NEWS
author schirmer
Mon May 03 23:22:17 2004 +0200 (2004-05-03)
changeset 14700 2f885b7e5ba7
parent 14699 2c9b463044ec
child 14707 2d6350d7b9b7
permissions -rw-r--r--
reimplementation of HOL records; only one type is created for
each record extension, instead of one type for each field. See NEWS.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: considerably improved version of 'constdefs' command.  Now
    10 performs automatic type-inference of declared constants; additional
    11 support for local structure declarations (cf. locales and HOL
    12 records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    13 to observe strictly sequential dependencies of definitions within a
    14 single 'constdefs' section; moreover, the declared name needs to be an
    15 identifier.  If all fails, consider to fall back on 'consts' and
    16 'defs' separately.
    17 
    18 * Pure: 'advanced' translation functions (parse_translation etc.) may
    19 depend on the signature of the theory context being presently used for
    20 parsing/printing, see also isar-ref manual.
    21 
    22 
    23 * Pure: improved indexed syntax and implicit structures.  First of
    24 all, indexed syntax provides a notational device for subscripted
    25 application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    26 expressions.  Secondly, in a local context with structure
    27 declarations, number indexes \<^sub>n or the empty index (default
    28 number 1) refer to a certain fixed variable implicitly.  Typical
    29 applications of these concepts involve record types and locales.
    30 
    31 * Pure: tuned internal renaming of symbolic identifiers -- attach
    32 primes instead of base 26 numbers.
    33 
    34 *** HOL ***
    35 
    36 * Records:
    37    Reimplementation of records to avoid performance problems for
    38    type inference. Records are no longer composed of nested field types,
    39    but of nested extension types. Therefore the record type only grows
    40    linear in the number of extensions and not in the number of fields.
    41    The top-level (users) view on records is preserved. 
    42    Potential INCOMPATIBILITY only in strange cases, where the theory
    43    depends on the old record representation. The type generated for
    44    a record is called <record_name>_ext_type.    
    45 
    46 *** HOLCF ***
    47 
    48 * HOLCF: discontinued special version of 'constdefs' (which used to
    49 support continuous functions) in favor of the general Pure one with
    50 full type-inference.
    51 
    52 
    53 
    54 New in Isabelle2004 (April 2004)
    55 --------------------------------
    56 
    57 *** General ***
    58 
    59 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    60   Replaces linorder.ML.
    61 
    62 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
    63   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
    64   (\<a>...\<z>), are now considered normal letters, and can therefore
    65   be used anywhere where an ASCII letter (a...zA...Z) has until
    66   now. COMPATIBILITY: This obviously changes the parsing of some
    67   terms, especially where a symbol has been used as a binder, say
    68   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    69   as an identifier.  Fix it by inserting a space around former
    70   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    71   existing theory and ML files.
    72 
    73 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    74 
    75 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    76   allowed in identifiers. Similar to Greek letters \<^isub> is now considered 
    77   a normal (but invisible) letter. For multiple letter subscripts repeat 
    78   \<^isub> like this: x\<^isub>1\<^isub>2. 
    79 
    80 * Pure: There are now sub-/superscripts that can span more than one
    81   character. Text between \<^bsub> and \<^esub> is set in subscript in
    82   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
    83   superscript. The new control characters are not identifier parts.
    84 
    85 * Pure: Control-symbols of the form \<^raw:...> will literally print the
    86   content of "..." to the latex file instead of \isacntrl... . The "..."
    87   may consist of any printable characters excluding the end bracket >.
    88 
    89 * Pure: Using new Isar command "finalconsts" (or the ML functions
    90   Theory.add_finals or Theory.add_finals_i) it is now possible to
    91   declare constants "final", which prevents their being given a definition
    92   later.  It is useful for constants whose behaviour is fixed axiomatically
    93   rather than definitionally, such as the meta-logic connectives.
    94 
    95 * Pure: 'instance' now handles general arities with general sorts
    96   (i.e. intersections of classes),
    97 
    98 * Presentation: generated HTML now uses a CSS style sheet to make layout
    99   (somewhat) independent of content. It is copied from lib/html/isabelle.css. 
   100   It can be changed to alter the colors/layout of generated pages.
   101 
   102 
   103 *** Isar ***
   104 
   105 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   106   cut_tac, subgoal_tac and thin_tac:
   107   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   108     locales are no longer forced to write Isar proof scripts.
   109     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   110     emulations.
   111   - INCOMPATIBILITY: names of variables to be instantiated may no
   112     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   113     This is consistent with the instantiation attribute "where".
   114 
   115 * Attributes "where" and "of":
   116   - Now take type variables of instantiated theorem into account when reading
   117     the instantiation string.  This fixes a bug that caused instantiated
   118     theorems to have too special types in some circumstances.
   119   - "where" permits explicit instantiations of type variables.
   120 
   121 * Calculation commands "moreover" and "also" no longer interfere with
   122   current facts ("this"), admitting arbitrary combinations with "then"
   123   and derived forms.
   124 
   125 * Locales:
   126   - Goal statements involving the context element "includes" no longer
   127     generate theorems with internal delta predicates (those ending on
   128     "_axioms") in the premise.
   129     Resolve particular premise with <locale>.intro to obtain old form.
   130   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   131     specification and "includes" elements in goal statement.
   132   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   133     [intro?] and [elim?] (respectively) by default.
   134   - Experimental command for instantiation of locales in proof contexts:
   135         instantiate <label>[<attrs>]: <loc>
   136     Instantiates locale <loc> and adds all its theorems to the current context
   137     taking into account their attributes.  Label and attrs are optional
   138     modifiers, like in theorem declarations.  If present, names of
   139     instantiated theorems are qualified with <label>, and the attributes
   140     <attrs> are applied after any attributes these theorems might have already.
   141       If the locale has assumptions, a chained fact of the form
   142     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   143     are derived.  The command does not support old-style locales declared
   144     with "locale (open)".
   145       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   146 
   147 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   148   (Isar) contexts.
   149 
   150 
   151 *** HOL ***
   152 
   153 * Proof import: new image HOL4 contains the imported library from
   154   the HOL4 system with about 2500 theorems. It is imported by
   155   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   156   can be used like any other Isabelle image.  See
   157   HOL/Import/HOL/README for more information.
   158 
   159 * Simplifier:
   160   - Much improved handling of linear and partial orders.
   161     Reasoners for linear and partial orders are set up for type classes
   162     "linorder" and "order" respectively, and are added to the default simpset
   163     as solvers.  This means that the simplifier can build transitivity chains
   164     to solve goals from the assumptions.
   165   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   166     of blast or auto after simplification become unnecessary because the goal
   167     is solved by simplification already.
   168 
   169 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   170     all proved in axiomatic type classes for semirings, rings and fields.
   171 
   172 * Numerics:
   173   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   174     now formalized using the Ring_and_Field theory mentioned above. 
   175   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   176     than before, because now they are set up once in a generic manner.
   177   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   178     Look for the general versions in Ring_and_Field (and Power if they concern
   179     exponentiation).
   180 
   181 * Type "rat" of the rational numbers is now available in HOL-Complex.
   182 
   183 * Records:
   184   - Record types are now by default printed with their type abbreviation
   185     instead of the list of all field types. This can be configured via
   186     the reference "print_record_type_abbr".
   187   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   188     (not enabled by default).
   189   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   190     EX x. x = sel r to True (not enabled by default).
   191   - Tactic "record_split_simp_tac" to split and simplify records added.
   192  
   193 * 'specification' command added, allowing for definition by
   194   specification.  There is also an 'ax_specification' command that
   195   introduces the new constants axiomatically.
   196 
   197 * arith(_tac) is now able to generate counterexamples for reals as well.
   198 
   199 * HOL-Algebra: new locale "ring" for non-commutative rings.
   200 
   201 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   202   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   203 
   204 * HOL-Matrix: a first theory for matrices in HOL with an application of 
   205   matrix theory to linear programming.
   206 
   207 * Unions and Intersections:
   208   The x-symbol output syntax of UN and INT has been changed
   209   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   210   i.e. the index formulae has become a subscript, like in normal math.
   211   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   212   The subscript version is also accepted as input syntax.
   213 
   214 * Unions and Intersections over Intervals:
   215   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   216   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   217   like in normal math, and corresponding versions for < and for intersection.
   218 
   219 * ML: the legacy theory structures Int and List have been removed. They had
   220   conflicted with ML Basis Library structures having the same names.
   221 
   222 * 'refute' command added to search for (finite) countermodels.  Only works
   223   for a fragment of HOL.  The installation of an external SAT solver is
   224   highly recommended.  See "HOL/Refute.thy" for details.
   225 
   226 * 'quickcheck' command: Allows to find counterexamples by evaluating
   227   formulae under an assignment of free variables to random values.
   228   In contrast to 'refute', it can deal with inductive datatypes,
   229   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   230   for examples.
   231 
   232 
   233 *** HOLCF ***
   234 
   235 * Streams now come with concatenation and are part of the HOLCF image
   236 
   237 
   238 
   239 New in Isabelle2003 (May 2003)
   240 ------------------------------
   241 
   242 *** General ***
   243 
   244 * Provers/simplifier:
   245 
   246   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   247     Assumptions are now subject to complete mutual simplification,
   248     not just from left to right. The simplifier now preserves
   249     the order of assumptions.
   250 
   251     Potential INCOMPATIBILITY:
   252 
   253     -- simp sometimes diverges where the old version did
   254        not, e.g. invoking simp on the goal
   255 
   256         [| P (f x); y = x; f x = f y |] ==> Q
   257 
   258        now gives rise to the infinite reduction sequence
   259 
   260         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   261 
   262        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   263        kind of problem.
   264 
   265     -- Tactics combining classical reasoner and simplification (such as auto)
   266        are also affected by this change, because many of them rely on
   267        simp. They may sometimes diverge as well or yield a different numbers
   268        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   269        in case of problems. Sometimes subsequent calls to the classical
   270        reasoner will fail because a preceeding call to the simplifier too
   271        eagerly simplified the goal, e.g. deleted redundant premises.
   272 
   273   - The simplifier trace now shows the names of the applied rewrite rules
   274 
   275   - You can limit the number of recursive invocations of the simplifier
   276     during conditional rewriting (where the simplifie tries to solve the
   277     conditions before applying the rewrite rule):
   278     ML "simp_depth_limit := n"
   279     where n is an integer. Thus you can force termination where previously
   280     the simplifier would diverge.
   281 
   282   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   283 
   284   - No longer aborts on failed congruence proof.  Instead, the
   285     congruence is ignored.
   286 
   287 * Pure: New generic framework for extracting programs from constructive
   288   proofs. See HOL/Extraction.thy for an example instantiation, as well
   289   as HOL/Extraction for some case studies.
   290 
   291 * Pure: The main goal of the proof state is no longer shown by default, only
   292 the subgoals. This behaviour is controlled by a new flag.
   293    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   294 (ML: Proof.show_main_goal).
   295 
   296 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   297 rules whose conclusion matches subgoal 1:
   298       PG menu: Isabelle/Isar -> Show me -> matching rules
   299 The rules are ordered by how closely they match the subgoal.
   300 In particular, rules that solve a subgoal outright are displayed first
   301 (or rather last, the way they are printed).
   302 (ML: ProofGeneral.print_intros())
   303 
   304 * Pure: New flag trace_unify_fail causes unification to print
   305 diagnostic information (PG: in trace buffer) when it fails. This is
   306 useful for figuring out why single step proofs like rule, erule or
   307 assumption failed.
   308 
   309 * Pure: Locale specifications now produce predicate definitions
   310 according to the body of text (covering assumptions modulo local
   311 definitions); predicate "loc_axioms" covers newly introduced text,
   312 while "loc" is cumulative wrt. all included locale expressions; the
   313 latter view is presented only on export into the global theory
   314 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   315 on the old view without predicates;
   316 
   317 * Pure: predefined locales "var" and "struct" are useful for sharing
   318 parameters (as in CASL, for example); just specify something like
   319 ``var x + var y + struct M'' as import;
   320 
   321 * Pure: improved thms_containing: proper indexing of facts instead of
   322 raw theorems; check validity of results wrt. current name space;
   323 include local facts of proof configuration (also covers active
   324 locales), cover fixed variables in index; may use "_" in term
   325 specification; an optional limit for the number of printed facts may
   326 be given (the default is 40);
   327 
   328 * Pure: disallow duplicate fact bindings within new-style theory files
   329 (batch-mode only);
   330 
   331 * Provers: improved induct method: assumptions introduced by case
   332 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   333 the goal statement); "foo" still refers to all facts collectively;
   334 
   335 * Provers: the function blast.overloaded has been removed: all constants
   336 are regarded as potentially overloaded, which improves robustness in exchange
   337 for slight decrease in efficiency;
   338 
   339 * Provers/linorder: New generic prover for transitivity reasoning over
   340 linear orders.  Note: this prover is not efficient!
   341 
   342 * Isar: preview of problems to finish 'show' now produce an error
   343 rather than just a warning (in interactive mode);
   344 
   345 
   346 *** HOL ***
   347 
   348 * arith(_tac)
   349 
   350  - Produces a counter example if it cannot prove a goal.
   351    Note that the counter example may be spurious if the goal is not a formula
   352    of quantifier-free linear arithmetic.
   353    In ProofGeneral the counter example appears in the trace buffer.
   354 
   355  - Knows about div k and mod k where k is a numeral of type nat or int.
   356 
   357  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   358    linear arithmetic fails. This takes account of quantifiers and divisibility.
   359    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   360 
   361 * simp's arithmetic capabilities have been enhanced a bit: it now
   362 takes ~= in premises into account (by performing a case split);
   363 
   364 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   365 are distributed over a sum of terms;
   366 
   367 * New tactic "trans_tac" and method "trans" instantiate
   368 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   369 "<=", "<" and "="). 
   370 
   371 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   372 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   373 
   374 * 'typedef' command has new option "open" to suppress the set
   375 definition;
   376 
   377 * functions Min and Max on finite sets have been introduced (theory
   378 Finite_Set);
   379 
   380 * attribute [symmetric] now works for relations as well; it turns
   381 (x,y) : R^-1 into (y,x) : R, and vice versa;
   382 
   383 * induct over a !!-quantified statement (say !!x1..xn):
   384   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   385 
   386 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   387 %x. None. Warning: empty_def now refers to the previously hidden definition
   388 of the empty set.
   389 
   390 * Algebra: formalization of classical algebra.  Intended as base for
   391 any algebraic development in Isabelle.  Currently covers group theory
   392 (up to Sylow's theorem) and ring theory (Universal Property of
   393 Univariate Polynomials).  Contributions welcome;
   394 
   395 * GroupTheory: deleted, since its material has been moved to Algebra;
   396 
   397 * Complex: new directory of the complex numbers with numeric constants, 
   398 nonstandard complex numbers, and some complex analysis, standard and 
   399 nonstandard (Jacques Fleuriot);
   400 
   401 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   402 
   403 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   404 Fleuriot);
   405 
   406 * Real/HahnBanach: updated and adapted to locales;
   407 
   408 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   409 Gray and Kramer);
   410 
   411 * UNITY: added the Meier-Sanders theory of progress sets;
   412 
   413 * MicroJava: bytecode verifier and lightweight bytecode verifier
   414 as abstract algorithms, instantiated to the JVM;
   415 
   416 * Bali: Java source language formalization. Type system, operational
   417 semantics, axiomatic semantics. Supported language features:
   418 classes, interfaces, objects,virtual methods, static methods,
   419 static/instance fields, arrays, access modifiers, definite
   420 assignment, exceptions.
   421 
   422 
   423 *** ZF ***
   424 
   425 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   426 universe, etc.);
   427 
   428 * Main ZF: virtually all theories converted to new-style format;
   429 
   430 
   431 *** ML ***
   432 
   433 * Pure: Tactic.prove provides sane interface for internal proofs;
   434 omits the infamous "standard" operation, so this is more appropriate
   435 than prove_goalw_cterm in many situations (e.g. in simprocs);
   436 
   437 * Pure: improved error reporting of simprocs;
   438 
   439 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   440 up simprocs;
   441 
   442 
   443 *** Document preparation ***
   444 
   445 * uses \par instead of \\ for line breaks in theory text. This may
   446 shift some page breaks in large documents. To get the old behaviour
   447 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   448 
   449 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   450 other packages
   451 
   452 * \<euro> now needs package babel/greek instead of marvosym (which
   453 broke \Rightarrow)
   454 
   455 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   456 textcomp package)
   457 
   458 
   459 
   460 New in Isabelle2002 (March 2002)
   461 --------------------------------
   462 
   463 *** Document preparation ***
   464 
   465 * greatly simplified document preparation setup, including more
   466 graceful interpretation of isatool usedir -i/-d/-D options, and more
   467 instructive isatool mkdir; users should basically be able to get
   468 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   469 users may run a separate document processing stage manually like this:
   470 "isatool usedir -D output HOL Test && isatool document Test/output";
   471 
   472 * theory dependency graph may now be incorporated into documents;
   473 isatool usedir -g true will produce session_graph.eps/.pdf for use
   474 with \includegraphics of LaTeX;
   475 
   476 * proper spacing of consecutive markup elements, especially text
   477 blocks after section headings;
   478 
   479 * support bold style (for single symbols only), input syntax is like
   480 this: "\<^bold>\<alpha>" or "\<^bold>A";
   481 
   482 * \<bullet> is now output as bold \cdot by default, which looks much
   483 better in printed text;
   484 
   485 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   486 note that these symbols are currently unavailable in Proof General /
   487 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   488 
   489 * isatool latex no longer depends on changed TEXINPUTS, instead
   490 isatool document copies the Isabelle style files to the target
   491 location;
   492 
   493 
   494 *** Isar ***
   495 
   496 * Pure/Provers: improved proof by cases and induction;
   497   - 'case' command admits impromptu naming of parameters (such as
   498     "case (Suc n)");
   499   - 'induct' method divinates rule instantiation from the inductive
   500     claim; no longer requires excessive ?P bindings for proper
   501     instantiation of cases;
   502   - 'induct' method properly enumerates all possibilities of set/type
   503     rules; as a consequence facts may be also passed through *type*
   504     rules without further ado;
   505   - 'induct' method now derives symbolic cases from the *rulified*
   506     rule (before it used to rulify cases stemming from the internal
   507     atomized version); this means that the context of a non-atomic
   508     statement becomes is included in the hypothesis, avoiding the
   509     slightly cumbersome show "PROP ?case" form;
   510   - 'induct' may now use elim-style induction rules without chaining
   511     facts, using ``missing'' premises from the goal state; this allows
   512     rules stemming from inductive sets to be applied in unstructured
   513     scripts, while still benefitting from proper handling of non-atomic
   514     statements; NB: major inductive premises need to be put first, all
   515     the rest of the goal is passed through the induction;
   516   - 'induct' proper support for mutual induction involving non-atomic
   517     rule statements (uses the new concept of simultaneous goals, see
   518     below);
   519   - append all possible rule selections, but only use the first
   520     success (no backtracking);
   521   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   522   - undeclared rule case names default to numbers 1, 2, 3, ...;
   523   - added 'print_induct_rules' (covered by help item in recent Proof
   524     General versions);
   525   - moved induct/cases attributes to Pure, methods to Provers;
   526   - generic method setup instantiated for FOL and HOL;
   527 
   528 * Pure: support multiple simultaneous goal statements, for example
   529 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   530 meta-level mechanism, this acts as if several individual goals had
   531 been stated separately; in particular common proof methods need to be
   532 repeated in order to cover all claims; note that a single elimination
   533 step is *not* sufficient to establish the two conjunctions, so this
   534 fails:
   535 
   536   assume "A & B" then have A and B ..   (*".." fails*)
   537 
   538 better use "obtain" in situations as above; alternative refer to
   539 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   540 
   541 * Pure: proper integration with ``locales''; unlike the original
   542 version by Florian Kammüller, Isar locales package high-level proof
   543 contexts rather than raw logical ones (e.g. we admit to include
   544 attributes everywhere); operations on locales include merge and
   545 rename; support for implicit arguments (``structures''); simultaneous
   546 type-inference over imports and text; see also HOL/ex/Locales.thy for
   547 some examples;
   548 
   549 * Pure: the following commands have been ``localized'', supporting a
   550 target locale specification "(in name)": 'lemma', 'theorem',
   551 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   552 stored both within the locale and at the theory level (exported and
   553 qualified by the locale name);
   554 
   555 * Pure: theory goals may now be specified in ``long'' form, with
   556 ad-hoc contexts consisting of arbitrary locale elements. for example
   557 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   558 definitions may be given, too); the result is a meta-level rule with
   559 the context elements being discharged in the obvious way;
   560 
   561 * Pure: new proof command 'using' allows to augment currently used
   562 facts after a goal statement ('using' is syntactically analogous to
   563 'apply', but acts on the goal's facts only); this allows chained facts
   564 to be separated into parts given before and after a claim, as in
   565 ``from a and b have C using d and e <proof>'';
   566 
   567 * Pure: renamed "antecedent" case to "rule_context";
   568 
   569 * Pure: new 'judgment' command records explicit information about the
   570 object-logic embedding (used by several tools internally); no longer
   571 use hard-wired "Trueprop";
   572 
   573 * Pure: added 'corollary' command;
   574 
   575 * Pure: fixed 'token_translation' command;
   576 
   577 * Pure: removed obsolete 'exported' attribute;
   578 
   579 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   580 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   581 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   582 
   583 * Pure: method 'atomize' presents local goal premises as object-level
   584 statements (atomic meta-level propositions); setup controlled via
   585 rewrite rules declarations of 'atomize' attribute; example
   586 application: 'induct' method with proper rule statements in improper
   587 proof *scripts*;
   588 
   589 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   590 now consider the syntactic context of assumptions, giving a better
   591 chance to get type-inference of the arguments right (this is
   592 especially important for locales);
   593 
   594 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   595 mode;
   596 
   597 * Pure/obtain: the formal conclusion "thesis", being marked as
   598 ``internal'', may no longer be reference directly in the text;
   599 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   600 situations;
   601 
   602 * Pure: generic 'sym' attribute which declares a rule both as pure
   603 'elim?' and for the 'symmetric' operation;
   604 
   605 * Pure: marginal comments ``--'' may now occur just anywhere in the
   606 text; the fixed correlation with particular command syntax has been
   607 discontinued;
   608 
   609 * Pure: new method 'rules' is particularly well-suited for proof
   610 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   611 but often produces more compact proof terms with less detours;
   612 
   613 * Pure/Provers/classical: simplified integration with pure rule
   614 attributes and methods; the classical "intro?/elim?/dest?"
   615 declarations coincide with the pure ones; the "rule" method no longer
   616 includes classically swapped intros; "intro" and "elim" methods no
   617 longer pick rules from the context; also got rid of ML declarations
   618 AddXIs/AddXEs/AddXDs; all of this has some potential for
   619 INCOMPATIBILITY;
   620 
   621 * Provers/classical: attribute 'swapped' produces classical inversions
   622 of introduction rules;
   623 
   624 * Provers/simplifier: 'simplified' attribute may refer to explicit
   625 rules instead of full simplifier context; 'iff' attribute handles
   626 conditional rules;
   627 
   628 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   629 
   630 * HOL: 'recdef' now fails on unfinished automated proofs, use
   631 "(permissive)" option to recover old behavior;
   632 
   633 * HOL: 'inductive' no longer features separate (collective) attributes
   634 for 'intros' (was found too confusing);
   635 
   636 * HOL: properly declared induction rules less_induct and
   637 wf_induct_rule;
   638 
   639 
   640 *** HOL ***
   641 
   642 * HOL: moved over to sane numeral syntax; the new policy is as
   643 follows:
   644 
   645   - 0 and 1 are polymorphic constants, which are defined on any
   646   numeric type (nat, int, real etc.);
   647 
   648   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   649   binary representation internally;
   650 
   651   - type nat has special constructor Suc, and generally prefers Suc 0
   652   over 1::nat and Suc (Suc 0) over 2::nat;
   653 
   654 This change may cause significant problems of INCOMPATIBILITY; here
   655 are some hints on converting existing sources:
   656 
   657   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   658   entities, so expressions involving "-" (unary or binary minus) need
   659   to be spaced properly;
   660 
   661   - existing occurrences of "1" may need to be constraint "1::nat" or
   662   even replaced by Suc 0; similar for old "2";
   663 
   664   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   665 
   666   - remove all special provisions on numerals in proofs;
   667 
   668 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   669 representation (depends on bin_arith_simps in the default context);
   670 
   671 * HOL: symbolic syntax for x^2 (numeral 2);
   672 
   673 * HOL: the class of all HOL types is now called "type" rather than
   674 "term"; INCOMPATIBILITY, need to adapt references to this type class
   675 in axclass/classes, instance/arities, and (usually rare) occurrences
   676 in typings (of consts etc.); internally the class is called
   677 "HOL.type", ML programs should refer to HOLogic.typeS;
   678 
   679 * HOL/record package improvements:
   680   - new derived operations "fields" to build a partial record section,
   681     "extend" to promote a fixed record to a record scheme, and
   682     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   683     declared as simp by default;
   684   - shared operations ("more", "fields", etc.) now need to be always
   685     qualified) --- potential INCOMPATIBILITY;
   686   - removed "make_scheme" operations (use "make" with "extend") --
   687     INCOMPATIBILITY;
   688   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   689   - provides cases/induct rules for use with corresponding Isar
   690     methods (for concrete records, record schemes, concrete more
   691     parts, and schematic more parts -- in that order);
   692   - internal definitions directly based on a light-weight abstract
   693     theory of product types over typedef rather than datatype;
   694 
   695 * HOL: generic code generator for generating executable ML code from
   696 specifications; specific support for HOL constructs such as inductive
   697 datatypes and sets, as well as recursive functions; can be invoked
   698 via 'generate_code' theory section;
   699 
   700 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   701 
   702 * HOL: consolidated and renamed several theories.  In particular:
   703 	Ord.thy has been absorbed into HOL.thy
   704 	String.thy has been absorbed into List.thy
   705  
   706 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   707 (beware of argument permutation!);
   708 
   709 * HOL: linorder_less_split superseded by linorder_cases;
   710 
   711 * HOL/List: "nodups" renamed to "distinct";
   712 
   713 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   714 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   715   - Ex_def has changed, now need to use some_eq_ex
   716 
   717 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   718 in this (rare) case use:
   719 
   720   delSWrapper "split_all_tac"
   721   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   722 
   723 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   724 MAY FAIL;
   725 
   726 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   727 Isabelle's type classes, ^ on functions and relations has too general
   728 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   729 necessary to attach explicit type constraints;
   730 
   731 * HOL/Relation: the prefix name of the infix "O" has been changed from
   732 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   733 renamed accordingly (eg "compI" -> "rel_compI").
   734 
   735 * HOL: syntax translations now work properly with numerals and records
   736 expressions;
   737 
   738 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   739 of "lam" -- INCOMPATIBILITY;
   740 
   741 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   742 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   743 renamed "Product_Type.unit";
   744 
   745 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   746 
   747 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   748 the "cases" method);
   749 
   750 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   751 Florian Kammüller);
   752 
   753 * HOL/IMP: updated and converted to new-style theory format; several
   754 parts turned into readable document, with proper Isar proof texts and
   755 some explanations (by Gerwin Klein);
   756 
   757 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   758 
   759 * HOL-Hyperreal is now a logic image;
   760 
   761 
   762 *** HOLCF ***
   763 
   764 * Isar: consts/constdefs supports mixfix syntax for continuous
   765 operations;
   766 
   767 * Isar: domain package adapted to new-style theory format, e.g. see
   768 HOLCF/ex/Dnat.thy;
   769 
   770 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   771 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   772 lift.induct_tac, always use UU instead of Undef;
   773 
   774 * HOLCF/IMP: updated and converted to new-style theory;
   775 
   776 
   777 *** ZF ***
   778 
   779 * Isar: proper integration of logic-specific tools and packages,
   780 including theory commands '(co)inductive', '(co)datatype',
   781 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   782 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   783 
   784 * theory Main no longer includes AC; for the Axiom of Choice, base
   785 your theory on Main_ZFC;
   786 
   787 * the integer library now covers quotients and remainders, with many
   788 laws relating division to addition, multiplication, etc.;
   789 
   790 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   791 typeless version of the formalism;
   792 
   793 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   794 format;
   795 
   796 * ZF/Induct: new directory for examples of inductive definitions,
   797 including theory Multiset for multiset orderings; converted to
   798 new-style theory format;
   799 
   800 * ZF: many new theorems about lists, ordinals, etc.;
   801 
   802 
   803 *** General ***
   804 
   805 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   806 variable proof controls level of detail: 0 = no proofs (only oracle
   807 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   808 also ref manual for further ML interfaces;
   809 
   810 * Pure/axclass: removed obsolete ML interface
   811 goal_subclass/goal_arity;
   812 
   813 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   814 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   815 separate tokens, so expressions involving minus need to be spaced
   816 properly;
   817 
   818 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   819 rather than "infixl" or "infixr";
   820 
   821 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   822 sort constraint specifications in type inference; e.g. "x::_::foo"
   823 ensures that the type of "x" is of sort "foo" (but not necessarily a
   824 type variable);
   825 
   826 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   827 control output of nested => (types); the default behavior is
   828 "type_brackets";
   829 
   830 * Pure/syntax: builtin parse translation for "_constify" turns valued
   831 tokens into AST constants;
   832 
   833 * Pure/syntax: prefer later declarations of translations and print
   834 translation functions; potential INCOMPATIBILITY: need to reverse
   835 multiple declarations for same syntax element constant;
   836 
   837 * Pure/show_hyps reset by default (in accordance to existing Isar
   838 practice);
   839 
   840 * Provers/classical: renamed addaltern to addafter, addSaltern to
   841 addSafter;
   842 
   843 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   844 as well;
   845 
   846 * system: tested support for MacOS X; should be able to get Isabelle +
   847 Proof General to work in a plain Terminal after installing Poly/ML
   848 (e.g. from the Isabelle distribution area) and GNU bash alone
   849 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   850 support requires further installations, e.g. from
   851 http://fink.sourceforge.net/);
   852 
   853 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   854 
   855 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   856 of 40 MB), cf. ML_OPTIONS;
   857 
   858 * system: Proof General keywords specification is now part of the
   859 Isabelle distribution (see etc/isar-keywords.el);
   860 
   861 * system: support for persistent Proof General sessions (refrain from
   862 outdating all loaded theories on startup); user may create writable
   863 logic images like this: ``isabelle -q HOL Test'';
   864 
   865 * system: smart selection of Isabelle process versus Isabelle
   866 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   867 run both "isabelle" and "Isabelle" even if file names are badly
   868 damaged (executable inspects the case of the first letter of its own
   869 name); added separate "isabelle-process" and "isabelle-interface";
   870 
   871 * system: refrain from any attempt at filtering input streams; no
   872 longer support ``8bit'' encoding of old isabelle font, instead proper
   873 iso-latin characters may now be used; the related isatools
   874 "symbolinput" and "nonascii" have disappeared as well;
   875 
   876 * system: removed old "xterm" interface (the print modes "xterm" and
   877 "xterm_color" are still available for direct use in a suitable
   878 terminal);
   879 
   880 
   881 
   882 New in Isabelle99-2 (February 2001)
   883 -----------------------------------
   884 
   885 *** Overview of INCOMPATIBILITIES ***
   886 
   887 * HOL: please note that theories in the Library and elsewhere often use the
   888 new-style (Isar) format; to refer to their theorems in an ML script you must
   889 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   890 
   891 * HOL: inductive package no longer splits induction rule aggressively,
   892 but only as far as specified by the introductions given; the old
   893 format may be recovered via ML function complete_split_rule or attribute
   894 'split_rule (complete)';
   895 
   896 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   897 gfp_Tarski to gfp_unfold;
   898 
   899 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   900 
   901 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   902 relation); infix "^^" has been renamed "``"; infix "``" has been
   903 renamed "`"; "univalent" has been renamed "single_valued";
   904 
   905 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   906 operation;
   907 
   908 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   909 
   910 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   911 
   912 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   913 consequence, it is no longer monotonic wrt. the local goal context
   914 (which is now passed through the inductive cases);
   915 
   916 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   917 \<gg> to \<ggreater>;
   918 
   919 
   920 *** Document preparation ***
   921 
   922 * \isabellestyle{NAME} selects version of Isabelle output (currently
   923 available: are "it" for near math-mode best-style output, "sl" for
   924 slanted text style, and "tt" for plain type-writer; if no
   925 \isabellestyle command is given, output is according to slanted
   926 type-writer);
   927 
   928 * support sub/super scripts (for single symbols only), input syntax is
   929 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   930 
   931 * some more standard symbols; see Appendix A of the system manual for
   932 the complete list of symbols defined in isabellesym.sty;
   933 
   934 * improved isabelle style files; more abstract symbol implementation
   935 (should now use \isamath{...} and \isatext{...} in custom symbol
   936 definitions);
   937 
   938 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   939 state; Note that presentation of goal states does not conform to
   940 actual human-readable proof documents.  Please do not include goal
   941 states into document output unless you really know what you are doing!
   942 
   943 * proper indentation of antiquoted output with proportional LaTeX
   944 fonts;
   945 
   946 * no_document ML operator temporarily disables LaTeX document
   947 generation;
   948 
   949 * isatool unsymbolize tunes sources for plain ASCII communication;
   950 
   951 
   952 *** Isar ***
   953 
   954 * Pure: Isar now suffers initial goal statements to contain unbound
   955 schematic variables (this does not conform to actual readable proof
   956 documents, due to unpredictable outcome and non-compositional proof
   957 checking); users who know what they are doing may use schematic goals
   958 for Prolog-style synthesis of proven results;
   959 
   960 * Pure: assumption method (an implicit finishing) now handles actual
   961 rules as well;
   962 
   963 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   964 initial goal, declare "that" only as Pure intro (only for single
   965 steps); the "that" rule assumption may now be involved in implicit
   966 finishing, thus ".." becomes a feasible for trivial obtains;
   967 
   968 * Pure: default proof step now includes 'intro_classes'; thus trivial
   969 instance proofs may be performed by "..";
   970 
   971 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   972 statements as well;
   973 
   974 * Pure: more robust selection of calculational rules;
   975 
   976 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   977 rule (as well as the assumption rule);
   978 
   979 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   980 lemmas, using the graph browser tool;
   981 
   982 * Pure: predict failure of "show" in interactive mode;
   983 
   984 * Pure: 'thms_containing' now takes actual terms as arguments;
   985 
   986 * HOL: improved method 'induct' --- now handles non-atomic goals
   987 (potential INCOMPATIBILITY); tuned error handling;
   988 
   989 * HOL: cases and induct rules now provide explicit hints about the
   990 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   991 any remaining facts are inserted into the goal verbatim;
   992 
   993 * HOL: local contexts (aka cases) may now contain term bindings as
   994 well; the 'cases' and 'induct' methods new provide a ?case binding for
   995 the result to be shown in each case;
   996 
   997 * HOL: added 'recdef_tc' command;
   998 
   999 * isatool convert assists in eliminating legacy ML scripts;
  1000 
  1001 
  1002 *** HOL ***
  1003 
  1004 * HOL/Library: a collection of generic theories to be used together
  1005 with main HOL; the theory loader path already includes this directory
  1006 by default; the following existing theories have been moved here:
  1007 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1008 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1009 
  1010 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1011 modelling and verification task performed in Isabelle/HOL +
  1012 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1013 
  1014 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1015 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1016 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1017 'domain', this makes the theory consistent with mathematical
  1018 literature;
  1019 
  1020 * HOL basics: added overloaded operations "inverse" and "divide"
  1021 (infix "/"), syntax for generic "abs" operation, generic summation
  1022 operator \<Sum>;
  1023 
  1024 * HOL/typedef: simplified package, provide more useful rules (see also
  1025 HOL/subset.thy);
  1026 
  1027 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1028 now expressed as a proper nested rule (old-style tactic scripts may
  1029 require atomize_strip_tac to cope with non-atomic premises);
  1030 
  1031 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1032 to "split_conv" (old name still available for compatibility);
  1033 
  1034 * HOL: improved concrete syntax for strings (e.g. allows translation
  1035 rules with string literals);
  1036 
  1037 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1038  and Fleuriot's mechanization of analysis, including the transcendental
  1039  functions for the reals;
  1040 
  1041 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1042 
  1043 
  1044 *** CTT ***
  1045 
  1046 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1047 "lam" is displayed as TWO lambda-symbols
  1048 
  1049 * CTT: theory Main now available, containing everything (that is, Bool
  1050 and Arith);
  1051 
  1052 
  1053 *** General ***
  1054 
  1055 * Pure: the Simplifier has been implemented properly as a derived rule
  1056 outside of the actual kernel (at last!); the overall performance
  1057 penalty in practical applications is about 50%, while reliability of
  1058 the Isabelle inference kernel has been greatly improved;
  1059 
  1060 * print modes "brackets" and "no_brackets" control output of nested =>
  1061 (types) and ==> (props); the default behaviour is "brackets";
  1062 
  1063 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1064 as assumptions as well;
  1065 
  1066 * system: support Poly/ML 4.0;
  1067 
  1068 * system: isatool install handles KDE version 1 or 2;
  1069 
  1070 
  1071 
  1072 New in Isabelle99-1 (October 2000)
  1073 ----------------------------------
  1074 
  1075 *** Overview of INCOMPATIBILITIES ***
  1076 
  1077 * HOL: simplification of natural numbers is much changed; to partly
  1078 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1079 issue the following ML commands:
  1080 
  1081   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1082   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1083 
  1084 * HOL: simplification no longer dives into case-expressions; this is
  1085 controlled by "t.weak_case_cong" for each datatype t;
  1086 
  1087 * HOL: nat_less_induct renamed to less_induct;
  1088 
  1089 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1090 fixsome to patch .thy and .ML sources automatically;
  1091 
  1092   select_equality  -> some_equality
  1093   select_eq_Ex     -> some_eq_ex
  1094   selectI2EX       -> someI2_ex
  1095   selectI2         -> someI2
  1096   selectI          -> someI
  1097   select1_equality -> some1_equality
  1098   Eps_sym_eq       -> some_sym_eq_trivial
  1099   Eps_eq           -> some_eq_trivial
  1100 
  1101 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1102 
  1103 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1104 instead);
  1105 
  1106 * HOL: the recursion equations generated by 'recdef' are now called
  1107 f.simps instead of f.rules;
  1108 
  1109 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1110 
  1111 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1112 sometimes be needed;
  1113 
  1114 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1115 
  1116 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1117 
  1118 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1119 product is now "<*>" instead of "Times"; the lexicographic product is
  1120 now "<*lex*>" instead of "**";
  1121 
  1122 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1123 of main HOL, but was unused); better use HOL's datatype package;
  1124 
  1125 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1126 the old syntax may be recovered as follows:
  1127 
  1128   syntax (symbols)
  1129     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1130       (infixl "\\<oplus>" 100)
  1131 
  1132 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1133 
  1134 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1135 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1136 internally;
  1137 
  1138 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1139 changed from A/r to A//r;
  1140 
  1141 * ZF: new treatment of arithmetic (nat & int) may break some old
  1142 proofs;
  1143 
  1144 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1145 rulify -> rule_format, elimify -> elim_format, ...);
  1146 
  1147 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1148 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1149 should have to change intro!! to intro? only); replaced "delrule" by
  1150 "rule del";
  1151 
  1152 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1153 
  1154 * Provers: strengthened force_tac by using new first_best_tac;
  1155 
  1156 * LaTeX document preparation: several changes of isabelle.sty (see
  1157 lib/texinputs);
  1158 
  1159 
  1160 *** Document preparation ***
  1161 
  1162 * formal comments (text blocks etc.) in new-style theories may now
  1163 contain antiquotations of thm/prop/term/typ/text to be presented
  1164 according to latex print mode; concrete syntax is like this:
  1165 @{term[show_types] "f(x) = a + x"};
  1166 
  1167 * isatool mkdir provides easy setup of Isabelle session directories,
  1168 including proper document sources;
  1169 
  1170 * generated LaTeX sources are now deleted after successful run
  1171 (isatool document -c); may retain a copy somewhere else via -D option
  1172 of isatool usedir;
  1173 
  1174 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1175 style files, achieving self-contained LaTeX sources and simplifying
  1176 LaTeX debugging;
  1177 
  1178 * old-style theories now produce (crude) LaTeX output as well;
  1179 
  1180 * browser info session directories are now self-contained (may be put
  1181 on WWW server seperately); improved graphs of nested sessions; removed
  1182 graph for 'all sessions';
  1183 
  1184 * several improvements in isabelle style files; \isabellestyle{it}
  1185 produces fake math mode output; \isamarkupheader is now \section by
  1186 default; see lib/texinputs/isabelle.sty etc.;
  1187 
  1188 
  1189 *** Isar ***
  1190 
  1191 * Isar/Pure: local results and corresponding term bindings are now
  1192 subject to Hindley-Milner polymorphism (similar to ML); this
  1193 accommodates incremental type-inference very nicely;
  1194 
  1195 * Isar/Pure: new derived language element 'obtain' supports
  1196 generalized existence reasoning;
  1197 
  1198 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1199 support accumulation of results, without applying any rules yet;
  1200 useful to collect intermediate results without explicit name
  1201 references, and for use with transitivity rules with more than 2
  1202 premises;
  1203 
  1204 * Isar/Pure: scalable support for case-analysis type proofs: new
  1205 'case' language element refers to local contexts symbolically, as
  1206 produced by certain proof methods; internally, case names are attached
  1207 to theorems as "tags";
  1208 
  1209 * Isar/Pure: theory command 'hide' removes declarations from
  1210 class/type/const name spaces;
  1211 
  1212 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1213 indicate potential overloading;
  1214 
  1215 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1216 
  1217 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1218 "{a,b,c}" instead of {a,b,c};
  1219 
  1220 * Isar/Pure now provides its own version of intro/elim/dest
  1221 attributes; useful for building new logics, but beware of confusion
  1222 with the version in Provers/classical;
  1223 
  1224 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1225 case name 'antecedent';
  1226 
  1227 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1228 to the current context is now done automatically);
  1229 
  1230 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1231 for definining proof methods in ML;
  1232 
  1233 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1234 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1235 most cases, one should have to change intro!! to intro? only);
  1236 replaced "delrule" by "rule del";
  1237 
  1238 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1239 'symmetric' attribute (the latter supercedes [RS sym]);
  1240 
  1241 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1242 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1243 well (including splits);
  1244 
  1245 * Isar/Provers: Simplifier and Classical methods now support all kind
  1246 of modifiers used in the past, including 'cong', 'iff', etc.
  1247 
  1248 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1249 of Simplifier and Classical reasoner);
  1250 
  1251 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1252 now support named cases; major packages (inductive, datatype, primrec,
  1253 recdef) support case names and properly name parameters;
  1254 
  1255 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1256 monotonicity conditions are extracted to be proven at end of
  1257 calculations;
  1258 
  1259 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1260 method anyway;
  1261 
  1262 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1263 split_if split_if_asm; datatype package provides theorems foo.splits =
  1264 foo.split foo.split_asm for each datatype;
  1265 
  1266 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1267 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1268 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1269 use "(cases (simplified))" method in proper proof texts);
  1270 
  1271 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1272 
  1273 * Isar: names of theorems etc. may be natural numbers as well;
  1274 
  1275 * Isar: 'pr' command: optional arguments for goals_limit and
  1276 ProofContext.prems_limit; no longer prints theory contexts, but only
  1277 proof states;
  1278 
  1279 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1280 additional print modes to be specified; e.g. "pr(latex)" will print
  1281 proof state according to the Isabelle LaTeX style;
  1282 
  1283 * Isar: improved support for emulating tactic scripts, including proof
  1284 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1285 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1286 (for HOL datatypes);
  1287 
  1288 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1289 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1290 'proof method scripts' have to be in depth-first order;
  1291 
  1292 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1293 
  1294 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1295 should instead use individual commands for printing items
  1296 (print_commands, print_methods etc.);
  1297 
  1298 * Isar: added 'nothing' --- the empty list of theorems;
  1299 
  1300 
  1301 *** HOL ***
  1302 
  1303 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1304 corresponding virtual machine and a specification of its bytecode
  1305 verifier and a lightweight bytecode verifier, including proofs of
  1306 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1307 Cornelia Pusch (see also the homepage of project Bali at
  1308 http://isabelle.in.tum.de/Bali/);
  1309 
  1310 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1311 Clemens Ballarin;
  1312 
  1313 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1314 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1315 Rasmussen;
  1316 
  1317 * HOL/Lattice: fundamental concepts of lattice theory and order
  1318 structures, including duals, properties of bounds versus algebraic
  1319 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1320 Theorem for complete lattices etc.; may also serve as a demonstration
  1321 for abstract algebraic reasoning using axiomatic type classes, and
  1322 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1323 
  1324 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1325 von Oheimb;
  1326 
  1327 * HOL/IMPP: extension of IMP with local variables and mutually
  1328 recursive procedures, by David von Oheimb;
  1329 
  1330 * HOL/Lambda: converted into new-style theory and document;
  1331 
  1332 * HOL/ex/Multiquote: example of multiple nested quotations and
  1333 anti-quotations -- basically a generalized version of de-Bruijn
  1334 representation; very useful in avoiding lifting of operations;
  1335 
  1336 * HOL/record: added general record equality rule to simpset; fixed
  1337 select-update simplification procedure to handle extended records as
  1338 well; admit "r" as field name;
  1339 
  1340 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1341 other numeric types and also as the identity of groups, rings, etc.;
  1342 
  1343 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1344 Types nat and int belong to this axclass;
  1345 
  1346 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1347    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1348    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1349   two terms #m*u and #n*u are replaced by #(m+n)*u
  1350     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1351   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1352     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1353 
  1354 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1355 powerful prover for predicate logic but knows nothing of clasets; see
  1356 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1357 
  1358 * HOL: new version of "case_tac" subsumes both boolean case split and
  1359 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1360 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1361 
  1362 * HOL: simplification no longer dives into case-expressions: only the
  1363 selector expression is simplified, but not the remaining arms; to
  1364 enable full simplification of case-expressions for datatype t, you may
  1365 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1366 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1367 
  1368 * HOL/recdef: the recursion equations generated by 'recdef' for
  1369 function 'f' are now called f.simps instead of f.rules; if all
  1370 termination conditions are proved automatically, these simplification
  1371 rules are added to the simpset, as in primrec; rules may be named
  1372 individually as well, resulting in a separate list of theorems for
  1373 each equation;
  1374 
  1375 * HOL/While is a new theory that provides a while-combinator. It
  1376 permits the definition of tail-recursive functions without the
  1377 provision of a termination measure. The latter is necessary once the
  1378 invariant proof rule for while is applied.
  1379 
  1380 * HOL: new (overloaded) notation for the set of elements below/above
  1381 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1382 
  1383 * HOL: theorems impI, allI, ballI bound as "strip";
  1384 
  1385 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1386 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1387 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1388 
  1389 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1390 
  1391 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1392 main HOL, but was unused);
  1393 
  1394 * HOL: fewer consts declared as global (e.g. have to refer to
  1395 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1396 
  1397 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1398 in case of overlap with user translations (e.g. judgements over
  1399 tuples); (note that the underlying logical represenation is still
  1400 bogus);
  1401 
  1402 
  1403 *** ZF ***
  1404 
  1405 * ZF: simplification automatically cancels common terms in arithmetic
  1406 expressions over nat and int;
  1407 
  1408 * ZF: new treatment of nat to minimize type-checking: all operators
  1409 coerce their operands to a natural number using the function natify,
  1410 making the algebraic laws unconditional;
  1411 
  1412 * ZF: as above, for int: operators coerce their operands to an integer
  1413 using the function intify;
  1414 
  1415 * ZF: the integer library now contains many of the usual laws for the
  1416 orderings, including $<=, and monotonicity laws for $+ and $*;
  1417 
  1418 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1419 simplification;
  1420 
  1421 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1422 to the simplifier and classical reasoner simultaneously;
  1423 
  1424 
  1425 *** General ***
  1426 
  1427 * Provers: blast_tac now handles actual object-logic rules as
  1428 assumptions; note that auto_tac uses blast_tac internally as well;
  1429 
  1430 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1431 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1432 
  1433 * Provers: delrules now handles destruct rules as well (no longer need
  1434 explicit make_elim);
  1435 
  1436 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1437   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1438 use instead the strong form,
  1439   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1440 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1441 from destruct-rules;
  1442 
  1443 * Provers: Simplifier.easy_setup provides a fast path to basic
  1444 Simplifier setup for new object-logics;
  1445 
  1446 * Pure: AST translation rules no longer require constant head on LHS;
  1447 
  1448 * Pure: improved name spaces: ambiguous output is qualified; support
  1449 for hiding of names;
  1450 
  1451 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1452 XSYMBOL_HOME; no longer need to do manual configuration in most
  1453 situations;
  1454 
  1455 * system: compression of ML heaps images may now be controlled via -c
  1456 option of isabelle and isatool usedir (currently only observed by
  1457 Poly/ML);
  1458 
  1459 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1460 useful for remote X11);
  1461 
  1462 * system: provide TAGS file for Isabelle sources;
  1463 
  1464 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1465 order;
  1466 
  1467 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1468 timing flag supersedes proof_timing and Toplevel.trace;
  1469 
  1470 * ML: new combinators |>> and |>>> for incremental transformations
  1471 with secondary results (e.g. certain theory extensions):
  1472 
  1473 * ML: PureThy.add_defs gets additional argument to indicate potential
  1474 overloading (usually false);
  1475 
  1476 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1477 results;
  1478 
  1479 
  1480 
  1481 New in Isabelle99 (October 1999)
  1482 --------------------------------
  1483 
  1484 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1485 
  1486 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1487 are no longer simplified.  (This allows the simplifier to unfold recursive
  1488 functional programs.)  To restore the old behaviour, declare
  1489 
  1490     Delcongs [if_weak_cong];
  1491 
  1492 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1493 complement;
  1494 
  1495 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1496 
  1497 * HOL/datatype: mutual_induct_tac no longer exists --
  1498   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1499 
  1500 * HOL/typedef: fixed type inference for representing set; type
  1501 arguments now have to occur explicitly on the rhs as type constraints;
  1502 
  1503 * ZF: The con_defs part of an inductive definition may no longer refer
  1504 to constants declared in the same theory;
  1505 
  1506 * HOL, ZF: the function mk_cases, generated by the inductive
  1507 definition package, has lost an argument.  To simplify its result, it
  1508 uses the default simpset instead of a supplied list of theorems.
  1509 
  1510 * HOL/List: the constructors of type list are now Nil and Cons;
  1511 
  1512 * Simplifier: the type of the infix ML functions
  1513         setSSolver addSSolver setSolver addSolver
  1514 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1515 for packaging solvers. A solver is created via
  1516         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1517 where the string argument is only a comment.
  1518 
  1519 
  1520 *** Proof tools ***
  1521 
  1522 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1523 decision procedure for linear arithmetic. Currently it is used for
  1524 types `nat', `int', and `real' in HOL (see below); it can, should and
  1525 will be instantiated for other types and logics as well.
  1526 
  1527 * The simplifier now accepts rewrite rules with flexible heads, eg
  1528      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1529   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1530   matching.
  1531 
  1532 
  1533 *** General ***
  1534 
  1535 * New Isabelle/Isar subsystem provides an alternative to traditional
  1536 tactical theorem proving; together with the ProofGeneral/isar user
  1537 interface it offers an interactive environment for developing human
  1538 readable proof documents (Isar == Intelligible semi-automated
  1539 reasoning); for further information see isatool doc isar-ref,
  1540 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1541 
  1542 * improved and simplified presentation of theories: better HTML markup
  1543 (including colors), graph views in several sizes; isatool usedir now
  1544 provides a proper interface for user theories (via -P option); actual
  1545 document preparation based on (PDF)LaTeX is available as well (for
  1546 new-style theories only); see isatool doc system for more information;
  1547 
  1548 * native support for Proof General, both for classic Isabelle and
  1549 Isabelle/Isar;
  1550 
  1551 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1552 using the graph browser tool;
  1553 
  1554 * Isabelle manuals now also available as PDF;
  1555 
  1556 * theory loader rewritten from scratch (may not be fully
  1557 bug-compatible); old loadpath variable has been replaced by show_path,
  1558 add_path, del_path, reset_path functions; new operations such as
  1559 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1560 isatool doc ref);
  1561 
  1562 * improved isatool install: option -k creates KDE application icon,
  1563 option -p DIR installs standalone binaries;
  1564 
  1565 * added ML_PLATFORM setting (useful for cross-platform installations);
  1566 more robust handling of platform specific ML images for SML/NJ;
  1567 
  1568 * the settings environment is now statically scoped, i.e. it is never
  1569 created again in sub-processes invoked from isabelle, isatool, or
  1570 Isabelle;
  1571 
  1572 * path element specification '~~' refers to '$ISABELLE_HOME';
  1573 
  1574 * in locales, the "assumes" and "defines" parts may be omitted if
  1575 empty;
  1576 
  1577 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1578 long arrows);
  1579 
  1580 * new print_mode "HTML";
  1581 
  1582 * new flag show_tags controls display of tags of theorems (which are
  1583 basically just comments that may be attached by some tools);
  1584 
  1585 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1586 mode and goal output format:
  1587 
  1588 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1589 244c244
  1590 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1591 ---
  1592 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1593 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1594 181c181
  1595 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1596 ---
  1597 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1598 
  1599 * function bind_thms stores lists of theorems (cf. bind_thm);
  1600 
  1601 * new shorthand tactics ftac, eatac, datac, fatac;
  1602 
  1603 * qed (and friends) now accept "" as result name; in that case the
  1604 theorem is not stored, but proper checks and presentation of the
  1605 result still apply;
  1606 
  1607 * theorem database now also indexes constants "Trueprop", "all",
  1608 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1609 
  1610 
  1611 *** HOL ***
  1612 
  1613 ** HOL arithmetic **
  1614 
  1615 * There are now decision procedures for linear arithmetic over nat and
  1616 int:
  1617 
  1618 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1619 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1620 are treated as atomic; subformulae not involving type `nat' or `int'
  1621 are ignored; quantified subformulae are ignored unless they are
  1622 positive universal or negative existential. The tactic has to be
  1623 invoked by hand and can be a little bit slow. In particular, the
  1624 running time is exponential in the number of occurrences of `min' and
  1625 `max', and `-' on `nat'.
  1626 
  1627 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1628 (negated) (in)equalities among the premises and the conclusion into
  1629 account (i.e. no compound formulae) and does not know about `min' and
  1630 `max', and `-' on `nat'. It is fast and is used automatically by the
  1631 simplifier.
  1632 
  1633 NB: At the moment, these decision procedures do not cope with mixed
  1634 nat/int formulae where the two parts interact, such as `m < n ==>
  1635 int(m) < int(n)'.
  1636 
  1637 * HOL/Numeral provides a generic theory of numerals (encoded
  1638 efficiently as bit strings); setup for types nat/int/real is in place;
  1639 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1640 int, existing theories and proof scripts may require a few additional
  1641 type constraints;
  1642 
  1643 * integer division and remainder can now be performed on constant
  1644 arguments;
  1645 
  1646 * many properties of integer multiplication, division and remainder
  1647 are now available;
  1648 
  1649 * An interface to the Stanford Validity Checker (SVC) is available through the
  1650 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1651 are proved automatically.  SVC must be installed separately, and its results
  1652 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1653 invocation of the underlying oracle).  For SVC see
  1654   http://verify.stanford.edu/SVC
  1655 
  1656 * IsaMakefile: the HOL-Real target now builds an actual image;
  1657 
  1658 
  1659 ** HOL misc **
  1660 
  1661 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1662 (in Isabelle/Isar) -- by Gertrud Bauer;
  1663 
  1664 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1665 analysis for assembly languages with subtypes;
  1666 
  1667 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1668 -- avoids syntactic ambiguities and treats state, transition, and
  1669 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1670 changed syntax and (many) tactics;
  1671 
  1672 * HOL/inductive: Now also handles more general introduction rules such
  1673   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1674   theorems are now maintained within the theory (maintained via the
  1675   "mono" attribute);
  1676 
  1677 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1678   (using function types) such as
  1679 
  1680   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1681 
  1682 * HOL/record: record_simproc (part of the default simpset) takes care
  1683 of selectors applied to updated records; record_split_tac is no longer
  1684 part of the default claset; update_defs may now be removed from the
  1685 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1686 
  1687   claset_ref () := claset() addSWrapper record_split_wrapper;
  1688   Delsimprocs [record_simproc]
  1689 
  1690 * HOL/typedef: fixed type inference for representing set; type
  1691 arguments now have to occur explicitly on the rhs as type constraints;
  1692 
  1693 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1694 names rather than an ML expression;
  1695 
  1696 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1697 supplied later.  Program schemes can be defined, such as
  1698     "While B C s = (if B s then While B C (C s) else s)"
  1699 where the well-founded relation can be chosen after B and C have been given.
  1700 
  1701 * HOL/List: the constructors of type list are now Nil and Cons;
  1702 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1703 course, ML tools referring to List.list.op # etc. have to be adapted;
  1704 
  1705 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1706 disabled by default; run isabelle with option -m HOL to get back to
  1707 the original Gordon/HOL-style output;
  1708 
  1709 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1710 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1711 
  1712 * HOL basic syntax simplified (more orthogonal): all variants of
  1713 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1714 Eps operator is provided as well: "SOME x. P[x]";
  1715 
  1716 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1717 
  1718 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1719 thus available for user theories;
  1720 
  1721 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1722 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1723 time;
  1724 
  1725 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1726 several times and then mp;
  1727 
  1728 
  1729 *** LK ***
  1730 
  1731 * the notation <<...>> is now available as a notation for sequences of
  1732 formulas;
  1733 
  1734 * the simplifier is now installed
  1735 
  1736 * the axiom system has been generalized (thanks to Soren Heilmann)
  1737 
  1738 * the classical reasoner now has a default rule database
  1739 
  1740 
  1741 *** ZF ***
  1742 
  1743 * new primrec section allows primitive recursive functions to be given
  1744 directly (as in HOL) over datatypes and the natural numbers;
  1745 
  1746 * new tactics induct_tac and exhaust_tac for induction (or case
  1747 analysis) over datatypes and the natural numbers;
  1748 
  1749 * the datatype declaration of type T now defines the recursor T_rec;
  1750 
  1751 * simplification automatically does freeness reasoning for datatype
  1752 constructors;
  1753 
  1754 * automatic type-inference, with AddTCs command to insert new
  1755 type-checking rules;
  1756 
  1757 * datatype introduction rules are now added as Safe Introduction rules
  1758 to the claset;
  1759 
  1760 * the syntax "if P then x else y" is now available in addition to
  1761 if(P,x,y);
  1762 
  1763 
  1764 *** Internal programming interfaces ***
  1765 
  1766 * tuned simplifier trace output; new flag debug_simp;
  1767 
  1768 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1769 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1770 
  1771 * AxClass.axclass_tac lost the theory argument;
  1772 
  1773 * tuned current_goals_markers semantics: begin / end goal avoids
  1774 printing empty lines;
  1775 
  1776 * removed prs and prs_fn hook, which was broken because it did not
  1777 include \n in its semantics, forcing writeln to add one
  1778 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1779 string -> unit if you really want to output text without newline;
  1780 
  1781 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1782 plain output, interface builders may have to enable 'isabelle_font'
  1783 mode to get Isabelle font glyphs as before;
  1784 
  1785 * refined token_translation interface; INCOMPATIBILITY: output length
  1786 now of type real instead of int;
  1787 
  1788 * theory loader actions may be traced via new ThyInfo.add_hook
  1789 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1790 your own database of information attached to *whole* theories -- as
  1791 opposed to intra-theory data slots offered via TheoryDataFun;
  1792 
  1793 * proper handling of dangling sort hypotheses (at last!);
  1794 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1795 extra sort hypotheses that can be witnessed from the type signature;
  1796 the force_strip_shyps flag is gone, any remaining shyps are simply
  1797 left in the theorem (with a warning issued by strip_shyps_warning);
  1798 
  1799 
  1800 
  1801 New in Isabelle98-1 (October 1998)
  1802 ----------------------------------
  1803 
  1804 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1805 
  1806 * several changes of automated proof tools;
  1807 
  1808 * HOL: major changes to the inductive and datatype packages, including
  1809 some minor incompatibilities of theory syntax;
  1810 
  1811 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1812 called `inj_on';
  1813 
  1814 * HOL: removed duplicate thms in Arith:
  1815   less_imp_add_less  should be replaced by  trans_less_add1
  1816   le_imp_add_le      should be replaced by  trans_le_add1
  1817 
  1818 * HOL: unary minus is now overloaded (new type constraints may be
  1819 required);
  1820 
  1821 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1822 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1823 now taken as an integer constant.
  1824 
  1825 * Pure: ML function 'theory_of' renamed to 'theory';
  1826 
  1827 
  1828 *** Proof tools ***
  1829 
  1830 * Simplifier:
  1831   1. Asm_full_simp_tac is now more aggressive.
  1832      1. It will sometimes reorient premises if that increases their power to
  1833         simplify.
  1834      2. It does no longer proceed strictly from left to right but may also
  1835         rotate premises to achieve further simplification.
  1836      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1837      old Asm_full_simp_tac in that it does not rotate premises.
  1838   2. The simplifier now knows a little bit about nat-arithmetic.
  1839 
  1840 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1841 allows for selected deletion of wrappers, by introduction of names for
  1842 wrapper functionals.  This implies that addbefore, addSbefore,
  1843 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1844 and that adding two tactics with the same name overwrites the first
  1845 one (emitting a warning).
  1846   type wrapper = (int -> tactic) -> (int -> tactic)
  1847   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1848   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1849   delWrapper, delSWrapper: claset *  string            -> claset
  1850   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1851 
  1852 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1853 semantics; addbefore now affects only the unsafe part of step_tac
  1854 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1855 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1856 by Force_tac;
  1857 
  1858 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1859 compWrapper; added safe wrapper (and access functions for it);
  1860 
  1861 * HOL/split_all_tac is now much faster and fails if there is nothing
  1862 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1863 and the names of the automatically generated variables have changed.
  1864 split_all_tac has moved within claset() from unsafe wrappers to safe
  1865 wrappers, which means that !!-bound variables are split much more
  1866 aggressively, and safe_tac and clarify_tac now split such variables.
  1867 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1868 Note: the same holds for record_split_tac, which does the job of
  1869 split_all_tac for record fields.
  1870 
  1871 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1872 permanently to the default simpset using Addsplits just like
  1873 Addsimps. They can be removed via Delsplits just like
  1874 Delsimps. Lower-case versions are also available.
  1875 
  1876 * HOL/Simplifier: The rule split_if is now part of the default
  1877 simpset. This means that the simplifier will eliminate all occurrences
  1878 of if-then-else in the conclusion of a goal. To prevent this, you can
  1879 either remove split_if completely from the default simpset by
  1880 `Delsplits [split_if]' or remove it in a specific call of the
  1881 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1882 other case splitting rules to/from the default simpset: every datatype
  1883 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1884 t is the name of the datatype).
  1885 
  1886 * Classical reasoner / Simplifier combination: new force_tac (and
  1887 derivatives Force_tac, force) combines rewriting and classical
  1888 reasoning (and whatever other tools) similarly to auto_tac, but is
  1889 aimed to solve the given subgoal completely.
  1890 
  1891 
  1892 *** General ***
  1893 
  1894 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1895 and `goalw': the theory is no longer needed as an explicit argument -
  1896 the current theory context is used; assumptions are no longer returned
  1897 at the ML-level unless one of them starts with ==> or !!; it is
  1898 recommended to convert to these new commands using isatool fixgoal
  1899 (backup your sources first!);
  1900 
  1901 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1902 the current theory context, and 'theory' to lookup stored theories;
  1903 
  1904 * new theory section 'locale' for declaring constants, assumptions and
  1905 definitions that have local scope;
  1906 
  1907 * new theory section 'nonterminals' for purely syntactic types;
  1908 
  1909 * new theory section 'setup' for generic ML setup functions
  1910 (e.g. package initialization);
  1911 
  1912 * the distribution now includes Isabelle icons: see
  1913 lib/logo/isabelle-{small,tiny}.xpm;
  1914 
  1915 * isatool install - install binaries with absolute references to
  1916 ISABELLE_HOME/bin;
  1917 
  1918 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1919 
  1920 * print mode 'emacs' reserved for Isamode;
  1921 
  1922 * support multiple print (ast) translations per constant name;
  1923 
  1924 * theorems involving oracles are now printed with a suffixed [!];
  1925 
  1926 
  1927 *** HOL ***
  1928 
  1929 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1930 
  1931 * HOL/inductive package reorganized and improved: now supports mutual
  1932 definitions such as
  1933 
  1934   inductive EVEN ODD
  1935     intrs
  1936       null "0 : EVEN"
  1937       oddI "n : EVEN ==> Suc n : ODD"
  1938       evenI "n : ODD ==> Suc n : EVEN"
  1939 
  1940 new theorem list "elims" contains an elimination rule for each of the
  1941 recursive sets; inductive definitions now handle disjunctive premises
  1942 correctly (also ZF);
  1943 
  1944 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1945 "mutual_induct" no longer exists - the induction rule is always
  1946 contained in "induct";
  1947 
  1948 
  1949 * HOL/datatype package re-implemented and greatly improved: now
  1950 supports mutually recursive datatypes such as
  1951 
  1952   datatype
  1953     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1954             | SUM ('a aexp) ('a aexp)
  1955             | DIFF ('a aexp) ('a aexp)
  1956             | NUM 'a
  1957   and
  1958     'a bexp = LESS ('a aexp) ('a aexp)
  1959             | AND ('a bexp) ('a bexp)
  1960             | OR ('a bexp) ('a bexp)
  1961 
  1962 as well as indirectly recursive datatypes such as
  1963 
  1964   datatype
  1965     ('a, 'b) term = Var 'a
  1966                   | App 'b ((('a, 'b) term) list)
  1967 
  1968 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1969 induction on mutually / indirectly recursive datatypes.
  1970 
  1971 Primrec equations are now stored in theory and can be accessed via
  1972 <function_name>.simps.
  1973 
  1974 INCOMPATIBILITIES:
  1975 
  1976   - Theories using datatypes must now have theory Datatype as an
  1977     ancestor.
  1978   - The specific <typename>.induct_tac no longer exists - use the
  1979     generic induct_tac instead.
  1980   - natE has been renamed to nat.exhaust - use exhaust_tac
  1981     instead of res_inst_tac ... natE. Note that the variable
  1982     names in nat.exhaust differ from the names in natE, this
  1983     may cause some "fragile" proofs to fail.
  1984   - The theorems split_<typename>_case and split_<typename>_case_asm
  1985     have been renamed to <typename>.split and <typename>.split_asm.
  1986   - Since default sorts of type variables are now handled correctly,
  1987     some datatype definitions may have to be annotated with explicit
  1988     sort constraints.
  1989   - Primrec definitions no longer require function name and type
  1990     of recursive argument.
  1991 
  1992 Consider using isatool fixdatatype to adapt your theories and proof
  1993 scripts to the new package (backup your sources first!).
  1994 
  1995 
  1996 * HOL/record package: considerably improved implementation; now
  1997 includes concrete syntax for record types, terms, updates; theorems
  1998 for surjective pairing and splitting !!-bound record variables; proof
  1999 support is as follows:
  2000 
  2001   1) standard conversions (selectors or updates applied to record
  2002 constructor terms) are part of the standard simpset;
  2003 
  2004   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2005 made part of standard simpset and claset via addIffs;
  2006 
  2007   3) a tactic for record field splitting (record_split_tac) is part of
  2008 the standard claset (addSWrapper);
  2009 
  2010 To get a better idea about these rules you may retrieve them via
  2011 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2012 the name of your record type.
  2013 
  2014 The split tactic 3) conceptually simplifies by the following rule:
  2015 
  2016   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2017 
  2018 Thus any record variable that is bound by meta-all will automatically
  2019 blow up into some record constructor term, consequently the
  2020 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2021 solve record problems automatically.
  2022 
  2023 
  2024 * reorganized the main HOL image: HOL/Integ and String loaded by
  2025 default; theory Main includes everything;
  2026 
  2027 * automatic simplification of integer sums and comparisons, using cancellation;
  2028 
  2029 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2030 
  2031 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2032 
  2033 * many new identities for unions, intersections, set difference, etc.;
  2034 
  2035 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2036 called split_if, split_split, split_sum_case and split_nat_case (to go
  2037 with add/delsplits);
  2038 
  2039 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2040 (?x::unit) = (); this is made part of the default simpset, which COULD
  2041 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2042 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2043 unit_abs_eta_conv is added in order to counter the effect of
  2044 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2045 %u.f();
  2046 
  2047 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2048 makes more sense);
  2049 
  2050 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2051   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2052   disjointness reasoning but breaking a few old proofs.
  2053 
  2054 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2055 to 'converse' from 'inverse' (for compatibility with ZF and some
  2056 literature);
  2057 
  2058 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2059 the well-founded relation;
  2060 
  2061 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2062     Compl A.  The "Compl" syntax remains available as input syntax for this
  2063     release ONLY.
  2064 
  2065 * HOL/Update: new theory of function updates:
  2066     f(a:=b) == %x. if x=a then b else f x
  2067 may also be iterated as in f(a:=b,c:=d,...);
  2068 
  2069 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2070 
  2071 * HOL/List:
  2072   - new function list_update written xs[i:=v] that updates the i-th
  2073     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2074   - new function `upt' written [i..j(] which generates the list
  2075     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2076     bound write [i..j], which is a shorthand for [i..j+1(].
  2077   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2078 
  2079 * HOL/Arith:
  2080   - removed 'pred' (predecessor) function;
  2081   - generalized some theorems about n-1;
  2082   - many new laws about "div" and "mod";
  2083   - new laws about greatest common divisors (see theory ex/Primes);
  2084 
  2085 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2086 instead of "inverse";
  2087 
  2088 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2089   of the multiset ordering;
  2090 
  2091 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2092   (not included by default);
  2093 
  2094 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2095 
  2096 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2097   programs, i.e. different program variables may have different types.
  2098 
  2099 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2100   [previously, this check worked only if the rewrite rule was unconditional]
  2101   Now rew can involve either definitions or equalities (either == or =).
  2102 
  2103 
  2104 *** ZF ***
  2105 
  2106 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2107   only the theorems proved on ZF.ML;
  2108 
  2109 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2110   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2111   disjointness reasoning but breaking a few old proofs.
  2112 
  2113 * ZF/Update: new theory of function updates
  2114     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2115   may also be iterated as in f(a:=b,c:=d,...);
  2116 
  2117 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2118 
  2119 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2120   [previously, this check worked only if the rewrite rule was unconditional]
  2121   Now rew can involve either definitions or equalities (either == or =).
  2122 
  2123 * case_tac provided for compatibility with HOL
  2124     (like the old excluded_middle_tac, but with subgoals swapped)
  2125 
  2126 
  2127 *** Internal programming interfaces ***
  2128 
  2129 * Pure: several new basic modules made available for general use, see
  2130 also src/Pure/README;
  2131 
  2132 * improved the theory data mechanism to support encapsulation (data
  2133 kind name replaced by private Object.kind, acting as authorization
  2134 key); new type-safe user interface via functor TheoryDataFun; generic
  2135 print_data function becomes basically useless;
  2136 
  2137 * removed global_names compatibility flag -- all theory declarations
  2138 are qualified by default;
  2139 
  2140 * module Pure/Syntax now offers quote / antiquote translation
  2141 functions (useful for Hoare logic etc. with implicit dependencies);
  2142 see HOL/ex/Antiquote for an example use;
  2143 
  2144 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2145 cterm -> thm;
  2146 
  2147 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2148 subgoal;
  2149 
  2150 * Display.print_goals function moved to Locale.print_goals;
  2151 
  2152 * standard print function for goals supports current_goals_markers
  2153 variable for marking begin of proof, end of proof, start of goal; the
  2154 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2155 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2156 for example;
  2157 
  2158 
  2159 
  2160 New in Isabelle98 (January 1998)
  2161 --------------------------------
  2162 
  2163 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2164 
  2165 * changed lexical syntax of terms / types: dots made part of long
  2166 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2167 
  2168 * simpset (and claset) reference variable replaced by functions
  2169 simpset / simpset_ref;
  2170 
  2171 * no longer supports theory aliases (via merge) and non-trivial
  2172 implicit merge of thms' signatures;
  2173 
  2174 * most internal names of constants changed due to qualified names;
  2175 
  2176 * changed Pure/Sequence interface (see Pure/seq.ML);
  2177 
  2178 
  2179 *** General Changes ***
  2180 
  2181 * hierachically structured name spaces (for consts, types, axms, thms
  2182 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2183 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2184 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2185 long_names for fully qualified output names; NOTE: ML programs
  2186 (special tactics, packages etc.) referring to internal names may have
  2187 to be adapted to cope with fully qualified names; in case of severe
  2188 backward campatibility problems try setting 'global_names' at compile
  2189 time to have enrything declared within a flat name space; one may also
  2190 fine tune name declarations in theories via the 'global' and 'local'
  2191 section;
  2192 
  2193 * reimplemented the implicit simpset and claset using the new anytype
  2194 data filed in signatures; references simpset:simpset ref etc. are
  2195 replaced by functions simpset:unit->simpset and
  2196 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2197 to patch your ML files accordingly;
  2198 
  2199 * HTML output now includes theory graph data for display with Java
  2200 applet or isatool browser; data generated automatically via isatool
  2201 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2202 
  2203 * defs may now be conditional; improved rewrite_goals_tac to handle
  2204 conditional equations;
  2205 
  2206 * defs now admits additional type arguments, using TYPE('a) syntax;
  2207 
  2208 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2209 creates a new theory node; implicit merge of thms' signatures is
  2210 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2211 transfer:theory->thm->thm in (rare) cases;
  2212 
  2213 * improved handling of draft signatures / theories; draft thms (and
  2214 ctyps, cterms) are automatically promoted to real ones;
  2215 
  2216 * slightly changed interfaces for oracles: admit many per theory, named
  2217 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2218 
  2219 * print_goals: optional output of const types (set show_consts and
  2220 show_types);
  2221 
  2222 * improved output of warnings (###) and errors (***);
  2223 
  2224 * subgoal_tac displays a warning if the new subgoal has type variables;
  2225 
  2226 * removed old README and Makefiles;
  2227 
  2228 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2229 
  2230 * removed obsolete init_pps and init_database;
  2231 
  2232 * deleted the obsolete tactical STATE, which was declared by
  2233     fun STATE tacfun st = tacfun st st;
  2234 
  2235 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2236 (which abbreviates $HOME);
  2237 
  2238 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2239 use isatool fixseq to adapt your ML programs (this works for fully
  2240 qualified references to the Sequence structure only!);
  2241 
  2242 * use_thy no longer requires writable current directory; it always
  2243 reloads .ML *and* .thy file, if either one is out of date;
  2244 
  2245 
  2246 *** Classical Reasoner ***
  2247 
  2248 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2249 tactics that use classical reasoning to simplify a subgoal without
  2250 splitting it into several subgoals;
  2251 
  2252 * Safe_tac: like safe_tac but uses the default claset;
  2253 
  2254 
  2255 *** Simplifier ***
  2256 
  2257 * added simplification meta rules:
  2258     (asm_)(full_)simplify: simpset -> thm -> thm;
  2259 
  2260 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2261 logics (again);
  2262 
  2263 * added prems argument to simplification procedures;
  2264 
  2265 * HOL, FOL, ZF: added infix function `addsplits':
  2266   instead of `<simpset> setloop (split_tac <thms>)'
  2267   you can simply write `<simpset> addsplits <thms>'
  2268 
  2269 
  2270 *** Syntax ***
  2271 
  2272 * TYPE('a) syntax for type reflection terms;
  2273 
  2274 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2275 
  2276 * pretty printer: changed order of mixfix annotation preference (again!);
  2277 
  2278 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2279 
  2280 
  2281 *** HOL ***
  2282 
  2283 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2284   with `addloop' of the simplifier to faciliate case splitting in premises.
  2285 
  2286 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2287 
  2288 * HOL/Auth: new protocol proofs including some for the Internet
  2289   protocol TLS;
  2290 
  2291 * HOL/Map: new theory of `maps' a la VDM;
  2292 
  2293 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2294 cancelling out common nat summands from =, <, <= (in)equalities, or
  2295 differences; simplification procedures nat_cancel_factor for
  2296 cancelling common factor from =, <, <= (in)equalities over natural
  2297 sums; nat_cancel contains both kinds of procedures, it is installed by
  2298 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2299 
  2300 * HOL/simplifier: terms of the form
  2301   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2302   are rewritten to
  2303   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2304   and those of the form
  2305   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2306   are rewritten to
  2307   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2308 
  2309 * HOL/datatype
  2310   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2311 
  2312   P(t_case f1 ... fn x) =
  2313      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2314         ...
  2315        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2316      )
  2317 
  2318   and a theorem `split_t_case_asm' of the form
  2319 
  2320   P(t_case f1 ... fn x) =
  2321     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2322         ...
  2323        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2324      )
  2325   which can be added to a simpset via `addsplits'. The existing theorems
  2326   expand_list_case and expand_option_case have been renamed to
  2327   split_list_case and split_option_case.
  2328 
  2329 * HOL/Arithmetic:
  2330   - `pred n' is automatically converted to `n-1'.
  2331     Users are strongly encouraged not to use `pred' any longer,
  2332     because it will disappear altogether at some point.
  2333   - Users are strongly encouraged to write "0 < n" rather than
  2334     "n ~= 0". Theorems and proof tools have been modified towards this
  2335     `standard'.
  2336 
  2337 * HOL/Lists:
  2338   the function "set_of_list" has been renamed "set" (and its theorems too);
  2339   the function "nth" now takes its arguments in the reverse order and
  2340   has acquired the infix notation "!" as in "xs!n".
  2341 
  2342 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2343 
  2344 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2345   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2346 
  2347 * HOL/record: extensible records with schematic structural subtyping
  2348 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2349 still lacks various theorems and concrete record syntax;
  2350 
  2351 
  2352 *** HOLCF ***
  2353 
  2354 * removed "axioms" and "generated by" sections;
  2355 
  2356 * replaced "ops" section by extended "consts" section, which is capable of
  2357   handling the continuous function space "->" directly;
  2358 
  2359 * domain package:
  2360   . proves theorems immediately and stores them in the theory,
  2361   . creates hierachical name space,
  2362   . now uses normal mixfix annotations (instead of cinfix...),
  2363   . minor changes to some names and values (for consistency),
  2364   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2365   . separator between mutual domain defs: changed "," to "and",
  2366   . improved handling of sort constraints;  now they have to
  2367     appear on the left-hand side of the equations only;
  2368 
  2369 * fixed LAM <x,y,zs>.b syntax;
  2370 
  2371 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2372 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2373 
  2374 
  2375 *** FOL and ZF ***
  2376 
  2377 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2378   with `addloop' of the simplifier to faciliate case splitting in premises.
  2379 
  2380 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2381 in HOL, they strip ALL and --> from proved theorems;
  2382 
  2383 
  2384 
  2385 New in Isabelle94-8 (May 1997)
  2386 ------------------------------
  2387 
  2388 *** General Changes ***
  2389 
  2390 * new utilities to build / run / maintain Isabelle etc. (in parts
  2391 still somewhat experimental); old Makefiles etc. still functional;
  2392 
  2393 * new 'Isabelle System Manual';
  2394 
  2395 * INSTALL text, together with ./configure and ./build scripts;
  2396 
  2397 * reimplemented type inference for greater efficiency, better error
  2398 messages and clean internal interface;
  2399 
  2400 * prlim command for dealing with lots of subgoals (an easier way of
  2401 setting goals_limit);
  2402 
  2403 
  2404 *** Syntax ***
  2405 
  2406 * supports alternative (named) syntax tables (parser and pretty
  2407 printer); internal interface is provided by add_modesyntax(_i);
  2408 
  2409 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2410 be used in conjunction with the Isabelle symbol font; uses the
  2411 "symbols" syntax table;
  2412 
  2413 * added token_translation interface (may translate name tokens in
  2414 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2415 the current print_mode); IMPORTANT: user print translation functions
  2416 are responsible for marking newly introduced bounds
  2417 (Syntax.mark_boundT);
  2418 
  2419 * token translations for modes "xterm" and "xterm_color" that display
  2420 names in bold, underline etc. or colors (which requires a color
  2421 version of xterm);
  2422 
  2423 * infixes may now be declared with names independent of their syntax;
  2424 
  2425 * added typed_print_translation (like print_translation, but may
  2426 access type of constant);
  2427 
  2428 
  2429 *** Classical Reasoner ***
  2430 
  2431 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2432 some limitations.  Blast_tac...
  2433   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2434   + ignores elimination rules that don't have the correct format
  2435         (the conclusion MUST be a formula variable)
  2436   + ignores types, which can make HOL proofs fail
  2437   + rules must not require higher-order unification, e.g. apply_type in ZF
  2438     [message "Function Var's argument not a bound variable" relates to this]
  2439   + its proof strategy is more general but can actually be slower
  2440 
  2441 * substitution with equality assumptions no longer permutes other
  2442 assumptions;
  2443 
  2444 * minor changes in semantics of addafter (now called addaltern); renamed
  2445 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2446 (and access functions for it);
  2447 
  2448 * improved combination of classical reasoner and simplifier:
  2449   + functions for handling clasimpsets
  2450   + improvement of addss: now the simplifier is called _after_ the
  2451     safe steps.
  2452   + safe variant of addss called addSss: uses safe simplifications
  2453     _during_ the safe steps. It is more complete as it allows multiple
  2454     instantiations of unknowns (e.g. with slow_tac).
  2455 
  2456 *** Simplifier ***
  2457 
  2458 * added interface for simplification procedures (functions that
  2459 produce *proven* rewrite rules on the fly, depending on current
  2460 redex);
  2461 
  2462 * ordering on terms as parameter (used for ordered rewriting);
  2463 
  2464 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2465 
  2466 * the solver is now split into a safe and an unsafe part.
  2467 This should be invisible for the normal user, except that the
  2468 functions setsolver and addsolver have been renamed to setSolver and
  2469 addSolver; added safe_asm_full_simp_tac;
  2470 
  2471 
  2472 *** HOL ***
  2473 
  2474 * a generic induction tactic `induct_tac' which works for all datatypes and
  2475 also for type `nat';
  2476 
  2477 * a generic case distinction tactic `exhaust_tac' which works for all
  2478 datatypes and also for type `nat';
  2479 
  2480 * each datatype comes with a function `size';
  2481 
  2482 * patterns in case expressions allow tuple patterns as arguments to
  2483 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2484 
  2485 * primrec now also works with type nat;
  2486 
  2487 * recdef: a new declaration form, allows general recursive functions to be
  2488 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2489 
  2490 * the constant for negation has been renamed from "not" to "Not" to
  2491 harmonize with FOL, ZF, LK, etc.;
  2492 
  2493 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2494 infinite lists;
  2495 
  2496 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2497 
  2498 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2499 problems in commutative rings, using axiomatic type classes for + and *;
  2500 
  2501 * more examples in HOL/MiniML and HOL/Auth;
  2502 
  2503 * more default rewrite rules for quantifiers, union/intersection;
  2504 
  2505 * a new constant `arbitrary == @x.False';
  2506 
  2507 * HOLCF/IOA replaces old HOL/IOA;
  2508 
  2509 * HOLCF changes: derived all rules and arities
  2510   + axiomatic type classes instead of classes
  2511   + typedef instead of faking type definitions
  2512   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2513   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2514   + eliminated the types void, one, tr
  2515   + use unit lift and bool lift (with translations) instead of one and tr
  2516   + eliminated blift from Lift3.thy (use Def instead of blift)
  2517   all eliminated rules are derived as theorems --> no visible changes ;
  2518 
  2519 
  2520 *** ZF ***
  2521 
  2522 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2523 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2524 as ZF_cs addSIs [equalityI];
  2525 
  2526 
  2527 
  2528 New in Isabelle94-7 (November 96)
  2529 ---------------------------------
  2530 
  2531 * allowing negative levels (as offsets) in prlev and choplev;
  2532 
  2533 * super-linear speedup for large simplifications;
  2534 
  2535 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2536 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2537 FAIL); can suppress it using the command Delsimps (ex_simps @
  2538 all_simps); De Morgan laws are also now included, by default;
  2539 
  2540 * improved printing of ==>  :  ~:
  2541 
  2542 * new object-logic "Sequents" adds linear logic, while replacing LK
  2543 and Modal (thanks to Sara Kalvala);
  2544 
  2545 * HOL/Auth: correctness proofs for authentication protocols;
  2546 
  2547 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2548 examples on HOL/Auth);
  2549 
  2550 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2551 the rewriter and classical reasoner simultaneously;
  2552 
  2553 * function uresult no longer returns theorems in "standard" format;
  2554 regain previous version by: val uresult = standard o uresult;
  2555 
  2556 
  2557 
  2558 New in Isabelle94-6
  2559 -------------------
  2560 
  2561 * oracles -- these establish an interface between Isabelle and trusted
  2562 external reasoners, which may deliver results as theorems;
  2563 
  2564 * proof objects (in particular record all uses of oracles);
  2565 
  2566 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2567 
  2568 * "constdefs" section in theory files;
  2569 
  2570 * "primrec" section (HOL) no longer requires names;
  2571 
  2572 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2573 
  2574 
  2575 
  2576 New in Isabelle94-5
  2577 -------------------
  2578 
  2579 * reduced space requirements;
  2580 
  2581 * automatic HTML generation from theories;
  2582 
  2583 * theory files no longer require "..." (quotes) around most types;
  2584 
  2585 * new examples, including two proofs of the Church-Rosser theorem;
  2586 
  2587 * non-curried (1994) version of HOL is no longer distributed;
  2588 
  2589 
  2590 
  2591 New in Isabelle94-4
  2592 -------------------
  2593 
  2594 * greatly reduced space requirements;
  2595 
  2596 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2597 
  2598 * searchable theorem database (see the section "Retrieving theorems" on
  2599 page 8 of the Reference Manual);
  2600 
  2601 * new examples, including Grabczewski's monumental case study of the
  2602 Axiom of Choice;
  2603 
  2604 * The previous version of HOL renamed to Old_HOL;
  2605 
  2606 * The new version of HOL (previously called CHOL) uses a curried syntax
  2607 for functions.  Application looks like f a b instead of f(a,b);
  2608 
  2609 * Mutually recursive inductive definitions finally work in HOL;
  2610 
  2611 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2612 translates to the operator "split";
  2613 
  2614 
  2615 
  2616 New in Isabelle94-3
  2617 -------------------
  2618 
  2619 * new infix operator, addss, allowing the classical reasoner to
  2620 perform simplification at each step of its search.  Example:
  2621         fast_tac (cs addss ss)
  2622 
  2623 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2624 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2625 look like (a,b) instead of <a,b>;
  2626 
  2627 * PLEASE NOTE: CHOL will eventually replace HOL!
  2628 
  2629 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2630 It translates to the operator "split".  A new theory of integers is available;
  2631 
  2632 * In ZF, integer numerals now denote two's-complement binary integers.
  2633 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2634 
  2635 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2636 of the Axiom of Choice;
  2637 
  2638 
  2639 
  2640 New in Isabelle94-2
  2641 -------------------
  2642 
  2643 * Significantly faster resolution;
  2644 
  2645 * the different sections in a .thy file can now be mixed and repeated
  2646 freely;
  2647 
  2648 * Database of theorems for FOL, HOL and ZF.  New
  2649 commands including qed, qed_goal and bind_thm store theorems in the database.
  2650 
  2651 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2652 a given theory (thms_of), or find out what theory a theorem was proved in
  2653 (theory_of_thm);
  2654 
  2655 * Bugs fixed in the inductive definition and datatype packages;
  2656 
  2657 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2658 and HOL_dup_cs obsolete;
  2659 
  2660 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2661 have been removed;
  2662 
  2663 * Simpler definition of function space in ZF;
  2664 
  2665 * new results about cardinal and ordinal arithmetic in ZF;
  2666 
  2667 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2668 types;
  2669 
  2670 
  2671 $Id$