NEWS
author skalberg
Wed Mar 31 16:10:53 2004 +0200 (2004-03-31)
changeset 14503 255ad604e08e
parent 14480 14b7923b3307
child 14508 859b11514537
permissions -rw-r--r--
Added check that Theory.ML does not occur in the files section of the theory
Theory.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    10   Replaces linorder.ML.
    11 
    12 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    13   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    14   (\<a>...\<z>), are now considered normal letters, and can therefore
    15   be used anywhere where an ASCII letter (a...zA...Z) has until
    16   now. COMPATIBILITY: This obviously changes the parsing of some
    17   terms, especially where a symbol has been used as a binder, say
    18   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    19   as an identifier.  Fix it by inserting a space around former
    20   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    21   existing theory and ML files.
    22 
    23 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    24 
    25 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    26   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    27   a normal (but invisible) letter. For multiple letter subscripts repeat 
    28   \<^isub> like this: x\<^isub>1\<^isub>2. 
    29 
    30 * Pure: There are now sub-/superscripts that can span more than one
    31   character. Text between \<^bsub> and \<^esub> is set in subscript in
    32   PG and LaTeX, text between \<^bsup> and \<^esup> in superscript. The
    33   new control characters are not identifier parts.
    34 
    35 * Pure: Control-symbols of the form \<^raw...> will literally print the
    36   content of ... to the latex file instead of \isacntrl... . The ... 
    37   accepts all printable characters excluding the end bracket >.
    38 
    39 * Pure: Symbols may only start with one backslash: \<...>. \\<...> is no 
    40   longer accepted by the scanner.
    41 
    42 * Pure: Using new Isar command "finalconsts" (or the ML functions
    43   Theory.add_finals or Theory.add_finals_i) it is now possible to
    44   declare constants "final", which prevents their being given a definition
    45   later.  It is useful for constants whose behaviour is fixed axiomatically
    46   rather than definitionally, such as the meta-logic connectives.
    47 
    48 * Pure: It is now illegal to specify Theory.ML explicitly as a dependency
    49   in the files section of the theory Theory. (This is more of a diagnostic
    50   than a restriction, as the theory loader screws up if Theory.ML is manually
    51   loaded.)
    52 
    53 *** Isar ***
    54 
    55 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    56   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    57     locales are no longer forced to write Isar proof scripts.
    58     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    59     emulations.
    60   - INCOMPATIBILITY: names of variables to be instantiated may no
    61     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    62     This is consistent with the instantiation attribute "where".
    63 
    64 * Attributes "where" and "of":
    65   - Now take type variables of instantiated theorem into account when reading
    66     the instantiation string.  This fixes a bug that caused instantiated
    67     theorems to have too special types in some circumstances.
    68   - "where" permits explicit instantiations of type variables.
    69 
    70 * Calculation commands "moreover" and "also":
    71   Do not reset facts ("this") any more.
    72 
    73 * Locales:
    74   - Goal statements involving the context element "includes" no longer
    75     generate theorems with internal delta predicates (those ending on
    76     "_axioms") in the premise.
    77     Resolve particular premise with <locale>.intro to obtain old form.
    78   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    79     specification and "includes" elements in goal statement.
    80   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    81     [intro?] and [elim?] (respectively) by default.
    82 
    83 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    84   (Isar) contexts.
    85 
    86 *** HOL ***
    87 
    88 * Simplifier:
    89   - Much improved handling of linear and partial orders.
    90     Reasoners for linear and partial orders are set up for type classes
    91     "linorder" and "order" respectively, and are added to the default simpset
    92     as solvers.  This means that the simplifier can build transitivity chains
    93     to solve goals from the assumptions.
    94   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
    95     of blast or auto after simplification become unnecessary because the goal
    96     is solved by simplification already.
    97 
    98 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
    99     all proved in axiomatic type classes for semirings, rings and fields.
   100 
   101 * Numerics:
   102   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   103     now formalized using the Ring_and_Field theory mentioned above. 
   104   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   105     than before, because now they are set up once in a generic manner.
   106   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   107     Look for the general versions in Ring_and_Field (and Power if they concern
   108     exponentiation).
   109 
   110 * Type "rat" of the rational numbers is now available in HOL-Complex.
   111 
   112 * Records:
   113   - Record types are now by default printed with their type abbreviation
   114     instead of the list of all field types. This can be configured via
   115     the reference "print_record_type_abbr".
   116   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   117     (not enabled by default).
   118   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   119     EX x. x = sel r to True (not enabled by default).
   120   - Tactic "record_split_simp_tac" to split and simplify records added.
   121  
   122 * 'specification' command added, allowing for definition by
   123   specification.  There is also an 'ax_specification' command that
   124   introduces the new constants axiomatically.
   125 
   126 * arith(_tac) is now able to generate counterexamples for reals as well.
   127 
   128 * HOL-Algebra: new locale "ring" for non-commutative rings.
   129 
   130 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   131  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   132 
   133 * Unions and Intersections:
   134   The x-symbol output syntax of UN and INT has been changed
   135   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   136   i.e. the index formulae has become a subscript, like in normal math.
   137   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   138   The subscript version is also accepted as input syntax.
   139 
   140 * Unions and Intersections over Intervals:
   141   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   142   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   143   like in normal math, and corresponding versions for < and for intersection.
   144 
   145 * ML: the legacy theory structures Int and List have been removed. They had
   146   conflicted with ML Basis Library structures having the same names.
   147 
   148 * 'refute' command added to search for (finite) countermodels.  Only works
   149   for a fragment of HOL.  The installation of an external SAT solver is
   150   highly recommended.  See "HOL/Refute.thy" for details.
   151 
   152 
   153 New in Isabelle2003 (May 2003)
   154 --------------------------------
   155 
   156 *** General ***
   157 
   158 * Provers/simplifier:
   159 
   160   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   161     Assumptions are now subject to complete mutual simplification,
   162     not just from left to right. The simplifier now preserves
   163     the order of assumptions.
   164 
   165     Potential INCOMPATIBILITY:
   166 
   167     -- simp sometimes diverges where the old version did
   168        not, e.g. invoking simp on the goal
   169 
   170         [| P (f x); y = x; f x = f y |] ==> Q
   171 
   172        now gives rise to the infinite reduction sequence
   173 
   174         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   175 
   176        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   177        kind of problem.
   178 
   179     -- Tactics combining classical reasoner and simplification (such as auto)
   180        are also affected by this change, because many of them rely on
   181        simp. They may sometimes diverge as well or yield a different numbers
   182        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   183        in case of problems. Sometimes subsequent calls to the classical
   184        reasoner will fail because a preceeding call to the simplifier too
   185        eagerly simplified the goal, e.g. deleted redundant premises.
   186 
   187   - The simplifier trace now shows the names of the applied rewrite rules
   188 
   189   - You can limit the number of recursive invocations of the simplifier
   190     during conditional rewriting (where the simplifie tries to solve the
   191     conditions before applying the rewrite rule):
   192     ML "simp_depth_limit := n"
   193     where n is an integer. Thus you can force termination where previously
   194     the simplifier would diverge.
   195 
   196   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   197 
   198   - No longer aborts on failed congruence proof.  Instead, the
   199     congruence is ignored.
   200 
   201 * Pure: New generic framework for extracting programs from constructive
   202   proofs. See HOL/Extraction.thy for an example instantiation, as well
   203   as HOL/Extraction for some case studies.
   204 
   205 * Pure: The main goal of the proof state is no longer shown by default, only
   206 the subgoals. This behaviour is controlled by a new flag.
   207    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   208 (ML: Proof.show_main_goal).
   209 
   210 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   211 rules whose conclusion matches subgoal 1:
   212       PG menu: Isabelle/Isar -> Show me -> matching rules
   213 The rules are ordered by how closely they match the subgoal.
   214 In particular, rules that solve a subgoal outright are displayed first
   215 (or rather last, the way they are printed).
   216 (ML: ProofGeneral.print_intros())
   217 
   218 * Pure: New flag trace_unify_fail causes unification to print
   219 diagnostic information (PG: in trace buffer) when it fails. This is
   220 useful for figuring out why single step proofs like rule, erule or
   221 assumption failed.
   222 
   223 * Pure: Locale specifications now produce predicate definitions
   224 according to the body of text (covering assumptions modulo local
   225 definitions); predicate "loc_axioms" covers newly introduced text,
   226 while "loc" is cumulative wrt. all included locale expressions; the
   227 latter view is presented only on export into the global theory
   228 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   229 on the old view without predicates;
   230 
   231 * Pure: predefined locales "var" and "struct" are useful for sharing
   232 parameters (as in CASL, for example); just specify something like
   233 ``var x + var y + struct M'' as import;
   234 
   235 * Pure: improved thms_containing: proper indexing of facts instead of
   236 raw theorems; check validity of results wrt. current name space;
   237 include local facts of proof configuration (also covers active
   238 locales), cover fixed variables in index; may use "_" in term
   239 specification; an optional limit for the number of printed facts may
   240 be given (the default is 40);
   241 
   242 * Pure: disallow duplicate fact bindings within new-style theory files
   243 (batch-mode only);
   244 
   245 * Provers: improved induct method: assumptions introduced by case
   246 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   247 the goal statement); "foo" still refers to all facts collectively;
   248 
   249 * Provers: the function blast.overloaded has been removed: all constants
   250 are regarded as potentially overloaded, which improves robustness in exchange
   251 for slight decrease in efficiency;
   252 
   253 * Provers/linorder: New generic prover for transitivity reasoning over
   254 linear orders.  Note: this prover is not efficient!
   255 
   256 * Isar: preview of problems to finish 'show' now produce an error
   257 rather than just a warning (in interactive mode);
   258 
   259 
   260 *** HOL ***
   261 
   262 * arith(_tac)
   263 
   264  - Produces a counter example if it cannot prove a goal.
   265    Note that the counter example may be spurious if the goal is not a formula
   266    of quantifier-free linear arithmetic.
   267    In ProofGeneral the counter example appears in the trace buffer.
   268 
   269  - Knows about div k and mod k where k is a numeral of type nat or int.
   270 
   271  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   272    linear arithmetic fails. This takes account of quantifiers and divisibility.
   273    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   274 
   275 * simp's arithmetic capabilities have been enhanced a bit: it now
   276 takes ~= in premises into account (by performing a case split);
   277 
   278 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   279 are distributed over a sum of terms;
   280 
   281 * New tactic "trans_tac" and method "trans" instantiate
   282 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   283 "<=", "<" and "="). 
   284 
   285 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   286 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   287 
   288 * 'typedef' command has new option "open" to suppress the set
   289 definition;
   290 
   291 * functions Min and Max on finite sets have been introduced (theory
   292 Finite_Set);
   293 
   294 * attribute [symmetric] now works for relations as well; it turns
   295 (x,y) : R^-1 into (y,x) : R, and vice versa;
   296 
   297 * induct over a !!-quantified statement (say !!x1..xn):
   298   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   299 
   300 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   301 %x. None. Warning: empty_def now refers to the previously hidden definition
   302 of the empty set.
   303 
   304 * Algebra: formalization of classical algebra.  Intended as base for
   305 any algebraic development in Isabelle.  Currently covers group theory
   306 (up to Sylow's theorem) and ring theory (Universal Property of
   307 Univariate Polynomials).  Contributions welcome;
   308 
   309 * GroupTheory: deleted, since its material has been moved to Algebra;
   310 
   311 * Complex: new directory of the complex numbers with numeric constants, 
   312 nonstandard complex numbers, and some complex analysis, standard and 
   313 nonstandard (Jacques Fleuriot);
   314 
   315 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   316 
   317 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   318 Fleuriot);
   319 
   320 * Real/HahnBanach: updated and adapted to locales;
   321 
   322 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   323 Gray and Kramer);
   324 
   325 * UNITY: added the Meier-Sanders theory of progress sets;
   326 
   327 * MicroJava: bytecode verifier and lightweight bytecode verifier
   328 as abstract algorithms, instantiated to the JVM;
   329 
   330 * Bali: Java source language formalization. Type system, operational
   331 semantics, axiomatic semantics. Supported language features:
   332 classes, interfaces, objects,virtual methods, static methods,
   333 static/instance fields, arrays, access modifiers, definite
   334 assignment, exceptions.
   335 
   336 
   337 *** ZF ***
   338 
   339 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   340 universe, etc.);
   341 
   342 * Main ZF: virtually all theories converted to new-style format;
   343 
   344 
   345 *** ML ***
   346 
   347 * Pure: Tactic.prove provides sane interface for internal proofs;
   348 omits the infamous "standard" operation, so this is more appropriate
   349 than prove_goalw_cterm in many situations (e.g. in simprocs);
   350 
   351 * Pure: improved error reporting of simprocs;
   352 
   353 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   354 up simprocs;
   355 
   356 
   357 *** Document preparation ***
   358 
   359 * uses \par instead of \\ for line breaks in theory text. This may
   360 shift some page breaks in large documents. To get the old behaviour
   361 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   362 
   363 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   364 other packages
   365 
   366 * \<euro> now needs package babel/greek instead of marvosym (which
   367 broke \Rightarrow)
   368 
   369 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   370 textcomp package)
   371 
   372 
   373 New in Isabelle2002 (March 2002)
   374 --------------------------------
   375 
   376 *** Document preparation ***
   377 
   378 * greatly simplified document preparation setup, including more
   379 graceful interpretation of isatool usedir -i/-d/-D options, and more
   380 instructive isatool mkdir; users should basically be able to get
   381 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   382 users may run a separate document processing stage manually like this:
   383 "isatool usedir -D output HOL Test && isatool document Test/output";
   384 
   385 * theory dependency graph may now be incorporated into documents;
   386 isatool usedir -g true will produce session_graph.eps/.pdf for use
   387 with \includegraphics of LaTeX;
   388 
   389 * proper spacing of consecutive markup elements, especially text
   390 blocks after section headings;
   391 
   392 * support bold style (for single symbols only), input syntax is like
   393 this: "\<^bold>\<alpha>" or "\<^bold>A";
   394 
   395 * \<bullet> is now output as bold \cdot by default, which looks much
   396 better in printed text;
   397 
   398 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   399 note that these symbols are currently unavailable in Proof General /
   400 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   401 
   402 * isatool latex no longer depends on changed TEXINPUTS, instead
   403 isatool document copies the Isabelle style files to the target
   404 location;
   405 
   406 
   407 *** Isar ***
   408 
   409 * Pure/Provers: improved proof by cases and induction;
   410   - 'case' command admits impromptu naming of parameters (such as
   411     "case (Suc n)");
   412   - 'induct' method divinates rule instantiation from the inductive
   413     claim; no longer requires excessive ?P bindings for proper
   414     instantiation of cases;
   415   - 'induct' method properly enumerates all possibilities of set/type
   416     rules; as a consequence facts may be also passed through *type*
   417     rules without further ado;
   418   - 'induct' method now derives symbolic cases from the *rulified*
   419     rule (before it used to rulify cases stemming from the internal
   420     atomized version); this means that the context of a non-atomic
   421     statement becomes is included in the hypothesis, avoiding the
   422     slightly cumbersome show "PROP ?case" form;
   423   - 'induct' may now use elim-style induction rules without chaining
   424     facts, using ``missing'' premises from the goal state; this allows
   425     rules stemming from inductive sets to be applied in unstructured
   426     scripts, while still benefitting from proper handling of non-atomic
   427     statements; NB: major inductive premises need to be put first, all
   428     the rest of the goal is passed through the induction;
   429   - 'induct' proper support for mutual induction involving non-atomic
   430     rule statements (uses the new concept of simultaneous goals, see
   431     below);
   432   - append all possible rule selections, but only use the first
   433     success (no backtracking);
   434   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   435   - undeclared rule case names default to numbers 1, 2, 3, ...;
   436   - added 'print_induct_rules' (covered by help item in recent Proof
   437     General versions);
   438   - moved induct/cases attributes to Pure, methods to Provers;
   439   - generic method setup instantiated for FOL and HOL;
   440 
   441 * Pure: support multiple simultaneous goal statements, for example
   442 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   443 meta-level mechanism, this acts as if several individual goals had
   444 been stated separately; in particular common proof methods need to be
   445 repeated in order to cover all claims; note that a single elimination
   446 step is *not* sufficient to establish the two conjunctions, so this
   447 fails:
   448 
   449   assume "A & B" then have A and B ..   (*".." fails*)
   450 
   451 better use "obtain" in situations as above; alternative refer to
   452 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   453 
   454 * Pure: proper integration with ``locales''; unlike the original
   455 version by Florian Kammüller, Isar locales package high-level proof
   456 contexts rather than raw logical ones (e.g. we admit to include
   457 attributes everywhere); operations on locales include merge and
   458 rename; support for implicit arguments (``structures''); simultaneous
   459 type-inference over imports and text; see also HOL/ex/Locales.thy for
   460 some examples;
   461 
   462 * Pure: the following commands have been ``localized'', supporting a
   463 target locale specification "(in name)": 'lemma', 'theorem',
   464 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   465 stored both within the locale and at the theory level (exported and
   466 qualified by the locale name);
   467 
   468 * Pure: theory goals may now be specified in ``long'' form, with
   469 ad-hoc contexts consisting of arbitrary locale elements. for example
   470 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   471 definitions may be given, too); the result is a meta-level rule with
   472 the context elements being discharged in the obvious way;
   473 
   474 * Pure: new proof command 'using' allows to augment currently used
   475 facts after a goal statement ('using' is syntactically analogous to
   476 'apply', but acts on the goal's facts only); this allows chained facts
   477 to be separated into parts given before and after a claim, as in
   478 ``from a and b have C using d and e <proof>'';
   479 
   480 * Pure: renamed "antecedent" case to "rule_context";
   481 
   482 * Pure: new 'judgment' command records explicit information about the
   483 object-logic embedding (used by several tools internally); no longer
   484 use hard-wired "Trueprop";
   485 
   486 * Pure: added 'corollary' command;
   487 
   488 * Pure: fixed 'token_translation' command;
   489 
   490 * Pure: removed obsolete 'exported' attribute;
   491 
   492 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   493 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   494 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   495 
   496 * Pure: method 'atomize' presents local goal premises as object-level
   497 statements (atomic meta-level propositions); setup controlled via
   498 rewrite rules declarations of 'atomize' attribute; example
   499 application: 'induct' method with proper rule statements in improper
   500 proof *scripts*;
   501 
   502 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   503 now consider the syntactic context of assumptions, giving a better
   504 chance to get type-inference of the arguments right (this is
   505 especially important for locales);
   506 
   507 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   508 mode;
   509 
   510 * Pure/obtain: the formal conclusion "thesis", being marked as
   511 ``internal'', may no longer be reference directly in the text;
   512 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   513 situations;
   514 
   515 * Pure: generic 'sym' attribute which declares a rule both as pure
   516 'elim?' and for the 'symmetric' operation;
   517 
   518 * Pure: marginal comments ``--'' may now occur just anywhere in the
   519 text; the fixed correlation with particular command syntax has been
   520 discontinued;
   521 
   522 * Pure: new method 'rules' is particularly well-suited for proof
   523 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   524 but often produces more compact proof terms with less detours;
   525 
   526 * Pure/Provers/classical: simplified integration with pure rule
   527 attributes and methods; the classical "intro?/elim?/dest?"
   528 declarations coincide with the pure ones; the "rule" method no longer
   529 includes classically swapped intros; "intro" and "elim" methods no
   530 longer pick rules from the context; also got rid of ML declarations
   531 AddXIs/AddXEs/AddXDs; all of this has some potential for
   532 INCOMPATIBILITY;
   533 
   534 * Provers/classical: attribute 'swapped' produces classical inversions
   535 of introduction rules;
   536 
   537 * Provers/simplifier: 'simplified' attribute may refer to explicit
   538 rules instead of full simplifier context; 'iff' attribute handles
   539 conditional rules;
   540 
   541 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   542 
   543 * HOL: 'recdef' now fails on unfinished automated proofs, use
   544 "(permissive)" option to recover old behavior;
   545 
   546 * HOL: 'inductive' no longer features separate (collective) attributes
   547 for 'intros' (was found too confusing);
   548 
   549 * HOL: properly declared induction rules less_induct and
   550 wf_induct_rule;
   551 
   552 
   553 *** HOL ***
   554 
   555 * HOL: moved over to sane numeral syntax; the new policy is as
   556 follows:
   557 
   558   - 0 and 1 are polymorphic constants, which are defined on any
   559   numeric type (nat, int, real etc.);
   560 
   561   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   562   binary representation internally;
   563 
   564   - type nat has special constructor Suc, and generally prefers Suc 0
   565   over 1::nat and Suc (Suc 0) over 2::nat;
   566 
   567 This change may cause significant problems of INCOMPATIBILITY; here
   568 are some hints on converting existing sources:
   569 
   570   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   571   entities, so expressions involving "-" (unary or binary minus) need
   572   to be spaced properly;
   573 
   574   - existing occurrences of "1" may need to be constraint "1::nat" or
   575   even replaced by Suc 0; similar for old "2";
   576 
   577   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   578 
   579   - remove all special provisions on numerals in proofs;
   580 
   581 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   582 representation (depends on bin_arith_simps in the default context);
   583 
   584 * HOL: symbolic syntax for x^2 (numeral 2);
   585 
   586 * HOL: the class of all HOL types is now called "type" rather than
   587 "term"; INCOMPATIBILITY, need to adapt references to this type class
   588 in axclass/classes, instance/arities, and (usually rare) occurrences
   589 in typings (of consts etc.); internally the class is called
   590 "HOL.type", ML programs should refer to HOLogic.typeS;
   591 
   592 * HOL/record package improvements:
   593   - new derived operations "fields" to build a partial record section,
   594     "extend" to promote a fixed record to a record scheme, and
   595     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   596     declared as simp by default;
   597   - shared operations ("more", "fields", etc.) now need to be always
   598     qualified) --- potential INCOMPATIBILITY;
   599   - removed "make_scheme" operations (use "make" with "extend") --
   600     INCOMPATIBILITY;
   601   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   602   - provides cases/induct rules for use with corresponding Isar
   603     methods (for concrete records, record schemes, concrete more
   604     parts, and schematic more parts -- in that order);
   605   - internal definitions directly based on a light-weight abstract
   606     theory of product types over typedef rather than datatype;
   607 
   608 * HOL: generic code generator for generating executable ML code from
   609 specifications; specific support for HOL constructs such as inductive
   610 datatypes and sets, as well as recursive functions; can be invoked
   611 via 'generate_code' theory section;
   612 
   613 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   614 
   615 * HOL: consolidated and renamed several theories.  In particular:
   616 	Ord.thy has been absorbed into HOL.thy
   617 	String.thy has been absorbed into List.thy
   618  
   619 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   620 (beware of argument permutation!);
   621 
   622 * HOL: linorder_less_split superseded by linorder_cases;
   623 
   624 * HOL/List: "nodups" renamed to "distinct";
   625 
   626 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   627 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   628   - Ex_def has changed, now need to use some_eq_ex
   629 
   630 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   631 in this (rare) case use:
   632 
   633   delSWrapper "split_all_tac"
   634   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   635 
   636 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   637 MAY FAIL;
   638 
   639 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   640 Isabelle's type classes, ^ on functions and relations has too general
   641 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   642 necessary to attach explicit type constraints;
   643 
   644 * HOL/Relation: the prefix name of the infix "O" has been changed from
   645 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   646 renamed accordingly (eg "compI" -> "rel_compI").
   647 
   648 * HOL: syntax translations now work properly with numerals and records
   649 expressions;
   650 
   651 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   652 of "lam" -- INCOMPATIBILITY;
   653 
   654 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   655 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   656 renamed "Product_Type.unit";
   657 
   658 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   659 
   660 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   661 the "cases" method);
   662 
   663 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   664 Florian Kammüller);
   665 
   666 * HOL/IMP: updated and converted to new-style theory format; several
   667 parts turned into readable document, with proper Isar proof texts and
   668 some explanations (by Gerwin Klein);
   669 
   670 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   671 
   672 * HOL-Hyperreal is now a logic image;
   673 
   674 
   675 *** HOLCF ***
   676 
   677 * Isar: consts/constdefs supports mixfix syntax for continuous
   678 operations;
   679 
   680 * Isar: domain package adapted to new-style theory format, e.g. see
   681 HOLCF/ex/Dnat.thy;
   682 
   683 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   684 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   685 lift.induct_tac, always use UU instead of Undef;
   686 
   687 * HOLCF/IMP: updated and converted to new-style theory;
   688 
   689 
   690 *** ZF ***
   691 
   692 * Isar: proper integration of logic-specific tools and packages,
   693 including theory commands '(co)inductive', '(co)datatype',
   694 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   695 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   696 
   697 * theory Main no longer includes AC; for the Axiom of Choice, base
   698 your theory on Main_ZFC;
   699 
   700 * the integer library now covers quotients and remainders, with many
   701 laws relating division to addition, multiplication, etc.;
   702 
   703 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   704 typeless version of the formalism;
   705 
   706 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   707 format;
   708 
   709 * ZF/Induct: new directory for examples of inductive definitions,
   710 including theory Multiset for multiset orderings; converted to
   711 new-style theory format;
   712 
   713 * ZF: many new theorems about lists, ordinals, etc.;
   714 
   715 
   716 *** General ***
   717 
   718 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   719 variable proof controls level of detail: 0 = no proofs (only oracle
   720 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   721 also ref manual for further ML interfaces;
   722 
   723 * Pure/axclass: removed obsolete ML interface
   724 goal_subclass/goal_arity;
   725 
   726 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   727 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   728 separate tokens, so expressions involving minus need to be spaced
   729 properly;
   730 
   731 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   732 rather than "infixl" or "infixr";
   733 
   734 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   735 sort constraint specifications in type inference; e.g. "x::_::foo"
   736 ensures that the type of "x" is of sort "foo" (but not necessarily a
   737 type variable);
   738 
   739 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   740 control output of nested => (types); the default behavior is
   741 "type_brackets";
   742 
   743 * Pure/syntax: builtin parse translation for "_constify" turns valued
   744 tokens into AST constants;
   745 
   746 * Pure/syntax: prefer later declarations of translations and print
   747 translation functions; potential INCOMPATIBILITY: need to reverse
   748 multiple declarations for same syntax element constant;
   749 
   750 * Pure/show_hyps reset by default (in accordance to existing Isar
   751 practice);
   752 
   753 * Provers/classical: renamed addaltern to addafter, addSaltern to
   754 addSafter;
   755 
   756 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   757 as well;
   758 
   759 * system: tested support for MacOS X; should be able to get Isabelle +
   760 Proof General to work in a plain Terminal after installing Poly/ML
   761 (e.g. from the Isabelle distribution area) and GNU bash alone
   762 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   763 support requires further installations, e.g. from
   764 http://fink.sourceforge.net/);
   765 
   766 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   767 
   768 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   769 of 40 MB), cf. ML_OPTIONS;
   770 
   771 * system: Proof General keywords specification is now part of the
   772 Isabelle distribution (see etc/isar-keywords.el);
   773 
   774 * system: support for persistent Proof General sessions (refrain from
   775 outdating all loaded theories on startup); user may create writable
   776 logic images like this: ``isabelle -q HOL Test'';
   777 
   778 * system: smart selection of Isabelle process versus Isabelle
   779 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   780 run both "isabelle" and "Isabelle" even if file names are badly
   781 damaged (executable inspects the case of the first letter of its own
   782 name); added separate "isabelle-process" and "isabelle-interface";
   783 
   784 * system: refrain from any attempt at filtering input streams; no
   785 longer support ``8bit'' encoding of old isabelle font, instead proper
   786 iso-latin characters may now be used; the related isatools
   787 "symbolinput" and "nonascii" have disappeared as well;
   788 
   789 * system: removed old "xterm" interface (the print modes "xterm" and
   790 "xterm_color" are still available for direct use in a suitable
   791 terminal);
   792 
   793 
   794 
   795 New in Isabelle99-2 (February 2001)
   796 -----------------------------------
   797 
   798 *** Overview of INCOMPATIBILITIES ***
   799 
   800 * HOL: please note that theories in the Library and elsewhere often use the
   801 new-style (Isar) format; to refer to their theorems in an ML script you must
   802 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   803 
   804 * HOL: inductive package no longer splits induction rule aggressively,
   805 but only as far as specified by the introductions given; the old
   806 format may be recovered via ML function complete_split_rule or attribute
   807 'split_rule (complete)';
   808 
   809 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   810 gfp_Tarski to gfp_unfold;
   811 
   812 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   813 
   814 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   815 relation); infix "^^" has been renamed "``"; infix "``" has been
   816 renamed "`"; "univalent" has been renamed "single_valued";
   817 
   818 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   819 operation;
   820 
   821 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   822 
   823 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   824 
   825 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   826 consequence, it is no longer monotonic wrt. the local goal context
   827 (which is now passed through the inductive cases);
   828 
   829 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   830 \<gg> to \<ggreater>;
   831 
   832 
   833 *** Document preparation ***
   834 
   835 * \isabellestyle{NAME} selects version of Isabelle output (currently
   836 available: are "it" for near math-mode best-style output, "sl" for
   837 slanted text style, and "tt" for plain type-writer; if no
   838 \isabellestyle command is given, output is according to slanted
   839 type-writer);
   840 
   841 * support sub/super scripts (for single symbols only), input syntax is
   842 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   843 
   844 * some more standard symbols; see Appendix A of the system manual for
   845 the complete list of symbols defined in isabellesym.sty;
   846 
   847 * improved isabelle style files; more abstract symbol implementation
   848 (should now use \isamath{...} and \isatext{...} in custom symbol
   849 definitions);
   850 
   851 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   852 state; Note that presentation of goal states does not conform to
   853 actual human-readable proof documents.  Please do not include goal
   854 states into document output unless you really know what you are doing!
   855 
   856 * proper indentation of antiquoted output with proportional LaTeX
   857 fonts;
   858 
   859 * no_document ML operator temporarily disables LaTeX document
   860 generation;
   861 
   862 * isatool unsymbolize tunes sources for plain ASCII communication;
   863 
   864 
   865 *** Isar ***
   866 
   867 * Pure: Isar now suffers initial goal statements to contain unbound
   868 schematic variables (this does not conform to actual readable proof
   869 documents, due to unpredictable outcome and non-compositional proof
   870 checking); users who know what they are doing may use schematic goals
   871 for Prolog-style synthesis of proven results;
   872 
   873 * Pure: assumption method (an implicit finishing) now handles actual
   874 rules as well;
   875 
   876 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   877 initial goal, declare "that" only as Pure intro (only for single
   878 steps); the "that" rule assumption may now be involved in implicit
   879 finishing, thus ".." becomes a feasible for trivial obtains;
   880 
   881 * Pure: default proof step now includes 'intro_classes'; thus trivial
   882 instance proofs may be performed by "..";
   883 
   884 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   885 statements as well;
   886 
   887 * Pure: more robust selection of calculational rules;
   888 
   889 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   890 rule (as well as the assumption rule);
   891 
   892 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   893 lemmas, using the graph browser tool;
   894 
   895 * Pure: predict failure of "show" in interactive mode;
   896 
   897 * Pure: 'thms_containing' now takes actual terms as arguments;
   898 
   899 * HOL: improved method 'induct' --- now handles non-atomic goals
   900 (potential INCOMPATIBILITY); tuned error handling;
   901 
   902 * HOL: cases and induct rules now provide explicit hints about the
   903 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   904 any remaining facts are inserted into the goal verbatim;
   905 
   906 * HOL: local contexts (aka cases) may now contain term bindings as
   907 well; the 'cases' and 'induct' methods new provide a ?case binding for
   908 the result to be shown in each case;
   909 
   910 * HOL: added 'recdef_tc' command;
   911 
   912 * isatool convert assists in eliminating legacy ML scripts;
   913 
   914 
   915 *** HOL ***
   916 
   917 * HOL/Library: a collection of generic theories to be used together
   918 with main HOL; the theory loader path already includes this directory
   919 by default; the following existing theories have been moved here:
   920 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   921 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   922 
   923 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   924 modelling and verification task performed in Isabelle/HOL +
   925 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   926 
   927 * HOL/Algebra: special summation operator SUM no longer exists, it has
   928 been replaced by setsum; infix 'assoc' now has priority 50 (like
   929 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   930 'domain', this makes the theory consistent with mathematical
   931 literature;
   932 
   933 * HOL basics: added overloaded operations "inverse" and "divide"
   934 (infix "/"), syntax for generic "abs" operation, generic summation
   935 operator \<Sum>;
   936 
   937 * HOL/typedef: simplified package, provide more useful rules (see also
   938 HOL/subset.thy);
   939 
   940 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   941 now expressed as a proper nested rule (old-style tactic scripts may
   942 require atomize_strip_tac to cope with non-atomic premises);
   943 
   944 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   945 to "split_conv" (old name still available for compatibility);
   946 
   947 * HOL: improved concrete syntax for strings (e.g. allows translation
   948 rules with string literals);
   949 
   950 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   951  and Fleuriot's mechanization of analysis, including the transcendental
   952  functions for the reals;
   953 
   954 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   955 
   956 
   957 *** CTT ***
   958 
   959 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   960 "lam" is displayed as TWO lambda-symbols
   961 
   962 * CTT: theory Main now available, containing everything (that is, Bool
   963 and Arith);
   964 
   965 
   966 *** General ***
   967 
   968 * Pure: the Simplifier has been implemented properly as a derived rule
   969 outside of the actual kernel (at last!); the overall performance
   970 penalty in practical applications is about 50%, while reliability of
   971 the Isabelle inference kernel has been greatly improved;
   972 
   973 * print modes "brackets" and "no_brackets" control output of nested =>
   974 (types) and ==> (props); the default behaviour is "brackets";
   975 
   976 * Provers: fast_tac (and friends) now handle actual object-logic rules
   977 as assumptions as well;
   978 
   979 * system: support Poly/ML 4.0;
   980 
   981 * system: isatool install handles KDE version 1 or 2;
   982 
   983 
   984 
   985 New in Isabelle99-1 (October 2000)
   986 ----------------------------------
   987 
   988 *** Overview of INCOMPATIBILITIES ***
   989 
   990 * HOL: simplification of natural numbers is much changed; to partly
   991 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   992 issue the following ML commands:
   993 
   994   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   995   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   996 
   997 * HOL: simplification no longer dives into case-expressions; this is
   998 controlled by "t.weak_case_cong" for each datatype t;
   999 
  1000 * HOL: nat_less_induct renamed to less_induct;
  1001 
  1002 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1003 fixsome to patch .thy and .ML sources automatically;
  1004 
  1005   select_equality  -> some_equality
  1006   select_eq_Ex     -> some_eq_ex
  1007   selectI2EX       -> someI2_ex
  1008   selectI2         -> someI2
  1009   selectI          -> someI
  1010   select1_equality -> some1_equality
  1011   Eps_sym_eq       -> some_sym_eq_trivial
  1012   Eps_eq           -> some_eq_trivial
  1013 
  1014 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1015 
  1016 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1017 instead);
  1018 
  1019 * HOL: the recursion equations generated by 'recdef' are now called
  1020 f.simps instead of f.rules;
  1021 
  1022 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1023 
  1024 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1025 sometimes be needed;
  1026 
  1027 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1028 
  1029 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1030 
  1031 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1032 product is now "<*>" instead of "Times"; the lexicographic product is
  1033 now "<*lex*>" instead of "**";
  1034 
  1035 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1036 of main HOL, but was unused); better use HOL's datatype package;
  1037 
  1038 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1039 the old syntax may be recovered as follows:
  1040 
  1041   syntax (symbols)
  1042     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1043       (infixl "\\<oplus>" 100)
  1044 
  1045 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1046 
  1047 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1048 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1049 internally;
  1050 
  1051 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1052 changed from A/r to A//r;
  1053 
  1054 * ZF: new treatment of arithmetic (nat & int) may break some old
  1055 proofs;
  1056 
  1057 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1058 rulify -> rule_format, elimify -> elim_format, ...);
  1059 
  1060 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1061 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1062 should have to change intro!! to intro? only); replaced "delrule" by
  1063 "rule del";
  1064 
  1065 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1066 
  1067 * Provers: strengthened force_tac by using new first_best_tac;
  1068 
  1069 * LaTeX document preparation: several changes of isabelle.sty (see
  1070 lib/texinputs);
  1071 
  1072 
  1073 *** Document preparation ***
  1074 
  1075 * formal comments (text blocks etc.) in new-style theories may now
  1076 contain antiquotations of thm/prop/term/typ/text to be presented
  1077 according to latex print mode; concrete syntax is like this:
  1078 @{term[show_types] "f(x) = a + x"};
  1079 
  1080 * isatool mkdir provides easy setup of Isabelle session directories,
  1081 including proper document sources;
  1082 
  1083 * generated LaTeX sources are now deleted after successful run
  1084 (isatool document -c); may retain a copy somewhere else via -D option
  1085 of isatool usedir;
  1086 
  1087 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1088 style files, achieving self-contained LaTeX sources and simplifying
  1089 LaTeX debugging;
  1090 
  1091 * old-style theories now produce (crude) LaTeX output as well;
  1092 
  1093 * browser info session directories are now self-contained (may be put
  1094 on WWW server seperately); improved graphs of nested sessions; removed
  1095 graph for 'all sessions';
  1096 
  1097 * several improvements in isabelle style files; \isabellestyle{it}
  1098 produces fake math mode output; \isamarkupheader is now \section by
  1099 default; see lib/texinputs/isabelle.sty etc.;
  1100 
  1101 
  1102 *** Isar ***
  1103 
  1104 * Isar/Pure: local results and corresponding term bindings are now
  1105 subject to Hindley-Milner polymorphism (similar to ML); this
  1106 accommodates incremental type-inference very nicely;
  1107 
  1108 * Isar/Pure: new derived language element 'obtain' supports
  1109 generalized existence reasoning;
  1110 
  1111 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1112 support accumulation of results, without applying any rules yet;
  1113 useful to collect intermediate results without explicit name
  1114 references, and for use with transitivity rules with more than 2
  1115 premises;
  1116 
  1117 * Isar/Pure: scalable support for case-analysis type proofs: new
  1118 'case' language element refers to local contexts symbolically, as
  1119 produced by certain proof methods; internally, case names are attached
  1120 to theorems as "tags";
  1121 
  1122 * Isar/Pure: theory command 'hide' removes declarations from
  1123 class/type/const name spaces;
  1124 
  1125 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1126 indicate potential overloading;
  1127 
  1128 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1129 
  1130 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1131 "{a,b,c}" instead of {a,b,c};
  1132 
  1133 * Isar/Pure now provides its own version of intro/elim/dest
  1134 attributes; useful for building new logics, but beware of confusion
  1135 with the version in Provers/classical;
  1136 
  1137 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1138 case name 'antecedent';
  1139 
  1140 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1141 to the current context is now done automatically);
  1142 
  1143 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1144 for definining proof methods in ML;
  1145 
  1146 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1147 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1148 most cases, one should have to change intro!! to intro? only);
  1149 replaced "delrule" by "rule del";
  1150 
  1151 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1152 'symmetric' attribute (the latter supercedes [RS sym]);
  1153 
  1154 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1155 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1156 well (including splits);
  1157 
  1158 * Isar/Provers: Simplifier and Classical methods now support all kind
  1159 of modifiers used in the past, including 'cong', 'iff', etc.
  1160 
  1161 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1162 of Simplifier and Classical reasoner);
  1163 
  1164 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1165 now support named cases; major packages (inductive, datatype, primrec,
  1166 recdef) support case names and properly name parameters;
  1167 
  1168 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1169 monotonicity conditions are extracted to be proven at end of
  1170 calculations;
  1171 
  1172 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1173 method anyway;
  1174 
  1175 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1176 split_if split_if_asm; datatype package provides theorems foo.splits =
  1177 foo.split foo.split_asm for each datatype;
  1178 
  1179 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1180 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1181 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1182 use "(cases (simplified))" method in proper proof texts);
  1183 
  1184 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1185 
  1186 * Isar: names of theorems etc. may be natural numbers as well;
  1187 
  1188 * Isar: 'pr' command: optional arguments for goals_limit and
  1189 ProofContext.prems_limit; no longer prints theory contexts, but only
  1190 proof states;
  1191 
  1192 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1193 additional print modes to be specified; e.g. "pr(latex)" will print
  1194 proof state according to the Isabelle LaTeX style;
  1195 
  1196 * Isar: improved support for emulating tactic scripts, including proof
  1197 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1198 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1199 (for HOL datatypes);
  1200 
  1201 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1202 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1203 'proof method scripts' have to be in depth-first order;
  1204 
  1205 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1206 
  1207 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1208 should instead use individual commands for printing items
  1209 (print_commands, print_methods etc.);
  1210 
  1211 * Isar: added 'nothing' --- the empty list of theorems;
  1212 
  1213 
  1214 *** HOL ***
  1215 
  1216 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1217 corresponding virtual machine and a specification of its bytecode
  1218 verifier and a lightweight bytecode verifier, including proofs of
  1219 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1220 Cornelia Pusch (see also the homepage of project Bali at
  1221 http://isabelle.in.tum.de/Bali/);
  1222 
  1223 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1224 Clemens Ballarin;
  1225 
  1226 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1227 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1228 Rasmussen;
  1229 
  1230 * HOL/Lattice: fundamental concepts of lattice theory and order
  1231 structures, including duals, properties of bounds versus algebraic
  1232 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1233 Theorem for complete lattices etc.; may also serve as a demonstration
  1234 for abstract algebraic reasoning using axiomatic type classes, and
  1235 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1236 
  1237 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1238 von Oheimb;
  1239 
  1240 * HOL/IMPP: extension of IMP with local variables and mutually
  1241 recursive procedures, by David von Oheimb;
  1242 
  1243 * HOL/Lambda: converted into new-style theory and document;
  1244 
  1245 * HOL/ex/Multiquote: example of multiple nested quotations and
  1246 anti-quotations -- basically a generalized version of de-Bruijn
  1247 representation; very useful in avoiding lifting of operations;
  1248 
  1249 * HOL/record: added general record equality rule to simpset; fixed
  1250 select-update simplification procedure to handle extended records as
  1251 well; admit "r" as field name;
  1252 
  1253 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1254 other numeric types and also as the identity of groups, rings, etc.;
  1255 
  1256 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1257 Types nat and int belong to this axclass;
  1258 
  1259 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1260    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1261    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1262   two terms #m*u and #n*u are replaced by #(m+n)*u
  1263     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1264   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1265     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1266 
  1267 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1268 powerful prover for predicate logic but knows nothing of clasets; see
  1269 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1270 
  1271 * HOL: new version of "case_tac" subsumes both boolean case split and
  1272 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1273 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1274 
  1275 * HOL: simplification no longer dives into case-expressions: only the
  1276 selector expression is simplified, but not the remaining arms; to
  1277 enable full simplification of case-expressions for datatype t, you may
  1278 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1279 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1280 
  1281 * HOL/recdef: the recursion equations generated by 'recdef' for
  1282 function 'f' are now called f.simps instead of f.rules; if all
  1283 termination conditions are proved automatically, these simplification
  1284 rules are added to the simpset, as in primrec; rules may be named
  1285 individually as well, resulting in a separate list of theorems for
  1286 each equation;
  1287 
  1288 * HOL/While is a new theory that provides a while-combinator. It
  1289 permits the definition of tail-recursive functions without the
  1290 provision of a termination measure. The latter is necessary once the
  1291 invariant proof rule for while is applied.
  1292 
  1293 * HOL: new (overloaded) notation for the set of elements below/above
  1294 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1295 
  1296 * HOL: theorems impI, allI, ballI bound as "strip";
  1297 
  1298 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1299 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1300 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1301 
  1302 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1303 
  1304 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1305 main HOL, but was unused);
  1306 
  1307 * HOL: fewer consts declared as global (e.g. have to refer to
  1308 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1309 
  1310 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1311 in case of overlap with user translations (e.g. judgements over
  1312 tuples); (note that the underlying logical represenation is still
  1313 bogus);
  1314 
  1315 
  1316 *** ZF ***
  1317 
  1318 * ZF: simplification automatically cancels common terms in arithmetic
  1319 expressions over nat and int;
  1320 
  1321 * ZF: new treatment of nat to minimize type-checking: all operators
  1322 coerce their operands to a natural number using the function natify,
  1323 making the algebraic laws unconditional;
  1324 
  1325 * ZF: as above, for int: operators coerce their operands to an integer
  1326 using the function intify;
  1327 
  1328 * ZF: the integer library now contains many of the usual laws for the
  1329 orderings, including $<=, and monotonicity laws for $+ and $*;
  1330 
  1331 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1332 simplification;
  1333 
  1334 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1335 to the simplifier and classical reasoner simultaneously;
  1336 
  1337 
  1338 *** General ***
  1339 
  1340 * Provers: blast_tac now handles actual object-logic rules as
  1341 assumptions; note that auto_tac uses blast_tac internally as well;
  1342 
  1343 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1344 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1345 
  1346 * Provers: delrules now handles destruct rules as well (no longer need
  1347 explicit make_elim);
  1348 
  1349 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1350   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1351 use instead the strong form,
  1352   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1353 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1354 from destruct-rules;
  1355 
  1356 * Provers: Simplifier.easy_setup provides a fast path to basic
  1357 Simplifier setup for new object-logics;
  1358 
  1359 * Pure: AST translation rules no longer require constant head on LHS;
  1360 
  1361 * Pure: improved name spaces: ambiguous output is qualified; support
  1362 for hiding of names;
  1363 
  1364 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1365 XSYMBOL_HOME; no longer need to do manual configuration in most
  1366 situations;
  1367 
  1368 * system: compression of ML heaps images may now be controlled via -c
  1369 option of isabelle and isatool usedir (currently only observed by
  1370 Poly/ML);
  1371 
  1372 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1373 useful for remote X11);
  1374 
  1375 * system: provide TAGS file for Isabelle sources;
  1376 
  1377 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1378 order;
  1379 
  1380 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1381 timing flag supersedes proof_timing and Toplevel.trace;
  1382 
  1383 * ML: new combinators |>> and |>>> for incremental transformations
  1384 with secondary results (e.g. certain theory extensions):
  1385 
  1386 * ML: PureThy.add_defs gets additional argument to indicate potential
  1387 overloading (usually false);
  1388 
  1389 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1390 results;
  1391 
  1392 
  1393 
  1394 New in Isabelle99 (October 1999)
  1395 --------------------------------
  1396 
  1397 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1398 
  1399 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1400 are no longer simplified.  (This allows the simplifier to unfold recursive
  1401 functional programs.)  To restore the old behaviour, declare
  1402 
  1403     Delcongs [if_weak_cong];
  1404 
  1405 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1406 complement;
  1407 
  1408 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1409 
  1410 * HOL/datatype: mutual_induct_tac no longer exists --
  1411   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1412 
  1413 * HOL/typedef: fixed type inference for representing set; type
  1414 arguments now have to occur explicitly on the rhs as type constraints;
  1415 
  1416 * ZF: The con_defs part of an inductive definition may no longer refer
  1417 to constants declared in the same theory;
  1418 
  1419 * HOL, ZF: the function mk_cases, generated by the inductive
  1420 definition package, has lost an argument.  To simplify its result, it
  1421 uses the default simpset instead of a supplied list of theorems.
  1422 
  1423 * HOL/List: the constructors of type list are now Nil and Cons;
  1424 
  1425 * Simplifier: the type of the infix ML functions
  1426         setSSolver addSSolver setSolver addSolver
  1427 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1428 for packaging solvers. A solver is created via
  1429         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1430 where the string argument is only a comment.
  1431 
  1432 
  1433 *** Proof tools ***
  1434 
  1435 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1436 decision procedure for linear arithmetic. Currently it is used for
  1437 types `nat', `int', and `real' in HOL (see below); it can, should and
  1438 will be instantiated for other types and logics as well.
  1439 
  1440 * The simplifier now accepts rewrite rules with flexible heads, eg
  1441      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1442   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1443   matching.
  1444 
  1445 
  1446 *** General ***
  1447 
  1448 * New Isabelle/Isar subsystem provides an alternative to traditional
  1449 tactical theorem proving; together with the ProofGeneral/isar user
  1450 interface it offers an interactive environment for developing human
  1451 readable proof documents (Isar == Intelligible semi-automated
  1452 reasoning); for further information see isatool doc isar-ref,
  1453 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1454 
  1455 * improved and simplified presentation of theories: better HTML markup
  1456 (including colors), graph views in several sizes; isatool usedir now
  1457 provides a proper interface for user theories (via -P option); actual
  1458 document preparation based on (PDF)LaTeX is available as well (for
  1459 new-style theories only); see isatool doc system for more information;
  1460 
  1461 * native support for Proof General, both for classic Isabelle and
  1462 Isabelle/Isar;
  1463 
  1464 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1465 using the graph browser tool;
  1466 
  1467 * Isabelle manuals now also available as PDF;
  1468 
  1469 * theory loader rewritten from scratch (may not be fully
  1470 bug-compatible); old loadpath variable has been replaced by show_path,
  1471 add_path, del_path, reset_path functions; new operations such as
  1472 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1473 isatool doc ref);
  1474 
  1475 * improved isatool install: option -k creates KDE application icon,
  1476 option -p DIR installs standalone binaries;
  1477 
  1478 * added ML_PLATFORM setting (useful for cross-platform installations);
  1479 more robust handling of platform specific ML images for SML/NJ;
  1480 
  1481 * the settings environment is now statically scoped, i.e. it is never
  1482 created again in sub-processes invoked from isabelle, isatool, or
  1483 Isabelle;
  1484 
  1485 * path element specification '~~' refers to '$ISABELLE_HOME';
  1486 
  1487 * in locales, the "assumes" and "defines" parts may be omitted if
  1488 empty;
  1489 
  1490 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1491 long arrows);
  1492 
  1493 * new print_mode "HTML";
  1494 
  1495 * new flag show_tags controls display of tags of theorems (which are
  1496 basically just comments that may be attached by some tools);
  1497 
  1498 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1499 mode and goal output format:
  1500 
  1501 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1502 244c244
  1503 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1504 ---
  1505 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1506 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1507 181c181
  1508 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1509 ---
  1510 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1511 
  1512 * function bind_thms stores lists of theorems (cf. bind_thm);
  1513 
  1514 * new shorthand tactics ftac, eatac, datac, fatac;
  1515 
  1516 * qed (and friends) now accept "" as result name; in that case the
  1517 theorem is not stored, but proper checks and presentation of the
  1518 result still apply;
  1519 
  1520 * theorem database now also indexes constants "Trueprop", "all",
  1521 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1522 
  1523 
  1524 *** HOL ***
  1525 
  1526 ** HOL arithmetic **
  1527 
  1528 * There are now decision procedures for linear arithmetic over nat and
  1529 int:
  1530 
  1531 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1532 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1533 are treated as atomic; subformulae not involving type `nat' or `int'
  1534 are ignored; quantified subformulae are ignored unless they are
  1535 positive universal or negative existential. The tactic has to be
  1536 invoked by hand and can be a little bit slow. In particular, the
  1537 running time is exponential in the number of occurrences of `min' and
  1538 `max', and `-' on `nat'.
  1539 
  1540 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1541 (negated) (in)equalities among the premises and the conclusion into
  1542 account (i.e. no compound formulae) and does not know about `min' and
  1543 `max', and `-' on `nat'. It is fast and is used automatically by the
  1544 simplifier.
  1545 
  1546 NB: At the moment, these decision procedures do not cope with mixed
  1547 nat/int formulae where the two parts interact, such as `m < n ==>
  1548 int(m) < int(n)'.
  1549 
  1550 * HOL/Numeral provides a generic theory of numerals (encoded
  1551 efficiently as bit strings); setup for types nat/int/real is in place;
  1552 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1553 int, existing theories and proof scripts may require a few additional
  1554 type constraints;
  1555 
  1556 * integer division and remainder can now be performed on constant
  1557 arguments;
  1558 
  1559 * many properties of integer multiplication, division and remainder
  1560 are now available;
  1561 
  1562 * An interface to the Stanford Validity Checker (SVC) is available through the
  1563 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1564 are proved automatically.  SVC must be installed separately, and its results
  1565 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1566 invocation of the underlying oracle).  For SVC see
  1567   http://verify.stanford.edu/SVC
  1568 
  1569 * IsaMakefile: the HOL-Real target now builds an actual image;
  1570 
  1571 
  1572 ** HOL misc **
  1573 
  1574 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1575 (in Isabelle/Isar) -- by Gertrud Bauer;
  1576 
  1577 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1578 analysis for assembly languages with subtypes;
  1579 
  1580 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1581 -- avoids syntactic ambiguities and treats state, transition, and
  1582 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1583 changed syntax and (many) tactics;
  1584 
  1585 * HOL/inductive: Now also handles more general introduction rules such
  1586   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1587   theorems are now maintained within the theory (maintained via the
  1588   "mono" attribute);
  1589 
  1590 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1591   (using function types) such as
  1592 
  1593   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1594 
  1595 * HOL/record: record_simproc (part of the default simpset) takes care
  1596 of selectors applied to updated records; record_split_tac is no longer
  1597 part of the default claset; update_defs may now be removed from the
  1598 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1599 
  1600   claset_ref () := claset() addSWrapper record_split_wrapper;
  1601   Delsimprocs [record_simproc]
  1602 
  1603 * HOL/typedef: fixed type inference for representing set; type
  1604 arguments now have to occur explicitly on the rhs as type constraints;
  1605 
  1606 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1607 names rather than an ML expression;
  1608 
  1609 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1610 supplied later.  Program schemes can be defined, such as
  1611     "While B C s = (if B s then While B C (C s) else s)"
  1612 where the well-founded relation can be chosen after B and C have been given.
  1613 
  1614 * HOL/List: the constructors of type list are now Nil and Cons;
  1615 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1616 course, ML tools referring to List.list.op # etc. have to be adapted;
  1617 
  1618 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1619 disabled by default; run isabelle with option -m HOL to get back to
  1620 the original Gordon/HOL-style output;
  1621 
  1622 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1623 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1624 
  1625 * HOL basic syntax simplified (more orthogonal): all variants of
  1626 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1627 Eps operator is provided as well: "SOME x. P[x]";
  1628 
  1629 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1630 
  1631 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1632 thus available for user theories;
  1633 
  1634 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1635 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1636 time;
  1637 
  1638 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1639 several times and then mp;
  1640 
  1641 
  1642 *** LK ***
  1643 
  1644 * the notation <<...>> is now available as a notation for sequences of
  1645 formulas;
  1646 
  1647 * the simplifier is now installed
  1648 
  1649 * the axiom system has been generalized (thanks to Soren Heilmann)
  1650 
  1651 * the classical reasoner now has a default rule database
  1652 
  1653 
  1654 *** ZF ***
  1655 
  1656 * new primrec section allows primitive recursive functions to be given
  1657 directly (as in HOL) over datatypes and the natural numbers;
  1658 
  1659 * new tactics induct_tac and exhaust_tac for induction (or case
  1660 analysis) over datatypes and the natural numbers;
  1661 
  1662 * the datatype declaration of type T now defines the recursor T_rec;
  1663 
  1664 * simplification automatically does freeness reasoning for datatype
  1665 constructors;
  1666 
  1667 * automatic type-inference, with AddTCs command to insert new
  1668 type-checking rules;
  1669 
  1670 * datatype introduction rules are now added as Safe Introduction rules
  1671 to the claset;
  1672 
  1673 * the syntax "if P then x else y" is now available in addition to
  1674 if(P,x,y);
  1675 
  1676 
  1677 *** Internal programming interfaces ***
  1678 
  1679 * tuned simplifier trace output; new flag debug_simp;
  1680 
  1681 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1682 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1683 
  1684 * AxClass.axclass_tac lost the theory argument;
  1685 
  1686 * tuned current_goals_markers semantics: begin / end goal avoids
  1687 printing empty lines;
  1688 
  1689 * removed prs and prs_fn hook, which was broken because it did not
  1690 include \n in its semantics, forcing writeln to add one
  1691 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1692 string -> unit if you really want to output text without newline;
  1693 
  1694 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1695 plain output, interface builders may have to enable 'isabelle_font'
  1696 mode to get Isabelle font glyphs as before;
  1697 
  1698 * refined token_translation interface; INCOMPATIBILITY: output length
  1699 now of type real instead of int;
  1700 
  1701 * theory loader actions may be traced via new ThyInfo.add_hook
  1702 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1703 your own database of information attached to *whole* theories -- as
  1704 opposed to intra-theory data slots offered via TheoryDataFun;
  1705 
  1706 * proper handling of dangling sort hypotheses (at last!);
  1707 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1708 extra sort hypotheses that can be witnessed from the type signature;
  1709 the force_strip_shyps flag is gone, any remaining shyps are simply
  1710 left in the theorem (with a warning issued by strip_shyps_warning);
  1711 
  1712 
  1713 
  1714 New in Isabelle98-1 (October 1998)
  1715 ----------------------------------
  1716 
  1717 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1718 
  1719 * several changes of automated proof tools;
  1720 
  1721 * HOL: major changes to the inductive and datatype packages, including
  1722 some minor incompatibilities of theory syntax;
  1723 
  1724 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1725 called `inj_on';
  1726 
  1727 * HOL: removed duplicate thms in Arith:
  1728   less_imp_add_less  should be replaced by  trans_less_add1
  1729   le_imp_add_le      should be replaced by  trans_le_add1
  1730 
  1731 * HOL: unary minus is now overloaded (new type constraints may be
  1732 required);
  1733 
  1734 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1735 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1736 now taken as an integer constant.
  1737 
  1738 * Pure: ML function 'theory_of' renamed to 'theory';
  1739 
  1740 
  1741 *** Proof tools ***
  1742 
  1743 * Simplifier:
  1744   1. Asm_full_simp_tac is now more aggressive.
  1745      1. It will sometimes reorient premises if that increases their power to
  1746         simplify.
  1747      2. It does no longer proceed strictly from left to right but may also
  1748         rotate premises to achieve further simplification.
  1749      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1750      old Asm_full_simp_tac in that it does not rotate premises.
  1751   2. The simplifier now knows a little bit about nat-arithmetic.
  1752 
  1753 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1754 allows for selected deletion of wrappers, by introduction of names for
  1755 wrapper functionals.  This implies that addbefore, addSbefore,
  1756 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1757 and that adding two tactics with the same name overwrites the first
  1758 one (emitting a warning).
  1759   type wrapper = (int -> tactic) -> (int -> tactic)
  1760   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1761   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1762   delWrapper, delSWrapper: claset *  string            -> claset
  1763   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1764 
  1765 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1766 semantics; addbefore now affects only the unsafe part of step_tac
  1767 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1768 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1769 by Force_tac;
  1770 
  1771 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1772 compWrapper; added safe wrapper (and access functions for it);
  1773 
  1774 * HOL/split_all_tac is now much faster and fails if there is nothing
  1775 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1776 and the names of the automatically generated variables have changed.
  1777 split_all_tac has moved within claset() from unsafe wrappers to safe
  1778 wrappers, which means that !!-bound variables are split much more
  1779 aggressively, and safe_tac and clarify_tac now split such variables.
  1780 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1781 Note: the same holds for record_split_tac, which does the job of
  1782 split_all_tac for record fields.
  1783 
  1784 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1785 permanently to the default simpset using Addsplits just like
  1786 Addsimps. They can be removed via Delsplits just like
  1787 Delsimps. Lower-case versions are also available.
  1788 
  1789 * HOL/Simplifier: The rule split_if is now part of the default
  1790 simpset. This means that the simplifier will eliminate all occurrences
  1791 of if-then-else in the conclusion of a goal. To prevent this, you can
  1792 either remove split_if completely from the default simpset by
  1793 `Delsplits [split_if]' or remove it in a specific call of the
  1794 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1795 other case splitting rules to/from the default simpset: every datatype
  1796 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1797 t is the name of the datatype).
  1798 
  1799 * Classical reasoner / Simplifier combination: new force_tac (and
  1800 derivatives Force_tac, force) combines rewriting and classical
  1801 reasoning (and whatever other tools) similarly to auto_tac, but is
  1802 aimed to solve the given subgoal completely.
  1803 
  1804 
  1805 *** General ***
  1806 
  1807 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1808 and `goalw': the theory is no longer needed as an explicit argument -
  1809 the current theory context is used; assumptions are no longer returned
  1810 at the ML-level unless one of them starts with ==> or !!; it is
  1811 recommended to convert to these new commands using isatool fixgoal
  1812 (backup your sources first!);
  1813 
  1814 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1815 the current theory context, and 'theory' to lookup stored theories;
  1816 
  1817 * new theory section 'locale' for declaring constants, assumptions and
  1818 definitions that have local scope;
  1819 
  1820 * new theory section 'nonterminals' for purely syntactic types;
  1821 
  1822 * new theory section 'setup' for generic ML setup functions
  1823 (e.g. package initialization);
  1824 
  1825 * the distribution now includes Isabelle icons: see
  1826 lib/logo/isabelle-{small,tiny}.xpm;
  1827 
  1828 * isatool install - install binaries with absolute references to
  1829 ISABELLE_HOME/bin;
  1830 
  1831 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1832 
  1833 * print mode 'emacs' reserved for Isamode;
  1834 
  1835 * support multiple print (ast) translations per constant name;
  1836 
  1837 * theorems involving oracles are now printed with a suffixed [!];
  1838 
  1839 
  1840 *** HOL ***
  1841 
  1842 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1843 
  1844 * HOL/inductive package reorganized and improved: now supports mutual
  1845 definitions such as
  1846 
  1847   inductive EVEN ODD
  1848     intrs
  1849       null "0 : EVEN"
  1850       oddI "n : EVEN ==> Suc n : ODD"
  1851       evenI "n : ODD ==> Suc n : EVEN"
  1852 
  1853 new theorem list "elims" contains an elimination rule for each of the
  1854 recursive sets; inductive definitions now handle disjunctive premises
  1855 correctly (also ZF);
  1856 
  1857 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1858 "mutual_induct" no longer exists - the induction rule is always
  1859 contained in "induct";
  1860 
  1861 
  1862 * HOL/datatype package re-implemented and greatly improved: now
  1863 supports mutually recursive datatypes such as
  1864 
  1865   datatype
  1866     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1867             | SUM ('a aexp) ('a aexp)
  1868             | DIFF ('a aexp) ('a aexp)
  1869             | NUM 'a
  1870   and
  1871     'a bexp = LESS ('a aexp) ('a aexp)
  1872             | AND ('a bexp) ('a bexp)
  1873             | OR ('a bexp) ('a bexp)
  1874 
  1875 as well as indirectly recursive datatypes such as
  1876 
  1877   datatype
  1878     ('a, 'b) term = Var 'a
  1879                   | App 'b ((('a, 'b) term) list)
  1880 
  1881 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1882 induction on mutually / indirectly recursive datatypes.
  1883 
  1884 Primrec equations are now stored in theory and can be accessed via
  1885 <function_name>.simps.
  1886 
  1887 INCOMPATIBILITIES:
  1888 
  1889   - Theories using datatypes must now have theory Datatype as an
  1890     ancestor.
  1891   - The specific <typename>.induct_tac no longer exists - use the
  1892     generic induct_tac instead.
  1893   - natE has been renamed to nat.exhaust - use exhaust_tac
  1894     instead of res_inst_tac ... natE. Note that the variable
  1895     names in nat.exhaust differ from the names in natE, this
  1896     may cause some "fragile" proofs to fail.
  1897   - The theorems split_<typename>_case and split_<typename>_case_asm
  1898     have been renamed to <typename>.split and <typename>.split_asm.
  1899   - Since default sorts of type variables are now handled correctly,
  1900     some datatype definitions may have to be annotated with explicit
  1901     sort constraints.
  1902   - Primrec definitions no longer require function name and type
  1903     of recursive argument.
  1904 
  1905 Consider using isatool fixdatatype to adapt your theories and proof
  1906 scripts to the new package (backup your sources first!).
  1907 
  1908 
  1909 * HOL/record package: considerably improved implementation; now
  1910 includes concrete syntax for record types, terms, updates; theorems
  1911 for surjective pairing and splitting !!-bound record variables; proof
  1912 support is as follows:
  1913 
  1914   1) standard conversions (selectors or updates applied to record
  1915 constructor terms) are part of the standard simpset;
  1916 
  1917   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1918 made part of standard simpset and claset via addIffs;
  1919 
  1920   3) a tactic for record field splitting (record_split_tac) is part of
  1921 the standard claset (addSWrapper);
  1922 
  1923 To get a better idea about these rules you may retrieve them via
  1924 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1925 the name of your record type.
  1926 
  1927 The split tactic 3) conceptually simplifies by the following rule:
  1928 
  1929   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1930 
  1931 Thus any record variable that is bound by meta-all will automatically
  1932 blow up into some record constructor term, consequently the
  1933 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1934 solve record problems automatically.
  1935 
  1936 
  1937 * reorganized the main HOL image: HOL/Integ and String loaded by
  1938 default; theory Main includes everything;
  1939 
  1940 * automatic simplification of integer sums and comparisons, using cancellation;
  1941 
  1942 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1943 
  1944 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1945 
  1946 * many new identities for unions, intersections, set difference, etc.;
  1947 
  1948 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1949 called split_if, split_split, split_sum_case and split_nat_case (to go
  1950 with add/delsplits);
  1951 
  1952 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1953 (?x::unit) = (); this is made part of the default simpset, which COULD
  1954 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1955 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1956 unit_abs_eta_conv is added in order to counter the effect of
  1957 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1958 %u.f();
  1959 
  1960 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1961 makes more sense);
  1962 
  1963 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1964   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1965   disjointness reasoning but breaking a few old proofs.
  1966 
  1967 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1968 to 'converse' from 'inverse' (for compatibility with ZF and some
  1969 literature);
  1970 
  1971 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1972 the well-founded relation;
  1973 
  1974 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1975     Compl A.  The "Compl" syntax remains available as input syntax for this
  1976     release ONLY.
  1977 
  1978 * HOL/Update: new theory of function updates:
  1979     f(a:=b) == %x. if x=a then b else f x
  1980 may also be iterated as in f(a:=b,c:=d,...);
  1981 
  1982 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1983 
  1984 * HOL/List:
  1985   - new function list_update written xs[i:=v] that updates the i-th
  1986     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1987   - new function `upt' written [i..j(] which generates the list
  1988     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1989     bound write [i..j], which is a shorthand for [i..j+1(].
  1990   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1991 
  1992 * HOL/Arith:
  1993   - removed 'pred' (predecessor) function;
  1994   - generalized some theorems about n-1;
  1995   - many new laws about "div" and "mod";
  1996   - new laws about greatest common divisors (see theory ex/Primes);
  1997 
  1998 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1999 instead of "inverse";
  2000 
  2001 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2002   of the multiset ordering;
  2003 
  2004 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2005   (not included by default);
  2006 
  2007 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2008 
  2009 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2010   programs, i.e. different program variables may have different types.
  2011 
  2012 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2013   [previously, this check worked only if the rewrite rule was unconditional]
  2014   Now rew can involve either definitions or equalities (either == or =).
  2015 
  2016 
  2017 *** ZF ***
  2018 
  2019 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2020   only the theorems proved on ZF.ML;
  2021 
  2022 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2023   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2024   disjointness reasoning but breaking a few old proofs.
  2025 
  2026 * ZF/Update: new theory of function updates
  2027     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2028   may also be iterated as in f(a:=b,c:=d,...);
  2029 
  2030 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2031 
  2032 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2033   [previously, this check worked only if the rewrite rule was unconditional]
  2034   Now rew can involve either definitions or equalities (either == or =).
  2035 
  2036 * case_tac provided for compatibility with HOL
  2037     (like the old excluded_middle_tac, but with subgoals swapped)
  2038 
  2039 
  2040 *** Internal programming interfaces ***
  2041 
  2042 * Pure: several new basic modules made available for general use, see
  2043 also src/Pure/README;
  2044 
  2045 * improved the theory data mechanism to support encapsulation (data
  2046 kind name replaced by private Object.kind, acting as authorization
  2047 key); new type-safe user interface via functor TheoryDataFun; generic
  2048 print_data function becomes basically useless;
  2049 
  2050 * removed global_names compatibility flag -- all theory declarations
  2051 are qualified by default;
  2052 
  2053 * module Pure/Syntax now offers quote / antiquote translation
  2054 functions (useful for Hoare logic etc. with implicit dependencies);
  2055 see HOL/ex/Antiquote for an example use;
  2056 
  2057 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2058 cterm -> thm;
  2059 
  2060 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2061 subgoal;
  2062 
  2063 * Display.print_goals function moved to Locale.print_goals;
  2064 
  2065 * standard print function for goals supports current_goals_markers
  2066 variable for marking begin of proof, end of proof, start of goal; the
  2067 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2068 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2069 for example;
  2070 
  2071 
  2072 
  2073 New in Isabelle98 (January 1998)
  2074 --------------------------------
  2075 
  2076 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2077 
  2078 * changed lexical syntax of terms / types: dots made part of long
  2079 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2080 
  2081 * simpset (and claset) reference variable replaced by functions
  2082 simpset / simpset_ref;
  2083 
  2084 * no longer supports theory aliases (via merge) and non-trivial
  2085 implicit merge of thms' signatures;
  2086 
  2087 * most internal names of constants changed due to qualified names;
  2088 
  2089 * changed Pure/Sequence interface (see Pure/seq.ML);
  2090 
  2091 
  2092 *** General Changes ***
  2093 
  2094 * hierachically structured name spaces (for consts, types, axms, thms
  2095 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2096 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2097 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2098 long_names for fully qualified output names; NOTE: ML programs
  2099 (special tactics, packages etc.) referring to internal names may have
  2100 to be adapted to cope with fully qualified names; in case of severe
  2101 backward campatibility problems try setting 'global_names' at compile
  2102 time to have enrything declared within a flat name space; one may also
  2103 fine tune name declarations in theories via the 'global' and 'local'
  2104 section;
  2105 
  2106 * reimplemented the implicit simpset and claset using the new anytype
  2107 data filed in signatures; references simpset:simpset ref etc. are
  2108 replaced by functions simpset:unit->simpset and
  2109 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2110 to patch your ML files accordingly;
  2111 
  2112 * HTML output now includes theory graph data for display with Java
  2113 applet or isatool browser; data generated automatically via isatool
  2114 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2115 
  2116 * defs may now be conditional; improved rewrite_goals_tac to handle
  2117 conditional equations;
  2118 
  2119 * defs now admits additional type arguments, using TYPE('a) syntax;
  2120 
  2121 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2122 creates a new theory node; implicit merge of thms' signatures is
  2123 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2124 transfer:theory->thm->thm in (rare) cases;
  2125 
  2126 * improved handling of draft signatures / theories; draft thms (and
  2127 ctyps, cterms) are automatically promoted to real ones;
  2128 
  2129 * slightly changed interfaces for oracles: admit many per theory, named
  2130 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2131 
  2132 * print_goals: optional output of const types (set show_consts and
  2133 show_types);
  2134 
  2135 * improved output of warnings (###) and errors (***);
  2136 
  2137 * subgoal_tac displays a warning if the new subgoal has type variables;
  2138 
  2139 * removed old README and Makefiles;
  2140 
  2141 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2142 
  2143 * removed obsolete init_pps and init_database;
  2144 
  2145 * deleted the obsolete tactical STATE, which was declared by
  2146     fun STATE tacfun st = tacfun st st;
  2147 
  2148 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2149 (which abbreviates $HOME);
  2150 
  2151 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2152 use isatool fixseq to adapt your ML programs (this works for fully
  2153 qualified references to the Sequence structure only!);
  2154 
  2155 * use_thy no longer requires writable current directory; it always
  2156 reloads .ML *and* .thy file, if either one is out of date;
  2157 
  2158 
  2159 *** Classical Reasoner ***
  2160 
  2161 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2162 tactics that use classical reasoning to simplify a subgoal without
  2163 splitting it into several subgoals;
  2164 
  2165 * Safe_tac: like safe_tac but uses the default claset;
  2166 
  2167 
  2168 *** Simplifier ***
  2169 
  2170 * added simplification meta rules:
  2171     (asm_)(full_)simplify: simpset -> thm -> thm;
  2172 
  2173 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2174 logics (again);
  2175 
  2176 * added prems argument to simplification procedures;
  2177 
  2178 * HOL, FOL, ZF: added infix function `addsplits':
  2179   instead of `<simpset> setloop (split_tac <thms>)'
  2180   you can simply write `<simpset> addsplits <thms>'
  2181 
  2182 
  2183 *** Syntax ***
  2184 
  2185 * TYPE('a) syntax for type reflection terms;
  2186 
  2187 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2188 
  2189 * pretty printer: changed order of mixfix annotation preference (again!);
  2190 
  2191 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2192 
  2193 
  2194 *** HOL ***
  2195 
  2196 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2197   with `addloop' of the simplifier to faciliate case splitting in premises.
  2198 
  2199 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2200 
  2201 * HOL/Auth: new protocol proofs including some for the Internet
  2202   protocol TLS;
  2203 
  2204 * HOL/Map: new theory of `maps' a la VDM;
  2205 
  2206 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2207 cancelling out common nat summands from =, <, <= (in)equalities, or
  2208 differences; simplification procedures nat_cancel_factor for
  2209 cancelling common factor from =, <, <= (in)equalities over natural
  2210 sums; nat_cancel contains both kinds of procedures, it is installed by
  2211 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2212 
  2213 * HOL/simplifier: terms of the form
  2214   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2215   are rewritten to
  2216   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2217   and those of the form
  2218   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2219   are rewritten to
  2220   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2221 
  2222 * HOL/datatype
  2223   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2224 
  2225   P(t_case f1 ... fn x) =
  2226      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2227         ...
  2228        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2229      )
  2230 
  2231   and a theorem `split_t_case_asm' of the form
  2232 
  2233   P(t_case f1 ... fn x) =
  2234     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2235         ...
  2236        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2237      )
  2238   which can be added to a simpset via `addsplits'. The existing theorems
  2239   expand_list_case and expand_option_case have been renamed to
  2240   split_list_case and split_option_case.
  2241 
  2242 * HOL/Arithmetic:
  2243   - `pred n' is automatically converted to `n-1'.
  2244     Users are strongly encouraged not to use `pred' any longer,
  2245     because it will disappear altogether at some point.
  2246   - Users are strongly encouraged to write "0 < n" rather than
  2247     "n ~= 0". Theorems and proof tools have been modified towards this
  2248     `standard'.
  2249 
  2250 * HOL/Lists:
  2251   the function "set_of_list" has been renamed "set" (and its theorems too);
  2252   the function "nth" now takes its arguments in the reverse order and
  2253   has acquired the infix notation "!" as in "xs!n".
  2254 
  2255 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2256 
  2257 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2258   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2259 
  2260 * HOL/record: extensible records with schematic structural subtyping
  2261 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2262 still lacks various theorems and concrete record syntax;
  2263 
  2264 
  2265 *** HOLCF ***
  2266 
  2267 * removed "axioms" and "generated by" sections;
  2268 
  2269 * replaced "ops" section by extended "consts" section, which is capable of
  2270   handling the continuous function space "->" directly;
  2271 
  2272 * domain package:
  2273   . proves theorems immediately and stores them in the theory,
  2274   . creates hierachical name space,
  2275   . now uses normal mixfix annotations (instead of cinfix...),
  2276   . minor changes to some names and values (for consistency),
  2277   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2278   . separator between mutual domain defs: changed "," to "and",
  2279   . improved handling of sort constraints;  now they have to
  2280     appear on the left-hand side of the equations only;
  2281 
  2282 * fixed LAM <x,y,zs>.b syntax;
  2283 
  2284 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2285 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2286 
  2287 
  2288 *** FOL and ZF ***
  2289 
  2290 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2291   with `addloop' of the simplifier to faciliate case splitting in premises.
  2292 
  2293 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2294 in HOL, they strip ALL and --> from proved theorems;
  2295 
  2296 
  2297 
  2298 New in Isabelle94-8 (May 1997)
  2299 ------------------------------
  2300 
  2301 *** General Changes ***
  2302 
  2303 * new utilities to build / run / maintain Isabelle etc. (in parts
  2304 still somewhat experimental); old Makefiles etc. still functional;
  2305 
  2306 * new 'Isabelle System Manual';
  2307 
  2308 * INSTALL text, together with ./configure and ./build scripts;
  2309 
  2310 * reimplemented type inference for greater efficiency, better error
  2311 messages and clean internal interface;
  2312 
  2313 * prlim command for dealing with lots of subgoals (an easier way of
  2314 setting goals_limit);
  2315 
  2316 
  2317 *** Syntax ***
  2318 
  2319 * supports alternative (named) syntax tables (parser and pretty
  2320 printer); internal interface is provided by add_modesyntax(_i);
  2321 
  2322 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2323 be used in conjunction with the Isabelle symbol font; uses the
  2324 "symbols" syntax table;
  2325 
  2326 * added token_translation interface (may translate name tokens in
  2327 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2328 the current print_mode); IMPORTANT: user print translation functions
  2329 are responsible for marking newly introduced bounds
  2330 (Syntax.mark_boundT);
  2331 
  2332 * token translations for modes "xterm" and "xterm_color" that display
  2333 names in bold, underline etc. or colors (which requires a color
  2334 version of xterm);
  2335 
  2336 * infixes may now be declared with names independent of their syntax;
  2337 
  2338 * added typed_print_translation (like print_translation, but may
  2339 access type of constant);
  2340 
  2341 
  2342 *** Classical Reasoner ***
  2343 
  2344 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2345 some limitations.  Blast_tac...
  2346   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2347   + ignores elimination rules that don't have the correct format
  2348         (the conclusion MUST be a formula variable)
  2349   + ignores types, which can make HOL proofs fail
  2350   + rules must not require higher-order unification, e.g. apply_type in ZF
  2351     [message "Function Var's argument not a bound variable" relates to this]
  2352   + its proof strategy is more general but can actually be slower
  2353 
  2354 * substitution with equality assumptions no longer permutes other
  2355 assumptions;
  2356 
  2357 * minor changes in semantics of addafter (now called addaltern); renamed
  2358 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2359 (and access functions for it);
  2360 
  2361 * improved combination of classical reasoner and simplifier:
  2362   + functions for handling clasimpsets
  2363   + improvement of addss: now the simplifier is called _after_ the
  2364     safe steps.
  2365   + safe variant of addss called addSss: uses safe simplifications
  2366     _during_ the safe steps. It is more complete as it allows multiple
  2367     instantiations of unknowns (e.g. with slow_tac).
  2368 
  2369 *** Simplifier ***
  2370 
  2371 * added interface for simplification procedures (functions that
  2372 produce *proven* rewrite rules on the fly, depending on current
  2373 redex);
  2374 
  2375 * ordering on terms as parameter (used for ordered rewriting);
  2376 
  2377 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2378 
  2379 * the solver is now split into a safe and an unsafe part.
  2380 This should be invisible for the normal user, except that the
  2381 functions setsolver and addsolver have been renamed to setSolver and
  2382 addSolver; added safe_asm_full_simp_tac;
  2383 
  2384 
  2385 *** HOL ***
  2386 
  2387 * a generic induction tactic `induct_tac' which works for all datatypes and
  2388 also for type `nat';
  2389 
  2390 * a generic case distinction tactic `exhaust_tac' which works for all
  2391 datatypes and also for type `nat';
  2392 
  2393 * each datatype comes with a function `size';
  2394 
  2395 * patterns in case expressions allow tuple patterns as arguments to
  2396 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2397 
  2398 * primrec now also works with type nat;
  2399 
  2400 * recdef: a new declaration form, allows general recursive functions to be
  2401 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2402 
  2403 * the constant for negation has been renamed from "not" to "Not" to
  2404 harmonize with FOL, ZF, LK, etc.;
  2405 
  2406 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2407 infinite lists;
  2408 
  2409 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2410 
  2411 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2412 problems in commutative rings, using axiomatic type classes for + and *;
  2413 
  2414 * more examples in HOL/MiniML and HOL/Auth;
  2415 
  2416 * more default rewrite rules for quantifiers, union/intersection;
  2417 
  2418 * a new constant `arbitrary == @x.False';
  2419 
  2420 * HOLCF/IOA replaces old HOL/IOA;
  2421 
  2422 * HOLCF changes: derived all rules and arities
  2423   + axiomatic type classes instead of classes
  2424   + typedef instead of faking type definitions
  2425   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2426   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2427   + eliminated the types void, one, tr
  2428   + use unit lift and bool lift (with translations) instead of one and tr
  2429   + eliminated blift from Lift3.thy (use Def instead of blift)
  2430   all eliminated rules are derived as theorems --> no visible changes ;
  2431 
  2432 
  2433 *** ZF ***
  2434 
  2435 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2436 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2437 as ZF_cs addSIs [equalityI];
  2438 
  2439 
  2440 
  2441 New in Isabelle94-7 (November 96)
  2442 ---------------------------------
  2443 
  2444 * allowing negative levels (as offsets) in prlev and choplev;
  2445 
  2446 * super-linear speedup for large simplifications;
  2447 
  2448 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2449 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2450 FAIL); can suppress it using the command Delsimps (ex_simps @
  2451 all_simps); De Morgan laws are also now included, by default;
  2452 
  2453 * improved printing of ==>  :  ~:
  2454 
  2455 * new object-logic "Sequents" adds linear logic, while replacing LK
  2456 and Modal (thanks to Sara Kalvala);
  2457 
  2458 * HOL/Auth: correctness proofs for authentication protocols;
  2459 
  2460 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2461 examples on HOL/Auth);
  2462 
  2463 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2464 the rewriter and classical reasoner simultaneously;
  2465 
  2466 * function uresult no longer returns theorems in "standard" format;
  2467 regain previous version by: val uresult = standard o uresult;
  2468 
  2469 
  2470 
  2471 New in Isabelle94-6
  2472 -------------------
  2473 
  2474 * oracles -- these establish an interface between Isabelle and trusted
  2475 external reasoners, which may deliver results as theorems;
  2476 
  2477 * proof objects (in particular record all uses of oracles);
  2478 
  2479 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2480 
  2481 * "constdefs" section in theory files;
  2482 
  2483 * "primrec" section (HOL) no longer requires names;
  2484 
  2485 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2486 
  2487 
  2488 
  2489 New in Isabelle94-5
  2490 -------------------
  2491 
  2492 * reduced space requirements;
  2493 
  2494 * automatic HTML generation from theories;
  2495 
  2496 * theory files no longer require "..." (quotes) around most types;
  2497 
  2498 * new examples, including two proofs of the Church-Rosser theorem;
  2499 
  2500 * non-curried (1994) version of HOL is no longer distributed;
  2501 
  2502 
  2503 
  2504 New in Isabelle94-4
  2505 -------------------
  2506 
  2507 * greatly reduced space requirements;
  2508 
  2509 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2510 
  2511 * searchable theorem database (see the section "Retrieving theorems" on
  2512 page 8 of the Reference Manual);
  2513 
  2514 * new examples, including Grabczewski's monumental case study of the
  2515 Axiom of Choice;
  2516 
  2517 * The previous version of HOL renamed to Old_HOL;
  2518 
  2519 * The new version of HOL (previously called CHOL) uses a curried syntax
  2520 for functions.  Application looks like f a b instead of f(a,b);
  2521 
  2522 * Mutually recursive inductive definitions finally work in HOL;
  2523 
  2524 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2525 translates to the operator "split";
  2526 
  2527 
  2528 
  2529 New in Isabelle94-3
  2530 -------------------
  2531 
  2532 * new infix operator, addss, allowing the classical reasoner to
  2533 perform simplification at each step of its search.  Example:
  2534         fast_tac (cs addss ss)
  2535 
  2536 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2537 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2538 look like (a,b) instead of <a,b>;
  2539 
  2540 * PLEASE NOTE: CHOL will eventually replace HOL!
  2541 
  2542 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2543 It translates to the operator "split".  A new theory of integers is available;
  2544 
  2545 * In ZF, integer numerals now denote two's-complement binary integers.
  2546 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2547 
  2548 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2549 of the Axiom of Choice;
  2550 
  2551 
  2552 
  2553 New in Isabelle94-2
  2554 -------------------
  2555 
  2556 * Significantly faster resolution;
  2557 
  2558 * the different sections in a .thy file can now be mixed and repeated
  2559 freely;
  2560 
  2561 * Database of theorems for FOL, HOL and ZF.  New
  2562 commands including qed, qed_goal and bind_thm store theorems in the database.
  2563 
  2564 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2565 a given theory (thms_of), or find out what theory a theorem was proved in
  2566 (theory_of_thm);
  2567 
  2568 * Bugs fixed in the inductive definition and datatype packages;
  2569 
  2570 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2571 and HOL_dup_cs obsolete;
  2572 
  2573 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2574 have been removed;
  2575 
  2576 * Simpler definition of function space in ZF;
  2577 
  2578 * new results about cardinal and ordinal arithmetic in ZF;
  2579 
  2580 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2581 types;
  2582 
  2583 
  2584 $Id$