NEWS
author wenzelm
Fri Dec 22 18:20:55 2000 +0100 (2000-12-22)
changeset 10726 e12b81140945
parent 10664 da5373fa06de
child 10756 831c864cc56e
permissions -rw-r--r--
tuned;
     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 function;
     9 
    10 * HOL: induct renamed to lfp_induct;
    11 
    12 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    13 
    14 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    15 
    16 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    17 consequence, it is no longer monotonic wrt. the local goal context
    18 (which is now passed through the inductive cases);
    19 
    20 
    21 *** Document preparation ***
    22 
    23 * improved isabelle style files; more abstract symbol implementation
    24 (should now use \isamath{...} and \isatext{...} in custom symbol
    25 definitions);
    26 
    27 * support sub/super scripts (for single symbols only), input syntax is
    28 like this: "A\<^sup>*" or "A\<^sup>\<star>";
    29 
    30 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    31 state; Note that presentation of goal states does not conform to
    32 actual human-readable proof documents.  Please do not include goal
    33 states into document output unless you really know what you are doing!
    34 
    35 
    36 *** Isar ***
    37 
    38 * Pure: Isar now suffers initial goal statements to contain unbound
    39 schematic variables (this does not conform to actual readable proof
    40 documents, due to unpredictable outcome and non-compositional proof
    41 checking); users who know what they are doing may use schematic goals
    42 for Prolog-style synthesis of proven results;
    43 
    44 * Pure: assumption method (an implicit finishing) now handles actual
    45 rules as well;
    46 
    47 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    48 initial goal, declare "that" only as Pure intro (only for single
    49 steps); the "that" rule assumption may now be involved in implicit
    50 finishing, thus ".." becomes a feasible for trivial obtains;
    51 
    52 * Pure: default proof step now includes 'intro_classes'; thus trivial
    53 instance proofs may be performed by "..";
    54 
    55 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    56 statements as well;
    57 
    58 * HOL: improved method 'induct' --- now handles non-atomic goals
    59 (potential INCOMPATIBILITY); tuned error handling;
    60 
    61 * HOL: cases and induct rules now provide explicit hints about the
    62 number of facts to be consumed (0 for "type" and 1 for "set" rules);
    63 any remaining facts are inserted into the goal verbatim;
    64 
    65 
    66 *** HOL ***
    67 
    68 * HOL/Library: a collection of generic theories to be used together
    69 with main HOL; the theory loader path already includes this directory
    70 by default; the following existing theories have been moved here:
    71 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
    72 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
    73 
    74 * HOL basics: added overloaded operations "inverse" and "divide"
    75 (infix "/"), syntax for generic "abs" operation, generic summation
    76 operator;
    77 
    78 * HOL/typedef: simplified package, provide more useful rules (see also
    79 HOL/subset.thy);
    80 
    81 
    82 *** CTT ***
    83 
    84 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
    85 "lam" is displayed as TWO lambda-symbols
    86 
    87 * CTT: theory Main now available, containing everything (that is, Bool
    88 and Arith);
    89 
    90 
    91 *** General ***
    92 
    93 * print modes "brackets" and "no_brackets" control output of nested =>
    94 (types) and ==> (props); the default behaviour is "brackets";
    95 
    96 * system: support Poly/ML 4.0 (current beta versions);
    97 
    98 * Pure: the Simplifier has been implemented properly as a derived rule
    99 outside of the actual kernel (at last!); the overall performance
   100 penalty in practical applications is about 50%, while reliability of
   101 the Isabelle inference kernel has been greatly improved;
   102 
   103 * Provers: fast_tac (and friends) now handle actual object-logic rules
   104 as assumptions as well;
   105 
   106 
   107 
   108 New in Isabelle99-1 (October 2000)
   109 ----------------------------------
   110 
   111 *** Overview of INCOMPATIBILITIES ***
   112 
   113 * HOL: simplification of natural numbers is much changed; to partly
   114 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   115 issue the following ML commands:
   116 
   117   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   118   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   119 
   120 * HOL: simplification no longer dives into case-expressions; this is
   121 controlled by "t.weak_case_cong" for each datatype t;
   122 
   123 * HOL: nat_less_induct renamed to less_induct;
   124 
   125 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   126 fixsome to patch .thy and .ML sources automatically;
   127 
   128   select_equality  -> some_equality
   129   select_eq_Ex     -> some_eq_ex
   130   selectI2EX       -> someI2_ex
   131   selectI2         -> someI2
   132   selectI          -> someI
   133   select1_equality -> some1_equality
   134   Eps_sym_eq       -> some_sym_eq_trivial
   135   Eps_eq           -> some_eq_trivial
   136 
   137 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   138 
   139 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   140 instead);
   141 
   142 * HOL: the recursion equations generated by 'recdef' are now called
   143 f.simps instead of f.rules;
   144 
   145 * HOL: qed_spec_mp now also handles bounded ALL as well;
   146 
   147 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   148 sometimes be needed;
   149 
   150 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   151 
   152 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   153 
   154 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   155 product is now "<*>" instead of "Times"; the lexicographic product is
   156 now "<*lex*>" instead of "**";
   157 
   158 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   159 of main HOL, but was unused); better use HOL's datatype package;
   160 
   161 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   162 the old syntax may be recovered as follows:
   163 
   164   syntax (symbols)
   165     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   166       (infixl "\\<oplus>" 100)
   167 
   168 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   169 
   170 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   171 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   172 internally;
   173 
   174 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   175 changed from A/r to A//r;
   176 
   177 * ZF: new treatment of arithmetic (nat & int) may break some old
   178 proofs;
   179 
   180 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   181 rulify -> rule_format, elimify -> elim_format, ...);
   182 
   183 * Isar/Provers: intro/elim/dest attributes changed; renamed
   184 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   185 should have to change intro!! to intro? only); replaced "delrule" by
   186 "rule del";
   187 
   188 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   189 
   190 * Provers: strengthened force_tac by using new first_best_tac;
   191 
   192 * LaTeX document preparation: several changes of isabelle.sty (see
   193 lib/texinputs);
   194 
   195 
   196 *** Document preparation ***
   197 
   198 * formal comments (text blocks etc.) in new-style theories may now
   199 contain antiquotations of thm/prop/term/typ/text to be presented
   200 according to latex print mode; concrete syntax is like this:
   201 @{term[show_types] "f(x) = a + x"};
   202 
   203 * isatool mkdir provides easy setup of Isabelle session directories,
   204 including proper document sources;
   205 
   206 * generated LaTeX sources are now deleted after successful run
   207 (isatool document -c); may retain a copy somewhere else via -D option
   208 of isatool usedir;
   209 
   210 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   211 style files, achieving self-contained LaTeX sources and simplifying
   212 LaTeX debugging;
   213 
   214 * old-style theories now produce (crude) LaTeX output as well;
   215 
   216 * browser info session directories are now self-contained (may be put
   217 on WWW server seperately); improved graphs of nested sessions; removed
   218 graph for 'all sessions';
   219 
   220 * several improvements in isabelle style files; \isabellestyle{it}
   221 produces fake math mode output; \isamarkupheader is now \section by
   222 default; see lib/texinputs/isabelle.sty etc.;
   223 
   224 
   225 *** Isar ***
   226 
   227 * Isar/Pure: local results and corresponding term bindings are now
   228 subject to Hindley-Milner polymorphism (similar to ML); this
   229 accommodates incremental type-inference very nicely;
   230 
   231 * Isar/Pure: new derived language element 'obtain' supports
   232 generalized existence reasoning;
   233 
   234 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   235 support accumulation of results, without applying any rules yet;
   236 useful to collect intermediate results without explicit name
   237 references, and for use with transitivity rules with more than 2
   238 premises;
   239 
   240 * Isar/Pure: scalable support for case-analysis type proofs: new
   241 'case' language element refers to local contexts symbolically, as
   242 produced by certain proof methods; internally, case names are attached
   243 to theorems as "tags";
   244 
   245 * Isar/Pure: theory command 'hide' removes declarations from
   246 class/type/const name spaces;
   247 
   248 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   249 indicate potential overloading;
   250 
   251 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   252 
   253 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   254 "{a,b,c}" instead of {a,b,c};
   255 
   256 * Isar/Pure now provides its own version of intro/elim/dest
   257 attributes; useful for building new logics, but beware of confusion
   258 with the version in Provers/classical;
   259 
   260 * Isar/Pure: the local context of (non-atomic) goals is provided via
   261 case name 'antecedent';
   262 
   263 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   264 to the current context is now done automatically);
   265 
   266 * Isar/Pure: theory command 'method_setup' provides a simple interface
   267 for definining proof methods in ML;
   268 
   269 * Isar/Provers: intro/elim/dest attributes changed; renamed
   270 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   271 most cases, one should have to change intro!! to intro? only);
   272 replaced "delrule" by "rule del";
   273 
   274 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   275 'symmetric' attribute (the latter supercedes [RS sym]);
   276 
   277 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   278 method modifier); 'simp' method: 'only:' modifier removes loopers as
   279 well (including splits);
   280 
   281 * Isar/Provers: Simplifier and Classical methods now support all kind
   282 of modifiers used in the past, including 'cong', 'iff', etc.
   283 
   284 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   285 of Simplifier and Classical reasoner);
   286 
   287 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   288 now support named cases; major packages (inductive, datatype, primrec,
   289 recdef) support case names and properly name parameters;
   290 
   291 * Isar/HOL: new transitivity rules for substitution in inequalities --
   292 monotonicity conditions are extracted to be proven at end of
   293 calculations;
   294 
   295 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   296 method anyway;
   297 
   298 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   299 split_if split_if_asm; datatype package provides theorems foo.splits =
   300 foo.split foo.split_asm for each datatype;
   301 
   302 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   303 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   304 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   305 use "(cases (simplified))" method in proper proof texts);
   306 
   307 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   308 
   309 * Isar: names of theorems etc. may be natural numbers as well;
   310 
   311 * Isar: 'pr' command: optional arguments for goals_limit and
   312 ProofContext.prems_limit; no longer prints theory contexts, but only
   313 proof states;
   314 
   315 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   316 additional print modes to be specified; e.g. "pr(latex)" will print
   317 proof state according to the Isabelle LaTeX style;
   318 
   319 * Isar: improved support for emulating tactic scripts, including proof
   320 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   321 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   322 (for HOL datatypes);
   323 
   324 * Isar: simplified (more robust) goal selection of proof methods: 1st
   325 goal, all goals, or explicit goal specifier (tactic emulation); thus
   326 'proof method scripts' have to be in depth-first order;
   327 
   328 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   329 
   330 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   331 should instead use individual commands for printing items
   332 (print_commands, print_methods etc.);
   333 
   334 * Isar: added 'nothing' --- the empty list of theorems;
   335 
   336 
   337 *** HOL ***
   338 
   339 * HOL/MicroJava: formalization of a fragment of Java, together with a
   340 corresponding virtual machine and a specification of its bytecode
   341 verifier and a lightweight bytecode verifier, including proofs of
   342 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   343 Cornelia Pusch (see also the homepage of project Bali at
   344 http://isabelle.in.tum.de/Bali/);
   345 
   346 * HOL/Algebra: new theory of rings and univariate polynomials, by
   347 Clemens Ballarin;
   348 
   349 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   350 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   351 Rasmussen;
   352 
   353 * HOL/Lattice: fundamental concepts of lattice theory and order
   354 structures, including duals, properties of bounds versus algebraic
   355 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   356 Theorem for complete lattices etc.; may also serve as a demonstration
   357 for abstract algebraic reasoning using axiomatic type classes, and
   358 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   359 
   360 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   361 von Oheimb;
   362 
   363 * HOL/IMPP: extension of IMP with local variables and mutually
   364 recursive procedures, by David von Oheimb;
   365 
   366 * HOL/Lambda: converted into new-style theory and document;
   367 
   368 * HOL/ex/Multiquote: example of multiple nested quotations and
   369 anti-quotations -- basically a generalized version of de-Bruijn
   370 representation; very useful in avoiding lifting of operations;
   371 
   372 * HOL/record: added general record equality rule to simpset; fixed
   373 select-update simplification procedure to handle extended records as
   374 well; admit "r" as field name;
   375 
   376 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   377 other numeric types and also as the identity of groups, rings, etc.;
   378 
   379 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   380 Types nat and int belong to this axclass;
   381 
   382 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   383    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   384    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   385   two terms #m*u and #n*u are replaced by #(m+n)*u
   386     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   387   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   388     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   389 
   390 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   391 powerful prover for predicate logic but knows nothing of clasets; see
   392 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   393 
   394 * HOL: new version of "case_tac" subsumes both boolean case split and
   395 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   396 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   397 
   398 * HOL: simplification no longer dives into case-expressions: only the
   399 selector expression is simplified, but not the remaining arms; to
   400 enable full simplification of case-expressions for datatype t, you may
   401 remove t.weak_case_cong from the simpset, either globally (Delcongs
   402 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   403 
   404 * HOL/recdef: the recursion equations generated by 'recdef' for
   405 function 'f' are now called f.simps instead of f.rules; if all
   406 termination conditions are proved automatically, these simplification
   407 rules are added to the simpset, as in primrec; rules may be named
   408 individually as well, resulting in a separate list of theorems for
   409 each equation;
   410 
   411 * HOL/While is a new theory that provides a while-combinator. It
   412 permits the definition of tail-recursive functions without the
   413 provision of a termination measure. The latter is necessary once the
   414 invariant proof rule for while is applied.
   415 
   416 * HOL: new (overloaded) notation for the set of elements below/above
   417 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   418 
   419 * HOL: theorems impI, allI, ballI bound as "strip";
   420 
   421 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   422 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   423 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   424 
   425 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   426 
   427 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   428 main HOL, but was unused);
   429 
   430 * HOL: fewer consts declared as global (e.g. have to refer to
   431 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   432 
   433 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   434 in case of overlap with user translations (e.g. judgements over
   435 tuples); (note that the underlying logical represenation is still
   436 bogus);
   437 
   438 
   439 *** ZF ***
   440 
   441 * ZF: simplification automatically cancels common terms in arithmetic
   442 expressions over nat and int;
   443 
   444 * ZF: new treatment of nat to minimize type-checking: all operators
   445 coerce their operands to a natural number using the function natify,
   446 making the algebraic laws unconditional;
   447 
   448 * ZF: as above, for int: operators coerce their operands to an integer
   449 using the function intify;
   450 
   451 * ZF: the integer library now contains many of the usual laws for the
   452 orderings, including $<=, and monotonicity laws for $+ and $*;
   453 
   454 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   455 simplification;
   456 
   457 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   458 to the simplifier and classical reasoner simultaneously;
   459 
   460 
   461 *** General ***
   462 
   463 * Provers: blast_tac now handles actual object-logic rules as
   464 assumptions; note that auto_tac uses blast_tac internally as well;
   465 
   466 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   467 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   468 
   469 * Provers: delrules now handles destruct rules as well (no longer need
   470 explicit make_elim);
   471 
   472 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   473   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   474 use instead the strong form,
   475   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   476 in HOL, FOL and ZF the function cla_make_elim will create such rules
   477 from destruct-rules;
   478 
   479 * Provers: Simplifier.easy_setup provides a fast path to basic
   480 Simplifier setup for new object-logics;
   481 
   482 * Pure: AST translation rules no longer require constant head on LHS;
   483 
   484 * Pure: improved name spaces: ambiguous output is qualified; support
   485 for hiding of names;
   486 
   487 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   488 XSYMBOL_HOME; no longer need to do manual configuration in most
   489 situations;
   490 
   491 * system: compression of ML heaps images may now be controlled via -c
   492 option of isabelle and isatool usedir (currently only observed by
   493 Poly/ML);
   494 
   495 * system: isatool installfonts may handle X-Symbol fonts as well (very
   496 useful for remote X11);
   497 
   498 * system: provide TAGS file for Isabelle sources;
   499 
   500 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   501 order;
   502 
   503 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   504 timing flag supersedes proof_timing and Toplevel.trace;
   505 
   506 * ML: new combinators |>> and |>>> for incremental transformations
   507 with secondary results (e.g. certain theory extensions):
   508 
   509 * ML: PureThy.add_defs gets additional argument to indicate potential
   510 overloading (usually false);
   511 
   512 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   513 results;
   514 
   515 
   516 
   517 New in Isabelle99 (October 1999)
   518 --------------------------------
   519 
   520 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   521 
   522 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   523 are no longer simplified.  (This allows the simplifier to unfold recursive
   524 functional programs.)  To restore the old behaviour, declare
   525 
   526     Delcongs [if_weak_cong];
   527 
   528 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   529 complement;
   530 
   531 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   532 
   533 * HOL/datatype: mutual_induct_tac no longer exists --
   534   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   535 
   536 * HOL/typedef: fixed type inference for representing set; type
   537 arguments now have to occur explicitly on the rhs as type constraints;
   538 
   539 * ZF: The con_defs part of an inductive definition may no longer refer
   540 to constants declared in the same theory;
   541 
   542 * HOL, ZF: the function mk_cases, generated by the inductive
   543 definition package, has lost an argument.  To simplify its result, it
   544 uses the default simpset instead of a supplied list of theorems.
   545 
   546 * HOL/List: the constructors of type list are now Nil and Cons;
   547 
   548 * Simplifier: the type of the infix ML functions
   549         setSSolver addSSolver setSolver addSolver
   550 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   551 for packaging solvers. A solver is created via
   552         mk_solver: string -> (thm list -> int -> tactic) -> solver
   553 where the string argument is only a comment.
   554 
   555 
   556 *** Proof tools ***
   557 
   558 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   559 decision procedure for linear arithmetic. Currently it is used for
   560 types `nat', `int', and `real' in HOL (see below); it can, should and
   561 will be instantiated for other types and logics as well.
   562 
   563 * The simplifier now accepts rewrite rules with flexible heads, eg
   564      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   565   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   566   matching.
   567 
   568 
   569 *** General ***
   570 
   571 * New Isabelle/Isar subsystem provides an alternative to traditional
   572 tactical theorem proving; together with the ProofGeneral/isar user
   573 interface it offers an interactive environment for developing human
   574 readable proof documents (Isar == Intelligible semi-automated
   575 reasoning); for further information see isatool doc isar-ref,
   576 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   577 
   578 * improved and simplified presentation of theories: better HTML markup
   579 (including colors), graph views in several sizes; isatool usedir now
   580 provides a proper interface for user theories (via -P option); actual
   581 document preparation based on (PDF)LaTeX is available as well (for
   582 new-style theories only); see isatool doc system for more information;
   583 
   584 * native support for Proof General, both for classic Isabelle and
   585 Isabelle/Isar;
   586 
   587 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   588 using the graph browser tool;
   589 
   590 * Isabelle manuals now also available as PDF;
   591 
   592 * theory loader rewritten from scratch (may not be fully
   593 bug-compatible); old loadpath variable has been replaced by show_path,
   594 add_path, del_path, reset_path functions; new operations such as
   595 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   596 isatool doc ref);
   597 
   598 * improved isatool install: option -k creates KDE application icon,
   599 option -p DIR installs standalone binaries;
   600 
   601 * added ML_PLATFORM setting (useful for cross-platform installations);
   602 more robust handling of platform specific ML images for SML/NJ;
   603 
   604 * the settings environment is now statically scoped, i.e. it is never
   605 created again in sub-processes invoked from isabelle, isatool, or
   606 Isabelle;
   607 
   608 * path element specification '~~' refers to '$ISABELLE_HOME';
   609 
   610 * in locales, the "assumes" and "defines" parts may be omitted if
   611 empty;
   612 
   613 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   614 long arrows);
   615 
   616 * new print_mode "HTML";
   617 
   618 * new flag show_tags controls display of tags of theorems (which are
   619 basically just comments that may be attached by some tools);
   620 
   621 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   622 mode and goal output format:
   623 
   624 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   625 244c244
   626 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   627 ---
   628 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   629 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   630 181c181
   631 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   632 ---
   633 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   634 
   635 * function bind_thms stores lists of theorems (cf. bind_thm);
   636 
   637 * new shorthand tactics ftac, eatac, datac, fatac;
   638 
   639 * qed (and friends) now accept "" as result name; in that case the
   640 theorem is not stored, but proper checks and presentation of the
   641 result still apply;
   642 
   643 * theorem database now also indexes constants "Trueprop", "all",
   644 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   645 
   646 
   647 *** HOL ***
   648 
   649 ** HOL arithmetic **
   650 
   651 * There are now decision procedures for linear arithmetic over nat and
   652 int:
   653 
   654 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   655 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   656 are treated as atomic; subformulae not involving type `nat' or `int'
   657 are ignored; quantified subformulae are ignored unless they are
   658 positive universal or negative existential. The tactic has to be
   659 invoked by hand and can be a little bit slow. In particular, the
   660 running time is exponential in the number of occurrences of `min' and
   661 `max', and `-' on `nat'.
   662 
   663 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   664 (negated) (in)equalities among the premises and the conclusion into
   665 account (i.e. no compound formulae) and does not know about `min' and
   666 `max', and `-' on `nat'. It is fast and is used automatically by the
   667 simplifier.
   668 
   669 NB: At the moment, these decision procedures do not cope with mixed
   670 nat/int formulae where the two parts interact, such as `m < n ==>
   671 int(m) < int(n)'.
   672 
   673 * HOL/Numeral provides a generic theory of numerals (encoded
   674 efficiently as bit strings); setup for types nat/int/real is in place;
   675 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   676 int, existing theories and proof scripts may require a few additional
   677 type constraints;
   678 
   679 * integer division and remainder can now be performed on constant
   680 arguments;
   681 
   682 * many properties of integer multiplication, division and remainder
   683 are now available;
   684 
   685 * An interface to the Stanford Validity Checker (SVC) is available through the
   686 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   687 are proved automatically.  SVC must be installed separately, and its results
   688 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   689 invocation of the underlying oracle).  For SVC see
   690   http://verify.stanford.edu/SVC
   691 
   692 * IsaMakefile: the HOL-Real target now builds an actual image;
   693 
   694 
   695 ** HOL misc **
   696 
   697 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   698 (in Isabelle/Isar) -- by Gertrud Bauer;
   699 
   700 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   701 analysis for assembly languages with subtypes;
   702 
   703 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   704 -- avoids syntactic ambiguities and treats state, transition, and
   705 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   706 changed syntax and (many) tactics;
   707 
   708 * HOL/inductive: Now also handles more general introduction rules such
   709   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   710   theorems are now maintained within the theory (maintained via the
   711   "mono" attribute);
   712 
   713 * HOL/datatype: Now also handles arbitrarily branching datatypes
   714   (using function types) such as
   715 
   716   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   717 
   718 * HOL/record: record_simproc (part of the default simpset) takes care
   719 of selectors applied to updated records; record_split_tac is no longer
   720 part of the default claset; update_defs may now be removed from the
   721 simpset in many cases; COMPATIBILITY: old behavior achieved by
   722 
   723   claset_ref () := claset() addSWrapper record_split_wrapper;
   724   Delsimprocs [record_simproc]
   725 
   726 * HOL/typedef: fixed type inference for representing set; type
   727 arguments now have to occur explicitly on the rhs as type constraints;
   728 
   729 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   730 names rather than an ML expression;
   731 
   732 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   733 supplied later.  Program schemes can be defined, such as
   734     "While B C s = (if B s then While B C (C s) else s)"
   735 where the well-founded relation can be chosen after B and C have been given.
   736 
   737 * HOL/List: the constructors of type list are now Nil and Cons;
   738 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   739 course, ML tools referring to List.list.op # etc. have to be adapted;
   740 
   741 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   742 disabled by default; run isabelle with option -m HOL to get back to
   743 the original Gordon/HOL-style output;
   744 
   745 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   746 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   747 
   748 * HOL basic syntax simplified (more orthogonal): all variants of
   749 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   750 Eps operator is provided as well: "SOME x. P[x]";
   751 
   752 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   753 
   754 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   755 thus available for user theories;
   756 
   757 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   758 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   759 time;
   760 
   761 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   762 several times and then mp;
   763 
   764 
   765 *** LK ***
   766 
   767 * the notation <<...>> is now available as a notation for sequences of
   768 formulas;
   769 
   770 * the simplifier is now installed
   771 
   772 * the axiom system has been generalized (thanks to Soren Heilmann)
   773 
   774 * the classical reasoner now has a default rule database
   775 
   776 
   777 *** ZF ***
   778 
   779 * new primrec section allows primitive recursive functions to be given
   780 directly (as in HOL) over datatypes and the natural numbers;
   781 
   782 * new tactics induct_tac and exhaust_tac for induction (or case
   783 analysis) over datatypes and the natural numbers;
   784 
   785 * the datatype declaration of type T now defines the recursor T_rec;
   786 
   787 * simplification automatically does freeness reasoning for datatype
   788 constructors;
   789 
   790 * automatic type-inference, with AddTCs command to insert new
   791 type-checking rules;
   792 
   793 * datatype introduction rules are now added as Safe Introduction rules
   794 to the claset;
   795 
   796 * the syntax "if P then x else y" is now available in addition to
   797 if(P,x,y);
   798 
   799 
   800 *** Internal programming interfaces ***
   801 
   802 * tuned simplifier trace output; new flag debug_simp;
   803 
   804 * structures Vartab / Termtab (instances of TableFun) offer efficient
   805 tables indexed by indexname_ord / term_ord (compatible with aconv);
   806 
   807 * AxClass.axclass_tac lost the theory argument;
   808 
   809 * tuned current_goals_markers semantics: begin / end goal avoids
   810 printing empty lines;
   811 
   812 * removed prs and prs_fn hook, which was broken because it did not
   813 include \n in its semantics, forcing writeln to add one
   814 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   815 string -> unit if you really want to output text without newline;
   816 
   817 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   818 plain output, interface builders may have to enable 'isabelle_font'
   819 mode to get Isabelle font glyphs as before;
   820 
   821 * refined token_translation interface; INCOMPATIBILITY: output length
   822 now of type real instead of int;
   823 
   824 * theory loader actions may be traced via new ThyInfo.add_hook
   825 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   826 your own database of information attached to *whole* theories -- as
   827 opposed to intra-theory data slots offered via TheoryDataFun;
   828 
   829 * proper handling of dangling sort hypotheses (at last!);
   830 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   831 extra sort hypotheses that can be witnessed from the type signature;
   832 the force_strip_shyps flag is gone, any remaining shyps are simply
   833 left in the theorem (with a warning issued by strip_shyps_warning);
   834 
   835 
   836 
   837 New in Isabelle98-1 (October 1998)
   838 ----------------------------------
   839 
   840 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   841 
   842 * several changes of automated proof tools;
   843 
   844 * HOL: major changes to the inductive and datatype packages, including
   845 some minor incompatibilities of theory syntax;
   846 
   847 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   848 called `inj_on';
   849 
   850 * HOL: removed duplicate thms in Arith:
   851   less_imp_add_less  should be replaced by  trans_less_add1
   852   le_imp_add_le      should be replaced by  trans_le_add1
   853 
   854 * HOL: unary minus is now overloaded (new type constraints may be
   855 required);
   856 
   857 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   858 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   859 now taken as an integer constant.
   860 
   861 * Pure: ML function 'theory_of' renamed to 'theory';
   862 
   863 
   864 *** Proof tools ***
   865 
   866 * Simplifier:
   867   1. Asm_full_simp_tac is now more aggressive.
   868      1. It will sometimes reorient premises if that increases their power to
   869         simplify.
   870      2. It does no longer proceed strictly from left to right but may also
   871         rotate premises to achieve further simplification.
   872      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   873      old Asm_full_simp_tac in that it does not rotate premises.
   874   2. The simplifier now knows a little bit about nat-arithmetic.
   875 
   876 * Classical reasoner: wrapper mechanism for the classical reasoner now
   877 allows for selected deletion of wrappers, by introduction of names for
   878 wrapper functionals.  This implies that addbefore, addSbefore,
   879 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   880 and that adding two tactics with the same name overwrites the first
   881 one (emitting a warning).
   882   type wrapper = (int -> tactic) -> (int -> tactic)
   883   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   884   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   885   delWrapper, delSWrapper: claset *  string            -> claset
   886   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   887 
   888 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   889 semantics; addbefore now affects only the unsafe part of step_tac
   890 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   891 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   892 by Force_tac;
   893 
   894 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   895 compWrapper; added safe wrapper (and access functions for it);
   896 
   897 * HOL/split_all_tac is now much faster and fails if there is nothing
   898 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   899 and the names of the automatically generated variables have changed.
   900 split_all_tac has moved within claset() from unsafe wrappers to safe
   901 wrappers, which means that !!-bound variables are split much more
   902 aggressively, and safe_tac and clarify_tac now split such variables.
   903 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   904 Note: the same holds for record_split_tac, which does the job of
   905 split_all_tac for record fields.
   906 
   907 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   908 permanently to the default simpset using Addsplits just like
   909 Addsimps. They can be removed via Delsplits just like
   910 Delsimps. Lower-case versions are also available.
   911 
   912 * HOL/Simplifier: The rule split_if is now part of the default
   913 simpset. This means that the simplifier will eliminate all occurrences
   914 of if-then-else in the conclusion of a goal. To prevent this, you can
   915 either remove split_if completely from the default simpset by
   916 `Delsplits [split_if]' or remove it in a specific call of the
   917 simplifier using `... delsplits [split_if]'.  You can also add/delete
   918 other case splitting rules to/from the default simpset: every datatype
   919 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   920 t is the name of the datatype).
   921 
   922 * Classical reasoner / Simplifier combination: new force_tac (and
   923 derivatives Force_tac, force) combines rewriting and classical
   924 reasoning (and whatever other tools) similarly to auto_tac, but is
   925 aimed to solve the given subgoal completely.
   926 
   927 
   928 *** General ***
   929 
   930 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   931 and `goalw': the theory is no longer needed as an explicit argument -
   932 the current theory context is used; assumptions are no longer returned
   933 at the ML-level unless one of them starts with ==> or !!; it is
   934 recommended to convert to these new commands using isatool fixgoal
   935 (backup your sources first!);
   936 
   937 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   938 the current theory context, and 'theory' to lookup stored theories;
   939 
   940 * new theory section 'locale' for declaring constants, assumptions and
   941 definitions that have local scope;
   942 
   943 * new theory section 'nonterminals' for purely syntactic types;
   944 
   945 * new theory section 'setup' for generic ML setup functions
   946 (e.g. package initialization);
   947 
   948 * the distribution now includes Isabelle icons: see
   949 lib/logo/isabelle-{small,tiny}.xpm;
   950 
   951 * isatool install - install binaries with absolute references to
   952 ISABELLE_HOME/bin;
   953 
   954 * isatool logo -- create instances of the Isabelle logo (as EPS);
   955 
   956 * print mode 'emacs' reserved for Isamode;
   957 
   958 * support multiple print (ast) translations per constant name;
   959 
   960 * theorems involving oracles are now printed with a suffixed [!];
   961 
   962 
   963 *** HOL ***
   964 
   965 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   966 
   967 * HOL/inductive package reorganized and improved: now supports mutual
   968 definitions such as
   969 
   970   inductive EVEN ODD
   971     intrs
   972       null "0 : EVEN"
   973       oddI "n : EVEN ==> Suc n : ODD"
   974       evenI "n : ODD ==> Suc n : EVEN"
   975 
   976 new theorem list "elims" contains an elimination rule for each of the
   977 recursive sets; inductive definitions now handle disjunctive premises
   978 correctly (also ZF);
   979 
   980 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   981 "mutual_induct" no longer exists - the induction rule is always
   982 contained in "induct";
   983 
   984 
   985 * HOL/datatype package re-implemented and greatly improved: now
   986 supports mutually recursive datatypes such as
   987 
   988   datatype
   989     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   990             | SUM ('a aexp) ('a aexp)
   991             | DIFF ('a aexp) ('a aexp)
   992             | NUM 'a
   993   and
   994     'a bexp = LESS ('a aexp) ('a aexp)
   995             | AND ('a bexp) ('a bexp)
   996             | OR ('a bexp) ('a bexp)
   997 
   998 as well as indirectly recursive datatypes such as
   999 
  1000   datatype
  1001     ('a, 'b) term = Var 'a
  1002                   | App 'b ((('a, 'b) term) list)
  1003 
  1004 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1005 induction on mutually / indirectly recursive datatypes.
  1006 
  1007 Primrec equations are now stored in theory and can be accessed via
  1008 <function_name>.simps.
  1009 
  1010 INCOMPATIBILITIES:
  1011 
  1012   - Theories using datatypes must now have theory Datatype as an
  1013     ancestor.
  1014   - The specific <typename>.induct_tac no longer exists - use the
  1015     generic induct_tac instead.
  1016   - natE has been renamed to nat.exhaust - use exhaust_tac
  1017     instead of res_inst_tac ... natE. Note that the variable
  1018     names in nat.exhaust differ from the names in natE, this
  1019     may cause some "fragile" proofs to fail.
  1020   - The theorems split_<typename>_case and split_<typename>_case_asm
  1021     have been renamed to <typename>.split and <typename>.split_asm.
  1022   - Since default sorts of type variables are now handled correctly,
  1023     some datatype definitions may have to be annotated with explicit
  1024     sort constraints.
  1025   - Primrec definitions no longer require function name and type
  1026     of recursive argument.
  1027 
  1028 Consider using isatool fixdatatype to adapt your theories and proof
  1029 scripts to the new package (backup your sources first!).
  1030 
  1031 
  1032 * HOL/record package: considerably improved implementation; now
  1033 includes concrete syntax for record types, terms, updates; theorems
  1034 for surjective pairing and splitting !!-bound record variables; proof
  1035 support is as follows:
  1036 
  1037   1) standard conversions (selectors or updates applied to record
  1038 constructor terms) are part of the standard simpset;
  1039 
  1040   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1041 made part of standard simpset and claset via addIffs;
  1042 
  1043   3) a tactic for record field splitting (record_split_tac) is part of
  1044 the standard claset (addSWrapper);
  1045 
  1046 To get a better idea about these rules you may retrieve them via
  1047 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1048 the name of your record type.
  1049 
  1050 The split tactic 3) conceptually simplifies by the following rule:
  1051 
  1052   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1053 
  1054 Thus any record variable that is bound by meta-all will automatically
  1055 blow up into some record constructor term, consequently the
  1056 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1057 solve record problems automatically.
  1058 
  1059 
  1060 * reorganized the main HOL image: HOL/Integ and String loaded by
  1061 default; theory Main includes everything;
  1062 
  1063 * automatic simplification of integer sums and comparisons, using cancellation;
  1064 
  1065 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1066 
  1067 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1068 
  1069 * many new identities for unions, intersections, set difference, etc.;
  1070 
  1071 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1072 called split_if, split_split, split_sum_case and split_nat_case (to go
  1073 with add/delsplits);
  1074 
  1075 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1076 (?x::unit) = (); this is made part of the default simpset, which COULD
  1077 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1078 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1079 unit_abs_eta_conv is added in order to counter the effect of
  1080 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1081 %u.f();
  1082 
  1083 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1084 makes more sense);
  1085 
  1086 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1087   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1088   disjointness reasoning but breaking a few old proofs.
  1089 
  1090 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1091 to 'converse' from 'inverse' (for compatibility with ZF and some
  1092 literature);
  1093 
  1094 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1095 the well-founded relation;
  1096 
  1097 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1098     Compl A.  The "Compl" syntax remains available as input syntax for this
  1099     release ONLY.
  1100 
  1101 * HOL/Update: new theory of function updates:
  1102     f(a:=b) == %x. if x=a then b else f x
  1103 may also be iterated as in f(a:=b,c:=d,...);
  1104 
  1105 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1106 
  1107 * HOL/List:
  1108   - new function list_update written xs[i:=v] that updates the i-th
  1109     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1110   - new function `upt' written [i..j(] which generates the list
  1111     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1112     bound write [i..j], which is a shorthand for [i..j+1(].
  1113   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1114 
  1115 * HOL/Arith:
  1116   - removed 'pred' (predecessor) function;
  1117   - generalized some theorems about n-1;
  1118   - many new laws about "div" and "mod";
  1119   - new laws about greatest common divisors (see theory ex/Primes);
  1120 
  1121 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1122 instead of "inverse";
  1123 
  1124 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1125   of the multiset ordering;
  1126 
  1127 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1128   (not included by default);
  1129 
  1130 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1131 
  1132 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1133   programs, i.e. different program variables may have different types.
  1134 
  1135 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1136   [previously, this check worked only if the rewrite rule was unconditional]
  1137   Now rew can involve either definitions or equalities (either == or =).
  1138 
  1139 
  1140 *** ZF ***
  1141 
  1142 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1143   only the theorems proved on ZF.ML;
  1144 
  1145 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1146   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1147   disjointness reasoning but breaking a few old proofs.
  1148 
  1149 * ZF/Update: new theory of function updates
  1150     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1151   may also be iterated as in f(a:=b,c:=d,...);
  1152 
  1153 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1154 
  1155 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1156   [previously, this check worked only if the rewrite rule was unconditional]
  1157   Now rew can involve either definitions or equalities (either == or =).
  1158 
  1159 * case_tac provided for compatibility with HOL
  1160     (like the old excluded_middle_tac, but with subgoals swapped)
  1161 
  1162 
  1163 *** Internal programming interfaces ***
  1164 
  1165 * Pure: several new basic modules made available for general use, see
  1166 also src/Pure/README;
  1167 
  1168 * improved the theory data mechanism to support encapsulation (data
  1169 kind name replaced by private Object.kind, acting as authorization
  1170 key); new type-safe user interface via functor TheoryDataFun; generic
  1171 print_data function becomes basically useless;
  1172 
  1173 * removed global_names compatibility flag -- all theory declarations
  1174 are qualified by default;
  1175 
  1176 * module Pure/Syntax now offers quote / antiquote translation
  1177 functions (useful for Hoare logic etc. with implicit dependencies);
  1178 see HOL/ex/Antiquote for an example use;
  1179 
  1180 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1181 cterm -> thm;
  1182 
  1183 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1184 subgoal;
  1185 
  1186 * Display.print_goals function moved to Locale.print_goals;
  1187 
  1188 * standard print function for goals supports current_goals_markers
  1189 variable for marking begin of proof, end of proof, start of goal; the
  1190 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1191 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1192 for example;
  1193 
  1194 
  1195 
  1196 New in Isabelle98 (January 1998)
  1197 --------------------------------
  1198 
  1199 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1200 
  1201 * changed lexical syntax of terms / types: dots made part of long
  1202 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1203 
  1204 * simpset (and claset) reference variable replaced by functions
  1205 simpset / simpset_ref;
  1206 
  1207 * no longer supports theory aliases (via merge) and non-trivial
  1208 implicit merge of thms' signatures;
  1209 
  1210 * most internal names of constants changed due to qualified names;
  1211 
  1212 * changed Pure/Sequence interface (see Pure/seq.ML);
  1213 
  1214 
  1215 *** General Changes ***
  1216 
  1217 * hierachically structured name spaces (for consts, types, axms, thms
  1218 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1219 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1220 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1221 long_names for fully qualified output names; NOTE: ML programs
  1222 (special tactics, packages etc.) referring to internal names may have
  1223 to be adapted to cope with fully qualified names; in case of severe
  1224 backward campatibility problems try setting 'global_names' at compile
  1225 time to have enrything declared within a flat name space; one may also
  1226 fine tune name declarations in theories via the 'global' and 'local'
  1227 section;
  1228 
  1229 * reimplemented the implicit simpset and claset using the new anytype
  1230 data filed in signatures; references simpset:simpset ref etc. are
  1231 replaced by functions simpset:unit->simpset and
  1232 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1233 to patch your ML files accordingly;
  1234 
  1235 * HTML output now includes theory graph data for display with Java
  1236 applet or isatool browser; data generated automatically via isatool
  1237 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1238 
  1239 * defs may now be conditional; improved rewrite_goals_tac to handle
  1240 conditional equations;
  1241 
  1242 * defs now admits additional type arguments, using TYPE('a) syntax;
  1243 
  1244 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1245 creates a new theory node; implicit merge of thms' signatures is
  1246 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1247 transfer:theory->thm->thm in (rare) cases;
  1248 
  1249 * improved handling of draft signatures / theories; draft thms (and
  1250 ctyps, cterms) are automatically promoted to real ones;
  1251 
  1252 * slightly changed interfaces for oracles: admit many per theory, named
  1253 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1254 
  1255 * print_goals: optional output of const types (set show_consts and
  1256 show_types);
  1257 
  1258 * improved output of warnings (###) and errors (***);
  1259 
  1260 * subgoal_tac displays a warning if the new subgoal has type variables;
  1261 
  1262 * removed old README and Makefiles;
  1263 
  1264 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1265 
  1266 * removed obsolete init_pps and init_database;
  1267 
  1268 * deleted the obsolete tactical STATE, which was declared by
  1269     fun STATE tacfun st = tacfun st st;
  1270 
  1271 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1272 (which abbreviates $HOME);
  1273 
  1274 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1275 use isatool fixseq to adapt your ML programs (this works for fully
  1276 qualified references to the Sequence structure only!);
  1277 
  1278 * use_thy no longer requires writable current directory; it always
  1279 reloads .ML *and* .thy file, if either one is out of date;
  1280 
  1281 
  1282 *** Classical Reasoner ***
  1283 
  1284 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1285 tactics that use classical reasoning to simplify a subgoal without
  1286 splitting it into several subgoals;
  1287 
  1288 * Safe_tac: like safe_tac but uses the default claset;
  1289 
  1290 
  1291 *** Simplifier ***
  1292 
  1293 * added simplification meta rules:
  1294     (asm_)(full_)simplify: simpset -> thm -> thm;
  1295 
  1296 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1297 logics (again);
  1298 
  1299 * added prems argument to simplification procedures;
  1300 
  1301 * HOL, FOL, ZF: added infix function `addsplits':
  1302   instead of `<simpset> setloop (split_tac <thms>)'
  1303   you can simply write `<simpset> addsplits <thms>'
  1304 
  1305 
  1306 *** Syntax ***
  1307 
  1308 * TYPE('a) syntax for type reflection terms;
  1309 
  1310 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1311 
  1312 * pretty printer: changed order of mixfix annotation preference (again!);
  1313 
  1314 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1315 
  1316 
  1317 *** HOL ***
  1318 
  1319 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1320   with `addloop' of the simplifier to faciliate case splitting in premises.
  1321 
  1322 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1323 
  1324 * HOL/Auth: new protocol proofs including some for the Internet
  1325   protocol TLS;
  1326 
  1327 * HOL/Map: new theory of `maps' a la VDM;
  1328 
  1329 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1330 cancelling out common nat summands from =, <, <= (in)equalities, or
  1331 differences; simplification procedures nat_cancel_factor for
  1332 cancelling common factor from =, <, <= (in)equalities over natural
  1333 sums; nat_cancel contains both kinds of procedures, it is installed by
  1334 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1335 
  1336 * HOL/simplifier: terms of the form
  1337   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1338   are rewritten to
  1339   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1340   and those of the form
  1341   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1342   are rewritten to
  1343   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1344 
  1345 * HOL/datatype
  1346   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1347 
  1348   P(t_case f1 ... fn x) =
  1349      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1350         ...
  1351        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1352      )
  1353 
  1354   and a theorem `split_t_case_asm' of the form
  1355 
  1356   P(t_case f1 ... fn x) =
  1357     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1358         ...
  1359        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1360      )
  1361   which can be added to a simpset via `addsplits'. The existing theorems
  1362   expand_list_case and expand_option_case have been renamed to
  1363   split_list_case and split_option_case.
  1364 
  1365 * HOL/Arithmetic:
  1366   - `pred n' is automatically converted to `n-1'.
  1367     Users are strongly encouraged not to use `pred' any longer,
  1368     because it will disappear altogether at some point.
  1369   - Users are strongly encouraged to write "0 < n" rather than
  1370     "n ~= 0". Theorems and proof tools have been modified towards this
  1371     `standard'.
  1372 
  1373 * HOL/Lists:
  1374   the function "set_of_list" has been renamed "set" (and its theorems too);
  1375   the function "nth" now takes its arguments in the reverse order and
  1376   has acquired the infix notation "!" as in "xs!n".
  1377 
  1378 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1379 
  1380 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1381   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1382 
  1383 * HOL/record: extensible records with schematic structural subtyping
  1384 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1385 still lacks various theorems and concrete record syntax;
  1386 
  1387 
  1388 *** HOLCF ***
  1389 
  1390 * removed "axioms" and "generated by" sections;
  1391 
  1392 * replaced "ops" section by extended "consts" section, which is capable of
  1393   handling the continuous function space "->" directly;
  1394 
  1395 * domain package:
  1396   . proves theorems immediately and stores them in the theory,
  1397   . creates hierachical name space,
  1398   . now uses normal mixfix annotations (instead of cinfix...),
  1399   . minor changes to some names and values (for consistency),
  1400   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1401   . separator between mutual domain defs: changed "," to "and",
  1402   . improved handling of sort constraints;  now they have to
  1403     appear on the left-hand side of the equations only;
  1404 
  1405 * fixed LAM <x,y,zs>.b syntax;
  1406 
  1407 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1408 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1409 
  1410 
  1411 *** FOL and ZF ***
  1412 
  1413 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1414   with `addloop' of the simplifier to faciliate case splitting in premises.
  1415 
  1416 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1417 in HOL, they strip ALL and --> from proved theorems;
  1418 
  1419 
  1420 
  1421 New in Isabelle94-8 (May 1997)
  1422 ------------------------------
  1423 
  1424 *** General Changes ***
  1425 
  1426 * new utilities to build / run / maintain Isabelle etc. (in parts
  1427 still somewhat experimental); old Makefiles etc. still functional;
  1428 
  1429 * new 'Isabelle System Manual';
  1430 
  1431 * INSTALL text, together with ./configure and ./build scripts;
  1432 
  1433 * reimplemented type inference for greater efficiency, better error
  1434 messages and clean internal interface;
  1435 
  1436 * prlim command for dealing with lots of subgoals (an easier way of
  1437 setting goals_limit);
  1438 
  1439 
  1440 *** Syntax ***
  1441 
  1442 * supports alternative (named) syntax tables (parser and pretty
  1443 printer); internal interface is provided by add_modesyntax(_i);
  1444 
  1445 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1446 be used in conjunction with the Isabelle symbol font; uses the
  1447 "symbols" syntax table;
  1448 
  1449 * added token_translation interface (may translate name tokens in
  1450 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1451 the current print_mode); IMPORTANT: user print translation functions
  1452 are responsible for marking newly introduced bounds
  1453 (Syntax.mark_boundT);
  1454 
  1455 * token translations for modes "xterm" and "xterm_color" that display
  1456 names in bold, underline etc. or colors (which requires a color
  1457 version of xterm);
  1458 
  1459 * infixes may now be declared with names independent of their syntax;
  1460 
  1461 * added typed_print_translation (like print_translation, but may
  1462 access type of constant);
  1463 
  1464 
  1465 *** Classical Reasoner ***
  1466 
  1467 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1468 some limitations.  Blast_tac...
  1469   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1470   + ignores elimination rules that don't have the correct format
  1471         (the conclusion MUST be a formula variable)
  1472   + ignores types, which can make HOL proofs fail
  1473   + rules must not require higher-order unification, e.g. apply_type in ZF
  1474     [message "Function Var's argument not a bound variable" relates to this]
  1475   + its proof strategy is more general but can actually be slower
  1476 
  1477 * substitution with equality assumptions no longer permutes other
  1478 assumptions;
  1479 
  1480 * minor changes in semantics of addafter (now called addaltern); renamed
  1481 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1482 (and access functions for it);
  1483 
  1484 * improved combination of classical reasoner and simplifier:
  1485   + functions for handling clasimpsets
  1486   + improvement of addss: now the simplifier is called _after_ the
  1487     safe steps.
  1488   + safe variant of addss called addSss: uses safe simplifications
  1489     _during_ the safe steps. It is more complete as it allows multiple
  1490     instantiations of unknowns (e.g. with slow_tac).
  1491 
  1492 *** Simplifier ***
  1493 
  1494 * added interface for simplification procedures (functions that
  1495 produce *proven* rewrite rules on the fly, depending on current
  1496 redex);
  1497 
  1498 * ordering on terms as parameter (used for ordered rewriting);
  1499 
  1500 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1501 
  1502 * the solver is now split into a safe and an unsafe part.
  1503 This should be invisible for the normal user, except that the
  1504 functions setsolver and addsolver have been renamed to setSolver and
  1505 addSolver; added safe_asm_full_simp_tac;
  1506 
  1507 
  1508 *** HOL ***
  1509 
  1510 * a generic induction tactic `induct_tac' which works for all datatypes and
  1511 also for type `nat';
  1512 
  1513 * a generic case distinction tactic `exhaust_tac' which works for all
  1514 datatypes and also for type `nat';
  1515 
  1516 * each datatype comes with a function `size';
  1517 
  1518 * patterns in case expressions allow tuple patterns as arguments to
  1519 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1520 
  1521 * primrec now also works with type nat;
  1522 
  1523 * recdef: a new declaration form, allows general recursive functions to be
  1524 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1525 
  1526 * the constant for negation has been renamed from "not" to "Not" to
  1527 harmonize with FOL, ZF, LK, etc.;
  1528 
  1529 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1530 infinite lists;
  1531 
  1532 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1533 
  1534 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1535 problems in commutative rings, using axiomatic type classes for + and *;
  1536 
  1537 * more examples in HOL/MiniML and HOL/Auth;
  1538 
  1539 * more default rewrite rules for quantifiers, union/intersection;
  1540 
  1541 * a new constant `arbitrary == @x.False';
  1542 
  1543 * HOLCF/IOA replaces old HOL/IOA;
  1544 
  1545 * HOLCF changes: derived all rules and arities
  1546   + axiomatic type classes instead of classes
  1547   + typedef instead of faking type definitions
  1548   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1549   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1550   + eliminated the types void, one, tr
  1551   + use unit lift and bool lift (with translations) instead of one and tr
  1552   + eliminated blift from Lift3.thy (use Def instead of blift)
  1553   all eliminated rules are derived as theorems --> no visible changes ;
  1554 
  1555 
  1556 *** ZF ***
  1557 
  1558 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1559 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1560 as ZF_cs addSIs [equalityI];
  1561 
  1562 
  1563 
  1564 New in Isabelle94-7 (November 96)
  1565 ---------------------------------
  1566 
  1567 * allowing negative levels (as offsets) in prlev and choplev;
  1568 
  1569 * super-linear speedup for large simplifications;
  1570 
  1571 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1572 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1573 FAIL); can suppress it using the command Delsimps (ex_simps @
  1574 all_simps); De Morgan laws are also now included, by default;
  1575 
  1576 * improved printing of ==>  :  ~:
  1577 
  1578 * new object-logic "Sequents" adds linear logic, while replacing LK
  1579 and Modal (thanks to Sara Kalvala);
  1580 
  1581 * HOL/Auth: correctness proofs for authentication protocols;
  1582 
  1583 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1584 examples on HOL/Auth);
  1585 
  1586 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1587 the rewriter and classical reasoner simultaneously;
  1588 
  1589 * function uresult no longer returns theorems in "standard" format;
  1590 regain previous version by: val uresult = standard o uresult;
  1591 
  1592 
  1593 
  1594 New in Isabelle94-6
  1595 -------------------
  1596 
  1597 * oracles -- these establish an interface between Isabelle and trusted
  1598 external reasoners, which may deliver results as theorems;
  1599 
  1600 * proof objects (in particular record all uses of oracles);
  1601 
  1602 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1603 
  1604 * "constdefs" section in theory files;
  1605 
  1606 * "primrec" section (HOL) no longer requires names;
  1607 
  1608 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1609 
  1610 
  1611 
  1612 New in Isabelle94-5
  1613 -------------------
  1614 
  1615 * reduced space requirements;
  1616 
  1617 * automatic HTML generation from theories;
  1618 
  1619 * theory files no longer require "..." (quotes) around most types;
  1620 
  1621 * new examples, including two proofs of the Church-Rosser theorem;
  1622 
  1623 * non-curried (1994) version of HOL is no longer distributed;
  1624 
  1625 
  1626 
  1627 New in Isabelle94-4
  1628 -------------------
  1629 
  1630 * greatly reduced space requirements;
  1631 
  1632 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1633 
  1634 * searchable theorem database (see the section "Retrieving theorems" on
  1635 page 8 of the Reference Manual);
  1636 
  1637 * new examples, including Grabczewski's monumental case study of the
  1638 Axiom of Choice;
  1639 
  1640 * The previous version of HOL renamed to Old_HOL;
  1641 
  1642 * The new version of HOL (previously called CHOL) uses a curried syntax
  1643 for functions.  Application looks like f a b instead of f(a,b);
  1644 
  1645 * Mutually recursive inductive definitions finally work in HOL;
  1646 
  1647 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1648 translates to the operator "split";
  1649 
  1650 
  1651 
  1652 New in Isabelle94-3
  1653 -------------------
  1654 
  1655 * new infix operator, addss, allowing the classical reasoner to
  1656 perform simplification at each step of its search.  Example:
  1657         fast_tac (cs addss ss)
  1658 
  1659 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1660 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1661 look like (a,b) instead of <a,b>;
  1662 
  1663 * PLEASE NOTE: CHOL will eventually replace HOL!
  1664 
  1665 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1666 It translates to the operator "split".  A new theory of integers is available;
  1667 
  1668 * In ZF, integer numerals now denote two's-complement binary integers.
  1669 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1670 
  1671 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1672 of the Axiom of Choice;
  1673 
  1674 
  1675 
  1676 New in Isabelle94-2
  1677 -------------------
  1678 
  1679 * Significantly faster resolution;
  1680 
  1681 * the different sections in a .thy file can now be mixed and repeated
  1682 freely;
  1683 
  1684 * Database of theorems for FOL, HOL and ZF.  New
  1685 commands including qed, qed_goal and bind_thm store theorems in the database.
  1686 
  1687 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1688 a given theory (thms_of), or find out what theory a theorem was proved in
  1689 (theory_of_thm);
  1690 
  1691 * Bugs fixed in the inductive definition and datatype packages;
  1692 
  1693 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1694 and HOL_dup_cs obsolete;
  1695 
  1696 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1697 have been removed;
  1698 
  1699 * Simpler definition of function space in ZF;
  1700 
  1701 * new results about cardinal and ordinal arithmetic in ZF;
  1702 
  1703 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1704 types;
  1705 
  1706 
  1707 $Id$