NEWS
author paulson
Tue Sep 23 15:40:27 2003 +0200 (2003-09-23)
changeset 14199 d3b8d972a488
parent 14175 dbd16ebaf907
child 14211 7286c187596d
permissions -rw-r--r--
new session HOL-SET-Protocol
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    10   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    11   (\<a>...\<z>), are now considered normal letters, and can therefore
    12   be used anywhere where an ASCII letter (a...zA...Z) has until
    13   now. COMPATIBILITY: This obviously changes the parsing of some
    14   terms, especially where a symbol has been used as a binder, say
    15   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    16   as an identifier.  Fix it by inserting a space around former
    17   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    18   existing theory and ML files.
    19 
    20 *** Isar ***
    21 
    22 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    23 
    24   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    25     locales are no longer forced to write Isar proof scripts.
    26     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    27     emulations.
    28   - INCOMPATIBILITY: names of variables to be instantiated may no
    29     longer be enclosed in quotes.  Instead, precede variable names containing
    30     dots with `?'.  This is consistent with the instantiation attribute
    31     "where".
    32 
    33 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    34   (Isar) contexts.
    35 
    36 *** HOL ***
    37 
    38 * 'specification' command added, allowing for definition by
    39 specification.
    40 
    41 * SET-Protocol: formalization and verification of the SET protocol suite;
    42 
    43 
    44 New in Isabelle2003 (May 2003)
    45 --------------------------------
    46 
    47 *** General ***
    48 
    49 * Provers/simplifier:
    50 
    51   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    52     Assumptions are now subject to complete mutual simplification,
    53     not just from left to right. The simplifier now preserves
    54     the order of assumptions.
    55 
    56     Potential INCOMPATIBILITY:
    57 
    58     -- simp sometimes diverges where the old version did
    59        not, e.g. invoking simp on the goal
    60 
    61         [| P (f x); y = x; f x = f y |] ==> Q
    62 
    63        now gives rise to the infinite reduction sequence
    64 
    65         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    66 
    67        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    68        kind of problem.
    69 
    70     -- Tactics combining classical reasoner and simplification (such as auto)
    71        are also affected by this change, because many of them rely on
    72        simp. They may sometimes diverge as well or yield a different numbers
    73        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    74        in case of problems. Sometimes subsequent calls to the classical
    75        reasoner will fail because a preceeding call to the simplifier too
    76        eagerly simplified the goal, e.g. deleted redundant premises.
    77 
    78   - The simplifier trace now shows the names of the applied rewrite rules
    79 
    80   - You can limit the number of recursive invocations of the simplifier
    81     during conditional rewriting (where the simplifie tries to solve the
    82     conditions before applying the rewrite rule):
    83     ML "simp_depth_limit := n"
    84     where n is an integer. Thus you can force termination where previously
    85     the simplifier would diverge.
    86 
    87   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
    88 
    89   - No longer aborts on failed congruence proof.  Instead, the
    90     congruence is ignored.
    91 
    92 * Pure: New generic framework for extracting programs from constructive
    93   proofs. See HOL/Extraction.thy for an example instantiation, as well
    94   as HOL/Extraction for some case studies.
    95 
    96 * Pure: The main goal of the proof state is no longer shown by default, only
    97 the subgoals. This behaviour is controlled by a new flag.
    98    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
    99 (ML: Proof.show_main_goal).
   100 
   101 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   102 rules whose conclusion matches subgoal 1:
   103       PG menu: Isabelle/Isar -> Show me -> matching rules
   104 The rules are ordered by how closely they match the subgoal.
   105 In particular, rules that solve a subgoal outright are displayed first
   106 (or rather last, the way they are printed).
   107 (ML: ProofGeneral.print_intros())
   108 
   109 * Pure: New flag trace_unify_fail causes unification to print
   110 diagnostic information (PG: in trace buffer) when it fails. This is
   111 useful for figuring out why single step proofs like rule, erule or
   112 assumption failed.
   113 
   114 * Pure: Locale specifications now produce predicate definitions
   115 according to the body of text (covering assumptions modulo local
   116 definitions); predicate "loc_axioms" covers newly introduced text,
   117 while "loc" is cumulative wrt. all included locale expressions; the
   118 latter view is presented only on export into the global theory
   119 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   120 on the old view without predicates;
   121 
   122 * Pure: predefined locales "var" and "struct" are useful for sharing
   123 parameters (as in CASL, for example); just specify something like
   124 ``var x + var y + struct M'' as import;
   125 
   126 * Pure: improved thms_containing: proper indexing of facts instead of
   127 raw theorems; check validity of results wrt. current name space;
   128 include local facts of proof configuration (also covers active
   129 locales), cover fixed variables in index; may use "_" in term
   130 specification; an optional limit for the number of printed facts may
   131 be given (the default is 40);
   132 
   133 * Pure: disallow duplicate fact bindings within new-style theory files
   134 (batch-mode only);
   135 
   136 * Provers: improved induct method: assumptions introduced by case
   137 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   138 the goal statement); "foo" still refers to all facts collectively;
   139 
   140 * Provers: the function blast.overloaded has been removed: all constants
   141 are regarded as potentially overloaded, which improves robustness in exchange
   142 for slight decrease in efficiency;
   143 
   144 * Provers/linorder: New generic prover for transitivity reasoning over
   145 linear orders.  Note: this prover is not efficient!
   146 
   147 * Isar: preview of problems to finish 'show' now produce an error
   148 rather than just a warning (in interactive mode);
   149 
   150 
   151 *** HOL ***
   152 
   153 * arith(_tac)
   154 
   155  - Produces a counter example if it cannot prove a goal.
   156    Note that the counter example may be spurious if the goal is not a formula
   157    of quantifier-free linear arithmetic.
   158    In ProofGeneral the counter example appears in the trace buffer.
   159 
   160  - Knows about div k and mod k where k is a numeral of type nat or int.
   161 
   162  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   163    linear arithmetic fails. This takes account of quantifiers and divisibility.
   164    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   165 
   166 * simp's arithmetic capabilities have been enhanced a bit: it now
   167 takes ~= in premises into account (by performing a case split);
   168 
   169 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   170 are distributed over a sum of terms;
   171 
   172 * New tactic "trans_tac" and method "trans" instantiate
   173 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   174 "<=", "<" and "="). 
   175 
   176 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   177 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   178 
   179 * 'typedef' command has new option "open" to suppress the set
   180 definition;
   181 
   182 * functions Min and Max on finite sets have been introduced (theory
   183 Finite_Set);
   184 
   185 * attribute [symmetric] now works for relations as well; it turns
   186 (x,y) : R^-1 into (y,x) : R, and vice versa;
   187 
   188 * induct over a !!-quantified statement (say !!x1..xn):
   189   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   190 
   191 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   192 %x. None. Warning: empty_def now refers to the previously hidden definition
   193 of the empty set.
   194 
   195 * Algebra: formalization of classical algebra.  Intended as base for
   196 any algebraic development in Isabelle.  Currently covers group theory
   197 (up to Sylow's theorem) and ring theory (Universal Property of
   198 Univariate Polynomials).  Contributions welcome;
   199 
   200 * GroupTheory: deleted, since its material has been moved to Algebra;
   201 
   202 * Complex: new directory of the complex numbers with numeric constants, 
   203 nonstandard complex numbers, and some complex analysis, standard and 
   204 nonstandard (Jacques Fleuriot);
   205 
   206 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   207 
   208 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   209 Fleuriot);
   210 
   211 * Real/HahnBanach: updated and adapted to locales;
   212 
   213 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   214 Gray and Kramer);
   215 
   216 * UNITY: added the Meier-Sanders theory of progress sets;
   217 
   218 * MicroJava: bytecode verifier and lightweight bytecode verifier
   219 as abstract algorithms, instantiated to the JVM;
   220 
   221 * Bali: Java source language formalization. Type system, operational
   222 semantics, axiomatic semantics. Supported language features:
   223 classes, interfaces, objects,virtual methods, static methods,
   224 static/instance fields, arrays, access modifiers, definite
   225 assignment, exceptions.
   226 
   227 
   228 *** ZF ***
   229 
   230 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   231 universe, etc.);
   232 
   233 * Main ZF: virtually all theories converted to new-style format;
   234 
   235 
   236 *** ML ***
   237 
   238 * Pure: Tactic.prove provides sane interface for internal proofs;
   239 omits the infamous "standard" operation, so this is more appropriate
   240 than prove_goalw_cterm in many situations (e.g. in simprocs);
   241 
   242 * Pure: improved error reporting of simprocs;
   243 
   244 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   245 up simprocs;
   246 
   247 
   248 *** Document preparation ***
   249 
   250 * uses \par instead of \\ for line breaks in theory text. This may
   251 shift some page breaks in large documents. To get the old behaviour
   252 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   253 
   254 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   255 other packages
   256 
   257 * \<euro> now needs package babel/greek instead of marvosym (which
   258 broke \Rightarrow)
   259 
   260 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   261 textcomp package)
   262 
   263 
   264 New in Isabelle2002 (March 2002)
   265 --------------------------------
   266 
   267 *** Document preparation ***
   268 
   269 * greatly simplified document preparation setup, including more
   270 graceful interpretation of isatool usedir -i/-d/-D options, and more
   271 instructive isatool mkdir; users should basically be able to get
   272 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   273 users may run a separate document processing stage manually like this:
   274 "isatool usedir -D output HOL Test && isatool document Test/output";
   275 
   276 * theory dependency graph may now be incorporated into documents;
   277 isatool usedir -g true will produce session_graph.eps/.pdf for use
   278 with \includegraphics of LaTeX;
   279 
   280 * proper spacing of consecutive markup elements, especially text
   281 blocks after section headings;
   282 
   283 * support bold style (for single symbols only), input syntax is like
   284 this: "\<^bold>\<alpha>" or "\<^bold>A";
   285 
   286 * \<bullet> is now output as bold \cdot by default, which looks much
   287 better in printed text;
   288 
   289 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   290 note that these symbols are currently unavailable in Proof General /
   291 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   292 
   293 * isatool latex no longer depends on changed TEXINPUTS, instead
   294 isatool document copies the Isabelle style files to the target
   295 location;
   296 
   297 
   298 *** Isar ***
   299 
   300 * Pure/Provers: improved proof by cases and induction;
   301   - 'case' command admits impromptu naming of parameters (such as
   302     "case (Suc n)");
   303   - 'induct' method divinates rule instantiation from the inductive
   304     claim; no longer requires excessive ?P bindings for proper
   305     instantiation of cases;
   306   - 'induct' method properly enumerates all possibilities of set/type
   307     rules; as a consequence facts may be also passed through *type*
   308     rules without further ado;
   309   - 'induct' method now derives symbolic cases from the *rulified*
   310     rule (before it used to rulify cases stemming from the internal
   311     atomized version); this means that the context of a non-atomic
   312     statement becomes is included in the hypothesis, avoiding the
   313     slightly cumbersome show "PROP ?case" form;
   314   - 'induct' may now use elim-style induction rules without chaining
   315     facts, using ``missing'' premises from the goal state; this allows
   316     rules stemming from inductive sets to be applied in unstructured
   317     scripts, while still benefitting from proper handling of non-atomic
   318     statements; NB: major inductive premises need to be put first, all
   319     the rest of the goal is passed through the induction;
   320   - 'induct' proper support for mutual induction involving non-atomic
   321     rule statements (uses the new concept of simultaneous goals, see
   322     below);
   323   - append all possible rule selections, but only use the first
   324     success (no backtracking);
   325   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   326   - undeclared rule case names default to numbers 1, 2, 3, ...;
   327   - added 'print_induct_rules' (covered by help item in recent Proof
   328     General versions);
   329   - moved induct/cases attributes to Pure, methods to Provers;
   330   - generic method setup instantiated for FOL and HOL;
   331 
   332 * Pure: support multiple simultaneous goal statements, for example
   333 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   334 meta-level mechanism, this acts as if several individual goals had
   335 been stated separately; in particular common proof methods need to be
   336 repeated in order to cover all claims; note that a single elimination
   337 step is *not* sufficient to establish the two conjunctions, so this
   338 fails:
   339 
   340   assume "A & B" then have A and B ..   (*".." fails*)
   341 
   342 better use "obtain" in situations as above; alternative refer to
   343 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   344 
   345 * Pure: proper integration with ``locales''; unlike the original
   346 version by Florian Kammüller, Isar locales package high-level proof
   347 contexts rather than raw logical ones (e.g. we admit to include
   348 attributes everywhere); operations on locales include merge and
   349 rename; support for implicit arguments (``structures''); simultaneous
   350 type-inference over imports and text; see also HOL/ex/Locales.thy for
   351 some examples;
   352 
   353 * Pure: the following commands have been ``localized'', supporting a
   354 target locale specification "(in name)": 'lemma', 'theorem',
   355 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   356 stored both within the locale and at the theory level (exported and
   357 qualified by the locale name);
   358 
   359 * Pure: theory goals may now be specified in ``long'' form, with
   360 ad-hoc contexts consisting of arbitrary locale elements. for example
   361 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   362 definitions may be given, too); the result is a meta-level rule with
   363 the context elements being discharged in the obvious way;
   364 
   365 * Pure: new proof command 'using' allows to augment currently used
   366 facts after a goal statement ('using' is syntactically analogous to
   367 'apply', but acts on the goal's facts only); this allows chained facts
   368 to be separated into parts given before and after a claim, as in
   369 ``from a and b have C using d and e <proof>'';
   370 
   371 * Pure: renamed "antecedent" case to "rule_context";
   372 
   373 * Pure: new 'judgment' command records explicit information about the
   374 object-logic embedding (used by several tools internally); no longer
   375 use hard-wired "Trueprop";
   376 
   377 * Pure: added 'corollary' command;
   378 
   379 * Pure: fixed 'token_translation' command;
   380 
   381 * Pure: removed obsolete 'exported' attribute;
   382 
   383 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   384 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   385 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   386 
   387 * Pure: method 'atomize' presents local goal premises as object-level
   388 statements (atomic meta-level propositions); setup controlled via
   389 rewrite rules declarations of 'atomize' attribute; example
   390 application: 'induct' method with proper rule statements in improper
   391 proof *scripts*;
   392 
   393 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   394 now consider the syntactic context of assumptions, giving a better
   395 chance to get type-inference of the arguments right (this is
   396 especially important for locales);
   397 
   398 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   399 mode;
   400 
   401 * Pure/obtain: the formal conclusion "thesis", being marked as
   402 ``internal'', may no longer be reference directly in the text;
   403 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   404 situations;
   405 
   406 * Pure: generic 'sym' attribute which declares a rule both as pure
   407 'elim?' and for the 'symmetric' operation;
   408 
   409 * Pure: marginal comments ``--'' may now occur just anywhere in the
   410 text; the fixed correlation with particular command syntax has been
   411 discontinued;
   412 
   413 * Pure: new method 'rules' is particularly well-suited for proof
   414 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   415 but often produces more compact proof terms with less detours;
   416 
   417 * Pure/Provers/classical: simplified integration with pure rule
   418 attributes and methods; the classical "intro?/elim?/dest?"
   419 declarations coincide with the pure ones; the "rule" method no longer
   420 includes classically swapped intros; "intro" and "elim" methods no
   421 longer pick rules from the context; also got rid of ML declarations
   422 AddXIs/AddXEs/AddXDs; all of this has some potential for
   423 INCOMPATIBILITY;
   424 
   425 * Provers/classical: attribute 'swapped' produces classical inversions
   426 of introduction rules;
   427 
   428 * Provers/simplifier: 'simplified' attribute may refer to explicit
   429 rules instead of full simplifier context; 'iff' attribute handles
   430 conditional rules;
   431 
   432 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   433 
   434 * HOL: 'recdef' now fails on unfinished automated proofs, use
   435 "(permissive)" option to recover old behavior;
   436 
   437 * HOL: 'inductive' no longer features separate (collective) attributes
   438 for 'intros' (was found too confusing);
   439 
   440 * HOL: properly declared induction rules less_induct and
   441 wf_induct_rule;
   442 
   443 
   444 *** HOL ***
   445 
   446 * HOL: moved over to sane numeral syntax; the new policy is as
   447 follows:
   448 
   449   - 0 and 1 are polymorphic constants, which are defined on any
   450   numeric type (nat, int, real etc.);
   451 
   452   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   453   binary representation internally;
   454 
   455   - type nat has special constructor Suc, and generally prefers Suc 0
   456   over 1::nat and Suc (Suc 0) over 2::nat;
   457 
   458 This change may cause significant problems of INCOMPATIBILITY; here
   459 are some hints on converting existing sources:
   460 
   461   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   462   entities, so expressions involving "-" (unary or binary minus) need
   463   to be spaced properly;
   464 
   465   - existing occurrences of "1" may need to be constraint "1::nat" or
   466   even replaced by Suc 0; similar for old "2";
   467 
   468   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   469 
   470   - remove all special provisions on numerals in proofs;
   471 
   472 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   473 representation (depends on bin_arith_simps in the default context);
   474 
   475 * HOL: symbolic syntax for x^2 (numeral 2);
   476 
   477 * HOL: the class of all HOL types is now called "type" rather than
   478 "term"; INCOMPATIBILITY, need to adapt references to this type class
   479 in axclass/classes, instance/arities, and (usually rare) occurrences
   480 in typings (of consts etc.); internally the class is called
   481 "HOL.type", ML programs should refer to HOLogic.typeS;
   482 
   483 * HOL/record package improvements:
   484   - new derived operations "fields" to build a partial record section,
   485     "extend" to promote a fixed record to a record scheme, and
   486     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   487     declared as simp by default;
   488   - shared operations ("more", "fields", etc.) now need to be always
   489     qualified) --- potential INCOMPATIBILITY;
   490   - removed "make_scheme" operations (use "make" with "extend") --
   491     INCOMPATIBILITY;
   492   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   493   - provides cases/induct rules for use with corresponding Isar
   494     methods (for concrete records, record schemes, concrete more
   495     parts, and schematic more parts -- in that order);
   496   - internal definitions directly based on a light-weight abstract
   497     theory of product types over typedef rather than datatype;
   498 
   499 * HOL: generic code generator for generating executable ML code from
   500 specifications; specific support for HOL constructs such as inductive
   501 datatypes and sets, as well as recursive functions; can be invoked
   502 via 'generate_code' theory section;
   503 
   504 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   505 
   506 * HOL: consolidated and renamed several theories.  In particular:
   507 	Ord.thy has been absorbed into HOL.thy
   508 	String.thy has been absorbed into List.thy
   509  
   510 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   511 (beware of argument permutation!);
   512 
   513 * HOL: linorder_less_split superseded by linorder_cases;
   514 
   515 * HOL/List: "nodups" renamed to "distinct";
   516 
   517 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   518 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   519   - Ex_def has changed, now need to use some_eq_ex
   520 
   521 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   522 in this (rare) case use:
   523 
   524   delSWrapper "split_all_tac"
   525   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   526 
   527 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   528 MAY FAIL;
   529 
   530 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   531 Isabelle's type classes, ^ on functions and relations has too general
   532 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   533 necessary to attach explicit type constraints;
   534 
   535 * HOL/Relation: the prefix name of the infix "O" has been changed from
   536 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   537 renamed accordingly (eg "compI" -> "rel_compI").
   538 
   539 * HOL: syntax translations now work properly with numerals and records
   540 expressions;
   541 
   542 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   543 of "lam" -- INCOMPATIBILITY;
   544 
   545 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   546 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   547 renamed "Product_Type.unit";
   548 
   549 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   550 
   551 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   552 the "cases" method);
   553 
   554 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   555 Florian Kammüller);
   556 
   557 * HOL/IMP: updated and converted to new-style theory format; several
   558 parts turned into readable document, with proper Isar proof texts and
   559 some explanations (by Gerwin Klein);
   560 
   561 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   562 
   563 * HOL-Hyperreal is now a logic image;
   564 
   565 
   566 *** HOLCF ***
   567 
   568 * Isar: consts/constdefs supports mixfix syntax for continuous
   569 operations;
   570 
   571 * Isar: domain package adapted to new-style theory format, e.g. see
   572 HOLCF/ex/Dnat.thy;
   573 
   574 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   575 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   576 lift.induct_tac, always use UU instead of Undef;
   577 
   578 * HOLCF/IMP: updated and converted to new-style theory;
   579 
   580 
   581 *** ZF ***
   582 
   583 * Isar: proper integration of logic-specific tools and packages,
   584 including theory commands '(co)inductive', '(co)datatype',
   585 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   586 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   587 
   588 * theory Main no longer includes AC; for the Axiom of Choice, base
   589 your theory on Main_ZFC;
   590 
   591 * the integer library now covers quotients and remainders, with many
   592 laws relating division to addition, multiplication, etc.;
   593 
   594 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   595 typeless version of the formalism;
   596 
   597 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   598 format;
   599 
   600 * ZF/Induct: new directory for examples of inductive definitions,
   601 including theory Multiset for multiset orderings; converted to
   602 new-style theory format;
   603 
   604 * ZF: many new theorems about lists, ordinals, etc.;
   605 
   606 
   607 *** General ***
   608 
   609 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   610 variable proof controls level of detail: 0 = no proofs (only oracle
   611 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   612 also ref manual for further ML interfaces;
   613 
   614 * Pure/axclass: removed obsolete ML interface
   615 goal_subclass/goal_arity;
   616 
   617 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   618 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   619 separate tokens, so expressions involving minus need to be spaced
   620 properly;
   621 
   622 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   623 rather than "infixl" or "infixr";
   624 
   625 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   626 sort constraint specifications in type inference; e.g. "x::_::foo"
   627 ensures that the type of "x" is of sort "foo" (but not necessarily a
   628 type variable);
   629 
   630 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   631 control output of nested => (types); the default behavior is
   632 "type_brackets";
   633 
   634 * Pure/syntax: builtin parse translation for "_constify" turns valued
   635 tokens into AST constants;
   636 
   637 * Pure/syntax: prefer later declarations of translations and print
   638 translation functions; potential INCOMPATIBILITY: need to reverse
   639 multiple declarations for same syntax element constant;
   640 
   641 * Pure/show_hyps reset by default (in accordance to existing Isar
   642 practice);
   643 
   644 * Provers/classical: renamed addaltern to addafter, addSaltern to
   645 addSafter;
   646 
   647 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   648 as well;
   649 
   650 * system: tested support for MacOS X; should be able to get Isabelle +
   651 Proof General to work in a plain Terminal after installing Poly/ML
   652 (e.g. from the Isabelle distribution area) and GNU bash alone
   653 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   654 support requires further installations, e.g. from
   655 http://fink.sourceforge.net/);
   656 
   657 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   658 
   659 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   660 of 40 MB), cf. ML_OPTIONS;
   661 
   662 * system: Proof General keywords specification is now part of the
   663 Isabelle distribution (see etc/isar-keywords.el);
   664 
   665 * system: support for persistent Proof General sessions (refrain from
   666 outdating all loaded theories on startup); user may create writable
   667 logic images like this: ``isabelle -q HOL Test'';
   668 
   669 * system: smart selection of Isabelle process versus Isabelle
   670 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   671 run both "isabelle" and "Isabelle" even if file names are badly
   672 damaged (executable inspects the case of the first letter of its own
   673 name); added separate "isabelle-process" and "isabelle-interface";
   674 
   675 * system: refrain from any attempt at filtering input streams; no
   676 longer support ``8bit'' encoding of old isabelle font, instead proper
   677 iso-latin characters may now be used; the related isatools
   678 "symbolinput" and "nonascii" have disappeared as well;
   679 
   680 * system: removed old "xterm" interface (the print modes "xterm" and
   681 "xterm_color" are still available for direct use in a suitable
   682 terminal);
   683 
   684 
   685 
   686 New in Isabelle99-2 (February 2001)
   687 -----------------------------------
   688 
   689 *** Overview of INCOMPATIBILITIES ***
   690 
   691 * HOL: please note that theories in the Library and elsewhere often use the
   692 new-style (Isar) format; to refer to their theorems in an ML script you must
   693 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   694 
   695 * HOL: inductive package no longer splits induction rule aggressively,
   696 but only as far as specified by the introductions given; the old
   697 format may be recovered via ML function complete_split_rule or attribute
   698 'split_rule (complete)';
   699 
   700 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   701 gfp_Tarski to gfp_unfold;
   702 
   703 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   704 
   705 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   706 relation); infix "^^" has been renamed "``"; infix "``" has been
   707 renamed "`"; "univalent" has been renamed "single_valued";
   708 
   709 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   710 operation;
   711 
   712 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   713 
   714 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   715 
   716 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   717 consequence, it is no longer monotonic wrt. the local goal context
   718 (which is now passed through the inductive cases);
   719 
   720 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   721 \<gg> to \<ggreater>;
   722 
   723 
   724 *** Document preparation ***
   725 
   726 * \isabellestyle{NAME} selects version of Isabelle output (currently
   727 available: are "it" for near math-mode best-style output, "sl" for
   728 slanted text style, and "tt" for plain type-writer; if no
   729 \isabellestyle command is given, output is according to slanted
   730 type-writer);
   731 
   732 * support sub/super scripts (for single symbols only), input syntax is
   733 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   734 
   735 * some more standard symbols; see Appendix A of the system manual for
   736 the complete list of symbols defined in isabellesym.sty;
   737 
   738 * improved isabelle style files; more abstract symbol implementation
   739 (should now use \isamath{...} and \isatext{...} in custom symbol
   740 definitions);
   741 
   742 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   743 state; Note that presentation of goal states does not conform to
   744 actual human-readable proof documents.  Please do not include goal
   745 states into document output unless you really know what you are doing!
   746 
   747 * proper indentation of antiquoted output with proportional LaTeX
   748 fonts;
   749 
   750 * no_document ML operator temporarily disables LaTeX document
   751 generation;
   752 
   753 * isatool unsymbolize tunes sources for plain ASCII communication;
   754 
   755 
   756 *** Isar ***
   757 
   758 * Pure: Isar now suffers initial goal statements to contain unbound
   759 schematic variables (this does not conform to actual readable proof
   760 documents, due to unpredictable outcome and non-compositional proof
   761 checking); users who know what they are doing may use schematic goals
   762 for Prolog-style synthesis of proven results;
   763 
   764 * Pure: assumption method (an implicit finishing) now handles actual
   765 rules as well;
   766 
   767 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   768 initial goal, declare "that" only as Pure intro (only for single
   769 steps); the "that" rule assumption may now be involved in implicit
   770 finishing, thus ".." becomes a feasible for trivial obtains;
   771 
   772 * Pure: default proof step now includes 'intro_classes'; thus trivial
   773 instance proofs may be performed by "..";
   774 
   775 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   776 statements as well;
   777 
   778 * Pure: more robust selection of calculational rules;
   779 
   780 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   781 rule (as well as the assumption rule);
   782 
   783 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   784 lemmas, using the graph browser tool;
   785 
   786 * Pure: predict failure of "show" in interactive mode;
   787 
   788 * Pure: 'thms_containing' now takes actual terms as arguments;
   789 
   790 * HOL: improved method 'induct' --- now handles non-atomic goals
   791 (potential INCOMPATIBILITY); tuned error handling;
   792 
   793 * HOL: cases and induct rules now provide explicit hints about the
   794 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   795 any remaining facts are inserted into the goal verbatim;
   796 
   797 * HOL: local contexts (aka cases) may now contain term bindings as
   798 well; the 'cases' and 'induct' methods new provide a ?case binding for
   799 the result to be shown in each case;
   800 
   801 * HOL: added 'recdef_tc' command;
   802 
   803 * isatool convert assists in eliminating legacy ML scripts;
   804 
   805 
   806 *** HOL ***
   807 
   808 * HOL/Library: a collection of generic theories to be used together
   809 with main HOL; the theory loader path already includes this directory
   810 by default; the following existing theories have been moved here:
   811 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   812 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   813 
   814 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   815 modelling and verification task performed in Isabelle/HOL +
   816 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   817 
   818 * HOL/Algebra: special summation operator SUM no longer exists, it has
   819 been replaced by setsum; infix 'assoc' now has priority 50 (like
   820 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   821 'domain', this makes the theory consistent with mathematical
   822 literature;
   823 
   824 * HOL basics: added overloaded operations "inverse" and "divide"
   825 (infix "/"), syntax for generic "abs" operation, generic summation
   826 operator \<Sum>;
   827 
   828 * HOL/typedef: simplified package, provide more useful rules (see also
   829 HOL/subset.thy);
   830 
   831 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   832 now expressed as a proper nested rule (old-style tactic scripts may
   833 require atomize_strip_tac to cope with non-atomic premises);
   834 
   835 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   836 to "split_conv" (old name still available for compatibility);
   837 
   838 * HOL: improved concrete syntax for strings (e.g. allows translation
   839 rules with string literals);
   840 
   841 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   842  and Fleuriot's mechanization of analysis, including the transcendental
   843  functions for the reals;
   844 
   845 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   846 
   847 
   848 *** CTT ***
   849 
   850 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   851 "lam" is displayed as TWO lambda-symbols
   852 
   853 * CTT: theory Main now available, containing everything (that is, Bool
   854 and Arith);
   855 
   856 
   857 *** General ***
   858 
   859 * Pure: the Simplifier has been implemented properly as a derived rule
   860 outside of the actual kernel (at last!); the overall performance
   861 penalty in practical applications is about 50%, while reliability of
   862 the Isabelle inference kernel has been greatly improved;
   863 
   864 * print modes "brackets" and "no_brackets" control output of nested =>
   865 (types) and ==> (props); the default behaviour is "brackets";
   866 
   867 * Provers: fast_tac (and friends) now handle actual object-logic rules
   868 as assumptions as well;
   869 
   870 * system: support Poly/ML 4.0;
   871 
   872 * system: isatool install handles KDE version 1 or 2;
   873 
   874 
   875 
   876 New in Isabelle99-1 (October 2000)
   877 ----------------------------------
   878 
   879 *** Overview of INCOMPATIBILITIES ***
   880 
   881 * HOL: simplification of natural numbers is much changed; to partly
   882 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   883 issue the following ML commands:
   884 
   885   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   886   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   887 
   888 * HOL: simplification no longer dives into case-expressions; this is
   889 controlled by "t.weak_case_cong" for each datatype t;
   890 
   891 * HOL: nat_less_induct renamed to less_induct;
   892 
   893 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   894 fixsome to patch .thy and .ML sources automatically;
   895 
   896   select_equality  -> some_equality
   897   select_eq_Ex     -> some_eq_ex
   898   selectI2EX       -> someI2_ex
   899   selectI2         -> someI2
   900   selectI          -> someI
   901   select1_equality -> some1_equality
   902   Eps_sym_eq       -> some_sym_eq_trivial
   903   Eps_eq           -> some_eq_trivial
   904 
   905 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   906 
   907 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   908 instead);
   909 
   910 * HOL: the recursion equations generated by 'recdef' are now called
   911 f.simps instead of f.rules;
   912 
   913 * HOL: qed_spec_mp now also handles bounded ALL as well;
   914 
   915 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   916 sometimes be needed;
   917 
   918 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   919 
   920 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   921 
   922 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   923 product is now "<*>" instead of "Times"; the lexicographic product is
   924 now "<*lex*>" instead of "**";
   925 
   926 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   927 of main HOL, but was unused); better use HOL's datatype package;
   928 
   929 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   930 the old syntax may be recovered as follows:
   931 
   932   syntax (symbols)
   933     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   934       (infixl "\\<oplus>" 100)
   935 
   936 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   937 
   938 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   939 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   940 internally;
   941 
   942 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   943 changed from A/r to A//r;
   944 
   945 * ZF: new treatment of arithmetic (nat & int) may break some old
   946 proofs;
   947 
   948 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   949 rulify -> rule_format, elimify -> elim_format, ...);
   950 
   951 * Isar/Provers: intro/elim/dest attributes changed; renamed
   952 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   953 should have to change intro!! to intro? only); replaced "delrule" by
   954 "rule del";
   955 
   956 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   957 
   958 * Provers: strengthened force_tac by using new first_best_tac;
   959 
   960 * LaTeX document preparation: several changes of isabelle.sty (see
   961 lib/texinputs);
   962 
   963 
   964 *** Document preparation ***
   965 
   966 * formal comments (text blocks etc.) in new-style theories may now
   967 contain antiquotations of thm/prop/term/typ/text to be presented
   968 according to latex print mode; concrete syntax is like this:
   969 @{term[show_types] "f(x) = a + x"};
   970 
   971 * isatool mkdir provides easy setup of Isabelle session directories,
   972 including proper document sources;
   973 
   974 * generated LaTeX sources are now deleted after successful run
   975 (isatool document -c); may retain a copy somewhere else via -D option
   976 of isatool usedir;
   977 
   978 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   979 style files, achieving self-contained LaTeX sources and simplifying
   980 LaTeX debugging;
   981 
   982 * old-style theories now produce (crude) LaTeX output as well;
   983 
   984 * browser info session directories are now self-contained (may be put
   985 on WWW server seperately); improved graphs of nested sessions; removed
   986 graph for 'all sessions';
   987 
   988 * several improvements in isabelle style files; \isabellestyle{it}
   989 produces fake math mode output; \isamarkupheader is now \section by
   990 default; see lib/texinputs/isabelle.sty etc.;
   991 
   992 
   993 *** Isar ***
   994 
   995 * Isar/Pure: local results and corresponding term bindings are now
   996 subject to Hindley-Milner polymorphism (similar to ML); this
   997 accommodates incremental type-inference very nicely;
   998 
   999 * Isar/Pure: new derived language element 'obtain' supports
  1000 generalized existence reasoning;
  1001 
  1002 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1003 support accumulation of results, without applying any rules yet;
  1004 useful to collect intermediate results without explicit name
  1005 references, and for use with transitivity rules with more than 2
  1006 premises;
  1007 
  1008 * Isar/Pure: scalable support for case-analysis type proofs: new
  1009 'case' language element refers to local contexts symbolically, as
  1010 produced by certain proof methods; internally, case names are attached
  1011 to theorems as "tags";
  1012 
  1013 * Isar/Pure: theory command 'hide' removes declarations from
  1014 class/type/const name spaces;
  1015 
  1016 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1017 indicate potential overloading;
  1018 
  1019 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1020 
  1021 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1022 "{a,b,c}" instead of {a,b,c};
  1023 
  1024 * Isar/Pure now provides its own version of intro/elim/dest
  1025 attributes; useful for building new logics, but beware of confusion
  1026 with the version in Provers/classical;
  1027 
  1028 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1029 case name 'antecedent';
  1030 
  1031 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1032 to the current context is now done automatically);
  1033 
  1034 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1035 for definining proof methods in ML;
  1036 
  1037 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1038 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1039 most cases, one should have to change intro!! to intro? only);
  1040 replaced "delrule" by "rule del";
  1041 
  1042 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1043 'symmetric' attribute (the latter supercedes [RS sym]);
  1044 
  1045 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1046 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1047 well (including splits);
  1048 
  1049 * Isar/Provers: Simplifier and Classical methods now support all kind
  1050 of modifiers used in the past, including 'cong', 'iff', etc.
  1051 
  1052 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1053 of Simplifier and Classical reasoner);
  1054 
  1055 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1056 now support named cases; major packages (inductive, datatype, primrec,
  1057 recdef) support case names and properly name parameters;
  1058 
  1059 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1060 monotonicity conditions are extracted to be proven at end of
  1061 calculations;
  1062 
  1063 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1064 method anyway;
  1065 
  1066 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1067 split_if split_if_asm; datatype package provides theorems foo.splits =
  1068 foo.split foo.split_asm for each datatype;
  1069 
  1070 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1071 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1072 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1073 use "(cases (simplified))" method in proper proof texts);
  1074 
  1075 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1076 
  1077 * Isar: names of theorems etc. may be natural numbers as well;
  1078 
  1079 * Isar: 'pr' command: optional arguments for goals_limit and
  1080 ProofContext.prems_limit; no longer prints theory contexts, but only
  1081 proof states;
  1082 
  1083 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1084 additional print modes to be specified; e.g. "pr(latex)" will print
  1085 proof state according to the Isabelle LaTeX style;
  1086 
  1087 * Isar: improved support for emulating tactic scripts, including proof
  1088 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1089 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1090 (for HOL datatypes);
  1091 
  1092 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1093 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1094 'proof method scripts' have to be in depth-first order;
  1095 
  1096 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1097 
  1098 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1099 should instead use individual commands for printing items
  1100 (print_commands, print_methods etc.);
  1101 
  1102 * Isar: added 'nothing' --- the empty list of theorems;
  1103 
  1104 
  1105 *** HOL ***
  1106 
  1107 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1108 corresponding virtual machine and a specification of its bytecode
  1109 verifier and a lightweight bytecode verifier, including proofs of
  1110 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1111 Cornelia Pusch (see also the homepage of project Bali at
  1112 http://isabelle.in.tum.de/Bali/);
  1113 
  1114 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1115 Clemens Ballarin;
  1116 
  1117 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1118 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1119 Rasmussen;
  1120 
  1121 * HOL/Lattice: fundamental concepts of lattice theory and order
  1122 structures, including duals, properties of bounds versus algebraic
  1123 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1124 Theorem for complete lattices etc.; may also serve as a demonstration
  1125 for abstract algebraic reasoning using axiomatic type classes, and
  1126 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1127 
  1128 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1129 von Oheimb;
  1130 
  1131 * HOL/IMPP: extension of IMP with local variables and mutually
  1132 recursive procedures, by David von Oheimb;
  1133 
  1134 * HOL/Lambda: converted into new-style theory and document;
  1135 
  1136 * HOL/ex/Multiquote: example of multiple nested quotations and
  1137 anti-quotations -- basically a generalized version of de-Bruijn
  1138 representation; very useful in avoiding lifting of operations;
  1139 
  1140 * HOL/record: added general record equality rule to simpset; fixed
  1141 select-update simplification procedure to handle extended records as
  1142 well; admit "r" as field name;
  1143 
  1144 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1145 other numeric types and also as the identity of groups, rings, etc.;
  1146 
  1147 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1148 Types nat and int belong to this axclass;
  1149 
  1150 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1151    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1152    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1153   two terms #m*u and #n*u are replaced by #(m+n)*u
  1154     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1155   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1156     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1157 
  1158 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1159 powerful prover for predicate logic but knows nothing of clasets; see
  1160 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1161 
  1162 * HOL: new version of "case_tac" subsumes both boolean case split and
  1163 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1164 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1165 
  1166 * HOL: simplification no longer dives into case-expressions: only the
  1167 selector expression is simplified, but not the remaining arms; to
  1168 enable full simplification of case-expressions for datatype t, you may
  1169 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1170 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1171 
  1172 * HOL/recdef: the recursion equations generated by 'recdef' for
  1173 function 'f' are now called f.simps instead of f.rules; if all
  1174 termination conditions are proved automatically, these simplification
  1175 rules are added to the simpset, as in primrec; rules may be named
  1176 individually as well, resulting in a separate list of theorems for
  1177 each equation;
  1178 
  1179 * HOL/While is a new theory that provides a while-combinator. It
  1180 permits the definition of tail-recursive functions without the
  1181 provision of a termination measure. The latter is necessary once the
  1182 invariant proof rule for while is applied.
  1183 
  1184 * HOL: new (overloaded) notation for the set of elements below/above
  1185 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1186 
  1187 * HOL: theorems impI, allI, ballI bound as "strip";
  1188 
  1189 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1190 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1191 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1192 
  1193 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1194 
  1195 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1196 main HOL, but was unused);
  1197 
  1198 * HOL: fewer consts declared as global (e.g. have to refer to
  1199 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1200 
  1201 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1202 in case of overlap with user translations (e.g. judgements over
  1203 tuples); (note that the underlying logical represenation is still
  1204 bogus);
  1205 
  1206 
  1207 *** ZF ***
  1208 
  1209 * ZF: simplification automatically cancels common terms in arithmetic
  1210 expressions over nat and int;
  1211 
  1212 * ZF: new treatment of nat to minimize type-checking: all operators
  1213 coerce their operands to a natural number using the function natify,
  1214 making the algebraic laws unconditional;
  1215 
  1216 * ZF: as above, for int: operators coerce their operands to an integer
  1217 using the function intify;
  1218 
  1219 * ZF: the integer library now contains many of the usual laws for the
  1220 orderings, including $<=, and monotonicity laws for $+ and $*;
  1221 
  1222 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1223 simplification;
  1224 
  1225 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1226 to the simplifier and classical reasoner simultaneously;
  1227 
  1228 
  1229 *** General ***
  1230 
  1231 * Provers: blast_tac now handles actual object-logic rules as
  1232 assumptions; note that auto_tac uses blast_tac internally as well;
  1233 
  1234 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1235 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1236 
  1237 * Provers: delrules now handles destruct rules as well (no longer need
  1238 explicit make_elim);
  1239 
  1240 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1241   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1242 use instead the strong form,
  1243   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1244 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1245 from destruct-rules;
  1246 
  1247 * Provers: Simplifier.easy_setup provides a fast path to basic
  1248 Simplifier setup for new object-logics;
  1249 
  1250 * Pure: AST translation rules no longer require constant head on LHS;
  1251 
  1252 * Pure: improved name spaces: ambiguous output is qualified; support
  1253 for hiding of names;
  1254 
  1255 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1256 XSYMBOL_HOME; no longer need to do manual configuration in most
  1257 situations;
  1258 
  1259 * system: compression of ML heaps images may now be controlled via -c
  1260 option of isabelle and isatool usedir (currently only observed by
  1261 Poly/ML);
  1262 
  1263 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1264 useful for remote X11);
  1265 
  1266 * system: provide TAGS file for Isabelle sources;
  1267 
  1268 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1269 order;
  1270 
  1271 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1272 timing flag supersedes proof_timing and Toplevel.trace;
  1273 
  1274 * ML: new combinators |>> and |>>> for incremental transformations
  1275 with secondary results (e.g. certain theory extensions):
  1276 
  1277 * ML: PureThy.add_defs gets additional argument to indicate potential
  1278 overloading (usually false);
  1279 
  1280 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1281 results;
  1282 
  1283 
  1284 
  1285 New in Isabelle99 (October 1999)
  1286 --------------------------------
  1287 
  1288 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1289 
  1290 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1291 are no longer simplified.  (This allows the simplifier to unfold recursive
  1292 functional programs.)  To restore the old behaviour, declare
  1293 
  1294     Delcongs [if_weak_cong];
  1295 
  1296 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1297 complement;
  1298 
  1299 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1300 
  1301 * HOL/datatype: mutual_induct_tac no longer exists --
  1302   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1303 
  1304 * HOL/typedef: fixed type inference for representing set; type
  1305 arguments now have to occur explicitly on the rhs as type constraints;
  1306 
  1307 * ZF: The con_defs part of an inductive definition may no longer refer
  1308 to constants declared in the same theory;
  1309 
  1310 * HOL, ZF: the function mk_cases, generated by the inductive
  1311 definition package, has lost an argument.  To simplify its result, it
  1312 uses the default simpset instead of a supplied list of theorems.
  1313 
  1314 * HOL/List: the constructors of type list are now Nil and Cons;
  1315 
  1316 * Simplifier: the type of the infix ML functions
  1317         setSSolver addSSolver setSolver addSolver
  1318 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1319 for packaging solvers. A solver is created via
  1320         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1321 where the string argument is only a comment.
  1322 
  1323 
  1324 *** Proof tools ***
  1325 
  1326 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1327 decision procedure for linear arithmetic. Currently it is used for
  1328 types `nat', `int', and `real' in HOL (see below); it can, should and
  1329 will be instantiated for other types and logics as well.
  1330 
  1331 * The simplifier now accepts rewrite rules with flexible heads, eg
  1332      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1333   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1334   matching.
  1335 
  1336 
  1337 *** General ***
  1338 
  1339 * New Isabelle/Isar subsystem provides an alternative to traditional
  1340 tactical theorem proving; together with the ProofGeneral/isar user
  1341 interface it offers an interactive environment for developing human
  1342 readable proof documents (Isar == Intelligible semi-automated
  1343 reasoning); for further information see isatool doc isar-ref,
  1344 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1345 
  1346 * improved and simplified presentation of theories: better HTML markup
  1347 (including colors), graph views in several sizes; isatool usedir now
  1348 provides a proper interface for user theories (via -P option); actual
  1349 document preparation based on (PDF)LaTeX is available as well (for
  1350 new-style theories only); see isatool doc system for more information;
  1351 
  1352 * native support for Proof General, both for classic Isabelle and
  1353 Isabelle/Isar;
  1354 
  1355 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1356 using the graph browser tool;
  1357 
  1358 * Isabelle manuals now also available as PDF;
  1359 
  1360 * theory loader rewritten from scratch (may not be fully
  1361 bug-compatible); old loadpath variable has been replaced by show_path,
  1362 add_path, del_path, reset_path functions; new operations such as
  1363 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1364 isatool doc ref);
  1365 
  1366 * improved isatool install: option -k creates KDE application icon,
  1367 option -p DIR installs standalone binaries;
  1368 
  1369 * added ML_PLATFORM setting (useful for cross-platform installations);
  1370 more robust handling of platform specific ML images for SML/NJ;
  1371 
  1372 * the settings environment is now statically scoped, i.e. it is never
  1373 created again in sub-processes invoked from isabelle, isatool, or
  1374 Isabelle;
  1375 
  1376 * path element specification '~~' refers to '$ISABELLE_HOME';
  1377 
  1378 * in locales, the "assumes" and "defines" parts may be omitted if
  1379 empty;
  1380 
  1381 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1382 long arrows);
  1383 
  1384 * new print_mode "HTML";
  1385 
  1386 * new flag show_tags controls display of tags of theorems (which are
  1387 basically just comments that may be attached by some tools);
  1388 
  1389 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1390 mode and goal output format:
  1391 
  1392 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1393 244c244
  1394 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1395 ---
  1396 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1397 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1398 181c181
  1399 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1400 ---
  1401 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1402 
  1403 * function bind_thms stores lists of theorems (cf. bind_thm);
  1404 
  1405 * new shorthand tactics ftac, eatac, datac, fatac;
  1406 
  1407 * qed (and friends) now accept "" as result name; in that case the
  1408 theorem is not stored, but proper checks and presentation of the
  1409 result still apply;
  1410 
  1411 * theorem database now also indexes constants "Trueprop", "all",
  1412 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1413 
  1414 
  1415 *** HOL ***
  1416 
  1417 ** HOL arithmetic **
  1418 
  1419 * There are now decision procedures for linear arithmetic over nat and
  1420 int:
  1421 
  1422 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1423 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1424 are treated as atomic; subformulae not involving type `nat' or `int'
  1425 are ignored; quantified subformulae are ignored unless they are
  1426 positive universal or negative existential. The tactic has to be
  1427 invoked by hand and can be a little bit slow. In particular, the
  1428 running time is exponential in the number of occurrences of `min' and
  1429 `max', and `-' on `nat'.
  1430 
  1431 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1432 (negated) (in)equalities among the premises and the conclusion into
  1433 account (i.e. no compound formulae) and does not know about `min' and
  1434 `max', and `-' on `nat'. It is fast and is used automatically by the
  1435 simplifier.
  1436 
  1437 NB: At the moment, these decision procedures do not cope with mixed
  1438 nat/int formulae where the two parts interact, such as `m < n ==>
  1439 int(m) < int(n)'.
  1440 
  1441 * HOL/Numeral provides a generic theory of numerals (encoded
  1442 efficiently as bit strings); setup for types nat/int/real is in place;
  1443 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1444 int, existing theories and proof scripts may require a few additional
  1445 type constraints;
  1446 
  1447 * integer division and remainder can now be performed on constant
  1448 arguments;
  1449 
  1450 * many properties of integer multiplication, division and remainder
  1451 are now available;
  1452 
  1453 * An interface to the Stanford Validity Checker (SVC) is available through the
  1454 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1455 are proved automatically.  SVC must be installed separately, and its results
  1456 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1457 invocation of the underlying oracle).  For SVC see
  1458   http://verify.stanford.edu/SVC
  1459 
  1460 * IsaMakefile: the HOL-Real target now builds an actual image;
  1461 
  1462 
  1463 ** HOL misc **
  1464 
  1465 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1466 (in Isabelle/Isar) -- by Gertrud Bauer;
  1467 
  1468 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1469 analysis for assembly languages with subtypes;
  1470 
  1471 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1472 -- avoids syntactic ambiguities and treats state, transition, and
  1473 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1474 changed syntax and (many) tactics;
  1475 
  1476 * HOL/inductive: Now also handles more general introduction rules such
  1477   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1478   theorems are now maintained within the theory (maintained via the
  1479   "mono" attribute);
  1480 
  1481 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1482   (using function types) such as
  1483 
  1484   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1485 
  1486 * HOL/record: record_simproc (part of the default simpset) takes care
  1487 of selectors applied to updated records; record_split_tac is no longer
  1488 part of the default claset; update_defs may now be removed from the
  1489 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1490 
  1491   claset_ref () := claset() addSWrapper record_split_wrapper;
  1492   Delsimprocs [record_simproc]
  1493 
  1494 * HOL/typedef: fixed type inference for representing set; type
  1495 arguments now have to occur explicitly on the rhs as type constraints;
  1496 
  1497 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1498 names rather than an ML expression;
  1499 
  1500 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1501 supplied later.  Program schemes can be defined, such as
  1502     "While B C s = (if B s then While B C (C s) else s)"
  1503 where the well-founded relation can be chosen after B and C have been given.
  1504 
  1505 * HOL/List: the constructors of type list are now Nil and Cons;
  1506 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1507 course, ML tools referring to List.list.op # etc. have to be adapted;
  1508 
  1509 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1510 disabled by default; run isabelle with option -m HOL to get back to
  1511 the original Gordon/HOL-style output;
  1512 
  1513 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1514 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1515 
  1516 * HOL basic syntax simplified (more orthogonal): all variants of
  1517 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1518 Eps operator is provided as well: "SOME x. P[x]";
  1519 
  1520 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1521 
  1522 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1523 thus available for user theories;
  1524 
  1525 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1526 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1527 time;
  1528 
  1529 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1530 several times and then mp;
  1531 
  1532 
  1533 *** LK ***
  1534 
  1535 * the notation <<...>> is now available as a notation for sequences of
  1536 formulas;
  1537 
  1538 * the simplifier is now installed
  1539 
  1540 * the axiom system has been generalized (thanks to Soren Heilmann)
  1541 
  1542 * the classical reasoner now has a default rule database
  1543 
  1544 
  1545 *** ZF ***
  1546 
  1547 * new primrec section allows primitive recursive functions to be given
  1548 directly (as in HOL) over datatypes and the natural numbers;
  1549 
  1550 * new tactics induct_tac and exhaust_tac for induction (or case
  1551 analysis) over datatypes and the natural numbers;
  1552 
  1553 * the datatype declaration of type T now defines the recursor T_rec;
  1554 
  1555 * simplification automatically does freeness reasoning for datatype
  1556 constructors;
  1557 
  1558 * automatic type-inference, with AddTCs command to insert new
  1559 type-checking rules;
  1560 
  1561 * datatype introduction rules are now added as Safe Introduction rules
  1562 to the claset;
  1563 
  1564 * the syntax "if P then x else y" is now available in addition to
  1565 if(P,x,y);
  1566 
  1567 
  1568 *** Internal programming interfaces ***
  1569 
  1570 * tuned simplifier trace output; new flag debug_simp;
  1571 
  1572 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1573 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1574 
  1575 * AxClass.axclass_tac lost the theory argument;
  1576 
  1577 * tuned current_goals_markers semantics: begin / end goal avoids
  1578 printing empty lines;
  1579 
  1580 * removed prs and prs_fn hook, which was broken because it did not
  1581 include \n in its semantics, forcing writeln to add one
  1582 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1583 string -> unit if you really want to output text without newline;
  1584 
  1585 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1586 plain output, interface builders may have to enable 'isabelle_font'
  1587 mode to get Isabelle font glyphs as before;
  1588 
  1589 * refined token_translation interface; INCOMPATIBILITY: output length
  1590 now of type real instead of int;
  1591 
  1592 * theory loader actions may be traced via new ThyInfo.add_hook
  1593 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1594 your own database of information attached to *whole* theories -- as
  1595 opposed to intra-theory data slots offered via TheoryDataFun;
  1596 
  1597 * proper handling of dangling sort hypotheses (at last!);
  1598 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1599 extra sort hypotheses that can be witnessed from the type signature;
  1600 the force_strip_shyps flag is gone, any remaining shyps are simply
  1601 left in the theorem (with a warning issued by strip_shyps_warning);
  1602 
  1603 
  1604 
  1605 New in Isabelle98-1 (October 1998)
  1606 ----------------------------------
  1607 
  1608 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1609 
  1610 * several changes of automated proof tools;
  1611 
  1612 * HOL: major changes to the inductive and datatype packages, including
  1613 some minor incompatibilities of theory syntax;
  1614 
  1615 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1616 called `inj_on';
  1617 
  1618 * HOL: removed duplicate thms in Arith:
  1619   less_imp_add_less  should be replaced by  trans_less_add1
  1620   le_imp_add_le      should be replaced by  trans_le_add1
  1621 
  1622 * HOL: unary minus is now overloaded (new type constraints may be
  1623 required);
  1624 
  1625 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1626 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1627 now taken as an integer constant.
  1628 
  1629 * Pure: ML function 'theory_of' renamed to 'theory';
  1630 
  1631 
  1632 *** Proof tools ***
  1633 
  1634 * Simplifier:
  1635   1. Asm_full_simp_tac is now more aggressive.
  1636      1. It will sometimes reorient premises if that increases their power to
  1637         simplify.
  1638      2. It does no longer proceed strictly from left to right but may also
  1639         rotate premises to achieve further simplification.
  1640      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1641      old Asm_full_simp_tac in that it does not rotate premises.
  1642   2. The simplifier now knows a little bit about nat-arithmetic.
  1643 
  1644 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1645 allows for selected deletion of wrappers, by introduction of names for
  1646 wrapper functionals.  This implies that addbefore, addSbefore,
  1647 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1648 and that adding two tactics with the same name overwrites the first
  1649 one (emitting a warning).
  1650   type wrapper = (int -> tactic) -> (int -> tactic)
  1651   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1652   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1653   delWrapper, delSWrapper: claset *  string            -> claset
  1654   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1655 
  1656 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1657 semantics; addbefore now affects only the unsafe part of step_tac
  1658 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1659 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1660 by Force_tac;
  1661 
  1662 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1663 compWrapper; added safe wrapper (and access functions for it);
  1664 
  1665 * HOL/split_all_tac is now much faster and fails if there is nothing
  1666 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1667 and the names of the automatically generated variables have changed.
  1668 split_all_tac has moved within claset() from unsafe wrappers to safe
  1669 wrappers, which means that !!-bound variables are split much more
  1670 aggressively, and safe_tac and clarify_tac now split such variables.
  1671 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1672 Note: the same holds for record_split_tac, which does the job of
  1673 split_all_tac for record fields.
  1674 
  1675 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1676 permanently to the default simpset using Addsplits just like
  1677 Addsimps. They can be removed via Delsplits just like
  1678 Delsimps. Lower-case versions are also available.
  1679 
  1680 * HOL/Simplifier: The rule split_if is now part of the default
  1681 simpset. This means that the simplifier will eliminate all occurrences
  1682 of if-then-else in the conclusion of a goal. To prevent this, you can
  1683 either remove split_if completely from the default simpset by
  1684 `Delsplits [split_if]' or remove it in a specific call of the
  1685 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1686 other case splitting rules to/from the default simpset: every datatype
  1687 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1688 t is the name of the datatype).
  1689 
  1690 * Classical reasoner / Simplifier combination: new force_tac (and
  1691 derivatives Force_tac, force) combines rewriting and classical
  1692 reasoning (and whatever other tools) similarly to auto_tac, but is
  1693 aimed to solve the given subgoal completely.
  1694 
  1695 
  1696 *** General ***
  1697 
  1698 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1699 and `goalw': the theory is no longer needed as an explicit argument -
  1700 the current theory context is used; assumptions are no longer returned
  1701 at the ML-level unless one of them starts with ==> or !!; it is
  1702 recommended to convert to these new commands using isatool fixgoal
  1703 (backup your sources first!);
  1704 
  1705 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1706 the current theory context, and 'theory' to lookup stored theories;
  1707 
  1708 * new theory section 'locale' for declaring constants, assumptions and
  1709 definitions that have local scope;
  1710 
  1711 * new theory section 'nonterminals' for purely syntactic types;
  1712 
  1713 * new theory section 'setup' for generic ML setup functions
  1714 (e.g. package initialization);
  1715 
  1716 * the distribution now includes Isabelle icons: see
  1717 lib/logo/isabelle-{small,tiny}.xpm;
  1718 
  1719 * isatool install - install binaries with absolute references to
  1720 ISABELLE_HOME/bin;
  1721 
  1722 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1723 
  1724 * print mode 'emacs' reserved for Isamode;
  1725 
  1726 * support multiple print (ast) translations per constant name;
  1727 
  1728 * theorems involving oracles are now printed with a suffixed [!];
  1729 
  1730 
  1731 *** HOL ***
  1732 
  1733 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1734 
  1735 * HOL/inductive package reorganized and improved: now supports mutual
  1736 definitions such as
  1737 
  1738   inductive EVEN ODD
  1739     intrs
  1740       null "0 : EVEN"
  1741       oddI "n : EVEN ==> Suc n : ODD"
  1742       evenI "n : ODD ==> Suc n : EVEN"
  1743 
  1744 new theorem list "elims" contains an elimination rule for each of the
  1745 recursive sets; inductive definitions now handle disjunctive premises
  1746 correctly (also ZF);
  1747 
  1748 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1749 "mutual_induct" no longer exists - the induction rule is always
  1750 contained in "induct";
  1751 
  1752 
  1753 * HOL/datatype package re-implemented and greatly improved: now
  1754 supports mutually recursive datatypes such as
  1755 
  1756   datatype
  1757     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1758             | SUM ('a aexp) ('a aexp)
  1759             | DIFF ('a aexp) ('a aexp)
  1760             | NUM 'a
  1761   and
  1762     'a bexp = LESS ('a aexp) ('a aexp)
  1763             | AND ('a bexp) ('a bexp)
  1764             | OR ('a bexp) ('a bexp)
  1765 
  1766 as well as indirectly recursive datatypes such as
  1767 
  1768   datatype
  1769     ('a, 'b) term = Var 'a
  1770                   | App 'b ((('a, 'b) term) list)
  1771 
  1772 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1773 induction on mutually / indirectly recursive datatypes.
  1774 
  1775 Primrec equations are now stored in theory and can be accessed via
  1776 <function_name>.simps.
  1777 
  1778 INCOMPATIBILITIES:
  1779 
  1780   - Theories using datatypes must now have theory Datatype as an
  1781     ancestor.
  1782   - The specific <typename>.induct_tac no longer exists - use the
  1783     generic induct_tac instead.
  1784   - natE has been renamed to nat.exhaust - use exhaust_tac
  1785     instead of res_inst_tac ... natE. Note that the variable
  1786     names in nat.exhaust differ from the names in natE, this
  1787     may cause some "fragile" proofs to fail.
  1788   - The theorems split_<typename>_case and split_<typename>_case_asm
  1789     have been renamed to <typename>.split and <typename>.split_asm.
  1790   - Since default sorts of type variables are now handled correctly,
  1791     some datatype definitions may have to be annotated with explicit
  1792     sort constraints.
  1793   - Primrec definitions no longer require function name and type
  1794     of recursive argument.
  1795 
  1796 Consider using isatool fixdatatype to adapt your theories and proof
  1797 scripts to the new package (backup your sources first!).
  1798 
  1799 
  1800 * HOL/record package: considerably improved implementation; now
  1801 includes concrete syntax for record types, terms, updates; theorems
  1802 for surjective pairing and splitting !!-bound record variables; proof
  1803 support is as follows:
  1804 
  1805   1) standard conversions (selectors or updates applied to record
  1806 constructor terms) are part of the standard simpset;
  1807 
  1808   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1809 made part of standard simpset and claset via addIffs;
  1810 
  1811   3) a tactic for record field splitting (record_split_tac) is part of
  1812 the standard claset (addSWrapper);
  1813 
  1814 To get a better idea about these rules you may retrieve them via
  1815 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1816 the name of your record type.
  1817 
  1818 The split tactic 3) conceptually simplifies by the following rule:
  1819 
  1820   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1821 
  1822 Thus any record variable that is bound by meta-all will automatically
  1823 blow up into some record constructor term, consequently the
  1824 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1825 solve record problems automatically.
  1826 
  1827 
  1828 * reorganized the main HOL image: HOL/Integ and String loaded by
  1829 default; theory Main includes everything;
  1830 
  1831 * automatic simplification of integer sums and comparisons, using cancellation;
  1832 
  1833 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1834 
  1835 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1836 
  1837 * many new identities for unions, intersections, set difference, etc.;
  1838 
  1839 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1840 called split_if, split_split, split_sum_case and split_nat_case (to go
  1841 with add/delsplits);
  1842 
  1843 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1844 (?x::unit) = (); this is made part of the default simpset, which COULD
  1845 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1846 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1847 unit_abs_eta_conv is added in order to counter the effect of
  1848 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1849 %u.f();
  1850 
  1851 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1852 makes more sense);
  1853 
  1854 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1855   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1856   disjointness reasoning but breaking a few old proofs.
  1857 
  1858 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1859 to 'converse' from 'inverse' (for compatibility with ZF and some
  1860 literature);
  1861 
  1862 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1863 the well-founded relation;
  1864 
  1865 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1866     Compl A.  The "Compl" syntax remains available as input syntax for this
  1867     release ONLY.
  1868 
  1869 * HOL/Update: new theory of function updates:
  1870     f(a:=b) == %x. if x=a then b else f x
  1871 may also be iterated as in f(a:=b,c:=d,...);
  1872 
  1873 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1874 
  1875 * HOL/List:
  1876   - new function list_update written xs[i:=v] that updates the i-th
  1877     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1878   - new function `upt' written [i..j(] which generates the list
  1879     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1880     bound write [i..j], which is a shorthand for [i..j+1(].
  1881   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1882 
  1883 * HOL/Arith:
  1884   - removed 'pred' (predecessor) function;
  1885   - generalized some theorems about n-1;
  1886   - many new laws about "div" and "mod";
  1887   - new laws about greatest common divisors (see theory ex/Primes);
  1888 
  1889 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1890 instead of "inverse";
  1891 
  1892 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1893   of the multiset ordering;
  1894 
  1895 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1896   (not included by default);
  1897 
  1898 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1899 
  1900 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1901   programs, i.e. different program variables may have different types.
  1902 
  1903 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1904   [previously, this check worked only if the rewrite rule was unconditional]
  1905   Now rew can involve either definitions or equalities (either == or =).
  1906 
  1907 
  1908 *** ZF ***
  1909 
  1910 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1911   only the theorems proved on ZF.ML;
  1912 
  1913 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1914   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1915   disjointness reasoning but breaking a few old proofs.
  1916 
  1917 * ZF/Update: new theory of function updates
  1918     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1919   may also be iterated as in f(a:=b,c:=d,...);
  1920 
  1921 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1922 
  1923 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1924   [previously, this check worked only if the rewrite rule was unconditional]
  1925   Now rew can involve either definitions or equalities (either == or =).
  1926 
  1927 * case_tac provided for compatibility with HOL
  1928     (like the old excluded_middle_tac, but with subgoals swapped)
  1929 
  1930 
  1931 *** Internal programming interfaces ***
  1932 
  1933 * Pure: several new basic modules made available for general use, see
  1934 also src/Pure/README;
  1935 
  1936 * improved the theory data mechanism to support encapsulation (data
  1937 kind name replaced by private Object.kind, acting as authorization
  1938 key); new type-safe user interface via functor TheoryDataFun; generic
  1939 print_data function becomes basically useless;
  1940 
  1941 * removed global_names compatibility flag -- all theory declarations
  1942 are qualified by default;
  1943 
  1944 * module Pure/Syntax now offers quote / antiquote translation
  1945 functions (useful for Hoare logic etc. with implicit dependencies);
  1946 see HOL/ex/Antiquote for an example use;
  1947 
  1948 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1949 cterm -> thm;
  1950 
  1951 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1952 subgoal;
  1953 
  1954 * Display.print_goals function moved to Locale.print_goals;
  1955 
  1956 * standard print function for goals supports current_goals_markers
  1957 variable for marking begin of proof, end of proof, start of goal; the
  1958 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1959 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1960 for example;
  1961 
  1962 
  1963 
  1964 New in Isabelle98 (January 1998)
  1965 --------------------------------
  1966 
  1967 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1968 
  1969 * changed lexical syntax of terms / types: dots made part of long
  1970 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1971 
  1972 * simpset (and claset) reference variable replaced by functions
  1973 simpset / simpset_ref;
  1974 
  1975 * no longer supports theory aliases (via merge) and non-trivial
  1976 implicit merge of thms' signatures;
  1977 
  1978 * most internal names of constants changed due to qualified names;
  1979 
  1980 * changed Pure/Sequence interface (see Pure/seq.ML);
  1981 
  1982 
  1983 *** General Changes ***
  1984 
  1985 * hierachically structured name spaces (for consts, types, axms, thms
  1986 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1987 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1988 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1989 long_names for fully qualified output names; NOTE: ML programs
  1990 (special tactics, packages etc.) referring to internal names may have
  1991 to be adapted to cope with fully qualified names; in case of severe
  1992 backward campatibility problems try setting 'global_names' at compile
  1993 time to have enrything declared within a flat name space; one may also
  1994 fine tune name declarations in theories via the 'global' and 'local'
  1995 section;
  1996 
  1997 * reimplemented the implicit simpset and claset using the new anytype
  1998 data filed in signatures; references simpset:simpset ref etc. are
  1999 replaced by functions simpset:unit->simpset and
  2000 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2001 to patch your ML files accordingly;
  2002 
  2003 * HTML output now includes theory graph data for display with Java
  2004 applet or isatool browser; data generated automatically via isatool
  2005 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2006 
  2007 * defs may now be conditional; improved rewrite_goals_tac to handle
  2008 conditional equations;
  2009 
  2010 * defs now admits additional type arguments, using TYPE('a) syntax;
  2011 
  2012 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2013 creates a new theory node; implicit merge of thms' signatures is
  2014 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2015 transfer:theory->thm->thm in (rare) cases;
  2016 
  2017 * improved handling of draft signatures / theories; draft thms (and
  2018 ctyps, cterms) are automatically promoted to real ones;
  2019 
  2020 * slightly changed interfaces for oracles: admit many per theory, named
  2021 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2022 
  2023 * print_goals: optional output of const types (set show_consts and
  2024 show_types);
  2025 
  2026 * improved output of warnings (###) and errors (***);
  2027 
  2028 * subgoal_tac displays a warning if the new subgoal has type variables;
  2029 
  2030 * removed old README and Makefiles;
  2031 
  2032 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2033 
  2034 * removed obsolete init_pps and init_database;
  2035 
  2036 * deleted the obsolete tactical STATE, which was declared by
  2037     fun STATE tacfun st = tacfun st st;
  2038 
  2039 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2040 (which abbreviates $HOME);
  2041 
  2042 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2043 use isatool fixseq to adapt your ML programs (this works for fully
  2044 qualified references to the Sequence structure only!);
  2045 
  2046 * use_thy no longer requires writable current directory; it always
  2047 reloads .ML *and* .thy file, if either one is out of date;
  2048 
  2049 
  2050 *** Classical Reasoner ***
  2051 
  2052 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2053 tactics that use classical reasoning to simplify a subgoal without
  2054 splitting it into several subgoals;
  2055 
  2056 * Safe_tac: like safe_tac but uses the default claset;
  2057 
  2058 
  2059 *** Simplifier ***
  2060 
  2061 * added simplification meta rules:
  2062     (asm_)(full_)simplify: simpset -> thm -> thm;
  2063 
  2064 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2065 logics (again);
  2066 
  2067 * added prems argument to simplification procedures;
  2068 
  2069 * HOL, FOL, ZF: added infix function `addsplits':
  2070   instead of `<simpset> setloop (split_tac <thms>)'
  2071   you can simply write `<simpset> addsplits <thms>'
  2072 
  2073 
  2074 *** Syntax ***
  2075 
  2076 * TYPE('a) syntax for type reflection terms;
  2077 
  2078 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2079 
  2080 * pretty printer: changed order of mixfix annotation preference (again!);
  2081 
  2082 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2083 
  2084 
  2085 *** HOL ***
  2086 
  2087 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2088   with `addloop' of the simplifier to faciliate case splitting in premises.
  2089 
  2090 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2091 
  2092 * HOL/Auth: new protocol proofs including some for the Internet
  2093   protocol TLS;
  2094 
  2095 * HOL/Map: new theory of `maps' a la VDM;
  2096 
  2097 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2098 cancelling out common nat summands from =, <, <= (in)equalities, or
  2099 differences; simplification procedures nat_cancel_factor for
  2100 cancelling common factor from =, <, <= (in)equalities over natural
  2101 sums; nat_cancel contains both kinds of procedures, it is installed by
  2102 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2103 
  2104 * HOL/simplifier: terms of the form
  2105   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2106   are rewritten to
  2107   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2108   and those of the form
  2109   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2110   are rewritten to
  2111   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2112 
  2113 * HOL/datatype
  2114   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2115 
  2116   P(t_case f1 ... fn x) =
  2117      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2118         ...
  2119        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2120      )
  2121 
  2122   and a theorem `split_t_case_asm' of the form
  2123 
  2124   P(t_case f1 ... fn x) =
  2125     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2126         ...
  2127        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2128      )
  2129   which can be added to a simpset via `addsplits'. The existing theorems
  2130   expand_list_case and expand_option_case have been renamed to
  2131   split_list_case and split_option_case.
  2132 
  2133 * HOL/Arithmetic:
  2134   - `pred n' is automatically converted to `n-1'.
  2135     Users are strongly encouraged not to use `pred' any longer,
  2136     because it will disappear altogether at some point.
  2137   - Users are strongly encouraged to write "0 < n" rather than
  2138     "n ~= 0". Theorems and proof tools have been modified towards this
  2139     `standard'.
  2140 
  2141 * HOL/Lists:
  2142   the function "set_of_list" has been renamed "set" (and its theorems too);
  2143   the function "nth" now takes its arguments in the reverse order and
  2144   has acquired the infix notation "!" as in "xs!n".
  2145 
  2146 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2147 
  2148 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2149   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2150 
  2151 * HOL/record: extensible records with schematic structural subtyping
  2152 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2153 still lacks various theorems and concrete record syntax;
  2154 
  2155 
  2156 *** HOLCF ***
  2157 
  2158 * removed "axioms" and "generated by" sections;
  2159 
  2160 * replaced "ops" section by extended "consts" section, which is capable of
  2161   handling the continuous function space "->" directly;
  2162 
  2163 * domain package:
  2164   . proves theorems immediately and stores them in the theory,
  2165   . creates hierachical name space,
  2166   . now uses normal mixfix annotations (instead of cinfix...),
  2167   . minor changes to some names and values (for consistency),
  2168   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2169   . separator between mutual domain defs: changed "," to "and",
  2170   . improved handling of sort constraints;  now they have to
  2171     appear on the left-hand side of the equations only;
  2172 
  2173 * fixed LAM <x,y,zs>.b syntax;
  2174 
  2175 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2176 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2177 
  2178 
  2179 *** FOL and ZF ***
  2180 
  2181 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2182   with `addloop' of the simplifier to faciliate case splitting in premises.
  2183 
  2184 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2185 in HOL, they strip ALL and --> from proved theorems;
  2186 
  2187 
  2188 
  2189 New in Isabelle94-8 (May 1997)
  2190 ------------------------------
  2191 
  2192 *** General Changes ***
  2193 
  2194 * new utilities to build / run / maintain Isabelle etc. (in parts
  2195 still somewhat experimental); old Makefiles etc. still functional;
  2196 
  2197 * new 'Isabelle System Manual';
  2198 
  2199 * INSTALL text, together with ./configure and ./build scripts;
  2200 
  2201 * reimplemented type inference for greater efficiency, better error
  2202 messages and clean internal interface;
  2203 
  2204 * prlim command for dealing with lots of subgoals (an easier way of
  2205 setting goals_limit);
  2206 
  2207 
  2208 *** Syntax ***
  2209 
  2210 * supports alternative (named) syntax tables (parser and pretty
  2211 printer); internal interface is provided by add_modesyntax(_i);
  2212 
  2213 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2214 be used in conjunction with the Isabelle symbol font; uses the
  2215 "symbols" syntax table;
  2216 
  2217 * added token_translation interface (may translate name tokens in
  2218 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2219 the current print_mode); IMPORTANT: user print translation functions
  2220 are responsible for marking newly introduced bounds
  2221 (Syntax.mark_boundT);
  2222 
  2223 * token translations for modes "xterm" and "xterm_color" that display
  2224 names in bold, underline etc. or colors (which requires a color
  2225 version of xterm);
  2226 
  2227 * infixes may now be declared with names independent of their syntax;
  2228 
  2229 * added typed_print_translation (like print_translation, but may
  2230 access type of constant);
  2231 
  2232 
  2233 *** Classical Reasoner ***
  2234 
  2235 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2236 some limitations.  Blast_tac...
  2237   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2238   + ignores elimination rules that don't have the correct format
  2239         (the conclusion MUST be a formula variable)
  2240   + ignores types, which can make HOL proofs fail
  2241   + rules must not require higher-order unification, e.g. apply_type in ZF
  2242     [message "Function Var's argument not a bound variable" relates to this]
  2243   + its proof strategy is more general but can actually be slower
  2244 
  2245 * substitution with equality assumptions no longer permutes other
  2246 assumptions;
  2247 
  2248 * minor changes in semantics of addafter (now called addaltern); renamed
  2249 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2250 (and access functions for it);
  2251 
  2252 * improved combination of classical reasoner and simplifier:
  2253   + functions for handling clasimpsets
  2254   + improvement of addss: now the simplifier is called _after_ the
  2255     safe steps.
  2256   + safe variant of addss called addSss: uses safe simplifications
  2257     _during_ the safe steps. It is more complete as it allows multiple
  2258     instantiations of unknowns (e.g. with slow_tac).
  2259 
  2260 *** Simplifier ***
  2261 
  2262 * added interface for simplification procedures (functions that
  2263 produce *proven* rewrite rules on the fly, depending on current
  2264 redex);
  2265 
  2266 * ordering on terms as parameter (used for ordered rewriting);
  2267 
  2268 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2269 
  2270 * the solver is now split into a safe and an unsafe part.
  2271 This should be invisible for the normal user, except that the
  2272 functions setsolver and addsolver have been renamed to setSolver and
  2273 addSolver; added safe_asm_full_simp_tac;
  2274 
  2275 
  2276 *** HOL ***
  2277 
  2278 * a generic induction tactic `induct_tac' which works for all datatypes and
  2279 also for type `nat';
  2280 
  2281 * a generic case distinction tactic `exhaust_tac' which works for all
  2282 datatypes and also for type `nat';
  2283 
  2284 * each datatype comes with a function `size';
  2285 
  2286 * patterns in case expressions allow tuple patterns as arguments to
  2287 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2288 
  2289 * primrec now also works with type nat;
  2290 
  2291 * recdef: a new declaration form, allows general recursive functions to be
  2292 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2293 
  2294 * the constant for negation has been renamed from "not" to "Not" to
  2295 harmonize with FOL, ZF, LK, etc.;
  2296 
  2297 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2298 infinite lists;
  2299 
  2300 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2301 
  2302 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2303 problems in commutative rings, using axiomatic type classes for + and *;
  2304 
  2305 * more examples in HOL/MiniML and HOL/Auth;
  2306 
  2307 * more default rewrite rules for quantifiers, union/intersection;
  2308 
  2309 * a new constant `arbitrary == @x.False';
  2310 
  2311 * HOLCF/IOA replaces old HOL/IOA;
  2312 
  2313 * HOLCF changes: derived all rules and arities
  2314   + axiomatic type classes instead of classes
  2315   + typedef instead of faking type definitions
  2316   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2317   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2318   + eliminated the types void, one, tr
  2319   + use unit lift and bool lift (with translations) instead of one and tr
  2320   + eliminated blift from Lift3.thy (use Def instead of blift)
  2321   all eliminated rules are derived as theorems --> no visible changes ;
  2322 
  2323 
  2324 *** ZF ***
  2325 
  2326 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2327 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2328 as ZF_cs addSIs [equalityI];
  2329 
  2330 
  2331 
  2332 New in Isabelle94-7 (November 96)
  2333 ---------------------------------
  2334 
  2335 * allowing negative levels (as offsets) in prlev and choplev;
  2336 
  2337 * super-linear speedup for large simplifications;
  2338 
  2339 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2340 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2341 FAIL); can suppress it using the command Delsimps (ex_simps @
  2342 all_simps); De Morgan laws are also now included, by default;
  2343 
  2344 * improved printing of ==>  :  ~:
  2345 
  2346 * new object-logic "Sequents" adds linear logic, while replacing LK
  2347 and Modal (thanks to Sara Kalvala);
  2348 
  2349 * HOL/Auth: correctness proofs for authentication protocols;
  2350 
  2351 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2352 examples on HOL/Auth);
  2353 
  2354 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2355 the rewriter and classical reasoner simultaneously;
  2356 
  2357 * function uresult no longer returns theorems in "standard" format;
  2358 regain previous version by: val uresult = standard o uresult;
  2359 
  2360 
  2361 
  2362 New in Isabelle94-6
  2363 -------------------
  2364 
  2365 * oracles -- these establish an interface between Isabelle and trusted
  2366 external reasoners, which may deliver results as theorems;
  2367 
  2368 * proof objects (in particular record all uses of oracles);
  2369 
  2370 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2371 
  2372 * "constdefs" section in theory files;
  2373 
  2374 * "primrec" section (HOL) no longer requires names;
  2375 
  2376 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2377 
  2378 
  2379 
  2380 New in Isabelle94-5
  2381 -------------------
  2382 
  2383 * reduced space requirements;
  2384 
  2385 * automatic HTML generation from theories;
  2386 
  2387 * theory files no longer require "..." (quotes) around most types;
  2388 
  2389 * new examples, including two proofs of the Church-Rosser theorem;
  2390 
  2391 * non-curried (1994) version of HOL is no longer distributed;
  2392 
  2393 
  2394 
  2395 New in Isabelle94-4
  2396 -------------------
  2397 
  2398 * greatly reduced space requirements;
  2399 
  2400 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2401 
  2402 * searchable theorem database (see the section "Retrieving theorems" on
  2403 page 8 of the Reference Manual);
  2404 
  2405 * new examples, including Grabczewski's monumental case study of the
  2406 Axiom of Choice;
  2407 
  2408 * The previous version of HOL renamed to Old_HOL;
  2409 
  2410 * The new version of HOL (previously called CHOL) uses a curried syntax
  2411 for functions.  Application looks like f a b instead of f(a,b);
  2412 
  2413 * Mutually recursive inductive definitions finally work in HOL;
  2414 
  2415 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2416 translates to the operator "split";
  2417 
  2418 
  2419 
  2420 New in Isabelle94-3
  2421 -------------------
  2422 
  2423 * new infix operator, addss, allowing the classical reasoner to
  2424 perform simplification at each step of its search.  Example:
  2425         fast_tac (cs addss ss)
  2426 
  2427 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2428 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2429 look like (a,b) instead of <a,b>;
  2430 
  2431 * PLEASE NOTE: CHOL will eventually replace HOL!
  2432 
  2433 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2434 It translates to the operator "split".  A new theory of integers is available;
  2435 
  2436 * In ZF, integer numerals now denote two's-complement binary integers.
  2437 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2438 
  2439 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2440 of the Axiom of Choice;
  2441 
  2442 
  2443 
  2444 New in Isabelle94-2
  2445 -------------------
  2446 
  2447 * Significantly faster resolution;
  2448 
  2449 * the different sections in a .thy file can now be mixed and repeated
  2450 freely;
  2451 
  2452 * Database of theorems for FOL, HOL and ZF.  New
  2453 commands including qed, qed_goal and bind_thm store theorems in the database.
  2454 
  2455 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2456 a given theory (thms_of), or find out what theory a theorem was proved in
  2457 (theory_of_thm);
  2458 
  2459 * Bugs fixed in the inductive definition and datatype packages;
  2460 
  2461 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2462 and HOL_dup_cs obsolete;
  2463 
  2464 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2465 have been removed;
  2466 
  2467 * Simpler definition of function space in ZF;
  2468 
  2469 * new results about cardinal and ordinal arithmetic in ZF;
  2470 
  2471 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2472 types;
  2473 
  2474 
  2475 $Id$