NEWS
author ballarin
Fri May 09 17:19:58 2003 +0200 (2003-05-09)
changeset 13995 ab988a7a8a3b
parent 13966 2160abf7cfe7
child 14008 f843528b9f3c
permissions -rw-r--r--
NEWS updated for HOL-Algebra.
     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
   152 with implicit structures.  Also a new formalization of ring theory and
   153 and univariate polynomials;
   154 
   155 * GroupTheory: deleted, since its material has been moved to Algebra;
   156 
   157 * Complex: new directory of the complex numbers with numeric constants, 
   158 nonstandard complex numbers, and some complex analysis, standard and 
   159 nonstandard (Jacques Fleuriot);
   160 
   161 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   162 
   163 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   164 Fleuriot);
   165 
   166 * Real/HahnBanach: updated and adapted to locales;
   167 
   168 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   169 Gray and Kramer);
   170 
   171 * UNITY: added the Meier-Sanders theory of progress sets;
   172 
   173 
   174 *** ZF ***
   175 
   176 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   177 universe, etc.);
   178 
   179 * Main ZF: virtually all theories converted to new-style format;
   180 
   181 
   182 *** ML ***
   183 
   184 * Pure: Tactic.prove provides sane interface for internal proofs;
   185 omits the infamous "standard" operation, so this is more appropriate
   186 than prove_goalw_cterm in many situations (e.g. in simprocs);
   187 
   188 * Pure: improved error reporting of simprocs;
   189 
   190 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   191 up simprocs;
   192 
   193 
   194 *** Document preparation ***
   195 
   196 * uses \par instead of \\ for line breaks in theory text. This may
   197 shift some page breaks in large documents. To get the old behaviour
   198 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   199 
   200 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   201 other packages
   202 
   203 * \<euro> now needs package babel/greek instead of marvosym (which
   204 broke \Rightarrow)
   205 
   206 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   207 textcomp package)
   208 
   209 
   210 New in Isabelle2002 (March 2002)
   211 --------------------------------
   212 
   213 *** Document preparation ***
   214 
   215 * greatly simplified document preparation setup, including more
   216 graceful interpretation of isatool usedir -i/-d/-D options, and more
   217 instructive isatool mkdir; users should basically be able to get
   218 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   219 users may run a separate document processing stage manually like this:
   220 "isatool usedir -D output HOL Test && isatool document Test/output";
   221 
   222 * theory dependency graph may now be incorporated into documents;
   223 isatool usedir -g true will produce session_graph.eps/.pdf for use
   224 with \includegraphics of LaTeX;
   225 
   226 * proper spacing of consecutive markup elements, especially text
   227 blocks after section headings;
   228 
   229 * support bold style (for single symbols only), input syntax is like
   230 this: "\<^bold>\<alpha>" or "\<^bold>A";
   231 
   232 * \<bullet> is now output as bold \cdot by default, which looks much
   233 better in printed text;
   234 
   235 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   236 note that these symbols are currently unavailable in Proof General /
   237 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   238 
   239 * isatool latex no longer depends on changed TEXINPUTS, instead
   240 isatool document copies the Isabelle style files to the target
   241 location;
   242 
   243 
   244 *** Isar ***
   245 
   246 * Pure/Provers: improved proof by cases and induction;
   247   - 'case' command admits impromptu naming of parameters (such as
   248     "case (Suc n)");
   249   - 'induct' method divinates rule instantiation from the inductive
   250     claim; no longer requires excessive ?P bindings for proper
   251     instantiation of cases;
   252   - 'induct' method properly enumerates all possibilities of set/type
   253     rules; as a consequence facts may be also passed through *type*
   254     rules without further ado;
   255   - 'induct' method now derives symbolic cases from the *rulified*
   256     rule (before it used to rulify cases stemming from the internal
   257     atomized version); this means that the context of a non-atomic
   258     statement becomes is included in the hypothesis, avoiding the
   259     slightly cumbersome show "PROP ?case" form;
   260   - 'induct' may now use elim-style induction rules without chaining
   261     facts, using ``missing'' premises from the goal state; this allows
   262     rules stemming from inductive sets to be applied in unstructured
   263     scripts, while still benefitting from proper handling of non-atomic
   264     statements; NB: major inductive premises need to be put first, all
   265     the rest of the goal is passed through the induction;
   266   - 'induct' proper support for mutual induction involving non-atomic
   267     rule statements (uses the new concept of simultaneous goals, see
   268     below);
   269   - append all possible rule selections, but only use the first
   270     success (no backtracking);
   271   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   272   - undeclared rule case names default to numbers 1, 2, 3, ...;
   273   - added 'print_induct_rules' (covered by help item in recent Proof
   274     General versions);
   275   - moved induct/cases attributes to Pure, methods to Provers;
   276   - generic method setup instantiated for FOL and HOL;
   277 
   278 * Pure: support multiple simultaneous goal statements, for example
   279 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   280 meta-level mechanism, this acts as if several individual goals had
   281 been stated separately; in particular common proof methods need to be
   282 repeated in order to cover all claims; note that a single elimination
   283 step is *not* sufficient to establish the two conjunctions, so this
   284 fails:
   285 
   286   assume "A & B" then have A and B ..   (*".." fails*)
   287 
   288 better use "obtain" in situations as above; alternative refer to
   289 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   290 
   291 * Pure: proper integration with ``locales''; unlike the original
   292 version by Florian Kammüller, Isar locales package high-level proof
   293 contexts rather than raw logical ones (e.g. we admit to include
   294 attributes everywhere); operations on locales include merge and
   295 rename; support for implicit arguments (``structures''); simultaneous
   296 type-inference over imports and text; see also HOL/ex/Locales.thy for
   297 some examples;
   298 
   299 * Pure: the following commands have been ``localized'', supporting a
   300 target locale specification "(in name)": 'lemma', 'theorem',
   301 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   302 stored both within the locale and at the theory level (exported and
   303 qualified by the locale name);
   304 
   305 * Pure: theory goals may now be specified in ``long'' form, with
   306 ad-hoc contexts consisting of arbitrary locale elements. for example
   307 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   308 definitions may be given, too); the result is a meta-level rule with
   309 the context elements being discharged in the obvious way;
   310 
   311 * Pure: new proof command 'using' allows to augment currently used
   312 facts after a goal statement ('using' is syntactically analogous to
   313 'apply', but acts on the goal's facts only); this allows chained facts
   314 to be separated into parts given before and after a claim, as in
   315 ``from a and b have C using d and e <proof>'';
   316 
   317 * Pure: renamed "antecedent" case to "rule_context";
   318 
   319 * Pure: new 'judgment' command records explicit information about the
   320 object-logic embedding (used by several tools internally); no longer
   321 use hard-wired "Trueprop";
   322 
   323 * Pure: added 'corollary' command;
   324 
   325 * Pure: fixed 'token_translation' command;
   326 
   327 * Pure: removed obsolete 'exported' attribute;
   328 
   329 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   330 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   331 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   332 
   333 * Pure: method 'atomize' presents local goal premises as object-level
   334 statements (atomic meta-level propositions); setup controlled via
   335 rewrite rules declarations of 'atomize' attribute; example
   336 application: 'induct' method with proper rule statements in improper
   337 proof *scripts*;
   338 
   339 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   340 now consider the syntactic context of assumptions, giving a better
   341 chance to get type-inference of the arguments right (this is
   342 especially important for locales);
   343 
   344 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   345 mode;
   346 
   347 * Pure/obtain: the formal conclusion "thesis", being marked as
   348 ``internal'', may no longer be reference directly in the text;
   349 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   350 situations;
   351 
   352 * Pure: generic 'sym' attribute which declares a rule both as pure
   353 'elim?' and for the 'symmetric' operation;
   354 
   355 * Pure: marginal comments ``--'' may now occur just anywhere in the
   356 text; the fixed correlation with particular command syntax has been
   357 discontinued;
   358 
   359 * Pure: new method 'rules' is particularly well-suited for proof
   360 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   361 but often produces more compact proof terms with less detours;
   362 
   363 * Pure/Provers/classical: simplified integration with pure rule
   364 attributes and methods; the classical "intro?/elim?/dest?"
   365 declarations coincide with the pure ones; the "rule" method no longer
   366 includes classically swapped intros; "intro" and "elim" methods no
   367 longer pick rules from the context; also got rid of ML declarations
   368 AddXIs/AddXEs/AddXDs; all of this has some potential for
   369 INCOMPATIBILITY;
   370 
   371 * Provers/classical: attribute 'swapped' produces classical inversions
   372 of introduction rules;
   373 
   374 * Provers/simplifier: 'simplified' attribute may refer to explicit
   375 rules instead of full simplifier context; 'iff' attribute handles
   376 conditional rules;
   377 
   378 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   379 
   380 * HOL: 'recdef' now fails on unfinished automated proofs, use
   381 "(permissive)" option to recover old behavior;
   382 
   383 * HOL: 'inductive' no longer features separate (collective) attributes
   384 for 'intros' (was found too confusing);
   385 
   386 * HOL: properly declared induction rules less_induct and
   387 wf_induct_rule;
   388 
   389 
   390 *** HOL ***
   391 
   392 * HOL: moved over to sane numeral syntax; the new policy is as
   393 follows:
   394 
   395   - 0 and 1 are polymorphic constants, which are defined on any
   396   numeric type (nat, int, real etc.);
   397 
   398   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   399   binary representation internally;
   400 
   401   - type nat has special constructor Suc, and generally prefers Suc 0
   402   over 1::nat and Suc (Suc 0) over 2::nat;
   403 
   404 This change may cause significant problems of INCOMPATIBILITY; here
   405 are some hints on converting existing sources:
   406 
   407   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   408   entities, so expressions involving "-" (unary or binary minus) need
   409   to be spaced properly;
   410 
   411   - existing occurrences of "1" may need to be constraint "1::nat" or
   412   even replaced by Suc 0; similar for old "2";
   413 
   414   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   415 
   416   - remove all special provisions on numerals in proofs;
   417 
   418 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   419 representation (depends on bin_arith_simps in the default context);
   420 
   421 * HOL: symbolic syntax for x^2 (numeral 2);
   422 
   423 * HOL: the class of all HOL types is now called "type" rather than
   424 "term"; INCOMPATIBILITY, need to adapt references to this type class
   425 in axclass/classes, instance/arities, and (usually rare) occurrences
   426 in typings (of consts etc.); internally the class is called
   427 "HOL.type", ML programs should refer to HOLogic.typeS;
   428 
   429 * HOL/record package improvements:
   430   - new derived operations "fields" to build a partial record section,
   431     "extend" to promote a fixed record to a record scheme, and
   432     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   433     declared as simp by default;
   434   - shared operations ("more", "fields", etc.) now need to be always
   435     qualified) --- potential INCOMPATIBILITY;
   436   - removed "make_scheme" operations (use "make" with "extend") --
   437     INCOMPATIBILITY;
   438   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   439   - provides cases/induct rules for use with corresponding Isar
   440     methods (for concrete records, record schemes, concrete more
   441     parts, and schematic more parts -- in that order);
   442   - internal definitions directly based on a light-weight abstract
   443     theory of product types over typedef rather than datatype;
   444 
   445 * HOL: generic code generator for generating executable ML code from
   446 specifications; specific support for HOL constructs such as inductive
   447 datatypes and sets, as well as recursive functions; can be invoked
   448 via 'generate_code' theory section;
   449 
   450 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   451 
   452 * HOL: consolidated and renamed several theories.  In particular:
   453 	Ord.thy has been absorbed into HOL.thy
   454 	String.thy has been absorbed into List.thy
   455  
   456 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   457 (beware of argument permutation!);
   458 
   459 * HOL: linorder_less_split superseded by linorder_cases;
   460 
   461 * HOL/List: "nodups" renamed to "distinct";
   462 
   463 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   464 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   465   - Ex_def has changed, now need to use some_eq_ex
   466 
   467 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   468 in this (rare) case use:
   469 
   470   delSWrapper "split_all_tac"
   471   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   472 
   473 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   474 MAY FAIL;
   475 
   476 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   477 Isabelle's type classes, ^ on functions and relations has too general
   478 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   479 necessary to attach explicit type constraints;
   480 
   481 * HOL/Relation: the prefix name of the infix "O" has been changed from
   482 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   483 renamed accordingly (eg "compI" -> "rel_compI").
   484 
   485 * HOL: syntax translations now work properly with numerals and records
   486 expressions;
   487 
   488 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   489 of "lam" -- INCOMPATIBILITY;
   490 
   491 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   492 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   493 renamed "Product_Type.unit";
   494 
   495 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   496 
   497 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   498 the "cases" method);
   499 
   500 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   501 Florian Kammüller);
   502 
   503 * HOL/IMP: updated and converted to new-style theory format; several
   504 parts turned into readable document, with proper Isar proof texts and
   505 some explanations (by Gerwin Klein);
   506 
   507 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   508 
   509 * HOL-Hyperreal is now a logic image;
   510 
   511 
   512 *** HOLCF ***
   513 
   514 * Isar: consts/constdefs supports mixfix syntax for continuous
   515 operations;
   516 
   517 * Isar: domain package adapted to new-style theory format, e.g. see
   518 HOLCF/ex/Dnat.thy;
   519 
   520 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   521 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   522 lift.induct_tac, always use UU instead of Undef;
   523 
   524 * HOLCF/IMP: updated and converted to new-style theory;
   525 
   526 
   527 *** ZF ***
   528 
   529 * Isar: proper integration of logic-specific tools and packages,
   530 including theory commands '(co)inductive', '(co)datatype',
   531 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   532 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   533 
   534 * theory Main no longer includes AC; for the Axiom of Choice, base
   535 your theory on Main_ZFC;
   536 
   537 * the integer library now covers quotients and remainders, with many
   538 laws relating division to addition, multiplication, etc.;
   539 
   540 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   541 typeless version of the formalism;
   542 
   543 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   544 format;
   545 
   546 * ZF/Induct: new directory for examples of inductive definitions,
   547 including theory Multiset for multiset orderings; converted to
   548 new-style theory format;
   549 
   550 * ZF: many new theorems about lists, ordinals, etc.;
   551 
   552 
   553 *** General ***
   554 
   555 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   556 variable proof controls level of detail: 0 = no proofs (only oracle
   557 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   558 also ref manual for further ML interfaces;
   559 
   560 * Pure/axclass: removed obsolete ML interface
   561 goal_subclass/goal_arity;
   562 
   563 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   564 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   565 separate tokens, so expressions involving minus need to be spaced
   566 properly;
   567 
   568 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   569 rather than "infixl" or "infixr";
   570 
   571 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   572 sort constraint specifications in type inference; e.g. "x::_::foo"
   573 ensures that the type of "x" is of sort "foo" (but not necessarily a
   574 type variable);
   575 
   576 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   577 control output of nested => (types); the default behavior is
   578 "type_brackets";
   579 
   580 * Pure/syntax: builtin parse translation for "_constify" turns valued
   581 tokens into AST constants;
   582 
   583 * Pure/syntax: prefer later declarations of translations and print
   584 translation functions; potential INCOMPATIBILITY: need to reverse
   585 multiple declarations for same syntax element constant;
   586 
   587 * Pure/show_hyps reset by default (in accordance to existing Isar
   588 practice);
   589 
   590 * Provers/classical: renamed addaltern to addafter, addSaltern to
   591 addSafter;
   592 
   593 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   594 as well;
   595 
   596 * system: tested support for MacOS X; should be able to get Isabelle +
   597 Proof General to work in a plain Terminal after installing Poly/ML
   598 (e.g. from the Isabelle distribution area) and GNU bash alone
   599 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   600 support requires further installations, e.g. from
   601 http://fink.sourceforge.net/);
   602 
   603 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   604 
   605 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   606 of 40 MB), cf. ML_OPTIONS;
   607 
   608 * system: Proof General keywords specification is now part of the
   609 Isabelle distribution (see etc/isar-keywords.el);
   610 
   611 * system: support for persistent Proof General sessions (refrain from
   612 outdating all loaded theories on startup); user may create writable
   613 logic images like this: ``isabelle -q HOL Test'';
   614 
   615 * system: smart selection of Isabelle process versus Isabelle
   616 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   617 run both "isabelle" and "Isabelle" even if file names are badly
   618 damaged (executable inspects the case of the first letter of its own
   619 name); added separate "isabelle-process" and "isabelle-interface";
   620 
   621 * system: refrain from any attempt at filtering input streams; no
   622 longer support ``8bit'' encoding of old isabelle font, instead proper
   623 iso-latin characters may now be used; the related isatools
   624 "symbolinput" and "nonascii" have disappeared as well;
   625 
   626 * system: removed old "xterm" interface (the print modes "xterm" and
   627 "xterm_color" are still available for direct use in a suitable
   628 terminal);
   629 
   630 
   631 
   632 New in Isabelle99-2 (February 2001)
   633 -----------------------------------
   634 
   635 *** Overview of INCOMPATIBILITIES ***
   636 
   637 * HOL: please note that theories in the Library and elsewhere often use the
   638 new-style (Isar) format; to refer to their theorems in an ML script you must
   639 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   640 
   641 * HOL: inductive package no longer splits induction rule aggressively,
   642 but only as far as specified by the introductions given; the old
   643 format may be recovered via ML function complete_split_rule or attribute
   644 'split_rule (complete)';
   645 
   646 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   647 gfp_Tarski to gfp_unfold;
   648 
   649 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   650 
   651 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   652 relation); infix "^^" has been renamed "``"; infix "``" has been
   653 renamed "`"; "univalent" has been renamed "single_valued";
   654 
   655 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   656 operation;
   657 
   658 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   659 
   660 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   661 
   662 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   663 consequence, it is no longer monotonic wrt. the local goal context
   664 (which is now passed through the inductive cases);
   665 
   666 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   667 \<gg> to \<ggreater>;
   668 
   669 
   670 *** Document preparation ***
   671 
   672 * \isabellestyle{NAME} selects version of Isabelle output (currently
   673 available: are "it" for near math-mode best-style output, "sl" for
   674 slanted text style, and "tt" for plain type-writer; if no
   675 \isabellestyle command is given, output is according to slanted
   676 type-writer);
   677 
   678 * support sub/super scripts (for single symbols only), input syntax is
   679 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   680 
   681 * some more standard symbols; see Appendix A of the system manual for
   682 the complete list of symbols defined in isabellesym.sty;
   683 
   684 * improved isabelle style files; more abstract symbol implementation
   685 (should now use \isamath{...} and \isatext{...} in custom symbol
   686 definitions);
   687 
   688 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   689 state; Note that presentation of goal states does not conform to
   690 actual human-readable proof documents.  Please do not include goal
   691 states into document output unless you really know what you are doing!
   692 
   693 * proper indentation of antiquoted output with proportional LaTeX
   694 fonts;
   695 
   696 * no_document ML operator temporarily disables LaTeX document
   697 generation;
   698 
   699 * isatool unsymbolize tunes sources for plain ASCII communication;
   700 
   701 
   702 *** Isar ***
   703 
   704 * Pure: Isar now suffers initial goal statements to contain unbound
   705 schematic variables (this does not conform to actual readable proof
   706 documents, due to unpredictable outcome and non-compositional proof
   707 checking); users who know what they are doing may use schematic goals
   708 for Prolog-style synthesis of proven results;
   709 
   710 * Pure: assumption method (an implicit finishing) now handles actual
   711 rules as well;
   712 
   713 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   714 initial goal, declare "that" only as Pure intro (only for single
   715 steps); the "that" rule assumption may now be involved in implicit
   716 finishing, thus ".." becomes a feasible for trivial obtains;
   717 
   718 * Pure: default proof step now includes 'intro_classes'; thus trivial
   719 instance proofs may be performed by "..";
   720 
   721 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   722 statements as well;
   723 
   724 * Pure: more robust selection of calculational rules;
   725 
   726 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   727 rule (as well as the assumption rule);
   728 
   729 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   730 lemmas, using the graph browser tool;
   731 
   732 * Pure: predict failure of "show" in interactive mode;
   733 
   734 * Pure: 'thms_containing' now takes actual terms as arguments;
   735 
   736 * HOL: improved method 'induct' --- now handles non-atomic goals
   737 (potential INCOMPATIBILITY); tuned error handling;
   738 
   739 * HOL: cases and induct rules now provide explicit hints about the
   740 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   741 any remaining facts are inserted into the goal verbatim;
   742 
   743 * HOL: local contexts (aka cases) may now contain term bindings as
   744 well; the 'cases' and 'induct' methods new provide a ?case binding for
   745 the result to be shown in each case;
   746 
   747 * HOL: added 'recdef_tc' command;
   748 
   749 * isatool convert assists in eliminating legacy ML scripts;
   750 
   751 
   752 *** HOL ***
   753 
   754 * HOL/Library: a collection of generic theories to be used together
   755 with main HOL; the theory loader path already includes this directory
   756 by default; the following existing theories have been moved here:
   757 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   758 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   759 
   760 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   761 modelling and verification task performed in Isabelle/HOL +
   762 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   763 
   764 * HOL/Algebra: special summation operator SUM no longer exists, it has
   765 been replaced by setsum; infix 'assoc' now has priority 50 (like
   766 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   767 'domain', this makes the theory consistent with mathematical
   768 literature;
   769 
   770 * HOL basics: added overloaded operations "inverse" and "divide"
   771 (infix "/"), syntax for generic "abs" operation, generic summation
   772 operator \<Sum>;
   773 
   774 * HOL/typedef: simplified package, provide more useful rules (see also
   775 HOL/subset.thy);
   776 
   777 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   778 now expressed as a proper nested rule (old-style tactic scripts may
   779 require atomize_strip_tac to cope with non-atomic premises);
   780 
   781 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   782 to "split_conv" (old name still available for compatibility);
   783 
   784 * HOL: improved concrete syntax for strings (e.g. allows translation
   785 rules with string literals);
   786 
   787 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   788  and Fleuriot's mechanization of analysis, including the transcendental
   789  functions for the reals;
   790 
   791 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   792 
   793 
   794 *** CTT ***
   795 
   796 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   797 "lam" is displayed as TWO lambda-symbols
   798 
   799 * CTT: theory Main now available, containing everything (that is, Bool
   800 and Arith);
   801 
   802 
   803 *** General ***
   804 
   805 * Pure: the Simplifier has been implemented properly as a derived rule
   806 outside of the actual kernel (at last!); the overall performance
   807 penalty in practical applications is about 50%, while reliability of
   808 the Isabelle inference kernel has been greatly improved;
   809 
   810 * print modes "brackets" and "no_brackets" control output of nested =>
   811 (types) and ==> (props); the default behaviour is "brackets";
   812 
   813 * Provers: fast_tac (and friends) now handle actual object-logic rules
   814 as assumptions as well;
   815 
   816 * system: support Poly/ML 4.0;
   817 
   818 * system: isatool install handles KDE version 1 or 2;
   819 
   820 
   821 
   822 New in Isabelle99-1 (October 2000)
   823 ----------------------------------
   824 
   825 *** Overview of INCOMPATIBILITIES ***
   826 
   827 * HOL: simplification of natural numbers is much changed; to partly
   828 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   829 issue the following ML commands:
   830 
   831   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   832   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   833 
   834 * HOL: simplification no longer dives into case-expressions; this is
   835 controlled by "t.weak_case_cong" for each datatype t;
   836 
   837 * HOL: nat_less_induct renamed to less_induct;
   838 
   839 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   840 fixsome to patch .thy and .ML sources automatically;
   841 
   842   select_equality  -> some_equality
   843   select_eq_Ex     -> some_eq_ex
   844   selectI2EX       -> someI2_ex
   845   selectI2         -> someI2
   846   selectI          -> someI
   847   select1_equality -> some1_equality
   848   Eps_sym_eq       -> some_sym_eq_trivial
   849   Eps_eq           -> some_eq_trivial
   850 
   851 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   852 
   853 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   854 instead);
   855 
   856 * HOL: the recursion equations generated by 'recdef' are now called
   857 f.simps instead of f.rules;
   858 
   859 * HOL: qed_spec_mp now also handles bounded ALL as well;
   860 
   861 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   862 sometimes be needed;
   863 
   864 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   865 
   866 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   867 
   868 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   869 product is now "<*>" instead of "Times"; the lexicographic product is
   870 now "<*lex*>" instead of "**";
   871 
   872 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   873 of main HOL, but was unused); better use HOL's datatype package;
   874 
   875 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   876 the old syntax may be recovered as follows:
   877 
   878   syntax (symbols)
   879     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   880       (infixl "\\<oplus>" 100)
   881 
   882 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   883 
   884 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   885 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   886 internally;
   887 
   888 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   889 changed from A/r to A//r;
   890 
   891 * ZF: new treatment of arithmetic (nat & int) may break some old
   892 proofs;
   893 
   894 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   895 rulify -> rule_format, elimify -> elim_format, ...);
   896 
   897 * Isar/Provers: intro/elim/dest attributes changed; renamed
   898 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   899 should have to change intro!! to intro? only); replaced "delrule" by
   900 "rule del";
   901 
   902 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   903 
   904 * Provers: strengthened force_tac by using new first_best_tac;
   905 
   906 * LaTeX document preparation: several changes of isabelle.sty (see
   907 lib/texinputs);
   908 
   909 
   910 *** Document preparation ***
   911 
   912 * formal comments (text blocks etc.) in new-style theories may now
   913 contain antiquotations of thm/prop/term/typ/text to be presented
   914 according to latex print mode; concrete syntax is like this:
   915 @{term[show_types] "f(x) = a + x"};
   916 
   917 * isatool mkdir provides easy setup of Isabelle session directories,
   918 including proper document sources;
   919 
   920 * generated LaTeX sources are now deleted after successful run
   921 (isatool document -c); may retain a copy somewhere else via -D option
   922 of isatool usedir;
   923 
   924 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   925 style files, achieving self-contained LaTeX sources and simplifying
   926 LaTeX debugging;
   927 
   928 * old-style theories now produce (crude) LaTeX output as well;
   929 
   930 * browser info session directories are now self-contained (may be put
   931 on WWW server seperately); improved graphs of nested sessions; removed
   932 graph for 'all sessions';
   933 
   934 * several improvements in isabelle style files; \isabellestyle{it}
   935 produces fake math mode output; \isamarkupheader is now \section by
   936 default; see lib/texinputs/isabelle.sty etc.;
   937 
   938 
   939 *** Isar ***
   940 
   941 * Isar/Pure: local results and corresponding term bindings are now
   942 subject to Hindley-Milner polymorphism (similar to ML); this
   943 accommodates incremental type-inference very nicely;
   944 
   945 * Isar/Pure: new derived language element 'obtain' supports
   946 generalized existence reasoning;
   947 
   948 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   949 support accumulation of results, without applying any rules yet;
   950 useful to collect intermediate results without explicit name
   951 references, and for use with transitivity rules with more than 2
   952 premises;
   953 
   954 * Isar/Pure: scalable support for case-analysis type proofs: new
   955 'case' language element refers to local contexts symbolically, as
   956 produced by certain proof methods; internally, case names are attached
   957 to theorems as "tags";
   958 
   959 * Isar/Pure: theory command 'hide' removes declarations from
   960 class/type/const name spaces;
   961 
   962 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   963 indicate potential overloading;
   964 
   965 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   966 
   967 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   968 "{a,b,c}" instead of {a,b,c};
   969 
   970 * Isar/Pure now provides its own version of intro/elim/dest
   971 attributes; useful for building new logics, but beware of confusion
   972 with the version in Provers/classical;
   973 
   974 * Isar/Pure: the local context of (non-atomic) goals is provided via
   975 case name 'antecedent';
   976 
   977 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   978 to the current context is now done automatically);
   979 
   980 * Isar/Pure: theory command 'method_setup' provides a simple interface
   981 for definining proof methods in ML;
   982 
   983 * Isar/Provers: intro/elim/dest attributes changed; renamed
   984 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   985 most cases, one should have to change intro!! to intro? only);
   986 replaced "delrule" by "rule del";
   987 
   988 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   989 'symmetric' attribute (the latter supercedes [RS sym]);
   990 
   991 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   992 method modifier); 'simp' method: 'only:' modifier removes loopers as
   993 well (including splits);
   994 
   995 * Isar/Provers: Simplifier and Classical methods now support all kind
   996 of modifiers used in the past, including 'cong', 'iff', etc.
   997 
   998 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   999 of Simplifier and Classical reasoner);
  1000 
  1001 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1002 now support named cases; major packages (inductive, datatype, primrec,
  1003 recdef) support case names and properly name parameters;
  1004 
  1005 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1006 monotonicity conditions are extracted to be proven at end of
  1007 calculations;
  1008 
  1009 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1010 method anyway;
  1011 
  1012 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1013 split_if split_if_asm; datatype package provides theorems foo.splits =
  1014 foo.split foo.split_asm for each datatype;
  1015 
  1016 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1017 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1018 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1019 use "(cases (simplified))" method in proper proof texts);
  1020 
  1021 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1022 
  1023 * Isar: names of theorems etc. may be natural numbers as well;
  1024 
  1025 * Isar: 'pr' command: optional arguments for goals_limit and
  1026 ProofContext.prems_limit; no longer prints theory contexts, but only
  1027 proof states;
  1028 
  1029 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1030 additional print modes to be specified; e.g. "pr(latex)" will print
  1031 proof state according to the Isabelle LaTeX style;
  1032 
  1033 * Isar: improved support for emulating tactic scripts, including proof
  1034 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1035 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1036 (for HOL datatypes);
  1037 
  1038 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1039 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1040 'proof method scripts' have to be in depth-first order;
  1041 
  1042 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1043 
  1044 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1045 should instead use individual commands for printing items
  1046 (print_commands, print_methods etc.);
  1047 
  1048 * Isar: added 'nothing' --- the empty list of theorems;
  1049 
  1050 
  1051 *** HOL ***
  1052 
  1053 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1054 corresponding virtual machine and a specification of its bytecode
  1055 verifier and a lightweight bytecode verifier, including proofs of
  1056 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1057 Cornelia Pusch (see also the homepage of project Bali at
  1058 http://isabelle.in.tum.de/Bali/);
  1059 
  1060 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1061 Clemens Ballarin;
  1062 
  1063 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1064 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1065 Rasmussen;
  1066 
  1067 * HOL/Lattice: fundamental concepts of lattice theory and order
  1068 structures, including duals, properties of bounds versus algebraic
  1069 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1070 Theorem for complete lattices etc.; may also serve as a demonstration
  1071 for abstract algebraic reasoning using axiomatic type classes, and
  1072 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1073 
  1074 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1075 von Oheimb;
  1076 
  1077 * HOL/IMPP: extension of IMP with local variables and mutually
  1078 recursive procedures, by David von Oheimb;
  1079 
  1080 * HOL/Lambda: converted into new-style theory and document;
  1081 
  1082 * HOL/ex/Multiquote: example of multiple nested quotations and
  1083 anti-quotations -- basically a generalized version of de-Bruijn
  1084 representation; very useful in avoiding lifting of operations;
  1085 
  1086 * HOL/record: added general record equality rule to simpset; fixed
  1087 select-update simplification procedure to handle extended records as
  1088 well; admit "r" as field name;
  1089 
  1090 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1091 other numeric types and also as the identity of groups, rings, etc.;
  1092 
  1093 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1094 Types nat and int belong to this axclass;
  1095 
  1096 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1097    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1098    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1099   two terms #m*u and #n*u are replaced by #(m+n)*u
  1100     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1101   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1102     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1103 
  1104 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1105 powerful prover for predicate logic but knows nothing of clasets; see
  1106 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1107 
  1108 * HOL: new version of "case_tac" subsumes both boolean case split and
  1109 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1110 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1111 
  1112 * HOL: simplification no longer dives into case-expressions: only the
  1113 selector expression is simplified, but not the remaining arms; to
  1114 enable full simplification of case-expressions for datatype t, you may
  1115 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1116 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1117 
  1118 * HOL/recdef: the recursion equations generated by 'recdef' for
  1119 function 'f' are now called f.simps instead of f.rules; if all
  1120 termination conditions are proved automatically, these simplification
  1121 rules are added to the simpset, as in primrec; rules may be named
  1122 individually as well, resulting in a separate list of theorems for
  1123 each equation;
  1124 
  1125 * HOL/While is a new theory that provides a while-combinator. It
  1126 permits the definition of tail-recursive functions without the
  1127 provision of a termination measure. The latter is necessary once the
  1128 invariant proof rule for while is applied.
  1129 
  1130 * HOL: new (overloaded) notation for the set of elements below/above
  1131 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1132 
  1133 * HOL: theorems impI, allI, ballI bound as "strip";
  1134 
  1135 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1136 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1137 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1138 
  1139 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1140 
  1141 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1142 main HOL, but was unused);
  1143 
  1144 * HOL: fewer consts declared as global (e.g. have to refer to
  1145 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1146 
  1147 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1148 in case of overlap with user translations (e.g. judgements over
  1149 tuples); (note that the underlying logical represenation is still
  1150 bogus);
  1151 
  1152 
  1153 *** ZF ***
  1154 
  1155 * ZF: simplification automatically cancels common terms in arithmetic
  1156 expressions over nat and int;
  1157 
  1158 * ZF: new treatment of nat to minimize type-checking: all operators
  1159 coerce their operands to a natural number using the function natify,
  1160 making the algebraic laws unconditional;
  1161 
  1162 * ZF: as above, for int: operators coerce their operands to an integer
  1163 using the function intify;
  1164 
  1165 * ZF: the integer library now contains many of the usual laws for the
  1166 orderings, including $<=, and monotonicity laws for $+ and $*;
  1167 
  1168 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1169 simplification;
  1170 
  1171 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1172 to the simplifier and classical reasoner simultaneously;
  1173 
  1174 
  1175 *** General ***
  1176 
  1177 * Provers: blast_tac now handles actual object-logic rules as
  1178 assumptions; note that auto_tac uses blast_tac internally as well;
  1179 
  1180 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1181 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1182 
  1183 * Provers: delrules now handles destruct rules as well (no longer need
  1184 explicit make_elim);
  1185 
  1186 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1187   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1188 use instead the strong form,
  1189   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1190 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1191 from destruct-rules;
  1192 
  1193 * Provers: Simplifier.easy_setup provides a fast path to basic
  1194 Simplifier setup for new object-logics;
  1195 
  1196 * Pure: AST translation rules no longer require constant head on LHS;
  1197 
  1198 * Pure: improved name spaces: ambiguous output is qualified; support
  1199 for hiding of names;
  1200 
  1201 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1202 XSYMBOL_HOME; no longer need to do manual configuration in most
  1203 situations;
  1204 
  1205 * system: compression of ML heaps images may now be controlled via -c
  1206 option of isabelle and isatool usedir (currently only observed by
  1207 Poly/ML);
  1208 
  1209 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1210 useful for remote X11);
  1211 
  1212 * system: provide TAGS file for Isabelle sources;
  1213 
  1214 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1215 order;
  1216 
  1217 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1218 timing flag supersedes proof_timing and Toplevel.trace;
  1219 
  1220 * ML: new combinators |>> and |>>> for incremental transformations
  1221 with secondary results (e.g. certain theory extensions):
  1222 
  1223 * ML: PureThy.add_defs gets additional argument to indicate potential
  1224 overloading (usually false);
  1225 
  1226 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1227 results;
  1228 
  1229 
  1230 
  1231 New in Isabelle99 (October 1999)
  1232 --------------------------------
  1233 
  1234 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1235 
  1236 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1237 are no longer simplified.  (This allows the simplifier to unfold recursive
  1238 functional programs.)  To restore the old behaviour, declare
  1239 
  1240     Delcongs [if_weak_cong];
  1241 
  1242 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1243 complement;
  1244 
  1245 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1246 
  1247 * HOL/datatype: mutual_induct_tac no longer exists --
  1248   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1249 
  1250 * HOL/typedef: fixed type inference for representing set; type
  1251 arguments now have to occur explicitly on the rhs as type constraints;
  1252 
  1253 * ZF: The con_defs part of an inductive definition may no longer refer
  1254 to constants declared in the same theory;
  1255 
  1256 * HOL, ZF: the function mk_cases, generated by the inductive
  1257 definition package, has lost an argument.  To simplify its result, it
  1258 uses the default simpset instead of a supplied list of theorems.
  1259 
  1260 * HOL/List: the constructors of type list are now Nil and Cons;
  1261 
  1262 * Simplifier: the type of the infix ML functions
  1263         setSSolver addSSolver setSolver addSolver
  1264 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1265 for packaging solvers. A solver is created via
  1266         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1267 where the string argument is only a comment.
  1268 
  1269 
  1270 *** Proof tools ***
  1271 
  1272 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1273 decision procedure for linear arithmetic. Currently it is used for
  1274 types `nat', `int', and `real' in HOL (see below); it can, should and
  1275 will be instantiated for other types and logics as well.
  1276 
  1277 * The simplifier now accepts rewrite rules with flexible heads, eg
  1278      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1279   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1280   matching.
  1281 
  1282 
  1283 *** General ***
  1284 
  1285 * New Isabelle/Isar subsystem provides an alternative to traditional
  1286 tactical theorem proving; together with the ProofGeneral/isar user
  1287 interface it offers an interactive environment for developing human
  1288 readable proof documents (Isar == Intelligible semi-automated
  1289 reasoning); for further information see isatool doc isar-ref,
  1290 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1291 
  1292 * improved and simplified presentation of theories: better HTML markup
  1293 (including colors), graph views in several sizes; isatool usedir now
  1294 provides a proper interface for user theories (via -P option); actual
  1295 document preparation based on (PDF)LaTeX is available as well (for
  1296 new-style theories only); see isatool doc system for more information;
  1297 
  1298 * native support for Proof General, both for classic Isabelle and
  1299 Isabelle/Isar;
  1300 
  1301 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1302 using the graph browser tool;
  1303 
  1304 * Isabelle manuals now also available as PDF;
  1305 
  1306 * theory loader rewritten from scratch (may not be fully
  1307 bug-compatible); old loadpath variable has been replaced by show_path,
  1308 add_path, del_path, reset_path functions; new operations such as
  1309 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1310 isatool doc ref);
  1311 
  1312 * improved isatool install: option -k creates KDE application icon,
  1313 option -p DIR installs standalone binaries;
  1314 
  1315 * added ML_PLATFORM setting (useful for cross-platform installations);
  1316 more robust handling of platform specific ML images for SML/NJ;
  1317 
  1318 * the settings environment is now statically scoped, i.e. it is never
  1319 created again in sub-processes invoked from isabelle, isatool, or
  1320 Isabelle;
  1321 
  1322 * path element specification '~~' refers to '$ISABELLE_HOME';
  1323 
  1324 * in locales, the "assumes" and "defines" parts may be omitted if
  1325 empty;
  1326 
  1327 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1328 long arrows);
  1329 
  1330 * new print_mode "HTML";
  1331 
  1332 * new flag show_tags controls display of tags of theorems (which are
  1333 basically just comments that may be attached by some tools);
  1334 
  1335 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1336 mode and goal output format:
  1337 
  1338 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1339 244c244
  1340 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1341 ---
  1342 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1343 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1344 181c181
  1345 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1346 ---
  1347 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1348 
  1349 * function bind_thms stores lists of theorems (cf. bind_thm);
  1350 
  1351 * new shorthand tactics ftac, eatac, datac, fatac;
  1352 
  1353 * qed (and friends) now accept "" as result name; in that case the
  1354 theorem is not stored, but proper checks and presentation of the
  1355 result still apply;
  1356 
  1357 * theorem database now also indexes constants "Trueprop", "all",
  1358 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1359 
  1360 
  1361 *** HOL ***
  1362 
  1363 ** HOL arithmetic **
  1364 
  1365 * There are now decision procedures for linear arithmetic over nat and
  1366 int:
  1367 
  1368 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1369 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1370 are treated as atomic; subformulae not involving type `nat' or `int'
  1371 are ignored; quantified subformulae are ignored unless they are
  1372 positive universal or negative existential. The tactic has to be
  1373 invoked by hand and can be a little bit slow. In particular, the
  1374 running time is exponential in the number of occurrences of `min' and
  1375 `max', and `-' on `nat'.
  1376 
  1377 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1378 (negated) (in)equalities among the premises and the conclusion into
  1379 account (i.e. no compound formulae) and does not know about `min' and
  1380 `max', and `-' on `nat'. It is fast and is used automatically by the
  1381 simplifier.
  1382 
  1383 NB: At the moment, these decision procedures do not cope with mixed
  1384 nat/int formulae where the two parts interact, such as `m < n ==>
  1385 int(m) < int(n)'.
  1386 
  1387 * HOL/Numeral provides a generic theory of numerals (encoded
  1388 efficiently as bit strings); setup for types nat/int/real is in place;
  1389 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1390 int, existing theories and proof scripts may require a few additional
  1391 type constraints;
  1392 
  1393 * integer division and remainder can now be performed on constant
  1394 arguments;
  1395 
  1396 * many properties of integer multiplication, division and remainder
  1397 are now available;
  1398 
  1399 * An interface to the Stanford Validity Checker (SVC) is available through the
  1400 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1401 are proved automatically.  SVC must be installed separately, and its results
  1402 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1403 invocation of the underlying oracle).  For SVC see
  1404   http://verify.stanford.edu/SVC
  1405 
  1406 * IsaMakefile: the HOL-Real target now builds an actual image;
  1407 
  1408 
  1409 ** HOL misc **
  1410 
  1411 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1412 (in Isabelle/Isar) -- by Gertrud Bauer;
  1413 
  1414 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1415 analysis for assembly languages with subtypes;
  1416 
  1417 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1418 -- avoids syntactic ambiguities and treats state, transition, and
  1419 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1420 changed syntax and (many) tactics;
  1421 
  1422 * HOL/inductive: Now also handles more general introduction rules such
  1423   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1424   theorems are now maintained within the theory (maintained via the
  1425   "mono" attribute);
  1426 
  1427 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1428   (using function types) such as
  1429 
  1430   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1431 
  1432 * HOL/record: record_simproc (part of the default simpset) takes care
  1433 of selectors applied to updated records; record_split_tac is no longer
  1434 part of the default claset; update_defs may now be removed from the
  1435 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1436 
  1437   claset_ref () := claset() addSWrapper record_split_wrapper;
  1438   Delsimprocs [record_simproc]
  1439 
  1440 * HOL/typedef: fixed type inference for representing set; type
  1441 arguments now have to occur explicitly on the rhs as type constraints;
  1442 
  1443 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1444 names rather than an ML expression;
  1445 
  1446 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1447 supplied later.  Program schemes can be defined, such as
  1448     "While B C s = (if B s then While B C (C s) else s)"
  1449 where the well-founded relation can be chosen after B and C have been given.
  1450 
  1451 * HOL/List: the constructors of type list are now Nil and Cons;
  1452 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1453 course, ML tools referring to List.list.op # etc. have to be adapted;
  1454 
  1455 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1456 disabled by default; run isabelle with option -m HOL to get back to
  1457 the original Gordon/HOL-style output;
  1458 
  1459 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1460 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1461 
  1462 * HOL basic syntax simplified (more orthogonal): all variants of
  1463 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1464 Eps operator is provided as well: "SOME x. P[x]";
  1465 
  1466 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1467 
  1468 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1469 thus available for user theories;
  1470 
  1471 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1472 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1473 time;
  1474 
  1475 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1476 several times and then mp;
  1477 
  1478 
  1479 *** LK ***
  1480 
  1481 * the notation <<...>> is now available as a notation for sequences of
  1482 formulas;
  1483 
  1484 * the simplifier is now installed
  1485 
  1486 * the axiom system has been generalized (thanks to Soren Heilmann)
  1487 
  1488 * the classical reasoner now has a default rule database
  1489 
  1490 
  1491 *** ZF ***
  1492 
  1493 * new primrec section allows primitive recursive functions to be given
  1494 directly (as in HOL) over datatypes and the natural numbers;
  1495 
  1496 * new tactics induct_tac and exhaust_tac for induction (or case
  1497 analysis) over datatypes and the natural numbers;
  1498 
  1499 * the datatype declaration of type T now defines the recursor T_rec;
  1500 
  1501 * simplification automatically does freeness reasoning for datatype
  1502 constructors;
  1503 
  1504 * automatic type-inference, with AddTCs command to insert new
  1505 type-checking rules;
  1506 
  1507 * datatype introduction rules are now added as Safe Introduction rules
  1508 to the claset;
  1509 
  1510 * the syntax "if P then x else y" is now available in addition to
  1511 if(P,x,y);
  1512 
  1513 
  1514 *** Internal programming interfaces ***
  1515 
  1516 * tuned simplifier trace output; new flag debug_simp;
  1517 
  1518 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1519 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1520 
  1521 * AxClass.axclass_tac lost the theory argument;
  1522 
  1523 * tuned current_goals_markers semantics: begin / end goal avoids
  1524 printing empty lines;
  1525 
  1526 * removed prs and prs_fn hook, which was broken because it did not
  1527 include \n in its semantics, forcing writeln to add one
  1528 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1529 string -> unit if you really want to output text without newline;
  1530 
  1531 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1532 plain output, interface builders may have to enable 'isabelle_font'
  1533 mode to get Isabelle font glyphs as before;
  1534 
  1535 * refined token_translation interface; INCOMPATIBILITY: output length
  1536 now of type real instead of int;
  1537 
  1538 * theory loader actions may be traced via new ThyInfo.add_hook
  1539 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1540 your own database of information attached to *whole* theories -- as
  1541 opposed to intra-theory data slots offered via TheoryDataFun;
  1542 
  1543 * proper handling of dangling sort hypotheses (at last!);
  1544 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1545 extra sort hypotheses that can be witnessed from the type signature;
  1546 the force_strip_shyps flag is gone, any remaining shyps are simply
  1547 left in the theorem (with a warning issued by strip_shyps_warning);
  1548 
  1549 
  1550 
  1551 New in Isabelle98-1 (October 1998)
  1552 ----------------------------------
  1553 
  1554 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1555 
  1556 * several changes of automated proof tools;
  1557 
  1558 * HOL: major changes to the inductive and datatype packages, including
  1559 some minor incompatibilities of theory syntax;
  1560 
  1561 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1562 called `inj_on';
  1563 
  1564 * HOL: removed duplicate thms in Arith:
  1565   less_imp_add_less  should be replaced by  trans_less_add1
  1566   le_imp_add_le      should be replaced by  trans_le_add1
  1567 
  1568 * HOL: unary minus is now overloaded (new type constraints may be
  1569 required);
  1570 
  1571 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1572 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1573 now taken as an integer constant.
  1574 
  1575 * Pure: ML function 'theory_of' renamed to 'theory';
  1576 
  1577 
  1578 *** Proof tools ***
  1579 
  1580 * Simplifier:
  1581   1. Asm_full_simp_tac is now more aggressive.
  1582      1. It will sometimes reorient premises if that increases their power to
  1583         simplify.
  1584      2. It does no longer proceed strictly from left to right but may also
  1585         rotate premises to achieve further simplification.
  1586      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1587      old Asm_full_simp_tac in that it does not rotate premises.
  1588   2. The simplifier now knows a little bit about nat-arithmetic.
  1589 
  1590 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1591 allows for selected deletion of wrappers, by introduction of names for
  1592 wrapper functionals.  This implies that addbefore, addSbefore,
  1593 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1594 and that adding two tactics with the same name overwrites the first
  1595 one (emitting a warning).
  1596   type wrapper = (int -> tactic) -> (int -> tactic)
  1597   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1598   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1599   delWrapper, delSWrapper: claset *  string            -> claset
  1600   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1601 
  1602 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1603 semantics; addbefore now affects only the unsafe part of step_tac
  1604 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1605 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1606 by Force_tac;
  1607 
  1608 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1609 compWrapper; added safe wrapper (and access functions for it);
  1610 
  1611 * HOL/split_all_tac is now much faster and fails if there is nothing
  1612 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1613 and the names of the automatically generated variables have changed.
  1614 split_all_tac has moved within claset() from unsafe wrappers to safe
  1615 wrappers, which means that !!-bound variables are split much more
  1616 aggressively, and safe_tac and clarify_tac now split such variables.
  1617 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1618 Note: the same holds for record_split_tac, which does the job of
  1619 split_all_tac for record fields.
  1620 
  1621 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1622 permanently to the default simpset using Addsplits just like
  1623 Addsimps. They can be removed via Delsplits just like
  1624 Delsimps. Lower-case versions are also available.
  1625 
  1626 * HOL/Simplifier: The rule split_if is now part of the default
  1627 simpset. This means that the simplifier will eliminate all occurrences
  1628 of if-then-else in the conclusion of a goal. To prevent this, you can
  1629 either remove split_if completely from the default simpset by
  1630 `Delsplits [split_if]' or remove it in a specific call of the
  1631 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1632 other case splitting rules to/from the default simpset: every datatype
  1633 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1634 t is the name of the datatype).
  1635 
  1636 * Classical reasoner / Simplifier combination: new force_tac (and
  1637 derivatives Force_tac, force) combines rewriting and classical
  1638 reasoning (and whatever other tools) similarly to auto_tac, but is
  1639 aimed to solve the given subgoal completely.
  1640 
  1641 
  1642 *** General ***
  1643 
  1644 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1645 and `goalw': the theory is no longer needed as an explicit argument -
  1646 the current theory context is used; assumptions are no longer returned
  1647 at the ML-level unless one of them starts with ==> or !!; it is
  1648 recommended to convert to these new commands using isatool fixgoal
  1649 (backup your sources first!);
  1650 
  1651 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1652 the current theory context, and 'theory' to lookup stored theories;
  1653 
  1654 * new theory section 'locale' for declaring constants, assumptions and
  1655 definitions that have local scope;
  1656 
  1657 * new theory section 'nonterminals' for purely syntactic types;
  1658 
  1659 * new theory section 'setup' for generic ML setup functions
  1660 (e.g. package initialization);
  1661 
  1662 * the distribution now includes Isabelle icons: see
  1663 lib/logo/isabelle-{small,tiny}.xpm;
  1664 
  1665 * isatool install - install binaries with absolute references to
  1666 ISABELLE_HOME/bin;
  1667 
  1668 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1669 
  1670 * print mode 'emacs' reserved for Isamode;
  1671 
  1672 * support multiple print (ast) translations per constant name;
  1673 
  1674 * theorems involving oracles are now printed with a suffixed [!];
  1675 
  1676 
  1677 *** HOL ***
  1678 
  1679 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1680 
  1681 * HOL/inductive package reorganized and improved: now supports mutual
  1682 definitions such as
  1683 
  1684   inductive EVEN ODD
  1685     intrs
  1686       null "0 : EVEN"
  1687       oddI "n : EVEN ==> Suc n : ODD"
  1688       evenI "n : ODD ==> Suc n : EVEN"
  1689 
  1690 new theorem list "elims" contains an elimination rule for each of the
  1691 recursive sets; inductive definitions now handle disjunctive premises
  1692 correctly (also ZF);
  1693 
  1694 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1695 "mutual_induct" no longer exists - the induction rule is always
  1696 contained in "induct";
  1697 
  1698 
  1699 * HOL/datatype package re-implemented and greatly improved: now
  1700 supports mutually recursive datatypes such as
  1701 
  1702   datatype
  1703     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1704             | SUM ('a aexp) ('a aexp)
  1705             | DIFF ('a aexp) ('a aexp)
  1706             | NUM 'a
  1707   and
  1708     'a bexp = LESS ('a aexp) ('a aexp)
  1709             | AND ('a bexp) ('a bexp)
  1710             | OR ('a bexp) ('a bexp)
  1711 
  1712 as well as indirectly recursive datatypes such as
  1713 
  1714   datatype
  1715     ('a, 'b) term = Var 'a
  1716                   | App 'b ((('a, 'b) term) list)
  1717 
  1718 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1719 induction on mutually / indirectly recursive datatypes.
  1720 
  1721 Primrec equations are now stored in theory and can be accessed via
  1722 <function_name>.simps.
  1723 
  1724 INCOMPATIBILITIES:
  1725 
  1726   - Theories using datatypes must now have theory Datatype as an
  1727     ancestor.
  1728   - The specific <typename>.induct_tac no longer exists - use the
  1729     generic induct_tac instead.
  1730   - natE has been renamed to nat.exhaust - use exhaust_tac
  1731     instead of res_inst_tac ... natE. Note that the variable
  1732     names in nat.exhaust differ from the names in natE, this
  1733     may cause some "fragile" proofs to fail.
  1734   - The theorems split_<typename>_case and split_<typename>_case_asm
  1735     have been renamed to <typename>.split and <typename>.split_asm.
  1736   - Since default sorts of type variables are now handled correctly,
  1737     some datatype definitions may have to be annotated with explicit
  1738     sort constraints.
  1739   - Primrec definitions no longer require function name and type
  1740     of recursive argument.
  1741 
  1742 Consider using isatool fixdatatype to adapt your theories and proof
  1743 scripts to the new package (backup your sources first!).
  1744 
  1745 
  1746 * HOL/record package: considerably improved implementation; now
  1747 includes concrete syntax for record types, terms, updates; theorems
  1748 for surjective pairing and splitting !!-bound record variables; proof
  1749 support is as follows:
  1750 
  1751   1) standard conversions (selectors or updates applied to record
  1752 constructor terms) are part of the standard simpset;
  1753 
  1754   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1755 made part of standard simpset and claset via addIffs;
  1756 
  1757   3) a tactic for record field splitting (record_split_tac) is part of
  1758 the standard claset (addSWrapper);
  1759 
  1760 To get a better idea about these rules you may retrieve them via
  1761 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1762 the name of your record type.
  1763 
  1764 The split tactic 3) conceptually simplifies by the following rule:
  1765 
  1766   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1767 
  1768 Thus any record variable that is bound by meta-all will automatically
  1769 blow up into some record constructor term, consequently the
  1770 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1771 solve record problems automatically.
  1772 
  1773 
  1774 * reorganized the main HOL image: HOL/Integ and String loaded by
  1775 default; theory Main includes everything;
  1776 
  1777 * automatic simplification of integer sums and comparisons, using cancellation;
  1778 
  1779 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1780 
  1781 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1782 
  1783 * many new identities for unions, intersections, set difference, etc.;
  1784 
  1785 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1786 called split_if, split_split, split_sum_case and split_nat_case (to go
  1787 with add/delsplits);
  1788 
  1789 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1790 (?x::unit) = (); this is made part of the default simpset, which COULD
  1791 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1792 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1793 unit_abs_eta_conv is added in order to counter the effect of
  1794 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1795 %u.f();
  1796 
  1797 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1798 makes more sense);
  1799 
  1800 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1801   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1802   disjointness reasoning but breaking a few old proofs.
  1803 
  1804 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1805 to 'converse' from 'inverse' (for compatibility with ZF and some
  1806 literature);
  1807 
  1808 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1809 the well-founded relation;
  1810 
  1811 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1812     Compl A.  The "Compl" syntax remains available as input syntax for this
  1813     release ONLY.
  1814 
  1815 * HOL/Update: new theory of function updates:
  1816     f(a:=b) == %x. if x=a then b else f x
  1817 may also be iterated as in f(a:=b,c:=d,...);
  1818 
  1819 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1820 
  1821 * HOL/List:
  1822   - new function list_update written xs[i:=v] that updates the i-th
  1823     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1824   - new function `upt' written [i..j(] which generates the list
  1825     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1826     bound write [i..j], which is a shorthand for [i..j+1(].
  1827   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1828 
  1829 * HOL/Arith:
  1830   - removed 'pred' (predecessor) function;
  1831   - generalized some theorems about n-1;
  1832   - many new laws about "div" and "mod";
  1833   - new laws about greatest common divisors (see theory ex/Primes);
  1834 
  1835 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1836 instead of "inverse";
  1837 
  1838 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1839   of the multiset ordering;
  1840 
  1841 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1842   (not included by default);
  1843 
  1844 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1845 
  1846 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1847   programs, i.e. different program variables may have different types.
  1848 
  1849 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1850   [previously, this check worked only if the rewrite rule was unconditional]
  1851   Now rew can involve either definitions or equalities (either == or =).
  1852 
  1853 
  1854 *** ZF ***
  1855 
  1856 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1857   only the theorems proved on ZF.ML;
  1858 
  1859 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1860   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1861   disjointness reasoning but breaking a few old proofs.
  1862 
  1863 * ZF/Update: new theory of function updates
  1864     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1865   may also be iterated as in f(a:=b,c:=d,...);
  1866 
  1867 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1868 
  1869 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1870   [previously, this check worked only if the rewrite rule was unconditional]
  1871   Now rew can involve either definitions or equalities (either == or =).
  1872 
  1873 * case_tac provided for compatibility with HOL
  1874     (like the old excluded_middle_tac, but with subgoals swapped)
  1875 
  1876 
  1877 *** Internal programming interfaces ***
  1878 
  1879 * Pure: several new basic modules made available for general use, see
  1880 also src/Pure/README;
  1881 
  1882 * improved the theory data mechanism to support encapsulation (data
  1883 kind name replaced by private Object.kind, acting as authorization
  1884 key); new type-safe user interface via functor TheoryDataFun; generic
  1885 print_data function becomes basically useless;
  1886 
  1887 * removed global_names compatibility flag -- all theory declarations
  1888 are qualified by default;
  1889 
  1890 * module Pure/Syntax now offers quote / antiquote translation
  1891 functions (useful for Hoare logic etc. with implicit dependencies);
  1892 see HOL/ex/Antiquote for an example use;
  1893 
  1894 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1895 cterm -> thm;
  1896 
  1897 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1898 subgoal;
  1899 
  1900 * Display.print_goals function moved to Locale.print_goals;
  1901 
  1902 * standard print function for goals supports current_goals_markers
  1903 variable for marking begin of proof, end of proof, start of goal; the
  1904 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1905 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1906 for example;
  1907 
  1908 
  1909 
  1910 New in Isabelle98 (January 1998)
  1911 --------------------------------
  1912 
  1913 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1914 
  1915 * changed lexical syntax of terms / types: dots made part of long
  1916 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1917 
  1918 * simpset (and claset) reference variable replaced by functions
  1919 simpset / simpset_ref;
  1920 
  1921 * no longer supports theory aliases (via merge) and non-trivial
  1922 implicit merge of thms' signatures;
  1923 
  1924 * most internal names of constants changed due to qualified names;
  1925 
  1926 * changed Pure/Sequence interface (see Pure/seq.ML);
  1927 
  1928 
  1929 *** General Changes ***
  1930 
  1931 * hierachically structured name spaces (for consts, types, axms, thms
  1932 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1933 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1934 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1935 long_names for fully qualified output names; NOTE: ML programs
  1936 (special tactics, packages etc.) referring to internal names may have
  1937 to be adapted to cope with fully qualified names; in case of severe
  1938 backward campatibility problems try setting 'global_names' at compile
  1939 time to have enrything declared within a flat name space; one may also
  1940 fine tune name declarations in theories via the 'global' and 'local'
  1941 section;
  1942 
  1943 * reimplemented the implicit simpset and claset using the new anytype
  1944 data filed in signatures; references simpset:simpset ref etc. are
  1945 replaced by functions simpset:unit->simpset and
  1946 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1947 to patch your ML files accordingly;
  1948 
  1949 * HTML output now includes theory graph data for display with Java
  1950 applet or isatool browser; data generated automatically via isatool
  1951 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1952 
  1953 * defs may now be conditional; improved rewrite_goals_tac to handle
  1954 conditional equations;
  1955 
  1956 * defs now admits additional type arguments, using TYPE('a) syntax;
  1957 
  1958 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1959 creates a new theory node; implicit merge of thms' signatures is
  1960 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1961 transfer:theory->thm->thm in (rare) cases;
  1962 
  1963 * improved handling of draft signatures / theories; draft thms (and
  1964 ctyps, cterms) are automatically promoted to real ones;
  1965 
  1966 * slightly changed interfaces for oracles: admit many per theory, named
  1967 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1968 
  1969 * print_goals: optional output of const types (set show_consts and
  1970 show_types);
  1971 
  1972 * improved output of warnings (###) and errors (***);
  1973 
  1974 * subgoal_tac displays a warning if the new subgoal has type variables;
  1975 
  1976 * removed old README and Makefiles;
  1977 
  1978 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1979 
  1980 * removed obsolete init_pps and init_database;
  1981 
  1982 * deleted the obsolete tactical STATE, which was declared by
  1983     fun STATE tacfun st = tacfun st st;
  1984 
  1985 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1986 (which abbreviates $HOME);
  1987 
  1988 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1989 use isatool fixseq to adapt your ML programs (this works for fully
  1990 qualified references to the Sequence structure only!);
  1991 
  1992 * use_thy no longer requires writable current directory; it always
  1993 reloads .ML *and* .thy file, if either one is out of date;
  1994 
  1995 
  1996 *** Classical Reasoner ***
  1997 
  1998 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1999 tactics that use classical reasoning to simplify a subgoal without
  2000 splitting it into several subgoals;
  2001 
  2002 * Safe_tac: like safe_tac but uses the default claset;
  2003 
  2004 
  2005 *** Simplifier ***
  2006 
  2007 * added simplification meta rules:
  2008     (asm_)(full_)simplify: simpset -> thm -> thm;
  2009 
  2010 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2011 logics (again);
  2012 
  2013 * added prems argument to simplification procedures;
  2014 
  2015 * HOL, FOL, ZF: added infix function `addsplits':
  2016   instead of `<simpset> setloop (split_tac <thms>)'
  2017   you can simply write `<simpset> addsplits <thms>'
  2018 
  2019 
  2020 *** Syntax ***
  2021 
  2022 * TYPE('a) syntax for type reflection terms;
  2023 
  2024 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2025 
  2026 * pretty printer: changed order of mixfix annotation preference (again!);
  2027 
  2028 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2029 
  2030 
  2031 *** HOL ***
  2032 
  2033 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2034   with `addloop' of the simplifier to faciliate case splitting in premises.
  2035 
  2036 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2037 
  2038 * HOL/Auth: new protocol proofs including some for the Internet
  2039   protocol TLS;
  2040 
  2041 * HOL/Map: new theory of `maps' a la VDM;
  2042 
  2043 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2044 cancelling out common nat summands from =, <, <= (in)equalities, or
  2045 differences; simplification procedures nat_cancel_factor for
  2046 cancelling common factor from =, <, <= (in)equalities over natural
  2047 sums; nat_cancel contains both kinds of procedures, it is installed by
  2048 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2049 
  2050 * HOL/simplifier: terms of the form
  2051   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2052   are rewritten to
  2053   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2054   and those of the form
  2055   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2056   are rewritten to
  2057   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2058 
  2059 * HOL/datatype
  2060   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2061 
  2062   P(t_case f1 ... fn x) =
  2063      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2064         ...
  2065        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2066      )
  2067 
  2068   and a theorem `split_t_case_asm' of the form
  2069 
  2070   P(t_case f1 ... fn x) =
  2071     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2072         ...
  2073        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2074      )
  2075   which can be added to a simpset via `addsplits'. The existing theorems
  2076   expand_list_case and expand_option_case have been renamed to
  2077   split_list_case and split_option_case.
  2078 
  2079 * HOL/Arithmetic:
  2080   - `pred n' is automatically converted to `n-1'.
  2081     Users are strongly encouraged not to use `pred' any longer,
  2082     because it will disappear altogether at some point.
  2083   - Users are strongly encouraged to write "0 < n" rather than
  2084     "n ~= 0". Theorems and proof tools have been modified towards this
  2085     `standard'.
  2086 
  2087 * HOL/Lists:
  2088   the function "set_of_list" has been renamed "set" (and its theorems too);
  2089   the function "nth" now takes its arguments in the reverse order and
  2090   has acquired the infix notation "!" as in "xs!n".
  2091 
  2092 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2093 
  2094 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2095   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2096 
  2097 * HOL/record: extensible records with schematic structural subtyping
  2098 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2099 still lacks various theorems and concrete record syntax;
  2100 
  2101 
  2102 *** HOLCF ***
  2103 
  2104 * removed "axioms" and "generated by" sections;
  2105 
  2106 * replaced "ops" section by extended "consts" section, which is capable of
  2107   handling the continuous function space "->" directly;
  2108 
  2109 * domain package:
  2110   . proves theorems immediately and stores them in the theory,
  2111   . creates hierachical name space,
  2112   . now uses normal mixfix annotations (instead of cinfix...),
  2113   . minor changes to some names and values (for consistency),
  2114   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2115   . separator between mutual domain defs: changed "," to "and",
  2116   . improved handling of sort constraints;  now they have to
  2117     appear on the left-hand side of the equations only;
  2118 
  2119 * fixed LAM <x,y,zs>.b syntax;
  2120 
  2121 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2122 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2123 
  2124 
  2125 *** FOL and ZF ***
  2126 
  2127 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2128   with `addloop' of the simplifier to faciliate case splitting in premises.
  2129 
  2130 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2131 in HOL, they strip ALL and --> from proved theorems;
  2132 
  2133 
  2134 
  2135 New in Isabelle94-8 (May 1997)
  2136 ------------------------------
  2137 
  2138 *** General Changes ***
  2139 
  2140 * new utilities to build / run / maintain Isabelle etc. (in parts
  2141 still somewhat experimental); old Makefiles etc. still functional;
  2142 
  2143 * new 'Isabelle System Manual';
  2144 
  2145 * INSTALL text, together with ./configure and ./build scripts;
  2146 
  2147 * reimplemented type inference for greater efficiency, better error
  2148 messages and clean internal interface;
  2149 
  2150 * prlim command for dealing with lots of subgoals (an easier way of
  2151 setting goals_limit);
  2152 
  2153 
  2154 *** Syntax ***
  2155 
  2156 * supports alternative (named) syntax tables (parser and pretty
  2157 printer); internal interface is provided by add_modesyntax(_i);
  2158 
  2159 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2160 be used in conjunction with the Isabelle symbol font; uses the
  2161 "symbols" syntax table;
  2162 
  2163 * added token_translation interface (may translate name tokens in
  2164 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2165 the current print_mode); IMPORTANT: user print translation functions
  2166 are responsible for marking newly introduced bounds
  2167 (Syntax.mark_boundT);
  2168 
  2169 * token translations for modes "xterm" and "xterm_color" that display
  2170 names in bold, underline etc. or colors (which requires a color
  2171 version of xterm);
  2172 
  2173 * infixes may now be declared with names independent of their syntax;
  2174 
  2175 * added typed_print_translation (like print_translation, but may
  2176 access type of constant);
  2177 
  2178 
  2179 *** Classical Reasoner ***
  2180 
  2181 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2182 some limitations.  Blast_tac...
  2183   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2184   + ignores elimination rules that don't have the correct format
  2185         (the conclusion MUST be a formula variable)
  2186   + ignores types, which can make HOL proofs fail
  2187   + rules must not require higher-order unification, e.g. apply_type in ZF
  2188     [message "Function Var's argument not a bound variable" relates to this]
  2189   + its proof strategy is more general but can actually be slower
  2190 
  2191 * substitution with equality assumptions no longer permutes other
  2192 assumptions;
  2193 
  2194 * minor changes in semantics of addafter (now called addaltern); renamed
  2195 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2196 (and access functions for it);
  2197 
  2198 * improved combination of classical reasoner and simplifier:
  2199   + functions for handling clasimpsets
  2200   + improvement of addss: now the simplifier is called _after_ the
  2201     safe steps.
  2202   + safe variant of addss called addSss: uses safe simplifications
  2203     _during_ the safe steps. It is more complete as it allows multiple
  2204     instantiations of unknowns (e.g. with slow_tac).
  2205 
  2206 *** Simplifier ***
  2207 
  2208 * added interface for simplification procedures (functions that
  2209 produce *proven* rewrite rules on the fly, depending on current
  2210 redex);
  2211 
  2212 * ordering on terms as parameter (used for ordered rewriting);
  2213 
  2214 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2215 
  2216 * the solver is now split into a safe and an unsafe part.
  2217 This should be invisible for the normal user, except that the
  2218 functions setsolver and addsolver have been renamed to setSolver and
  2219 addSolver; added safe_asm_full_simp_tac;
  2220 
  2221 
  2222 *** HOL ***
  2223 
  2224 * a generic induction tactic `induct_tac' which works for all datatypes and
  2225 also for type `nat';
  2226 
  2227 * a generic case distinction tactic `exhaust_tac' which works for all
  2228 datatypes and also for type `nat';
  2229 
  2230 * each datatype comes with a function `size';
  2231 
  2232 * patterns in case expressions allow tuple patterns as arguments to
  2233 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2234 
  2235 * primrec now also works with type nat;
  2236 
  2237 * recdef: a new declaration form, allows general recursive functions to be
  2238 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2239 
  2240 * the constant for negation has been renamed from "not" to "Not" to
  2241 harmonize with FOL, ZF, LK, etc.;
  2242 
  2243 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2244 infinite lists;
  2245 
  2246 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2247 
  2248 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2249 problems in commutative rings, using axiomatic type classes for + and *;
  2250 
  2251 * more examples in HOL/MiniML and HOL/Auth;
  2252 
  2253 * more default rewrite rules for quantifiers, union/intersection;
  2254 
  2255 * a new constant `arbitrary == @x.False';
  2256 
  2257 * HOLCF/IOA replaces old HOL/IOA;
  2258 
  2259 * HOLCF changes: derived all rules and arities
  2260   + axiomatic type classes instead of classes
  2261   + typedef instead of faking type definitions
  2262   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2263   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2264   + eliminated the types void, one, tr
  2265   + use unit lift and bool lift (with translations) instead of one and tr
  2266   + eliminated blift from Lift3.thy (use Def instead of blift)
  2267   all eliminated rules are derived as theorems --> no visible changes ;
  2268 
  2269 
  2270 *** ZF ***
  2271 
  2272 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2273 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2274 as ZF_cs addSIs [equalityI];
  2275 
  2276 
  2277 
  2278 New in Isabelle94-7 (November 96)
  2279 ---------------------------------
  2280 
  2281 * allowing negative levels (as offsets) in prlev and choplev;
  2282 
  2283 * super-linear speedup for large simplifications;
  2284 
  2285 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2286 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2287 FAIL); can suppress it using the command Delsimps (ex_simps @
  2288 all_simps); De Morgan laws are also now included, by default;
  2289 
  2290 * improved printing of ==>  :  ~:
  2291 
  2292 * new object-logic "Sequents" adds linear logic, while replacing LK
  2293 and Modal (thanks to Sara Kalvala);
  2294 
  2295 * HOL/Auth: correctness proofs for authentication protocols;
  2296 
  2297 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2298 examples on HOL/Auth);
  2299 
  2300 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2301 the rewriter and classical reasoner simultaneously;
  2302 
  2303 * function uresult no longer returns theorems in "standard" format;
  2304 regain previous version by: val uresult = standard o uresult;
  2305 
  2306 
  2307 
  2308 New in Isabelle94-6
  2309 -------------------
  2310 
  2311 * oracles -- these establish an interface between Isabelle and trusted
  2312 external reasoners, which may deliver results as theorems;
  2313 
  2314 * proof objects (in particular record all uses of oracles);
  2315 
  2316 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2317 
  2318 * "constdefs" section in theory files;
  2319 
  2320 * "primrec" section (HOL) no longer requires names;
  2321 
  2322 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2323 
  2324 
  2325 
  2326 New in Isabelle94-5
  2327 -------------------
  2328 
  2329 * reduced space requirements;
  2330 
  2331 * automatic HTML generation from theories;
  2332 
  2333 * theory files no longer require "..." (quotes) around most types;
  2334 
  2335 * new examples, including two proofs of the Church-Rosser theorem;
  2336 
  2337 * non-curried (1994) version of HOL is no longer distributed;
  2338 
  2339 
  2340 
  2341 New in Isabelle94-4
  2342 -------------------
  2343 
  2344 * greatly reduced space requirements;
  2345 
  2346 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2347 
  2348 * searchable theorem database (see the section "Retrieving theorems" on
  2349 page 8 of the Reference Manual);
  2350 
  2351 * new examples, including Grabczewski's monumental case study of the
  2352 Axiom of Choice;
  2353 
  2354 * The previous version of HOL renamed to Old_HOL;
  2355 
  2356 * The new version of HOL (previously called CHOL) uses a curried syntax
  2357 for functions.  Application looks like f a b instead of f(a,b);
  2358 
  2359 * Mutually recursive inductive definitions finally work in HOL;
  2360 
  2361 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2362 translates to the operator "split";
  2363 
  2364 
  2365 
  2366 New in Isabelle94-3
  2367 -------------------
  2368 
  2369 * new infix operator, addss, allowing the classical reasoner to
  2370 perform simplification at each step of its search.  Example:
  2371         fast_tac (cs addss ss)
  2372 
  2373 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2374 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2375 look like (a,b) instead of <a,b>;
  2376 
  2377 * PLEASE NOTE: CHOL will eventually replace HOL!
  2378 
  2379 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2380 It translates to the operator "split".  A new theory of integers is available;
  2381 
  2382 * In ZF, integer numerals now denote two's-complement binary integers.
  2383 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2384 
  2385 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2386 of the Axiom of Choice;
  2387 
  2388 
  2389 
  2390 New in Isabelle94-2
  2391 -------------------
  2392 
  2393 * Significantly faster resolution;
  2394 
  2395 * the different sections in a .thy file can now be mixed and repeated
  2396 freely;
  2397 
  2398 * Database of theorems for FOL, HOL and ZF.  New
  2399 commands including qed, qed_goal and bind_thm store theorems in the database.
  2400 
  2401 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2402 a given theory (thms_of), or find out what theory a theorem was proved in
  2403 (theory_of_thm);
  2404 
  2405 * Bugs fixed in the inductive definition and datatype packages;
  2406 
  2407 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2408 and HOL_dup_cs obsolete;
  2409 
  2410 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2411 have been removed;
  2412 
  2413 * Simpler definition of function space in ZF;
  2414 
  2415 * new results about cardinal and ordinal arithmetic in ZF;
  2416 
  2417 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2418 types;
  2419 
  2420 
  2421 $Id$