NEWS
author wenzelm
Thu Jun 10 20:11:51 2004 +0200 (2004-06-10)
changeset 14917 b54b11ebe220
parent 14897 577f95db94e4
child 14919 0f5fde03e2b5
permissions -rw-r--r--
tuned;
     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: clear separation of logical types and nonterminals, where the
    28   latter may only occur in 'syntax' specifications or type
    29   abbreviations.  Before that distinction was only partially
    30   implemented via type class "logic" vs. "{}".  Potential
    31   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    32   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    33   specifications may require further adaption (e.g. Cube/Base.thy).
    34 
    35 * Pure: removed obsolete type class "logic", use the top sort {}
    36   instead.  Note that non-logical types should be declared as
    37   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    38   object-logic specifications.
    39 
    40 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    41 
    42 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    43   specified in mixfix annotations as "(00...)".
    44 
    45 * Pure/Syntax: 'advanced' translation functions (parse_translation
    46   etc.) may depend on the signature of the theory context being
    47   presently used for parsing/printing, see also isar-ref manual.
    48 
    49 * Pure: tuned internal renaming of symbolic identifiers -- attach
    50   primes instead of base 26 numbers.
    51 
    52 * Document preparation: antiquotations now provide the option
    53   'locale=NAME' to specify an alternative context used for evaluating
    54   and printing the subsequent argument, as in @{thm [locale=LC]
    55   fold_commute}, for example.  Note that a proof context is escaped to
    56   the enclosing theory context first.
    57 
    58 * ML: output via the Isabelle channels of writeln/warning/error
    59   etc. is now passed through Output.output, with a hook for arbitrary
    60   transformations depending on the print_mode (cf. Output.add_mode --
    61   the first active mode that provides a output function wins).
    62   Already formatted output may be embedded into further text via
    63   Output.raw; the result of Pretty.string_of/str_of and derived
    64   functions (string_of_term/cterm/thm etc.) is already marked raw to
    65   accommodate easy composition of diagnostic messages etc.
    66   Programmers rarely need to care about Output.output or Output.raw at
    67   all, with some notable exceptions: Output.output is required when
    68   bypassing the standard channels (writeln etc.), or in token
    69   translations to produce properly formatted results; Output.raw is
    70   required when capturing already output material that will eventually
    71   be presented to the user a second time.
    72 
    73 
    74 *** HOL ***
    75 
    76 * HOL/record: reimplementation of records. Improved scalability for
    77   records with many fields, avoiding performance problems for type
    78   inference. Records are no longer composed of nested field types, but
    79   of nested extension types. Therefore the record type only grows
    80   linear in the number of extensions and not in the number of fields.
    81   The top-level (users) view on records is preserved.  Potential
    82   INCOMPATIBILITY only in strange cases, where the theory depends on
    83   the old record representation. The type generated for a record is
    84   called <record_name>_ext_type.
    85 
    86 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
    87 
    88   syntax (epsilon)
    89     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
    90 
    91   The symbol \<some> is displayed as the alternative epsilon of LaTeX
    92   and x-symbol; use option '-m epsilon' to get it actually printed.
    93   Moreover, the mathematically important symbolic identifier
    94   \<epsilon> becomes available as variable, constant etc.
    95 
    96 * Simplifier: "record_upd_simproc" for simplification of multiple
    97   record updates enabled by default.  INCOMPATIBILITY: old proofs
    98   break occasionally, since simplification is more powerful by
    99   default.
   100 
   101 
   102 *** HOLCF ***
   103 
   104 * HOLCF: discontinued special version of 'constdefs' (which used to
   105   support continuous functions) in favor of the general Pure one with
   106   full type-inference.
   107 
   108 
   109 *** ZF ***
   110 
   111 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the First
   112   Isomorphism Theorem (on quotienting by the kernel of a homomorphism).
   113 
   114 
   115 
   116 New in Isabelle2004 (April 2004)
   117 --------------------------------
   118 
   119 *** General ***
   120 
   121 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   122   Replaces linorder.ML.
   123 
   124 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   125   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   126   (\<a>...\<z>), are now considered normal letters, and can therefore
   127   be used anywhere where an ASCII letter (a...zA...Z) has until
   128   now. COMPATIBILITY: This obviously changes the parsing of some
   129   terms, especially where a symbol has been used as a binder, say
   130   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   131   as an identifier.  Fix it by inserting a space around former
   132   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   133   existing theory and ML files.
   134 
   135 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   136 
   137 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   138   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   139   a normal (but invisible) letter. For multiple letter subscripts repeat
   140   \<^isub> like this: x\<^isub>1\<^isub>2.
   141 
   142 * Pure: There are now sub-/superscripts that can span more than one
   143   character. Text between \<^bsub> and \<^esub> is set in subscript in
   144   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   145   superscript. The new control characters are not identifier parts.
   146 
   147 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   148   content of "..." to the latex file instead of \isacntrl... . The "..."
   149   may consist of any printable characters excluding the end bracket >.
   150 
   151 * Pure: Using new Isar command "finalconsts" (or the ML functions
   152   Theory.add_finals or Theory.add_finals_i) it is now possible to
   153   declare constants "final", which prevents their being given a definition
   154   later.  It is useful for constants whose behaviour is fixed axiomatically
   155   rather than definitionally, such as the meta-logic connectives.
   156 
   157 * Pure: 'instance' now handles general arities with general sorts
   158   (i.e. intersections of classes),
   159 
   160 * Presentation: generated HTML now uses a CSS style sheet to make layout
   161   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   162   It can be changed to alter the colors/layout of generated pages.
   163 
   164 
   165 *** Isar ***
   166 
   167 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   168   cut_tac, subgoal_tac and thin_tac:
   169   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   170     locales are no longer forced to write Isar proof scripts.
   171     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   172     emulations.
   173   - INCOMPATIBILITY: names of variables to be instantiated may no
   174     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   175     This is consistent with the instantiation attribute "where".
   176 
   177 * Attributes "where" and "of":
   178   - Now take type variables of instantiated theorem into account when reading
   179     the instantiation string.  This fixes a bug that caused instantiated
   180     theorems to have too special types in some circumstances.
   181   - "where" permits explicit instantiations of type variables.
   182 
   183 * Calculation commands "moreover" and "also" no longer interfere with
   184   current facts ("this"), admitting arbitrary combinations with "then"
   185   and derived forms.
   186 
   187 * Locales:
   188   - Goal statements involving the context element "includes" no longer
   189     generate theorems with internal delta predicates (those ending on
   190     "_axioms") in the premise.
   191     Resolve particular premise with <locale>.intro to obtain old form.
   192   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   193     specification and "includes" elements in goal statement.
   194   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   195     [intro?] and [elim?] (respectively) by default.
   196   - Experimental command for instantiation of locales in proof contexts:
   197         instantiate <label>[<attrs>]: <loc>
   198     Instantiates locale <loc> and adds all its theorems to the current context
   199     taking into account their attributes.  Label and attrs are optional
   200     modifiers, like in theorem declarations.  If present, names of
   201     instantiated theorems are qualified with <label>, and the attributes
   202     <attrs> are applied after any attributes these theorems might have already.
   203       If the locale has assumptions, a chained fact of the form
   204     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   205     are derived.  The command does not support old-style locales declared
   206     with "locale (open)".
   207       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   208 
   209 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   210   (Isar) contexts.
   211 
   212 
   213 *** HOL ***
   214 
   215 * Proof import: new image HOL4 contains the imported library from
   216   the HOL4 system with about 2500 theorems. It is imported by
   217   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   218   can be used like any other Isabelle image.  See
   219   HOL/Import/HOL/README for more information.
   220 
   221 * Simplifier:
   222   - Much improved handling of linear and partial orders.
   223     Reasoners for linear and partial orders are set up for type classes
   224     "linorder" and "order" respectively, and are added to the default simpset
   225     as solvers.  This means that the simplifier can build transitivity chains
   226     to solve goals from the assumptions.
   227   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   228     of blast or auto after simplification become unnecessary because the goal
   229     is solved by simplification already.
   230 
   231 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   232     all proved in axiomatic type classes for semirings, rings and fields.
   233 
   234 * Numerics:
   235   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   236     now formalized using the Ring_and_Field theory mentioned above.
   237   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   238     than before, because now they are set up once in a generic manner.
   239   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   240     Look for the general versions in Ring_and_Field (and Power if they concern
   241     exponentiation).
   242 
   243 * Type "rat" of the rational numbers is now available in HOL-Complex.
   244 
   245 * Records:
   246   - Record types are now by default printed with their type abbreviation
   247     instead of the list of all field types. This can be configured via
   248     the reference "print_record_type_abbr".
   249   - Simproc "record_upd_simproc" for simplification of multiple updates added
   250     (not enabled by default).
   251   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   252     EX x. x = sel r to True (not enabled by default).
   253   - Tactic "record_split_simp_tac" to split and simplify records added.
   254 
   255 * 'specification' command added, allowing for definition by
   256   specification.  There is also an 'ax_specification' command that
   257   introduces the new constants axiomatically.
   258 
   259 * arith(_tac) is now able to generate counterexamples for reals as well.
   260 
   261 * HOL-Algebra: new locale "ring" for non-commutative rings.
   262 
   263 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   264   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   265 
   266 * HOL-Matrix: a first theory for matrices in HOL with an application of
   267   matrix theory to linear programming.
   268 
   269 * Unions and Intersections:
   270   The x-symbol output syntax of UN and INT has been changed
   271   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   272   i.e. the index formulae has become a subscript, like in normal math.
   273   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   274   The subscript version is also accepted as input syntax.
   275 
   276 * Unions and Intersections over Intervals:
   277   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   278   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   279   like in normal math, and corresponding versions for < and for intersection.
   280 
   281 * ML: the legacy theory structures Int and List have been removed. They had
   282   conflicted with ML Basis Library structures having the same names.
   283 
   284 * 'refute' command added to search for (finite) countermodels.  Only works
   285   for a fragment of HOL.  The installation of an external SAT solver is
   286   highly recommended.  See "HOL/Refute.thy" for details.
   287 
   288 * 'quickcheck' command: Allows to find counterexamples by evaluating
   289   formulae under an assignment of free variables to random values.
   290   In contrast to 'refute', it can deal with inductive datatypes,
   291   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   292   for examples.
   293 
   294 
   295 *** HOLCF ***
   296 
   297 * Streams now come with concatenation and are part of the HOLCF image
   298 
   299 
   300 
   301 New in Isabelle2003 (May 2003)
   302 ------------------------------
   303 
   304 *** General ***
   305 
   306 * Provers/simplifier:
   307 
   308   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   309     Assumptions are now subject to complete mutual simplification,
   310     not just from left to right. The simplifier now preserves
   311     the order of assumptions.
   312 
   313     Potential INCOMPATIBILITY:
   314 
   315     -- simp sometimes diverges where the old version did
   316        not, e.g. invoking simp on the goal
   317 
   318         [| P (f x); y = x; f x = f y |] ==> Q
   319 
   320        now gives rise to the infinite reduction sequence
   321 
   322         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   323 
   324        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   325        kind of problem.
   326 
   327     -- Tactics combining classical reasoner and simplification (such as auto)
   328        are also affected by this change, because many of them rely on
   329        simp. They may sometimes diverge as well or yield a different numbers
   330        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   331        in case of problems. Sometimes subsequent calls to the classical
   332        reasoner will fail because a preceeding call to the simplifier too
   333        eagerly simplified the goal, e.g. deleted redundant premises.
   334 
   335   - The simplifier trace now shows the names of the applied rewrite rules
   336 
   337   - You can limit the number of recursive invocations of the simplifier
   338     during conditional rewriting (where the simplifie tries to solve the
   339     conditions before applying the rewrite rule):
   340     ML "simp_depth_limit := n"
   341     where n is an integer. Thus you can force termination where previously
   342     the simplifier would diverge.
   343 
   344   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   345 
   346   - No longer aborts on failed congruence proof.  Instead, the
   347     congruence is ignored.
   348 
   349 * Pure: New generic framework for extracting programs from constructive
   350   proofs. See HOL/Extraction.thy for an example instantiation, as well
   351   as HOL/Extraction for some case studies.
   352 
   353 * Pure: The main goal of the proof state is no longer shown by default, only
   354 the subgoals. This behaviour is controlled by a new flag.
   355    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   356 (ML: Proof.show_main_goal).
   357 
   358 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   359 rules whose conclusion matches subgoal 1:
   360       PG menu: Isabelle/Isar -> Show me -> matching rules
   361 The rules are ordered by how closely they match the subgoal.
   362 In particular, rules that solve a subgoal outright are displayed first
   363 (or rather last, the way they are printed).
   364 (ML: ProofGeneral.print_intros())
   365 
   366 * Pure: New flag trace_unify_fail causes unification to print
   367 diagnostic information (PG: in trace buffer) when it fails. This is
   368 useful for figuring out why single step proofs like rule, erule or
   369 assumption failed.
   370 
   371 * Pure: Locale specifications now produce predicate definitions
   372 according to the body of text (covering assumptions modulo local
   373 definitions); predicate "loc_axioms" covers newly introduced text,
   374 while "loc" is cumulative wrt. all included locale expressions; the
   375 latter view is presented only on export into the global theory
   376 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   377 on the old view without predicates;
   378 
   379 * Pure: predefined locales "var" and "struct" are useful for sharing
   380 parameters (as in CASL, for example); just specify something like
   381 ``var x + var y + struct M'' as import;
   382 
   383 * Pure: improved thms_containing: proper indexing of facts instead of
   384 raw theorems; check validity of results wrt. current name space;
   385 include local facts of proof configuration (also covers active
   386 locales), cover fixed variables in index; may use "_" in term
   387 specification; an optional limit for the number of printed facts may
   388 be given (the default is 40);
   389 
   390 * Pure: disallow duplicate fact bindings within new-style theory files
   391 (batch-mode only);
   392 
   393 * Provers: improved induct method: assumptions introduced by case
   394 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   395 the goal statement); "foo" still refers to all facts collectively;
   396 
   397 * Provers: the function blast.overloaded has been removed: all constants
   398 are regarded as potentially overloaded, which improves robustness in exchange
   399 for slight decrease in efficiency;
   400 
   401 * Provers/linorder: New generic prover for transitivity reasoning over
   402 linear orders.  Note: this prover is not efficient!
   403 
   404 * Isar: preview of problems to finish 'show' now produce an error
   405 rather than just a warning (in interactive mode);
   406 
   407 
   408 *** HOL ***
   409 
   410 * arith(_tac)
   411 
   412  - Produces a counter example if it cannot prove a goal.
   413    Note that the counter example may be spurious if the goal is not a formula
   414    of quantifier-free linear arithmetic.
   415    In ProofGeneral the counter example appears in the trace buffer.
   416 
   417  - Knows about div k and mod k where k is a numeral of type nat or int.
   418 
   419  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   420    linear arithmetic fails. This takes account of quantifiers and divisibility.
   421    Presburger arithmetic can also be called explicitly via presburger(_tac).
   422 
   423 * simp's arithmetic capabilities have been enhanced a bit: it now
   424 takes ~= in premises into account (by performing a case split);
   425 
   426 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   427 are distributed over a sum of terms;
   428 
   429 * New tactic "trans_tac" and method "trans" instantiate
   430 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   431 "<=", "<" and "=").
   432 
   433 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   434 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   435 
   436 * 'typedef' command has new option "open" to suppress the set
   437 definition;
   438 
   439 * functions Min and Max on finite sets have been introduced (theory
   440 Finite_Set);
   441 
   442 * attribute [symmetric] now works for relations as well; it turns
   443 (x,y) : R^-1 into (y,x) : R, and vice versa;
   444 
   445 * induct over a !!-quantified statement (say !!x1..xn):
   446   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   447 
   448 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   449 %x. None. Warning: empty_def now refers to the previously hidden definition
   450 of the empty set.
   451 
   452 * Algebra: formalization of classical algebra.  Intended as base for
   453 any algebraic development in Isabelle.  Currently covers group theory
   454 (up to Sylow's theorem) and ring theory (Universal Property of
   455 Univariate Polynomials).  Contributions welcome;
   456 
   457 * GroupTheory: deleted, since its material has been moved to Algebra;
   458 
   459 * Complex: new directory of the complex numbers with numeric constants,
   460 nonstandard complex numbers, and some complex analysis, standard and
   461 nonstandard (Jacques Fleuriot);
   462 
   463 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   464 
   465 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   466 Fleuriot);
   467 
   468 * Real/HahnBanach: updated and adapted to locales;
   469 
   470 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   471 Gray and Kramer);
   472 
   473 * UNITY: added the Meier-Sanders theory of progress sets;
   474 
   475 * MicroJava: bytecode verifier and lightweight bytecode verifier
   476 as abstract algorithms, instantiated to the JVM;
   477 
   478 * Bali: Java source language formalization. Type system, operational
   479 semantics, axiomatic semantics. Supported language features:
   480 classes, interfaces, objects,virtual methods, static methods,
   481 static/instance fields, arrays, access modifiers, definite
   482 assignment, exceptions.
   483 
   484 
   485 *** ZF ***
   486 
   487 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   488 universe, etc.);
   489 
   490 * Main ZF: virtually all theories converted to new-style format;
   491 
   492 
   493 *** ML ***
   494 
   495 * Pure: Tactic.prove provides sane interface for internal proofs;
   496 omits the infamous "standard" operation, so this is more appropriate
   497 than prove_goalw_cterm in many situations (e.g. in simprocs);
   498 
   499 * Pure: improved error reporting of simprocs;
   500 
   501 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   502 up simprocs;
   503 
   504 
   505 *** Document preparation ***
   506 
   507 * uses \par instead of \\ for line breaks in theory text. This may
   508 shift some page breaks in large documents. To get the old behaviour
   509 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   510 
   511 * minimized dependencies of isabelle.sty and isabellesym.sty on
   512 other packages
   513 
   514 * \<euro> now needs package babel/greek instead of marvosym (which
   515 broke \Rightarrow)
   516 
   517 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   518 textcomp package)
   519 
   520 
   521 
   522 New in Isabelle2002 (March 2002)
   523 --------------------------------
   524 
   525 *** Document preparation ***
   526 
   527 * greatly simplified document preparation setup, including more
   528 graceful interpretation of isatool usedir -i/-d/-D options, and more
   529 instructive isatool mkdir; users should basically be able to get
   530 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   531 users may run a separate document processing stage manually like this:
   532 "isatool usedir -D output HOL Test && isatool document Test/output";
   533 
   534 * theory dependency graph may now be incorporated into documents;
   535 isatool usedir -g true will produce session_graph.eps/.pdf for use
   536 with \includegraphics of LaTeX;
   537 
   538 * proper spacing of consecutive markup elements, especially text
   539 blocks after section headings;
   540 
   541 * support bold style (for single symbols only), input syntax is like
   542 this: "\<^bold>\<alpha>" or "\<^bold>A";
   543 
   544 * \<bullet> is now output as bold \cdot by default, which looks much
   545 better in printed text;
   546 
   547 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   548 note that these symbols are currently unavailable in Proof General /
   549 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   550 
   551 * isatool latex no longer depends on changed TEXINPUTS, instead
   552 isatool document copies the Isabelle style files to the target
   553 location;
   554 
   555 
   556 *** Isar ***
   557 
   558 * Pure/Provers: improved proof by cases and induction;
   559   - 'case' command admits impromptu naming of parameters (such as
   560     "case (Suc n)");
   561   - 'induct' method divinates rule instantiation from the inductive
   562     claim; no longer requires excessive ?P bindings for proper
   563     instantiation of cases;
   564   - 'induct' method properly enumerates all possibilities of set/type
   565     rules; as a consequence facts may be also passed through *type*
   566     rules without further ado;
   567   - 'induct' method now derives symbolic cases from the *rulified*
   568     rule (before it used to rulify cases stemming from the internal
   569     atomized version); this means that the context of a non-atomic
   570     statement becomes is included in the hypothesis, avoiding the
   571     slightly cumbersome show "PROP ?case" form;
   572   - 'induct' may now use elim-style induction rules without chaining
   573     facts, using ``missing'' premises from the goal state; this allows
   574     rules stemming from inductive sets to be applied in unstructured
   575     scripts, while still benefitting from proper handling of non-atomic
   576     statements; NB: major inductive premises need to be put first, all
   577     the rest of the goal is passed through the induction;
   578   - 'induct' proper support for mutual induction involving non-atomic
   579     rule statements (uses the new concept of simultaneous goals, see
   580     below);
   581   - append all possible rule selections, but only use the first
   582     success (no backtracking);
   583   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   584   - undeclared rule case names default to numbers 1, 2, 3, ...;
   585   - added 'print_induct_rules' (covered by help item in recent Proof
   586     General versions);
   587   - moved induct/cases attributes to Pure, methods to Provers;
   588   - generic method setup instantiated for FOL and HOL;
   589 
   590 * Pure: support multiple simultaneous goal statements, for example
   591 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   592 meta-level mechanism, this acts as if several individual goals had
   593 been stated separately; in particular common proof methods need to be
   594 repeated in order to cover all claims; note that a single elimination
   595 step is *not* sufficient to establish the two conjunctions, so this
   596 fails:
   597 
   598   assume "A & B" then have A and B ..   (*".." fails*)
   599 
   600 better use "obtain" in situations as above; alternative refer to
   601 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   602 
   603 * Pure: proper integration with ``locales''; unlike the original
   604 version by Florian Kammüller, Isar locales package high-level proof
   605 contexts rather than raw logical ones (e.g. we admit to include
   606 attributes everywhere); operations on locales include merge and
   607 rename; support for implicit arguments (``structures''); simultaneous
   608 type-inference over imports and text; see also HOL/ex/Locales.thy for
   609 some examples;
   610 
   611 * Pure: the following commands have been ``localized'', supporting a
   612 target locale specification "(in name)": 'lemma', 'theorem',
   613 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   614 stored both within the locale and at the theory level (exported and
   615 qualified by the locale name);
   616 
   617 * Pure: theory goals may now be specified in ``long'' form, with
   618 ad-hoc contexts consisting of arbitrary locale elements. for example
   619 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   620 definitions may be given, too); the result is a meta-level rule with
   621 the context elements being discharged in the obvious way;
   622 
   623 * Pure: new proof command 'using' allows to augment currently used
   624 facts after a goal statement ('using' is syntactically analogous to
   625 'apply', but acts on the goal's facts only); this allows chained facts
   626 to be separated into parts given before and after a claim, as in
   627 ``from a and b have C using d and e <proof>'';
   628 
   629 * Pure: renamed "antecedent" case to "rule_context";
   630 
   631 * Pure: new 'judgment' command records explicit information about the
   632 object-logic embedding (used by several tools internally); no longer
   633 use hard-wired "Trueprop";
   634 
   635 * Pure: added 'corollary' command;
   636 
   637 * Pure: fixed 'token_translation' command;
   638 
   639 * Pure: removed obsolete 'exported' attribute;
   640 
   641 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   642 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   643 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   644 
   645 * Pure: method 'atomize' presents local goal premises as object-level
   646 statements (atomic meta-level propositions); setup controlled via
   647 rewrite rules declarations of 'atomize' attribute; example
   648 application: 'induct' method with proper rule statements in improper
   649 proof *scripts*;
   650 
   651 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   652 now consider the syntactic context of assumptions, giving a better
   653 chance to get type-inference of the arguments right (this is
   654 especially important for locales);
   655 
   656 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   657 mode;
   658 
   659 * Pure/obtain: the formal conclusion "thesis", being marked as
   660 ``internal'', may no longer be reference directly in the text;
   661 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   662 situations;
   663 
   664 * Pure: generic 'sym' attribute which declares a rule both as pure
   665 'elim?' and for the 'symmetric' operation;
   666 
   667 * Pure: marginal comments ``--'' may now occur just anywhere in the
   668 text; the fixed correlation with particular command syntax has been
   669 discontinued;
   670 
   671 * Pure: new method 'rules' is particularly well-suited for proof
   672 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   673 but often produces more compact proof terms with less detours;
   674 
   675 * Pure/Provers/classical: simplified integration with pure rule
   676 attributes and methods; the classical "intro?/elim?/dest?"
   677 declarations coincide with the pure ones; the "rule" method no longer
   678 includes classically swapped intros; "intro" and "elim" methods no
   679 longer pick rules from the context; also got rid of ML declarations
   680 AddXIs/AddXEs/AddXDs; all of this has some potential for
   681 INCOMPATIBILITY;
   682 
   683 * Provers/classical: attribute 'swapped' produces classical inversions
   684 of introduction rules;
   685 
   686 * Provers/simplifier: 'simplified' attribute may refer to explicit
   687 rules instead of full simplifier context; 'iff' attribute handles
   688 conditional rules;
   689 
   690 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   691 
   692 * HOL: 'recdef' now fails on unfinished automated proofs, use
   693 "(permissive)" option to recover old behavior;
   694 
   695 * HOL: 'inductive' no longer features separate (collective) attributes
   696 for 'intros' (was found too confusing);
   697 
   698 * HOL: properly declared induction rules less_induct and
   699 wf_induct_rule;
   700 
   701 
   702 *** HOL ***
   703 
   704 * HOL: moved over to sane numeral syntax; the new policy is as
   705 follows:
   706 
   707   - 0 and 1 are polymorphic constants, which are defined on any
   708   numeric type (nat, int, real etc.);
   709 
   710   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   711   binary representation internally;
   712 
   713   - type nat has special constructor Suc, and generally prefers Suc 0
   714   over 1::nat and Suc (Suc 0) over 2::nat;
   715 
   716 This change may cause significant problems of INCOMPATIBILITY; here
   717 are some hints on converting existing sources:
   718 
   719   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   720   entities, so expressions involving "-" (unary or binary minus) need
   721   to be spaced properly;
   722 
   723   - existing occurrences of "1" may need to be constraint "1::nat" or
   724   even replaced by Suc 0; similar for old "2";
   725 
   726   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   727 
   728   - remove all special provisions on numerals in proofs;
   729 
   730 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   731 representation (depends on bin_arith_simps in the default context);
   732 
   733 * HOL: symbolic syntax for x^2 (numeral 2);
   734 
   735 * HOL: the class of all HOL types is now called "type" rather than
   736 "term"; INCOMPATIBILITY, need to adapt references to this type class
   737 in axclass/classes, instance/arities, and (usually rare) occurrences
   738 in typings (of consts etc.); internally the class is called
   739 "HOL.type", ML programs should refer to HOLogic.typeS;
   740 
   741 * HOL/record package improvements:
   742   - new derived operations "fields" to build a partial record section,
   743     "extend" to promote a fixed record to a record scheme, and
   744     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   745     declared as simp by default;
   746   - shared operations ("more", "fields", etc.) now need to be always
   747     qualified) --- potential INCOMPATIBILITY;
   748   - removed "make_scheme" operations (use "make" with "extend") --
   749     INCOMPATIBILITY;
   750   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   751   - provides cases/induct rules for use with corresponding Isar
   752     methods (for concrete records, record schemes, concrete more
   753     parts, and schematic more parts -- in that order);
   754   - internal definitions directly based on a light-weight abstract
   755     theory of product types over typedef rather than datatype;
   756 
   757 * HOL: generic code generator for generating executable ML code from
   758 specifications; specific support for HOL constructs such as inductive
   759 datatypes and sets, as well as recursive functions; can be invoked
   760 via 'generate_code' theory section;
   761 
   762 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   763 
   764 * HOL: consolidated and renamed several theories.  In particular:
   765         Ord.thy has been absorbed into HOL.thy
   766         String.thy has been absorbed into List.thy
   767 
   768 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   769 (beware of argument permutation!);
   770 
   771 * HOL: linorder_less_split superseded by linorder_cases;
   772 
   773 * HOL/List: "nodups" renamed to "distinct";
   774 
   775 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   776 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   777   - Ex_def has changed, now need to use some_eq_ex
   778 
   779 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   780 in this (rare) case use:
   781 
   782   delSWrapper "split_all_tac"
   783   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   784 
   785 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   786 MAY FAIL;
   787 
   788 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   789 Isabelle's type classes, ^ on functions and relations has too general
   790 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   791 necessary to attach explicit type constraints;
   792 
   793 * HOL/Relation: the prefix name of the infix "O" has been changed from
   794 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   795 renamed accordingly (eg "compI" -> "rel_compI").
   796 
   797 * HOL: syntax translations now work properly with numerals and records
   798 expressions;
   799 
   800 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   801 of "lam" -- INCOMPATIBILITY;
   802 
   803 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   804 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   805 renamed "Product_Type.unit";
   806 
   807 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   808 
   809 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   810 the "cases" method);
   811 
   812 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   813 Florian Kammüller);
   814 
   815 * HOL/IMP: updated and converted to new-style theory format; several
   816 parts turned into readable document, with proper Isar proof texts and
   817 some explanations (by Gerwin Klein);
   818 
   819 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   820 
   821 * HOL-Hyperreal is now a logic image;
   822 
   823 
   824 *** HOLCF ***
   825 
   826 * Isar: consts/constdefs supports mixfix syntax for continuous
   827 operations;
   828 
   829 * Isar: domain package adapted to new-style theory format, e.g. see
   830 HOLCF/ex/Dnat.thy;
   831 
   832 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   833 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   834 lift.induct_tac, always use UU instead of Undef;
   835 
   836 * HOLCF/IMP: updated and converted to new-style theory;
   837 
   838 
   839 *** ZF ***
   840 
   841 * Isar: proper integration of logic-specific tools and packages,
   842 including theory commands '(co)inductive', '(co)datatype',
   843 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   844 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   845 
   846 * theory Main no longer includes AC; for the Axiom of Choice, base
   847 your theory on Main_ZFC;
   848 
   849 * the integer library now covers quotients and remainders, with many
   850 laws relating division to addition, multiplication, etc.;
   851 
   852 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   853 typeless version of the formalism;
   854 
   855 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   856 format;
   857 
   858 * ZF/Induct: new directory for examples of inductive definitions,
   859 including theory Multiset for multiset orderings; converted to
   860 new-style theory format;
   861 
   862 * ZF: many new theorems about lists, ordinals, etc.;
   863 
   864 
   865 *** General ***
   866 
   867 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   868 variable proof controls level of detail: 0 = no proofs (only oracle
   869 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   870 also ref manual for further ML interfaces;
   871 
   872 * Pure/axclass: removed obsolete ML interface
   873 goal_subclass/goal_arity;
   874 
   875 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   876 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   877 separate tokens, so expressions involving minus need to be spaced
   878 properly;
   879 
   880 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   881 rather than "infixl" or "infixr";
   882 
   883 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   884 sort constraint specifications in type inference; e.g. "x::_::foo"
   885 ensures that the type of "x" is of sort "foo" (but not necessarily a
   886 type variable);
   887 
   888 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   889 control output of nested => (types); the default behavior is
   890 "type_brackets";
   891 
   892 * Pure/syntax: builtin parse translation for "_constify" turns valued
   893 tokens into AST constants;
   894 
   895 * Pure/syntax: prefer later declarations of translations and print
   896 translation functions; potential INCOMPATIBILITY: need to reverse
   897 multiple declarations for same syntax element constant;
   898 
   899 * Pure/show_hyps reset by default (in accordance to existing Isar
   900 practice);
   901 
   902 * Provers/classical: renamed addaltern to addafter, addSaltern to
   903 addSafter;
   904 
   905 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   906 as well;
   907 
   908 * system: tested support for MacOS X; should be able to get Isabelle +
   909 Proof General to work in a plain Terminal after installing Poly/ML
   910 (e.g. from the Isabelle distribution area) and GNU bash alone
   911 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   912 support requires further installations, e.g. from
   913 http://fink.sourceforge.net/);
   914 
   915 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   916 
   917 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   918 of 40 MB), cf. ML_OPTIONS;
   919 
   920 * system: Proof General keywords specification is now part of the
   921 Isabelle distribution (see etc/isar-keywords.el);
   922 
   923 * system: support for persistent Proof General sessions (refrain from
   924 outdating all loaded theories on startup); user may create writable
   925 logic images like this: ``isabelle -q HOL Test'';
   926 
   927 * system: smart selection of Isabelle process versus Isabelle
   928 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   929 run both "isabelle" and "Isabelle" even if file names are badly
   930 damaged (executable inspects the case of the first letter of its own
   931 name); added separate "isabelle-process" and "isabelle-interface";
   932 
   933 * system: refrain from any attempt at filtering input streams; no
   934 longer support ``8bit'' encoding of old isabelle font, instead proper
   935 iso-latin characters may now be used; the related isatools
   936 "symbolinput" and "nonascii" have disappeared as well;
   937 
   938 * system: removed old "xterm" interface (the print modes "xterm" and
   939 "xterm_color" are still available for direct use in a suitable
   940 terminal);
   941 
   942 
   943 
   944 New in Isabelle99-2 (February 2001)
   945 -----------------------------------
   946 
   947 *** Overview of INCOMPATIBILITIES ***
   948 
   949 * HOL: please note that theories in the Library and elsewhere often use the
   950 new-style (Isar) format; to refer to their theorems in an ML script you must
   951 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   952 
   953 * HOL: inductive package no longer splits induction rule aggressively,
   954 but only as far as specified by the introductions given; the old
   955 format may be recovered via ML function complete_split_rule or attribute
   956 'split_rule (complete)';
   957 
   958 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   959 gfp_Tarski to gfp_unfold;
   960 
   961 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   962 
   963 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   964 relation); infix "^^" has been renamed "``"; infix "``" has been
   965 renamed "`"; "univalent" has been renamed "single_valued";
   966 
   967 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   968 operation;
   969 
   970 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   971 
   972 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   973 
   974 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   975 consequence, it is no longer monotonic wrt. the local goal context
   976 (which is now passed through the inductive cases);
   977 
   978 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   979 \<gg> to \<ggreater>;
   980 
   981 
   982 *** Document preparation ***
   983 
   984 * \isabellestyle{NAME} selects version of Isabelle output (currently
   985 available: are "it" for near math-mode best-style output, "sl" for
   986 slanted text style, and "tt" for plain type-writer; if no
   987 \isabellestyle command is given, output is according to slanted
   988 type-writer);
   989 
   990 * support sub/super scripts (for single symbols only), input syntax is
   991 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   992 
   993 * some more standard symbols; see Appendix A of the system manual for
   994 the complete list of symbols defined in isabellesym.sty;
   995 
   996 * improved isabelle style files; more abstract symbol implementation
   997 (should now use \isamath{...} and \isatext{...} in custom symbol
   998 definitions);
   999 
  1000 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1001 state; Note that presentation of goal states does not conform to
  1002 actual human-readable proof documents.  Please do not include goal
  1003 states into document output unless you really know what you are doing!
  1004 
  1005 * proper indentation of antiquoted output with proportional LaTeX
  1006 fonts;
  1007 
  1008 * no_document ML operator temporarily disables LaTeX document
  1009 generation;
  1010 
  1011 * isatool unsymbolize tunes sources for plain ASCII communication;
  1012 
  1013 
  1014 *** Isar ***
  1015 
  1016 * Pure: Isar now suffers initial goal statements to contain unbound
  1017 schematic variables (this does not conform to actual readable proof
  1018 documents, due to unpredictable outcome and non-compositional proof
  1019 checking); users who know what they are doing may use schematic goals
  1020 for Prolog-style synthesis of proven results;
  1021 
  1022 * Pure: assumption method (an implicit finishing) now handles actual
  1023 rules as well;
  1024 
  1025 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1026 initial goal, declare "that" only as Pure intro (only for single
  1027 steps); the "that" rule assumption may now be involved in implicit
  1028 finishing, thus ".." becomes a feasible for trivial obtains;
  1029 
  1030 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1031 instance proofs may be performed by "..";
  1032 
  1033 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1034 statements as well;
  1035 
  1036 * Pure: more robust selection of calculational rules;
  1037 
  1038 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1039 rule (as well as the assumption rule);
  1040 
  1041 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1042 lemmas, using the graph browser tool;
  1043 
  1044 * Pure: predict failure of "show" in interactive mode;
  1045 
  1046 * Pure: 'thms_containing' now takes actual terms as arguments;
  1047 
  1048 * HOL: improved method 'induct' --- now handles non-atomic goals
  1049 (potential INCOMPATIBILITY); tuned error handling;
  1050 
  1051 * HOL: cases and induct rules now provide explicit hints about the
  1052 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1053 any remaining facts are inserted into the goal verbatim;
  1054 
  1055 * HOL: local contexts (aka cases) may now contain term bindings as
  1056 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1057 the result to be shown in each case;
  1058 
  1059 * HOL: added 'recdef_tc' command;
  1060 
  1061 * isatool convert assists in eliminating legacy ML scripts;
  1062 
  1063 
  1064 *** HOL ***
  1065 
  1066 * HOL/Library: a collection of generic theories to be used together
  1067 with main HOL; the theory loader path already includes this directory
  1068 by default; the following existing theories have been moved here:
  1069 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1070 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1071 
  1072 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1073 modelling and verification task performed in Isabelle/HOL +
  1074 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1075 
  1076 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1077 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1078 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1079 'domain', this makes the theory consistent with mathematical
  1080 literature;
  1081 
  1082 * HOL basics: added overloaded operations "inverse" and "divide"
  1083 (infix "/"), syntax for generic "abs" operation, generic summation
  1084 operator \<Sum>;
  1085 
  1086 * HOL/typedef: simplified package, provide more useful rules (see also
  1087 HOL/subset.thy);
  1088 
  1089 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1090 now expressed as a proper nested rule (old-style tactic scripts may
  1091 require atomize_strip_tac to cope with non-atomic premises);
  1092 
  1093 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1094 to "split_conv" (old name still available for compatibility);
  1095 
  1096 * HOL: improved concrete syntax for strings (e.g. allows translation
  1097 rules with string literals);
  1098 
  1099 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1100  and Fleuriot's mechanization of analysis, including the transcendental
  1101  functions for the reals;
  1102 
  1103 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1104 
  1105 
  1106 *** CTT ***
  1107 
  1108 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1109 "lam" is displayed as TWO lambda-symbols
  1110 
  1111 * CTT: theory Main now available, containing everything (that is, Bool
  1112 and Arith);
  1113 
  1114 
  1115 *** General ***
  1116 
  1117 * Pure: the Simplifier has been implemented properly as a derived rule
  1118 outside of the actual kernel (at last!); the overall performance
  1119 penalty in practical applications is about 50%, while reliability of
  1120 the Isabelle inference kernel has been greatly improved;
  1121 
  1122 * print modes "brackets" and "no_brackets" control output of nested =>
  1123 (types) and ==> (props); the default behaviour is "brackets";
  1124 
  1125 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1126 as assumptions as well;
  1127 
  1128 * system: support Poly/ML 4.0;
  1129 
  1130 * system: isatool install handles KDE version 1 or 2;
  1131 
  1132 
  1133 
  1134 New in Isabelle99-1 (October 2000)
  1135 ----------------------------------
  1136 
  1137 *** Overview of INCOMPATIBILITIES ***
  1138 
  1139 * HOL: simplification of natural numbers is much changed; to partly
  1140 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1141 issue the following ML commands:
  1142 
  1143   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1144   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1145 
  1146 * HOL: simplification no longer dives into case-expressions; this is
  1147 controlled by "t.weak_case_cong" for each datatype t;
  1148 
  1149 * HOL: nat_less_induct renamed to less_induct;
  1150 
  1151 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1152 fixsome to patch .thy and .ML sources automatically;
  1153 
  1154   select_equality  -> some_equality
  1155   select_eq_Ex     -> some_eq_ex
  1156   selectI2EX       -> someI2_ex
  1157   selectI2         -> someI2
  1158   selectI          -> someI
  1159   select1_equality -> some1_equality
  1160   Eps_sym_eq       -> some_sym_eq_trivial
  1161   Eps_eq           -> some_eq_trivial
  1162 
  1163 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1164 
  1165 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1166 instead);
  1167 
  1168 * HOL: the recursion equations generated by 'recdef' are now called
  1169 f.simps instead of f.rules;
  1170 
  1171 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1172 
  1173 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1174 sometimes be needed;
  1175 
  1176 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1177 
  1178 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1179 
  1180 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1181 product is now "<*>" instead of "Times"; the lexicographic product is
  1182 now "<*lex*>" instead of "**";
  1183 
  1184 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1185 of main HOL, but was unused); better use HOL's datatype package;
  1186 
  1187 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1188 the old syntax may be recovered as follows:
  1189 
  1190   syntax (symbols)
  1191     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1192       (infixl "\\<oplus>" 100)
  1193 
  1194 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1195 
  1196 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1197 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1198 internally;
  1199 
  1200 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1201 changed from A/r to A//r;
  1202 
  1203 * ZF: new treatment of arithmetic (nat & int) may break some old
  1204 proofs;
  1205 
  1206 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1207 rulify -> rule_format, elimify -> elim_format, ...);
  1208 
  1209 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1210 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1211 should have to change intro!! to intro? only); replaced "delrule" by
  1212 "rule del";
  1213 
  1214 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1215 
  1216 * Provers: strengthened force_tac by using new first_best_tac;
  1217 
  1218 * LaTeX document preparation: several changes of isabelle.sty (see
  1219 lib/texinputs);
  1220 
  1221 
  1222 *** Document preparation ***
  1223 
  1224 * formal comments (text blocks etc.) in new-style theories may now
  1225 contain antiquotations of thm/prop/term/typ/text to be presented
  1226 according to latex print mode; concrete syntax is like this:
  1227 @{term[show_types] "f(x) = a + x"};
  1228 
  1229 * isatool mkdir provides easy setup of Isabelle session directories,
  1230 including proper document sources;
  1231 
  1232 * generated LaTeX sources are now deleted after successful run
  1233 (isatool document -c); may retain a copy somewhere else via -D option
  1234 of isatool usedir;
  1235 
  1236 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1237 style files, achieving self-contained LaTeX sources and simplifying
  1238 LaTeX debugging;
  1239 
  1240 * old-style theories now produce (crude) LaTeX output as well;
  1241 
  1242 * browser info session directories are now self-contained (may be put
  1243 on WWW server seperately); improved graphs of nested sessions; removed
  1244 graph for 'all sessions';
  1245 
  1246 * several improvements in isabelle style files; \isabellestyle{it}
  1247 produces fake math mode output; \isamarkupheader is now \section by
  1248 default; see lib/texinputs/isabelle.sty etc.;
  1249 
  1250 
  1251 *** Isar ***
  1252 
  1253 * Isar/Pure: local results and corresponding term bindings are now
  1254 subject to Hindley-Milner polymorphism (similar to ML); this
  1255 accommodates incremental type-inference very nicely;
  1256 
  1257 * Isar/Pure: new derived language element 'obtain' supports
  1258 generalized existence reasoning;
  1259 
  1260 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1261 support accumulation of results, without applying any rules yet;
  1262 useful to collect intermediate results without explicit name
  1263 references, and for use with transitivity rules with more than 2
  1264 premises;
  1265 
  1266 * Isar/Pure: scalable support for case-analysis type proofs: new
  1267 'case' language element refers to local contexts symbolically, as
  1268 produced by certain proof methods; internally, case names are attached
  1269 to theorems as "tags";
  1270 
  1271 * Isar/Pure: theory command 'hide' removes declarations from
  1272 class/type/const name spaces;
  1273 
  1274 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1275 indicate potential overloading;
  1276 
  1277 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1278 
  1279 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1280 "{a,b,c}" instead of {a,b,c};
  1281 
  1282 * Isar/Pure now provides its own version of intro/elim/dest
  1283 attributes; useful for building new logics, but beware of confusion
  1284 with the version in Provers/classical;
  1285 
  1286 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1287 case name 'antecedent';
  1288 
  1289 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1290 to the current context is now done automatically);
  1291 
  1292 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1293 for definining proof methods in ML;
  1294 
  1295 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1296 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1297 most cases, one should have to change intro!! to intro? only);
  1298 replaced "delrule" by "rule del";
  1299 
  1300 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1301 'symmetric' attribute (the latter supercedes [RS sym]);
  1302 
  1303 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1304 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1305 well (including splits);
  1306 
  1307 * Isar/Provers: Simplifier and Classical methods now support all kind
  1308 of modifiers used in the past, including 'cong', 'iff', etc.
  1309 
  1310 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1311 of Simplifier and Classical reasoner);
  1312 
  1313 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1314 now support named cases; major packages (inductive, datatype, primrec,
  1315 recdef) support case names and properly name parameters;
  1316 
  1317 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1318 monotonicity conditions are extracted to be proven at end of
  1319 calculations;
  1320 
  1321 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1322 method anyway;
  1323 
  1324 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1325 split_if split_if_asm; datatype package provides theorems foo.splits =
  1326 foo.split foo.split_asm for each datatype;
  1327 
  1328 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1329 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1330 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1331 use "(cases (simplified))" method in proper proof texts);
  1332 
  1333 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1334 
  1335 * Isar: names of theorems etc. may be natural numbers as well;
  1336 
  1337 * Isar: 'pr' command: optional arguments for goals_limit and
  1338 ProofContext.prems_limit; no longer prints theory contexts, but only
  1339 proof states;
  1340 
  1341 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1342 additional print modes to be specified; e.g. "pr(latex)" will print
  1343 proof state according to the Isabelle LaTeX style;
  1344 
  1345 * Isar: improved support for emulating tactic scripts, including proof
  1346 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1347 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1348 (for HOL datatypes);
  1349 
  1350 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1351 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1352 'proof method scripts' have to be in depth-first order;
  1353 
  1354 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1355 
  1356 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1357 should instead use individual commands for printing items
  1358 (print_commands, print_methods etc.);
  1359 
  1360 * Isar: added 'nothing' --- the empty list of theorems;
  1361 
  1362 
  1363 *** HOL ***
  1364 
  1365 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1366 corresponding virtual machine and a specification of its bytecode
  1367 verifier and a lightweight bytecode verifier, including proofs of
  1368 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1369 Cornelia Pusch (see also the homepage of project Bali at
  1370 http://isabelle.in.tum.de/Bali/);
  1371 
  1372 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1373 Clemens Ballarin;
  1374 
  1375 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1376 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1377 Rasmussen;
  1378 
  1379 * HOL/Lattice: fundamental concepts of lattice theory and order
  1380 structures, including duals, properties of bounds versus algebraic
  1381 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1382 Theorem for complete lattices etc.; may also serve as a demonstration
  1383 for abstract algebraic reasoning using axiomatic type classes, and
  1384 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1385 
  1386 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1387 von Oheimb;
  1388 
  1389 * HOL/IMPP: extension of IMP with local variables and mutually
  1390 recursive procedures, by David von Oheimb;
  1391 
  1392 * HOL/Lambda: converted into new-style theory and document;
  1393 
  1394 * HOL/ex/Multiquote: example of multiple nested quotations and
  1395 anti-quotations -- basically a generalized version of de-Bruijn
  1396 representation; very useful in avoiding lifting of operations;
  1397 
  1398 * HOL/record: added general record equality rule to simpset; fixed
  1399 select-update simplification procedure to handle extended records as
  1400 well; admit "r" as field name;
  1401 
  1402 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1403 other numeric types and also as the identity of groups, rings, etc.;
  1404 
  1405 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1406 Types nat and int belong to this axclass;
  1407 
  1408 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1409    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1410    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1411   two terms #m*u and #n*u are replaced by #(m+n)*u
  1412     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1413   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1414     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1415 
  1416 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1417 powerful prover for predicate logic but knows nothing of clasets; see
  1418 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1419 
  1420 * HOL: new version of "case_tac" subsumes both boolean case split and
  1421 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1422 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1423 
  1424 * HOL: simplification no longer dives into case-expressions: only the
  1425 selector expression is simplified, but not the remaining arms; to
  1426 enable full simplification of case-expressions for datatype t, you may
  1427 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1428 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1429 
  1430 * HOL/recdef: the recursion equations generated by 'recdef' for
  1431 function 'f' are now called f.simps instead of f.rules; if all
  1432 termination conditions are proved automatically, these simplification
  1433 rules are added to the simpset, as in primrec; rules may be named
  1434 individually as well, resulting in a separate list of theorems for
  1435 each equation;
  1436 
  1437 * HOL/While is a new theory that provides a while-combinator. It
  1438 permits the definition of tail-recursive functions without the
  1439 provision of a termination measure. The latter is necessary once the
  1440 invariant proof rule for while is applied.
  1441 
  1442 * HOL: new (overloaded) notation for the set of elements below/above
  1443 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1444 
  1445 * HOL: theorems impI, allI, ballI bound as "strip";
  1446 
  1447 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1448 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1449 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1450 
  1451 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1452 
  1453 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1454 main HOL, but was unused);
  1455 
  1456 * HOL: fewer consts declared as global (e.g. have to refer to
  1457 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1458 
  1459 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1460 in case of overlap with user translations (e.g. judgements over
  1461 tuples); (note that the underlying logical represenation is still
  1462 bogus);
  1463 
  1464 
  1465 *** ZF ***
  1466 
  1467 * ZF: simplification automatically cancels common terms in arithmetic
  1468 expressions over nat and int;
  1469 
  1470 * ZF: new treatment of nat to minimize type-checking: all operators
  1471 coerce their operands to a natural number using the function natify,
  1472 making the algebraic laws unconditional;
  1473 
  1474 * ZF: as above, for int: operators coerce their operands to an integer
  1475 using the function intify;
  1476 
  1477 * ZF: the integer library now contains many of the usual laws for the
  1478 orderings, including $<=, and monotonicity laws for $+ and $*;
  1479 
  1480 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1481 simplification;
  1482 
  1483 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1484 to the simplifier and classical reasoner simultaneously;
  1485 
  1486 
  1487 *** General ***
  1488 
  1489 * Provers: blast_tac now handles actual object-logic rules as
  1490 assumptions; note that auto_tac uses blast_tac internally as well;
  1491 
  1492 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1493 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1494 
  1495 * Provers: delrules now handles destruct rules as well (no longer need
  1496 explicit make_elim);
  1497 
  1498 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1499   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1500 use instead the strong form,
  1501   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1502 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1503 from destruct-rules;
  1504 
  1505 * Provers: Simplifier.easy_setup provides a fast path to basic
  1506 Simplifier setup for new object-logics;
  1507 
  1508 * Pure: AST translation rules no longer require constant head on LHS;
  1509 
  1510 * Pure: improved name spaces: ambiguous output is qualified; support
  1511 for hiding of names;
  1512 
  1513 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1514 XSYMBOL_HOME; no longer need to do manual configuration in most
  1515 situations;
  1516 
  1517 * system: compression of ML heaps images may now be controlled via -c
  1518 option of isabelle and isatool usedir (currently only observed by
  1519 Poly/ML);
  1520 
  1521 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1522 useful for remote X11);
  1523 
  1524 * system: provide TAGS file for Isabelle sources;
  1525 
  1526 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1527 order;
  1528 
  1529 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1530 timing flag supersedes proof_timing and Toplevel.trace;
  1531 
  1532 * ML: new combinators |>> and |>>> for incremental transformations
  1533 with secondary results (e.g. certain theory extensions):
  1534 
  1535 * ML: PureThy.add_defs gets additional argument to indicate potential
  1536 overloading (usually false);
  1537 
  1538 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1539 results;
  1540 
  1541 
  1542 
  1543 New in Isabelle99 (October 1999)
  1544 --------------------------------
  1545 
  1546 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1547 
  1548 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1549 are no longer simplified.  (This allows the simplifier to unfold recursive
  1550 functional programs.)  To restore the old behaviour, declare
  1551 
  1552     Delcongs [if_weak_cong];
  1553 
  1554 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1555 complement;
  1556 
  1557 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1558 
  1559 * HOL/datatype: mutual_induct_tac no longer exists --
  1560   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1561 
  1562 * HOL/typedef: fixed type inference for representing set; type
  1563 arguments now have to occur explicitly on the rhs as type constraints;
  1564 
  1565 * ZF: The con_defs part of an inductive definition may no longer refer
  1566 to constants declared in the same theory;
  1567 
  1568 * HOL, ZF: the function mk_cases, generated by the inductive
  1569 definition package, has lost an argument.  To simplify its result, it
  1570 uses the default simpset instead of a supplied list of theorems.
  1571 
  1572 * HOL/List: the constructors of type list are now Nil and Cons;
  1573 
  1574 * Simplifier: the type of the infix ML functions
  1575         setSSolver addSSolver setSolver addSolver
  1576 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1577 for packaging solvers. A solver is created via
  1578         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1579 where the string argument is only a comment.
  1580 
  1581 
  1582 *** Proof tools ***
  1583 
  1584 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1585 decision procedure for linear arithmetic. Currently it is used for
  1586 types `nat', `int', and `real' in HOL (see below); it can, should and
  1587 will be instantiated for other types and logics as well.
  1588 
  1589 * The simplifier now accepts rewrite rules with flexible heads, eg
  1590      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1591   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1592   matching.
  1593 
  1594 
  1595 *** General ***
  1596 
  1597 * New Isabelle/Isar subsystem provides an alternative to traditional
  1598 tactical theorem proving; together with the ProofGeneral/isar user
  1599 interface it offers an interactive environment for developing human
  1600 readable proof documents (Isar == Intelligible semi-automated
  1601 reasoning); for further information see isatool doc isar-ref,
  1602 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1603 
  1604 * improved and simplified presentation of theories: better HTML markup
  1605 (including colors), graph views in several sizes; isatool usedir now
  1606 provides a proper interface for user theories (via -P option); actual
  1607 document preparation based on (PDF)LaTeX is available as well (for
  1608 new-style theories only); see isatool doc system for more information;
  1609 
  1610 * native support for Proof General, both for classic Isabelle and
  1611 Isabelle/Isar;
  1612 
  1613 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1614 using the graph browser tool;
  1615 
  1616 * Isabelle manuals now also available as PDF;
  1617 
  1618 * theory loader rewritten from scratch (may not be fully
  1619 bug-compatible); old loadpath variable has been replaced by show_path,
  1620 add_path, del_path, reset_path functions; new operations such as
  1621 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1622 isatool doc ref);
  1623 
  1624 * improved isatool install: option -k creates KDE application icon,
  1625 option -p DIR installs standalone binaries;
  1626 
  1627 * added ML_PLATFORM setting (useful for cross-platform installations);
  1628 more robust handling of platform specific ML images for SML/NJ;
  1629 
  1630 * the settings environment is now statically scoped, i.e. it is never
  1631 created again in sub-processes invoked from isabelle, isatool, or
  1632 Isabelle;
  1633 
  1634 * path element specification '~~' refers to '$ISABELLE_HOME';
  1635 
  1636 * in locales, the "assumes" and "defines" parts may be omitted if
  1637 empty;
  1638 
  1639 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1640 long arrows);
  1641 
  1642 * new print_mode "HTML";
  1643 
  1644 * new flag show_tags controls display of tags of theorems (which are
  1645 basically just comments that may be attached by some tools);
  1646 
  1647 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1648 mode and goal output format:
  1649 
  1650 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1651 244c244
  1652 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1653 ---
  1654 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1655 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1656 181c181
  1657 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1658 ---
  1659 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1660 
  1661 * function bind_thms stores lists of theorems (cf. bind_thm);
  1662 
  1663 * new shorthand tactics ftac, eatac, datac, fatac;
  1664 
  1665 * qed (and friends) now accept "" as result name; in that case the
  1666 theorem is not stored, but proper checks and presentation of the
  1667 result still apply;
  1668 
  1669 * theorem database now also indexes constants "Trueprop", "all",
  1670 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1671 
  1672 
  1673 *** HOL ***
  1674 
  1675 ** HOL arithmetic **
  1676 
  1677 * There are now decision procedures for linear arithmetic over nat and
  1678 int:
  1679 
  1680 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1681 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1682 are treated as atomic; subformulae not involving type `nat' or `int'
  1683 are ignored; quantified subformulae are ignored unless they are
  1684 positive universal or negative existential. The tactic has to be
  1685 invoked by hand and can be a little bit slow. In particular, the
  1686 running time is exponential in the number of occurrences of `min' and
  1687 `max', and `-' on `nat'.
  1688 
  1689 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1690 (negated) (in)equalities among the premises and the conclusion into
  1691 account (i.e. no compound formulae) and does not know about `min' and
  1692 `max', and `-' on `nat'. It is fast and is used automatically by the
  1693 simplifier.
  1694 
  1695 NB: At the moment, these decision procedures do not cope with mixed
  1696 nat/int formulae where the two parts interact, such as `m < n ==>
  1697 int(m) < int(n)'.
  1698 
  1699 * HOL/Numeral provides a generic theory of numerals (encoded
  1700 efficiently as bit strings); setup for types nat/int/real is in place;
  1701 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1702 int, existing theories and proof scripts may require a few additional
  1703 type constraints;
  1704 
  1705 * integer division and remainder can now be performed on constant
  1706 arguments;
  1707 
  1708 * many properties of integer multiplication, division and remainder
  1709 are now available;
  1710 
  1711 * An interface to the Stanford Validity Checker (SVC) is available through the
  1712 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1713 are proved automatically.  SVC must be installed separately, and its results
  1714 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1715 invocation of the underlying oracle).  For SVC see
  1716   http://verify.stanford.edu/SVC
  1717 
  1718 * IsaMakefile: the HOL-Real target now builds an actual image;
  1719 
  1720 
  1721 ** HOL misc **
  1722 
  1723 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1724 (in Isabelle/Isar) -- by Gertrud Bauer;
  1725 
  1726 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1727 analysis for assembly languages with subtypes;
  1728 
  1729 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1730 -- avoids syntactic ambiguities and treats state, transition, and
  1731 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1732 changed syntax and (many) tactics;
  1733 
  1734 * HOL/inductive: Now also handles more general introduction rules such
  1735   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1736   theorems are now maintained within the theory (maintained via the
  1737   "mono" attribute);
  1738 
  1739 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1740   (using function types) such as
  1741 
  1742   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1743 
  1744 * HOL/record: record_simproc (part of the default simpset) takes care
  1745 of selectors applied to updated records; record_split_tac is no longer
  1746 part of the default claset; update_defs may now be removed from the
  1747 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1748 
  1749   claset_ref () := claset() addSWrapper record_split_wrapper;
  1750   Delsimprocs [record_simproc]
  1751 
  1752 * HOL/typedef: fixed type inference for representing set; type
  1753 arguments now have to occur explicitly on the rhs as type constraints;
  1754 
  1755 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1756 names rather than an ML expression;
  1757 
  1758 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1759 supplied later.  Program schemes can be defined, such as
  1760     "While B C s = (if B s then While B C (C s) else s)"
  1761 where the well-founded relation can be chosen after B and C have been given.
  1762 
  1763 * HOL/List: the constructors of type list are now Nil and Cons;
  1764 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1765 course, ML tools referring to List.list.op # etc. have to be adapted;
  1766 
  1767 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1768 disabled by default; run isabelle with option -m HOL to get back to
  1769 the original Gordon/HOL-style output;
  1770 
  1771 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1772 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1773 
  1774 * HOL basic syntax simplified (more orthogonal): all variants of
  1775 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1776 Eps operator is provided as well: "SOME x. P[x]";
  1777 
  1778 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1779 
  1780 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1781 thus available for user theories;
  1782 
  1783 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1784 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1785 time;
  1786 
  1787 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1788 several times and then mp;
  1789 
  1790 
  1791 *** LK ***
  1792 
  1793 * the notation <<...>> is now available as a notation for sequences of
  1794 formulas;
  1795 
  1796 * the simplifier is now installed
  1797 
  1798 * the axiom system has been generalized (thanks to Soren Heilmann)
  1799 
  1800 * the classical reasoner now has a default rule database
  1801 
  1802 
  1803 *** ZF ***
  1804 
  1805 * new primrec section allows primitive recursive functions to be given
  1806 directly (as in HOL) over datatypes and the natural numbers;
  1807 
  1808 * new tactics induct_tac and exhaust_tac for induction (or case
  1809 analysis) over datatypes and the natural numbers;
  1810 
  1811 * the datatype declaration of type T now defines the recursor T_rec;
  1812 
  1813 * simplification automatically does freeness reasoning for datatype
  1814 constructors;
  1815 
  1816 * automatic type-inference, with AddTCs command to insert new
  1817 type-checking rules;
  1818 
  1819 * datatype introduction rules are now added as Safe Introduction rules
  1820 to the claset;
  1821 
  1822 * the syntax "if P then x else y" is now available in addition to
  1823 if(P,x,y);
  1824 
  1825 
  1826 *** Internal programming interfaces ***
  1827 
  1828 * tuned simplifier trace output; new flag debug_simp;
  1829 
  1830 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1831 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1832 
  1833 * AxClass.axclass_tac lost the theory argument;
  1834 
  1835 * tuned current_goals_markers semantics: begin / end goal avoids
  1836 printing empty lines;
  1837 
  1838 * removed prs and prs_fn hook, which was broken because it did not
  1839 include \n in its semantics, forcing writeln to add one
  1840 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1841 string -> unit if you really want to output text without newline;
  1842 
  1843 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1844 plain output, interface builders may have to enable 'isabelle_font'
  1845 mode to get Isabelle font glyphs as before;
  1846 
  1847 * refined token_translation interface; INCOMPATIBILITY: output length
  1848 now of type real instead of int;
  1849 
  1850 * theory loader actions may be traced via new ThyInfo.add_hook
  1851 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1852 your own database of information attached to *whole* theories -- as
  1853 opposed to intra-theory data slots offered via TheoryDataFun;
  1854 
  1855 * proper handling of dangling sort hypotheses (at last!);
  1856 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1857 extra sort hypotheses that can be witnessed from the type signature;
  1858 the force_strip_shyps flag is gone, any remaining shyps are simply
  1859 left in the theorem (with a warning issued by strip_shyps_warning);
  1860 
  1861 
  1862 
  1863 New in Isabelle98-1 (October 1998)
  1864 ----------------------------------
  1865 
  1866 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1867 
  1868 * several changes of automated proof tools;
  1869 
  1870 * HOL: major changes to the inductive and datatype packages, including
  1871 some minor incompatibilities of theory syntax;
  1872 
  1873 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1874 called `inj_on';
  1875 
  1876 * HOL: removed duplicate thms in Arith:
  1877   less_imp_add_less  should be replaced by  trans_less_add1
  1878   le_imp_add_le      should be replaced by  trans_le_add1
  1879 
  1880 * HOL: unary minus is now overloaded (new type constraints may be
  1881 required);
  1882 
  1883 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1884 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1885 now taken as an integer constant.
  1886 
  1887 * Pure: ML function 'theory_of' renamed to 'theory';
  1888 
  1889 
  1890 *** Proof tools ***
  1891 
  1892 * Simplifier:
  1893   1. Asm_full_simp_tac is now more aggressive.
  1894      1. It will sometimes reorient premises if that increases their power to
  1895         simplify.
  1896      2. It does no longer proceed strictly from left to right but may also
  1897         rotate premises to achieve further simplification.
  1898      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1899      old Asm_full_simp_tac in that it does not rotate premises.
  1900   2. The simplifier now knows a little bit about nat-arithmetic.
  1901 
  1902 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1903 allows for selected deletion of wrappers, by introduction of names for
  1904 wrapper functionals.  This implies that addbefore, addSbefore,
  1905 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1906 and that adding two tactics with the same name overwrites the first
  1907 one (emitting a warning).
  1908   type wrapper = (int -> tactic) -> (int -> tactic)
  1909   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1910   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1911   delWrapper, delSWrapper: claset *  string            -> claset
  1912   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1913 
  1914 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1915 semantics; addbefore now affects only the unsafe part of step_tac
  1916 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1917 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1918 by Force_tac;
  1919 
  1920 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1921 compWrapper; added safe wrapper (and access functions for it);
  1922 
  1923 * HOL/split_all_tac is now much faster and fails if there is nothing
  1924 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1925 and the names of the automatically generated variables have changed.
  1926 split_all_tac has moved within claset() from unsafe wrappers to safe
  1927 wrappers, which means that !!-bound variables are split much more
  1928 aggressively, and safe_tac and clarify_tac now split such variables.
  1929 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1930 Note: the same holds for record_split_tac, which does the job of
  1931 split_all_tac for record fields.
  1932 
  1933 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1934 permanently to the default simpset using Addsplits just like
  1935 Addsimps. They can be removed via Delsplits just like
  1936 Delsimps. Lower-case versions are also available.
  1937 
  1938 * HOL/Simplifier: The rule split_if is now part of the default
  1939 simpset. This means that the simplifier will eliminate all occurrences
  1940 of if-then-else in the conclusion of a goal. To prevent this, you can
  1941 either remove split_if completely from the default simpset by
  1942 `Delsplits [split_if]' or remove it in a specific call of the
  1943 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1944 other case splitting rules to/from the default simpset: every datatype
  1945 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1946 t is the name of the datatype).
  1947 
  1948 * Classical reasoner / Simplifier combination: new force_tac (and
  1949 derivatives Force_tac, force) combines rewriting and classical
  1950 reasoning (and whatever other tools) similarly to auto_tac, but is
  1951 aimed to solve the given subgoal completely.
  1952 
  1953 
  1954 *** General ***
  1955 
  1956 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1957 and `goalw': the theory is no longer needed as an explicit argument -
  1958 the current theory context is used; assumptions are no longer returned
  1959 at the ML-level unless one of them starts with ==> or !!; it is
  1960 recommended to convert to these new commands using isatool fixgoal
  1961 (backup your sources first!);
  1962 
  1963 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1964 the current theory context, and 'theory' to lookup stored theories;
  1965 
  1966 * new theory section 'locale' for declaring constants, assumptions and
  1967 definitions that have local scope;
  1968 
  1969 * new theory section 'nonterminals' for purely syntactic types;
  1970 
  1971 * new theory section 'setup' for generic ML setup functions
  1972 (e.g. package initialization);
  1973 
  1974 * the distribution now includes Isabelle icons: see
  1975 lib/logo/isabelle-{small,tiny}.xpm;
  1976 
  1977 * isatool install - install binaries with absolute references to
  1978 ISABELLE_HOME/bin;
  1979 
  1980 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1981 
  1982 * print mode 'emacs' reserved for Isamode;
  1983 
  1984 * support multiple print (ast) translations per constant name;
  1985 
  1986 * theorems involving oracles are now printed with a suffixed [!];
  1987 
  1988 
  1989 *** HOL ***
  1990 
  1991 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1992 
  1993 * HOL/inductive package reorganized and improved: now supports mutual
  1994 definitions such as
  1995 
  1996   inductive EVEN ODD
  1997     intrs
  1998       null "0 : EVEN"
  1999       oddI "n : EVEN ==> Suc n : ODD"
  2000       evenI "n : ODD ==> Suc n : EVEN"
  2001 
  2002 new theorem list "elims" contains an elimination rule for each of the
  2003 recursive sets; inductive definitions now handle disjunctive premises
  2004 correctly (also ZF);
  2005 
  2006 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2007 "mutual_induct" no longer exists - the induction rule is always
  2008 contained in "induct";
  2009 
  2010 
  2011 * HOL/datatype package re-implemented and greatly improved: now
  2012 supports mutually recursive datatypes such as
  2013 
  2014   datatype
  2015     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2016             | SUM ('a aexp) ('a aexp)
  2017             | DIFF ('a aexp) ('a aexp)
  2018             | NUM 'a
  2019   and
  2020     'a bexp = LESS ('a aexp) ('a aexp)
  2021             | AND ('a bexp) ('a bexp)
  2022             | OR ('a bexp) ('a bexp)
  2023 
  2024 as well as indirectly recursive datatypes such as
  2025 
  2026   datatype
  2027     ('a, 'b) term = Var 'a
  2028                   | App 'b ((('a, 'b) term) list)
  2029 
  2030 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2031 induction on mutually / indirectly recursive datatypes.
  2032 
  2033 Primrec equations are now stored in theory and can be accessed via
  2034 <function_name>.simps.
  2035 
  2036 INCOMPATIBILITIES:
  2037 
  2038   - Theories using datatypes must now have theory Datatype as an
  2039     ancestor.
  2040   - The specific <typename>.induct_tac no longer exists - use the
  2041     generic induct_tac instead.
  2042   - natE has been renamed to nat.exhaust - use exhaust_tac
  2043     instead of res_inst_tac ... natE. Note that the variable
  2044     names in nat.exhaust differ from the names in natE, this
  2045     may cause some "fragile" proofs to fail.
  2046   - The theorems split_<typename>_case and split_<typename>_case_asm
  2047     have been renamed to <typename>.split and <typename>.split_asm.
  2048   - Since default sorts of type variables are now handled correctly,
  2049     some datatype definitions may have to be annotated with explicit
  2050     sort constraints.
  2051   - Primrec definitions no longer require function name and type
  2052     of recursive argument.
  2053 
  2054 Consider using isatool fixdatatype to adapt your theories and proof
  2055 scripts to the new package (backup your sources first!).
  2056 
  2057 
  2058 * HOL/record package: considerably improved implementation; now
  2059 includes concrete syntax for record types, terms, updates; theorems
  2060 for surjective pairing and splitting !!-bound record variables; proof
  2061 support is as follows:
  2062 
  2063   1) standard conversions (selectors or updates applied to record
  2064 constructor terms) are part of the standard simpset;
  2065 
  2066   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2067 made part of standard simpset and claset via addIffs;
  2068 
  2069   3) a tactic for record field splitting (record_split_tac) is part of
  2070 the standard claset (addSWrapper);
  2071 
  2072 To get a better idea about these rules you may retrieve them via
  2073 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2074 the name of your record type.
  2075 
  2076 The split tactic 3) conceptually simplifies by the following rule:
  2077 
  2078   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2079 
  2080 Thus any record variable that is bound by meta-all will automatically
  2081 blow up into some record constructor term, consequently the
  2082 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2083 solve record problems automatically.
  2084 
  2085 
  2086 * reorganized the main HOL image: HOL/Integ and String loaded by
  2087 default; theory Main includes everything;
  2088 
  2089 * automatic simplification of integer sums and comparisons, using cancellation;
  2090 
  2091 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2092 
  2093 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2094 
  2095 * many new identities for unions, intersections, set difference, etc.;
  2096 
  2097 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2098 called split_if, split_split, split_sum_case and split_nat_case (to go
  2099 with add/delsplits);
  2100 
  2101 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2102 (?x::unit) = (); this is made part of the default simpset, which COULD
  2103 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2104 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2105 unit_abs_eta_conv is added in order to counter the effect of
  2106 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2107 %u.f();
  2108 
  2109 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2110 makes more sense);
  2111 
  2112 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2113   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2114   disjointness reasoning but breaking a few old proofs.
  2115 
  2116 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2117 to 'converse' from 'inverse' (for compatibility with ZF and some
  2118 literature);
  2119 
  2120 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2121 the well-founded relation;
  2122 
  2123 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2124     Compl A.  The "Compl" syntax remains available as input syntax for this
  2125     release ONLY.
  2126 
  2127 * HOL/Update: new theory of function updates:
  2128     f(a:=b) == %x. if x=a then b else f x
  2129 may also be iterated as in f(a:=b,c:=d,...);
  2130 
  2131 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2132 
  2133 * HOL/List:
  2134   - new function list_update written xs[i:=v] that updates the i-th
  2135     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2136   - new function `upt' written [i..j(] which generates the list
  2137     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2138     bound write [i..j], which is a shorthand for [i..j+1(].
  2139   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2140 
  2141 * HOL/Arith:
  2142   - removed 'pred' (predecessor) function;
  2143   - generalized some theorems about n-1;
  2144   - many new laws about "div" and "mod";
  2145   - new laws about greatest common divisors (see theory ex/Primes);
  2146 
  2147 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2148 instead of "inverse";
  2149 
  2150 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2151   of the multiset ordering;
  2152 
  2153 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2154   (not included by default);
  2155 
  2156 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2157 
  2158 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2159   programs, i.e. different program variables may have different types.
  2160 
  2161 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2162   [previously, this check worked only if the rewrite rule was unconditional]
  2163   Now rew can involve either definitions or equalities (either == or =).
  2164 
  2165 
  2166 *** ZF ***
  2167 
  2168 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2169   only the theorems proved on ZF.ML;
  2170 
  2171 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2172   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2173   disjointness reasoning but breaking a few old proofs.
  2174 
  2175 * ZF/Update: new theory of function updates
  2176     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2177   may also be iterated as in f(a:=b,c:=d,...);
  2178 
  2179 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2180 
  2181 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2182   [previously, this check worked only if the rewrite rule was unconditional]
  2183   Now rew can involve either definitions or equalities (either == or =).
  2184 
  2185 * case_tac provided for compatibility with HOL
  2186     (like the old excluded_middle_tac, but with subgoals swapped)
  2187 
  2188 
  2189 *** Internal programming interfaces ***
  2190 
  2191 * Pure: several new basic modules made available for general use, see
  2192 also src/Pure/README;
  2193 
  2194 * improved the theory data mechanism to support encapsulation (data
  2195 kind name replaced by private Object.kind, acting as authorization
  2196 key); new type-safe user interface via functor TheoryDataFun; generic
  2197 print_data function becomes basically useless;
  2198 
  2199 * removed global_names compatibility flag -- all theory declarations
  2200 are qualified by default;
  2201 
  2202 * module Pure/Syntax now offers quote / antiquote translation
  2203 functions (useful for Hoare logic etc. with implicit dependencies);
  2204 see HOL/ex/Antiquote for an example use;
  2205 
  2206 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2207 cterm -> thm;
  2208 
  2209 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2210 subgoal;
  2211 
  2212 * Display.print_goals function moved to Locale.print_goals;
  2213 
  2214 * standard print function for goals supports current_goals_markers
  2215 variable for marking begin of proof, end of proof, start of goal; the
  2216 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2217 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2218 for example;
  2219 
  2220 
  2221 
  2222 New in Isabelle98 (January 1998)
  2223 --------------------------------
  2224 
  2225 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2226 
  2227 * changed lexical syntax of terms / types: dots made part of long
  2228 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2229 
  2230 * simpset (and claset) reference variable replaced by functions
  2231 simpset / simpset_ref;
  2232 
  2233 * no longer supports theory aliases (via merge) and non-trivial
  2234 implicit merge of thms' signatures;
  2235 
  2236 * most internal names of constants changed due to qualified names;
  2237 
  2238 * changed Pure/Sequence interface (see Pure/seq.ML);
  2239 
  2240 
  2241 *** General Changes ***
  2242 
  2243 * hierachically structured name spaces (for consts, types, axms, thms
  2244 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2245 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2246 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2247 long_names for fully qualified output names; NOTE: ML programs
  2248 (special tactics, packages etc.) referring to internal names may have
  2249 to be adapted to cope with fully qualified names; in case of severe
  2250 backward campatibility problems try setting 'global_names' at compile
  2251 time to have enrything declared within a flat name space; one may also
  2252 fine tune name declarations in theories via the 'global' and 'local'
  2253 section;
  2254 
  2255 * reimplemented the implicit simpset and claset using the new anytype
  2256 data filed in signatures; references simpset:simpset ref etc. are
  2257 replaced by functions simpset:unit->simpset and
  2258 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2259 to patch your ML files accordingly;
  2260 
  2261 * HTML output now includes theory graph data for display with Java
  2262 applet or isatool browser; data generated automatically via isatool
  2263 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2264 
  2265 * defs may now be conditional; improved rewrite_goals_tac to handle
  2266 conditional equations;
  2267 
  2268 * defs now admits additional type arguments, using TYPE('a) syntax;
  2269 
  2270 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2271 creates a new theory node; implicit merge of thms' signatures is
  2272 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2273 transfer:theory->thm->thm in (rare) cases;
  2274 
  2275 * improved handling of draft signatures / theories; draft thms (and
  2276 ctyps, cterms) are automatically promoted to real ones;
  2277 
  2278 * slightly changed interfaces for oracles: admit many per theory, named
  2279 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2280 
  2281 * print_goals: optional output of const types (set show_consts and
  2282 show_types);
  2283 
  2284 * improved output of warnings (###) and errors (***);
  2285 
  2286 * subgoal_tac displays a warning if the new subgoal has type variables;
  2287 
  2288 * removed old README and Makefiles;
  2289 
  2290 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2291 
  2292 * removed obsolete init_pps and init_database;
  2293 
  2294 * deleted the obsolete tactical STATE, which was declared by
  2295     fun STATE tacfun st = tacfun st st;
  2296 
  2297 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2298 (which abbreviates $HOME);
  2299 
  2300 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2301 use isatool fixseq to adapt your ML programs (this works for fully
  2302 qualified references to the Sequence structure only!);
  2303 
  2304 * use_thy no longer requires writable current directory; it always
  2305 reloads .ML *and* .thy file, if either one is out of date;
  2306 
  2307 
  2308 *** Classical Reasoner ***
  2309 
  2310 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2311 tactics that use classical reasoning to simplify a subgoal without
  2312 splitting it into several subgoals;
  2313 
  2314 * Safe_tac: like safe_tac but uses the default claset;
  2315 
  2316 
  2317 *** Simplifier ***
  2318 
  2319 * added simplification meta rules:
  2320     (asm_)(full_)simplify: simpset -> thm -> thm;
  2321 
  2322 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2323 logics (again);
  2324 
  2325 * added prems argument to simplification procedures;
  2326 
  2327 * HOL, FOL, ZF: added infix function `addsplits':
  2328   instead of `<simpset> setloop (split_tac <thms>)'
  2329   you can simply write `<simpset> addsplits <thms>'
  2330 
  2331 
  2332 *** Syntax ***
  2333 
  2334 * TYPE('a) syntax for type reflection terms;
  2335 
  2336 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2337 
  2338 * pretty printer: changed order of mixfix annotation preference (again!);
  2339 
  2340 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2341 
  2342 
  2343 *** HOL ***
  2344 
  2345 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2346   with `addloop' of the simplifier to faciliate case splitting in premises.
  2347 
  2348 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2349 
  2350 * HOL/Auth: new protocol proofs including some for the Internet
  2351   protocol TLS;
  2352 
  2353 * HOL/Map: new theory of `maps' a la VDM;
  2354 
  2355 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2356 cancelling out common nat summands from =, <, <= (in)equalities, or
  2357 differences; simplification procedures nat_cancel_factor for
  2358 cancelling common factor from =, <, <= (in)equalities over natural
  2359 sums; nat_cancel contains both kinds of procedures, it is installed by
  2360 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2361 
  2362 * HOL/simplifier: terms of the form
  2363   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2364   are rewritten to
  2365   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2366   and those of the form
  2367   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2368   are rewritten to
  2369   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2370 
  2371 * HOL/datatype
  2372   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2373 
  2374   P(t_case f1 ... fn x) =
  2375      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2376         ...
  2377        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2378      )
  2379 
  2380   and a theorem `split_t_case_asm' of the form
  2381 
  2382   P(t_case f1 ... fn x) =
  2383     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2384         ...
  2385        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2386      )
  2387   which can be added to a simpset via `addsplits'. The existing theorems
  2388   expand_list_case and expand_option_case have been renamed to
  2389   split_list_case and split_option_case.
  2390 
  2391 * HOL/Arithmetic:
  2392   - `pred n' is automatically converted to `n-1'.
  2393     Users are strongly encouraged not to use `pred' any longer,
  2394     because it will disappear altogether at some point.
  2395   - Users are strongly encouraged to write "0 < n" rather than
  2396     "n ~= 0". Theorems and proof tools have been modified towards this
  2397     `standard'.
  2398 
  2399 * HOL/Lists:
  2400   the function "set_of_list" has been renamed "set" (and its theorems too);
  2401   the function "nth" now takes its arguments in the reverse order and
  2402   has acquired the infix notation "!" as in "xs!n".
  2403 
  2404 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2405 
  2406 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2407   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2408 
  2409 * HOL/record: extensible records with schematic structural subtyping
  2410 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2411 still lacks various theorems and concrete record syntax;
  2412 
  2413 
  2414 *** HOLCF ***
  2415 
  2416 * removed "axioms" and "generated by" sections;
  2417 
  2418 * replaced "ops" section by extended "consts" section, which is capable of
  2419   handling the continuous function space "->" directly;
  2420 
  2421 * domain package:
  2422   . proves theorems immediately and stores them in the theory,
  2423   . creates hierachical name space,
  2424   . now uses normal mixfix annotations (instead of cinfix...),
  2425   . minor changes to some names and values (for consistency),
  2426   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2427   . separator between mutual domain defs: changed "," to "and",
  2428   . improved handling of sort constraints;  now they have to
  2429     appear on the left-hand side of the equations only;
  2430 
  2431 * fixed LAM <x,y,zs>.b syntax;
  2432 
  2433 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2434 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2435 
  2436 
  2437 *** FOL and ZF ***
  2438 
  2439 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2440   with `addloop' of the simplifier to faciliate case splitting in premises.
  2441 
  2442 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2443 in HOL, they strip ALL and --> from proved theorems;
  2444 
  2445 
  2446 
  2447 New in Isabelle94-8 (May 1997)
  2448 ------------------------------
  2449 
  2450 *** General Changes ***
  2451 
  2452 * new utilities to build / run / maintain Isabelle etc. (in parts
  2453 still somewhat experimental); old Makefiles etc. still functional;
  2454 
  2455 * new 'Isabelle System Manual';
  2456 
  2457 * INSTALL text, together with ./configure and ./build scripts;
  2458 
  2459 * reimplemented type inference for greater efficiency, better error
  2460 messages and clean internal interface;
  2461 
  2462 * prlim command for dealing with lots of subgoals (an easier way of
  2463 setting goals_limit);
  2464 
  2465 
  2466 *** Syntax ***
  2467 
  2468 * supports alternative (named) syntax tables (parser and pretty
  2469 printer); internal interface is provided by add_modesyntax(_i);
  2470 
  2471 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2472 be used in conjunction with the Isabelle symbol font; uses the
  2473 "symbols" syntax table;
  2474 
  2475 * added token_translation interface (may translate name tokens in
  2476 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2477 the current print_mode); IMPORTANT: user print translation functions
  2478 are responsible for marking newly introduced bounds
  2479 (Syntax.mark_boundT);
  2480 
  2481 * token translations for modes "xterm" and "xterm_color" that display
  2482 names in bold, underline etc. or colors (which requires a color
  2483 version of xterm);
  2484 
  2485 * infixes may now be declared with names independent of their syntax;
  2486 
  2487 * added typed_print_translation (like print_translation, but may
  2488 access type of constant);
  2489 
  2490 
  2491 *** Classical Reasoner ***
  2492 
  2493 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2494 some limitations.  Blast_tac...
  2495   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2496   + ignores elimination rules that don't have the correct format
  2497         (the conclusion MUST be a formula variable)
  2498   + ignores types, which can make HOL proofs fail
  2499   + rules must not require higher-order unification, e.g. apply_type in ZF
  2500     [message "Function Var's argument not a bound variable" relates to this]
  2501   + its proof strategy is more general but can actually be slower
  2502 
  2503 * substitution with equality assumptions no longer permutes other
  2504 assumptions;
  2505 
  2506 * minor changes in semantics of addafter (now called addaltern); renamed
  2507 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2508 (and access functions for it);
  2509 
  2510 * improved combination of classical reasoner and simplifier:
  2511   + functions for handling clasimpsets
  2512   + improvement of addss: now the simplifier is called _after_ the
  2513     safe steps.
  2514   + safe variant of addss called addSss: uses safe simplifications
  2515     _during_ the safe steps. It is more complete as it allows multiple
  2516     instantiations of unknowns (e.g. with slow_tac).
  2517 
  2518 *** Simplifier ***
  2519 
  2520 * added interface for simplification procedures (functions that
  2521 produce *proven* rewrite rules on the fly, depending on current
  2522 redex);
  2523 
  2524 * ordering on terms as parameter (used for ordered rewriting);
  2525 
  2526 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2527 
  2528 * the solver is now split into a safe and an unsafe part.
  2529 This should be invisible for the normal user, except that the
  2530 functions setsolver and addsolver have been renamed to setSolver and
  2531 addSolver; added safe_asm_full_simp_tac;
  2532 
  2533 
  2534 *** HOL ***
  2535 
  2536 * a generic induction tactic `induct_tac' which works for all datatypes and
  2537 also for type `nat';
  2538 
  2539 * a generic case distinction tactic `exhaust_tac' which works for all
  2540 datatypes and also for type `nat';
  2541 
  2542 * each datatype comes with a function `size';
  2543 
  2544 * patterns in case expressions allow tuple patterns as arguments to
  2545 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2546 
  2547 * primrec now also works with type nat;
  2548 
  2549 * recdef: a new declaration form, allows general recursive functions to be
  2550 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2551 
  2552 * the constant for negation has been renamed from "not" to "Not" to
  2553 harmonize with FOL, ZF, LK, etc.;
  2554 
  2555 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2556 infinite lists;
  2557 
  2558 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2559 
  2560 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2561 problems in commutative rings, using axiomatic type classes for + and *;
  2562 
  2563 * more examples in HOL/MiniML and HOL/Auth;
  2564 
  2565 * more default rewrite rules for quantifiers, union/intersection;
  2566 
  2567 * a new constant `arbitrary == @x.False';
  2568 
  2569 * HOLCF/IOA replaces old HOL/IOA;
  2570 
  2571 * HOLCF changes: derived all rules and arities
  2572   + axiomatic type classes instead of classes
  2573   + typedef instead of faking type definitions
  2574   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2575   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2576   + eliminated the types void, one, tr
  2577   + use unit lift and bool lift (with translations) instead of one and tr
  2578   + eliminated blift from Lift3.thy (use Def instead of blift)
  2579   all eliminated rules are derived as theorems --> no visible changes ;
  2580 
  2581 
  2582 *** ZF ***
  2583 
  2584 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2585 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2586 as ZF_cs addSIs [equalityI];
  2587 
  2588 
  2589 
  2590 New in Isabelle94-7 (November 96)
  2591 ---------------------------------
  2592 
  2593 * allowing negative levels (as offsets) in prlev and choplev;
  2594 
  2595 * super-linear speedup for large simplifications;
  2596 
  2597 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2598 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2599 FAIL); can suppress it using the command Delsimps (ex_simps @
  2600 all_simps); De Morgan laws are also now included, by default;
  2601 
  2602 * improved printing of ==>  :  ~:
  2603 
  2604 * new object-logic "Sequents" adds linear logic, while replacing LK
  2605 and Modal (thanks to Sara Kalvala);
  2606 
  2607 * HOL/Auth: correctness proofs for authentication protocols;
  2608 
  2609 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2610 examples on HOL/Auth);
  2611 
  2612 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2613 the rewriter and classical reasoner simultaneously;
  2614 
  2615 * function uresult no longer returns theorems in "standard" format;
  2616 regain previous version by: val uresult = standard o uresult;
  2617 
  2618 
  2619 
  2620 New in Isabelle94-6
  2621 -------------------
  2622 
  2623 * oracles -- these establish an interface between Isabelle and trusted
  2624 external reasoners, which may deliver results as theorems;
  2625 
  2626 * proof objects (in particular record all uses of oracles);
  2627 
  2628 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2629 
  2630 * "constdefs" section in theory files;
  2631 
  2632 * "primrec" section (HOL) no longer requires names;
  2633 
  2634 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2635 
  2636 
  2637 
  2638 New in Isabelle94-5
  2639 -------------------
  2640 
  2641 * reduced space requirements;
  2642 
  2643 * automatic HTML generation from theories;
  2644 
  2645 * theory files no longer require "..." (quotes) around most types;
  2646 
  2647 * new examples, including two proofs of the Church-Rosser theorem;
  2648 
  2649 * non-curried (1994) version of HOL is no longer distributed;
  2650 
  2651 
  2652 
  2653 New in Isabelle94-4
  2654 -------------------
  2655 
  2656 * greatly reduced space requirements;
  2657 
  2658 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2659 
  2660 * searchable theorem database (see the section "Retrieving theorems" on
  2661 page 8 of the Reference Manual);
  2662 
  2663 * new examples, including Grabczewski's monumental case study of the
  2664 Axiom of Choice;
  2665 
  2666 * The previous version of HOL renamed to Old_HOL;
  2667 
  2668 * The new version of HOL (previously called CHOL) uses a curried syntax
  2669 for functions.  Application looks like f a b instead of f(a,b);
  2670 
  2671 * Mutually recursive inductive definitions finally work in HOL;
  2672 
  2673 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2674 translates to the operator "split";
  2675 
  2676 
  2677 
  2678 New in Isabelle94-3
  2679 -------------------
  2680 
  2681 * new infix operator, addss, allowing the classical reasoner to
  2682 perform simplification at each step of its search.  Example:
  2683         fast_tac (cs addss ss)
  2684 
  2685 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2686 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2687 look like (a,b) instead of <a,b>;
  2688 
  2689 * PLEASE NOTE: CHOL will eventually replace HOL!
  2690 
  2691 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2692 It translates to the operator "split".  A new theory of integers is available;
  2693 
  2694 * In ZF, integer numerals now denote two's-complement binary integers.
  2695 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2696 
  2697 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2698 of the Axiom of Choice;
  2699 
  2700 
  2701 
  2702 New in Isabelle94-2
  2703 -------------------
  2704 
  2705 * Significantly faster resolution;
  2706 
  2707 * the different sections in a .thy file can now be mixed and repeated
  2708 freely;
  2709 
  2710 * Database of theorems for FOL, HOL and ZF.  New
  2711 commands including qed, qed_goal and bind_thm store theorems in the database.
  2712 
  2713 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2714 a given theory (thms_of), or find out what theory a theorem was proved in
  2715 (theory_of_thm);
  2716 
  2717 * Bugs fixed in the inductive definition and datatype packages;
  2718 
  2719 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2720 and HOL_dup_cs obsolete;
  2721 
  2722 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2723 have been removed;
  2724 
  2725 * Simpler definition of function space in ZF;
  2726 
  2727 * new results about cardinal and ordinal arithmetic in ZF;
  2728 
  2729 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2730 types;
  2731 
  2732 
  2733 $Id$