NEWS
author wenzelm
Wed Jun 09 18:52:11 2004 +0200 (2004-06-09)
changeset 14897 577f95db94e4
parent 14885 0a840138dcd7
child 14917 b54b11ebe220
permissions -rw-r--r--
* Document preparation: antiquotations provide option 'locale=NAME';
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: considerably improved version of 'constdefs' command.  Now
    10   performs automatic type-inference of declared constants; additional
    11   support for local structure declarations (cf. locales and HOL
    12   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    13   to observe strictly sequential dependencies of definitions within a
    14   single 'constdefs' section; moreover, the declared name needs to be
    15   an identifier.  If all fails, consider to fall back on 'consts' and
    16   'defs' separately.
    17 
    18 * Pure: improved indexed syntax and implicit structures.  First of
    19   all, indexed syntax provides a notational device for subscripted
    20   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    21   expressions.  Secondly, in a local context with structure
    22   declarations, number indexes \<^sub>n or the empty index (default
    23   number 1) refer to a certain fixed variable implicitly; option
    24   show_structs controls printing of implicit structures.  Typical
    25   applications of these concepts involve record types and locales.
    26 
    27 * Pure: clear separation of logical types and nonterminals, where the
    28   latter may only occur in 'syntax' specifications or type
    29   abbreviations.  Before that distinction was only partially
    30   implemented via type class "logic" vs. "{}".  Potential
    31   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    32   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    33   specifications may require further adaption (e.g. Cube/Base.thy).
    34 
    35 * Pure: removed obsolete type class "logic", use the top sort {}
    36   instead.  Note that non-logical types should be declared as
    37   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    38   object-logic specifications.
    39 
    40 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
    41 
    42 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
    43   specified in mixfix annotations as "(00...)".
    44 
    45 * Pure/Syntax: 'advanced' translation functions (parse_translation
    46   etc.) may depend on the signature of the theory context being
    47   presently used for parsing/printing, see also isar-ref manual.
    48 
    49 * Pure: tuned internal renaming of symbolic identifiers -- attach
    50   primes instead of base 26 numbers.
    51 
    52 * Document preparation: antiquotations now provide the option
    53   'locale=NAME' to specify an alternative context used for evaluating
    54   and printing the subsequent argument, as in @{thm [locale=LC]
    55   fold_commute}, for example.  Note that a proof context is escaped to
    56   the enclosing theory context first.
    57 
    58 * ML: all output via channels of writeln/warning/error etc. is now
    59   passed through Output.output.  This gives interface builders a
    60   chance to adapt text encodings in arbitrary manners (say as XML
    61   entities); see the hook provided by Output.add_mode.  On the other
    62   hand, results of Pretty.string_of/str_of (including string_of_term,
    63   string_of_thm etc.) are still 'raw' (containing funny \<^raw...>
    64   symbols), which requires separate application of Output.output
    65   whenever strings are *not* passed on to writeln/warning/error etc.
    66 
    67 
    68 *** HOL ***
    69 
    70 * HOL/record: reimplementation of records. Improved scalability for
    71   records with many fields, avoiding performance problems for type
    72   inference. Records are no longer composed of nested field types, but
    73   of nested extension types. Therefore the record type only grows
    74   linear in the number of extensions and not in the number of fields.
    75   The top-level (users) view on records is preserved.  Potential
    76   INCOMPATIBILITY only in strange cases, where the theory depends on
    77   the old record representation. The type generated for a record is
    78   called <record_name>_ext_type.
    79 
    80 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
    81 
    82   syntax (epsilon)
    83     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
    84 
    85   The symbol \<some> is displayed as the alternative epsilon of LaTeX
    86   and x-symbol; use option '-m epsilon' to get it actually printed.
    87   Moreover, the mathematically important symbolic identifier
    88   \<epsilon> becomes available as variable, constant etc.
    89 
    90 * Simplifier: "record_upd_simproc" for simplification of multiple
    91   record updates enabled by default.  INCOMPATIBILITY: old proofs
    92   break occasionally, since simplification is more powerful by
    93   default.
    94 
    95 
    96 *** HOLCF ***
    97 
    98 * HOLCF: discontinued special version of 'constdefs' (which used to
    99   support continuous functions) in favor of the general Pure one with
   100   full type-inference.
   101 
   102 
   103 *** ZF ***
   104 
   105 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the First
   106   Isomorphism Theorem (on quotienting by the kernel of a homomorphism).
   107 
   108 
   109 
   110 New in Isabelle2004 (April 2004)
   111 --------------------------------
   112 
   113 *** General ***
   114 
   115 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   116   Replaces linorder.ML.
   117 
   118 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   119   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   120   (\<a>...\<z>), are now considered normal letters, and can therefore
   121   be used anywhere where an ASCII letter (a...zA...Z) has until
   122   now. COMPATIBILITY: This obviously changes the parsing of some
   123   terms, especially where a symbol has been used as a binder, say
   124   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   125   as an identifier.  Fix it by inserting a space around former
   126   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   127   existing theory and ML files.
   128 
   129 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   130 
   131 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   132   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   133   a normal (but invisible) letter. For multiple letter subscripts repeat
   134   \<^isub> like this: x\<^isub>1\<^isub>2.
   135 
   136 * Pure: There are now sub-/superscripts that can span more than one
   137   character. Text between \<^bsub> and \<^esub> is set in subscript in
   138   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   139   superscript. The new control characters are not identifier parts.
   140 
   141 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   142   content of "..." to the latex file instead of \isacntrl... . The "..."
   143   may consist of any printable characters excluding the end bracket >.
   144 
   145 * Pure: Using new Isar command "finalconsts" (or the ML functions
   146   Theory.add_finals or Theory.add_finals_i) it is now possible to
   147   declare constants "final", which prevents their being given a definition
   148   later.  It is useful for constants whose behaviour is fixed axiomatically
   149   rather than definitionally, such as the meta-logic connectives.
   150 
   151 * Pure: 'instance' now handles general arities with general sorts
   152   (i.e. intersections of classes),
   153 
   154 * Presentation: generated HTML now uses a CSS style sheet to make layout
   155   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   156   It can be changed to alter the colors/layout of generated pages.
   157 
   158 
   159 *** Isar ***
   160 
   161 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   162   cut_tac, subgoal_tac and thin_tac:
   163   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   164     locales are no longer forced to write Isar proof scripts.
   165     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   166     emulations.
   167   - INCOMPATIBILITY: names of variables to be instantiated may no
   168     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   169     This is consistent with the instantiation attribute "where".
   170 
   171 * Attributes "where" and "of":
   172   - Now take type variables of instantiated theorem into account when reading
   173     the instantiation string.  This fixes a bug that caused instantiated
   174     theorems to have too special types in some circumstances.
   175   - "where" permits explicit instantiations of type variables.
   176 
   177 * Calculation commands "moreover" and "also" no longer interfere with
   178   current facts ("this"), admitting arbitrary combinations with "then"
   179   and derived forms.
   180 
   181 * Locales:
   182   - Goal statements involving the context element "includes" no longer
   183     generate theorems with internal delta predicates (those ending on
   184     "_axioms") in the premise.
   185     Resolve particular premise with <locale>.intro to obtain old form.
   186   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   187     specification and "includes" elements in goal statement.
   188   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   189     [intro?] and [elim?] (respectively) by default.
   190   - Experimental command for instantiation of locales in proof contexts:
   191         instantiate <label>[<attrs>]: <loc>
   192     Instantiates locale <loc> and adds all its theorems to the current context
   193     taking into account their attributes.  Label and attrs are optional
   194     modifiers, like in theorem declarations.  If present, names of
   195     instantiated theorems are qualified with <label>, and the attributes
   196     <attrs> are applied after any attributes these theorems might have already.
   197       If the locale has assumptions, a chained fact of the form
   198     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   199     are derived.  The command does not support old-style locales declared
   200     with "locale (open)".
   201       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   202 
   203 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   204   (Isar) contexts.
   205 
   206 
   207 *** HOL ***
   208 
   209 * Proof import: new image HOL4 contains the imported library from
   210   the HOL4 system with about 2500 theorems. It is imported by
   211   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   212   can be used like any other Isabelle image.  See
   213   HOL/Import/HOL/README for more information.
   214 
   215 * Simplifier:
   216   - Much improved handling of linear and partial orders.
   217     Reasoners for linear and partial orders are set up for type classes
   218     "linorder" and "order" respectively, and are added to the default simpset
   219     as solvers.  This means that the simplifier can build transitivity chains
   220     to solve goals from the assumptions.
   221   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   222     of blast or auto after simplification become unnecessary because the goal
   223     is solved by simplification already.
   224 
   225 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   226     all proved in axiomatic type classes for semirings, rings and fields.
   227 
   228 * Numerics:
   229   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   230     now formalized using the Ring_and_Field theory mentioned above.
   231   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   232     than before, because now they are set up once in a generic manner.
   233   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   234     Look for the general versions in Ring_and_Field (and Power if they concern
   235     exponentiation).
   236 
   237 * Type "rat" of the rational numbers is now available in HOL-Complex.
   238 
   239 * Records:
   240   - Record types are now by default printed with their type abbreviation
   241     instead of the list of all field types. This can be configured via
   242     the reference "print_record_type_abbr".
   243   - Simproc "record_upd_simproc" for simplification of multiple updates added
   244     (not enabled by default).
   245   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   246     EX x. x = sel r to True (not enabled by default).
   247   - Tactic "record_split_simp_tac" to split and simplify records added.
   248 
   249 * 'specification' command added, allowing for definition by
   250   specification.  There is also an 'ax_specification' command that
   251   introduces the new constants axiomatically.
   252 
   253 * arith(_tac) is now able to generate counterexamples for reals as well.
   254 
   255 * HOL-Algebra: new locale "ring" for non-commutative rings.
   256 
   257 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   258   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   259 
   260 * HOL-Matrix: a first theory for matrices in HOL with an application of
   261   matrix theory to linear programming.
   262 
   263 * Unions and Intersections:
   264   The x-symbol output syntax of UN and INT has been changed
   265   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   266   i.e. the index formulae has become a subscript, like in normal math.
   267   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   268   The subscript version is also accepted as input syntax.
   269 
   270 * Unions and Intersections over Intervals:
   271   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   272   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   273   like in normal math, and corresponding versions for < and for intersection.
   274 
   275 * ML: the legacy theory structures Int and List have been removed. They had
   276   conflicted with ML Basis Library structures having the same names.
   277 
   278 * 'refute' command added to search for (finite) countermodels.  Only works
   279   for a fragment of HOL.  The installation of an external SAT solver is
   280   highly recommended.  See "HOL/Refute.thy" for details.
   281 
   282 * 'quickcheck' command: Allows to find counterexamples by evaluating
   283   formulae under an assignment of free variables to random values.
   284   In contrast to 'refute', it can deal with inductive datatypes,
   285   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   286   for examples.
   287 
   288 
   289 *** HOLCF ***
   290 
   291 * Streams now come with concatenation and are part of the HOLCF image
   292 
   293 
   294 
   295 New in Isabelle2003 (May 2003)
   296 ------------------------------
   297 
   298 *** General ***
   299 
   300 * Provers/simplifier:
   301 
   302   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   303     Assumptions are now subject to complete mutual simplification,
   304     not just from left to right. The simplifier now preserves
   305     the order of assumptions.
   306 
   307     Potential INCOMPATIBILITY:
   308 
   309     -- simp sometimes diverges where the old version did
   310        not, e.g. invoking simp on the goal
   311 
   312         [| P (f x); y = x; f x = f y |] ==> Q
   313 
   314        now gives rise to the infinite reduction sequence
   315 
   316         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   317 
   318        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   319        kind of problem.
   320 
   321     -- Tactics combining classical reasoner and simplification (such as auto)
   322        are also affected by this change, because many of them rely on
   323        simp. They may sometimes diverge as well or yield a different numbers
   324        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   325        in case of problems. Sometimes subsequent calls to the classical
   326        reasoner will fail because a preceeding call to the simplifier too
   327        eagerly simplified the goal, e.g. deleted redundant premises.
   328 
   329   - The simplifier trace now shows the names of the applied rewrite rules
   330 
   331   - You can limit the number of recursive invocations of the simplifier
   332     during conditional rewriting (where the simplifie tries to solve the
   333     conditions before applying the rewrite rule):
   334     ML "simp_depth_limit := n"
   335     where n is an integer. Thus you can force termination where previously
   336     the simplifier would diverge.
   337 
   338   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   339 
   340   - No longer aborts on failed congruence proof.  Instead, the
   341     congruence is ignored.
   342 
   343 * Pure: New generic framework for extracting programs from constructive
   344   proofs. See HOL/Extraction.thy for an example instantiation, as well
   345   as HOL/Extraction for some case studies.
   346 
   347 * Pure: The main goal of the proof state is no longer shown by default, only
   348 the subgoals. This behaviour is controlled by a new flag.
   349    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   350 (ML: Proof.show_main_goal).
   351 
   352 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   353 rules whose conclusion matches subgoal 1:
   354       PG menu: Isabelle/Isar -> Show me -> matching rules
   355 The rules are ordered by how closely they match the subgoal.
   356 In particular, rules that solve a subgoal outright are displayed first
   357 (or rather last, the way they are printed).
   358 (ML: ProofGeneral.print_intros())
   359 
   360 * Pure: New flag trace_unify_fail causes unification to print
   361 diagnostic information (PG: in trace buffer) when it fails. This is
   362 useful for figuring out why single step proofs like rule, erule or
   363 assumption failed.
   364 
   365 * Pure: Locale specifications now produce predicate definitions
   366 according to the body of text (covering assumptions modulo local
   367 definitions); predicate "loc_axioms" covers newly introduced text,
   368 while "loc" is cumulative wrt. all included locale expressions; the
   369 latter view is presented only on export into the global theory
   370 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   371 on the old view without predicates;
   372 
   373 * Pure: predefined locales "var" and "struct" are useful for sharing
   374 parameters (as in CASL, for example); just specify something like
   375 ``var x + var y + struct M'' as import;
   376 
   377 * Pure: improved thms_containing: proper indexing of facts instead of
   378 raw theorems; check validity of results wrt. current name space;
   379 include local facts of proof configuration (also covers active
   380 locales), cover fixed variables in index; may use "_" in term
   381 specification; an optional limit for the number of printed facts may
   382 be given (the default is 40);
   383 
   384 * Pure: disallow duplicate fact bindings within new-style theory files
   385 (batch-mode only);
   386 
   387 * Provers: improved induct method: assumptions introduced by case
   388 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   389 the goal statement); "foo" still refers to all facts collectively;
   390 
   391 * Provers: the function blast.overloaded has been removed: all constants
   392 are regarded as potentially overloaded, which improves robustness in exchange
   393 for slight decrease in efficiency;
   394 
   395 * Provers/linorder: New generic prover for transitivity reasoning over
   396 linear orders.  Note: this prover is not efficient!
   397 
   398 * Isar: preview of problems to finish 'show' now produce an error
   399 rather than just a warning (in interactive mode);
   400 
   401 
   402 *** HOL ***
   403 
   404 * arith(_tac)
   405 
   406  - Produces a counter example if it cannot prove a goal.
   407    Note that the counter example may be spurious if the goal is not a formula
   408    of quantifier-free linear arithmetic.
   409    In ProofGeneral the counter example appears in the trace buffer.
   410 
   411  - Knows about div k and mod k where k is a numeral of type nat or int.
   412 
   413  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   414    linear arithmetic fails. This takes account of quantifiers and divisibility.
   415    Presburger arithmetic can also be called explicitly via presburger(_tac).
   416 
   417 * simp's arithmetic capabilities have been enhanced a bit: it now
   418 takes ~= in premises into account (by performing a case split);
   419 
   420 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   421 are distributed over a sum of terms;
   422 
   423 * New tactic "trans_tac" and method "trans" instantiate
   424 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   425 "<=", "<" and "=").
   426 
   427 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   428 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   429 
   430 * 'typedef' command has new option "open" to suppress the set
   431 definition;
   432 
   433 * functions Min and Max on finite sets have been introduced (theory
   434 Finite_Set);
   435 
   436 * attribute [symmetric] now works for relations as well; it turns
   437 (x,y) : R^-1 into (y,x) : R, and vice versa;
   438 
   439 * induct over a !!-quantified statement (say !!x1..xn):
   440   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   441 
   442 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   443 %x. None. Warning: empty_def now refers to the previously hidden definition
   444 of the empty set.
   445 
   446 * Algebra: formalization of classical algebra.  Intended as base for
   447 any algebraic development in Isabelle.  Currently covers group theory
   448 (up to Sylow's theorem) and ring theory (Universal Property of
   449 Univariate Polynomials).  Contributions welcome;
   450 
   451 * GroupTheory: deleted, since its material has been moved to Algebra;
   452 
   453 * Complex: new directory of the complex numbers with numeric constants,
   454 nonstandard complex numbers, and some complex analysis, standard and
   455 nonstandard (Jacques Fleuriot);
   456 
   457 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   458 
   459 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   460 Fleuriot);
   461 
   462 * Real/HahnBanach: updated and adapted to locales;
   463 
   464 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   465 Gray and Kramer);
   466 
   467 * UNITY: added the Meier-Sanders theory of progress sets;
   468 
   469 * MicroJava: bytecode verifier and lightweight bytecode verifier
   470 as abstract algorithms, instantiated to the JVM;
   471 
   472 * Bali: Java source language formalization. Type system, operational
   473 semantics, axiomatic semantics. Supported language features:
   474 classes, interfaces, objects,virtual methods, static methods,
   475 static/instance fields, arrays, access modifiers, definite
   476 assignment, exceptions.
   477 
   478 
   479 *** ZF ***
   480 
   481 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   482 universe, etc.);
   483 
   484 * Main ZF: virtually all theories converted to new-style format;
   485 
   486 
   487 *** ML ***
   488 
   489 * Pure: Tactic.prove provides sane interface for internal proofs;
   490 omits the infamous "standard" operation, so this is more appropriate
   491 than prove_goalw_cterm in many situations (e.g. in simprocs);
   492 
   493 * Pure: improved error reporting of simprocs;
   494 
   495 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   496 up simprocs;
   497 
   498 
   499 *** Document preparation ***
   500 
   501 * uses \par instead of \\ for line breaks in theory text. This may
   502 shift some page breaks in large documents. To get the old behaviour
   503 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   504 
   505 * minimized dependencies of isabelle.sty and isabellesym.sty on
   506 other packages
   507 
   508 * \<euro> now needs package babel/greek instead of marvosym (which
   509 broke \Rightarrow)
   510 
   511 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   512 textcomp package)
   513 
   514 
   515 
   516 New in Isabelle2002 (March 2002)
   517 --------------------------------
   518 
   519 *** Document preparation ***
   520 
   521 * greatly simplified document preparation setup, including more
   522 graceful interpretation of isatool usedir -i/-d/-D options, and more
   523 instructive isatool mkdir; users should basically be able to get
   524 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   525 users may run a separate document processing stage manually like this:
   526 "isatool usedir -D output HOL Test && isatool document Test/output";
   527 
   528 * theory dependency graph may now be incorporated into documents;
   529 isatool usedir -g true will produce session_graph.eps/.pdf for use
   530 with \includegraphics of LaTeX;
   531 
   532 * proper spacing of consecutive markup elements, especially text
   533 blocks after section headings;
   534 
   535 * support bold style (for single symbols only), input syntax is like
   536 this: "\<^bold>\<alpha>" or "\<^bold>A";
   537 
   538 * \<bullet> is now output as bold \cdot by default, which looks much
   539 better in printed text;
   540 
   541 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   542 note that these symbols are currently unavailable in Proof General /
   543 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   544 
   545 * isatool latex no longer depends on changed TEXINPUTS, instead
   546 isatool document copies the Isabelle style files to the target
   547 location;
   548 
   549 
   550 *** Isar ***
   551 
   552 * Pure/Provers: improved proof by cases and induction;
   553   - 'case' command admits impromptu naming of parameters (such as
   554     "case (Suc n)");
   555   - 'induct' method divinates rule instantiation from the inductive
   556     claim; no longer requires excessive ?P bindings for proper
   557     instantiation of cases;
   558   - 'induct' method properly enumerates all possibilities of set/type
   559     rules; as a consequence facts may be also passed through *type*
   560     rules without further ado;
   561   - 'induct' method now derives symbolic cases from the *rulified*
   562     rule (before it used to rulify cases stemming from the internal
   563     atomized version); this means that the context of a non-atomic
   564     statement becomes is included in the hypothesis, avoiding the
   565     slightly cumbersome show "PROP ?case" form;
   566   - 'induct' may now use elim-style induction rules without chaining
   567     facts, using ``missing'' premises from the goal state; this allows
   568     rules stemming from inductive sets to be applied in unstructured
   569     scripts, while still benefitting from proper handling of non-atomic
   570     statements; NB: major inductive premises need to be put first, all
   571     the rest of the goal is passed through the induction;
   572   - 'induct' proper support for mutual induction involving non-atomic
   573     rule statements (uses the new concept of simultaneous goals, see
   574     below);
   575   - append all possible rule selections, but only use the first
   576     success (no backtracking);
   577   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   578   - undeclared rule case names default to numbers 1, 2, 3, ...;
   579   - added 'print_induct_rules' (covered by help item in recent Proof
   580     General versions);
   581   - moved induct/cases attributes to Pure, methods to Provers;
   582   - generic method setup instantiated for FOL and HOL;
   583 
   584 * Pure: support multiple simultaneous goal statements, for example
   585 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   586 meta-level mechanism, this acts as if several individual goals had
   587 been stated separately; in particular common proof methods need to be
   588 repeated in order to cover all claims; note that a single elimination
   589 step is *not* sufficient to establish the two conjunctions, so this
   590 fails:
   591 
   592   assume "A & B" then have A and B ..   (*".." fails*)
   593 
   594 better use "obtain" in situations as above; alternative refer to
   595 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   596 
   597 * Pure: proper integration with ``locales''; unlike the original
   598 version by Florian Kammüller, Isar locales package high-level proof
   599 contexts rather than raw logical ones (e.g. we admit to include
   600 attributes everywhere); operations on locales include merge and
   601 rename; support for implicit arguments (``structures''); simultaneous
   602 type-inference over imports and text; see also HOL/ex/Locales.thy for
   603 some examples;
   604 
   605 * Pure: the following commands have been ``localized'', supporting a
   606 target locale specification "(in name)": 'lemma', 'theorem',
   607 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   608 stored both within the locale and at the theory level (exported and
   609 qualified by the locale name);
   610 
   611 * Pure: theory goals may now be specified in ``long'' form, with
   612 ad-hoc contexts consisting of arbitrary locale elements. for example
   613 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   614 definitions may be given, too); the result is a meta-level rule with
   615 the context elements being discharged in the obvious way;
   616 
   617 * Pure: new proof command 'using' allows to augment currently used
   618 facts after a goal statement ('using' is syntactically analogous to
   619 'apply', but acts on the goal's facts only); this allows chained facts
   620 to be separated into parts given before and after a claim, as in
   621 ``from a and b have C using d and e <proof>'';
   622 
   623 * Pure: renamed "antecedent" case to "rule_context";
   624 
   625 * Pure: new 'judgment' command records explicit information about the
   626 object-logic embedding (used by several tools internally); no longer
   627 use hard-wired "Trueprop";
   628 
   629 * Pure: added 'corollary' command;
   630 
   631 * Pure: fixed 'token_translation' command;
   632 
   633 * Pure: removed obsolete 'exported' attribute;
   634 
   635 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   636 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   637 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   638 
   639 * Pure: method 'atomize' presents local goal premises as object-level
   640 statements (atomic meta-level propositions); setup controlled via
   641 rewrite rules declarations of 'atomize' attribute; example
   642 application: 'induct' method with proper rule statements in improper
   643 proof *scripts*;
   644 
   645 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   646 now consider the syntactic context of assumptions, giving a better
   647 chance to get type-inference of the arguments right (this is
   648 especially important for locales);
   649 
   650 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   651 mode;
   652 
   653 * Pure/obtain: the formal conclusion "thesis", being marked as
   654 ``internal'', may no longer be reference directly in the text;
   655 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   656 situations;
   657 
   658 * Pure: generic 'sym' attribute which declares a rule both as pure
   659 'elim?' and for the 'symmetric' operation;
   660 
   661 * Pure: marginal comments ``--'' may now occur just anywhere in the
   662 text; the fixed correlation with particular command syntax has been
   663 discontinued;
   664 
   665 * Pure: new method 'rules' is particularly well-suited for proof
   666 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   667 but often produces more compact proof terms with less detours;
   668 
   669 * Pure/Provers/classical: simplified integration with pure rule
   670 attributes and methods; the classical "intro?/elim?/dest?"
   671 declarations coincide with the pure ones; the "rule" method no longer
   672 includes classically swapped intros; "intro" and "elim" methods no
   673 longer pick rules from the context; also got rid of ML declarations
   674 AddXIs/AddXEs/AddXDs; all of this has some potential for
   675 INCOMPATIBILITY;
   676 
   677 * Provers/classical: attribute 'swapped' produces classical inversions
   678 of introduction rules;
   679 
   680 * Provers/simplifier: 'simplified' attribute may refer to explicit
   681 rules instead of full simplifier context; 'iff' attribute handles
   682 conditional rules;
   683 
   684 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   685 
   686 * HOL: 'recdef' now fails on unfinished automated proofs, use
   687 "(permissive)" option to recover old behavior;
   688 
   689 * HOL: 'inductive' no longer features separate (collective) attributes
   690 for 'intros' (was found too confusing);
   691 
   692 * HOL: properly declared induction rules less_induct and
   693 wf_induct_rule;
   694 
   695 
   696 *** HOL ***
   697 
   698 * HOL: moved over to sane numeral syntax; the new policy is as
   699 follows:
   700 
   701   - 0 and 1 are polymorphic constants, which are defined on any
   702   numeric type (nat, int, real etc.);
   703 
   704   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   705   binary representation internally;
   706 
   707   - type nat has special constructor Suc, and generally prefers Suc 0
   708   over 1::nat and Suc (Suc 0) over 2::nat;
   709 
   710 This change may cause significant problems of INCOMPATIBILITY; here
   711 are some hints on converting existing sources:
   712 
   713   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   714   entities, so expressions involving "-" (unary or binary minus) need
   715   to be spaced properly;
   716 
   717   - existing occurrences of "1" may need to be constraint "1::nat" or
   718   even replaced by Suc 0; similar for old "2";
   719 
   720   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   721 
   722   - remove all special provisions on numerals in proofs;
   723 
   724 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   725 representation (depends on bin_arith_simps in the default context);
   726 
   727 * HOL: symbolic syntax for x^2 (numeral 2);
   728 
   729 * HOL: the class of all HOL types is now called "type" rather than
   730 "term"; INCOMPATIBILITY, need to adapt references to this type class
   731 in axclass/classes, instance/arities, and (usually rare) occurrences
   732 in typings (of consts etc.); internally the class is called
   733 "HOL.type", ML programs should refer to HOLogic.typeS;
   734 
   735 * HOL/record package improvements:
   736   - new derived operations "fields" to build a partial record section,
   737     "extend" to promote a fixed record to a record scheme, and
   738     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   739     declared as simp by default;
   740   - shared operations ("more", "fields", etc.) now need to be always
   741     qualified) --- potential INCOMPATIBILITY;
   742   - removed "make_scheme" operations (use "make" with "extend") --
   743     INCOMPATIBILITY;
   744   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   745   - provides cases/induct rules for use with corresponding Isar
   746     methods (for concrete records, record schemes, concrete more
   747     parts, and schematic more parts -- in that order);
   748   - internal definitions directly based on a light-weight abstract
   749     theory of product types over typedef rather than datatype;
   750 
   751 * HOL: generic code generator for generating executable ML code from
   752 specifications; specific support for HOL constructs such as inductive
   753 datatypes and sets, as well as recursive functions; can be invoked
   754 via 'generate_code' theory section;
   755 
   756 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   757 
   758 * HOL: consolidated and renamed several theories.  In particular:
   759         Ord.thy has been absorbed into HOL.thy
   760         String.thy has been absorbed into List.thy
   761 
   762 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   763 (beware of argument permutation!);
   764 
   765 * HOL: linorder_less_split superseded by linorder_cases;
   766 
   767 * HOL/List: "nodups" renamed to "distinct";
   768 
   769 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   770 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   771   - Ex_def has changed, now need to use some_eq_ex
   772 
   773 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   774 in this (rare) case use:
   775 
   776   delSWrapper "split_all_tac"
   777   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   778 
   779 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   780 MAY FAIL;
   781 
   782 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   783 Isabelle's type classes, ^ on functions and relations has too general
   784 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   785 necessary to attach explicit type constraints;
   786 
   787 * HOL/Relation: the prefix name of the infix "O" has been changed from
   788 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   789 renamed accordingly (eg "compI" -> "rel_compI").
   790 
   791 * HOL: syntax translations now work properly with numerals and records
   792 expressions;
   793 
   794 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   795 of "lam" -- INCOMPATIBILITY;
   796 
   797 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   798 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   799 renamed "Product_Type.unit";
   800 
   801 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   802 
   803 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   804 the "cases" method);
   805 
   806 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   807 Florian Kammüller);
   808 
   809 * HOL/IMP: updated and converted to new-style theory format; several
   810 parts turned into readable document, with proper Isar proof texts and
   811 some explanations (by Gerwin Klein);
   812 
   813 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   814 
   815 * HOL-Hyperreal is now a logic image;
   816 
   817 
   818 *** HOLCF ***
   819 
   820 * Isar: consts/constdefs supports mixfix syntax for continuous
   821 operations;
   822 
   823 * Isar: domain package adapted to new-style theory format, e.g. see
   824 HOLCF/ex/Dnat.thy;
   825 
   826 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   827 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   828 lift.induct_tac, always use UU instead of Undef;
   829 
   830 * HOLCF/IMP: updated and converted to new-style theory;
   831 
   832 
   833 *** ZF ***
   834 
   835 * Isar: proper integration of logic-specific tools and packages,
   836 including theory commands '(co)inductive', '(co)datatype',
   837 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   838 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   839 
   840 * theory Main no longer includes AC; for the Axiom of Choice, base
   841 your theory on Main_ZFC;
   842 
   843 * the integer library now covers quotients and remainders, with many
   844 laws relating division to addition, multiplication, etc.;
   845 
   846 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   847 typeless version of the formalism;
   848 
   849 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   850 format;
   851 
   852 * ZF/Induct: new directory for examples of inductive definitions,
   853 including theory Multiset for multiset orderings; converted to
   854 new-style theory format;
   855 
   856 * ZF: many new theorems about lists, ordinals, etc.;
   857 
   858 
   859 *** General ***
   860 
   861 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   862 variable proof controls level of detail: 0 = no proofs (only oracle
   863 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   864 also ref manual for further ML interfaces;
   865 
   866 * Pure/axclass: removed obsolete ML interface
   867 goal_subclass/goal_arity;
   868 
   869 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   870 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   871 separate tokens, so expressions involving minus need to be spaced
   872 properly;
   873 
   874 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   875 rather than "infixl" or "infixr";
   876 
   877 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   878 sort constraint specifications in type inference; e.g. "x::_::foo"
   879 ensures that the type of "x" is of sort "foo" (but not necessarily a
   880 type variable);
   881 
   882 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   883 control output of nested => (types); the default behavior is
   884 "type_brackets";
   885 
   886 * Pure/syntax: builtin parse translation for "_constify" turns valued
   887 tokens into AST constants;
   888 
   889 * Pure/syntax: prefer later declarations of translations and print
   890 translation functions; potential INCOMPATIBILITY: need to reverse
   891 multiple declarations for same syntax element constant;
   892 
   893 * Pure/show_hyps reset by default (in accordance to existing Isar
   894 practice);
   895 
   896 * Provers/classical: renamed addaltern to addafter, addSaltern to
   897 addSafter;
   898 
   899 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   900 as well;
   901 
   902 * system: tested support for MacOS X; should be able to get Isabelle +
   903 Proof General to work in a plain Terminal after installing Poly/ML
   904 (e.g. from the Isabelle distribution area) and GNU bash alone
   905 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   906 support requires further installations, e.g. from
   907 http://fink.sourceforge.net/);
   908 
   909 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   910 
   911 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   912 of 40 MB), cf. ML_OPTIONS;
   913 
   914 * system: Proof General keywords specification is now part of the
   915 Isabelle distribution (see etc/isar-keywords.el);
   916 
   917 * system: support for persistent Proof General sessions (refrain from
   918 outdating all loaded theories on startup); user may create writable
   919 logic images like this: ``isabelle -q HOL Test'';
   920 
   921 * system: smart selection of Isabelle process versus Isabelle
   922 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   923 run both "isabelle" and "Isabelle" even if file names are badly
   924 damaged (executable inspects the case of the first letter of its own
   925 name); added separate "isabelle-process" and "isabelle-interface";
   926 
   927 * system: refrain from any attempt at filtering input streams; no
   928 longer support ``8bit'' encoding of old isabelle font, instead proper
   929 iso-latin characters may now be used; the related isatools
   930 "symbolinput" and "nonascii" have disappeared as well;
   931 
   932 * system: removed old "xterm" interface (the print modes "xterm" and
   933 "xterm_color" are still available for direct use in a suitable
   934 terminal);
   935 
   936 
   937 
   938 New in Isabelle99-2 (February 2001)
   939 -----------------------------------
   940 
   941 *** Overview of INCOMPATIBILITIES ***
   942 
   943 * HOL: please note that theories in the Library and elsewhere often use the
   944 new-style (Isar) format; to refer to their theorems in an ML script you must
   945 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   946 
   947 * HOL: inductive package no longer splits induction rule aggressively,
   948 but only as far as specified by the introductions given; the old
   949 format may be recovered via ML function complete_split_rule or attribute
   950 'split_rule (complete)';
   951 
   952 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   953 gfp_Tarski to gfp_unfold;
   954 
   955 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   956 
   957 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   958 relation); infix "^^" has been renamed "``"; infix "``" has been
   959 renamed "`"; "univalent" has been renamed "single_valued";
   960 
   961 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   962 operation;
   963 
   964 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   965 
   966 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   967 
   968 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   969 consequence, it is no longer monotonic wrt. the local goal context
   970 (which is now passed through the inductive cases);
   971 
   972 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   973 \<gg> to \<ggreater>;
   974 
   975 
   976 *** Document preparation ***
   977 
   978 * \isabellestyle{NAME} selects version of Isabelle output (currently
   979 available: are "it" for near math-mode best-style output, "sl" for
   980 slanted text style, and "tt" for plain type-writer; if no
   981 \isabellestyle command is given, output is according to slanted
   982 type-writer);
   983 
   984 * support sub/super scripts (for single symbols only), input syntax is
   985 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   986 
   987 * some more standard symbols; see Appendix A of the system manual for
   988 the complete list of symbols defined in isabellesym.sty;
   989 
   990 * improved isabelle style files; more abstract symbol implementation
   991 (should now use \isamath{...} and \isatext{...} in custom symbol
   992 definitions);
   993 
   994 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   995 state; Note that presentation of goal states does not conform to
   996 actual human-readable proof documents.  Please do not include goal
   997 states into document output unless you really know what you are doing!
   998 
   999 * proper indentation of antiquoted output with proportional LaTeX
  1000 fonts;
  1001 
  1002 * no_document ML operator temporarily disables LaTeX document
  1003 generation;
  1004 
  1005 * isatool unsymbolize tunes sources for plain ASCII communication;
  1006 
  1007 
  1008 *** Isar ***
  1009 
  1010 * Pure: Isar now suffers initial goal statements to contain unbound
  1011 schematic variables (this does not conform to actual readable proof
  1012 documents, due to unpredictable outcome and non-compositional proof
  1013 checking); users who know what they are doing may use schematic goals
  1014 for Prolog-style synthesis of proven results;
  1015 
  1016 * Pure: assumption method (an implicit finishing) now handles actual
  1017 rules as well;
  1018 
  1019 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1020 initial goal, declare "that" only as Pure intro (only for single
  1021 steps); the "that" rule assumption may now be involved in implicit
  1022 finishing, thus ".." becomes a feasible for trivial obtains;
  1023 
  1024 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1025 instance proofs may be performed by "..";
  1026 
  1027 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1028 statements as well;
  1029 
  1030 * Pure: more robust selection of calculational rules;
  1031 
  1032 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1033 rule (as well as the assumption rule);
  1034 
  1035 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1036 lemmas, using the graph browser tool;
  1037 
  1038 * Pure: predict failure of "show" in interactive mode;
  1039 
  1040 * Pure: 'thms_containing' now takes actual terms as arguments;
  1041 
  1042 * HOL: improved method 'induct' --- now handles non-atomic goals
  1043 (potential INCOMPATIBILITY); tuned error handling;
  1044 
  1045 * HOL: cases and induct rules now provide explicit hints about the
  1046 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1047 any remaining facts are inserted into the goal verbatim;
  1048 
  1049 * HOL: local contexts (aka cases) may now contain term bindings as
  1050 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1051 the result to be shown in each case;
  1052 
  1053 * HOL: added 'recdef_tc' command;
  1054 
  1055 * isatool convert assists in eliminating legacy ML scripts;
  1056 
  1057 
  1058 *** HOL ***
  1059 
  1060 * HOL/Library: a collection of generic theories to be used together
  1061 with main HOL; the theory loader path already includes this directory
  1062 by default; the following existing theories have been moved here:
  1063 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1064 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1065 
  1066 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1067 modelling and verification task performed in Isabelle/HOL +
  1068 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1069 
  1070 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1071 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1072 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1073 'domain', this makes the theory consistent with mathematical
  1074 literature;
  1075 
  1076 * HOL basics: added overloaded operations "inverse" and "divide"
  1077 (infix "/"), syntax for generic "abs" operation, generic summation
  1078 operator \<Sum>;
  1079 
  1080 * HOL/typedef: simplified package, provide more useful rules (see also
  1081 HOL/subset.thy);
  1082 
  1083 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1084 now expressed as a proper nested rule (old-style tactic scripts may
  1085 require atomize_strip_tac to cope with non-atomic premises);
  1086 
  1087 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1088 to "split_conv" (old name still available for compatibility);
  1089 
  1090 * HOL: improved concrete syntax for strings (e.g. allows translation
  1091 rules with string literals);
  1092 
  1093 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1094  and Fleuriot's mechanization of analysis, including the transcendental
  1095  functions for the reals;
  1096 
  1097 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1098 
  1099 
  1100 *** CTT ***
  1101 
  1102 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1103 "lam" is displayed as TWO lambda-symbols
  1104 
  1105 * CTT: theory Main now available, containing everything (that is, Bool
  1106 and Arith);
  1107 
  1108 
  1109 *** General ***
  1110 
  1111 * Pure: the Simplifier has been implemented properly as a derived rule
  1112 outside of the actual kernel (at last!); the overall performance
  1113 penalty in practical applications is about 50%, while reliability of
  1114 the Isabelle inference kernel has been greatly improved;
  1115 
  1116 * print modes "brackets" and "no_brackets" control output of nested =>
  1117 (types) and ==> (props); the default behaviour is "brackets";
  1118 
  1119 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1120 as assumptions as well;
  1121 
  1122 * system: support Poly/ML 4.0;
  1123 
  1124 * system: isatool install handles KDE version 1 or 2;
  1125 
  1126 
  1127 
  1128 New in Isabelle99-1 (October 2000)
  1129 ----------------------------------
  1130 
  1131 *** Overview of INCOMPATIBILITIES ***
  1132 
  1133 * HOL: simplification of natural numbers is much changed; to partly
  1134 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1135 issue the following ML commands:
  1136 
  1137   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1138   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1139 
  1140 * HOL: simplification no longer dives into case-expressions; this is
  1141 controlled by "t.weak_case_cong" for each datatype t;
  1142 
  1143 * HOL: nat_less_induct renamed to less_induct;
  1144 
  1145 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1146 fixsome to patch .thy and .ML sources automatically;
  1147 
  1148   select_equality  -> some_equality
  1149   select_eq_Ex     -> some_eq_ex
  1150   selectI2EX       -> someI2_ex
  1151   selectI2         -> someI2
  1152   selectI          -> someI
  1153   select1_equality -> some1_equality
  1154   Eps_sym_eq       -> some_sym_eq_trivial
  1155   Eps_eq           -> some_eq_trivial
  1156 
  1157 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1158 
  1159 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1160 instead);
  1161 
  1162 * HOL: the recursion equations generated by 'recdef' are now called
  1163 f.simps instead of f.rules;
  1164 
  1165 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1166 
  1167 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1168 sometimes be needed;
  1169 
  1170 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1171 
  1172 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1173 
  1174 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1175 product is now "<*>" instead of "Times"; the lexicographic product is
  1176 now "<*lex*>" instead of "**";
  1177 
  1178 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1179 of main HOL, but was unused); better use HOL's datatype package;
  1180 
  1181 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1182 the old syntax may be recovered as follows:
  1183 
  1184   syntax (symbols)
  1185     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1186       (infixl "\\<oplus>" 100)
  1187 
  1188 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1189 
  1190 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1191 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1192 internally;
  1193 
  1194 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1195 changed from A/r to A//r;
  1196 
  1197 * ZF: new treatment of arithmetic (nat & int) may break some old
  1198 proofs;
  1199 
  1200 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1201 rulify -> rule_format, elimify -> elim_format, ...);
  1202 
  1203 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1204 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1205 should have to change intro!! to intro? only); replaced "delrule" by
  1206 "rule del";
  1207 
  1208 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1209 
  1210 * Provers: strengthened force_tac by using new first_best_tac;
  1211 
  1212 * LaTeX document preparation: several changes of isabelle.sty (see
  1213 lib/texinputs);
  1214 
  1215 
  1216 *** Document preparation ***
  1217 
  1218 * formal comments (text blocks etc.) in new-style theories may now
  1219 contain antiquotations of thm/prop/term/typ/text to be presented
  1220 according to latex print mode; concrete syntax is like this:
  1221 @{term[show_types] "f(x) = a + x"};
  1222 
  1223 * isatool mkdir provides easy setup of Isabelle session directories,
  1224 including proper document sources;
  1225 
  1226 * generated LaTeX sources are now deleted after successful run
  1227 (isatool document -c); may retain a copy somewhere else via -D option
  1228 of isatool usedir;
  1229 
  1230 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1231 style files, achieving self-contained LaTeX sources and simplifying
  1232 LaTeX debugging;
  1233 
  1234 * old-style theories now produce (crude) LaTeX output as well;
  1235 
  1236 * browser info session directories are now self-contained (may be put
  1237 on WWW server seperately); improved graphs of nested sessions; removed
  1238 graph for 'all sessions';
  1239 
  1240 * several improvements in isabelle style files; \isabellestyle{it}
  1241 produces fake math mode output; \isamarkupheader is now \section by
  1242 default; see lib/texinputs/isabelle.sty etc.;
  1243 
  1244 
  1245 *** Isar ***
  1246 
  1247 * Isar/Pure: local results and corresponding term bindings are now
  1248 subject to Hindley-Milner polymorphism (similar to ML); this
  1249 accommodates incremental type-inference very nicely;
  1250 
  1251 * Isar/Pure: new derived language element 'obtain' supports
  1252 generalized existence reasoning;
  1253 
  1254 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1255 support accumulation of results, without applying any rules yet;
  1256 useful to collect intermediate results without explicit name
  1257 references, and for use with transitivity rules with more than 2
  1258 premises;
  1259 
  1260 * Isar/Pure: scalable support for case-analysis type proofs: new
  1261 'case' language element refers to local contexts symbolically, as
  1262 produced by certain proof methods; internally, case names are attached
  1263 to theorems as "tags";
  1264 
  1265 * Isar/Pure: theory command 'hide' removes declarations from
  1266 class/type/const name spaces;
  1267 
  1268 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1269 indicate potential overloading;
  1270 
  1271 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1272 
  1273 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1274 "{a,b,c}" instead of {a,b,c};
  1275 
  1276 * Isar/Pure now provides its own version of intro/elim/dest
  1277 attributes; useful for building new logics, but beware of confusion
  1278 with the version in Provers/classical;
  1279 
  1280 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1281 case name 'antecedent';
  1282 
  1283 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1284 to the current context is now done automatically);
  1285 
  1286 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1287 for definining proof methods in ML;
  1288 
  1289 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1290 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1291 most cases, one should have to change intro!! to intro? only);
  1292 replaced "delrule" by "rule del";
  1293 
  1294 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1295 'symmetric' attribute (the latter supercedes [RS sym]);
  1296 
  1297 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1298 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1299 well (including splits);
  1300 
  1301 * Isar/Provers: Simplifier and Classical methods now support all kind
  1302 of modifiers used in the past, including 'cong', 'iff', etc.
  1303 
  1304 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1305 of Simplifier and Classical reasoner);
  1306 
  1307 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1308 now support named cases; major packages (inductive, datatype, primrec,
  1309 recdef) support case names and properly name parameters;
  1310 
  1311 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1312 monotonicity conditions are extracted to be proven at end of
  1313 calculations;
  1314 
  1315 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1316 method anyway;
  1317 
  1318 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1319 split_if split_if_asm; datatype package provides theorems foo.splits =
  1320 foo.split foo.split_asm for each datatype;
  1321 
  1322 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1323 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1324 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1325 use "(cases (simplified))" method in proper proof texts);
  1326 
  1327 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1328 
  1329 * Isar: names of theorems etc. may be natural numbers as well;
  1330 
  1331 * Isar: 'pr' command: optional arguments for goals_limit and
  1332 ProofContext.prems_limit; no longer prints theory contexts, but only
  1333 proof states;
  1334 
  1335 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1336 additional print modes to be specified; e.g. "pr(latex)" will print
  1337 proof state according to the Isabelle LaTeX style;
  1338 
  1339 * Isar: improved support for emulating tactic scripts, including proof
  1340 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1341 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1342 (for HOL datatypes);
  1343 
  1344 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1345 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1346 'proof method scripts' have to be in depth-first order;
  1347 
  1348 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1349 
  1350 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1351 should instead use individual commands for printing items
  1352 (print_commands, print_methods etc.);
  1353 
  1354 * Isar: added 'nothing' --- the empty list of theorems;
  1355 
  1356 
  1357 *** HOL ***
  1358 
  1359 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1360 corresponding virtual machine and a specification of its bytecode
  1361 verifier and a lightweight bytecode verifier, including proofs of
  1362 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1363 Cornelia Pusch (see also the homepage of project Bali at
  1364 http://isabelle.in.tum.de/Bali/);
  1365 
  1366 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1367 Clemens Ballarin;
  1368 
  1369 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1370 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1371 Rasmussen;
  1372 
  1373 * HOL/Lattice: fundamental concepts of lattice theory and order
  1374 structures, including duals, properties of bounds versus algebraic
  1375 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1376 Theorem for complete lattices etc.; may also serve as a demonstration
  1377 for abstract algebraic reasoning using axiomatic type classes, and
  1378 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1379 
  1380 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1381 von Oheimb;
  1382 
  1383 * HOL/IMPP: extension of IMP with local variables and mutually
  1384 recursive procedures, by David von Oheimb;
  1385 
  1386 * HOL/Lambda: converted into new-style theory and document;
  1387 
  1388 * HOL/ex/Multiquote: example of multiple nested quotations and
  1389 anti-quotations -- basically a generalized version of de-Bruijn
  1390 representation; very useful in avoiding lifting of operations;
  1391 
  1392 * HOL/record: added general record equality rule to simpset; fixed
  1393 select-update simplification procedure to handle extended records as
  1394 well; admit "r" as field name;
  1395 
  1396 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1397 other numeric types and also as the identity of groups, rings, etc.;
  1398 
  1399 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1400 Types nat and int belong to this axclass;
  1401 
  1402 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1403    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1404    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1405   two terms #m*u and #n*u are replaced by #(m+n)*u
  1406     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1407   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1408     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1409 
  1410 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1411 powerful prover for predicate logic but knows nothing of clasets; see
  1412 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1413 
  1414 * HOL: new version of "case_tac" subsumes both boolean case split and
  1415 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1416 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1417 
  1418 * HOL: simplification no longer dives into case-expressions: only the
  1419 selector expression is simplified, but not the remaining arms; to
  1420 enable full simplification of case-expressions for datatype t, you may
  1421 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1422 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1423 
  1424 * HOL/recdef: the recursion equations generated by 'recdef' for
  1425 function 'f' are now called f.simps instead of f.rules; if all
  1426 termination conditions are proved automatically, these simplification
  1427 rules are added to the simpset, as in primrec; rules may be named
  1428 individually as well, resulting in a separate list of theorems for
  1429 each equation;
  1430 
  1431 * HOL/While is a new theory that provides a while-combinator. It
  1432 permits the definition of tail-recursive functions without the
  1433 provision of a termination measure. The latter is necessary once the
  1434 invariant proof rule for while is applied.
  1435 
  1436 * HOL: new (overloaded) notation for the set of elements below/above
  1437 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1438 
  1439 * HOL: theorems impI, allI, ballI bound as "strip";
  1440 
  1441 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1442 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1443 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1444 
  1445 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1446 
  1447 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1448 main HOL, but was unused);
  1449 
  1450 * HOL: fewer consts declared as global (e.g. have to refer to
  1451 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1452 
  1453 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1454 in case of overlap with user translations (e.g. judgements over
  1455 tuples); (note that the underlying logical represenation is still
  1456 bogus);
  1457 
  1458 
  1459 *** ZF ***
  1460 
  1461 * ZF: simplification automatically cancels common terms in arithmetic
  1462 expressions over nat and int;
  1463 
  1464 * ZF: new treatment of nat to minimize type-checking: all operators
  1465 coerce their operands to a natural number using the function natify,
  1466 making the algebraic laws unconditional;
  1467 
  1468 * ZF: as above, for int: operators coerce their operands to an integer
  1469 using the function intify;
  1470 
  1471 * ZF: the integer library now contains many of the usual laws for the
  1472 orderings, including $<=, and monotonicity laws for $+ and $*;
  1473 
  1474 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1475 simplification;
  1476 
  1477 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1478 to the simplifier and classical reasoner simultaneously;
  1479 
  1480 
  1481 *** General ***
  1482 
  1483 * Provers: blast_tac now handles actual object-logic rules as
  1484 assumptions; note that auto_tac uses blast_tac internally as well;
  1485 
  1486 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1487 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1488 
  1489 * Provers: delrules now handles destruct rules as well (no longer need
  1490 explicit make_elim);
  1491 
  1492 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1493   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1494 use instead the strong form,
  1495   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1496 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1497 from destruct-rules;
  1498 
  1499 * Provers: Simplifier.easy_setup provides a fast path to basic
  1500 Simplifier setup for new object-logics;
  1501 
  1502 * Pure: AST translation rules no longer require constant head on LHS;
  1503 
  1504 * Pure: improved name spaces: ambiguous output is qualified; support
  1505 for hiding of names;
  1506 
  1507 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1508 XSYMBOL_HOME; no longer need to do manual configuration in most
  1509 situations;
  1510 
  1511 * system: compression of ML heaps images may now be controlled via -c
  1512 option of isabelle and isatool usedir (currently only observed by
  1513 Poly/ML);
  1514 
  1515 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1516 useful for remote X11);
  1517 
  1518 * system: provide TAGS file for Isabelle sources;
  1519 
  1520 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1521 order;
  1522 
  1523 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1524 timing flag supersedes proof_timing and Toplevel.trace;
  1525 
  1526 * ML: new combinators |>> and |>>> for incremental transformations
  1527 with secondary results (e.g. certain theory extensions):
  1528 
  1529 * ML: PureThy.add_defs gets additional argument to indicate potential
  1530 overloading (usually false);
  1531 
  1532 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1533 results;
  1534 
  1535 
  1536 
  1537 New in Isabelle99 (October 1999)
  1538 --------------------------------
  1539 
  1540 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1541 
  1542 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1543 are no longer simplified.  (This allows the simplifier to unfold recursive
  1544 functional programs.)  To restore the old behaviour, declare
  1545 
  1546     Delcongs [if_weak_cong];
  1547 
  1548 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1549 complement;
  1550 
  1551 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1552 
  1553 * HOL/datatype: mutual_induct_tac no longer exists --
  1554   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1555 
  1556 * HOL/typedef: fixed type inference for representing set; type
  1557 arguments now have to occur explicitly on the rhs as type constraints;
  1558 
  1559 * ZF: The con_defs part of an inductive definition may no longer refer
  1560 to constants declared in the same theory;
  1561 
  1562 * HOL, ZF: the function mk_cases, generated by the inductive
  1563 definition package, has lost an argument.  To simplify its result, it
  1564 uses the default simpset instead of a supplied list of theorems.
  1565 
  1566 * HOL/List: the constructors of type list are now Nil and Cons;
  1567 
  1568 * Simplifier: the type of the infix ML functions
  1569         setSSolver addSSolver setSolver addSolver
  1570 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1571 for packaging solvers. A solver is created via
  1572         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1573 where the string argument is only a comment.
  1574 
  1575 
  1576 *** Proof tools ***
  1577 
  1578 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1579 decision procedure for linear arithmetic. Currently it is used for
  1580 types `nat', `int', and `real' in HOL (see below); it can, should and
  1581 will be instantiated for other types and logics as well.
  1582 
  1583 * The simplifier now accepts rewrite rules with flexible heads, eg
  1584      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1585   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1586   matching.
  1587 
  1588 
  1589 *** General ***
  1590 
  1591 * New Isabelle/Isar subsystem provides an alternative to traditional
  1592 tactical theorem proving; together with the ProofGeneral/isar user
  1593 interface it offers an interactive environment for developing human
  1594 readable proof documents (Isar == Intelligible semi-automated
  1595 reasoning); for further information see isatool doc isar-ref,
  1596 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1597 
  1598 * improved and simplified presentation of theories: better HTML markup
  1599 (including colors), graph views in several sizes; isatool usedir now
  1600 provides a proper interface for user theories (via -P option); actual
  1601 document preparation based on (PDF)LaTeX is available as well (for
  1602 new-style theories only); see isatool doc system for more information;
  1603 
  1604 * native support for Proof General, both for classic Isabelle and
  1605 Isabelle/Isar;
  1606 
  1607 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1608 using the graph browser tool;
  1609 
  1610 * Isabelle manuals now also available as PDF;
  1611 
  1612 * theory loader rewritten from scratch (may not be fully
  1613 bug-compatible); old loadpath variable has been replaced by show_path,
  1614 add_path, del_path, reset_path functions; new operations such as
  1615 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1616 isatool doc ref);
  1617 
  1618 * improved isatool install: option -k creates KDE application icon,
  1619 option -p DIR installs standalone binaries;
  1620 
  1621 * added ML_PLATFORM setting (useful for cross-platform installations);
  1622 more robust handling of platform specific ML images for SML/NJ;
  1623 
  1624 * the settings environment is now statically scoped, i.e. it is never
  1625 created again in sub-processes invoked from isabelle, isatool, or
  1626 Isabelle;
  1627 
  1628 * path element specification '~~' refers to '$ISABELLE_HOME';
  1629 
  1630 * in locales, the "assumes" and "defines" parts may be omitted if
  1631 empty;
  1632 
  1633 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1634 long arrows);
  1635 
  1636 * new print_mode "HTML";
  1637 
  1638 * new flag show_tags controls display of tags of theorems (which are
  1639 basically just comments that may be attached by some tools);
  1640 
  1641 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1642 mode and goal output format:
  1643 
  1644 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1645 244c244
  1646 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1647 ---
  1648 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1649 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1650 181c181
  1651 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1652 ---
  1653 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1654 
  1655 * function bind_thms stores lists of theorems (cf. bind_thm);
  1656 
  1657 * new shorthand tactics ftac, eatac, datac, fatac;
  1658 
  1659 * qed (and friends) now accept "" as result name; in that case the
  1660 theorem is not stored, but proper checks and presentation of the
  1661 result still apply;
  1662 
  1663 * theorem database now also indexes constants "Trueprop", "all",
  1664 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1665 
  1666 
  1667 *** HOL ***
  1668 
  1669 ** HOL arithmetic **
  1670 
  1671 * There are now decision procedures for linear arithmetic over nat and
  1672 int:
  1673 
  1674 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1675 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1676 are treated as atomic; subformulae not involving type `nat' or `int'
  1677 are ignored; quantified subformulae are ignored unless they are
  1678 positive universal or negative existential. The tactic has to be
  1679 invoked by hand and can be a little bit slow. In particular, the
  1680 running time is exponential in the number of occurrences of `min' and
  1681 `max', and `-' on `nat'.
  1682 
  1683 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1684 (negated) (in)equalities among the premises and the conclusion into
  1685 account (i.e. no compound formulae) and does not know about `min' and
  1686 `max', and `-' on `nat'. It is fast and is used automatically by the
  1687 simplifier.
  1688 
  1689 NB: At the moment, these decision procedures do not cope with mixed
  1690 nat/int formulae where the two parts interact, such as `m < n ==>
  1691 int(m) < int(n)'.
  1692 
  1693 * HOL/Numeral provides a generic theory of numerals (encoded
  1694 efficiently as bit strings); setup for types nat/int/real is in place;
  1695 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1696 int, existing theories and proof scripts may require a few additional
  1697 type constraints;
  1698 
  1699 * integer division and remainder can now be performed on constant
  1700 arguments;
  1701 
  1702 * many properties of integer multiplication, division and remainder
  1703 are now available;
  1704 
  1705 * An interface to the Stanford Validity Checker (SVC) is available through the
  1706 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1707 are proved automatically.  SVC must be installed separately, and its results
  1708 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1709 invocation of the underlying oracle).  For SVC see
  1710   http://verify.stanford.edu/SVC
  1711 
  1712 * IsaMakefile: the HOL-Real target now builds an actual image;
  1713 
  1714 
  1715 ** HOL misc **
  1716 
  1717 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1718 (in Isabelle/Isar) -- by Gertrud Bauer;
  1719 
  1720 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1721 analysis for assembly languages with subtypes;
  1722 
  1723 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1724 -- avoids syntactic ambiguities and treats state, transition, and
  1725 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1726 changed syntax and (many) tactics;
  1727 
  1728 * HOL/inductive: Now also handles more general introduction rules such
  1729   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1730   theorems are now maintained within the theory (maintained via the
  1731   "mono" attribute);
  1732 
  1733 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1734   (using function types) such as
  1735 
  1736   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1737 
  1738 * HOL/record: record_simproc (part of the default simpset) takes care
  1739 of selectors applied to updated records; record_split_tac is no longer
  1740 part of the default claset; update_defs may now be removed from the
  1741 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1742 
  1743   claset_ref () := claset() addSWrapper record_split_wrapper;
  1744   Delsimprocs [record_simproc]
  1745 
  1746 * HOL/typedef: fixed type inference for representing set; type
  1747 arguments now have to occur explicitly on the rhs as type constraints;
  1748 
  1749 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1750 names rather than an ML expression;
  1751 
  1752 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1753 supplied later.  Program schemes can be defined, such as
  1754     "While B C s = (if B s then While B C (C s) else s)"
  1755 where the well-founded relation can be chosen after B and C have been given.
  1756 
  1757 * HOL/List: the constructors of type list are now Nil and Cons;
  1758 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1759 course, ML tools referring to List.list.op # etc. have to be adapted;
  1760 
  1761 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1762 disabled by default; run isabelle with option -m HOL to get back to
  1763 the original Gordon/HOL-style output;
  1764 
  1765 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1766 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1767 
  1768 * HOL basic syntax simplified (more orthogonal): all variants of
  1769 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1770 Eps operator is provided as well: "SOME x. P[x]";
  1771 
  1772 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1773 
  1774 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1775 thus available for user theories;
  1776 
  1777 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1778 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1779 time;
  1780 
  1781 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1782 several times and then mp;
  1783 
  1784 
  1785 *** LK ***
  1786 
  1787 * the notation <<...>> is now available as a notation for sequences of
  1788 formulas;
  1789 
  1790 * the simplifier is now installed
  1791 
  1792 * the axiom system has been generalized (thanks to Soren Heilmann)
  1793 
  1794 * the classical reasoner now has a default rule database
  1795 
  1796 
  1797 *** ZF ***
  1798 
  1799 * new primrec section allows primitive recursive functions to be given
  1800 directly (as in HOL) over datatypes and the natural numbers;
  1801 
  1802 * new tactics induct_tac and exhaust_tac for induction (or case
  1803 analysis) over datatypes and the natural numbers;
  1804 
  1805 * the datatype declaration of type T now defines the recursor T_rec;
  1806 
  1807 * simplification automatically does freeness reasoning for datatype
  1808 constructors;
  1809 
  1810 * automatic type-inference, with AddTCs command to insert new
  1811 type-checking rules;
  1812 
  1813 * datatype introduction rules are now added as Safe Introduction rules
  1814 to the claset;
  1815 
  1816 * the syntax "if P then x else y" is now available in addition to
  1817 if(P,x,y);
  1818 
  1819 
  1820 *** Internal programming interfaces ***
  1821 
  1822 * tuned simplifier trace output; new flag debug_simp;
  1823 
  1824 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1825 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1826 
  1827 * AxClass.axclass_tac lost the theory argument;
  1828 
  1829 * tuned current_goals_markers semantics: begin / end goal avoids
  1830 printing empty lines;
  1831 
  1832 * removed prs and prs_fn hook, which was broken because it did not
  1833 include \n in its semantics, forcing writeln to add one
  1834 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1835 string -> unit if you really want to output text without newline;
  1836 
  1837 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1838 plain output, interface builders may have to enable 'isabelle_font'
  1839 mode to get Isabelle font glyphs as before;
  1840 
  1841 * refined token_translation interface; INCOMPATIBILITY: output length
  1842 now of type real instead of int;
  1843 
  1844 * theory loader actions may be traced via new ThyInfo.add_hook
  1845 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1846 your own database of information attached to *whole* theories -- as
  1847 opposed to intra-theory data slots offered via TheoryDataFun;
  1848 
  1849 * proper handling of dangling sort hypotheses (at last!);
  1850 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1851 extra sort hypotheses that can be witnessed from the type signature;
  1852 the force_strip_shyps flag is gone, any remaining shyps are simply
  1853 left in the theorem (with a warning issued by strip_shyps_warning);
  1854 
  1855 
  1856 
  1857 New in Isabelle98-1 (October 1998)
  1858 ----------------------------------
  1859 
  1860 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1861 
  1862 * several changes of automated proof tools;
  1863 
  1864 * HOL: major changes to the inductive and datatype packages, including
  1865 some minor incompatibilities of theory syntax;
  1866 
  1867 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1868 called `inj_on';
  1869 
  1870 * HOL: removed duplicate thms in Arith:
  1871   less_imp_add_less  should be replaced by  trans_less_add1
  1872   le_imp_add_le      should be replaced by  trans_le_add1
  1873 
  1874 * HOL: unary minus is now overloaded (new type constraints may be
  1875 required);
  1876 
  1877 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1878 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1879 now taken as an integer constant.
  1880 
  1881 * Pure: ML function 'theory_of' renamed to 'theory';
  1882 
  1883 
  1884 *** Proof tools ***
  1885 
  1886 * Simplifier:
  1887   1. Asm_full_simp_tac is now more aggressive.
  1888      1. It will sometimes reorient premises if that increases their power to
  1889         simplify.
  1890      2. It does no longer proceed strictly from left to right but may also
  1891         rotate premises to achieve further simplification.
  1892      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1893      old Asm_full_simp_tac in that it does not rotate premises.
  1894   2. The simplifier now knows a little bit about nat-arithmetic.
  1895 
  1896 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1897 allows for selected deletion of wrappers, by introduction of names for
  1898 wrapper functionals.  This implies that addbefore, addSbefore,
  1899 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1900 and that adding two tactics with the same name overwrites the first
  1901 one (emitting a warning).
  1902   type wrapper = (int -> tactic) -> (int -> tactic)
  1903   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1904   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1905   delWrapper, delSWrapper: claset *  string            -> claset
  1906   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1907 
  1908 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1909 semantics; addbefore now affects only the unsafe part of step_tac
  1910 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1911 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1912 by Force_tac;
  1913 
  1914 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1915 compWrapper; added safe wrapper (and access functions for it);
  1916 
  1917 * HOL/split_all_tac is now much faster and fails if there is nothing
  1918 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1919 and the names of the automatically generated variables have changed.
  1920 split_all_tac has moved within claset() from unsafe wrappers to safe
  1921 wrappers, which means that !!-bound variables are split much more
  1922 aggressively, and safe_tac and clarify_tac now split such variables.
  1923 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1924 Note: the same holds for record_split_tac, which does the job of
  1925 split_all_tac for record fields.
  1926 
  1927 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1928 permanently to the default simpset using Addsplits just like
  1929 Addsimps. They can be removed via Delsplits just like
  1930 Delsimps. Lower-case versions are also available.
  1931 
  1932 * HOL/Simplifier: The rule split_if is now part of the default
  1933 simpset. This means that the simplifier will eliminate all occurrences
  1934 of if-then-else in the conclusion of a goal. To prevent this, you can
  1935 either remove split_if completely from the default simpset by
  1936 `Delsplits [split_if]' or remove it in a specific call of the
  1937 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1938 other case splitting rules to/from the default simpset: every datatype
  1939 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1940 t is the name of the datatype).
  1941 
  1942 * Classical reasoner / Simplifier combination: new force_tac (and
  1943 derivatives Force_tac, force) combines rewriting and classical
  1944 reasoning (and whatever other tools) similarly to auto_tac, but is
  1945 aimed to solve the given subgoal completely.
  1946 
  1947 
  1948 *** General ***
  1949 
  1950 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1951 and `goalw': the theory is no longer needed as an explicit argument -
  1952 the current theory context is used; assumptions are no longer returned
  1953 at the ML-level unless one of them starts with ==> or !!; it is
  1954 recommended to convert to these new commands using isatool fixgoal
  1955 (backup your sources first!);
  1956 
  1957 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1958 the current theory context, and 'theory' to lookup stored theories;
  1959 
  1960 * new theory section 'locale' for declaring constants, assumptions and
  1961 definitions that have local scope;
  1962 
  1963 * new theory section 'nonterminals' for purely syntactic types;
  1964 
  1965 * new theory section 'setup' for generic ML setup functions
  1966 (e.g. package initialization);
  1967 
  1968 * the distribution now includes Isabelle icons: see
  1969 lib/logo/isabelle-{small,tiny}.xpm;
  1970 
  1971 * isatool install - install binaries with absolute references to
  1972 ISABELLE_HOME/bin;
  1973 
  1974 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1975 
  1976 * print mode 'emacs' reserved for Isamode;
  1977 
  1978 * support multiple print (ast) translations per constant name;
  1979 
  1980 * theorems involving oracles are now printed with a suffixed [!];
  1981 
  1982 
  1983 *** HOL ***
  1984 
  1985 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1986 
  1987 * HOL/inductive package reorganized and improved: now supports mutual
  1988 definitions such as
  1989 
  1990   inductive EVEN ODD
  1991     intrs
  1992       null "0 : EVEN"
  1993       oddI "n : EVEN ==> Suc n : ODD"
  1994       evenI "n : ODD ==> Suc n : EVEN"
  1995 
  1996 new theorem list "elims" contains an elimination rule for each of the
  1997 recursive sets; inductive definitions now handle disjunctive premises
  1998 correctly (also ZF);
  1999 
  2000 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2001 "mutual_induct" no longer exists - the induction rule is always
  2002 contained in "induct";
  2003 
  2004 
  2005 * HOL/datatype package re-implemented and greatly improved: now
  2006 supports mutually recursive datatypes such as
  2007 
  2008   datatype
  2009     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2010             | SUM ('a aexp) ('a aexp)
  2011             | DIFF ('a aexp) ('a aexp)
  2012             | NUM 'a
  2013   and
  2014     'a bexp = LESS ('a aexp) ('a aexp)
  2015             | AND ('a bexp) ('a bexp)
  2016             | OR ('a bexp) ('a bexp)
  2017 
  2018 as well as indirectly recursive datatypes such as
  2019 
  2020   datatype
  2021     ('a, 'b) term = Var 'a
  2022                   | App 'b ((('a, 'b) term) list)
  2023 
  2024 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2025 induction on mutually / indirectly recursive datatypes.
  2026 
  2027 Primrec equations are now stored in theory and can be accessed via
  2028 <function_name>.simps.
  2029 
  2030 INCOMPATIBILITIES:
  2031 
  2032   - Theories using datatypes must now have theory Datatype as an
  2033     ancestor.
  2034   - The specific <typename>.induct_tac no longer exists - use the
  2035     generic induct_tac instead.
  2036   - natE has been renamed to nat.exhaust - use exhaust_tac
  2037     instead of res_inst_tac ... natE. Note that the variable
  2038     names in nat.exhaust differ from the names in natE, this
  2039     may cause some "fragile" proofs to fail.
  2040   - The theorems split_<typename>_case and split_<typename>_case_asm
  2041     have been renamed to <typename>.split and <typename>.split_asm.
  2042   - Since default sorts of type variables are now handled correctly,
  2043     some datatype definitions may have to be annotated with explicit
  2044     sort constraints.
  2045   - Primrec definitions no longer require function name and type
  2046     of recursive argument.
  2047 
  2048 Consider using isatool fixdatatype to adapt your theories and proof
  2049 scripts to the new package (backup your sources first!).
  2050 
  2051 
  2052 * HOL/record package: considerably improved implementation; now
  2053 includes concrete syntax for record types, terms, updates; theorems
  2054 for surjective pairing and splitting !!-bound record variables; proof
  2055 support is as follows:
  2056 
  2057   1) standard conversions (selectors or updates applied to record
  2058 constructor terms) are part of the standard simpset;
  2059 
  2060   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2061 made part of standard simpset and claset via addIffs;
  2062 
  2063   3) a tactic for record field splitting (record_split_tac) is part of
  2064 the standard claset (addSWrapper);
  2065 
  2066 To get a better idea about these rules you may retrieve them via
  2067 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2068 the name of your record type.
  2069 
  2070 The split tactic 3) conceptually simplifies by the following rule:
  2071 
  2072   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2073 
  2074 Thus any record variable that is bound by meta-all will automatically
  2075 blow up into some record constructor term, consequently the
  2076 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2077 solve record problems automatically.
  2078 
  2079 
  2080 * reorganized the main HOL image: HOL/Integ and String loaded by
  2081 default; theory Main includes everything;
  2082 
  2083 * automatic simplification of integer sums and comparisons, using cancellation;
  2084 
  2085 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2086 
  2087 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2088 
  2089 * many new identities for unions, intersections, set difference, etc.;
  2090 
  2091 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2092 called split_if, split_split, split_sum_case and split_nat_case (to go
  2093 with add/delsplits);
  2094 
  2095 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2096 (?x::unit) = (); this is made part of the default simpset, which COULD
  2097 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2098 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2099 unit_abs_eta_conv is added in order to counter the effect of
  2100 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2101 %u.f();
  2102 
  2103 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2104 makes more sense);
  2105 
  2106 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2107   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2108   disjointness reasoning but breaking a few old proofs.
  2109 
  2110 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2111 to 'converse' from 'inverse' (for compatibility with ZF and some
  2112 literature);
  2113 
  2114 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2115 the well-founded relation;
  2116 
  2117 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2118     Compl A.  The "Compl" syntax remains available as input syntax for this
  2119     release ONLY.
  2120 
  2121 * HOL/Update: new theory of function updates:
  2122     f(a:=b) == %x. if x=a then b else f x
  2123 may also be iterated as in f(a:=b,c:=d,...);
  2124 
  2125 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2126 
  2127 * HOL/List:
  2128   - new function list_update written xs[i:=v] that updates the i-th
  2129     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2130   - new function `upt' written [i..j(] which generates the list
  2131     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2132     bound write [i..j], which is a shorthand for [i..j+1(].
  2133   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2134 
  2135 * HOL/Arith:
  2136   - removed 'pred' (predecessor) function;
  2137   - generalized some theorems about n-1;
  2138   - many new laws about "div" and "mod";
  2139   - new laws about greatest common divisors (see theory ex/Primes);
  2140 
  2141 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2142 instead of "inverse";
  2143 
  2144 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2145   of the multiset ordering;
  2146 
  2147 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2148   (not included by default);
  2149 
  2150 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2151 
  2152 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2153   programs, i.e. different program variables may have different types.
  2154 
  2155 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2156   [previously, this check worked only if the rewrite rule was unconditional]
  2157   Now rew can involve either definitions or equalities (either == or =).
  2158 
  2159 
  2160 *** ZF ***
  2161 
  2162 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2163   only the theorems proved on ZF.ML;
  2164 
  2165 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2166   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2167   disjointness reasoning but breaking a few old proofs.
  2168 
  2169 * ZF/Update: new theory of function updates
  2170     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2171   may also be iterated as in f(a:=b,c:=d,...);
  2172 
  2173 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2174 
  2175 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2176   [previously, this check worked only if the rewrite rule was unconditional]
  2177   Now rew can involve either definitions or equalities (either == or =).
  2178 
  2179 * case_tac provided for compatibility with HOL
  2180     (like the old excluded_middle_tac, but with subgoals swapped)
  2181 
  2182 
  2183 *** Internal programming interfaces ***
  2184 
  2185 * Pure: several new basic modules made available for general use, see
  2186 also src/Pure/README;
  2187 
  2188 * improved the theory data mechanism to support encapsulation (data
  2189 kind name replaced by private Object.kind, acting as authorization
  2190 key); new type-safe user interface via functor TheoryDataFun; generic
  2191 print_data function becomes basically useless;
  2192 
  2193 * removed global_names compatibility flag -- all theory declarations
  2194 are qualified by default;
  2195 
  2196 * module Pure/Syntax now offers quote / antiquote translation
  2197 functions (useful for Hoare logic etc. with implicit dependencies);
  2198 see HOL/ex/Antiquote for an example use;
  2199 
  2200 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2201 cterm -> thm;
  2202 
  2203 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2204 subgoal;
  2205 
  2206 * Display.print_goals function moved to Locale.print_goals;
  2207 
  2208 * standard print function for goals supports current_goals_markers
  2209 variable for marking begin of proof, end of proof, start of goal; the
  2210 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2211 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2212 for example;
  2213 
  2214 
  2215 
  2216 New in Isabelle98 (January 1998)
  2217 --------------------------------
  2218 
  2219 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2220 
  2221 * changed lexical syntax of terms / types: dots made part of long
  2222 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2223 
  2224 * simpset (and claset) reference variable replaced by functions
  2225 simpset / simpset_ref;
  2226 
  2227 * no longer supports theory aliases (via merge) and non-trivial
  2228 implicit merge of thms' signatures;
  2229 
  2230 * most internal names of constants changed due to qualified names;
  2231 
  2232 * changed Pure/Sequence interface (see Pure/seq.ML);
  2233 
  2234 
  2235 *** General Changes ***
  2236 
  2237 * hierachically structured name spaces (for consts, types, axms, thms
  2238 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2239 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2240 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2241 long_names for fully qualified output names; NOTE: ML programs
  2242 (special tactics, packages etc.) referring to internal names may have
  2243 to be adapted to cope with fully qualified names; in case of severe
  2244 backward campatibility problems try setting 'global_names' at compile
  2245 time to have enrything declared within a flat name space; one may also
  2246 fine tune name declarations in theories via the 'global' and 'local'
  2247 section;
  2248 
  2249 * reimplemented the implicit simpset and claset using the new anytype
  2250 data filed in signatures; references simpset:simpset ref etc. are
  2251 replaced by functions simpset:unit->simpset and
  2252 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2253 to patch your ML files accordingly;
  2254 
  2255 * HTML output now includes theory graph data for display with Java
  2256 applet or isatool browser; data generated automatically via isatool
  2257 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2258 
  2259 * defs may now be conditional; improved rewrite_goals_tac to handle
  2260 conditional equations;
  2261 
  2262 * defs now admits additional type arguments, using TYPE('a) syntax;
  2263 
  2264 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2265 creates a new theory node; implicit merge of thms' signatures is
  2266 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2267 transfer:theory->thm->thm in (rare) cases;
  2268 
  2269 * improved handling of draft signatures / theories; draft thms (and
  2270 ctyps, cterms) are automatically promoted to real ones;
  2271 
  2272 * slightly changed interfaces for oracles: admit many per theory, named
  2273 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2274 
  2275 * print_goals: optional output of const types (set show_consts and
  2276 show_types);
  2277 
  2278 * improved output of warnings (###) and errors (***);
  2279 
  2280 * subgoal_tac displays a warning if the new subgoal has type variables;
  2281 
  2282 * removed old README and Makefiles;
  2283 
  2284 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2285 
  2286 * removed obsolete init_pps and init_database;
  2287 
  2288 * deleted the obsolete tactical STATE, which was declared by
  2289     fun STATE tacfun st = tacfun st st;
  2290 
  2291 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2292 (which abbreviates $HOME);
  2293 
  2294 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2295 use isatool fixseq to adapt your ML programs (this works for fully
  2296 qualified references to the Sequence structure only!);
  2297 
  2298 * use_thy no longer requires writable current directory; it always
  2299 reloads .ML *and* .thy file, if either one is out of date;
  2300 
  2301 
  2302 *** Classical Reasoner ***
  2303 
  2304 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2305 tactics that use classical reasoning to simplify a subgoal without
  2306 splitting it into several subgoals;
  2307 
  2308 * Safe_tac: like safe_tac but uses the default claset;
  2309 
  2310 
  2311 *** Simplifier ***
  2312 
  2313 * added simplification meta rules:
  2314     (asm_)(full_)simplify: simpset -> thm -> thm;
  2315 
  2316 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2317 logics (again);
  2318 
  2319 * added prems argument to simplification procedures;
  2320 
  2321 * HOL, FOL, ZF: added infix function `addsplits':
  2322   instead of `<simpset> setloop (split_tac <thms>)'
  2323   you can simply write `<simpset> addsplits <thms>'
  2324 
  2325 
  2326 *** Syntax ***
  2327 
  2328 * TYPE('a) syntax for type reflection terms;
  2329 
  2330 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2331 
  2332 * pretty printer: changed order of mixfix annotation preference (again!);
  2333 
  2334 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2335 
  2336 
  2337 *** HOL ***
  2338 
  2339 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2340   with `addloop' of the simplifier to faciliate case splitting in premises.
  2341 
  2342 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2343 
  2344 * HOL/Auth: new protocol proofs including some for the Internet
  2345   protocol TLS;
  2346 
  2347 * HOL/Map: new theory of `maps' a la VDM;
  2348 
  2349 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2350 cancelling out common nat summands from =, <, <= (in)equalities, or
  2351 differences; simplification procedures nat_cancel_factor for
  2352 cancelling common factor from =, <, <= (in)equalities over natural
  2353 sums; nat_cancel contains both kinds of procedures, it is installed by
  2354 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2355 
  2356 * HOL/simplifier: terms of the form
  2357   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2358   are rewritten to
  2359   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2360   and those of the form
  2361   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2362   are rewritten to
  2363   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2364 
  2365 * HOL/datatype
  2366   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2367 
  2368   P(t_case f1 ... fn x) =
  2369      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2370         ...
  2371        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2372      )
  2373 
  2374   and a theorem `split_t_case_asm' of the form
  2375 
  2376   P(t_case f1 ... fn x) =
  2377     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2378         ...
  2379        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2380      )
  2381   which can be added to a simpset via `addsplits'. The existing theorems
  2382   expand_list_case and expand_option_case have been renamed to
  2383   split_list_case and split_option_case.
  2384 
  2385 * HOL/Arithmetic:
  2386   - `pred n' is automatically converted to `n-1'.
  2387     Users are strongly encouraged not to use `pred' any longer,
  2388     because it will disappear altogether at some point.
  2389   - Users are strongly encouraged to write "0 < n" rather than
  2390     "n ~= 0". Theorems and proof tools have been modified towards this
  2391     `standard'.
  2392 
  2393 * HOL/Lists:
  2394   the function "set_of_list" has been renamed "set" (and its theorems too);
  2395   the function "nth" now takes its arguments in the reverse order and
  2396   has acquired the infix notation "!" as in "xs!n".
  2397 
  2398 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2399 
  2400 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2401   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2402 
  2403 * HOL/record: extensible records with schematic structural subtyping
  2404 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2405 still lacks various theorems and concrete record syntax;
  2406 
  2407 
  2408 *** HOLCF ***
  2409 
  2410 * removed "axioms" and "generated by" sections;
  2411 
  2412 * replaced "ops" section by extended "consts" section, which is capable of
  2413   handling the continuous function space "->" directly;
  2414 
  2415 * domain package:
  2416   . proves theorems immediately and stores them in the theory,
  2417   . creates hierachical name space,
  2418   . now uses normal mixfix annotations (instead of cinfix...),
  2419   . minor changes to some names and values (for consistency),
  2420   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2421   . separator between mutual domain defs: changed "," to "and",
  2422   . improved handling of sort constraints;  now they have to
  2423     appear on the left-hand side of the equations only;
  2424 
  2425 * fixed LAM <x,y,zs>.b syntax;
  2426 
  2427 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2428 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2429 
  2430 
  2431 *** FOL and ZF ***
  2432 
  2433 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2434   with `addloop' of the simplifier to faciliate case splitting in premises.
  2435 
  2436 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2437 in HOL, they strip ALL and --> from proved theorems;
  2438 
  2439 
  2440 
  2441 New in Isabelle94-8 (May 1997)
  2442 ------------------------------
  2443 
  2444 *** General Changes ***
  2445 
  2446 * new utilities to build / run / maintain Isabelle etc. (in parts
  2447 still somewhat experimental); old Makefiles etc. still functional;
  2448 
  2449 * new 'Isabelle System Manual';
  2450 
  2451 * INSTALL text, together with ./configure and ./build scripts;
  2452 
  2453 * reimplemented type inference for greater efficiency, better error
  2454 messages and clean internal interface;
  2455 
  2456 * prlim command for dealing with lots of subgoals (an easier way of
  2457 setting goals_limit);
  2458 
  2459 
  2460 *** Syntax ***
  2461 
  2462 * supports alternative (named) syntax tables (parser and pretty
  2463 printer); internal interface is provided by add_modesyntax(_i);
  2464 
  2465 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2466 be used in conjunction with the Isabelle symbol font; uses the
  2467 "symbols" syntax table;
  2468 
  2469 * added token_translation interface (may translate name tokens in
  2470 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2471 the current print_mode); IMPORTANT: user print translation functions
  2472 are responsible for marking newly introduced bounds
  2473 (Syntax.mark_boundT);
  2474 
  2475 * token translations for modes "xterm" and "xterm_color" that display
  2476 names in bold, underline etc. or colors (which requires a color
  2477 version of xterm);
  2478 
  2479 * infixes may now be declared with names independent of their syntax;
  2480 
  2481 * added typed_print_translation (like print_translation, but may
  2482 access type of constant);
  2483 
  2484 
  2485 *** Classical Reasoner ***
  2486 
  2487 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2488 some limitations.  Blast_tac...
  2489   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2490   + ignores elimination rules that don't have the correct format
  2491         (the conclusion MUST be a formula variable)
  2492   + ignores types, which can make HOL proofs fail
  2493   + rules must not require higher-order unification, e.g. apply_type in ZF
  2494     [message "Function Var's argument not a bound variable" relates to this]
  2495   + its proof strategy is more general but can actually be slower
  2496 
  2497 * substitution with equality assumptions no longer permutes other
  2498 assumptions;
  2499 
  2500 * minor changes in semantics of addafter (now called addaltern); renamed
  2501 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2502 (and access functions for it);
  2503 
  2504 * improved combination of classical reasoner and simplifier:
  2505   + functions for handling clasimpsets
  2506   + improvement of addss: now the simplifier is called _after_ the
  2507     safe steps.
  2508   + safe variant of addss called addSss: uses safe simplifications
  2509     _during_ the safe steps. It is more complete as it allows multiple
  2510     instantiations of unknowns (e.g. with slow_tac).
  2511 
  2512 *** Simplifier ***
  2513 
  2514 * added interface for simplification procedures (functions that
  2515 produce *proven* rewrite rules on the fly, depending on current
  2516 redex);
  2517 
  2518 * ordering on terms as parameter (used for ordered rewriting);
  2519 
  2520 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2521 
  2522 * the solver is now split into a safe and an unsafe part.
  2523 This should be invisible for the normal user, except that the
  2524 functions setsolver and addsolver have been renamed to setSolver and
  2525 addSolver; added safe_asm_full_simp_tac;
  2526 
  2527 
  2528 *** HOL ***
  2529 
  2530 * a generic induction tactic `induct_tac' which works for all datatypes and
  2531 also for type `nat';
  2532 
  2533 * a generic case distinction tactic `exhaust_tac' which works for all
  2534 datatypes and also for type `nat';
  2535 
  2536 * each datatype comes with a function `size';
  2537 
  2538 * patterns in case expressions allow tuple patterns as arguments to
  2539 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2540 
  2541 * primrec now also works with type nat;
  2542 
  2543 * recdef: a new declaration form, allows general recursive functions to be
  2544 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2545 
  2546 * the constant for negation has been renamed from "not" to "Not" to
  2547 harmonize with FOL, ZF, LK, etc.;
  2548 
  2549 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2550 infinite lists;
  2551 
  2552 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2553 
  2554 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2555 problems in commutative rings, using axiomatic type classes for + and *;
  2556 
  2557 * more examples in HOL/MiniML and HOL/Auth;
  2558 
  2559 * more default rewrite rules for quantifiers, union/intersection;
  2560 
  2561 * a new constant `arbitrary == @x.False';
  2562 
  2563 * HOLCF/IOA replaces old HOL/IOA;
  2564 
  2565 * HOLCF changes: derived all rules and arities
  2566   + axiomatic type classes instead of classes
  2567   + typedef instead of faking type definitions
  2568   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2569   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2570   + eliminated the types void, one, tr
  2571   + use unit lift and bool lift (with translations) instead of one and tr
  2572   + eliminated blift from Lift3.thy (use Def instead of blift)
  2573   all eliminated rules are derived as theorems --> no visible changes ;
  2574 
  2575 
  2576 *** ZF ***
  2577 
  2578 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2579 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2580 as ZF_cs addSIs [equalityI];
  2581 
  2582 
  2583 
  2584 New in Isabelle94-7 (November 96)
  2585 ---------------------------------
  2586 
  2587 * allowing negative levels (as offsets) in prlev and choplev;
  2588 
  2589 * super-linear speedup for large simplifications;
  2590 
  2591 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2592 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2593 FAIL); can suppress it using the command Delsimps (ex_simps @
  2594 all_simps); De Morgan laws are also now included, by default;
  2595 
  2596 * improved printing of ==>  :  ~:
  2597 
  2598 * new object-logic "Sequents" adds linear logic, while replacing LK
  2599 and Modal (thanks to Sara Kalvala);
  2600 
  2601 * HOL/Auth: correctness proofs for authentication protocols;
  2602 
  2603 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2604 examples on HOL/Auth);
  2605 
  2606 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2607 the rewriter and classical reasoner simultaneously;
  2608 
  2609 * function uresult no longer returns theorems in "standard" format;
  2610 regain previous version by: val uresult = standard o uresult;
  2611 
  2612 
  2613 
  2614 New in Isabelle94-6
  2615 -------------------
  2616 
  2617 * oracles -- these establish an interface between Isabelle and trusted
  2618 external reasoners, which may deliver results as theorems;
  2619 
  2620 * proof objects (in particular record all uses of oracles);
  2621 
  2622 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2623 
  2624 * "constdefs" section in theory files;
  2625 
  2626 * "primrec" section (HOL) no longer requires names;
  2627 
  2628 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2629 
  2630 
  2631 
  2632 New in Isabelle94-5
  2633 -------------------
  2634 
  2635 * reduced space requirements;
  2636 
  2637 * automatic HTML generation from theories;
  2638 
  2639 * theory files no longer require "..." (quotes) around most types;
  2640 
  2641 * new examples, including two proofs of the Church-Rosser theorem;
  2642 
  2643 * non-curried (1994) version of HOL is no longer distributed;
  2644 
  2645 
  2646 
  2647 New in Isabelle94-4
  2648 -------------------
  2649 
  2650 * greatly reduced space requirements;
  2651 
  2652 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2653 
  2654 * searchable theorem database (see the section "Retrieving theorems" on
  2655 page 8 of the Reference Manual);
  2656 
  2657 * new examples, including Grabczewski's monumental case study of the
  2658 Axiom of Choice;
  2659 
  2660 * The previous version of HOL renamed to Old_HOL;
  2661 
  2662 * The new version of HOL (previously called CHOL) uses a curried syntax
  2663 for functions.  Application looks like f a b instead of f(a,b);
  2664 
  2665 * Mutually recursive inductive definitions finally work in HOL;
  2666 
  2667 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2668 translates to the operator "split";
  2669 
  2670 
  2671 
  2672 New in Isabelle94-3
  2673 -------------------
  2674 
  2675 * new infix operator, addss, allowing the classical reasoner to
  2676 perform simplification at each step of its search.  Example:
  2677         fast_tac (cs addss ss)
  2678 
  2679 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2680 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2681 look like (a,b) instead of <a,b>;
  2682 
  2683 * PLEASE NOTE: CHOL will eventually replace HOL!
  2684 
  2685 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2686 It translates to the operator "split".  A new theory of integers is available;
  2687 
  2688 * In ZF, integer numerals now denote two's-complement binary integers.
  2689 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2690 
  2691 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2692 of the Axiom of Choice;
  2693 
  2694 
  2695 
  2696 New in Isabelle94-2
  2697 -------------------
  2698 
  2699 * Significantly faster resolution;
  2700 
  2701 * the different sections in a .thy file can now be mixed and repeated
  2702 freely;
  2703 
  2704 * Database of theorems for FOL, HOL and ZF.  New
  2705 commands including qed, qed_goal and bind_thm store theorems in the database.
  2706 
  2707 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2708 a given theory (thms_of), or find out what theory a theorem was proved in
  2709 (theory_of_thm);
  2710 
  2711 * Bugs fixed in the inductive definition and datatype packages;
  2712 
  2713 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2714 and HOL_dup_cs obsolete;
  2715 
  2716 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2717 have been removed;
  2718 
  2719 * Simpler definition of function space in ZF;
  2720 
  2721 * new results about cardinal and ordinal arithmetic in ZF;
  2722 
  2723 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2724 types;
  2725 
  2726 
  2727 $Id$