NEWS
author paulson
Wed Mar 24 10:55:20 2004 +0100 (2004-03-24)
changeset 14480 14b7923b3307
parent 14464 72ad5f2a3803
child 14503 255ad604e08e
permissions -rw-r--r--
clarified
     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 arithmetic laws have gone. 
   102     Look for the general versions in Ring_and_Field (and Power if they concern
   103     exponentiation).
   104 
   105 * Type "rat" of the rational numbers is now available in HOL-Complex.
   106 
   107 * Records:
   108   - Record types are now by default printed with their type abbreviation
   109     instead of the list of all field types. This can be configured via
   110     the reference "print_record_type_abbr".
   111   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   112     (not enabled by default).
   113   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   114     EX x. x = sel r to True (not enabled by default).
   115   - Tactic "record_split_simp_tac" to split and simplify records added.
   116  
   117 * 'specification' command added, allowing for definition by
   118   specification.  There is also an 'ax_specification' command that
   119   introduces the new constants axiomatically.
   120 
   121 * arith(_tac) is now able to generate counterexamples for reals as well.
   122 
   123 * HOL-Algebra: new locale "ring" for non-commutative rings.
   124 
   125 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   126  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   127 
   128 * Unions and Intersections:
   129   The x-symbol output syntax of UN and INT has been changed
   130   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   131   i.e. the index formulae has become a subscript, like in normal math.
   132   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   133   The subscript version is also accepted as input syntax.
   134 
   135 * Unions and Intersections over Intervals:
   136   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   137   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   138   like in normal math, and corresponding versions for < and for intersection.
   139 
   140 * ML: the legacy theory structures Int and List have been removed. They had
   141   conflicted with ML Basis Library structures having the same names.
   142 
   143 * 'refute' command added to search for (finite) countermodels.  Only works
   144   for a fragment of HOL.  The installation of an external SAT solver is
   145   highly recommended.  See "HOL/Refute.thy" for details.
   146 
   147 
   148 New in Isabelle2003 (May 2003)
   149 --------------------------------
   150 
   151 *** General ***
   152 
   153 * Provers/simplifier:
   154 
   155   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   156     Assumptions are now subject to complete mutual simplification,
   157     not just from left to right. The simplifier now preserves
   158     the order of assumptions.
   159 
   160     Potential INCOMPATIBILITY:
   161 
   162     -- simp sometimes diverges where the old version did
   163        not, e.g. invoking simp on the goal
   164 
   165         [| P (f x); y = x; f x = f y |] ==> Q
   166 
   167        now gives rise to the infinite reduction sequence
   168 
   169         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   170 
   171        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   172        kind of problem.
   173 
   174     -- Tactics combining classical reasoner and simplification (such as auto)
   175        are also affected by this change, because many of them rely on
   176        simp. They may sometimes diverge as well or yield a different numbers
   177        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   178        in case of problems. Sometimes subsequent calls to the classical
   179        reasoner will fail because a preceeding call to the simplifier too
   180        eagerly simplified the goal, e.g. deleted redundant premises.
   181 
   182   - The simplifier trace now shows the names of the applied rewrite rules
   183 
   184   - You can limit the number of recursive invocations of the simplifier
   185     during conditional rewriting (where the simplifie tries to solve the
   186     conditions before applying the rewrite rule):
   187     ML "simp_depth_limit := n"
   188     where n is an integer. Thus you can force termination where previously
   189     the simplifier would diverge.
   190 
   191   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   192 
   193   - No longer aborts on failed congruence proof.  Instead, the
   194     congruence is ignored.
   195 
   196 * Pure: New generic framework for extracting programs from constructive
   197   proofs. See HOL/Extraction.thy for an example instantiation, as well
   198   as HOL/Extraction for some case studies.
   199 
   200 * Pure: The main goal of the proof state is no longer shown by default, only
   201 the subgoals. This behaviour is controlled by a new flag.
   202    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   203 (ML: Proof.show_main_goal).
   204 
   205 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   206 rules whose conclusion matches subgoal 1:
   207       PG menu: Isabelle/Isar -> Show me -> matching rules
   208 The rules are ordered by how closely they match the subgoal.
   209 In particular, rules that solve a subgoal outright are displayed first
   210 (or rather last, the way they are printed).
   211 (ML: ProofGeneral.print_intros())
   212 
   213 * Pure: New flag trace_unify_fail causes unification to print
   214 diagnostic information (PG: in trace buffer) when it fails. This is
   215 useful for figuring out why single step proofs like rule, erule or
   216 assumption failed.
   217 
   218 * Pure: Locale specifications now produce predicate definitions
   219 according to the body of text (covering assumptions modulo local
   220 definitions); predicate "loc_axioms" covers newly introduced text,
   221 while "loc" is cumulative wrt. all included locale expressions; the
   222 latter view is presented only on export into the global theory
   223 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   224 on the old view without predicates;
   225 
   226 * Pure: predefined locales "var" and "struct" are useful for sharing
   227 parameters (as in CASL, for example); just specify something like
   228 ``var x + var y + struct M'' as import;
   229 
   230 * Pure: improved thms_containing: proper indexing of facts instead of
   231 raw theorems; check validity of results wrt. current name space;
   232 include local facts of proof configuration (also covers active
   233 locales), cover fixed variables in index; may use "_" in term
   234 specification; an optional limit for the number of printed facts may
   235 be given (the default is 40);
   236 
   237 * Pure: disallow duplicate fact bindings within new-style theory files
   238 (batch-mode only);
   239 
   240 * Provers: improved induct method: assumptions introduced by case
   241 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   242 the goal statement); "foo" still refers to all facts collectively;
   243 
   244 * Provers: the function blast.overloaded has been removed: all constants
   245 are regarded as potentially overloaded, which improves robustness in exchange
   246 for slight decrease in efficiency;
   247 
   248 * Provers/linorder: New generic prover for transitivity reasoning over
   249 linear orders.  Note: this prover is not efficient!
   250 
   251 * Isar: preview of problems to finish 'show' now produce an error
   252 rather than just a warning (in interactive mode);
   253 
   254 
   255 *** HOL ***
   256 
   257 * arith(_tac)
   258 
   259  - Produces a counter example if it cannot prove a goal.
   260    Note that the counter example may be spurious if the goal is not a formula
   261    of quantifier-free linear arithmetic.
   262    In ProofGeneral the counter example appears in the trace buffer.
   263 
   264  - Knows about div k and mod k where k is a numeral of type nat or int.
   265 
   266  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   267    linear arithmetic fails. This takes account of quantifiers and divisibility.
   268    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   269 
   270 * simp's arithmetic capabilities have been enhanced a bit: it now
   271 takes ~= in premises into account (by performing a case split);
   272 
   273 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   274 are distributed over a sum of terms;
   275 
   276 * New tactic "trans_tac" and method "trans" instantiate
   277 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   278 "<=", "<" and "="). 
   279 
   280 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   281 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   282 
   283 * 'typedef' command has new option "open" to suppress the set
   284 definition;
   285 
   286 * functions Min and Max on finite sets have been introduced (theory
   287 Finite_Set);
   288 
   289 * attribute [symmetric] now works for relations as well; it turns
   290 (x,y) : R^-1 into (y,x) : R, and vice versa;
   291 
   292 * induct over a !!-quantified statement (say !!x1..xn):
   293   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   294 
   295 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   296 %x. None. Warning: empty_def now refers to the previously hidden definition
   297 of the empty set.
   298 
   299 * Algebra: formalization of classical algebra.  Intended as base for
   300 any algebraic development in Isabelle.  Currently covers group theory
   301 (up to Sylow's theorem) and ring theory (Universal Property of
   302 Univariate Polynomials).  Contributions welcome;
   303 
   304 * GroupTheory: deleted, since its material has been moved to Algebra;
   305 
   306 * Complex: new directory of the complex numbers with numeric constants, 
   307 nonstandard complex numbers, and some complex analysis, standard and 
   308 nonstandard (Jacques Fleuriot);
   309 
   310 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   311 
   312 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   313 Fleuriot);
   314 
   315 * Real/HahnBanach: updated and adapted to locales;
   316 
   317 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   318 Gray and Kramer);
   319 
   320 * UNITY: added the Meier-Sanders theory of progress sets;
   321 
   322 * MicroJava: bytecode verifier and lightweight bytecode verifier
   323 as abstract algorithms, instantiated to the JVM;
   324 
   325 * Bali: Java source language formalization. Type system, operational
   326 semantics, axiomatic semantics. Supported language features:
   327 classes, interfaces, objects,virtual methods, static methods,
   328 static/instance fields, arrays, access modifiers, definite
   329 assignment, exceptions.
   330 
   331 
   332 *** ZF ***
   333 
   334 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   335 universe, etc.);
   336 
   337 * Main ZF: virtually all theories converted to new-style format;
   338 
   339 
   340 *** ML ***
   341 
   342 * Pure: Tactic.prove provides sane interface for internal proofs;
   343 omits the infamous "standard" operation, so this is more appropriate
   344 than prove_goalw_cterm in many situations (e.g. in simprocs);
   345 
   346 * Pure: improved error reporting of simprocs;
   347 
   348 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   349 up simprocs;
   350 
   351 
   352 *** Document preparation ***
   353 
   354 * uses \par instead of \\ for line breaks in theory text. This may
   355 shift some page breaks in large documents. To get the old behaviour
   356 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   357 
   358 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   359 other packages
   360 
   361 * \<euro> now needs package babel/greek instead of marvosym (which
   362 broke \Rightarrow)
   363 
   364 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   365 textcomp package)
   366 
   367 
   368 New in Isabelle2002 (March 2002)
   369 --------------------------------
   370 
   371 *** Document preparation ***
   372 
   373 * greatly simplified document preparation setup, including more
   374 graceful interpretation of isatool usedir -i/-d/-D options, and more
   375 instructive isatool mkdir; users should basically be able to get
   376 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   377 users may run a separate document processing stage manually like this:
   378 "isatool usedir -D output HOL Test && isatool document Test/output";
   379 
   380 * theory dependency graph may now be incorporated into documents;
   381 isatool usedir -g true will produce session_graph.eps/.pdf for use
   382 with \includegraphics of LaTeX;
   383 
   384 * proper spacing of consecutive markup elements, especially text
   385 blocks after section headings;
   386 
   387 * support bold style (for single symbols only), input syntax is like
   388 this: "\<^bold>\<alpha>" or "\<^bold>A";
   389 
   390 * \<bullet> is now output as bold \cdot by default, which looks much
   391 better in printed text;
   392 
   393 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   394 note that these symbols are currently unavailable in Proof General /
   395 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   396 
   397 * isatool latex no longer depends on changed TEXINPUTS, instead
   398 isatool document copies the Isabelle style files to the target
   399 location;
   400 
   401 
   402 *** Isar ***
   403 
   404 * Pure/Provers: improved proof by cases and induction;
   405   - 'case' command admits impromptu naming of parameters (such as
   406     "case (Suc n)");
   407   - 'induct' method divinates rule instantiation from the inductive
   408     claim; no longer requires excessive ?P bindings for proper
   409     instantiation of cases;
   410   - 'induct' method properly enumerates all possibilities of set/type
   411     rules; as a consequence facts may be also passed through *type*
   412     rules without further ado;
   413   - 'induct' method now derives symbolic cases from the *rulified*
   414     rule (before it used to rulify cases stemming from the internal
   415     atomized version); this means that the context of a non-atomic
   416     statement becomes is included in the hypothesis, avoiding the
   417     slightly cumbersome show "PROP ?case" form;
   418   - 'induct' may now use elim-style induction rules without chaining
   419     facts, using ``missing'' premises from the goal state; this allows
   420     rules stemming from inductive sets to be applied in unstructured
   421     scripts, while still benefitting from proper handling of non-atomic
   422     statements; NB: major inductive premises need to be put first, all
   423     the rest of the goal is passed through the induction;
   424   - 'induct' proper support for mutual induction involving non-atomic
   425     rule statements (uses the new concept of simultaneous goals, see
   426     below);
   427   - append all possible rule selections, but only use the first
   428     success (no backtracking);
   429   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   430   - undeclared rule case names default to numbers 1, 2, 3, ...;
   431   - added 'print_induct_rules' (covered by help item in recent Proof
   432     General versions);
   433   - moved induct/cases attributes to Pure, methods to Provers;
   434   - generic method setup instantiated for FOL and HOL;
   435 
   436 * Pure: support multiple simultaneous goal statements, for example
   437 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   438 meta-level mechanism, this acts as if several individual goals had
   439 been stated separately; in particular common proof methods need to be
   440 repeated in order to cover all claims; note that a single elimination
   441 step is *not* sufficient to establish the two conjunctions, so this
   442 fails:
   443 
   444   assume "A & B" then have A and B ..   (*".." fails*)
   445 
   446 better use "obtain" in situations as above; alternative refer to
   447 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   448 
   449 * Pure: proper integration with ``locales''; unlike the original
   450 version by Florian Kammüller, Isar locales package high-level proof
   451 contexts rather than raw logical ones (e.g. we admit to include
   452 attributes everywhere); operations on locales include merge and
   453 rename; support for implicit arguments (``structures''); simultaneous
   454 type-inference over imports and text; see also HOL/ex/Locales.thy for
   455 some examples;
   456 
   457 * Pure: the following commands have been ``localized'', supporting a
   458 target locale specification "(in name)": 'lemma', 'theorem',
   459 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   460 stored both within the locale and at the theory level (exported and
   461 qualified by the locale name);
   462 
   463 * Pure: theory goals may now be specified in ``long'' form, with
   464 ad-hoc contexts consisting of arbitrary locale elements. for example
   465 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   466 definitions may be given, too); the result is a meta-level rule with
   467 the context elements being discharged in the obvious way;
   468 
   469 * Pure: new proof command 'using' allows to augment currently used
   470 facts after a goal statement ('using' is syntactically analogous to
   471 'apply', but acts on the goal's facts only); this allows chained facts
   472 to be separated into parts given before and after a claim, as in
   473 ``from a and b have C using d and e <proof>'';
   474 
   475 * Pure: renamed "antecedent" case to "rule_context";
   476 
   477 * Pure: new 'judgment' command records explicit information about the
   478 object-logic embedding (used by several tools internally); no longer
   479 use hard-wired "Trueprop";
   480 
   481 * Pure: added 'corollary' command;
   482 
   483 * Pure: fixed 'token_translation' command;
   484 
   485 * Pure: removed obsolete 'exported' attribute;
   486 
   487 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   488 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   489 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   490 
   491 * Pure: method 'atomize' presents local goal premises as object-level
   492 statements (atomic meta-level propositions); setup controlled via
   493 rewrite rules declarations of 'atomize' attribute; example
   494 application: 'induct' method with proper rule statements in improper
   495 proof *scripts*;
   496 
   497 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   498 now consider the syntactic context of assumptions, giving a better
   499 chance to get type-inference of the arguments right (this is
   500 especially important for locales);
   501 
   502 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   503 mode;
   504 
   505 * Pure/obtain: the formal conclusion "thesis", being marked as
   506 ``internal'', may no longer be reference directly in the text;
   507 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   508 situations;
   509 
   510 * Pure: generic 'sym' attribute which declares a rule both as pure
   511 'elim?' and for the 'symmetric' operation;
   512 
   513 * Pure: marginal comments ``--'' may now occur just anywhere in the
   514 text; the fixed correlation with particular command syntax has been
   515 discontinued;
   516 
   517 * Pure: new method 'rules' is particularly well-suited for proof
   518 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   519 but often produces more compact proof terms with less detours;
   520 
   521 * Pure/Provers/classical: simplified integration with pure rule
   522 attributes and methods; the classical "intro?/elim?/dest?"
   523 declarations coincide with the pure ones; the "rule" method no longer
   524 includes classically swapped intros; "intro" and "elim" methods no
   525 longer pick rules from the context; also got rid of ML declarations
   526 AddXIs/AddXEs/AddXDs; all of this has some potential for
   527 INCOMPATIBILITY;
   528 
   529 * Provers/classical: attribute 'swapped' produces classical inversions
   530 of introduction rules;
   531 
   532 * Provers/simplifier: 'simplified' attribute may refer to explicit
   533 rules instead of full simplifier context; 'iff' attribute handles
   534 conditional rules;
   535 
   536 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   537 
   538 * HOL: 'recdef' now fails on unfinished automated proofs, use
   539 "(permissive)" option to recover old behavior;
   540 
   541 * HOL: 'inductive' no longer features separate (collective) attributes
   542 for 'intros' (was found too confusing);
   543 
   544 * HOL: properly declared induction rules less_induct and
   545 wf_induct_rule;
   546 
   547 
   548 *** HOL ***
   549 
   550 * HOL: moved over to sane numeral syntax; the new policy is as
   551 follows:
   552 
   553   - 0 and 1 are polymorphic constants, which are defined on any
   554   numeric type (nat, int, real etc.);
   555 
   556   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   557   binary representation internally;
   558 
   559   - type nat has special constructor Suc, and generally prefers Suc 0
   560   over 1::nat and Suc (Suc 0) over 2::nat;
   561 
   562 This change may cause significant problems of INCOMPATIBILITY; here
   563 are some hints on converting existing sources:
   564 
   565   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   566   entities, so expressions involving "-" (unary or binary minus) need
   567   to be spaced properly;
   568 
   569   - existing occurrences of "1" may need to be constraint "1::nat" or
   570   even replaced by Suc 0; similar for old "2";
   571 
   572   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   573 
   574   - remove all special provisions on numerals in proofs;
   575 
   576 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   577 representation (depends on bin_arith_simps in the default context);
   578 
   579 * HOL: symbolic syntax for x^2 (numeral 2);
   580 
   581 * HOL: the class of all HOL types is now called "type" rather than
   582 "term"; INCOMPATIBILITY, need to adapt references to this type class
   583 in axclass/classes, instance/arities, and (usually rare) occurrences
   584 in typings (of consts etc.); internally the class is called
   585 "HOL.type", ML programs should refer to HOLogic.typeS;
   586 
   587 * HOL/record package improvements:
   588   - new derived operations "fields" to build a partial record section,
   589     "extend" to promote a fixed record to a record scheme, and
   590     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   591     declared as simp by default;
   592   - shared operations ("more", "fields", etc.) now need to be always
   593     qualified) --- potential INCOMPATIBILITY;
   594   - removed "make_scheme" operations (use "make" with "extend") --
   595     INCOMPATIBILITY;
   596   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   597   - provides cases/induct rules for use with corresponding Isar
   598     methods (for concrete records, record schemes, concrete more
   599     parts, and schematic more parts -- in that order);
   600   - internal definitions directly based on a light-weight abstract
   601     theory of product types over typedef rather than datatype;
   602 
   603 * HOL: generic code generator for generating executable ML code from
   604 specifications; specific support for HOL constructs such as inductive
   605 datatypes and sets, as well as recursive functions; can be invoked
   606 via 'generate_code' theory section;
   607 
   608 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   609 
   610 * HOL: consolidated and renamed several theories.  In particular:
   611 	Ord.thy has been absorbed into HOL.thy
   612 	String.thy has been absorbed into List.thy
   613  
   614 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   615 (beware of argument permutation!);
   616 
   617 * HOL: linorder_less_split superseded by linorder_cases;
   618 
   619 * HOL/List: "nodups" renamed to "distinct";
   620 
   621 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   622 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   623   - Ex_def has changed, now need to use some_eq_ex
   624 
   625 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   626 in this (rare) case use:
   627 
   628   delSWrapper "split_all_tac"
   629   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   630 
   631 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   632 MAY FAIL;
   633 
   634 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   635 Isabelle's type classes, ^ on functions and relations has too general
   636 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   637 necessary to attach explicit type constraints;
   638 
   639 * HOL/Relation: the prefix name of the infix "O" has been changed from
   640 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   641 renamed accordingly (eg "compI" -> "rel_compI").
   642 
   643 * HOL: syntax translations now work properly with numerals and records
   644 expressions;
   645 
   646 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   647 of "lam" -- INCOMPATIBILITY;
   648 
   649 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   650 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   651 renamed "Product_Type.unit";
   652 
   653 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   654 
   655 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   656 the "cases" method);
   657 
   658 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   659 Florian Kammüller);
   660 
   661 * HOL/IMP: updated and converted to new-style theory format; several
   662 parts turned into readable document, with proper Isar proof texts and
   663 some explanations (by Gerwin Klein);
   664 
   665 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   666 
   667 * HOL-Hyperreal is now a logic image;
   668 
   669 
   670 *** HOLCF ***
   671 
   672 * Isar: consts/constdefs supports mixfix syntax for continuous
   673 operations;
   674 
   675 * Isar: domain package adapted to new-style theory format, e.g. see
   676 HOLCF/ex/Dnat.thy;
   677 
   678 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   679 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   680 lift.induct_tac, always use UU instead of Undef;
   681 
   682 * HOLCF/IMP: updated and converted to new-style theory;
   683 
   684 
   685 *** ZF ***
   686 
   687 * Isar: proper integration of logic-specific tools and packages,
   688 including theory commands '(co)inductive', '(co)datatype',
   689 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   690 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   691 
   692 * theory Main no longer includes AC; for the Axiom of Choice, base
   693 your theory on Main_ZFC;
   694 
   695 * the integer library now covers quotients and remainders, with many
   696 laws relating division to addition, multiplication, etc.;
   697 
   698 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   699 typeless version of the formalism;
   700 
   701 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   702 format;
   703 
   704 * ZF/Induct: new directory for examples of inductive definitions,
   705 including theory Multiset for multiset orderings; converted to
   706 new-style theory format;
   707 
   708 * ZF: many new theorems about lists, ordinals, etc.;
   709 
   710 
   711 *** General ***
   712 
   713 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   714 variable proof controls level of detail: 0 = no proofs (only oracle
   715 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   716 also ref manual for further ML interfaces;
   717 
   718 * Pure/axclass: removed obsolete ML interface
   719 goal_subclass/goal_arity;
   720 
   721 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   722 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   723 separate tokens, so expressions involving minus need to be spaced
   724 properly;
   725 
   726 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   727 rather than "infixl" or "infixr";
   728 
   729 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   730 sort constraint specifications in type inference; e.g. "x::_::foo"
   731 ensures that the type of "x" is of sort "foo" (but not necessarily a
   732 type variable);
   733 
   734 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   735 control output of nested => (types); the default behavior is
   736 "type_brackets";
   737 
   738 * Pure/syntax: builtin parse translation for "_constify" turns valued
   739 tokens into AST constants;
   740 
   741 * Pure/syntax: prefer later declarations of translations and print
   742 translation functions; potential INCOMPATIBILITY: need to reverse
   743 multiple declarations for same syntax element constant;
   744 
   745 * Pure/show_hyps reset by default (in accordance to existing Isar
   746 practice);
   747 
   748 * Provers/classical: renamed addaltern to addafter, addSaltern to
   749 addSafter;
   750 
   751 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   752 as well;
   753 
   754 * system: tested support for MacOS X; should be able to get Isabelle +
   755 Proof General to work in a plain Terminal after installing Poly/ML
   756 (e.g. from the Isabelle distribution area) and GNU bash alone
   757 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   758 support requires further installations, e.g. from
   759 http://fink.sourceforge.net/);
   760 
   761 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   762 
   763 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   764 of 40 MB), cf. ML_OPTIONS;
   765 
   766 * system: Proof General keywords specification is now part of the
   767 Isabelle distribution (see etc/isar-keywords.el);
   768 
   769 * system: support for persistent Proof General sessions (refrain from
   770 outdating all loaded theories on startup); user may create writable
   771 logic images like this: ``isabelle -q HOL Test'';
   772 
   773 * system: smart selection of Isabelle process versus Isabelle
   774 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   775 run both "isabelle" and "Isabelle" even if file names are badly
   776 damaged (executable inspects the case of the first letter of its own
   777 name); added separate "isabelle-process" and "isabelle-interface";
   778 
   779 * system: refrain from any attempt at filtering input streams; no
   780 longer support ``8bit'' encoding of old isabelle font, instead proper
   781 iso-latin characters may now be used; the related isatools
   782 "symbolinput" and "nonascii" have disappeared as well;
   783 
   784 * system: removed old "xterm" interface (the print modes "xterm" and
   785 "xterm_color" are still available for direct use in a suitable
   786 terminal);
   787 
   788 
   789 
   790 New in Isabelle99-2 (February 2001)
   791 -----------------------------------
   792 
   793 *** Overview of INCOMPATIBILITIES ***
   794 
   795 * HOL: please note that theories in the Library and elsewhere often use the
   796 new-style (Isar) format; to refer to their theorems in an ML script you must
   797 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   798 
   799 * HOL: inductive package no longer splits induction rule aggressively,
   800 but only as far as specified by the introductions given; the old
   801 format may be recovered via ML function complete_split_rule or attribute
   802 'split_rule (complete)';
   803 
   804 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   805 gfp_Tarski to gfp_unfold;
   806 
   807 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   808 
   809 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   810 relation); infix "^^" has been renamed "``"; infix "``" has been
   811 renamed "`"; "univalent" has been renamed "single_valued";
   812 
   813 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   814 operation;
   815 
   816 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   817 
   818 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   819 
   820 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   821 consequence, it is no longer monotonic wrt. the local goal context
   822 (which is now passed through the inductive cases);
   823 
   824 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   825 \<gg> to \<ggreater>;
   826 
   827 
   828 *** Document preparation ***
   829 
   830 * \isabellestyle{NAME} selects version of Isabelle output (currently
   831 available: are "it" for near math-mode best-style output, "sl" for
   832 slanted text style, and "tt" for plain type-writer; if no
   833 \isabellestyle command is given, output is according to slanted
   834 type-writer);
   835 
   836 * support sub/super scripts (for single symbols only), input syntax is
   837 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   838 
   839 * some more standard symbols; see Appendix A of the system manual for
   840 the complete list of symbols defined in isabellesym.sty;
   841 
   842 * improved isabelle style files; more abstract symbol implementation
   843 (should now use \isamath{...} and \isatext{...} in custom symbol
   844 definitions);
   845 
   846 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   847 state; Note that presentation of goal states does not conform to
   848 actual human-readable proof documents.  Please do not include goal
   849 states into document output unless you really know what you are doing!
   850 
   851 * proper indentation of antiquoted output with proportional LaTeX
   852 fonts;
   853 
   854 * no_document ML operator temporarily disables LaTeX document
   855 generation;
   856 
   857 * isatool unsymbolize tunes sources for plain ASCII communication;
   858 
   859 
   860 *** Isar ***
   861 
   862 * Pure: Isar now suffers initial goal statements to contain unbound
   863 schematic variables (this does not conform to actual readable proof
   864 documents, due to unpredictable outcome and non-compositional proof
   865 checking); users who know what they are doing may use schematic goals
   866 for Prolog-style synthesis of proven results;
   867 
   868 * Pure: assumption method (an implicit finishing) now handles actual
   869 rules as well;
   870 
   871 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   872 initial goal, declare "that" only as Pure intro (only for single
   873 steps); the "that" rule assumption may now be involved in implicit
   874 finishing, thus ".." becomes a feasible for trivial obtains;
   875 
   876 * Pure: default proof step now includes 'intro_classes'; thus trivial
   877 instance proofs may be performed by "..";
   878 
   879 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   880 statements as well;
   881 
   882 * Pure: more robust selection of calculational rules;
   883 
   884 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   885 rule (as well as the assumption rule);
   886 
   887 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   888 lemmas, using the graph browser tool;
   889 
   890 * Pure: predict failure of "show" in interactive mode;
   891 
   892 * Pure: 'thms_containing' now takes actual terms as arguments;
   893 
   894 * HOL: improved method 'induct' --- now handles non-atomic goals
   895 (potential INCOMPATIBILITY); tuned error handling;
   896 
   897 * HOL: cases and induct rules now provide explicit hints about the
   898 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   899 any remaining facts are inserted into the goal verbatim;
   900 
   901 * HOL: local contexts (aka cases) may now contain term bindings as
   902 well; the 'cases' and 'induct' methods new provide a ?case binding for
   903 the result to be shown in each case;
   904 
   905 * HOL: added 'recdef_tc' command;
   906 
   907 * isatool convert assists in eliminating legacy ML scripts;
   908 
   909 
   910 *** HOL ***
   911 
   912 * HOL/Library: a collection of generic theories to be used together
   913 with main HOL; the theory loader path already includes this directory
   914 by default; the following existing theories have been moved here:
   915 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   916 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   917 
   918 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   919 modelling and verification task performed in Isabelle/HOL +
   920 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   921 
   922 * HOL/Algebra: special summation operator SUM no longer exists, it has
   923 been replaced by setsum; infix 'assoc' now has priority 50 (like
   924 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   925 'domain', this makes the theory consistent with mathematical
   926 literature;
   927 
   928 * HOL basics: added overloaded operations "inverse" and "divide"
   929 (infix "/"), syntax for generic "abs" operation, generic summation
   930 operator \<Sum>;
   931 
   932 * HOL/typedef: simplified package, provide more useful rules (see also
   933 HOL/subset.thy);
   934 
   935 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   936 now expressed as a proper nested rule (old-style tactic scripts may
   937 require atomize_strip_tac to cope with non-atomic premises);
   938 
   939 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   940 to "split_conv" (old name still available for compatibility);
   941 
   942 * HOL: improved concrete syntax for strings (e.g. allows translation
   943 rules with string literals);
   944 
   945 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   946  and Fleuriot's mechanization of analysis, including the transcendental
   947  functions for the reals;
   948 
   949 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   950 
   951 
   952 *** CTT ***
   953 
   954 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   955 "lam" is displayed as TWO lambda-symbols
   956 
   957 * CTT: theory Main now available, containing everything (that is, Bool
   958 and Arith);
   959 
   960 
   961 *** General ***
   962 
   963 * Pure: the Simplifier has been implemented properly as a derived rule
   964 outside of the actual kernel (at last!); the overall performance
   965 penalty in practical applications is about 50%, while reliability of
   966 the Isabelle inference kernel has been greatly improved;
   967 
   968 * print modes "brackets" and "no_brackets" control output of nested =>
   969 (types) and ==> (props); the default behaviour is "brackets";
   970 
   971 * Provers: fast_tac (and friends) now handle actual object-logic rules
   972 as assumptions as well;
   973 
   974 * system: support Poly/ML 4.0;
   975 
   976 * system: isatool install handles KDE version 1 or 2;
   977 
   978 
   979 
   980 New in Isabelle99-1 (October 2000)
   981 ----------------------------------
   982 
   983 *** Overview of INCOMPATIBILITIES ***
   984 
   985 * HOL: simplification of natural numbers is much changed; to partly
   986 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   987 issue the following ML commands:
   988 
   989   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   990   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   991 
   992 * HOL: simplification no longer dives into case-expressions; this is
   993 controlled by "t.weak_case_cong" for each datatype t;
   994 
   995 * HOL: nat_less_induct renamed to less_induct;
   996 
   997 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   998 fixsome to patch .thy and .ML sources automatically;
   999 
  1000   select_equality  -> some_equality
  1001   select_eq_Ex     -> some_eq_ex
  1002   selectI2EX       -> someI2_ex
  1003   selectI2         -> someI2
  1004   selectI          -> someI
  1005   select1_equality -> some1_equality
  1006   Eps_sym_eq       -> some_sym_eq_trivial
  1007   Eps_eq           -> some_eq_trivial
  1008 
  1009 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1010 
  1011 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1012 instead);
  1013 
  1014 * HOL: the recursion equations generated by 'recdef' are now called
  1015 f.simps instead of f.rules;
  1016 
  1017 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1018 
  1019 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1020 sometimes be needed;
  1021 
  1022 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1023 
  1024 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1025 
  1026 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1027 product is now "<*>" instead of "Times"; the lexicographic product is
  1028 now "<*lex*>" instead of "**";
  1029 
  1030 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1031 of main HOL, but was unused); better use HOL's datatype package;
  1032 
  1033 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1034 the old syntax may be recovered as follows:
  1035 
  1036   syntax (symbols)
  1037     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1038       (infixl "\\<oplus>" 100)
  1039 
  1040 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1041 
  1042 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1043 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1044 internally;
  1045 
  1046 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1047 changed from A/r to A//r;
  1048 
  1049 * ZF: new treatment of arithmetic (nat & int) may break some old
  1050 proofs;
  1051 
  1052 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1053 rulify -> rule_format, elimify -> elim_format, ...);
  1054 
  1055 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1056 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1057 should have to change intro!! to intro? only); replaced "delrule" by
  1058 "rule del";
  1059 
  1060 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1061 
  1062 * Provers: strengthened force_tac by using new first_best_tac;
  1063 
  1064 * LaTeX document preparation: several changes of isabelle.sty (see
  1065 lib/texinputs);
  1066 
  1067 
  1068 *** Document preparation ***
  1069 
  1070 * formal comments (text blocks etc.) in new-style theories may now
  1071 contain antiquotations of thm/prop/term/typ/text to be presented
  1072 according to latex print mode; concrete syntax is like this:
  1073 @{term[show_types] "f(x) = a + x"};
  1074 
  1075 * isatool mkdir provides easy setup of Isabelle session directories,
  1076 including proper document sources;
  1077 
  1078 * generated LaTeX sources are now deleted after successful run
  1079 (isatool document -c); may retain a copy somewhere else via -D option
  1080 of isatool usedir;
  1081 
  1082 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1083 style files, achieving self-contained LaTeX sources and simplifying
  1084 LaTeX debugging;
  1085 
  1086 * old-style theories now produce (crude) LaTeX output as well;
  1087 
  1088 * browser info session directories are now self-contained (may be put
  1089 on WWW server seperately); improved graphs of nested sessions; removed
  1090 graph for 'all sessions';
  1091 
  1092 * several improvements in isabelle style files; \isabellestyle{it}
  1093 produces fake math mode output; \isamarkupheader is now \section by
  1094 default; see lib/texinputs/isabelle.sty etc.;
  1095 
  1096 
  1097 *** Isar ***
  1098 
  1099 * Isar/Pure: local results and corresponding term bindings are now
  1100 subject to Hindley-Milner polymorphism (similar to ML); this
  1101 accommodates incremental type-inference very nicely;
  1102 
  1103 * Isar/Pure: new derived language element 'obtain' supports
  1104 generalized existence reasoning;
  1105 
  1106 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1107 support accumulation of results, without applying any rules yet;
  1108 useful to collect intermediate results without explicit name
  1109 references, and for use with transitivity rules with more than 2
  1110 premises;
  1111 
  1112 * Isar/Pure: scalable support for case-analysis type proofs: new
  1113 'case' language element refers to local contexts symbolically, as
  1114 produced by certain proof methods; internally, case names are attached
  1115 to theorems as "tags";
  1116 
  1117 * Isar/Pure: theory command 'hide' removes declarations from
  1118 class/type/const name spaces;
  1119 
  1120 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1121 indicate potential overloading;
  1122 
  1123 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1124 
  1125 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1126 "{a,b,c}" instead of {a,b,c};
  1127 
  1128 * Isar/Pure now provides its own version of intro/elim/dest
  1129 attributes; useful for building new logics, but beware of confusion
  1130 with the version in Provers/classical;
  1131 
  1132 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1133 case name 'antecedent';
  1134 
  1135 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1136 to the current context is now done automatically);
  1137 
  1138 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1139 for definining proof methods in ML;
  1140 
  1141 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1142 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1143 most cases, one should have to change intro!! to intro? only);
  1144 replaced "delrule" by "rule del";
  1145 
  1146 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1147 'symmetric' attribute (the latter supercedes [RS sym]);
  1148 
  1149 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1150 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1151 well (including splits);
  1152 
  1153 * Isar/Provers: Simplifier and Classical methods now support all kind
  1154 of modifiers used in the past, including 'cong', 'iff', etc.
  1155 
  1156 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1157 of Simplifier and Classical reasoner);
  1158 
  1159 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1160 now support named cases; major packages (inductive, datatype, primrec,
  1161 recdef) support case names and properly name parameters;
  1162 
  1163 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1164 monotonicity conditions are extracted to be proven at end of
  1165 calculations;
  1166 
  1167 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1168 method anyway;
  1169 
  1170 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1171 split_if split_if_asm; datatype package provides theorems foo.splits =
  1172 foo.split foo.split_asm for each datatype;
  1173 
  1174 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1175 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1176 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1177 use "(cases (simplified))" method in proper proof texts);
  1178 
  1179 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1180 
  1181 * Isar: names of theorems etc. may be natural numbers as well;
  1182 
  1183 * Isar: 'pr' command: optional arguments for goals_limit and
  1184 ProofContext.prems_limit; no longer prints theory contexts, but only
  1185 proof states;
  1186 
  1187 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1188 additional print modes to be specified; e.g. "pr(latex)" will print
  1189 proof state according to the Isabelle LaTeX style;
  1190 
  1191 * Isar: improved support for emulating tactic scripts, including proof
  1192 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1193 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1194 (for HOL datatypes);
  1195 
  1196 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1197 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1198 'proof method scripts' have to be in depth-first order;
  1199 
  1200 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1201 
  1202 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1203 should instead use individual commands for printing items
  1204 (print_commands, print_methods etc.);
  1205 
  1206 * Isar: added 'nothing' --- the empty list of theorems;
  1207 
  1208 
  1209 *** HOL ***
  1210 
  1211 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1212 corresponding virtual machine and a specification of its bytecode
  1213 verifier and a lightweight bytecode verifier, including proofs of
  1214 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1215 Cornelia Pusch (see also the homepage of project Bali at
  1216 http://isabelle.in.tum.de/Bali/);
  1217 
  1218 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1219 Clemens Ballarin;
  1220 
  1221 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1222 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1223 Rasmussen;
  1224 
  1225 * HOL/Lattice: fundamental concepts of lattice theory and order
  1226 structures, including duals, properties of bounds versus algebraic
  1227 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1228 Theorem for complete lattices etc.; may also serve as a demonstration
  1229 for abstract algebraic reasoning using axiomatic type classes, and
  1230 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1231 
  1232 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1233 von Oheimb;
  1234 
  1235 * HOL/IMPP: extension of IMP with local variables and mutually
  1236 recursive procedures, by David von Oheimb;
  1237 
  1238 * HOL/Lambda: converted into new-style theory and document;
  1239 
  1240 * HOL/ex/Multiquote: example of multiple nested quotations and
  1241 anti-quotations -- basically a generalized version of de-Bruijn
  1242 representation; very useful in avoiding lifting of operations;
  1243 
  1244 * HOL/record: added general record equality rule to simpset; fixed
  1245 select-update simplification procedure to handle extended records as
  1246 well; admit "r" as field name;
  1247 
  1248 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1249 other numeric types and also as the identity of groups, rings, etc.;
  1250 
  1251 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1252 Types nat and int belong to this axclass;
  1253 
  1254 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1255    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1256    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1257   two terms #m*u and #n*u are replaced by #(m+n)*u
  1258     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1259   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1260     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1261 
  1262 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1263 powerful prover for predicate logic but knows nothing of clasets; see
  1264 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1265 
  1266 * HOL: new version of "case_tac" subsumes both boolean case split and
  1267 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1268 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1269 
  1270 * HOL: simplification no longer dives into case-expressions: only the
  1271 selector expression is simplified, but not the remaining arms; to
  1272 enable full simplification of case-expressions for datatype t, you may
  1273 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1274 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1275 
  1276 * HOL/recdef: the recursion equations generated by 'recdef' for
  1277 function 'f' are now called f.simps instead of f.rules; if all
  1278 termination conditions are proved automatically, these simplification
  1279 rules are added to the simpset, as in primrec; rules may be named
  1280 individually as well, resulting in a separate list of theorems for
  1281 each equation;
  1282 
  1283 * HOL/While is a new theory that provides a while-combinator. It
  1284 permits the definition of tail-recursive functions without the
  1285 provision of a termination measure. The latter is necessary once the
  1286 invariant proof rule for while is applied.
  1287 
  1288 * HOL: new (overloaded) notation for the set of elements below/above
  1289 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1290 
  1291 * HOL: theorems impI, allI, ballI bound as "strip";
  1292 
  1293 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1294 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1295 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1296 
  1297 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1298 
  1299 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1300 main HOL, but was unused);
  1301 
  1302 * HOL: fewer consts declared as global (e.g. have to refer to
  1303 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1304 
  1305 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1306 in case of overlap with user translations (e.g. judgements over
  1307 tuples); (note that the underlying logical represenation is still
  1308 bogus);
  1309 
  1310 
  1311 *** ZF ***
  1312 
  1313 * ZF: simplification automatically cancels common terms in arithmetic
  1314 expressions over nat and int;
  1315 
  1316 * ZF: new treatment of nat to minimize type-checking: all operators
  1317 coerce their operands to a natural number using the function natify,
  1318 making the algebraic laws unconditional;
  1319 
  1320 * ZF: as above, for int: operators coerce their operands to an integer
  1321 using the function intify;
  1322 
  1323 * ZF: the integer library now contains many of the usual laws for the
  1324 orderings, including $<=, and monotonicity laws for $+ and $*;
  1325 
  1326 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1327 simplification;
  1328 
  1329 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1330 to the simplifier and classical reasoner simultaneously;
  1331 
  1332 
  1333 *** General ***
  1334 
  1335 * Provers: blast_tac now handles actual object-logic rules as
  1336 assumptions; note that auto_tac uses blast_tac internally as well;
  1337 
  1338 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1339 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1340 
  1341 * Provers: delrules now handles destruct rules as well (no longer need
  1342 explicit make_elim);
  1343 
  1344 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1345   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1346 use instead the strong form,
  1347   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1348 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1349 from destruct-rules;
  1350 
  1351 * Provers: Simplifier.easy_setup provides a fast path to basic
  1352 Simplifier setup for new object-logics;
  1353 
  1354 * Pure: AST translation rules no longer require constant head on LHS;
  1355 
  1356 * Pure: improved name spaces: ambiguous output is qualified; support
  1357 for hiding of names;
  1358 
  1359 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1360 XSYMBOL_HOME; no longer need to do manual configuration in most
  1361 situations;
  1362 
  1363 * system: compression of ML heaps images may now be controlled via -c
  1364 option of isabelle and isatool usedir (currently only observed by
  1365 Poly/ML);
  1366 
  1367 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1368 useful for remote X11);
  1369 
  1370 * system: provide TAGS file for Isabelle sources;
  1371 
  1372 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1373 order;
  1374 
  1375 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1376 timing flag supersedes proof_timing and Toplevel.trace;
  1377 
  1378 * ML: new combinators |>> and |>>> for incremental transformations
  1379 with secondary results (e.g. certain theory extensions):
  1380 
  1381 * ML: PureThy.add_defs gets additional argument to indicate potential
  1382 overloading (usually false);
  1383 
  1384 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1385 results;
  1386 
  1387 
  1388 
  1389 New in Isabelle99 (October 1999)
  1390 --------------------------------
  1391 
  1392 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1393 
  1394 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1395 are no longer simplified.  (This allows the simplifier to unfold recursive
  1396 functional programs.)  To restore the old behaviour, declare
  1397 
  1398     Delcongs [if_weak_cong];
  1399 
  1400 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1401 complement;
  1402 
  1403 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1404 
  1405 * HOL/datatype: mutual_induct_tac no longer exists --
  1406   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1407 
  1408 * HOL/typedef: fixed type inference for representing set; type
  1409 arguments now have to occur explicitly on the rhs as type constraints;
  1410 
  1411 * ZF: The con_defs part of an inductive definition may no longer refer
  1412 to constants declared in the same theory;
  1413 
  1414 * HOL, ZF: the function mk_cases, generated by the inductive
  1415 definition package, has lost an argument.  To simplify its result, it
  1416 uses the default simpset instead of a supplied list of theorems.
  1417 
  1418 * HOL/List: the constructors of type list are now Nil and Cons;
  1419 
  1420 * Simplifier: the type of the infix ML functions
  1421         setSSolver addSSolver setSolver addSolver
  1422 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1423 for packaging solvers. A solver is created via
  1424         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1425 where the string argument is only a comment.
  1426 
  1427 
  1428 *** Proof tools ***
  1429 
  1430 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1431 decision procedure for linear arithmetic. Currently it is used for
  1432 types `nat', `int', and `real' in HOL (see below); it can, should and
  1433 will be instantiated for other types and logics as well.
  1434 
  1435 * The simplifier now accepts rewrite rules with flexible heads, eg
  1436      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1437   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1438   matching.
  1439 
  1440 
  1441 *** General ***
  1442 
  1443 * New Isabelle/Isar subsystem provides an alternative to traditional
  1444 tactical theorem proving; together with the ProofGeneral/isar user
  1445 interface it offers an interactive environment for developing human
  1446 readable proof documents (Isar == Intelligible semi-automated
  1447 reasoning); for further information see isatool doc isar-ref,
  1448 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1449 
  1450 * improved and simplified presentation of theories: better HTML markup
  1451 (including colors), graph views in several sizes; isatool usedir now
  1452 provides a proper interface for user theories (via -P option); actual
  1453 document preparation based on (PDF)LaTeX is available as well (for
  1454 new-style theories only); see isatool doc system for more information;
  1455 
  1456 * native support for Proof General, both for classic Isabelle and
  1457 Isabelle/Isar;
  1458 
  1459 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1460 using the graph browser tool;
  1461 
  1462 * Isabelle manuals now also available as PDF;
  1463 
  1464 * theory loader rewritten from scratch (may not be fully
  1465 bug-compatible); old loadpath variable has been replaced by show_path,
  1466 add_path, del_path, reset_path functions; new operations such as
  1467 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1468 isatool doc ref);
  1469 
  1470 * improved isatool install: option -k creates KDE application icon,
  1471 option -p DIR installs standalone binaries;
  1472 
  1473 * added ML_PLATFORM setting (useful for cross-platform installations);
  1474 more robust handling of platform specific ML images for SML/NJ;
  1475 
  1476 * the settings environment is now statically scoped, i.e. it is never
  1477 created again in sub-processes invoked from isabelle, isatool, or
  1478 Isabelle;
  1479 
  1480 * path element specification '~~' refers to '$ISABELLE_HOME';
  1481 
  1482 * in locales, the "assumes" and "defines" parts may be omitted if
  1483 empty;
  1484 
  1485 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1486 long arrows);
  1487 
  1488 * new print_mode "HTML";
  1489 
  1490 * new flag show_tags controls display of tags of theorems (which are
  1491 basically just comments that may be attached by some tools);
  1492 
  1493 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1494 mode and goal output format:
  1495 
  1496 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1497 244c244
  1498 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1499 ---
  1500 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1501 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1502 181c181
  1503 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1504 ---
  1505 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1506 
  1507 * function bind_thms stores lists of theorems (cf. bind_thm);
  1508 
  1509 * new shorthand tactics ftac, eatac, datac, fatac;
  1510 
  1511 * qed (and friends) now accept "" as result name; in that case the
  1512 theorem is not stored, but proper checks and presentation of the
  1513 result still apply;
  1514 
  1515 * theorem database now also indexes constants "Trueprop", "all",
  1516 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1517 
  1518 
  1519 *** HOL ***
  1520 
  1521 ** HOL arithmetic **
  1522 
  1523 * There are now decision procedures for linear arithmetic over nat and
  1524 int:
  1525 
  1526 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1527 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1528 are treated as atomic; subformulae not involving type `nat' or `int'
  1529 are ignored; quantified subformulae are ignored unless they are
  1530 positive universal or negative existential. The tactic has to be
  1531 invoked by hand and can be a little bit slow. In particular, the
  1532 running time is exponential in the number of occurrences of `min' and
  1533 `max', and `-' on `nat'.
  1534 
  1535 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1536 (negated) (in)equalities among the premises and the conclusion into
  1537 account (i.e. no compound formulae) and does not know about `min' and
  1538 `max', and `-' on `nat'. It is fast and is used automatically by the
  1539 simplifier.
  1540 
  1541 NB: At the moment, these decision procedures do not cope with mixed
  1542 nat/int formulae where the two parts interact, such as `m < n ==>
  1543 int(m) < int(n)'.
  1544 
  1545 * HOL/Numeral provides a generic theory of numerals (encoded
  1546 efficiently as bit strings); setup for types nat/int/real is in place;
  1547 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1548 int, existing theories and proof scripts may require a few additional
  1549 type constraints;
  1550 
  1551 * integer division and remainder can now be performed on constant
  1552 arguments;
  1553 
  1554 * many properties of integer multiplication, division and remainder
  1555 are now available;
  1556 
  1557 * An interface to the Stanford Validity Checker (SVC) is available through the
  1558 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1559 are proved automatically.  SVC must be installed separately, and its results
  1560 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1561 invocation of the underlying oracle).  For SVC see
  1562   http://verify.stanford.edu/SVC
  1563 
  1564 * IsaMakefile: the HOL-Real target now builds an actual image;
  1565 
  1566 
  1567 ** HOL misc **
  1568 
  1569 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1570 (in Isabelle/Isar) -- by Gertrud Bauer;
  1571 
  1572 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1573 analysis for assembly languages with subtypes;
  1574 
  1575 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1576 -- avoids syntactic ambiguities and treats state, transition, and
  1577 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1578 changed syntax and (many) tactics;
  1579 
  1580 * HOL/inductive: Now also handles more general introduction rules such
  1581   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1582   theorems are now maintained within the theory (maintained via the
  1583   "mono" attribute);
  1584 
  1585 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1586   (using function types) such as
  1587 
  1588   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1589 
  1590 * HOL/record: record_simproc (part of the default simpset) takes care
  1591 of selectors applied to updated records; record_split_tac is no longer
  1592 part of the default claset; update_defs may now be removed from the
  1593 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1594 
  1595   claset_ref () := claset() addSWrapper record_split_wrapper;
  1596   Delsimprocs [record_simproc]
  1597 
  1598 * HOL/typedef: fixed type inference for representing set; type
  1599 arguments now have to occur explicitly on the rhs as type constraints;
  1600 
  1601 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1602 names rather than an ML expression;
  1603 
  1604 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1605 supplied later.  Program schemes can be defined, such as
  1606     "While B C s = (if B s then While B C (C s) else s)"
  1607 where the well-founded relation can be chosen after B and C have been given.
  1608 
  1609 * HOL/List: the constructors of type list are now Nil and Cons;
  1610 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1611 course, ML tools referring to List.list.op # etc. have to be adapted;
  1612 
  1613 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1614 disabled by default; run isabelle with option -m HOL to get back to
  1615 the original Gordon/HOL-style output;
  1616 
  1617 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1618 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1619 
  1620 * HOL basic syntax simplified (more orthogonal): all variants of
  1621 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1622 Eps operator is provided as well: "SOME x. P[x]";
  1623 
  1624 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1625 
  1626 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1627 thus available for user theories;
  1628 
  1629 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1630 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1631 time;
  1632 
  1633 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1634 several times and then mp;
  1635 
  1636 
  1637 *** LK ***
  1638 
  1639 * the notation <<...>> is now available as a notation for sequences of
  1640 formulas;
  1641 
  1642 * the simplifier is now installed
  1643 
  1644 * the axiom system has been generalized (thanks to Soren Heilmann)
  1645 
  1646 * the classical reasoner now has a default rule database
  1647 
  1648 
  1649 *** ZF ***
  1650 
  1651 * new primrec section allows primitive recursive functions to be given
  1652 directly (as in HOL) over datatypes and the natural numbers;
  1653 
  1654 * new tactics induct_tac and exhaust_tac for induction (or case
  1655 analysis) over datatypes and the natural numbers;
  1656 
  1657 * the datatype declaration of type T now defines the recursor T_rec;
  1658 
  1659 * simplification automatically does freeness reasoning for datatype
  1660 constructors;
  1661 
  1662 * automatic type-inference, with AddTCs command to insert new
  1663 type-checking rules;
  1664 
  1665 * datatype introduction rules are now added as Safe Introduction rules
  1666 to the claset;
  1667 
  1668 * the syntax "if P then x else y" is now available in addition to
  1669 if(P,x,y);
  1670 
  1671 
  1672 *** Internal programming interfaces ***
  1673 
  1674 * tuned simplifier trace output; new flag debug_simp;
  1675 
  1676 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1677 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1678 
  1679 * AxClass.axclass_tac lost the theory argument;
  1680 
  1681 * tuned current_goals_markers semantics: begin / end goal avoids
  1682 printing empty lines;
  1683 
  1684 * removed prs and prs_fn hook, which was broken because it did not
  1685 include \n in its semantics, forcing writeln to add one
  1686 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1687 string -> unit if you really want to output text without newline;
  1688 
  1689 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1690 plain output, interface builders may have to enable 'isabelle_font'
  1691 mode to get Isabelle font glyphs as before;
  1692 
  1693 * refined token_translation interface; INCOMPATIBILITY: output length
  1694 now of type real instead of int;
  1695 
  1696 * theory loader actions may be traced via new ThyInfo.add_hook
  1697 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1698 your own database of information attached to *whole* theories -- as
  1699 opposed to intra-theory data slots offered via TheoryDataFun;
  1700 
  1701 * proper handling of dangling sort hypotheses (at last!);
  1702 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1703 extra sort hypotheses that can be witnessed from the type signature;
  1704 the force_strip_shyps flag is gone, any remaining shyps are simply
  1705 left in the theorem (with a warning issued by strip_shyps_warning);
  1706 
  1707 
  1708 
  1709 New in Isabelle98-1 (October 1998)
  1710 ----------------------------------
  1711 
  1712 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1713 
  1714 * several changes of automated proof tools;
  1715 
  1716 * HOL: major changes to the inductive and datatype packages, including
  1717 some minor incompatibilities of theory syntax;
  1718 
  1719 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1720 called `inj_on';
  1721 
  1722 * HOL: removed duplicate thms in Arith:
  1723   less_imp_add_less  should be replaced by  trans_less_add1
  1724   le_imp_add_le      should be replaced by  trans_le_add1
  1725 
  1726 * HOL: unary minus is now overloaded (new type constraints may be
  1727 required);
  1728 
  1729 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1730 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1731 now taken as an integer constant.
  1732 
  1733 * Pure: ML function 'theory_of' renamed to 'theory';
  1734 
  1735 
  1736 *** Proof tools ***
  1737 
  1738 * Simplifier:
  1739   1. Asm_full_simp_tac is now more aggressive.
  1740      1. It will sometimes reorient premises if that increases their power to
  1741         simplify.
  1742      2. It does no longer proceed strictly from left to right but may also
  1743         rotate premises to achieve further simplification.
  1744      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1745      old Asm_full_simp_tac in that it does not rotate premises.
  1746   2. The simplifier now knows a little bit about nat-arithmetic.
  1747 
  1748 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1749 allows for selected deletion of wrappers, by introduction of names for
  1750 wrapper functionals.  This implies that addbefore, addSbefore,
  1751 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1752 and that adding two tactics with the same name overwrites the first
  1753 one (emitting a warning).
  1754   type wrapper = (int -> tactic) -> (int -> tactic)
  1755   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1756   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1757   delWrapper, delSWrapper: claset *  string            -> claset
  1758   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1759 
  1760 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1761 semantics; addbefore now affects only the unsafe part of step_tac
  1762 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1763 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1764 by Force_tac;
  1765 
  1766 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1767 compWrapper; added safe wrapper (and access functions for it);
  1768 
  1769 * HOL/split_all_tac is now much faster and fails if there is nothing
  1770 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1771 and the names of the automatically generated variables have changed.
  1772 split_all_tac has moved within claset() from unsafe wrappers to safe
  1773 wrappers, which means that !!-bound variables are split much more
  1774 aggressively, and safe_tac and clarify_tac now split such variables.
  1775 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1776 Note: the same holds for record_split_tac, which does the job of
  1777 split_all_tac for record fields.
  1778 
  1779 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1780 permanently to the default simpset using Addsplits just like
  1781 Addsimps. They can be removed via Delsplits just like
  1782 Delsimps. Lower-case versions are also available.
  1783 
  1784 * HOL/Simplifier: The rule split_if is now part of the default
  1785 simpset. This means that the simplifier will eliminate all occurrences
  1786 of if-then-else in the conclusion of a goal. To prevent this, you can
  1787 either remove split_if completely from the default simpset by
  1788 `Delsplits [split_if]' or remove it in a specific call of the
  1789 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1790 other case splitting rules to/from the default simpset: every datatype
  1791 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1792 t is the name of the datatype).
  1793 
  1794 * Classical reasoner / Simplifier combination: new force_tac (and
  1795 derivatives Force_tac, force) combines rewriting and classical
  1796 reasoning (and whatever other tools) similarly to auto_tac, but is
  1797 aimed to solve the given subgoal completely.
  1798 
  1799 
  1800 *** General ***
  1801 
  1802 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1803 and `goalw': the theory is no longer needed as an explicit argument -
  1804 the current theory context is used; assumptions are no longer returned
  1805 at the ML-level unless one of them starts with ==> or !!; it is
  1806 recommended to convert to these new commands using isatool fixgoal
  1807 (backup your sources first!);
  1808 
  1809 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1810 the current theory context, and 'theory' to lookup stored theories;
  1811 
  1812 * new theory section 'locale' for declaring constants, assumptions and
  1813 definitions that have local scope;
  1814 
  1815 * new theory section 'nonterminals' for purely syntactic types;
  1816 
  1817 * new theory section 'setup' for generic ML setup functions
  1818 (e.g. package initialization);
  1819 
  1820 * the distribution now includes Isabelle icons: see
  1821 lib/logo/isabelle-{small,tiny}.xpm;
  1822 
  1823 * isatool install - install binaries with absolute references to
  1824 ISABELLE_HOME/bin;
  1825 
  1826 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1827 
  1828 * print mode 'emacs' reserved for Isamode;
  1829 
  1830 * support multiple print (ast) translations per constant name;
  1831 
  1832 * theorems involving oracles are now printed with a suffixed [!];
  1833 
  1834 
  1835 *** HOL ***
  1836 
  1837 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1838 
  1839 * HOL/inductive package reorganized and improved: now supports mutual
  1840 definitions such as
  1841 
  1842   inductive EVEN ODD
  1843     intrs
  1844       null "0 : EVEN"
  1845       oddI "n : EVEN ==> Suc n : ODD"
  1846       evenI "n : ODD ==> Suc n : EVEN"
  1847 
  1848 new theorem list "elims" contains an elimination rule for each of the
  1849 recursive sets; inductive definitions now handle disjunctive premises
  1850 correctly (also ZF);
  1851 
  1852 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1853 "mutual_induct" no longer exists - the induction rule is always
  1854 contained in "induct";
  1855 
  1856 
  1857 * HOL/datatype package re-implemented and greatly improved: now
  1858 supports mutually recursive datatypes such as
  1859 
  1860   datatype
  1861     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1862             | SUM ('a aexp) ('a aexp)
  1863             | DIFF ('a aexp) ('a aexp)
  1864             | NUM 'a
  1865   and
  1866     'a bexp = LESS ('a aexp) ('a aexp)
  1867             | AND ('a bexp) ('a bexp)
  1868             | OR ('a bexp) ('a bexp)
  1869 
  1870 as well as indirectly recursive datatypes such as
  1871 
  1872   datatype
  1873     ('a, 'b) term = Var 'a
  1874                   | App 'b ((('a, 'b) term) list)
  1875 
  1876 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1877 induction on mutually / indirectly recursive datatypes.
  1878 
  1879 Primrec equations are now stored in theory and can be accessed via
  1880 <function_name>.simps.
  1881 
  1882 INCOMPATIBILITIES:
  1883 
  1884   - Theories using datatypes must now have theory Datatype as an
  1885     ancestor.
  1886   - The specific <typename>.induct_tac no longer exists - use the
  1887     generic induct_tac instead.
  1888   - natE has been renamed to nat.exhaust - use exhaust_tac
  1889     instead of res_inst_tac ... natE. Note that the variable
  1890     names in nat.exhaust differ from the names in natE, this
  1891     may cause some "fragile" proofs to fail.
  1892   - The theorems split_<typename>_case and split_<typename>_case_asm
  1893     have been renamed to <typename>.split and <typename>.split_asm.
  1894   - Since default sorts of type variables are now handled correctly,
  1895     some datatype definitions may have to be annotated with explicit
  1896     sort constraints.
  1897   - Primrec definitions no longer require function name and type
  1898     of recursive argument.
  1899 
  1900 Consider using isatool fixdatatype to adapt your theories and proof
  1901 scripts to the new package (backup your sources first!).
  1902 
  1903 
  1904 * HOL/record package: considerably improved implementation; now
  1905 includes concrete syntax for record types, terms, updates; theorems
  1906 for surjective pairing and splitting !!-bound record variables; proof
  1907 support is as follows:
  1908 
  1909   1) standard conversions (selectors or updates applied to record
  1910 constructor terms) are part of the standard simpset;
  1911 
  1912   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1913 made part of standard simpset and claset via addIffs;
  1914 
  1915   3) a tactic for record field splitting (record_split_tac) is part of
  1916 the standard claset (addSWrapper);
  1917 
  1918 To get a better idea about these rules you may retrieve them via
  1919 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1920 the name of your record type.
  1921 
  1922 The split tactic 3) conceptually simplifies by the following rule:
  1923 
  1924   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1925 
  1926 Thus any record variable that is bound by meta-all will automatically
  1927 blow up into some record constructor term, consequently the
  1928 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1929 solve record problems automatically.
  1930 
  1931 
  1932 * reorganized the main HOL image: HOL/Integ and String loaded by
  1933 default; theory Main includes everything;
  1934 
  1935 * automatic simplification of integer sums and comparisons, using cancellation;
  1936 
  1937 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1938 
  1939 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1940 
  1941 * many new identities for unions, intersections, set difference, etc.;
  1942 
  1943 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1944 called split_if, split_split, split_sum_case and split_nat_case (to go
  1945 with add/delsplits);
  1946 
  1947 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1948 (?x::unit) = (); this is made part of the default simpset, which COULD
  1949 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1950 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1951 unit_abs_eta_conv is added in order to counter the effect of
  1952 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1953 %u.f();
  1954 
  1955 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1956 makes more sense);
  1957 
  1958 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1959   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1960   disjointness reasoning but breaking a few old proofs.
  1961 
  1962 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1963 to 'converse' from 'inverse' (for compatibility with ZF and some
  1964 literature);
  1965 
  1966 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1967 the well-founded relation;
  1968 
  1969 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1970     Compl A.  The "Compl" syntax remains available as input syntax for this
  1971     release ONLY.
  1972 
  1973 * HOL/Update: new theory of function updates:
  1974     f(a:=b) == %x. if x=a then b else f x
  1975 may also be iterated as in f(a:=b,c:=d,...);
  1976 
  1977 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1978 
  1979 * HOL/List:
  1980   - new function list_update written xs[i:=v] that updates the i-th
  1981     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1982   - new function `upt' written [i..j(] which generates the list
  1983     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1984     bound write [i..j], which is a shorthand for [i..j+1(].
  1985   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1986 
  1987 * HOL/Arith:
  1988   - removed 'pred' (predecessor) function;
  1989   - generalized some theorems about n-1;
  1990   - many new laws about "div" and "mod";
  1991   - new laws about greatest common divisors (see theory ex/Primes);
  1992 
  1993 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1994 instead of "inverse";
  1995 
  1996 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1997   of the multiset ordering;
  1998 
  1999 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2000   (not included by default);
  2001 
  2002 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2003 
  2004 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2005   programs, i.e. different program variables may have different types.
  2006 
  2007 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2008   [previously, this check worked only if the rewrite rule was unconditional]
  2009   Now rew can involve either definitions or equalities (either == or =).
  2010 
  2011 
  2012 *** ZF ***
  2013 
  2014 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2015   only the theorems proved on ZF.ML;
  2016 
  2017 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2018   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2019   disjointness reasoning but breaking a few old proofs.
  2020 
  2021 * ZF/Update: new theory of function updates
  2022     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2023   may also be iterated as in f(a:=b,c:=d,...);
  2024 
  2025 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2026 
  2027 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2028   [previously, this check worked only if the rewrite rule was unconditional]
  2029   Now rew can involve either definitions or equalities (either == or =).
  2030 
  2031 * case_tac provided for compatibility with HOL
  2032     (like the old excluded_middle_tac, but with subgoals swapped)
  2033 
  2034 
  2035 *** Internal programming interfaces ***
  2036 
  2037 * Pure: several new basic modules made available for general use, see
  2038 also src/Pure/README;
  2039 
  2040 * improved the theory data mechanism to support encapsulation (data
  2041 kind name replaced by private Object.kind, acting as authorization
  2042 key); new type-safe user interface via functor TheoryDataFun; generic
  2043 print_data function becomes basically useless;
  2044 
  2045 * removed global_names compatibility flag -- all theory declarations
  2046 are qualified by default;
  2047 
  2048 * module Pure/Syntax now offers quote / antiquote translation
  2049 functions (useful for Hoare logic etc. with implicit dependencies);
  2050 see HOL/ex/Antiquote for an example use;
  2051 
  2052 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2053 cterm -> thm;
  2054 
  2055 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2056 subgoal;
  2057 
  2058 * Display.print_goals function moved to Locale.print_goals;
  2059 
  2060 * standard print function for goals supports current_goals_markers
  2061 variable for marking begin of proof, end of proof, start of goal; the
  2062 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2063 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2064 for example;
  2065 
  2066 
  2067 
  2068 New in Isabelle98 (January 1998)
  2069 --------------------------------
  2070 
  2071 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2072 
  2073 * changed lexical syntax of terms / types: dots made part of long
  2074 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2075 
  2076 * simpset (and claset) reference variable replaced by functions
  2077 simpset / simpset_ref;
  2078 
  2079 * no longer supports theory aliases (via merge) and non-trivial
  2080 implicit merge of thms' signatures;
  2081 
  2082 * most internal names of constants changed due to qualified names;
  2083 
  2084 * changed Pure/Sequence interface (see Pure/seq.ML);
  2085 
  2086 
  2087 *** General Changes ***
  2088 
  2089 * hierachically structured name spaces (for consts, types, axms, thms
  2090 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2091 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2092 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2093 long_names for fully qualified output names; NOTE: ML programs
  2094 (special tactics, packages etc.) referring to internal names may have
  2095 to be adapted to cope with fully qualified names; in case of severe
  2096 backward campatibility problems try setting 'global_names' at compile
  2097 time to have enrything declared within a flat name space; one may also
  2098 fine tune name declarations in theories via the 'global' and 'local'
  2099 section;
  2100 
  2101 * reimplemented the implicit simpset and claset using the new anytype
  2102 data filed in signatures; references simpset:simpset ref etc. are
  2103 replaced by functions simpset:unit->simpset and
  2104 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2105 to patch your ML files accordingly;
  2106 
  2107 * HTML output now includes theory graph data for display with Java
  2108 applet or isatool browser; data generated automatically via isatool
  2109 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2110 
  2111 * defs may now be conditional; improved rewrite_goals_tac to handle
  2112 conditional equations;
  2113 
  2114 * defs now admits additional type arguments, using TYPE('a) syntax;
  2115 
  2116 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2117 creates a new theory node; implicit merge of thms' signatures is
  2118 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2119 transfer:theory->thm->thm in (rare) cases;
  2120 
  2121 * improved handling of draft signatures / theories; draft thms (and
  2122 ctyps, cterms) are automatically promoted to real ones;
  2123 
  2124 * slightly changed interfaces for oracles: admit many per theory, named
  2125 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2126 
  2127 * print_goals: optional output of const types (set show_consts and
  2128 show_types);
  2129 
  2130 * improved output of warnings (###) and errors (***);
  2131 
  2132 * subgoal_tac displays a warning if the new subgoal has type variables;
  2133 
  2134 * removed old README and Makefiles;
  2135 
  2136 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2137 
  2138 * removed obsolete init_pps and init_database;
  2139 
  2140 * deleted the obsolete tactical STATE, which was declared by
  2141     fun STATE tacfun st = tacfun st st;
  2142 
  2143 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2144 (which abbreviates $HOME);
  2145 
  2146 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2147 use isatool fixseq to adapt your ML programs (this works for fully
  2148 qualified references to the Sequence structure only!);
  2149 
  2150 * use_thy no longer requires writable current directory; it always
  2151 reloads .ML *and* .thy file, if either one is out of date;
  2152 
  2153 
  2154 *** Classical Reasoner ***
  2155 
  2156 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2157 tactics that use classical reasoning to simplify a subgoal without
  2158 splitting it into several subgoals;
  2159 
  2160 * Safe_tac: like safe_tac but uses the default claset;
  2161 
  2162 
  2163 *** Simplifier ***
  2164 
  2165 * added simplification meta rules:
  2166     (asm_)(full_)simplify: simpset -> thm -> thm;
  2167 
  2168 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2169 logics (again);
  2170 
  2171 * added prems argument to simplification procedures;
  2172 
  2173 * HOL, FOL, ZF: added infix function `addsplits':
  2174   instead of `<simpset> setloop (split_tac <thms>)'
  2175   you can simply write `<simpset> addsplits <thms>'
  2176 
  2177 
  2178 *** Syntax ***
  2179 
  2180 * TYPE('a) syntax for type reflection terms;
  2181 
  2182 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2183 
  2184 * pretty printer: changed order of mixfix annotation preference (again!);
  2185 
  2186 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2187 
  2188 
  2189 *** HOL ***
  2190 
  2191 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2192   with `addloop' of the simplifier to faciliate case splitting in premises.
  2193 
  2194 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2195 
  2196 * HOL/Auth: new protocol proofs including some for the Internet
  2197   protocol TLS;
  2198 
  2199 * HOL/Map: new theory of `maps' a la VDM;
  2200 
  2201 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2202 cancelling out common nat summands from =, <, <= (in)equalities, or
  2203 differences; simplification procedures nat_cancel_factor for
  2204 cancelling common factor from =, <, <= (in)equalities over natural
  2205 sums; nat_cancel contains both kinds of procedures, it is installed by
  2206 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2207 
  2208 * HOL/simplifier: terms of the form
  2209   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2210   are rewritten to
  2211   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2212   and those of the form
  2213   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2214   are rewritten to
  2215   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2216 
  2217 * HOL/datatype
  2218   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2219 
  2220   P(t_case f1 ... fn x) =
  2221      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2222         ...
  2223        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2224      )
  2225 
  2226   and a theorem `split_t_case_asm' of the form
  2227 
  2228   P(t_case f1 ... fn x) =
  2229     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2230         ...
  2231        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2232      )
  2233   which can be added to a simpset via `addsplits'. The existing theorems
  2234   expand_list_case and expand_option_case have been renamed to
  2235   split_list_case and split_option_case.
  2236 
  2237 * HOL/Arithmetic:
  2238   - `pred n' is automatically converted to `n-1'.
  2239     Users are strongly encouraged not to use `pred' any longer,
  2240     because it will disappear altogether at some point.
  2241   - Users are strongly encouraged to write "0 < n" rather than
  2242     "n ~= 0". Theorems and proof tools have been modified towards this
  2243     `standard'.
  2244 
  2245 * HOL/Lists:
  2246   the function "set_of_list" has been renamed "set" (and its theorems too);
  2247   the function "nth" now takes its arguments in the reverse order and
  2248   has acquired the infix notation "!" as in "xs!n".
  2249 
  2250 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2251 
  2252 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2253   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2254 
  2255 * HOL/record: extensible records with schematic structural subtyping
  2256 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2257 still lacks various theorems and concrete record syntax;
  2258 
  2259 
  2260 *** HOLCF ***
  2261 
  2262 * removed "axioms" and "generated by" sections;
  2263 
  2264 * replaced "ops" section by extended "consts" section, which is capable of
  2265   handling the continuous function space "->" directly;
  2266 
  2267 * domain package:
  2268   . proves theorems immediately and stores them in the theory,
  2269   . creates hierachical name space,
  2270   . now uses normal mixfix annotations (instead of cinfix...),
  2271   . minor changes to some names and values (for consistency),
  2272   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2273   . separator between mutual domain defs: changed "," to "and",
  2274   . improved handling of sort constraints;  now they have to
  2275     appear on the left-hand side of the equations only;
  2276 
  2277 * fixed LAM <x,y,zs>.b syntax;
  2278 
  2279 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2280 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2281 
  2282 
  2283 *** FOL and ZF ***
  2284 
  2285 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2286   with `addloop' of the simplifier to faciliate case splitting in premises.
  2287 
  2288 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2289 in HOL, they strip ALL and --> from proved theorems;
  2290 
  2291 
  2292 
  2293 New in Isabelle94-8 (May 1997)
  2294 ------------------------------
  2295 
  2296 *** General Changes ***
  2297 
  2298 * new utilities to build / run / maintain Isabelle etc. (in parts
  2299 still somewhat experimental); old Makefiles etc. still functional;
  2300 
  2301 * new 'Isabelle System Manual';
  2302 
  2303 * INSTALL text, together with ./configure and ./build scripts;
  2304 
  2305 * reimplemented type inference for greater efficiency, better error
  2306 messages and clean internal interface;
  2307 
  2308 * prlim command for dealing with lots of subgoals (an easier way of
  2309 setting goals_limit);
  2310 
  2311 
  2312 *** Syntax ***
  2313 
  2314 * supports alternative (named) syntax tables (parser and pretty
  2315 printer); internal interface is provided by add_modesyntax(_i);
  2316 
  2317 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2318 be used in conjunction with the Isabelle symbol font; uses the
  2319 "symbols" syntax table;
  2320 
  2321 * added token_translation interface (may translate name tokens in
  2322 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2323 the current print_mode); IMPORTANT: user print translation functions
  2324 are responsible for marking newly introduced bounds
  2325 (Syntax.mark_boundT);
  2326 
  2327 * token translations for modes "xterm" and "xterm_color" that display
  2328 names in bold, underline etc. or colors (which requires a color
  2329 version of xterm);
  2330 
  2331 * infixes may now be declared with names independent of their syntax;
  2332 
  2333 * added typed_print_translation (like print_translation, but may
  2334 access type of constant);
  2335 
  2336 
  2337 *** Classical Reasoner ***
  2338 
  2339 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2340 some limitations.  Blast_tac...
  2341   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2342   + ignores elimination rules that don't have the correct format
  2343         (the conclusion MUST be a formula variable)
  2344   + ignores types, which can make HOL proofs fail
  2345   + rules must not require higher-order unification, e.g. apply_type in ZF
  2346     [message "Function Var's argument not a bound variable" relates to this]
  2347   + its proof strategy is more general but can actually be slower
  2348 
  2349 * substitution with equality assumptions no longer permutes other
  2350 assumptions;
  2351 
  2352 * minor changes in semantics of addafter (now called addaltern); renamed
  2353 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2354 (and access functions for it);
  2355 
  2356 * improved combination of classical reasoner and simplifier:
  2357   + functions for handling clasimpsets
  2358   + improvement of addss: now the simplifier is called _after_ the
  2359     safe steps.
  2360   + safe variant of addss called addSss: uses safe simplifications
  2361     _during_ the safe steps. It is more complete as it allows multiple
  2362     instantiations of unknowns (e.g. with slow_tac).
  2363 
  2364 *** Simplifier ***
  2365 
  2366 * added interface for simplification procedures (functions that
  2367 produce *proven* rewrite rules on the fly, depending on current
  2368 redex);
  2369 
  2370 * ordering on terms as parameter (used for ordered rewriting);
  2371 
  2372 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2373 
  2374 * the solver is now split into a safe and an unsafe part.
  2375 This should be invisible for the normal user, except that the
  2376 functions setsolver and addsolver have been renamed to setSolver and
  2377 addSolver; added safe_asm_full_simp_tac;
  2378 
  2379 
  2380 *** HOL ***
  2381 
  2382 * a generic induction tactic `induct_tac' which works for all datatypes and
  2383 also for type `nat';
  2384 
  2385 * a generic case distinction tactic `exhaust_tac' which works for all
  2386 datatypes and also for type `nat';
  2387 
  2388 * each datatype comes with a function `size';
  2389 
  2390 * patterns in case expressions allow tuple patterns as arguments to
  2391 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2392 
  2393 * primrec now also works with type nat;
  2394 
  2395 * recdef: a new declaration form, allows general recursive functions to be
  2396 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2397 
  2398 * the constant for negation has been renamed from "not" to "Not" to
  2399 harmonize with FOL, ZF, LK, etc.;
  2400 
  2401 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2402 infinite lists;
  2403 
  2404 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2405 
  2406 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2407 problems in commutative rings, using axiomatic type classes for + and *;
  2408 
  2409 * more examples in HOL/MiniML and HOL/Auth;
  2410 
  2411 * more default rewrite rules for quantifiers, union/intersection;
  2412 
  2413 * a new constant `arbitrary == @x.False';
  2414 
  2415 * HOLCF/IOA replaces old HOL/IOA;
  2416 
  2417 * HOLCF changes: derived all rules and arities
  2418   + axiomatic type classes instead of classes
  2419   + typedef instead of faking type definitions
  2420   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2421   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2422   + eliminated the types void, one, tr
  2423   + use unit lift and bool lift (with translations) instead of one and tr
  2424   + eliminated blift from Lift3.thy (use Def instead of blift)
  2425   all eliminated rules are derived as theorems --> no visible changes ;
  2426 
  2427 
  2428 *** ZF ***
  2429 
  2430 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2431 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2432 as ZF_cs addSIs [equalityI];
  2433 
  2434 
  2435 
  2436 New in Isabelle94-7 (November 96)
  2437 ---------------------------------
  2438 
  2439 * allowing negative levels (as offsets) in prlev and choplev;
  2440 
  2441 * super-linear speedup for large simplifications;
  2442 
  2443 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2444 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2445 FAIL); can suppress it using the command Delsimps (ex_simps @
  2446 all_simps); De Morgan laws are also now included, by default;
  2447 
  2448 * improved printing of ==>  :  ~:
  2449 
  2450 * new object-logic "Sequents" adds linear logic, while replacing LK
  2451 and Modal (thanks to Sara Kalvala);
  2452 
  2453 * HOL/Auth: correctness proofs for authentication protocols;
  2454 
  2455 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2456 examples on HOL/Auth);
  2457 
  2458 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2459 the rewriter and classical reasoner simultaneously;
  2460 
  2461 * function uresult no longer returns theorems in "standard" format;
  2462 regain previous version by: val uresult = standard o uresult;
  2463 
  2464 
  2465 
  2466 New in Isabelle94-6
  2467 -------------------
  2468 
  2469 * oracles -- these establish an interface between Isabelle and trusted
  2470 external reasoners, which may deliver results as theorems;
  2471 
  2472 * proof objects (in particular record all uses of oracles);
  2473 
  2474 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2475 
  2476 * "constdefs" section in theory files;
  2477 
  2478 * "primrec" section (HOL) no longer requires names;
  2479 
  2480 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2481 
  2482 
  2483 
  2484 New in Isabelle94-5
  2485 -------------------
  2486 
  2487 * reduced space requirements;
  2488 
  2489 * automatic HTML generation from theories;
  2490 
  2491 * theory files no longer require "..." (quotes) around most types;
  2492 
  2493 * new examples, including two proofs of the Church-Rosser theorem;
  2494 
  2495 * non-curried (1994) version of HOL is no longer distributed;
  2496 
  2497 
  2498 
  2499 New in Isabelle94-4
  2500 -------------------
  2501 
  2502 * greatly reduced space requirements;
  2503 
  2504 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2505 
  2506 * searchable theorem database (see the section "Retrieving theorems" on
  2507 page 8 of the Reference Manual);
  2508 
  2509 * new examples, including Grabczewski's monumental case study of the
  2510 Axiom of Choice;
  2511 
  2512 * The previous version of HOL renamed to Old_HOL;
  2513 
  2514 * The new version of HOL (previously called CHOL) uses a curried syntax
  2515 for functions.  Application looks like f a b instead of f(a,b);
  2516 
  2517 * Mutually recursive inductive definitions finally work in HOL;
  2518 
  2519 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2520 translates to the operator "split";
  2521 
  2522 
  2523 
  2524 New in Isabelle94-3
  2525 -------------------
  2526 
  2527 * new infix operator, addss, allowing the classical reasoner to
  2528 perform simplification at each step of its search.  Example:
  2529         fast_tac (cs addss ss)
  2530 
  2531 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2532 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2533 look like (a,b) instead of <a,b>;
  2534 
  2535 * PLEASE NOTE: CHOL will eventually replace HOL!
  2536 
  2537 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2538 It translates to the operator "split".  A new theory of integers is available;
  2539 
  2540 * In ZF, integer numerals now denote two's-complement binary integers.
  2541 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2542 
  2543 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2544 of the Axiom of Choice;
  2545 
  2546 
  2547 
  2548 New in Isabelle94-2
  2549 -------------------
  2550 
  2551 * Significantly faster resolution;
  2552 
  2553 * the different sections in a .thy file can now be mixed and repeated
  2554 freely;
  2555 
  2556 * Database of theorems for FOL, HOL and ZF.  New
  2557 commands including qed, qed_goal and bind_thm store theorems in the database.
  2558 
  2559 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2560 a given theory (thms_of), or find out what theory a theorem was proved in
  2561 (theory_of_thm);
  2562 
  2563 * Bugs fixed in the inductive definition and datatype packages;
  2564 
  2565 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2566 and HOL_dup_cs obsolete;
  2567 
  2568 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2569 have been removed;
  2570 
  2571 * Simpler definition of function space in ZF;
  2572 
  2573 * new results about cardinal and ordinal arithmetic in ZF;
  2574 
  2575 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2576 types;
  2577 
  2578 
  2579 $Id$