NEWS
author wenzelm
Tue Jan 30 14:21:50 2001 +0100 (2001-01-30)
changeset 10998 fece8333adfc
parent 10976 0e7cf6f9fa29
child 11016 8f8ba41a5e7a
permissions -rw-r--r--
tuned;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 *** Overview of INCOMPATIBILITIES ***
     6 
     7 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
     8 gfp_Tarski to gfp_unfold;
     9 
    10 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
    11 
    12 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
    13 relation); infix "^^" has been renamed "``"; infix "``" has been
    14 renamed "`"; "univalent" has been renamed "single_valued";
    15 
    16 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
    17 operation;
    18 
    19 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
    20 
    21 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
    22 
    23 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
    24 consequence, it is no longer monotonic wrt. the local goal context
    25 (which is now passed through the inductive cases);
    26 
    27 * Document preparation: renamed standard symbols \<ll> to \<lless> and
    28 \<gg> to \<ggreater>;
    29 
    30 
    31 *** Document preparation ***
    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 * improved isabelle style files; more abstract symbol implementation
    46 (should now use \isamath{...} and \isatext{...} in custom symbol
    47 definitions);
    48 
    49 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
    50 state; Note that presentation of goal states does not conform to
    51 actual human-readable proof documents.  Please do not include goal
    52 states into document output unless you really know what you are doing!
    53 
    54 * isatool unsymbolize tunes sources for plain ASCII communication;
    55 
    56 
    57 *** Isar ***
    58 
    59 * Pure: Isar now suffers initial goal statements to contain unbound
    60 schematic variables (this does not conform to actual readable proof
    61 documents, due to unpredictable outcome and non-compositional proof
    62 checking); users who know what they are doing may use schematic goals
    63 for Prolog-style synthesis of proven results;
    64 
    65 * Pure: assumption method (an implicit finishing) now handles actual
    66 rules as well;
    67 
    68 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
    69 initial goal, declare "that" only as Pure intro (only for single
    70 steps); the "that" rule assumption may now be involved in implicit
    71 finishing, thus ".." becomes a feasible for trivial obtains;
    72 
    73 * Pure: default proof step now includes 'intro_classes'; thus trivial
    74 instance proofs may be performed by "..";
    75 
    76 * Pure: ?thesis / ?this / "..." now work for pure meta-level
    77 statements as well;
    78 
    79 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
    80 rule (as well as the assumption rule);
    81 
    82 * Pure: 'thm_deps' command visualizes dependencies of theorems and
    83 lemmas, using the graph browser tool;
    84 
    85 * Pure: predict failure of "show" in interactive mode;
    86 
    87 * HOL: improved method 'induct' --- now handles non-atomic goals
    88 (potential INCOMPATIBILITY); tuned error handling;
    89 
    90 * HOL: cases and induct rules now provide explicit hints about the
    91 number of facts to be consumed (0 for "type" and 1 for "set" rules);
    92 any remaining facts are inserted into the goal verbatim;
    93 
    94 * HOL: local contexts (aka cases) may now contain term bindings as
    95 well; the 'cases' and 'induct' methods new provide a ?case binding for
    96 the result to be shown in each case;
    97 
    98 * HOL: added 'recdef_tc' command;
    99 
   100 
   101 *** HOL ***
   102 
   103 * HOL/Library: a collection of generic theories to be used together
   104 with main HOL; the theory loader path already includes this directory
   105 by default; the following existing theories have been moved here:
   106 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   107 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   108 
   109 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   110 modelling and verification task performed in Isabelle/HOL +
   111 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   112 
   113 * HOL basics: added overloaded operations "inverse" and "divide"
   114 (infix "/"), syntax for generic "abs" operation, generic summation
   115 operator;
   116 
   117 * HOL/typedef: simplified package, provide more useful rules (see also
   118 HOL/subset.thy);
   119 
   120 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   121 now expressed as a proper nested rule (old-style tactic scripts may
   122 require atomize_strip_tac to cope with non-atomic premises);
   123 
   124 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   125 to "split_conv" (old name still available for compatibility);
   126 
   127 * HOL: improved concrete syntax for strings (e.g. allows translation
   128 rules with string literals);
   129 
   130 * HOL-Hyperreal: a new target, extending HOL-Real with the hyperreals
   131 and Fleuriot's mechanization of analysis;
   132 
   133 * HOL-Real, HOL-Hyperreals: improved arithmetic simplification;
   134 
   135 
   136 *** CTT ***
   137 
   138 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   139 "lam" is displayed as TWO lambda-symbols
   140 
   141 * CTT: theory Main now available, containing everything (that is, Bool
   142 and Arith);
   143 
   144 
   145 *** General ***
   146 
   147 * print modes "brackets" and "no_brackets" control output of nested =>
   148 (types) and ==> (props); the default behaviour is "brackets";
   149 
   150 * system: support Poly/ML 4.0 (current beta versions);
   151 
   152 * Pure: the Simplifier has been implemented properly as a derived rule
   153 outside of the actual kernel (at last!); the overall performance
   154 penalty in practical applications is about 50%, while reliability of
   155 the Isabelle inference kernel has been greatly improved;
   156 
   157 * Provers: fast_tac (and friends) now handle actual object-logic rules
   158 as assumptions as well;
   159 
   160 
   161 
   162 New in Isabelle99-1 (October 2000)
   163 ----------------------------------
   164 
   165 *** Overview of INCOMPATIBILITIES ***
   166 
   167 * HOL: simplification of natural numbers is much changed; to partly
   168 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   169 issue the following ML commands:
   170 
   171   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   172   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   173 
   174 * HOL: simplification no longer dives into case-expressions; this is
   175 controlled by "t.weak_case_cong" for each datatype t;
   176 
   177 * HOL: nat_less_induct renamed to less_induct;
   178 
   179 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   180 fixsome to patch .thy and .ML sources automatically;
   181 
   182   select_equality  -> some_equality
   183   select_eq_Ex     -> some_eq_ex
   184   selectI2EX       -> someI2_ex
   185   selectI2         -> someI2
   186   selectI          -> someI
   187   select1_equality -> some1_equality
   188   Eps_sym_eq       -> some_sym_eq_trivial
   189   Eps_eq           -> some_eq_trivial
   190 
   191 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   192 
   193 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   194 instead);
   195 
   196 * HOL: the recursion equations generated by 'recdef' are now called
   197 f.simps instead of f.rules;
   198 
   199 * HOL: qed_spec_mp now also handles bounded ALL as well;
   200 
   201 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   202 sometimes be needed;
   203 
   204 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   205 
   206 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   207 
   208 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   209 product is now "<*>" instead of "Times"; the lexicographic product is
   210 now "<*lex*>" instead of "**";
   211 
   212 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   213 of main HOL, but was unused); better use HOL's datatype package;
   214 
   215 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   216 the old syntax may be recovered as follows:
   217 
   218   syntax (symbols)
   219     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   220       (infixl "\\<oplus>" 100)
   221 
   222 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   223 
   224 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   225 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   226 internally;
   227 
   228 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   229 changed from A/r to A//r;
   230 
   231 * ZF: new treatment of arithmetic (nat & int) may break some old
   232 proofs;
   233 
   234 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   235 rulify -> rule_format, elimify -> elim_format, ...);
   236 
   237 * Isar/Provers: intro/elim/dest attributes changed; renamed
   238 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   239 should have to change intro!! to intro? only); replaced "delrule" by
   240 "rule del";
   241 
   242 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   243 
   244 * Provers: strengthened force_tac by using new first_best_tac;
   245 
   246 * LaTeX document preparation: several changes of isabelle.sty (see
   247 lib/texinputs);
   248 
   249 
   250 *** Document preparation ***
   251 
   252 * formal comments (text blocks etc.) in new-style theories may now
   253 contain antiquotations of thm/prop/term/typ/text to be presented
   254 according to latex print mode; concrete syntax is like this:
   255 @{term[show_types] "f(x) = a + x"};
   256 
   257 * isatool mkdir provides easy setup of Isabelle session directories,
   258 including proper document sources;
   259 
   260 * generated LaTeX sources are now deleted after successful run
   261 (isatool document -c); may retain a copy somewhere else via -D option
   262 of isatool usedir;
   263 
   264 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   265 style files, achieving self-contained LaTeX sources and simplifying
   266 LaTeX debugging;
   267 
   268 * old-style theories now produce (crude) LaTeX output as well;
   269 
   270 * browser info session directories are now self-contained (may be put
   271 on WWW server seperately); improved graphs of nested sessions; removed
   272 graph for 'all sessions';
   273 
   274 * several improvements in isabelle style files; \isabellestyle{it}
   275 produces fake math mode output; \isamarkupheader is now \section by
   276 default; see lib/texinputs/isabelle.sty etc.;
   277 
   278 
   279 *** Isar ***
   280 
   281 * Isar/Pure: local results and corresponding term bindings are now
   282 subject to Hindley-Milner polymorphism (similar to ML); this
   283 accommodates incremental type-inference very nicely;
   284 
   285 * Isar/Pure: new derived language element 'obtain' supports
   286 generalized existence reasoning;
   287 
   288 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   289 support accumulation of results, without applying any rules yet;
   290 useful to collect intermediate results without explicit name
   291 references, and for use with transitivity rules with more than 2
   292 premises;
   293 
   294 * Isar/Pure: scalable support for case-analysis type proofs: new
   295 'case' language element refers to local contexts symbolically, as
   296 produced by certain proof methods; internally, case names are attached
   297 to theorems as "tags";
   298 
   299 * Isar/Pure: theory command 'hide' removes declarations from
   300 class/type/const name spaces;
   301 
   302 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   303 indicate potential overloading;
   304 
   305 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   306 
   307 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   308 "{a,b,c}" instead of {a,b,c};
   309 
   310 * Isar/Pure now provides its own version of intro/elim/dest
   311 attributes; useful for building new logics, but beware of confusion
   312 with the version in Provers/classical;
   313 
   314 * Isar/Pure: the local context of (non-atomic) goals is provided via
   315 case name 'antecedent';
   316 
   317 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   318 to the current context is now done automatically);
   319 
   320 * Isar/Pure: theory command 'method_setup' provides a simple interface
   321 for definining proof methods in ML;
   322 
   323 * Isar/Provers: intro/elim/dest attributes changed; renamed
   324 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   325 most cases, one should have to change intro!! to intro? only);
   326 replaced "delrule" by "rule del";
   327 
   328 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   329 'symmetric' attribute (the latter supercedes [RS sym]);
   330 
   331 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   332 method modifier); 'simp' method: 'only:' modifier removes loopers as
   333 well (including splits);
   334 
   335 * Isar/Provers: Simplifier and Classical methods now support all kind
   336 of modifiers used in the past, including 'cong', 'iff', etc.
   337 
   338 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   339 of Simplifier and Classical reasoner);
   340 
   341 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   342 now support named cases; major packages (inductive, datatype, primrec,
   343 recdef) support case names and properly name parameters;
   344 
   345 * Isar/HOL: new transitivity rules for substitution in inequalities --
   346 monotonicity conditions are extracted to be proven at end of
   347 calculations;
   348 
   349 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   350 method anyway;
   351 
   352 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   353 split_if split_if_asm; datatype package provides theorems foo.splits =
   354 foo.split foo.split_asm for each datatype;
   355 
   356 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   357 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   358 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   359 use "(cases (simplified))" method in proper proof texts);
   360 
   361 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   362 
   363 * Isar: names of theorems etc. may be natural numbers as well;
   364 
   365 * Isar: 'pr' command: optional arguments for goals_limit and
   366 ProofContext.prems_limit; no longer prints theory contexts, but only
   367 proof states;
   368 
   369 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   370 additional print modes to be specified; e.g. "pr(latex)" will print
   371 proof state according to the Isabelle LaTeX style;
   372 
   373 * Isar: improved support for emulating tactic scripts, including proof
   374 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   375 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   376 (for HOL datatypes);
   377 
   378 * Isar: simplified (more robust) goal selection of proof methods: 1st
   379 goal, all goals, or explicit goal specifier (tactic emulation); thus
   380 'proof method scripts' have to be in depth-first order;
   381 
   382 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   383 
   384 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   385 should instead use individual commands for printing items
   386 (print_commands, print_methods etc.);
   387 
   388 * Isar: added 'nothing' --- the empty list of theorems;
   389 
   390 
   391 *** HOL ***
   392 
   393 * HOL/MicroJava: formalization of a fragment of Java, together with a
   394 corresponding virtual machine and a specification of its bytecode
   395 verifier and a lightweight bytecode verifier, including proofs of
   396 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   397 Cornelia Pusch (see also the homepage of project Bali at
   398 http://isabelle.in.tum.de/Bali/);
   399 
   400 * HOL/Algebra: new theory of rings and univariate polynomials, by
   401 Clemens Ballarin;
   402 
   403 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   404 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   405 Rasmussen;
   406 
   407 * HOL/Lattice: fundamental concepts of lattice theory and order
   408 structures, including duals, properties of bounds versus algebraic
   409 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   410 Theorem for complete lattices etc.; may also serve as a demonstration
   411 for abstract algebraic reasoning using axiomatic type classes, and
   412 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   413 
   414 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   415 von Oheimb;
   416 
   417 * HOL/IMPP: extension of IMP with local variables and mutually
   418 recursive procedures, by David von Oheimb;
   419 
   420 * HOL/Lambda: converted into new-style theory and document;
   421 
   422 * HOL/ex/Multiquote: example of multiple nested quotations and
   423 anti-quotations -- basically a generalized version of de-Bruijn
   424 representation; very useful in avoiding lifting of operations;
   425 
   426 * HOL/record: added general record equality rule to simpset; fixed
   427 select-update simplification procedure to handle extended records as
   428 well; admit "r" as field name;
   429 
   430 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   431 other numeric types and also as the identity of groups, rings, etc.;
   432 
   433 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   434 Types nat and int belong to this axclass;
   435 
   436 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   437    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   438    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   439   two terms #m*u and #n*u are replaced by #(m+n)*u
   440     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   441   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   442     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   443 
   444 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   445 powerful prover for predicate logic but knows nothing of clasets; see
   446 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   447 
   448 * HOL: new version of "case_tac" subsumes both boolean case split and
   449 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   450 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   451 
   452 * HOL: simplification no longer dives into case-expressions: only the
   453 selector expression is simplified, but not the remaining arms; to
   454 enable full simplification of case-expressions for datatype t, you may
   455 remove t.weak_case_cong from the simpset, either globally (Delcongs
   456 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   457 
   458 * HOL/recdef: the recursion equations generated by 'recdef' for
   459 function 'f' are now called f.simps instead of f.rules; if all
   460 termination conditions are proved automatically, these simplification
   461 rules are added to the simpset, as in primrec; rules may be named
   462 individually as well, resulting in a separate list of theorems for
   463 each equation;
   464 
   465 * HOL/While is a new theory that provides a while-combinator. It
   466 permits the definition of tail-recursive functions without the
   467 provision of a termination measure. The latter is necessary once the
   468 invariant proof rule for while is applied.
   469 
   470 * HOL: new (overloaded) notation for the set of elements below/above
   471 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   472 
   473 * HOL: theorems impI, allI, ballI bound as "strip";
   474 
   475 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   476 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   477 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   478 
   479 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   480 
   481 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   482 main HOL, but was unused);
   483 
   484 * HOL: fewer consts declared as global (e.g. have to refer to
   485 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   486 
   487 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   488 in case of overlap with user translations (e.g. judgements over
   489 tuples); (note that the underlying logical represenation is still
   490 bogus);
   491 
   492 
   493 *** ZF ***
   494 
   495 * ZF: simplification automatically cancels common terms in arithmetic
   496 expressions over nat and int;
   497 
   498 * ZF: new treatment of nat to minimize type-checking: all operators
   499 coerce their operands to a natural number using the function natify,
   500 making the algebraic laws unconditional;
   501 
   502 * ZF: as above, for int: operators coerce their operands to an integer
   503 using the function intify;
   504 
   505 * ZF: the integer library now contains many of the usual laws for the
   506 orderings, including $<=, and monotonicity laws for $+ and $*;
   507 
   508 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   509 simplification;
   510 
   511 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   512 to the simplifier and classical reasoner simultaneously;
   513 
   514 
   515 *** General ***
   516 
   517 * Provers: blast_tac now handles actual object-logic rules as
   518 assumptions; note that auto_tac uses blast_tac internally as well;
   519 
   520 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   521 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   522 
   523 * Provers: delrules now handles destruct rules as well (no longer need
   524 explicit make_elim);
   525 
   526 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   527   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   528 use instead the strong form,
   529   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   530 in HOL, FOL and ZF the function cla_make_elim will create such rules
   531 from destruct-rules;
   532 
   533 * Provers: Simplifier.easy_setup provides a fast path to basic
   534 Simplifier setup for new object-logics;
   535 
   536 * Pure: AST translation rules no longer require constant head on LHS;
   537 
   538 * Pure: improved name spaces: ambiguous output is qualified; support
   539 for hiding of names;
   540 
   541 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   542 XSYMBOL_HOME; no longer need to do manual configuration in most
   543 situations;
   544 
   545 * system: compression of ML heaps images may now be controlled via -c
   546 option of isabelle and isatool usedir (currently only observed by
   547 Poly/ML);
   548 
   549 * system: isatool installfonts may handle X-Symbol fonts as well (very
   550 useful for remote X11);
   551 
   552 * system: provide TAGS file for Isabelle sources;
   553 
   554 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   555 order;
   556 
   557 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   558 timing flag supersedes proof_timing and Toplevel.trace;
   559 
   560 * ML: new combinators |>> and |>>> for incremental transformations
   561 with secondary results (e.g. certain theory extensions):
   562 
   563 * ML: PureThy.add_defs gets additional argument to indicate potential
   564 overloading (usually false);
   565 
   566 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   567 results;
   568 
   569 
   570 
   571 New in Isabelle99 (October 1999)
   572 --------------------------------
   573 
   574 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   575 
   576 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   577 are no longer simplified.  (This allows the simplifier to unfold recursive
   578 functional programs.)  To restore the old behaviour, declare
   579 
   580     Delcongs [if_weak_cong];
   581 
   582 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   583 complement;
   584 
   585 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   586 
   587 * HOL/datatype: mutual_induct_tac no longer exists --
   588   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   589 
   590 * HOL/typedef: fixed type inference for representing set; type
   591 arguments now have to occur explicitly on the rhs as type constraints;
   592 
   593 * ZF: The con_defs part of an inductive definition may no longer refer
   594 to constants declared in the same theory;
   595 
   596 * HOL, ZF: the function mk_cases, generated by the inductive
   597 definition package, has lost an argument.  To simplify its result, it
   598 uses the default simpset instead of a supplied list of theorems.
   599 
   600 * HOL/List: the constructors of type list are now Nil and Cons;
   601 
   602 * Simplifier: the type of the infix ML functions
   603         setSSolver addSSolver setSolver addSolver
   604 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   605 for packaging solvers. A solver is created via
   606         mk_solver: string -> (thm list -> int -> tactic) -> solver
   607 where the string argument is only a comment.
   608 
   609 
   610 *** Proof tools ***
   611 
   612 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   613 decision procedure for linear arithmetic. Currently it is used for
   614 types `nat', `int', and `real' in HOL (see below); it can, should and
   615 will be instantiated for other types and logics as well.
   616 
   617 * The simplifier now accepts rewrite rules with flexible heads, eg
   618      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   619   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   620   matching.
   621 
   622 
   623 *** General ***
   624 
   625 * New Isabelle/Isar subsystem provides an alternative to traditional
   626 tactical theorem proving; together with the ProofGeneral/isar user
   627 interface it offers an interactive environment for developing human
   628 readable proof documents (Isar == Intelligible semi-automated
   629 reasoning); for further information see isatool doc isar-ref,
   630 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   631 
   632 * improved and simplified presentation of theories: better HTML markup
   633 (including colors), graph views in several sizes; isatool usedir now
   634 provides a proper interface for user theories (via -P option); actual
   635 document preparation based on (PDF)LaTeX is available as well (for
   636 new-style theories only); see isatool doc system for more information;
   637 
   638 * native support for Proof General, both for classic Isabelle and
   639 Isabelle/Isar;
   640 
   641 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   642 using the graph browser tool;
   643 
   644 * Isabelle manuals now also available as PDF;
   645 
   646 * theory loader rewritten from scratch (may not be fully
   647 bug-compatible); old loadpath variable has been replaced by show_path,
   648 add_path, del_path, reset_path functions; new operations such as
   649 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   650 isatool doc ref);
   651 
   652 * improved isatool install: option -k creates KDE application icon,
   653 option -p DIR installs standalone binaries;
   654 
   655 * added ML_PLATFORM setting (useful for cross-platform installations);
   656 more robust handling of platform specific ML images for SML/NJ;
   657 
   658 * the settings environment is now statically scoped, i.e. it is never
   659 created again in sub-processes invoked from isabelle, isatool, or
   660 Isabelle;
   661 
   662 * path element specification '~~' refers to '$ISABELLE_HOME';
   663 
   664 * in locales, the "assumes" and "defines" parts may be omitted if
   665 empty;
   666 
   667 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   668 long arrows);
   669 
   670 * new print_mode "HTML";
   671 
   672 * new flag show_tags controls display of tags of theorems (which are
   673 basically just comments that may be attached by some tools);
   674 
   675 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   676 mode and goal output format:
   677 
   678 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   679 244c244
   680 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   681 ---
   682 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   683 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   684 181c181
   685 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   686 ---
   687 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   688 
   689 * function bind_thms stores lists of theorems (cf. bind_thm);
   690 
   691 * new shorthand tactics ftac, eatac, datac, fatac;
   692 
   693 * qed (and friends) now accept "" as result name; in that case the
   694 theorem is not stored, but proper checks and presentation of the
   695 result still apply;
   696 
   697 * theorem database now also indexes constants "Trueprop", "all",
   698 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   699 
   700 
   701 *** HOL ***
   702 
   703 ** HOL arithmetic **
   704 
   705 * There are now decision procedures for linear arithmetic over nat and
   706 int:
   707 
   708 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   709 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   710 are treated as atomic; subformulae not involving type `nat' or `int'
   711 are ignored; quantified subformulae are ignored unless they are
   712 positive universal or negative existential. The tactic has to be
   713 invoked by hand and can be a little bit slow. In particular, the
   714 running time is exponential in the number of occurrences of `min' and
   715 `max', and `-' on `nat'.
   716 
   717 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   718 (negated) (in)equalities among the premises and the conclusion into
   719 account (i.e. no compound formulae) and does not know about `min' and
   720 `max', and `-' on `nat'. It is fast and is used automatically by the
   721 simplifier.
   722 
   723 NB: At the moment, these decision procedures do not cope with mixed
   724 nat/int formulae where the two parts interact, such as `m < n ==>
   725 int(m) < int(n)'.
   726 
   727 * HOL/Numeral provides a generic theory of numerals (encoded
   728 efficiently as bit strings); setup for types nat/int/real is in place;
   729 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   730 int, existing theories and proof scripts may require a few additional
   731 type constraints;
   732 
   733 * integer division and remainder can now be performed on constant
   734 arguments;
   735 
   736 * many properties of integer multiplication, division and remainder
   737 are now available;
   738 
   739 * An interface to the Stanford Validity Checker (SVC) is available through the
   740 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   741 are proved automatically.  SVC must be installed separately, and its results
   742 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   743 invocation of the underlying oracle).  For SVC see
   744   http://verify.stanford.edu/SVC
   745 
   746 * IsaMakefile: the HOL-Real target now builds an actual image;
   747 
   748 
   749 ** HOL misc **
   750 
   751 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   752 (in Isabelle/Isar) -- by Gertrud Bauer;
   753 
   754 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   755 analysis for assembly languages with subtypes;
   756 
   757 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   758 -- avoids syntactic ambiguities and treats state, transition, and
   759 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   760 changed syntax and (many) tactics;
   761 
   762 * HOL/inductive: Now also handles more general introduction rules such
   763   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   764   theorems are now maintained within the theory (maintained via the
   765   "mono" attribute);
   766 
   767 * HOL/datatype: Now also handles arbitrarily branching datatypes
   768   (using function types) such as
   769 
   770   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   771 
   772 * HOL/record: record_simproc (part of the default simpset) takes care
   773 of selectors applied to updated records; record_split_tac is no longer
   774 part of the default claset; update_defs may now be removed from the
   775 simpset in many cases; COMPATIBILITY: old behavior achieved by
   776 
   777   claset_ref () := claset() addSWrapper record_split_wrapper;
   778   Delsimprocs [record_simproc]
   779 
   780 * HOL/typedef: fixed type inference for representing set; type
   781 arguments now have to occur explicitly on the rhs as type constraints;
   782 
   783 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   784 names rather than an ML expression;
   785 
   786 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   787 supplied later.  Program schemes can be defined, such as
   788     "While B C s = (if B s then While B C (C s) else s)"
   789 where the well-founded relation can be chosen after B and C have been given.
   790 
   791 * HOL/List: the constructors of type list are now Nil and Cons;
   792 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   793 course, ML tools referring to List.list.op # etc. have to be adapted;
   794 
   795 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   796 disabled by default; run isabelle with option -m HOL to get back to
   797 the original Gordon/HOL-style output;
   798 
   799 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   800 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   801 
   802 * HOL basic syntax simplified (more orthogonal): all variants of
   803 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   804 Eps operator is provided as well: "SOME x. P[x]";
   805 
   806 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   807 
   808 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   809 thus available for user theories;
   810 
   811 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   812 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   813 time;
   814 
   815 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   816 several times and then mp;
   817 
   818 
   819 *** LK ***
   820 
   821 * the notation <<...>> is now available as a notation for sequences of
   822 formulas;
   823 
   824 * the simplifier is now installed
   825 
   826 * the axiom system has been generalized (thanks to Soren Heilmann)
   827 
   828 * the classical reasoner now has a default rule database
   829 
   830 
   831 *** ZF ***
   832 
   833 * new primrec section allows primitive recursive functions to be given
   834 directly (as in HOL) over datatypes and the natural numbers;
   835 
   836 * new tactics induct_tac and exhaust_tac for induction (or case
   837 analysis) over datatypes and the natural numbers;
   838 
   839 * the datatype declaration of type T now defines the recursor T_rec;
   840 
   841 * simplification automatically does freeness reasoning for datatype
   842 constructors;
   843 
   844 * automatic type-inference, with AddTCs command to insert new
   845 type-checking rules;
   846 
   847 * datatype introduction rules are now added as Safe Introduction rules
   848 to the claset;
   849 
   850 * the syntax "if P then x else y" is now available in addition to
   851 if(P,x,y);
   852 
   853 
   854 *** Internal programming interfaces ***
   855 
   856 * tuned simplifier trace output; new flag debug_simp;
   857 
   858 * structures Vartab / Termtab (instances of TableFun) offer efficient
   859 tables indexed by indexname_ord / term_ord (compatible with aconv);
   860 
   861 * AxClass.axclass_tac lost the theory argument;
   862 
   863 * tuned current_goals_markers semantics: begin / end goal avoids
   864 printing empty lines;
   865 
   866 * removed prs and prs_fn hook, which was broken because it did not
   867 include \n in its semantics, forcing writeln to add one
   868 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   869 string -> unit if you really want to output text without newline;
   870 
   871 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   872 plain output, interface builders may have to enable 'isabelle_font'
   873 mode to get Isabelle font glyphs as before;
   874 
   875 * refined token_translation interface; INCOMPATIBILITY: output length
   876 now of type real instead of int;
   877 
   878 * theory loader actions may be traced via new ThyInfo.add_hook
   879 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   880 your own database of information attached to *whole* theories -- as
   881 opposed to intra-theory data slots offered via TheoryDataFun;
   882 
   883 * proper handling of dangling sort hypotheses (at last!);
   884 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   885 extra sort hypotheses that can be witnessed from the type signature;
   886 the force_strip_shyps flag is gone, any remaining shyps are simply
   887 left in the theorem (with a warning issued by strip_shyps_warning);
   888 
   889 
   890 
   891 New in Isabelle98-1 (October 1998)
   892 ----------------------------------
   893 
   894 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   895 
   896 * several changes of automated proof tools;
   897 
   898 * HOL: major changes to the inductive and datatype packages, including
   899 some minor incompatibilities of theory syntax;
   900 
   901 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   902 called `inj_on';
   903 
   904 * HOL: removed duplicate thms in Arith:
   905   less_imp_add_less  should be replaced by  trans_less_add1
   906   le_imp_add_le      should be replaced by  trans_le_add1
   907 
   908 * HOL: unary minus is now overloaded (new type constraints may be
   909 required);
   910 
   911 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   912 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   913 now taken as an integer constant.
   914 
   915 * Pure: ML function 'theory_of' renamed to 'theory';
   916 
   917 
   918 *** Proof tools ***
   919 
   920 * Simplifier:
   921   1. Asm_full_simp_tac is now more aggressive.
   922      1. It will sometimes reorient premises if that increases their power to
   923         simplify.
   924      2. It does no longer proceed strictly from left to right but may also
   925         rotate premises to achieve further simplification.
   926      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   927      old Asm_full_simp_tac in that it does not rotate premises.
   928   2. The simplifier now knows a little bit about nat-arithmetic.
   929 
   930 * Classical reasoner: wrapper mechanism for the classical reasoner now
   931 allows for selected deletion of wrappers, by introduction of names for
   932 wrapper functionals.  This implies that addbefore, addSbefore,
   933 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   934 and that adding two tactics with the same name overwrites the first
   935 one (emitting a warning).
   936   type wrapper = (int -> tactic) -> (int -> tactic)
   937   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   938   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   939   delWrapper, delSWrapper: claset *  string            -> claset
   940   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   941 
   942 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   943 semantics; addbefore now affects only the unsafe part of step_tac
   944 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   945 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   946 by Force_tac;
   947 
   948 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   949 compWrapper; added safe wrapper (and access functions for it);
   950 
   951 * HOL/split_all_tac is now much faster and fails if there is nothing
   952 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   953 and the names of the automatically generated variables have changed.
   954 split_all_tac has moved within claset() from unsafe wrappers to safe
   955 wrappers, which means that !!-bound variables are split much more
   956 aggressively, and safe_tac and clarify_tac now split such variables.
   957 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   958 Note: the same holds for record_split_tac, which does the job of
   959 split_all_tac for record fields.
   960 
   961 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   962 permanently to the default simpset using Addsplits just like
   963 Addsimps. They can be removed via Delsplits just like
   964 Delsimps. Lower-case versions are also available.
   965 
   966 * HOL/Simplifier: The rule split_if is now part of the default
   967 simpset. This means that the simplifier will eliminate all occurrences
   968 of if-then-else in the conclusion of a goal. To prevent this, you can
   969 either remove split_if completely from the default simpset by
   970 `Delsplits [split_if]' or remove it in a specific call of the
   971 simplifier using `... delsplits [split_if]'.  You can also add/delete
   972 other case splitting rules to/from the default simpset: every datatype
   973 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   974 t is the name of the datatype).
   975 
   976 * Classical reasoner / Simplifier combination: new force_tac (and
   977 derivatives Force_tac, force) combines rewriting and classical
   978 reasoning (and whatever other tools) similarly to auto_tac, but is
   979 aimed to solve the given subgoal completely.
   980 
   981 
   982 *** General ***
   983 
   984 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   985 and `goalw': the theory is no longer needed as an explicit argument -
   986 the current theory context is used; assumptions are no longer returned
   987 at the ML-level unless one of them starts with ==> or !!; it is
   988 recommended to convert to these new commands using isatool fixgoal
   989 (backup your sources first!);
   990 
   991 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   992 the current theory context, and 'theory' to lookup stored theories;
   993 
   994 * new theory section 'locale' for declaring constants, assumptions and
   995 definitions that have local scope;
   996 
   997 * new theory section 'nonterminals' for purely syntactic types;
   998 
   999 * new theory section 'setup' for generic ML setup functions
  1000 (e.g. package initialization);
  1001 
  1002 * the distribution now includes Isabelle icons: see
  1003 lib/logo/isabelle-{small,tiny}.xpm;
  1004 
  1005 * isatool install - install binaries with absolute references to
  1006 ISABELLE_HOME/bin;
  1007 
  1008 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1009 
  1010 * print mode 'emacs' reserved for Isamode;
  1011 
  1012 * support multiple print (ast) translations per constant name;
  1013 
  1014 * theorems involving oracles are now printed with a suffixed [!];
  1015 
  1016 
  1017 *** HOL ***
  1018 
  1019 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1020 
  1021 * HOL/inductive package reorganized and improved: now supports mutual
  1022 definitions such as
  1023 
  1024   inductive EVEN ODD
  1025     intrs
  1026       null "0 : EVEN"
  1027       oddI "n : EVEN ==> Suc n : ODD"
  1028       evenI "n : ODD ==> Suc n : EVEN"
  1029 
  1030 new theorem list "elims" contains an elimination rule for each of the
  1031 recursive sets; inductive definitions now handle disjunctive premises
  1032 correctly (also ZF);
  1033 
  1034 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1035 "mutual_induct" no longer exists - the induction rule is always
  1036 contained in "induct";
  1037 
  1038 
  1039 * HOL/datatype package re-implemented and greatly improved: now
  1040 supports mutually recursive datatypes such as
  1041 
  1042   datatype
  1043     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1044             | SUM ('a aexp) ('a aexp)
  1045             | DIFF ('a aexp) ('a aexp)
  1046             | NUM 'a
  1047   and
  1048     'a bexp = LESS ('a aexp) ('a aexp)
  1049             | AND ('a bexp) ('a bexp)
  1050             | OR ('a bexp) ('a bexp)
  1051 
  1052 as well as indirectly recursive datatypes such as
  1053 
  1054   datatype
  1055     ('a, 'b) term = Var 'a
  1056                   | App 'b ((('a, 'b) term) list)
  1057 
  1058 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1059 induction on mutually / indirectly recursive datatypes.
  1060 
  1061 Primrec equations are now stored in theory and can be accessed via
  1062 <function_name>.simps.
  1063 
  1064 INCOMPATIBILITIES:
  1065 
  1066   - Theories using datatypes must now have theory Datatype as an
  1067     ancestor.
  1068   - The specific <typename>.induct_tac no longer exists - use the
  1069     generic induct_tac instead.
  1070   - natE has been renamed to nat.exhaust - use exhaust_tac
  1071     instead of res_inst_tac ... natE. Note that the variable
  1072     names in nat.exhaust differ from the names in natE, this
  1073     may cause some "fragile" proofs to fail.
  1074   - The theorems split_<typename>_case and split_<typename>_case_asm
  1075     have been renamed to <typename>.split and <typename>.split_asm.
  1076   - Since default sorts of type variables are now handled correctly,
  1077     some datatype definitions may have to be annotated with explicit
  1078     sort constraints.
  1079   - Primrec definitions no longer require function name and type
  1080     of recursive argument.
  1081 
  1082 Consider using isatool fixdatatype to adapt your theories and proof
  1083 scripts to the new package (backup your sources first!).
  1084 
  1085 
  1086 * HOL/record package: considerably improved implementation; now
  1087 includes concrete syntax for record types, terms, updates; theorems
  1088 for surjective pairing and splitting !!-bound record variables; proof
  1089 support is as follows:
  1090 
  1091   1) standard conversions (selectors or updates applied to record
  1092 constructor terms) are part of the standard simpset;
  1093 
  1094   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1095 made part of standard simpset and claset via addIffs;
  1096 
  1097   3) a tactic for record field splitting (record_split_tac) is part of
  1098 the standard claset (addSWrapper);
  1099 
  1100 To get a better idea about these rules you may retrieve them via
  1101 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1102 the name of your record type.
  1103 
  1104 The split tactic 3) conceptually simplifies by the following rule:
  1105 
  1106   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1107 
  1108 Thus any record variable that is bound by meta-all will automatically
  1109 blow up into some record constructor term, consequently the
  1110 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1111 solve record problems automatically.
  1112 
  1113 
  1114 * reorganized the main HOL image: HOL/Integ and String loaded by
  1115 default; theory Main includes everything;
  1116 
  1117 * automatic simplification of integer sums and comparisons, using cancellation;
  1118 
  1119 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1120 
  1121 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1122 
  1123 * many new identities for unions, intersections, set difference, etc.;
  1124 
  1125 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1126 called split_if, split_split, split_sum_case and split_nat_case (to go
  1127 with add/delsplits);
  1128 
  1129 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1130 (?x::unit) = (); this is made part of the default simpset, which COULD
  1131 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1132 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1133 unit_abs_eta_conv is added in order to counter the effect of
  1134 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1135 %u.f();
  1136 
  1137 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1138 makes more sense);
  1139 
  1140 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1141   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1142   disjointness reasoning but breaking a few old proofs.
  1143 
  1144 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1145 to 'converse' from 'inverse' (for compatibility with ZF and some
  1146 literature);
  1147 
  1148 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1149 the well-founded relation;
  1150 
  1151 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1152     Compl A.  The "Compl" syntax remains available as input syntax for this
  1153     release ONLY.
  1154 
  1155 * HOL/Update: new theory of function updates:
  1156     f(a:=b) == %x. if x=a then b else f x
  1157 may also be iterated as in f(a:=b,c:=d,...);
  1158 
  1159 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1160 
  1161 * HOL/List:
  1162   - new function list_update written xs[i:=v] that updates the i-th
  1163     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1164   - new function `upt' written [i..j(] which generates the list
  1165     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1166     bound write [i..j], which is a shorthand for [i..j+1(].
  1167   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1168 
  1169 * HOL/Arith:
  1170   - removed 'pred' (predecessor) function;
  1171   - generalized some theorems about n-1;
  1172   - many new laws about "div" and "mod";
  1173   - new laws about greatest common divisors (see theory ex/Primes);
  1174 
  1175 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1176 instead of "inverse";
  1177 
  1178 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1179   of the multiset ordering;
  1180 
  1181 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1182   (not included by default);
  1183 
  1184 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1185 
  1186 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1187   programs, i.e. different program variables may have different types.
  1188 
  1189 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1190   [previously, this check worked only if the rewrite rule was unconditional]
  1191   Now rew can involve either definitions or equalities (either == or =).
  1192 
  1193 
  1194 *** ZF ***
  1195 
  1196 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1197   only the theorems proved on ZF.ML;
  1198 
  1199 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1200   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1201   disjointness reasoning but breaking a few old proofs.
  1202 
  1203 * ZF/Update: new theory of function updates
  1204     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1205   may also be iterated as in f(a:=b,c:=d,...);
  1206 
  1207 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1208 
  1209 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1210   [previously, this check worked only if the rewrite rule was unconditional]
  1211   Now rew can involve either definitions or equalities (either == or =).
  1212 
  1213 * case_tac provided for compatibility with HOL
  1214     (like the old excluded_middle_tac, but with subgoals swapped)
  1215 
  1216 
  1217 *** Internal programming interfaces ***
  1218 
  1219 * Pure: several new basic modules made available for general use, see
  1220 also src/Pure/README;
  1221 
  1222 * improved the theory data mechanism to support encapsulation (data
  1223 kind name replaced by private Object.kind, acting as authorization
  1224 key); new type-safe user interface via functor TheoryDataFun; generic
  1225 print_data function becomes basically useless;
  1226 
  1227 * removed global_names compatibility flag -- all theory declarations
  1228 are qualified by default;
  1229 
  1230 * module Pure/Syntax now offers quote / antiquote translation
  1231 functions (useful for Hoare logic etc. with implicit dependencies);
  1232 see HOL/ex/Antiquote for an example use;
  1233 
  1234 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1235 cterm -> thm;
  1236 
  1237 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1238 subgoal;
  1239 
  1240 * Display.print_goals function moved to Locale.print_goals;
  1241 
  1242 * standard print function for goals supports current_goals_markers
  1243 variable for marking begin of proof, end of proof, start of goal; the
  1244 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1245 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1246 for example;
  1247 
  1248 
  1249 
  1250 New in Isabelle98 (January 1998)
  1251 --------------------------------
  1252 
  1253 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1254 
  1255 * changed lexical syntax of terms / types: dots made part of long
  1256 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1257 
  1258 * simpset (and claset) reference variable replaced by functions
  1259 simpset / simpset_ref;
  1260 
  1261 * no longer supports theory aliases (via merge) and non-trivial
  1262 implicit merge of thms' signatures;
  1263 
  1264 * most internal names of constants changed due to qualified names;
  1265 
  1266 * changed Pure/Sequence interface (see Pure/seq.ML);
  1267 
  1268 
  1269 *** General Changes ***
  1270 
  1271 * hierachically structured name spaces (for consts, types, axms, thms
  1272 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1273 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1274 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1275 long_names for fully qualified output names; NOTE: ML programs
  1276 (special tactics, packages etc.) referring to internal names may have
  1277 to be adapted to cope with fully qualified names; in case of severe
  1278 backward campatibility problems try setting 'global_names' at compile
  1279 time to have enrything declared within a flat name space; one may also
  1280 fine tune name declarations in theories via the 'global' and 'local'
  1281 section;
  1282 
  1283 * reimplemented the implicit simpset and claset using the new anytype
  1284 data filed in signatures; references simpset:simpset ref etc. are
  1285 replaced by functions simpset:unit->simpset and
  1286 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1287 to patch your ML files accordingly;
  1288 
  1289 * HTML output now includes theory graph data for display with Java
  1290 applet or isatool browser; data generated automatically via isatool
  1291 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1292 
  1293 * defs may now be conditional; improved rewrite_goals_tac to handle
  1294 conditional equations;
  1295 
  1296 * defs now admits additional type arguments, using TYPE('a) syntax;
  1297 
  1298 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1299 creates a new theory node; implicit merge of thms' signatures is
  1300 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1301 transfer:theory->thm->thm in (rare) cases;
  1302 
  1303 * improved handling of draft signatures / theories; draft thms (and
  1304 ctyps, cterms) are automatically promoted to real ones;
  1305 
  1306 * slightly changed interfaces for oracles: admit many per theory, named
  1307 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1308 
  1309 * print_goals: optional output of const types (set show_consts and
  1310 show_types);
  1311 
  1312 * improved output of warnings (###) and errors (***);
  1313 
  1314 * subgoal_tac displays a warning if the new subgoal has type variables;
  1315 
  1316 * removed old README and Makefiles;
  1317 
  1318 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1319 
  1320 * removed obsolete init_pps and init_database;
  1321 
  1322 * deleted the obsolete tactical STATE, which was declared by
  1323     fun STATE tacfun st = tacfun st st;
  1324 
  1325 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1326 (which abbreviates $HOME);
  1327 
  1328 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1329 use isatool fixseq to adapt your ML programs (this works for fully
  1330 qualified references to the Sequence structure only!);
  1331 
  1332 * use_thy no longer requires writable current directory; it always
  1333 reloads .ML *and* .thy file, if either one is out of date;
  1334 
  1335 
  1336 *** Classical Reasoner ***
  1337 
  1338 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1339 tactics that use classical reasoning to simplify a subgoal without
  1340 splitting it into several subgoals;
  1341 
  1342 * Safe_tac: like safe_tac but uses the default claset;
  1343 
  1344 
  1345 *** Simplifier ***
  1346 
  1347 * added simplification meta rules:
  1348     (asm_)(full_)simplify: simpset -> thm -> thm;
  1349 
  1350 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1351 logics (again);
  1352 
  1353 * added prems argument to simplification procedures;
  1354 
  1355 * HOL, FOL, ZF: added infix function `addsplits':
  1356   instead of `<simpset> setloop (split_tac <thms>)'
  1357   you can simply write `<simpset> addsplits <thms>'
  1358 
  1359 
  1360 *** Syntax ***
  1361 
  1362 * TYPE('a) syntax for type reflection terms;
  1363 
  1364 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1365 
  1366 * pretty printer: changed order of mixfix annotation preference (again!);
  1367 
  1368 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1369 
  1370 
  1371 *** HOL ***
  1372 
  1373 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1374   with `addloop' of the simplifier to faciliate case splitting in premises.
  1375 
  1376 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1377 
  1378 * HOL/Auth: new protocol proofs including some for the Internet
  1379   protocol TLS;
  1380 
  1381 * HOL/Map: new theory of `maps' a la VDM;
  1382 
  1383 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1384 cancelling out common nat summands from =, <, <= (in)equalities, or
  1385 differences; simplification procedures nat_cancel_factor for
  1386 cancelling common factor from =, <, <= (in)equalities over natural
  1387 sums; nat_cancel contains both kinds of procedures, it is installed by
  1388 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1389 
  1390 * HOL/simplifier: terms of the form
  1391   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1392   are rewritten to
  1393   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1394   and those of the form
  1395   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1396   are rewritten to
  1397   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1398 
  1399 * HOL/datatype
  1400   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1401 
  1402   P(t_case f1 ... fn x) =
  1403      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1404         ...
  1405        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1406      )
  1407 
  1408   and a theorem `split_t_case_asm' of the form
  1409 
  1410   P(t_case f1 ... fn x) =
  1411     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1412         ...
  1413        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1414      )
  1415   which can be added to a simpset via `addsplits'. The existing theorems
  1416   expand_list_case and expand_option_case have been renamed to
  1417   split_list_case and split_option_case.
  1418 
  1419 * HOL/Arithmetic:
  1420   - `pred n' is automatically converted to `n-1'.
  1421     Users are strongly encouraged not to use `pred' any longer,
  1422     because it will disappear altogether at some point.
  1423   - Users are strongly encouraged to write "0 < n" rather than
  1424     "n ~= 0". Theorems and proof tools have been modified towards this
  1425     `standard'.
  1426 
  1427 * HOL/Lists:
  1428   the function "set_of_list" has been renamed "set" (and its theorems too);
  1429   the function "nth" now takes its arguments in the reverse order and
  1430   has acquired the infix notation "!" as in "xs!n".
  1431 
  1432 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1433 
  1434 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1435   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1436 
  1437 * HOL/record: extensible records with schematic structural subtyping
  1438 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1439 still lacks various theorems and concrete record syntax;
  1440 
  1441 
  1442 *** HOLCF ***
  1443 
  1444 * removed "axioms" and "generated by" sections;
  1445 
  1446 * replaced "ops" section by extended "consts" section, which is capable of
  1447   handling the continuous function space "->" directly;
  1448 
  1449 * domain package:
  1450   . proves theorems immediately and stores them in the theory,
  1451   . creates hierachical name space,
  1452   . now uses normal mixfix annotations (instead of cinfix...),
  1453   . minor changes to some names and values (for consistency),
  1454   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1455   . separator between mutual domain defs: changed "," to "and",
  1456   . improved handling of sort constraints;  now they have to
  1457     appear on the left-hand side of the equations only;
  1458 
  1459 * fixed LAM <x,y,zs>.b syntax;
  1460 
  1461 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1462 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1463 
  1464 
  1465 *** FOL and ZF ***
  1466 
  1467 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1468   with `addloop' of the simplifier to faciliate case splitting in premises.
  1469 
  1470 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1471 in HOL, they strip ALL and --> from proved theorems;
  1472 
  1473 
  1474 
  1475 New in Isabelle94-8 (May 1997)
  1476 ------------------------------
  1477 
  1478 *** General Changes ***
  1479 
  1480 * new utilities to build / run / maintain Isabelle etc. (in parts
  1481 still somewhat experimental); old Makefiles etc. still functional;
  1482 
  1483 * new 'Isabelle System Manual';
  1484 
  1485 * INSTALL text, together with ./configure and ./build scripts;
  1486 
  1487 * reimplemented type inference for greater efficiency, better error
  1488 messages and clean internal interface;
  1489 
  1490 * prlim command for dealing with lots of subgoals (an easier way of
  1491 setting goals_limit);
  1492 
  1493 
  1494 *** Syntax ***
  1495 
  1496 * supports alternative (named) syntax tables (parser and pretty
  1497 printer); internal interface is provided by add_modesyntax(_i);
  1498 
  1499 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1500 be used in conjunction with the Isabelle symbol font; uses the
  1501 "symbols" syntax table;
  1502 
  1503 * added token_translation interface (may translate name tokens in
  1504 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1505 the current print_mode); IMPORTANT: user print translation functions
  1506 are responsible for marking newly introduced bounds
  1507 (Syntax.mark_boundT);
  1508 
  1509 * token translations for modes "xterm" and "xterm_color" that display
  1510 names in bold, underline etc. or colors (which requires a color
  1511 version of xterm);
  1512 
  1513 * infixes may now be declared with names independent of their syntax;
  1514 
  1515 * added typed_print_translation (like print_translation, but may
  1516 access type of constant);
  1517 
  1518 
  1519 *** Classical Reasoner ***
  1520 
  1521 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1522 some limitations.  Blast_tac...
  1523   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1524   + ignores elimination rules that don't have the correct format
  1525         (the conclusion MUST be a formula variable)
  1526   + ignores types, which can make HOL proofs fail
  1527   + rules must not require higher-order unification, e.g. apply_type in ZF
  1528     [message "Function Var's argument not a bound variable" relates to this]
  1529   + its proof strategy is more general but can actually be slower
  1530 
  1531 * substitution with equality assumptions no longer permutes other
  1532 assumptions;
  1533 
  1534 * minor changes in semantics of addafter (now called addaltern); renamed
  1535 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1536 (and access functions for it);
  1537 
  1538 * improved combination of classical reasoner and simplifier:
  1539   + functions for handling clasimpsets
  1540   + improvement of addss: now the simplifier is called _after_ the
  1541     safe steps.
  1542   + safe variant of addss called addSss: uses safe simplifications
  1543     _during_ the safe steps. It is more complete as it allows multiple
  1544     instantiations of unknowns (e.g. with slow_tac).
  1545 
  1546 *** Simplifier ***
  1547 
  1548 * added interface for simplification procedures (functions that
  1549 produce *proven* rewrite rules on the fly, depending on current
  1550 redex);
  1551 
  1552 * ordering on terms as parameter (used for ordered rewriting);
  1553 
  1554 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1555 
  1556 * the solver is now split into a safe and an unsafe part.
  1557 This should be invisible for the normal user, except that the
  1558 functions setsolver and addsolver have been renamed to setSolver and
  1559 addSolver; added safe_asm_full_simp_tac;
  1560 
  1561 
  1562 *** HOL ***
  1563 
  1564 * a generic induction tactic `induct_tac' which works for all datatypes and
  1565 also for type `nat';
  1566 
  1567 * a generic case distinction tactic `exhaust_tac' which works for all
  1568 datatypes and also for type `nat';
  1569 
  1570 * each datatype comes with a function `size';
  1571 
  1572 * patterns in case expressions allow tuple patterns as arguments to
  1573 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1574 
  1575 * primrec now also works with type nat;
  1576 
  1577 * recdef: a new declaration form, allows general recursive functions to be
  1578 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1579 
  1580 * the constant for negation has been renamed from "not" to "Not" to
  1581 harmonize with FOL, ZF, LK, etc.;
  1582 
  1583 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1584 infinite lists;
  1585 
  1586 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1587 
  1588 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1589 problems in commutative rings, using axiomatic type classes for + and *;
  1590 
  1591 * more examples in HOL/MiniML and HOL/Auth;
  1592 
  1593 * more default rewrite rules for quantifiers, union/intersection;
  1594 
  1595 * a new constant `arbitrary == @x.False';
  1596 
  1597 * HOLCF/IOA replaces old HOL/IOA;
  1598 
  1599 * HOLCF changes: derived all rules and arities
  1600   + axiomatic type classes instead of classes
  1601   + typedef instead of faking type definitions
  1602   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1603   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1604   + eliminated the types void, one, tr
  1605   + use unit lift and bool lift (with translations) instead of one and tr
  1606   + eliminated blift from Lift3.thy (use Def instead of blift)
  1607   all eliminated rules are derived as theorems --> no visible changes ;
  1608 
  1609 
  1610 *** ZF ***
  1611 
  1612 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1613 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1614 as ZF_cs addSIs [equalityI];
  1615 
  1616 
  1617 
  1618 New in Isabelle94-7 (November 96)
  1619 ---------------------------------
  1620 
  1621 * allowing negative levels (as offsets) in prlev and choplev;
  1622 
  1623 * super-linear speedup for large simplifications;
  1624 
  1625 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1626 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1627 FAIL); can suppress it using the command Delsimps (ex_simps @
  1628 all_simps); De Morgan laws are also now included, by default;
  1629 
  1630 * improved printing of ==>  :  ~:
  1631 
  1632 * new object-logic "Sequents" adds linear logic, while replacing LK
  1633 and Modal (thanks to Sara Kalvala);
  1634 
  1635 * HOL/Auth: correctness proofs for authentication protocols;
  1636 
  1637 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1638 examples on HOL/Auth);
  1639 
  1640 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1641 the rewriter and classical reasoner simultaneously;
  1642 
  1643 * function uresult no longer returns theorems in "standard" format;
  1644 regain previous version by: val uresult = standard o uresult;
  1645 
  1646 
  1647 
  1648 New in Isabelle94-6
  1649 -------------------
  1650 
  1651 * oracles -- these establish an interface between Isabelle and trusted
  1652 external reasoners, which may deliver results as theorems;
  1653 
  1654 * proof objects (in particular record all uses of oracles);
  1655 
  1656 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1657 
  1658 * "constdefs" section in theory files;
  1659 
  1660 * "primrec" section (HOL) no longer requires names;
  1661 
  1662 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1663 
  1664 
  1665 
  1666 New in Isabelle94-5
  1667 -------------------
  1668 
  1669 * reduced space requirements;
  1670 
  1671 * automatic HTML generation from theories;
  1672 
  1673 * theory files no longer require "..." (quotes) around most types;
  1674 
  1675 * new examples, including two proofs of the Church-Rosser theorem;
  1676 
  1677 * non-curried (1994) version of HOL is no longer distributed;
  1678 
  1679 
  1680 
  1681 New in Isabelle94-4
  1682 -------------------
  1683 
  1684 * greatly reduced space requirements;
  1685 
  1686 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1687 
  1688 * searchable theorem database (see the section "Retrieving theorems" on
  1689 page 8 of the Reference Manual);
  1690 
  1691 * new examples, including Grabczewski's monumental case study of the
  1692 Axiom of Choice;
  1693 
  1694 * The previous version of HOL renamed to Old_HOL;
  1695 
  1696 * The new version of HOL (previously called CHOL) uses a curried syntax
  1697 for functions.  Application looks like f a b instead of f(a,b);
  1698 
  1699 * Mutually recursive inductive definitions finally work in HOL;
  1700 
  1701 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1702 translates to the operator "split";
  1703 
  1704 
  1705 
  1706 New in Isabelle94-3
  1707 -------------------
  1708 
  1709 * new infix operator, addss, allowing the classical reasoner to
  1710 perform simplification at each step of its search.  Example:
  1711         fast_tac (cs addss ss)
  1712 
  1713 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1714 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1715 look like (a,b) instead of <a,b>;
  1716 
  1717 * PLEASE NOTE: CHOL will eventually replace HOL!
  1718 
  1719 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1720 It translates to the operator "split".  A new theory of integers is available;
  1721 
  1722 * In ZF, integer numerals now denote two's-complement binary integers.
  1723 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1724 
  1725 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1726 of the Axiom of Choice;
  1727 
  1728 
  1729 
  1730 New in Isabelle94-2
  1731 -------------------
  1732 
  1733 * Significantly faster resolution;
  1734 
  1735 * the different sections in a .thy file can now be mixed and repeated
  1736 freely;
  1737 
  1738 * Database of theorems for FOL, HOL and ZF.  New
  1739 commands including qed, qed_goal and bind_thm store theorems in the database.
  1740 
  1741 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1742 a given theory (thms_of), or find out what theory a theorem was proved in
  1743 (theory_of_thm);
  1744 
  1745 * Bugs fixed in the inductive definition and datatype packages;
  1746 
  1747 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1748 and HOL_dup_cs obsolete;
  1749 
  1750 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1751 have been removed;
  1752 
  1753 * Simpler definition of function space in ZF;
  1754 
  1755 * new results about cardinal and ordinal arithmetic in ZF;
  1756 
  1757 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1758 types;
  1759 
  1760 
  1761 $Id$