NEWS
author wenzelm
Thu Dec 27 16:43:56 2001 +0100 (2001-12-27)
changeset 12597 14822e4436bf
parent 12587 3f3d2ffb5df5
child 12608 2df381faa787
permissions -rw-r--r--
HOL/IMP and HOLCF/IMP updated and converted (Gerwin Klein);
     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 theories, 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; several parts
   249 turned into readable document, with proper Isar proof texts and some
   250 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/Induct: new directory for examples of inductive definitions,
   271 including theory Multiset for multiset orderings;
   272 
   273 * ZF: the integer library now covers quotients and remainders, with
   274 many laws relating division to addition, multiplication, etc.;
   275 
   276 
   277 *** General ***
   278 
   279 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   280 variable proof controls level of detail: 0 = no proofs (only oracle
   281 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   282 also ref manual for further ML interfaces;
   283 
   284 * Pure/axclass: removed obsolete ML interface
   285 goal_subclass/goal_arity;
   286 
   287 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   288 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   289 separate tokens, so expressions involving minus need to be spaced
   290 properly;
   291 
   292 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   293 rather than "infixl" or "infixr";
   294 
   295 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   296 sort constraint specifications in type inference; e.g. "x::_::foo"
   297 ensures that the type of "x" is of sort "foo" (but not necessarily a
   298 type variable);
   299 
   300 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   301 control output of nested => (types); the default behavior is
   302 "type_brackets";
   303 
   304 * Pure/syntax: builtin parse translation for "_constify" turns valued
   305 tokens into AST constants;
   306 
   307 * Pure/syntax: prefer later declarations of translations and print
   308 translation functions; potential INCOMPATIBILITY: need to reverse
   309 multiple declarations for same syntax element constant;
   310 
   311 * Provers/classical: renamed addaltern to addafter, addSaltern to
   312 addSafter;
   313 
   314 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   315 as well;
   316 
   317 * system: tested support for MacOS X; should be able to get Isabelle +
   318 Proof General to work in a plain Terminal after installing Poly/ML
   319 (e.g. from the Isabelle distribution area) and GNU bash alone
   320 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   321 support requires further installations, e.g. from
   322 http://fink.sourceforge.net/);
   323 
   324 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   325 
   326 * system: Proof General keywords specification is now part of the
   327 Isabelle distribution (see etc/isar-keywords.el);
   328 
   329 * system: some support for persistent Proof General sessions (refrain
   330 from outdating all loaded theories on startup);
   331 
   332 * system: smart selection of Isabelle process versus Isabelle
   333 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   334 run both "isabelle" and "Isabelle" even if file names are badly
   335 damaged (executable inspects the case of the first letter of its own
   336 name); added separate "isabelle-process" and "isabelle-interface";
   337 
   338 * system: refrain from any attempt at filtering input streams; no
   339 longer support ``8bit'' encoding of old isabelle font, instead proper
   340 iso-latin characters may now be used; the related isatools
   341 "symbolinput" and "nonascii" have disappeared as well;
   342 
   343 * system: removed old "xterm" interface (the print modes "xterm" and
   344 "xterm_color" are still available for direct use in a suitable
   345 terminal);
   346 
   347 
   348 
   349 New in Isabelle99-2 (February 2001)
   350 -----------------------------------
   351 
   352 *** Overview of INCOMPATIBILITIES ***
   353 
   354 * HOL: please note that theories in the Library and elsewhere often use the
   355 new-style (Isar) format; to refer to their theorems in an ML script you must
   356 bind them to ML identifers by e.g.	val thm_name = thm "thm_name";
   357 
   358 * HOL: inductive package no longer splits induction rule aggressively,
   359 but only as far as specified by the introductions given; the old
   360 format may be recovered via ML function complete_split_rule or attribute
   361 'split_rule (complete)';
   362 
   363 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   364 gfp_Tarski to gfp_unfold;
   365 
   366 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   367 
   368 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   369 relation); infix "^^" has been renamed "``"; infix "``" has been
   370 renamed "`"; "univalent" has been renamed "single_valued";
   371 
   372 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   373 operation;
   374 
   375 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   376 
   377 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   378 
   379 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   380 consequence, it is no longer monotonic wrt. the local goal context
   381 (which is now passed through the inductive cases);
   382 
   383 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   384 \<gg> to \<ggreater>;
   385 
   386 
   387 *** Document preparation ***
   388 
   389 * \isabellestyle{NAME} selects version of Isabelle output (currently
   390 available: are "it" for near math-mode best-style output, "sl" for
   391 slanted text style, and "tt" for plain type-writer; if no
   392 \isabellestyle command is given, output is according to slanted
   393 type-writer);
   394 
   395 * support sub/super scripts (for single symbols only), input syntax is
   396 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   397 
   398 * some more standard symbols; see Appendix A of the system manual for
   399 the complete list of symbols defined in isabellesym.sty;
   400 
   401 * improved isabelle style files; more abstract symbol implementation
   402 (should now use \isamath{...} and \isatext{...} in custom symbol
   403 definitions);
   404 
   405 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   406 state; Note that presentation of goal states does not conform to
   407 actual human-readable proof documents.  Please do not include goal
   408 states into document output unless you really know what you are doing!
   409 
   410 * proper indentation of antiquoted output with proportional LaTeX
   411 fonts;
   412 
   413 * no_document ML operator temporarily disables LaTeX document
   414 generation;
   415 
   416 * isatool unsymbolize tunes sources for plain ASCII communication;
   417 
   418 
   419 *** Isar ***
   420 
   421 * Pure: Isar now suffers initial goal statements to contain unbound
   422 schematic variables (this does not conform to actual readable proof
   423 documents, due to unpredictable outcome and non-compositional proof
   424 checking); users who know what they are doing may use schematic goals
   425 for Prolog-style synthesis of proven results;
   426 
   427 * Pure: assumption method (an implicit finishing) now handles actual
   428 rules as well;
   429 
   430 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   431 initial goal, declare "that" only as Pure intro (only for single
   432 steps); the "that" rule assumption may now be involved in implicit
   433 finishing, thus ".." becomes a feasible for trivial obtains;
   434 
   435 * Pure: default proof step now includes 'intro_classes'; thus trivial
   436 instance proofs may be performed by "..";
   437 
   438 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   439 statements as well;
   440 
   441 * Pure: more robust selection of calculational rules;
   442 
   443 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   444 rule (as well as the assumption rule);
   445 
   446 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   447 lemmas, using the graph browser tool;
   448 
   449 * Pure: predict failure of "show" in interactive mode;
   450 
   451 * Pure: 'thms_containing' now takes actual terms as arguments;
   452 
   453 * HOL: improved method 'induct' --- now handles non-atomic goals
   454 (potential INCOMPATIBILITY); tuned error handling;
   455 
   456 * HOL: cases and induct rules now provide explicit hints about the
   457 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   458 any remaining facts are inserted into the goal verbatim;
   459 
   460 * HOL: local contexts (aka cases) may now contain term bindings as
   461 well; the 'cases' and 'induct' methods new provide a ?case binding for
   462 the result to be shown in each case;
   463 
   464 * HOL: added 'recdef_tc' command;
   465 
   466 * isatool convert assists in eliminating legacy ML scripts;
   467 
   468 
   469 *** HOL ***
   470 
   471 * HOL/Library: a collection of generic theories to be used together
   472 with main HOL; the theory loader path already includes this directory
   473 by default; the following existing theories have been moved here:
   474 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   475 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   476 
   477 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   478 modelling and verification task performed in Isabelle/HOL +
   479 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   480 
   481 * HOL/Algebra: special summation operator SUM no longer exists, it has
   482 been replaced by setsum; infix 'assoc' now has priority 50 (like
   483 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   484 'domain', this makes the theory consistent with mathematical
   485 literature;
   486 
   487 * HOL basics: added overloaded operations "inverse" and "divide"
   488 (infix "/"), syntax for generic "abs" operation, generic summation
   489 operator \<Sum>;
   490 
   491 * HOL/typedef: simplified package, provide more useful rules (see also
   492 HOL/subset.thy);
   493 
   494 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   495 now expressed as a proper nested rule (old-style tactic scripts may
   496 require atomize_strip_tac to cope with non-atomic premises);
   497 
   498 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   499 to "split_conv" (old name still available for compatibility);
   500 
   501 * HOL: improved concrete syntax for strings (e.g. allows translation
   502 rules with string literals);
   503 
   504 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   505  and Fleuriot's mechanization of analysis, including the transcendental
   506  functions for the reals;
   507 
   508 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   509 
   510 
   511 *** CTT ***
   512 
   513 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   514 "lam" is displayed as TWO lambda-symbols
   515 
   516 * CTT: theory Main now available, containing everything (that is, Bool
   517 and Arith);
   518 
   519 
   520 *** General ***
   521 
   522 * Pure: the Simplifier has been implemented properly as a derived rule
   523 outside of the actual kernel (at last!); the overall performance
   524 penalty in practical applications is about 50%, while reliability of
   525 the Isabelle inference kernel has been greatly improved;
   526 
   527 * print modes "brackets" and "no_brackets" control output of nested =>
   528 (types) and ==> (props); the default behaviour is "brackets";
   529 
   530 * Provers: fast_tac (and friends) now handle actual object-logic rules
   531 as assumptions as well;
   532 
   533 * system: support Poly/ML 4.0;
   534 
   535 * system: isatool install handles KDE version 1 or 2;
   536 
   537 
   538 
   539 New in Isabelle99-1 (October 2000)
   540 ----------------------------------
   541 
   542 *** Overview of INCOMPATIBILITIES ***
   543 
   544 * HOL: simplification of natural numbers is much changed; to partly
   545 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   546 issue the following ML commands:
   547 
   548   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   549   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   550 
   551 * HOL: simplification no longer dives into case-expressions; this is
   552 controlled by "t.weak_case_cong" for each datatype t;
   553 
   554 * HOL: nat_less_induct renamed to less_induct;
   555 
   556 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   557 fixsome to patch .thy and .ML sources automatically;
   558 
   559   select_equality  -> some_equality
   560   select_eq_Ex     -> some_eq_ex
   561   selectI2EX       -> someI2_ex
   562   selectI2         -> someI2
   563   selectI          -> someI
   564   select1_equality -> some1_equality
   565   Eps_sym_eq       -> some_sym_eq_trivial
   566   Eps_eq           -> some_eq_trivial
   567 
   568 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   569 
   570 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   571 instead);
   572 
   573 * HOL: the recursion equations generated by 'recdef' are now called
   574 f.simps instead of f.rules;
   575 
   576 * HOL: qed_spec_mp now also handles bounded ALL as well;
   577 
   578 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   579 sometimes be needed;
   580 
   581 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   582 
   583 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   584 
   585 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   586 product is now "<*>" instead of "Times"; the lexicographic product is
   587 now "<*lex*>" instead of "**";
   588 
   589 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   590 of main HOL, but was unused); better use HOL's datatype package;
   591 
   592 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   593 the old syntax may be recovered as follows:
   594 
   595   syntax (symbols)
   596     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   597       (infixl "\\<oplus>" 100)
   598 
   599 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   600 
   601 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   602 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   603 internally;
   604 
   605 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   606 changed from A/r to A//r;
   607 
   608 * ZF: new treatment of arithmetic (nat & int) may break some old
   609 proofs;
   610 
   611 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   612 rulify -> rule_format, elimify -> elim_format, ...);
   613 
   614 * Isar/Provers: intro/elim/dest attributes changed; renamed
   615 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   616 should have to change intro!! to intro? only); replaced "delrule" by
   617 "rule del";
   618 
   619 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   620 
   621 * Provers: strengthened force_tac by using new first_best_tac;
   622 
   623 * LaTeX document preparation: several changes of isabelle.sty (see
   624 lib/texinputs);
   625 
   626 
   627 *** Document preparation ***
   628 
   629 * formal comments (text blocks etc.) in new-style theories may now
   630 contain antiquotations of thm/prop/term/typ/text to be presented
   631 according to latex print mode; concrete syntax is like this:
   632 @{term[show_types] "f(x) = a + x"};
   633 
   634 * isatool mkdir provides easy setup of Isabelle session directories,
   635 including proper document sources;
   636 
   637 * generated LaTeX sources are now deleted after successful run
   638 (isatool document -c); may retain a copy somewhere else via -D option
   639 of isatool usedir;
   640 
   641 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   642 style files, achieving self-contained LaTeX sources and simplifying
   643 LaTeX debugging;
   644 
   645 * old-style theories now produce (crude) LaTeX output as well;
   646 
   647 * browser info session directories are now self-contained (may be put
   648 on WWW server seperately); improved graphs of nested sessions; removed
   649 graph for 'all sessions';
   650 
   651 * several improvements in isabelle style files; \isabellestyle{it}
   652 produces fake math mode output; \isamarkupheader is now \section by
   653 default; see lib/texinputs/isabelle.sty etc.;
   654 
   655 
   656 *** Isar ***
   657 
   658 * Isar/Pure: local results and corresponding term bindings are now
   659 subject to Hindley-Milner polymorphism (similar to ML); this
   660 accommodates incremental type-inference very nicely;
   661 
   662 * Isar/Pure: new derived language element 'obtain' supports
   663 generalized existence reasoning;
   664 
   665 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   666 support accumulation of results, without applying any rules yet;
   667 useful to collect intermediate results without explicit name
   668 references, and for use with transitivity rules with more than 2
   669 premises;
   670 
   671 * Isar/Pure: scalable support for case-analysis type proofs: new
   672 'case' language element refers to local contexts symbolically, as
   673 produced by certain proof methods; internally, case names are attached
   674 to theorems as "tags";
   675 
   676 * Isar/Pure: theory command 'hide' removes declarations from
   677 class/type/const name spaces;
   678 
   679 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   680 indicate potential overloading;
   681 
   682 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   683 
   684 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   685 "{a,b,c}" instead of {a,b,c};
   686 
   687 * Isar/Pure now provides its own version of intro/elim/dest
   688 attributes; useful for building new logics, but beware of confusion
   689 with the version in Provers/classical;
   690 
   691 * Isar/Pure: the local context of (non-atomic) goals is provided via
   692 case name 'antecedent';
   693 
   694 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   695 to the current context is now done automatically);
   696 
   697 * Isar/Pure: theory command 'method_setup' provides a simple interface
   698 for definining proof methods in ML;
   699 
   700 * Isar/Provers: intro/elim/dest attributes changed; renamed
   701 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   702 most cases, one should have to change intro!! to intro? only);
   703 replaced "delrule" by "rule del";
   704 
   705 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   706 'symmetric' attribute (the latter supercedes [RS sym]);
   707 
   708 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   709 method modifier); 'simp' method: 'only:' modifier removes loopers as
   710 well (including splits);
   711 
   712 * Isar/Provers: Simplifier and Classical methods now support all kind
   713 of modifiers used in the past, including 'cong', 'iff', etc.
   714 
   715 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   716 of Simplifier and Classical reasoner);
   717 
   718 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   719 now support named cases; major packages (inductive, datatype, primrec,
   720 recdef) support case names and properly name parameters;
   721 
   722 * Isar/HOL: new transitivity rules for substitution in inequalities --
   723 monotonicity conditions are extracted to be proven at end of
   724 calculations;
   725 
   726 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   727 method anyway;
   728 
   729 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   730 split_if split_if_asm; datatype package provides theorems foo.splits =
   731 foo.split foo.split_asm for each datatype;
   732 
   733 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   734 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   735 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   736 use "(cases (simplified))" method in proper proof texts);
   737 
   738 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   739 
   740 * Isar: names of theorems etc. may be natural numbers as well;
   741 
   742 * Isar: 'pr' command: optional arguments for goals_limit and
   743 ProofContext.prems_limit; no longer prints theory contexts, but only
   744 proof states;
   745 
   746 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   747 additional print modes to be specified; e.g. "pr(latex)" will print
   748 proof state according to the Isabelle LaTeX style;
   749 
   750 * Isar: improved support for emulating tactic scripts, including proof
   751 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   752 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   753 (for HOL datatypes);
   754 
   755 * Isar: simplified (more robust) goal selection of proof methods: 1st
   756 goal, all goals, or explicit goal specifier (tactic emulation); thus
   757 'proof method scripts' have to be in depth-first order;
   758 
   759 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   760 
   761 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   762 should instead use individual commands for printing items
   763 (print_commands, print_methods etc.);
   764 
   765 * Isar: added 'nothing' --- the empty list of theorems;
   766 
   767 
   768 *** HOL ***
   769 
   770 * HOL/MicroJava: formalization of a fragment of Java, together with a
   771 corresponding virtual machine and a specification of its bytecode
   772 verifier and a lightweight bytecode verifier, including proofs of
   773 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   774 Cornelia Pusch (see also the homepage of project Bali at
   775 http://isabelle.in.tum.de/Bali/);
   776 
   777 * HOL/Algebra: new theory of rings and univariate polynomials, by
   778 Clemens Ballarin;
   779 
   780 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   781 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   782 Rasmussen;
   783 
   784 * HOL/Lattice: fundamental concepts of lattice theory and order
   785 structures, including duals, properties of bounds versus algebraic
   786 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   787 Theorem for complete lattices etc.; may also serve as a demonstration
   788 for abstract algebraic reasoning using axiomatic type classes, and
   789 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   790 
   791 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   792 von Oheimb;
   793 
   794 * HOL/IMPP: extension of IMP with local variables and mutually
   795 recursive procedures, by David von Oheimb;
   796 
   797 * HOL/Lambda: converted into new-style theory and document;
   798 
   799 * HOL/ex/Multiquote: example of multiple nested quotations and
   800 anti-quotations -- basically a generalized version of de-Bruijn
   801 representation; very useful in avoiding lifting of operations;
   802 
   803 * HOL/record: added general record equality rule to simpset; fixed
   804 select-update simplification procedure to handle extended records as
   805 well; admit "r" as field name;
   806 
   807 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   808 other numeric types and also as the identity of groups, rings, etc.;
   809 
   810 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   811 Types nat and int belong to this axclass;
   812 
   813 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   814    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   815    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   816   two terms #m*u and #n*u are replaced by #(m+n)*u
   817     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   818   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   819     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   820 
   821 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   822 powerful prover for predicate logic but knows nothing of clasets; see
   823 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   824 
   825 * HOL: new version of "case_tac" subsumes both boolean case split and
   826 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   827 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   828 
   829 * HOL: simplification no longer dives into case-expressions: only the
   830 selector expression is simplified, but not the remaining arms; to
   831 enable full simplification of case-expressions for datatype t, you may
   832 remove t.weak_case_cong from the simpset, either globally (Delcongs
   833 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   834 
   835 * HOL/recdef: the recursion equations generated by 'recdef' for
   836 function 'f' are now called f.simps instead of f.rules; if all
   837 termination conditions are proved automatically, these simplification
   838 rules are added to the simpset, as in primrec; rules may be named
   839 individually as well, resulting in a separate list of theorems for
   840 each equation;
   841 
   842 * HOL/While is a new theory that provides a while-combinator. It
   843 permits the definition of tail-recursive functions without the
   844 provision of a termination measure. The latter is necessary once the
   845 invariant proof rule for while is applied.
   846 
   847 * HOL: new (overloaded) notation for the set of elements below/above
   848 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   849 
   850 * HOL: theorems impI, allI, ballI bound as "strip";
   851 
   852 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   853 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   854 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   855 
   856 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   857 
   858 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   859 main HOL, but was unused);
   860 
   861 * HOL: fewer consts declared as global (e.g. have to refer to
   862 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   863 
   864 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   865 in case of overlap with user translations (e.g. judgements over
   866 tuples); (note that the underlying logical represenation is still
   867 bogus);
   868 
   869 
   870 *** ZF ***
   871 
   872 * ZF: simplification automatically cancels common terms in arithmetic
   873 expressions over nat and int;
   874 
   875 * ZF: new treatment of nat to minimize type-checking: all operators
   876 coerce their operands to a natural number using the function natify,
   877 making the algebraic laws unconditional;
   878 
   879 * ZF: as above, for int: operators coerce their operands to an integer
   880 using the function intify;
   881 
   882 * ZF: the integer library now contains many of the usual laws for the
   883 orderings, including $<=, and monotonicity laws for $+ and $*;
   884 
   885 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   886 simplification;
   887 
   888 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   889 to the simplifier and classical reasoner simultaneously;
   890 
   891 
   892 *** General ***
   893 
   894 * Provers: blast_tac now handles actual object-logic rules as
   895 assumptions; note that auto_tac uses blast_tac internally as well;
   896 
   897 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   898 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   899 
   900 * Provers: delrules now handles destruct rules as well (no longer need
   901 explicit make_elim);
   902 
   903 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   904   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   905 use instead the strong form,
   906   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   907 in HOL, FOL and ZF the function cla_make_elim will create such rules
   908 from destruct-rules;
   909 
   910 * Provers: Simplifier.easy_setup provides a fast path to basic
   911 Simplifier setup for new object-logics;
   912 
   913 * Pure: AST translation rules no longer require constant head on LHS;
   914 
   915 * Pure: improved name spaces: ambiguous output is qualified; support
   916 for hiding of names;
   917 
   918 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   919 XSYMBOL_HOME; no longer need to do manual configuration in most
   920 situations;
   921 
   922 * system: compression of ML heaps images may now be controlled via -c
   923 option of isabelle and isatool usedir (currently only observed by
   924 Poly/ML);
   925 
   926 * system: isatool installfonts may handle X-Symbol fonts as well (very
   927 useful for remote X11);
   928 
   929 * system: provide TAGS file for Isabelle sources;
   930 
   931 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   932 order;
   933 
   934 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   935 timing flag supersedes proof_timing and Toplevel.trace;
   936 
   937 * ML: new combinators |>> and |>>> for incremental transformations
   938 with secondary results (e.g. certain theory extensions):
   939 
   940 * ML: PureThy.add_defs gets additional argument to indicate potential
   941 overloading (usually false);
   942 
   943 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   944 results;
   945 
   946 
   947 
   948 New in Isabelle99 (October 1999)
   949 --------------------------------
   950 
   951 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   952 
   953 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   954 are no longer simplified.  (This allows the simplifier to unfold recursive
   955 functional programs.)  To restore the old behaviour, declare
   956 
   957     Delcongs [if_weak_cong];
   958 
   959 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   960 complement;
   961 
   962 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   963 
   964 * HOL/datatype: mutual_induct_tac no longer exists --
   965   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   966 
   967 * HOL/typedef: fixed type inference for representing set; type
   968 arguments now have to occur explicitly on the rhs as type constraints;
   969 
   970 * ZF: The con_defs part of an inductive definition may no longer refer
   971 to constants declared in the same theory;
   972 
   973 * HOL, ZF: the function mk_cases, generated by the inductive
   974 definition package, has lost an argument.  To simplify its result, it
   975 uses the default simpset instead of a supplied list of theorems.
   976 
   977 * HOL/List: the constructors of type list are now Nil and Cons;
   978 
   979 * Simplifier: the type of the infix ML functions
   980         setSSolver addSSolver setSolver addSolver
   981 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   982 for packaging solvers. A solver is created via
   983         mk_solver: string -> (thm list -> int -> tactic) -> solver
   984 where the string argument is only a comment.
   985 
   986 
   987 *** Proof tools ***
   988 
   989 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   990 decision procedure for linear arithmetic. Currently it is used for
   991 types `nat', `int', and `real' in HOL (see below); it can, should and
   992 will be instantiated for other types and logics as well.
   993 
   994 * The simplifier now accepts rewrite rules with flexible heads, eg
   995      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   996   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   997   matching.
   998 
   999 
  1000 *** General ***
  1001 
  1002 * New Isabelle/Isar subsystem provides an alternative to traditional
  1003 tactical theorem proving; together with the ProofGeneral/isar user
  1004 interface it offers an interactive environment for developing human
  1005 readable proof documents (Isar == Intelligible semi-automated
  1006 reasoning); for further information see isatool doc isar-ref,
  1007 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1008 
  1009 * improved and simplified presentation of theories: better HTML markup
  1010 (including colors), graph views in several sizes; isatool usedir now
  1011 provides a proper interface for user theories (via -P option); actual
  1012 document preparation based on (PDF)LaTeX is available as well (for
  1013 new-style theories only); see isatool doc system for more information;
  1014 
  1015 * native support for Proof General, both for classic Isabelle and
  1016 Isabelle/Isar;
  1017 
  1018 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1019 using the graph browser tool;
  1020 
  1021 * Isabelle manuals now also available as PDF;
  1022 
  1023 * theory loader rewritten from scratch (may not be fully
  1024 bug-compatible); old loadpath variable has been replaced by show_path,
  1025 add_path, del_path, reset_path functions; new operations such as
  1026 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1027 isatool doc ref);
  1028 
  1029 * improved isatool install: option -k creates KDE application icon,
  1030 option -p DIR installs standalone binaries;
  1031 
  1032 * added ML_PLATFORM setting (useful for cross-platform installations);
  1033 more robust handling of platform specific ML images for SML/NJ;
  1034 
  1035 * the settings environment is now statically scoped, i.e. it is never
  1036 created again in sub-processes invoked from isabelle, isatool, or
  1037 Isabelle;
  1038 
  1039 * path element specification '~~' refers to '$ISABELLE_HOME';
  1040 
  1041 * in locales, the "assumes" and "defines" parts may be omitted if
  1042 empty;
  1043 
  1044 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1045 long arrows);
  1046 
  1047 * new print_mode "HTML";
  1048 
  1049 * new flag show_tags controls display of tags of theorems (which are
  1050 basically just comments that may be attached by some tools);
  1051 
  1052 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1053 mode and goal output format:
  1054 
  1055 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1056 244c244
  1057 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1058 ---
  1059 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1060 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1061 181c181
  1062 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1063 ---
  1064 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1065 
  1066 * function bind_thms stores lists of theorems (cf. bind_thm);
  1067 
  1068 * new shorthand tactics ftac, eatac, datac, fatac;
  1069 
  1070 * qed (and friends) now accept "" as result name; in that case the
  1071 theorem is not stored, but proper checks and presentation of the
  1072 result still apply;
  1073 
  1074 * theorem database now also indexes constants "Trueprop", "all",
  1075 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1076 
  1077 
  1078 *** HOL ***
  1079 
  1080 ** HOL arithmetic **
  1081 
  1082 * There are now decision procedures for linear arithmetic over nat and
  1083 int:
  1084 
  1085 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1086 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1087 are treated as atomic; subformulae not involving type `nat' or `int'
  1088 are ignored; quantified subformulae are ignored unless they are
  1089 positive universal or negative existential. The tactic has to be
  1090 invoked by hand and can be a little bit slow. In particular, the
  1091 running time is exponential in the number of occurrences of `min' and
  1092 `max', and `-' on `nat'.
  1093 
  1094 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1095 (negated) (in)equalities among the premises and the conclusion into
  1096 account (i.e. no compound formulae) and does not know about `min' and
  1097 `max', and `-' on `nat'. It is fast and is used automatically by the
  1098 simplifier.
  1099 
  1100 NB: At the moment, these decision procedures do not cope with mixed
  1101 nat/int formulae where the two parts interact, such as `m < n ==>
  1102 int(m) < int(n)'.
  1103 
  1104 * HOL/Numeral provides a generic theory of numerals (encoded
  1105 efficiently as bit strings); setup for types nat/int/real is in place;
  1106 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1107 int, existing theories and proof scripts may require a few additional
  1108 type constraints;
  1109 
  1110 * integer division and remainder can now be performed on constant
  1111 arguments;
  1112 
  1113 * many properties of integer multiplication, division and remainder
  1114 are now available;
  1115 
  1116 * An interface to the Stanford Validity Checker (SVC) is available through the
  1117 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1118 are proved automatically.  SVC must be installed separately, and its results
  1119 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1120 invocation of the underlying oracle).  For SVC see
  1121   http://verify.stanford.edu/SVC
  1122 
  1123 * IsaMakefile: the HOL-Real target now builds an actual image;
  1124 
  1125 
  1126 ** HOL misc **
  1127 
  1128 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1129 (in Isabelle/Isar) -- by Gertrud Bauer;
  1130 
  1131 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1132 analysis for assembly languages with subtypes;
  1133 
  1134 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1135 -- avoids syntactic ambiguities and treats state, transition, and
  1136 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1137 changed syntax and (many) tactics;
  1138 
  1139 * HOL/inductive: Now also handles more general introduction rules such
  1140   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1141   theorems are now maintained within the theory (maintained via the
  1142   "mono" attribute);
  1143 
  1144 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1145   (using function types) such as
  1146 
  1147   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1148 
  1149 * HOL/record: record_simproc (part of the default simpset) takes care
  1150 of selectors applied to updated records; record_split_tac is no longer
  1151 part of the default claset; update_defs may now be removed from the
  1152 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1153 
  1154   claset_ref () := claset() addSWrapper record_split_wrapper;
  1155   Delsimprocs [record_simproc]
  1156 
  1157 * HOL/typedef: fixed type inference for representing set; type
  1158 arguments now have to occur explicitly on the rhs as type constraints;
  1159 
  1160 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1161 names rather than an ML expression;
  1162 
  1163 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1164 supplied later.  Program schemes can be defined, such as
  1165     "While B C s = (if B s then While B C (C s) else s)"
  1166 where the well-founded relation can be chosen after B and C have been given.
  1167 
  1168 * HOL/List: the constructors of type list are now Nil and Cons;
  1169 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1170 course, ML tools referring to List.list.op # etc. have to be adapted;
  1171 
  1172 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1173 disabled by default; run isabelle with option -m HOL to get back to
  1174 the original Gordon/HOL-style output;
  1175 
  1176 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1177 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1178 
  1179 * HOL basic syntax simplified (more orthogonal): all variants of
  1180 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1181 Eps operator is provided as well: "SOME x. P[x]";
  1182 
  1183 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1184 
  1185 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1186 thus available for user theories;
  1187 
  1188 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1189 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1190 time;
  1191 
  1192 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1193 several times and then mp;
  1194 
  1195 
  1196 *** LK ***
  1197 
  1198 * the notation <<...>> is now available as a notation for sequences of
  1199 formulas;
  1200 
  1201 * the simplifier is now installed
  1202 
  1203 * the axiom system has been generalized (thanks to Soren Heilmann)
  1204 
  1205 * the classical reasoner now has a default rule database
  1206 
  1207 
  1208 *** ZF ***
  1209 
  1210 * new primrec section allows primitive recursive functions to be given
  1211 directly (as in HOL) over datatypes and the natural numbers;
  1212 
  1213 * new tactics induct_tac and exhaust_tac for induction (or case
  1214 analysis) over datatypes and the natural numbers;
  1215 
  1216 * the datatype declaration of type T now defines the recursor T_rec;
  1217 
  1218 * simplification automatically does freeness reasoning for datatype
  1219 constructors;
  1220 
  1221 * automatic type-inference, with AddTCs command to insert new
  1222 type-checking rules;
  1223 
  1224 * datatype introduction rules are now added as Safe Introduction rules
  1225 to the claset;
  1226 
  1227 * the syntax "if P then x else y" is now available in addition to
  1228 if(P,x,y);
  1229 
  1230 
  1231 *** Internal programming interfaces ***
  1232 
  1233 * tuned simplifier trace output; new flag debug_simp;
  1234 
  1235 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1236 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1237 
  1238 * AxClass.axclass_tac lost the theory argument;
  1239 
  1240 * tuned current_goals_markers semantics: begin / end goal avoids
  1241 printing empty lines;
  1242 
  1243 * removed prs and prs_fn hook, which was broken because it did not
  1244 include \n in its semantics, forcing writeln to add one
  1245 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1246 string -> unit if you really want to output text without newline;
  1247 
  1248 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1249 plain output, interface builders may have to enable 'isabelle_font'
  1250 mode to get Isabelle font glyphs as before;
  1251 
  1252 * refined token_translation interface; INCOMPATIBILITY: output length
  1253 now of type real instead of int;
  1254 
  1255 * theory loader actions may be traced via new ThyInfo.add_hook
  1256 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1257 your own database of information attached to *whole* theories -- as
  1258 opposed to intra-theory data slots offered via TheoryDataFun;
  1259 
  1260 * proper handling of dangling sort hypotheses (at last!);
  1261 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1262 extra sort hypotheses that can be witnessed from the type signature;
  1263 the force_strip_shyps flag is gone, any remaining shyps are simply
  1264 left in the theorem (with a warning issued by strip_shyps_warning);
  1265 
  1266 
  1267 
  1268 New in Isabelle98-1 (October 1998)
  1269 ----------------------------------
  1270 
  1271 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1272 
  1273 * several changes of automated proof tools;
  1274 
  1275 * HOL: major changes to the inductive and datatype packages, including
  1276 some minor incompatibilities of theory syntax;
  1277 
  1278 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1279 called `inj_on';
  1280 
  1281 * HOL: removed duplicate thms in Arith:
  1282   less_imp_add_less  should be replaced by  trans_less_add1
  1283   le_imp_add_le      should be replaced by  trans_le_add1
  1284 
  1285 * HOL: unary minus is now overloaded (new type constraints may be
  1286 required);
  1287 
  1288 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1289 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1290 now taken as an integer constant.
  1291 
  1292 * Pure: ML function 'theory_of' renamed to 'theory';
  1293 
  1294 
  1295 *** Proof tools ***
  1296 
  1297 * Simplifier:
  1298   1. Asm_full_simp_tac is now more aggressive.
  1299      1. It will sometimes reorient premises if that increases their power to
  1300         simplify.
  1301      2. It does no longer proceed strictly from left to right but may also
  1302         rotate premises to achieve further simplification.
  1303      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1304      old Asm_full_simp_tac in that it does not rotate premises.
  1305   2. The simplifier now knows a little bit about nat-arithmetic.
  1306 
  1307 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1308 allows for selected deletion of wrappers, by introduction of names for
  1309 wrapper functionals.  This implies that addbefore, addSbefore,
  1310 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1311 and that adding two tactics with the same name overwrites the first
  1312 one (emitting a warning).
  1313   type wrapper = (int -> tactic) -> (int -> tactic)
  1314   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1315   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1316   delWrapper, delSWrapper: claset *  string            -> claset
  1317   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1318 
  1319 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1320 semantics; addbefore now affects only the unsafe part of step_tac
  1321 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1322 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1323 by Force_tac;
  1324 
  1325 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1326 compWrapper; added safe wrapper (and access functions for it);
  1327 
  1328 * HOL/split_all_tac is now much faster and fails if there is nothing
  1329 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1330 and the names of the automatically generated variables have changed.
  1331 split_all_tac has moved within claset() from unsafe wrappers to safe
  1332 wrappers, which means that !!-bound variables are split much more
  1333 aggressively, and safe_tac and clarify_tac now split such variables.
  1334 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1335 Note: the same holds for record_split_tac, which does the job of
  1336 split_all_tac for record fields.
  1337 
  1338 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1339 permanently to the default simpset using Addsplits just like
  1340 Addsimps. They can be removed via Delsplits just like
  1341 Delsimps. Lower-case versions are also available.
  1342 
  1343 * HOL/Simplifier: The rule split_if is now part of the default
  1344 simpset. This means that the simplifier will eliminate all occurrences
  1345 of if-then-else in the conclusion of a goal. To prevent this, you can
  1346 either remove split_if completely from the default simpset by
  1347 `Delsplits [split_if]' or remove it in a specific call of the
  1348 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1349 other case splitting rules to/from the default simpset: every datatype
  1350 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1351 t is the name of the datatype).
  1352 
  1353 * Classical reasoner / Simplifier combination: new force_tac (and
  1354 derivatives Force_tac, force) combines rewriting and classical
  1355 reasoning (and whatever other tools) similarly to auto_tac, but is
  1356 aimed to solve the given subgoal completely.
  1357 
  1358 
  1359 *** General ***
  1360 
  1361 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1362 and `goalw': the theory is no longer needed as an explicit argument -
  1363 the current theory context is used; assumptions are no longer returned
  1364 at the ML-level unless one of them starts with ==> or !!; it is
  1365 recommended to convert to these new commands using isatool fixgoal
  1366 (backup your sources first!);
  1367 
  1368 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1369 the current theory context, and 'theory' to lookup stored theories;
  1370 
  1371 * new theory section 'locale' for declaring constants, assumptions and
  1372 definitions that have local scope;
  1373 
  1374 * new theory section 'nonterminals' for purely syntactic types;
  1375 
  1376 * new theory section 'setup' for generic ML setup functions
  1377 (e.g. package initialization);
  1378 
  1379 * the distribution now includes Isabelle icons: see
  1380 lib/logo/isabelle-{small,tiny}.xpm;
  1381 
  1382 * isatool install - install binaries with absolute references to
  1383 ISABELLE_HOME/bin;
  1384 
  1385 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1386 
  1387 * print mode 'emacs' reserved for Isamode;
  1388 
  1389 * support multiple print (ast) translations per constant name;
  1390 
  1391 * theorems involving oracles are now printed with a suffixed [!];
  1392 
  1393 
  1394 *** HOL ***
  1395 
  1396 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1397 
  1398 * HOL/inductive package reorganized and improved: now supports mutual
  1399 definitions such as
  1400 
  1401   inductive EVEN ODD
  1402     intrs
  1403       null "0 : EVEN"
  1404       oddI "n : EVEN ==> Suc n : ODD"
  1405       evenI "n : ODD ==> Suc n : EVEN"
  1406 
  1407 new theorem list "elims" contains an elimination rule for each of the
  1408 recursive sets; inductive definitions now handle disjunctive premises
  1409 correctly (also ZF);
  1410 
  1411 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1412 "mutual_induct" no longer exists - the induction rule is always
  1413 contained in "induct";
  1414 
  1415 
  1416 * HOL/datatype package re-implemented and greatly improved: now
  1417 supports mutually recursive datatypes such as
  1418 
  1419   datatype
  1420     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1421             | SUM ('a aexp) ('a aexp)
  1422             | DIFF ('a aexp) ('a aexp)
  1423             | NUM 'a
  1424   and
  1425     'a bexp = LESS ('a aexp) ('a aexp)
  1426             | AND ('a bexp) ('a bexp)
  1427             | OR ('a bexp) ('a bexp)
  1428 
  1429 as well as indirectly recursive datatypes such as
  1430 
  1431   datatype
  1432     ('a, 'b) term = Var 'a
  1433                   | App 'b ((('a, 'b) term) list)
  1434 
  1435 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1436 induction on mutually / indirectly recursive datatypes.
  1437 
  1438 Primrec equations are now stored in theory and can be accessed via
  1439 <function_name>.simps.
  1440 
  1441 INCOMPATIBILITIES:
  1442 
  1443   - Theories using datatypes must now have theory Datatype as an
  1444     ancestor.
  1445   - The specific <typename>.induct_tac no longer exists - use the
  1446     generic induct_tac instead.
  1447   - natE has been renamed to nat.exhaust - use exhaust_tac
  1448     instead of res_inst_tac ... natE. Note that the variable
  1449     names in nat.exhaust differ from the names in natE, this
  1450     may cause some "fragile" proofs to fail.
  1451   - The theorems split_<typename>_case and split_<typename>_case_asm
  1452     have been renamed to <typename>.split and <typename>.split_asm.
  1453   - Since default sorts of type variables are now handled correctly,
  1454     some datatype definitions may have to be annotated with explicit
  1455     sort constraints.
  1456   - Primrec definitions no longer require function name and type
  1457     of recursive argument.
  1458 
  1459 Consider using isatool fixdatatype to adapt your theories and proof
  1460 scripts to the new package (backup your sources first!).
  1461 
  1462 
  1463 * HOL/record package: considerably improved implementation; now
  1464 includes concrete syntax for record types, terms, updates; theorems
  1465 for surjective pairing and splitting !!-bound record variables; proof
  1466 support is as follows:
  1467 
  1468   1) standard conversions (selectors or updates applied to record
  1469 constructor terms) are part of the standard simpset;
  1470 
  1471   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1472 made part of standard simpset and claset via addIffs;
  1473 
  1474   3) a tactic for record field splitting (record_split_tac) is part of
  1475 the standard claset (addSWrapper);
  1476 
  1477 To get a better idea about these rules you may retrieve them via
  1478 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1479 the name of your record type.
  1480 
  1481 The split tactic 3) conceptually simplifies by the following rule:
  1482 
  1483   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1484 
  1485 Thus any record variable that is bound by meta-all will automatically
  1486 blow up into some record constructor term, consequently the
  1487 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1488 solve record problems automatically.
  1489 
  1490 
  1491 * reorganized the main HOL image: HOL/Integ and String loaded by
  1492 default; theory Main includes everything;
  1493 
  1494 * automatic simplification of integer sums and comparisons, using cancellation;
  1495 
  1496 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1497 
  1498 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1499 
  1500 * many new identities for unions, intersections, set difference, etc.;
  1501 
  1502 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1503 called split_if, split_split, split_sum_case and split_nat_case (to go
  1504 with add/delsplits);
  1505 
  1506 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1507 (?x::unit) = (); this is made part of the default simpset, which COULD
  1508 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1509 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1510 unit_abs_eta_conv is added in order to counter the effect of
  1511 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1512 %u.f();
  1513 
  1514 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1515 makes more sense);
  1516 
  1517 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1518   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1519   disjointness reasoning but breaking a few old proofs.
  1520 
  1521 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1522 to 'converse' from 'inverse' (for compatibility with ZF and some
  1523 literature);
  1524 
  1525 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1526 the well-founded relation;
  1527 
  1528 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1529     Compl A.  The "Compl" syntax remains available as input syntax for this
  1530     release ONLY.
  1531 
  1532 * HOL/Update: new theory of function updates:
  1533     f(a:=b) == %x. if x=a then b else f x
  1534 may also be iterated as in f(a:=b,c:=d,...);
  1535 
  1536 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1537 
  1538 * HOL/List:
  1539   - new function list_update written xs[i:=v] that updates the i-th
  1540     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1541   - new function `upt' written [i..j(] which generates the list
  1542     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1543     bound write [i..j], which is a shorthand for [i..j+1(].
  1544   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1545 
  1546 * HOL/Arith:
  1547   - removed 'pred' (predecessor) function;
  1548   - generalized some theorems about n-1;
  1549   - many new laws about "div" and "mod";
  1550   - new laws about greatest common divisors (see theory ex/Primes);
  1551 
  1552 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1553 instead of "inverse";
  1554 
  1555 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1556   of the multiset ordering;
  1557 
  1558 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1559   (not included by default);
  1560 
  1561 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1562 
  1563 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1564   programs, i.e. different program variables may have different types.
  1565 
  1566 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1567   [previously, this check worked only if the rewrite rule was unconditional]
  1568   Now rew can involve either definitions or equalities (either == or =).
  1569 
  1570 
  1571 *** ZF ***
  1572 
  1573 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1574   only the theorems proved on ZF.ML;
  1575 
  1576 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1577   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1578   disjointness reasoning but breaking a few old proofs.
  1579 
  1580 * ZF/Update: new theory of function updates
  1581     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1582   may also be iterated as in f(a:=b,c:=d,...);
  1583 
  1584 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1585 
  1586 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1587   [previously, this check worked only if the rewrite rule was unconditional]
  1588   Now rew can involve either definitions or equalities (either == or =).
  1589 
  1590 * case_tac provided for compatibility with HOL
  1591     (like the old excluded_middle_tac, but with subgoals swapped)
  1592 
  1593 
  1594 *** Internal programming interfaces ***
  1595 
  1596 * Pure: several new basic modules made available for general use, see
  1597 also src/Pure/README;
  1598 
  1599 * improved the theory data mechanism to support encapsulation (data
  1600 kind name replaced by private Object.kind, acting as authorization
  1601 key); new type-safe user interface via functor TheoryDataFun; generic
  1602 print_data function becomes basically useless;
  1603 
  1604 * removed global_names compatibility flag -- all theory declarations
  1605 are qualified by default;
  1606 
  1607 * module Pure/Syntax now offers quote / antiquote translation
  1608 functions (useful for Hoare logic etc. with implicit dependencies);
  1609 see HOL/ex/Antiquote for an example use;
  1610 
  1611 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1612 cterm -> thm;
  1613 
  1614 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1615 subgoal;
  1616 
  1617 * Display.print_goals function moved to Locale.print_goals;
  1618 
  1619 * standard print function for goals supports current_goals_markers
  1620 variable for marking begin of proof, end of proof, start of goal; the
  1621 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1622 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1623 for example;
  1624 
  1625 
  1626 
  1627 New in Isabelle98 (January 1998)
  1628 --------------------------------
  1629 
  1630 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1631 
  1632 * changed lexical syntax of terms / types: dots made part of long
  1633 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1634 
  1635 * simpset (and claset) reference variable replaced by functions
  1636 simpset / simpset_ref;
  1637 
  1638 * no longer supports theory aliases (via merge) and non-trivial
  1639 implicit merge of thms' signatures;
  1640 
  1641 * most internal names of constants changed due to qualified names;
  1642 
  1643 * changed Pure/Sequence interface (see Pure/seq.ML);
  1644 
  1645 
  1646 *** General Changes ***
  1647 
  1648 * hierachically structured name spaces (for consts, types, axms, thms
  1649 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1650 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1651 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1652 long_names for fully qualified output names; NOTE: ML programs
  1653 (special tactics, packages etc.) referring to internal names may have
  1654 to be adapted to cope with fully qualified names; in case of severe
  1655 backward campatibility problems try setting 'global_names' at compile
  1656 time to have enrything declared within a flat name space; one may also
  1657 fine tune name declarations in theories via the 'global' and 'local'
  1658 section;
  1659 
  1660 * reimplemented the implicit simpset and claset using the new anytype
  1661 data filed in signatures; references simpset:simpset ref etc. are
  1662 replaced by functions simpset:unit->simpset and
  1663 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1664 to patch your ML files accordingly;
  1665 
  1666 * HTML output now includes theory graph data for display with Java
  1667 applet or isatool browser; data generated automatically via isatool
  1668 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1669 
  1670 * defs may now be conditional; improved rewrite_goals_tac to handle
  1671 conditional equations;
  1672 
  1673 * defs now admits additional type arguments, using TYPE('a) syntax;
  1674 
  1675 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1676 creates a new theory node; implicit merge of thms' signatures is
  1677 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1678 transfer:theory->thm->thm in (rare) cases;
  1679 
  1680 * improved handling of draft signatures / theories; draft thms (and
  1681 ctyps, cterms) are automatically promoted to real ones;
  1682 
  1683 * slightly changed interfaces for oracles: admit many per theory, named
  1684 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1685 
  1686 * print_goals: optional output of const types (set show_consts and
  1687 show_types);
  1688 
  1689 * improved output of warnings (###) and errors (***);
  1690 
  1691 * subgoal_tac displays a warning if the new subgoal has type variables;
  1692 
  1693 * removed old README and Makefiles;
  1694 
  1695 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1696 
  1697 * removed obsolete init_pps and init_database;
  1698 
  1699 * deleted the obsolete tactical STATE, which was declared by
  1700     fun STATE tacfun st = tacfun st st;
  1701 
  1702 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1703 (which abbreviates $HOME);
  1704 
  1705 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1706 use isatool fixseq to adapt your ML programs (this works for fully
  1707 qualified references to the Sequence structure only!);
  1708 
  1709 * use_thy no longer requires writable current directory; it always
  1710 reloads .ML *and* .thy file, if either one is out of date;
  1711 
  1712 
  1713 *** Classical Reasoner ***
  1714 
  1715 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1716 tactics that use classical reasoning to simplify a subgoal without
  1717 splitting it into several subgoals;
  1718 
  1719 * Safe_tac: like safe_tac but uses the default claset;
  1720 
  1721 
  1722 *** Simplifier ***
  1723 
  1724 * added simplification meta rules:
  1725     (asm_)(full_)simplify: simpset -> thm -> thm;
  1726 
  1727 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1728 logics (again);
  1729 
  1730 * added prems argument to simplification procedures;
  1731 
  1732 * HOL, FOL, ZF: added infix function `addsplits':
  1733   instead of `<simpset> setloop (split_tac <thms>)'
  1734   you can simply write `<simpset> addsplits <thms>'
  1735 
  1736 
  1737 *** Syntax ***
  1738 
  1739 * TYPE('a) syntax for type reflection terms;
  1740 
  1741 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1742 
  1743 * pretty printer: changed order of mixfix annotation preference (again!);
  1744 
  1745 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1746 
  1747 
  1748 *** HOL ***
  1749 
  1750 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1751   with `addloop' of the simplifier to faciliate case splitting in premises.
  1752 
  1753 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1754 
  1755 * HOL/Auth: new protocol proofs including some for the Internet
  1756   protocol TLS;
  1757 
  1758 * HOL/Map: new theory of `maps' a la VDM;
  1759 
  1760 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1761 cancelling out common nat summands from =, <, <= (in)equalities, or
  1762 differences; simplification procedures nat_cancel_factor for
  1763 cancelling common factor from =, <, <= (in)equalities over natural
  1764 sums; nat_cancel contains both kinds of procedures, it is installed by
  1765 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1766 
  1767 * HOL/simplifier: terms of the form
  1768   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1769   are rewritten to
  1770   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1771   and those of the form
  1772   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1773   are rewritten to
  1774   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1775 
  1776 * HOL/datatype
  1777   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1778 
  1779   P(t_case f1 ... fn x) =
  1780      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1781         ...
  1782        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1783      )
  1784 
  1785   and a theorem `split_t_case_asm' of the form
  1786 
  1787   P(t_case f1 ... fn x) =
  1788     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1789         ...
  1790        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1791      )
  1792   which can be added to a simpset via `addsplits'. The existing theorems
  1793   expand_list_case and expand_option_case have been renamed to
  1794   split_list_case and split_option_case.
  1795 
  1796 * HOL/Arithmetic:
  1797   - `pred n' is automatically converted to `n-1'.
  1798     Users are strongly encouraged not to use `pred' any longer,
  1799     because it will disappear altogether at some point.
  1800   - Users are strongly encouraged to write "0 < n" rather than
  1801     "n ~= 0". Theorems and proof tools have been modified towards this
  1802     `standard'.
  1803 
  1804 * HOL/Lists:
  1805   the function "set_of_list" has been renamed "set" (and its theorems too);
  1806   the function "nth" now takes its arguments in the reverse order and
  1807   has acquired the infix notation "!" as in "xs!n".
  1808 
  1809 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1810 
  1811 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1812   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1813 
  1814 * HOL/record: extensible records with schematic structural subtyping
  1815 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1816 still lacks various theorems and concrete record syntax;
  1817 
  1818 
  1819 *** HOLCF ***
  1820 
  1821 * removed "axioms" and "generated by" sections;
  1822 
  1823 * replaced "ops" section by extended "consts" section, which is capable of
  1824   handling the continuous function space "->" directly;
  1825 
  1826 * domain package:
  1827   . proves theorems immediately and stores them in the theory,
  1828   . creates hierachical name space,
  1829   . now uses normal mixfix annotations (instead of cinfix...),
  1830   . minor changes to some names and values (for consistency),
  1831   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1832   . separator between mutual domain defs: changed "," to "and",
  1833   . improved handling of sort constraints;  now they have to
  1834     appear on the left-hand side of the equations only;
  1835 
  1836 * fixed LAM <x,y,zs>.b syntax;
  1837 
  1838 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1839 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1840 
  1841 
  1842 *** FOL and ZF ***
  1843 
  1844 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1845   with `addloop' of the simplifier to faciliate case splitting in premises.
  1846 
  1847 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1848 in HOL, they strip ALL and --> from proved theorems;
  1849 
  1850 
  1851 
  1852 New in Isabelle94-8 (May 1997)
  1853 ------------------------------
  1854 
  1855 *** General Changes ***
  1856 
  1857 * new utilities to build / run / maintain Isabelle etc. (in parts
  1858 still somewhat experimental); old Makefiles etc. still functional;
  1859 
  1860 * new 'Isabelle System Manual';
  1861 
  1862 * INSTALL text, together with ./configure and ./build scripts;
  1863 
  1864 * reimplemented type inference for greater efficiency, better error
  1865 messages and clean internal interface;
  1866 
  1867 * prlim command for dealing with lots of subgoals (an easier way of
  1868 setting goals_limit);
  1869 
  1870 
  1871 *** Syntax ***
  1872 
  1873 * supports alternative (named) syntax tables (parser and pretty
  1874 printer); internal interface is provided by add_modesyntax(_i);
  1875 
  1876 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1877 be used in conjunction with the Isabelle symbol font; uses the
  1878 "symbols" syntax table;
  1879 
  1880 * added token_translation interface (may translate name tokens in
  1881 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1882 the current print_mode); IMPORTANT: user print translation functions
  1883 are responsible for marking newly introduced bounds
  1884 (Syntax.mark_boundT);
  1885 
  1886 * token translations for modes "xterm" and "xterm_color" that display
  1887 names in bold, underline etc. or colors (which requires a color
  1888 version of xterm);
  1889 
  1890 * infixes may now be declared with names independent of their syntax;
  1891 
  1892 * added typed_print_translation (like print_translation, but may
  1893 access type of constant);
  1894 
  1895 
  1896 *** Classical Reasoner ***
  1897 
  1898 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1899 some limitations.  Blast_tac...
  1900   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1901   + ignores elimination rules that don't have the correct format
  1902         (the conclusion MUST be a formula variable)
  1903   + ignores types, which can make HOL proofs fail
  1904   + rules must not require higher-order unification, e.g. apply_type in ZF
  1905     [message "Function Var's argument not a bound variable" relates to this]
  1906   + its proof strategy is more general but can actually be slower
  1907 
  1908 * substitution with equality assumptions no longer permutes other
  1909 assumptions;
  1910 
  1911 * minor changes in semantics of addafter (now called addaltern); renamed
  1912 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1913 (and access functions for it);
  1914 
  1915 * improved combination of classical reasoner and simplifier:
  1916   + functions for handling clasimpsets
  1917   + improvement of addss: now the simplifier is called _after_ the
  1918     safe steps.
  1919   + safe variant of addss called addSss: uses safe simplifications
  1920     _during_ the safe steps. It is more complete as it allows multiple
  1921     instantiations of unknowns (e.g. with slow_tac).
  1922 
  1923 *** Simplifier ***
  1924 
  1925 * added interface for simplification procedures (functions that
  1926 produce *proven* rewrite rules on the fly, depending on current
  1927 redex);
  1928 
  1929 * ordering on terms as parameter (used for ordered rewriting);
  1930 
  1931 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1932 
  1933 * the solver is now split into a safe and an unsafe part.
  1934 This should be invisible for the normal user, except that the
  1935 functions setsolver and addsolver have been renamed to setSolver and
  1936 addSolver; added safe_asm_full_simp_tac;
  1937 
  1938 
  1939 *** HOL ***
  1940 
  1941 * a generic induction tactic `induct_tac' which works for all datatypes and
  1942 also for type `nat';
  1943 
  1944 * a generic case distinction tactic `exhaust_tac' which works for all
  1945 datatypes and also for type `nat';
  1946 
  1947 * each datatype comes with a function `size';
  1948 
  1949 * patterns in case expressions allow tuple patterns as arguments to
  1950 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1951 
  1952 * primrec now also works with type nat;
  1953 
  1954 * recdef: a new declaration form, allows general recursive functions to be
  1955 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1956 
  1957 * the constant for negation has been renamed from "not" to "Not" to
  1958 harmonize with FOL, ZF, LK, etc.;
  1959 
  1960 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1961 infinite lists;
  1962 
  1963 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1964 
  1965 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1966 problems in commutative rings, using axiomatic type classes for + and *;
  1967 
  1968 * more examples in HOL/MiniML and HOL/Auth;
  1969 
  1970 * more default rewrite rules for quantifiers, union/intersection;
  1971 
  1972 * a new constant `arbitrary == @x.False';
  1973 
  1974 * HOLCF/IOA replaces old HOL/IOA;
  1975 
  1976 * HOLCF changes: derived all rules and arities
  1977   + axiomatic type classes instead of classes
  1978   + typedef instead of faking type definitions
  1979   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1980   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1981   + eliminated the types void, one, tr
  1982   + use unit lift and bool lift (with translations) instead of one and tr
  1983   + eliminated blift from Lift3.thy (use Def instead of blift)
  1984   all eliminated rules are derived as theorems --> no visible changes ;
  1985 
  1986 
  1987 *** ZF ***
  1988 
  1989 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1990 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1991 as ZF_cs addSIs [equalityI];
  1992 
  1993 
  1994 
  1995 New in Isabelle94-7 (November 96)
  1996 ---------------------------------
  1997 
  1998 * allowing negative levels (as offsets) in prlev and choplev;
  1999 
  2000 * super-linear speedup for large simplifications;
  2001 
  2002 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2003 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2004 FAIL); can suppress it using the command Delsimps (ex_simps @
  2005 all_simps); De Morgan laws are also now included, by default;
  2006 
  2007 * improved printing of ==>  :  ~:
  2008 
  2009 * new object-logic "Sequents" adds linear logic, while replacing LK
  2010 and Modal (thanks to Sara Kalvala);
  2011 
  2012 * HOL/Auth: correctness proofs for authentication protocols;
  2013 
  2014 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2015 examples on HOL/Auth);
  2016 
  2017 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2018 the rewriter and classical reasoner simultaneously;
  2019 
  2020 * function uresult no longer returns theorems in "standard" format;
  2021 regain previous version by: val uresult = standard o uresult;
  2022 
  2023 
  2024 
  2025 New in Isabelle94-6
  2026 -------------------
  2027 
  2028 * oracles -- these establish an interface between Isabelle and trusted
  2029 external reasoners, which may deliver results as theorems;
  2030 
  2031 * proof objects (in particular record all uses of oracles);
  2032 
  2033 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2034 
  2035 * "constdefs" section in theory files;
  2036 
  2037 * "primrec" section (HOL) no longer requires names;
  2038 
  2039 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2040 
  2041 
  2042 
  2043 New in Isabelle94-5
  2044 -------------------
  2045 
  2046 * reduced space requirements;
  2047 
  2048 * automatic HTML generation from theories;
  2049 
  2050 * theory files no longer require "..." (quotes) around most types;
  2051 
  2052 * new examples, including two proofs of the Church-Rosser theorem;
  2053 
  2054 * non-curried (1994) version of HOL is no longer distributed;
  2055 
  2056 
  2057 
  2058 New in Isabelle94-4
  2059 -------------------
  2060 
  2061 * greatly reduced space requirements;
  2062 
  2063 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2064 
  2065 * searchable theorem database (see the section "Retrieving theorems" on
  2066 page 8 of the Reference Manual);
  2067 
  2068 * new examples, including Grabczewski's monumental case study of the
  2069 Axiom of Choice;
  2070 
  2071 * The previous version of HOL renamed to Old_HOL;
  2072 
  2073 * The new version of HOL (previously called CHOL) uses a curried syntax
  2074 for functions.  Application looks like f a b instead of f(a,b);
  2075 
  2076 * Mutually recursive inductive definitions finally work in HOL;
  2077 
  2078 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2079 translates to the operator "split";
  2080 
  2081 
  2082 
  2083 New in Isabelle94-3
  2084 -------------------
  2085 
  2086 * new infix operator, addss, allowing the classical reasoner to
  2087 perform simplification at each step of its search.  Example:
  2088         fast_tac (cs addss ss)
  2089 
  2090 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2091 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2092 look like (a,b) instead of <a,b>;
  2093 
  2094 * PLEASE NOTE: CHOL will eventually replace HOL!
  2095 
  2096 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2097 It translates to the operator "split".  A new theory of integers is available;
  2098 
  2099 * In ZF, integer numerals now denote two's-complement binary integers.
  2100 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2101 
  2102 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2103 of the Axiom of Choice;
  2104 
  2105 
  2106 
  2107 New in Isabelle94-2
  2108 -------------------
  2109 
  2110 * Significantly faster resolution;
  2111 
  2112 * the different sections in a .thy file can now be mixed and repeated
  2113 freely;
  2114 
  2115 * Database of theorems for FOL, HOL and ZF.  New
  2116 commands including qed, qed_goal and bind_thm store theorems in the database.
  2117 
  2118 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2119 a given theory (thms_of), or find out what theory a theorem was proved in
  2120 (theory_of_thm);
  2121 
  2122 * Bugs fixed in the inductive definition and datatype packages;
  2123 
  2124 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2125 and HOL_dup_cs obsolete;
  2126 
  2127 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2128 have been removed;
  2129 
  2130 * Simpler definition of function space in ZF;
  2131 
  2132 * new results about cardinal and ordinal arithmetic in ZF;
  2133 
  2134 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2135 types;
  2136 
  2137 
  2138 $Id$