NEWS
author ballarin
Thu Nov 28 10:50:42 2002 +0100 (2002-11-28)
changeset 13735 7de9342aca7a
parent 13648 610cedff5538
child 13745 a31e04831dd1
permissions -rw-r--r--
HOL-Algebra partially ported to Isar.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/linorder: New generic prover for transitivity reasoning over
    10 linear orders.  Note: this prover is not efficient!
    11 
    12 * Provers/simplifier:
    13 
    14   - Completely reimplemented Asm_full_simp_tac:
    15     Assumptions are now subject to complete mutual simplification,
    16     not just from left to right. The simplifier now preserves
    17     the order of assumptions.
    18 
    19     Potential INCOMPATIBILITY:
    20 
    21     -- Asm_full_simp_tac sometimes diverges where the old version did
    22        not, e.g. invoking Asm_full_simp_tac on the goal
    23 
    24         [| P (f x); y = x; f x = f y |] ==> Q
    25 
    26       now gives rise to the infinite reduction sequence
    27 
    28         P (f x) --(f x = f y)--> P (f y) --(y = x)--> P (f x) --(f x = f y)--> ...
    29 
    30       Using Asm_lr_simp_tac (or "simp (asm_lr)" in Isabelle/Isar) instead
    31       often solves this kind of problem.
    32 
    33     -- Tactics combining classical reasoner and simplification (such
    34        as auto) are also affected by this change, because many of them
    35        rely on Asm_full_simp_tac. They may sometimes diverge as well
    36        or yield a different numbers of subgoals. Try to use e.g. force,
    37        fastsimp, or safe instead of auto in case of problems. Sometimes
    38        subsequent calls to the classical reasoner will fail because a
    39        preceeding call to the simplifier too eagerly simplified the
    40        goal, e.g. deleted redundant premises.
    41 
    42   - The simplifier trace now shows the names of the applied rewrite rules
    43 
    44 * Pure: new flag trace_unify_fail causes unification to print
    45 diagnostic information (PG: in trace buffer) when it fails. This is
    46 useful for figuring out why single step proofs like rule, erule or
    47 assumption failed.
    48 
    49 * Pure: you can find all matching introduction rules for subgoal 1,
    50   i.e. all rules whose conclusion matches subgoal 1, by executing
    51   ML"ProofGeneral.print_intros()"
    52   The rules are ordered by how closely they match the subgoal.
    53   In particular, rules that solve a subgoal outright are displayed first
    54   (or rather last, the way it is printed).
    55   TODO: integration with PG
    56 
    57 * Pure: locale specifications now produce predicate definitions
    58 according to the body of text (covering assumptions modulo local
    59 definitions); predicate "loc_axioms" covers newly introduced text,
    60 while "loc" is cumulative wrt. all included locale expressions; the
    61 latter view is presented only on export into the global theory
    62 context; potential INCOMPATIBILITY, use "(open)" option to fall back
    63 on the old view without predicates;
    64 
    65 * Pure: predefined locales "var" and "struct" are useful for sharing
    66 parameters (as in CASL, for example); just specify something like
    67 ``var x + var y + struct M'' as import;
    68 
    69 * Pure: improved thms_containing: proper indexing of facts instead of
    70 raw theorems; check validity of results wrt. current name space;
    71 include local facts of proof configuration (also covers active
    72 locales), cover fixed variables in index; may use "_" in term
    73 specification; an optional limit for the number of printed facts may
    74 be given (the default is 40);
    75 
    76 * Pure: disallow duplicate fact bindings within new-style theory files
    77 (batch-mode only);
    78 
    79 * Provers: improved induct method: assumptions introduced by case
    80 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
    81 the goal statement); "foo" still refers to all facts collectively;
    82 
    83 * Provers: the function blast.overloaded has been removed: all constants
    84 are regarded as potentially overloaded, which improves robustness in exchange
    85 for slight decrease in efficiency;
    86 
    87 * Isar: preview of problems to finish 'show' now produce an error
    88 rather than just a warning (in interactive mode);
    89 
    90 
    91 *** HOL ***
    92 
    93 * New tactic "trans_tac" and method "trans" instantiate
    94 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
    95 "<=", "<" and "="). 
    96 
    97 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
    98 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
    99 
   100 * 'typedef' command has new option "open" to suppress the set
   101 definition;
   102 
   103 * functions Min and Max on finite sets have been introduced (theory
   104 Finite_Set);
   105 
   106 * attribute [symmetric] now works for relations as well; it turns
   107 (x,y) : R^-1 into (y,x) : R, and vice versa;
   108 
   109 * arith(_tac) now produces a counter example if it cannot prove a theorem.
   110   In ProofGeneral the counter example appears in the trace buffer.
   111 
   112 * arith(_tac) does now know about div k and mod k where k is a numeral
   113 of type nat or int. It can solve simple goals like
   114 
   115   "0 < n ==> n div 2 < (n::nat)"
   116 
   117 but fails if divisibility plays a role like in
   118 
   119   "n div 2 + (n+1) div 2 = (n::nat)"
   120 
   121 * simp's arithmetic capabilities have been enhanced a bit: it now
   122 takes ~= in premises into account (by performing a case split);
   123 
   124 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   125 are distributed over a sum of terms;
   126 
   127 * induct over a !!-quantified statement (say !!x1..xn):
   128   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   129 
   130 * GroupTheory: converted to Isar theories, using locales with implicit structures;
   131 
   132 * Real/HahnBanach: updated and adapted to locales;
   133 
   134 
   135 *** ZF ***
   136 
   137 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   138 universe, etc.);
   139 
   140 * Main ZF: many theories converted to new-style format;
   141 
   142 
   143 *** ML ***
   144 
   145 * Pure: Tactic.prove provides sane interface for internal proofs;
   146 omits the infamous "standard" operation, so this is more appropriate
   147 than prove_goalw_cterm in many situations (e.g. in simprocs);
   148 
   149 * Pure: improved error reporting of simprocs;
   150 
   151 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   152 up simprocs;
   153 
   154 
   155 
   156 New in Isabelle2002 (March 2002)
   157 --------------------------------
   158 
   159 *** Document preparation ***
   160 
   161 * greatly simplified document preparation setup, including more
   162 graceful interpretation of isatool usedir -i/-d/-D options, and more
   163 instructive isatool mkdir; users should basically be able to get
   164 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   165 users may run a separate document processing stage manually like this:
   166 "isatool usedir -D output HOL Test && isatool document Test/output";
   167 
   168 * theory dependency graph may now be incorporated into documents;
   169 isatool usedir -g true will produce session_graph.eps/.pdf for use
   170 with \includegraphics of LaTeX;
   171 
   172 * proper spacing of consecutive markup elements, especially text
   173 blocks after section headings;
   174 
   175 * support bold style (for single symbols only), input syntax is like
   176 this: "\<^bold>\<alpha>" or "\<^bold>A";
   177 
   178 * \<bullet> is now output as bold \cdot by default, which looks much
   179 better in printed text;
   180 
   181 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   182 note that these symbols are currently unavailable in Proof General /
   183 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   184 
   185 * isatool latex no longer depends on changed TEXINPUTS, instead
   186 isatool document copies the Isabelle style files to the target
   187 location;
   188 
   189 
   190 *** Isar ***
   191 
   192 * Pure/Provers: improved proof by cases and induction;
   193   - 'case' command admits impromptu naming of parameters (such as
   194     "case (Suc n)");
   195   - 'induct' method divinates rule instantiation from the inductive
   196     claim; no longer requires excessive ?P bindings for proper
   197     instantiation of cases;
   198   - 'induct' method properly enumerates all possibilities of set/type
   199     rules; as a consequence facts may be also passed through *type*
   200     rules without further ado;
   201   - 'induct' method now derives symbolic cases from the *rulified*
   202     rule (before it used to rulify cases stemming from the internal
   203     atomized version); this means that the context of a non-atomic
   204     statement becomes is included in the hypothesis, avoiding the
   205     slightly cumbersome show "PROP ?case" form;
   206   - 'induct' may now use elim-style induction rules without chaining
   207     facts, using ``missing'' premises from the goal state; this allows
   208     rules stemming from inductive sets to be applied in unstructured
   209     scripts, while still benefitting from proper handling of non-atomic
   210     statements; NB: major inductive premises need to be put first, all
   211     the rest of the goal is passed through the induction;
   212   - 'induct' proper support for mutual induction involving non-atomic
   213     rule statements (uses the new concept of simultaneous goals, see
   214     below);
   215   - append all possible rule selections, but only use the first
   216     success (no backtracking);
   217   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   218   - undeclared rule case names default to numbers 1, 2, 3, ...;
   219   - added 'print_induct_rules' (covered by help item in recent Proof
   220     General versions);
   221   - moved induct/cases attributes to Pure, methods to Provers;
   222   - generic method setup instantiated for FOL and HOL;
   223 
   224 * Pure: support multiple simultaneous goal statements, for example
   225 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   226 meta-level mechanism, this acts as if several individual goals had
   227 been stated separately; in particular common proof methods need to be
   228 repeated in order to cover all claims; note that a single elimination
   229 step is *not* sufficient to establish the two conjunctions, so this
   230 fails:
   231 
   232   assume "A & B" then have A and B ..   (*".." fails*)
   233 
   234 better use "obtain" in situations as above; alternative refer to
   235 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   236 
   237 * Pure: proper integration with ``locales''; unlike the original
   238 version by Florian Kammüller, Isar locales package high-level proof
   239 contexts rather than raw logical ones (e.g. we admit to include
   240 attributes everywhere); operations on locales include merge and
   241 rename; support for implicit arguments (``structures''); simultaneous
   242 type-inference over imports and text; see also HOL/ex/Locales.thy for
   243 some examples;
   244 
   245 * Pure: the following commands have been ``localized'', supporting a
   246 target locale specification "(in name)": 'lemma', 'theorem',
   247 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   248 stored both within the locale and at the theory level (exported and
   249 qualified by the locale name);
   250 
   251 * Pure: theory goals may now be specified in ``long'' form, with
   252 ad-hoc contexts consisting of arbitrary locale elements. for example
   253 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   254 definitions may be given, too); the result is a meta-level rule with
   255 the context elements being discharged in the obvious way;
   256 
   257 * Pure: new proof command 'using' allows to augment currently used
   258 facts after a goal statement ('using' is syntactically analogous to
   259 'apply', but acts on the goal's facts only); this allows chained facts
   260 to be separated into parts given before and after a claim, as in
   261 ``from a and b have C using d and e <proof>'';
   262 
   263 * Pure: renamed "antecedent" case to "rule_context";
   264 
   265 * Pure: new 'judgment' command records explicit information about the
   266 object-logic embedding (used by several tools internally); no longer
   267 use hard-wired "Trueprop";
   268 
   269 * Pure: added 'corollary' command;
   270 
   271 * Pure: fixed 'token_translation' command;
   272 
   273 * Pure: removed obsolete 'exported' attribute;
   274 
   275 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   276 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   277 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   278 
   279 * Pure: method 'atomize' presents local goal premises as object-level
   280 statements (atomic meta-level propositions); setup controlled via
   281 rewrite rules declarations of 'atomize' attribute; example
   282 application: 'induct' method with proper rule statements in improper
   283 proof *scripts*;
   284 
   285 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   286 now consider the syntactic context of assumptions, giving a better
   287 chance to get type-inference of the arguments right (this is
   288 especially important for locales);
   289 
   290 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   291 mode;
   292 
   293 * Pure/obtain: the formal conclusion "thesis", being marked as
   294 ``internal'', may no longer be reference directly in the text;
   295 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   296 situations;
   297 
   298 * Pure: generic 'sym' attribute which declares a rule both as pure
   299 'elim?' and for the 'symmetric' operation;
   300 
   301 * Pure: marginal comments ``--'' may now occur just anywhere in the
   302 text; the fixed correlation with particular command syntax has been
   303 discontinued;
   304 
   305 * Pure: new method 'rules' is particularly well-suited for proof
   306 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   307 but often produces more compact proof terms with less detours;
   308 
   309 * Pure/Provers/classical: simplified integration with pure rule
   310 attributes and methods; the classical "intro?/elim?/dest?"
   311 declarations coincide with the pure ones; the "rule" method no longer
   312 includes classically swapped intros; "intro" and "elim" methods no
   313 longer pick rules from the context; also got rid of ML declarations
   314 AddXIs/AddXEs/AddXDs; all of this has some potential for
   315 INCOMPATIBILITY;
   316 
   317 * Provers/classical: attribute 'swapped' produces classical inversions
   318 of introduction rules;
   319 
   320 * Provers/simplifier: 'simplified' attribute may refer to explicit
   321 rules instead of full simplifier context; 'iff' attribute handles
   322 conditional rules;
   323 
   324 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   325 
   326 * HOL: 'recdef' now fails on unfinished automated proofs, use
   327 "(permissive)" option to recover old behavior;
   328 
   329 * HOL: 'inductive' no longer features separate (collective) attributes
   330 for 'intros' (was found too confusing);
   331 
   332 * HOL: properly declared induction rules less_induct and
   333 wf_induct_rule;
   334 
   335 
   336 *** HOL ***
   337 
   338 * HOL: moved over to sane numeral syntax; the new policy is as
   339 follows:
   340 
   341   - 0 and 1 are polymorphic constants, which are defined on any
   342   numeric type (nat, int, real etc.);
   343 
   344   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   345   binary representation internally;
   346 
   347   - type nat has special constructor Suc, and generally prefers Suc 0
   348   over 1::nat and Suc (Suc 0) over 2::nat;
   349 
   350 This change may cause significant problems of INCOMPATIBILITY; here
   351 are some hints on converting existing sources:
   352 
   353   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   354   entities, so expressions involving "-" (unary or binary minus) need
   355   to be spaced properly;
   356 
   357   - existing occurrences of "1" may need to be constraint "1::nat" or
   358   even replaced by Suc 0; similar for old "2";
   359 
   360   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   361 
   362   - remove all special provisions on numerals in proofs;
   363 
   364 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   365 representation (depends on bin_arith_simps in the default context);
   366 
   367 * HOL: symbolic syntax for x^2 (numeral 2);
   368 
   369 * HOL: the class of all HOL types is now called "type" rather than
   370 "term"; INCOMPATIBILITY, need to adapt references to this type class
   371 in axclass/classes, instance/arities, and (usually rare) occurrences
   372 in typings (of consts etc.); internally the class is called
   373 "HOL.type", ML programs should refer to HOLogic.typeS;
   374 
   375 * HOL/record package improvements:
   376   - new derived operations "fields" to build a partial record section,
   377     "extend" to promote a fixed record to a record scheme, and
   378     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   379     declared as simp by default;
   380   - shared operations ("more", "fields", etc.) now need to be always
   381     qualified) --- potential INCOMPATIBILITY;
   382   - removed "make_scheme" operations (use "make" with "extend") --
   383     INCOMPATIBILITY;
   384   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   385   - provides cases/induct rules for use with corresponding Isar
   386     methods (for concrete records, record schemes, concrete more
   387     parts, and schematic more parts -- in that order);
   388   - internal definitions directly based on a light-weight abstract
   389     theory of product types over typedef rather than datatype;
   390 
   391 * HOL: generic code generator for generating executable ML code from
   392 specifications; specific support for HOL constructs such as inductive
   393 datatypes and sets, as well as recursive functions; can be invoked
   394 via 'generate_code' theory section;
   395 
   396 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   397 
   398 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   399 (beware of argument permutation!);
   400 
   401 * HOL: linorder_less_split superseded by linorder_cases;
   402 
   403 * HOL/List: "nodups" renamed to "distinct";
   404 
   405 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   406 to peripheral theory "Hilbert_Choice";
   407 
   408 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   409 in this (rare) case use:
   410 
   411   delSWrapper "split_all_tac"
   412   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   413 
   414 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   415 MAY FAIL;
   416 
   417 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   418 Isabelle's type classes, ^ on functions and relations has too general
   419 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   420 necessary to attach explicit type constraints;
   421 
   422 * HOL/Relation: the prefix name of the infix "O" has been changed from
   423 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   424 renamed accordingly (eg "compI" -> "rel_compI").
   425 
   426 * HOL: syntax translations now work properly with numerals and records
   427 expressions;
   428 
   429 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   430 of "lam" -- INCOMPATIBILITY;
   431 
   432 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   433 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   434 renamed "Product_Type.unit";
   435 
   436 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   437 
   438 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   439 the "cases" method);
   440 
   441 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   442 Florian Kammüller);
   443 
   444 * HOL/IMP: updated and converted to new-style theory format; several
   445 parts turned into readable document, with proper Isar proof texts and
   446 some explanations (by Gerwin Klein);
   447 
   448 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   449 
   450 * HOL-Hyperreal is now a logic image;
   451 
   452 
   453 *** HOLCF ***
   454 
   455 * Isar: consts/constdefs supports mixfix syntax for continuous
   456 operations;
   457 
   458 * Isar: domain package adapted to new-style theory format, e.g. see
   459 HOLCF/ex/Dnat.thy;
   460 
   461 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   462 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   463 lift.induct_tac, always use UU instead of Undef;
   464 
   465 * HOLCF/IMP: updated and converted to new-style theory;
   466 
   467 
   468 *** ZF ***
   469 
   470 * Isar: proper integration of logic-specific tools and packages,
   471 including theory commands '(co)inductive', '(co)datatype',
   472 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   473 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   474 
   475 * theory Main no longer includes AC; for the Axiom of Choice, base
   476 your theory on Main_ZFC;
   477 
   478 * the integer library now covers quotients and remainders, with many
   479 laws relating division to addition, multiplication, etc.;
   480 
   481 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   482 typeless version of the formalism;
   483 
   484 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   485 format;
   486 
   487 * ZF/Induct: new directory for examples of inductive definitions,
   488 including theory Multiset for multiset orderings; converted to
   489 new-style theory format;
   490 
   491 * ZF: many new theorems about lists, ordinals, etc.;
   492 
   493 
   494 *** General ***
   495 
   496 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   497 variable proof controls level of detail: 0 = no proofs (only oracle
   498 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   499 also ref manual for further ML interfaces;
   500 
   501 * Pure/axclass: removed obsolete ML interface
   502 goal_subclass/goal_arity;
   503 
   504 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   505 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   506 separate tokens, so expressions involving minus need to be spaced
   507 properly;
   508 
   509 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   510 rather than "infixl" or "infixr";
   511 
   512 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   513 sort constraint specifications in type inference; e.g. "x::_::foo"
   514 ensures that the type of "x" is of sort "foo" (but not necessarily a
   515 type variable);
   516 
   517 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   518 control output of nested => (types); the default behavior is
   519 "type_brackets";
   520 
   521 * Pure/syntax: builtin parse translation for "_constify" turns valued
   522 tokens into AST constants;
   523 
   524 * Pure/syntax: prefer later declarations of translations and print
   525 translation functions; potential INCOMPATIBILITY: need to reverse
   526 multiple declarations for same syntax element constant;
   527 
   528 * Pure/show_hyps reset by default (in accordance to existing Isar
   529 practice);
   530 
   531 * Provers/classical: renamed addaltern to addafter, addSaltern to
   532 addSafter;
   533 
   534 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   535 as well;
   536 
   537 * system: tested support for MacOS X; should be able to get Isabelle +
   538 Proof General to work in a plain Terminal after installing Poly/ML
   539 (e.g. from the Isabelle distribution area) and GNU bash alone
   540 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   541 support requires further installations, e.g. from
   542 http://fink.sourceforge.net/);
   543 
   544 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   545 
   546 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   547 of 40 MB), cf. ML_OPTIONS;
   548 
   549 * system: Proof General keywords specification is now part of the
   550 Isabelle distribution (see etc/isar-keywords.el);
   551 
   552 * system: support for persistent Proof General sessions (refrain from
   553 outdating all loaded theories on startup); user may create writable
   554 logic images like this: ``isabelle -q HOL Test'';
   555 
   556 * system: smart selection of Isabelle process versus Isabelle
   557 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   558 run both "isabelle" and "Isabelle" even if file names are badly
   559 damaged (executable inspects the case of the first letter of its own
   560 name); added separate "isabelle-process" and "isabelle-interface";
   561 
   562 * system: refrain from any attempt at filtering input streams; no
   563 longer support ``8bit'' encoding of old isabelle font, instead proper
   564 iso-latin characters may now be used; the related isatools
   565 "symbolinput" and "nonascii" have disappeared as well;
   566 
   567 * system: removed old "xterm" interface (the print modes "xterm" and
   568 "xterm_color" are still available for direct use in a suitable
   569 terminal);
   570 
   571 
   572 
   573 New in Isabelle99-2 (February 2001)
   574 -----------------------------------
   575 
   576 *** Overview of INCOMPATIBILITIES ***
   577 
   578 * HOL: please note that theories in the Library and elsewhere often use the
   579 new-style (Isar) format; to refer to their theorems in an ML script you must
   580 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   581 
   582 * HOL: inductive package no longer splits induction rule aggressively,
   583 but only as far as specified by the introductions given; the old
   584 format may be recovered via ML function complete_split_rule or attribute
   585 'split_rule (complete)';
   586 
   587 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   588 gfp_Tarski to gfp_unfold;
   589 
   590 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   591 
   592 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   593 relation); infix "^^" has been renamed "``"; infix "``" has been
   594 renamed "`"; "univalent" has been renamed "single_valued";
   595 
   596 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   597 operation;
   598 
   599 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   600 
   601 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   602 
   603 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   604 consequence, it is no longer monotonic wrt. the local goal context
   605 (which is now passed through the inductive cases);
   606 
   607 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   608 \<gg> to \<ggreater>;
   609 
   610 
   611 *** Document preparation ***
   612 
   613 * \isabellestyle{NAME} selects version of Isabelle output (currently
   614 available: are "it" for near math-mode best-style output, "sl" for
   615 slanted text style, and "tt" for plain type-writer; if no
   616 \isabellestyle command is given, output is according to slanted
   617 type-writer);
   618 
   619 * support sub/super scripts (for single symbols only), input syntax is
   620 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   621 
   622 * some more standard symbols; see Appendix A of the system manual for
   623 the complete list of symbols defined in isabellesym.sty;
   624 
   625 * improved isabelle style files; more abstract symbol implementation
   626 (should now use \isamath{...} and \isatext{...} in custom symbol
   627 definitions);
   628 
   629 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   630 state; Note that presentation of goal states does not conform to
   631 actual human-readable proof documents.  Please do not include goal
   632 states into document output unless you really know what you are doing!
   633 
   634 * proper indentation of antiquoted output with proportional LaTeX
   635 fonts;
   636 
   637 * no_document ML operator temporarily disables LaTeX document
   638 generation;
   639 
   640 * isatool unsymbolize tunes sources for plain ASCII communication;
   641 
   642 
   643 *** Isar ***
   644 
   645 * Pure: Isar now suffers initial goal statements to contain unbound
   646 schematic variables (this does not conform to actual readable proof
   647 documents, due to unpredictable outcome and non-compositional proof
   648 checking); users who know what they are doing may use schematic goals
   649 for Prolog-style synthesis of proven results;
   650 
   651 * Pure: assumption method (an implicit finishing) now handles actual
   652 rules as well;
   653 
   654 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   655 initial goal, declare "that" only as Pure intro (only for single
   656 steps); the "that" rule assumption may now be involved in implicit
   657 finishing, thus ".." becomes a feasible for trivial obtains;
   658 
   659 * Pure: default proof step now includes 'intro_classes'; thus trivial
   660 instance proofs may be performed by "..";
   661 
   662 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   663 statements as well;
   664 
   665 * Pure: more robust selection of calculational rules;
   666 
   667 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   668 rule (as well as the assumption rule);
   669 
   670 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   671 lemmas, using the graph browser tool;
   672 
   673 * Pure: predict failure of "show" in interactive mode;
   674 
   675 * Pure: 'thms_containing' now takes actual terms as arguments;
   676 
   677 * HOL: improved method 'induct' --- now handles non-atomic goals
   678 (potential INCOMPATIBILITY); tuned error handling;
   679 
   680 * HOL: cases and induct rules now provide explicit hints about the
   681 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   682 any remaining facts are inserted into the goal verbatim;
   683 
   684 * HOL: local contexts (aka cases) may now contain term bindings as
   685 well; the 'cases' and 'induct' methods new provide a ?case binding for
   686 the result to be shown in each case;
   687 
   688 * HOL: added 'recdef_tc' command;
   689 
   690 * isatool convert assists in eliminating legacy ML scripts;
   691 
   692 
   693 *** HOL ***
   694 
   695 * HOL/Library: a collection of generic theories to be used together
   696 with main HOL; the theory loader path already includes this directory
   697 by default; the following existing theories have been moved here:
   698 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   699 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   700 
   701 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   702 modelling and verification task performed in Isabelle/HOL +
   703 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   704 
   705 * HOL/Algebra: special summation operator SUM no longer exists, it has
   706 been replaced by setsum; infix 'assoc' now has priority 50 (like
   707 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   708 'domain', this makes the theory consistent with mathematical
   709 literature;
   710 
   711 * HOL basics: added overloaded operations "inverse" and "divide"
   712 (infix "/"), syntax for generic "abs" operation, generic summation
   713 operator \<Sum>;
   714 
   715 * HOL/typedef: simplified package, provide more useful rules (see also
   716 HOL/subset.thy);
   717 
   718 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   719 now expressed as a proper nested rule (old-style tactic scripts may
   720 require atomize_strip_tac to cope with non-atomic premises);
   721 
   722 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   723 to "split_conv" (old name still available for compatibility);
   724 
   725 * HOL: improved concrete syntax for strings (e.g. allows translation
   726 rules with string literals);
   727 
   728 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   729  and Fleuriot's mechanization of analysis, including the transcendental
   730  functions for the reals;
   731 
   732 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   733 
   734 
   735 *** CTT ***
   736 
   737 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   738 "lam" is displayed as TWO lambda-symbols
   739 
   740 * CTT: theory Main now available, containing everything (that is, Bool
   741 and Arith);
   742 
   743 
   744 *** General ***
   745 
   746 * Pure: the Simplifier has been implemented properly as a derived rule
   747 outside of the actual kernel (at last!); the overall performance
   748 penalty in practical applications is about 50%, while reliability of
   749 the Isabelle inference kernel has been greatly improved;
   750 
   751 * print modes "brackets" and "no_brackets" control output of nested =>
   752 (types) and ==> (props); the default behaviour is "brackets";
   753 
   754 * Provers: fast_tac (and friends) now handle actual object-logic rules
   755 as assumptions as well;
   756 
   757 * system: support Poly/ML 4.0;
   758 
   759 * system: isatool install handles KDE version 1 or 2;
   760 
   761 
   762 
   763 New in Isabelle99-1 (October 2000)
   764 ----------------------------------
   765 
   766 *** Overview of INCOMPATIBILITIES ***
   767 
   768 * HOL: simplification of natural numbers is much changed; to partly
   769 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   770 issue the following ML commands:
   771 
   772   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   773   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   774 
   775 * HOL: simplification no longer dives into case-expressions; this is
   776 controlled by "t.weak_case_cong" for each datatype t;
   777 
   778 * HOL: nat_less_induct renamed to less_induct;
   779 
   780 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   781 fixsome to patch .thy and .ML sources automatically;
   782 
   783   select_equality  -> some_equality
   784   select_eq_Ex     -> some_eq_ex
   785   selectI2EX       -> someI2_ex
   786   selectI2         -> someI2
   787   selectI          -> someI
   788   select1_equality -> some1_equality
   789   Eps_sym_eq       -> some_sym_eq_trivial
   790   Eps_eq           -> some_eq_trivial
   791 
   792 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   793 
   794 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   795 instead);
   796 
   797 * HOL: the recursion equations generated by 'recdef' are now called
   798 f.simps instead of f.rules;
   799 
   800 * HOL: qed_spec_mp now also handles bounded ALL as well;
   801 
   802 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   803 sometimes be needed;
   804 
   805 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   806 
   807 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   808 
   809 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   810 product is now "<*>" instead of "Times"; the lexicographic product is
   811 now "<*lex*>" instead of "**";
   812 
   813 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   814 of main HOL, but was unused); better use HOL's datatype package;
   815 
   816 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   817 the old syntax may be recovered as follows:
   818 
   819   syntax (symbols)
   820     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   821       (infixl "\\<oplus>" 100)
   822 
   823 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   824 
   825 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   826 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   827 internally;
   828 
   829 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   830 changed from A/r to A//r;
   831 
   832 * ZF: new treatment of arithmetic (nat & int) may break some old
   833 proofs;
   834 
   835 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   836 rulify -> rule_format, elimify -> elim_format, ...);
   837 
   838 * Isar/Provers: intro/elim/dest attributes changed; renamed
   839 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   840 should have to change intro!! to intro? only); replaced "delrule" by
   841 "rule del";
   842 
   843 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   844 
   845 * Provers: strengthened force_tac by using new first_best_tac;
   846 
   847 * LaTeX document preparation: several changes of isabelle.sty (see
   848 lib/texinputs);
   849 
   850 
   851 *** Document preparation ***
   852 
   853 * formal comments (text blocks etc.) in new-style theories may now
   854 contain antiquotations of thm/prop/term/typ/text to be presented
   855 according to latex print mode; concrete syntax is like this:
   856 @{term[show_types] "f(x) = a + x"};
   857 
   858 * isatool mkdir provides easy setup of Isabelle session directories,
   859 including proper document sources;
   860 
   861 * generated LaTeX sources are now deleted after successful run
   862 (isatool document -c); may retain a copy somewhere else via -D option
   863 of isatool usedir;
   864 
   865 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   866 style files, achieving self-contained LaTeX sources and simplifying
   867 LaTeX debugging;
   868 
   869 * old-style theories now produce (crude) LaTeX output as well;
   870 
   871 * browser info session directories are now self-contained (may be put
   872 on WWW server seperately); improved graphs of nested sessions; removed
   873 graph for 'all sessions';
   874 
   875 * several improvements in isabelle style files; \isabellestyle{it}
   876 produces fake math mode output; \isamarkupheader is now \section by
   877 default; see lib/texinputs/isabelle.sty etc.;
   878 
   879 
   880 *** Isar ***
   881 
   882 * Isar/Pure: local results and corresponding term bindings are now
   883 subject to Hindley-Milner polymorphism (similar to ML); this
   884 accommodates incremental type-inference very nicely;
   885 
   886 * Isar/Pure: new derived language element 'obtain' supports
   887 generalized existence reasoning;
   888 
   889 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   890 support accumulation of results, without applying any rules yet;
   891 useful to collect intermediate results without explicit name
   892 references, and for use with transitivity rules with more than 2
   893 premises;
   894 
   895 * Isar/Pure: scalable support for case-analysis type proofs: new
   896 'case' language element refers to local contexts symbolically, as
   897 produced by certain proof methods; internally, case names are attached
   898 to theorems as "tags";
   899 
   900 * Isar/Pure: theory command 'hide' removes declarations from
   901 class/type/const name spaces;
   902 
   903 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   904 indicate potential overloading;
   905 
   906 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   907 
   908 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   909 "{a,b,c}" instead of {a,b,c};
   910 
   911 * Isar/Pure now provides its own version of intro/elim/dest
   912 attributes; useful for building new logics, but beware of confusion
   913 with the version in Provers/classical;
   914 
   915 * Isar/Pure: the local context of (non-atomic) goals is provided via
   916 case name 'antecedent';
   917 
   918 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   919 to the current context is now done automatically);
   920 
   921 * Isar/Pure: theory command 'method_setup' provides a simple interface
   922 for definining proof methods in ML;
   923 
   924 * Isar/Provers: intro/elim/dest attributes changed; renamed
   925 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   926 most cases, one should have to change intro!! to intro? only);
   927 replaced "delrule" by "rule del";
   928 
   929 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   930 'symmetric' attribute (the latter supercedes [RS sym]);
   931 
   932 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   933 method modifier); 'simp' method: 'only:' modifier removes loopers as
   934 well (including splits);
   935 
   936 * Isar/Provers: Simplifier and Classical methods now support all kind
   937 of modifiers used in the past, including 'cong', 'iff', etc.
   938 
   939 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   940 of Simplifier and Classical reasoner);
   941 
   942 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   943 now support named cases; major packages (inductive, datatype, primrec,
   944 recdef) support case names and properly name parameters;
   945 
   946 * Isar/HOL: new transitivity rules for substitution in inequalities --
   947 monotonicity conditions are extracted to be proven at end of
   948 calculations;
   949 
   950 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   951 method anyway;
   952 
   953 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   954 split_if split_if_asm; datatype package provides theorems foo.splits =
   955 foo.split foo.split_asm for each datatype;
   956 
   957 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   958 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   959 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   960 use "(cases (simplified))" method in proper proof texts);
   961 
   962 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   963 
   964 * Isar: names of theorems etc. may be natural numbers as well;
   965 
   966 * Isar: 'pr' command: optional arguments for goals_limit and
   967 ProofContext.prems_limit; no longer prints theory contexts, but only
   968 proof states;
   969 
   970 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   971 additional print modes to be specified; e.g. "pr(latex)" will print
   972 proof state according to the Isabelle LaTeX style;
   973 
   974 * Isar: improved support for emulating tactic scripts, including proof
   975 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   976 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   977 (for HOL datatypes);
   978 
   979 * Isar: simplified (more robust) goal selection of proof methods: 1st
   980 goal, all goals, or explicit goal specifier (tactic emulation); thus
   981 'proof method scripts' have to be in depth-first order;
   982 
   983 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   984 
   985 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   986 should instead use individual commands for printing items
   987 (print_commands, print_methods etc.);
   988 
   989 * Isar: added 'nothing' --- the empty list of theorems;
   990 
   991 
   992 *** HOL ***
   993 
   994 * HOL/MicroJava: formalization of a fragment of Java, together with a
   995 corresponding virtual machine and a specification of its bytecode
   996 verifier and a lightweight bytecode verifier, including proofs of
   997 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   998 Cornelia Pusch (see also the homepage of project Bali at
   999 http://isabelle.in.tum.de/Bali/);
  1000 
  1001 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1002 Clemens Ballarin;
  1003 
  1004 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1005 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1006 Rasmussen;
  1007 
  1008 * HOL/Lattice: fundamental concepts of lattice theory and order
  1009 structures, including duals, properties of bounds versus algebraic
  1010 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1011 Theorem for complete lattices etc.; may also serve as a demonstration
  1012 for abstract algebraic reasoning using axiomatic type classes, and
  1013 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1014 
  1015 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1016 von Oheimb;
  1017 
  1018 * HOL/IMPP: extension of IMP with local variables and mutually
  1019 recursive procedures, by David von Oheimb;
  1020 
  1021 * HOL/Lambda: converted into new-style theory and document;
  1022 
  1023 * HOL/ex/Multiquote: example of multiple nested quotations and
  1024 anti-quotations -- basically a generalized version of de-Bruijn
  1025 representation; very useful in avoiding lifting of operations;
  1026 
  1027 * HOL/record: added general record equality rule to simpset; fixed
  1028 select-update simplification procedure to handle extended records as
  1029 well; admit "r" as field name;
  1030 
  1031 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1032 other numeric types and also as the identity of groups, rings, etc.;
  1033 
  1034 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1035 Types nat and int belong to this axclass;
  1036 
  1037 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1038    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1039    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1040   two terms #m*u and #n*u are replaced by #(m+n)*u
  1041     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1042   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1043     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1044 
  1045 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1046 powerful prover for predicate logic but knows nothing of clasets; see
  1047 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1048 
  1049 * HOL: new version of "case_tac" subsumes both boolean case split and
  1050 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1051 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1052 
  1053 * HOL: simplification no longer dives into case-expressions: only the
  1054 selector expression is simplified, but not the remaining arms; to
  1055 enable full simplification of case-expressions for datatype t, you may
  1056 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1057 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1058 
  1059 * HOL/recdef: the recursion equations generated by 'recdef' for
  1060 function 'f' are now called f.simps instead of f.rules; if all
  1061 termination conditions are proved automatically, these simplification
  1062 rules are added to the simpset, as in primrec; rules may be named
  1063 individually as well, resulting in a separate list of theorems for
  1064 each equation;
  1065 
  1066 * HOL/While is a new theory that provides a while-combinator. It
  1067 permits the definition of tail-recursive functions without the
  1068 provision of a termination measure. The latter is necessary once the
  1069 invariant proof rule for while is applied.
  1070 
  1071 * HOL: new (overloaded) notation for the set of elements below/above
  1072 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1073 
  1074 * HOL: theorems impI, allI, ballI bound as "strip";
  1075 
  1076 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1077 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1078 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1079 
  1080 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1081 
  1082 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1083 main HOL, but was unused);
  1084 
  1085 * HOL: fewer consts declared as global (e.g. have to refer to
  1086 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1087 
  1088 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1089 in case of overlap with user translations (e.g. judgements over
  1090 tuples); (note that the underlying logical represenation is still
  1091 bogus);
  1092 
  1093 
  1094 *** ZF ***
  1095 
  1096 * ZF: simplification automatically cancels common terms in arithmetic
  1097 expressions over nat and int;
  1098 
  1099 * ZF: new treatment of nat to minimize type-checking: all operators
  1100 coerce their operands to a natural number using the function natify,
  1101 making the algebraic laws unconditional;
  1102 
  1103 * ZF: as above, for int: operators coerce their operands to an integer
  1104 using the function intify;
  1105 
  1106 * ZF: the integer library now contains many of the usual laws for the
  1107 orderings, including $<=, and monotonicity laws for $+ and $*;
  1108 
  1109 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1110 simplification;
  1111 
  1112 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1113 to the simplifier and classical reasoner simultaneously;
  1114 
  1115 
  1116 *** General ***
  1117 
  1118 * Provers: blast_tac now handles actual object-logic rules as
  1119 assumptions; note that auto_tac uses blast_tac internally as well;
  1120 
  1121 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1122 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1123 
  1124 * Provers: delrules now handles destruct rules as well (no longer need
  1125 explicit make_elim);
  1126 
  1127 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1128   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1129 use instead the strong form,
  1130   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1131 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1132 from destruct-rules;
  1133 
  1134 * Provers: Simplifier.easy_setup provides a fast path to basic
  1135 Simplifier setup for new object-logics;
  1136 
  1137 * Pure: AST translation rules no longer require constant head on LHS;
  1138 
  1139 * Pure: improved name spaces: ambiguous output is qualified; support
  1140 for hiding of names;
  1141 
  1142 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1143 XSYMBOL_HOME; no longer need to do manual configuration in most
  1144 situations;
  1145 
  1146 * system: compression of ML heaps images may now be controlled via -c
  1147 option of isabelle and isatool usedir (currently only observed by
  1148 Poly/ML);
  1149 
  1150 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1151 useful for remote X11);
  1152 
  1153 * system: provide TAGS file for Isabelle sources;
  1154 
  1155 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1156 order;
  1157 
  1158 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1159 timing flag supersedes proof_timing and Toplevel.trace;
  1160 
  1161 * ML: new combinators |>> and |>>> for incremental transformations
  1162 with secondary results (e.g. certain theory extensions):
  1163 
  1164 * ML: PureThy.add_defs gets additional argument to indicate potential
  1165 overloading (usually false);
  1166 
  1167 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1168 results;
  1169 
  1170 
  1171 
  1172 New in Isabelle99 (October 1999)
  1173 --------------------------------
  1174 
  1175 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1176 
  1177 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1178 are no longer simplified.  (This allows the simplifier to unfold recursive
  1179 functional programs.)  To restore the old behaviour, declare
  1180 
  1181     Delcongs [if_weak_cong];
  1182 
  1183 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1184 complement;
  1185 
  1186 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1187 
  1188 * HOL/datatype: mutual_induct_tac no longer exists --
  1189   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1190 
  1191 * HOL/typedef: fixed type inference for representing set; type
  1192 arguments now have to occur explicitly on the rhs as type constraints;
  1193 
  1194 * ZF: The con_defs part of an inductive definition may no longer refer
  1195 to constants declared in the same theory;
  1196 
  1197 * HOL, ZF: the function mk_cases, generated by the inductive
  1198 definition package, has lost an argument.  To simplify its result, it
  1199 uses the default simpset instead of a supplied list of theorems.
  1200 
  1201 * HOL/List: the constructors of type list are now Nil and Cons;
  1202 
  1203 * Simplifier: the type of the infix ML functions
  1204         setSSolver addSSolver setSolver addSolver
  1205 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1206 for packaging solvers. A solver is created via
  1207         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1208 where the string argument is only a comment.
  1209 
  1210 
  1211 *** Proof tools ***
  1212 
  1213 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1214 decision procedure for linear arithmetic. Currently it is used for
  1215 types `nat', `int', and `real' in HOL (see below); it can, should and
  1216 will be instantiated for other types and logics as well.
  1217 
  1218 * The simplifier now accepts rewrite rules with flexible heads, eg
  1219      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1220   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1221   matching.
  1222 
  1223 
  1224 *** General ***
  1225 
  1226 * New Isabelle/Isar subsystem provides an alternative to traditional
  1227 tactical theorem proving; together with the ProofGeneral/isar user
  1228 interface it offers an interactive environment for developing human
  1229 readable proof documents (Isar == Intelligible semi-automated
  1230 reasoning); for further information see isatool doc isar-ref,
  1231 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1232 
  1233 * improved and simplified presentation of theories: better HTML markup
  1234 (including colors), graph views in several sizes; isatool usedir now
  1235 provides a proper interface for user theories (via -P option); actual
  1236 document preparation based on (PDF)LaTeX is available as well (for
  1237 new-style theories only); see isatool doc system for more information;
  1238 
  1239 * native support for Proof General, both for classic Isabelle and
  1240 Isabelle/Isar;
  1241 
  1242 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1243 using the graph browser tool;
  1244 
  1245 * Isabelle manuals now also available as PDF;
  1246 
  1247 * theory loader rewritten from scratch (may not be fully
  1248 bug-compatible); old loadpath variable has been replaced by show_path,
  1249 add_path, del_path, reset_path functions; new operations such as
  1250 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1251 isatool doc ref);
  1252 
  1253 * improved isatool install: option -k creates KDE application icon,
  1254 option -p DIR installs standalone binaries;
  1255 
  1256 * added ML_PLATFORM setting (useful for cross-platform installations);
  1257 more robust handling of platform specific ML images for SML/NJ;
  1258 
  1259 * the settings environment is now statically scoped, i.e. it is never
  1260 created again in sub-processes invoked from isabelle, isatool, or
  1261 Isabelle;
  1262 
  1263 * path element specification '~~' refers to '$ISABELLE_HOME';
  1264 
  1265 * in locales, the "assumes" and "defines" parts may be omitted if
  1266 empty;
  1267 
  1268 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1269 long arrows);
  1270 
  1271 * new print_mode "HTML";
  1272 
  1273 * new flag show_tags controls display of tags of theorems (which are
  1274 basically just comments that may be attached by some tools);
  1275 
  1276 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1277 mode and goal output format:
  1278 
  1279 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1280 244c244
  1281 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1282 ---
  1283 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1284 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1285 181c181
  1286 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1287 ---
  1288 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1289 
  1290 * function bind_thms stores lists of theorems (cf. bind_thm);
  1291 
  1292 * new shorthand tactics ftac, eatac, datac, fatac;
  1293 
  1294 * qed (and friends) now accept "" as result name; in that case the
  1295 theorem is not stored, but proper checks and presentation of the
  1296 result still apply;
  1297 
  1298 * theorem database now also indexes constants "Trueprop", "all",
  1299 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1300 
  1301 
  1302 *** HOL ***
  1303 
  1304 ** HOL arithmetic **
  1305 
  1306 * There are now decision procedures for linear arithmetic over nat and
  1307 int:
  1308 
  1309 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1310 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1311 are treated as atomic; subformulae not involving type `nat' or `int'
  1312 are ignored; quantified subformulae are ignored unless they are
  1313 positive universal or negative existential. The tactic has to be
  1314 invoked by hand and can be a little bit slow. In particular, the
  1315 running time is exponential in the number of occurrences of `min' and
  1316 `max', and `-' on `nat'.
  1317 
  1318 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1319 (negated) (in)equalities among the premises and the conclusion into
  1320 account (i.e. no compound formulae) and does not know about `min' and
  1321 `max', and `-' on `nat'. It is fast and is used automatically by the
  1322 simplifier.
  1323 
  1324 NB: At the moment, these decision procedures do not cope with mixed
  1325 nat/int formulae where the two parts interact, such as `m < n ==>
  1326 int(m) < int(n)'.
  1327 
  1328 * HOL/Numeral provides a generic theory of numerals (encoded
  1329 efficiently as bit strings); setup for types nat/int/real is in place;
  1330 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1331 int, existing theories and proof scripts may require a few additional
  1332 type constraints;
  1333 
  1334 * integer division and remainder can now be performed on constant
  1335 arguments;
  1336 
  1337 * many properties of integer multiplication, division and remainder
  1338 are now available;
  1339 
  1340 * An interface to the Stanford Validity Checker (SVC) is available through the
  1341 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1342 are proved automatically.  SVC must be installed separately, and its results
  1343 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1344 invocation of the underlying oracle).  For SVC see
  1345   http://verify.stanford.edu/SVC
  1346 
  1347 * IsaMakefile: the HOL-Real target now builds an actual image;
  1348 
  1349 
  1350 ** HOL misc **
  1351 
  1352 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1353 (in Isabelle/Isar) -- by Gertrud Bauer;
  1354 
  1355 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1356 analysis for assembly languages with subtypes;
  1357 
  1358 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1359 -- avoids syntactic ambiguities and treats state, transition, and
  1360 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1361 changed syntax and (many) tactics;
  1362 
  1363 * HOL/inductive: Now also handles more general introduction rules such
  1364   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1365   theorems are now maintained within the theory (maintained via the
  1366   "mono" attribute);
  1367 
  1368 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1369   (using function types) such as
  1370 
  1371   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1372 
  1373 * HOL/record: record_simproc (part of the default simpset) takes care
  1374 of selectors applied to updated records; record_split_tac is no longer
  1375 part of the default claset; update_defs may now be removed from the
  1376 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1377 
  1378   claset_ref () := claset() addSWrapper record_split_wrapper;
  1379   Delsimprocs [record_simproc]
  1380 
  1381 * HOL/typedef: fixed type inference for representing set; type
  1382 arguments now have to occur explicitly on the rhs as type constraints;
  1383 
  1384 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1385 names rather than an ML expression;
  1386 
  1387 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1388 supplied later.  Program schemes can be defined, such as
  1389     "While B C s = (if B s then While B C (C s) else s)"
  1390 where the well-founded relation can be chosen after B and C have been given.
  1391 
  1392 * HOL/List: the constructors of type list are now Nil and Cons;
  1393 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1394 course, ML tools referring to List.list.op # etc. have to be adapted;
  1395 
  1396 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1397 disabled by default; run isabelle with option -m HOL to get back to
  1398 the original Gordon/HOL-style output;
  1399 
  1400 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1401 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1402 
  1403 * HOL basic syntax simplified (more orthogonal): all variants of
  1404 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1405 Eps operator is provided as well: "SOME x. P[x]";
  1406 
  1407 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1408 
  1409 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1410 thus available for user theories;
  1411 
  1412 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1413 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1414 time;
  1415 
  1416 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1417 several times and then mp;
  1418 
  1419 
  1420 *** LK ***
  1421 
  1422 * the notation <<...>> is now available as a notation for sequences of
  1423 formulas;
  1424 
  1425 * the simplifier is now installed
  1426 
  1427 * the axiom system has been generalized (thanks to Soren Heilmann)
  1428 
  1429 * the classical reasoner now has a default rule database
  1430 
  1431 
  1432 *** ZF ***
  1433 
  1434 * new primrec section allows primitive recursive functions to be given
  1435 directly (as in HOL) over datatypes and the natural numbers;
  1436 
  1437 * new tactics induct_tac and exhaust_tac for induction (or case
  1438 analysis) over datatypes and the natural numbers;
  1439 
  1440 * the datatype declaration of type T now defines the recursor T_rec;
  1441 
  1442 * simplification automatically does freeness reasoning for datatype
  1443 constructors;
  1444 
  1445 * automatic type-inference, with AddTCs command to insert new
  1446 type-checking rules;
  1447 
  1448 * datatype introduction rules are now added as Safe Introduction rules
  1449 to the claset;
  1450 
  1451 * the syntax "if P then x else y" is now available in addition to
  1452 if(P,x,y);
  1453 
  1454 
  1455 *** Internal programming interfaces ***
  1456 
  1457 * tuned simplifier trace output; new flag debug_simp;
  1458 
  1459 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1460 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1461 
  1462 * AxClass.axclass_tac lost the theory argument;
  1463 
  1464 * tuned current_goals_markers semantics: begin / end goal avoids
  1465 printing empty lines;
  1466 
  1467 * removed prs and prs_fn hook, which was broken because it did not
  1468 include \n in its semantics, forcing writeln to add one
  1469 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1470 string -> unit if you really want to output text without newline;
  1471 
  1472 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1473 plain output, interface builders may have to enable 'isabelle_font'
  1474 mode to get Isabelle font glyphs as before;
  1475 
  1476 * refined token_translation interface; INCOMPATIBILITY: output length
  1477 now of type real instead of int;
  1478 
  1479 * theory loader actions may be traced via new ThyInfo.add_hook
  1480 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1481 your own database of information attached to *whole* theories -- as
  1482 opposed to intra-theory data slots offered via TheoryDataFun;
  1483 
  1484 * proper handling of dangling sort hypotheses (at last!);
  1485 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1486 extra sort hypotheses that can be witnessed from the type signature;
  1487 the force_strip_shyps flag is gone, any remaining shyps are simply
  1488 left in the theorem (with a warning issued by strip_shyps_warning);
  1489 
  1490 
  1491 
  1492 New in Isabelle98-1 (October 1998)
  1493 ----------------------------------
  1494 
  1495 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1496 
  1497 * several changes of automated proof tools;
  1498 
  1499 * HOL: major changes to the inductive and datatype packages, including
  1500 some minor incompatibilities of theory syntax;
  1501 
  1502 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1503 called `inj_on';
  1504 
  1505 * HOL: removed duplicate thms in Arith:
  1506   less_imp_add_less  should be replaced by  trans_less_add1
  1507   le_imp_add_le      should be replaced by  trans_le_add1
  1508 
  1509 * HOL: unary minus is now overloaded (new type constraints may be
  1510 required);
  1511 
  1512 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1513 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1514 now taken as an integer constant.
  1515 
  1516 * Pure: ML function 'theory_of' renamed to 'theory';
  1517 
  1518 
  1519 *** Proof tools ***
  1520 
  1521 * Simplifier:
  1522   1. Asm_full_simp_tac is now more aggressive.
  1523      1. It will sometimes reorient premises if that increases their power to
  1524         simplify.
  1525      2. It does no longer proceed strictly from left to right but may also
  1526         rotate premises to achieve further simplification.
  1527      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1528      old Asm_full_simp_tac in that it does not rotate premises.
  1529   2. The simplifier now knows a little bit about nat-arithmetic.
  1530 
  1531 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1532 allows for selected deletion of wrappers, by introduction of names for
  1533 wrapper functionals.  This implies that addbefore, addSbefore,
  1534 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1535 and that adding two tactics with the same name overwrites the first
  1536 one (emitting a warning).
  1537   type wrapper = (int -> tactic) -> (int -> tactic)
  1538   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1539   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1540   delWrapper, delSWrapper: claset *  string            -> claset
  1541   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1542 
  1543 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1544 semantics; addbefore now affects only the unsafe part of step_tac
  1545 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1546 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1547 by Force_tac;
  1548 
  1549 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1550 compWrapper; added safe wrapper (and access functions for it);
  1551 
  1552 * HOL/split_all_tac is now much faster and fails if there is nothing
  1553 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1554 and the names of the automatically generated variables have changed.
  1555 split_all_tac has moved within claset() from unsafe wrappers to safe
  1556 wrappers, which means that !!-bound variables are split much more
  1557 aggressively, and safe_tac and clarify_tac now split such variables.
  1558 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1559 Note: the same holds for record_split_tac, which does the job of
  1560 split_all_tac for record fields.
  1561 
  1562 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1563 permanently to the default simpset using Addsplits just like
  1564 Addsimps. They can be removed via Delsplits just like
  1565 Delsimps. Lower-case versions are also available.
  1566 
  1567 * HOL/Simplifier: The rule split_if is now part of the default
  1568 simpset. This means that the simplifier will eliminate all occurrences
  1569 of if-then-else in the conclusion of a goal. To prevent this, you can
  1570 either remove split_if completely from the default simpset by
  1571 `Delsplits [split_if]' or remove it in a specific call of the
  1572 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1573 other case splitting rules to/from the default simpset: every datatype
  1574 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1575 t is the name of the datatype).
  1576 
  1577 * Classical reasoner / Simplifier combination: new force_tac (and
  1578 derivatives Force_tac, force) combines rewriting and classical
  1579 reasoning (and whatever other tools) similarly to auto_tac, but is
  1580 aimed to solve the given subgoal completely.
  1581 
  1582 
  1583 *** General ***
  1584 
  1585 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1586 and `goalw': the theory is no longer needed as an explicit argument -
  1587 the current theory context is used; assumptions are no longer returned
  1588 at the ML-level unless one of them starts with ==> or !!; it is
  1589 recommended to convert to these new commands using isatool fixgoal
  1590 (backup your sources first!);
  1591 
  1592 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1593 the current theory context, and 'theory' to lookup stored theories;
  1594 
  1595 * new theory section 'locale' for declaring constants, assumptions and
  1596 definitions that have local scope;
  1597 
  1598 * new theory section 'nonterminals' for purely syntactic types;
  1599 
  1600 * new theory section 'setup' for generic ML setup functions
  1601 (e.g. package initialization);
  1602 
  1603 * the distribution now includes Isabelle icons: see
  1604 lib/logo/isabelle-{small,tiny}.xpm;
  1605 
  1606 * isatool install - install binaries with absolute references to
  1607 ISABELLE_HOME/bin;
  1608 
  1609 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1610 
  1611 * print mode 'emacs' reserved for Isamode;
  1612 
  1613 * support multiple print (ast) translations per constant name;
  1614 
  1615 * theorems involving oracles are now printed with a suffixed [!];
  1616 
  1617 
  1618 *** HOL ***
  1619 
  1620 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1621 
  1622 * HOL/inductive package reorganized and improved: now supports mutual
  1623 definitions such as
  1624 
  1625   inductive EVEN ODD
  1626     intrs
  1627       null "0 : EVEN"
  1628       oddI "n : EVEN ==> Suc n : ODD"
  1629       evenI "n : ODD ==> Suc n : EVEN"
  1630 
  1631 new theorem list "elims" contains an elimination rule for each of the
  1632 recursive sets; inductive definitions now handle disjunctive premises
  1633 correctly (also ZF);
  1634 
  1635 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1636 "mutual_induct" no longer exists - the induction rule is always
  1637 contained in "induct";
  1638 
  1639 
  1640 * HOL/datatype package re-implemented and greatly improved: now
  1641 supports mutually recursive datatypes such as
  1642 
  1643   datatype
  1644     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1645             | SUM ('a aexp) ('a aexp)
  1646             | DIFF ('a aexp) ('a aexp)
  1647             | NUM 'a
  1648   and
  1649     'a bexp = LESS ('a aexp) ('a aexp)
  1650             | AND ('a bexp) ('a bexp)
  1651             | OR ('a bexp) ('a bexp)
  1652 
  1653 as well as indirectly recursive datatypes such as
  1654 
  1655   datatype
  1656     ('a, 'b) term = Var 'a
  1657                   | App 'b ((('a, 'b) term) list)
  1658 
  1659 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1660 induction on mutually / indirectly recursive datatypes.
  1661 
  1662 Primrec equations are now stored in theory and can be accessed via
  1663 <function_name>.simps.
  1664 
  1665 INCOMPATIBILITIES:
  1666 
  1667   - Theories using datatypes must now have theory Datatype as an
  1668     ancestor.
  1669   - The specific <typename>.induct_tac no longer exists - use the
  1670     generic induct_tac instead.
  1671   - natE has been renamed to nat.exhaust - use exhaust_tac
  1672     instead of res_inst_tac ... natE. Note that the variable
  1673     names in nat.exhaust differ from the names in natE, this
  1674     may cause some "fragile" proofs to fail.
  1675   - The theorems split_<typename>_case and split_<typename>_case_asm
  1676     have been renamed to <typename>.split and <typename>.split_asm.
  1677   - Since default sorts of type variables are now handled correctly,
  1678     some datatype definitions may have to be annotated with explicit
  1679     sort constraints.
  1680   - Primrec definitions no longer require function name and type
  1681     of recursive argument.
  1682 
  1683 Consider using isatool fixdatatype to adapt your theories and proof
  1684 scripts to the new package (backup your sources first!).
  1685 
  1686 
  1687 * HOL/record package: considerably improved implementation; now
  1688 includes concrete syntax for record types, terms, updates; theorems
  1689 for surjective pairing and splitting !!-bound record variables; proof
  1690 support is as follows:
  1691 
  1692   1) standard conversions (selectors or updates applied to record
  1693 constructor terms) are part of the standard simpset;
  1694 
  1695   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1696 made part of standard simpset and claset via addIffs;
  1697 
  1698   3) a tactic for record field splitting (record_split_tac) is part of
  1699 the standard claset (addSWrapper);
  1700 
  1701 To get a better idea about these rules you may retrieve them via
  1702 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1703 the name of your record type.
  1704 
  1705 The split tactic 3) conceptually simplifies by the following rule:
  1706 
  1707   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1708 
  1709 Thus any record variable that is bound by meta-all will automatically
  1710 blow up into some record constructor term, consequently the
  1711 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1712 solve record problems automatically.
  1713 
  1714 
  1715 * reorganized the main HOL image: HOL/Integ and String loaded by
  1716 default; theory Main includes everything;
  1717 
  1718 * automatic simplification of integer sums and comparisons, using cancellation;
  1719 
  1720 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1721 
  1722 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1723 
  1724 * many new identities for unions, intersections, set difference, etc.;
  1725 
  1726 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1727 called split_if, split_split, split_sum_case and split_nat_case (to go
  1728 with add/delsplits);
  1729 
  1730 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1731 (?x::unit) = (); this is made part of the default simpset, which COULD
  1732 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1733 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1734 unit_abs_eta_conv is added in order to counter the effect of
  1735 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1736 %u.f();
  1737 
  1738 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1739 makes more sense);
  1740 
  1741 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1742   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1743   disjointness reasoning but breaking a few old proofs.
  1744 
  1745 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1746 to 'converse' from 'inverse' (for compatibility with ZF and some
  1747 literature);
  1748 
  1749 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1750 the well-founded relation;
  1751 
  1752 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1753     Compl A.  The "Compl" syntax remains available as input syntax for this
  1754     release ONLY.
  1755 
  1756 * HOL/Update: new theory of function updates:
  1757     f(a:=b) == %x. if x=a then b else f x
  1758 may also be iterated as in f(a:=b,c:=d,...);
  1759 
  1760 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1761 
  1762 * HOL/List:
  1763   - new function list_update written xs[i:=v] that updates the i-th
  1764     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1765   - new function `upt' written [i..j(] which generates the list
  1766     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1767     bound write [i..j], which is a shorthand for [i..j+1(].
  1768   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1769 
  1770 * HOL/Arith:
  1771   - removed 'pred' (predecessor) function;
  1772   - generalized some theorems about n-1;
  1773   - many new laws about "div" and "mod";
  1774   - new laws about greatest common divisors (see theory ex/Primes);
  1775 
  1776 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1777 instead of "inverse";
  1778 
  1779 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1780   of the multiset ordering;
  1781 
  1782 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1783   (not included by default);
  1784 
  1785 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1786 
  1787 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1788   programs, i.e. different program variables may have different types.
  1789 
  1790 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1791   [previously, this check worked only if the rewrite rule was unconditional]
  1792   Now rew can involve either definitions or equalities (either == or =).
  1793 
  1794 
  1795 *** ZF ***
  1796 
  1797 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1798   only the theorems proved on ZF.ML;
  1799 
  1800 * ZF 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 * ZF/Update: new theory of function updates
  1805     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1806   may also be iterated as in f(a:=b,c:=d,...);
  1807 
  1808 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1809 
  1810 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1811   [previously, this check worked only if the rewrite rule was unconditional]
  1812   Now rew can involve either definitions or equalities (either == or =).
  1813 
  1814 * case_tac provided for compatibility with HOL
  1815     (like the old excluded_middle_tac, but with subgoals swapped)
  1816 
  1817 
  1818 *** Internal programming interfaces ***
  1819 
  1820 * Pure: several new basic modules made available for general use, see
  1821 also src/Pure/README;
  1822 
  1823 * improved the theory data mechanism to support encapsulation (data
  1824 kind name replaced by private Object.kind, acting as authorization
  1825 key); new type-safe user interface via functor TheoryDataFun; generic
  1826 print_data function becomes basically useless;
  1827 
  1828 * removed global_names compatibility flag -- all theory declarations
  1829 are qualified by default;
  1830 
  1831 * module Pure/Syntax now offers quote / antiquote translation
  1832 functions (useful for Hoare logic etc. with implicit dependencies);
  1833 see HOL/ex/Antiquote for an example use;
  1834 
  1835 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1836 cterm -> thm;
  1837 
  1838 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1839 subgoal;
  1840 
  1841 * Display.print_goals function moved to Locale.print_goals;
  1842 
  1843 * standard print function for goals supports current_goals_markers
  1844 variable for marking begin of proof, end of proof, start of goal; the
  1845 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1846 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1847 for example;
  1848 
  1849 
  1850 
  1851 New in Isabelle98 (January 1998)
  1852 --------------------------------
  1853 
  1854 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1855 
  1856 * changed lexical syntax of terms / types: dots made part of long
  1857 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1858 
  1859 * simpset (and claset) reference variable replaced by functions
  1860 simpset / simpset_ref;
  1861 
  1862 * no longer supports theory aliases (via merge) and non-trivial
  1863 implicit merge of thms' signatures;
  1864 
  1865 * most internal names of constants changed due to qualified names;
  1866 
  1867 * changed Pure/Sequence interface (see Pure/seq.ML);
  1868 
  1869 
  1870 *** General Changes ***
  1871 
  1872 * hierachically structured name spaces (for consts, types, axms, thms
  1873 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1874 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1875 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1876 long_names for fully qualified output names; NOTE: ML programs
  1877 (special tactics, packages etc.) referring to internal names may have
  1878 to be adapted to cope with fully qualified names; in case of severe
  1879 backward campatibility problems try setting 'global_names' at compile
  1880 time to have enrything declared within a flat name space; one may also
  1881 fine tune name declarations in theories via the 'global' and 'local'
  1882 section;
  1883 
  1884 * reimplemented the implicit simpset and claset using the new anytype
  1885 data filed in signatures; references simpset:simpset ref etc. are
  1886 replaced by functions simpset:unit->simpset and
  1887 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1888 to patch your ML files accordingly;
  1889 
  1890 * HTML output now includes theory graph data for display with Java
  1891 applet or isatool browser; data generated automatically via isatool
  1892 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1893 
  1894 * defs may now be conditional; improved rewrite_goals_tac to handle
  1895 conditional equations;
  1896 
  1897 * defs now admits additional type arguments, using TYPE('a) syntax;
  1898 
  1899 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1900 creates a new theory node; implicit merge of thms' signatures is
  1901 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1902 transfer:theory->thm->thm in (rare) cases;
  1903 
  1904 * improved handling of draft signatures / theories; draft thms (and
  1905 ctyps, cterms) are automatically promoted to real ones;
  1906 
  1907 * slightly changed interfaces for oracles: admit many per theory, named
  1908 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1909 
  1910 * print_goals: optional output of const types (set show_consts and
  1911 show_types);
  1912 
  1913 * improved output of warnings (###) and errors (***);
  1914 
  1915 * subgoal_tac displays a warning if the new subgoal has type variables;
  1916 
  1917 * removed old README and Makefiles;
  1918 
  1919 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1920 
  1921 * removed obsolete init_pps and init_database;
  1922 
  1923 * deleted the obsolete tactical STATE, which was declared by
  1924     fun STATE tacfun st = tacfun st st;
  1925 
  1926 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1927 (which abbreviates $HOME);
  1928 
  1929 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1930 use isatool fixseq to adapt your ML programs (this works for fully
  1931 qualified references to the Sequence structure only!);
  1932 
  1933 * use_thy no longer requires writable current directory; it always
  1934 reloads .ML *and* .thy file, if either one is out of date;
  1935 
  1936 
  1937 *** Classical Reasoner ***
  1938 
  1939 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1940 tactics that use classical reasoning to simplify a subgoal without
  1941 splitting it into several subgoals;
  1942 
  1943 * Safe_tac: like safe_tac but uses the default claset;
  1944 
  1945 
  1946 *** Simplifier ***
  1947 
  1948 * added simplification meta rules:
  1949     (asm_)(full_)simplify: simpset -> thm -> thm;
  1950 
  1951 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1952 logics (again);
  1953 
  1954 * added prems argument to simplification procedures;
  1955 
  1956 * HOL, FOL, ZF: added infix function `addsplits':
  1957   instead of `<simpset> setloop (split_tac <thms>)'
  1958   you can simply write `<simpset> addsplits <thms>'
  1959 
  1960 
  1961 *** Syntax ***
  1962 
  1963 * TYPE('a) syntax for type reflection terms;
  1964 
  1965 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1966 
  1967 * pretty printer: changed order of mixfix annotation preference (again!);
  1968 
  1969 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1970 
  1971 
  1972 *** HOL ***
  1973 
  1974 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1975   with `addloop' of the simplifier to faciliate case splitting in premises.
  1976 
  1977 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1978 
  1979 * HOL/Auth: new protocol proofs including some for the Internet
  1980   protocol TLS;
  1981 
  1982 * HOL/Map: new theory of `maps' a la VDM;
  1983 
  1984 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1985 cancelling out common nat summands from =, <, <= (in)equalities, or
  1986 differences; simplification procedures nat_cancel_factor for
  1987 cancelling common factor from =, <, <= (in)equalities over natural
  1988 sums; nat_cancel contains both kinds of procedures, it is installed by
  1989 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1990 
  1991 * HOL/simplifier: terms of the form
  1992   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1993   are rewritten to
  1994   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1995   and those of the form
  1996   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1997   are rewritten to
  1998   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1999 
  2000 * HOL/datatype
  2001   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2002 
  2003   P(t_case f1 ... fn x) =
  2004      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2005         ...
  2006        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2007      )
  2008 
  2009   and a theorem `split_t_case_asm' of the form
  2010 
  2011   P(t_case f1 ... fn x) =
  2012     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2013         ...
  2014        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2015      )
  2016   which can be added to a simpset via `addsplits'. The existing theorems
  2017   expand_list_case and expand_option_case have been renamed to
  2018   split_list_case and split_option_case.
  2019 
  2020 * HOL/Arithmetic:
  2021   - `pred n' is automatically converted to `n-1'.
  2022     Users are strongly encouraged not to use `pred' any longer,
  2023     because it will disappear altogether at some point.
  2024   - Users are strongly encouraged to write "0 < n" rather than
  2025     "n ~= 0". Theorems and proof tools have been modified towards this
  2026     `standard'.
  2027 
  2028 * HOL/Lists:
  2029   the function "set_of_list" has been renamed "set" (and its theorems too);
  2030   the function "nth" now takes its arguments in the reverse order and
  2031   has acquired the infix notation "!" as in "xs!n".
  2032 
  2033 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2034 
  2035 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2036   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2037 
  2038 * HOL/record: extensible records with schematic structural subtyping
  2039 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2040 still lacks various theorems and concrete record syntax;
  2041 
  2042 
  2043 *** HOLCF ***
  2044 
  2045 * removed "axioms" and "generated by" sections;
  2046 
  2047 * replaced "ops" section by extended "consts" section, which is capable of
  2048   handling the continuous function space "->" directly;
  2049 
  2050 * domain package:
  2051   . proves theorems immediately and stores them in the theory,
  2052   . creates hierachical name space,
  2053   . now uses normal mixfix annotations (instead of cinfix...),
  2054   . minor changes to some names and values (for consistency),
  2055   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2056   . separator between mutual domain defs: changed "," to "and",
  2057   . improved handling of sort constraints;  now they have to
  2058     appear on the left-hand side of the equations only;
  2059 
  2060 * fixed LAM <x,y,zs>.b syntax;
  2061 
  2062 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2063 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2064 
  2065 
  2066 *** FOL and ZF ***
  2067 
  2068 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2069   with `addloop' of the simplifier to faciliate case splitting in premises.
  2070 
  2071 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2072 in HOL, they strip ALL and --> from proved theorems;
  2073 
  2074 
  2075 
  2076 New in Isabelle94-8 (May 1997)
  2077 ------------------------------
  2078 
  2079 *** General Changes ***
  2080 
  2081 * new utilities to build / run / maintain Isabelle etc. (in parts
  2082 still somewhat experimental); old Makefiles etc. still functional;
  2083 
  2084 * new 'Isabelle System Manual';
  2085 
  2086 * INSTALL text, together with ./configure and ./build scripts;
  2087 
  2088 * reimplemented type inference for greater efficiency, better error
  2089 messages and clean internal interface;
  2090 
  2091 * prlim command for dealing with lots of subgoals (an easier way of
  2092 setting goals_limit);
  2093 
  2094 
  2095 *** Syntax ***
  2096 
  2097 * supports alternative (named) syntax tables (parser and pretty
  2098 printer); internal interface is provided by add_modesyntax(_i);
  2099 
  2100 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2101 be used in conjunction with the Isabelle symbol font; uses the
  2102 "symbols" syntax table;
  2103 
  2104 * added token_translation interface (may translate name tokens in
  2105 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2106 the current print_mode); IMPORTANT: user print translation functions
  2107 are responsible for marking newly introduced bounds
  2108 (Syntax.mark_boundT);
  2109 
  2110 * token translations for modes "xterm" and "xterm_color" that display
  2111 names in bold, underline etc. or colors (which requires a color
  2112 version of xterm);
  2113 
  2114 * infixes may now be declared with names independent of their syntax;
  2115 
  2116 * added typed_print_translation (like print_translation, but may
  2117 access type of constant);
  2118 
  2119 
  2120 *** Classical Reasoner ***
  2121 
  2122 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2123 some limitations.  Blast_tac...
  2124   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2125   + ignores elimination rules that don't have the correct format
  2126         (the conclusion MUST be a formula variable)
  2127   + ignores types, which can make HOL proofs fail
  2128   + rules must not require higher-order unification, e.g. apply_type in ZF
  2129     [message "Function Var's argument not a bound variable" relates to this]
  2130   + its proof strategy is more general but can actually be slower
  2131 
  2132 * substitution with equality assumptions no longer permutes other
  2133 assumptions;
  2134 
  2135 * minor changes in semantics of addafter (now called addaltern); renamed
  2136 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2137 (and access functions for it);
  2138 
  2139 * improved combination of classical reasoner and simplifier:
  2140   + functions for handling clasimpsets
  2141   + improvement of addss: now the simplifier is called _after_ the
  2142     safe steps.
  2143   + safe variant of addss called addSss: uses safe simplifications
  2144     _during_ the safe steps. It is more complete as it allows multiple
  2145     instantiations of unknowns (e.g. with slow_tac).
  2146 
  2147 *** Simplifier ***
  2148 
  2149 * added interface for simplification procedures (functions that
  2150 produce *proven* rewrite rules on the fly, depending on current
  2151 redex);
  2152 
  2153 * ordering on terms as parameter (used for ordered rewriting);
  2154 
  2155 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2156 
  2157 * the solver is now split into a safe and an unsafe part.
  2158 This should be invisible for the normal user, except that the
  2159 functions setsolver and addsolver have been renamed to setSolver and
  2160 addSolver; added safe_asm_full_simp_tac;
  2161 
  2162 
  2163 *** HOL ***
  2164 
  2165 * a generic induction tactic `induct_tac' which works for all datatypes and
  2166 also for type `nat';
  2167 
  2168 * a generic case distinction tactic `exhaust_tac' which works for all
  2169 datatypes and also for type `nat';
  2170 
  2171 * each datatype comes with a function `size';
  2172 
  2173 * patterns in case expressions allow tuple patterns as arguments to
  2174 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2175 
  2176 * primrec now also works with type nat;
  2177 
  2178 * recdef: a new declaration form, allows general recursive functions to be
  2179 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2180 
  2181 * the constant for negation has been renamed from "not" to "Not" to
  2182 harmonize with FOL, ZF, LK, etc.;
  2183 
  2184 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2185 infinite lists;
  2186 
  2187 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2188 
  2189 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2190 problems in commutative rings, using axiomatic type classes for + and *;
  2191 
  2192 * more examples in HOL/MiniML and HOL/Auth;
  2193 
  2194 * more default rewrite rules for quantifiers, union/intersection;
  2195 
  2196 * a new constant `arbitrary == @x.False';
  2197 
  2198 * HOLCF/IOA replaces old HOL/IOA;
  2199 
  2200 * HOLCF changes: derived all rules and arities
  2201   + axiomatic type classes instead of classes
  2202   + typedef instead of faking type definitions
  2203   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2204   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2205   + eliminated the types void, one, tr
  2206   + use unit lift and bool lift (with translations) instead of one and tr
  2207   + eliminated blift from Lift3.thy (use Def instead of blift)
  2208   all eliminated rules are derived as theorems --> no visible changes ;
  2209 
  2210 
  2211 *** ZF ***
  2212 
  2213 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2214 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2215 as ZF_cs addSIs [equalityI];
  2216 
  2217 
  2218 
  2219 New in Isabelle94-7 (November 96)
  2220 ---------------------------------
  2221 
  2222 * allowing negative levels (as offsets) in prlev and choplev;
  2223 
  2224 * super-linear speedup for large simplifications;
  2225 
  2226 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2227 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2228 FAIL); can suppress it using the command Delsimps (ex_simps @
  2229 all_simps); De Morgan laws are also now included, by default;
  2230 
  2231 * improved printing of ==>  :  ~:
  2232 
  2233 * new object-logic "Sequents" adds linear logic, while replacing LK
  2234 and Modal (thanks to Sara Kalvala);
  2235 
  2236 * HOL/Auth: correctness proofs for authentication protocols;
  2237 
  2238 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2239 examples on HOL/Auth);
  2240 
  2241 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2242 the rewriter and classical reasoner simultaneously;
  2243 
  2244 * function uresult no longer returns theorems in "standard" format;
  2245 regain previous version by: val uresult = standard o uresult;
  2246 
  2247 
  2248 
  2249 New in Isabelle94-6
  2250 -------------------
  2251 
  2252 * oracles -- these establish an interface between Isabelle and trusted
  2253 external reasoners, which may deliver results as theorems;
  2254 
  2255 * proof objects (in particular record all uses of oracles);
  2256 
  2257 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2258 
  2259 * "constdefs" section in theory files;
  2260 
  2261 * "primrec" section (HOL) no longer requires names;
  2262 
  2263 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2264 
  2265 
  2266 
  2267 New in Isabelle94-5
  2268 -------------------
  2269 
  2270 * reduced space requirements;
  2271 
  2272 * automatic HTML generation from theories;
  2273 
  2274 * theory files no longer require "..." (quotes) around most types;
  2275 
  2276 * new examples, including two proofs of the Church-Rosser theorem;
  2277 
  2278 * non-curried (1994) version of HOL is no longer distributed;
  2279 
  2280 
  2281 
  2282 New in Isabelle94-4
  2283 -------------------
  2284 
  2285 * greatly reduced space requirements;
  2286 
  2287 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2288 
  2289 * searchable theorem database (see the section "Retrieving theorems" on
  2290 page 8 of the Reference Manual);
  2291 
  2292 * new examples, including Grabczewski's monumental case study of the
  2293 Axiom of Choice;
  2294 
  2295 * The previous version of HOL renamed to Old_HOL;
  2296 
  2297 * The new version of HOL (previously called CHOL) uses a curried syntax
  2298 for functions.  Application looks like f a b instead of f(a,b);
  2299 
  2300 * Mutually recursive inductive definitions finally work in HOL;
  2301 
  2302 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2303 translates to the operator "split";
  2304 
  2305 
  2306 
  2307 New in Isabelle94-3
  2308 -------------------
  2309 
  2310 * new infix operator, addss, allowing the classical reasoner to
  2311 perform simplification at each step of its search.  Example:
  2312         fast_tac (cs addss ss)
  2313 
  2314 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2315 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2316 look like (a,b) instead of <a,b>;
  2317 
  2318 * PLEASE NOTE: CHOL will eventually replace HOL!
  2319 
  2320 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2321 It translates to the operator "split".  A new theory of integers is available;
  2322 
  2323 * In ZF, integer numerals now denote two's-complement binary integers.
  2324 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2325 
  2326 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2327 of the Axiom of Choice;
  2328 
  2329 
  2330 
  2331 New in Isabelle94-2
  2332 -------------------
  2333 
  2334 * Significantly faster resolution;
  2335 
  2336 * the different sections in a .thy file can now be mixed and repeated
  2337 freely;
  2338 
  2339 * Database of theorems for FOL, HOL and ZF.  New
  2340 commands including qed, qed_goal and bind_thm store theorems in the database.
  2341 
  2342 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2343 a given theory (thms_of), or find out what theory a theorem was proved in
  2344 (theory_of_thm);
  2345 
  2346 * Bugs fixed in the inductive definition and datatype packages;
  2347 
  2348 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2349 and HOL_dup_cs obsolete;
  2350 
  2351 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2352 have been removed;
  2353 
  2354 * Simpler definition of function space in ZF;
  2355 
  2356 * new results about cardinal and ordinal arithmetic in ZF;
  2357 
  2358 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2359 types;
  2360 
  2361 
  2362 $Id$