NEWS
author wenzelm
Thu Apr 29 06:01:20 2004 +0200 (2004-04-29)
changeset 14682 a5072752114c
parent 14655 8a95abf87dd3
child 14698 7e4dec3fd515
permissions -rw-r--r--
HOLCF: discontinued special version of 'constdefs';
     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 -- some existing specifications may have to
    15 be reordered; moreover, the declared name needs to be an identifier.
    16 In the worst case may have to fall back on plain 'consts' + 'defs'.
    17 
    18 * Pure: 'advanced' translation functions (parse_translation etc.) may
    19 depend on the signature of the theory context being presently used for
    20 parsing/printing, see also isar-ref manual.
    21 
    22 
    23 *** HOLCF ***
    24 
    25 * HOLCF: discontinued special version of 'constdefs' (which used to
    26 support continuous functions) in favor of the general Pure one with
    27 full type-inference.
    28 
    29 
    30 
    31 New in Isabelle2004 (April 2004)
    32 --------------------------------
    33 
    34 *** General ***
    35 
    36 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    37   Replaces linorder.ML.
    38 
    39 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
    40   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
    41   (\<a>...\<z>), are now considered normal letters, and can therefore
    42   be used anywhere where an ASCII letter (a...zA...Z) has until
    43   now. COMPATIBILITY: This obviously changes the parsing of some
    44   terms, especially where a symbol has been used as a binder, say
    45   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    46   as an identifier.  Fix it by inserting a space around former
    47   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    48   existing theory and ML files.
    49 
    50 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    51 
    52 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    53   allowed in identifiers. Similar to Greek letters \<^isub> is now considered 
    54   a normal (but invisible) letter. For multiple letter subscripts repeat 
    55   \<^isub> like this: x\<^isub>1\<^isub>2. 
    56 
    57 * Pure: There are now sub-/superscripts that can span more than one
    58   character. Text between \<^bsub> and \<^esub> is set in subscript in
    59   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
    60   superscript. The new control characters are not identifier parts.
    61 
    62 * Pure: Control-symbols of the form \<^raw:...> will literally print the
    63   content of "..." to the latex file instead of \isacntrl... . The "..."
    64   may consist of any printable characters excluding the end bracket >.
    65 
    66 * Pure: Using new Isar command "finalconsts" (or the ML functions
    67   Theory.add_finals or Theory.add_finals_i) it is now possible to
    68   declare constants "final", which prevents their being given a definition
    69   later.  It is useful for constants whose behaviour is fixed axiomatically
    70   rather than definitionally, such as the meta-logic connectives.
    71 
    72 * Pure: 'instance' now handles general arities with general sorts
    73   (i.e. intersections of classes),
    74 
    75 * Presentation: generated HTML now uses a CSS style sheet to make layout
    76   (somewhat) independent of content. It is copied from lib/html/isabelle.css. 
    77   It can be changed to alter the colors/layout of generated pages.
    78 
    79 
    80 *** Isar ***
    81 
    82 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
    83   cut_tac, subgoal_tac and thin_tac:
    84   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    85     locales are no longer forced to write Isar proof scripts.
    86     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    87     emulations.
    88   - INCOMPATIBILITY: names of variables to be instantiated may no
    89     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    90     This is consistent with the instantiation attribute "where".
    91 
    92 * Attributes "where" and "of":
    93   - Now take type variables of instantiated theorem into account when reading
    94     the instantiation string.  This fixes a bug that caused instantiated
    95     theorems to have too special types in some circumstances.
    96   - "where" permits explicit instantiations of type variables.
    97 
    98 * Calculation commands "moreover" and "also" no longer interfere with
    99   current facts ("this"), admitting arbitrary combinations with "then"
   100   and derived forms.
   101 
   102 * Locales:
   103   - Goal statements involving the context element "includes" no longer
   104     generate theorems with internal delta predicates (those ending on
   105     "_axioms") in the premise.
   106     Resolve particular premise with <locale>.intro to obtain old form.
   107   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   108     specification and "includes" elements in goal statement.
   109   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   110     [intro?] and [elim?] (respectively) by default.
   111   - Experimental command for instantiation of locales in proof contexts:
   112         instantiate <label>[<attrs>]: <loc>
   113     Instantiates locale <loc> and adds all its theorems to the current context
   114     taking into account their attributes.  Label and attrs are optional
   115     modifiers, like in theorem declarations.  If present, names of
   116     instantiated theorems are qualified with <label>, and the attributes
   117     <attrs> are applied after any attributes these theorems might have already.
   118       If the locale has assumptions, a chained fact of the form
   119     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   120     are derived.  The command does not support old-style locales declared
   121     with "locale (open)".
   122       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   123 
   124 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   125   (Isar) contexts.
   126 
   127 
   128 *** HOL ***
   129 
   130 * Proof import: new image HOL4 contains the imported library from
   131   the HOL4 system with about 2500 theorems. It is imported by
   132   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   133   can be used like any other Isabelle image.  See
   134   HOL/Import/HOL/README for more information.
   135 
   136 * Simplifier:
   137   - Much improved handling of linear and partial orders.
   138     Reasoners for linear and partial orders are set up for type classes
   139     "linorder" and "order" respectively, and are added to the default simpset
   140     as solvers.  This means that the simplifier can build transitivity chains
   141     to solve goals from the assumptions.
   142   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   143     of blast or auto after simplification become unnecessary because the goal
   144     is solved by simplification already.
   145 
   146 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   147     all proved in axiomatic type classes for semirings, rings and fields.
   148 
   149 * Numerics:
   150   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   151     now formalized using the Ring_and_Field theory mentioned above. 
   152   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   153     than before, because now they are set up once in a generic manner.
   154   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   155     Look for the general versions in Ring_and_Field (and Power if they concern
   156     exponentiation).
   157 
   158 * Type "rat" of the rational numbers is now available in HOL-Complex.
   159 
   160 * Records:
   161   - Record types are now by default printed with their type abbreviation
   162     instead of the list of all field types. This can be configured via
   163     the reference "print_record_type_abbr".
   164   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   165     (not enabled by default).
   166   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   167     EX x. x = sel r to True (not enabled by default).
   168   - Tactic "record_split_simp_tac" to split and simplify records added.
   169  
   170 * 'specification' command added, allowing for definition by
   171   specification.  There is also an 'ax_specification' command that
   172   introduces the new constants axiomatically.
   173 
   174 * arith(_tac) is now able to generate counterexamples for reals as well.
   175 
   176 * HOL-Algebra: new locale "ring" for non-commutative rings.
   177 
   178 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   179   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   180 
   181 * HOL-Matrix: a first theory for matrices in HOL with an application of 
   182   matrix theory to linear programming.
   183 
   184 * Unions and Intersections:
   185   The x-symbol output syntax of UN and INT has been changed
   186   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   187   i.e. the index formulae has become a subscript, like in normal math.
   188   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   189   The subscript version is also accepted as input syntax.
   190 
   191 * Unions and Intersections over Intervals:
   192   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   193   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   194   like in normal math, and corresponding versions for < and for intersection.
   195 
   196 * ML: the legacy theory structures Int and List have been removed. They had
   197   conflicted with ML Basis Library structures having the same names.
   198 
   199 * 'refute' command added to search for (finite) countermodels.  Only works
   200   for a fragment of HOL.  The installation of an external SAT solver is
   201   highly recommended.  See "HOL/Refute.thy" for details.
   202 
   203 * 'quickcheck' command: Allows to find counterexamples by evaluating
   204   formulae under an assignment of free variables to random values.
   205   In contrast to 'refute', it can deal with inductive datatypes,
   206   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   207   for examples.
   208 
   209 
   210 *** HOLCF ***
   211 
   212 * Streams now come with concatenation and are part of the HOLCF image
   213 
   214 
   215 
   216 New in Isabelle2003 (May 2003)
   217 ------------------------------
   218 
   219 *** General ***
   220 
   221 * Provers/simplifier:
   222 
   223   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   224     Assumptions are now subject to complete mutual simplification,
   225     not just from left to right. The simplifier now preserves
   226     the order of assumptions.
   227 
   228     Potential INCOMPATIBILITY:
   229 
   230     -- simp sometimes diverges where the old version did
   231        not, e.g. invoking simp on the goal
   232 
   233         [| P (f x); y = x; f x = f y |] ==> Q
   234 
   235        now gives rise to the infinite reduction sequence
   236 
   237         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   238 
   239        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   240        kind of problem.
   241 
   242     -- Tactics combining classical reasoner and simplification (such as auto)
   243        are also affected by this change, because many of them rely on
   244        simp. They may sometimes diverge as well or yield a different numbers
   245        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   246        in case of problems. Sometimes subsequent calls to the classical
   247        reasoner will fail because a preceeding call to the simplifier too
   248        eagerly simplified the goal, e.g. deleted redundant premises.
   249 
   250   - The simplifier trace now shows the names of the applied rewrite rules
   251 
   252   - You can limit the number of recursive invocations of the simplifier
   253     during conditional rewriting (where the simplifie tries to solve the
   254     conditions before applying the rewrite rule):
   255     ML "simp_depth_limit := n"
   256     where n is an integer. Thus you can force termination where previously
   257     the simplifier would diverge.
   258 
   259   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   260 
   261   - No longer aborts on failed congruence proof.  Instead, the
   262     congruence is ignored.
   263 
   264 * Pure: New generic framework for extracting programs from constructive
   265   proofs. See HOL/Extraction.thy for an example instantiation, as well
   266   as HOL/Extraction for some case studies.
   267 
   268 * Pure: The main goal of the proof state is no longer shown by default, only
   269 the subgoals. This behaviour is controlled by a new flag.
   270    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   271 (ML: Proof.show_main_goal).
   272 
   273 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   274 rules whose conclusion matches subgoal 1:
   275       PG menu: Isabelle/Isar -> Show me -> matching rules
   276 The rules are ordered by how closely they match the subgoal.
   277 In particular, rules that solve a subgoal outright are displayed first
   278 (or rather last, the way they are printed).
   279 (ML: ProofGeneral.print_intros())
   280 
   281 * Pure: New flag trace_unify_fail causes unification to print
   282 diagnostic information (PG: in trace buffer) when it fails. This is
   283 useful for figuring out why single step proofs like rule, erule or
   284 assumption failed.
   285 
   286 * Pure: Locale specifications now produce predicate definitions
   287 according to the body of text (covering assumptions modulo local
   288 definitions); predicate "loc_axioms" covers newly introduced text,
   289 while "loc" is cumulative wrt. all included locale expressions; the
   290 latter view is presented only on export into the global theory
   291 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   292 on the old view without predicates;
   293 
   294 * Pure: predefined locales "var" and "struct" are useful for sharing
   295 parameters (as in CASL, for example); just specify something like
   296 ``var x + var y + struct M'' as import;
   297 
   298 * Pure: improved thms_containing: proper indexing of facts instead of
   299 raw theorems; check validity of results wrt. current name space;
   300 include local facts of proof configuration (also covers active
   301 locales), cover fixed variables in index; may use "_" in term
   302 specification; an optional limit for the number of printed facts may
   303 be given (the default is 40);
   304 
   305 * Pure: disallow duplicate fact bindings within new-style theory files
   306 (batch-mode only);
   307 
   308 * Provers: improved induct method: assumptions introduced by case
   309 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   310 the goal statement); "foo" still refers to all facts collectively;
   311 
   312 * Provers: the function blast.overloaded has been removed: all constants
   313 are regarded as potentially overloaded, which improves robustness in exchange
   314 for slight decrease in efficiency;
   315 
   316 * Provers/linorder: New generic prover for transitivity reasoning over
   317 linear orders.  Note: this prover is not efficient!
   318 
   319 * Isar: preview of problems to finish 'show' now produce an error
   320 rather than just a warning (in interactive mode);
   321 
   322 
   323 *** HOL ***
   324 
   325 * arith(_tac)
   326 
   327  - Produces a counter example if it cannot prove a goal.
   328    Note that the counter example may be spurious if the goal is not a formula
   329    of quantifier-free linear arithmetic.
   330    In ProofGeneral the counter example appears in the trace buffer.
   331 
   332  - Knows about div k and mod k where k is a numeral of type nat or int.
   333 
   334  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   335    linear arithmetic fails. This takes account of quantifiers and divisibility.
   336    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   337 
   338 * simp's arithmetic capabilities have been enhanced a bit: it now
   339 takes ~= in premises into account (by performing a case split);
   340 
   341 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   342 are distributed over a sum of terms;
   343 
   344 * New tactic "trans_tac" and method "trans" instantiate
   345 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   346 "<=", "<" and "="). 
   347 
   348 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   349 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   350 
   351 * 'typedef' command has new option "open" to suppress the set
   352 definition;
   353 
   354 * functions Min and Max on finite sets have been introduced (theory
   355 Finite_Set);
   356 
   357 * attribute [symmetric] now works for relations as well; it turns
   358 (x,y) : R^-1 into (y,x) : R, and vice versa;
   359 
   360 * induct over a !!-quantified statement (say !!x1..xn):
   361   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   362 
   363 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   364 %x. None. Warning: empty_def now refers to the previously hidden definition
   365 of the empty set.
   366 
   367 * Algebra: formalization of classical algebra.  Intended as base for
   368 any algebraic development in Isabelle.  Currently covers group theory
   369 (up to Sylow's theorem) and ring theory (Universal Property of
   370 Univariate Polynomials).  Contributions welcome;
   371 
   372 * GroupTheory: deleted, since its material has been moved to Algebra;
   373 
   374 * Complex: new directory of the complex numbers with numeric constants, 
   375 nonstandard complex numbers, and some complex analysis, standard and 
   376 nonstandard (Jacques Fleuriot);
   377 
   378 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   379 
   380 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   381 Fleuriot);
   382 
   383 * Real/HahnBanach: updated and adapted to locales;
   384 
   385 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   386 Gray and Kramer);
   387 
   388 * UNITY: added the Meier-Sanders theory of progress sets;
   389 
   390 * MicroJava: bytecode verifier and lightweight bytecode verifier
   391 as abstract algorithms, instantiated to the JVM;
   392 
   393 * Bali: Java source language formalization. Type system, operational
   394 semantics, axiomatic semantics. Supported language features:
   395 classes, interfaces, objects,virtual methods, static methods,
   396 static/instance fields, arrays, access modifiers, definite
   397 assignment, exceptions.
   398 
   399 
   400 *** ZF ***
   401 
   402 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   403 universe, etc.);
   404 
   405 * Main ZF: virtually all theories converted to new-style format;
   406 
   407 
   408 *** ML ***
   409 
   410 * Pure: Tactic.prove provides sane interface for internal proofs;
   411 omits the infamous "standard" operation, so this is more appropriate
   412 than prove_goalw_cterm in many situations (e.g. in simprocs);
   413 
   414 * Pure: improved error reporting of simprocs;
   415 
   416 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   417 up simprocs;
   418 
   419 
   420 *** Document preparation ***
   421 
   422 * uses \par instead of \\ for line breaks in theory text. This may
   423 shift some page breaks in large documents. To get the old behaviour
   424 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   425 
   426 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   427 other packages
   428 
   429 * \<euro> now needs package babel/greek instead of marvosym (which
   430 broke \Rightarrow)
   431 
   432 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   433 textcomp package)
   434 
   435 
   436 
   437 New in Isabelle2002 (March 2002)
   438 --------------------------------
   439 
   440 *** Document preparation ***
   441 
   442 * greatly simplified document preparation setup, including more
   443 graceful interpretation of isatool usedir -i/-d/-D options, and more
   444 instructive isatool mkdir; users should basically be able to get
   445 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   446 users may run a separate document processing stage manually like this:
   447 "isatool usedir -D output HOL Test && isatool document Test/output";
   448 
   449 * theory dependency graph may now be incorporated into documents;
   450 isatool usedir -g true will produce session_graph.eps/.pdf for use
   451 with \includegraphics of LaTeX;
   452 
   453 * proper spacing of consecutive markup elements, especially text
   454 blocks after section headings;
   455 
   456 * support bold style (for single symbols only), input syntax is like
   457 this: "\<^bold>\<alpha>" or "\<^bold>A";
   458 
   459 * \<bullet> is now output as bold \cdot by default, which looks much
   460 better in printed text;
   461 
   462 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   463 note that these symbols are currently unavailable in Proof General /
   464 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   465 
   466 * isatool latex no longer depends on changed TEXINPUTS, instead
   467 isatool document copies the Isabelle style files to the target
   468 location;
   469 
   470 
   471 *** Isar ***
   472 
   473 * Pure/Provers: improved proof by cases and induction;
   474   - 'case' command admits impromptu naming of parameters (such as
   475     "case (Suc n)");
   476   - 'induct' method divinates rule instantiation from the inductive
   477     claim; no longer requires excessive ?P bindings for proper
   478     instantiation of cases;
   479   - 'induct' method properly enumerates all possibilities of set/type
   480     rules; as a consequence facts may be also passed through *type*
   481     rules without further ado;
   482   - 'induct' method now derives symbolic cases from the *rulified*
   483     rule (before it used to rulify cases stemming from the internal
   484     atomized version); this means that the context of a non-atomic
   485     statement becomes is included in the hypothesis, avoiding the
   486     slightly cumbersome show "PROP ?case" form;
   487   - 'induct' may now use elim-style induction rules without chaining
   488     facts, using ``missing'' premises from the goal state; this allows
   489     rules stemming from inductive sets to be applied in unstructured
   490     scripts, while still benefitting from proper handling of non-atomic
   491     statements; NB: major inductive premises need to be put first, all
   492     the rest of the goal is passed through the induction;
   493   - 'induct' proper support for mutual induction involving non-atomic
   494     rule statements (uses the new concept of simultaneous goals, see
   495     below);
   496   - append all possible rule selections, but only use the first
   497     success (no backtracking);
   498   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   499   - undeclared rule case names default to numbers 1, 2, 3, ...;
   500   - added 'print_induct_rules' (covered by help item in recent Proof
   501     General versions);
   502   - moved induct/cases attributes to Pure, methods to Provers;
   503   - generic method setup instantiated for FOL and HOL;
   504 
   505 * Pure: support multiple simultaneous goal statements, for example
   506 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   507 meta-level mechanism, this acts as if several individual goals had
   508 been stated separately; in particular common proof methods need to be
   509 repeated in order to cover all claims; note that a single elimination
   510 step is *not* sufficient to establish the two conjunctions, so this
   511 fails:
   512 
   513   assume "A & B" then have A and B ..   (*".." fails*)
   514 
   515 better use "obtain" in situations as above; alternative refer to
   516 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   517 
   518 * Pure: proper integration with ``locales''; unlike the original
   519 version by Florian Kammüller, Isar locales package high-level proof
   520 contexts rather than raw logical ones (e.g. we admit to include
   521 attributes everywhere); operations on locales include merge and
   522 rename; support for implicit arguments (``structures''); simultaneous
   523 type-inference over imports and text; see also HOL/ex/Locales.thy for
   524 some examples;
   525 
   526 * Pure: the following commands have been ``localized'', supporting a
   527 target locale specification "(in name)": 'lemma', 'theorem',
   528 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   529 stored both within the locale and at the theory level (exported and
   530 qualified by the locale name);
   531 
   532 * Pure: theory goals may now be specified in ``long'' form, with
   533 ad-hoc contexts consisting of arbitrary locale elements. for example
   534 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   535 definitions may be given, too); the result is a meta-level rule with
   536 the context elements being discharged in the obvious way;
   537 
   538 * Pure: new proof command 'using' allows to augment currently used
   539 facts after a goal statement ('using' is syntactically analogous to
   540 'apply', but acts on the goal's facts only); this allows chained facts
   541 to be separated into parts given before and after a claim, as in
   542 ``from a and b have C using d and e <proof>'';
   543 
   544 * Pure: renamed "antecedent" case to "rule_context";
   545 
   546 * Pure: new 'judgment' command records explicit information about the
   547 object-logic embedding (used by several tools internally); no longer
   548 use hard-wired "Trueprop";
   549 
   550 * Pure: added 'corollary' command;
   551 
   552 * Pure: fixed 'token_translation' command;
   553 
   554 * Pure: removed obsolete 'exported' attribute;
   555 
   556 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   557 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   558 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   559 
   560 * Pure: method 'atomize' presents local goal premises as object-level
   561 statements (atomic meta-level propositions); setup controlled via
   562 rewrite rules declarations of 'atomize' attribute; example
   563 application: 'induct' method with proper rule statements in improper
   564 proof *scripts*;
   565 
   566 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   567 now consider the syntactic context of assumptions, giving a better
   568 chance to get type-inference of the arguments right (this is
   569 especially important for locales);
   570 
   571 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   572 mode;
   573 
   574 * Pure/obtain: the formal conclusion "thesis", being marked as
   575 ``internal'', may no longer be reference directly in the text;
   576 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   577 situations;
   578 
   579 * Pure: generic 'sym' attribute which declares a rule both as pure
   580 'elim?' and for the 'symmetric' operation;
   581 
   582 * Pure: marginal comments ``--'' may now occur just anywhere in the
   583 text; the fixed correlation with particular command syntax has been
   584 discontinued;
   585 
   586 * Pure: new method 'rules' is particularly well-suited for proof
   587 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   588 but often produces more compact proof terms with less detours;
   589 
   590 * Pure/Provers/classical: simplified integration with pure rule
   591 attributes and methods; the classical "intro?/elim?/dest?"
   592 declarations coincide with the pure ones; the "rule" method no longer
   593 includes classically swapped intros; "intro" and "elim" methods no
   594 longer pick rules from the context; also got rid of ML declarations
   595 AddXIs/AddXEs/AddXDs; all of this has some potential for
   596 INCOMPATIBILITY;
   597 
   598 * Provers/classical: attribute 'swapped' produces classical inversions
   599 of introduction rules;
   600 
   601 * Provers/simplifier: 'simplified' attribute may refer to explicit
   602 rules instead of full simplifier context; 'iff' attribute handles
   603 conditional rules;
   604 
   605 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   606 
   607 * HOL: 'recdef' now fails on unfinished automated proofs, use
   608 "(permissive)" option to recover old behavior;
   609 
   610 * HOL: 'inductive' no longer features separate (collective) attributes
   611 for 'intros' (was found too confusing);
   612 
   613 * HOL: properly declared induction rules less_induct and
   614 wf_induct_rule;
   615 
   616 
   617 *** HOL ***
   618 
   619 * HOL: moved over to sane numeral syntax; the new policy is as
   620 follows:
   621 
   622   - 0 and 1 are polymorphic constants, which are defined on any
   623   numeric type (nat, int, real etc.);
   624 
   625   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   626   binary representation internally;
   627 
   628   - type nat has special constructor Suc, and generally prefers Suc 0
   629   over 1::nat and Suc (Suc 0) over 2::nat;
   630 
   631 This change may cause significant problems of INCOMPATIBILITY; here
   632 are some hints on converting existing sources:
   633 
   634   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   635   entities, so expressions involving "-" (unary or binary minus) need
   636   to be spaced properly;
   637 
   638   - existing occurrences of "1" may need to be constraint "1::nat" or
   639   even replaced by Suc 0; similar for old "2";
   640 
   641   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   642 
   643   - remove all special provisions on numerals in proofs;
   644 
   645 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   646 representation (depends on bin_arith_simps in the default context);
   647 
   648 * HOL: symbolic syntax for x^2 (numeral 2);
   649 
   650 * HOL: the class of all HOL types is now called "type" rather than
   651 "term"; INCOMPATIBILITY, need to adapt references to this type class
   652 in axclass/classes, instance/arities, and (usually rare) occurrences
   653 in typings (of consts etc.); internally the class is called
   654 "HOL.type", ML programs should refer to HOLogic.typeS;
   655 
   656 * HOL/record package improvements:
   657   - new derived operations "fields" to build a partial record section,
   658     "extend" to promote a fixed record to a record scheme, and
   659     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   660     declared as simp by default;
   661   - shared operations ("more", "fields", etc.) now need to be always
   662     qualified) --- potential INCOMPATIBILITY;
   663   - removed "make_scheme" operations (use "make" with "extend") --
   664     INCOMPATIBILITY;
   665   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   666   - provides cases/induct rules for use with corresponding Isar
   667     methods (for concrete records, record schemes, concrete more
   668     parts, and schematic more parts -- in that order);
   669   - internal definitions directly based on a light-weight abstract
   670     theory of product types over typedef rather than datatype;
   671 
   672 * HOL: generic code generator for generating executable ML code from
   673 specifications; specific support for HOL constructs such as inductive
   674 datatypes and sets, as well as recursive functions; can be invoked
   675 via 'generate_code' theory section;
   676 
   677 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   678 
   679 * HOL: consolidated and renamed several theories.  In particular:
   680 	Ord.thy has been absorbed into HOL.thy
   681 	String.thy has been absorbed into List.thy
   682  
   683 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   684 (beware of argument permutation!);
   685 
   686 * HOL: linorder_less_split superseded by linorder_cases;
   687 
   688 * HOL/List: "nodups" renamed to "distinct";
   689 
   690 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   691 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   692   - Ex_def has changed, now need to use some_eq_ex
   693 
   694 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   695 in this (rare) case use:
   696 
   697   delSWrapper "split_all_tac"
   698   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   699 
   700 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   701 MAY FAIL;
   702 
   703 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   704 Isabelle's type classes, ^ on functions and relations has too general
   705 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   706 necessary to attach explicit type constraints;
   707 
   708 * HOL/Relation: the prefix name of the infix "O" has been changed from
   709 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   710 renamed accordingly (eg "compI" -> "rel_compI").
   711 
   712 * HOL: syntax translations now work properly with numerals and records
   713 expressions;
   714 
   715 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   716 of "lam" -- INCOMPATIBILITY;
   717 
   718 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   719 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   720 renamed "Product_Type.unit";
   721 
   722 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   723 
   724 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   725 the "cases" method);
   726 
   727 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   728 Florian Kammüller);
   729 
   730 * HOL/IMP: updated and converted to new-style theory format; several
   731 parts turned into readable document, with proper Isar proof texts and
   732 some explanations (by Gerwin Klein);
   733 
   734 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   735 
   736 * HOL-Hyperreal is now a logic image;
   737 
   738 
   739 *** HOLCF ***
   740 
   741 * Isar: consts/constdefs supports mixfix syntax for continuous
   742 operations;
   743 
   744 * Isar: domain package adapted to new-style theory format, e.g. see
   745 HOLCF/ex/Dnat.thy;
   746 
   747 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   748 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   749 lift.induct_tac, always use UU instead of Undef;
   750 
   751 * HOLCF/IMP: updated and converted to new-style theory;
   752 
   753 
   754 *** ZF ***
   755 
   756 * Isar: proper integration of logic-specific tools and packages,
   757 including theory commands '(co)inductive', '(co)datatype',
   758 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   759 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   760 
   761 * theory Main no longer includes AC; for the Axiom of Choice, base
   762 your theory on Main_ZFC;
   763 
   764 * the integer library now covers quotients and remainders, with many
   765 laws relating division to addition, multiplication, etc.;
   766 
   767 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   768 typeless version of the formalism;
   769 
   770 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   771 format;
   772 
   773 * ZF/Induct: new directory for examples of inductive definitions,
   774 including theory Multiset for multiset orderings; converted to
   775 new-style theory format;
   776 
   777 * ZF: many new theorems about lists, ordinals, etc.;
   778 
   779 
   780 *** General ***
   781 
   782 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   783 variable proof controls level of detail: 0 = no proofs (only oracle
   784 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   785 also ref manual for further ML interfaces;
   786 
   787 * Pure/axclass: removed obsolete ML interface
   788 goal_subclass/goal_arity;
   789 
   790 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   791 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   792 separate tokens, so expressions involving minus need to be spaced
   793 properly;
   794 
   795 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   796 rather than "infixl" or "infixr";
   797 
   798 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   799 sort constraint specifications in type inference; e.g. "x::_::foo"
   800 ensures that the type of "x" is of sort "foo" (but not necessarily a
   801 type variable);
   802 
   803 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   804 control output of nested => (types); the default behavior is
   805 "type_brackets";
   806 
   807 * Pure/syntax: builtin parse translation for "_constify" turns valued
   808 tokens into AST constants;
   809 
   810 * Pure/syntax: prefer later declarations of translations and print
   811 translation functions; potential INCOMPATIBILITY: need to reverse
   812 multiple declarations for same syntax element constant;
   813 
   814 * Pure/show_hyps reset by default (in accordance to existing Isar
   815 practice);
   816 
   817 * Provers/classical: renamed addaltern to addafter, addSaltern to
   818 addSafter;
   819 
   820 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   821 as well;
   822 
   823 * system: tested support for MacOS X; should be able to get Isabelle +
   824 Proof General to work in a plain Terminal after installing Poly/ML
   825 (e.g. from the Isabelle distribution area) and GNU bash alone
   826 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   827 support requires further installations, e.g. from
   828 http://fink.sourceforge.net/);
   829 
   830 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   831 
   832 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   833 of 40 MB), cf. ML_OPTIONS;
   834 
   835 * system: Proof General keywords specification is now part of the
   836 Isabelle distribution (see etc/isar-keywords.el);
   837 
   838 * system: support for persistent Proof General sessions (refrain from
   839 outdating all loaded theories on startup); user may create writable
   840 logic images like this: ``isabelle -q HOL Test'';
   841 
   842 * system: smart selection of Isabelle process versus Isabelle
   843 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   844 run both "isabelle" and "Isabelle" even if file names are badly
   845 damaged (executable inspects the case of the first letter of its own
   846 name); added separate "isabelle-process" and "isabelle-interface";
   847 
   848 * system: refrain from any attempt at filtering input streams; no
   849 longer support ``8bit'' encoding of old isabelle font, instead proper
   850 iso-latin characters may now be used; the related isatools
   851 "symbolinput" and "nonascii" have disappeared as well;
   852 
   853 * system: removed old "xterm" interface (the print modes "xterm" and
   854 "xterm_color" are still available for direct use in a suitable
   855 terminal);
   856 
   857 
   858 
   859 New in Isabelle99-2 (February 2001)
   860 -----------------------------------
   861 
   862 *** Overview of INCOMPATIBILITIES ***
   863 
   864 * HOL: please note that theories in the Library and elsewhere often use the
   865 new-style (Isar) format; to refer to their theorems in an ML script you must
   866 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   867 
   868 * HOL: inductive package no longer splits induction rule aggressively,
   869 but only as far as specified by the introductions given; the old
   870 format may be recovered via ML function complete_split_rule or attribute
   871 'split_rule (complete)';
   872 
   873 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   874 gfp_Tarski to gfp_unfold;
   875 
   876 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   877 
   878 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   879 relation); infix "^^" has been renamed "``"; infix "``" has been
   880 renamed "`"; "univalent" has been renamed "single_valued";
   881 
   882 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   883 operation;
   884 
   885 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   886 
   887 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   888 
   889 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   890 consequence, it is no longer monotonic wrt. the local goal context
   891 (which is now passed through the inductive cases);
   892 
   893 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   894 \<gg> to \<ggreater>;
   895 
   896 
   897 *** Document preparation ***
   898 
   899 * \isabellestyle{NAME} selects version of Isabelle output (currently
   900 available: are "it" for near math-mode best-style output, "sl" for
   901 slanted text style, and "tt" for plain type-writer; if no
   902 \isabellestyle command is given, output is according to slanted
   903 type-writer);
   904 
   905 * support sub/super scripts (for single symbols only), input syntax is
   906 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   907 
   908 * some more standard symbols; see Appendix A of the system manual for
   909 the complete list of symbols defined in isabellesym.sty;
   910 
   911 * improved isabelle style files; more abstract symbol implementation
   912 (should now use \isamath{...} and \isatext{...} in custom symbol
   913 definitions);
   914 
   915 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   916 state; Note that presentation of goal states does not conform to
   917 actual human-readable proof documents.  Please do not include goal
   918 states into document output unless you really know what you are doing!
   919 
   920 * proper indentation of antiquoted output with proportional LaTeX
   921 fonts;
   922 
   923 * no_document ML operator temporarily disables LaTeX document
   924 generation;
   925 
   926 * isatool unsymbolize tunes sources for plain ASCII communication;
   927 
   928 
   929 *** Isar ***
   930 
   931 * Pure: Isar now suffers initial goal statements to contain unbound
   932 schematic variables (this does not conform to actual readable proof
   933 documents, due to unpredictable outcome and non-compositional proof
   934 checking); users who know what they are doing may use schematic goals
   935 for Prolog-style synthesis of proven results;
   936 
   937 * Pure: assumption method (an implicit finishing) now handles actual
   938 rules as well;
   939 
   940 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   941 initial goal, declare "that" only as Pure intro (only for single
   942 steps); the "that" rule assumption may now be involved in implicit
   943 finishing, thus ".." becomes a feasible for trivial obtains;
   944 
   945 * Pure: default proof step now includes 'intro_classes'; thus trivial
   946 instance proofs may be performed by "..";
   947 
   948 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   949 statements as well;
   950 
   951 * Pure: more robust selection of calculational rules;
   952 
   953 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   954 rule (as well as the assumption rule);
   955 
   956 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   957 lemmas, using the graph browser tool;
   958 
   959 * Pure: predict failure of "show" in interactive mode;
   960 
   961 * Pure: 'thms_containing' now takes actual terms as arguments;
   962 
   963 * HOL: improved method 'induct' --- now handles non-atomic goals
   964 (potential INCOMPATIBILITY); tuned error handling;
   965 
   966 * HOL: cases and induct rules now provide explicit hints about the
   967 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   968 any remaining facts are inserted into the goal verbatim;
   969 
   970 * HOL: local contexts (aka cases) may now contain term bindings as
   971 well; the 'cases' and 'induct' methods new provide a ?case binding for
   972 the result to be shown in each case;
   973 
   974 * HOL: added 'recdef_tc' command;
   975 
   976 * isatool convert assists in eliminating legacy ML scripts;
   977 
   978 
   979 *** HOL ***
   980 
   981 * HOL/Library: a collection of generic theories to be used together
   982 with main HOL; the theory loader path already includes this directory
   983 by default; the following existing theories have been moved here:
   984 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   985 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   986 
   987 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   988 modelling and verification task performed in Isabelle/HOL +
   989 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   990 
   991 * HOL/Algebra: special summation operator SUM no longer exists, it has
   992 been replaced by setsum; infix 'assoc' now has priority 50 (like
   993 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   994 'domain', this makes the theory consistent with mathematical
   995 literature;
   996 
   997 * HOL basics: added overloaded operations "inverse" and "divide"
   998 (infix "/"), syntax for generic "abs" operation, generic summation
   999 operator \<Sum>;
  1000 
  1001 * HOL/typedef: simplified package, provide more useful rules (see also
  1002 HOL/subset.thy);
  1003 
  1004 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1005 now expressed as a proper nested rule (old-style tactic scripts may
  1006 require atomize_strip_tac to cope with non-atomic premises);
  1007 
  1008 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1009 to "split_conv" (old name still available for compatibility);
  1010 
  1011 * HOL: improved concrete syntax for strings (e.g. allows translation
  1012 rules with string literals);
  1013 
  1014 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1015  and Fleuriot's mechanization of analysis, including the transcendental
  1016  functions for the reals;
  1017 
  1018 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1019 
  1020 
  1021 *** CTT ***
  1022 
  1023 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1024 "lam" is displayed as TWO lambda-symbols
  1025 
  1026 * CTT: theory Main now available, containing everything (that is, Bool
  1027 and Arith);
  1028 
  1029 
  1030 *** General ***
  1031 
  1032 * Pure: the Simplifier has been implemented properly as a derived rule
  1033 outside of the actual kernel (at last!); the overall performance
  1034 penalty in practical applications is about 50%, while reliability of
  1035 the Isabelle inference kernel has been greatly improved;
  1036 
  1037 * print modes "brackets" and "no_brackets" control output of nested =>
  1038 (types) and ==> (props); the default behaviour is "brackets";
  1039 
  1040 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1041 as assumptions as well;
  1042 
  1043 * system: support Poly/ML 4.0;
  1044 
  1045 * system: isatool install handles KDE version 1 or 2;
  1046 
  1047 
  1048 
  1049 New in Isabelle99-1 (October 2000)
  1050 ----------------------------------
  1051 
  1052 *** Overview of INCOMPATIBILITIES ***
  1053 
  1054 * HOL: simplification of natural numbers is much changed; to partly
  1055 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1056 issue the following ML commands:
  1057 
  1058   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1059   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1060 
  1061 * HOL: simplification no longer dives into case-expressions; this is
  1062 controlled by "t.weak_case_cong" for each datatype t;
  1063 
  1064 * HOL: nat_less_induct renamed to less_induct;
  1065 
  1066 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1067 fixsome to patch .thy and .ML sources automatically;
  1068 
  1069   select_equality  -> some_equality
  1070   select_eq_Ex     -> some_eq_ex
  1071   selectI2EX       -> someI2_ex
  1072   selectI2         -> someI2
  1073   selectI          -> someI
  1074   select1_equality -> some1_equality
  1075   Eps_sym_eq       -> some_sym_eq_trivial
  1076   Eps_eq           -> some_eq_trivial
  1077 
  1078 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1079 
  1080 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1081 instead);
  1082 
  1083 * HOL: the recursion equations generated by 'recdef' are now called
  1084 f.simps instead of f.rules;
  1085 
  1086 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1087 
  1088 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1089 sometimes be needed;
  1090 
  1091 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1092 
  1093 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1094 
  1095 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1096 product is now "<*>" instead of "Times"; the lexicographic product is
  1097 now "<*lex*>" instead of "**";
  1098 
  1099 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1100 of main HOL, but was unused); better use HOL's datatype package;
  1101 
  1102 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1103 the old syntax may be recovered as follows:
  1104 
  1105   syntax (symbols)
  1106     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1107       (infixl "\\<oplus>" 100)
  1108 
  1109 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1110 
  1111 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1112 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1113 internally;
  1114 
  1115 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1116 changed from A/r to A//r;
  1117 
  1118 * ZF: new treatment of arithmetic (nat & int) may break some old
  1119 proofs;
  1120 
  1121 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1122 rulify -> rule_format, elimify -> elim_format, ...);
  1123 
  1124 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1125 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1126 should have to change intro!! to intro? only); replaced "delrule" by
  1127 "rule del";
  1128 
  1129 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1130 
  1131 * Provers: strengthened force_tac by using new first_best_tac;
  1132 
  1133 * LaTeX document preparation: several changes of isabelle.sty (see
  1134 lib/texinputs);
  1135 
  1136 
  1137 *** Document preparation ***
  1138 
  1139 * formal comments (text blocks etc.) in new-style theories may now
  1140 contain antiquotations of thm/prop/term/typ/text to be presented
  1141 according to latex print mode; concrete syntax is like this:
  1142 @{term[show_types] "f(x) = a + x"};
  1143 
  1144 * isatool mkdir provides easy setup of Isabelle session directories,
  1145 including proper document sources;
  1146 
  1147 * generated LaTeX sources are now deleted after successful run
  1148 (isatool document -c); may retain a copy somewhere else via -D option
  1149 of isatool usedir;
  1150 
  1151 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1152 style files, achieving self-contained LaTeX sources and simplifying
  1153 LaTeX debugging;
  1154 
  1155 * old-style theories now produce (crude) LaTeX output as well;
  1156 
  1157 * browser info session directories are now self-contained (may be put
  1158 on WWW server seperately); improved graphs of nested sessions; removed
  1159 graph for 'all sessions';
  1160 
  1161 * several improvements in isabelle style files; \isabellestyle{it}
  1162 produces fake math mode output; \isamarkupheader is now \section by
  1163 default; see lib/texinputs/isabelle.sty etc.;
  1164 
  1165 
  1166 *** Isar ***
  1167 
  1168 * Isar/Pure: local results and corresponding term bindings are now
  1169 subject to Hindley-Milner polymorphism (similar to ML); this
  1170 accommodates incremental type-inference very nicely;
  1171 
  1172 * Isar/Pure: new derived language element 'obtain' supports
  1173 generalized existence reasoning;
  1174 
  1175 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1176 support accumulation of results, without applying any rules yet;
  1177 useful to collect intermediate results without explicit name
  1178 references, and for use with transitivity rules with more than 2
  1179 premises;
  1180 
  1181 * Isar/Pure: scalable support for case-analysis type proofs: new
  1182 'case' language element refers to local contexts symbolically, as
  1183 produced by certain proof methods; internally, case names are attached
  1184 to theorems as "tags";
  1185 
  1186 * Isar/Pure: theory command 'hide' removes declarations from
  1187 class/type/const name spaces;
  1188 
  1189 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1190 indicate potential overloading;
  1191 
  1192 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1193 
  1194 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1195 "{a,b,c}" instead of {a,b,c};
  1196 
  1197 * Isar/Pure now provides its own version of intro/elim/dest
  1198 attributes; useful for building new logics, but beware of confusion
  1199 with the version in Provers/classical;
  1200 
  1201 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1202 case name 'antecedent';
  1203 
  1204 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1205 to the current context is now done automatically);
  1206 
  1207 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1208 for definining proof methods in ML;
  1209 
  1210 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1211 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1212 most cases, one should have to change intro!! to intro? only);
  1213 replaced "delrule" by "rule del";
  1214 
  1215 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1216 'symmetric' attribute (the latter supercedes [RS sym]);
  1217 
  1218 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1219 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1220 well (including splits);
  1221 
  1222 * Isar/Provers: Simplifier and Classical methods now support all kind
  1223 of modifiers used in the past, including 'cong', 'iff', etc.
  1224 
  1225 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1226 of Simplifier and Classical reasoner);
  1227 
  1228 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1229 now support named cases; major packages (inductive, datatype, primrec,
  1230 recdef) support case names and properly name parameters;
  1231 
  1232 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1233 monotonicity conditions are extracted to be proven at end of
  1234 calculations;
  1235 
  1236 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1237 method anyway;
  1238 
  1239 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1240 split_if split_if_asm; datatype package provides theorems foo.splits =
  1241 foo.split foo.split_asm for each datatype;
  1242 
  1243 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1244 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1245 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1246 use "(cases (simplified))" method in proper proof texts);
  1247 
  1248 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1249 
  1250 * Isar: names of theorems etc. may be natural numbers as well;
  1251 
  1252 * Isar: 'pr' command: optional arguments for goals_limit and
  1253 ProofContext.prems_limit; no longer prints theory contexts, but only
  1254 proof states;
  1255 
  1256 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1257 additional print modes to be specified; e.g. "pr(latex)" will print
  1258 proof state according to the Isabelle LaTeX style;
  1259 
  1260 * Isar: improved support for emulating tactic scripts, including proof
  1261 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1262 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1263 (for HOL datatypes);
  1264 
  1265 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1266 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1267 'proof method scripts' have to be in depth-first order;
  1268 
  1269 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1270 
  1271 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1272 should instead use individual commands for printing items
  1273 (print_commands, print_methods etc.);
  1274 
  1275 * Isar: added 'nothing' --- the empty list of theorems;
  1276 
  1277 
  1278 *** HOL ***
  1279 
  1280 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1281 corresponding virtual machine and a specification of its bytecode
  1282 verifier and a lightweight bytecode verifier, including proofs of
  1283 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1284 Cornelia Pusch (see also the homepage of project Bali at
  1285 http://isabelle.in.tum.de/Bali/);
  1286 
  1287 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1288 Clemens Ballarin;
  1289 
  1290 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1291 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1292 Rasmussen;
  1293 
  1294 * HOL/Lattice: fundamental concepts of lattice theory and order
  1295 structures, including duals, properties of bounds versus algebraic
  1296 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1297 Theorem for complete lattices etc.; may also serve as a demonstration
  1298 for abstract algebraic reasoning using axiomatic type classes, and
  1299 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1300 
  1301 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1302 von Oheimb;
  1303 
  1304 * HOL/IMPP: extension of IMP with local variables and mutually
  1305 recursive procedures, by David von Oheimb;
  1306 
  1307 * HOL/Lambda: converted into new-style theory and document;
  1308 
  1309 * HOL/ex/Multiquote: example of multiple nested quotations and
  1310 anti-quotations -- basically a generalized version of de-Bruijn
  1311 representation; very useful in avoiding lifting of operations;
  1312 
  1313 * HOL/record: added general record equality rule to simpset; fixed
  1314 select-update simplification procedure to handle extended records as
  1315 well; admit "r" as field name;
  1316 
  1317 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1318 other numeric types and also as the identity of groups, rings, etc.;
  1319 
  1320 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1321 Types nat and int belong to this axclass;
  1322 
  1323 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1324    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1325    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1326   two terms #m*u and #n*u are replaced by #(m+n)*u
  1327     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1328   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1329     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1330 
  1331 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1332 powerful prover for predicate logic but knows nothing of clasets; see
  1333 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1334 
  1335 * HOL: new version of "case_tac" subsumes both boolean case split and
  1336 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1337 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1338 
  1339 * HOL: simplification no longer dives into case-expressions: only the
  1340 selector expression is simplified, but not the remaining arms; to
  1341 enable full simplification of case-expressions for datatype t, you may
  1342 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1343 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1344 
  1345 * HOL/recdef: the recursion equations generated by 'recdef' for
  1346 function 'f' are now called f.simps instead of f.rules; if all
  1347 termination conditions are proved automatically, these simplification
  1348 rules are added to the simpset, as in primrec; rules may be named
  1349 individually as well, resulting in a separate list of theorems for
  1350 each equation;
  1351 
  1352 * HOL/While is a new theory that provides a while-combinator. It
  1353 permits the definition of tail-recursive functions without the
  1354 provision of a termination measure. The latter is necessary once the
  1355 invariant proof rule for while is applied.
  1356 
  1357 * HOL: new (overloaded) notation for the set of elements below/above
  1358 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1359 
  1360 * HOL: theorems impI, allI, ballI bound as "strip";
  1361 
  1362 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1363 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1364 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1365 
  1366 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1367 
  1368 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1369 main HOL, but was unused);
  1370 
  1371 * HOL: fewer consts declared as global (e.g. have to refer to
  1372 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1373 
  1374 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1375 in case of overlap with user translations (e.g. judgements over
  1376 tuples); (note that the underlying logical represenation is still
  1377 bogus);
  1378 
  1379 
  1380 *** ZF ***
  1381 
  1382 * ZF: simplification automatically cancels common terms in arithmetic
  1383 expressions over nat and int;
  1384 
  1385 * ZF: new treatment of nat to minimize type-checking: all operators
  1386 coerce their operands to a natural number using the function natify,
  1387 making the algebraic laws unconditional;
  1388 
  1389 * ZF: as above, for int: operators coerce their operands to an integer
  1390 using the function intify;
  1391 
  1392 * ZF: the integer library now contains many of the usual laws for the
  1393 orderings, including $<=, and monotonicity laws for $+ and $*;
  1394 
  1395 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1396 simplification;
  1397 
  1398 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1399 to the simplifier and classical reasoner simultaneously;
  1400 
  1401 
  1402 *** General ***
  1403 
  1404 * Provers: blast_tac now handles actual object-logic rules as
  1405 assumptions; note that auto_tac uses blast_tac internally as well;
  1406 
  1407 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1408 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1409 
  1410 * Provers: delrules now handles destruct rules as well (no longer need
  1411 explicit make_elim);
  1412 
  1413 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1414   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1415 use instead the strong form,
  1416   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1417 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1418 from destruct-rules;
  1419 
  1420 * Provers: Simplifier.easy_setup provides a fast path to basic
  1421 Simplifier setup for new object-logics;
  1422 
  1423 * Pure: AST translation rules no longer require constant head on LHS;
  1424 
  1425 * Pure: improved name spaces: ambiguous output is qualified; support
  1426 for hiding of names;
  1427 
  1428 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1429 XSYMBOL_HOME; no longer need to do manual configuration in most
  1430 situations;
  1431 
  1432 * system: compression of ML heaps images may now be controlled via -c
  1433 option of isabelle and isatool usedir (currently only observed by
  1434 Poly/ML);
  1435 
  1436 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1437 useful for remote X11);
  1438 
  1439 * system: provide TAGS file for Isabelle sources;
  1440 
  1441 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1442 order;
  1443 
  1444 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1445 timing flag supersedes proof_timing and Toplevel.trace;
  1446 
  1447 * ML: new combinators |>> and |>>> for incremental transformations
  1448 with secondary results (e.g. certain theory extensions):
  1449 
  1450 * ML: PureThy.add_defs gets additional argument to indicate potential
  1451 overloading (usually false);
  1452 
  1453 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1454 results;
  1455 
  1456 
  1457 
  1458 New in Isabelle99 (October 1999)
  1459 --------------------------------
  1460 
  1461 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1462 
  1463 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1464 are no longer simplified.  (This allows the simplifier to unfold recursive
  1465 functional programs.)  To restore the old behaviour, declare
  1466 
  1467     Delcongs [if_weak_cong];
  1468 
  1469 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1470 complement;
  1471 
  1472 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1473 
  1474 * HOL/datatype: mutual_induct_tac no longer exists --
  1475   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1476 
  1477 * HOL/typedef: fixed type inference for representing set; type
  1478 arguments now have to occur explicitly on the rhs as type constraints;
  1479 
  1480 * ZF: The con_defs part of an inductive definition may no longer refer
  1481 to constants declared in the same theory;
  1482 
  1483 * HOL, ZF: the function mk_cases, generated by the inductive
  1484 definition package, has lost an argument.  To simplify its result, it
  1485 uses the default simpset instead of a supplied list of theorems.
  1486 
  1487 * HOL/List: the constructors of type list are now Nil and Cons;
  1488 
  1489 * Simplifier: the type of the infix ML functions
  1490         setSSolver addSSolver setSolver addSolver
  1491 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1492 for packaging solvers. A solver is created via
  1493         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1494 where the string argument is only a comment.
  1495 
  1496 
  1497 *** Proof tools ***
  1498 
  1499 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1500 decision procedure for linear arithmetic. Currently it is used for
  1501 types `nat', `int', and `real' in HOL (see below); it can, should and
  1502 will be instantiated for other types and logics as well.
  1503 
  1504 * The simplifier now accepts rewrite rules with flexible heads, eg
  1505      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1506   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1507   matching.
  1508 
  1509 
  1510 *** General ***
  1511 
  1512 * New Isabelle/Isar subsystem provides an alternative to traditional
  1513 tactical theorem proving; together with the ProofGeneral/isar user
  1514 interface it offers an interactive environment for developing human
  1515 readable proof documents (Isar == Intelligible semi-automated
  1516 reasoning); for further information see isatool doc isar-ref,
  1517 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1518 
  1519 * improved and simplified presentation of theories: better HTML markup
  1520 (including colors), graph views in several sizes; isatool usedir now
  1521 provides a proper interface for user theories (via -P option); actual
  1522 document preparation based on (PDF)LaTeX is available as well (for
  1523 new-style theories only); see isatool doc system for more information;
  1524 
  1525 * native support for Proof General, both for classic Isabelle and
  1526 Isabelle/Isar;
  1527 
  1528 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1529 using the graph browser tool;
  1530 
  1531 * Isabelle manuals now also available as PDF;
  1532 
  1533 * theory loader rewritten from scratch (may not be fully
  1534 bug-compatible); old loadpath variable has been replaced by show_path,
  1535 add_path, del_path, reset_path functions; new operations such as
  1536 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1537 isatool doc ref);
  1538 
  1539 * improved isatool install: option -k creates KDE application icon,
  1540 option -p DIR installs standalone binaries;
  1541 
  1542 * added ML_PLATFORM setting (useful for cross-platform installations);
  1543 more robust handling of platform specific ML images for SML/NJ;
  1544 
  1545 * the settings environment is now statically scoped, i.e. it is never
  1546 created again in sub-processes invoked from isabelle, isatool, or
  1547 Isabelle;
  1548 
  1549 * path element specification '~~' refers to '$ISABELLE_HOME';
  1550 
  1551 * in locales, the "assumes" and "defines" parts may be omitted if
  1552 empty;
  1553 
  1554 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1555 long arrows);
  1556 
  1557 * new print_mode "HTML";
  1558 
  1559 * new flag show_tags controls display of tags of theorems (which are
  1560 basically just comments that may be attached by some tools);
  1561 
  1562 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1563 mode and goal output format:
  1564 
  1565 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1566 244c244
  1567 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1568 ---
  1569 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1570 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1571 181c181
  1572 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1573 ---
  1574 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1575 
  1576 * function bind_thms stores lists of theorems (cf. bind_thm);
  1577 
  1578 * new shorthand tactics ftac, eatac, datac, fatac;
  1579 
  1580 * qed (and friends) now accept "" as result name; in that case the
  1581 theorem is not stored, but proper checks and presentation of the
  1582 result still apply;
  1583 
  1584 * theorem database now also indexes constants "Trueprop", "all",
  1585 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1586 
  1587 
  1588 *** HOL ***
  1589 
  1590 ** HOL arithmetic **
  1591 
  1592 * There are now decision procedures for linear arithmetic over nat and
  1593 int:
  1594 
  1595 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1596 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1597 are treated as atomic; subformulae not involving type `nat' or `int'
  1598 are ignored; quantified subformulae are ignored unless they are
  1599 positive universal or negative existential. The tactic has to be
  1600 invoked by hand and can be a little bit slow. In particular, the
  1601 running time is exponential in the number of occurrences of `min' and
  1602 `max', and `-' on `nat'.
  1603 
  1604 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1605 (negated) (in)equalities among the premises and the conclusion into
  1606 account (i.e. no compound formulae) and does not know about `min' and
  1607 `max', and `-' on `nat'. It is fast and is used automatically by the
  1608 simplifier.
  1609 
  1610 NB: At the moment, these decision procedures do not cope with mixed
  1611 nat/int formulae where the two parts interact, such as `m < n ==>
  1612 int(m) < int(n)'.
  1613 
  1614 * HOL/Numeral provides a generic theory of numerals (encoded
  1615 efficiently as bit strings); setup for types nat/int/real is in place;
  1616 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1617 int, existing theories and proof scripts may require a few additional
  1618 type constraints;
  1619 
  1620 * integer division and remainder can now be performed on constant
  1621 arguments;
  1622 
  1623 * many properties of integer multiplication, division and remainder
  1624 are now available;
  1625 
  1626 * An interface to the Stanford Validity Checker (SVC) is available through the
  1627 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1628 are proved automatically.  SVC must be installed separately, and its results
  1629 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1630 invocation of the underlying oracle).  For SVC see
  1631   http://verify.stanford.edu/SVC
  1632 
  1633 * IsaMakefile: the HOL-Real target now builds an actual image;
  1634 
  1635 
  1636 ** HOL misc **
  1637 
  1638 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1639 (in Isabelle/Isar) -- by Gertrud Bauer;
  1640 
  1641 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1642 analysis for assembly languages with subtypes;
  1643 
  1644 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1645 -- avoids syntactic ambiguities and treats state, transition, and
  1646 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1647 changed syntax and (many) tactics;
  1648 
  1649 * HOL/inductive: Now also handles more general introduction rules such
  1650   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1651   theorems are now maintained within the theory (maintained via the
  1652   "mono" attribute);
  1653 
  1654 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1655   (using function types) such as
  1656 
  1657   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1658 
  1659 * HOL/record: record_simproc (part of the default simpset) takes care
  1660 of selectors applied to updated records; record_split_tac is no longer
  1661 part of the default claset; update_defs may now be removed from the
  1662 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1663 
  1664   claset_ref () := claset() addSWrapper record_split_wrapper;
  1665   Delsimprocs [record_simproc]
  1666 
  1667 * HOL/typedef: fixed type inference for representing set; type
  1668 arguments now have to occur explicitly on the rhs as type constraints;
  1669 
  1670 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1671 names rather than an ML expression;
  1672 
  1673 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1674 supplied later.  Program schemes can be defined, such as
  1675     "While B C s = (if B s then While B C (C s) else s)"
  1676 where the well-founded relation can be chosen after B and C have been given.
  1677 
  1678 * HOL/List: the constructors of type list are now Nil and Cons;
  1679 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1680 course, ML tools referring to List.list.op # etc. have to be adapted;
  1681 
  1682 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1683 disabled by default; run isabelle with option -m HOL to get back to
  1684 the original Gordon/HOL-style output;
  1685 
  1686 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1687 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1688 
  1689 * HOL basic syntax simplified (more orthogonal): all variants of
  1690 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1691 Eps operator is provided as well: "SOME x. P[x]";
  1692 
  1693 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1694 
  1695 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1696 thus available for user theories;
  1697 
  1698 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1699 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1700 time;
  1701 
  1702 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1703 several times and then mp;
  1704 
  1705 
  1706 *** LK ***
  1707 
  1708 * the notation <<...>> is now available as a notation for sequences of
  1709 formulas;
  1710 
  1711 * the simplifier is now installed
  1712 
  1713 * the axiom system has been generalized (thanks to Soren Heilmann)
  1714 
  1715 * the classical reasoner now has a default rule database
  1716 
  1717 
  1718 *** ZF ***
  1719 
  1720 * new primrec section allows primitive recursive functions to be given
  1721 directly (as in HOL) over datatypes and the natural numbers;
  1722 
  1723 * new tactics induct_tac and exhaust_tac for induction (or case
  1724 analysis) over datatypes and the natural numbers;
  1725 
  1726 * the datatype declaration of type T now defines the recursor T_rec;
  1727 
  1728 * simplification automatically does freeness reasoning for datatype
  1729 constructors;
  1730 
  1731 * automatic type-inference, with AddTCs command to insert new
  1732 type-checking rules;
  1733 
  1734 * datatype introduction rules are now added as Safe Introduction rules
  1735 to the claset;
  1736 
  1737 * the syntax "if P then x else y" is now available in addition to
  1738 if(P,x,y);
  1739 
  1740 
  1741 *** Internal programming interfaces ***
  1742 
  1743 * tuned simplifier trace output; new flag debug_simp;
  1744 
  1745 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1746 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1747 
  1748 * AxClass.axclass_tac lost the theory argument;
  1749 
  1750 * tuned current_goals_markers semantics: begin / end goal avoids
  1751 printing empty lines;
  1752 
  1753 * removed prs and prs_fn hook, which was broken because it did not
  1754 include \n in its semantics, forcing writeln to add one
  1755 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1756 string -> unit if you really want to output text without newline;
  1757 
  1758 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1759 plain output, interface builders may have to enable 'isabelle_font'
  1760 mode to get Isabelle font glyphs as before;
  1761 
  1762 * refined token_translation interface; INCOMPATIBILITY: output length
  1763 now of type real instead of int;
  1764 
  1765 * theory loader actions may be traced via new ThyInfo.add_hook
  1766 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1767 your own database of information attached to *whole* theories -- as
  1768 opposed to intra-theory data slots offered via TheoryDataFun;
  1769 
  1770 * proper handling of dangling sort hypotheses (at last!);
  1771 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1772 extra sort hypotheses that can be witnessed from the type signature;
  1773 the force_strip_shyps flag is gone, any remaining shyps are simply
  1774 left in the theorem (with a warning issued by strip_shyps_warning);
  1775 
  1776 
  1777 
  1778 New in Isabelle98-1 (October 1998)
  1779 ----------------------------------
  1780 
  1781 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1782 
  1783 * several changes of automated proof tools;
  1784 
  1785 * HOL: major changes to the inductive and datatype packages, including
  1786 some minor incompatibilities of theory syntax;
  1787 
  1788 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1789 called `inj_on';
  1790 
  1791 * HOL: removed duplicate thms in Arith:
  1792   less_imp_add_less  should be replaced by  trans_less_add1
  1793   le_imp_add_le      should be replaced by  trans_le_add1
  1794 
  1795 * HOL: unary minus is now overloaded (new type constraints may be
  1796 required);
  1797 
  1798 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1799 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1800 now taken as an integer constant.
  1801 
  1802 * Pure: ML function 'theory_of' renamed to 'theory';
  1803 
  1804 
  1805 *** Proof tools ***
  1806 
  1807 * Simplifier:
  1808   1. Asm_full_simp_tac is now more aggressive.
  1809      1. It will sometimes reorient premises if that increases their power to
  1810         simplify.
  1811      2. It does no longer proceed strictly from left to right but may also
  1812         rotate premises to achieve further simplification.
  1813      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1814      old Asm_full_simp_tac in that it does not rotate premises.
  1815   2. The simplifier now knows a little bit about nat-arithmetic.
  1816 
  1817 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1818 allows for selected deletion of wrappers, by introduction of names for
  1819 wrapper functionals.  This implies that addbefore, addSbefore,
  1820 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1821 and that adding two tactics with the same name overwrites the first
  1822 one (emitting a warning).
  1823   type wrapper = (int -> tactic) -> (int -> tactic)
  1824   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1825   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1826   delWrapper, delSWrapper: claset *  string            -> claset
  1827   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1828 
  1829 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1830 semantics; addbefore now affects only the unsafe part of step_tac
  1831 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1832 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1833 by Force_tac;
  1834 
  1835 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1836 compWrapper; added safe wrapper (and access functions for it);
  1837 
  1838 * HOL/split_all_tac is now much faster and fails if there is nothing
  1839 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1840 and the names of the automatically generated variables have changed.
  1841 split_all_tac has moved within claset() from unsafe wrappers to safe
  1842 wrappers, which means that !!-bound variables are split much more
  1843 aggressively, and safe_tac and clarify_tac now split such variables.
  1844 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1845 Note: the same holds for record_split_tac, which does the job of
  1846 split_all_tac for record fields.
  1847 
  1848 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1849 permanently to the default simpset using Addsplits just like
  1850 Addsimps. They can be removed via Delsplits just like
  1851 Delsimps. Lower-case versions are also available.
  1852 
  1853 * HOL/Simplifier: The rule split_if is now part of the default
  1854 simpset. This means that the simplifier will eliminate all occurrences
  1855 of if-then-else in the conclusion of a goal. To prevent this, you can
  1856 either remove split_if completely from the default simpset by
  1857 `Delsplits [split_if]' or remove it in a specific call of the
  1858 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1859 other case splitting rules to/from the default simpset: every datatype
  1860 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1861 t is the name of the datatype).
  1862 
  1863 * Classical reasoner / Simplifier combination: new force_tac (and
  1864 derivatives Force_tac, force) combines rewriting and classical
  1865 reasoning (and whatever other tools) similarly to auto_tac, but is
  1866 aimed to solve the given subgoal completely.
  1867 
  1868 
  1869 *** General ***
  1870 
  1871 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1872 and `goalw': the theory is no longer needed as an explicit argument -
  1873 the current theory context is used; assumptions are no longer returned
  1874 at the ML-level unless one of them starts with ==> or !!; it is
  1875 recommended to convert to these new commands using isatool fixgoal
  1876 (backup your sources first!);
  1877 
  1878 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1879 the current theory context, and 'theory' to lookup stored theories;
  1880 
  1881 * new theory section 'locale' for declaring constants, assumptions and
  1882 definitions that have local scope;
  1883 
  1884 * new theory section 'nonterminals' for purely syntactic types;
  1885 
  1886 * new theory section 'setup' for generic ML setup functions
  1887 (e.g. package initialization);
  1888 
  1889 * the distribution now includes Isabelle icons: see
  1890 lib/logo/isabelle-{small,tiny}.xpm;
  1891 
  1892 * isatool install - install binaries with absolute references to
  1893 ISABELLE_HOME/bin;
  1894 
  1895 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1896 
  1897 * print mode 'emacs' reserved for Isamode;
  1898 
  1899 * support multiple print (ast) translations per constant name;
  1900 
  1901 * theorems involving oracles are now printed with a suffixed [!];
  1902 
  1903 
  1904 *** HOL ***
  1905 
  1906 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1907 
  1908 * HOL/inductive package reorganized and improved: now supports mutual
  1909 definitions such as
  1910 
  1911   inductive EVEN ODD
  1912     intrs
  1913       null "0 : EVEN"
  1914       oddI "n : EVEN ==> Suc n : ODD"
  1915       evenI "n : ODD ==> Suc n : EVEN"
  1916 
  1917 new theorem list "elims" contains an elimination rule for each of the
  1918 recursive sets; inductive definitions now handle disjunctive premises
  1919 correctly (also ZF);
  1920 
  1921 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1922 "mutual_induct" no longer exists - the induction rule is always
  1923 contained in "induct";
  1924 
  1925 
  1926 * HOL/datatype package re-implemented and greatly improved: now
  1927 supports mutually recursive datatypes such as
  1928 
  1929   datatype
  1930     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1931             | SUM ('a aexp) ('a aexp)
  1932             | DIFF ('a aexp) ('a aexp)
  1933             | NUM 'a
  1934   and
  1935     'a bexp = LESS ('a aexp) ('a aexp)
  1936             | AND ('a bexp) ('a bexp)
  1937             | OR ('a bexp) ('a bexp)
  1938 
  1939 as well as indirectly recursive datatypes such as
  1940 
  1941   datatype
  1942     ('a, 'b) term = Var 'a
  1943                   | App 'b ((('a, 'b) term) list)
  1944 
  1945 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1946 induction on mutually / indirectly recursive datatypes.
  1947 
  1948 Primrec equations are now stored in theory and can be accessed via
  1949 <function_name>.simps.
  1950 
  1951 INCOMPATIBILITIES:
  1952 
  1953   - Theories using datatypes must now have theory Datatype as an
  1954     ancestor.
  1955   - The specific <typename>.induct_tac no longer exists - use the
  1956     generic induct_tac instead.
  1957   - natE has been renamed to nat.exhaust - use exhaust_tac
  1958     instead of res_inst_tac ... natE. Note that the variable
  1959     names in nat.exhaust differ from the names in natE, this
  1960     may cause some "fragile" proofs to fail.
  1961   - The theorems split_<typename>_case and split_<typename>_case_asm
  1962     have been renamed to <typename>.split and <typename>.split_asm.
  1963   - Since default sorts of type variables are now handled correctly,
  1964     some datatype definitions may have to be annotated with explicit
  1965     sort constraints.
  1966   - Primrec definitions no longer require function name and type
  1967     of recursive argument.
  1968 
  1969 Consider using isatool fixdatatype to adapt your theories and proof
  1970 scripts to the new package (backup your sources first!).
  1971 
  1972 
  1973 * HOL/record package: considerably improved implementation; now
  1974 includes concrete syntax for record types, terms, updates; theorems
  1975 for surjective pairing and splitting !!-bound record variables; proof
  1976 support is as follows:
  1977 
  1978   1) standard conversions (selectors or updates applied to record
  1979 constructor terms) are part of the standard simpset;
  1980 
  1981   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1982 made part of standard simpset and claset via addIffs;
  1983 
  1984   3) a tactic for record field splitting (record_split_tac) is part of
  1985 the standard claset (addSWrapper);
  1986 
  1987 To get a better idea about these rules you may retrieve them via
  1988 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1989 the name of your record type.
  1990 
  1991 The split tactic 3) conceptually simplifies by the following rule:
  1992 
  1993   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1994 
  1995 Thus any record variable that is bound by meta-all will automatically
  1996 blow up into some record constructor term, consequently the
  1997 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1998 solve record problems automatically.
  1999 
  2000 
  2001 * reorganized the main HOL image: HOL/Integ and String loaded by
  2002 default; theory Main includes everything;
  2003 
  2004 * automatic simplification of integer sums and comparisons, using cancellation;
  2005 
  2006 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2007 
  2008 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2009 
  2010 * many new identities for unions, intersections, set difference, etc.;
  2011 
  2012 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2013 called split_if, split_split, split_sum_case and split_nat_case (to go
  2014 with add/delsplits);
  2015 
  2016 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2017 (?x::unit) = (); this is made part of the default simpset, which COULD
  2018 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2019 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2020 unit_abs_eta_conv is added in order to counter the effect of
  2021 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2022 %u.f();
  2023 
  2024 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2025 makes more sense);
  2026 
  2027 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2028   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2029   disjointness reasoning but breaking a few old proofs.
  2030 
  2031 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2032 to 'converse' from 'inverse' (for compatibility with ZF and some
  2033 literature);
  2034 
  2035 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2036 the well-founded relation;
  2037 
  2038 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2039     Compl A.  The "Compl" syntax remains available as input syntax for this
  2040     release ONLY.
  2041 
  2042 * HOL/Update: new theory of function updates:
  2043     f(a:=b) == %x. if x=a then b else f x
  2044 may also be iterated as in f(a:=b,c:=d,...);
  2045 
  2046 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2047 
  2048 * HOL/List:
  2049   - new function list_update written xs[i:=v] that updates the i-th
  2050     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2051   - new function `upt' written [i..j(] which generates the list
  2052     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2053     bound write [i..j], which is a shorthand for [i..j+1(].
  2054   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2055 
  2056 * HOL/Arith:
  2057   - removed 'pred' (predecessor) function;
  2058   - generalized some theorems about n-1;
  2059   - many new laws about "div" and "mod";
  2060   - new laws about greatest common divisors (see theory ex/Primes);
  2061 
  2062 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2063 instead of "inverse";
  2064 
  2065 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2066   of the multiset ordering;
  2067 
  2068 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2069   (not included by default);
  2070 
  2071 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2072 
  2073 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2074   programs, i.e. different program variables may have different types.
  2075 
  2076 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2077   [previously, this check worked only if the rewrite rule was unconditional]
  2078   Now rew can involve either definitions or equalities (either == or =).
  2079 
  2080 
  2081 *** ZF ***
  2082 
  2083 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2084   only the theorems proved on ZF.ML;
  2085 
  2086 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2087   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2088   disjointness reasoning but breaking a few old proofs.
  2089 
  2090 * ZF/Update: new theory of function updates
  2091     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2092   may also be iterated as in f(a:=b,c:=d,...);
  2093 
  2094 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2095 
  2096 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2097   [previously, this check worked only if the rewrite rule was unconditional]
  2098   Now rew can involve either definitions or equalities (either == or =).
  2099 
  2100 * case_tac provided for compatibility with HOL
  2101     (like the old excluded_middle_tac, but with subgoals swapped)
  2102 
  2103 
  2104 *** Internal programming interfaces ***
  2105 
  2106 * Pure: several new basic modules made available for general use, see
  2107 also src/Pure/README;
  2108 
  2109 * improved the theory data mechanism to support encapsulation (data
  2110 kind name replaced by private Object.kind, acting as authorization
  2111 key); new type-safe user interface via functor TheoryDataFun; generic
  2112 print_data function becomes basically useless;
  2113 
  2114 * removed global_names compatibility flag -- all theory declarations
  2115 are qualified by default;
  2116 
  2117 * module Pure/Syntax now offers quote / antiquote translation
  2118 functions (useful for Hoare logic etc. with implicit dependencies);
  2119 see HOL/ex/Antiquote for an example use;
  2120 
  2121 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2122 cterm -> thm;
  2123 
  2124 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2125 subgoal;
  2126 
  2127 * Display.print_goals function moved to Locale.print_goals;
  2128 
  2129 * standard print function for goals supports current_goals_markers
  2130 variable for marking begin of proof, end of proof, start of goal; the
  2131 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2132 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2133 for example;
  2134 
  2135 
  2136 
  2137 New in Isabelle98 (January 1998)
  2138 --------------------------------
  2139 
  2140 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2141 
  2142 * changed lexical syntax of terms / types: dots made part of long
  2143 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2144 
  2145 * simpset (and claset) reference variable replaced by functions
  2146 simpset / simpset_ref;
  2147 
  2148 * no longer supports theory aliases (via merge) and non-trivial
  2149 implicit merge of thms' signatures;
  2150 
  2151 * most internal names of constants changed due to qualified names;
  2152 
  2153 * changed Pure/Sequence interface (see Pure/seq.ML);
  2154 
  2155 
  2156 *** General Changes ***
  2157 
  2158 * hierachically structured name spaces (for consts, types, axms, thms
  2159 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2160 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2161 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2162 long_names for fully qualified output names; NOTE: ML programs
  2163 (special tactics, packages etc.) referring to internal names may have
  2164 to be adapted to cope with fully qualified names; in case of severe
  2165 backward campatibility problems try setting 'global_names' at compile
  2166 time to have enrything declared within a flat name space; one may also
  2167 fine tune name declarations in theories via the 'global' and 'local'
  2168 section;
  2169 
  2170 * reimplemented the implicit simpset and claset using the new anytype
  2171 data filed in signatures; references simpset:simpset ref etc. are
  2172 replaced by functions simpset:unit->simpset and
  2173 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2174 to patch your ML files accordingly;
  2175 
  2176 * HTML output now includes theory graph data for display with Java
  2177 applet or isatool browser; data generated automatically via isatool
  2178 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2179 
  2180 * defs may now be conditional; improved rewrite_goals_tac to handle
  2181 conditional equations;
  2182 
  2183 * defs now admits additional type arguments, using TYPE('a) syntax;
  2184 
  2185 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2186 creates a new theory node; implicit merge of thms' signatures is
  2187 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2188 transfer:theory->thm->thm in (rare) cases;
  2189 
  2190 * improved handling of draft signatures / theories; draft thms (and
  2191 ctyps, cterms) are automatically promoted to real ones;
  2192 
  2193 * slightly changed interfaces for oracles: admit many per theory, named
  2194 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2195 
  2196 * print_goals: optional output of const types (set show_consts and
  2197 show_types);
  2198 
  2199 * improved output of warnings (###) and errors (***);
  2200 
  2201 * subgoal_tac displays a warning if the new subgoal has type variables;
  2202 
  2203 * removed old README and Makefiles;
  2204 
  2205 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2206 
  2207 * removed obsolete init_pps and init_database;
  2208 
  2209 * deleted the obsolete tactical STATE, which was declared by
  2210     fun STATE tacfun st = tacfun st st;
  2211 
  2212 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2213 (which abbreviates $HOME);
  2214 
  2215 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2216 use isatool fixseq to adapt your ML programs (this works for fully
  2217 qualified references to the Sequence structure only!);
  2218 
  2219 * use_thy no longer requires writable current directory; it always
  2220 reloads .ML *and* .thy file, if either one is out of date;
  2221 
  2222 
  2223 *** Classical Reasoner ***
  2224 
  2225 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2226 tactics that use classical reasoning to simplify a subgoal without
  2227 splitting it into several subgoals;
  2228 
  2229 * Safe_tac: like safe_tac but uses the default claset;
  2230 
  2231 
  2232 *** Simplifier ***
  2233 
  2234 * added simplification meta rules:
  2235     (asm_)(full_)simplify: simpset -> thm -> thm;
  2236 
  2237 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2238 logics (again);
  2239 
  2240 * added prems argument to simplification procedures;
  2241 
  2242 * HOL, FOL, ZF: added infix function `addsplits':
  2243   instead of `<simpset> setloop (split_tac <thms>)'
  2244   you can simply write `<simpset> addsplits <thms>'
  2245 
  2246 
  2247 *** Syntax ***
  2248 
  2249 * TYPE('a) syntax for type reflection terms;
  2250 
  2251 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2252 
  2253 * pretty printer: changed order of mixfix annotation preference (again!);
  2254 
  2255 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2256 
  2257 
  2258 *** HOL ***
  2259 
  2260 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2261   with `addloop' of the simplifier to faciliate case splitting in premises.
  2262 
  2263 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2264 
  2265 * HOL/Auth: new protocol proofs including some for the Internet
  2266   protocol TLS;
  2267 
  2268 * HOL/Map: new theory of `maps' a la VDM;
  2269 
  2270 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2271 cancelling out common nat summands from =, <, <= (in)equalities, or
  2272 differences; simplification procedures nat_cancel_factor for
  2273 cancelling common factor from =, <, <= (in)equalities over natural
  2274 sums; nat_cancel contains both kinds of procedures, it is installed by
  2275 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2276 
  2277 * HOL/simplifier: terms of the form
  2278   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2279   are rewritten to
  2280   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2281   and those of the form
  2282   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2283   are rewritten to
  2284   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2285 
  2286 * HOL/datatype
  2287   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2288 
  2289   P(t_case f1 ... fn x) =
  2290      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2291         ...
  2292        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2293      )
  2294 
  2295   and a theorem `split_t_case_asm' of the form
  2296 
  2297   P(t_case f1 ... fn x) =
  2298     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2299         ...
  2300        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2301      )
  2302   which can be added to a simpset via `addsplits'. The existing theorems
  2303   expand_list_case and expand_option_case have been renamed to
  2304   split_list_case and split_option_case.
  2305 
  2306 * HOL/Arithmetic:
  2307   - `pred n' is automatically converted to `n-1'.
  2308     Users are strongly encouraged not to use `pred' any longer,
  2309     because it will disappear altogether at some point.
  2310   - Users are strongly encouraged to write "0 < n" rather than
  2311     "n ~= 0". Theorems and proof tools have been modified towards this
  2312     `standard'.
  2313 
  2314 * HOL/Lists:
  2315   the function "set_of_list" has been renamed "set" (and its theorems too);
  2316   the function "nth" now takes its arguments in the reverse order and
  2317   has acquired the infix notation "!" as in "xs!n".
  2318 
  2319 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2320 
  2321 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2322   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2323 
  2324 * HOL/record: extensible records with schematic structural subtyping
  2325 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2326 still lacks various theorems and concrete record syntax;
  2327 
  2328 
  2329 *** HOLCF ***
  2330 
  2331 * removed "axioms" and "generated by" sections;
  2332 
  2333 * replaced "ops" section by extended "consts" section, which is capable of
  2334   handling the continuous function space "->" directly;
  2335 
  2336 * domain package:
  2337   . proves theorems immediately and stores them in the theory,
  2338   . creates hierachical name space,
  2339   . now uses normal mixfix annotations (instead of cinfix...),
  2340   . minor changes to some names and values (for consistency),
  2341   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2342   . separator between mutual domain defs: changed "," to "and",
  2343   . improved handling of sort constraints;  now they have to
  2344     appear on the left-hand side of the equations only;
  2345 
  2346 * fixed LAM <x,y,zs>.b syntax;
  2347 
  2348 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2349 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2350 
  2351 
  2352 *** FOL and ZF ***
  2353 
  2354 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2355   with `addloop' of the simplifier to faciliate case splitting in premises.
  2356 
  2357 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2358 in HOL, they strip ALL and --> from proved theorems;
  2359 
  2360 
  2361 
  2362 New in Isabelle94-8 (May 1997)
  2363 ------------------------------
  2364 
  2365 *** General Changes ***
  2366 
  2367 * new utilities to build / run / maintain Isabelle etc. (in parts
  2368 still somewhat experimental); old Makefiles etc. still functional;
  2369 
  2370 * new 'Isabelle System Manual';
  2371 
  2372 * INSTALL text, together with ./configure and ./build scripts;
  2373 
  2374 * reimplemented type inference for greater efficiency, better error
  2375 messages and clean internal interface;
  2376 
  2377 * prlim command for dealing with lots of subgoals (an easier way of
  2378 setting goals_limit);
  2379 
  2380 
  2381 *** Syntax ***
  2382 
  2383 * supports alternative (named) syntax tables (parser and pretty
  2384 printer); internal interface is provided by add_modesyntax(_i);
  2385 
  2386 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2387 be used in conjunction with the Isabelle symbol font; uses the
  2388 "symbols" syntax table;
  2389 
  2390 * added token_translation interface (may translate name tokens in
  2391 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2392 the current print_mode); IMPORTANT: user print translation functions
  2393 are responsible for marking newly introduced bounds
  2394 (Syntax.mark_boundT);
  2395 
  2396 * token translations for modes "xterm" and "xterm_color" that display
  2397 names in bold, underline etc. or colors (which requires a color
  2398 version of xterm);
  2399 
  2400 * infixes may now be declared with names independent of their syntax;
  2401 
  2402 * added typed_print_translation (like print_translation, but may
  2403 access type of constant);
  2404 
  2405 
  2406 *** Classical Reasoner ***
  2407 
  2408 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2409 some limitations.  Blast_tac...
  2410   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2411   + ignores elimination rules that don't have the correct format
  2412         (the conclusion MUST be a formula variable)
  2413   + ignores types, which can make HOL proofs fail
  2414   + rules must not require higher-order unification, e.g. apply_type in ZF
  2415     [message "Function Var's argument not a bound variable" relates to this]
  2416   + its proof strategy is more general but can actually be slower
  2417 
  2418 * substitution with equality assumptions no longer permutes other
  2419 assumptions;
  2420 
  2421 * minor changes in semantics of addafter (now called addaltern); renamed
  2422 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2423 (and access functions for it);
  2424 
  2425 * improved combination of classical reasoner and simplifier:
  2426   + functions for handling clasimpsets
  2427   + improvement of addss: now the simplifier is called _after_ the
  2428     safe steps.
  2429   + safe variant of addss called addSss: uses safe simplifications
  2430     _during_ the safe steps. It is more complete as it allows multiple
  2431     instantiations of unknowns (e.g. with slow_tac).
  2432 
  2433 *** Simplifier ***
  2434 
  2435 * added interface for simplification procedures (functions that
  2436 produce *proven* rewrite rules on the fly, depending on current
  2437 redex);
  2438 
  2439 * ordering on terms as parameter (used for ordered rewriting);
  2440 
  2441 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2442 
  2443 * the solver is now split into a safe and an unsafe part.
  2444 This should be invisible for the normal user, except that the
  2445 functions setsolver and addsolver have been renamed to setSolver and
  2446 addSolver; added safe_asm_full_simp_tac;
  2447 
  2448 
  2449 *** HOL ***
  2450 
  2451 * a generic induction tactic `induct_tac' which works for all datatypes and
  2452 also for type `nat';
  2453 
  2454 * a generic case distinction tactic `exhaust_tac' which works for all
  2455 datatypes and also for type `nat';
  2456 
  2457 * each datatype comes with a function `size';
  2458 
  2459 * patterns in case expressions allow tuple patterns as arguments to
  2460 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2461 
  2462 * primrec now also works with type nat;
  2463 
  2464 * recdef: a new declaration form, allows general recursive functions to be
  2465 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2466 
  2467 * the constant for negation has been renamed from "not" to "Not" to
  2468 harmonize with FOL, ZF, LK, etc.;
  2469 
  2470 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2471 infinite lists;
  2472 
  2473 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2474 
  2475 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2476 problems in commutative rings, using axiomatic type classes for + and *;
  2477 
  2478 * more examples in HOL/MiniML and HOL/Auth;
  2479 
  2480 * more default rewrite rules for quantifiers, union/intersection;
  2481 
  2482 * a new constant `arbitrary == @x.False';
  2483 
  2484 * HOLCF/IOA replaces old HOL/IOA;
  2485 
  2486 * HOLCF changes: derived all rules and arities
  2487   + axiomatic type classes instead of classes
  2488   + typedef instead of faking type definitions
  2489   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2490   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2491   + eliminated the types void, one, tr
  2492   + use unit lift and bool lift (with translations) instead of one and tr
  2493   + eliminated blift from Lift3.thy (use Def instead of blift)
  2494   all eliminated rules are derived as theorems --> no visible changes ;
  2495 
  2496 
  2497 *** ZF ***
  2498 
  2499 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2500 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2501 as ZF_cs addSIs [equalityI];
  2502 
  2503 
  2504 
  2505 New in Isabelle94-7 (November 96)
  2506 ---------------------------------
  2507 
  2508 * allowing negative levels (as offsets) in prlev and choplev;
  2509 
  2510 * super-linear speedup for large simplifications;
  2511 
  2512 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2513 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2514 FAIL); can suppress it using the command Delsimps (ex_simps @
  2515 all_simps); De Morgan laws are also now included, by default;
  2516 
  2517 * improved printing of ==>  :  ~:
  2518 
  2519 * new object-logic "Sequents" adds linear logic, while replacing LK
  2520 and Modal (thanks to Sara Kalvala);
  2521 
  2522 * HOL/Auth: correctness proofs for authentication protocols;
  2523 
  2524 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2525 examples on HOL/Auth);
  2526 
  2527 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2528 the rewriter and classical reasoner simultaneously;
  2529 
  2530 * function uresult no longer returns theorems in "standard" format;
  2531 regain previous version by: val uresult = standard o uresult;
  2532 
  2533 
  2534 
  2535 New in Isabelle94-6
  2536 -------------------
  2537 
  2538 * oracles -- these establish an interface between Isabelle and trusted
  2539 external reasoners, which may deliver results as theorems;
  2540 
  2541 * proof objects (in particular record all uses of oracles);
  2542 
  2543 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2544 
  2545 * "constdefs" section in theory files;
  2546 
  2547 * "primrec" section (HOL) no longer requires names;
  2548 
  2549 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2550 
  2551 
  2552 
  2553 New in Isabelle94-5
  2554 -------------------
  2555 
  2556 * reduced space requirements;
  2557 
  2558 * automatic HTML generation from theories;
  2559 
  2560 * theory files no longer require "..." (quotes) around most types;
  2561 
  2562 * new examples, including two proofs of the Church-Rosser theorem;
  2563 
  2564 * non-curried (1994) version of HOL is no longer distributed;
  2565 
  2566 
  2567 
  2568 New in Isabelle94-4
  2569 -------------------
  2570 
  2571 * greatly reduced space requirements;
  2572 
  2573 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2574 
  2575 * searchable theorem database (see the section "Retrieving theorems" on
  2576 page 8 of the Reference Manual);
  2577 
  2578 * new examples, including Grabczewski's monumental case study of the
  2579 Axiom of Choice;
  2580 
  2581 * The previous version of HOL renamed to Old_HOL;
  2582 
  2583 * The new version of HOL (previously called CHOL) uses a curried syntax
  2584 for functions.  Application looks like f a b instead of f(a,b);
  2585 
  2586 * Mutually recursive inductive definitions finally work in HOL;
  2587 
  2588 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2589 translates to the operator "split";
  2590 
  2591 
  2592 
  2593 New in Isabelle94-3
  2594 -------------------
  2595 
  2596 * new infix operator, addss, allowing the classical reasoner to
  2597 perform simplification at each step of its search.  Example:
  2598         fast_tac (cs addss ss)
  2599 
  2600 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2601 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2602 look like (a,b) instead of <a,b>;
  2603 
  2604 * PLEASE NOTE: CHOL will eventually replace HOL!
  2605 
  2606 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2607 It translates to the operator "split".  A new theory of integers is available;
  2608 
  2609 * In ZF, integer numerals now denote two's-complement binary integers.
  2610 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2611 
  2612 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2613 of the Axiom of Choice;
  2614 
  2615 
  2616 
  2617 New in Isabelle94-2
  2618 -------------------
  2619 
  2620 * Significantly faster resolution;
  2621 
  2622 * the different sections in a .thy file can now be mixed and repeated
  2623 freely;
  2624 
  2625 * Database of theorems for FOL, HOL and ZF.  New
  2626 commands including qed, qed_goal and bind_thm store theorems in the database.
  2627 
  2628 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2629 a given theory (thms_of), or find out what theory a theorem was proved in
  2630 (theory_of_thm);
  2631 
  2632 * Bugs fixed in the inductive definition and datatype packages;
  2633 
  2634 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2635 and HOL_dup_cs obsolete;
  2636 
  2637 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2638 have been removed;
  2639 
  2640 * Simpler definition of function space in ZF;
  2641 
  2642 * new results about cardinal and ordinal arithmetic in ZF;
  2643 
  2644 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2645 types;
  2646 
  2647 
  2648 $Id$