NEWS
author ballarin
Wed Apr 30 18:30:57 2003 +0200 (2003-04-30)
changeset 13938 b033b53d0c1e
parent 13899 12c7029d278b
child 13953 65b76920e108
permissions -rw-r--r--
Simplifier: congruence rule update.
     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   - You can limit the number of recursive invocations of the simplifier
    41     during conditional rewriting (where the simplifie tries to solve the
    42     conditions before applying the rewrite rule):
    43     ML "simp_depth_limit := n"
    44     where n is an integer. Thus you can force termination where previously
    45     the simplifier would diverge.
    46 
    47   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
    48 
    49   - No longer aborts on failed congruence proof.  Instead, the
    50     congruence is ignored.
    51 
    52 * Pure: The main goal of the proof state is no longer shown by default, only
    53 the subgoals. This behaviour is controlled by a new flag.
    54    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
    55 (ML: Proof.show_main_goal).
    56 
    57 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
    58 rules whose conclusion matches subgoal 1:
    59       PG menu: Isabelle/Isar -> Show me -> matching rules
    60 The rules are ordered by how closely they match the subgoal.
    61 In particular, rules that solve a subgoal outright are displayed first
    62 (or rather last, the way they are printed).
    63 (ML: ProofGeneral.print_intros())
    64 
    65 * Pure: New flag trace_unify_fail causes unification to print
    66 diagnostic information (PG: in trace buffer) when it fails. This is
    67 useful for figuring out why single step proofs like rule, erule or
    68 assumption failed.
    69 
    70 * Pure: Locale specifications now produce predicate definitions
    71 according to the body of text (covering assumptions modulo local
    72 definitions); predicate "loc_axioms" covers newly introduced text,
    73 while "loc" is cumulative wrt. all included locale expressions; the
    74 latter view is presented only on export into the global theory
    75 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    76 on the old view without predicates;
    77 
    78 * Pure: predefined locales "var" and "struct" are useful for sharing
    79 parameters (as in CASL, for example); just specify something like
    80 ``var x + var y + struct M'' as import;
    81 
    82 * Pure: improved thms_containing: proper indexing of facts instead of
    83 raw theorems; check validity of results wrt. current name space;
    84 include local facts of proof configuration (also covers active
    85 locales), cover fixed variables in index; may use "_" in term
    86 specification; an optional limit for the number of printed facts may
    87 be given (the default is 40);
    88 
    89 * Pure: disallow duplicate fact bindings within new-style theory files
    90 (batch-mode only);
    91 
    92 * Provers: improved induct method: assumptions introduced by case
    93 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    94 the goal statement); "foo" still refers to all facts collectively;
    95 
    96 * Provers: the function blast.overloaded has been removed: all constants
    97 are regarded as potentially overloaded, which improves robustness in exchange
    98 for slight decrease in efficiency;
    99 
   100 * Provers/linorder: New generic prover for transitivity reasoning over
   101 linear orders.  Note: this prover is not efficient!
   102 
   103 * Isar: preview of problems to finish 'show' now produce an error
   104 rather than just a warning (in interactive mode);
   105 
   106 
   107 *** HOL ***
   108 
   109 * arith(_tac)
   110 
   111  - Produces a counter example if it cannot prove a goal.
   112    Note that the counter example may be spurious if the goal is not a formula
   113    of quantifier-free linear arithmetic.
   114    In ProofGeneral the counter example appears in the trace buffer.
   115 
   116  - Knows about div k and mod k where k is a numeral of type nat or int.
   117 
   118  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   119    linear arithmetic fails. This takes account of quantifiers and divisibility.
   120    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   121 
   122 * simp's arithmetic capabilities have been enhanced a bit: it now
   123 takes ~= in premises into account (by performing a case split);
   124 
   125 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   126 are distributed over a sum of terms;
   127 
   128 * New tactic "trans_tac" and method "trans" instantiate
   129 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   130 "<=", "<" and "="). 
   131 
   132 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   133 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   134 
   135 * 'typedef' command has new option "open" to suppress the set
   136 definition;
   137 
   138 * functions Min and Max on finite sets have been introduced (theory
   139 Finite_Set);
   140 
   141 * attribute [symmetric] now works for relations as well; it turns
   142 (x,y) : R^-1 into (y,x) : R, and vice versa;
   143 
   144 * induct over a !!-quantified statement (say !!x1..xn):
   145   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   146 
   147 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   148 %x. None. Warning: empty_def now refers to the previously hidden definition
   149 of the empty set.
   150 
   151 * Real/HahnBanach: updated and adapted to locales;
   152 
   153 * GroupTheory: converted to Isar theories, using locales with implicit
   154 structures.  Also a new, experimental summation operator for abelian groups;
   155 
   156 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad, Gray and
   157 Kramer);
   158 
   159 * UNITY: added the Meier-Sanders theory of progress sets;
   160 
   161 
   162 *** ZF ***
   163 
   164 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   165 universe, etc.);
   166 
   167 * Main ZF: virtually all theories converted to new-style format;
   168 
   169 
   170 *** ML ***
   171 
   172 * Pure: Tactic.prove provides sane interface for internal proofs;
   173 omits the infamous "standard" operation, so this is more appropriate
   174 than prove_goalw_cterm in many situations (e.g. in simprocs);
   175 
   176 * Pure: improved error reporting of simprocs;
   177 
   178 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   179 up simprocs;
   180 
   181 
   182 
   183 New in Isabelle2002 (March 2002)
   184 --------------------------------
   185 
   186 *** Document preparation ***
   187 
   188 * greatly simplified document preparation setup, including more
   189 graceful interpretation of isatool usedir -i/-d/-D options, and more
   190 instructive isatool mkdir; users should basically be able to get
   191 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   192 users may run a separate document processing stage manually like this:
   193 "isatool usedir -D output HOL Test && isatool document Test/output";
   194 
   195 * theory dependency graph may now be incorporated into documents;
   196 isatool usedir -g true will produce session_graph.eps/.pdf for use
   197 with \includegraphics of LaTeX;
   198 
   199 * proper spacing of consecutive markup elements, especially text
   200 blocks after section headings;
   201 
   202 * support bold style (for single symbols only), input syntax is like
   203 this: "\<^bold>\<alpha>" or "\<^bold>A";
   204 
   205 * \<bullet> is now output as bold \cdot by default, which looks much
   206 better in printed text;
   207 
   208 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   209 note that these symbols are currently unavailable in Proof General /
   210 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   211 
   212 * isatool latex no longer depends on changed TEXINPUTS, instead
   213 isatool document copies the Isabelle style files to the target
   214 location;
   215 
   216 
   217 *** Isar ***
   218 
   219 * Pure/Provers: improved proof by cases and induction;
   220   - 'case' command admits impromptu naming of parameters (such as
   221     "case (Suc n)");
   222   - 'induct' method divinates rule instantiation from the inductive
   223     claim; no longer requires excessive ?P bindings for proper
   224     instantiation of cases;
   225   - 'induct' method properly enumerates all possibilities of set/type
   226     rules; as a consequence facts may be also passed through *type*
   227     rules without further ado;
   228   - 'induct' method now derives symbolic cases from the *rulified*
   229     rule (before it used to rulify cases stemming from the internal
   230     atomized version); this means that the context of a non-atomic
   231     statement becomes is included in the hypothesis, avoiding the
   232     slightly cumbersome show "PROP ?case" form;
   233   - 'induct' may now use elim-style induction rules without chaining
   234     facts, using ``missing'' premises from the goal state; this allows
   235     rules stemming from inductive sets to be applied in unstructured
   236     scripts, while still benefitting from proper handling of non-atomic
   237     statements; NB: major inductive premises need to be put first, all
   238     the rest of the goal is passed through the induction;
   239   - 'induct' proper support for mutual induction involving non-atomic
   240     rule statements (uses the new concept of simultaneous goals, see
   241     below);
   242   - append all possible rule selections, but only use the first
   243     success (no backtracking);
   244   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   245   - undeclared rule case names default to numbers 1, 2, 3, ...;
   246   - added 'print_induct_rules' (covered by help item in recent Proof
   247     General versions);
   248   - moved induct/cases attributes to Pure, methods to Provers;
   249   - generic method setup instantiated for FOL and HOL;
   250 
   251 * Pure: support multiple simultaneous goal statements, for example
   252 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   253 meta-level mechanism, this acts as if several individual goals had
   254 been stated separately; in particular common proof methods need to be
   255 repeated in order to cover all claims; note that a single elimination
   256 step is *not* sufficient to establish the two conjunctions, so this
   257 fails:
   258 
   259   assume "A & B" then have A and B ..   (*".." fails*)
   260 
   261 better use "obtain" in situations as above; alternative refer to
   262 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   263 
   264 * Pure: proper integration with ``locales''; unlike the original
   265 version by Florian Kammüller, Isar locales package high-level proof
   266 contexts rather than raw logical ones (e.g. we admit to include
   267 attributes everywhere); operations on locales include merge and
   268 rename; support for implicit arguments (``structures''); simultaneous
   269 type-inference over imports and text; see also HOL/ex/Locales.thy for
   270 some examples;
   271 
   272 * Pure: the following commands have been ``localized'', supporting a
   273 target locale specification "(in name)": 'lemma', 'theorem',
   274 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   275 stored both within the locale and at the theory level (exported and
   276 qualified by the locale name);
   277 
   278 * Pure: theory goals may now be specified in ``long'' form, with
   279 ad-hoc contexts consisting of arbitrary locale elements. for example
   280 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   281 definitions may be given, too); the result is a meta-level rule with
   282 the context elements being discharged in the obvious way;
   283 
   284 * Pure: new proof command 'using' allows to augment currently used
   285 facts after a goal statement ('using' is syntactically analogous to
   286 'apply', but acts on the goal's facts only); this allows chained facts
   287 to be separated into parts given before and after a claim, as in
   288 ``from a and b have C using d and e <proof>'';
   289 
   290 * Pure: renamed "antecedent" case to "rule_context";
   291 
   292 * Pure: new 'judgment' command records explicit information about the
   293 object-logic embedding (used by several tools internally); no longer
   294 use hard-wired "Trueprop";
   295 
   296 * Pure: added 'corollary' command;
   297 
   298 * Pure: fixed 'token_translation' command;
   299 
   300 * Pure: removed obsolete 'exported' attribute;
   301 
   302 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   303 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   304 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   305 
   306 * Pure: method 'atomize' presents local goal premises as object-level
   307 statements (atomic meta-level propositions); setup controlled via
   308 rewrite rules declarations of 'atomize' attribute; example
   309 application: 'induct' method with proper rule statements in improper
   310 proof *scripts*;
   311 
   312 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   313 now consider the syntactic context of assumptions, giving a better
   314 chance to get type-inference of the arguments right (this is
   315 especially important for locales);
   316 
   317 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   318 mode;
   319 
   320 * Pure/obtain: the formal conclusion "thesis", being marked as
   321 ``internal'', may no longer be reference directly in the text;
   322 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   323 situations;
   324 
   325 * Pure: generic 'sym' attribute which declares a rule both as pure
   326 'elim?' and for the 'symmetric' operation;
   327 
   328 * Pure: marginal comments ``--'' may now occur just anywhere in the
   329 text; the fixed correlation with particular command syntax has been
   330 discontinued;
   331 
   332 * Pure: new method 'rules' is particularly well-suited for proof
   333 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   334 but often produces more compact proof terms with less detours;
   335 
   336 * Pure/Provers/classical: simplified integration with pure rule
   337 attributes and methods; the classical "intro?/elim?/dest?"
   338 declarations coincide with the pure ones; the "rule" method no longer
   339 includes classically swapped intros; "intro" and "elim" methods no
   340 longer pick rules from the context; also got rid of ML declarations
   341 AddXIs/AddXEs/AddXDs; all of this has some potential for
   342 INCOMPATIBILITY;
   343 
   344 * Provers/classical: attribute 'swapped' produces classical inversions
   345 of introduction rules;
   346 
   347 * Provers/simplifier: 'simplified' attribute may refer to explicit
   348 rules instead of full simplifier context; 'iff' attribute handles
   349 conditional rules;
   350 
   351 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   352 
   353 * HOL: 'recdef' now fails on unfinished automated proofs, use
   354 "(permissive)" option to recover old behavior;
   355 
   356 * HOL: 'inductive' no longer features separate (collective) attributes
   357 for 'intros' (was found too confusing);
   358 
   359 * HOL: properly declared induction rules less_induct and
   360 wf_induct_rule;
   361 
   362 
   363 *** HOL ***
   364 
   365 * HOL: moved over to sane numeral syntax; the new policy is as
   366 follows:
   367 
   368   - 0 and 1 are polymorphic constants, which are defined on any
   369   numeric type (nat, int, real etc.);
   370 
   371   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   372   binary representation internally;
   373 
   374   - type nat has special constructor Suc, and generally prefers Suc 0
   375   over 1::nat and Suc (Suc 0) over 2::nat;
   376 
   377 This change may cause significant problems of INCOMPATIBILITY; here
   378 are some hints on converting existing sources:
   379 
   380   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   381   entities, so expressions involving "-" (unary or binary minus) need
   382   to be spaced properly;
   383 
   384   - existing occurrences of "1" may need to be constraint "1::nat" or
   385   even replaced by Suc 0; similar for old "2";
   386 
   387   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   388 
   389   - remove all special provisions on numerals in proofs;
   390 
   391 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   392 representation (depends on bin_arith_simps in the default context);
   393 
   394 * HOL: symbolic syntax for x^2 (numeral 2);
   395 
   396 * HOL: the class of all HOL types is now called "type" rather than
   397 "term"; INCOMPATIBILITY, need to adapt references to this type class
   398 in axclass/classes, instance/arities, and (usually rare) occurrences
   399 in typings (of consts etc.); internally the class is called
   400 "HOL.type", ML programs should refer to HOLogic.typeS;
   401 
   402 * HOL/record package improvements:
   403   - new derived operations "fields" to build a partial record section,
   404     "extend" to promote a fixed record to a record scheme, and
   405     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   406     declared as simp by default;
   407   - shared operations ("more", "fields", etc.) now need to be always
   408     qualified) --- potential INCOMPATIBILITY;
   409   - removed "make_scheme" operations (use "make" with "extend") --
   410     INCOMPATIBILITY;
   411   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   412   - provides cases/induct rules for use with corresponding Isar
   413     methods (for concrete records, record schemes, concrete more
   414     parts, and schematic more parts -- in that order);
   415   - internal definitions directly based on a light-weight abstract
   416     theory of product types over typedef rather than datatype;
   417 
   418 * HOL: generic code generator for generating executable ML code from
   419 specifications; specific support for HOL constructs such as inductive
   420 datatypes and sets, as well as recursive functions; can be invoked
   421 via 'generate_code' theory section;
   422 
   423 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   424 
   425 * HOL: consolidated and renamed several theories.  In particular:
   426 	Ord.thy has been absorbed into HOL.thy
   427 	String.thy has been absorbed into List.thy
   428  
   429 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   430 (beware of argument permutation!);
   431 
   432 * HOL: linorder_less_split superseded by linorder_cases;
   433 
   434 * HOL/List: "nodups" renamed to "distinct";
   435 
   436 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   437 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   438   - Ex_def has changed, now need to use some_eq_ex
   439 
   440 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   441 in this (rare) case use:
   442 
   443   delSWrapper "split_all_tac"
   444   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   445 
   446 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   447 MAY FAIL;
   448 
   449 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   450 Isabelle's type classes, ^ on functions and relations has too general
   451 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   452 necessary to attach explicit type constraints;
   453 
   454 * HOL/Relation: the prefix name of the infix "O" has been changed from
   455 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   456 renamed accordingly (eg "compI" -> "rel_compI").
   457 
   458 * HOL: syntax translations now work properly with numerals and records
   459 expressions;
   460 
   461 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   462 of "lam" -- INCOMPATIBILITY;
   463 
   464 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   465 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   466 renamed "Product_Type.unit";
   467 
   468 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   469 
   470 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   471 the "cases" method);
   472 
   473 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   474 Florian Kammüller);
   475 
   476 * HOL/IMP: updated and converted to new-style theory format; several
   477 parts turned into readable document, with proper Isar proof texts and
   478 some explanations (by Gerwin Klein);
   479 
   480 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   481 
   482 * HOL-Hyperreal is now a logic image;
   483 
   484 
   485 *** HOLCF ***
   486 
   487 * Isar: consts/constdefs supports mixfix syntax for continuous
   488 operations;
   489 
   490 * Isar: domain package adapted to new-style theory format, e.g. see
   491 HOLCF/ex/Dnat.thy;
   492 
   493 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   494 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   495 lift.induct_tac, always use UU instead of Undef;
   496 
   497 * HOLCF/IMP: updated and converted to new-style theory;
   498 
   499 
   500 *** ZF ***
   501 
   502 * Isar: proper integration of logic-specific tools and packages,
   503 including theory commands '(co)inductive', '(co)datatype',
   504 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   505 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   506 
   507 * theory Main no longer includes AC; for the Axiom of Choice, base
   508 your theory on Main_ZFC;
   509 
   510 * the integer library now covers quotients and remainders, with many
   511 laws relating division to addition, multiplication, etc.;
   512 
   513 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   514 typeless version of the formalism;
   515 
   516 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   517 format;
   518 
   519 * ZF/Induct: new directory for examples of inductive definitions,
   520 including theory Multiset for multiset orderings; converted to
   521 new-style theory format;
   522 
   523 * ZF: many new theorems about lists, ordinals, etc.;
   524 
   525 
   526 *** General ***
   527 
   528 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   529 variable proof controls level of detail: 0 = no proofs (only oracle
   530 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   531 also ref manual for further ML interfaces;
   532 
   533 * Pure/axclass: removed obsolete ML interface
   534 goal_subclass/goal_arity;
   535 
   536 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   537 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   538 separate tokens, so expressions involving minus need to be spaced
   539 properly;
   540 
   541 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   542 rather than "infixl" or "infixr";
   543 
   544 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   545 sort constraint specifications in type inference; e.g. "x::_::foo"
   546 ensures that the type of "x" is of sort "foo" (but not necessarily a
   547 type variable);
   548 
   549 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   550 control output of nested => (types); the default behavior is
   551 "type_brackets";
   552 
   553 * Pure/syntax: builtin parse translation for "_constify" turns valued
   554 tokens into AST constants;
   555 
   556 * Pure/syntax: prefer later declarations of translations and print
   557 translation functions; potential INCOMPATIBILITY: need to reverse
   558 multiple declarations for same syntax element constant;
   559 
   560 * Pure/show_hyps reset by default (in accordance to existing Isar
   561 practice);
   562 
   563 * Provers/classical: renamed addaltern to addafter, addSaltern to
   564 addSafter;
   565 
   566 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   567 as well;
   568 
   569 * system: tested support for MacOS X; should be able to get Isabelle +
   570 Proof General to work in a plain Terminal after installing Poly/ML
   571 (e.g. from the Isabelle distribution area) and GNU bash alone
   572 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   573 support requires further installations, e.g. from
   574 http://fink.sourceforge.net/);
   575 
   576 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   577 
   578 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   579 of 40 MB), cf. ML_OPTIONS;
   580 
   581 * system: Proof General keywords specification is now part of the
   582 Isabelle distribution (see etc/isar-keywords.el);
   583 
   584 * system: support for persistent Proof General sessions (refrain from
   585 outdating all loaded theories on startup); user may create writable
   586 logic images like this: ``isabelle -q HOL Test'';
   587 
   588 * system: smart selection of Isabelle process versus Isabelle
   589 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   590 run both "isabelle" and "Isabelle" even if file names are badly
   591 damaged (executable inspects the case of the first letter of its own
   592 name); added separate "isabelle-process" and "isabelle-interface";
   593 
   594 * system: refrain from any attempt at filtering input streams; no
   595 longer support ``8bit'' encoding of old isabelle font, instead proper
   596 iso-latin characters may now be used; the related isatools
   597 "symbolinput" and "nonascii" have disappeared as well;
   598 
   599 * system: removed old "xterm" interface (the print modes "xterm" and
   600 "xterm_color" are still available for direct use in a suitable
   601 terminal);
   602 
   603 
   604 
   605 New in Isabelle99-2 (February 2001)
   606 -----------------------------------
   607 
   608 *** Overview of INCOMPATIBILITIES ***
   609 
   610 * HOL: please note that theories in the Library and elsewhere often use the
   611 new-style (Isar) format; to refer to their theorems in an ML script you must
   612 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   613 
   614 * HOL: inductive package no longer splits induction rule aggressively,
   615 but only as far as specified by the introductions given; the old
   616 format may be recovered via ML function complete_split_rule or attribute
   617 'split_rule (complete)';
   618 
   619 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   620 gfp_Tarski to gfp_unfold;
   621 
   622 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   623 
   624 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   625 relation); infix "^^" has been renamed "``"; infix "``" has been
   626 renamed "`"; "univalent" has been renamed "single_valued";
   627 
   628 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   629 operation;
   630 
   631 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   632 
   633 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   634 
   635 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   636 consequence, it is no longer monotonic wrt. the local goal context
   637 (which is now passed through the inductive cases);
   638 
   639 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   640 \<gg> to \<ggreater>;
   641 
   642 
   643 *** Document preparation ***
   644 
   645 * \isabellestyle{NAME} selects version of Isabelle output (currently
   646 available: are "it" for near math-mode best-style output, "sl" for
   647 slanted text style, and "tt" for plain type-writer; if no
   648 \isabellestyle command is given, output is according to slanted
   649 type-writer);
   650 
   651 * support sub/super scripts (for single symbols only), input syntax is
   652 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   653 
   654 * some more standard symbols; see Appendix A of the system manual for
   655 the complete list of symbols defined in isabellesym.sty;
   656 
   657 * improved isabelle style files; more abstract symbol implementation
   658 (should now use \isamath{...} and \isatext{...} in custom symbol
   659 definitions);
   660 
   661 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   662 state; Note that presentation of goal states does not conform to
   663 actual human-readable proof documents.  Please do not include goal
   664 states into document output unless you really know what you are doing!
   665 
   666 * proper indentation of antiquoted output with proportional LaTeX
   667 fonts;
   668 
   669 * no_document ML operator temporarily disables LaTeX document
   670 generation;
   671 
   672 * isatool unsymbolize tunes sources for plain ASCII communication;
   673 
   674 
   675 *** Isar ***
   676 
   677 * Pure: Isar now suffers initial goal statements to contain unbound
   678 schematic variables (this does not conform to actual readable proof
   679 documents, due to unpredictable outcome and non-compositional proof
   680 checking); users who know what they are doing may use schematic goals
   681 for Prolog-style synthesis of proven results;
   682 
   683 * Pure: assumption method (an implicit finishing) now handles actual
   684 rules as well;
   685 
   686 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   687 initial goal, declare "that" only as Pure intro (only for single
   688 steps); the "that" rule assumption may now be involved in implicit
   689 finishing, thus ".." becomes a feasible for trivial obtains;
   690 
   691 * Pure: default proof step now includes 'intro_classes'; thus trivial
   692 instance proofs may be performed by "..";
   693 
   694 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   695 statements as well;
   696 
   697 * Pure: more robust selection of calculational rules;
   698 
   699 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   700 rule (as well as the assumption rule);
   701 
   702 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   703 lemmas, using the graph browser tool;
   704 
   705 * Pure: predict failure of "show" in interactive mode;
   706 
   707 * Pure: 'thms_containing' now takes actual terms as arguments;
   708 
   709 * HOL: improved method 'induct' --- now handles non-atomic goals
   710 (potential INCOMPATIBILITY); tuned error handling;
   711 
   712 * HOL: cases and induct rules now provide explicit hints about the
   713 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   714 any remaining facts are inserted into the goal verbatim;
   715 
   716 * HOL: local contexts (aka cases) may now contain term bindings as
   717 well; the 'cases' and 'induct' methods new provide a ?case binding for
   718 the result to be shown in each case;
   719 
   720 * HOL: added 'recdef_tc' command;
   721 
   722 * isatool convert assists in eliminating legacy ML scripts;
   723 
   724 
   725 *** HOL ***
   726 
   727 * HOL/Library: a collection of generic theories to be used together
   728 with main HOL; the theory loader path already includes this directory
   729 by default; the following existing theories have been moved here:
   730 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   731 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   732 
   733 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   734 modelling and verification task performed in Isabelle/HOL +
   735 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   736 
   737 * HOL/Algebra: special summation operator SUM no longer exists, it has
   738 been replaced by setsum; infix 'assoc' now has priority 50 (like
   739 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   740 'domain', this makes the theory consistent with mathematical
   741 literature;
   742 
   743 * HOL basics: added overloaded operations "inverse" and "divide"
   744 (infix "/"), syntax for generic "abs" operation, generic summation
   745 operator \<Sum>;
   746 
   747 * HOL/typedef: simplified package, provide more useful rules (see also
   748 HOL/subset.thy);
   749 
   750 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   751 now expressed as a proper nested rule (old-style tactic scripts may
   752 require atomize_strip_tac to cope with non-atomic premises);
   753 
   754 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   755 to "split_conv" (old name still available for compatibility);
   756 
   757 * HOL: improved concrete syntax for strings (e.g. allows translation
   758 rules with string literals);
   759 
   760 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   761  and Fleuriot's mechanization of analysis, including the transcendental
   762  functions for the reals;
   763 
   764 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   765 
   766 
   767 *** CTT ***
   768 
   769 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   770 "lam" is displayed as TWO lambda-symbols
   771 
   772 * CTT: theory Main now available, containing everything (that is, Bool
   773 and Arith);
   774 
   775 
   776 *** General ***
   777 
   778 * Pure: the Simplifier has been implemented properly as a derived rule
   779 outside of the actual kernel (at last!); the overall performance
   780 penalty in practical applications is about 50%, while reliability of
   781 the Isabelle inference kernel has been greatly improved;
   782 
   783 * print modes "brackets" and "no_brackets" control output of nested =>
   784 (types) and ==> (props); the default behaviour is "brackets";
   785 
   786 * Provers: fast_tac (and friends) now handle actual object-logic rules
   787 as assumptions as well;
   788 
   789 * system: support Poly/ML 4.0;
   790 
   791 * system: isatool install handles KDE version 1 or 2;
   792 
   793 
   794 
   795 New in Isabelle99-1 (October 2000)
   796 ----------------------------------
   797 
   798 *** Overview of INCOMPATIBILITIES ***
   799 
   800 * HOL: simplification of natural numbers is much changed; to partly
   801 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   802 issue the following ML commands:
   803 
   804   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   805   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   806 
   807 * HOL: simplification no longer dives into case-expressions; this is
   808 controlled by "t.weak_case_cong" for each datatype t;
   809 
   810 * HOL: nat_less_induct renamed to less_induct;
   811 
   812 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   813 fixsome to patch .thy and .ML sources automatically;
   814 
   815   select_equality  -> some_equality
   816   select_eq_Ex     -> some_eq_ex
   817   selectI2EX       -> someI2_ex
   818   selectI2         -> someI2
   819   selectI          -> someI
   820   select1_equality -> some1_equality
   821   Eps_sym_eq       -> some_sym_eq_trivial
   822   Eps_eq           -> some_eq_trivial
   823 
   824 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   825 
   826 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   827 instead);
   828 
   829 * HOL: the recursion equations generated by 'recdef' are now called
   830 f.simps instead of f.rules;
   831 
   832 * HOL: qed_spec_mp now also handles bounded ALL as well;
   833 
   834 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   835 sometimes be needed;
   836 
   837 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   838 
   839 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   840 
   841 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   842 product is now "<*>" instead of "Times"; the lexicographic product is
   843 now "<*lex*>" instead of "**";
   844 
   845 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   846 of main HOL, but was unused); better use HOL's datatype package;
   847 
   848 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   849 the old syntax may be recovered as follows:
   850 
   851   syntax (symbols)
   852     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   853       (infixl "\\<oplus>" 100)
   854 
   855 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   856 
   857 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   858 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   859 internally;
   860 
   861 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   862 changed from A/r to A//r;
   863 
   864 * ZF: new treatment of arithmetic (nat & int) may break some old
   865 proofs;
   866 
   867 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   868 rulify -> rule_format, elimify -> elim_format, ...);
   869 
   870 * Isar/Provers: intro/elim/dest attributes changed; renamed
   871 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   872 should have to change intro!! to intro? only); replaced "delrule" by
   873 "rule del";
   874 
   875 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   876 
   877 * Provers: strengthened force_tac by using new first_best_tac;
   878 
   879 * LaTeX document preparation: several changes of isabelle.sty (see
   880 lib/texinputs);
   881 
   882 
   883 *** Document preparation ***
   884 
   885 * formal comments (text blocks etc.) in new-style theories may now
   886 contain antiquotations of thm/prop/term/typ/text to be presented
   887 according to latex print mode; concrete syntax is like this:
   888 @{term[show_types] "f(x) = a + x"};
   889 
   890 * isatool mkdir provides easy setup of Isabelle session directories,
   891 including proper document sources;
   892 
   893 * generated LaTeX sources are now deleted after successful run
   894 (isatool document -c); may retain a copy somewhere else via -D option
   895 of isatool usedir;
   896 
   897 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   898 style files, achieving self-contained LaTeX sources and simplifying
   899 LaTeX debugging;
   900 
   901 * old-style theories now produce (crude) LaTeX output as well;
   902 
   903 * browser info session directories are now self-contained (may be put
   904 on WWW server seperately); improved graphs of nested sessions; removed
   905 graph for 'all sessions';
   906 
   907 * several improvements in isabelle style files; \isabellestyle{it}
   908 produces fake math mode output; \isamarkupheader is now \section by
   909 default; see lib/texinputs/isabelle.sty etc.;
   910 
   911 
   912 *** Isar ***
   913 
   914 * Isar/Pure: local results and corresponding term bindings are now
   915 subject to Hindley-Milner polymorphism (similar to ML); this
   916 accommodates incremental type-inference very nicely;
   917 
   918 * Isar/Pure: new derived language element 'obtain' supports
   919 generalized existence reasoning;
   920 
   921 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   922 support accumulation of results, without applying any rules yet;
   923 useful to collect intermediate results without explicit name
   924 references, and for use with transitivity rules with more than 2
   925 premises;
   926 
   927 * Isar/Pure: scalable support for case-analysis type proofs: new
   928 'case' language element refers to local contexts symbolically, as
   929 produced by certain proof methods; internally, case names are attached
   930 to theorems as "tags";
   931 
   932 * Isar/Pure: theory command 'hide' removes declarations from
   933 class/type/const name spaces;
   934 
   935 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   936 indicate potential overloading;
   937 
   938 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   939 
   940 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   941 "{a,b,c}" instead of {a,b,c};
   942 
   943 * Isar/Pure now provides its own version of intro/elim/dest
   944 attributes; useful for building new logics, but beware of confusion
   945 with the version in Provers/classical;
   946 
   947 * Isar/Pure: the local context of (non-atomic) goals is provided via
   948 case name 'antecedent';
   949 
   950 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   951 to the current context is now done automatically);
   952 
   953 * Isar/Pure: theory command 'method_setup' provides a simple interface
   954 for definining proof methods in ML;
   955 
   956 * Isar/Provers: intro/elim/dest attributes changed; renamed
   957 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   958 most cases, one should have to change intro!! to intro? only);
   959 replaced "delrule" by "rule del";
   960 
   961 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   962 'symmetric' attribute (the latter supercedes [RS sym]);
   963 
   964 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   965 method modifier); 'simp' method: 'only:' modifier removes loopers as
   966 well (including splits);
   967 
   968 * Isar/Provers: Simplifier and Classical methods now support all kind
   969 of modifiers used in the past, including 'cong', 'iff', etc.
   970 
   971 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   972 of Simplifier and Classical reasoner);
   973 
   974 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   975 now support named cases; major packages (inductive, datatype, primrec,
   976 recdef) support case names and properly name parameters;
   977 
   978 * Isar/HOL: new transitivity rules for substitution in inequalities --
   979 monotonicity conditions are extracted to be proven at end of
   980 calculations;
   981 
   982 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   983 method anyway;
   984 
   985 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   986 split_if split_if_asm; datatype package provides theorems foo.splits =
   987 foo.split foo.split_asm for each datatype;
   988 
   989 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   990 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   991 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   992 use "(cases (simplified))" method in proper proof texts);
   993 
   994 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   995 
   996 * Isar: names of theorems etc. may be natural numbers as well;
   997 
   998 * Isar: 'pr' command: optional arguments for goals_limit and
   999 ProofContext.prems_limit; no longer prints theory contexts, but only
  1000 proof states;
  1001 
  1002 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1003 additional print modes to be specified; e.g. "pr(latex)" will print
  1004 proof state according to the Isabelle LaTeX style;
  1005 
  1006 * Isar: improved support for emulating tactic scripts, including proof
  1007 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1008 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1009 (for HOL datatypes);
  1010 
  1011 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1012 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1013 'proof method scripts' have to be in depth-first order;
  1014 
  1015 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1016 
  1017 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1018 should instead use individual commands for printing items
  1019 (print_commands, print_methods etc.);
  1020 
  1021 * Isar: added 'nothing' --- the empty list of theorems;
  1022 
  1023 
  1024 *** HOL ***
  1025 
  1026 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1027 corresponding virtual machine and a specification of its bytecode
  1028 verifier and a lightweight bytecode verifier, including proofs of
  1029 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1030 Cornelia Pusch (see also the homepage of project Bali at
  1031 http://isabelle.in.tum.de/Bali/);
  1032 
  1033 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1034 Clemens Ballarin;
  1035 
  1036 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1037 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1038 Rasmussen;
  1039 
  1040 * HOL/Lattice: fundamental concepts of lattice theory and order
  1041 structures, including duals, properties of bounds versus algebraic
  1042 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1043 Theorem for complete lattices etc.; may also serve as a demonstration
  1044 for abstract algebraic reasoning using axiomatic type classes, and
  1045 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1046 
  1047 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1048 von Oheimb;
  1049 
  1050 * HOL/IMPP: extension of IMP with local variables and mutually
  1051 recursive procedures, by David von Oheimb;
  1052 
  1053 * HOL/Lambda: converted into new-style theory and document;
  1054 
  1055 * HOL/ex/Multiquote: example of multiple nested quotations and
  1056 anti-quotations -- basically a generalized version of de-Bruijn
  1057 representation; very useful in avoiding lifting of operations;
  1058 
  1059 * HOL/record: added general record equality rule to simpset; fixed
  1060 select-update simplification procedure to handle extended records as
  1061 well; admit "r" as field name;
  1062 
  1063 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1064 other numeric types and also as the identity of groups, rings, etc.;
  1065 
  1066 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1067 Types nat and int belong to this axclass;
  1068 
  1069 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1070    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1071    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1072   two terms #m*u and #n*u are replaced by #(m+n)*u
  1073     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1074   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1075     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1076 
  1077 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1078 powerful prover for predicate logic but knows nothing of clasets; see
  1079 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1080 
  1081 * HOL: new version of "case_tac" subsumes both boolean case split and
  1082 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1083 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1084 
  1085 * HOL: simplification no longer dives into case-expressions: only the
  1086 selector expression is simplified, but not the remaining arms; to
  1087 enable full simplification of case-expressions for datatype t, you may
  1088 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1089 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1090 
  1091 * HOL/recdef: the recursion equations generated by 'recdef' for
  1092 function 'f' are now called f.simps instead of f.rules; if all
  1093 termination conditions are proved automatically, these simplification
  1094 rules are added to the simpset, as in primrec; rules may be named
  1095 individually as well, resulting in a separate list of theorems for
  1096 each equation;
  1097 
  1098 * HOL/While is a new theory that provides a while-combinator. It
  1099 permits the definition of tail-recursive functions without the
  1100 provision of a termination measure. The latter is necessary once the
  1101 invariant proof rule for while is applied.
  1102 
  1103 * HOL: new (overloaded) notation for the set of elements below/above
  1104 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1105 
  1106 * HOL: theorems impI, allI, ballI bound as "strip";
  1107 
  1108 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1109 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1110 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1111 
  1112 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1113 
  1114 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1115 main HOL, but was unused);
  1116 
  1117 * HOL: fewer consts declared as global (e.g. have to refer to
  1118 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1119 
  1120 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1121 in case of overlap with user translations (e.g. judgements over
  1122 tuples); (note that the underlying logical represenation is still
  1123 bogus);
  1124 
  1125 
  1126 *** ZF ***
  1127 
  1128 * ZF: simplification automatically cancels common terms in arithmetic
  1129 expressions over nat and int;
  1130 
  1131 * ZF: new treatment of nat to minimize type-checking: all operators
  1132 coerce their operands to a natural number using the function natify,
  1133 making the algebraic laws unconditional;
  1134 
  1135 * ZF: as above, for int: operators coerce their operands to an integer
  1136 using the function intify;
  1137 
  1138 * ZF: the integer library now contains many of the usual laws for the
  1139 orderings, including $<=, and monotonicity laws for $+ and $*;
  1140 
  1141 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1142 simplification;
  1143 
  1144 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1145 to the simplifier and classical reasoner simultaneously;
  1146 
  1147 
  1148 *** General ***
  1149 
  1150 * Provers: blast_tac now handles actual object-logic rules as
  1151 assumptions; note that auto_tac uses blast_tac internally as well;
  1152 
  1153 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1154 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1155 
  1156 * Provers: delrules now handles destruct rules as well (no longer need
  1157 explicit make_elim);
  1158 
  1159 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1160   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1161 use instead the strong form,
  1162   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1163 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1164 from destruct-rules;
  1165 
  1166 * Provers: Simplifier.easy_setup provides a fast path to basic
  1167 Simplifier setup for new object-logics;
  1168 
  1169 * Pure: AST translation rules no longer require constant head on LHS;
  1170 
  1171 * Pure: improved name spaces: ambiguous output is qualified; support
  1172 for hiding of names;
  1173 
  1174 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1175 XSYMBOL_HOME; no longer need to do manual configuration in most
  1176 situations;
  1177 
  1178 * system: compression of ML heaps images may now be controlled via -c
  1179 option of isabelle and isatool usedir (currently only observed by
  1180 Poly/ML);
  1181 
  1182 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1183 useful for remote X11);
  1184 
  1185 * system: provide TAGS file for Isabelle sources;
  1186 
  1187 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1188 order;
  1189 
  1190 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1191 timing flag supersedes proof_timing and Toplevel.trace;
  1192 
  1193 * ML: new combinators |>> and |>>> for incremental transformations
  1194 with secondary results (e.g. certain theory extensions):
  1195 
  1196 * ML: PureThy.add_defs gets additional argument to indicate potential
  1197 overloading (usually false);
  1198 
  1199 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1200 results;
  1201 
  1202 
  1203 
  1204 New in Isabelle99 (October 1999)
  1205 --------------------------------
  1206 
  1207 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1208 
  1209 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1210 are no longer simplified.  (This allows the simplifier to unfold recursive
  1211 functional programs.)  To restore the old behaviour, declare
  1212 
  1213     Delcongs [if_weak_cong];
  1214 
  1215 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1216 complement;
  1217 
  1218 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1219 
  1220 * HOL/datatype: mutual_induct_tac no longer exists --
  1221   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1222 
  1223 * HOL/typedef: fixed type inference for representing set; type
  1224 arguments now have to occur explicitly on the rhs as type constraints;
  1225 
  1226 * ZF: The con_defs part of an inductive definition may no longer refer
  1227 to constants declared in the same theory;
  1228 
  1229 * HOL, ZF: the function mk_cases, generated by the inductive
  1230 definition package, has lost an argument.  To simplify its result, it
  1231 uses the default simpset instead of a supplied list of theorems.
  1232 
  1233 * HOL/List: the constructors of type list are now Nil and Cons;
  1234 
  1235 * Simplifier: the type of the infix ML functions
  1236         setSSolver addSSolver setSolver addSolver
  1237 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1238 for packaging solvers. A solver is created via
  1239         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1240 where the string argument is only a comment.
  1241 
  1242 
  1243 *** Proof tools ***
  1244 
  1245 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1246 decision procedure for linear arithmetic. Currently it is used for
  1247 types `nat', `int', and `real' in HOL (see below); it can, should and
  1248 will be instantiated for other types and logics as well.
  1249 
  1250 * The simplifier now accepts rewrite rules with flexible heads, eg
  1251      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1252   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1253   matching.
  1254 
  1255 
  1256 *** General ***
  1257 
  1258 * New Isabelle/Isar subsystem provides an alternative to traditional
  1259 tactical theorem proving; together with the ProofGeneral/isar user
  1260 interface it offers an interactive environment for developing human
  1261 readable proof documents (Isar == Intelligible semi-automated
  1262 reasoning); for further information see isatool doc isar-ref,
  1263 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1264 
  1265 * improved and simplified presentation of theories: better HTML markup
  1266 (including colors), graph views in several sizes; isatool usedir now
  1267 provides a proper interface for user theories (via -P option); actual
  1268 document preparation based on (PDF)LaTeX is available as well (for
  1269 new-style theories only); see isatool doc system for more information;
  1270 
  1271 * native support for Proof General, both for classic Isabelle and
  1272 Isabelle/Isar;
  1273 
  1274 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1275 using the graph browser tool;
  1276 
  1277 * Isabelle manuals now also available as PDF;
  1278 
  1279 * theory loader rewritten from scratch (may not be fully
  1280 bug-compatible); old loadpath variable has been replaced by show_path,
  1281 add_path, del_path, reset_path functions; new operations such as
  1282 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1283 isatool doc ref);
  1284 
  1285 * improved isatool install: option -k creates KDE application icon,
  1286 option -p DIR installs standalone binaries;
  1287 
  1288 * added ML_PLATFORM setting (useful for cross-platform installations);
  1289 more robust handling of platform specific ML images for SML/NJ;
  1290 
  1291 * the settings environment is now statically scoped, i.e. it is never
  1292 created again in sub-processes invoked from isabelle, isatool, or
  1293 Isabelle;
  1294 
  1295 * path element specification '~~' refers to '$ISABELLE_HOME';
  1296 
  1297 * in locales, the "assumes" and "defines" parts may be omitted if
  1298 empty;
  1299 
  1300 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1301 long arrows);
  1302 
  1303 * new print_mode "HTML";
  1304 
  1305 * new flag show_tags controls display of tags of theorems (which are
  1306 basically just comments that may be attached by some tools);
  1307 
  1308 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1309 mode and goal output format:
  1310 
  1311 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1312 244c244
  1313 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1314 ---
  1315 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1316 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1317 181c181
  1318 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1319 ---
  1320 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1321 
  1322 * function bind_thms stores lists of theorems (cf. bind_thm);
  1323 
  1324 * new shorthand tactics ftac, eatac, datac, fatac;
  1325 
  1326 * qed (and friends) now accept "" as result name; in that case the
  1327 theorem is not stored, but proper checks and presentation of the
  1328 result still apply;
  1329 
  1330 * theorem database now also indexes constants "Trueprop", "all",
  1331 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1332 
  1333 
  1334 *** HOL ***
  1335 
  1336 ** HOL arithmetic **
  1337 
  1338 * There are now decision procedures for linear arithmetic over nat and
  1339 int:
  1340 
  1341 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1342 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1343 are treated as atomic; subformulae not involving type `nat' or `int'
  1344 are ignored; quantified subformulae are ignored unless they are
  1345 positive universal or negative existential. The tactic has to be
  1346 invoked by hand and can be a little bit slow. In particular, the
  1347 running time is exponential in the number of occurrences of `min' and
  1348 `max', and `-' on `nat'.
  1349 
  1350 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1351 (negated) (in)equalities among the premises and the conclusion into
  1352 account (i.e. no compound formulae) and does not know about `min' and
  1353 `max', and `-' on `nat'. It is fast and is used automatically by the
  1354 simplifier.
  1355 
  1356 NB: At the moment, these decision procedures do not cope with mixed
  1357 nat/int formulae where the two parts interact, such as `m < n ==>
  1358 int(m) < int(n)'.
  1359 
  1360 * HOL/Numeral provides a generic theory of numerals (encoded
  1361 efficiently as bit strings); setup for types nat/int/real is in place;
  1362 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1363 int, existing theories and proof scripts may require a few additional
  1364 type constraints;
  1365 
  1366 * integer division and remainder can now be performed on constant
  1367 arguments;
  1368 
  1369 * many properties of integer multiplication, division and remainder
  1370 are now available;
  1371 
  1372 * An interface to the Stanford Validity Checker (SVC) is available through the
  1373 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1374 are proved automatically.  SVC must be installed separately, and its results
  1375 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1376 invocation of the underlying oracle).  For SVC see
  1377   http://verify.stanford.edu/SVC
  1378 
  1379 * IsaMakefile: the HOL-Real target now builds an actual image;
  1380 
  1381 
  1382 ** HOL misc **
  1383 
  1384 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1385 (in Isabelle/Isar) -- by Gertrud Bauer;
  1386 
  1387 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1388 analysis for assembly languages with subtypes;
  1389 
  1390 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1391 -- avoids syntactic ambiguities and treats state, transition, and
  1392 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1393 changed syntax and (many) tactics;
  1394 
  1395 * HOL/inductive: Now also handles more general introduction rules such
  1396   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1397   theorems are now maintained within the theory (maintained via the
  1398   "mono" attribute);
  1399 
  1400 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1401   (using function types) such as
  1402 
  1403   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1404 
  1405 * HOL/record: record_simproc (part of the default simpset) takes care
  1406 of selectors applied to updated records; record_split_tac is no longer
  1407 part of the default claset; update_defs may now be removed from the
  1408 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1409 
  1410   claset_ref () := claset() addSWrapper record_split_wrapper;
  1411   Delsimprocs [record_simproc]
  1412 
  1413 * HOL/typedef: fixed type inference for representing set; type
  1414 arguments now have to occur explicitly on the rhs as type constraints;
  1415 
  1416 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1417 names rather than an ML expression;
  1418 
  1419 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1420 supplied later.  Program schemes can be defined, such as
  1421     "While B C s = (if B s then While B C (C s) else s)"
  1422 where the well-founded relation can be chosen after B and C have been given.
  1423 
  1424 * HOL/List: the constructors of type list are now Nil and Cons;
  1425 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1426 course, ML tools referring to List.list.op # etc. have to be adapted;
  1427 
  1428 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1429 disabled by default; run isabelle with option -m HOL to get back to
  1430 the original Gordon/HOL-style output;
  1431 
  1432 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1433 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1434 
  1435 * HOL basic syntax simplified (more orthogonal): all variants of
  1436 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1437 Eps operator is provided as well: "SOME x. P[x]";
  1438 
  1439 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1440 
  1441 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1442 thus available for user theories;
  1443 
  1444 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1445 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1446 time;
  1447 
  1448 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1449 several times and then mp;
  1450 
  1451 
  1452 *** LK ***
  1453 
  1454 * the notation <<...>> is now available as a notation for sequences of
  1455 formulas;
  1456 
  1457 * the simplifier is now installed
  1458 
  1459 * the axiom system has been generalized (thanks to Soren Heilmann)
  1460 
  1461 * the classical reasoner now has a default rule database
  1462 
  1463 
  1464 *** ZF ***
  1465 
  1466 * new primrec section allows primitive recursive functions to be given
  1467 directly (as in HOL) over datatypes and the natural numbers;
  1468 
  1469 * new tactics induct_tac and exhaust_tac for induction (or case
  1470 analysis) over datatypes and the natural numbers;
  1471 
  1472 * the datatype declaration of type T now defines the recursor T_rec;
  1473 
  1474 * simplification automatically does freeness reasoning for datatype
  1475 constructors;
  1476 
  1477 * automatic type-inference, with AddTCs command to insert new
  1478 type-checking rules;
  1479 
  1480 * datatype introduction rules are now added as Safe Introduction rules
  1481 to the claset;
  1482 
  1483 * the syntax "if P then x else y" is now available in addition to
  1484 if(P,x,y);
  1485 
  1486 
  1487 *** Internal programming interfaces ***
  1488 
  1489 * tuned simplifier trace output; new flag debug_simp;
  1490 
  1491 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1492 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1493 
  1494 * AxClass.axclass_tac lost the theory argument;
  1495 
  1496 * tuned current_goals_markers semantics: begin / end goal avoids
  1497 printing empty lines;
  1498 
  1499 * removed prs and prs_fn hook, which was broken because it did not
  1500 include \n in its semantics, forcing writeln to add one
  1501 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1502 string -> unit if you really want to output text without newline;
  1503 
  1504 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1505 plain output, interface builders may have to enable 'isabelle_font'
  1506 mode to get Isabelle font glyphs as before;
  1507 
  1508 * refined token_translation interface; INCOMPATIBILITY: output length
  1509 now of type real instead of int;
  1510 
  1511 * theory loader actions may be traced via new ThyInfo.add_hook
  1512 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1513 your own database of information attached to *whole* theories -- as
  1514 opposed to intra-theory data slots offered via TheoryDataFun;
  1515 
  1516 * proper handling of dangling sort hypotheses (at last!);
  1517 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1518 extra sort hypotheses that can be witnessed from the type signature;
  1519 the force_strip_shyps flag is gone, any remaining shyps are simply
  1520 left in the theorem (with a warning issued by strip_shyps_warning);
  1521 
  1522 
  1523 
  1524 New in Isabelle98-1 (October 1998)
  1525 ----------------------------------
  1526 
  1527 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1528 
  1529 * several changes of automated proof tools;
  1530 
  1531 * HOL: major changes to the inductive and datatype packages, including
  1532 some minor incompatibilities of theory syntax;
  1533 
  1534 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1535 called `inj_on';
  1536 
  1537 * HOL: removed duplicate thms in Arith:
  1538   less_imp_add_less  should be replaced by  trans_less_add1
  1539   le_imp_add_le      should be replaced by  trans_le_add1
  1540 
  1541 * HOL: unary minus is now overloaded (new type constraints may be
  1542 required);
  1543 
  1544 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1545 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1546 now taken as an integer constant.
  1547 
  1548 * Pure: ML function 'theory_of' renamed to 'theory';
  1549 
  1550 
  1551 *** Proof tools ***
  1552 
  1553 * Simplifier:
  1554   1. Asm_full_simp_tac is now more aggressive.
  1555      1. It will sometimes reorient premises if that increases their power to
  1556         simplify.
  1557      2. It does no longer proceed strictly from left to right but may also
  1558         rotate premises to achieve further simplification.
  1559      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1560      old Asm_full_simp_tac in that it does not rotate premises.
  1561   2. The simplifier now knows a little bit about nat-arithmetic.
  1562 
  1563 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1564 allows for selected deletion of wrappers, by introduction of names for
  1565 wrapper functionals.  This implies that addbefore, addSbefore,
  1566 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1567 and that adding two tactics with the same name overwrites the first
  1568 one (emitting a warning).
  1569   type wrapper = (int -> tactic) -> (int -> tactic)
  1570   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1571   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1572   delWrapper, delSWrapper: claset *  string            -> claset
  1573   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1574 
  1575 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1576 semantics; addbefore now affects only the unsafe part of step_tac
  1577 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1578 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1579 by Force_tac;
  1580 
  1581 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1582 compWrapper; added safe wrapper (and access functions for it);
  1583 
  1584 * HOL/split_all_tac is now much faster and fails if there is nothing
  1585 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1586 and the names of the automatically generated variables have changed.
  1587 split_all_tac has moved within claset() from unsafe wrappers to safe
  1588 wrappers, which means that !!-bound variables are split much more
  1589 aggressively, and safe_tac and clarify_tac now split such variables.
  1590 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1591 Note: the same holds for record_split_tac, which does the job of
  1592 split_all_tac for record fields.
  1593 
  1594 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1595 permanently to the default simpset using Addsplits just like
  1596 Addsimps. They can be removed via Delsplits just like
  1597 Delsimps. Lower-case versions are also available.
  1598 
  1599 * HOL/Simplifier: The rule split_if is now part of the default
  1600 simpset. This means that the simplifier will eliminate all occurrences
  1601 of if-then-else in the conclusion of a goal. To prevent this, you can
  1602 either remove split_if completely from the default simpset by
  1603 `Delsplits [split_if]' or remove it in a specific call of the
  1604 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1605 other case splitting rules to/from the default simpset: every datatype
  1606 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1607 t is the name of the datatype).
  1608 
  1609 * Classical reasoner / Simplifier combination: new force_tac (and
  1610 derivatives Force_tac, force) combines rewriting and classical
  1611 reasoning (and whatever other tools) similarly to auto_tac, but is
  1612 aimed to solve the given subgoal completely.
  1613 
  1614 
  1615 *** General ***
  1616 
  1617 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1618 and `goalw': the theory is no longer needed as an explicit argument -
  1619 the current theory context is used; assumptions are no longer returned
  1620 at the ML-level unless one of them starts with ==> or !!; it is
  1621 recommended to convert to these new commands using isatool fixgoal
  1622 (backup your sources first!);
  1623 
  1624 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1625 the current theory context, and 'theory' to lookup stored theories;
  1626 
  1627 * new theory section 'locale' for declaring constants, assumptions and
  1628 definitions that have local scope;
  1629 
  1630 * new theory section 'nonterminals' for purely syntactic types;
  1631 
  1632 * new theory section 'setup' for generic ML setup functions
  1633 (e.g. package initialization);
  1634 
  1635 * the distribution now includes Isabelle icons: see
  1636 lib/logo/isabelle-{small,tiny}.xpm;
  1637 
  1638 * isatool install - install binaries with absolute references to
  1639 ISABELLE_HOME/bin;
  1640 
  1641 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1642 
  1643 * print mode 'emacs' reserved for Isamode;
  1644 
  1645 * support multiple print (ast) translations per constant name;
  1646 
  1647 * theorems involving oracles are now printed with a suffixed [!];
  1648 
  1649 
  1650 *** HOL ***
  1651 
  1652 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1653 
  1654 * HOL/inductive package reorganized and improved: now supports mutual
  1655 definitions such as
  1656 
  1657   inductive EVEN ODD
  1658     intrs
  1659       null "0 : EVEN"
  1660       oddI "n : EVEN ==> Suc n : ODD"
  1661       evenI "n : ODD ==> Suc n : EVEN"
  1662 
  1663 new theorem list "elims" contains an elimination rule for each of the
  1664 recursive sets; inductive definitions now handle disjunctive premises
  1665 correctly (also ZF);
  1666 
  1667 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1668 "mutual_induct" no longer exists - the induction rule is always
  1669 contained in "induct";
  1670 
  1671 
  1672 * HOL/datatype package re-implemented and greatly improved: now
  1673 supports mutually recursive datatypes such as
  1674 
  1675   datatype
  1676     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1677             | SUM ('a aexp) ('a aexp)
  1678             | DIFF ('a aexp) ('a aexp)
  1679             | NUM 'a
  1680   and
  1681     'a bexp = LESS ('a aexp) ('a aexp)
  1682             | AND ('a bexp) ('a bexp)
  1683             | OR ('a bexp) ('a bexp)
  1684 
  1685 as well as indirectly recursive datatypes such as
  1686 
  1687   datatype
  1688     ('a, 'b) term = Var 'a
  1689                   | App 'b ((('a, 'b) term) list)
  1690 
  1691 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1692 induction on mutually / indirectly recursive datatypes.
  1693 
  1694 Primrec equations are now stored in theory and can be accessed via
  1695 <function_name>.simps.
  1696 
  1697 INCOMPATIBILITIES:
  1698 
  1699   - Theories using datatypes must now have theory Datatype as an
  1700     ancestor.
  1701   - The specific <typename>.induct_tac no longer exists - use the
  1702     generic induct_tac instead.
  1703   - natE has been renamed to nat.exhaust - use exhaust_tac
  1704     instead of res_inst_tac ... natE. Note that the variable
  1705     names in nat.exhaust differ from the names in natE, this
  1706     may cause some "fragile" proofs to fail.
  1707   - The theorems split_<typename>_case and split_<typename>_case_asm
  1708     have been renamed to <typename>.split and <typename>.split_asm.
  1709   - Since default sorts of type variables are now handled correctly,
  1710     some datatype definitions may have to be annotated with explicit
  1711     sort constraints.
  1712   - Primrec definitions no longer require function name and type
  1713     of recursive argument.
  1714 
  1715 Consider using isatool fixdatatype to adapt your theories and proof
  1716 scripts to the new package (backup your sources first!).
  1717 
  1718 
  1719 * HOL/record package: considerably improved implementation; now
  1720 includes concrete syntax for record types, terms, updates; theorems
  1721 for surjective pairing and splitting !!-bound record variables; proof
  1722 support is as follows:
  1723 
  1724   1) standard conversions (selectors or updates applied to record
  1725 constructor terms) are part of the standard simpset;
  1726 
  1727   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1728 made part of standard simpset and claset via addIffs;
  1729 
  1730   3) a tactic for record field splitting (record_split_tac) is part of
  1731 the standard claset (addSWrapper);
  1732 
  1733 To get a better idea about these rules you may retrieve them via
  1734 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1735 the name of your record type.
  1736 
  1737 The split tactic 3) conceptually simplifies by the following rule:
  1738 
  1739   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1740 
  1741 Thus any record variable that is bound by meta-all will automatically
  1742 blow up into some record constructor term, consequently the
  1743 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1744 solve record problems automatically.
  1745 
  1746 
  1747 * reorganized the main HOL image: HOL/Integ and String loaded by
  1748 default; theory Main includes everything;
  1749 
  1750 * automatic simplification of integer sums and comparisons, using cancellation;
  1751 
  1752 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1753 
  1754 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1755 
  1756 * many new identities for unions, intersections, set difference, etc.;
  1757 
  1758 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1759 called split_if, split_split, split_sum_case and split_nat_case (to go
  1760 with add/delsplits);
  1761 
  1762 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1763 (?x::unit) = (); this is made part of the default simpset, which COULD
  1764 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1765 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1766 unit_abs_eta_conv is added in order to counter the effect of
  1767 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1768 %u.f();
  1769 
  1770 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1771 makes more sense);
  1772 
  1773 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1774   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1775   disjointness reasoning but breaking a few old proofs.
  1776 
  1777 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1778 to 'converse' from 'inverse' (for compatibility with ZF and some
  1779 literature);
  1780 
  1781 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1782 the well-founded relation;
  1783 
  1784 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1785     Compl A.  The "Compl" syntax remains available as input syntax for this
  1786     release ONLY.
  1787 
  1788 * HOL/Update: new theory of function updates:
  1789     f(a:=b) == %x. if x=a then b else f x
  1790 may also be iterated as in f(a:=b,c:=d,...);
  1791 
  1792 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1793 
  1794 * HOL/List:
  1795   - new function list_update written xs[i:=v] that updates the i-th
  1796     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1797   - new function `upt' written [i..j(] which generates the list
  1798     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1799     bound write [i..j], which is a shorthand for [i..j+1(].
  1800   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1801 
  1802 * HOL/Arith:
  1803   - removed 'pred' (predecessor) function;
  1804   - generalized some theorems about n-1;
  1805   - many new laws about "div" and "mod";
  1806   - new laws about greatest common divisors (see theory ex/Primes);
  1807 
  1808 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1809 instead of "inverse";
  1810 
  1811 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1812   of the multiset ordering;
  1813 
  1814 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1815   (not included by default);
  1816 
  1817 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1818 
  1819 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1820   programs, i.e. different program variables may have different types.
  1821 
  1822 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1823   [previously, this check worked only if the rewrite rule was unconditional]
  1824   Now rew can involve either definitions or equalities (either == or =).
  1825 
  1826 
  1827 *** ZF ***
  1828 
  1829 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1830   only the theorems proved on ZF.ML;
  1831 
  1832 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1833   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1834   disjointness reasoning but breaking a few old proofs.
  1835 
  1836 * ZF/Update: new theory of function updates
  1837     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1838   may also be iterated as in f(a:=b,c:=d,...);
  1839 
  1840 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1841 
  1842 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1843   [previously, this check worked only if the rewrite rule was unconditional]
  1844   Now rew can involve either definitions or equalities (either == or =).
  1845 
  1846 * case_tac provided for compatibility with HOL
  1847     (like the old excluded_middle_tac, but with subgoals swapped)
  1848 
  1849 
  1850 *** Internal programming interfaces ***
  1851 
  1852 * Pure: several new basic modules made available for general use, see
  1853 also src/Pure/README;
  1854 
  1855 * improved the theory data mechanism to support encapsulation (data
  1856 kind name replaced by private Object.kind, acting as authorization
  1857 key); new type-safe user interface via functor TheoryDataFun; generic
  1858 print_data function becomes basically useless;
  1859 
  1860 * removed global_names compatibility flag -- all theory declarations
  1861 are qualified by default;
  1862 
  1863 * module Pure/Syntax now offers quote / antiquote translation
  1864 functions (useful for Hoare logic etc. with implicit dependencies);
  1865 see HOL/ex/Antiquote for an example use;
  1866 
  1867 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1868 cterm -> thm;
  1869 
  1870 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1871 subgoal;
  1872 
  1873 * Display.print_goals function moved to Locale.print_goals;
  1874 
  1875 * standard print function for goals supports current_goals_markers
  1876 variable for marking begin of proof, end of proof, start of goal; the
  1877 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1878 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1879 for example;
  1880 
  1881 
  1882 
  1883 New in Isabelle98 (January 1998)
  1884 --------------------------------
  1885 
  1886 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1887 
  1888 * changed lexical syntax of terms / types: dots made part of long
  1889 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1890 
  1891 * simpset (and claset) reference variable replaced by functions
  1892 simpset / simpset_ref;
  1893 
  1894 * no longer supports theory aliases (via merge) and non-trivial
  1895 implicit merge of thms' signatures;
  1896 
  1897 * most internal names of constants changed due to qualified names;
  1898 
  1899 * changed Pure/Sequence interface (see Pure/seq.ML);
  1900 
  1901 
  1902 *** General Changes ***
  1903 
  1904 * hierachically structured name spaces (for consts, types, axms, thms
  1905 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1906 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1907 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1908 long_names for fully qualified output names; NOTE: ML programs
  1909 (special tactics, packages etc.) referring to internal names may have
  1910 to be adapted to cope with fully qualified names; in case of severe
  1911 backward campatibility problems try setting 'global_names' at compile
  1912 time to have enrything declared within a flat name space; one may also
  1913 fine tune name declarations in theories via the 'global' and 'local'
  1914 section;
  1915 
  1916 * reimplemented the implicit simpset and claset using the new anytype
  1917 data filed in signatures; references simpset:simpset ref etc. are
  1918 replaced by functions simpset:unit->simpset and
  1919 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1920 to patch your ML files accordingly;
  1921 
  1922 * HTML output now includes theory graph data for display with Java
  1923 applet or isatool browser; data generated automatically via isatool
  1924 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1925 
  1926 * defs may now be conditional; improved rewrite_goals_tac to handle
  1927 conditional equations;
  1928 
  1929 * defs now admits additional type arguments, using TYPE('a) syntax;
  1930 
  1931 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1932 creates a new theory node; implicit merge of thms' signatures is
  1933 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1934 transfer:theory->thm->thm in (rare) cases;
  1935 
  1936 * improved handling of draft signatures / theories; draft thms (and
  1937 ctyps, cterms) are automatically promoted to real ones;
  1938 
  1939 * slightly changed interfaces for oracles: admit many per theory, named
  1940 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1941 
  1942 * print_goals: optional output of const types (set show_consts and
  1943 show_types);
  1944 
  1945 * improved output of warnings (###) and errors (***);
  1946 
  1947 * subgoal_tac displays a warning if the new subgoal has type variables;
  1948 
  1949 * removed old README and Makefiles;
  1950 
  1951 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1952 
  1953 * removed obsolete init_pps and init_database;
  1954 
  1955 * deleted the obsolete tactical STATE, which was declared by
  1956     fun STATE tacfun st = tacfun st st;
  1957 
  1958 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1959 (which abbreviates $HOME);
  1960 
  1961 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1962 use isatool fixseq to adapt your ML programs (this works for fully
  1963 qualified references to the Sequence structure only!);
  1964 
  1965 * use_thy no longer requires writable current directory; it always
  1966 reloads .ML *and* .thy file, if either one is out of date;
  1967 
  1968 
  1969 *** Classical Reasoner ***
  1970 
  1971 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1972 tactics that use classical reasoning to simplify a subgoal without
  1973 splitting it into several subgoals;
  1974 
  1975 * Safe_tac: like safe_tac but uses the default claset;
  1976 
  1977 
  1978 *** Simplifier ***
  1979 
  1980 * added simplification meta rules:
  1981     (asm_)(full_)simplify: simpset -> thm -> thm;
  1982 
  1983 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1984 logics (again);
  1985 
  1986 * added prems argument to simplification procedures;
  1987 
  1988 * HOL, FOL, ZF: added infix function `addsplits':
  1989   instead of `<simpset> setloop (split_tac <thms>)'
  1990   you can simply write `<simpset> addsplits <thms>'
  1991 
  1992 
  1993 *** Syntax ***
  1994 
  1995 * TYPE('a) syntax for type reflection terms;
  1996 
  1997 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1998 
  1999 * pretty printer: changed order of mixfix annotation preference (again!);
  2000 
  2001 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2002 
  2003 
  2004 *** HOL ***
  2005 
  2006 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2007   with `addloop' of the simplifier to faciliate case splitting in premises.
  2008 
  2009 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2010 
  2011 * HOL/Auth: new protocol proofs including some for the Internet
  2012   protocol TLS;
  2013 
  2014 * HOL/Map: new theory of `maps' a la VDM;
  2015 
  2016 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2017 cancelling out common nat summands from =, <, <= (in)equalities, or
  2018 differences; simplification procedures nat_cancel_factor for
  2019 cancelling common factor from =, <, <= (in)equalities over natural
  2020 sums; nat_cancel contains both kinds of procedures, it is installed by
  2021 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2022 
  2023 * HOL/simplifier: terms of the form
  2024   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2025   are rewritten to
  2026   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2027   and those of the form
  2028   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2029   are rewritten to
  2030   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2031 
  2032 * HOL/datatype
  2033   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2034 
  2035   P(t_case f1 ... fn x) =
  2036      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2037         ...
  2038        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2039      )
  2040 
  2041   and a theorem `split_t_case_asm' of the form
  2042 
  2043   P(t_case f1 ... fn x) =
  2044     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2045         ...
  2046        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2047      )
  2048   which can be added to a simpset via `addsplits'. The existing theorems
  2049   expand_list_case and expand_option_case have been renamed to
  2050   split_list_case and split_option_case.
  2051 
  2052 * HOL/Arithmetic:
  2053   - `pred n' is automatically converted to `n-1'.
  2054     Users are strongly encouraged not to use `pred' any longer,
  2055     because it will disappear altogether at some point.
  2056   - Users are strongly encouraged to write "0 < n" rather than
  2057     "n ~= 0". Theorems and proof tools have been modified towards this
  2058     `standard'.
  2059 
  2060 * HOL/Lists:
  2061   the function "set_of_list" has been renamed "set" (and its theorems too);
  2062   the function "nth" now takes its arguments in the reverse order and
  2063   has acquired the infix notation "!" as in "xs!n".
  2064 
  2065 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2066 
  2067 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2068   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2069 
  2070 * HOL/record: extensible records with schematic structural subtyping
  2071 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2072 still lacks various theorems and concrete record syntax;
  2073 
  2074 
  2075 *** HOLCF ***
  2076 
  2077 * removed "axioms" and "generated by" sections;
  2078 
  2079 * replaced "ops" section by extended "consts" section, which is capable of
  2080   handling the continuous function space "->" directly;
  2081 
  2082 * domain package:
  2083   . proves theorems immediately and stores them in the theory,
  2084   . creates hierachical name space,
  2085   . now uses normal mixfix annotations (instead of cinfix...),
  2086   . minor changes to some names and values (for consistency),
  2087   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2088   . separator between mutual domain defs: changed "," to "and",
  2089   . improved handling of sort constraints;  now they have to
  2090     appear on the left-hand side of the equations only;
  2091 
  2092 * fixed LAM <x,y,zs>.b syntax;
  2093 
  2094 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2095 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2096 
  2097 
  2098 *** FOL and ZF ***
  2099 
  2100 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2101   with `addloop' of the simplifier to faciliate case splitting in premises.
  2102 
  2103 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2104 in HOL, they strip ALL and --> from proved theorems;
  2105 
  2106 
  2107 
  2108 New in Isabelle94-8 (May 1997)
  2109 ------------------------------
  2110 
  2111 *** General Changes ***
  2112 
  2113 * new utilities to build / run / maintain Isabelle etc. (in parts
  2114 still somewhat experimental); old Makefiles etc. still functional;
  2115 
  2116 * new 'Isabelle System Manual';
  2117 
  2118 * INSTALL text, together with ./configure and ./build scripts;
  2119 
  2120 * reimplemented type inference for greater efficiency, better error
  2121 messages and clean internal interface;
  2122 
  2123 * prlim command for dealing with lots of subgoals (an easier way of
  2124 setting goals_limit);
  2125 
  2126 
  2127 *** Syntax ***
  2128 
  2129 * supports alternative (named) syntax tables (parser and pretty
  2130 printer); internal interface is provided by add_modesyntax(_i);
  2131 
  2132 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2133 be used in conjunction with the Isabelle symbol font; uses the
  2134 "symbols" syntax table;
  2135 
  2136 * added token_translation interface (may translate name tokens in
  2137 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2138 the current print_mode); IMPORTANT: user print translation functions
  2139 are responsible for marking newly introduced bounds
  2140 (Syntax.mark_boundT);
  2141 
  2142 * token translations for modes "xterm" and "xterm_color" that display
  2143 names in bold, underline etc. or colors (which requires a color
  2144 version of xterm);
  2145 
  2146 * infixes may now be declared with names independent of their syntax;
  2147 
  2148 * added typed_print_translation (like print_translation, but may
  2149 access type of constant);
  2150 
  2151 
  2152 *** Classical Reasoner ***
  2153 
  2154 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2155 some limitations.  Blast_tac...
  2156   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2157   + ignores elimination rules that don't have the correct format
  2158         (the conclusion MUST be a formula variable)
  2159   + ignores types, which can make HOL proofs fail
  2160   + rules must not require higher-order unification, e.g. apply_type in ZF
  2161     [message "Function Var's argument not a bound variable" relates to this]
  2162   + its proof strategy is more general but can actually be slower
  2163 
  2164 * substitution with equality assumptions no longer permutes other
  2165 assumptions;
  2166 
  2167 * minor changes in semantics of addafter (now called addaltern); renamed
  2168 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2169 (and access functions for it);
  2170 
  2171 * improved combination of classical reasoner and simplifier:
  2172   + functions for handling clasimpsets
  2173   + improvement of addss: now the simplifier is called _after_ the
  2174     safe steps.
  2175   + safe variant of addss called addSss: uses safe simplifications
  2176     _during_ the safe steps. It is more complete as it allows multiple
  2177     instantiations of unknowns (e.g. with slow_tac).
  2178 
  2179 *** Simplifier ***
  2180 
  2181 * added interface for simplification procedures (functions that
  2182 produce *proven* rewrite rules on the fly, depending on current
  2183 redex);
  2184 
  2185 * ordering on terms as parameter (used for ordered rewriting);
  2186 
  2187 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2188 
  2189 * the solver is now split into a safe and an unsafe part.
  2190 This should be invisible for the normal user, except that the
  2191 functions setsolver and addsolver have been renamed to setSolver and
  2192 addSolver; added safe_asm_full_simp_tac;
  2193 
  2194 
  2195 *** HOL ***
  2196 
  2197 * a generic induction tactic `induct_tac' which works for all datatypes and
  2198 also for type `nat';
  2199 
  2200 * a generic case distinction tactic `exhaust_tac' which works for all
  2201 datatypes and also for type `nat';
  2202 
  2203 * each datatype comes with a function `size';
  2204 
  2205 * patterns in case expressions allow tuple patterns as arguments to
  2206 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2207 
  2208 * primrec now also works with type nat;
  2209 
  2210 * recdef: a new declaration form, allows general recursive functions to be
  2211 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2212 
  2213 * the constant for negation has been renamed from "not" to "Not" to
  2214 harmonize with FOL, ZF, LK, etc.;
  2215 
  2216 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2217 infinite lists;
  2218 
  2219 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2220 
  2221 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2222 problems in commutative rings, using axiomatic type classes for + and *;
  2223 
  2224 * more examples in HOL/MiniML and HOL/Auth;
  2225 
  2226 * more default rewrite rules for quantifiers, union/intersection;
  2227 
  2228 * a new constant `arbitrary == @x.False';
  2229 
  2230 * HOLCF/IOA replaces old HOL/IOA;
  2231 
  2232 * HOLCF changes: derived all rules and arities
  2233   + axiomatic type classes instead of classes
  2234   + typedef instead of faking type definitions
  2235   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2236   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2237   + eliminated the types void, one, tr
  2238   + use unit lift and bool lift (with translations) instead of one and tr
  2239   + eliminated blift from Lift3.thy (use Def instead of blift)
  2240   all eliminated rules are derived as theorems --> no visible changes ;
  2241 
  2242 
  2243 *** ZF ***
  2244 
  2245 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2246 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2247 as ZF_cs addSIs [equalityI];
  2248 
  2249 
  2250 
  2251 New in Isabelle94-7 (November 96)
  2252 ---------------------------------
  2253 
  2254 * allowing negative levels (as offsets) in prlev and choplev;
  2255 
  2256 * super-linear speedup for large simplifications;
  2257 
  2258 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2259 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2260 FAIL); can suppress it using the command Delsimps (ex_simps @
  2261 all_simps); De Morgan laws are also now included, by default;
  2262 
  2263 * improved printing of ==>  :  ~:
  2264 
  2265 * new object-logic "Sequents" adds linear logic, while replacing LK
  2266 and Modal (thanks to Sara Kalvala);
  2267 
  2268 * HOL/Auth: correctness proofs for authentication protocols;
  2269 
  2270 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2271 examples on HOL/Auth);
  2272 
  2273 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2274 the rewriter and classical reasoner simultaneously;
  2275 
  2276 * function uresult no longer returns theorems in "standard" format;
  2277 regain previous version by: val uresult = standard o uresult;
  2278 
  2279 
  2280 
  2281 New in Isabelle94-6
  2282 -------------------
  2283 
  2284 * oracles -- these establish an interface between Isabelle and trusted
  2285 external reasoners, which may deliver results as theorems;
  2286 
  2287 * proof objects (in particular record all uses of oracles);
  2288 
  2289 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2290 
  2291 * "constdefs" section in theory files;
  2292 
  2293 * "primrec" section (HOL) no longer requires names;
  2294 
  2295 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2296 
  2297 
  2298 
  2299 New in Isabelle94-5
  2300 -------------------
  2301 
  2302 * reduced space requirements;
  2303 
  2304 * automatic HTML generation from theories;
  2305 
  2306 * theory files no longer require "..." (quotes) around most types;
  2307 
  2308 * new examples, including two proofs of the Church-Rosser theorem;
  2309 
  2310 * non-curried (1994) version of HOL is no longer distributed;
  2311 
  2312 
  2313 
  2314 New in Isabelle94-4
  2315 -------------------
  2316 
  2317 * greatly reduced space requirements;
  2318 
  2319 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2320 
  2321 * searchable theorem database (see the section "Retrieving theorems" on
  2322 page 8 of the Reference Manual);
  2323 
  2324 * new examples, including Grabczewski's monumental case study of the
  2325 Axiom of Choice;
  2326 
  2327 * The previous version of HOL renamed to Old_HOL;
  2328 
  2329 * The new version of HOL (previously called CHOL) uses a curried syntax
  2330 for functions.  Application looks like f a b instead of f(a,b);
  2331 
  2332 * Mutually recursive inductive definitions finally work in HOL;
  2333 
  2334 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2335 translates to the operator "split";
  2336 
  2337 
  2338 
  2339 New in Isabelle94-3
  2340 -------------------
  2341 
  2342 * new infix operator, addss, allowing the classical reasoner to
  2343 perform simplification at each step of its search.  Example:
  2344         fast_tac (cs addss ss)
  2345 
  2346 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2347 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2348 look like (a,b) instead of <a,b>;
  2349 
  2350 * PLEASE NOTE: CHOL will eventually replace HOL!
  2351 
  2352 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2353 It translates to the operator "split".  A new theory of integers is available;
  2354 
  2355 * In ZF, integer numerals now denote two's-complement binary integers.
  2356 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2357 
  2358 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2359 of the Axiom of Choice;
  2360 
  2361 
  2362 
  2363 New in Isabelle94-2
  2364 -------------------
  2365 
  2366 * Significantly faster resolution;
  2367 
  2368 * the different sections in a .thy file can now be mixed and repeated
  2369 freely;
  2370 
  2371 * Database of theorems for FOL, HOL and ZF.  New
  2372 commands including qed, qed_goal and bind_thm store theorems in the database.
  2373 
  2374 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2375 a given theory (thms_of), or find out what theory a theorem was proved in
  2376 (theory_of_thm);
  2377 
  2378 * Bugs fixed in the inductive definition and datatype packages;
  2379 
  2380 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2381 and HOL_dup_cs obsolete;
  2382 
  2383 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2384 have been removed;
  2385 
  2386 * Simpler definition of function space in ZF;
  2387 
  2388 * new results about cardinal and ordinal arithmetic in ZF;
  2389 
  2390 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2391 types;
  2392 
  2393 
  2394 $Id$