NEWS
author wenzelm
Mon May 10 19:27:45 2004 +0200 (2004-05-10)
changeset 14731 5670fc027a3b
parent 14709 d01983034ded
child 14795 b702848de41f
permissions -rw-r--r--
Pure: nested comments in inner syntax;
     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 
    37 *** HOL ***
    38 
    39 * HOL/record: reimplementation of records. Improved scalability for
    40   records with many fields, avoiding performance problems for type
    41   inference. Records are no longer composed of nested field types, but
    42   of nested extension types. Therefore the record type only grows
    43   linear in the number of extensions and not in the number of fields.
    44   The top-level (users) view on records is preserved.  Potential
    45   INCOMPATIBILITY only in strange cases, where the theory depends on
    46   the old record representation. The type generated for a record is
    47   called <record_name>_ext_type.
    48 
    49 * Simplifier: "record_upd_simproc" for simplification of multiple
    50   record updates enabled by default.  INCOMPATIBILITY: old proofs
    51   break occasionally, since simplification is more powerful by
    52   default.
    53 
    54 
    55 *** HOLCF ***
    56 
    57 * HOLCF: discontinued special version of 'constdefs' (which used to
    58   support continuous functions) in favor of the general Pure one with
    59   full type-inference.
    60 
    61 
    62 
    63 New in Isabelle2004 (April 2004)
    64 --------------------------------
    65 
    66 *** General ***
    67 
    68 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    69   Replaces linorder.ML.
    70 
    71 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
    72   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
    73   (\<a>...\<z>), are now considered normal letters, and can therefore
    74   be used anywhere where an ASCII letter (a...zA...Z) has until
    75   now. COMPATIBILITY: This obviously changes the parsing of some
    76   terms, especially where a symbol has been used as a binder, say
    77   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    78   as an identifier.  Fix it by inserting a space around former
    79   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    80   existing theory and ML files.
    81 
    82 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    83 
    84 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
    85   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
    86   a normal (but invisible) letter. For multiple letter subscripts repeat
    87   \<^isub> like this: x\<^isub>1\<^isub>2.
    88 
    89 * Pure: There are now sub-/superscripts that can span more than one
    90   character. Text between \<^bsub> and \<^esub> is set in subscript in
    91   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
    92   superscript. The new control characters are not identifier parts.
    93 
    94 * Pure: Control-symbols of the form \<^raw:...> will literally print the
    95   content of "..." to the latex file instead of \isacntrl... . The "..."
    96   may consist of any printable characters excluding the end bracket >.
    97 
    98 * Pure: Using new Isar command "finalconsts" (or the ML functions
    99   Theory.add_finals or Theory.add_finals_i) it is now possible to
   100   declare constants "final", which prevents their being given a definition
   101   later.  It is useful for constants whose behaviour is fixed axiomatically
   102   rather than definitionally, such as the meta-logic connectives.
   103 
   104 * Pure: 'instance' now handles general arities with general sorts
   105   (i.e. intersections of classes),
   106 
   107 * Presentation: generated HTML now uses a CSS style sheet to make layout
   108   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   109   It can be changed to alter the colors/layout of generated pages.
   110 
   111 
   112 *** Isar ***
   113 
   114 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   115   cut_tac, subgoal_tac and thin_tac:
   116   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   117     locales are no longer forced to write Isar proof scripts.
   118     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   119     emulations.
   120   - INCOMPATIBILITY: names of variables to be instantiated may no
   121     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   122     This is consistent with the instantiation attribute "where".
   123 
   124 * Attributes "where" and "of":
   125   - Now take type variables of instantiated theorem into account when reading
   126     the instantiation string.  This fixes a bug that caused instantiated
   127     theorems to have too special types in some circumstances.
   128   - "where" permits explicit instantiations of type variables.
   129 
   130 * Calculation commands "moreover" and "also" no longer interfere with
   131   current facts ("this"), admitting arbitrary combinations with "then"
   132   and derived forms.
   133 
   134 * Locales:
   135   - Goal statements involving the context element "includes" no longer
   136     generate theorems with internal delta predicates (those ending on
   137     "_axioms") in the premise.
   138     Resolve particular premise with <locale>.intro to obtain old form.
   139   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   140     specification and "includes" elements in goal statement.
   141   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   142     [intro?] and [elim?] (respectively) by default.
   143   - Experimental command for instantiation of locales in proof contexts:
   144         instantiate <label>[<attrs>]: <loc>
   145     Instantiates locale <loc> and adds all its theorems to the current context
   146     taking into account their attributes.  Label and attrs are optional
   147     modifiers, like in theorem declarations.  If present, names of
   148     instantiated theorems are qualified with <label>, and the attributes
   149     <attrs> are applied after any attributes these theorems might have already.
   150       If the locale has assumptions, a chained fact of the form
   151     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   152     are derived.  The command does not support old-style locales declared
   153     with "locale (open)".
   154       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   155 
   156 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   157   (Isar) contexts.
   158 
   159 
   160 *** HOL ***
   161 
   162 * Proof import: new image HOL4 contains the imported library from
   163   the HOL4 system with about 2500 theorems. It is imported by
   164   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   165   can be used like any other Isabelle image.  See
   166   HOL/Import/HOL/README for more information.
   167 
   168 * Simplifier:
   169   - Much improved handling of linear and partial orders.
   170     Reasoners for linear and partial orders are set up for type classes
   171     "linorder" and "order" respectively, and are added to the default simpset
   172     as solvers.  This means that the simplifier can build transitivity chains
   173     to solve goals from the assumptions.
   174   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   175     of blast or auto after simplification become unnecessary because the goal
   176     is solved by simplification already.
   177 
   178 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   179     all proved in axiomatic type classes for semirings, rings and fields.
   180 
   181 * Numerics:
   182   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   183     now formalized using the Ring_and_Field theory mentioned above.
   184   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   185     than before, because now they are set up once in a generic manner.
   186   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   187     Look for the general versions in Ring_and_Field (and Power if they concern
   188     exponentiation).
   189 
   190 * Type "rat" of the rational numbers is now available in HOL-Complex.
   191 
   192 * Records:
   193   - Record types are now by default printed with their type abbreviation
   194     instead of the list of all field types. This can be configured via
   195     the reference "print_record_type_abbr".
   196   - Simproc "record_upd_simproc" for simplification of multiple updates added
   197     (not enabled by default).
   198   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   199     EX x. x = sel r to True (not enabled by default).
   200   - Tactic "record_split_simp_tac" to split and simplify records added.
   201 
   202 * 'specification' command added, allowing for definition by
   203   specification.  There is also an 'ax_specification' command that
   204   introduces the new constants axiomatically.
   205 
   206 * arith(_tac) is now able to generate counterexamples for reals as well.
   207 
   208 * HOL-Algebra: new locale "ring" for non-commutative rings.
   209 
   210 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   211   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   212 
   213 * HOL-Matrix: a first theory for matrices in HOL with an application of
   214   matrix theory to linear programming.
   215 
   216 * Unions and Intersections:
   217   The x-symbol output syntax of UN and INT has been changed
   218   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   219   i.e. the index formulae has become a subscript, like in normal math.
   220   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   221   The subscript version is also accepted as input syntax.
   222 
   223 * Unions and Intersections over Intervals:
   224   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   225   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   226   like in normal math, and corresponding versions for < and for intersection.
   227 
   228 * ML: the legacy theory structures Int and List have been removed. They had
   229   conflicted with ML Basis Library structures having the same names.
   230 
   231 * 'refute' command added to search for (finite) countermodels.  Only works
   232   for a fragment of HOL.  The installation of an external SAT solver is
   233   highly recommended.  See "HOL/Refute.thy" for details.
   234 
   235 * 'quickcheck' command: Allows to find counterexamples by evaluating
   236   formulae under an assignment of free variables to random values.
   237   In contrast to 'refute', it can deal with inductive datatypes,
   238   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   239   for examples.
   240 
   241 
   242 *** HOLCF ***
   243 
   244 * Streams now come with concatenation and are part of the HOLCF image
   245 
   246 
   247 
   248 New in Isabelle2003 (May 2003)
   249 ------------------------------
   250 
   251 *** General ***
   252 
   253 * Provers/simplifier:
   254 
   255   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   256     Assumptions are now subject to complete mutual simplification,
   257     not just from left to right. The simplifier now preserves
   258     the order of assumptions.
   259 
   260     Potential INCOMPATIBILITY:
   261 
   262     -- simp sometimes diverges where the old version did
   263        not, e.g. invoking simp on the goal
   264 
   265         [| P (f x); y = x; f x = f y |] ==> Q
   266 
   267        now gives rise to the infinite reduction sequence
   268 
   269         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   270 
   271        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   272        kind of problem.
   273 
   274     -- Tactics combining classical reasoner and simplification (such as auto)
   275        are also affected by this change, because many of them rely on
   276        simp. They may sometimes diverge as well or yield a different numbers
   277        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   278        in case of problems. Sometimes subsequent calls to the classical
   279        reasoner will fail because a preceeding call to the simplifier too
   280        eagerly simplified the goal, e.g. deleted redundant premises.
   281 
   282   - The simplifier trace now shows the names of the applied rewrite rules
   283 
   284   - You can limit the number of recursive invocations of the simplifier
   285     during conditional rewriting (where the simplifie tries to solve the
   286     conditions before applying the rewrite rule):
   287     ML "simp_depth_limit := n"
   288     where n is an integer. Thus you can force termination where previously
   289     the simplifier would diverge.
   290 
   291   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   292 
   293   - No longer aborts on failed congruence proof.  Instead, the
   294     congruence is ignored.
   295 
   296 * Pure: New generic framework for extracting programs from constructive
   297   proofs. See HOL/Extraction.thy for an example instantiation, as well
   298   as HOL/Extraction for some case studies.
   299 
   300 * Pure: The main goal of the proof state is no longer shown by default, only
   301 the subgoals. This behaviour is controlled by a new flag.
   302    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   303 (ML: Proof.show_main_goal).
   304 
   305 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   306 rules whose conclusion matches subgoal 1:
   307       PG menu: Isabelle/Isar -> Show me -> matching rules
   308 The rules are ordered by how closely they match the subgoal.
   309 In particular, rules that solve a subgoal outright are displayed first
   310 (or rather last, the way they are printed).
   311 (ML: ProofGeneral.print_intros())
   312 
   313 * Pure: New flag trace_unify_fail causes unification to print
   314 diagnostic information (PG: in trace buffer) when it fails. This is
   315 useful for figuring out why single step proofs like rule, erule or
   316 assumption failed.
   317 
   318 * Pure: Locale specifications now produce predicate definitions
   319 according to the body of text (covering assumptions modulo local
   320 definitions); predicate "loc_axioms" covers newly introduced text,
   321 while "loc" is cumulative wrt. all included locale expressions; the
   322 latter view is presented only on export into the global theory
   323 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   324 on the old view without predicates;
   325 
   326 * Pure: predefined locales "var" and "struct" are useful for sharing
   327 parameters (as in CASL, for example); just specify something like
   328 ``var x + var y + struct M'' as import;
   329 
   330 * Pure: improved thms_containing: proper indexing of facts instead of
   331 raw theorems; check validity of results wrt. current name space;
   332 include local facts of proof configuration (also covers active
   333 locales), cover fixed variables in index; may use "_" in term
   334 specification; an optional limit for the number of printed facts may
   335 be given (the default is 40);
   336 
   337 * Pure: disallow duplicate fact bindings within new-style theory files
   338 (batch-mode only);
   339 
   340 * Provers: improved induct method: assumptions introduced by case
   341 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   342 the goal statement); "foo" still refers to all facts collectively;
   343 
   344 * Provers: the function blast.overloaded has been removed: all constants
   345 are regarded as potentially overloaded, which improves robustness in exchange
   346 for slight decrease in efficiency;
   347 
   348 * Provers/linorder: New generic prover for transitivity reasoning over
   349 linear orders.  Note: this prover is not efficient!
   350 
   351 * Isar: preview of problems to finish 'show' now produce an error
   352 rather than just a warning (in interactive mode);
   353 
   354 
   355 *** HOL ***
   356 
   357 * arith(_tac)
   358 
   359  - Produces a counter example if it cannot prove a goal.
   360    Note that the counter example may be spurious if the goal is not a formula
   361    of quantifier-free linear arithmetic.
   362    In ProofGeneral the counter example appears in the trace buffer.
   363 
   364  - Knows about div k and mod k where k is a numeral of type nat or int.
   365 
   366  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   367    linear arithmetic fails. This takes account of quantifiers and divisibility.
   368    Presburger arithmetic can also be called explicitly via presburger(_tac).
   369 
   370 * simp's arithmetic capabilities have been enhanced a bit: it now
   371 takes ~= in premises into account (by performing a case split);
   372 
   373 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   374 are distributed over a sum of terms;
   375 
   376 * New tactic "trans_tac" and method "trans" instantiate
   377 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   378 "<=", "<" and "=").
   379 
   380 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   381 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   382 
   383 * 'typedef' command has new option "open" to suppress the set
   384 definition;
   385 
   386 * functions Min and Max on finite sets have been introduced (theory
   387 Finite_Set);
   388 
   389 * attribute [symmetric] now works for relations as well; it turns
   390 (x,y) : R^-1 into (y,x) : R, and vice versa;
   391 
   392 * induct over a !!-quantified statement (say !!x1..xn):
   393   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   394 
   395 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   396 %x. None. Warning: empty_def now refers to the previously hidden definition
   397 of the empty set.
   398 
   399 * Algebra: formalization of classical algebra.  Intended as base for
   400 any algebraic development in Isabelle.  Currently covers group theory
   401 (up to Sylow's theorem) and ring theory (Universal Property of
   402 Univariate Polynomials).  Contributions welcome;
   403 
   404 * GroupTheory: deleted, since its material has been moved to Algebra;
   405 
   406 * Complex: new directory of the complex numbers with numeric constants,
   407 nonstandard complex numbers, and some complex analysis, standard and
   408 nonstandard (Jacques Fleuriot);
   409 
   410 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   411 
   412 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   413 Fleuriot);
   414 
   415 * Real/HahnBanach: updated and adapted to locales;
   416 
   417 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   418 Gray and Kramer);
   419 
   420 * UNITY: added the Meier-Sanders theory of progress sets;
   421 
   422 * MicroJava: bytecode verifier and lightweight bytecode verifier
   423 as abstract algorithms, instantiated to the JVM;
   424 
   425 * Bali: Java source language formalization. Type system, operational
   426 semantics, axiomatic semantics. Supported language features:
   427 classes, interfaces, objects,virtual methods, static methods,
   428 static/instance fields, arrays, access modifiers, definite
   429 assignment, exceptions.
   430 
   431 
   432 *** ZF ***
   433 
   434 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   435 universe, etc.);
   436 
   437 * Main ZF: virtually all theories converted to new-style format;
   438 
   439 
   440 *** ML ***
   441 
   442 * Pure: Tactic.prove provides sane interface for internal proofs;
   443 omits the infamous "standard" operation, so this is more appropriate
   444 than prove_goalw_cterm in many situations (e.g. in simprocs);
   445 
   446 * Pure: improved error reporting of simprocs;
   447 
   448 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   449 up simprocs;
   450 
   451 
   452 *** Document preparation ***
   453 
   454 * uses \par instead of \\ for line breaks in theory text. This may
   455 shift some page breaks in large documents. To get the old behaviour
   456 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   457 
   458 * minimized dependencies of isabelle.sty and isabellesym.sty on
   459 other packages
   460 
   461 * \<euro> now needs package babel/greek instead of marvosym (which
   462 broke \Rightarrow)
   463 
   464 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   465 textcomp package)
   466 
   467 
   468 
   469 New in Isabelle2002 (March 2002)
   470 --------------------------------
   471 
   472 *** Document preparation ***
   473 
   474 * greatly simplified document preparation setup, including more
   475 graceful interpretation of isatool usedir -i/-d/-D options, and more
   476 instructive isatool mkdir; users should basically be able to get
   477 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   478 users may run a separate document processing stage manually like this:
   479 "isatool usedir -D output HOL Test && isatool document Test/output";
   480 
   481 * theory dependency graph may now be incorporated into documents;
   482 isatool usedir -g true will produce session_graph.eps/.pdf for use
   483 with \includegraphics of LaTeX;
   484 
   485 * proper spacing of consecutive markup elements, especially text
   486 blocks after section headings;
   487 
   488 * support bold style (for single symbols only), input syntax is like
   489 this: "\<^bold>\<alpha>" or "\<^bold>A";
   490 
   491 * \<bullet> is now output as bold \cdot by default, which looks much
   492 better in printed text;
   493 
   494 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   495 note that these symbols are currently unavailable in Proof General /
   496 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   497 
   498 * isatool latex no longer depends on changed TEXINPUTS, instead
   499 isatool document copies the Isabelle style files to the target
   500 location;
   501 
   502 
   503 *** Isar ***
   504 
   505 * Pure/Provers: improved proof by cases and induction;
   506   - 'case' command admits impromptu naming of parameters (such as
   507     "case (Suc n)");
   508   - 'induct' method divinates rule instantiation from the inductive
   509     claim; no longer requires excessive ?P bindings for proper
   510     instantiation of cases;
   511   - 'induct' method properly enumerates all possibilities of set/type
   512     rules; as a consequence facts may be also passed through *type*
   513     rules without further ado;
   514   - 'induct' method now derives symbolic cases from the *rulified*
   515     rule (before it used to rulify cases stemming from the internal
   516     atomized version); this means that the context of a non-atomic
   517     statement becomes is included in the hypothesis, avoiding the
   518     slightly cumbersome show "PROP ?case" form;
   519   - 'induct' may now use elim-style induction rules without chaining
   520     facts, using ``missing'' premises from the goal state; this allows
   521     rules stemming from inductive sets to be applied in unstructured
   522     scripts, while still benefitting from proper handling of non-atomic
   523     statements; NB: major inductive premises need to be put first, all
   524     the rest of the goal is passed through the induction;
   525   - 'induct' proper support for mutual induction involving non-atomic
   526     rule statements (uses the new concept of simultaneous goals, see
   527     below);
   528   - append all possible rule selections, but only use the first
   529     success (no backtracking);
   530   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   531   - undeclared rule case names default to numbers 1, 2, 3, ...;
   532   - added 'print_induct_rules' (covered by help item in recent Proof
   533     General versions);
   534   - moved induct/cases attributes to Pure, methods to Provers;
   535   - generic method setup instantiated for FOL and HOL;
   536 
   537 * Pure: support multiple simultaneous goal statements, for example
   538 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   539 meta-level mechanism, this acts as if several individual goals had
   540 been stated separately; in particular common proof methods need to be
   541 repeated in order to cover all claims; note that a single elimination
   542 step is *not* sufficient to establish the two conjunctions, so this
   543 fails:
   544 
   545   assume "A & B" then have A and B ..   (*".." fails*)
   546 
   547 better use "obtain" in situations as above; alternative refer to
   548 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   549 
   550 * Pure: proper integration with ``locales''; unlike the original
   551 version by Florian Kammüller, Isar locales package high-level proof
   552 contexts rather than raw logical ones (e.g. we admit to include
   553 attributes everywhere); operations on locales include merge and
   554 rename; support for implicit arguments (``structures''); simultaneous
   555 type-inference over imports and text; see also HOL/ex/Locales.thy for
   556 some examples;
   557 
   558 * Pure: the following commands have been ``localized'', supporting a
   559 target locale specification "(in name)": 'lemma', 'theorem',
   560 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   561 stored both within the locale and at the theory level (exported and
   562 qualified by the locale name);
   563 
   564 * Pure: theory goals may now be specified in ``long'' form, with
   565 ad-hoc contexts consisting of arbitrary locale elements. for example
   566 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   567 definitions may be given, too); the result is a meta-level rule with
   568 the context elements being discharged in the obvious way;
   569 
   570 * Pure: new proof command 'using' allows to augment currently used
   571 facts after a goal statement ('using' is syntactically analogous to
   572 'apply', but acts on the goal's facts only); this allows chained facts
   573 to be separated into parts given before and after a claim, as in
   574 ``from a and b have C using d and e <proof>'';
   575 
   576 * Pure: renamed "antecedent" case to "rule_context";
   577 
   578 * Pure: new 'judgment' command records explicit information about the
   579 object-logic embedding (used by several tools internally); no longer
   580 use hard-wired "Trueprop";
   581 
   582 * Pure: added 'corollary' command;
   583 
   584 * Pure: fixed 'token_translation' command;
   585 
   586 * Pure: removed obsolete 'exported' attribute;
   587 
   588 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   589 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   590 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   591 
   592 * Pure: method 'atomize' presents local goal premises as object-level
   593 statements (atomic meta-level propositions); setup controlled via
   594 rewrite rules declarations of 'atomize' attribute; example
   595 application: 'induct' method with proper rule statements in improper
   596 proof *scripts*;
   597 
   598 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   599 now consider the syntactic context of assumptions, giving a better
   600 chance to get type-inference of the arguments right (this is
   601 especially important for locales);
   602 
   603 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   604 mode;
   605 
   606 * Pure/obtain: the formal conclusion "thesis", being marked as
   607 ``internal'', may no longer be reference directly in the text;
   608 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   609 situations;
   610 
   611 * Pure: generic 'sym' attribute which declares a rule both as pure
   612 'elim?' and for the 'symmetric' operation;
   613 
   614 * Pure: marginal comments ``--'' may now occur just anywhere in the
   615 text; the fixed correlation with particular command syntax has been
   616 discontinued;
   617 
   618 * Pure: new method 'rules' is particularly well-suited for proof
   619 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   620 but often produces more compact proof terms with less detours;
   621 
   622 * Pure/Provers/classical: simplified integration with pure rule
   623 attributes and methods; the classical "intro?/elim?/dest?"
   624 declarations coincide with the pure ones; the "rule" method no longer
   625 includes classically swapped intros; "intro" and "elim" methods no
   626 longer pick rules from the context; also got rid of ML declarations
   627 AddXIs/AddXEs/AddXDs; all of this has some potential for
   628 INCOMPATIBILITY;
   629 
   630 * Provers/classical: attribute 'swapped' produces classical inversions
   631 of introduction rules;
   632 
   633 * Provers/simplifier: 'simplified' attribute may refer to explicit
   634 rules instead of full simplifier context; 'iff' attribute handles
   635 conditional rules;
   636 
   637 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   638 
   639 * HOL: 'recdef' now fails on unfinished automated proofs, use
   640 "(permissive)" option to recover old behavior;
   641 
   642 * HOL: 'inductive' no longer features separate (collective) attributes
   643 for 'intros' (was found too confusing);
   644 
   645 * HOL: properly declared induction rules less_induct and
   646 wf_induct_rule;
   647 
   648 
   649 *** HOL ***
   650 
   651 * HOL: moved over to sane numeral syntax; the new policy is as
   652 follows:
   653 
   654   - 0 and 1 are polymorphic constants, which are defined on any
   655   numeric type (nat, int, real etc.);
   656 
   657   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   658   binary representation internally;
   659 
   660   - type nat has special constructor Suc, and generally prefers Suc 0
   661   over 1::nat and Suc (Suc 0) over 2::nat;
   662 
   663 This change may cause significant problems of INCOMPATIBILITY; here
   664 are some hints on converting existing sources:
   665 
   666   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   667   entities, so expressions involving "-" (unary or binary minus) need
   668   to be spaced properly;
   669 
   670   - existing occurrences of "1" may need to be constraint "1::nat" or
   671   even replaced by Suc 0; similar for old "2";
   672 
   673   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   674 
   675   - remove all special provisions on numerals in proofs;
   676 
   677 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   678 representation (depends on bin_arith_simps in the default context);
   679 
   680 * HOL: symbolic syntax for x^2 (numeral 2);
   681 
   682 * HOL: the class of all HOL types is now called "type" rather than
   683 "term"; INCOMPATIBILITY, need to adapt references to this type class
   684 in axclass/classes, instance/arities, and (usually rare) occurrences
   685 in typings (of consts etc.); internally the class is called
   686 "HOL.type", ML programs should refer to HOLogic.typeS;
   687 
   688 * HOL/record package improvements:
   689   - new derived operations "fields" to build a partial record section,
   690     "extend" to promote a fixed record to a record scheme, and
   691     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   692     declared as simp by default;
   693   - shared operations ("more", "fields", etc.) now need to be always
   694     qualified) --- potential INCOMPATIBILITY;
   695   - removed "make_scheme" operations (use "make" with "extend") --
   696     INCOMPATIBILITY;
   697   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   698   - provides cases/induct rules for use with corresponding Isar
   699     methods (for concrete records, record schemes, concrete more
   700     parts, and schematic more parts -- in that order);
   701   - internal definitions directly based on a light-weight abstract
   702     theory of product types over typedef rather than datatype;
   703 
   704 * HOL: generic code generator for generating executable ML code from
   705 specifications; specific support for HOL constructs such as inductive
   706 datatypes and sets, as well as recursive functions; can be invoked
   707 via 'generate_code' theory section;
   708 
   709 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   710 
   711 * HOL: consolidated and renamed several theories.  In particular:
   712         Ord.thy has been absorbed into HOL.thy
   713         String.thy has been absorbed into List.thy
   714 
   715 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   716 (beware of argument permutation!);
   717 
   718 * HOL: linorder_less_split superseded by linorder_cases;
   719 
   720 * HOL/List: "nodups" renamed to "distinct";
   721 
   722 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   723 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   724   - Ex_def has changed, now need to use some_eq_ex
   725 
   726 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   727 in this (rare) case use:
   728 
   729   delSWrapper "split_all_tac"
   730   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   731 
   732 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   733 MAY FAIL;
   734 
   735 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   736 Isabelle's type classes, ^ on functions and relations has too general
   737 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   738 necessary to attach explicit type constraints;
   739 
   740 * HOL/Relation: the prefix name of the infix "O" has been changed from
   741 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   742 renamed accordingly (eg "compI" -> "rel_compI").
   743 
   744 * HOL: syntax translations now work properly with numerals and records
   745 expressions;
   746 
   747 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   748 of "lam" -- INCOMPATIBILITY;
   749 
   750 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   751 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   752 renamed "Product_Type.unit";
   753 
   754 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   755 
   756 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   757 the "cases" method);
   758 
   759 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   760 Florian Kammüller);
   761 
   762 * HOL/IMP: updated and converted to new-style theory format; several
   763 parts turned into readable document, with proper Isar proof texts and
   764 some explanations (by Gerwin Klein);
   765 
   766 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   767 
   768 * HOL-Hyperreal is now a logic image;
   769 
   770 
   771 *** HOLCF ***
   772 
   773 * Isar: consts/constdefs supports mixfix syntax for continuous
   774 operations;
   775 
   776 * Isar: domain package adapted to new-style theory format, e.g. see
   777 HOLCF/ex/Dnat.thy;
   778 
   779 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   780 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   781 lift.induct_tac, always use UU instead of Undef;
   782 
   783 * HOLCF/IMP: updated and converted to new-style theory;
   784 
   785 
   786 *** ZF ***
   787 
   788 * Isar: proper integration of logic-specific tools and packages,
   789 including theory commands '(co)inductive', '(co)datatype',
   790 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   791 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   792 
   793 * theory Main no longer includes AC; for the Axiom of Choice, base
   794 your theory on Main_ZFC;
   795 
   796 * the integer library now covers quotients and remainders, with many
   797 laws relating division to addition, multiplication, etc.;
   798 
   799 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   800 typeless version of the formalism;
   801 
   802 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   803 format;
   804 
   805 * ZF/Induct: new directory for examples of inductive definitions,
   806 including theory Multiset for multiset orderings; converted to
   807 new-style theory format;
   808 
   809 * ZF: many new theorems about lists, ordinals, etc.;
   810 
   811 
   812 *** General ***
   813 
   814 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   815 variable proof controls level of detail: 0 = no proofs (only oracle
   816 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   817 also ref manual for further ML interfaces;
   818 
   819 * Pure/axclass: removed obsolete ML interface
   820 goal_subclass/goal_arity;
   821 
   822 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   823 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   824 separate tokens, so expressions involving minus need to be spaced
   825 properly;
   826 
   827 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   828 rather than "infixl" or "infixr";
   829 
   830 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   831 sort constraint specifications in type inference; e.g. "x::_::foo"
   832 ensures that the type of "x" is of sort "foo" (but not necessarily a
   833 type variable);
   834 
   835 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   836 control output of nested => (types); the default behavior is
   837 "type_brackets";
   838 
   839 * Pure/syntax: builtin parse translation for "_constify" turns valued
   840 tokens into AST constants;
   841 
   842 * Pure/syntax: prefer later declarations of translations and print
   843 translation functions; potential INCOMPATIBILITY: need to reverse
   844 multiple declarations for same syntax element constant;
   845 
   846 * Pure/show_hyps reset by default (in accordance to existing Isar
   847 practice);
   848 
   849 * Provers/classical: renamed addaltern to addafter, addSaltern to
   850 addSafter;
   851 
   852 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   853 as well;
   854 
   855 * system: tested support for MacOS X; should be able to get Isabelle +
   856 Proof General to work in a plain Terminal after installing Poly/ML
   857 (e.g. from the Isabelle distribution area) and GNU bash alone
   858 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   859 support requires further installations, e.g. from
   860 http://fink.sourceforge.net/);
   861 
   862 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   863 
   864 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   865 of 40 MB), cf. ML_OPTIONS;
   866 
   867 * system: Proof General keywords specification is now part of the
   868 Isabelle distribution (see etc/isar-keywords.el);
   869 
   870 * system: support for persistent Proof General sessions (refrain from
   871 outdating all loaded theories on startup); user may create writable
   872 logic images like this: ``isabelle -q HOL Test'';
   873 
   874 * system: smart selection of Isabelle process versus Isabelle
   875 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   876 run both "isabelle" and "Isabelle" even if file names are badly
   877 damaged (executable inspects the case of the first letter of its own
   878 name); added separate "isabelle-process" and "isabelle-interface";
   879 
   880 * system: refrain from any attempt at filtering input streams; no
   881 longer support ``8bit'' encoding of old isabelle font, instead proper
   882 iso-latin characters may now be used; the related isatools
   883 "symbolinput" and "nonascii" have disappeared as well;
   884 
   885 * system: removed old "xterm" interface (the print modes "xterm" and
   886 "xterm_color" are still available for direct use in a suitable
   887 terminal);
   888 
   889 
   890 
   891 New in Isabelle99-2 (February 2001)
   892 -----------------------------------
   893 
   894 *** Overview of INCOMPATIBILITIES ***
   895 
   896 * HOL: please note that theories in the Library and elsewhere often use the
   897 new-style (Isar) format; to refer to their theorems in an ML script you must
   898 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   899 
   900 * HOL: inductive package no longer splits induction rule aggressively,
   901 but only as far as specified by the introductions given; the old
   902 format may be recovered via ML function complete_split_rule or attribute
   903 'split_rule (complete)';
   904 
   905 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   906 gfp_Tarski to gfp_unfold;
   907 
   908 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   909 
   910 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   911 relation); infix "^^" has been renamed "``"; infix "``" has been
   912 renamed "`"; "univalent" has been renamed "single_valued";
   913 
   914 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   915 operation;
   916 
   917 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   918 
   919 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   920 
   921 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   922 consequence, it is no longer monotonic wrt. the local goal context
   923 (which is now passed through the inductive cases);
   924 
   925 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   926 \<gg> to \<ggreater>;
   927 
   928 
   929 *** Document preparation ***
   930 
   931 * \isabellestyle{NAME} selects version of Isabelle output (currently
   932 available: are "it" for near math-mode best-style output, "sl" for
   933 slanted text style, and "tt" for plain type-writer; if no
   934 \isabellestyle command is given, output is according to slanted
   935 type-writer);
   936 
   937 * support sub/super scripts (for single symbols only), input syntax is
   938 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   939 
   940 * some more standard symbols; see Appendix A of the system manual for
   941 the complete list of symbols defined in isabellesym.sty;
   942 
   943 * improved isabelle style files; more abstract symbol implementation
   944 (should now use \isamath{...} and \isatext{...} in custom symbol
   945 definitions);
   946 
   947 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   948 state; Note that presentation of goal states does not conform to
   949 actual human-readable proof documents.  Please do not include goal
   950 states into document output unless you really know what you are doing!
   951 
   952 * proper indentation of antiquoted output with proportional LaTeX
   953 fonts;
   954 
   955 * no_document ML operator temporarily disables LaTeX document
   956 generation;
   957 
   958 * isatool unsymbolize tunes sources for plain ASCII communication;
   959 
   960 
   961 *** Isar ***
   962 
   963 * Pure: Isar now suffers initial goal statements to contain unbound
   964 schematic variables (this does not conform to actual readable proof
   965 documents, due to unpredictable outcome and non-compositional proof
   966 checking); users who know what they are doing may use schematic goals
   967 for Prolog-style synthesis of proven results;
   968 
   969 * Pure: assumption method (an implicit finishing) now handles actual
   970 rules as well;
   971 
   972 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   973 initial goal, declare "that" only as Pure intro (only for single
   974 steps); the "that" rule assumption may now be involved in implicit
   975 finishing, thus ".." becomes a feasible for trivial obtains;
   976 
   977 * Pure: default proof step now includes 'intro_classes'; thus trivial
   978 instance proofs may be performed by "..";
   979 
   980 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   981 statements as well;
   982 
   983 * Pure: more robust selection of calculational rules;
   984 
   985 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   986 rule (as well as the assumption rule);
   987 
   988 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   989 lemmas, using the graph browser tool;
   990 
   991 * Pure: predict failure of "show" in interactive mode;
   992 
   993 * Pure: 'thms_containing' now takes actual terms as arguments;
   994 
   995 * HOL: improved method 'induct' --- now handles non-atomic goals
   996 (potential INCOMPATIBILITY); tuned error handling;
   997 
   998 * HOL: cases and induct rules now provide explicit hints about the
   999 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1000 any remaining facts are inserted into the goal verbatim;
  1001 
  1002 * HOL: local contexts (aka cases) may now contain term bindings as
  1003 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1004 the result to be shown in each case;
  1005 
  1006 * HOL: added 'recdef_tc' command;
  1007 
  1008 * isatool convert assists in eliminating legacy ML scripts;
  1009 
  1010 
  1011 *** HOL ***
  1012 
  1013 * HOL/Library: a collection of generic theories to be used together
  1014 with main HOL; the theory loader path already includes this directory
  1015 by default; the following existing theories have been moved here:
  1016 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1017 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1018 
  1019 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1020 modelling and verification task performed in Isabelle/HOL +
  1021 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1022 
  1023 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1024 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1025 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1026 'domain', this makes the theory consistent with mathematical
  1027 literature;
  1028 
  1029 * HOL basics: added overloaded operations "inverse" and "divide"
  1030 (infix "/"), syntax for generic "abs" operation, generic summation
  1031 operator \<Sum>;
  1032 
  1033 * HOL/typedef: simplified package, provide more useful rules (see also
  1034 HOL/subset.thy);
  1035 
  1036 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1037 now expressed as a proper nested rule (old-style tactic scripts may
  1038 require atomize_strip_tac to cope with non-atomic premises);
  1039 
  1040 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1041 to "split_conv" (old name still available for compatibility);
  1042 
  1043 * HOL: improved concrete syntax for strings (e.g. allows translation
  1044 rules with string literals);
  1045 
  1046 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1047  and Fleuriot's mechanization of analysis, including the transcendental
  1048  functions for the reals;
  1049 
  1050 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1051 
  1052 
  1053 *** CTT ***
  1054 
  1055 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1056 "lam" is displayed as TWO lambda-symbols
  1057 
  1058 * CTT: theory Main now available, containing everything (that is, Bool
  1059 and Arith);
  1060 
  1061 
  1062 *** General ***
  1063 
  1064 * Pure: the Simplifier has been implemented properly as a derived rule
  1065 outside of the actual kernel (at last!); the overall performance
  1066 penalty in practical applications is about 50%, while reliability of
  1067 the Isabelle inference kernel has been greatly improved;
  1068 
  1069 * print modes "brackets" and "no_brackets" control output of nested =>
  1070 (types) and ==> (props); the default behaviour is "brackets";
  1071 
  1072 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1073 as assumptions as well;
  1074 
  1075 * system: support Poly/ML 4.0;
  1076 
  1077 * system: isatool install handles KDE version 1 or 2;
  1078 
  1079 
  1080 
  1081 New in Isabelle99-1 (October 2000)
  1082 ----------------------------------
  1083 
  1084 *** Overview of INCOMPATIBILITIES ***
  1085 
  1086 * HOL: simplification of natural numbers is much changed; to partly
  1087 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1088 issue the following ML commands:
  1089 
  1090   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1091   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1092 
  1093 * HOL: simplification no longer dives into case-expressions; this is
  1094 controlled by "t.weak_case_cong" for each datatype t;
  1095 
  1096 * HOL: nat_less_induct renamed to less_induct;
  1097 
  1098 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1099 fixsome to patch .thy and .ML sources automatically;
  1100 
  1101   select_equality  -> some_equality
  1102   select_eq_Ex     -> some_eq_ex
  1103   selectI2EX       -> someI2_ex
  1104   selectI2         -> someI2
  1105   selectI          -> someI
  1106   select1_equality -> some1_equality
  1107   Eps_sym_eq       -> some_sym_eq_trivial
  1108   Eps_eq           -> some_eq_trivial
  1109 
  1110 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1111 
  1112 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1113 instead);
  1114 
  1115 * HOL: the recursion equations generated by 'recdef' are now called
  1116 f.simps instead of f.rules;
  1117 
  1118 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1119 
  1120 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1121 sometimes be needed;
  1122 
  1123 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1124 
  1125 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1126 
  1127 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1128 product is now "<*>" instead of "Times"; the lexicographic product is
  1129 now "<*lex*>" instead of "**";
  1130 
  1131 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1132 of main HOL, but was unused); better use HOL's datatype package;
  1133 
  1134 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1135 the old syntax may be recovered as follows:
  1136 
  1137   syntax (symbols)
  1138     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1139       (infixl "\\<oplus>" 100)
  1140 
  1141 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1142 
  1143 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1144 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1145 internally;
  1146 
  1147 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1148 changed from A/r to A//r;
  1149 
  1150 * ZF: new treatment of arithmetic (nat & int) may break some old
  1151 proofs;
  1152 
  1153 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1154 rulify -> rule_format, elimify -> elim_format, ...);
  1155 
  1156 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1157 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1158 should have to change intro!! to intro? only); replaced "delrule" by
  1159 "rule del";
  1160 
  1161 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1162 
  1163 * Provers: strengthened force_tac by using new first_best_tac;
  1164 
  1165 * LaTeX document preparation: several changes of isabelle.sty (see
  1166 lib/texinputs);
  1167 
  1168 
  1169 *** Document preparation ***
  1170 
  1171 * formal comments (text blocks etc.) in new-style theories may now
  1172 contain antiquotations of thm/prop/term/typ/text to be presented
  1173 according to latex print mode; concrete syntax is like this:
  1174 @{term[show_types] "f(x) = a + x"};
  1175 
  1176 * isatool mkdir provides easy setup of Isabelle session directories,
  1177 including proper document sources;
  1178 
  1179 * generated LaTeX sources are now deleted after successful run
  1180 (isatool document -c); may retain a copy somewhere else via -D option
  1181 of isatool usedir;
  1182 
  1183 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1184 style files, achieving self-contained LaTeX sources and simplifying
  1185 LaTeX debugging;
  1186 
  1187 * old-style theories now produce (crude) LaTeX output as well;
  1188 
  1189 * browser info session directories are now self-contained (may be put
  1190 on WWW server seperately); improved graphs of nested sessions; removed
  1191 graph for 'all sessions';
  1192 
  1193 * several improvements in isabelle style files; \isabellestyle{it}
  1194 produces fake math mode output; \isamarkupheader is now \section by
  1195 default; see lib/texinputs/isabelle.sty etc.;
  1196 
  1197 
  1198 *** Isar ***
  1199 
  1200 * Isar/Pure: local results and corresponding term bindings are now
  1201 subject to Hindley-Milner polymorphism (similar to ML); this
  1202 accommodates incremental type-inference very nicely;
  1203 
  1204 * Isar/Pure: new derived language element 'obtain' supports
  1205 generalized existence reasoning;
  1206 
  1207 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1208 support accumulation of results, without applying any rules yet;
  1209 useful to collect intermediate results without explicit name
  1210 references, and for use with transitivity rules with more than 2
  1211 premises;
  1212 
  1213 * Isar/Pure: scalable support for case-analysis type proofs: new
  1214 'case' language element refers to local contexts symbolically, as
  1215 produced by certain proof methods; internally, case names are attached
  1216 to theorems as "tags";
  1217 
  1218 * Isar/Pure: theory command 'hide' removes declarations from
  1219 class/type/const name spaces;
  1220 
  1221 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1222 indicate potential overloading;
  1223 
  1224 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1225 
  1226 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1227 "{a,b,c}" instead of {a,b,c};
  1228 
  1229 * Isar/Pure now provides its own version of intro/elim/dest
  1230 attributes; useful for building new logics, but beware of confusion
  1231 with the version in Provers/classical;
  1232 
  1233 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1234 case name 'antecedent';
  1235 
  1236 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1237 to the current context is now done automatically);
  1238 
  1239 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1240 for definining proof methods in ML;
  1241 
  1242 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1243 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1244 most cases, one should have to change intro!! to intro? only);
  1245 replaced "delrule" by "rule del";
  1246 
  1247 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1248 'symmetric' attribute (the latter supercedes [RS sym]);
  1249 
  1250 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1251 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1252 well (including splits);
  1253 
  1254 * Isar/Provers: Simplifier and Classical methods now support all kind
  1255 of modifiers used in the past, including 'cong', 'iff', etc.
  1256 
  1257 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1258 of Simplifier and Classical reasoner);
  1259 
  1260 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1261 now support named cases; major packages (inductive, datatype, primrec,
  1262 recdef) support case names and properly name parameters;
  1263 
  1264 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1265 monotonicity conditions are extracted to be proven at end of
  1266 calculations;
  1267 
  1268 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1269 method anyway;
  1270 
  1271 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1272 split_if split_if_asm; datatype package provides theorems foo.splits =
  1273 foo.split foo.split_asm for each datatype;
  1274 
  1275 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1276 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1277 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1278 use "(cases (simplified))" method in proper proof texts);
  1279 
  1280 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1281 
  1282 * Isar: names of theorems etc. may be natural numbers as well;
  1283 
  1284 * Isar: 'pr' command: optional arguments for goals_limit and
  1285 ProofContext.prems_limit; no longer prints theory contexts, but only
  1286 proof states;
  1287 
  1288 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1289 additional print modes to be specified; e.g. "pr(latex)" will print
  1290 proof state according to the Isabelle LaTeX style;
  1291 
  1292 * Isar: improved support for emulating tactic scripts, including proof
  1293 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1294 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1295 (for HOL datatypes);
  1296 
  1297 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1298 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1299 'proof method scripts' have to be in depth-first order;
  1300 
  1301 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1302 
  1303 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1304 should instead use individual commands for printing items
  1305 (print_commands, print_methods etc.);
  1306 
  1307 * Isar: added 'nothing' --- the empty list of theorems;
  1308 
  1309 
  1310 *** HOL ***
  1311 
  1312 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1313 corresponding virtual machine and a specification of its bytecode
  1314 verifier and a lightweight bytecode verifier, including proofs of
  1315 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1316 Cornelia Pusch (see also the homepage of project Bali at
  1317 http://isabelle.in.tum.de/Bali/);
  1318 
  1319 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1320 Clemens Ballarin;
  1321 
  1322 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1323 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1324 Rasmussen;
  1325 
  1326 * HOL/Lattice: fundamental concepts of lattice theory and order
  1327 structures, including duals, properties of bounds versus algebraic
  1328 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1329 Theorem for complete lattices etc.; may also serve as a demonstration
  1330 for abstract algebraic reasoning using axiomatic type classes, and
  1331 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1332 
  1333 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1334 von Oheimb;
  1335 
  1336 * HOL/IMPP: extension of IMP with local variables and mutually
  1337 recursive procedures, by David von Oheimb;
  1338 
  1339 * HOL/Lambda: converted into new-style theory and document;
  1340 
  1341 * HOL/ex/Multiquote: example of multiple nested quotations and
  1342 anti-quotations -- basically a generalized version of de-Bruijn
  1343 representation; very useful in avoiding lifting of operations;
  1344 
  1345 * HOL/record: added general record equality rule to simpset; fixed
  1346 select-update simplification procedure to handle extended records as
  1347 well; admit "r" as field name;
  1348 
  1349 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1350 other numeric types and also as the identity of groups, rings, etc.;
  1351 
  1352 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1353 Types nat and int belong to this axclass;
  1354 
  1355 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1356    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1357    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1358   two terms #m*u and #n*u are replaced by #(m+n)*u
  1359     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1360   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1361     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1362 
  1363 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1364 powerful prover for predicate logic but knows nothing of clasets; see
  1365 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1366 
  1367 * HOL: new version of "case_tac" subsumes both boolean case split and
  1368 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1369 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1370 
  1371 * HOL: simplification no longer dives into case-expressions: only the
  1372 selector expression is simplified, but not the remaining arms; to
  1373 enable full simplification of case-expressions for datatype t, you may
  1374 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1375 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1376 
  1377 * HOL/recdef: the recursion equations generated by 'recdef' for
  1378 function 'f' are now called f.simps instead of f.rules; if all
  1379 termination conditions are proved automatically, these simplification
  1380 rules are added to the simpset, as in primrec; rules may be named
  1381 individually as well, resulting in a separate list of theorems for
  1382 each equation;
  1383 
  1384 * HOL/While is a new theory that provides a while-combinator. It
  1385 permits the definition of tail-recursive functions without the
  1386 provision of a termination measure. The latter is necessary once the
  1387 invariant proof rule for while is applied.
  1388 
  1389 * HOL: new (overloaded) notation for the set of elements below/above
  1390 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1391 
  1392 * HOL: theorems impI, allI, ballI bound as "strip";
  1393 
  1394 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1395 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1396 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1397 
  1398 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1399 
  1400 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1401 main HOL, but was unused);
  1402 
  1403 * HOL: fewer consts declared as global (e.g. have to refer to
  1404 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1405 
  1406 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1407 in case of overlap with user translations (e.g. judgements over
  1408 tuples); (note that the underlying logical represenation is still
  1409 bogus);
  1410 
  1411 
  1412 *** ZF ***
  1413 
  1414 * ZF: simplification automatically cancels common terms in arithmetic
  1415 expressions over nat and int;
  1416 
  1417 * ZF: new treatment of nat to minimize type-checking: all operators
  1418 coerce their operands to a natural number using the function natify,
  1419 making the algebraic laws unconditional;
  1420 
  1421 * ZF: as above, for int: operators coerce their operands to an integer
  1422 using the function intify;
  1423 
  1424 * ZF: the integer library now contains many of the usual laws for the
  1425 orderings, including $<=, and monotonicity laws for $+ and $*;
  1426 
  1427 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1428 simplification;
  1429 
  1430 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1431 to the simplifier and classical reasoner simultaneously;
  1432 
  1433 
  1434 *** General ***
  1435 
  1436 * Provers: blast_tac now handles actual object-logic rules as
  1437 assumptions; note that auto_tac uses blast_tac internally as well;
  1438 
  1439 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1440 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1441 
  1442 * Provers: delrules now handles destruct rules as well (no longer need
  1443 explicit make_elim);
  1444 
  1445 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1446   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1447 use instead the strong form,
  1448   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1449 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1450 from destruct-rules;
  1451 
  1452 * Provers: Simplifier.easy_setup provides a fast path to basic
  1453 Simplifier setup for new object-logics;
  1454 
  1455 * Pure: AST translation rules no longer require constant head on LHS;
  1456 
  1457 * Pure: improved name spaces: ambiguous output is qualified; support
  1458 for hiding of names;
  1459 
  1460 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1461 XSYMBOL_HOME; no longer need to do manual configuration in most
  1462 situations;
  1463 
  1464 * system: compression of ML heaps images may now be controlled via -c
  1465 option of isabelle and isatool usedir (currently only observed by
  1466 Poly/ML);
  1467 
  1468 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1469 useful for remote X11);
  1470 
  1471 * system: provide TAGS file for Isabelle sources;
  1472 
  1473 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1474 order;
  1475 
  1476 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1477 timing flag supersedes proof_timing and Toplevel.trace;
  1478 
  1479 * ML: new combinators |>> and |>>> for incremental transformations
  1480 with secondary results (e.g. certain theory extensions):
  1481 
  1482 * ML: PureThy.add_defs gets additional argument to indicate potential
  1483 overloading (usually false);
  1484 
  1485 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1486 results;
  1487 
  1488 
  1489 
  1490 New in Isabelle99 (October 1999)
  1491 --------------------------------
  1492 
  1493 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1494 
  1495 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1496 are no longer simplified.  (This allows the simplifier to unfold recursive
  1497 functional programs.)  To restore the old behaviour, declare
  1498 
  1499     Delcongs [if_weak_cong];
  1500 
  1501 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1502 complement;
  1503 
  1504 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1505 
  1506 * HOL/datatype: mutual_induct_tac no longer exists --
  1507   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1508 
  1509 * HOL/typedef: fixed type inference for representing set; type
  1510 arguments now have to occur explicitly on the rhs as type constraints;
  1511 
  1512 * ZF: The con_defs part of an inductive definition may no longer refer
  1513 to constants declared in the same theory;
  1514 
  1515 * HOL, ZF: the function mk_cases, generated by the inductive
  1516 definition package, has lost an argument.  To simplify its result, it
  1517 uses the default simpset instead of a supplied list of theorems.
  1518 
  1519 * HOL/List: the constructors of type list are now Nil and Cons;
  1520 
  1521 * Simplifier: the type of the infix ML functions
  1522         setSSolver addSSolver setSolver addSolver
  1523 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1524 for packaging solvers. A solver is created via
  1525         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1526 where the string argument is only a comment.
  1527 
  1528 
  1529 *** Proof tools ***
  1530 
  1531 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1532 decision procedure for linear arithmetic. Currently it is used for
  1533 types `nat', `int', and `real' in HOL (see below); it can, should and
  1534 will be instantiated for other types and logics as well.
  1535 
  1536 * The simplifier now accepts rewrite rules with flexible heads, eg
  1537      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1538   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1539   matching.
  1540 
  1541 
  1542 *** General ***
  1543 
  1544 * New Isabelle/Isar subsystem provides an alternative to traditional
  1545 tactical theorem proving; together with the ProofGeneral/isar user
  1546 interface it offers an interactive environment for developing human
  1547 readable proof documents (Isar == Intelligible semi-automated
  1548 reasoning); for further information see isatool doc isar-ref,
  1549 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1550 
  1551 * improved and simplified presentation of theories: better HTML markup
  1552 (including colors), graph views in several sizes; isatool usedir now
  1553 provides a proper interface for user theories (via -P option); actual
  1554 document preparation based on (PDF)LaTeX is available as well (for
  1555 new-style theories only); see isatool doc system for more information;
  1556 
  1557 * native support for Proof General, both for classic Isabelle and
  1558 Isabelle/Isar;
  1559 
  1560 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1561 using the graph browser tool;
  1562 
  1563 * Isabelle manuals now also available as PDF;
  1564 
  1565 * theory loader rewritten from scratch (may not be fully
  1566 bug-compatible); old loadpath variable has been replaced by show_path,
  1567 add_path, del_path, reset_path functions; new operations such as
  1568 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1569 isatool doc ref);
  1570 
  1571 * improved isatool install: option -k creates KDE application icon,
  1572 option -p DIR installs standalone binaries;
  1573 
  1574 * added ML_PLATFORM setting (useful for cross-platform installations);
  1575 more robust handling of platform specific ML images for SML/NJ;
  1576 
  1577 * the settings environment is now statically scoped, i.e. it is never
  1578 created again in sub-processes invoked from isabelle, isatool, or
  1579 Isabelle;
  1580 
  1581 * path element specification '~~' refers to '$ISABELLE_HOME';
  1582 
  1583 * in locales, the "assumes" and "defines" parts may be omitted if
  1584 empty;
  1585 
  1586 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1587 long arrows);
  1588 
  1589 * new print_mode "HTML";
  1590 
  1591 * new flag show_tags controls display of tags of theorems (which are
  1592 basically just comments that may be attached by some tools);
  1593 
  1594 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1595 mode and goal output format:
  1596 
  1597 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1598 244c244
  1599 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1600 ---
  1601 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1602 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1603 181c181
  1604 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1605 ---
  1606 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1607 
  1608 * function bind_thms stores lists of theorems (cf. bind_thm);
  1609 
  1610 * new shorthand tactics ftac, eatac, datac, fatac;
  1611 
  1612 * qed (and friends) now accept "" as result name; in that case the
  1613 theorem is not stored, but proper checks and presentation of the
  1614 result still apply;
  1615 
  1616 * theorem database now also indexes constants "Trueprop", "all",
  1617 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1618 
  1619 
  1620 *** HOL ***
  1621 
  1622 ** HOL arithmetic **
  1623 
  1624 * There are now decision procedures for linear arithmetic over nat and
  1625 int:
  1626 
  1627 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1628 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1629 are treated as atomic; subformulae not involving type `nat' or `int'
  1630 are ignored; quantified subformulae are ignored unless they are
  1631 positive universal or negative existential. The tactic has to be
  1632 invoked by hand and can be a little bit slow. In particular, the
  1633 running time is exponential in the number of occurrences of `min' and
  1634 `max', and `-' on `nat'.
  1635 
  1636 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1637 (negated) (in)equalities among the premises and the conclusion into
  1638 account (i.e. no compound formulae) and does not know about `min' and
  1639 `max', and `-' on `nat'. It is fast and is used automatically by the
  1640 simplifier.
  1641 
  1642 NB: At the moment, these decision procedures do not cope with mixed
  1643 nat/int formulae where the two parts interact, such as `m < n ==>
  1644 int(m) < int(n)'.
  1645 
  1646 * HOL/Numeral provides a generic theory of numerals (encoded
  1647 efficiently as bit strings); setup for types nat/int/real is in place;
  1648 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1649 int, existing theories and proof scripts may require a few additional
  1650 type constraints;
  1651 
  1652 * integer division and remainder can now be performed on constant
  1653 arguments;
  1654 
  1655 * many properties of integer multiplication, division and remainder
  1656 are now available;
  1657 
  1658 * An interface to the Stanford Validity Checker (SVC) is available through the
  1659 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1660 are proved automatically.  SVC must be installed separately, and its results
  1661 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1662 invocation of the underlying oracle).  For SVC see
  1663   http://verify.stanford.edu/SVC
  1664 
  1665 * IsaMakefile: the HOL-Real target now builds an actual image;
  1666 
  1667 
  1668 ** HOL misc **
  1669 
  1670 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1671 (in Isabelle/Isar) -- by Gertrud Bauer;
  1672 
  1673 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1674 analysis for assembly languages with subtypes;
  1675 
  1676 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1677 -- avoids syntactic ambiguities and treats state, transition, and
  1678 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1679 changed syntax and (many) tactics;
  1680 
  1681 * HOL/inductive: Now also handles more general introduction rules such
  1682   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1683   theorems are now maintained within the theory (maintained via the
  1684   "mono" attribute);
  1685 
  1686 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1687   (using function types) such as
  1688 
  1689   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1690 
  1691 * HOL/record: record_simproc (part of the default simpset) takes care
  1692 of selectors applied to updated records; record_split_tac is no longer
  1693 part of the default claset; update_defs may now be removed from the
  1694 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1695 
  1696   claset_ref () := claset() addSWrapper record_split_wrapper;
  1697   Delsimprocs [record_simproc]
  1698 
  1699 * HOL/typedef: fixed type inference for representing set; type
  1700 arguments now have to occur explicitly on the rhs as type constraints;
  1701 
  1702 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1703 names rather than an ML expression;
  1704 
  1705 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1706 supplied later.  Program schemes can be defined, such as
  1707     "While B C s = (if B s then While B C (C s) else s)"
  1708 where the well-founded relation can be chosen after B and C have been given.
  1709 
  1710 * HOL/List: the constructors of type list are now Nil and Cons;
  1711 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1712 course, ML tools referring to List.list.op # etc. have to be adapted;
  1713 
  1714 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1715 disabled by default; run isabelle with option -m HOL to get back to
  1716 the original Gordon/HOL-style output;
  1717 
  1718 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1719 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1720 
  1721 * HOL basic syntax simplified (more orthogonal): all variants of
  1722 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1723 Eps operator is provided as well: "SOME x. P[x]";
  1724 
  1725 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1726 
  1727 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1728 thus available for user theories;
  1729 
  1730 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1731 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1732 time;
  1733 
  1734 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1735 several times and then mp;
  1736 
  1737 
  1738 *** LK ***
  1739 
  1740 * the notation <<...>> is now available as a notation for sequences of
  1741 formulas;
  1742 
  1743 * the simplifier is now installed
  1744 
  1745 * the axiom system has been generalized (thanks to Soren Heilmann)
  1746 
  1747 * the classical reasoner now has a default rule database
  1748 
  1749 
  1750 *** ZF ***
  1751 
  1752 * new primrec section allows primitive recursive functions to be given
  1753 directly (as in HOL) over datatypes and the natural numbers;
  1754 
  1755 * new tactics induct_tac and exhaust_tac for induction (or case
  1756 analysis) over datatypes and the natural numbers;
  1757 
  1758 * the datatype declaration of type T now defines the recursor T_rec;
  1759 
  1760 * simplification automatically does freeness reasoning for datatype
  1761 constructors;
  1762 
  1763 * automatic type-inference, with AddTCs command to insert new
  1764 type-checking rules;
  1765 
  1766 * datatype introduction rules are now added as Safe Introduction rules
  1767 to the claset;
  1768 
  1769 * the syntax "if P then x else y" is now available in addition to
  1770 if(P,x,y);
  1771 
  1772 
  1773 *** Internal programming interfaces ***
  1774 
  1775 * tuned simplifier trace output; new flag debug_simp;
  1776 
  1777 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1778 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1779 
  1780 * AxClass.axclass_tac lost the theory argument;
  1781 
  1782 * tuned current_goals_markers semantics: begin / end goal avoids
  1783 printing empty lines;
  1784 
  1785 * removed prs and prs_fn hook, which was broken because it did not
  1786 include \n in its semantics, forcing writeln to add one
  1787 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1788 string -> unit if you really want to output text without newline;
  1789 
  1790 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1791 plain output, interface builders may have to enable 'isabelle_font'
  1792 mode to get Isabelle font glyphs as before;
  1793 
  1794 * refined token_translation interface; INCOMPATIBILITY: output length
  1795 now of type real instead of int;
  1796 
  1797 * theory loader actions may be traced via new ThyInfo.add_hook
  1798 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1799 your own database of information attached to *whole* theories -- as
  1800 opposed to intra-theory data slots offered via TheoryDataFun;
  1801 
  1802 * proper handling of dangling sort hypotheses (at last!);
  1803 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1804 extra sort hypotheses that can be witnessed from the type signature;
  1805 the force_strip_shyps flag is gone, any remaining shyps are simply
  1806 left in the theorem (with a warning issued by strip_shyps_warning);
  1807 
  1808 
  1809 
  1810 New in Isabelle98-1 (October 1998)
  1811 ----------------------------------
  1812 
  1813 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1814 
  1815 * several changes of automated proof tools;
  1816 
  1817 * HOL: major changes to the inductive and datatype packages, including
  1818 some minor incompatibilities of theory syntax;
  1819 
  1820 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1821 called `inj_on';
  1822 
  1823 * HOL: removed duplicate thms in Arith:
  1824   less_imp_add_less  should be replaced by  trans_less_add1
  1825   le_imp_add_le      should be replaced by  trans_le_add1
  1826 
  1827 * HOL: unary minus is now overloaded (new type constraints may be
  1828 required);
  1829 
  1830 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1831 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1832 now taken as an integer constant.
  1833 
  1834 * Pure: ML function 'theory_of' renamed to 'theory';
  1835 
  1836 
  1837 *** Proof tools ***
  1838 
  1839 * Simplifier:
  1840   1. Asm_full_simp_tac is now more aggressive.
  1841      1. It will sometimes reorient premises if that increases their power to
  1842         simplify.
  1843      2. It does no longer proceed strictly from left to right but may also
  1844         rotate premises to achieve further simplification.
  1845      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1846      old Asm_full_simp_tac in that it does not rotate premises.
  1847   2. The simplifier now knows a little bit about nat-arithmetic.
  1848 
  1849 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1850 allows for selected deletion of wrappers, by introduction of names for
  1851 wrapper functionals.  This implies that addbefore, addSbefore,
  1852 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1853 and that adding two tactics with the same name overwrites the first
  1854 one (emitting a warning).
  1855   type wrapper = (int -> tactic) -> (int -> tactic)
  1856   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1857   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1858   delWrapper, delSWrapper: claset *  string            -> claset
  1859   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1860 
  1861 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1862 semantics; addbefore now affects only the unsafe part of step_tac
  1863 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1864 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1865 by Force_tac;
  1866 
  1867 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1868 compWrapper; added safe wrapper (and access functions for it);
  1869 
  1870 * HOL/split_all_tac is now much faster and fails if there is nothing
  1871 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1872 and the names of the automatically generated variables have changed.
  1873 split_all_tac has moved within claset() from unsafe wrappers to safe
  1874 wrappers, which means that !!-bound variables are split much more
  1875 aggressively, and safe_tac and clarify_tac now split such variables.
  1876 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1877 Note: the same holds for record_split_tac, which does the job of
  1878 split_all_tac for record fields.
  1879 
  1880 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1881 permanently to the default simpset using Addsplits just like
  1882 Addsimps. They can be removed via Delsplits just like
  1883 Delsimps. Lower-case versions are also available.
  1884 
  1885 * HOL/Simplifier: The rule split_if is now part of the default
  1886 simpset. This means that the simplifier will eliminate all occurrences
  1887 of if-then-else in the conclusion of a goal. To prevent this, you can
  1888 either remove split_if completely from the default simpset by
  1889 `Delsplits [split_if]' or remove it in a specific call of the
  1890 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1891 other case splitting rules to/from the default simpset: every datatype
  1892 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1893 t is the name of the datatype).
  1894 
  1895 * Classical reasoner / Simplifier combination: new force_tac (and
  1896 derivatives Force_tac, force) combines rewriting and classical
  1897 reasoning (and whatever other tools) similarly to auto_tac, but is
  1898 aimed to solve the given subgoal completely.
  1899 
  1900 
  1901 *** General ***
  1902 
  1903 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1904 and `goalw': the theory is no longer needed as an explicit argument -
  1905 the current theory context is used; assumptions are no longer returned
  1906 at the ML-level unless one of them starts with ==> or !!; it is
  1907 recommended to convert to these new commands using isatool fixgoal
  1908 (backup your sources first!);
  1909 
  1910 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1911 the current theory context, and 'theory' to lookup stored theories;
  1912 
  1913 * new theory section 'locale' for declaring constants, assumptions and
  1914 definitions that have local scope;
  1915 
  1916 * new theory section 'nonterminals' for purely syntactic types;
  1917 
  1918 * new theory section 'setup' for generic ML setup functions
  1919 (e.g. package initialization);
  1920 
  1921 * the distribution now includes Isabelle icons: see
  1922 lib/logo/isabelle-{small,tiny}.xpm;
  1923 
  1924 * isatool install - install binaries with absolute references to
  1925 ISABELLE_HOME/bin;
  1926 
  1927 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1928 
  1929 * print mode 'emacs' reserved for Isamode;
  1930 
  1931 * support multiple print (ast) translations per constant name;
  1932 
  1933 * theorems involving oracles are now printed with a suffixed [!];
  1934 
  1935 
  1936 *** HOL ***
  1937 
  1938 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1939 
  1940 * HOL/inductive package reorganized and improved: now supports mutual
  1941 definitions such as
  1942 
  1943   inductive EVEN ODD
  1944     intrs
  1945       null "0 : EVEN"
  1946       oddI "n : EVEN ==> Suc n : ODD"
  1947       evenI "n : ODD ==> Suc n : EVEN"
  1948 
  1949 new theorem list "elims" contains an elimination rule for each of the
  1950 recursive sets; inductive definitions now handle disjunctive premises
  1951 correctly (also ZF);
  1952 
  1953 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1954 "mutual_induct" no longer exists - the induction rule is always
  1955 contained in "induct";
  1956 
  1957 
  1958 * HOL/datatype package re-implemented and greatly improved: now
  1959 supports mutually recursive datatypes such as
  1960 
  1961   datatype
  1962     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1963             | SUM ('a aexp) ('a aexp)
  1964             | DIFF ('a aexp) ('a aexp)
  1965             | NUM 'a
  1966   and
  1967     'a bexp = LESS ('a aexp) ('a aexp)
  1968             | AND ('a bexp) ('a bexp)
  1969             | OR ('a bexp) ('a bexp)
  1970 
  1971 as well as indirectly recursive datatypes such as
  1972 
  1973   datatype
  1974     ('a, 'b) term = Var 'a
  1975                   | App 'b ((('a, 'b) term) list)
  1976 
  1977 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1978 induction on mutually / indirectly recursive datatypes.
  1979 
  1980 Primrec equations are now stored in theory and can be accessed via
  1981 <function_name>.simps.
  1982 
  1983 INCOMPATIBILITIES:
  1984 
  1985   - Theories using datatypes must now have theory Datatype as an
  1986     ancestor.
  1987   - The specific <typename>.induct_tac no longer exists - use the
  1988     generic induct_tac instead.
  1989   - natE has been renamed to nat.exhaust - use exhaust_tac
  1990     instead of res_inst_tac ... natE. Note that the variable
  1991     names in nat.exhaust differ from the names in natE, this
  1992     may cause some "fragile" proofs to fail.
  1993   - The theorems split_<typename>_case and split_<typename>_case_asm
  1994     have been renamed to <typename>.split and <typename>.split_asm.
  1995   - Since default sorts of type variables are now handled correctly,
  1996     some datatype definitions may have to be annotated with explicit
  1997     sort constraints.
  1998   - Primrec definitions no longer require function name and type
  1999     of recursive argument.
  2000 
  2001 Consider using isatool fixdatatype to adapt your theories and proof
  2002 scripts to the new package (backup your sources first!).
  2003 
  2004 
  2005 * HOL/record package: considerably improved implementation; now
  2006 includes concrete syntax for record types, terms, updates; theorems
  2007 for surjective pairing and splitting !!-bound record variables; proof
  2008 support is as follows:
  2009 
  2010   1) standard conversions (selectors or updates applied to record
  2011 constructor terms) are part of the standard simpset;
  2012 
  2013   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2014 made part of standard simpset and claset via addIffs;
  2015 
  2016   3) a tactic for record field splitting (record_split_tac) is part of
  2017 the standard claset (addSWrapper);
  2018 
  2019 To get a better idea about these rules you may retrieve them via
  2020 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2021 the name of your record type.
  2022 
  2023 The split tactic 3) conceptually simplifies by the following rule:
  2024 
  2025   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2026 
  2027 Thus any record variable that is bound by meta-all will automatically
  2028 blow up into some record constructor term, consequently the
  2029 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2030 solve record problems automatically.
  2031 
  2032 
  2033 * reorganized the main HOL image: HOL/Integ and String loaded by
  2034 default; theory Main includes everything;
  2035 
  2036 * automatic simplification of integer sums and comparisons, using cancellation;
  2037 
  2038 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2039 
  2040 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2041 
  2042 * many new identities for unions, intersections, set difference, etc.;
  2043 
  2044 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2045 called split_if, split_split, split_sum_case and split_nat_case (to go
  2046 with add/delsplits);
  2047 
  2048 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2049 (?x::unit) = (); this is made part of the default simpset, which COULD
  2050 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2051 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2052 unit_abs_eta_conv is added in order to counter the effect of
  2053 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2054 %u.f();
  2055 
  2056 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2057 makes more sense);
  2058 
  2059 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2060   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2061   disjointness reasoning but breaking a few old proofs.
  2062 
  2063 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2064 to 'converse' from 'inverse' (for compatibility with ZF and some
  2065 literature);
  2066 
  2067 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2068 the well-founded relation;
  2069 
  2070 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2071     Compl A.  The "Compl" syntax remains available as input syntax for this
  2072     release ONLY.
  2073 
  2074 * HOL/Update: new theory of function updates:
  2075     f(a:=b) == %x. if x=a then b else f x
  2076 may also be iterated as in f(a:=b,c:=d,...);
  2077 
  2078 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2079 
  2080 * HOL/List:
  2081   - new function list_update written xs[i:=v] that updates the i-th
  2082     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2083   - new function `upt' written [i..j(] which generates the list
  2084     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2085     bound write [i..j], which is a shorthand for [i..j+1(].
  2086   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2087 
  2088 * HOL/Arith:
  2089   - removed 'pred' (predecessor) function;
  2090   - generalized some theorems about n-1;
  2091   - many new laws about "div" and "mod";
  2092   - new laws about greatest common divisors (see theory ex/Primes);
  2093 
  2094 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2095 instead of "inverse";
  2096 
  2097 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2098   of the multiset ordering;
  2099 
  2100 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2101   (not included by default);
  2102 
  2103 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2104 
  2105 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2106   programs, i.e. different program variables may have different types.
  2107 
  2108 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2109   [previously, this check worked only if the rewrite rule was unconditional]
  2110   Now rew can involve either definitions or equalities (either == or =).
  2111 
  2112 
  2113 *** ZF ***
  2114 
  2115 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2116   only the theorems proved on ZF.ML;
  2117 
  2118 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2119   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2120   disjointness reasoning but breaking a few old proofs.
  2121 
  2122 * ZF/Update: new theory of function updates
  2123     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2124   may also be iterated as in f(a:=b,c:=d,...);
  2125 
  2126 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2127 
  2128 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2129   [previously, this check worked only if the rewrite rule was unconditional]
  2130   Now rew can involve either definitions or equalities (either == or =).
  2131 
  2132 * case_tac provided for compatibility with HOL
  2133     (like the old excluded_middle_tac, but with subgoals swapped)
  2134 
  2135 
  2136 *** Internal programming interfaces ***
  2137 
  2138 * Pure: several new basic modules made available for general use, see
  2139 also src/Pure/README;
  2140 
  2141 * improved the theory data mechanism to support encapsulation (data
  2142 kind name replaced by private Object.kind, acting as authorization
  2143 key); new type-safe user interface via functor TheoryDataFun; generic
  2144 print_data function becomes basically useless;
  2145 
  2146 * removed global_names compatibility flag -- all theory declarations
  2147 are qualified by default;
  2148 
  2149 * module Pure/Syntax now offers quote / antiquote translation
  2150 functions (useful for Hoare logic etc. with implicit dependencies);
  2151 see HOL/ex/Antiquote for an example use;
  2152 
  2153 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2154 cterm -> thm;
  2155 
  2156 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2157 subgoal;
  2158 
  2159 * Display.print_goals function moved to Locale.print_goals;
  2160 
  2161 * standard print function for goals supports current_goals_markers
  2162 variable for marking begin of proof, end of proof, start of goal; the
  2163 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2164 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2165 for example;
  2166 
  2167 
  2168 
  2169 New in Isabelle98 (January 1998)
  2170 --------------------------------
  2171 
  2172 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2173 
  2174 * changed lexical syntax of terms / types: dots made part of long
  2175 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2176 
  2177 * simpset (and claset) reference variable replaced by functions
  2178 simpset / simpset_ref;
  2179 
  2180 * no longer supports theory aliases (via merge) and non-trivial
  2181 implicit merge of thms' signatures;
  2182 
  2183 * most internal names of constants changed due to qualified names;
  2184 
  2185 * changed Pure/Sequence interface (see Pure/seq.ML);
  2186 
  2187 
  2188 *** General Changes ***
  2189 
  2190 * hierachically structured name spaces (for consts, types, axms, thms
  2191 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2192 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2193 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2194 long_names for fully qualified output names; NOTE: ML programs
  2195 (special tactics, packages etc.) referring to internal names may have
  2196 to be adapted to cope with fully qualified names; in case of severe
  2197 backward campatibility problems try setting 'global_names' at compile
  2198 time to have enrything declared within a flat name space; one may also
  2199 fine tune name declarations in theories via the 'global' and 'local'
  2200 section;
  2201 
  2202 * reimplemented the implicit simpset and claset using the new anytype
  2203 data filed in signatures; references simpset:simpset ref etc. are
  2204 replaced by functions simpset:unit->simpset and
  2205 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2206 to patch your ML files accordingly;
  2207 
  2208 * HTML output now includes theory graph data for display with Java
  2209 applet or isatool browser; data generated automatically via isatool
  2210 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2211 
  2212 * defs may now be conditional; improved rewrite_goals_tac to handle
  2213 conditional equations;
  2214 
  2215 * defs now admits additional type arguments, using TYPE('a) syntax;
  2216 
  2217 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2218 creates a new theory node; implicit merge of thms' signatures is
  2219 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2220 transfer:theory->thm->thm in (rare) cases;
  2221 
  2222 * improved handling of draft signatures / theories; draft thms (and
  2223 ctyps, cterms) are automatically promoted to real ones;
  2224 
  2225 * slightly changed interfaces for oracles: admit many per theory, named
  2226 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2227 
  2228 * print_goals: optional output of const types (set show_consts and
  2229 show_types);
  2230 
  2231 * improved output of warnings (###) and errors (***);
  2232 
  2233 * subgoal_tac displays a warning if the new subgoal has type variables;
  2234 
  2235 * removed old README and Makefiles;
  2236 
  2237 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2238 
  2239 * removed obsolete init_pps and init_database;
  2240 
  2241 * deleted the obsolete tactical STATE, which was declared by
  2242     fun STATE tacfun st = tacfun st st;
  2243 
  2244 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2245 (which abbreviates $HOME);
  2246 
  2247 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2248 use isatool fixseq to adapt your ML programs (this works for fully
  2249 qualified references to the Sequence structure only!);
  2250 
  2251 * use_thy no longer requires writable current directory; it always
  2252 reloads .ML *and* .thy file, if either one is out of date;
  2253 
  2254 
  2255 *** Classical Reasoner ***
  2256 
  2257 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2258 tactics that use classical reasoning to simplify a subgoal without
  2259 splitting it into several subgoals;
  2260 
  2261 * Safe_tac: like safe_tac but uses the default claset;
  2262 
  2263 
  2264 *** Simplifier ***
  2265 
  2266 * added simplification meta rules:
  2267     (asm_)(full_)simplify: simpset -> thm -> thm;
  2268 
  2269 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2270 logics (again);
  2271 
  2272 * added prems argument to simplification procedures;
  2273 
  2274 * HOL, FOL, ZF: added infix function `addsplits':
  2275   instead of `<simpset> setloop (split_tac <thms>)'
  2276   you can simply write `<simpset> addsplits <thms>'
  2277 
  2278 
  2279 *** Syntax ***
  2280 
  2281 * TYPE('a) syntax for type reflection terms;
  2282 
  2283 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2284 
  2285 * pretty printer: changed order of mixfix annotation preference (again!);
  2286 
  2287 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2288 
  2289 
  2290 *** HOL ***
  2291 
  2292 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2293   with `addloop' of the simplifier to faciliate case splitting in premises.
  2294 
  2295 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2296 
  2297 * HOL/Auth: new protocol proofs including some for the Internet
  2298   protocol TLS;
  2299 
  2300 * HOL/Map: new theory of `maps' a la VDM;
  2301 
  2302 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2303 cancelling out common nat summands from =, <, <= (in)equalities, or
  2304 differences; simplification procedures nat_cancel_factor for
  2305 cancelling common factor from =, <, <= (in)equalities over natural
  2306 sums; nat_cancel contains both kinds of procedures, it is installed by
  2307 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2308 
  2309 * HOL/simplifier: terms of the form
  2310   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2311   are rewritten to
  2312   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2313   and those of the form
  2314   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2315   are rewritten to
  2316   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2317 
  2318 * HOL/datatype
  2319   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2320 
  2321   P(t_case f1 ... fn x) =
  2322      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2323         ...
  2324        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2325      )
  2326 
  2327   and a theorem `split_t_case_asm' of the form
  2328 
  2329   P(t_case f1 ... fn x) =
  2330     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2331         ...
  2332        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2333      )
  2334   which can be added to a simpset via `addsplits'. The existing theorems
  2335   expand_list_case and expand_option_case have been renamed to
  2336   split_list_case and split_option_case.
  2337 
  2338 * HOL/Arithmetic:
  2339   - `pred n' is automatically converted to `n-1'.
  2340     Users are strongly encouraged not to use `pred' any longer,
  2341     because it will disappear altogether at some point.
  2342   - Users are strongly encouraged to write "0 < n" rather than
  2343     "n ~= 0". Theorems and proof tools have been modified towards this
  2344     `standard'.
  2345 
  2346 * HOL/Lists:
  2347   the function "set_of_list" has been renamed "set" (and its theorems too);
  2348   the function "nth" now takes its arguments in the reverse order and
  2349   has acquired the infix notation "!" as in "xs!n".
  2350 
  2351 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2352 
  2353 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2354   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2355 
  2356 * HOL/record: extensible records with schematic structural subtyping
  2357 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2358 still lacks various theorems and concrete record syntax;
  2359 
  2360 
  2361 *** HOLCF ***
  2362 
  2363 * removed "axioms" and "generated by" sections;
  2364 
  2365 * replaced "ops" section by extended "consts" section, which is capable of
  2366   handling the continuous function space "->" directly;
  2367 
  2368 * domain package:
  2369   . proves theorems immediately and stores them in the theory,
  2370   . creates hierachical name space,
  2371   . now uses normal mixfix annotations (instead of cinfix...),
  2372   . minor changes to some names and values (for consistency),
  2373   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2374   . separator between mutual domain defs: changed "," to "and",
  2375   . improved handling of sort constraints;  now they have to
  2376     appear on the left-hand side of the equations only;
  2377 
  2378 * fixed LAM <x,y,zs>.b syntax;
  2379 
  2380 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2381 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2382 
  2383 
  2384 *** FOL and ZF ***
  2385 
  2386 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2387   with `addloop' of the simplifier to faciliate case splitting in premises.
  2388 
  2389 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2390 in HOL, they strip ALL and --> from proved theorems;
  2391 
  2392 
  2393 
  2394 New in Isabelle94-8 (May 1997)
  2395 ------------------------------
  2396 
  2397 *** General Changes ***
  2398 
  2399 * new utilities to build / run / maintain Isabelle etc. (in parts
  2400 still somewhat experimental); old Makefiles etc. still functional;
  2401 
  2402 * new 'Isabelle System Manual';
  2403 
  2404 * INSTALL text, together with ./configure and ./build scripts;
  2405 
  2406 * reimplemented type inference for greater efficiency, better error
  2407 messages and clean internal interface;
  2408 
  2409 * prlim command for dealing with lots of subgoals (an easier way of
  2410 setting goals_limit);
  2411 
  2412 
  2413 *** Syntax ***
  2414 
  2415 * supports alternative (named) syntax tables (parser and pretty
  2416 printer); internal interface is provided by add_modesyntax(_i);
  2417 
  2418 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2419 be used in conjunction with the Isabelle symbol font; uses the
  2420 "symbols" syntax table;
  2421 
  2422 * added token_translation interface (may translate name tokens in
  2423 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2424 the current print_mode); IMPORTANT: user print translation functions
  2425 are responsible for marking newly introduced bounds
  2426 (Syntax.mark_boundT);
  2427 
  2428 * token translations for modes "xterm" and "xterm_color" that display
  2429 names in bold, underline etc. or colors (which requires a color
  2430 version of xterm);
  2431 
  2432 * infixes may now be declared with names independent of their syntax;
  2433 
  2434 * added typed_print_translation (like print_translation, but may
  2435 access type of constant);
  2436 
  2437 
  2438 *** Classical Reasoner ***
  2439 
  2440 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2441 some limitations.  Blast_tac...
  2442   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2443   + ignores elimination rules that don't have the correct format
  2444         (the conclusion MUST be a formula variable)
  2445   + ignores types, which can make HOL proofs fail
  2446   + rules must not require higher-order unification, e.g. apply_type in ZF
  2447     [message "Function Var's argument not a bound variable" relates to this]
  2448   + its proof strategy is more general but can actually be slower
  2449 
  2450 * substitution with equality assumptions no longer permutes other
  2451 assumptions;
  2452 
  2453 * minor changes in semantics of addafter (now called addaltern); renamed
  2454 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2455 (and access functions for it);
  2456 
  2457 * improved combination of classical reasoner and simplifier:
  2458   + functions for handling clasimpsets
  2459   + improvement of addss: now the simplifier is called _after_ the
  2460     safe steps.
  2461   + safe variant of addss called addSss: uses safe simplifications
  2462     _during_ the safe steps. It is more complete as it allows multiple
  2463     instantiations of unknowns (e.g. with slow_tac).
  2464 
  2465 *** Simplifier ***
  2466 
  2467 * added interface for simplification procedures (functions that
  2468 produce *proven* rewrite rules on the fly, depending on current
  2469 redex);
  2470 
  2471 * ordering on terms as parameter (used for ordered rewriting);
  2472 
  2473 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2474 
  2475 * the solver is now split into a safe and an unsafe part.
  2476 This should be invisible for the normal user, except that the
  2477 functions setsolver and addsolver have been renamed to setSolver and
  2478 addSolver; added safe_asm_full_simp_tac;
  2479 
  2480 
  2481 *** HOL ***
  2482 
  2483 * a generic induction tactic `induct_tac' which works for all datatypes and
  2484 also for type `nat';
  2485 
  2486 * a generic case distinction tactic `exhaust_tac' which works for all
  2487 datatypes and also for type `nat';
  2488 
  2489 * each datatype comes with a function `size';
  2490 
  2491 * patterns in case expressions allow tuple patterns as arguments to
  2492 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2493 
  2494 * primrec now also works with type nat;
  2495 
  2496 * recdef: a new declaration form, allows general recursive functions to be
  2497 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2498 
  2499 * the constant for negation has been renamed from "not" to "Not" to
  2500 harmonize with FOL, ZF, LK, etc.;
  2501 
  2502 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2503 infinite lists;
  2504 
  2505 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2506 
  2507 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2508 problems in commutative rings, using axiomatic type classes for + and *;
  2509 
  2510 * more examples in HOL/MiniML and HOL/Auth;
  2511 
  2512 * more default rewrite rules for quantifiers, union/intersection;
  2513 
  2514 * a new constant `arbitrary == @x.False';
  2515 
  2516 * HOLCF/IOA replaces old HOL/IOA;
  2517 
  2518 * HOLCF changes: derived all rules and arities
  2519   + axiomatic type classes instead of classes
  2520   + typedef instead of faking type definitions
  2521   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2522   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2523   + eliminated the types void, one, tr
  2524   + use unit lift and bool lift (with translations) instead of one and tr
  2525   + eliminated blift from Lift3.thy (use Def instead of blift)
  2526   all eliminated rules are derived as theorems --> no visible changes ;
  2527 
  2528 
  2529 *** ZF ***
  2530 
  2531 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2532 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2533 as ZF_cs addSIs [equalityI];
  2534 
  2535 
  2536 
  2537 New in Isabelle94-7 (November 96)
  2538 ---------------------------------
  2539 
  2540 * allowing negative levels (as offsets) in prlev and choplev;
  2541 
  2542 * super-linear speedup for large simplifications;
  2543 
  2544 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2545 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2546 FAIL); can suppress it using the command Delsimps (ex_simps @
  2547 all_simps); De Morgan laws are also now included, by default;
  2548 
  2549 * improved printing of ==>  :  ~:
  2550 
  2551 * new object-logic "Sequents" adds linear logic, while replacing LK
  2552 and Modal (thanks to Sara Kalvala);
  2553 
  2554 * HOL/Auth: correctness proofs for authentication protocols;
  2555 
  2556 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2557 examples on HOL/Auth);
  2558 
  2559 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2560 the rewriter and classical reasoner simultaneously;
  2561 
  2562 * function uresult no longer returns theorems in "standard" format;
  2563 regain previous version by: val uresult = standard o uresult;
  2564 
  2565 
  2566 
  2567 New in Isabelle94-6
  2568 -------------------
  2569 
  2570 * oracles -- these establish an interface between Isabelle and trusted
  2571 external reasoners, which may deliver results as theorems;
  2572 
  2573 * proof objects (in particular record all uses of oracles);
  2574 
  2575 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2576 
  2577 * "constdefs" section in theory files;
  2578 
  2579 * "primrec" section (HOL) no longer requires names;
  2580 
  2581 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2582 
  2583 
  2584 
  2585 New in Isabelle94-5
  2586 -------------------
  2587 
  2588 * reduced space requirements;
  2589 
  2590 * automatic HTML generation from theories;
  2591 
  2592 * theory files no longer require "..." (quotes) around most types;
  2593 
  2594 * new examples, including two proofs of the Church-Rosser theorem;
  2595 
  2596 * non-curried (1994) version of HOL is no longer distributed;
  2597 
  2598 
  2599 
  2600 New in Isabelle94-4
  2601 -------------------
  2602 
  2603 * greatly reduced space requirements;
  2604 
  2605 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2606 
  2607 * searchable theorem database (see the section "Retrieving theorems" on
  2608 page 8 of the Reference Manual);
  2609 
  2610 * new examples, including Grabczewski's monumental case study of the
  2611 Axiom of Choice;
  2612 
  2613 * The previous version of HOL renamed to Old_HOL;
  2614 
  2615 * The new version of HOL (previously called CHOL) uses a curried syntax
  2616 for functions.  Application looks like f a b instead of f(a,b);
  2617 
  2618 * Mutually recursive inductive definitions finally work in HOL;
  2619 
  2620 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2621 translates to the operator "split";
  2622 
  2623 
  2624 
  2625 New in Isabelle94-3
  2626 -------------------
  2627 
  2628 * new infix operator, addss, allowing the classical reasoner to
  2629 perform simplification at each step of its search.  Example:
  2630         fast_tac (cs addss ss)
  2631 
  2632 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2633 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2634 look like (a,b) instead of <a,b>;
  2635 
  2636 * PLEASE NOTE: CHOL will eventually replace HOL!
  2637 
  2638 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2639 It translates to the operator "split".  A new theory of integers is available;
  2640 
  2641 * In ZF, integer numerals now denote two's-complement binary integers.
  2642 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2643 
  2644 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2645 of the Axiom of Choice;
  2646 
  2647 
  2648 
  2649 New in Isabelle94-2
  2650 -------------------
  2651 
  2652 * Significantly faster resolution;
  2653 
  2654 * the different sections in a .thy file can now be mixed and repeated
  2655 freely;
  2656 
  2657 * Database of theorems for FOL, HOL and ZF.  New
  2658 commands including qed, qed_goal and bind_thm store theorems in the database.
  2659 
  2660 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2661 a given theory (thms_of), or find out what theory a theorem was proved in
  2662 (theory_of_thm);
  2663 
  2664 * Bugs fixed in the inductive definition and datatype packages;
  2665 
  2666 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2667 and HOL_dup_cs obsolete;
  2668 
  2669 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2670 have been removed;
  2671 
  2672 * Simpler definition of function space in ZF;
  2673 
  2674 * new results about cardinal and ordinal arithmetic in ZF;
  2675 
  2676 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2677 types;
  2678 
  2679 
  2680 $Id$