NEWS
author wenzelm
Sun Feb 04 19:40:06 2001 +0100 (2001-02-04)
changeset 11050 ac5709ac50b9
parent 11043 2e3bbac8763b
child 11062 e86340dc1d28
permissions -rw-r--r--
* no_document ML operator temporarily disables LaTeX document
generation;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 *** Overview of INCOMPATIBILITIES ***
     6 
     7 * HOL: inductive package no longer splits induction rule aggressively,
     8 but only as far as specified by the introductions given; the old
     9 format may recovered via ML function complete_split_rule or attribute
    10 'split_rule (complete)';
    11 
    12 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
    13 gfp_Tarski to gfp_unfold;
    14 
    15 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    16 
    17 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    18 relation); infix "^^" has been renamed "``"; infix "``" has been
    19 renamed "`"; "univalent" has been renamed "single_valued";
    20 
    21 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    22 operation;
    23 
    24 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    25 
    26 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    27 
    28 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    29 consequence, it is no longer monotonic wrt. the local goal context
    30 (which is now passed through the inductive cases);
    31 
    32 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    33 \<gg> to \<ggreater>;
    34 
    35 
    36 *** Document preparation ***
    37 
    38 * \isabellestyle{NAME} selects version of Isabelle output (currently
    39 available: are "it" for near math-mode best-style output, "sl" for
    40 slanted text style, and "tt" for plain type-writer; if no
    41 \isabellestyle command is given, output is according to slanted
    42 type-writer);
    43 
    44 * support sub/super scripts (for single symbols only), input syntax is
    45 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    46 
    47 * some more standard symbols; see Appendix A of the system manual for
    48 the complete list;
    49 
    50 * improved isabelle style files; more abstract symbol implementation
    51 (should now use \isamath{...} and \isatext{...} in custom symbol
    52 definitions);
    53 
    54 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    55 state; Note that presentation of goal states does not conform to
    56 actual human-readable proof documents.  Please do not include goal
    57 states into document output unless you really know what you are doing!
    58 
    59 * isatool unsymbolize tunes sources for plain ASCII communication;
    60 
    61 * no_document ML operator temporarily disables LaTeX document
    62 generation;
    63 
    64 
    65 *** Isar ***
    66 
    67 * Pure: Isar now suffers initial goal statements to contain unbound
    68 schematic variables (this does not conform to actual readable proof
    69 documents, due to unpredictable outcome and non-compositional proof
    70 checking); users who know what they are doing may use schematic goals
    71 for Prolog-style synthesis of proven results;
    72 
    73 * Pure: assumption method (an implicit finishing) now handles actual
    74 rules as well;
    75 
    76 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    77 initial goal, declare "that" only as Pure intro (only for single
    78 steps); the "that" rule assumption may now be involved in implicit
    79 finishing, thus ".." becomes a feasible for trivial obtains;
    80 
    81 * Pure: default proof step now includes 'intro_classes'; thus trivial
    82 instance proofs may be performed by "..";
    83 
    84 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    85 statements as well;
    86 
    87 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    88 rule (as well as the assumption rule);
    89 
    90 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    91 lemmas, using the graph browser tool;
    92 
    93 * Pure: predict failure of "show" in interactive mode;
    94 
    95 * Pure: 'thms_containing' now takes actual terms as arguments;
    96 
    97 * HOL: improved method 'induct' --- now handles non-atomic goals
    98 (potential INCOMPATIBILITY); tuned error handling;
    99 
   100 * HOL: cases and induct rules now provide explicit hints about the
   101 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   102 any remaining facts are inserted into the goal verbatim;
   103 
   104 * HOL: local contexts (aka cases) may now contain term bindings as
   105 well; the 'cases' and 'induct' methods new provide a ?case binding for
   106 the result to be shown in each case;
   107 
   108 * HOL: added 'recdef_tc' command;
   109 
   110 * isatool convert assists in eliminating legacy ML scripts;
   111 
   112 
   113 *** HOL ***
   114 
   115 * HOL/Library: a collection of generic theories to be used together
   116 with main HOL; the theory loader path already includes this directory
   117 by default; the following existing theories have been moved here:
   118 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   119 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   120 
   121 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   122 modelling and verification task performed in Isabelle/HOL +
   123 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   124 
   125 * HOL basics: added overloaded operations "inverse" and "divide"
   126 (infix "/"), syntax for generic "abs" operation, generic summation
   127 operator;
   128 
   129 * HOL/typedef: simplified package, provide more useful rules (see also
   130 HOL/subset.thy);
   131 
   132 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   133 now expressed as a proper nested rule (old-style tactic scripts may
   134 require atomize_strip_tac to cope with non-atomic premises);
   135 
   136 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   137 to "split_conv" (old name still available for compatibility);
   138 
   139 * HOL: improved concrete syntax for strings (e.g. allows translation
   140 rules with string literals);
   141 
   142 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   143 and Fleuriot's mechanization of analysis;
   144 
   145 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   146 
   147 
   148 *** CTT ***
   149 
   150 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   151 "lam" is displayed as TWO lambda-symbols
   152 
   153 * CTT: theory Main now available, containing everything (that is, Bool
   154 and Arith);
   155 
   156 
   157 *** General ***
   158 
   159 * print modes "brackets" and "no_brackets" control output of nested =>
   160 (types) and ==> (props); the default behaviour is "brackets";
   161 
   162 * system: support Poly/ML 4.0 (current beta versions);
   163 
   164 * Pure: the Simplifier has been implemented properly as a derived rule
   165 outside of the actual kernel (at last!); the overall performance
   166 penalty in practical applications is about 50%, while reliability of
   167 the Isabelle inference kernel has been greatly improved;
   168 
   169 * Provers: fast_tac (and friends) now handle actual object-logic rules
   170 as assumptions as well;
   171 
   172 
   173 
   174 New in Isabelle99-1 (October 2000)
   175 ----------------------------------
   176 
   177 *** Overview of INCOMPATIBILITIES ***
   178 
   179 * HOL: simplification of natural numbers is much changed; to partly
   180 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   181 issue the following ML commands:
   182 
   183   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   184   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   185 
   186 * HOL: simplification no longer dives into case-expressions; this is
   187 controlled by "t.weak_case_cong" for each datatype t;
   188 
   189 * HOL: nat_less_induct renamed to less_induct;
   190 
   191 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   192 fixsome to patch .thy and .ML sources automatically;
   193 
   194   select_equality  -> some_equality
   195   select_eq_Ex     -> some_eq_ex
   196   selectI2EX       -> someI2_ex
   197   selectI2         -> someI2
   198   selectI          -> someI
   199   select1_equality -> some1_equality
   200   Eps_sym_eq       -> some_sym_eq_trivial
   201   Eps_eq           -> some_eq_trivial
   202 
   203 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   204 
   205 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   206 instead);
   207 
   208 * HOL: the recursion equations generated by 'recdef' are now called
   209 f.simps instead of f.rules;
   210 
   211 * HOL: qed_spec_mp now also handles bounded ALL as well;
   212 
   213 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   214 sometimes be needed;
   215 
   216 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   217 
   218 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   219 
   220 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   221 product is now "<*>" instead of "Times"; the lexicographic product is
   222 now "<*lex*>" instead of "**";
   223 
   224 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   225 of main HOL, but was unused); better use HOL's datatype package;
   226 
   227 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   228 the old syntax may be recovered as follows:
   229 
   230   syntax (symbols)
   231     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   232       (infixl "\\<oplus>" 100)
   233 
   234 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   235 
   236 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   237 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   238 internally;
   239 
   240 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   241 changed from A/r to A//r;
   242 
   243 * ZF: new treatment of arithmetic (nat & int) may break some old
   244 proofs;
   245 
   246 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   247 rulify -> rule_format, elimify -> elim_format, ...);
   248 
   249 * Isar/Provers: intro/elim/dest attributes changed; renamed
   250 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   251 should have to change intro!! to intro? only); replaced "delrule" by
   252 "rule del";
   253 
   254 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   255 
   256 * Provers: strengthened force_tac by using new first_best_tac;
   257 
   258 * LaTeX document preparation: several changes of isabelle.sty (see
   259 lib/texinputs);
   260 
   261 
   262 *** Document preparation ***
   263 
   264 * formal comments (text blocks etc.) in new-style theories may now
   265 contain antiquotations of thm/prop/term/typ/text to be presented
   266 according to latex print mode; concrete syntax is like this:
   267 @{term[show_types] "f(x) = a + x"};
   268 
   269 * isatool mkdir provides easy setup of Isabelle session directories,
   270 including proper document sources;
   271 
   272 * generated LaTeX sources are now deleted after successful run
   273 (isatool document -c); may retain a copy somewhere else via -D option
   274 of isatool usedir;
   275 
   276 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   277 style files, achieving self-contained LaTeX sources and simplifying
   278 LaTeX debugging;
   279 
   280 * old-style theories now produce (crude) LaTeX output as well;
   281 
   282 * browser info session directories are now self-contained (may be put
   283 on WWW server seperately); improved graphs of nested sessions; removed
   284 graph for 'all sessions';
   285 
   286 * several improvements in isabelle style files; \isabellestyle{it}
   287 produces fake math mode output; \isamarkupheader is now \section by
   288 default; see lib/texinputs/isabelle.sty etc.;
   289 
   290 
   291 *** Isar ***
   292 
   293 * Isar/Pure: local results and corresponding term bindings are now
   294 subject to Hindley-Milner polymorphism (similar to ML); this
   295 accommodates incremental type-inference very nicely;
   296 
   297 * Isar/Pure: new derived language element 'obtain' supports
   298 generalized existence reasoning;
   299 
   300 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   301 support accumulation of results, without applying any rules yet;
   302 useful to collect intermediate results without explicit name
   303 references, and for use with transitivity rules with more than 2
   304 premises;
   305 
   306 * Isar/Pure: scalable support for case-analysis type proofs: new
   307 'case' language element refers to local contexts symbolically, as
   308 produced by certain proof methods; internally, case names are attached
   309 to theorems as "tags";
   310 
   311 * Isar/Pure: theory command 'hide' removes declarations from
   312 class/type/const name spaces;
   313 
   314 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   315 indicate potential overloading;
   316 
   317 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   318 
   319 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   320 "{a,b,c}" instead of {a,b,c};
   321 
   322 * Isar/Pure now provides its own version of intro/elim/dest
   323 attributes; useful for building new logics, but beware of confusion
   324 with the version in Provers/classical;
   325 
   326 * Isar/Pure: the local context of (non-atomic) goals is provided via
   327 case name 'antecedent';
   328 
   329 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   330 to the current context is now done automatically);
   331 
   332 * Isar/Pure: theory command 'method_setup' provides a simple interface
   333 for definining proof methods in ML;
   334 
   335 * Isar/Provers: intro/elim/dest attributes changed; renamed
   336 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   337 most cases, one should have to change intro!! to intro? only);
   338 replaced "delrule" by "rule del";
   339 
   340 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   341 'symmetric' attribute (the latter supercedes [RS sym]);
   342 
   343 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   344 method modifier); 'simp' method: 'only:' modifier removes loopers as
   345 well (including splits);
   346 
   347 * Isar/Provers: Simplifier and Classical methods now support all kind
   348 of modifiers used in the past, including 'cong', 'iff', etc.
   349 
   350 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   351 of Simplifier and Classical reasoner);
   352 
   353 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   354 now support named cases; major packages (inductive, datatype, primrec,
   355 recdef) support case names and properly name parameters;
   356 
   357 * Isar/HOL: new transitivity rules for substitution in inequalities --
   358 monotonicity conditions are extracted to be proven at end of
   359 calculations;
   360 
   361 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   362 method anyway;
   363 
   364 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   365 split_if split_if_asm; datatype package provides theorems foo.splits =
   366 foo.split foo.split_asm for each datatype;
   367 
   368 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   369 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   370 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   371 use "(cases (simplified))" method in proper proof texts);
   372 
   373 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   374 
   375 * Isar: names of theorems etc. may be natural numbers as well;
   376 
   377 * Isar: 'pr' command: optional arguments for goals_limit and
   378 ProofContext.prems_limit; no longer prints theory contexts, but only
   379 proof states;
   380 
   381 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   382 additional print modes to be specified; e.g. "pr(latex)" will print
   383 proof state according to the Isabelle LaTeX style;
   384 
   385 * Isar: improved support for emulating tactic scripts, including proof
   386 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   387 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   388 (for HOL datatypes);
   389 
   390 * Isar: simplified (more robust) goal selection of proof methods: 1st
   391 goal, all goals, or explicit goal specifier (tactic emulation); thus
   392 'proof method scripts' have to be in depth-first order;
   393 
   394 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   395 
   396 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   397 should instead use individual commands for printing items
   398 (print_commands, print_methods etc.);
   399 
   400 * Isar: added 'nothing' --- the empty list of theorems;
   401 
   402 
   403 *** HOL ***
   404 
   405 * HOL/MicroJava: formalization of a fragment of Java, together with a
   406 corresponding virtual machine and a specification of its bytecode
   407 verifier and a lightweight bytecode verifier, including proofs of
   408 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   409 Cornelia Pusch (see also the homepage of project Bali at
   410 http://isabelle.in.tum.de/Bali/);
   411 
   412 * HOL/Algebra: new theory of rings and univariate polynomials, by
   413 Clemens Ballarin;
   414 
   415 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   416 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   417 Rasmussen;
   418 
   419 * HOL/Lattice: fundamental concepts of lattice theory and order
   420 structures, including duals, properties of bounds versus algebraic
   421 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   422 Theorem for complete lattices etc.; may also serve as a demonstration
   423 for abstract algebraic reasoning using axiomatic type classes, and
   424 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   425 
   426 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   427 von Oheimb;
   428 
   429 * HOL/IMPP: extension of IMP with local variables and mutually
   430 recursive procedures, by David von Oheimb;
   431 
   432 * HOL/Lambda: converted into new-style theory and document;
   433 
   434 * HOL/ex/Multiquote: example of multiple nested quotations and
   435 anti-quotations -- basically a generalized version of de-Bruijn
   436 representation; very useful in avoiding lifting of operations;
   437 
   438 * HOL/record: added general record equality rule to simpset; fixed
   439 select-update simplification procedure to handle extended records as
   440 well; admit "r" as field name;
   441 
   442 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   443 other numeric types and also as the identity of groups, rings, etc.;
   444 
   445 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   446 Types nat and int belong to this axclass;
   447 
   448 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   449    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   450    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   451   two terms #m*u and #n*u are replaced by #(m+n)*u
   452     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   453   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   454     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   455 
   456 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   457 powerful prover for predicate logic but knows nothing of clasets; see
   458 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   459 
   460 * HOL: new version of "case_tac" subsumes both boolean case split and
   461 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   462 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   463 
   464 * HOL: simplification no longer dives into case-expressions: only the
   465 selector expression is simplified, but not the remaining arms; to
   466 enable full simplification of case-expressions for datatype t, you may
   467 remove t.weak_case_cong from the simpset, either globally (Delcongs
   468 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   469 
   470 * HOL/recdef: the recursion equations generated by 'recdef' for
   471 function 'f' are now called f.simps instead of f.rules; if all
   472 termination conditions are proved automatically, these simplification
   473 rules are added to the simpset, as in primrec; rules may be named
   474 individually as well, resulting in a separate list of theorems for
   475 each equation;
   476 
   477 * HOL/While is a new theory that provides a while-combinator. It
   478 permits the definition of tail-recursive functions without the
   479 provision of a termination measure. The latter is necessary once the
   480 invariant proof rule for while is applied.
   481 
   482 * HOL: new (overloaded) notation for the set of elements below/above
   483 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   484 
   485 * HOL: theorems impI, allI, ballI bound as "strip";
   486 
   487 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   488 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   489 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   490 
   491 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   492 
   493 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   494 main HOL, but was unused);
   495 
   496 * HOL: fewer consts declared as global (e.g. have to refer to
   497 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   498 
   499 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   500 in case of overlap with user translations (e.g. judgements over
   501 tuples); (note that the underlying logical represenation is still
   502 bogus);
   503 
   504 
   505 *** ZF ***
   506 
   507 * ZF: simplification automatically cancels common terms in arithmetic
   508 expressions over nat and int;
   509 
   510 * ZF: new treatment of nat to minimize type-checking: all operators
   511 coerce their operands to a natural number using the function natify,
   512 making the algebraic laws unconditional;
   513 
   514 * ZF: as above, for int: operators coerce their operands to an integer
   515 using the function intify;
   516 
   517 * ZF: the integer library now contains many of the usual laws for the
   518 orderings, including $<=, and monotonicity laws for $+ and $*;
   519 
   520 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   521 simplification;
   522 
   523 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   524 to the simplifier and classical reasoner simultaneously;
   525 
   526 
   527 *** General ***
   528 
   529 * Provers: blast_tac now handles actual object-logic rules as
   530 assumptions; note that auto_tac uses blast_tac internally as well;
   531 
   532 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   533 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   534 
   535 * Provers: delrules now handles destruct rules as well (no longer need
   536 explicit make_elim);
   537 
   538 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   539   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   540 use instead the strong form,
   541   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   542 in HOL, FOL and ZF the function cla_make_elim will create such rules
   543 from destruct-rules;
   544 
   545 * Provers: Simplifier.easy_setup provides a fast path to basic
   546 Simplifier setup for new object-logics;
   547 
   548 * Pure: AST translation rules no longer require constant head on LHS;
   549 
   550 * Pure: improved name spaces: ambiguous output is qualified; support
   551 for hiding of names;
   552 
   553 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   554 XSYMBOL_HOME; no longer need to do manual configuration in most
   555 situations;
   556 
   557 * system: compression of ML heaps images may now be controlled via -c
   558 option of isabelle and isatool usedir (currently only observed by
   559 Poly/ML);
   560 
   561 * system: isatool installfonts may handle X-Symbol fonts as well (very
   562 useful for remote X11);
   563 
   564 * system: provide TAGS file for Isabelle sources;
   565 
   566 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   567 order;
   568 
   569 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   570 timing flag supersedes proof_timing and Toplevel.trace;
   571 
   572 * ML: new combinators |>> and |>>> for incremental transformations
   573 with secondary results (e.g. certain theory extensions):
   574 
   575 * ML: PureThy.add_defs gets additional argument to indicate potential
   576 overloading (usually false);
   577 
   578 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   579 results;
   580 
   581 
   582 
   583 New in Isabelle99 (October 1999)
   584 --------------------------------
   585 
   586 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   587 
   588 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   589 are no longer simplified.  (This allows the simplifier to unfold recursive
   590 functional programs.)  To restore the old behaviour, declare
   591 
   592     Delcongs [if_weak_cong];
   593 
   594 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   595 complement;
   596 
   597 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   598 
   599 * HOL/datatype: mutual_induct_tac no longer exists --
   600   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   601 
   602 * HOL/typedef: fixed type inference for representing set; type
   603 arguments now have to occur explicitly on the rhs as type constraints;
   604 
   605 * ZF: The con_defs part of an inductive definition may no longer refer
   606 to constants declared in the same theory;
   607 
   608 * HOL, ZF: the function mk_cases, generated by the inductive
   609 definition package, has lost an argument.  To simplify its result, it
   610 uses the default simpset instead of a supplied list of theorems.
   611 
   612 * HOL/List: the constructors of type list are now Nil and Cons;
   613 
   614 * Simplifier: the type of the infix ML functions
   615         setSSolver addSSolver setSolver addSolver
   616 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   617 for packaging solvers. A solver is created via
   618         mk_solver: string -> (thm list -> int -> tactic) -> solver
   619 where the string argument is only a comment.
   620 
   621 
   622 *** Proof tools ***
   623 
   624 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   625 decision procedure for linear arithmetic. Currently it is used for
   626 types `nat', `int', and `real' in HOL (see below); it can, should and
   627 will be instantiated for other types and logics as well.
   628 
   629 * The simplifier now accepts rewrite rules with flexible heads, eg
   630      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   631   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   632   matching.
   633 
   634 
   635 *** General ***
   636 
   637 * New Isabelle/Isar subsystem provides an alternative to traditional
   638 tactical theorem proving; together with the ProofGeneral/isar user
   639 interface it offers an interactive environment for developing human
   640 readable proof documents (Isar == Intelligible semi-automated
   641 reasoning); for further information see isatool doc isar-ref,
   642 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   643 
   644 * improved and simplified presentation of theories: better HTML markup
   645 (including colors), graph views in several sizes; isatool usedir now
   646 provides a proper interface for user theories (via -P option); actual
   647 document preparation based on (PDF)LaTeX is available as well (for
   648 new-style theories only); see isatool doc system for more information;
   649 
   650 * native support for Proof General, both for classic Isabelle and
   651 Isabelle/Isar;
   652 
   653 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   654 using the graph browser tool;
   655 
   656 * Isabelle manuals now also available as PDF;
   657 
   658 * theory loader rewritten from scratch (may not be fully
   659 bug-compatible); old loadpath variable has been replaced by show_path,
   660 add_path, del_path, reset_path functions; new operations such as
   661 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   662 isatool doc ref);
   663 
   664 * improved isatool install: option -k creates KDE application icon,
   665 option -p DIR installs standalone binaries;
   666 
   667 * added ML_PLATFORM setting (useful for cross-platform installations);
   668 more robust handling of platform specific ML images for SML/NJ;
   669 
   670 * the settings environment is now statically scoped, i.e. it is never
   671 created again in sub-processes invoked from isabelle, isatool, or
   672 Isabelle;
   673 
   674 * path element specification '~~' refers to '$ISABELLE_HOME';
   675 
   676 * in locales, the "assumes" and "defines" parts may be omitted if
   677 empty;
   678 
   679 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   680 long arrows);
   681 
   682 * new print_mode "HTML";
   683 
   684 * new flag show_tags controls display of tags of theorems (which are
   685 basically just comments that may be attached by some tools);
   686 
   687 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   688 mode and goal output format:
   689 
   690 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   691 244c244
   692 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   693 ---
   694 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   695 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   696 181c181
   697 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   698 ---
   699 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   700 
   701 * function bind_thms stores lists of theorems (cf. bind_thm);
   702 
   703 * new shorthand tactics ftac, eatac, datac, fatac;
   704 
   705 * qed (and friends) now accept "" as result name; in that case the
   706 theorem is not stored, but proper checks and presentation of the
   707 result still apply;
   708 
   709 * theorem database now also indexes constants "Trueprop", "all",
   710 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   711 
   712 
   713 *** HOL ***
   714 
   715 ** HOL arithmetic **
   716 
   717 * There are now decision procedures for linear arithmetic over nat and
   718 int:
   719 
   720 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   721 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   722 are treated as atomic; subformulae not involving type `nat' or `int'
   723 are ignored; quantified subformulae are ignored unless they are
   724 positive universal or negative existential. The tactic has to be
   725 invoked by hand and can be a little bit slow. In particular, the
   726 running time is exponential in the number of occurrences of `min' and
   727 `max', and `-' on `nat'.
   728 
   729 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   730 (negated) (in)equalities among the premises and the conclusion into
   731 account (i.e. no compound formulae) and does not know about `min' and
   732 `max', and `-' on `nat'. It is fast and is used automatically by the
   733 simplifier.
   734 
   735 NB: At the moment, these decision procedures do not cope with mixed
   736 nat/int formulae where the two parts interact, such as `m < n ==>
   737 int(m) < int(n)'.
   738 
   739 * HOL/Numeral provides a generic theory of numerals (encoded
   740 efficiently as bit strings); setup for types nat/int/real is in place;
   741 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   742 int, existing theories and proof scripts may require a few additional
   743 type constraints;
   744 
   745 * integer division and remainder can now be performed on constant
   746 arguments;
   747 
   748 * many properties of integer multiplication, division and remainder
   749 are now available;
   750 
   751 * An interface to the Stanford Validity Checker (SVC) is available through the
   752 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   753 are proved automatically.  SVC must be installed separately, and its results
   754 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   755 invocation of the underlying oracle).  For SVC see
   756   http://verify.stanford.edu/SVC
   757 
   758 * IsaMakefile: the HOL-Real target now builds an actual image;
   759 
   760 
   761 ** HOL misc **
   762 
   763 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   764 (in Isabelle/Isar) -- by Gertrud Bauer;
   765 
   766 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   767 analysis for assembly languages with subtypes;
   768 
   769 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   770 -- avoids syntactic ambiguities and treats state, transition, and
   771 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   772 changed syntax and (many) tactics;
   773 
   774 * HOL/inductive: Now also handles more general introduction rules such
   775   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   776   theorems are now maintained within the theory (maintained via the
   777   "mono" attribute);
   778 
   779 * HOL/datatype: Now also handles arbitrarily branching datatypes
   780   (using function types) such as
   781 
   782   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   783 
   784 * HOL/record: record_simproc (part of the default simpset) takes care
   785 of selectors applied to updated records; record_split_tac is no longer
   786 part of the default claset; update_defs may now be removed from the
   787 simpset in many cases; COMPATIBILITY: old behavior achieved by
   788 
   789   claset_ref () := claset() addSWrapper record_split_wrapper;
   790   Delsimprocs [record_simproc]
   791 
   792 * HOL/typedef: fixed type inference for representing set; type
   793 arguments now have to occur explicitly on the rhs as type constraints;
   794 
   795 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   796 names rather than an ML expression;
   797 
   798 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   799 supplied later.  Program schemes can be defined, such as
   800     "While B C s = (if B s then While B C (C s) else s)"
   801 where the well-founded relation can be chosen after B and C have been given.
   802 
   803 * HOL/List: the constructors of type list are now Nil and Cons;
   804 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   805 course, ML tools referring to List.list.op # etc. have to be adapted;
   806 
   807 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   808 disabled by default; run isabelle with option -m HOL to get back to
   809 the original Gordon/HOL-style output;
   810 
   811 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   812 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   813 
   814 * HOL basic syntax simplified (more orthogonal): all variants of
   815 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   816 Eps operator is provided as well: "SOME x. P[x]";
   817 
   818 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   819 
   820 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   821 thus available for user theories;
   822 
   823 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   824 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   825 time;
   826 
   827 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   828 several times and then mp;
   829 
   830 
   831 *** LK ***
   832 
   833 * the notation <<...>> is now available as a notation for sequences of
   834 formulas;
   835 
   836 * the simplifier is now installed
   837 
   838 * the axiom system has been generalized (thanks to Soren Heilmann)
   839 
   840 * the classical reasoner now has a default rule database
   841 
   842 
   843 *** ZF ***
   844 
   845 * new primrec section allows primitive recursive functions to be given
   846 directly (as in HOL) over datatypes and the natural numbers;
   847 
   848 * new tactics induct_tac and exhaust_tac for induction (or case
   849 analysis) over datatypes and the natural numbers;
   850 
   851 * the datatype declaration of type T now defines the recursor T_rec;
   852 
   853 * simplification automatically does freeness reasoning for datatype
   854 constructors;
   855 
   856 * automatic type-inference, with AddTCs command to insert new
   857 type-checking rules;
   858 
   859 * datatype introduction rules are now added as Safe Introduction rules
   860 to the claset;
   861 
   862 * the syntax "if P then x else y" is now available in addition to
   863 if(P,x,y);
   864 
   865 
   866 *** Internal programming interfaces ***
   867 
   868 * tuned simplifier trace output; new flag debug_simp;
   869 
   870 * structures Vartab / Termtab (instances of TableFun) offer efficient
   871 tables indexed by indexname_ord / term_ord (compatible with aconv);
   872 
   873 * AxClass.axclass_tac lost the theory argument;
   874 
   875 * tuned current_goals_markers semantics: begin / end goal avoids
   876 printing empty lines;
   877 
   878 * removed prs and prs_fn hook, which was broken because it did not
   879 include \n in its semantics, forcing writeln to add one
   880 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   881 string -> unit if you really want to output text without newline;
   882 
   883 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   884 plain output, interface builders may have to enable 'isabelle_font'
   885 mode to get Isabelle font glyphs as before;
   886 
   887 * refined token_translation interface; INCOMPATIBILITY: output length
   888 now of type real instead of int;
   889 
   890 * theory loader actions may be traced via new ThyInfo.add_hook
   891 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   892 your own database of information attached to *whole* theories -- as
   893 opposed to intra-theory data slots offered via TheoryDataFun;
   894 
   895 * proper handling of dangling sort hypotheses (at last!);
   896 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   897 extra sort hypotheses that can be witnessed from the type signature;
   898 the force_strip_shyps flag is gone, any remaining shyps are simply
   899 left in the theorem (with a warning issued by strip_shyps_warning);
   900 
   901 
   902 
   903 New in Isabelle98-1 (October 1998)
   904 ----------------------------------
   905 
   906 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   907 
   908 * several changes of automated proof tools;
   909 
   910 * HOL: major changes to the inductive and datatype packages, including
   911 some minor incompatibilities of theory syntax;
   912 
   913 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   914 called `inj_on';
   915 
   916 * HOL: removed duplicate thms in Arith:
   917   less_imp_add_less  should be replaced by  trans_less_add1
   918   le_imp_add_le      should be replaced by  trans_le_add1
   919 
   920 * HOL: unary minus is now overloaded (new type constraints may be
   921 required);
   922 
   923 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   924 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   925 now taken as an integer constant.
   926 
   927 * Pure: ML function 'theory_of' renamed to 'theory';
   928 
   929 
   930 *** Proof tools ***
   931 
   932 * Simplifier:
   933   1. Asm_full_simp_tac is now more aggressive.
   934      1. It will sometimes reorient premises if that increases their power to
   935         simplify.
   936      2. It does no longer proceed strictly from left to right but may also
   937         rotate premises to achieve further simplification.
   938      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   939      old Asm_full_simp_tac in that it does not rotate premises.
   940   2. The simplifier now knows a little bit about nat-arithmetic.
   941 
   942 * Classical reasoner: wrapper mechanism for the classical reasoner now
   943 allows for selected deletion of wrappers, by introduction of names for
   944 wrapper functionals.  This implies that addbefore, addSbefore,
   945 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   946 and that adding two tactics with the same name overwrites the first
   947 one (emitting a warning).
   948   type wrapper = (int -> tactic) -> (int -> tactic)
   949   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   950   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   951   delWrapper, delSWrapper: claset *  string            -> claset
   952   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   953 
   954 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   955 semantics; addbefore now affects only the unsafe part of step_tac
   956 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   957 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   958 by Force_tac;
   959 
   960 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   961 compWrapper; added safe wrapper (and access functions for it);
   962 
   963 * HOL/split_all_tac is now much faster and fails if there is nothing
   964 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   965 and the names of the automatically generated variables have changed.
   966 split_all_tac has moved within claset() from unsafe wrappers to safe
   967 wrappers, which means that !!-bound variables are split much more
   968 aggressively, and safe_tac and clarify_tac now split such variables.
   969 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   970 Note: the same holds for record_split_tac, which does the job of
   971 split_all_tac for record fields.
   972 
   973 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   974 permanently to the default simpset using Addsplits just like
   975 Addsimps. They can be removed via Delsplits just like
   976 Delsimps. Lower-case versions are also available.
   977 
   978 * HOL/Simplifier: The rule split_if is now part of the default
   979 simpset. This means that the simplifier will eliminate all occurrences
   980 of if-then-else in the conclusion of a goal. To prevent this, you can
   981 either remove split_if completely from the default simpset by
   982 `Delsplits [split_if]' or remove it in a specific call of the
   983 simplifier using `... delsplits [split_if]'.  You can also add/delete
   984 other case splitting rules to/from the default simpset: every datatype
   985 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   986 t is the name of the datatype).
   987 
   988 * Classical reasoner / Simplifier combination: new force_tac (and
   989 derivatives Force_tac, force) combines rewriting and classical
   990 reasoning (and whatever other tools) similarly to auto_tac, but is
   991 aimed to solve the given subgoal completely.
   992 
   993 
   994 *** General ***
   995 
   996 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   997 and `goalw': the theory is no longer needed as an explicit argument -
   998 the current theory context is used; assumptions are no longer returned
   999 at the ML-level unless one of them starts with ==> or !!; it is
  1000 recommended to convert to these new commands using isatool fixgoal
  1001 (backup your sources first!);
  1002 
  1003 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1004 the current theory context, and 'theory' to lookup stored theories;
  1005 
  1006 * new theory section 'locale' for declaring constants, assumptions and
  1007 definitions that have local scope;
  1008 
  1009 * new theory section 'nonterminals' for purely syntactic types;
  1010 
  1011 * new theory section 'setup' for generic ML setup functions
  1012 (e.g. package initialization);
  1013 
  1014 * the distribution now includes Isabelle icons: see
  1015 lib/logo/isabelle-{small,tiny}.xpm;
  1016 
  1017 * isatool install - install binaries with absolute references to
  1018 ISABELLE_HOME/bin;
  1019 
  1020 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1021 
  1022 * print mode 'emacs' reserved for Isamode;
  1023 
  1024 * support multiple print (ast) translations per constant name;
  1025 
  1026 * theorems involving oracles are now printed with a suffixed [!];
  1027 
  1028 
  1029 *** HOL ***
  1030 
  1031 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1032 
  1033 * HOL/inductive package reorganized and improved: now supports mutual
  1034 definitions such as
  1035 
  1036   inductive EVEN ODD
  1037     intrs
  1038       null "0 : EVEN"
  1039       oddI "n : EVEN ==> Suc n : ODD"
  1040       evenI "n : ODD ==> Suc n : EVEN"
  1041 
  1042 new theorem list "elims" contains an elimination rule for each of the
  1043 recursive sets; inductive definitions now handle disjunctive premises
  1044 correctly (also ZF);
  1045 
  1046 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1047 "mutual_induct" no longer exists - the induction rule is always
  1048 contained in "induct";
  1049 
  1050 
  1051 * HOL/datatype package re-implemented and greatly improved: now
  1052 supports mutually recursive datatypes such as
  1053 
  1054   datatype
  1055     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1056             | SUM ('a aexp) ('a aexp)
  1057             | DIFF ('a aexp) ('a aexp)
  1058             | NUM 'a
  1059   and
  1060     'a bexp = LESS ('a aexp) ('a aexp)
  1061             | AND ('a bexp) ('a bexp)
  1062             | OR ('a bexp) ('a bexp)
  1063 
  1064 as well as indirectly recursive datatypes such as
  1065 
  1066   datatype
  1067     ('a, 'b) term = Var 'a
  1068                   | App 'b ((('a, 'b) term) list)
  1069 
  1070 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1071 induction on mutually / indirectly recursive datatypes.
  1072 
  1073 Primrec equations are now stored in theory and can be accessed via
  1074 <function_name>.simps.
  1075 
  1076 INCOMPATIBILITIES:
  1077 
  1078   - Theories using datatypes must now have theory Datatype as an
  1079     ancestor.
  1080   - The specific <typename>.induct_tac no longer exists - use the
  1081     generic induct_tac instead.
  1082   - natE has been renamed to nat.exhaust - use exhaust_tac
  1083     instead of res_inst_tac ... natE. Note that the variable
  1084     names in nat.exhaust differ from the names in natE, this
  1085     may cause some "fragile" proofs to fail.
  1086   - The theorems split_<typename>_case and split_<typename>_case_asm
  1087     have been renamed to <typename>.split and <typename>.split_asm.
  1088   - Since default sorts of type variables are now handled correctly,
  1089     some datatype definitions may have to be annotated with explicit
  1090     sort constraints.
  1091   - Primrec definitions no longer require function name and type
  1092     of recursive argument.
  1093 
  1094 Consider using isatool fixdatatype to adapt your theories and proof
  1095 scripts to the new package (backup your sources first!).
  1096 
  1097 
  1098 * HOL/record package: considerably improved implementation; now
  1099 includes concrete syntax for record types, terms, updates; theorems
  1100 for surjective pairing and splitting !!-bound record variables; proof
  1101 support is as follows:
  1102 
  1103   1) standard conversions (selectors or updates applied to record
  1104 constructor terms) are part of the standard simpset;
  1105 
  1106   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1107 made part of standard simpset and claset via addIffs;
  1108 
  1109   3) a tactic for record field splitting (record_split_tac) is part of
  1110 the standard claset (addSWrapper);
  1111 
  1112 To get a better idea about these rules you may retrieve them via
  1113 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1114 the name of your record type.
  1115 
  1116 The split tactic 3) conceptually simplifies by the following rule:
  1117 
  1118   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1119 
  1120 Thus any record variable that is bound by meta-all will automatically
  1121 blow up into some record constructor term, consequently the
  1122 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1123 solve record problems automatically.
  1124 
  1125 
  1126 * reorganized the main HOL image: HOL/Integ and String loaded by
  1127 default; theory Main includes everything;
  1128 
  1129 * automatic simplification of integer sums and comparisons, using cancellation;
  1130 
  1131 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1132 
  1133 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1134 
  1135 * many new identities for unions, intersections, set difference, etc.;
  1136 
  1137 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1138 called split_if, split_split, split_sum_case and split_nat_case (to go
  1139 with add/delsplits);
  1140 
  1141 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1142 (?x::unit) = (); this is made part of the default simpset, which COULD
  1143 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1144 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1145 unit_abs_eta_conv is added in order to counter the effect of
  1146 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1147 %u.f();
  1148 
  1149 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1150 makes more sense);
  1151 
  1152 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1153   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1154   disjointness reasoning but breaking a few old proofs.
  1155 
  1156 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1157 to 'converse' from 'inverse' (for compatibility with ZF and some
  1158 literature);
  1159 
  1160 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1161 the well-founded relation;
  1162 
  1163 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1164     Compl A.  The "Compl" syntax remains available as input syntax for this
  1165     release ONLY.
  1166 
  1167 * HOL/Update: new theory of function updates:
  1168     f(a:=b) == %x. if x=a then b else f x
  1169 may also be iterated as in f(a:=b,c:=d,...);
  1170 
  1171 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1172 
  1173 * HOL/List:
  1174   - new function list_update written xs[i:=v] that updates the i-th
  1175     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1176   - new function `upt' written [i..j(] which generates the list
  1177     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1178     bound write [i..j], which is a shorthand for [i..j+1(].
  1179   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1180 
  1181 * HOL/Arith:
  1182   - removed 'pred' (predecessor) function;
  1183   - generalized some theorems about n-1;
  1184   - many new laws about "div" and "mod";
  1185   - new laws about greatest common divisors (see theory ex/Primes);
  1186 
  1187 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1188 instead of "inverse";
  1189 
  1190 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1191   of the multiset ordering;
  1192 
  1193 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1194   (not included by default);
  1195 
  1196 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1197 
  1198 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1199   programs, i.e. different program variables may have different types.
  1200 
  1201 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1202   [previously, this check worked only if the rewrite rule was unconditional]
  1203   Now rew can involve either definitions or equalities (either == or =).
  1204 
  1205 
  1206 *** ZF ***
  1207 
  1208 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1209   only the theorems proved on ZF.ML;
  1210 
  1211 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1212   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1213   disjointness reasoning but breaking a few old proofs.
  1214 
  1215 * ZF/Update: new theory of function updates
  1216     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1217   may also be iterated as in f(a:=b,c:=d,...);
  1218 
  1219 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1220 
  1221 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1222   [previously, this check worked only if the rewrite rule was unconditional]
  1223   Now rew can involve either definitions or equalities (either == or =).
  1224 
  1225 * case_tac provided for compatibility with HOL
  1226     (like the old excluded_middle_tac, but with subgoals swapped)
  1227 
  1228 
  1229 *** Internal programming interfaces ***
  1230 
  1231 * Pure: several new basic modules made available for general use, see
  1232 also src/Pure/README;
  1233 
  1234 * improved the theory data mechanism to support encapsulation (data
  1235 kind name replaced by private Object.kind, acting as authorization
  1236 key); new type-safe user interface via functor TheoryDataFun; generic
  1237 print_data function becomes basically useless;
  1238 
  1239 * removed global_names compatibility flag -- all theory declarations
  1240 are qualified by default;
  1241 
  1242 * module Pure/Syntax now offers quote / antiquote translation
  1243 functions (useful for Hoare logic etc. with implicit dependencies);
  1244 see HOL/ex/Antiquote for an example use;
  1245 
  1246 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1247 cterm -> thm;
  1248 
  1249 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1250 subgoal;
  1251 
  1252 * Display.print_goals function moved to Locale.print_goals;
  1253 
  1254 * standard print function for goals supports current_goals_markers
  1255 variable for marking begin of proof, end of proof, start of goal; the
  1256 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1257 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1258 for example;
  1259 
  1260 
  1261 
  1262 New in Isabelle98 (January 1998)
  1263 --------------------------------
  1264 
  1265 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1266 
  1267 * changed lexical syntax of terms / types: dots made part of long
  1268 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1269 
  1270 * simpset (and claset) reference variable replaced by functions
  1271 simpset / simpset_ref;
  1272 
  1273 * no longer supports theory aliases (via merge) and non-trivial
  1274 implicit merge of thms' signatures;
  1275 
  1276 * most internal names of constants changed due to qualified names;
  1277 
  1278 * changed Pure/Sequence interface (see Pure/seq.ML);
  1279 
  1280 
  1281 *** General Changes ***
  1282 
  1283 * hierachically structured name spaces (for consts, types, axms, thms
  1284 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1285 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1286 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1287 long_names for fully qualified output names; NOTE: ML programs
  1288 (special tactics, packages etc.) referring to internal names may have
  1289 to be adapted to cope with fully qualified names; in case of severe
  1290 backward campatibility problems try setting 'global_names' at compile
  1291 time to have enrything declared within a flat name space; one may also
  1292 fine tune name declarations in theories via the 'global' and 'local'
  1293 section;
  1294 
  1295 * reimplemented the implicit simpset and claset using the new anytype
  1296 data filed in signatures; references simpset:simpset ref etc. are
  1297 replaced by functions simpset:unit->simpset and
  1298 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1299 to patch your ML files accordingly;
  1300 
  1301 * HTML output now includes theory graph data for display with Java
  1302 applet or isatool browser; data generated automatically via isatool
  1303 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1304 
  1305 * defs may now be conditional; improved rewrite_goals_tac to handle
  1306 conditional equations;
  1307 
  1308 * defs now admits additional type arguments, using TYPE('a) syntax;
  1309 
  1310 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1311 creates a new theory node; implicit merge of thms' signatures is
  1312 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1313 transfer:theory->thm->thm in (rare) cases;
  1314 
  1315 * improved handling of draft signatures / theories; draft thms (and
  1316 ctyps, cterms) are automatically promoted to real ones;
  1317 
  1318 * slightly changed interfaces for oracles: admit many per theory, named
  1319 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1320 
  1321 * print_goals: optional output of const types (set show_consts and
  1322 show_types);
  1323 
  1324 * improved output of warnings (###) and errors (***);
  1325 
  1326 * subgoal_tac displays a warning if the new subgoal has type variables;
  1327 
  1328 * removed old README and Makefiles;
  1329 
  1330 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1331 
  1332 * removed obsolete init_pps and init_database;
  1333 
  1334 * deleted the obsolete tactical STATE, which was declared by
  1335     fun STATE tacfun st = tacfun st st;
  1336 
  1337 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1338 (which abbreviates $HOME);
  1339 
  1340 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1341 use isatool fixseq to adapt your ML programs (this works for fully
  1342 qualified references to the Sequence structure only!);
  1343 
  1344 * use_thy no longer requires writable current directory; it always
  1345 reloads .ML *and* .thy file, if either one is out of date;
  1346 
  1347 
  1348 *** Classical Reasoner ***
  1349 
  1350 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1351 tactics that use classical reasoning to simplify a subgoal without
  1352 splitting it into several subgoals;
  1353 
  1354 * Safe_tac: like safe_tac but uses the default claset;
  1355 
  1356 
  1357 *** Simplifier ***
  1358 
  1359 * added simplification meta rules:
  1360     (asm_)(full_)simplify: simpset -> thm -> thm;
  1361 
  1362 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1363 logics (again);
  1364 
  1365 * added prems argument to simplification procedures;
  1366 
  1367 * HOL, FOL, ZF: added infix function `addsplits':
  1368   instead of `<simpset> setloop (split_tac <thms>)'
  1369   you can simply write `<simpset> addsplits <thms>'
  1370 
  1371 
  1372 *** Syntax ***
  1373 
  1374 * TYPE('a) syntax for type reflection terms;
  1375 
  1376 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1377 
  1378 * pretty printer: changed order of mixfix annotation preference (again!);
  1379 
  1380 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1381 
  1382 
  1383 *** HOL ***
  1384 
  1385 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1386   with `addloop' of the simplifier to faciliate case splitting in premises.
  1387 
  1388 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1389 
  1390 * HOL/Auth: new protocol proofs including some for the Internet
  1391   protocol TLS;
  1392 
  1393 * HOL/Map: new theory of `maps' a la VDM;
  1394 
  1395 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1396 cancelling out common nat summands from =, <, <= (in)equalities, or
  1397 differences; simplification procedures nat_cancel_factor for
  1398 cancelling common factor from =, <, <= (in)equalities over natural
  1399 sums; nat_cancel contains both kinds of procedures, it is installed by
  1400 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1401 
  1402 * HOL/simplifier: terms of the form
  1403   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1404   are rewritten to
  1405   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1406   and those of the form
  1407   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1408   are rewritten to
  1409   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1410 
  1411 * HOL/datatype
  1412   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1413 
  1414   P(t_case f1 ... fn x) =
  1415      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1416         ...
  1417        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1418      )
  1419 
  1420   and a theorem `split_t_case_asm' of the form
  1421 
  1422   P(t_case f1 ... fn x) =
  1423     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1424         ...
  1425        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1426      )
  1427   which can be added to a simpset via `addsplits'. The existing theorems
  1428   expand_list_case and expand_option_case have been renamed to
  1429   split_list_case and split_option_case.
  1430 
  1431 * HOL/Arithmetic:
  1432   - `pred n' is automatically converted to `n-1'.
  1433     Users are strongly encouraged not to use `pred' any longer,
  1434     because it will disappear altogether at some point.
  1435   - Users are strongly encouraged to write "0 < n" rather than
  1436     "n ~= 0". Theorems and proof tools have been modified towards this
  1437     `standard'.
  1438 
  1439 * HOL/Lists:
  1440   the function "set_of_list" has been renamed "set" (and its theorems too);
  1441   the function "nth" now takes its arguments in the reverse order and
  1442   has acquired the infix notation "!" as in "xs!n".
  1443 
  1444 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1445 
  1446 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1447   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1448 
  1449 * HOL/record: extensible records with schematic structural subtyping
  1450 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1451 still lacks various theorems and concrete record syntax;
  1452 
  1453 
  1454 *** HOLCF ***
  1455 
  1456 * removed "axioms" and "generated by" sections;
  1457 
  1458 * replaced "ops" section by extended "consts" section, which is capable of
  1459   handling the continuous function space "->" directly;
  1460 
  1461 * domain package:
  1462   . proves theorems immediately and stores them in the theory,
  1463   . creates hierachical name space,
  1464   . now uses normal mixfix annotations (instead of cinfix...),
  1465   . minor changes to some names and values (for consistency),
  1466   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1467   . separator between mutual domain defs: changed "," to "and",
  1468   . improved handling of sort constraints;  now they have to
  1469     appear on the left-hand side of the equations only;
  1470 
  1471 * fixed LAM <x,y,zs>.b syntax;
  1472 
  1473 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1474 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1475 
  1476 
  1477 *** FOL and ZF ***
  1478 
  1479 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1480   with `addloop' of the simplifier to faciliate case splitting in premises.
  1481 
  1482 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1483 in HOL, they strip ALL and --> from proved theorems;
  1484 
  1485 
  1486 
  1487 New in Isabelle94-8 (May 1997)
  1488 ------------------------------
  1489 
  1490 *** General Changes ***
  1491 
  1492 * new utilities to build / run / maintain Isabelle etc. (in parts
  1493 still somewhat experimental); old Makefiles etc. still functional;
  1494 
  1495 * new 'Isabelle System Manual';
  1496 
  1497 * INSTALL text, together with ./configure and ./build scripts;
  1498 
  1499 * reimplemented type inference for greater efficiency, better error
  1500 messages and clean internal interface;
  1501 
  1502 * prlim command for dealing with lots of subgoals (an easier way of
  1503 setting goals_limit);
  1504 
  1505 
  1506 *** Syntax ***
  1507 
  1508 * supports alternative (named) syntax tables (parser and pretty
  1509 printer); internal interface is provided by add_modesyntax(_i);
  1510 
  1511 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1512 be used in conjunction with the Isabelle symbol font; uses the
  1513 "symbols" syntax table;
  1514 
  1515 * added token_translation interface (may translate name tokens in
  1516 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1517 the current print_mode); IMPORTANT: user print translation functions
  1518 are responsible for marking newly introduced bounds
  1519 (Syntax.mark_boundT);
  1520 
  1521 * token translations for modes "xterm" and "xterm_color" that display
  1522 names in bold, underline etc. or colors (which requires a color
  1523 version of xterm);
  1524 
  1525 * infixes may now be declared with names independent of their syntax;
  1526 
  1527 * added typed_print_translation (like print_translation, but may
  1528 access type of constant);
  1529 
  1530 
  1531 *** Classical Reasoner ***
  1532 
  1533 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1534 some limitations.  Blast_tac...
  1535   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1536   + ignores elimination rules that don't have the correct format
  1537         (the conclusion MUST be a formula variable)
  1538   + ignores types, which can make HOL proofs fail
  1539   + rules must not require higher-order unification, e.g. apply_type in ZF
  1540     [message "Function Var's argument not a bound variable" relates to this]
  1541   + its proof strategy is more general but can actually be slower
  1542 
  1543 * substitution with equality assumptions no longer permutes other
  1544 assumptions;
  1545 
  1546 * minor changes in semantics of addafter (now called addaltern); renamed
  1547 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1548 (and access functions for it);
  1549 
  1550 * improved combination of classical reasoner and simplifier:
  1551   + functions for handling clasimpsets
  1552   + improvement of addss: now the simplifier is called _after_ the
  1553     safe steps.
  1554   + safe variant of addss called addSss: uses safe simplifications
  1555     _during_ the safe steps. It is more complete as it allows multiple
  1556     instantiations of unknowns (e.g. with slow_tac).
  1557 
  1558 *** Simplifier ***
  1559 
  1560 * added interface for simplification procedures (functions that
  1561 produce *proven* rewrite rules on the fly, depending on current
  1562 redex);
  1563 
  1564 * ordering on terms as parameter (used for ordered rewriting);
  1565 
  1566 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1567 
  1568 * the solver is now split into a safe and an unsafe part.
  1569 This should be invisible for the normal user, except that the
  1570 functions setsolver and addsolver have been renamed to setSolver and
  1571 addSolver; added safe_asm_full_simp_tac;
  1572 
  1573 
  1574 *** HOL ***
  1575 
  1576 * a generic induction tactic `induct_tac' which works for all datatypes and
  1577 also for type `nat';
  1578 
  1579 * a generic case distinction tactic `exhaust_tac' which works for all
  1580 datatypes and also for type `nat';
  1581 
  1582 * each datatype comes with a function `size';
  1583 
  1584 * patterns in case expressions allow tuple patterns as arguments to
  1585 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1586 
  1587 * primrec now also works with type nat;
  1588 
  1589 * recdef: a new declaration form, allows general recursive functions to be
  1590 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1591 
  1592 * the constant for negation has been renamed from "not" to "Not" to
  1593 harmonize with FOL, ZF, LK, etc.;
  1594 
  1595 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1596 infinite lists;
  1597 
  1598 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1599 
  1600 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1601 problems in commutative rings, using axiomatic type classes for + and *;
  1602 
  1603 * more examples in HOL/MiniML and HOL/Auth;
  1604 
  1605 * more default rewrite rules for quantifiers, union/intersection;
  1606 
  1607 * a new constant `arbitrary == @x.False';
  1608 
  1609 * HOLCF/IOA replaces old HOL/IOA;
  1610 
  1611 * HOLCF changes: derived all rules and arities
  1612   + axiomatic type classes instead of classes
  1613   + typedef instead of faking type definitions
  1614   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1615   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1616   + eliminated the types void, one, tr
  1617   + use unit lift and bool lift (with translations) instead of one and tr
  1618   + eliminated blift from Lift3.thy (use Def instead of blift)
  1619   all eliminated rules are derived as theorems --> no visible changes ;
  1620 
  1621 
  1622 *** ZF ***
  1623 
  1624 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1625 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1626 as ZF_cs addSIs [equalityI];
  1627 
  1628 
  1629 
  1630 New in Isabelle94-7 (November 96)
  1631 ---------------------------------
  1632 
  1633 * allowing negative levels (as offsets) in prlev and choplev;
  1634 
  1635 * super-linear speedup for large simplifications;
  1636 
  1637 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1638 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1639 FAIL); can suppress it using the command Delsimps (ex_simps @
  1640 all_simps); De Morgan laws are also now included, by default;
  1641 
  1642 * improved printing of ==>  :  ~:
  1643 
  1644 * new object-logic "Sequents" adds linear logic, while replacing LK
  1645 and Modal (thanks to Sara Kalvala);
  1646 
  1647 * HOL/Auth: correctness proofs for authentication protocols;
  1648 
  1649 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1650 examples on HOL/Auth);
  1651 
  1652 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1653 the rewriter and classical reasoner simultaneously;
  1654 
  1655 * function uresult no longer returns theorems in "standard" format;
  1656 regain previous version by: val uresult = standard o uresult;
  1657 
  1658 
  1659 
  1660 New in Isabelle94-6
  1661 -------------------
  1662 
  1663 * oracles -- these establish an interface between Isabelle and trusted
  1664 external reasoners, which may deliver results as theorems;
  1665 
  1666 * proof objects (in particular record all uses of oracles);
  1667 
  1668 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1669 
  1670 * "constdefs" section in theory files;
  1671 
  1672 * "primrec" section (HOL) no longer requires names;
  1673 
  1674 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1675 
  1676 
  1677 
  1678 New in Isabelle94-5
  1679 -------------------
  1680 
  1681 * reduced space requirements;
  1682 
  1683 * automatic HTML generation from theories;
  1684 
  1685 * theory files no longer require "..." (quotes) around most types;
  1686 
  1687 * new examples, including two proofs of the Church-Rosser theorem;
  1688 
  1689 * non-curried (1994) version of HOL is no longer distributed;
  1690 
  1691 
  1692 
  1693 New in Isabelle94-4
  1694 -------------------
  1695 
  1696 * greatly reduced space requirements;
  1697 
  1698 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1699 
  1700 * searchable theorem database (see the section "Retrieving theorems" on
  1701 page 8 of the Reference Manual);
  1702 
  1703 * new examples, including Grabczewski's monumental case study of the
  1704 Axiom of Choice;
  1705 
  1706 * The previous version of HOL renamed to Old_HOL;
  1707 
  1708 * The new version of HOL (previously called CHOL) uses a curried syntax
  1709 for functions.  Application looks like f a b instead of f(a,b);
  1710 
  1711 * Mutually recursive inductive definitions finally work in HOL;
  1712 
  1713 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1714 translates to the operator "split";
  1715 
  1716 
  1717 
  1718 New in Isabelle94-3
  1719 -------------------
  1720 
  1721 * new infix operator, addss, allowing the classical reasoner to
  1722 perform simplification at each step of its search.  Example:
  1723         fast_tac (cs addss ss)
  1724 
  1725 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1726 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1727 look like (a,b) instead of <a,b>;
  1728 
  1729 * PLEASE NOTE: CHOL will eventually replace HOL!
  1730 
  1731 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1732 It translates to the operator "split".  A new theory of integers is available;
  1733 
  1734 * In ZF, integer numerals now denote two's-complement binary integers.
  1735 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1736 
  1737 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1738 of the Axiom of Choice;
  1739 
  1740 
  1741 
  1742 New in Isabelle94-2
  1743 -------------------
  1744 
  1745 * Significantly faster resolution;
  1746 
  1747 * the different sections in a .thy file can now be mixed and repeated
  1748 freely;
  1749 
  1750 * Database of theorems for FOL, HOL and ZF.  New
  1751 commands including qed, qed_goal and bind_thm store theorems in the database.
  1752 
  1753 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1754 a given theory (thms_of), or find out what theory a theorem was proved in
  1755 (theory_of_thm);
  1756 
  1757 * Bugs fixed in the inductive definition and datatype packages;
  1758 
  1759 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1760 and HOL_dup_cs obsolete;
  1761 
  1762 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1763 have been removed;
  1764 
  1765 * Simpler definition of function space in ZF;
  1766 
  1767 * new results about cardinal and ordinal arithmetic in ZF;
  1768 
  1769 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1770 types;
  1771 
  1772 
  1773 $Id$