NEWS
author nipkow
Tue Feb 11 11:04:27 2003 +0100 (2003-02-11)
changeset 13815 0832792725db
parent 13781 ecb2df44253e
child 13824 e4d8dea6dfc2
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 method simp (ML: 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     -- simp sometimes diverges where the old version did
    19        not, e.g. invoking simp 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 "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    28        kind of problem.
    29 
    30     -- Tactics combining classical reasoner and simplification (such as auto)
    31        are also affected by this change, because many of them rely on
    32        simp. They may sometimes diverge as well or yield a different numbers
    33        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    34        in case of problems. Sometimes subsequent calls to the classical
    35        reasoner will fail because a preceeding call to the simplifier too
    36        eagerly simplified the goal, e.g. deleted redundant premises.
    37 
    38   - The simplifier trace now shows the names of the applied rewrite rules
    39 
    40 * Pure: New flag for triggering if the overall goal of a proof state should
    41 be printed:
    42    PG menu: Isabelle/Isar -> Settigs -> Show Main Goal
    43 (ML: Proof.show_main_goal).
    44 
    45 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
    46 rules whose conclusion matches subgoal 1:
    47       PG menu: Isabelle/Isar -> Show me -> matching rules
    48 The rules are ordered by how closely they match the subgoal.
    49 In particular, rules that solve a subgoal outright are displayed first
    50 (or rather last, the way they are printed).
    51 (ML: ProofGeneral.print_intros())
    52 
    53 * Pure: New flag trace_unify_fail causes unification to print
    54 diagnostic information (PG: in trace buffer) when it fails. This is
    55 useful for figuring out why single step proofs like rule, erule or
    56 assumption failed.
    57 
    58 * Pure: Locale specifications now produce predicate definitions
    59 according to the body of text (covering assumptions modulo local
    60 definitions); predicate "loc_axioms" covers newly introduced text,
    61 while "loc" is cumulative wrt. all included locale expressions; the
    62 latter view is presented only on export into the global theory
    63 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    64 on the old view without predicates;
    65 
    66 * Pure: predefined locales "var" and "struct" are useful for sharing
    67 parameters (as in CASL, for example); just specify something like
    68 ``var x + var y + struct M'' as import;
    69 
    70 * Pure: improved thms_containing: proper indexing of facts instead of
    71 raw theorems; check validity of results wrt. current name space;
    72 include local facts of proof configuration (also covers active
    73 locales), cover fixed variables in index; may use "_" in term
    74 specification; an optional limit for the number of printed facts may
    75 be given (the default is 40);
    76 
    77 * Pure: disallow duplicate fact bindings within new-style theory files
    78 (batch-mode only);
    79 
    80 * Provers: improved induct method: assumptions introduced by case
    81 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    82 the goal statement); "foo" still refers to all facts collectively;
    83 
    84 * Provers: the function blast.overloaded has been removed: all constants
    85 are regarded as potentially overloaded, which improves robustness in exchange
    86 for slight decrease in efficiency;
    87 
    88 * Provers/linorder: New generic prover for transitivity reasoning over
    89 linear orders.  Note: this prover is not efficient!
    90 
    91 * Isar: preview of problems to finish 'show' now produce an error
    92 rather than just a warning (in interactive mode);
    93 
    94 
    95 *** HOL ***
    96 
    97 * GroupTheory: new, experimental summation operator for abelian groups.
    98 
    99 * New tactic "trans_tac" and method "trans" instantiate
   100 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   101 "<=", "<" and "="). 
   102 
   103 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   104 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   105 
   106 * 'typedef' command has new option "open" to suppress the set
   107 definition;
   108 
   109 * functions Min and Max on finite sets have been introduced (theory
   110 Finite_Set);
   111 
   112 * attribute [symmetric] now works for relations as well; it turns
   113 (x,y) : R^-1 into (y,x) : R, and vice versa;
   114 
   115 * arith(_tac) now produces a counter example if it cannot prove a theorem.
   116   In ProofGeneral the counter example appears in the trace buffer.
   117 
   118 * arith(_tac) does now know about div k and mod k where k is a numeral
   119 of type nat or int. It can solve simple goals like
   120 
   121   "0 < n ==> n div 2 < (n::nat)"
   122 
   123 but fails if divisibility plays a role like in
   124 
   125   "n div 2 + (n+1) div 2 = (n::nat)"
   126 
   127 * simp's arithmetic capabilities have been enhanced a bit: it now
   128 takes ~= in premises into account (by performing a case split);
   129 
   130 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   131 are distributed over a sum of terms;
   132 
   133 * induct over a !!-quantified statement (say !!x1..xn):
   134   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   135 
   136 * GroupTheory: converted to Isar theories, using locales with implicit structures;
   137 
   138 * Real/HahnBanach: updated and adapted to locales;
   139 
   140 
   141 *** ZF ***
   142 
   143 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   144 universe, etc.);
   145 
   146 * Main ZF: many theories converted to new-style format;
   147 
   148 
   149 *** ML ***
   150 
   151 * Pure: Tactic.prove provides sane interface for internal proofs;
   152 omits the infamous "standard" operation, so this is more appropriate
   153 than prove_goalw_cterm in many situations (e.g. in simprocs);
   154 
   155 * Pure: improved error reporting of simprocs;
   156 
   157 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   158 up simprocs;
   159 
   160 
   161 
   162 New in Isabelle2002 (March 2002)
   163 --------------------------------
   164 
   165 *** Document preparation ***
   166 
   167 * greatly simplified document preparation setup, including more
   168 graceful interpretation of isatool usedir -i/-d/-D options, and more
   169 instructive isatool mkdir; users should basically be able to get
   170 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   171 users may run a separate document processing stage manually like this:
   172 "isatool usedir -D output HOL Test && isatool document Test/output";
   173 
   174 * theory dependency graph may now be incorporated into documents;
   175 isatool usedir -g true will produce session_graph.eps/.pdf for use
   176 with \includegraphics of LaTeX;
   177 
   178 * proper spacing of consecutive markup elements, especially text
   179 blocks after section headings;
   180 
   181 * support bold style (for single symbols only), input syntax is like
   182 this: "\<^bold>\<alpha>" or "\<^bold>A";
   183 
   184 * \<bullet> is now output as bold \cdot by default, which looks much
   185 better in printed text;
   186 
   187 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   188 note that these symbols are currently unavailable in Proof General /
   189 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   190 
   191 * isatool latex no longer depends on changed TEXINPUTS, instead
   192 isatool document copies the Isabelle style files to the target
   193 location;
   194 
   195 
   196 *** Isar ***
   197 
   198 * Pure/Provers: improved proof by cases and induction;
   199   - 'case' command admits impromptu naming of parameters (such as
   200     "case (Suc n)");
   201   - 'induct' method divinates rule instantiation from the inductive
   202     claim; no longer requires excessive ?P bindings for proper
   203     instantiation of cases;
   204   - 'induct' method properly enumerates all possibilities of set/type
   205     rules; as a consequence facts may be also passed through *type*
   206     rules without further ado;
   207   - 'induct' method now derives symbolic cases from the *rulified*
   208     rule (before it used to rulify cases stemming from the internal
   209     atomized version); this means that the context of a non-atomic
   210     statement becomes is included in the hypothesis, avoiding the
   211     slightly cumbersome show "PROP ?case" form;
   212   - 'induct' may now use elim-style induction rules without chaining
   213     facts, using ``missing'' premises from the goal state; this allows
   214     rules stemming from inductive sets to be applied in unstructured
   215     scripts, while still benefitting from proper handling of non-atomic
   216     statements; NB: major inductive premises need to be put first, all
   217     the rest of the goal is passed through the induction;
   218   - 'induct' proper support for mutual induction involving non-atomic
   219     rule statements (uses the new concept of simultaneous goals, see
   220     below);
   221   - append all possible rule selections, but only use the first
   222     success (no backtracking);
   223   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   224   - undeclared rule case names default to numbers 1, 2, 3, ...;
   225   - added 'print_induct_rules' (covered by help item in recent Proof
   226     General versions);
   227   - moved induct/cases attributes to Pure, methods to Provers;
   228   - generic method setup instantiated for FOL and HOL;
   229 
   230 * Pure: support multiple simultaneous goal statements, for example
   231 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   232 meta-level mechanism, this acts as if several individual goals had
   233 been stated separately; in particular common proof methods need to be
   234 repeated in order to cover all claims; note that a single elimination
   235 step is *not* sufficient to establish the two conjunctions, so this
   236 fails:
   237 
   238   assume "A & B" then have A and B ..   (*".." fails*)
   239 
   240 better use "obtain" in situations as above; alternative refer to
   241 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   242 
   243 * Pure: proper integration with ``locales''; unlike the original
   244 version by Florian Kammüller, Isar locales package high-level proof
   245 contexts rather than raw logical ones (e.g. we admit to include
   246 attributes everywhere); operations on locales include merge and
   247 rename; support for implicit arguments (``structures''); simultaneous
   248 type-inference over imports and text; see also HOL/ex/Locales.thy for
   249 some examples;
   250 
   251 * Pure: the following commands have been ``localized'', supporting a
   252 target locale specification "(in name)": 'lemma', 'theorem',
   253 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   254 stored both within the locale and at the theory level (exported and
   255 qualified by the locale name);
   256 
   257 * Pure: theory goals may now be specified in ``long'' form, with
   258 ad-hoc contexts consisting of arbitrary locale elements. for example
   259 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   260 definitions may be given, too); the result is a meta-level rule with
   261 the context elements being discharged in the obvious way;
   262 
   263 * Pure: new proof command 'using' allows to augment currently used
   264 facts after a goal statement ('using' is syntactically analogous to
   265 'apply', but acts on the goal's facts only); this allows chained facts
   266 to be separated into parts given before and after a claim, as in
   267 ``from a and b have C using d and e <proof>'';
   268 
   269 * Pure: renamed "antecedent" case to "rule_context";
   270 
   271 * Pure: new 'judgment' command records explicit information about the
   272 object-logic embedding (used by several tools internally); no longer
   273 use hard-wired "Trueprop";
   274 
   275 * Pure: added 'corollary' command;
   276 
   277 * Pure: fixed 'token_translation' command;
   278 
   279 * Pure: removed obsolete 'exported' attribute;
   280 
   281 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   282 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   283 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   284 
   285 * Pure: method 'atomize' presents local goal premises as object-level
   286 statements (atomic meta-level propositions); setup controlled via
   287 rewrite rules declarations of 'atomize' attribute; example
   288 application: 'induct' method with proper rule statements in improper
   289 proof *scripts*;
   290 
   291 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   292 now consider the syntactic context of assumptions, giving a better
   293 chance to get type-inference of the arguments right (this is
   294 especially important for locales);
   295 
   296 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   297 mode;
   298 
   299 * Pure/obtain: the formal conclusion "thesis", being marked as
   300 ``internal'', may no longer be reference directly in the text;
   301 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   302 situations;
   303 
   304 * Pure: generic 'sym' attribute which declares a rule both as pure
   305 'elim?' and for the 'symmetric' operation;
   306 
   307 * Pure: marginal comments ``--'' may now occur just anywhere in the
   308 text; the fixed correlation with particular command syntax has been
   309 discontinued;
   310 
   311 * Pure: new method 'rules' is particularly well-suited for proof
   312 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   313 but often produces more compact proof terms with less detours;
   314 
   315 * Pure/Provers/classical: simplified integration with pure rule
   316 attributes and methods; the classical "intro?/elim?/dest?"
   317 declarations coincide with the pure ones; the "rule" method no longer
   318 includes classically swapped intros; "intro" and "elim" methods no
   319 longer pick rules from the context; also got rid of ML declarations
   320 AddXIs/AddXEs/AddXDs; all of this has some potential for
   321 INCOMPATIBILITY;
   322 
   323 * Provers/classical: attribute 'swapped' produces classical inversions
   324 of introduction rules;
   325 
   326 * Provers/simplifier: 'simplified' attribute may refer to explicit
   327 rules instead of full simplifier context; 'iff' attribute handles
   328 conditional rules;
   329 
   330 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   331 
   332 * HOL: 'recdef' now fails on unfinished automated proofs, use
   333 "(permissive)" option to recover old behavior;
   334 
   335 * HOL: 'inductive' no longer features separate (collective) attributes
   336 for 'intros' (was found too confusing);
   337 
   338 * HOL: properly declared induction rules less_induct and
   339 wf_induct_rule;
   340 
   341 
   342 *** HOL ***
   343 
   344 * HOL: moved over to sane numeral syntax; the new policy is as
   345 follows:
   346 
   347   - 0 and 1 are polymorphic constants, which are defined on any
   348   numeric type (nat, int, real etc.);
   349 
   350   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   351   binary representation internally;
   352 
   353   - type nat has special constructor Suc, and generally prefers Suc 0
   354   over 1::nat and Suc (Suc 0) over 2::nat;
   355 
   356 This change may cause significant problems of INCOMPATIBILITY; here
   357 are some hints on converting existing sources:
   358 
   359   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   360   entities, so expressions involving "-" (unary or binary minus) need
   361   to be spaced properly;
   362 
   363   - existing occurrences of "1" may need to be constraint "1::nat" or
   364   even replaced by Suc 0; similar for old "2";
   365 
   366   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   367 
   368   - remove all special provisions on numerals in proofs;
   369 
   370 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   371 representation (depends on bin_arith_simps in the default context);
   372 
   373 * HOL: symbolic syntax for x^2 (numeral 2);
   374 
   375 * HOL: the class of all HOL types is now called "type" rather than
   376 "term"; INCOMPATIBILITY, need to adapt references to this type class
   377 in axclass/classes, instance/arities, and (usually rare) occurrences
   378 in typings (of consts etc.); internally the class is called
   379 "HOL.type", ML programs should refer to HOLogic.typeS;
   380 
   381 * HOL/record package improvements:
   382   - new derived operations "fields" to build a partial record section,
   383     "extend" to promote a fixed record to a record scheme, and
   384     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   385     declared as simp by default;
   386   - shared operations ("more", "fields", etc.) now need to be always
   387     qualified) --- potential INCOMPATIBILITY;
   388   - removed "make_scheme" operations (use "make" with "extend") --
   389     INCOMPATIBILITY;
   390   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   391   - provides cases/induct rules for use with corresponding Isar
   392     methods (for concrete records, record schemes, concrete more
   393     parts, and schematic more parts -- in that order);
   394   - internal definitions directly based on a light-weight abstract
   395     theory of product types over typedef rather than datatype;
   396 
   397 * HOL: generic code generator for generating executable ML code from
   398 specifications; specific support for HOL constructs such as inductive
   399 datatypes and sets, as well as recursive functions; can be invoked
   400 via 'generate_code' theory section;
   401 
   402 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   403 
   404 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   405 (beware of argument permutation!);
   406 
   407 * HOL: linorder_less_split superseded by linorder_cases;
   408 
   409 * HOL/List: "nodups" renamed to "distinct";
   410 
   411 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   412 to peripheral theory "Hilbert_Choice";
   413 
   414 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   415 in this (rare) case use:
   416 
   417   delSWrapper "split_all_tac"
   418   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   419 
   420 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   421 MAY FAIL;
   422 
   423 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   424 Isabelle's type classes, ^ on functions and relations has too general
   425 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   426 necessary to attach explicit type constraints;
   427 
   428 * HOL/Relation: the prefix name of the infix "O" has been changed from
   429 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   430 renamed accordingly (eg "compI" -> "rel_compI").
   431 
   432 * HOL: syntax translations now work properly with numerals and records
   433 expressions;
   434 
   435 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   436 of "lam" -- INCOMPATIBILITY;
   437 
   438 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   439 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   440 renamed "Product_Type.unit";
   441 
   442 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   443 
   444 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   445 the "cases" method);
   446 
   447 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   448 Florian Kammüller);
   449 
   450 * HOL/IMP: updated and converted to new-style theory format; several
   451 parts turned into readable document, with proper Isar proof texts and
   452 some explanations (by Gerwin Klein);
   453 
   454 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   455 
   456 * HOL-Hyperreal is now a logic image;
   457 
   458 
   459 *** HOLCF ***
   460 
   461 * Isar: consts/constdefs supports mixfix syntax for continuous
   462 operations;
   463 
   464 * Isar: domain package adapted to new-style theory format, e.g. see
   465 HOLCF/ex/Dnat.thy;
   466 
   467 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   468 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   469 lift.induct_tac, always use UU instead of Undef;
   470 
   471 * HOLCF/IMP: updated and converted to new-style theory;
   472 
   473 
   474 *** ZF ***
   475 
   476 * Isar: proper integration of logic-specific tools and packages,
   477 including theory commands '(co)inductive', '(co)datatype',
   478 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   479 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   480 
   481 * theory Main no longer includes AC; for the Axiom of Choice, base
   482 your theory on Main_ZFC;
   483 
   484 * the integer library now covers quotients and remainders, with many
   485 laws relating division to addition, multiplication, etc.;
   486 
   487 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   488 typeless version of the formalism;
   489 
   490 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   491 format;
   492 
   493 * ZF/Induct: new directory for examples of inductive definitions,
   494 including theory Multiset for multiset orderings; converted to
   495 new-style theory format;
   496 
   497 * ZF: many new theorems about lists, ordinals, etc.;
   498 
   499 
   500 *** General ***
   501 
   502 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   503 variable proof controls level of detail: 0 = no proofs (only oracle
   504 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   505 also ref manual for further ML interfaces;
   506 
   507 * Pure/axclass: removed obsolete ML interface
   508 goal_subclass/goal_arity;
   509 
   510 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   511 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   512 separate tokens, so expressions involving minus need to be spaced
   513 properly;
   514 
   515 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   516 rather than "infixl" or "infixr";
   517 
   518 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   519 sort constraint specifications in type inference; e.g. "x::_::foo"
   520 ensures that the type of "x" is of sort "foo" (but not necessarily a
   521 type variable);
   522 
   523 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   524 control output of nested => (types); the default behavior is
   525 "type_brackets";
   526 
   527 * Pure/syntax: builtin parse translation for "_constify" turns valued
   528 tokens into AST constants;
   529 
   530 * Pure/syntax: prefer later declarations of translations and print
   531 translation functions; potential INCOMPATIBILITY: need to reverse
   532 multiple declarations for same syntax element constant;
   533 
   534 * Pure/show_hyps reset by default (in accordance to existing Isar
   535 practice);
   536 
   537 * Provers/classical: renamed addaltern to addafter, addSaltern to
   538 addSafter;
   539 
   540 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   541 as well;
   542 
   543 * system: tested support for MacOS X; should be able to get Isabelle +
   544 Proof General to work in a plain Terminal after installing Poly/ML
   545 (e.g. from the Isabelle distribution area) and GNU bash alone
   546 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   547 support requires further installations, e.g. from
   548 http://fink.sourceforge.net/);
   549 
   550 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   551 
   552 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   553 of 40 MB), cf. ML_OPTIONS;
   554 
   555 * system: Proof General keywords specification is now part of the
   556 Isabelle distribution (see etc/isar-keywords.el);
   557 
   558 * system: support for persistent Proof General sessions (refrain from
   559 outdating all loaded theories on startup); user may create writable
   560 logic images like this: ``isabelle -q HOL Test'';
   561 
   562 * system: smart selection of Isabelle process versus Isabelle
   563 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   564 run both "isabelle" and "Isabelle" even if file names are badly
   565 damaged (executable inspects the case of the first letter of its own
   566 name); added separate "isabelle-process" and "isabelle-interface";
   567 
   568 * system: refrain from any attempt at filtering input streams; no
   569 longer support ``8bit'' encoding of old isabelle font, instead proper
   570 iso-latin characters may now be used; the related isatools
   571 "symbolinput" and "nonascii" have disappeared as well;
   572 
   573 * system: removed old "xterm" interface (the print modes "xterm" and
   574 "xterm_color" are still available for direct use in a suitable
   575 terminal);
   576 
   577 
   578 
   579 New in Isabelle99-2 (February 2001)
   580 -----------------------------------
   581 
   582 *** Overview of INCOMPATIBILITIES ***
   583 
   584 * HOL: please note that theories in the Library and elsewhere often use the
   585 new-style (Isar) format; to refer to their theorems in an ML script you must
   586 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   587 
   588 * HOL: inductive package no longer splits induction rule aggressively,
   589 but only as far as specified by the introductions given; the old
   590 format may be recovered via ML function complete_split_rule or attribute
   591 'split_rule (complete)';
   592 
   593 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   594 gfp_Tarski to gfp_unfold;
   595 
   596 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   597 
   598 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   599 relation); infix "^^" has been renamed "``"; infix "``" has been
   600 renamed "`"; "univalent" has been renamed "single_valued";
   601 
   602 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   603 operation;
   604 
   605 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   606 
   607 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   608 
   609 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   610 consequence, it is no longer monotonic wrt. the local goal context
   611 (which is now passed through the inductive cases);
   612 
   613 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   614 \<gg> to \<ggreater>;
   615 
   616 
   617 *** Document preparation ***
   618 
   619 * \isabellestyle{NAME} selects version of Isabelle output (currently
   620 available: are "it" for near math-mode best-style output, "sl" for
   621 slanted text style, and "tt" for plain type-writer; if no
   622 \isabellestyle command is given, output is according to slanted
   623 type-writer);
   624 
   625 * support sub/super scripts (for single symbols only), input syntax is
   626 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   627 
   628 * some more standard symbols; see Appendix A of the system manual for
   629 the complete list of symbols defined in isabellesym.sty;
   630 
   631 * improved isabelle style files; more abstract symbol implementation
   632 (should now use \isamath{...} and \isatext{...} in custom symbol
   633 definitions);
   634 
   635 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   636 state; Note that presentation of goal states does not conform to
   637 actual human-readable proof documents.  Please do not include goal
   638 states into document output unless you really know what you are doing!
   639 
   640 * proper indentation of antiquoted output with proportional LaTeX
   641 fonts;
   642 
   643 * no_document ML operator temporarily disables LaTeX document
   644 generation;
   645 
   646 * isatool unsymbolize tunes sources for plain ASCII communication;
   647 
   648 
   649 *** Isar ***
   650 
   651 * Pure: Isar now suffers initial goal statements to contain unbound
   652 schematic variables (this does not conform to actual readable proof
   653 documents, due to unpredictable outcome and non-compositional proof
   654 checking); users who know what they are doing may use schematic goals
   655 for Prolog-style synthesis of proven results;
   656 
   657 * Pure: assumption method (an implicit finishing) now handles actual
   658 rules as well;
   659 
   660 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   661 initial goal, declare "that" only as Pure intro (only for single
   662 steps); the "that" rule assumption may now be involved in implicit
   663 finishing, thus ".." becomes a feasible for trivial obtains;
   664 
   665 * Pure: default proof step now includes 'intro_classes'; thus trivial
   666 instance proofs may be performed by "..";
   667 
   668 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   669 statements as well;
   670 
   671 * Pure: more robust selection of calculational rules;
   672 
   673 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   674 rule (as well as the assumption rule);
   675 
   676 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   677 lemmas, using the graph browser tool;
   678 
   679 * Pure: predict failure of "show" in interactive mode;
   680 
   681 * Pure: 'thms_containing' now takes actual terms as arguments;
   682 
   683 * HOL: improved method 'induct' --- now handles non-atomic goals
   684 (potential INCOMPATIBILITY); tuned error handling;
   685 
   686 * HOL: cases and induct rules now provide explicit hints about the
   687 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   688 any remaining facts are inserted into the goal verbatim;
   689 
   690 * HOL: local contexts (aka cases) may now contain term bindings as
   691 well; the 'cases' and 'induct' methods new provide a ?case binding for
   692 the result to be shown in each case;
   693 
   694 * HOL: added 'recdef_tc' command;
   695 
   696 * isatool convert assists in eliminating legacy ML scripts;
   697 
   698 
   699 *** HOL ***
   700 
   701 * HOL/Library: a collection of generic theories to be used together
   702 with main HOL; the theory loader path already includes this directory
   703 by default; the following existing theories have been moved here:
   704 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   705 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   706 
   707 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   708 modelling and verification task performed in Isabelle/HOL +
   709 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   710 
   711 * HOL/Algebra: special summation operator SUM no longer exists, it has
   712 been replaced by setsum; infix 'assoc' now has priority 50 (like
   713 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   714 'domain', this makes the theory consistent with mathematical
   715 literature;
   716 
   717 * HOL basics: added overloaded operations "inverse" and "divide"
   718 (infix "/"), syntax for generic "abs" operation, generic summation
   719 operator \<Sum>;
   720 
   721 * HOL/typedef: simplified package, provide more useful rules (see also
   722 HOL/subset.thy);
   723 
   724 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   725 now expressed as a proper nested rule (old-style tactic scripts may
   726 require atomize_strip_tac to cope with non-atomic premises);
   727 
   728 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   729 to "split_conv" (old name still available for compatibility);
   730 
   731 * HOL: improved concrete syntax for strings (e.g. allows translation
   732 rules with string literals);
   733 
   734 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   735  and Fleuriot's mechanization of analysis, including the transcendental
   736  functions for the reals;
   737 
   738 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   739 
   740 
   741 *** CTT ***
   742 
   743 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   744 "lam" is displayed as TWO lambda-symbols
   745 
   746 * CTT: theory Main now available, containing everything (that is, Bool
   747 and Arith);
   748 
   749 
   750 *** General ***
   751 
   752 * Pure: the Simplifier has been implemented properly as a derived rule
   753 outside of the actual kernel (at last!); the overall performance
   754 penalty in practical applications is about 50%, while reliability of
   755 the Isabelle inference kernel has been greatly improved;
   756 
   757 * print modes "brackets" and "no_brackets" control output of nested =>
   758 (types) and ==> (props); the default behaviour is "brackets";
   759 
   760 * Provers: fast_tac (and friends) now handle actual object-logic rules
   761 as assumptions as well;
   762 
   763 * system: support Poly/ML 4.0;
   764 
   765 * system: isatool install handles KDE version 1 or 2;
   766 
   767 
   768 
   769 New in Isabelle99-1 (October 2000)
   770 ----------------------------------
   771 
   772 *** Overview of INCOMPATIBILITIES ***
   773 
   774 * HOL: simplification of natural numbers is much changed; to partly
   775 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   776 issue the following ML commands:
   777 
   778   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   779   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   780 
   781 * HOL: simplification no longer dives into case-expressions; this is
   782 controlled by "t.weak_case_cong" for each datatype t;
   783 
   784 * HOL: nat_less_induct renamed to less_induct;
   785 
   786 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   787 fixsome to patch .thy and .ML sources automatically;
   788 
   789   select_equality  -> some_equality
   790   select_eq_Ex     -> some_eq_ex
   791   selectI2EX       -> someI2_ex
   792   selectI2         -> someI2
   793   selectI          -> someI
   794   select1_equality -> some1_equality
   795   Eps_sym_eq       -> some_sym_eq_trivial
   796   Eps_eq           -> some_eq_trivial
   797 
   798 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   799 
   800 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   801 instead);
   802 
   803 * HOL: the recursion equations generated by 'recdef' are now called
   804 f.simps instead of f.rules;
   805 
   806 * HOL: qed_spec_mp now also handles bounded ALL as well;
   807 
   808 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   809 sometimes be needed;
   810 
   811 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   812 
   813 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   814 
   815 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   816 product is now "<*>" instead of "Times"; the lexicographic product is
   817 now "<*lex*>" instead of "**";
   818 
   819 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   820 of main HOL, but was unused); better use HOL's datatype package;
   821 
   822 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   823 the old syntax may be recovered as follows:
   824 
   825   syntax (symbols)
   826     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   827       (infixl "\\<oplus>" 100)
   828 
   829 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   830 
   831 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   832 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   833 internally;
   834 
   835 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   836 changed from A/r to A//r;
   837 
   838 * ZF: new treatment of arithmetic (nat & int) may break some old
   839 proofs;
   840 
   841 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   842 rulify -> rule_format, elimify -> elim_format, ...);
   843 
   844 * Isar/Provers: intro/elim/dest attributes changed; renamed
   845 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   846 should have to change intro!! to intro? only); replaced "delrule" by
   847 "rule del";
   848 
   849 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   850 
   851 * Provers: strengthened force_tac by using new first_best_tac;
   852 
   853 * LaTeX document preparation: several changes of isabelle.sty (see
   854 lib/texinputs);
   855 
   856 
   857 *** Document preparation ***
   858 
   859 * formal comments (text blocks etc.) in new-style theories may now
   860 contain antiquotations of thm/prop/term/typ/text to be presented
   861 according to latex print mode; concrete syntax is like this:
   862 @{term[show_types] "f(x) = a + x"};
   863 
   864 * isatool mkdir provides easy setup of Isabelle session directories,
   865 including proper document sources;
   866 
   867 * generated LaTeX sources are now deleted after successful run
   868 (isatool document -c); may retain a copy somewhere else via -D option
   869 of isatool usedir;
   870 
   871 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   872 style files, achieving self-contained LaTeX sources and simplifying
   873 LaTeX debugging;
   874 
   875 * old-style theories now produce (crude) LaTeX output as well;
   876 
   877 * browser info session directories are now self-contained (may be put
   878 on WWW server seperately); improved graphs of nested sessions; removed
   879 graph for 'all sessions';
   880 
   881 * several improvements in isabelle style files; \isabellestyle{it}
   882 produces fake math mode output; \isamarkupheader is now \section by
   883 default; see lib/texinputs/isabelle.sty etc.;
   884 
   885 
   886 *** Isar ***
   887 
   888 * Isar/Pure: local results and corresponding term bindings are now
   889 subject to Hindley-Milner polymorphism (similar to ML); this
   890 accommodates incremental type-inference very nicely;
   891 
   892 * Isar/Pure: new derived language element 'obtain' supports
   893 generalized existence reasoning;
   894 
   895 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   896 support accumulation of results, without applying any rules yet;
   897 useful to collect intermediate results without explicit name
   898 references, and for use with transitivity rules with more than 2
   899 premises;
   900 
   901 * Isar/Pure: scalable support for case-analysis type proofs: new
   902 'case' language element refers to local contexts symbolically, as
   903 produced by certain proof methods; internally, case names are attached
   904 to theorems as "tags";
   905 
   906 * Isar/Pure: theory command 'hide' removes declarations from
   907 class/type/const name spaces;
   908 
   909 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   910 indicate potential overloading;
   911 
   912 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   913 
   914 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   915 "{a,b,c}" instead of {a,b,c};
   916 
   917 * Isar/Pure now provides its own version of intro/elim/dest
   918 attributes; useful for building new logics, but beware of confusion
   919 with the version in Provers/classical;
   920 
   921 * Isar/Pure: the local context of (non-atomic) goals is provided via
   922 case name 'antecedent';
   923 
   924 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   925 to the current context is now done automatically);
   926 
   927 * Isar/Pure: theory command 'method_setup' provides a simple interface
   928 for definining proof methods in ML;
   929 
   930 * Isar/Provers: intro/elim/dest attributes changed; renamed
   931 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   932 most cases, one should have to change intro!! to intro? only);
   933 replaced "delrule" by "rule del";
   934 
   935 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   936 'symmetric' attribute (the latter supercedes [RS sym]);
   937 
   938 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   939 method modifier); 'simp' method: 'only:' modifier removes loopers as
   940 well (including splits);
   941 
   942 * Isar/Provers: Simplifier and Classical methods now support all kind
   943 of modifiers used in the past, including 'cong', 'iff', etc.
   944 
   945 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   946 of Simplifier and Classical reasoner);
   947 
   948 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   949 now support named cases; major packages (inductive, datatype, primrec,
   950 recdef) support case names and properly name parameters;
   951 
   952 * Isar/HOL: new transitivity rules for substitution in inequalities --
   953 monotonicity conditions are extracted to be proven at end of
   954 calculations;
   955 
   956 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   957 method anyway;
   958 
   959 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   960 split_if split_if_asm; datatype package provides theorems foo.splits =
   961 foo.split foo.split_asm for each datatype;
   962 
   963 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   964 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   965 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   966 use "(cases (simplified))" method in proper proof texts);
   967 
   968 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   969 
   970 * Isar: names of theorems etc. may be natural numbers as well;
   971 
   972 * Isar: 'pr' command: optional arguments for goals_limit and
   973 ProofContext.prems_limit; no longer prints theory contexts, but only
   974 proof states;
   975 
   976 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   977 additional print modes to be specified; e.g. "pr(latex)" will print
   978 proof state according to the Isabelle LaTeX style;
   979 
   980 * Isar: improved support for emulating tactic scripts, including proof
   981 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   982 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   983 (for HOL datatypes);
   984 
   985 * Isar: simplified (more robust) goal selection of proof methods: 1st
   986 goal, all goals, or explicit goal specifier (tactic emulation); thus
   987 'proof method scripts' have to be in depth-first order;
   988 
   989 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   990 
   991 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   992 should instead use individual commands for printing items
   993 (print_commands, print_methods etc.);
   994 
   995 * Isar: added 'nothing' --- the empty list of theorems;
   996 
   997 
   998 *** HOL ***
   999 
  1000 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1001 corresponding virtual machine and a specification of its bytecode
  1002 verifier and a lightweight bytecode verifier, including proofs of
  1003 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1004 Cornelia Pusch (see also the homepage of project Bali at
  1005 http://isabelle.in.tum.de/Bali/);
  1006 
  1007 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1008 Clemens Ballarin;
  1009 
  1010 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1011 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1012 Rasmussen;
  1013 
  1014 * HOL/Lattice: fundamental concepts of lattice theory and order
  1015 structures, including duals, properties of bounds versus algebraic
  1016 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1017 Theorem for complete lattices etc.; may also serve as a demonstration
  1018 for abstract algebraic reasoning using axiomatic type classes, and
  1019 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1020 
  1021 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1022 von Oheimb;
  1023 
  1024 * HOL/IMPP: extension of IMP with local variables and mutually
  1025 recursive procedures, by David von Oheimb;
  1026 
  1027 * HOL/Lambda: converted into new-style theory and document;
  1028 
  1029 * HOL/ex/Multiquote: example of multiple nested quotations and
  1030 anti-quotations -- basically a generalized version of de-Bruijn
  1031 representation; very useful in avoiding lifting of operations;
  1032 
  1033 * HOL/record: added general record equality rule to simpset; fixed
  1034 select-update simplification procedure to handle extended records as
  1035 well; admit "r" as field name;
  1036 
  1037 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1038 other numeric types and also as the identity of groups, rings, etc.;
  1039 
  1040 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1041 Types nat and int belong to this axclass;
  1042 
  1043 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1044    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1045    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1046   two terms #m*u and #n*u are replaced by #(m+n)*u
  1047     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1048   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1049     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1050 
  1051 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1052 powerful prover for predicate logic but knows nothing of clasets; see
  1053 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1054 
  1055 * HOL: new version of "case_tac" subsumes both boolean case split and
  1056 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1057 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1058 
  1059 * HOL: simplification no longer dives into case-expressions: only the
  1060 selector expression is simplified, but not the remaining arms; to
  1061 enable full simplification of case-expressions for datatype t, you may
  1062 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1063 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1064 
  1065 * HOL/recdef: the recursion equations generated by 'recdef' for
  1066 function 'f' are now called f.simps instead of f.rules; if all
  1067 termination conditions are proved automatically, these simplification
  1068 rules are added to the simpset, as in primrec; rules may be named
  1069 individually as well, resulting in a separate list of theorems for
  1070 each equation;
  1071 
  1072 * HOL/While is a new theory that provides a while-combinator. It
  1073 permits the definition of tail-recursive functions without the
  1074 provision of a termination measure. The latter is necessary once the
  1075 invariant proof rule for while is applied.
  1076 
  1077 * HOL: new (overloaded) notation for the set of elements below/above
  1078 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1079 
  1080 * HOL: theorems impI, allI, ballI bound as "strip";
  1081 
  1082 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1083 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1084 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1085 
  1086 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1087 
  1088 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1089 main HOL, but was unused);
  1090 
  1091 * HOL: fewer consts declared as global (e.g. have to refer to
  1092 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1093 
  1094 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1095 in case of overlap with user translations (e.g. judgements over
  1096 tuples); (note that the underlying logical represenation is still
  1097 bogus);
  1098 
  1099 
  1100 *** ZF ***
  1101 
  1102 * ZF: simplification automatically cancels common terms in arithmetic
  1103 expressions over nat and int;
  1104 
  1105 * ZF: new treatment of nat to minimize type-checking: all operators
  1106 coerce their operands to a natural number using the function natify,
  1107 making the algebraic laws unconditional;
  1108 
  1109 * ZF: as above, for int: operators coerce their operands to an integer
  1110 using the function intify;
  1111 
  1112 * ZF: the integer library now contains many of the usual laws for the
  1113 orderings, including $<=, and monotonicity laws for $+ and $*;
  1114 
  1115 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1116 simplification;
  1117 
  1118 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1119 to the simplifier and classical reasoner simultaneously;
  1120 
  1121 
  1122 *** General ***
  1123 
  1124 * Provers: blast_tac now handles actual object-logic rules as
  1125 assumptions; note that auto_tac uses blast_tac internally as well;
  1126 
  1127 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1128 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1129 
  1130 * Provers: delrules now handles destruct rules as well (no longer need
  1131 explicit make_elim);
  1132 
  1133 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1134   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1135 use instead the strong form,
  1136   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1137 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1138 from destruct-rules;
  1139 
  1140 * Provers: Simplifier.easy_setup provides a fast path to basic
  1141 Simplifier setup for new object-logics;
  1142 
  1143 * Pure: AST translation rules no longer require constant head on LHS;
  1144 
  1145 * Pure: improved name spaces: ambiguous output is qualified; support
  1146 for hiding of names;
  1147 
  1148 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1149 XSYMBOL_HOME; no longer need to do manual configuration in most
  1150 situations;
  1151 
  1152 * system: compression of ML heaps images may now be controlled via -c
  1153 option of isabelle and isatool usedir (currently only observed by
  1154 Poly/ML);
  1155 
  1156 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1157 useful for remote X11);
  1158 
  1159 * system: provide TAGS file for Isabelle sources;
  1160 
  1161 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1162 order;
  1163 
  1164 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1165 timing flag supersedes proof_timing and Toplevel.trace;
  1166 
  1167 * ML: new combinators |>> and |>>> for incremental transformations
  1168 with secondary results (e.g. certain theory extensions):
  1169 
  1170 * ML: PureThy.add_defs gets additional argument to indicate potential
  1171 overloading (usually false);
  1172 
  1173 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1174 results;
  1175 
  1176 
  1177 
  1178 New in Isabelle99 (October 1999)
  1179 --------------------------------
  1180 
  1181 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1182 
  1183 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1184 are no longer simplified.  (This allows the simplifier to unfold recursive
  1185 functional programs.)  To restore the old behaviour, declare
  1186 
  1187     Delcongs [if_weak_cong];
  1188 
  1189 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1190 complement;
  1191 
  1192 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1193 
  1194 * HOL/datatype: mutual_induct_tac no longer exists --
  1195   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1196 
  1197 * HOL/typedef: fixed type inference for representing set; type
  1198 arguments now have to occur explicitly on the rhs as type constraints;
  1199 
  1200 * ZF: The con_defs part of an inductive definition may no longer refer
  1201 to constants declared in the same theory;
  1202 
  1203 * HOL, ZF: the function mk_cases, generated by the inductive
  1204 definition package, has lost an argument.  To simplify its result, it
  1205 uses the default simpset instead of a supplied list of theorems.
  1206 
  1207 * HOL/List: the constructors of type list are now Nil and Cons;
  1208 
  1209 * Simplifier: the type of the infix ML functions
  1210         setSSolver addSSolver setSolver addSolver
  1211 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1212 for packaging solvers. A solver is created via
  1213         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1214 where the string argument is only a comment.
  1215 
  1216 
  1217 *** Proof tools ***
  1218 
  1219 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1220 decision procedure for linear arithmetic. Currently it is used for
  1221 types `nat', `int', and `real' in HOL (see below); it can, should and
  1222 will be instantiated for other types and logics as well.
  1223 
  1224 * The simplifier now accepts rewrite rules with flexible heads, eg
  1225      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1226   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1227   matching.
  1228 
  1229 
  1230 *** General ***
  1231 
  1232 * New Isabelle/Isar subsystem provides an alternative to traditional
  1233 tactical theorem proving; together with the ProofGeneral/isar user
  1234 interface it offers an interactive environment for developing human
  1235 readable proof documents (Isar == Intelligible semi-automated
  1236 reasoning); for further information see isatool doc isar-ref,
  1237 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1238 
  1239 * improved and simplified presentation of theories: better HTML markup
  1240 (including colors), graph views in several sizes; isatool usedir now
  1241 provides a proper interface for user theories (via -P option); actual
  1242 document preparation based on (PDF)LaTeX is available as well (for
  1243 new-style theories only); see isatool doc system for more information;
  1244 
  1245 * native support for Proof General, both for classic Isabelle and
  1246 Isabelle/Isar;
  1247 
  1248 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1249 using the graph browser tool;
  1250 
  1251 * Isabelle manuals now also available as PDF;
  1252 
  1253 * theory loader rewritten from scratch (may not be fully
  1254 bug-compatible); old loadpath variable has been replaced by show_path,
  1255 add_path, del_path, reset_path functions; new operations such as
  1256 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1257 isatool doc ref);
  1258 
  1259 * improved isatool install: option -k creates KDE application icon,
  1260 option -p DIR installs standalone binaries;
  1261 
  1262 * added ML_PLATFORM setting (useful for cross-platform installations);
  1263 more robust handling of platform specific ML images for SML/NJ;
  1264 
  1265 * the settings environment is now statically scoped, i.e. it is never
  1266 created again in sub-processes invoked from isabelle, isatool, or
  1267 Isabelle;
  1268 
  1269 * path element specification '~~' refers to '$ISABELLE_HOME';
  1270 
  1271 * in locales, the "assumes" and "defines" parts may be omitted if
  1272 empty;
  1273 
  1274 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1275 long arrows);
  1276 
  1277 * new print_mode "HTML";
  1278 
  1279 * new flag show_tags controls display of tags of theorems (which are
  1280 basically just comments that may be attached by some tools);
  1281 
  1282 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1283 mode and goal output format:
  1284 
  1285 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1286 244c244
  1287 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1288 ---
  1289 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1290 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1291 181c181
  1292 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1293 ---
  1294 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1295 
  1296 * function bind_thms stores lists of theorems (cf. bind_thm);
  1297 
  1298 * new shorthand tactics ftac, eatac, datac, fatac;
  1299 
  1300 * qed (and friends) now accept "" as result name; in that case the
  1301 theorem is not stored, but proper checks and presentation of the
  1302 result still apply;
  1303 
  1304 * theorem database now also indexes constants "Trueprop", "all",
  1305 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1306 
  1307 
  1308 *** HOL ***
  1309 
  1310 ** HOL arithmetic **
  1311 
  1312 * There are now decision procedures for linear arithmetic over nat and
  1313 int:
  1314 
  1315 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1316 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1317 are treated as atomic; subformulae not involving type `nat' or `int'
  1318 are ignored; quantified subformulae are ignored unless they are
  1319 positive universal or negative existential. The tactic has to be
  1320 invoked by hand and can be a little bit slow. In particular, the
  1321 running time is exponential in the number of occurrences of `min' and
  1322 `max', and `-' on `nat'.
  1323 
  1324 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1325 (negated) (in)equalities among the premises and the conclusion into
  1326 account (i.e. no compound formulae) and does not know about `min' and
  1327 `max', and `-' on `nat'. It is fast and is used automatically by the
  1328 simplifier.
  1329 
  1330 NB: At the moment, these decision procedures do not cope with mixed
  1331 nat/int formulae where the two parts interact, such as `m < n ==>
  1332 int(m) < int(n)'.
  1333 
  1334 * HOL/Numeral provides a generic theory of numerals (encoded
  1335 efficiently as bit strings); setup for types nat/int/real is in place;
  1336 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1337 int, existing theories and proof scripts may require a few additional
  1338 type constraints;
  1339 
  1340 * integer division and remainder can now be performed on constant
  1341 arguments;
  1342 
  1343 * many properties of integer multiplication, division and remainder
  1344 are now available;
  1345 
  1346 * An interface to the Stanford Validity Checker (SVC) is available through the
  1347 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1348 are proved automatically.  SVC must be installed separately, and its results
  1349 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1350 invocation of the underlying oracle).  For SVC see
  1351   http://verify.stanford.edu/SVC
  1352 
  1353 * IsaMakefile: the HOL-Real target now builds an actual image;
  1354 
  1355 
  1356 ** HOL misc **
  1357 
  1358 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1359 (in Isabelle/Isar) -- by Gertrud Bauer;
  1360 
  1361 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1362 analysis for assembly languages with subtypes;
  1363 
  1364 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1365 -- avoids syntactic ambiguities and treats state, transition, and
  1366 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1367 changed syntax and (many) tactics;
  1368 
  1369 * HOL/inductive: Now also handles more general introduction rules such
  1370   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1371   theorems are now maintained within the theory (maintained via the
  1372   "mono" attribute);
  1373 
  1374 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1375   (using function types) such as
  1376 
  1377   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1378 
  1379 * HOL/record: record_simproc (part of the default simpset) takes care
  1380 of selectors applied to updated records; record_split_tac is no longer
  1381 part of the default claset; update_defs may now be removed from the
  1382 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1383 
  1384   claset_ref () := claset() addSWrapper record_split_wrapper;
  1385   Delsimprocs [record_simproc]
  1386 
  1387 * HOL/typedef: fixed type inference for representing set; type
  1388 arguments now have to occur explicitly on the rhs as type constraints;
  1389 
  1390 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1391 names rather than an ML expression;
  1392 
  1393 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1394 supplied later.  Program schemes can be defined, such as
  1395     "While B C s = (if B s then While B C (C s) else s)"
  1396 where the well-founded relation can be chosen after B and C have been given.
  1397 
  1398 * HOL/List: the constructors of type list are now Nil and Cons;
  1399 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1400 course, ML tools referring to List.list.op # etc. have to be adapted;
  1401 
  1402 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1403 disabled by default; run isabelle with option -m HOL to get back to
  1404 the original Gordon/HOL-style output;
  1405 
  1406 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1407 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1408 
  1409 * HOL basic syntax simplified (more orthogonal): all variants of
  1410 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1411 Eps operator is provided as well: "SOME x. P[x]";
  1412 
  1413 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1414 
  1415 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1416 thus available for user theories;
  1417 
  1418 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1419 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1420 time;
  1421 
  1422 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1423 several times and then mp;
  1424 
  1425 
  1426 *** LK ***
  1427 
  1428 * the notation <<...>> is now available as a notation for sequences of
  1429 formulas;
  1430 
  1431 * the simplifier is now installed
  1432 
  1433 * the axiom system has been generalized (thanks to Soren Heilmann)
  1434 
  1435 * the classical reasoner now has a default rule database
  1436 
  1437 
  1438 *** ZF ***
  1439 
  1440 * new primrec section allows primitive recursive functions to be given
  1441 directly (as in HOL) over datatypes and the natural numbers;
  1442 
  1443 * new tactics induct_tac and exhaust_tac for induction (or case
  1444 analysis) over datatypes and the natural numbers;
  1445 
  1446 * the datatype declaration of type T now defines the recursor T_rec;
  1447 
  1448 * simplification automatically does freeness reasoning for datatype
  1449 constructors;
  1450 
  1451 * automatic type-inference, with AddTCs command to insert new
  1452 type-checking rules;
  1453 
  1454 * datatype introduction rules are now added as Safe Introduction rules
  1455 to the claset;
  1456 
  1457 * the syntax "if P then x else y" is now available in addition to
  1458 if(P,x,y);
  1459 
  1460 
  1461 *** Internal programming interfaces ***
  1462 
  1463 * tuned simplifier trace output; new flag debug_simp;
  1464 
  1465 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1466 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1467 
  1468 * AxClass.axclass_tac lost the theory argument;
  1469 
  1470 * tuned current_goals_markers semantics: begin / end goal avoids
  1471 printing empty lines;
  1472 
  1473 * removed prs and prs_fn hook, which was broken because it did not
  1474 include \n in its semantics, forcing writeln to add one
  1475 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1476 string -> unit if you really want to output text without newline;
  1477 
  1478 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1479 plain output, interface builders may have to enable 'isabelle_font'
  1480 mode to get Isabelle font glyphs as before;
  1481 
  1482 * refined token_translation interface; INCOMPATIBILITY: output length
  1483 now of type real instead of int;
  1484 
  1485 * theory loader actions may be traced via new ThyInfo.add_hook
  1486 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1487 your own database of information attached to *whole* theories -- as
  1488 opposed to intra-theory data slots offered via TheoryDataFun;
  1489 
  1490 * proper handling of dangling sort hypotheses (at last!);
  1491 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1492 extra sort hypotheses that can be witnessed from the type signature;
  1493 the force_strip_shyps flag is gone, any remaining shyps are simply
  1494 left in the theorem (with a warning issued by strip_shyps_warning);
  1495 
  1496 
  1497 
  1498 New in Isabelle98-1 (October 1998)
  1499 ----------------------------------
  1500 
  1501 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1502 
  1503 * several changes of automated proof tools;
  1504 
  1505 * HOL: major changes to the inductive and datatype packages, including
  1506 some minor incompatibilities of theory syntax;
  1507 
  1508 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1509 called `inj_on';
  1510 
  1511 * HOL: removed duplicate thms in Arith:
  1512   less_imp_add_less  should be replaced by  trans_less_add1
  1513   le_imp_add_le      should be replaced by  trans_le_add1
  1514 
  1515 * HOL: unary minus is now overloaded (new type constraints may be
  1516 required);
  1517 
  1518 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1519 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1520 now taken as an integer constant.
  1521 
  1522 * Pure: ML function 'theory_of' renamed to 'theory';
  1523 
  1524 
  1525 *** Proof tools ***
  1526 
  1527 * Simplifier:
  1528   1. Asm_full_simp_tac is now more aggressive.
  1529      1. It will sometimes reorient premises if that increases their power to
  1530         simplify.
  1531      2. It does no longer proceed strictly from left to right but may also
  1532         rotate premises to achieve further simplification.
  1533      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1534      old Asm_full_simp_tac in that it does not rotate premises.
  1535   2. The simplifier now knows a little bit about nat-arithmetic.
  1536 
  1537 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1538 allows for selected deletion of wrappers, by introduction of names for
  1539 wrapper functionals.  This implies that addbefore, addSbefore,
  1540 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1541 and that adding two tactics with the same name overwrites the first
  1542 one (emitting a warning).
  1543   type wrapper = (int -> tactic) -> (int -> tactic)
  1544   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1545   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1546   delWrapper, delSWrapper: claset *  string            -> claset
  1547   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1548 
  1549 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1550 semantics; addbefore now affects only the unsafe part of step_tac
  1551 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1552 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1553 by Force_tac;
  1554 
  1555 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1556 compWrapper; added safe wrapper (and access functions for it);
  1557 
  1558 * HOL/split_all_tac is now much faster and fails if there is nothing
  1559 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1560 and the names of the automatically generated variables have changed.
  1561 split_all_tac has moved within claset() from unsafe wrappers to safe
  1562 wrappers, which means that !!-bound variables are split much more
  1563 aggressively, and safe_tac and clarify_tac now split such variables.
  1564 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1565 Note: the same holds for record_split_tac, which does the job of
  1566 split_all_tac for record fields.
  1567 
  1568 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1569 permanently to the default simpset using Addsplits just like
  1570 Addsimps. They can be removed via Delsplits just like
  1571 Delsimps. Lower-case versions are also available.
  1572 
  1573 * HOL/Simplifier: The rule split_if is now part of the default
  1574 simpset. This means that the simplifier will eliminate all occurrences
  1575 of if-then-else in the conclusion of a goal. To prevent this, you can
  1576 either remove split_if completely from the default simpset by
  1577 `Delsplits [split_if]' or remove it in a specific call of the
  1578 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1579 other case splitting rules to/from the default simpset: every datatype
  1580 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1581 t is the name of the datatype).
  1582 
  1583 * Classical reasoner / Simplifier combination: new force_tac (and
  1584 derivatives Force_tac, force) combines rewriting and classical
  1585 reasoning (and whatever other tools) similarly to auto_tac, but is
  1586 aimed to solve the given subgoal completely.
  1587 
  1588 
  1589 *** General ***
  1590 
  1591 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1592 and `goalw': the theory is no longer needed as an explicit argument -
  1593 the current theory context is used; assumptions are no longer returned
  1594 at the ML-level unless one of them starts with ==> or !!; it is
  1595 recommended to convert to these new commands using isatool fixgoal
  1596 (backup your sources first!);
  1597 
  1598 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1599 the current theory context, and 'theory' to lookup stored theories;
  1600 
  1601 * new theory section 'locale' for declaring constants, assumptions and
  1602 definitions that have local scope;
  1603 
  1604 * new theory section 'nonterminals' for purely syntactic types;
  1605 
  1606 * new theory section 'setup' for generic ML setup functions
  1607 (e.g. package initialization);
  1608 
  1609 * the distribution now includes Isabelle icons: see
  1610 lib/logo/isabelle-{small,tiny}.xpm;
  1611 
  1612 * isatool install - install binaries with absolute references to
  1613 ISABELLE_HOME/bin;
  1614 
  1615 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1616 
  1617 * print mode 'emacs' reserved for Isamode;
  1618 
  1619 * support multiple print (ast) translations per constant name;
  1620 
  1621 * theorems involving oracles are now printed with a suffixed [!];
  1622 
  1623 
  1624 *** HOL ***
  1625 
  1626 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1627 
  1628 * HOL/inductive package reorganized and improved: now supports mutual
  1629 definitions such as
  1630 
  1631   inductive EVEN ODD
  1632     intrs
  1633       null "0 : EVEN"
  1634       oddI "n : EVEN ==> Suc n : ODD"
  1635       evenI "n : ODD ==> Suc n : EVEN"
  1636 
  1637 new theorem list "elims" contains an elimination rule for each of the
  1638 recursive sets; inductive definitions now handle disjunctive premises
  1639 correctly (also ZF);
  1640 
  1641 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1642 "mutual_induct" no longer exists - the induction rule is always
  1643 contained in "induct";
  1644 
  1645 
  1646 * HOL/datatype package re-implemented and greatly improved: now
  1647 supports mutually recursive datatypes such as
  1648 
  1649   datatype
  1650     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1651             | SUM ('a aexp) ('a aexp)
  1652             | DIFF ('a aexp) ('a aexp)
  1653             | NUM 'a
  1654   and
  1655     'a bexp = LESS ('a aexp) ('a aexp)
  1656             | AND ('a bexp) ('a bexp)
  1657             | OR ('a bexp) ('a bexp)
  1658 
  1659 as well as indirectly recursive datatypes such as
  1660 
  1661   datatype
  1662     ('a, 'b) term = Var 'a
  1663                   | App 'b ((('a, 'b) term) list)
  1664 
  1665 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1666 induction on mutually / indirectly recursive datatypes.
  1667 
  1668 Primrec equations are now stored in theory and can be accessed via
  1669 <function_name>.simps.
  1670 
  1671 INCOMPATIBILITIES:
  1672 
  1673   - Theories using datatypes must now have theory Datatype as an
  1674     ancestor.
  1675   - The specific <typename>.induct_tac no longer exists - use the
  1676     generic induct_tac instead.
  1677   - natE has been renamed to nat.exhaust - use exhaust_tac
  1678     instead of res_inst_tac ... natE. Note that the variable
  1679     names in nat.exhaust differ from the names in natE, this
  1680     may cause some "fragile" proofs to fail.
  1681   - The theorems split_<typename>_case and split_<typename>_case_asm
  1682     have been renamed to <typename>.split and <typename>.split_asm.
  1683   - Since default sorts of type variables are now handled correctly,
  1684     some datatype definitions may have to be annotated with explicit
  1685     sort constraints.
  1686   - Primrec definitions no longer require function name and type
  1687     of recursive argument.
  1688 
  1689 Consider using isatool fixdatatype to adapt your theories and proof
  1690 scripts to the new package (backup your sources first!).
  1691 
  1692 
  1693 * HOL/record package: considerably improved implementation; now
  1694 includes concrete syntax for record types, terms, updates; theorems
  1695 for surjective pairing and splitting !!-bound record variables; proof
  1696 support is as follows:
  1697 
  1698   1) standard conversions (selectors or updates applied to record
  1699 constructor terms) are part of the standard simpset;
  1700 
  1701   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1702 made part of standard simpset and claset via addIffs;
  1703 
  1704   3) a tactic for record field splitting (record_split_tac) is part of
  1705 the standard claset (addSWrapper);
  1706 
  1707 To get a better idea about these rules you may retrieve them via
  1708 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1709 the name of your record type.
  1710 
  1711 The split tactic 3) conceptually simplifies by the following rule:
  1712 
  1713   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1714 
  1715 Thus any record variable that is bound by meta-all will automatically
  1716 blow up into some record constructor term, consequently the
  1717 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1718 solve record problems automatically.
  1719 
  1720 
  1721 * reorganized the main HOL image: HOL/Integ and String loaded by
  1722 default; theory Main includes everything;
  1723 
  1724 * automatic simplification of integer sums and comparisons, using cancellation;
  1725 
  1726 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1727 
  1728 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1729 
  1730 * many new identities for unions, intersections, set difference, etc.;
  1731 
  1732 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1733 called split_if, split_split, split_sum_case and split_nat_case (to go
  1734 with add/delsplits);
  1735 
  1736 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1737 (?x::unit) = (); this is made part of the default simpset, which COULD
  1738 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1739 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1740 unit_abs_eta_conv is added in order to counter the effect of
  1741 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1742 %u.f();
  1743 
  1744 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1745 makes more sense);
  1746 
  1747 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1748   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1749   disjointness reasoning but breaking a few old proofs.
  1750 
  1751 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1752 to 'converse' from 'inverse' (for compatibility with ZF and some
  1753 literature);
  1754 
  1755 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1756 the well-founded relation;
  1757 
  1758 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1759     Compl A.  The "Compl" syntax remains available as input syntax for this
  1760     release ONLY.
  1761 
  1762 * HOL/Update: new theory of function updates:
  1763     f(a:=b) == %x. if x=a then b else f x
  1764 may also be iterated as in f(a:=b,c:=d,...);
  1765 
  1766 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1767 
  1768 * HOL/List:
  1769   - new function list_update written xs[i:=v] that updates the i-th
  1770     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1771   - new function `upt' written [i..j(] which generates the list
  1772     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1773     bound write [i..j], which is a shorthand for [i..j+1(].
  1774   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1775 
  1776 * HOL/Arith:
  1777   - removed 'pred' (predecessor) function;
  1778   - generalized some theorems about n-1;
  1779   - many new laws about "div" and "mod";
  1780   - new laws about greatest common divisors (see theory ex/Primes);
  1781 
  1782 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1783 instead of "inverse";
  1784 
  1785 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1786   of the multiset ordering;
  1787 
  1788 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1789   (not included by default);
  1790 
  1791 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1792 
  1793 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1794   programs, i.e. different program variables may have different types.
  1795 
  1796 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1797   [previously, this check worked only if the rewrite rule was unconditional]
  1798   Now rew can involve either definitions or equalities (either == or =).
  1799 
  1800 
  1801 *** ZF ***
  1802 
  1803 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1804   only the theorems proved on ZF.ML;
  1805 
  1806 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1807   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1808   disjointness reasoning but breaking a few old proofs.
  1809 
  1810 * ZF/Update: new theory of function updates
  1811     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1812   may also be iterated as in f(a:=b,c:=d,...);
  1813 
  1814 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1815 
  1816 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1817   [previously, this check worked only if the rewrite rule was unconditional]
  1818   Now rew can involve either definitions or equalities (either == or =).
  1819 
  1820 * case_tac provided for compatibility with HOL
  1821     (like the old excluded_middle_tac, but with subgoals swapped)
  1822 
  1823 
  1824 *** Internal programming interfaces ***
  1825 
  1826 * Pure: several new basic modules made available for general use, see
  1827 also src/Pure/README;
  1828 
  1829 * improved the theory data mechanism to support encapsulation (data
  1830 kind name replaced by private Object.kind, acting as authorization
  1831 key); new type-safe user interface via functor TheoryDataFun; generic
  1832 print_data function becomes basically useless;
  1833 
  1834 * removed global_names compatibility flag -- all theory declarations
  1835 are qualified by default;
  1836 
  1837 * module Pure/Syntax now offers quote / antiquote translation
  1838 functions (useful for Hoare logic etc. with implicit dependencies);
  1839 see HOL/ex/Antiquote for an example use;
  1840 
  1841 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1842 cterm -> thm;
  1843 
  1844 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1845 subgoal;
  1846 
  1847 * Display.print_goals function moved to Locale.print_goals;
  1848 
  1849 * standard print function for goals supports current_goals_markers
  1850 variable for marking begin of proof, end of proof, start of goal; the
  1851 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1852 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1853 for example;
  1854 
  1855 
  1856 
  1857 New in Isabelle98 (January 1998)
  1858 --------------------------------
  1859 
  1860 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1861 
  1862 * changed lexical syntax of terms / types: dots made part of long
  1863 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1864 
  1865 * simpset (and claset) reference variable replaced by functions
  1866 simpset / simpset_ref;
  1867 
  1868 * no longer supports theory aliases (via merge) and non-trivial
  1869 implicit merge of thms' signatures;
  1870 
  1871 * most internal names of constants changed due to qualified names;
  1872 
  1873 * changed Pure/Sequence interface (see Pure/seq.ML);
  1874 
  1875 
  1876 *** General Changes ***
  1877 
  1878 * hierachically structured name spaces (for consts, types, axms, thms
  1879 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1880 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1881 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1882 long_names for fully qualified output names; NOTE: ML programs
  1883 (special tactics, packages etc.) referring to internal names may have
  1884 to be adapted to cope with fully qualified names; in case of severe
  1885 backward campatibility problems try setting 'global_names' at compile
  1886 time to have enrything declared within a flat name space; one may also
  1887 fine tune name declarations in theories via the 'global' and 'local'
  1888 section;
  1889 
  1890 * reimplemented the implicit simpset and claset using the new anytype
  1891 data filed in signatures; references simpset:simpset ref etc. are
  1892 replaced by functions simpset:unit->simpset and
  1893 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1894 to patch your ML files accordingly;
  1895 
  1896 * HTML output now includes theory graph data for display with Java
  1897 applet or isatool browser; data generated automatically via isatool
  1898 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1899 
  1900 * defs may now be conditional; improved rewrite_goals_tac to handle
  1901 conditional equations;
  1902 
  1903 * defs now admits additional type arguments, using TYPE('a) syntax;
  1904 
  1905 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1906 creates a new theory node; implicit merge of thms' signatures is
  1907 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1908 transfer:theory->thm->thm in (rare) cases;
  1909 
  1910 * improved handling of draft signatures / theories; draft thms (and
  1911 ctyps, cterms) are automatically promoted to real ones;
  1912 
  1913 * slightly changed interfaces for oracles: admit many per theory, named
  1914 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1915 
  1916 * print_goals: optional output of const types (set show_consts and
  1917 show_types);
  1918 
  1919 * improved output of warnings (###) and errors (***);
  1920 
  1921 * subgoal_tac displays a warning if the new subgoal has type variables;
  1922 
  1923 * removed old README and Makefiles;
  1924 
  1925 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1926 
  1927 * removed obsolete init_pps and init_database;
  1928 
  1929 * deleted the obsolete tactical STATE, which was declared by
  1930     fun STATE tacfun st = tacfun st st;
  1931 
  1932 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1933 (which abbreviates $HOME);
  1934 
  1935 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1936 use isatool fixseq to adapt your ML programs (this works for fully
  1937 qualified references to the Sequence structure only!);
  1938 
  1939 * use_thy no longer requires writable current directory; it always
  1940 reloads .ML *and* .thy file, if either one is out of date;
  1941 
  1942 
  1943 *** Classical Reasoner ***
  1944 
  1945 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1946 tactics that use classical reasoning to simplify a subgoal without
  1947 splitting it into several subgoals;
  1948 
  1949 * Safe_tac: like safe_tac but uses the default claset;
  1950 
  1951 
  1952 *** Simplifier ***
  1953 
  1954 * added simplification meta rules:
  1955     (asm_)(full_)simplify: simpset -> thm -> thm;
  1956 
  1957 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1958 logics (again);
  1959 
  1960 * added prems argument to simplification procedures;
  1961 
  1962 * HOL, FOL, ZF: added infix function `addsplits':
  1963   instead of `<simpset> setloop (split_tac <thms>)'
  1964   you can simply write `<simpset> addsplits <thms>'
  1965 
  1966 
  1967 *** Syntax ***
  1968 
  1969 * TYPE('a) syntax for type reflection terms;
  1970 
  1971 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1972 
  1973 * pretty printer: changed order of mixfix annotation preference (again!);
  1974 
  1975 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1976 
  1977 
  1978 *** HOL ***
  1979 
  1980 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1981   with `addloop' of the simplifier to faciliate case splitting in premises.
  1982 
  1983 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1984 
  1985 * HOL/Auth: new protocol proofs including some for the Internet
  1986   protocol TLS;
  1987 
  1988 * HOL/Map: new theory of `maps' a la VDM;
  1989 
  1990 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1991 cancelling out common nat summands from =, <, <= (in)equalities, or
  1992 differences; simplification procedures nat_cancel_factor for
  1993 cancelling common factor from =, <, <= (in)equalities over natural
  1994 sums; nat_cancel contains both kinds of procedures, it is installed by
  1995 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1996 
  1997 * HOL/simplifier: terms of the form
  1998   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1999   are rewritten to
  2000   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2001   and those of the form
  2002   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2003   are rewritten to
  2004   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2005 
  2006 * HOL/datatype
  2007   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2008 
  2009   P(t_case f1 ... fn x) =
  2010      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2011         ...
  2012        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2013      )
  2014 
  2015   and a theorem `split_t_case_asm' of the form
  2016 
  2017   P(t_case f1 ... fn x) =
  2018     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2019         ...
  2020        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2021      )
  2022   which can be added to a simpset via `addsplits'. The existing theorems
  2023   expand_list_case and expand_option_case have been renamed to
  2024   split_list_case and split_option_case.
  2025 
  2026 * HOL/Arithmetic:
  2027   - `pred n' is automatically converted to `n-1'.
  2028     Users are strongly encouraged not to use `pred' any longer,
  2029     because it will disappear altogether at some point.
  2030   - Users are strongly encouraged to write "0 < n" rather than
  2031     "n ~= 0". Theorems and proof tools have been modified towards this
  2032     `standard'.
  2033 
  2034 * HOL/Lists:
  2035   the function "set_of_list" has been renamed "set" (and its theorems too);
  2036   the function "nth" now takes its arguments in the reverse order and
  2037   has acquired the infix notation "!" as in "xs!n".
  2038 
  2039 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2040 
  2041 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2042   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2043 
  2044 * HOL/record: extensible records with schematic structural subtyping
  2045 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2046 still lacks various theorems and concrete record syntax;
  2047 
  2048 
  2049 *** HOLCF ***
  2050 
  2051 * removed "axioms" and "generated by" sections;
  2052 
  2053 * replaced "ops" section by extended "consts" section, which is capable of
  2054   handling the continuous function space "->" directly;
  2055 
  2056 * domain package:
  2057   . proves theorems immediately and stores them in the theory,
  2058   . creates hierachical name space,
  2059   . now uses normal mixfix annotations (instead of cinfix...),
  2060   . minor changes to some names and values (for consistency),
  2061   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2062   . separator between mutual domain defs: changed "," to "and",
  2063   . improved handling of sort constraints;  now they have to
  2064     appear on the left-hand side of the equations only;
  2065 
  2066 * fixed LAM <x,y,zs>.b syntax;
  2067 
  2068 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2069 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2070 
  2071 
  2072 *** FOL and ZF ***
  2073 
  2074 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2075   with `addloop' of the simplifier to faciliate case splitting in premises.
  2076 
  2077 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2078 in HOL, they strip ALL and --> from proved theorems;
  2079 
  2080 
  2081 
  2082 New in Isabelle94-8 (May 1997)
  2083 ------------------------------
  2084 
  2085 *** General Changes ***
  2086 
  2087 * new utilities to build / run / maintain Isabelle etc. (in parts
  2088 still somewhat experimental); old Makefiles etc. still functional;
  2089 
  2090 * new 'Isabelle System Manual';
  2091 
  2092 * INSTALL text, together with ./configure and ./build scripts;
  2093 
  2094 * reimplemented type inference for greater efficiency, better error
  2095 messages and clean internal interface;
  2096 
  2097 * prlim command for dealing with lots of subgoals (an easier way of
  2098 setting goals_limit);
  2099 
  2100 
  2101 *** Syntax ***
  2102 
  2103 * supports alternative (named) syntax tables (parser and pretty
  2104 printer); internal interface is provided by add_modesyntax(_i);
  2105 
  2106 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2107 be used in conjunction with the Isabelle symbol font; uses the
  2108 "symbols" syntax table;
  2109 
  2110 * added token_translation interface (may translate name tokens in
  2111 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2112 the current print_mode); IMPORTANT: user print translation functions
  2113 are responsible for marking newly introduced bounds
  2114 (Syntax.mark_boundT);
  2115 
  2116 * token translations for modes "xterm" and "xterm_color" that display
  2117 names in bold, underline etc. or colors (which requires a color
  2118 version of xterm);
  2119 
  2120 * infixes may now be declared with names independent of their syntax;
  2121 
  2122 * added typed_print_translation (like print_translation, but may
  2123 access type of constant);
  2124 
  2125 
  2126 *** Classical Reasoner ***
  2127 
  2128 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2129 some limitations.  Blast_tac...
  2130   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2131   + ignores elimination rules that don't have the correct format
  2132         (the conclusion MUST be a formula variable)
  2133   + ignores types, which can make HOL proofs fail
  2134   + rules must not require higher-order unification, e.g. apply_type in ZF
  2135     [message "Function Var's argument not a bound variable" relates to this]
  2136   + its proof strategy is more general but can actually be slower
  2137 
  2138 * substitution with equality assumptions no longer permutes other
  2139 assumptions;
  2140 
  2141 * minor changes in semantics of addafter (now called addaltern); renamed
  2142 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2143 (and access functions for it);
  2144 
  2145 * improved combination of classical reasoner and simplifier:
  2146   + functions for handling clasimpsets
  2147   + improvement of addss: now the simplifier is called _after_ the
  2148     safe steps.
  2149   + safe variant of addss called addSss: uses safe simplifications
  2150     _during_ the safe steps. It is more complete as it allows multiple
  2151     instantiations of unknowns (e.g. with slow_tac).
  2152 
  2153 *** Simplifier ***
  2154 
  2155 * added interface for simplification procedures (functions that
  2156 produce *proven* rewrite rules on the fly, depending on current
  2157 redex);
  2158 
  2159 * ordering on terms as parameter (used for ordered rewriting);
  2160 
  2161 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2162 
  2163 * the solver is now split into a safe and an unsafe part.
  2164 This should be invisible for the normal user, except that the
  2165 functions setsolver and addsolver have been renamed to setSolver and
  2166 addSolver; added safe_asm_full_simp_tac;
  2167 
  2168 
  2169 *** HOL ***
  2170 
  2171 * a generic induction tactic `induct_tac' which works for all datatypes and
  2172 also for type `nat';
  2173 
  2174 * a generic case distinction tactic `exhaust_tac' which works for all
  2175 datatypes and also for type `nat';
  2176 
  2177 * each datatype comes with a function `size';
  2178 
  2179 * patterns in case expressions allow tuple patterns as arguments to
  2180 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2181 
  2182 * primrec now also works with type nat;
  2183 
  2184 * recdef: a new declaration form, allows general recursive functions to be
  2185 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2186 
  2187 * the constant for negation has been renamed from "not" to "Not" to
  2188 harmonize with FOL, ZF, LK, etc.;
  2189 
  2190 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2191 infinite lists;
  2192 
  2193 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2194 
  2195 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2196 problems in commutative rings, using axiomatic type classes for + and *;
  2197 
  2198 * more examples in HOL/MiniML and HOL/Auth;
  2199 
  2200 * more default rewrite rules for quantifiers, union/intersection;
  2201 
  2202 * a new constant `arbitrary == @x.False';
  2203 
  2204 * HOLCF/IOA replaces old HOL/IOA;
  2205 
  2206 * HOLCF changes: derived all rules and arities
  2207   + axiomatic type classes instead of classes
  2208   + typedef instead of faking type definitions
  2209   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2210   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2211   + eliminated the types void, one, tr
  2212   + use unit lift and bool lift (with translations) instead of one and tr
  2213   + eliminated blift from Lift3.thy (use Def instead of blift)
  2214   all eliminated rules are derived as theorems --> no visible changes ;
  2215 
  2216 
  2217 *** ZF ***
  2218 
  2219 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2220 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2221 as ZF_cs addSIs [equalityI];
  2222 
  2223 
  2224 
  2225 New in Isabelle94-7 (November 96)
  2226 ---------------------------------
  2227 
  2228 * allowing negative levels (as offsets) in prlev and choplev;
  2229 
  2230 * super-linear speedup for large simplifications;
  2231 
  2232 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2233 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2234 FAIL); can suppress it using the command Delsimps (ex_simps @
  2235 all_simps); De Morgan laws are also now included, by default;
  2236 
  2237 * improved printing of ==>  :  ~:
  2238 
  2239 * new object-logic "Sequents" adds linear logic, while replacing LK
  2240 and Modal (thanks to Sara Kalvala);
  2241 
  2242 * HOL/Auth: correctness proofs for authentication protocols;
  2243 
  2244 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2245 examples on HOL/Auth);
  2246 
  2247 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2248 the rewriter and classical reasoner simultaneously;
  2249 
  2250 * function uresult no longer returns theorems in "standard" format;
  2251 regain previous version by: val uresult = standard o uresult;
  2252 
  2253 
  2254 
  2255 New in Isabelle94-6
  2256 -------------------
  2257 
  2258 * oracles -- these establish an interface between Isabelle and trusted
  2259 external reasoners, which may deliver results as theorems;
  2260 
  2261 * proof objects (in particular record all uses of oracles);
  2262 
  2263 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2264 
  2265 * "constdefs" section in theory files;
  2266 
  2267 * "primrec" section (HOL) no longer requires names;
  2268 
  2269 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2270 
  2271 
  2272 
  2273 New in Isabelle94-5
  2274 -------------------
  2275 
  2276 * reduced space requirements;
  2277 
  2278 * automatic HTML generation from theories;
  2279 
  2280 * theory files no longer require "..." (quotes) around most types;
  2281 
  2282 * new examples, including two proofs of the Church-Rosser theorem;
  2283 
  2284 * non-curried (1994) version of HOL is no longer distributed;
  2285 
  2286 
  2287 
  2288 New in Isabelle94-4
  2289 -------------------
  2290 
  2291 * greatly reduced space requirements;
  2292 
  2293 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2294 
  2295 * searchable theorem database (see the section "Retrieving theorems" on
  2296 page 8 of the Reference Manual);
  2297 
  2298 * new examples, including Grabczewski's monumental case study of the
  2299 Axiom of Choice;
  2300 
  2301 * The previous version of HOL renamed to Old_HOL;
  2302 
  2303 * The new version of HOL (previously called CHOL) uses a curried syntax
  2304 for functions.  Application looks like f a b instead of f(a,b);
  2305 
  2306 * Mutually recursive inductive definitions finally work in HOL;
  2307 
  2308 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2309 translates to the operator "split";
  2310 
  2311 
  2312 
  2313 New in Isabelle94-3
  2314 -------------------
  2315 
  2316 * new infix operator, addss, allowing the classical reasoner to
  2317 perform simplification at each step of its search.  Example:
  2318         fast_tac (cs addss ss)
  2319 
  2320 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2321 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2322 look like (a,b) instead of <a,b>;
  2323 
  2324 * PLEASE NOTE: CHOL will eventually replace HOL!
  2325 
  2326 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2327 It translates to the operator "split".  A new theory of integers is available;
  2328 
  2329 * In ZF, integer numerals now denote two's-complement binary integers.
  2330 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2331 
  2332 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2333 of the Axiom of Choice;
  2334 
  2335 
  2336 
  2337 New in Isabelle94-2
  2338 -------------------
  2339 
  2340 * Significantly faster resolution;
  2341 
  2342 * the different sections in a .thy file can now be mixed and repeated
  2343 freely;
  2344 
  2345 * Database of theorems for FOL, HOL and ZF.  New
  2346 commands including qed, qed_goal and bind_thm store theorems in the database.
  2347 
  2348 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2349 a given theory (thms_of), or find out what theory a theorem was proved in
  2350 (theory_of_thm);
  2351 
  2352 * Bugs fixed in the inductive definition and datatype packages;
  2353 
  2354 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2355 and HOL_dup_cs obsolete;
  2356 
  2357 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2358 have been removed;
  2359 
  2360 * Simpler definition of function space in ZF;
  2361 
  2362 * new results about cardinal and ordinal arithmetic in ZF;
  2363 
  2364 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2365 types;
  2366 
  2367 
  2368 $Id$