NEWS
author nipkow
Tue Mar 18 17:54:27 2003 +0100 (2003-03-18)
changeset 13868 01b516b64233
parent 13835 12b2ffbe543a
child 13872 601514e63534
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/simplifier:
    10 
    11   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    12     Assumptions are now subject to complete mutual simplification,
    13     not just from left to right. The simplifier now preserves
    14     the order of assumptions.
    15 
    16     Potential INCOMPATIBILITY:
    17 
    18     -- simp sometimes diverges where the old version did
    19        not, e.g. invoking simp on the goal
    20 
    21         [| P (f x); y = x; f x = f y |] ==> Q
    22 
    23        now gives rise to the infinite reduction sequence
    24 
    25         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    26 
    27        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    28        kind of problem.
    29 
    30     -- Tactics combining classical reasoner and simplification (such as auto)
    31        are also affected by this change, because many of them rely on
    32        simp. They may sometimes diverge as well or yield a different numbers
    33        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    34        in case of problems. Sometimes subsequent calls to the classical
    35        reasoner will fail because a preceeding call to the simplifier too
    36        eagerly simplified the goal, e.g. deleted redundant premises.
    37 
    38   - The simplifier trace now shows the names of the applied rewrite rules
    39 
    40   - 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 * Pure: The main goal of the proof state is no longer shown by default, only
    50 the subgoals. This behaviour is controlled by a new flag.
    51    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
    52 (ML: Proof.show_main_goal).
    53 
    54 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
    55 rules whose conclusion matches subgoal 1:
    56       PG menu: Isabelle/Isar -> Show me -> matching rules
    57 The rules are ordered by how closely they match the subgoal.
    58 In particular, rules that solve a subgoal outright are displayed first
    59 (or rather last, the way they are printed).
    60 (ML: ProofGeneral.print_intros())
    61 
    62 * Pure: New flag trace_unify_fail causes unification to print
    63 diagnostic information (PG: in trace buffer) when it fails. This is
    64 useful for figuring out why single step proofs like rule, erule or
    65 assumption failed.
    66 
    67 * Pure: Locale specifications now produce predicate definitions
    68 according to the body of text (covering assumptions modulo local
    69 definitions); predicate "loc_axioms" covers newly introduced text,
    70 while "loc" is cumulative wrt. all included locale expressions; the
    71 latter view is presented only on export into the global theory
    72 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    73 on the old view without predicates;
    74 
    75 * Pure: predefined locales "var" and "struct" are useful for sharing
    76 parameters (as in CASL, for example); just specify something like
    77 ``var x + var y + struct M'' as import;
    78 
    79 * Pure: improved thms_containing: proper indexing of facts instead of
    80 raw theorems; check validity of results wrt. current name space;
    81 include local facts of proof configuration (also covers active
    82 locales), cover fixed variables in index; may use "_" in term
    83 specification; an optional limit for the number of printed facts may
    84 be given (the default is 40);
    85 
    86 * Pure: disallow duplicate fact bindings within new-style theory files
    87 (batch-mode only);
    88 
    89 * Provers: improved induct method: assumptions introduced by case
    90 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    91 the goal statement); "foo" still refers to all facts collectively;
    92 
    93 * Provers: the function blast.overloaded has been removed: all constants
    94 are regarded as potentially overloaded, which improves robustness in exchange
    95 for slight decrease in efficiency;
    96 
    97 * Provers/linorder: New generic prover for transitivity reasoning over
    98 linear orders.  Note: this prover is not efficient!
    99 
   100 * Isar: preview of problems to finish 'show' now produce an error
   101 rather than just a warning (in interactive mode);
   102 
   103 
   104 *** HOL ***
   105 
   106 * GroupTheory: new, experimental summation operator for abelian groups.
   107 
   108 * New tactic "trans_tac" and method "trans" instantiate
   109 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   110 "<=", "<" and "="). 
   111 
   112 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   113 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   114 
   115 * 'typedef' command has new option "open" to suppress the set
   116 definition;
   117 
   118 * functions Min and Max on finite sets have been introduced (theory
   119 Finite_Set);
   120 
   121 * attribute [symmetric] now works for relations as well; it turns
   122 (x,y) : R^-1 into (y,x) : R, and vice versa;
   123 
   124 * arith(_tac) now produces a counter example if it cannot prove a theorem.
   125   In ProofGeneral the counter example appears in the trace buffer.
   126 
   127 * arith(_tac) does now know about div k and mod k where k is a numeral
   128 of type nat or int. It can solve simple goals like
   129 
   130   "0 < n ==> n div 2 < (n::nat)"
   131 
   132 but fails if divisibility plays a role like in
   133 
   134   "n div 2 + (n+1) div 2 = (n::nat)"
   135 
   136 * simp's arithmetic capabilities have been enhanced a bit: it now
   137 takes ~= in premises into account (by performing a case split);
   138 
   139 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   140 are distributed over a sum of terms;
   141 
   142 * induct over a !!-quantified statement (say !!x1..xn):
   143   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   144 
   145 * GroupTheory: converted to Isar theories, using locales with implicit structures;
   146 
   147 * Real/HahnBanach: updated and adapted to locales;
   148 
   149 
   150 *** ZF ***
   151 
   152 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   153 universe, etc.);
   154 
   155 * Main ZF: many theories converted to new-style format;
   156 
   157 
   158 *** ML ***
   159 
   160 * Pure: Tactic.prove provides sane interface for internal proofs;
   161 omits the infamous "standard" operation, so this is more appropriate
   162 than prove_goalw_cterm in many situations (e.g. in simprocs);
   163 
   164 * Pure: improved error reporting of simprocs;
   165 
   166 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   167 up simprocs;
   168 
   169 
   170 
   171 New in Isabelle2002 (March 2002)
   172 --------------------------------
   173 
   174 *** Document preparation ***
   175 
   176 * greatly simplified document preparation setup, including more
   177 graceful interpretation of isatool usedir -i/-d/-D options, and more
   178 instructive isatool mkdir; users should basically be able to get
   179 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   180 users may run a separate document processing stage manually like this:
   181 "isatool usedir -D output HOL Test && isatool document Test/output";
   182 
   183 * theory dependency graph may now be incorporated into documents;
   184 isatool usedir -g true will produce session_graph.eps/.pdf for use
   185 with \includegraphics of LaTeX;
   186 
   187 * proper spacing of consecutive markup elements, especially text
   188 blocks after section headings;
   189 
   190 * support bold style (for single symbols only), input syntax is like
   191 this: "\<^bold>\<alpha>" or "\<^bold>A";
   192 
   193 * \<bullet> is now output as bold \cdot by default, which looks much
   194 better in printed text;
   195 
   196 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   197 note that these symbols are currently unavailable in Proof General /
   198 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   199 
   200 * isatool latex no longer depends on changed TEXINPUTS, instead
   201 isatool document copies the Isabelle style files to the target
   202 location;
   203 
   204 
   205 *** Isar ***
   206 
   207 * Pure/Provers: improved proof by cases and induction;
   208   - 'case' command admits impromptu naming of parameters (such as
   209     "case (Suc n)");
   210   - 'induct' method divinates rule instantiation from the inductive
   211     claim; no longer requires excessive ?P bindings for proper
   212     instantiation of cases;
   213   - 'induct' method properly enumerates all possibilities of set/type
   214     rules; as a consequence facts may be also passed through *type*
   215     rules without further ado;
   216   - 'induct' method now derives symbolic cases from the *rulified*
   217     rule (before it used to rulify cases stemming from the internal
   218     atomized version); this means that the context of a non-atomic
   219     statement becomes is included in the hypothesis, avoiding the
   220     slightly cumbersome show "PROP ?case" form;
   221   - 'induct' may now use elim-style induction rules without chaining
   222     facts, using ``missing'' premises from the goal state; this allows
   223     rules stemming from inductive sets to be applied in unstructured
   224     scripts, while still benefitting from proper handling of non-atomic
   225     statements; NB: major inductive premises need to be put first, all
   226     the rest of the goal is passed through the induction;
   227   - 'induct' proper support for mutual induction involving non-atomic
   228     rule statements (uses the new concept of simultaneous goals, see
   229     below);
   230   - append all possible rule selections, but only use the first
   231     success (no backtracking);
   232   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   233   - undeclared rule case names default to numbers 1, 2, 3, ...;
   234   - added 'print_induct_rules' (covered by help item in recent Proof
   235     General versions);
   236   - moved induct/cases attributes to Pure, methods to Provers;
   237   - generic method setup instantiated for FOL and HOL;
   238 
   239 * Pure: support multiple simultaneous goal statements, for example
   240 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   241 meta-level mechanism, this acts as if several individual goals had
   242 been stated separately; in particular common proof methods need to be
   243 repeated in order to cover all claims; note that a single elimination
   244 step is *not* sufficient to establish the two conjunctions, so this
   245 fails:
   246 
   247   assume "A & B" then have A and B ..   (*".." fails*)
   248 
   249 better use "obtain" in situations as above; alternative refer to
   250 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   251 
   252 * Pure: proper integration with ``locales''; unlike the original
   253 version by Florian Kammüller, Isar locales package high-level proof
   254 contexts rather than raw logical ones (e.g. we admit to include
   255 attributes everywhere); operations on locales include merge and
   256 rename; support for implicit arguments (``structures''); simultaneous
   257 type-inference over imports and text; see also HOL/ex/Locales.thy for
   258 some examples;
   259 
   260 * Pure: the following commands have been ``localized'', supporting a
   261 target locale specification "(in name)": 'lemma', 'theorem',
   262 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   263 stored both within the locale and at the theory level (exported and
   264 qualified by the locale name);
   265 
   266 * Pure: theory goals may now be specified in ``long'' form, with
   267 ad-hoc contexts consisting of arbitrary locale elements. for example
   268 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   269 definitions may be given, too); the result is a meta-level rule with
   270 the context elements being discharged in the obvious way;
   271 
   272 * Pure: new proof command 'using' allows to augment currently used
   273 facts after a goal statement ('using' is syntactically analogous to
   274 'apply', but acts on the goal's facts only); this allows chained facts
   275 to be separated into parts given before and after a claim, as in
   276 ``from a and b have C using d and e <proof>'';
   277 
   278 * Pure: renamed "antecedent" case to "rule_context";
   279 
   280 * Pure: new 'judgment' command records explicit information about the
   281 object-logic embedding (used by several tools internally); no longer
   282 use hard-wired "Trueprop";
   283 
   284 * Pure: added 'corollary' command;
   285 
   286 * Pure: fixed 'token_translation' command;
   287 
   288 * Pure: removed obsolete 'exported' attribute;
   289 
   290 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   291 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   292 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   293 
   294 * Pure: method 'atomize' presents local goal premises as object-level
   295 statements (atomic meta-level propositions); setup controlled via
   296 rewrite rules declarations of 'atomize' attribute; example
   297 application: 'induct' method with proper rule statements in improper
   298 proof *scripts*;
   299 
   300 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   301 now consider the syntactic context of assumptions, giving a better
   302 chance to get type-inference of the arguments right (this is
   303 especially important for locales);
   304 
   305 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   306 mode;
   307 
   308 * Pure/obtain: the formal conclusion "thesis", being marked as
   309 ``internal'', may no longer be reference directly in the text;
   310 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   311 situations;
   312 
   313 * Pure: generic 'sym' attribute which declares a rule both as pure
   314 'elim?' and for the 'symmetric' operation;
   315 
   316 * Pure: marginal comments ``--'' may now occur just anywhere in the
   317 text; the fixed correlation with particular command syntax has been
   318 discontinued;
   319 
   320 * Pure: new method 'rules' is particularly well-suited for proof
   321 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   322 but often produces more compact proof terms with less detours;
   323 
   324 * Pure/Provers/classical: simplified integration with pure rule
   325 attributes and methods; the classical "intro?/elim?/dest?"
   326 declarations coincide with the pure ones; the "rule" method no longer
   327 includes classically swapped intros; "intro" and "elim" methods no
   328 longer pick rules from the context; also got rid of ML declarations
   329 AddXIs/AddXEs/AddXDs; all of this has some potential for
   330 INCOMPATIBILITY;
   331 
   332 * Provers/classical: attribute 'swapped' produces classical inversions
   333 of introduction rules;
   334 
   335 * Provers/simplifier: 'simplified' attribute may refer to explicit
   336 rules instead of full simplifier context; 'iff' attribute handles
   337 conditional rules;
   338 
   339 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   340 
   341 * HOL: 'recdef' now fails on unfinished automated proofs, use
   342 "(permissive)" option to recover old behavior;
   343 
   344 * HOL: 'inductive' no longer features separate (collective) attributes
   345 for 'intros' (was found too confusing);
   346 
   347 * HOL: properly declared induction rules less_induct and
   348 wf_induct_rule;
   349 
   350 
   351 *** HOL ***
   352 
   353 * HOL: moved over to sane numeral syntax; the new policy is as
   354 follows:
   355 
   356   - 0 and 1 are polymorphic constants, which are defined on any
   357   numeric type (nat, int, real etc.);
   358 
   359   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   360   binary representation internally;
   361 
   362   - type nat has special constructor Suc, and generally prefers Suc 0
   363   over 1::nat and Suc (Suc 0) over 2::nat;
   364 
   365 This change may cause significant problems of INCOMPATIBILITY; here
   366 are some hints on converting existing sources:
   367 
   368   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   369   entities, so expressions involving "-" (unary or binary minus) need
   370   to be spaced properly;
   371 
   372   - existing occurrences of "1" may need to be constraint "1::nat" or
   373   even replaced by Suc 0; similar for old "2";
   374 
   375   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   376 
   377   - remove all special provisions on numerals in proofs;
   378 
   379 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   380 representation (depends on bin_arith_simps in the default context);
   381 
   382 * HOL: symbolic syntax for x^2 (numeral 2);
   383 
   384 * HOL: the class of all HOL types is now called "type" rather than
   385 "term"; INCOMPATIBILITY, need to adapt references to this type class
   386 in axclass/classes, instance/arities, and (usually rare) occurrences
   387 in typings (of consts etc.); internally the class is called
   388 "HOL.type", ML programs should refer to HOLogic.typeS;
   389 
   390 * HOL/record package improvements:
   391   - new derived operations "fields" to build a partial record section,
   392     "extend" to promote a fixed record to a record scheme, and
   393     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   394     declared as simp by default;
   395   - shared operations ("more", "fields", etc.) now need to be always
   396     qualified) --- potential INCOMPATIBILITY;
   397   - removed "make_scheme" operations (use "make" with "extend") --
   398     INCOMPATIBILITY;
   399   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   400   - provides cases/induct rules for use with corresponding Isar
   401     methods (for concrete records, record schemes, concrete more
   402     parts, and schematic more parts -- in that order);
   403   - internal definitions directly based on a light-weight abstract
   404     theory of product types over typedef rather than datatype;
   405 
   406 * HOL: generic code generator for generating executable ML code from
   407 specifications; specific support for HOL constructs such as inductive
   408 datatypes and sets, as well as recursive functions; can be invoked
   409 via 'generate_code' theory section;
   410 
   411 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   412 
   413 * HOL: consolidated and renamed several theories.  In particular:
   414 	Ord.thy has been absorbed into HOL.thy
   415 	String.thy has been absorbed into List.thy
   416  
   417 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   418 (beware of argument permutation!);
   419 
   420 * HOL: linorder_less_split superseded by linorder_cases;
   421 
   422 * HOL/List: "nodups" renamed to "distinct";
   423 
   424 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   425 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   426   - Ex_def has changed, now need to use some_eq_ex
   427 
   428 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   429 in this (rare) case use:
   430 
   431   delSWrapper "split_all_tac"
   432   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   433 
   434 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   435 MAY FAIL;
   436 
   437 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   438 Isabelle's type classes, ^ on functions and relations has too general
   439 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   440 necessary to attach explicit type constraints;
   441 
   442 * HOL/Relation: the prefix name of the infix "O" has been changed from
   443 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   444 renamed accordingly (eg "compI" -> "rel_compI").
   445 
   446 * HOL: syntax translations now work properly with numerals and records
   447 expressions;
   448 
   449 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   450 of "lam" -- INCOMPATIBILITY;
   451 
   452 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   453 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   454 renamed "Product_Type.unit";
   455 
   456 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   457 
   458 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   459 the "cases" method);
   460 
   461 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   462 Florian Kammüller);
   463 
   464 * HOL/IMP: updated and converted to new-style theory format; several
   465 parts turned into readable document, with proper Isar proof texts and
   466 some explanations (by Gerwin Klein);
   467 
   468 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   469 
   470 * HOL-Hyperreal is now a logic image;
   471 
   472 
   473 *** HOLCF ***
   474 
   475 * Isar: consts/constdefs supports mixfix syntax for continuous
   476 operations;
   477 
   478 * Isar: domain package adapted to new-style theory format, e.g. see
   479 HOLCF/ex/Dnat.thy;
   480 
   481 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   482 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   483 lift.induct_tac, always use UU instead of Undef;
   484 
   485 * HOLCF/IMP: updated and converted to new-style theory;
   486 
   487 
   488 *** ZF ***
   489 
   490 * Isar: proper integration of logic-specific tools and packages,
   491 including theory commands '(co)inductive', '(co)datatype',
   492 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   493 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   494 
   495 * theory Main no longer includes AC; for the Axiom of Choice, base
   496 your theory on Main_ZFC;
   497 
   498 * the integer library now covers quotients and remainders, with many
   499 laws relating division to addition, multiplication, etc.;
   500 
   501 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   502 typeless version of the formalism;
   503 
   504 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   505 format;
   506 
   507 * ZF/Induct: new directory for examples of inductive definitions,
   508 including theory Multiset for multiset orderings; converted to
   509 new-style theory format;
   510 
   511 * ZF: many new theorems about lists, ordinals, etc.;
   512 
   513 
   514 *** General ***
   515 
   516 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   517 variable proof controls level of detail: 0 = no proofs (only oracle
   518 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   519 also ref manual for further ML interfaces;
   520 
   521 * Pure/axclass: removed obsolete ML interface
   522 goal_subclass/goal_arity;
   523 
   524 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   525 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   526 separate tokens, so expressions involving minus need to be spaced
   527 properly;
   528 
   529 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   530 rather than "infixl" or "infixr";
   531 
   532 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   533 sort constraint specifications in type inference; e.g. "x::_::foo"
   534 ensures that the type of "x" is of sort "foo" (but not necessarily a
   535 type variable);
   536 
   537 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   538 control output of nested => (types); the default behavior is
   539 "type_brackets";
   540 
   541 * Pure/syntax: builtin parse translation for "_constify" turns valued
   542 tokens into AST constants;
   543 
   544 * Pure/syntax: prefer later declarations of translations and print
   545 translation functions; potential INCOMPATIBILITY: need to reverse
   546 multiple declarations for same syntax element constant;
   547 
   548 * Pure/show_hyps reset by default (in accordance to existing Isar
   549 practice);
   550 
   551 * Provers/classical: renamed addaltern to addafter, addSaltern to
   552 addSafter;
   553 
   554 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   555 as well;
   556 
   557 * system: tested support for MacOS X; should be able to get Isabelle +
   558 Proof General to work in a plain Terminal after installing Poly/ML
   559 (e.g. from the Isabelle distribution area) and GNU bash alone
   560 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   561 support requires further installations, e.g. from
   562 http://fink.sourceforge.net/);
   563 
   564 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   565 
   566 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   567 of 40 MB), cf. ML_OPTIONS;
   568 
   569 * system: Proof General keywords specification is now part of the
   570 Isabelle distribution (see etc/isar-keywords.el);
   571 
   572 * system: support for persistent Proof General sessions (refrain from
   573 outdating all loaded theories on startup); user may create writable
   574 logic images like this: ``isabelle -q HOL Test'';
   575 
   576 * system: smart selection of Isabelle process versus Isabelle
   577 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   578 run both "isabelle" and "Isabelle" even if file names are badly
   579 damaged (executable inspects the case of the first letter of its own
   580 name); added separate "isabelle-process" and "isabelle-interface";
   581 
   582 * system: refrain from any attempt at filtering input streams; no
   583 longer support ``8bit'' encoding of old isabelle font, instead proper
   584 iso-latin characters may now be used; the related isatools
   585 "symbolinput" and "nonascii" have disappeared as well;
   586 
   587 * system: removed old "xterm" interface (the print modes "xterm" and
   588 "xterm_color" are still available for direct use in a suitable
   589 terminal);
   590 
   591 
   592 
   593 New in Isabelle99-2 (February 2001)
   594 -----------------------------------
   595 
   596 *** Overview of INCOMPATIBILITIES ***
   597 
   598 * HOL: please note that theories in the Library and elsewhere often use the
   599 new-style (Isar) format; to refer to their theorems in an ML script you must
   600 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   601 
   602 * HOL: inductive package no longer splits induction rule aggressively,
   603 but only as far as specified by the introductions given; the old
   604 format may be recovered via ML function complete_split_rule or attribute
   605 'split_rule (complete)';
   606 
   607 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   608 gfp_Tarski to gfp_unfold;
   609 
   610 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   611 
   612 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   613 relation); infix "^^" has been renamed "``"; infix "``" has been
   614 renamed "`"; "univalent" has been renamed "single_valued";
   615 
   616 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   617 operation;
   618 
   619 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   620 
   621 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   622 
   623 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   624 consequence, it is no longer monotonic wrt. the local goal context
   625 (which is now passed through the inductive cases);
   626 
   627 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   628 \<gg> to \<ggreater>;
   629 
   630 
   631 *** Document preparation ***
   632 
   633 * \isabellestyle{NAME} selects version of Isabelle output (currently
   634 available: are "it" for near math-mode best-style output, "sl" for
   635 slanted text style, and "tt" for plain type-writer; if no
   636 \isabellestyle command is given, output is according to slanted
   637 type-writer);
   638 
   639 * support sub/super scripts (for single symbols only), input syntax is
   640 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   641 
   642 * some more standard symbols; see Appendix A of the system manual for
   643 the complete list of symbols defined in isabellesym.sty;
   644 
   645 * improved isabelle style files; more abstract symbol implementation
   646 (should now use \isamath{...} and \isatext{...} in custom symbol
   647 definitions);
   648 
   649 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   650 state; Note that presentation of goal states does not conform to
   651 actual human-readable proof documents.  Please do not include goal
   652 states into document output unless you really know what you are doing!
   653 
   654 * proper indentation of antiquoted output with proportional LaTeX
   655 fonts;
   656 
   657 * no_document ML operator temporarily disables LaTeX document
   658 generation;
   659 
   660 * isatool unsymbolize tunes sources for plain ASCII communication;
   661 
   662 
   663 *** Isar ***
   664 
   665 * Pure: Isar now suffers initial goal statements to contain unbound
   666 schematic variables (this does not conform to actual readable proof
   667 documents, due to unpredictable outcome and non-compositional proof
   668 checking); users who know what they are doing may use schematic goals
   669 for Prolog-style synthesis of proven results;
   670 
   671 * Pure: assumption method (an implicit finishing) now handles actual
   672 rules as well;
   673 
   674 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   675 initial goal, declare "that" only as Pure intro (only for single
   676 steps); the "that" rule assumption may now be involved in implicit
   677 finishing, thus ".." becomes a feasible for trivial obtains;
   678 
   679 * Pure: default proof step now includes 'intro_classes'; thus trivial
   680 instance proofs may be performed by "..";
   681 
   682 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   683 statements as well;
   684 
   685 * Pure: more robust selection of calculational rules;
   686 
   687 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   688 rule (as well as the assumption rule);
   689 
   690 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   691 lemmas, using the graph browser tool;
   692 
   693 * Pure: predict failure of "show" in interactive mode;
   694 
   695 * Pure: 'thms_containing' now takes actual terms as arguments;
   696 
   697 * HOL: improved method 'induct' --- now handles non-atomic goals
   698 (potential INCOMPATIBILITY); tuned error handling;
   699 
   700 * HOL: cases and induct rules now provide explicit hints about the
   701 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   702 any remaining facts are inserted into the goal verbatim;
   703 
   704 * HOL: local contexts (aka cases) may now contain term bindings as
   705 well; the 'cases' and 'induct' methods new provide a ?case binding for
   706 the result to be shown in each case;
   707 
   708 * HOL: added 'recdef_tc' command;
   709 
   710 * isatool convert assists in eliminating legacy ML scripts;
   711 
   712 
   713 *** HOL ***
   714 
   715 * HOL/Library: a collection of generic theories to be used together
   716 with main HOL; the theory loader path already includes this directory
   717 by default; the following existing theories have been moved here:
   718 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   719 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   720 
   721 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   722 modelling and verification task performed in Isabelle/HOL +
   723 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   724 
   725 * HOL/Algebra: special summation operator SUM no longer exists, it has
   726 been replaced by setsum; infix 'assoc' now has priority 50 (like
   727 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   728 'domain', this makes the theory consistent with mathematical
   729 literature;
   730 
   731 * HOL basics: added overloaded operations "inverse" and "divide"
   732 (infix "/"), syntax for generic "abs" operation, generic summation
   733 operator \<Sum>;
   734 
   735 * HOL/typedef: simplified package, provide more useful rules (see also
   736 HOL/subset.thy);
   737 
   738 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   739 now expressed as a proper nested rule (old-style tactic scripts may
   740 require atomize_strip_tac to cope with non-atomic premises);
   741 
   742 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   743 to "split_conv" (old name still available for compatibility);
   744 
   745 * HOL: improved concrete syntax for strings (e.g. allows translation
   746 rules with string literals);
   747 
   748 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   749  and Fleuriot's mechanization of analysis, including the transcendental
   750  functions for the reals;
   751 
   752 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   753 
   754 
   755 *** CTT ***
   756 
   757 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   758 "lam" is displayed as TWO lambda-symbols
   759 
   760 * CTT: theory Main now available, containing everything (that is, Bool
   761 and Arith);
   762 
   763 
   764 *** General ***
   765 
   766 * Pure: the Simplifier has been implemented properly as a derived rule
   767 outside of the actual kernel (at last!); the overall performance
   768 penalty in practical applications is about 50%, while reliability of
   769 the Isabelle inference kernel has been greatly improved;
   770 
   771 * print modes "brackets" and "no_brackets" control output of nested =>
   772 (types) and ==> (props); the default behaviour is "brackets";
   773 
   774 * Provers: fast_tac (and friends) now handle actual object-logic rules
   775 as assumptions as well;
   776 
   777 * system: support Poly/ML 4.0;
   778 
   779 * system: isatool install handles KDE version 1 or 2;
   780 
   781 
   782 
   783 New in Isabelle99-1 (October 2000)
   784 ----------------------------------
   785 
   786 *** Overview of INCOMPATIBILITIES ***
   787 
   788 * HOL: simplification of natural numbers is much changed; to partly
   789 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   790 issue the following ML commands:
   791 
   792   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   793   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   794 
   795 * HOL: simplification no longer dives into case-expressions; this is
   796 controlled by "t.weak_case_cong" for each datatype t;
   797 
   798 * HOL: nat_less_induct renamed to less_induct;
   799 
   800 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   801 fixsome to patch .thy and .ML sources automatically;
   802 
   803   select_equality  -> some_equality
   804   select_eq_Ex     -> some_eq_ex
   805   selectI2EX       -> someI2_ex
   806   selectI2         -> someI2
   807   selectI          -> someI
   808   select1_equality -> some1_equality
   809   Eps_sym_eq       -> some_sym_eq_trivial
   810   Eps_eq           -> some_eq_trivial
   811 
   812 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   813 
   814 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   815 instead);
   816 
   817 * HOL: the recursion equations generated by 'recdef' are now called
   818 f.simps instead of f.rules;
   819 
   820 * HOL: qed_spec_mp now also handles bounded ALL as well;
   821 
   822 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   823 sometimes be needed;
   824 
   825 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   826 
   827 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   828 
   829 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   830 product is now "<*>" instead of "Times"; the lexicographic product is
   831 now "<*lex*>" instead of "**";
   832 
   833 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   834 of main HOL, but was unused); better use HOL's datatype package;
   835 
   836 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   837 the old syntax may be recovered as follows:
   838 
   839   syntax (symbols)
   840     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   841       (infixl "\\<oplus>" 100)
   842 
   843 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   844 
   845 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   846 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   847 internally;
   848 
   849 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   850 changed from A/r to A//r;
   851 
   852 * ZF: new treatment of arithmetic (nat & int) may break some old
   853 proofs;
   854 
   855 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   856 rulify -> rule_format, elimify -> elim_format, ...);
   857 
   858 * Isar/Provers: intro/elim/dest attributes changed; renamed
   859 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   860 should have to change intro!! to intro? only); replaced "delrule" by
   861 "rule del";
   862 
   863 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   864 
   865 * Provers: strengthened force_tac by using new first_best_tac;
   866 
   867 * LaTeX document preparation: several changes of isabelle.sty (see
   868 lib/texinputs);
   869 
   870 
   871 *** Document preparation ***
   872 
   873 * formal comments (text blocks etc.) in new-style theories may now
   874 contain antiquotations of thm/prop/term/typ/text to be presented
   875 according to latex print mode; concrete syntax is like this:
   876 @{term[show_types] "f(x) = a + x"};
   877 
   878 * isatool mkdir provides easy setup of Isabelle session directories,
   879 including proper document sources;
   880 
   881 * generated LaTeX sources are now deleted after successful run
   882 (isatool document -c); may retain a copy somewhere else via -D option
   883 of isatool usedir;
   884 
   885 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   886 style files, achieving self-contained LaTeX sources and simplifying
   887 LaTeX debugging;
   888 
   889 * old-style theories now produce (crude) LaTeX output as well;
   890 
   891 * browser info session directories are now self-contained (may be put
   892 on WWW server seperately); improved graphs of nested sessions; removed
   893 graph for 'all sessions';
   894 
   895 * several improvements in isabelle style files; \isabellestyle{it}
   896 produces fake math mode output; \isamarkupheader is now \section by
   897 default; see lib/texinputs/isabelle.sty etc.;
   898 
   899 
   900 *** Isar ***
   901 
   902 * Isar/Pure: local results and corresponding term bindings are now
   903 subject to Hindley-Milner polymorphism (similar to ML); this
   904 accommodates incremental type-inference very nicely;
   905 
   906 * Isar/Pure: new derived language element 'obtain' supports
   907 generalized existence reasoning;
   908 
   909 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   910 support accumulation of results, without applying any rules yet;
   911 useful to collect intermediate results without explicit name
   912 references, and for use with transitivity rules with more than 2
   913 premises;
   914 
   915 * Isar/Pure: scalable support for case-analysis type proofs: new
   916 'case' language element refers to local contexts symbolically, as
   917 produced by certain proof methods; internally, case names are attached
   918 to theorems as "tags";
   919 
   920 * Isar/Pure: theory command 'hide' removes declarations from
   921 class/type/const name spaces;
   922 
   923 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   924 indicate potential overloading;
   925 
   926 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   927 
   928 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   929 "{a,b,c}" instead of {a,b,c};
   930 
   931 * Isar/Pure now provides its own version of intro/elim/dest
   932 attributes; useful for building new logics, but beware of confusion
   933 with the version in Provers/classical;
   934 
   935 * Isar/Pure: the local context of (non-atomic) goals is provided via
   936 case name 'antecedent';
   937 
   938 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   939 to the current context is now done automatically);
   940 
   941 * Isar/Pure: theory command 'method_setup' provides a simple interface
   942 for definining proof methods in ML;
   943 
   944 * Isar/Provers: intro/elim/dest attributes changed; renamed
   945 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   946 most cases, one should have to change intro!! to intro? only);
   947 replaced "delrule" by "rule del";
   948 
   949 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   950 'symmetric' attribute (the latter supercedes [RS sym]);
   951 
   952 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   953 method modifier); 'simp' method: 'only:' modifier removes loopers as
   954 well (including splits);
   955 
   956 * Isar/Provers: Simplifier and Classical methods now support all kind
   957 of modifiers used in the past, including 'cong', 'iff', etc.
   958 
   959 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   960 of Simplifier and Classical reasoner);
   961 
   962 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   963 now support named cases; major packages (inductive, datatype, primrec,
   964 recdef) support case names and properly name parameters;
   965 
   966 * Isar/HOL: new transitivity rules for substitution in inequalities --
   967 monotonicity conditions are extracted to be proven at end of
   968 calculations;
   969 
   970 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   971 method anyway;
   972 
   973 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   974 split_if split_if_asm; datatype package provides theorems foo.splits =
   975 foo.split foo.split_asm for each datatype;
   976 
   977 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   978 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   979 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   980 use "(cases (simplified))" method in proper proof texts);
   981 
   982 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   983 
   984 * Isar: names of theorems etc. may be natural numbers as well;
   985 
   986 * Isar: 'pr' command: optional arguments for goals_limit and
   987 ProofContext.prems_limit; no longer prints theory contexts, but only
   988 proof states;
   989 
   990 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   991 additional print modes to be specified; e.g. "pr(latex)" will print
   992 proof state according to the Isabelle LaTeX style;
   993 
   994 * Isar: improved support for emulating tactic scripts, including proof
   995 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   996 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   997 (for HOL datatypes);
   998 
   999 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1000 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1001 'proof method scripts' have to be in depth-first order;
  1002 
  1003 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1004 
  1005 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1006 should instead use individual commands for printing items
  1007 (print_commands, print_methods etc.);
  1008 
  1009 * Isar: added 'nothing' --- the empty list of theorems;
  1010 
  1011 
  1012 *** HOL ***
  1013 
  1014 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1015 corresponding virtual machine and a specification of its bytecode
  1016 verifier and a lightweight bytecode verifier, including proofs of
  1017 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1018 Cornelia Pusch (see also the homepage of project Bali at
  1019 http://isabelle.in.tum.de/Bali/);
  1020 
  1021 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1022 Clemens Ballarin;
  1023 
  1024 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1025 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1026 Rasmussen;
  1027 
  1028 * HOL/Lattice: fundamental concepts of lattice theory and order
  1029 structures, including duals, properties of bounds versus algebraic
  1030 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1031 Theorem for complete lattices etc.; may also serve as a demonstration
  1032 for abstract algebraic reasoning using axiomatic type classes, and
  1033 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1034 
  1035 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1036 von Oheimb;
  1037 
  1038 * HOL/IMPP: extension of IMP with local variables and mutually
  1039 recursive procedures, by David von Oheimb;
  1040 
  1041 * HOL/Lambda: converted into new-style theory and document;
  1042 
  1043 * HOL/ex/Multiquote: example of multiple nested quotations and
  1044 anti-quotations -- basically a generalized version of de-Bruijn
  1045 representation; very useful in avoiding lifting of operations;
  1046 
  1047 * HOL/record: added general record equality rule to simpset; fixed
  1048 select-update simplification procedure to handle extended records as
  1049 well; admit "r" as field name;
  1050 
  1051 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1052 other numeric types and also as the identity of groups, rings, etc.;
  1053 
  1054 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1055 Types nat and int belong to this axclass;
  1056 
  1057 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1058    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1059    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1060   two terms #m*u and #n*u are replaced by #(m+n)*u
  1061     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1062   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1063     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1064 
  1065 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1066 powerful prover for predicate logic but knows nothing of clasets; see
  1067 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1068 
  1069 * HOL: new version of "case_tac" subsumes both boolean case split and
  1070 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1071 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1072 
  1073 * HOL: simplification no longer dives into case-expressions: only the
  1074 selector expression is simplified, but not the remaining arms; to
  1075 enable full simplification of case-expressions for datatype t, you may
  1076 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1077 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1078 
  1079 * HOL/recdef: the recursion equations generated by 'recdef' for
  1080 function 'f' are now called f.simps instead of f.rules; if all
  1081 termination conditions are proved automatically, these simplification
  1082 rules are added to the simpset, as in primrec; rules may be named
  1083 individually as well, resulting in a separate list of theorems for
  1084 each equation;
  1085 
  1086 * HOL/While is a new theory that provides a while-combinator. It
  1087 permits the definition of tail-recursive functions without the
  1088 provision of a termination measure. The latter is necessary once the
  1089 invariant proof rule for while is applied.
  1090 
  1091 * HOL: new (overloaded) notation for the set of elements below/above
  1092 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1093 
  1094 * HOL: theorems impI, allI, ballI bound as "strip";
  1095 
  1096 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1097 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1098 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1099 
  1100 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1101 
  1102 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1103 main HOL, but was unused);
  1104 
  1105 * HOL: fewer consts declared as global (e.g. have to refer to
  1106 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1107 
  1108 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1109 in case of overlap with user translations (e.g. judgements over
  1110 tuples); (note that the underlying logical represenation is still
  1111 bogus);
  1112 
  1113 
  1114 *** ZF ***
  1115 
  1116 * ZF: simplification automatically cancels common terms in arithmetic
  1117 expressions over nat and int;
  1118 
  1119 * ZF: new treatment of nat to minimize type-checking: all operators
  1120 coerce their operands to a natural number using the function natify,
  1121 making the algebraic laws unconditional;
  1122 
  1123 * ZF: as above, for int: operators coerce their operands to an integer
  1124 using the function intify;
  1125 
  1126 * ZF: the integer library now contains many of the usual laws for the
  1127 orderings, including $<=, and monotonicity laws for $+ and $*;
  1128 
  1129 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1130 simplification;
  1131 
  1132 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1133 to the simplifier and classical reasoner simultaneously;
  1134 
  1135 
  1136 *** General ***
  1137 
  1138 * Provers: blast_tac now handles actual object-logic rules as
  1139 assumptions; note that auto_tac uses blast_tac internally as well;
  1140 
  1141 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1142 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1143 
  1144 * Provers: delrules now handles destruct rules as well (no longer need
  1145 explicit make_elim);
  1146 
  1147 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1148   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1149 use instead the strong form,
  1150   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1151 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1152 from destruct-rules;
  1153 
  1154 * Provers: Simplifier.easy_setup provides a fast path to basic
  1155 Simplifier setup for new object-logics;
  1156 
  1157 * Pure: AST translation rules no longer require constant head on LHS;
  1158 
  1159 * Pure: improved name spaces: ambiguous output is qualified; support
  1160 for hiding of names;
  1161 
  1162 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1163 XSYMBOL_HOME; no longer need to do manual configuration in most
  1164 situations;
  1165 
  1166 * system: compression of ML heaps images may now be controlled via -c
  1167 option of isabelle and isatool usedir (currently only observed by
  1168 Poly/ML);
  1169 
  1170 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1171 useful for remote X11);
  1172 
  1173 * system: provide TAGS file for Isabelle sources;
  1174 
  1175 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1176 order;
  1177 
  1178 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1179 timing flag supersedes proof_timing and Toplevel.trace;
  1180 
  1181 * ML: new combinators |>> and |>>> for incremental transformations
  1182 with secondary results (e.g. certain theory extensions):
  1183 
  1184 * ML: PureThy.add_defs gets additional argument to indicate potential
  1185 overloading (usually false);
  1186 
  1187 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1188 results;
  1189 
  1190 
  1191 
  1192 New in Isabelle99 (October 1999)
  1193 --------------------------------
  1194 
  1195 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1196 
  1197 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1198 are no longer simplified.  (This allows the simplifier to unfold recursive
  1199 functional programs.)  To restore the old behaviour, declare
  1200 
  1201     Delcongs [if_weak_cong];
  1202 
  1203 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1204 complement;
  1205 
  1206 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1207 
  1208 * HOL/datatype: mutual_induct_tac no longer exists --
  1209   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1210 
  1211 * HOL/typedef: fixed type inference for representing set; type
  1212 arguments now have to occur explicitly on the rhs as type constraints;
  1213 
  1214 * ZF: The con_defs part of an inductive definition may no longer refer
  1215 to constants declared in the same theory;
  1216 
  1217 * HOL, ZF: the function mk_cases, generated by the inductive
  1218 definition package, has lost an argument.  To simplify its result, it
  1219 uses the default simpset instead of a supplied list of theorems.
  1220 
  1221 * HOL/List: the constructors of type list are now Nil and Cons;
  1222 
  1223 * Simplifier: the type of the infix ML functions
  1224         setSSolver addSSolver setSolver addSolver
  1225 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1226 for packaging solvers. A solver is created via
  1227         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1228 where the string argument is only a comment.
  1229 
  1230 
  1231 *** Proof tools ***
  1232 
  1233 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1234 decision procedure for linear arithmetic. Currently it is used for
  1235 types `nat', `int', and `real' in HOL (see below); it can, should and
  1236 will be instantiated for other types and logics as well.
  1237 
  1238 * The simplifier now accepts rewrite rules with flexible heads, eg
  1239      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1240   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1241   matching.
  1242 
  1243 
  1244 *** General ***
  1245 
  1246 * New Isabelle/Isar subsystem provides an alternative to traditional
  1247 tactical theorem proving; together with the ProofGeneral/isar user
  1248 interface it offers an interactive environment for developing human
  1249 readable proof documents (Isar == Intelligible semi-automated
  1250 reasoning); for further information see isatool doc isar-ref,
  1251 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1252 
  1253 * improved and simplified presentation of theories: better HTML markup
  1254 (including colors), graph views in several sizes; isatool usedir now
  1255 provides a proper interface for user theories (via -P option); actual
  1256 document preparation based on (PDF)LaTeX is available as well (for
  1257 new-style theories only); see isatool doc system for more information;
  1258 
  1259 * native support for Proof General, both for classic Isabelle and
  1260 Isabelle/Isar;
  1261 
  1262 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1263 using the graph browser tool;
  1264 
  1265 * Isabelle manuals now also available as PDF;
  1266 
  1267 * theory loader rewritten from scratch (may not be fully
  1268 bug-compatible); old loadpath variable has been replaced by show_path,
  1269 add_path, del_path, reset_path functions; new operations such as
  1270 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1271 isatool doc ref);
  1272 
  1273 * improved isatool install: option -k creates KDE application icon,
  1274 option -p DIR installs standalone binaries;
  1275 
  1276 * added ML_PLATFORM setting (useful for cross-platform installations);
  1277 more robust handling of platform specific ML images for SML/NJ;
  1278 
  1279 * the settings environment is now statically scoped, i.e. it is never
  1280 created again in sub-processes invoked from isabelle, isatool, or
  1281 Isabelle;
  1282 
  1283 * path element specification '~~' refers to '$ISABELLE_HOME';
  1284 
  1285 * in locales, the "assumes" and "defines" parts may be omitted if
  1286 empty;
  1287 
  1288 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1289 long arrows);
  1290 
  1291 * new print_mode "HTML";
  1292 
  1293 * new flag show_tags controls display of tags of theorems (which are
  1294 basically just comments that may be attached by some tools);
  1295 
  1296 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1297 mode and goal output format:
  1298 
  1299 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1300 244c244
  1301 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1302 ---
  1303 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1304 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1305 181c181
  1306 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1307 ---
  1308 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1309 
  1310 * function bind_thms stores lists of theorems (cf. bind_thm);
  1311 
  1312 * new shorthand tactics ftac, eatac, datac, fatac;
  1313 
  1314 * qed (and friends) now accept "" as result name; in that case the
  1315 theorem is not stored, but proper checks and presentation of the
  1316 result still apply;
  1317 
  1318 * theorem database now also indexes constants "Trueprop", "all",
  1319 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1320 
  1321 
  1322 *** HOL ***
  1323 
  1324 ** HOL arithmetic **
  1325 
  1326 * There are now decision procedures for linear arithmetic over nat and
  1327 int:
  1328 
  1329 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1330 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1331 are treated as atomic; subformulae not involving type `nat' or `int'
  1332 are ignored; quantified subformulae are ignored unless they are
  1333 positive universal or negative existential. The tactic has to be
  1334 invoked by hand and can be a little bit slow. In particular, the
  1335 running time is exponential in the number of occurrences of `min' and
  1336 `max', and `-' on `nat'.
  1337 
  1338 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1339 (negated) (in)equalities among the premises and the conclusion into
  1340 account (i.e. no compound formulae) and does not know about `min' and
  1341 `max', and `-' on `nat'. It is fast and is used automatically by the
  1342 simplifier.
  1343 
  1344 NB: At the moment, these decision procedures do not cope with mixed
  1345 nat/int formulae where the two parts interact, such as `m < n ==>
  1346 int(m) < int(n)'.
  1347 
  1348 * HOL/Numeral provides a generic theory of numerals (encoded
  1349 efficiently as bit strings); setup for types nat/int/real is in place;
  1350 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1351 int, existing theories and proof scripts may require a few additional
  1352 type constraints;
  1353 
  1354 * integer division and remainder can now be performed on constant
  1355 arguments;
  1356 
  1357 * many properties of integer multiplication, division and remainder
  1358 are now available;
  1359 
  1360 * An interface to the Stanford Validity Checker (SVC) is available through the
  1361 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1362 are proved automatically.  SVC must be installed separately, and its results
  1363 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1364 invocation of the underlying oracle).  For SVC see
  1365   http://verify.stanford.edu/SVC
  1366 
  1367 * IsaMakefile: the HOL-Real target now builds an actual image;
  1368 
  1369 
  1370 ** HOL misc **
  1371 
  1372 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1373 (in Isabelle/Isar) -- by Gertrud Bauer;
  1374 
  1375 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1376 analysis for assembly languages with subtypes;
  1377 
  1378 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1379 -- avoids syntactic ambiguities and treats state, transition, and
  1380 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1381 changed syntax and (many) tactics;
  1382 
  1383 * HOL/inductive: Now also handles more general introduction rules such
  1384   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1385   theorems are now maintained within the theory (maintained via the
  1386   "mono" attribute);
  1387 
  1388 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1389   (using function types) such as
  1390 
  1391   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1392 
  1393 * HOL/record: record_simproc (part of the default simpset) takes care
  1394 of selectors applied to updated records; record_split_tac is no longer
  1395 part of the default claset; update_defs may now be removed from the
  1396 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1397 
  1398   claset_ref () := claset() addSWrapper record_split_wrapper;
  1399   Delsimprocs [record_simproc]
  1400 
  1401 * HOL/typedef: fixed type inference for representing set; type
  1402 arguments now have to occur explicitly on the rhs as type constraints;
  1403 
  1404 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1405 names rather than an ML expression;
  1406 
  1407 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1408 supplied later.  Program schemes can be defined, such as
  1409     "While B C s = (if B s then While B C (C s) else s)"
  1410 where the well-founded relation can be chosen after B and C have been given.
  1411 
  1412 * HOL/List: the constructors of type list are now Nil and Cons;
  1413 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1414 course, ML tools referring to List.list.op # etc. have to be adapted;
  1415 
  1416 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1417 disabled by default; run isabelle with option -m HOL to get back to
  1418 the original Gordon/HOL-style output;
  1419 
  1420 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1421 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1422 
  1423 * HOL basic syntax simplified (more orthogonal): all variants of
  1424 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1425 Eps operator is provided as well: "SOME x. P[x]";
  1426 
  1427 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1428 
  1429 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1430 thus available for user theories;
  1431 
  1432 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1433 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1434 time;
  1435 
  1436 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1437 several times and then mp;
  1438 
  1439 
  1440 *** LK ***
  1441 
  1442 * the notation <<...>> is now available as a notation for sequences of
  1443 formulas;
  1444 
  1445 * the simplifier is now installed
  1446 
  1447 * the axiom system has been generalized (thanks to Soren Heilmann)
  1448 
  1449 * the classical reasoner now has a default rule database
  1450 
  1451 
  1452 *** ZF ***
  1453 
  1454 * new primrec section allows primitive recursive functions to be given
  1455 directly (as in HOL) over datatypes and the natural numbers;
  1456 
  1457 * new tactics induct_tac and exhaust_tac for induction (or case
  1458 analysis) over datatypes and the natural numbers;
  1459 
  1460 * the datatype declaration of type T now defines the recursor T_rec;
  1461 
  1462 * simplification automatically does freeness reasoning for datatype
  1463 constructors;
  1464 
  1465 * automatic type-inference, with AddTCs command to insert new
  1466 type-checking rules;
  1467 
  1468 * datatype introduction rules are now added as Safe Introduction rules
  1469 to the claset;
  1470 
  1471 * the syntax "if P then x else y" is now available in addition to
  1472 if(P,x,y);
  1473 
  1474 
  1475 *** Internal programming interfaces ***
  1476 
  1477 * tuned simplifier trace output; new flag debug_simp;
  1478 
  1479 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1480 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1481 
  1482 * AxClass.axclass_tac lost the theory argument;
  1483 
  1484 * tuned current_goals_markers semantics: begin / end goal avoids
  1485 printing empty lines;
  1486 
  1487 * removed prs and prs_fn hook, which was broken because it did not
  1488 include \n in its semantics, forcing writeln to add one
  1489 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1490 string -> unit if you really want to output text without newline;
  1491 
  1492 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1493 plain output, interface builders may have to enable 'isabelle_font'
  1494 mode to get Isabelle font glyphs as before;
  1495 
  1496 * refined token_translation interface; INCOMPATIBILITY: output length
  1497 now of type real instead of int;
  1498 
  1499 * theory loader actions may be traced via new ThyInfo.add_hook
  1500 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1501 your own database of information attached to *whole* theories -- as
  1502 opposed to intra-theory data slots offered via TheoryDataFun;
  1503 
  1504 * proper handling of dangling sort hypotheses (at last!);
  1505 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1506 extra sort hypotheses that can be witnessed from the type signature;
  1507 the force_strip_shyps flag is gone, any remaining shyps are simply
  1508 left in the theorem (with a warning issued by strip_shyps_warning);
  1509 
  1510 
  1511 
  1512 New in Isabelle98-1 (October 1998)
  1513 ----------------------------------
  1514 
  1515 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1516 
  1517 * several changes of automated proof tools;
  1518 
  1519 * HOL: major changes to the inductive and datatype packages, including
  1520 some minor incompatibilities of theory syntax;
  1521 
  1522 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1523 called `inj_on';
  1524 
  1525 * HOL: removed duplicate thms in Arith:
  1526   less_imp_add_less  should be replaced by  trans_less_add1
  1527   le_imp_add_le      should be replaced by  trans_le_add1
  1528 
  1529 * HOL: unary minus is now overloaded (new type constraints may be
  1530 required);
  1531 
  1532 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1533 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1534 now taken as an integer constant.
  1535 
  1536 * Pure: ML function 'theory_of' renamed to 'theory';
  1537 
  1538 
  1539 *** Proof tools ***
  1540 
  1541 * Simplifier:
  1542   1. Asm_full_simp_tac is now more aggressive.
  1543      1. It will sometimes reorient premises if that increases their power to
  1544         simplify.
  1545      2. It does no longer proceed strictly from left to right but may also
  1546         rotate premises to achieve further simplification.
  1547      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1548      old Asm_full_simp_tac in that it does not rotate premises.
  1549   2. The simplifier now knows a little bit about nat-arithmetic.
  1550 
  1551 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1552 allows for selected deletion of wrappers, by introduction of names for
  1553 wrapper functionals.  This implies that addbefore, addSbefore,
  1554 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1555 and that adding two tactics with the same name overwrites the first
  1556 one (emitting a warning).
  1557   type wrapper = (int -> tactic) -> (int -> tactic)
  1558   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1559   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1560   delWrapper, delSWrapper: claset *  string            -> claset
  1561   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1562 
  1563 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1564 semantics; addbefore now affects only the unsafe part of step_tac
  1565 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1566 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1567 by Force_tac;
  1568 
  1569 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1570 compWrapper; added safe wrapper (and access functions for it);
  1571 
  1572 * HOL/split_all_tac is now much faster and fails if there is nothing
  1573 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1574 and the names of the automatically generated variables have changed.
  1575 split_all_tac has moved within claset() from unsafe wrappers to safe
  1576 wrappers, which means that !!-bound variables are split much more
  1577 aggressively, and safe_tac and clarify_tac now split such variables.
  1578 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1579 Note: the same holds for record_split_tac, which does the job of
  1580 split_all_tac for record fields.
  1581 
  1582 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1583 permanently to the default simpset using Addsplits just like
  1584 Addsimps. They can be removed via Delsplits just like
  1585 Delsimps. Lower-case versions are also available.
  1586 
  1587 * HOL/Simplifier: The rule split_if is now part of the default
  1588 simpset. This means that the simplifier will eliminate all occurrences
  1589 of if-then-else in the conclusion of a goal. To prevent this, you can
  1590 either remove split_if completely from the default simpset by
  1591 `Delsplits [split_if]' or remove it in a specific call of the
  1592 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1593 other case splitting rules to/from the default simpset: every datatype
  1594 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1595 t is the name of the datatype).
  1596 
  1597 * Classical reasoner / Simplifier combination: new force_tac (and
  1598 derivatives Force_tac, force) combines rewriting and classical
  1599 reasoning (and whatever other tools) similarly to auto_tac, but is
  1600 aimed to solve the given subgoal completely.
  1601 
  1602 
  1603 *** General ***
  1604 
  1605 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1606 and `goalw': the theory is no longer needed as an explicit argument -
  1607 the current theory context is used; assumptions are no longer returned
  1608 at the ML-level unless one of them starts with ==> or !!; it is
  1609 recommended to convert to these new commands using isatool fixgoal
  1610 (backup your sources first!);
  1611 
  1612 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1613 the current theory context, and 'theory' to lookup stored theories;
  1614 
  1615 * new theory section 'locale' for declaring constants, assumptions and
  1616 definitions that have local scope;
  1617 
  1618 * new theory section 'nonterminals' for purely syntactic types;
  1619 
  1620 * new theory section 'setup' for generic ML setup functions
  1621 (e.g. package initialization);
  1622 
  1623 * the distribution now includes Isabelle icons: see
  1624 lib/logo/isabelle-{small,tiny}.xpm;
  1625 
  1626 * isatool install - install binaries with absolute references to
  1627 ISABELLE_HOME/bin;
  1628 
  1629 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1630 
  1631 * print mode 'emacs' reserved for Isamode;
  1632 
  1633 * support multiple print (ast) translations per constant name;
  1634 
  1635 * theorems involving oracles are now printed with a suffixed [!];
  1636 
  1637 
  1638 *** HOL ***
  1639 
  1640 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1641 
  1642 * HOL/inductive package reorganized and improved: now supports mutual
  1643 definitions such as
  1644 
  1645   inductive EVEN ODD
  1646     intrs
  1647       null "0 : EVEN"
  1648       oddI "n : EVEN ==> Suc n : ODD"
  1649       evenI "n : ODD ==> Suc n : EVEN"
  1650 
  1651 new theorem list "elims" contains an elimination rule for each of the
  1652 recursive sets; inductive definitions now handle disjunctive premises
  1653 correctly (also ZF);
  1654 
  1655 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1656 "mutual_induct" no longer exists - the induction rule is always
  1657 contained in "induct";
  1658 
  1659 
  1660 * HOL/datatype package re-implemented and greatly improved: now
  1661 supports mutually recursive datatypes such as
  1662 
  1663   datatype
  1664     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1665             | SUM ('a aexp) ('a aexp)
  1666             | DIFF ('a aexp) ('a aexp)
  1667             | NUM 'a
  1668   and
  1669     'a bexp = LESS ('a aexp) ('a aexp)
  1670             | AND ('a bexp) ('a bexp)
  1671             | OR ('a bexp) ('a bexp)
  1672 
  1673 as well as indirectly recursive datatypes such as
  1674 
  1675   datatype
  1676     ('a, 'b) term = Var 'a
  1677                   | App 'b ((('a, 'b) term) list)
  1678 
  1679 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1680 induction on mutually / indirectly recursive datatypes.
  1681 
  1682 Primrec equations are now stored in theory and can be accessed via
  1683 <function_name>.simps.
  1684 
  1685 INCOMPATIBILITIES:
  1686 
  1687   - Theories using datatypes must now have theory Datatype as an
  1688     ancestor.
  1689   - The specific <typename>.induct_tac no longer exists - use the
  1690     generic induct_tac instead.
  1691   - natE has been renamed to nat.exhaust - use exhaust_tac
  1692     instead of res_inst_tac ... natE. Note that the variable
  1693     names in nat.exhaust differ from the names in natE, this
  1694     may cause some "fragile" proofs to fail.
  1695   - The theorems split_<typename>_case and split_<typename>_case_asm
  1696     have been renamed to <typename>.split and <typename>.split_asm.
  1697   - Since default sorts of type variables are now handled correctly,
  1698     some datatype definitions may have to be annotated with explicit
  1699     sort constraints.
  1700   - Primrec definitions no longer require function name and type
  1701     of recursive argument.
  1702 
  1703 Consider using isatool fixdatatype to adapt your theories and proof
  1704 scripts to the new package (backup your sources first!).
  1705 
  1706 
  1707 * HOL/record package: considerably improved implementation; now
  1708 includes concrete syntax for record types, terms, updates; theorems
  1709 for surjective pairing and splitting !!-bound record variables; proof
  1710 support is as follows:
  1711 
  1712   1) standard conversions (selectors or updates applied to record
  1713 constructor terms) are part of the standard simpset;
  1714 
  1715   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1716 made part of standard simpset and claset via addIffs;
  1717 
  1718   3) a tactic for record field splitting (record_split_tac) is part of
  1719 the standard claset (addSWrapper);
  1720 
  1721 To get a better idea about these rules you may retrieve them via
  1722 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1723 the name of your record type.
  1724 
  1725 The split tactic 3) conceptually simplifies by the following rule:
  1726 
  1727   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1728 
  1729 Thus any record variable that is bound by meta-all will automatically
  1730 blow up into some record constructor term, consequently the
  1731 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1732 solve record problems automatically.
  1733 
  1734 
  1735 * reorganized the main HOL image: HOL/Integ and String loaded by
  1736 default; theory Main includes everything;
  1737 
  1738 * automatic simplification of integer sums and comparisons, using cancellation;
  1739 
  1740 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1741 
  1742 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1743 
  1744 * many new identities for unions, intersections, set difference, etc.;
  1745 
  1746 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1747 called split_if, split_split, split_sum_case and split_nat_case (to go
  1748 with add/delsplits);
  1749 
  1750 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1751 (?x::unit) = (); this is made part of the default simpset, which COULD
  1752 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1753 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1754 unit_abs_eta_conv is added in order to counter the effect of
  1755 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1756 %u.f();
  1757 
  1758 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1759 makes more sense);
  1760 
  1761 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1762   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1763   disjointness reasoning but breaking a few old proofs.
  1764 
  1765 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1766 to 'converse' from 'inverse' (for compatibility with ZF and some
  1767 literature);
  1768 
  1769 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1770 the well-founded relation;
  1771 
  1772 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1773     Compl A.  The "Compl" syntax remains available as input syntax for this
  1774     release ONLY.
  1775 
  1776 * HOL/Update: new theory of function updates:
  1777     f(a:=b) == %x. if x=a then b else f x
  1778 may also be iterated as in f(a:=b,c:=d,...);
  1779 
  1780 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1781 
  1782 * HOL/List:
  1783   - new function list_update written xs[i:=v] that updates the i-th
  1784     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1785   - new function `upt' written [i..j(] which generates the list
  1786     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1787     bound write [i..j], which is a shorthand for [i..j+1(].
  1788   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1789 
  1790 * HOL/Arith:
  1791   - removed 'pred' (predecessor) function;
  1792   - generalized some theorems about n-1;
  1793   - many new laws about "div" and "mod";
  1794   - new laws about greatest common divisors (see theory ex/Primes);
  1795 
  1796 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1797 instead of "inverse";
  1798 
  1799 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1800   of the multiset ordering;
  1801 
  1802 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1803   (not included by default);
  1804 
  1805 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1806 
  1807 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1808   programs, i.e. different program variables may have different types.
  1809 
  1810 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1811   [previously, this check worked only if the rewrite rule was unconditional]
  1812   Now rew can involve either definitions or equalities (either == or =).
  1813 
  1814 
  1815 *** ZF ***
  1816 
  1817 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1818   only the theorems proved on ZF.ML;
  1819 
  1820 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1821   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1822   disjointness reasoning but breaking a few old proofs.
  1823 
  1824 * ZF/Update: new theory of function updates
  1825     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1826   may also be iterated as in f(a:=b,c:=d,...);
  1827 
  1828 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1829 
  1830 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1831   [previously, this check worked only if the rewrite rule was unconditional]
  1832   Now rew can involve either definitions or equalities (either == or =).
  1833 
  1834 * case_tac provided for compatibility with HOL
  1835     (like the old excluded_middle_tac, but with subgoals swapped)
  1836 
  1837 
  1838 *** Internal programming interfaces ***
  1839 
  1840 * Pure: several new basic modules made available for general use, see
  1841 also src/Pure/README;
  1842 
  1843 * improved the theory data mechanism to support encapsulation (data
  1844 kind name replaced by private Object.kind, acting as authorization
  1845 key); new type-safe user interface via functor TheoryDataFun; generic
  1846 print_data function becomes basically useless;
  1847 
  1848 * removed global_names compatibility flag -- all theory declarations
  1849 are qualified by default;
  1850 
  1851 * module Pure/Syntax now offers quote / antiquote translation
  1852 functions (useful for Hoare logic etc. with implicit dependencies);
  1853 see HOL/ex/Antiquote for an example use;
  1854 
  1855 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1856 cterm -> thm;
  1857 
  1858 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1859 subgoal;
  1860 
  1861 * Display.print_goals function moved to Locale.print_goals;
  1862 
  1863 * standard print function for goals supports current_goals_markers
  1864 variable for marking begin of proof, end of proof, start of goal; the
  1865 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1866 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1867 for example;
  1868 
  1869 
  1870 
  1871 New in Isabelle98 (January 1998)
  1872 --------------------------------
  1873 
  1874 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1875 
  1876 * changed lexical syntax of terms / types: dots made part of long
  1877 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1878 
  1879 * simpset (and claset) reference variable replaced by functions
  1880 simpset / simpset_ref;
  1881 
  1882 * no longer supports theory aliases (via merge) and non-trivial
  1883 implicit merge of thms' signatures;
  1884 
  1885 * most internal names of constants changed due to qualified names;
  1886 
  1887 * changed Pure/Sequence interface (see Pure/seq.ML);
  1888 
  1889 
  1890 *** General Changes ***
  1891 
  1892 * hierachically structured name spaces (for consts, types, axms, thms
  1893 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1894 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1895 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1896 long_names for fully qualified output names; NOTE: ML programs
  1897 (special tactics, packages etc.) referring to internal names may have
  1898 to be adapted to cope with fully qualified names; in case of severe
  1899 backward campatibility problems try setting 'global_names' at compile
  1900 time to have enrything declared within a flat name space; one may also
  1901 fine tune name declarations in theories via the 'global' and 'local'
  1902 section;
  1903 
  1904 * reimplemented the implicit simpset and claset using the new anytype
  1905 data filed in signatures; references simpset:simpset ref etc. are
  1906 replaced by functions simpset:unit->simpset and
  1907 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1908 to patch your ML files accordingly;
  1909 
  1910 * HTML output now includes theory graph data for display with Java
  1911 applet or isatool browser; data generated automatically via isatool
  1912 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1913 
  1914 * defs may now be conditional; improved rewrite_goals_tac to handle
  1915 conditional equations;
  1916 
  1917 * defs now admits additional type arguments, using TYPE('a) syntax;
  1918 
  1919 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1920 creates a new theory node; implicit merge of thms' signatures is
  1921 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1922 transfer:theory->thm->thm in (rare) cases;
  1923 
  1924 * improved handling of draft signatures / theories; draft thms (and
  1925 ctyps, cterms) are automatically promoted to real ones;
  1926 
  1927 * slightly changed interfaces for oracles: admit many per theory, named
  1928 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1929 
  1930 * print_goals: optional output of const types (set show_consts and
  1931 show_types);
  1932 
  1933 * improved output of warnings (###) and errors (***);
  1934 
  1935 * subgoal_tac displays a warning if the new subgoal has type variables;
  1936 
  1937 * removed old README and Makefiles;
  1938 
  1939 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1940 
  1941 * removed obsolete init_pps and init_database;
  1942 
  1943 * deleted the obsolete tactical STATE, which was declared by
  1944     fun STATE tacfun st = tacfun st st;
  1945 
  1946 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1947 (which abbreviates $HOME);
  1948 
  1949 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1950 use isatool fixseq to adapt your ML programs (this works for fully
  1951 qualified references to the Sequence structure only!);
  1952 
  1953 * use_thy no longer requires writable current directory; it always
  1954 reloads .ML *and* .thy file, if either one is out of date;
  1955 
  1956 
  1957 *** Classical Reasoner ***
  1958 
  1959 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1960 tactics that use classical reasoning to simplify a subgoal without
  1961 splitting it into several subgoals;
  1962 
  1963 * Safe_tac: like safe_tac but uses the default claset;
  1964 
  1965 
  1966 *** Simplifier ***
  1967 
  1968 * added simplification meta rules:
  1969     (asm_)(full_)simplify: simpset -> thm -> thm;
  1970 
  1971 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1972 logics (again);
  1973 
  1974 * added prems argument to simplification procedures;
  1975 
  1976 * HOL, FOL, ZF: added infix function `addsplits':
  1977   instead of `<simpset> setloop (split_tac <thms>)'
  1978   you can simply write `<simpset> addsplits <thms>'
  1979 
  1980 
  1981 *** Syntax ***
  1982 
  1983 * TYPE('a) syntax for type reflection terms;
  1984 
  1985 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1986 
  1987 * pretty printer: changed order of mixfix annotation preference (again!);
  1988 
  1989 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1990 
  1991 
  1992 *** HOL ***
  1993 
  1994 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1995   with `addloop' of the simplifier to faciliate case splitting in premises.
  1996 
  1997 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1998 
  1999 * HOL/Auth: new protocol proofs including some for the Internet
  2000   protocol TLS;
  2001 
  2002 * HOL/Map: new theory of `maps' a la VDM;
  2003 
  2004 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2005 cancelling out common nat summands from =, <, <= (in)equalities, or
  2006 differences; simplification procedures nat_cancel_factor for
  2007 cancelling common factor from =, <, <= (in)equalities over natural
  2008 sums; nat_cancel contains both kinds of procedures, it is installed by
  2009 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2010 
  2011 * HOL/simplifier: terms of the form
  2012   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2013   are rewritten to
  2014   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2015   and those of the form
  2016   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2017   are rewritten to
  2018   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2019 
  2020 * HOL/datatype
  2021   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2022 
  2023   P(t_case f1 ... fn x) =
  2024      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2025         ...
  2026        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2027      )
  2028 
  2029   and a theorem `split_t_case_asm' of the form
  2030 
  2031   P(t_case f1 ... fn x) =
  2032     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2033         ...
  2034        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2035      )
  2036   which can be added to a simpset via `addsplits'. The existing theorems
  2037   expand_list_case and expand_option_case have been renamed to
  2038   split_list_case and split_option_case.
  2039 
  2040 * HOL/Arithmetic:
  2041   - `pred n' is automatically converted to `n-1'.
  2042     Users are strongly encouraged not to use `pred' any longer,
  2043     because it will disappear altogether at some point.
  2044   - Users are strongly encouraged to write "0 < n" rather than
  2045     "n ~= 0". Theorems and proof tools have been modified towards this
  2046     `standard'.
  2047 
  2048 * HOL/Lists:
  2049   the function "set_of_list" has been renamed "set" (and its theorems too);
  2050   the function "nth" now takes its arguments in the reverse order and
  2051   has acquired the infix notation "!" as in "xs!n".
  2052 
  2053 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2054 
  2055 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2056   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2057 
  2058 * HOL/record: extensible records with schematic structural subtyping
  2059 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2060 still lacks various theorems and concrete record syntax;
  2061 
  2062 
  2063 *** HOLCF ***
  2064 
  2065 * removed "axioms" and "generated by" sections;
  2066 
  2067 * replaced "ops" section by extended "consts" section, which is capable of
  2068   handling the continuous function space "->" directly;
  2069 
  2070 * domain package:
  2071   . proves theorems immediately and stores them in the theory,
  2072   . creates hierachical name space,
  2073   . now uses normal mixfix annotations (instead of cinfix...),
  2074   . minor changes to some names and values (for consistency),
  2075   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2076   . separator between mutual domain defs: changed "," to "and",
  2077   . improved handling of sort constraints;  now they have to
  2078     appear on the left-hand side of the equations only;
  2079 
  2080 * fixed LAM <x,y,zs>.b syntax;
  2081 
  2082 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2083 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2084 
  2085 
  2086 *** FOL and ZF ***
  2087 
  2088 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2089   with `addloop' of the simplifier to faciliate case splitting in premises.
  2090 
  2091 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2092 in HOL, they strip ALL and --> from proved theorems;
  2093 
  2094 
  2095 
  2096 New in Isabelle94-8 (May 1997)
  2097 ------------------------------
  2098 
  2099 *** General Changes ***
  2100 
  2101 * new utilities to build / run / maintain Isabelle etc. (in parts
  2102 still somewhat experimental); old Makefiles etc. still functional;
  2103 
  2104 * new 'Isabelle System Manual';
  2105 
  2106 * INSTALL text, together with ./configure and ./build scripts;
  2107 
  2108 * reimplemented type inference for greater efficiency, better error
  2109 messages and clean internal interface;
  2110 
  2111 * prlim command for dealing with lots of subgoals (an easier way of
  2112 setting goals_limit);
  2113 
  2114 
  2115 *** Syntax ***
  2116 
  2117 * supports alternative (named) syntax tables (parser and pretty
  2118 printer); internal interface is provided by add_modesyntax(_i);
  2119 
  2120 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2121 be used in conjunction with the Isabelle symbol font; uses the
  2122 "symbols" syntax table;
  2123 
  2124 * added token_translation interface (may translate name tokens in
  2125 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2126 the current print_mode); IMPORTANT: user print translation functions
  2127 are responsible for marking newly introduced bounds
  2128 (Syntax.mark_boundT);
  2129 
  2130 * token translations for modes "xterm" and "xterm_color" that display
  2131 names in bold, underline etc. or colors (which requires a color
  2132 version of xterm);
  2133 
  2134 * infixes may now be declared with names independent of their syntax;
  2135 
  2136 * added typed_print_translation (like print_translation, but may
  2137 access type of constant);
  2138 
  2139 
  2140 *** Classical Reasoner ***
  2141 
  2142 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2143 some limitations.  Blast_tac...
  2144   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2145   + ignores elimination rules that don't have the correct format
  2146         (the conclusion MUST be a formula variable)
  2147   + ignores types, which can make HOL proofs fail
  2148   + rules must not require higher-order unification, e.g. apply_type in ZF
  2149     [message "Function Var's argument not a bound variable" relates to this]
  2150   + its proof strategy is more general but can actually be slower
  2151 
  2152 * substitution with equality assumptions no longer permutes other
  2153 assumptions;
  2154 
  2155 * minor changes in semantics of addafter (now called addaltern); renamed
  2156 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2157 (and access functions for it);
  2158 
  2159 * improved combination of classical reasoner and simplifier:
  2160   + functions for handling clasimpsets
  2161   + improvement of addss: now the simplifier is called _after_ the
  2162     safe steps.
  2163   + safe variant of addss called addSss: uses safe simplifications
  2164     _during_ the safe steps. It is more complete as it allows multiple
  2165     instantiations of unknowns (e.g. with slow_tac).
  2166 
  2167 *** Simplifier ***
  2168 
  2169 * added interface for simplification procedures (functions that
  2170 produce *proven* rewrite rules on the fly, depending on current
  2171 redex);
  2172 
  2173 * ordering on terms as parameter (used for ordered rewriting);
  2174 
  2175 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2176 
  2177 * the solver is now split into a safe and an unsafe part.
  2178 This should be invisible for the normal user, except that the
  2179 functions setsolver and addsolver have been renamed to setSolver and
  2180 addSolver; added safe_asm_full_simp_tac;
  2181 
  2182 
  2183 *** HOL ***
  2184 
  2185 * a generic induction tactic `induct_tac' which works for all datatypes and
  2186 also for type `nat';
  2187 
  2188 * a generic case distinction tactic `exhaust_tac' which works for all
  2189 datatypes and also for type `nat';
  2190 
  2191 * each datatype comes with a function `size';
  2192 
  2193 * patterns in case expressions allow tuple patterns as arguments to
  2194 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2195 
  2196 * primrec now also works with type nat;
  2197 
  2198 * recdef: a new declaration form, allows general recursive functions to be
  2199 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2200 
  2201 * the constant for negation has been renamed from "not" to "Not" to
  2202 harmonize with FOL, ZF, LK, etc.;
  2203 
  2204 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2205 infinite lists;
  2206 
  2207 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2208 
  2209 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2210 problems in commutative rings, using axiomatic type classes for + and *;
  2211 
  2212 * more examples in HOL/MiniML and HOL/Auth;
  2213 
  2214 * more default rewrite rules for quantifiers, union/intersection;
  2215 
  2216 * a new constant `arbitrary == @x.False';
  2217 
  2218 * HOLCF/IOA replaces old HOL/IOA;
  2219 
  2220 * HOLCF changes: derived all rules and arities
  2221   + axiomatic type classes instead of classes
  2222   + typedef instead of faking type definitions
  2223   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2224   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2225   + eliminated the types void, one, tr
  2226   + use unit lift and bool lift (with translations) instead of one and tr
  2227   + eliminated blift from Lift3.thy (use Def instead of blift)
  2228   all eliminated rules are derived as theorems --> no visible changes ;
  2229 
  2230 
  2231 *** ZF ***
  2232 
  2233 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2234 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2235 as ZF_cs addSIs [equalityI];
  2236 
  2237 
  2238 
  2239 New in Isabelle94-7 (November 96)
  2240 ---------------------------------
  2241 
  2242 * allowing negative levels (as offsets) in prlev and choplev;
  2243 
  2244 * super-linear speedup for large simplifications;
  2245 
  2246 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2247 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2248 FAIL); can suppress it using the command Delsimps (ex_simps @
  2249 all_simps); De Morgan laws are also now included, by default;
  2250 
  2251 * improved printing of ==>  :  ~:
  2252 
  2253 * new object-logic "Sequents" adds linear logic, while replacing LK
  2254 and Modal (thanks to Sara Kalvala);
  2255 
  2256 * HOL/Auth: correctness proofs for authentication protocols;
  2257 
  2258 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2259 examples on HOL/Auth);
  2260 
  2261 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2262 the rewriter and classical reasoner simultaneously;
  2263 
  2264 * function uresult no longer returns theorems in "standard" format;
  2265 regain previous version by: val uresult = standard o uresult;
  2266 
  2267 
  2268 
  2269 New in Isabelle94-6
  2270 -------------------
  2271 
  2272 * oracles -- these establish an interface between Isabelle and trusted
  2273 external reasoners, which may deliver results as theorems;
  2274 
  2275 * proof objects (in particular record all uses of oracles);
  2276 
  2277 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2278 
  2279 * "constdefs" section in theory files;
  2280 
  2281 * "primrec" section (HOL) no longer requires names;
  2282 
  2283 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2284 
  2285 
  2286 
  2287 New in Isabelle94-5
  2288 -------------------
  2289 
  2290 * reduced space requirements;
  2291 
  2292 * automatic HTML generation from theories;
  2293 
  2294 * theory files no longer require "..." (quotes) around most types;
  2295 
  2296 * new examples, including two proofs of the Church-Rosser theorem;
  2297 
  2298 * non-curried (1994) version of HOL is no longer distributed;
  2299 
  2300 
  2301 
  2302 New in Isabelle94-4
  2303 -------------------
  2304 
  2305 * greatly reduced space requirements;
  2306 
  2307 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2308 
  2309 * searchable theorem database (see the section "Retrieving theorems" on
  2310 page 8 of the Reference Manual);
  2311 
  2312 * new examples, including Grabczewski's monumental case study of the
  2313 Axiom of Choice;
  2314 
  2315 * The previous version of HOL renamed to Old_HOL;
  2316 
  2317 * The new version of HOL (previously called CHOL) uses a curried syntax
  2318 for functions.  Application looks like f a b instead of f(a,b);
  2319 
  2320 * Mutually recursive inductive definitions finally work in HOL;
  2321 
  2322 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2323 translates to the operator "split";
  2324 
  2325 
  2326 
  2327 New in Isabelle94-3
  2328 -------------------
  2329 
  2330 * new infix operator, addss, allowing the classical reasoner to
  2331 perform simplification at each step of its search.  Example:
  2332         fast_tac (cs addss ss)
  2333 
  2334 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2335 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2336 look like (a,b) instead of <a,b>;
  2337 
  2338 * PLEASE NOTE: CHOL will eventually replace HOL!
  2339 
  2340 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2341 It translates to the operator "split".  A new theory of integers is available;
  2342 
  2343 * In ZF, integer numerals now denote two's-complement binary integers.
  2344 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2345 
  2346 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2347 of the Axiom of Choice;
  2348 
  2349 
  2350 
  2351 New in Isabelle94-2
  2352 -------------------
  2353 
  2354 * Significantly faster resolution;
  2355 
  2356 * the different sections in a .thy file can now be mixed and repeated
  2357 freely;
  2358 
  2359 * Database of theorems for FOL, HOL and ZF.  New
  2360 commands including qed, qed_goal and bind_thm store theorems in the database.
  2361 
  2362 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2363 a given theory (thms_of), or find out what theory a theorem was proved in
  2364 (theory_of_thm);
  2365 
  2366 * Bugs fixed in the inductive definition and datatype packages;
  2367 
  2368 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2369 and HOL_dup_cs obsolete;
  2370 
  2371 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2372 have been removed;
  2373 
  2374 * Simpler definition of function space in ZF;
  2375 
  2376 * new results about cardinal and ordinal arithmetic in ZF;
  2377 
  2378 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2379 types;
  2380 
  2381 
  2382 $Id$