NEWS
author paulson
Mon May 05 18:34:16 2003 +0200 (2003-05-05)
changeset 13960 70f9158b6695
parent 13954 2e989faba65a
child 13966 2160abf7cfe7
permissions -rw-r--r--
Complex, etc
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/simplifier:
    10 
    11   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    12     Assumptions are now subject to complete mutual simplification,
    13     not just from left to right. The simplifier now preserves
    14     the order of assumptions.
    15 
    16     Potential INCOMPATIBILITY:
    17 
    18     -- simp sometimes diverges where the old version did
    19        not, e.g. invoking simp on the goal
    20 
    21         [| P (f x); y = x; f x = f y |] ==> Q
    22 
    23        now gives rise to the infinite reduction sequence
    24 
    25         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    26 
    27        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    28        kind of problem.
    29 
    30     -- Tactics combining classical reasoner and simplification (such as auto)
    31        are also affected by this change, because many of them rely on
    32        simp. They may sometimes diverge as well or yield a different numbers
    33        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    34        in case of problems. Sometimes subsequent calls to the classical
    35        reasoner will fail because a preceeding call to the simplifier too
    36        eagerly simplified the goal, e.g. deleted redundant premises.
    37 
    38   - The simplifier trace now shows the names of the applied rewrite rules
    39 
    40   - You can limit the number of recursive invocations of the simplifier
    41     during conditional rewriting (where the simplifie tries to solve the
    42     conditions before applying the rewrite rule):
    43     ML "simp_depth_limit := n"
    44     where n is an integer. Thus you can force termination where previously
    45     the simplifier would diverge.
    46 
    47   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
    48 
    49   - No longer aborts on failed congruence proof.  Instead, the
    50     congruence is ignored.
    51 
    52 * Pure: The main goal of the proof state is no longer shown by default, only
    53 the subgoals. This behaviour is controlled by a new flag.
    54    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
    55 (ML: Proof.show_main_goal).
    56 
    57 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
    58 rules whose conclusion matches subgoal 1:
    59       PG menu: Isabelle/Isar -> Show me -> matching rules
    60 The rules are ordered by how closely they match the subgoal.
    61 In particular, rules that solve a subgoal outright are displayed first
    62 (or rather last, the way they are printed).
    63 (ML: ProofGeneral.print_intros())
    64 
    65 * Pure: New flag trace_unify_fail causes unification to print
    66 diagnostic information (PG: in trace buffer) when it fails. This is
    67 useful for figuring out why single step proofs like rule, erule or
    68 assumption failed.
    69 
    70 * Pure: Locale specifications now produce predicate definitions
    71 according to the body of text (covering assumptions modulo local
    72 definitions); predicate "loc_axioms" covers newly introduced text,
    73 while "loc" is cumulative wrt. all included locale expressions; the
    74 latter view is presented only on export into the global theory
    75 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    76 on the old view without predicates;
    77 
    78 * Pure: predefined locales "var" and "struct" are useful for sharing
    79 parameters (as in CASL, for example); just specify something like
    80 ``var x + var y + struct M'' as import;
    81 
    82 * Pure: improved thms_containing: proper indexing of facts instead of
    83 raw theorems; check validity of results wrt. current name space;
    84 include local facts of proof configuration (also covers active
    85 locales), cover fixed variables in index; may use "_" in term
    86 specification; an optional limit for the number of printed facts may
    87 be given (the default is 40);
    88 
    89 * Pure: disallow duplicate fact bindings within new-style theory files
    90 (batch-mode only);
    91 
    92 * Provers: improved induct method: assumptions introduced by case
    93 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    94 the goal statement); "foo" still refers to all facts collectively;
    95 
    96 * Provers: the function blast.overloaded has been removed: all constants
    97 are regarded as potentially overloaded, which improves robustness in exchange
    98 for slight decrease in efficiency;
    99 
   100 * Provers/linorder: New generic prover for transitivity reasoning over
   101 linear orders.  Note: this prover is not efficient!
   102 
   103 * Isar: preview of problems to finish 'show' now produce an error
   104 rather than just a warning (in interactive mode);
   105 
   106 
   107 *** HOL ***
   108 
   109 * arith(_tac)
   110 
   111  - Produces a counter example if it cannot prove a goal.
   112    Note that the counter example may be spurious if the goal is not a formula
   113    of quantifier-free linear arithmetic.
   114    In ProofGeneral the counter example appears in the trace buffer.
   115 
   116  - Knows about div k and mod k where k is a numeral of type nat or int.
   117 
   118  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   119    linear arithmetic fails. This takes account of quantifiers and divisibility.
   120    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   121 
   122 * simp's arithmetic capabilities have been enhanced a bit: it now
   123 takes ~= in premises into account (by performing a case split);
   124 
   125 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   126 are distributed over a sum of terms;
   127 
   128 * New tactic "trans_tac" and method "trans" instantiate
   129 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   130 "<=", "<" and "="). 
   131 
   132 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   133 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   134 
   135 * 'typedef' command has new option "open" to suppress the set
   136 definition;
   137 
   138 * functions Min and Max on finite sets have been introduced (theory
   139 Finite_Set);
   140 
   141 * attribute [symmetric] now works for relations as well; it turns
   142 (x,y) : R^-1 into (y,x) : R, and vice versa;
   143 
   144 * induct over a !!-quantified statement (say !!x1..xn):
   145   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   146 
   147 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   148 %x. None. Warning: empty_def now refers to the previously hidden definition
   149 of the empty set.
   150 
   151 * Algebra: contains a new formalization of group theory, using locales with
   152 implicit structures.  Also a new, experimental summation operator for
   153 abelian groups;
   154 
   155 * Complex: new directory of the complex numbers with numeric constants, nonstandard complex numbers, and some complex analysis, standard and nonstandard (Jacques Fleuriot);
   156 
   157 * GroupTheory: deleted, since its material has been moved to Algebra;
   158 
   159 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques Fleuriot);
   160 
   161 * Real/HahnBanach: updated and adapted to locales;
   162 
   163 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad, Gray and
   164 Kramer);
   165 
   166 * UNITY: added the Meier-Sanders theory of progress sets;
   167 
   168 
   169 *** ZF ***
   170 
   171 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   172 universe, etc.);
   173 
   174 * Main ZF: virtually all theories converted to new-style format;
   175 
   176 
   177 *** ML ***
   178 
   179 * Pure: Tactic.prove provides sane interface for internal proofs;
   180 omits the infamous "standard" operation, so this is more appropriate
   181 than prove_goalw_cterm in many situations (e.g. in simprocs);
   182 
   183 * Pure: improved error reporting of simprocs;
   184 
   185 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   186 up simprocs;
   187 
   188 
   189 *** Document preparation ***
   190 
   191 * uses \par instead of \\ for line breaks in theory text. This may
   192 shift some page breaks in large documents. To get the old behaviour
   193 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   194 
   195 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   196 other packages
   197 
   198 * \<euro> now needs package babel/greek instead of marvosym (which
   199 broke \Rightarrow)
   200 
   201 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   202 textcomp package)
   203 
   204 
   205 New in Isabelle2002 (March 2002)
   206 --------------------------------
   207 
   208 *** Document preparation ***
   209 
   210 * greatly simplified document preparation setup, including more
   211 graceful interpretation of isatool usedir -i/-d/-D options, and more
   212 instructive isatool mkdir; users should basically be able to get
   213 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   214 users may run a separate document processing stage manually like this:
   215 "isatool usedir -D output HOL Test && isatool document Test/output";
   216 
   217 * theory dependency graph may now be incorporated into documents;
   218 isatool usedir -g true will produce session_graph.eps/.pdf for use
   219 with \includegraphics of LaTeX;
   220 
   221 * proper spacing of consecutive markup elements, especially text
   222 blocks after section headings;
   223 
   224 * support bold style (for single symbols only), input syntax is like
   225 this: "\<^bold>\<alpha>" or "\<^bold>A";
   226 
   227 * \<bullet> is now output as bold \cdot by default, which looks much
   228 better in printed text;
   229 
   230 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   231 note that these symbols are currently unavailable in Proof General /
   232 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   233 
   234 * isatool latex no longer depends on changed TEXINPUTS, instead
   235 isatool document copies the Isabelle style files to the target
   236 location;
   237 
   238 
   239 *** Isar ***
   240 
   241 * Pure/Provers: improved proof by cases and induction;
   242   - 'case' command admits impromptu naming of parameters (such as
   243     "case (Suc n)");
   244   - 'induct' method divinates rule instantiation from the inductive
   245     claim; no longer requires excessive ?P bindings for proper
   246     instantiation of cases;
   247   - 'induct' method properly enumerates all possibilities of set/type
   248     rules; as a consequence facts may be also passed through *type*
   249     rules without further ado;
   250   - 'induct' method now derives symbolic cases from the *rulified*
   251     rule (before it used to rulify cases stemming from the internal
   252     atomized version); this means that the context of a non-atomic
   253     statement becomes is included in the hypothesis, avoiding the
   254     slightly cumbersome show "PROP ?case" form;
   255   - 'induct' may now use elim-style induction rules without chaining
   256     facts, using ``missing'' premises from the goal state; this allows
   257     rules stemming from inductive sets to be applied in unstructured
   258     scripts, while still benefitting from proper handling of non-atomic
   259     statements; NB: major inductive premises need to be put first, all
   260     the rest of the goal is passed through the induction;
   261   - 'induct' proper support for mutual induction involving non-atomic
   262     rule statements (uses the new concept of simultaneous goals, see
   263     below);
   264   - append all possible rule selections, but only use the first
   265     success (no backtracking);
   266   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   267   - undeclared rule case names default to numbers 1, 2, 3, ...;
   268   - added 'print_induct_rules' (covered by help item in recent Proof
   269     General versions);
   270   - moved induct/cases attributes to Pure, methods to Provers;
   271   - generic method setup instantiated for FOL and HOL;
   272 
   273 * Pure: support multiple simultaneous goal statements, for example
   274 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   275 meta-level mechanism, this acts as if several individual goals had
   276 been stated separately; in particular common proof methods need to be
   277 repeated in order to cover all claims; note that a single elimination
   278 step is *not* sufficient to establish the two conjunctions, so this
   279 fails:
   280 
   281   assume "A & B" then have A and B ..   (*".." fails*)
   282 
   283 better use "obtain" in situations as above; alternative refer to
   284 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   285 
   286 * Pure: proper integration with ``locales''; unlike the original
   287 version by Florian Kammüller, Isar locales package high-level proof
   288 contexts rather than raw logical ones (e.g. we admit to include
   289 attributes everywhere); operations on locales include merge and
   290 rename; support for implicit arguments (``structures''); simultaneous
   291 type-inference over imports and text; see also HOL/ex/Locales.thy for
   292 some examples;
   293 
   294 * Pure: the following commands have been ``localized'', supporting a
   295 target locale specification "(in name)": 'lemma', 'theorem',
   296 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   297 stored both within the locale and at the theory level (exported and
   298 qualified by the locale name);
   299 
   300 * Pure: theory goals may now be specified in ``long'' form, with
   301 ad-hoc contexts consisting of arbitrary locale elements. for example
   302 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   303 definitions may be given, too); the result is a meta-level rule with
   304 the context elements being discharged in the obvious way;
   305 
   306 * Pure: new proof command 'using' allows to augment currently used
   307 facts after a goal statement ('using' is syntactically analogous to
   308 'apply', but acts on the goal's facts only); this allows chained facts
   309 to be separated into parts given before and after a claim, as in
   310 ``from a and b have C using d and e <proof>'';
   311 
   312 * Pure: renamed "antecedent" case to "rule_context";
   313 
   314 * Pure: new 'judgment' command records explicit information about the
   315 object-logic embedding (used by several tools internally); no longer
   316 use hard-wired "Trueprop";
   317 
   318 * Pure: added 'corollary' command;
   319 
   320 * Pure: fixed 'token_translation' command;
   321 
   322 * Pure: removed obsolete 'exported' attribute;
   323 
   324 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   325 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   326 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   327 
   328 * Pure: method 'atomize' presents local goal premises as object-level
   329 statements (atomic meta-level propositions); setup controlled via
   330 rewrite rules declarations of 'atomize' attribute; example
   331 application: 'induct' method with proper rule statements in improper
   332 proof *scripts*;
   333 
   334 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   335 now consider the syntactic context of assumptions, giving a better
   336 chance to get type-inference of the arguments right (this is
   337 especially important for locales);
   338 
   339 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   340 mode;
   341 
   342 * Pure/obtain: the formal conclusion "thesis", being marked as
   343 ``internal'', may no longer be reference directly in the text;
   344 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   345 situations;
   346 
   347 * Pure: generic 'sym' attribute which declares a rule both as pure
   348 'elim?' and for the 'symmetric' operation;
   349 
   350 * Pure: marginal comments ``--'' may now occur just anywhere in the
   351 text; the fixed correlation with particular command syntax has been
   352 discontinued;
   353 
   354 * Pure: new method 'rules' is particularly well-suited for proof
   355 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   356 but often produces more compact proof terms with less detours;
   357 
   358 * Pure/Provers/classical: simplified integration with pure rule
   359 attributes and methods; the classical "intro?/elim?/dest?"
   360 declarations coincide with the pure ones; the "rule" method no longer
   361 includes classically swapped intros; "intro" and "elim" methods no
   362 longer pick rules from the context; also got rid of ML declarations
   363 AddXIs/AddXEs/AddXDs; all of this has some potential for
   364 INCOMPATIBILITY;
   365 
   366 * Provers/classical: attribute 'swapped' produces classical inversions
   367 of introduction rules;
   368 
   369 * Provers/simplifier: 'simplified' attribute may refer to explicit
   370 rules instead of full simplifier context; 'iff' attribute handles
   371 conditional rules;
   372 
   373 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   374 
   375 * HOL: 'recdef' now fails on unfinished automated proofs, use
   376 "(permissive)" option to recover old behavior;
   377 
   378 * HOL: 'inductive' no longer features separate (collective) attributes
   379 for 'intros' (was found too confusing);
   380 
   381 * HOL: properly declared induction rules less_induct and
   382 wf_induct_rule;
   383 
   384 
   385 *** HOL ***
   386 
   387 * HOL: moved over to sane numeral syntax; the new policy is as
   388 follows:
   389 
   390   - 0 and 1 are polymorphic constants, which are defined on any
   391   numeric type (nat, int, real etc.);
   392 
   393   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   394   binary representation internally;
   395 
   396   - type nat has special constructor Suc, and generally prefers Suc 0
   397   over 1::nat and Suc (Suc 0) over 2::nat;
   398 
   399 This change may cause significant problems of INCOMPATIBILITY; here
   400 are some hints on converting existing sources:
   401 
   402   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   403   entities, so expressions involving "-" (unary or binary minus) need
   404   to be spaced properly;
   405 
   406   - existing occurrences of "1" may need to be constraint "1::nat" or
   407   even replaced by Suc 0; similar for old "2";
   408 
   409   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   410 
   411   - remove all special provisions on numerals in proofs;
   412 
   413 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   414 representation (depends on bin_arith_simps in the default context);
   415 
   416 * HOL: symbolic syntax for x^2 (numeral 2);
   417 
   418 * HOL: the class of all HOL types is now called "type" rather than
   419 "term"; INCOMPATIBILITY, need to adapt references to this type class
   420 in axclass/classes, instance/arities, and (usually rare) occurrences
   421 in typings (of consts etc.); internally the class is called
   422 "HOL.type", ML programs should refer to HOLogic.typeS;
   423 
   424 * HOL/record package improvements:
   425   - new derived operations "fields" to build a partial record section,
   426     "extend" to promote a fixed record to a record scheme, and
   427     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   428     declared as simp by default;
   429   - shared operations ("more", "fields", etc.) now need to be always
   430     qualified) --- potential INCOMPATIBILITY;
   431   - removed "make_scheme" operations (use "make" with "extend") --
   432     INCOMPATIBILITY;
   433   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   434   - provides cases/induct rules for use with corresponding Isar
   435     methods (for concrete records, record schemes, concrete more
   436     parts, and schematic more parts -- in that order);
   437   - internal definitions directly based on a light-weight abstract
   438     theory of product types over typedef rather than datatype;
   439 
   440 * HOL: generic code generator for generating executable ML code from
   441 specifications; specific support for HOL constructs such as inductive
   442 datatypes and sets, as well as recursive functions; can be invoked
   443 via 'generate_code' theory section;
   444 
   445 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   446 
   447 * HOL: consolidated and renamed several theories.  In particular:
   448 	Ord.thy has been absorbed into HOL.thy
   449 	String.thy has been absorbed into List.thy
   450  
   451 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   452 (beware of argument permutation!);
   453 
   454 * HOL: linorder_less_split superseded by linorder_cases;
   455 
   456 * HOL/List: "nodups" renamed to "distinct";
   457 
   458 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   459 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   460   - Ex_def has changed, now need to use some_eq_ex
   461 
   462 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   463 in this (rare) case use:
   464 
   465   delSWrapper "split_all_tac"
   466   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   467 
   468 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   469 MAY FAIL;
   470 
   471 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   472 Isabelle's type classes, ^ on functions and relations has too general
   473 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   474 necessary to attach explicit type constraints;
   475 
   476 * HOL/Relation: the prefix name of the infix "O" has been changed from
   477 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   478 renamed accordingly (eg "compI" -> "rel_compI").
   479 
   480 * HOL: syntax translations now work properly with numerals and records
   481 expressions;
   482 
   483 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   484 of "lam" -- INCOMPATIBILITY;
   485 
   486 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   487 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   488 renamed "Product_Type.unit";
   489 
   490 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   491 
   492 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   493 the "cases" method);
   494 
   495 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   496 Florian Kammüller);
   497 
   498 * HOL/IMP: updated and converted to new-style theory format; several
   499 parts turned into readable document, with proper Isar proof texts and
   500 some explanations (by Gerwin Klein);
   501 
   502 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   503 
   504 * HOL-Hyperreal is now a logic image;
   505 
   506 
   507 *** HOLCF ***
   508 
   509 * Isar: consts/constdefs supports mixfix syntax for continuous
   510 operations;
   511 
   512 * Isar: domain package adapted to new-style theory format, e.g. see
   513 HOLCF/ex/Dnat.thy;
   514 
   515 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   516 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   517 lift.induct_tac, always use UU instead of Undef;
   518 
   519 * HOLCF/IMP: updated and converted to new-style theory;
   520 
   521 
   522 *** ZF ***
   523 
   524 * Isar: proper integration of logic-specific tools and packages,
   525 including theory commands '(co)inductive', '(co)datatype',
   526 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   527 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   528 
   529 * theory Main no longer includes AC; for the Axiom of Choice, base
   530 your theory on Main_ZFC;
   531 
   532 * the integer library now covers quotients and remainders, with many
   533 laws relating division to addition, multiplication, etc.;
   534 
   535 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   536 typeless version of the formalism;
   537 
   538 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   539 format;
   540 
   541 * ZF/Induct: new directory for examples of inductive definitions,
   542 including theory Multiset for multiset orderings; converted to
   543 new-style theory format;
   544 
   545 * ZF: many new theorems about lists, ordinals, etc.;
   546 
   547 
   548 *** General ***
   549 
   550 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   551 variable proof controls level of detail: 0 = no proofs (only oracle
   552 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   553 also ref manual for further ML interfaces;
   554 
   555 * Pure/axclass: removed obsolete ML interface
   556 goal_subclass/goal_arity;
   557 
   558 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   559 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   560 separate tokens, so expressions involving minus need to be spaced
   561 properly;
   562 
   563 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   564 rather than "infixl" or "infixr";
   565 
   566 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   567 sort constraint specifications in type inference; e.g. "x::_::foo"
   568 ensures that the type of "x" is of sort "foo" (but not necessarily a
   569 type variable);
   570 
   571 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   572 control output of nested => (types); the default behavior is
   573 "type_brackets";
   574 
   575 * Pure/syntax: builtin parse translation for "_constify" turns valued
   576 tokens into AST constants;
   577 
   578 * Pure/syntax: prefer later declarations of translations and print
   579 translation functions; potential INCOMPATIBILITY: need to reverse
   580 multiple declarations for same syntax element constant;
   581 
   582 * Pure/show_hyps reset by default (in accordance to existing Isar
   583 practice);
   584 
   585 * Provers/classical: renamed addaltern to addafter, addSaltern to
   586 addSafter;
   587 
   588 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   589 as well;
   590 
   591 * system: tested support for MacOS X; should be able to get Isabelle +
   592 Proof General to work in a plain Terminal after installing Poly/ML
   593 (e.g. from the Isabelle distribution area) and GNU bash alone
   594 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   595 support requires further installations, e.g. from
   596 http://fink.sourceforge.net/);
   597 
   598 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   599 
   600 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   601 of 40 MB), cf. ML_OPTIONS;
   602 
   603 * system: Proof General keywords specification is now part of the
   604 Isabelle distribution (see etc/isar-keywords.el);
   605 
   606 * system: support for persistent Proof General sessions (refrain from
   607 outdating all loaded theories on startup); user may create writable
   608 logic images like this: ``isabelle -q HOL Test'';
   609 
   610 * system: smart selection of Isabelle process versus Isabelle
   611 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   612 run both "isabelle" and "Isabelle" even if file names are badly
   613 damaged (executable inspects the case of the first letter of its own
   614 name); added separate "isabelle-process" and "isabelle-interface";
   615 
   616 * system: refrain from any attempt at filtering input streams; no
   617 longer support ``8bit'' encoding of old isabelle font, instead proper
   618 iso-latin characters may now be used; the related isatools
   619 "symbolinput" and "nonascii" have disappeared as well;
   620 
   621 * system: removed old "xterm" interface (the print modes "xterm" and
   622 "xterm_color" are still available for direct use in a suitable
   623 terminal);
   624 
   625 
   626 
   627 New in Isabelle99-2 (February 2001)
   628 -----------------------------------
   629 
   630 *** Overview of INCOMPATIBILITIES ***
   631 
   632 * HOL: please note that theories in the Library and elsewhere often use the
   633 new-style (Isar) format; to refer to their theorems in an ML script you must
   634 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   635 
   636 * HOL: inductive package no longer splits induction rule aggressively,
   637 but only as far as specified by the introductions given; the old
   638 format may be recovered via ML function complete_split_rule or attribute
   639 'split_rule (complete)';
   640 
   641 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   642 gfp_Tarski to gfp_unfold;
   643 
   644 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   645 
   646 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   647 relation); infix "^^" has been renamed "``"; infix "``" has been
   648 renamed "`"; "univalent" has been renamed "single_valued";
   649 
   650 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   651 operation;
   652 
   653 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   654 
   655 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   656 
   657 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   658 consequence, it is no longer monotonic wrt. the local goal context
   659 (which is now passed through the inductive cases);
   660 
   661 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   662 \<gg> to \<ggreater>;
   663 
   664 
   665 *** Document preparation ***
   666 
   667 * \isabellestyle{NAME} selects version of Isabelle output (currently
   668 available: are "it" for near math-mode best-style output, "sl" for
   669 slanted text style, and "tt" for plain type-writer; if no
   670 \isabellestyle command is given, output is according to slanted
   671 type-writer);
   672 
   673 * support sub/super scripts (for single symbols only), input syntax is
   674 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   675 
   676 * some more standard symbols; see Appendix A of the system manual for
   677 the complete list of symbols defined in isabellesym.sty;
   678 
   679 * improved isabelle style files; more abstract symbol implementation
   680 (should now use \isamath{...} and \isatext{...} in custom symbol
   681 definitions);
   682 
   683 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   684 state; Note that presentation of goal states does not conform to
   685 actual human-readable proof documents.  Please do not include goal
   686 states into document output unless you really know what you are doing!
   687 
   688 * proper indentation of antiquoted output with proportional LaTeX
   689 fonts;
   690 
   691 * no_document ML operator temporarily disables LaTeX document
   692 generation;
   693 
   694 * isatool unsymbolize tunes sources for plain ASCII communication;
   695 
   696 
   697 *** Isar ***
   698 
   699 * Pure: Isar now suffers initial goal statements to contain unbound
   700 schematic variables (this does not conform to actual readable proof
   701 documents, due to unpredictable outcome and non-compositional proof
   702 checking); users who know what they are doing may use schematic goals
   703 for Prolog-style synthesis of proven results;
   704 
   705 * Pure: assumption method (an implicit finishing) now handles actual
   706 rules as well;
   707 
   708 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   709 initial goal, declare "that" only as Pure intro (only for single
   710 steps); the "that" rule assumption may now be involved in implicit
   711 finishing, thus ".." becomes a feasible for trivial obtains;
   712 
   713 * Pure: default proof step now includes 'intro_classes'; thus trivial
   714 instance proofs may be performed by "..";
   715 
   716 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   717 statements as well;
   718 
   719 * Pure: more robust selection of calculational rules;
   720 
   721 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   722 rule (as well as the assumption rule);
   723 
   724 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   725 lemmas, using the graph browser tool;
   726 
   727 * Pure: predict failure of "show" in interactive mode;
   728 
   729 * Pure: 'thms_containing' now takes actual terms as arguments;
   730 
   731 * HOL: improved method 'induct' --- now handles non-atomic goals
   732 (potential INCOMPATIBILITY); tuned error handling;
   733 
   734 * HOL: cases and induct rules now provide explicit hints about the
   735 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   736 any remaining facts are inserted into the goal verbatim;
   737 
   738 * HOL: local contexts (aka cases) may now contain term bindings as
   739 well; the 'cases' and 'induct' methods new provide a ?case binding for
   740 the result to be shown in each case;
   741 
   742 * HOL: added 'recdef_tc' command;
   743 
   744 * isatool convert assists in eliminating legacy ML scripts;
   745 
   746 
   747 *** HOL ***
   748 
   749 * HOL/Library: a collection of generic theories to be used together
   750 with main HOL; the theory loader path already includes this directory
   751 by default; the following existing theories have been moved here:
   752 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   753 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   754 
   755 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   756 modelling and verification task performed in Isabelle/HOL +
   757 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   758 
   759 * HOL/Algebra: special summation operator SUM no longer exists, it has
   760 been replaced by setsum; infix 'assoc' now has priority 50 (like
   761 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   762 'domain', this makes the theory consistent with mathematical
   763 literature;
   764 
   765 * HOL basics: added overloaded operations "inverse" and "divide"
   766 (infix "/"), syntax for generic "abs" operation, generic summation
   767 operator \<Sum>;
   768 
   769 * HOL/typedef: simplified package, provide more useful rules (see also
   770 HOL/subset.thy);
   771 
   772 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   773 now expressed as a proper nested rule (old-style tactic scripts may
   774 require atomize_strip_tac to cope with non-atomic premises);
   775 
   776 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   777 to "split_conv" (old name still available for compatibility);
   778 
   779 * HOL: improved concrete syntax for strings (e.g. allows translation
   780 rules with string literals);
   781 
   782 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   783  and Fleuriot's mechanization of analysis, including the transcendental
   784  functions for the reals;
   785 
   786 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   787 
   788 
   789 *** CTT ***
   790 
   791 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   792 "lam" is displayed as TWO lambda-symbols
   793 
   794 * CTT: theory Main now available, containing everything (that is, Bool
   795 and Arith);
   796 
   797 
   798 *** General ***
   799 
   800 * Pure: the Simplifier has been implemented properly as a derived rule
   801 outside of the actual kernel (at last!); the overall performance
   802 penalty in practical applications is about 50%, while reliability of
   803 the Isabelle inference kernel has been greatly improved;
   804 
   805 * print modes "brackets" and "no_brackets" control output of nested =>
   806 (types) and ==> (props); the default behaviour is "brackets";
   807 
   808 * Provers: fast_tac (and friends) now handle actual object-logic rules
   809 as assumptions as well;
   810 
   811 * system: support Poly/ML 4.0;
   812 
   813 * system: isatool install handles KDE version 1 or 2;
   814 
   815 
   816 
   817 New in Isabelle99-1 (October 2000)
   818 ----------------------------------
   819 
   820 *** Overview of INCOMPATIBILITIES ***
   821 
   822 * HOL: simplification of natural numbers is much changed; to partly
   823 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   824 issue the following ML commands:
   825 
   826   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   827   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   828 
   829 * HOL: simplification no longer dives into case-expressions; this is
   830 controlled by "t.weak_case_cong" for each datatype t;
   831 
   832 * HOL: nat_less_induct renamed to less_induct;
   833 
   834 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   835 fixsome to patch .thy and .ML sources automatically;
   836 
   837   select_equality  -> some_equality
   838   select_eq_Ex     -> some_eq_ex
   839   selectI2EX       -> someI2_ex
   840   selectI2         -> someI2
   841   selectI          -> someI
   842   select1_equality -> some1_equality
   843   Eps_sym_eq       -> some_sym_eq_trivial
   844   Eps_eq           -> some_eq_trivial
   845 
   846 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   847 
   848 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   849 instead);
   850 
   851 * HOL: the recursion equations generated by 'recdef' are now called
   852 f.simps instead of f.rules;
   853 
   854 * HOL: qed_spec_mp now also handles bounded ALL as well;
   855 
   856 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   857 sometimes be needed;
   858 
   859 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   860 
   861 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   862 
   863 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   864 product is now "<*>" instead of "Times"; the lexicographic product is
   865 now "<*lex*>" instead of "**";
   866 
   867 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   868 of main HOL, but was unused); better use HOL's datatype package;
   869 
   870 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   871 the old syntax may be recovered as follows:
   872 
   873   syntax (symbols)
   874     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   875       (infixl "\\<oplus>" 100)
   876 
   877 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   878 
   879 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   880 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   881 internally;
   882 
   883 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   884 changed from A/r to A//r;
   885 
   886 * ZF: new treatment of arithmetic (nat & int) may break some old
   887 proofs;
   888 
   889 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   890 rulify -> rule_format, elimify -> elim_format, ...);
   891 
   892 * Isar/Provers: intro/elim/dest attributes changed; renamed
   893 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   894 should have to change intro!! to intro? only); replaced "delrule" by
   895 "rule del";
   896 
   897 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   898 
   899 * Provers: strengthened force_tac by using new first_best_tac;
   900 
   901 * LaTeX document preparation: several changes of isabelle.sty (see
   902 lib/texinputs);
   903 
   904 
   905 *** Document preparation ***
   906 
   907 * formal comments (text blocks etc.) in new-style theories may now
   908 contain antiquotations of thm/prop/term/typ/text to be presented
   909 according to latex print mode; concrete syntax is like this:
   910 @{term[show_types] "f(x) = a + x"};
   911 
   912 * isatool mkdir provides easy setup of Isabelle session directories,
   913 including proper document sources;
   914 
   915 * generated LaTeX sources are now deleted after successful run
   916 (isatool document -c); may retain a copy somewhere else via -D option
   917 of isatool usedir;
   918 
   919 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   920 style files, achieving self-contained LaTeX sources and simplifying
   921 LaTeX debugging;
   922 
   923 * old-style theories now produce (crude) LaTeX output as well;
   924 
   925 * browser info session directories are now self-contained (may be put
   926 on WWW server seperately); improved graphs of nested sessions; removed
   927 graph for 'all sessions';
   928 
   929 * several improvements in isabelle style files; \isabellestyle{it}
   930 produces fake math mode output; \isamarkupheader is now \section by
   931 default; see lib/texinputs/isabelle.sty etc.;
   932 
   933 
   934 *** Isar ***
   935 
   936 * Isar/Pure: local results and corresponding term bindings are now
   937 subject to Hindley-Milner polymorphism (similar to ML); this
   938 accommodates incremental type-inference very nicely;
   939 
   940 * Isar/Pure: new derived language element 'obtain' supports
   941 generalized existence reasoning;
   942 
   943 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   944 support accumulation of results, without applying any rules yet;
   945 useful to collect intermediate results without explicit name
   946 references, and for use with transitivity rules with more than 2
   947 premises;
   948 
   949 * Isar/Pure: scalable support for case-analysis type proofs: new
   950 'case' language element refers to local contexts symbolically, as
   951 produced by certain proof methods; internally, case names are attached
   952 to theorems as "tags";
   953 
   954 * Isar/Pure: theory command 'hide' removes declarations from
   955 class/type/const name spaces;
   956 
   957 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   958 indicate potential overloading;
   959 
   960 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   961 
   962 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   963 "{a,b,c}" instead of {a,b,c};
   964 
   965 * Isar/Pure now provides its own version of intro/elim/dest
   966 attributes; useful for building new logics, but beware of confusion
   967 with the version in Provers/classical;
   968 
   969 * Isar/Pure: the local context of (non-atomic) goals is provided via
   970 case name 'antecedent';
   971 
   972 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   973 to the current context is now done automatically);
   974 
   975 * Isar/Pure: theory command 'method_setup' provides a simple interface
   976 for definining proof methods in ML;
   977 
   978 * Isar/Provers: intro/elim/dest attributes changed; renamed
   979 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   980 most cases, one should have to change intro!! to intro? only);
   981 replaced "delrule" by "rule del";
   982 
   983 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   984 'symmetric' attribute (the latter supercedes [RS sym]);
   985 
   986 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   987 method modifier); 'simp' method: 'only:' modifier removes loopers as
   988 well (including splits);
   989 
   990 * Isar/Provers: Simplifier and Classical methods now support all kind
   991 of modifiers used in the past, including 'cong', 'iff', etc.
   992 
   993 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   994 of Simplifier and Classical reasoner);
   995 
   996 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   997 now support named cases; major packages (inductive, datatype, primrec,
   998 recdef) support case names and properly name parameters;
   999 
  1000 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1001 monotonicity conditions are extracted to be proven at end of
  1002 calculations;
  1003 
  1004 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1005 method anyway;
  1006 
  1007 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1008 split_if split_if_asm; datatype package provides theorems foo.splits =
  1009 foo.split foo.split_asm for each datatype;
  1010 
  1011 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1012 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1013 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1014 use "(cases (simplified))" method in proper proof texts);
  1015 
  1016 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1017 
  1018 * Isar: names of theorems etc. may be natural numbers as well;
  1019 
  1020 * Isar: 'pr' command: optional arguments for goals_limit and
  1021 ProofContext.prems_limit; no longer prints theory contexts, but only
  1022 proof states;
  1023 
  1024 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1025 additional print modes to be specified; e.g. "pr(latex)" will print
  1026 proof state according to the Isabelle LaTeX style;
  1027 
  1028 * Isar: improved support for emulating tactic scripts, including proof
  1029 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1030 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1031 (for HOL datatypes);
  1032 
  1033 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1034 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1035 'proof method scripts' have to be in depth-first order;
  1036 
  1037 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1038 
  1039 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1040 should instead use individual commands for printing items
  1041 (print_commands, print_methods etc.);
  1042 
  1043 * Isar: added 'nothing' --- the empty list of theorems;
  1044 
  1045 
  1046 *** HOL ***
  1047 
  1048 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1049 corresponding virtual machine and a specification of its bytecode
  1050 verifier and a lightweight bytecode verifier, including proofs of
  1051 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1052 Cornelia Pusch (see also the homepage of project Bali at
  1053 http://isabelle.in.tum.de/Bali/);
  1054 
  1055 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1056 Clemens Ballarin;
  1057 
  1058 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1059 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1060 Rasmussen;
  1061 
  1062 * HOL/Lattice: fundamental concepts of lattice theory and order
  1063 structures, including duals, properties of bounds versus algebraic
  1064 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1065 Theorem for complete lattices etc.; may also serve as a demonstration
  1066 for abstract algebraic reasoning using axiomatic type classes, and
  1067 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1068 
  1069 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1070 von Oheimb;
  1071 
  1072 * HOL/IMPP: extension of IMP with local variables and mutually
  1073 recursive procedures, by David von Oheimb;
  1074 
  1075 * HOL/Lambda: converted into new-style theory and document;
  1076 
  1077 * HOL/ex/Multiquote: example of multiple nested quotations and
  1078 anti-quotations -- basically a generalized version of de-Bruijn
  1079 representation; very useful in avoiding lifting of operations;
  1080 
  1081 * HOL/record: added general record equality rule to simpset; fixed
  1082 select-update simplification procedure to handle extended records as
  1083 well; admit "r" as field name;
  1084 
  1085 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1086 other numeric types and also as the identity of groups, rings, etc.;
  1087 
  1088 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1089 Types nat and int belong to this axclass;
  1090 
  1091 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1092    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1093    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1094   two terms #m*u and #n*u are replaced by #(m+n)*u
  1095     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1096   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1097     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1098 
  1099 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1100 powerful prover for predicate logic but knows nothing of clasets; see
  1101 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1102 
  1103 * HOL: new version of "case_tac" subsumes both boolean case split and
  1104 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1105 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1106 
  1107 * HOL: simplification no longer dives into case-expressions: only the
  1108 selector expression is simplified, but not the remaining arms; to
  1109 enable full simplification of case-expressions for datatype t, you may
  1110 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1111 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1112 
  1113 * HOL/recdef: the recursion equations generated by 'recdef' for
  1114 function 'f' are now called f.simps instead of f.rules; if all
  1115 termination conditions are proved automatically, these simplification
  1116 rules are added to the simpset, as in primrec; rules may be named
  1117 individually as well, resulting in a separate list of theorems for
  1118 each equation;
  1119 
  1120 * HOL/While is a new theory that provides a while-combinator. It
  1121 permits the definition of tail-recursive functions without the
  1122 provision of a termination measure. The latter is necessary once the
  1123 invariant proof rule for while is applied.
  1124 
  1125 * HOL: new (overloaded) notation for the set of elements below/above
  1126 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1127 
  1128 * HOL: theorems impI, allI, ballI bound as "strip";
  1129 
  1130 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1131 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1132 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1133 
  1134 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1135 
  1136 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1137 main HOL, but was unused);
  1138 
  1139 * HOL: fewer consts declared as global (e.g. have to refer to
  1140 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1141 
  1142 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1143 in case of overlap with user translations (e.g. judgements over
  1144 tuples); (note that the underlying logical represenation is still
  1145 bogus);
  1146 
  1147 
  1148 *** ZF ***
  1149 
  1150 * ZF: simplification automatically cancels common terms in arithmetic
  1151 expressions over nat and int;
  1152 
  1153 * ZF: new treatment of nat to minimize type-checking: all operators
  1154 coerce their operands to a natural number using the function natify,
  1155 making the algebraic laws unconditional;
  1156 
  1157 * ZF: as above, for int: operators coerce their operands to an integer
  1158 using the function intify;
  1159 
  1160 * ZF: the integer library now contains many of the usual laws for the
  1161 orderings, including $<=, and monotonicity laws for $+ and $*;
  1162 
  1163 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1164 simplification;
  1165 
  1166 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1167 to the simplifier and classical reasoner simultaneously;
  1168 
  1169 
  1170 *** General ***
  1171 
  1172 * Provers: blast_tac now handles actual object-logic rules as
  1173 assumptions; note that auto_tac uses blast_tac internally as well;
  1174 
  1175 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1176 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1177 
  1178 * Provers: delrules now handles destruct rules as well (no longer need
  1179 explicit make_elim);
  1180 
  1181 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1182   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1183 use instead the strong form,
  1184   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1185 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1186 from destruct-rules;
  1187 
  1188 * Provers: Simplifier.easy_setup provides a fast path to basic
  1189 Simplifier setup for new object-logics;
  1190 
  1191 * Pure: AST translation rules no longer require constant head on LHS;
  1192 
  1193 * Pure: improved name spaces: ambiguous output is qualified; support
  1194 for hiding of names;
  1195 
  1196 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1197 XSYMBOL_HOME; no longer need to do manual configuration in most
  1198 situations;
  1199 
  1200 * system: compression of ML heaps images may now be controlled via -c
  1201 option of isabelle and isatool usedir (currently only observed by
  1202 Poly/ML);
  1203 
  1204 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1205 useful for remote X11);
  1206 
  1207 * system: provide TAGS file for Isabelle sources;
  1208 
  1209 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1210 order;
  1211 
  1212 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1213 timing flag supersedes proof_timing and Toplevel.trace;
  1214 
  1215 * ML: new combinators |>> and |>>> for incremental transformations
  1216 with secondary results (e.g. certain theory extensions):
  1217 
  1218 * ML: PureThy.add_defs gets additional argument to indicate potential
  1219 overloading (usually false);
  1220 
  1221 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1222 results;
  1223 
  1224 
  1225 
  1226 New in Isabelle99 (October 1999)
  1227 --------------------------------
  1228 
  1229 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1230 
  1231 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1232 are no longer simplified.  (This allows the simplifier to unfold recursive
  1233 functional programs.)  To restore the old behaviour, declare
  1234 
  1235     Delcongs [if_weak_cong];
  1236 
  1237 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1238 complement;
  1239 
  1240 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1241 
  1242 * HOL/datatype: mutual_induct_tac no longer exists --
  1243   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1244 
  1245 * HOL/typedef: fixed type inference for representing set; type
  1246 arguments now have to occur explicitly on the rhs as type constraints;
  1247 
  1248 * ZF: The con_defs part of an inductive definition may no longer refer
  1249 to constants declared in the same theory;
  1250 
  1251 * HOL, ZF: the function mk_cases, generated by the inductive
  1252 definition package, has lost an argument.  To simplify its result, it
  1253 uses the default simpset instead of a supplied list of theorems.
  1254 
  1255 * HOL/List: the constructors of type list are now Nil and Cons;
  1256 
  1257 * Simplifier: the type of the infix ML functions
  1258         setSSolver addSSolver setSolver addSolver
  1259 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1260 for packaging solvers. A solver is created via
  1261         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1262 where the string argument is only a comment.
  1263 
  1264 
  1265 *** Proof tools ***
  1266 
  1267 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1268 decision procedure for linear arithmetic. Currently it is used for
  1269 types `nat', `int', and `real' in HOL (see below); it can, should and
  1270 will be instantiated for other types and logics as well.
  1271 
  1272 * The simplifier now accepts rewrite rules with flexible heads, eg
  1273      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1274   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1275   matching.
  1276 
  1277 
  1278 *** General ***
  1279 
  1280 * New Isabelle/Isar subsystem provides an alternative to traditional
  1281 tactical theorem proving; together with the ProofGeneral/isar user
  1282 interface it offers an interactive environment for developing human
  1283 readable proof documents (Isar == Intelligible semi-automated
  1284 reasoning); for further information see isatool doc isar-ref,
  1285 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1286 
  1287 * improved and simplified presentation of theories: better HTML markup
  1288 (including colors), graph views in several sizes; isatool usedir now
  1289 provides a proper interface for user theories (via -P option); actual
  1290 document preparation based on (PDF)LaTeX is available as well (for
  1291 new-style theories only); see isatool doc system for more information;
  1292 
  1293 * native support for Proof General, both for classic Isabelle and
  1294 Isabelle/Isar;
  1295 
  1296 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1297 using the graph browser tool;
  1298 
  1299 * Isabelle manuals now also available as PDF;
  1300 
  1301 * theory loader rewritten from scratch (may not be fully
  1302 bug-compatible); old loadpath variable has been replaced by show_path,
  1303 add_path, del_path, reset_path functions; new operations such as
  1304 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1305 isatool doc ref);
  1306 
  1307 * improved isatool install: option -k creates KDE application icon,
  1308 option -p DIR installs standalone binaries;
  1309 
  1310 * added ML_PLATFORM setting (useful for cross-platform installations);
  1311 more robust handling of platform specific ML images for SML/NJ;
  1312 
  1313 * the settings environment is now statically scoped, i.e. it is never
  1314 created again in sub-processes invoked from isabelle, isatool, or
  1315 Isabelle;
  1316 
  1317 * path element specification '~~' refers to '$ISABELLE_HOME';
  1318 
  1319 * in locales, the "assumes" and "defines" parts may be omitted if
  1320 empty;
  1321 
  1322 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1323 long arrows);
  1324 
  1325 * new print_mode "HTML";
  1326 
  1327 * new flag show_tags controls display of tags of theorems (which are
  1328 basically just comments that may be attached by some tools);
  1329 
  1330 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1331 mode and goal output format:
  1332 
  1333 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1334 244c244
  1335 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1336 ---
  1337 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1338 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1339 181c181
  1340 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1341 ---
  1342 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1343 
  1344 * function bind_thms stores lists of theorems (cf. bind_thm);
  1345 
  1346 * new shorthand tactics ftac, eatac, datac, fatac;
  1347 
  1348 * qed (and friends) now accept "" as result name; in that case the
  1349 theorem is not stored, but proper checks and presentation of the
  1350 result still apply;
  1351 
  1352 * theorem database now also indexes constants "Trueprop", "all",
  1353 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1354 
  1355 
  1356 *** HOL ***
  1357 
  1358 ** HOL arithmetic **
  1359 
  1360 * There are now decision procedures for linear arithmetic over nat and
  1361 int:
  1362 
  1363 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1364 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1365 are treated as atomic; subformulae not involving type `nat' or `int'
  1366 are ignored; quantified subformulae are ignored unless they are
  1367 positive universal or negative existential. The tactic has to be
  1368 invoked by hand and can be a little bit slow. In particular, the
  1369 running time is exponential in the number of occurrences of `min' and
  1370 `max', and `-' on `nat'.
  1371 
  1372 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1373 (negated) (in)equalities among the premises and the conclusion into
  1374 account (i.e. no compound formulae) and does not know about `min' and
  1375 `max', and `-' on `nat'. It is fast and is used automatically by the
  1376 simplifier.
  1377 
  1378 NB: At the moment, these decision procedures do not cope with mixed
  1379 nat/int formulae where the two parts interact, such as `m < n ==>
  1380 int(m) < int(n)'.
  1381 
  1382 * HOL/Numeral provides a generic theory of numerals (encoded
  1383 efficiently as bit strings); setup for types nat/int/real is in place;
  1384 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1385 int, existing theories and proof scripts may require a few additional
  1386 type constraints;
  1387 
  1388 * integer division and remainder can now be performed on constant
  1389 arguments;
  1390 
  1391 * many properties of integer multiplication, division and remainder
  1392 are now available;
  1393 
  1394 * An interface to the Stanford Validity Checker (SVC) is available through the
  1395 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1396 are proved automatically.  SVC must be installed separately, and its results
  1397 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1398 invocation of the underlying oracle).  For SVC see
  1399   http://verify.stanford.edu/SVC
  1400 
  1401 * IsaMakefile: the HOL-Real target now builds an actual image;
  1402 
  1403 
  1404 ** HOL misc **
  1405 
  1406 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1407 (in Isabelle/Isar) -- by Gertrud Bauer;
  1408 
  1409 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1410 analysis for assembly languages with subtypes;
  1411 
  1412 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1413 -- avoids syntactic ambiguities and treats state, transition, and
  1414 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1415 changed syntax and (many) tactics;
  1416 
  1417 * HOL/inductive: Now also handles more general introduction rules such
  1418   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1419   theorems are now maintained within the theory (maintained via the
  1420   "mono" attribute);
  1421 
  1422 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1423   (using function types) such as
  1424 
  1425   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1426 
  1427 * HOL/record: record_simproc (part of the default simpset) takes care
  1428 of selectors applied to updated records; record_split_tac is no longer
  1429 part of the default claset; update_defs may now be removed from the
  1430 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1431 
  1432   claset_ref () := claset() addSWrapper record_split_wrapper;
  1433   Delsimprocs [record_simproc]
  1434 
  1435 * HOL/typedef: fixed type inference for representing set; type
  1436 arguments now have to occur explicitly on the rhs as type constraints;
  1437 
  1438 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1439 names rather than an ML expression;
  1440 
  1441 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1442 supplied later.  Program schemes can be defined, such as
  1443     "While B C s = (if B s then While B C (C s) else s)"
  1444 where the well-founded relation can be chosen after B and C have been given.
  1445 
  1446 * HOL/List: the constructors of type list are now Nil and Cons;
  1447 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1448 course, ML tools referring to List.list.op # etc. have to be adapted;
  1449 
  1450 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1451 disabled by default; run isabelle with option -m HOL to get back to
  1452 the original Gordon/HOL-style output;
  1453 
  1454 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1455 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1456 
  1457 * HOL basic syntax simplified (more orthogonal): all variants of
  1458 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1459 Eps operator is provided as well: "SOME x. P[x]";
  1460 
  1461 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1462 
  1463 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1464 thus available for user theories;
  1465 
  1466 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1467 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1468 time;
  1469 
  1470 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1471 several times and then mp;
  1472 
  1473 
  1474 *** LK ***
  1475 
  1476 * the notation <<...>> is now available as a notation for sequences of
  1477 formulas;
  1478 
  1479 * the simplifier is now installed
  1480 
  1481 * the axiom system has been generalized (thanks to Soren Heilmann)
  1482 
  1483 * the classical reasoner now has a default rule database
  1484 
  1485 
  1486 *** ZF ***
  1487 
  1488 * new primrec section allows primitive recursive functions to be given
  1489 directly (as in HOL) over datatypes and the natural numbers;
  1490 
  1491 * new tactics induct_tac and exhaust_tac for induction (or case
  1492 analysis) over datatypes and the natural numbers;
  1493 
  1494 * the datatype declaration of type T now defines the recursor T_rec;
  1495 
  1496 * simplification automatically does freeness reasoning for datatype
  1497 constructors;
  1498 
  1499 * automatic type-inference, with AddTCs command to insert new
  1500 type-checking rules;
  1501 
  1502 * datatype introduction rules are now added as Safe Introduction rules
  1503 to the claset;
  1504 
  1505 * the syntax "if P then x else y" is now available in addition to
  1506 if(P,x,y);
  1507 
  1508 
  1509 *** Internal programming interfaces ***
  1510 
  1511 * tuned simplifier trace output; new flag debug_simp;
  1512 
  1513 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1514 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1515 
  1516 * AxClass.axclass_tac lost the theory argument;
  1517 
  1518 * tuned current_goals_markers semantics: begin / end goal avoids
  1519 printing empty lines;
  1520 
  1521 * removed prs and prs_fn hook, which was broken because it did not
  1522 include \n in its semantics, forcing writeln to add one
  1523 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1524 string -> unit if you really want to output text without newline;
  1525 
  1526 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1527 plain output, interface builders may have to enable 'isabelle_font'
  1528 mode to get Isabelle font glyphs as before;
  1529 
  1530 * refined token_translation interface; INCOMPATIBILITY: output length
  1531 now of type real instead of int;
  1532 
  1533 * theory loader actions may be traced via new ThyInfo.add_hook
  1534 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1535 your own database of information attached to *whole* theories -- as
  1536 opposed to intra-theory data slots offered via TheoryDataFun;
  1537 
  1538 * proper handling of dangling sort hypotheses (at last!);
  1539 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1540 extra sort hypotheses that can be witnessed from the type signature;
  1541 the force_strip_shyps flag is gone, any remaining shyps are simply
  1542 left in the theorem (with a warning issued by strip_shyps_warning);
  1543 
  1544 
  1545 
  1546 New in Isabelle98-1 (October 1998)
  1547 ----------------------------------
  1548 
  1549 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1550 
  1551 * several changes of automated proof tools;
  1552 
  1553 * HOL: major changes to the inductive and datatype packages, including
  1554 some minor incompatibilities of theory syntax;
  1555 
  1556 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1557 called `inj_on';
  1558 
  1559 * HOL: removed duplicate thms in Arith:
  1560   less_imp_add_less  should be replaced by  trans_less_add1
  1561   le_imp_add_le      should be replaced by  trans_le_add1
  1562 
  1563 * HOL: unary minus is now overloaded (new type constraints may be
  1564 required);
  1565 
  1566 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1567 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1568 now taken as an integer constant.
  1569 
  1570 * Pure: ML function 'theory_of' renamed to 'theory';
  1571 
  1572 
  1573 *** Proof tools ***
  1574 
  1575 * Simplifier:
  1576   1. Asm_full_simp_tac is now more aggressive.
  1577      1. It will sometimes reorient premises if that increases their power to
  1578         simplify.
  1579      2. It does no longer proceed strictly from left to right but may also
  1580         rotate premises to achieve further simplification.
  1581      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1582      old Asm_full_simp_tac in that it does not rotate premises.
  1583   2. The simplifier now knows a little bit about nat-arithmetic.
  1584 
  1585 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1586 allows for selected deletion of wrappers, by introduction of names for
  1587 wrapper functionals.  This implies that addbefore, addSbefore,
  1588 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1589 and that adding two tactics with the same name overwrites the first
  1590 one (emitting a warning).
  1591   type wrapper = (int -> tactic) -> (int -> tactic)
  1592   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1593   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1594   delWrapper, delSWrapper: claset *  string            -> claset
  1595   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1596 
  1597 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1598 semantics; addbefore now affects only the unsafe part of step_tac
  1599 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1600 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1601 by Force_tac;
  1602 
  1603 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1604 compWrapper; added safe wrapper (and access functions for it);
  1605 
  1606 * HOL/split_all_tac is now much faster and fails if there is nothing
  1607 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1608 and the names of the automatically generated variables have changed.
  1609 split_all_tac has moved within claset() from unsafe wrappers to safe
  1610 wrappers, which means that !!-bound variables are split much more
  1611 aggressively, and safe_tac and clarify_tac now split such variables.
  1612 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1613 Note: the same holds for record_split_tac, which does the job of
  1614 split_all_tac for record fields.
  1615 
  1616 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1617 permanently to the default simpset using Addsplits just like
  1618 Addsimps. They can be removed via Delsplits just like
  1619 Delsimps. Lower-case versions are also available.
  1620 
  1621 * HOL/Simplifier: The rule split_if is now part of the default
  1622 simpset. This means that the simplifier will eliminate all occurrences
  1623 of if-then-else in the conclusion of a goal. To prevent this, you can
  1624 either remove split_if completely from the default simpset by
  1625 `Delsplits [split_if]' or remove it in a specific call of the
  1626 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1627 other case splitting rules to/from the default simpset: every datatype
  1628 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1629 t is the name of the datatype).
  1630 
  1631 * Classical reasoner / Simplifier combination: new force_tac (and
  1632 derivatives Force_tac, force) combines rewriting and classical
  1633 reasoning (and whatever other tools) similarly to auto_tac, but is
  1634 aimed to solve the given subgoal completely.
  1635 
  1636 
  1637 *** General ***
  1638 
  1639 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1640 and `goalw': the theory is no longer needed as an explicit argument -
  1641 the current theory context is used; assumptions are no longer returned
  1642 at the ML-level unless one of them starts with ==> or !!; it is
  1643 recommended to convert to these new commands using isatool fixgoal
  1644 (backup your sources first!);
  1645 
  1646 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1647 the current theory context, and 'theory' to lookup stored theories;
  1648 
  1649 * new theory section 'locale' for declaring constants, assumptions and
  1650 definitions that have local scope;
  1651 
  1652 * new theory section 'nonterminals' for purely syntactic types;
  1653 
  1654 * new theory section 'setup' for generic ML setup functions
  1655 (e.g. package initialization);
  1656 
  1657 * the distribution now includes Isabelle icons: see
  1658 lib/logo/isabelle-{small,tiny}.xpm;
  1659 
  1660 * isatool install - install binaries with absolute references to
  1661 ISABELLE_HOME/bin;
  1662 
  1663 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1664 
  1665 * print mode 'emacs' reserved for Isamode;
  1666 
  1667 * support multiple print (ast) translations per constant name;
  1668 
  1669 * theorems involving oracles are now printed with a suffixed [!];
  1670 
  1671 
  1672 *** HOL ***
  1673 
  1674 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1675 
  1676 * HOL/inductive package reorganized and improved: now supports mutual
  1677 definitions such as
  1678 
  1679   inductive EVEN ODD
  1680     intrs
  1681       null "0 : EVEN"
  1682       oddI "n : EVEN ==> Suc n : ODD"
  1683       evenI "n : ODD ==> Suc n : EVEN"
  1684 
  1685 new theorem list "elims" contains an elimination rule for each of the
  1686 recursive sets; inductive definitions now handle disjunctive premises
  1687 correctly (also ZF);
  1688 
  1689 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1690 "mutual_induct" no longer exists - the induction rule is always
  1691 contained in "induct";
  1692 
  1693 
  1694 * HOL/datatype package re-implemented and greatly improved: now
  1695 supports mutually recursive datatypes such as
  1696 
  1697   datatype
  1698     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1699             | SUM ('a aexp) ('a aexp)
  1700             | DIFF ('a aexp) ('a aexp)
  1701             | NUM 'a
  1702   and
  1703     'a bexp = LESS ('a aexp) ('a aexp)
  1704             | AND ('a bexp) ('a bexp)
  1705             | OR ('a bexp) ('a bexp)
  1706 
  1707 as well as indirectly recursive datatypes such as
  1708 
  1709   datatype
  1710     ('a, 'b) term = Var 'a
  1711                   | App 'b ((('a, 'b) term) list)
  1712 
  1713 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1714 induction on mutually / indirectly recursive datatypes.
  1715 
  1716 Primrec equations are now stored in theory and can be accessed via
  1717 <function_name>.simps.
  1718 
  1719 INCOMPATIBILITIES:
  1720 
  1721   - Theories using datatypes must now have theory Datatype as an
  1722     ancestor.
  1723   - The specific <typename>.induct_tac no longer exists - use the
  1724     generic induct_tac instead.
  1725   - natE has been renamed to nat.exhaust - use exhaust_tac
  1726     instead of res_inst_tac ... natE. Note that the variable
  1727     names in nat.exhaust differ from the names in natE, this
  1728     may cause some "fragile" proofs to fail.
  1729   - The theorems split_<typename>_case and split_<typename>_case_asm
  1730     have been renamed to <typename>.split and <typename>.split_asm.
  1731   - Since default sorts of type variables are now handled correctly,
  1732     some datatype definitions may have to be annotated with explicit
  1733     sort constraints.
  1734   - Primrec definitions no longer require function name and type
  1735     of recursive argument.
  1736 
  1737 Consider using isatool fixdatatype to adapt your theories and proof
  1738 scripts to the new package (backup your sources first!).
  1739 
  1740 
  1741 * HOL/record package: considerably improved implementation; now
  1742 includes concrete syntax for record types, terms, updates; theorems
  1743 for surjective pairing and splitting !!-bound record variables; proof
  1744 support is as follows:
  1745 
  1746   1) standard conversions (selectors or updates applied to record
  1747 constructor terms) are part of the standard simpset;
  1748 
  1749   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1750 made part of standard simpset and claset via addIffs;
  1751 
  1752   3) a tactic for record field splitting (record_split_tac) is part of
  1753 the standard claset (addSWrapper);
  1754 
  1755 To get a better idea about these rules you may retrieve them via
  1756 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1757 the name of your record type.
  1758 
  1759 The split tactic 3) conceptually simplifies by the following rule:
  1760 
  1761   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1762 
  1763 Thus any record variable that is bound by meta-all will automatically
  1764 blow up into some record constructor term, consequently the
  1765 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1766 solve record problems automatically.
  1767 
  1768 
  1769 * reorganized the main HOL image: HOL/Integ and String loaded by
  1770 default; theory Main includes everything;
  1771 
  1772 * automatic simplification of integer sums and comparisons, using cancellation;
  1773 
  1774 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1775 
  1776 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1777 
  1778 * many new identities for unions, intersections, set difference, etc.;
  1779 
  1780 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1781 called split_if, split_split, split_sum_case and split_nat_case (to go
  1782 with add/delsplits);
  1783 
  1784 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1785 (?x::unit) = (); this is made part of the default simpset, which COULD
  1786 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1787 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1788 unit_abs_eta_conv is added in order to counter the effect of
  1789 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1790 %u.f();
  1791 
  1792 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1793 makes more sense);
  1794 
  1795 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1796   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1797   disjointness reasoning but breaking a few old proofs.
  1798 
  1799 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1800 to 'converse' from 'inverse' (for compatibility with ZF and some
  1801 literature);
  1802 
  1803 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1804 the well-founded relation;
  1805 
  1806 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1807     Compl A.  The "Compl" syntax remains available as input syntax for this
  1808     release ONLY.
  1809 
  1810 * HOL/Update: new theory of function updates:
  1811     f(a:=b) == %x. if x=a then b else f x
  1812 may also be iterated as in f(a:=b,c:=d,...);
  1813 
  1814 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1815 
  1816 * HOL/List:
  1817   - new function list_update written xs[i:=v] that updates the i-th
  1818     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1819   - new function `upt' written [i..j(] which generates the list
  1820     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1821     bound write [i..j], which is a shorthand for [i..j+1(].
  1822   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1823 
  1824 * HOL/Arith:
  1825   - removed 'pred' (predecessor) function;
  1826   - generalized some theorems about n-1;
  1827   - many new laws about "div" and "mod";
  1828   - new laws about greatest common divisors (see theory ex/Primes);
  1829 
  1830 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1831 instead of "inverse";
  1832 
  1833 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1834   of the multiset ordering;
  1835 
  1836 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1837   (not included by default);
  1838 
  1839 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1840 
  1841 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1842   programs, i.e. different program variables may have different types.
  1843 
  1844 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1845   [previously, this check worked only if the rewrite rule was unconditional]
  1846   Now rew can involve either definitions or equalities (either == or =).
  1847 
  1848 
  1849 *** ZF ***
  1850 
  1851 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1852   only the theorems proved on ZF.ML;
  1853 
  1854 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1855   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1856   disjointness reasoning but breaking a few old proofs.
  1857 
  1858 * ZF/Update: new theory of function updates
  1859     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1860   may also be iterated as in f(a:=b,c:=d,...);
  1861 
  1862 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1863 
  1864 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1865   [previously, this check worked only if the rewrite rule was unconditional]
  1866   Now rew can involve either definitions or equalities (either == or =).
  1867 
  1868 * case_tac provided for compatibility with HOL
  1869     (like the old excluded_middle_tac, but with subgoals swapped)
  1870 
  1871 
  1872 *** Internal programming interfaces ***
  1873 
  1874 * Pure: several new basic modules made available for general use, see
  1875 also src/Pure/README;
  1876 
  1877 * improved the theory data mechanism to support encapsulation (data
  1878 kind name replaced by private Object.kind, acting as authorization
  1879 key); new type-safe user interface via functor TheoryDataFun; generic
  1880 print_data function becomes basically useless;
  1881 
  1882 * removed global_names compatibility flag -- all theory declarations
  1883 are qualified by default;
  1884 
  1885 * module Pure/Syntax now offers quote / antiquote translation
  1886 functions (useful for Hoare logic etc. with implicit dependencies);
  1887 see HOL/ex/Antiquote for an example use;
  1888 
  1889 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1890 cterm -> thm;
  1891 
  1892 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1893 subgoal;
  1894 
  1895 * Display.print_goals function moved to Locale.print_goals;
  1896 
  1897 * standard print function for goals supports current_goals_markers
  1898 variable for marking begin of proof, end of proof, start of goal; the
  1899 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1900 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1901 for example;
  1902 
  1903 
  1904 
  1905 New in Isabelle98 (January 1998)
  1906 --------------------------------
  1907 
  1908 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1909 
  1910 * changed lexical syntax of terms / types: dots made part of long
  1911 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1912 
  1913 * simpset (and claset) reference variable replaced by functions
  1914 simpset / simpset_ref;
  1915 
  1916 * no longer supports theory aliases (via merge) and non-trivial
  1917 implicit merge of thms' signatures;
  1918 
  1919 * most internal names of constants changed due to qualified names;
  1920 
  1921 * changed Pure/Sequence interface (see Pure/seq.ML);
  1922 
  1923 
  1924 *** General Changes ***
  1925 
  1926 * hierachically structured name spaces (for consts, types, axms, thms
  1927 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1928 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1929 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1930 long_names for fully qualified output names; NOTE: ML programs
  1931 (special tactics, packages etc.) referring to internal names may have
  1932 to be adapted to cope with fully qualified names; in case of severe
  1933 backward campatibility problems try setting 'global_names' at compile
  1934 time to have enrything declared within a flat name space; one may also
  1935 fine tune name declarations in theories via the 'global' and 'local'
  1936 section;
  1937 
  1938 * reimplemented the implicit simpset and claset using the new anytype
  1939 data filed in signatures; references simpset:simpset ref etc. are
  1940 replaced by functions simpset:unit->simpset and
  1941 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1942 to patch your ML files accordingly;
  1943 
  1944 * HTML output now includes theory graph data for display with Java
  1945 applet or isatool browser; data generated automatically via isatool
  1946 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1947 
  1948 * defs may now be conditional; improved rewrite_goals_tac to handle
  1949 conditional equations;
  1950 
  1951 * defs now admits additional type arguments, using TYPE('a) syntax;
  1952 
  1953 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1954 creates a new theory node; implicit merge of thms' signatures is
  1955 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1956 transfer:theory->thm->thm in (rare) cases;
  1957 
  1958 * improved handling of draft signatures / theories; draft thms (and
  1959 ctyps, cterms) are automatically promoted to real ones;
  1960 
  1961 * slightly changed interfaces for oracles: admit many per theory, named
  1962 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1963 
  1964 * print_goals: optional output of const types (set show_consts and
  1965 show_types);
  1966 
  1967 * improved output of warnings (###) and errors (***);
  1968 
  1969 * subgoal_tac displays a warning if the new subgoal has type variables;
  1970 
  1971 * removed old README and Makefiles;
  1972 
  1973 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1974 
  1975 * removed obsolete init_pps and init_database;
  1976 
  1977 * deleted the obsolete tactical STATE, which was declared by
  1978     fun STATE tacfun st = tacfun st st;
  1979 
  1980 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1981 (which abbreviates $HOME);
  1982 
  1983 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1984 use isatool fixseq to adapt your ML programs (this works for fully
  1985 qualified references to the Sequence structure only!);
  1986 
  1987 * use_thy no longer requires writable current directory; it always
  1988 reloads .ML *and* .thy file, if either one is out of date;
  1989 
  1990 
  1991 *** Classical Reasoner ***
  1992 
  1993 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1994 tactics that use classical reasoning to simplify a subgoal without
  1995 splitting it into several subgoals;
  1996 
  1997 * Safe_tac: like safe_tac but uses the default claset;
  1998 
  1999 
  2000 *** Simplifier ***
  2001 
  2002 * added simplification meta rules:
  2003     (asm_)(full_)simplify: simpset -> thm -> thm;
  2004 
  2005 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2006 logics (again);
  2007 
  2008 * added prems argument to simplification procedures;
  2009 
  2010 * HOL, FOL, ZF: added infix function `addsplits':
  2011   instead of `<simpset> setloop (split_tac <thms>)'
  2012   you can simply write `<simpset> addsplits <thms>'
  2013 
  2014 
  2015 *** Syntax ***
  2016 
  2017 * TYPE('a) syntax for type reflection terms;
  2018 
  2019 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2020 
  2021 * pretty printer: changed order of mixfix annotation preference (again!);
  2022 
  2023 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2024 
  2025 
  2026 *** HOL ***
  2027 
  2028 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2029   with `addloop' of the simplifier to faciliate case splitting in premises.
  2030 
  2031 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2032 
  2033 * HOL/Auth: new protocol proofs including some for the Internet
  2034   protocol TLS;
  2035 
  2036 * HOL/Map: new theory of `maps' a la VDM;
  2037 
  2038 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2039 cancelling out common nat summands from =, <, <= (in)equalities, or
  2040 differences; simplification procedures nat_cancel_factor for
  2041 cancelling common factor from =, <, <= (in)equalities over natural
  2042 sums; nat_cancel contains both kinds of procedures, it is installed by
  2043 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2044 
  2045 * HOL/simplifier: terms of the form
  2046   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2047   are rewritten to
  2048   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2049   and those of the form
  2050   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2051   are rewritten to
  2052   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2053 
  2054 * HOL/datatype
  2055   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2056 
  2057   P(t_case f1 ... fn x) =
  2058      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2059         ...
  2060        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2061      )
  2062 
  2063   and a theorem `split_t_case_asm' of the form
  2064 
  2065   P(t_case f1 ... fn x) =
  2066     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2067         ...
  2068        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2069      )
  2070   which can be added to a simpset via `addsplits'. The existing theorems
  2071   expand_list_case and expand_option_case have been renamed to
  2072   split_list_case and split_option_case.
  2073 
  2074 * HOL/Arithmetic:
  2075   - `pred n' is automatically converted to `n-1'.
  2076     Users are strongly encouraged not to use `pred' any longer,
  2077     because it will disappear altogether at some point.
  2078   - Users are strongly encouraged to write "0 < n" rather than
  2079     "n ~= 0". Theorems and proof tools have been modified towards this
  2080     `standard'.
  2081 
  2082 * HOL/Lists:
  2083   the function "set_of_list" has been renamed "set" (and its theorems too);
  2084   the function "nth" now takes its arguments in the reverse order and
  2085   has acquired the infix notation "!" as in "xs!n".
  2086 
  2087 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2088 
  2089 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2090   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2091 
  2092 * HOL/record: extensible records with schematic structural subtyping
  2093 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2094 still lacks various theorems and concrete record syntax;
  2095 
  2096 
  2097 *** HOLCF ***
  2098 
  2099 * removed "axioms" and "generated by" sections;
  2100 
  2101 * replaced "ops" section by extended "consts" section, which is capable of
  2102   handling the continuous function space "->" directly;
  2103 
  2104 * domain package:
  2105   . proves theorems immediately and stores them in the theory,
  2106   . creates hierachical name space,
  2107   . now uses normal mixfix annotations (instead of cinfix...),
  2108   . minor changes to some names and values (for consistency),
  2109   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2110   . separator between mutual domain defs: changed "," to "and",
  2111   . improved handling of sort constraints;  now they have to
  2112     appear on the left-hand side of the equations only;
  2113 
  2114 * fixed LAM <x,y,zs>.b syntax;
  2115 
  2116 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2117 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2118 
  2119 
  2120 *** FOL and ZF ***
  2121 
  2122 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2123   with `addloop' of the simplifier to faciliate case splitting in premises.
  2124 
  2125 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2126 in HOL, they strip ALL and --> from proved theorems;
  2127 
  2128 
  2129 
  2130 New in Isabelle94-8 (May 1997)
  2131 ------------------------------
  2132 
  2133 *** General Changes ***
  2134 
  2135 * new utilities to build / run / maintain Isabelle etc. (in parts
  2136 still somewhat experimental); old Makefiles etc. still functional;
  2137 
  2138 * new 'Isabelle System Manual';
  2139 
  2140 * INSTALL text, together with ./configure and ./build scripts;
  2141 
  2142 * reimplemented type inference for greater efficiency, better error
  2143 messages and clean internal interface;
  2144 
  2145 * prlim command for dealing with lots of subgoals (an easier way of
  2146 setting goals_limit);
  2147 
  2148 
  2149 *** Syntax ***
  2150 
  2151 * supports alternative (named) syntax tables (parser and pretty
  2152 printer); internal interface is provided by add_modesyntax(_i);
  2153 
  2154 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2155 be used in conjunction with the Isabelle symbol font; uses the
  2156 "symbols" syntax table;
  2157 
  2158 * added token_translation interface (may translate name tokens in
  2159 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2160 the current print_mode); IMPORTANT: user print translation functions
  2161 are responsible for marking newly introduced bounds
  2162 (Syntax.mark_boundT);
  2163 
  2164 * token translations for modes "xterm" and "xterm_color" that display
  2165 names in bold, underline etc. or colors (which requires a color
  2166 version of xterm);
  2167 
  2168 * infixes may now be declared with names independent of their syntax;
  2169 
  2170 * added typed_print_translation (like print_translation, but may
  2171 access type of constant);
  2172 
  2173 
  2174 *** Classical Reasoner ***
  2175 
  2176 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2177 some limitations.  Blast_tac...
  2178   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2179   + ignores elimination rules that don't have the correct format
  2180         (the conclusion MUST be a formula variable)
  2181   + ignores types, which can make HOL proofs fail
  2182   + rules must not require higher-order unification, e.g. apply_type in ZF
  2183     [message "Function Var's argument not a bound variable" relates to this]
  2184   + its proof strategy is more general but can actually be slower
  2185 
  2186 * substitution with equality assumptions no longer permutes other
  2187 assumptions;
  2188 
  2189 * minor changes in semantics of addafter (now called addaltern); renamed
  2190 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2191 (and access functions for it);
  2192 
  2193 * improved combination of classical reasoner and simplifier:
  2194   + functions for handling clasimpsets
  2195   + improvement of addss: now the simplifier is called _after_ the
  2196     safe steps.
  2197   + safe variant of addss called addSss: uses safe simplifications
  2198     _during_ the safe steps. It is more complete as it allows multiple
  2199     instantiations of unknowns (e.g. with slow_tac).
  2200 
  2201 *** Simplifier ***
  2202 
  2203 * added interface for simplification procedures (functions that
  2204 produce *proven* rewrite rules on the fly, depending on current
  2205 redex);
  2206 
  2207 * ordering on terms as parameter (used for ordered rewriting);
  2208 
  2209 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2210 
  2211 * the solver is now split into a safe and an unsafe part.
  2212 This should be invisible for the normal user, except that the
  2213 functions setsolver and addsolver have been renamed to setSolver and
  2214 addSolver; added safe_asm_full_simp_tac;
  2215 
  2216 
  2217 *** HOL ***
  2218 
  2219 * a generic induction tactic `induct_tac' which works for all datatypes and
  2220 also for type `nat';
  2221 
  2222 * a generic case distinction tactic `exhaust_tac' which works for all
  2223 datatypes and also for type `nat';
  2224 
  2225 * each datatype comes with a function `size';
  2226 
  2227 * patterns in case expressions allow tuple patterns as arguments to
  2228 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2229 
  2230 * primrec now also works with type nat;
  2231 
  2232 * recdef: a new declaration form, allows general recursive functions to be
  2233 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2234 
  2235 * the constant for negation has been renamed from "not" to "Not" to
  2236 harmonize with FOL, ZF, LK, etc.;
  2237 
  2238 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2239 infinite lists;
  2240 
  2241 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2242 
  2243 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2244 problems in commutative rings, using axiomatic type classes for + and *;
  2245 
  2246 * more examples in HOL/MiniML and HOL/Auth;
  2247 
  2248 * more default rewrite rules for quantifiers, union/intersection;
  2249 
  2250 * a new constant `arbitrary == @x.False';
  2251 
  2252 * HOLCF/IOA replaces old HOL/IOA;
  2253 
  2254 * HOLCF changes: derived all rules and arities
  2255   + axiomatic type classes instead of classes
  2256   + typedef instead of faking type definitions
  2257   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2258   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2259   + eliminated the types void, one, tr
  2260   + use unit lift and bool lift (with translations) instead of one and tr
  2261   + eliminated blift from Lift3.thy (use Def instead of blift)
  2262   all eliminated rules are derived as theorems --> no visible changes ;
  2263 
  2264 
  2265 *** ZF ***
  2266 
  2267 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2268 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2269 as ZF_cs addSIs [equalityI];
  2270 
  2271 
  2272 
  2273 New in Isabelle94-7 (November 96)
  2274 ---------------------------------
  2275 
  2276 * allowing negative levels (as offsets) in prlev and choplev;
  2277 
  2278 * super-linear speedup for large simplifications;
  2279 
  2280 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2281 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2282 FAIL); can suppress it using the command Delsimps (ex_simps @
  2283 all_simps); De Morgan laws are also now included, by default;
  2284 
  2285 * improved printing of ==>  :  ~:
  2286 
  2287 * new object-logic "Sequents" adds linear logic, while replacing LK
  2288 and Modal (thanks to Sara Kalvala);
  2289 
  2290 * HOL/Auth: correctness proofs for authentication protocols;
  2291 
  2292 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2293 examples on HOL/Auth);
  2294 
  2295 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2296 the rewriter and classical reasoner simultaneously;
  2297 
  2298 * function uresult no longer returns theorems in "standard" format;
  2299 regain previous version by: val uresult = standard o uresult;
  2300 
  2301 
  2302 
  2303 New in Isabelle94-6
  2304 -------------------
  2305 
  2306 * oracles -- these establish an interface between Isabelle and trusted
  2307 external reasoners, which may deliver results as theorems;
  2308 
  2309 * proof objects (in particular record all uses of oracles);
  2310 
  2311 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2312 
  2313 * "constdefs" section in theory files;
  2314 
  2315 * "primrec" section (HOL) no longer requires names;
  2316 
  2317 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2318 
  2319 
  2320 
  2321 New in Isabelle94-5
  2322 -------------------
  2323 
  2324 * reduced space requirements;
  2325 
  2326 * automatic HTML generation from theories;
  2327 
  2328 * theory files no longer require "..." (quotes) around most types;
  2329 
  2330 * new examples, including two proofs of the Church-Rosser theorem;
  2331 
  2332 * non-curried (1994) version of HOL is no longer distributed;
  2333 
  2334 
  2335 
  2336 New in Isabelle94-4
  2337 -------------------
  2338 
  2339 * greatly reduced space requirements;
  2340 
  2341 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2342 
  2343 * searchable theorem database (see the section "Retrieving theorems" on
  2344 page 8 of the Reference Manual);
  2345 
  2346 * new examples, including Grabczewski's monumental case study of the
  2347 Axiom of Choice;
  2348 
  2349 * The previous version of HOL renamed to Old_HOL;
  2350 
  2351 * The new version of HOL (previously called CHOL) uses a curried syntax
  2352 for functions.  Application looks like f a b instead of f(a,b);
  2353 
  2354 * Mutually recursive inductive definitions finally work in HOL;
  2355 
  2356 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2357 translates to the operator "split";
  2358 
  2359 
  2360 
  2361 New in Isabelle94-3
  2362 -------------------
  2363 
  2364 * new infix operator, addss, allowing the classical reasoner to
  2365 perform simplification at each step of its search.  Example:
  2366         fast_tac (cs addss ss)
  2367 
  2368 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2369 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2370 look like (a,b) instead of <a,b>;
  2371 
  2372 * PLEASE NOTE: CHOL will eventually replace HOL!
  2373 
  2374 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2375 It translates to the operator "split".  A new theory of integers is available;
  2376 
  2377 * In ZF, integer numerals now denote two's-complement binary integers.
  2378 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2379 
  2380 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2381 of the Axiom of Choice;
  2382 
  2383 
  2384 
  2385 New in Isabelle94-2
  2386 -------------------
  2387 
  2388 * Significantly faster resolution;
  2389 
  2390 * the different sections in a .thy file can now be mixed and repeated
  2391 freely;
  2392 
  2393 * Database of theorems for FOL, HOL and ZF.  New
  2394 commands including qed, qed_goal and bind_thm store theorems in the database.
  2395 
  2396 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2397 a given theory (thms_of), or find out what theory a theorem was proved in
  2398 (theory_of_thm);
  2399 
  2400 * Bugs fixed in the inductive definition and datatype packages;
  2401 
  2402 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2403 and HOL_dup_cs obsolete;
  2404 
  2405 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2406 have been removed;
  2407 
  2408 * Simpler definition of function space in ZF;
  2409 
  2410 * new results about cardinal and ordinal arithmetic in ZF;
  2411 
  2412 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2413 types;
  2414 
  2415 
  2416 $Id$