NEWS
author nipkow
Thu Oct 10 19:03:37 2002 +0200 (2002-10-10)
changeset 13643 c82298745c20
parent 13618 12290bdce807
child 13644 7e09ff716dc9
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/simplifier:
    10 
    11   - Completely reimplemented Asm_full_simp_tac:
    12     Assumptions are now subject to complete mutual simplification,
    13     not just from left to right. The simplifier now preserves
    14     the order of assumptions.
    15 
    16     Potential INCOMPATIBILITY:
    17 
    18     -- Asm_full_simp_tac sometimes diverges where the old version did
    19        not, e.g. invoking Asm_full_simp_tac on the goal
    20 
    21         [| P (f x); y = x; f x = f y |] ==> Q
    22 
    23       now gives rise to the infinite reduction sequence
    24 
    25         P (f x) --(f x = f y)--> P (f y) --(y = x)--> P (f x) --(f x = f y)--> ...
    26 
    27       Using Asm_lr_simp_tac (or "simp (asm_lr)" in Isabelle/Isar) instead
    28       often solves this kind of problem.
    29 
    30     -- Tactics combining classical reasoner and simplification (such
    31        as auto) are also affected by this change, because many of them
    32        rely on Asm_full_simp_tac. They may sometimes diverge as well
    33        or yield a different numbers of subgoals. Try to use e.g. force,
    34        fastsimp, or safe instead of auto in case of problems. Sometimes
    35        subsequent calls to the classical reasoner will fail because a
    36        preceeding call to the simplifier too eagerly simplified the
    37        goal, e.g. deleted redundant premises.
    38 
    39   - The simplifier trace now shows the names of the applied rewrite rules
    40 
    41 * Pure: locale specifications now produce predicate definitions
    42 according to the body of text (covering assumptions modulo local
    43 definitions); predicate "loc_axioms" covers newly introduced text,
    44 while "loc" is cumulative wrt. all included locale expressions; the
    45 latter view is presented only on export into the global theory
    46 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    47 on the old view without predicates;
    48 
    49 * Pure: predefined locales "var" and "struct" are useful for sharing
    50 parameters (as in CASL, for example); just specify something like
    51 ``var x + var y + struct M'' as import;
    52 
    53 * Pure: improved thms_containing: proper indexing of facts instead of
    54 raw theorems; check validity of results wrt. current name space;
    55 include local facts of proof configuration (also covers active
    56 locales), cover fixed variables in index; may use "_" in term
    57 specification; an optional limit for the number of printed facts may
    58 be given (the default is 40);
    59 
    60 * Pure: disallow duplicate fact bindings within new-style theory files
    61 (batch-mode only);
    62 
    63 * Provers: improved induct method: assumptions introduced by case
    64 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    65 the goal statement); "foo" still refers to all facts collectively;
    66 
    67 * Provers: the function blast.overloaded has been removed: all constants
    68 are regarded as potentially overloaded, which improves robustness in exchange
    69 for slight decrease in efficiency;
    70 
    71 * Isar: preview of problems to finish 'show' now produce an error
    72 rather than just a warning (in interactive mode);
    73 
    74 
    75 *** HOL ***
    76 
    77 * new flag trace_unify_fail causes unification to print diagnostic
    78 information (PG: in trace buffer) when it fails. This is useful for
    79 figuring out why single step proofs like rule, erule or assumption
    80 failed.
    81 
    82 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
    83 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
    84 
    85 * 'typedef' command has new option "open" to suppress the set
    86 definition;
    87 
    88 * functions Min and Max on finite sets have been introduced (theory
    89 Finite_Set);
    90 
    91 * attribute [symmetric] now works for relations as well; it turns
    92 (x,y) : R^-1 into (y,x) : R, and vice versa;
    93 
    94 * arith(_tac) now produces a counter example if it cannot prove a theorem.
    95   In ProofGeneral the counter example appears in the trace buffer.
    96 
    97 * arith(_tac) does now know about div k and mod k where k is a numeral
    98 of type nat or int. It can solve simple goals like
    99 
   100   "0 < n ==> n div 2 < (n::nat)"
   101 
   102 but fails if divisibility plays a role like in
   103 
   104   "n div 2 + (n+1) div 2 = (n::nat)"
   105 
   106 * simp's arithmetic capabilities have been enhanced a bit: it now
   107 takes ~= in premises into account (by performing a case split);
   108 
   109 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   110 are distributed over a sum of terms;
   111 
   112 * induct over a !!-quantified statement (say !!x1..xn):
   113   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   114 
   115 * GroupTheory: converted to Isar theories, using locales with implicit structures;
   116 
   117 * Real/HahnBanach: updated and adapted to locales;
   118 
   119 
   120 *** ZF ***
   121 
   122 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   123 universe, etc.);
   124 
   125 * Main ZF: many theories converted to new-style format;
   126 
   127 
   128 *** ML ***
   129 
   130 * Pure: Tactic.prove provides sane interface for internal proofs;
   131 omits the infamous "standard" operation, so this is more appropriate
   132 than prove_goalw_cterm in many situations (e.g. in simprocs);
   133 
   134 * Pure: improved error reporting of simprocs;
   135 
   136 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   137 up simprocs;
   138 
   139 
   140 
   141 New in Isabelle2002 (March 2002)
   142 --------------------------------
   143 
   144 *** Document preparation ***
   145 
   146 * greatly simplified document preparation setup, including more
   147 graceful interpretation of isatool usedir -i/-d/-D options, and more
   148 instructive isatool mkdir; users should basically be able to get
   149 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   150 users may run a separate document processing stage manually like this:
   151 "isatool usedir -D output HOL Test && isatool document Test/output";
   152 
   153 * theory dependency graph may now be incorporated into documents;
   154 isatool usedir -g true will produce session_graph.eps/.pdf for use
   155 with \includegraphics of LaTeX;
   156 
   157 * proper spacing of consecutive markup elements, especially text
   158 blocks after section headings;
   159 
   160 * support bold style (for single symbols only), input syntax is like
   161 this: "\<^bold>\<alpha>" or "\<^bold>A";
   162 
   163 * \<bullet> is now output as bold \cdot by default, which looks much
   164 better in printed text;
   165 
   166 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   167 note that these symbols are currently unavailable in Proof General /
   168 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   169 
   170 * isatool latex no longer depends on changed TEXINPUTS, instead
   171 isatool document copies the Isabelle style files to the target
   172 location;
   173 
   174 
   175 *** Isar ***
   176 
   177 * Pure/Provers: improved proof by cases and induction;
   178   - 'case' command admits impromptu naming of parameters (such as
   179     "case (Suc n)");
   180   - 'induct' method divinates rule instantiation from the inductive
   181     claim; no longer requires excessive ?P bindings for proper
   182     instantiation of cases;
   183   - 'induct' method properly enumerates all possibilities of set/type
   184     rules; as a consequence facts may be also passed through *type*
   185     rules without further ado;
   186   - 'induct' method now derives symbolic cases from the *rulified*
   187     rule (before it used to rulify cases stemming from the internal
   188     atomized version); this means that the context of a non-atomic
   189     statement becomes is included in the hypothesis, avoiding the
   190     slightly cumbersome show "PROP ?case" form;
   191   - 'induct' may now use elim-style induction rules without chaining
   192     facts, using ``missing'' premises from the goal state; this allows
   193     rules stemming from inductive sets to be applied in unstructured
   194     scripts, while still benefitting from proper handling of non-atomic
   195     statements; NB: major inductive premises need to be put first, all
   196     the rest of the goal is passed through the induction;
   197   - 'induct' proper support for mutual induction involving non-atomic
   198     rule statements (uses the new concept of simultaneous goals, see
   199     below);
   200   - append all possible rule selections, but only use the first
   201     success (no backtracking);
   202   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   203   - undeclared rule case names default to numbers 1, 2, 3, ...;
   204   - added 'print_induct_rules' (covered by help item in recent Proof
   205     General versions);
   206   - moved induct/cases attributes to Pure, methods to Provers;
   207   - generic method setup instantiated for FOL and HOL;
   208 
   209 * Pure: support multiple simultaneous goal statements, for example
   210 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   211 meta-level mechanism, this acts as if several individual goals had
   212 been stated separately; in particular common proof methods need to be
   213 repeated in order to cover all claims; note that a single elimination
   214 step is *not* sufficient to establish the two conjunctions, so this
   215 fails:
   216 
   217   assume "A & B" then have A and B ..   (*".." fails*)
   218 
   219 better use "obtain" in situations as above; alternative refer to
   220 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   221 
   222 * Pure: proper integration with ``locales''; unlike the original
   223 version by Florian Kammüller, Isar locales package high-level proof
   224 contexts rather than raw logical ones (e.g. we admit to include
   225 attributes everywhere); operations on locales include merge and
   226 rename; support for implicit arguments (``structures''); simultaneous
   227 type-inference over imports and text; see also HOL/ex/Locales.thy for
   228 some examples;
   229 
   230 * Pure: the following commands have been ``localized'', supporting a
   231 target locale specification "(in name)": 'lemma', 'theorem',
   232 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   233 stored both within the locale and at the theory level (exported and
   234 qualified by the locale name);
   235 
   236 * Pure: theory goals may now be specified in ``long'' form, with
   237 ad-hoc contexts consisting of arbitrary locale elements. for example
   238 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   239 definitions may be given, too); the result is a meta-level rule with
   240 the context elements being discharged in the obvious way;
   241 
   242 * Pure: new proof command 'using' allows to augment currently used
   243 facts after a goal statement ('using' is syntactically analogous to
   244 'apply', but acts on the goal's facts only); this allows chained facts
   245 to be separated into parts given before and after a claim, as in
   246 ``from a and b have C using d and e <proof>'';
   247 
   248 * Pure: renamed "antecedent" case to "rule_context";
   249 
   250 * Pure: new 'judgment' command records explicit information about the
   251 object-logic embedding (used by several tools internally); no longer
   252 use hard-wired "Trueprop";
   253 
   254 * Pure: added 'corollary' command;
   255 
   256 * Pure: fixed 'token_translation' command;
   257 
   258 * Pure: removed obsolete 'exported' attribute;
   259 
   260 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   261 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   262 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   263 
   264 * Pure: method 'atomize' presents local goal premises as object-level
   265 statements (atomic meta-level propositions); setup controlled via
   266 rewrite rules declarations of 'atomize' attribute; example
   267 application: 'induct' method with proper rule statements in improper
   268 proof *scripts*;
   269 
   270 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   271 now consider the syntactic context of assumptions, giving a better
   272 chance to get type-inference of the arguments right (this is
   273 especially important for locales);
   274 
   275 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   276 mode;
   277 
   278 * Pure/obtain: the formal conclusion "thesis", being marked as
   279 ``internal'', may no longer be reference directly in the text;
   280 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   281 situations;
   282 
   283 * Pure: generic 'sym' attribute which declares a rule both as pure
   284 'elim?' and for the 'symmetric' operation;
   285 
   286 * Pure: marginal comments ``--'' may now occur just anywhere in the
   287 text; the fixed correlation with particular command syntax has been
   288 discontinued;
   289 
   290 * Pure: new method 'rules' is particularly well-suited for proof
   291 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   292 but often produces more compact proof terms with less detours;
   293 
   294 * Pure/Provers/classical: simplified integration with pure rule
   295 attributes and methods; the classical "intro?/elim?/dest?"
   296 declarations coincide with the pure ones; the "rule" method no longer
   297 includes classically swapped intros; "intro" and "elim" methods no
   298 longer pick rules from the context; also got rid of ML declarations
   299 AddXIs/AddXEs/AddXDs; all of this has some potential for
   300 INCOMPATIBILITY;
   301 
   302 * Provers/classical: attribute 'swapped' produces classical inversions
   303 of introduction rules;
   304 
   305 * Provers/simplifier: 'simplified' attribute may refer to explicit
   306 rules instead of full simplifier context; 'iff' attribute handles
   307 conditional rules;
   308 
   309 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   310 
   311 * HOL: 'recdef' now fails on unfinished automated proofs, use
   312 "(permissive)" option to recover old behavior;
   313 
   314 * HOL: 'inductive' no longer features separate (collective) attributes
   315 for 'intros' (was found too confusing);
   316 
   317 * HOL: properly declared induction rules less_induct and
   318 wf_induct_rule;
   319 
   320 
   321 *** HOL ***
   322 
   323 * HOL: moved over to sane numeral syntax; the new policy is as
   324 follows:
   325 
   326   - 0 and 1 are polymorphic constants, which are defined on any
   327   numeric type (nat, int, real etc.);
   328 
   329   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   330   binary representation internally;
   331 
   332   - type nat has special constructor Suc, and generally prefers Suc 0
   333   over 1::nat and Suc (Suc 0) over 2::nat;
   334 
   335 This change may cause significant problems of INCOMPATIBILITY; here
   336 are some hints on converting existing sources:
   337 
   338   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   339   entities, so expressions involving "-" (unary or binary minus) need
   340   to be spaced properly;
   341 
   342   - existing occurrences of "1" may need to be constraint "1::nat" or
   343   even replaced by Suc 0; similar for old "2";
   344 
   345   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   346 
   347   - remove all special provisions on numerals in proofs;
   348 
   349 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   350 representation (depends on bin_arith_simps in the default context);
   351 
   352 * HOL: symbolic syntax for x^2 (numeral 2);
   353 
   354 * HOL: the class of all HOL types is now called "type" rather than
   355 "term"; INCOMPATIBILITY, need to adapt references to this type class
   356 in axclass/classes, instance/arities, and (usually rare) occurrences
   357 in typings (of consts etc.); internally the class is called
   358 "HOL.type", ML programs should refer to HOLogic.typeS;
   359 
   360 * HOL/record package improvements:
   361   - new derived operations "fields" to build a partial record section,
   362     "extend" to promote a fixed record to a record scheme, and
   363     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   364     declared as simp by default;
   365   - shared operations ("more", "fields", etc.) now need to be always
   366     qualified) --- potential INCOMPATIBILITY;
   367   - removed "make_scheme" operations (use "make" with "extend") --
   368     INCOMPATIBILITY;
   369   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   370   - provides cases/induct rules for use with corresponding Isar
   371     methods (for concrete records, record schemes, concrete more
   372     parts, and schematic more parts -- in that order);
   373   - internal definitions directly based on a light-weight abstract
   374     theory of product types over typedef rather than datatype;
   375 
   376 * HOL: generic code generator for generating executable ML code from
   377 specifications; specific support for HOL constructs such as inductive
   378 datatypes and sets, as well as recursive functions; can be invoked
   379 via 'generate_code' theory section;
   380 
   381 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   382 
   383 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   384 (beware of argument permutation!);
   385 
   386 * HOL: linorder_less_split superseded by linorder_cases;
   387 
   388 * HOL/List: "nodups" renamed to "distinct";
   389 
   390 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   391 to peripheral theory "Hilbert_Choice";
   392 
   393 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   394 in this (rare) case use:
   395 
   396   delSWrapper "split_all_tac"
   397   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   398 
   399 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   400 MAY FAIL;
   401 
   402 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   403 Isabelle's type classes, ^ on functions and relations has too general
   404 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   405 necessary to attach explicit type constraints;
   406 
   407 * HOL/Relation: the prefix name of the infix "O" has been changed from
   408 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   409 renamed accordingly (eg "compI" -> "rel_compI").
   410 
   411 * HOL: syntax translations now work properly with numerals and records
   412 expressions;
   413 
   414 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   415 of "lam" -- INCOMPATIBILITY;
   416 
   417 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   418 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   419 renamed "Product_Type.unit";
   420 
   421 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   422 
   423 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   424 the "cases" method);
   425 
   426 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   427 Florian Kammüller);
   428 
   429 * HOL/IMP: updated and converted to new-style theory format; several
   430 parts turned into readable document, with proper Isar proof texts and
   431 some explanations (by Gerwin Klein);
   432 
   433 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   434 
   435 * HOL-Hyperreal is now a logic image;
   436 
   437 
   438 *** HOLCF ***
   439 
   440 * Isar: consts/constdefs supports mixfix syntax for continuous
   441 operations;
   442 
   443 * Isar: domain package adapted to new-style theory format, e.g. see
   444 HOLCF/ex/Dnat.thy;
   445 
   446 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   447 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   448 lift.induct_tac, always use UU instead of Undef;
   449 
   450 * HOLCF/IMP: updated and converted to new-style theory;
   451 
   452 
   453 *** ZF ***
   454 
   455 * Isar: proper integration of logic-specific tools and packages,
   456 including theory commands '(co)inductive', '(co)datatype',
   457 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   458 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   459 
   460 * theory Main no longer includes AC; for the Axiom of Choice, base
   461 your theory on Main_ZFC;
   462 
   463 * the integer library now covers quotients and remainders, with many
   464 laws relating division to addition, multiplication, etc.;
   465 
   466 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   467 typeless version of the formalism;
   468 
   469 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   470 format;
   471 
   472 * ZF/Induct: new directory for examples of inductive definitions,
   473 including theory Multiset for multiset orderings; converted to
   474 new-style theory format;
   475 
   476 * ZF: many new theorems about lists, ordinals, etc.;
   477 
   478 
   479 *** General ***
   480 
   481 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   482 variable proof controls level of detail: 0 = no proofs (only oracle
   483 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   484 also ref manual for further ML interfaces;
   485 
   486 * Pure/axclass: removed obsolete ML interface
   487 goal_subclass/goal_arity;
   488 
   489 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   490 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   491 separate tokens, so expressions involving minus need to be spaced
   492 properly;
   493 
   494 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   495 rather than "infixl" or "infixr";
   496 
   497 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   498 sort constraint specifications in type inference; e.g. "x::_::foo"
   499 ensures that the type of "x" is of sort "foo" (but not necessarily a
   500 type variable);
   501 
   502 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   503 control output of nested => (types); the default behavior is
   504 "type_brackets";
   505 
   506 * Pure/syntax: builtin parse translation for "_constify" turns valued
   507 tokens into AST constants;
   508 
   509 * Pure/syntax: prefer later declarations of translations and print
   510 translation functions; potential INCOMPATIBILITY: need to reverse
   511 multiple declarations for same syntax element constant;
   512 
   513 * Pure/show_hyps reset by default (in accordance to existing Isar
   514 practice);
   515 
   516 * Provers/classical: renamed addaltern to addafter, addSaltern to
   517 addSafter;
   518 
   519 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   520 as well;
   521 
   522 * system: tested support for MacOS X; should be able to get Isabelle +
   523 Proof General to work in a plain Terminal after installing Poly/ML
   524 (e.g. from the Isabelle distribution area) and GNU bash alone
   525 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   526 support requires further installations, e.g. from
   527 http://fink.sourceforge.net/);
   528 
   529 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   530 
   531 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   532 of 40 MB), cf. ML_OPTIONS;
   533 
   534 * system: Proof General keywords specification is now part of the
   535 Isabelle distribution (see etc/isar-keywords.el);
   536 
   537 * system: support for persistent Proof General sessions (refrain from
   538 outdating all loaded theories on startup); user may create writable
   539 logic images like this: ``isabelle -q HOL Test'';
   540 
   541 * system: smart selection of Isabelle process versus Isabelle
   542 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   543 run both "isabelle" and "Isabelle" even if file names are badly
   544 damaged (executable inspects the case of the first letter of its own
   545 name); added separate "isabelle-process" and "isabelle-interface";
   546 
   547 * system: refrain from any attempt at filtering input streams; no
   548 longer support ``8bit'' encoding of old isabelle font, instead proper
   549 iso-latin characters may now be used; the related isatools
   550 "symbolinput" and "nonascii" have disappeared as well;
   551 
   552 * system: removed old "xterm" interface (the print modes "xterm" and
   553 "xterm_color" are still available for direct use in a suitable
   554 terminal);
   555 
   556 
   557 
   558 New in Isabelle99-2 (February 2001)
   559 -----------------------------------
   560 
   561 *** Overview of INCOMPATIBILITIES ***
   562 
   563 * HOL: please note that theories in the Library and elsewhere often use the
   564 new-style (Isar) format; to refer to their theorems in an ML script you must
   565 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   566 
   567 * HOL: inductive package no longer splits induction rule aggressively,
   568 but only as far as specified by the introductions given; the old
   569 format may be recovered via ML function complete_split_rule or attribute
   570 'split_rule (complete)';
   571 
   572 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   573 gfp_Tarski to gfp_unfold;
   574 
   575 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   576 
   577 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   578 relation); infix "^^" has been renamed "``"; infix "``" has been
   579 renamed "`"; "univalent" has been renamed "single_valued";
   580 
   581 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   582 operation;
   583 
   584 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   585 
   586 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   587 
   588 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   589 consequence, it is no longer monotonic wrt. the local goal context
   590 (which is now passed through the inductive cases);
   591 
   592 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   593 \<gg> to \<ggreater>;
   594 
   595 
   596 *** Document preparation ***
   597 
   598 * \isabellestyle{NAME} selects version of Isabelle output (currently
   599 available: are "it" for near math-mode best-style output, "sl" for
   600 slanted text style, and "tt" for plain type-writer; if no
   601 \isabellestyle command is given, output is according to slanted
   602 type-writer);
   603 
   604 * support sub/super scripts (for single symbols only), input syntax is
   605 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   606 
   607 * some more standard symbols; see Appendix A of the system manual for
   608 the complete list of symbols defined in isabellesym.sty;
   609 
   610 * improved isabelle style files; more abstract symbol implementation
   611 (should now use \isamath{...} and \isatext{...} in custom symbol
   612 definitions);
   613 
   614 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   615 state; Note that presentation of goal states does not conform to
   616 actual human-readable proof documents.  Please do not include goal
   617 states into document output unless you really know what you are doing!
   618 
   619 * proper indentation of antiquoted output with proportional LaTeX
   620 fonts;
   621 
   622 * no_document ML operator temporarily disables LaTeX document
   623 generation;
   624 
   625 * isatool unsymbolize tunes sources for plain ASCII communication;
   626 
   627 
   628 *** Isar ***
   629 
   630 * Pure: Isar now suffers initial goal statements to contain unbound
   631 schematic variables (this does not conform to actual readable proof
   632 documents, due to unpredictable outcome and non-compositional proof
   633 checking); users who know what they are doing may use schematic goals
   634 for Prolog-style synthesis of proven results;
   635 
   636 * Pure: assumption method (an implicit finishing) now handles actual
   637 rules as well;
   638 
   639 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   640 initial goal, declare "that" only as Pure intro (only for single
   641 steps); the "that" rule assumption may now be involved in implicit
   642 finishing, thus ".." becomes a feasible for trivial obtains;
   643 
   644 * Pure: default proof step now includes 'intro_classes'; thus trivial
   645 instance proofs may be performed by "..";
   646 
   647 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   648 statements as well;
   649 
   650 * Pure: more robust selection of calculational rules;
   651 
   652 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   653 rule (as well as the assumption rule);
   654 
   655 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   656 lemmas, using the graph browser tool;
   657 
   658 * Pure: predict failure of "show" in interactive mode;
   659 
   660 * Pure: 'thms_containing' now takes actual terms as arguments;
   661 
   662 * HOL: improved method 'induct' --- now handles non-atomic goals
   663 (potential INCOMPATIBILITY); tuned error handling;
   664 
   665 * HOL: cases and induct rules now provide explicit hints about the
   666 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   667 any remaining facts are inserted into the goal verbatim;
   668 
   669 * HOL: local contexts (aka cases) may now contain term bindings as
   670 well; the 'cases' and 'induct' methods new provide a ?case binding for
   671 the result to be shown in each case;
   672 
   673 * HOL: added 'recdef_tc' command;
   674 
   675 * isatool convert assists in eliminating legacy ML scripts;
   676 
   677 
   678 *** HOL ***
   679 
   680 * HOL/Library: a collection of generic theories to be used together
   681 with main HOL; the theory loader path already includes this directory
   682 by default; the following existing theories have been moved here:
   683 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   684 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   685 
   686 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   687 modelling and verification task performed in Isabelle/HOL +
   688 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   689 
   690 * HOL/Algebra: special summation operator SUM no longer exists, it has
   691 been replaced by setsum; infix 'assoc' now has priority 50 (like
   692 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   693 'domain', this makes the theory consistent with mathematical
   694 literature;
   695 
   696 * HOL basics: added overloaded operations "inverse" and "divide"
   697 (infix "/"), syntax for generic "abs" operation, generic summation
   698 operator \<Sum>;
   699 
   700 * HOL/typedef: simplified package, provide more useful rules (see also
   701 HOL/subset.thy);
   702 
   703 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   704 now expressed as a proper nested rule (old-style tactic scripts may
   705 require atomize_strip_tac to cope with non-atomic premises);
   706 
   707 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   708 to "split_conv" (old name still available for compatibility);
   709 
   710 * HOL: improved concrete syntax for strings (e.g. allows translation
   711 rules with string literals);
   712 
   713 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   714  and Fleuriot's mechanization of analysis, including the transcendental
   715  functions for the reals;
   716 
   717 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   718 
   719 
   720 *** CTT ***
   721 
   722 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   723 "lam" is displayed as TWO lambda-symbols
   724 
   725 * CTT: theory Main now available, containing everything (that is, Bool
   726 and Arith);
   727 
   728 
   729 *** General ***
   730 
   731 * Pure: the Simplifier has been implemented properly as a derived rule
   732 outside of the actual kernel (at last!); the overall performance
   733 penalty in practical applications is about 50%, while reliability of
   734 the Isabelle inference kernel has been greatly improved;
   735 
   736 * print modes "brackets" and "no_brackets" control output of nested =>
   737 (types) and ==> (props); the default behaviour is "brackets";
   738 
   739 * Provers: fast_tac (and friends) now handle actual object-logic rules
   740 as assumptions as well;
   741 
   742 * system: support Poly/ML 4.0;
   743 
   744 * system: isatool install handles KDE version 1 or 2;
   745 
   746 
   747 
   748 New in Isabelle99-1 (October 2000)
   749 ----------------------------------
   750 
   751 *** Overview of INCOMPATIBILITIES ***
   752 
   753 * HOL: simplification of natural numbers is much changed; to partly
   754 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   755 issue the following ML commands:
   756 
   757   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   758   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   759 
   760 * HOL: simplification no longer dives into case-expressions; this is
   761 controlled by "t.weak_case_cong" for each datatype t;
   762 
   763 * HOL: nat_less_induct renamed to less_induct;
   764 
   765 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   766 fixsome to patch .thy and .ML sources automatically;
   767 
   768   select_equality  -> some_equality
   769   select_eq_Ex     -> some_eq_ex
   770   selectI2EX       -> someI2_ex
   771   selectI2         -> someI2
   772   selectI          -> someI
   773   select1_equality -> some1_equality
   774   Eps_sym_eq       -> some_sym_eq_trivial
   775   Eps_eq           -> some_eq_trivial
   776 
   777 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   778 
   779 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   780 instead);
   781 
   782 * HOL: the recursion equations generated by 'recdef' are now called
   783 f.simps instead of f.rules;
   784 
   785 * HOL: qed_spec_mp now also handles bounded ALL as well;
   786 
   787 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   788 sometimes be needed;
   789 
   790 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   791 
   792 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   793 
   794 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   795 product is now "<*>" instead of "Times"; the lexicographic product is
   796 now "<*lex*>" instead of "**";
   797 
   798 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   799 of main HOL, but was unused); better use HOL's datatype package;
   800 
   801 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   802 the old syntax may be recovered as follows:
   803 
   804   syntax (symbols)
   805     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   806       (infixl "\\<oplus>" 100)
   807 
   808 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   809 
   810 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   811 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   812 internally;
   813 
   814 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   815 changed from A/r to A//r;
   816 
   817 * ZF: new treatment of arithmetic (nat & int) may break some old
   818 proofs;
   819 
   820 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   821 rulify -> rule_format, elimify -> elim_format, ...);
   822 
   823 * Isar/Provers: intro/elim/dest attributes changed; renamed
   824 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   825 should have to change intro!! to intro? only); replaced "delrule" by
   826 "rule del";
   827 
   828 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   829 
   830 * Provers: strengthened force_tac by using new first_best_tac;
   831 
   832 * LaTeX document preparation: several changes of isabelle.sty (see
   833 lib/texinputs);
   834 
   835 
   836 *** Document preparation ***
   837 
   838 * formal comments (text blocks etc.) in new-style theories may now
   839 contain antiquotations of thm/prop/term/typ/text to be presented
   840 according to latex print mode; concrete syntax is like this:
   841 @{term[show_types] "f(x) = a + x"};
   842 
   843 * isatool mkdir provides easy setup of Isabelle session directories,
   844 including proper document sources;
   845 
   846 * generated LaTeX sources are now deleted after successful run
   847 (isatool document -c); may retain a copy somewhere else via -D option
   848 of isatool usedir;
   849 
   850 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   851 style files, achieving self-contained LaTeX sources and simplifying
   852 LaTeX debugging;
   853 
   854 * old-style theories now produce (crude) LaTeX output as well;
   855 
   856 * browser info session directories are now self-contained (may be put
   857 on WWW server seperately); improved graphs of nested sessions; removed
   858 graph for 'all sessions';
   859 
   860 * several improvements in isabelle style files; \isabellestyle{it}
   861 produces fake math mode output; \isamarkupheader is now \section by
   862 default; see lib/texinputs/isabelle.sty etc.;
   863 
   864 
   865 *** Isar ***
   866 
   867 * Isar/Pure: local results and corresponding term bindings are now
   868 subject to Hindley-Milner polymorphism (similar to ML); this
   869 accommodates incremental type-inference very nicely;
   870 
   871 * Isar/Pure: new derived language element 'obtain' supports
   872 generalized existence reasoning;
   873 
   874 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   875 support accumulation of results, without applying any rules yet;
   876 useful to collect intermediate results without explicit name
   877 references, and for use with transitivity rules with more than 2
   878 premises;
   879 
   880 * Isar/Pure: scalable support for case-analysis type proofs: new
   881 'case' language element refers to local contexts symbolically, as
   882 produced by certain proof methods; internally, case names are attached
   883 to theorems as "tags";
   884 
   885 * Isar/Pure: theory command 'hide' removes declarations from
   886 class/type/const name spaces;
   887 
   888 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   889 indicate potential overloading;
   890 
   891 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   892 
   893 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   894 "{a,b,c}" instead of {a,b,c};
   895 
   896 * Isar/Pure now provides its own version of intro/elim/dest
   897 attributes; useful for building new logics, but beware of confusion
   898 with the version in Provers/classical;
   899 
   900 * Isar/Pure: the local context of (non-atomic) goals is provided via
   901 case name 'antecedent';
   902 
   903 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   904 to the current context is now done automatically);
   905 
   906 * Isar/Pure: theory command 'method_setup' provides a simple interface
   907 for definining proof methods in ML;
   908 
   909 * Isar/Provers: intro/elim/dest attributes changed; renamed
   910 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   911 most cases, one should have to change intro!! to intro? only);
   912 replaced "delrule" by "rule del";
   913 
   914 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   915 'symmetric' attribute (the latter supercedes [RS sym]);
   916 
   917 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   918 method modifier); 'simp' method: 'only:' modifier removes loopers as
   919 well (including splits);
   920 
   921 * Isar/Provers: Simplifier and Classical methods now support all kind
   922 of modifiers used in the past, including 'cong', 'iff', etc.
   923 
   924 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   925 of Simplifier and Classical reasoner);
   926 
   927 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   928 now support named cases; major packages (inductive, datatype, primrec,
   929 recdef) support case names and properly name parameters;
   930 
   931 * Isar/HOL: new transitivity rules for substitution in inequalities --
   932 monotonicity conditions are extracted to be proven at end of
   933 calculations;
   934 
   935 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   936 method anyway;
   937 
   938 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   939 split_if split_if_asm; datatype package provides theorems foo.splits =
   940 foo.split foo.split_asm for each datatype;
   941 
   942 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   943 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   944 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   945 use "(cases (simplified))" method in proper proof texts);
   946 
   947 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   948 
   949 * Isar: names of theorems etc. may be natural numbers as well;
   950 
   951 * Isar: 'pr' command: optional arguments for goals_limit and
   952 ProofContext.prems_limit; no longer prints theory contexts, but only
   953 proof states;
   954 
   955 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   956 additional print modes to be specified; e.g. "pr(latex)" will print
   957 proof state according to the Isabelle LaTeX style;
   958 
   959 * Isar: improved support for emulating tactic scripts, including proof
   960 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   961 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   962 (for HOL datatypes);
   963 
   964 * Isar: simplified (more robust) goal selection of proof methods: 1st
   965 goal, all goals, or explicit goal specifier (tactic emulation); thus
   966 'proof method scripts' have to be in depth-first order;
   967 
   968 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   969 
   970 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   971 should instead use individual commands for printing items
   972 (print_commands, print_methods etc.);
   973 
   974 * Isar: added 'nothing' --- the empty list of theorems;
   975 
   976 
   977 *** HOL ***
   978 
   979 * HOL/MicroJava: formalization of a fragment of Java, together with a
   980 corresponding virtual machine and a specification of its bytecode
   981 verifier and a lightweight bytecode verifier, including proofs of
   982 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   983 Cornelia Pusch (see also the homepage of project Bali at
   984 http://isabelle.in.tum.de/Bali/);
   985 
   986 * HOL/Algebra: new theory of rings and univariate polynomials, by
   987 Clemens Ballarin;
   988 
   989 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   990 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   991 Rasmussen;
   992 
   993 * HOL/Lattice: fundamental concepts of lattice theory and order
   994 structures, including duals, properties of bounds versus algebraic
   995 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   996 Theorem for complete lattices etc.; may also serve as a demonstration
   997 for abstract algebraic reasoning using axiomatic type classes, and
   998 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   999 
  1000 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1001 von Oheimb;
  1002 
  1003 * HOL/IMPP: extension of IMP with local variables and mutually
  1004 recursive procedures, by David von Oheimb;
  1005 
  1006 * HOL/Lambda: converted into new-style theory and document;
  1007 
  1008 * HOL/ex/Multiquote: example of multiple nested quotations and
  1009 anti-quotations -- basically a generalized version of de-Bruijn
  1010 representation; very useful in avoiding lifting of operations;
  1011 
  1012 * HOL/record: added general record equality rule to simpset; fixed
  1013 select-update simplification procedure to handle extended records as
  1014 well; admit "r" as field name;
  1015 
  1016 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1017 other numeric types and also as the identity of groups, rings, etc.;
  1018 
  1019 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1020 Types nat and int belong to this axclass;
  1021 
  1022 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1023    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1024    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1025   two terms #m*u and #n*u are replaced by #(m+n)*u
  1026     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1027   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1028     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1029 
  1030 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1031 powerful prover for predicate logic but knows nothing of clasets; see
  1032 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1033 
  1034 * HOL: new version of "case_tac" subsumes both boolean case split and
  1035 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1036 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1037 
  1038 * HOL: simplification no longer dives into case-expressions: only the
  1039 selector expression is simplified, but not the remaining arms; to
  1040 enable full simplification of case-expressions for datatype t, you may
  1041 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1042 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1043 
  1044 * HOL/recdef: the recursion equations generated by 'recdef' for
  1045 function 'f' are now called f.simps instead of f.rules; if all
  1046 termination conditions are proved automatically, these simplification
  1047 rules are added to the simpset, as in primrec; rules may be named
  1048 individually as well, resulting in a separate list of theorems for
  1049 each equation;
  1050 
  1051 * HOL/While is a new theory that provides a while-combinator. It
  1052 permits the definition of tail-recursive functions without the
  1053 provision of a termination measure. The latter is necessary once the
  1054 invariant proof rule for while is applied.
  1055 
  1056 * HOL: new (overloaded) notation for the set of elements below/above
  1057 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1058 
  1059 * HOL: theorems impI, allI, ballI bound as "strip";
  1060 
  1061 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1062 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1063 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1064 
  1065 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1066 
  1067 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1068 main HOL, but was unused);
  1069 
  1070 * HOL: fewer consts declared as global (e.g. have to refer to
  1071 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1072 
  1073 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1074 in case of overlap with user translations (e.g. judgements over
  1075 tuples); (note that the underlying logical represenation is still
  1076 bogus);
  1077 
  1078 
  1079 *** ZF ***
  1080 
  1081 * ZF: simplification automatically cancels common terms in arithmetic
  1082 expressions over nat and int;
  1083 
  1084 * ZF: new treatment of nat to minimize type-checking: all operators
  1085 coerce their operands to a natural number using the function natify,
  1086 making the algebraic laws unconditional;
  1087 
  1088 * ZF: as above, for int: operators coerce their operands to an integer
  1089 using the function intify;
  1090 
  1091 * ZF: the integer library now contains many of the usual laws for the
  1092 orderings, including $<=, and monotonicity laws for $+ and $*;
  1093 
  1094 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1095 simplification;
  1096 
  1097 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1098 to the simplifier and classical reasoner simultaneously;
  1099 
  1100 
  1101 *** General ***
  1102 
  1103 * Provers: blast_tac now handles actual object-logic rules as
  1104 assumptions; note that auto_tac uses blast_tac internally as well;
  1105 
  1106 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1107 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1108 
  1109 * Provers: delrules now handles destruct rules as well (no longer need
  1110 explicit make_elim);
  1111 
  1112 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1113   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1114 use instead the strong form,
  1115   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1116 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1117 from destruct-rules;
  1118 
  1119 * Provers: Simplifier.easy_setup provides a fast path to basic
  1120 Simplifier setup for new object-logics;
  1121 
  1122 * Pure: AST translation rules no longer require constant head on LHS;
  1123 
  1124 * Pure: improved name spaces: ambiguous output is qualified; support
  1125 for hiding of names;
  1126 
  1127 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1128 XSYMBOL_HOME; no longer need to do manual configuration in most
  1129 situations;
  1130 
  1131 * system: compression of ML heaps images may now be controlled via -c
  1132 option of isabelle and isatool usedir (currently only observed by
  1133 Poly/ML);
  1134 
  1135 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1136 useful for remote X11);
  1137 
  1138 * system: provide TAGS file for Isabelle sources;
  1139 
  1140 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1141 order;
  1142 
  1143 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1144 timing flag supersedes proof_timing and Toplevel.trace;
  1145 
  1146 * ML: new combinators |>> and |>>> for incremental transformations
  1147 with secondary results (e.g. certain theory extensions):
  1148 
  1149 * ML: PureThy.add_defs gets additional argument to indicate potential
  1150 overloading (usually false);
  1151 
  1152 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1153 results;
  1154 
  1155 
  1156 
  1157 New in Isabelle99 (October 1999)
  1158 --------------------------------
  1159 
  1160 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1161 
  1162 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1163 are no longer simplified.  (This allows the simplifier to unfold recursive
  1164 functional programs.)  To restore the old behaviour, declare
  1165 
  1166     Delcongs [if_weak_cong];
  1167 
  1168 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1169 complement;
  1170 
  1171 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1172 
  1173 * HOL/datatype: mutual_induct_tac no longer exists --
  1174   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1175 
  1176 * HOL/typedef: fixed type inference for representing set; type
  1177 arguments now have to occur explicitly on the rhs as type constraints;
  1178 
  1179 * ZF: The con_defs part of an inductive definition may no longer refer
  1180 to constants declared in the same theory;
  1181 
  1182 * HOL, ZF: the function mk_cases, generated by the inductive
  1183 definition package, has lost an argument.  To simplify its result, it
  1184 uses the default simpset instead of a supplied list of theorems.
  1185 
  1186 * HOL/List: the constructors of type list are now Nil and Cons;
  1187 
  1188 * Simplifier: the type of the infix ML functions
  1189         setSSolver addSSolver setSolver addSolver
  1190 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1191 for packaging solvers. A solver is created via
  1192         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1193 where the string argument is only a comment.
  1194 
  1195 
  1196 *** Proof tools ***
  1197 
  1198 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1199 decision procedure for linear arithmetic. Currently it is used for
  1200 types `nat', `int', and `real' in HOL (see below); it can, should and
  1201 will be instantiated for other types and logics as well.
  1202 
  1203 * The simplifier now accepts rewrite rules with flexible heads, eg
  1204      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1205   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1206   matching.
  1207 
  1208 
  1209 *** General ***
  1210 
  1211 * New Isabelle/Isar subsystem provides an alternative to traditional
  1212 tactical theorem proving; together with the ProofGeneral/isar user
  1213 interface it offers an interactive environment for developing human
  1214 readable proof documents (Isar == Intelligible semi-automated
  1215 reasoning); for further information see isatool doc isar-ref,
  1216 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1217 
  1218 * improved and simplified presentation of theories: better HTML markup
  1219 (including colors), graph views in several sizes; isatool usedir now
  1220 provides a proper interface for user theories (via -P option); actual
  1221 document preparation based on (PDF)LaTeX is available as well (for
  1222 new-style theories only); see isatool doc system for more information;
  1223 
  1224 * native support for Proof General, both for classic Isabelle and
  1225 Isabelle/Isar;
  1226 
  1227 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1228 using the graph browser tool;
  1229 
  1230 * Isabelle manuals now also available as PDF;
  1231 
  1232 * theory loader rewritten from scratch (may not be fully
  1233 bug-compatible); old loadpath variable has been replaced by show_path,
  1234 add_path, del_path, reset_path functions; new operations such as
  1235 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1236 isatool doc ref);
  1237 
  1238 * improved isatool install: option -k creates KDE application icon,
  1239 option -p DIR installs standalone binaries;
  1240 
  1241 * added ML_PLATFORM setting (useful for cross-platform installations);
  1242 more robust handling of platform specific ML images for SML/NJ;
  1243 
  1244 * the settings environment is now statically scoped, i.e. it is never
  1245 created again in sub-processes invoked from isabelle, isatool, or
  1246 Isabelle;
  1247 
  1248 * path element specification '~~' refers to '$ISABELLE_HOME';
  1249 
  1250 * in locales, the "assumes" and "defines" parts may be omitted if
  1251 empty;
  1252 
  1253 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1254 long arrows);
  1255 
  1256 * new print_mode "HTML";
  1257 
  1258 * new flag show_tags controls display of tags of theorems (which are
  1259 basically just comments that may be attached by some tools);
  1260 
  1261 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1262 mode and goal output format:
  1263 
  1264 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1265 244c244
  1266 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1267 ---
  1268 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1269 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1270 181c181
  1271 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1272 ---
  1273 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1274 
  1275 * function bind_thms stores lists of theorems (cf. bind_thm);
  1276 
  1277 * new shorthand tactics ftac, eatac, datac, fatac;
  1278 
  1279 * qed (and friends) now accept "" as result name; in that case the
  1280 theorem is not stored, but proper checks and presentation of the
  1281 result still apply;
  1282 
  1283 * theorem database now also indexes constants "Trueprop", "all",
  1284 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1285 
  1286 
  1287 *** HOL ***
  1288 
  1289 ** HOL arithmetic **
  1290 
  1291 * There are now decision procedures for linear arithmetic over nat and
  1292 int:
  1293 
  1294 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1295 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1296 are treated as atomic; subformulae not involving type `nat' or `int'
  1297 are ignored; quantified subformulae are ignored unless they are
  1298 positive universal or negative existential. The tactic has to be
  1299 invoked by hand and can be a little bit slow. In particular, the
  1300 running time is exponential in the number of occurrences of `min' and
  1301 `max', and `-' on `nat'.
  1302 
  1303 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1304 (negated) (in)equalities among the premises and the conclusion into
  1305 account (i.e. no compound formulae) and does not know about `min' and
  1306 `max', and `-' on `nat'. It is fast and is used automatically by the
  1307 simplifier.
  1308 
  1309 NB: At the moment, these decision procedures do not cope with mixed
  1310 nat/int formulae where the two parts interact, such as `m < n ==>
  1311 int(m) < int(n)'.
  1312 
  1313 * HOL/Numeral provides a generic theory of numerals (encoded
  1314 efficiently as bit strings); setup for types nat/int/real is in place;
  1315 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1316 int, existing theories and proof scripts may require a few additional
  1317 type constraints;
  1318 
  1319 * integer division and remainder can now be performed on constant
  1320 arguments;
  1321 
  1322 * many properties of integer multiplication, division and remainder
  1323 are now available;
  1324 
  1325 * An interface to the Stanford Validity Checker (SVC) is available through the
  1326 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1327 are proved automatically.  SVC must be installed separately, and its results
  1328 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1329 invocation of the underlying oracle).  For SVC see
  1330   http://verify.stanford.edu/SVC
  1331 
  1332 * IsaMakefile: the HOL-Real target now builds an actual image;
  1333 
  1334 
  1335 ** HOL misc **
  1336 
  1337 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1338 (in Isabelle/Isar) -- by Gertrud Bauer;
  1339 
  1340 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1341 analysis for assembly languages with subtypes;
  1342 
  1343 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1344 -- avoids syntactic ambiguities and treats state, transition, and
  1345 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1346 changed syntax and (many) tactics;
  1347 
  1348 * HOL/inductive: Now also handles more general introduction rules such
  1349   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1350   theorems are now maintained within the theory (maintained via the
  1351   "mono" attribute);
  1352 
  1353 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1354   (using function types) such as
  1355 
  1356   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1357 
  1358 * HOL/record: record_simproc (part of the default simpset) takes care
  1359 of selectors applied to updated records; record_split_tac is no longer
  1360 part of the default claset; update_defs may now be removed from the
  1361 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1362 
  1363   claset_ref () := claset() addSWrapper record_split_wrapper;
  1364   Delsimprocs [record_simproc]
  1365 
  1366 * HOL/typedef: fixed type inference for representing set; type
  1367 arguments now have to occur explicitly on the rhs as type constraints;
  1368 
  1369 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1370 names rather than an ML expression;
  1371 
  1372 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1373 supplied later.  Program schemes can be defined, such as
  1374     "While B C s = (if B s then While B C (C s) else s)"
  1375 where the well-founded relation can be chosen after B and C have been given.
  1376 
  1377 * HOL/List: the constructors of type list are now Nil and Cons;
  1378 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1379 course, ML tools referring to List.list.op # etc. have to be adapted;
  1380 
  1381 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1382 disabled by default; run isabelle with option -m HOL to get back to
  1383 the original Gordon/HOL-style output;
  1384 
  1385 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1386 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1387 
  1388 * HOL basic syntax simplified (more orthogonal): all variants of
  1389 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1390 Eps operator is provided as well: "SOME x. P[x]";
  1391 
  1392 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1393 
  1394 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1395 thus available for user theories;
  1396 
  1397 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1398 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1399 time;
  1400 
  1401 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1402 several times and then mp;
  1403 
  1404 
  1405 *** LK ***
  1406 
  1407 * the notation <<...>> is now available as a notation for sequences of
  1408 formulas;
  1409 
  1410 * the simplifier is now installed
  1411 
  1412 * the axiom system has been generalized (thanks to Soren Heilmann)
  1413 
  1414 * the classical reasoner now has a default rule database
  1415 
  1416 
  1417 *** ZF ***
  1418 
  1419 * new primrec section allows primitive recursive functions to be given
  1420 directly (as in HOL) over datatypes and the natural numbers;
  1421 
  1422 * new tactics induct_tac and exhaust_tac for induction (or case
  1423 analysis) over datatypes and the natural numbers;
  1424 
  1425 * the datatype declaration of type T now defines the recursor T_rec;
  1426 
  1427 * simplification automatically does freeness reasoning for datatype
  1428 constructors;
  1429 
  1430 * automatic type-inference, with AddTCs command to insert new
  1431 type-checking rules;
  1432 
  1433 * datatype introduction rules are now added as Safe Introduction rules
  1434 to the claset;
  1435 
  1436 * the syntax "if P then x else y" is now available in addition to
  1437 if(P,x,y);
  1438 
  1439 
  1440 *** Internal programming interfaces ***
  1441 
  1442 * tuned simplifier trace output; new flag debug_simp;
  1443 
  1444 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1445 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1446 
  1447 * AxClass.axclass_tac lost the theory argument;
  1448 
  1449 * tuned current_goals_markers semantics: begin / end goal avoids
  1450 printing empty lines;
  1451 
  1452 * removed prs and prs_fn hook, which was broken because it did not
  1453 include \n in its semantics, forcing writeln to add one
  1454 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1455 string -> unit if you really want to output text without newline;
  1456 
  1457 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1458 plain output, interface builders may have to enable 'isabelle_font'
  1459 mode to get Isabelle font glyphs as before;
  1460 
  1461 * refined token_translation interface; INCOMPATIBILITY: output length
  1462 now of type real instead of int;
  1463 
  1464 * theory loader actions may be traced via new ThyInfo.add_hook
  1465 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1466 your own database of information attached to *whole* theories -- as
  1467 opposed to intra-theory data slots offered via TheoryDataFun;
  1468 
  1469 * proper handling of dangling sort hypotheses (at last!);
  1470 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1471 extra sort hypotheses that can be witnessed from the type signature;
  1472 the force_strip_shyps flag is gone, any remaining shyps are simply
  1473 left in the theorem (with a warning issued by strip_shyps_warning);
  1474 
  1475 
  1476 
  1477 New in Isabelle98-1 (October 1998)
  1478 ----------------------------------
  1479 
  1480 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1481 
  1482 * several changes of automated proof tools;
  1483 
  1484 * HOL: major changes to the inductive and datatype packages, including
  1485 some minor incompatibilities of theory syntax;
  1486 
  1487 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1488 called `inj_on';
  1489 
  1490 * HOL: removed duplicate thms in Arith:
  1491   less_imp_add_less  should be replaced by  trans_less_add1
  1492   le_imp_add_le      should be replaced by  trans_le_add1
  1493 
  1494 * HOL: unary minus is now overloaded (new type constraints may be
  1495 required);
  1496 
  1497 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1498 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1499 now taken as an integer constant.
  1500 
  1501 * Pure: ML function 'theory_of' renamed to 'theory';
  1502 
  1503 
  1504 *** Proof tools ***
  1505 
  1506 * Simplifier:
  1507   1. Asm_full_simp_tac is now more aggressive.
  1508      1. It will sometimes reorient premises if that increases their power to
  1509         simplify.
  1510      2. It does no longer proceed strictly from left to right but may also
  1511         rotate premises to achieve further simplification.
  1512      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1513      old Asm_full_simp_tac in that it does not rotate premises.
  1514   2. The simplifier now knows a little bit about nat-arithmetic.
  1515 
  1516 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1517 allows for selected deletion of wrappers, by introduction of names for
  1518 wrapper functionals.  This implies that addbefore, addSbefore,
  1519 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1520 and that adding two tactics with the same name overwrites the first
  1521 one (emitting a warning).
  1522   type wrapper = (int -> tactic) -> (int -> tactic)
  1523   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1524   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1525   delWrapper, delSWrapper: claset *  string            -> claset
  1526   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1527 
  1528 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1529 semantics; addbefore now affects only the unsafe part of step_tac
  1530 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1531 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1532 by Force_tac;
  1533 
  1534 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1535 compWrapper; added safe wrapper (and access functions for it);
  1536 
  1537 * HOL/split_all_tac is now much faster and fails if there is nothing
  1538 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1539 and the names of the automatically generated variables have changed.
  1540 split_all_tac has moved within claset() from unsafe wrappers to safe
  1541 wrappers, which means that !!-bound variables are split much more
  1542 aggressively, and safe_tac and clarify_tac now split such variables.
  1543 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1544 Note: the same holds for record_split_tac, which does the job of
  1545 split_all_tac for record fields.
  1546 
  1547 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1548 permanently to the default simpset using Addsplits just like
  1549 Addsimps. They can be removed via Delsplits just like
  1550 Delsimps. Lower-case versions are also available.
  1551 
  1552 * HOL/Simplifier: The rule split_if is now part of the default
  1553 simpset. This means that the simplifier will eliminate all occurrences
  1554 of if-then-else in the conclusion of a goal. To prevent this, you can
  1555 either remove split_if completely from the default simpset by
  1556 `Delsplits [split_if]' or remove it in a specific call of the
  1557 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1558 other case splitting rules to/from the default simpset: every datatype
  1559 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1560 t is the name of the datatype).
  1561 
  1562 * Classical reasoner / Simplifier combination: new force_tac (and
  1563 derivatives Force_tac, force) combines rewriting and classical
  1564 reasoning (and whatever other tools) similarly to auto_tac, but is
  1565 aimed to solve the given subgoal completely.
  1566 
  1567 
  1568 *** General ***
  1569 
  1570 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1571 and `goalw': the theory is no longer needed as an explicit argument -
  1572 the current theory context is used; assumptions are no longer returned
  1573 at the ML-level unless one of them starts with ==> or !!; it is
  1574 recommended to convert to these new commands using isatool fixgoal
  1575 (backup your sources first!);
  1576 
  1577 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1578 the current theory context, and 'theory' to lookup stored theories;
  1579 
  1580 * new theory section 'locale' for declaring constants, assumptions and
  1581 definitions that have local scope;
  1582 
  1583 * new theory section 'nonterminals' for purely syntactic types;
  1584 
  1585 * new theory section 'setup' for generic ML setup functions
  1586 (e.g. package initialization);
  1587 
  1588 * the distribution now includes Isabelle icons: see
  1589 lib/logo/isabelle-{small,tiny}.xpm;
  1590 
  1591 * isatool install - install binaries with absolute references to
  1592 ISABELLE_HOME/bin;
  1593 
  1594 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1595 
  1596 * print mode 'emacs' reserved for Isamode;
  1597 
  1598 * support multiple print (ast) translations per constant name;
  1599 
  1600 * theorems involving oracles are now printed with a suffixed [!];
  1601 
  1602 
  1603 *** HOL ***
  1604 
  1605 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1606 
  1607 * HOL/inductive package reorganized and improved: now supports mutual
  1608 definitions such as
  1609 
  1610   inductive EVEN ODD
  1611     intrs
  1612       null "0 : EVEN"
  1613       oddI "n : EVEN ==> Suc n : ODD"
  1614       evenI "n : ODD ==> Suc n : EVEN"
  1615 
  1616 new theorem list "elims" contains an elimination rule for each of the
  1617 recursive sets; inductive definitions now handle disjunctive premises
  1618 correctly (also ZF);
  1619 
  1620 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1621 "mutual_induct" no longer exists - the induction rule is always
  1622 contained in "induct";
  1623 
  1624 
  1625 * HOL/datatype package re-implemented and greatly improved: now
  1626 supports mutually recursive datatypes such as
  1627 
  1628   datatype
  1629     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1630             | SUM ('a aexp) ('a aexp)
  1631             | DIFF ('a aexp) ('a aexp)
  1632             | NUM 'a
  1633   and
  1634     'a bexp = LESS ('a aexp) ('a aexp)
  1635             | AND ('a bexp) ('a bexp)
  1636             | OR ('a bexp) ('a bexp)
  1637 
  1638 as well as indirectly recursive datatypes such as
  1639 
  1640   datatype
  1641     ('a, 'b) term = Var 'a
  1642                   | App 'b ((('a, 'b) term) list)
  1643 
  1644 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1645 induction on mutually / indirectly recursive datatypes.
  1646 
  1647 Primrec equations are now stored in theory and can be accessed via
  1648 <function_name>.simps.
  1649 
  1650 INCOMPATIBILITIES:
  1651 
  1652   - Theories using datatypes must now have theory Datatype as an
  1653     ancestor.
  1654   - The specific <typename>.induct_tac no longer exists - use the
  1655     generic induct_tac instead.
  1656   - natE has been renamed to nat.exhaust - use exhaust_tac
  1657     instead of res_inst_tac ... natE. Note that the variable
  1658     names in nat.exhaust differ from the names in natE, this
  1659     may cause some "fragile" proofs to fail.
  1660   - The theorems split_<typename>_case and split_<typename>_case_asm
  1661     have been renamed to <typename>.split and <typename>.split_asm.
  1662   - Since default sorts of type variables are now handled correctly,
  1663     some datatype definitions may have to be annotated with explicit
  1664     sort constraints.
  1665   - Primrec definitions no longer require function name and type
  1666     of recursive argument.
  1667 
  1668 Consider using isatool fixdatatype to adapt your theories and proof
  1669 scripts to the new package (backup your sources first!).
  1670 
  1671 
  1672 * HOL/record package: considerably improved implementation; now
  1673 includes concrete syntax for record types, terms, updates; theorems
  1674 for surjective pairing and splitting !!-bound record variables; proof
  1675 support is as follows:
  1676 
  1677   1) standard conversions (selectors or updates applied to record
  1678 constructor terms) are part of the standard simpset;
  1679 
  1680   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1681 made part of standard simpset and claset via addIffs;
  1682 
  1683   3) a tactic for record field splitting (record_split_tac) is part of
  1684 the standard claset (addSWrapper);
  1685 
  1686 To get a better idea about these rules you may retrieve them via
  1687 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1688 the name of your record type.
  1689 
  1690 The split tactic 3) conceptually simplifies by the following rule:
  1691 
  1692   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1693 
  1694 Thus any record variable that is bound by meta-all will automatically
  1695 blow up into some record constructor term, consequently the
  1696 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1697 solve record problems automatically.
  1698 
  1699 
  1700 * reorganized the main HOL image: HOL/Integ and String loaded by
  1701 default; theory Main includes everything;
  1702 
  1703 * automatic simplification of integer sums and comparisons, using cancellation;
  1704 
  1705 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1706 
  1707 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1708 
  1709 * many new identities for unions, intersections, set difference, etc.;
  1710 
  1711 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1712 called split_if, split_split, split_sum_case and split_nat_case (to go
  1713 with add/delsplits);
  1714 
  1715 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1716 (?x::unit) = (); this is made part of the default simpset, which COULD
  1717 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1718 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1719 unit_abs_eta_conv is added in order to counter the effect of
  1720 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1721 %u.f();
  1722 
  1723 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1724 makes more sense);
  1725 
  1726 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1727   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1728   disjointness reasoning but breaking a few old proofs.
  1729 
  1730 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1731 to 'converse' from 'inverse' (for compatibility with ZF and some
  1732 literature);
  1733 
  1734 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1735 the well-founded relation;
  1736 
  1737 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1738     Compl A.  The "Compl" syntax remains available as input syntax for this
  1739     release ONLY.
  1740 
  1741 * HOL/Update: new theory of function updates:
  1742     f(a:=b) == %x. if x=a then b else f x
  1743 may also be iterated as in f(a:=b,c:=d,...);
  1744 
  1745 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1746 
  1747 * HOL/List:
  1748   - new function list_update written xs[i:=v] that updates the i-th
  1749     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1750   - new function `upt' written [i..j(] which generates the list
  1751     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1752     bound write [i..j], which is a shorthand for [i..j+1(].
  1753   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1754 
  1755 * HOL/Arith:
  1756   - removed 'pred' (predecessor) function;
  1757   - generalized some theorems about n-1;
  1758   - many new laws about "div" and "mod";
  1759   - new laws about greatest common divisors (see theory ex/Primes);
  1760 
  1761 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1762 instead of "inverse";
  1763 
  1764 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1765   of the multiset ordering;
  1766 
  1767 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1768   (not included by default);
  1769 
  1770 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1771 
  1772 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1773   programs, i.e. different program variables may have different types.
  1774 
  1775 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1776   [previously, this check worked only if the rewrite rule was unconditional]
  1777   Now rew can involve either definitions or equalities (either == or =).
  1778 
  1779 
  1780 *** ZF ***
  1781 
  1782 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1783   only the theorems proved on ZF.ML;
  1784 
  1785 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1786   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1787   disjointness reasoning but breaking a few old proofs.
  1788 
  1789 * ZF/Update: new theory of function updates
  1790     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1791   may also be iterated as in f(a:=b,c:=d,...);
  1792 
  1793 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1794 
  1795 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1796   [previously, this check worked only if the rewrite rule was unconditional]
  1797   Now rew can involve either definitions or equalities (either == or =).
  1798 
  1799 * case_tac provided for compatibility with HOL
  1800     (like the old excluded_middle_tac, but with subgoals swapped)
  1801 
  1802 
  1803 *** Internal programming interfaces ***
  1804 
  1805 * Pure: several new basic modules made available for general use, see
  1806 also src/Pure/README;
  1807 
  1808 * improved the theory data mechanism to support encapsulation (data
  1809 kind name replaced by private Object.kind, acting as authorization
  1810 key); new type-safe user interface via functor TheoryDataFun; generic
  1811 print_data function becomes basically useless;
  1812 
  1813 * removed global_names compatibility flag -- all theory declarations
  1814 are qualified by default;
  1815 
  1816 * module Pure/Syntax now offers quote / antiquote translation
  1817 functions (useful for Hoare logic etc. with implicit dependencies);
  1818 see HOL/ex/Antiquote for an example use;
  1819 
  1820 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1821 cterm -> thm;
  1822 
  1823 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1824 subgoal;
  1825 
  1826 * Display.print_goals function moved to Locale.print_goals;
  1827 
  1828 * standard print function for goals supports current_goals_markers
  1829 variable for marking begin of proof, end of proof, start of goal; the
  1830 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1831 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1832 for example;
  1833 
  1834 
  1835 
  1836 New in Isabelle98 (January 1998)
  1837 --------------------------------
  1838 
  1839 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1840 
  1841 * changed lexical syntax of terms / types: dots made part of long
  1842 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1843 
  1844 * simpset (and claset) reference variable replaced by functions
  1845 simpset / simpset_ref;
  1846 
  1847 * no longer supports theory aliases (via merge) and non-trivial
  1848 implicit merge of thms' signatures;
  1849 
  1850 * most internal names of constants changed due to qualified names;
  1851 
  1852 * changed Pure/Sequence interface (see Pure/seq.ML);
  1853 
  1854 
  1855 *** General Changes ***
  1856 
  1857 * hierachically structured name spaces (for consts, types, axms, thms
  1858 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1859 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1860 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1861 long_names for fully qualified output names; NOTE: ML programs
  1862 (special tactics, packages etc.) referring to internal names may have
  1863 to be adapted to cope with fully qualified names; in case of severe
  1864 backward campatibility problems try setting 'global_names' at compile
  1865 time to have enrything declared within a flat name space; one may also
  1866 fine tune name declarations in theories via the 'global' and 'local'
  1867 section;
  1868 
  1869 * reimplemented the implicit simpset and claset using the new anytype
  1870 data filed in signatures; references simpset:simpset ref etc. are
  1871 replaced by functions simpset:unit->simpset and
  1872 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1873 to patch your ML files accordingly;
  1874 
  1875 * HTML output now includes theory graph data for display with Java
  1876 applet or isatool browser; data generated automatically via isatool
  1877 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1878 
  1879 * defs may now be conditional; improved rewrite_goals_tac to handle
  1880 conditional equations;
  1881 
  1882 * defs now admits additional type arguments, using TYPE('a) syntax;
  1883 
  1884 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1885 creates a new theory node; implicit merge of thms' signatures is
  1886 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1887 transfer:theory->thm->thm in (rare) cases;
  1888 
  1889 * improved handling of draft signatures / theories; draft thms (and
  1890 ctyps, cterms) are automatically promoted to real ones;
  1891 
  1892 * slightly changed interfaces for oracles: admit many per theory, named
  1893 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1894 
  1895 * print_goals: optional output of const types (set show_consts and
  1896 show_types);
  1897 
  1898 * improved output of warnings (###) and errors (***);
  1899 
  1900 * subgoal_tac displays a warning if the new subgoal has type variables;
  1901 
  1902 * removed old README and Makefiles;
  1903 
  1904 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1905 
  1906 * removed obsolete init_pps and init_database;
  1907 
  1908 * deleted the obsolete tactical STATE, which was declared by
  1909     fun STATE tacfun st = tacfun st st;
  1910 
  1911 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1912 (which abbreviates $HOME);
  1913 
  1914 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1915 use isatool fixseq to adapt your ML programs (this works for fully
  1916 qualified references to the Sequence structure only!);
  1917 
  1918 * use_thy no longer requires writable current directory; it always
  1919 reloads .ML *and* .thy file, if either one is out of date;
  1920 
  1921 
  1922 *** Classical Reasoner ***
  1923 
  1924 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1925 tactics that use classical reasoning to simplify a subgoal without
  1926 splitting it into several subgoals;
  1927 
  1928 * Safe_tac: like safe_tac but uses the default claset;
  1929 
  1930 
  1931 *** Simplifier ***
  1932 
  1933 * added simplification meta rules:
  1934     (asm_)(full_)simplify: simpset -> thm -> thm;
  1935 
  1936 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1937 logics (again);
  1938 
  1939 * added prems argument to simplification procedures;
  1940 
  1941 * HOL, FOL, ZF: added infix function `addsplits':
  1942   instead of `<simpset> setloop (split_tac <thms>)'
  1943   you can simply write `<simpset> addsplits <thms>'
  1944 
  1945 
  1946 *** Syntax ***
  1947 
  1948 * TYPE('a) syntax for type reflection terms;
  1949 
  1950 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1951 
  1952 * pretty printer: changed order of mixfix annotation preference (again!);
  1953 
  1954 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1955 
  1956 
  1957 *** HOL ***
  1958 
  1959 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1960   with `addloop' of the simplifier to faciliate case splitting in premises.
  1961 
  1962 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1963 
  1964 * HOL/Auth: new protocol proofs including some for the Internet
  1965   protocol TLS;
  1966 
  1967 * HOL/Map: new theory of `maps' a la VDM;
  1968 
  1969 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1970 cancelling out common nat summands from =, <, <= (in)equalities, or
  1971 differences; simplification procedures nat_cancel_factor for
  1972 cancelling common factor from =, <, <= (in)equalities over natural
  1973 sums; nat_cancel contains both kinds of procedures, it is installed by
  1974 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1975 
  1976 * HOL/simplifier: terms of the form
  1977   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1978   are rewritten to
  1979   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1980   and those of the form
  1981   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1982   are rewritten to
  1983   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1984 
  1985 * HOL/datatype
  1986   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1987 
  1988   P(t_case f1 ... fn x) =
  1989      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1990         ...
  1991        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1992      )
  1993 
  1994   and a theorem `split_t_case_asm' of the form
  1995 
  1996   P(t_case f1 ... fn x) =
  1997     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1998         ...
  1999        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2000      )
  2001   which can be added to a simpset via `addsplits'. The existing theorems
  2002   expand_list_case and expand_option_case have been renamed to
  2003   split_list_case and split_option_case.
  2004 
  2005 * HOL/Arithmetic:
  2006   - `pred n' is automatically converted to `n-1'.
  2007     Users are strongly encouraged not to use `pred' any longer,
  2008     because it will disappear altogether at some point.
  2009   - Users are strongly encouraged to write "0 < n" rather than
  2010     "n ~= 0". Theorems and proof tools have been modified towards this
  2011     `standard'.
  2012 
  2013 * HOL/Lists:
  2014   the function "set_of_list" has been renamed "set" (and its theorems too);
  2015   the function "nth" now takes its arguments in the reverse order and
  2016   has acquired the infix notation "!" as in "xs!n".
  2017 
  2018 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2019 
  2020 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2021   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2022 
  2023 * HOL/record: extensible records with schematic structural subtyping
  2024 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2025 still lacks various theorems and concrete record syntax;
  2026 
  2027 
  2028 *** HOLCF ***
  2029 
  2030 * removed "axioms" and "generated by" sections;
  2031 
  2032 * replaced "ops" section by extended "consts" section, which is capable of
  2033   handling the continuous function space "->" directly;
  2034 
  2035 * domain package:
  2036   . proves theorems immediately and stores them in the theory,
  2037   . creates hierachical name space,
  2038   . now uses normal mixfix annotations (instead of cinfix...),
  2039   . minor changes to some names and values (for consistency),
  2040   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2041   . separator between mutual domain defs: changed "," to "and",
  2042   . improved handling of sort constraints;  now they have to
  2043     appear on the left-hand side of the equations only;
  2044 
  2045 * fixed LAM <x,y,zs>.b syntax;
  2046 
  2047 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2048 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2049 
  2050 
  2051 *** FOL and ZF ***
  2052 
  2053 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2054   with `addloop' of the simplifier to faciliate case splitting in premises.
  2055 
  2056 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2057 in HOL, they strip ALL and --> from proved theorems;
  2058 
  2059 
  2060 
  2061 New in Isabelle94-8 (May 1997)
  2062 ------------------------------
  2063 
  2064 *** General Changes ***
  2065 
  2066 * new utilities to build / run / maintain Isabelle etc. (in parts
  2067 still somewhat experimental); old Makefiles etc. still functional;
  2068 
  2069 * new 'Isabelle System Manual';
  2070 
  2071 * INSTALL text, together with ./configure and ./build scripts;
  2072 
  2073 * reimplemented type inference for greater efficiency, better error
  2074 messages and clean internal interface;
  2075 
  2076 * prlim command for dealing with lots of subgoals (an easier way of
  2077 setting goals_limit);
  2078 
  2079 
  2080 *** Syntax ***
  2081 
  2082 * supports alternative (named) syntax tables (parser and pretty
  2083 printer); internal interface is provided by add_modesyntax(_i);
  2084 
  2085 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2086 be used in conjunction with the Isabelle symbol font; uses the
  2087 "symbols" syntax table;
  2088 
  2089 * added token_translation interface (may translate name tokens in
  2090 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2091 the current print_mode); IMPORTANT: user print translation functions
  2092 are responsible for marking newly introduced bounds
  2093 (Syntax.mark_boundT);
  2094 
  2095 * token translations for modes "xterm" and "xterm_color" that display
  2096 names in bold, underline etc. or colors (which requires a color
  2097 version of xterm);
  2098 
  2099 * infixes may now be declared with names independent of their syntax;
  2100 
  2101 * added typed_print_translation (like print_translation, but may
  2102 access type of constant);
  2103 
  2104 
  2105 *** Classical Reasoner ***
  2106 
  2107 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2108 some limitations.  Blast_tac...
  2109   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2110   + ignores elimination rules that don't have the correct format
  2111         (the conclusion MUST be a formula variable)
  2112   + ignores types, which can make HOL proofs fail
  2113   + rules must not require higher-order unification, e.g. apply_type in ZF
  2114     [message "Function Var's argument not a bound variable" relates to this]
  2115   + its proof strategy is more general but can actually be slower
  2116 
  2117 * substitution with equality assumptions no longer permutes other
  2118 assumptions;
  2119 
  2120 * minor changes in semantics of addafter (now called addaltern); renamed
  2121 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2122 (and access functions for it);
  2123 
  2124 * improved combination of classical reasoner and simplifier:
  2125   + functions for handling clasimpsets
  2126   + improvement of addss: now the simplifier is called _after_ the
  2127     safe steps.
  2128   + safe variant of addss called addSss: uses safe simplifications
  2129     _during_ the safe steps. It is more complete as it allows multiple
  2130     instantiations of unknowns (e.g. with slow_tac).
  2131 
  2132 *** Simplifier ***
  2133 
  2134 * added interface for simplification procedures (functions that
  2135 produce *proven* rewrite rules on the fly, depending on current
  2136 redex);
  2137 
  2138 * ordering on terms as parameter (used for ordered rewriting);
  2139 
  2140 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2141 
  2142 * the solver is now split into a safe and an unsafe part.
  2143 This should be invisible for the normal user, except that the
  2144 functions setsolver and addsolver have been renamed to setSolver and
  2145 addSolver; added safe_asm_full_simp_tac;
  2146 
  2147 
  2148 *** HOL ***
  2149 
  2150 * a generic induction tactic `induct_tac' which works for all datatypes and
  2151 also for type `nat';
  2152 
  2153 * a generic case distinction tactic `exhaust_tac' which works for all
  2154 datatypes and also for type `nat';
  2155 
  2156 * each datatype comes with a function `size';
  2157 
  2158 * patterns in case expressions allow tuple patterns as arguments to
  2159 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2160 
  2161 * primrec now also works with type nat;
  2162 
  2163 * recdef: a new declaration form, allows general recursive functions to be
  2164 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2165 
  2166 * the constant for negation has been renamed from "not" to "Not" to
  2167 harmonize with FOL, ZF, LK, etc.;
  2168 
  2169 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2170 infinite lists;
  2171 
  2172 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2173 
  2174 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2175 problems in commutative rings, using axiomatic type classes for + and *;
  2176 
  2177 * more examples in HOL/MiniML and HOL/Auth;
  2178 
  2179 * more default rewrite rules for quantifiers, union/intersection;
  2180 
  2181 * a new constant `arbitrary == @x.False';
  2182 
  2183 * HOLCF/IOA replaces old HOL/IOA;
  2184 
  2185 * HOLCF changes: derived all rules and arities
  2186   + axiomatic type classes instead of classes
  2187   + typedef instead of faking type definitions
  2188   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2189   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2190   + eliminated the types void, one, tr
  2191   + use unit lift and bool lift (with translations) instead of one and tr
  2192   + eliminated blift from Lift3.thy (use Def instead of blift)
  2193   all eliminated rules are derived as theorems --> no visible changes ;
  2194 
  2195 
  2196 *** ZF ***
  2197 
  2198 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2199 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2200 as ZF_cs addSIs [equalityI];
  2201 
  2202 
  2203 
  2204 New in Isabelle94-7 (November 96)
  2205 ---------------------------------
  2206 
  2207 * allowing negative levels (as offsets) in prlev and choplev;
  2208 
  2209 * super-linear speedup for large simplifications;
  2210 
  2211 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2212 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2213 FAIL); can suppress it using the command Delsimps (ex_simps @
  2214 all_simps); De Morgan laws are also now included, by default;
  2215 
  2216 * improved printing of ==>  :  ~:
  2217 
  2218 * new object-logic "Sequents" adds linear logic, while replacing LK
  2219 and Modal (thanks to Sara Kalvala);
  2220 
  2221 * HOL/Auth: correctness proofs for authentication protocols;
  2222 
  2223 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2224 examples on HOL/Auth);
  2225 
  2226 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2227 the rewriter and classical reasoner simultaneously;
  2228 
  2229 * function uresult no longer returns theorems in "standard" format;
  2230 regain previous version by: val uresult = standard o uresult;
  2231 
  2232 
  2233 
  2234 New in Isabelle94-6
  2235 -------------------
  2236 
  2237 * oracles -- these establish an interface between Isabelle and trusted
  2238 external reasoners, which may deliver results as theorems;
  2239 
  2240 * proof objects (in particular record all uses of oracles);
  2241 
  2242 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2243 
  2244 * "constdefs" section in theory files;
  2245 
  2246 * "primrec" section (HOL) no longer requires names;
  2247 
  2248 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2249 
  2250 
  2251 
  2252 New in Isabelle94-5
  2253 -------------------
  2254 
  2255 * reduced space requirements;
  2256 
  2257 * automatic HTML generation from theories;
  2258 
  2259 * theory files no longer require "..." (quotes) around most types;
  2260 
  2261 * new examples, including two proofs of the Church-Rosser theorem;
  2262 
  2263 * non-curried (1994) version of HOL is no longer distributed;
  2264 
  2265 
  2266 
  2267 New in Isabelle94-4
  2268 -------------------
  2269 
  2270 * greatly reduced space requirements;
  2271 
  2272 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2273 
  2274 * searchable theorem database (see the section "Retrieving theorems" on
  2275 page 8 of the Reference Manual);
  2276 
  2277 * new examples, including Grabczewski's monumental case study of the
  2278 Axiom of Choice;
  2279 
  2280 * The previous version of HOL renamed to Old_HOL;
  2281 
  2282 * The new version of HOL (previously called CHOL) uses a curried syntax
  2283 for functions.  Application looks like f a b instead of f(a,b);
  2284 
  2285 * Mutually recursive inductive definitions finally work in HOL;
  2286 
  2287 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2288 translates to the operator "split";
  2289 
  2290 
  2291 
  2292 New in Isabelle94-3
  2293 -------------------
  2294 
  2295 * new infix operator, addss, allowing the classical reasoner to
  2296 perform simplification at each step of its search.  Example:
  2297         fast_tac (cs addss ss)
  2298 
  2299 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2300 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2301 look like (a,b) instead of <a,b>;
  2302 
  2303 * PLEASE NOTE: CHOL will eventually replace HOL!
  2304 
  2305 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2306 It translates to the operator "split".  A new theory of integers is available;
  2307 
  2308 * In ZF, integer numerals now denote two's-complement binary integers.
  2309 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2310 
  2311 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2312 of the Axiom of Choice;
  2313 
  2314 
  2315 
  2316 New in Isabelle94-2
  2317 -------------------
  2318 
  2319 * Significantly faster resolution;
  2320 
  2321 * the different sections in a .thy file can now be mixed and repeated
  2322 freely;
  2323 
  2324 * Database of theorems for FOL, HOL and ZF.  New
  2325 commands including qed, qed_goal and bind_thm store theorems in the database.
  2326 
  2327 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2328 a given theory (thms_of), or find out what theory a theorem was proved in
  2329 (theory_of_thm);
  2330 
  2331 * Bugs fixed in the inductive definition and datatype packages;
  2332 
  2333 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2334 and HOL_dup_cs obsolete;
  2335 
  2336 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2337 have been removed;
  2338 
  2339 * Simpler definition of function space in ZF;
  2340 
  2341 * new results about cardinal and ordinal arithmetic in ZF;
  2342 
  2343 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2344 types;
  2345 
  2346 
  2347 $Id$