NEWS
author nipkow
Wed Feb 04 03:44:05 2004 +0100 (2004-02-04)
changeset 14375 a545da363b23
parent 14361 ad2f5da643b4
child 14380 04b603a6f17d
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * 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 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    21 
    22 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    23   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    24   a normal (but invisible) letter. For multiple letter subscripts repeat 
    25   \<^isub> like this: x\<^isub>1\<^isub>2. 
    26 
    27 * Pure: There are now sub-/superscripts that can span more than one
    28   character. Text between \<^bsub> and \<^esub> is set in subscript in
    29   PG and LaTeX, text between \<^bsup> and \<^esup> in superscript. The
    30   new control characters are not identifier parts.
    31 
    32 * Pure: Control-symbols of the form \<^raw...> will literally print the
    33   content of ... to the latex file instead of \isacntrl... . The ... 
    34   accepts all printable characters excluding the end bracket >.
    35 
    36 * Pure: Symbols may only start with one backslash: \<...>. \\<...> is no 
    37   longer accepted by the scanner.
    38 
    39 * Pure: Using new Isar command "finalconsts" (or the ML functions
    40   Theory.add_finals or Theory.add_finals_i) it is now possible to
    41   declare constants "final", which prevents their being given a definition
    42   later.  It is useful for constants whose behaviour is fixed axiomatically
    43   rather than definitionally, such as the meta-logic connectives.
    44 
    45 *** Isar ***
    46 
    47 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    48   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    49     locales are no longer forced to write Isar proof scripts.
    50     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    51     emulations.
    52   - INCOMPATIBILITY: names of variables to be instantiated may no
    53     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    54     This is consistent with the instantiation attribute "where".
    55 
    56 * Attributes "where" and "of":
    57   - Now take type variables of instantiated theorem into account when reading
    58     the instantiation string.  This fixes a bug that caused instantiated
    59     theorems to have too special types in some circumstances.
    60   - "where" permits explicit instantiations of type variables.
    61 
    62 * Calculation commands "moreover" and "also":
    63   Do not reset facts ("this") any more.
    64 
    65 * Locales:
    66   - Goal statements involving the context element "includes" no longer
    67     generate theorems with internal delta predicates (those ending on
    68     "_axioms") in the premise.
    69     Resolve particular premise with <locale>.intro to obtain old form.
    70   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    71     specification and "includes" elements in goal statement.
    72   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    73     [intro?] and [elim?] (respectively) by default.
    74 
    75 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    76   (Isar) contexts.
    77 
    78 *** HOL ***
    79 
    80 * Records:
    81   - Record types are now by default printed with their type abbreviation
    82     instead of the list of all field types. This can be configured via
    83     the reference "print_record_type_abbr".
    84   - Simproc "record_upd_simproc" for simplification of multiple updates added 
    85     (not enabled by default).
    86   - Tactic "record_split_simp_tac" to split and simplify records added.
    87  
    88 * 'specification' command added, allowing for definition by
    89   specification.  There is also an 'ax_specification' command that
    90   introduces the new constants axiomatically.
    91 
    92 
    93 * arith(_tac) is now able to generate counterexamples for reals as well.
    94 
    95 * SET-Protocol: formalization and verification of the SET protocol suite;
    96 
    97 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
    98  defintions, thanks to Sava Krsti\'{c} and John Matthews.
    99 
   100 New in Isabelle2003 (May 2003)
   101 --------------------------------
   102 
   103 *** General ***
   104 
   105 * Provers/simplifier:
   106 
   107   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   108     Assumptions are now subject to complete mutual simplification,
   109     not just from left to right. The simplifier now preserves
   110     the order of assumptions.
   111 
   112     Potential INCOMPATIBILITY:
   113 
   114     -- simp sometimes diverges where the old version did
   115        not, e.g. invoking simp on the goal
   116 
   117         [| P (f x); y = x; f x = f y |] ==> Q
   118 
   119        now gives rise to the infinite reduction sequence
   120 
   121         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   122 
   123        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   124        kind of problem.
   125 
   126     -- Tactics combining classical reasoner and simplification (such as auto)
   127        are also affected by this change, because many of them rely on
   128        simp. They may sometimes diverge as well or yield a different numbers
   129        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   130        in case of problems. Sometimes subsequent calls to the classical
   131        reasoner will fail because a preceeding call to the simplifier too
   132        eagerly simplified the goal, e.g. deleted redundant premises.
   133 
   134   - The simplifier trace now shows the names of the applied rewrite rules
   135 
   136   - You can limit the number of recursive invocations of the simplifier
   137     during conditional rewriting (where the simplifie tries to solve the
   138     conditions before applying the rewrite rule):
   139     ML "simp_depth_limit := n"
   140     where n is an integer. Thus you can force termination where previously
   141     the simplifier would diverge.
   142 
   143   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   144 
   145   - No longer aborts on failed congruence proof.  Instead, the
   146     congruence is ignored.
   147 
   148 * Pure: New generic framework for extracting programs from constructive
   149   proofs. See HOL/Extraction.thy for an example instantiation, as well
   150   as HOL/Extraction for some case studies.
   151 
   152 * Pure: The main goal of the proof state is no longer shown by default, only
   153 the subgoals. This behaviour is controlled by a new flag.
   154    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   155 (ML: Proof.show_main_goal).
   156 
   157 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   158 rules whose conclusion matches subgoal 1:
   159       PG menu: Isabelle/Isar -> Show me -> matching rules
   160 The rules are ordered by how closely they match the subgoal.
   161 In particular, rules that solve a subgoal outright are displayed first
   162 (or rather last, the way they are printed).
   163 (ML: ProofGeneral.print_intros())
   164 
   165 * Pure: New flag trace_unify_fail causes unification to print
   166 diagnostic information (PG: in trace buffer) when it fails. This is
   167 useful for figuring out why single step proofs like rule, erule or
   168 assumption failed.
   169 
   170 * Pure: Locale specifications now produce predicate definitions
   171 according to the body of text (covering assumptions modulo local
   172 definitions); predicate "loc_axioms" covers newly introduced text,
   173 while "loc" is cumulative wrt. all included locale expressions; the
   174 latter view is presented only on export into the global theory
   175 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   176 on the old view without predicates;
   177 
   178 * Pure: predefined locales "var" and "struct" are useful for sharing
   179 parameters (as in CASL, for example); just specify something like
   180 ``var x + var y + struct M'' as import;
   181 
   182 * Pure: improved thms_containing: proper indexing of facts instead of
   183 raw theorems; check validity of results wrt. current name space;
   184 include local facts of proof configuration (also covers active
   185 locales), cover fixed variables in index; may use "_" in term
   186 specification; an optional limit for the number of printed facts may
   187 be given (the default is 40);
   188 
   189 * Pure: disallow duplicate fact bindings within new-style theory files
   190 (batch-mode only);
   191 
   192 * Provers: improved induct method: assumptions introduced by case
   193 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   194 the goal statement); "foo" still refers to all facts collectively;
   195 
   196 * Provers: the function blast.overloaded has been removed: all constants
   197 are regarded as potentially overloaded, which improves robustness in exchange
   198 for slight decrease in efficiency;
   199 
   200 * Provers/linorder: New generic prover for transitivity reasoning over
   201 linear orders.  Note: this prover is not efficient!
   202 
   203 * Isar: preview of problems to finish 'show' now produce an error
   204 rather than just a warning (in interactive mode);
   205 
   206 
   207 *** HOL ***
   208 
   209 * arith(_tac)
   210 
   211  - Produces a counter example if it cannot prove a goal.
   212    Note that the counter example may be spurious if the goal is not a formula
   213    of quantifier-free linear arithmetic.
   214    In ProofGeneral the counter example appears in the trace buffer.
   215 
   216  - Knows about div k and mod k where k is a numeral of type nat or int.
   217 
   218  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   219    linear arithmetic fails. This takes account of quantifiers and divisibility.
   220    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   221 
   222 * simp's arithmetic capabilities have been enhanced a bit: it now
   223 takes ~= in premises into account (by performing a case split);
   224 
   225 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   226 are distributed over a sum of terms;
   227 
   228 * New tactic "trans_tac" and method "trans" instantiate
   229 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   230 "<=", "<" and "="). 
   231 
   232 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   233 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   234 
   235 * 'typedef' command has new option "open" to suppress the set
   236 definition;
   237 
   238 * functions Min and Max on finite sets have been introduced (theory
   239 Finite_Set);
   240 
   241 * attribute [symmetric] now works for relations as well; it turns
   242 (x,y) : R^-1 into (y,x) : R, and vice versa;
   243 
   244 * induct over a !!-quantified statement (say !!x1..xn):
   245   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   246 
   247 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   248 %x. None. Warning: empty_def now refers to the previously hidden definition
   249 of the empty set.
   250 
   251 * Algebra: formalization of classical algebra.  Intended as base for
   252 any algebraic development in Isabelle.  Currently covers group theory
   253 (up to Sylow's theorem) and ring theory (Universal Property of
   254 Univariate Polynomials).  Contributions welcome;
   255 
   256 * GroupTheory: deleted, since its material has been moved to Algebra;
   257 
   258 * Complex: new directory of the complex numbers with numeric constants, 
   259 nonstandard complex numbers, and some complex analysis, standard and 
   260 nonstandard (Jacques Fleuriot);
   261 
   262 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   263 
   264 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   265 Fleuriot);
   266 
   267 * Real/HahnBanach: updated and adapted to locales;
   268 
   269 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   270 Gray and Kramer);
   271 
   272 * UNITY: added the Meier-Sanders theory of progress sets;
   273 
   274 * MicroJava: bytecode verifier and lightweight bytecode verifier
   275 as abstract algorithms, instantiated to the JVM;
   276 
   277 * Bali: Java source language formalization. Type system, operational
   278 semantics, axiomatic semantics. Supported language features:
   279 classes, interfaces, objects,virtual methods, static methods,
   280 static/instance fields, arrays, access modifiers, definite
   281 assignment, exceptions.
   282 
   283 
   284 *** ZF ***
   285 
   286 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   287 universe, etc.);
   288 
   289 * Main ZF: virtually all theories converted to new-style format;
   290 
   291 
   292 *** ML ***
   293 
   294 * Pure: Tactic.prove provides sane interface for internal proofs;
   295 omits the infamous "standard" operation, so this is more appropriate
   296 than prove_goalw_cterm in many situations (e.g. in simprocs);
   297 
   298 * Pure: improved error reporting of simprocs;
   299 
   300 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   301 up simprocs;
   302 
   303 
   304 *** Document preparation ***
   305 
   306 * uses \par instead of \\ for line breaks in theory text. This may
   307 shift some page breaks in large documents. To get the old behaviour
   308 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   309 
   310 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   311 other packages
   312 
   313 * \<euro> now needs package babel/greek instead of marvosym (which
   314 broke \Rightarrow)
   315 
   316 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   317 textcomp package)
   318 
   319 
   320 New in Isabelle2002 (March 2002)
   321 --------------------------------
   322 
   323 *** Document preparation ***
   324 
   325 * greatly simplified document preparation setup, including more
   326 graceful interpretation of isatool usedir -i/-d/-D options, and more
   327 instructive isatool mkdir; users should basically be able to get
   328 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   329 users may run a separate document processing stage manually like this:
   330 "isatool usedir -D output HOL Test && isatool document Test/output";
   331 
   332 * theory dependency graph may now be incorporated into documents;
   333 isatool usedir -g true will produce session_graph.eps/.pdf for use
   334 with \includegraphics of LaTeX;
   335 
   336 * proper spacing of consecutive markup elements, especially text
   337 blocks after section headings;
   338 
   339 * support bold style (for single symbols only), input syntax is like
   340 this: "\<^bold>\<alpha>" or "\<^bold>A";
   341 
   342 * \<bullet> is now output as bold \cdot by default, which looks much
   343 better in printed text;
   344 
   345 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   346 note that these symbols are currently unavailable in Proof General /
   347 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   348 
   349 * isatool latex no longer depends on changed TEXINPUTS, instead
   350 isatool document copies the Isabelle style files to the target
   351 location;
   352 
   353 
   354 *** Isar ***
   355 
   356 * Pure/Provers: improved proof by cases and induction;
   357   - 'case' command admits impromptu naming of parameters (such as
   358     "case (Suc n)");
   359   - 'induct' method divinates rule instantiation from the inductive
   360     claim; no longer requires excessive ?P bindings for proper
   361     instantiation of cases;
   362   - 'induct' method properly enumerates all possibilities of set/type
   363     rules; as a consequence facts may be also passed through *type*
   364     rules without further ado;
   365   - 'induct' method now derives symbolic cases from the *rulified*
   366     rule (before it used to rulify cases stemming from the internal
   367     atomized version); this means that the context of a non-atomic
   368     statement becomes is included in the hypothesis, avoiding the
   369     slightly cumbersome show "PROP ?case" form;
   370   - 'induct' may now use elim-style induction rules without chaining
   371     facts, using ``missing'' premises from the goal state; this allows
   372     rules stemming from inductive sets to be applied in unstructured
   373     scripts, while still benefitting from proper handling of non-atomic
   374     statements; NB: major inductive premises need to be put first, all
   375     the rest of the goal is passed through the induction;
   376   - 'induct' proper support for mutual induction involving non-atomic
   377     rule statements (uses the new concept of simultaneous goals, see
   378     below);
   379   - append all possible rule selections, but only use the first
   380     success (no backtracking);
   381   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   382   - undeclared rule case names default to numbers 1, 2, 3, ...;
   383   - added 'print_induct_rules' (covered by help item in recent Proof
   384     General versions);
   385   - moved induct/cases attributes to Pure, methods to Provers;
   386   - generic method setup instantiated for FOL and HOL;
   387 
   388 * Pure: support multiple simultaneous goal statements, for example
   389 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   390 meta-level mechanism, this acts as if several individual goals had
   391 been stated separately; in particular common proof methods need to be
   392 repeated in order to cover all claims; note that a single elimination
   393 step is *not* sufficient to establish the two conjunctions, so this
   394 fails:
   395 
   396   assume "A & B" then have A and B ..   (*".." fails*)
   397 
   398 better use "obtain" in situations as above; alternative refer to
   399 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   400 
   401 * Pure: proper integration with ``locales''; unlike the original
   402 version by Florian Kammüller, Isar locales package high-level proof
   403 contexts rather than raw logical ones (e.g. we admit to include
   404 attributes everywhere); operations on locales include merge and
   405 rename; support for implicit arguments (``structures''); simultaneous
   406 type-inference over imports and text; see also HOL/ex/Locales.thy for
   407 some examples;
   408 
   409 * Pure: the following commands have been ``localized'', supporting a
   410 target locale specification "(in name)": 'lemma', 'theorem',
   411 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   412 stored both within the locale and at the theory level (exported and
   413 qualified by the locale name);
   414 
   415 * Pure: theory goals may now be specified in ``long'' form, with
   416 ad-hoc contexts consisting of arbitrary locale elements. for example
   417 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   418 definitions may be given, too); the result is a meta-level rule with
   419 the context elements being discharged in the obvious way;
   420 
   421 * Pure: new proof command 'using' allows to augment currently used
   422 facts after a goal statement ('using' is syntactically analogous to
   423 'apply', but acts on the goal's facts only); this allows chained facts
   424 to be separated into parts given before and after a claim, as in
   425 ``from a and b have C using d and e <proof>'';
   426 
   427 * Pure: renamed "antecedent" case to "rule_context";
   428 
   429 * Pure: new 'judgment' command records explicit information about the
   430 object-logic embedding (used by several tools internally); no longer
   431 use hard-wired "Trueprop";
   432 
   433 * Pure: added 'corollary' command;
   434 
   435 * Pure: fixed 'token_translation' command;
   436 
   437 * Pure: removed obsolete 'exported' attribute;
   438 
   439 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   440 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   441 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   442 
   443 * Pure: method 'atomize' presents local goal premises as object-level
   444 statements (atomic meta-level propositions); setup controlled via
   445 rewrite rules declarations of 'atomize' attribute; example
   446 application: 'induct' method with proper rule statements in improper
   447 proof *scripts*;
   448 
   449 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   450 now consider the syntactic context of assumptions, giving a better
   451 chance to get type-inference of the arguments right (this is
   452 especially important for locales);
   453 
   454 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   455 mode;
   456 
   457 * Pure/obtain: the formal conclusion "thesis", being marked as
   458 ``internal'', may no longer be reference directly in the text;
   459 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   460 situations;
   461 
   462 * Pure: generic 'sym' attribute which declares a rule both as pure
   463 'elim?' and for the 'symmetric' operation;
   464 
   465 * Pure: marginal comments ``--'' may now occur just anywhere in the
   466 text; the fixed correlation with particular command syntax has been
   467 discontinued;
   468 
   469 * Pure: new method 'rules' is particularly well-suited for proof
   470 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   471 but often produces more compact proof terms with less detours;
   472 
   473 * Pure/Provers/classical: simplified integration with pure rule
   474 attributes and methods; the classical "intro?/elim?/dest?"
   475 declarations coincide with the pure ones; the "rule" method no longer
   476 includes classically swapped intros; "intro" and "elim" methods no
   477 longer pick rules from the context; also got rid of ML declarations
   478 AddXIs/AddXEs/AddXDs; all of this has some potential for
   479 INCOMPATIBILITY;
   480 
   481 * Provers/classical: attribute 'swapped' produces classical inversions
   482 of introduction rules;
   483 
   484 * Provers/simplifier: 'simplified' attribute may refer to explicit
   485 rules instead of full simplifier context; 'iff' attribute handles
   486 conditional rules;
   487 
   488 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   489 
   490 * HOL: 'recdef' now fails on unfinished automated proofs, use
   491 "(permissive)" option to recover old behavior;
   492 
   493 * HOL: 'inductive' no longer features separate (collective) attributes
   494 for 'intros' (was found too confusing);
   495 
   496 * HOL: properly declared induction rules less_induct and
   497 wf_induct_rule;
   498 
   499 
   500 *** HOL ***
   501 
   502 * HOL: moved over to sane numeral syntax; the new policy is as
   503 follows:
   504 
   505   - 0 and 1 are polymorphic constants, which are defined on any
   506   numeric type (nat, int, real etc.);
   507 
   508   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   509   binary representation internally;
   510 
   511   - type nat has special constructor Suc, and generally prefers Suc 0
   512   over 1::nat and Suc (Suc 0) over 2::nat;
   513 
   514 This change may cause significant problems of INCOMPATIBILITY; here
   515 are some hints on converting existing sources:
   516 
   517   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   518   entities, so expressions involving "-" (unary or binary minus) need
   519   to be spaced properly;
   520 
   521   - existing occurrences of "1" may need to be constraint "1::nat" or
   522   even replaced by Suc 0; similar for old "2";
   523 
   524   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   525 
   526   - remove all special provisions on numerals in proofs;
   527 
   528 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   529 representation (depends on bin_arith_simps in the default context);
   530 
   531 * HOL: symbolic syntax for x^2 (numeral 2);
   532 
   533 * HOL: the class of all HOL types is now called "type" rather than
   534 "term"; INCOMPATIBILITY, need to adapt references to this type class
   535 in axclass/classes, instance/arities, and (usually rare) occurrences
   536 in typings (of consts etc.); internally the class is called
   537 "HOL.type", ML programs should refer to HOLogic.typeS;
   538 
   539 * HOL/record package improvements:
   540   - new derived operations "fields" to build a partial record section,
   541     "extend" to promote a fixed record to a record scheme, and
   542     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   543     declared as simp by default;
   544   - shared operations ("more", "fields", etc.) now need to be always
   545     qualified) --- potential INCOMPATIBILITY;
   546   - removed "make_scheme" operations (use "make" with "extend") --
   547     INCOMPATIBILITY;
   548   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   549   - provides cases/induct rules for use with corresponding Isar
   550     methods (for concrete records, record schemes, concrete more
   551     parts, and schematic more parts -- in that order);
   552   - internal definitions directly based on a light-weight abstract
   553     theory of product types over typedef rather than datatype;
   554 
   555 * HOL: generic code generator for generating executable ML code from
   556 specifications; specific support for HOL constructs such as inductive
   557 datatypes and sets, as well as recursive functions; can be invoked
   558 via 'generate_code' theory section;
   559 
   560 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   561 
   562 * HOL: consolidated and renamed several theories.  In particular:
   563 	Ord.thy has been absorbed into HOL.thy
   564 	String.thy has been absorbed into List.thy
   565  
   566 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   567 (beware of argument permutation!);
   568 
   569 * HOL: linorder_less_split superseded by linorder_cases;
   570 
   571 * HOL/List: "nodups" renamed to "distinct";
   572 
   573 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   574 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   575   - Ex_def has changed, now need to use some_eq_ex
   576 
   577 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   578 in this (rare) case use:
   579 
   580   delSWrapper "split_all_tac"
   581   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   582 
   583 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   584 MAY FAIL;
   585 
   586 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   587 Isabelle's type classes, ^ on functions and relations has too general
   588 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   589 necessary to attach explicit type constraints;
   590 
   591 * HOL/Relation: the prefix name of the infix "O" has been changed from
   592 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   593 renamed accordingly (eg "compI" -> "rel_compI").
   594 
   595 * HOL: syntax translations now work properly with numerals and records
   596 expressions;
   597 
   598 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   599 of "lam" -- INCOMPATIBILITY;
   600 
   601 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   602 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   603 renamed "Product_Type.unit";
   604 
   605 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   606 
   607 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   608 the "cases" method);
   609 
   610 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   611 Florian Kammüller);
   612 
   613 * HOL/IMP: updated and converted to new-style theory format; several
   614 parts turned into readable document, with proper Isar proof texts and
   615 some explanations (by Gerwin Klein);
   616 
   617 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   618 
   619 * HOL-Hyperreal is now a logic image;
   620 
   621 
   622 *** HOLCF ***
   623 
   624 * Isar: consts/constdefs supports mixfix syntax for continuous
   625 operations;
   626 
   627 * Isar: domain package adapted to new-style theory format, e.g. see
   628 HOLCF/ex/Dnat.thy;
   629 
   630 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   631 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   632 lift.induct_tac, always use UU instead of Undef;
   633 
   634 * HOLCF/IMP: updated and converted to new-style theory;
   635 
   636 
   637 *** ZF ***
   638 
   639 * Isar: proper integration of logic-specific tools and packages,
   640 including theory commands '(co)inductive', '(co)datatype',
   641 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   642 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   643 
   644 * theory Main no longer includes AC; for the Axiom of Choice, base
   645 your theory on Main_ZFC;
   646 
   647 * the integer library now covers quotients and remainders, with many
   648 laws relating division to addition, multiplication, etc.;
   649 
   650 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   651 typeless version of the formalism;
   652 
   653 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   654 format;
   655 
   656 * ZF/Induct: new directory for examples of inductive definitions,
   657 including theory Multiset for multiset orderings; converted to
   658 new-style theory format;
   659 
   660 * ZF: many new theorems about lists, ordinals, etc.;
   661 
   662 
   663 *** General ***
   664 
   665 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   666 variable proof controls level of detail: 0 = no proofs (only oracle
   667 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   668 also ref manual for further ML interfaces;
   669 
   670 * Pure/axclass: removed obsolete ML interface
   671 goal_subclass/goal_arity;
   672 
   673 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   674 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   675 separate tokens, so expressions involving minus need to be spaced
   676 properly;
   677 
   678 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   679 rather than "infixl" or "infixr";
   680 
   681 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   682 sort constraint specifications in type inference; e.g. "x::_::foo"
   683 ensures that the type of "x" is of sort "foo" (but not necessarily a
   684 type variable);
   685 
   686 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   687 control output of nested => (types); the default behavior is
   688 "type_brackets";
   689 
   690 * Pure/syntax: builtin parse translation for "_constify" turns valued
   691 tokens into AST constants;
   692 
   693 * Pure/syntax: prefer later declarations of translations and print
   694 translation functions; potential INCOMPATIBILITY: need to reverse
   695 multiple declarations for same syntax element constant;
   696 
   697 * Pure/show_hyps reset by default (in accordance to existing Isar
   698 practice);
   699 
   700 * Provers/classical: renamed addaltern to addafter, addSaltern to
   701 addSafter;
   702 
   703 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   704 as well;
   705 
   706 * system: tested support for MacOS X; should be able to get Isabelle +
   707 Proof General to work in a plain Terminal after installing Poly/ML
   708 (e.g. from the Isabelle distribution area) and GNU bash alone
   709 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   710 support requires further installations, e.g. from
   711 http://fink.sourceforge.net/);
   712 
   713 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   714 
   715 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   716 of 40 MB), cf. ML_OPTIONS;
   717 
   718 * system: Proof General keywords specification is now part of the
   719 Isabelle distribution (see etc/isar-keywords.el);
   720 
   721 * system: support for persistent Proof General sessions (refrain from
   722 outdating all loaded theories on startup); user may create writable
   723 logic images like this: ``isabelle -q HOL Test'';
   724 
   725 * system: smart selection of Isabelle process versus Isabelle
   726 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   727 run both "isabelle" and "Isabelle" even if file names are badly
   728 damaged (executable inspects the case of the first letter of its own
   729 name); added separate "isabelle-process" and "isabelle-interface";
   730 
   731 * system: refrain from any attempt at filtering input streams; no
   732 longer support ``8bit'' encoding of old isabelle font, instead proper
   733 iso-latin characters may now be used; the related isatools
   734 "symbolinput" and "nonascii" have disappeared as well;
   735 
   736 * system: removed old "xterm" interface (the print modes "xterm" and
   737 "xterm_color" are still available for direct use in a suitable
   738 terminal);
   739 
   740 
   741 
   742 New in Isabelle99-2 (February 2001)
   743 -----------------------------------
   744 
   745 *** Overview of INCOMPATIBILITIES ***
   746 
   747 * HOL: please note that theories in the Library and elsewhere often use the
   748 new-style (Isar) format; to refer to their theorems in an ML script you must
   749 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   750 
   751 * HOL: inductive package no longer splits induction rule aggressively,
   752 but only as far as specified by the introductions given; the old
   753 format may be recovered via ML function complete_split_rule or attribute
   754 'split_rule (complete)';
   755 
   756 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   757 gfp_Tarski to gfp_unfold;
   758 
   759 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   760 
   761 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   762 relation); infix "^^" has been renamed "``"; infix "``" has been
   763 renamed "`"; "univalent" has been renamed "single_valued";
   764 
   765 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   766 operation;
   767 
   768 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   769 
   770 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   771 
   772 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   773 consequence, it is no longer monotonic wrt. the local goal context
   774 (which is now passed through the inductive cases);
   775 
   776 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   777 \<gg> to \<ggreater>;
   778 
   779 
   780 *** Document preparation ***
   781 
   782 * \isabellestyle{NAME} selects version of Isabelle output (currently
   783 available: are "it" for near math-mode best-style output, "sl" for
   784 slanted text style, and "tt" for plain type-writer; if no
   785 \isabellestyle command is given, output is according to slanted
   786 type-writer);
   787 
   788 * support sub/super scripts (for single symbols only), input syntax is
   789 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   790 
   791 * some more standard symbols; see Appendix A of the system manual for
   792 the complete list of symbols defined in isabellesym.sty;
   793 
   794 * improved isabelle style files; more abstract symbol implementation
   795 (should now use \isamath{...} and \isatext{...} in custom symbol
   796 definitions);
   797 
   798 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   799 state; Note that presentation of goal states does not conform to
   800 actual human-readable proof documents.  Please do not include goal
   801 states into document output unless you really know what you are doing!
   802 
   803 * proper indentation of antiquoted output with proportional LaTeX
   804 fonts;
   805 
   806 * no_document ML operator temporarily disables LaTeX document
   807 generation;
   808 
   809 * isatool unsymbolize tunes sources for plain ASCII communication;
   810 
   811 
   812 *** Isar ***
   813 
   814 * Pure: Isar now suffers initial goal statements to contain unbound
   815 schematic variables (this does not conform to actual readable proof
   816 documents, due to unpredictable outcome and non-compositional proof
   817 checking); users who know what they are doing may use schematic goals
   818 for Prolog-style synthesis of proven results;
   819 
   820 * Pure: assumption method (an implicit finishing) now handles actual
   821 rules as well;
   822 
   823 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   824 initial goal, declare "that" only as Pure intro (only for single
   825 steps); the "that" rule assumption may now be involved in implicit
   826 finishing, thus ".." becomes a feasible for trivial obtains;
   827 
   828 * Pure: default proof step now includes 'intro_classes'; thus trivial
   829 instance proofs may be performed by "..";
   830 
   831 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   832 statements as well;
   833 
   834 * Pure: more robust selection of calculational rules;
   835 
   836 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   837 rule (as well as the assumption rule);
   838 
   839 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   840 lemmas, using the graph browser tool;
   841 
   842 * Pure: predict failure of "show" in interactive mode;
   843 
   844 * Pure: 'thms_containing' now takes actual terms as arguments;
   845 
   846 * HOL: improved method 'induct' --- now handles non-atomic goals
   847 (potential INCOMPATIBILITY); tuned error handling;
   848 
   849 * HOL: cases and induct rules now provide explicit hints about the
   850 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   851 any remaining facts are inserted into the goal verbatim;
   852 
   853 * HOL: local contexts (aka cases) may now contain term bindings as
   854 well; the 'cases' and 'induct' methods new provide a ?case binding for
   855 the result to be shown in each case;
   856 
   857 * HOL: added 'recdef_tc' command;
   858 
   859 * isatool convert assists in eliminating legacy ML scripts;
   860 
   861 
   862 *** HOL ***
   863 
   864 * HOL/Library: a collection of generic theories to be used together
   865 with main HOL; the theory loader path already includes this directory
   866 by default; the following existing theories have been moved here:
   867 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   868 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   869 
   870 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   871 modelling and verification task performed in Isabelle/HOL +
   872 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   873 
   874 * HOL/Algebra: special summation operator SUM no longer exists, it has
   875 been replaced by setsum; infix 'assoc' now has priority 50 (like
   876 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   877 'domain', this makes the theory consistent with mathematical
   878 literature;
   879 
   880 * HOL basics: added overloaded operations "inverse" and "divide"
   881 (infix "/"), syntax for generic "abs" operation, generic summation
   882 operator \<Sum>;
   883 
   884 * HOL/typedef: simplified package, provide more useful rules (see also
   885 HOL/subset.thy);
   886 
   887 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   888 now expressed as a proper nested rule (old-style tactic scripts may
   889 require atomize_strip_tac to cope with non-atomic premises);
   890 
   891 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   892 to "split_conv" (old name still available for compatibility);
   893 
   894 * HOL: improved concrete syntax for strings (e.g. allows translation
   895 rules with string literals);
   896 
   897 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   898  and Fleuriot's mechanization of analysis, including the transcendental
   899  functions for the reals;
   900 
   901 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   902 
   903 
   904 *** CTT ***
   905 
   906 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   907 "lam" is displayed as TWO lambda-symbols
   908 
   909 * CTT: theory Main now available, containing everything (that is, Bool
   910 and Arith);
   911 
   912 
   913 *** General ***
   914 
   915 * Pure: the Simplifier has been implemented properly as a derived rule
   916 outside of the actual kernel (at last!); the overall performance
   917 penalty in practical applications is about 50%, while reliability of
   918 the Isabelle inference kernel has been greatly improved;
   919 
   920 * print modes "brackets" and "no_brackets" control output of nested =>
   921 (types) and ==> (props); the default behaviour is "brackets";
   922 
   923 * Provers: fast_tac (and friends) now handle actual object-logic rules
   924 as assumptions as well;
   925 
   926 * system: support Poly/ML 4.0;
   927 
   928 * system: isatool install handles KDE version 1 or 2;
   929 
   930 
   931 
   932 New in Isabelle99-1 (October 2000)
   933 ----------------------------------
   934 
   935 *** Overview of INCOMPATIBILITIES ***
   936 
   937 * HOL: simplification of natural numbers is much changed; to partly
   938 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   939 issue the following ML commands:
   940 
   941   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   942   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   943 
   944 * HOL: simplification no longer dives into case-expressions; this is
   945 controlled by "t.weak_case_cong" for each datatype t;
   946 
   947 * HOL: nat_less_induct renamed to less_induct;
   948 
   949 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   950 fixsome to patch .thy and .ML sources automatically;
   951 
   952   select_equality  -> some_equality
   953   select_eq_Ex     -> some_eq_ex
   954   selectI2EX       -> someI2_ex
   955   selectI2         -> someI2
   956   selectI          -> someI
   957   select1_equality -> some1_equality
   958   Eps_sym_eq       -> some_sym_eq_trivial
   959   Eps_eq           -> some_eq_trivial
   960 
   961 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   962 
   963 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   964 instead);
   965 
   966 * HOL: the recursion equations generated by 'recdef' are now called
   967 f.simps instead of f.rules;
   968 
   969 * HOL: qed_spec_mp now also handles bounded ALL as well;
   970 
   971 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   972 sometimes be needed;
   973 
   974 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   975 
   976 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   977 
   978 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   979 product is now "<*>" instead of "Times"; the lexicographic product is
   980 now "<*lex*>" instead of "**";
   981 
   982 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   983 of main HOL, but was unused); better use HOL's datatype package;
   984 
   985 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   986 the old syntax may be recovered as follows:
   987 
   988   syntax (symbols)
   989     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   990       (infixl "\\<oplus>" 100)
   991 
   992 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   993 
   994 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   995 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   996 internally;
   997 
   998 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   999 changed from A/r to A//r;
  1000 
  1001 * ZF: new treatment of arithmetic (nat & int) may break some old
  1002 proofs;
  1003 
  1004 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1005 rulify -> rule_format, elimify -> elim_format, ...);
  1006 
  1007 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1008 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1009 should have to change intro!! to intro? only); replaced "delrule" by
  1010 "rule del";
  1011 
  1012 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1013 
  1014 * Provers: strengthened force_tac by using new first_best_tac;
  1015 
  1016 * LaTeX document preparation: several changes of isabelle.sty (see
  1017 lib/texinputs);
  1018 
  1019 
  1020 *** Document preparation ***
  1021 
  1022 * formal comments (text blocks etc.) in new-style theories may now
  1023 contain antiquotations of thm/prop/term/typ/text to be presented
  1024 according to latex print mode; concrete syntax is like this:
  1025 @{term[show_types] "f(x) = a + x"};
  1026 
  1027 * isatool mkdir provides easy setup of Isabelle session directories,
  1028 including proper document sources;
  1029 
  1030 * generated LaTeX sources are now deleted after successful run
  1031 (isatool document -c); may retain a copy somewhere else via -D option
  1032 of isatool usedir;
  1033 
  1034 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1035 style files, achieving self-contained LaTeX sources and simplifying
  1036 LaTeX debugging;
  1037 
  1038 * old-style theories now produce (crude) LaTeX output as well;
  1039 
  1040 * browser info session directories are now self-contained (may be put
  1041 on WWW server seperately); improved graphs of nested sessions; removed
  1042 graph for 'all sessions';
  1043 
  1044 * several improvements in isabelle style files; \isabellestyle{it}
  1045 produces fake math mode output; \isamarkupheader is now \section by
  1046 default; see lib/texinputs/isabelle.sty etc.;
  1047 
  1048 
  1049 *** Isar ***
  1050 
  1051 * Isar/Pure: local results and corresponding term bindings are now
  1052 subject to Hindley-Milner polymorphism (similar to ML); this
  1053 accommodates incremental type-inference very nicely;
  1054 
  1055 * Isar/Pure: new derived language element 'obtain' supports
  1056 generalized existence reasoning;
  1057 
  1058 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1059 support accumulation of results, without applying any rules yet;
  1060 useful to collect intermediate results without explicit name
  1061 references, and for use with transitivity rules with more than 2
  1062 premises;
  1063 
  1064 * Isar/Pure: scalable support for case-analysis type proofs: new
  1065 'case' language element refers to local contexts symbolically, as
  1066 produced by certain proof methods; internally, case names are attached
  1067 to theorems as "tags";
  1068 
  1069 * Isar/Pure: theory command 'hide' removes declarations from
  1070 class/type/const name spaces;
  1071 
  1072 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1073 indicate potential overloading;
  1074 
  1075 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1076 
  1077 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1078 "{a,b,c}" instead of {a,b,c};
  1079 
  1080 * Isar/Pure now provides its own version of intro/elim/dest
  1081 attributes; useful for building new logics, but beware of confusion
  1082 with the version in Provers/classical;
  1083 
  1084 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1085 case name 'antecedent';
  1086 
  1087 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1088 to the current context is now done automatically);
  1089 
  1090 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1091 for definining proof methods in ML;
  1092 
  1093 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1094 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1095 most cases, one should have to change intro!! to intro? only);
  1096 replaced "delrule" by "rule del";
  1097 
  1098 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1099 'symmetric' attribute (the latter supercedes [RS sym]);
  1100 
  1101 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1102 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1103 well (including splits);
  1104 
  1105 * Isar/Provers: Simplifier and Classical methods now support all kind
  1106 of modifiers used in the past, including 'cong', 'iff', etc.
  1107 
  1108 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1109 of Simplifier and Classical reasoner);
  1110 
  1111 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1112 now support named cases; major packages (inductive, datatype, primrec,
  1113 recdef) support case names and properly name parameters;
  1114 
  1115 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1116 monotonicity conditions are extracted to be proven at end of
  1117 calculations;
  1118 
  1119 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1120 method anyway;
  1121 
  1122 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1123 split_if split_if_asm; datatype package provides theorems foo.splits =
  1124 foo.split foo.split_asm for each datatype;
  1125 
  1126 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1127 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1128 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1129 use "(cases (simplified))" method in proper proof texts);
  1130 
  1131 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1132 
  1133 * Isar: names of theorems etc. may be natural numbers as well;
  1134 
  1135 * Isar: 'pr' command: optional arguments for goals_limit and
  1136 ProofContext.prems_limit; no longer prints theory contexts, but only
  1137 proof states;
  1138 
  1139 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1140 additional print modes to be specified; e.g. "pr(latex)" will print
  1141 proof state according to the Isabelle LaTeX style;
  1142 
  1143 * Isar: improved support for emulating tactic scripts, including proof
  1144 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1145 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1146 (for HOL datatypes);
  1147 
  1148 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1149 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1150 'proof method scripts' have to be in depth-first order;
  1151 
  1152 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1153 
  1154 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1155 should instead use individual commands for printing items
  1156 (print_commands, print_methods etc.);
  1157 
  1158 * Isar: added 'nothing' --- the empty list of theorems;
  1159 
  1160 
  1161 *** HOL ***
  1162 
  1163 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1164 corresponding virtual machine and a specification of its bytecode
  1165 verifier and a lightweight bytecode verifier, including proofs of
  1166 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1167 Cornelia Pusch (see also the homepage of project Bali at
  1168 http://isabelle.in.tum.de/Bali/);
  1169 
  1170 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1171 Clemens Ballarin;
  1172 
  1173 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1174 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1175 Rasmussen;
  1176 
  1177 * HOL/Lattice: fundamental concepts of lattice theory and order
  1178 structures, including duals, properties of bounds versus algebraic
  1179 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1180 Theorem for complete lattices etc.; may also serve as a demonstration
  1181 for abstract algebraic reasoning using axiomatic type classes, and
  1182 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1183 
  1184 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1185 von Oheimb;
  1186 
  1187 * HOL/IMPP: extension of IMP with local variables and mutually
  1188 recursive procedures, by David von Oheimb;
  1189 
  1190 * HOL/Lambda: converted into new-style theory and document;
  1191 
  1192 * HOL/ex/Multiquote: example of multiple nested quotations and
  1193 anti-quotations -- basically a generalized version of de-Bruijn
  1194 representation; very useful in avoiding lifting of operations;
  1195 
  1196 * HOL/record: added general record equality rule to simpset; fixed
  1197 select-update simplification procedure to handle extended records as
  1198 well; admit "r" as field name;
  1199 
  1200 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1201 other numeric types and also as the identity of groups, rings, etc.;
  1202 
  1203 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1204 Types nat and int belong to this axclass;
  1205 
  1206 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1207    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1208    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1209   two terms #m*u and #n*u are replaced by #(m+n)*u
  1210     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1211   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1212     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1213 
  1214 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1215 powerful prover for predicate logic but knows nothing of clasets; see
  1216 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1217 
  1218 * HOL: new version of "case_tac" subsumes both boolean case split and
  1219 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1220 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1221 
  1222 * HOL: simplification no longer dives into case-expressions: only the
  1223 selector expression is simplified, but not the remaining arms; to
  1224 enable full simplification of case-expressions for datatype t, you may
  1225 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1226 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1227 
  1228 * HOL/recdef: the recursion equations generated by 'recdef' for
  1229 function 'f' are now called f.simps instead of f.rules; if all
  1230 termination conditions are proved automatically, these simplification
  1231 rules are added to the simpset, as in primrec; rules may be named
  1232 individually as well, resulting in a separate list of theorems for
  1233 each equation;
  1234 
  1235 * HOL/While is a new theory that provides a while-combinator. It
  1236 permits the definition of tail-recursive functions without the
  1237 provision of a termination measure. The latter is necessary once the
  1238 invariant proof rule for while is applied.
  1239 
  1240 * HOL: new (overloaded) notation for the set of elements below/above
  1241 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1242 
  1243 * HOL: theorems impI, allI, ballI bound as "strip";
  1244 
  1245 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1246 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1247 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1248 
  1249 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1250 
  1251 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1252 main HOL, but was unused);
  1253 
  1254 * HOL: fewer consts declared as global (e.g. have to refer to
  1255 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1256 
  1257 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1258 in case of overlap with user translations (e.g. judgements over
  1259 tuples); (note that the underlying logical represenation is still
  1260 bogus);
  1261 
  1262 
  1263 *** ZF ***
  1264 
  1265 * ZF: simplification automatically cancels common terms in arithmetic
  1266 expressions over nat and int;
  1267 
  1268 * ZF: new treatment of nat to minimize type-checking: all operators
  1269 coerce their operands to a natural number using the function natify,
  1270 making the algebraic laws unconditional;
  1271 
  1272 * ZF: as above, for int: operators coerce their operands to an integer
  1273 using the function intify;
  1274 
  1275 * ZF: the integer library now contains many of the usual laws for the
  1276 orderings, including $<=, and monotonicity laws for $+ and $*;
  1277 
  1278 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1279 simplification;
  1280 
  1281 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1282 to the simplifier and classical reasoner simultaneously;
  1283 
  1284 
  1285 *** General ***
  1286 
  1287 * Provers: blast_tac now handles actual object-logic rules as
  1288 assumptions; note that auto_tac uses blast_tac internally as well;
  1289 
  1290 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1291 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1292 
  1293 * Provers: delrules now handles destruct rules as well (no longer need
  1294 explicit make_elim);
  1295 
  1296 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1297   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1298 use instead the strong form,
  1299   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1300 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1301 from destruct-rules;
  1302 
  1303 * Provers: Simplifier.easy_setup provides a fast path to basic
  1304 Simplifier setup for new object-logics;
  1305 
  1306 * Pure: AST translation rules no longer require constant head on LHS;
  1307 
  1308 * Pure: improved name spaces: ambiguous output is qualified; support
  1309 for hiding of names;
  1310 
  1311 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1312 XSYMBOL_HOME; no longer need to do manual configuration in most
  1313 situations;
  1314 
  1315 * system: compression of ML heaps images may now be controlled via -c
  1316 option of isabelle and isatool usedir (currently only observed by
  1317 Poly/ML);
  1318 
  1319 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1320 useful for remote X11);
  1321 
  1322 * system: provide TAGS file for Isabelle sources;
  1323 
  1324 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1325 order;
  1326 
  1327 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1328 timing flag supersedes proof_timing and Toplevel.trace;
  1329 
  1330 * ML: new combinators |>> and |>>> for incremental transformations
  1331 with secondary results (e.g. certain theory extensions):
  1332 
  1333 * ML: PureThy.add_defs gets additional argument to indicate potential
  1334 overloading (usually false);
  1335 
  1336 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1337 results;
  1338 
  1339 
  1340 
  1341 New in Isabelle99 (October 1999)
  1342 --------------------------------
  1343 
  1344 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1345 
  1346 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1347 are no longer simplified.  (This allows the simplifier to unfold recursive
  1348 functional programs.)  To restore the old behaviour, declare
  1349 
  1350     Delcongs [if_weak_cong];
  1351 
  1352 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1353 complement;
  1354 
  1355 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1356 
  1357 * HOL/datatype: mutual_induct_tac no longer exists --
  1358   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1359 
  1360 * HOL/typedef: fixed type inference for representing set; type
  1361 arguments now have to occur explicitly on the rhs as type constraints;
  1362 
  1363 * ZF: The con_defs part of an inductive definition may no longer refer
  1364 to constants declared in the same theory;
  1365 
  1366 * HOL, ZF: the function mk_cases, generated by the inductive
  1367 definition package, has lost an argument.  To simplify its result, it
  1368 uses the default simpset instead of a supplied list of theorems.
  1369 
  1370 * HOL/List: the constructors of type list are now Nil and Cons;
  1371 
  1372 * Simplifier: the type of the infix ML functions
  1373         setSSolver addSSolver setSolver addSolver
  1374 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1375 for packaging solvers. A solver is created via
  1376         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1377 where the string argument is only a comment.
  1378 
  1379 
  1380 *** Proof tools ***
  1381 
  1382 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1383 decision procedure for linear arithmetic. Currently it is used for
  1384 types `nat', `int', and `real' in HOL (see below); it can, should and
  1385 will be instantiated for other types and logics as well.
  1386 
  1387 * The simplifier now accepts rewrite rules with flexible heads, eg
  1388      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1389   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1390   matching.
  1391 
  1392 
  1393 *** General ***
  1394 
  1395 * New Isabelle/Isar subsystem provides an alternative to traditional
  1396 tactical theorem proving; together with the ProofGeneral/isar user
  1397 interface it offers an interactive environment for developing human
  1398 readable proof documents (Isar == Intelligible semi-automated
  1399 reasoning); for further information see isatool doc isar-ref,
  1400 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1401 
  1402 * improved and simplified presentation of theories: better HTML markup
  1403 (including colors), graph views in several sizes; isatool usedir now
  1404 provides a proper interface for user theories (via -P option); actual
  1405 document preparation based on (PDF)LaTeX is available as well (for
  1406 new-style theories only); see isatool doc system for more information;
  1407 
  1408 * native support for Proof General, both for classic Isabelle and
  1409 Isabelle/Isar;
  1410 
  1411 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1412 using the graph browser tool;
  1413 
  1414 * Isabelle manuals now also available as PDF;
  1415 
  1416 * theory loader rewritten from scratch (may not be fully
  1417 bug-compatible); old loadpath variable has been replaced by show_path,
  1418 add_path, del_path, reset_path functions; new operations such as
  1419 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1420 isatool doc ref);
  1421 
  1422 * improved isatool install: option -k creates KDE application icon,
  1423 option -p DIR installs standalone binaries;
  1424 
  1425 * added ML_PLATFORM setting (useful for cross-platform installations);
  1426 more robust handling of platform specific ML images for SML/NJ;
  1427 
  1428 * the settings environment is now statically scoped, i.e. it is never
  1429 created again in sub-processes invoked from isabelle, isatool, or
  1430 Isabelle;
  1431 
  1432 * path element specification '~~' refers to '$ISABELLE_HOME';
  1433 
  1434 * in locales, the "assumes" and "defines" parts may be omitted if
  1435 empty;
  1436 
  1437 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1438 long arrows);
  1439 
  1440 * new print_mode "HTML";
  1441 
  1442 * new flag show_tags controls display of tags of theorems (which are
  1443 basically just comments that may be attached by some tools);
  1444 
  1445 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1446 mode and goal output format:
  1447 
  1448 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1449 244c244
  1450 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1451 ---
  1452 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1453 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1454 181c181
  1455 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1456 ---
  1457 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1458 
  1459 * function bind_thms stores lists of theorems (cf. bind_thm);
  1460 
  1461 * new shorthand tactics ftac, eatac, datac, fatac;
  1462 
  1463 * qed (and friends) now accept "" as result name; in that case the
  1464 theorem is not stored, but proper checks and presentation of the
  1465 result still apply;
  1466 
  1467 * theorem database now also indexes constants "Trueprop", "all",
  1468 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1469 
  1470 
  1471 *** HOL ***
  1472 
  1473 ** HOL arithmetic **
  1474 
  1475 * There are now decision procedures for linear arithmetic over nat and
  1476 int:
  1477 
  1478 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1479 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1480 are treated as atomic; subformulae not involving type `nat' or `int'
  1481 are ignored; quantified subformulae are ignored unless they are
  1482 positive universal or negative existential. The tactic has to be
  1483 invoked by hand and can be a little bit slow. In particular, the
  1484 running time is exponential in the number of occurrences of `min' and
  1485 `max', and `-' on `nat'.
  1486 
  1487 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1488 (negated) (in)equalities among the premises and the conclusion into
  1489 account (i.e. no compound formulae) and does not know about `min' and
  1490 `max', and `-' on `nat'. It is fast and is used automatically by the
  1491 simplifier.
  1492 
  1493 NB: At the moment, these decision procedures do not cope with mixed
  1494 nat/int formulae where the two parts interact, such as `m < n ==>
  1495 int(m) < int(n)'.
  1496 
  1497 * HOL/Numeral provides a generic theory of numerals (encoded
  1498 efficiently as bit strings); setup for types nat/int/real is in place;
  1499 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1500 int, existing theories and proof scripts may require a few additional
  1501 type constraints;
  1502 
  1503 * integer division and remainder can now be performed on constant
  1504 arguments;
  1505 
  1506 * many properties of integer multiplication, division and remainder
  1507 are now available;
  1508 
  1509 * An interface to the Stanford Validity Checker (SVC) is available through the
  1510 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1511 are proved automatically.  SVC must be installed separately, and its results
  1512 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1513 invocation of the underlying oracle).  For SVC see
  1514   http://verify.stanford.edu/SVC
  1515 
  1516 * IsaMakefile: the HOL-Real target now builds an actual image;
  1517 
  1518 
  1519 ** HOL misc **
  1520 
  1521 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1522 (in Isabelle/Isar) -- by Gertrud Bauer;
  1523 
  1524 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1525 analysis for assembly languages with subtypes;
  1526 
  1527 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1528 -- avoids syntactic ambiguities and treats state, transition, and
  1529 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1530 changed syntax and (many) tactics;
  1531 
  1532 * HOL/inductive: Now also handles more general introduction rules such
  1533   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1534   theorems are now maintained within the theory (maintained via the
  1535   "mono" attribute);
  1536 
  1537 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1538   (using function types) such as
  1539 
  1540   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1541 
  1542 * HOL/record: record_simproc (part of the default simpset) takes care
  1543 of selectors applied to updated records; record_split_tac is no longer
  1544 part of the default claset; update_defs may now be removed from the
  1545 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1546 
  1547   claset_ref () := claset() addSWrapper record_split_wrapper;
  1548   Delsimprocs [record_simproc]
  1549 
  1550 * HOL/typedef: fixed type inference for representing set; type
  1551 arguments now have to occur explicitly on the rhs as type constraints;
  1552 
  1553 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1554 names rather than an ML expression;
  1555 
  1556 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1557 supplied later.  Program schemes can be defined, such as
  1558     "While B C s = (if B s then While B C (C s) else s)"
  1559 where the well-founded relation can be chosen after B and C have been given.
  1560 
  1561 * HOL/List: the constructors of type list are now Nil and Cons;
  1562 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1563 course, ML tools referring to List.list.op # etc. have to be adapted;
  1564 
  1565 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1566 disabled by default; run isabelle with option -m HOL to get back to
  1567 the original Gordon/HOL-style output;
  1568 
  1569 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1570 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1571 
  1572 * HOL basic syntax simplified (more orthogonal): all variants of
  1573 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1574 Eps operator is provided as well: "SOME x. P[x]";
  1575 
  1576 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1577 
  1578 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1579 thus available for user theories;
  1580 
  1581 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1582 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1583 time;
  1584 
  1585 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1586 several times and then mp;
  1587 
  1588 
  1589 *** LK ***
  1590 
  1591 * the notation <<...>> is now available as a notation for sequences of
  1592 formulas;
  1593 
  1594 * the simplifier is now installed
  1595 
  1596 * the axiom system has been generalized (thanks to Soren Heilmann)
  1597 
  1598 * the classical reasoner now has a default rule database
  1599 
  1600 
  1601 *** ZF ***
  1602 
  1603 * new primrec section allows primitive recursive functions to be given
  1604 directly (as in HOL) over datatypes and the natural numbers;
  1605 
  1606 * new tactics induct_tac and exhaust_tac for induction (or case
  1607 analysis) over datatypes and the natural numbers;
  1608 
  1609 * the datatype declaration of type T now defines the recursor T_rec;
  1610 
  1611 * simplification automatically does freeness reasoning for datatype
  1612 constructors;
  1613 
  1614 * automatic type-inference, with AddTCs command to insert new
  1615 type-checking rules;
  1616 
  1617 * datatype introduction rules are now added as Safe Introduction rules
  1618 to the claset;
  1619 
  1620 * the syntax "if P then x else y" is now available in addition to
  1621 if(P,x,y);
  1622 
  1623 
  1624 *** Internal programming interfaces ***
  1625 
  1626 * tuned simplifier trace output; new flag debug_simp;
  1627 
  1628 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1629 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1630 
  1631 * AxClass.axclass_tac lost the theory argument;
  1632 
  1633 * tuned current_goals_markers semantics: begin / end goal avoids
  1634 printing empty lines;
  1635 
  1636 * removed prs and prs_fn hook, which was broken because it did not
  1637 include \n in its semantics, forcing writeln to add one
  1638 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1639 string -> unit if you really want to output text without newline;
  1640 
  1641 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1642 plain output, interface builders may have to enable 'isabelle_font'
  1643 mode to get Isabelle font glyphs as before;
  1644 
  1645 * refined token_translation interface; INCOMPATIBILITY: output length
  1646 now of type real instead of int;
  1647 
  1648 * theory loader actions may be traced via new ThyInfo.add_hook
  1649 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1650 your own database of information attached to *whole* theories -- as
  1651 opposed to intra-theory data slots offered via TheoryDataFun;
  1652 
  1653 * proper handling of dangling sort hypotheses (at last!);
  1654 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1655 extra sort hypotheses that can be witnessed from the type signature;
  1656 the force_strip_shyps flag is gone, any remaining shyps are simply
  1657 left in the theorem (with a warning issued by strip_shyps_warning);
  1658 
  1659 
  1660 
  1661 New in Isabelle98-1 (October 1998)
  1662 ----------------------------------
  1663 
  1664 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1665 
  1666 * several changes of automated proof tools;
  1667 
  1668 * HOL: major changes to the inductive and datatype packages, including
  1669 some minor incompatibilities of theory syntax;
  1670 
  1671 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1672 called `inj_on';
  1673 
  1674 * HOL: removed duplicate thms in Arith:
  1675   less_imp_add_less  should be replaced by  trans_less_add1
  1676   le_imp_add_le      should be replaced by  trans_le_add1
  1677 
  1678 * HOL: unary minus is now overloaded (new type constraints may be
  1679 required);
  1680 
  1681 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1682 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1683 now taken as an integer constant.
  1684 
  1685 * Pure: ML function 'theory_of' renamed to 'theory';
  1686 
  1687 
  1688 *** Proof tools ***
  1689 
  1690 * Simplifier:
  1691   1. Asm_full_simp_tac is now more aggressive.
  1692      1. It will sometimes reorient premises if that increases their power to
  1693         simplify.
  1694      2. It does no longer proceed strictly from left to right but may also
  1695         rotate premises to achieve further simplification.
  1696      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1697      old Asm_full_simp_tac in that it does not rotate premises.
  1698   2. The simplifier now knows a little bit about nat-arithmetic.
  1699 
  1700 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1701 allows for selected deletion of wrappers, by introduction of names for
  1702 wrapper functionals.  This implies that addbefore, addSbefore,
  1703 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1704 and that adding two tactics with the same name overwrites the first
  1705 one (emitting a warning).
  1706   type wrapper = (int -> tactic) -> (int -> tactic)
  1707   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1708   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1709   delWrapper, delSWrapper: claset *  string            -> claset
  1710   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1711 
  1712 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1713 semantics; addbefore now affects only the unsafe part of step_tac
  1714 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1715 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1716 by Force_tac;
  1717 
  1718 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1719 compWrapper; added safe wrapper (and access functions for it);
  1720 
  1721 * HOL/split_all_tac is now much faster and fails if there is nothing
  1722 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1723 and the names of the automatically generated variables have changed.
  1724 split_all_tac has moved within claset() from unsafe wrappers to safe
  1725 wrappers, which means that !!-bound variables are split much more
  1726 aggressively, and safe_tac and clarify_tac now split such variables.
  1727 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1728 Note: the same holds for record_split_tac, which does the job of
  1729 split_all_tac for record fields.
  1730 
  1731 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1732 permanently to the default simpset using Addsplits just like
  1733 Addsimps. They can be removed via Delsplits just like
  1734 Delsimps. Lower-case versions are also available.
  1735 
  1736 * HOL/Simplifier: The rule split_if is now part of the default
  1737 simpset. This means that the simplifier will eliminate all occurrences
  1738 of if-then-else in the conclusion of a goal. To prevent this, you can
  1739 either remove split_if completely from the default simpset by
  1740 `Delsplits [split_if]' or remove it in a specific call of the
  1741 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1742 other case splitting rules to/from the default simpset: every datatype
  1743 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1744 t is the name of the datatype).
  1745 
  1746 * Classical reasoner / Simplifier combination: new force_tac (and
  1747 derivatives Force_tac, force) combines rewriting and classical
  1748 reasoning (and whatever other tools) similarly to auto_tac, but is
  1749 aimed to solve the given subgoal completely.
  1750 
  1751 
  1752 *** General ***
  1753 
  1754 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1755 and `goalw': the theory is no longer needed as an explicit argument -
  1756 the current theory context is used; assumptions are no longer returned
  1757 at the ML-level unless one of them starts with ==> or !!; it is
  1758 recommended to convert to these new commands using isatool fixgoal
  1759 (backup your sources first!);
  1760 
  1761 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1762 the current theory context, and 'theory' to lookup stored theories;
  1763 
  1764 * new theory section 'locale' for declaring constants, assumptions and
  1765 definitions that have local scope;
  1766 
  1767 * new theory section 'nonterminals' for purely syntactic types;
  1768 
  1769 * new theory section 'setup' for generic ML setup functions
  1770 (e.g. package initialization);
  1771 
  1772 * the distribution now includes Isabelle icons: see
  1773 lib/logo/isabelle-{small,tiny}.xpm;
  1774 
  1775 * isatool install - install binaries with absolute references to
  1776 ISABELLE_HOME/bin;
  1777 
  1778 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1779 
  1780 * print mode 'emacs' reserved for Isamode;
  1781 
  1782 * support multiple print (ast) translations per constant name;
  1783 
  1784 * theorems involving oracles are now printed with a suffixed [!];
  1785 
  1786 
  1787 *** HOL ***
  1788 
  1789 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1790 
  1791 * HOL/inductive package reorganized and improved: now supports mutual
  1792 definitions such as
  1793 
  1794   inductive EVEN ODD
  1795     intrs
  1796       null "0 : EVEN"
  1797       oddI "n : EVEN ==> Suc n : ODD"
  1798       evenI "n : ODD ==> Suc n : EVEN"
  1799 
  1800 new theorem list "elims" contains an elimination rule for each of the
  1801 recursive sets; inductive definitions now handle disjunctive premises
  1802 correctly (also ZF);
  1803 
  1804 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1805 "mutual_induct" no longer exists - the induction rule is always
  1806 contained in "induct";
  1807 
  1808 
  1809 * HOL/datatype package re-implemented and greatly improved: now
  1810 supports mutually recursive datatypes such as
  1811 
  1812   datatype
  1813     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1814             | SUM ('a aexp) ('a aexp)
  1815             | DIFF ('a aexp) ('a aexp)
  1816             | NUM 'a
  1817   and
  1818     'a bexp = LESS ('a aexp) ('a aexp)
  1819             | AND ('a bexp) ('a bexp)
  1820             | OR ('a bexp) ('a bexp)
  1821 
  1822 as well as indirectly recursive datatypes such as
  1823 
  1824   datatype
  1825     ('a, 'b) term = Var 'a
  1826                   | App 'b ((('a, 'b) term) list)
  1827 
  1828 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1829 induction on mutually / indirectly recursive datatypes.
  1830 
  1831 Primrec equations are now stored in theory and can be accessed via
  1832 <function_name>.simps.
  1833 
  1834 INCOMPATIBILITIES:
  1835 
  1836   - Theories using datatypes must now have theory Datatype as an
  1837     ancestor.
  1838   - The specific <typename>.induct_tac no longer exists - use the
  1839     generic induct_tac instead.
  1840   - natE has been renamed to nat.exhaust - use exhaust_tac
  1841     instead of res_inst_tac ... natE. Note that the variable
  1842     names in nat.exhaust differ from the names in natE, this
  1843     may cause some "fragile" proofs to fail.
  1844   - The theorems split_<typename>_case and split_<typename>_case_asm
  1845     have been renamed to <typename>.split and <typename>.split_asm.
  1846   - Since default sorts of type variables are now handled correctly,
  1847     some datatype definitions may have to be annotated with explicit
  1848     sort constraints.
  1849   - Primrec definitions no longer require function name and type
  1850     of recursive argument.
  1851 
  1852 Consider using isatool fixdatatype to adapt your theories and proof
  1853 scripts to the new package (backup your sources first!).
  1854 
  1855 
  1856 * HOL/record package: considerably improved implementation; now
  1857 includes concrete syntax for record types, terms, updates; theorems
  1858 for surjective pairing and splitting !!-bound record variables; proof
  1859 support is as follows:
  1860 
  1861   1) standard conversions (selectors or updates applied to record
  1862 constructor terms) are part of the standard simpset;
  1863 
  1864   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1865 made part of standard simpset and claset via addIffs;
  1866 
  1867   3) a tactic for record field splitting (record_split_tac) is part of
  1868 the standard claset (addSWrapper);
  1869 
  1870 To get a better idea about these rules you may retrieve them via
  1871 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1872 the name of your record type.
  1873 
  1874 The split tactic 3) conceptually simplifies by the following rule:
  1875 
  1876   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1877 
  1878 Thus any record variable that is bound by meta-all will automatically
  1879 blow up into some record constructor term, consequently the
  1880 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1881 solve record problems automatically.
  1882 
  1883 
  1884 * reorganized the main HOL image: HOL/Integ and String loaded by
  1885 default; theory Main includes everything;
  1886 
  1887 * automatic simplification of integer sums and comparisons, using cancellation;
  1888 
  1889 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1890 
  1891 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1892 
  1893 * many new identities for unions, intersections, set difference, etc.;
  1894 
  1895 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1896 called split_if, split_split, split_sum_case and split_nat_case (to go
  1897 with add/delsplits);
  1898 
  1899 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1900 (?x::unit) = (); this is made part of the default simpset, which COULD
  1901 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1902 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1903 unit_abs_eta_conv is added in order to counter the effect of
  1904 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1905 %u.f();
  1906 
  1907 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1908 makes more sense);
  1909 
  1910 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1911   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1912   disjointness reasoning but breaking a few old proofs.
  1913 
  1914 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1915 to 'converse' from 'inverse' (for compatibility with ZF and some
  1916 literature);
  1917 
  1918 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1919 the well-founded relation;
  1920 
  1921 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1922     Compl A.  The "Compl" syntax remains available as input syntax for this
  1923     release ONLY.
  1924 
  1925 * HOL/Update: new theory of function updates:
  1926     f(a:=b) == %x. if x=a then b else f x
  1927 may also be iterated as in f(a:=b,c:=d,...);
  1928 
  1929 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1930 
  1931 * HOL/List:
  1932   - new function list_update written xs[i:=v] that updates the i-th
  1933     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1934   - new function `upt' written [i..j(] which generates the list
  1935     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1936     bound write [i..j], which is a shorthand for [i..j+1(].
  1937   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1938 
  1939 * HOL/Arith:
  1940   - removed 'pred' (predecessor) function;
  1941   - generalized some theorems about n-1;
  1942   - many new laws about "div" and "mod";
  1943   - new laws about greatest common divisors (see theory ex/Primes);
  1944 
  1945 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1946 instead of "inverse";
  1947 
  1948 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1949   of the multiset ordering;
  1950 
  1951 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1952   (not included by default);
  1953 
  1954 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1955 
  1956 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1957   programs, i.e. different program variables may have different types.
  1958 
  1959 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1960   [previously, this check worked only if the rewrite rule was unconditional]
  1961   Now rew can involve either definitions or equalities (either == or =).
  1962 
  1963 
  1964 *** ZF ***
  1965 
  1966 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1967   only the theorems proved on ZF.ML;
  1968 
  1969 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1970   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1971   disjointness reasoning but breaking a few old proofs.
  1972 
  1973 * ZF/Update: new theory of function updates
  1974     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1975   may also be iterated as in f(a:=b,c:=d,...);
  1976 
  1977 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1978 
  1979 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1980   [previously, this check worked only if the rewrite rule was unconditional]
  1981   Now rew can involve either definitions or equalities (either == or =).
  1982 
  1983 * case_tac provided for compatibility with HOL
  1984     (like the old excluded_middle_tac, but with subgoals swapped)
  1985 
  1986 
  1987 *** Internal programming interfaces ***
  1988 
  1989 * Pure: several new basic modules made available for general use, see
  1990 also src/Pure/README;
  1991 
  1992 * improved the theory data mechanism to support encapsulation (data
  1993 kind name replaced by private Object.kind, acting as authorization
  1994 key); new type-safe user interface via functor TheoryDataFun; generic
  1995 print_data function becomes basically useless;
  1996 
  1997 * removed global_names compatibility flag -- all theory declarations
  1998 are qualified by default;
  1999 
  2000 * module Pure/Syntax now offers quote / antiquote translation
  2001 functions (useful for Hoare logic etc. with implicit dependencies);
  2002 see HOL/ex/Antiquote for an example use;
  2003 
  2004 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2005 cterm -> thm;
  2006 
  2007 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2008 subgoal;
  2009 
  2010 * Display.print_goals function moved to Locale.print_goals;
  2011 
  2012 * standard print function for goals supports current_goals_markers
  2013 variable for marking begin of proof, end of proof, start of goal; the
  2014 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2015 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2016 for example;
  2017 
  2018 
  2019 
  2020 New in Isabelle98 (January 1998)
  2021 --------------------------------
  2022 
  2023 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2024 
  2025 * changed lexical syntax of terms / types: dots made part of long
  2026 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2027 
  2028 * simpset (and claset) reference variable replaced by functions
  2029 simpset / simpset_ref;
  2030 
  2031 * no longer supports theory aliases (via merge) and non-trivial
  2032 implicit merge of thms' signatures;
  2033 
  2034 * most internal names of constants changed due to qualified names;
  2035 
  2036 * changed Pure/Sequence interface (see Pure/seq.ML);
  2037 
  2038 
  2039 *** General Changes ***
  2040 
  2041 * hierachically structured name spaces (for consts, types, axms, thms
  2042 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2043 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2044 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2045 long_names for fully qualified output names; NOTE: ML programs
  2046 (special tactics, packages etc.) referring to internal names may have
  2047 to be adapted to cope with fully qualified names; in case of severe
  2048 backward campatibility problems try setting 'global_names' at compile
  2049 time to have enrything declared within a flat name space; one may also
  2050 fine tune name declarations in theories via the 'global' and 'local'
  2051 section;
  2052 
  2053 * reimplemented the implicit simpset and claset using the new anytype
  2054 data filed in signatures; references simpset:simpset ref etc. are
  2055 replaced by functions simpset:unit->simpset and
  2056 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2057 to patch your ML files accordingly;
  2058 
  2059 * HTML output now includes theory graph data for display with Java
  2060 applet or isatool browser; data generated automatically via isatool
  2061 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2062 
  2063 * defs may now be conditional; improved rewrite_goals_tac to handle
  2064 conditional equations;
  2065 
  2066 * defs now admits additional type arguments, using TYPE('a) syntax;
  2067 
  2068 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2069 creates a new theory node; implicit merge of thms' signatures is
  2070 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2071 transfer:theory->thm->thm in (rare) cases;
  2072 
  2073 * improved handling of draft signatures / theories; draft thms (and
  2074 ctyps, cterms) are automatically promoted to real ones;
  2075 
  2076 * slightly changed interfaces for oracles: admit many per theory, named
  2077 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2078 
  2079 * print_goals: optional output of const types (set show_consts and
  2080 show_types);
  2081 
  2082 * improved output of warnings (###) and errors (***);
  2083 
  2084 * subgoal_tac displays a warning if the new subgoal has type variables;
  2085 
  2086 * removed old README and Makefiles;
  2087 
  2088 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2089 
  2090 * removed obsolete init_pps and init_database;
  2091 
  2092 * deleted the obsolete tactical STATE, which was declared by
  2093     fun STATE tacfun st = tacfun st st;
  2094 
  2095 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2096 (which abbreviates $HOME);
  2097 
  2098 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2099 use isatool fixseq to adapt your ML programs (this works for fully
  2100 qualified references to the Sequence structure only!);
  2101 
  2102 * use_thy no longer requires writable current directory; it always
  2103 reloads .ML *and* .thy file, if either one is out of date;
  2104 
  2105 
  2106 *** Classical Reasoner ***
  2107 
  2108 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2109 tactics that use classical reasoning to simplify a subgoal without
  2110 splitting it into several subgoals;
  2111 
  2112 * Safe_tac: like safe_tac but uses the default claset;
  2113 
  2114 
  2115 *** Simplifier ***
  2116 
  2117 * added simplification meta rules:
  2118     (asm_)(full_)simplify: simpset -> thm -> thm;
  2119 
  2120 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2121 logics (again);
  2122 
  2123 * added prems argument to simplification procedures;
  2124 
  2125 * HOL, FOL, ZF: added infix function `addsplits':
  2126   instead of `<simpset> setloop (split_tac <thms>)'
  2127   you can simply write `<simpset> addsplits <thms>'
  2128 
  2129 
  2130 *** Syntax ***
  2131 
  2132 * TYPE('a) syntax for type reflection terms;
  2133 
  2134 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2135 
  2136 * pretty printer: changed order of mixfix annotation preference (again!);
  2137 
  2138 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2139 
  2140 
  2141 *** HOL ***
  2142 
  2143 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2144   with `addloop' of the simplifier to faciliate case splitting in premises.
  2145 
  2146 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2147 
  2148 * HOL/Auth: new protocol proofs including some for the Internet
  2149   protocol TLS;
  2150 
  2151 * HOL/Map: new theory of `maps' a la VDM;
  2152 
  2153 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2154 cancelling out common nat summands from =, <, <= (in)equalities, or
  2155 differences; simplification procedures nat_cancel_factor for
  2156 cancelling common factor from =, <, <= (in)equalities over natural
  2157 sums; nat_cancel contains both kinds of procedures, it is installed by
  2158 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2159 
  2160 * HOL/simplifier: terms of the form
  2161   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2162   are rewritten to
  2163   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2164   and those of the form
  2165   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2166   are rewritten to
  2167   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2168 
  2169 * HOL/datatype
  2170   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2171 
  2172   P(t_case f1 ... fn x) =
  2173      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2174         ...
  2175        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2176      )
  2177 
  2178   and a theorem `split_t_case_asm' of the form
  2179 
  2180   P(t_case f1 ... fn x) =
  2181     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2182         ...
  2183        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2184      )
  2185   which can be added to a simpset via `addsplits'. The existing theorems
  2186   expand_list_case and expand_option_case have been renamed to
  2187   split_list_case and split_option_case.
  2188 
  2189 * HOL/Arithmetic:
  2190   - `pred n' is automatically converted to `n-1'.
  2191     Users are strongly encouraged not to use `pred' any longer,
  2192     because it will disappear altogether at some point.
  2193   - Users are strongly encouraged to write "0 < n" rather than
  2194     "n ~= 0". Theorems and proof tools have been modified towards this
  2195     `standard'.
  2196 
  2197 * HOL/Lists:
  2198   the function "set_of_list" has been renamed "set" (and its theorems too);
  2199   the function "nth" now takes its arguments in the reverse order and
  2200   has acquired the infix notation "!" as in "xs!n".
  2201 
  2202 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2203 
  2204 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2205   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2206 
  2207 * HOL/record: extensible records with schematic structural subtyping
  2208 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2209 still lacks various theorems and concrete record syntax;
  2210 
  2211 
  2212 *** HOLCF ***
  2213 
  2214 * removed "axioms" and "generated by" sections;
  2215 
  2216 * replaced "ops" section by extended "consts" section, which is capable of
  2217   handling the continuous function space "->" directly;
  2218 
  2219 * domain package:
  2220   . proves theorems immediately and stores them in the theory,
  2221   . creates hierachical name space,
  2222   . now uses normal mixfix annotations (instead of cinfix...),
  2223   . minor changes to some names and values (for consistency),
  2224   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2225   . separator between mutual domain defs: changed "," to "and",
  2226   . improved handling of sort constraints;  now they have to
  2227     appear on the left-hand side of the equations only;
  2228 
  2229 * fixed LAM <x,y,zs>.b syntax;
  2230 
  2231 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2232 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2233 
  2234 
  2235 *** FOL and ZF ***
  2236 
  2237 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2238   with `addloop' of the simplifier to faciliate case splitting in premises.
  2239 
  2240 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2241 in HOL, they strip ALL and --> from proved theorems;
  2242 
  2243 
  2244 
  2245 New in Isabelle94-8 (May 1997)
  2246 ------------------------------
  2247 
  2248 *** General Changes ***
  2249 
  2250 * new utilities to build / run / maintain Isabelle etc. (in parts
  2251 still somewhat experimental); old Makefiles etc. still functional;
  2252 
  2253 * new 'Isabelle System Manual';
  2254 
  2255 * INSTALL text, together with ./configure and ./build scripts;
  2256 
  2257 * reimplemented type inference for greater efficiency, better error
  2258 messages and clean internal interface;
  2259 
  2260 * prlim command for dealing with lots of subgoals (an easier way of
  2261 setting goals_limit);
  2262 
  2263 
  2264 *** Syntax ***
  2265 
  2266 * supports alternative (named) syntax tables (parser and pretty
  2267 printer); internal interface is provided by add_modesyntax(_i);
  2268 
  2269 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2270 be used in conjunction with the Isabelle symbol font; uses the
  2271 "symbols" syntax table;
  2272 
  2273 * added token_translation interface (may translate name tokens in
  2274 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2275 the current print_mode); IMPORTANT: user print translation functions
  2276 are responsible for marking newly introduced bounds
  2277 (Syntax.mark_boundT);
  2278 
  2279 * token translations for modes "xterm" and "xterm_color" that display
  2280 names in bold, underline etc. or colors (which requires a color
  2281 version of xterm);
  2282 
  2283 * infixes may now be declared with names independent of their syntax;
  2284 
  2285 * added typed_print_translation (like print_translation, but may
  2286 access type of constant);
  2287 
  2288 
  2289 *** Classical Reasoner ***
  2290 
  2291 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2292 some limitations.  Blast_tac...
  2293   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2294   + ignores elimination rules that don't have the correct format
  2295         (the conclusion MUST be a formula variable)
  2296   + ignores types, which can make HOL proofs fail
  2297   + rules must not require higher-order unification, e.g. apply_type in ZF
  2298     [message "Function Var's argument not a bound variable" relates to this]
  2299   + its proof strategy is more general but can actually be slower
  2300 
  2301 * substitution with equality assumptions no longer permutes other
  2302 assumptions;
  2303 
  2304 * minor changes in semantics of addafter (now called addaltern); renamed
  2305 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2306 (and access functions for it);
  2307 
  2308 * improved combination of classical reasoner and simplifier:
  2309   + functions for handling clasimpsets
  2310   + improvement of addss: now the simplifier is called _after_ the
  2311     safe steps.
  2312   + safe variant of addss called addSss: uses safe simplifications
  2313     _during_ the safe steps. It is more complete as it allows multiple
  2314     instantiations of unknowns (e.g. with slow_tac).
  2315 
  2316 *** Simplifier ***
  2317 
  2318 * added interface for simplification procedures (functions that
  2319 produce *proven* rewrite rules on the fly, depending on current
  2320 redex);
  2321 
  2322 * ordering on terms as parameter (used for ordered rewriting);
  2323 
  2324 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2325 
  2326 * the solver is now split into a safe and an unsafe part.
  2327 This should be invisible for the normal user, except that the
  2328 functions setsolver and addsolver have been renamed to setSolver and
  2329 addSolver; added safe_asm_full_simp_tac;
  2330 
  2331 
  2332 *** HOL ***
  2333 
  2334 * a generic induction tactic `induct_tac' which works for all datatypes and
  2335 also for type `nat';
  2336 
  2337 * a generic case distinction tactic `exhaust_tac' which works for all
  2338 datatypes and also for type `nat';
  2339 
  2340 * each datatype comes with a function `size';
  2341 
  2342 * patterns in case expressions allow tuple patterns as arguments to
  2343 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2344 
  2345 * primrec now also works with type nat;
  2346 
  2347 * recdef: a new declaration form, allows general recursive functions to be
  2348 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2349 
  2350 * the constant for negation has been renamed from "not" to "Not" to
  2351 harmonize with FOL, ZF, LK, etc.;
  2352 
  2353 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2354 infinite lists;
  2355 
  2356 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2357 
  2358 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2359 problems in commutative rings, using axiomatic type classes for + and *;
  2360 
  2361 * more examples in HOL/MiniML and HOL/Auth;
  2362 
  2363 * more default rewrite rules for quantifiers, union/intersection;
  2364 
  2365 * a new constant `arbitrary == @x.False';
  2366 
  2367 * HOLCF/IOA replaces old HOL/IOA;
  2368 
  2369 * HOLCF changes: derived all rules and arities
  2370   + axiomatic type classes instead of classes
  2371   + typedef instead of faking type definitions
  2372   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2373   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2374   + eliminated the types void, one, tr
  2375   + use unit lift and bool lift (with translations) instead of one and tr
  2376   + eliminated blift from Lift3.thy (use Def instead of blift)
  2377   all eliminated rules are derived as theorems --> no visible changes ;
  2378 
  2379 
  2380 *** ZF ***
  2381 
  2382 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2383 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2384 as ZF_cs addSIs [equalityI];
  2385 
  2386 
  2387 
  2388 New in Isabelle94-7 (November 96)
  2389 ---------------------------------
  2390 
  2391 * allowing negative levels (as offsets) in prlev and choplev;
  2392 
  2393 * super-linear speedup for large simplifications;
  2394 
  2395 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2396 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2397 FAIL); can suppress it using the command Delsimps (ex_simps @
  2398 all_simps); De Morgan laws are also now included, by default;
  2399 
  2400 * improved printing of ==>  :  ~:
  2401 
  2402 * new object-logic "Sequents" adds linear logic, while replacing LK
  2403 and Modal (thanks to Sara Kalvala);
  2404 
  2405 * HOL/Auth: correctness proofs for authentication protocols;
  2406 
  2407 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2408 examples on HOL/Auth);
  2409 
  2410 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2411 the rewriter and classical reasoner simultaneously;
  2412 
  2413 * function uresult no longer returns theorems in "standard" format;
  2414 regain previous version by: val uresult = standard o uresult;
  2415 
  2416 
  2417 
  2418 New in Isabelle94-6
  2419 -------------------
  2420 
  2421 * oracles -- these establish an interface between Isabelle and trusted
  2422 external reasoners, which may deliver results as theorems;
  2423 
  2424 * proof objects (in particular record all uses of oracles);
  2425 
  2426 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2427 
  2428 * "constdefs" section in theory files;
  2429 
  2430 * "primrec" section (HOL) no longer requires names;
  2431 
  2432 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2433 
  2434 
  2435 
  2436 New in Isabelle94-5
  2437 -------------------
  2438 
  2439 * reduced space requirements;
  2440 
  2441 * automatic HTML generation from theories;
  2442 
  2443 * theory files no longer require "..." (quotes) around most types;
  2444 
  2445 * new examples, including two proofs of the Church-Rosser theorem;
  2446 
  2447 * non-curried (1994) version of HOL is no longer distributed;
  2448 
  2449 
  2450 
  2451 New in Isabelle94-4
  2452 -------------------
  2453 
  2454 * greatly reduced space requirements;
  2455 
  2456 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2457 
  2458 * searchable theorem database (see the section "Retrieving theorems" on
  2459 page 8 of the Reference Manual);
  2460 
  2461 * new examples, including Grabczewski's monumental case study of the
  2462 Axiom of Choice;
  2463 
  2464 * The previous version of HOL renamed to Old_HOL;
  2465 
  2466 * The new version of HOL (previously called CHOL) uses a curried syntax
  2467 for functions.  Application looks like f a b instead of f(a,b);
  2468 
  2469 * Mutually recursive inductive definitions finally work in HOL;
  2470 
  2471 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2472 translates to the operator "split";
  2473 
  2474 
  2475 
  2476 New in Isabelle94-3
  2477 -------------------
  2478 
  2479 * new infix operator, addss, allowing the classical reasoner to
  2480 perform simplification at each step of its search.  Example:
  2481         fast_tac (cs addss ss)
  2482 
  2483 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2484 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2485 look like (a,b) instead of <a,b>;
  2486 
  2487 * PLEASE NOTE: CHOL will eventually replace HOL!
  2488 
  2489 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2490 It translates to the operator "split".  A new theory of integers is available;
  2491 
  2492 * In ZF, integer numerals now denote two's-complement binary integers.
  2493 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2494 
  2495 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2496 of the Axiom of Choice;
  2497 
  2498 
  2499 
  2500 New in Isabelle94-2
  2501 -------------------
  2502 
  2503 * Significantly faster resolution;
  2504 
  2505 * the different sections in a .thy file can now be mixed and repeated
  2506 freely;
  2507 
  2508 * Database of theorems for FOL, HOL and ZF.  New
  2509 commands including qed, qed_goal and bind_thm store theorems in the database.
  2510 
  2511 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2512 a given theory (thms_of), or find out what theory a theorem was proved in
  2513 (theory_of_thm);
  2514 
  2515 * Bugs fixed in the inductive definition and datatype packages;
  2516 
  2517 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2518 and HOL_dup_cs obsolete;
  2519 
  2520 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2521 have been removed;
  2522 
  2523 * Simpler definition of function space in ZF;
  2524 
  2525 * new results about cardinal and ordinal arithmetic in ZF;
  2526 
  2527 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2528 types;
  2529 
  2530 
  2531 $Id$