NEWS
author ballarin
Tue Sep 30 15:07:38 2003 +0200 (2003-09-30)
changeset 14211 7286c187596d
parent 14199 d3b8d972a488
child 14224 442c097c1437
permissions -rw-r--r--
Improvements to Isar/Locales: premises generated by "includes" elements
changed. Bugfix "unify_frozen".
     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   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    24     locales are no longer forced to write Isar proof scripts.
    25     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    26     emulations.
    27   - INCOMPATIBILITY: names of variables to be instantiated may no
    28     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    29     This is consistent with the instantiation attribute "where".
    30 
    31 * Locales:
    32   - Goal statements involving the context element "includes" no longer
    33     generate theorems with internal delta predicates (those ending on
    34     "_axioms") in the premise.
    35     Resolve particular premise with <locale>.intro to obtain old form.
    36   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    37     specification and "includes" elements in goal statement.
    38 
    39 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    40   (Isar) contexts.
    41 
    42 *** HOL ***
    43 
    44 * 'specification' command added, allowing for definition by
    45 specification.
    46 
    47 * SET-Protocol: formalization and verification of the SET protocol suite;
    48 
    49 
    50 New in Isabelle2003 (May 2003)
    51 --------------------------------
    52 
    53 *** General ***
    54 
    55 * Provers/simplifier:
    56 
    57   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    58     Assumptions are now subject to complete mutual simplification,
    59     not just from left to right. The simplifier now preserves
    60     the order of assumptions.
    61 
    62     Potential INCOMPATIBILITY:
    63 
    64     -- simp sometimes diverges where the old version did
    65        not, e.g. invoking simp on the goal
    66 
    67         [| P (f x); y = x; f x = f y |] ==> Q
    68 
    69        now gives rise to the infinite reduction sequence
    70 
    71         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    72 
    73        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    74        kind of problem.
    75 
    76     -- Tactics combining classical reasoner and simplification (such as auto)
    77        are also affected by this change, because many of them rely on
    78        simp. They may sometimes diverge as well or yield a different numbers
    79        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    80        in case of problems. Sometimes subsequent calls to the classical
    81        reasoner will fail because a preceeding call to the simplifier too
    82        eagerly simplified the goal, e.g. deleted redundant premises.
    83 
    84   - The simplifier trace now shows the names of the applied rewrite rules
    85 
    86   - You can limit the number of recursive invocations of the simplifier
    87     during conditional rewriting (where the simplifie tries to solve the
    88     conditions before applying the rewrite rule):
    89     ML "simp_depth_limit := n"
    90     where n is an integer. Thus you can force termination where previously
    91     the simplifier would diverge.
    92 
    93   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
    94 
    95   - No longer aborts on failed congruence proof.  Instead, the
    96     congruence is ignored.
    97 
    98 * Pure: New generic framework for extracting programs from constructive
    99   proofs. See HOL/Extraction.thy for an example instantiation, as well
   100   as HOL/Extraction for some case studies.
   101 
   102 * Pure: The main goal of the proof state is no longer shown by default, only
   103 the subgoals. This behaviour is controlled by a new flag.
   104    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   105 (ML: Proof.show_main_goal).
   106 
   107 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   108 rules whose conclusion matches subgoal 1:
   109       PG menu: Isabelle/Isar -> Show me -> matching rules
   110 The rules are ordered by how closely they match the subgoal.
   111 In particular, rules that solve a subgoal outright are displayed first
   112 (or rather last, the way they are printed).
   113 (ML: ProofGeneral.print_intros())
   114 
   115 * Pure: New flag trace_unify_fail causes unification to print
   116 diagnostic information (PG: in trace buffer) when it fails. This is
   117 useful for figuring out why single step proofs like rule, erule or
   118 assumption failed.
   119 
   120 * Pure: Locale specifications now produce predicate definitions
   121 according to the body of text (covering assumptions modulo local
   122 definitions); predicate "loc_axioms" covers newly introduced text,
   123 while "loc" is cumulative wrt. all included locale expressions; the
   124 latter view is presented only on export into the global theory
   125 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   126 on the old view without predicates;
   127 
   128 * Pure: predefined locales "var" and "struct" are useful for sharing
   129 parameters (as in CASL, for example); just specify something like
   130 ``var x + var y + struct M'' as import;
   131 
   132 * Pure: improved thms_containing: proper indexing of facts instead of
   133 raw theorems; check validity of results wrt. current name space;
   134 include local facts of proof configuration (also covers active
   135 locales), cover fixed variables in index; may use "_" in term
   136 specification; an optional limit for the number of printed facts may
   137 be given (the default is 40);
   138 
   139 * Pure: disallow duplicate fact bindings within new-style theory files
   140 (batch-mode only);
   141 
   142 * Provers: improved induct method: assumptions introduced by case
   143 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   144 the goal statement); "foo" still refers to all facts collectively;
   145 
   146 * Provers: the function blast.overloaded has been removed: all constants
   147 are regarded as potentially overloaded, which improves robustness in exchange
   148 for slight decrease in efficiency;
   149 
   150 * Provers/linorder: New generic prover for transitivity reasoning over
   151 linear orders.  Note: this prover is not efficient!
   152 
   153 * Isar: preview of problems to finish 'show' now produce an error
   154 rather than just a warning (in interactive mode);
   155 
   156 
   157 *** HOL ***
   158 
   159 * arith(_tac)
   160 
   161  - Produces a counter example if it cannot prove a goal.
   162    Note that the counter example may be spurious if the goal is not a formula
   163    of quantifier-free linear arithmetic.
   164    In ProofGeneral the counter example appears in the trace buffer.
   165 
   166  - Knows about div k and mod k where k is a numeral of type nat or int.
   167 
   168  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   169    linear arithmetic fails. This takes account of quantifiers and divisibility.
   170    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   171 
   172 * simp's arithmetic capabilities have been enhanced a bit: it now
   173 takes ~= in premises into account (by performing a case split);
   174 
   175 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   176 are distributed over a sum of terms;
   177 
   178 * New tactic "trans_tac" and method "trans" instantiate
   179 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   180 "<=", "<" and "="). 
   181 
   182 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   183 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   184 
   185 * 'typedef' command has new option "open" to suppress the set
   186 definition;
   187 
   188 * functions Min and Max on finite sets have been introduced (theory
   189 Finite_Set);
   190 
   191 * attribute [symmetric] now works for relations as well; it turns
   192 (x,y) : R^-1 into (y,x) : R, and vice versa;
   193 
   194 * induct over a !!-quantified statement (say !!x1..xn):
   195   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   196 
   197 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   198 %x. None. Warning: empty_def now refers to the previously hidden definition
   199 of the empty set.
   200 
   201 * Algebra: formalization of classical algebra.  Intended as base for
   202 any algebraic development in Isabelle.  Currently covers group theory
   203 (up to Sylow's theorem) and ring theory (Universal Property of
   204 Univariate Polynomials).  Contributions welcome;
   205 
   206 * GroupTheory: deleted, since its material has been moved to Algebra;
   207 
   208 * Complex: new directory of the complex numbers with numeric constants, 
   209 nonstandard complex numbers, and some complex analysis, standard and 
   210 nonstandard (Jacques Fleuriot);
   211 
   212 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   213 
   214 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   215 Fleuriot);
   216 
   217 * Real/HahnBanach: updated and adapted to locales;
   218 
   219 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   220 Gray and Kramer);
   221 
   222 * UNITY: added the Meier-Sanders theory of progress sets;
   223 
   224 * MicroJava: bytecode verifier and lightweight bytecode verifier
   225 as abstract algorithms, instantiated to the JVM;
   226 
   227 * Bali: Java source language formalization. Type system, operational
   228 semantics, axiomatic semantics. Supported language features:
   229 classes, interfaces, objects,virtual methods, static methods,
   230 static/instance fields, arrays, access modifiers, definite
   231 assignment, exceptions.
   232 
   233 
   234 *** ZF ***
   235 
   236 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   237 universe, etc.);
   238 
   239 * Main ZF: virtually all theories converted to new-style format;
   240 
   241 
   242 *** ML ***
   243 
   244 * Pure: Tactic.prove provides sane interface for internal proofs;
   245 omits the infamous "standard" operation, so this is more appropriate
   246 than prove_goalw_cterm in many situations (e.g. in simprocs);
   247 
   248 * Pure: improved error reporting of simprocs;
   249 
   250 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   251 up simprocs;
   252 
   253 
   254 *** Document preparation ***
   255 
   256 * uses \par instead of \\ for line breaks in theory text. This may
   257 shift some page breaks in large documents. To get the old behaviour
   258 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   259 
   260 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   261 other packages
   262 
   263 * \<euro> now needs package babel/greek instead of marvosym (which
   264 broke \Rightarrow)
   265 
   266 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   267 textcomp package)
   268 
   269 
   270 New in Isabelle2002 (March 2002)
   271 --------------------------------
   272 
   273 *** Document preparation ***
   274 
   275 * greatly simplified document preparation setup, including more
   276 graceful interpretation of isatool usedir -i/-d/-D options, and more
   277 instructive isatool mkdir; users should basically be able to get
   278 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   279 users may run a separate document processing stage manually like this:
   280 "isatool usedir -D output HOL Test && isatool document Test/output";
   281 
   282 * theory dependency graph may now be incorporated into documents;
   283 isatool usedir -g true will produce session_graph.eps/.pdf for use
   284 with \includegraphics of LaTeX;
   285 
   286 * proper spacing of consecutive markup elements, especially text
   287 blocks after section headings;
   288 
   289 * support bold style (for single symbols only), input syntax is like
   290 this: "\<^bold>\<alpha>" or "\<^bold>A";
   291 
   292 * \<bullet> is now output as bold \cdot by default, which looks much
   293 better in printed text;
   294 
   295 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   296 note that these symbols are currently unavailable in Proof General /
   297 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   298 
   299 * isatool latex no longer depends on changed TEXINPUTS, instead
   300 isatool document copies the Isabelle style files to the target
   301 location;
   302 
   303 
   304 *** Isar ***
   305 
   306 * Pure/Provers: improved proof by cases and induction;
   307   - 'case' command admits impromptu naming of parameters (such as
   308     "case (Suc n)");
   309   - 'induct' method divinates rule instantiation from the inductive
   310     claim; no longer requires excessive ?P bindings for proper
   311     instantiation of cases;
   312   - 'induct' method properly enumerates all possibilities of set/type
   313     rules; as a consequence facts may be also passed through *type*
   314     rules without further ado;
   315   - 'induct' method now derives symbolic cases from the *rulified*
   316     rule (before it used to rulify cases stemming from the internal
   317     atomized version); this means that the context of a non-atomic
   318     statement becomes is included in the hypothesis, avoiding the
   319     slightly cumbersome show "PROP ?case" form;
   320   - 'induct' may now use elim-style induction rules without chaining
   321     facts, using ``missing'' premises from the goal state; this allows
   322     rules stemming from inductive sets to be applied in unstructured
   323     scripts, while still benefitting from proper handling of non-atomic
   324     statements; NB: major inductive premises need to be put first, all
   325     the rest of the goal is passed through the induction;
   326   - 'induct' proper support for mutual induction involving non-atomic
   327     rule statements (uses the new concept of simultaneous goals, see
   328     below);
   329   - append all possible rule selections, but only use the first
   330     success (no backtracking);
   331   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   332   - undeclared rule case names default to numbers 1, 2, 3, ...;
   333   - added 'print_induct_rules' (covered by help item in recent Proof
   334     General versions);
   335   - moved induct/cases attributes to Pure, methods to Provers;
   336   - generic method setup instantiated for FOL and HOL;
   337 
   338 * Pure: support multiple simultaneous goal statements, for example
   339 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   340 meta-level mechanism, this acts as if several individual goals had
   341 been stated separately; in particular common proof methods need to be
   342 repeated in order to cover all claims; note that a single elimination
   343 step is *not* sufficient to establish the two conjunctions, so this
   344 fails:
   345 
   346   assume "A & B" then have A and B ..   (*".." fails*)
   347 
   348 better use "obtain" in situations as above; alternative refer to
   349 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   350 
   351 * Pure: proper integration with ``locales''; unlike the original
   352 version by Florian Kammüller, Isar locales package high-level proof
   353 contexts rather than raw logical ones (e.g. we admit to include
   354 attributes everywhere); operations on locales include merge and
   355 rename; support for implicit arguments (``structures''); simultaneous
   356 type-inference over imports and text; see also HOL/ex/Locales.thy for
   357 some examples;
   358 
   359 * Pure: the following commands have been ``localized'', supporting a
   360 target locale specification "(in name)": 'lemma', 'theorem',
   361 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   362 stored both within the locale and at the theory level (exported and
   363 qualified by the locale name);
   364 
   365 * Pure: theory goals may now be specified in ``long'' form, with
   366 ad-hoc contexts consisting of arbitrary locale elements. for example
   367 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   368 definitions may be given, too); the result is a meta-level rule with
   369 the context elements being discharged in the obvious way;
   370 
   371 * Pure: new proof command 'using' allows to augment currently used
   372 facts after a goal statement ('using' is syntactically analogous to
   373 'apply', but acts on the goal's facts only); this allows chained facts
   374 to be separated into parts given before and after a claim, as in
   375 ``from a and b have C using d and e <proof>'';
   376 
   377 * Pure: renamed "antecedent" case to "rule_context";
   378 
   379 * Pure: new 'judgment' command records explicit information about the
   380 object-logic embedding (used by several tools internally); no longer
   381 use hard-wired "Trueprop";
   382 
   383 * Pure: added 'corollary' command;
   384 
   385 * Pure: fixed 'token_translation' command;
   386 
   387 * Pure: removed obsolete 'exported' attribute;
   388 
   389 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   390 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   391 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   392 
   393 * Pure: method 'atomize' presents local goal premises as object-level
   394 statements (atomic meta-level propositions); setup controlled via
   395 rewrite rules declarations of 'atomize' attribute; example
   396 application: 'induct' method with proper rule statements in improper
   397 proof *scripts*;
   398 
   399 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   400 now consider the syntactic context of assumptions, giving a better
   401 chance to get type-inference of the arguments right (this is
   402 especially important for locales);
   403 
   404 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   405 mode;
   406 
   407 * Pure/obtain: the formal conclusion "thesis", being marked as
   408 ``internal'', may no longer be reference directly in the text;
   409 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   410 situations;
   411 
   412 * Pure: generic 'sym' attribute which declares a rule both as pure
   413 'elim?' and for the 'symmetric' operation;
   414 
   415 * Pure: marginal comments ``--'' may now occur just anywhere in the
   416 text; the fixed correlation with particular command syntax has been
   417 discontinued;
   418 
   419 * Pure: new method 'rules' is particularly well-suited for proof
   420 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   421 but often produces more compact proof terms with less detours;
   422 
   423 * Pure/Provers/classical: simplified integration with pure rule
   424 attributes and methods; the classical "intro?/elim?/dest?"
   425 declarations coincide with the pure ones; the "rule" method no longer
   426 includes classically swapped intros; "intro" and "elim" methods no
   427 longer pick rules from the context; also got rid of ML declarations
   428 AddXIs/AddXEs/AddXDs; all of this has some potential for
   429 INCOMPATIBILITY;
   430 
   431 * Provers/classical: attribute 'swapped' produces classical inversions
   432 of introduction rules;
   433 
   434 * Provers/simplifier: 'simplified' attribute may refer to explicit
   435 rules instead of full simplifier context; 'iff' attribute handles
   436 conditional rules;
   437 
   438 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   439 
   440 * HOL: 'recdef' now fails on unfinished automated proofs, use
   441 "(permissive)" option to recover old behavior;
   442 
   443 * HOL: 'inductive' no longer features separate (collective) attributes
   444 for 'intros' (was found too confusing);
   445 
   446 * HOL: properly declared induction rules less_induct and
   447 wf_induct_rule;
   448 
   449 
   450 *** HOL ***
   451 
   452 * HOL: moved over to sane numeral syntax; the new policy is as
   453 follows:
   454 
   455   - 0 and 1 are polymorphic constants, which are defined on any
   456   numeric type (nat, int, real etc.);
   457 
   458   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   459   binary representation internally;
   460 
   461   - type nat has special constructor Suc, and generally prefers Suc 0
   462   over 1::nat and Suc (Suc 0) over 2::nat;
   463 
   464 This change may cause significant problems of INCOMPATIBILITY; here
   465 are some hints on converting existing sources:
   466 
   467   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   468   entities, so expressions involving "-" (unary or binary minus) need
   469   to be spaced properly;
   470 
   471   - existing occurrences of "1" may need to be constraint "1::nat" or
   472   even replaced by Suc 0; similar for old "2";
   473 
   474   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   475 
   476   - remove all special provisions on numerals in proofs;
   477 
   478 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   479 representation (depends on bin_arith_simps in the default context);
   480 
   481 * HOL: symbolic syntax for x^2 (numeral 2);
   482 
   483 * HOL: the class of all HOL types is now called "type" rather than
   484 "term"; INCOMPATIBILITY, need to adapt references to this type class
   485 in axclass/classes, instance/arities, and (usually rare) occurrences
   486 in typings (of consts etc.); internally the class is called
   487 "HOL.type", ML programs should refer to HOLogic.typeS;
   488 
   489 * HOL/record package improvements:
   490   - new derived operations "fields" to build a partial record section,
   491     "extend" to promote a fixed record to a record scheme, and
   492     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   493     declared as simp by default;
   494   - shared operations ("more", "fields", etc.) now need to be always
   495     qualified) --- potential INCOMPATIBILITY;
   496   - removed "make_scheme" operations (use "make" with "extend") --
   497     INCOMPATIBILITY;
   498   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   499   - provides cases/induct rules for use with corresponding Isar
   500     methods (for concrete records, record schemes, concrete more
   501     parts, and schematic more parts -- in that order);
   502   - internal definitions directly based on a light-weight abstract
   503     theory of product types over typedef rather than datatype;
   504 
   505 * HOL: generic code generator for generating executable ML code from
   506 specifications; specific support for HOL constructs such as inductive
   507 datatypes and sets, as well as recursive functions; can be invoked
   508 via 'generate_code' theory section;
   509 
   510 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   511 
   512 * HOL: consolidated and renamed several theories.  In particular:
   513 	Ord.thy has been absorbed into HOL.thy
   514 	String.thy has been absorbed into List.thy
   515  
   516 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   517 (beware of argument permutation!);
   518 
   519 * HOL: linorder_less_split superseded by linorder_cases;
   520 
   521 * HOL/List: "nodups" renamed to "distinct";
   522 
   523 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   524 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   525   - Ex_def has changed, now need to use some_eq_ex
   526 
   527 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   528 in this (rare) case use:
   529 
   530   delSWrapper "split_all_tac"
   531   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   532 
   533 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   534 MAY FAIL;
   535 
   536 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   537 Isabelle's type classes, ^ on functions and relations has too general
   538 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   539 necessary to attach explicit type constraints;
   540 
   541 * HOL/Relation: the prefix name of the infix "O" has been changed from
   542 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   543 renamed accordingly (eg "compI" -> "rel_compI").
   544 
   545 * HOL: syntax translations now work properly with numerals and records
   546 expressions;
   547 
   548 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   549 of "lam" -- INCOMPATIBILITY;
   550 
   551 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   552 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   553 renamed "Product_Type.unit";
   554 
   555 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   556 
   557 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   558 the "cases" method);
   559 
   560 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   561 Florian Kammüller);
   562 
   563 * HOL/IMP: updated and converted to new-style theory format; several
   564 parts turned into readable document, with proper Isar proof texts and
   565 some explanations (by Gerwin Klein);
   566 
   567 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   568 
   569 * HOL-Hyperreal is now a logic image;
   570 
   571 
   572 *** HOLCF ***
   573 
   574 * Isar: consts/constdefs supports mixfix syntax for continuous
   575 operations;
   576 
   577 * Isar: domain package adapted to new-style theory format, e.g. see
   578 HOLCF/ex/Dnat.thy;
   579 
   580 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   581 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   582 lift.induct_tac, always use UU instead of Undef;
   583 
   584 * HOLCF/IMP: updated and converted to new-style theory;
   585 
   586 
   587 *** ZF ***
   588 
   589 * Isar: proper integration of logic-specific tools and packages,
   590 including theory commands '(co)inductive', '(co)datatype',
   591 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   592 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   593 
   594 * theory Main no longer includes AC; for the Axiom of Choice, base
   595 your theory on Main_ZFC;
   596 
   597 * the integer library now covers quotients and remainders, with many
   598 laws relating division to addition, multiplication, etc.;
   599 
   600 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   601 typeless version of the formalism;
   602 
   603 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   604 format;
   605 
   606 * ZF/Induct: new directory for examples of inductive definitions,
   607 including theory Multiset for multiset orderings; converted to
   608 new-style theory format;
   609 
   610 * ZF: many new theorems about lists, ordinals, etc.;
   611 
   612 
   613 *** General ***
   614 
   615 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   616 variable proof controls level of detail: 0 = no proofs (only oracle
   617 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   618 also ref manual for further ML interfaces;
   619 
   620 * Pure/axclass: removed obsolete ML interface
   621 goal_subclass/goal_arity;
   622 
   623 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   624 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   625 separate tokens, so expressions involving minus need to be spaced
   626 properly;
   627 
   628 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   629 rather than "infixl" or "infixr";
   630 
   631 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   632 sort constraint specifications in type inference; e.g. "x::_::foo"
   633 ensures that the type of "x" is of sort "foo" (but not necessarily a
   634 type variable);
   635 
   636 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   637 control output of nested => (types); the default behavior is
   638 "type_brackets";
   639 
   640 * Pure/syntax: builtin parse translation for "_constify" turns valued
   641 tokens into AST constants;
   642 
   643 * Pure/syntax: prefer later declarations of translations and print
   644 translation functions; potential INCOMPATIBILITY: need to reverse
   645 multiple declarations for same syntax element constant;
   646 
   647 * Pure/show_hyps reset by default (in accordance to existing Isar
   648 practice);
   649 
   650 * Provers/classical: renamed addaltern to addafter, addSaltern to
   651 addSafter;
   652 
   653 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   654 as well;
   655 
   656 * system: tested support for MacOS X; should be able to get Isabelle +
   657 Proof General to work in a plain Terminal after installing Poly/ML
   658 (e.g. from the Isabelle distribution area) and GNU bash alone
   659 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   660 support requires further installations, e.g. from
   661 http://fink.sourceforge.net/);
   662 
   663 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   664 
   665 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   666 of 40 MB), cf. ML_OPTIONS;
   667 
   668 * system: Proof General keywords specification is now part of the
   669 Isabelle distribution (see etc/isar-keywords.el);
   670 
   671 * system: support for persistent Proof General sessions (refrain from
   672 outdating all loaded theories on startup); user may create writable
   673 logic images like this: ``isabelle -q HOL Test'';
   674 
   675 * system: smart selection of Isabelle process versus Isabelle
   676 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   677 run both "isabelle" and "Isabelle" even if file names are badly
   678 damaged (executable inspects the case of the first letter of its own
   679 name); added separate "isabelle-process" and "isabelle-interface";
   680 
   681 * system: refrain from any attempt at filtering input streams; no
   682 longer support ``8bit'' encoding of old isabelle font, instead proper
   683 iso-latin characters may now be used; the related isatools
   684 "symbolinput" and "nonascii" have disappeared as well;
   685 
   686 * system: removed old "xterm" interface (the print modes "xterm" and
   687 "xterm_color" are still available for direct use in a suitable
   688 terminal);
   689 
   690 
   691 
   692 New in Isabelle99-2 (February 2001)
   693 -----------------------------------
   694 
   695 *** Overview of INCOMPATIBILITIES ***
   696 
   697 * HOL: please note that theories in the Library and elsewhere often use the
   698 new-style (Isar) format; to refer to their theorems in an ML script you must
   699 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   700 
   701 * HOL: inductive package no longer splits induction rule aggressively,
   702 but only as far as specified by the introductions given; the old
   703 format may be recovered via ML function complete_split_rule or attribute
   704 'split_rule (complete)';
   705 
   706 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   707 gfp_Tarski to gfp_unfold;
   708 
   709 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   710 
   711 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   712 relation); infix "^^" has been renamed "``"; infix "``" has been
   713 renamed "`"; "univalent" has been renamed "single_valued";
   714 
   715 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   716 operation;
   717 
   718 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   719 
   720 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   721 
   722 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   723 consequence, it is no longer monotonic wrt. the local goal context
   724 (which is now passed through the inductive cases);
   725 
   726 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   727 \<gg> to \<ggreater>;
   728 
   729 
   730 *** Document preparation ***
   731 
   732 * \isabellestyle{NAME} selects version of Isabelle output (currently
   733 available: are "it" for near math-mode best-style output, "sl" for
   734 slanted text style, and "tt" for plain type-writer; if no
   735 \isabellestyle command is given, output is according to slanted
   736 type-writer);
   737 
   738 * support sub/super scripts (for single symbols only), input syntax is
   739 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   740 
   741 * some more standard symbols; see Appendix A of the system manual for
   742 the complete list of symbols defined in isabellesym.sty;
   743 
   744 * improved isabelle style files; more abstract symbol implementation
   745 (should now use \isamath{...} and \isatext{...} in custom symbol
   746 definitions);
   747 
   748 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   749 state; Note that presentation of goal states does not conform to
   750 actual human-readable proof documents.  Please do not include goal
   751 states into document output unless you really know what you are doing!
   752 
   753 * proper indentation of antiquoted output with proportional LaTeX
   754 fonts;
   755 
   756 * no_document ML operator temporarily disables LaTeX document
   757 generation;
   758 
   759 * isatool unsymbolize tunes sources for plain ASCII communication;
   760 
   761 
   762 *** Isar ***
   763 
   764 * Pure: Isar now suffers initial goal statements to contain unbound
   765 schematic variables (this does not conform to actual readable proof
   766 documents, due to unpredictable outcome and non-compositional proof
   767 checking); users who know what they are doing may use schematic goals
   768 for Prolog-style synthesis of proven results;
   769 
   770 * Pure: assumption method (an implicit finishing) now handles actual
   771 rules as well;
   772 
   773 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   774 initial goal, declare "that" only as Pure intro (only for single
   775 steps); the "that" rule assumption may now be involved in implicit
   776 finishing, thus ".." becomes a feasible for trivial obtains;
   777 
   778 * Pure: default proof step now includes 'intro_classes'; thus trivial
   779 instance proofs may be performed by "..";
   780 
   781 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   782 statements as well;
   783 
   784 * Pure: more robust selection of calculational rules;
   785 
   786 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   787 rule (as well as the assumption rule);
   788 
   789 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   790 lemmas, using the graph browser tool;
   791 
   792 * Pure: predict failure of "show" in interactive mode;
   793 
   794 * Pure: 'thms_containing' now takes actual terms as arguments;
   795 
   796 * HOL: improved method 'induct' --- now handles non-atomic goals
   797 (potential INCOMPATIBILITY); tuned error handling;
   798 
   799 * HOL: cases and induct rules now provide explicit hints about the
   800 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   801 any remaining facts are inserted into the goal verbatim;
   802 
   803 * HOL: local contexts (aka cases) may now contain term bindings as
   804 well; the 'cases' and 'induct' methods new provide a ?case binding for
   805 the result to be shown in each case;
   806 
   807 * HOL: added 'recdef_tc' command;
   808 
   809 * isatool convert assists in eliminating legacy ML scripts;
   810 
   811 
   812 *** HOL ***
   813 
   814 * HOL/Library: a collection of generic theories to be used together
   815 with main HOL; the theory loader path already includes this directory
   816 by default; the following existing theories have been moved here:
   817 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   818 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   819 
   820 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   821 modelling and verification task performed in Isabelle/HOL +
   822 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   823 
   824 * HOL/Algebra: special summation operator SUM no longer exists, it has
   825 been replaced by setsum; infix 'assoc' now has priority 50 (like
   826 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   827 'domain', this makes the theory consistent with mathematical
   828 literature;
   829 
   830 * HOL basics: added overloaded operations "inverse" and "divide"
   831 (infix "/"), syntax for generic "abs" operation, generic summation
   832 operator \<Sum>;
   833 
   834 * HOL/typedef: simplified package, provide more useful rules (see also
   835 HOL/subset.thy);
   836 
   837 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   838 now expressed as a proper nested rule (old-style tactic scripts may
   839 require atomize_strip_tac to cope with non-atomic premises);
   840 
   841 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   842 to "split_conv" (old name still available for compatibility);
   843 
   844 * HOL: improved concrete syntax for strings (e.g. allows translation
   845 rules with string literals);
   846 
   847 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   848  and Fleuriot's mechanization of analysis, including the transcendental
   849  functions for the reals;
   850 
   851 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   852 
   853 
   854 *** CTT ***
   855 
   856 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   857 "lam" is displayed as TWO lambda-symbols
   858 
   859 * CTT: theory Main now available, containing everything (that is, Bool
   860 and Arith);
   861 
   862 
   863 *** General ***
   864 
   865 * Pure: the Simplifier has been implemented properly as a derived rule
   866 outside of the actual kernel (at last!); the overall performance
   867 penalty in practical applications is about 50%, while reliability of
   868 the Isabelle inference kernel has been greatly improved;
   869 
   870 * print modes "brackets" and "no_brackets" control output of nested =>
   871 (types) and ==> (props); the default behaviour is "brackets";
   872 
   873 * Provers: fast_tac (and friends) now handle actual object-logic rules
   874 as assumptions as well;
   875 
   876 * system: support Poly/ML 4.0;
   877 
   878 * system: isatool install handles KDE version 1 or 2;
   879 
   880 
   881 
   882 New in Isabelle99-1 (October 2000)
   883 ----------------------------------
   884 
   885 *** Overview of INCOMPATIBILITIES ***
   886 
   887 * HOL: simplification of natural numbers is much changed; to partly
   888 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   889 issue the following ML commands:
   890 
   891   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   892   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   893 
   894 * HOL: simplification no longer dives into case-expressions; this is
   895 controlled by "t.weak_case_cong" for each datatype t;
   896 
   897 * HOL: nat_less_induct renamed to less_induct;
   898 
   899 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   900 fixsome to patch .thy and .ML sources automatically;
   901 
   902   select_equality  -> some_equality
   903   select_eq_Ex     -> some_eq_ex
   904   selectI2EX       -> someI2_ex
   905   selectI2         -> someI2
   906   selectI          -> someI
   907   select1_equality -> some1_equality
   908   Eps_sym_eq       -> some_sym_eq_trivial
   909   Eps_eq           -> some_eq_trivial
   910 
   911 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   912 
   913 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   914 instead);
   915 
   916 * HOL: the recursion equations generated by 'recdef' are now called
   917 f.simps instead of f.rules;
   918 
   919 * HOL: qed_spec_mp now also handles bounded ALL as well;
   920 
   921 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   922 sometimes be needed;
   923 
   924 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   925 
   926 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   927 
   928 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   929 product is now "<*>" instead of "Times"; the lexicographic product is
   930 now "<*lex*>" instead of "**";
   931 
   932 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   933 of main HOL, but was unused); better use HOL's datatype package;
   934 
   935 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   936 the old syntax may be recovered as follows:
   937 
   938   syntax (symbols)
   939     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   940       (infixl "\\<oplus>" 100)
   941 
   942 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   943 
   944 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   945 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   946 internally;
   947 
   948 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   949 changed from A/r to A//r;
   950 
   951 * ZF: new treatment of arithmetic (nat & int) may break some old
   952 proofs;
   953 
   954 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   955 rulify -> rule_format, elimify -> elim_format, ...);
   956 
   957 * Isar/Provers: intro/elim/dest attributes changed; renamed
   958 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   959 should have to change intro!! to intro? only); replaced "delrule" by
   960 "rule del";
   961 
   962 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   963 
   964 * Provers: strengthened force_tac by using new first_best_tac;
   965 
   966 * LaTeX document preparation: several changes of isabelle.sty (see
   967 lib/texinputs);
   968 
   969 
   970 *** Document preparation ***
   971 
   972 * formal comments (text blocks etc.) in new-style theories may now
   973 contain antiquotations of thm/prop/term/typ/text to be presented
   974 according to latex print mode; concrete syntax is like this:
   975 @{term[show_types] "f(x) = a + x"};
   976 
   977 * isatool mkdir provides easy setup of Isabelle session directories,
   978 including proper document sources;
   979 
   980 * generated LaTeX sources are now deleted after successful run
   981 (isatool document -c); may retain a copy somewhere else via -D option
   982 of isatool usedir;
   983 
   984 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   985 style files, achieving self-contained LaTeX sources and simplifying
   986 LaTeX debugging;
   987 
   988 * old-style theories now produce (crude) LaTeX output as well;
   989 
   990 * browser info session directories are now self-contained (may be put
   991 on WWW server seperately); improved graphs of nested sessions; removed
   992 graph for 'all sessions';
   993 
   994 * several improvements in isabelle style files; \isabellestyle{it}
   995 produces fake math mode output; \isamarkupheader is now \section by
   996 default; see lib/texinputs/isabelle.sty etc.;
   997 
   998 
   999 *** Isar ***
  1000 
  1001 * Isar/Pure: local results and corresponding term bindings are now
  1002 subject to Hindley-Milner polymorphism (similar to ML); this
  1003 accommodates incremental type-inference very nicely;
  1004 
  1005 * Isar/Pure: new derived language element 'obtain' supports
  1006 generalized existence reasoning;
  1007 
  1008 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1009 support accumulation of results, without applying any rules yet;
  1010 useful to collect intermediate results without explicit name
  1011 references, and for use with transitivity rules with more than 2
  1012 premises;
  1013 
  1014 * Isar/Pure: scalable support for case-analysis type proofs: new
  1015 'case' language element refers to local contexts symbolically, as
  1016 produced by certain proof methods; internally, case names are attached
  1017 to theorems as "tags";
  1018 
  1019 * Isar/Pure: theory command 'hide' removes declarations from
  1020 class/type/const name spaces;
  1021 
  1022 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1023 indicate potential overloading;
  1024 
  1025 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1026 
  1027 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1028 "{a,b,c}" instead of {a,b,c};
  1029 
  1030 * Isar/Pure now provides its own version of intro/elim/dest
  1031 attributes; useful for building new logics, but beware of confusion
  1032 with the version in Provers/classical;
  1033 
  1034 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1035 case name 'antecedent';
  1036 
  1037 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1038 to the current context is now done automatically);
  1039 
  1040 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1041 for definining proof methods in ML;
  1042 
  1043 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1044 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1045 most cases, one should have to change intro!! to intro? only);
  1046 replaced "delrule" by "rule del";
  1047 
  1048 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1049 'symmetric' attribute (the latter supercedes [RS sym]);
  1050 
  1051 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1052 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1053 well (including splits);
  1054 
  1055 * Isar/Provers: Simplifier and Classical methods now support all kind
  1056 of modifiers used in the past, including 'cong', 'iff', etc.
  1057 
  1058 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1059 of Simplifier and Classical reasoner);
  1060 
  1061 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1062 now support named cases; major packages (inductive, datatype, primrec,
  1063 recdef) support case names and properly name parameters;
  1064 
  1065 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1066 monotonicity conditions are extracted to be proven at end of
  1067 calculations;
  1068 
  1069 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1070 method anyway;
  1071 
  1072 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1073 split_if split_if_asm; datatype package provides theorems foo.splits =
  1074 foo.split foo.split_asm for each datatype;
  1075 
  1076 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1077 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1078 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1079 use "(cases (simplified))" method in proper proof texts);
  1080 
  1081 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1082 
  1083 * Isar: names of theorems etc. may be natural numbers as well;
  1084 
  1085 * Isar: 'pr' command: optional arguments for goals_limit and
  1086 ProofContext.prems_limit; no longer prints theory contexts, but only
  1087 proof states;
  1088 
  1089 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1090 additional print modes to be specified; e.g. "pr(latex)" will print
  1091 proof state according to the Isabelle LaTeX style;
  1092 
  1093 * Isar: improved support for emulating tactic scripts, including proof
  1094 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1095 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1096 (for HOL datatypes);
  1097 
  1098 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1099 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1100 'proof method scripts' have to be in depth-first order;
  1101 
  1102 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1103 
  1104 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1105 should instead use individual commands for printing items
  1106 (print_commands, print_methods etc.);
  1107 
  1108 * Isar: added 'nothing' --- the empty list of theorems;
  1109 
  1110 
  1111 *** HOL ***
  1112 
  1113 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1114 corresponding virtual machine and a specification of its bytecode
  1115 verifier and a lightweight bytecode verifier, including proofs of
  1116 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1117 Cornelia Pusch (see also the homepage of project Bali at
  1118 http://isabelle.in.tum.de/Bali/);
  1119 
  1120 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1121 Clemens Ballarin;
  1122 
  1123 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1124 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1125 Rasmussen;
  1126 
  1127 * HOL/Lattice: fundamental concepts of lattice theory and order
  1128 structures, including duals, properties of bounds versus algebraic
  1129 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1130 Theorem for complete lattices etc.; may also serve as a demonstration
  1131 for abstract algebraic reasoning using axiomatic type classes, and
  1132 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1133 
  1134 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1135 von Oheimb;
  1136 
  1137 * HOL/IMPP: extension of IMP with local variables and mutually
  1138 recursive procedures, by David von Oheimb;
  1139 
  1140 * HOL/Lambda: converted into new-style theory and document;
  1141 
  1142 * HOL/ex/Multiquote: example of multiple nested quotations and
  1143 anti-quotations -- basically a generalized version of de-Bruijn
  1144 representation; very useful in avoiding lifting of operations;
  1145 
  1146 * HOL/record: added general record equality rule to simpset; fixed
  1147 select-update simplification procedure to handle extended records as
  1148 well; admit "r" as field name;
  1149 
  1150 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1151 other numeric types and also as the identity of groups, rings, etc.;
  1152 
  1153 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1154 Types nat and int belong to this axclass;
  1155 
  1156 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1157    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1158    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1159   two terms #m*u and #n*u are replaced by #(m+n)*u
  1160     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1161   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1162     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1163 
  1164 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1165 powerful prover for predicate logic but knows nothing of clasets; see
  1166 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1167 
  1168 * HOL: new version of "case_tac" subsumes both boolean case split and
  1169 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1170 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1171 
  1172 * HOL: simplification no longer dives into case-expressions: only the
  1173 selector expression is simplified, but not the remaining arms; to
  1174 enable full simplification of case-expressions for datatype t, you may
  1175 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1176 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1177 
  1178 * HOL/recdef: the recursion equations generated by 'recdef' for
  1179 function 'f' are now called f.simps instead of f.rules; if all
  1180 termination conditions are proved automatically, these simplification
  1181 rules are added to the simpset, as in primrec; rules may be named
  1182 individually as well, resulting in a separate list of theorems for
  1183 each equation;
  1184 
  1185 * HOL/While is a new theory that provides a while-combinator. It
  1186 permits the definition of tail-recursive functions without the
  1187 provision of a termination measure. The latter is necessary once the
  1188 invariant proof rule for while is applied.
  1189 
  1190 * HOL: new (overloaded) notation for the set of elements below/above
  1191 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1192 
  1193 * HOL: theorems impI, allI, ballI bound as "strip";
  1194 
  1195 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1196 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1197 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1198 
  1199 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1200 
  1201 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1202 main HOL, but was unused);
  1203 
  1204 * HOL: fewer consts declared as global (e.g. have to refer to
  1205 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1206 
  1207 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1208 in case of overlap with user translations (e.g. judgements over
  1209 tuples); (note that the underlying logical represenation is still
  1210 bogus);
  1211 
  1212 
  1213 *** ZF ***
  1214 
  1215 * ZF: simplification automatically cancels common terms in arithmetic
  1216 expressions over nat and int;
  1217 
  1218 * ZF: new treatment of nat to minimize type-checking: all operators
  1219 coerce their operands to a natural number using the function natify,
  1220 making the algebraic laws unconditional;
  1221 
  1222 * ZF: as above, for int: operators coerce their operands to an integer
  1223 using the function intify;
  1224 
  1225 * ZF: the integer library now contains many of the usual laws for the
  1226 orderings, including $<=, and monotonicity laws for $+ and $*;
  1227 
  1228 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1229 simplification;
  1230 
  1231 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1232 to the simplifier and classical reasoner simultaneously;
  1233 
  1234 
  1235 *** General ***
  1236 
  1237 * Provers: blast_tac now handles actual object-logic rules as
  1238 assumptions; note that auto_tac uses blast_tac internally as well;
  1239 
  1240 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1241 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1242 
  1243 * Provers: delrules now handles destruct rules as well (no longer need
  1244 explicit make_elim);
  1245 
  1246 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1247   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1248 use instead the strong form,
  1249   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1250 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1251 from destruct-rules;
  1252 
  1253 * Provers: Simplifier.easy_setup provides a fast path to basic
  1254 Simplifier setup for new object-logics;
  1255 
  1256 * Pure: AST translation rules no longer require constant head on LHS;
  1257 
  1258 * Pure: improved name spaces: ambiguous output is qualified; support
  1259 for hiding of names;
  1260 
  1261 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1262 XSYMBOL_HOME; no longer need to do manual configuration in most
  1263 situations;
  1264 
  1265 * system: compression of ML heaps images may now be controlled via -c
  1266 option of isabelle and isatool usedir (currently only observed by
  1267 Poly/ML);
  1268 
  1269 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1270 useful for remote X11);
  1271 
  1272 * system: provide TAGS file for Isabelle sources;
  1273 
  1274 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1275 order;
  1276 
  1277 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1278 timing flag supersedes proof_timing and Toplevel.trace;
  1279 
  1280 * ML: new combinators |>> and |>>> for incremental transformations
  1281 with secondary results (e.g. certain theory extensions):
  1282 
  1283 * ML: PureThy.add_defs gets additional argument to indicate potential
  1284 overloading (usually false);
  1285 
  1286 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1287 results;
  1288 
  1289 
  1290 
  1291 New in Isabelle99 (October 1999)
  1292 --------------------------------
  1293 
  1294 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1295 
  1296 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1297 are no longer simplified.  (This allows the simplifier to unfold recursive
  1298 functional programs.)  To restore the old behaviour, declare
  1299 
  1300     Delcongs [if_weak_cong];
  1301 
  1302 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1303 complement;
  1304 
  1305 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1306 
  1307 * HOL/datatype: mutual_induct_tac no longer exists --
  1308   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1309 
  1310 * HOL/typedef: fixed type inference for representing set; type
  1311 arguments now have to occur explicitly on the rhs as type constraints;
  1312 
  1313 * ZF: The con_defs part of an inductive definition may no longer refer
  1314 to constants declared in the same theory;
  1315 
  1316 * HOL, ZF: the function mk_cases, generated by the inductive
  1317 definition package, has lost an argument.  To simplify its result, it
  1318 uses the default simpset instead of a supplied list of theorems.
  1319 
  1320 * HOL/List: the constructors of type list are now Nil and Cons;
  1321 
  1322 * Simplifier: the type of the infix ML functions
  1323         setSSolver addSSolver setSolver addSolver
  1324 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1325 for packaging solvers. A solver is created via
  1326         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1327 where the string argument is only a comment.
  1328 
  1329 
  1330 *** Proof tools ***
  1331 
  1332 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1333 decision procedure for linear arithmetic. Currently it is used for
  1334 types `nat', `int', and `real' in HOL (see below); it can, should and
  1335 will be instantiated for other types and logics as well.
  1336 
  1337 * The simplifier now accepts rewrite rules with flexible heads, eg
  1338      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1339   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1340   matching.
  1341 
  1342 
  1343 *** General ***
  1344 
  1345 * New Isabelle/Isar subsystem provides an alternative to traditional
  1346 tactical theorem proving; together with the ProofGeneral/isar user
  1347 interface it offers an interactive environment for developing human
  1348 readable proof documents (Isar == Intelligible semi-automated
  1349 reasoning); for further information see isatool doc isar-ref,
  1350 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1351 
  1352 * improved and simplified presentation of theories: better HTML markup
  1353 (including colors), graph views in several sizes; isatool usedir now
  1354 provides a proper interface for user theories (via -P option); actual
  1355 document preparation based on (PDF)LaTeX is available as well (for
  1356 new-style theories only); see isatool doc system for more information;
  1357 
  1358 * native support for Proof General, both for classic Isabelle and
  1359 Isabelle/Isar;
  1360 
  1361 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1362 using the graph browser tool;
  1363 
  1364 * Isabelle manuals now also available as PDF;
  1365 
  1366 * theory loader rewritten from scratch (may not be fully
  1367 bug-compatible); old loadpath variable has been replaced by show_path,
  1368 add_path, del_path, reset_path functions; new operations such as
  1369 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1370 isatool doc ref);
  1371 
  1372 * improved isatool install: option -k creates KDE application icon,
  1373 option -p DIR installs standalone binaries;
  1374 
  1375 * added ML_PLATFORM setting (useful for cross-platform installations);
  1376 more robust handling of platform specific ML images for SML/NJ;
  1377 
  1378 * the settings environment is now statically scoped, i.e. it is never
  1379 created again in sub-processes invoked from isabelle, isatool, or
  1380 Isabelle;
  1381 
  1382 * path element specification '~~' refers to '$ISABELLE_HOME';
  1383 
  1384 * in locales, the "assumes" and "defines" parts may be omitted if
  1385 empty;
  1386 
  1387 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1388 long arrows);
  1389 
  1390 * new print_mode "HTML";
  1391 
  1392 * new flag show_tags controls display of tags of theorems (which are
  1393 basically just comments that may be attached by some tools);
  1394 
  1395 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1396 mode and goal output format:
  1397 
  1398 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1399 244c244
  1400 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1401 ---
  1402 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1403 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1404 181c181
  1405 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1406 ---
  1407 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1408 
  1409 * function bind_thms stores lists of theorems (cf. bind_thm);
  1410 
  1411 * new shorthand tactics ftac, eatac, datac, fatac;
  1412 
  1413 * qed (and friends) now accept "" as result name; in that case the
  1414 theorem is not stored, but proper checks and presentation of the
  1415 result still apply;
  1416 
  1417 * theorem database now also indexes constants "Trueprop", "all",
  1418 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1419 
  1420 
  1421 *** HOL ***
  1422 
  1423 ** HOL arithmetic **
  1424 
  1425 * There are now decision procedures for linear arithmetic over nat and
  1426 int:
  1427 
  1428 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1429 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1430 are treated as atomic; subformulae not involving type `nat' or `int'
  1431 are ignored; quantified subformulae are ignored unless they are
  1432 positive universal or negative existential. The tactic has to be
  1433 invoked by hand and can be a little bit slow. In particular, the
  1434 running time is exponential in the number of occurrences of `min' and
  1435 `max', and `-' on `nat'.
  1436 
  1437 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1438 (negated) (in)equalities among the premises and the conclusion into
  1439 account (i.e. no compound formulae) and does not know about `min' and
  1440 `max', and `-' on `nat'. It is fast and is used automatically by the
  1441 simplifier.
  1442 
  1443 NB: At the moment, these decision procedures do not cope with mixed
  1444 nat/int formulae where the two parts interact, such as `m < n ==>
  1445 int(m) < int(n)'.
  1446 
  1447 * HOL/Numeral provides a generic theory of numerals (encoded
  1448 efficiently as bit strings); setup for types nat/int/real is in place;
  1449 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1450 int, existing theories and proof scripts may require a few additional
  1451 type constraints;
  1452 
  1453 * integer division and remainder can now be performed on constant
  1454 arguments;
  1455 
  1456 * many properties of integer multiplication, division and remainder
  1457 are now available;
  1458 
  1459 * An interface to the Stanford Validity Checker (SVC) is available through the
  1460 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1461 are proved automatically.  SVC must be installed separately, and its results
  1462 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1463 invocation of the underlying oracle).  For SVC see
  1464   http://verify.stanford.edu/SVC
  1465 
  1466 * IsaMakefile: the HOL-Real target now builds an actual image;
  1467 
  1468 
  1469 ** HOL misc **
  1470 
  1471 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1472 (in Isabelle/Isar) -- by Gertrud Bauer;
  1473 
  1474 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1475 analysis for assembly languages with subtypes;
  1476 
  1477 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1478 -- avoids syntactic ambiguities and treats state, transition, and
  1479 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1480 changed syntax and (many) tactics;
  1481 
  1482 * HOL/inductive: Now also handles more general introduction rules such
  1483   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1484   theorems are now maintained within the theory (maintained via the
  1485   "mono" attribute);
  1486 
  1487 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1488   (using function types) such as
  1489 
  1490   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1491 
  1492 * HOL/record: record_simproc (part of the default simpset) takes care
  1493 of selectors applied to updated records; record_split_tac is no longer
  1494 part of the default claset; update_defs may now be removed from the
  1495 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1496 
  1497   claset_ref () := claset() addSWrapper record_split_wrapper;
  1498   Delsimprocs [record_simproc]
  1499 
  1500 * HOL/typedef: fixed type inference for representing set; type
  1501 arguments now have to occur explicitly on the rhs as type constraints;
  1502 
  1503 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1504 names rather than an ML expression;
  1505 
  1506 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1507 supplied later.  Program schemes can be defined, such as
  1508     "While B C s = (if B s then While B C (C s) else s)"
  1509 where the well-founded relation can be chosen after B and C have been given.
  1510 
  1511 * HOL/List: the constructors of type list are now Nil and Cons;
  1512 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1513 course, ML tools referring to List.list.op # etc. have to be adapted;
  1514 
  1515 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1516 disabled by default; run isabelle with option -m HOL to get back to
  1517 the original Gordon/HOL-style output;
  1518 
  1519 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1520 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1521 
  1522 * HOL basic syntax simplified (more orthogonal): all variants of
  1523 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1524 Eps operator is provided as well: "SOME x. P[x]";
  1525 
  1526 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1527 
  1528 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1529 thus available for user theories;
  1530 
  1531 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1532 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1533 time;
  1534 
  1535 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1536 several times and then mp;
  1537 
  1538 
  1539 *** LK ***
  1540 
  1541 * the notation <<...>> is now available as a notation for sequences of
  1542 formulas;
  1543 
  1544 * the simplifier is now installed
  1545 
  1546 * the axiom system has been generalized (thanks to Soren Heilmann)
  1547 
  1548 * the classical reasoner now has a default rule database
  1549 
  1550 
  1551 *** ZF ***
  1552 
  1553 * new primrec section allows primitive recursive functions to be given
  1554 directly (as in HOL) over datatypes and the natural numbers;
  1555 
  1556 * new tactics induct_tac and exhaust_tac for induction (or case
  1557 analysis) over datatypes and the natural numbers;
  1558 
  1559 * the datatype declaration of type T now defines the recursor T_rec;
  1560 
  1561 * simplification automatically does freeness reasoning for datatype
  1562 constructors;
  1563 
  1564 * automatic type-inference, with AddTCs command to insert new
  1565 type-checking rules;
  1566 
  1567 * datatype introduction rules are now added as Safe Introduction rules
  1568 to the claset;
  1569 
  1570 * the syntax "if P then x else y" is now available in addition to
  1571 if(P,x,y);
  1572 
  1573 
  1574 *** Internal programming interfaces ***
  1575 
  1576 * tuned simplifier trace output; new flag debug_simp;
  1577 
  1578 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1579 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1580 
  1581 * AxClass.axclass_tac lost the theory argument;
  1582 
  1583 * tuned current_goals_markers semantics: begin / end goal avoids
  1584 printing empty lines;
  1585 
  1586 * removed prs and prs_fn hook, which was broken because it did not
  1587 include \n in its semantics, forcing writeln to add one
  1588 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1589 string -> unit if you really want to output text without newline;
  1590 
  1591 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1592 plain output, interface builders may have to enable 'isabelle_font'
  1593 mode to get Isabelle font glyphs as before;
  1594 
  1595 * refined token_translation interface; INCOMPATIBILITY: output length
  1596 now of type real instead of int;
  1597 
  1598 * theory loader actions may be traced via new ThyInfo.add_hook
  1599 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1600 your own database of information attached to *whole* theories -- as
  1601 opposed to intra-theory data slots offered via TheoryDataFun;
  1602 
  1603 * proper handling of dangling sort hypotheses (at last!);
  1604 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1605 extra sort hypotheses that can be witnessed from the type signature;
  1606 the force_strip_shyps flag is gone, any remaining shyps are simply
  1607 left in the theorem (with a warning issued by strip_shyps_warning);
  1608 
  1609 
  1610 
  1611 New in Isabelle98-1 (October 1998)
  1612 ----------------------------------
  1613 
  1614 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1615 
  1616 * several changes of automated proof tools;
  1617 
  1618 * HOL: major changes to the inductive and datatype packages, including
  1619 some minor incompatibilities of theory syntax;
  1620 
  1621 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1622 called `inj_on';
  1623 
  1624 * HOL: removed duplicate thms in Arith:
  1625   less_imp_add_less  should be replaced by  trans_less_add1
  1626   le_imp_add_le      should be replaced by  trans_le_add1
  1627 
  1628 * HOL: unary minus is now overloaded (new type constraints may be
  1629 required);
  1630 
  1631 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1632 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1633 now taken as an integer constant.
  1634 
  1635 * Pure: ML function 'theory_of' renamed to 'theory';
  1636 
  1637 
  1638 *** Proof tools ***
  1639 
  1640 * Simplifier:
  1641   1. Asm_full_simp_tac is now more aggressive.
  1642      1. It will sometimes reorient premises if that increases their power to
  1643         simplify.
  1644      2. It does no longer proceed strictly from left to right but may also
  1645         rotate premises to achieve further simplification.
  1646      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1647      old Asm_full_simp_tac in that it does not rotate premises.
  1648   2. The simplifier now knows a little bit about nat-arithmetic.
  1649 
  1650 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1651 allows for selected deletion of wrappers, by introduction of names for
  1652 wrapper functionals.  This implies that addbefore, addSbefore,
  1653 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1654 and that adding two tactics with the same name overwrites the first
  1655 one (emitting a warning).
  1656   type wrapper = (int -> tactic) -> (int -> tactic)
  1657   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1658   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1659   delWrapper, delSWrapper: claset *  string            -> claset
  1660   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1661 
  1662 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1663 semantics; addbefore now affects only the unsafe part of step_tac
  1664 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1665 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1666 by Force_tac;
  1667 
  1668 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1669 compWrapper; added safe wrapper (and access functions for it);
  1670 
  1671 * HOL/split_all_tac is now much faster and fails if there is nothing
  1672 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1673 and the names of the automatically generated variables have changed.
  1674 split_all_tac has moved within claset() from unsafe wrappers to safe
  1675 wrappers, which means that !!-bound variables are split much more
  1676 aggressively, and safe_tac and clarify_tac now split such variables.
  1677 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1678 Note: the same holds for record_split_tac, which does the job of
  1679 split_all_tac for record fields.
  1680 
  1681 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1682 permanently to the default simpset using Addsplits just like
  1683 Addsimps. They can be removed via Delsplits just like
  1684 Delsimps. Lower-case versions are also available.
  1685 
  1686 * HOL/Simplifier: The rule split_if is now part of the default
  1687 simpset. This means that the simplifier will eliminate all occurrences
  1688 of if-then-else in the conclusion of a goal. To prevent this, you can
  1689 either remove split_if completely from the default simpset by
  1690 `Delsplits [split_if]' or remove it in a specific call of the
  1691 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1692 other case splitting rules to/from the default simpset: every datatype
  1693 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1694 t is the name of the datatype).
  1695 
  1696 * Classical reasoner / Simplifier combination: new force_tac (and
  1697 derivatives Force_tac, force) combines rewriting and classical
  1698 reasoning (and whatever other tools) similarly to auto_tac, but is
  1699 aimed to solve the given subgoal completely.
  1700 
  1701 
  1702 *** General ***
  1703 
  1704 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1705 and `goalw': the theory is no longer needed as an explicit argument -
  1706 the current theory context is used; assumptions are no longer returned
  1707 at the ML-level unless one of them starts with ==> or !!; it is
  1708 recommended to convert to these new commands using isatool fixgoal
  1709 (backup your sources first!);
  1710 
  1711 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1712 the current theory context, and 'theory' to lookup stored theories;
  1713 
  1714 * new theory section 'locale' for declaring constants, assumptions and
  1715 definitions that have local scope;
  1716 
  1717 * new theory section 'nonterminals' for purely syntactic types;
  1718 
  1719 * new theory section 'setup' for generic ML setup functions
  1720 (e.g. package initialization);
  1721 
  1722 * the distribution now includes Isabelle icons: see
  1723 lib/logo/isabelle-{small,tiny}.xpm;
  1724 
  1725 * isatool install - install binaries with absolute references to
  1726 ISABELLE_HOME/bin;
  1727 
  1728 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1729 
  1730 * print mode 'emacs' reserved for Isamode;
  1731 
  1732 * support multiple print (ast) translations per constant name;
  1733 
  1734 * theorems involving oracles are now printed with a suffixed [!];
  1735 
  1736 
  1737 *** HOL ***
  1738 
  1739 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1740 
  1741 * HOL/inductive package reorganized and improved: now supports mutual
  1742 definitions such as
  1743 
  1744   inductive EVEN ODD
  1745     intrs
  1746       null "0 : EVEN"
  1747       oddI "n : EVEN ==> Suc n : ODD"
  1748       evenI "n : ODD ==> Suc n : EVEN"
  1749 
  1750 new theorem list "elims" contains an elimination rule for each of the
  1751 recursive sets; inductive definitions now handle disjunctive premises
  1752 correctly (also ZF);
  1753 
  1754 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1755 "mutual_induct" no longer exists - the induction rule is always
  1756 contained in "induct";
  1757 
  1758 
  1759 * HOL/datatype package re-implemented and greatly improved: now
  1760 supports mutually recursive datatypes such as
  1761 
  1762   datatype
  1763     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1764             | SUM ('a aexp) ('a aexp)
  1765             | DIFF ('a aexp) ('a aexp)
  1766             | NUM 'a
  1767   and
  1768     'a bexp = LESS ('a aexp) ('a aexp)
  1769             | AND ('a bexp) ('a bexp)
  1770             | OR ('a bexp) ('a bexp)
  1771 
  1772 as well as indirectly recursive datatypes such as
  1773 
  1774   datatype
  1775     ('a, 'b) term = Var 'a
  1776                   | App 'b ((('a, 'b) term) list)
  1777 
  1778 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1779 induction on mutually / indirectly recursive datatypes.
  1780 
  1781 Primrec equations are now stored in theory and can be accessed via
  1782 <function_name>.simps.
  1783 
  1784 INCOMPATIBILITIES:
  1785 
  1786   - Theories using datatypes must now have theory Datatype as an
  1787     ancestor.
  1788   - The specific <typename>.induct_tac no longer exists - use the
  1789     generic induct_tac instead.
  1790   - natE has been renamed to nat.exhaust - use exhaust_tac
  1791     instead of res_inst_tac ... natE. Note that the variable
  1792     names in nat.exhaust differ from the names in natE, this
  1793     may cause some "fragile" proofs to fail.
  1794   - The theorems split_<typename>_case and split_<typename>_case_asm
  1795     have been renamed to <typename>.split and <typename>.split_asm.
  1796   - Since default sorts of type variables are now handled correctly,
  1797     some datatype definitions may have to be annotated with explicit
  1798     sort constraints.
  1799   - Primrec definitions no longer require function name and type
  1800     of recursive argument.
  1801 
  1802 Consider using isatool fixdatatype to adapt your theories and proof
  1803 scripts to the new package (backup your sources first!).
  1804 
  1805 
  1806 * HOL/record package: considerably improved implementation; now
  1807 includes concrete syntax for record types, terms, updates; theorems
  1808 for surjective pairing and splitting !!-bound record variables; proof
  1809 support is as follows:
  1810 
  1811   1) standard conversions (selectors or updates applied to record
  1812 constructor terms) are part of the standard simpset;
  1813 
  1814   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1815 made part of standard simpset and claset via addIffs;
  1816 
  1817   3) a tactic for record field splitting (record_split_tac) is part of
  1818 the standard claset (addSWrapper);
  1819 
  1820 To get a better idea about these rules you may retrieve them via
  1821 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1822 the name of your record type.
  1823 
  1824 The split tactic 3) conceptually simplifies by the following rule:
  1825 
  1826   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1827 
  1828 Thus any record variable that is bound by meta-all will automatically
  1829 blow up into some record constructor term, consequently the
  1830 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1831 solve record problems automatically.
  1832 
  1833 
  1834 * reorganized the main HOL image: HOL/Integ and String loaded by
  1835 default; theory Main includes everything;
  1836 
  1837 * automatic simplification of integer sums and comparisons, using cancellation;
  1838 
  1839 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1840 
  1841 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1842 
  1843 * many new identities for unions, intersections, set difference, etc.;
  1844 
  1845 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1846 called split_if, split_split, split_sum_case and split_nat_case (to go
  1847 with add/delsplits);
  1848 
  1849 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1850 (?x::unit) = (); this is made part of the default simpset, which COULD
  1851 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1852 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1853 unit_abs_eta_conv is added in order to counter the effect of
  1854 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1855 %u.f();
  1856 
  1857 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1858 makes more sense);
  1859 
  1860 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1861   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1862   disjointness reasoning but breaking a few old proofs.
  1863 
  1864 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1865 to 'converse' from 'inverse' (for compatibility with ZF and some
  1866 literature);
  1867 
  1868 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1869 the well-founded relation;
  1870 
  1871 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1872     Compl A.  The "Compl" syntax remains available as input syntax for this
  1873     release ONLY.
  1874 
  1875 * HOL/Update: new theory of function updates:
  1876     f(a:=b) == %x. if x=a then b else f x
  1877 may also be iterated as in f(a:=b,c:=d,...);
  1878 
  1879 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1880 
  1881 * HOL/List:
  1882   - new function list_update written xs[i:=v] that updates the i-th
  1883     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1884   - new function `upt' written [i..j(] which generates the list
  1885     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1886     bound write [i..j], which is a shorthand for [i..j+1(].
  1887   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1888 
  1889 * HOL/Arith:
  1890   - removed 'pred' (predecessor) function;
  1891   - generalized some theorems about n-1;
  1892   - many new laws about "div" and "mod";
  1893   - new laws about greatest common divisors (see theory ex/Primes);
  1894 
  1895 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1896 instead of "inverse";
  1897 
  1898 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1899   of the multiset ordering;
  1900 
  1901 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1902   (not included by default);
  1903 
  1904 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1905 
  1906 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1907   programs, i.e. different program variables may have different types.
  1908 
  1909 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1910   [previously, this check worked only if the rewrite rule was unconditional]
  1911   Now rew can involve either definitions or equalities (either == or =).
  1912 
  1913 
  1914 *** ZF ***
  1915 
  1916 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1917   only the theorems proved on ZF.ML;
  1918 
  1919 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1920   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1921   disjointness reasoning but breaking a few old proofs.
  1922 
  1923 * ZF/Update: new theory of function updates
  1924     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1925   may also be iterated as in f(a:=b,c:=d,...);
  1926 
  1927 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1928 
  1929 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1930   [previously, this check worked only if the rewrite rule was unconditional]
  1931   Now rew can involve either definitions or equalities (either == or =).
  1932 
  1933 * case_tac provided for compatibility with HOL
  1934     (like the old excluded_middle_tac, but with subgoals swapped)
  1935 
  1936 
  1937 *** Internal programming interfaces ***
  1938 
  1939 * Pure: several new basic modules made available for general use, see
  1940 also src/Pure/README;
  1941 
  1942 * improved the theory data mechanism to support encapsulation (data
  1943 kind name replaced by private Object.kind, acting as authorization
  1944 key); new type-safe user interface via functor TheoryDataFun; generic
  1945 print_data function becomes basically useless;
  1946 
  1947 * removed global_names compatibility flag -- all theory declarations
  1948 are qualified by default;
  1949 
  1950 * module Pure/Syntax now offers quote / antiquote translation
  1951 functions (useful for Hoare logic etc. with implicit dependencies);
  1952 see HOL/ex/Antiquote for an example use;
  1953 
  1954 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1955 cterm -> thm;
  1956 
  1957 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1958 subgoal;
  1959 
  1960 * Display.print_goals function moved to Locale.print_goals;
  1961 
  1962 * standard print function for goals supports current_goals_markers
  1963 variable for marking begin of proof, end of proof, start of goal; the
  1964 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1965 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1966 for example;
  1967 
  1968 
  1969 
  1970 New in Isabelle98 (January 1998)
  1971 --------------------------------
  1972 
  1973 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1974 
  1975 * changed lexical syntax of terms / types: dots made part of long
  1976 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1977 
  1978 * simpset (and claset) reference variable replaced by functions
  1979 simpset / simpset_ref;
  1980 
  1981 * no longer supports theory aliases (via merge) and non-trivial
  1982 implicit merge of thms' signatures;
  1983 
  1984 * most internal names of constants changed due to qualified names;
  1985 
  1986 * changed Pure/Sequence interface (see Pure/seq.ML);
  1987 
  1988 
  1989 *** General Changes ***
  1990 
  1991 * hierachically structured name spaces (for consts, types, axms, thms
  1992 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1993 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1994 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1995 long_names for fully qualified output names; NOTE: ML programs
  1996 (special tactics, packages etc.) referring to internal names may have
  1997 to be adapted to cope with fully qualified names; in case of severe
  1998 backward campatibility problems try setting 'global_names' at compile
  1999 time to have enrything declared within a flat name space; one may also
  2000 fine tune name declarations in theories via the 'global' and 'local'
  2001 section;
  2002 
  2003 * reimplemented the implicit simpset and claset using the new anytype
  2004 data filed in signatures; references simpset:simpset ref etc. are
  2005 replaced by functions simpset:unit->simpset and
  2006 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2007 to patch your ML files accordingly;
  2008 
  2009 * HTML output now includes theory graph data for display with Java
  2010 applet or isatool browser; data generated automatically via isatool
  2011 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2012 
  2013 * defs may now be conditional; improved rewrite_goals_tac to handle
  2014 conditional equations;
  2015 
  2016 * defs now admits additional type arguments, using TYPE('a) syntax;
  2017 
  2018 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2019 creates a new theory node; implicit merge of thms' signatures is
  2020 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2021 transfer:theory->thm->thm in (rare) cases;
  2022 
  2023 * improved handling of draft signatures / theories; draft thms (and
  2024 ctyps, cterms) are automatically promoted to real ones;
  2025 
  2026 * slightly changed interfaces for oracles: admit many per theory, named
  2027 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2028 
  2029 * print_goals: optional output of const types (set show_consts and
  2030 show_types);
  2031 
  2032 * improved output of warnings (###) and errors (***);
  2033 
  2034 * subgoal_tac displays a warning if the new subgoal has type variables;
  2035 
  2036 * removed old README and Makefiles;
  2037 
  2038 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2039 
  2040 * removed obsolete init_pps and init_database;
  2041 
  2042 * deleted the obsolete tactical STATE, which was declared by
  2043     fun STATE tacfun st = tacfun st st;
  2044 
  2045 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2046 (which abbreviates $HOME);
  2047 
  2048 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2049 use isatool fixseq to adapt your ML programs (this works for fully
  2050 qualified references to the Sequence structure only!);
  2051 
  2052 * use_thy no longer requires writable current directory; it always
  2053 reloads .ML *and* .thy file, if either one is out of date;
  2054 
  2055 
  2056 *** Classical Reasoner ***
  2057 
  2058 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2059 tactics that use classical reasoning to simplify a subgoal without
  2060 splitting it into several subgoals;
  2061 
  2062 * Safe_tac: like safe_tac but uses the default claset;
  2063 
  2064 
  2065 *** Simplifier ***
  2066 
  2067 * added simplification meta rules:
  2068     (asm_)(full_)simplify: simpset -> thm -> thm;
  2069 
  2070 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2071 logics (again);
  2072 
  2073 * added prems argument to simplification procedures;
  2074 
  2075 * HOL, FOL, ZF: added infix function `addsplits':
  2076   instead of `<simpset> setloop (split_tac <thms>)'
  2077   you can simply write `<simpset> addsplits <thms>'
  2078 
  2079 
  2080 *** Syntax ***
  2081 
  2082 * TYPE('a) syntax for type reflection terms;
  2083 
  2084 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2085 
  2086 * pretty printer: changed order of mixfix annotation preference (again!);
  2087 
  2088 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2089 
  2090 
  2091 *** HOL ***
  2092 
  2093 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2094   with `addloop' of the simplifier to faciliate case splitting in premises.
  2095 
  2096 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2097 
  2098 * HOL/Auth: new protocol proofs including some for the Internet
  2099   protocol TLS;
  2100 
  2101 * HOL/Map: new theory of `maps' a la VDM;
  2102 
  2103 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2104 cancelling out common nat summands from =, <, <= (in)equalities, or
  2105 differences; simplification procedures nat_cancel_factor for
  2106 cancelling common factor from =, <, <= (in)equalities over natural
  2107 sums; nat_cancel contains both kinds of procedures, it is installed by
  2108 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2109 
  2110 * HOL/simplifier: terms of the form
  2111   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2112   are rewritten to
  2113   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2114   and those of the form
  2115   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2116   are rewritten to
  2117   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2118 
  2119 * HOL/datatype
  2120   Each datatype `t' now comes with a theorem `split_t_case' 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 
  2128   and a theorem `split_t_case_asm' of the form
  2129 
  2130   P(t_case f1 ... fn x) =
  2131     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2132         ...
  2133        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2134      )
  2135   which can be added to a simpset via `addsplits'. The existing theorems
  2136   expand_list_case and expand_option_case have been renamed to
  2137   split_list_case and split_option_case.
  2138 
  2139 * HOL/Arithmetic:
  2140   - `pred n' is automatically converted to `n-1'.
  2141     Users are strongly encouraged not to use `pred' any longer,
  2142     because it will disappear altogether at some point.
  2143   - Users are strongly encouraged to write "0 < n" rather than
  2144     "n ~= 0". Theorems and proof tools have been modified towards this
  2145     `standard'.
  2146 
  2147 * HOL/Lists:
  2148   the function "set_of_list" has been renamed "set" (and its theorems too);
  2149   the function "nth" now takes its arguments in the reverse order and
  2150   has acquired the infix notation "!" as in "xs!n".
  2151 
  2152 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2153 
  2154 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2155   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2156 
  2157 * HOL/record: extensible records with schematic structural subtyping
  2158 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2159 still lacks various theorems and concrete record syntax;
  2160 
  2161 
  2162 *** HOLCF ***
  2163 
  2164 * removed "axioms" and "generated by" sections;
  2165 
  2166 * replaced "ops" section by extended "consts" section, which is capable of
  2167   handling the continuous function space "->" directly;
  2168 
  2169 * domain package:
  2170   . proves theorems immediately and stores them in the theory,
  2171   . creates hierachical name space,
  2172   . now uses normal mixfix annotations (instead of cinfix...),
  2173   . minor changes to some names and values (for consistency),
  2174   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2175   . separator between mutual domain defs: changed "," to "and",
  2176   . improved handling of sort constraints;  now they have to
  2177     appear on the left-hand side of the equations only;
  2178 
  2179 * fixed LAM <x,y,zs>.b syntax;
  2180 
  2181 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2182 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2183 
  2184 
  2185 *** FOL and ZF ***
  2186 
  2187 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2188   with `addloop' of the simplifier to faciliate case splitting in premises.
  2189 
  2190 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2191 in HOL, they strip ALL and --> from proved theorems;
  2192 
  2193 
  2194 
  2195 New in Isabelle94-8 (May 1997)
  2196 ------------------------------
  2197 
  2198 *** General Changes ***
  2199 
  2200 * new utilities to build / run / maintain Isabelle etc. (in parts
  2201 still somewhat experimental); old Makefiles etc. still functional;
  2202 
  2203 * new 'Isabelle System Manual';
  2204 
  2205 * INSTALL text, together with ./configure and ./build scripts;
  2206 
  2207 * reimplemented type inference for greater efficiency, better error
  2208 messages and clean internal interface;
  2209 
  2210 * prlim command for dealing with lots of subgoals (an easier way of
  2211 setting goals_limit);
  2212 
  2213 
  2214 *** Syntax ***
  2215 
  2216 * supports alternative (named) syntax tables (parser and pretty
  2217 printer); internal interface is provided by add_modesyntax(_i);
  2218 
  2219 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2220 be used in conjunction with the Isabelle symbol font; uses the
  2221 "symbols" syntax table;
  2222 
  2223 * added token_translation interface (may translate name tokens in
  2224 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2225 the current print_mode); IMPORTANT: user print translation functions
  2226 are responsible for marking newly introduced bounds
  2227 (Syntax.mark_boundT);
  2228 
  2229 * token translations for modes "xterm" and "xterm_color" that display
  2230 names in bold, underline etc. or colors (which requires a color
  2231 version of xterm);
  2232 
  2233 * infixes may now be declared with names independent of their syntax;
  2234 
  2235 * added typed_print_translation (like print_translation, but may
  2236 access type of constant);
  2237 
  2238 
  2239 *** Classical Reasoner ***
  2240 
  2241 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2242 some limitations.  Blast_tac...
  2243   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2244   + ignores elimination rules that don't have the correct format
  2245         (the conclusion MUST be a formula variable)
  2246   + ignores types, which can make HOL proofs fail
  2247   + rules must not require higher-order unification, e.g. apply_type in ZF
  2248     [message "Function Var's argument not a bound variable" relates to this]
  2249   + its proof strategy is more general but can actually be slower
  2250 
  2251 * substitution with equality assumptions no longer permutes other
  2252 assumptions;
  2253 
  2254 * minor changes in semantics of addafter (now called addaltern); renamed
  2255 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2256 (and access functions for it);
  2257 
  2258 * improved combination of classical reasoner and simplifier:
  2259   + functions for handling clasimpsets
  2260   + improvement of addss: now the simplifier is called _after_ the
  2261     safe steps.
  2262   + safe variant of addss called addSss: uses safe simplifications
  2263     _during_ the safe steps. It is more complete as it allows multiple
  2264     instantiations of unknowns (e.g. with slow_tac).
  2265 
  2266 *** Simplifier ***
  2267 
  2268 * added interface for simplification procedures (functions that
  2269 produce *proven* rewrite rules on the fly, depending on current
  2270 redex);
  2271 
  2272 * ordering on terms as parameter (used for ordered rewriting);
  2273 
  2274 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2275 
  2276 * the solver is now split into a safe and an unsafe part.
  2277 This should be invisible for the normal user, except that the
  2278 functions setsolver and addsolver have been renamed to setSolver and
  2279 addSolver; added safe_asm_full_simp_tac;
  2280 
  2281 
  2282 *** HOL ***
  2283 
  2284 * a generic induction tactic `induct_tac' which works for all datatypes and
  2285 also for type `nat';
  2286 
  2287 * a generic case distinction tactic `exhaust_tac' which works for all
  2288 datatypes and also for type `nat';
  2289 
  2290 * each datatype comes with a function `size';
  2291 
  2292 * patterns in case expressions allow tuple patterns as arguments to
  2293 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2294 
  2295 * primrec now also works with type nat;
  2296 
  2297 * recdef: a new declaration form, allows general recursive functions to be
  2298 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2299 
  2300 * the constant for negation has been renamed from "not" to "Not" to
  2301 harmonize with FOL, ZF, LK, etc.;
  2302 
  2303 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2304 infinite lists;
  2305 
  2306 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2307 
  2308 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2309 problems in commutative rings, using axiomatic type classes for + and *;
  2310 
  2311 * more examples in HOL/MiniML and HOL/Auth;
  2312 
  2313 * more default rewrite rules for quantifiers, union/intersection;
  2314 
  2315 * a new constant `arbitrary == @x.False';
  2316 
  2317 * HOLCF/IOA replaces old HOL/IOA;
  2318 
  2319 * HOLCF changes: derived all rules and arities
  2320   + axiomatic type classes instead of classes
  2321   + typedef instead of faking type definitions
  2322   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2323   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2324   + eliminated the types void, one, tr
  2325   + use unit lift and bool lift (with translations) instead of one and tr
  2326   + eliminated blift from Lift3.thy (use Def instead of blift)
  2327   all eliminated rules are derived as theorems --> no visible changes ;
  2328 
  2329 
  2330 *** ZF ***
  2331 
  2332 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2333 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2334 as ZF_cs addSIs [equalityI];
  2335 
  2336 
  2337 
  2338 New in Isabelle94-7 (November 96)
  2339 ---------------------------------
  2340 
  2341 * allowing negative levels (as offsets) in prlev and choplev;
  2342 
  2343 * super-linear speedup for large simplifications;
  2344 
  2345 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2346 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2347 FAIL); can suppress it using the command Delsimps (ex_simps @
  2348 all_simps); De Morgan laws are also now included, by default;
  2349 
  2350 * improved printing of ==>  :  ~:
  2351 
  2352 * new object-logic "Sequents" adds linear logic, while replacing LK
  2353 and Modal (thanks to Sara Kalvala);
  2354 
  2355 * HOL/Auth: correctness proofs for authentication protocols;
  2356 
  2357 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2358 examples on HOL/Auth);
  2359 
  2360 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2361 the rewriter and classical reasoner simultaneously;
  2362 
  2363 * function uresult no longer returns theorems in "standard" format;
  2364 regain previous version by: val uresult = standard o uresult;
  2365 
  2366 
  2367 
  2368 New in Isabelle94-6
  2369 -------------------
  2370 
  2371 * oracles -- these establish an interface between Isabelle and trusted
  2372 external reasoners, which may deliver results as theorems;
  2373 
  2374 * proof objects (in particular record all uses of oracles);
  2375 
  2376 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2377 
  2378 * "constdefs" section in theory files;
  2379 
  2380 * "primrec" section (HOL) no longer requires names;
  2381 
  2382 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2383 
  2384 
  2385 
  2386 New in Isabelle94-5
  2387 -------------------
  2388 
  2389 * reduced space requirements;
  2390 
  2391 * automatic HTML generation from theories;
  2392 
  2393 * theory files no longer require "..." (quotes) around most types;
  2394 
  2395 * new examples, including two proofs of the Church-Rosser theorem;
  2396 
  2397 * non-curried (1994) version of HOL is no longer distributed;
  2398 
  2399 
  2400 
  2401 New in Isabelle94-4
  2402 -------------------
  2403 
  2404 * greatly reduced space requirements;
  2405 
  2406 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2407 
  2408 * searchable theorem database (see the section "Retrieving theorems" on
  2409 page 8 of the Reference Manual);
  2410 
  2411 * new examples, including Grabczewski's monumental case study of the
  2412 Axiom of Choice;
  2413 
  2414 * The previous version of HOL renamed to Old_HOL;
  2415 
  2416 * The new version of HOL (previously called CHOL) uses a curried syntax
  2417 for functions.  Application looks like f a b instead of f(a,b);
  2418 
  2419 * Mutually recursive inductive definitions finally work in HOL;
  2420 
  2421 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2422 translates to the operator "split";
  2423 
  2424 
  2425 
  2426 New in Isabelle94-3
  2427 -------------------
  2428 
  2429 * new infix operator, addss, allowing the classical reasoner to
  2430 perform simplification at each step of its search.  Example:
  2431         fast_tac (cs addss ss)
  2432 
  2433 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2434 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2435 look like (a,b) instead of <a,b>;
  2436 
  2437 * PLEASE NOTE: CHOL will eventually replace HOL!
  2438 
  2439 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2440 It translates to the operator "split".  A new theory of integers is available;
  2441 
  2442 * In ZF, integer numerals now denote two's-complement binary integers.
  2443 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2444 
  2445 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2446 of the Axiom of Choice;
  2447 
  2448 
  2449 
  2450 New in Isabelle94-2
  2451 -------------------
  2452 
  2453 * Significantly faster resolution;
  2454 
  2455 * the different sections in a .thy file can now be mixed and repeated
  2456 freely;
  2457 
  2458 * Database of theorems for FOL, HOL and ZF.  New
  2459 commands including qed, qed_goal and bind_thm store theorems in the database.
  2460 
  2461 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2462 a given theory (thms_of), or find out what theory a theorem was proved in
  2463 (theory_of_thm);
  2464 
  2465 * Bugs fixed in the inductive definition and datatype packages;
  2466 
  2467 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2468 and HOL_dup_cs obsolete;
  2469 
  2470 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2471 have been removed;
  2472 
  2473 * Simpler definition of function space in ZF;
  2474 
  2475 * new results about cardinal and ordinal arithmetic in ZF;
  2476 
  2477 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2478 types;
  2479 
  2480 
  2481 $Id$