NEWS
author wenzelm
Thu Jun 10 20:17:07 2004 +0200 (2004-06-10)
changeset 14919 0f5fde03e2b5
parent 14917 b54b11ebe220
child 14934 bf9f525d4821
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.
    56 
    57 * ML: output via the Isabelle channels of writeln/warning/error
    58   etc. is now passed through Output.output, with a hook for arbitrary
    59   transformations depending on the print_mode (cf. Output.add_mode --
    60   the first active mode that provides a output function wins).
    61   Already formatted output may be embedded into further text via
    62   Output.raw; the result of Pretty.string_of/str_of and derived
    63   functions (string_of_term/cterm/thm etc.) is already marked raw to
    64   accommodate easy composition of diagnostic messages etc.
    65   Programmers rarely need to care about Output.output or Output.raw at
    66   all, with some notable exceptions: Output.output is required when
    67   bypassing the standard channels (writeln etc.), or in token
    68   translations to produce properly formatted results; Output.raw is
    69   required when capturing already output material that will eventually
    70   be presented to the user a second time.
    71 
    72 
    73 *** HOL ***
    74 
    75 * HOL/record: reimplementation of records. Improved scalability for
    76   records with many fields, avoiding performance problems for type
    77   inference. Records are no longer composed of nested field types, but
    78   of nested extension types. Therefore the record type only grows
    79   linear in the number of extensions and not in the number of fields.
    80   The top-level (users) view on records is preserved.  Potential
    81   INCOMPATIBILITY only in strange cases, where the theory depends on
    82   the old record representation. The type generated for a record is
    83   called <record_name>_ext_type.
    84 
    85 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
    86 
    87   syntax (epsilon)
    88     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
    89 
    90   The symbol \<some> is displayed as the alternative epsilon of LaTeX
    91   and x-symbol; use option '-m epsilon' to get it actually printed.
    92   Moreover, the mathematically important symbolic identifier
    93   \<epsilon> becomes available as variable, constant etc.
    94 
    95 * Simplifier: "record_upd_simproc" for simplification of multiple
    96   record updates enabled by default.  INCOMPATIBILITY: old proofs
    97   break occasionally, since simplification is more powerful by
    98   default.
    99 
   100 
   101 *** HOLCF ***
   102 
   103 * HOLCF: discontinued special version of 'constdefs' (which used to
   104   support continuous functions) in favor of the general Pure one with
   105   full type-inference.
   106 
   107 
   108 *** ZF ***
   109 
   110 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the First
   111   Isomorphism Theorem (on quotienting by the kernel of a homomorphism).
   112 
   113 
   114 
   115 New in Isabelle2004 (April 2004)
   116 --------------------------------
   117 
   118 *** General ***
   119 
   120 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   121   Replaces linorder.ML.
   122 
   123 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   124   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   125   (\<a>...\<z>), are now considered normal letters, and can therefore
   126   be used anywhere where an ASCII letter (a...zA...Z) has until
   127   now. COMPATIBILITY: This obviously changes the parsing of some
   128   terms, especially where a symbol has been used as a binder, say
   129   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   130   as an identifier.  Fix it by inserting a space around former
   131   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   132   existing theory and ML files.
   133 
   134 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   135 
   136 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   137   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   138   a normal (but invisible) letter. For multiple letter subscripts repeat
   139   \<^isub> like this: x\<^isub>1\<^isub>2.
   140 
   141 * Pure: There are now sub-/superscripts that can span more than one
   142   character. Text between \<^bsub> and \<^esub> is set in subscript in
   143   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   144   superscript. The new control characters are not identifier parts.
   145 
   146 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   147   content of "..." to the latex file instead of \isacntrl... . The "..."
   148   may consist of any printable characters excluding the end bracket >.
   149 
   150 * Pure: Using new Isar command "finalconsts" (or the ML functions
   151   Theory.add_finals or Theory.add_finals_i) it is now possible to
   152   declare constants "final", which prevents their being given a definition
   153   later.  It is useful for constants whose behaviour is fixed axiomatically
   154   rather than definitionally, such as the meta-logic connectives.
   155 
   156 * Pure: 'instance' now handles general arities with general sorts
   157   (i.e. intersections of classes),
   158 
   159 * Presentation: generated HTML now uses a CSS style sheet to make layout
   160   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   161   It can be changed to alter the colors/layout of generated pages.
   162 
   163 
   164 *** Isar ***
   165 
   166 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   167   cut_tac, subgoal_tac and thin_tac:
   168   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   169     locales are no longer forced to write Isar proof scripts.
   170     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   171     emulations.
   172   - INCOMPATIBILITY: names of variables to be instantiated may no
   173     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   174     This is consistent with the instantiation attribute "where".
   175 
   176 * Attributes "where" and "of":
   177   - Now take type variables of instantiated theorem into account when reading
   178     the instantiation string.  This fixes a bug that caused instantiated
   179     theorems to have too special types in some circumstances.
   180   - "where" permits explicit instantiations of type variables.
   181 
   182 * Calculation commands "moreover" and "also" no longer interfere with
   183   current facts ("this"), admitting arbitrary combinations with "then"
   184   and derived forms.
   185 
   186 * Locales:
   187   - Goal statements involving the context element "includes" no longer
   188     generate theorems with internal delta predicates (those ending on
   189     "_axioms") in the premise.
   190     Resolve particular premise with <locale>.intro to obtain old form.
   191   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   192     specification and "includes" elements in goal statement.
   193   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   194     [intro?] and [elim?] (respectively) by default.
   195   - Experimental command for instantiation of locales in proof contexts:
   196         instantiate <label>[<attrs>]: <loc>
   197     Instantiates locale <loc> and adds all its theorems to the current context
   198     taking into account their attributes.  Label and attrs are optional
   199     modifiers, like in theorem declarations.  If present, names of
   200     instantiated theorems are qualified with <label>, and the attributes
   201     <attrs> are applied after any attributes these theorems might have already.
   202       If the locale has assumptions, a chained fact of the form
   203     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   204     are derived.  The command does not support old-style locales declared
   205     with "locale (open)".
   206       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   207 
   208 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   209   (Isar) contexts.
   210 
   211 
   212 *** HOL ***
   213 
   214 * Proof import: new image HOL4 contains the imported library from
   215   the HOL4 system with about 2500 theorems. It is imported by
   216   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   217   can be used like any other Isabelle image.  See
   218   HOL/Import/HOL/README for more information.
   219 
   220 * Simplifier:
   221   - Much improved handling of linear and partial orders.
   222     Reasoners for linear and partial orders are set up for type classes
   223     "linorder" and "order" respectively, and are added to the default simpset
   224     as solvers.  This means that the simplifier can build transitivity chains
   225     to solve goals from the assumptions.
   226   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   227     of blast or auto after simplification become unnecessary because the goal
   228     is solved by simplification already.
   229 
   230 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   231     all proved in axiomatic type classes for semirings, rings and fields.
   232 
   233 * Numerics:
   234   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   235     now formalized using the Ring_and_Field theory mentioned above.
   236   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   237     than before, because now they are set up once in a generic manner.
   238   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   239     Look for the general versions in Ring_and_Field (and Power if they concern
   240     exponentiation).
   241 
   242 * Type "rat" of the rational numbers is now available in HOL-Complex.
   243 
   244 * Records:
   245   - Record types are now by default printed with their type abbreviation
   246     instead of the list of all field types. This can be configured via
   247     the reference "print_record_type_abbr".
   248   - Simproc "record_upd_simproc" for simplification of multiple updates added
   249     (not enabled by default).
   250   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   251     EX x. x = sel r to True (not enabled by default).
   252   - Tactic "record_split_simp_tac" to split and simplify records added.
   253 
   254 * 'specification' command added, allowing for definition by
   255   specification.  There is also an 'ax_specification' command that
   256   introduces the new constants axiomatically.
   257 
   258 * arith(_tac) is now able to generate counterexamples for reals as well.
   259 
   260 * HOL-Algebra: new locale "ring" for non-commutative rings.
   261 
   262 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   263   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   264 
   265 * HOL-Matrix: a first theory for matrices in HOL with an application of
   266   matrix theory to linear programming.
   267 
   268 * Unions and Intersections:
   269   The x-symbol output syntax of UN and INT has been changed
   270   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   271   i.e. the index formulae has become a subscript, like in normal math.
   272   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   273   The subscript version is also accepted as input syntax.
   274 
   275 * Unions and Intersections over Intervals:
   276   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   277   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   278   like in normal math, and corresponding versions for < and for intersection.
   279 
   280 * ML: the legacy theory structures Int and List have been removed. They had
   281   conflicted with ML Basis Library structures having the same names.
   282 
   283 * 'refute' command added to search for (finite) countermodels.  Only works
   284   for a fragment of HOL.  The installation of an external SAT solver is
   285   highly recommended.  See "HOL/Refute.thy" for details.
   286 
   287 * 'quickcheck' command: Allows to find counterexamples by evaluating
   288   formulae under an assignment of free variables to random values.
   289   In contrast to 'refute', it can deal with inductive datatypes,
   290   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   291   for examples.
   292 
   293 
   294 *** HOLCF ***
   295 
   296 * Streams now come with concatenation and are part of the HOLCF image
   297 
   298 
   299 
   300 New in Isabelle2003 (May 2003)
   301 ------------------------------
   302 
   303 *** General ***
   304 
   305 * Provers/simplifier:
   306 
   307   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   308     Assumptions are now subject to complete mutual simplification,
   309     not just from left to right. The simplifier now preserves
   310     the order of assumptions.
   311 
   312     Potential INCOMPATIBILITY:
   313 
   314     -- simp sometimes diverges where the old version did
   315        not, e.g. invoking simp on the goal
   316 
   317         [| P (f x); y = x; f x = f y |] ==> Q
   318 
   319        now gives rise to the infinite reduction sequence
   320 
   321         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   322 
   323        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   324        kind of problem.
   325 
   326     -- Tactics combining classical reasoner and simplification (such as auto)
   327        are also affected by this change, because many of them rely on
   328        simp. They may sometimes diverge as well or yield a different numbers
   329        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   330        in case of problems. Sometimes subsequent calls to the classical
   331        reasoner will fail because a preceeding call to the simplifier too
   332        eagerly simplified the goal, e.g. deleted redundant premises.
   333 
   334   - The simplifier trace now shows the names of the applied rewrite rules
   335 
   336   - You can limit the number of recursive invocations of the simplifier
   337     during conditional rewriting (where the simplifie tries to solve the
   338     conditions before applying the rewrite rule):
   339     ML "simp_depth_limit := n"
   340     where n is an integer. Thus you can force termination where previously
   341     the simplifier would diverge.
   342 
   343   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   344 
   345   - No longer aborts on failed congruence proof.  Instead, the
   346     congruence is ignored.
   347 
   348 * Pure: New generic framework for extracting programs from constructive
   349   proofs. See HOL/Extraction.thy for an example instantiation, as well
   350   as HOL/Extraction for some case studies.
   351 
   352 * Pure: The main goal of the proof state is no longer shown by default, only
   353 the subgoals. This behaviour is controlled by a new flag.
   354    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   355 (ML: Proof.show_main_goal).
   356 
   357 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   358 rules whose conclusion matches subgoal 1:
   359       PG menu: Isabelle/Isar -> Show me -> matching rules
   360 The rules are ordered by how closely they match the subgoal.
   361 In particular, rules that solve a subgoal outright are displayed first
   362 (or rather last, the way they are printed).
   363 (ML: ProofGeneral.print_intros())
   364 
   365 * Pure: New flag trace_unify_fail causes unification to print
   366 diagnostic information (PG: in trace buffer) when it fails. This is
   367 useful for figuring out why single step proofs like rule, erule or
   368 assumption failed.
   369 
   370 * Pure: Locale specifications now produce predicate definitions
   371 according to the body of text (covering assumptions modulo local
   372 definitions); predicate "loc_axioms" covers newly introduced text,
   373 while "loc" is cumulative wrt. all included locale expressions; the
   374 latter view is presented only on export into the global theory
   375 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   376 on the old view without predicates;
   377 
   378 * Pure: predefined locales "var" and "struct" are useful for sharing
   379 parameters (as in CASL, for example); just specify something like
   380 ``var x + var y + struct M'' as import;
   381 
   382 * Pure: improved thms_containing: proper indexing of facts instead of
   383 raw theorems; check validity of results wrt. current name space;
   384 include local facts of proof configuration (also covers active
   385 locales), cover fixed variables in index; may use "_" in term
   386 specification; an optional limit for the number of printed facts may
   387 be given (the default is 40);
   388 
   389 * Pure: disallow duplicate fact bindings within new-style theory files
   390 (batch-mode only);
   391 
   392 * Provers: improved induct method: assumptions introduced by case
   393 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   394 the goal statement); "foo" still refers to all facts collectively;
   395 
   396 * Provers: the function blast.overloaded has been removed: all constants
   397 are regarded as potentially overloaded, which improves robustness in exchange
   398 for slight decrease in efficiency;
   399 
   400 * Provers/linorder: New generic prover for transitivity reasoning over
   401 linear orders.  Note: this prover is not efficient!
   402 
   403 * Isar: preview of problems to finish 'show' now produce an error
   404 rather than just a warning (in interactive mode);
   405 
   406 
   407 *** HOL ***
   408 
   409 * arith(_tac)
   410 
   411  - Produces a counter example if it cannot prove a goal.
   412    Note that the counter example may be spurious if the goal is not a formula
   413    of quantifier-free linear arithmetic.
   414    In ProofGeneral the counter example appears in the trace buffer.
   415 
   416  - Knows about div k and mod k where k is a numeral of type nat or int.
   417 
   418  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   419    linear arithmetic fails. This takes account of quantifiers and divisibility.
   420    Presburger arithmetic can also be called explicitly via presburger(_tac).
   421 
   422 * simp's arithmetic capabilities have been enhanced a bit: it now
   423 takes ~= in premises into account (by performing a case split);
   424 
   425 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   426 are distributed over a sum of terms;
   427 
   428 * New tactic "trans_tac" and method "trans" instantiate
   429 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   430 "<=", "<" and "=").
   431 
   432 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   433 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   434 
   435 * 'typedef' command has new option "open" to suppress the set
   436 definition;
   437 
   438 * functions Min and Max on finite sets have been introduced (theory
   439 Finite_Set);
   440 
   441 * attribute [symmetric] now works for relations as well; it turns
   442 (x,y) : R^-1 into (y,x) : R, and vice versa;
   443 
   444 * induct over a !!-quantified statement (say !!x1..xn):
   445   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   446 
   447 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   448 %x. None. Warning: empty_def now refers to the previously hidden definition
   449 of the empty set.
   450 
   451 * Algebra: formalization of classical algebra.  Intended as base for
   452 any algebraic development in Isabelle.  Currently covers group theory
   453 (up to Sylow's theorem) and ring theory (Universal Property of
   454 Univariate Polynomials).  Contributions welcome;
   455 
   456 * GroupTheory: deleted, since its material has been moved to Algebra;
   457 
   458 * Complex: new directory of the complex numbers with numeric constants,
   459 nonstandard complex numbers, and some complex analysis, standard and
   460 nonstandard (Jacques Fleuriot);
   461 
   462 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   463 
   464 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   465 Fleuriot);
   466 
   467 * Real/HahnBanach: updated and adapted to locales;
   468 
   469 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   470 Gray and Kramer);
   471 
   472 * UNITY: added the Meier-Sanders theory of progress sets;
   473 
   474 * MicroJava: bytecode verifier and lightweight bytecode verifier
   475 as abstract algorithms, instantiated to the JVM;
   476 
   477 * Bali: Java source language formalization. Type system, operational
   478 semantics, axiomatic semantics. Supported language features:
   479 classes, interfaces, objects,virtual methods, static methods,
   480 static/instance fields, arrays, access modifiers, definite
   481 assignment, exceptions.
   482 
   483 
   484 *** ZF ***
   485 
   486 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   487 universe, etc.);
   488 
   489 * Main ZF: virtually all theories converted to new-style format;
   490 
   491 
   492 *** ML ***
   493 
   494 * Pure: Tactic.prove provides sane interface for internal proofs;
   495 omits the infamous "standard" operation, so this is more appropriate
   496 than prove_goalw_cterm in many situations (e.g. in simprocs);
   497 
   498 * Pure: improved error reporting of simprocs;
   499 
   500 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   501 up simprocs;
   502 
   503 
   504 *** Document preparation ***
   505 
   506 * uses \par instead of \\ for line breaks in theory text. This may
   507 shift some page breaks in large documents. To get the old behaviour
   508 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   509 
   510 * minimized dependencies of isabelle.sty and isabellesym.sty on
   511 other packages
   512 
   513 * \<euro> now needs package babel/greek instead of marvosym (which
   514 broke \Rightarrow)
   515 
   516 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   517 textcomp package)
   518 
   519 
   520 
   521 New in Isabelle2002 (March 2002)
   522 --------------------------------
   523 
   524 *** Document preparation ***
   525 
   526 * greatly simplified document preparation setup, including more
   527 graceful interpretation of isatool usedir -i/-d/-D options, and more
   528 instructive isatool mkdir; users should basically be able to get
   529 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   530 users may run a separate document processing stage manually like this:
   531 "isatool usedir -D output HOL Test && isatool document Test/output";
   532 
   533 * theory dependency graph may now be incorporated into documents;
   534 isatool usedir -g true will produce session_graph.eps/.pdf for use
   535 with \includegraphics of LaTeX;
   536 
   537 * proper spacing of consecutive markup elements, especially text
   538 blocks after section headings;
   539 
   540 * support bold style (for single symbols only), input syntax is like
   541 this: "\<^bold>\<alpha>" or "\<^bold>A";
   542 
   543 * \<bullet> is now output as bold \cdot by default, which looks much
   544 better in printed text;
   545 
   546 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   547 note that these symbols are currently unavailable in Proof General /
   548 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   549 
   550 * isatool latex no longer depends on changed TEXINPUTS, instead
   551 isatool document copies the Isabelle style files to the target
   552 location;
   553 
   554 
   555 *** Isar ***
   556 
   557 * Pure/Provers: improved proof by cases and induction;
   558   - 'case' command admits impromptu naming of parameters (such as
   559     "case (Suc n)");
   560   - 'induct' method divinates rule instantiation from the inductive
   561     claim; no longer requires excessive ?P bindings for proper
   562     instantiation of cases;
   563   - 'induct' method properly enumerates all possibilities of set/type
   564     rules; as a consequence facts may be also passed through *type*
   565     rules without further ado;
   566   - 'induct' method now derives symbolic cases from the *rulified*
   567     rule (before it used to rulify cases stemming from the internal
   568     atomized version); this means that the context of a non-atomic
   569     statement becomes is included in the hypothesis, avoiding the
   570     slightly cumbersome show "PROP ?case" form;
   571   - 'induct' may now use elim-style induction rules without chaining
   572     facts, using ``missing'' premises from the goal state; this allows
   573     rules stemming from inductive sets to be applied in unstructured
   574     scripts, while still benefitting from proper handling of non-atomic
   575     statements; NB: major inductive premises need to be put first, all
   576     the rest of the goal is passed through the induction;
   577   - 'induct' proper support for mutual induction involving non-atomic
   578     rule statements (uses the new concept of simultaneous goals, see
   579     below);
   580   - append all possible rule selections, but only use the first
   581     success (no backtracking);
   582   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   583   - undeclared rule case names default to numbers 1, 2, 3, ...;
   584   - added 'print_induct_rules' (covered by help item in recent Proof
   585     General versions);
   586   - moved induct/cases attributes to Pure, methods to Provers;
   587   - generic method setup instantiated for FOL and HOL;
   588 
   589 * Pure: support multiple simultaneous goal statements, for example
   590 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   591 meta-level mechanism, this acts as if several individual goals had
   592 been stated separately; in particular common proof methods need to be
   593 repeated in order to cover all claims; note that a single elimination
   594 step is *not* sufficient to establish the two conjunctions, so this
   595 fails:
   596 
   597   assume "A & B" then have A and B ..   (*".." fails*)
   598 
   599 better use "obtain" in situations as above; alternative refer to
   600 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   601 
   602 * Pure: proper integration with ``locales''; unlike the original
   603 version by Florian Kammüller, Isar locales package high-level proof
   604 contexts rather than raw logical ones (e.g. we admit to include
   605 attributes everywhere); operations on locales include merge and
   606 rename; support for implicit arguments (``structures''); simultaneous
   607 type-inference over imports and text; see also HOL/ex/Locales.thy for
   608 some examples;
   609 
   610 * Pure: the following commands have been ``localized'', supporting a
   611 target locale specification "(in name)": 'lemma', 'theorem',
   612 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   613 stored both within the locale and at the theory level (exported and
   614 qualified by the locale name);
   615 
   616 * Pure: theory goals may now be specified in ``long'' form, with
   617 ad-hoc contexts consisting of arbitrary locale elements. for example
   618 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   619 definitions may be given, too); the result is a meta-level rule with
   620 the context elements being discharged in the obvious way;
   621 
   622 * Pure: new proof command 'using' allows to augment currently used
   623 facts after a goal statement ('using' is syntactically analogous to
   624 'apply', but acts on the goal's facts only); this allows chained facts
   625 to be separated into parts given before and after a claim, as in
   626 ``from a and b have C using d and e <proof>'';
   627 
   628 * Pure: renamed "antecedent" case to "rule_context";
   629 
   630 * Pure: new 'judgment' command records explicit information about the
   631 object-logic embedding (used by several tools internally); no longer
   632 use hard-wired "Trueprop";
   633 
   634 * Pure: added 'corollary' command;
   635 
   636 * Pure: fixed 'token_translation' command;
   637 
   638 * Pure: removed obsolete 'exported' attribute;
   639 
   640 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   641 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   642 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   643 
   644 * Pure: method 'atomize' presents local goal premises as object-level
   645 statements (atomic meta-level propositions); setup controlled via
   646 rewrite rules declarations of 'atomize' attribute; example
   647 application: 'induct' method with proper rule statements in improper
   648 proof *scripts*;
   649 
   650 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   651 now consider the syntactic context of assumptions, giving a better
   652 chance to get type-inference of the arguments right (this is
   653 especially important for locales);
   654 
   655 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   656 mode;
   657 
   658 * Pure/obtain: the formal conclusion "thesis", being marked as
   659 ``internal'', may no longer be reference directly in the text;
   660 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   661 situations;
   662 
   663 * Pure: generic 'sym' attribute which declares a rule both as pure
   664 'elim?' and for the 'symmetric' operation;
   665 
   666 * Pure: marginal comments ``--'' may now occur just anywhere in the
   667 text; the fixed correlation with particular command syntax has been
   668 discontinued;
   669 
   670 * Pure: new method 'rules' is particularly well-suited for proof
   671 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   672 but often produces more compact proof terms with less detours;
   673 
   674 * Pure/Provers/classical: simplified integration with pure rule
   675 attributes and methods; the classical "intro?/elim?/dest?"
   676 declarations coincide with the pure ones; the "rule" method no longer
   677 includes classically swapped intros; "intro" and "elim" methods no
   678 longer pick rules from the context; also got rid of ML declarations
   679 AddXIs/AddXEs/AddXDs; all of this has some potential for
   680 INCOMPATIBILITY;
   681 
   682 * Provers/classical: attribute 'swapped' produces classical inversions
   683 of introduction rules;
   684 
   685 * Provers/simplifier: 'simplified' attribute may refer to explicit
   686 rules instead of full simplifier context; 'iff' attribute handles
   687 conditional rules;
   688 
   689 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   690 
   691 * HOL: 'recdef' now fails on unfinished automated proofs, use
   692 "(permissive)" option to recover old behavior;
   693 
   694 * HOL: 'inductive' no longer features separate (collective) attributes
   695 for 'intros' (was found too confusing);
   696 
   697 * HOL: properly declared induction rules less_induct and
   698 wf_induct_rule;
   699 
   700 
   701 *** HOL ***
   702 
   703 * HOL: moved over to sane numeral syntax; the new policy is as
   704 follows:
   705 
   706   - 0 and 1 are polymorphic constants, which are defined on any
   707   numeric type (nat, int, real etc.);
   708 
   709   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   710   binary representation internally;
   711 
   712   - type nat has special constructor Suc, and generally prefers Suc 0
   713   over 1::nat and Suc (Suc 0) over 2::nat;
   714 
   715 This change may cause significant problems of INCOMPATIBILITY; here
   716 are some hints on converting existing sources:
   717 
   718   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   719   entities, so expressions involving "-" (unary or binary minus) need
   720   to be spaced properly;
   721 
   722   - existing occurrences of "1" may need to be constraint "1::nat" or
   723   even replaced by Suc 0; similar for old "2";
   724 
   725   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   726 
   727   - remove all special provisions on numerals in proofs;
   728 
   729 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   730 representation (depends on bin_arith_simps in the default context);
   731 
   732 * HOL: symbolic syntax for x^2 (numeral 2);
   733 
   734 * HOL: the class of all HOL types is now called "type" rather than
   735 "term"; INCOMPATIBILITY, need to adapt references to this type class
   736 in axclass/classes, instance/arities, and (usually rare) occurrences
   737 in typings (of consts etc.); internally the class is called
   738 "HOL.type", ML programs should refer to HOLogic.typeS;
   739 
   740 * HOL/record package improvements:
   741   - new derived operations "fields" to build a partial record section,
   742     "extend" to promote a fixed record to a record scheme, and
   743     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   744     declared as simp by default;
   745   - shared operations ("more", "fields", etc.) now need to be always
   746     qualified) --- potential INCOMPATIBILITY;
   747   - removed "make_scheme" operations (use "make" with "extend") --
   748     INCOMPATIBILITY;
   749   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   750   - provides cases/induct rules for use with corresponding Isar
   751     methods (for concrete records, record schemes, concrete more
   752     parts, and schematic more parts -- in that order);
   753   - internal definitions directly based on a light-weight abstract
   754     theory of product types over typedef rather than datatype;
   755 
   756 * HOL: generic code generator for generating executable ML code from
   757 specifications; specific support for HOL constructs such as inductive
   758 datatypes and sets, as well as recursive functions; can be invoked
   759 via 'generate_code' theory section;
   760 
   761 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   762 
   763 * HOL: consolidated and renamed several theories.  In particular:
   764         Ord.thy has been absorbed into HOL.thy
   765         String.thy has been absorbed into List.thy
   766 
   767 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   768 (beware of argument permutation!);
   769 
   770 * HOL: linorder_less_split superseded by linorder_cases;
   771 
   772 * HOL/List: "nodups" renamed to "distinct";
   773 
   774 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   775 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   776   - Ex_def has changed, now need to use some_eq_ex
   777 
   778 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   779 in this (rare) case use:
   780 
   781   delSWrapper "split_all_tac"
   782   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   783 
   784 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   785 MAY FAIL;
   786 
   787 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   788 Isabelle's type classes, ^ on functions and relations has too general
   789 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   790 necessary to attach explicit type constraints;
   791 
   792 * HOL/Relation: the prefix name of the infix "O" has been changed from
   793 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   794 renamed accordingly (eg "compI" -> "rel_compI").
   795 
   796 * HOL: syntax translations now work properly with numerals and records
   797 expressions;
   798 
   799 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   800 of "lam" -- INCOMPATIBILITY;
   801 
   802 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   803 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   804 renamed "Product_Type.unit";
   805 
   806 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   807 
   808 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   809 the "cases" method);
   810 
   811 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   812 Florian Kammüller);
   813 
   814 * HOL/IMP: updated and converted to new-style theory format; several
   815 parts turned into readable document, with proper Isar proof texts and
   816 some explanations (by Gerwin Klein);
   817 
   818 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   819 
   820 * HOL-Hyperreal is now a logic image;
   821 
   822 
   823 *** HOLCF ***
   824 
   825 * Isar: consts/constdefs supports mixfix syntax for continuous
   826 operations;
   827 
   828 * Isar: domain package adapted to new-style theory format, e.g. see
   829 HOLCF/ex/Dnat.thy;
   830 
   831 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   832 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   833 lift.induct_tac, always use UU instead of Undef;
   834 
   835 * HOLCF/IMP: updated and converted to new-style theory;
   836 
   837 
   838 *** ZF ***
   839 
   840 * Isar: proper integration of logic-specific tools and packages,
   841 including theory commands '(co)inductive', '(co)datatype',
   842 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   843 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   844 
   845 * theory Main no longer includes AC; for the Axiom of Choice, base
   846 your theory on Main_ZFC;
   847 
   848 * the integer library now covers quotients and remainders, with many
   849 laws relating division to addition, multiplication, etc.;
   850 
   851 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   852 typeless version of the formalism;
   853 
   854 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   855 format;
   856 
   857 * ZF/Induct: new directory for examples of inductive definitions,
   858 including theory Multiset for multiset orderings; converted to
   859 new-style theory format;
   860 
   861 * ZF: many new theorems about lists, ordinals, etc.;
   862 
   863 
   864 *** General ***
   865 
   866 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   867 variable proof controls level of detail: 0 = no proofs (only oracle
   868 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   869 also ref manual for further ML interfaces;
   870 
   871 * Pure/axclass: removed obsolete ML interface
   872 goal_subclass/goal_arity;
   873 
   874 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   875 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   876 separate tokens, so expressions involving minus need to be spaced
   877 properly;
   878 
   879 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   880 rather than "infixl" or "infixr";
   881 
   882 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   883 sort constraint specifications in type inference; e.g. "x::_::foo"
   884 ensures that the type of "x" is of sort "foo" (but not necessarily a
   885 type variable);
   886 
   887 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   888 control output of nested => (types); the default behavior is
   889 "type_brackets";
   890 
   891 * Pure/syntax: builtin parse translation for "_constify" turns valued
   892 tokens into AST constants;
   893 
   894 * Pure/syntax: prefer later declarations of translations and print
   895 translation functions; potential INCOMPATIBILITY: need to reverse
   896 multiple declarations for same syntax element constant;
   897 
   898 * Pure/show_hyps reset by default (in accordance to existing Isar
   899 practice);
   900 
   901 * Provers/classical: renamed addaltern to addafter, addSaltern to
   902 addSafter;
   903 
   904 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   905 as well;
   906 
   907 * system: tested support for MacOS X; should be able to get Isabelle +
   908 Proof General to work in a plain Terminal after installing Poly/ML
   909 (e.g. from the Isabelle distribution area) and GNU bash alone
   910 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   911 support requires further installations, e.g. from
   912 http://fink.sourceforge.net/);
   913 
   914 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   915 
   916 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   917 of 40 MB), cf. ML_OPTIONS;
   918 
   919 * system: Proof General keywords specification is now part of the
   920 Isabelle distribution (see etc/isar-keywords.el);
   921 
   922 * system: support for persistent Proof General sessions (refrain from
   923 outdating all loaded theories on startup); user may create writable
   924 logic images like this: ``isabelle -q HOL Test'';
   925 
   926 * system: smart selection of Isabelle process versus Isabelle
   927 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   928 run both "isabelle" and "Isabelle" even if file names are badly
   929 damaged (executable inspects the case of the first letter of its own
   930 name); added separate "isabelle-process" and "isabelle-interface";
   931 
   932 * system: refrain from any attempt at filtering input streams; no
   933 longer support ``8bit'' encoding of old isabelle font, instead proper
   934 iso-latin characters may now be used; the related isatools
   935 "symbolinput" and "nonascii" have disappeared as well;
   936 
   937 * system: removed old "xterm" interface (the print modes "xterm" and
   938 "xterm_color" are still available for direct use in a suitable
   939 terminal);
   940 
   941 
   942 
   943 New in Isabelle99-2 (February 2001)
   944 -----------------------------------
   945 
   946 *** Overview of INCOMPATIBILITIES ***
   947 
   948 * HOL: please note that theories in the Library and elsewhere often use the
   949 new-style (Isar) format; to refer to their theorems in an ML script you must
   950 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   951 
   952 * HOL: inductive package no longer splits induction rule aggressively,
   953 but only as far as specified by the introductions given; the old
   954 format may be recovered via ML function complete_split_rule or attribute
   955 'split_rule (complete)';
   956 
   957 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   958 gfp_Tarski to gfp_unfold;
   959 
   960 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   961 
   962 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   963 relation); infix "^^" has been renamed "``"; infix "``" has been
   964 renamed "`"; "univalent" has been renamed "single_valued";
   965 
   966 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   967 operation;
   968 
   969 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   970 
   971 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   972 
   973 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   974 consequence, it is no longer monotonic wrt. the local goal context
   975 (which is now passed through the inductive cases);
   976 
   977 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   978 \<gg> to \<ggreater>;
   979 
   980 
   981 *** Document preparation ***
   982 
   983 * \isabellestyle{NAME} selects version of Isabelle output (currently
   984 available: are "it" for near math-mode best-style output, "sl" for
   985 slanted text style, and "tt" for plain type-writer; if no
   986 \isabellestyle command is given, output is according to slanted
   987 type-writer);
   988 
   989 * support sub/super scripts (for single symbols only), input syntax is
   990 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   991 
   992 * some more standard symbols; see Appendix A of the system manual for
   993 the complete list of symbols defined in isabellesym.sty;
   994 
   995 * improved isabelle style files; more abstract symbol implementation
   996 (should now use \isamath{...} and \isatext{...} in custom symbol
   997 definitions);
   998 
   999 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1000 state; Note that presentation of goal states does not conform to
  1001 actual human-readable proof documents.  Please do not include goal
  1002 states into document output unless you really know what you are doing!
  1003 
  1004 * proper indentation of antiquoted output with proportional LaTeX
  1005 fonts;
  1006 
  1007 * no_document ML operator temporarily disables LaTeX document
  1008 generation;
  1009 
  1010 * isatool unsymbolize tunes sources for plain ASCII communication;
  1011 
  1012 
  1013 *** Isar ***
  1014 
  1015 * Pure: Isar now suffers initial goal statements to contain unbound
  1016 schematic variables (this does not conform to actual readable proof
  1017 documents, due to unpredictable outcome and non-compositional proof
  1018 checking); users who know what they are doing may use schematic goals
  1019 for Prolog-style synthesis of proven results;
  1020 
  1021 * Pure: assumption method (an implicit finishing) now handles actual
  1022 rules as well;
  1023 
  1024 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1025 initial goal, declare "that" only as Pure intro (only for single
  1026 steps); the "that" rule assumption may now be involved in implicit
  1027 finishing, thus ".." becomes a feasible for trivial obtains;
  1028 
  1029 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1030 instance proofs may be performed by "..";
  1031 
  1032 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1033 statements as well;
  1034 
  1035 * Pure: more robust selection of calculational rules;
  1036 
  1037 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1038 rule (as well as the assumption rule);
  1039 
  1040 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1041 lemmas, using the graph browser tool;
  1042 
  1043 * Pure: predict failure of "show" in interactive mode;
  1044 
  1045 * Pure: 'thms_containing' now takes actual terms as arguments;
  1046 
  1047 * HOL: improved method 'induct' --- now handles non-atomic goals
  1048 (potential INCOMPATIBILITY); tuned error handling;
  1049 
  1050 * HOL: cases and induct rules now provide explicit hints about the
  1051 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1052 any remaining facts are inserted into the goal verbatim;
  1053 
  1054 * HOL: local contexts (aka cases) may now contain term bindings as
  1055 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1056 the result to be shown in each case;
  1057 
  1058 * HOL: added 'recdef_tc' command;
  1059 
  1060 * isatool convert assists in eliminating legacy ML scripts;
  1061 
  1062 
  1063 *** HOL ***
  1064 
  1065 * HOL/Library: a collection of generic theories to be used together
  1066 with main HOL; the theory loader path already includes this directory
  1067 by default; the following existing theories have been moved here:
  1068 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1069 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1070 
  1071 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1072 modelling and verification task performed in Isabelle/HOL +
  1073 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1074 
  1075 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1076 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1077 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1078 'domain', this makes the theory consistent with mathematical
  1079 literature;
  1080 
  1081 * HOL basics: added overloaded operations "inverse" and "divide"
  1082 (infix "/"), syntax for generic "abs" operation, generic summation
  1083 operator \<Sum>;
  1084 
  1085 * HOL/typedef: simplified package, provide more useful rules (see also
  1086 HOL/subset.thy);
  1087 
  1088 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1089 now expressed as a proper nested rule (old-style tactic scripts may
  1090 require atomize_strip_tac to cope with non-atomic premises);
  1091 
  1092 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1093 to "split_conv" (old name still available for compatibility);
  1094 
  1095 * HOL: improved concrete syntax for strings (e.g. allows translation
  1096 rules with string literals);
  1097 
  1098 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1099  and Fleuriot's mechanization of analysis, including the transcendental
  1100  functions for the reals;
  1101 
  1102 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1103 
  1104 
  1105 *** CTT ***
  1106 
  1107 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1108 "lam" is displayed as TWO lambda-symbols
  1109 
  1110 * CTT: theory Main now available, containing everything (that is, Bool
  1111 and Arith);
  1112 
  1113 
  1114 *** General ***
  1115 
  1116 * Pure: the Simplifier has been implemented properly as a derived rule
  1117 outside of the actual kernel (at last!); the overall performance
  1118 penalty in practical applications is about 50%, while reliability of
  1119 the Isabelle inference kernel has been greatly improved;
  1120 
  1121 * print modes "brackets" and "no_brackets" control output of nested =>
  1122 (types) and ==> (props); the default behaviour is "brackets";
  1123 
  1124 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1125 as assumptions as well;
  1126 
  1127 * system: support Poly/ML 4.0;
  1128 
  1129 * system: isatool install handles KDE version 1 or 2;
  1130 
  1131 
  1132 
  1133 New in Isabelle99-1 (October 2000)
  1134 ----------------------------------
  1135 
  1136 *** Overview of INCOMPATIBILITIES ***
  1137 
  1138 * HOL: simplification of natural numbers is much changed; to partly
  1139 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1140 issue the following ML commands:
  1141 
  1142   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1143   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1144 
  1145 * HOL: simplification no longer dives into case-expressions; this is
  1146 controlled by "t.weak_case_cong" for each datatype t;
  1147 
  1148 * HOL: nat_less_induct renamed to less_induct;
  1149 
  1150 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1151 fixsome to patch .thy and .ML sources automatically;
  1152 
  1153   select_equality  -> some_equality
  1154   select_eq_Ex     -> some_eq_ex
  1155   selectI2EX       -> someI2_ex
  1156   selectI2         -> someI2
  1157   selectI          -> someI
  1158   select1_equality -> some1_equality
  1159   Eps_sym_eq       -> some_sym_eq_trivial
  1160   Eps_eq           -> some_eq_trivial
  1161 
  1162 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1163 
  1164 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1165 instead);
  1166 
  1167 * HOL: the recursion equations generated by 'recdef' are now called
  1168 f.simps instead of f.rules;
  1169 
  1170 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1171 
  1172 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1173 sometimes be needed;
  1174 
  1175 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1176 
  1177 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1178 
  1179 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1180 product is now "<*>" instead of "Times"; the lexicographic product is
  1181 now "<*lex*>" instead of "**";
  1182 
  1183 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1184 of main HOL, but was unused); better use HOL's datatype package;
  1185 
  1186 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1187 the old syntax may be recovered as follows:
  1188 
  1189   syntax (symbols)
  1190     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1191       (infixl "\\<oplus>" 100)
  1192 
  1193 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1194 
  1195 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1196 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1197 internally;
  1198 
  1199 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1200 changed from A/r to A//r;
  1201 
  1202 * ZF: new treatment of arithmetic (nat & int) may break some old
  1203 proofs;
  1204 
  1205 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1206 rulify -> rule_format, elimify -> elim_format, ...);
  1207 
  1208 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1209 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1210 should have to change intro!! to intro? only); replaced "delrule" by
  1211 "rule del";
  1212 
  1213 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1214 
  1215 * Provers: strengthened force_tac by using new first_best_tac;
  1216 
  1217 * LaTeX document preparation: several changes of isabelle.sty (see
  1218 lib/texinputs);
  1219 
  1220 
  1221 *** Document preparation ***
  1222 
  1223 * formal comments (text blocks etc.) in new-style theories may now
  1224 contain antiquotations of thm/prop/term/typ/text to be presented
  1225 according to latex print mode; concrete syntax is like this:
  1226 @{term[show_types] "f(x) = a + x"};
  1227 
  1228 * isatool mkdir provides easy setup of Isabelle session directories,
  1229 including proper document sources;
  1230 
  1231 * generated LaTeX sources are now deleted after successful run
  1232 (isatool document -c); may retain a copy somewhere else via -D option
  1233 of isatool usedir;
  1234 
  1235 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1236 style files, achieving self-contained LaTeX sources and simplifying
  1237 LaTeX debugging;
  1238 
  1239 * old-style theories now produce (crude) LaTeX output as well;
  1240 
  1241 * browser info session directories are now self-contained (may be put
  1242 on WWW server seperately); improved graphs of nested sessions; removed
  1243 graph for 'all sessions';
  1244 
  1245 * several improvements in isabelle style files; \isabellestyle{it}
  1246 produces fake math mode output; \isamarkupheader is now \section by
  1247 default; see lib/texinputs/isabelle.sty etc.;
  1248 
  1249 
  1250 *** Isar ***
  1251 
  1252 * Isar/Pure: local results and corresponding term bindings are now
  1253 subject to Hindley-Milner polymorphism (similar to ML); this
  1254 accommodates incremental type-inference very nicely;
  1255 
  1256 * Isar/Pure: new derived language element 'obtain' supports
  1257 generalized existence reasoning;
  1258 
  1259 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1260 support accumulation of results, without applying any rules yet;
  1261 useful to collect intermediate results without explicit name
  1262 references, and for use with transitivity rules with more than 2
  1263 premises;
  1264 
  1265 * Isar/Pure: scalable support for case-analysis type proofs: new
  1266 'case' language element refers to local contexts symbolically, as
  1267 produced by certain proof methods; internally, case names are attached
  1268 to theorems as "tags";
  1269 
  1270 * Isar/Pure: theory command 'hide' removes declarations from
  1271 class/type/const name spaces;
  1272 
  1273 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1274 indicate potential overloading;
  1275 
  1276 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1277 
  1278 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1279 "{a,b,c}" instead of {a,b,c};
  1280 
  1281 * Isar/Pure now provides its own version of intro/elim/dest
  1282 attributes; useful for building new logics, but beware of confusion
  1283 with the version in Provers/classical;
  1284 
  1285 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1286 case name 'antecedent';
  1287 
  1288 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1289 to the current context is now done automatically);
  1290 
  1291 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1292 for definining proof methods in ML;
  1293 
  1294 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1295 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1296 most cases, one should have to change intro!! to intro? only);
  1297 replaced "delrule" by "rule del";
  1298 
  1299 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1300 'symmetric' attribute (the latter supercedes [RS sym]);
  1301 
  1302 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1303 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1304 well (including splits);
  1305 
  1306 * Isar/Provers: Simplifier and Classical methods now support all kind
  1307 of modifiers used in the past, including 'cong', 'iff', etc.
  1308 
  1309 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1310 of Simplifier and Classical reasoner);
  1311 
  1312 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1313 now support named cases; major packages (inductive, datatype, primrec,
  1314 recdef) support case names and properly name parameters;
  1315 
  1316 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1317 monotonicity conditions are extracted to be proven at end of
  1318 calculations;
  1319 
  1320 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1321 method anyway;
  1322 
  1323 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1324 split_if split_if_asm; datatype package provides theorems foo.splits =
  1325 foo.split foo.split_asm for each datatype;
  1326 
  1327 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1328 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1329 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1330 use "(cases (simplified))" method in proper proof texts);
  1331 
  1332 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1333 
  1334 * Isar: names of theorems etc. may be natural numbers as well;
  1335 
  1336 * Isar: 'pr' command: optional arguments for goals_limit and
  1337 ProofContext.prems_limit; no longer prints theory contexts, but only
  1338 proof states;
  1339 
  1340 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1341 additional print modes to be specified; e.g. "pr(latex)" will print
  1342 proof state according to the Isabelle LaTeX style;
  1343 
  1344 * Isar: improved support for emulating tactic scripts, including proof
  1345 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1346 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1347 (for HOL datatypes);
  1348 
  1349 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1350 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1351 'proof method scripts' have to be in depth-first order;
  1352 
  1353 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1354 
  1355 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1356 should instead use individual commands for printing items
  1357 (print_commands, print_methods etc.);
  1358 
  1359 * Isar: added 'nothing' --- the empty list of theorems;
  1360 
  1361 
  1362 *** HOL ***
  1363 
  1364 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1365 corresponding virtual machine and a specification of its bytecode
  1366 verifier and a lightweight bytecode verifier, including proofs of
  1367 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1368 Cornelia Pusch (see also the homepage of project Bali at
  1369 http://isabelle.in.tum.de/Bali/);
  1370 
  1371 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1372 Clemens Ballarin;
  1373 
  1374 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1375 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1376 Rasmussen;
  1377 
  1378 * HOL/Lattice: fundamental concepts of lattice theory and order
  1379 structures, including duals, properties of bounds versus algebraic
  1380 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1381 Theorem for complete lattices etc.; may also serve as a demonstration
  1382 for abstract algebraic reasoning using axiomatic type classes, and
  1383 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1384 
  1385 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1386 von Oheimb;
  1387 
  1388 * HOL/IMPP: extension of IMP with local variables and mutually
  1389 recursive procedures, by David von Oheimb;
  1390 
  1391 * HOL/Lambda: converted into new-style theory and document;
  1392 
  1393 * HOL/ex/Multiquote: example of multiple nested quotations and
  1394 anti-quotations -- basically a generalized version of de-Bruijn
  1395 representation; very useful in avoiding lifting of operations;
  1396 
  1397 * HOL/record: added general record equality rule to simpset; fixed
  1398 select-update simplification procedure to handle extended records as
  1399 well; admit "r" as field name;
  1400 
  1401 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1402 other numeric types and also as the identity of groups, rings, etc.;
  1403 
  1404 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1405 Types nat and int belong to this axclass;
  1406 
  1407 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1408    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1409    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1410   two terms #m*u and #n*u are replaced by #(m+n)*u
  1411     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1412   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1413     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1414 
  1415 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1416 powerful prover for predicate logic but knows nothing of clasets; see
  1417 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1418 
  1419 * HOL: new version of "case_tac" subsumes both boolean case split and
  1420 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1421 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1422 
  1423 * HOL: simplification no longer dives into case-expressions: only the
  1424 selector expression is simplified, but not the remaining arms; to
  1425 enable full simplification of case-expressions for datatype t, you may
  1426 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1427 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1428 
  1429 * HOL/recdef: the recursion equations generated by 'recdef' for
  1430 function 'f' are now called f.simps instead of f.rules; if all
  1431 termination conditions are proved automatically, these simplification
  1432 rules are added to the simpset, as in primrec; rules may be named
  1433 individually as well, resulting in a separate list of theorems for
  1434 each equation;
  1435 
  1436 * HOL/While is a new theory that provides a while-combinator. It
  1437 permits the definition of tail-recursive functions without the
  1438 provision of a termination measure. The latter is necessary once the
  1439 invariant proof rule for while is applied.
  1440 
  1441 * HOL: new (overloaded) notation for the set of elements below/above
  1442 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1443 
  1444 * HOL: theorems impI, allI, ballI bound as "strip";
  1445 
  1446 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1447 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1448 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1449 
  1450 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1451 
  1452 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1453 main HOL, but was unused);
  1454 
  1455 * HOL: fewer consts declared as global (e.g. have to refer to
  1456 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1457 
  1458 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1459 in case of overlap with user translations (e.g. judgements over
  1460 tuples); (note that the underlying logical represenation is still
  1461 bogus);
  1462 
  1463 
  1464 *** ZF ***
  1465 
  1466 * ZF: simplification automatically cancels common terms in arithmetic
  1467 expressions over nat and int;
  1468 
  1469 * ZF: new treatment of nat to minimize type-checking: all operators
  1470 coerce their operands to a natural number using the function natify,
  1471 making the algebraic laws unconditional;
  1472 
  1473 * ZF: as above, for int: operators coerce their operands to an integer
  1474 using the function intify;
  1475 
  1476 * ZF: the integer library now contains many of the usual laws for the
  1477 orderings, including $<=, and monotonicity laws for $+ and $*;
  1478 
  1479 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1480 simplification;
  1481 
  1482 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1483 to the simplifier and classical reasoner simultaneously;
  1484 
  1485 
  1486 *** General ***
  1487 
  1488 * Provers: blast_tac now handles actual object-logic rules as
  1489 assumptions; note that auto_tac uses blast_tac internally as well;
  1490 
  1491 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1492 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1493 
  1494 * Provers: delrules now handles destruct rules as well (no longer need
  1495 explicit make_elim);
  1496 
  1497 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1498   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1499 use instead the strong form,
  1500   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1501 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1502 from destruct-rules;
  1503 
  1504 * Provers: Simplifier.easy_setup provides a fast path to basic
  1505 Simplifier setup for new object-logics;
  1506 
  1507 * Pure: AST translation rules no longer require constant head on LHS;
  1508 
  1509 * Pure: improved name spaces: ambiguous output is qualified; support
  1510 for hiding of names;
  1511 
  1512 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1513 XSYMBOL_HOME; no longer need to do manual configuration in most
  1514 situations;
  1515 
  1516 * system: compression of ML heaps images may now be controlled via -c
  1517 option of isabelle and isatool usedir (currently only observed by
  1518 Poly/ML);
  1519 
  1520 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1521 useful for remote X11);
  1522 
  1523 * system: provide TAGS file for Isabelle sources;
  1524 
  1525 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1526 order;
  1527 
  1528 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1529 timing flag supersedes proof_timing and Toplevel.trace;
  1530 
  1531 * ML: new combinators |>> and |>>> for incremental transformations
  1532 with secondary results (e.g. certain theory extensions):
  1533 
  1534 * ML: PureThy.add_defs gets additional argument to indicate potential
  1535 overloading (usually false);
  1536 
  1537 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1538 results;
  1539 
  1540 
  1541 
  1542 New in Isabelle99 (October 1999)
  1543 --------------------------------
  1544 
  1545 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1546 
  1547 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1548 are no longer simplified.  (This allows the simplifier to unfold recursive
  1549 functional programs.)  To restore the old behaviour, declare
  1550 
  1551     Delcongs [if_weak_cong];
  1552 
  1553 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1554 complement;
  1555 
  1556 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1557 
  1558 * HOL/datatype: mutual_induct_tac no longer exists --
  1559   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1560 
  1561 * HOL/typedef: fixed type inference for representing set; type
  1562 arguments now have to occur explicitly on the rhs as type constraints;
  1563 
  1564 * ZF: The con_defs part of an inductive definition may no longer refer
  1565 to constants declared in the same theory;
  1566 
  1567 * HOL, ZF: the function mk_cases, generated by the inductive
  1568 definition package, has lost an argument.  To simplify its result, it
  1569 uses the default simpset instead of a supplied list of theorems.
  1570 
  1571 * HOL/List: the constructors of type list are now Nil and Cons;
  1572 
  1573 * Simplifier: the type of the infix ML functions
  1574         setSSolver addSSolver setSolver addSolver
  1575 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1576 for packaging solvers. A solver is created via
  1577         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1578 where the string argument is only a comment.
  1579 
  1580 
  1581 *** Proof tools ***
  1582 
  1583 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1584 decision procedure for linear arithmetic. Currently it is used for
  1585 types `nat', `int', and `real' in HOL (see below); it can, should and
  1586 will be instantiated for other types and logics as well.
  1587 
  1588 * The simplifier now accepts rewrite rules with flexible heads, eg
  1589      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1590   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1591   matching.
  1592 
  1593 
  1594 *** General ***
  1595 
  1596 * New Isabelle/Isar subsystem provides an alternative to traditional
  1597 tactical theorem proving; together with the ProofGeneral/isar user
  1598 interface it offers an interactive environment for developing human
  1599 readable proof documents (Isar == Intelligible semi-automated
  1600 reasoning); for further information see isatool doc isar-ref,
  1601 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1602 
  1603 * improved and simplified presentation of theories: better HTML markup
  1604 (including colors), graph views in several sizes; isatool usedir now
  1605 provides a proper interface for user theories (via -P option); actual
  1606 document preparation based on (PDF)LaTeX is available as well (for
  1607 new-style theories only); see isatool doc system for more information;
  1608 
  1609 * native support for Proof General, both for classic Isabelle and
  1610 Isabelle/Isar;
  1611 
  1612 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1613 using the graph browser tool;
  1614 
  1615 * Isabelle manuals now also available as PDF;
  1616 
  1617 * theory loader rewritten from scratch (may not be fully
  1618 bug-compatible); old loadpath variable has been replaced by show_path,
  1619 add_path, del_path, reset_path functions; new operations such as
  1620 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1621 isatool doc ref);
  1622 
  1623 * improved isatool install: option -k creates KDE application icon,
  1624 option -p DIR installs standalone binaries;
  1625 
  1626 * added ML_PLATFORM setting (useful for cross-platform installations);
  1627 more robust handling of platform specific ML images for SML/NJ;
  1628 
  1629 * the settings environment is now statically scoped, i.e. it is never
  1630 created again in sub-processes invoked from isabelle, isatool, or
  1631 Isabelle;
  1632 
  1633 * path element specification '~~' refers to '$ISABELLE_HOME';
  1634 
  1635 * in locales, the "assumes" and "defines" parts may be omitted if
  1636 empty;
  1637 
  1638 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1639 long arrows);
  1640 
  1641 * new print_mode "HTML";
  1642 
  1643 * new flag show_tags controls display of tags of theorems (which are
  1644 basically just comments that may be attached by some tools);
  1645 
  1646 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1647 mode and goal output format:
  1648 
  1649 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1650 244c244
  1651 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1652 ---
  1653 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1654 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1655 181c181
  1656 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1657 ---
  1658 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1659 
  1660 * function bind_thms stores lists of theorems (cf. bind_thm);
  1661 
  1662 * new shorthand tactics ftac, eatac, datac, fatac;
  1663 
  1664 * qed (and friends) now accept "" as result name; in that case the
  1665 theorem is not stored, but proper checks and presentation of the
  1666 result still apply;
  1667 
  1668 * theorem database now also indexes constants "Trueprop", "all",
  1669 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1670 
  1671 
  1672 *** HOL ***
  1673 
  1674 ** HOL arithmetic **
  1675 
  1676 * There are now decision procedures for linear arithmetic over nat and
  1677 int:
  1678 
  1679 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1680 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1681 are treated as atomic; subformulae not involving type `nat' or `int'
  1682 are ignored; quantified subformulae are ignored unless they are
  1683 positive universal or negative existential. The tactic has to be
  1684 invoked by hand and can be a little bit slow. In particular, the
  1685 running time is exponential in the number of occurrences of `min' and
  1686 `max', and `-' on `nat'.
  1687 
  1688 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1689 (negated) (in)equalities among the premises and the conclusion into
  1690 account (i.e. no compound formulae) and does not know about `min' and
  1691 `max', and `-' on `nat'. It is fast and is used automatically by the
  1692 simplifier.
  1693 
  1694 NB: At the moment, these decision procedures do not cope with mixed
  1695 nat/int formulae where the two parts interact, such as `m < n ==>
  1696 int(m) < int(n)'.
  1697 
  1698 * HOL/Numeral provides a generic theory of numerals (encoded
  1699 efficiently as bit strings); setup for types nat/int/real is in place;
  1700 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1701 int, existing theories and proof scripts may require a few additional
  1702 type constraints;
  1703 
  1704 * integer division and remainder can now be performed on constant
  1705 arguments;
  1706 
  1707 * many properties of integer multiplication, division and remainder
  1708 are now available;
  1709 
  1710 * An interface to the Stanford Validity Checker (SVC) is available through the
  1711 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1712 are proved automatically.  SVC must be installed separately, and its results
  1713 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1714 invocation of the underlying oracle).  For SVC see
  1715   http://verify.stanford.edu/SVC
  1716 
  1717 * IsaMakefile: the HOL-Real target now builds an actual image;
  1718 
  1719 
  1720 ** HOL misc **
  1721 
  1722 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1723 (in Isabelle/Isar) -- by Gertrud Bauer;
  1724 
  1725 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1726 analysis for assembly languages with subtypes;
  1727 
  1728 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1729 -- avoids syntactic ambiguities and treats state, transition, and
  1730 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1731 changed syntax and (many) tactics;
  1732 
  1733 * HOL/inductive: Now also handles more general introduction rules such
  1734   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1735   theorems are now maintained within the theory (maintained via the
  1736   "mono" attribute);
  1737 
  1738 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1739   (using function types) such as
  1740 
  1741   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1742 
  1743 * HOL/record: record_simproc (part of the default simpset) takes care
  1744 of selectors applied to updated records; record_split_tac is no longer
  1745 part of the default claset; update_defs may now be removed from the
  1746 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1747 
  1748   claset_ref () := claset() addSWrapper record_split_wrapper;
  1749   Delsimprocs [record_simproc]
  1750 
  1751 * HOL/typedef: fixed type inference for representing set; type
  1752 arguments now have to occur explicitly on the rhs as type constraints;
  1753 
  1754 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1755 names rather than an ML expression;
  1756 
  1757 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1758 supplied later.  Program schemes can be defined, such as
  1759     "While B C s = (if B s then While B C (C s) else s)"
  1760 where the well-founded relation can be chosen after B and C have been given.
  1761 
  1762 * HOL/List: the constructors of type list are now Nil and Cons;
  1763 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1764 course, ML tools referring to List.list.op # etc. have to be adapted;
  1765 
  1766 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1767 disabled by default; run isabelle with option -m HOL to get back to
  1768 the original Gordon/HOL-style output;
  1769 
  1770 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1771 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1772 
  1773 * HOL basic syntax simplified (more orthogonal): all variants of
  1774 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1775 Eps operator is provided as well: "SOME x. P[x]";
  1776 
  1777 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1778 
  1779 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1780 thus available for user theories;
  1781 
  1782 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1783 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1784 time;
  1785 
  1786 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1787 several times and then mp;
  1788 
  1789 
  1790 *** LK ***
  1791 
  1792 * the notation <<...>> is now available as a notation for sequences of
  1793 formulas;
  1794 
  1795 * the simplifier is now installed
  1796 
  1797 * the axiom system has been generalized (thanks to Soren Heilmann)
  1798 
  1799 * the classical reasoner now has a default rule database
  1800 
  1801 
  1802 *** ZF ***
  1803 
  1804 * new primrec section allows primitive recursive functions to be given
  1805 directly (as in HOL) over datatypes and the natural numbers;
  1806 
  1807 * new tactics induct_tac and exhaust_tac for induction (or case
  1808 analysis) over datatypes and the natural numbers;
  1809 
  1810 * the datatype declaration of type T now defines the recursor T_rec;
  1811 
  1812 * simplification automatically does freeness reasoning for datatype
  1813 constructors;
  1814 
  1815 * automatic type-inference, with AddTCs command to insert new
  1816 type-checking rules;
  1817 
  1818 * datatype introduction rules are now added as Safe Introduction rules
  1819 to the claset;
  1820 
  1821 * the syntax "if P then x else y" is now available in addition to
  1822 if(P,x,y);
  1823 
  1824 
  1825 *** Internal programming interfaces ***
  1826 
  1827 * tuned simplifier trace output; new flag debug_simp;
  1828 
  1829 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1830 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1831 
  1832 * AxClass.axclass_tac lost the theory argument;
  1833 
  1834 * tuned current_goals_markers semantics: begin / end goal avoids
  1835 printing empty lines;
  1836 
  1837 * removed prs and prs_fn hook, which was broken because it did not
  1838 include \n in its semantics, forcing writeln to add one
  1839 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1840 string -> unit if you really want to output text without newline;
  1841 
  1842 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1843 plain output, interface builders may have to enable 'isabelle_font'
  1844 mode to get Isabelle font glyphs as before;
  1845 
  1846 * refined token_translation interface; INCOMPATIBILITY: output length
  1847 now of type real instead of int;
  1848 
  1849 * theory loader actions may be traced via new ThyInfo.add_hook
  1850 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1851 your own database of information attached to *whole* theories -- as
  1852 opposed to intra-theory data slots offered via TheoryDataFun;
  1853 
  1854 * proper handling of dangling sort hypotheses (at last!);
  1855 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1856 extra sort hypotheses that can be witnessed from the type signature;
  1857 the force_strip_shyps flag is gone, any remaining shyps are simply
  1858 left in the theorem (with a warning issued by strip_shyps_warning);
  1859 
  1860 
  1861 
  1862 New in Isabelle98-1 (October 1998)
  1863 ----------------------------------
  1864 
  1865 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1866 
  1867 * several changes of automated proof tools;
  1868 
  1869 * HOL: major changes to the inductive and datatype packages, including
  1870 some minor incompatibilities of theory syntax;
  1871 
  1872 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1873 called `inj_on';
  1874 
  1875 * HOL: removed duplicate thms in Arith:
  1876   less_imp_add_less  should be replaced by  trans_less_add1
  1877   le_imp_add_le      should be replaced by  trans_le_add1
  1878 
  1879 * HOL: unary minus is now overloaded (new type constraints may be
  1880 required);
  1881 
  1882 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1883 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1884 now taken as an integer constant.
  1885 
  1886 * Pure: ML function 'theory_of' renamed to 'theory';
  1887 
  1888 
  1889 *** Proof tools ***
  1890 
  1891 * Simplifier:
  1892   1. Asm_full_simp_tac is now more aggressive.
  1893      1. It will sometimes reorient premises if that increases their power to
  1894         simplify.
  1895      2. It does no longer proceed strictly from left to right but may also
  1896         rotate premises to achieve further simplification.
  1897      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1898      old Asm_full_simp_tac in that it does not rotate premises.
  1899   2. The simplifier now knows a little bit about nat-arithmetic.
  1900 
  1901 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1902 allows for selected deletion of wrappers, by introduction of names for
  1903 wrapper functionals.  This implies that addbefore, addSbefore,
  1904 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1905 and that adding two tactics with the same name overwrites the first
  1906 one (emitting a warning).
  1907   type wrapper = (int -> tactic) -> (int -> tactic)
  1908   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1909   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1910   delWrapper, delSWrapper: claset *  string            -> claset
  1911   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1912 
  1913 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1914 semantics; addbefore now affects only the unsafe part of step_tac
  1915 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1916 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1917 by Force_tac;
  1918 
  1919 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1920 compWrapper; added safe wrapper (and access functions for it);
  1921 
  1922 * HOL/split_all_tac is now much faster and fails if there is nothing
  1923 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1924 and the names of the automatically generated variables have changed.
  1925 split_all_tac has moved within claset() from unsafe wrappers to safe
  1926 wrappers, which means that !!-bound variables are split much more
  1927 aggressively, and safe_tac and clarify_tac now split such variables.
  1928 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1929 Note: the same holds for record_split_tac, which does the job of
  1930 split_all_tac for record fields.
  1931 
  1932 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1933 permanently to the default simpset using Addsplits just like
  1934 Addsimps. They can be removed via Delsplits just like
  1935 Delsimps. Lower-case versions are also available.
  1936 
  1937 * HOL/Simplifier: The rule split_if is now part of the default
  1938 simpset. This means that the simplifier will eliminate all occurrences
  1939 of if-then-else in the conclusion of a goal. To prevent this, you can
  1940 either remove split_if completely from the default simpset by
  1941 `Delsplits [split_if]' or remove it in a specific call of the
  1942 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1943 other case splitting rules to/from the default simpset: every datatype
  1944 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1945 t is the name of the datatype).
  1946 
  1947 * Classical reasoner / Simplifier combination: new force_tac (and
  1948 derivatives Force_tac, force) combines rewriting and classical
  1949 reasoning (and whatever other tools) similarly to auto_tac, but is
  1950 aimed to solve the given subgoal completely.
  1951 
  1952 
  1953 *** General ***
  1954 
  1955 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1956 and `goalw': the theory is no longer needed as an explicit argument -
  1957 the current theory context is used; assumptions are no longer returned
  1958 at the ML-level unless one of them starts with ==> or !!; it is
  1959 recommended to convert to these new commands using isatool fixgoal
  1960 (backup your sources first!);
  1961 
  1962 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1963 the current theory context, and 'theory' to lookup stored theories;
  1964 
  1965 * new theory section 'locale' for declaring constants, assumptions and
  1966 definitions that have local scope;
  1967 
  1968 * new theory section 'nonterminals' for purely syntactic types;
  1969 
  1970 * new theory section 'setup' for generic ML setup functions
  1971 (e.g. package initialization);
  1972 
  1973 * the distribution now includes Isabelle icons: see
  1974 lib/logo/isabelle-{small,tiny}.xpm;
  1975 
  1976 * isatool install - install binaries with absolute references to
  1977 ISABELLE_HOME/bin;
  1978 
  1979 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1980 
  1981 * print mode 'emacs' reserved for Isamode;
  1982 
  1983 * support multiple print (ast) translations per constant name;
  1984 
  1985 * theorems involving oracles are now printed with a suffixed [!];
  1986 
  1987 
  1988 *** HOL ***
  1989 
  1990 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1991 
  1992 * HOL/inductive package reorganized and improved: now supports mutual
  1993 definitions such as
  1994 
  1995   inductive EVEN ODD
  1996     intrs
  1997       null "0 : EVEN"
  1998       oddI "n : EVEN ==> Suc n : ODD"
  1999       evenI "n : ODD ==> Suc n : EVEN"
  2000 
  2001 new theorem list "elims" contains an elimination rule for each of the
  2002 recursive sets; inductive definitions now handle disjunctive premises
  2003 correctly (also ZF);
  2004 
  2005 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2006 "mutual_induct" no longer exists - the induction rule is always
  2007 contained in "induct";
  2008 
  2009 
  2010 * HOL/datatype package re-implemented and greatly improved: now
  2011 supports mutually recursive datatypes such as
  2012 
  2013   datatype
  2014     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2015             | SUM ('a aexp) ('a aexp)
  2016             | DIFF ('a aexp) ('a aexp)
  2017             | NUM 'a
  2018   and
  2019     'a bexp = LESS ('a aexp) ('a aexp)
  2020             | AND ('a bexp) ('a bexp)
  2021             | OR ('a bexp) ('a bexp)
  2022 
  2023 as well as indirectly recursive datatypes such as
  2024 
  2025   datatype
  2026     ('a, 'b) term = Var 'a
  2027                   | App 'b ((('a, 'b) term) list)
  2028 
  2029 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2030 induction on mutually / indirectly recursive datatypes.
  2031 
  2032 Primrec equations are now stored in theory and can be accessed via
  2033 <function_name>.simps.
  2034 
  2035 INCOMPATIBILITIES:
  2036 
  2037   - Theories using datatypes must now have theory Datatype as an
  2038     ancestor.
  2039   - The specific <typename>.induct_tac no longer exists - use the
  2040     generic induct_tac instead.
  2041   - natE has been renamed to nat.exhaust - use exhaust_tac
  2042     instead of res_inst_tac ... natE. Note that the variable
  2043     names in nat.exhaust differ from the names in natE, this
  2044     may cause some "fragile" proofs to fail.
  2045   - The theorems split_<typename>_case and split_<typename>_case_asm
  2046     have been renamed to <typename>.split and <typename>.split_asm.
  2047   - Since default sorts of type variables are now handled correctly,
  2048     some datatype definitions may have to be annotated with explicit
  2049     sort constraints.
  2050   - Primrec definitions no longer require function name and type
  2051     of recursive argument.
  2052 
  2053 Consider using isatool fixdatatype to adapt your theories and proof
  2054 scripts to the new package (backup your sources first!).
  2055 
  2056 
  2057 * HOL/record package: considerably improved implementation; now
  2058 includes concrete syntax for record types, terms, updates; theorems
  2059 for surjective pairing and splitting !!-bound record variables; proof
  2060 support is as follows:
  2061 
  2062   1) standard conversions (selectors or updates applied to record
  2063 constructor terms) are part of the standard simpset;
  2064 
  2065   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2066 made part of standard simpset and claset via addIffs;
  2067 
  2068   3) a tactic for record field splitting (record_split_tac) is part of
  2069 the standard claset (addSWrapper);
  2070 
  2071 To get a better idea about these rules you may retrieve them via
  2072 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2073 the name of your record type.
  2074 
  2075 The split tactic 3) conceptually simplifies by the following rule:
  2076 
  2077   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2078 
  2079 Thus any record variable that is bound by meta-all will automatically
  2080 blow up into some record constructor term, consequently the
  2081 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2082 solve record problems automatically.
  2083 
  2084 
  2085 * reorganized the main HOL image: HOL/Integ and String loaded by
  2086 default; theory Main includes everything;
  2087 
  2088 * automatic simplification of integer sums and comparisons, using cancellation;
  2089 
  2090 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2091 
  2092 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2093 
  2094 * many new identities for unions, intersections, set difference, etc.;
  2095 
  2096 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2097 called split_if, split_split, split_sum_case and split_nat_case (to go
  2098 with add/delsplits);
  2099 
  2100 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2101 (?x::unit) = (); this is made part of the default simpset, which COULD
  2102 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2103 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2104 unit_abs_eta_conv is added in order to counter the effect of
  2105 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2106 %u.f();
  2107 
  2108 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2109 makes more sense);
  2110 
  2111 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2112   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2113   disjointness reasoning but breaking a few old proofs.
  2114 
  2115 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2116 to 'converse' from 'inverse' (for compatibility with ZF and some
  2117 literature);
  2118 
  2119 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2120 the well-founded relation;
  2121 
  2122 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2123     Compl A.  The "Compl" syntax remains available as input syntax for this
  2124     release ONLY.
  2125 
  2126 * HOL/Update: new theory of function updates:
  2127     f(a:=b) == %x. if x=a then b else f x
  2128 may also be iterated as in f(a:=b,c:=d,...);
  2129 
  2130 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2131 
  2132 * HOL/List:
  2133   - new function list_update written xs[i:=v] that updates the i-th
  2134     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2135   - new function `upt' written [i..j(] which generates the list
  2136     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2137     bound write [i..j], which is a shorthand for [i..j+1(].
  2138   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2139 
  2140 * HOL/Arith:
  2141   - removed 'pred' (predecessor) function;
  2142   - generalized some theorems about n-1;
  2143   - many new laws about "div" and "mod";
  2144   - new laws about greatest common divisors (see theory ex/Primes);
  2145 
  2146 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2147 instead of "inverse";
  2148 
  2149 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2150   of the multiset ordering;
  2151 
  2152 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2153   (not included by default);
  2154 
  2155 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2156 
  2157 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2158   programs, i.e. different program variables may have different types.
  2159 
  2160 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2161   [previously, this check worked only if the rewrite rule was unconditional]
  2162   Now rew can involve either definitions or equalities (either == or =).
  2163 
  2164 
  2165 *** ZF ***
  2166 
  2167 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2168   only the theorems proved on ZF.ML;
  2169 
  2170 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2171   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2172   disjointness reasoning but breaking a few old proofs.
  2173 
  2174 * ZF/Update: new theory of function updates
  2175     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2176   may also be iterated as in f(a:=b,c:=d,...);
  2177 
  2178 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2179 
  2180 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2181   [previously, this check worked only if the rewrite rule was unconditional]
  2182   Now rew can involve either definitions or equalities (either == or =).
  2183 
  2184 * case_tac provided for compatibility with HOL
  2185     (like the old excluded_middle_tac, but with subgoals swapped)
  2186 
  2187 
  2188 *** Internal programming interfaces ***
  2189 
  2190 * Pure: several new basic modules made available for general use, see
  2191 also src/Pure/README;
  2192 
  2193 * improved the theory data mechanism to support encapsulation (data
  2194 kind name replaced by private Object.kind, acting as authorization
  2195 key); new type-safe user interface via functor TheoryDataFun; generic
  2196 print_data function becomes basically useless;
  2197 
  2198 * removed global_names compatibility flag -- all theory declarations
  2199 are qualified by default;
  2200 
  2201 * module Pure/Syntax now offers quote / antiquote translation
  2202 functions (useful for Hoare logic etc. with implicit dependencies);
  2203 see HOL/ex/Antiquote for an example use;
  2204 
  2205 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2206 cterm -> thm;
  2207 
  2208 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2209 subgoal;
  2210 
  2211 * Display.print_goals function moved to Locale.print_goals;
  2212 
  2213 * standard print function for goals supports current_goals_markers
  2214 variable for marking begin of proof, end of proof, start of goal; the
  2215 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2216 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2217 for example;
  2218 
  2219 
  2220 
  2221 New in Isabelle98 (January 1998)
  2222 --------------------------------
  2223 
  2224 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2225 
  2226 * changed lexical syntax of terms / types: dots made part of long
  2227 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2228 
  2229 * simpset (and claset) reference variable replaced by functions
  2230 simpset / simpset_ref;
  2231 
  2232 * no longer supports theory aliases (via merge) and non-trivial
  2233 implicit merge of thms' signatures;
  2234 
  2235 * most internal names of constants changed due to qualified names;
  2236 
  2237 * changed Pure/Sequence interface (see Pure/seq.ML);
  2238 
  2239 
  2240 *** General Changes ***
  2241 
  2242 * hierachically structured name spaces (for consts, types, axms, thms
  2243 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2244 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2245 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2246 long_names for fully qualified output names; NOTE: ML programs
  2247 (special tactics, packages etc.) referring to internal names may have
  2248 to be adapted to cope with fully qualified names; in case of severe
  2249 backward campatibility problems try setting 'global_names' at compile
  2250 time to have enrything declared within a flat name space; one may also
  2251 fine tune name declarations in theories via the 'global' and 'local'
  2252 section;
  2253 
  2254 * reimplemented the implicit simpset and claset using the new anytype
  2255 data filed in signatures; references simpset:simpset ref etc. are
  2256 replaced by functions simpset:unit->simpset and
  2257 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2258 to patch your ML files accordingly;
  2259 
  2260 * HTML output now includes theory graph data for display with Java
  2261 applet or isatool browser; data generated automatically via isatool
  2262 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2263 
  2264 * defs may now be conditional; improved rewrite_goals_tac to handle
  2265 conditional equations;
  2266 
  2267 * defs now admits additional type arguments, using TYPE('a) syntax;
  2268 
  2269 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2270 creates a new theory node; implicit merge of thms' signatures is
  2271 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2272 transfer:theory->thm->thm in (rare) cases;
  2273 
  2274 * improved handling of draft signatures / theories; draft thms (and
  2275 ctyps, cterms) are automatically promoted to real ones;
  2276 
  2277 * slightly changed interfaces for oracles: admit many per theory, named
  2278 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2279 
  2280 * print_goals: optional output of const types (set show_consts and
  2281 show_types);
  2282 
  2283 * improved output of warnings (###) and errors (***);
  2284 
  2285 * subgoal_tac displays a warning if the new subgoal has type variables;
  2286 
  2287 * removed old README and Makefiles;
  2288 
  2289 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2290 
  2291 * removed obsolete init_pps and init_database;
  2292 
  2293 * deleted the obsolete tactical STATE, which was declared by
  2294     fun STATE tacfun st = tacfun st st;
  2295 
  2296 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2297 (which abbreviates $HOME);
  2298 
  2299 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2300 use isatool fixseq to adapt your ML programs (this works for fully
  2301 qualified references to the Sequence structure only!);
  2302 
  2303 * use_thy no longer requires writable current directory; it always
  2304 reloads .ML *and* .thy file, if either one is out of date;
  2305 
  2306 
  2307 *** Classical Reasoner ***
  2308 
  2309 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2310 tactics that use classical reasoning to simplify a subgoal without
  2311 splitting it into several subgoals;
  2312 
  2313 * Safe_tac: like safe_tac but uses the default claset;
  2314 
  2315 
  2316 *** Simplifier ***
  2317 
  2318 * added simplification meta rules:
  2319     (asm_)(full_)simplify: simpset -> thm -> thm;
  2320 
  2321 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2322 logics (again);
  2323 
  2324 * added prems argument to simplification procedures;
  2325 
  2326 * HOL, FOL, ZF: added infix function `addsplits':
  2327   instead of `<simpset> setloop (split_tac <thms>)'
  2328   you can simply write `<simpset> addsplits <thms>'
  2329 
  2330 
  2331 *** Syntax ***
  2332 
  2333 * TYPE('a) syntax for type reflection terms;
  2334 
  2335 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2336 
  2337 * pretty printer: changed order of mixfix annotation preference (again!);
  2338 
  2339 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2340 
  2341 
  2342 *** HOL ***
  2343 
  2344 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2345   with `addloop' of the simplifier to faciliate case splitting in premises.
  2346 
  2347 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2348 
  2349 * HOL/Auth: new protocol proofs including some for the Internet
  2350   protocol TLS;
  2351 
  2352 * HOL/Map: new theory of `maps' a la VDM;
  2353 
  2354 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2355 cancelling out common nat summands from =, <, <= (in)equalities, or
  2356 differences; simplification procedures nat_cancel_factor for
  2357 cancelling common factor from =, <, <= (in)equalities over natural
  2358 sums; nat_cancel contains both kinds of procedures, it is installed by
  2359 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2360 
  2361 * HOL/simplifier: terms of the form
  2362   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2363   are rewritten to
  2364   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2365   and those of the form
  2366   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2367   are rewritten to
  2368   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2369 
  2370 * HOL/datatype
  2371   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2372 
  2373   P(t_case f1 ... fn x) =
  2374      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2375         ...
  2376        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2377      )
  2378 
  2379   and a theorem `split_t_case_asm' of the form
  2380 
  2381   P(t_case f1 ... fn x) =
  2382     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2383         ...
  2384        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2385      )
  2386   which can be added to a simpset via `addsplits'. The existing theorems
  2387   expand_list_case and expand_option_case have been renamed to
  2388   split_list_case and split_option_case.
  2389 
  2390 * HOL/Arithmetic:
  2391   - `pred n' is automatically converted to `n-1'.
  2392     Users are strongly encouraged not to use `pred' any longer,
  2393     because it will disappear altogether at some point.
  2394   - Users are strongly encouraged to write "0 < n" rather than
  2395     "n ~= 0". Theorems and proof tools have been modified towards this
  2396     `standard'.
  2397 
  2398 * HOL/Lists:
  2399   the function "set_of_list" has been renamed "set" (and its theorems too);
  2400   the function "nth" now takes its arguments in the reverse order and
  2401   has acquired the infix notation "!" as in "xs!n".
  2402 
  2403 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2404 
  2405 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2406   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2407 
  2408 * HOL/record: extensible records with schematic structural subtyping
  2409 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2410 still lacks various theorems and concrete record syntax;
  2411 
  2412 
  2413 *** HOLCF ***
  2414 
  2415 * removed "axioms" and "generated by" sections;
  2416 
  2417 * replaced "ops" section by extended "consts" section, which is capable of
  2418   handling the continuous function space "->" directly;
  2419 
  2420 * domain package:
  2421   . proves theorems immediately and stores them in the theory,
  2422   . creates hierachical name space,
  2423   . now uses normal mixfix annotations (instead of cinfix...),
  2424   . minor changes to some names and values (for consistency),
  2425   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2426   . separator between mutual domain defs: changed "," to "and",
  2427   . improved handling of sort constraints;  now they have to
  2428     appear on the left-hand side of the equations only;
  2429 
  2430 * fixed LAM <x,y,zs>.b syntax;
  2431 
  2432 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2433 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2434 
  2435 
  2436 *** FOL and ZF ***
  2437 
  2438 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2439   with `addloop' of the simplifier to faciliate case splitting in premises.
  2440 
  2441 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2442 in HOL, they strip ALL and --> from proved theorems;
  2443 
  2444 
  2445 
  2446 New in Isabelle94-8 (May 1997)
  2447 ------------------------------
  2448 
  2449 *** General Changes ***
  2450 
  2451 * new utilities to build / run / maintain Isabelle etc. (in parts
  2452 still somewhat experimental); old Makefiles etc. still functional;
  2453 
  2454 * new 'Isabelle System Manual';
  2455 
  2456 * INSTALL text, together with ./configure and ./build scripts;
  2457 
  2458 * reimplemented type inference for greater efficiency, better error
  2459 messages and clean internal interface;
  2460 
  2461 * prlim command for dealing with lots of subgoals (an easier way of
  2462 setting goals_limit);
  2463 
  2464 
  2465 *** Syntax ***
  2466 
  2467 * supports alternative (named) syntax tables (parser and pretty
  2468 printer); internal interface is provided by add_modesyntax(_i);
  2469 
  2470 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2471 be used in conjunction with the Isabelle symbol font; uses the
  2472 "symbols" syntax table;
  2473 
  2474 * added token_translation interface (may translate name tokens in
  2475 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2476 the current print_mode); IMPORTANT: user print translation functions
  2477 are responsible for marking newly introduced bounds
  2478 (Syntax.mark_boundT);
  2479 
  2480 * token translations for modes "xterm" and "xterm_color" that display
  2481 names in bold, underline etc. or colors (which requires a color
  2482 version of xterm);
  2483 
  2484 * infixes may now be declared with names independent of their syntax;
  2485 
  2486 * added typed_print_translation (like print_translation, but may
  2487 access type of constant);
  2488 
  2489 
  2490 *** Classical Reasoner ***
  2491 
  2492 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2493 some limitations.  Blast_tac...
  2494   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2495   + ignores elimination rules that don't have the correct format
  2496         (the conclusion MUST be a formula variable)
  2497   + ignores types, which can make HOL proofs fail
  2498   + rules must not require higher-order unification, e.g. apply_type in ZF
  2499     [message "Function Var's argument not a bound variable" relates to this]
  2500   + its proof strategy is more general but can actually be slower
  2501 
  2502 * substitution with equality assumptions no longer permutes other
  2503 assumptions;
  2504 
  2505 * minor changes in semantics of addafter (now called addaltern); renamed
  2506 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2507 (and access functions for it);
  2508 
  2509 * improved combination of classical reasoner and simplifier:
  2510   + functions for handling clasimpsets
  2511   + improvement of addss: now the simplifier is called _after_ the
  2512     safe steps.
  2513   + safe variant of addss called addSss: uses safe simplifications
  2514     _during_ the safe steps. It is more complete as it allows multiple
  2515     instantiations of unknowns (e.g. with slow_tac).
  2516 
  2517 *** Simplifier ***
  2518 
  2519 * added interface for simplification procedures (functions that
  2520 produce *proven* rewrite rules on the fly, depending on current
  2521 redex);
  2522 
  2523 * ordering on terms as parameter (used for ordered rewriting);
  2524 
  2525 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2526 
  2527 * the solver is now split into a safe and an unsafe part.
  2528 This should be invisible for the normal user, except that the
  2529 functions setsolver and addsolver have been renamed to setSolver and
  2530 addSolver; added safe_asm_full_simp_tac;
  2531 
  2532 
  2533 *** HOL ***
  2534 
  2535 * a generic induction tactic `induct_tac' which works for all datatypes and
  2536 also for type `nat';
  2537 
  2538 * a generic case distinction tactic `exhaust_tac' which works for all
  2539 datatypes and also for type `nat';
  2540 
  2541 * each datatype comes with a function `size';
  2542 
  2543 * patterns in case expressions allow tuple patterns as arguments to
  2544 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2545 
  2546 * primrec now also works with type nat;
  2547 
  2548 * recdef: a new declaration form, allows general recursive functions to be
  2549 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2550 
  2551 * the constant for negation has been renamed from "not" to "Not" to
  2552 harmonize with FOL, ZF, LK, etc.;
  2553 
  2554 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2555 infinite lists;
  2556 
  2557 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2558 
  2559 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2560 problems in commutative rings, using axiomatic type classes for + and *;
  2561 
  2562 * more examples in HOL/MiniML and HOL/Auth;
  2563 
  2564 * more default rewrite rules for quantifiers, union/intersection;
  2565 
  2566 * a new constant `arbitrary == @x.False';
  2567 
  2568 * HOLCF/IOA replaces old HOL/IOA;
  2569 
  2570 * HOLCF changes: derived all rules and arities
  2571   + axiomatic type classes instead of classes
  2572   + typedef instead of faking type definitions
  2573   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2574   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2575   + eliminated the types void, one, tr
  2576   + use unit lift and bool lift (with translations) instead of one and tr
  2577   + eliminated blift from Lift3.thy (use Def instead of blift)
  2578   all eliminated rules are derived as theorems --> no visible changes ;
  2579 
  2580 
  2581 *** ZF ***
  2582 
  2583 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2584 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2585 as ZF_cs addSIs [equalityI];
  2586 
  2587 
  2588 
  2589 New in Isabelle94-7 (November 96)
  2590 ---------------------------------
  2591 
  2592 * allowing negative levels (as offsets) in prlev and choplev;
  2593 
  2594 * super-linear speedup for large simplifications;
  2595 
  2596 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2597 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2598 FAIL); can suppress it using the command Delsimps (ex_simps @
  2599 all_simps); De Morgan laws are also now included, by default;
  2600 
  2601 * improved printing of ==>  :  ~:
  2602 
  2603 * new object-logic "Sequents" adds linear logic, while replacing LK
  2604 and Modal (thanks to Sara Kalvala);
  2605 
  2606 * HOL/Auth: correctness proofs for authentication protocols;
  2607 
  2608 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2609 examples on HOL/Auth);
  2610 
  2611 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2612 the rewriter and classical reasoner simultaneously;
  2613 
  2614 * function uresult no longer returns theorems in "standard" format;
  2615 regain previous version by: val uresult = standard o uresult;
  2616 
  2617 
  2618 
  2619 New in Isabelle94-6
  2620 -------------------
  2621 
  2622 * oracles -- these establish an interface between Isabelle and trusted
  2623 external reasoners, which may deliver results as theorems;
  2624 
  2625 * proof objects (in particular record all uses of oracles);
  2626 
  2627 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2628 
  2629 * "constdefs" section in theory files;
  2630 
  2631 * "primrec" section (HOL) no longer requires names;
  2632 
  2633 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2634 
  2635 
  2636 
  2637 New in Isabelle94-5
  2638 -------------------
  2639 
  2640 * reduced space requirements;
  2641 
  2642 * automatic HTML generation from theories;
  2643 
  2644 * theory files no longer require "..." (quotes) around most types;
  2645 
  2646 * new examples, including two proofs of the Church-Rosser theorem;
  2647 
  2648 * non-curried (1994) version of HOL is no longer distributed;
  2649 
  2650 
  2651 
  2652 New in Isabelle94-4
  2653 -------------------
  2654 
  2655 * greatly reduced space requirements;
  2656 
  2657 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2658 
  2659 * searchable theorem database (see the section "Retrieving theorems" on
  2660 page 8 of the Reference Manual);
  2661 
  2662 * new examples, including Grabczewski's monumental case study of the
  2663 Axiom of Choice;
  2664 
  2665 * The previous version of HOL renamed to Old_HOL;
  2666 
  2667 * The new version of HOL (previously called CHOL) uses a curried syntax
  2668 for functions.  Application looks like f a b instead of f(a,b);
  2669 
  2670 * Mutually recursive inductive definitions finally work in HOL;
  2671 
  2672 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2673 translates to the operator "split";
  2674 
  2675 
  2676 
  2677 New in Isabelle94-3
  2678 -------------------
  2679 
  2680 * new infix operator, addss, allowing the classical reasoner to
  2681 perform simplification at each step of its search.  Example:
  2682         fast_tac (cs addss ss)
  2683 
  2684 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2685 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2686 look like (a,b) instead of <a,b>;
  2687 
  2688 * PLEASE NOTE: CHOL will eventually replace HOL!
  2689 
  2690 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2691 It translates to the operator "split".  A new theory of integers is available;
  2692 
  2693 * In ZF, integer numerals now denote two's-complement binary integers.
  2694 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2695 
  2696 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2697 of the Axiom of Choice;
  2698 
  2699 
  2700 
  2701 New in Isabelle94-2
  2702 -------------------
  2703 
  2704 * Significantly faster resolution;
  2705 
  2706 * the different sections in a .thy file can now be mixed and repeated
  2707 freely;
  2708 
  2709 * Database of theorems for FOL, HOL and ZF.  New
  2710 commands including qed, qed_goal and bind_thm store theorems in the database.
  2711 
  2712 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2713 a given theory (thms_of), or find out what theory a theorem was proved in
  2714 (theory_of_thm);
  2715 
  2716 * Bugs fixed in the inductive definition and datatype packages;
  2717 
  2718 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2719 and HOL_dup_cs obsolete;
  2720 
  2721 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2722 have been removed;
  2723 
  2724 * Simpler definition of function space in ZF;
  2725 
  2726 * new results about cardinal and ordinal arithmetic in ZF;
  2727 
  2728 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2729 types;
  2730 
  2731 
  2732 $Id$