NEWS
author wenzelm
Sun Jan 13 21:12:43 2002 +0100 (2002-01-13)
changeset 12736 80f10551fb59
parent 12734 c5f6d8259ecd
child 12753 3a62df7ae926
permissions -rw-r--r--
* HOL: symbolic syntax for x^2 (numeral 2);
     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: symbolic syntax for x^2 (numeral 2);
   186 
   187 * HOL: the class of all HOL types is now called "type" rather than
   188 "term"; INCOMPATIBILITY, need to adapt references to this type class
   189 in axclass/classes, instance/arities, and (usually rare) occurrences
   190 in typings (of consts etc.); internally the class is called
   191 "HOL.type", ML programs should refer to HOLogic.typeS;
   192 
   193 * HOL/record package improvements:
   194   - new derived operations "fields" to build a partial record section,
   195     "extend" to promote a fixed record to a record scheme, and
   196     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   197     declared as simp by default;
   198   - shared operations ("more", "fields", etc.) now need to be always
   199     qualified) --- potential INCOMPATIBILITY;
   200   - removed "make_scheme" operations (use "make" with "extend") --
   201     INCOMPATIBILITY;
   202   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   203   - provides cases/induct rules for use with corresponding Isar
   204     methods (for concrete records, record schemes, concrete more
   205     parts, and schematic more parts -- in that order);
   206   - internal definitions directly based on a light-weight abstract
   207     theory of product types over typedef rather than datatype;
   208 
   209 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   210 
   211 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   212 (beware of argument permutation!);
   213 
   214 * HOL: linorder_less_split superseded by linorder_cases;
   215 
   216 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   217 to peripheral theory "Hilbert_Choice";
   218 
   219 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   220 in this (rare) case use:
   221 
   222   delSWrapper "split_all_tac"
   223   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   224 
   225 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   226 MAY FAIL;
   227 
   228 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   229 Isabelle's type classes, ^ on functions and relations has too general
   230 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   231 necessary to attach explicit type constraints;
   232 
   233 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   234 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   235 (eg "compI" -> "rel_compI").
   236 
   237 * HOL: syntax translations now work properly with numerals and records
   238 expressions;
   239 
   240 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   241 of "lam" -- INCOMPATIBILITY;
   242 
   243 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   244 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   245 renamed "Product_Type.unit";
   246 
   247 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   248 
   249 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   250 Florian Kammüller);
   251 
   252 * HOL/IMP: updated and converted to new-style theory format; several
   253 parts turned into readable document, with proper Isar proof texts and
   254 some explanations (by Gerwin Klein);
   255 
   256 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   257 
   258 * HOL-Hyperreal is now a logic image;
   259 
   260 
   261 *** HOLCF ***
   262 
   263 * Isar: consts/constdefs supports mixfix syntax for continuous
   264 operations;
   265 
   266 * Isar: domain package adapted to new-style theory format, e.g. see
   267 HOLCF/ex/Dnat.thy;
   268 
   269 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   270 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   271 lift.induct_tac, always use UU instead of Undef;
   272 
   273 * HOLCF/IMP: updated and converted to new-style theory;
   274 
   275 
   276 *** ZF ***
   277 
   278 * Isar: proper integration of logic-specific tools and packages,
   279 including theory commands '(co)inductive', '(co)datatype',
   280 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   281 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   282 
   283 * theory Main no longer includes AC; for the Axiom of Choice, base
   284 your theory on Main_ZFC;
   285 
   286 * the integer library now covers quotients and remainders, with many
   287 laws relating division to addition, multiplication, etc.;
   288 
   289 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   290 typeless version of the formalism;
   291 
   292 * ZF/IMP: updated and converted to new-style theory format;
   293 
   294 * ZF/Induct: new directory for examples of inductive definitions,
   295 including theory Multiset for multiset orderings; converted to
   296 new-style theory format;
   297 
   298 
   299 *** General ***
   300 
   301 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   302 variable proof controls level of detail: 0 = no proofs (only oracle
   303 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   304 also ref manual for further ML interfaces;
   305 
   306 * Pure/axclass: removed obsolete ML interface
   307 goal_subclass/goal_arity;
   308 
   309 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   310 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   311 separate tokens, so expressions involving minus need to be spaced
   312 properly;
   313 
   314 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   315 rather than "infixl" or "infixr";
   316 
   317 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   318 sort constraint specifications in type inference; e.g. "x::_::foo"
   319 ensures that the type of "x" is of sort "foo" (but not necessarily a
   320 type variable);
   321 
   322 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   323 control output of nested => (types); the default behavior is
   324 "type_brackets";
   325 
   326 * Pure/syntax: builtin parse translation for "_constify" turns valued
   327 tokens into AST constants;
   328 
   329 * Pure/syntax: prefer later declarations of translations and print
   330 translation functions; potential INCOMPATIBILITY: need to reverse
   331 multiple declarations for same syntax element constant;
   332 
   333 * Provers/classical: renamed addaltern to addafter, addSaltern to
   334 addSafter;
   335 
   336 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   337 as well;
   338 
   339 * system: tested support for MacOS X; should be able to get Isabelle +
   340 Proof General to work in a plain Terminal after installing Poly/ML
   341 (e.g. from the Isabelle distribution area) and GNU bash alone
   342 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   343 support requires further installations, e.g. from
   344 http://fink.sourceforge.net/);
   345 
   346 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   347 
   348 * system: Proof General keywords specification is now part of the
   349 Isabelle distribution (see etc/isar-keywords.el);
   350 
   351 * system: support for persistent Proof General sessions (refrain from
   352 outdating all loaded theories on startup); user may create writable
   353 logic images like this: ``isabelle -q HOL Test'';
   354 
   355 * system: smart selection of Isabelle process versus Isabelle
   356 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   357 run both "isabelle" and "Isabelle" even if file names are badly
   358 damaged (executable inspects the case of the first letter of its own
   359 name); added separate "isabelle-process" and "isabelle-interface";
   360 
   361 * system: refrain from any attempt at filtering input streams; no
   362 longer support ``8bit'' encoding of old isabelle font, instead proper
   363 iso-latin characters may now be used; the related isatools
   364 "symbolinput" and "nonascii" have disappeared as well;
   365 
   366 * system: removed old "xterm" interface (the print modes "xterm" and
   367 "xterm_color" are still available for direct use in a suitable
   368 terminal);
   369 
   370 
   371 
   372 New in Isabelle99-2 (February 2001)
   373 -----------------------------------
   374 
   375 *** Overview of INCOMPATIBILITIES ***
   376 
   377 * HOL: please note that theories in the Library and elsewhere often use the
   378 new-style (Isar) format; to refer to their theorems in an ML script you must
   379 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   380 
   381 * HOL: inductive package no longer splits induction rule aggressively,
   382 but only as far as specified by the introductions given; the old
   383 format may be recovered via ML function complete_split_rule or attribute
   384 'split_rule (complete)';
   385 
   386 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   387 gfp_Tarski to gfp_unfold;
   388 
   389 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   390 
   391 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   392 relation); infix "^^" has been renamed "``"; infix "``" has been
   393 renamed "`"; "univalent" has been renamed "single_valued";
   394 
   395 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   396 operation;
   397 
   398 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   399 
   400 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   401 
   402 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   403 consequence, it is no longer monotonic wrt. the local goal context
   404 (which is now passed through the inductive cases);
   405 
   406 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   407 \<gg> to \<ggreater>;
   408 
   409 
   410 *** Document preparation ***
   411 
   412 * \isabellestyle{NAME} selects version of Isabelle output (currently
   413 available: are "it" for near math-mode best-style output, "sl" for
   414 slanted text style, and "tt" for plain type-writer; if no
   415 \isabellestyle command is given, output is according to slanted
   416 type-writer);
   417 
   418 * support sub/super scripts (for single symbols only), input syntax is
   419 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   420 
   421 * some more standard symbols; see Appendix A of the system manual for
   422 the complete list of symbols defined in isabellesym.sty;
   423 
   424 * improved isabelle style files; more abstract symbol implementation
   425 (should now use \isamath{...} and \isatext{...} in custom symbol
   426 definitions);
   427 
   428 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   429 state; Note that presentation of goal states does not conform to
   430 actual human-readable proof documents.  Please do not include goal
   431 states into document output unless you really know what you are doing!
   432 
   433 * proper indentation of antiquoted output with proportional LaTeX
   434 fonts;
   435 
   436 * no_document ML operator temporarily disables LaTeX document
   437 generation;
   438 
   439 * isatool unsymbolize tunes sources for plain ASCII communication;
   440 
   441 
   442 *** Isar ***
   443 
   444 * Pure: Isar now suffers initial goal statements to contain unbound
   445 schematic variables (this does not conform to actual readable proof
   446 documents, due to unpredictable outcome and non-compositional proof
   447 checking); users who know what they are doing may use schematic goals
   448 for Prolog-style synthesis of proven results;
   449 
   450 * Pure: assumption method (an implicit finishing) now handles actual
   451 rules as well;
   452 
   453 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   454 initial goal, declare "that" only as Pure intro (only for single
   455 steps); the "that" rule assumption may now be involved in implicit
   456 finishing, thus ".." becomes a feasible for trivial obtains;
   457 
   458 * Pure: default proof step now includes 'intro_classes'; thus trivial
   459 instance proofs may be performed by "..";
   460 
   461 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   462 statements as well;
   463 
   464 * Pure: more robust selection of calculational rules;
   465 
   466 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   467 rule (as well as the assumption rule);
   468 
   469 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   470 lemmas, using the graph browser tool;
   471 
   472 * Pure: predict failure of "show" in interactive mode;
   473 
   474 * Pure: 'thms_containing' now takes actual terms as arguments;
   475 
   476 * HOL: improved method 'induct' --- now handles non-atomic goals
   477 (potential INCOMPATIBILITY); tuned error handling;
   478 
   479 * HOL: cases and induct rules now provide explicit hints about the
   480 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   481 any remaining facts are inserted into the goal verbatim;
   482 
   483 * HOL: local contexts (aka cases) may now contain term bindings as
   484 well; the 'cases' and 'induct' methods new provide a ?case binding for
   485 the result to be shown in each case;
   486 
   487 * HOL: added 'recdef_tc' command;
   488 
   489 * isatool convert assists in eliminating legacy ML scripts;
   490 
   491 
   492 *** HOL ***
   493 
   494 * HOL/Library: a collection of generic theories to be used together
   495 with main HOL; the theory loader path already includes this directory
   496 by default; the following existing theories have been moved here:
   497 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   498 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   499 
   500 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   501 modelling and verification task performed in Isabelle/HOL +
   502 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   503 
   504 * HOL/Algebra: special summation operator SUM no longer exists, it has
   505 been replaced by setsum; infix 'assoc' now has priority 50 (like
   506 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   507 'domain', this makes the theory consistent with mathematical
   508 literature;
   509 
   510 * HOL basics: added overloaded operations "inverse" and "divide"
   511 (infix "/"), syntax for generic "abs" operation, generic summation
   512 operator \<Sum>;
   513 
   514 * HOL/typedef: simplified package, provide more useful rules (see also
   515 HOL/subset.thy);
   516 
   517 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   518 now expressed as a proper nested rule (old-style tactic scripts may
   519 require atomize_strip_tac to cope with non-atomic premises);
   520 
   521 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   522 to "split_conv" (old name still available for compatibility);
   523 
   524 * HOL: improved concrete syntax for strings (e.g. allows translation
   525 rules with string literals);
   526 
   527 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   528  and Fleuriot's mechanization of analysis, including the transcendental
   529  functions for the reals;
   530 
   531 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   532 
   533 
   534 *** CTT ***
   535 
   536 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   537 "lam" is displayed as TWO lambda-symbols
   538 
   539 * CTT: theory Main now available, containing everything (that is, Bool
   540 and Arith);
   541 
   542 
   543 *** General ***
   544 
   545 * Pure: the Simplifier has been implemented properly as a derived rule
   546 outside of the actual kernel (at last!); the overall performance
   547 penalty in practical applications is about 50%, while reliability of
   548 the Isabelle inference kernel has been greatly improved;
   549 
   550 * print modes "brackets" and "no_brackets" control output of nested =>
   551 (types) and ==> (props); the default behaviour is "brackets";
   552 
   553 * Provers: fast_tac (and friends) now handle actual object-logic rules
   554 as assumptions as well;
   555 
   556 * system: support Poly/ML 4.0;
   557 
   558 * system: isatool install handles KDE version 1 or 2;
   559 
   560 
   561 
   562 New in Isabelle99-1 (October 2000)
   563 ----------------------------------
   564 
   565 *** Overview of INCOMPATIBILITIES ***
   566 
   567 * HOL: simplification of natural numbers is much changed; to partly
   568 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   569 issue the following ML commands:
   570 
   571   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   572   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   573 
   574 * HOL: simplification no longer dives into case-expressions; this is
   575 controlled by "t.weak_case_cong" for each datatype t;
   576 
   577 * HOL: nat_less_induct renamed to less_induct;
   578 
   579 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   580 fixsome to patch .thy and .ML sources automatically;
   581 
   582   select_equality  -> some_equality
   583   select_eq_Ex     -> some_eq_ex
   584   selectI2EX       -> someI2_ex
   585   selectI2         -> someI2
   586   selectI          -> someI
   587   select1_equality -> some1_equality
   588   Eps_sym_eq       -> some_sym_eq_trivial
   589   Eps_eq           -> some_eq_trivial
   590 
   591 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   592 
   593 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   594 instead);
   595 
   596 * HOL: the recursion equations generated by 'recdef' are now called
   597 f.simps instead of f.rules;
   598 
   599 * HOL: qed_spec_mp now also handles bounded ALL as well;
   600 
   601 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   602 sometimes be needed;
   603 
   604 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   605 
   606 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   607 
   608 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   609 product is now "<*>" instead of "Times"; the lexicographic product is
   610 now "<*lex*>" instead of "**";
   611 
   612 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   613 of main HOL, but was unused); better use HOL's datatype package;
   614 
   615 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   616 the old syntax may be recovered as follows:
   617 
   618   syntax (symbols)
   619     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   620       (infixl "\\<oplus>" 100)
   621 
   622 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   623 
   624 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   625 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   626 internally;
   627 
   628 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   629 changed from A/r to A//r;
   630 
   631 * ZF: new treatment of arithmetic (nat & int) may break some old
   632 proofs;
   633 
   634 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   635 rulify -> rule_format, elimify -> elim_format, ...);
   636 
   637 * Isar/Provers: intro/elim/dest attributes changed; renamed
   638 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   639 should have to change intro!! to intro? only); replaced "delrule" by
   640 "rule del";
   641 
   642 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   643 
   644 * Provers: strengthened force_tac by using new first_best_tac;
   645 
   646 * LaTeX document preparation: several changes of isabelle.sty (see
   647 lib/texinputs);
   648 
   649 
   650 *** Document preparation ***
   651 
   652 * formal comments (text blocks etc.) in new-style theories may now
   653 contain antiquotations of thm/prop/term/typ/text to be presented
   654 according to latex print mode; concrete syntax is like this:
   655 @{term[show_types] "f(x) = a + x"};
   656 
   657 * isatool mkdir provides easy setup of Isabelle session directories,
   658 including proper document sources;
   659 
   660 * generated LaTeX sources are now deleted after successful run
   661 (isatool document -c); may retain a copy somewhere else via -D option
   662 of isatool usedir;
   663 
   664 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   665 style files, achieving self-contained LaTeX sources and simplifying
   666 LaTeX debugging;
   667 
   668 * old-style theories now produce (crude) LaTeX output as well;
   669 
   670 * browser info session directories are now self-contained (may be put
   671 on WWW server seperately); improved graphs of nested sessions; removed
   672 graph for 'all sessions';
   673 
   674 * several improvements in isabelle style files; \isabellestyle{it}
   675 produces fake math mode output; \isamarkupheader is now \section by
   676 default; see lib/texinputs/isabelle.sty etc.;
   677 
   678 
   679 *** Isar ***
   680 
   681 * Isar/Pure: local results and corresponding term bindings are now
   682 subject to Hindley-Milner polymorphism (similar to ML); this
   683 accommodates incremental type-inference very nicely;
   684 
   685 * Isar/Pure: new derived language element 'obtain' supports
   686 generalized existence reasoning;
   687 
   688 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   689 support accumulation of results, without applying any rules yet;
   690 useful to collect intermediate results without explicit name
   691 references, and for use with transitivity rules with more than 2
   692 premises;
   693 
   694 * Isar/Pure: scalable support for case-analysis type proofs: new
   695 'case' language element refers to local contexts symbolically, as
   696 produced by certain proof methods; internally, case names are attached
   697 to theorems as "tags";
   698 
   699 * Isar/Pure: theory command 'hide' removes declarations from
   700 class/type/const name spaces;
   701 
   702 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   703 indicate potential overloading;
   704 
   705 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   706 
   707 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   708 "{a,b,c}" instead of {a,b,c};
   709 
   710 * Isar/Pure now provides its own version of intro/elim/dest
   711 attributes; useful for building new logics, but beware of confusion
   712 with the version in Provers/classical;
   713 
   714 * Isar/Pure: the local context of (non-atomic) goals is provided via
   715 case name 'antecedent';
   716 
   717 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   718 to the current context is now done automatically);
   719 
   720 * Isar/Pure: theory command 'method_setup' provides a simple interface
   721 for definining proof methods in ML;
   722 
   723 * Isar/Provers: intro/elim/dest attributes changed; renamed
   724 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   725 most cases, one should have to change intro!! to intro? only);
   726 replaced "delrule" by "rule del";
   727 
   728 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   729 'symmetric' attribute (the latter supercedes [RS sym]);
   730 
   731 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   732 method modifier); 'simp' method: 'only:' modifier removes loopers as
   733 well (including splits);
   734 
   735 * Isar/Provers: Simplifier and Classical methods now support all kind
   736 of modifiers used in the past, including 'cong', 'iff', etc.
   737 
   738 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   739 of Simplifier and Classical reasoner);
   740 
   741 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   742 now support named cases; major packages (inductive, datatype, primrec,
   743 recdef) support case names and properly name parameters;
   744 
   745 * Isar/HOL: new transitivity rules for substitution in inequalities --
   746 monotonicity conditions are extracted to be proven at end of
   747 calculations;
   748 
   749 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   750 method anyway;
   751 
   752 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   753 split_if split_if_asm; datatype package provides theorems foo.splits =
   754 foo.split foo.split_asm for each datatype;
   755 
   756 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   757 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   758 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   759 use "(cases (simplified))" method in proper proof texts);
   760 
   761 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   762 
   763 * Isar: names of theorems etc. may be natural numbers as well;
   764 
   765 * Isar: 'pr' command: optional arguments for goals_limit and
   766 ProofContext.prems_limit; no longer prints theory contexts, but only
   767 proof states;
   768 
   769 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   770 additional print modes to be specified; e.g. "pr(latex)" will print
   771 proof state according to the Isabelle LaTeX style;
   772 
   773 * Isar: improved support for emulating tactic scripts, including proof
   774 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   775 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   776 (for HOL datatypes);
   777 
   778 * Isar: simplified (more robust) goal selection of proof methods: 1st
   779 goal, all goals, or explicit goal specifier (tactic emulation); thus
   780 'proof method scripts' have to be in depth-first order;
   781 
   782 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   783 
   784 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   785 should instead use individual commands for printing items
   786 (print_commands, print_methods etc.);
   787 
   788 * Isar: added 'nothing' --- the empty list of theorems;
   789 
   790 
   791 *** HOL ***
   792 
   793 * HOL/MicroJava: formalization of a fragment of Java, together with a
   794 corresponding virtual machine and a specification of its bytecode
   795 verifier and a lightweight bytecode verifier, including proofs of
   796 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   797 Cornelia Pusch (see also the homepage of project Bali at
   798 http://isabelle.in.tum.de/Bali/);
   799 
   800 * HOL/Algebra: new theory of rings and univariate polynomials, by
   801 Clemens Ballarin;
   802 
   803 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   804 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   805 Rasmussen;
   806 
   807 * HOL/Lattice: fundamental concepts of lattice theory and order
   808 structures, including duals, properties of bounds versus algebraic
   809 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   810 Theorem for complete lattices etc.; may also serve as a demonstration
   811 for abstract algebraic reasoning using axiomatic type classes, and
   812 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   813 
   814 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   815 von Oheimb;
   816 
   817 * HOL/IMPP: extension of IMP with local variables and mutually
   818 recursive procedures, by David von Oheimb;
   819 
   820 * HOL/Lambda: converted into new-style theory and document;
   821 
   822 * HOL/ex/Multiquote: example of multiple nested quotations and
   823 anti-quotations -- basically a generalized version of de-Bruijn
   824 representation; very useful in avoiding lifting of operations;
   825 
   826 * HOL/record: added general record equality rule to simpset; fixed
   827 select-update simplification procedure to handle extended records as
   828 well; admit "r" as field name;
   829 
   830 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   831 other numeric types and also as the identity of groups, rings, etc.;
   832 
   833 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   834 Types nat and int belong to this axclass;
   835 
   836 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   837    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   838    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   839   two terms #m*u and #n*u are replaced by #(m+n)*u
   840     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   841   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   842     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   843 
   844 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   845 powerful prover for predicate logic but knows nothing of clasets; see
   846 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   847 
   848 * HOL: new version of "case_tac" subsumes both boolean case split and
   849 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   850 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   851 
   852 * HOL: simplification no longer dives into case-expressions: only the
   853 selector expression is simplified, but not the remaining arms; to
   854 enable full simplification of case-expressions for datatype t, you may
   855 remove t.weak_case_cong from the simpset, either globally (Delcongs
   856 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   857 
   858 * HOL/recdef: the recursion equations generated by 'recdef' for
   859 function 'f' are now called f.simps instead of f.rules; if all
   860 termination conditions are proved automatically, these simplification
   861 rules are added to the simpset, as in primrec; rules may be named
   862 individually as well, resulting in a separate list of theorems for
   863 each equation;
   864 
   865 * HOL/While is a new theory that provides a while-combinator. It
   866 permits the definition of tail-recursive functions without the
   867 provision of a termination measure. The latter is necessary once the
   868 invariant proof rule for while is applied.
   869 
   870 * HOL: new (overloaded) notation for the set of elements below/above
   871 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   872 
   873 * HOL: theorems impI, allI, ballI bound as "strip";
   874 
   875 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   876 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   877 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   878 
   879 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   880 
   881 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   882 main HOL, but was unused);
   883 
   884 * HOL: fewer consts declared as global (e.g. have to refer to
   885 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   886 
   887 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   888 in case of overlap with user translations (e.g. judgements over
   889 tuples); (note that the underlying logical represenation is still
   890 bogus);
   891 
   892 
   893 *** ZF ***
   894 
   895 * ZF: simplification automatically cancels common terms in arithmetic
   896 expressions over nat and int;
   897 
   898 * ZF: new treatment of nat to minimize type-checking: all operators
   899 coerce their operands to a natural number using the function natify,
   900 making the algebraic laws unconditional;
   901 
   902 * ZF: as above, for int: operators coerce their operands to an integer
   903 using the function intify;
   904 
   905 * ZF: the integer library now contains many of the usual laws for the
   906 orderings, including $<=, and monotonicity laws for $+ and $*;
   907 
   908 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   909 simplification;
   910 
   911 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   912 to the simplifier and classical reasoner simultaneously;
   913 
   914 
   915 *** General ***
   916 
   917 * Provers: blast_tac now handles actual object-logic rules as
   918 assumptions; note that auto_tac uses blast_tac internally as well;
   919 
   920 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   921 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   922 
   923 * Provers: delrules now handles destruct rules as well (no longer need
   924 explicit make_elim);
   925 
   926 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   927   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   928 use instead the strong form,
   929   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   930 in HOL, FOL and ZF the function cla_make_elim will create such rules
   931 from destruct-rules;
   932 
   933 * Provers: Simplifier.easy_setup provides a fast path to basic
   934 Simplifier setup for new object-logics;
   935 
   936 * Pure: AST translation rules no longer require constant head on LHS;
   937 
   938 * Pure: improved name spaces: ambiguous output is qualified; support
   939 for hiding of names;
   940 
   941 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   942 XSYMBOL_HOME; no longer need to do manual configuration in most
   943 situations;
   944 
   945 * system: compression of ML heaps images may now be controlled via -c
   946 option of isabelle and isatool usedir (currently only observed by
   947 Poly/ML);
   948 
   949 * system: isatool installfonts may handle X-Symbol fonts as well (very
   950 useful for remote X11);
   951 
   952 * system: provide TAGS file for Isabelle sources;
   953 
   954 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   955 order;
   956 
   957 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   958 timing flag supersedes proof_timing and Toplevel.trace;
   959 
   960 * ML: new combinators |>> and |>>> for incremental transformations
   961 with secondary results (e.g. certain theory extensions):
   962 
   963 * ML: PureThy.add_defs gets additional argument to indicate potential
   964 overloading (usually false);
   965 
   966 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   967 results;
   968 
   969 
   970 
   971 New in Isabelle99 (October 1999)
   972 --------------------------------
   973 
   974 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   975 
   976 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   977 are no longer simplified.  (This allows the simplifier to unfold recursive
   978 functional programs.)  To restore the old behaviour, declare
   979 
   980     Delcongs [if_weak_cong];
   981 
   982 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   983 complement;
   984 
   985 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   986 
   987 * HOL/datatype: mutual_induct_tac no longer exists --
   988   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   989 
   990 * HOL/typedef: fixed type inference for representing set; type
   991 arguments now have to occur explicitly on the rhs as type constraints;
   992 
   993 * ZF: The con_defs part of an inductive definition may no longer refer
   994 to constants declared in the same theory;
   995 
   996 * HOL, ZF: the function mk_cases, generated by the inductive
   997 definition package, has lost an argument.  To simplify its result, it
   998 uses the default simpset instead of a supplied list of theorems.
   999 
  1000 * HOL/List: the constructors of type list are now Nil and Cons;
  1001 
  1002 * Simplifier: the type of the infix ML functions
  1003         setSSolver addSSolver setSolver addSolver
  1004 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1005 for packaging solvers. A solver is created via
  1006         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1007 where the string argument is only a comment.
  1008 
  1009 
  1010 *** Proof tools ***
  1011 
  1012 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1013 decision procedure for linear arithmetic. Currently it is used for
  1014 types `nat', `int', and `real' in HOL (see below); it can, should and
  1015 will be instantiated for other types and logics as well.
  1016 
  1017 * The simplifier now accepts rewrite rules with flexible heads, eg
  1018      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1019   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1020   matching.
  1021 
  1022 
  1023 *** General ***
  1024 
  1025 * New Isabelle/Isar subsystem provides an alternative to traditional
  1026 tactical theorem proving; together with the ProofGeneral/isar user
  1027 interface it offers an interactive environment for developing human
  1028 readable proof documents (Isar == Intelligible semi-automated
  1029 reasoning); for further information see isatool doc isar-ref,
  1030 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1031 
  1032 * improved and simplified presentation of theories: better HTML markup
  1033 (including colors), graph views in several sizes; isatool usedir now
  1034 provides a proper interface for user theories (via -P option); actual
  1035 document preparation based on (PDF)LaTeX is available as well (for
  1036 new-style theories only); see isatool doc system for more information;
  1037 
  1038 * native support for Proof General, both for classic Isabelle and
  1039 Isabelle/Isar;
  1040 
  1041 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1042 using the graph browser tool;
  1043 
  1044 * Isabelle manuals now also available as PDF;
  1045 
  1046 * theory loader rewritten from scratch (may not be fully
  1047 bug-compatible); old loadpath variable has been replaced by show_path,
  1048 add_path, del_path, reset_path functions; new operations such as
  1049 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1050 isatool doc ref);
  1051 
  1052 * improved isatool install: option -k creates KDE application icon,
  1053 option -p DIR installs standalone binaries;
  1054 
  1055 * added ML_PLATFORM setting (useful for cross-platform installations);
  1056 more robust handling of platform specific ML images for SML/NJ;
  1057 
  1058 * the settings environment is now statically scoped, i.e. it is never
  1059 created again in sub-processes invoked from isabelle, isatool, or
  1060 Isabelle;
  1061 
  1062 * path element specification '~~' refers to '$ISABELLE_HOME';
  1063 
  1064 * in locales, the "assumes" and "defines" parts may be omitted if
  1065 empty;
  1066 
  1067 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1068 long arrows);
  1069 
  1070 * new print_mode "HTML";
  1071 
  1072 * new flag show_tags controls display of tags of theorems (which are
  1073 basically just comments that may be attached by some tools);
  1074 
  1075 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1076 mode and goal output format:
  1077 
  1078 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1079 244c244
  1080 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1081 ---
  1082 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1083 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1084 181c181
  1085 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1086 ---
  1087 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1088 
  1089 * function bind_thms stores lists of theorems (cf. bind_thm);
  1090 
  1091 * new shorthand tactics ftac, eatac, datac, fatac;
  1092 
  1093 * qed (and friends) now accept "" as result name; in that case the
  1094 theorem is not stored, but proper checks and presentation of the
  1095 result still apply;
  1096 
  1097 * theorem database now also indexes constants "Trueprop", "all",
  1098 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1099 
  1100 
  1101 *** HOL ***
  1102 
  1103 ** HOL arithmetic **
  1104 
  1105 * There are now decision procedures for linear arithmetic over nat and
  1106 int:
  1107 
  1108 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1109 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1110 are treated as atomic; subformulae not involving type `nat' or `int'
  1111 are ignored; quantified subformulae are ignored unless they are
  1112 positive universal or negative existential. The tactic has to be
  1113 invoked by hand and can be a little bit slow. In particular, the
  1114 running time is exponential in the number of occurrences of `min' and
  1115 `max', and `-' on `nat'.
  1116 
  1117 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1118 (negated) (in)equalities among the premises and the conclusion into
  1119 account (i.e. no compound formulae) and does not know about `min' and
  1120 `max', and `-' on `nat'. It is fast and is used automatically by the
  1121 simplifier.
  1122 
  1123 NB: At the moment, these decision procedures do not cope with mixed
  1124 nat/int formulae where the two parts interact, such as `m < n ==>
  1125 int(m) < int(n)'.
  1126 
  1127 * HOL/Numeral provides a generic theory of numerals (encoded
  1128 efficiently as bit strings); setup for types nat/int/real is in place;
  1129 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1130 int, existing theories and proof scripts may require a few additional
  1131 type constraints;
  1132 
  1133 * integer division and remainder can now be performed on constant
  1134 arguments;
  1135 
  1136 * many properties of integer multiplication, division and remainder
  1137 are now available;
  1138 
  1139 * An interface to the Stanford Validity Checker (SVC) is available through the
  1140 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1141 are proved automatically.  SVC must be installed separately, and its results
  1142 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1143 invocation of the underlying oracle).  For SVC see
  1144   http://verify.stanford.edu/SVC
  1145 
  1146 * IsaMakefile: the HOL-Real target now builds an actual image;
  1147 
  1148 
  1149 ** HOL misc **
  1150 
  1151 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1152 (in Isabelle/Isar) -- by Gertrud Bauer;
  1153 
  1154 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1155 analysis for assembly languages with subtypes;
  1156 
  1157 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1158 -- avoids syntactic ambiguities and treats state, transition, and
  1159 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1160 changed syntax and (many) tactics;
  1161 
  1162 * HOL/inductive: Now also handles more general introduction rules such
  1163   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1164   theorems are now maintained within the theory (maintained via the
  1165   "mono" attribute);
  1166 
  1167 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1168   (using function types) such as
  1169 
  1170   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1171 
  1172 * HOL/record: record_simproc (part of the default simpset) takes care
  1173 of selectors applied to updated records; record_split_tac is no longer
  1174 part of the default claset; update_defs may now be removed from the
  1175 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1176 
  1177   claset_ref () := claset() addSWrapper record_split_wrapper;
  1178   Delsimprocs [record_simproc]
  1179 
  1180 * HOL/typedef: fixed type inference for representing set; type
  1181 arguments now have to occur explicitly on the rhs as type constraints;
  1182 
  1183 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1184 names rather than an ML expression;
  1185 
  1186 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1187 supplied later.  Program schemes can be defined, such as
  1188     "While B C s = (if B s then While B C (C s) else s)"
  1189 where the well-founded relation can be chosen after B and C have been given.
  1190 
  1191 * HOL/List: the constructors of type list are now Nil and Cons;
  1192 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1193 course, ML tools referring to List.list.op # etc. have to be adapted;
  1194 
  1195 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1196 disabled by default; run isabelle with option -m HOL to get back to
  1197 the original Gordon/HOL-style output;
  1198 
  1199 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1200 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1201 
  1202 * HOL basic syntax simplified (more orthogonal): all variants of
  1203 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1204 Eps operator is provided as well: "SOME x. P[x]";
  1205 
  1206 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1207 
  1208 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1209 thus available for user theories;
  1210 
  1211 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1212 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1213 time;
  1214 
  1215 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1216 several times and then mp;
  1217 
  1218 
  1219 *** LK ***
  1220 
  1221 * the notation <<...>> is now available as a notation for sequences of
  1222 formulas;
  1223 
  1224 * the simplifier is now installed
  1225 
  1226 * the axiom system has been generalized (thanks to Soren Heilmann)
  1227 
  1228 * the classical reasoner now has a default rule database
  1229 
  1230 
  1231 *** ZF ***
  1232 
  1233 * new primrec section allows primitive recursive functions to be given
  1234 directly (as in HOL) over datatypes and the natural numbers;
  1235 
  1236 * new tactics induct_tac and exhaust_tac for induction (or case
  1237 analysis) over datatypes and the natural numbers;
  1238 
  1239 * the datatype declaration of type T now defines the recursor T_rec;
  1240 
  1241 * simplification automatically does freeness reasoning for datatype
  1242 constructors;
  1243 
  1244 * automatic type-inference, with AddTCs command to insert new
  1245 type-checking rules;
  1246 
  1247 * datatype introduction rules are now added as Safe Introduction rules
  1248 to the claset;
  1249 
  1250 * the syntax "if P then x else y" is now available in addition to
  1251 if(P,x,y);
  1252 
  1253 
  1254 *** Internal programming interfaces ***
  1255 
  1256 * tuned simplifier trace output; new flag debug_simp;
  1257 
  1258 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1259 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1260 
  1261 * AxClass.axclass_tac lost the theory argument;
  1262 
  1263 * tuned current_goals_markers semantics: begin / end goal avoids
  1264 printing empty lines;
  1265 
  1266 * removed prs and prs_fn hook, which was broken because it did not
  1267 include \n in its semantics, forcing writeln to add one
  1268 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1269 string -> unit if you really want to output text without newline;
  1270 
  1271 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1272 plain output, interface builders may have to enable 'isabelle_font'
  1273 mode to get Isabelle font glyphs as before;
  1274 
  1275 * refined token_translation interface; INCOMPATIBILITY: output length
  1276 now of type real instead of int;
  1277 
  1278 * theory loader actions may be traced via new ThyInfo.add_hook
  1279 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1280 your own database of information attached to *whole* theories -- as
  1281 opposed to intra-theory data slots offered via TheoryDataFun;
  1282 
  1283 * proper handling of dangling sort hypotheses (at last!);
  1284 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1285 extra sort hypotheses that can be witnessed from the type signature;
  1286 the force_strip_shyps flag is gone, any remaining shyps are simply
  1287 left in the theorem (with a warning issued by strip_shyps_warning);
  1288 
  1289 
  1290 
  1291 New in Isabelle98-1 (October 1998)
  1292 ----------------------------------
  1293 
  1294 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1295 
  1296 * several changes of automated proof tools;
  1297 
  1298 * HOL: major changes to the inductive and datatype packages, including
  1299 some minor incompatibilities of theory syntax;
  1300 
  1301 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1302 called `inj_on';
  1303 
  1304 * HOL: removed duplicate thms in Arith:
  1305   less_imp_add_less  should be replaced by  trans_less_add1
  1306   le_imp_add_le      should be replaced by  trans_le_add1
  1307 
  1308 * HOL: unary minus is now overloaded (new type constraints may be
  1309 required);
  1310 
  1311 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1312 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1313 now taken as an integer constant.
  1314 
  1315 * Pure: ML function 'theory_of' renamed to 'theory';
  1316 
  1317 
  1318 *** Proof tools ***
  1319 
  1320 * Simplifier:
  1321   1. Asm_full_simp_tac is now more aggressive.
  1322      1. It will sometimes reorient premises if that increases their power to
  1323         simplify.
  1324      2. It does no longer proceed strictly from left to right but may also
  1325         rotate premises to achieve further simplification.
  1326      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1327      old Asm_full_simp_tac in that it does not rotate premises.
  1328   2. The simplifier now knows a little bit about nat-arithmetic.
  1329 
  1330 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1331 allows for selected deletion of wrappers, by introduction of names for
  1332 wrapper functionals.  This implies that addbefore, addSbefore,
  1333 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1334 and that adding two tactics with the same name overwrites the first
  1335 one (emitting a warning).
  1336   type wrapper = (int -> tactic) -> (int -> tactic)
  1337   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1338   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1339   delWrapper, delSWrapper: claset *  string            -> claset
  1340   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1341 
  1342 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1343 semantics; addbefore now affects only the unsafe part of step_tac
  1344 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1345 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1346 by Force_tac;
  1347 
  1348 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1349 compWrapper; added safe wrapper (and access functions for it);
  1350 
  1351 * HOL/split_all_tac is now much faster and fails if there is nothing
  1352 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1353 and the names of the automatically generated variables have changed.
  1354 split_all_tac has moved within claset() from unsafe wrappers to safe
  1355 wrappers, which means that !!-bound variables are split much more
  1356 aggressively, and safe_tac and clarify_tac now split such variables.
  1357 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1358 Note: the same holds for record_split_tac, which does the job of
  1359 split_all_tac for record fields.
  1360 
  1361 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1362 permanently to the default simpset using Addsplits just like
  1363 Addsimps. They can be removed via Delsplits just like
  1364 Delsimps. Lower-case versions are also available.
  1365 
  1366 * HOL/Simplifier: The rule split_if is now part of the default
  1367 simpset. This means that the simplifier will eliminate all occurrences
  1368 of if-then-else in the conclusion of a goal. To prevent this, you can
  1369 either remove split_if completely from the default simpset by
  1370 `Delsplits [split_if]' or remove it in a specific call of the
  1371 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1372 other case splitting rules to/from the default simpset: every datatype
  1373 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1374 t is the name of the datatype).
  1375 
  1376 * Classical reasoner / Simplifier combination: new force_tac (and
  1377 derivatives Force_tac, force) combines rewriting and classical
  1378 reasoning (and whatever other tools) similarly to auto_tac, but is
  1379 aimed to solve the given subgoal completely.
  1380 
  1381 
  1382 *** General ***
  1383 
  1384 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1385 and `goalw': the theory is no longer needed as an explicit argument -
  1386 the current theory context is used; assumptions are no longer returned
  1387 at the ML-level unless one of them starts with ==> or !!; it is
  1388 recommended to convert to these new commands using isatool fixgoal
  1389 (backup your sources first!);
  1390 
  1391 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1392 the current theory context, and 'theory' to lookup stored theories;
  1393 
  1394 * new theory section 'locale' for declaring constants, assumptions and
  1395 definitions that have local scope;
  1396 
  1397 * new theory section 'nonterminals' for purely syntactic types;
  1398 
  1399 * new theory section 'setup' for generic ML setup functions
  1400 (e.g. package initialization);
  1401 
  1402 * the distribution now includes Isabelle icons: see
  1403 lib/logo/isabelle-{small,tiny}.xpm;
  1404 
  1405 * isatool install - install binaries with absolute references to
  1406 ISABELLE_HOME/bin;
  1407 
  1408 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1409 
  1410 * print mode 'emacs' reserved for Isamode;
  1411 
  1412 * support multiple print (ast) translations per constant name;
  1413 
  1414 * theorems involving oracles are now printed with a suffixed [!];
  1415 
  1416 
  1417 *** HOL ***
  1418 
  1419 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1420 
  1421 * HOL/inductive package reorganized and improved: now supports mutual
  1422 definitions such as
  1423 
  1424   inductive EVEN ODD
  1425     intrs
  1426       null "0 : EVEN"
  1427       oddI "n : EVEN ==> Suc n : ODD"
  1428       evenI "n : ODD ==> Suc n : EVEN"
  1429 
  1430 new theorem list "elims" contains an elimination rule for each of the
  1431 recursive sets; inductive definitions now handle disjunctive premises
  1432 correctly (also ZF);
  1433 
  1434 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1435 "mutual_induct" no longer exists - the induction rule is always
  1436 contained in "induct";
  1437 
  1438 
  1439 * HOL/datatype package re-implemented and greatly improved: now
  1440 supports mutually recursive datatypes such as
  1441 
  1442   datatype
  1443     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1444             | SUM ('a aexp) ('a aexp)
  1445             | DIFF ('a aexp) ('a aexp)
  1446             | NUM 'a
  1447   and
  1448     'a bexp = LESS ('a aexp) ('a aexp)
  1449             | AND ('a bexp) ('a bexp)
  1450             | OR ('a bexp) ('a bexp)
  1451 
  1452 as well as indirectly recursive datatypes such as
  1453 
  1454   datatype
  1455     ('a, 'b) term = Var 'a
  1456                   | App 'b ((('a, 'b) term) list)
  1457 
  1458 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1459 induction on mutually / indirectly recursive datatypes.
  1460 
  1461 Primrec equations are now stored in theory and can be accessed via
  1462 <function_name>.simps.
  1463 
  1464 INCOMPATIBILITIES:
  1465 
  1466   - Theories using datatypes must now have theory Datatype as an
  1467     ancestor.
  1468   - The specific <typename>.induct_tac no longer exists - use the
  1469     generic induct_tac instead.
  1470   - natE has been renamed to nat.exhaust - use exhaust_tac
  1471     instead of res_inst_tac ... natE. Note that the variable
  1472     names in nat.exhaust differ from the names in natE, this
  1473     may cause some "fragile" proofs to fail.
  1474   - The theorems split_<typename>_case and split_<typename>_case_asm
  1475     have been renamed to <typename>.split and <typename>.split_asm.
  1476   - Since default sorts of type variables are now handled correctly,
  1477     some datatype definitions may have to be annotated with explicit
  1478     sort constraints.
  1479   - Primrec definitions no longer require function name and type
  1480     of recursive argument.
  1481 
  1482 Consider using isatool fixdatatype to adapt your theories and proof
  1483 scripts to the new package (backup your sources first!).
  1484 
  1485 
  1486 * HOL/record package: considerably improved implementation; now
  1487 includes concrete syntax for record types, terms, updates; theorems
  1488 for surjective pairing and splitting !!-bound record variables; proof
  1489 support is as follows:
  1490 
  1491   1) standard conversions (selectors or updates applied to record
  1492 constructor terms) are part of the standard simpset;
  1493 
  1494   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1495 made part of standard simpset and claset via addIffs;
  1496 
  1497   3) a tactic for record field splitting (record_split_tac) is part of
  1498 the standard claset (addSWrapper);
  1499 
  1500 To get a better idea about these rules you may retrieve them via
  1501 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1502 the name of your record type.
  1503 
  1504 The split tactic 3) conceptually simplifies by the following rule:
  1505 
  1506   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1507 
  1508 Thus any record variable that is bound by meta-all will automatically
  1509 blow up into some record constructor term, consequently the
  1510 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1511 solve record problems automatically.
  1512 
  1513 
  1514 * reorganized the main HOL image: HOL/Integ and String loaded by
  1515 default; theory Main includes everything;
  1516 
  1517 * automatic simplification of integer sums and comparisons, using cancellation;
  1518 
  1519 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1520 
  1521 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1522 
  1523 * many new identities for unions, intersections, set difference, etc.;
  1524 
  1525 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1526 called split_if, split_split, split_sum_case and split_nat_case (to go
  1527 with add/delsplits);
  1528 
  1529 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1530 (?x::unit) = (); this is made part of the default simpset, which COULD
  1531 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1532 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1533 unit_abs_eta_conv is added in order to counter the effect of
  1534 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1535 %u.f();
  1536 
  1537 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1538 makes more sense);
  1539 
  1540 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1541   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1542   disjointness reasoning but breaking a few old proofs.
  1543 
  1544 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1545 to 'converse' from 'inverse' (for compatibility with ZF and some
  1546 literature);
  1547 
  1548 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1549 the well-founded relation;
  1550 
  1551 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1552     Compl A.  The "Compl" syntax remains available as input syntax for this
  1553     release ONLY.
  1554 
  1555 * HOL/Update: new theory of function updates:
  1556     f(a:=b) == %x. if x=a then b else f x
  1557 may also be iterated as in f(a:=b,c:=d,...);
  1558 
  1559 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1560 
  1561 * HOL/List:
  1562   - new function list_update written xs[i:=v] that updates the i-th
  1563     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1564   - new function `upt' written [i..j(] which generates the list
  1565     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1566     bound write [i..j], which is a shorthand for [i..j+1(].
  1567   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1568 
  1569 * HOL/Arith:
  1570   - removed 'pred' (predecessor) function;
  1571   - generalized some theorems about n-1;
  1572   - many new laws about "div" and "mod";
  1573   - new laws about greatest common divisors (see theory ex/Primes);
  1574 
  1575 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1576 instead of "inverse";
  1577 
  1578 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1579   of the multiset ordering;
  1580 
  1581 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1582   (not included by default);
  1583 
  1584 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1585 
  1586 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1587   programs, i.e. different program variables may have different types.
  1588 
  1589 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1590   [previously, this check worked only if the rewrite rule was unconditional]
  1591   Now rew can involve either definitions or equalities (either == or =).
  1592 
  1593 
  1594 *** ZF ***
  1595 
  1596 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1597   only the theorems proved on ZF.ML;
  1598 
  1599 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1600   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1601   disjointness reasoning but breaking a few old proofs.
  1602 
  1603 * ZF/Update: new theory of function updates
  1604     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1605   may also be iterated as in f(a:=b,c:=d,...);
  1606 
  1607 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1608 
  1609 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1610   [previously, this check worked only if the rewrite rule was unconditional]
  1611   Now rew can involve either definitions or equalities (either == or =).
  1612 
  1613 * case_tac provided for compatibility with HOL
  1614     (like the old excluded_middle_tac, but with subgoals swapped)
  1615 
  1616 
  1617 *** Internal programming interfaces ***
  1618 
  1619 * Pure: several new basic modules made available for general use, see
  1620 also src/Pure/README;
  1621 
  1622 * improved the theory data mechanism to support encapsulation (data
  1623 kind name replaced by private Object.kind, acting as authorization
  1624 key); new type-safe user interface via functor TheoryDataFun; generic
  1625 print_data function becomes basically useless;
  1626 
  1627 * removed global_names compatibility flag -- all theory declarations
  1628 are qualified by default;
  1629 
  1630 * module Pure/Syntax now offers quote / antiquote translation
  1631 functions (useful for Hoare logic etc. with implicit dependencies);
  1632 see HOL/ex/Antiquote for an example use;
  1633 
  1634 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1635 cterm -> thm;
  1636 
  1637 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1638 subgoal;
  1639 
  1640 * Display.print_goals function moved to Locale.print_goals;
  1641 
  1642 * standard print function for goals supports current_goals_markers
  1643 variable for marking begin of proof, end of proof, start of goal; the
  1644 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1645 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1646 for example;
  1647 
  1648 
  1649 
  1650 New in Isabelle98 (January 1998)
  1651 --------------------------------
  1652 
  1653 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1654 
  1655 * changed lexical syntax of terms / types: dots made part of long
  1656 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1657 
  1658 * simpset (and claset) reference variable replaced by functions
  1659 simpset / simpset_ref;
  1660 
  1661 * no longer supports theory aliases (via merge) and non-trivial
  1662 implicit merge of thms' signatures;
  1663 
  1664 * most internal names of constants changed due to qualified names;
  1665 
  1666 * changed Pure/Sequence interface (see Pure/seq.ML);
  1667 
  1668 
  1669 *** General Changes ***
  1670 
  1671 * hierachically structured name spaces (for consts, types, axms, thms
  1672 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1673 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1674 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1675 long_names for fully qualified output names; NOTE: ML programs
  1676 (special tactics, packages etc.) referring to internal names may have
  1677 to be adapted to cope with fully qualified names; in case of severe
  1678 backward campatibility problems try setting 'global_names' at compile
  1679 time to have enrything declared within a flat name space; one may also
  1680 fine tune name declarations in theories via the 'global' and 'local'
  1681 section;
  1682 
  1683 * reimplemented the implicit simpset and claset using the new anytype
  1684 data filed in signatures; references simpset:simpset ref etc. are
  1685 replaced by functions simpset:unit->simpset and
  1686 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1687 to patch your ML files accordingly;
  1688 
  1689 * HTML output now includes theory graph data for display with Java
  1690 applet or isatool browser; data generated automatically via isatool
  1691 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1692 
  1693 * defs may now be conditional; improved rewrite_goals_tac to handle
  1694 conditional equations;
  1695 
  1696 * defs now admits additional type arguments, using TYPE('a) syntax;
  1697 
  1698 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1699 creates a new theory node; implicit merge of thms' signatures is
  1700 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1701 transfer:theory->thm->thm in (rare) cases;
  1702 
  1703 * improved handling of draft signatures / theories; draft thms (and
  1704 ctyps, cterms) are automatically promoted to real ones;
  1705 
  1706 * slightly changed interfaces for oracles: admit many per theory, named
  1707 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1708 
  1709 * print_goals: optional output of const types (set show_consts and
  1710 show_types);
  1711 
  1712 * improved output of warnings (###) and errors (***);
  1713 
  1714 * subgoal_tac displays a warning if the new subgoal has type variables;
  1715 
  1716 * removed old README and Makefiles;
  1717 
  1718 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1719 
  1720 * removed obsolete init_pps and init_database;
  1721 
  1722 * deleted the obsolete tactical STATE, which was declared by
  1723     fun STATE tacfun st = tacfun st st;
  1724 
  1725 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1726 (which abbreviates $HOME);
  1727 
  1728 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1729 use isatool fixseq to adapt your ML programs (this works for fully
  1730 qualified references to the Sequence structure only!);
  1731 
  1732 * use_thy no longer requires writable current directory; it always
  1733 reloads .ML *and* .thy file, if either one is out of date;
  1734 
  1735 
  1736 *** Classical Reasoner ***
  1737 
  1738 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1739 tactics that use classical reasoning to simplify a subgoal without
  1740 splitting it into several subgoals;
  1741 
  1742 * Safe_tac: like safe_tac but uses the default claset;
  1743 
  1744 
  1745 *** Simplifier ***
  1746 
  1747 * added simplification meta rules:
  1748     (asm_)(full_)simplify: simpset -> thm -> thm;
  1749 
  1750 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1751 logics (again);
  1752 
  1753 * added prems argument to simplification procedures;
  1754 
  1755 * HOL, FOL, ZF: added infix function `addsplits':
  1756   instead of `<simpset> setloop (split_tac <thms>)'
  1757   you can simply write `<simpset> addsplits <thms>'
  1758 
  1759 
  1760 *** Syntax ***
  1761 
  1762 * TYPE('a) syntax for type reflection terms;
  1763 
  1764 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1765 
  1766 * pretty printer: changed order of mixfix annotation preference (again!);
  1767 
  1768 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1769 
  1770 
  1771 *** HOL ***
  1772 
  1773 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1774   with `addloop' of the simplifier to faciliate case splitting in premises.
  1775 
  1776 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1777 
  1778 * HOL/Auth: new protocol proofs including some for the Internet
  1779   protocol TLS;
  1780 
  1781 * HOL/Map: new theory of `maps' a la VDM;
  1782 
  1783 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1784 cancelling out common nat summands from =, <, <= (in)equalities, or
  1785 differences; simplification procedures nat_cancel_factor for
  1786 cancelling common factor from =, <, <= (in)equalities over natural
  1787 sums; nat_cancel contains both kinds of procedures, it is installed by
  1788 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1789 
  1790 * HOL/simplifier: terms of the form
  1791   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1792   are rewritten to
  1793   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1794   and those of the form
  1795   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1796   are rewritten to
  1797   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1798 
  1799 * HOL/datatype
  1800   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1801 
  1802   P(t_case f1 ... fn x) =
  1803      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1804         ...
  1805        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1806      )
  1807 
  1808   and a theorem `split_t_case_asm' of the form
  1809 
  1810   P(t_case f1 ... fn x) =
  1811     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1812         ...
  1813        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1814      )
  1815   which can be added to a simpset via `addsplits'. The existing theorems
  1816   expand_list_case and expand_option_case have been renamed to
  1817   split_list_case and split_option_case.
  1818 
  1819 * HOL/Arithmetic:
  1820   - `pred n' is automatically converted to `n-1'.
  1821     Users are strongly encouraged not to use `pred' any longer,
  1822     because it will disappear altogether at some point.
  1823   - Users are strongly encouraged to write "0 < n" rather than
  1824     "n ~= 0". Theorems and proof tools have been modified towards this
  1825     `standard'.
  1826 
  1827 * HOL/Lists:
  1828   the function "set_of_list" has been renamed "set" (and its theorems too);
  1829   the function "nth" now takes its arguments in the reverse order and
  1830   has acquired the infix notation "!" as in "xs!n".
  1831 
  1832 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1833 
  1834 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1835   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1836 
  1837 * HOL/record: extensible records with schematic structural subtyping
  1838 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1839 still lacks various theorems and concrete record syntax;
  1840 
  1841 
  1842 *** HOLCF ***
  1843 
  1844 * removed "axioms" and "generated by" sections;
  1845 
  1846 * replaced "ops" section by extended "consts" section, which is capable of
  1847   handling the continuous function space "->" directly;
  1848 
  1849 * domain package:
  1850   . proves theorems immediately and stores them in the theory,
  1851   . creates hierachical name space,
  1852   . now uses normal mixfix annotations (instead of cinfix...),
  1853   . minor changes to some names and values (for consistency),
  1854   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1855   . separator between mutual domain defs: changed "," to "and",
  1856   . improved handling of sort constraints;  now they have to
  1857     appear on the left-hand side of the equations only;
  1858 
  1859 * fixed LAM <x,y,zs>.b syntax;
  1860 
  1861 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1862 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1863 
  1864 
  1865 *** FOL and ZF ***
  1866 
  1867 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1868   with `addloop' of the simplifier to faciliate case splitting in premises.
  1869 
  1870 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1871 in HOL, they strip ALL and --> from proved theorems;
  1872 
  1873 
  1874 
  1875 New in Isabelle94-8 (May 1997)
  1876 ------------------------------
  1877 
  1878 *** General Changes ***
  1879 
  1880 * new utilities to build / run / maintain Isabelle etc. (in parts
  1881 still somewhat experimental); old Makefiles etc. still functional;
  1882 
  1883 * new 'Isabelle System Manual';
  1884 
  1885 * INSTALL text, together with ./configure and ./build scripts;
  1886 
  1887 * reimplemented type inference for greater efficiency, better error
  1888 messages and clean internal interface;
  1889 
  1890 * prlim command for dealing with lots of subgoals (an easier way of
  1891 setting goals_limit);
  1892 
  1893 
  1894 *** Syntax ***
  1895 
  1896 * supports alternative (named) syntax tables (parser and pretty
  1897 printer); internal interface is provided by add_modesyntax(_i);
  1898 
  1899 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1900 be used in conjunction with the Isabelle symbol font; uses the
  1901 "symbols" syntax table;
  1902 
  1903 * added token_translation interface (may translate name tokens in
  1904 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1905 the current print_mode); IMPORTANT: user print translation functions
  1906 are responsible for marking newly introduced bounds
  1907 (Syntax.mark_boundT);
  1908 
  1909 * token translations for modes "xterm" and "xterm_color" that display
  1910 names in bold, underline etc. or colors (which requires a color
  1911 version of xterm);
  1912 
  1913 * infixes may now be declared with names independent of their syntax;
  1914 
  1915 * added typed_print_translation (like print_translation, but may
  1916 access type of constant);
  1917 
  1918 
  1919 *** Classical Reasoner ***
  1920 
  1921 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1922 some limitations.  Blast_tac...
  1923   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1924   + ignores elimination rules that don't have the correct format
  1925         (the conclusion MUST be a formula variable)
  1926   + ignores types, which can make HOL proofs fail
  1927   + rules must not require higher-order unification, e.g. apply_type in ZF
  1928     [message "Function Var's argument not a bound variable" relates to this]
  1929   + its proof strategy is more general but can actually be slower
  1930 
  1931 * substitution with equality assumptions no longer permutes other
  1932 assumptions;
  1933 
  1934 * minor changes in semantics of addafter (now called addaltern); renamed
  1935 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1936 (and access functions for it);
  1937 
  1938 * improved combination of classical reasoner and simplifier:
  1939   + functions for handling clasimpsets
  1940   + improvement of addss: now the simplifier is called _after_ the
  1941     safe steps.
  1942   + safe variant of addss called addSss: uses safe simplifications
  1943     _during_ the safe steps. It is more complete as it allows multiple
  1944     instantiations of unknowns (e.g. with slow_tac).
  1945 
  1946 *** Simplifier ***
  1947 
  1948 * added interface for simplification procedures (functions that
  1949 produce *proven* rewrite rules on the fly, depending on current
  1950 redex);
  1951 
  1952 * ordering on terms as parameter (used for ordered rewriting);
  1953 
  1954 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1955 
  1956 * the solver is now split into a safe and an unsafe part.
  1957 This should be invisible for the normal user, except that the
  1958 functions setsolver and addsolver have been renamed to setSolver and
  1959 addSolver; added safe_asm_full_simp_tac;
  1960 
  1961 
  1962 *** HOL ***
  1963 
  1964 * a generic induction tactic `induct_tac' which works for all datatypes and
  1965 also for type `nat';
  1966 
  1967 * a generic case distinction tactic `exhaust_tac' which works for all
  1968 datatypes and also for type `nat';
  1969 
  1970 * each datatype comes with a function `size';
  1971 
  1972 * patterns in case expressions allow tuple patterns as arguments to
  1973 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1974 
  1975 * primrec now also works with type nat;
  1976 
  1977 * recdef: a new declaration form, allows general recursive functions to be
  1978 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1979 
  1980 * the constant for negation has been renamed from "not" to "Not" to
  1981 harmonize with FOL, ZF, LK, etc.;
  1982 
  1983 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1984 infinite lists;
  1985 
  1986 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1987 
  1988 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1989 problems in commutative rings, using axiomatic type classes for + and *;
  1990 
  1991 * more examples in HOL/MiniML and HOL/Auth;
  1992 
  1993 * more default rewrite rules for quantifiers, union/intersection;
  1994 
  1995 * a new constant `arbitrary == @x.False';
  1996 
  1997 * HOLCF/IOA replaces old HOL/IOA;
  1998 
  1999 * HOLCF changes: derived all rules and arities
  2000   + axiomatic type classes instead of classes
  2001   + typedef instead of faking type definitions
  2002   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2003   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2004   + eliminated the types void, one, tr
  2005   + use unit lift and bool lift (with translations) instead of one and tr
  2006   + eliminated blift from Lift3.thy (use Def instead of blift)
  2007   all eliminated rules are derived as theorems --> no visible changes ;
  2008 
  2009 
  2010 *** ZF ***
  2011 
  2012 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2013 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2014 as ZF_cs addSIs [equalityI];
  2015 
  2016 
  2017 
  2018 New in Isabelle94-7 (November 96)
  2019 ---------------------------------
  2020 
  2021 * allowing negative levels (as offsets) in prlev and choplev;
  2022 
  2023 * super-linear speedup for large simplifications;
  2024 
  2025 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2026 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2027 FAIL); can suppress it using the command Delsimps (ex_simps @
  2028 all_simps); De Morgan laws are also now included, by default;
  2029 
  2030 * improved printing of ==>  :  ~:
  2031 
  2032 * new object-logic "Sequents" adds linear logic, while replacing LK
  2033 and Modal (thanks to Sara Kalvala);
  2034 
  2035 * HOL/Auth: correctness proofs for authentication protocols;
  2036 
  2037 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2038 examples on HOL/Auth);
  2039 
  2040 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2041 the rewriter and classical reasoner simultaneously;
  2042 
  2043 * function uresult no longer returns theorems in "standard" format;
  2044 regain previous version by: val uresult = standard o uresult;
  2045 
  2046 
  2047 
  2048 New in Isabelle94-6
  2049 -------------------
  2050 
  2051 * oracles -- these establish an interface between Isabelle and trusted
  2052 external reasoners, which may deliver results as theorems;
  2053 
  2054 * proof objects (in particular record all uses of oracles);
  2055 
  2056 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2057 
  2058 * "constdefs" section in theory files;
  2059 
  2060 * "primrec" section (HOL) no longer requires names;
  2061 
  2062 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2063 
  2064 
  2065 
  2066 New in Isabelle94-5
  2067 -------------------
  2068 
  2069 * reduced space requirements;
  2070 
  2071 * automatic HTML generation from theories;
  2072 
  2073 * theory files no longer require "..." (quotes) around most types;
  2074 
  2075 * new examples, including two proofs of the Church-Rosser theorem;
  2076 
  2077 * non-curried (1994) version of HOL is no longer distributed;
  2078 
  2079 
  2080 
  2081 New in Isabelle94-4
  2082 -------------------
  2083 
  2084 * greatly reduced space requirements;
  2085 
  2086 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2087 
  2088 * searchable theorem database (see the section "Retrieving theorems" on
  2089 page 8 of the Reference Manual);
  2090 
  2091 * new examples, including Grabczewski's monumental case study of the
  2092 Axiom of Choice;
  2093 
  2094 * The previous version of HOL renamed to Old_HOL;
  2095 
  2096 * The new version of HOL (previously called CHOL) uses a curried syntax
  2097 for functions.  Application looks like f a b instead of f(a,b);
  2098 
  2099 * Mutually recursive inductive definitions finally work in HOL;
  2100 
  2101 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2102 translates to the operator "split";
  2103 
  2104 
  2105 
  2106 New in Isabelle94-3
  2107 -------------------
  2108 
  2109 * new infix operator, addss, allowing the classical reasoner to
  2110 perform simplification at each step of its search.  Example:
  2111         fast_tac (cs addss ss)
  2112 
  2113 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2114 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2115 look like (a,b) instead of <a,b>;
  2116 
  2117 * PLEASE NOTE: CHOL will eventually replace HOL!
  2118 
  2119 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2120 It translates to the operator "split".  A new theory of integers is available;
  2121 
  2122 * In ZF, integer numerals now denote two's-complement binary integers.
  2123 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2124 
  2125 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2126 of the Axiom of Choice;
  2127 
  2128 
  2129 
  2130 New in Isabelle94-2
  2131 -------------------
  2132 
  2133 * Significantly faster resolution;
  2134 
  2135 * the different sections in a .thy file can now be mixed and repeated
  2136 freely;
  2137 
  2138 * Database of theorems for FOL, HOL and ZF.  New
  2139 commands including qed, qed_goal and bind_thm store theorems in the database.
  2140 
  2141 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2142 a given theory (thms_of), or find out what theory a theorem was proved in
  2143 (theory_of_thm);
  2144 
  2145 * Bugs fixed in the inductive definition and datatype packages;
  2146 
  2147 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2148 and HOL_dup_cs obsolete;
  2149 
  2150 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2151 have been removed;
  2152 
  2153 * Simpler definition of function space in ZF;
  2154 
  2155 * new results about cardinal and ordinal arithmetic in ZF;
  2156 
  2157 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2158 types;
  2159 
  2160 
  2161 $Id$