NEWS
author paulson
Tue Jun 08 16:40:41 2004 +0200 (2004-06-08)
changeset 14885 0a840138dcd7
parent 14878 b884a7ba7238
child 14897 577f95db94e4
permissions -rw-r--r--
Groups, Rings and supporting lemmas in ZF
     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 * ML: all output via channels of writeln/warning/error etc. is now
    53   passed through Output.output.  This gives interface builders a
    54   chance to adapt text encodings in arbitrary manners (say as XML
    55   entities); see the hook provided by Output.add_mode.  On the other
    56   hand, results of Pretty.string_of/str_of (including string_of_term,
    57   string_of_thm etc.) are still 'raw' (containing funny \<^raw...>
    58   symbols), which requires separate application of Output.output
    59   whenever strings are *not* passed on to writeln/warning/error etc.
    60 
    61 
    62 *** HOL ***
    63 
    64 * HOL/record: reimplementation of records. Improved scalability for
    65   records with many fields, avoiding performance problems for type
    66   inference. Records are no longer composed of nested field types, but
    67   of nested extension types. Therefore the record type only grows
    68   linear in the number of extensions and not in the number of fields.
    69   The top-level (users) view on records is preserved.  Potential
    70   INCOMPATIBILITY only in strange cases, where the theory depends on
    71   the old record representation. The type generated for a record is
    72   called <record_name>_ext_type.
    73 
    74 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
    75 
    76   syntax (epsilon)
    77     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
    78 
    79   The symbol \<some> is displayed as the alternative epsilon of LaTeX
    80   and x-symbol; use option '-m epsilon' to get it actually printed.
    81   Moreover, the mathematically important symbolic identifier
    82   \<epsilon> becomes available as variable, constant etc.
    83 
    84 * Simplifier: "record_upd_simproc" for simplification of multiple
    85   record updates enabled by default.  INCOMPATIBILITY: old proofs
    86   break occasionally, since simplification is more powerful by
    87   default.
    88 
    89 
    90 *** HOLCF ***
    91 
    92 * HOLCF: discontinued special version of 'constdefs' (which used to
    93   support continuous functions) in favor of the general Pure one with
    94   full type-inference.
    95 
    96 
    97 *** ZF ***
    98 
    99 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the First
   100   Isomorphism Theorem (on quotienting by the kernel of a homomorphism).
   101 
   102 
   103 
   104 New in Isabelle2004 (April 2004)
   105 --------------------------------
   106 
   107 *** General ***
   108 
   109 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   110   Replaces linorder.ML.
   111 
   112 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   113   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   114   (\<a>...\<z>), are now considered normal letters, and can therefore
   115   be used anywhere where an ASCII letter (a...zA...Z) has until
   116   now. COMPATIBILITY: This obviously changes the parsing of some
   117   terms, especially where a symbol has been used as a binder, say
   118   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   119   as an identifier.  Fix it by inserting a space around former
   120   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   121   existing theory and ML files.
   122 
   123 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   124 
   125 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   126   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   127   a normal (but invisible) letter. For multiple letter subscripts repeat
   128   \<^isub> like this: x\<^isub>1\<^isub>2.
   129 
   130 * Pure: There are now sub-/superscripts that can span more than one
   131   character. Text between \<^bsub> and \<^esub> is set in subscript in
   132   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   133   superscript. The new control characters are not identifier parts.
   134 
   135 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   136   content of "..." to the latex file instead of \isacntrl... . The "..."
   137   may consist of any printable characters excluding the end bracket >.
   138 
   139 * Pure: Using new Isar command "finalconsts" (or the ML functions
   140   Theory.add_finals or Theory.add_finals_i) it is now possible to
   141   declare constants "final", which prevents their being given a definition
   142   later.  It is useful for constants whose behaviour is fixed axiomatically
   143   rather than definitionally, such as the meta-logic connectives.
   144 
   145 * Pure: 'instance' now handles general arities with general sorts
   146   (i.e. intersections of classes),
   147 
   148 * Presentation: generated HTML now uses a CSS style sheet to make layout
   149   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   150   It can be changed to alter the colors/layout of generated pages.
   151 
   152 
   153 *** Isar ***
   154 
   155 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   156   cut_tac, subgoal_tac and thin_tac:
   157   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   158     locales are no longer forced to write Isar proof scripts.
   159     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   160     emulations.
   161   - INCOMPATIBILITY: names of variables to be instantiated may no
   162     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   163     This is consistent with the instantiation attribute "where".
   164 
   165 * Attributes "where" and "of":
   166   - Now take type variables of instantiated theorem into account when reading
   167     the instantiation string.  This fixes a bug that caused instantiated
   168     theorems to have too special types in some circumstances.
   169   - "where" permits explicit instantiations of type variables.
   170 
   171 * Calculation commands "moreover" and "also" no longer interfere with
   172   current facts ("this"), admitting arbitrary combinations with "then"
   173   and derived forms.
   174 
   175 * Locales:
   176   - Goal statements involving the context element "includes" no longer
   177     generate theorems with internal delta predicates (those ending on
   178     "_axioms") in the premise.
   179     Resolve particular premise with <locale>.intro to obtain old form.
   180   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   181     specification and "includes" elements in goal statement.
   182   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   183     [intro?] and [elim?] (respectively) by default.
   184   - Experimental command for instantiation of locales in proof contexts:
   185         instantiate <label>[<attrs>]: <loc>
   186     Instantiates locale <loc> and adds all its theorems to the current context
   187     taking into account their attributes.  Label and attrs are optional
   188     modifiers, like in theorem declarations.  If present, names of
   189     instantiated theorems are qualified with <label>, and the attributes
   190     <attrs> are applied after any attributes these theorems might have already.
   191       If the locale has assumptions, a chained fact of the form
   192     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   193     are derived.  The command does not support old-style locales declared
   194     with "locale (open)".
   195       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   196 
   197 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   198   (Isar) contexts.
   199 
   200 
   201 *** HOL ***
   202 
   203 * Proof import: new image HOL4 contains the imported library from
   204   the HOL4 system with about 2500 theorems. It is imported by
   205   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   206   can be used like any other Isabelle image.  See
   207   HOL/Import/HOL/README for more information.
   208 
   209 * Simplifier:
   210   - Much improved handling of linear and partial orders.
   211     Reasoners for linear and partial orders are set up for type classes
   212     "linorder" and "order" respectively, and are added to the default simpset
   213     as solvers.  This means that the simplifier can build transitivity chains
   214     to solve goals from the assumptions.
   215   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   216     of blast or auto after simplification become unnecessary because the goal
   217     is solved by simplification already.
   218 
   219 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   220     all proved in axiomatic type classes for semirings, rings and fields.
   221 
   222 * Numerics:
   223   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   224     now formalized using the Ring_and_Field theory mentioned above.
   225   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   226     than before, because now they are set up once in a generic manner.
   227   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   228     Look for the general versions in Ring_and_Field (and Power if they concern
   229     exponentiation).
   230 
   231 * Type "rat" of the rational numbers is now available in HOL-Complex.
   232 
   233 * Records:
   234   - Record types are now by default printed with their type abbreviation
   235     instead of the list of all field types. This can be configured via
   236     the reference "print_record_type_abbr".
   237   - Simproc "record_upd_simproc" for simplification of multiple updates added
   238     (not enabled by default).
   239   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   240     EX x. x = sel r to True (not enabled by default).
   241   - Tactic "record_split_simp_tac" to split and simplify records added.
   242 
   243 * 'specification' command added, allowing for definition by
   244   specification.  There is also an 'ax_specification' command that
   245   introduces the new constants axiomatically.
   246 
   247 * arith(_tac) is now able to generate counterexamples for reals as well.
   248 
   249 * HOL-Algebra: new locale "ring" for non-commutative rings.
   250 
   251 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   252   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   253 
   254 * HOL-Matrix: a first theory for matrices in HOL with an application of
   255   matrix theory to linear programming.
   256 
   257 * Unions and Intersections:
   258   The x-symbol output syntax of UN and INT has been changed
   259   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   260   i.e. the index formulae has become a subscript, like in normal math.
   261   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   262   The subscript version is also accepted as input syntax.
   263 
   264 * Unions and Intersections over Intervals:
   265   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   266   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   267   like in normal math, and corresponding versions for < and for intersection.
   268 
   269 * ML: the legacy theory structures Int and List have been removed. They had
   270   conflicted with ML Basis Library structures having the same names.
   271 
   272 * 'refute' command added to search for (finite) countermodels.  Only works
   273   for a fragment of HOL.  The installation of an external SAT solver is
   274   highly recommended.  See "HOL/Refute.thy" for details.
   275 
   276 * 'quickcheck' command: Allows to find counterexamples by evaluating
   277   formulae under an assignment of free variables to random values.
   278   In contrast to 'refute', it can deal with inductive datatypes,
   279   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   280   for examples.
   281 
   282 
   283 *** HOLCF ***
   284 
   285 * Streams now come with concatenation and are part of the HOLCF image
   286 
   287 
   288 
   289 New in Isabelle2003 (May 2003)
   290 ------------------------------
   291 
   292 *** General ***
   293 
   294 * Provers/simplifier:
   295 
   296   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   297     Assumptions are now subject to complete mutual simplification,
   298     not just from left to right. The simplifier now preserves
   299     the order of assumptions.
   300 
   301     Potential INCOMPATIBILITY:
   302 
   303     -- simp sometimes diverges where the old version did
   304        not, e.g. invoking simp on the goal
   305 
   306         [| P (f x); y = x; f x = f y |] ==> Q
   307 
   308        now gives rise to the infinite reduction sequence
   309 
   310         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   311 
   312        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   313        kind of problem.
   314 
   315     -- Tactics combining classical reasoner and simplification (such as auto)
   316        are also affected by this change, because many of them rely on
   317        simp. They may sometimes diverge as well or yield a different numbers
   318        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   319        in case of problems. Sometimes subsequent calls to the classical
   320        reasoner will fail because a preceeding call to the simplifier too
   321        eagerly simplified the goal, e.g. deleted redundant premises.
   322 
   323   - The simplifier trace now shows the names of the applied rewrite rules
   324 
   325   - You can limit the number of recursive invocations of the simplifier
   326     during conditional rewriting (where the simplifie tries to solve the
   327     conditions before applying the rewrite rule):
   328     ML "simp_depth_limit := n"
   329     where n is an integer. Thus you can force termination where previously
   330     the simplifier would diverge.
   331 
   332   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   333 
   334   - No longer aborts on failed congruence proof.  Instead, the
   335     congruence is ignored.
   336 
   337 * Pure: New generic framework for extracting programs from constructive
   338   proofs. See HOL/Extraction.thy for an example instantiation, as well
   339   as HOL/Extraction for some case studies.
   340 
   341 * Pure: The main goal of the proof state is no longer shown by default, only
   342 the subgoals. This behaviour is controlled by a new flag.
   343    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   344 (ML: Proof.show_main_goal).
   345 
   346 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   347 rules whose conclusion matches subgoal 1:
   348       PG menu: Isabelle/Isar -> Show me -> matching rules
   349 The rules are ordered by how closely they match the subgoal.
   350 In particular, rules that solve a subgoal outright are displayed first
   351 (or rather last, the way they are printed).
   352 (ML: ProofGeneral.print_intros())
   353 
   354 * Pure: New flag trace_unify_fail causes unification to print
   355 diagnostic information (PG: in trace buffer) when it fails. This is
   356 useful for figuring out why single step proofs like rule, erule or
   357 assumption failed.
   358 
   359 * Pure: Locale specifications now produce predicate definitions
   360 according to the body of text (covering assumptions modulo local
   361 definitions); predicate "loc_axioms" covers newly introduced text,
   362 while "loc" is cumulative wrt. all included locale expressions; the
   363 latter view is presented only on export into the global theory
   364 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   365 on the old view without predicates;
   366 
   367 * Pure: predefined locales "var" and "struct" are useful for sharing
   368 parameters (as in CASL, for example); just specify something like
   369 ``var x + var y + struct M'' as import;
   370 
   371 * Pure: improved thms_containing: proper indexing of facts instead of
   372 raw theorems; check validity of results wrt. current name space;
   373 include local facts of proof configuration (also covers active
   374 locales), cover fixed variables in index; may use "_" in term
   375 specification; an optional limit for the number of printed facts may
   376 be given (the default is 40);
   377 
   378 * Pure: disallow duplicate fact bindings within new-style theory files
   379 (batch-mode only);
   380 
   381 * Provers: improved induct method: assumptions introduced by case
   382 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   383 the goal statement); "foo" still refers to all facts collectively;
   384 
   385 * Provers: the function blast.overloaded has been removed: all constants
   386 are regarded as potentially overloaded, which improves robustness in exchange
   387 for slight decrease in efficiency;
   388 
   389 * Provers/linorder: New generic prover for transitivity reasoning over
   390 linear orders.  Note: this prover is not efficient!
   391 
   392 * Isar: preview of problems to finish 'show' now produce an error
   393 rather than just a warning (in interactive mode);
   394 
   395 
   396 *** HOL ***
   397 
   398 * arith(_tac)
   399 
   400  - Produces a counter example if it cannot prove a goal.
   401    Note that the counter example may be spurious if the goal is not a formula
   402    of quantifier-free linear arithmetic.
   403    In ProofGeneral the counter example appears in the trace buffer.
   404 
   405  - Knows about div k and mod k where k is a numeral of type nat or int.
   406 
   407  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   408    linear arithmetic fails. This takes account of quantifiers and divisibility.
   409    Presburger arithmetic can also be called explicitly via presburger(_tac).
   410 
   411 * simp's arithmetic capabilities have been enhanced a bit: it now
   412 takes ~= in premises into account (by performing a case split);
   413 
   414 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   415 are distributed over a sum of terms;
   416 
   417 * New tactic "trans_tac" and method "trans" instantiate
   418 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   419 "<=", "<" and "=").
   420 
   421 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   422 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   423 
   424 * 'typedef' command has new option "open" to suppress the set
   425 definition;
   426 
   427 * functions Min and Max on finite sets have been introduced (theory
   428 Finite_Set);
   429 
   430 * attribute [symmetric] now works for relations as well; it turns
   431 (x,y) : R^-1 into (y,x) : R, and vice versa;
   432 
   433 * induct over a !!-quantified statement (say !!x1..xn):
   434   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   435 
   436 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   437 %x. None. Warning: empty_def now refers to the previously hidden definition
   438 of the empty set.
   439 
   440 * Algebra: formalization of classical algebra.  Intended as base for
   441 any algebraic development in Isabelle.  Currently covers group theory
   442 (up to Sylow's theorem) and ring theory (Universal Property of
   443 Univariate Polynomials).  Contributions welcome;
   444 
   445 * GroupTheory: deleted, since its material has been moved to Algebra;
   446 
   447 * Complex: new directory of the complex numbers with numeric constants,
   448 nonstandard complex numbers, and some complex analysis, standard and
   449 nonstandard (Jacques Fleuriot);
   450 
   451 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   452 
   453 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   454 Fleuriot);
   455 
   456 * Real/HahnBanach: updated and adapted to locales;
   457 
   458 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   459 Gray and Kramer);
   460 
   461 * UNITY: added the Meier-Sanders theory of progress sets;
   462 
   463 * MicroJava: bytecode verifier and lightweight bytecode verifier
   464 as abstract algorithms, instantiated to the JVM;
   465 
   466 * Bali: Java source language formalization. Type system, operational
   467 semantics, axiomatic semantics. Supported language features:
   468 classes, interfaces, objects,virtual methods, static methods,
   469 static/instance fields, arrays, access modifiers, definite
   470 assignment, exceptions.
   471 
   472 
   473 *** ZF ***
   474 
   475 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   476 universe, etc.);
   477 
   478 * Main ZF: virtually all theories converted to new-style format;
   479 
   480 
   481 *** ML ***
   482 
   483 * Pure: Tactic.prove provides sane interface for internal proofs;
   484 omits the infamous "standard" operation, so this is more appropriate
   485 than prove_goalw_cterm in many situations (e.g. in simprocs);
   486 
   487 * Pure: improved error reporting of simprocs;
   488 
   489 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   490 up simprocs;
   491 
   492 
   493 *** Document preparation ***
   494 
   495 * uses \par instead of \\ for line breaks in theory text. This may
   496 shift some page breaks in large documents. To get the old behaviour
   497 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   498 
   499 * minimized dependencies of isabelle.sty and isabellesym.sty on
   500 other packages
   501 
   502 * \<euro> now needs package babel/greek instead of marvosym (which
   503 broke \Rightarrow)
   504 
   505 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   506 textcomp package)
   507 
   508 
   509 
   510 New in Isabelle2002 (March 2002)
   511 --------------------------------
   512 
   513 *** Document preparation ***
   514 
   515 * greatly simplified document preparation setup, including more
   516 graceful interpretation of isatool usedir -i/-d/-D options, and more
   517 instructive isatool mkdir; users should basically be able to get
   518 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   519 users may run a separate document processing stage manually like this:
   520 "isatool usedir -D output HOL Test && isatool document Test/output";
   521 
   522 * theory dependency graph may now be incorporated into documents;
   523 isatool usedir -g true will produce session_graph.eps/.pdf for use
   524 with \includegraphics of LaTeX;
   525 
   526 * proper spacing of consecutive markup elements, especially text
   527 blocks after section headings;
   528 
   529 * support bold style (for single symbols only), input syntax is like
   530 this: "\<^bold>\<alpha>" or "\<^bold>A";
   531 
   532 * \<bullet> is now output as bold \cdot by default, which looks much
   533 better in printed text;
   534 
   535 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   536 note that these symbols are currently unavailable in Proof General /
   537 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   538 
   539 * isatool latex no longer depends on changed TEXINPUTS, instead
   540 isatool document copies the Isabelle style files to the target
   541 location;
   542 
   543 
   544 *** Isar ***
   545 
   546 * Pure/Provers: improved proof by cases and induction;
   547   - 'case' command admits impromptu naming of parameters (such as
   548     "case (Suc n)");
   549   - 'induct' method divinates rule instantiation from the inductive
   550     claim; no longer requires excessive ?P bindings for proper
   551     instantiation of cases;
   552   - 'induct' method properly enumerates all possibilities of set/type
   553     rules; as a consequence facts may be also passed through *type*
   554     rules without further ado;
   555   - 'induct' method now derives symbolic cases from the *rulified*
   556     rule (before it used to rulify cases stemming from the internal
   557     atomized version); this means that the context of a non-atomic
   558     statement becomes is included in the hypothesis, avoiding the
   559     slightly cumbersome show "PROP ?case" form;
   560   - 'induct' may now use elim-style induction rules without chaining
   561     facts, using ``missing'' premises from the goal state; this allows
   562     rules stemming from inductive sets to be applied in unstructured
   563     scripts, while still benefitting from proper handling of non-atomic
   564     statements; NB: major inductive premises need to be put first, all
   565     the rest of the goal is passed through the induction;
   566   - 'induct' proper support for mutual induction involving non-atomic
   567     rule statements (uses the new concept of simultaneous goals, see
   568     below);
   569   - append all possible rule selections, but only use the first
   570     success (no backtracking);
   571   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   572   - undeclared rule case names default to numbers 1, 2, 3, ...;
   573   - added 'print_induct_rules' (covered by help item in recent Proof
   574     General versions);
   575   - moved induct/cases attributes to Pure, methods to Provers;
   576   - generic method setup instantiated for FOL and HOL;
   577 
   578 * Pure: support multiple simultaneous goal statements, for example
   579 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   580 meta-level mechanism, this acts as if several individual goals had
   581 been stated separately; in particular common proof methods need to be
   582 repeated in order to cover all claims; note that a single elimination
   583 step is *not* sufficient to establish the two conjunctions, so this
   584 fails:
   585 
   586   assume "A & B" then have A and B ..   (*".." fails*)
   587 
   588 better use "obtain" in situations as above; alternative refer to
   589 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   590 
   591 * Pure: proper integration with ``locales''; unlike the original
   592 version by Florian Kammüller, Isar locales package high-level proof
   593 contexts rather than raw logical ones (e.g. we admit to include
   594 attributes everywhere); operations on locales include merge and
   595 rename; support for implicit arguments (``structures''); simultaneous
   596 type-inference over imports and text; see also HOL/ex/Locales.thy for
   597 some examples;
   598 
   599 * Pure: the following commands have been ``localized'', supporting a
   600 target locale specification "(in name)": 'lemma', 'theorem',
   601 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   602 stored both within the locale and at the theory level (exported and
   603 qualified by the locale name);
   604 
   605 * Pure: theory goals may now be specified in ``long'' form, with
   606 ad-hoc contexts consisting of arbitrary locale elements. for example
   607 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   608 definitions may be given, too); the result is a meta-level rule with
   609 the context elements being discharged in the obvious way;
   610 
   611 * Pure: new proof command 'using' allows to augment currently used
   612 facts after a goal statement ('using' is syntactically analogous to
   613 'apply', but acts on the goal's facts only); this allows chained facts
   614 to be separated into parts given before and after a claim, as in
   615 ``from a and b have C using d and e <proof>'';
   616 
   617 * Pure: renamed "antecedent" case to "rule_context";
   618 
   619 * Pure: new 'judgment' command records explicit information about the
   620 object-logic embedding (used by several tools internally); no longer
   621 use hard-wired "Trueprop";
   622 
   623 * Pure: added 'corollary' command;
   624 
   625 * Pure: fixed 'token_translation' command;
   626 
   627 * Pure: removed obsolete 'exported' attribute;
   628 
   629 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   630 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   631 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   632 
   633 * Pure: method 'atomize' presents local goal premises as object-level
   634 statements (atomic meta-level propositions); setup controlled via
   635 rewrite rules declarations of 'atomize' attribute; example
   636 application: 'induct' method with proper rule statements in improper
   637 proof *scripts*;
   638 
   639 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   640 now consider the syntactic context of assumptions, giving a better
   641 chance to get type-inference of the arguments right (this is
   642 especially important for locales);
   643 
   644 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   645 mode;
   646 
   647 * Pure/obtain: the formal conclusion "thesis", being marked as
   648 ``internal'', may no longer be reference directly in the text;
   649 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   650 situations;
   651 
   652 * Pure: generic 'sym' attribute which declares a rule both as pure
   653 'elim?' and for the 'symmetric' operation;
   654 
   655 * Pure: marginal comments ``--'' may now occur just anywhere in the
   656 text; the fixed correlation with particular command syntax has been
   657 discontinued;
   658 
   659 * Pure: new method 'rules' is particularly well-suited for proof
   660 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   661 but often produces more compact proof terms with less detours;
   662 
   663 * Pure/Provers/classical: simplified integration with pure rule
   664 attributes and methods; the classical "intro?/elim?/dest?"
   665 declarations coincide with the pure ones; the "rule" method no longer
   666 includes classically swapped intros; "intro" and "elim" methods no
   667 longer pick rules from the context; also got rid of ML declarations
   668 AddXIs/AddXEs/AddXDs; all of this has some potential for
   669 INCOMPATIBILITY;
   670 
   671 * Provers/classical: attribute 'swapped' produces classical inversions
   672 of introduction rules;
   673 
   674 * Provers/simplifier: 'simplified' attribute may refer to explicit
   675 rules instead of full simplifier context; 'iff' attribute handles
   676 conditional rules;
   677 
   678 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   679 
   680 * HOL: 'recdef' now fails on unfinished automated proofs, use
   681 "(permissive)" option to recover old behavior;
   682 
   683 * HOL: 'inductive' no longer features separate (collective) attributes
   684 for 'intros' (was found too confusing);
   685 
   686 * HOL: properly declared induction rules less_induct and
   687 wf_induct_rule;
   688 
   689 
   690 *** HOL ***
   691 
   692 * HOL: moved over to sane numeral syntax; the new policy is as
   693 follows:
   694 
   695   - 0 and 1 are polymorphic constants, which are defined on any
   696   numeric type (nat, int, real etc.);
   697 
   698   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   699   binary representation internally;
   700 
   701   - type nat has special constructor Suc, and generally prefers Suc 0
   702   over 1::nat and Suc (Suc 0) over 2::nat;
   703 
   704 This change may cause significant problems of INCOMPATIBILITY; here
   705 are some hints on converting existing sources:
   706 
   707   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   708   entities, so expressions involving "-" (unary or binary minus) need
   709   to be spaced properly;
   710 
   711   - existing occurrences of "1" may need to be constraint "1::nat" or
   712   even replaced by Suc 0; similar for old "2";
   713 
   714   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   715 
   716   - remove all special provisions on numerals in proofs;
   717 
   718 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   719 representation (depends on bin_arith_simps in the default context);
   720 
   721 * HOL: symbolic syntax for x^2 (numeral 2);
   722 
   723 * HOL: the class of all HOL types is now called "type" rather than
   724 "term"; INCOMPATIBILITY, need to adapt references to this type class
   725 in axclass/classes, instance/arities, and (usually rare) occurrences
   726 in typings (of consts etc.); internally the class is called
   727 "HOL.type", ML programs should refer to HOLogic.typeS;
   728 
   729 * HOL/record package improvements:
   730   - new derived operations "fields" to build a partial record section,
   731     "extend" to promote a fixed record to a record scheme, and
   732     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   733     declared as simp by default;
   734   - shared operations ("more", "fields", etc.) now need to be always
   735     qualified) --- potential INCOMPATIBILITY;
   736   - removed "make_scheme" operations (use "make" with "extend") --
   737     INCOMPATIBILITY;
   738   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   739   - provides cases/induct rules for use with corresponding Isar
   740     methods (for concrete records, record schemes, concrete more
   741     parts, and schematic more parts -- in that order);
   742   - internal definitions directly based on a light-weight abstract
   743     theory of product types over typedef rather than datatype;
   744 
   745 * HOL: generic code generator for generating executable ML code from
   746 specifications; specific support for HOL constructs such as inductive
   747 datatypes and sets, as well as recursive functions; can be invoked
   748 via 'generate_code' theory section;
   749 
   750 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   751 
   752 * HOL: consolidated and renamed several theories.  In particular:
   753         Ord.thy has been absorbed into HOL.thy
   754         String.thy has been absorbed into List.thy
   755 
   756 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   757 (beware of argument permutation!);
   758 
   759 * HOL: linorder_less_split superseded by linorder_cases;
   760 
   761 * HOL/List: "nodups" renamed to "distinct";
   762 
   763 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   764 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   765   - Ex_def has changed, now need to use some_eq_ex
   766 
   767 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   768 in this (rare) case use:
   769 
   770   delSWrapper "split_all_tac"
   771   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   772 
   773 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   774 MAY FAIL;
   775 
   776 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   777 Isabelle's type classes, ^ on functions and relations has too general
   778 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   779 necessary to attach explicit type constraints;
   780 
   781 * HOL/Relation: the prefix name of the infix "O" has been changed from
   782 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   783 renamed accordingly (eg "compI" -> "rel_compI").
   784 
   785 * HOL: syntax translations now work properly with numerals and records
   786 expressions;
   787 
   788 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   789 of "lam" -- INCOMPATIBILITY;
   790 
   791 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   792 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   793 renamed "Product_Type.unit";
   794 
   795 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   796 
   797 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   798 the "cases" method);
   799 
   800 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   801 Florian Kammüller);
   802 
   803 * HOL/IMP: updated and converted to new-style theory format; several
   804 parts turned into readable document, with proper Isar proof texts and
   805 some explanations (by Gerwin Klein);
   806 
   807 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   808 
   809 * HOL-Hyperreal is now a logic image;
   810 
   811 
   812 *** HOLCF ***
   813 
   814 * Isar: consts/constdefs supports mixfix syntax for continuous
   815 operations;
   816 
   817 * Isar: domain package adapted to new-style theory format, e.g. see
   818 HOLCF/ex/Dnat.thy;
   819 
   820 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   821 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   822 lift.induct_tac, always use UU instead of Undef;
   823 
   824 * HOLCF/IMP: updated and converted to new-style theory;
   825 
   826 
   827 *** ZF ***
   828 
   829 * Isar: proper integration of logic-specific tools and packages,
   830 including theory commands '(co)inductive', '(co)datatype',
   831 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   832 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   833 
   834 * theory Main no longer includes AC; for the Axiom of Choice, base
   835 your theory on Main_ZFC;
   836 
   837 * the integer library now covers quotients and remainders, with many
   838 laws relating division to addition, multiplication, etc.;
   839 
   840 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   841 typeless version of the formalism;
   842 
   843 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   844 format;
   845 
   846 * ZF/Induct: new directory for examples of inductive definitions,
   847 including theory Multiset for multiset orderings; converted to
   848 new-style theory format;
   849 
   850 * ZF: many new theorems about lists, ordinals, etc.;
   851 
   852 
   853 *** General ***
   854 
   855 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   856 variable proof controls level of detail: 0 = no proofs (only oracle
   857 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   858 also ref manual for further ML interfaces;
   859 
   860 * Pure/axclass: removed obsolete ML interface
   861 goal_subclass/goal_arity;
   862 
   863 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   864 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   865 separate tokens, so expressions involving minus need to be spaced
   866 properly;
   867 
   868 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   869 rather than "infixl" or "infixr";
   870 
   871 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   872 sort constraint specifications in type inference; e.g. "x::_::foo"
   873 ensures that the type of "x" is of sort "foo" (but not necessarily a
   874 type variable);
   875 
   876 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   877 control output of nested => (types); the default behavior is
   878 "type_brackets";
   879 
   880 * Pure/syntax: builtin parse translation for "_constify" turns valued
   881 tokens into AST constants;
   882 
   883 * Pure/syntax: prefer later declarations of translations and print
   884 translation functions; potential INCOMPATIBILITY: need to reverse
   885 multiple declarations for same syntax element constant;
   886 
   887 * Pure/show_hyps reset by default (in accordance to existing Isar
   888 practice);
   889 
   890 * Provers/classical: renamed addaltern to addafter, addSaltern to
   891 addSafter;
   892 
   893 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   894 as well;
   895 
   896 * system: tested support for MacOS X; should be able to get Isabelle +
   897 Proof General to work in a plain Terminal after installing Poly/ML
   898 (e.g. from the Isabelle distribution area) and GNU bash alone
   899 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   900 support requires further installations, e.g. from
   901 http://fink.sourceforge.net/);
   902 
   903 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   904 
   905 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   906 of 40 MB), cf. ML_OPTIONS;
   907 
   908 * system: Proof General keywords specification is now part of the
   909 Isabelle distribution (see etc/isar-keywords.el);
   910 
   911 * system: support for persistent Proof General sessions (refrain from
   912 outdating all loaded theories on startup); user may create writable
   913 logic images like this: ``isabelle -q HOL Test'';
   914 
   915 * system: smart selection of Isabelle process versus Isabelle
   916 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   917 run both "isabelle" and "Isabelle" even if file names are badly
   918 damaged (executable inspects the case of the first letter of its own
   919 name); added separate "isabelle-process" and "isabelle-interface";
   920 
   921 * system: refrain from any attempt at filtering input streams; no
   922 longer support ``8bit'' encoding of old isabelle font, instead proper
   923 iso-latin characters may now be used; the related isatools
   924 "symbolinput" and "nonascii" have disappeared as well;
   925 
   926 * system: removed old "xterm" interface (the print modes "xterm" and
   927 "xterm_color" are still available for direct use in a suitable
   928 terminal);
   929 
   930 
   931 
   932 New in Isabelle99-2 (February 2001)
   933 -----------------------------------
   934 
   935 *** Overview of INCOMPATIBILITIES ***
   936 
   937 * HOL: please note that theories in the Library and elsewhere often use the
   938 new-style (Isar) format; to refer to their theorems in an ML script you must
   939 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   940 
   941 * HOL: inductive package no longer splits induction rule aggressively,
   942 but only as far as specified by the introductions given; the old
   943 format may be recovered via ML function complete_split_rule or attribute
   944 'split_rule (complete)';
   945 
   946 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   947 gfp_Tarski to gfp_unfold;
   948 
   949 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   950 
   951 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   952 relation); infix "^^" has been renamed "``"; infix "``" has been
   953 renamed "`"; "univalent" has been renamed "single_valued";
   954 
   955 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   956 operation;
   957 
   958 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   959 
   960 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   961 
   962 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   963 consequence, it is no longer monotonic wrt. the local goal context
   964 (which is now passed through the inductive cases);
   965 
   966 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   967 \<gg> to \<ggreater>;
   968 
   969 
   970 *** Document preparation ***
   971 
   972 * \isabellestyle{NAME} selects version of Isabelle output (currently
   973 available: are "it" for near math-mode best-style output, "sl" for
   974 slanted text style, and "tt" for plain type-writer; if no
   975 \isabellestyle command is given, output is according to slanted
   976 type-writer);
   977 
   978 * support sub/super scripts (for single symbols only), input syntax is
   979 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   980 
   981 * some more standard symbols; see Appendix A of the system manual for
   982 the complete list of symbols defined in isabellesym.sty;
   983 
   984 * improved isabelle style files; more abstract symbol implementation
   985 (should now use \isamath{...} and \isatext{...} in custom symbol
   986 definitions);
   987 
   988 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   989 state; Note that presentation of goal states does not conform to
   990 actual human-readable proof documents.  Please do not include goal
   991 states into document output unless you really know what you are doing!
   992 
   993 * proper indentation of antiquoted output with proportional LaTeX
   994 fonts;
   995 
   996 * no_document ML operator temporarily disables LaTeX document
   997 generation;
   998 
   999 * isatool unsymbolize tunes sources for plain ASCII communication;
  1000 
  1001 
  1002 *** Isar ***
  1003 
  1004 * Pure: Isar now suffers initial goal statements to contain unbound
  1005 schematic variables (this does not conform to actual readable proof
  1006 documents, due to unpredictable outcome and non-compositional proof
  1007 checking); users who know what they are doing may use schematic goals
  1008 for Prolog-style synthesis of proven results;
  1009 
  1010 * Pure: assumption method (an implicit finishing) now handles actual
  1011 rules as well;
  1012 
  1013 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1014 initial goal, declare "that" only as Pure intro (only for single
  1015 steps); the "that" rule assumption may now be involved in implicit
  1016 finishing, thus ".." becomes a feasible for trivial obtains;
  1017 
  1018 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1019 instance proofs may be performed by "..";
  1020 
  1021 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1022 statements as well;
  1023 
  1024 * Pure: more robust selection of calculational rules;
  1025 
  1026 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1027 rule (as well as the assumption rule);
  1028 
  1029 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1030 lemmas, using the graph browser tool;
  1031 
  1032 * Pure: predict failure of "show" in interactive mode;
  1033 
  1034 * Pure: 'thms_containing' now takes actual terms as arguments;
  1035 
  1036 * HOL: improved method 'induct' --- now handles non-atomic goals
  1037 (potential INCOMPATIBILITY); tuned error handling;
  1038 
  1039 * HOL: cases and induct rules now provide explicit hints about the
  1040 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1041 any remaining facts are inserted into the goal verbatim;
  1042 
  1043 * HOL: local contexts (aka cases) may now contain term bindings as
  1044 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1045 the result to be shown in each case;
  1046 
  1047 * HOL: added 'recdef_tc' command;
  1048 
  1049 * isatool convert assists in eliminating legacy ML scripts;
  1050 
  1051 
  1052 *** HOL ***
  1053 
  1054 * HOL/Library: a collection of generic theories to be used together
  1055 with main HOL; the theory loader path already includes this directory
  1056 by default; the following existing theories have been moved here:
  1057 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1058 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1059 
  1060 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1061 modelling and verification task performed in Isabelle/HOL +
  1062 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1063 
  1064 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1065 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1066 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1067 'domain', this makes the theory consistent with mathematical
  1068 literature;
  1069 
  1070 * HOL basics: added overloaded operations "inverse" and "divide"
  1071 (infix "/"), syntax for generic "abs" operation, generic summation
  1072 operator \<Sum>;
  1073 
  1074 * HOL/typedef: simplified package, provide more useful rules (see also
  1075 HOL/subset.thy);
  1076 
  1077 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1078 now expressed as a proper nested rule (old-style tactic scripts may
  1079 require atomize_strip_tac to cope with non-atomic premises);
  1080 
  1081 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1082 to "split_conv" (old name still available for compatibility);
  1083 
  1084 * HOL: improved concrete syntax for strings (e.g. allows translation
  1085 rules with string literals);
  1086 
  1087 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1088  and Fleuriot's mechanization of analysis, including the transcendental
  1089  functions for the reals;
  1090 
  1091 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1092 
  1093 
  1094 *** CTT ***
  1095 
  1096 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1097 "lam" is displayed as TWO lambda-symbols
  1098 
  1099 * CTT: theory Main now available, containing everything (that is, Bool
  1100 and Arith);
  1101 
  1102 
  1103 *** General ***
  1104 
  1105 * Pure: the Simplifier has been implemented properly as a derived rule
  1106 outside of the actual kernel (at last!); the overall performance
  1107 penalty in practical applications is about 50%, while reliability of
  1108 the Isabelle inference kernel has been greatly improved;
  1109 
  1110 * print modes "brackets" and "no_brackets" control output of nested =>
  1111 (types) and ==> (props); the default behaviour is "brackets";
  1112 
  1113 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1114 as assumptions as well;
  1115 
  1116 * system: support Poly/ML 4.0;
  1117 
  1118 * system: isatool install handles KDE version 1 or 2;
  1119 
  1120 
  1121 
  1122 New in Isabelle99-1 (October 2000)
  1123 ----------------------------------
  1124 
  1125 *** Overview of INCOMPATIBILITIES ***
  1126 
  1127 * HOL: simplification of natural numbers is much changed; to partly
  1128 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1129 issue the following ML commands:
  1130 
  1131   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1132   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1133 
  1134 * HOL: simplification no longer dives into case-expressions; this is
  1135 controlled by "t.weak_case_cong" for each datatype t;
  1136 
  1137 * HOL: nat_less_induct renamed to less_induct;
  1138 
  1139 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1140 fixsome to patch .thy and .ML sources automatically;
  1141 
  1142   select_equality  -> some_equality
  1143   select_eq_Ex     -> some_eq_ex
  1144   selectI2EX       -> someI2_ex
  1145   selectI2         -> someI2
  1146   selectI          -> someI
  1147   select1_equality -> some1_equality
  1148   Eps_sym_eq       -> some_sym_eq_trivial
  1149   Eps_eq           -> some_eq_trivial
  1150 
  1151 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1152 
  1153 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1154 instead);
  1155 
  1156 * HOL: the recursion equations generated by 'recdef' are now called
  1157 f.simps instead of f.rules;
  1158 
  1159 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1160 
  1161 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1162 sometimes be needed;
  1163 
  1164 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1165 
  1166 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1167 
  1168 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1169 product is now "<*>" instead of "Times"; the lexicographic product is
  1170 now "<*lex*>" instead of "**";
  1171 
  1172 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1173 of main HOL, but was unused); better use HOL's datatype package;
  1174 
  1175 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1176 the old syntax may be recovered as follows:
  1177 
  1178   syntax (symbols)
  1179     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1180       (infixl "\\<oplus>" 100)
  1181 
  1182 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1183 
  1184 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1185 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1186 internally;
  1187 
  1188 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1189 changed from A/r to A//r;
  1190 
  1191 * ZF: new treatment of arithmetic (nat & int) may break some old
  1192 proofs;
  1193 
  1194 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1195 rulify -> rule_format, elimify -> elim_format, ...);
  1196 
  1197 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1198 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1199 should have to change intro!! to intro? only); replaced "delrule" by
  1200 "rule del";
  1201 
  1202 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1203 
  1204 * Provers: strengthened force_tac by using new first_best_tac;
  1205 
  1206 * LaTeX document preparation: several changes of isabelle.sty (see
  1207 lib/texinputs);
  1208 
  1209 
  1210 *** Document preparation ***
  1211 
  1212 * formal comments (text blocks etc.) in new-style theories may now
  1213 contain antiquotations of thm/prop/term/typ/text to be presented
  1214 according to latex print mode; concrete syntax is like this:
  1215 @{term[show_types] "f(x) = a + x"};
  1216 
  1217 * isatool mkdir provides easy setup of Isabelle session directories,
  1218 including proper document sources;
  1219 
  1220 * generated LaTeX sources are now deleted after successful run
  1221 (isatool document -c); may retain a copy somewhere else via -D option
  1222 of isatool usedir;
  1223 
  1224 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1225 style files, achieving self-contained LaTeX sources and simplifying
  1226 LaTeX debugging;
  1227 
  1228 * old-style theories now produce (crude) LaTeX output as well;
  1229 
  1230 * browser info session directories are now self-contained (may be put
  1231 on WWW server seperately); improved graphs of nested sessions; removed
  1232 graph for 'all sessions';
  1233 
  1234 * several improvements in isabelle style files; \isabellestyle{it}
  1235 produces fake math mode output; \isamarkupheader is now \section by
  1236 default; see lib/texinputs/isabelle.sty etc.;
  1237 
  1238 
  1239 *** Isar ***
  1240 
  1241 * Isar/Pure: local results and corresponding term bindings are now
  1242 subject to Hindley-Milner polymorphism (similar to ML); this
  1243 accommodates incremental type-inference very nicely;
  1244 
  1245 * Isar/Pure: new derived language element 'obtain' supports
  1246 generalized existence reasoning;
  1247 
  1248 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1249 support accumulation of results, without applying any rules yet;
  1250 useful to collect intermediate results without explicit name
  1251 references, and for use with transitivity rules with more than 2
  1252 premises;
  1253 
  1254 * Isar/Pure: scalable support for case-analysis type proofs: new
  1255 'case' language element refers to local contexts symbolically, as
  1256 produced by certain proof methods; internally, case names are attached
  1257 to theorems as "tags";
  1258 
  1259 * Isar/Pure: theory command 'hide' removes declarations from
  1260 class/type/const name spaces;
  1261 
  1262 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1263 indicate potential overloading;
  1264 
  1265 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1266 
  1267 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1268 "{a,b,c}" instead of {a,b,c};
  1269 
  1270 * Isar/Pure now provides its own version of intro/elim/dest
  1271 attributes; useful for building new logics, but beware of confusion
  1272 with the version in Provers/classical;
  1273 
  1274 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1275 case name 'antecedent';
  1276 
  1277 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1278 to the current context is now done automatically);
  1279 
  1280 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1281 for definining proof methods in ML;
  1282 
  1283 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1284 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1285 most cases, one should have to change intro!! to intro? only);
  1286 replaced "delrule" by "rule del";
  1287 
  1288 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1289 'symmetric' attribute (the latter supercedes [RS sym]);
  1290 
  1291 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1292 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1293 well (including splits);
  1294 
  1295 * Isar/Provers: Simplifier and Classical methods now support all kind
  1296 of modifiers used in the past, including 'cong', 'iff', etc.
  1297 
  1298 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1299 of Simplifier and Classical reasoner);
  1300 
  1301 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1302 now support named cases; major packages (inductive, datatype, primrec,
  1303 recdef) support case names and properly name parameters;
  1304 
  1305 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1306 monotonicity conditions are extracted to be proven at end of
  1307 calculations;
  1308 
  1309 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1310 method anyway;
  1311 
  1312 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1313 split_if split_if_asm; datatype package provides theorems foo.splits =
  1314 foo.split foo.split_asm for each datatype;
  1315 
  1316 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1317 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1318 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1319 use "(cases (simplified))" method in proper proof texts);
  1320 
  1321 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1322 
  1323 * Isar: names of theorems etc. may be natural numbers as well;
  1324 
  1325 * Isar: 'pr' command: optional arguments for goals_limit and
  1326 ProofContext.prems_limit; no longer prints theory contexts, but only
  1327 proof states;
  1328 
  1329 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1330 additional print modes to be specified; e.g. "pr(latex)" will print
  1331 proof state according to the Isabelle LaTeX style;
  1332 
  1333 * Isar: improved support for emulating tactic scripts, including proof
  1334 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1335 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1336 (for HOL datatypes);
  1337 
  1338 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1339 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1340 'proof method scripts' have to be in depth-first order;
  1341 
  1342 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1343 
  1344 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1345 should instead use individual commands for printing items
  1346 (print_commands, print_methods etc.);
  1347 
  1348 * Isar: added 'nothing' --- the empty list of theorems;
  1349 
  1350 
  1351 *** HOL ***
  1352 
  1353 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1354 corresponding virtual machine and a specification of its bytecode
  1355 verifier and a lightweight bytecode verifier, including proofs of
  1356 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1357 Cornelia Pusch (see also the homepage of project Bali at
  1358 http://isabelle.in.tum.de/Bali/);
  1359 
  1360 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1361 Clemens Ballarin;
  1362 
  1363 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1364 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1365 Rasmussen;
  1366 
  1367 * HOL/Lattice: fundamental concepts of lattice theory and order
  1368 structures, including duals, properties of bounds versus algebraic
  1369 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1370 Theorem for complete lattices etc.; may also serve as a demonstration
  1371 for abstract algebraic reasoning using axiomatic type classes, and
  1372 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1373 
  1374 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1375 von Oheimb;
  1376 
  1377 * HOL/IMPP: extension of IMP with local variables and mutually
  1378 recursive procedures, by David von Oheimb;
  1379 
  1380 * HOL/Lambda: converted into new-style theory and document;
  1381 
  1382 * HOL/ex/Multiquote: example of multiple nested quotations and
  1383 anti-quotations -- basically a generalized version of de-Bruijn
  1384 representation; very useful in avoiding lifting of operations;
  1385 
  1386 * HOL/record: added general record equality rule to simpset; fixed
  1387 select-update simplification procedure to handle extended records as
  1388 well; admit "r" as field name;
  1389 
  1390 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1391 other numeric types and also as the identity of groups, rings, etc.;
  1392 
  1393 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1394 Types nat and int belong to this axclass;
  1395 
  1396 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1397    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1398    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1399   two terms #m*u and #n*u are replaced by #(m+n)*u
  1400     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1401   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1402     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1403 
  1404 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1405 powerful prover for predicate logic but knows nothing of clasets; see
  1406 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1407 
  1408 * HOL: new version of "case_tac" subsumes both boolean case split and
  1409 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1410 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1411 
  1412 * HOL: simplification no longer dives into case-expressions: only the
  1413 selector expression is simplified, but not the remaining arms; to
  1414 enable full simplification of case-expressions for datatype t, you may
  1415 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1416 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1417 
  1418 * HOL/recdef: the recursion equations generated by 'recdef' for
  1419 function 'f' are now called f.simps instead of f.rules; if all
  1420 termination conditions are proved automatically, these simplification
  1421 rules are added to the simpset, as in primrec; rules may be named
  1422 individually as well, resulting in a separate list of theorems for
  1423 each equation;
  1424 
  1425 * HOL/While is a new theory that provides a while-combinator. It
  1426 permits the definition of tail-recursive functions without the
  1427 provision of a termination measure. The latter is necessary once the
  1428 invariant proof rule for while is applied.
  1429 
  1430 * HOL: new (overloaded) notation for the set of elements below/above
  1431 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1432 
  1433 * HOL: theorems impI, allI, ballI bound as "strip";
  1434 
  1435 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1436 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1437 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1438 
  1439 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1440 
  1441 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1442 main HOL, but was unused);
  1443 
  1444 * HOL: fewer consts declared as global (e.g. have to refer to
  1445 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1446 
  1447 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1448 in case of overlap with user translations (e.g. judgements over
  1449 tuples); (note that the underlying logical represenation is still
  1450 bogus);
  1451 
  1452 
  1453 *** ZF ***
  1454 
  1455 * ZF: simplification automatically cancels common terms in arithmetic
  1456 expressions over nat and int;
  1457 
  1458 * ZF: new treatment of nat to minimize type-checking: all operators
  1459 coerce their operands to a natural number using the function natify,
  1460 making the algebraic laws unconditional;
  1461 
  1462 * ZF: as above, for int: operators coerce their operands to an integer
  1463 using the function intify;
  1464 
  1465 * ZF: the integer library now contains many of the usual laws for the
  1466 orderings, including $<=, and monotonicity laws for $+ and $*;
  1467 
  1468 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1469 simplification;
  1470 
  1471 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1472 to the simplifier and classical reasoner simultaneously;
  1473 
  1474 
  1475 *** General ***
  1476 
  1477 * Provers: blast_tac now handles actual object-logic rules as
  1478 assumptions; note that auto_tac uses blast_tac internally as well;
  1479 
  1480 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1481 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1482 
  1483 * Provers: delrules now handles destruct rules as well (no longer need
  1484 explicit make_elim);
  1485 
  1486 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1487   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1488 use instead the strong form,
  1489   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1490 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1491 from destruct-rules;
  1492 
  1493 * Provers: Simplifier.easy_setup provides a fast path to basic
  1494 Simplifier setup for new object-logics;
  1495 
  1496 * Pure: AST translation rules no longer require constant head on LHS;
  1497 
  1498 * Pure: improved name spaces: ambiguous output is qualified; support
  1499 for hiding of names;
  1500 
  1501 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1502 XSYMBOL_HOME; no longer need to do manual configuration in most
  1503 situations;
  1504 
  1505 * system: compression of ML heaps images may now be controlled via -c
  1506 option of isabelle and isatool usedir (currently only observed by
  1507 Poly/ML);
  1508 
  1509 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1510 useful for remote X11);
  1511 
  1512 * system: provide TAGS file for Isabelle sources;
  1513 
  1514 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1515 order;
  1516 
  1517 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1518 timing flag supersedes proof_timing and Toplevel.trace;
  1519 
  1520 * ML: new combinators |>> and |>>> for incremental transformations
  1521 with secondary results (e.g. certain theory extensions):
  1522 
  1523 * ML: PureThy.add_defs gets additional argument to indicate potential
  1524 overloading (usually false);
  1525 
  1526 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1527 results;
  1528 
  1529 
  1530 
  1531 New in Isabelle99 (October 1999)
  1532 --------------------------------
  1533 
  1534 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1535 
  1536 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1537 are no longer simplified.  (This allows the simplifier to unfold recursive
  1538 functional programs.)  To restore the old behaviour, declare
  1539 
  1540     Delcongs [if_weak_cong];
  1541 
  1542 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1543 complement;
  1544 
  1545 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1546 
  1547 * HOL/datatype: mutual_induct_tac no longer exists --
  1548   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1549 
  1550 * HOL/typedef: fixed type inference for representing set; type
  1551 arguments now have to occur explicitly on the rhs as type constraints;
  1552 
  1553 * ZF: The con_defs part of an inductive definition may no longer refer
  1554 to constants declared in the same theory;
  1555 
  1556 * HOL, ZF: the function mk_cases, generated by the inductive
  1557 definition package, has lost an argument.  To simplify its result, it
  1558 uses the default simpset instead of a supplied list of theorems.
  1559 
  1560 * HOL/List: the constructors of type list are now Nil and Cons;
  1561 
  1562 * Simplifier: the type of the infix ML functions
  1563         setSSolver addSSolver setSolver addSolver
  1564 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1565 for packaging solvers. A solver is created via
  1566         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1567 where the string argument is only a comment.
  1568 
  1569 
  1570 *** Proof tools ***
  1571 
  1572 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1573 decision procedure for linear arithmetic. Currently it is used for
  1574 types `nat', `int', and `real' in HOL (see below); it can, should and
  1575 will be instantiated for other types and logics as well.
  1576 
  1577 * The simplifier now accepts rewrite rules with flexible heads, eg
  1578      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1579   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1580   matching.
  1581 
  1582 
  1583 *** General ***
  1584 
  1585 * New Isabelle/Isar subsystem provides an alternative to traditional
  1586 tactical theorem proving; together with the ProofGeneral/isar user
  1587 interface it offers an interactive environment for developing human
  1588 readable proof documents (Isar == Intelligible semi-automated
  1589 reasoning); for further information see isatool doc isar-ref,
  1590 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1591 
  1592 * improved and simplified presentation of theories: better HTML markup
  1593 (including colors), graph views in several sizes; isatool usedir now
  1594 provides a proper interface for user theories (via -P option); actual
  1595 document preparation based on (PDF)LaTeX is available as well (for
  1596 new-style theories only); see isatool doc system for more information;
  1597 
  1598 * native support for Proof General, both for classic Isabelle and
  1599 Isabelle/Isar;
  1600 
  1601 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1602 using the graph browser tool;
  1603 
  1604 * Isabelle manuals now also available as PDF;
  1605 
  1606 * theory loader rewritten from scratch (may not be fully
  1607 bug-compatible); old loadpath variable has been replaced by show_path,
  1608 add_path, del_path, reset_path functions; new operations such as
  1609 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1610 isatool doc ref);
  1611 
  1612 * improved isatool install: option -k creates KDE application icon,
  1613 option -p DIR installs standalone binaries;
  1614 
  1615 * added ML_PLATFORM setting (useful for cross-platform installations);
  1616 more robust handling of platform specific ML images for SML/NJ;
  1617 
  1618 * the settings environment is now statically scoped, i.e. it is never
  1619 created again in sub-processes invoked from isabelle, isatool, or
  1620 Isabelle;
  1621 
  1622 * path element specification '~~' refers to '$ISABELLE_HOME';
  1623 
  1624 * in locales, the "assumes" and "defines" parts may be omitted if
  1625 empty;
  1626 
  1627 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1628 long arrows);
  1629 
  1630 * new print_mode "HTML";
  1631 
  1632 * new flag show_tags controls display of tags of theorems (which are
  1633 basically just comments that may be attached by some tools);
  1634 
  1635 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1636 mode and goal output format:
  1637 
  1638 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1639 244c244
  1640 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1641 ---
  1642 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1643 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1644 181c181
  1645 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1646 ---
  1647 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1648 
  1649 * function bind_thms stores lists of theorems (cf. bind_thm);
  1650 
  1651 * new shorthand tactics ftac, eatac, datac, fatac;
  1652 
  1653 * qed (and friends) now accept "" as result name; in that case the
  1654 theorem is not stored, but proper checks and presentation of the
  1655 result still apply;
  1656 
  1657 * theorem database now also indexes constants "Trueprop", "all",
  1658 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1659 
  1660 
  1661 *** HOL ***
  1662 
  1663 ** HOL arithmetic **
  1664 
  1665 * There are now decision procedures for linear arithmetic over nat and
  1666 int:
  1667 
  1668 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1669 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1670 are treated as atomic; subformulae not involving type `nat' or `int'
  1671 are ignored; quantified subformulae are ignored unless they are
  1672 positive universal or negative existential. The tactic has to be
  1673 invoked by hand and can be a little bit slow. In particular, the
  1674 running time is exponential in the number of occurrences of `min' and
  1675 `max', and `-' on `nat'.
  1676 
  1677 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1678 (negated) (in)equalities among the premises and the conclusion into
  1679 account (i.e. no compound formulae) and does not know about `min' and
  1680 `max', and `-' on `nat'. It is fast and is used automatically by the
  1681 simplifier.
  1682 
  1683 NB: At the moment, these decision procedures do not cope with mixed
  1684 nat/int formulae where the two parts interact, such as `m < n ==>
  1685 int(m) < int(n)'.
  1686 
  1687 * HOL/Numeral provides a generic theory of numerals (encoded
  1688 efficiently as bit strings); setup for types nat/int/real is in place;
  1689 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1690 int, existing theories and proof scripts may require a few additional
  1691 type constraints;
  1692 
  1693 * integer division and remainder can now be performed on constant
  1694 arguments;
  1695 
  1696 * many properties of integer multiplication, division and remainder
  1697 are now available;
  1698 
  1699 * An interface to the Stanford Validity Checker (SVC) is available through the
  1700 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1701 are proved automatically.  SVC must be installed separately, and its results
  1702 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1703 invocation of the underlying oracle).  For SVC see
  1704   http://verify.stanford.edu/SVC
  1705 
  1706 * IsaMakefile: the HOL-Real target now builds an actual image;
  1707 
  1708 
  1709 ** HOL misc **
  1710 
  1711 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1712 (in Isabelle/Isar) -- by Gertrud Bauer;
  1713 
  1714 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1715 analysis for assembly languages with subtypes;
  1716 
  1717 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1718 -- avoids syntactic ambiguities and treats state, transition, and
  1719 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1720 changed syntax and (many) tactics;
  1721 
  1722 * HOL/inductive: Now also handles more general introduction rules such
  1723   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1724   theorems are now maintained within the theory (maintained via the
  1725   "mono" attribute);
  1726 
  1727 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1728   (using function types) such as
  1729 
  1730   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1731 
  1732 * HOL/record: record_simproc (part of the default simpset) takes care
  1733 of selectors applied to updated records; record_split_tac is no longer
  1734 part of the default claset; update_defs may now be removed from the
  1735 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1736 
  1737   claset_ref () := claset() addSWrapper record_split_wrapper;
  1738   Delsimprocs [record_simproc]
  1739 
  1740 * HOL/typedef: fixed type inference for representing set; type
  1741 arguments now have to occur explicitly on the rhs as type constraints;
  1742 
  1743 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1744 names rather than an ML expression;
  1745 
  1746 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1747 supplied later.  Program schemes can be defined, such as
  1748     "While B C s = (if B s then While B C (C s) else s)"
  1749 where the well-founded relation can be chosen after B and C have been given.
  1750 
  1751 * HOL/List: the constructors of type list are now Nil and Cons;
  1752 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1753 course, ML tools referring to List.list.op # etc. have to be adapted;
  1754 
  1755 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1756 disabled by default; run isabelle with option -m HOL to get back to
  1757 the original Gordon/HOL-style output;
  1758 
  1759 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1760 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1761 
  1762 * HOL basic syntax simplified (more orthogonal): all variants of
  1763 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1764 Eps operator is provided as well: "SOME x. P[x]";
  1765 
  1766 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1767 
  1768 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1769 thus available for user theories;
  1770 
  1771 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1772 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1773 time;
  1774 
  1775 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1776 several times and then mp;
  1777 
  1778 
  1779 *** LK ***
  1780 
  1781 * the notation <<...>> is now available as a notation for sequences of
  1782 formulas;
  1783 
  1784 * the simplifier is now installed
  1785 
  1786 * the axiom system has been generalized (thanks to Soren Heilmann)
  1787 
  1788 * the classical reasoner now has a default rule database
  1789 
  1790 
  1791 *** ZF ***
  1792 
  1793 * new primrec section allows primitive recursive functions to be given
  1794 directly (as in HOL) over datatypes and the natural numbers;
  1795 
  1796 * new tactics induct_tac and exhaust_tac for induction (or case
  1797 analysis) over datatypes and the natural numbers;
  1798 
  1799 * the datatype declaration of type T now defines the recursor T_rec;
  1800 
  1801 * simplification automatically does freeness reasoning for datatype
  1802 constructors;
  1803 
  1804 * automatic type-inference, with AddTCs command to insert new
  1805 type-checking rules;
  1806 
  1807 * datatype introduction rules are now added as Safe Introduction rules
  1808 to the claset;
  1809 
  1810 * the syntax "if P then x else y" is now available in addition to
  1811 if(P,x,y);
  1812 
  1813 
  1814 *** Internal programming interfaces ***
  1815 
  1816 * tuned simplifier trace output; new flag debug_simp;
  1817 
  1818 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1819 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1820 
  1821 * AxClass.axclass_tac lost the theory argument;
  1822 
  1823 * tuned current_goals_markers semantics: begin / end goal avoids
  1824 printing empty lines;
  1825 
  1826 * removed prs and prs_fn hook, which was broken because it did not
  1827 include \n in its semantics, forcing writeln to add one
  1828 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1829 string -> unit if you really want to output text without newline;
  1830 
  1831 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1832 plain output, interface builders may have to enable 'isabelle_font'
  1833 mode to get Isabelle font glyphs as before;
  1834 
  1835 * refined token_translation interface; INCOMPATIBILITY: output length
  1836 now of type real instead of int;
  1837 
  1838 * theory loader actions may be traced via new ThyInfo.add_hook
  1839 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1840 your own database of information attached to *whole* theories -- as
  1841 opposed to intra-theory data slots offered via TheoryDataFun;
  1842 
  1843 * proper handling of dangling sort hypotheses (at last!);
  1844 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1845 extra sort hypotheses that can be witnessed from the type signature;
  1846 the force_strip_shyps flag is gone, any remaining shyps are simply
  1847 left in the theorem (with a warning issued by strip_shyps_warning);
  1848 
  1849 
  1850 
  1851 New in Isabelle98-1 (October 1998)
  1852 ----------------------------------
  1853 
  1854 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1855 
  1856 * several changes of automated proof tools;
  1857 
  1858 * HOL: major changes to the inductive and datatype packages, including
  1859 some minor incompatibilities of theory syntax;
  1860 
  1861 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1862 called `inj_on';
  1863 
  1864 * HOL: removed duplicate thms in Arith:
  1865   less_imp_add_less  should be replaced by  trans_less_add1
  1866   le_imp_add_le      should be replaced by  trans_le_add1
  1867 
  1868 * HOL: unary minus is now overloaded (new type constraints may be
  1869 required);
  1870 
  1871 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1872 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1873 now taken as an integer constant.
  1874 
  1875 * Pure: ML function 'theory_of' renamed to 'theory';
  1876 
  1877 
  1878 *** Proof tools ***
  1879 
  1880 * Simplifier:
  1881   1. Asm_full_simp_tac is now more aggressive.
  1882      1. It will sometimes reorient premises if that increases their power to
  1883         simplify.
  1884      2. It does no longer proceed strictly from left to right but may also
  1885         rotate premises to achieve further simplification.
  1886      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1887      old Asm_full_simp_tac in that it does not rotate premises.
  1888   2. The simplifier now knows a little bit about nat-arithmetic.
  1889 
  1890 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1891 allows for selected deletion of wrappers, by introduction of names for
  1892 wrapper functionals.  This implies that addbefore, addSbefore,
  1893 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1894 and that adding two tactics with the same name overwrites the first
  1895 one (emitting a warning).
  1896   type wrapper = (int -> tactic) -> (int -> tactic)
  1897   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1898   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1899   delWrapper, delSWrapper: claset *  string            -> claset
  1900   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1901 
  1902 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1903 semantics; addbefore now affects only the unsafe part of step_tac
  1904 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1905 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1906 by Force_tac;
  1907 
  1908 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1909 compWrapper; added safe wrapper (and access functions for it);
  1910 
  1911 * HOL/split_all_tac is now much faster and fails if there is nothing
  1912 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1913 and the names of the automatically generated variables have changed.
  1914 split_all_tac has moved within claset() from unsafe wrappers to safe
  1915 wrappers, which means that !!-bound variables are split much more
  1916 aggressively, and safe_tac and clarify_tac now split such variables.
  1917 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1918 Note: the same holds for record_split_tac, which does the job of
  1919 split_all_tac for record fields.
  1920 
  1921 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1922 permanently to the default simpset using Addsplits just like
  1923 Addsimps. They can be removed via Delsplits just like
  1924 Delsimps. Lower-case versions are also available.
  1925 
  1926 * HOL/Simplifier: The rule split_if is now part of the default
  1927 simpset. This means that the simplifier will eliminate all occurrences
  1928 of if-then-else in the conclusion of a goal. To prevent this, you can
  1929 either remove split_if completely from the default simpset by
  1930 `Delsplits [split_if]' or remove it in a specific call of the
  1931 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1932 other case splitting rules to/from the default simpset: every datatype
  1933 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1934 t is the name of the datatype).
  1935 
  1936 * Classical reasoner / Simplifier combination: new force_tac (and
  1937 derivatives Force_tac, force) combines rewriting and classical
  1938 reasoning (and whatever other tools) similarly to auto_tac, but is
  1939 aimed to solve the given subgoal completely.
  1940 
  1941 
  1942 *** General ***
  1943 
  1944 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1945 and `goalw': the theory is no longer needed as an explicit argument -
  1946 the current theory context is used; assumptions are no longer returned
  1947 at the ML-level unless one of them starts with ==> or !!; it is
  1948 recommended to convert to these new commands using isatool fixgoal
  1949 (backup your sources first!);
  1950 
  1951 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1952 the current theory context, and 'theory' to lookup stored theories;
  1953 
  1954 * new theory section 'locale' for declaring constants, assumptions and
  1955 definitions that have local scope;
  1956 
  1957 * new theory section 'nonterminals' for purely syntactic types;
  1958 
  1959 * new theory section 'setup' for generic ML setup functions
  1960 (e.g. package initialization);
  1961 
  1962 * the distribution now includes Isabelle icons: see
  1963 lib/logo/isabelle-{small,tiny}.xpm;
  1964 
  1965 * isatool install - install binaries with absolute references to
  1966 ISABELLE_HOME/bin;
  1967 
  1968 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1969 
  1970 * print mode 'emacs' reserved for Isamode;
  1971 
  1972 * support multiple print (ast) translations per constant name;
  1973 
  1974 * theorems involving oracles are now printed with a suffixed [!];
  1975 
  1976 
  1977 *** HOL ***
  1978 
  1979 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1980 
  1981 * HOL/inductive package reorganized and improved: now supports mutual
  1982 definitions such as
  1983 
  1984   inductive EVEN ODD
  1985     intrs
  1986       null "0 : EVEN"
  1987       oddI "n : EVEN ==> Suc n : ODD"
  1988       evenI "n : ODD ==> Suc n : EVEN"
  1989 
  1990 new theorem list "elims" contains an elimination rule for each of the
  1991 recursive sets; inductive definitions now handle disjunctive premises
  1992 correctly (also ZF);
  1993 
  1994 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1995 "mutual_induct" no longer exists - the induction rule is always
  1996 contained in "induct";
  1997 
  1998 
  1999 * HOL/datatype package re-implemented and greatly improved: now
  2000 supports mutually recursive datatypes such as
  2001 
  2002   datatype
  2003     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2004             | SUM ('a aexp) ('a aexp)
  2005             | DIFF ('a aexp) ('a aexp)
  2006             | NUM 'a
  2007   and
  2008     'a bexp = LESS ('a aexp) ('a aexp)
  2009             | AND ('a bexp) ('a bexp)
  2010             | OR ('a bexp) ('a bexp)
  2011 
  2012 as well as indirectly recursive datatypes such as
  2013 
  2014   datatype
  2015     ('a, 'b) term = Var 'a
  2016                   | App 'b ((('a, 'b) term) list)
  2017 
  2018 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2019 induction on mutually / indirectly recursive datatypes.
  2020 
  2021 Primrec equations are now stored in theory and can be accessed via
  2022 <function_name>.simps.
  2023 
  2024 INCOMPATIBILITIES:
  2025 
  2026   - Theories using datatypes must now have theory Datatype as an
  2027     ancestor.
  2028   - The specific <typename>.induct_tac no longer exists - use the
  2029     generic induct_tac instead.
  2030   - natE has been renamed to nat.exhaust - use exhaust_tac
  2031     instead of res_inst_tac ... natE. Note that the variable
  2032     names in nat.exhaust differ from the names in natE, this
  2033     may cause some "fragile" proofs to fail.
  2034   - The theorems split_<typename>_case and split_<typename>_case_asm
  2035     have been renamed to <typename>.split and <typename>.split_asm.
  2036   - Since default sorts of type variables are now handled correctly,
  2037     some datatype definitions may have to be annotated with explicit
  2038     sort constraints.
  2039   - Primrec definitions no longer require function name and type
  2040     of recursive argument.
  2041 
  2042 Consider using isatool fixdatatype to adapt your theories and proof
  2043 scripts to the new package (backup your sources first!).
  2044 
  2045 
  2046 * HOL/record package: considerably improved implementation; now
  2047 includes concrete syntax for record types, terms, updates; theorems
  2048 for surjective pairing and splitting !!-bound record variables; proof
  2049 support is as follows:
  2050 
  2051   1) standard conversions (selectors or updates applied to record
  2052 constructor terms) are part of the standard simpset;
  2053 
  2054   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2055 made part of standard simpset and claset via addIffs;
  2056 
  2057   3) a tactic for record field splitting (record_split_tac) is part of
  2058 the standard claset (addSWrapper);
  2059 
  2060 To get a better idea about these rules you may retrieve them via
  2061 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2062 the name of your record type.
  2063 
  2064 The split tactic 3) conceptually simplifies by the following rule:
  2065 
  2066   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2067 
  2068 Thus any record variable that is bound by meta-all will automatically
  2069 blow up into some record constructor term, consequently the
  2070 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2071 solve record problems automatically.
  2072 
  2073 
  2074 * reorganized the main HOL image: HOL/Integ and String loaded by
  2075 default; theory Main includes everything;
  2076 
  2077 * automatic simplification of integer sums and comparisons, using cancellation;
  2078 
  2079 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2080 
  2081 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2082 
  2083 * many new identities for unions, intersections, set difference, etc.;
  2084 
  2085 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2086 called split_if, split_split, split_sum_case and split_nat_case (to go
  2087 with add/delsplits);
  2088 
  2089 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2090 (?x::unit) = (); this is made part of the default simpset, which COULD
  2091 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2092 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2093 unit_abs_eta_conv is added in order to counter the effect of
  2094 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2095 %u.f();
  2096 
  2097 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2098 makes more sense);
  2099 
  2100 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2101   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2102   disjointness reasoning but breaking a few old proofs.
  2103 
  2104 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2105 to 'converse' from 'inverse' (for compatibility with ZF and some
  2106 literature);
  2107 
  2108 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2109 the well-founded relation;
  2110 
  2111 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2112     Compl A.  The "Compl" syntax remains available as input syntax for this
  2113     release ONLY.
  2114 
  2115 * HOL/Update: new theory of function updates:
  2116     f(a:=b) == %x. if x=a then b else f x
  2117 may also be iterated as in f(a:=b,c:=d,...);
  2118 
  2119 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2120 
  2121 * HOL/List:
  2122   - new function list_update written xs[i:=v] that updates the i-th
  2123     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2124   - new function `upt' written [i..j(] which generates the list
  2125     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2126     bound write [i..j], which is a shorthand for [i..j+1(].
  2127   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2128 
  2129 * HOL/Arith:
  2130   - removed 'pred' (predecessor) function;
  2131   - generalized some theorems about n-1;
  2132   - many new laws about "div" and "mod";
  2133   - new laws about greatest common divisors (see theory ex/Primes);
  2134 
  2135 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2136 instead of "inverse";
  2137 
  2138 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2139   of the multiset ordering;
  2140 
  2141 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2142   (not included by default);
  2143 
  2144 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2145 
  2146 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2147   programs, i.e. different program variables may have different types.
  2148 
  2149 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2150   [previously, this check worked only if the rewrite rule was unconditional]
  2151   Now rew can involve either definitions or equalities (either == or =).
  2152 
  2153 
  2154 *** ZF ***
  2155 
  2156 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2157   only the theorems proved on ZF.ML;
  2158 
  2159 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2160   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2161   disjointness reasoning but breaking a few old proofs.
  2162 
  2163 * ZF/Update: new theory of function updates
  2164     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2165   may also be iterated as in f(a:=b,c:=d,...);
  2166 
  2167 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2168 
  2169 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2170   [previously, this check worked only if the rewrite rule was unconditional]
  2171   Now rew can involve either definitions or equalities (either == or =).
  2172 
  2173 * case_tac provided for compatibility with HOL
  2174     (like the old excluded_middle_tac, but with subgoals swapped)
  2175 
  2176 
  2177 *** Internal programming interfaces ***
  2178 
  2179 * Pure: several new basic modules made available for general use, see
  2180 also src/Pure/README;
  2181 
  2182 * improved the theory data mechanism to support encapsulation (data
  2183 kind name replaced by private Object.kind, acting as authorization
  2184 key); new type-safe user interface via functor TheoryDataFun; generic
  2185 print_data function becomes basically useless;
  2186 
  2187 * removed global_names compatibility flag -- all theory declarations
  2188 are qualified by default;
  2189 
  2190 * module Pure/Syntax now offers quote / antiquote translation
  2191 functions (useful for Hoare logic etc. with implicit dependencies);
  2192 see HOL/ex/Antiquote for an example use;
  2193 
  2194 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2195 cterm -> thm;
  2196 
  2197 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2198 subgoal;
  2199 
  2200 * Display.print_goals function moved to Locale.print_goals;
  2201 
  2202 * standard print function for goals supports current_goals_markers
  2203 variable for marking begin of proof, end of proof, start of goal; the
  2204 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2205 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2206 for example;
  2207 
  2208 
  2209 
  2210 New in Isabelle98 (January 1998)
  2211 --------------------------------
  2212 
  2213 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2214 
  2215 * changed lexical syntax of terms / types: dots made part of long
  2216 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2217 
  2218 * simpset (and claset) reference variable replaced by functions
  2219 simpset / simpset_ref;
  2220 
  2221 * no longer supports theory aliases (via merge) and non-trivial
  2222 implicit merge of thms' signatures;
  2223 
  2224 * most internal names of constants changed due to qualified names;
  2225 
  2226 * changed Pure/Sequence interface (see Pure/seq.ML);
  2227 
  2228 
  2229 *** General Changes ***
  2230 
  2231 * hierachically structured name spaces (for consts, types, axms, thms
  2232 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2233 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2234 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2235 long_names for fully qualified output names; NOTE: ML programs
  2236 (special tactics, packages etc.) referring to internal names may have
  2237 to be adapted to cope with fully qualified names; in case of severe
  2238 backward campatibility problems try setting 'global_names' at compile
  2239 time to have enrything declared within a flat name space; one may also
  2240 fine tune name declarations in theories via the 'global' and 'local'
  2241 section;
  2242 
  2243 * reimplemented the implicit simpset and claset using the new anytype
  2244 data filed in signatures; references simpset:simpset ref etc. are
  2245 replaced by functions simpset:unit->simpset and
  2246 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2247 to patch your ML files accordingly;
  2248 
  2249 * HTML output now includes theory graph data for display with Java
  2250 applet or isatool browser; data generated automatically via isatool
  2251 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2252 
  2253 * defs may now be conditional; improved rewrite_goals_tac to handle
  2254 conditional equations;
  2255 
  2256 * defs now admits additional type arguments, using TYPE('a) syntax;
  2257 
  2258 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2259 creates a new theory node; implicit merge of thms' signatures is
  2260 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2261 transfer:theory->thm->thm in (rare) cases;
  2262 
  2263 * improved handling of draft signatures / theories; draft thms (and
  2264 ctyps, cterms) are automatically promoted to real ones;
  2265 
  2266 * slightly changed interfaces for oracles: admit many per theory, named
  2267 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2268 
  2269 * print_goals: optional output of const types (set show_consts and
  2270 show_types);
  2271 
  2272 * improved output of warnings (###) and errors (***);
  2273 
  2274 * subgoal_tac displays a warning if the new subgoal has type variables;
  2275 
  2276 * removed old README and Makefiles;
  2277 
  2278 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2279 
  2280 * removed obsolete init_pps and init_database;
  2281 
  2282 * deleted the obsolete tactical STATE, which was declared by
  2283     fun STATE tacfun st = tacfun st st;
  2284 
  2285 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2286 (which abbreviates $HOME);
  2287 
  2288 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2289 use isatool fixseq to adapt your ML programs (this works for fully
  2290 qualified references to the Sequence structure only!);
  2291 
  2292 * use_thy no longer requires writable current directory; it always
  2293 reloads .ML *and* .thy file, if either one is out of date;
  2294 
  2295 
  2296 *** Classical Reasoner ***
  2297 
  2298 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2299 tactics that use classical reasoning to simplify a subgoal without
  2300 splitting it into several subgoals;
  2301 
  2302 * Safe_tac: like safe_tac but uses the default claset;
  2303 
  2304 
  2305 *** Simplifier ***
  2306 
  2307 * added simplification meta rules:
  2308     (asm_)(full_)simplify: simpset -> thm -> thm;
  2309 
  2310 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2311 logics (again);
  2312 
  2313 * added prems argument to simplification procedures;
  2314 
  2315 * HOL, FOL, ZF: added infix function `addsplits':
  2316   instead of `<simpset> setloop (split_tac <thms>)'
  2317   you can simply write `<simpset> addsplits <thms>'
  2318 
  2319 
  2320 *** Syntax ***
  2321 
  2322 * TYPE('a) syntax for type reflection terms;
  2323 
  2324 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2325 
  2326 * pretty printer: changed order of mixfix annotation preference (again!);
  2327 
  2328 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2329 
  2330 
  2331 *** HOL ***
  2332 
  2333 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2334   with `addloop' of the simplifier to faciliate case splitting in premises.
  2335 
  2336 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2337 
  2338 * HOL/Auth: new protocol proofs including some for the Internet
  2339   protocol TLS;
  2340 
  2341 * HOL/Map: new theory of `maps' a la VDM;
  2342 
  2343 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2344 cancelling out common nat summands from =, <, <= (in)equalities, or
  2345 differences; simplification procedures nat_cancel_factor for
  2346 cancelling common factor from =, <, <= (in)equalities over natural
  2347 sums; nat_cancel contains both kinds of procedures, it is installed by
  2348 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2349 
  2350 * HOL/simplifier: terms of the form
  2351   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2352   are rewritten to
  2353   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2354   and those of the form
  2355   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2356   are rewritten to
  2357   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2358 
  2359 * HOL/datatype
  2360   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2361 
  2362   P(t_case f1 ... fn x) =
  2363      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2364         ...
  2365        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2366      )
  2367 
  2368   and a theorem `split_t_case_asm' of the form
  2369 
  2370   P(t_case f1 ... fn x) =
  2371     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2372         ...
  2373        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2374      )
  2375   which can be added to a simpset via `addsplits'. The existing theorems
  2376   expand_list_case and expand_option_case have been renamed to
  2377   split_list_case and split_option_case.
  2378 
  2379 * HOL/Arithmetic:
  2380   - `pred n' is automatically converted to `n-1'.
  2381     Users are strongly encouraged not to use `pred' any longer,
  2382     because it will disappear altogether at some point.
  2383   - Users are strongly encouraged to write "0 < n" rather than
  2384     "n ~= 0". Theorems and proof tools have been modified towards this
  2385     `standard'.
  2386 
  2387 * HOL/Lists:
  2388   the function "set_of_list" has been renamed "set" (and its theorems too);
  2389   the function "nth" now takes its arguments in the reverse order and
  2390   has acquired the infix notation "!" as in "xs!n".
  2391 
  2392 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2393 
  2394 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2395   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2396 
  2397 * HOL/record: extensible records with schematic structural subtyping
  2398 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2399 still lacks various theorems and concrete record syntax;
  2400 
  2401 
  2402 *** HOLCF ***
  2403 
  2404 * removed "axioms" and "generated by" sections;
  2405 
  2406 * replaced "ops" section by extended "consts" section, which is capable of
  2407   handling the continuous function space "->" directly;
  2408 
  2409 * domain package:
  2410   . proves theorems immediately and stores them in the theory,
  2411   . creates hierachical name space,
  2412   . now uses normal mixfix annotations (instead of cinfix...),
  2413   . minor changes to some names and values (for consistency),
  2414   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2415   . separator between mutual domain defs: changed "," to "and",
  2416   . improved handling of sort constraints;  now they have to
  2417     appear on the left-hand side of the equations only;
  2418 
  2419 * fixed LAM <x,y,zs>.b syntax;
  2420 
  2421 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2422 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2423 
  2424 
  2425 *** FOL and ZF ***
  2426 
  2427 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2428   with `addloop' of the simplifier to faciliate case splitting in premises.
  2429 
  2430 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2431 in HOL, they strip ALL and --> from proved theorems;
  2432 
  2433 
  2434 
  2435 New in Isabelle94-8 (May 1997)
  2436 ------------------------------
  2437 
  2438 *** General Changes ***
  2439 
  2440 * new utilities to build / run / maintain Isabelle etc. (in parts
  2441 still somewhat experimental); old Makefiles etc. still functional;
  2442 
  2443 * new 'Isabelle System Manual';
  2444 
  2445 * INSTALL text, together with ./configure and ./build scripts;
  2446 
  2447 * reimplemented type inference for greater efficiency, better error
  2448 messages and clean internal interface;
  2449 
  2450 * prlim command for dealing with lots of subgoals (an easier way of
  2451 setting goals_limit);
  2452 
  2453 
  2454 *** Syntax ***
  2455 
  2456 * supports alternative (named) syntax tables (parser and pretty
  2457 printer); internal interface is provided by add_modesyntax(_i);
  2458 
  2459 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2460 be used in conjunction with the Isabelle symbol font; uses the
  2461 "symbols" syntax table;
  2462 
  2463 * added token_translation interface (may translate name tokens in
  2464 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2465 the current print_mode); IMPORTANT: user print translation functions
  2466 are responsible for marking newly introduced bounds
  2467 (Syntax.mark_boundT);
  2468 
  2469 * token translations for modes "xterm" and "xterm_color" that display
  2470 names in bold, underline etc. or colors (which requires a color
  2471 version of xterm);
  2472 
  2473 * infixes may now be declared with names independent of their syntax;
  2474 
  2475 * added typed_print_translation (like print_translation, but may
  2476 access type of constant);
  2477 
  2478 
  2479 *** Classical Reasoner ***
  2480 
  2481 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2482 some limitations.  Blast_tac...
  2483   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2484   + ignores elimination rules that don't have the correct format
  2485         (the conclusion MUST be a formula variable)
  2486   + ignores types, which can make HOL proofs fail
  2487   + rules must not require higher-order unification, e.g. apply_type in ZF
  2488     [message "Function Var's argument not a bound variable" relates to this]
  2489   + its proof strategy is more general but can actually be slower
  2490 
  2491 * substitution with equality assumptions no longer permutes other
  2492 assumptions;
  2493 
  2494 * minor changes in semantics of addafter (now called addaltern); renamed
  2495 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2496 (and access functions for it);
  2497 
  2498 * improved combination of classical reasoner and simplifier:
  2499   + functions for handling clasimpsets
  2500   + improvement of addss: now the simplifier is called _after_ the
  2501     safe steps.
  2502   + safe variant of addss called addSss: uses safe simplifications
  2503     _during_ the safe steps. It is more complete as it allows multiple
  2504     instantiations of unknowns (e.g. with slow_tac).
  2505 
  2506 *** Simplifier ***
  2507 
  2508 * added interface for simplification procedures (functions that
  2509 produce *proven* rewrite rules on the fly, depending on current
  2510 redex);
  2511 
  2512 * ordering on terms as parameter (used for ordered rewriting);
  2513 
  2514 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2515 
  2516 * the solver is now split into a safe and an unsafe part.
  2517 This should be invisible for the normal user, except that the
  2518 functions setsolver and addsolver have been renamed to setSolver and
  2519 addSolver; added safe_asm_full_simp_tac;
  2520 
  2521 
  2522 *** HOL ***
  2523 
  2524 * a generic induction tactic `induct_tac' which works for all datatypes and
  2525 also for type `nat';
  2526 
  2527 * a generic case distinction tactic `exhaust_tac' which works for all
  2528 datatypes and also for type `nat';
  2529 
  2530 * each datatype comes with a function `size';
  2531 
  2532 * patterns in case expressions allow tuple patterns as arguments to
  2533 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2534 
  2535 * primrec now also works with type nat;
  2536 
  2537 * recdef: a new declaration form, allows general recursive functions to be
  2538 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2539 
  2540 * the constant for negation has been renamed from "not" to "Not" to
  2541 harmonize with FOL, ZF, LK, etc.;
  2542 
  2543 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2544 infinite lists;
  2545 
  2546 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2547 
  2548 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2549 problems in commutative rings, using axiomatic type classes for + and *;
  2550 
  2551 * more examples in HOL/MiniML and HOL/Auth;
  2552 
  2553 * more default rewrite rules for quantifiers, union/intersection;
  2554 
  2555 * a new constant `arbitrary == @x.False';
  2556 
  2557 * HOLCF/IOA replaces old HOL/IOA;
  2558 
  2559 * HOLCF changes: derived all rules and arities
  2560   + axiomatic type classes instead of classes
  2561   + typedef instead of faking type definitions
  2562   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2563   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2564   + eliminated the types void, one, tr
  2565   + use unit lift and bool lift (with translations) instead of one and tr
  2566   + eliminated blift from Lift3.thy (use Def instead of blift)
  2567   all eliminated rules are derived as theorems --> no visible changes ;
  2568 
  2569 
  2570 *** ZF ***
  2571 
  2572 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2573 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2574 as ZF_cs addSIs [equalityI];
  2575 
  2576 
  2577 
  2578 New in Isabelle94-7 (November 96)
  2579 ---------------------------------
  2580 
  2581 * allowing negative levels (as offsets) in prlev and choplev;
  2582 
  2583 * super-linear speedup for large simplifications;
  2584 
  2585 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2586 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2587 FAIL); can suppress it using the command Delsimps (ex_simps @
  2588 all_simps); De Morgan laws are also now included, by default;
  2589 
  2590 * improved printing of ==>  :  ~:
  2591 
  2592 * new object-logic "Sequents" adds linear logic, while replacing LK
  2593 and Modal (thanks to Sara Kalvala);
  2594 
  2595 * HOL/Auth: correctness proofs for authentication protocols;
  2596 
  2597 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2598 examples on HOL/Auth);
  2599 
  2600 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2601 the rewriter and classical reasoner simultaneously;
  2602 
  2603 * function uresult no longer returns theorems in "standard" format;
  2604 regain previous version by: val uresult = standard o uresult;
  2605 
  2606 
  2607 
  2608 New in Isabelle94-6
  2609 -------------------
  2610 
  2611 * oracles -- these establish an interface between Isabelle and trusted
  2612 external reasoners, which may deliver results as theorems;
  2613 
  2614 * proof objects (in particular record all uses of oracles);
  2615 
  2616 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2617 
  2618 * "constdefs" section in theory files;
  2619 
  2620 * "primrec" section (HOL) no longer requires names;
  2621 
  2622 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2623 
  2624 
  2625 
  2626 New in Isabelle94-5
  2627 -------------------
  2628 
  2629 * reduced space requirements;
  2630 
  2631 * automatic HTML generation from theories;
  2632 
  2633 * theory files no longer require "..." (quotes) around most types;
  2634 
  2635 * new examples, including two proofs of the Church-Rosser theorem;
  2636 
  2637 * non-curried (1994) version of HOL is no longer distributed;
  2638 
  2639 
  2640 
  2641 New in Isabelle94-4
  2642 -------------------
  2643 
  2644 * greatly reduced space requirements;
  2645 
  2646 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2647 
  2648 * searchable theorem database (see the section "Retrieving theorems" on
  2649 page 8 of the Reference Manual);
  2650 
  2651 * new examples, including Grabczewski's monumental case study of the
  2652 Axiom of Choice;
  2653 
  2654 * The previous version of HOL renamed to Old_HOL;
  2655 
  2656 * The new version of HOL (previously called CHOL) uses a curried syntax
  2657 for functions.  Application looks like f a b instead of f(a,b);
  2658 
  2659 * Mutually recursive inductive definitions finally work in HOL;
  2660 
  2661 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2662 translates to the operator "split";
  2663 
  2664 
  2665 
  2666 New in Isabelle94-3
  2667 -------------------
  2668 
  2669 * new infix operator, addss, allowing the classical reasoner to
  2670 perform simplification at each step of its search.  Example:
  2671         fast_tac (cs addss ss)
  2672 
  2673 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2674 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2675 look like (a,b) instead of <a,b>;
  2676 
  2677 * PLEASE NOTE: CHOL will eventually replace HOL!
  2678 
  2679 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2680 It translates to the operator "split".  A new theory of integers is available;
  2681 
  2682 * In ZF, integer numerals now denote two's-complement binary integers.
  2683 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2684 
  2685 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2686 of the Axiom of Choice;
  2687 
  2688 
  2689 
  2690 New in Isabelle94-2
  2691 -------------------
  2692 
  2693 * Significantly faster resolution;
  2694 
  2695 * the different sections in a .thy file can now be mixed and repeated
  2696 freely;
  2697 
  2698 * Database of theorems for FOL, HOL and ZF.  New
  2699 commands including qed, qed_goal and bind_thm store theorems in the database.
  2700 
  2701 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2702 a given theory (thms_of), or find out what theory a theorem was proved in
  2703 (theory_of_thm);
  2704 
  2705 * Bugs fixed in the inductive definition and datatype packages;
  2706 
  2707 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2708 and HOL_dup_cs obsolete;
  2709 
  2710 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2711 have been removed;
  2712 
  2713 * Simpler definition of function space in ZF;
  2714 
  2715 * new results about cardinal and ordinal arithmetic in ZF;
  2716 
  2717 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2718 types;
  2719 
  2720 
  2721 $Id$