NEWS
author ballarin
Fri Aug 29 15:40:11 2003 +0200 (2003-08-29)
changeset 14175 dbd16ebaf907
parent 14173 a3690aeb79d4
child 14199 d3b8d972a488
permissions -rw-r--r--
Method rule_tac understands Isar contexts: documentation.
     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 
    42 New in Isabelle2003 (May 2003)
    43 --------------------------------
    44 
    45 *** General ***
    46 
    47 * Provers/simplifier:
    48 
    49   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    50     Assumptions are now subject to complete mutual simplification,
    51     not just from left to right. The simplifier now preserves
    52     the order of assumptions.
    53 
    54     Potential INCOMPATIBILITY:
    55 
    56     -- simp sometimes diverges where the old version did
    57        not, e.g. invoking simp on the goal
    58 
    59         [| P (f x); y = x; f x = f y |] ==> Q
    60 
    61        now gives rise to the infinite reduction sequence
    62 
    63         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    64 
    65        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    66        kind of problem.
    67 
    68     -- Tactics combining classical reasoner and simplification (such as auto)
    69        are also affected by this change, because many of them rely on
    70        simp. They may sometimes diverge as well or yield a different numbers
    71        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    72        in case of problems. Sometimes subsequent calls to the classical
    73        reasoner will fail because a preceeding call to the simplifier too
    74        eagerly simplified the goal, e.g. deleted redundant premises.
    75 
    76   - The simplifier trace now shows the names of the applied rewrite rules
    77 
    78   - You can limit the number of recursive invocations of the simplifier
    79     during conditional rewriting (where the simplifie tries to solve the
    80     conditions before applying the rewrite rule):
    81     ML "simp_depth_limit := n"
    82     where n is an integer. Thus you can force termination where previously
    83     the simplifier would diverge.
    84 
    85   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
    86 
    87   - No longer aborts on failed congruence proof.  Instead, the
    88     congruence is ignored.
    89 
    90 * Pure: New generic framework for extracting programs from constructive
    91   proofs. See HOL/Extraction.thy for an example instantiation, as well
    92   as HOL/Extraction for some case studies.
    93 
    94 * Pure: The main goal of the proof state is no longer shown by default, only
    95 the subgoals. This behaviour is controlled by a new flag.
    96    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
    97 (ML: Proof.show_main_goal).
    98 
    99 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   100 rules whose conclusion matches subgoal 1:
   101       PG menu: Isabelle/Isar -> Show me -> matching rules
   102 The rules are ordered by how closely they match the subgoal.
   103 In particular, rules that solve a subgoal outright are displayed first
   104 (or rather last, the way they are printed).
   105 (ML: ProofGeneral.print_intros())
   106 
   107 * Pure: New flag trace_unify_fail causes unification to print
   108 diagnostic information (PG: in trace buffer) when it fails. This is
   109 useful for figuring out why single step proofs like rule, erule or
   110 assumption failed.
   111 
   112 * Pure: Locale specifications now produce predicate definitions
   113 according to the body of text (covering assumptions modulo local
   114 definitions); predicate "loc_axioms" covers newly introduced text,
   115 while "loc" is cumulative wrt. all included locale expressions; the
   116 latter view is presented only on export into the global theory
   117 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   118 on the old view without predicates;
   119 
   120 * Pure: predefined locales "var" and "struct" are useful for sharing
   121 parameters (as in CASL, for example); just specify something like
   122 ``var x + var y + struct M'' as import;
   123 
   124 * Pure: improved thms_containing: proper indexing of facts instead of
   125 raw theorems; check validity of results wrt. current name space;
   126 include local facts of proof configuration (also covers active
   127 locales), cover fixed variables in index; may use "_" in term
   128 specification; an optional limit for the number of printed facts may
   129 be given (the default is 40);
   130 
   131 * Pure: disallow duplicate fact bindings within new-style theory files
   132 (batch-mode only);
   133 
   134 * Provers: improved induct method: assumptions introduced by case
   135 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   136 the goal statement); "foo" still refers to all facts collectively;
   137 
   138 * Provers: the function blast.overloaded has been removed: all constants
   139 are regarded as potentially overloaded, which improves robustness in exchange
   140 for slight decrease in efficiency;
   141 
   142 * Provers/linorder: New generic prover for transitivity reasoning over
   143 linear orders.  Note: this prover is not efficient!
   144 
   145 * Isar: preview of problems to finish 'show' now produce an error
   146 rather than just a warning (in interactive mode);
   147 
   148 
   149 *** HOL ***
   150 
   151 * arith(_tac)
   152 
   153  - Produces a counter example if it cannot prove a goal.
   154    Note that the counter example may be spurious if the goal is not a formula
   155    of quantifier-free linear arithmetic.
   156    In ProofGeneral the counter example appears in the trace buffer.
   157 
   158  - Knows about div k and mod k where k is a numeral of type nat or int.
   159 
   160  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   161    linear arithmetic fails. This takes account of quantifiers and divisibility.
   162    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   163 
   164 * simp's arithmetic capabilities have been enhanced a bit: it now
   165 takes ~= in premises into account (by performing a case split);
   166 
   167 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   168 are distributed over a sum of terms;
   169 
   170 * New tactic "trans_tac" and method "trans" instantiate
   171 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   172 "<=", "<" and "="). 
   173 
   174 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   175 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   176 
   177 * 'typedef' command has new option "open" to suppress the set
   178 definition;
   179 
   180 * functions Min and Max on finite sets have been introduced (theory
   181 Finite_Set);
   182 
   183 * attribute [symmetric] now works for relations as well; it turns
   184 (x,y) : R^-1 into (y,x) : R, and vice versa;
   185 
   186 * induct over a !!-quantified statement (say !!x1..xn):
   187   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   188 
   189 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   190 %x. None. Warning: empty_def now refers to the previously hidden definition
   191 of the empty set.
   192 
   193 * Algebra: formalization of classical algebra.  Intended as base for
   194 any algebraic development in Isabelle.  Currently covers group theory
   195 (up to Sylow's theorem) and ring theory (Universal Property of
   196 Univariate Polynomials).  Contributions welcome;
   197 
   198 * GroupTheory: deleted, since its material has been moved to Algebra;
   199 
   200 * Complex: new directory of the complex numbers with numeric constants, 
   201 nonstandard complex numbers, and some complex analysis, standard and 
   202 nonstandard (Jacques Fleuriot);
   203 
   204 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   205 
   206 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   207 Fleuriot);
   208 
   209 * Real/HahnBanach: updated and adapted to locales;
   210 
   211 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   212 Gray and Kramer);
   213 
   214 * UNITY: added the Meier-Sanders theory of progress sets;
   215 
   216 * MicroJava: bytecode verifier and lightweight bytecode verifier
   217 as abstract algorithms, instantiated to the JVM;
   218 
   219 * Bali: Java source language formalization. Type system, operational
   220 semantics, axiomatic semantics. Supported language features:
   221 classes, interfaces, objects,virtual methods, static methods,
   222 static/instance fields, arrays, access modifiers, definite
   223 assignment, exceptions.
   224 
   225 
   226 *** ZF ***
   227 
   228 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   229 universe, etc.);
   230 
   231 * Main ZF: virtually all theories converted to new-style format;
   232 
   233 
   234 *** ML ***
   235 
   236 * Pure: Tactic.prove provides sane interface for internal proofs;
   237 omits the infamous "standard" operation, so this is more appropriate
   238 than prove_goalw_cterm in many situations (e.g. in simprocs);
   239 
   240 * Pure: improved error reporting of simprocs;
   241 
   242 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   243 up simprocs;
   244 
   245 
   246 *** Document preparation ***
   247 
   248 * uses \par instead of \\ for line breaks in theory text. This may
   249 shift some page breaks in large documents. To get the old behaviour
   250 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   251 
   252 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   253 other packages
   254 
   255 * \<euro> now needs package babel/greek instead of marvosym (which
   256 broke \Rightarrow)
   257 
   258 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   259 textcomp package)
   260 
   261 
   262 New in Isabelle2002 (March 2002)
   263 --------------------------------
   264 
   265 *** Document preparation ***
   266 
   267 * greatly simplified document preparation setup, including more
   268 graceful interpretation of isatool usedir -i/-d/-D options, and more
   269 instructive isatool mkdir; users should basically be able to get
   270 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   271 users may run a separate document processing stage manually like this:
   272 "isatool usedir -D output HOL Test && isatool document Test/output";
   273 
   274 * theory dependency graph may now be incorporated into documents;
   275 isatool usedir -g true will produce session_graph.eps/.pdf for use
   276 with \includegraphics of LaTeX;
   277 
   278 * proper spacing of consecutive markup elements, especially text
   279 blocks after section headings;
   280 
   281 * support bold style (for single symbols only), input syntax is like
   282 this: "\<^bold>\<alpha>" or "\<^bold>A";
   283 
   284 * \<bullet> is now output as bold \cdot by default, which looks much
   285 better in printed text;
   286 
   287 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   288 note that these symbols are currently unavailable in Proof General /
   289 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   290 
   291 * isatool latex no longer depends on changed TEXINPUTS, instead
   292 isatool document copies the Isabelle style files to the target
   293 location;
   294 
   295 
   296 *** Isar ***
   297 
   298 * Pure/Provers: improved proof by cases and induction;
   299   - 'case' command admits impromptu naming of parameters (such as
   300     "case (Suc n)");
   301   - 'induct' method divinates rule instantiation from the inductive
   302     claim; no longer requires excessive ?P bindings for proper
   303     instantiation of cases;
   304   - 'induct' method properly enumerates all possibilities of set/type
   305     rules; as a consequence facts may be also passed through *type*
   306     rules without further ado;
   307   - 'induct' method now derives symbolic cases from the *rulified*
   308     rule (before it used to rulify cases stemming from the internal
   309     atomized version); this means that the context of a non-atomic
   310     statement becomes is included in the hypothesis, avoiding the
   311     slightly cumbersome show "PROP ?case" form;
   312   - 'induct' may now use elim-style induction rules without chaining
   313     facts, using ``missing'' premises from the goal state; this allows
   314     rules stemming from inductive sets to be applied in unstructured
   315     scripts, while still benefitting from proper handling of non-atomic
   316     statements; NB: major inductive premises need to be put first, all
   317     the rest of the goal is passed through the induction;
   318   - 'induct' proper support for mutual induction involving non-atomic
   319     rule statements (uses the new concept of simultaneous goals, see
   320     below);
   321   - append all possible rule selections, but only use the first
   322     success (no backtracking);
   323   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   324   - undeclared rule case names default to numbers 1, 2, 3, ...;
   325   - added 'print_induct_rules' (covered by help item in recent Proof
   326     General versions);
   327   - moved induct/cases attributes to Pure, methods to Provers;
   328   - generic method setup instantiated for FOL and HOL;
   329 
   330 * Pure: support multiple simultaneous goal statements, for example
   331 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   332 meta-level mechanism, this acts as if several individual goals had
   333 been stated separately; in particular common proof methods need to be
   334 repeated in order to cover all claims; note that a single elimination
   335 step is *not* sufficient to establish the two conjunctions, so this
   336 fails:
   337 
   338   assume "A & B" then have A and B ..   (*".." fails*)
   339 
   340 better use "obtain" in situations as above; alternative refer to
   341 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   342 
   343 * Pure: proper integration with ``locales''; unlike the original
   344 version by Florian Kammüller, Isar locales package high-level proof
   345 contexts rather than raw logical ones (e.g. we admit to include
   346 attributes everywhere); operations on locales include merge and
   347 rename; support for implicit arguments (``structures''); simultaneous
   348 type-inference over imports and text; see also HOL/ex/Locales.thy for
   349 some examples;
   350 
   351 * Pure: the following commands have been ``localized'', supporting a
   352 target locale specification "(in name)": 'lemma', 'theorem',
   353 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   354 stored both within the locale and at the theory level (exported and
   355 qualified by the locale name);
   356 
   357 * Pure: theory goals may now be specified in ``long'' form, with
   358 ad-hoc contexts consisting of arbitrary locale elements. for example
   359 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   360 definitions may be given, too); the result is a meta-level rule with
   361 the context elements being discharged in the obvious way;
   362 
   363 * Pure: new proof command 'using' allows to augment currently used
   364 facts after a goal statement ('using' is syntactically analogous to
   365 'apply', but acts on the goal's facts only); this allows chained facts
   366 to be separated into parts given before and after a claim, as in
   367 ``from a and b have C using d and e <proof>'';
   368 
   369 * Pure: renamed "antecedent" case to "rule_context";
   370 
   371 * Pure: new 'judgment' command records explicit information about the
   372 object-logic embedding (used by several tools internally); no longer
   373 use hard-wired "Trueprop";
   374 
   375 * Pure: added 'corollary' command;
   376 
   377 * Pure: fixed 'token_translation' command;
   378 
   379 * Pure: removed obsolete 'exported' attribute;
   380 
   381 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   382 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   383 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   384 
   385 * Pure: method 'atomize' presents local goal premises as object-level
   386 statements (atomic meta-level propositions); setup controlled via
   387 rewrite rules declarations of 'atomize' attribute; example
   388 application: 'induct' method with proper rule statements in improper
   389 proof *scripts*;
   390 
   391 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   392 now consider the syntactic context of assumptions, giving a better
   393 chance to get type-inference of the arguments right (this is
   394 especially important for locales);
   395 
   396 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   397 mode;
   398 
   399 * Pure/obtain: the formal conclusion "thesis", being marked as
   400 ``internal'', may no longer be reference directly in the text;
   401 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   402 situations;
   403 
   404 * Pure: generic 'sym' attribute which declares a rule both as pure
   405 'elim?' and for the 'symmetric' operation;
   406 
   407 * Pure: marginal comments ``--'' may now occur just anywhere in the
   408 text; the fixed correlation with particular command syntax has been
   409 discontinued;
   410 
   411 * Pure: new method 'rules' is particularly well-suited for proof
   412 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   413 but often produces more compact proof terms with less detours;
   414 
   415 * Pure/Provers/classical: simplified integration with pure rule
   416 attributes and methods; the classical "intro?/elim?/dest?"
   417 declarations coincide with the pure ones; the "rule" method no longer
   418 includes classically swapped intros; "intro" and "elim" methods no
   419 longer pick rules from the context; also got rid of ML declarations
   420 AddXIs/AddXEs/AddXDs; all of this has some potential for
   421 INCOMPATIBILITY;
   422 
   423 * Provers/classical: attribute 'swapped' produces classical inversions
   424 of introduction rules;
   425 
   426 * Provers/simplifier: 'simplified' attribute may refer to explicit
   427 rules instead of full simplifier context; 'iff' attribute handles
   428 conditional rules;
   429 
   430 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   431 
   432 * HOL: 'recdef' now fails on unfinished automated proofs, use
   433 "(permissive)" option to recover old behavior;
   434 
   435 * HOL: 'inductive' no longer features separate (collective) attributes
   436 for 'intros' (was found too confusing);
   437 
   438 * HOL: properly declared induction rules less_induct and
   439 wf_induct_rule;
   440 
   441 
   442 *** HOL ***
   443 
   444 * HOL: moved over to sane numeral syntax; the new policy is as
   445 follows:
   446 
   447   - 0 and 1 are polymorphic constants, which are defined on any
   448   numeric type (nat, int, real etc.);
   449 
   450   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   451   binary representation internally;
   452 
   453   - type nat has special constructor Suc, and generally prefers Suc 0
   454   over 1::nat and Suc (Suc 0) over 2::nat;
   455 
   456 This change may cause significant problems of INCOMPATIBILITY; here
   457 are some hints on converting existing sources:
   458 
   459   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   460   entities, so expressions involving "-" (unary or binary minus) need
   461   to be spaced properly;
   462 
   463   - existing occurrences of "1" may need to be constraint "1::nat" or
   464   even replaced by Suc 0; similar for old "2";
   465 
   466   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   467 
   468   - remove all special provisions on numerals in proofs;
   469 
   470 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   471 representation (depends on bin_arith_simps in the default context);
   472 
   473 * HOL: symbolic syntax for x^2 (numeral 2);
   474 
   475 * HOL: the class of all HOL types is now called "type" rather than
   476 "term"; INCOMPATIBILITY, need to adapt references to this type class
   477 in axclass/classes, instance/arities, and (usually rare) occurrences
   478 in typings (of consts etc.); internally the class is called
   479 "HOL.type", ML programs should refer to HOLogic.typeS;
   480 
   481 * HOL/record package improvements:
   482   - new derived operations "fields" to build a partial record section,
   483     "extend" to promote a fixed record to a record scheme, and
   484     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   485     declared as simp by default;
   486   - shared operations ("more", "fields", etc.) now need to be always
   487     qualified) --- potential INCOMPATIBILITY;
   488   - removed "make_scheme" operations (use "make" with "extend") --
   489     INCOMPATIBILITY;
   490   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   491   - provides cases/induct rules for use with corresponding Isar
   492     methods (for concrete records, record schemes, concrete more
   493     parts, and schematic more parts -- in that order);
   494   - internal definitions directly based on a light-weight abstract
   495     theory of product types over typedef rather than datatype;
   496 
   497 * HOL: generic code generator for generating executable ML code from
   498 specifications; specific support for HOL constructs such as inductive
   499 datatypes and sets, as well as recursive functions; can be invoked
   500 via 'generate_code' theory section;
   501 
   502 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   503 
   504 * HOL: consolidated and renamed several theories.  In particular:
   505 	Ord.thy has been absorbed into HOL.thy
   506 	String.thy has been absorbed into List.thy
   507  
   508 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   509 (beware of argument permutation!);
   510 
   511 * HOL: linorder_less_split superseded by linorder_cases;
   512 
   513 * HOL/List: "nodups" renamed to "distinct";
   514 
   515 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   516 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   517   - Ex_def has changed, now need to use some_eq_ex
   518 
   519 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   520 in this (rare) case use:
   521 
   522   delSWrapper "split_all_tac"
   523   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   524 
   525 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   526 MAY FAIL;
   527 
   528 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   529 Isabelle's type classes, ^ on functions and relations has too general
   530 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   531 necessary to attach explicit type constraints;
   532 
   533 * HOL/Relation: the prefix name of the infix "O" has been changed from
   534 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   535 renamed accordingly (eg "compI" -> "rel_compI").
   536 
   537 * HOL: syntax translations now work properly with numerals and records
   538 expressions;
   539 
   540 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   541 of "lam" -- INCOMPATIBILITY;
   542 
   543 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   544 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   545 renamed "Product_Type.unit";
   546 
   547 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   548 
   549 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   550 the "cases" method);
   551 
   552 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   553 Florian Kammüller);
   554 
   555 * HOL/IMP: updated and converted to new-style theory format; several
   556 parts turned into readable document, with proper Isar proof texts and
   557 some explanations (by Gerwin Klein);
   558 
   559 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   560 
   561 * HOL-Hyperreal is now a logic image;
   562 
   563 
   564 *** HOLCF ***
   565 
   566 * Isar: consts/constdefs supports mixfix syntax for continuous
   567 operations;
   568 
   569 * Isar: domain package adapted to new-style theory format, e.g. see
   570 HOLCF/ex/Dnat.thy;
   571 
   572 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   573 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   574 lift.induct_tac, always use UU instead of Undef;
   575 
   576 * HOLCF/IMP: updated and converted to new-style theory;
   577 
   578 
   579 *** ZF ***
   580 
   581 * Isar: proper integration of logic-specific tools and packages,
   582 including theory commands '(co)inductive', '(co)datatype',
   583 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   584 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   585 
   586 * theory Main no longer includes AC; for the Axiom of Choice, base
   587 your theory on Main_ZFC;
   588 
   589 * the integer library now covers quotients and remainders, with many
   590 laws relating division to addition, multiplication, etc.;
   591 
   592 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   593 typeless version of the formalism;
   594 
   595 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   596 format;
   597 
   598 * ZF/Induct: new directory for examples of inductive definitions,
   599 including theory Multiset for multiset orderings; converted to
   600 new-style theory format;
   601 
   602 * ZF: many new theorems about lists, ordinals, etc.;
   603 
   604 
   605 *** General ***
   606 
   607 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   608 variable proof controls level of detail: 0 = no proofs (only oracle
   609 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   610 also ref manual for further ML interfaces;
   611 
   612 * Pure/axclass: removed obsolete ML interface
   613 goal_subclass/goal_arity;
   614 
   615 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   616 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   617 separate tokens, so expressions involving minus need to be spaced
   618 properly;
   619 
   620 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   621 rather than "infixl" or "infixr";
   622 
   623 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   624 sort constraint specifications in type inference; e.g. "x::_::foo"
   625 ensures that the type of "x" is of sort "foo" (but not necessarily a
   626 type variable);
   627 
   628 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   629 control output of nested => (types); the default behavior is
   630 "type_brackets";
   631 
   632 * Pure/syntax: builtin parse translation for "_constify" turns valued
   633 tokens into AST constants;
   634 
   635 * Pure/syntax: prefer later declarations of translations and print
   636 translation functions; potential INCOMPATIBILITY: need to reverse
   637 multiple declarations for same syntax element constant;
   638 
   639 * Pure/show_hyps reset by default (in accordance to existing Isar
   640 practice);
   641 
   642 * Provers/classical: renamed addaltern to addafter, addSaltern to
   643 addSafter;
   644 
   645 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   646 as well;
   647 
   648 * system: tested support for MacOS X; should be able to get Isabelle +
   649 Proof General to work in a plain Terminal after installing Poly/ML
   650 (e.g. from the Isabelle distribution area) and GNU bash alone
   651 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   652 support requires further installations, e.g. from
   653 http://fink.sourceforge.net/);
   654 
   655 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   656 
   657 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   658 of 40 MB), cf. ML_OPTIONS;
   659 
   660 * system: Proof General keywords specification is now part of the
   661 Isabelle distribution (see etc/isar-keywords.el);
   662 
   663 * system: support for persistent Proof General sessions (refrain from
   664 outdating all loaded theories on startup); user may create writable
   665 logic images like this: ``isabelle -q HOL Test'';
   666 
   667 * system: smart selection of Isabelle process versus Isabelle
   668 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   669 run both "isabelle" and "Isabelle" even if file names are badly
   670 damaged (executable inspects the case of the first letter of its own
   671 name); added separate "isabelle-process" and "isabelle-interface";
   672 
   673 * system: refrain from any attempt at filtering input streams; no
   674 longer support ``8bit'' encoding of old isabelle font, instead proper
   675 iso-latin characters may now be used; the related isatools
   676 "symbolinput" and "nonascii" have disappeared as well;
   677 
   678 * system: removed old "xterm" interface (the print modes "xterm" and
   679 "xterm_color" are still available for direct use in a suitable
   680 terminal);
   681 
   682 
   683 
   684 New in Isabelle99-2 (February 2001)
   685 -----------------------------------
   686 
   687 *** Overview of INCOMPATIBILITIES ***
   688 
   689 * HOL: please note that theories in the Library and elsewhere often use the
   690 new-style (Isar) format; to refer to their theorems in an ML script you must
   691 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   692 
   693 * HOL: inductive package no longer splits induction rule aggressively,
   694 but only as far as specified by the introductions given; the old
   695 format may be recovered via ML function complete_split_rule or attribute
   696 'split_rule (complete)';
   697 
   698 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   699 gfp_Tarski to gfp_unfold;
   700 
   701 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   702 
   703 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   704 relation); infix "^^" has been renamed "``"; infix "``" has been
   705 renamed "`"; "univalent" has been renamed "single_valued";
   706 
   707 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   708 operation;
   709 
   710 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   711 
   712 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   713 
   714 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   715 consequence, it is no longer monotonic wrt. the local goal context
   716 (which is now passed through the inductive cases);
   717 
   718 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   719 \<gg> to \<ggreater>;
   720 
   721 
   722 *** Document preparation ***
   723 
   724 * \isabellestyle{NAME} selects version of Isabelle output (currently
   725 available: are "it" for near math-mode best-style output, "sl" for
   726 slanted text style, and "tt" for plain type-writer; if no
   727 \isabellestyle command is given, output is according to slanted
   728 type-writer);
   729 
   730 * support sub/super scripts (for single symbols only), input syntax is
   731 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   732 
   733 * some more standard symbols; see Appendix A of the system manual for
   734 the complete list of symbols defined in isabellesym.sty;
   735 
   736 * improved isabelle style files; more abstract symbol implementation
   737 (should now use \isamath{...} and \isatext{...} in custom symbol
   738 definitions);
   739 
   740 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   741 state; Note that presentation of goal states does not conform to
   742 actual human-readable proof documents.  Please do not include goal
   743 states into document output unless you really know what you are doing!
   744 
   745 * proper indentation of antiquoted output with proportional LaTeX
   746 fonts;
   747 
   748 * no_document ML operator temporarily disables LaTeX document
   749 generation;
   750 
   751 * isatool unsymbolize tunes sources for plain ASCII communication;
   752 
   753 
   754 *** Isar ***
   755 
   756 * Pure: Isar now suffers initial goal statements to contain unbound
   757 schematic variables (this does not conform to actual readable proof
   758 documents, due to unpredictable outcome and non-compositional proof
   759 checking); users who know what they are doing may use schematic goals
   760 for Prolog-style synthesis of proven results;
   761 
   762 * Pure: assumption method (an implicit finishing) now handles actual
   763 rules as well;
   764 
   765 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   766 initial goal, declare "that" only as Pure intro (only for single
   767 steps); the "that" rule assumption may now be involved in implicit
   768 finishing, thus ".." becomes a feasible for trivial obtains;
   769 
   770 * Pure: default proof step now includes 'intro_classes'; thus trivial
   771 instance proofs may be performed by "..";
   772 
   773 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   774 statements as well;
   775 
   776 * Pure: more robust selection of calculational rules;
   777 
   778 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   779 rule (as well as the assumption rule);
   780 
   781 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   782 lemmas, using the graph browser tool;
   783 
   784 * Pure: predict failure of "show" in interactive mode;
   785 
   786 * Pure: 'thms_containing' now takes actual terms as arguments;
   787 
   788 * HOL: improved method 'induct' --- now handles non-atomic goals
   789 (potential INCOMPATIBILITY); tuned error handling;
   790 
   791 * HOL: cases and induct rules now provide explicit hints about the
   792 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   793 any remaining facts are inserted into the goal verbatim;
   794 
   795 * HOL: local contexts (aka cases) may now contain term bindings as
   796 well; the 'cases' and 'induct' methods new provide a ?case binding for
   797 the result to be shown in each case;
   798 
   799 * HOL: added 'recdef_tc' command;
   800 
   801 * isatool convert assists in eliminating legacy ML scripts;
   802 
   803 
   804 *** HOL ***
   805 
   806 * HOL/Library: a collection of generic theories to be used together
   807 with main HOL; the theory loader path already includes this directory
   808 by default; the following existing theories have been moved here:
   809 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   810 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   811 
   812 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   813 modelling and verification task performed in Isabelle/HOL +
   814 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   815 
   816 * HOL/Algebra: special summation operator SUM no longer exists, it has
   817 been replaced by setsum; infix 'assoc' now has priority 50 (like
   818 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   819 'domain', this makes the theory consistent with mathematical
   820 literature;
   821 
   822 * HOL basics: added overloaded operations "inverse" and "divide"
   823 (infix "/"), syntax for generic "abs" operation, generic summation
   824 operator \<Sum>;
   825 
   826 * HOL/typedef: simplified package, provide more useful rules (see also
   827 HOL/subset.thy);
   828 
   829 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   830 now expressed as a proper nested rule (old-style tactic scripts may
   831 require atomize_strip_tac to cope with non-atomic premises);
   832 
   833 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   834 to "split_conv" (old name still available for compatibility);
   835 
   836 * HOL: improved concrete syntax for strings (e.g. allows translation
   837 rules with string literals);
   838 
   839 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   840  and Fleuriot's mechanization of analysis, including the transcendental
   841  functions for the reals;
   842 
   843 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   844 
   845 
   846 *** CTT ***
   847 
   848 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   849 "lam" is displayed as TWO lambda-symbols
   850 
   851 * CTT: theory Main now available, containing everything (that is, Bool
   852 and Arith);
   853 
   854 
   855 *** General ***
   856 
   857 * Pure: the Simplifier has been implemented properly as a derived rule
   858 outside of the actual kernel (at last!); the overall performance
   859 penalty in practical applications is about 50%, while reliability of
   860 the Isabelle inference kernel has been greatly improved;
   861 
   862 * print modes "brackets" and "no_brackets" control output of nested =>
   863 (types) and ==> (props); the default behaviour is "brackets";
   864 
   865 * Provers: fast_tac (and friends) now handle actual object-logic rules
   866 as assumptions as well;
   867 
   868 * system: support Poly/ML 4.0;
   869 
   870 * system: isatool install handles KDE version 1 or 2;
   871 
   872 
   873 
   874 New in Isabelle99-1 (October 2000)
   875 ----------------------------------
   876 
   877 *** Overview of INCOMPATIBILITIES ***
   878 
   879 * HOL: simplification of natural numbers is much changed; to partly
   880 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   881 issue the following ML commands:
   882 
   883   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   884   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   885 
   886 * HOL: simplification no longer dives into case-expressions; this is
   887 controlled by "t.weak_case_cong" for each datatype t;
   888 
   889 * HOL: nat_less_induct renamed to less_induct;
   890 
   891 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   892 fixsome to patch .thy and .ML sources automatically;
   893 
   894   select_equality  -> some_equality
   895   select_eq_Ex     -> some_eq_ex
   896   selectI2EX       -> someI2_ex
   897   selectI2         -> someI2
   898   selectI          -> someI
   899   select1_equality -> some1_equality
   900   Eps_sym_eq       -> some_sym_eq_trivial
   901   Eps_eq           -> some_eq_trivial
   902 
   903 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   904 
   905 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   906 instead);
   907 
   908 * HOL: the recursion equations generated by 'recdef' are now called
   909 f.simps instead of f.rules;
   910 
   911 * HOL: qed_spec_mp now also handles bounded ALL as well;
   912 
   913 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   914 sometimes be needed;
   915 
   916 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   917 
   918 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   919 
   920 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   921 product is now "<*>" instead of "Times"; the lexicographic product is
   922 now "<*lex*>" instead of "**";
   923 
   924 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   925 of main HOL, but was unused); better use HOL's datatype package;
   926 
   927 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   928 the old syntax may be recovered as follows:
   929 
   930   syntax (symbols)
   931     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   932       (infixl "\\<oplus>" 100)
   933 
   934 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   935 
   936 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   937 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   938 internally;
   939 
   940 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   941 changed from A/r to A//r;
   942 
   943 * ZF: new treatment of arithmetic (nat & int) may break some old
   944 proofs;
   945 
   946 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   947 rulify -> rule_format, elimify -> elim_format, ...);
   948 
   949 * Isar/Provers: intro/elim/dest attributes changed; renamed
   950 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   951 should have to change intro!! to intro? only); replaced "delrule" by
   952 "rule del";
   953 
   954 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   955 
   956 * Provers: strengthened force_tac by using new first_best_tac;
   957 
   958 * LaTeX document preparation: several changes of isabelle.sty (see
   959 lib/texinputs);
   960 
   961 
   962 *** Document preparation ***
   963 
   964 * formal comments (text blocks etc.) in new-style theories may now
   965 contain antiquotations of thm/prop/term/typ/text to be presented
   966 according to latex print mode; concrete syntax is like this:
   967 @{term[show_types] "f(x) = a + x"};
   968 
   969 * isatool mkdir provides easy setup of Isabelle session directories,
   970 including proper document sources;
   971 
   972 * generated LaTeX sources are now deleted after successful run
   973 (isatool document -c); may retain a copy somewhere else via -D option
   974 of isatool usedir;
   975 
   976 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   977 style files, achieving self-contained LaTeX sources and simplifying
   978 LaTeX debugging;
   979 
   980 * old-style theories now produce (crude) LaTeX output as well;
   981 
   982 * browser info session directories are now self-contained (may be put
   983 on WWW server seperately); improved graphs of nested sessions; removed
   984 graph for 'all sessions';
   985 
   986 * several improvements in isabelle style files; \isabellestyle{it}
   987 produces fake math mode output; \isamarkupheader is now \section by
   988 default; see lib/texinputs/isabelle.sty etc.;
   989 
   990 
   991 *** Isar ***
   992 
   993 * Isar/Pure: local results and corresponding term bindings are now
   994 subject to Hindley-Milner polymorphism (similar to ML); this
   995 accommodates incremental type-inference very nicely;
   996 
   997 * Isar/Pure: new derived language element 'obtain' supports
   998 generalized existence reasoning;
   999 
  1000 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1001 support accumulation of results, without applying any rules yet;
  1002 useful to collect intermediate results without explicit name
  1003 references, and for use with transitivity rules with more than 2
  1004 premises;
  1005 
  1006 * Isar/Pure: scalable support for case-analysis type proofs: new
  1007 'case' language element refers to local contexts symbolically, as
  1008 produced by certain proof methods; internally, case names are attached
  1009 to theorems as "tags";
  1010 
  1011 * Isar/Pure: theory command 'hide' removes declarations from
  1012 class/type/const name spaces;
  1013 
  1014 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1015 indicate potential overloading;
  1016 
  1017 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1018 
  1019 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1020 "{a,b,c}" instead of {a,b,c};
  1021 
  1022 * Isar/Pure now provides its own version of intro/elim/dest
  1023 attributes; useful for building new logics, but beware of confusion
  1024 with the version in Provers/classical;
  1025 
  1026 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1027 case name 'antecedent';
  1028 
  1029 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1030 to the current context is now done automatically);
  1031 
  1032 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1033 for definining proof methods in ML;
  1034 
  1035 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1036 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1037 most cases, one should have to change intro!! to intro? only);
  1038 replaced "delrule" by "rule del";
  1039 
  1040 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1041 'symmetric' attribute (the latter supercedes [RS sym]);
  1042 
  1043 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1044 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1045 well (including splits);
  1046 
  1047 * Isar/Provers: Simplifier and Classical methods now support all kind
  1048 of modifiers used in the past, including 'cong', 'iff', etc.
  1049 
  1050 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1051 of Simplifier and Classical reasoner);
  1052 
  1053 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1054 now support named cases; major packages (inductive, datatype, primrec,
  1055 recdef) support case names and properly name parameters;
  1056 
  1057 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1058 monotonicity conditions are extracted to be proven at end of
  1059 calculations;
  1060 
  1061 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1062 method anyway;
  1063 
  1064 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1065 split_if split_if_asm; datatype package provides theorems foo.splits =
  1066 foo.split foo.split_asm for each datatype;
  1067 
  1068 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1069 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1070 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1071 use "(cases (simplified))" method in proper proof texts);
  1072 
  1073 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1074 
  1075 * Isar: names of theorems etc. may be natural numbers as well;
  1076 
  1077 * Isar: 'pr' command: optional arguments for goals_limit and
  1078 ProofContext.prems_limit; no longer prints theory contexts, but only
  1079 proof states;
  1080 
  1081 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1082 additional print modes to be specified; e.g. "pr(latex)" will print
  1083 proof state according to the Isabelle LaTeX style;
  1084 
  1085 * Isar: improved support for emulating tactic scripts, including proof
  1086 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1087 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1088 (for HOL datatypes);
  1089 
  1090 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1091 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1092 'proof method scripts' have to be in depth-first order;
  1093 
  1094 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1095 
  1096 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1097 should instead use individual commands for printing items
  1098 (print_commands, print_methods etc.);
  1099 
  1100 * Isar: added 'nothing' --- the empty list of theorems;
  1101 
  1102 
  1103 *** HOL ***
  1104 
  1105 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1106 corresponding virtual machine and a specification of its bytecode
  1107 verifier and a lightweight bytecode verifier, including proofs of
  1108 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1109 Cornelia Pusch (see also the homepage of project Bali at
  1110 http://isabelle.in.tum.de/Bali/);
  1111 
  1112 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1113 Clemens Ballarin;
  1114 
  1115 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1116 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1117 Rasmussen;
  1118 
  1119 * HOL/Lattice: fundamental concepts of lattice theory and order
  1120 structures, including duals, properties of bounds versus algebraic
  1121 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1122 Theorem for complete lattices etc.; may also serve as a demonstration
  1123 for abstract algebraic reasoning using axiomatic type classes, and
  1124 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1125 
  1126 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1127 von Oheimb;
  1128 
  1129 * HOL/IMPP: extension of IMP with local variables and mutually
  1130 recursive procedures, by David von Oheimb;
  1131 
  1132 * HOL/Lambda: converted into new-style theory and document;
  1133 
  1134 * HOL/ex/Multiquote: example of multiple nested quotations and
  1135 anti-quotations -- basically a generalized version of de-Bruijn
  1136 representation; very useful in avoiding lifting of operations;
  1137 
  1138 * HOL/record: added general record equality rule to simpset; fixed
  1139 select-update simplification procedure to handle extended records as
  1140 well; admit "r" as field name;
  1141 
  1142 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1143 other numeric types and also as the identity of groups, rings, etc.;
  1144 
  1145 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1146 Types nat and int belong to this axclass;
  1147 
  1148 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1149    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1150    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1151   two terms #m*u and #n*u are replaced by #(m+n)*u
  1152     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1153   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1154     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1155 
  1156 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1157 powerful prover for predicate logic but knows nothing of clasets; see
  1158 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1159 
  1160 * HOL: new version of "case_tac" subsumes both boolean case split and
  1161 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1162 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1163 
  1164 * HOL: simplification no longer dives into case-expressions: only the
  1165 selector expression is simplified, but not the remaining arms; to
  1166 enable full simplification of case-expressions for datatype t, you may
  1167 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1168 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1169 
  1170 * HOL/recdef: the recursion equations generated by 'recdef' for
  1171 function 'f' are now called f.simps instead of f.rules; if all
  1172 termination conditions are proved automatically, these simplification
  1173 rules are added to the simpset, as in primrec; rules may be named
  1174 individually as well, resulting in a separate list of theorems for
  1175 each equation;
  1176 
  1177 * HOL/While is a new theory that provides a while-combinator. It
  1178 permits the definition of tail-recursive functions without the
  1179 provision of a termination measure. The latter is necessary once the
  1180 invariant proof rule for while is applied.
  1181 
  1182 * HOL: new (overloaded) notation for the set of elements below/above
  1183 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1184 
  1185 * HOL: theorems impI, allI, ballI bound as "strip";
  1186 
  1187 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1188 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1189 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1190 
  1191 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1192 
  1193 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1194 main HOL, but was unused);
  1195 
  1196 * HOL: fewer consts declared as global (e.g. have to refer to
  1197 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1198 
  1199 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1200 in case of overlap with user translations (e.g. judgements over
  1201 tuples); (note that the underlying logical represenation is still
  1202 bogus);
  1203 
  1204 
  1205 *** ZF ***
  1206 
  1207 * ZF: simplification automatically cancels common terms in arithmetic
  1208 expressions over nat and int;
  1209 
  1210 * ZF: new treatment of nat to minimize type-checking: all operators
  1211 coerce their operands to a natural number using the function natify,
  1212 making the algebraic laws unconditional;
  1213 
  1214 * ZF: as above, for int: operators coerce their operands to an integer
  1215 using the function intify;
  1216 
  1217 * ZF: the integer library now contains many of the usual laws for the
  1218 orderings, including $<=, and monotonicity laws for $+ and $*;
  1219 
  1220 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1221 simplification;
  1222 
  1223 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1224 to the simplifier and classical reasoner simultaneously;
  1225 
  1226 
  1227 *** General ***
  1228 
  1229 * Provers: blast_tac now handles actual object-logic rules as
  1230 assumptions; note that auto_tac uses blast_tac internally as well;
  1231 
  1232 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1233 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1234 
  1235 * Provers: delrules now handles destruct rules as well (no longer need
  1236 explicit make_elim);
  1237 
  1238 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1239   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1240 use instead the strong form,
  1241   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1242 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1243 from destruct-rules;
  1244 
  1245 * Provers: Simplifier.easy_setup provides a fast path to basic
  1246 Simplifier setup for new object-logics;
  1247 
  1248 * Pure: AST translation rules no longer require constant head on LHS;
  1249 
  1250 * Pure: improved name spaces: ambiguous output is qualified; support
  1251 for hiding of names;
  1252 
  1253 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1254 XSYMBOL_HOME; no longer need to do manual configuration in most
  1255 situations;
  1256 
  1257 * system: compression of ML heaps images may now be controlled via -c
  1258 option of isabelle and isatool usedir (currently only observed by
  1259 Poly/ML);
  1260 
  1261 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1262 useful for remote X11);
  1263 
  1264 * system: provide TAGS file for Isabelle sources;
  1265 
  1266 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1267 order;
  1268 
  1269 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1270 timing flag supersedes proof_timing and Toplevel.trace;
  1271 
  1272 * ML: new combinators |>> and |>>> for incremental transformations
  1273 with secondary results (e.g. certain theory extensions):
  1274 
  1275 * ML: PureThy.add_defs gets additional argument to indicate potential
  1276 overloading (usually false);
  1277 
  1278 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1279 results;
  1280 
  1281 
  1282 
  1283 New in Isabelle99 (October 1999)
  1284 --------------------------------
  1285 
  1286 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1287 
  1288 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1289 are no longer simplified.  (This allows the simplifier to unfold recursive
  1290 functional programs.)  To restore the old behaviour, declare
  1291 
  1292     Delcongs [if_weak_cong];
  1293 
  1294 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1295 complement;
  1296 
  1297 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1298 
  1299 * HOL/datatype: mutual_induct_tac no longer exists --
  1300   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1301 
  1302 * HOL/typedef: fixed type inference for representing set; type
  1303 arguments now have to occur explicitly on the rhs as type constraints;
  1304 
  1305 * ZF: The con_defs part of an inductive definition may no longer refer
  1306 to constants declared in the same theory;
  1307 
  1308 * HOL, ZF: the function mk_cases, generated by the inductive
  1309 definition package, has lost an argument.  To simplify its result, it
  1310 uses the default simpset instead of a supplied list of theorems.
  1311 
  1312 * HOL/List: the constructors of type list are now Nil and Cons;
  1313 
  1314 * Simplifier: the type of the infix ML functions
  1315         setSSolver addSSolver setSolver addSolver
  1316 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1317 for packaging solvers. A solver is created via
  1318         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1319 where the string argument is only a comment.
  1320 
  1321 
  1322 *** Proof tools ***
  1323 
  1324 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1325 decision procedure for linear arithmetic. Currently it is used for
  1326 types `nat', `int', and `real' in HOL (see below); it can, should and
  1327 will be instantiated for other types and logics as well.
  1328 
  1329 * The simplifier now accepts rewrite rules with flexible heads, eg
  1330      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1331   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1332   matching.
  1333 
  1334 
  1335 *** General ***
  1336 
  1337 * New Isabelle/Isar subsystem provides an alternative to traditional
  1338 tactical theorem proving; together with the ProofGeneral/isar user
  1339 interface it offers an interactive environment for developing human
  1340 readable proof documents (Isar == Intelligible semi-automated
  1341 reasoning); for further information see isatool doc isar-ref,
  1342 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1343 
  1344 * improved and simplified presentation of theories: better HTML markup
  1345 (including colors), graph views in several sizes; isatool usedir now
  1346 provides a proper interface for user theories (via -P option); actual
  1347 document preparation based on (PDF)LaTeX is available as well (for
  1348 new-style theories only); see isatool doc system for more information;
  1349 
  1350 * native support for Proof General, both for classic Isabelle and
  1351 Isabelle/Isar;
  1352 
  1353 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1354 using the graph browser tool;
  1355 
  1356 * Isabelle manuals now also available as PDF;
  1357 
  1358 * theory loader rewritten from scratch (may not be fully
  1359 bug-compatible); old loadpath variable has been replaced by show_path,
  1360 add_path, del_path, reset_path functions; new operations such as
  1361 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1362 isatool doc ref);
  1363 
  1364 * improved isatool install: option -k creates KDE application icon,
  1365 option -p DIR installs standalone binaries;
  1366 
  1367 * added ML_PLATFORM setting (useful for cross-platform installations);
  1368 more robust handling of platform specific ML images for SML/NJ;
  1369 
  1370 * the settings environment is now statically scoped, i.e. it is never
  1371 created again in sub-processes invoked from isabelle, isatool, or
  1372 Isabelle;
  1373 
  1374 * path element specification '~~' refers to '$ISABELLE_HOME';
  1375 
  1376 * in locales, the "assumes" and "defines" parts may be omitted if
  1377 empty;
  1378 
  1379 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1380 long arrows);
  1381 
  1382 * new print_mode "HTML";
  1383 
  1384 * new flag show_tags controls display of tags of theorems (which are
  1385 basically just comments that may be attached by some tools);
  1386 
  1387 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1388 mode and goal output format:
  1389 
  1390 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1391 244c244
  1392 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1393 ---
  1394 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1395 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1396 181c181
  1397 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1398 ---
  1399 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1400 
  1401 * function bind_thms stores lists of theorems (cf. bind_thm);
  1402 
  1403 * new shorthand tactics ftac, eatac, datac, fatac;
  1404 
  1405 * qed (and friends) now accept "" as result name; in that case the
  1406 theorem is not stored, but proper checks and presentation of the
  1407 result still apply;
  1408 
  1409 * theorem database now also indexes constants "Trueprop", "all",
  1410 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1411 
  1412 
  1413 *** HOL ***
  1414 
  1415 ** HOL arithmetic **
  1416 
  1417 * There are now decision procedures for linear arithmetic over nat and
  1418 int:
  1419 
  1420 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1421 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1422 are treated as atomic; subformulae not involving type `nat' or `int'
  1423 are ignored; quantified subformulae are ignored unless they are
  1424 positive universal or negative existential. The tactic has to be
  1425 invoked by hand and can be a little bit slow. In particular, the
  1426 running time is exponential in the number of occurrences of `min' and
  1427 `max', and `-' on `nat'.
  1428 
  1429 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1430 (negated) (in)equalities among the premises and the conclusion into
  1431 account (i.e. no compound formulae) and does not know about `min' and
  1432 `max', and `-' on `nat'. It is fast and is used automatically by the
  1433 simplifier.
  1434 
  1435 NB: At the moment, these decision procedures do not cope with mixed
  1436 nat/int formulae where the two parts interact, such as `m < n ==>
  1437 int(m) < int(n)'.
  1438 
  1439 * HOL/Numeral provides a generic theory of numerals (encoded
  1440 efficiently as bit strings); setup for types nat/int/real is in place;
  1441 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1442 int, existing theories and proof scripts may require a few additional
  1443 type constraints;
  1444 
  1445 * integer division and remainder can now be performed on constant
  1446 arguments;
  1447 
  1448 * many properties of integer multiplication, division and remainder
  1449 are now available;
  1450 
  1451 * An interface to the Stanford Validity Checker (SVC) is available through the
  1452 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1453 are proved automatically.  SVC must be installed separately, and its results
  1454 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1455 invocation of the underlying oracle).  For SVC see
  1456   http://verify.stanford.edu/SVC
  1457 
  1458 * IsaMakefile: the HOL-Real target now builds an actual image;
  1459 
  1460 
  1461 ** HOL misc **
  1462 
  1463 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1464 (in Isabelle/Isar) -- by Gertrud Bauer;
  1465 
  1466 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1467 analysis for assembly languages with subtypes;
  1468 
  1469 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1470 -- avoids syntactic ambiguities and treats state, transition, and
  1471 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1472 changed syntax and (many) tactics;
  1473 
  1474 * HOL/inductive: Now also handles more general introduction rules such
  1475   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1476   theorems are now maintained within the theory (maintained via the
  1477   "mono" attribute);
  1478 
  1479 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1480   (using function types) such as
  1481 
  1482   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1483 
  1484 * HOL/record: record_simproc (part of the default simpset) takes care
  1485 of selectors applied to updated records; record_split_tac is no longer
  1486 part of the default claset; update_defs may now be removed from the
  1487 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1488 
  1489   claset_ref () := claset() addSWrapper record_split_wrapper;
  1490   Delsimprocs [record_simproc]
  1491 
  1492 * HOL/typedef: fixed type inference for representing set; type
  1493 arguments now have to occur explicitly on the rhs as type constraints;
  1494 
  1495 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1496 names rather than an ML expression;
  1497 
  1498 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1499 supplied later.  Program schemes can be defined, such as
  1500     "While B C s = (if B s then While B C (C s) else s)"
  1501 where the well-founded relation can be chosen after B and C have been given.
  1502 
  1503 * HOL/List: the constructors of type list are now Nil and Cons;
  1504 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1505 course, ML tools referring to List.list.op # etc. have to be adapted;
  1506 
  1507 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1508 disabled by default; run isabelle with option -m HOL to get back to
  1509 the original Gordon/HOL-style output;
  1510 
  1511 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1512 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1513 
  1514 * HOL basic syntax simplified (more orthogonal): all variants of
  1515 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1516 Eps operator is provided as well: "SOME x. P[x]";
  1517 
  1518 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1519 
  1520 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1521 thus available for user theories;
  1522 
  1523 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1524 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1525 time;
  1526 
  1527 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1528 several times and then mp;
  1529 
  1530 
  1531 *** LK ***
  1532 
  1533 * the notation <<...>> is now available as a notation for sequences of
  1534 formulas;
  1535 
  1536 * the simplifier is now installed
  1537 
  1538 * the axiom system has been generalized (thanks to Soren Heilmann)
  1539 
  1540 * the classical reasoner now has a default rule database
  1541 
  1542 
  1543 *** ZF ***
  1544 
  1545 * new primrec section allows primitive recursive functions to be given
  1546 directly (as in HOL) over datatypes and the natural numbers;
  1547 
  1548 * new tactics induct_tac and exhaust_tac for induction (or case
  1549 analysis) over datatypes and the natural numbers;
  1550 
  1551 * the datatype declaration of type T now defines the recursor T_rec;
  1552 
  1553 * simplification automatically does freeness reasoning for datatype
  1554 constructors;
  1555 
  1556 * automatic type-inference, with AddTCs command to insert new
  1557 type-checking rules;
  1558 
  1559 * datatype introduction rules are now added as Safe Introduction rules
  1560 to the claset;
  1561 
  1562 * the syntax "if P then x else y" is now available in addition to
  1563 if(P,x,y);
  1564 
  1565 
  1566 *** Internal programming interfaces ***
  1567 
  1568 * tuned simplifier trace output; new flag debug_simp;
  1569 
  1570 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1571 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1572 
  1573 * AxClass.axclass_tac lost the theory argument;
  1574 
  1575 * tuned current_goals_markers semantics: begin / end goal avoids
  1576 printing empty lines;
  1577 
  1578 * removed prs and prs_fn hook, which was broken because it did not
  1579 include \n in its semantics, forcing writeln to add one
  1580 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1581 string -> unit if you really want to output text without newline;
  1582 
  1583 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1584 plain output, interface builders may have to enable 'isabelle_font'
  1585 mode to get Isabelle font glyphs as before;
  1586 
  1587 * refined token_translation interface; INCOMPATIBILITY: output length
  1588 now of type real instead of int;
  1589 
  1590 * theory loader actions may be traced via new ThyInfo.add_hook
  1591 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1592 your own database of information attached to *whole* theories -- as
  1593 opposed to intra-theory data slots offered via TheoryDataFun;
  1594 
  1595 * proper handling of dangling sort hypotheses (at last!);
  1596 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1597 extra sort hypotheses that can be witnessed from the type signature;
  1598 the force_strip_shyps flag is gone, any remaining shyps are simply
  1599 left in the theorem (with a warning issued by strip_shyps_warning);
  1600 
  1601 
  1602 
  1603 New in Isabelle98-1 (October 1998)
  1604 ----------------------------------
  1605 
  1606 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1607 
  1608 * several changes of automated proof tools;
  1609 
  1610 * HOL: major changes to the inductive and datatype packages, including
  1611 some minor incompatibilities of theory syntax;
  1612 
  1613 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1614 called `inj_on';
  1615 
  1616 * HOL: removed duplicate thms in Arith:
  1617   less_imp_add_less  should be replaced by  trans_less_add1
  1618   le_imp_add_le      should be replaced by  trans_le_add1
  1619 
  1620 * HOL: unary minus is now overloaded (new type constraints may be
  1621 required);
  1622 
  1623 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1624 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1625 now taken as an integer constant.
  1626 
  1627 * Pure: ML function 'theory_of' renamed to 'theory';
  1628 
  1629 
  1630 *** Proof tools ***
  1631 
  1632 * Simplifier:
  1633   1. Asm_full_simp_tac is now more aggressive.
  1634      1. It will sometimes reorient premises if that increases their power to
  1635         simplify.
  1636      2. It does no longer proceed strictly from left to right but may also
  1637         rotate premises to achieve further simplification.
  1638      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1639      old Asm_full_simp_tac in that it does not rotate premises.
  1640   2. The simplifier now knows a little bit about nat-arithmetic.
  1641 
  1642 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1643 allows for selected deletion of wrappers, by introduction of names for
  1644 wrapper functionals.  This implies that addbefore, addSbefore,
  1645 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1646 and that adding two tactics with the same name overwrites the first
  1647 one (emitting a warning).
  1648   type wrapper = (int -> tactic) -> (int -> tactic)
  1649   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1650   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1651   delWrapper, delSWrapper: claset *  string            -> claset
  1652   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1653 
  1654 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1655 semantics; addbefore now affects only the unsafe part of step_tac
  1656 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1657 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1658 by Force_tac;
  1659 
  1660 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1661 compWrapper; added safe wrapper (and access functions for it);
  1662 
  1663 * HOL/split_all_tac is now much faster and fails if there is nothing
  1664 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1665 and the names of the automatically generated variables have changed.
  1666 split_all_tac has moved within claset() from unsafe wrappers to safe
  1667 wrappers, which means that !!-bound variables are split much more
  1668 aggressively, and safe_tac and clarify_tac now split such variables.
  1669 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1670 Note: the same holds for record_split_tac, which does the job of
  1671 split_all_tac for record fields.
  1672 
  1673 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1674 permanently to the default simpset using Addsplits just like
  1675 Addsimps. They can be removed via Delsplits just like
  1676 Delsimps. Lower-case versions are also available.
  1677 
  1678 * HOL/Simplifier: The rule split_if is now part of the default
  1679 simpset. This means that the simplifier will eliminate all occurrences
  1680 of if-then-else in the conclusion of a goal. To prevent this, you can
  1681 either remove split_if completely from the default simpset by
  1682 `Delsplits [split_if]' or remove it in a specific call of the
  1683 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1684 other case splitting rules to/from the default simpset: every datatype
  1685 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1686 t is the name of the datatype).
  1687 
  1688 * Classical reasoner / Simplifier combination: new force_tac (and
  1689 derivatives Force_tac, force) combines rewriting and classical
  1690 reasoning (and whatever other tools) similarly to auto_tac, but is
  1691 aimed to solve the given subgoal completely.
  1692 
  1693 
  1694 *** General ***
  1695 
  1696 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1697 and `goalw': the theory is no longer needed as an explicit argument -
  1698 the current theory context is used; assumptions are no longer returned
  1699 at the ML-level unless one of them starts with ==> or !!; it is
  1700 recommended to convert to these new commands using isatool fixgoal
  1701 (backup your sources first!);
  1702 
  1703 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1704 the current theory context, and 'theory' to lookup stored theories;
  1705 
  1706 * new theory section 'locale' for declaring constants, assumptions and
  1707 definitions that have local scope;
  1708 
  1709 * new theory section 'nonterminals' for purely syntactic types;
  1710 
  1711 * new theory section 'setup' for generic ML setup functions
  1712 (e.g. package initialization);
  1713 
  1714 * the distribution now includes Isabelle icons: see
  1715 lib/logo/isabelle-{small,tiny}.xpm;
  1716 
  1717 * isatool install - install binaries with absolute references to
  1718 ISABELLE_HOME/bin;
  1719 
  1720 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1721 
  1722 * print mode 'emacs' reserved for Isamode;
  1723 
  1724 * support multiple print (ast) translations per constant name;
  1725 
  1726 * theorems involving oracles are now printed with a suffixed [!];
  1727 
  1728 
  1729 *** HOL ***
  1730 
  1731 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1732 
  1733 * HOL/inductive package reorganized and improved: now supports mutual
  1734 definitions such as
  1735 
  1736   inductive EVEN ODD
  1737     intrs
  1738       null "0 : EVEN"
  1739       oddI "n : EVEN ==> Suc n : ODD"
  1740       evenI "n : ODD ==> Suc n : EVEN"
  1741 
  1742 new theorem list "elims" contains an elimination rule for each of the
  1743 recursive sets; inductive definitions now handle disjunctive premises
  1744 correctly (also ZF);
  1745 
  1746 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1747 "mutual_induct" no longer exists - the induction rule is always
  1748 contained in "induct";
  1749 
  1750 
  1751 * HOL/datatype package re-implemented and greatly improved: now
  1752 supports mutually recursive datatypes such as
  1753 
  1754   datatype
  1755     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1756             | SUM ('a aexp) ('a aexp)
  1757             | DIFF ('a aexp) ('a aexp)
  1758             | NUM 'a
  1759   and
  1760     'a bexp = LESS ('a aexp) ('a aexp)
  1761             | AND ('a bexp) ('a bexp)
  1762             | OR ('a bexp) ('a bexp)
  1763 
  1764 as well as indirectly recursive datatypes such as
  1765 
  1766   datatype
  1767     ('a, 'b) term = Var 'a
  1768                   | App 'b ((('a, 'b) term) list)
  1769 
  1770 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1771 induction on mutually / indirectly recursive datatypes.
  1772 
  1773 Primrec equations are now stored in theory and can be accessed via
  1774 <function_name>.simps.
  1775 
  1776 INCOMPATIBILITIES:
  1777 
  1778   - Theories using datatypes must now have theory Datatype as an
  1779     ancestor.
  1780   - The specific <typename>.induct_tac no longer exists - use the
  1781     generic induct_tac instead.
  1782   - natE has been renamed to nat.exhaust - use exhaust_tac
  1783     instead of res_inst_tac ... natE. Note that the variable
  1784     names in nat.exhaust differ from the names in natE, this
  1785     may cause some "fragile" proofs to fail.
  1786   - The theorems split_<typename>_case and split_<typename>_case_asm
  1787     have been renamed to <typename>.split and <typename>.split_asm.
  1788   - Since default sorts of type variables are now handled correctly,
  1789     some datatype definitions may have to be annotated with explicit
  1790     sort constraints.
  1791   - Primrec definitions no longer require function name and type
  1792     of recursive argument.
  1793 
  1794 Consider using isatool fixdatatype to adapt your theories and proof
  1795 scripts to the new package (backup your sources first!).
  1796 
  1797 
  1798 * HOL/record package: considerably improved implementation; now
  1799 includes concrete syntax for record types, terms, updates; theorems
  1800 for surjective pairing and splitting !!-bound record variables; proof
  1801 support is as follows:
  1802 
  1803   1) standard conversions (selectors or updates applied to record
  1804 constructor terms) are part of the standard simpset;
  1805 
  1806   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1807 made part of standard simpset and claset via addIffs;
  1808 
  1809   3) a tactic for record field splitting (record_split_tac) is part of
  1810 the standard claset (addSWrapper);
  1811 
  1812 To get a better idea about these rules you may retrieve them via
  1813 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1814 the name of your record type.
  1815 
  1816 The split tactic 3) conceptually simplifies by the following rule:
  1817 
  1818   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1819 
  1820 Thus any record variable that is bound by meta-all will automatically
  1821 blow up into some record constructor term, consequently the
  1822 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1823 solve record problems automatically.
  1824 
  1825 
  1826 * reorganized the main HOL image: HOL/Integ and String loaded by
  1827 default; theory Main includes everything;
  1828 
  1829 * automatic simplification of integer sums and comparisons, using cancellation;
  1830 
  1831 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1832 
  1833 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1834 
  1835 * many new identities for unions, intersections, set difference, etc.;
  1836 
  1837 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1838 called split_if, split_split, split_sum_case and split_nat_case (to go
  1839 with add/delsplits);
  1840 
  1841 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1842 (?x::unit) = (); this is made part of the default simpset, which COULD
  1843 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1844 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1845 unit_abs_eta_conv is added in order to counter the effect of
  1846 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1847 %u.f();
  1848 
  1849 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1850 makes more sense);
  1851 
  1852 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1853   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1854   disjointness reasoning but breaking a few old proofs.
  1855 
  1856 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1857 to 'converse' from 'inverse' (for compatibility with ZF and some
  1858 literature);
  1859 
  1860 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1861 the well-founded relation;
  1862 
  1863 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1864     Compl A.  The "Compl" syntax remains available as input syntax for this
  1865     release ONLY.
  1866 
  1867 * HOL/Update: new theory of function updates:
  1868     f(a:=b) == %x. if x=a then b else f x
  1869 may also be iterated as in f(a:=b,c:=d,...);
  1870 
  1871 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1872 
  1873 * HOL/List:
  1874   - new function list_update written xs[i:=v] that updates the i-th
  1875     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1876   - new function `upt' written [i..j(] which generates the list
  1877     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1878     bound write [i..j], which is a shorthand for [i..j+1(].
  1879   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1880 
  1881 * HOL/Arith:
  1882   - removed 'pred' (predecessor) function;
  1883   - generalized some theorems about n-1;
  1884   - many new laws about "div" and "mod";
  1885   - new laws about greatest common divisors (see theory ex/Primes);
  1886 
  1887 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1888 instead of "inverse";
  1889 
  1890 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1891   of the multiset ordering;
  1892 
  1893 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1894   (not included by default);
  1895 
  1896 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1897 
  1898 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1899   programs, i.e. different program variables may have different types.
  1900 
  1901 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1902   [previously, this check worked only if the rewrite rule was unconditional]
  1903   Now rew can involve either definitions or equalities (either == or =).
  1904 
  1905 
  1906 *** ZF ***
  1907 
  1908 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1909   only the theorems proved on ZF.ML;
  1910 
  1911 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1912   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1913   disjointness reasoning but breaking a few old proofs.
  1914 
  1915 * ZF/Update: new theory of function updates
  1916     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1917   may also be iterated as in f(a:=b,c:=d,...);
  1918 
  1919 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1920 
  1921 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1922   [previously, this check worked only if the rewrite rule was unconditional]
  1923   Now rew can involve either definitions or equalities (either == or =).
  1924 
  1925 * case_tac provided for compatibility with HOL
  1926     (like the old excluded_middle_tac, but with subgoals swapped)
  1927 
  1928 
  1929 *** Internal programming interfaces ***
  1930 
  1931 * Pure: several new basic modules made available for general use, see
  1932 also src/Pure/README;
  1933 
  1934 * improved the theory data mechanism to support encapsulation (data
  1935 kind name replaced by private Object.kind, acting as authorization
  1936 key); new type-safe user interface via functor TheoryDataFun; generic
  1937 print_data function becomes basically useless;
  1938 
  1939 * removed global_names compatibility flag -- all theory declarations
  1940 are qualified by default;
  1941 
  1942 * module Pure/Syntax now offers quote / antiquote translation
  1943 functions (useful for Hoare logic etc. with implicit dependencies);
  1944 see HOL/ex/Antiquote for an example use;
  1945 
  1946 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1947 cterm -> thm;
  1948 
  1949 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1950 subgoal;
  1951 
  1952 * Display.print_goals function moved to Locale.print_goals;
  1953 
  1954 * standard print function for goals supports current_goals_markers
  1955 variable for marking begin of proof, end of proof, start of goal; the
  1956 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1957 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1958 for example;
  1959 
  1960 
  1961 
  1962 New in Isabelle98 (January 1998)
  1963 --------------------------------
  1964 
  1965 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1966 
  1967 * changed lexical syntax of terms / types: dots made part of long
  1968 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1969 
  1970 * simpset (and claset) reference variable replaced by functions
  1971 simpset / simpset_ref;
  1972 
  1973 * no longer supports theory aliases (via merge) and non-trivial
  1974 implicit merge of thms' signatures;
  1975 
  1976 * most internal names of constants changed due to qualified names;
  1977 
  1978 * changed Pure/Sequence interface (see Pure/seq.ML);
  1979 
  1980 
  1981 *** General Changes ***
  1982 
  1983 * hierachically structured name spaces (for consts, types, axms, thms
  1984 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1985 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1986 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1987 long_names for fully qualified output names; NOTE: ML programs
  1988 (special tactics, packages etc.) referring to internal names may have
  1989 to be adapted to cope with fully qualified names; in case of severe
  1990 backward campatibility problems try setting 'global_names' at compile
  1991 time to have enrything declared within a flat name space; one may also
  1992 fine tune name declarations in theories via the 'global' and 'local'
  1993 section;
  1994 
  1995 * reimplemented the implicit simpset and claset using the new anytype
  1996 data filed in signatures; references simpset:simpset ref etc. are
  1997 replaced by functions simpset:unit->simpset and
  1998 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1999 to patch your ML files accordingly;
  2000 
  2001 * HTML output now includes theory graph data for display with Java
  2002 applet or isatool browser; data generated automatically via isatool
  2003 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2004 
  2005 * defs may now be conditional; improved rewrite_goals_tac to handle
  2006 conditional equations;
  2007 
  2008 * defs now admits additional type arguments, using TYPE('a) syntax;
  2009 
  2010 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2011 creates a new theory node; implicit merge of thms' signatures is
  2012 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2013 transfer:theory->thm->thm in (rare) cases;
  2014 
  2015 * improved handling of draft signatures / theories; draft thms (and
  2016 ctyps, cterms) are automatically promoted to real ones;
  2017 
  2018 * slightly changed interfaces for oracles: admit many per theory, named
  2019 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2020 
  2021 * print_goals: optional output of const types (set show_consts and
  2022 show_types);
  2023 
  2024 * improved output of warnings (###) and errors (***);
  2025 
  2026 * subgoal_tac displays a warning if the new subgoal has type variables;
  2027 
  2028 * removed old README and Makefiles;
  2029 
  2030 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2031 
  2032 * removed obsolete init_pps and init_database;
  2033 
  2034 * deleted the obsolete tactical STATE, which was declared by
  2035     fun STATE tacfun st = tacfun st st;
  2036 
  2037 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2038 (which abbreviates $HOME);
  2039 
  2040 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2041 use isatool fixseq to adapt your ML programs (this works for fully
  2042 qualified references to the Sequence structure only!);
  2043 
  2044 * use_thy no longer requires writable current directory; it always
  2045 reloads .ML *and* .thy file, if either one is out of date;
  2046 
  2047 
  2048 *** Classical Reasoner ***
  2049 
  2050 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2051 tactics that use classical reasoning to simplify a subgoal without
  2052 splitting it into several subgoals;
  2053 
  2054 * Safe_tac: like safe_tac but uses the default claset;
  2055 
  2056 
  2057 *** Simplifier ***
  2058 
  2059 * added simplification meta rules:
  2060     (asm_)(full_)simplify: simpset -> thm -> thm;
  2061 
  2062 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2063 logics (again);
  2064 
  2065 * added prems argument to simplification procedures;
  2066 
  2067 * HOL, FOL, ZF: added infix function `addsplits':
  2068   instead of `<simpset> setloop (split_tac <thms>)'
  2069   you can simply write `<simpset> addsplits <thms>'
  2070 
  2071 
  2072 *** Syntax ***
  2073 
  2074 * TYPE('a) syntax for type reflection terms;
  2075 
  2076 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2077 
  2078 * pretty printer: changed order of mixfix annotation preference (again!);
  2079 
  2080 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2081 
  2082 
  2083 *** HOL ***
  2084 
  2085 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2086   with `addloop' of the simplifier to faciliate case splitting in premises.
  2087 
  2088 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2089 
  2090 * HOL/Auth: new protocol proofs including some for the Internet
  2091   protocol TLS;
  2092 
  2093 * HOL/Map: new theory of `maps' a la VDM;
  2094 
  2095 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2096 cancelling out common nat summands from =, <, <= (in)equalities, or
  2097 differences; simplification procedures nat_cancel_factor for
  2098 cancelling common factor from =, <, <= (in)equalities over natural
  2099 sums; nat_cancel contains both kinds of procedures, it is installed by
  2100 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2101 
  2102 * HOL/simplifier: terms of the form
  2103   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2104   are rewritten to
  2105   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2106   and those of the form
  2107   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2108   are rewritten to
  2109   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2110 
  2111 * HOL/datatype
  2112   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2113 
  2114   P(t_case f1 ... fn x) =
  2115      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2116         ...
  2117        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2118      )
  2119 
  2120   and a theorem `split_t_case_asm' of the form
  2121 
  2122   P(t_case f1 ... fn x) =
  2123     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2124         ...
  2125        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2126      )
  2127   which can be added to a simpset via `addsplits'. The existing theorems
  2128   expand_list_case and expand_option_case have been renamed to
  2129   split_list_case and split_option_case.
  2130 
  2131 * HOL/Arithmetic:
  2132   - `pred n' is automatically converted to `n-1'.
  2133     Users are strongly encouraged not to use `pred' any longer,
  2134     because it will disappear altogether at some point.
  2135   - Users are strongly encouraged to write "0 < n" rather than
  2136     "n ~= 0". Theorems and proof tools have been modified towards this
  2137     `standard'.
  2138 
  2139 * HOL/Lists:
  2140   the function "set_of_list" has been renamed "set" (and its theorems too);
  2141   the function "nth" now takes its arguments in the reverse order and
  2142   has acquired the infix notation "!" as in "xs!n".
  2143 
  2144 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2145 
  2146 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2147   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2148 
  2149 * HOL/record: extensible records with schematic structural subtyping
  2150 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2151 still lacks various theorems and concrete record syntax;
  2152 
  2153 
  2154 *** HOLCF ***
  2155 
  2156 * removed "axioms" and "generated by" sections;
  2157 
  2158 * replaced "ops" section by extended "consts" section, which is capable of
  2159   handling the continuous function space "->" directly;
  2160 
  2161 * domain package:
  2162   . proves theorems immediately and stores them in the theory,
  2163   . creates hierachical name space,
  2164   . now uses normal mixfix annotations (instead of cinfix...),
  2165   . minor changes to some names and values (for consistency),
  2166   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2167   . separator between mutual domain defs: changed "," to "and",
  2168   . improved handling of sort constraints;  now they have to
  2169     appear on the left-hand side of the equations only;
  2170 
  2171 * fixed LAM <x,y,zs>.b syntax;
  2172 
  2173 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2174 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2175 
  2176 
  2177 *** FOL and ZF ***
  2178 
  2179 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2180   with `addloop' of the simplifier to faciliate case splitting in premises.
  2181 
  2182 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2183 in HOL, they strip ALL and --> from proved theorems;
  2184 
  2185 
  2186 
  2187 New in Isabelle94-8 (May 1997)
  2188 ------------------------------
  2189 
  2190 *** General Changes ***
  2191 
  2192 * new utilities to build / run / maintain Isabelle etc. (in parts
  2193 still somewhat experimental); old Makefiles etc. still functional;
  2194 
  2195 * new 'Isabelle System Manual';
  2196 
  2197 * INSTALL text, together with ./configure and ./build scripts;
  2198 
  2199 * reimplemented type inference for greater efficiency, better error
  2200 messages and clean internal interface;
  2201 
  2202 * prlim command for dealing with lots of subgoals (an easier way of
  2203 setting goals_limit);
  2204 
  2205 
  2206 *** Syntax ***
  2207 
  2208 * supports alternative (named) syntax tables (parser and pretty
  2209 printer); internal interface is provided by add_modesyntax(_i);
  2210 
  2211 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2212 be used in conjunction with the Isabelle symbol font; uses the
  2213 "symbols" syntax table;
  2214 
  2215 * added token_translation interface (may translate name tokens in
  2216 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2217 the current print_mode); IMPORTANT: user print translation functions
  2218 are responsible for marking newly introduced bounds
  2219 (Syntax.mark_boundT);
  2220 
  2221 * token translations for modes "xterm" and "xterm_color" that display
  2222 names in bold, underline etc. or colors (which requires a color
  2223 version of xterm);
  2224 
  2225 * infixes may now be declared with names independent of their syntax;
  2226 
  2227 * added typed_print_translation (like print_translation, but may
  2228 access type of constant);
  2229 
  2230 
  2231 *** Classical Reasoner ***
  2232 
  2233 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2234 some limitations.  Blast_tac...
  2235   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2236   + ignores elimination rules that don't have the correct format
  2237         (the conclusion MUST be a formula variable)
  2238   + ignores types, which can make HOL proofs fail
  2239   + rules must not require higher-order unification, e.g. apply_type in ZF
  2240     [message "Function Var's argument not a bound variable" relates to this]
  2241   + its proof strategy is more general but can actually be slower
  2242 
  2243 * substitution with equality assumptions no longer permutes other
  2244 assumptions;
  2245 
  2246 * minor changes in semantics of addafter (now called addaltern); renamed
  2247 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2248 (and access functions for it);
  2249 
  2250 * improved combination of classical reasoner and simplifier:
  2251   + functions for handling clasimpsets
  2252   + improvement of addss: now the simplifier is called _after_ the
  2253     safe steps.
  2254   + safe variant of addss called addSss: uses safe simplifications
  2255     _during_ the safe steps. It is more complete as it allows multiple
  2256     instantiations of unknowns (e.g. with slow_tac).
  2257 
  2258 *** Simplifier ***
  2259 
  2260 * added interface for simplification procedures (functions that
  2261 produce *proven* rewrite rules on the fly, depending on current
  2262 redex);
  2263 
  2264 * ordering on terms as parameter (used for ordered rewriting);
  2265 
  2266 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2267 
  2268 * the solver is now split into a safe and an unsafe part.
  2269 This should be invisible for the normal user, except that the
  2270 functions setsolver and addsolver have been renamed to setSolver and
  2271 addSolver; added safe_asm_full_simp_tac;
  2272 
  2273 
  2274 *** HOL ***
  2275 
  2276 * a generic induction tactic `induct_tac' which works for all datatypes and
  2277 also for type `nat';
  2278 
  2279 * a generic case distinction tactic `exhaust_tac' which works for all
  2280 datatypes and also for type `nat';
  2281 
  2282 * each datatype comes with a function `size';
  2283 
  2284 * patterns in case expressions allow tuple patterns as arguments to
  2285 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2286 
  2287 * primrec now also works with type nat;
  2288 
  2289 * recdef: a new declaration form, allows general recursive functions to be
  2290 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2291 
  2292 * the constant for negation has been renamed from "not" to "Not" to
  2293 harmonize with FOL, ZF, LK, etc.;
  2294 
  2295 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2296 infinite lists;
  2297 
  2298 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2299 
  2300 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2301 problems in commutative rings, using axiomatic type classes for + and *;
  2302 
  2303 * more examples in HOL/MiniML and HOL/Auth;
  2304 
  2305 * more default rewrite rules for quantifiers, union/intersection;
  2306 
  2307 * a new constant `arbitrary == @x.False';
  2308 
  2309 * HOLCF/IOA replaces old HOL/IOA;
  2310 
  2311 * HOLCF changes: derived all rules and arities
  2312   + axiomatic type classes instead of classes
  2313   + typedef instead of faking type definitions
  2314   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2315   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2316   + eliminated the types void, one, tr
  2317   + use unit lift and bool lift (with translations) instead of one and tr
  2318   + eliminated blift from Lift3.thy (use Def instead of blift)
  2319   all eliminated rules are derived as theorems --> no visible changes ;
  2320 
  2321 
  2322 *** ZF ***
  2323 
  2324 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2325 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2326 as ZF_cs addSIs [equalityI];
  2327 
  2328 
  2329 
  2330 New in Isabelle94-7 (November 96)
  2331 ---------------------------------
  2332 
  2333 * allowing negative levels (as offsets) in prlev and choplev;
  2334 
  2335 * super-linear speedup for large simplifications;
  2336 
  2337 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2338 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2339 FAIL); can suppress it using the command Delsimps (ex_simps @
  2340 all_simps); De Morgan laws are also now included, by default;
  2341 
  2342 * improved printing of ==>  :  ~:
  2343 
  2344 * new object-logic "Sequents" adds linear logic, while replacing LK
  2345 and Modal (thanks to Sara Kalvala);
  2346 
  2347 * HOL/Auth: correctness proofs for authentication protocols;
  2348 
  2349 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2350 examples on HOL/Auth);
  2351 
  2352 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2353 the rewriter and classical reasoner simultaneously;
  2354 
  2355 * function uresult no longer returns theorems in "standard" format;
  2356 regain previous version by: val uresult = standard o uresult;
  2357 
  2358 
  2359 
  2360 New in Isabelle94-6
  2361 -------------------
  2362 
  2363 * oracles -- these establish an interface between Isabelle and trusted
  2364 external reasoners, which may deliver results as theorems;
  2365 
  2366 * proof objects (in particular record all uses of oracles);
  2367 
  2368 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2369 
  2370 * "constdefs" section in theory files;
  2371 
  2372 * "primrec" section (HOL) no longer requires names;
  2373 
  2374 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2375 
  2376 
  2377 
  2378 New in Isabelle94-5
  2379 -------------------
  2380 
  2381 * reduced space requirements;
  2382 
  2383 * automatic HTML generation from theories;
  2384 
  2385 * theory files no longer require "..." (quotes) around most types;
  2386 
  2387 * new examples, including two proofs of the Church-Rosser theorem;
  2388 
  2389 * non-curried (1994) version of HOL is no longer distributed;
  2390 
  2391 
  2392 
  2393 New in Isabelle94-4
  2394 -------------------
  2395 
  2396 * greatly reduced space requirements;
  2397 
  2398 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2399 
  2400 * searchable theorem database (see the section "Retrieving theorems" on
  2401 page 8 of the Reference Manual);
  2402 
  2403 * new examples, including Grabczewski's monumental case study of the
  2404 Axiom of Choice;
  2405 
  2406 * The previous version of HOL renamed to Old_HOL;
  2407 
  2408 * The new version of HOL (previously called CHOL) uses a curried syntax
  2409 for functions.  Application looks like f a b instead of f(a,b);
  2410 
  2411 * Mutually recursive inductive definitions finally work in HOL;
  2412 
  2413 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2414 translates to the operator "split";
  2415 
  2416 
  2417 
  2418 New in Isabelle94-3
  2419 -------------------
  2420 
  2421 * new infix operator, addss, allowing the classical reasoner to
  2422 perform simplification at each step of its search.  Example:
  2423         fast_tac (cs addss ss)
  2424 
  2425 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2426 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2427 look like (a,b) instead of <a,b>;
  2428 
  2429 * PLEASE NOTE: CHOL will eventually replace HOL!
  2430 
  2431 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2432 It translates to the operator "split".  A new theory of integers is available;
  2433 
  2434 * In ZF, integer numerals now denote two's-complement binary integers.
  2435 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2436 
  2437 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2438 of the Axiom of Choice;
  2439 
  2440 
  2441 
  2442 New in Isabelle94-2
  2443 -------------------
  2444 
  2445 * Significantly faster resolution;
  2446 
  2447 * the different sections in a .thy file can now be mixed and repeated
  2448 freely;
  2449 
  2450 * Database of theorems for FOL, HOL and ZF.  New
  2451 commands including qed, qed_goal and bind_thm store theorems in the database.
  2452 
  2453 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2454 a given theory (thms_of), or find out what theory a theorem was proved in
  2455 (theory_of_thm);
  2456 
  2457 * Bugs fixed in the inductive definition and datatype packages;
  2458 
  2459 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2460 and HOL_dup_cs obsolete;
  2461 
  2462 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2463 have been removed;
  2464 
  2465 * Simpler definition of function space in ZF;
  2466 
  2467 * new results about cardinal and ordinal arithmetic in ZF;
  2468 
  2469 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2470 types;
  2471 
  2472 
  2473 $Id$