NEWS
author nipkow
Wed May 26 14:57:06 2004 +0200 (2004-05-26)
changeset 14804 8de39d3e8eb6
parent 14795 b702848de41f
child 14816 b77cebcd7e6e
permissions -rw-r--r--
Corrected printer bug for bounded quantifiers Q x<=y. P
     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
    15   an identifier.  If all fails, consider to fall back on 'consts' and
    16   'defs' separately.
    17 
    18 * Pure: improved indexed syntax and implicit structures.  First of
    19   all, indexed syntax provides a notational device for subscripted
    20   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    21   expressions.  Secondly, in a local context with structure
    22   declarations, number indexes \<^sub>n or the empty index (default
    23   number 1) refer to a certain fixed variable implicitly; option
    24   show_structs controls printing of implicit structures.  Typical
    25   applications of these concepts involve record types and locales.
    26 
    27 * Pure: syntax of terms, types etc. includes (*(*nested*) comments*).
    28 
    29 * Pure: 'advanced' translation functions (parse_translation etc.) may
    30   depend on the signature of the theory context being presently used
    31   for parsing/printing, see also isar-ref manual.
    32 
    33 * Pure: tuned internal renaming of symbolic identifiers -- attach
    34   primes instead of base 26 numbers.
    35 
    36 * Pure: clear separation of logical types and nonterminals, where the
    37   latter may only occur in 'syntax' specifications or type
    38   abbreviations.  Before that distinction was only partially
    39   implemented via type class "logic" vs. "{}".  Potential
    40   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    41   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    42   specifications requiring additional non-logical non-syntactic types
    43   (apart from 'prop' vs. 'logic') may need to be reformulated with
    44   duplicated 'consts'/'syntax' declarations (e.g. see Cube/Base.thy).
    45 
    46 
    47 *** HOL ***
    48 
    49 * HOL/record: reimplementation of records. Improved scalability for
    50   records with many fields, avoiding performance problems for type
    51   inference. Records are no longer composed of nested field types, but
    52   of nested extension types. Therefore the record type only grows
    53   linear in the number of extensions and not in the number of fields.
    54   The top-level (users) view on records is preserved.  Potential
    55   INCOMPATIBILITY only in strange cases, where the theory depends on
    56   the old record representation. The type generated for a record is
    57   called <record_name>_ext_type.
    58 
    59 * Simplifier: "record_upd_simproc" for simplification of multiple
    60   record updates enabled by default.  INCOMPATIBILITY: old proofs
    61   break occasionally, since simplification is more powerful by
    62   default.
    63 
    64 
    65 *** HOLCF ***
    66 
    67 * HOLCF: discontinued special version of 'constdefs' (which used to
    68   support continuous functions) in favor of the general Pure one with
    69   full type-inference.
    70 
    71 
    72 
    73 New in Isabelle2004 (April 2004)
    74 --------------------------------
    75 
    76 *** General ***
    77 
    78 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    79   Replaces linorder.ML.
    80 
    81 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
    82   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
    83   (\<a>...\<z>), are now considered normal letters, and can therefore
    84   be used anywhere where an ASCII letter (a...zA...Z) has until
    85   now. COMPATIBILITY: This obviously changes the parsing of some
    86   terms, especially where a symbol has been used as a binder, say
    87   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    88   as an identifier.  Fix it by inserting a space around former
    89   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    90   existing theory and ML files.
    91 
    92 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    93 
    94 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
    95   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
    96   a normal (but invisible) letter. For multiple letter subscripts repeat
    97   \<^isub> like this: x\<^isub>1\<^isub>2.
    98 
    99 * Pure: There are now sub-/superscripts that can span more than one
   100   character. Text between \<^bsub> and \<^esub> is set in subscript in
   101   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   102   superscript. The new control characters are not identifier parts.
   103 
   104 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   105   content of "..." to the latex file instead of \isacntrl... . The "..."
   106   may consist of any printable characters excluding the end bracket >.
   107 
   108 * Pure: Using new Isar command "finalconsts" (or the ML functions
   109   Theory.add_finals or Theory.add_finals_i) it is now possible to
   110   declare constants "final", which prevents their being given a definition
   111   later.  It is useful for constants whose behaviour is fixed axiomatically
   112   rather than definitionally, such as the meta-logic connectives.
   113 
   114 * Pure: 'instance' now handles general arities with general sorts
   115   (i.e. intersections of classes),
   116 
   117 * Presentation: generated HTML now uses a CSS style sheet to make layout
   118   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   119   It can be changed to alter the colors/layout of generated pages.
   120 
   121 
   122 *** Isar ***
   123 
   124 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   125   cut_tac, subgoal_tac and thin_tac:
   126   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   127     locales are no longer forced to write Isar proof scripts.
   128     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   129     emulations.
   130   - INCOMPATIBILITY: names of variables to be instantiated may no
   131     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   132     This is consistent with the instantiation attribute "where".
   133 
   134 * Attributes "where" and "of":
   135   - Now take type variables of instantiated theorem into account when reading
   136     the instantiation string.  This fixes a bug that caused instantiated
   137     theorems to have too special types in some circumstances.
   138   - "where" permits explicit instantiations of type variables.
   139 
   140 * Calculation commands "moreover" and "also" no longer interfere with
   141   current facts ("this"), admitting arbitrary combinations with "then"
   142   and derived forms.
   143 
   144 * Locales:
   145   - Goal statements involving the context element "includes" no longer
   146     generate theorems with internal delta predicates (those ending on
   147     "_axioms") in the premise.
   148     Resolve particular premise with <locale>.intro to obtain old form.
   149   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   150     specification and "includes" elements in goal statement.
   151   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   152     [intro?] and [elim?] (respectively) by default.
   153   - Experimental command for instantiation of locales in proof contexts:
   154         instantiate <label>[<attrs>]: <loc>
   155     Instantiates locale <loc> and adds all its theorems to the current context
   156     taking into account their attributes.  Label and attrs are optional
   157     modifiers, like in theorem declarations.  If present, names of
   158     instantiated theorems are qualified with <label>, and the attributes
   159     <attrs> are applied after any attributes these theorems might have already.
   160       If the locale has assumptions, a chained fact of the form
   161     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   162     are derived.  The command does not support old-style locales declared
   163     with "locale (open)".
   164       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   165 
   166 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   167   (Isar) contexts.
   168 
   169 
   170 *** HOL ***
   171 
   172 * Proof import: new image HOL4 contains the imported library from
   173   the HOL4 system with about 2500 theorems. It is imported by
   174   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   175   can be used like any other Isabelle image.  See
   176   HOL/Import/HOL/README for more information.
   177 
   178 * Simplifier:
   179   - Much improved handling of linear and partial orders.
   180     Reasoners for linear and partial orders are set up for type classes
   181     "linorder" and "order" respectively, and are added to the default simpset
   182     as solvers.  This means that the simplifier can build transitivity chains
   183     to solve goals from the assumptions.
   184   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   185     of blast or auto after simplification become unnecessary because the goal
   186     is solved by simplification already.
   187 
   188 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   189     all proved in axiomatic type classes for semirings, rings and fields.
   190 
   191 * Numerics:
   192   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   193     now formalized using the Ring_and_Field theory mentioned above.
   194   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   195     than before, because now they are set up once in a generic manner.
   196   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   197     Look for the general versions in Ring_and_Field (and Power if they concern
   198     exponentiation).
   199 
   200 * Type "rat" of the rational numbers is now available in HOL-Complex.
   201 
   202 * Records:
   203   - Record types are now by default printed with their type abbreviation
   204     instead of the list of all field types. This can be configured via
   205     the reference "print_record_type_abbr".
   206   - Simproc "record_upd_simproc" for simplification of multiple updates added
   207     (not enabled by default).
   208   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   209     EX x. x = sel r to True (not enabled by default).
   210   - Tactic "record_split_simp_tac" to split and simplify records added.
   211 
   212 * 'specification' command added, allowing for definition by
   213   specification.  There is also an 'ax_specification' command that
   214   introduces the new constants axiomatically.
   215 
   216 * arith(_tac) is now able to generate counterexamples for reals as well.
   217 
   218 * HOL-Algebra: new locale "ring" for non-commutative rings.
   219 
   220 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   221   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   222 
   223 * HOL-Matrix: a first theory for matrices in HOL with an application of
   224   matrix theory to linear programming.
   225 
   226 * Unions and Intersections:
   227   The x-symbol output syntax of UN and INT has been changed
   228   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   229   i.e. the index formulae has become a subscript, like in normal math.
   230   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   231   The subscript version is also accepted as input syntax.
   232 
   233 * Unions and Intersections over Intervals:
   234   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   235   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   236   like in normal math, and corresponding versions for < and for intersection.
   237 
   238 * ML: the legacy theory structures Int and List have been removed. They had
   239   conflicted with ML Basis Library structures having the same names.
   240 
   241 * 'refute' command added to search for (finite) countermodels.  Only works
   242   for a fragment of HOL.  The installation of an external SAT solver is
   243   highly recommended.  See "HOL/Refute.thy" for details.
   244 
   245 * 'quickcheck' command: Allows to find counterexamples by evaluating
   246   formulae under an assignment of free variables to random values.
   247   In contrast to 'refute', it can deal with inductive datatypes,
   248   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   249   for examples.
   250 
   251 
   252 *** HOLCF ***
   253 
   254 * Streams now come with concatenation and are part of the HOLCF image
   255 
   256 
   257 
   258 New in Isabelle2003 (May 2003)
   259 ------------------------------
   260 
   261 *** General ***
   262 
   263 * Provers/simplifier:
   264 
   265   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   266     Assumptions are now subject to complete mutual simplification,
   267     not just from left to right. The simplifier now preserves
   268     the order of assumptions.
   269 
   270     Potential INCOMPATIBILITY:
   271 
   272     -- simp sometimes diverges where the old version did
   273        not, e.g. invoking simp on the goal
   274 
   275         [| P (f x); y = x; f x = f y |] ==> Q
   276 
   277        now gives rise to the infinite reduction sequence
   278 
   279         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   280 
   281        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   282        kind of problem.
   283 
   284     -- Tactics combining classical reasoner and simplification (such as auto)
   285        are also affected by this change, because many of them rely on
   286        simp. They may sometimes diverge as well or yield a different numbers
   287        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   288        in case of problems. Sometimes subsequent calls to the classical
   289        reasoner will fail because a preceeding call to the simplifier too
   290        eagerly simplified the goal, e.g. deleted redundant premises.
   291 
   292   - The simplifier trace now shows the names of the applied rewrite rules
   293 
   294   - You can limit the number of recursive invocations of the simplifier
   295     during conditional rewriting (where the simplifie tries to solve the
   296     conditions before applying the rewrite rule):
   297     ML "simp_depth_limit := n"
   298     where n is an integer. Thus you can force termination where previously
   299     the simplifier would diverge.
   300 
   301   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   302 
   303   - No longer aborts on failed congruence proof.  Instead, the
   304     congruence is ignored.
   305 
   306 * Pure: New generic framework for extracting programs from constructive
   307   proofs. See HOL/Extraction.thy for an example instantiation, as well
   308   as HOL/Extraction for some case studies.
   309 
   310 * Pure: The main goal of the proof state is no longer shown by default, only
   311 the subgoals. This behaviour is controlled by a new flag.
   312    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   313 (ML: Proof.show_main_goal).
   314 
   315 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   316 rules whose conclusion matches subgoal 1:
   317       PG menu: Isabelle/Isar -> Show me -> matching rules
   318 The rules are ordered by how closely they match the subgoal.
   319 In particular, rules that solve a subgoal outright are displayed first
   320 (or rather last, the way they are printed).
   321 (ML: ProofGeneral.print_intros())
   322 
   323 * Pure: New flag trace_unify_fail causes unification to print
   324 diagnostic information (PG: in trace buffer) when it fails. This is
   325 useful for figuring out why single step proofs like rule, erule or
   326 assumption failed.
   327 
   328 * Pure: Locale specifications now produce predicate definitions
   329 according to the body of text (covering assumptions modulo local
   330 definitions); predicate "loc_axioms" covers newly introduced text,
   331 while "loc" is cumulative wrt. all included locale expressions; the
   332 latter view is presented only on export into the global theory
   333 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   334 on the old view without predicates;
   335 
   336 * Pure: predefined locales "var" and "struct" are useful for sharing
   337 parameters (as in CASL, for example); just specify something like
   338 ``var x + var y + struct M'' as import;
   339 
   340 * Pure: improved thms_containing: proper indexing of facts instead of
   341 raw theorems; check validity of results wrt. current name space;
   342 include local facts of proof configuration (also covers active
   343 locales), cover fixed variables in index; may use "_" in term
   344 specification; an optional limit for the number of printed facts may
   345 be given (the default is 40);
   346 
   347 * Pure: disallow duplicate fact bindings within new-style theory files
   348 (batch-mode only);
   349 
   350 * Provers: improved induct method: assumptions introduced by case
   351 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   352 the goal statement); "foo" still refers to all facts collectively;
   353 
   354 * Provers: the function blast.overloaded has been removed: all constants
   355 are regarded as potentially overloaded, which improves robustness in exchange
   356 for slight decrease in efficiency;
   357 
   358 * Provers/linorder: New generic prover for transitivity reasoning over
   359 linear orders.  Note: this prover is not efficient!
   360 
   361 * Isar: preview of problems to finish 'show' now produce an error
   362 rather than just a warning (in interactive mode);
   363 
   364 
   365 *** HOL ***
   366 
   367 * arith(_tac)
   368 
   369  - Produces a counter example if it cannot prove a goal.
   370    Note that the counter example may be spurious if the goal is not a formula
   371    of quantifier-free linear arithmetic.
   372    In ProofGeneral the counter example appears in the trace buffer.
   373 
   374  - Knows about div k and mod k where k is a numeral of type nat or int.
   375 
   376  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   377    linear arithmetic fails. This takes account of quantifiers and divisibility.
   378    Presburger arithmetic can also be called explicitly via presburger(_tac).
   379 
   380 * simp's arithmetic capabilities have been enhanced a bit: it now
   381 takes ~= in premises into account (by performing a case split);
   382 
   383 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   384 are distributed over a sum of terms;
   385 
   386 * New tactic "trans_tac" and method "trans" instantiate
   387 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   388 "<=", "<" and "=").
   389 
   390 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   391 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   392 
   393 * 'typedef' command has new option "open" to suppress the set
   394 definition;
   395 
   396 * functions Min and Max on finite sets have been introduced (theory
   397 Finite_Set);
   398 
   399 * attribute [symmetric] now works for relations as well; it turns
   400 (x,y) : R^-1 into (y,x) : R, and vice versa;
   401 
   402 * induct over a !!-quantified statement (say !!x1..xn):
   403   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   404 
   405 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   406 %x. None. Warning: empty_def now refers to the previously hidden definition
   407 of the empty set.
   408 
   409 * Algebra: formalization of classical algebra.  Intended as base for
   410 any algebraic development in Isabelle.  Currently covers group theory
   411 (up to Sylow's theorem) and ring theory (Universal Property of
   412 Univariate Polynomials).  Contributions welcome;
   413 
   414 * GroupTheory: deleted, since its material has been moved to Algebra;
   415 
   416 * Complex: new directory of the complex numbers with numeric constants,
   417 nonstandard complex numbers, and some complex analysis, standard and
   418 nonstandard (Jacques Fleuriot);
   419 
   420 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   421 
   422 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   423 Fleuriot);
   424 
   425 * Real/HahnBanach: updated and adapted to locales;
   426 
   427 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   428 Gray and Kramer);
   429 
   430 * UNITY: added the Meier-Sanders theory of progress sets;
   431 
   432 * MicroJava: bytecode verifier and lightweight bytecode verifier
   433 as abstract algorithms, instantiated to the JVM;
   434 
   435 * Bali: Java source language formalization. Type system, operational
   436 semantics, axiomatic semantics. Supported language features:
   437 classes, interfaces, objects,virtual methods, static methods,
   438 static/instance fields, arrays, access modifiers, definite
   439 assignment, exceptions.
   440 
   441 
   442 *** ZF ***
   443 
   444 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   445 universe, etc.);
   446 
   447 * Main ZF: virtually all theories converted to new-style format;
   448 
   449 
   450 *** ML ***
   451 
   452 * Pure: Tactic.prove provides sane interface for internal proofs;
   453 omits the infamous "standard" operation, so this is more appropriate
   454 than prove_goalw_cterm in many situations (e.g. in simprocs);
   455 
   456 * Pure: improved error reporting of simprocs;
   457 
   458 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   459 up simprocs;
   460 
   461 
   462 *** Document preparation ***
   463 
   464 * uses \par instead of \\ for line breaks in theory text. This may
   465 shift some page breaks in large documents. To get the old behaviour
   466 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   467 
   468 * minimized dependencies of isabelle.sty and isabellesym.sty on
   469 other packages
   470 
   471 * \<euro> now needs package babel/greek instead of marvosym (which
   472 broke \Rightarrow)
   473 
   474 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   475 textcomp package)
   476 
   477 
   478 
   479 New in Isabelle2002 (March 2002)
   480 --------------------------------
   481 
   482 *** Document preparation ***
   483 
   484 * greatly simplified document preparation setup, including more
   485 graceful interpretation of isatool usedir -i/-d/-D options, and more
   486 instructive isatool mkdir; users should basically be able to get
   487 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   488 users may run a separate document processing stage manually like this:
   489 "isatool usedir -D output HOL Test && isatool document Test/output";
   490 
   491 * theory dependency graph may now be incorporated into documents;
   492 isatool usedir -g true will produce session_graph.eps/.pdf for use
   493 with \includegraphics of LaTeX;
   494 
   495 * proper spacing of consecutive markup elements, especially text
   496 blocks after section headings;
   497 
   498 * support bold style (for single symbols only), input syntax is like
   499 this: "\<^bold>\<alpha>" or "\<^bold>A";
   500 
   501 * \<bullet> is now output as bold \cdot by default, which looks much
   502 better in printed text;
   503 
   504 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   505 note that these symbols are currently unavailable in Proof General /
   506 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   507 
   508 * isatool latex no longer depends on changed TEXINPUTS, instead
   509 isatool document copies the Isabelle style files to the target
   510 location;
   511 
   512 
   513 *** Isar ***
   514 
   515 * Pure/Provers: improved proof by cases and induction;
   516   - 'case' command admits impromptu naming of parameters (such as
   517     "case (Suc n)");
   518   - 'induct' method divinates rule instantiation from the inductive
   519     claim; no longer requires excessive ?P bindings for proper
   520     instantiation of cases;
   521   - 'induct' method properly enumerates all possibilities of set/type
   522     rules; as a consequence facts may be also passed through *type*
   523     rules without further ado;
   524   - 'induct' method now derives symbolic cases from the *rulified*
   525     rule (before it used to rulify cases stemming from the internal
   526     atomized version); this means that the context of a non-atomic
   527     statement becomes is included in the hypothesis, avoiding the
   528     slightly cumbersome show "PROP ?case" form;
   529   - 'induct' may now use elim-style induction rules without chaining
   530     facts, using ``missing'' premises from the goal state; this allows
   531     rules stemming from inductive sets to be applied in unstructured
   532     scripts, while still benefitting from proper handling of non-atomic
   533     statements; NB: major inductive premises need to be put first, all
   534     the rest of the goal is passed through the induction;
   535   - 'induct' proper support for mutual induction involving non-atomic
   536     rule statements (uses the new concept of simultaneous goals, see
   537     below);
   538   - append all possible rule selections, but only use the first
   539     success (no backtracking);
   540   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   541   - undeclared rule case names default to numbers 1, 2, 3, ...;
   542   - added 'print_induct_rules' (covered by help item in recent Proof
   543     General versions);
   544   - moved induct/cases attributes to Pure, methods to Provers;
   545   - generic method setup instantiated for FOL and HOL;
   546 
   547 * Pure: support multiple simultaneous goal statements, for example
   548 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   549 meta-level mechanism, this acts as if several individual goals had
   550 been stated separately; in particular common proof methods need to be
   551 repeated in order to cover all claims; note that a single elimination
   552 step is *not* sufficient to establish the two conjunctions, so this
   553 fails:
   554 
   555   assume "A & B" then have A and B ..   (*".." fails*)
   556 
   557 better use "obtain" in situations as above; alternative refer to
   558 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   559 
   560 * Pure: proper integration with ``locales''; unlike the original
   561 version by Florian Kammüller, Isar locales package high-level proof
   562 contexts rather than raw logical ones (e.g. we admit to include
   563 attributes everywhere); operations on locales include merge and
   564 rename; support for implicit arguments (``structures''); simultaneous
   565 type-inference over imports and text; see also HOL/ex/Locales.thy for
   566 some examples;
   567 
   568 * Pure: the following commands have been ``localized'', supporting a
   569 target locale specification "(in name)": 'lemma', 'theorem',
   570 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   571 stored both within the locale and at the theory level (exported and
   572 qualified by the locale name);
   573 
   574 * Pure: theory goals may now be specified in ``long'' form, with
   575 ad-hoc contexts consisting of arbitrary locale elements. for example
   576 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   577 definitions may be given, too); the result is a meta-level rule with
   578 the context elements being discharged in the obvious way;
   579 
   580 * Pure: new proof command 'using' allows to augment currently used
   581 facts after a goal statement ('using' is syntactically analogous to
   582 'apply', but acts on the goal's facts only); this allows chained facts
   583 to be separated into parts given before and after a claim, as in
   584 ``from a and b have C using d and e <proof>'';
   585 
   586 * Pure: renamed "antecedent" case to "rule_context";
   587 
   588 * Pure: new 'judgment' command records explicit information about the
   589 object-logic embedding (used by several tools internally); no longer
   590 use hard-wired "Trueprop";
   591 
   592 * Pure: added 'corollary' command;
   593 
   594 * Pure: fixed 'token_translation' command;
   595 
   596 * Pure: removed obsolete 'exported' attribute;
   597 
   598 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   599 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   600 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   601 
   602 * Pure: method 'atomize' presents local goal premises as object-level
   603 statements (atomic meta-level propositions); setup controlled via
   604 rewrite rules declarations of 'atomize' attribute; example
   605 application: 'induct' method with proper rule statements in improper
   606 proof *scripts*;
   607 
   608 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   609 now consider the syntactic context of assumptions, giving a better
   610 chance to get type-inference of the arguments right (this is
   611 especially important for locales);
   612 
   613 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   614 mode;
   615 
   616 * Pure/obtain: the formal conclusion "thesis", being marked as
   617 ``internal'', may no longer be reference directly in the text;
   618 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   619 situations;
   620 
   621 * Pure: generic 'sym' attribute which declares a rule both as pure
   622 'elim?' and for the 'symmetric' operation;
   623 
   624 * Pure: marginal comments ``--'' may now occur just anywhere in the
   625 text; the fixed correlation with particular command syntax has been
   626 discontinued;
   627 
   628 * Pure: new method 'rules' is particularly well-suited for proof
   629 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   630 but often produces more compact proof terms with less detours;
   631 
   632 * Pure/Provers/classical: simplified integration with pure rule
   633 attributes and methods; the classical "intro?/elim?/dest?"
   634 declarations coincide with the pure ones; the "rule" method no longer
   635 includes classically swapped intros; "intro" and "elim" methods no
   636 longer pick rules from the context; also got rid of ML declarations
   637 AddXIs/AddXEs/AddXDs; all of this has some potential for
   638 INCOMPATIBILITY;
   639 
   640 * Provers/classical: attribute 'swapped' produces classical inversions
   641 of introduction rules;
   642 
   643 * Provers/simplifier: 'simplified' attribute may refer to explicit
   644 rules instead of full simplifier context; 'iff' attribute handles
   645 conditional rules;
   646 
   647 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   648 
   649 * HOL: 'recdef' now fails on unfinished automated proofs, use
   650 "(permissive)" option to recover old behavior;
   651 
   652 * HOL: 'inductive' no longer features separate (collective) attributes
   653 for 'intros' (was found too confusing);
   654 
   655 * HOL: properly declared induction rules less_induct and
   656 wf_induct_rule;
   657 
   658 
   659 *** HOL ***
   660 
   661 * HOL: moved over to sane numeral syntax; the new policy is as
   662 follows:
   663 
   664   - 0 and 1 are polymorphic constants, which are defined on any
   665   numeric type (nat, int, real etc.);
   666 
   667   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   668   binary representation internally;
   669 
   670   - type nat has special constructor Suc, and generally prefers Suc 0
   671   over 1::nat and Suc (Suc 0) over 2::nat;
   672 
   673 This change may cause significant problems of INCOMPATIBILITY; here
   674 are some hints on converting existing sources:
   675 
   676   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   677   entities, so expressions involving "-" (unary or binary minus) need
   678   to be spaced properly;
   679 
   680   - existing occurrences of "1" may need to be constraint "1::nat" or
   681   even replaced by Suc 0; similar for old "2";
   682 
   683   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   684 
   685   - remove all special provisions on numerals in proofs;
   686 
   687 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   688 representation (depends on bin_arith_simps in the default context);
   689 
   690 * HOL: symbolic syntax for x^2 (numeral 2);
   691 
   692 * HOL: the class of all HOL types is now called "type" rather than
   693 "term"; INCOMPATIBILITY, need to adapt references to this type class
   694 in axclass/classes, instance/arities, and (usually rare) occurrences
   695 in typings (of consts etc.); internally the class is called
   696 "HOL.type", ML programs should refer to HOLogic.typeS;
   697 
   698 * HOL/record package improvements:
   699   - new derived operations "fields" to build a partial record section,
   700     "extend" to promote a fixed record to a record scheme, and
   701     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   702     declared as simp by default;
   703   - shared operations ("more", "fields", etc.) now need to be always
   704     qualified) --- potential INCOMPATIBILITY;
   705   - removed "make_scheme" operations (use "make" with "extend") --
   706     INCOMPATIBILITY;
   707   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   708   - provides cases/induct rules for use with corresponding Isar
   709     methods (for concrete records, record schemes, concrete more
   710     parts, and schematic more parts -- in that order);
   711   - internal definitions directly based on a light-weight abstract
   712     theory of product types over typedef rather than datatype;
   713 
   714 * HOL: generic code generator for generating executable ML code from
   715 specifications; specific support for HOL constructs such as inductive
   716 datatypes and sets, as well as recursive functions; can be invoked
   717 via 'generate_code' theory section;
   718 
   719 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   720 
   721 * HOL: consolidated and renamed several theories.  In particular:
   722         Ord.thy has been absorbed into HOL.thy
   723         String.thy has been absorbed into List.thy
   724 
   725 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   726 (beware of argument permutation!);
   727 
   728 * HOL: linorder_less_split superseded by linorder_cases;
   729 
   730 * HOL/List: "nodups" renamed to "distinct";
   731 
   732 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   733 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   734   - Ex_def has changed, now need to use some_eq_ex
   735 
   736 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   737 in this (rare) case use:
   738 
   739   delSWrapper "split_all_tac"
   740   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   741 
   742 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   743 MAY FAIL;
   744 
   745 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   746 Isabelle's type classes, ^ on functions and relations has too general
   747 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   748 necessary to attach explicit type constraints;
   749 
   750 * HOL/Relation: the prefix name of the infix "O" has been changed from
   751 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   752 renamed accordingly (eg "compI" -> "rel_compI").
   753 
   754 * HOL: syntax translations now work properly with numerals and records
   755 expressions;
   756 
   757 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   758 of "lam" -- INCOMPATIBILITY;
   759 
   760 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   761 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   762 renamed "Product_Type.unit";
   763 
   764 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   765 
   766 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   767 the "cases" method);
   768 
   769 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   770 Florian Kammüller);
   771 
   772 * HOL/IMP: updated and converted to new-style theory format; several
   773 parts turned into readable document, with proper Isar proof texts and
   774 some explanations (by Gerwin Klein);
   775 
   776 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   777 
   778 * HOL-Hyperreal is now a logic image;
   779 
   780 
   781 *** HOLCF ***
   782 
   783 * Isar: consts/constdefs supports mixfix syntax for continuous
   784 operations;
   785 
   786 * Isar: domain package adapted to new-style theory format, e.g. see
   787 HOLCF/ex/Dnat.thy;
   788 
   789 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   790 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   791 lift.induct_tac, always use UU instead of Undef;
   792 
   793 * HOLCF/IMP: updated and converted to new-style theory;
   794 
   795 
   796 *** ZF ***
   797 
   798 * Isar: proper integration of logic-specific tools and packages,
   799 including theory commands '(co)inductive', '(co)datatype',
   800 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   801 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   802 
   803 * theory Main no longer includes AC; for the Axiom of Choice, base
   804 your theory on Main_ZFC;
   805 
   806 * the integer library now covers quotients and remainders, with many
   807 laws relating division to addition, multiplication, etc.;
   808 
   809 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   810 typeless version of the formalism;
   811 
   812 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   813 format;
   814 
   815 * ZF/Induct: new directory for examples of inductive definitions,
   816 including theory Multiset for multiset orderings; converted to
   817 new-style theory format;
   818 
   819 * ZF: many new theorems about lists, ordinals, etc.;
   820 
   821 
   822 *** General ***
   823 
   824 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   825 variable proof controls level of detail: 0 = no proofs (only oracle
   826 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   827 also ref manual for further ML interfaces;
   828 
   829 * Pure/axclass: removed obsolete ML interface
   830 goal_subclass/goal_arity;
   831 
   832 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   833 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   834 separate tokens, so expressions involving minus need to be spaced
   835 properly;
   836 
   837 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   838 rather than "infixl" or "infixr";
   839 
   840 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   841 sort constraint specifications in type inference; e.g. "x::_::foo"
   842 ensures that the type of "x" is of sort "foo" (but not necessarily a
   843 type variable);
   844 
   845 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   846 control output of nested => (types); the default behavior is
   847 "type_brackets";
   848 
   849 * Pure/syntax: builtin parse translation for "_constify" turns valued
   850 tokens into AST constants;
   851 
   852 * Pure/syntax: prefer later declarations of translations and print
   853 translation functions; potential INCOMPATIBILITY: need to reverse
   854 multiple declarations for same syntax element constant;
   855 
   856 * Pure/show_hyps reset by default (in accordance to existing Isar
   857 practice);
   858 
   859 * Provers/classical: renamed addaltern to addafter, addSaltern to
   860 addSafter;
   861 
   862 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   863 as well;
   864 
   865 * system: tested support for MacOS X; should be able to get Isabelle +
   866 Proof General to work in a plain Terminal after installing Poly/ML
   867 (e.g. from the Isabelle distribution area) and GNU bash alone
   868 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   869 support requires further installations, e.g. from
   870 http://fink.sourceforge.net/);
   871 
   872 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   873 
   874 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   875 of 40 MB), cf. ML_OPTIONS;
   876 
   877 * system: Proof General keywords specification is now part of the
   878 Isabelle distribution (see etc/isar-keywords.el);
   879 
   880 * system: support for persistent Proof General sessions (refrain from
   881 outdating all loaded theories on startup); user may create writable
   882 logic images like this: ``isabelle -q HOL Test'';
   883 
   884 * system: smart selection of Isabelle process versus Isabelle
   885 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   886 run both "isabelle" and "Isabelle" even if file names are badly
   887 damaged (executable inspects the case of the first letter of its own
   888 name); added separate "isabelle-process" and "isabelle-interface";
   889 
   890 * system: refrain from any attempt at filtering input streams; no
   891 longer support ``8bit'' encoding of old isabelle font, instead proper
   892 iso-latin characters may now be used; the related isatools
   893 "symbolinput" and "nonascii" have disappeared as well;
   894 
   895 * system: removed old "xterm" interface (the print modes "xterm" and
   896 "xterm_color" are still available for direct use in a suitable
   897 terminal);
   898 
   899 
   900 
   901 New in Isabelle99-2 (February 2001)
   902 -----------------------------------
   903 
   904 *** Overview of INCOMPATIBILITIES ***
   905 
   906 * HOL: please note that theories in the Library and elsewhere often use the
   907 new-style (Isar) format; to refer to their theorems in an ML script you must
   908 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   909 
   910 * HOL: inductive package no longer splits induction rule aggressively,
   911 but only as far as specified by the introductions given; the old
   912 format may be recovered via ML function complete_split_rule or attribute
   913 'split_rule (complete)';
   914 
   915 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   916 gfp_Tarski to gfp_unfold;
   917 
   918 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   919 
   920 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   921 relation); infix "^^" has been renamed "``"; infix "``" has been
   922 renamed "`"; "univalent" has been renamed "single_valued";
   923 
   924 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   925 operation;
   926 
   927 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   928 
   929 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   930 
   931 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   932 consequence, it is no longer monotonic wrt. the local goal context
   933 (which is now passed through the inductive cases);
   934 
   935 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   936 \<gg> to \<ggreater>;
   937 
   938 
   939 *** Document preparation ***
   940 
   941 * \isabellestyle{NAME} selects version of Isabelle output (currently
   942 available: are "it" for near math-mode best-style output, "sl" for
   943 slanted text style, and "tt" for plain type-writer; if no
   944 \isabellestyle command is given, output is according to slanted
   945 type-writer);
   946 
   947 * support sub/super scripts (for single symbols only), input syntax is
   948 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   949 
   950 * some more standard symbols; see Appendix A of the system manual for
   951 the complete list of symbols defined in isabellesym.sty;
   952 
   953 * improved isabelle style files; more abstract symbol implementation
   954 (should now use \isamath{...} and \isatext{...} in custom symbol
   955 definitions);
   956 
   957 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   958 state; Note that presentation of goal states does not conform to
   959 actual human-readable proof documents.  Please do not include goal
   960 states into document output unless you really know what you are doing!
   961 
   962 * proper indentation of antiquoted output with proportional LaTeX
   963 fonts;
   964 
   965 * no_document ML operator temporarily disables LaTeX document
   966 generation;
   967 
   968 * isatool unsymbolize tunes sources for plain ASCII communication;
   969 
   970 
   971 *** Isar ***
   972 
   973 * Pure: Isar now suffers initial goal statements to contain unbound
   974 schematic variables (this does not conform to actual readable proof
   975 documents, due to unpredictable outcome and non-compositional proof
   976 checking); users who know what they are doing may use schematic goals
   977 for Prolog-style synthesis of proven results;
   978 
   979 * Pure: assumption method (an implicit finishing) now handles actual
   980 rules as well;
   981 
   982 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   983 initial goal, declare "that" only as Pure intro (only for single
   984 steps); the "that" rule assumption may now be involved in implicit
   985 finishing, thus ".." becomes a feasible for trivial obtains;
   986 
   987 * Pure: default proof step now includes 'intro_classes'; thus trivial
   988 instance proofs may be performed by "..";
   989 
   990 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   991 statements as well;
   992 
   993 * Pure: more robust selection of calculational rules;
   994 
   995 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   996 rule (as well as the assumption rule);
   997 
   998 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   999 lemmas, using the graph browser tool;
  1000 
  1001 * Pure: predict failure of "show" in interactive mode;
  1002 
  1003 * Pure: 'thms_containing' now takes actual terms as arguments;
  1004 
  1005 * HOL: improved method 'induct' --- now handles non-atomic goals
  1006 (potential INCOMPATIBILITY); tuned error handling;
  1007 
  1008 * HOL: cases and induct rules now provide explicit hints about the
  1009 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1010 any remaining facts are inserted into the goal verbatim;
  1011 
  1012 * HOL: local contexts (aka cases) may now contain term bindings as
  1013 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1014 the result to be shown in each case;
  1015 
  1016 * HOL: added 'recdef_tc' command;
  1017 
  1018 * isatool convert assists in eliminating legacy ML scripts;
  1019 
  1020 
  1021 *** HOL ***
  1022 
  1023 * HOL/Library: a collection of generic theories to be used together
  1024 with main HOL; the theory loader path already includes this directory
  1025 by default; the following existing theories have been moved here:
  1026 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1027 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1028 
  1029 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1030 modelling and verification task performed in Isabelle/HOL +
  1031 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1032 
  1033 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1034 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1035 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1036 'domain', this makes the theory consistent with mathematical
  1037 literature;
  1038 
  1039 * HOL basics: added overloaded operations "inverse" and "divide"
  1040 (infix "/"), syntax for generic "abs" operation, generic summation
  1041 operator \<Sum>;
  1042 
  1043 * HOL/typedef: simplified package, provide more useful rules (see also
  1044 HOL/subset.thy);
  1045 
  1046 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1047 now expressed as a proper nested rule (old-style tactic scripts may
  1048 require atomize_strip_tac to cope with non-atomic premises);
  1049 
  1050 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1051 to "split_conv" (old name still available for compatibility);
  1052 
  1053 * HOL: improved concrete syntax for strings (e.g. allows translation
  1054 rules with string literals);
  1055 
  1056 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1057  and Fleuriot's mechanization of analysis, including the transcendental
  1058  functions for the reals;
  1059 
  1060 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1061 
  1062 
  1063 *** CTT ***
  1064 
  1065 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1066 "lam" is displayed as TWO lambda-symbols
  1067 
  1068 * CTT: theory Main now available, containing everything (that is, Bool
  1069 and Arith);
  1070 
  1071 
  1072 *** General ***
  1073 
  1074 * Pure: the Simplifier has been implemented properly as a derived rule
  1075 outside of the actual kernel (at last!); the overall performance
  1076 penalty in practical applications is about 50%, while reliability of
  1077 the Isabelle inference kernel has been greatly improved;
  1078 
  1079 * print modes "brackets" and "no_brackets" control output of nested =>
  1080 (types) and ==> (props); the default behaviour is "brackets";
  1081 
  1082 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1083 as assumptions as well;
  1084 
  1085 * system: support Poly/ML 4.0;
  1086 
  1087 * system: isatool install handles KDE version 1 or 2;
  1088 
  1089 
  1090 
  1091 New in Isabelle99-1 (October 2000)
  1092 ----------------------------------
  1093 
  1094 *** Overview of INCOMPATIBILITIES ***
  1095 
  1096 * HOL: simplification of natural numbers is much changed; to partly
  1097 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1098 issue the following ML commands:
  1099 
  1100   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1101   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1102 
  1103 * HOL: simplification no longer dives into case-expressions; this is
  1104 controlled by "t.weak_case_cong" for each datatype t;
  1105 
  1106 * HOL: nat_less_induct renamed to less_induct;
  1107 
  1108 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1109 fixsome to patch .thy and .ML sources automatically;
  1110 
  1111   select_equality  -> some_equality
  1112   select_eq_Ex     -> some_eq_ex
  1113   selectI2EX       -> someI2_ex
  1114   selectI2         -> someI2
  1115   selectI          -> someI
  1116   select1_equality -> some1_equality
  1117   Eps_sym_eq       -> some_sym_eq_trivial
  1118   Eps_eq           -> some_eq_trivial
  1119 
  1120 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1121 
  1122 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1123 instead);
  1124 
  1125 * HOL: the recursion equations generated by 'recdef' are now called
  1126 f.simps instead of f.rules;
  1127 
  1128 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1129 
  1130 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1131 sometimes be needed;
  1132 
  1133 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1134 
  1135 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1136 
  1137 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1138 product is now "<*>" instead of "Times"; the lexicographic product is
  1139 now "<*lex*>" instead of "**";
  1140 
  1141 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1142 of main HOL, but was unused); better use HOL's datatype package;
  1143 
  1144 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1145 the old syntax may be recovered as follows:
  1146 
  1147   syntax (symbols)
  1148     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1149       (infixl "\\<oplus>" 100)
  1150 
  1151 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1152 
  1153 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1154 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1155 internally;
  1156 
  1157 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1158 changed from A/r to A//r;
  1159 
  1160 * ZF: new treatment of arithmetic (nat & int) may break some old
  1161 proofs;
  1162 
  1163 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1164 rulify -> rule_format, elimify -> elim_format, ...);
  1165 
  1166 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1167 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1168 should have to change intro!! to intro? only); replaced "delrule" by
  1169 "rule del";
  1170 
  1171 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1172 
  1173 * Provers: strengthened force_tac by using new first_best_tac;
  1174 
  1175 * LaTeX document preparation: several changes of isabelle.sty (see
  1176 lib/texinputs);
  1177 
  1178 
  1179 *** Document preparation ***
  1180 
  1181 * formal comments (text blocks etc.) in new-style theories may now
  1182 contain antiquotations of thm/prop/term/typ/text to be presented
  1183 according to latex print mode; concrete syntax is like this:
  1184 @{term[show_types] "f(x) = a + x"};
  1185 
  1186 * isatool mkdir provides easy setup of Isabelle session directories,
  1187 including proper document sources;
  1188 
  1189 * generated LaTeX sources are now deleted after successful run
  1190 (isatool document -c); may retain a copy somewhere else via -D option
  1191 of isatool usedir;
  1192 
  1193 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1194 style files, achieving self-contained LaTeX sources and simplifying
  1195 LaTeX debugging;
  1196 
  1197 * old-style theories now produce (crude) LaTeX output as well;
  1198 
  1199 * browser info session directories are now self-contained (may be put
  1200 on WWW server seperately); improved graphs of nested sessions; removed
  1201 graph for 'all sessions';
  1202 
  1203 * several improvements in isabelle style files; \isabellestyle{it}
  1204 produces fake math mode output; \isamarkupheader is now \section by
  1205 default; see lib/texinputs/isabelle.sty etc.;
  1206 
  1207 
  1208 *** Isar ***
  1209 
  1210 * Isar/Pure: local results and corresponding term bindings are now
  1211 subject to Hindley-Milner polymorphism (similar to ML); this
  1212 accommodates incremental type-inference very nicely;
  1213 
  1214 * Isar/Pure: new derived language element 'obtain' supports
  1215 generalized existence reasoning;
  1216 
  1217 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1218 support accumulation of results, without applying any rules yet;
  1219 useful to collect intermediate results without explicit name
  1220 references, and for use with transitivity rules with more than 2
  1221 premises;
  1222 
  1223 * Isar/Pure: scalable support for case-analysis type proofs: new
  1224 'case' language element refers to local contexts symbolically, as
  1225 produced by certain proof methods; internally, case names are attached
  1226 to theorems as "tags";
  1227 
  1228 * Isar/Pure: theory command 'hide' removes declarations from
  1229 class/type/const name spaces;
  1230 
  1231 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1232 indicate potential overloading;
  1233 
  1234 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1235 
  1236 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1237 "{a,b,c}" instead of {a,b,c};
  1238 
  1239 * Isar/Pure now provides its own version of intro/elim/dest
  1240 attributes; useful for building new logics, but beware of confusion
  1241 with the version in Provers/classical;
  1242 
  1243 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1244 case name 'antecedent';
  1245 
  1246 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1247 to the current context is now done automatically);
  1248 
  1249 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1250 for definining proof methods in ML;
  1251 
  1252 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1253 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1254 most cases, one should have to change intro!! to intro? only);
  1255 replaced "delrule" by "rule del";
  1256 
  1257 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1258 'symmetric' attribute (the latter supercedes [RS sym]);
  1259 
  1260 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1261 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1262 well (including splits);
  1263 
  1264 * Isar/Provers: Simplifier and Classical methods now support all kind
  1265 of modifiers used in the past, including 'cong', 'iff', etc.
  1266 
  1267 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1268 of Simplifier and Classical reasoner);
  1269 
  1270 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1271 now support named cases; major packages (inductive, datatype, primrec,
  1272 recdef) support case names and properly name parameters;
  1273 
  1274 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1275 monotonicity conditions are extracted to be proven at end of
  1276 calculations;
  1277 
  1278 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1279 method anyway;
  1280 
  1281 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1282 split_if split_if_asm; datatype package provides theorems foo.splits =
  1283 foo.split foo.split_asm for each datatype;
  1284 
  1285 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1286 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1287 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1288 use "(cases (simplified))" method in proper proof texts);
  1289 
  1290 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1291 
  1292 * Isar: names of theorems etc. may be natural numbers as well;
  1293 
  1294 * Isar: 'pr' command: optional arguments for goals_limit and
  1295 ProofContext.prems_limit; no longer prints theory contexts, but only
  1296 proof states;
  1297 
  1298 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1299 additional print modes to be specified; e.g. "pr(latex)" will print
  1300 proof state according to the Isabelle LaTeX style;
  1301 
  1302 * Isar: improved support for emulating tactic scripts, including proof
  1303 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1304 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1305 (for HOL datatypes);
  1306 
  1307 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1308 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1309 'proof method scripts' have to be in depth-first order;
  1310 
  1311 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1312 
  1313 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1314 should instead use individual commands for printing items
  1315 (print_commands, print_methods etc.);
  1316 
  1317 * Isar: added 'nothing' --- the empty list of theorems;
  1318 
  1319 
  1320 *** HOL ***
  1321 
  1322 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1323 corresponding virtual machine and a specification of its bytecode
  1324 verifier and a lightweight bytecode verifier, including proofs of
  1325 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1326 Cornelia Pusch (see also the homepage of project Bali at
  1327 http://isabelle.in.tum.de/Bali/);
  1328 
  1329 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1330 Clemens Ballarin;
  1331 
  1332 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1333 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1334 Rasmussen;
  1335 
  1336 * HOL/Lattice: fundamental concepts of lattice theory and order
  1337 structures, including duals, properties of bounds versus algebraic
  1338 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1339 Theorem for complete lattices etc.; may also serve as a demonstration
  1340 for abstract algebraic reasoning using axiomatic type classes, and
  1341 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1342 
  1343 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1344 von Oheimb;
  1345 
  1346 * HOL/IMPP: extension of IMP with local variables and mutually
  1347 recursive procedures, by David von Oheimb;
  1348 
  1349 * HOL/Lambda: converted into new-style theory and document;
  1350 
  1351 * HOL/ex/Multiquote: example of multiple nested quotations and
  1352 anti-quotations -- basically a generalized version of de-Bruijn
  1353 representation; very useful in avoiding lifting of operations;
  1354 
  1355 * HOL/record: added general record equality rule to simpset; fixed
  1356 select-update simplification procedure to handle extended records as
  1357 well; admit "r" as field name;
  1358 
  1359 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1360 other numeric types and also as the identity of groups, rings, etc.;
  1361 
  1362 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1363 Types nat and int belong to this axclass;
  1364 
  1365 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1366    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1367    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1368   two terms #m*u and #n*u are replaced by #(m+n)*u
  1369     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1370   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1371     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1372 
  1373 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1374 powerful prover for predicate logic but knows nothing of clasets; see
  1375 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1376 
  1377 * HOL: new version of "case_tac" subsumes both boolean case split and
  1378 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1379 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1380 
  1381 * HOL: simplification no longer dives into case-expressions: only the
  1382 selector expression is simplified, but not the remaining arms; to
  1383 enable full simplification of case-expressions for datatype t, you may
  1384 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1385 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1386 
  1387 * HOL/recdef: the recursion equations generated by 'recdef' for
  1388 function 'f' are now called f.simps instead of f.rules; if all
  1389 termination conditions are proved automatically, these simplification
  1390 rules are added to the simpset, as in primrec; rules may be named
  1391 individually as well, resulting in a separate list of theorems for
  1392 each equation;
  1393 
  1394 * HOL/While is a new theory that provides a while-combinator. It
  1395 permits the definition of tail-recursive functions without the
  1396 provision of a termination measure. The latter is necessary once the
  1397 invariant proof rule for while is applied.
  1398 
  1399 * HOL: new (overloaded) notation for the set of elements below/above
  1400 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1401 
  1402 * HOL: theorems impI, allI, ballI bound as "strip";
  1403 
  1404 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1405 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1406 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1407 
  1408 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1409 
  1410 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1411 main HOL, but was unused);
  1412 
  1413 * HOL: fewer consts declared as global (e.g. have to refer to
  1414 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1415 
  1416 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1417 in case of overlap with user translations (e.g. judgements over
  1418 tuples); (note that the underlying logical represenation is still
  1419 bogus);
  1420 
  1421 
  1422 *** ZF ***
  1423 
  1424 * ZF: simplification automatically cancels common terms in arithmetic
  1425 expressions over nat and int;
  1426 
  1427 * ZF: new treatment of nat to minimize type-checking: all operators
  1428 coerce their operands to a natural number using the function natify,
  1429 making the algebraic laws unconditional;
  1430 
  1431 * ZF: as above, for int: operators coerce their operands to an integer
  1432 using the function intify;
  1433 
  1434 * ZF: the integer library now contains many of the usual laws for the
  1435 orderings, including $<=, and monotonicity laws for $+ and $*;
  1436 
  1437 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1438 simplification;
  1439 
  1440 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1441 to the simplifier and classical reasoner simultaneously;
  1442 
  1443 
  1444 *** General ***
  1445 
  1446 * Provers: blast_tac now handles actual object-logic rules as
  1447 assumptions; note that auto_tac uses blast_tac internally as well;
  1448 
  1449 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1450 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1451 
  1452 * Provers: delrules now handles destruct rules as well (no longer need
  1453 explicit make_elim);
  1454 
  1455 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1456   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1457 use instead the strong form,
  1458   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1459 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1460 from destruct-rules;
  1461 
  1462 * Provers: Simplifier.easy_setup provides a fast path to basic
  1463 Simplifier setup for new object-logics;
  1464 
  1465 * Pure: AST translation rules no longer require constant head on LHS;
  1466 
  1467 * Pure: improved name spaces: ambiguous output is qualified; support
  1468 for hiding of names;
  1469 
  1470 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1471 XSYMBOL_HOME; no longer need to do manual configuration in most
  1472 situations;
  1473 
  1474 * system: compression of ML heaps images may now be controlled via -c
  1475 option of isabelle and isatool usedir (currently only observed by
  1476 Poly/ML);
  1477 
  1478 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1479 useful for remote X11);
  1480 
  1481 * system: provide TAGS file for Isabelle sources;
  1482 
  1483 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1484 order;
  1485 
  1486 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1487 timing flag supersedes proof_timing and Toplevel.trace;
  1488 
  1489 * ML: new combinators |>> and |>>> for incremental transformations
  1490 with secondary results (e.g. certain theory extensions):
  1491 
  1492 * ML: PureThy.add_defs gets additional argument to indicate potential
  1493 overloading (usually false);
  1494 
  1495 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1496 results;
  1497 
  1498 
  1499 
  1500 New in Isabelle99 (October 1999)
  1501 --------------------------------
  1502 
  1503 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1504 
  1505 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1506 are no longer simplified.  (This allows the simplifier to unfold recursive
  1507 functional programs.)  To restore the old behaviour, declare
  1508 
  1509     Delcongs [if_weak_cong];
  1510 
  1511 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1512 complement;
  1513 
  1514 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1515 
  1516 * HOL/datatype: mutual_induct_tac no longer exists --
  1517   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1518 
  1519 * HOL/typedef: fixed type inference for representing set; type
  1520 arguments now have to occur explicitly on the rhs as type constraints;
  1521 
  1522 * ZF: The con_defs part of an inductive definition may no longer refer
  1523 to constants declared in the same theory;
  1524 
  1525 * HOL, ZF: the function mk_cases, generated by the inductive
  1526 definition package, has lost an argument.  To simplify its result, it
  1527 uses the default simpset instead of a supplied list of theorems.
  1528 
  1529 * HOL/List: the constructors of type list are now Nil and Cons;
  1530 
  1531 * Simplifier: the type of the infix ML functions
  1532         setSSolver addSSolver setSolver addSolver
  1533 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1534 for packaging solvers. A solver is created via
  1535         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1536 where the string argument is only a comment.
  1537 
  1538 
  1539 *** Proof tools ***
  1540 
  1541 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1542 decision procedure for linear arithmetic. Currently it is used for
  1543 types `nat', `int', and `real' in HOL (see below); it can, should and
  1544 will be instantiated for other types and logics as well.
  1545 
  1546 * The simplifier now accepts rewrite rules with flexible heads, eg
  1547      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1548   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1549   matching.
  1550 
  1551 
  1552 *** General ***
  1553 
  1554 * New Isabelle/Isar subsystem provides an alternative to traditional
  1555 tactical theorem proving; together with the ProofGeneral/isar user
  1556 interface it offers an interactive environment for developing human
  1557 readable proof documents (Isar == Intelligible semi-automated
  1558 reasoning); for further information see isatool doc isar-ref,
  1559 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1560 
  1561 * improved and simplified presentation of theories: better HTML markup
  1562 (including colors), graph views in several sizes; isatool usedir now
  1563 provides a proper interface for user theories (via -P option); actual
  1564 document preparation based on (PDF)LaTeX is available as well (for
  1565 new-style theories only); see isatool doc system for more information;
  1566 
  1567 * native support for Proof General, both for classic Isabelle and
  1568 Isabelle/Isar;
  1569 
  1570 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1571 using the graph browser tool;
  1572 
  1573 * Isabelle manuals now also available as PDF;
  1574 
  1575 * theory loader rewritten from scratch (may not be fully
  1576 bug-compatible); old loadpath variable has been replaced by show_path,
  1577 add_path, del_path, reset_path functions; new operations such as
  1578 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1579 isatool doc ref);
  1580 
  1581 * improved isatool install: option -k creates KDE application icon,
  1582 option -p DIR installs standalone binaries;
  1583 
  1584 * added ML_PLATFORM setting (useful for cross-platform installations);
  1585 more robust handling of platform specific ML images for SML/NJ;
  1586 
  1587 * the settings environment is now statically scoped, i.e. it is never
  1588 created again in sub-processes invoked from isabelle, isatool, or
  1589 Isabelle;
  1590 
  1591 * path element specification '~~' refers to '$ISABELLE_HOME';
  1592 
  1593 * in locales, the "assumes" and "defines" parts may be omitted if
  1594 empty;
  1595 
  1596 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1597 long arrows);
  1598 
  1599 * new print_mode "HTML";
  1600 
  1601 * new flag show_tags controls display of tags of theorems (which are
  1602 basically just comments that may be attached by some tools);
  1603 
  1604 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1605 mode and goal output format:
  1606 
  1607 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1608 244c244
  1609 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1610 ---
  1611 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1612 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1613 181c181
  1614 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1615 ---
  1616 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1617 
  1618 * function bind_thms stores lists of theorems (cf. bind_thm);
  1619 
  1620 * new shorthand tactics ftac, eatac, datac, fatac;
  1621 
  1622 * qed (and friends) now accept "" as result name; in that case the
  1623 theorem is not stored, but proper checks and presentation of the
  1624 result still apply;
  1625 
  1626 * theorem database now also indexes constants "Trueprop", "all",
  1627 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1628 
  1629 
  1630 *** HOL ***
  1631 
  1632 ** HOL arithmetic **
  1633 
  1634 * There are now decision procedures for linear arithmetic over nat and
  1635 int:
  1636 
  1637 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1638 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1639 are treated as atomic; subformulae not involving type `nat' or `int'
  1640 are ignored; quantified subformulae are ignored unless they are
  1641 positive universal or negative existential. The tactic has to be
  1642 invoked by hand and can be a little bit slow. In particular, the
  1643 running time is exponential in the number of occurrences of `min' and
  1644 `max', and `-' on `nat'.
  1645 
  1646 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1647 (negated) (in)equalities among the premises and the conclusion into
  1648 account (i.e. no compound formulae) and does not know about `min' and
  1649 `max', and `-' on `nat'. It is fast and is used automatically by the
  1650 simplifier.
  1651 
  1652 NB: At the moment, these decision procedures do not cope with mixed
  1653 nat/int formulae where the two parts interact, such as `m < n ==>
  1654 int(m) < int(n)'.
  1655 
  1656 * HOL/Numeral provides a generic theory of numerals (encoded
  1657 efficiently as bit strings); setup for types nat/int/real is in place;
  1658 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1659 int, existing theories and proof scripts may require a few additional
  1660 type constraints;
  1661 
  1662 * integer division and remainder can now be performed on constant
  1663 arguments;
  1664 
  1665 * many properties of integer multiplication, division and remainder
  1666 are now available;
  1667 
  1668 * An interface to the Stanford Validity Checker (SVC) is available through the
  1669 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1670 are proved automatically.  SVC must be installed separately, and its results
  1671 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1672 invocation of the underlying oracle).  For SVC see
  1673   http://verify.stanford.edu/SVC
  1674 
  1675 * IsaMakefile: the HOL-Real target now builds an actual image;
  1676 
  1677 
  1678 ** HOL misc **
  1679 
  1680 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1681 (in Isabelle/Isar) -- by Gertrud Bauer;
  1682 
  1683 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1684 analysis for assembly languages with subtypes;
  1685 
  1686 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1687 -- avoids syntactic ambiguities and treats state, transition, and
  1688 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1689 changed syntax and (many) tactics;
  1690 
  1691 * HOL/inductive: Now also handles more general introduction rules such
  1692   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1693   theorems are now maintained within the theory (maintained via the
  1694   "mono" attribute);
  1695 
  1696 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1697   (using function types) such as
  1698 
  1699   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1700 
  1701 * HOL/record: record_simproc (part of the default simpset) takes care
  1702 of selectors applied to updated records; record_split_tac is no longer
  1703 part of the default claset; update_defs may now be removed from the
  1704 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1705 
  1706   claset_ref () := claset() addSWrapper record_split_wrapper;
  1707   Delsimprocs [record_simproc]
  1708 
  1709 * HOL/typedef: fixed type inference for representing set; type
  1710 arguments now have to occur explicitly on the rhs as type constraints;
  1711 
  1712 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1713 names rather than an ML expression;
  1714 
  1715 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1716 supplied later.  Program schemes can be defined, such as
  1717     "While B C s = (if B s then While B C (C s) else s)"
  1718 where the well-founded relation can be chosen after B and C have been given.
  1719 
  1720 * HOL/List: the constructors of type list are now Nil and Cons;
  1721 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1722 course, ML tools referring to List.list.op # etc. have to be adapted;
  1723 
  1724 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1725 disabled by default; run isabelle with option -m HOL to get back to
  1726 the original Gordon/HOL-style output;
  1727 
  1728 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1729 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1730 
  1731 * HOL basic syntax simplified (more orthogonal): all variants of
  1732 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1733 Eps operator is provided as well: "SOME x. P[x]";
  1734 
  1735 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1736 
  1737 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1738 thus available for user theories;
  1739 
  1740 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1741 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1742 time;
  1743 
  1744 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1745 several times and then mp;
  1746 
  1747 
  1748 *** LK ***
  1749 
  1750 * the notation <<...>> is now available as a notation for sequences of
  1751 formulas;
  1752 
  1753 * the simplifier is now installed
  1754 
  1755 * the axiom system has been generalized (thanks to Soren Heilmann)
  1756 
  1757 * the classical reasoner now has a default rule database
  1758 
  1759 
  1760 *** ZF ***
  1761 
  1762 * new primrec section allows primitive recursive functions to be given
  1763 directly (as in HOL) over datatypes and the natural numbers;
  1764 
  1765 * new tactics induct_tac and exhaust_tac for induction (or case
  1766 analysis) over datatypes and the natural numbers;
  1767 
  1768 * the datatype declaration of type T now defines the recursor T_rec;
  1769 
  1770 * simplification automatically does freeness reasoning for datatype
  1771 constructors;
  1772 
  1773 * automatic type-inference, with AddTCs command to insert new
  1774 type-checking rules;
  1775 
  1776 * datatype introduction rules are now added as Safe Introduction rules
  1777 to the claset;
  1778 
  1779 * the syntax "if P then x else y" is now available in addition to
  1780 if(P,x,y);
  1781 
  1782 
  1783 *** Internal programming interfaces ***
  1784 
  1785 * tuned simplifier trace output; new flag debug_simp;
  1786 
  1787 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1788 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1789 
  1790 * AxClass.axclass_tac lost the theory argument;
  1791 
  1792 * tuned current_goals_markers semantics: begin / end goal avoids
  1793 printing empty lines;
  1794 
  1795 * removed prs and prs_fn hook, which was broken because it did not
  1796 include \n in its semantics, forcing writeln to add one
  1797 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1798 string -> unit if you really want to output text without newline;
  1799 
  1800 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1801 plain output, interface builders may have to enable 'isabelle_font'
  1802 mode to get Isabelle font glyphs as before;
  1803 
  1804 * refined token_translation interface; INCOMPATIBILITY: output length
  1805 now of type real instead of int;
  1806 
  1807 * theory loader actions may be traced via new ThyInfo.add_hook
  1808 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1809 your own database of information attached to *whole* theories -- as
  1810 opposed to intra-theory data slots offered via TheoryDataFun;
  1811 
  1812 * proper handling of dangling sort hypotheses (at last!);
  1813 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1814 extra sort hypotheses that can be witnessed from the type signature;
  1815 the force_strip_shyps flag is gone, any remaining shyps are simply
  1816 left in the theorem (with a warning issued by strip_shyps_warning);
  1817 
  1818 
  1819 
  1820 New in Isabelle98-1 (October 1998)
  1821 ----------------------------------
  1822 
  1823 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1824 
  1825 * several changes of automated proof tools;
  1826 
  1827 * HOL: major changes to the inductive and datatype packages, including
  1828 some minor incompatibilities of theory syntax;
  1829 
  1830 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1831 called `inj_on';
  1832 
  1833 * HOL: removed duplicate thms in Arith:
  1834   less_imp_add_less  should be replaced by  trans_less_add1
  1835   le_imp_add_le      should be replaced by  trans_le_add1
  1836 
  1837 * HOL: unary minus is now overloaded (new type constraints may be
  1838 required);
  1839 
  1840 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1841 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1842 now taken as an integer constant.
  1843 
  1844 * Pure: ML function 'theory_of' renamed to 'theory';
  1845 
  1846 
  1847 *** Proof tools ***
  1848 
  1849 * Simplifier:
  1850   1. Asm_full_simp_tac is now more aggressive.
  1851      1. It will sometimes reorient premises if that increases their power to
  1852         simplify.
  1853      2. It does no longer proceed strictly from left to right but may also
  1854         rotate premises to achieve further simplification.
  1855      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1856      old Asm_full_simp_tac in that it does not rotate premises.
  1857   2. The simplifier now knows a little bit about nat-arithmetic.
  1858 
  1859 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1860 allows for selected deletion of wrappers, by introduction of names for
  1861 wrapper functionals.  This implies that addbefore, addSbefore,
  1862 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1863 and that adding two tactics with the same name overwrites the first
  1864 one (emitting a warning).
  1865   type wrapper = (int -> tactic) -> (int -> tactic)
  1866   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1867   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1868   delWrapper, delSWrapper: claset *  string            -> claset
  1869   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1870 
  1871 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1872 semantics; addbefore now affects only the unsafe part of step_tac
  1873 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1874 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1875 by Force_tac;
  1876 
  1877 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1878 compWrapper; added safe wrapper (and access functions for it);
  1879 
  1880 * HOL/split_all_tac is now much faster and fails if there is nothing
  1881 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1882 and the names of the automatically generated variables have changed.
  1883 split_all_tac has moved within claset() from unsafe wrappers to safe
  1884 wrappers, which means that !!-bound variables are split much more
  1885 aggressively, and safe_tac and clarify_tac now split such variables.
  1886 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1887 Note: the same holds for record_split_tac, which does the job of
  1888 split_all_tac for record fields.
  1889 
  1890 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1891 permanently to the default simpset using Addsplits just like
  1892 Addsimps. They can be removed via Delsplits just like
  1893 Delsimps. Lower-case versions are also available.
  1894 
  1895 * HOL/Simplifier: The rule split_if is now part of the default
  1896 simpset. This means that the simplifier will eliminate all occurrences
  1897 of if-then-else in the conclusion of a goal. To prevent this, you can
  1898 either remove split_if completely from the default simpset by
  1899 `Delsplits [split_if]' or remove it in a specific call of the
  1900 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1901 other case splitting rules to/from the default simpset: every datatype
  1902 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1903 t is the name of the datatype).
  1904 
  1905 * Classical reasoner / Simplifier combination: new force_tac (and
  1906 derivatives Force_tac, force) combines rewriting and classical
  1907 reasoning (and whatever other tools) similarly to auto_tac, but is
  1908 aimed to solve the given subgoal completely.
  1909 
  1910 
  1911 *** General ***
  1912 
  1913 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1914 and `goalw': the theory is no longer needed as an explicit argument -
  1915 the current theory context is used; assumptions are no longer returned
  1916 at the ML-level unless one of them starts with ==> or !!; it is
  1917 recommended to convert to these new commands using isatool fixgoal
  1918 (backup your sources first!);
  1919 
  1920 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1921 the current theory context, and 'theory' to lookup stored theories;
  1922 
  1923 * new theory section 'locale' for declaring constants, assumptions and
  1924 definitions that have local scope;
  1925 
  1926 * new theory section 'nonterminals' for purely syntactic types;
  1927 
  1928 * new theory section 'setup' for generic ML setup functions
  1929 (e.g. package initialization);
  1930 
  1931 * the distribution now includes Isabelle icons: see
  1932 lib/logo/isabelle-{small,tiny}.xpm;
  1933 
  1934 * isatool install - install binaries with absolute references to
  1935 ISABELLE_HOME/bin;
  1936 
  1937 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1938 
  1939 * print mode 'emacs' reserved for Isamode;
  1940 
  1941 * support multiple print (ast) translations per constant name;
  1942 
  1943 * theorems involving oracles are now printed with a suffixed [!];
  1944 
  1945 
  1946 *** HOL ***
  1947 
  1948 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1949 
  1950 * HOL/inductive package reorganized and improved: now supports mutual
  1951 definitions such as
  1952 
  1953   inductive EVEN ODD
  1954     intrs
  1955       null "0 : EVEN"
  1956       oddI "n : EVEN ==> Suc n : ODD"
  1957       evenI "n : ODD ==> Suc n : EVEN"
  1958 
  1959 new theorem list "elims" contains an elimination rule for each of the
  1960 recursive sets; inductive definitions now handle disjunctive premises
  1961 correctly (also ZF);
  1962 
  1963 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1964 "mutual_induct" no longer exists - the induction rule is always
  1965 contained in "induct";
  1966 
  1967 
  1968 * HOL/datatype package re-implemented and greatly improved: now
  1969 supports mutually recursive datatypes such as
  1970 
  1971   datatype
  1972     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1973             | SUM ('a aexp) ('a aexp)
  1974             | DIFF ('a aexp) ('a aexp)
  1975             | NUM 'a
  1976   and
  1977     'a bexp = LESS ('a aexp) ('a aexp)
  1978             | AND ('a bexp) ('a bexp)
  1979             | OR ('a bexp) ('a bexp)
  1980 
  1981 as well as indirectly recursive datatypes such as
  1982 
  1983   datatype
  1984     ('a, 'b) term = Var 'a
  1985                   | App 'b ((('a, 'b) term) list)
  1986 
  1987 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1988 induction on mutually / indirectly recursive datatypes.
  1989 
  1990 Primrec equations are now stored in theory and can be accessed via
  1991 <function_name>.simps.
  1992 
  1993 INCOMPATIBILITIES:
  1994 
  1995   - Theories using datatypes must now have theory Datatype as an
  1996     ancestor.
  1997   - The specific <typename>.induct_tac no longer exists - use the
  1998     generic induct_tac instead.
  1999   - natE has been renamed to nat.exhaust - use exhaust_tac
  2000     instead of res_inst_tac ... natE. Note that the variable
  2001     names in nat.exhaust differ from the names in natE, this
  2002     may cause some "fragile" proofs to fail.
  2003   - The theorems split_<typename>_case and split_<typename>_case_asm
  2004     have been renamed to <typename>.split and <typename>.split_asm.
  2005   - Since default sorts of type variables are now handled correctly,
  2006     some datatype definitions may have to be annotated with explicit
  2007     sort constraints.
  2008   - Primrec definitions no longer require function name and type
  2009     of recursive argument.
  2010 
  2011 Consider using isatool fixdatatype to adapt your theories and proof
  2012 scripts to the new package (backup your sources first!).
  2013 
  2014 
  2015 * HOL/record package: considerably improved implementation; now
  2016 includes concrete syntax for record types, terms, updates; theorems
  2017 for surjective pairing and splitting !!-bound record variables; proof
  2018 support is as follows:
  2019 
  2020   1) standard conversions (selectors or updates applied to record
  2021 constructor terms) are part of the standard simpset;
  2022 
  2023   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2024 made part of standard simpset and claset via addIffs;
  2025 
  2026   3) a tactic for record field splitting (record_split_tac) is part of
  2027 the standard claset (addSWrapper);
  2028 
  2029 To get a better idea about these rules you may retrieve them via
  2030 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2031 the name of your record type.
  2032 
  2033 The split tactic 3) conceptually simplifies by the following rule:
  2034 
  2035   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2036 
  2037 Thus any record variable that is bound by meta-all will automatically
  2038 blow up into some record constructor term, consequently the
  2039 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2040 solve record problems automatically.
  2041 
  2042 
  2043 * reorganized the main HOL image: HOL/Integ and String loaded by
  2044 default; theory Main includes everything;
  2045 
  2046 * automatic simplification of integer sums and comparisons, using cancellation;
  2047 
  2048 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2049 
  2050 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2051 
  2052 * many new identities for unions, intersections, set difference, etc.;
  2053 
  2054 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2055 called split_if, split_split, split_sum_case and split_nat_case (to go
  2056 with add/delsplits);
  2057 
  2058 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2059 (?x::unit) = (); this is made part of the default simpset, which COULD
  2060 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2061 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2062 unit_abs_eta_conv is added in order to counter the effect of
  2063 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2064 %u.f();
  2065 
  2066 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2067 makes more sense);
  2068 
  2069 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2070   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2071   disjointness reasoning but breaking a few old proofs.
  2072 
  2073 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2074 to 'converse' from 'inverse' (for compatibility with ZF and some
  2075 literature);
  2076 
  2077 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2078 the well-founded relation;
  2079 
  2080 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2081     Compl A.  The "Compl" syntax remains available as input syntax for this
  2082     release ONLY.
  2083 
  2084 * HOL/Update: new theory of function updates:
  2085     f(a:=b) == %x. if x=a then b else f x
  2086 may also be iterated as in f(a:=b,c:=d,...);
  2087 
  2088 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2089 
  2090 * HOL/List:
  2091   - new function list_update written xs[i:=v] that updates the i-th
  2092     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2093   - new function `upt' written [i..j(] which generates the list
  2094     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2095     bound write [i..j], which is a shorthand for [i..j+1(].
  2096   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2097 
  2098 * HOL/Arith:
  2099   - removed 'pred' (predecessor) function;
  2100   - generalized some theorems about n-1;
  2101   - many new laws about "div" and "mod";
  2102   - new laws about greatest common divisors (see theory ex/Primes);
  2103 
  2104 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2105 instead of "inverse";
  2106 
  2107 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2108   of the multiset ordering;
  2109 
  2110 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2111   (not included by default);
  2112 
  2113 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2114 
  2115 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2116   programs, i.e. different program variables may have different types.
  2117 
  2118 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2119   [previously, this check worked only if the rewrite rule was unconditional]
  2120   Now rew can involve either definitions or equalities (either == or =).
  2121 
  2122 
  2123 *** ZF ***
  2124 
  2125 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2126   only the theorems proved on ZF.ML;
  2127 
  2128 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2129   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2130   disjointness reasoning but breaking a few old proofs.
  2131 
  2132 * ZF/Update: new theory of function updates
  2133     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2134   may also be iterated as in f(a:=b,c:=d,...);
  2135 
  2136 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2137 
  2138 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2139   [previously, this check worked only if the rewrite rule was unconditional]
  2140   Now rew can involve either definitions or equalities (either == or =).
  2141 
  2142 * case_tac provided for compatibility with HOL
  2143     (like the old excluded_middle_tac, but with subgoals swapped)
  2144 
  2145 
  2146 *** Internal programming interfaces ***
  2147 
  2148 * Pure: several new basic modules made available for general use, see
  2149 also src/Pure/README;
  2150 
  2151 * improved the theory data mechanism to support encapsulation (data
  2152 kind name replaced by private Object.kind, acting as authorization
  2153 key); new type-safe user interface via functor TheoryDataFun; generic
  2154 print_data function becomes basically useless;
  2155 
  2156 * removed global_names compatibility flag -- all theory declarations
  2157 are qualified by default;
  2158 
  2159 * module Pure/Syntax now offers quote / antiquote translation
  2160 functions (useful for Hoare logic etc. with implicit dependencies);
  2161 see HOL/ex/Antiquote for an example use;
  2162 
  2163 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2164 cterm -> thm;
  2165 
  2166 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2167 subgoal;
  2168 
  2169 * Display.print_goals function moved to Locale.print_goals;
  2170 
  2171 * standard print function for goals supports current_goals_markers
  2172 variable for marking begin of proof, end of proof, start of goal; the
  2173 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2174 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2175 for example;
  2176 
  2177 
  2178 
  2179 New in Isabelle98 (January 1998)
  2180 --------------------------------
  2181 
  2182 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2183 
  2184 * changed lexical syntax of terms / types: dots made part of long
  2185 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2186 
  2187 * simpset (and claset) reference variable replaced by functions
  2188 simpset / simpset_ref;
  2189 
  2190 * no longer supports theory aliases (via merge) and non-trivial
  2191 implicit merge of thms' signatures;
  2192 
  2193 * most internal names of constants changed due to qualified names;
  2194 
  2195 * changed Pure/Sequence interface (see Pure/seq.ML);
  2196 
  2197 
  2198 *** General Changes ***
  2199 
  2200 * hierachically structured name spaces (for consts, types, axms, thms
  2201 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2202 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2203 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2204 long_names for fully qualified output names; NOTE: ML programs
  2205 (special tactics, packages etc.) referring to internal names may have
  2206 to be adapted to cope with fully qualified names; in case of severe
  2207 backward campatibility problems try setting 'global_names' at compile
  2208 time to have enrything declared within a flat name space; one may also
  2209 fine tune name declarations in theories via the 'global' and 'local'
  2210 section;
  2211 
  2212 * reimplemented the implicit simpset and claset using the new anytype
  2213 data filed in signatures; references simpset:simpset ref etc. are
  2214 replaced by functions simpset:unit->simpset and
  2215 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2216 to patch your ML files accordingly;
  2217 
  2218 * HTML output now includes theory graph data for display with Java
  2219 applet or isatool browser; data generated automatically via isatool
  2220 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2221 
  2222 * defs may now be conditional; improved rewrite_goals_tac to handle
  2223 conditional equations;
  2224 
  2225 * defs now admits additional type arguments, using TYPE('a) syntax;
  2226 
  2227 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2228 creates a new theory node; implicit merge of thms' signatures is
  2229 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2230 transfer:theory->thm->thm in (rare) cases;
  2231 
  2232 * improved handling of draft signatures / theories; draft thms (and
  2233 ctyps, cterms) are automatically promoted to real ones;
  2234 
  2235 * slightly changed interfaces for oracles: admit many per theory, named
  2236 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2237 
  2238 * print_goals: optional output of const types (set show_consts and
  2239 show_types);
  2240 
  2241 * improved output of warnings (###) and errors (***);
  2242 
  2243 * subgoal_tac displays a warning if the new subgoal has type variables;
  2244 
  2245 * removed old README and Makefiles;
  2246 
  2247 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2248 
  2249 * removed obsolete init_pps and init_database;
  2250 
  2251 * deleted the obsolete tactical STATE, which was declared by
  2252     fun STATE tacfun st = tacfun st st;
  2253 
  2254 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2255 (which abbreviates $HOME);
  2256 
  2257 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2258 use isatool fixseq to adapt your ML programs (this works for fully
  2259 qualified references to the Sequence structure only!);
  2260 
  2261 * use_thy no longer requires writable current directory; it always
  2262 reloads .ML *and* .thy file, if either one is out of date;
  2263 
  2264 
  2265 *** Classical Reasoner ***
  2266 
  2267 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2268 tactics that use classical reasoning to simplify a subgoal without
  2269 splitting it into several subgoals;
  2270 
  2271 * Safe_tac: like safe_tac but uses the default claset;
  2272 
  2273 
  2274 *** Simplifier ***
  2275 
  2276 * added simplification meta rules:
  2277     (asm_)(full_)simplify: simpset -> thm -> thm;
  2278 
  2279 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2280 logics (again);
  2281 
  2282 * added prems argument to simplification procedures;
  2283 
  2284 * HOL, FOL, ZF: added infix function `addsplits':
  2285   instead of `<simpset> setloop (split_tac <thms>)'
  2286   you can simply write `<simpset> addsplits <thms>'
  2287 
  2288 
  2289 *** Syntax ***
  2290 
  2291 * TYPE('a) syntax for type reflection terms;
  2292 
  2293 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2294 
  2295 * pretty printer: changed order of mixfix annotation preference (again!);
  2296 
  2297 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2298 
  2299 
  2300 *** HOL ***
  2301 
  2302 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2303   with `addloop' of the simplifier to faciliate case splitting in premises.
  2304 
  2305 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2306 
  2307 * HOL/Auth: new protocol proofs including some for the Internet
  2308   protocol TLS;
  2309 
  2310 * HOL/Map: new theory of `maps' a la VDM;
  2311 
  2312 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2313 cancelling out common nat summands from =, <, <= (in)equalities, or
  2314 differences; simplification procedures nat_cancel_factor for
  2315 cancelling common factor from =, <, <= (in)equalities over natural
  2316 sums; nat_cancel contains both kinds of procedures, it is installed by
  2317 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2318 
  2319 * HOL/simplifier: terms of the form
  2320   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2321   are rewritten to
  2322   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2323   and those of the form
  2324   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2325   are rewritten to
  2326   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2327 
  2328 * HOL/datatype
  2329   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2330 
  2331   P(t_case f1 ... fn x) =
  2332      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2333         ...
  2334        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2335      )
  2336 
  2337   and a theorem `split_t_case_asm' of the form
  2338 
  2339   P(t_case f1 ... fn x) =
  2340     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2341         ...
  2342        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2343      )
  2344   which can be added to a simpset via `addsplits'. The existing theorems
  2345   expand_list_case and expand_option_case have been renamed to
  2346   split_list_case and split_option_case.
  2347 
  2348 * HOL/Arithmetic:
  2349   - `pred n' is automatically converted to `n-1'.
  2350     Users are strongly encouraged not to use `pred' any longer,
  2351     because it will disappear altogether at some point.
  2352   - Users are strongly encouraged to write "0 < n" rather than
  2353     "n ~= 0". Theorems and proof tools have been modified towards this
  2354     `standard'.
  2355 
  2356 * HOL/Lists:
  2357   the function "set_of_list" has been renamed "set" (and its theorems too);
  2358   the function "nth" now takes its arguments in the reverse order and
  2359   has acquired the infix notation "!" as in "xs!n".
  2360 
  2361 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2362 
  2363 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2364   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2365 
  2366 * HOL/record: extensible records with schematic structural subtyping
  2367 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2368 still lacks various theorems and concrete record syntax;
  2369 
  2370 
  2371 *** HOLCF ***
  2372 
  2373 * removed "axioms" and "generated by" sections;
  2374 
  2375 * replaced "ops" section by extended "consts" section, which is capable of
  2376   handling the continuous function space "->" directly;
  2377 
  2378 * domain package:
  2379   . proves theorems immediately and stores them in the theory,
  2380   . creates hierachical name space,
  2381   . now uses normal mixfix annotations (instead of cinfix...),
  2382   . minor changes to some names and values (for consistency),
  2383   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2384   . separator between mutual domain defs: changed "," to "and",
  2385   . improved handling of sort constraints;  now they have to
  2386     appear on the left-hand side of the equations only;
  2387 
  2388 * fixed LAM <x,y,zs>.b syntax;
  2389 
  2390 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2391 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2392 
  2393 
  2394 *** FOL and ZF ***
  2395 
  2396 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2397   with `addloop' of the simplifier to faciliate case splitting in premises.
  2398 
  2399 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2400 in HOL, they strip ALL and --> from proved theorems;
  2401 
  2402 
  2403 
  2404 New in Isabelle94-8 (May 1997)
  2405 ------------------------------
  2406 
  2407 *** General Changes ***
  2408 
  2409 * new utilities to build / run / maintain Isabelle etc. (in parts
  2410 still somewhat experimental); old Makefiles etc. still functional;
  2411 
  2412 * new 'Isabelle System Manual';
  2413 
  2414 * INSTALL text, together with ./configure and ./build scripts;
  2415 
  2416 * reimplemented type inference for greater efficiency, better error
  2417 messages and clean internal interface;
  2418 
  2419 * prlim command for dealing with lots of subgoals (an easier way of
  2420 setting goals_limit);
  2421 
  2422 
  2423 *** Syntax ***
  2424 
  2425 * supports alternative (named) syntax tables (parser and pretty
  2426 printer); internal interface is provided by add_modesyntax(_i);
  2427 
  2428 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2429 be used in conjunction with the Isabelle symbol font; uses the
  2430 "symbols" syntax table;
  2431 
  2432 * added token_translation interface (may translate name tokens in
  2433 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2434 the current print_mode); IMPORTANT: user print translation functions
  2435 are responsible for marking newly introduced bounds
  2436 (Syntax.mark_boundT);
  2437 
  2438 * token translations for modes "xterm" and "xterm_color" that display
  2439 names in bold, underline etc. or colors (which requires a color
  2440 version of xterm);
  2441 
  2442 * infixes may now be declared with names independent of their syntax;
  2443 
  2444 * added typed_print_translation (like print_translation, but may
  2445 access type of constant);
  2446 
  2447 
  2448 *** Classical Reasoner ***
  2449 
  2450 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2451 some limitations.  Blast_tac...
  2452   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2453   + ignores elimination rules that don't have the correct format
  2454         (the conclusion MUST be a formula variable)
  2455   + ignores types, which can make HOL proofs fail
  2456   + rules must not require higher-order unification, e.g. apply_type in ZF
  2457     [message "Function Var's argument not a bound variable" relates to this]
  2458   + its proof strategy is more general but can actually be slower
  2459 
  2460 * substitution with equality assumptions no longer permutes other
  2461 assumptions;
  2462 
  2463 * minor changes in semantics of addafter (now called addaltern); renamed
  2464 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2465 (and access functions for it);
  2466 
  2467 * improved combination of classical reasoner and simplifier:
  2468   + functions for handling clasimpsets
  2469   + improvement of addss: now the simplifier is called _after_ the
  2470     safe steps.
  2471   + safe variant of addss called addSss: uses safe simplifications
  2472     _during_ the safe steps. It is more complete as it allows multiple
  2473     instantiations of unknowns (e.g. with slow_tac).
  2474 
  2475 *** Simplifier ***
  2476 
  2477 * added interface for simplification procedures (functions that
  2478 produce *proven* rewrite rules on the fly, depending on current
  2479 redex);
  2480 
  2481 * ordering on terms as parameter (used for ordered rewriting);
  2482 
  2483 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2484 
  2485 * the solver is now split into a safe and an unsafe part.
  2486 This should be invisible for the normal user, except that the
  2487 functions setsolver and addsolver have been renamed to setSolver and
  2488 addSolver; added safe_asm_full_simp_tac;
  2489 
  2490 
  2491 *** HOL ***
  2492 
  2493 * a generic induction tactic `induct_tac' which works for all datatypes and
  2494 also for type `nat';
  2495 
  2496 * a generic case distinction tactic `exhaust_tac' which works for all
  2497 datatypes and also for type `nat';
  2498 
  2499 * each datatype comes with a function `size';
  2500 
  2501 * patterns in case expressions allow tuple patterns as arguments to
  2502 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2503 
  2504 * primrec now also works with type nat;
  2505 
  2506 * recdef: a new declaration form, allows general recursive functions to be
  2507 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2508 
  2509 * the constant for negation has been renamed from "not" to "Not" to
  2510 harmonize with FOL, ZF, LK, etc.;
  2511 
  2512 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2513 infinite lists;
  2514 
  2515 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2516 
  2517 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2518 problems in commutative rings, using axiomatic type classes for + and *;
  2519 
  2520 * more examples in HOL/MiniML and HOL/Auth;
  2521 
  2522 * more default rewrite rules for quantifiers, union/intersection;
  2523 
  2524 * a new constant `arbitrary == @x.False';
  2525 
  2526 * HOLCF/IOA replaces old HOL/IOA;
  2527 
  2528 * HOLCF changes: derived all rules and arities
  2529   + axiomatic type classes instead of classes
  2530   + typedef instead of faking type definitions
  2531   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2532   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2533   + eliminated the types void, one, tr
  2534   + use unit lift and bool lift (with translations) instead of one and tr
  2535   + eliminated blift from Lift3.thy (use Def instead of blift)
  2536   all eliminated rules are derived as theorems --> no visible changes ;
  2537 
  2538 
  2539 *** ZF ***
  2540 
  2541 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2542 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2543 as ZF_cs addSIs [equalityI];
  2544 
  2545 
  2546 
  2547 New in Isabelle94-7 (November 96)
  2548 ---------------------------------
  2549 
  2550 * allowing negative levels (as offsets) in prlev and choplev;
  2551 
  2552 * super-linear speedup for large simplifications;
  2553 
  2554 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2555 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2556 FAIL); can suppress it using the command Delsimps (ex_simps @
  2557 all_simps); De Morgan laws are also now included, by default;
  2558 
  2559 * improved printing of ==>  :  ~:
  2560 
  2561 * new object-logic "Sequents" adds linear logic, while replacing LK
  2562 and Modal (thanks to Sara Kalvala);
  2563 
  2564 * HOL/Auth: correctness proofs for authentication protocols;
  2565 
  2566 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2567 examples on HOL/Auth);
  2568 
  2569 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2570 the rewriter and classical reasoner simultaneously;
  2571 
  2572 * function uresult no longer returns theorems in "standard" format;
  2573 regain previous version by: val uresult = standard o uresult;
  2574 
  2575 
  2576 
  2577 New in Isabelle94-6
  2578 -------------------
  2579 
  2580 * oracles -- these establish an interface between Isabelle and trusted
  2581 external reasoners, which may deliver results as theorems;
  2582 
  2583 * proof objects (in particular record all uses of oracles);
  2584 
  2585 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2586 
  2587 * "constdefs" section in theory files;
  2588 
  2589 * "primrec" section (HOL) no longer requires names;
  2590 
  2591 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2592 
  2593 
  2594 
  2595 New in Isabelle94-5
  2596 -------------------
  2597 
  2598 * reduced space requirements;
  2599 
  2600 * automatic HTML generation from theories;
  2601 
  2602 * theory files no longer require "..." (quotes) around most types;
  2603 
  2604 * new examples, including two proofs of the Church-Rosser theorem;
  2605 
  2606 * non-curried (1994) version of HOL is no longer distributed;
  2607 
  2608 
  2609 
  2610 New in Isabelle94-4
  2611 -------------------
  2612 
  2613 * greatly reduced space requirements;
  2614 
  2615 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2616 
  2617 * searchable theorem database (see the section "Retrieving theorems" on
  2618 page 8 of the Reference Manual);
  2619 
  2620 * new examples, including Grabczewski's monumental case study of the
  2621 Axiom of Choice;
  2622 
  2623 * The previous version of HOL renamed to Old_HOL;
  2624 
  2625 * The new version of HOL (previously called CHOL) uses a curried syntax
  2626 for functions.  Application looks like f a b instead of f(a,b);
  2627 
  2628 * Mutually recursive inductive definitions finally work in HOL;
  2629 
  2630 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2631 translates to the operator "split";
  2632 
  2633 
  2634 
  2635 New in Isabelle94-3
  2636 -------------------
  2637 
  2638 * new infix operator, addss, allowing the classical reasoner to
  2639 perform simplification at each step of its search.  Example:
  2640         fast_tac (cs addss ss)
  2641 
  2642 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2643 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2644 look like (a,b) instead of <a,b>;
  2645 
  2646 * PLEASE NOTE: CHOL will eventually replace HOL!
  2647 
  2648 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2649 It translates to the operator "split".  A new theory of integers is available;
  2650 
  2651 * In ZF, integer numerals now denote two's-complement binary integers.
  2652 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2653 
  2654 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2655 of the Axiom of Choice;
  2656 
  2657 
  2658 
  2659 New in Isabelle94-2
  2660 -------------------
  2661 
  2662 * Significantly faster resolution;
  2663 
  2664 * the different sections in a .thy file can now be mixed and repeated
  2665 freely;
  2666 
  2667 * Database of theorems for FOL, HOL and ZF.  New
  2668 commands including qed, qed_goal and bind_thm store theorems in the database.
  2669 
  2670 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2671 a given theory (thms_of), or find out what theory a theorem was proved in
  2672 (theory_of_thm);
  2673 
  2674 * Bugs fixed in the inductive definition and datatype packages;
  2675 
  2676 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2677 and HOL_dup_cs obsolete;
  2678 
  2679 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2680 have been removed;
  2681 
  2682 * Simpler definition of function space in ZF;
  2683 
  2684 * new results about cardinal and ordinal arithmetic in ZF;
  2685 
  2686 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2687 types;
  2688 
  2689 
  2690 $Id$