NEWS
author wenzelm
Fri Jan 11 18:49:25 2002 +0100 (2002-01-11)
changeset 12724 beedc794bd67
parent 12707 4013be8572c5
child 12728 4ed8ab7d677d
permissions -rw-r--r--
Isabelle2002 (January 2002);
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2002 (January 2002)
     6 ----------------------------------
     7 
     8 *** Document preparation ***
     9 
    10 * greatly simplified document preparation setup, including more
    11 graceful interpretation of isatool usedir -i/-d/-D options, and more
    12 instructive isatool mkdir; users should basically be able to get
    13 started with "isatool mkdir Test && isatool make";
    14 
    15 * theory dependency graph may now be incorporated into documents;
    16 isatool usedir -g true will produce session_graph.eps/.pdf for use
    17 with \includegraphics of LaTeX;
    18 
    19 * proper spacing of consecutive markup elements, especially text
    20 blocks after section headings;
    21 
    22 * support bold style (for single symbols only), input syntax is like
    23 this: "\<^bold>\<alpha>" or "\<^bold>A";
    24 
    25 * \<bullet> is now output as bold \cdot by default, which looks much
    26 better in printed text;
    27 
    28 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
    29 note that these symbols are currently unavailable in Proof General /
    30 X-Symbol; added \<euro> symbol;
    31 
    32 * isatool latex no longer depends on changed TEXINPUTS, instead
    33 isatool document copies the Isabelle style files to the target
    34 location;
    35 
    36 
    37 *** Isar ***
    38 
    39 * Pure/Provers: improved proof by cases and induction;
    40   - 'case' command admits impromptu naming of parameters (such as
    41     "case (Suc n)");
    42   - 'induct' method divinates rule instantiation from the inductive
    43     claim; no longer requires excessive ?P bindings for proper
    44     instantiation of cases;
    45   - 'induct' method properly enumerates all possibilities of set/type
    46     rules; as a consequence facts may be also passed through *type*
    47     rules without further ado;
    48   - 'induct' method now derives symbolic cases from the *rulified*
    49     rule (before it used to rulify cases stemming from the internal
    50     atomized version); this means that the context of a non-atomic
    51     statement becomes is included in the hypothesis, avoiding the
    52     slightly cumbersome show "PROP ?case" form;
    53   - 'induct' may now use elim-style induction rules without chaining
    54     facts, using ``missing'' premises from the goal state; this allows
    55     rules stemming from inductive sets to be applied in unstructured
    56     scripts, while still benefitting from proper handling of non-atomic
    57     statements; NB: major inductive premises need to be put first, all
    58     the rest of the goal is passed through the induction;
    59   - 'induct' proper support for mutual induction involving non-atomic
    60     rule statements (uses the new concept of simultaneous goals, see
    61     below);
    62   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    63   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    64   - moved induct/cases attributes to Pure, methods to Provers;
    65   - generic method setup instantiated for FOL and HOL;
    66 
    67 * Pure: support multiple simultaneous goal statements, for example
    68 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    69 meta-level mechanism, this acts as if several individual goals had
    70 been stated separately; in particular common proof methods need to be
    71 repeated in order to cover all claims; note that a single elimination
    72 step is *not* sufficient to establish the two conjunctions, so this
    73 fails:
    74 
    75   assume "A & B" then have A and B ..   (*".." fails*)
    76 
    77 better use "obtain" in situations as above; alternative refer to
    78 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    79 
    80 * Pure: proper integration with ``locales''; unlike the original
    81 version by Florian Kammüller, Isar locales package high-level proof
    82 contexts rather than raw logical ones (e.g. we admit to include
    83 attributes everywhere); operations on locales include merge and
    84 rename; e.g. see HOL/ex/Locales.thy;
    85 
    86 * Pure: the following commands have been ``localized'', supporting a
    87 target locale specification "(in name)": 'lemma', 'theorem',
    88 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
    89 stored both within the locale and at the theory level (exported and
    90 qualified by the locale name);
    91 
    92 * Pure: theory goals now support ad-hoc contexts, which are discharged
    93 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    94 coincides with that of a locale body;
    95 
    96 * Pure: renamed "antecedent" case to "rule_context";
    97 
    98 * Pure: added 'corollary' command;
    99 
   100 * Pure: fixed 'token_translation' command;
   101 
   102 * Pure: removed obsolete 'exported' attribute;
   103 
   104 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   105 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   106 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   107 
   108 * Pure: method 'atomize' presents local goal premises as object-level
   109 statements (atomic meta-level propositions); setup controlled via
   110 rewrite rules declarations of 'atomize' attribute; example
   111 application: 'induct' method with proper rule statements in improper
   112 proof *scripts*;
   113 
   114 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   115 now consider the syntactic context of assumptions, giving a better
   116 chance to get type-inference of the arguments right (this is
   117 especially important for locales);
   118 
   119 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   120 mode;
   121 
   122 * Pure/obtain: the formal conclusion "thesis", being marked as
   123 ``internal'', may no longer be reference directly in the text;
   124 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   125 situations;
   126 
   127 * Pure: generic 'sym' attribute which declares a rule both as pure
   128 'elim?' and for the 'symmetric' operation;
   129 
   130 * Pure/Provers/classical: simplified integration with pure rule
   131 attributes and methods; the classical "intro?/elim?/dest?"
   132 declarations coincide with the pure ones; the "rule" method no longer
   133 includes classically swapped intros; "intro" and "elim" methods no
   134 longer pick rules from the context; also got rid of ML declarations
   135 AddXIs/AddXEs/AddXDs; all of this has some potential for
   136 INCOMPATIBILITY;
   137 
   138 * Provers/classical: attribute 'swapped' produces classical inversions
   139 of introduction rules;
   140 
   141 * Provers/simplifier: 'simplified' attribute may refer to explicit
   142 rules instead of full simplifier context; 'iff' attribute handles
   143 conditional rules;
   144 
   145 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   146 
   147 * HOL: 'recdef' now fails on unfinished automated proofs, use
   148 "(permissive)" option to recover old behavior;
   149 
   150 * HOL: 'inductive' no longer features separate (collective) attributes
   151 for 'intros' (was found too confusing);
   152 
   153 * HOL: properly declared induction rules less_induct and
   154 wf_induct_rule;
   155 
   156 
   157 *** HOL ***
   158 
   159 * HOL: moved over to sane numeral syntax; the new policy is as
   160 follows:
   161 
   162   - 0 and 1 are polymorphic constants, which are defined on any
   163   numeric type (nat, int, real etc.);
   164 
   165   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   166   binary representation internally;
   167 
   168   - type nat has special constructor Suc, and generally prefers Suc 0
   169   over 1::nat and Suc (Suc 0) over 2::nat;
   170 
   171 This change may cause significant problems of INCOMPATIBILITY; here
   172 are some hints on converting existing sources:
   173 
   174   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   175   entities, so expressions involving "-" (unary or binary minus) need
   176   to be spaced properly;
   177 
   178   - existing occurrences of "1" may need to be constraint "1::nat" or
   179   even replaced by Suc 0; similar for old "2";
   180 
   181   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   182 
   183   - remove all special provisions on numerals in proofs;
   184 
   185 * HOL: the class of all HOL types is now called "type" rather than
   186 "term"; INCOMPATIBILITY, need to adapt references to this type class
   187 in axclass/classes, instance/arities, and (usually rare) occurrences
   188 in typings (of consts etc.); internally the class is called
   189 "HOL.type", ML programs should refer to HOLogic.typeS;
   190 
   191 * HOL/record package improvements:
   192   - new derived operations "fields" to build a partial record section,
   193     "extend" to promote a fixed record to a record scheme, and
   194     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   195     declared as simp by default;
   196   - shared operations ("more", "fields", etc.) now need to be always
   197     qualified) --- potential INCOMPATIBILITY;
   198   - removed "make_scheme" operations (use "make" with "extend") --
   199     INCOMPATIBILITY;
   200   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   201   - provides cases/induct rules for use with corresponding Isar
   202     methods (for concrete records, record schemes, concrete more
   203     parts, and schematic more parts -- in that order);
   204   - internal definitions directly based on a light-weight abstract
   205     theory of product types over typedef rather than datatype;
   206 
   207 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   208 
   209 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   210 (beware of argument permutation!);
   211 
   212 * HOL: linorder_less_split superseded by linorder_cases;
   213 
   214 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   215 to peripheral theory "Hilbert_Choice";
   216 
   217 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   218 in this (rare) case use:
   219 
   220   delSWrapper "split_all_tac"
   221   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   222 
   223 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   224 MAY FAIL;
   225 
   226 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   227 Isabelle's type classes, ^ on functions and relations has too general
   228 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   229 necessary to attach explicit type constraints;
   230 
   231 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   232 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   233 (eg "compI" -> "rel_compI").
   234 
   235 * HOL: syntax translations now work properly with numerals and records
   236 expressions;
   237 
   238 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   239 of "lam" -- INCOMPATIBILITY;
   240 
   241 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   242 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   243 renamed "Product_Type.unit";
   244 
   245 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   246 
   247 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   248 Florian Kammüller);
   249 
   250 * HOL/IMP: updated and converted to new-style theory format; several
   251 parts turned into readable document, with proper Isar proof texts and
   252 some explanations (by Gerwin Klein);
   253 
   254 * HOL-Hyperreal is now a logic image;
   255 
   256 
   257 *** HOLCF ***
   258 
   259 * Isar: consts/constdefs supports mixfix syntax for continuous
   260 operations;
   261 
   262 * Isar: domain package adapted to new-style theory format, e.g. see
   263 HOLCF/ex/Dnat.thy;
   264 
   265 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   266 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   267 lift.induct_tac, always use UU instead of Undef;
   268 
   269 * HOLCF/IMP: updated and converted to new-style theory;
   270 
   271 
   272 *** ZF ***
   273 
   274 * Isar: proper integration of logic-specific tools and packages,
   275 including theory commands '(co)inductive', '(co)datatype',
   276 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   277 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   278 
   279 * theory Main no longer includes AC; for the Axiom of Choice, base
   280 your theory on Main_ZFC;
   281 
   282 * the integer library now covers quotients and remainders, with many
   283 laws relating division to addition, multiplication, etc.;
   284 
   285 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   286 typeless version of the formalism;
   287 
   288 * ZF/IMP: updated and converted to new-style theory format;
   289 
   290 * ZF/Induct: new directory for examples of inductive definitions,
   291 including theory Multiset for multiset orderings; converted to
   292 new-style theory format;
   293 
   294 
   295 *** General ***
   296 
   297 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   298 variable proof controls level of detail: 0 = no proofs (only oracle
   299 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   300 also ref manual for further ML interfaces;
   301 
   302 * Pure/axclass: removed obsolete ML interface
   303 goal_subclass/goal_arity;
   304 
   305 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   306 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   307 separate tokens, so expressions involving minus need to be spaced
   308 properly;
   309 
   310 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   311 rather than "infixl" or "infixr";
   312 
   313 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   314 sort constraint specifications in type inference; e.g. "x::_::foo"
   315 ensures that the type of "x" is of sort "foo" (but not necessarily a
   316 type variable);
   317 
   318 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   319 control output of nested => (types); the default behavior is
   320 "type_brackets";
   321 
   322 * Pure/syntax: builtin parse translation for "_constify" turns valued
   323 tokens into AST constants;
   324 
   325 * Pure/syntax: prefer later declarations of translations and print
   326 translation functions; potential INCOMPATIBILITY: need to reverse
   327 multiple declarations for same syntax element constant;
   328 
   329 * Provers/classical: renamed addaltern to addafter, addSaltern to
   330 addSafter;
   331 
   332 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   333 as well;
   334 
   335 * system: tested support for MacOS X; should be able to get Isabelle +
   336 Proof General to work in a plain Terminal after installing Poly/ML
   337 (e.g. from the Isabelle distribution area) and GNU bash alone
   338 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   339 support requires further installations, e.g. from
   340 http://fink.sourceforge.net/);
   341 
   342 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   343 
   344 * system: Proof General keywords specification is now part of the
   345 Isabelle distribution (see etc/isar-keywords.el);
   346 
   347 * system: some support for persistent Proof General sessions (refrain
   348 from outdating all loaded theories on startup);
   349 
   350 * system: smart selection of Isabelle process versus Isabelle
   351 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   352 run both "isabelle" and "Isabelle" even if file names are badly
   353 damaged (executable inspects the case of the first letter of its own
   354 name); added separate "isabelle-process" and "isabelle-interface";
   355 
   356 * system: refrain from any attempt at filtering input streams; no
   357 longer support ``8bit'' encoding of old isabelle font, instead proper
   358 iso-latin characters may now be used; the related isatools
   359 "symbolinput" and "nonascii" have disappeared as well;
   360 
   361 * system: removed old "xterm" interface (the print modes "xterm" and
   362 "xterm_color" are still available for direct use in a suitable
   363 terminal);
   364 
   365 
   366 
   367 New in Isabelle99-2 (February 2001)
   368 -----------------------------------
   369 
   370 *** Overview of INCOMPATIBILITIES ***
   371 
   372 * HOL: please note that theories in the Library and elsewhere often use the
   373 new-style (Isar) format; to refer to their theorems in an ML script you must
   374 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   375 
   376 * HOL: inductive package no longer splits induction rule aggressively,
   377 but only as far as specified by the introductions given; the old
   378 format may be recovered via ML function complete_split_rule or attribute
   379 'split_rule (complete)';
   380 
   381 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   382 gfp_Tarski to gfp_unfold;
   383 
   384 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   385 
   386 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   387 relation); infix "^^" has been renamed "``"; infix "``" has been
   388 renamed "`"; "univalent" has been renamed "single_valued";
   389 
   390 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   391 operation;
   392 
   393 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   394 
   395 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   396 
   397 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   398 consequence, it is no longer monotonic wrt. the local goal context
   399 (which is now passed through the inductive cases);
   400 
   401 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   402 \<gg> to \<ggreater>;
   403 
   404 
   405 *** Document preparation ***
   406 
   407 * \isabellestyle{NAME} selects version of Isabelle output (currently
   408 available: are "it" for near math-mode best-style output, "sl" for
   409 slanted text style, and "tt" for plain type-writer; if no
   410 \isabellestyle command is given, output is according to slanted
   411 type-writer);
   412 
   413 * support sub/super scripts (for single symbols only), input syntax is
   414 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   415 
   416 * some more standard symbols; see Appendix A of the system manual for
   417 the complete list of symbols defined in isabellesym.sty;
   418 
   419 * improved isabelle style files; more abstract symbol implementation
   420 (should now use \isamath{...} and \isatext{...} in custom symbol
   421 definitions);
   422 
   423 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   424 state; Note that presentation of goal states does not conform to
   425 actual human-readable proof documents.  Please do not include goal
   426 states into document output unless you really know what you are doing!
   427 
   428 * proper indentation of antiquoted output with proportional LaTeX
   429 fonts;
   430 
   431 * no_document ML operator temporarily disables LaTeX document
   432 generation;
   433 
   434 * isatool unsymbolize tunes sources for plain ASCII communication;
   435 
   436 
   437 *** Isar ***
   438 
   439 * Pure: Isar now suffers initial goal statements to contain unbound
   440 schematic variables (this does not conform to actual readable proof
   441 documents, due to unpredictable outcome and non-compositional proof
   442 checking); users who know what they are doing may use schematic goals
   443 for Prolog-style synthesis of proven results;
   444 
   445 * Pure: assumption method (an implicit finishing) now handles actual
   446 rules as well;
   447 
   448 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   449 initial goal, declare "that" only as Pure intro (only for single
   450 steps); the "that" rule assumption may now be involved in implicit
   451 finishing, thus ".." becomes a feasible for trivial obtains;
   452 
   453 * Pure: default proof step now includes 'intro_classes'; thus trivial
   454 instance proofs may be performed by "..";
   455 
   456 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   457 statements as well;
   458 
   459 * Pure: more robust selection of calculational rules;
   460 
   461 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   462 rule (as well as the assumption rule);
   463 
   464 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   465 lemmas, using the graph browser tool;
   466 
   467 * Pure: predict failure of "show" in interactive mode;
   468 
   469 * Pure: 'thms_containing' now takes actual terms as arguments;
   470 
   471 * HOL: improved method 'induct' --- now handles non-atomic goals
   472 (potential INCOMPATIBILITY); tuned error handling;
   473 
   474 * HOL: cases and induct rules now provide explicit hints about the
   475 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   476 any remaining facts are inserted into the goal verbatim;
   477 
   478 * HOL: local contexts (aka cases) may now contain term bindings as
   479 well; the 'cases' and 'induct' methods new provide a ?case binding for
   480 the result to be shown in each case;
   481 
   482 * HOL: added 'recdef_tc' command;
   483 
   484 * isatool convert assists in eliminating legacy ML scripts;
   485 
   486 
   487 *** HOL ***
   488 
   489 * HOL/Library: a collection of generic theories to be used together
   490 with main HOL; the theory loader path already includes this directory
   491 by default; the following existing theories have been moved here:
   492 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   493 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   494 
   495 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   496 modelling and verification task performed in Isabelle/HOL +
   497 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   498 
   499 * HOL/Algebra: special summation operator SUM no longer exists, it has
   500 been replaced by setsum; infix 'assoc' now has priority 50 (like
   501 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   502 'domain', this makes the theory consistent with mathematical
   503 literature;
   504 
   505 * HOL basics: added overloaded operations "inverse" and "divide"
   506 (infix "/"), syntax for generic "abs" operation, generic summation
   507 operator \<Sum>;
   508 
   509 * HOL/typedef: simplified package, provide more useful rules (see also
   510 HOL/subset.thy);
   511 
   512 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   513 now expressed as a proper nested rule (old-style tactic scripts may
   514 require atomize_strip_tac to cope with non-atomic premises);
   515 
   516 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   517 to "split_conv" (old name still available for compatibility);
   518 
   519 * HOL: improved concrete syntax for strings (e.g. allows translation
   520 rules with string literals);
   521 
   522 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   523  and Fleuriot's mechanization of analysis, including the transcendental
   524  functions for the reals;
   525 
   526 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   527 
   528 
   529 *** CTT ***
   530 
   531 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   532 "lam" is displayed as TWO lambda-symbols
   533 
   534 * CTT: theory Main now available, containing everything (that is, Bool
   535 and Arith);
   536 
   537 
   538 *** General ***
   539 
   540 * Pure: the Simplifier has been implemented properly as a derived rule
   541 outside of the actual kernel (at last!); the overall performance
   542 penalty in practical applications is about 50%, while reliability of
   543 the Isabelle inference kernel has been greatly improved;
   544 
   545 * print modes "brackets" and "no_brackets" control output of nested =>
   546 (types) and ==> (props); the default behaviour is "brackets";
   547 
   548 * Provers: fast_tac (and friends) now handle actual object-logic rules
   549 as assumptions as well;
   550 
   551 * system: support Poly/ML 4.0;
   552 
   553 * system: isatool install handles KDE version 1 or 2;
   554 
   555 
   556 
   557 New in Isabelle99-1 (October 2000)
   558 ----------------------------------
   559 
   560 *** Overview of INCOMPATIBILITIES ***
   561 
   562 * HOL: simplification of natural numbers is much changed; to partly
   563 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   564 issue the following ML commands:
   565 
   566   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   567   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   568 
   569 * HOL: simplification no longer dives into case-expressions; this is
   570 controlled by "t.weak_case_cong" for each datatype t;
   571 
   572 * HOL: nat_less_induct renamed to less_induct;
   573 
   574 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   575 fixsome to patch .thy and .ML sources automatically;
   576 
   577   select_equality  -> some_equality
   578   select_eq_Ex     -> some_eq_ex
   579   selectI2EX       -> someI2_ex
   580   selectI2         -> someI2
   581   selectI          -> someI
   582   select1_equality -> some1_equality
   583   Eps_sym_eq       -> some_sym_eq_trivial
   584   Eps_eq           -> some_eq_trivial
   585 
   586 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   587 
   588 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   589 instead);
   590 
   591 * HOL: the recursion equations generated by 'recdef' are now called
   592 f.simps instead of f.rules;
   593 
   594 * HOL: qed_spec_mp now also handles bounded ALL as well;
   595 
   596 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   597 sometimes be needed;
   598 
   599 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   600 
   601 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   602 
   603 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   604 product is now "<*>" instead of "Times"; the lexicographic product is
   605 now "<*lex*>" instead of "**";
   606 
   607 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   608 of main HOL, but was unused); better use HOL's datatype package;
   609 
   610 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   611 the old syntax may be recovered as follows:
   612 
   613   syntax (symbols)
   614     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   615       (infixl "\\<oplus>" 100)
   616 
   617 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   618 
   619 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   620 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   621 internally;
   622 
   623 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   624 changed from A/r to A//r;
   625 
   626 * ZF: new treatment of arithmetic (nat & int) may break some old
   627 proofs;
   628 
   629 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   630 rulify -> rule_format, elimify -> elim_format, ...);
   631 
   632 * Isar/Provers: intro/elim/dest attributes changed; renamed
   633 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   634 should have to change intro!! to intro? only); replaced "delrule" by
   635 "rule del";
   636 
   637 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   638 
   639 * Provers: strengthened force_tac by using new first_best_tac;
   640 
   641 * LaTeX document preparation: several changes of isabelle.sty (see
   642 lib/texinputs);
   643 
   644 
   645 *** Document preparation ***
   646 
   647 * formal comments (text blocks etc.) in new-style theories may now
   648 contain antiquotations of thm/prop/term/typ/text to be presented
   649 according to latex print mode; concrete syntax is like this:
   650 @{term[show_types] "f(x) = a + x"};
   651 
   652 * isatool mkdir provides easy setup of Isabelle session directories,
   653 including proper document sources;
   654 
   655 * generated LaTeX sources are now deleted after successful run
   656 (isatool document -c); may retain a copy somewhere else via -D option
   657 of isatool usedir;
   658 
   659 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   660 style files, achieving self-contained LaTeX sources and simplifying
   661 LaTeX debugging;
   662 
   663 * old-style theories now produce (crude) LaTeX output as well;
   664 
   665 * browser info session directories are now self-contained (may be put
   666 on WWW server seperately); improved graphs of nested sessions; removed
   667 graph for 'all sessions';
   668 
   669 * several improvements in isabelle style files; \isabellestyle{it}
   670 produces fake math mode output; \isamarkupheader is now \section by
   671 default; see lib/texinputs/isabelle.sty etc.;
   672 
   673 
   674 *** Isar ***
   675 
   676 * Isar/Pure: local results and corresponding term bindings are now
   677 subject to Hindley-Milner polymorphism (similar to ML); this
   678 accommodates incremental type-inference very nicely;
   679 
   680 * Isar/Pure: new derived language element 'obtain' supports
   681 generalized existence reasoning;
   682 
   683 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   684 support accumulation of results, without applying any rules yet;
   685 useful to collect intermediate results without explicit name
   686 references, and for use with transitivity rules with more than 2
   687 premises;
   688 
   689 * Isar/Pure: scalable support for case-analysis type proofs: new
   690 'case' language element refers to local contexts symbolically, as
   691 produced by certain proof methods; internally, case names are attached
   692 to theorems as "tags";
   693 
   694 * Isar/Pure: theory command 'hide' removes declarations from
   695 class/type/const name spaces;
   696 
   697 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   698 indicate potential overloading;
   699 
   700 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   701 
   702 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   703 "{a,b,c}" instead of {a,b,c};
   704 
   705 * Isar/Pure now provides its own version of intro/elim/dest
   706 attributes; useful for building new logics, but beware of confusion
   707 with the version in Provers/classical;
   708 
   709 * Isar/Pure: the local context of (non-atomic) goals is provided via
   710 case name 'antecedent';
   711 
   712 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   713 to the current context is now done automatically);
   714 
   715 * Isar/Pure: theory command 'method_setup' provides a simple interface
   716 for definining proof methods in ML;
   717 
   718 * Isar/Provers: intro/elim/dest attributes changed; renamed
   719 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   720 most cases, one should have to change intro!! to intro? only);
   721 replaced "delrule" by "rule del";
   722 
   723 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   724 'symmetric' attribute (the latter supercedes [RS sym]);
   725 
   726 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   727 method modifier); 'simp' method: 'only:' modifier removes loopers as
   728 well (including splits);
   729 
   730 * Isar/Provers: Simplifier and Classical methods now support all kind
   731 of modifiers used in the past, including 'cong', 'iff', etc.
   732 
   733 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   734 of Simplifier and Classical reasoner);
   735 
   736 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   737 now support named cases; major packages (inductive, datatype, primrec,
   738 recdef) support case names and properly name parameters;
   739 
   740 * Isar/HOL: new transitivity rules for substitution in inequalities --
   741 monotonicity conditions are extracted to be proven at end of
   742 calculations;
   743 
   744 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   745 method anyway;
   746 
   747 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   748 split_if split_if_asm; datatype package provides theorems foo.splits =
   749 foo.split foo.split_asm for each datatype;
   750 
   751 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   752 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   753 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   754 use "(cases (simplified))" method in proper proof texts);
   755 
   756 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   757 
   758 * Isar: names of theorems etc. may be natural numbers as well;
   759 
   760 * Isar: 'pr' command: optional arguments for goals_limit and
   761 ProofContext.prems_limit; no longer prints theory contexts, but only
   762 proof states;
   763 
   764 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   765 additional print modes to be specified; e.g. "pr(latex)" will print
   766 proof state according to the Isabelle LaTeX style;
   767 
   768 * Isar: improved support for emulating tactic scripts, including proof
   769 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   770 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   771 (for HOL datatypes);
   772 
   773 * Isar: simplified (more robust) goal selection of proof methods: 1st
   774 goal, all goals, or explicit goal specifier (tactic emulation); thus
   775 'proof method scripts' have to be in depth-first order;
   776 
   777 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   778 
   779 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   780 should instead use individual commands for printing items
   781 (print_commands, print_methods etc.);
   782 
   783 * Isar: added 'nothing' --- the empty list of theorems;
   784 
   785 
   786 *** HOL ***
   787 
   788 * HOL/MicroJava: formalization of a fragment of Java, together with a
   789 corresponding virtual machine and a specification of its bytecode
   790 verifier and a lightweight bytecode verifier, including proofs of
   791 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   792 Cornelia Pusch (see also the homepage of project Bali at
   793 http://isabelle.in.tum.de/Bali/);
   794 
   795 * HOL/Algebra: new theory of rings and univariate polynomials, by
   796 Clemens Ballarin;
   797 
   798 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   799 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   800 Rasmussen;
   801 
   802 * HOL/Lattice: fundamental concepts of lattice theory and order
   803 structures, including duals, properties of bounds versus algebraic
   804 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   805 Theorem for complete lattices etc.; may also serve as a demonstration
   806 for abstract algebraic reasoning using axiomatic type classes, and
   807 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   808 
   809 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   810 von Oheimb;
   811 
   812 * HOL/IMPP: extension of IMP with local variables and mutually
   813 recursive procedures, by David von Oheimb;
   814 
   815 * HOL/Lambda: converted into new-style theory and document;
   816 
   817 * HOL/ex/Multiquote: example of multiple nested quotations and
   818 anti-quotations -- basically a generalized version of de-Bruijn
   819 representation; very useful in avoiding lifting of operations;
   820 
   821 * HOL/record: added general record equality rule to simpset; fixed
   822 select-update simplification procedure to handle extended records as
   823 well; admit "r" as field name;
   824 
   825 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   826 other numeric types and also as the identity of groups, rings, etc.;
   827 
   828 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   829 Types nat and int belong to this axclass;
   830 
   831 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   832    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   833    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   834   two terms #m*u and #n*u are replaced by #(m+n)*u
   835     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   836   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   837     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   838 
   839 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   840 powerful prover for predicate logic but knows nothing of clasets; see
   841 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   842 
   843 * HOL: new version of "case_tac" subsumes both boolean case split and
   844 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   845 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   846 
   847 * HOL: simplification no longer dives into case-expressions: only the
   848 selector expression is simplified, but not the remaining arms; to
   849 enable full simplification of case-expressions for datatype t, you may
   850 remove t.weak_case_cong from the simpset, either globally (Delcongs
   851 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   852 
   853 * HOL/recdef: the recursion equations generated by 'recdef' for
   854 function 'f' are now called f.simps instead of f.rules; if all
   855 termination conditions are proved automatically, these simplification
   856 rules are added to the simpset, as in primrec; rules may be named
   857 individually as well, resulting in a separate list of theorems for
   858 each equation;
   859 
   860 * HOL/While is a new theory that provides a while-combinator. It
   861 permits the definition of tail-recursive functions without the
   862 provision of a termination measure. The latter is necessary once the
   863 invariant proof rule for while is applied.
   864 
   865 * HOL: new (overloaded) notation for the set of elements below/above
   866 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   867 
   868 * HOL: theorems impI, allI, ballI bound as "strip";
   869 
   870 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   871 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   872 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   873 
   874 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   875 
   876 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   877 main HOL, but was unused);
   878 
   879 * HOL: fewer consts declared as global (e.g. have to refer to
   880 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   881 
   882 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   883 in case of overlap with user translations (e.g. judgements over
   884 tuples); (note that the underlying logical represenation is still
   885 bogus);
   886 
   887 
   888 *** ZF ***
   889 
   890 * ZF: simplification automatically cancels common terms in arithmetic
   891 expressions over nat and int;
   892 
   893 * ZF: new treatment of nat to minimize type-checking: all operators
   894 coerce their operands to a natural number using the function natify,
   895 making the algebraic laws unconditional;
   896 
   897 * ZF: as above, for int: operators coerce their operands to an integer
   898 using the function intify;
   899 
   900 * ZF: the integer library now contains many of the usual laws for the
   901 orderings, including $<=, and monotonicity laws for $+ and $*;
   902 
   903 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   904 simplification;
   905 
   906 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   907 to the simplifier and classical reasoner simultaneously;
   908 
   909 
   910 *** General ***
   911 
   912 * Provers: blast_tac now handles actual object-logic rules as
   913 assumptions; note that auto_tac uses blast_tac internally as well;
   914 
   915 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   916 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   917 
   918 * Provers: delrules now handles destruct rules as well (no longer need
   919 explicit make_elim);
   920 
   921 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   922   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   923 use instead the strong form,
   924   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   925 in HOL, FOL and ZF the function cla_make_elim will create such rules
   926 from destruct-rules;
   927 
   928 * Provers: Simplifier.easy_setup provides a fast path to basic
   929 Simplifier setup for new object-logics;
   930 
   931 * Pure: AST translation rules no longer require constant head on LHS;
   932 
   933 * Pure: improved name spaces: ambiguous output is qualified; support
   934 for hiding of names;
   935 
   936 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   937 XSYMBOL_HOME; no longer need to do manual configuration in most
   938 situations;
   939 
   940 * system: compression of ML heaps images may now be controlled via -c
   941 option of isabelle and isatool usedir (currently only observed by
   942 Poly/ML);
   943 
   944 * system: isatool installfonts may handle X-Symbol fonts as well (very
   945 useful for remote X11);
   946 
   947 * system: provide TAGS file for Isabelle sources;
   948 
   949 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   950 order;
   951 
   952 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   953 timing flag supersedes proof_timing and Toplevel.trace;
   954 
   955 * ML: new combinators |>> and |>>> for incremental transformations
   956 with secondary results (e.g. certain theory extensions):
   957 
   958 * ML: PureThy.add_defs gets additional argument to indicate potential
   959 overloading (usually false);
   960 
   961 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   962 results;
   963 
   964 
   965 
   966 New in Isabelle99 (October 1999)
   967 --------------------------------
   968 
   969 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   970 
   971 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   972 are no longer simplified.  (This allows the simplifier to unfold recursive
   973 functional programs.)  To restore the old behaviour, declare
   974 
   975     Delcongs [if_weak_cong];
   976 
   977 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   978 complement;
   979 
   980 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   981 
   982 * HOL/datatype: mutual_induct_tac no longer exists --
   983   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   984 
   985 * HOL/typedef: fixed type inference for representing set; type
   986 arguments now have to occur explicitly on the rhs as type constraints;
   987 
   988 * ZF: The con_defs part of an inductive definition may no longer refer
   989 to constants declared in the same theory;
   990 
   991 * HOL, ZF: the function mk_cases, generated by the inductive
   992 definition package, has lost an argument.  To simplify its result, it
   993 uses the default simpset instead of a supplied list of theorems.
   994 
   995 * HOL/List: the constructors of type list are now Nil and Cons;
   996 
   997 * Simplifier: the type of the infix ML functions
   998         setSSolver addSSolver setSolver addSolver
   999 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1000 for packaging solvers. A solver is created via
  1001         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1002 where the string argument is only a comment.
  1003 
  1004 
  1005 *** Proof tools ***
  1006 
  1007 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1008 decision procedure for linear arithmetic. Currently it is used for
  1009 types `nat', `int', and `real' in HOL (see below); it can, should and
  1010 will be instantiated for other types and logics as well.
  1011 
  1012 * The simplifier now accepts rewrite rules with flexible heads, eg
  1013      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1014   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1015   matching.
  1016 
  1017 
  1018 *** General ***
  1019 
  1020 * New Isabelle/Isar subsystem provides an alternative to traditional
  1021 tactical theorem proving; together with the ProofGeneral/isar user
  1022 interface it offers an interactive environment for developing human
  1023 readable proof documents (Isar == Intelligible semi-automated
  1024 reasoning); for further information see isatool doc isar-ref,
  1025 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1026 
  1027 * improved and simplified presentation of theories: better HTML markup
  1028 (including colors), graph views in several sizes; isatool usedir now
  1029 provides a proper interface for user theories (via -P option); actual
  1030 document preparation based on (PDF)LaTeX is available as well (for
  1031 new-style theories only); see isatool doc system for more information;
  1032 
  1033 * native support for Proof General, both for classic Isabelle and
  1034 Isabelle/Isar;
  1035 
  1036 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1037 using the graph browser tool;
  1038 
  1039 * Isabelle manuals now also available as PDF;
  1040 
  1041 * theory loader rewritten from scratch (may not be fully
  1042 bug-compatible); old loadpath variable has been replaced by show_path,
  1043 add_path, del_path, reset_path functions; new operations such as
  1044 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1045 isatool doc ref);
  1046 
  1047 * improved isatool install: option -k creates KDE application icon,
  1048 option -p DIR installs standalone binaries;
  1049 
  1050 * added ML_PLATFORM setting (useful for cross-platform installations);
  1051 more robust handling of platform specific ML images for SML/NJ;
  1052 
  1053 * the settings environment is now statically scoped, i.e. it is never
  1054 created again in sub-processes invoked from isabelle, isatool, or
  1055 Isabelle;
  1056 
  1057 * path element specification '~~' refers to '$ISABELLE_HOME';
  1058 
  1059 * in locales, the "assumes" and "defines" parts may be omitted if
  1060 empty;
  1061 
  1062 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1063 long arrows);
  1064 
  1065 * new print_mode "HTML";
  1066 
  1067 * new flag show_tags controls display of tags of theorems (which are
  1068 basically just comments that may be attached by some tools);
  1069 
  1070 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1071 mode and goal output format:
  1072 
  1073 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1074 244c244
  1075 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1076 ---
  1077 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1078 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1079 181c181
  1080 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1081 ---
  1082 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1083 
  1084 * function bind_thms stores lists of theorems (cf. bind_thm);
  1085 
  1086 * new shorthand tactics ftac, eatac, datac, fatac;
  1087 
  1088 * qed (and friends) now accept "" as result name; in that case the
  1089 theorem is not stored, but proper checks and presentation of the
  1090 result still apply;
  1091 
  1092 * theorem database now also indexes constants "Trueprop", "all",
  1093 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1094 
  1095 
  1096 *** HOL ***
  1097 
  1098 ** HOL arithmetic **
  1099 
  1100 * There are now decision procedures for linear arithmetic over nat and
  1101 int:
  1102 
  1103 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1104 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1105 are treated as atomic; subformulae not involving type `nat' or `int'
  1106 are ignored; quantified subformulae are ignored unless they are
  1107 positive universal or negative existential. The tactic has to be
  1108 invoked by hand and can be a little bit slow. In particular, the
  1109 running time is exponential in the number of occurrences of `min' and
  1110 `max', and `-' on `nat'.
  1111 
  1112 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1113 (negated) (in)equalities among the premises and the conclusion into
  1114 account (i.e. no compound formulae) and does not know about `min' and
  1115 `max', and `-' on `nat'. It is fast and is used automatically by the
  1116 simplifier.
  1117 
  1118 NB: At the moment, these decision procedures do not cope with mixed
  1119 nat/int formulae where the two parts interact, such as `m < n ==>
  1120 int(m) < int(n)'.
  1121 
  1122 * HOL/Numeral provides a generic theory of numerals (encoded
  1123 efficiently as bit strings); setup for types nat/int/real is in place;
  1124 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1125 int, existing theories and proof scripts may require a few additional
  1126 type constraints;
  1127 
  1128 * integer division and remainder can now be performed on constant
  1129 arguments;
  1130 
  1131 * many properties of integer multiplication, division and remainder
  1132 are now available;
  1133 
  1134 * An interface to the Stanford Validity Checker (SVC) is available through the
  1135 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1136 are proved automatically.  SVC must be installed separately, and its results
  1137 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1138 invocation of the underlying oracle).  For SVC see
  1139   http://verify.stanford.edu/SVC
  1140 
  1141 * IsaMakefile: the HOL-Real target now builds an actual image;
  1142 
  1143 
  1144 ** HOL misc **
  1145 
  1146 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1147 (in Isabelle/Isar) -- by Gertrud Bauer;
  1148 
  1149 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1150 analysis for assembly languages with subtypes;
  1151 
  1152 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1153 -- avoids syntactic ambiguities and treats state, transition, and
  1154 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1155 changed syntax and (many) tactics;
  1156 
  1157 * HOL/inductive: Now also handles more general introduction rules such
  1158   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1159   theorems are now maintained within the theory (maintained via the
  1160   "mono" attribute);
  1161 
  1162 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1163   (using function types) such as
  1164 
  1165   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1166 
  1167 * HOL/record: record_simproc (part of the default simpset) takes care
  1168 of selectors applied to updated records; record_split_tac is no longer
  1169 part of the default claset; update_defs may now be removed from the
  1170 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1171 
  1172   claset_ref () := claset() addSWrapper record_split_wrapper;
  1173   Delsimprocs [record_simproc]
  1174 
  1175 * HOL/typedef: fixed type inference for representing set; type
  1176 arguments now have to occur explicitly on the rhs as type constraints;
  1177 
  1178 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1179 names rather than an ML expression;
  1180 
  1181 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1182 supplied later.  Program schemes can be defined, such as
  1183     "While B C s = (if B s then While B C (C s) else s)"
  1184 where the well-founded relation can be chosen after B and C have been given.
  1185 
  1186 * HOL/List: the constructors of type list are now Nil and Cons;
  1187 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1188 course, ML tools referring to List.list.op # etc. have to be adapted;
  1189 
  1190 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1191 disabled by default; run isabelle with option -m HOL to get back to
  1192 the original Gordon/HOL-style output;
  1193 
  1194 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1195 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1196 
  1197 * HOL basic syntax simplified (more orthogonal): all variants of
  1198 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1199 Eps operator is provided as well: "SOME x. P[x]";
  1200 
  1201 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1202 
  1203 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1204 thus available for user theories;
  1205 
  1206 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1207 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1208 time;
  1209 
  1210 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1211 several times and then mp;
  1212 
  1213 
  1214 *** LK ***
  1215 
  1216 * the notation <<...>> is now available as a notation for sequences of
  1217 formulas;
  1218 
  1219 * the simplifier is now installed
  1220 
  1221 * the axiom system has been generalized (thanks to Soren Heilmann)
  1222 
  1223 * the classical reasoner now has a default rule database
  1224 
  1225 
  1226 *** ZF ***
  1227 
  1228 * new primrec section allows primitive recursive functions to be given
  1229 directly (as in HOL) over datatypes and the natural numbers;
  1230 
  1231 * new tactics induct_tac and exhaust_tac for induction (or case
  1232 analysis) over datatypes and the natural numbers;
  1233 
  1234 * the datatype declaration of type T now defines the recursor T_rec;
  1235 
  1236 * simplification automatically does freeness reasoning for datatype
  1237 constructors;
  1238 
  1239 * automatic type-inference, with AddTCs command to insert new
  1240 type-checking rules;
  1241 
  1242 * datatype introduction rules are now added as Safe Introduction rules
  1243 to the claset;
  1244 
  1245 * the syntax "if P then x else y" is now available in addition to
  1246 if(P,x,y);
  1247 
  1248 
  1249 *** Internal programming interfaces ***
  1250 
  1251 * tuned simplifier trace output; new flag debug_simp;
  1252 
  1253 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1254 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1255 
  1256 * AxClass.axclass_tac lost the theory argument;
  1257 
  1258 * tuned current_goals_markers semantics: begin / end goal avoids
  1259 printing empty lines;
  1260 
  1261 * removed prs and prs_fn hook, which was broken because it did not
  1262 include \n in its semantics, forcing writeln to add one
  1263 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1264 string -> unit if you really want to output text without newline;
  1265 
  1266 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1267 plain output, interface builders may have to enable 'isabelle_font'
  1268 mode to get Isabelle font glyphs as before;
  1269 
  1270 * refined token_translation interface; INCOMPATIBILITY: output length
  1271 now of type real instead of int;
  1272 
  1273 * theory loader actions may be traced via new ThyInfo.add_hook
  1274 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1275 your own database of information attached to *whole* theories -- as
  1276 opposed to intra-theory data slots offered via TheoryDataFun;
  1277 
  1278 * proper handling of dangling sort hypotheses (at last!);
  1279 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1280 extra sort hypotheses that can be witnessed from the type signature;
  1281 the force_strip_shyps flag is gone, any remaining shyps are simply
  1282 left in the theorem (with a warning issued by strip_shyps_warning);
  1283 
  1284 
  1285 
  1286 New in Isabelle98-1 (October 1998)
  1287 ----------------------------------
  1288 
  1289 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1290 
  1291 * several changes of automated proof tools;
  1292 
  1293 * HOL: major changes to the inductive and datatype packages, including
  1294 some minor incompatibilities of theory syntax;
  1295 
  1296 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1297 called `inj_on';
  1298 
  1299 * HOL: removed duplicate thms in Arith:
  1300   less_imp_add_less  should be replaced by  trans_less_add1
  1301   le_imp_add_le      should be replaced by  trans_le_add1
  1302 
  1303 * HOL: unary minus is now overloaded (new type constraints may be
  1304 required);
  1305 
  1306 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1307 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1308 now taken as an integer constant.
  1309 
  1310 * Pure: ML function 'theory_of' renamed to 'theory';
  1311 
  1312 
  1313 *** Proof tools ***
  1314 
  1315 * Simplifier:
  1316   1. Asm_full_simp_tac is now more aggressive.
  1317      1. It will sometimes reorient premises if that increases their power to
  1318         simplify.
  1319      2. It does no longer proceed strictly from left to right but may also
  1320         rotate premises to achieve further simplification.
  1321      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1322      old Asm_full_simp_tac in that it does not rotate premises.
  1323   2. The simplifier now knows a little bit about nat-arithmetic.
  1324 
  1325 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1326 allows for selected deletion of wrappers, by introduction of names for
  1327 wrapper functionals.  This implies that addbefore, addSbefore,
  1328 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1329 and that adding two tactics with the same name overwrites the first
  1330 one (emitting a warning).
  1331   type wrapper = (int -> tactic) -> (int -> tactic)
  1332   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1333   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1334   delWrapper, delSWrapper: claset *  string            -> claset
  1335   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1336 
  1337 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1338 semantics; addbefore now affects only the unsafe part of step_tac
  1339 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1340 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1341 by Force_tac;
  1342 
  1343 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1344 compWrapper; added safe wrapper (and access functions for it);
  1345 
  1346 * HOL/split_all_tac is now much faster and fails if there is nothing
  1347 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1348 and the names of the automatically generated variables have changed.
  1349 split_all_tac has moved within claset() from unsafe wrappers to safe
  1350 wrappers, which means that !!-bound variables are split much more
  1351 aggressively, and safe_tac and clarify_tac now split such variables.
  1352 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1353 Note: the same holds for record_split_tac, which does the job of
  1354 split_all_tac for record fields.
  1355 
  1356 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1357 permanently to the default simpset using Addsplits just like
  1358 Addsimps. They can be removed via Delsplits just like
  1359 Delsimps. Lower-case versions are also available.
  1360 
  1361 * HOL/Simplifier: The rule split_if is now part of the default
  1362 simpset. This means that the simplifier will eliminate all occurrences
  1363 of if-then-else in the conclusion of a goal. To prevent this, you can
  1364 either remove split_if completely from the default simpset by
  1365 `Delsplits [split_if]' or remove it in a specific call of the
  1366 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1367 other case splitting rules to/from the default simpset: every datatype
  1368 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1369 t is the name of the datatype).
  1370 
  1371 * Classical reasoner / Simplifier combination: new force_tac (and
  1372 derivatives Force_tac, force) combines rewriting and classical
  1373 reasoning (and whatever other tools) similarly to auto_tac, but is
  1374 aimed to solve the given subgoal completely.
  1375 
  1376 
  1377 *** General ***
  1378 
  1379 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1380 and `goalw': the theory is no longer needed as an explicit argument -
  1381 the current theory context is used; assumptions are no longer returned
  1382 at the ML-level unless one of them starts with ==> or !!; it is
  1383 recommended to convert to these new commands using isatool fixgoal
  1384 (backup your sources first!);
  1385 
  1386 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1387 the current theory context, and 'theory' to lookup stored theories;
  1388 
  1389 * new theory section 'locale' for declaring constants, assumptions and
  1390 definitions that have local scope;
  1391 
  1392 * new theory section 'nonterminals' for purely syntactic types;
  1393 
  1394 * new theory section 'setup' for generic ML setup functions
  1395 (e.g. package initialization);
  1396 
  1397 * the distribution now includes Isabelle icons: see
  1398 lib/logo/isabelle-{small,tiny}.xpm;
  1399 
  1400 * isatool install - install binaries with absolute references to
  1401 ISABELLE_HOME/bin;
  1402 
  1403 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1404 
  1405 * print mode 'emacs' reserved for Isamode;
  1406 
  1407 * support multiple print (ast) translations per constant name;
  1408 
  1409 * theorems involving oracles are now printed with a suffixed [!];
  1410 
  1411 
  1412 *** HOL ***
  1413 
  1414 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1415 
  1416 * HOL/inductive package reorganized and improved: now supports mutual
  1417 definitions such as
  1418 
  1419   inductive EVEN ODD
  1420     intrs
  1421       null "0 : EVEN"
  1422       oddI "n : EVEN ==> Suc n : ODD"
  1423       evenI "n : ODD ==> Suc n : EVEN"
  1424 
  1425 new theorem list "elims" contains an elimination rule for each of the
  1426 recursive sets; inductive definitions now handle disjunctive premises
  1427 correctly (also ZF);
  1428 
  1429 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1430 "mutual_induct" no longer exists - the induction rule is always
  1431 contained in "induct";
  1432 
  1433 
  1434 * HOL/datatype package re-implemented and greatly improved: now
  1435 supports mutually recursive datatypes such as
  1436 
  1437   datatype
  1438     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1439             | SUM ('a aexp) ('a aexp)
  1440             | DIFF ('a aexp) ('a aexp)
  1441             | NUM 'a
  1442   and
  1443     'a bexp = LESS ('a aexp) ('a aexp)
  1444             | AND ('a bexp) ('a bexp)
  1445             | OR ('a bexp) ('a bexp)
  1446 
  1447 as well as indirectly recursive datatypes such as
  1448 
  1449   datatype
  1450     ('a, 'b) term = Var 'a
  1451                   | App 'b ((('a, 'b) term) list)
  1452 
  1453 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1454 induction on mutually / indirectly recursive datatypes.
  1455 
  1456 Primrec equations are now stored in theory and can be accessed via
  1457 <function_name>.simps.
  1458 
  1459 INCOMPATIBILITIES:
  1460 
  1461   - Theories using datatypes must now have theory Datatype as an
  1462     ancestor.
  1463   - The specific <typename>.induct_tac no longer exists - use the
  1464     generic induct_tac instead.
  1465   - natE has been renamed to nat.exhaust - use exhaust_tac
  1466     instead of res_inst_tac ... natE. Note that the variable
  1467     names in nat.exhaust differ from the names in natE, this
  1468     may cause some "fragile" proofs to fail.
  1469   - The theorems split_<typename>_case and split_<typename>_case_asm
  1470     have been renamed to <typename>.split and <typename>.split_asm.
  1471   - Since default sorts of type variables are now handled correctly,
  1472     some datatype definitions may have to be annotated with explicit
  1473     sort constraints.
  1474   - Primrec definitions no longer require function name and type
  1475     of recursive argument.
  1476 
  1477 Consider using isatool fixdatatype to adapt your theories and proof
  1478 scripts to the new package (backup your sources first!).
  1479 
  1480 
  1481 * HOL/record package: considerably improved implementation; now
  1482 includes concrete syntax for record types, terms, updates; theorems
  1483 for surjective pairing and splitting !!-bound record variables; proof
  1484 support is as follows:
  1485 
  1486   1) standard conversions (selectors or updates applied to record
  1487 constructor terms) are part of the standard simpset;
  1488 
  1489   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1490 made part of standard simpset and claset via addIffs;
  1491 
  1492   3) a tactic for record field splitting (record_split_tac) is part of
  1493 the standard claset (addSWrapper);
  1494 
  1495 To get a better idea about these rules you may retrieve them via
  1496 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1497 the name of your record type.
  1498 
  1499 The split tactic 3) conceptually simplifies by the following rule:
  1500 
  1501   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1502 
  1503 Thus any record variable that is bound by meta-all will automatically
  1504 blow up into some record constructor term, consequently the
  1505 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1506 solve record problems automatically.
  1507 
  1508 
  1509 * reorganized the main HOL image: HOL/Integ and String loaded by
  1510 default; theory Main includes everything;
  1511 
  1512 * automatic simplification of integer sums and comparisons, using cancellation;
  1513 
  1514 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1515 
  1516 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1517 
  1518 * many new identities for unions, intersections, set difference, etc.;
  1519 
  1520 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1521 called split_if, split_split, split_sum_case and split_nat_case (to go
  1522 with add/delsplits);
  1523 
  1524 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1525 (?x::unit) = (); this is made part of the default simpset, which COULD
  1526 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1527 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1528 unit_abs_eta_conv is added in order to counter the effect of
  1529 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1530 %u.f();
  1531 
  1532 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1533 makes more sense);
  1534 
  1535 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1536   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1537   disjointness reasoning but breaking a few old proofs.
  1538 
  1539 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1540 to 'converse' from 'inverse' (for compatibility with ZF and some
  1541 literature);
  1542 
  1543 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1544 the well-founded relation;
  1545 
  1546 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1547     Compl A.  The "Compl" syntax remains available as input syntax for this
  1548     release ONLY.
  1549 
  1550 * HOL/Update: new theory of function updates:
  1551     f(a:=b) == %x. if x=a then b else f x
  1552 may also be iterated as in f(a:=b,c:=d,...);
  1553 
  1554 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1555 
  1556 * HOL/List:
  1557   - new function list_update written xs[i:=v] that updates the i-th
  1558     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1559   - new function `upt' written [i..j(] which generates the list
  1560     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1561     bound write [i..j], which is a shorthand for [i..j+1(].
  1562   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1563 
  1564 * HOL/Arith:
  1565   - removed 'pred' (predecessor) function;
  1566   - generalized some theorems about n-1;
  1567   - many new laws about "div" and "mod";
  1568   - new laws about greatest common divisors (see theory ex/Primes);
  1569 
  1570 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1571 instead of "inverse";
  1572 
  1573 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1574   of the multiset ordering;
  1575 
  1576 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1577   (not included by default);
  1578 
  1579 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1580 
  1581 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1582   programs, i.e. different program variables may have different types.
  1583 
  1584 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1585   [previously, this check worked only if the rewrite rule was unconditional]
  1586   Now rew can involve either definitions or equalities (either == or =).
  1587 
  1588 
  1589 *** ZF ***
  1590 
  1591 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1592   only the theorems proved on ZF.ML;
  1593 
  1594 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1595   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1596   disjointness reasoning but breaking a few old proofs.
  1597 
  1598 * ZF/Update: new theory of function updates
  1599     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1600   may also be iterated as in f(a:=b,c:=d,...);
  1601 
  1602 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1603 
  1604 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1605   [previously, this check worked only if the rewrite rule was unconditional]
  1606   Now rew can involve either definitions or equalities (either == or =).
  1607 
  1608 * case_tac provided for compatibility with HOL
  1609     (like the old excluded_middle_tac, but with subgoals swapped)
  1610 
  1611 
  1612 *** Internal programming interfaces ***
  1613 
  1614 * Pure: several new basic modules made available for general use, see
  1615 also src/Pure/README;
  1616 
  1617 * improved the theory data mechanism to support encapsulation (data
  1618 kind name replaced by private Object.kind, acting as authorization
  1619 key); new type-safe user interface via functor TheoryDataFun; generic
  1620 print_data function becomes basically useless;
  1621 
  1622 * removed global_names compatibility flag -- all theory declarations
  1623 are qualified by default;
  1624 
  1625 * module Pure/Syntax now offers quote / antiquote translation
  1626 functions (useful for Hoare logic etc. with implicit dependencies);
  1627 see HOL/ex/Antiquote for an example use;
  1628 
  1629 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1630 cterm -> thm;
  1631 
  1632 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1633 subgoal;
  1634 
  1635 * Display.print_goals function moved to Locale.print_goals;
  1636 
  1637 * standard print function for goals supports current_goals_markers
  1638 variable for marking begin of proof, end of proof, start of goal; the
  1639 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1640 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1641 for example;
  1642 
  1643 
  1644 
  1645 New in Isabelle98 (January 1998)
  1646 --------------------------------
  1647 
  1648 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1649 
  1650 * changed lexical syntax of terms / types: dots made part of long
  1651 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1652 
  1653 * simpset (and claset) reference variable replaced by functions
  1654 simpset / simpset_ref;
  1655 
  1656 * no longer supports theory aliases (via merge) and non-trivial
  1657 implicit merge of thms' signatures;
  1658 
  1659 * most internal names of constants changed due to qualified names;
  1660 
  1661 * changed Pure/Sequence interface (see Pure/seq.ML);
  1662 
  1663 
  1664 *** General Changes ***
  1665 
  1666 * hierachically structured name spaces (for consts, types, axms, thms
  1667 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1668 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1669 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1670 long_names for fully qualified output names; NOTE: ML programs
  1671 (special tactics, packages etc.) referring to internal names may have
  1672 to be adapted to cope with fully qualified names; in case of severe
  1673 backward campatibility problems try setting 'global_names' at compile
  1674 time to have enrything declared within a flat name space; one may also
  1675 fine tune name declarations in theories via the 'global' and 'local'
  1676 section;
  1677 
  1678 * reimplemented the implicit simpset and claset using the new anytype
  1679 data filed in signatures; references simpset:simpset ref etc. are
  1680 replaced by functions simpset:unit->simpset and
  1681 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1682 to patch your ML files accordingly;
  1683 
  1684 * HTML output now includes theory graph data for display with Java
  1685 applet or isatool browser; data generated automatically via isatool
  1686 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1687 
  1688 * defs may now be conditional; improved rewrite_goals_tac to handle
  1689 conditional equations;
  1690 
  1691 * defs now admits additional type arguments, using TYPE('a) syntax;
  1692 
  1693 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1694 creates a new theory node; implicit merge of thms' signatures is
  1695 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1696 transfer:theory->thm->thm in (rare) cases;
  1697 
  1698 * improved handling of draft signatures / theories; draft thms (and
  1699 ctyps, cterms) are automatically promoted to real ones;
  1700 
  1701 * slightly changed interfaces for oracles: admit many per theory, named
  1702 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1703 
  1704 * print_goals: optional output of const types (set show_consts and
  1705 show_types);
  1706 
  1707 * improved output of warnings (###) and errors (***);
  1708 
  1709 * subgoal_tac displays a warning if the new subgoal has type variables;
  1710 
  1711 * removed old README and Makefiles;
  1712 
  1713 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1714 
  1715 * removed obsolete init_pps and init_database;
  1716 
  1717 * deleted the obsolete tactical STATE, which was declared by
  1718     fun STATE tacfun st = tacfun st st;
  1719 
  1720 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1721 (which abbreviates $HOME);
  1722 
  1723 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1724 use isatool fixseq to adapt your ML programs (this works for fully
  1725 qualified references to the Sequence structure only!);
  1726 
  1727 * use_thy no longer requires writable current directory; it always
  1728 reloads .ML *and* .thy file, if either one is out of date;
  1729 
  1730 
  1731 *** Classical Reasoner ***
  1732 
  1733 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1734 tactics that use classical reasoning to simplify a subgoal without
  1735 splitting it into several subgoals;
  1736 
  1737 * Safe_tac: like safe_tac but uses the default claset;
  1738 
  1739 
  1740 *** Simplifier ***
  1741 
  1742 * added simplification meta rules:
  1743     (asm_)(full_)simplify: simpset -> thm -> thm;
  1744 
  1745 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1746 logics (again);
  1747 
  1748 * added prems argument to simplification procedures;
  1749 
  1750 * HOL, FOL, ZF: added infix function `addsplits':
  1751   instead of `<simpset> setloop (split_tac <thms>)'
  1752   you can simply write `<simpset> addsplits <thms>'
  1753 
  1754 
  1755 *** Syntax ***
  1756 
  1757 * TYPE('a) syntax for type reflection terms;
  1758 
  1759 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1760 
  1761 * pretty printer: changed order of mixfix annotation preference (again!);
  1762 
  1763 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1764 
  1765 
  1766 *** HOL ***
  1767 
  1768 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1769   with `addloop' of the simplifier to faciliate case splitting in premises.
  1770 
  1771 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1772 
  1773 * HOL/Auth: new protocol proofs including some for the Internet
  1774   protocol TLS;
  1775 
  1776 * HOL/Map: new theory of `maps' a la VDM;
  1777 
  1778 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1779 cancelling out common nat summands from =, <, <= (in)equalities, or
  1780 differences; simplification procedures nat_cancel_factor for
  1781 cancelling common factor from =, <, <= (in)equalities over natural
  1782 sums; nat_cancel contains both kinds of procedures, it is installed by
  1783 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1784 
  1785 * HOL/simplifier: terms of the form
  1786   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1787   are rewritten to
  1788   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1789   and those of the form
  1790   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1791   are rewritten to
  1792   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1793 
  1794 * HOL/datatype
  1795   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1796 
  1797   P(t_case f1 ... fn x) =
  1798      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1799         ...
  1800        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1801      )
  1802 
  1803   and a theorem `split_t_case_asm' of the form
  1804 
  1805   P(t_case f1 ... fn x) =
  1806     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1807         ...
  1808        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1809      )
  1810   which can be added to a simpset via `addsplits'. The existing theorems
  1811   expand_list_case and expand_option_case have been renamed to
  1812   split_list_case and split_option_case.
  1813 
  1814 * HOL/Arithmetic:
  1815   - `pred n' is automatically converted to `n-1'.
  1816     Users are strongly encouraged not to use `pred' any longer,
  1817     because it will disappear altogether at some point.
  1818   - Users are strongly encouraged to write "0 < n" rather than
  1819     "n ~= 0". Theorems and proof tools have been modified towards this
  1820     `standard'.
  1821 
  1822 * HOL/Lists:
  1823   the function "set_of_list" has been renamed "set" (and its theorems too);
  1824   the function "nth" now takes its arguments in the reverse order and
  1825   has acquired the infix notation "!" as in "xs!n".
  1826 
  1827 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1828 
  1829 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1830   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1831 
  1832 * HOL/record: extensible records with schematic structural subtyping
  1833 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1834 still lacks various theorems and concrete record syntax;
  1835 
  1836 
  1837 *** HOLCF ***
  1838 
  1839 * removed "axioms" and "generated by" sections;
  1840 
  1841 * replaced "ops" section by extended "consts" section, which is capable of
  1842   handling the continuous function space "->" directly;
  1843 
  1844 * domain package:
  1845   . proves theorems immediately and stores them in the theory,
  1846   . creates hierachical name space,
  1847   . now uses normal mixfix annotations (instead of cinfix...),
  1848   . minor changes to some names and values (for consistency),
  1849   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1850   . separator between mutual domain defs: changed "," to "and",
  1851   . improved handling of sort constraints;  now they have to
  1852     appear on the left-hand side of the equations only;
  1853 
  1854 * fixed LAM <x,y,zs>.b syntax;
  1855 
  1856 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1857 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1858 
  1859 
  1860 *** FOL and ZF ***
  1861 
  1862 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1863   with `addloop' of the simplifier to faciliate case splitting in premises.
  1864 
  1865 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1866 in HOL, they strip ALL and --> from proved theorems;
  1867 
  1868 
  1869 
  1870 New in Isabelle94-8 (May 1997)
  1871 ------------------------------
  1872 
  1873 *** General Changes ***
  1874 
  1875 * new utilities to build / run / maintain Isabelle etc. (in parts
  1876 still somewhat experimental); old Makefiles etc. still functional;
  1877 
  1878 * new 'Isabelle System Manual';
  1879 
  1880 * INSTALL text, together with ./configure and ./build scripts;
  1881 
  1882 * reimplemented type inference for greater efficiency, better error
  1883 messages and clean internal interface;
  1884 
  1885 * prlim command for dealing with lots of subgoals (an easier way of
  1886 setting goals_limit);
  1887 
  1888 
  1889 *** Syntax ***
  1890 
  1891 * supports alternative (named) syntax tables (parser and pretty
  1892 printer); internal interface is provided by add_modesyntax(_i);
  1893 
  1894 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1895 be used in conjunction with the Isabelle symbol font; uses the
  1896 "symbols" syntax table;
  1897 
  1898 * added token_translation interface (may translate name tokens in
  1899 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1900 the current print_mode); IMPORTANT: user print translation functions
  1901 are responsible for marking newly introduced bounds
  1902 (Syntax.mark_boundT);
  1903 
  1904 * token translations for modes "xterm" and "xterm_color" that display
  1905 names in bold, underline etc. or colors (which requires a color
  1906 version of xterm);
  1907 
  1908 * infixes may now be declared with names independent of their syntax;
  1909 
  1910 * added typed_print_translation (like print_translation, but may
  1911 access type of constant);
  1912 
  1913 
  1914 *** Classical Reasoner ***
  1915 
  1916 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1917 some limitations.  Blast_tac...
  1918   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1919   + ignores elimination rules that don't have the correct format
  1920         (the conclusion MUST be a formula variable)
  1921   + ignores types, which can make HOL proofs fail
  1922   + rules must not require higher-order unification, e.g. apply_type in ZF
  1923     [message "Function Var's argument not a bound variable" relates to this]
  1924   + its proof strategy is more general but can actually be slower
  1925 
  1926 * substitution with equality assumptions no longer permutes other
  1927 assumptions;
  1928 
  1929 * minor changes in semantics of addafter (now called addaltern); renamed
  1930 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1931 (and access functions for it);
  1932 
  1933 * improved combination of classical reasoner and simplifier:
  1934   + functions for handling clasimpsets
  1935   + improvement of addss: now the simplifier is called _after_ the
  1936     safe steps.
  1937   + safe variant of addss called addSss: uses safe simplifications
  1938     _during_ the safe steps. It is more complete as it allows multiple
  1939     instantiations of unknowns (e.g. with slow_tac).
  1940 
  1941 *** Simplifier ***
  1942 
  1943 * added interface for simplification procedures (functions that
  1944 produce *proven* rewrite rules on the fly, depending on current
  1945 redex);
  1946 
  1947 * ordering on terms as parameter (used for ordered rewriting);
  1948 
  1949 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1950 
  1951 * the solver is now split into a safe and an unsafe part.
  1952 This should be invisible for the normal user, except that the
  1953 functions setsolver and addsolver have been renamed to setSolver and
  1954 addSolver; added safe_asm_full_simp_tac;
  1955 
  1956 
  1957 *** HOL ***
  1958 
  1959 * a generic induction tactic `induct_tac' which works for all datatypes and
  1960 also for type `nat';
  1961 
  1962 * a generic case distinction tactic `exhaust_tac' which works for all
  1963 datatypes and also for type `nat';
  1964 
  1965 * each datatype comes with a function `size';
  1966 
  1967 * patterns in case expressions allow tuple patterns as arguments to
  1968 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1969 
  1970 * primrec now also works with type nat;
  1971 
  1972 * recdef: a new declaration form, allows general recursive functions to be
  1973 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1974 
  1975 * the constant for negation has been renamed from "not" to "Not" to
  1976 harmonize with FOL, ZF, LK, etc.;
  1977 
  1978 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1979 infinite lists;
  1980 
  1981 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1982 
  1983 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1984 problems in commutative rings, using axiomatic type classes for + and *;
  1985 
  1986 * more examples in HOL/MiniML and HOL/Auth;
  1987 
  1988 * more default rewrite rules for quantifiers, union/intersection;
  1989 
  1990 * a new constant `arbitrary == @x.False';
  1991 
  1992 * HOLCF/IOA replaces old HOL/IOA;
  1993 
  1994 * HOLCF changes: derived all rules and arities
  1995   + axiomatic type classes instead of classes
  1996   + typedef instead of faking type definitions
  1997   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1998   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1999   + eliminated the types void, one, tr
  2000   + use unit lift and bool lift (with translations) instead of one and tr
  2001   + eliminated blift from Lift3.thy (use Def instead of blift)
  2002   all eliminated rules are derived as theorems --> no visible changes ;
  2003 
  2004 
  2005 *** ZF ***
  2006 
  2007 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2008 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2009 as ZF_cs addSIs [equalityI];
  2010 
  2011 
  2012 
  2013 New in Isabelle94-7 (November 96)
  2014 ---------------------------------
  2015 
  2016 * allowing negative levels (as offsets) in prlev and choplev;
  2017 
  2018 * super-linear speedup for large simplifications;
  2019 
  2020 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2021 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2022 FAIL); can suppress it using the command Delsimps (ex_simps @
  2023 all_simps); De Morgan laws are also now included, by default;
  2024 
  2025 * improved printing of ==>  :  ~:
  2026 
  2027 * new object-logic "Sequents" adds linear logic, while replacing LK
  2028 and Modal (thanks to Sara Kalvala);
  2029 
  2030 * HOL/Auth: correctness proofs for authentication protocols;
  2031 
  2032 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2033 examples on HOL/Auth);
  2034 
  2035 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2036 the rewriter and classical reasoner simultaneously;
  2037 
  2038 * function uresult no longer returns theorems in "standard" format;
  2039 regain previous version by: val uresult = standard o uresult;
  2040 
  2041 
  2042 
  2043 New in Isabelle94-6
  2044 -------------------
  2045 
  2046 * oracles -- these establish an interface between Isabelle and trusted
  2047 external reasoners, which may deliver results as theorems;
  2048 
  2049 * proof objects (in particular record all uses of oracles);
  2050 
  2051 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2052 
  2053 * "constdefs" section in theory files;
  2054 
  2055 * "primrec" section (HOL) no longer requires names;
  2056 
  2057 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2058 
  2059 
  2060 
  2061 New in Isabelle94-5
  2062 -------------------
  2063 
  2064 * reduced space requirements;
  2065 
  2066 * automatic HTML generation from theories;
  2067 
  2068 * theory files no longer require "..." (quotes) around most types;
  2069 
  2070 * new examples, including two proofs of the Church-Rosser theorem;
  2071 
  2072 * non-curried (1994) version of HOL is no longer distributed;
  2073 
  2074 
  2075 
  2076 New in Isabelle94-4
  2077 -------------------
  2078 
  2079 * greatly reduced space requirements;
  2080 
  2081 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2082 
  2083 * searchable theorem database (see the section "Retrieving theorems" on
  2084 page 8 of the Reference Manual);
  2085 
  2086 * new examples, including Grabczewski's monumental case study of the
  2087 Axiom of Choice;
  2088 
  2089 * The previous version of HOL renamed to Old_HOL;
  2090 
  2091 * The new version of HOL (previously called CHOL) uses a curried syntax
  2092 for functions.  Application looks like f a b instead of f(a,b);
  2093 
  2094 * Mutually recursive inductive definitions finally work in HOL;
  2095 
  2096 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2097 translates to the operator "split";
  2098 
  2099 
  2100 
  2101 New in Isabelle94-3
  2102 -------------------
  2103 
  2104 * new infix operator, addss, allowing the classical reasoner to
  2105 perform simplification at each step of its search.  Example:
  2106         fast_tac (cs addss ss)
  2107 
  2108 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2109 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2110 look like (a,b) instead of <a,b>;
  2111 
  2112 * PLEASE NOTE: CHOL will eventually replace HOL!
  2113 
  2114 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2115 It translates to the operator "split".  A new theory of integers is available;
  2116 
  2117 * In ZF, integer numerals now denote two's-complement binary integers.
  2118 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2119 
  2120 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2121 of the Axiom of Choice;
  2122 
  2123 
  2124 
  2125 New in Isabelle94-2
  2126 -------------------
  2127 
  2128 * Significantly faster resolution;
  2129 
  2130 * the different sections in a .thy file can now be mixed and repeated
  2131 freely;
  2132 
  2133 * Database of theorems for FOL, HOL and ZF.  New
  2134 commands including qed, qed_goal and bind_thm store theorems in the database.
  2135 
  2136 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2137 a given theory (thms_of), or find out what theory a theorem was proved in
  2138 (theory_of_thm);
  2139 
  2140 * Bugs fixed in the inductive definition and datatype packages;
  2141 
  2142 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2143 and HOL_dup_cs obsolete;
  2144 
  2145 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2146 have been removed;
  2147 
  2148 * Simpler definition of function space in ZF;
  2149 
  2150 * new results about cardinal and ordinal arithmetic in ZF;
  2151 
  2152 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2153 types;
  2154 
  2155 
  2156 $Id$