NEWS
author wenzelm
Sat Dec 29 18:34:42 2001 +0100 (2001-12-29)
changeset 12608 2df381faa787
parent 12597 14822e4436bf
child 12622 7592926925d4
permissions -rw-r--r--
* ZF/IMP: updated and converted to new-style theory format;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle2001 (December 2001)
     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;
    31 
    32 
    33 *** Isar ***
    34 
    35 * Pure/Provers: improved proof by cases and induction;
    36   - 'case' command admits impromptu naming of parameters (such as
    37     "case (Suc n)");
    38   - 'induct' method divinates rule instantiation from the inductive
    39     claim; no longer requires excessive ?P bindings for proper
    40     instantiation of cases;
    41   - 'induct' method properly enumerates all possibilities of set/type
    42     rules; as a consequence facts may be also passed through *type*
    43     rules without further ado;
    44   - 'induct' method now derives symbolic cases from the *rulified*
    45     rule (before it used to rulify cases stemming from the internal
    46     atomized version); this means that the context of a non-atomic
    47     statement becomes is included in the hypothesis, avoiding the
    48     slightly cumbersome show "PROP ?case" form;
    49   - 'induct' may now use elim-style induction rules without chaining
    50     facts, using ``missing'' premises from the goal state; this allows
    51     rules stemming from inductive sets to be applied in unstructured
    52     scripts, while still benefitting from proper handling of non-atomic
    53     statements; NB: major inductive premises need to be put first, all
    54     the rest of the goal is passed through the induction;
    55   - 'induct' proper support for mutual induction involving non-atomic
    56     rule statements (uses the new concept of simultaneous goals, see
    57     below);
    58   - removed obsolete "(simplified)" and "(stripped)" options of methods;
    59   - added 'print_induct_rules' (covered by help item in Proof General > 3.3);
    60   - moved induct/cases attributes to Pure, methods to Provers;
    61   - generic method setup instantiated for FOL and HOL;
    62 
    63 * Pure: support multiple simultaneous goal statements, for example
    64 "have a: A and b: B" (same for 'theorem' etc.); being a pure
    65 meta-level mechanism, this acts as if several individual goals had
    66 been stated separately; in particular common proof methods need to be
    67 repeated in order to cover all claims; note that a single elimination
    68 step is *not* sufficient to establish the two conjunctions, so this
    69 fails:
    70 
    71   assume "A & B" then have A and B ..   (*".." fails*)
    72 
    73 better use "obtain" in situations as above; alternative refer to
    74 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
    75 
    76 * Pure: proper integration with ``locales''; unlike the original
    77 version by Florian Kammüller, Isar locales package high-level proof
    78 contexts rather than raw logical ones (e.g. we admit to include
    79 attributes everywhere); operations on locales include merge and
    80 rename; e.g. see HOL/ex/Locales.thy;
    81 
    82 * Pure: theory goals now support ad-hoc contexts, which are discharged
    83 in the result, as in ``lemma (assumes A and B) K: A .''; syntax
    84 coincides with that of a locale body;
    85 
    86 * Pure: renamed "antecedent" case to "rule_context";
    87 
    88 * Pure: added 'corollary' command;
    89 
    90 * Pure: fixed 'token_translation' command;
    91 
    92 * Pure: removed obsolete 'exported' attribute;
    93 
    94 * Pure: dummy pattern "_" in is/let is now automatically lifted over
    95 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
    96 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
    97 
    98 * Pure: method 'atomize' presents local goal premises as object-level
    99 statements (atomic meta-level propositions); setup controlled via
   100 rewrite rules declarations of 'atomize' attribute; example
   101 application: 'induct' method with proper rule statements in improper
   102 proof *scripts*;
   103 
   104 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   105 now consider the syntactic context of assumptions, giving a better
   106 chance to get type-inference of the arguments right (this is
   107 especially important for locales);
   108 
   109 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   110 mode;
   111 
   112 * Pure/obtain: the formal conclusion "thesis", being marked as
   113 ``internal'', may no longer be reference directly in the text;
   114 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   115 situations;
   116 
   117 * Pure: generic 'sym' attribute which declares a rule both as pure
   118 'elim?' and for the 'symmetric' operation;
   119 
   120 * Pure/Provers/classical: simplified integration with pure rule
   121 attributes and methods; the classical "intro?/elim?/dest?"
   122 declarations coincide with the pure ones; the "rule" method no longer
   123 includes classically swapped intros; "intro" and "elim" methods no
   124 longer pick rules from the context; also got rid of ML declarations
   125 AddXIs/AddXEs/AddXDs; all of this has some potential for
   126 INCOMPATIBILITY;
   127 
   128 * Provers/classical: attribute 'swapped' produces classical inversions
   129 of introduction rules;
   130 
   131 * Provers/simplifier: 'simplified' attribute may refer to explicit
   132 rules instead of full simplifier context; 'iff' attribute handles
   133 conditional rules;
   134 
   135 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   136 
   137 * HOL: 'recdef' now fails on unfinished automated proofs, use
   138 "(permissive)" option to recover old behavior;
   139 
   140 * HOL: 'inductive' no longer features separate (collective) attributes
   141 for 'intros' (was found too confusing);
   142 
   143 * HOL: properly declared induction rules less_induct and
   144 wf_induct_rule;
   145 
   146 * HOLCF: domain package adapted to new-style theory format, e.g. see
   147 HOLCF/ex/Dnat.thy;
   148 
   149 * ZF: proper integration of logic-specific tools and packages,
   150 including theory commands '(co)inductive', '(co)datatype',
   151 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   152 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   153 
   154 
   155 *** HOL ***
   156 
   157 * HOL: moved over to sane numeral syntax; the new policy is as
   158 follows:
   159 
   160   - 0 and 1 are polymorphic constants, which are defined on any
   161   numeric type (nat, int, real etc.);
   162 
   163   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   164   binary representation internally;
   165 
   166   - type nat has special constructor Suc, and generally prefers Suc 0
   167   over 1::nat and Suc (Suc 0) over 2::nat;
   168 
   169 This change may cause significant problems of INCOMPATIBILITY; here
   170 are some hints on converting existing sources:
   171 
   172   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   173   entities, so expressions involving "-" (unary or binary minus) need
   174   to be spaced properly;
   175 
   176   - existing occurrences of "1" may need to be constraint "1::nat" or
   177   even replaced by Suc 0; similar for old "2";
   178 
   179   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   180 
   181   - remove all special provisions on numerals in proofs;
   182 
   183 * HOL: the class of all HOL types is now called "type" rather than
   184 "term"; INCOMPATIBILITY, need to adapt references to this type class
   185 in axclass/classes, instance/arities, and (usually rare) occurrences
   186 in typings (of consts etc.); internally the class is called
   187 "HOL.type", ML programs should refer to HOLogic.typeS;
   188 
   189 * HOL/record package improvements:
   190   - new derived operations "fields" to build a partial record section,
   191     "extend" to promote a fixed record to a record scheme, and
   192     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   193     declared as simp by default;
   194   - shared operations ("more", "fields", etc.) now need to be always
   195     qualified) --- potential INCOMPATIBILITY;
   196   - removed "make_scheme" operations (use "make" with "extend") --
   197     INCOMPATIBILITY;
   198   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   199   - provides cases/induct rules for use with corresponding Isar
   200     methods (for concrete records, record schemes, concrete more
   201     parts, and schematic more parts -- in that order);
   202   - internal definitions directly based on a light-weight abstract
   203     theory of product types over typedef rather than datatype;
   204 
   205 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   206 
   207 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   208 (beware of argument permutation!);
   209 
   210 * HOL: linorder_less_split superseded by linorder_cases;
   211 
   212 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   213 to peripheral theory "Hilbert_Choice";
   214 
   215 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   216 in this (rare) case use:
   217 
   218   delSWrapper "split_all_tac"
   219   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   220 
   221 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   222 MAY FAIL;
   223 
   224 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   225 Isabelle's type classes, ^ on functions and relations has too general
   226 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   227 necessary to attach explicit type constraints;
   228 
   229 * HOL/Relation: the prefix name of the infix "O" has been changed from "comp"
   230 to "rel_comp"; INCOMPATIBILITY: a few theorems have been renamed accordingly
   231 (eg "compI" -> "rel_compI").
   232 
   233 * HOL: syntax translations now work properly with numerals and records
   234 expressions;
   235 
   236 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   237 of "lam" -- INCOMPATIBILITY;
   238 
   239 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   240 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   241 renamed "Product_Type.unit";
   242 
   243 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   244 
   245 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   246 Florian Kammüller);
   247 
   248 * HOL/IMP: updated and converted to new-style theory format; several
   249 parts turned into readable document, with proper Isar proof texts and
   250 some explanations (by Gerwin Klein);
   251 
   252 
   253 *** HOLCF ***
   254 
   255 * proper rep_datatype lift (see theory Lift) instead of ML hacks --
   256 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   257 lift.induct_tac, always use UU instead of Undef;
   258 
   259 * HOLCF/IMP: updated and converted to new-style theory;
   260 
   261 
   262 *** ZF ***
   263 
   264 * Theory Main no longer includes AC; for the Axiom of Choice, base your 
   265 theory on Main_ZFC;
   266 
   267 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   268 typeless version of the formalism;
   269 
   270 * ZF/IMP: updated and converted to new-style theory format;
   271 
   272 * ZF/Induct: new directory for examples of inductive definitions,
   273 including theory Multiset for multiset orderings; converted to
   274 new-style theory format;
   275 
   276 * ZF: the integer library now covers quotients and remainders, with
   277 many laws relating division to addition, multiplication, etc.;
   278 
   279 
   280 *** General ***
   281 
   282 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   283 variable proof controls level of detail: 0 = no proofs (only oracle
   284 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   285 also ref manual for further ML interfaces;
   286 
   287 * Pure/axclass: removed obsolete ML interface
   288 goal_subclass/goal_arity;
   289 
   290 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   291 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   292 separate tokens, so expressions involving minus need to be spaced
   293 properly;
   294 
   295 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   296 rather than "infixl" or "infixr";
   297 
   298 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   299 sort constraint specifications in type inference; e.g. "x::_::foo"
   300 ensures that the type of "x" is of sort "foo" (but not necessarily a
   301 type variable);
   302 
   303 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   304 control output of nested => (types); the default behavior is
   305 "type_brackets";
   306 
   307 * Pure/syntax: builtin parse translation for "_constify" turns valued
   308 tokens into AST constants;
   309 
   310 * Pure/syntax: prefer later declarations of translations and print
   311 translation functions; potential INCOMPATIBILITY: need to reverse
   312 multiple declarations for same syntax element constant;
   313 
   314 * Provers/classical: renamed addaltern to addafter, addSaltern to
   315 addSafter;
   316 
   317 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   318 as well;
   319 
   320 * system: tested support for MacOS X; should be able to get Isabelle +
   321 Proof General to work in a plain Terminal after installing Poly/ML
   322 (e.g. from the Isabelle distribution area) and GNU bash alone
   323 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   324 support requires further installations, e.g. from
   325 http://fink.sourceforge.net/);
   326 
   327 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   328 
   329 * system: Proof General keywords specification is now part of the
   330 Isabelle distribution (see etc/isar-keywords.el);
   331 
   332 * system: some support for persistent Proof General sessions (refrain
   333 from outdating all loaded theories on startup);
   334 
   335 * system: smart selection of Isabelle process versus Isabelle
   336 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   337 run both "isabelle" and "Isabelle" even if file names are badly
   338 damaged (executable inspects the case of the first letter of its own
   339 name); added separate "isabelle-process" and "isabelle-interface";
   340 
   341 * system: refrain from any attempt at filtering input streams; no
   342 longer support ``8bit'' encoding of old isabelle font, instead proper
   343 iso-latin characters may now be used; the related isatools
   344 "symbolinput" and "nonascii" have disappeared as well;
   345 
   346 * system: removed old "xterm" interface (the print modes "xterm" and
   347 "xterm_color" are still available for direct use in a suitable
   348 terminal);
   349 
   350 
   351 
   352 New in Isabelle99-2 (February 2001)
   353 -----------------------------------
   354 
   355 *** Overview of INCOMPATIBILITIES ***
   356 
   357 * HOL: please note that theories in the Library and elsewhere often use the
   358 new-style (Isar) format; to refer to their theorems in an ML script you must
   359 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   360 
   361 * HOL: inductive package no longer splits induction rule aggressively,
   362 but only as far as specified by the introductions given; the old
   363 format may be recovered via ML function complete_split_rule or attribute
   364 'split_rule (complete)';
   365 
   366 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   367 gfp_Tarski to gfp_unfold;
   368 
   369 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   370 
   371 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   372 relation); infix "^^" has been renamed "``"; infix "``" has been
   373 renamed "`"; "univalent" has been renamed "single_valued";
   374 
   375 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   376 operation;
   377 
   378 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   379 
   380 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   381 
   382 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   383 consequence, it is no longer monotonic wrt. the local goal context
   384 (which is now passed through the inductive cases);
   385 
   386 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   387 \<gg> to \<ggreater>;
   388 
   389 
   390 *** Document preparation ***
   391 
   392 * \isabellestyle{NAME} selects version of Isabelle output (currently
   393 available: are "it" for near math-mode best-style output, "sl" for
   394 slanted text style, and "tt" for plain type-writer; if no
   395 \isabellestyle command is given, output is according to slanted
   396 type-writer);
   397 
   398 * support sub/super scripts (for single symbols only), input syntax is
   399 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   400 
   401 * some more standard symbols; see Appendix A of the system manual for
   402 the complete list of symbols defined in isabellesym.sty;
   403 
   404 * improved isabelle style files; more abstract symbol implementation
   405 (should now use \isamath{...} and \isatext{...} in custom symbol
   406 definitions);
   407 
   408 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   409 state; Note that presentation of goal states does not conform to
   410 actual human-readable proof documents.  Please do not include goal
   411 states into document output unless you really know what you are doing!
   412 
   413 * proper indentation of antiquoted output with proportional LaTeX
   414 fonts;
   415 
   416 * no_document ML operator temporarily disables LaTeX document
   417 generation;
   418 
   419 * isatool unsymbolize tunes sources for plain ASCII communication;
   420 
   421 
   422 *** Isar ***
   423 
   424 * Pure: Isar now suffers initial goal statements to contain unbound
   425 schematic variables (this does not conform to actual readable proof
   426 documents, due to unpredictable outcome and non-compositional proof
   427 checking); users who know what they are doing may use schematic goals
   428 for Prolog-style synthesis of proven results;
   429 
   430 * Pure: assumption method (an implicit finishing) now handles actual
   431 rules as well;
   432 
   433 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   434 initial goal, declare "that" only as Pure intro (only for single
   435 steps); the "that" rule assumption may now be involved in implicit
   436 finishing, thus ".." becomes a feasible for trivial obtains;
   437 
   438 * Pure: default proof step now includes 'intro_classes'; thus trivial
   439 instance proofs may be performed by "..";
   440 
   441 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   442 statements as well;
   443 
   444 * Pure: more robust selection of calculational rules;
   445 
   446 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   447 rule (as well as the assumption rule);
   448 
   449 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   450 lemmas, using the graph browser tool;
   451 
   452 * Pure: predict failure of "show" in interactive mode;
   453 
   454 * Pure: 'thms_containing' now takes actual terms as arguments;
   455 
   456 * HOL: improved method 'induct' --- now handles non-atomic goals
   457 (potential INCOMPATIBILITY); tuned error handling;
   458 
   459 * HOL: cases and induct rules now provide explicit hints about the
   460 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   461 any remaining facts are inserted into the goal verbatim;
   462 
   463 * HOL: local contexts (aka cases) may now contain term bindings as
   464 well; the 'cases' and 'induct' methods new provide a ?case binding for
   465 the result to be shown in each case;
   466 
   467 * HOL: added 'recdef_tc' command;
   468 
   469 * isatool convert assists in eliminating legacy ML scripts;
   470 
   471 
   472 *** HOL ***
   473 
   474 * HOL/Library: a collection of generic theories to be used together
   475 with main HOL; the theory loader path already includes this directory
   476 by default; the following existing theories have been moved here:
   477 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   478 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   479 
   480 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   481 modelling and verification task performed in Isabelle/HOL +
   482 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   483 
   484 * HOL/Algebra: special summation operator SUM no longer exists, it has
   485 been replaced by setsum; infix 'assoc' now has priority 50 (like
   486 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   487 'domain', this makes the theory consistent with mathematical
   488 literature;
   489 
   490 * HOL basics: added overloaded operations "inverse" and "divide"
   491 (infix "/"), syntax for generic "abs" operation, generic summation
   492 operator \<Sum>;
   493 
   494 * HOL/typedef: simplified package, provide more useful rules (see also
   495 HOL/subset.thy);
   496 
   497 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   498 now expressed as a proper nested rule (old-style tactic scripts may
   499 require atomize_strip_tac to cope with non-atomic premises);
   500 
   501 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   502 to "split_conv" (old name still available for compatibility);
   503 
   504 * HOL: improved concrete syntax for strings (e.g. allows translation
   505 rules with string literals);
   506 
   507 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   508  and Fleuriot's mechanization of analysis, including the transcendental
   509  functions for the reals;
   510 
   511 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   512 
   513 
   514 *** CTT ***
   515 
   516 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   517 "lam" is displayed as TWO lambda-symbols
   518 
   519 * CTT: theory Main now available, containing everything (that is, Bool
   520 and Arith);
   521 
   522 
   523 *** General ***
   524 
   525 * Pure: the Simplifier has been implemented properly as a derived rule
   526 outside of the actual kernel (at last!); the overall performance
   527 penalty in practical applications is about 50%, while reliability of
   528 the Isabelle inference kernel has been greatly improved;
   529 
   530 * print modes "brackets" and "no_brackets" control output of nested =>
   531 (types) and ==> (props); the default behaviour is "brackets";
   532 
   533 * Provers: fast_tac (and friends) now handle actual object-logic rules
   534 as assumptions as well;
   535 
   536 * system: support Poly/ML 4.0;
   537 
   538 * system: isatool install handles KDE version 1 or 2;
   539 
   540 
   541 
   542 New in Isabelle99-1 (October 2000)
   543 ----------------------------------
   544 
   545 *** Overview of INCOMPATIBILITIES ***
   546 
   547 * HOL: simplification of natural numbers is much changed; to partly
   548 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   549 issue the following ML commands:
   550 
   551   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   552   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   553 
   554 * HOL: simplification no longer dives into case-expressions; this is
   555 controlled by "t.weak_case_cong" for each datatype t;
   556 
   557 * HOL: nat_less_induct renamed to less_induct;
   558 
   559 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   560 fixsome to patch .thy and .ML sources automatically;
   561 
   562   select_equality  -> some_equality
   563   select_eq_Ex     -> some_eq_ex
   564   selectI2EX       -> someI2_ex
   565   selectI2         -> someI2
   566   selectI          -> someI
   567   select1_equality -> some1_equality
   568   Eps_sym_eq       -> some_sym_eq_trivial
   569   Eps_eq           -> some_eq_trivial
   570 
   571 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   572 
   573 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   574 instead);
   575 
   576 * HOL: the recursion equations generated by 'recdef' are now called
   577 f.simps instead of f.rules;
   578 
   579 * HOL: qed_spec_mp now also handles bounded ALL as well;
   580 
   581 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   582 sometimes be needed;
   583 
   584 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   585 
   586 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   587 
   588 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   589 product is now "<*>" instead of "Times"; the lexicographic product is
   590 now "<*lex*>" instead of "**";
   591 
   592 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   593 of main HOL, but was unused); better use HOL's datatype package;
   594 
   595 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   596 the old syntax may be recovered as follows:
   597 
   598   syntax (symbols)
   599     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   600       (infixl "\\<oplus>" 100)
   601 
   602 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   603 
   604 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   605 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   606 internally;
   607 
   608 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   609 changed from A/r to A//r;
   610 
   611 * ZF: new treatment of arithmetic (nat & int) may break some old
   612 proofs;
   613 
   614 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   615 rulify -> rule_format, elimify -> elim_format, ...);
   616 
   617 * Isar/Provers: intro/elim/dest attributes changed; renamed
   618 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   619 should have to change intro!! to intro? only); replaced "delrule" by
   620 "rule del";
   621 
   622 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   623 
   624 * Provers: strengthened force_tac by using new first_best_tac;
   625 
   626 * LaTeX document preparation: several changes of isabelle.sty (see
   627 lib/texinputs);
   628 
   629 
   630 *** Document preparation ***
   631 
   632 * formal comments (text blocks etc.) in new-style theories may now
   633 contain antiquotations of thm/prop/term/typ/text to be presented
   634 according to latex print mode; concrete syntax is like this:
   635 @{term[show_types] "f(x) = a + x"};
   636 
   637 * isatool mkdir provides easy setup of Isabelle session directories,
   638 including proper document sources;
   639 
   640 * generated LaTeX sources are now deleted after successful run
   641 (isatool document -c); may retain a copy somewhere else via -D option
   642 of isatool usedir;
   643 
   644 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   645 style files, achieving self-contained LaTeX sources and simplifying
   646 LaTeX debugging;
   647 
   648 * old-style theories now produce (crude) LaTeX output as well;
   649 
   650 * browser info session directories are now self-contained (may be put
   651 on WWW server seperately); improved graphs of nested sessions; removed
   652 graph for 'all sessions';
   653 
   654 * several improvements in isabelle style files; \isabellestyle{it}
   655 produces fake math mode output; \isamarkupheader is now \section by
   656 default; see lib/texinputs/isabelle.sty etc.;
   657 
   658 
   659 *** Isar ***
   660 
   661 * Isar/Pure: local results and corresponding term bindings are now
   662 subject to Hindley-Milner polymorphism (similar to ML); this
   663 accommodates incremental type-inference very nicely;
   664 
   665 * Isar/Pure: new derived language element 'obtain' supports
   666 generalized existence reasoning;
   667 
   668 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   669 support accumulation of results, without applying any rules yet;
   670 useful to collect intermediate results without explicit name
   671 references, and for use with transitivity rules with more than 2
   672 premises;
   673 
   674 * Isar/Pure: scalable support for case-analysis type proofs: new
   675 'case' language element refers to local contexts symbolically, as
   676 produced by certain proof methods; internally, case names are attached
   677 to theorems as "tags";
   678 
   679 * Isar/Pure: theory command 'hide' removes declarations from
   680 class/type/const name spaces;
   681 
   682 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   683 indicate potential overloading;
   684 
   685 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   686 
   687 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   688 "{a,b,c}" instead of {a,b,c};
   689 
   690 * Isar/Pure now provides its own version of intro/elim/dest
   691 attributes; useful for building new logics, but beware of confusion
   692 with the version in Provers/classical;
   693 
   694 * Isar/Pure: the local context of (non-atomic) goals is provided via
   695 case name 'antecedent';
   696 
   697 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   698 to the current context is now done automatically);
   699 
   700 * Isar/Pure: theory command 'method_setup' provides a simple interface
   701 for definining proof methods in ML;
   702 
   703 * Isar/Provers: intro/elim/dest attributes changed; renamed
   704 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   705 most cases, one should have to change intro!! to intro? only);
   706 replaced "delrule" by "rule del";
   707 
   708 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   709 'symmetric' attribute (the latter supercedes [RS sym]);
   710 
   711 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   712 method modifier); 'simp' method: 'only:' modifier removes loopers as
   713 well (including splits);
   714 
   715 * Isar/Provers: Simplifier and Classical methods now support all kind
   716 of modifiers used in the past, including 'cong', 'iff', etc.
   717 
   718 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   719 of Simplifier and Classical reasoner);
   720 
   721 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   722 now support named cases; major packages (inductive, datatype, primrec,
   723 recdef) support case names and properly name parameters;
   724 
   725 * Isar/HOL: new transitivity rules for substitution in inequalities --
   726 monotonicity conditions are extracted to be proven at end of
   727 calculations;
   728 
   729 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   730 method anyway;
   731 
   732 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   733 split_if split_if_asm; datatype package provides theorems foo.splits =
   734 foo.split foo.split_asm for each datatype;
   735 
   736 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   737 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   738 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   739 use "(cases (simplified))" method in proper proof texts);
   740 
   741 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   742 
   743 * Isar: names of theorems etc. may be natural numbers as well;
   744 
   745 * Isar: 'pr' command: optional arguments for goals_limit and
   746 ProofContext.prems_limit; no longer prints theory contexts, but only
   747 proof states;
   748 
   749 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   750 additional print modes to be specified; e.g. "pr(latex)" will print
   751 proof state according to the Isabelle LaTeX style;
   752 
   753 * Isar: improved support for emulating tactic scripts, including proof
   754 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   755 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   756 (for HOL datatypes);
   757 
   758 * Isar: simplified (more robust) goal selection of proof methods: 1st
   759 goal, all goals, or explicit goal specifier (tactic emulation); thus
   760 'proof method scripts' have to be in depth-first order;
   761 
   762 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   763 
   764 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   765 should instead use individual commands for printing items
   766 (print_commands, print_methods etc.);
   767 
   768 * Isar: added 'nothing' --- the empty list of theorems;
   769 
   770 
   771 *** HOL ***
   772 
   773 * HOL/MicroJava: formalization of a fragment of Java, together with a
   774 corresponding virtual machine and a specification of its bytecode
   775 verifier and a lightweight bytecode verifier, including proofs of
   776 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   777 Cornelia Pusch (see also the homepage of project Bali at
   778 http://isabelle.in.tum.de/Bali/);
   779 
   780 * HOL/Algebra: new theory of rings and univariate polynomials, by
   781 Clemens Ballarin;
   782 
   783 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   784 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   785 Rasmussen;
   786 
   787 * HOL/Lattice: fundamental concepts of lattice theory and order
   788 structures, including duals, properties of bounds versus algebraic
   789 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   790 Theorem for complete lattices etc.; may also serve as a demonstration
   791 for abstract algebraic reasoning using axiomatic type classes, and
   792 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   793 
   794 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   795 von Oheimb;
   796 
   797 * HOL/IMPP: extension of IMP with local variables and mutually
   798 recursive procedures, by David von Oheimb;
   799 
   800 * HOL/Lambda: converted into new-style theory and document;
   801 
   802 * HOL/ex/Multiquote: example of multiple nested quotations and
   803 anti-quotations -- basically a generalized version of de-Bruijn
   804 representation; very useful in avoiding lifting of operations;
   805 
   806 * HOL/record: added general record equality rule to simpset; fixed
   807 select-update simplification procedure to handle extended records as
   808 well; admit "r" as field name;
   809 
   810 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   811 other numeric types and also as the identity of groups, rings, etc.;
   812 
   813 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   814 Types nat and int belong to this axclass;
   815 
   816 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   817    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   818    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   819   two terms #m*u and #n*u are replaced by #(m+n)*u
   820     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   821   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   822     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   823 
   824 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   825 powerful prover for predicate logic but knows nothing of clasets; see
   826 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   827 
   828 * HOL: new version of "case_tac" subsumes both boolean case split and
   829 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   830 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   831 
   832 * HOL: simplification no longer dives into case-expressions: only the
   833 selector expression is simplified, but not the remaining arms; to
   834 enable full simplification of case-expressions for datatype t, you may
   835 remove t.weak_case_cong from the simpset, either globally (Delcongs
   836 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   837 
   838 * HOL/recdef: the recursion equations generated by 'recdef' for
   839 function 'f' are now called f.simps instead of f.rules; if all
   840 termination conditions are proved automatically, these simplification
   841 rules are added to the simpset, as in primrec; rules may be named
   842 individually as well, resulting in a separate list of theorems for
   843 each equation;
   844 
   845 * HOL/While is a new theory that provides a while-combinator. It
   846 permits the definition of tail-recursive functions without the
   847 provision of a termination measure. The latter is necessary once the
   848 invariant proof rule for while is applied.
   849 
   850 * HOL: new (overloaded) notation for the set of elements below/above
   851 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   852 
   853 * HOL: theorems impI, allI, ballI bound as "strip";
   854 
   855 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   856 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   857 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   858 
   859 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   860 
   861 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   862 main HOL, but was unused);
   863 
   864 * HOL: fewer consts declared as global (e.g. have to refer to
   865 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   866 
   867 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   868 in case of overlap with user translations (e.g. judgements over
   869 tuples); (note that the underlying logical represenation is still
   870 bogus);
   871 
   872 
   873 *** ZF ***
   874 
   875 * ZF: simplification automatically cancels common terms in arithmetic
   876 expressions over nat and int;
   877 
   878 * ZF: new treatment of nat to minimize type-checking: all operators
   879 coerce their operands to a natural number using the function natify,
   880 making the algebraic laws unconditional;
   881 
   882 * ZF: as above, for int: operators coerce their operands to an integer
   883 using the function intify;
   884 
   885 * ZF: the integer library now contains many of the usual laws for the
   886 orderings, including $<=, and monotonicity laws for $+ and $*;
   887 
   888 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   889 simplification;
   890 
   891 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   892 to the simplifier and classical reasoner simultaneously;
   893 
   894 
   895 *** General ***
   896 
   897 * Provers: blast_tac now handles actual object-logic rules as
   898 assumptions; note that auto_tac uses blast_tac internally as well;
   899 
   900 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   901 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   902 
   903 * Provers: delrules now handles destruct rules as well (no longer need
   904 explicit make_elim);
   905 
   906 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   907   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   908 use instead the strong form,
   909   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   910 in HOL, FOL and ZF the function cla_make_elim will create such rules
   911 from destruct-rules;
   912 
   913 * Provers: Simplifier.easy_setup provides a fast path to basic
   914 Simplifier setup for new object-logics;
   915 
   916 * Pure: AST translation rules no longer require constant head on LHS;
   917 
   918 * Pure: improved name spaces: ambiguous output is qualified; support
   919 for hiding of names;
   920 
   921 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   922 XSYMBOL_HOME; no longer need to do manual configuration in most
   923 situations;
   924 
   925 * system: compression of ML heaps images may now be controlled via -c
   926 option of isabelle and isatool usedir (currently only observed by
   927 Poly/ML);
   928 
   929 * system: isatool installfonts may handle X-Symbol fonts as well (very
   930 useful for remote X11);
   931 
   932 * system: provide TAGS file for Isabelle sources;
   933 
   934 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   935 order;
   936 
   937 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   938 timing flag supersedes proof_timing and Toplevel.trace;
   939 
   940 * ML: new combinators |>> and |>>> for incremental transformations
   941 with secondary results (e.g. certain theory extensions):
   942 
   943 * ML: PureThy.add_defs gets additional argument to indicate potential
   944 overloading (usually false);
   945 
   946 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   947 results;
   948 
   949 
   950 
   951 New in Isabelle99 (October 1999)
   952 --------------------------------
   953 
   954 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   955 
   956 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   957 are no longer simplified.  (This allows the simplifier to unfold recursive
   958 functional programs.)  To restore the old behaviour, declare
   959 
   960     Delcongs [if_weak_cong];
   961 
   962 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   963 complement;
   964 
   965 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   966 
   967 * HOL/datatype: mutual_induct_tac no longer exists --
   968   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   969 
   970 * HOL/typedef: fixed type inference for representing set; type
   971 arguments now have to occur explicitly on the rhs as type constraints;
   972 
   973 * ZF: The con_defs part of an inductive definition may no longer refer
   974 to constants declared in the same theory;
   975 
   976 * HOL, ZF: the function mk_cases, generated by the inductive
   977 definition package, has lost an argument.  To simplify its result, it
   978 uses the default simpset instead of a supplied list of theorems.
   979 
   980 * HOL/List: the constructors of type list are now Nil and Cons;
   981 
   982 * Simplifier: the type of the infix ML functions
   983         setSSolver addSSolver setSolver addSolver
   984 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   985 for packaging solvers. A solver is created via
   986         mk_solver: string -> (thm list -> int -> tactic) -> solver
   987 where the string argument is only a comment.
   988 
   989 
   990 *** Proof tools ***
   991 
   992 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   993 decision procedure for linear arithmetic. Currently it is used for
   994 types `nat', `int', and `real' in HOL (see below); it can, should and
   995 will be instantiated for other types and logics as well.
   996 
   997 * The simplifier now accepts rewrite rules with flexible heads, eg
   998      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   999   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1000   matching.
  1001 
  1002 
  1003 *** General ***
  1004 
  1005 * New Isabelle/Isar subsystem provides an alternative to traditional
  1006 tactical theorem proving; together with the ProofGeneral/isar user
  1007 interface it offers an interactive environment for developing human
  1008 readable proof documents (Isar == Intelligible semi-automated
  1009 reasoning); for further information see isatool doc isar-ref,
  1010 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1011 
  1012 * improved and simplified presentation of theories: better HTML markup
  1013 (including colors), graph views in several sizes; isatool usedir now
  1014 provides a proper interface for user theories (via -P option); actual
  1015 document preparation based on (PDF)LaTeX is available as well (for
  1016 new-style theories only); see isatool doc system for more information;
  1017 
  1018 * native support for Proof General, both for classic Isabelle and
  1019 Isabelle/Isar;
  1020 
  1021 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1022 using the graph browser tool;
  1023 
  1024 * Isabelle manuals now also available as PDF;
  1025 
  1026 * theory loader rewritten from scratch (may not be fully
  1027 bug-compatible); old loadpath variable has been replaced by show_path,
  1028 add_path, del_path, reset_path functions; new operations such as
  1029 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1030 isatool doc ref);
  1031 
  1032 * improved isatool install: option -k creates KDE application icon,
  1033 option -p DIR installs standalone binaries;
  1034 
  1035 * added ML_PLATFORM setting (useful for cross-platform installations);
  1036 more robust handling of platform specific ML images for SML/NJ;
  1037 
  1038 * the settings environment is now statically scoped, i.e. it is never
  1039 created again in sub-processes invoked from isabelle, isatool, or
  1040 Isabelle;
  1041 
  1042 * path element specification '~~' refers to '$ISABELLE_HOME';
  1043 
  1044 * in locales, the "assumes" and "defines" parts may be omitted if
  1045 empty;
  1046 
  1047 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1048 long arrows);
  1049 
  1050 * new print_mode "HTML";
  1051 
  1052 * new flag show_tags controls display of tags of theorems (which are
  1053 basically just comments that may be attached by some tools);
  1054 
  1055 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1056 mode and goal output format:
  1057 
  1058 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1059 244c244
  1060 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1061 ---
  1062 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1063 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1064 181c181
  1065 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1066 ---
  1067 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1068 
  1069 * function bind_thms stores lists of theorems (cf. bind_thm);
  1070 
  1071 * new shorthand tactics ftac, eatac, datac, fatac;
  1072 
  1073 * qed (and friends) now accept "" as result name; in that case the
  1074 theorem is not stored, but proper checks and presentation of the
  1075 result still apply;
  1076 
  1077 * theorem database now also indexes constants "Trueprop", "all",
  1078 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1079 
  1080 
  1081 *** HOL ***
  1082 
  1083 ** HOL arithmetic **
  1084 
  1085 * There are now decision procedures for linear arithmetic over nat and
  1086 int:
  1087 
  1088 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1089 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1090 are treated as atomic; subformulae not involving type `nat' or `int'
  1091 are ignored; quantified subformulae are ignored unless they are
  1092 positive universal or negative existential. The tactic has to be
  1093 invoked by hand and can be a little bit slow. In particular, the
  1094 running time is exponential in the number of occurrences of `min' and
  1095 `max', and `-' on `nat'.
  1096 
  1097 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1098 (negated) (in)equalities among the premises and the conclusion into
  1099 account (i.e. no compound formulae) and does not know about `min' and
  1100 `max', and `-' on `nat'. It is fast and is used automatically by the
  1101 simplifier.
  1102 
  1103 NB: At the moment, these decision procedures do not cope with mixed
  1104 nat/int formulae where the two parts interact, such as `m < n ==>
  1105 int(m) < int(n)'.
  1106 
  1107 * HOL/Numeral provides a generic theory of numerals (encoded
  1108 efficiently as bit strings); setup for types nat/int/real is in place;
  1109 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1110 int, existing theories and proof scripts may require a few additional
  1111 type constraints;
  1112 
  1113 * integer division and remainder can now be performed on constant
  1114 arguments;
  1115 
  1116 * many properties of integer multiplication, division and remainder
  1117 are now available;
  1118 
  1119 * An interface to the Stanford Validity Checker (SVC) is available through the
  1120 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1121 are proved automatically.  SVC must be installed separately, and its results
  1122 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1123 invocation of the underlying oracle).  For SVC see
  1124   http://verify.stanford.edu/SVC
  1125 
  1126 * IsaMakefile: the HOL-Real target now builds an actual image;
  1127 
  1128 
  1129 ** HOL misc **
  1130 
  1131 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1132 (in Isabelle/Isar) -- by Gertrud Bauer;
  1133 
  1134 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1135 analysis for assembly languages with subtypes;
  1136 
  1137 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1138 -- avoids syntactic ambiguities and treats state, transition, and
  1139 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1140 changed syntax and (many) tactics;
  1141 
  1142 * HOL/inductive: Now also handles more general introduction rules such
  1143   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1144   theorems are now maintained within the theory (maintained via the
  1145   "mono" attribute);
  1146 
  1147 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1148   (using function types) such as
  1149 
  1150   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1151 
  1152 * HOL/record: record_simproc (part of the default simpset) takes care
  1153 of selectors applied to updated records; record_split_tac is no longer
  1154 part of the default claset; update_defs may now be removed from the
  1155 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1156 
  1157   claset_ref () := claset() addSWrapper record_split_wrapper;
  1158   Delsimprocs [record_simproc]
  1159 
  1160 * HOL/typedef: fixed type inference for representing set; type
  1161 arguments now have to occur explicitly on the rhs as type constraints;
  1162 
  1163 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1164 names rather than an ML expression;
  1165 
  1166 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1167 supplied later.  Program schemes can be defined, such as
  1168     "While B C s = (if B s then While B C (C s) else s)"
  1169 where the well-founded relation can be chosen after B and C have been given.
  1170 
  1171 * HOL/List: the constructors of type list are now Nil and Cons;
  1172 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1173 course, ML tools referring to List.list.op # etc. have to be adapted;
  1174 
  1175 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1176 disabled by default; run isabelle with option -m HOL to get back to
  1177 the original Gordon/HOL-style output;
  1178 
  1179 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1180 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1181 
  1182 * HOL basic syntax simplified (more orthogonal): all variants of
  1183 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1184 Eps operator is provided as well: "SOME x. P[x]";
  1185 
  1186 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1187 
  1188 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1189 thus available for user theories;
  1190 
  1191 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1192 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1193 time;
  1194 
  1195 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1196 several times and then mp;
  1197 
  1198 
  1199 *** LK ***
  1200 
  1201 * the notation <<...>> is now available as a notation for sequences of
  1202 formulas;
  1203 
  1204 * the simplifier is now installed
  1205 
  1206 * the axiom system has been generalized (thanks to Soren Heilmann)
  1207 
  1208 * the classical reasoner now has a default rule database
  1209 
  1210 
  1211 *** ZF ***
  1212 
  1213 * new primrec section allows primitive recursive functions to be given
  1214 directly (as in HOL) over datatypes and the natural numbers;
  1215 
  1216 * new tactics induct_tac and exhaust_tac for induction (or case
  1217 analysis) over datatypes and the natural numbers;
  1218 
  1219 * the datatype declaration of type T now defines the recursor T_rec;
  1220 
  1221 * simplification automatically does freeness reasoning for datatype
  1222 constructors;
  1223 
  1224 * automatic type-inference, with AddTCs command to insert new
  1225 type-checking rules;
  1226 
  1227 * datatype introduction rules are now added as Safe Introduction rules
  1228 to the claset;
  1229 
  1230 * the syntax "if P then x else y" is now available in addition to
  1231 if(P,x,y);
  1232 
  1233 
  1234 *** Internal programming interfaces ***
  1235 
  1236 * tuned simplifier trace output; new flag debug_simp;
  1237 
  1238 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1239 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1240 
  1241 * AxClass.axclass_tac lost the theory argument;
  1242 
  1243 * tuned current_goals_markers semantics: begin / end goal avoids
  1244 printing empty lines;
  1245 
  1246 * removed prs and prs_fn hook, which was broken because it did not
  1247 include \n in its semantics, forcing writeln to add one
  1248 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1249 string -> unit if you really want to output text without newline;
  1250 
  1251 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1252 plain output, interface builders may have to enable 'isabelle_font'
  1253 mode to get Isabelle font glyphs as before;
  1254 
  1255 * refined token_translation interface; INCOMPATIBILITY: output length
  1256 now of type real instead of int;
  1257 
  1258 * theory loader actions may be traced via new ThyInfo.add_hook
  1259 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1260 your own database of information attached to *whole* theories -- as
  1261 opposed to intra-theory data slots offered via TheoryDataFun;
  1262 
  1263 * proper handling of dangling sort hypotheses (at last!);
  1264 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1265 extra sort hypotheses that can be witnessed from the type signature;
  1266 the force_strip_shyps flag is gone, any remaining shyps are simply
  1267 left in the theorem (with a warning issued by strip_shyps_warning);
  1268 
  1269 
  1270 
  1271 New in Isabelle98-1 (October 1998)
  1272 ----------------------------------
  1273 
  1274 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1275 
  1276 * several changes of automated proof tools;
  1277 
  1278 * HOL: major changes to the inductive and datatype packages, including
  1279 some minor incompatibilities of theory syntax;
  1280 
  1281 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1282 called `inj_on';
  1283 
  1284 * HOL: removed duplicate thms in Arith:
  1285   less_imp_add_less  should be replaced by  trans_less_add1
  1286   le_imp_add_le      should be replaced by  trans_le_add1
  1287 
  1288 * HOL: unary minus is now overloaded (new type constraints may be
  1289 required);
  1290 
  1291 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1292 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1293 now taken as an integer constant.
  1294 
  1295 * Pure: ML function 'theory_of' renamed to 'theory';
  1296 
  1297 
  1298 *** Proof tools ***
  1299 
  1300 * Simplifier:
  1301   1. Asm_full_simp_tac is now more aggressive.
  1302      1. It will sometimes reorient premises if that increases their power to
  1303         simplify.
  1304      2. It does no longer proceed strictly from left to right but may also
  1305         rotate premises to achieve further simplification.
  1306      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1307      old Asm_full_simp_tac in that it does not rotate premises.
  1308   2. The simplifier now knows a little bit about nat-arithmetic.
  1309 
  1310 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1311 allows for selected deletion of wrappers, by introduction of names for
  1312 wrapper functionals.  This implies that addbefore, addSbefore,
  1313 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1314 and that adding two tactics with the same name overwrites the first
  1315 one (emitting a warning).
  1316   type wrapper = (int -> tactic) -> (int -> tactic)
  1317   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1318   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1319   delWrapper, delSWrapper: claset *  string            -> claset
  1320   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1321 
  1322 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1323 semantics; addbefore now affects only the unsafe part of step_tac
  1324 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1325 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1326 by Force_tac;
  1327 
  1328 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1329 compWrapper; added safe wrapper (and access functions for it);
  1330 
  1331 * HOL/split_all_tac is now much faster and fails if there is nothing
  1332 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1333 and the names of the automatically generated variables have changed.
  1334 split_all_tac has moved within claset() from unsafe wrappers to safe
  1335 wrappers, which means that !!-bound variables are split much more
  1336 aggressively, and safe_tac and clarify_tac now split such variables.
  1337 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1338 Note: the same holds for record_split_tac, which does the job of
  1339 split_all_tac for record fields.
  1340 
  1341 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1342 permanently to the default simpset using Addsplits just like
  1343 Addsimps. They can be removed via Delsplits just like
  1344 Delsimps. Lower-case versions are also available.
  1345 
  1346 * HOL/Simplifier: The rule split_if is now part of the default
  1347 simpset. This means that the simplifier will eliminate all occurrences
  1348 of if-then-else in the conclusion of a goal. To prevent this, you can
  1349 either remove split_if completely from the default simpset by
  1350 `Delsplits [split_if]' or remove it in a specific call of the
  1351 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1352 other case splitting rules to/from the default simpset: every datatype
  1353 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1354 t is the name of the datatype).
  1355 
  1356 * Classical reasoner / Simplifier combination: new force_tac (and
  1357 derivatives Force_tac, force) combines rewriting and classical
  1358 reasoning (and whatever other tools) similarly to auto_tac, but is
  1359 aimed to solve the given subgoal completely.
  1360 
  1361 
  1362 *** General ***
  1363 
  1364 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1365 and `goalw': the theory is no longer needed as an explicit argument -
  1366 the current theory context is used; assumptions are no longer returned
  1367 at the ML-level unless one of them starts with ==> or !!; it is
  1368 recommended to convert to these new commands using isatool fixgoal
  1369 (backup your sources first!);
  1370 
  1371 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1372 the current theory context, and 'theory' to lookup stored theories;
  1373 
  1374 * new theory section 'locale' for declaring constants, assumptions and
  1375 definitions that have local scope;
  1376 
  1377 * new theory section 'nonterminals' for purely syntactic types;
  1378 
  1379 * new theory section 'setup' for generic ML setup functions
  1380 (e.g. package initialization);
  1381 
  1382 * the distribution now includes Isabelle icons: see
  1383 lib/logo/isabelle-{small,tiny}.xpm;
  1384 
  1385 * isatool install - install binaries with absolute references to
  1386 ISABELLE_HOME/bin;
  1387 
  1388 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1389 
  1390 * print mode 'emacs' reserved for Isamode;
  1391 
  1392 * support multiple print (ast) translations per constant name;
  1393 
  1394 * theorems involving oracles are now printed with a suffixed [!];
  1395 
  1396 
  1397 *** HOL ***
  1398 
  1399 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1400 
  1401 * HOL/inductive package reorganized and improved: now supports mutual
  1402 definitions such as
  1403 
  1404   inductive EVEN ODD
  1405     intrs
  1406       null "0 : EVEN"
  1407       oddI "n : EVEN ==> Suc n : ODD"
  1408       evenI "n : ODD ==> Suc n : EVEN"
  1409 
  1410 new theorem list "elims" contains an elimination rule for each of the
  1411 recursive sets; inductive definitions now handle disjunctive premises
  1412 correctly (also ZF);
  1413 
  1414 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1415 "mutual_induct" no longer exists - the induction rule is always
  1416 contained in "induct";
  1417 
  1418 
  1419 * HOL/datatype package re-implemented and greatly improved: now
  1420 supports mutually recursive datatypes such as
  1421 
  1422   datatype
  1423     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1424             | SUM ('a aexp) ('a aexp)
  1425             | DIFF ('a aexp) ('a aexp)
  1426             | NUM 'a
  1427   and
  1428     'a bexp = LESS ('a aexp) ('a aexp)
  1429             | AND ('a bexp) ('a bexp)
  1430             | OR ('a bexp) ('a bexp)
  1431 
  1432 as well as indirectly recursive datatypes such as
  1433 
  1434   datatype
  1435     ('a, 'b) term = Var 'a
  1436                   | App 'b ((('a, 'b) term) list)
  1437 
  1438 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1439 induction on mutually / indirectly recursive datatypes.
  1440 
  1441 Primrec equations are now stored in theory and can be accessed via
  1442 <function_name>.simps.
  1443 
  1444 INCOMPATIBILITIES:
  1445 
  1446   - Theories using datatypes must now have theory Datatype as an
  1447     ancestor.
  1448   - The specific <typename>.induct_tac no longer exists - use the
  1449     generic induct_tac instead.
  1450   - natE has been renamed to nat.exhaust - use exhaust_tac
  1451     instead of res_inst_tac ... natE. Note that the variable
  1452     names in nat.exhaust differ from the names in natE, this
  1453     may cause some "fragile" proofs to fail.
  1454   - The theorems split_<typename>_case and split_<typename>_case_asm
  1455     have been renamed to <typename>.split and <typename>.split_asm.
  1456   - Since default sorts of type variables are now handled correctly,
  1457     some datatype definitions may have to be annotated with explicit
  1458     sort constraints.
  1459   - Primrec definitions no longer require function name and type
  1460     of recursive argument.
  1461 
  1462 Consider using isatool fixdatatype to adapt your theories and proof
  1463 scripts to the new package (backup your sources first!).
  1464 
  1465 
  1466 * HOL/record package: considerably improved implementation; now
  1467 includes concrete syntax for record types, terms, updates; theorems
  1468 for surjective pairing and splitting !!-bound record variables; proof
  1469 support is as follows:
  1470 
  1471   1) standard conversions (selectors or updates applied to record
  1472 constructor terms) are part of the standard simpset;
  1473 
  1474   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1475 made part of standard simpset and claset via addIffs;
  1476 
  1477   3) a tactic for record field splitting (record_split_tac) is part of
  1478 the standard claset (addSWrapper);
  1479 
  1480 To get a better idea about these rules you may retrieve them via
  1481 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1482 the name of your record type.
  1483 
  1484 The split tactic 3) conceptually simplifies by the following rule:
  1485 
  1486   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1487 
  1488 Thus any record variable that is bound by meta-all will automatically
  1489 blow up into some record constructor term, consequently the
  1490 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1491 solve record problems automatically.
  1492 
  1493 
  1494 * reorganized the main HOL image: HOL/Integ and String loaded by
  1495 default; theory Main includes everything;
  1496 
  1497 * automatic simplification of integer sums and comparisons, using cancellation;
  1498 
  1499 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1500 
  1501 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1502 
  1503 * many new identities for unions, intersections, set difference, etc.;
  1504 
  1505 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1506 called split_if, split_split, split_sum_case and split_nat_case (to go
  1507 with add/delsplits);
  1508 
  1509 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1510 (?x::unit) = (); this is made part of the default simpset, which COULD
  1511 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1512 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1513 unit_abs_eta_conv is added in order to counter the effect of
  1514 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1515 %u.f();
  1516 
  1517 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1518 makes more sense);
  1519 
  1520 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1521   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1522   disjointness reasoning but breaking a few old proofs.
  1523 
  1524 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1525 to 'converse' from 'inverse' (for compatibility with ZF and some
  1526 literature);
  1527 
  1528 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1529 the well-founded relation;
  1530 
  1531 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1532     Compl A.  The "Compl" syntax remains available as input syntax for this
  1533     release ONLY.
  1534 
  1535 * HOL/Update: new theory of function updates:
  1536     f(a:=b) == %x. if x=a then b else f x
  1537 may also be iterated as in f(a:=b,c:=d,...);
  1538 
  1539 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1540 
  1541 * HOL/List:
  1542   - new function list_update written xs[i:=v] that updates the i-th
  1543     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1544   - new function `upt' written [i..j(] which generates the list
  1545     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1546     bound write [i..j], which is a shorthand for [i..j+1(].
  1547   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1548 
  1549 * HOL/Arith:
  1550   - removed 'pred' (predecessor) function;
  1551   - generalized some theorems about n-1;
  1552   - many new laws about "div" and "mod";
  1553   - new laws about greatest common divisors (see theory ex/Primes);
  1554 
  1555 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1556 instead of "inverse";
  1557 
  1558 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1559   of the multiset ordering;
  1560 
  1561 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1562   (not included by default);
  1563 
  1564 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1565 
  1566 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1567   programs, i.e. different program variables may have different types.
  1568 
  1569 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1570   [previously, this check worked only if the rewrite rule was unconditional]
  1571   Now rew can involve either definitions or equalities (either == or =).
  1572 
  1573 
  1574 *** ZF ***
  1575 
  1576 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1577   only the theorems proved on ZF.ML;
  1578 
  1579 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1580   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1581   disjointness reasoning but breaking a few old proofs.
  1582 
  1583 * ZF/Update: new theory of function updates
  1584     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1585   may also be iterated as in f(a:=b,c:=d,...);
  1586 
  1587 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  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 * case_tac provided for compatibility with HOL
  1594     (like the old excluded_middle_tac, but with subgoals swapped)
  1595 
  1596 
  1597 *** Internal programming interfaces ***
  1598 
  1599 * Pure: several new basic modules made available for general use, see
  1600 also src/Pure/README;
  1601 
  1602 * improved the theory data mechanism to support encapsulation (data
  1603 kind name replaced by private Object.kind, acting as authorization
  1604 key); new type-safe user interface via functor TheoryDataFun; generic
  1605 print_data function becomes basically useless;
  1606 
  1607 * removed global_names compatibility flag -- all theory declarations
  1608 are qualified by default;
  1609 
  1610 * module Pure/Syntax now offers quote / antiquote translation
  1611 functions (useful for Hoare logic etc. with implicit dependencies);
  1612 see HOL/ex/Antiquote for an example use;
  1613 
  1614 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1615 cterm -> thm;
  1616 
  1617 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1618 subgoal;
  1619 
  1620 * Display.print_goals function moved to Locale.print_goals;
  1621 
  1622 * standard print function for goals supports current_goals_markers
  1623 variable for marking begin of proof, end of proof, start of goal; the
  1624 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1625 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1626 for example;
  1627 
  1628 
  1629 
  1630 New in Isabelle98 (January 1998)
  1631 --------------------------------
  1632 
  1633 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1634 
  1635 * changed lexical syntax of terms / types: dots made part of long
  1636 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1637 
  1638 * simpset (and claset) reference variable replaced by functions
  1639 simpset / simpset_ref;
  1640 
  1641 * no longer supports theory aliases (via merge) and non-trivial
  1642 implicit merge of thms' signatures;
  1643 
  1644 * most internal names of constants changed due to qualified names;
  1645 
  1646 * changed Pure/Sequence interface (see Pure/seq.ML);
  1647 
  1648 
  1649 *** General Changes ***
  1650 
  1651 * hierachically structured name spaces (for consts, types, axms, thms
  1652 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1653 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1654 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1655 long_names for fully qualified output names; NOTE: ML programs
  1656 (special tactics, packages etc.) referring to internal names may have
  1657 to be adapted to cope with fully qualified names; in case of severe
  1658 backward campatibility problems try setting 'global_names' at compile
  1659 time to have enrything declared within a flat name space; one may also
  1660 fine tune name declarations in theories via the 'global' and 'local'
  1661 section;
  1662 
  1663 * reimplemented the implicit simpset and claset using the new anytype
  1664 data filed in signatures; references simpset:simpset ref etc. are
  1665 replaced by functions simpset:unit->simpset and
  1666 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1667 to patch your ML files accordingly;
  1668 
  1669 * HTML output now includes theory graph data for display with Java
  1670 applet or isatool browser; data generated automatically via isatool
  1671 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1672 
  1673 * defs may now be conditional; improved rewrite_goals_tac to handle
  1674 conditional equations;
  1675 
  1676 * defs now admits additional type arguments, using TYPE('a) syntax;
  1677 
  1678 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1679 creates a new theory node; implicit merge of thms' signatures is
  1680 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1681 transfer:theory->thm->thm in (rare) cases;
  1682 
  1683 * improved handling of draft signatures / theories; draft thms (and
  1684 ctyps, cterms) are automatically promoted to real ones;
  1685 
  1686 * slightly changed interfaces for oracles: admit many per theory, named
  1687 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1688 
  1689 * print_goals: optional output of const types (set show_consts and
  1690 show_types);
  1691 
  1692 * improved output of warnings (###) and errors (***);
  1693 
  1694 * subgoal_tac displays a warning if the new subgoal has type variables;
  1695 
  1696 * removed old README and Makefiles;
  1697 
  1698 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1699 
  1700 * removed obsolete init_pps and init_database;
  1701 
  1702 * deleted the obsolete tactical STATE, which was declared by
  1703     fun STATE tacfun st = tacfun st st;
  1704 
  1705 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1706 (which abbreviates $HOME);
  1707 
  1708 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1709 use isatool fixseq to adapt your ML programs (this works for fully
  1710 qualified references to the Sequence structure only!);
  1711 
  1712 * use_thy no longer requires writable current directory; it always
  1713 reloads .ML *and* .thy file, if either one is out of date;
  1714 
  1715 
  1716 *** Classical Reasoner ***
  1717 
  1718 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1719 tactics that use classical reasoning to simplify a subgoal without
  1720 splitting it into several subgoals;
  1721 
  1722 * Safe_tac: like safe_tac but uses the default claset;
  1723 
  1724 
  1725 *** Simplifier ***
  1726 
  1727 * added simplification meta rules:
  1728     (asm_)(full_)simplify: simpset -> thm -> thm;
  1729 
  1730 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1731 logics (again);
  1732 
  1733 * added prems argument to simplification procedures;
  1734 
  1735 * HOL, FOL, ZF: added infix function `addsplits':
  1736   instead of `<simpset> setloop (split_tac <thms>)'
  1737   you can simply write `<simpset> addsplits <thms>'
  1738 
  1739 
  1740 *** Syntax ***
  1741 
  1742 * TYPE('a) syntax for type reflection terms;
  1743 
  1744 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1745 
  1746 * pretty printer: changed order of mixfix annotation preference (again!);
  1747 
  1748 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1749 
  1750 
  1751 *** HOL ***
  1752 
  1753 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1754   with `addloop' of the simplifier to faciliate case splitting in premises.
  1755 
  1756 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1757 
  1758 * HOL/Auth: new protocol proofs including some for the Internet
  1759   protocol TLS;
  1760 
  1761 * HOL/Map: new theory of `maps' a la VDM;
  1762 
  1763 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1764 cancelling out common nat summands from =, <, <= (in)equalities, or
  1765 differences; simplification procedures nat_cancel_factor for
  1766 cancelling common factor from =, <, <= (in)equalities over natural
  1767 sums; nat_cancel contains both kinds of procedures, it is installed by
  1768 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1769 
  1770 * HOL/simplifier: terms of the form
  1771   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1772   are rewritten to
  1773   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1774   and those of the form
  1775   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1776   are rewritten to
  1777   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1778 
  1779 * HOL/datatype
  1780   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1781 
  1782   P(t_case f1 ... fn x) =
  1783      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1784         ...
  1785        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1786      )
  1787 
  1788   and a theorem `split_t_case_asm' of the form
  1789 
  1790   P(t_case f1 ... fn x) =
  1791     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1792         ...
  1793        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1794      )
  1795   which can be added to a simpset via `addsplits'. The existing theorems
  1796   expand_list_case and expand_option_case have been renamed to
  1797   split_list_case and split_option_case.
  1798 
  1799 * HOL/Arithmetic:
  1800   - `pred n' is automatically converted to `n-1'.
  1801     Users are strongly encouraged not to use `pred' any longer,
  1802     because it will disappear altogether at some point.
  1803   - Users are strongly encouraged to write "0 < n" rather than
  1804     "n ~= 0". Theorems and proof tools have been modified towards this
  1805     `standard'.
  1806 
  1807 * HOL/Lists:
  1808   the function "set_of_list" has been renamed "set" (and its theorems too);
  1809   the function "nth" now takes its arguments in the reverse order and
  1810   has acquired the infix notation "!" as in "xs!n".
  1811 
  1812 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1813 
  1814 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1815   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1816 
  1817 * HOL/record: extensible records with schematic structural subtyping
  1818 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1819 still lacks various theorems and concrete record syntax;
  1820 
  1821 
  1822 *** HOLCF ***
  1823 
  1824 * removed "axioms" and "generated by" sections;
  1825 
  1826 * replaced "ops" section by extended "consts" section, which is capable of
  1827   handling the continuous function space "->" directly;
  1828 
  1829 * domain package:
  1830   . proves theorems immediately and stores them in the theory,
  1831   . creates hierachical name space,
  1832   . now uses normal mixfix annotations (instead of cinfix...),
  1833   . minor changes to some names and values (for consistency),
  1834   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1835   . separator between mutual domain defs: changed "," to "and",
  1836   . improved handling of sort constraints;  now they have to
  1837     appear on the left-hand side of the equations only;
  1838 
  1839 * fixed LAM <x,y,zs>.b syntax;
  1840 
  1841 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1842 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1843 
  1844 
  1845 *** FOL and ZF ***
  1846 
  1847 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1848   with `addloop' of the simplifier to faciliate case splitting in premises.
  1849 
  1850 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1851 in HOL, they strip ALL and --> from proved theorems;
  1852 
  1853 
  1854 
  1855 New in Isabelle94-8 (May 1997)
  1856 ------------------------------
  1857 
  1858 *** General Changes ***
  1859 
  1860 * new utilities to build / run / maintain Isabelle etc. (in parts
  1861 still somewhat experimental); old Makefiles etc. still functional;
  1862 
  1863 * new 'Isabelle System Manual';
  1864 
  1865 * INSTALL text, together with ./configure and ./build scripts;
  1866 
  1867 * reimplemented type inference for greater efficiency, better error
  1868 messages and clean internal interface;
  1869 
  1870 * prlim command for dealing with lots of subgoals (an easier way of
  1871 setting goals_limit);
  1872 
  1873 
  1874 *** Syntax ***
  1875 
  1876 * supports alternative (named) syntax tables (parser and pretty
  1877 printer); internal interface is provided by add_modesyntax(_i);
  1878 
  1879 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1880 be used in conjunction with the Isabelle symbol font; uses the
  1881 "symbols" syntax table;
  1882 
  1883 * added token_translation interface (may translate name tokens in
  1884 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1885 the current print_mode); IMPORTANT: user print translation functions
  1886 are responsible for marking newly introduced bounds
  1887 (Syntax.mark_boundT);
  1888 
  1889 * token translations for modes "xterm" and "xterm_color" that display
  1890 names in bold, underline etc. or colors (which requires a color
  1891 version of xterm);
  1892 
  1893 * infixes may now be declared with names independent of their syntax;
  1894 
  1895 * added typed_print_translation (like print_translation, but may
  1896 access type of constant);
  1897 
  1898 
  1899 *** Classical Reasoner ***
  1900 
  1901 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1902 some limitations.  Blast_tac...
  1903   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1904   + ignores elimination rules that don't have the correct format
  1905         (the conclusion MUST be a formula variable)
  1906   + ignores types, which can make HOL proofs fail
  1907   + rules must not require higher-order unification, e.g. apply_type in ZF
  1908     [message "Function Var's argument not a bound variable" relates to this]
  1909   + its proof strategy is more general but can actually be slower
  1910 
  1911 * substitution with equality assumptions no longer permutes other
  1912 assumptions;
  1913 
  1914 * minor changes in semantics of addafter (now called addaltern); renamed
  1915 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1916 (and access functions for it);
  1917 
  1918 * improved combination of classical reasoner and simplifier:
  1919   + functions for handling clasimpsets
  1920   + improvement of addss: now the simplifier is called _after_ the
  1921     safe steps.
  1922   + safe variant of addss called addSss: uses safe simplifications
  1923     _during_ the safe steps. It is more complete as it allows multiple
  1924     instantiations of unknowns (e.g. with slow_tac).
  1925 
  1926 *** Simplifier ***
  1927 
  1928 * added interface for simplification procedures (functions that
  1929 produce *proven* rewrite rules on the fly, depending on current
  1930 redex);
  1931 
  1932 * ordering on terms as parameter (used for ordered rewriting);
  1933 
  1934 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1935 
  1936 * the solver is now split into a safe and an unsafe part.
  1937 This should be invisible for the normal user, except that the
  1938 functions setsolver and addsolver have been renamed to setSolver and
  1939 addSolver; added safe_asm_full_simp_tac;
  1940 
  1941 
  1942 *** HOL ***
  1943 
  1944 * a generic induction tactic `induct_tac' which works for all datatypes and
  1945 also for type `nat';
  1946 
  1947 * a generic case distinction tactic `exhaust_tac' which works for all
  1948 datatypes and also for type `nat';
  1949 
  1950 * each datatype comes with a function `size';
  1951 
  1952 * patterns in case expressions allow tuple patterns as arguments to
  1953 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1954 
  1955 * primrec now also works with type nat;
  1956 
  1957 * recdef: a new declaration form, allows general recursive functions to be
  1958 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1959 
  1960 * the constant for negation has been renamed from "not" to "Not" to
  1961 harmonize with FOL, ZF, LK, etc.;
  1962 
  1963 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1964 infinite lists;
  1965 
  1966 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1967 
  1968 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1969 problems in commutative rings, using axiomatic type classes for + and *;
  1970 
  1971 * more examples in HOL/MiniML and HOL/Auth;
  1972 
  1973 * more default rewrite rules for quantifiers, union/intersection;
  1974 
  1975 * a new constant `arbitrary == @x.False';
  1976 
  1977 * HOLCF/IOA replaces old HOL/IOA;
  1978 
  1979 * HOLCF changes: derived all rules and arities
  1980   + axiomatic type classes instead of classes
  1981   + typedef instead of faking type definitions
  1982   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1983   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1984   + eliminated the types void, one, tr
  1985   + use unit lift and bool lift (with translations) instead of one and tr
  1986   + eliminated blift from Lift3.thy (use Def instead of blift)
  1987   all eliminated rules are derived as theorems --> no visible changes ;
  1988 
  1989 
  1990 *** ZF ***
  1991 
  1992 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1993 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1994 as ZF_cs addSIs [equalityI];
  1995 
  1996 
  1997 
  1998 New in Isabelle94-7 (November 96)
  1999 ---------------------------------
  2000 
  2001 * allowing negative levels (as offsets) in prlev and choplev;
  2002 
  2003 * super-linear speedup for large simplifications;
  2004 
  2005 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2006 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2007 FAIL); can suppress it using the command Delsimps (ex_simps @
  2008 all_simps); De Morgan laws are also now included, by default;
  2009 
  2010 * improved printing of ==>  :  ~:
  2011 
  2012 * new object-logic "Sequents" adds linear logic, while replacing LK
  2013 and Modal (thanks to Sara Kalvala);
  2014 
  2015 * HOL/Auth: correctness proofs for authentication protocols;
  2016 
  2017 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2018 examples on HOL/Auth);
  2019 
  2020 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2021 the rewriter and classical reasoner simultaneously;
  2022 
  2023 * function uresult no longer returns theorems in "standard" format;
  2024 regain previous version by: val uresult = standard o uresult;
  2025 
  2026 
  2027 
  2028 New in Isabelle94-6
  2029 -------------------
  2030 
  2031 * oracles -- these establish an interface between Isabelle and trusted
  2032 external reasoners, which may deliver results as theorems;
  2033 
  2034 * proof objects (in particular record all uses of oracles);
  2035 
  2036 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2037 
  2038 * "constdefs" section in theory files;
  2039 
  2040 * "primrec" section (HOL) no longer requires names;
  2041 
  2042 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2043 
  2044 
  2045 
  2046 New in Isabelle94-5
  2047 -------------------
  2048 
  2049 * reduced space requirements;
  2050 
  2051 * automatic HTML generation from theories;
  2052 
  2053 * theory files no longer require "..." (quotes) around most types;
  2054 
  2055 * new examples, including two proofs of the Church-Rosser theorem;
  2056 
  2057 * non-curried (1994) version of HOL is no longer distributed;
  2058 
  2059 
  2060 
  2061 New in Isabelle94-4
  2062 -------------------
  2063 
  2064 * greatly reduced space requirements;
  2065 
  2066 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2067 
  2068 * searchable theorem database (see the section "Retrieving theorems" on
  2069 page 8 of the Reference Manual);
  2070 
  2071 * new examples, including Grabczewski's monumental case study of the
  2072 Axiom of Choice;
  2073 
  2074 * The previous version of HOL renamed to Old_HOL;
  2075 
  2076 * The new version of HOL (previously called CHOL) uses a curried syntax
  2077 for functions.  Application looks like f a b instead of f(a,b);
  2078 
  2079 * Mutually recursive inductive definitions finally work in HOL;
  2080 
  2081 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2082 translates to the operator "split";
  2083 
  2084 
  2085 
  2086 New in Isabelle94-3
  2087 -------------------
  2088 
  2089 * new infix operator, addss, allowing the classical reasoner to
  2090 perform simplification at each step of its search.  Example:
  2091         fast_tac (cs addss ss)
  2092 
  2093 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2094 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2095 look like (a,b) instead of <a,b>;
  2096 
  2097 * PLEASE NOTE: CHOL will eventually replace HOL!
  2098 
  2099 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2100 It translates to the operator "split".  A new theory of integers is available;
  2101 
  2102 * In ZF, integer numerals now denote two's-complement binary integers.
  2103 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2104 
  2105 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2106 of the Axiom of Choice;
  2107 
  2108 
  2109 
  2110 New in Isabelle94-2
  2111 -------------------
  2112 
  2113 * Significantly faster resolution;
  2114 
  2115 * the different sections in a .thy file can now be mixed and repeated
  2116 freely;
  2117 
  2118 * Database of theorems for FOL, HOL and ZF.  New
  2119 commands including qed, qed_goal and bind_thm store theorems in the database.
  2120 
  2121 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2122 a given theory (thms_of), or find out what theory a theorem was proved in
  2123 (theory_of_thm);
  2124 
  2125 * Bugs fixed in the inductive definition and datatype packages;
  2126 
  2127 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2128 and HOL_dup_cs obsolete;
  2129 
  2130 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2131 have been removed;
  2132 
  2133 * Simpler definition of function space in ZF;
  2134 
  2135 * new results about cardinal and ordinal arithmetic in ZF;
  2136 
  2137 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2138 types;
  2139 
  2140 
  2141 $Id$