NEWS
author wenzelm
Sat Jan 20 00:01:40 2001 +0100 (2001-01-20)
changeset 10944 710ddb9e8b5e
parent 10915 6b66a8a530ce
child 10966 8f2c27041a8e
permissions -rw-r--r--
*** empty log message ***
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 *** Overview of INCOMPATIBILITIES ***
     6 
     7 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
     8 operation;
     9 
    10 * HOL: induct renamed to lfp_induct;
    11 
    12 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    13 
    14 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    15 relation); infix "^^" has been renamed "``"; infix "``" has been
    16 renamed "`"; "univalent" has been renamed "single_valued";
    17 
    18 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    19 
    20 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    21 
    22 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    23 consequence, it is no longer monotonic wrt. the local goal context
    24 (which is now passed through the inductive cases);
    25 
    26 
    27 *** Document preparation ***
    28 
    29 * improved isabelle style files; more abstract symbol implementation
    30 (should now use \isamath{...} and \isatext{...} in custom symbol
    31 definitions);
    32 
    33 * \isabellestyle{NAME} selects version of Isabelle output (currently
    34 available: are "it" for near math-mode best-style output, "sl" for
    35 slanted text style, and "tt" for plain type-writer; if no
    36 \isabellestyle command is given, output is according to slanted
    37 type-writer);
    38 
    39 * support sub/super scripts (for single symbols only), input syntax is
    40 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    41 
    42 * some more standard symbols; see Appendix A of the system manual for
    43 the complete list;
    44 
    45 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    46 state; Note that presentation of goal states does not conform to
    47 actual human-readable proof documents.  Please do not include goal
    48 states into document output unless you really know what you are doing!
    49 
    50 * isatool unsymbolize tunes sources for plain ASCII communication;
    51 
    52 
    53 *** Isar ***
    54 
    55 * Pure: Isar now suffers initial goal statements to contain unbound
    56 schematic variables (this does not conform to actual readable proof
    57 documents, due to unpredictable outcome and non-compositional proof
    58 checking); users who know what they are doing may use schematic goals
    59 for Prolog-style synthesis of proven results;
    60 
    61 * Pure: assumption method (an implicit finishing) now handles actual
    62 rules as well;
    63 
    64 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    65 initial goal, declare "that" only as Pure intro (only for single
    66 steps); the "that" rule assumption may now be involved in implicit
    67 finishing, thus ".." becomes a feasible for trivial obtains;
    68 
    69 * Pure: default proof step now includes 'intro_classes'; thus trivial
    70 instance proofs may be performed by "..";
    71 
    72 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    73 statements as well;
    74 
    75 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    76 rule (as well as the assumption rule);
    77 
    78 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    79 lemmas, using the graph browser tool;
    80 
    81 * Pure: predict failure of "show" in interactive mode;
    82 
    83 * HOL: improved method 'induct' --- now handles non-atomic goals
    84 (potential INCOMPATIBILITY); tuned error handling;
    85 
    86 * HOL: cases and induct rules now provide explicit hints about the
    87 number of facts to be consumed (0 for "type" and 1 for "set" rules);
    88 any remaining facts are inserted into the goal verbatim;
    89 
    90 * HOL: local contexts (aka cases) may now contain term bindings as
    91 well; the 'cases' and 'induct' methods new provide a ?case binding for
    92 the result to be shown in each case;
    93 
    94 * HOL: added 'recdef_tc' command;
    95 
    96 
    97 *** HOL ***
    98 
    99 * HOL/Library: a collection of generic theories to be used together
   100 with main HOL; the theory loader path already includes this directory
   101 by default; the following existing theories have been moved here:
   102 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   103 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   104 
   105 * HOL basics: added overloaded operations "inverse" and "divide"
   106 (infix "/"), syntax for generic "abs" operation, generic summation
   107 operator;
   108 
   109 * HOL/typedef: simplified package, provide more useful rules (see also
   110 HOL/subset.thy);
   111 
   112 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   113 now expressed as a proper nested rule (old-style tactic scripts may
   114 require atomize_strip_tac to cope with non-atomic premises);
   115 
   116 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   117 to "split_conv" (old name still available for compatibility);
   118 
   119 * HOL: improved concrete syntax for strings (e.g. allows translation
   120 rules with string literals);
   121 
   122 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   123 and Fleuriot's mechanization of analysis;
   124 
   125 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   126 
   127 
   128 *** CTT ***
   129 
   130 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   131 "lam" is displayed as TWO lambda-symbols
   132 
   133 * CTT: theory Main now available, containing everything (that is, Bool
   134 and Arith);
   135 
   136 
   137 *** General ***
   138 
   139 * print modes "brackets" and "no_brackets" control output of nested =>
   140 (types) and ==> (props); the default behaviour is "brackets";
   141 
   142 * system: support Poly/ML 4.0 (current beta versions);
   143 
   144 * Pure: the Simplifier has been implemented properly as a derived rule
   145 outside of the actual kernel (at last!); the overall performance
   146 penalty in practical applications is about 50%, while reliability of
   147 the Isabelle inference kernel has been greatly improved;
   148 
   149 * Provers: fast_tac (and friends) now handle actual object-logic rules
   150 as assumptions as well;
   151 
   152 
   153 
   154 New in Isabelle99-1 (October 2000)
   155 ----------------------------------
   156 
   157 *** Overview of INCOMPATIBILITIES ***
   158 
   159 * HOL: simplification of natural numbers is much changed; to partly
   160 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   161 issue the following ML commands:
   162 
   163   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   164   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   165 
   166 * HOL: simplification no longer dives into case-expressions; this is
   167 controlled by "t.weak_case_cong" for each datatype t;
   168 
   169 * HOL: nat_less_induct renamed to less_induct;
   170 
   171 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   172 fixsome to patch .thy and .ML sources automatically;
   173 
   174   select_equality  -> some_equality
   175   select_eq_Ex     -> some_eq_ex
   176   selectI2EX       -> someI2_ex
   177   selectI2         -> someI2
   178   selectI          -> someI
   179   select1_equality -> some1_equality
   180   Eps_sym_eq       -> some_sym_eq_trivial
   181   Eps_eq           -> some_eq_trivial
   182 
   183 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   184 
   185 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   186 instead);
   187 
   188 * HOL: the recursion equations generated by 'recdef' are now called
   189 f.simps instead of f.rules;
   190 
   191 * HOL: qed_spec_mp now also handles bounded ALL as well;
   192 
   193 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   194 sometimes be needed;
   195 
   196 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   197 
   198 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   199 
   200 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   201 product is now "<*>" instead of "Times"; the lexicographic product is
   202 now "<*lex*>" instead of "**";
   203 
   204 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   205 of main HOL, but was unused); better use HOL's datatype package;
   206 
   207 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   208 the old syntax may be recovered as follows:
   209 
   210   syntax (symbols)
   211     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   212       (infixl "\\<oplus>" 100)
   213 
   214 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   215 
   216 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   217 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   218 internally;
   219 
   220 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   221 changed from A/r to A//r;
   222 
   223 * ZF: new treatment of arithmetic (nat & int) may break some old
   224 proofs;
   225 
   226 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   227 rulify -> rule_format, elimify -> elim_format, ...);
   228 
   229 * Isar/Provers: intro/elim/dest attributes changed; renamed
   230 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   231 should have to change intro!! to intro? only); replaced "delrule" by
   232 "rule del";
   233 
   234 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   235 
   236 * Provers: strengthened force_tac by using new first_best_tac;
   237 
   238 * LaTeX document preparation: several changes of isabelle.sty (see
   239 lib/texinputs);
   240 
   241 
   242 *** Document preparation ***
   243 
   244 * formal comments (text blocks etc.) in new-style theories may now
   245 contain antiquotations of thm/prop/term/typ/text to be presented
   246 according to latex print mode; concrete syntax is like this:
   247 @{term[show_types] "f(x) = a + x"};
   248 
   249 * isatool mkdir provides easy setup of Isabelle session directories,
   250 including proper document sources;
   251 
   252 * generated LaTeX sources are now deleted after successful run
   253 (isatool document -c); may retain a copy somewhere else via -D option
   254 of isatool usedir;
   255 
   256 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   257 style files, achieving self-contained LaTeX sources and simplifying
   258 LaTeX debugging;
   259 
   260 * old-style theories now produce (crude) LaTeX output as well;
   261 
   262 * browser info session directories are now self-contained (may be put
   263 on WWW server seperately); improved graphs of nested sessions; removed
   264 graph for 'all sessions';
   265 
   266 * several improvements in isabelle style files; \isabellestyle{it}
   267 produces fake math mode output; \isamarkupheader is now \section by
   268 default; see lib/texinputs/isabelle.sty etc.;
   269 
   270 
   271 *** Isar ***
   272 
   273 * Isar/Pure: local results and corresponding term bindings are now
   274 subject to Hindley-Milner polymorphism (similar to ML); this
   275 accommodates incremental type-inference very nicely;
   276 
   277 * Isar/Pure: new derived language element 'obtain' supports
   278 generalized existence reasoning;
   279 
   280 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   281 support accumulation of results, without applying any rules yet;
   282 useful to collect intermediate results without explicit name
   283 references, and for use with transitivity rules with more than 2
   284 premises;
   285 
   286 * Isar/Pure: scalable support for case-analysis type proofs: new
   287 'case' language element refers to local contexts symbolically, as
   288 produced by certain proof methods; internally, case names are attached
   289 to theorems as "tags";
   290 
   291 * Isar/Pure: theory command 'hide' removes declarations from
   292 class/type/const name spaces;
   293 
   294 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   295 indicate potential overloading;
   296 
   297 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   298 
   299 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   300 "{a,b,c}" instead of {a,b,c};
   301 
   302 * Isar/Pure now provides its own version of intro/elim/dest
   303 attributes; useful for building new logics, but beware of confusion
   304 with the version in Provers/classical;
   305 
   306 * Isar/Pure: the local context of (non-atomic) goals is provided via
   307 case name 'antecedent';
   308 
   309 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   310 to the current context is now done automatically);
   311 
   312 * Isar/Pure: theory command 'method_setup' provides a simple interface
   313 for definining proof methods in ML;
   314 
   315 * Isar/Provers: intro/elim/dest attributes changed; renamed
   316 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   317 most cases, one should have to change intro!! to intro? only);
   318 replaced "delrule" by "rule del";
   319 
   320 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   321 'symmetric' attribute (the latter supercedes [RS sym]);
   322 
   323 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   324 method modifier); 'simp' method: 'only:' modifier removes loopers as
   325 well (including splits);
   326 
   327 * Isar/Provers: Simplifier and Classical methods now support all kind
   328 of modifiers used in the past, including 'cong', 'iff', etc.
   329 
   330 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   331 of Simplifier and Classical reasoner);
   332 
   333 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   334 now support named cases; major packages (inductive, datatype, primrec,
   335 recdef) support case names and properly name parameters;
   336 
   337 * Isar/HOL: new transitivity rules for substitution in inequalities --
   338 monotonicity conditions are extracted to be proven at end of
   339 calculations;
   340 
   341 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   342 method anyway;
   343 
   344 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   345 split_if split_if_asm; datatype package provides theorems foo.splits =
   346 foo.split foo.split_asm for each datatype;
   347 
   348 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   349 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   350 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   351 use "(cases (simplified))" method in proper proof texts);
   352 
   353 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   354 
   355 * Isar: names of theorems etc. may be natural numbers as well;
   356 
   357 * Isar: 'pr' command: optional arguments for goals_limit and
   358 ProofContext.prems_limit; no longer prints theory contexts, but only
   359 proof states;
   360 
   361 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   362 additional print modes to be specified; e.g. "pr(latex)" will print
   363 proof state according to the Isabelle LaTeX style;
   364 
   365 * Isar: improved support for emulating tactic scripts, including proof
   366 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   367 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   368 (for HOL datatypes);
   369 
   370 * Isar: simplified (more robust) goal selection of proof methods: 1st
   371 goal, all goals, or explicit goal specifier (tactic emulation); thus
   372 'proof method scripts' have to be in depth-first order;
   373 
   374 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   375 
   376 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   377 should instead use individual commands for printing items
   378 (print_commands, print_methods etc.);
   379 
   380 * Isar: added 'nothing' --- the empty list of theorems;
   381 
   382 
   383 *** HOL ***
   384 
   385 * HOL/MicroJava: formalization of a fragment of Java, together with a
   386 corresponding virtual machine and a specification of its bytecode
   387 verifier and a lightweight bytecode verifier, including proofs of
   388 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   389 Cornelia Pusch (see also the homepage of project Bali at
   390 http://isabelle.in.tum.de/Bali/);
   391 
   392 * HOL/Algebra: new theory of rings and univariate polynomials, by
   393 Clemens Ballarin;
   394 
   395 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   396 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   397 Rasmussen;
   398 
   399 * HOL/Lattice: fundamental concepts of lattice theory and order
   400 structures, including duals, properties of bounds versus algebraic
   401 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   402 Theorem for complete lattices etc.; may also serve as a demonstration
   403 for abstract algebraic reasoning using axiomatic type classes, and
   404 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   405 
   406 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   407 von Oheimb;
   408 
   409 * HOL/IMPP: extension of IMP with local variables and mutually
   410 recursive procedures, by David von Oheimb;
   411 
   412 * HOL/Lambda: converted into new-style theory and document;
   413 
   414 * HOL/ex/Multiquote: example of multiple nested quotations and
   415 anti-quotations -- basically a generalized version of de-Bruijn
   416 representation; very useful in avoiding lifting of operations;
   417 
   418 * HOL/record: added general record equality rule to simpset; fixed
   419 select-update simplification procedure to handle extended records as
   420 well; admit "r" as field name;
   421 
   422 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   423 other numeric types and also as the identity of groups, rings, etc.;
   424 
   425 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   426 Types nat and int belong to this axclass;
   427 
   428 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   429    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   430    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   431   two terms #m*u and #n*u are replaced by #(m+n)*u
   432     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   433   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   434     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   435 
   436 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   437 powerful prover for predicate logic but knows nothing of clasets; see
   438 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   439 
   440 * HOL: new version of "case_tac" subsumes both boolean case split and
   441 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   442 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   443 
   444 * HOL: simplification no longer dives into case-expressions: only the
   445 selector expression is simplified, but not the remaining arms; to
   446 enable full simplification of case-expressions for datatype t, you may
   447 remove t.weak_case_cong from the simpset, either globally (Delcongs
   448 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   449 
   450 * HOL/recdef: the recursion equations generated by 'recdef' for
   451 function 'f' are now called f.simps instead of f.rules; if all
   452 termination conditions are proved automatically, these simplification
   453 rules are added to the simpset, as in primrec; rules may be named
   454 individually as well, resulting in a separate list of theorems for
   455 each equation;
   456 
   457 * HOL/While is a new theory that provides a while-combinator. It
   458 permits the definition of tail-recursive functions without the
   459 provision of a termination measure. The latter is necessary once the
   460 invariant proof rule for while is applied.
   461 
   462 * HOL: new (overloaded) notation for the set of elements below/above
   463 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   464 
   465 * HOL: theorems impI, allI, ballI bound as "strip";
   466 
   467 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   468 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   469 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   470 
   471 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   472 
   473 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   474 main HOL, but was unused);
   475 
   476 * HOL: fewer consts declared as global (e.g. have to refer to
   477 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   478 
   479 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   480 in case of overlap with user translations (e.g. judgements over
   481 tuples); (note that the underlying logical represenation is still
   482 bogus);
   483 
   484 
   485 *** ZF ***
   486 
   487 * ZF: simplification automatically cancels common terms in arithmetic
   488 expressions over nat and int;
   489 
   490 * ZF: new treatment of nat to minimize type-checking: all operators
   491 coerce their operands to a natural number using the function natify,
   492 making the algebraic laws unconditional;
   493 
   494 * ZF: as above, for int: operators coerce their operands to an integer
   495 using the function intify;
   496 
   497 * ZF: the integer library now contains many of the usual laws for the
   498 orderings, including $<=, and monotonicity laws for $+ and $*;
   499 
   500 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   501 simplification;
   502 
   503 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   504 to the simplifier and classical reasoner simultaneously;
   505 
   506 
   507 *** General ***
   508 
   509 * Provers: blast_tac now handles actual object-logic rules as
   510 assumptions; note that auto_tac uses blast_tac internally as well;
   511 
   512 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   513 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   514 
   515 * Provers: delrules now handles destruct rules as well (no longer need
   516 explicit make_elim);
   517 
   518 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   519   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   520 use instead the strong form,
   521   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   522 in HOL, FOL and ZF the function cla_make_elim will create such rules
   523 from destruct-rules;
   524 
   525 * Provers: Simplifier.easy_setup provides a fast path to basic
   526 Simplifier setup for new object-logics;
   527 
   528 * Pure: AST translation rules no longer require constant head on LHS;
   529 
   530 * Pure: improved name spaces: ambiguous output is qualified; support
   531 for hiding of names;
   532 
   533 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   534 XSYMBOL_HOME; no longer need to do manual configuration in most
   535 situations;
   536 
   537 * system: compression of ML heaps images may now be controlled via -c
   538 option of isabelle and isatool usedir (currently only observed by
   539 Poly/ML);
   540 
   541 * system: isatool installfonts may handle X-Symbol fonts as well (very
   542 useful for remote X11);
   543 
   544 * system: provide TAGS file for Isabelle sources;
   545 
   546 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   547 order;
   548 
   549 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   550 timing flag supersedes proof_timing and Toplevel.trace;
   551 
   552 * ML: new combinators |>> and |>>> for incremental transformations
   553 with secondary results (e.g. certain theory extensions):
   554 
   555 * ML: PureThy.add_defs gets additional argument to indicate potential
   556 overloading (usually false);
   557 
   558 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   559 results;
   560 
   561 
   562 
   563 New in Isabelle99 (October 1999)
   564 --------------------------------
   565 
   566 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   567 
   568 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   569 are no longer simplified.  (This allows the simplifier to unfold recursive
   570 functional programs.)  To restore the old behaviour, declare
   571 
   572     Delcongs [if_weak_cong];
   573 
   574 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   575 complement;
   576 
   577 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   578 
   579 * HOL/datatype: mutual_induct_tac no longer exists --
   580   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   581 
   582 * HOL/typedef: fixed type inference for representing set; type
   583 arguments now have to occur explicitly on the rhs as type constraints;
   584 
   585 * ZF: The con_defs part of an inductive definition may no longer refer
   586 to constants declared in the same theory;
   587 
   588 * HOL, ZF: the function mk_cases, generated by the inductive
   589 definition package, has lost an argument.  To simplify its result, it
   590 uses the default simpset instead of a supplied list of theorems.
   591 
   592 * HOL/List: the constructors of type list are now Nil and Cons;
   593 
   594 * Simplifier: the type of the infix ML functions
   595         setSSolver addSSolver setSolver addSolver
   596 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   597 for packaging solvers. A solver is created via
   598         mk_solver: string -> (thm list -> int -> tactic) -> solver
   599 where the string argument is only a comment.
   600 
   601 
   602 *** Proof tools ***
   603 
   604 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   605 decision procedure for linear arithmetic. Currently it is used for
   606 types `nat', `int', and `real' in HOL (see below); it can, should and
   607 will be instantiated for other types and logics as well.
   608 
   609 * The simplifier now accepts rewrite rules with flexible heads, eg
   610      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   611   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   612   matching.
   613 
   614 
   615 *** General ***
   616 
   617 * New Isabelle/Isar subsystem provides an alternative to traditional
   618 tactical theorem proving; together with the ProofGeneral/isar user
   619 interface it offers an interactive environment for developing human
   620 readable proof documents (Isar == Intelligible semi-automated
   621 reasoning); for further information see isatool doc isar-ref,
   622 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   623 
   624 * improved and simplified presentation of theories: better HTML markup
   625 (including colors), graph views in several sizes; isatool usedir now
   626 provides a proper interface for user theories (via -P option); actual
   627 document preparation based on (PDF)LaTeX is available as well (for
   628 new-style theories only); see isatool doc system for more information;
   629 
   630 * native support for Proof General, both for classic Isabelle and
   631 Isabelle/Isar;
   632 
   633 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   634 using the graph browser tool;
   635 
   636 * Isabelle manuals now also available as PDF;
   637 
   638 * theory loader rewritten from scratch (may not be fully
   639 bug-compatible); old loadpath variable has been replaced by show_path,
   640 add_path, del_path, reset_path functions; new operations such as
   641 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   642 isatool doc ref);
   643 
   644 * improved isatool install: option -k creates KDE application icon,
   645 option -p DIR installs standalone binaries;
   646 
   647 * added ML_PLATFORM setting (useful for cross-platform installations);
   648 more robust handling of platform specific ML images for SML/NJ;
   649 
   650 * the settings environment is now statically scoped, i.e. it is never
   651 created again in sub-processes invoked from isabelle, isatool, or
   652 Isabelle;
   653 
   654 * path element specification '~~' refers to '$ISABELLE_HOME';
   655 
   656 * in locales, the "assumes" and "defines" parts may be omitted if
   657 empty;
   658 
   659 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   660 long arrows);
   661 
   662 * new print_mode "HTML";
   663 
   664 * new flag show_tags controls display of tags of theorems (which are
   665 basically just comments that may be attached by some tools);
   666 
   667 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   668 mode and goal output format:
   669 
   670 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   671 244c244
   672 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   673 ---
   674 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   675 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   676 181c181
   677 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   678 ---
   679 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   680 
   681 * function bind_thms stores lists of theorems (cf. bind_thm);
   682 
   683 * new shorthand tactics ftac, eatac, datac, fatac;
   684 
   685 * qed (and friends) now accept "" as result name; in that case the
   686 theorem is not stored, but proper checks and presentation of the
   687 result still apply;
   688 
   689 * theorem database now also indexes constants "Trueprop", "all",
   690 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   691 
   692 
   693 *** HOL ***
   694 
   695 ** HOL arithmetic **
   696 
   697 * There are now decision procedures for linear arithmetic over nat and
   698 int:
   699 
   700 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   701 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   702 are treated as atomic; subformulae not involving type `nat' or `int'
   703 are ignored; quantified subformulae are ignored unless they are
   704 positive universal or negative existential. The tactic has to be
   705 invoked by hand and can be a little bit slow. In particular, the
   706 running time is exponential in the number of occurrences of `min' and
   707 `max', and `-' on `nat'.
   708 
   709 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   710 (negated) (in)equalities among the premises and the conclusion into
   711 account (i.e. no compound formulae) and does not know about `min' and
   712 `max', and `-' on `nat'. It is fast and is used automatically by the
   713 simplifier.
   714 
   715 NB: At the moment, these decision procedures do not cope with mixed
   716 nat/int formulae where the two parts interact, such as `m < n ==>
   717 int(m) < int(n)'.
   718 
   719 * HOL/Numeral provides a generic theory of numerals (encoded
   720 efficiently as bit strings); setup for types nat/int/real is in place;
   721 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   722 int, existing theories and proof scripts may require a few additional
   723 type constraints;
   724 
   725 * integer division and remainder can now be performed on constant
   726 arguments;
   727 
   728 * many properties of integer multiplication, division and remainder
   729 are now available;
   730 
   731 * An interface to the Stanford Validity Checker (SVC) is available through the
   732 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   733 are proved automatically.  SVC must be installed separately, and its results
   734 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   735 invocation of the underlying oracle).  For SVC see
   736   http://verify.stanford.edu/SVC
   737 
   738 * IsaMakefile: the HOL-Real target now builds an actual image;
   739 
   740 
   741 ** HOL misc **
   742 
   743 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   744 (in Isabelle/Isar) -- by Gertrud Bauer;
   745 
   746 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   747 analysis for assembly languages with subtypes;
   748 
   749 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   750 -- avoids syntactic ambiguities and treats state, transition, and
   751 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   752 changed syntax and (many) tactics;
   753 
   754 * HOL/inductive: Now also handles more general introduction rules such
   755   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   756   theorems are now maintained within the theory (maintained via the
   757   "mono" attribute);
   758 
   759 * HOL/datatype: Now also handles arbitrarily branching datatypes
   760   (using function types) such as
   761 
   762   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   763 
   764 * HOL/record: record_simproc (part of the default simpset) takes care
   765 of selectors applied to updated records; record_split_tac is no longer
   766 part of the default claset; update_defs may now be removed from the
   767 simpset in many cases; COMPATIBILITY: old behavior achieved by
   768 
   769   claset_ref () := claset() addSWrapper record_split_wrapper;
   770   Delsimprocs [record_simproc]
   771 
   772 * HOL/typedef: fixed type inference for representing set; type
   773 arguments now have to occur explicitly on the rhs as type constraints;
   774 
   775 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   776 names rather than an ML expression;
   777 
   778 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   779 supplied later.  Program schemes can be defined, such as
   780     "While B C s = (if B s then While B C (C s) else s)"
   781 where the well-founded relation can be chosen after B and C have been given.
   782 
   783 * HOL/List: the constructors of type list are now Nil and Cons;
   784 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   785 course, ML tools referring to List.list.op # etc. have to be adapted;
   786 
   787 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   788 disabled by default; run isabelle with option -m HOL to get back to
   789 the original Gordon/HOL-style output;
   790 
   791 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   792 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   793 
   794 * HOL basic syntax simplified (more orthogonal): all variants of
   795 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   796 Eps operator is provided as well: "SOME x. P[x]";
   797 
   798 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   799 
   800 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   801 thus available for user theories;
   802 
   803 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   804 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   805 time;
   806 
   807 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   808 several times and then mp;
   809 
   810 
   811 *** LK ***
   812 
   813 * the notation <<...>> is now available as a notation for sequences of
   814 formulas;
   815 
   816 * the simplifier is now installed
   817 
   818 * the axiom system has been generalized (thanks to Soren Heilmann)
   819 
   820 * the classical reasoner now has a default rule database
   821 
   822 
   823 *** ZF ***
   824 
   825 * new primrec section allows primitive recursive functions to be given
   826 directly (as in HOL) over datatypes and the natural numbers;
   827 
   828 * new tactics induct_tac and exhaust_tac for induction (or case
   829 analysis) over datatypes and the natural numbers;
   830 
   831 * the datatype declaration of type T now defines the recursor T_rec;
   832 
   833 * simplification automatically does freeness reasoning for datatype
   834 constructors;
   835 
   836 * automatic type-inference, with AddTCs command to insert new
   837 type-checking rules;
   838 
   839 * datatype introduction rules are now added as Safe Introduction rules
   840 to the claset;
   841 
   842 * the syntax "if P then x else y" is now available in addition to
   843 if(P,x,y);
   844 
   845 
   846 *** Internal programming interfaces ***
   847 
   848 * tuned simplifier trace output; new flag debug_simp;
   849 
   850 * structures Vartab / Termtab (instances of TableFun) offer efficient
   851 tables indexed by indexname_ord / term_ord (compatible with aconv);
   852 
   853 * AxClass.axclass_tac lost the theory argument;
   854 
   855 * tuned current_goals_markers semantics: begin / end goal avoids
   856 printing empty lines;
   857 
   858 * removed prs and prs_fn hook, which was broken because it did not
   859 include \n in its semantics, forcing writeln to add one
   860 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   861 string -> unit if you really want to output text without newline;
   862 
   863 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   864 plain output, interface builders may have to enable 'isabelle_font'
   865 mode to get Isabelle font glyphs as before;
   866 
   867 * refined token_translation interface; INCOMPATIBILITY: output length
   868 now of type real instead of int;
   869 
   870 * theory loader actions may be traced via new ThyInfo.add_hook
   871 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   872 your own database of information attached to *whole* theories -- as
   873 opposed to intra-theory data slots offered via TheoryDataFun;
   874 
   875 * proper handling of dangling sort hypotheses (at last!);
   876 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   877 extra sort hypotheses that can be witnessed from the type signature;
   878 the force_strip_shyps flag is gone, any remaining shyps are simply
   879 left in the theorem (with a warning issued by strip_shyps_warning);
   880 
   881 
   882 
   883 New in Isabelle98-1 (October 1998)
   884 ----------------------------------
   885 
   886 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   887 
   888 * several changes of automated proof tools;
   889 
   890 * HOL: major changes to the inductive and datatype packages, including
   891 some minor incompatibilities of theory syntax;
   892 
   893 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   894 called `inj_on';
   895 
   896 * HOL: removed duplicate thms in Arith:
   897   less_imp_add_less  should be replaced by  trans_less_add1
   898   le_imp_add_le      should be replaced by  trans_le_add1
   899 
   900 * HOL: unary minus is now overloaded (new type constraints may be
   901 required);
   902 
   903 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   904 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   905 now taken as an integer constant.
   906 
   907 * Pure: ML function 'theory_of' renamed to 'theory';
   908 
   909 
   910 *** Proof tools ***
   911 
   912 * Simplifier:
   913   1. Asm_full_simp_tac is now more aggressive.
   914      1. It will sometimes reorient premises if that increases their power to
   915         simplify.
   916      2. It does no longer proceed strictly from left to right but may also
   917         rotate premises to achieve further simplification.
   918      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   919      old Asm_full_simp_tac in that it does not rotate premises.
   920   2. The simplifier now knows a little bit about nat-arithmetic.
   921 
   922 * Classical reasoner: wrapper mechanism for the classical reasoner now
   923 allows for selected deletion of wrappers, by introduction of names for
   924 wrapper functionals.  This implies that addbefore, addSbefore,
   925 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   926 and that adding two tactics with the same name overwrites the first
   927 one (emitting a warning).
   928   type wrapper = (int -> tactic) -> (int -> tactic)
   929   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   930   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   931   delWrapper, delSWrapper: claset *  string            -> claset
   932   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   933 
   934 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   935 semantics; addbefore now affects only the unsafe part of step_tac
   936 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   937 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   938 by Force_tac;
   939 
   940 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   941 compWrapper; added safe wrapper (and access functions for it);
   942 
   943 * HOL/split_all_tac is now much faster and fails if there is nothing
   944 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   945 and the names of the automatically generated variables have changed.
   946 split_all_tac has moved within claset() from unsafe wrappers to safe
   947 wrappers, which means that !!-bound variables are split much more
   948 aggressively, and safe_tac and clarify_tac now split such variables.
   949 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   950 Note: the same holds for record_split_tac, which does the job of
   951 split_all_tac for record fields.
   952 
   953 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   954 permanently to the default simpset using Addsplits just like
   955 Addsimps. They can be removed via Delsplits just like
   956 Delsimps. Lower-case versions are also available.
   957 
   958 * HOL/Simplifier: The rule split_if is now part of the default
   959 simpset. This means that the simplifier will eliminate all occurrences
   960 of if-then-else in the conclusion of a goal. To prevent this, you can
   961 either remove split_if completely from the default simpset by
   962 `Delsplits [split_if]' or remove it in a specific call of the
   963 simplifier using `... delsplits [split_if]'.  You can also add/delete
   964 other case splitting rules to/from the default simpset: every datatype
   965 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   966 t is the name of the datatype).
   967 
   968 * Classical reasoner / Simplifier combination: new force_tac (and
   969 derivatives Force_tac, force) combines rewriting and classical
   970 reasoning (and whatever other tools) similarly to auto_tac, but is
   971 aimed to solve the given subgoal completely.
   972 
   973 
   974 *** General ***
   975 
   976 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   977 and `goalw': the theory is no longer needed as an explicit argument -
   978 the current theory context is used; assumptions are no longer returned
   979 at the ML-level unless one of them starts with ==> or !!; it is
   980 recommended to convert to these new commands using isatool fixgoal
   981 (backup your sources first!);
   982 
   983 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   984 the current theory context, and 'theory' to lookup stored theories;
   985 
   986 * new theory section 'locale' for declaring constants, assumptions and
   987 definitions that have local scope;
   988 
   989 * new theory section 'nonterminals' for purely syntactic types;
   990 
   991 * new theory section 'setup' for generic ML setup functions
   992 (e.g. package initialization);
   993 
   994 * the distribution now includes Isabelle icons: see
   995 lib/logo/isabelle-{small,tiny}.xpm;
   996 
   997 * isatool install - install binaries with absolute references to
   998 ISABELLE_HOME/bin;
   999 
  1000 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1001 
  1002 * print mode 'emacs' reserved for Isamode;
  1003 
  1004 * support multiple print (ast) translations per constant name;
  1005 
  1006 * theorems involving oracles are now printed with a suffixed [!];
  1007 
  1008 
  1009 *** HOL ***
  1010 
  1011 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1012 
  1013 * HOL/inductive package reorganized and improved: now supports mutual
  1014 definitions such as
  1015 
  1016   inductive EVEN ODD
  1017     intrs
  1018       null "0 : EVEN"
  1019       oddI "n : EVEN ==> Suc n : ODD"
  1020       evenI "n : ODD ==> Suc n : EVEN"
  1021 
  1022 new theorem list "elims" contains an elimination rule for each of the
  1023 recursive sets; inductive definitions now handle disjunctive premises
  1024 correctly (also ZF);
  1025 
  1026 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1027 "mutual_induct" no longer exists - the induction rule is always
  1028 contained in "induct";
  1029 
  1030 
  1031 * HOL/datatype package re-implemented and greatly improved: now
  1032 supports mutually recursive datatypes such as
  1033 
  1034   datatype
  1035     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1036             | SUM ('a aexp) ('a aexp)
  1037             | DIFF ('a aexp) ('a aexp)
  1038             | NUM 'a
  1039   and
  1040     'a bexp = LESS ('a aexp) ('a aexp)
  1041             | AND ('a bexp) ('a bexp)
  1042             | OR ('a bexp) ('a bexp)
  1043 
  1044 as well as indirectly recursive datatypes such as
  1045 
  1046   datatype
  1047     ('a, 'b) term = Var 'a
  1048                   | App 'b ((('a, 'b) term) list)
  1049 
  1050 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1051 induction on mutually / indirectly recursive datatypes.
  1052 
  1053 Primrec equations are now stored in theory and can be accessed via
  1054 <function_name>.simps.
  1055 
  1056 INCOMPATIBILITIES:
  1057 
  1058   - Theories using datatypes must now have theory Datatype as an
  1059     ancestor.
  1060   - The specific <typename>.induct_tac no longer exists - use the
  1061     generic induct_tac instead.
  1062   - natE has been renamed to nat.exhaust - use exhaust_tac
  1063     instead of res_inst_tac ... natE. Note that the variable
  1064     names in nat.exhaust differ from the names in natE, this
  1065     may cause some "fragile" proofs to fail.
  1066   - The theorems split_<typename>_case and split_<typename>_case_asm
  1067     have been renamed to <typename>.split and <typename>.split_asm.
  1068   - Since default sorts of type variables are now handled correctly,
  1069     some datatype definitions may have to be annotated with explicit
  1070     sort constraints.
  1071   - Primrec definitions no longer require function name and type
  1072     of recursive argument.
  1073 
  1074 Consider using isatool fixdatatype to adapt your theories and proof
  1075 scripts to the new package (backup your sources first!).
  1076 
  1077 
  1078 * HOL/record package: considerably improved implementation; now
  1079 includes concrete syntax for record types, terms, updates; theorems
  1080 for surjective pairing and splitting !!-bound record variables; proof
  1081 support is as follows:
  1082 
  1083   1) standard conversions (selectors or updates applied to record
  1084 constructor terms) are part of the standard simpset;
  1085 
  1086   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1087 made part of standard simpset and claset via addIffs;
  1088 
  1089   3) a tactic for record field splitting (record_split_tac) is part of
  1090 the standard claset (addSWrapper);
  1091 
  1092 To get a better idea about these rules you may retrieve them via
  1093 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1094 the name of your record type.
  1095 
  1096 The split tactic 3) conceptually simplifies by the following rule:
  1097 
  1098   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1099 
  1100 Thus any record variable that is bound by meta-all will automatically
  1101 blow up into some record constructor term, consequently the
  1102 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1103 solve record problems automatically.
  1104 
  1105 
  1106 * reorganized the main HOL image: HOL/Integ and String loaded by
  1107 default; theory Main includes everything;
  1108 
  1109 * automatic simplification of integer sums and comparisons, using cancellation;
  1110 
  1111 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1112 
  1113 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1114 
  1115 * many new identities for unions, intersections, set difference, etc.;
  1116 
  1117 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1118 called split_if, split_split, split_sum_case and split_nat_case (to go
  1119 with add/delsplits);
  1120 
  1121 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1122 (?x::unit) = (); this is made part of the default simpset, which COULD
  1123 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1124 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1125 unit_abs_eta_conv is added in order to counter the effect of
  1126 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1127 %u.f();
  1128 
  1129 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1130 makes more sense);
  1131 
  1132 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1133   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1134   disjointness reasoning but breaking a few old proofs.
  1135 
  1136 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1137 to 'converse' from 'inverse' (for compatibility with ZF and some
  1138 literature);
  1139 
  1140 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1141 the well-founded relation;
  1142 
  1143 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1144     Compl A.  The "Compl" syntax remains available as input syntax for this
  1145     release ONLY.
  1146 
  1147 * HOL/Update: new theory of function updates:
  1148     f(a:=b) == %x. if x=a then b else f x
  1149 may also be iterated as in f(a:=b,c:=d,...);
  1150 
  1151 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1152 
  1153 * HOL/List:
  1154   - new function list_update written xs[i:=v] that updates the i-th
  1155     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1156   - new function `upt' written [i..j(] which generates the list
  1157     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1158     bound write [i..j], which is a shorthand for [i..j+1(].
  1159   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1160 
  1161 * HOL/Arith:
  1162   - removed 'pred' (predecessor) function;
  1163   - generalized some theorems about n-1;
  1164   - many new laws about "div" and "mod";
  1165   - new laws about greatest common divisors (see theory ex/Primes);
  1166 
  1167 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1168 instead of "inverse";
  1169 
  1170 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1171   of the multiset ordering;
  1172 
  1173 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1174   (not included by default);
  1175 
  1176 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1177 
  1178 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1179   programs, i.e. different program variables may have different types.
  1180 
  1181 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1182   [previously, this check worked only if the rewrite rule was unconditional]
  1183   Now rew can involve either definitions or equalities (either == or =).
  1184 
  1185 
  1186 *** ZF ***
  1187 
  1188 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1189   only the theorems proved on ZF.ML;
  1190 
  1191 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1192   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1193   disjointness reasoning but breaking a few old proofs.
  1194 
  1195 * ZF/Update: new theory of function updates
  1196     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1197   may also be iterated as in f(a:=b,c:=d,...);
  1198 
  1199 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  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 * case_tac provided for compatibility with HOL
  1206     (like the old excluded_middle_tac, but with subgoals swapped)
  1207 
  1208 
  1209 *** Internal programming interfaces ***
  1210 
  1211 * Pure: several new basic modules made available for general use, see
  1212 also src/Pure/README;
  1213 
  1214 * improved the theory data mechanism to support encapsulation (data
  1215 kind name replaced by private Object.kind, acting as authorization
  1216 key); new type-safe user interface via functor TheoryDataFun; generic
  1217 print_data function becomes basically useless;
  1218 
  1219 * removed global_names compatibility flag -- all theory declarations
  1220 are qualified by default;
  1221 
  1222 * module Pure/Syntax now offers quote / antiquote translation
  1223 functions (useful for Hoare logic etc. with implicit dependencies);
  1224 see HOL/ex/Antiquote for an example use;
  1225 
  1226 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1227 cterm -> thm;
  1228 
  1229 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1230 subgoal;
  1231 
  1232 * Display.print_goals function moved to Locale.print_goals;
  1233 
  1234 * standard print function for goals supports current_goals_markers
  1235 variable for marking begin of proof, end of proof, start of goal; the
  1236 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1237 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1238 for example;
  1239 
  1240 
  1241 
  1242 New in Isabelle98 (January 1998)
  1243 --------------------------------
  1244 
  1245 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1246 
  1247 * changed lexical syntax of terms / types: dots made part of long
  1248 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1249 
  1250 * simpset (and claset) reference variable replaced by functions
  1251 simpset / simpset_ref;
  1252 
  1253 * no longer supports theory aliases (via merge) and non-trivial
  1254 implicit merge of thms' signatures;
  1255 
  1256 * most internal names of constants changed due to qualified names;
  1257 
  1258 * changed Pure/Sequence interface (see Pure/seq.ML);
  1259 
  1260 
  1261 *** General Changes ***
  1262 
  1263 * hierachically structured name spaces (for consts, types, axms, thms
  1264 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1265 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1266 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1267 long_names for fully qualified output names; NOTE: ML programs
  1268 (special tactics, packages etc.) referring to internal names may have
  1269 to be adapted to cope with fully qualified names; in case of severe
  1270 backward campatibility problems try setting 'global_names' at compile
  1271 time to have enrything declared within a flat name space; one may also
  1272 fine tune name declarations in theories via the 'global' and 'local'
  1273 section;
  1274 
  1275 * reimplemented the implicit simpset and claset using the new anytype
  1276 data filed in signatures; references simpset:simpset ref etc. are
  1277 replaced by functions simpset:unit->simpset and
  1278 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1279 to patch your ML files accordingly;
  1280 
  1281 * HTML output now includes theory graph data for display with Java
  1282 applet or isatool browser; data generated automatically via isatool
  1283 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1284 
  1285 * defs may now be conditional; improved rewrite_goals_tac to handle
  1286 conditional equations;
  1287 
  1288 * defs now admits additional type arguments, using TYPE('a) syntax;
  1289 
  1290 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1291 creates a new theory node; implicit merge of thms' signatures is
  1292 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1293 transfer:theory->thm->thm in (rare) cases;
  1294 
  1295 * improved handling of draft signatures / theories; draft thms (and
  1296 ctyps, cterms) are automatically promoted to real ones;
  1297 
  1298 * slightly changed interfaces for oracles: admit many per theory, named
  1299 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1300 
  1301 * print_goals: optional output of const types (set show_consts and
  1302 show_types);
  1303 
  1304 * improved output of warnings (###) and errors (***);
  1305 
  1306 * subgoal_tac displays a warning if the new subgoal has type variables;
  1307 
  1308 * removed old README and Makefiles;
  1309 
  1310 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1311 
  1312 * removed obsolete init_pps and init_database;
  1313 
  1314 * deleted the obsolete tactical STATE, which was declared by
  1315     fun STATE tacfun st = tacfun st st;
  1316 
  1317 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1318 (which abbreviates $HOME);
  1319 
  1320 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1321 use isatool fixseq to adapt your ML programs (this works for fully
  1322 qualified references to the Sequence structure only!);
  1323 
  1324 * use_thy no longer requires writable current directory; it always
  1325 reloads .ML *and* .thy file, if either one is out of date;
  1326 
  1327 
  1328 *** Classical Reasoner ***
  1329 
  1330 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1331 tactics that use classical reasoning to simplify a subgoal without
  1332 splitting it into several subgoals;
  1333 
  1334 * Safe_tac: like safe_tac but uses the default claset;
  1335 
  1336 
  1337 *** Simplifier ***
  1338 
  1339 * added simplification meta rules:
  1340     (asm_)(full_)simplify: simpset -> thm -> thm;
  1341 
  1342 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1343 logics (again);
  1344 
  1345 * added prems argument to simplification procedures;
  1346 
  1347 * HOL, FOL, ZF: added infix function `addsplits':
  1348   instead of `<simpset> setloop (split_tac <thms>)'
  1349   you can simply write `<simpset> addsplits <thms>'
  1350 
  1351 
  1352 *** Syntax ***
  1353 
  1354 * TYPE('a) syntax for type reflection terms;
  1355 
  1356 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1357 
  1358 * pretty printer: changed order of mixfix annotation preference (again!);
  1359 
  1360 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1361 
  1362 
  1363 *** HOL ***
  1364 
  1365 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1366   with `addloop' of the simplifier to faciliate case splitting in premises.
  1367 
  1368 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1369 
  1370 * HOL/Auth: new protocol proofs including some for the Internet
  1371   protocol TLS;
  1372 
  1373 * HOL/Map: new theory of `maps' a la VDM;
  1374 
  1375 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1376 cancelling out common nat summands from =, <, <= (in)equalities, or
  1377 differences; simplification procedures nat_cancel_factor for
  1378 cancelling common factor from =, <, <= (in)equalities over natural
  1379 sums; nat_cancel contains both kinds of procedures, it is installed by
  1380 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1381 
  1382 * HOL/simplifier: terms of the form
  1383   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1384   are rewritten to
  1385   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1386   and those of the form
  1387   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1388   are rewritten to
  1389   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1390 
  1391 * HOL/datatype
  1392   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1393 
  1394   P(t_case f1 ... fn x) =
  1395      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1396         ...
  1397        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1398      )
  1399 
  1400   and a theorem `split_t_case_asm' of the form
  1401 
  1402   P(t_case f1 ... fn x) =
  1403     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1404         ...
  1405        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1406      )
  1407   which can be added to a simpset via `addsplits'. The existing theorems
  1408   expand_list_case and expand_option_case have been renamed to
  1409   split_list_case and split_option_case.
  1410 
  1411 * HOL/Arithmetic:
  1412   - `pred n' is automatically converted to `n-1'.
  1413     Users are strongly encouraged not to use `pred' any longer,
  1414     because it will disappear altogether at some point.
  1415   - Users are strongly encouraged to write "0 < n" rather than
  1416     "n ~= 0". Theorems and proof tools have been modified towards this
  1417     `standard'.
  1418 
  1419 * HOL/Lists:
  1420   the function "set_of_list" has been renamed "set" (and its theorems too);
  1421   the function "nth" now takes its arguments in the reverse order and
  1422   has acquired the infix notation "!" as in "xs!n".
  1423 
  1424 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1425 
  1426 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1427   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1428 
  1429 * HOL/record: extensible records with schematic structural subtyping
  1430 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1431 still lacks various theorems and concrete record syntax;
  1432 
  1433 
  1434 *** HOLCF ***
  1435 
  1436 * removed "axioms" and "generated by" sections;
  1437 
  1438 * replaced "ops" section by extended "consts" section, which is capable of
  1439   handling the continuous function space "->" directly;
  1440 
  1441 * domain package:
  1442   . proves theorems immediately and stores them in the theory,
  1443   . creates hierachical name space,
  1444   . now uses normal mixfix annotations (instead of cinfix...),
  1445   . minor changes to some names and values (for consistency),
  1446   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1447   . separator between mutual domain defs: changed "," to "and",
  1448   . improved handling of sort constraints;  now they have to
  1449     appear on the left-hand side of the equations only;
  1450 
  1451 * fixed LAM <x,y,zs>.b syntax;
  1452 
  1453 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1454 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1455 
  1456 
  1457 *** FOL and ZF ***
  1458 
  1459 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1460   with `addloop' of the simplifier to faciliate case splitting in premises.
  1461 
  1462 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1463 in HOL, they strip ALL and --> from proved theorems;
  1464 
  1465 
  1466 
  1467 New in Isabelle94-8 (May 1997)
  1468 ------------------------------
  1469 
  1470 *** General Changes ***
  1471 
  1472 * new utilities to build / run / maintain Isabelle etc. (in parts
  1473 still somewhat experimental); old Makefiles etc. still functional;
  1474 
  1475 * new 'Isabelle System Manual';
  1476 
  1477 * INSTALL text, together with ./configure and ./build scripts;
  1478 
  1479 * reimplemented type inference for greater efficiency, better error
  1480 messages and clean internal interface;
  1481 
  1482 * prlim command for dealing with lots of subgoals (an easier way of
  1483 setting goals_limit);
  1484 
  1485 
  1486 *** Syntax ***
  1487 
  1488 * supports alternative (named) syntax tables (parser and pretty
  1489 printer); internal interface is provided by add_modesyntax(_i);
  1490 
  1491 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1492 be used in conjunction with the Isabelle symbol font; uses the
  1493 "symbols" syntax table;
  1494 
  1495 * added token_translation interface (may translate name tokens in
  1496 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1497 the current print_mode); IMPORTANT: user print translation functions
  1498 are responsible for marking newly introduced bounds
  1499 (Syntax.mark_boundT);
  1500 
  1501 * token translations for modes "xterm" and "xterm_color" that display
  1502 names in bold, underline etc. or colors (which requires a color
  1503 version of xterm);
  1504 
  1505 * infixes may now be declared with names independent of their syntax;
  1506 
  1507 * added typed_print_translation (like print_translation, but may
  1508 access type of constant);
  1509 
  1510 
  1511 *** Classical Reasoner ***
  1512 
  1513 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1514 some limitations.  Blast_tac...
  1515   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1516   + ignores elimination rules that don't have the correct format
  1517         (the conclusion MUST be a formula variable)
  1518   + ignores types, which can make HOL proofs fail
  1519   + rules must not require higher-order unification, e.g. apply_type in ZF
  1520     [message "Function Var's argument not a bound variable" relates to this]
  1521   + its proof strategy is more general but can actually be slower
  1522 
  1523 * substitution with equality assumptions no longer permutes other
  1524 assumptions;
  1525 
  1526 * minor changes in semantics of addafter (now called addaltern); renamed
  1527 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1528 (and access functions for it);
  1529 
  1530 * improved combination of classical reasoner and simplifier:
  1531   + functions for handling clasimpsets
  1532   + improvement of addss: now the simplifier is called _after_ the
  1533     safe steps.
  1534   + safe variant of addss called addSss: uses safe simplifications
  1535     _during_ the safe steps. It is more complete as it allows multiple
  1536     instantiations of unknowns (e.g. with slow_tac).
  1537 
  1538 *** Simplifier ***
  1539 
  1540 * added interface for simplification procedures (functions that
  1541 produce *proven* rewrite rules on the fly, depending on current
  1542 redex);
  1543 
  1544 * ordering on terms as parameter (used for ordered rewriting);
  1545 
  1546 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1547 
  1548 * the solver is now split into a safe and an unsafe part.
  1549 This should be invisible for the normal user, except that the
  1550 functions setsolver and addsolver have been renamed to setSolver and
  1551 addSolver; added safe_asm_full_simp_tac;
  1552 
  1553 
  1554 *** HOL ***
  1555 
  1556 * a generic induction tactic `induct_tac' which works for all datatypes and
  1557 also for type `nat';
  1558 
  1559 * a generic case distinction tactic `exhaust_tac' which works for all
  1560 datatypes and also for type `nat';
  1561 
  1562 * each datatype comes with a function `size';
  1563 
  1564 * patterns in case expressions allow tuple patterns as arguments to
  1565 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1566 
  1567 * primrec now also works with type nat;
  1568 
  1569 * recdef: a new declaration form, allows general recursive functions to be
  1570 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1571 
  1572 * the constant for negation has been renamed from "not" to "Not" to
  1573 harmonize with FOL, ZF, LK, etc.;
  1574 
  1575 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1576 infinite lists;
  1577 
  1578 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1579 
  1580 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1581 problems in commutative rings, using axiomatic type classes for + and *;
  1582 
  1583 * more examples in HOL/MiniML and HOL/Auth;
  1584 
  1585 * more default rewrite rules for quantifiers, union/intersection;
  1586 
  1587 * a new constant `arbitrary == @x.False';
  1588 
  1589 * HOLCF/IOA replaces old HOL/IOA;
  1590 
  1591 * HOLCF changes: derived all rules and arities
  1592   + axiomatic type classes instead of classes
  1593   + typedef instead of faking type definitions
  1594   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1595   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1596   + eliminated the types void, one, tr
  1597   + use unit lift and bool lift (with translations) instead of one and tr
  1598   + eliminated blift from Lift3.thy (use Def instead of blift)
  1599   all eliminated rules are derived as theorems --> no visible changes ;
  1600 
  1601 
  1602 *** ZF ***
  1603 
  1604 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1605 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1606 as ZF_cs addSIs [equalityI];
  1607 
  1608 
  1609 
  1610 New in Isabelle94-7 (November 96)
  1611 ---------------------------------
  1612 
  1613 * allowing negative levels (as offsets) in prlev and choplev;
  1614 
  1615 * super-linear speedup for large simplifications;
  1616 
  1617 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1618 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1619 FAIL); can suppress it using the command Delsimps (ex_simps @
  1620 all_simps); De Morgan laws are also now included, by default;
  1621 
  1622 * improved printing of ==>  :  ~:
  1623 
  1624 * new object-logic "Sequents" adds linear logic, while replacing LK
  1625 and Modal (thanks to Sara Kalvala);
  1626 
  1627 * HOL/Auth: correctness proofs for authentication protocols;
  1628 
  1629 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1630 examples on HOL/Auth);
  1631 
  1632 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1633 the rewriter and classical reasoner simultaneously;
  1634 
  1635 * function uresult no longer returns theorems in "standard" format;
  1636 regain previous version by: val uresult = standard o uresult;
  1637 
  1638 
  1639 
  1640 New in Isabelle94-6
  1641 -------------------
  1642 
  1643 * oracles -- these establish an interface between Isabelle and trusted
  1644 external reasoners, which may deliver results as theorems;
  1645 
  1646 * proof objects (in particular record all uses of oracles);
  1647 
  1648 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1649 
  1650 * "constdefs" section in theory files;
  1651 
  1652 * "primrec" section (HOL) no longer requires names;
  1653 
  1654 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1655 
  1656 
  1657 
  1658 New in Isabelle94-5
  1659 -------------------
  1660 
  1661 * reduced space requirements;
  1662 
  1663 * automatic HTML generation from theories;
  1664 
  1665 * theory files no longer require "..." (quotes) around most types;
  1666 
  1667 * new examples, including two proofs of the Church-Rosser theorem;
  1668 
  1669 * non-curried (1994) version of HOL is no longer distributed;
  1670 
  1671 
  1672 
  1673 New in Isabelle94-4
  1674 -------------------
  1675 
  1676 * greatly reduced space requirements;
  1677 
  1678 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1679 
  1680 * searchable theorem database (see the section "Retrieving theorems" on
  1681 page 8 of the Reference Manual);
  1682 
  1683 * new examples, including Grabczewski's monumental case study of the
  1684 Axiom of Choice;
  1685 
  1686 * The previous version of HOL renamed to Old_HOL;
  1687 
  1688 * The new version of HOL (previously called CHOL) uses a curried syntax
  1689 for functions.  Application looks like f a b instead of f(a,b);
  1690 
  1691 * Mutually recursive inductive definitions finally work in HOL;
  1692 
  1693 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1694 translates to the operator "split";
  1695 
  1696 
  1697 
  1698 New in Isabelle94-3
  1699 -------------------
  1700 
  1701 * new infix operator, addss, allowing the classical reasoner to
  1702 perform simplification at each step of its search.  Example:
  1703         fast_tac (cs addss ss)
  1704 
  1705 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1706 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1707 look like (a,b) instead of <a,b>;
  1708 
  1709 * PLEASE NOTE: CHOL will eventually replace HOL!
  1710 
  1711 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1712 It translates to the operator "split".  A new theory of integers is available;
  1713 
  1714 * In ZF, integer numerals now denote two's-complement binary integers.
  1715 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1716 
  1717 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1718 of the Axiom of Choice;
  1719 
  1720 
  1721 
  1722 New in Isabelle94-2
  1723 -------------------
  1724 
  1725 * Significantly faster resolution;
  1726 
  1727 * the different sections in a .thy file can now be mixed and repeated
  1728 freely;
  1729 
  1730 * Database of theorems for FOL, HOL and ZF.  New
  1731 commands including qed, qed_goal and bind_thm store theorems in the database.
  1732 
  1733 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1734 a given theory (thms_of), or find out what theory a theorem was proved in
  1735 (theory_of_thm);
  1736 
  1737 * Bugs fixed in the inductive definition and datatype packages;
  1738 
  1739 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1740 and HOL_dup_cs obsolete;
  1741 
  1742 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1743 have been removed;
  1744 
  1745 * Simpler definition of function space in ZF;
  1746 
  1747 * new results about cardinal and ordinal arithmetic in ZF;
  1748 
  1749 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1750 types;
  1751 
  1752 
  1753 $Id$