NEWS
author kleing
Mon Dec 29 06:49:26 2003 +0100 (2003-12-29)
changeset 14333 14f29eb097a3
parent 14285 92ed032e83a1
child 14361 ad2f5da643b4
permissions -rw-r--r--
\<^bsub> .. \<^esub>
     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: Using new Isar command "finalconsts" (or the ML functions
    33   Theory.add_finals or Theory.add_finals_i) it is now possible to
    34   declare constants "final", which prevents their being given a definition
    35   later.  It is useful for constants whose behaviour is fixed axiomatically
    36   rather than definitionally, such as the meta-logic connectives.
    37 
    38 *** Isar ***
    39 
    40 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    41   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    42     locales are no longer forced to write Isar proof scripts.
    43     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    44     emulations.
    45   - INCOMPATIBILITY: names of variables to be instantiated may no
    46     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    47     This is consistent with the instantiation attribute "where".
    48 
    49 * Attributes "where" and "of":
    50   - Now take type variables of instantiated theorem into account when reading
    51     the instantiation string.  This fixes a bug that caused instantiated
    52     theorems to have too special types in some circumstances.
    53   - "where" permits explicit instantiations of type variables.
    54 
    55 * Calculation commands "moreover" and "also":
    56   Do not reset facts ("this") any more.
    57 
    58 * Locales:
    59   - Goal statements involving the context element "includes" no longer
    60     generate theorems with internal delta predicates (those ending on
    61     "_axioms") in the premise.
    62     Resolve particular premise with <locale>.intro to obtain old form.
    63   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    64     specification and "includes" elements in goal statement.
    65   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    66     [intro?] and [elim?] (respectively) by default.
    67 
    68 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    69   (Isar) contexts.
    70 
    71 *** HOL ***
    72 
    73 * Records:
    74   - Record types are now by default printed with their type abbreviation
    75     instead of the list of all field types. This can be configured via
    76     the reference "print_record_type_abbr".
    77   - Simproc "record_upd_simproc" for simplification of multiple updates added 
    78     (not enabled by default).
    79   - Tactic "record_split_simp_tac" to split and simplify records added.
    80  
    81 * 'specification' command added, allowing for definition by
    82   specification.  There is also an 'ax_specification' command that
    83   introduces the new constants axiomatically.
    84 
    85 * SET-Protocol: formalization and verification of the SET protocol suite;
    86 
    87 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
    88  defintions, thanks to Sava Krsti\'{c} and John Matthews.
    89 
    90 New in Isabelle2003 (May 2003)
    91 --------------------------------
    92 
    93 *** General ***
    94 
    95 * Provers/simplifier:
    96 
    97   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    98     Assumptions are now subject to complete mutual simplification,
    99     not just from left to right. The simplifier now preserves
   100     the order of assumptions.
   101 
   102     Potential INCOMPATIBILITY:
   103 
   104     -- simp sometimes diverges where the old version did
   105        not, e.g. invoking simp on the goal
   106 
   107         [| P (f x); y = x; f x = f y |] ==> Q
   108 
   109        now gives rise to the infinite reduction sequence
   110 
   111         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   112 
   113        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   114        kind of problem.
   115 
   116     -- Tactics combining classical reasoner and simplification (such as auto)
   117        are also affected by this change, because many of them rely on
   118        simp. They may sometimes diverge as well or yield a different numbers
   119        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   120        in case of problems. Sometimes subsequent calls to the classical
   121        reasoner will fail because a preceeding call to the simplifier too
   122        eagerly simplified the goal, e.g. deleted redundant premises.
   123 
   124   - The simplifier trace now shows the names of the applied rewrite rules
   125 
   126   - You can limit the number of recursive invocations of the simplifier
   127     during conditional rewriting (where the simplifie tries to solve the
   128     conditions before applying the rewrite rule):
   129     ML "simp_depth_limit := n"
   130     where n is an integer. Thus you can force termination where previously
   131     the simplifier would diverge.
   132 
   133   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   134 
   135   - No longer aborts on failed congruence proof.  Instead, the
   136     congruence is ignored.
   137 
   138 * Pure: New generic framework for extracting programs from constructive
   139   proofs. See HOL/Extraction.thy for an example instantiation, as well
   140   as HOL/Extraction for some case studies.
   141 
   142 * Pure: The main goal of the proof state is no longer shown by default, only
   143 the subgoals. This behaviour is controlled by a new flag.
   144    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   145 (ML: Proof.show_main_goal).
   146 
   147 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   148 rules whose conclusion matches subgoal 1:
   149       PG menu: Isabelle/Isar -> Show me -> matching rules
   150 The rules are ordered by how closely they match the subgoal.
   151 In particular, rules that solve a subgoal outright are displayed first
   152 (or rather last, the way they are printed).
   153 (ML: ProofGeneral.print_intros())
   154 
   155 * Pure: New flag trace_unify_fail causes unification to print
   156 diagnostic information (PG: in trace buffer) when it fails. This is
   157 useful for figuring out why single step proofs like rule, erule or
   158 assumption failed.
   159 
   160 * Pure: Locale specifications now produce predicate definitions
   161 according to the body of text (covering assumptions modulo local
   162 definitions); predicate "loc_axioms" covers newly introduced text,
   163 while "loc" is cumulative wrt. all included locale expressions; the
   164 latter view is presented only on export into the global theory
   165 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   166 on the old view without predicates;
   167 
   168 * Pure: predefined locales "var" and "struct" are useful for sharing
   169 parameters (as in CASL, for example); just specify something like
   170 ``var x + var y + struct M'' as import;
   171 
   172 * Pure: improved thms_containing: proper indexing of facts instead of
   173 raw theorems; check validity of results wrt. current name space;
   174 include local facts of proof configuration (also covers active
   175 locales), cover fixed variables in index; may use "_" in term
   176 specification; an optional limit for the number of printed facts may
   177 be given (the default is 40);
   178 
   179 * Pure: disallow duplicate fact bindings within new-style theory files
   180 (batch-mode only);
   181 
   182 * Provers: improved induct method: assumptions introduced by case
   183 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   184 the goal statement); "foo" still refers to all facts collectively;
   185 
   186 * Provers: the function blast.overloaded has been removed: all constants
   187 are regarded as potentially overloaded, which improves robustness in exchange
   188 for slight decrease in efficiency;
   189 
   190 * Provers/linorder: New generic prover for transitivity reasoning over
   191 linear orders.  Note: this prover is not efficient!
   192 
   193 * Isar: preview of problems to finish 'show' now produce an error
   194 rather than just a warning (in interactive mode);
   195 
   196 
   197 *** HOL ***
   198 
   199 * arith(_tac)
   200 
   201  - Produces a counter example if it cannot prove a goal.
   202    Note that the counter example may be spurious if the goal is not a formula
   203    of quantifier-free linear arithmetic.
   204    In ProofGeneral the counter example appears in the trace buffer.
   205 
   206  - Knows about div k and mod k where k is a numeral of type nat or int.
   207 
   208  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   209    linear arithmetic fails. This takes account of quantifiers and divisibility.
   210    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   211 
   212 * simp's arithmetic capabilities have been enhanced a bit: it now
   213 takes ~= in premises into account (by performing a case split);
   214 
   215 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   216 are distributed over a sum of terms;
   217 
   218 * New tactic "trans_tac" and method "trans" instantiate
   219 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   220 "<=", "<" and "="). 
   221 
   222 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   223 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   224 
   225 * 'typedef' command has new option "open" to suppress the set
   226 definition;
   227 
   228 * functions Min and Max on finite sets have been introduced (theory
   229 Finite_Set);
   230 
   231 * attribute [symmetric] now works for relations as well; it turns
   232 (x,y) : R^-1 into (y,x) : R, and vice versa;
   233 
   234 * induct over a !!-quantified statement (say !!x1..xn):
   235   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   236 
   237 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   238 %x. None. Warning: empty_def now refers to the previously hidden definition
   239 of the empty set.
   240 
   241 * Algebra: formalization of classical algebra.  Intended as base for
   242 any algebraic development in Isabelle.  Currently covers group theory
   243 (up to Sylow's theorem) and ring theory (Universal Property of
   244 Univariate Polynomials).  Contributions welcome;
   245 
   246 * GroupTheory: deleted, since its material has been moved to Algebra;
   247 
   248 * Complex: new directory of the complex numbers with numeric constants, 
   249 nonstandard complex numbers, and some complex analysis, standard and 
   250 nonstandard (Jacques Fleuriot);
   251 
   252 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   253 
   254 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   255 Fleuriot);
   256 
   257 * Real/HahnBanach: updated and adapted to locales;
   258 
   259 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   260 Gray and Kramer);
   261 
   262 * UNITY: added the Meier-Sanders theory of progress sets;
   263 
   264 * MicroJava: bytecode verifier and lightweight bytecode verifier
   265 as abstract algorithms, instantiated to the JVM;
   266 
   267 * Bali: Java source language formalization. Type system, operational
   268 semantics, axiomatic semantics. Supported language features:
   269 classes, interfaces, objects,virtual methods, static methods,
   270 static/instance fields, arrays, access modifiers, definite
   271 assignment, exceptions.
   272 
   273 
   274 *** ZF ***
   275 
   276 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   277 universe, etc.);
   278 
   279 * Main ZF: virtually all theories converted to new-style format;
   280 
   281 
   282 *** ML ***
   283 
   284 * Pure: Tactic.prove provides sane interface for internal proofs;
   285 omits the infamous "standard" operation, so this is more appropriate
   286 than prove_goalw_cterm in many situations (e.g. in simprocs);
   287 
   288 * Pure: improved error reporting of simprocs;
   289 
   290 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   291 up simprocs;
   292 
   293 
   294 *** Document preparation ***
   295 
   296 * uses \par instead of \\ for line breaks in theory text. This may
   297 shift some page breaks in large documents. To get the old behaviour
   298 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   299 
   300 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   301 other packages
   302 
   303 * \<euro> now needs package babel/greek instead of marvosym (which
   304 broke \Rightarrow)
   305 
   306 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   307 textcomp package)
   308 
   309 
   310 New in Isabelle2002 (March 2002)
   311 --------------------------------
   312 
   313 *** Document preparation ***
   314 
   315 * greatly simplified document preparation setup, including more
   316 graceful interpretation of isatool usedir -i/-d/-D options, and more
   317 instructive isatool mkdir; users should basically be able to get
   318 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   319 users may run a separate document processing stage manually like this:
   320 "isatool usedir -D output HOL Test && isatool document Test/output";
   321 
   322 * theory dependency graph may now be incorporated into documents;
   323 isatool usedir -g true will produce session_graph.eps/.pdf for use
   324 with \includegraphics of LaTeX;
   325 
   326 * proper spacing of consecutive markup elements, especially text
   327 blocks after section headings;
   328 
   329 * support bold style (for single symbols only), input syntax is like
   330 this: "\<^bold>\<alpha>" or "\<^bold>A";
   331 
   332 * \<bullet> is now output as bold \cdot by default, which looks much
   333 better in printed text;
   334 
   335 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   336 note that these symbols are currently unavailable in Proof General /
   337 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   338 
   339 * isatool latex no longer depends on changed TEXINPUTS, instead
   340 isatool document copies the Isabelle style files to the target
   341 location;
   342 
   343 
   344 *** Isar ***
   345 
   346 * Pure/Provers: improved proof by cases and induction;
   347   - 'case' command admits impromptu naming of parameters (such as
   348     "case (Suc n)");
   349   - 'induct' method divinates rule instantiation from the inductive
   350     claim; no longer requires excessive ?P bindings for proper
   351     instantiation of cases;
   352   - 'induct' method properly enumerates all possibilities of set/type
   353     rules; as a consequence facts may be also passed through *type*
   354     rules without further ado;
   355   - 'induct' method now derives symbolic cases from the *rulified*
   356     rule (before it used to rulify cases stemming from the internal
   357     atomized version); this means that the context of a non-atomic
   358     statement becomes is included in the hypothesis, avoiding the
   359     slightly cumbersome show "PROP ?case" form;
   360   - 'induct' may now use elim-style induction rules without chaining
   361     facts, using ``missing'' premises from the goal state; this allows
   362     rules stemming from inductive sets to be applied in unstructured
   363     scripts, while still benefitting from proper handling of non-atomic
   364     statements; NB: major inductive premises need to be put first, all
   365     the rest of the goal is passed through the induction;
   366   - 'induct' proper support for mutual induction involving non-atomic
   367     rule statements (uses the new concept of simultaneous goals, see
   368     below);
   369   - append all possible rule selections, but only use the first
   370     success (no backtracking);
   371   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   372   - undeclared rule case names default to numbers 1, 2, 3, ...;
   373   - added 'print_induct_rules' (covered by help item in recent Proof
   374     General versions);
   375   - moved induct/cases attributes to Pure, methods to Provers;
   376   - generic method setup instantiated for FOL and HOL;
   377 
   378 * Pure: support multiple simultaneous goal statements, for example
   379 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   380 meta-level mechanism, this acts as if several individual goals had
   381 been stated separately; in particular common proof methods need to be
   382 repeated in order to cover all claims; note that a single elimination
   383 step is *not* sufficient to establish the two conjunctions, so this
   384 fails:
   385 
   386   assume "A & B" then have A and B ..   (*".." fails*)
   387 
   388 better use "obtain" in situations as above; alternative refer to
   389 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   390 
   391 * Pure: proper integration with ``locales''; unlike the original
   392 version by Florian Kammüller, Isar locales package high-level proof
   393 contexts rather than raw logical ones (e.g. we admit to include
   394 attributes everywhere); operations on locales include merge and
   395 rename; support for implicit arguments (``structures''); simultaneous
   396 type-inference over imports and text; see also HOL/ex/Locales.thy for
   397 some examples;
   398 
   399 * Pure: the following commands have been ``localized'', supporting a
   400 target locale specification "(in name)": 'lemma', 'theorem',
   401 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   402 stored both within the locale and at the theory level (exported and
   403 qualified by the locale name);
   404 
   405 * Pure: theory goals may now be specified in ``long'' form, with
   406 ad-hoc contexts consisting of arbitrary locale elements. for example
   407 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   408 definitions may be given, too); the result is a meta-level rule with
   409 the context elements being discharged in the obvious way;
   410 
   411 * Pure: new proof command 'using' allows to augment currently used
   412 facts after a goal statement ('using' is syntactically analogous to
   413 'apply', but acts on the goal's facts only); this allows chained facts
   414 to be separated into parts given before and after a claim, as in
   415 ``from a and b have C using d and e <proof>'';
   416 
   417 * Pure: renamed "antecedent" case to "rule_context";
   418 
   419 * Pure: new 'judgment' command records explicit information about the
   420 object-logic embedding (used by several tools internally); no longer
   421 use hard-wired "Trueprop";
   422 
   423 * Pure: added 'corollary' command;
   424 
   425 * Pure: fixed 'token_translation' command;
   426 
   427 * Pure: removed obsolete 'exported' attribute;
   428 
   429 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   430 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   431 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   432 
   433 * Pure: method 'atomize' presents local goal premises as object-level
   434 statements (atomic meta-level propositions); setup controlled via
   435 rewrite rules declarations of 'atomize' attribute; example
   436 application: 'induct' method with proper rule statements in improper
   437 proof *scripts*;
   438 
   439 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   440 now consider the syntactic context of assumptions, giving a better
   441 chance to get type-inference of the arguments right (this is
   442 especially important for locales);
   443 
   444 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   445 mode;
   446 
   447 * Pure/obtain: the formal conclusion "thesis", being marked as
   448 ``internal'', may no longer be reference directly in the text;
   449 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   450 situations;
   451 
   452 * Pure: generic 'sym' attribute which declares a rule both as pure
   453 'elim?' and for the 'symmetric' operation;
   454 
   455 * Pure: marginal comments ``--'' may now occur just anywhere in the
   456 text; the fixed correlation with particular command syntax has been
   457 discontinued;
   458 
   459 * Pure: new method 'rules' is particularly well-suited for proof
   460 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   461 but often produces more compact proof terms with less detours;
   462 
   463 * Pure/Provers/classical: simplified integration with pure rule
   464 attributes and methods; the classical "intro?/elim?/dest?"
   465 declarations coincide with the pure ones; the "rule" method no longer
   466 includes classically swapped intros; "intro" and "elim" methods no
   467 longer pick rules from the context; also got rid of ML declarations
   468 AddXIs/AddXEs/AddXDs; all of this has some potential for
   469 INCOMPATIBILITY;
   470 
   471 * Provers/classical: attribute 'swapped' produces classical inversions
   472 of introduction rules;
   473 
   474 * Provers/simplifier: 'simplified' attribute may refer to explicit
   475 rules instead of full simplifier context; 'iff' attribute handles
   476 conditional rules;
   477 
   478 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   479 
   480 * HOL: 'recdef' now fails on unfinished automated proofs, use
   481 "(permissive)" option to recover old behavior;
   482 
   483 * HOL: 'inductive' no longer features separate (collective) attributes
   484 for 'intros' (was found too confusing);
   485 
   486 * HOL: properly declared induction rules less_induct and
   487 wf_induct_rule;
   488 
   489 
   490 *** HOL ***
   491 
   492 * HOL: moved over to sane numeral syntax; the new policy is as
   493 follows:
   494 
   495   - 0 and 1 are polymorphic constants, which are defined on any
   496   numeric type (nat, int, real etc.);
   497 
   498   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   499   binary representation internally;
   500 
   501   - type nat has special constructor Suc, and generally prefers Suc 0
   502   over 1::nat and Suc (Suc 0) over 2::nat;
   503 
   504 This change may cause significant problems of INCOMPATIBILITY; here
   505 are some hints on converting existing sources:
   506 
   507   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   508   entities, so expressions involving "-" (unary or binary minus) need
   509   to be spaced properly;
   510 
   511   - existing occurrences of "1" may need to be constraint "1::nat" or
   512   even replaced by Suc 0; similar for old "2";
   513 
   514   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   515 
   516   - remove all special provisions on numerals in proofs;
   517 
   518 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   519 representation (depends on bin_arith_simps in the default context);
   520 
   521 * HOL: symbolic syntax for x^2 (numeral 2);
   522 
   523 * HOL: the class of all HOL types is now called "type" rather than
   524 "term"; INCOMPATIBILITY, need to adapt references to this type class
   525 in axclass/classes, instance/arities, and (usually rare) occurrences
   526 in typings (of consts etc.); internally the class is called
   527 "HOL.type", ML programs should refer to HOLogic.typeS;
   528 
   529 * HOL/record package improvements:
   530   - new derived operations "fields" to build a partial record section,
   531     "extend" to promote a fixed record to a record scheme, and
   532     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   533     declared as simp by default;
   534   - shared operations ("more", "fields", etc.) now need to be always
   535     qualified) --- potential INCOMPATIBILITY;
   536   - removed "make_scheme" operations (use "make" with "extend") --
   537     INCOMPATIBILITY;
   538   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   539   - provides cases/induct rules for use with corresponding Isar
   540     methods (for concrete records, record schemes, concrete more
   541     parts, and schematic more parts -- in that order);
   542   - internal definitions directly based on a light-weight abstract
   543     theory of product types over typedef rather than datatype;
   544 
   545 * HOL: generic code generator for generating executable ML code from
   546 specifications; specific support for HOL constructs such as inductive
   547 datatypes and sets, as well as recursive functions; can be invoked
   548 via 'generate_code' theory section;
   549 
   550 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   551 
   552 * HOL: consolidated and renamed several theories.  In particular:
   553 	Ord.thy has been absorbed into HOL.thy
   554 	String.thy has been absorbed into List.thy
   555  
   556 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   557 (beware of argument permutation!);
   558 
   559 * HOL: linorder_less_split superseded by linorder_cases;
   560 
   561 * HOL/List: "nodups" renamed to "distinct";
   562 
   563 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   564 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   565   - Ex_def has changed, now need to use some_eq_ex
   566 
   567 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   568 in this (rare) case use:
   569 
   570   delSWrapper "split_all_tac"
   571   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   572 
   573 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   574 MAY FAIL;
   575 
   576 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   577 Isabelle's type classes, ^ on functions and relations has too general
   578 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   579 necessary to attach explicit type constraints;
   580 
   581 * HOL/Relation: the prefix name of the infix "O" has been changed from
   582 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   583 renamed accordingly (eg "compI" -> "rel_compI").
   584 
   585 * HOL: syntax translations now work properly with numerals and records
   586 expressions;
   587 
   588 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   589 of "lam" -- INCOMPATIBILITY;
   590 
   591 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   592 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   593 renamed "Product_Type.unit";
   594 
   595 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   596 
   597 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   598 the "cases" method);
   599 
   600 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   601 Florian Kammüller);
   602 
   603 * HOL/IMP: updated and converted to new-style theory format; several
   604 parts turned into readable document, with proper Isar proof texts and
   605 some explanations (by Gerwin Klein);
   606 
   607 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   608 
   609 * HOL-Hyperreal is now a logic image;
   610 
   611 
   612 *** HOLCF ***
   613 
   614 * Isar: consts/constdefs supports mixfix syntax for continuous
   615 operations;
   616 
   617 * Isar: domain package adapted to new-style theory format, e.g. see
   618 HOLCF/ex/Dnat.thy;
   619 
   620 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   621 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   622 lift.induct_tac, always use UU instead of Undef;
   623 
   624 * HOLCF/IMP: updated and converted to new-style theory;
   625 
   626 
   627 *** ZF ***
   628 
   629 * Isar: proper integration of logic-specific tools and packages,
   630 including theory commands '(co)inductive', '(co)datatype',
   631 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   632 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   633 
   634 * theory Main no longer includes AC; for the Axiom of Choice, base
   635 your theory on Main_ZFC;
   636 
   637 * the integer library now covers quotients and remainders, with many
   638 laws relating division to addition, multiplication, etc.;
   639 
   640 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   641 typeless version of the formalism;
   642 
   643 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   644 format;
   645 
   646 * ZF/Induct: new directory for examples of inductive definitions,
   647 including theory Multiset for multiset orderings; converted to
   648 new-style theory format;
   649 
   650 * ZF: many new theorems about lists, ordinals, etc.;
   651 
   652 
   653 *** General ***
   654 
   655 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   656 variable proof controls level of detail: 0 = no proofs (only oracle
   657 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   658 also ref manual for further ML interfaces;
   659 
   660 * Pure/axclass: removed obsolete ML interface
   661 goal_subclass/goal_arity;
   662 
   663 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   664 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   665 separate tokens, so expressions involving minus need to be spaced
   666 properly;
   667 
   668 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   669 rather than "infixl" or "infixr";
   670 
   671 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   672 sort constraint specifications in type inference; e.g. "x::_::foo"
   673 ensures that the type of "x" is of sort "foo" (but not necessarily a
   674 type variable);
   675 
   676 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   677 control output of nested => (types); the default behavior is
   678 "type_brackets";
   679 
   680 * Pure/syntax: builtin parse translation for "_constify" turns valued
   681 tokens into AST constants;
   682 
   683 * Pure/syntax: prefer later declarations of translations and print
   684 translation functions; potential INCOMPATIBILITY: need to reverse
   685 multiple declarations for same syntax element constant;
   686 
   687 * Pure/show_hyps reset by default (in accordance to existing Isar
   688 practice);
   689 
   690 * Provers/classical: renamed addaltern to addafter, addSaltern to
   691 addSafter;
   692 
   693 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   694 as well;
   695 
   696 * system: tested support for MacOS X; should be able to get Isabelle +
   697 Proof General to work in a plain Terminal after installing Poly/ML
   698 (e.g. from the Isabelle distribution area) and GNU bash alone
   699 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   700 support requires further installations, e.g. from
   701 http://fink.sourceforge.net/);
   702 
   703 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   704 
   705 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   706 of 40 MB), cf. ML_OPTIONS;
   707 
   708 * system: Proof General keywords specification is now part of the
   709 Isabelle distribution (see etc/isar-keywords.el);
   710 
   711 * system: support for persistent Proof General sessions (refrain from
   712 outdating all loaded theories on startup); user may create writable
   713 logic images like this: ``isabelle -q HOL Test'';
   714 
   715 * system: smart selection of Isabelle process versus Isabelle
   716 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   717 run both "isabelle" and "Isabelle" even if file names are badly
   718 damaged (executable inspects the case of the first letter of its own
   719 name); added separate "isabelle-process" and "isabelle-interface";
   720 
   721 * system: refrain from any attempt at filtering input streams; no
   722 longer support ``8bit'' encoding of old isabelle font, instead proper
   723 iso-latin characters may now be used; the related isatools
   724 "symbolinput" and "nonascii" have disappeared as well;
   725 
   726 * system: removed old "xterm" interface (the print modes "xterm" and
   727 "xterm_color" are still available for direct use in a suitable
   728 terminal);
   729 
   730 
   731 
   732 New in Isabelle99-2 (February 2001)
   733 -----------------------------------
   734 
   735 *** Overview of INCOMPATIBILITIES ***
   736 
   737 * HOL: please note that theories in the Library and elsewhere often use the
   738 new-style (Isar) format; to refer to their theorems in an ML script you must
   739 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   740 
   741 * HOL: inductive package no longer splits induction rule aggressively,
   742 but only as far as specified by the introductions given; the old
   743 format may be recovered via ML function complete_split_rule or attribute
   744 'split_rule (complete)';
   745 
   746 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   747 gfp_Tarski to gfp_unfold;
   748 
   749 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   750 
   751 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   752 relation); infix "^^" has been renamed "``"; infix "``" has been
   753 renamed "`"; "univalent" has been renamed "single_valued";
   754 
   755 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   756 operation;
   757 
   758 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   759 
   760 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   761 
   762 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   763 consequence, it is no longer monotonic wrt. the local goal context
   764 (which is now passed through the inductive cases);
   765 
   766 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   767 \<gg> to \<ggreater>;
   768 
   769 
   770 *** Document preparation ***
   771 
   772 * \isabellestyle{NAME} selects version of Isabelle output (currently
   773 available: are "it" for near math-mode best-style output, "sl" for
   774 slanted text style, and "tt" for plain type-writer; if no
   775 \isabellestyle command is given, output is according to slanted
   776 type-writer);
   777 
   778 * support sub/super scripts (for single symbols only), input syntax is
   779 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   780 
   781 * some more standard symbols; see Appendix A of the system manual for
   782 the complete list of symbols defined in isabellesym.sty;
   783 
   784 * improved isabelle style files; more abstract symbol implementation
   785 (should now use \isamath{...} and \isatext{...} in custom symbol
   786 definitions);
   787 
   788 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   789 state; Note that presentation of goal states does not conform to
   790 actual human-readable proof documents.  Please do not include goal
   791 states into document output unless you really know what you are doing!
   792 
   793 * proper indentation of antiquoted output with proportional LaTeX
   794 fonts;
   795 
   796 * no_document ML operator temporarily disables LaTeX document
   797 generation;
   798 
   799 * isatool unsymbolize tunes sources for plain ASCII communication;
   800 
   801 
   802 *** Isar ***
   803 
   804 * Pure: Isar now suffers initial goal statements to contain unbound
   805 schematic variables (this does not conform to actual readable proof
   806 documents, due to unpredictable outcome and non-compositional proof
   807 checking); users who know what they are doing may use schematic goals
   808 for Prolog-style synthesis of proven results;
   809 
   810 * Pure: assumption method (an implicit finishing) now handles actual
   811 rules as well;
   812 
   813 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   814 initial goal, declare "that" only as Pure intro (only for single
   815 steps); the "that" rule assumption may now be involved in implicit
   816 finishing, thus ".." becomes a feasible for trivial obtains;
   817 
   818 * Pure: default proof step now includes 'intro_classes'; thus trivial
   819 instance proofs may be performed by "..";
   820 
   821 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   822 statements as well;
   823 
   824 * Pure: more robust selection of calculational rules;
   825 
   826 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   827 rule (as well as the assumption rule);
   828 
   829 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   830 lemmas, using the graph browser tool;
   831 
   832 * Pure: predict failure of "show" in interactive mode;
   833 
   834 * Pure: 'thms_containing' now takes actual terms as arguments;
   835 
   836 * HOL: improved method 'induct' --- now handles non-atomic goals
   837 (potential INCOMPATIBILITY); tuned error handling;
   838 
   839 * HOL: cases and induct rules now provide explicit hints about the
   840 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   841 any remaining facts are inserted into the goal verbatim;
   842 
   843 * HOL: local contexts (aka cases) may now contain term bindings as
   844 well; the 'cases' and 'induct' methods new provide a ?case binding for
   845 the result to be shown in each case;
   846 
   847 * HOL: added 'recdef_tc' command;
   848 
   849 * isatool convert assists in eliminating legacy ML scripts;
   850 
   851 
   852 *** HOL ***
   853 
   854 * HOL/Library: a collection of generic theories to be used together
   855 with main HOL; the theory loader path already includes this directory
   856 by default; the following existing theories have been moved here:
   857 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   858 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   859 
   860 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   861 modelling and verification task performed in Isabelle/HOL +
   862 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   863 
   864 * HOL/Algebra: special summation operator SUM no longer exists, it has
   865 been replaced by setsum; infix 'assoc' now has priority 50 (like
   866 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   867 'domain', this makes the theory consistent with mathematical
   868 literature;
   869 
   870 * HOL basics: added overloaded operations "inverse" and "divide"
   871 (infix "/"), syntax for generic "abs" operation, generic summation
   872 operator \<Sum>;
   873 
   874 * HOL/typedef: simplified package, provide more useful rules (see also
   875 HOL/subset.thy);
   876 
   877 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   878 now expressed as a proper nested rule (old-style tactic scripts may
   879 require atomize_strip_tac to cope with non-atomic premises);
   880 
   881 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   882 to "split_conv" (old name still available for compatibility);
   883 
   884 * HOL: improved concrete syntax for strings (e.g. allows translation
   885 rules with string literals);
   886 
   887 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   888  and Fleuriot's mechanization of analysis, including the transcendental
   889  functions for the reals;
   890 
   891 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   892 
   893 
   894 *** CTT ***
   895 
   896 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   897 "lam" is displayed as TWO lambda-symbols
   898 
   899 * CTT: theory Main now available, containing everything (that is, Bool
   900 and Arith);
   901 
   902 
   903 *** General ***
   904 
   905 * Pure: the Simplifier has been implemented properly as a derived rule
   906 outside of the actual kernel (at last!); the overall performance
   907 penalty in practical applications is about 50%, while reliability of
   908 the Isabelle inference kernel has been greatly improved;
   909 
   910 * print modes "brackets" and "no_brackets" control output of nested =>
   911 (types) and ==> (props); the default behaviour is "brackets";
   912 
   913 * Provers: fast_tac (and friends) now handle actual object-logic rules
   914 as assumptions as well;
   915 
   916 * system: support Poly/ML 4.0;
   917 
   918 * system: isatool install handles KDE version 1 or 2;
   919 
   920 
   921 
   922 New in Isabelle99-1 (October 2000)
   923 ----------------------------------
   924 
   925 *** Overview of INCOMPATIBILITIES ***
   926 
   927 * HOL: simplification of natural numbers is much changed; to partly
   928 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   929 issue the following ML commands:
   930 
   931   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   932   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   933 
   934 * HOL: simplification no longer dives into case-expressions; this is
   935 controlled by "t.weak_case_cong" for each datatype t;
   936 
   937 * HOL: nat_less_induct renamed to less_induct;
   938 
   939 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   940 fixsome to patch .thy and .ML sources automatically;
   941 
   942   select_equality  -> some_equality
   943   select_eq_Ex     -> some_eq_ex
   944   selectI2EX       -> someI2_ex
   945   selectI2         -> someI2
   946   selectI          -> someI
   947   select1_equality -> some1_equality
   948   Eps_sym_eq       -> some_sym_eq_trivial
   949   Eps_eq           -> some_eq_trivial
   950 
   951 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   952 
   953 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   954 instead);
   955 
   956 * HOL: the recursion equations generated by 'recdef' are now called
   957 f.simps instead of f.rules;
   958 
   959 * HOL: qed_spec_mp now also handles bounded ALL as well;
   960 
   961 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   962 sometimes be needed;
   963 
   964 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   965 
   966 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   967 
   968 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   969 product is now "<*>" instead of "Times"; the lexicographic product is
   970 now "<*lex*>" instead of "**";
   971 
   972 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   973 of main HOL, but was unused); better use HOL's datatype package;
   974 
   975 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   976 the old syntax may be recovered as follows:
   977 
   978   syntax (symbols)
   979     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   980       (infixl "\\<oplus>" 100)
   981 
   982 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   983 
   984 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   985 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   986 internally;
   987 
   988 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   989 changed from A/r to A//r;
   990 
   991 * ZF: new treatment of arithmetic (nat & int) may break some old
   992 proofs;
   993 
   994 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   995 rulify -> rule_format, elimify -> elim_format, ...);
   996 
   997 * Isar/Provers: intro/elim/dest attributes changed; renamed
   998 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   999 should have to change intro!! to intro? only); replaced "delrule" by
  1000 "rule del";
  1001 
  1002 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1003 
  1004 * Provers: strengthened force_tac by using new first_best_tac;
  1005 
  1006 * LaTeX document preparation: several changes of isabelle.sty (see
  1007 lib/texinputs);
  1008 
  1009 
  1010 *** Document preparation ***
  1011 
  1012 * formal comments (text blocks etc.) in new-style theories may now
  1013 contain antiquotations of thm/prop/term/typ/text to be presented
  1014 according to latex print mode; concrete syntax is like this:
  1015 @{term[show_types] "f(x) = a + x"};
  1016 
  1017 * isatool mkdir provides easy setup of Isabelle session directories,
  1018 including proper document sources;
  1019 
  1020 * generated LaTeX sources are now deleted after successful run
  1021 (isatool document -c); may retain a copy somewhere else via -D option
  1022 of isatool usedir;
  1023 
  1024 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1025 style files, achieving self-contained LaTeX sources and simplifying
  1026 LaTeX debugging;
  1027 
  1028 * old-style theories now produce (crude) LaTeX output as well;
  1029 
  1030 * browser info session directories are now self-contained (may be put
  1031 on WWW server seperately); improved graphs of nested sessions; removed
  1032 graph for 'all sessions';
  1033 
  1034 * several improvements in isabelle style files; \isabellestyle{it}
  1035 produces fake math mode output; \isamarkupheader is now \section by
  1036 default; see lib/texinputs/isabelle.sty etc.;
  1037 
  1038 
  1039 *** Isar ***
  1040 
  1041 * Isar/Pure: local results and corresponding term bindings are now
  1042 subject to Hindley-Milner polymorphism (similar to ML); this
  1043 accommodates incremental type-inference very nicely;
  1044 
  1045 * Isar/Pure: new derived language element 'obtain' supports
  1046 generalized existence reasoning;
  1047 
  1048 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1049 support accumulation of results, without applying any rules yet;
  1050 useful to collect intermediate results without explicit name
  1051 references, and for use with transitivity rules with more than 2
  1052 premises;
  1053 
  1054 * Isar/Pure: scalable support for case-analysis type proofs: new
  1055 'case' language element refers to local contexts symbolically, as
  1056 produced by certain proof methods; internally, case names are attached
  1057 to theorems as "tags";
  1058 
  1059 * Isar/Pure: theory command 'hide' removes declarations from
  1060 class/type/const name spaces;
  1061 
  1062 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1063 indicate potential overloading;
  1064 
  1065 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1066 
  1067 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1068 "{a,b,c}" instead of {a,b,c};
  1069 
  1070 * Isar/Pure now provides its own version of intro/elim/dest
  1071 attributes; useful for building new logics, but beware of confusion
  1072 with the version in Provers/classical;
  1073 
  1074 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1075 case name 'antecedent';
  1076 
  1077 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1078 to the current context is now done automatically);
  1079 
  1080 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1081 for definining proof methods in ML;
  1082 
  1083 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1084 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1085 most cases, one should have to change intro!! to intro? only);
  1086 replaced "delrule" by "rule del";
  1087 
  1088 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1089 'symmetric' attribute (the latter supercedes [RS sym]);
  1090 
  1091 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1092 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1093 well (including splits);
  1094 
  1095 * Isar/Provers: Simplifier and Classical methods now support all kind
  1096 of modifiers used in the past, including 'cong', 'iff', etc.
  1097 
  1098 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1099 of Simplifier and Classical reasoner);
  1100 
  1101 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1102 now support named cases; major packages (inductive, datatype, primrec,
  1103 recdef) support case names and properly name parameters;
  1104 
  1105 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1106 monotonicity conditions are extracted to be proven at end of
  1107 calculations;
  1108 
  1109 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1110 method anyway;
  1111 
  1112 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1113 split_if split_if_asm; datatype package provides theorems foo.splits =
  1114 foo.split foo.split_asm for each datatype;
  1115 
  1116 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1117 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1118 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1119 use "(cases (simplified))" method in proper proof texts);
  1120 
  1121 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1122 
  1123 * Isar: names of theorems etc. may be natural numbers as well;
  1124 
  1125 * Isar: 'pr' command: optional arguments for goals_limit and
  1126 ProofContext.prems_limit; no longer prints theory contexts, but only
  1127 proof states;
  1128 
  1129 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1130 additional print modes to be specified; e.g. "pr(latex)" will print
  1131 proof state according to the Isabelle LaTeX style;
  1132 
  1133 * Isar: improved support for emulating tactic scripts, including proof
  1134 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1135 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1136 (for HOL datatypes);
  1137 
  1138 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1139 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1140 'proof method scripts' have to be in depth-first order;
  1141 
  1142 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1143 
  1144 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1145 should instead use individual commands for printing items
  1146 (print_commands, print_methods etc.);
  1147 
  1148 * Isar: added 'nothing' --- the empty list of theorems;
  1149 
  1150 
  1151 *** HOL ***
  1152 
  1153 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1154 corresponding virtual machine and a specification of its bytecode
  1155 verifier and a lightweight bytecode verifier, including proofs of
  1156 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1157 Cornelia Pusch (see also the homepage of project Bali at
  1158 http://isabelle.in.tum.de/Bali/);
  1159 
  1160 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1161 Clemens Ballarin;
  1162 
  1163 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1164 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1165 Rasmussen;
  1166 
  1167 * HOL/Lattice: fundamental concepts of lattice theory and order
  1168 structures, including duals, properties of bounds versus algebraic
  1169 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1170 Theorem for complete lattices etc.; may also serve as a demonstration
  1171 for abstract algebraic reasoning using axiomatic type classes, and
  1172 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1173 
  1174 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1175 von Oheimb;
  1176 
  1177 * HOL/IMPP: extension of IMP with local variables and mutually
  1178 recursive procedures, by David von Oheimb;
  1179 
  1180 * HOL/Lambda: converted into new-style theory and document;
  1181 
  1182 * HOL/ex/Multiquote: example of multiple nested quotations and
  1183 anti-quotations -- basically a generalized version of de-Bruijn
  1184 representation; very useful in avoiding lifting of operations;
  1185 
  1186 * HOL/record: added general record equality rule to simpset; fixed
  1187 select-update simplification procedure to handle extended records as
  1188 well; admit "r" as field name;
  1189 
  1190 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1191 other numeric types and also as the identity of groups, rings, etc.;
  1192 
  1193 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1194 Types nat and int belong to this axclass;
  1195 
  1196 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1197    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1198    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1199   two terms #m*u and #n*u are replaced by #(m+n)*u
  1200     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1201   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1202     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1203 
  1204 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1205 powerful prover for predicate logic but knows nothing of clasets; see
  1206 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1207 
  1208 * HOL: new version of "case_tac" subsumes both boolean case split and
  1209 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1210 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1211 
  1212 * HOL: simplification no longer dives into case-expressions: only the
  1213 selector expression is simplified, but not the remaining arms; to
  1214 enable full simplification of case-expressions for datatype t, you may
  1215 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1216 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1217 
  1218 * HOL/recdef: the recursion equations generated by 'recdef' for
  1219 function 'f' are now called f.simps instead of f.rules; if all
  1220 termination conditions are proved automatically, these simplification
  1221 rules are added to the simpset, as in primrec; rules may be named
  1222 individually as well, resulting in a separate list of theorems for
  1223 each equation;
  1224 
  1225 * HOL/While is a new theory that provides a while-combinator. It
  1226 permits the definition of tail-recursive functions without the
  1227 provision of a termination measure. The latter is necessary once the
  1228 invariant proof rule for while is applied.
  1229 
  1230 * HOL: new (overloaded) notation for the set of elements below/above
  1231 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1232 
  1233 * HOL: theorems impI, allI, ballI bound as "strip";
  1234 
  1235 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1236 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1237 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1238 
  1239 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1240 
  1241 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1242 main HOL, but was unused);
  1243 
  1244 * HOL: fewer consts declared as global (e.g. have to refer to
  1245 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1246 
  1247 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1248 in case of overlap with user translations (e.g. judgements over
  1249 tuples); (note that the underlying logical represenation is still
  1250 bogus);
  1251 
  1252 
  1253 *** ZF ***
  1254 
  1255 * ZF: simplification automatically cancels common terms in arithmetic
  1256 expressions over nat and int;
  1257 
  1258 * ZF: new treatment of nat to minimize type-checking: all operators
  1259 coerce their operands to a natural number using the function natify,
  1260 making the algebraic laws unconditional;
  1261 
  1262 * ZF: as above, for int: operators coerce their operands to an integer
  1263 using the function intify;
  1264 
  1265 * ZF: the integer library now contains many of the usual laws for the
  1266 orderings, including $<=, and monotonicity laws for $+ and $*;
  1267 
  1268 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1269 simplification;
  1270 
  1271 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1272 to the simplifier and classical reasoner simultaneously;
  1273 
  1274 
  1275 *** General ***
  1276 
  1277 * Provers: blast_tac now handles actual object-logic rules as
  1278 assumptions; note that auto_tac uses blast_tac internally as well;
  1279 
  1280 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1281 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1282 
  1283 * Provers: delrules now handles destruct rules as well (no longer need
  1284 explicit make_elim);
  1285 
  1286 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1287   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1288 use instead the strong form,
  1289   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1290 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1291 from destruct-rules;
  1292 
  1293 * Provers: Simplifier.easy_setup provides a fast path to basic
  1294 Simplifier setup for new object-logics;
  1295 
  1296 * Pure: AST translation rules no longer require constant head on LHS;
  1297 
  1298 * Pure: improved name spaces: ambiguous output is qualified; support
  1299 for hiding of names;
  1300 
  1301 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1302 XSYMBOL_HOME; no longer need to do manual configuration in most
  1303 situations;
  1304 
  1305 * system: compression of ML heaps images may now be controlled via -c
  1306 option of isabelle and isatool usedir (currently only observed by
  1307 Poly/ML);
  1308 
  1309 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1310 useful for remote X11);
  1311 
  1312 * system: provide TAGS file for Isabelle sources;
  1313 
  1314 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1315 order;
  1316 
  1317 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1318 timing flag supersedes proof_timing and Toplevel.trace;
  1319 
  1320 * ML: new combinators |>> and |>>> for incremental transformations
  1321 with secondary results (e.g. certain theory extensions):
  1322 
  1323 * ML: PureThy.add_defs gets additional argument to indicate potential
  1324 overloading (usually false);
  1325 
  1326 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1327 results;
  1328 
  1329 
  1330 
  1331 New in Isabelle99 (October 1999)
  1332 --------------------------------
  1333 
  1334 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1335 
  1336 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1337 are no longer simplified.  (This allows the simplifier to unfold recursive
  1338 functional programs.)  To restore the old behaviour, declare
  1339 
  1340     Delcongs [if_weak_cong];
  1341 
  1342 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1343 complement;
  1344 
  1345 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1346 
  1347 * HOL/datatype: mutual_induct_tac no longer exists --
  1348   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1349 
  1350 * HOL/typedef: fixed type inference for representing set; type
  1351 arguments now have to occur explicitly on the rhs as type constraints;
  1352 
  1353 * ZF: The con_defs part of an inductive definition may no longer refer
  1354 to constants declared in the same theory;
  1355 
  1356 * HOL, ZF: the function mk_cases, generated by the inductive
  1357 definition package, has lost an argument.  To simplify its result, it
  1358 uses the default simpset instead of a supplied list of theorems.
  1359 
  1360 * HOL/List: the constructors of type list are now Nil and Cons;
  1361 
  1362 * Simplifier: the type of the infix ML functions
  1363         setSSolver addSSolver setSolver addSolver
  1364 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1365 for packaging solvers. A solver is created via
  1366         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1367 where the string argument is only a comment.
  1368 
  1369 
  1370 *** Proof tools ***
  1371 
  1372 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1373 decision procedure for linear arithmetic. Currently it is used for
  1374 types `nat', `int', and `real' in HOL (see below); it can, should and
  1375 will be instantiated for other types and logics as well.
  1376 
  1377 * The simplifier now accepts rewrite rules with flexible heads, eg
  1378      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1379   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1380   matching.
  1381 
  1382 
  1383 *** General ***
  1384 
  1385 * New Isabelle/Isar subsystem provides an alternative to traditional
  1386 tactical theorem proving; together with the ProofGeneral/isar user
  1387 interface it offers an interactive environment for developing human
  1388 readable proof documents (Isar == Intelligible semi-automated
  1389 reasoning); for further information see isatool doc isar-ref,
  1390 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1391 
  1392 * improved and simplified presentation of theories: better HTML markup
  1393 (including colors), graph views in several sizes; isatool usedir now
  1394 provides a proper interface for user theories (via -P option); actual
  1395 document preparation based on (PDF)LaTeX is available as well (for
  1396 new-style theories only); see isatool doc system for more information;
  1397 
  1398 * native support for Proof General, both for classic Isabelle and
  1399 Isabelle/Isar;
  1400 
  1401 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1402 using the graph browser tool;
  1403 
  1404 * Isabelle manuals now also available as PDF;
  1405 
  1406 * theory loader rewritten from scratch (may not be fully
  1407 bug-compatible); old loadpath variable has been replaced by show_path,
  1408 add_path, del_path, reset_path functions; new operations such as
  1409 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1410 isatool doc ref);
  1411 
  1412 * improved isatool install: option -k creates KDE application icon,
  1413 option -p DIR installs standalone binaries;
  1414 
  1415 * added ML_PLATFORM setting (useful for cross-platform installations);
  1416 more robust handling of platform specific ML images for SML/NJ;
  1417 
  1418 * the settings environment is now statically scoped, i.e. it is never
  1419 created again in sub-processes invoked from isabelle, isatool, or
  1420 Isabelle;
  1421 
  1422 * path element specification '~~' refers to '$ISABELLE_HOME';
  1423 
  1424 * in locales, the "assumes" and "defines" parts may be omitted if
  1425 empty;
  1426 
  1427 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1428 long arrows);
  1429 
  1430 * new print_mode "HTML";
  1431 
  1432 * new flag show_tags controls display of tags of theorems (which are
  1433 basically just comments that may be attached by some tools);
  1434 
  1435 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1436 mode and goal output format:
  1437 
  1438 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1439 244c244
  1440 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1441 ---
  1442 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1443 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1444 181c181
  1445 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1446 ---
  1447 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1448 
  1449 * function bind_thms stores lists of theorems (cf. bind_thm);
  1450 
  1451 * new shorthand tactics ftac, eatac, datac, fatac;
  1452 
  1453 * qed (and friends) now accept "" as result name; in that case the
  1454 theorem is not stored, but proper checks and presentation of the
  1455 result still apply;
  1456 
  1457 * theorem database now also indexes constants "Trueprop", "all",
  1458 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1459 
  1460 
  1461 *** HOL ***
  1462 
  1463 ** HOL arithmetic **
  1464 
  1465 * There are now decision procedures for linear arithmetic over nat and
  1466 int:
  1467 
  1468 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1469 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1470 are treated as atomic; subformulae not involving type `nat' or `int'
  1471 are ignored; quantified subformulae are ignored unless they are
  1472 positive universal or negative existential. The tactic has to be
  1473 invoked by hand and can be a little bit slow. In particular, the
  1474 running time is exponential in the number of occurrences of `min' and
  1475 `max', and `-' on `nat'.
  1476 
  1477 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1478 (negated) (in)equalities among the premises and the conclusion into
  1479 account (i.e. no compound formulae) and does not know about `min' and
  1480 `max', and `-' on `nat'. It is fast and is used automatically by the
  1481 simplifier.
  1482 
  1483 NB: At the moment, these decision procedures do not cope with mixed
  1484 nat/int formulae where the two parts interact, such as `m < n ==>
  1485 int(m) < int(n)'.
  1486 
  1487 * HOL/Numeral provides a generic theory of numerals (encoded
  1488 efficiently as bit strings); setup for types nat/int/real is in place;
  1489 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1490 int, existing theories and proof scripts may require a few additional
  1491 type constraints;
  1492 
  1493 * integer division and remainder can now be performed on constant
  1494 arguments;
  1495 
  1496 * many properties of integer multiplication, division and remainder
  1497 are now available;
  1498 
  1499 * An interface to the Stanford Validity Checker (SVC) is available through the
  1500 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1501 are proved automatically.  SVC must be installed separately, and its results
  1502 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1503 invocation of the underlying oracle).  For SVC see
  1504   http://verify.stanford.edu/SVC
  1505 
  1506 * IsaMakefile: the HOL-Real target now builds an actual image;
  1507 
  1508 
  1509 ** HOL misc **
  1510 
  1511 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1512 (in Isabelle/Isar) -- by Gertrud Bauer;
  1513 
  1514 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1515 analysis for assembly languages with subtypes;
  1516 
  1517 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1518 -- avoids syntactic ambiguities and treats state, transition, and
  1519 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1520 changed syntax and (many) tactics;
  1521 
  1522 * HOL/inductive: Now also handles more general introduction rules such
  1523   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1524   theorems are now maintained within the theory (maintained via the
  1525   "mono" attribute);
  1526 
  1527 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1528   (using function types) such as
  1529 
  1530   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1531 
  1532 * HOL/record: record_simproc (part of the default simpset) takes care
  1533 of selectors applied to updated records; record_split_tac is no longer
  1534 part of the default claset; update_defs may now be removed from the
  1535 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1536 
  1537   claset_ref () := claset() addSWrapper record_split_wrapper;
  1538   Delsimprocs [record_simproc]
  1539 
  1540 * HOL/typedef: fixed type inference for representing set; type
  1541 arguments now have to occur explicitly on the rhs as type constraints;
  1542 
  1543 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1544 names rather than an ML expression;
  1545 
  1546 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1547 supplied later.  Program schemes can be defined, such as
  1548     "While B C s = (if B s then While B C (C s) else s)"
  1549 where the well-founded relation can be chosen after B and C have been given.
  1550 
  1551 * HOL/List: the constructors of type list are now Nil and Cons;
  1552 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1553 course, ML tools referring to List.list.op # etc. have to be adapted;
  1554 
  1555 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1556 disabled by default; run isabelle with option -m HOL to get back to
  1557 the original Gordon/HOL-style output;
  1558 
  1559 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1560 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1561 
  1562 * HOL basic syntax simplified (more orthogonal): all variants of
  1563 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1564 Eps operator is provided as well: "SOME x. P[x]";
  1565 
  1566 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1567 
  1568 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1569 thus available for user theories;
  1570 
  1571 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1572 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1573 time;
  1574 
  1575 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1576 several times and then mp;
  1577 
  1578 
  1579 *** LK ***
  1580 
  1581 * the notation <<...>> is now available as a notation for sequences of
  1582 formulas;
  1583 
  1584 * the simplifier is now installed
  1585 
  1586 * the axiom system has been generalized (thanks to Soren Heilmann)
  1587 
  1588 * the classical reasoner now has a default rule database
  1589 
  1590 
  1591 *** ZF ***
  1592 
  1593 * new primrec section allows primitive recursive functions to be given
  1594 directly (as in HOL) over datatypes and the natural numbers;
  1595 
  1596 * new tactics induct_tac and exhaust_tac for induction (or case
  1597 analysis) over datatypes and the natural numbers;
  1598 
  1599 * the datatype declaration of type T now defines the recursor T_rec;
  1600 
  1601 * simplification automatically does freeness reasoning for datatype
  1602 constructors;
  1603 
  1604 * automatic type-inference, with AddTCs command to insert new
  1605 type-checking rules;
  1606 
  1607 * datatype introduction rules are now added as Safe Introduction rules
  1608 to the claset;
  1609 
  1610 * the syntax "if P then x else y" is now available in addition to
  1611 if(P,x,y);
  1612 
  1613 
  1614 *** Internal programming interfaces ***
  1615 
  1616 * tuned simplifier trace output; new flag debug_simp;
  1617 
  1618 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1619 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1620 
  1621 * AxClass.axclass_tac lost the theory argument;
  1622 
  1623 * tuned current_goals_markers semantics: begin / end goal avoids
  1624 printing empty lines;
  1625 
  1626 * removed prs and prs_fn hook, which was broken because it did not
  1627 include \n in its semantics, forcing writeln to add one
  1628 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1629 string -> unit if you really want to output text without newline;
  1630 
  1631 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1632 plain output, interface builders may have to enable 'isabelle_font'
  1633 mode to get Isabelle font glyphs as before;
  1634 
  1635 * refined token_translation interface; INCOMPATIBILITY: output length
  1636 now of type real instead of int;
  1637 
  1638 * theory loader actions may be traced via new ThyInfo.add_hook
  1639 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1640 your own database of information attached to *whole* theories -- as
  1641 opposed to intra-theory data slots offered via TheoryDataFun;
  1642 
  1643 * proper handling of dangling sort hypotheses (at last!);
  1644 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1645 extra sort hypotheses that can be witnessed from the type signature;
  1646 the force_strip_shyps flag is gone, any remaining shyps are simply
  1647 left in the theorem (with a warning issued by strip_shyps_warning);
  1648 
  1649 
  1650 
  1651 New in Isabelle98-1 (October 1998)
  1652 ----------------------------------
  1653 
  1654 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1655 
  1656 * several changes of automated proof tools;
  1657 
  1658 * HOL: major changes to the inductive and datatype packages, including
  1659 some minor incompatibilities of theory syntax;
  1660 
  1661 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1662 called `inj_on';
  1663 
  1664 * HOL: removed duplicate thms in Arith:
  1665   less_imp_add_less  should be replaced by  trans_less_add1
  1666   le_imp_add_le      should be replaced by  trans_le_add1
  1667 
  1668 * HOL: unary minus is now overloaded (new type constraints may be
  1669 required);
  1670 
  1671 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1672 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1673 now taken as an integer constant.
  1674 
  1675 * Pure: ML function 'theory_of' renamed to 'theory';
  1676 
  1677 
  1678 *** Proof tools ***
  1679 
  1680 * Simplifier:
  1681   1. Asm_full_simp_tac is now more aggressive.
  1682      1. It will sometimes reorient premises if that increases their power to
  1683         simplify.
  1684      2. It does no longer proceed strictly from left to right but may also
  1685         rotate premises to achieve further simplification.
  1686      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1687      old Asm_full_simp_tac in that it does not rotate premises.
  1688   2. The simplifier now knows a little bit about nat-arithmetic.
  1689 
  1690 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1691 allows for selected deletion of wrappers, by introduction of names for
  1692 wrapper functionals.  This implies that addbefore, addSbefore,
  1693 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1694 and that adding two tactics with the same name overwrites the first
  1695 one (emitting a warning).
  1696   type wrapper = (int -> tactic) -> (int -> tactic)
  1697   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1698   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1699   delWrapper, delSWrapper: claset *  string            -> claset
  1700   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1701 
  1702 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1703 semantics; addbefore now affects only the unsafe part of step_tac
  1704 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1705 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1706 by Force_tac;
  1707 
  1708 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1709 compWrapper; added safe wrapper (and access functions for it);
  1710 
  1711 * HOL/split_all_tac is now much faster and fails if there is nothing
  1712 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1713 and the names of the automatically generated variables have changed.
  1714 split_all_tac has moved within claset() from unsafe wrappers to safe
  1715 wrappers, which means that !!-bound variables are split much more
  1716 aggressively, and safe_tac and clarify_tac now split such variables.
  1717 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1718 Note: the same holds for record_split_tac, which does the job of
  1719 split_all_tac for record fields.
  1720 
  1721 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1722 permanently to the default simpset using Addsplits just like
  1723 Addsimps. They can be removed via Delsplits just like
  1724 Delsimps. Lower-case versions are also available.
  1725 
  1726 * HOL/Simplifier: The rule split_if is now part of the default
  1727 simpset. This means that the simplifier will eliminate all occurrences
  1728 of if-then-else in the conclusion of a goal. To prevent this, you can
  1729 either remove split_if completely from the default simpset by
  1730 `Delsplits [split_if]' or remove it in a specific call of the
  1731 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1732 other case splitting rules to/from the default simpset: every datatype
  1733 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1734 t is the name of the datatype).
  1735 
  1736 * Classical reasoner / Simplifier combination: new force_tac (and
  1737 derivatives Force_tac, force) combines rewriting and classical
  1738 reasoning (and whatever other tools) similarly to auto_tac, but is
  1739 aimed to solve the given subgoal completely.
  1740 
  1741 
  1742 *** General ***
  1743 
  1744 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1745 and `goalw': the theory is no longer needed as an explicit argument -
  1746 the current theory context is used; assumptions are no longer returned
  1747 at the ML-level unless one of them starts with ==> or !!; it is
  1748 recommended to convert to these new commands using isatool fixgoal
  1749 (backup your sources first!);
  1750 
  1751 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1752 the current theory context, and 'theory' to lookup stored theories;
  1753 
  1754 * new theory section 'locale' for declaring constants, assumptions and
  1755 definitions that have local scope;
  1756 
  1757 * new theory section 'nonterminals' for purely syntactic types;
  1758 
  1759 * new theory section 'setup' for generic ML setup functions
  1760 (e.g. package initialization);
  1761 
  1762 * the distribution now includes Isabelle icons: see
  1763 lib/logo/isabelle-{small,tiny}.xpm;
  1764 
  1765 * isatool install - install binaries with absolute references to
  1766 ISABELLE_HOME/bin;
  1767 
  1768 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1769 
  1770 * print mode 'emacs' reserved for Isamode;
  1771 
  1772 * support multiple print (ast) translations per constant name;
  1773 
  1774 * theorems involving oracles are now printed with a suffixed [!];
  1775 
  1776 
  1777 *** HOL ***
  1778 
  1779 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1780 
  1781 * HOL/inductive package reorganized and improved: now supports mutual
  1782 definitions such as
  1783 
  1784   inductive EVEN ODD
  1785     intrs
  1786       null "0 : EVEN"
  1787       oddI "n : EVEN ==> Suc n : ODD"
  1788       evenI "n : ODD ==> Suc n : EVEN"
  1789 
  1790 new theorem list "elims" contains an elimination rule for each of the
  1791 recursive sets; inductive definitions now handle disjunctive premises
  1792 correctly (also ZF);
  1793 
  1794 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1795 "mutual_induct" no longer exists - the induction rule is always
  1796 contained in "induct";
  1797 
  1798 
  1799 * HOL/datatype package re-implemented and greatly improved: now
  1800 supports mutually recursive datatypes such as
  1801 
  1802   datatype
  1803     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1804             | SUM ('a aexp) ('a aexp)
  1805             | DIFF ('a aexp) ('a aexp)
  1806             | NUM 'a
  1807   and
  1808     'a bexp = LESS ('a aexp) ('a aexp)
  1809             | AND ('a bexp) ('a bexp)
  1810             | OR ('a bexp) ('a bexp)
  1811 
  1812 as well as indirectly recursive datatypes such as
  1813 
  1814   datatype
  1815     ('a, 'b) term = Var 'a
  1816                   | App 'b ((('a, 'b) term) list)
  1817 
  1818 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1819 induction on mutually / indirectly recursive datatypes.
  1820 
  1821 Primrec equations are now stored in theory and can be accessed via
  1822 <function_name>.simps.
  1823 
  1824 INCOMPATIBILITIES:
  1825 
  1826   - Theories using datatypes must now have theory Datatype as an
  1827     ancestor.
  1828   - The specific <typename>.induct_tac no longer exists - use the
  1829     generic induct_tac instead.
  1830   - natE has been renamed to nat.exhaust - use exhaust_tac
  1831     instead of res_inst_tac ... natE. Note that the variable
  1832     names in nat.exhaust differ from the names in natE, this
  1833     may cause some "fragile" proofs to fail.
  1834   - The theorems split_<typename>_case and split_<typename>_case_asm
  1835     have been renamed to <typename>.split and <typename>.split_asm.
  1836   - Since default sorts of type variables are now handled correctly,
  1837     some datatype definitions may have to be annotated with explicit
  1838     sort constraints.
  1839   - Primrec definitions no longer require function name and type
  1840     of recursive argument.
  1841 
  1842 Consider using isatool fixdatatype to adapt your theories and proof
  1843 scripts to the new package (backup your sources first!).
  1844 
  1845 
  1846 * HOL/record package: considerably improved implementation; now
  1847 includes concrete syntax for record types, terms, updates; theorems
  1848 for surjective pairing and splitting !!-bound record variables; proof
  1849 support is as follows:
  1850 
  1851   1) standard conversions (selectors or updates applied to record
  1852 constructor terms) are part of the standard simpset;
  1853 
  1854   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1855 made part of standard simpset and claset via addIffs;
  1856 
  1857   3) a tactic for record field splitting (record_split_tac) is part of
  1858 the standard claset (addSWrapper);
  1859 
  1860 To get a better idea about these rules you may retrieve them via
  1861 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1862 the name of your record type.
  1863 
  1864 The split tactic 3) conceptually simplifies by the following rule:
  1865 
  1866   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1867 
  1868 Thus any record variable that is bound by meta-all will automatically
  1869 blow up into some record constructor term, consequently the
  1870 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1871 solve record problems automatically.
  1872 
  1873 
  1874 * reorganized the main HOL image: HOL/Integ and String loaded by
  1875 default; theory Main includes everything;
  1876 
  1877 * automatic simplification of integer sums and comparisons, using cancellation;
  1878 
  1879 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1880 
  1881 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1882 
  1883 * many new identities for unions, intersections, set difference, etc.;
  1884 
  1885 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1886 called split_if, split_split, split_sum_case and split_nat_case (to go
  1887 with add/delsplits);
  1888 
  1889 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1890 (?x::unit) = (); this is made part of the default simpset, which COULD
  1891 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1892 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1893 unit_abs_eta_conv is added in order to counter the effect of
  1894 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1895 %u.f();
  1896 
  1897 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1898 makes more sense);
  1899 
  1900 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1901   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1902   disjointness reasoning but breaking a few old proofs.
  1903 
  1904 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1905 to 'converse' from 'inverse' (for compatibility with ZF and some
  1906 literature);
  1907 
  1908 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1909 the well-founded relation;
  1910 
  1911 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1912     Compl A.  The "Compl" syntax remains available as input syntax for this
  1913     release ONLY.
  1914 
  1915 * HOL/Update: new theory of function updates:
  1916     f(a:=b) == %x. if x=a then b else f x
  1917 may also be iterated as in f(a:=b,c:=d,...);
  1918 
  1919 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1920 
  1921 * HOL/List:
  1922   - new function list_update written xs[i:=v] that updates the i-th
  1923     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1924   - new function `upt' written [i..j(] which generates the list
  1925     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1926     bound write [i..j], which is a shorthand for [i..j+1(].
  1927   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1928 
  1929 * HOL/Arith:
  1930   - removed 'pred' (predecessor) function;
  1931   - generalized some theorems about n-1;
  1932   - many new laws about "div" and "mod";
  1933   - new laws about greatest common divisors (see theory ex/Primes);
  1934 
  1935 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1936 instead of "inverse";
  1937 
  1938 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1939   of the multiset ordering;
  1940 
  1941 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1942   (not included by default);
  1943 
  1944 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1945 
  1946 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1947   programs, i.e. different program variables may have different types.
  1948 
  1949 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1950   [previously, this check worked only if the rewrite rule was unconditional]
  1951   Now rew can involve either definitions or equalities (either == or =).
  1952 
  1953 
  1954 *** ZF ***
  1955 
  1956 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1957   only the theorems proved on ZF.ML;
  1958 
  1959 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1960   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1961   disjointness reasoning but breaking a few old proofs.
  1962 
  1963 * ZF/Update: new theory of function updates
  1964     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1965   may also be iterated as in f(a:=b,c:=d,...);
  1966 
  1967 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1968 
  1969 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1970   [previously, this check worked only if the rewrite rule was unconditional]
  1971   Now rew can involve either definitions or equalities (either == or =).
  1972 
  1973 * case_tac provided for compatibility with HOL
  1974     (like the old excluded_middle_tac, but with subgoals swapped)
  1975 
  1976 
  1977 *** Internal programming interfaces ***
  1978 
  1979 * Pure: several new basic modules made available for general use, see
  1980 also src/Pure/README;
  1981 
  1982 * improved the theory data mechanism to support encapsulation (data
  1983 kind name replaced by private Object.kind, acting as authorization
  1984 key); new type-safe user interface via functor TheoryDataFun; generic
  1985 print_data function becomes basically useless;
  1986 
  1987 * removed global_names compatibility flag -- all theory declarations
  1988 are qualified by default;
  1989 
  1990 * module Pure/Syntax now offers quote / antiquote translation
  1991 functions (useful for Hoare logic etc. with implicit dependencies);
  1992 see HOL/ex/Antiquote for an example use;
  1993 
  1994 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1995 cterm -> thm;
  1996 
  1997 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1998 subgoal;
  1999 
  2000 * Display.print_goals function moved to Locale.print_goals;
  2001 
  2002 * standard print function for goals supports current_goals_markers
  2003 variable for marking begin of proof, end of proof, start of goal; the
  2004 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2005 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2006 for example;
  2007 
  2008 
  2009 
  2010 New in Isabelle98 (January 1998)
  2011 --------------------------------
  2012 
  2013 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2014 
  2015 * changed lexical syntax of terms / types: dots made part of long
  2016 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2017 
  2018 * simpset (and claset) reference variable replaced by functions
  2019 simpset / simpset_ref;
  2020 
  2021 * no longer supports theory aliases (via merge) and non-trivial
  2022 implicit merge of thms' signatures;
  2023 
  2024 * most internal names of constants changed due to qualified names;
  2025 
  2026 * changed Pure/Sequence interface (see Pure/seq.ML);
  2027 
  2028 
  2029 *** General Changes ***
  2030 
  2031 * hierachically structured name spaces (for consts, types, axms, thms
  2032 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2033 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2034 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2035 long_names for fully qualified output names; NOTE: ML programs
  2036 (special tactics, packages etc.) referring to internal names may have
  2037 to be adapted to cope with fully qualified names; in case of severe
  2038 backward campatibility problems try setting 'global_names' at compile
  2039 time to have enrything declared within a flat name space; one may also
  2040 fine tune name declarations in theories via the 'global' and 'local'
  2041 section;
  2042 
  2043 * reimplemented the implicit simpset and claset using the new anytype
  2044 data filed in signatures; references simpset:simpset ref etc. are
  2045 replaced by functions simpset:unit->simpset and
  2046 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2047 to patch your ML files accordingly;
  2048 
  2049 * HTML output now includes theory graph data for display with Java
  2050 applet or isatool browser; data generated automatically via isatool
  2051 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2052 
  2053 * defs may now be conditional; improved rewrite_goals_tac to handle
  2054 conditional equations;
  2055 
  2056 * defs now admits additional type arguments, using TYPE('a) syntax;
  2057 
  2058 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2059 creates a new theory node; implicit merge of thms' signatures is
  2060 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2061 transfer:theory->thm->thm in (rare) cases;
  2062 
  2063 * improved handling of draft signatures / theories; draft thms (and
  2064 ctyps, cterms) are automatically promoted to real ones;
  2065 
  2066 * slightly changed interfaces for oracles: admit many per theory, named
  2067 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2068 
  2069 * print_goals: optional output of const types (set show_consts and
  2070 show_types);
  2071 
  2072 * improved output of warnings (###) and errors (***);
  2073 
  2074 * subgoal_tac displays a warning if the new subgoal has type variables;
  2075 
  2076 * removed old README and Makefiles;
  2077 
  2078 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2079 
  2080 * removed obsolete init_pps and init_database;
  2081 
  2082 * deleted the obsolete tactical STATE, which was declared by
  2083     fun STATE tacfun st = tacfun st st;
  2084 
  2085 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2086 (which abbreviates $HOME);
  2087 
  2088 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2089 use isatool fixseq to adapt your ML programs (this works for fully
  2090 qualified references to the Sequence structure only!);
  2091 
  2092 * use_thy no longer requires writable current directory; it always
  2093 reloads .ML *and* .thy file, if either one is out of date;
  2094 
  2095 
  2096 *** Classical Reasoner ***
  2097 
  2098 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2099 tactics that use classical reasoning to simplify a subgoal without
  2100 splitting it into several subgoals;
  2101 
  2102 * Safe_tac: like safe_tac but uses the default claset;
  2103 
  2104 
  2105 *** Simplifier ***
  2106 
  2107 * added simplification meta rules:
  2108     (asm_)(full_)simplify: simpset -> thm -> thm;
  2109 
  2110 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2111 logics (again);
  2112 
  2113 * added prems argument to simplification procedures;
  2114 
  2115 * HOL, FOL, ZF: added infix function `addsplits':
  2116   instead of `<simpset> setloop (split_tac <thms>)'
  2117   you can simply write `<simpset> addsplits <thms>'
  2118 
  2119 
  2120 *** Syntax ***
  2121 
  2122 * TYPE('a) syntax for type reflection terms;
  2123 
  2124 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2125 
  2126 * pretty printer: changed order of mixfix annotation preference (again!);
  2127 
  2128 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2129 
  2130 
  2131 *** HOL ***
  2132 
  2133 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2134   with `addloop' of the simplifier to faciliate case splitting in premises.
  2135 
  2136 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2137 
  2138 * HOL/Auth: new protocol proofs including some for the Internet
  2139   protocol TLS;
  2140 
  2141 * HOL/Map: new theory of `maps' a la VDM;
  2142 
  2143 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2144 cancelling out common nat summands from =, <, <= (in)equalities, or
  2145 differences; simplification procedures nat_cancel_factor for
  2146 cancelling common factor from =, <, <= (in)equalities over natural
  2147 sums; nat_cancel contains both kinds of procedures, it is installed by
  2148 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2149 
  2150 * HOL/simplifier: terms of the form
  2151   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2152   are rewritten to
  2153   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2154   and those of the form
  2155   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2156   are rewritten to
  2157   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2158 
  2159 * HOL/datatype
  2160   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2161 
  2162   P(t_case f1 ... fn x) =
  2163      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2164         ...
  2165        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2166      )
  2167 
  2168   and a theorem `split_t_case_asm' of the form
  2169 
  2170   P(t_case f1 ... fn x) =
  2171     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2172         ...
  2173        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2174      )
  2175   which can be added to a simpset via `addsplits'. The existing theorems
  2176   expand_list_case and expand_option_case have been renamed to
  2177   split_list_case and split_option_case.
  2178 
  2179 * HOL/Arithmetic:
  2180   - `pred n' is automatically converted to `n-1'.
  2181     Users are strongly encouraged not to use `pred' any longer,
  2182     because it will disappear altogether at some point.
  2183   - Users are strongly encouraged to write "0 < n" rather than
  2184     "n ~= 0". Theorems and proof tools have been modified towards this
  2185     `standard'.
  2186 
  2187 * HOL/Lists:
  2188   the function "set_of_list" has been renamed "set" (and its theorems too);
  2189   the function "nth" now takes its arguments in the reverse order and
  2190   has acquired the infix notation "!" as in "xs!n".
  2191 
  2192 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2193 
  2194 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2195   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2196 
  2197 * HOL/record: extensible records with schematic structural subtyping
  2198 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2199 still lacks various theorems and concrete record syntax;
  2200 
  2201 
  2202 *** HOLCF ***
  2203 
  2204 * removed "axioms" and "generated by" sections;
  2205 
  2206 * replaced "ops" section by extended "consts" section, which is capable of
  2207   handling the continuous function space "->" directly;
  2208 
  2209 * domain package:
  2210   . proves theorems immediately and stores them in the theory,
  2211   . creates hierachical name space,
  2212   . now uses normal mixfix annotations (instead of cinfix...),
  2213   . minor changes to some names and values (for consistency),
  2214   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2215   . separator between mutual domain defs: changed "," to "and",
  2216   . improved handling of sort constraints;  now they have to
  2217     appear on the left-hand side of the equations only;
  2218 
  2219 * fixed LAM <x,y,zs>.b syntax;
  2220 
  2221 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2222 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2223 
  2224 
  2225 *** FOL and ZF ***
  2226 
  2227 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2228   with `addloop' of the simplifier to faciliate case splitting in premises.
  2229 
  2230 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2231 in HOL, they strip ALL and --> from proved theorems;
  2232 
  2233 
  2234 
  2235 New in Isabelle94-8 (May 1997)
  2236 ------------------------------
  2237 
  2238 *** General Changes ***
  2239 
  2240 * new utilities to build / run / maintain Isabelle etc. (in parts
  2241 still somewhat experimental); old Makefiles etc. still functional;
  2242 
  2243 * new 'Isabelle System Manual';
  2244 
  2245 * INSTALL text, together with ./configure and ./build scripts;
  2246 
  2247 * reimplemented type inference for greater efficiency, better error
  2248 messages and clean internal interface;
  2249 
  2250 * prlim command for dealing with lots of subgoals (an easier way of
  2251 setting goals_limit);
  2252 
  2253 
  2254 *** Syntax ***
  2255 
  2256 * supports alternative (named) syntax tables (parser and pretty
  2257 printer); internal interface is provided by add_modesyntax(_i);
  2258 
  2259 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2260 be used in conjunction with the Isabelle symbol font; uses the
  2261 "symbols" syntax table;
  2262 
  2263 * added token_translation interface (may translate name tokens in
  2264 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2265 the current print_mode); IMPORTANT: user print translation functions
  2266 are responsible for marking newly introduced bounds
  2267 (Syntax.mark_boundT);
  2268 
  2269 * token translations for modes "xterm" and "xterm_color" that display
  2270 names in bold, underline etc. or colors (which requires a color
  2271 version of xterm);
  2272 
  2273 * infixes may now be declared with names independent of their syntax;
  2274 
  2275 * added typed_print_translation (like print_translation, but may
  2276 access type of constant);
  2277 
  2278 
  2279 *** Classical Reasoner ***
  2280 
  2281 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2282 some limitations.  Blast_tac...
  2283   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2284   + ignores elimination rules that don't have the correct format
  2285         (the conclusion MUST be a formula variable)
  2286   + ignores types, which can make HOL proofs fail
  2287   + rules must not require higher-order unification, e.g. apply_type in ZF
  2288     [message "Function Var's argument not a bound variable" relates to this]
  2289   + its proof strategy is more general but can actually be slower
  2290 
  2291 * substitution with equality assumptions no longer permutes other
  2292 assumptions;
  2293 
  2294 * minor changes in semantics of addafter (now called addaltern); renamed
  2295 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2296 (and access functions for it);
  2297 
  2298 * improved combination of classical reasoner and simplifier:
  2299   + functions for handling clasimpsets
  2300   + improvement of addss: now the simplifier is called _after_ the
  2301     safe steps.
  2302   + safe variant of addss called addSss: uses safe simplifications
  2303     _during_ the safe steps. It is more complete as it allows multiple
  2304     instantiations of unknowns (e.g. with slow_tac).
  2305 
  2306 *** Simplifier ***
  2307 
  2308 * added interface for simplification procedures (functions that
  2309 produce *proven* rewrite rules on the fly, depending on current
  2310 redex);
  2311 
  2312 * ordering on terms as parameter (used for ordered rewriting);
  2313 
  2314 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2315 
  2316 * the solver is now split into a safe and an unsafe part.
  2317 This should be invisible for the normal user, except that the
  2318 functions setsolver and addsolver have been renamed to setSolver and
  2319 addSolver; added safe_asm_full_simp_tac;
  2320 
  2321 
  2322 *** HOL ***
  2323 
  2324 * a generic induction tactic `induct_tac' which works for all datatypes and
  2325 also for type `nat';
  2326 
  2327 * a generic case distinction tactic `exhaust_tac' which works for all
  2328 datatypes and also for type `nat';
  2329 
  2330 * each datatype comes with a function `size';
  2331 
  2332 * patterns in case expressions allow tuple patterns as arguments to
  2333 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2334 
  2335 * primrec now also works with type nat;
  2336 
  2337 * recdef: a new declaration form, allows general recursive functions to be
  2338 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2339 
  2340 * the constant for negation has been renamed from "not" to "Not" to
  2341 harmonize with FOL, ZF, LK, etc.;
  2342 
  2343 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2344 infinite lists;
  2345 
  2346 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2347 
  2348 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2349 problems in commutative rings, using axiomatic type classes for + and *;
  2350 
  2351 * more examples in HOL/MiniML and HOL/Auth;
  2352 
  2353 * more default rewrite rules for quantifiers, union/intersection;
  2354 
  2355 * a new constant `arbitrary == @x.False';
  2356 
  2357 * HOLCF/IOA replaces old HOL/IOA;
  2358 
  2359 * HOLCF changes: derived all rules and arities
  2360   + axiomatic type classes instead of classes
  2361   + typedef instead of faking type definitions
  2362   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2363   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2364   + eliminated the types void, one, tr
  2365   + use unit lift and bool lift (with translations) instead of one and tr
  2366   + eliminated blift from Lift3.thy (use Def instead of blift)
  2367   all eliminated rules are derived as theorems --> no visible changes ;
  2368 
  2369 
  2370 *** ZF ***
  2371 
  2372 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2373 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2374 as ZF_cs addSIs [equalityI];
  2375 
  2376 
  2377 
  2378 New in Isabelle94-7 (November 96)
  2379 ---------------------------------
  2380 
  2381 * allowing negative levels (as offsets) in prlev and choplev;
  2382 
  2383 * super-linear speedup for large simplifications;
  2384 
  2385 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2386 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2387 FAIL); can suppress it using the command Delsimps (ex_simps @
  2388 all_simps); De Morgan laws are also now included, by default;
  2389 
  2390 * improved printing of ==>  :  ~:
  2391 
  2392 * new object-logic "Sequents" adds linear logic, while replacing LK
  2393 and Modal (thanks to Sara Kalvala);
  2394 
  2395 * HOL/Auth: correctness proofs for authentication protocols;
  2396 
  2397 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2398 examples on HOL/Auth);
  2399 
  2400 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2401 the rewriter and classical reasoner simultaneously;
  2402 
  2403 * function uresult no longer returns theorems in "standard" format;
  2404 regain previous version by: val uresult = standard o uresult;
  2405 
  2406 
  2407 
  2408 New in Isabelle94-6
  2409 -------------------
  2410 
  2411 * oracles -- these establish an interface between Isabelle and trusted
  2412 external reasoners, which may deliver results as theorems;
  2413 
  2414 * proof objects (in particular record all uses of oracles);
  2415 
  2416 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2417 
  2418 * "constdefs" section in theory files;
  2419 
  2420 * "primrec" section (HOL) no longer requires names;
  2421 
  2422 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2423 
  2424 
  2425 
  2426 New in Isabelle94-5
  2427 -------------------
  2428 
  2429 * reduced space requirements;
  2430 
  2431 * automatic HTML generation from theories;
  2432 
  2433 * theory files no longer require "..." (quotes) around most types;
  2434 
  2435 * new examples, including two proofs of the Church-Rosser theorem;
  2436 
  2437 * non-curried (1994) version of HOL is no longer distributed;
  2438 
  2439 
  2440 
  2441 New in Isabelle94-4
  2442 -------------------
  2443 
  2444 * greatly reduced space requirements;
  2445 
  2446 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2447 
  2448 * searchable theorem database (see the section "Retrieving theorems" on
  2449 page 8 of the Reference Manual);
  2450 
  2451 * new examples, including Grabczewski's monumental case study of the
  2452 Axiom of Choice;
  2453 
  2454 * The previous version of HOL renamed to Old_HOL;
  2455 
  2456 * The new version of HOL (previously called CHOL) uses a curried syntax
  2457 for functions.  Application looks like f a b instead of f(a,b);
  2458 
  2459 * Mutually recursive inductive definitions finally work in HOL;
  2460 
  2461 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2462 translates to the operator "split";
  2463 
  2464 
  2465 
  2466 New in Isabelle94-3
  2467 -------------------
  2468 
  2469 * new infix operator, addss, allowing the classical reasoner to
  2470 perform simplification at each step of its search.  Example:
  2471         fast_tac (cs addss ss)
  2472 
  2473 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2474 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2475 look like (a,b) instead of <a,b>;
  2476 
  2477 * PLEASE NOTE: CHOL will eventually replace HOL!
  2478 
  2479 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2480 It translates to the operator "split".  A new theory of integers is available;
  2481 
  2482 * In ZF, integer numerals now denote two's-complement binary integers.
  2483 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2484 
  2485 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2486 of the Axiom of Choice;
  2487 
  2488 
  2489 
  2490 New in Isabelle94-2
  2491 -------------------
  2492 
  2493 * Significantly faster resolution;
  2494 
  2495 * the different sections in a .thy file can now be mixed and repeated
  2496 freely;
  2497 
  2498 * Database of theorems for FOL, HOL and ZF.  New
  2499 commands including qed, qed_goal and bind_thm store theorems in the database.
  2500 
  2501 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2502 a given theory (thms_of), or find out what theory a theorem was proved in
  2503 (theory_of_thm);
  2504 
  2505 * Bugs fixed in the inductive definition and datatype packages;
  2506 
  2507 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2508 and HOL_dup_cs obsolete;
  2509 
  2510 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2511 have been removed;
  2512 
  2513 * Simpler definition of function space in ZF;
  2514 
  2515 * new results about cardinal and ordinal arithmetic in ZF;
  2516 
  2517 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2518 types;
  2519 
  2520 
  2521 $Id$