NEWS
author wenzelm
Wed Jan 10 20:18:55 2001 +0100 (2001-01-10)
changeset 10858 479dad7b3b41
parent 10856 e8a5340418b6
child 10862 857688d775b0
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 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 "$";
    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 
    51 *** Isar ***
    52 
    53 * Pure: Isar now suffers initial goal statements to contain unbound
    54 schematic variables (this does not conform to actual readable proof
    55 documents, due to unpredictable outcome and non-compositional proof
    56 checking); users who know what they are doing may use schematic goals
    57 for Prolog-style synthesis of proven results;
    58 
    59 * Pure: assumption method (an implicit finishing) now handles actual
    60 rules as well;
    61 
    62 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    63 initial goal, declare "that" only as Pure intro (only for single
    64 steps); the "that" rule assumption may now be involved in implicit
    65 finishing, thus ".." becomes a feasible for trivial obtains;
    66 
    67 * Pure: default proof step now includes 'intro_classes'; thus trivial
    68 instance proofs may be performed by "..";
    69 
    70 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    71 statements as well;
    72 
    73 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    74 rule (as well as the assumption rule);
    75 
    76 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    77 lemmas, using the graph browser tool;
    78 
    79 * HOL: improved method 'induct' --- now handles non-atomic goals
    80 (potential INCOMPATIBILITY); tuned error handling;
    81 
    82 * HOL: cases and induct rules now provide explicit hints about the
    83 number of facts to be consumed (0 for "type" and 1 for "set" rules);
    84 any remaining facts are inserted into the goal verbatim;
    85 
    86 * HOL: local contexts (aka cases) may now contain term bindings as
    87 well; the 'cases' and 'induct' methods new provide a ?case binding for
    88 the result to be shown in each case;
    89 
    90 * HOL: added 'recdef_tc' command;
    91 
    92 
    93 *** HOL ***
    94 
    95 * HOL/Library: a collection of generic theories to be used together
    96 with main HOL; the theory loader path already includes this directory
    97 by default; the following existing theories have been moved here:
    98 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
    99 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   100 
   101 * HOL basics: added overloaded operations "inverse" and "divide"
   102 (infix "/"), syntax for generic "abs" operation, generic summation
   103 operator;
   104 
   105 * HOL/typedef: simplified package, provide more useful rules (see also
   106 HOL/subset.thy);
   107 
   108 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals and 
   109 Fleuriot's mechanization of analysis;
   110 
   111 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   112 
   113 
   114 *** CTT ***
   115 
   116 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   117 "lam" is displayed as TWO lambda-symbols
   118 
   119 * CTT: theory Main now available, containing everything (that is, Bool
   120 and Arith);
   121 
   122 
   123 *** General ***
   124 
   125 * print modes "brackets" and "no_brackets" control output of nested =>
   126 (types) and ==> (props); the default behaviour is "brackets";
   127 
   128 * system: support Poly/ML 4.0 (current beta versions);
   129 
   130 * Pure: the Simplifier has been implemented properly as a derived rule
   131 outside of the actual kernel (at last!); the overall performance
   132 penalty in practical applications is about 50%, while reliability of
   133 the Isabelle inference kernel has been greatly improved;
   134 
   135 * Provers: fast_tac (and friends) now handle actual object-logic rules
   136 as assumptions as well;
   137 
   138 
   139 
   140 New in Isabelle99-1 (October 2000)
   141 ----------------------------------
   142 
   143 *** Overview of INCOMPATIBILITIES ***
   144 
   145 * HOL: simplification of natural numbers is much changed; to partly
   146 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   147 issue the following ML commands:
   148 
   149   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   150   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   151 
   152 * HOL: simplification no longer dives into case-expressions; this is
   153 controlled by "t.weak_case_cong" for each datatype t;
   154 
   155 * HOL: nat_less_induct renamed to less_induct;
   156 
   157 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   158 fixsome to patch .thy and .ML sources automatically;
   159 
   160   select_equality  -> some_equality
   161   select_eq_Ex     -> some_eq_ex
   162   selectI2EX       -> someI2_ex
   163   selectI2         -> someI2
   164   selectI          -> someI
   165   select1_equality -> some1_equality
   166   Eps_sym_eq       -> some_sym_eq_trivial
   167   Eps_eq           -> some_eq_trivial
   168 
   169 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   170 
   171 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   172 instead);
   173 
   174 * HOL: the recursion equations generated by 'recdef' are now called
   175 f.simps instead of f.rules;
   176 
   177 * HOL: qed_spec_mp now also handles bounded ALL as well;
   178 
   179 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   180 sometimes be needed;
   181 
   182 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   183 
   184 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   185 
   186 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   187 product is now "<*>" instead of "Times"; the lexicographic product is
   188 now "<*lex*>" instead of "**";
   189 
   190 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   191 of main HOL, but was unused); better use HOL's datatype package;
   192 
   193 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   194 the old syntax may be recovered as follows:
   195 
   196   syntax (symbols)
   197     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   198       (infixl "\\<oplus>" 100)
   199 
   200 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   201 
   202 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   203 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   204 internally;
   205 
   206 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   207 changed from A/r to A//r;
   208 
   209 * ZF: new treatment of arithmetic (nat & int) may break some old
   210 proofs;
   211 
   212 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   213 rulify -> rule_format, elimify -> elim_format, ...);
   214 
   215 * Isar/Provers: intro/elim/dest attributes changed; renamed
   216 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   217 should have to change intro!! to intro? only); replaced "delrule" by
   218 "rule del";
   219 
   220 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   221 
   222 * Provers: strengthened force_tac by using new first_best_tac;
   223 
   224 * LaTeX document preparation: several changes of isabelle.sty (see
   225 lib/texinputs);
   226 
   227 
   228 *** Document preparation ***
   229 
   230 * formal comments (text blocks etc.) in new-style theories may now
   231 contain antiquotations of thm/prop/term/typ/text to be presented
   232 according to latex print mode; concrete syntax is like this:
   233 @{term[show_types] "f(x) = a + x"};
   234 
   235 * isatool mkdir provides easy setup of Isabelle session directories,
   236 including proper document sources;
   237 
   238 * generated LaTeX sources are now deleted after successful run
   239 (isatool document -c); may retain a copy somewhere else via -D option
   240 of isatool usedir;
   241 
   242 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   243 style files, achieving self-contained LaTeX sources and simplifying
   244 LaTeX debugging;
   245 
   246 * old-style theories now produce (crude) LaTeX output as well;
   247 
   248 * browser info session directories are now self-contained (may be put
   249 on WWW server seperately); improved graphs of nested sessions; removed
   250 graph for 'all sessions';
   251 
   252 * several improvements in isabelle style files; \isabellestyle{it}
   253 produces fake math mode output; \isamarkupheader is now \section by
   254 default; see lib/texinputs/isabelle.sty etc.;
   255 
   256 
   257 *** Isar ***
   258 
   259 * Isar/Pure: local results and corresponding term bindings are now
   260 subject to Hindley-Milner polymorphism (similar to ML); this
   261 accommodates incremental type-inference very nicely;
   262 
   263 * Isar/Pure: new derived language element 'obtain' supports
   264 generalized existence reasoning;
   265 
   266 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   267 support accumulation of results, without applying any rules yet;
   268 useful to collect intermediate results without explicit name
   269 references, and for use with transitivity rules with more than 2
   270 premises;
   271 
   272 * Isar/Pure: scalable support for case-analysis type proofs: new
   273 'case' language element refers to local contexts symbolically, as
   274 produced by certain proof methods; internally, case names are attached
   275 to theorems as "tags";
   276 
   277 * Isar/Pure: theory command 'hide' removes declarations from
   278 class/type/const name spaces;
   279 
   280 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   281 indicate potential overloading;
   282 
   283 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   284 
   285 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   286 "{a,b,c}" instead of {a,b,c};
   287 
   288 * Isar/Pure now provides its own version of intro/elim/dest
   289 attributes; useful for building new logics, but beware of confusion
   290 with the version in Provers/classical;
   291 
   292 * Isar/Pure: the local context of (non-atomic) goals is provided via
   293 case name 'antecedent';
   294 
   295 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   296 to the current context is now done automatically);
   297 
   298 * Isar/Pure: theory command 'method_setup' provides a simple interface
   299 for definining proof methods in ML;
   300 
   301 * Isar/Provers: intro/elim/dest attributes changed; renamed
   302 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   303 most cases, one should have to change intro!! to intro? only);
   304 replaced "delrule" by "rule del";
   305 
   306 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   307 'symmetric' attribute (the latter supercedes [RS sym]);
   308 
   309 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   310 method modifier); 'simp' method: 'only:' modifier removes loopers as
   311 well (including splits);
   312 
   313 * Isar/Provers: Simplifier and Classical methods now support all kind
   314 of modifiers used in the past, including 'cong', 'iff', etc.
   315 
   316 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   317 of Simplifier and Classical reasoner);
   318 
   319 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   320 now support named cases; major packages (inductive, datatype, primrec,
   321 recdef) support case names and properly name parameters;
   322 
   323 * Isar/HOL: new transitivity rules for substitution in inequalities --
   324 monotonicity conditions are extracted to be proven at end of
   325 calculations;
   326 
   327 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   328 method anyway;
   329 
   330 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   331 split_if split_if_asm; datatype package provides theorems foo.splits =
   332 foo.split foo.split_asm for each datatype;
   333 
   334 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   335 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   336 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   337 use "(cases (simplified))" method in proper proof texts);
   338 
   339 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   340 
   341 * Isar: names of theorems etc. may be natural numbers as well;
   342 
   343 * Isar: 'pr' command: optional arguments for goals_limit and
   344 ProofContext.prems_limit; no longer prints theory contexts, but only
   345 proof states;
   346 
   347 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   348 additional print modes to be specified; e.g. "pr(latex)" will print
   349 proof state according to the Isabelle LaTeX style;
   350 
   351 * Isar: improved support for emulating tactic scripts, including proof
   352 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   353 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   354 (for HOL datatypes);
   355 
   356 * Isar: simplified (more robust) goal selection of proof methods: 1st
   357 goal, all goals, or explicit goal specifier (tactic emulation); thus
   358 'proof method scripts' have to be in depth-first order;
   359 
   360 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   361 
   362 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   363 should instead use individual commands for printing items
   364 (print_commands, print_methods etc.);
   365 
   366 * Isar: added 'nothing' --- the empty list of theorems;
   367 
   368 
   369 *** HOL ***
   370 
   371 * HOL/MicroJava: formalization of a fragment of Java, together with a
   372 corresponding virtual machine and a specification of its bytecode
   373 verifier and a lightweight bytecode verifier, including proofs of
   374 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   375 Cornelia Pusch (see also the homepage of project Bali at
   376 http://isabelle.in.tum.de/Bali/);
   377 
   378 * HOL/Algebra: new theory of rings and univariate polynomials, by
   379 Clemens Ballarin;
   380 
   381 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   382 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   383 Rasmussen;
   384 
   385 * HOL/Lattice: fundamental concepts of lattice theory and order
   386 structures, including duals, properties of bounds versus algebraic
   387 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   388 Theorem for complete lattices etc.; may also serve as a demonstration
   389 for abstract algebraic reasoning using axiomatic type classes, and
   390 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   391 
   392 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   393 von Oheimb;
   394 
   395 * HOL/IMPP: extension of IMP with local variables and mutually
   396 recursive procedures, by David von Oheimb;
   397 
   398 * HOL/Lambda: converted into new-style theory and document;
   399 
   400 * HOL/ex/Multiquote: example of multiple nested quotations and
   401 anti-quotations -- basically a generalized version of de-Bruijn
   402 representation; very useful in avoiding lifting of operations;
   403 
   404 * HOL/record: added general record equality rule to simpset; fixed
   405 select-update simplification procedure to handle extended records as
   406 well; admit "r" as field name;
   407 
   408 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   409 other numeric types and also as the identity of groups, rings, etc.;
   410 
   411 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   412 Types nat and int belong to this axclass;
   413 
   414 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   415    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   416    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   417   two terms #m*u and #n*u are replaced by #(m+n)*u
   418     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   419   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   420     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   421 
   422 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   423 powerful prover for predicate logic but knows nothing of clasets; see
   424 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   425 
   426 * HOL: new version of "case_tac" subsumes both boolean case split and
   427 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   428 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   429 
   430 * HOL: simplification no longer dives into case-expressions: only the
   431 selector expression is simplified, but not the remaining arms; to
   432 enable full simplification of case-expressions for datatype t, you may
   433 remove t.weak_case_cong from the simpset, either globally (Delcongs
   434 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   435 
   436 * HOL/recdef: the recursion equations generated by 'recdef' for
   437 function 'f' are now called f.simps instead of f.rules; if all
   438 termination conditions are proved automatically, these simplification
   439 rules are added to the simpset, as in primrec; rules may be named
   440 individually as well, resulting in a separate list of theorems for
   441 each equation;
   442 
   443 * HOL/While is a new theory that provides a while-combinator. It
   444 permits the definition of tail-recursive functions without the
   445 provision of a termination measure. The latter is necessary once the
   446 invariant proof rule for while is applied.
   447 
   448 * HOL: new (overloaded) notation for the set of elements below/above
   449 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   450 
   451 * HOL: theorems impI, allI, ballI bound as "strip";
   452 
   453 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   454 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   455 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   456 
   457 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   458 
   459 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   460 main HOL, but was unused);
   461 
   462 * HOL: fewer consts declared as global (e.g. have to refer to
   463 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   464 
   465 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   466 in case of overlap with user translations (e.g. judgements over
   467 tuples); (note that the underlying logical represenation is still
   468 bogus);
   469 
   470 
   471 *** ZF ***
   472 
   473 * ZF: simplification automatically cancels common terms in arithmetic
   474 expressions over nat and int;
   475 
   476 * ZF: new treatment of nat to minimize type-checking: all operators
   477 coerce their operands to a natural number using the function natify,
   478 making the algebraic laws unconditional;
   479 
   480 * ZF: as above, for int: operators coerce their operands to an integer
   481 using the function intify;
   482 
   483 * ZF: the integer library now contains many of the usual laws for the
   484 orderings, including $<=, and monotonicity laws for $+ and $*;
   485 
   486 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   487 simplification;
   488 
   489 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   490 to the simplifier and classical reasoner simultaneously;
   491 
   492 
   493 *** General ***
   494 
   495 * Provers: blast_tac now handles actual object-logic rules as
   496 assumptions; note that auto_tac uses blast_tac internally as well;
   497 
   498 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   499 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   500 
   501 * Provers: delrules now handles destruct rules as well (no longer need
   502 explicit make_elim);
   503 
   504 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   505   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   506 use instead the strong form,
   507   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   508 in HOL, FOL and ZF the function cla_make_elim will create such rules
   509 from destruct-rules;
   510 
   511 * Provers: Simplifier.easy_setup provides a fast path to basic
   512 Simplifier setup for new object-logics;
   513 
   514 * Pure: AST translation rules no longer require constant head on LHS;
   515 
   516 * Pure: improved name spaces: ambiguous output is qualified; support
   517 for hiding of names;
   518 
   519 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   520 XSYMBOL_HOME; no longer need to do manual configuration in most
   521 situations;
   522 
   523 * system: compression of ML heaps images may now be controlled via -c
   524 option of isabelle and isatool usedir (currently only observed by
   525 Poly/ML);
   526 
   527 * system: isatool installfonts may handle X-Symbol fonts as well (very
   528 useful for remote X11);
   529 
   530 * system: provide TAGS file for Isabelle sources;
   531 
   532 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   533 order;
   534 
   535 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   536 timing flag supersedes proof_timing and Toplevel.trace;
   537 
   538 * ML: new combinators |>> and |>>> for incremental transformations
   539 with secondary results (e.g. certain theory extensions):
   540 
   541 * ML: PureThy.add_defs gets additional argument to indicate potential
   542 overloading (usually false);
   543 
   544 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   545 results;
   546 
   547 
   548 
   549 New in Isabelle99 (October 1999)
   550 --------------------------------
   551 
   552 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   553 
   554 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   555 are no longer simplified.  (This allows the simplifier to unfold recursive
   556 functional programs.)  To restore the old behaviour, declare
   557 
   558     Delcongs [if_weak_cong];
   559 
   560 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   561 complement;
   562 
   563 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   564 
   565 * HOL/datatype: mutual_induct_tac no longer exists --
   566   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   567 
   568 * HOL/typedef: fixed type inference for representing set; type
   569 arguments now have to occur explicitly on the rhs as type constraints;
   570 
   571 * ZF: The con_defs part of an inductive definition may no longer refer
   572 to constants declared in the same theory;
   573 
   574 * HOL, ZF: the function mk_cases, generated by the inductive
   575 definition package, has lost an argument.  To simplify its result, it
   576 uses the default simpset instead of a supplied list of theorems.
   577 
   578 * HOL/List: the constructors of type list are now Nil and Cons;
   579 
   580 * Simplifier: the type of the infix ML functions
   581         setSSolver addSSolver setSolver addSolver
   582 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   583 for packaging solvers. A solver is created via
   584         mk_solver: string -> (thm list -> int -> tactic) -> solver
   585 where the string argument is only a comment.
   586 
   587 
   588 *** Proof tools ***
   589 
   590 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   591 decision procedure for linear arithmetic. Currently it is used for
   592 types `nat', `int', and `real' in HOL (see below); it can, should and
   593 will be instantiated for other types and logics as well.
   594 
   595 * The simplifier now accepts rewrite rules with flexible heads, eg
   596      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   597   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   598   matching.
   599 
   600 
   601 *** General ***
   602 
   603 * New Isabelle/Isar subsystem provides an alternative to traditional
   604 tactical theorem proving; together with the ProofGeneral/isar user
   605 interface it offers an interactive environment for developing human
   606 readable proof documents (Isar == Intelligible semi-automated
   607 reasoning); for further information see isatool doc isar-ref,
   608 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   609 
   610 * improved and simplified presentation of theories: better HTML markup
   611 (including colors), graph views in several sizes; isatool usedir now
   612 provides a proper interface for user theories (via -P option); actual
   613 document preparation based on (PDF)LaTeX is available as well (for
   614 new-style theories only); see isatool doc system for more information;
   615 
   616 * native support for Proof General, both for classic Isabelle and
   617 Isabelle/Isar;
   618 
   619 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   620 using the graph browser tool;
   621 
   622 * Isabelle manuals now also available as PDF;
   623 
   624 * theory loader rewritten from scratch (may not be fully
   625 bug-compatible); old loadpath variable has been replaced by show_path,
   626 add_path, del_path, reset_path functions; new operations such as
   627 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   628 isatool doc ref);
   629 
   630 * improved isatool install: option -k creates KDE application icon,
   631 option -p DIR installs standalone binaries;
   632 
   633 * added ML_PLATFORM setting (useful for cross-platform installations);
   634 more robust handling of platform specific ML images for SML/NJ;
   635 
   636 * the settings environment is now statically scoped, i.e. it is never
   637 created again in sub-processes invoked from isabelle, isatool, or
   638 Isabelle;
   639 
   640 * path element specification '~~' refers to '$ISABELLE_HOME';
   641 
   642 * in locales, the "assumes" and "defines" parts may be omitted if
   643 empty;
   644 
   645 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   646 long arrows);
   647 
   648 * new print_mode "HTML";
   649 
   650 * new flag show_tags controls display of tags of theorems (which are
   651 basically just comments that may be attached by some tools);
   652 
   653 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   654 mode and goal output format:
   655 
   656 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   657 244c244
   658 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   659 ---
   660 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   661 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   662 181c181
   663 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   664 ---
   665 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   666 
   667 * function bind_thms stores lists of theorems (cf. bind_thm);
   668 
   669 * new shorthand tactics ftac, eatac, datac, fatac;
   670 
   671 * qed (and friends) now accept "" as result name; in that case the
   672 theorem is not stored, but proper checks and presentation of the
   673 result still apply;
   674 
   675 * theorem database now also indexes constants "Trueprop", "all",
   676 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   677 
   678 
   679 *** HOL ***
   680 
   681 ** HOL arithmetic **
   682 
   683 * There are now decision procedures for linear arithmetic over nat and
   684 int:
   685 
   686 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   687 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   688 are treated as atomic; subformulae not involving type `nat' or `int'
   689 are ignored; quantified subformulae are ignored unless they are
   690 positive universal or negative existential. The tactic has to be
   691 invoked by hand and can be a little bit slow. In particular, the
   692 running time is exponential in the number of occurrences of `min' and
   693 `max', and `-' on `nat'.
   694 
   695 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   696 (negated) (in)equalities among the premises and the conclusion into
   697 account (i.e. no compound formulae) and does not know about `min' and
   698 `max', and `-' on `nat'. It is fast and is used automatically by the
   699 simplifier.
   700 
   701 NB: At the moment, these decision procedures do not cope with mixed
   702 nat/int formulae where the two parts interact, such as `m < n ==>
   703 int(m) < int(n)'.
   704 
   705 * HOL/Numeral provides a generic theory of numerals (encoded
   706 efficiently as bit strings); setup for types nat/int/real is in place;
   707 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   708 int, existing theories and proof scripts may require a few additional
   709 type constraints;
   710 
   711 * integer division and remainder can now be performed on constant
   712 arguments;
   713 
   714 * many properties of integer multiplication, division and remainder
   715 are now available;
   716 
   717 * An interface to the Stanford Validity Checker (SVC) is available through the
   718 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   719 are proved automatically.  SVC must be installed separately, and its results
   720 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   721 invocation of the underlying oracle).  For SVC see
   722   http://verify.stanford.edu/SVC
   723 
   724 * IsaMakefile: the HOL-Real target now builds an actual image;
   725 
   726 
   727 ** HOL misc **
   728 
   729 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   730 (in Isabelle/Isar) -- by Gertrud Bauer;
   731 
   732 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   733 analysis for assembly languages with subtypes;
   734 
   735 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   736 -- avoids syntactic ambiguities and treats state, transition, and
   737 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   738 changed syntax and (many) tactics;
   739 
   740 * HOL/inductive: Now also handles more general introduction rules such
   741   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   742   theorems are now maintained within the theory (maintained via the
   743   "mono" attribute);
   744 
   745 * HOL/datatype: Now also handles arbitrarily branching datatypes
   746   (using function types) such as
   747 
   748   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   749 
   750 * HOL/record: record_simproc (part of the default simpset) takes care
   751 of selectors applied to updated records; record_split_tac is no longer
   752 part of the default claset; update_defs may now be removed from the
   753 simpset in many cases; COMPATIBILITY: old behavior achieved by
   754 
   755   claset_ref () := claset() addSWrapper record_split_wrapper;
   756   Delsimprocs [record_simproc]
   757 
   758 * HOL/typedef: fixed type inference for representing set; type
   759 arguments now have to occur explicitly on the rhs as type constraints;
   760 
   761 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   762 names rather than an ML expression;
   763 
   764 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   765 supplied later.  Program schemes can be defined, such as
   766     "While B C s = (if B s then While B C (C s) else s)"
   767 where the well-founded relation can be chosen after B and C have been given.
   768 
   769 * HOL/List: the constructors of type list are now Nil and Cons;
   770 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   771 course, ML tools referring to List.list.op # etc. have to be adapted;
   772 
   773 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   774 disabled by default; run isabelle with option -m HOL to get back to
   775 the original Gordon/HOL-style output;
   776 
   777 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   778 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   779 
   780 * HOL basic syntax simplified (more orthogonal): all variants of
   781 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   782 Eps operator is provided as well: "SOME x. P[x]";
   783 
   784 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   785 
   786 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   787 thus available for user theories;
   788 
   789 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   790 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   791 time;
   792 
   793 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   794 several times and then mp;
   795 
   796 
   797 *** LK ***
   798 
   799 * the notation <<...>> is now available as a notation for sequences of
   800 formulas;
   801 
   802 * the simplifier is now installed
   803 
   804 * the axiom system has been generalized (thanks to Soren Heilmann)
   805 
   806 * the classical reasoner now has a default rule database
   807 
   808 
   809 *** ZF ***
   810 
   811 * new primrec section allows primitive recursive functions to be given
   812 directly (as in HOL) over datatypes and the natural numbers;
   813 
   814 * new tactics induct_tac and exhaust_tac for induction (or case
   815 analysis) over datatypes and the natural numbers;
   816 
   817 * the datatype declaration of type T now defines the recursor T_rec;
   818 
   819 * simplification automatically does freeness reasoning for datatype
   820 constructors;
   821 
   822 * automatic type-inference, with AddTCs command to insert new
   823 type-checking rules;
   824 
   825 * datatype introduction rules are now added as Safe Introduction rules
   826 to the claset;
   827 
   828 * the syntax "if P then x else y" is now available in addition to
   829 if(P,x,y);
   830 
   831 
   832 *** Internal programming interfaces ***
   833 
   834 * tuned simplifier trace output; new flag debug_simp;
   835 
   836 * structures Vartab / Termtab (instances of TableFun) offer efficient
   837 tables indexed by indexname_ord / term_ord (compatible with aconv);
   838 
   839 * AxClass.axclass_tac lost the theory argument;
   840 
   841 * tuned current_goals_markers semantics: begin / end goal avoids
   842 printing empty lines;
   843 
   844 * removed prs and prs_fn hook, which was broken because it did not
   845 include \n in its semantics, forcing writeln to add one
   846 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   847 string -> unit if you really want to output text without newline;
   848 
   849 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   850 plain output, interface builders may have to enable 'isabelle_font'
   851 mode to get Isabelle font glyphs as before;
   852 
   853 * refined token_translation interface; INCOMPATIBILITY: output length
   854 now of type real instead of int;
   855 
   856 * theory loader actions may be traced via new ThyInfo.add_hook
   857 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   858 your own database of information attached to *whole* theories -- as
   859 opposed to intra-theory data slots offered via TheoryDataFun;
   860 
   861 * proper handling of dangling sort hypotheses (at last!);
   862 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   863 extra sort hypotheses that can be witnessed from the type signature;
   864 the force_strip_shyps flag is gone, any remaining shyps are simply
   865 left in the theorem (with a warning issued by strip_shyps_warning);
   866 
   867 
   868 
   869 New in Isabelle98-1 (October 1998)
   870 ----------------------------------
   871 
   872 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   873 
   874 * several changes of automated proof tools;
   875 
   876 * HOL: major changes to the inductive and datatype packages, including
   877 some minor incompatibilities of theory syntax;
   878 
   879 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   880 called `inj_on';
   881 
   882 * HOL: removed duplicate thms in Arith:
   883   less_imp_add_less  should be replaced by  trans_less_add1
   884   le_imp_add_le      should be replaced by  trans_le_add1
   885 
   886 * HOL: unary minus is now overloaded (new type constraints may be
   887 required);
   888 
   889 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   890 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   891 now taken as an integer constant.
   892 
   893 * Pure: ML function 'theory_of' renamed to 'theory';
   894 
   895 
   896 *** Proof tools ***
   897 
   898 * Simplifier:
   899   1. Asm_full_simp_tac is now more aggressive.
   900      1. It will sometimes reorient premises if that increases their power to
   901         simplify.
   902      2. It does no longer proceed strictly from left to right but may also
   903         rotate premises to achieve further simplification.
   904      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   905      old Asm_full_simp_tac in that it does not rotate premises.
   906   2. The simplifier now knows a little bit about nat-arithmetic.
   907 
   908 * Classical reasoner: wrapper mechanism for the classical reasoner now
   909 allows for selected deletion of wrappers, by introduction of names for
   910 wrapper functionals.  This implies that addbefore, addSbefore,
   911 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   912 and that adding two tactics with the same name overwrites the first
   913 one (emitting a warning).
   914   type wrapper = (int -> tactic) -> (int -> tactic)
   915   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   916   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   917   delWrapper, delSWrapper: claset *  string            -> claset
   918   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   919 
   920 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   921 semantics; addbefore now affects only the unsafe part of step_tac
   922 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   923 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   924 by Force_tac;
   925 
   926 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   927 compWrapper; added safe wrapper (and access functions for it);
   928 
   929 * HOL/split_all_tac is now much faster and fails if there is nothing
   930 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   931 and the names of the automatically generated variables have changed.
   932 split_all_tac has moved within claset() from unsafe wrappers to safe
   933 wrappers, which means that !!-bound variables are split much more
   934 aggressively, and safe_tac and clarify_tac now split such variables.
   935 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   936 Note: the same holds for record_split_tac, which does the job of
   937 split_all_tac for record fields.
   938 
   939 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   940 permanently to the default simpset using Addsplits just like
   941 Addsimps. They can be removed via Delsplits just like
   942 Delsimps. Lower-case versions are also available.
   943 
   944 * HOL/Simplifier: The rule split_if is now part of the default
   945 simpset. This means that the simplifier will eliminate all occurrences
   946 of if-then-else in the conclusion of a goal. To prevent this, you can
   947 either remove split_if completely from the default simpset by
   948 `Delsplits [split_if]' or remove it in a specific call of the
   949 simplifier using `... delsplits [split_if]'.  You can also add/delete
   950 other case splitting rules to/from the default simpset: every datatype
   951 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   952 t is the name of the datatype).
   953 
   954 * Classical reasoner / Simplifier combination: new force_tac (and
   955 derivatives Force_tac, force) combines rewriting and classical
   956 reasoning (and whatever other tools) similarly to auto_tac, but is
   957 aimed to solve the given subgoal completely.
   958 
   959 
   960 *** General ***
   961 
   962 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   963 and `goalw': the theory is no longer needed as an explicit argument -
   964 the current theory context is used; assumptions are no longer returned
   965 at the ML-level unless one of them starts with ==> or !!; it is
   966 recommended to convert to these new commands using isatool fixgoal
   967 (backup your sources first!);
   968 
   969 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   970 the current theory context, and 'theory' to lookup stored theories;
   971 
   972 * new theory section 'locale' for declaring constants, assumptions and
   973 definitions that have local scope;
   974 
   975 * new theory section 'nonterminals' for purely syntactic types;
   976 
   977 * new theory section 'setup' for generic ML setup functions
   978 (e.g. package initialization);
   979 
   980 * the distribution now includes Isabelle icons: see
   981 lib/logo/isabelle-{small,tiny}.xpm;
   982 
   983 * isatool install - install binaries with absolute references to
   984 ISABELLE_HOME/bin;
   985 
   986 * isatool logo -- create instances of the Isabelle logo (as EPS);
   987 
   988 * print mode 'emacs' reserved for Isamode;
   989 
   990 * support multiple print (ast) translations per constant name;
   991 
   992 * theorems involving oracles are now printed with a suffixed [!];
   993 
   994 
   995 *** HOL ***
   996 
   997 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   998 
   999 * HOL/inductive package reorganized and improved: now supports mutual
  1000 definitions such as
  1001 
  1002   inductive EVEN ODD
  1003     intrs
  1004       null "0 : EVEN"
  1005       oddI "n : EVEN ==> Suc n : ODD"
  1006       evenI "n : ODD ==> Suc n : EVEN"
  1007 
  1008 new theorem list "elims" contains an elimination rule for each of the
  1009 recursive sets; inductive definitions now handle disjunctive premises
  1010 correctly (also ZF);
  1011 
  1012 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1013 "mutual_induct" no longer exists - the induction rule is always
  1014 contained in "induct";
  1015 
  1016 
  1017 * HOL/datatype package re-implemented and greatly improved: now
  1018 supports mutually recursive datatypes such as
  1019 
  1020   datatype
  1021     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1022             | SUM ('a aexp) ('a aexp)
  1023             | DIFF ('a aexp) ('a aexp)
  1024             | NUM 'a
  1025   and
  1026     'a bexp = LESS ('a aexp) ('a aexp)
  1027             | AND ('a bexp) ('a bexp)
  1028             | OR ('a bexp) ('a bexp)
  1029 
  1030 as well as indirectly recursive datatypes such as
  1031 
  1032   datatype
  1033     ('a, 'b) term = Var 'a
  1034                   | App 'b ((('a, 'b) term) list)
  1035 
  1036 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1037 induction on mutually / indirectly recursive datatypes.
  1038 
  1039 Primrec equations are now stored in theory and can be accessed via
  1040 <function_name>.simps.
  1041 
  1042 INCOMPATIBILITIES:
  1043 
  1044   - Theories using datatypes must now have theory Datatype as an
  1045     ancestor.
  1046   - The specific <typename>.induct_tac no longer exists - use the
  1047     generic induct_tac instead.
  1048   - natE has been renamed to nat.exhaust - use exhaust_tac
  1049     instead of res_inst_tac ... natE. Note that the variable
  1050     names in nat.exhaust differ from the names in natE, this
  1051     may cause some "fragile" proofs to fail.
  1052   - The theorems split_<typename>_case and split_<typename>_case_asm
  1053     have been renamed to <typename>.split and <typename>.split_asm.
  1054   - Since default sorts of type variables are now handled correctly,
  1055     some datatype definitions may have to be annotated with explicit
  1056     sort constraints.
  1057   - Primrec definitions no longer require function name and type
  1058     of recursive argument.
  1059 
  1060 Consider using isatool fixdatatype to adapt your theories and proof
  1061 scripts to the new package (backup your sources first!).
  1062 
  1063 
  1064 * HOL/record package: considerably improved implementation; now
  1065 includes concrete syntax for record types, terms, updates; theorems
  1066 for surjective pairing and splitting !!-bound record variables; proof
  1067 support is as follows:
  1068 
  1069   1) standard conversions (selectors or updates applied to record
  1070 constructor terms) are part of the standard simpset;
  1071 
  1072   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1073 made part of standard simpset and claset via addIffs;
  1074 
  1075   3) a tactic for record field splitting (record_split_tac) is part of
  1076 the standard claset (addSWrapper);
  1077 
  1078 To get a better idea about these rules you may retrieve them via
  1079 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1080 the name of your record type.
  1081 
  1082 The split tactic 3) conceptually simplifies by the following rule:
  1083 
  1084   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1085 
  1086 Thus any record variable that is bound by meta-all will automatically
  1087 blow up into some record constructor term, consequently the
  1088 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1089 solve record problems automatically.
  1090 
  1091 
  1092 * reorganized the main HOL image: HOL/Integ and String loaded by
  1093 default; theory Main includes everything;
  1094 
  1095 * automatic simplification of integer sums and comparisons, using cancellation;
  1096 
  1097 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1098 
  1099 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1100 
  1101 * many new identities for unions, intersections, set difference, etc.;
  1102 
  1103 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1104 called split_if, split_split, split_sum_case and split_nat_case (to go
  1105 with add/delsplits);
  1106 
  1107 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1108 (?x::unit) = (); this is made part of the default simpset, which COULD
  1109 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1110 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1111 unit_abs_eta_conv is added in order to counter the effect of
  1112 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1113 %u.f();
  1114 
  1115 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1116 makes more sense);
  1117 
  1118 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1119   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1120   disjointness reasoning but breaking a few old proofs.
  1121 
  1122 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1123 to 'converse' from 'inverse' (for compatibility with ZF and some
  1124 literature);
  1125 
  1126 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1127 the well-founded relation;
  1128 
  1129 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1130     Compl A.  The "Compl" syntax remains available as input syntax for this
  1131     release ONLY.
  1132 
  1133 * HOL/Update: new theory of function updates:
  1134     f(a:=b) == %x. if x=a then b else f x
  1135 may also be iterated as in f(a:=b,c:=d,...);
  1136 
  1137 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1138 
  1139 * HOL/List:
  1140   - new function list_update written xs[i:=v] that updates the i-th
  1141     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1142   - new function `upt' written [i..j(] which generates the list
  1143     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1144     bound write [i..j], which is a shorthand for [i..j+1(].
  1145   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1146 
  1147 * HOL/Arith:
  1148   - removed 'pred' (predecessor) function;
  1149   - generalized some theorems about n-1;
  1150   - many new laws about "div" and "mod";
  1151   - new laws about greatest common divisors (see theory ex/Primes);
  1152 
  1153 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1154 instead of "inverse";
  1155 
  1156 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1157   of the multiset ordering;
  1158 
  1159 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1160   (not included by default);
  1161 
  1162 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1163 
  1164 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1165   programs, i.e. different program variables may have different types.
  1166 
  1167 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1168   [previously, this check worked only if the rewrite rule was unconditional]
  1169   Now rew can involve either definitions or equalities (either == or =).
  1170 
  1171 
  1172 *** ZF ***
  1173 
  1174 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1175   only the theorems proved on ZF.ML;
  1176 
  1177 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1178   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1179   disjointness reasoning but breaking a few old proofs.
  1180 
  1181 * ZF/Update: new theory of function updates
  1182     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1183   may also be iterated as in f(a:=b,c:=d,...);
  1184 
  1185 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1186 
  1187 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1188   [previously, this check worked only if the rewrite rule was unconditional]
  1189   Now rew can involve either definitions or equalities (either == or =).
  1190 
  1191 * case_tac provided for compatibility with HOL
  1192     (like the old excluded_middle_tac, but with subgoals swapped)
  1193 
  1194 
  1195 *** Internal programming interfaces ***
  1196 
  1197 * Pure: several new basic modules made available for general use, see
  1198 also src/Pure/README;
  1199 
  1200 * improved the theory data mechanism to support encapsulation (data
  1201 kind name replaced by private Object.kind, acting as authorization
  1202 key); new type-safe user interface via functor TheoryDataFun; generic
  1203 print_data function becomes basically useless;
  1204 
  1205 * removed global_names compatibility flag -- all theory declarations
  1206 are qualified by default;
  1207 
  1208 * module Pure/Syntax now offers quote / antiquote translation
  1209 functions (useful for Hoare logic etc. with implicit dependencies);
  1210 see HOL/ex/Antiquote for an example use;
  1211 
  1212 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1213 cterm -> thm;
  1214 
  1215 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1216 subgoal;
  1217 
  1218 * Display.print_goals function moved to Locale.print_goals;
  1219 
  1220 * standard print function for goals supports current_goals_markers
  1221 variable for marking begin of proof, end of proof, start of goal; the
  1222 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1223 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1224 for example;
  1225 
  1226 
  1227 
  1228 New in Isabelle98 (January 1998)
  1229 --------------------------------
  1230 
  1231 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1232 
  1233 * changed lexical syntax of terms / types: dots made part of long
  1234 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1235 
  1236 * simpset (and claset) reference variable replaced by functions
  1237 simpset / simpset_ref;
  1238 
  1239 * no longer supports theory aliases (via merge) and non-trivial
  1240 implicit merge of thms' signatures;
  1241 
  1242 * most internal names of constants changed due to qualified names;
  1243 
  1244 * changed Pure/Sequence interface (see Pure/seq.ML);
  1245 
  1246 
  1247 *** General Changes ***
  1248 
  1249 * hierachically structured name spaces (for consts, types, axms, thms
  1250 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1251 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1252 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1253 long_names for fully qualified output names; NOTE: ML programs
  1254 (special tactics, packages etc.) referring to internal names may have
  1255 to be adapted to cope with fully qualified names; in case of severe
  1256 backward campatibility problems try setting 'global_names' at compile
  1257 time to have enrything declared within a flat name space; one may also
  1258 fine tune name declarations in theories via the 'global' and 'local'
  1259 section;
  1260 
  1261 * reimplemented the implicit simpset and claset using the new anytype
  1262 data filed in signatures; references simpset:simpset ref etc. are
  1263 replaced by functions simpset:unit->simpset and
  1264 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1265 to patch your ML files accordingly;
  1266 
  1267 * HTML output now includes theory graph data for display with Java
  1268 applet or isatool browser; data generated automatically via isatool
  1269 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1270 
  1271 * defs may now be conditional; improved rewrite_goals_tac to handle
  1272 conditional equations;
  1273 
  1274 * defs now admits additional type arguments, using TYPE('a) syntax;
  1275 
  1276 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1277 creates a new theory node; implicit merge of thms' signatures is
  1278 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1279 transfer:theory->thm->thm in (rare) cases;
  1280 
  1281 * improved handling of draft signatures / theories; draft thms (and
  1282 ctyps, cterms) are automatically promoted to real ones;
  1283 
  1284 * slightly changed interfaces for oracles: admit many per theory, named
  1285 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1286 
  1287 * print_goals: optional output of const types (set show_consts and
  1288 show_types);
  1289 
  1290 * improved output of warnings (###) and errors (***);
  1291 
  1292 * subgoal_tac displays a warning if the new subgoal has type variables;
  1293 
  1294 * removed old README and Makefiles;
  1295 
  1296 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1297 
  1298 * removed obsolete init_pps and init_database;
  1299 
  1300 * deleted the obsolete tactical STATE, which was declared by
  1301     fun STATE tacfun st = tacfun st st;
  1302 
  1303 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1304 (which abbreviates $HOME);
  1305 
  1306 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1307 use isatool fixseq to adapt your ML programs (this works for fully
  1308 qualified references to the Sequence structure only!);
  1309 
  1310 * use_thy no longer requires writable current directory; it always
  1311 reloads .ML *and* .thy file, if either one is out of date;
  1312 
  1313 
  1314 *** Classical Reasoner ***
  1315 
  1316 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1317 tactics that use classical reasoning to simplify a subgoal without
  1318 splitting it into several subgoals;
  1319 
  1320 * Safe_tac: like safe_tac but uses the default claset;
  1321 
  1322 
  1323 *** Simplifier ***
  1324 
  1325 * added simplification meta rules:
  1326     (asm_)(full_)simplify: simpset -> thm -> thm;
  1327 
  1328 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1329 logics (again);
  1330 
  1331 * added prems argument to simplification procedures;
  1332 
  1333 * HOL, FOL, ZF: added infix function `addsplits':
  1334   instead of `<simpset> setloop (split_tac <thms>)'
  1335   you can simply write `<simpset> addsplits <thms>'
  1336 
  1337 
  1338 *** Syntax ***
  1339 
  1340 * TYPE('a) syntax for type reflection terms;
  1341 
  1342 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1343 
  1344 * pretty printer: changed order of mixfix annotation preference (again!);
  1345 
  1346 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1347 
  1348 
  1349 *** HOL ***
  1350 
  1351 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1352   with `addloop' of the simplifier to faciliate case splitting in premises.
  1353 
  1354 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1355 
  1356 * HOL/Auth: new protocol proofs including some for the Internet
  1357   protocol TLS;
  1358 
  1359 * HOL/Map: new theory of `maps' a la VDM;
  1360 
  1361 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1362 cancelling out common nat summands from =, <, <= (in)equalities, or
  1363 differences; simplification procedures nat_cancel_factor for
  1364 cancelling common factor from =, <, <= (in)equalities over natural
  1365 sums; nat_cancel contains both kinds of procedures, it is installed by
  1366 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1367 
  1368 * HOL/simplifier: terms of the form
  1369   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1370   are rewritten to
  1371   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1372   and those of the form
  1373   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1374   are rewritten to
  1375   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1376 
  1377 * HOL/datatype
  1378   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1379 
  1380   P(t_case f1 ... fn x) =
  1381      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1382         ...
  1383        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1384      )
  1385 
  1386   and a theorem `split_t_case_asm' of the form
  1387 
  1388   P(t_case f1 ... fn x) =
  1389     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1390         ...
  1391        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1392      )
  1393   which can be added to a simpset via `addsplits'. The existing theorems
  1394   expand_list_case and expand_option_case have been renamed to
  1395   split_list_case and split_option_case.
  1396 
  1397 * HOL/Arithmetic:
  1398   - `pred n' is automatically converted to `n-1'.
  1399     Users are strongly encouraged not to use `pred' any longer,
  1400     because it will disappear altogether at some point.
  1401   - Users are strongly encouraged to write "0 < n" rather than
  1402     "n ~= 0". Theorems and proof tools have been modified towards this
  1403     `standard'.
  1404 
  1405 * HOL/Lists:
  1406   the function "set_of_list" has been renamed "set" (and its theorems too);
  1407   the function "nth" now takes its arguments in the reverse order and
  1408   has acquired the infix notation "!" as in "xs!n".
  1409 
  1410 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1411 
  1412 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1413   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1414 
  1415 * HOL/record: extensible records with schematic structural subtyping
  1416 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1417 still lacks various theorems and concrete record syntax;
  1418 
  1419 
  1420 *** HOLCF ***
  1421 
  1422 * removed "axioms" and "generated by" sections;
  1423 
  1424 * replaced "ops" section by extended "consts" section, which is capable of
  1425   handling the continuous function space "->" directly;
  1426 
  1427 * domain package:
  1428   . proves theorems immediately and stores them in the theory,
  1429   . creates hierachical name space,
  1430   . now uses normal mixfix annotations (instead of cinfix...),
  1431   . minor changes to some names and values (for consistency),
  1432   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1433   . separator between mutual domain defs: changed "," to "and",
  1434   . improved handling of sort constraints;  now they have to
  1435     appear on the left-hand side of the equations only;
  1436 
  1437 * fixed LAM <x,y,zs>.b syntax;
  1438 
  1439 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1440 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1441 
  1442 
  1443 *** FOL and ZF ***
  1444 
  1445 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1446   with `addloop' of the simplifier to faciliate case splitting in premises.
  1447 
  1448 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1449 in HOL, they strip ALL and --> from proved theorems;
  1450 
  1451 
  1452 
  1453 New in Isabelle94-8 (May 1997)
  1454 ------------------------------
  1455 
  1456 *** General Changes ***
  1457 
  1458 * new utilities to build / run / maintain Isabelle etc. (in parts
  1459 still somewhat experimental); old Makefiles etc. still functional;
  1460 
  1461 * new 'Isabelle System Manual';
  1462 
  1463 * INSTALL text, together with ./configure and ./build scripts;
  1464 
  1465 * reimplemented type inference for greater efficiency, better error
  1466 messages and clean internal interface;
  1467 
  1468 * prlim command for dealing with lots of subgoals (an easier way of
  1469 setting goals_limit);
  1470 
  1471 
  1472 *** Syntax ***
  1473 
  1474 * supports alternative (named) syntax tables (parser and pretty
  1475 printer); internal interface is provided by add_modesyntax(_i);
  1476 
  1477 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1478 be used in conjunction with the Isabelle symbol font; uses the
  1479 "symbols" syntax table;
  1480 
  1481 * added token_translation interface (may translate name tokens in
  1482 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1483 the current print_mode); IMPORTANT: user print translation functions
  1484 are responsible for marking newly introduced bounds
  1485 (Syntax.mark_boundT);
  1486 
  1487 * token translations for modes "xterm" and "xterm_color" that display
  1488 names in bold, underline etc. or colors (which requires a color
  1489 version of xterm);
  1490 
  1491 * infixes may now be declared with names independent of their syntax;
  1492 
  1493 * added typed_print_translation (like print_translation, but may
  1494 access type of constant);
  1495 
  1496 
  1497 *** Classical Reasoner ***
  1498 
  1499 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1500 some limitations.  Blast_tac...
  1501   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1502   + ignores elimination rules that don't have the correct format
  1503         (the conclusion MUST be a formula variable)
  1504   + ignores types, which can make HOL proofs fail
  1505   + rules must not require higher-order unification, e.g. apply_type in ZF
  1506     [message "Function Var's argument not a bound variable" relates to this]
  1507   + its proof strategy is more general but can actually be slower
  1508 
  1509 * substitution with equality assumptions no longer permutes other
  1510 assumptions;
  1511 
  1512 * minor changes in semantics of addafter (now called addaltern); renamed
  1513 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1514 (and access functions for it);
  1515 
  1516 * improved combination of classical reasoner and simplifier:
  1517   + functions for handling clasimpsets
  1518   + improvement of addss: now the simplifier is called _after_ the
  1519     safe steps.
  1520   + safe variant of addss called addSss: uses safe simplifications
  1521     _during_ the safe steps. It is more complete as it allows multiple
  1522     instantiations of unknowns (e.g. with slow_tac).
  1523 
  1524 *** Simplifier ***
  1525 
  1526 * added interface for simplification procedures (functions that
  1527 produce *proven* rewrite rules on the fly, depending on current
  1528 redex);
  1529 
  1530 * ordering on terms as parameter (used for ordered rewriting);
  1531 
  1532 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1533 
  1534 * the solver is now split into a safe and an unsafe part.
  1535 This should be invisible for the normal user, except that the
  1536 functions setsolver and addsolver have been renamed to setSolver and
  1537 addSolver; added safe_asm_full_simp_tac;
  1538 
  1539 
  1540 *** HOL ***
  1541 
  1542 * a generic induction tactic `induct_tac' which works for all datatypes and
  1543 also for type `nat';
  1544 
  1545 * a generic case distinction tactic `exhaust_tac' which works for all
  1546 datatypes and also for type `nat';
  1547 
  1548 * each datatype comes with a function `size';
  1549 
  1550 * patterns in case expressions allow tuple patterns as arguments to
  1551 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1552 
  1553 * primrec now also works with type nat;
  1554 
  1555 * recdef: a new declaration form, allows general recursive functions to be
  1556 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1557 
  1558 * the constant for negation has been renamed from "not" to "Not" to
  1559 harmonize with FOL, ZF, LK, etc.;
  1560 
  1561 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1562 infinite lists;
  1563 
  1564 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1565 
  1566 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1567 problems in commutative rings, using axiomatic type classes for + and *;
  1568 
  1569 * more examples in HOL/MiniML and HOL/Auth;
  1570 
  1571 * more default rewrite rules for quantifiers, union/intersection;
  1572 
  1573 * a new constant `arbitrary == @x.False';
  1574 
  1575 * HOLCF/IOA replaces old HOL/IOA;
  1576 
  1577 * HOLCF changes: derived all rules and arities
  1578   + axiomatic type classes instead of classes
  1579   + typedef instead of faking type definitions
  1580   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1581   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1582   + eliminated the types void, one, tr
  1583   + use unit lift and bool lift (with translations) instead of one and tr
  1584   + eliminated blift from Lift3.thy (use Def instead of blift)
  1585   all eliminated rules are derived as theorems --> no visible changes ;
  1586 
  1587 
  1588 *** ZF ***
  1589 
  1590 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1591 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1592 as ZF_cs addSIs [equalityI];
  1593 
  1594 
  1595 
  1596 New in Isabelle94-7 (November 96)
  1597 ---------------------------------
  1598 
  1599 * allowing negative levels (as offsets) in prlev and choplev;
  1600 
  1601 * super-linear speedup for large simplifications;
  1602 
  1603 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1604 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1605 FAIL); can suppress it using the command Delsimps (ex_simps @
  1606 all_simps); De Morgan laws are also now included, by default;
  1607 
  1608 * improved printing of ==>  :  ~:
  1609 
  1610 * new object-logic "Sequents" adds linear logic, while replacing LK
  1611 and Modal (thanks to Sara Kalvala);
  1612 
  1613 * HOL/Auth: correctness proofs for authentication protocols;
  1614 
  1615 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1616 examples on HOL/Auth);
  1617 
  1618 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1619 the rewriter and classical reasoner simultaneously;
  1620 
  1621 * function uresult no longer returns theorems in "standard" format;
  1622 regain previous version by: val uresult = standard o uresult;
  1623 
  1624 
  1625 
  1626 New in Isabelle94-6
  1627 -------------------
  1628 
  1629 * oracles -- these establish an interface between Isabelle and trusted
  1630 external reasoners, which may deliver results as theorems;
  1631 
  1632 * proof objects (in particular record all uses of oracles);
  1633 
  1634 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1635 
  1636 * "constdefs" section in theory files;
  1637 
  1638 * "primrec" section (HOL) no longer requires names;
  1639 
  1640 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1641 
  1642 
  1643 
  1644 New in Isabelle94-5
  1645 -------------------
  1646 
  1647 * reduced space requirements;
  1648 
  1649 * automatic HTML generation from theories;
  1650 
  1651 * theory files no longer require "..." (quotes) around most types;
  1652 
  1653 * new examples, including two proofs of the Church-Rosser theorem;
  1654 
  1655 * non-curried (1994) version of HOL is no longer distributed;
  1656 
  1657 
  1658 
  1659 New in Isabelle94-4
  1660 -------------------
  1661 
  1662 * greatly reduced space requirements;
  1663 
  1664 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1665 
  1666 * searchable theorem database (see the section "Retrieving theorems" on
  1667 page 8 of the Reference Manual);
  1668 
  1669 * new examples, including Grabczewski's monumental case study of the
  1670 Axiom of Choice;
  1671 
  1672 * The previous version of HOL renamed to Old_HOL;
  1673 
  1674 * The new version of HOL (previously called CHOL) uses a curried syntax
  1675 for functions.  Application looks like f a b instead of f(a,b);
  1676 
  1677 * Mutually recursive inductive definitions finally work in HOL;
  1678 
  1679 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1680 translates to the operator "split";
  1681 
  1682 
  1683 
  1684 New in Isabelle94-3
  1685 -------------------
  1686 
  1687 * new infix operator, addss, allowing the classical reasoner to
  1688 perform simplification at each step of its search.  Example:
  1689         fast_tac (cs addss ss)
  1690 
  1691 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1692 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1693 look like (a,b) instead of <a,b>;
  1694 
  1695 * PLEASE NOTE: CHOL will eventually replace HOL!
  1696 
  1697 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1698 It translates to the operator "split".  A new theory of integers is available;
  1699 
  1700 * In ZF, integer numerals now denote two's-complement binary integers.
  1701 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1702 
  1703 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1704 of the Axiom of Choice;
  1705 
  1706 
  1707 
  1708 New in Isabelle94-2
  1709 -------------------
  1710 
  1711 * Significantly faster resolution;
  1712 
  1713 * the different sections in a .thy file can now be mixed and repeated
  1714 freely;
  1715 
  1716 * Database of theorems for FOL, HOL and ZF.  New
  1717 commands including qed, qed_goal and bind_thm store theorems in the database.
  1718 
  1719 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1720 a given theory (thms_of), or find out what theory a theorem was proved in
  1721 (theory_of_thm);
  1722 
  1723 * Bugs fixed in the inductive definition and datatype packages;
  1724 
  1725 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1726 and HOL_dup_cs obsolete;
  1727 
  1728 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1729 have been removed;
  1730 
  1731 * Simpler definition of function space in ZF;
  1732 
  1733 * new results about cardinal and ordinal arithmetic in ZF;
  1734 
  1735 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1736 types;
  1737 
  1738 
  1739 $Id$