NEWS
author webertj
Thu Mar 11 13:34:13 2004 +0100 (2004-03-11)
changeset 14464 72ad5f2a3803
parent 14427 cea7d2f76112
child 14480 14b7923b3307
permissions -rw-r--r--
refute
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    10   Replaces linorder.ML.
    11 
    12 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    13   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    14   (\<a>...\<z>), are now considered normal letters, and can therefore
    15   be used anywhere where an ASCII letter (a...zA...Z) has until
    16   now. COMPATIBILITY: This obviously changes the parsing of some
    17   terms, especially where a symbol has been used as a binder, say
    18   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    19   as an identifier.  Fix it by inserting a space around former
    20   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    21   existing theory and ML files.
    22 
    23 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    24 
    25 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    26   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    27   a normal (but invisible) letter. For multiple letter subscripts repeat 
    28   \<^isub> like this: x\<^isub>1\<^isub>2. 
    29 
    30 * Pure: There are now sub-/superscripts that can span more than one
    31   character. Text between \<^bsub> and \<^esub> is set in subscript in
    32   PG and LaTeX, text between \<^bsup> and \<^esup> in superscript. The
    33   new control characters are not identifier parts.
    34 
    35 * Pure: Control-symbols of the form \<^raw...> will literally print the
    36   content of ... to the latex file instead of \isacntrl... . The ... 
    37   accepts all printable characters excluding the end bracket >.
    38 
    39 * Pure: Symbols may only start with one backslash: \<...>. \\<...> is no 
    40   longer accepted by the scanner.
    41 
    42 * Pure: Using new Isar command "finalconsts" (or the ML functions
    43   Theory.add_finals or Theory.add_finals_i) it is now possible to
    44   declare constants "final", which prevents their being given a definition
    45   later.  It is useful for constants whose behaviour is fixed axiomatically
    46   rather than definitionally, such as the meta-logic connectives.
    47 
    48 *** Isar ***
    49 
    50 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    51   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    52     locales are no longer forced to write Isar proof scripts.
    53     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    54     emulations.
    55   - INCOMPATIBILITY: names of variables to be instantiated may no
    56     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    57     This is consistent with the instantiation attribute "where".
    58 
    59 * Attributes "where" and "of":
    60   - Now take type variables of instantiated theorem into account when reading
    61     the instantiation string.  This fixes a bug that caused instantiated
    62     theorems to have too special types in some circumstances.
    63   - "where" permits explicit instantiations of type variables.
    64 
    65 * Calculation commands "moreover" and "also":
    66   Do not reset facts ("this") any more.
    67 
    68 * Locales:
    69   - Goal statements involving the context element "includes" no longer
    70     generate theorems with internal delta predicates (those ending on
    71     "_axioms") in the premise.
    72     Resolve particular premise with <locale>.intro to obtain old form.
    73   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    74     specification and "includes" elements in goal statement.
    75   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    76     [intro?] and [elim?] (respectively) by default.
    77 
    78 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    79   (Isar) contexts.
    80 
    81 *** HOL ***
    82 
    83 * Simplifier:
    84   - Much improved handling of linear and partial orders.
    85     Reasoners for linear and partial orders are set up for type classes
    86     "linorder" and "order" respectively, and are added to the default simpset
    87     as solvers.  This means that the simplifier can build transitivity chains
    88     to solve goals from the assumptions.
    89   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
    90     of blast or auto after simplification become unnecessary because the goal
    91     is solved by simplification already.
    92 
    93 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
    94     all proved in axiomatic type classes for semirings, rings and fields.
    95 
    96 * Numerics:
    97   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
    98     now formalized using the Ring_and_Field theory mentioned above. 
    99   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   100     than before, because now they are set up once in a generic manner.
   101   - INCOMPATIBILITY: many type-specific instances of laws proved in 
   102     Ring_and_Field are no longer available.
   103 
   104 * Type "rat" of the rational numbers is now available in HOL-Complex.
   105 
   106 * Records:
   107   - Record types are now by default printed with their type abbreviation
   108     instead of the list of all field types. This can be configured via
   109     the reference "print_record_type_abbr".
   110   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   111     (not enabled by default).
   112   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   113     EX x. x = sel r to True (not enabled by default).
   114   - Tactic "record_split_simp_tac" to split and simplify records added.
   115  
   116 * 'specification' command added, allowing for definition by
   117   specification.  There is also an 'ax_specification' command that
   118   introduces the new constants axiomatically.
   119 
   120 * arith(_tac) is now able to generate counterexamples for reals as well.
   121 
   122 * HOL-Algebra: new locale "ring" for non-commutative rings.
   123 
   124 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   125  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   126 
   127 * Unions and Intersections:
   128   The x-symbol output syntax of UN and INT has been changed
   129   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   130   i.e. the index formulae has become a subscript, like in normal math.
   131   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   132   The subscript version is also accepted as input syntax.
   133 
   134 * Unions and Intersections over Intervals:
   135   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   136   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   137   like in normal math, and corresponding versions for < and for intersection.
   138 
   139 * ML: the legacy theory structures Int and List have been removed. They had
   140   conflicted with ML Basis Library structures having the same names.
   141 
   142 * 'refute' command added to search for (finite) countermodels.  Only works
   143   for a fragment of HOL.  The installation of an external SAT solver is
   144   highly recommended.  See "HOL/Refute.thy" for details.
   145 
   146 
   147 New in Isabelle2003 (May 2003)
   148 --------------------------------
   149 
   150 *** General ***
   151 
   152 * Provers/simplifier:
   153 
   154   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   155     Assumptions are now subject to complete mutual simplification,
   156     not just from left to right. The simplifier now preserves
   157     the order of assumptions.
   158 
   159     Potential INCOMPATIBILITY:
   160 
   161     -- simp sometimes diverges where the old version did
   162        not, e.g. invoking simp on the goal
   163 
   164         [| P (f x); y = x; f x = f y |] ==> Q
   165 
   166        now gives rise to the infinite reduction sequence
   167 
   168         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   169 
   170        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   171        kind of problem.
   172 
   173     -- Tactics combining classical reasoner and simplification (such as auto)
   174        are also affected by this change, because many of them rely on
   175        simp. They may sometimes diverge as well or yield a different numbers
   176        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   177        in case of problems. Sometimes subsequent calls to the classical
   178        reasoner will fail because a preceeding call to the simplifier too
   179        eagerly simplified the goal, e.g. deleted redundant premises.
   180 
   181   - The simplifier trace now shows the names of the applied rewrite rules
   182 
   183   - You can limit the number of recursive invocations of the simplifier
   184     during conditional rewriting (where the simplifie tries to solve the
   185     conditions before applying the rewrite rule):
   186     ML "simp_depth_limit := n"
   187     where n is an integer. Thus you can force termination where previously
   188     the simplifier would diverge.
   189 
   190   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   191 
   192   - No longer aborts on failed congruence proof.  Instead, the
   193     congruence is ignored.
   194 
   195 * Pure: New generic framework for extracting programs from constructive
   196   proofs. See HOL/Extraction.thy for an example instantiation, as well
   197   as HOL/Extraction for some case studies.
   198 
   199 * Pure: The main goal of the proof state is no longer shown by default, only
   200 the subgoals. This behaviour is controlled by a new flag.
   201    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   202 (ML: Proof.show_main_goal).
   203 
   204 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   205 rules whose conclusion matches subgoal 1:
   206       PG menu: Isabelle/Isar -> Show me -> matching rules
   207 The rules are ordered by how closely they match the subgoal.
   208 In particular, rules that solve a subgoal outright are displayed first
   209 (or rather last, the way they are printed).
   210 (ML: ProofGeneral.print_intros())
   211 
   212 * Pure: New flag trace_unify_fail causes unification to print
   213 diagnostic information (PG: in trace buffer) when it fails. This is
   214 useful for figuring out why single step proofs like rule, erule or
   215 assumption failed.
   216 
   217 * Pure: Locale specifications now produce predicate definitions
   218 according to the body of text (covering assumptions modulo local
   219 definitions); predicate "loc_axioms" covers newly introduced text,
   220 while "loc" is cumulative wrt. all included locale expressions; the
   221 latter view is presented only on export into the global theory
   222 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   223 on the old view without predicates;
   224 
   225 * Pure: predefined locales "var" and "struct" are useful for sharing
   226 parameters (as in CASL, for example); just specify something like
   227 ``var x + var y + struct M'' as import;
   228 
   229 * Pure: improved thms_containing: proper indexing of facts instead of
   230 raw theorems; check validity of results wrt. current name space;
   231 include local facts of proof configuration (also covers active
   232 locales), cover fixed variables in index; may use "_" in term
   233 specification; an optional limit for the number of printed facts may
   234 be given (the default is 40);
   235 
   236 * Pure: disallow duplicate fact bindings within new-style theory files
   237 (batch-mode only);
   238 
   239 * Provers: improved induct method: assumptions introduced by case
   240 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   241 the goal statement); "foo" still refers to all facts collectively;
   242 
   243 * Provers: the function blast.overloaded has been removed: all constants
   244 are regarded as potentially overloaded, which improves robustness in exchange
   245 for slight decrease in efficiency;
   246 
   247 * Provers/linorder: New generic prover for transitivity reasoning over
   248 linear orders.  Note: this prover is not efficient!
   249 
   250 * Isar: preview of problems to finish 'show' now produce an error
   251 rather than just a warning (in interactive mode);
   252 
   253 
   254 *** HOL ***
   255 
   256 * arith(_tac)
   257 
   258  - Produces a counter example if it cannot prove a goal.
   259    Note that the counter example may be spurious if the goal is not a formula
   260    of quantifier-free linear arithmetic.
   261    In ProofGeneral the counter example appears in the trace buffer.
   262 
   263  - Knows about div k and mod k where k is a numeral of type nat or int.
   264 
   265  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   266    linear arithmetic fails. This takes account of quantifiers and divisibility.
   267    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   268 
   269 * simp's arithmetic capabilities have been enhanced a bit: it now
   270 takes ~= in premises into account (by performing a case split);
   271 
   272 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   273 are distributed over a sum of terms;
   274 
   275 * New tactic "trans_tac" and method "trans" instantiate
   276 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   277 "<=", "<" and "="). 
   278 
   279 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   280 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   281 
   282 * 'typedef' command has new option "open" to suppress the set
   283 definition;
   284 
   285 * functions Min and Max on finite sets have been introduced (theory
   286 Finite_Set);
   287 
   288 * attribute [symmetric] now works for relations as well; it turns
   289 (x,y) : R^-1 into (y,x) : R, and vice versa;
   290 
   291 * induct over a !!-quantified statement (say !!x1..xn):
   292   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   293 
   294 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   295 %x. None. Warning: empty_def now refers to the previously hidden definition
   296 of the empty set.
   297 
   298 * Algebra: formalization of classical algebra.  Intended as base for
   299 any algebraic development in Isabelle.  Currently covers group theory
   300 (up to Sylow's theorem) and ring theory (Universal Property of
   301 Univariate Polynomials).  Contributions welcome;
   302 
   303 * GroupTheory: deleted, since its material has been moved to Algebra;
   304 
   305 * Complex: new directory of the complex numbers with numeric constants, 
   306 nonstandard complex numbers, and some complex analysis, standard and 
   307 nonstandard (Jacques Fleuriot);
   308 
   309 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   310 
   311 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   312 Fleuriot);
   313 
   314 * Real/HahnBanach: updated and adapted to locales;
   315 
   316 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   317 Gray and Kramer);
   318 
   319 * UNITY: added the Meier-Sanders theory of progress sets;
   320 
   321 * MicroJava: bytecode verifier and lightweight bytecode verifier
   322 as abstract algorithms, instantiated to the JVM;
   323 
   324 * Bali: Java source language formalization. Type system, operational
   325 semantics, axiomatic semantics. Supported language features:
   326 classes, interfaces, objects,virtual methods, static methods,
   327 static/instance fields, arrays, access modifiers, definite
   328 assignment, exceptions.
   329 
   330 
   331 *** ZF ***
   332 
   333 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   334 universe, etc.);
   335 
   336 * Main ZF: virtually all theories converted to new-style format;
   337 
   338 
   339 *** ML ***
   340 
   341 * Pure: Tactic.prove provides sane interface for internal proofs;
   342 omits the infamous "standard" operation, so this is more appropriate
   343 than prove_goalw_cterm in many situations (e.g. in simprocs);
   344 
   345 * Pure: improved error reporting of simprocs;
   346 
   347 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   348 up simprocs;
   349 
   350 
   351 *** Document preparation ***
   352 
   353 * uses \par instead of \\ for line breaks in theory text. This may
   354 shift some page breaks in large documents. To get the old behaviour
   355 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   356 
   357 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   358 other packages
   359 
   360 * \<euro> now needs package babel/greek instead of marvosym (which
   361 broke \Rightarrow)
   362 
   363 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   364 textcomp package)
   365 
   366 
   367 New in Isabelle2002 (March 2002)
   368 --------------------------------
   369 
   370 *** Document preparation ***
   371 
   372 * greatly simplified document preparation setup, including more
   373 graceful interpretation of isatool usedir -i/-d/-D options, and more
   374 instructive isatool mkdir; users should basically be able to get
   375 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   376 users may run a separate document processing stage manually like this:
   377 "isatool usedir -D output HOL Test && isatool document Test/output";
   378 
   379 * theory dependency graph may now be incorporated into documents;
   380 isatool usedir -g true will produce session_graph.eps/.pdf for use
   381 with \includegraphics of LaTeX;
   382 
   383 * proper spacing of consecutive markup elements, especially text
   384 blocks after section headings;
   385 
   386 * support bold style (for single symbols only), input syntax is like
   387 this: "\<^bold>\<alpha>" or "\<^bold>A";
   388 
   389 * \<bullet> is now output as bold \cdot by default, which looks much
   390 better in printed text;
   391 
   392 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   393 note that these symbols are currently unavailable in Proof General /
   394 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   395 
   396 * isatool latex no longer depends on changed TEXINPUTS, instead
   397 isatool document copies the Isabelle style files to the target
   398 location;
   399 
   400 
   401 *** Isar ***
   402 
   403 * Pure/Provers: improved proof by cases and induction;
   404   - 'case' command admits impromptu naming of parameters (such as
   405     "case (Suc n)");
   406   - 'induct' method divinates rule instantiation from the inductive
   407     claim; no longer requires excessive ?P bindings for proper
   408     instantiation of cases;
   409   - 'induct' method properly enumerates all possibilities of set/type
   410     rules; as a consequence facts may be also passed through *type*
   411     rules without further ado;
   412   - 'induct' method now derives symbolic cases from the *rulified*
   413     rule (before it used to rulify cases stemming from the internal
   414     atomized version); this means that the context of a non-atomic
   415     statement becomes is included in the hypothesis, avoiding the
   416     slightly cumbersome show "PROP ?case" form;
   417   - 'induct' may now use elim-style induction rules without chaining
   418     facts, using ``missing'' premises from the goal state; this allows
   419     rules stemming from inductive sets to be applied in unstructured
   420     scripts, while still benefitting from proper handling of non-atomic
   421     statements; NB: major inductive premises need to be put first, all
   422     the rest of the goal is passed through the induction;
   423   - 'induct' proper support for mutual induction involving non-atomic
   424     rule statements (uses the new concept of simultaneous goals, see
   425     below);
   426   - append all possible rule selections, but only use the first
   427     success (no backtracking);
   428   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   429   - undeclared rule case names default to numbers 1, 2, 3, ...;
   430   - added 'print_induct_rules' (covered by help item in recent Proof
   431     General versions);
   432   - moved induct/cases attributes to Pure, methods to Provers;
   433   - generic method setup instantiated for FOL and HOL;
   434 
   435 * Pure: support multiple simultaneous goal statements, for example
   436 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   437 meta-level mechanism, this acts as if several individual goals had
   438 been stated separately; in particular common proof methods need to be
   439 repeated in order to cover all claims; note that a single elimination
   440 step is *not* sufficient to establish the two conjunctions, so this
   441 fails:
   442 
   443   assume "A & B" then have A and B ..   (*".." fails*)
   444 
   445 better use "obtain" in situations as above; alternative refer to
   446 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   447 
   448 * Pure: proper integration with ``locales''; unlike the original
   449 version by Florian Kammüller, Isar locales package high-level proof
   450 contexts rather than raw logical ones (e.g. we admit to include
   451 attributes everywhere); operations on locales include merge and
   452 rename; support for implicit arguments (``structures''); simultaneous
   453 type-inference over imports and text; see also HOL/ex/Locales.thy for
   454 some examples;
   455 
   456 * Pure: the following commands have been ``localized'', supporting a
   457 target locale specification "(in name)": 'lemma', 'theorem',
   458 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   459 stored both within the locale and at the theory level (exported and
   460 qualified by the locale name);
   461 
   462 * Pure: theory goals may now be specified in ``long'' form, with
   463 ad-hoc contexts consisting of arbitrary locale elements. for example
   464 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   465 definitions may be given, too); the result is a meta-level rule with
   466 the context elements being discharged in the obvious way;
   467 
   468 * Pure: new proof command 'using' allows to augment currently used
   469 facts after a goal statement ('using' is syntactically analogous to
   470 'apply', but acts on the goal's facts only); this allows chained facts
   471 to be separated into parts given before and after a claim, as in
   472 ``from a and b have C using d and e <proof>'';
   473 
   474 * Pure: renamed "antecedent" case to "rule_context";
   475 
   476 * Pure: new 'judgment' command records explicit information about the
   477 object-logic embedding (used by several tools internally); no longer
   478 use hard-wired "Trueprop";
   479 
   480 * Pure: added 'corollary' command;
   481 
   482 * Pure: fixed 'token_translation' command;
   483 
   484 * Pure: removed obsolete 'exported' attribute;
   485 
   486 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   487 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   488 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   489 
   490 * Pure: method 'atomize' presents local goal premises as object-level
   491 statements (atomic meta-level propositions); setup controlled via
   492 rewrite rules declarations of 'atomize' attribute; example
   493 application: 'induct' method with proper rule statements in improper
   494 proof *scripts*;
   495 
   496 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   497 now consider the syntactic context of assumptions, giving a better
   498 chance to get type-inference of the arguments right (this is
   499 especially important for locales);
   500 
   501 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   502 mode;
   503 
   504 * Pure/obtain: the formal conclusion "thesis", being marked as
   505 ``internal'', may no longer be reference directly in the text;
   506 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   507 situations;
   508 
   509 * Pure: generic 'sym' attribute which declares a rule both as pure
   510 'elim?' and for the 'symmetric' operation;
   511 
   512 * Pure: marginal comments ``--'' may now occur just anywhere in the
   513 text; the fixed correlation with particular command syntax has been
   514 discontinued;
   515 
   516 * Pure: new method 'rules' is particularly well-suited for proof
   517 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   518 but often produces more compact proof terms with less detours;
   519 
   520 * Pure/Provers/classical: simplified integration with pure rule
   521 attributes and methods; the classical "intro?/elim?/dest?"
   522 declarations coincide with the pure ones; the "rule" method no longer
   523 includes classically swapped intros; "intro" and "elim" methods no
   524 longer pick rules from the context; also got rid of ML declarations
   525 AddXIs/AddXEs/AddXDs; all of this has some potential for
   526 INCOMPATIBILITY;
   527 
   528 * Provers/classical: attribute 'swapped' produces classical inversions
   529 of introduction rules;
   530 
   531 * Provers/simplifier: 'simplified' attribute may refer to explicit
   532 rules instead of full simplifier context; 'iff' attribute handles
   533 conditional rules;
   534 
   535 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   536 
   537 * HOL: 'recdef' now fails on unfinished automated proofs, use
   538 "(permissive)" option to recover old behavior;
   539 
   540 * HOL: 'inductive' no longer features separate (collective) attributes
   541 for 'intros' (was found too confusing);
   542 
   543 * HOL: properly declared induction rules less_induct and
   544 wf_induct_rule;
   545 
   546 
   547 *** HOL ***
   548 
   549 * HOL: moved over to sane numeral syntax; the new policy is as
   550 follows:
   551 
   552   - 0 and 1 are polymorphic constants, which are defined on any
   553   numeric type (nat, int, real etc.);
   554 
   555   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   556   binary representation internally;
   557 
   558   - type nat has special constructor Suc, and generally prefers Suc 0
   559   over 1::nat and Suc (Suc 0) over 2::nat;
   560 
   561 This change may cause significant problems of INCOMPATIBILITY; here
   562 are some hints on converting existing sources:
   563 
   564   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   565   entities, so expressions involving "-" (unary or binary minus) need
   566   to be spaced properly;
   567 
   568   - existing occurrences of "1" may need to be constraint "1::nat" or
   569   even replaced by Suc 0; similar for old "2";
   570 
   571   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   572 
   573   - remove all special provisions on numerals in proofs;
   574 
   575 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   576 representation (depends on bin_arith_simps in the default context);
   577 
   578 * HOL: symbolic syntax for x^2 (numeral 2);
   579 
   580 * HOL: the class of all HOL types is now called "type" rather than
   581 "term"; INCOMPATIBILITY, need to adapt references to this type class
   582 in axclass/classes, instance/arities, and (usually rare) occurrences
   583 in typings (of consts etc.); internally the class is called
   584 "HOL.type", ML programs should refer to HOLogic.typeS;
   585 
   586 * HOL/record package improvements:
   587   - new derived operations "fields" to build a partial record section,
   588     "extend" to promote a fixed record to a record scheme, and
   589     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   590     declared as simp by default;
   591   - shared operations ("more", "fields", etc.) now need to be always
   592     qualified) --- potential INCOMPATIBILITY;
   593   - removed "make_scheme" operations (use "make" with "extend") --
   594     INCOMPATIBILITY;
   595   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   596   - provides cases/induct rules for use with corresponding Isar
   597     methods (for concrete records, record schemes, concrete more
   598     parts, and schematic more parts -- in that order);
   599   - internal definitions directly based on a light-weight abstract
   600     theory of product types over typedef rather than datatype;
   601 
   602 * HOL: generic code generator for generating executable ML code from
   603 specifications; specific support for HOL constructs such as inductive
   604 datatypes and sets, as well as recursive functions; can be invoked
   605 via 'generate_code' theory section;
   606 
   607 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   608 
   609 * HOL: consolidated and renamed several theories.  In particular:
   610 	Ord.thy has been absorbed into HOL.thy
   611 	String.thy has been absorbed into List.thy
   612  
   613 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   614 (beware of argument permutation!);
   615 
   616 * HOL: linorder_less_split superseded by linorder_cases;
   617 
   618 * HOL/List: "nodups" renamed to "distinct";
   619 
   620 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   621 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   622   - Ex_def has changed, now need to use some_eq_ex
   623 
   624 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   625 in this (rare) case use:
   626 
   627   delSWrapper "split_all_tac"
   628   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   629 
   630 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   631 MAY FAIL;
   632 
   633 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   634 Isabelle's type classes, ^ on functions and relations has too general
   635 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   636 necessary to attach explicit type constraints;
   637 
   638 * HOL/Relation: the prefix name of the infix "O" has been changed from
   639 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   640 renamed accordingly (eg "compI" -> "rel_compI").
   641 
   642 * HOL: syntax translations now work properly with numerals and records
   643 expressions;
   644 
   645 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   646 of "lam" -- INCOMPATIBILITY;
   647 
   648 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   649 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   650 renamed "Product_Type.unit";
   651 
   652 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   653 
   654 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   655 the "cases" method);
   656 
   657 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   658 Florian Kammüller);
   659 
   660 * HOL/IMP: updated and converted to new-style theory format; several
   661 parts turned into readable document, with proper Isar proof texts and
   662 some explanations (by Gerwin Klein);
   663 
   664 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   665 
   666 * HOL-Hyperreal is now a logic image;
   667 
   668 
   669 *** HOLCF ***
   670 
   671 * Isar: consts/constdefs supports mixfix syntax for continuous
   672 operations;
   673 
   674 * Isar: domain package adapted to new-style theory format, e.g. see
   675 HOLCF/ex/Dnat.thy;
   676 
   677 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   678 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   679 lift.induct_tac, always use UU instead of Undef;
   680 
   681 * HOLCF/IMP: updated and converted to new-style theory;
   682 
   683 
   684 *** ZF ***
   685 
   686 * Isar: proper integration of logic-specific tools and packages,
   687 including theory commands '(co)inductive', '(co)datatype',
   688 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   689 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   690 
   691 * theory Main no longer includes AC; for the Axiom of Choice, base
   692 your theory on Main_ZFC;
   693 
   694 * the integer library now covers quotients and remainders, with many
   695 laws relating division to addition, multiplication, etc.;
   696 
   697 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   698 typeless version of the formalism;
   699 
   700 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   701 format;
   702 
   703 * ZF/Induct: new directory for examples of inductive definitions,
   704 including theory Multiset for multiset orderings; converted to
   705 new-style theory format;
   706 
   707 * ZF: many new theorems about lists, ordinals, etc.;
   708 
   709 
   710 *** General ***
   711 
   712 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   713 variable proof controls level of detail: 0 = no proofs (only oracle
   714 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   715 also ref manual for further ML interfaces;
   716 
   717 * Pure/axclass: removed obsolete ML interface
   718 goal_subclass/goal_arity;
   719 
   720 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   721 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   722 separate tokens, so expressions involving minus need to be spaced
   723 properly;
   724 
   725 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   726 rather than "infixl" or "infixr";
   727 
   728 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   729 sort constraint specifications in type inference; e.g. "x::_::foo"
   730 ensures that the type of "x" is of sort "foo" (but not necessarily a
   731 type variable);
   732 
   733 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   734 control output of nested => (types); the default behavior is
   735 "type_brackets";
   736 
   737 * Pure/syntax: builtin parse translation for "_constify" turns valued
   738 tokens into AST constants;
   739 
   740 * Pure/syntax: prefer later declarations of translations and print
   741 translation functions; potential INCOMPATIBILITY: need to reverse
   742 multiple declarations for same syntax element constant;
   743 
   744 * Pure/show_hyps reset by default (in accordance to existing Isar
   745 practice);
   746 
   747 * Provers/classical: renamed addaltern to addafter, addSaltern to
   748 addSafter;
   749 
   750 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   751 as well;
   752 
   753 * system: tested support for MacOS X; should be able to get Isabelle +
   754 Proof General to work in a plain Terminal after installing Poly/ML
   755 (e.g. from the Isabelle distribution area) and GNU bash alone
   756 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   757 support requires further installations, e.g. from
   758 http://fink.sourceforge.net/);
   759 
   760 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   761 
   762 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   763 of 40 MB), cf. ML_OPTIONS;
   764 
   765 * system: Proof General keywords specification is now part of the
   766 Isabelle distribution (see etc/isar-keywords.el);
   767 
   768 * system: support for persistent Proof General sessions (refrain from
   769 outdating all loaded theories on startup); user may create writable
   770 logic images like this: ``isabelle -q HOL Test'';
   771 
   772 * system: smart selection of Isabelle process versus Isabelle
   773 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   774 run both "isabelle" and "Isabelle" even if file names are badly
   775 damaged (executable inspects the case of the first letter of its own
   776 name); added separate "isabelle-process" and "isabelle-interface";
   777 
   778 * system: refrain from any attempt at filtering input streams; no
   779 longer support ``8bit'' encoding of old isabelle font, instead proper
   780 iso-latin characters may now be used; the related isatools
   781 "symbolinput" and "nonascii" have disappeared as well;
   782 
   783 * system: removed old "xterm" interface (the print modes "xterm" and
   784 "xterm_color" are still available for direct use in a suitable
   785 terminal);
   786 
   787 
   788 
   789 New in Isabelle99-2 (February 2001)
   790 -----------------------------------
   791 
   792 *** Overview of INCOMPATIBILITIES ***
   793 
   794 * HOL: please note that theories in the Library and elsewhere often use the
   795 new-style (Isar) format; to refer to their theorems in an ML script you must
   796 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   797 
   798 * HOL: inductive package no longer splits induction rule aggressively,
   799 but only as far as specified by the introductions given; the old
   800 format may be recovered via ML function complete_split_rule or attribute
   801 'split_rule (complete)';
   802 
   803 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   804 gfp_Tarski to gfp_unfold;
   805 
   806 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   807 
   808 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   809 relation); infix "^^" has been renamed "``"; infix "``" has been
   810 renamed "`"; "univalent" has been renamed "single_valued";
   811 
   812 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   813 operation;
   814 
   815 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   816 
   817 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   818 
   819 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   820 consequence, it is no longer monotonic wrt. the local goal context
   821 (which is now passed through the inductive cases);
   822 
   823 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   824 \<gg> to \<ggreater>;
   825 
   826 
   827 *** Document preparation ***
   828 
   829 * \isabellestyle{NAME} selects version of Isabelle output (currently
   830 available: are "it" for near math-mode best-style output, "sl" for
   831 slanted text style, and "tt" for plain type-writer; if no
   832 \isabellestyle command is given, output is according to slanted
   833 type-writer);
   834 
   835 * support sub/super scripts (for single symbols only), input syntax is
   836 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   837 
   838 * some more standard symbols; see Appendix A of the system manual for
   839 the complete list of symbols defined in isabellesym.sty;
   840 
   841 * improved isabelle style files; more abstract symbol implementation
   842 (should now use \isamath{...} and \isatext{...} in custom symbol
   843 definitions);
   844 
   845 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   846 state; Note that presentation of goal states does not conform to
   847 actual human-readable proof documents.  Please do not include goal
   848 states into document output unless you really know what you are doing!
   849 
   850 * proper indentation of antiquoted output with proportional LaTeX
   851 fonts;
   852 
   853 * no_document ML operator temporarily disables LaTeX document
   854 generation;
   855 
   856 * isatool unsymbolize tunes sources for plain ASCII communication;
   857 
   858 
   859 *** Isar ***
   860 
   861 * Pure: Isar now suffers initial goal statements to contain unbound
   862 schematic variables (this does not conform to actual readable proof
   863 documents, due to unpredictable outcome and non-compositional proof
   864 checking); users who know what they are doing may use schematic goals
   865 for Prolog-style synthesis of proven results;
   866 
   867 * Pure: assumption method (an implicit finishing) now handles actual
   868 rules as well;
   869 
   870 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   871 initial goal, declare "that" only as Pure intro (only for single
   872 steps); the "that" rule assumption may now be involved in implicit
   873 finishing, thus ".." becomes a feasible for trivial obtains;
   874 
   875 * Pure: default proof step now includes 'intro_classes'; thus trivial
   876 instance proofs may be performed by "..";
   877 
   878 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   879 statements as well;
   880 
   881 * Pure: more robust selection of calculational rules;
   882 
   883 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   884 rule (as well as the assumption rule);
   885 
   886 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   887 lemmas, using the graph browser tool;
   888 
   889 * Pure: predict failure of "show" in interactive mode;
   890 
   891 * Pure: 'thms_containing' now takes actual terms as arguments;
   892 
   893 * HOL: improved method 'induct' --- now handles non-atomic goals
   894 (potential INCOMPATIBILITY); tuned error handling;
   895 
   896 * HOL: cases and induct rules now provide explicit hints about the
   897 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   898 any remaining facts are inserted into the goal verbatim;
   899 
   900 * HOL: local contexts (aka cases) may now contain term bindings as
   901 well; the 'cases' and 'induct' methods new provide a ?case binding for
   902 the result to be shown in each case;
   903 
   904 * HOL: added 'recdef_tc' command;
   905 
   906 * isatool convert assists in eliminating legacy ML scripts;
   907 
   908 
   909 *** HOL ***
   910 
   911 * HOL/Library: a collection of generic theories to be used together
   912 with main HOL; the theory loader path already includes this directory
   913 by default; the following existing theories have been moved here:
   914 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   915 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   916 
   917 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   918 modelling and verification task performed in Isabelle/HOL +
   919 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   920 
   921 * HOL/Algebra: special summation operator SUM no longer exists, it has
   922 been replaced by setsum; infix 'assoc' now has priority 50 (like
   923 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   924 'domain', this makes the theory consistent with mathematical
   925 literature;
   926 
   927 * HOL basics: added overloaded operations "inverse" and "divide"
   928 (infix "/"), syntax for generic "abs" operation, generic summation
   929 operator \<Sum>;
   930 
   931 * HOL/typedef: simplified package, provide more useful rules (see also
   932 HOL/subset.thy);
   933 
   934 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   935 now expressed as a proper nested rule (old-style tactic scripts may
   936 require atomize_strip_tac to cope with non-atomic premises);
   937 
   938 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   939 to "split_conv" (old name still available for compatibility);
   940 
   941 * HOL: improved concrete syntax for strings (e.g. allows translation
   942 rules with string literals);
   943 
   944 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   945  and Fleuriot's mechanization of analysis, including the transcendental
   946  functions for the reals;
   947 
   948 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   949 
   950 
   951 *** CTT ***
   952 
   953 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   954 "lam" is displayed as TWO lambda-symbols
   955 
   956 * CTT: theory Main now available, containing everything (that is, Bool
   957 and Arith);
   958 
   959 
   960 *** General ***
   961 
   962 * Pure: the Simplifier has been implemented properly as a derived rule
   963 outside of the actual kernel (at last!); the overall performance
   964 penalty in practical applications is about 50%, while reliability of
   965 the Isabelle inference kernel has been greatly improved;
   966 
   967 * print modes "brackets" and "no_brackets" control output of nested =>
   968 (types) and ==> (props); the default behaviour is "brackets";
   969 
   970 * Provers: fast_tac (and friends) now handle actual object-logic rules
   971 as assumptions as well;
   972 
   973 * system: support Poly/ML 4.0;
   974 
   975 * system: isatool install handles KDE version 1 or 2;
   976 
   977 
   978 
   979 New in Isabelle99-1 (October 2000)
   980 ----------------------------------
   981 
   982 *** Overview of INCOMPATIBILITIES ***
   983 
   984 * HOL: simplification of natural numbers is much changed; to partly
   985 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   986 issue the following ML commands:
   987 
   988   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   989   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   990 
   991 * HOL: simplification no longer dives into case-expressions; this is
   992 controlled by "t.weak_case_cong" for each datatype t;
   993 
   994 * HOL: nat_less_induct renamed to less_induct;
   995 
   996 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   997 fixsome to patch .thy and .ML sources automatically;
   998 
   999   select_equality  -> some_equality
  1000   select_eq_Ex     -> some_eq_ex
  1001   selectI2EX       -> someI2_ex
  1002   selectI2         -> someI2
  1003   selectI          -> someI
  1004   select1_equality -> some1_equality
  1005   Eps_sym_eq       -> some_sym_eq_trivial
  1006   Eps_eq           -> some_eq_trivial
  1007 
  1008 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1009 
  1010 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1011 instead);
  1012 
  1013 * HOL: the recursion equations generated by 'recdef' are now called
  1014 f.simps instead of f.rules;
  1015 
  1016 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1017 
  1018 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1019 sometimes be needed;
  1020 
  1021 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1022 
  1023 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1024 
  1025 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1026 product is now "<*>" instead of "Times"; the lexicographic product is
  1027 now "<*lex*>" instead of "**";
  1028 
  1029 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1030 of main HOL, but was unused); better use HOL's datatype package;
  1031 
  1032 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1033 the old syntax may be recovered as follows:
  1034 
  1035   syntax (symbols)
  1036     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1037       (infixl "\\<oplus>" 100)
  1038 
  1039 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1040 
  1041 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1042 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1043 internally;
  1044 
  1045 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1046 changed from A/r to A//r;
  1047 
  1048 * ZF: new treatment of arithmetic (nat & int) may break some old
  1049 proofs;
  1050 
  1051 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1052 rulify -> rule_format, elimify -> elim_format, ...);
  1053 
  1054 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1055 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1056 should have to change intro!! to intro? only); replaced "delrule" by
  1057 "rule del";
  1058 
  1059 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1060 
  1061 * Provers: strengthened force_tac by using new first_best_tac;
  1062 
  1063 * LaTeX document preparation: several changes of isabelle.sty (see
  1064 lib/texinputs);
  1065 
  1066 
  1067 *** Document preparation ***
  1068 
  1069 * formal comments (text blocks etc.) in new-style theories may now
  1070 contain antiquotations of thm/prop/term/typ/text to be presented
  1071 according to latex print mode; concrete syntax is like this:
  1072 @{term[show_types] "f(x) = a + x"};
  1073 
  1074 * isatool mkdir provides easy setup of Isabelle session directories,
  1075 including proper document sources;
  1076 
  1077 * generated LaTeX sources are now deleted after successful run
  1078 (isatool document -c); may retain a copy somewhere else via -D option
  1079 of isatool usedir;
  1080 
  1081 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1082 style files, achieving self-contained LaTeX sources and simplifying
  1083 LaTeX debugging;
  1084 
  1085 * old-style theories now produce (crude) LaTeX output as well;
  1086 
  1087 * browser info session directories are now self-contained (may be put
  1088 on WWW server seperately); improved graphs of nested sessions; removed
  1089 graph for 'all sessions';
  1090 
  1091 * several improvements in isabelle style files; \isabellestyle{it}
  1092 produces fake math mode output; \isamarkupheader is now \section by
  1093 default; see lib/texinputs/isabelle.sty etc.;
  1094 
  1095 
  1096 *** Isar ***
  1097 
  1098 * Isar/Pure: local results and corresponding term bindings are now
  1099 subject to Hindley-Milner polymorphism (similar to ML); this
  1100 accommodates incremental type-inference very nicely;
  1101 
  1102 * Isar/Pure: new derived language element 'obtain' supports
  1103 generalized existence reasoning;
  1104 
  1105 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1106 support accumulation of results, without applying any rules yet;
  1107 useful to collect intermediate results without explicit name
  1108 references, and for use with transitivity rules with more than 2
  1109 premises;
  1110 
  1111 * Isar/Pure: scalable support for case-analysis type proofs: new
  1112 'case' language element refers to local contexts symbolically, as
  1113 produced by certain proof methods; internally, case names are attached
  1114 to theorems as "tags";
  1115 
  1116 * Isar/Pure: theory command 'hide' removes declarations from
  1117 class/type/const name spaces;
  1118 
  1119 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1120 indicate potential overloading;
  1121 
  1122 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1123 
  1124 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1125 "{a,b,c}" instead of {a,b,c};
  1126 
  1127 * Isar/Pure now provides its own version of intro/elim/dest
  1128 attributes; useful for building new logics, but beware of confusion
  1129 with the version in Provers/classical;
  1130 
  1131 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1132 case name 'antecedent';
  1133 
  1134 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1135 to the current context is now done automatically);
  1136 
  1137 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1138 for definining proof methods in ML;
  1139 
  1140 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1141 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1142 most cases, one should have to change intro!! to intro? only);
  1143 replaced "delrule" by "rule del";
  1144 
  1145 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1146 'symmetric' attribute (the latter supercedes [RS sym]);
  1147 
  1148 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1149 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1150 well (including splits);
  1151 
  1152 * Isar/Provers: Simplifier and Classical methods now support all kind
  1153 of modifiers used in the past, including 'cong', 'iff', etc.
  1154 
  1155 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1156 of Simplifier and Classical reasoner);
  1157 
  1158 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1159 now support named cases; major packages (inductive, datatype, primrec,
  1160 recdef) support case names and properly name parameters;
  1161 
  1162 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1163 monotonicity conditions are extracted to be proven at end of
  1164 calculations;
  1165 
  1166 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1167 method anyway;
  1168 
  1169 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1170 split_if split_if_asm; datatype package provides theorems foo.splits =
  1171 foo.split foo.split_asm for each datatype;
  1172 
  1173 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1174 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1175 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1176 use "(cases (simplified))" method in proper proof texts);
  1177 
  1178 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1179 
  1180 * Isar: names of theorems etc. may be natural numbers as well;
  1181 
  1182 * Isar: 'pr' command: optional arguments for goals_limit and
  1183 ProofContext.prems_limit; no longer prints theory contexts, but only
  1184 proof states;
  1185 
  1186 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1187 additional print modes to be specified; e.g. "pr(latex)" will print
  1188 proof state according to the Isabelle LaTeX style;
  1189 
  1190 * Isar: improved support for emulating tactic scripts, including proof
  1191 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1192 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1193 (for HOL datatypes);
  1194 
  1195 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1196 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1197 'proof method scripts' have to be in depth-first order;
  1198 
  1199 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1200 
  1201 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1202 should instead use individual commands for printing items
  1203 (print_commands, print_methods etc.);
  1204 
  1205 * Isar: added 'nothing' --- the empty list of theorems;
  1206 
  1207 
  1208 *** HOL ***
  1209 
  1210 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1211 corresponding virtual machine and a specification of its bytecode
  1212 verifier and a lightweight bytecode verifier, including proofs of
  1213 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1214 Cornelia Pusch (see also the homepage of project Bali at
  1215 http://isabelle.in.tum.de/Bali/);
  1216 
  1217 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1218 Clemens Ballarin;
  1219 
  1220 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1221 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1222 Rasmussen;
  1223 
  1224 * HOL/Lattice: fundamental concepts of lattice theory and order
  1225 structures, including duals, properties of bounds versus algebraic
  1226 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1227 Theorem for complete lattices etc.; may also serve as a demonstration
  1228 for abstract algebraic reasoning using axiomatic type classes, and
  1229 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1230 
  1231 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1232 von Oheimb;
  1233 
  1234 * HOL/IMPP: extension of IMP with local variables and mutually
  1235 recursive procedures, by David von Oheimb;
  1236 
  1237 * HOL/Lambda: converted into new-style theory and document;
  1238 
  1239 * HOL/ex/Multiquote: example of multiple nested quotations and
  1240 anti-quotations -- basically a generalized version of de-Bruijn
  1241 representation; very useful in avoiding lifting of operations;
  1242 
  1243 * HOL/record: added general record equality rule to simpset; fixed
  1244 select-update simplification procedure to handle extended records as
  1245 well; admit "r" as field name;
  1246 
  1247 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1248 other numeric types and also as the identity of groups, rings, etc.;
  1249 
  1250 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1251 Types nat and int belong to this axclass;
  1252 
  1253 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1254    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1255    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1256   two terms #m*u and #n*u are replaced by #(m+n)*u
  1257     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1258   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1259     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1260 
  1261 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1262 powerful prover for predicate logic but knows nothing of clasets; see
  1263 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1264 
  1265 * HOL: new version of "case_tac" subsumes both boolean case split and
  1266 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1267 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1268 
  1269 * HOL: simplification no longer dives into case-expressions: only the
  1270 selector expression is simplified, but not the remaining arms; to
  1271 enable full simplification of case-expressions for datatype t, you may
  1272 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1273 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1274 
  1275 * HOL/recdef: the recursion equations generated by 'recdef' for
  1276 function 'f' are now called f.simps instead of f.rules; if all
  1277 termination conditions are proved automatically, these simplification
  1278 rules are added to the simpset, as in primrec; rules may be named
  1279 individually as well, resulting in a separate list of theorems for
  1280 each equation;
  1281 
  1282 * HOL/While is a new theory that provides a while-combinator. It
  1283 permits the definition of tail-recursive functions without the
  1284 provision of a termination measure. The latter is necessary once the
  1285 invariant proof rule for while is applied.
  1286 
  1287 * HOL: new (overloaded) notation for the set of elements below/above
  1288 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1289 
  1290 * HOL: theorems impI, allI, ballI bound as "strip";
  1291 
  1292 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1293 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1294 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1295 
  1296 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1297 
  1298 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1299 main HOL, but was unused);
  1300 
  1301 * HOL: fewer consts declared as global (e.g. have to refer to
  1302 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1303 
  1304 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1305 in case of overlap with user translations (e.g. judgements over
  1306 tuples); (note that the underlying logical represenation is still
  1307 bogus);
  1308 
  1309 
  1310 *** ZF ***
  1311 
  1312 * ZF: simplification automatically cancels common terms in arithmetic
  1313 expressions over nat and int;
  1314 
  1315 * ZF: new treatment of nat to minimize type-checking: all operators
  1316 coerce their operands to a natural number using the function natify,
  1317 making the algebraic laws unconditional;
  1318 
  1319 * ZF: as above, for int: operators coerce their operands to an integer
  1320 using the function intify;
  1321 
  1322 * ZF: the integer library now contains many of the usual laws for the
  1323 orderings, including $<=, and monotonicity laws for $+ and $*;
  1324 
  1325 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1326 simplification;
  1327 
  1328 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1329 to the simplifier and classical reasoner simultaneously;
  1330 
  1331 
  1332 *** General ***
  1333 
  1334 * Provers: blast_tac now handles actual object-logic rules as
  1335 assumptions; note that auto_tac uses blast_tac internally as well;
  1336 
  1337 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1338 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1339 
  1340 * Provers: delrules now handles destruct rules as well (no longer need
  1341 explicit make_elim);
  1342 
  1343 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1344   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1345 use instead the strong form,
  1346   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1347 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1348 from destruct-rules;
  1349 
  1350 * Provers: Simplifier.easy_setup provides a fast path to basic
  1351 Simplifier setup for new object-logics;
  1352 
  1353 * Pure: AST translation rules no longer require constant head on LHS;
  1354 
  1355 * Pure: improved name spaces: ambiguous output is qualified; support
  1356 for hiding of names;
  1357 
  1358 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1359 XSYMBOL_HOME; no longer need to do manual configuration in most
  1360 situations;
  1361 
  1362 * system: compression of ML heaps images may now be controlled via -c
  1363 option of isabelle and isatool usedir (currently only observed by
  1364 Poly/ML);
  1365 
  1366 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1367 useful for remote X11);
  1368 
  1369 * system: provide TAGS file for Isabelle sources;
  1370 
  1371 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1372 order;
  1373 
  1374 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1375 timing flag supersedes proof_timing and Toplevel.trace;
  1376 
  1377 * ML: new combinators |>> and |>>> for incremental transformations
  1378 with secondary results (e.g. certain theory extensions):
  1379 
  1380 * ML: PureThy.add_defs gets additional argument to indicate potential
  1381 overloading (usually false);
  1382 
  1383 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1384 results;
  1385 
  1386 
  1387 
  1388 New in Isabelle99 (October 1999)
  1389 --------------------------------
  1390 
  1391 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1392 
  1393 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1394 are no longer simplified.  (This allows the simplifier to unfold recursive
  1395 functional programs.)  To restore the old behaviour, declare
  1396 
  1397     Delcongs [if_weak_cong];
  1398 
  1399 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1400 complement;
  1401 
  1402 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1403 
  1404 * HOL/datatype: mutual_induct_tac no longer exists --
  1405   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1406 
  1407 * HOL/typedef: fixed type inference for representing set; type
  1408 arguments now have to occur explicitly on the rhs as type constraints;
  1409 
  1410 * ZF: The con_defs part of an inductive definition may no longer refer
  1411 to constants declared in the same theory;
  1412 
  1413 * HOL, ZF: the function mk_cases, generated by the inductive
  1414 definition package, has lost an argument.  To simplify its result, it
  1415 uses the default simpset instead of a supplied list of theorems.
  1416 
  1417 * HOL/List: the constructors of type list are now Nil and Cons;
  1418 
  1419 * Simplifier: the type of the infix ML functions
  1420         setSSolver addSSolver setSolver addSolver
  1421 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1422 for packaging solvers. A solver is created via
  1423         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1424 where the string argument is only a comment.
  1425 
  1426 
  1427 *** Proof tools ***
  1428 
  1429 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1430 decision procedure for linear arithmetic. Currently it is used for
  1431 types `nat', `int', and `real' in HOL (see below); it can, should and
  1432 will be instantiated for other types and logics as well.
  1433 
  1434 * The simplifier now accepts rewrite rules with flexible heads, eg
  1435      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1436   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1437   matching.
  1438 
  1439 
  1440 *** General ***
  1441 
  1442 * New Isabelle/Isar subsystem provides an alternative to traditional
  1443 tactical theorem proving; together with the ProofGeneral/isar user
  1444 interface it offers an interactive environment for developing human
  1445 readable proof documents (Isar == Intelligible semi-automated
  1446 reasoning); for further information see isatool doc isar-ref,
  1447 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1448 
  1449 * improved and simplified presentation of theories: better HTML markup
  1450 (including colors), graph views in several sizes; isatool usedir now
  1451 provides a proper interface for user theories (via -P option); actual
  1452 document preparation based on (PDF)LaTeX is available as well (for
  1453 new-style theories only); see isatool doc system for more information;
  1454 
  1455 * native support for Proof General, both for classic Isabelle and
  1456 Isabelle/Isar;
  1457 
  1458 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1459 using the graph browser tool;
  1460 
  1461 * Isabelle manuals now also available as PDF;
  1462 
  1463 * theory loader rewritten from scratch (may not be fully
  1464 bug-compatible); old loadpath variable has been replaced by show_path,
  1465 add_path, del_path, reset_path functions; new operations such as
  1466 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1467 isatool doc ref);
  1468 
  1469 * improved isatool install: option -k creates KDE application icon,
  1470 option -p DIR installs standalone binaries;
  1471 
  1472 * added ML_PLATFORM setting (useful for cross-platform installations);
  1473 more robust handling of platform specific ML images for SML/NJ;
  1474 
  1475 * the settings environment is now statically scoped, i.e. it is never
  1476 created again in sub-processes invoked from isabelle, isatool, or
  1477 Isabelle;
  1478 
  1479 * path element specification '~~' refers to '$ISABELLE_HOME';
  1480 
  1481 * in locales, the "assumes" and "defines" parts may be omitted if
  1482 empty;
  1483 
  1484 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1485 long arrows);
  1486 
  1487 * new print_mode "HTML";
  1488 
  1489 * new flag show_tags controls display of tags of theorems (which are
  1490 basically just comments that may be attached by some tools);
  1491 
  1492 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1493 mode and goal output format:
  1494 
  1495 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1496 244c244
  1497 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1498 ---
  1499 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1500 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1501 181c181
  1502 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1503 ---
  1504 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1505 
  1506 * function bind_thms stores lists of theorems (cf. bind_thm);
  1507 
  1508 * new shorthand tactics ftac, eatac, datac, fatac;
  1509 
  1510 * qed (and friends) now accept "" as result name; in that case the
  1511 theorem is not stored, but proper checks and presentation of the
  1512 result still apply;
  1513 
  1514 * theorem database now also indexes constants "Trueprop", "all",
  1515 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1516 
  1517 
  1518 *** HOL ***
  1519 
  1520 ** HOL arithmetic **
  1521 
  1522 * There are now decision procedures for linear arithmetic over nat and
  1523 int:
  1524 
  1525 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1526 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1527 are treated as atomic; subformulae not involving type `nat' or `int'
  1528 are ignored; quantified subformulae are ignored unless they are
  1529 positive universal or negative existential. The tactic has to be
  1530 invoked by hand and can be a little bit slow. In particular, the
  1531 running time is exponential in the number of occurrences of `min' and
  1532 `max', and `-' on `nat'.
  1533 
  1534 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1535 (negated) (in)equalities among the premises and the conclusion into
  1536 account (i.e. no compound formulae) and does not know about `min' and
  1537 `max', and `-' on `nat'. It is fast and is used automatically by the
  1538 simplifier.
  1539 
  1540 NB: At the moment, these decision procedures do not cope with mixed
  1541 nat/int formulae where the two parts interact, such as `m < n ==>
  1542 int(m) < int(n)'.
  1543 
  1544 * HOL/Numeral provides a generic theory of numerals (encoded
  1545 efficiently as bit strings); setup for types nat/int/real is in place;
  1546 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1547 int, existing theories and proof scripts may require a few additional
  1548 type constraints;
  1549 
  1550 * integer division and remainder can now be performed on constant
  1551 arguments;
  1552 
  1553 * many properties of integer multiplication, division and remainder
  1554 are now available;
  1555 
  1556 * An interface to the Stanford Validity Checker (SVC) is available through the
  1557 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1558 are proved automatically.  SVC must be installed separately, and its results
  1559 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1560 invocation of the underlying oracle).  For SVC see
  1561   http://verify.stanford.edu/SVC
  1562 
  1563 * IsaMakefile: the HOL-Real target now builds an actual image;
  1564 
  1565 
  1566 ** HOL misc **
  1567 
  1568 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1569 (in Isabelle/Isar) -- by Gertrud Bauer;
  1570 
  1571 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1572 analysis for assembly languages with subtypes;
  1573 
  1574 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1575 -- avoids syntactic ambiguities and treats state, transition, and
  1576 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1577 changed syntax and (many) tactics;
  1578 
  1579 * HOL/inductive: Now also handles more general introduction rules such
  1580   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1581   theorems are now maintained within the theory (maintained via the
  1582   "mono" attribute);
  1583 
  1584 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1585   (using function types) such as
  1586 
  1587   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1588 
  1589 * HOL/record: record_simproc (part of the default simpset) takes care
  1590 of selectors applied to updated records; record_split_tac is no longer
  1591 part of the default claset; update_defs may now be removed from the
  1592 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1593 
  1594   claset_ref () := claset() addSWrapper record_split_wrapper;
  1595   Delsimprocs [record_simproc]
  1596 
  1597 * HOL/typedef: fixed type inference for representing set; type
  1598 arguments now have to occur explicitly on the rhs as type constraints;
  1599 
  1600 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1601 names rather than an ML expression;
  1602 
  1603 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1604 supplied later.  Program schemes can be defined, such as
  1605     "While B C s = (if B s then While B C (C s) else s)"
  1606 where the well-founded relation can be chosen after B and C have been given.
  1607 
  1608 * HOL/List: the constructors of type list are now Nil and Cons;
  1609 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1610 course, ML tools referring to List.list.op # etc. have to be adapted;
  1611 
  1612 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1613 disabled by default; run isabelle with option -m HOL to get back to
  1614 the original Gordon/HOL-style output;
  1615 
  1616 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1617 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1618 
  1619 * HOL basic syntax simplified (more orthogonal): all variants of
  1620 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1621 Eps operator is provided as well: "SOME x. P[x]";
  1622 
  1623 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1624 
  1625 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1626 thus available for user theories;
  1627 
  1628 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1629 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1630 time;
  1631 
  1632 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1633 several times and then mp;
  1634 
  1635 
  1636 *** LK ***
  1637 
  1638 * the notation <<...>> is now available as a notation for sequences of
  1639 formulas;
  1640 
  1641 * the simplifier is now installed
  1642 
  1643 * the axiom system has been generalized (thanks to Soren Heilmann)
  1644 
  1645 * the classical reasoner now has a default rule database
  1646 
  1647 
  1648 *** ZF ***
  1649 
  1650 * new primrec section allows primitive recursive functions to be given
  1651 directly (as in HOL) over datatypes and the natural numbers;
  1652 
  1653 * new tactics induct_tac and exhaust_tac for induction (or case
  1654 analysis) over datatypes and the natural numbers;
  1655 
  1656 * the datatype declaration of type T now defines the recursor T_rec;
  1657 
  1658 * simplification automatically does freeness reasoning for datatype
  1659 constructors;
  1660 
  1661 * automatic type-inference, with AddTCs command to insert new
  1662 type-checking rules;
  1663 
  1664 * datatype introduction rules are now added as Safe Introduction rules
  1665 to the claset;
  1666 
  1667 * the syntax "if P then x else y" is now available in addition to
  1668 if(P,x,y);
  1669 
  1670 
  1671 *** Internal programming interfaces ***
  1672 
  1673 * tuned simplifier trace output; new flag debug_simp;
  1674 
  1675 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1676 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1677 
  1678 * AxClass.axclass_tac lost the theory argument;
  1679 
  1680 * tuned current_goals_markers semantics: begin / end goal avoids
  1681 printing empty lines;
  1682 
  1683 * removed prs and prs_fn hook, which was broken because it did not
  1684 include \n in its semantics, forcing writeln to add one
  1685 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1686 string -> unit if you really want to output text without newline;
  1687 
  1688 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1689 plain output, interface builders may have to enable 'isabelle_font'
  1690 mode to get Isabelle font glyphs as before;
  1691 
  1692 * refined token_translation interface; INCOMPATIBILITY: output length
  1693 now of type real instead of int;
  1694 
  1695 * theory loader actions may be traced via new ThyInfo.add_hook
  1696 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1697 your own database of information attached to *whole* theories -- as
  1698 opposed to intra-theory data slots offered via TheoryDataFun;
  1699 
  1700 * proper handling of dangling sort hypotheses (at last!);
  1701 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1702 extra sort hypotheses that can be witnessed from the type signature;
  1703 the force_strip_shyps flag is gone, any remaining shyps are simply
  1704 left in the theorem (with a warning issued by strip_shyps_warning);
  1705 
  1706 
  1707 
  1708 New in Isabelle98-1 (October 1998)
  1709 ----------------------------------
  1710 
  1711 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1712 
  1713 * several changes of automated proof tools;
  1714 
  1715 * HOL: major changes to the inductive and datatype packages, including
  1716 some minor incompatibilities of theory syntax;
  1717 
  1718 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1719 called `inj_on';
  1720 
  1721 * HOL: removed duplicate thms in Arith:
  1722   less_imp_add_less  should be replaced by  trans_less_add1
  1723   le_imp_add_le      should be replaced by  trans_le_add1
  1724 
  1725 * HOL: unary minus is now overloaded (new type constraints may be
  1726 required);
  1727 
  1728 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1729 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1730 now taken as an integer constant.
  1731 
  1732 * Pure: ML function 'theory_of' renamed to 'theory';
  1733 
  1734 
  1735 *** Proof tools ***
  1736 
  1737 * Simplifier:
  1738   1. Asm_full_simp_tac is now more aggressive.
  1739      1. It will sometimes reorient premises if that increases their power to
  1740         simplify.
  1741      2. It does no longer proceed strictly from left to right but may also
  1742         rotate premises to achieve further simplification.
  1743      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1744      old Asm_full_simp_tac in that it does not rotate premises.
  1745   2. The simplifier now knows a little bit about nat-arithmetic.
  1746 
  1747 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1748 allows for selected deletion of wrappers, by introduction of names for
  1749 wrapper functionals.  This implies that addbefore, addSbefore,
  1750 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1751 and that adding two tactics with the same name overwrites the first
  1752 one (emitting a warning).
  1753   type wrapper = (int -> tactic) -> (int -> tactic)
  1754   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1755   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1756   delWrapper, delSWrapper: claset *  string            -> claset
  1757   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1758 
  1759 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1760 semantics; addbefore now affects only the unsafe part of step_tac
  1761 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1762 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1763 by Force_tac;
  1764 
  1765 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1766 compWrapper; added safe wrapper (and access functions for it);
  1767 
  1768 * HOL/split_all_tac is now much faster and fails if there is nothing
  1769 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1770 and the names of the automatically generated variables have changed.
  1771 split_all_tac has moved within claset() from unsafe wrappers to safe
  1772 wrappers, which means that !!-bound variables are split much more
  1773 aggressively, and safe_tac and clarify_tac now split such variables.
  1774 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1775 Note: the same holds for record_split_tac, which does the job of
  1776 split_all_tac for record fields.
  1777 
  1778 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1779 permanently to the default simpset using Addsplits just like
  1780 Addsimps. They can be removed via Delsplits just like
  1781 Delsimps. Lower-case versions are also available.
  1782 
  1783 * HOL/Simplifier: The rule split_if is now part of the default
  1784 simpset. This means that the simplifier will eliminate all occurrences
  1785 of if-then-else in the conclusion of a goal. To prevent this, you can
  1786 either remove split_if completely from the default simpset by
  1787 `Delsplits [split_if]' or remove it in a specific call of the
  1788 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1789 other case splitting rules to/from the default simpset: every datatype
  1790 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1791 t is the name of the datatype).
  1792 
  1793 * Classical reasoner / Simplifier combination: new force_tac (and
  1794 derivatives Force_tac, force) combines rewriting and classical
  1795 reasoning (and whatever other tools) similarly to auto_tac, but is
  1796 aimed to solve the given subgoal completely.
  1797 
  1798 
  1799 *** General ***
  1800 
  1801 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1802 and `goalw': the theory is no longer needed as an explicit argument -
  1803 the current theory context is used; assumptions are no longer returned
  1804 at the ML-level unless one of them starts with ==> or !!; it is
  1805 recommended to convert to these new commands using isatool fixgoal
  1806 (backup your sources first!);
  1807 
  1808 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1809 the current theory context, and 'theory' to lookup stored theories;
  1810 
  1811 * new theory section 'locale' for declaring constants, assumptions and
  1812 definitions that have local scope;
  1813 
  1814 * new theory section 'nonterminals' for purely syntactic types;
  1815 
  1816 * new theory section 'setup' for generic ML setup functions
  1817 (e.g. package initialization);
  1818 
  1819 * the distribution now includes Isabelle icons: see
  1820 lib/logo/isabelle-{small,tiny}.xpm;
  1821 
  1822 * isatool install - install binaries with absolute references to
  1823 ISABELLE_HOME/bin;
  1824 
  1825 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1826 
  1827 * print mode 'emacs' reserved for Isamode;
  1828 
  1829 * support multiple print (ast) translations per constant name;
  1830 
  1831 * theorems involving oracles are now printed with a suffixed [!];
  1832 
  1833 
  1834 *** HOL ***
  1835 
  1836 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1837 
  1838 * HOL/inductive package reorganized and improved: now supports mutual
  1839 definitions such as
  1840 
  1841   inductive EVEN ODD
  1842     intrs
  1843       null "0 : EVEN"
  1844       oddI "n : EVEN ==> Suc n : ODD"
  1845       evenI "n : ODD ==> Suc n : EVEN"
  1846 
  1847 new theorem list "elims" contains an elimination rule for each of the
  1848 recursive sets; inductive definitions now handle disjunctive premises
  1849 correctly (also ZF);
  1850 
  1851 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1852 "mutual_induct" no longer exists - the induction rule is always
  1853 contained in "induct";
  1854 
  1855 
  1856 * HOL/datatype package re-implemented and greatly improved: now
  1857 supports mutually recursive datatypes such as
  1858 
  1859   datatype
  1860     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1861             | SUM ('a aexp) ('a aexp)
  1862             | DIFF ('a aexp) ('a aexp)
  1863             | NUM 'a
  1864   and
  1865     'a bexp = LESS ('a aexp) ('a aexp)
  1866             | AND ('a bexp) ('a bexp)
  1867             | OR ('a bexp) ('a bexp)
  1868 
  1869 as well as indirectly recursive datatypes such as
  1870 
  1871   datatype
  1872     ('a, 'b) term = Var 'a
  1873                   | App 'b ((('a, 'b) term) list)
  1874 
  1875 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1876 induction on mutually / indirectly recursive datatypes.
  1877 
  1878 Primrec equations are now stored in theory and can be accessed via
  1879 <function_name>.simps.
  1880 
  1881 INCOMPATIBILITIES:
  1882 
  1883   - Theories using datatypes must now have theory Datatype as an
  1884     ancestor.
  1885   - The specific <typename>.induct_tac no longer exists - use the
  1886     generic induct_tac instead.
  1887   - natE has been renamed to nat.exhaust - use exhaust_tac
  1888     instead of res_inst_tac ... natE. Note that the variable
  1889     names in nat.exhaust differ from the names in natE, this
  1890     may cause some "fragile" proofs to fail.
  1891   - The theorems split_<typename>_case and split_<typename>_case_asm
  1892     have been renamed to <typename>.split and <typename>.split_asm.
  1893   - Since default sorts of type variables are now handled correctly,
  1894     some datatype definitions may have to be annotated with explicit
  1895     sort constraints.
  1896   - Primrec definitions no longer require function name and type
  1897     of recursive argument.
  1898 
  1899 Consider using isatool fixdatatype to adapt your theories and proof
  1900 scripts to the new package (backup your sources first!).
  1901 
  1902 
  1903 * HOL/record package: considerably improved implementation; now
  1904 includes concrete syntax for record types, terms, updates; theorems
  1905 for surjective pairing and splitting !!-bound record variables; proof
  1906 support is as follows:
  1907 
  1908   1) standard conversions (selectors or updates applied to record
  1909 constructor terms) are part of the standard simpset;
  1910 
  1911   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1912 made part of standard simpset and claset via addIffs;
  1913 
  1914   3) a tactic for record field splitting (record_split_tac) is part of
  1915 the standard claset (addSWrapper);
  1916 
  1917 To get a better idea about these rules you may retrieve them via
  1918 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1919 the name of your record type.
  1920 
  1921 The split tactic 3) conceptually simplifies by the following rule:
  1922 
  1923   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1924 
  1925 Thus any record variable that is bound by meta-all will automatically
  1926 blow up into some record constructor term, consequently the
  1927 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1928 solve record problems automatically.
  1929 
  1930 
  1931 * reorganized the main HOL image: HOL/Integ and String loaded by
  1932 default; theory Main includes everything;
  1933 
  1934 * automatic simplification of integer sums and comparisons, using cancellation;
  1935 
  1936 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1937 
  1938 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1939 
  1940 * many new identities for unions, intersections, set difference, etc.;
  1941 
  1942 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1943 called split_if, split_split, split_sum_case and split_nat_case (to go
  1944 with add/delsplits);
  1945 
  1946 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1947 (?x::unit) = (); this is made part of the default simpset, which COULD
  1948 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1949 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1950 unit_abs_eta_conv is added in order to counter the effect of
  1951 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1952 %u.f();
  1953 
  1954 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1955 makes more sense);
  1956 
  1957 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1958   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1959   disjointness reasoning but breaking a few old proofs.
  1960 
  1961 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1962 to 'converse' from 'inverse' (for compatibility with ZF and some
  1963 literature);
  1964 
  1965 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1966 the well-founded relation;
  1967 
  1968 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1969     Compl A.  The "Compl" syntax remains available as input syntax for this
  1970     release ONLY.
  1971 
  1972 * HOL/Update: new theory of function updates:
  1973     f(a:=b) == %x. if x=a then b else f x
  1974 may also be iterated as in f(a:=b,c:=d,...);
  1975 
  1976 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1977 
  1978 * HOL/List:
  1979   - new function list_update written xs[i:=v] that updates the i-th
  1980     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1981   - new function `upt' written [i..j(] which generates the list
  1982     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1983     bound write [i..j], which is a shorthand for [i..j+1(].
  1984   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1985 
  1986 * HOL/Arith:
  1987   - removed 'pred' (predecessor) function;
  1988   - generalized some theorems about n-1;
  1989   - many new laws about "div" and "mod";
  1990   - new laws about greatest common divisors (see theory ex/Primes);
  1991 
  1992 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1993 instead of "inverse";
  1994 
  1995 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1996   of the multiset ordering;
  1997 
  1998 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1999   (not included by default);
  2000 
  2001 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2002 
  2003 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2004   programs, i.e. different program variables may have different types.
  2005 
  2006 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2007   [previously, this check worked only if the rewrite rule was unconditional]
  2008   Now rew can involve either definitions or equalities (either == or =).
  2009 
  2010 
  2011 *** ZF ***
  2012 
  2013 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2014   only the theorems proved on ZF.ML;
  2015 
  2016 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2017   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2018   disjointness reasoning but breaking a few old proofs.
  2019 
  2020 * ZF/Update: new theory of function updates
  2021     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2022   may also be iterated as in f(a:=b,c:=d,...);
  2023 
  2024 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2025 
  2026 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2027   [previously, this check worked only if the rewrite rule was unconditional]
  2028   Now rew can involve either definitions or equalities (either == or =).
  2029 
  2030 * case_tac provided for compatibility with HOL
  2031     (like the old excluded_middle_tac, but with subgoals swapped)
  2032 
  2033 
  2034 *** Internal programming interfaces ***
  2035 
  2036 * Pure: several new basic modules made available for general use, see
  2037 also src/Pure/README;
  2038 
  2039 * improved the theory data mechanism to support encapsulation (data
  2040 kind name replaced by private Object.kind, acting as authorization
  2041 key); new type-safe user interface via functor TheoryDataFun; generic
  2042 print_data function becomes basically useless;
  2043 
  2044 * removed global_names compatibility flag -- all theory declarations
  2045 are qualified by default;
  2046 
  2047 * module Pure/Syntax now offers quote / antiquote translation
  2048 functions (useful for Hoare logic etc. with implicit dependencies);
  2049 see HOL/ex/Antiquote for an example use;
  2050 
  2051 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2052 cterm -> thm;
  2053 
  2054 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2055 subgoal;
  2056 
  2057 * Display.print_goals function moved to Locale.print_goals;
  2058 
  2059 * standard print function for goals supports current_goals_markers
  2060 variable for marking begin of proof, end of proof, start of goal; the
  2061 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2062 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2063 for example;
  2064 
  2065 
  2066 
  2067 New in Isabelle98 (January 1998)
  2068 --------------------------------
  2069 
  2070 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2071 
  2072 * changed lexical syntax of terms / types: dots made part of long
  2073 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2074 
  2075 * simpset (and claset) reference variable replaced by functions
  2076 simpset / simpset_ref;
  2077 
  2078 * no longer supports theory aliases (via merge) and non-trivial
  2079 implicit merge of thms' signatures;
  2080 
  2081 * most internal names of constants changed due to qualified names;
  2082 
  2083 * changed Pure/Sequence interface (see Pure/seq.ML);
  2084 
  2085 
  2086 *** General Changes ***
  2087 
  2088 * hierachically structured name spaces (for consts, types, axms, thms
  2089 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2090 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2091 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2092 long_names for fully qualified output names; NOTE: ML programs
  2093 (special tactics, packages etc.) referring to internal names may have
  2094 to be adapted to cope with fully qualified names; in case of severe
  2095 backward campatibility problems try setting 'global_names' at compile
  2096 time to have enrything declared within a flat name space; one may also
  2097 fine tune name declarations in theories via the 'global' and 'local'
  2098 section;
  2099 
  2100 * reimplemented the implicit simpset and claset using the new anytype
  2101 data filed in signatures; references simpset:simpset ref etc. are
  2102 replaced by functions simpset:unit->simpset and
  2103 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2104 to patch your ML files accordingly;
  2105 
  2106 * HTML output now includes theory graph data for display with Java
  2107 applet or isatool browser; data generated automatically via isatool
  2108 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2109 
  2110 * defs may now be conditional; improved rewrite_goals_tac to handle
  2111 conditional equations;
  2112 
  2113 * defs now admits additional type arguments, using TYPE('a) syntax;
  2114 
  2115 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2116 creates a new theory node; implicit merge of thms' signatures is
  2117 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2118 transfer:theory->thm->thm in (rare) cases;
  2119 
  2120 * improved handling of draft signatures / theories; draft thms (and
  2121 ctyps, cterms) are automatically promoted to real ones;
  2122 
  2123 * slightly changed interfaces for oracles: admit many per theory, named
  2124 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2125 
  2126 * print_goals: optional output of const types (set show_consts and
  2127 show_types);
  2128 
  2129 * improved output of warnings (###) and errors (***);
  2130 
  2131 * subgoal_tac displays a warning if the new subgoal has type variables;
  2132 
  2133 * removed old README and Makefiles;
  2134 
  2135 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2136 
  2137 * removed obsolete init_pps and init_database;
  2138 
  2139 * deleted the obsolete tactical STATE, which was declared by
  2140     fun STATE tacfun st = tacfun st st;
  2141 
  2142 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2143 (which abbreviates $HOME);
  2144 
  2145 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2146 use isatool fixseq to adapt your ML programs (this works for fully
  2147 qualified references to the Sequence structure only!);
  2148 
  2149 * use_thy no longer requires writable current directory; it always
  2150 reloads .ML *and* .thy file, if either one is out of date;
  2151 
  2152 
  2153 *** Classical Reasoner ***
  2154 
  2155 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2156 tactics that use classical reasoning to simplify a subgoal without
  2157 splitting it into several subgoals;
  2158 
  2159 * Safe_tac: like safe_tac but uses the default claset;
  2160 
  2161 
  2162 *** Simplifier ***
  2163 
  2164 * added simplification meta rules:
  2165     (asm_)(full_)simplify: simpset -> thm -> thm;
  2166 
  2167 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2168 logics (again);
  2169 
  2170 * added prems argument to simplification procedures;
  2171 
  2172 * HOL, FOL, ZF: added infix function `addsplits':
  2173   instead of `<simpset> setloop (split_tac <thms>)'
  2174   you can simply write `<simpset> addsplits <thms>'
  2175 
  2176 
  2177 *** Syntax ***
  2178 
  2179 * TYPE('a) syntax for type reflection terms;
  2180 
  2181 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2182 
  2183 * pretty printer: changed order of mixfix annotation preference (again!);
  2184 
  2185 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2186 
  2187 
  2188 *** HOL ***
  2189 
  2190 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2191   with `addloop' of the simplifier to faciliate case splitting in premises.
  2192 
  2193 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2194 
  2195 * HOL/Auth: new protocol proofs including some for the Internet
  2196   protocol TLS;
  2197 
  2198 * HOL/Map: new theory of `maps' a la VDM;
  2199 
  2200 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2201 cancelling out common nat summands from =, <, <= (in)equalities, or
  2202 differences; simplification procedures nat_cancel_factor for
  2203 cancelling common factor from =, <, <= (in)equalities over natural
  2204 sums; nat_cancel contains both kinds of procedures, it is installed by
  2205 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2206 
  2207 * HOL/simplifier: terms of the form
  2208   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2209   are rewritten to
  2210   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2211   and those of the form
  2212   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2213   are rewritten to
  2214   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2215 
  2216 * HOL/datatype
  2217   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2218 
  2219   P(t_case f1 ... fn x) =
  2220      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2221         ...
  2222        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2223      )
  2224 
  2225   and a theorem `split_t_case_asm' of the form
  2226 
  2227   P(t_case f1 ... fn x) =
  2228     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2229         ...
  2230        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2231      )
  2232   which can be added to a simpset via `addsplits'. The existing theorems
  2233   expand_list_case and expand_option_case have been renamed to
  2234   split_list_case and split_option_case.
  2235 
  2236 * HOL/Arithmetic:
  2237   - `pred n' is automatically converted to `n-1'.
  2238     Users are strongly encouraged not to use `pred' any longer,
  2239     because it will disappear altogether at some point.
  2240   - Users are strongly encouraged to write "0 < n" rather than
  2241     "n ~= 0". Theorems and proof tools have been modified towards this
  2242     `standard'.
  2243 
  2244 * HOL/Lists:
  2245   the function "set_of_list" has been renamed "set" (and its theorems too);
  2246   the function "nth" now takes its arguments in the reverse order and
  2247   has acquired the infix notation "!" as in "xs!n".
  2248 
  2249 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2250 
  2251 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2252   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2253 
  2254 * HOL/record: extensible records with schematic structural subtyping
  2255 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2256 still lacks various theorems and concrete record syntax;
  2257 
  2258 
  2259 *** HOLCF ***
  2260 
  2261 * removed "axioms" and "generated by" sections;
  2262 
  2263 * replaced "ops" section by extended "consts" section, which is capable of
  2264   handling the continuous function space "->" directly;
  2265 
  2266 * domain package:
  2267   . proves theorems immediately and stores them in the theory,
  2268   . creates hierachical name space,
  2269   . now uses normal mixfix annotations (instead of cinfix...),
  2270   . minor changes to some names and values (for consistency),
  2271   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2272   . separator between mutual domain defs: changed "," to "and",
  2273   . improved handling of sort constraints;  now they have to
  2274     appear on the left-hand side of the equations only;
  2275 
  2276 * fixed LAM <x,y,zs>.b syntax;
  2277 
  2278 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2279 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2280 
  2281 
  2282 *** FOL and ZF ***
  2283 
  2284 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2285   with `addloop' of the simplifier to faciliate case splitting in premises.
  2286 
  2287 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2288 in HOL, they strip ALL and --> from proved theorems;
  2289 
  2290 
  2291 
  2292 New in Isabelle94-8 (May 1997)
  2293 ------------------------------
  2294 
  2295 *** General Changes ***
  2296 
  2297 * new utilities to build / run / maintain Isabelle etc. (in parts
  2298 still somewhat experimental); old Makefiles etc. still functional;
  2299 
  2300 * new 'Isabelle System Manual';
  2301 
  2302 * INSTALL text, together with ./configure and ./build scripts;
  2303 
  2304 * reimplemented type inference for greater efficiency, better error
  2305 messages and clean internal interface;
  2306 
  2307 * prlim command for dealing with lots of subgoals (an easier way of
  2308 setting goals_limit);
  2309 
  2310 
  2311 *** Syntax ***
  2312 
  2313 * supports alternative (named) syntax tables (parser and pretty
  2314 printer); internal interface is provided by add_modesyntax(_i);
  2315 
  2316 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2317 be used in conjunction with the Isabelle symbol font; uses the
  2318 "symbols" syntax table;
  2319 
  2320 * added token_translation interface (may translate name tokens in
  2321 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2322 the current print_mode); IMPORTANT: user print translation functions
  2323 are responsible for marking newly introduced bounds
  2324 (Syntax.mark_boundT);
  2325 
  2326 * token translations for modes "xterm" and "xterm_color" that display
  2327 names in bold, underline etc. or colors (which requires a color
  2328 version of xterm);
  2329 
  2330 * infixes may now be declared with names independent of their syntax;
  2331 
  2332 * added typed_print_translation (like print_translation, but may
  2333 access type of constant);
  2334 
  2335 
  2336 *** Classical Reasoner ***
  2337 
  2338 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2339 some limitations.  Blast_tac...
  2340   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2341   + ignores elimination rules that don't have the correct format
  2342         (the conclusion MUST be a formula variable)
  2343   + ignores types, which can make HOL proofs fail
  2344   + rules must not require higher-order unification, e.g. apply_type in ZF
  2345     [message "Function Var's argument not a bound variable" relates to this]
  2346   + its proof strategy is more general but can actually be slower
  2347 
  2348 * substitution with equality assumptions no longer permutes other
  2349 assumptions;
  2350 
  2351 * minor changes in semantics of addafter (now called addaltern); renamed
  2352 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2353 (and access functions for it);
  2354 
  2355 * improved combination of classical reasoner and simplifier:
  2356   + functions for handling clasimpsets
  2357   + improvement of addss: now the simplifier is called _after_ the
  2358     safe steps.
  2359   + safe variant of addss called addSss: uses safe simplifications
  2360     _during_ the safe steps. It is more complete as it allows multiple
  2361     instantiations of unknowns (e.g. with slow_tac).
  2362 
  2363 *** Simplifier ***
  2364 
  2365 * added interface for simplification procedures (functions that
  2366 produce *proven* rewrite rules on the fly, depending on current
  2367 redex);
  2368 
  2369 * ordering on terms as parameter (used for ordered rewriting);
  2370 
  2371 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2372 
  2373 * the solver is now split into a safe and an unsafe part.
  2374 This should be invisible for the normal user, except that the
  2375 functions setsolver and addsolver have been renamed to setSolver and
  2376 addSolver; added safe_asm_full_simp_tac;
  2377 
  2378 
  2379 *** HOL ***
  2380 
  2381 * a generic induction tactic `induct_tac' which works for all datatypes and
  2382 also for type `nat';
  2383 
  2384 * a generic case distinction tactic `exhaust_tac' which works for all
  2385 datatypes and also for type `nat';
  2386 
  2387 * each datatype comes with a function `size';
  2388 
  2389 * patterns in case expressions allow tuple patterns as arguments to
  2390 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2391 
  2392 * primrec now also works with type nat;
  2393 
  2394 * recdef: a new declaration form, allows general recursive functions to be
  2395 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2396 
  2397 * the constant for negation has been renamed from "not" to "Not" to
  2398 harmonize with FOL, ZF, LK, etc.;
  2399 
  2400 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2401 infinite lists;
  2402 
  2403 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2404 
  2405 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2406 problems in commutative rings, using axiomatic type classes for + and *;
  2407 
  2408 * more examples in HOL/MiniML and HOL/Auth;
  2409 
  2410 * more default rewrite rules for quantifiers, union/intersection;
  2411 
  2412 * a new constant `arbitrary == @x.False';
  2413 
  2414 * HOLCF/IOA replaces old HOL/IOA;
  2415 
  2416 * HOLCF changes: derived all rules and arities
  2417   + axiomatic type classes instead of classes
  2418   + typedef instead of faking type definitions
  2419   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2420   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2421   + eliminated the types void, one, tr
  2422   + use unit lift and bool lift (with translations) instead of one and tr
  2423   + eliminated blift from Lift3.thy (use Def instead of blift)
  2424   all eliminated rules are derived as theorems --> no visible changes ;
  2425 
  2426 
  2427 *** ZF ***
  2428 
  2429 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2430 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2431 as ZF_cs addSIs [equalityI];
  2432 
  2433 
  2434 
  2435 New in Isabelle94-7 (November 96)
  2436 ---------------------------------
  2437 
  2438 * allowing negative levels (as offsets) in prlev and choplev;
  2439 
  2440 * super-linear speedup for large simplifications;
  2441 
  2442 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2443 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2444 FAIL); can suppress it using the command Delsimps (ex_simps @
  2445 all_simps); De Morgan laws are also now included, by default;
  2446 
  2447 * improved printing of ==>  :  ~:
  2448 
  2449 * new object-logic "Sequents" adds linear logic, while replacing LK
  2450 and Modal (thanks to Sara Kalvala);
  2451 
  2452 * HOL/Auth: correctness proofs for authentication protocols;
  2453 
  2454 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2455 examples on HOL/Auth);
  2456 
  2457 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2458 the rewriter and classical reasoner simultaneously;
  2459 
  2460 * function uresult no longer returns theorems in "standard" format;
  2461 regain previous version by: val uresult = standard o uresult;
  2462 
  2463 
  2464 
  2465 New in Isabelle94-6
  2466 -------------------
  2467 
  2468 * oracles -- these establish an interface between Isabelle and trusted
  2469 external reasoners, which may deliver results as theorems;
  2470 
  2471 * proof objects (in particular record all uses of oracles);
  2472 
  2473 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2474 
  2475 * "constdefs" section in theory files;
  2476 
  2477 * "primrec" section (HOL) no longer requires names;
  2478 
  2479 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2480 
  2481 
  2482 
  2483 New in Isabelle94-5
  2484 -------------------
  2485 
  2486 * reduced space requirements;
  2487 
  2488 * automatic HTML generation from theories;
  2489 
  2490 * theory files no longer require "..." (quotes) around most types;
  2491 
  2492 * new examples, including two proofs of the Church-Rosser theorem;
  2493 
  2494 * non-curried (1994) version of HOL is no longer distributed;
  2495 
  2496 
  2497 
  2498 New in Isabelle94-4
  2499 -------------------
  2500 
  2501 * greatly reduced space requirements;
  2502 
  2503 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2504 
  2505 * searchable theorem database (see the section "Retrieving theorems" on
  2506 page 8 of the Reference Manual);
  2507 
  2508 * new examples, including Grabczewski's monumental case study of the
  2509 Axiom of Choice;
  2510 
  2511 * The previous version of HOL renamed to Old_HOL;
  2512 
  2513 * The new version of HOL (previously called CHOL) uses a curried syntax
  2514 for functions.  Application looks like f a b instead of f(a,b);
  2515 
  2516 * Mutually recursive inductive definitions finally work in HOL;
  2517 
  2518 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2519 translates to the operator "split";
  2520 
  2521 
  2522 
  2523 New in Isabelle94-3
  2524 -------------------
  2525 
  2526 * new infix operator, addss, allowing the classical reasoner to
  2527 perform simplification at each step of its search.  Example:
  2528         fast_tac (cs addss ss)
  2529 
  2530 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2531 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2532 look like (a,b) instead of <a,b>;
  2533 
  2534 * PLEASE NOTE: CHOL will eventually replace HOL!
  2535 
  2536 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2537 It translates to the operator "split".  A new theory of integers is available;
  2538 
  2539 * In ZF, integer numerals now denote two's-complement binary integers.
  2540 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2541 
  2542 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2543 of the Axiom of Choice;
  2544 
  2545 
  2546 
  2547 New in Isabelle94-2
  2548 -------------------
  2549 
  2550 * Significantly faster resolution;
  2551 
  2552 * the different sections in a .thy file can now be mixed and repeated
  2553 freely;
  2554 
  2555 * Database of theorems for FOL, HOL and ZF.  New
  2556 commands including qed, qed_goal and bind_thm store theorems in the database.
  2557 
  2558 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2559 a given theory (thms_of), or find out what theory a theorem was proved in
  2560 (theory_of_thm);
  2561 
  2562 * Bugs fixed in the inductive definition and datatype packages;
  2563 
  2564 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2565 and HOL_dup_cs obsolete;
  2566 
  2567 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2568 have been removed;
  2569 
  2570 * Simpler definition of function space in ZF;
  2571 
  2572 * new results about cardinal and ordinal arithmetic in ZF;
  2573 
  2574 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2575 types;
  2576 
  2577 
  2578 $Id$