they are doing may use schematic goals
   415 for Prolog-style synthesis of proven results;
   416 
   417 * Pure: assumption method (an implicit finishing) now handles actual
   418 rules as well;
   419 
   420 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   421 initial goal, declare "that" only as Pure intro (only for single
   422 steps); the "that" rule assumption may now be involved in implicit
   423 finishing, thus ".." becomes a feasible for trivial obtains;
   424 
   425 * Pure: default proof step now includes 'intro_classes'; thus trivial
   426 instance proofs may be performed by "..";
   427 
   428 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   429 statements as well;
   430 
   431 * Pure: more robust selection of calculational rules;
   432 
   433 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   434 rule (as well as the assumption rule);
   435 
   436 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   437 lemmas, using the graph browser tool;
   438 
   439 * Pure: predict failure of "show" in interactive mode;
   440 
   441 * Pure: 'thms_containing' now takes actual terms as arguments;
   442 
   443 * HOL: improved method 'induct' --- now handles non-atomic goals
   444 (potential INCOMPATIBILITY); tuned error handling;
   445 
   446 * HOL: cases and induct rules now provide explicit hints about the
   447 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   448 any remaining facts are inserted into the goal verbatim;
   449 
   450 * HOL: local contexts (aka cases) may now contain term bindings as
   451 well; the 'cases' and 'induct' methods new provide a ?case binding for
   452 the result to be shown in each case;
   453 
   454 * HOL: added 'recdef_tc' command;
   455 
   456 * isatool convert assists in eliminating legacy ML scripts;
   457 
   458 
   459 *** HOL ***
   460 
   461 * HOL/Library: a collection of generic theories to be used together
   462 with main HOL; the theory loader path already includes this directory
   463 by default; the following existing theories have been moved here:
   464 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   465 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   466 
   467 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   468 modelling and verification task performed in Isabelle/HOL +
   469 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   470 
   471 * HOL/Algebra: special summation operator SUM no longer exists, it has
   472 been replaced by setsum; infix 'assoc' now has priority 50 (like
   473 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   474 'domain', this makes the theory consistent with mathematical
   475 literature;
   476 
   477 * HOL basics: added overloaded operations "inverse" and "divide"
   478 (infix "/"), syntax for generic "abs" operation, generic summation
   479 operator \<Sum>;
   480 
   481 * HOL/typedef: simplified package, provide more useful rules (see also
   482 HOL/subset.thy);
   483 
   484 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   485 now expressed as a proper nested rule (old-style tactic scripts may
   486 require atomize_strip_tac to cope with non-atomic premises);
   487 
   488 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   489 to "split_conv" (old name still available for compatibility);
   490 
   491 * HOL: improved concrete syntax for strings (e.g. allows translation
   492 rules with string literals);
   493 
   494 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   495  and Fleuriot's mechanization of analysis, including the transcendental
   496  functions for the reals;
   497 
   498 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   499 
   500 
   501 *** CTT ***
   502 
   503 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   504 "lam" is displayed as TWO lambda-symbols
   505 
   506 * CTT: theory Main now available, containing everything (that is, Bool
   507 and Arith);
   508 
   509 
   510 *** General ***
   511 
   512 * Pure: the Simplifier has been implemented properly as a derived rule
   513 outside of the actual kernel (at last!); the overall performance
   514 penalty in practical applications is about 50%, while reliability of
   515 the Isabelle inference kernel has been greatly improved;
   516 
   517 * print modes "brackets" and "no_brackets" control output of nested =>
   518 (types) and ==> (props); the default behaviour is "brackets";
   519 
   520 * Provers: fast_tac (and friends) now handle actual object-logic rules
   521 as assumptions as well;
   522 
   523 * system: support Poly/ML 4.0;
   524 
   525 * system: isatool install handles KDE version 1 or 2;
   526 
   527 
   528 
   529 New in Isabelle99-1 (October 2000)
   530 ----------------------------------
   531 
   532 *** Overview of INCOMPATIBILITIES ***
   533 
   534 * HOL: simplification of natural numbers is much changed; to partly
   535 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   536 issue the following ML commands:
   537 
   538   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   539   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   540 
   541 * HOL: simplification no longer dives into case-expressions; this is
   542 controlled by "t.weak_case_cong" for each datatype t;
   543 
   544 * HOL: nat_less_induct renamed to less_induct;
   545 
   546 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   547 fixsome to patch .thy and .ML sources automatically;
   548 
   549   select_equality  -> some_equality
   550   select_eq_Ex     -> some_eq_ex
   551   selectI2EX       -> someI2_ex
   552   selectI2         -> someI2
   553   selectI          -> someI
   554   select1_equality -> some1_equality
   555   Eps_sym_eq       -> some_sym_eq_trivial
   556   Eps_eq           -> some_eq_trivial
   557 
   558 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   559 
   560 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   561 instead);
   562 
   563 * HOL: the recursion equations generated by 'recdef' are now called
   564 f.simps instead of f.rules;
   565 
   566 * HOL: qed_spec_mp now also handles bounded ALL as well;
   567 
   568 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   569 sometimes be needed;
   570 
   571 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   572 
   573 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   574 
   575 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   576 product is now "<*>" instead of "Times"; the lexicographic product is
   577 now "<*lex*>" instead of "**";
   578 
   579 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   580 of main HOL, but was unused); better use HOL's datatype package;
   581 
   582 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   583 the old syntax may be recovered as follows:
   584 
   585   syntax (symbols)
   586     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   587       (infixl "\\<oplus>" 100)
   588 
   589 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   590 
   591 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   592 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   593 internally;
   594 
   595 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   596 changed from A/r to A//r;
   597 
   598 * ZF: new treatment of arithmetic (nat & int) may break some old
   599 proofs;
   600 
   601 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   602 rulify -> rule_format, elimify -> elim_format, ...);
   603 
   604 * Isar/Provers: intro/elim/dest attributes changed; renamed
   605 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   606 should have to change intro!! to intro? only); replaced "delrule" by
   607 "rule del";
   608 
   609 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   610 
   611 * Provers: strengthened force_tac by using new first_best_tac;
   612 
   613 * LaTeX document preparation: several changes of isabelle.sty (see
   614 lib/texinputs);
   615 
   616 
   617 *** Document preparation ***
   618 
   619 * formal comments (text blocks etc.) in new-style theories may now
   620 contain antiquotations of thm/prop/term/typ/text to be presented
   621 according to latex print mode; concrete syntax is like this:
   622 @{term[show_types] "f(x) = a + x"};
   623 
   624 * isatool mkdir provides easy setup of Isabelle session directories,
   625 including proper document sources;
   626 
   627 * generated LaTeX sources are now deleted after successful run
   628 (isatool document -c); may retain a copy somewhere else via -D option
   629 of isatool usedir;
   630 
   631 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   632 style files, achieving self-contained LaTeX sources and simplifying
   633 LaTeX debugging;
   634 
   635 * old-style theories now produce (crude) LaTeX output as well;
   636 
   637 * browser info session directories are now self-contained (may be put
   638 on WWW server seperately); improved graphs of nested sessions; removed
   639 graph for 'all sessions';
   640 
   641 * several improvements in isabelle style files; \isabellestyle{it}
   642 produces fake math mode output; \isamarkupheader is now \section by
   643 default; see lib/texinputs/isabelle.sty etc.;
   644 
   645 
   646 *** Isar ***
   647 
   648 * Isar/Pure: local results and corresponding term bindings are now
   649 subject to Hindley-Milner polymorphism (similar to ML); this
   650 accommodates incremental type-inference very nicely;
   651 
   652 * Isar/Pure: new derived language element 'obtain' supports
   653 generalized existence reasoning;
   654 
   655 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   656 support accumulation of results, without applying any rules yet;
   657 useful to collect intermediate results without explicit name
   658 references, and for use with transitivity rules with more than 2
   659 premises;
   660 
   661 * Isar/Pure: scalable support for case-analysis type proofs: new
   662 'case' language element refers to local contexts symbolically, as
   663 produced by certain proof methods; internally, case names are attached
   664 to theorems as "tags";
   665 
   666 * Isar/Pure: theory command 'hide' removes declarations from
   667 class/type/const name spaces;
   668 
   669 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   670 indicate potential overloading;
   671 
   672 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   673 
   674 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   675 "{a,b,c}" instead of {a,b,c};
   676 
   677 * Isar/Pure now provides its own version of intro/elim/dest
   678 attributes; useful for building new logics, but beware of confusion
   679 with the version in Provers/classical;
   680 
   681 * Isar/Pure: the local context of (non-atomic) goals is provided via
   682 case name 'antecedent';
   683 
   684 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   685 to the current context is now done automatically);
   686 
   687 * Isar/Pure: theory command 'method_setup' provides a simple interface
   688 for definining proof methods in ML;
   689 
   690 * Isar/Provers: intro/elim/dest attributes changed; renamed
   691 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   692 most cases, one should have to change intro!! to intro? only);
   693 replaced "delrule" by "rule del";
   694 
   695 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   696 'symmetric' attribute (the latter supercedes [RS sym]);
   697 
   698 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   699 method modifier); 'simp' method: 'only:' modifier removes loopers as
   700 well (including splits);
   701 
   702 * Isar/Provers: Simplifier and Classical methods now support all kind
   703 of modifiers used in the past, including 'cong', 'iff', etc.
   704 
   705 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   706 of Simplifier and Classical reasoner);
   707 
   708 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   709 now support named cases; major packages (inductive, datatype, primrec,
   710 recdef) support case names and properly name parameters;
   711 
   712 * Isar/HOL: new transitivity rules for substitution in inequalities --
   713 monotonicity conditions are extracted to be proven at end of
   714 calculations;
   715 
   716 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   717 method anyway;
   718 
   719 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   720 split_if split_if_asm; datatype package provides theorems foo.splits =
   721 foo.split foo.split_asm for each datatype;
   722 
   723 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   724 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   725 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   726 use "(cases (simplified))" method in proper proof texts);
   727 
   728 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   729 
   730 * Isar: names of theorems etc. may be natural numbers as well;
   731 
   732 * Isar: 'pr' command: optional arguments for goals_limit and
   733 ProofContext.prems_limit; no longer prints theory contexts, but only
   734 proof states;
   735 
   736 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   737 additional print modes to be specified; e.g. "pr(latex)" will print
   738 proof state according to the Isabelle LaTeX style;
   739 
   740 * Isar: improved support for emulating tactic scripts, including proof
   741 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   742 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   743 (for HOL datatypes);
   744 
   745 * Isar: simplified (more robust) goal selection of proof methods: 1st
   746 goal, all goals, or explicit goal specifier (tactic emulation); thus
   747 'proof method scripts' have to be in depth-first order;
   748 
   749 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   750 
   751 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   752 should instead use individual commands for printing items
   753 (print_commands, print_methods etc.);
   754 
   755 * Isar: added 'nothing' --- the empty list of theorems;
   756 
   757 
   758 *** HOL ***
   759 
   760 * HOL/MicroJava: formalization of a fragment of Java, together with a
   761 corresponding virtual machine and a specification of its bytecode
   762 verifier and a lightweight bytecode verifier, including proofs of
   763 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   764 Cornelia Pusch (see also the homepage of project Bali at
   765 http://isabelle.in.tum.de/Bali/);
   766 
   767 * HOL/Algebra: new theory of rings and univariate polynomials, by
   768 Clemens Ballarin;
   769 
   770 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   771 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   772 Rasmussen;
   773 
   774 * HOL/Lattice: fundamental concepts of lattice theory and order
   775 structures, including duals, properties of bounds versus algebraic
   776 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   777 Theorem for complete lattices etc.; may also serve as a demonstration
   778 for abstract algebraic reasoning using axiomatic type classes, and
   779 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   780 
   781 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   782 von Oheimb;
   783 
   784 * HOL/IMPP: extension of IMP with local variables and mutually
   785 recursive procedures, by David von Oheimb;
   786 
   787 * HOL/Lambda: converted into new-style theory and document;
   788 
   789 * HOL/ex/Multiquote: example of multiple nested quotations and
   790 anti-quotations -- basically a generalized version of de-Bruijn
   791 representation; very useful in avoiding lifting of operations;
   792 
   793 * HOL/record: added general record equality rule to simpset; fixed
   794 select-update simplification procedure to handle extended records as
   795 well; admit "r" as field name;
   796 
   797 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   798 other numeric types and also as the identity of groups, rings, etc.;
   799 
   800 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   801 Types nat and int belong to this axclass;
   802 
   803 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   804    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   805    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   806   two terms #m*u and #n*u are replaced by #(m+n)*u
   807     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   808   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   809     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   810 
   811 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   812 powerful prover for predicate logic but knows nothing of clasets; see
   813 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   814 
   815 * HOL: new version of "case_tac" subsumes both boolean case split and
   816 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   817 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   818 
   819 * HOL: simplification no longer dives into case-expressions: only the
   820 selector expression is simplified, but not the remaining arms; to
   821 enable full simplification of case-expressions for datatype t, you may
   822 remove t.weak_case_cong from the simpset, either globally (Delcongs
   823 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   824 
   825 * HOL/recdef: the recursion equations generated by 'recdef' for
   826 function 'f' are now called f.simps instead of f.rules; if all
   827 termination conditions are proved automatically, these simplification
   828 rules are added to the simpset, as in primrec; rules may be named
   829 individually as well, resulting in a separate list of theorems for
   830 each equation;
   831 
   832 * HOL/While is a new theory that provides a while-combinator. It
   833 permits the definition of tail-recursive functions without the
   834 provision of a termination measure. The latter is necessary once the
   835 invariant proof rule for while is applied.
   836 
   837 * HOL: new (overloaded) notation for the set of elements below/above
   838 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   839 
   840 * HOL: theorems impI, allI, ballI bound as "strip";
   841 
   842 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   843 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   844 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   845 
   846 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   847 
   848 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   849 main HOL, but was unused);
   850 
   851 * HOL: fewer consts declared as global (e.g. have to refer to
   852 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   853 
   854 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   855 in case of overlap with user translations (e.g. judgements over
   856 tuples); (note that the underlying logical represenation is still
   857 bogus);
   858 
   859 
   860 *** ZF ***
   861 
   862 * ZF: simplification automatically cancels common terms in arithmetic
   863 expressions over nat and int;
   864 
   865 * ZF: new treatment of nat to minimize type-checking: all operators
   866 coerce their operands to a natural number using the function natify,
   867 making the algebraic laws unconditional;
   868 
   869 * ZF: as above, for int: operators coerce their operands to an integer
   870 using the function intify;
   871 
   872 * ZF: the integer library now contains many of the usual laws for the
   873 orderings, including $<=, and monotonicity laws for $+ and $*;
   874 
   875 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   876 simplification;
   877 
   878 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   879 to the simplifier and classical reasoner simultaneously;
   880 
   881 
   882 *** General ***
   883 
   884 * Provers: blast_tac now handles actual object-logic rules as
   885 assumptions; note that auto_tac uses blast_tac internally as well;
   886 
   887 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   888 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   889 
   890 * Provers: delrules now handles destruct rules as well (no longer need
   891 explicit make_elim);
   892 
   893 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   894   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   895 use instead the strong form,
   896   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   897 in HOL, FOL and ZF the function cla_make_elim will create such rules
   898 from destruct-rules;
   899 
   900 * Provers: Simplifier.easy_setup provides a fast path to basic
   901 Simplifier setup for new object-logics;
   902 
   903 * Pure: AST translation rules no longer require constant head on LHS;
   904 
   905 * Pure: improved name spaces: ambiguous output is qualified; support
   906 for hiding of names;
   907 
   908 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   909 XSYMBOL_HOME; no longer need to do manual configuration in most
   910 situations;
   911 
   912 * system: compression of ML heaps images may now be controlled via -c
   913 option of isabelle and isatool usedir (currently only observed by
   914 Poly/ML);
   915 
   916 * system: isatool installfonts may handle X-Symbol fonts as well (very
   917 useful for remote X11);
   918 
   919 * system: provide TAGS file for Isabelle sources;
   920 
   921 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   922 order;
   923 
   924 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   925 timing flag supersedes proof_timing and Toplevel.trace;
   926 
   927 * ML: new combinators |>> and |>>> for incremental transformations
   928 with secondary results (e.g. certain theory extensions):
   929 
   930 * ML: PureThy.add_defs gets additional argument to indicate potential
   931 overloading (usually false);
   932 
   933 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   934 results;
   935 
   936 
   937 
   938 New in Isabelle99 (October 1999)
   939 --------------------------------
   940 
   941 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   942 
   943 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   944 are no longer simplified.  (This allows the simplifier to unfold recursive
   945 functional programs.)  To restore the old behaviour, declare
   946 
   947     Delcongs [if_weak_cong];
   948 
   949 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   950 complement;
   951 
   952 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   953 
   954 * HOL/datatype: mutual_induct_tac no longer exists --
   955   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   956 
   957 * HOL/typedef: fixed type inference for representing set; type
   958 arguments now have to occur explicitly on the rhs as type constraints;
   959 
   960 * ZF: The con_defs part of an inductive definition may no longer refer
   961 to constants declared in the same theory;
   962 
   963 * HOL, ZF: the function mk_cases, generated by the inductive
   964 definition package, has lost an argument.  To simplify its result, it
   965 uses the default simpset instead of a supplied list of theorems.
   966 
   967 * HOL/List: the constructors of type list are now Nil and Cons;
   968 
   969 * Simplifier: the type of the infix ML functions
   970         setSSolver addSSolver setSolver addSolver
   971 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   972 for packaging solvers. A solver is created via
   973         mk_solver: string -> (thm list -> int -> tactic) -> solver
   974 where the string argument is only a comment.
   975 
   976 
   977 *** Proof tools ***
   978 
   979 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   980 decision procedure for linear arithmetic. Currently it is used for
   981 types `nat', `int', and `real' in HOL (see below); it can, should and
   982 will be instantiated for other types and logics as well.
   983 
   984 * The simplifier now accepts rewrite rules with flexible heads, eg
   985      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   986   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   987   matching.
   988 
   989 
   990 *** General ***
   991 
   992 * New Isabelle/Isar subsystem provides an alternative to traditional
   993 tactical theorem proving; together with the ProofGeneral/isar user
   994 interface it offers an interactive environment for developing human
   995 readable proof documents (Isar == Intelligible semi-automated
   996 reasoning); for further information see isatool doc isar-ref,
   997 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   998 
   999 * improved and simplified presentation of theories: better HTML markup
  1000 (including colors), graph views in several sizes; isatool usedir now
  1001 provides a proper interface for user theories (via -P option); actual
  1002 document preparation based on (PDF)LaTeX is available as well (for
  1003 new-style theories only); see isatool doc system for more information;
  1004 
  1005 * native support for Proof General, both for classic Isabelle and
  1006 Isabelle/Isar;
  1007 
  1008 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1009 using the graph browser tool;
  1010 
  1011 * Isabelle manuals now also available as PDF;
  1012 
  1013 * theory loader rewritten from scratch (may not be fully
  1014 bug-compatible); old loadpath variable has been replaced by show_path,
  1015 add_path, del_path, reset_path functions; new operations such as
  1016 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1017 isatool doc ref);
  1018 
  1019 * improved isatool install: option -k creates KDE application icon,
  1020 option -p DIR installs standalone binaries;
  1021 
  1022 * added ML_PLATFORM setting (useful for cross-platform installations);
  1023 more robust handling of platform specific ML images for SML/NJ;
  1024 
  1025 * the settings environment is now statically scoped, i.e. it is never
  1026 created again in sub-processes invoked from isabelle, isatool, or
  1027 Isabelle;
  1028 
  1029 * path element specification '~~' refers to '$ISABELLE_HOME';
  1030 
  1031 * in locales, the "assumes" and "defines" parts may be omitted if
  1032 empty;
  1033 
  1034 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1035 long arrows);
  1036 
  1037 * new print_mode "HTML";
  1038 
  1039 * new flag show_tags controls display of tags of theorems (which are
  1040 basically just comments that may be attached by some tools);
  1041 
  1042 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1043 mode and goal output format:
  1044 
  1045 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1046 244c244
  1047 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1048 ---
  1049 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1050 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1051 181c181
  1052 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1053 ---
  1054 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1055 
  1056 * function bind_thms stores lists of theorems (cf. bind_thm);
  1057 
  1058 * new shorthand tactics ftac, eatac, datac, fatac;
  1059 
  1060 * qed (and friends) now accept "" as result name; in that case the
  1061 theorem is not stored, but proper checks and presentation of the
  1062 result still apply;
  1063 
  1064 * theorem database now also indexes constants "Trueprop", "all",
  1065 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1066 
  1067 
  1068 *** HOL ***
  1069 
  1070 ** HOL arithmetic **
  1071 
  1072 * There are now decision procedures for linear arithmetic over nat and
  1073 int:
  1074 
  1075 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1076 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1077 are treated as atomic; subformulae not involving type `nat' or `int'
  1078 are ignored; quantified subformulae are ignored unless they are
  1079 positive universal or negative existential. The tactic has to be
  1080 invoked by hand and can be a little bit slow. In particular, the
  1081 running time is exponential in the number of occurrences of `min' and
  1082 `max', and `-' on `nat'.
  1083 
  1084 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1085 (negated) (in)equalities among the premises and the conclusion into
  1086 account (i.e. no compound formulae) and does not know about `min' and
  1087 `max', and `-' on `nat'. It is fast and is used automatically by the
  1088 simplifier.
  1089 
  1090 NB: At the moment, these decision procedures do not cope with mixed
  1091 nat/int formulae where the two parts interact, such as `m < n ==>
  1092 int(m) < int(n)'.
  1093 
  1094 * HOL/Numeral provides a generic theory of numerals (encoded
  1095 efficiently as bit strings); setup for types nat/int/real is in place;
  1096 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1097 int, existing theories and proof scripts may require a few additional
  1098 type constraints;
  1099 
  1100 * integer division and remainder can now be performed on constant
  1101 arguments;
  1102 
  1103 * many properties of integer multiplication, division and remainder
  1104 are now available;
  1105 
  1106 * An interface to the Stanford Validity Checker (SVC) is available through the
  1107 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1108 are proved automatically.  SVC must be installed separately, and its results
  1109 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1110 invocation of the underlying oracle).  For SVC see
  1111   http://verify.stanford.edu/SVC
  1112 
  1113 * IsaMakefile: the HOL-Real target now builds an actual image;
  1114 
  1115 
  1116 ** HOL misc **
  1117 
  1118 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1119 (in Isabelle/Isar) -- by Gertrud Bauer;
  1120 
  1121 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1122 analysis for assembly languages with subtypes;
  1123 
  1124 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1125 -- avoids syntactic ambiguities and treats state, transition, and
  1126 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1127 changed syntax and (many) tactics;
  1128 
  1129 * HOL/inductive: Now also handles more general introduction rules such
  1130   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1131   theorems are now maintained within the theory (maintained via the
  1132   "mono" attribute);
  1133 
  1134 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1135   (using function types) such as
  1136 
  1137   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1138 
  1139 * HOL/record: record_simproc (part of the default simpset) takes care
  1140 of selectors applied to updated records; record_split_tac is no longer
  1141 part of the default claset; update_defs may now be removed from the
  1142 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1143 
  1144   claset_ref () := claset() addSWrapper record_split_wrapper;
  1145   Delsimprocs [record_simproc]
  1146 
  1147 * HOL/typedef: fixed type inference for representing set; type
  1148 arguments now have to occur explicitly on the rhs as type constraints;
  1149 
  1150 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1151 names rather than an ML expression;
  1152 
  1153 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1154 supplied later.  Program schemes can be defined, such as
  1155     "While B C s = (if B s then While B C (C s) else s)"
  1156 where the well-founded relation can be chosen after B and C have been given.
  1157 
  1158 * HOL/List: the constructors of type list are now Nil and Cons;
  1159 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1160 course, ML tools referring to List.list.op # etc. have to be adapted;
  1161 
  1162 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1163 disabled by default; run isabelle with option -m HOL to get back to
  1164 the original Gordon/HOL-style output;
  1165 
  1166 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1167 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1168 
  1169 * HOL basic syntax simplified (more orthogonal): all variants of
  1170 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1171 Eps operator is provided as well: "SOME x. P[x]";
  1172 
  1173 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1174 
  1175 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1176 thus available for user theories;
  1177 
  1178 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1179 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1180 time;
  1181 
  1182 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1183 several times and then mp;
  1184 
  1185 
  1186 *** LK ***
  1187 
  1188 * the notation <<...>> is now available as a notation for sequences of
  1189 formulas;
  1190 
  1191 * the simplifier is now installed
  1192 
  1193 * the axiom system has been generalized (thanks to Soren Heilmann)
  1194 
  1195 * the classical reasoner now has a default rule database
  1196 
  1197 
  1198 *** ZF ***
  1199 
  1200 * new primrec section allows primitive recursive functions to be given
  1201 directly (as in HOL) over datatypes and the natural numbers;
  1202 
  1203 * new tactics induct_tac and exhaust_tac for induction (or case
  1204 analysis) over datatypes and the natural numbers;
  1205 
  1206 * the datatype declaration of type T now defines the recursor T_rec;
  1207 
  1208 * simplification automatically does freeness reasoning for datatype
  1209 constructors;
  1210 
  1211 * automatic type-inference, with AddTCs command to insert new
  1212 type-checking rules;
  1213 
  1214 * datatype introduction rules are now added as Safe Introduction rules
  1215 to the claset;
  1216 
  1217 * the syntax "if P then x else y" is now available in addition to
  1218 if(P,x,y);
  1219 
  1220 
  1221 *** Internal programming interfaces ***
  1222 
  1223 * tuned simplifier trace output; new flag debug_simp;
  1224 
  1225 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1226 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1227 
  1228 * AxClass.axclass_tac lost the theory argument;
  1229 
  1230 * tuned current_goals_markers semantics: begin / end goal avoids
  1231 printing empty lines;
  1232 
  1233 * removed prs and prs_fn hook, which was broken because it did not
  1234 include \n in its semantics, forcing writeln to add one
  1235 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1236 string -> unit if you really want to output text without newline;
  1237 
  1238 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1239 plain output, interface builders may have to enable 'isabelle_font'
  1240 mode to get Isabelle font glyphs as before;
  1241 
  1242 * refined token_translation interface; INCOMPATIBILITY: output length
  1243 now of type real instead of int;
  1244 
  1245 * theory loader actions may be traced via new ThyInfo.add_hook
  1246 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1247 your own database of information attached to *whole* theories -- as
  1248 opposed to intra-theory data slots offered via TheoryDataFun;
  1249 
  1250 * proper handling of dangling sort hypotheses (at last!);
  1251 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1252 extra sort hypotheses that can be witnessed from the type signature;
  1253 the force_strip_shyps flag is gone, any remaining shyps are simply
  1254 left in the theorem (with a warning issued by strip_shyps_warning);
  1255 
  1256 
  1257 
  1258 New in Isabelle98-1 (October 1998)
  1259 ----------------------------------
  1260 
  1261 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1262 
  1263 * several changes of automated proof tools;
  1264 
  1265 * HOL: major changes to the inductive and datatype packages, including
  1266 some minor incompatibilities of theory syntax;
  1267 
  1268 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1269 called `inj_on';
  1270 
  1271 * HOL: removed duplicate thms in Arith:
  1272   less_imp_add_less  should be replaced by  trans_less_add1
  1273   le_imp_add_le      should be replaced by  trans_le_add1
  1274 
  1275 * HOL: unary minus is now overloaded (new type constraints may be
  1276 required);
  1277 
  1278 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1279 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1280 now taken as an integer constant.
  1281 
  1282 * Pure: ML function 'theory_of' renamed to 'theory';
  1283 
  1284 
  1285 *** Proof tools ***
  1286 
  1287 * Simplifier:
  1288   1. Asm_full_simp_tac is now more aggressive.
  1289      1. It will sometimes reorient premises if that increases their power to
  1290         simplify.
  1291      2. It does no longer proceed strictly from left to right but may also
  1292         rotate premises to achieve further simplification.
  1293      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1294      old Asm_full_simp_tac in that it does not rotate premises.
  1295   2. The simplifier now knows a little bit about nat-arithmetic.
  1296 
  1297 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1298 allows for selected deletion of wrappers, by introduction of names for
  1299 wrapper functionals.  This implies that addbefore, addSbefore,
  1300 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1301 and that adding two tactics with the same name overwrites the first
  1302 one (emitting a warning).
  1303   type wrapper = (int -> tactic) -> (int -> tactic)
  1304   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1305   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1306   delWrapper, delSWrapper: claset *  string            -> claset
  1307   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1308 
  1309 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1310 semantics; addbefore now affects only the unsafe part of step_tac
  1311 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1312 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1313 by Force_tac;
  1314 
  1315 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1316 compWrapper; added safe wrapper (and access functions for it);
  1317 
  1318 * HOL/split_all_tac is now much faster and fails if there is nothing
  1319 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1320 and the names of the automatically generated variables have changed.
  1321 split_all_tac has moved within claset() from unsafe wrappers to safe
  1322 wrappers, which means that !!-bound variables are split much more
  1323 aggressively, and safe_tac and clarify_tac now split such variables.
  1324 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1325 Note: the same holds for record_split_tac, which does the job of
  1326 split_all_tac for record fields.
  1327 
  1328 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1329 permanently to the default simpset using Addsplits just like
  1330 Addsimps. They can be removed via Delsplits just like
  1331 Delsimps. Lower-case versions are also available.
  1332 
  1333 * HOL/Simplifier: The rule split_if is now part of the default
  1334 simpset. This means that the simplifier will eliminate all occurrences
  1335 of if-then-else in the conclusion of a goal. To prevent this, you can
  1336 either remove split_if completely from the default simpset by
  1337 `Delsplits [split_if]' or remove it in a specific call of the
  1338 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1339 other case splitting rules to/from the default simpset: every datatype
  1340 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1341 t is the name of the datatype).
  1342 
  1343 * Classical reasoner / Simplifier combination: new force_tac (and
  1344 derivatives Force_tac, force) combines rewriting and classical
  1345 reasoning (and whatever other tools) similarly to auto_tac, but is
  1346 aimed to solve the given subgoal completely.
  1347 
  1348 
  1349 *** General ***
  1350 
  1351 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1352 and `goalw': the theory is no longer needed as an explicit argument -
  1353 the current theory context is used; assumptions are no longer returned
  1354 at the ML-level unless one of them starts with ==> or !!; it is
  1355 recommended to convert to these new commands using isatool fixgoal
  1356 (backup your sources first!);
  1357 
  1358 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1359 the current theory context, and 'theory' to lookup stored theories;
  1360 
  1361 * new theory section 'locale' for declaring constants, assumptions and
  1362 definitions that have local scope;
  1363 
  1364 * new theory section 'nonterminals' for purely syntactic types;
  1365 
  1366 * new theory section 'setup' for generic ML setup functions
  1367 (e.g. package initialization);
  1368 
  1369 * the distribution now includes Isabelle icons: see
  1370 lib/logo/isabelle-{small,tiny}.xpm;
  1371 
  1372 * isatool install - install binaries with absolute references to
  1373 ISABELLE_HOME/bin;
  1374 
  1375 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1376 
  1377 * print mode 'emacs' reserved for Isamode;
  1378 
  1379 * support multiple print (ast) translations per constant name;
  1380 
  1381 * theorems involving oracles are now printed with a suffixed [!];
  1382 
  1383 
  1384 *** HOL ***
  1385 
  1386 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1387 
  1388 * HOL/inductive package reorganized and improved: now supports mutual
  1389 definitions such as
  1390 
  1391   inductive EVEN ODD
  1392     intrs
  1393       null "0 : EVEN"
  1394       oddI "n : EVEN ==> Suc n : ODD"
  1395       evenI "n : ODD ==> Suc n : EVEN"
  1396 
  1397 new theorem list "elims" contains an elimination rule for each of the
  1398 recursive sets; inductive definitions now handle disjunctive premises
  1399 correctly (also ZF);
  1400 
  1401 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1402 "mutual_induct" no longer exists - the induction rule is always
  1403 contained in "induct";
  1404 
  1405 
  1406 * HOL/datatype package re-implemented and greatly improved: now
  1407 supports mutually recursive datatypes such as
  1408 
  1409   datatype
  1410     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1411             | SUM ('a aexp) ('a aexp)
  1412             | DIFF ('a aexp) ('a aexp)
  1413             | NUM 'a
  1414   and
  1415     'a bexp = LESS ('a aexp) ('a aexp)
  1416             | AND ('a bexp) ('a bexp)
  1417             | OR ('a bexp) ('a bexp)
  1418 
  1419 as well as indirectly recursive datatypes such as
  1420 
  1421   datatype
  1422     ('a, 'b) term = Var 'a
  1423                   | App 'b ((('a, 'b) term) list)
  1424 
  1425 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1426 induction on mutually / indirectly recursive datatypes.
  1427 
  1428 Primrec equations are now stored in theory and can be accessed via
  1429 <function_name>.simps.
  1430 
  1431 INCOMPATIBILITIES:
  1432 
  1433   - Theories using datatypes must now have theory Datatype as an
  1434     ancestor.
  1435   - The specific <typename>.induct_tac no longer exists - use the
  1436     generic induct_tac instead.
  1437   - natE has been renamed to nat.exhaust - use exhaust_tac
  1438     instead of res_inst_tac ... natE. Note that the variable
  1439     names in nat.exhaust differ from the names in natE, this
  1440     may cause some "fragile" proofs to fail.
  1441   - The theorems split_<typename>_case and split_<typename>_case_asm
  1442     have been renamed to <typename>.split and <typename>.split_asm.
  1443   - Since default sorts of type variables are now handled correctly,
  1444     some datatype definitions may have to be annotated with explicit
  1445     sort constraints.
  1446   - Primrec definitions no longer require function name and type
  1447     of recursive argument.
  1448 
  1449 Consider using isatool fixdatatype to adapt your theories and proof
  1450 scripts to the new package (backup your sources first!).
  1451 
  1452 
  1453 * HOL/record package: considerably improved implementation; now
  1454 includes concrete syntax for record types, terms, updates; theorems
  1455 for surjective pairing and splitting !!-bound record variables; proof
  1456 support is as follows:
  1457 
  1458   1) standard conversions (selectors or updates applied to record
  1459 constructor terms) are part of the standard simpset;
  1460 
  1461   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1462 made part of standard simpset and claset via addIffs;
  1463 
  1464   3) a tactic for record field splitting (record_split_tac) is part of
  1465 the standard claset (addSWrapper);
  1466 
  1467 To get a better idea about these rules you may retrieve them via
  1468 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1469 the name of your record type.
  1470 
  1471 The split tactic 3) conceptually simplifies by the following rule:
  1472 
  1473   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1474 
  1475 Thus any record variable that is bound by meta-all will automatically
  1476 blow up into some record constructor term, consequently the
  1477 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1478 solve record problems automatically.
  1479 
  1480 
  1481 * reorganized the main HOL image: HOL/Integ and String loaded by
  1482 default; theory Main includes everything;
  1483 
  1484 * automatic simplification of integer sums and comparisons, using cancellation;
  1485 
  1486 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1487 
  1488 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1489 
  1490 * many new identities for unions, intersections, set difference, etc.;
  1491 
  1492 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1493 called split_if, split_split, split_sum_case and split_nat_case (to go
  1494 with add/delsplits);
  1495 
  1496 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1497 (?x::unit) = (); this is made part of the default simpset, which COULD
  1498 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1499 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1500 unit_abs_eta_conv is added in order to counter the effect of
  1501 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1502 %u.f();
  1503 
  1504 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1505 makes more sense);
  1506 
  1507 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1508   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1509   disjointness reasoning but breaking a few old proofs.
  1510 
  1511 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1512 to 'converse' from 'inverse' (for compatibility with ZF and some
  1513 literature);
  1514 
  1515 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1516 the well-founded relation;
  1517 
  1518 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1519     Compl A.  The "Compl" syntax remains available as input syntax for this
  1520     release ONLY.
  1521 
  1522 * HOL/Update: new theory of function updates:
  1523     f(a:=b) == %x. if x=a then b else f x
  1524 may also be iterated as in f(a:=b,c:=d,...);
  1525 
  1526 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1527 
  1528 * HOL/List:
  1529   - new function list_update written xs[i:=v] that updates the i-th
  1530     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1531   - new function `upt' written [i..j(] which generates the list
  1532     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1533     bound write [i..j], which is a shorthand for [i..j+1(].
  1534   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1535 
  1536 * HOL/Arith:
  1537   - removed 'pred' (predecessor) function;
  1538   - generalized some theorems about n-1;
  1539   - many new laws about "div" and "mod";
  1540   - new laws about greatest common divisors (see theory ex/Primes);
  1541 
  1542 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1543 instead of "inverse";
  1544 
  1545 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1546   of the multiset ordering;
  1547 
  1548 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1549   (not included by default);
  1550 
  1551 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1552 
  1553 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1554   programs, i.e. different program variables may have different types.
  1555 
  1556 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1557   [previously, this check worked only if the rewrite rule was unconditional]
  1558   Now rew can involve either definitions or equalities (either == or =).
  1559 
  1560 
  1561 *** ZF ***
  1562 
  1563 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1564   only the theorems proved on ZF.ML;
  1565 
  1566 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1567   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1568   disjointness reasoning but breaking a few old proofs.
  1569 
  1570 * ZF/Update: new theory of function updates
  1571     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1572   may also be iterated as in f(a:=b,c:=d,...);
  1573 
  1574 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1575 
  1576 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1577   [previously, this check worked only if the rewrite rule was unconditional]
  1578   Now rew can involve either definitions or equalities (either == or =).
  1579 
  1580 * case_tac provided for compatibility with HOL
  1581     (like the old excluded_middle_tac, but with subgoals swapped)
  1582 
  1583 
  1584 *** Internal programming interfaces ***
  1585 
  1586 * Pure: several new basic modules made available for general use, see
  1587 also src/Pure/README;
  1588 
  1589 * improved the theory data mechanism to support encapsulation (data
  1590 kind name replaced by private Object.kind, acting as authorization
  1591 key); new type-safe user interface via functor TheoryDataFun; generic
  1592 print_data function becomes basically useless;
  1593 
  1594 * removed global_names compatibility flag -- all theory declarations
  1595 are qualified by default;
  1596 
  1597 * module Pure/Syntax now offers quote / antiquote translation
  1598 functions (useful for Hoare logic etc. with implicit dependencies);
  1599 see HOL/ex/Antiquote for an example use;
  1600 
  1601 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1602 cterm -> thm;
  1603 
  1604 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1605 subgoal;
  1606 
  1607 * Display.print_goals function moved to Locale.print_goals;
  1608 
  1609 * standard print function for goals supports current_goals_markers
  1610 variable for marking begin of proof, end of proof, start of goal; the
  1611 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1612 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1613 for example;
  1614 
  1615 
  1616 
  1617 New in Isabelle98 (January 1998)
  1618 --------------------------------
  1619 
  1620 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1621 
  1622 * changed lexical syntax of terms / types: dots made part of long
  1623 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1624 
  1625 * simpset (and claset) reference variable replaced by functions
  1626 simpset / simpset_ref;
  1627 
  1628 * no longer supports theory aliases (via merge) and non-trivial
  1629 implicit merge of thms' signatures;
  1630 
  1631 * most internal names of constants changed due to qualified names;
  1632 
  1633 * changed Pure/Sequence interface (see Pure/seq.ML);
  1634 
  1635 
  1636 *** General Changes ***
  1637 
  1638 * hierachically structured name spaces (for consts, types, axms, thms
  1639 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1640 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1641 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1642 long_names for fully qualified output names; NOTE: ML programs
  1643 (special tactics, packages etc.) referring to internal names may have
  1644 to be adapted to cope with fully qualified names; in case of severe
  1645 backward campatibility problems try setting 'global_names' at compile
  1646 time to have enrything declared within a flat name space; one may also
  1647 fine tune name declarations in theories via the 'global' and 'local'
  1648 section;
  1649 
  1650 * reimplemented the implicit simpset and claset using the new anytype
  1651 data filed in signatures; references simpset:simpset ref etc. are
  1652 replaced by functions simpset:unit->simpset and
  1653 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1654 to patch your ML files accordingly;
  1655 
  1656 * HTML output now includes theory graph data for display with Java
  1657 applet or isatool browser; data generated automatically via isatool
  1658 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1659 
  1660 * defs may now be conditional; improved rewrite_goals_tac to handle
  1661 conditional equations;
  1662 
  1663 * defs now admits additional type arguments, using TYPE('a) syntax;
  1664 
  1665 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1666 creates a new theory node; implicit merge of thms' signatures is
  1667 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1668 transfer:theory->thm->thm in (rare) cases;
  1669 
  1670 * improved handling of draft signatures / theories; draft thms (and
  1671 ctyps, cterms) are automatically promoted to real ones;
  1672 
  1673 * slightly changed interfaces for oracles: admit many per theory, named
  1674 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1675 
  1676 * print_goals: optional output of const types (set show_consts and
  1677 show_types);
  1678 
  1679 * improved output of warnings (###) and errors (***);
  1680 
  1681 * subgoal_tac displays a warning if the new subgoal has type variables;
  1682 
  1683 * removed old README and Makefiles;
  1684 
  1685 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1686 
  1687 * removed obsolete init_pps and init_database;
  1688 
  1689 * deleted the obsolete tactical STATE, which was declared by
  1690     fun STATE tacfun st = tacfun st st;
  1691 
  1692 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1693 (which abbreviates $HOME);
  1694 
  1695 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1696 use isatool fixseq to adapt your ML programs (this works for fully
  1697 qualified references to the Sequence structure only!);
  1698 
  1699 * use_thy no longer requires writable current directory; it always
  1700 reloads .ML *and* .thy file, if either one is out of date;
  1701 
  1702 
  1703 *** Classical Reasoner ***
  1704 
  1705 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1706 tactics that use classical reasoning to simplify a subgoal without
  1707 splitting it into several subgoals;
  1708 
  1709 * Safe_tac: like safe_tac but uses the default claset;
  1710 
  1711 
  1712 *** Simplifier ***
  1713 
  1714 * added simplification meta rules:
  1715     (asm_)(full_)simplify: simpset -> thm -> thm;
  1716 
  1717 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1718 logics (again);
  1719 
  1720 * added prems argument to simplification procedures;
  1721 
  1722 * HOL, FOL, ZF: added infix function `addsplits':
  1723   instead of `<simpset> setloop (split_tac <thms>)'
  1724   you can simply write `<simpset> addsplits <thms>'
  1725 
  1726 
  1727 *** Syntax ***
  1728 
  1729 * TYPE('a) syntax for type reflection terms;
  1730 
  1731 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1732 
  1733 * pretty printer: changed order of mixfix annotation preference (again!);
  1734 
  1735 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1736 
  1737 
  1738 *** HOL ***
  1739 
  1740 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1741   with `addloop' of the simplifier to faciliate case splitting in premises.
  1742 
  1743 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1744 
  1745 * HOL/Auth: new protocol proofs including some for the Internet
  1746   protocol TLS;
  1747 
  1748 * HOL/Map: new theory of `maps' a la VDM;
  1749 
  1750 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1751 cancelling out common nat summands from =, <, <= (in)equalities, or
  1752 differences; simplification procedures nat_cancel_factor for
  1753 cancelling common factor from =, <, <= (in)equalities over natural
  1754 sums; nat_cancel contains both kinds of procedures, it is installed by
  1755 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1756 
  1757 * HOL/simplifier: terms of the form
  1758   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1759   are rewritten to
  1760   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1761   and those of the form
  1762   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1763   are rewritten to
  1764   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1765 
  1766 * HOL/datatype
  1767   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1768 
  1769   P(t_case f1 ... fn x) =
  1770      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1771         ...
  1772        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1773      )
  1774 
  1775   and a theorem `split_t_case_asm' of the form
  1776 
  1777   P(t_case f1 ... fn x) =
  1778     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1779         ...
  1780        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1781      )
  1782   which can be added to a simpset via `addsplits'. The existing theorems
  1783   expand_list_case and expand_option_case have been renamed to
  1784   split_list_case and split_option_case.
  1785 
  1786 * HOL/Arithmetic:
  1787   - `pred n' is automatically converted to `n-1'.
  1788     Users are strongly encouraged not to use `pred' any longer,
  1789     because it will disappear altogether at some point.
  1790   - Users are strongly encouraged to write "0 < n" rather than
  1791     "n ~= 0". Theorems and proof tools have been modified towards this
  1792     `standard'.
  1793 
  1794 * HOL/Lists:
  1795   the function "set_of_list" has been renamed "set" (and its theorems too);
  1796   the function "nth" now takes its arguments in the reverse order and
  1797   has acquired the infix notation "!" as in "xs!n".
  1798 
  1799 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1800 
  1801 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1802   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1803 
  1804 * HOL/record: extensible records with schematic structural subtyping
  1805 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1806 still lacks various theorems and concrete record syntax;
  1807 
  1808 
  1809 *** HOLCF ***
  1810 
  1811 * removed "axioms" and "generated by" sections;
  1812 
  1813 * replaced "ops" section by extended "consts" section, which is capable of
  1814   handling the continuous function space "->" directly;
  1815 
  1816 * domain package:
  1817   . proves theorems immediately and stores them in the theory,
  1818   . creates hierachical name space,
  1819   . now uses normal mixfix annotations (instead of cinfix...),
  1820   . minor changes to some names and values (for consistency),
  1821   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1822   . separator between mutual domain defs: changed "," to "and",
  1823   . improved handling of sort constraints;  now they have to
  1824     appear on the left-hand side of the equations only;
  1825 
  1826 * fixed LAM <x,y,zs>.b syntax;
  1827 
  1828 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1829 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1830 
  1831 
  1832 *** FOL and ZF ***
  1833 
  1834 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1835   with `addloop' of the simplifier to faciliate case splitting in premises.
  1836 
  1837 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1838 in HOL, they strip ALL and --> from proved theorems;
  1839 
  1840 
  1841 
  1842 New in Isabelle94-8 (May 1997)
  1843 ------------------------------
  1844 
  1845 *** General Changes ***
  1846 
  1847 * new utilities to build / run / maintain Isabelle etc. (in parts
  1848 still somewhat experimental); old Makefiles etc. still functional;
  1849 
  1850 * new 'Isabelle System Manual';
  1851 
  1852 * INSTALL text, together with ./configure and ./build scripts;
  1853 
  1854 * reimplemented type inference for greater efficiency, better error
  1855 messages and clean internal interface;
  1856 
  1857 * prlim command for dealing with lots of subgoals (an easier way of
  1858 setting goals_limit);
  1859 
  1860 
  1861 *** Syntax ***
  1862 
  1863 * supports alternative (named) syntax tables (parser and pretty
  1864 printer); internal interface is provided by add_modesyntax(_i);
  1865 
  1866 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1867 be used in conjunction with the Isabelle symbol font; uses the
  1868 "symbols" syntax table;
  1869 
  1870 * added token_translation interface (may translate name tokens in
  1871 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1872 the current print_mode); IMPORTANT: user print translation functions
  1873 are responsible for marking newly introduced bounds
  1874 (Syntax.mark_boundT);
  1875 
  1876 * token translations for modes "xterm" and "xterm_color" that display
  1877 names in bold, underline etc. or colors (which requires a color
  1878 version of xterm);
  1879 
  1880 * infixes may now be declared with names independent of their syntax;
  1881 
  1882 * added typed_print_translation (like print_translation, but may
  1883 access type of constant);
  1884 
  1885 
  1886 *** Classical Reasoner ***
  1887 
  1888 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1889 some limitations.  Blast_tac...
  1890   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1891   + ignores elimination rules that don't have the correct format
  1892         (the conclusion MUST be a formula variable)
  1893   + ignores types, which can make HOL proofs fail
  1894   + rules must not require higher-order unification, e.g. apply_type in ZF
  1895     [message "Function Var's argument not a bound variable" relates to this]
  1896   + its proof strategy is more general but can actually be slower
  1897 
  1898 * substitution with equality assumptions no longer permutes other
  1899 assumptions;
  1900 
  1901 * minor changes in semantics of addafter (now called addaltern); renamed
  1902 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1903 (and access functions for it);
  1904 
  1905 * improved combination of classical reasoner and simplifier:
  1906   + functions for handling clasimpsets
  1907   + improvement of addss: now the simplifier is called _after_ the
  1908     safe steps.
  1909   + safe variant of addss called addSss: uses safe simplifications
  1910     _during_ the safe steps. It is more complete as it allows multiple
  1911     instantiations of unknowns (e.g. with slow_tac).
  1912 
  1913 *** Simplifier ***
  1914 
  1915 * added interface for simplification procedures (functions that
  1916 produce *proven* rewrite rules on the fly, depending on current
  1917 redex);
  1918 
  1919 * ordering on terms as parameter (used for ordered rewriting);
  1920 
  1921 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1922 
  1923 * the solver is now split into a safe and an unsafe part.
  1924 This should be invisible for the normal user, except that the
  1925 functions setsolver and addsolver have been renamed to setSolver and
  1926 addSolver; added safe_asm_full_simp_tac;
  1927 
  1928 
  1929 *** HOL ***
  1930 
  1931 * a generic induction tactic `induct_tac' which works for all datatypes and
  1932 also for type `nat';
  1933 
  1934 * a generic case distinction tactic `exhaust_tac' which works for all
  1935 datatypes and also for type `nat';
  1936 
  1937 * each datatype comes with a function `size';
  1938 
  1939 * patterns in case expressions allow tuple patterns as arguments to
  1940 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1941 
  1942 * primrec now also works with type nat;
  1943 
  1944 * recdef: a new declaration form, allows general recursive functions to be
  1945 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1946 
  1947 * the constant for negation has been renamed from "not" to "Not" to
  1948 harmonize with FOL, ZF, LK, etc.;
  1949 
  1950 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1951 infinite lists;
  1952 
  1953 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1954 
  1955 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1956 problems in commutative rings, using axiomatic type classes for + and *;
  1957 
  1958 * more examples in HOL/MiniML and HOL/Auth;
  1959 
  1960 * more default rewrite rules for quantifiers, union/intersection;
  1961 
  1962 * a new constant `arbitrary == @x.False';
  1963 
  1964 * HOLCF/IOA replaces old HOL/IOA;
  1965 
  1966 * HOLCF changes: derived all rules and arities
  1967   + axiomatic type classes instead of classes
  1968   + typedef instead of faking type definitions
  1969   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1970   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1971   + eliminated the types void, one, tr
  1972   + use unit lift and bool lift (with translations) instead of one and tr
  1973   + eliminated blift from Lift3.thy (use Def instead of blift)
  1974   all eliminated rules are derived as theorems --> no visible changes ;
  1975 
  1976 
  1977 *** ZF ***
  1978 
  1979 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1980 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1981 as ZF_cs addSIs [equalityI];
  1982 
  1983 
  1984 
  1985 New in Isabelle94-7 (November 96)
  1986 ---------------------------------
  1987 
  1988 * allowing negative levels (as offsets) in prlev and choplev;
  1989 
  1990 * super-linear speedup for large simplifications;
  1991 
  1992 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1993 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1994 FAIL); can suppress it using the command Delsimps (ex_simps @
  1995 all_simps); De Morgan laws are also now included, by default;
  1996 
  1997 * improved printing of ==>  :  ~:
  1998 
  1999 * new object-logic "Sequents" adds linear logic, while replacing LK
  2000 and Modal (thanks to Sara Kalvala);
  2001 
  2002 * HOL/Auth: correctness proofs for authentication protocols;
  2003 
  2004 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2005 examples on HOL/Auth);
  2006 
  2007 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2008 the rewriter and classical reasoner simultaneously;
  2009 
  2010 * function uresult no longer returns theorems in "standard" format;
  2011 regain previous version by: val uresult = standard o uresult;
  2012 
  2013 
  2014 
  2015 New in Isabelle94-6
  2016 -------------------
  2017 
  2018 * oracles -- these establish an interface between Isabelle and trusted
  2019 external reasoners, which may deliver results as theorems;
  2020 
  2021 * proof objects (in particular record all uses of oracles);
  2022 
  2023 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2024 
  2025 * "constdefs" section in theory files;
  2026 
  2027 * "primrec" section (HOL) no longer requires names;
  2028 
  2029 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2030 
  2031 
  2032 
  2033 New in Isabelle94-5
  2034 -------------------
  2035 
  2036 * reduced space requirements;
  2037 
  2038 * automatic HTML generation from theories;
  2039 
  2040 * theory files no longer require "..." (quotes) around most types;
  2041 
  2042 * new examples, including two proofs of the Church-Rosser theorem;
  2043 
  2044 * non-curried (1994) version of HOL is no longer distributed;
  2045 
  2046 
  2047 
  2048 New in Isabelle94-4
  2049 -------------------
  2050 
  2051 * greatly reduced space requirements;
  2052 
  2053 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2054 
  2055 * searchable theorem database (see the section "Retrieving theorems" on
  2056 page 8 of the Reference Manual);
  2057 
  2058 * new examples, including Grabczewski's monumental case study of the
  2059 Axiom of Choice;
  2060 
  2061 * The previous version of HOL renamed to Old_HOL;
  2062 
  2063 * The new version of HOL (previously called CHOL) uses a curried syntax
  2064 for functions.  Application looks like f a b instead of f(a,b);
  2065 
  2066 * Mutually recursive inductive definitions finally work in HOL;
  2067 
  2068 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2069 translates to the operator "split";
  2070 
  2071 
  2072 
  2073 New in Isabelle94-3
  2074 -------------------
  2075 
  2076 * new infix operator, addss, allowing the classical reasoner to
  2077 perform simplification at each step of its search.  Example:
  2078         fast_tac (cs addss ss)
  2079 
  2080 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2081 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2082 look like (a,b) instead of <a,b>;
  2083 
  2084 * PLEASE NOTE: CHOL will eventually replace HOL!
  2085 
  2086 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2087 It translates to the operator "split".  A new theory of integers is available;
  2088 
  2089 * In ZF, integer numerals now denote two's-complement binary integers.
  2090 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2091 
  2092 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2093 of the Axiom of Choice;
  2094 
  2095 
  2096 
  2097 New in Isabelle94-2
  2098 -------------------
  2099 
  2100 * Significantly faster resolution;
  2101 
  2102 * the different sections in a .thy file can now be mixed and repeated
  2103 freely;
  2104 
  2105 * Database of theorems for FOL, HOL and ZF.  New
  2106 commands including qed, qed_goal and bind_thm store theorems in the database.
  2107 
  2108 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2109 a given theory (thms_of), or find out what theory a theorem was proved in
  2110 (theory_of_thm);
  2111 
  2112 * Bugs fixed in the inductive definition and datatype packages;
  2113 
  2114 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2115 and HOL_dup_cs obsolete;
  2116 
  2117 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2118 have been removed;
  2119 
  2120 * Simpler definition of function space in ZF;
  2121 
  2122 * new results about cardinal and ordinal arithmetic in ZF;
  2123 
  2124 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2125 types;
  2126 
  2127 
  2128 $Id$