NEWS
author wenzelm
Sun Jan 13 19:45:17 2002 +0100 (2002-01-13)
changeset 12734 c5f6d8259ecd
parent 12728 4ed8ab7d677d
child 12736 80f10551fb59
permissions -rw-r--r--
HOL-Real/Complex_Numbers;
     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-Real: added Complex_Numbers (by Gertrud Bauer);
   255 
   256 * HOL-Hyperreal is now a logic image;
   257 
   258 
   259 *** HOLCF ***
   260 
   261 * Isar: consts/constdefs supports mixfix syntax for continuous
   262 operations;
   263 
   264 * Isar: domain package adapted to new-style theory format, e.g. see
   265 HOLCF/ex/Dnat.thy;
   266 
   267 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   268 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   269 lift.induct_tac, always use UU instead of Undef;
   270 
   271 * HOLCF/IMP: updated and converted to new-style theory;
   272 
   273 
   274 *** ZF ***
   275 
   276 * Isar: proper integration of logic-specific tools and packages,
   277 including theory commands '(co)inductive', '(co)datatype',
   278 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   279 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   280 
   281 * theory Main no longer includes AC; for the Axiom of Choice, base
   282 your theory on Main_ZFC;
   283 
   284 * the integer library now covers quotients and remainders, with many
   285 laws relating division to addition, multiplication, etc.;
   286 
   287 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   288 typeless version of the formalism;
   289 
   290 * ZF/IMP: updated and converted to new-style theory format;
   291 
   292 * ZF/Induct: new directory for examples of inductive definitions,
   293 including theory Multiset for multiset orderings; converted to
   294 new-style theory format;
   295 
   296 
   297 *** General ***
   298 
   299 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   300 variable proof controls level of detail: 0 = no proofs (only oracle
   301 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   302 also ref manual for further ML interfaces;
   303 
   304 * Pure/axclass: removed obsolete ML interface
   305 goal_subclass/goal_arity;
   306 
   307 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   308 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   309 separate tokens, so expressions involving minus need to be spaced
   310 properly;
   311 
   312 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   313 rather than "infixl" or "infixr";
   314 
   315 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   316 sort constraint specifications in type inference; e.g. "x::_::foo"
   317 ensures that the type of "x" is of sort "foo" (but not necessarily a
   318 type variable);
   319 
   320 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   321 control output of nested => (types); the default behavior is
   322 "type_brackets";
   323 
   324 * Pure/syntax: builtin parse translation for "_constify" turns valued
   325 tokens into AST constants;
   326 
   327 * Pure/syntax: prefer later declarations of translations and print
   328 translation functions; potential INCOMPATIBILITY: need to reverse
   329 multiple declarations for same syntax element constant;
   330 
   331 * Provers/classical: renamed addaltern to addafter, addSaltern to
   332 addSafter;
   333 
   334 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   335 as well;
   336 
   337 * system: tested support for MacOS X; should be able to get Isabelle +
   338 Proof General to work in a plain Terminal after installing Poly/ML
   339 (e.g. from the Isabelle distribution area) and GNU bash alone
   340 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   341 support requires further installations, e.g. from
   342 http://fink.sourceforge.net/);
   343 
   344 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   345 
   346 * system: Proof General keywords specification is now part of the
   347 Isabelle distribution (see etc/isar-keywords.el);
   348 
   349 * system: support for persistent Proof General sessions (refrain from
   350 outdating all loaded theories on startup); user may create writable
   351 logic images like this: ``isabelle -q HOL Test'';
   352 
   353 * system: smart selection of Isabelle process versus Isabelle
   354 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   355 run both "isabelle" and "Isabelle" even if file names are badly
   356 damaged (executable inspects the case of the first letter of its own
   357 name); added separate "isabelle-process" and "isabelle-interface";
   358 
   359 * system: refrain from any attempt at filtering input streams; no
   360 longer support ``8bit'' encoding of old isabelle font, instead proper
   361 iso-latin characters may now be used; the related isatools
   362 "symbolinput" and "nonascii" have disappeared as well;
   363 
   364 * system: removed old "xterm" interface (the print modes "xterm" and
   365 "xterm_color" are still available for direct use in a suitable
   366 terminal);
   367 
   368 
   369 
   370 New in Isabelle99-2 (February 2001)
   371 -----------------------------------
   372 
   373 *** Overview of INCOMPATIBILITIES ***
   374 
   375 * HOL: please note that theories in the Library and elsewhere often use the
   376 new-style (Isar) format; to refer to their theorems in an ML script you must
   377 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   378 
   379 * HOL: inductive package no longer splits induction rule aggressively,
   380 but only as far as specified by the introductions given; the old
   381 format may be recovered via ML function complete_split_rule or attribute
   382 'split_rule (complete)';
   383 
   384 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   385 gfp_Tarski to gfp_unfold;
   386 
   387 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   388 
   389 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   390 relation); infix "^^" has been renamed "``"; infix "``" has been
   391 renamed "`"; "univalent" has been renamed "single_valued";
   392 
   393 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   394 operation;
   395 
   396 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   397 
   398 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   399 
   400 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   401 consequence, it is no longer monotonic wrt. the local goal context
   402 (which is now passed through the inductive cases);
   403 
   404 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   405 \<gg> to \<ggreater>;
   406 
   407 
   408 *** Document preparation ***
   409 
   410 * \isabellestyle{NAME} selects version of Isabelle output (currently
   411 available: are "it" for near math-mode best-style output, "sl" for
   412 slanted text style, and "tt" for plain type-writer; if no
   413 \isabellestyle command is given, output is according to slanted
   414 type-writer);
   415 
   416 * support sub/super scripts (for single symbols only), input syntax is
   417 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   418 
   419 * some more standard symbols; see Appendix A of the system manual for
   420 the complete list of symbols defined in isabellesym.sty;
   421 
   422 * improved isabelle style files; more abstract symbol implementation
   423 (should now use \isamath{...} and \isatext{...} in custom symbol
   424 definitions);
   425 
   426 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   427 state; Note that presentation of goal states does not conform to
   428 actual human-readable proof documents.  Please do not include goal
   429 states into document output unless you really know what you are doing!
   430 
   431 * proper indentation of antiquoted output with proportional LaTeX
   432 fonts;
   433 
   434 * no_document ML operator temporarily disables LaTeX document
   435 generation;
   436 
   437 * isatool unsymbolize tunes sources for plain ASCII communication;
   438 
   439 
   440 *** Isar ***
   441 
   442 * Pure: Isar now suffers initial goal statements to contain unbound
   443 schematic variables (this does not conform to actual readable proof
   444 documents, due to unpredictable outcome and non-compositional proof
   445 checking); users who know what they are doing may use schematic goals
   446 for Prolog-style synthesis of proven results;
   447 
   448 * Pure: assumption method (an implicit finishing) now handles actual
   449 rules as well;
   450 
   451 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   452 initial goal, declare "that" only as Pure intro (only for single
   453 steps); the "that" rule assumption may now be involved in implicit
   454 finishing, thus ".." becomes a feasible for trivial obtains;
   455 
   456 * Pure: default proof step now includes 'intro_classes'; thus trivial
   457 instance proofs may be performed by "..";
   458 
   459 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   460 statements as well;
   461 
   462 * Pure: more robust selection of calculational rules;
   463 
   464 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   465 rule (as well as the assumption rule);
   466 
   467 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   468 lemmas, using the graph browser tool;
   469 
   470 * Pure: predict failure of "show" in interactive mode;
   471 
   472 * Pure: 'thms_containing' now takes actual terms as arguments;
   473 
   474 * HOL: improved method 'induct' --- now handles non-atomic goals
   475 (potential INCOMPATIBILITY); tuned error handling;
   476 
   477 * HOL: cases and induct rules now provide explicit hints about the
   478 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   479 any remaining facts are inserted into the goal verbatim;
   480 
   481 * HOL: local contexts (aka cases) may now contain term bindings as
   482 well; the 'cases' and 'induct' methods new provide a ?case binding for
   483 the result to be shown in each case;
   484 
   485 * HOL: added 'recdef_tc' command;
   486 
   487 * isatool convert assists in eliminating legacy ML scripts;
   488 
   489 
   490 *** HOL ***
   491 
   492 * HOL/Library: a collection of generic theories to be used together
   493 with main HOL; the theory loader path already includes this directory
   494 by default; the following existing theories have been moved here:
   495 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   496 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   497 
   498 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   499 modelling and verification task performed in Isabelle/HOL +
   500 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   501 
   502 * HOL/Algebra: special summation operator SUM no longer exists, it has
   503 been replaced by setsum; infix 'assoc' now has priority 50 (like
   504 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   505 'domain', this makes the theory consistent with mathematical
   506 literature;
   507 
   508 * HOL basics: added overloaded operations "inverse" and "divide"
   509 (infix "/"), syntax for generic "abs" operation, generic summation
   510 operator \<Sum>;
   511 
   512 * HOL/typedef: simplified package, provide more useful rules (see also
   513 HOL/subset.thy);
   514 
   515 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   516 now expressed as a proper nested rule (old-style tactic scripts may
   517 require atomize_strip_tac to cope with non-atomic premises);
   518 
   519 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   520 to "split_conv" (old name still available for compatibility);
   521 
   522 * HOL: improved concrete syntax for strings (e.g. allows translation
   523 rules with string literals);
   524 
   525 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   526  and Fleuriot's mechanization of analysis, including the transcendental
   527  functions for the reals;
   528 
   529 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   530 
   531 
   532 *** CTT ***
   533 
   534 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   535 "lam" is displayed as TWO lambda-symbols
   536 
   537 * CTT: theory Main now available, containing everything (that is, Bool
   538 and Arith);
   539 
   540 
   541 *** General ***
   542 
   543 * Pure: the Simplifier has been implemented properly as a derived rule
   544 outside of the actual kernel (at last!); the overall performance
   545 penalty in practical applications is about 50%, while reliability of
   546 the Isabelle inference kernel has been greatly improved;
   547 
   548 * print modes "brackets" and "no_brackets" control output of nested =>
   549 (types) and ==> (props); the default behaviour is "brackets";
   550 
   551 * Provers: fast_tac (and friends) now handle actual object-logic rules
   552 as assumptions as well;
   553 
   554 * system: support Poly/ML 4.0;
   555 
   556 * system: isatool install handles KDE version 1 or 2;
   557 
   558 
   559 
   560 New in Isabelle99-1 (October 2000)
   561 ----------------------------------
   562 
   563 *** Overview of INCOMPATIBILITIES ***
   564 
   565 * HOL: simplification of natural numbers is much changed; to partly
   566 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   567 issue the following ML commands:
   568 
   569   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   570   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   571 
   572 * HOL: simplification no longer dives into case-expressions; this is
   573 controlled by "t.weak_case_cong" for each datatype t;
   574 
   575 * HOL: nat_less_induct renamed to less_induct;
   576 
   577 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   578 fixsome to patch .thy and .ML sources automatically;
   579 
   580   select_equality  -> some_equality
   581   select_eq_Ex     -> some_eq_ex
   582   selectI2EX       -> someI2_ex
   583   selectI2         -> someI2
   584   selectI          -> someI
   585   select1_equality -> some1_equality
   586   Eps_sym_eq       -> some_sym_eq_trivial
   587   Eps_eq           -> some_eq_trivial
   588 
   589 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   590 
   591 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   592 instead);
   593 
   594 * HOL: the recursion equations generated by 'recdef' are now called
   595 f.simps instead of f.rules;
   596 
   597 * HOL: qed_spec_mp now also handles bounded ALL as well;
   598 
   599 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   600 sometimes be needed;
   601 
   602 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   603 
   604 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   605 
   606 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   607 product is now "<*>" instead of "Times"; the lexicographic product is
   608 now "<*lex*>" instead of "**";
   609 
   610 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   611 of main HOL, but was unused); better use HOL's datatype package;
   612 
   613 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   614 the old syntax may be recovered as follows:
   615 
   616   syntax (symbols)
   617     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   618       (infixl "\\<oplus>" 100)
   619 
   620 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   621 
   622 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   623 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   624 internally;
   625 
   626 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   627 changed from A/r to A//r;
   628 
   629 * ZF: new treatment of arithmetic (nat & int) may break some old
   630 proofs;
   631 
   632 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   633 rulify -> rule_format, elimify -> elim_format, ...);
   634 
   635 * Isar/Provers: intro/elim/dest attributes changed; renamed
   636 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   637 should have to change intro!! to intro? only); replaced "delrule" by
   638 "rule del";
   639 
   640 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   641 
   642 * Provers: strengthened force_tac by using new first_best_tac;
   643 
   644 * LaTeX document preparation: several changes of isabelle.sty (see
   645 lib/texinputs);
   646 
   647 
   648 *** Document preparation ***
   649 
   650 * formal comments (text blocks etc.) in new-style theories may now
   651 contain antiquotations of thm/prop/term/typ/text to be presented
   652 according to latex print mode; concrete syntax is like this:
   653 @{term[show_types] "f(x) = a + x"};
   654 
   655 * isatool mkdir provides easy setup of Isabelle session directories,
   656 including proper document sources;
   657 
   658 * generated LaTeX sources are now deleted after successful run
   659 (isatool document -c); may retain a copy somewhere else via -D option
   660 of isatool usedir;
   661 
   662 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   663 style files, achieving self-contained LaTeX sources and simplifying
   664 LaTeX debugging;
   665 
   666 * old-style theories now produce (crude) LaTeX output as well;
   667 
   668 * browser info session directories are now self-contained (may be put
   669 on WWW server seperately); improved graphs of nested sessions; removed
   670 graph for 'all sessions';
   671 
   672 * several improvements in isabelle style files; \isabellestyle{it}
   673 produces fake math mode output; \isamarkupheader is now \section by
   674 default; see lib/texinputs/isabelle.sty etc.;
   675 
   676 
   677 *** Isar ***
   678 
   679 * Isar/Pure: local results and corresponding term bindings are now
   680 subject to Hindley-Milner polymorphism (similar to ML); this
   681 accommodates incremental type-inference very nicely;
   682 
   683 * Isar/Pure: new derived language element 'obtain' supports
   684 generalized existence reasoning;
   685 
   686 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   687 support accumulation of results, without applying any rules yet;
   688 useful to collect intermediate results without explicit name
   689 references, and for use with transitivity rules with more than 2
   690 premises;
   691 
   692 * Isar/Pure: scalable support for case-analysis type proofs: new
   693 'case' language element refers to local contexts symbolically, as
   694 produced by certain proof methods; internally, case names are attached
   695 to theorems as "tags";
   696 
   697 * Isar/Pure: theory command 'hide' removes declarations from
   698 class/type/const name spaces;
   699 
   700 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   701 indicate potential overloading;
   702 
   703 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   704 
   705 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   706 "{a,b,c}" instead of {a,b,c};
   707 
   708 * Isar/Pure now provides its own version of intro/elim/dest
   709 attributes; useful for building new logics, but beware of confusion
   710 with the version in Provers/classical;
   711 
   712 * Isar/Pure: the local context of (non-atomic) goals is provided via
   713 case name 'antecedent';
   714 
   715 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   716 to the current context is now done automatically);
   717 
   718 * Isar/Pure: theory command 'method_setup' provides a simple interface
   719 for definining proof methods in ML;
   720 
   721 * Isar/Provers: intro/elim/dest attributes changed; renamed
   722 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   723 most cases, one should have to change intro!! to intro? only);
   724 replaced "delrule" by "rule del";
   725 
   726 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   727 'symmetric' attribute (the latter supercedes [RS sym]);
   728 
   729 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   730 method modifier); 'simp' method: 'only:' modifier removes loopers as
   731 well (including splits);
   732 
   733 * Isar/Provers: Simplifier and Classical methods now support all kind
   734 of modifiers used in the past, including 'cong', 'iff', etc.
   735 
   736 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   737 of Simplifier and Classical reasoner);
   738 
   739 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   740 now support named cases; major packages (inductive, datatype, primrec,
   741 recdef) support case names and properly name parameters;
   742 
   743 * Isar/HOL: new transitivity rules for substitution in inequalities --
   744 monotonicity conditions are extracted to be proven at end of
   745 calculations;
   746 
   747 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   748 method anyway;
   749 
   750 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   751 split_if split_if_asm; datatype package provides theorems foo.splits =
   752 foo.split foo.split_asm for each datatype;
   753 
   754 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   755 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   756 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   757 use "(cases (simplified))" method in proper proof texts);
   758 
   759 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   760 
   761 * Isar: names of theorems etc. may be natural numbers as well;
   762 
   763 * Isar: 'pr' command: optional arguments for goals_limit and
   764 ProofContext.prems_limit; no longer prints theory contexts, but only
   765 proof states;
   766 
   767 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   768 additional print modes to be specified; e.g. "pr(latex)" will print
   769 proof state according to the Isabelle LaTeX style;
   770 
   771 * Isar: improved support for emulating tactic scripts, including proof
   772 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   773 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   774 (for HOL datatypes);
   775 
   776 * Isar: simplified (more robust) goal selection of proof methods: 1st
   777 goal, all goals, or explicit goal specifier (tactic emulation); thus
   778 'proof method scripts' have to be in depth-first order;
   779 
   780 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   781 
   782 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   783 should instead use individual commands for printing items
   784 (print_commands, print_methods etc.);
   785 
   786 * Isar: added 'nothing' --- the empty list of theorems;
   787 
   788 
   789 *** HOL ***
   790 
   791 * HOL/MicroJava: formalization of a fragment of Java, together with a
   792 corresponding virtual machine and a specification of its bytecode
   793 verifier and a lightweight bytecode verifier, including proofs of
   794 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   795 Cornelia Pusch (see also the homepage of project Bali at
   796 http://isabelle.in.tum.de/Bali/);
   797 
   798 * HOL/Algebra: new theory of rings and univariate polynomials, by
   799 Clemens Ballarin;
   800 
   801 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   802 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   803 Rasmussen;
   804 
   805 * HOL/Lattice: fundamental concepts of lattice theory and order
   806 structures, including duals, properties of bounds versus algebraic
   807 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   808 Theorem for complete lattices etc.; may also serve as a demonstration
   809 for abstract algebraic reasoning using axiomatic type classes, and
   810 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   811 
   812 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   813 von Oheimb;
   814 
   815 * HOL/IMPP: extension of IMP with local variables and mutually
   816 recursive procedures, by David von Oheimb;
   817 
   818 * HOL/Lambda: converted into new-style theory and document;
   819 
   820 * HOL/ex/Multiquote: example of multiple nested quotations and
   821 anti-quotations -- basically a generalized version of de-Bruijn
   822 representation; very useful in avoiding lifting of operations;
   823 
   824 * HOL/record: added general record equality rule to simpset; fixed
   825 select-update simplification procedure to handle extended records as
   826 well; admit "r" as field name;
   827 
   828 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   829 other numeric types and also as the identity of groups, rings, etc.;
   830 
   831 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   832 Types nat and int belong to this axclass;
   833 
   834 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   835    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   836    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   837   two terms #m*u and #n*u are replaced by #(m+n)*u
   838     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   839   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   840     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   841 
   842 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   843 powerful prover for predicate logic but knows nothing of clasets; see
   844 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   845 
   846 * HOL: new version of "case_tac" subsumes both boolean case split and
   847 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   848 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   849 
   850 * HOL: simplification no longer dives into case-expressions: only the
   851 selector expression is simplified, but not the remaining arms; to
   852 enable full simplification of case-expressions for datatype t, you may
   853 remove t.weak_case_cong from the simpset, either globally (Delcongs
   854 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   855 
   856 * HOL/recdef: the recursion equations generated by 'recdef' for
   857 function 'f' are now called f.simps instead of f.rules; if all
   858 termination conditions are proved automatically, these simplification
   859 rules are added to the simpset, as in primrec; rules may be named
   860 individually as well, resulting in a separate list of theorems for
   861 each equation;
   862 
   863 * HOL/While is a new theory that provides a while-combinator. It
   864 permits the definition of tail-recursive functions without the
   865 provision of a termination measure. The latter is necessary once the
   866 invariant proof rule for while is applied.
   867 
   868 * HOL: new (overloaded) notation for the set of elements below/above
   869 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   870 
   871 * HOL: theorems impI, allI, ballI bound as "strip";
   872 
   873 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   874 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   875 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   876 
   877 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   878 
   879 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   880 main HOL, but was unused);
   881 
   882 * HOL: fewer consts declared as global (e.g. have to refer to
   883 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   884 
   885 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   886 in case of overlap with user translations (e.g. judgements over
   887 tuples); (note that the underlying logical represenation is still
   888 bogus);
   889 
   890 
   891 *** ZF ***
   892 
   893 * ZF: simplification automatically cancels common terms in arithmetic
   894 expressions over nat and int;
   895 
   896 * ZF: new treatment of nat to minimize type-checking: all operators
   897 coerce their operands to a natural number using the function natify,
   898 making the algebraic laws unconditional;
   899 
   900 * ZF: as above, for int: operators coerce their operands to an integer
   901 using the function intify;
   902 
   903 * ZF: the integer library now contains many of the usual laws for the
   904 orderings, including $<=, and monotonicity laws for $+ and $*;
   905 
   906 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   907 simplification;
   908 
   909 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   910 to the simplifier and classical reasoner simultaneously;
   911 
   912 
   913 *** General ***
   914 
   915 * Provers: blast_tac now handles actual object-logic rules as
   916 assumptions; note that auto_tac uses blast_tac internally as well;
   917 
   918 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   919 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   920 
   921 * Provers: delrules now handles destruct rules as well (no longer need
   922 explicit make_elim);
   923 
   924 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   925   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   926 use instead the strong form,
   927   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   928 in HOL, FOL and ZF the function cla_make_elim will create such rules
   929 from destruct-rules;
   930 
   931 * Provers: Simplifier.easy_setup provides a fast path to basic
   932 Simplifier setup for new object-logics;
   933 
   934 * Pure: AST translation rules no longer require constant head on LHS;
   935 
   936 * Pure: improved name spaces: ambiguous output is qualified; support
   937 for hiding of names;
   938 
   939 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   940 XSYMBOL_HOME; no longer need to do manual configuration in most
   941 situations;
   942 
   943 * system: compression of ML heaps images may now be controlled via -c
   944 option of isabelle and isatool usedir (currently only observed by
   945 Poly/ML);
   946 
   947 * system: isatool installfonts may handle X-Symbol fonts as well (very
   948 useful for remote X11);
   949 
   950 * system: provide TAGS file for Isabelle sources;
   951 
   952 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   953 order;
   954 
   955 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   956 timing flag supersedes proof_timing and Toplevel.trace;
   957 
   958 * ML: new combinators |>> and |>>> for incremental transformations
   959 with secondary results (e.g. certain theory extensions):
   960 
   961 * ML: PureThy.add_defs gets additional argument to indicate potential
   962 overloading (usually false);
   963 
   964 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   965 results;
   966 
   967 
   968 
   969 New in Isabelle99 (October 1999)
   970 --------------------------------
   971 
   972 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   973 
   974 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   975 are no longer simplified.  (This allows the simplifier to unfold recursive
   976 functional programs.)  To restore the old behaviour, declare
   977 
   978     Delcongs [if_weak_cong];
   979 
   980 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   981 complement;
   982 
   983 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   984 
   985 * HOL/datatype: mutual_induct_tac no longer exists --
   986   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   987 
   988 * HOL/typedef: fixed type inference for representing set; type
   989 arguments now have to occur explicitly on the rhs as type constraints;
   990 
   991 * ZF: The con_defs part of an inductive definition may no longer refer
   992 to constants declared in the same theory;
   993 
   994 * HOL, ZF: the function mk_cases, generated by the inductive
   995 definition package, has lost an argument.  To simplify its result, it
   996 uses the default simpset instead of a supplied list of theorems.
   997 
   998 * HOL/List: the constructors of type list are now Nil and Cons;
   999 
  1000 * Simplifier: the type of the infix ML functions
  1001         setSSolver addSSolver setSolver addSolver
  1002 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1003 for packaging solvers. A solver is created via
  1004         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1005 where the string argument is only a comment.
  1006 
  1007 
  1008 *** Proof tools ***
  1009 
  1010 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1011 decision procedure for linear arithmetic. Currently it is used for
  1012 types `nat', `int', and `real' in HOL (see below); it can, should and
  1013 will be instantiated for other types and logics as well.
  1014 
  1015 * The simplifier now accepts rewrite rules with flexible heads, eg
  1016      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1017   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1018   matching.
  1019 
  1020 
  1021 *** General ***
  1022 
  1023 * New Isabelle/Isar subsystem provides an alternative to traditional
  1024 tactical theorem proving; together with the ProofGeneral/isar user
  1025 interface it offers an interactive environment for developing human
  1026 readable proof documents (Isar == Intelligible semi-automated
  1027 reasoning); for further information see isatool doc isar-ref,
  1028 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1029 
  1030 * improved and simplified presentation of theories: better HTML markup
  1031 (including colors), graph views in several sizes; isatool usedir now
  1032 provides a proper interface for user theories (via -P option); actual
  1033 document preparation based on (PDF)LaTeX is available as well (for
  1034 new-style theories only); see isatool doc system for more information;
  1035 
  1036 * native support for Proof General, both for classic Isabelle and
  1037 Isabelle/Isar;
  1038 
  1039 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1040 using the graph browser tool;
  1041 
  1042 * Isabelle manuals now also available as PDF;
  1043 
  1044 * theory loader rewritten from scratch (may not be fully
  1045 bug-compatible); old loadpath variable has been replaced by show_path,
  1046 add_path, del_path, reset_path functions; new operations such as
  1047 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1048 isatool doc ref);
  1049 
  1050 * improved isatool install: option -k creates KDE application icon,
  1051 option -p DIR installs standalone binaries;
  1052 
  1053 * added ML_PLATFORM setting (useful for cross-platform installations);
  1054 more robust handling of platform specific ML images for SML/NJ;
  1055 
  1056 * the settings environment is now statically scoped, i.e. it is never
  1057 created again in sub-processes invoked from isabelle, isatool, or
  1058 Isabelle;
  1059 
  1060 * path element specification '~~' refers to '$ISABELLE_HOME';
  1061 
  1062 * in locales, the "assumes" and "defines" parts may be omitted if
  1063 empty;
  1064 
  1065 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1066 long arrows);
  1067 
  1068 * new print_mode "HTML";
  1069 
  1070 * new flag show_tags controls display of tags of theorems (which are
  1071 basically just comments that may be attached by some tools);
  1072 
  1073 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1074 mode and goal output format:
  1075 
  1076 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1077 244c244
  1078 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1079 ---
  1080 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1081 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1082 181c181
  1083 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1084 ---
  1085 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1086 
  1087 * function bind_thms stores lists of theorems (cf. bind_thm);
  1088 
  1089 * new shorthand tactics ftac, eatac, datac, fatac;
  1090 
  1091 * qed (and friends) now accept "" as result name; in that case the
  1092 theorem is not stored, but proper checks and presentation of the
  1093 result still apply;
  1094 
  1095 * theorem database now also indexes constants "Trueprop", "all",
  1096 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1097 
  1098 
  1099 *** HOL ***
  1100 
  1101 ** HOL arithmetic **
  1102 
  1103 * There are now decision procedures for linear arithmetic over nat and
  1104 int:
  1105 
  1106 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1107 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1108 are treated as atomic; subformulae not involving type `nat' or `int'
  1109 are ignored; quantified subformulae are ignored unless they are
  1110 positive universal or negative existential. The tactic has to be
  1111 invoked by hand and can be a little bit slow. In particular, the
  1112 running time is exponential in the number of occurrences of `min' and
  1113 `max', and `-' on `nat'.
  1114 
  1115 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1116 (negated) (in)equalities among the premises and the conclusion into
  1117 account (i.e. no compound formulae) and does not know about `min' and
  1118 `max', and `-' on `nat'. It is fast and is used automatically by the
  1119 simplifier.
  1120 
  1121 NB: At the moment, these decision procedures do not cope with mixed
  1122 nat/int formulae where the two parts interact, such as `m < n ==>
  1123 int(m) < int(n)'.
  1124 
  1125 * HOL/Numeral provides a generic theory of numerals (encoded
  1126 efficiently as bit strings); setup for types nat/int/real is in place;
  1127 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1128 int, existing theories and proof scripts may require a few additional
  1129 type constraints;
  1130 
  1131 * integer division and remainder can now be performed on constant
  1132 arguments;
  1133 
  1134 * many properties of integer multiplication, division and remainder
  1135 are now available;
  1136 
  1137 * An interface to the Stanford Validity Checker (SVC) is available through the
  1138 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1139 are proved automatically.  SVC must be installed separately, and its results
  1140 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1141 invocation of the underlying oracle).  For SVC see
  1142   http://verify.stanford.edu/SVC
  1143 
  1144 * IsaMakefile: the HOL-Real target now builds an actual image;
  1145 
  1146 
  1147 ** HOL misc **
  1148 
  1149 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1150 (in Isabelle/Isar) -- by Gertrud Bauer;
  1151 
  1152 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1153 analysis for assembly languages with subtypes;
  1154 
  1155 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1156 -- avoids syntactic ambiguities and treats state, transition, and
  1157 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1158 changed syntax and (many) tactics;
  1159 
  1160 * HOL/inductive: Now also handles more general introduction rules such
  1161   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1162   theorems are now maintained within the theory (maintained via the
  1163   "mono" attribute);
  1164 
  1165 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1166   (using function types) such as
  1167 
  1168   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1169 
  1170 * HOL/record: record_simproc (part of the default simpset) takes care
  1171 of selectors applied to updated records; record_split_tac is no longer
  1172 part of the default claset; update_defs may now be removed from the
  1173 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1174 
  1175   claset_ref () := claset() addSWrapper record_split_wrapper;
  1176   Delsimprocs [record_simproc]
  1177 
  1178 * HOL/typedef: fixed type inference for representing set; type
  1179 arguments now have to occur explicitly on the rhs as type constraints;
  1180 
  1181 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1182 names rather than an ML expression;
  1183 
  1184 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1185 supplied later.  Program schemes can be defined, such as
  1186     "While B C s = (if B s then While B C (C s) else s)"
  1187 where the well-founded relation can be chosen after B and C have been given.
  1188 
  1189 * HOL/List: the constructors of type list are now Nil and Cons;
  1190 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1191 course, ML tools referring to List.list.op # etc. have to be adapted;
  1192 
  1193 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1194 disabled by default; run isabelle with option -m HOL to get back to
  1195 the original Gordon/HOL-style output;
  1196 
  1197 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1198 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1199 
  1200 * HOL basic syntax simplified (more orthogonal): all variants of
  1201 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1202 Eps operator is provided as well: "SOME x. P[x]";
  1203 
  1204 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1205 
  1206 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1207 thus available for user theories;
  1208 
  1209 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1210 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1211 time;
  1212 
  1213 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1214 several times and then mp;
  1215 
  1216 
  1217 *** LK ***
  1218 
  1219 * the notation <<...>> is now available as a notation for sequences of
  1220 formulas;
  1221 
  1222 * the simplifier is now installed
  1223 
  1224 * the axiom system has been generalized (thanks to Soren Heilmann)
  1225 
  1226 * the classical reasoner now has a default rule database
  1227 
  1228 
  1229 *** ZF ***
  1230 
  1231 * new primrec section allows primitive recursive functions to be given
  1232 directly (as in HOL) over datatypes and the natural numbers;
  1233 
  1234 * new tactics induct_tac and exhaust_tac for induction (or case
  1235 analysis) over datatypes and the natural numbers;
  1236 
  1237 * the datatype declaration of type T now defines the recursor T_rec;
  1238 
  1239 * simplification automatically does freeness reasoning for datatype
  1240 constructors;
  1241 
  1242 * automatic type-inference, with AddTCs command to insert new
  1243 type-checking rules;
  1244 
  1245 * datatype introduction rules are now added as Safe Introduction rules
  1246 to the claset;
  1247 
  1248 * the syntax "if P then x else y" is now available in addition to
  1249 if(P,x,y);
  1250 
  1251 
  1252 *** Internal programming interfaces ***
  1253 
  1254 * tuned simplifier trace output; new flag debug_simp;
  1255 
  1256 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1257 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1258 
  1259 * AxClass.axclass_tac lost the theory argument;
  1260 
  1261 * tuned current_goals_markers semantics: begin / end goal avoids
  1262 printing empty lines;
  1263 
  1264 * removed prs and prs_fn hook, which was broken because it did not
  1265 include \n in its semantics, forcing writeln to add one
  1266 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1267 string -> unit if you really want to output text without newline;
  1268 
  1269 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1270 plain output, interface builders may have to enable 'isabelle_font'
  1271 mode to get Isabelle font glyphs as before;
  1272 
  1273 * refined token_translation interface; INCOMPATIBILITY: output length
  1274 now of type real instead of int;
  1275 
  1276 * theory loader actions may be traced via new ThyInfo.add_hook
  1277 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1278 your own database of information attached to *whole* theories -- as
  1279 opposed to intra-theory data slots offered via TheoryDataFun;
  1280 
  1281 * proper handling of dangling sort hypotheses (at last!);
  1282 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1283 extra sort hypotheses that can be witnessed from the type signature;
  1284 the force_strip_shyps flag is gone, any remaining shyps are simply
  1285 left in the theorem (with a warning issued by strip_shyps_warning);
  1286 
  1287 
  1288 
  1289 New in Isabelle98-1 (October 1998)
  1290 ----------------------------------
  1291 
  1292 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1293 
  1294 * several changes of automated proof tools;
  1295 
  1296 * HOL: major changes to the inductive and datatype packages, including
  1297 some minor incompatibilities of theory syntax;
  1298 
  1299 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1300 called `inj_on';
  1301 
  1302 * HOL: removed duplicate thms in Arith:
  1303   less_imp_add_less  should be replaced by  trans_less_add1
  1304   le_imp_add_le      should be replaced by  trans_le_add1
  1305 
  1306 * HOL: unary minus is now overloaded (new type constraints may be
  1307 required);
  1308 
  1309 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1310 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1311 now taken as an integer constant.
  1312 
  1313 * Pure: ML function 'theory_of' renamed to 'theory';
  1314 
  1315 
  1316 *** Proof tools ***
  1317 
  1318 * Simplifier:
  1319   1. Asm_full_simp_tac is now more aggressive.
  1320      1. It will sometimes reorient premises if that increases their power to
  1321         simplify.
  1322      2. It does no longer proceed strictly from left to right but may also
  1323         rotate premises to achieve further simplification.
  1324      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1325      old Asm_full_simp_tac in that it does not rotate premises.
  1326   2. The simplifier now knows a little bit about nat-arithmetic.
  1327 
  1328 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1329 allows for selected deletion of wrappers, by introduction of names for
  1330 wrapper functionals.  This implies that addbefore, addSbefore,
  1331 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1332 and that adding two tactics with the same name overwrites the first
  1333 one (emitting a warning).
  1334   type wrapper = (int -> tactic) -> (int -> tactic)
  1335   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1336   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1337   delWrapper, delSWrapper: claset *  string            -> claset
  1338   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1339 
  1340 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1341 semantics; addbefore now affects only the unsafe part of step_tac
  1342 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1343 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1344 by Force_tac;
  1345 
  1346 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1347 compWrapper; added safe wrapper (and access functions for it);
  1348 
  1349 * HOL/split_all_tac is now much faster and fails if there is nothing
  1350 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1351 and the names of the automatically generated variables have changed.
  1352 split_all_tac has moved within claset() from unsafe wrappers to safe
  1353 wrappers, which means that !!-bound variables are split much more
  1354 aggressively, and safe_tac and clarify_tac now split such variables.
  1355 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1356 Note: the same holds for record_split_tac, which does the job of
  1357 split_all_tac for record fields.
  1358 
  1359 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1360 permanently to the default simpset using Addsplits just like
  1361 Addsimps. They can be removed via Delsplits just like
  1362 Delsimps. Lower-case versions are also available.
  1363 
  1364 * HOL/Simplifier: The rule split_if is now part of the default
  1365 simpset. This means that the simplifier will eliminate all occurrences
  1366 of if-then-else in the conclusion of a goal. To prevent this, you can
  1367 either remove split_if completely from the default simpset by
  1368 `Delsplits [split_if]' or remove it in a specific call of the
  1369 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1370 other case splitting rules to/from the default simpset: every datatype
  1371 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1372 t is the name of the datatype).
  1373 
  1374 * Classical reasoner / Simplifier combination: new force_tac (and
  1375 derivatives Force_tac, force) combines rewriting and classical
  1376 reasoning (and whatever other tools) similarly to auto_tac, but is
  1377 aimed to solve the given subgoal completely.
  1378 
  1379 
  1380 *** General ***
  1381 
  1382 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1383 and `goalw': the theory is no longer needed as an explicit argument -
  1384 the current theory context is used; assumptions are no longer returned
  1385 at the ML-level unless one of them starts with ==> or !!; it is
  1386 recommended to convert to these new commands using isatool fixgoal
  1387 (backup your sources first!);
  1388 
  1389 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1390 the current theory context, and 'theory' to lookup stored theories;
  1391 
  1392 * new theory section 'locale' for declaring constants, assumptions and
  1393 definitions that have local scope;
  1394 
  1395 * new theory section 'nonterminals' for purely syntactic types;
  1396 
  1397 * new theory section 'setup' for generic ML setup functions
  1398 (e.g. package initialization);
  1399 
  1400 * the distribution now includes Isabelle icons: see
  1401 lib/logo/isabelle-{small,tiny}.xpm;
  1402 
  1403 * isatool install - install binaries with absolute references to
  1404 ISABELLE_HOME/bin;
  1405 
  1406 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1407 
  1408 * print mode 'emacs' reserved for Isamode;
  1409 
  1410 * support multiple print (ast) translations per constant name;
  1411 
  1412 * theorems involving oracles are now printed with a suffixed [!];
  1413 
  1414 
  1415 *** HOL ***
  1416 
  1417 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1418 
  1419 * HOL/inductive package reorganized and improved: now supports mutual
  1420 definitions such as
  1421 
  1422   inductive EVEN ODD
  1423     intrs
  1424       null "0 : EVEN"
  1425       oddI "n : EVEN ==> Suc n : ODD"
  1426       evenI "n : ODD ==> Suc n : EVEN"
  1427 
  1428 new theorem list "elims" contains an elimination rule for each of the
  1429 recursive sets; inductive definitions now handle disjunctive premises
  1430 correctly (also ZF);
  1431 
  1432 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1433 "mutual_induct" no longer exists - the induction rule is always
  1434 contained in "induct";
  1435 
  1436 
  1437 * HOL/datatype package re-implemented and greatly improved: now
  1438 supports mutually recursive datatypes such as
  1439 
  1440   datatype
  1441     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1442             | SUM ('a aexp) ('a aexp)
  1443             | DIFF ('a aexp) ('a aexp)
  1444             | NUM 'a
  1445   and
  1446     'a bexp = LESS ('a aexp) ('a aexp)
  1447             | AND ('a bexp) ('a bexp)
  1448             | OR ('a bexp) ('a bexp)
  1449 
  1450 as well as indirectly recursive datatypes such as
  1451 
  1452   datatype
  1453     ('a, 'b) term = Var 'a
  1454                   | App 'b ((('a, 'b) term) list)
  1455 
  1456 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1457 induction on mutually / indirectly recursive datatypes.
  1458 
  1459 Primrec equations are now stored in theory and can be accessed via
  1460 <function_name>.simps.
  1461 
  1462 INCOMPATIBILITIES:
  1463 
  1464   - Theories using datatypes must now have theory Datatype as an
  1465     ancestor.
  1466   - The specific <typename>.induct_tac no longer exists - use the
  1467     generic induct_tac instead.
  1468   - natE has been renamed to nat.exhaust - use exhaust_tac
  1469     instead of res_inst_tac ... natE. Note that the variable
  1470     names in nat.exhaust differ from the names in natE, this
  1471     may cause some "fragile" proofs to fail.
  1472   - The theorems split_<typename>_case and split_<typename>_case_asm
  1473     have been renamed to <typename>.split and <typename>.split_asm.
  1474   - Since default sorts of type variables are now handled correctly,
  1475     some datatype definitions may have to be annotated with explicit
  1476     sort constraints.
  1477   - Primrec definitions no longer require function name and type
  1478     of recursive argument.
  1479 
  1480 Consider using isatool fixdatatype to adapt your theories and proof
  1481 scripts to the new package (backup your sources first!).
  1482 
  1483 
  1484 * HOL/record package: considerably improved implementation; now
  1485 includes concrete syntax for record types, terms, updates; theorems
  1486 for surjective pairing and splitting !!-bound record variables; proof
  1487 support is as follows:
  1488 
  1489   1) standard conversions (selectors or updates applied to record
  1490 constructor terms) are part of the standard simpset;
  1491 
  1492   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1493 made part of standard simpset and claset via addIffs;
  1494 
  1495   3) a tactic for record field splitting (record_split_tac) is part of
  1496 the standard claset (addSWrapper);
  1497 
  1498 To get a better idea about these rules you may retrieve them via
  1499 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1500 the name of your record type.
  1501 
  1502 The split tactic 3) conceptually simplifies by the following rule:
  1503 
  1504   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1505 
  1506 Thus any record variable that is bound by meta-all will automatically
  1507 blow up into some record constructor term, consequently the
  1508 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1509 solve record problems automatically.
  1510 
  1511 
  1512 * reorganized the main HOL image: HOL/Integ and String loaded by
  1513 default; theory Main includes everything;
  1514 
  1515 * automatic simplification of integer sums and comparisons, using cancellation;
  1516 
  1517 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1518 
  1519 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1520 
  1521 * many new identities for unions, intersections, set difference, etc.;
  1522 
  1523 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1524 called split_if, split_split, split_sum_case and split_nat_case (to go
  1525 with add/delsplits);
  1526 
  1527 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1528 (?x::unit) = (); this is made part of the default simpset, which COULD
  1529 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1530 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1531 unit_abs_eta_conv is added in order to counter the effect of
  1532 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1533 %u.f();
  1534 
  1535 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1536 makes more sense);
  1537 
  1538 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1539   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1540   disjointness reasoning but breaking a few old proofs.
  1541 
  1542 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1543 to 'converse' from 'inverse' (for compatibility with ZF and some
  1544 literature);
  1545 
  1546 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1547 the well-founded relation;
  1548 
  1549 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1550     Compl A.  The "Compl" syntax remains available as input syntax for this
  1551     release ONLY.
  1552 
  1553 * HOL/Update: new theory of function updates:
  1554     f(a:=b) == %x. if x=a then b else f x
  1555 may also be iterated as in f(a:=b,c:=d,...);
  1556 
  1557 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1558 
  1559 * HOL/List:
  1560   - new function list_update written xs[i:=v] that updates the i-th
  1561     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1562   - new function `upt' written [i..j(] which generates the list
  1563     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1564     bound write [i..j], which is a shorthand for [i..j+1(].
  1565   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1566 
  1567 * HOL/Arith:
  1568   - removed 'pred' (predecessor) function;
  1569   - generalized some theorems about n-1;
  1570   - many new laws about "div" and "mod";
  1571   - new laws about greatest common divisors (see theory ex/Primes);
  1572 
  1573 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1574 instead of "inverse";
  1575 
  1576 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1577   of the multiset ordering;
  1578 
  1579 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1580   (not included by default);
  1581 
  1582 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1583 
  1584 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1585   programs, i.e. different program variables may have different types.
  1586 
  1587 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1588   [previously, this check worked only if the rewrite rule was unconditional]
  1589   Now rew can involve either definitions or equalities (either == or =).
  1590 
  1591 
  1592 *** ZF ***
  1593 
  1594 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1595   only the theorems proved on ZF.ML;
  1596 
  1597 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1598   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1599   disjointness reasoning but breaking a few old proofs.
  1600 
  1601 * ZF/Update: new theory of function updates
  1602     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1603   may also be iterated as in f(a:=b,c:=d,...);
  1604 
  1605 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1606 
  1607 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1608   [previously, this check worked only if the rewrite rule was unconditional]
  1609   Now rew can involve either definitions or equalities (either == or =).
  1610 
  1611 * case_tac provided for compatibility with HOL
  1612     (like the old excluded_middle_tac, but with subgoals swapped)
  1613 
  1614 
  1615 *** Internal programming interfaces ***
  1616 
  1617 * Pure: several new basic modules made available for general use, see
  1618 also src/Pure/README;
  1619 
  1620 * improved the theory data mechanism to support encapsulation (data
  1621 kind name replaced by private Object.kind, acting as authorization
  1622 key); new type-safe user interface via functor TheoryDataFun; generic
  1623 print_data function becomes basically useless;
  1624 
  1625 * removed global_names compatibility flag -- all theory declarations
  1626 are qualified by default;
  1627 
  1628 * module Pure/Syntax now offers quote / antiquote translation
  1629 functions (useful for Hoare logic etc. with implicit dependencies);
  1630 see HOL/ex/Antiquote for an example use;
  1631 
  1632 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1633 cterm -> thm;
  1634 
  1635 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1636 subgoal;
  1637 
  1638 * Display.print_goals function moved to Locale.print_goals;
  1639 
  1640 * standard print function for goals supports current_goals_markers
  1641 variable for marking begin of proof, end of proof, start of goal; the
  1642 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1643 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1644 for example;
  1645 
  1646 
  1647 
  1648 New in Isabelle98 (January 1998)
  1649 --------------------------------
  1650 
  1651 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1652 
  1653 * changed lexical syntax of terms / types: dots made part of long
  1654 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1655 
  1656 * simpset (and claset) reference variable replaced by functions
  1657 simpset / simpset_ref;
  1658 
  1659 * no longer supports theory aliases (via merge) and non-trivial
  1660 implicit merge of thms' signatures;
  1661 
  1662 * most internal names of constants changed due to qualified names;
  1663 
  1664 * changed Pure/Sequence interface (see Pure/seq.ML);
  1665 
  1666 
  1667 *** General Changes ***
  1668 
  1669 * hierachically structured name spaces (for consts, types, axms, thms
  1670 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1671 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1672 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1673 long_names for fully qualified output names; NOTE: ML programs
  1674 (special tactics, packages etc.) referring to internal names may have
  1675 to be adapted to cope with fully qualified names; in case of severe
  1676 backward campatibility problems try setting 'global_names' at compile
  1677 time to have enrything declared within a flat name space; one may also
  1678 fine tune name declarations in theories via the 'global' and 'local'
  1679 section;
  1680 
  1681 * reimplemented the implicit simpset and claset using the new anytype
  1682 data filed in signatures; references simpset:simpset ref etc. are
  1683 replaced by functions simpset:unit->simpset and
  1684 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1685 to patch your ML files accordingly;
  1686 
  1687 * HTML output now includes theory graph data for display with Java
  1688 applet or isatool browser; data generated automatically via isatool
  1689 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1690 
  1691 * defs may now be conditional; improved rewrite_goals_tac to handle
  1692 conditional equations;
  1693 
  1694 * defs now admits additional type arguments, using TYPE('a) syntax;
  1695 
  1696 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1697 creates a new theory node; implicit merge of thms' signatures is
  1698 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1699 transfer:theory->thm->thm in (rare) cases;
  1700 
  1701 * improved handling of draft signatures / theories; draft thms (and
  1702 ctyps, cterms) are automatically promoted to real ones;
  1703 
  1704 * slightly changed interfaces for oracles: admit many per theory, named
  1705 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1706 
  1707 * print_goals: optional output of const types (set show_consts and
  1708 show_types);
  1709 
  1710 * improved output of warnings (###) and errors (***);
  1711 
  1712 * subgoal_tac displays a warning if the new subgoal has type variables;
  1713 
  1714 * removed old README and Makefiles;
  1715 
  1716 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1717 
  1718 * removed obsolete init_pps and init_database;
  1719 
  1720 * deleted the obsolete tactical STATE, which was declared by
  1721     fun STATE tacfun st = tacfun st st;
  1722 
  1723 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1724 (which abbreviates $HOME);
  1725 
  1726 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1727 use isatool fixseq to adapt your ML programs (this works for fully
  1728 qualified references to the Sequence structure only!);
  1729 
  1730 * use_thy no longer requires writable current directory; it always
  1731 reloads .ML *and* .thy file, if either one is out of date;
  1732 
  1733 
  1734 *** Classical Reasoner ***
  1735 
  1736 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1737 tactics that use classical reasoning to simplify a subgoal without
  1738 splitting it into several subgoals;
  1739 
  1740 * Safe_tac: like safe_tac but uses the default claset;
  1741 
  1742 
  1743 *** Simplifier ***
  1744 
  1745 * added simplification meta rules:
  1746     (asm_)(full_)simplify: simpset -> thm -> thm;
  1747 
  1748 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1749 logics (again);
  1750 
  1751 * added prems argument to simplification procedures;
  1752 
  1753 * HOL, FOL, ZF: added infix function `addsplits':
  1754   instead of `<simpset> setloop (split_tac <thms>)'
  1755   you can simply write `<simpset> addsplits <thms>'
  1756 
  1757 
  1758 *** Syntax ***
  1759 
  1760 * TYPE('a) syntax for type reflection terms;
  1761 
  1762 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1763 
  1764 * pretty printer: changed order of mixfix annotation preference (again!);
  1765 
  1766 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1767 
  1768 
  1769 *** HOL ***
  1770 
  1771 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1772   with `addloop' of the simplifier to faciliate case splitting in premises.
  1773 
  1774 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1775 
  1776 * HOL/Auth: new protocol proofs including some for the Internet
  1777   protocol TLS;
  1778 
  1779 * HOL/Map: new theory of `maps' a la VDM;
  1780 
  1781 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1782 cancelling out common nat summands from =, <, <= (in)equalities, or
  1783 differences; simplification procedures nat_cancel_factor for
  1784 cancelling common factor from =, <, <= (in)equalities over natural
  1785 sums; nat_cancel contains both kinds of procedures, it is installed by
  1786 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1787 
  1788 * HOL/simplifier: terms of the form
  1789   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1790   are rewritten to
  1791   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1792   and those of the form
  1793   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1794   are rewritten to
  1795   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1796 
  1797 * HOL/datatype
  1798   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1799 
  1800   P(t_case f1 ... fn x) =
  1801      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1802         ...
  1803        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1804      )
  1805 
  1806   and a theorem `split_t_case_asm' of the form
  1807 
  1808   P(t_case f1 ... fn x) =
  1809     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1810         ...
  1811        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1812      )
  1813   which can be added to a simpset via `addsplits'. The existing theorems
  1814   expand_list_case and expand_option_case have been renamed to
  1815   split_list_case and split_option_case.
  1816 
  1817 * HOL/Arithmetic:
  1818   - `pred n' is automatically converted to `n-1'.
  1819     Users are strongly encouraged not to use `pred' any longer,
  1820     because it will disappear altogether at some point.
  1821   - Users are strongly encouraged to write "0 < n" rather than
  1822     "n ~= 0". Theorems and proof tools have been modified towards this
  1823     `standard'.
  1824 
  1825 * HOL/Lists:
  1826   the function "set_of_list" has been renamed "set" (and its theorems too);
  1827   the function "nth" now takes its arguments in the reverse order and
  1828   has acquired the infix notation "!" as in "xs!n".
  1829 
  1830 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1831 
  1832 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1833   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1834 
  1835 * HOL/record: extensible records with schematic structural subtyping
  1836 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1837 still lacks various theorems and concrete record syntax;
  1838 
  1839 
  1840 *** HOLCF ***
  1841 
  1842 * removed "axioms" and "generated by" sections;
  1843 
  1844 * replaced "ops" section by extended "consts" section, which is capable of
  1845   handling the continuous function space "->" directly;
  1846 
  1847 * domain package:
  1848   . proves theorems immediately and stores them in the theory,
  1849   . creates hierachical name space,
  1850   . now uses normal mixfix annotations (instead of cinfix...),
  1851   . minor changes to some names and values (for consistency),
  1852   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1853   . separator between mutual domain defs: changed "," to "and",
  1854   . improved handling of sort constraints;  now they have to
  1855     appear on the left-hand side of the equations only;
  1856 
  1857 * fixed LAM <x,y,zs>.b syntax;
  1858 
  1859 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1860 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1861 
  1862 
  1863 *** FOL and ZF ***
  1864 
  1865 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1866   with `addloop' of the simplifier to faciliate case splitting in premises.
  1867 
  1868 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1869 in HOL, they strip ALL and --> from proved theorems;
  1870 
  1871 
  1872 
  1873 New in Isabelle94-8 (May 1997)
  1874 ------------------------------
  1875 
  1876 *** General Changes ***
  1877 
  1878 * new utilities to build / run / maintain Isabelle etc. (in parts
  1879 still somewhat experimental); old Makefiles etc. still functional;
  1880 
  1881 * new 'Isabelle System Manual';
  1882 
  1883 * INSTALL text, together with ./configure and ./build scripts;
  1884 
  1885 * reimplemented type inference for greater efficiency, better error
  1886 messages and clean internal interface;
  1887 
  1888 * prlim command for dealing with lots of subgoals (an easier way of
  1889 setting goals_limit);
  1890 
  1891 
  1892 *** Syntax ***
  1893 
  1894 * supports alternative (named) syntax tables (parser and pretty
  1895 printer); internal interface is provided by add_modesyntax(_i);
  1896 
  1897 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1898 be used in conjunction with the Isabelle symbol font; uses the
  1899 "symbols" syntax table;
  1900 
  1901 * added token_translation interface (may translate name tokens in
  1902 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1903 the current print_mode); IMPORTANT: user print translation functions
  1904 are responsible for marking newly introduced bounds
  1905 (Syntax.mark_boundT);
  1906 
  1907 * token translations for modes "xterm" and "xterm_color" that display
  1908 names in bold, underline etc. or colors (which requires a color
  1909 version of xterm);
  1910 
  1911 * infixes may now be declared with names independent of their syntax;
  1912 
  1913 * added typed_print_translation (like print_translation, but may
  1914 access type of constant);
  1915 
  1916 
  1917 *** Classical Reasoner ***
  1918 
  1919 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1920 some limitations.  Blast_tac...
  1921   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1922   + ignores elimination rules that don't have the correct format
  1923         (the conclusion MUST be a formula variable)
  1924   + ignores types, which can make HOL proofs fail
  1925   + rules must not require higher-order unification, e.g. apply_type in ZF
  1926     [message "Function Var's argument not a bound variable" relates to this]
  1927   + its proof strategy is more general but can actually be slower
  1928 
  1929 * substitution with equality assumptions no longer permutes other
  1930 assumptions;
  1931 
  1932 * minor changes in semantics of addafter (now called addaltern); renamed
  1933 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1934 (and access functions for it);
  1935 
  1936 * improved combination of classical reasoner and simplifier:
  1937   + functions for handling clasimpsets
  1938   + improvement of addss: now the simplifier is called _after_ the
  1939     safe steps.
  1940   + safe variant of addss called addSss: uses safe simplifications
  1941     _during_ the safe steps. It is more complete as it allows multiple
  1942     instantiations of unknowns (e.g. with slow_tac).
  1943 
  1944 *** Simplifier ***
  1945 
  1946 * added interface for simplification procedures (functions that
  1947 produce *proven* rewrite rules on the fly, depending on current
  1948 redex);
  1949 
  1950 * ordering on terms as parameter (used for ordered rewriting);
  1951 
  1952 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1953 
  1954 * the solver is now split into a safe and an unsafe part.
  1955 This should be invisible for the normal user, except that the
  1956 functions setsolver and addsolver have been renamed to setSolver and
  1957 addSolver; added safe_asm_full_simp_tac;
  1958 
  1959 
  1960 *** HOL ***
  1961 
  1962 * a generic induction tactic `induct_tac' which works for all datatypes and
  1963 also for type `nat';
  1964 
  1965 * a generic case distinction tactic `exhaust_tac' which works for all
  1966 datatypes and also for type `nat';
  1967 
  1968 * each datatype comes with a function `size';
  1969 
  1970 * patterns in case expressions allow tuple patterns as arguments to
  1971 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1972 
  1973 * primrec now also works with type nat;
  1974 
  1975 * recdef: a new declaration form, allows general recursive functions to be
  1976 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1977 
  1978 * the constant for negation has been renamed from "not" to "Not" to
  1979 harmonize with FOL, ZF, LK, etc.;
  1980 
  1981 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1982 infinite lists;
  1983 
  1984 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1985 
  1986 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1987 problems in commutative rings, using axiomatic type classes for + and *;
  1988 
  1989 * more examples in HOL/MiniML and HOL/Auth;
  1990 
  1991 * more default rewrite rules for quantifiers, union/intersection;
  1992 
  1993 * a new constant `arbitrary == @x.False';
  1994 
  1995 * HOLCF/IOA replaces old HOL/IOA;
  1996 
  1997 * HOLCF changes: derived all rules and arities
  1998   + axiomatic type classes instead of classes
  1999   + typedef instead of faking type definitions
  2000   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2001   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2002   + eliminated the types void, one, tr
  2003   + use unit lift and bool lift (with translations) instead of one and tr
  2004   + eliminated blift from Lift3.thy (use Def instead of blift)
  2005   all eliminated rules are derived as theorems --> no visible changes ;
  2006 
  2007 
  2008 *** ZF ***
  2009 
  2010 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2011 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2012 as ZF_cs addSIs [equalityI];
  2013 
  2014 
  2015 
  2016 New in Isabelle94-7 (November 96)
  2017 ---------------------------------
  2018 
  2019 * allowing negative levels (as offsets) in prlev and choplev;
  2020 
  2021 * super-linear speedup for large simplifications;
  2022 
  2023 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2024 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2025 FAIL); can suppress it using the command Delsimps (ex_simps @
  2026 all_simps); De Morgan laws are also now included, by default;
  2027 
  2028 * improved printing of ==>  :  ~:
  2029 
  2030 * new object-logic "Sequents" adds linear logic, while replacing LK
  2031 and Modal (thanks to Sara Kalvala);
  2032 
  2033 * HOL/Auth: correctness proofs for authentication protocols;
  2034 
  2035 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2036 examples on HOL/Auth);
  2037 
  2038 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2039 the rewriter and classical reasoner simultaneously;
  2040 
  2041 * function uresult no longer returns theorems in "standard" format;
  2042 regain previous version by: val uresult = standard o uresult;
  2043 
  2044 
  2045 
  2046 New in Isabelle94-6
  2047 -------------------
  2048 
  2049 * oracles -- these establish an interface between Isabelle and trusted
  2050 external reasoners, which may deliver results as theorems;
  2051 
  2052 * proof objects (in particular record all uses of oracles);
  2053 
  2054 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2055 
  2056 * "constdefs" section in theory files;
  2057 
  2058 * "primrec" section (HOL) no longer requires names;
  2059 
  2060 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2061 
  2062 
  2063 
  2064 New in Isabelle94-5
  2065 -------------------
  2066 
  2067 * reduced space requirements;
  2068 
  2069 * automatic HTML generation from theories;
  2070 
  2071 * theory files no longer require "..." (quotes) around most types;
  2072 
  2073 * new examples, including two proofs of the Church-Rosser theorem;
  2074 
  2075 * non-curried (1994) version of HOL is no longer distributed;
  2076 
  2077 
  2078 
  2079 New in Isabelle94-4
  2080 -------------------
  2081 
  2082 * greatly reduced space requirements;
  2083 
  2084 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2085 
  2086 * searchable theorem database (see the section "Retrieving theorems" on
  2087 page 8 of the Reference Manual);
  2088 
  2089 * new examples, including Grabczewski's monumental case study of the
  2090 Axiom of Choice;
  2091 
  2092 * The previous version of HOL renamed to Old_HOL;
  2093 
  2094 * The new version of HOL (previously called CHOL) uses a curried syntax
  2095 for functions.  Application looks like f a b instead of f(a,b);
  2096 
  2097 * Mutually recursive inductive definitions finally work in HOL;
  2098 
  2099 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2100 translates to the operator "split";
  2101 
  2102 
  2103 
  2104 New in Isabelle94-3
  2105 -------------------
  2106 
  2107 * new infix operator, addss, allowing the classical reasoner to
  2108 perform simplification at each step of its search.  Example:
  2109         fast_tac (cs addss ss)
  2110 
  2111 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2112 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2113 look like (a,b) instead of <a,b>;
  2114 
  2115 * PLEASE NOTE: CHOL will eventually replace HOL!
  2116 
  2117 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2118 It translates to the operator "split".  A new theory of integers is available;
  2119 
  2120 * In ZF, integer numerals now denote two's-complement binary integers.
  2121 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2122 
  2123 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2124 of the Axiom of Choice;
  2125 
  2126 
  2127 
  2128 New in Isabelle94-2
  2129 -------------------
  2130 
  2131 * Significantly faster resolution;
  2132 
  2133 * the different sections in a .thy file can now be mixed and repeated
  2134 freely;
  2135 
  2136 * Database of theorems for FOL, HOL and ZF.  New
  2137 commands including qed, qed_goal and bind_thm store theorems in the database.
  2138 
  2139 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2140 a given theory (thms_of), or find out what theory a theorem was proved in
  2141 (theory_of_thm);
  2142 
  2143 * Bugs fixed in the inductive definition and datatype packages;
  2144 
  2145 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2146 and HOL_dup_cs obsolete;
  2147 
  2148 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2149 have been removed;
  2150 
  2151 * Simpler definition of function space in ZF;
  2152 
  2153 * new results about cardinal and ordinal arithmetic in ZF;
  2154 
  2155 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2156 types;
  2157 
  2158 
  2159 $Id$