NEWS
author nipkow
Thu Jan 11 12:49:48 2001 +0100 (2001-01-11)
changeset 10868 5af3906edec8
parent 10862 857688d775b0
child 10915 6b66a8a530ce
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 *** Overview of INCOMPATIBILITIES ***
     5 
     6 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
     7 operation;
     8 
     9 * HOL: induct renamed to lfp_induct;
    10 
    11 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    12 
    13 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    14 relation); infix "^^" has been renamed "``"; infix "``" has been
    15 renamed "`"; "univalent" has been renamed "single_valued";
    16 
    17 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    18 
    19 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    20 
    21 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    22 consequence, it is no longer monotonic wrt. the local goal context
    23 (which is now passed through the inductive cases);
    24 
    25 
    26 *** Document preparation ***
    27 
    28 * improved isabelle style files; more abstract symbol implementation
    29 (should now use \isamath{...} and \isatext{...} in custom symbol
    30 definitions);
    31 
    32 * \isabellestyle{NAME} selects version of Isabelle output (currently
    33 available: are "it" for near math-mode best-style output, "sl" for
    34 slanted text style, and "tt" for plain type-writer; if no
    35 \isabellestyle command is given, output is according to slanted
    36 type-writer);
    37 
    38 * support sub/super scripts (for single symbols only), input syntax is
    39 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    40 
    41 * some more standard symbols; see Appendix A of the system manual for
    42 the complete list;
    43 
    44 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    45 state; Note that presentation of goal states does not conform to
    46 actual human-readable proof documents.  Please do not include goal
    47 states into document output unless you really know what you are doing!
    48 
    49 * isatool unsymbolize tunes sources for plain ASCII communication;
    50 
    51 
    52 *** Isar ***
    53 
    54 * Pure: Isar now suffers initial goal statements to contain unbound
    55 schematic variables (this does not conform to actual readable proof
    56 documents, due to unpredictable outcome and non-compositional proof
    57 checking); users who know what they are doing may use schematic goals
    58 for Prolog-style synthesis of proven results;
    59 
    60 * Pure: assumption method (an implicit finishing) now handles actual
    61 rules as well;
    62 
    63 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    64 initial goal, declare "that" only as Pure intro (only for single
    65 steps); the "that" rule assumption may now be involved in implicit
    66 finishing, thus ".." becomes a feasible for trivial obtains;
    67 
    68 * Pure: default proof step now includes 'intro_classes'; thus trivial
    69 instance proofs may be performed by "..";
    70 
    71 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    72 statements as well;
    73 
    74 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    75 rule (as well as the assumption rule);
    76 
    77 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    78 lemmas, using the graph browser tool;
    79 
    80 * HOL: improved method 'induct' --- now handles non-atomic goals
    81 (potential INCOMPATIBILITY); tuned error handling;
    82 
    83 * HOL: cases and induct rules now provide explicit hints about the
    84 number of facts to be consumed (0 for "type" and 1 for "set" rules);
    85 any remaining facts are inserted into the goal verbatim;
    86 
    87 * HOL: local contexts (aka cases) may now contain term bindings as
    88 well; the 'cases' and 'induct' methods new provide a ?case binding for
    89 the result to be shown in each case;
    90 
    91 * HOL: added 'recdef_tc' command;
    92 
    93 
    94 *** HOL ***
    95 
    96 * HOL/Library: a collection of generic theories to be used together
    97 with main HOL; the theory loader path already includes this directory
    98 by default; the following existing theories have been moved here:
    99 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   100 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   101 
   102 * HOL basics: added overloaded operations "inverse" and "divide"
   103 (infix "/"), syntax for generic "abs" operation, generic summation
   104 operator;
   105 
   106 * HOL/typedef: simplified package, provide more useful rules (see also
   107 HOL/subset.thy);
   108 
   109 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals and 
   110 Fleuriot's mechanization of analysis;
   111 
   112 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   113 
   114 
   115 *** CTT ***
   116 
   117 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   118 "lam" is displayed as TWO lambda-symbols
   119 
   120 * CTT: theory Main now available, containing everything (that is, Bool
   121 and Arith);
   122 
   123 
   124 *** General ***
   125 
   126 * print modes "brackets" and "no_brackets" control output of nested =>
   127 (types) and ==> (props); the default behaviour is "brackets";
   128 
   129 * system: support Poly/ML 4.0 (current beta versions);
   130 
   131 * Pure: the Simplifier has been implemented properly as a derived rule
   132 outside of the actual kernel (at last!); the overall performance
   133 penalty in practical applications is about 50%, while reliability of
   134 the Isabelle inference kernel has been greatly improved;
   135 
   136 * Provers: fast_tac (and friends) now handle actual object-logic rules
   137 as assumptions as well;
   138 
   139 
   140 
   141 New in Isabelle99-1 (October 2000)
   142 ----------------------------------
   143 
   144 *** Overview of INCOMPATIBILITIES ***
   145 
   146 * HOL: simplification of natural numbers is much changed; to partly
   147 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   148 issue the following ML commands:
   149 
   150   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   151   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   152 
   153 * HOL: simplification no longer dives into case-expressions; this is
   154 controlled by "t.weak_case_cong" for each datatype t;
   155 
   156 * HOL: nat_less_induct renamed to less_induct;
   157 
   158 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   159 fixsome to patch .thy and .ML sources automatically;
   160 
   161   select_equality  -> some_equality
   162   select_eq_Ex     -> some_eq_ex
   163   selectI2EX       -> someI2_ex
   164   selectI2         -> someI2
   165   selectI          -> someI
   166   select1_equality -> some1_equality
   167   Eps_sym_eq       -> some_sym_eq_trivial
   168   Eps_eq           -> some_eq_trivial
   169 
   170 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   171 
   172 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   173 instead);
   174 
   175 * HOL: the recursion equations generated by 'recdef' are now called
   176 f.simps instead of f.rules;
   177 
   178 * HOL: qed_spec_mp now also handles bounded ALL as well;
   179 
   180 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   181 sometimes be needed;
   182 
   183 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   184 
   185 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   186 
   187 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   188 product is now "<*>" instead of "Times"; the lexicographic product is
   189 now "<*lex*>" instead of "**";
   190 
   191 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   192 of main HOL, but was unused); better use HOL's datatype package;
   193 
   194 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   195 the old syntax may be recovered as follows:
   196 
   197   syntax (symbols)
   198     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   199       (infixl "\\<oplus>" 100)
   200 
   201 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   202 
   203 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   204 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   205 internally;
   206 
   207 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   208 changed from A/r to A//r;
   209 
   210 * ZF: new treatment of arithmetic (nat & int) may break some old
   211 proofs;
   212 
   213 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   214 rulify -> rule_format, elimify -> elim_format, ...);
   215 
   216 * Isar/Provers: intro/elim/dest attributes changed; renamed
   217 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   218 should have to change intro!! to intro? only); replaced "delrule" by
   219 "rule del";
   220 
   221 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   222 
   223 * Provers: strengthened force_tac by using new first_best_tac;
   224 
   225 * LaTeX document preparation: several changes of isabelle.sty (see
   226 lib/texinputs);
   227 
   228 
   229 *** Document preparation ***
   230 
   231 * formal comments (text blocks etc.) in new-style theories may now
   232 contain antiquotations of thm/prop/term/typ/text to be presented
   233 according to latex print mode; concrete syntax is like this:
   234 @{term[show_types] "f(x) = a + x"};
   235 
   236 * isatool mkdir provides easy setup of Isabelle session directories,
   237 including proper document sources;
   238 
   239 * generated LaTeX sources are now deleted after successful run
   240 (isatool document -c); may retain a copy somewhere else via -D option
   241 of isatool usedir;
   242 
   243 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   244 style files, achieving self-contained LaTeX sources and simplifying
   245 LaTeX debugging;
   246 
   247 * old-style theories now produce (crude) LaTeX output as well;
   248 
   249 * browser info session directories are now self-contained (may be put
   250 on WWW server seperately); improved graphs of nested sessions; removed
   251 graph for 'all sessions';
   252 
   253 * several improvements in isabelle style files; \isabellestyle{it}
   254 produces fake math mode output; \isamarkupheader is now \section by
   255 default; see lib/texinputs/isabelle.sty etc.;
   256 
   257 
   258 *** Isar ***
   259 
   260 * Isar/Pure: local results and corresponding term bindings are now
   261 subject to Hindley-Milner polymorphism (similar to ML); this
   262 accommodates incremental type-inference very nicely;
   263 
   264 * Isar/Pure: new derived language element 'obtain' supports
   265 generalized existence reasoning;
   266 
   267 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   268 support accumulation of results, without applying any rules yet;
   269 useful to collect intermediate results without explicit name
   270 references, and for use with transitivity rules with more than 2
   271 premises;
   272 
   273 * Isar/Pure: scalable support for case-analysis type proofs: new
   274 'case' language element refers to local contexts symbolically, as
   275 produced by certain proof methods; internally, case names are attached
   276 to theorems as "tags";
   277 
   278 * Isar/Pure: theory command 'hide' removes declarations from
   279 class/type/const name spaces;
   280 
   281 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   282 indicate potential overloading;
   283 
   284 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   285 
   286 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   287 "{a,b,c}" instead of {a,b,c};
   288 
   289 * Isar/Pure now provides its own version of intro/elim/dest
   290 attributes; useful for building new logics, but beware of confusion
   291 with the version in Provers/classical;
   292 
   293 * Isar/Pure: the local context of (non-atomic) goals is provided via
   294 case name 'antecedent';
   295 
   296 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   297 to the current context is now done automatically);
   298 
   299 * Isar/Pure: theory command 'method_setup' provides a simple interface
   300 for definining proof methods in ML;
   301 
   302 * Isar/Provers: intro/elim/dest attributes changed; renamed
   303 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   304 most cases, one should have to change intro!! to intro? only);
   305 replaced "delrule" by "rule del";
   306 
   307 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   308 'symmetric' attribute (the latter supercedes [RS sym]);
   309 
   310 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   311 method modifier); 'simp' method: 'only:' modifier removes loopers as
   312 well (including splits);
   313 
   314 * Isar/Provers: Simplifier and Classical methods now support all kind
   315 of modifiers used in the past, including 'cong', 'iff', etc.
   316 
   317 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   318 of Simplifier and Classical reasoner);
   319 
   320 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   321 now support named cases; major packages (inductive, datatype, primrec,
   322 recdef) support case names and properly name parameters;
   323 
   324 * Isar/HOL: new transitivity rules for substitution in inequalities --
   325 monotonicity conditions are extracted to be proven at end of
   326 calculations;
   327 
   328 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   329 method anyway;
   330 
   331 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   332 split_if split_if_asm; datatype package provides theorems foo.splits =
   333 foo.split foo.split_asm for each datatype;
   334 
   335 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   336 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   337 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   338 use "(cases (simplified))" method in proper proof texts);
   339 
   340 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   341 
   342 * Isar: names of theorems etc. may be natural numbers as well;
   343 
   344 * Isar: 'pr' command: optional arguments for goals_limit and
   345 ProofContext.prems_limit; no longer prints theory contexts, but only
   346 proof states;
   347 
   348 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   349 additional print modes to be specified; e.g. "pr(latex)" will print
   350 proof state according to the Isabelle LaTeX style;
   351 
   352 * Isar: improved support for emulating tactic scripts, including proof
   353 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   354 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   355 (for HOL datatypes);
   356 
   357 * Isar: simplified (more robust) goal selection of proof methods: 1st
   358 goal, all goals, or explicit goal specifier (tactic emulation); thus
   359 'proof method scripts' have to be in depth-first order;
   360 
   361 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   362 
   363 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   364 should instead use individual commands for printing items
   365 (print_commands, print_methods etc.);
   366 
   367 * Isar: added 'nothing' --- the empty list of theorems;
   368 
   369 
   370 *** HOL ***
   371 
   372 * HOL/MicroJava: formalization of a fragment of Java, together with a
   373 corresponding virtual machine and a specification of its bytecode
   374 verifier and a lightweight bytecode verifier, including proofs of
   375 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   376 Cornelia Pusch (see also the homepage of project Bali at
   377 http://isabelle.in.tum.de/Bali/);
   378 
   379 * HOL/Algebra: new theory of rings and univariate polynomials, by
   380 Clemens Ballarin;
   381 
   382 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   383 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   384 Rasmussen;
   385 
   386 * HOL/Lattice: fundamental concepts of lattice theory and order
   387 structures, including duals, properties of bounds versus algebraic
   388 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   389 Theorem for complete lattices etc.; may also serve as a demonstration
   390 for abstract algebraic reasoning using axiomatic type classes, and
   391 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   392 
   393 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   394 von Oheimb;
   395 
   396 * HOL/IMPP: extension of IMP with local variables and mutually
   397 recursive procedures, by David von Oheimb;
   398 
   399 * HOL/Lambda: converted into new-style theory and document;
   400 
   401 * HOL/ex/Multiquote: example of multiple nested quotations and
   402 anti-quotations -- basically a generalized version of de-Bruijn
   403 representation; very useful in avoiding lifting of operations;
   404 
   405 * HOL/record: added general record equality rule to simpset; fixed
   406 select-update simplification procedure to handle extended records as
   407 well; admit "r" as field name;
   408 
   409 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   410 other numeric types and also as the identity of groups, rings, etc.;
   411 
   412 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   413 Types nat and int belong to this axclass;
   414 
   415 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   416    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   417    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   418   two terms #m*u and #n*u are replaced by #(m+n)*u
   419     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   420   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   421     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   422 
   423 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   424 powerful prover for predicate logic but knows nothing of clasets; see
   425 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   426 
   427 * HOL: new version of "case_tac" subsumes both boolean case split and
   428 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   429 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   430 
   431 * HOL: simplification no longer dives into case-expressions: only the
   432 selector expression is simplified, but not the remaining arms; to
   433 enable full simplification of case-expressions for datatype t, you may
   434 remove t.weak_case_cong from the simpset, either globally (Delcongs
   435 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   436 
   437 * HOL/recdef: the recursion equations generated by 'recdef' for
   438 function 'f' are now called f.simps instead of f.rules; if all
   439 termination conditions are proved automatically, these simplification
   440 rules are added to the simpset, as in primrec; rules may be named
   441 individually as well, resulting in a separate list of theorems for
   442 each equation;
   443 
   444 * HOL/While is a new theory that provides a while-combinator. It
   445 permits the definition of tail-recursive functions without the
   446 provision of a termination measure. The latter is necessary once the
   447 invariant proof rule for while is applied.
   448 
   449 * HOL: new (overloaded) notation for the set of elements below/above
   450 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   451 
   452 * HOL: theorems impI, allI, ballI bound as "strip";
   453 
   454 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   455 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   456 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   457 
   458 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   459 
   460 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   461 main HOL, but was unused);
   462 
   463 * HOL: fewer consts declared as global (e.g. have to refer to
   464 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   465 
   466 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   467 in case of overlap with user translations (e.g. judgements over
   468 tuples); (note that the underlying logical represenation is still
   469 bogus);
   470 
   471 
   472 *** ZF ***
   473 
   474 * ZF: simplification automatically cancels common terms in arithmetic
   475 expressions over nat and int;
   476 
   477 * ZF: new treatment of nat to minimize type-checking: all operators
   478 coerce their operands to a natural number using the function natify,
   479 making the algebraic laws unconditional;
   480 
   481 * ZF: as above, for int: operators coerce their operands to an integer
   482 using the function intify;
   483 
   484 * ZF: the integer library now contains many of the usual laws for the
   485 orderings, including $<=, and monotonicity laws for $+ and $*;
   486 
   487 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   488 simplification;
   489 
   490 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   491 to the simplifier and classical reasoner simultaneously;
   492 
   493 
   494 *** General ***
   495 
   496 * Provers: blast_tac now handles actual object-logic rules as
   497 assumptions; note that auto_tac uses blast_tac internally as well;
   498 
   499 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   500 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   501 
   502 * Provers: delrules now handles destruct rules as well (no longer need
   503 explicit make_elim);
   504 
   505 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   506   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   507 use instead the strong form,
   508   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   509 in HOL, FOL and ZF the function cla_make_elim will create such rules
   510 from destruct-rules;
   511 
   512 * Provers: Simplifier.easy_setup provides a fast path to basic
   513 Simplifier setup for new object-logics;
   514 
   515 * Pure: AST translation rules no longer require constant head on LHS;
   516 
   517 * Pure: improved name spaces: ambiguous output is qualified; support
   518 for hiding of names;
   519 
   520 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   521 XSYMBOL_HOME; no longer need to do manual configuration in most
   522 situations;
   523 
   524 * system: compression of ML heaps images may now be controlled via -c
   525 option of isabelle and isatool usedir (currently only observed by
   526 Poly/ML);
   527 
   528 * system: isatool installfonts may handle X-Symbol fonts as well (very
   529 useful for remote X11);
   530 
   531 * system: provide TAGS file for Isabelle sources;
   532 
   533 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   534 order;
   535 
   536 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   537 timing flag supersedes proof_timing and Toplevel.trace;
   538 
   539 * ML: new combinators |>> and |>>> for incremental transformations
   540 with secondary results (e.g. certain theory extensions):
   541 
   542 * ML: PureThy.add_defs gets additional argument to indicate potential
   543 overloading (usually false);
   544 
   545 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   546 results;
   547 
   548 
   549 
   550 New in Isabelle99 (October 1999)
   551 --------------------------------
   552 
   553 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   554 
   555 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   556 are no longer simplified.  (This allows the simplifier to unfold recursive
   557 functional programs.)  To restore the old behaviour, declare
   558 
   559     Delcongs [if_weak_cong];
   560 
   561 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   562 complement;
   563 
   564 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   565 
   566 * HOL/datatype: mutual_induct_tac no longer exists --
   567   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   568 
   569 * HOL/typedef: fixed type inference for representing set; type
   570 arguments now have to occur explicitly on the rhs as type constraints;
   571 
   572 * ZF: The con_defs part of an inductive definition may no longer refer
   573 to constants declared in the same theory;
   574 
   575 * HOL, ZF: the function mk_cases, generated by the inductive
   576 definition package, has lost an argument.  To simplify its result, it
   577 uses the default simpset instead of a supplied list of theorems.
   578 
   579 * HOL/List: the constructors of type list are now Nil and Cons;
   580 
   581 * Simplifier: the type of the infix ML functions
   582         setSSolver addSSolver setSolver addSolver
   583 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   584 for packaging solvers. A solver is created via
   585         mk_solver: string -> (thm list -> int -> tactic) -> solver
   586 where the string argument is only a comment.
   587 
   588 
   589 *** Proof tools ***
   590 
   591 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   592 decision procedure for linear arithmetic. Currently it is used for
   593 types `nat', `int', and `real' in HOL (see below); it can, should and
   594 will be instantiated for other types and logics as well.
   595 
   596 * The simplifier now accepts rewrite rules with flexible heads, eg
   597      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   598   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   599   matching.
   600 
   601 
   602 *** General ***
   603 
   604 * New Isabelle/Isar subsystem provides an alternative to traditional
   605 tactical theorem proving; together with the ProofGeneral/isar user
   606 interface it offers an interactive environment for developing human
   607 readable proof documents (Isar == Intelligible semi-automated
   608 reasoning); for further information see isatool doc isar-ref,
   609 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   610 
   611 * improved and simplified presentation of theories: better HTML markup
   612 (including colors), graph views in several sizes; isatool usedir now
   613 provides a proper interface for user theories (via -P option); actual
   614 document preparation based on (PDF)LaTeX is available as well (for
   615 new-style theories only); see isatool doc system for more information;
   616 
   617 * native support for Proof General, both for classic Isabelle and
   618 Isabelle/Isar;
   619 
   620 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   621 using the graph browser tool;
   622 
   623 * Isabelle manuals now also available as PDF;
   624 
   625 * theory loader rewritten from scratch (may not be fully
   626 bug-compatible); old loadpath variable has been replaced by show_path,
   627 add_path, del_path, reset_path functions; new operations such as
   628 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   629 isatool doc ref);
   630 
   631 * improved isatool install: option -k creates KDE application icon,
   632 option -p DIR installs standalone binaries;
   633 
   634 * added ML_PLATFORM setting (useful for cross-platform installations);
   635 more robust handling of platform specific ML images for SML/NJ;
   636 
   637 * the settings environment is now statically scoped, i.e. it is never
   638 created again in sub-processes invoked from isabelle, isatool, or
   639 Isabelle;
   640 
   641 * path element specification '~~' refers to '$ISABELLE_HOME';
   642 
   643 * in locales, the "assumes" and "defines" parts may be omitted if
   644 empty;
   645 
   646 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   647 long arrows);
   648 
   649 * new print_mode "HTML";
   650 
   651 * new flag show_tags controls display of tags of theorems (which are
   652 basically just comments that may be attached by some tools);
   653 
   654 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   655 mode and goal output format:
   656 
   657 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   658 244c244
   659 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   660 ---
   661 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   662 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   663 181c181
   664 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   665 ---
   666 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   667 
   668 * function bind_thms stores lists of theorems (cf. bind_thm);
   669 
   670 * new shorthand tactics ftac, eatac, datac, fatac;
   671 
   672 * qed (and friends) now accept "" as result name; in that case the
   673 theorem is not stored, but proper checks and presentation of the
   674 result still apply;
   675 
   676 * theorem database now also indexes constants "Trueprop", "all",
   677 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   678 
   679 
   680 *** HOL ***
   681 
   682 ** HOL arithmetic **
   683 
   684 * There are now decision procedures for linear arithmetic over nat and
   685 int:
   686 
   687 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   688 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   689 are treated as atomic; subformulae not involving type `nat' or `int'
   690 are ignored; quantified subformulae are ignored unless they are
   691 positive universal or negative existential. The tactic has to be
   692 invoked by hand and can be a little bit slow. In particular, the
   693 running time is exponential in the number of occurrences of `min' and
   694 `max', and `-' on `nat'.
   695 
   696 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   697 (negated) (in)equalities among the premises and the conclusion into
   698 account (i.e. no compound formulae) and does not know about `min' and
   699 `max', and `-' on `nat'. It is fast and is used automatically by the
   700 simplifier.
   701 
   702 NB: At the moment, these decision procedures do not cope with mixed
   703 nat/int formulae where the two parts interact, such as `m < n ==>
   704 int(m) < int(n)'.
   705 
   706 * HOL/Numeral provides a generic theory of numerals (encoded
   707 efficiently as bit strings); setup for types nat/int/real is in place;
   708 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   709 int, existing theories and proof scripts may require a few additional
   710 type constraints;
   711 
   712 * integer division and remainder can now be performed on constant
   713 arguments;
   714 
   715 * many properties of integer multiplication, division and remainder
   716 are now available;
   717 
   718 * An interface to the Stanford Validity Checker (SVC) is available through the
   719 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   720 are proved automatically.  SVC must be installed separately, and its results
   721 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   722 invocation of the underlying oracle).  For SVC see
   723   http://verify.stanford.edu/SVC
   724 
   725 * IsaMakefile: the HOL-Real target now builds an actual image;
   726 
   727 
   728 ** HOL misc **
   729 
   730 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   731 (in Isabelle/Isar) -- by Gertrud Bauer;
   732 
   733 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   734 analysis for assembly languages with subtypes;
   735 
   736 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   737 -- avoids syntactic ambiguities and treats state, transition, and
   738 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   739 changed syntax and (many) tactics;
   740 
   741 * HOL/inductive: Now also handles more general introduction rules such
   742   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   743   theorems are now maintained within the theory (maintained via the
   744   "mono" attribute);
   745 
   746 * HOL/datatype: Now also handles arbitrarily branching datatypes
   747   (using function types) such as
   748 
   749   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   750 
   751 * HOL/record: record_simproc (part of the default simpset) takes care
   752 of selectors applied to updated records; record_split_tac is no longer
   753 part of the default claset; update_defs may now be removed from the
   754 simpset in many cases; COMPATIBILITY: old behavior achieved by
   755 
   756   claset_ref () := claset() addSWrapper record_split_wrapper;
   757   Delsimprocs [record_simproc]
   758 
   759 * HOL/typedef: fixed type inference for representing set; type
   760 arguments now have to occur explicitly on the rhs as type constraints;
   761 
   762 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   763 names rather than an ML expression;
   764 
   765 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   766 supplied later.  Program schemes can be defined, such as
   767     "While B C s = (if B s then While B C (C s) else s)"
   768 where the well-founded relation can be chosen after B and C have been given.
   769 
   770 * HOL/List: the constructors of type list are now Nil and Cons;
   771 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   772 course, ML tools referring to List.list.op # etc. have to be adapted;
   773 
   774 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   775 disabled by default; run isabelle with option -m HOL to get back to
   776 the original Gordon/HOL-style output;
   777 
   778 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   779 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   780 
   781 * HOL basic syntax simplified (more orthogonal): all variants of
   782 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   783 Eps operator is provided as well: "SOME x. P[x]";
   784 
   785 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   786 
   787 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   788 thus available for user theories;
   789 
   790 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   791 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   792 time;
   793 
   794 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   795 several times and then mp;
   796 
   797 
   798 *** LK ***
   799 
   800 * the notation <<...>> is now available as a notation for sequences of
   801 formulas;
   802 
   803 * the simplifier is now installed
   804 
   805 * the axiom system has been generalized (thanks to Soren Heilmann)
   806 
   807 * the classical reasoner now has a default rule database
   808 
   809 
   810 *** ZF ***
   811 
   812 * new primrec section allows primitive recursive functions to be given
   813 directly (as in HOL) over datatypes and the natural numbers;
   814 
   815 * new tactics induct_tac and exhaust_tac for induction (or case
   816 analysis) over datatypes and the natural numbers;
   817 
   818 * the datatype declaration of type T now defines the recursor T_rec;
   819 
   820 * simplification automatically does freeness reasoning for datatype
   821 constructors;
   822 
   823 * automatic type-inference, with AddTCs command to insert new
   824 type-checking rules;
   825 
   826 * datatype introduction rules are now added as Safe Introduction rules
   827 to the claset;
   828 
   829 * the syntax "if P then x else y" is now available in addition to
   830 if(P,x,y);
   831 
   832 
   833 *** Internal programming interfaces ***
   834 
   835 * tuned simplifier trace output; new flag debug_simp;
   836 
   837 * structures Vartab / Termtab (instances of TableFun) offer efficient
   838 tables indexed by indexname_ord / term_ord (compatible with aconv);
   839 
   840 * AxClass.axclass_tac lost the theory argument;
   841 
   842 * tuned current_goals_markers semantics: begin / end goal avoids
   843 printing empty lines;
   844 
   845 * removed prs and prs_fn hook, which was broken because it did not
   846 include \n in its semantics, forcing writeln to add one
   847 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   848 string -> unit if you really want to output text without newline;
   849 
   850 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   851 plain output, interface builders may have to enable 'isabelle_font'
   852 mode to get Isabelle font glyphs as before;
   853 
   854 * refined token_translation interface; INCOMPATIBILITY: output length
   855 now of type real instead of int;
   856 
   857 * theory loader actions may be traced via new ThyInfo.add_hook
   858 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   859 your own database of information attached to *whole* theories -- as
   860 opposed to intra-theory data slots offered via TheoryDataFun;
   861 
   862 * proper handling of dangling sort hypotheses (at last!);
   863 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   864 extra sort hypotheses that can be witnessed from the type signature;
   865 the force_strip_shyps flag is gone, any remaining shyps are simply
   866 left in the theorem (with a warning issued by strip_shyps_warning);
   867 
   868 
   869 
   870 New in Isabelle98-1 (October 1998)
   871 ----------------------------------
   872 
   873 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   874 
   875 * several changes of automated proof tools;
   876 
   877 * HOL: major changes to the inductive and datatype packages, including
   878 some minor incompatibilities of theory syntax;
   879 
   880 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   881 called `inj_on';
   882 
   883 * HOL: removed duplicate thms in Arith:
   884   less_imp_add_less  should be replaced by  trans_less_add1
   885   le_imp_add_le      should be replaced by  trans_le_add1
   886 
   887 * HOL: unary minus is now overloaded (new type constraints may be
   888 required);
   889 
   890 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   891 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   892 now taken as an integer constant.
   893 
   894 * Pure: ML function 'theory_of' renamed to 'theory';
   895 
   896 
   897 *** Proof tools ***
   898 
   899 * Simplifier:
   900   1. Asm_full_simp_tac is now more aggressive.
   901      1. It will sometimes reorient premises if that increases their power to
   902         simplify.
   903      2. It does no longer proceed strictly from left to right but may also
   904         rotate premises to achieve further simplification.
   905      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   906      old Asm_full_simp_tac in that it does not rotate premises.
   907   2. The simplifier now knows a little bit about nat-arithmetic.
   908 
   909 * Classical reasoner: wrapper mechanism for the classical reasoner now
   910 allows for selected deletion of wrappers, by introduction of names for
   911 wrapper functionals.  This implies that addbefore, addSbefore,
   912 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   913 and that adding two tactics with the same name overwrites the first
   914 one (emitting a warning).
   915   type wrapper = (int -> tactic) -> (int -> tactic)
   916   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   917   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   918   delWrapper, delSWrapper: claset *  string            -> claset
   919   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   920 
   921 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   922 semantics; addbefore now affects only the unsafe part of step_tac
   923 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   924 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   925 by Force_tac;
   926 
   927 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   928 compWrapper; added safe wrapper (and access functions for it);
   929 
   930 * HOL/split_all_tac is now much faster and fails if there is nothing
   931 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   932 and the names of the automatically generated variables have changed.
   933 split_all_tac has moved within claset() from unsafe wrappers to safe
   934 wrappers, which means that !!-bound variables are split much more
   935 aggressively, and safe_tac and clarify_tac now split such variables.
   936 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   937 Note: the same holds for record_split_tac, which does the job of
   938 split_all_tac for record fields.
   939 
   940 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   941 permanently to the default simpset using Addsplits just like
   942 Addsimps. They can be removed via Delsplits just like
   943 Delsimps. Lower-case versions are also available.
   944 
   945 * HOL/Simplifier: The rule split_if is now part of the default
   946 simpset. This means that the simplifier will eliminate all occurrences
   947 of if-then-else in the conclusion of a goal. To prevent this, you can
   948 either remove split_if completely from the default simpset by
   949 `Delsplits [split_if]' or remove it in a specific call of the
   950 simplifier using `... delsplits [split_if]'.  You can also add/delete
   951 other case splitting rules to/from the default simpset: every datatype
   952 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   953 t is the name of the datatype).
   954 
   955 * Classical reasoner / Simplifier combination: new force_tac (and
   956 derivatives Force_tac, force) combines rewriting and classical
   957 reasoning (and whatever other tools) similarly to auto_tac, but is
   958 aimed to solve the given subgoal completely.
   959 
   960 
   961 *** General ***
   962 
   963 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   964 and `goalw': the theory is no longer needed as an explicit argument -
   965 the current theory context is used; assumptions are no longer returned
   966 at the ML-level unless one of them starts with ==> or !!; it is
   967 recommended to convert to these new commands using isatool fixgoal
   968 (backup your sources first!);
   969 
   970 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   971 the current theory context, and 'theory' to lookup stored theories;
   972 
   973 * new theory section 'locale' for declaring constants, assumptions and
   974 definitions that have local scope;
   975 
   976 * new theory section 'nonterminals' for purely syntactic types;
   977 
   978 * new theory section 'setup' for generic ML setup functions
   979 (e.g. package initialization);
   980 
   981 * the distribution now includes Isabelle icons: see
   982 lib/logo/isabelle-{small,tiny}.xpm;
   983 
   984 * isatool install - install binaries with absolute references to
   985 ISABELLE_HOME/bin;
   986 
   987 * isatool logo -- create instances of the Isabelle logo (as EPS);
   988 
   989 * print mode 'emacs' reserved for Isamode;
   990 
   991 * support multiple print (ast) translations per constant name;
   992 
   993 * theorems involving oracles are now printed with a suffixed [!];
   994 
   995 
   996 *** HOL ***
   997 
   998 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   999 
  1000 * HOL/inductive package reorganized and improved: now supports mutual
  1001 definitions such as
  1002 
  1003   inductive EVEN ODD
  1004     intrs
  1005       null "0 : EVEN"
  1006       oddI "n : EVEN ==> Suc n : ODD"
  1007       evenI "n : ODD ==> Suc n : EVEN"
  1008 
  1009 new theorem list "elims" contains an elimination rule for each of the
  1010 recursive sets; inductive definitions now handle disjunctive premises
  1011 correctly (also ZF);
  1012 
  1013 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1014 "mutual_induct" no longer exists - the induction rule is always
  1015 contained in "induct";
  1016 
  1017 
  1018 * HOL/datatype package re-implemented and greatly improved: now
  1019 supports mutually recursive datatypes such as
  1020 
  1021   datatype
  1022     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1023             | SUM ('a aexp) ('a aexp)
  1024             | DIFF ('a aexp) ('a aexp)
  1025             | NUM 'a
  1026   and
  1027     'a bexp = LESS ('a aexp) ('a aexp)
  1028             | AND ('a bexp) ('a bexp)
  1029             | OR ('a bexp) ('a bexp)
  1030 
  1031 as well as indirectly recursive datatypes such as
  1032 
  1033   datatype
  1034     ('a, 'b) term = Var 'a
  1035                   | App 'b ((('a, 'b) term) list)
  1036 
  1037 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1038 induction on mutually / indirectly recursive datatypes.
  1039 
  1040 Primrec equations are now stored in theory and can be accessed via
  1041 <function_name>.simps.
  1042 
  1043 INCOMPATIBILITIES:
  1044 
  1045   - Theories using datatypes must now have theory Datatype as an
  1046     ancestor.
  1047   - The specific <typename>.induct_tac no longer exists - use the
  1048     generic induct_tac instead.
  1049   - natE has been renamed to nat.exhaust - use exhaust_tac
  1050     instead of res_inst_tac ... natE. Note that the variable
  1051     names in nat.exhaust differ from the names in natE, this
  1052     may cause some "fragile" proofs to fail.
  1053   - The theorems split_<typename>_case and split_<typename>_case_asm
  1054     have been renamed to <typename>.split and <typename>.split_asm.
  1055   - Since default sorts of type variables are now handled correctly,
  1056     some datatype definitions may have to be annotated with explicit
  1057     sort constraints.
  1058   - Primrec definitions no longer require function name and type
  1059     of recursive argument.
  1060 
  1061 Consider using isatool fixdatatype to adapt your theories and proof
  1062 scripts to the new package (backup your sources first!).
  1063 
  1064 
  1065 * HOL/record package: considerably improved implementation; now
  1066 includes concrete syntax for record types, terms, updates; theorems
  1067 for surjective pairing and splitting !!-bound record variables; proof
  1068 support is as follows:
  1069 
  1070   1) standard conversions (selectors or updates applied to record
  1071 constructor terms) are part of the standard simpset;
  1072 
  1073   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1074 made part of standard simpset and claset via addIffs;
  1075 
  1076   3) a tactic for record field splitting (record_split_tac) is part of
  1077 the standard claset (addSWrapper);
  1078 
  1079 To get a better idea about these rules you may retrieve them via
  1080 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1081 the name of your record type.
  1082 
  1083 The split tactic 3) conceptually simplifies by the following rule:
  1084 
  1085   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1086 
  1087 Thus any record variable that is bound by meta-all will automatically
  1088 blow up into some record constructor term, consequently the
  1089 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1090 solve record problems automatically.
  1091 
  1092 
  1093 * reorganized the main HOL image: HOL/Integ and String loaded by
  1094 default; theory Main includes everything;
  1095 
  1096 * automatic simplification of integer sums and comparisons, using cancellation;
  1097 
  1098 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1099 
  1100 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1101 
  1102 * many new identities for unions, intersections, set difference, etc.;
  1103 
  1104 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1105 called split_if, split_split, split_sum_case and split_nat_case (to go
  1106 with add/delsplits);
  1107 
  1108 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1109 (?x::unit) = (); this is made part of the default simpset, which COULD
  1110 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1111 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1112 unit_abs_eta_conv is added in order to counter the effect of
  1113 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1114 %u.f();
  1115 
  1116 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1117 makes more sense);
  1118 
  1119 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1120   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1121   disjointness reasoning but breaking a few old proofs.
  1122 
  1123 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1124 to 'converse' from 'inverse' (for compatibility with ZF and some
  1125 literature);
  1126 
  1127 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1128 the well-founded relation;
  1129 
  1130 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1131     Compl A.  The "Compl" syntax remains available as input syntax for this
  1132     release ONLY.
  1133 
  1134 * HOL/Update: new theory of function updates:
  1135     f(a:=b) == %x. if x=a then b else f x
  1136 may also be iterated as in f(a:=b,c:=d,...);
  1137 
  1138 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1139 
  1140 * HOL/List:
  1141   - new function list_update written xs[i:=v] that updates the i-th
  1142     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1143   - new function `upt' written [i..j(] which generates the list
  1144     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1145     bound write [i..j], which is a shorthand for [i..j+1(].
  1146   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1147 
  1148 * HOL/Arith:
  1149   - removed 'pred' (predecessor) function;
  1150   - generalized some theorems about n-1;
  1151   - many new laws about "div" and "mod";
  1152   - new laws about greatest common divisors (see theory ex/Primes);
  1153 
  1154 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1155 instead of "inverse";
  1156 
  1157 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1158   of the multiset ordering;
  1159 
  1160 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1161   (not included by default);
  1162 
  1163 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1164 
  1165 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1166   programs, i.e. different program variables may have different types.
  1167 
  1168 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1169   [previously, this check worked only if the rewrite rule was unconditional]
  1170   Now rew can involve either definitions or equalities (either == or =).
  1171 
  1172 
  1173 *** ZF ***
  1174 
  1175 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1176   only the theorems proved on ZF.ML;
  1177 
  1178 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1179   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1180   disjointness reasoning but breaking a few old proofs.
  1181 
  1182 * ZF/Update: new theory of function updates
  1183     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1184   may also be iterated as in f(a:=b,c:=d,...);
  1185 
  1186 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1187 
  1188 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1189   [previously, this check worked only if the rewrite rule was unconditional]
  1190   Now rew can involve either definitions or equalities (either == or =).
  1191 
  1192 * case_tac provided for compatibility with HOL
  1193     (like the old excluded_middle_tac, but with subgoals swapped)
  1194 
  1195 
  1196 *** Internal programming interfaces ***
  1197 
  1198 * Pure: several new basic modules made available for general use, see
  1199 also src/Pure/README;
  1200 
  1201 * improved the theory data mechanism to support encapsulation (data
  1202 kind name replaced by private Object.kind, acting as authorization
  1203 key); new type-safe user interface via functor TheoryDataFun; generic
  1204 print_data function becomes basically useless;
  1205 
  1206 * removed global_names compatibility flag -- all theory declarations
  1207 are qualified by default;
  1208 
  1209 * module Pure/Syntax now offers quote / antiquote translation
  1210 functions (useful for Hoare logic etc. with implicit dependencies);
  1211 see HOL/ex/Antiquote for an example use;
  1212 
  1213 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1214 cterm -> thm;
  1215 
  1216 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1217 subgoal;
  1218 
  1219 * Display.print_goals function moved to Locale.print_goals;
  1220 
  1221 * standard print function for goals supports current_goals_markers
  1222 variable for marking begin of proof, end of proof, start of goal; the
  1223 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1224 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1225 for example;
  1226 
  1227 
  1228 
  1229 New in Isabelle98 (January 1998)
  1230 --------------------------------
  1231 
  1232 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1233 
  1234 * changed lexical syntax of terms / types: dots made part of long
  1235 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1236 
  1237 * simpset (and claset) reference variable replaced by functions
  1238 simpset / simpset_ref;
  1239 
  1240 * no longer supports theory aliases (via merge) and non-trivial
  1241 implicit merge of thms' signatures;
  1242 
  1243 * most internal names of constants changed due to qualified names;
  1244 
  1245 * changed Pure/Sequence interface (see Pure/seq.ML);
  1246 
  1247 
  1248 *** General Changes ***
  1249 
  1250 * hierachically structured name spaces (for consts, types, axms, thms
  1251 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1252 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1253 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1254 long_names for fully qualified output names; NOTE: ML programs
  1255 (special tactics, packages etc.) referring to internal names may have
  1256 to be adapted to cope with fully qualified names; in case of severe
  1257 backward campatibility problems try setting 'global_names' at compile
  1258 time to have enrything declared within a flat name space; one may also
  1259 fine tune name declarations in theories via the 'global' and 'local'
  1260 section;
  1261 
  1262 * reimplemented the implicit simpset and claset using the new anytype
  1263 data filed in signatures; references simpset:simpset ref etc. are
  1264 replaced by functions simpset:unit->simpset and
  1265 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1266 to patch your ML files accordingly;
  1267 
  1268 * HTML output now includes theory graph data for display with Java
  1269 applet or isatool browser; data generated automatically via isatool
  1270 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1271 
  1272 * defs may now be conditional; improved rewrite_goals_tac to handle
  1273 conditional equations;
  1274 
  1275 * defs now admits additional type arguments, using TYPE('a) syntax;
  1276 
  1277 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1278 creates a new theory node; implicit merge of thms' signatures is
  1279 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1280 transfer:theory->thm->thm in (rare) cases;
  1281 
  1282 * improved handling of draft signatures / theories; draft thms (and
  1283 ctyps, cterms) are automatically promoted to real ones;
  1284 
  1285 * slightly changed interfaces for oracles: admit many per theory, named
  1286 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1287 
  1288 * print_goals: optional output of const types (set show_consts and
  1289 show_types);
  1290 
  1291 * improved output of warnings (###) and errors (***);
  1292 
  1293 * subgoal_tac displays a warning if the new subgoal has type variables;
  1294 
  1295 * removed old README and Makefiles;
  1296 
  1297 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1298 
  1299 * removed obsolete init_pps and init_database;
  1300 
  1301 * deleted the obsolete tactical STATE, which was declared by
  1302     fun STATE tacfun st = tacfun st st;
  1303 
  1304 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1305 (which abbreviates $HOME);
  1306 
  1307 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1308 use isatool fixseq to adapt your ML programs (this works for fully
  1309 qualified references to the Sequence structure only!);
  1310 
  1311 * use_thy no longer requires writable current directory; it always
  1312 reloads .ML *and* .thy file, if either one is out of date;
  1313 
  1314 
  1315 *** Classical Reasoner ***
  1316 
  1317 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1318 tactics that use classical reasoning to simplify a subgoal without
  1319 splitting it into several subgoals;
  1320 
  1321 * Safe_tac: like safe_tac but uses the default claset;
  1322 
  1323 
  1324 *** Simplifier ***
  1325 
  1326 * added simplification meta rules:
  1327     (asm_)(full_)simplify: simpset -> thm -> thm;
  1328 
  1329 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1330 logics (again);
  1331 
  1332 * added prems argument to simplification procedures;
  1333 
  1334 * HOL, FOL, ZF: added infix function `addsplits':
  1335   instead of `<simpset> setloop (split_tac <thms>)'
  1336   you can simply write `<simpset> addsplits <thms>'
  1337 
  1338 
  1339 *** Syntax ***
  1340 
  1341 * TYPE('a) syntax for type reflection terms;
  1342 
  1343 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1344 
  1345 * pretty printer: changed order of mixfix annotation preference (again!);
  1346 
  1347 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1348 
  1349 
  1350 *** HOL ***
  1351 
  1352 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1353   with `addloop' of the simplifier to faciliate case splitting in premises.
  1354 
  1355 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1356 
  1357 * HOL/Auth: new protocol proofs including some for the Internet
  1358   protocol TLS;
  1359 
  1360 * HOL/Map: new theory of `maps' a la VDM;
  1361 
  1362 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1363 cancelling out common nat summands from =, <, <= (in)equalities, or
  1364 differences; simplification procedures nat_cancel_factor for
  1365 cancelling common factor from =, <, <= (in)equalities over natural
  1366 sums; nat_cancel contains both kinds of procedures, it is installed by
  1367 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1368 
  1369 * HOL/simplifier: terms of the form
  1370   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1371   are rewritten to
  1372   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1373   and those of the form
  1374   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1375   are rewritten to
  1376   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1377 
  1378 * HOL/datatype
  1379   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1380 
  1381   P(t_case f1 ... fn x) =
  1382      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1383         ...
  1384        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1385      )
  1386 
  1387   and a theorem `split_t_case_asm' of the form
  1388 
  1389   P(t_case f1 ... fn x) =
  1390     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1391         ...
  1392        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1393      )
  1394   which can be added to a simpset via `addsplits'. The existing theorems
  1395   expand_list_case and expand_option_case have been renamed to
  1396   split_list_case and split_option_case.
  1397 
  1398 * HOL/Arithmetic:
  1399   - `pred n' is automatically converted to `n-1'.
  1400     Users are strongly encouraged not to use `pred' any longer,
  1401     because it will disappear altogether at some point.
  1402   - Users are strongly encouraged to write "0 < n" rather than
  1403     "n ~= 0". Theorems and proof tools have been modified towards this
  1404     `standard'.
  1405 
  1406 * HOL/Lists:
  1407   the function "set_of_list" has been renamed "set" (and its theorems too);
  1408   the function "nth" now takes its arguments in the reverse order and
  1409   has acquired the infix notation "!" as in "xs!n".
  1410 
  1411 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1412 
  1413 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1414   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1415 
  1416 * HOL/record: extensible records with schematic structural subtyping
  1417 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1418 still lacks various theorems and concrete record syntax;
  1419 
  1420 
  1421 *** HOLCF ***
  1422 
  1423 * removed "axioms" and "generated by" sections;
  1424 
  1425 * replaced "ops" section by extended "consts" section, which is capable of
  1426   handling the continuous function space "->" directly;
  1427 
  1428 * domain package:
  1429   . proves theorems immediately and stores them in the theory,
  1430   . creates hierachical name space,
  1431   . now uses normal mixfix annotations (instead of cinfix...),
  1432   . minor changes to some names and values (for consistency),
  1433   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1434   . separator between mutual domain defs: changed "," to "and",
  1435   . improved handling of sort constraints;  now they have to
  1436     appear on the left-hand side of the equations only;
  1437 
  1438 * fixed LAM <x,y,zs>.b syntax;
  1439 
  1440 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1441 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1442 
  1443 
  1444 *** FOL and ZF ***
  1445 
  1446 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1447   with `addloop' of the simplifier to faciliate case splitting in premises.
  1448 
  1449 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1450 in HOL, they strip ALL and --> from proved theorems;
  1451 
  1452 
  1453 
  1454 New in Isabelle94-8 (May 1997)
  1455 ------------------------------
  1456 
  1457 *** General Changes ***
  1458 
  1459 * new utilities to build / run / maintain Isabelle etc. (in parts
  1460 still somewhat experimental); old Makefiles etc. still functional;
  1461 
  1462 * new 'Isabelle System Manual';
  1463 
  1464 * INSTALL text, together with ./configure and ./build scripts;
  1465 
  1466 * reimplemented type inference for greater efficiency, better error
  1467 messages and clean internal interface;
  1468 
  1469 * prlim command for dealing with lots of subgoals (an easier way of
  1470 setting goals_limit);
  1471 
  1472 
  1473 *** Syntax ***
  1474 
  1475 * supports alternative (named) syntax tables (parser and pretty
  1476 printer); internal interface is provided by add_modesyntax(_i);
  1477 
  1478 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1479 be used in conjunction with the Isabelle symbol font; uses the
  1480 "symbols" syntax table;
  1481 
  1482 * added token_translation interface (may translate name tokens in
  1483 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1484 the current print_mode); IMPORTANT: user print translation functions
  1485 are responsible for marking newly introduced bounds
  1486 (Syntax.mark_boundT);
  1487 
  1488 * token translations for modes "xterm" and "xterm_color" that display
  1489 names in bold, underline etc. or colors (which requires a color
  1490 version of xterm);
  1491 
  1492 * infixes may now be declared with names independent of their syntax;
  1493 
  1494 * added typed_print_translation (like print_translation, but may
  1495 access type of constant);
  1496 
  1497 
  1498 *** Classical Reasoner ***
  1499 
  1500 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1501 some limitations.  Blast_tac...
  1502   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1503   + ignores elimination rules that don't have the correct format
  1504         (the conclusion MUST be a formula variable)
  1505   + ignores types, which can make HOL proofs fail
  1506   + rules must not require higher-order unification, e.g. apply_type in ZF
  1507     [message "Function Var's argument not a bound variable" relates to this]
  1508   + its proof strategy is more general but can actually be slower
  1509 
  1510 * substitution with equality assumptions no longer permutes other
  1511 assumptions;
  1512 
  1513 * minor changes in semantics of addafter (now called addaltern); renamed
  1514 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1515 (and access functions for it);
  1516 
  1517 * improved combination of classical reasoner and simplifier:
  1518   + functions for handling clasimpsets
  1519   + improvement of addss: now the simplifier is called _after_ the
  1520     safe steps.
  1521   + safe variant of addss called addSss: uses safe simplifications
  1522     _during_ the safe steps. It is more complete as it allows multiple
  1523     instantiations of unknowns (e.g. with slow_tac).
  1524 
  1525 *** Simplifier ***
  1526 
  1527 * added interface for simplification procedures (functions that
  1528 produce *proven* rewrite rules on the fly, depending on current
  1529 redex);
  1530 
  1531 * ordering on terms as parameter (used for ordered rewriting);
  1532 
  1533 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1534 
  1535 * the solver is now split into a safe and an unsafe part.
  1536 This should be invisible for the normal user, except that the
  1537 functions setsolver and addsolver have been renamed to setSolver and
  1538 addSolver; added safe_asm_full_simp_tac;
  1539 
  1540 
  1541 *** HOL ***
  1542 
  1543 * a generic induction tactic `induct_tac' which works for all datatypes and
  1544 also for type `nat';
  1545 
  1546 * a generic case distinction tactic `exhaust_tac' which works for all
  1547 datatypes and also for type `nat';
  1548 
  1549 * each datatype comes with a function `size';
  1550 
  1551 * patterns in case expressions allow tuple patterns as arguments to
  1552 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1553 
  1554 * primrec now also works with type nat;
  1555 
  1556 * recdef: a new declaration form, allows general recursive functions to be
  1557 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1558 
  1559 * the constant for negation has been renamed from "not" to "Not" to
  1560 harmonize with FOL, ZF, LK, etc.;
  1561 
  1562 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1563 infinite lists;
  1564 
  1565 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1566 
  1567 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1568 problems in commutative rings, using axiomatic type classes for + and *;
  1569 
  1570 * more examples in HOL/MiniML and HOL/Auth;
  1571 
  1572 * more default rewrite rules for quantifiers, union/intersection;
  1573 
  1574 * a new constant `arbitrary == @x.False';
  1575 
  1576 * HOLCF/IOA replaces old HOL/IOA;
  1577 
  1578 * HOLCF changes: derived all rules and arities
  1579   + axiomatic type classes instead of classes
  1580   + typedef instead of faking type definitions
  1581   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1582   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1583   + eliminated the types void, one, tr
  1584   + use unit lift and bool lift (with translations) instead of one and tr
  1585   + eliminated blift from Lift3.thy (use Def instead of blift)
  1586   all eliminated rules are derived as theorems --> no visible changes ;
  1587 
  1588 
  1589 *** ZF ***
  1590 
  1591 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1592 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1593 as ZF_cs addSIs [equalityI];
  1594 
  1595 
  1596 
  1597 New in Isabelle94-7 (November 96)
  1598 ---------------------------------
  1599 
  1600 * allowing negative levels (as offsets) in prlev and choplev;
  1601 
  1602 * super-linear speedup for large simplifications;
  1603 
  1604 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1605 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1606 FAIL); can suppress it using the command Delsimps (ex_simps @
  1607 all_simps); De Morgan laws are also now included, by default;
  1608 
  1609 * improved printing of ==>  :  ~:
  1610 
  1611 * new object-logic "Sequents" adds linear logic, while replacing LK
  1612 and Modal (thanks to Sara Kalvala);
  1613 
  1614 * HOL/Auth: correctness proofs for authentication protocols;
  1615 
  1616 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1617 examples on HOL/Auth);
  1618 
  1619 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1620 the rewriter and classical reasoner simultaneously;
  1621 
  1622 * function uresult no longer returns theorems in "standard" format;
  1623 regain previous version by: val uresult = standard o uresult;
  1624 
  1625 
  1626 
  1627 New in Isabelle94-6
  1628 -------------------
  1629 
  1630 * oracles -- these establish an interface between Isabelle and trusted
  1631 external reasoners, which may deliver results as theorems;
  1632 
  1633 * proof objects (in particular record all uses of oracles);
  1634 
  1635 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1636 
  1637 * "constdefs" section in theory files;
  1638 
  1639 * "primrec" section (HOL) no longer requires names;
  1640 
  1641 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1642 
  1643 
  1644 
  1645 New in Isabelle94-5
  1646 -------------------
  1647 
  1648 * reduced space requirements;
  1649 
  1650 * automatic HTML generation from theories;
  1651 
  1652 * theory files no longer require "..." (quotes) around most types;
  1653 
  1654 * new examples, including two proofs of the Church-Rosser theorem;
  1655 
  1656 * non-curried (1994) version of HOL is no longer distributed;
  1657 
  1658 
  1659 
  1660 New in Isabelle94-4
  1661 -------------------
  1662 
  1663 * greatly reduced space requirements;
  1664 
  1665 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1666 
  1667 * searchable theorem database (see the section "Retrieving theorems" on
  1668 page 8 of the Reference Manual);
  1669 
  1670 * new examples, including Grabczewski's monumental case study of the
  1671 Axiom of Choice;
  1672 
  1673 * The previous version of HOL renamed to Old_HOL;
  1674 
  1675 * The new version of HOL (previously called CHOL) uses a curried syntax
  1676 for functions.  Application looks like f a b instead of f(a,b);
  1677 
  1678 * Mutually recursive inductive definitions finally work in HOL;
  1679 
  1680 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1681 translates to the operator "split";
  1682 
  1683 
  1684 
  1685 New in Isabelle94-3
  1686 -------------------
  1687 
  1688 * new infix operator, addss, allowing the classical reasoner to
  1689 perform simplification at each step of its search.  Example:
  1690         fast_tac (cs addss ss)
  1691 
  1692 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1693 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1694 look like (a,b) instead of <a,b>;
  1695 
  1696 * PLEASE NOTE: CHOL will eventually replace HOL!
  1697 
  1698 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1699 It translates to the operator "split".  A new theory of integers is available;
  1700 
  1701 * In ZF, integer numerals now denote two's-complement binary integers.
  1702 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1703 
  1704 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1705 of the Axiom of Choice;
  1706 
  1707 
  1708 
  1709 New in Isabelle94-2
  1710 -------------------
  1711 
  1712 * Significantly faster resolution;
  1713 
  1714 * the different sections in a .thy file can now be mixed and repeated
  1715 freely;
  1716 
  1717 * Database of theorems for FOL, HOL and ZF.  New
  1718 commands including qed, qed_goal and bind_thm store theorems in the database.
  1719 
  1720 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1721 a given theory (thms_of), or find out what theory a theorem was proved in
  1722 (theory_of_thm);
  1723 
  1724 * Bugs fixed in the inductive definition and datatype packages;
  1725 
  1726 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1727 and HOL_dup_cs obsolete;
  1728 
  1729 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1730 have been removed;
  1731 
  1732 * Simpler definition of function space in ZF;
  1733 
  1734 * new results about cardinal and ordinal arithmetic in ZF;
  1735 
  1736 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1737 types;
  1738 
  1739 
  1740 $Id$