NEWS
author ballarin
Thu Feb 19 16:44:21 2004 +0100 (2004-02-19)
changeset 14399 dc677b35e54f
parent 14398 c5c47703f763
child 14401 477380c74c1d
permissions -rw-r--r--
New lemmas about inversion of restricted functions.
HOL-Algebra: new locale "ring" for non-commutative rings.
     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 *** Isar ***
    49 
    50 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    51   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    52     locales are no longer forced to write Isar proof scripts.
    53     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    54     emulations.
    55   - INCOMPATIBILITY: names of variables to be instantiated may no
    56     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    57     This is consistent with the instantiation attribute "where".
    58 
    59 * Attributes "where" and "of":
    60   - Now take type variables of instantiated theorem into account when reading
    61     the instantiation string.  This fixes a bug that caused instantiated
    62     theorems to have too special types in some circumstances.
    63   - "where" permits explicit instantiations of type variables.
    64 
    65 * Calculation commands "moreover" and "also":
    66   Do not reset facts ("this") any more.
    67 
    68 * Locales:
    69   - Goal statements involving the context element "includes" no longer
    70     generate theorems with internal delta predicates (those ending on
    71     "_axioms") in the premise.
    72     Resolve particular premise with <locale>.intro to obtain old form.
    73   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    74     specification and "includes" elements in goal statement.
    75   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    76     [intro?] and [elim?] (respectively) by default.
    77 
    78 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    79   (Isar) contexts.
    80 
    81 *** HOL ***
    82 
    83 * Simplifier:
    84   - Much improved handling of linear and partial orders.
    85     Reasoners for linear and partial orders are set up for type classes
    86     "linorder" and "order" respectively, and are added to the default simpset
    87     as solvers.  This means that the simplifier can build transitivity chains
    88     to solve goals from the assumptions.
    89   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
    90     of blast or auto after simplification become unnecessary because the goal
    91     is solved by simplification already.
    92 
    93 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
    94     all proved in axiomatic type classes for semirings, rings and fields.
    95 
    96 * Numerics:
    97   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
    98     now formalized using the Ring_and_Field theory mentioned above. 
    99   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   100     than before, because now they are set up once in a generic manner.
   101   - INCOMPATIBILITY: many type-specific instances of laws proved in 
   102     Ring_and_Field are no longer available.
   103 
   104 * Type "rat" of the rational numbers is now availabe in HOL-Complex.
   105 
   106 * Records:
   107   - Record types are now by default printed with their type abbreviation
   108     instead of the list of all field types. This can be configured via
   109     the reference "print_record_type_abbr".
   110   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   111     (not enabled by default).
   112   - Tactic "record_split_simp_tac" to split and simplify records added.
   113  
   114 * 'specification' command added, allowing for definition by
   115   specification.  There is also an 'ax_specification' command that
   116   introduces the new constants axiomatically.
   117 
   118 * arith(_tac) is now able to generate counterexamples for reals as well.
   119 
   120 * HOL-Algebra: new locale "ring" for non-commutative rings.
   121 
   122 * SET-Protocol: formalization and verification of the SET protocol suite;
   123 
   124 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   125  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   126 
   127 * Unions and Intersections:
   128   The x-symbol output syntax of UN and INT has been changed
   129   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   130   i.e. the index formulae has become a subscript, like in normal math.
   131   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   132   The subscript version is also accepted as input syntax.
   133 
   134 
   135 New in Isabelle2003 (May 2003)
   136 --------------------------------
   137 
   138 *** General ***
   139 
   140 * Provers/simplifier:
   141 
   142   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   143     Assumptions are now subject to complete mutual simplification,
   144     not just from left to right. The simplifier now preserves
   145     the order of assumptions.
   146 
   147     Potential INCOMPATIBILITY:
   148 
   149     -- simp sometimes diverges where the old version did
   150        not, e.g. invoking simp on the goal
   151 
   152         [| P (f x); y = x; f x = f y |] ==> Q
   153 
   154        now gives rise to the infinite reduction sequence
   155 
   156         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   157 
   158        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   159        kind of problem.
   160 
   161     -- Tactics combining classical reasoner and simplification (such as auto)
   162        are also affected by this change, because many of them rely on
   163        simp. They may sometimes diverge as well or yield a different numbers
   164        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   165        in case of problems. Sometimes subsequent calls to the classical
   166        reasoner will fail because a preceeding call to the simplifier too
   167        eagerly simplified the goal, e.g. deleted redundant premises.
   168 
   169   - The simplifier trace now shows the names of the applied rewrite rules
   170 
   171   - You can limit the number of recursive invocations of the simplifier
   172     during conditional rewriting (where the simplifie tries to solve the
   173     conditions before applying the rewrite rule):
   174     ML "simp_depth_limit := n"
   175     where n is an integer. Thus you can force termination where previously
   176     the simplifier would diverge.
   177 
   178   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   179 
   180   - No longer aborts on failed congruence proof.  Instead, the
   181     congruence is ignored.
   182 
   183 * Pure: New generic framework for extracting programs from constructive
   184   proofs. See HOL/Extraction.thy for an example instantiation, as well
   185   as HOL/Extraction for some case studies.
   186 
   187 * Pure: The main goal of the proof state is no longer shown by default, only
   188 the subgoals. This behaviour is controlled by a new flag.
   189    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   190 (ML: Proof.show_main_goal).
   191 
   192 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   193 rules whose conclusion matches subgoal 1:
   194       PG menu: Isabelle/Isar -> Show me -> matching rules
   195 The rules are ordered by how closely they match the subgoal.
   196 In particular, rules that solve a subgoal outright are displayed first
   197 (or rather last, the way they are printed).
   198 (ML: ProofGeneral.print_intros())
   199 
   200 * Pure: New flag trace_unify_fail causes unification to print
   201 diagnostic information (PG: in trace buffer) when it fails. This is
   202 useful for figuring out why single step proofs like rule, erule or
   203 assumption failed.
   204 
   205 * Pure: Locale specifications now produce predicate definitions
   206 according to the body of text (covering assumptions modulo local
   207 definitions); predicate "loc_axioms" covers newly introduced text,
   208 while "loc" is cumulative wrt. all included locale expressions; the
   209 latter view is presented only on export into the global theory
   210 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   211 on the old view without predicates;
   212 
   213 * Pure: predefined locales "var" and "struct" are useful for sharing
   214 parameters (as in CASL, for example); just specify something like
   215 ``var x + var y + struct M'' as import;
   216 
   217 * Pure: improved thms_containing: proper indexing of facts instead of
   218 raw theorems; check validity of results wrt. current name space;
   219 include local facts of proof configuration (also covers active
   220 locales), cover fixed variables in index; may use "_" in term
   221 specification; an optional limit for the number of printed facts may
   222 be given (the default is 40);
   223 
   224 * Pure: disallow duplicate fact bindings within new-style theory files
   225 (batch-mode only);
   226 
   227 * Provers: improved induct method: assumptions introduced by case
   228 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   229 the goal statement); "foo" still refers to all facts collectively;
   230 
   231 * Provers: the function blast.overloaded has been removed: all constants
   232 are regarded as potentially overloaded, which improves robustness in exchange
   233 for slight decrease in efficiency;
   234 
   235 * Provers/linorder: New generic prover for transitivity reasoning over
   236 linear orders.  Note: this prover is not efficient!
   237 
   238 * Isar: preview of problems to finish 'show' now produce an error
   239 rather than just a warning (in interactive mode);
   240 
   241 
   242 *** HOL ***
   243 
   244 * arith(_tac)
   245 
   246  - Produces a counter example if it cannot prove a goal.
   247    Note that the counter example may be spurious if the goal is not a formula
   248    of quantifier-free linear arithmetic.
   249    In ProofGeneral the counter example appears in the trace buffer.
   250 
   251  - Knows about div k and mod k where k is a numeral of type nat or int.
   252 
   253  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   254    linear arithmetic fails. This takes account of quantifiers and divisibility.
   255    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   256 
   257 * simp's arithmetic capabilities have been enhanced a bit: it now
   258 takes ~= in premises into account (by performing a case split);
   259 
   260 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   261 are distributed over a sum of terms;
   262 
   263 * New tactic "trans_tac" and method "trans" instantiate
   264 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   265 "<=", "<" and "="). 
   266 
   267 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   268 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   269 
   270 * 'typedef' command has new option "open" to suppress the set
   271 definition;
   272 
   273 * functions Min and Max on finite sets have been introduced (theory
   274 Finite_Set);
   275 
   276 * attribute [symmetric] now works for relations as well; it turns
   277 (x,y) : R^-1 into (y,x) : R, and vice versa;
   278 
   279 * induct over a !!-quantified statement (say !!x1..xn):
   280   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   281 
   282 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   283 %x. None. Warning: empty_def now refers to the previously hidden definition
   284 of the empty set.
   285 
   286 * Algebra: formalization of classical algebra.  Intended as base for
   287 any algebraic development in Isabelle.  Currently covers group theory
   288 (up to Sylow's theorem) and ring theory (Universal Property of
   289 Univariate Polynomials).  Contributions welcome;
   290 
   291 * GroupTheory: deleted, since its material has been moved to Algebra;
   292 
   293 * Complex: new directory of the complex numbers with numeric constants, 
   294 nonstandard complex numbers, and some complex analysis, standard and 
   295 nonstandard (Jacques Fleuriot);
   296 
   297 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   298 
   299 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   300 Fleuriot);
   301 
   302 * Real/HahnBanach: updated and adapted to locales;
   303 
   304 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   305 Gray and Kramer);
   306 
   307 * UNITY: added the Meier-Sanders theory of progress sets;
   308 
   309 * MicroJava: bytecode verifier and lightweight bytecode verifier
   310 as abstract algorithms, instantiated to the JVM;
   311 
   312 * Bali: Java source language formalization. Type system, operational
   313 semantics, axiomatic semantics. Supported language features:
   314 classes, interfaces, objects,virtual methods, static methods,
   315 static/instance fields, arrays, access modifiers, definite
   316 assignment, exceptions.
   317 
   318 
   319 *** ZF ***
   320 
   321 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   322 universe, etc.);
   323 
   324 * Main ZF: virtually all theories converted to new-style format;
   325 
   326 
   327 *** ML ***
   328 
   329 * Pure: Tactic.prove provides sane interface for internal proofs;
   330 omits the infamous "standard" operation, so this is more appropriate
   331 than prove_goalw_cterm in many situations (e.g. in simprocs);
   332 
   333 * Pure: improved error reporting of simprocs;
   334 
   335 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   336 up simprocs;
   337 
   338 
   339 *** Document preparation ***
   340 
   341 * uses \par instead of \\ for line breaks in theory text. This may
   342 shift some page breaks in large documents. To get the old behaviour
   343 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   344 
   345 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   346 other packages
   347 
   348 * \<euro> now needs package babel/greek instead of marvosym (which
   349 broke \Rightarrow)
   350 
   351 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   352 textcomp package)
   353 
   354 
   355 New in Isabelle2002 (March 2002)
   356 --------------------------------
   357 
   358 *** Document preparation ***
   359 
   360 * greatly simplified document preparation setup, including more
   361 graceful interpretation of isatool usedir -i/-d/-D options, and more
   362 instructive isatool mkdir; users should basically be able to get
   363 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   364 users may run a separate document processing stage manually like this:
   365 "isatool usedir -D output HOL Test && isatool document Test/output";
   366 
   367 * theory dependency graph may now be incorporated into documents;
   368 isatool usedir -g true will produce session_graph.eps/.pdf for use
   369 with \includegraphics of LaTeX;
   370 
   371 * proper spacing of consecutive markup elements, especially text
   372 blocks after section headings;
   373 
   374 * support bold style (for single symbols only), input syntax is like
   375 this: "\<^bold>\<alpha>" or "\<^bold>A";
   376 
   377 * \<bullet> is now output as bold \cdot by default, which looks much
   378 better in printed text;
   379 
   380 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   381 note that these symbols are currently unavailable in Proof General /
   382 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   383 
   384 * isatool latex no longer depends on changed TEXINPUTS, instead
   385 isatool document copies the Isabelle style files to the target
   386 location;
   387 
   388 
   389 *** Isar ***
   390 
   391 * Pure/Provers: improved proof by cases and induction;
   392   - 'case' command admits impromptu naming of parameters (such as
   393     "case (Suc n)");
   394   - 'induct' method divinates rule instantiation from the inductive
   395     claim; no longer requires excessive ?P bindings for proper
   396     instantiation of cases;
   397   - 'induct' method properly enumerates all possibilities of set/type
   398     rules; as a consequence facts may be also passed through *type*
   399     rules without further ado;
   400   - 'induct' method now derives symbolic cases from the *rulified*
   401     rule (before it used to rulify cases stemming from the internal
   402     atomized version); this means that the context of a non-atomic
   403     statement becomes is included in the hypothesis, avoiding the
   404     slightly cumbersome show "PROP ?case" form;
   405   - 'induct' may now use elim-style induction rules without chaining
   406     facts, using ``missing'' premises from the goal state; this allows
   407     rules stemming from inductive sets to be applied in unstructured
   408     scripts, while still benefitting from proper handling of non-atomic
   409     statements; NB: major inductive premises need to be put first, all
   410     the rest of the goal is passed through the induction;
   411   - 'induct' proper support for mutual induction involving non-atomic
   412     rule statements (uses the new concept of simultaneous goals, see
   413     below);
   414   - append all possible rule selections, but only use the first
   415     success (no backtracking);
   416   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   417   - undeclared rule case names default to numbers 1, 2, 3, ...;
   418   - added 'print_induct_rules' (covered by help item in recent Proof
   419     General versions);
   420   - moved induct/cases attributes to Pure, methods to Provers;
   421   - generic method setup instantiated for FOL and HOL;
   422 
   423 * Pure: support multiple simultaneous goal statements, for example
   424 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   425 meta-level mechanism, this acts as if several individual goals had
   426 been stated separately; in particular common proof methods need to be
   427 repeated in order to cover all claims; note that a single elimination
   428 step is *not* sufficient to establish the two conjunctions, so this
   429 fails:
   430 
   431   assume "A & B" then have A and B ..   (*".." fails*)
   432 
   433 better use "obtain" in situations as above; alternative refer to
   434 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   435 
   436 * Pure: proper integration with ``locales''; unlike the original
   437 version by Florian Kammüller, Isar locales package high-level proof
   438 contexts rather than raw logical ones (e.g. we admit to include
   439 attributes everywhere); operations on locales include merge and
   440 rename; support for implicit arguments (``structures''); simultaneous
   441 type-inference over imports and text; see also HOL/ex/Locales.thy for
   442 some examples;
   443 
   444 * Pure: the following commands have been ``localized'', supporting a
   445 target locale specification "(in name)": 'lemma', 'theorem',
   446 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   447 stored both within the locale and at the theory level (exported and
   448 qualified by the locale name);
   449 
   450 * Pure: theory goals may now be specified in ``long'' form, with
   451 ad-hoc contexts consisting of arbitrary locale elements. for example
   452 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   453 definitions may be given, too); the result is a meta-level rule with
   454 the context elements being discharged in the obvious way;
   455 
   456 * Pure: new proof command 'using' allows to augment currently used
   457 facts after a goal statement ('using' is syntactically analogous to
   458 'apply', but acts on the goal's facts only); this allows chained facts
   459 to be separated into parts given before and after a claim, as in
   460 ``from a and b have C using d and e <proof>'';
   461 
   462 * Pure: renamed "antecedent" case to "rule_context";
   463 
   464 * Pure: new 'judgment' command records explicit information about the
   465 object-logic embedding (used by several tools internally); no longer
   466 use hard-wired "Trueprop";
   467 
   468 * Pure: added 'corollary' command;
   469 
   470 * Pure: fixed 'token_translation' command;
   471 
   472 * Pure: removed obsolete 'exported' attribute;
   473 
   474 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   475 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   476 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   477 
   478 * Pure: method 'atomize' presents local goal premises as object-level
   479 statements (atomic meta-level propositions); setup controlled via
   480 rewrite rules declarations of 'atomize' attribute; example
   481 application: 'induct' method with proper rule statements in improper
   482 proof *scripts*;
   483 
   484 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   485 now consider the syntactic context of assumptions, giving a better
   486 chance to get type-inference of the arguments right (this is
   487 especially important for locales);
   488 
   489 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   490 mode;
   491 
   492 * Pure/obtain: the formal conclusion "thesis", being marked as
   493 ``internal'', may no longer be reference directly in the text;
   494 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   495 situations;
   496 
   497 * Pure: generic 'sym' attribute which declares a rule both as pure
   498 'elim?' and for the 'symmetric' operation;
   499 
   500 * Pure: marginal comments ``--'' may now occur just anywhere in the
   501 text; the fixed correlation with particular command syntax has been
   502 discontinued;
   503 
   504 * Pure: new method 'rules' is particularly well-suited for proof
   505 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   506 but often produces more compact proof terms with less detours;
   507 
   508 * Pure/Provers/classical: simplified integration with pure rule
   509 attributes and methods; the classical "intro?/elim?/dest?"
   510 declarations coincide with the pure ones; the "rule" method no longer
   511 includes classically swapped intros; "intro" and "elim" methods no
   512 longer pick rules from the context; also got rid of ML declarations
   513 AddXIs/AddXEs/AddXDs; all of this has some potential for
   514 INCOMPATIBILITY;
   515 
   516 * Provers/classical: attribute 'swapped' produces classical inversions
   517 of introduction rules;
   518 
   519 * Provers/simplifier: 'simplified' attribute may refer to explicit
   520 rules instead of full simplifier context; 'iff' attribute handles
   521 conditional rules;
   522 
   523 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   524 
   525 * HOL: 'recdef' now fails on unfinished automated proofs, use
   526 "(permissive)" option to recover old behavior;
   527 
   528 * HOL: 'inductive' no longer features separate (collective) attributes
   529 for 'intros' (was found too confusing);
   530 
   531 * HOL: properly declared induction rules less_induct and
   532 wf_induct_rule;
   533 
   534 
   535 *** HOL ***
   536 
   537 * HOL: moved over to sane numeral syntax; the new policy is as
   538 follows:
   539 
   540   - 0 and 1 are polymorphic constants, which are defined on any
   541   numeric type (nat, int, real etc.);
   542 
   543   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   544   binary representation internally;
   545 
   546   - type nat has special constructor Suc, and generally prefers Suc 0
   547   over 1::nat and Suc (Suc 0) over 2::nat;
   548 
   549 This change may cause significant problems of INCOMPATIBILITY; here
   550 are some hints on converting existing sources:
   551 
   552   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   553   entities, so expressions involving "-" (unary or binary minus) need
   554   to be spaced properly;
   555 
   556   - existing occurrences of "1" may need to be constraint "1::nat" or
   557   even replaced by Suc 0; similar for old "2";
   558 
   559   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   560 
   561   - remove all special provisions on numerals in proofs;
   562 
   563 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   564 representation (depends on bin_arith_simps in the default context);
   565 
   566 * HOL: symbolic syntax for x^2 (numeral 2);
   567 
   568 * HOL: the class of all HOL types is now called "type" rather than
   569 "term"; INCOMPATIBILITY, need to adapt references to this type class
   570 in axclass/classes, instance/arities, and (usually rare) occurrences
   571 in typings (of consts etc.); internally the class is called
   572 "HOL.type", ML programs should refer to HOLogic.typeS;
   573 
   574 * HOL/record package improvements:
   575   - new derived operations "fields" to build a partial record section,
   576     "extend" to promote a fixed record to a record scheme, and
   577     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   578     declared as simp by default;
   579   - shared operations ("more", "fields", etc.) now need to be always
   580     qualified) --- potential INCOMPATIBILITY;
   581   - removed "make_scheme" operations (use "make" with "extend") --
   582     INCOMPATIBILITY;
   583   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   584   - provides cases/induct rules for use with corresponding Isar
   585     methods (for concrete records, record schemes, concrete more
   586     parts, and schematic more parts -- in that order);
   587   - internal definitions directly based on a light-weight abstract
   588     theory of product types over typedef rather than datatype;
   589 
   590 * HOL: generic code generator for generating executable ML code from
   591 specifications; specific support for HOL constructs such as inductive
   592 datatypes and sets, as well as recursive functions; can be invoked
   593 via 'generate_code' theory section;
   594 
   595 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   596 
   597 * HOL: consolidated and renamed several theories.  In particular:
   598 	Ord.thy has been absorbed into HOL.thy
   599 	String.thy has been absorbed into List.thy
   600  
   601 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   602 (beware of argument permutation!);
   603 
   604 * HOL: linorder_less_split superseded by linorder_cases;
   605 
   606 * HOL/List: "nodups" renamed to "distinct";
   607 
   608 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   609 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   610   - Ex_def has changed, now need to use some_eq_ex
   611 
   612 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   613 in this (rare) case use:
   614 
   615   delSWrapper "split_all_tac"
   616   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   617 
   618 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   619 MAY FAIL;
   620 
   621 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   622 Isabelle's type classes, ^ on functions and relations has too general
   623 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   624 necessary to attach explicit type constraints;
   625 
   626 * HOL/Relation: the prefix name of the infix "O" has been changed from
   627 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   628 renamed accordingly (eg "compI" -> "rel_compI").
   629 
   630 * HOL: syntax translations now work properly with numerals and records
   631 expressions;
   632 
   633 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   634 of "lam" -- INCOMPATIBILITY;
   635 
   636 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   637 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   638 renamed "Product_Type.unit";
   639 
   640 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   641 
   642 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   643 the "cases" method);
   644 
   645 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   646 Florian Kammüller);
   647 
   648 * HOL/IMP: updated and converted to new-style theory format; several
   649 parts turned into readable document, with proper Isar proof texts and
   650 some explanations (by Gerwin Klein);
   651 
   652 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   653 
   654 * HOL-Hyperreal is now a logic image;
   655 
   656 
   657 *** HOLCF ***
   658 
   659 * Isar: consts/constdefs supports mixfix syntax for continuous
   660 operations;
   661 
   662 * Isar: domain package adapted to new-style theory format, e.g. see
   663 HOLCF/ex/Dnat.thy;
   664 
   665 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   666 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   667 lift.induct_tac, always use UU instead of Undef;
   668 
   669 * HOLCF/IMP: updated and converted to new-style theory;
   670 
   671 
   672 *** ZF ***
   673 
   674 * Isar: proper integration of logic-specific tools and packages,
   675 including theory commands '(co)inductive', '(co)datatype',
   676 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   677 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   678 
   679 * theory Main no longer includes AC; for the Axiom of Choice, base
   680 your theory on Main_ZFC;
   681 
   682 * the integer library now covers quotients and remainders, with many
   683 laws relating division to addition, multiplication, etc.;
   684 
   685 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   686 typeless version of the formalism;
   687 
   688 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   689 format;
   690 
   691 * ZF/Induct: new directory for examples of inductive definitions,
   692 including theory Multiset for multiset orderings; converted to
   693 new-style theory format;
   694 
   695 * ZF: many new theorems about lists, ordinals, etc.;
   696 
   697 
   698 *** General ***
   699 
   700 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   701 variable proof controls level of detail: 0 = no proofs (only oracle
   702 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   703 also ref manual for further ML interfaces;
   704 
   705 * Pure/axclass: removed obsolete ML interface
   706 goal_subclass/goal_arity;
   707 
   708 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   709 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   710 separate tokens, so expressions involving minus need to be spaced
   711 properly;
   712 
   713 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   714 rather than "infixl" or "infixr";
   715 
   716 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   717 sort constraint specifications in type inference; e.g. "x::_::foo"
   718 ensures that the type of "x" is of sort "foo" (but not necessarily a
   719 type variable);
   720 
   721 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   722 control output of nested => (types); the default behavior is
   723 "type_brackets";
   724 
   725 * Pure/syntax: builtin parse translation for "_constify" turns valued
   726 tokens into AST constants;
   727 
   728 * Pure/syntax: prefer later declarations of translations and print
   729 translation functions; potential INCOMPATIBILITY: need to reverse
   730 multiple declarations for same syntax element constant;
   731 
   732 * Pure/show_hyps reset by default (in accordance to existing Isar
   733 practice);
   734 
   735 * Provers/classical: renamed addaltern to addafter, addSaltern to
   736 addSafter;
   737 
   738 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   739 as well;
   740 
   741 * system: tested support for MacOS X; should be able to get Isabelle +
   742 Proof General to work in a plain Terminal after installing Poly/ML
   743 (e.g. from the Isabelle distribution area) and GNU bash alone
   744 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   745 support requires further installations, e.g. from
   746 http://fink.sourceforge.net/);
   747 
   748 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   749 
   750 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   751 of 40 MB), cf. ML_OPTIONS;
   752 
   753 * system: Proof General keywords specification is now part of the
   754 Isabelle distribution (see etc/isar-keywords.el);
   755 
   756 * system: support for persistent Proof General sessions (refrain from
   757 outdating all loaded theories on startup); user may create writable
   758 logic images like this: ``isabelle -q HOL Test'';
   759 
   760 * system: smart selection of Isabelle process versus Isabelle
   761 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   762 run both "isabelle" and "Isabelle" even if file names are badly
   763 damaged (executable inspects the case of the first letter of its own
   764 name); added separate "isabelle-process" and "isabelle-interface";
   765 
   766 * system: refrain from any attempt at filtering input streams; no
   767 longer support ``8bit'' encoding of old isabelle font, instead proper
   768 iso-latin characters may now be used; the related isatools
   769 "symbolinput" and "nonascii" have disappeared as well;
   770 
   771 * system: removed old "xterm" interface (the print modes "xterm" and
   772 "xterm_color" are still available for direct use in a suitable
   773 terminal);
   774 
   775 
   776 
   777 New in Isabelle99-2 (February 2001)
   778 -----------------------------------
   779 
   780 *** Overview of INCOMPATIBILITIES ***
   781 
   782 * HOL: please note that theories in the Library and elsewhere often use the
   783 new-style (Isar) format; to refer to their theorems in an ML script you must
   784 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   785 
   786 * HOL: inductive package no longer splits induction rule aggressively,
   787 but only as far as specified by the introductions given; the old
   788 format may be recovered via ML function complete_split_rule or attribute
   789 'split_rule (complete)';
   790 
   791 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   792 gfp_Tarski to gfp_unfold;
   793 
   794 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   795 
   796 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   797 relation); infix "^^" has been renamed "``"; infix "``" has been
   798 renamed "`"; "univalent" has been renamed "single_valued";
   799 
   800 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   801 operation;
   802 
   803 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   804 
   805 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   806 
   807 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   808 consequence, it is no longer monotonic wrt. the local goal context
   809 (which is now passed through the inductive cases);
   810 
   811 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   812 \<gg> to \<ggreater>;
   813 
   814 
   815 *** Document preparation ***
   816 
   817 * \isabellestyle{NAME} selects version of Isabelle output (currently
   818 available: are "it" for near math-mode best-style output, "sl" for
   819 slanted text style, and "tt" for plain type-writer; if no
   820 \isabellestyle command is given, output is according to slanted
   821 type-writer);
   822 
   823 * support sub/super scripts (for single symbols only), input syntax is
   824 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   825 
   826 * some more standard symbols; see Appendix A of the system manual for
   827 the complete list of symbols defined in isabellesym.sty;
   828 
   829 * improved isabelle style files; more abstract symbol implementation
   830 (should now use \isamath{...} and \isatext{...} in custom symbol
   831 definitions);
   832 
   833 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   834 state; Note that presentation of goal states does not conform to
   835 actual human-readable proof documents.  Please do not include goal
   836 states into document output unless you really know what you are doing!
   837 
   838 * proper indentation of antiquoted output with proportional LaTeX
   839 fonts;
   840 
   841 * no_document ML operator temporarily disables LaTeX document
   842 generation;
   843 
   844 * isatool unsymbolize tunes sources for plain ASCII communication;
   845 
   846 
   847 *** Isar ***
   848 
   849 * Pure: Isar now suffers initial goal statements to contain unbound
   850 schematic variables (this does not conform to actual readable proof
   851 documents, due to unpredictable outcome and non-compositional proof
   852 checking); users who know what they are doing may use schematic goals
   853 for Prolog-style synthesis of proven results;
   854 
   855 * Pure: assumption method (an implicit finishing) now handles actual
   856 rules as well;
   857 
   858 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   859 initial goal, declare "that" only as Pure intro (only for single
   860 steps); the "that" rule assumption may now be involved in implicit
   861 finishing, thus ".." becomes a feasible for trivial obtains;
   862 
   863 * Pure: default proof step now includes 'intro_classes'; thus trivial
   864 instance proofs may be performed by "..";
   865 
   866 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   867 statements as well;
   868 
   869 * Pure: more robust selection of calculational rules;
   870 
   871 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   872 rule (as well as the assumption rule);
   873 
   874 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   875 lemmas, using the graph browser tool;
   876 
   877 * Pure: predict failure of "show" in interactive mode;
   878 
   879 * Pure: 'thms_containing' now takes actual terms as arguments;
   880 
   881 * HOL: improved method 'induct' --- now handles non-atomic goals
   882 (potential INCOMPATIBILITY); tuned error handling;
   883 
   884 * HOL: cases and induct rules now provide explicit hints about the
   885 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   886 any remaining facts are inserted into the goal verbatim;
   887 
   888 * HOL: local contexts (aka cases) may now contain term bindings as
   889 well; the 'cases' and 'induct' methods new provide a ?case binding for
   890 the result to be shown in each case;
   891 
   892 * HOL: added 'recdef_tc' command;
   893 
   894 * isatool convert assists in eliminating legacy ML scripts;
   895 
   896 
   897 *** HOL ***
   898 
   899 * HOL/Library: a collection of generic theories to be used together
   900 with main HOL; the theory loader path already includes this directory
   901 by default; the following existing theories have been moved here:
   902 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   903 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   904 
   905 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   906 modelling and verification task performed in Isabelle/HOL +
   907 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   908 
   909 * HOL/Algebra: special summation operator SUM no longer exists, it has
   910 been replaced by setsum; infix 'assoc' now has priority 50 (like
   911 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   912 'domain', this makes the theory consistent with mathematical
   913 literature;
   914 
   915 * HOL basics: added overloaded operations "inverse" and "divide"
   916 (infix "/"), syntax for generic "abs" operation, generic summation
   917 operator \<Sum>;
   918 
   919 * HOL/typedef: simplified package, provide more useful rules (see also
   920 HOL/subset.thy);
   921 
   922 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   923 now expressed as a proper nested rule (old-style tactic scripts may
   924 require atomize_strip_tac to cope with non-atomic premises);
   925 
   926 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   927 to "split_conv" (old name still available for compatibility);
   928 
   929 * HOL: improved concrete syntax for strings (e.g. allows translation
   930 rules with string literals);
   931 
   932 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   933  and Fleuriot's mechanization of analysis, including the transcendental
   934  functions for the reals;
   935 
   936 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   937 
   938 
   939 *** CTT ***
   940 
   941 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   942 "lam" is displayed as TWO lambda-symbols
   943 
   944 * CTT: theory Main now available, containing everything (that is, Bool
   945 and Arith);
   946 
   947 
   948 *** General ***
   949 
   950 * Pure: the Simplifier has been implemented properly as a derived rule
   951 outside of the actual kernel (at last!); the overall performance
   952 penalty in practical applications is about 50%, while reliability of
   953 the Isabelle inference kernel has been greatly improved;
   954 
   955 * print modes "brackets" and "no_brackets" control output of nested =>
   956 (types) and ==> (props); the default behaviour is "brackets";
   957 
   958 * Provers: fast_tac (and friends) now handle actual object-logic rules
   959 as assumptions as well;
   960 
   961 * system: support Poly/ML 4.0;
   962 
   963 * system: isatool install handles KDE version 1 or 2;
   964 
   965 
   966 
   967 New in Isabelle99-1 (October 2000)
   968 ----------------------------------
   969 
   970 *** Overview of INCOMPATIBILITIES ***
   971 
   972 * HOL: simplification of natural numbers is much changed; to partly
   973 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   974 issue the following ML commands:
   975 
   976   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   977   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   978 
   979 * HOL: simplification no longer dives into case-expressions; this is
   980 controlled by "t.weak_case_cong" for each datatype t;
   981 
   982 * HOL: nat_less_induct renamed to less_induct;
   983 
   984 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   985 fixsome to patch .thy and .ML sources automatically;
   986 
   987   select_equality  -> some_equality
   988   select_eq_Ex     -> some_eq_ex
   989   selectI2EX       -> someI2_ex
   990   selectI2         -> someI2
   991   selectI          -> someI
   992   select1_equality -> some1_equality
   993   Eps_sym_eq       -> some_sym_eq_trivial
   994   Eps_eq           -> some_eq_trivial
   995 
   996 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   997 
   998 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   999 instead);
  1000 
  1001 * HOL: the recursion equations generated by 'recdef' are now called
  1002 f.simps instead of f.rules;
  1003 
  1004 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1005 
  1006 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1007 sometimes be needed;
  1008 
  1009 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1010 
  1011 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1012 
  1013 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1014 product is now "<*>" instead of "Times"; the lexicographic product is
  1015 now "<*lex*>" instead of "**";
  1016 
  1017 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1018 of main HOL, but was unused); better use HOL's datatype package;
  1019 
  1020 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1021 the old syntax may be recovered as follows:
  1022 
  1023   syntax (symbols)
  1024     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1025       (infixl "\\<oplus>" 100)
  1026 
  1027 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1028 
  1029 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1030 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1031 internally;
  1032 
  1033 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1034 changed from A/r to A//r;
  1035 
  1036 * ZF: new treatment of arithmetic (nat & int) may break some old
  1037 proofs;
  1038 
  1039 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1040 rulify -> rule_format, elimify -> elim_format, ...);
  1041 
  1042 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1043 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1044 should have to change intro!! to intro? only); replaced "delrule" by
  1045 "rule del";
  1046 
  1047 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1048 
  1049 * Provers: strengthened force_tac by using new first_best_tac;
  1050 
  1051 * LaTeX document preparation: several changes of isabelle.sty (see
  1052 lib/texinputs);
  1053 
  1054 
  1055 *** Document preparation ***
  1056 
  1057 * formal comments (text blocks etc.) in new-style theories may now
  1058 contain antiquotations of thm/prop/term/typ/text to be presented
  1059 according to latex print mode; concrete syntax is like this:
  1060 @{term[show_types] "f(x) = a + x"};
  1061 
  1062 * isatool mkdir provides easy setup of Isabelle session directories,
  1063 including proper document sources;
  1064 
  1065 * generated LaTeX sources are now deleted after successful run
  1066 (isatool document -c); may retain a copy somewhere else via -D option
  1067 of isatool usedir;
  1068 
  1069 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1070 style files, achieving self-contained LaTeX sources and simplifying
  1071 LaTeX debugging;
  1072 
  1073 * old-style theories now produce (crude) LaTeX output as well;
  1074 
  1075 * browser info session directories are now self-contained (may be put
  1076 on WWW server seperately); improved graphs of nested sessions; removed
  1077 graph for 'all sessions';
  1078 
  1079 * several improvements in isabelle style files; \isabellestyle{it}
  1080 produces fake math mode output; \isamarkupheader is now \section by
  1081 default; see lib/texinputs/isabelle.sty etc.;
  1082 
  1083 
  1084 *** Isar ***
  1085 
  1086 * Isar/Pure: local results and corresponding term bindings are now
  1087 subject to Hindley-Milner polymorphism (similar to ML); this
  1088 accommodates incremental type-inference very nicely;
  1089 
  1090 * Isar/Pure: new derived language element 'obtain' supports
  1091 generalized existence reasoning;
  1092 
  1093 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1094 support accumulation of results, without applying any rules yet;
  1095 useful to collect intermediate results without explicit name
  1096 references, and for use with transitivity rules with more than 2
  1097 premises;
  1098 
  1099 * Isar/Pure: scalable support for case-analysis type proofs: new
  1100 'case' language element refers to local contexts symbolically, as
  1101 produced by certain proof methods; internally, case names are attached
  1102 to theorems as "tags";
  1103 
  1104 * Isar/Pure: theory command 'hide' removes declarations from
  1105 class/type/const name spaces;
  1106 
  1107 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1108 indicate potential overloading;
  1109 
  1110 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1111 
  1112 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1113 "{a,b,c}" instead of {a,b,c};
  1114 
  1115 * Isar/Pure now provides its own version of intro/elim/dest
  1116 attributes; useful for building new logics, but beware of confusion
  1117 with the version in Provers/classical;
  1118 
  1119 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1120 case name 'antecedent';
  1121 
  1122 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1123 to the current context is now done automatically);
  1124 
  1125 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1126 for definining proof methods in ML;
  1127 
  1128 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1129 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1130 most cases, one should have to change intro!! to intro? only);
  1131 replaced "delrule" by "rule del";
  1132 
  1133 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1134 'symmetric' attribute (the latter supercedes [RS sym]);
  1135 
  1136 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1137 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1138 well (including splits);
  1139 
  1140 * Isar/Provers: Simplifier and Classical methods now support all kind
  1141 of modifiers used in the past, including 'cong', 'iff', etc.
  1142 
  1143 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1144 of Simplifier and Classical reasoner);
  1145 
  1146 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1147 now support named cases; major packages (inductive, datatype, primrec,
  1148 recdef) support case names and properly name parameters;
  1149 
  1150 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1151 monotonicity conditions are extracted to be proven at end of
  1152 calculations;
  1153 
  1154 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1155 method anyway;
  1156 
  1157 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1158 split_if split_if_asm; datatype package provides theorems foo.splits =
  1159 foo.split foo.split_asm for each datatype;
  1160 
  1161 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1162 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1163 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1164 use "(cases (simplified))" method in proper proof texts);
  1165 
  1166 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1167 
  1168 * Isar: names of theorems etc. may be natural numbers as well;
  1169 
  1170 * Isar: 'pr' command: optional arguments for goals_limit and
  1171 ProofContext.prems_limit; no longer prints theory contexts, but only
  1172 proof states;
  1173 
  1174 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1175 additional print modes to be specified; e.g. "pr(latex)" will print
  1176 proof state according to the Isabelle LaTeX style;
  1177 
  1178 * Isar: improved support for emulating tactic scripts, including proof
  1179 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1180 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1181 (for HOL datatypes);
  1182 
  1183 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1184 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1185 'proof method scripts' have to be in depth-first order;
  1186 
  1187 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1188 
  1189 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1190 should instead use individual commands for printing items
  1191 (print_commands, print_methods etc.);
  1192 
  1193 * Isar: added 'nothing' --- the empty list of theorems;
  1194 
  1195 
  1196 *** HOL ***
  1197 
  1198 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1199 corresponding virtual machine and a specification of its bytecode
  1200 verifier and a lightweight bytecode verifier, including proofs of
  1201 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1202 Cornelia Pusch (see also the homepage of project Bali at
  1203 http://isabelle.in.tum.de/Bali/);
  1204 
  1205 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1206 Clemens Ballarin;
  1207 
  1208 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1209 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1210 Rasmussen;
  1211 
  1212 * HOL/Lattice: fundamental concepts of lattice theory and order
  1213 structures, including duals, properties of bounds versus algebraic
  1214 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1215 Theorem for complete lattices etc.; may also serve as a demonstration
  1216 for abstract algebraic reasoning using axiomatic type classes, and
  1217 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1218 
  1219 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1220 von Oheimb;
  1221 
  1222 * HOL/IMPP: extension of IMP with local variables and mutually
  1223 recursive procedures, by David von Oheimb;
  1224 
  1225 * HOL/Lambda: converted into new-style theory and document;
  1226 
  1227 * HOL/ex/Multiquote: example of multiple nested quotations and
  1228 anti-quotations -- basically a generalized version of de-Bruijn
  1229 representation; very useful in avoiding lifting of operations;
  1230 
  1231 * HOL/record: added general record equality rule to simpset; fixed
  1232 select-update simplification procedure to handle extended records as
  1233 well; admit "r" as field name;
  1234 
  1235 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1236 other numeric types and also as the identity of groups, rings, etc.;
  1237 
  1238 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1239 Types nat and int belong to this axclass;
  1240 
  1241 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1242    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1243    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1244   two terms #m*u and #n*u are replaced by #(m+n)*u
  1245     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1246   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1247     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1248 
  1249 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1250 powerful prover for predicate logic but knows nothing of clasets; see
  1251 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1252 
  1253 * HOL: new version of "case_tac" subsumes both boolean case split and
  1254 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1255 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1256 
  1257 * HOL: simplification no longer dives into case-expressions: only the
  1258 selector expression is simplified, but not the remaining arms; to
  1259 enable full simplification of case-expressions for datatype t, you may
  1260 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1261 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1262 
  1263 * HOL/recdef: the recursion equations generated by 'recdef' for
  1264 function 'f' are now called f.simps instead of f.rules; if all
  1265 termination conditions are proved automatically, these simplification
  1266 rules are added to the simpset, as in primrec; rules may be named
  1267 individually as well, resulting in a separate list of theorems for
  1268 each equation;
  1269 
  1270 * HOL/While is a new theory that provides a while-combinator. It
  1271 permits the definition of tail-recursive functions without the
  1272 provision of a termination measure. The latter is necessary once the
  1273 invariant proof rule for while is applied.
  1274 
  1275 * HOL: new (overloaded) notation for the set of elements below/above
  1276 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1277 
  1278 * HOL: theorems impI, allI, ballI bound as "strip";
  1279 
  1280 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1281 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1282 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1283 
  1284 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1285 
  1286 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1287 main HOL, but was unused);
  1288 
  1289 * HOL: fewer consts declared as global (e.g. have to refer to
  1290 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1291 
  1292 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1293 in case of overlap with user translations (e.g. judgements over
  1294 tuples); (note that the underlying logical represenation is still
  1295 bogus);
  1296 
  1297 
  1298 *** ZF ***
  1299 
  1300 * ZF: simplification automatically cancels common terms in arithmetic
  1301 expressions over nat and int;
  1302 
  1303 * ZF: new treatment of nat to minimize type-checking: all operators
  1304 coerce their operands to a natural number using the function natify,
  1305 making the algebraic laws unconditional;
  1306 
  1307 * ZF: as above, for int: operators coerce their operands to an integer
  1308 using the function intify;
  1309 
  1310 * ZF: the integer library now contains many of the usual laws for the
  1311 orderings, including $<=, and monotonicity laws for $+ and $*;
  1312 
  1313 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1314 simplification;
  1315 
  1316 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1317 to the simplifier and classical reasoner simultaneously;
  1318 
  1319 
  1320 *** General ***
  1321 
  1322 * Provers: blast_tac now handles actual object-logic rules as
  1323 assumptions; note that auto_tac uses blast_tac internally as well;
  1324 
  1325 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1326 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1327 
  1328 * Provers: delrules now handles destruct rules as well (no longer need
  1329 explicit make_elim);
  1330 
  1331 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1332   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1333 use instead the strong form,
  1334   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1335 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1336 from destruct-rules;
  1337 
  1338 * Provers: Simplifier.easy_setup provides a fast path to basic
  1339 Simplifier setup for new object-logics;
  1340 
  1341 * Pure: AST translation rules no longer require constant head on LHS;
  1342 
  1343 * Pure: improved name spaces: ambiguous output is qualified; support
  1344 for hiding of names;
  1345 
  1346 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1347 XSYMBOL_HOME; no longer need to do manual configuration in most
  1348 situations;
  1349 
  1350 * system: compression of ML heaps images may now be controlled via -c
  1351 option of isabelle and isatool usedir (currently only observed by
  1352 Poly/ML);
  1353 
  1354 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1355 useful for remote X11);
  1356 
  1357 * system: provide TAGS file for Isabelle sources;
  1358 
  1359 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1360 order;
  1361 
  1362 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1363 timing flag supersedes proof_timing and Toplevel.trace;
  1364 
  1365 * ML: new combinators |>> and |>>> for incremental transformations
  1366 with secondary results (e.g. certain theory extensions):
  1367 
  1368 * ML: PureThy.add_defs gets additional argument to indicate potential
  1369 overloading (usually false);
  1370 
  1371 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1372 results;
  1373 
  1374 
  1375 
  1376 New in Isabelle99 (October 1999)
  1377 --------------------------------
  1378 
  1379 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1380 
  1381 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1382 are no longer simplified.  (This allows the simplifier to unfold recursive
  1383 functional programs.)  To restore the old behaviour, declare
  1384 
  1385     Delcongs [if_weak_cong];
  1386 
  1387 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1388 complement;
  1389 
  1390 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1391 
  1392 * HOL/datatype: mutual_induct_tac no longer exists --
  1393   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1394 
  1395 * HOL/typedef: fixed type inference for representing set; type
  1396 arguments now have to occur explicitly on the rhs as type constraints;
  1397 
  1398 * ZF: The con_defs part of an inductive definition may no longer refer
  1399 to constants declared in the same theory;
  1400 
  1401 * HOL, ZF: the function mk_cases, generated by the inductive
  1402 definition package, has lost an argument.  To simplify its result, it
  1403 uses the default simpset instead of a supplied list of theorems.
  1404 
  1405 * HOL/List: the constructors of type list are now Nil and Cons;
  1406 
  1407 * Simplifier: the type of the infix ML functions
  1408         setSSolver addSSolver setSolver addSolver
  1409 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1410 for packaging solvers. A solver is created via
  1411         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1412 where the string argument is only a comment.
  1413 
  1414 
  1415 *** Proof tools ***
  1416 
  1417 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1418 decision procedure for linear arithmetic. Currently it is used for
  1419 types `nat', `int', and `real' in HOL (see below); it can, should and
  1420 will be instantiated for other types and logics as well.
  1421 
  1422 * The simplifier now accepts rewrite rules with flexible heads, eg
  1423      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1424   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1425   matching.
  1426 
  1427 
  1428 *** General ***
  1429 
  1430 * New Isabelle/Isar subsystem provides an alternative to traditional
  1431 tactical theorem proving; together with the ProofGeneral/isar user
  1432 interface it offers an interactive environment for developing human
  1433 readable proof documents (Isar == Intelligible semi-automated
  1434 reasoning); for further information see isatool doc isar-ref,
  1435 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1436 
  1437 * improved and simplified presentation of theories: better HTML markup
  1438 (including colors), graph views in several sizes; isatool usedir now
  1439 provides a proper interface for user theories (via -P option); actual
  1440 document preparation based on (PDF)LaTeX is available as well (for
  1441 new-style theories only); see isatool doc system for more information;
  1442 
  1443 * native support for Proof General, both for classic Isabelle and
  1444 Isabelle/Isar;
  1445 
  1446 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1447 using the graph browser tool;
  1448 
  1449 * Isabelle manuals now also available as PDF;
  1450 
  1451 * theory loader rewritten from scratch (may not be fully
  1452 bug-compatible); old loadpath variable has been replaced by show_path,
  1453 add_path, del_path, reset_path functions; new operations such as
  1454 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1455 isatool doc ref);
  1456 
  1457 * improved isatool install: option -k creates KDE application icon,
  1458 option -p DIR installs standalone binaries;
  1459 
  1460 * added ML_PLATFORM setting (useful for cross-platform installations);
  1461 more robust handling of platform specific ML images for SML/NJ;
  1462 
  1463 * the settings environment is now statically scoped, i.e. it is never
  1464 created again in sub-processes invoked from isabelle, isatool, or
  1465 Isabelle;
  1466 
  1467 * path element specification '~~' refers to '$ISABELLE_HOME';
  1468 
  1469 * in locales, the "assumes" and "defines" parts may be omitted if
  1470 empty;
  1471 
  1472 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1473 long arrows);
  1474 
  1475 * new print_mode "HTML";
  1476 
  1477 * new flag show_tags controls display of tags of theorems (which are
  1478 basically just comments that may be attached by some tools);
  1479 
  1480 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1481 mode and goal output format:
  1482 
  1483 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1484 244c244
  1485 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1486 ---
  1487 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1488 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1489 181c181
  1490 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1491 ---
  1492 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1493 
  1494 * function bind_thms stores lists of theorems (cf. bind_thm);
  1495 
  1496 * new shorthand tactics ftac, eatac, datac, fatac;
  1497 
  1498 * qed (and friends) now accept "" as result name; in that case the
  1499 theorem is not stored, but proper checks and presentation of the
  1500 result still apply;
  1501 
  1502 * theorem database now also indexes constants "Trueprop", "all",
  1503 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1504 
  1505 
  1506 *** HOL ***
  1507 
  1508 ** HOL arithmetic **
  1509 
  1510 * There are now decision procedures for linear arithmetic over nat and
  1511 int:
  1512 
  1513 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1514 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1515 are treated as atomic; subformulae not involving type `nat' or `int'
  1516 are ignored; quantified subformulae are ignored unless they are
  1517 positive universal or negative existential. The tactic has to be
  1518 invoked by hand and can be a little bit slow. In particular, the
  1519 running time is exponential in the number of occurrences of `min' and
  1520 `max', and `-' on `nat'.
  1521 
  1522 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1523 (negated) (in)equalities among the premises and the conclusion into
  1524 account (i.e. no compound formulae) and does not know about `min' and
  1525 `max', and `-' on `nat'. It is fast and is used automatically by the
  1526 simplifier.
  1527 
  1528 NB: At the moment, these decision procedures do not cope with mixed
  1529 nat/int formulae where the two parts interact, such as `m < n ==>
  1530 int(m) < int(n)'.
  1531 
  1532 * HOL/Numeral provides a generic theory of numerals (encoded
  1533 efficiently as bit strings); setup for types nat/int/real is in place;
  1534 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1535 int, existing theories and proof scripts may require a few additional
  1536 type constraints;
  1537 
  1538 * integer division and remainder can now be performed on constant
  1539 arguments;
  1540 
  1541 * many properties of integer multiplication, division and remainder
  1542 are now available;
  1543 
  1544 * An interface to the Stanford Validity Checker (SVC) is available through the
  1545 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1546 are proved automatically.  SVC must be installed separately, and its results
  1547 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1548 invocation of the underlying oracle).  For SVC see
  1549   http://verify.stanford.edu/SVC
  1550 
  1551 * IsaMakefile: the HOL-Real target now builds an actual image;
  1552 
  1553 
  1554 ** HOL misc **
  1555 
  1556 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1557 (in Isabelle/Isar) -- by Gertrud Bauer;
  1558 
  1559 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1560 analysis for assembly languages with subtypes;
  1561 
  1562 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1563 -- avoids syntactic ambiguities and treats state, transition, and
  1564 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1565 changed syntax and (many) tactics;
  1566 
  1567 * HOL/inductive: Now also handles more general introduction rules such
  1568   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1569   theorems are now maintained within the theory (maintained via the
  1570   "mono" attribute);
  1571 
  1572 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1573   (using function types) such as
  1574 
  1575   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1576 
  1577 * HOL/record: record_simproc (part of the default simpset) takes care
  1578 of selectors applied to updated records; record_split_tac is no longer
  1579 part of the default claset; update_defs may now be removed from the
  1580 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1581 
  1582   claset_ref () := claset() addSWrapper record_split_wrapper;
  1583   Delsimprocs [record_simproc]
  1584 
  1585 * HOL/typedef: fixed type inference for representing set; type
  1586 arguments now have to occur explicitly on the rhs as type constraints;
  1587 
  1588 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1589 names rather than an ML expression;
  1590 
  1591 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1592 supplied later.  Program schemes can be defined, such as
  1593     "While B C s = (if B s then While B C (C s) else s)"
  1594 where the well-founded relation can be chosen after B and C have been given.
  1595 
  1596 * HOL/List: the constructors of type list are now Nil and Cons;
  1597 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1598 course, ML tools referring to List.list.op # etc. have to be adapted;
  1599 
  1600 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1601 disabled by default; run isabelle with option -m HOL to get back to
  1602 the original Gordon/HOL-style output;
  1603 
  1604 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1605 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1606 
  1607 * HOL basic syntax simplified (more orthogonal): all variants of
  1608 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1609 Eps operator is provided as well: "SOME x. P[x]";
  1610 
  1611 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1612 
  1613 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1614 thus available for user theories;
  1615 
  1616 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1617 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1618 time;
  1619 
  1620 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1621 several times and then mp;
  1622 
  1623 
  1624 *** LK ***
  1625 
  1626 * the notation <<...>> is now available as a notation for sequences of
  1627 formulas;
  1628 
  1629 * the simplifier is now installed
  1630 
  1631 * the axiom system has been generalized (thanks to Soren Heilmann)
  1632 
  1633 * the classical reasoner now has a default rule database
  1634 
  1635 
  1636 *** ZF ***
  1637 
  1638 * new primrec section allows primitive recursive functions to be given
  1639 directly (as in HOL) over datatypes and the natural numbers;
  1640 
  1641 * new tactics induct_tac and exhaust_tac for induction (or case
  1642 analysis) over datatypes and the natural numbers;
  1643 
  1644 * the datatype declaration of type T now defines the recursor T_rec;
  1645 
  1646 * simplification automatically does freeness reasoning for datatype
  1647 constructors;
  1648 
  1649 * automatic type-inference, with AddTCs command to insert new
  1650 type-checking rules;
  1651 
  1652 * datatype introduction rules are now added as Safe Introduction rules
  1653 to the claset;
  1654 
  1655 * the syntax "if P then x else y" is now available in addition to
  1656 if(P,x,y);
  1657 
  1658 
  1659 *** Internal programming interfaces ***
  1660 
  1661 * tuned simplifier trace output; new flag debug_simp;
  1662 
  1663 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1664 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1665 
  1666 * AxClass.axclass_tac lost the theory argument;
  1667 
  1668 * tuned current_goals_markers semantics: begin / end goal avoids
  1669 printing empty lines;
  1670 
  1671 * removed prs and prs_fn hook, which was broken because it did not
  1672 include \n in its semantics, forcing writeln to add one
  1673 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1674 string -> unit if you really want to output text without newline;
  1675 
  1676 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1677 plain output, interface builders may have to enable 'isabelle_font'
  1678 mode to get Isabelle font glyphs as before;
  1679 
  1680 * refined token_translation interface; INCOMPATIBILITY: output length
  1681 now of type real instead of int;
  1682 
  1683 * theory loader actions may be traced via new ThyInfo.add_hook
  1684 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1685 your own database of information attached to *whole* theories -- as
  1686 opposed to intra-theory data slots offered via TheoryDataFun;
  1687 
  1688 * proper handling of dangling sort hypotheses (at last!);
  1689 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1690 extra sort hypotheses that can be witnessed from the type signature;
  1691 the force_strip_shyps flag is gone, any remaining shyps are simply
  1692 left in the theorem (with a warning issued by strip_shyps_warning);
  1693 
  1694 
  1695 
  1696 New in Isabelle98-1 (October 1998)
  1697 ----------------------------------
  1698 
  1699 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1700 
  1701 * several changes of automated proof tools;
  1702 
  1703 * HOL: major changes to the inductive and datatype packages, including
  1704 some minor incompatibilities of theory syntax;
  1705 
  1706 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1707 called `inj_on';
  1708 
  1709 * HOL: removed duplicate thms in Arith:
  1710   less_imp_add_less  should be replaced by  trans_less_add1
  1711   le_imp_add_le      should be replaced by  trans_le_add1
  1712 
  1713 * HOL: unary minus is now overloaded (new type constraints may be
  1714 required);
  1715 
  1716 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1717 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1718 now taken as an integer constant.
  1719 
  1720 * Pure: ML function 'theory_of' renamed to 'theory';
  1721 
  1722 
  1723 *** Proof tools ***
  1724 
  1725 * Simplifier:
  1726   1. Asm_full_simp_tac is now more aggressive.
  1727      1. It will sometimes reorient premises if that increases their power to
  1728         simplify.
  1729      2. It does no longer proceed strictly from left to right but may also
  1730         rotate premises to achieve further simplification.
  1731      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1732      old Asm_full_simp_tac in that it does not rotate premises.
  1733   2. The simplifier now knows a little bit about nat-arithmetic.
  1734 
  1735 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1736 allows for selected deletion of wrappers, by introduction of names for
  1737 wrapper functionals.  This implies that addbefore, addSbefore,
  1738 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1739 and that adding two tactics with the same name overwrites the first
  1740 one (emitting a warning).
  1741   type wrapper = (int -> tactic) -> (int -> tactic)
  1742   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1743   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1744   delWrapper, delSWrapper: claset *  string            -> claset
  1745   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1746 
  1747 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1748 semantics; addbefore now affects only the unsafe part of step_tac
  1749 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1750 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1751 by Force_tac;
  1752 
  1753 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1754 compWrapper; added safe wrapper (and access functions for it);
  1755 
  1756 * HOL/split_all_tac is now much faster and fails if there is nothing
  1757 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1758 and the names of the automatically generated variables have changed.
  1759 split_all_tac has moved within claset() from unsafe wrappers to safe
  1760 wrappers, which means that !!-bound variables are split much more
  1761 aggressively, and safe_tac and clarify_tac now split such variables.
  1762 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1763 Note: the same holds for record_split_tac, which does the job of
  1764 split_all_tac for record fields.
  1765 
  1766 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1767 permanently to the default simpset using Addsplits just like
  1768 Addsimps. They can be removed via Delsplits just like
  1769 Delsimps. Lower-case versions are also available.
  1770 
  1771 * HOL/Simplifier: The rule split_if is now part of the default
  1772 simpset. This means that the simplifier will eliminate all occurrences
  1773 of if-then-else in the conclusion of a goal. To prevent this, you can
  1774 either remove split_if completely from the default simpset by
  1775 `Delsplits [split_if]' or remove it in a specific call of the
  1776 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1777 other case splitting rules to/from the default simpset: every datatype
  1778 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1779 t is the name of the datatype).
  1780 
  1781 * Classical reasoner / Simplifier combination: new force_tac (and
  1782 derivatives Force_tac, force) combines rewriting and classical
  1783 reasoning (and whatever other tools) similarly to auto_tac, but is
  1784 aimed to solve the given subgoal completely.
  1785 
  1786 
  1787 *** General ***
  1788 
  1789 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1790 and `goalw': the theory is no longer needed as an explicit argument -
  1791 the current theory context is used; assumptions are no longer returned
  1792 at the ML-level unless one of them starts with ==> or !!; it is
  1793 recommended to convert to these new commands using isatool fixgoal
  1794 (backup your sources first!);
  1795 
  1796 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1797 the current theory context, and 'theory' to lookup stored theories;
  1798 
  1799 * new theory section 'locale' for declaring constants, assumptions and
  1800 definitions that have local scope;
  1801 
  1802 * new theory section 'nonterminals' for purely syntactic types;
  1803 
  1804 * new theory section 'setup' for generic ML setup functions
  1805 (e.g. package initialization);
  1806 
  1807 * the distribution now includes Isabelle icons: see
  1808 lib/logo/isabelle-{small,tiny}.xpm;
  1809 
  1810 * isatool install - install binaries with absolute references to
  1811 ISABELLE_HOME/bin;
  1812 
  1813 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1814 
  1815 * print mode 'emacs' reserved for Isamode;
  1816 
  1817 * support multiple print (ast) translations per constant name;
  1818 
  1819 * theorems involving oracles are now printed with a suffixed [!];
  1820 
  1821 
  1822 *** HOL ***
  1823 
  1824 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1825 
  1826 * HOL/inductive package reorganized and improved: now supports mutual
  1827 definitions such as
  1828 
  1829   inductive EVEN ODD
  1830     intrs
  1831       null "0 : EVEN"
  1832       oddI "n : EVEN ==> Suc n : ODD"
  1833       evenI "n : ODD ==> Suc n : EVEN"
  1834 
  1835 new theorem list "elims" contains an elimination rule for each of the
  1836 recursive sets; inductive definitions now handle disjunctive premises
  1837 correctly (also ZF);
  1838 
  1839 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1840 "mutual_induct" no longer exists - the induction rule is always
  1841 contained in "induct";
  1842 
  1843 
  1844 * HOL/datatype package re-implemented and greatly improved: now
  1845 supports mutually recursive datatypes such as
  1846 
  1847   datatype
  1848     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1849             | SUM ('a aexp) ('a aexp)
  1850             | DIFF ('a aexp) ('a aexp)
  1851             | NUM 'a
  1852   and
  1853     'a bexp = LESS ('a aexp) ('a aexp)
  1854             | AND ('a bexp) ('a bexp)
  1855             | OR ('a bexp) ('a bexp)
  1856 
  1857 as well as indirectly recursive datatypes such as
  1858 
  1859   datatype
  1860     ('a, 'b) term = Var 'a
  1861                   | App 'b ((('a, 'b) term) list)
  1862 
  1863 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1864 induction on mutually / indirectly recursive datatypes.
  1865 
  1866 Primrec equations are now stored in theory and can be accessed via
  1867 <function_name>.simps.
  1868 
  1869 INCOMPATIBILITIES:
  1870 
  1871   - Theories using datatypes must now have theory Datatype as an
  1872     ancestor.
  1873   - The specific <typename>.induct_tac no longer exists - use the
  1874     generic induct_tac instead.
  1875   - natE has been renamed to nat.exhaust - use exhaust_tac
  1876     instead of res_inst_tac ... natE. Note that the variable
  1877     names in nat.exhaust differ from the names in natE, this
  1878     may cause some "fragile" proofs to fail.
  1879   - The theorems split_<typename>_case and split_<typename>_case_asm
  1880     have been renamed to <typename>.split and <typename>.split_asm.
  1881   - Since default sorts of type variables are now handled correctly,
  1882     some datatype definitions may have to be annotated with explicit
  1883     sort constraints.
  1884   - Primrec definitions no longer require function name and type
  1885     of recursive argument.
  1886 
  1887 Consider using isatool fixdatatype to adapt your theories and proof
  1888 scripts to the new package (backup your sources first!).
  1889 
  1890 
  1891 * HOL/record package: considerably improved implementation; now
  1892 includes concrete syntax for record types, terms, updates; theorems
  1893 for surjective pairing and splitting !!-bound record variables; proof
  1894 support is as follows:
  1895 
  1896   1) standard conversions (selectors or updates applied to record
  1897 constructor terms) are part of the standard simpset;
  1898 
  1899   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1900 made part of standard simpset and claset via addIffs;
  1901 
  1902   3) a tactic for record field splitting (record_split_tac) is part of
  1903 the standard claset (addSWrapper);
  1904 
  1905 To get a better idea about these rules you may retrieve them via
  1906 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1907 the name of your record type.
  1908 
  1909 The split tactic 3) conceptually simplifies by the following rule:
  1910 
  1911   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1912 
  1913 Thus any record variable that is bound by meta-all will automatically
  1914 blow up into some record constructor term, consequently the
  1915 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1916 solve record problems automatically.
  1917 
  1918 
  1919 * reorganized the main HOL image: HOL/Integ and String loaded by
  1920 default; theory Main includes everything;
  1921 
  1922 * automatic simplification of integer sums and comparisons, using cancellation;
  1923 
  1924 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1925 
  1926 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1927 
  1928 * many new identities for unions, intersections, set difference, etc.;
  1929 
  1930 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1931 called split_if, split_split, split_sum_case and split_nat_case (to go
  1932 with add/delsplits);
  1933 
  1934 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1935 (?x::unit) = (); this is made part of the default simpset, which COULD
  1936 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1937 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1938 unit_abs_eta_conv is added in order to counter the effect of
  1939 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1940 %u.f();
  1941 
  1942 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1943 makes more sense);
  1944 
  1945 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1946   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1947   disjointness reasoning but breaking a few old proofs.
  1948 
  1949 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1950 to 'converse' from 'inverse' (for compatibility with ZF and some
  1951 literature);
  1952 
  1953 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1954 the well-founded relation;
  1955 
  1956 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1957     Compl A.  The "Compl" syntax remains available as input syntax for this
  1958     release ONLY.
  1959 
  1960 * HOL/Update: new theory of function updates:
  1961     f(a:=b) == %x. if x=a then b else f x
  1962 may also be iterated as in f(a:=b,c:=d,...);
  1963 
  1964 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1965 
  1966 * HOL/List:
  1967   - new function list_update written xs[i:=v] that updates the i-th
  1968     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1969   - new function `upt' written [i..j(] which generates the list
  1970     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1971     bound write [i..j], which is a shorthand for [i..j+1(].
  1972   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1973 
  1974 * HOL/Arith:
  1975   - removed 'pred' (predecessor) function;
  1976   - generalized some theorems about n-1;
  1977   - many new laws about "div" and "mod";
  1978   - new laws about greatest common divisors (see theory ex/Primes);
  1979 
  1980 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1981 instead of "inverse";
  1982 
  1983 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1984   of the multiset ordering;
  1985 
  1986 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1987   (not included by default);
  1988 
  1989 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1990 
  1991 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1992   programs, i.e. different program variables may have different types.
  1993 
  1994 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1995   [previously, this check worked only if the rewrite rule was unconditional]
  1996   Now rew can involve either definitions or equalities (either == or =).
  1997 
  1998 
  1999 *** ZF ***
  2000 
  2001 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2002   only the theorems proved on ZF.ML;
  2003 
  2004 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2005   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2006   disjointness reasoning but breaking a few old proofs.
  2007 
  2008 * ZF/Update: new theory of function updates
  2009     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2010   may also be iterated as in f(a:=b,c:=d,...);
  2011 
  2012 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2013 
  2014 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2015   [previously, this check worked only if the rewrite rule was unconditional]
  2016   Now rew can involve either definitions or equalities (either == or =).
  2017 
  2018 * case_tac provided for compatibility with HOL
  2019     (like the old excluded_middle_tac, but with subgoals swapped)
  2020 
  2021 
  2022 *** Internal programming interfaces ***
  2023 
  2024 * Pure: several new basic modules made available for general use, see
  2025 also src/Pure/README;
  2026 
  2027 * improved the theory data mechanism to support encapsulation (data
  2028 kind name replaced by private Object.kind, acting as authorization
  2029 key); new type-safe user interface via functor TheoryDataFun; generic
  2030 print_data function becomes basically useless;
  2031 
  2032 * removed global_names compatibility flag -- all theory declarations
  2033 are qualified by default;
  2034 
  2035 * module Pure/Syntax now offers quote / antiquote translation
  2036 functions (useful for Hoare logic etc. with implicit dependencies);
  2037 see HOL/ex/Antiquote for an example use;
  2038 
  2039 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2040 cterm -> thm;
  2041 
  2042 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2043 subgoal;
  2044 
  2045 * Display.print_goals function moved to Locale.print_goals;
  2046 
  2047 * standard print function for goals supports current_goals_markers
  2048 variable for marking begin of proof, end of proof, start of goal; the
  2049 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2050 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2051 for example;
  2052 
  2053 
  2054 
  2055 New in Isabelle98 (January 1998)
  2056 --------------------------------
  2057 
  2058 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2059 
  2060 * changed lexical syntax of terms / types: dots made part of long
  2061 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2062 
  2063 * simpset (and claset) reference variable replaced by functions
  2064 simpset / simpset_ref;
  2065 
  2066 * no longer supports theory aliases (via merge) and non-trivial
  2067 implicit merge of thms' signatures;
  2068 
  2069 * most internal names of constants changed due to qualified names;
  2070 
  2071 * changed Pure/Sequence interface (see Pure/seq.ML);
  2072 
  2073 
  2074 *** General Changes ***
  2075 
  2076 * hierachically structured name spaces (for consts, types, axms, thms
  2077 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2078 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2079 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2080 long_names for fully qualified output names; NOTE: ML programs
  2081 (special tactics, packages etc.) referring to internal names may have
  2082 to be adapted to cope with fully qualified names; in case of severe
  2083 backward campatibility problems try setting 'global_names' at compile
  2084 time to have enrything declared within a flat name space; one may also
  2085 fine tune name declarations in theories via the 'global' and 'local'
  2086 section;
  2087 
  2088 * reimplemented the implicit simpset and claset using the new anytype
  2089 data filed in signatures; references simpset:simpset ref etc. are
  2090 replaced by functions simpset:unit->simpset and
  2091 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2092 to patch your ML files accordingly;
  2093 
  2094 * HTML output now includes theory graph data for display with Java
  2095 applet or isatool browser; data generated automatically via isatool
  2096 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2097 
  2098 * defs may now be conditional; improved rewrite_goals_tac to handle
  2099 conditional equations;
  2100 
  2101 * defs now admits additional type arguments, using TYPE('a) syntax;
  2102 
  2103 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2104 creates a new theory node; implicit merge of thms' signatures is
  2105 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2106 transfer:theory->thm->thm in (rare) cases;
  2107 
  2108 * improved handling of draft signatures / theories; draft thms (and
  2109 ctyps, cterms) are automatically promoted to real ones;
  2110 
  2111 * slightly changed interfaces for oracles: admit many per theory, named
  2112 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2113 
  2114 * print_goals: optional output of const types (set show_consts and
  2115 show_types);
  2116 
  2117 * improved output of warnings (###) and errors (***);
  2118 
  2119 * subgoal_tac displays a warning if the new subgoal has type variables;
  2120 
  2121 * removed old README and Makefiles;
  2122 
  2123 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2124 
  2125 * removed obsolete init_pps and init_database;
  2126 
  2127 * deleted the obsolete tactical STATE, which was declared by
  2128     fun STATE tacfun st = tacfun st st;
  2129 
  2130 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2131 (which abbreviates $HOME);
  2132 
  2133 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2134 use isatool fixseq to adapt your ML programs (this works for fully
  2135 qualified references to the Sequence structure only!);
  2136 
  2137 * use_thy no longer requires writable current directory; it always
  2138 reloads .ML *and* .thy file, if either one is out of date;
  2139 
  2140 
  2141 *** Classical Reasoner ***
  2142 
  2143 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2144 tactics that use classical reasoning to simplify a subgoal without
  2145 splitting it into several subgoals;
  2146 
  2147 * Safe_tac: like safe_tac but uses the default claset;
  2148 
  2149 
  2150 *** Simplifier ***
  2151 
  2152 * added simplification meta rules:
  2153     (asm_)(full_)simplify: simpset -> thm -> thm;
  2154 
  2155 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2156 logics (again);
  2157 
  2158 * added prems argument to simplification procedures;
  2159 
  2160 * HOL, FOL, ZF: added infix function `addsplits':
  2161   instead of `<simpset> setloop (split_tac <thms>)'
  2162   you can simply write `<simpset> addsplits <thms>'
  2163 
  2164 
  2165 *** Syntax ***
  2166 
  2167 * TYPE('a) syntax for type reflection terms;
  2168 
  2169 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2170 
  2171 * pretty printer: changed order of mixfix annotation preference (again!);
  2172 
  2173 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2174 
  2175 
  2176 *** HOL ***
  2177 
  2178 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2179   with `addloop' of the simplifier to faciliate case splitting in premises.
  2180 
  2181 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2182 
  2183 * HOL/Auth: new protocol proofs including some for the Internet
  2184   protocol TLS;
  2185 
  2186 * HOL/Map: new theory of `maps' a la VDM;
  2187 
  2188 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2189 cancelling out common nat summands from =, <, <= (in)equalities, or
  2190 differences; simplification procedures nat_cancel_factor for
  2191 cancelling common factor from =, <, <= (in)equalities over natural
  2192 sums; nat_cancel contains both kinds of procedures, it is installed by
  2193 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2194 
  2195 * HOL/simplifier: terms of the form
  2196   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2197   are rewritten to
  2198   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2199   and those of the form
  2200   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2201   are rewritten to
  2202   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2203 
  2204 * HOL/datatype
  2205   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2206 
  2207   P(t_case f1 ... fn x) =
  2208      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2209         ...
  2210        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2211      )
  2212 
  2213   and a theorem `split_t_case_asm' of the form
  2214 
  2215   P(t_case f1 ... fn x) =
  2216     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2217         ...
  2218        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2219      )
  2220   which can be added to a simpset via `addsplits'. The existing theorems
  2221   expand_list_case and expand_option_case have been renamed to
  2222   split_list_case and split_option_case.
  2223 
  2224 * HOL/Arithmetic:
  2225   - `pred n' is automatically converted to `n-1'.
  2226     Users are strongly encouraged not to use `pred' any longer,
  2227     because it will disappear altogether at some point.
  2228   - Users are strongly encouraged to write "0 < n" rather than
  2229     "n ~= 0". Theorems and proof tools have been modified towards this
  2230     `standard'.
  2231 
  2232 * HOL/Lists:
  2233   the function "set_of_list" has been renamed "set" (and its theorems too);
  2234   the function "nth" now takes its arguments in the reverse order and
  2235   has acquired the infix notation "!" as in "xs!n".
  2236 
  2237 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2238 
  2239 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2240   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2241 
  2242 * HOL/record: extensible records with schematic structural subtyping
  2243 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2244 still lacks various theorems and concrete record syntax;
  2245 
  2246 
  2247 *** HOLCF ***
  2248 
  2249 * removed "axioms" and "generated by" sections;
  2250 
  2251 * replaced "ops" section by extended "consts" section, which is capable of
  2252   handling the continuous function space "->" directly;
  2253 
  2254 * domain package:
  2255   . proves theorems immediately and stores them in the theory,
  2256   . creates hierachical name space,
  2257   . now uses normal mixfix annotations (instead of cinfix...),
  2258   . minor changes to some names and values (for consistency),
  2259   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2260   . separator between mutual domain defs: changed "," to "and",
  2261   . improved handling of sort constraints;  now they have to
  2262     appear on the left-hand side of the equations only;
  2263 
  2264 * fixed LAM <x,y,zs>.b syntax;
  2265 
  2266 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2267 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2268 
  2269 
  2270 *** FOL and ZF ***
  2271 
  2272 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2273   with `addloop' of the simplifier to faciliate case splitting in premises.
  2274 
  2275 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2276 in HOL, they strip ALL and --> from proved theorems;
  2277 
  2278 
  2279 
  2280 New in Isabelle94-8 (May 1997)
  2281 ------------------------------
  2282 
  2283 *** General Changes ***
  2284 
  2285 * new utilities to build / run / maintain Isabelle etc. (in parts
  2286 still somewhat experimental); old Makefiles etc. still functional;
  2287 
  2288 * new 'Isabelle System Manual';
  2289 
  2290 * INSTALL text, together with ./configure and ./build scripts;
  2291 
  2292 * reimplemented type inference for greater efficiency, better error
  2293 messages and clean internal interface;
  2294 
  2295 * prlim command for dealing with lots of subgoals (an easier way of
  2296 setting goals_limit);
  2297 
  2298 
  2299 *** Syntax ***
  2300 
  2301 * supports alternative (named) syntax tables (parser and pretty
  2302 printer); internal interface is provided by add_modesyntax(_i);
  2303 
  2304 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2305 be used in conjunction with the Isabelle symbol font; uses the
  2306 "symbols" syntax table;
  2307 
  2308 * added token_translation interface (may translate name tokens in
  2309 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2310 the current print_mode); IMPORTANT: user print translation functions
  2311 are responsible for marking newly introduced bounds
  2312 (Syntax.mark_boundT);
  2313 
  2314 * token translations for modes "xterm" and "xterm_color" that display
  2315 names in bold, underline etc. or colors (which requires a color
  2316 version of xterm);
  2317 
  2318 * infixes may now be declared with names independent of their syntax;
  2319 
  2320 * added typed_print_translation (like print_translation, but may
  2321 access type of constant);
  2322 
  2323 
  2324 *** Classical Reasoner ***
  2325 
  2326 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2327 some limitations.  Blast_tac...
  2328   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2329   + ignores elimination rules that don't have the correct format
  2330         (the conclusion MUST be a formula variable)
  2331   + ignores types, which can make HOL proofs fail
  2332   + rules must not require higher-order unification, e.g. apply_type in ZF
  2333     [message "Function Var's argument not a bound variable" relates to this]
  2334   + its proof strategy is more general but can actually be slower
  2335 
  2336 * substitution with equality assumptions no longer permutes other
  2337 assumptions;
  2338 
  2339 * minor changes in semantics of addafter (now called addaltern); renamed
  2340 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2341 (and access functions for it);
  2342 
  2343 * improved combination of classical reasoner and simplifier:
  2344   + functions for handling clasimpsets
  2345   + improvement of addss: now the simplifier is called _after_ the
  2346     safe steps.
  2347   + safe variant of addss called addSss: uses safe simplifications
  2348     _during_ the safe steps. It is more complete as it allows multiple
  2349     instantiations of unknowns (e.g. with slow_tac).
  2350 
  2351 *** Simplifier ***
  2352 
  2353 * added interface for simplification procedures (functions that
  2354 produce *proven* rewrite rules on the fly, depending on current
  2355 redex);
  2356 
  2357 * ordering on terms as parameter (used for ordered rewriting);
  2358 
  2359 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2360 
  2361 * the solver is now split into a safe and an unsafe part.
  2362 This should be invisible for the normal user, except that the
  2363 functions setsolver and addsolver have been renamed to setSolver and
  2364 addSolver; added safe_asm_full_simp_tac;
  2365 
  2366 
  2367 *** HOL ***
  2368 
  2369 * a generic induction tactic `induct_tac' which works for all datatypes and
  2370 also for type `nat';
  2371 
  2372 * a generic case distinction tactic `exhaust_tac' which works for all
  2373 datatypes and also for type `nat';
  2374 
  2375 * each datatype comes with a function `size';
  2376 
  2377 * patterns in case expressions allow tuple patterns as arguments to
  2378 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2379 
  2380 * primrec now also works with type nat;
  2381 
  2382 * recdef: a new declaration form, allows general recursive functions to be
  2383 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2384 
  2385 * the constant for negation has been renamed from "not" to "Not" to
  2386 harmonize with FOL, ZF, LK, etc.;
  2387 
  2388 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2389 infinite lists;
  2390 
  2391 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2392 
  2393 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2394 problems in commutative rings, using axiomatic type classes for + and *;
  2395 
  2396 * more examples in HOL/MiniML and HOL/Auth;
  2397 
  2398 * more default rewrite rules for quantifiers, union/intersection;
  2399 
  2400 * a new constant `arbitrary == @x.False';
  2401 
  2402 * HOLCF/IOA replaces old HOL/IOA;
  2403 
  2404 * HOLCF changes: derived all rules and arities
  2405   + axiomatic type classes instead of classes
  2406   + typedef instead of faking type definitions
  2407   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2408   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2409   + eliminated the types void, one, tr
  2410   + use unit lift and bool lift (with translations) instead of one and tr
  2411   + eliminated blift from Lift3.thy (use Def instead of blift)
  2412   all eliminated rules are derived as theorems --> no visible changes ;
  2413 
  2414 
  2415 *** ZF ***
  2416 
  2417 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2418 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2419 as ZF_cs addSIs [equalityI];
  2420 
  2421 
  2422 
  2423 New in Isabelle94-7 (November 96)
  2424 ---------------------------------
  2425 
  2426 * allowing negative levels (as offsets) in prlev and choplev;
  2427 
  2428 * super-linear speedup for large simplifications;
  2429 
  2430 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2431 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2432 FAIL); can suppress it using the command Delsimps (ex_simps @
  2433 all_simps); De Morgan laws are also now included, by default;
  2434 
  2435 * improved printing of ==>  :  ~:
  2436 
  2437 * new object-logic "Sequents" adds linear logic, while replacing LK
  2438 and Modal (thanks to Sara Kalvala);
  2439 
  2440 * HOL/Auth: correctness proofs for authentication protocols;
  2441 
  2442 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2443 examples on HOL/Auth);
  2444 
  2445 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2446 the rewriter and classical reasoner simultaneously;
  2447 
  2448 * function uresult no longer returns theorems in "standard" format;
  2449 regain previous version by: val uresult = standard o uresult;
  2450 
  2451 
  2452 
  2453 New in Isabelle94-6
  2454 -------------------
  2455 
  2456 * oracles -- these establish an interface between Isabelle and trusted
  2457 external reasoners, which may deliver results as theorems;
  2458 
  2459 * proof objects (in particular record all uses of oracles);
  2460 
  2461 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2462 
  2463 * "constdefs" section in theory files;
  2464 
  2465 * "primrec" section (HOL) no longer requires names;
  2466 
  2467 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2468 
  2469 
  2470 
  2471 New in Isabelle94-5
  2472 -------------------
  2473 
  2474 * reduced space requirements;
  2475 
  2476 * automatic HTML generation from theories;
  2477 
  2478 * theory files no longer require "..." (quotes) around most types;
  2479 
  2480 * new examples, including two proofs of the Church-Rosser theorem;
  2481 
  2482 * non-curried (1994) version of HOL is no longer distributed;
  2483 
  2484 
  2485 
  2486 New in Isabelle94-4
  2487 -------------------
  2488 
  2489 * greatly reduced space requirements;
  2490 
  2491 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2492 
  2493 * searchable theorem database (see the section "Retrieving theorems" on
  2494 page 8 of the Reference Manual);
  2495 
  2496 * new examples, including Grabczewski's monumental case study of the
  2497 Axiom of Choice;
  2498 
  2499 * The previous version of HOL renamed to Old_HOL;
  2500 
  2501 * The new version of HOL (previously called CHOL) uses a curried syntax
  2502 for functions.  Application looks like f a b instead of f(a,b);
  2503 
  2504 * Mutually recursive inductive definitions finally work in HOL;
  2505 
  2506 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2507 translates to the operator "split";
  2508 
  2509 
  2510 
  2511 New in Isabelle94-3
  2512 -------------------
  2513 
  2514 * new infix operator, addss, allowing the classical reasoner to
  2515 perform simplification at each step of its search.  Example:
  2516         fast_tac (cs addss ss)
  2517 
  2518 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2519 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2520 look like (a,b) instead of <a,b>;
  2521 
  2522 * PLEASE NOTE: CHOL will eventually replace HOL!
  2523 
  2524 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2525 It translates to the operator "split".  A new theory of integers is available;
  2526 
  2527 * In ZF, integer numerals now denote two's-complement binary integers.
  2528 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2529 
  2530 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2531 of the Axiom of Choice;
  2532 
  2533 
  2534 
  2535 New in Isabelle94-2
  2536 -------------------
  2537 
  2538 * Significantly faster resolution;
  2539 
  2540 * the different sections in a .thy file can now be mixed and repeated
  2541 freely;
  2542 
  2543 * Database of theorems for FOL, HOL and ZF.  New
  2544 commands including qed, qed_goal and bind_thm store theorems in the database.
  2545 
  2546 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2547 a given theory (thms_of), or find out what theory a theorem was proved in
  2548 (theory_of_thm);
  2549 
  2550 * Bugs fixed in the inductive definition and datatype packages;
  2551 
  2552 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2553 and HOL_dup_cs obsolete;
  2554 
  2555 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2556 have been removed;
  2557 
  2558 * Simpler definition of function space in ZF;
  2559 
  2560 * new results about cardinal and ordinal arithmetic in ZF;
  2561 
  2562 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2563 types;
  2564 
  2565 
  2566 $Id$