NEWS
author wenzelm
Tue Sep 26 17:03:52 2000 +0200 (2000-09-26)
changeset 10080 8fb8c17d1cb5
parent 10065 ddb3a014f721
child 10103 4e446f8cef3e
permissions -rw-r--r--
HOL/MicroJava;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in Isabelle99-1 (September 2000)
     6 ------------------------------------
     7 
     8 *** Overview of INCOMPATIBILITIES ***
     9 
    10 * HOL: simplification of natural numbers is much changed; to partly
    11 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
    12 issue the following ML commands:
    13 
    14   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
    15   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
    16 
    17 * HOL: simplification no longer dives into case-expressions;
    18 
    19 * HOL: nat_less_induct renamed to less_induct;
    20 
    21 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
    22 fixsome to patch .thy and .ML sources automatically;
    23 
    24   select_equality  -> some_equality
    25   select_eq_Ex     -> some_eq_ex
    26   selectI2EX       -> someI2_ex
    27   selectI2         -> someI2
    28   selectI          -> someI
    29   select1_equality -> some1_equality
    30   Eps_sym_eq       -> some_sym_eq_trivial
    31   Eps_eq           -> some_eq_trivial
    32 
    33 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    34 
    35 * HOL: removed obsolete theorem binding expand_if (refer to split_if
    36 instead);
    37 
    38 * HOL: the recursion equations generated by 'recdef' are now called
    39 f.simps instead of f.rules;
    40 
    41 * HOL: qed_spec_mp now also handles bounded ALL as well;
    42 
    43 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
    44 sometimes be needed;
    45 
    46 * HOL: the constant for "f``x" is now "image" rather than "op ``";
    47 
    48 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
    49 
    50 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
    51 product is now "<*>" instead of "Times"; the lexicographic product is
    52 now "<*lex*>" instead of "**";
    53 
    54 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
    55 of main HOL, but was unused); better use HOL's datatype package;
    56 
    57 * HOL/Real: "rabs" replaced by overloaded "abs" function;
    58 
    59 * HOL/ML: even fewer consts are declared as global (see theories Ord,
    60 Lfp, Gfp, WF); this only affects ML packages that refer to const names
    61 internally;
    62 
    63 * HOL and ZF: syntax for quotienting wrt an equivalence relation
    64 changed from A/r to A//r;
    65 
    66 * ZF: new treatment of arithmetic (nat & int) may break some old
    67 proofs;
    68 
    69 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
    70 rulify -> rule_format, elimify -> elim_format, ...);
    71 
    72 * Isar/Provers: intro/elim/dest attributes changed; renamed
    73 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
    74 should have to change intro!! to intro? only); replaced "delrule" by
    75 "rule del";
    76 
    77 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
    78 
    79 * Provers: strengthened force_tac by using new first_best_tac;
    80 
    81 * LaTeX document preparation: several changes of isabelle.sty (see
    82 lib/texinputs);
    83 
    84 
    85 *** Document preparation ***
    86 
    87 * formal comments (text blocks etc.) in new-style theories may now
    88 contain antiquotations of thm/prop/term/typ/text to be presented
    89 according to latex print mode; concrete syntax is like this:
    90 @{term[show_types] "f(x) = a + x"};
    91 
    92 * isatool mkdir provides easy setup of Isabelle session directories,
    93 including proper document sources;
    94 
    95 * generated LaTeX sources are now deleted after successful run
    96 (isatool document -c); may retain a copy somewhere else via -D option
    97 of isatool usedir;
    98 
    99 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   100 style files, achieving self-contained LaTeX sources and simplifying
   101 LaTeX debugging;
   102 
   103 * old-style theories now produce (crude) LaTeX output as well;
   104 
   105 * browser info session directories are now self-contained (may be put
   106 on WWW server seperately); improved graphs of nested sessions; removed
   107 graph for 'all sessions';
   108 
   109 * several improvements in isabelle style files; \isabellestyle{it}
   110 produces fake math mode output; \isamarkupheader is now \section by
   111 default; see lib/texinputs/isabelle.sty etc.;
   112 
   113 
   114 *** Isar ***
   115 
   116 * Isar/Pure: local results and corresponding term bindings are now
   117 subject to Hindley-Milner polymorphism (similar to ML); this
   118 accommodates incremental type-inference very nicely;
   119 
   120 * Isar/Pure: new derived language element 'obtain' supports
   121 generalized existence reasoning;
   122 
   123 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   124 support accumulation of results, without applying any rules yet;
   125 useful to collect intermediate results without explicit name
   126 references, and for use with transitivity rules with more than 2
   127 premises;
   128 
   129 * Isar/Pure: scalable support for case-analysis type proofs: new
   130 'case' language element refers to local contexts symbolically, as
   131 produced by certain proof methods; internally, case names are attached
   132 to theorems as "tags";
   133 
   134 * Isar/Pure: theory command 'hide' removes declarations from
   135 class/type/const name spaces;
   136 
   137 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   138 indicate potential overloading;
   139 
   140 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   141 
   142 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   143 "{a,b,c}" instead of {a,b,c};
   144 
   145 * Isar/Pure now provides its own version of intro/elim/dest
   146 attributes; useful for building new logics, but beware of confusion
   147 with the version in Provers/classical;
   148 
   149 * Isar/Pure: the local context of (non-atomic) goals is provided via
   150 case name 'antecedent';
   151 
   152 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   153 to the current context is now done automatically);
   154 
   155 * Isar/Pure: theory command 'method_setup' provides a simple interface
   156 for definining proof methods in ML;
   157 
   158 * Isar/Provers: intro/elim/dest attributes changed; renamed
   159 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   160 most cases, one should have to change intro!! to intro? only);
   161 replaced "delrule" by "rule del";
   162 
   163 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   164 'symmetric' attribute (the latter supercedes [RS sym]);
   165 
   166 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   167 method modifier); 'simp' method: 'only:' modifier removes loopers as
   168 well (including splits);
   169 
   170 * Isar/Provers: Simplifier and Classical methods now support all kind
   171 of modifiers used in the past, including 'cong', 'iff', etc.
   172 
   173 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   174 of Simplifier and Classical reasoner);
   175 
   176 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   177 now support named cases; major packages (inductive, datatype, primrec,
   178 recdef) support case names and properly name parameters;
   179 
   180 * Isar/HOL: new transitivity rules for substitution in inequalities --
   181 monotonicity conditions are extracted to be proven at end of
   182 calculations;
   183 
   184 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   185 method anyway;
   186 
   187 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   188 split_if split_if_asm; datatype package provides theorems foo.splits =
   189 foo.split foo.split_asm for each datatype;
   190 
   191 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   192 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   193 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   194 use "(cases (simplified))" method in proper proof texts);
   195 
   196 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   197 
   198 * Isar: names of theorems etc. may be natural numbers as well;
   199 
   200 * Isar: 'pr' command: optional arguments for goals_limit and
   201 ProofContext.prems_limit; no longer prints theory contexts, but only
   202 proof states;
   203 
   204 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   205 additional print modes to be specified; e.g. "pr(latex)" will print
   206 proof state according to the Isabelle LaTeX style;
   207 
   208 * Isar: improved support for emulating tactic scripts, including proof
   209 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   210 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   211 (for HOL datatypes);
   212 
   213 * Isar: simplified (more robust) goal selection of proof methods: 1st
   214 goal, all goals, or explicit goal specifier (tactic emulation); thus
   215 'proof method scripts' have to be in depth-first order;
   216 
   217 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   218 
   219 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   220 should instead use individual commands for printing items
   221 (print_commands, print_methods etc.);
   222 
   223 * Isar: added 'nothing' --- the empty list of theorems;
   224 
   225 
   226 *** HOL ***
   227 
   228 * HOL/MicroJava: formalization of a fragment of Java, together with a
   229 corresponding virtual machine and a specification of its bytecode
   230 verifier and a lightweight bytecode verifier, including proofs of
   231 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   232 Cornelia Pusch (see also the homepage of project Bali at
   233 http://isabelle.in.tum.de/Bali/);
   234 
   235 * HOL/Algebra: new theory of rings and univariate polynomials, by
   236 Clemens Ballarin;
   237 
   238 * HOL/NumberTheory: Fundamental Theorem of Arithmetic, Chinese
   239 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   240 Rasmussen;
   241 
   242 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   243 von Oheimb;
   244 
   245 * HOL/Lambda: converted into new-style theory and document;
   246 
   247 * HOL/ex/Multiquote: example of multiple nested quotations and
   248 anti-quotations -- basically a generalized version of de-Bruijn
   249 representation; very useful in avoiding lifting of operations;
   250 
   251 * HOL/record: added general record equality rule to simpset; fixed
   252 select-update simplification procedure to handle extended records as
   253 well; admit "r" as field name;
   254 
   255 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   256 other numeric types and also as the identity of groups, rings, etc.;
   257 
   258 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   259 Types nat and int belong to this axclass;
   260 
   261 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   262    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   263    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   264   two terms #m*u and #n*u are replaced by #(m+n)*u
   265     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   266   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   267     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   268 
   269 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   270 powerful prover for predicate logic but knows nothing of clasets; see
   271 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   272 
   273 * HOL: new version of "case_tac" subsumes both boolean case split and
   274 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   275 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   276 
   277 * HOL: simplification no longer dives into case-expressions: only the
   278 selector expression is simplified, but not the remaining arms. To
   279 enable full simplification of case-expressions for datatype t, you
   280 need to remove t.weak_case_cong from the simpset, either permanently
   281 (Delcongs [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   282 
   283 * HOL/recdef: the recursion equations generated by 'recdef' for
   284 function 'f' are now called f.simps instead of f.rules; if all
   285 termination conditions are proved automatically, these simplification
   286 rules are added to the simpset, as in primrec; rules may be named
   287 individually as well, resulting in a separate list of theorems for
   288 each equation;
   289 
   290 * HOL/While is a new theory that provides a while-combinator. It
   291 permits the definition of tail-recursive functions without the
   292 provision of a termination measure. The latter is necessary once the
   293 invariant proof rule for while is applied.
   294 
   295 * HOL: new (overloaded) notation for the set of elements below/above
   296 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   297 
   298 * HOL: theorems impI, allI, ballI bound as "strip";
   299 
   300 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   301 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   302 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   303 
   304 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   305 
   306 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   307 main HOL, but was unused);
   308 
   309 * HOL: fewer consts declared as global (e.g. have to refer to
   310 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   311 
   312 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   313 in case of overlap with user translations (e.g. judgements over
   314 tuples); (note that the underlying logical represenation is still
   315 bogus);
   316 
   317 
   318 *** ZF ***
   319 
   320 * ZF: simplification automatically cancels common terms in arithmetic
   321 expressions over nat and int;
   322 
   323 * ZF: new treatment of nat to minimize type-checking: all operators
   324 coerce their operands to a natural number using the function natify,
   325 making the algebraic laws unconditional;
   326 
   327 * ZF: as above, for int: operators coerce their operands to an integer
   328 using the function intify;
   329 
   330 * ZF: the integer library now contains many of the usual laws for the
   331 orderings, including $<=, and monotonicity laws for $+ and $*;
   332 
   333 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   334 simplification;
   335 
   336 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   337 to the simplifier and classical reasoner simultaneously;
   338 
   339 
   340 *** General ***
   341 
   342 * Provers: blast_tac now handles actual object-logic rules as
   343 assumptions; note that auto_tac uses blast_tac internally as well;
   344 
   345 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   346 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   347 
   348 * Provers: delrules now handles destruct rules as well (no longer need
   349 explicit make_elim);
   350 
   351 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   352   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   353 use instead the strong form,
   354   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   355 in HOL, FOL and ZF the function cla_make_elim will create such rules
   356 from destruct-rules;
   357 
   358 * Provers: Simplifier.easy_setup provides a fast path to basic
   359 Simplifier setup for new object-logics;
   360 
   361 * Pure: AST translation rules no longer require constant head on LHS;
   362 
   363 * Pure: improved name spaces: ambiguous output is qualified; support
   364 for hiding of names;
   365 
   366 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   367 XSYMBOL_HOME; no longer need to do manual configuration in most
   368 situations;
   369 
   370 * system: compression of ML heaps images may now be controlled via -c
   371 option of isabelle and isatool usedir (currently only observed by
   372 Poly/ML);
   373 
   374 * system: isatool installfonts may handle X-Symbol fonts as well (very
   375 useful for remote X11);
   376 
   377 * system: provide TAGS file for Isabelle sources;
   378 
   379 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   380 order;
   381 
   382 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   383 timing flag supersedes proof_timing and Toplevel.trace;
   384 
   385 * ML: new combinators |>> and |>>> for incremental transformations
   386 with secondary results (e.g. certain theory extensions):
   387 
   388 * ML: PureThy.add_defs gets additional argument to indicate potential
   389 overloading (usually false);
   390 
   391 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   392 results;
   393 
   394 
   395 
   396 New in Isabelle99 (October 1999)
   397 --------------------------------
   398 
   399 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   400 
   401 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   402 are no longer simplified.  (This allows the simplifier to unfold recursive
   403 functional programs.)  To restore the old behaviour, declare
   404 
   405     Delcongs [if_weak_cong];
   406 
   407 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   408 complement;
   409 
   410 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   411 
   412 * HOL/datatype: mutual_induct_tac no longer exists --
   413   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   414 
   415 * HOL/typedef: fixed type inference for representing set; type
   416 arguments now have to occur explicitly on the rhs as type constraints;
   417 
   418 * ZF: The con_defs part of an inductive definition may no longer refer
   419 to constants declared in the same theory;
   420 
   421 * HOL, ZF: the function mk_cases, generated by the inductive
   422 definition package, has lost an argument.  To simplify its result, it
   423 uses the default simpset instead of a supplied list of theorems.
   424 
   425 * HOL/List: the constructors of type list are now Nil and Cons;
   426 
   427 * Simplifier: the type of the infix ML functions
   428         setSSolver addSSolver setSolver addSolver
   429 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   430 for packaging solvers. A solver is created via
   431         mk_solver: string -> (thm list -> int -> tactic) -> solver
   432 where the string argument is only a comment.
   433 
   434 
   435 *** Proof tools ***
   436 
   437 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   438 decision procedure for linear arithmetic. Currently it is used for
   439 types `nat', `int', and `real' in HOL (see below); it can, should and
   440 will be instantiated for other types and logics as well.
   441 
   442 * The simplifier now accepts rewrite rules with flexible heads, eg
   443      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   444   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   445   matching.
   446 
   447 
   448 *** General ***
   449 
   450 * New Isabelle/Isar subsystem provides an alternative to traditional
   451 tactical theorem proving; together with the ProofGeneral/isar user
   452 interface it offers an interactive environment for developing human
   453 readable proof documents (Isar == Intelligible semi-automated
   454 reasoning); for further information see isatool doc isar-ref,
   455 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   456 
   457 * improved and simplified presentation of theories: better HTML markup
   458 (including colors), graph views in several sizes; isatool usedir now
   459 provides a proper interface for user theories (via -P option); actual
   460 document preparation based on (PDF)LaTeX is available as well (for
   461 new-style theories only); see isatool doc system for more information;
   462 
   463 * native support for Proof General, both for classic Isabelle and
   464 Isabelle/Isar;
   465 
   466 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   467 using the graph browser tool;
   468 
   469 * Isabelle manuals now also available as PDF;
   470 
   471 * theory loader rewritten from scratch (may not be fully
   472 bug-compatible); old loadpath variable has been replaced by show_path,
   473 add_path, del_path, reset_path functions; new operations such as
   474 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   475 isatool doc ref);
   476 
   477 * improved isatool install: option -k creates KDE application icon,
   478 option -p DIR installs standalone binaries;
   479 
   480 * added ML_PLATFORM setting (useful for cross-platform installations);
   481 more robust handling of platform specific ML images for SML/NJ;
   482 
   483 * the settings environment is now statically scoped, i.e. it is never
   484 created again in sub-processes invoked from isabelle, isatool, or
   485 Isabelle;
   486 
   487 * path element specification '~~' refers to '$ISABELLE_HOME';
   488 
   489 * in locales, the "assumes" and "defines" parts may be omitted if
   490 empty;
   491 
   492 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   493 long arrows);
   494 
   495 * new print_mode "HTML";
   496 
   497 * new flag show_tags controls display of tags of theorems (which are
   498 basically just comments that may be attached by some tools);
   499 
   500 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   501 mode and goal output format:
   502 
   503 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   504 244c244
   505 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   506 ---
   507 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   508 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   509 181c181
   510 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   511 ---
   512 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   513 
   514 * function bind_thms stores lists of theorems (cf. bind_thm);
   515 
   516 * new shorthand tactics ftac, eatac, datac, fatac;
   517 
   518 * qed (and friends) now accept "" as result name; in that case the
   519 theorem is not stored, but proper checks and presentation of the
   520 result still apply;
   521 
   522 * theorem database now also indexes constants "Trueprop", "all",
   523 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   524 
   525 
   526 *** HOL ***
   527 
   528 ** HOL arithmetic **
   529 
   530 * There are now decision procedures for linear arithmetic over nat and
   531 int:
   532 
   533 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   534 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   535 are treated as atomic; subformulae not involving type `nat' or `int'
   536 are ignored; quantified subformulae are ignored unless they are
   537 positive universal or negative existential. The tactic has to be
   538 invoked by hand and can be a little bit slow. In particular, the
   539 running time is exponential in the number of occurrences of `min' and
   540 `max', and `-' on `nat'.
   541 
   542 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   543 (negated) (in)equalities among the premises and the conclusion into
   544 account (i.e. no compound formulae) and does not know about `min' and
   545 `max', and `-' on `nat'. It is fast and is used automatically by the
   546 simplifier.
   547 
   548 NB: At the moment, these decision procedures do not cope with mixed
   549 nat/int formulae where the two parts interact, such as `m < n ==>
   550 int(m) < int(n)'.
   551 
   552 * HOL/Numeral provides a generic theory of numerals (encoded
   553 efficiently as bit strings); setup for types nat/int/real is in place;
   554 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   555 int, existing theories and proof scripts may require a few additional
   556 type constraints;
   557 
   558 * integer division and remainder can now be performed on constant
   559 arguments;
   560 
   561 * many properties of integer multiplication, division and remainder
   562 are now available;
   563 
   564 * An interface to the Stanford Validity Checker (SVC) is available through the
   565 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   566 are proved automatically.  SVC must be installed separately, and its results
   567 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   568 invocation of the underlying oracle).  For SVC see
   569   http://verify.stanford.edu/SVC
   570 
   571 * IsaMakefile: the HOL-Real target now builds an actual image;
   572 
   573 
   574 ** HOL misc **
   575 
   576 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   577 (in Isabelle/Isar) -- by Gertrud Bauer;
   578 
   579 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   580 analysis for assembly languages with subtypes;
   581 
   582 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   583 -- avoids syntactic ambiguities and treats state, transition, and
   584 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   585 changed syntax and (many) tactics;
   586 
   587 * HOL/inductive: Now also handles more general introduction rules such
   588   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   589   theorems are now maintained within the theory (maintained via the
   590   "mono" attribute);
   591 
   592 * HOL/datatype: Now also handles arbitrarily branching datatypes
   593   (using function types) such as
   594 
   595   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   596 
   597 * HOL/record: record_simproc (part of the default simpset) takes care
   598 of selectors applied to updated records; record_split_tac is no longer
   599 part of the default claset; update_defs may now be removed from the
   600 simpset in many cases; COMPATIBILITY: old behavior achieved by
   601 
   602   claset_ref () := claset() addSWrapper record_split_wrapper;
   603   Delsimprocs [record_simproc]
   604 
   605 * HOL/typedef: fixed type inference for representing set; type
   606 arguments now have to occur explicitly on the rhs as type constraints;
   607 
   608 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   609 names rather than an ML expression;
   610 
   611 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   612 supplied later.  Program schemes can be defined, such as
   613     "While B C s = (if B s then While B C (C s) else s)"
   614 where the well-founded relation can be chosen after B and C have been given.
   615 
   616 * HOL/List: the constructors of type list are now Nil and Cons;
   617 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   618 course, ML tools referring to List.list.op # etc. have to be adapted;
   619 
   620 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   621 disabled by default; run isabelle with option -m HOL to get back to
   622 the original Gordon/HOL-style output;
   623 
   624 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   625 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   626 
   627 * HOL basic syntax simplified (more orthogonal): all variants of
   628 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   629 Eps operator is provided as well: "SOME x. P[x]";
   630 
   631 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   632 
   633 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   634 thus available for user theories;
   635 
   636 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   637 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   638 time;
   639 
   640 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   641 several times and then mp;
   642 
   643 
   644 *** LK ***
   645 
   646 * the notation <<...>> is now available as a notation for sequences of
   647 formulas;
   648 
   649 * the simplifier is now installed
   650 
   651 * the axiom system has been generalized (thanks to Soren Heilmann)
   652 
   653 * the classical reasoner now has a default rule database
   654 
   655 
   656 *** ZF ***
   657 
   658 * new primrec section allows primitive recursive functions to be given
   659 directly (as in HOL) over datatypes and the natural numbers;
   660 
   661 * new tactics induct_tac and exhaust_tac for induction (or case
   662 analysis) over datatypes and the natural numbers;
   663 
   664 * the datatype declaration of type T now defines the recursor T_rec;
   665 
   666 * simplification automatically does freeness reasoning for datatype
   667 constructors;
   668 
   669 * automatic type-inference, with AddTCs command to insert new
   670 type-checking rules;
   671 
   672 * datatype introduction rules are now added as Safe Introduction rules
   673 to the claset;
   674 
   675 * the syntax "if P then x else y" is now available in addition to
   676 if(P,x,y);
   677 
   678 
   679 *** Internal programming interfaces ***
   680 
   681 * tuned simplifier trace output; new flag debug_simp;
   682 
   683 * structures Vartab / Termtab (instances of TableFun) offer efficient
   684 tables indexed by indexname_ord / term_ord (compatible with aconv);
   685 
   686 * AxClass.axclass_tac lost the theory argument;
   687 
   688 * tuned current_goals_markers semantics: begin / end goal avoids
   689 printing empty lines;
   690 
   691 * removed prs and prs_fn hook, which was broken because it did not
   692 include \n in its semantics, forcing writeln to add one
   693 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   694 string -> unit if you really want to output text without newline;
   695 
   696 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   697 plain output, interface builders may have to enable 'isabelle_font'
   698 mode to get Isabelle font glyphs as before;
   699 
   700 * refined token_translation interface; INCOMPATIBILITY: output length
   701 now of type real instead of int;
   702 
   703 * theory loader actions may be traced via new ThyInfo.add_hook
   704 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   705 your own database of information attached to *whole* theories -- as
   706 opposed to intra-theory data slots offered via TheoryDataFun;
   707 
   708 * proper handling of dangling sort hypotheses (at last!);
   709 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   710 extra sort hypotheses that can be witnessed from the type signature;
   711 the force_strip_shyps flag is gone, any remaining shyps are simply
   712 left in the theorem (with a warning issued by strip_shyps_warning);
   713 
   714 
   715 
   716 New in Isabelle98-1 (October 1998)
   717 ----------------------------------
   718 
   719 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   720 
   721 * several changes of automated proof tools;
   722 
   723 * HOL: major changes to the inductive and datatype packages, including
   724 some minor incompatibilities of theory syntax;
   725 
   726 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   727 called `inj_on';
   728 
   729 * HOL: removed duplicate thms in Arith:
   730   less_imp_add_less  should be replaced by  trans_less_add1
   731   le_imp_add_le      should be replaced by  trans_le_add1
   732 
   733 * HOL: unary minus is now overloaded (new type constraints may be
   734 required);
   735 
   736 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   737 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   738 now taken as an integer constant.
   739 
   740 * Pure: ML function 'theory_of' renamed to 'theory';
   741 
   742 
   743 *** Proof tools ***
   744 
   745 * Simplifier:
   746   1. Asm_full_simp_tac is now more aggressive.
   747      1. It will sometimes reorient premises if that increases their power to
   748         simplify.
   749      2. It does no longer proceed strictly from left to right but may also
   750         rotate premises to achieve further simplification.
   751      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   752      old Asm_full_simp_tac in that it does not rotate premises.
   753   2. The simplifier now knows a little bit about nat-arithmetic.
   754 
   755 * Classical reasoner: wrapper mechanism for the classical reasoner now
   756 allows for selected deletion of wrappers, by introduction of names for
   757 wrapper functionals.  This implies that addbefore, addSbefore,
   758 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   759 and that adding two tactics with the same name overwrites the first
   760 one (emitting a warning).
   761   type wrapper = (int -> tactic) -> (int -> tactic)
   762   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   763   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   764   delWrapper, delSWrapper: claset *  string            -> claset
   765   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   766 
   767 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   768 semantics; addbefore now affects only the unsafe part of step_tac
   769 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   770 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   771 by Force_tac;
   772 
   773 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   774 compWrapper; added safe wrapper (and access functions for it);
   775 
   776 * HOL/split_all_tac is now much faster and fails if there is nothing
   777 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   778 and the names of the automatically generated variables have changed.
   779 split_all_tac has moved within claset() from unsafe wrappers to safe
   780 wrappers, which means that !!-bound variables are split much more
   781 aggressively, and safe_tac and clarify_tac now split such variables.
   782 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   783 Note: the same holds for record_split_tac, which does the job of
   784 split_all_tac for record fields.
   785 
   786 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   787 permanently to the default simpset using Addsplits just like
   788 Addsimps. They can be removed via Delsplits just like
   789 Delsimps. Lower-case versions are also available.
   790 
   791 * HOL/Simplifier: The rule split_if is now part of the default
   792 simpset. This means that the simplifier will eliminate all occurrences
   793 of if-then-else in the conclusion of a goal. To prevent this, you can
   794 either remove split_if completely from the default simpset by
   795 `Delsplits [split_if]' or remove it in a specific call of the
   796 simplifier using `... delsplits [split_if]'.  You can also add/delete
   797 other case splitting rules to/from the default simpset: every datatype
   798 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   799 t is the name of the datatype).
   800 
   801 * Classical reasoner / Simplifier combination: new force_tac (and
   802 derivatives Force_tac, force) combines rewriting and classical
   803 reasoning (and whatever other tools) similarly to auto_tac, but is
   804 aimed to solve the given subgoal completely.
   805 
   806 
   807 *** General ***
   808 
   809 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   810 and `goalw': the theory is no longer needed as an explicit argument -
   811 the current theory context is used; assumptions are no longer returned
   812 at the ML-level unless one of them starts with ==> or !!; it is
   813 recommended to convert to these new commands using isatool fixgoal
   814 (backup your sources first!);
   815 
   816 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   817 the current theory context, and 'theory' to lookup stored theories;
   818 
   819 * new theory section 'locale' for declaring constants, assumptions and
   820 definitions that have local scope;
   821 
   822 * new theory section 'nonterminals' for purely syntactic types;
   823 
   824 * new theory section 'setup' for generic ML setup functions
   825 (e.g. package initialization);
   826 
   827 * the distribution now includes Isabelle icons: see
   828 lib/logo/isabelle-{small,tiny}.xpm;
   829 
   830 * isatool install - install binaries with absolute references to
   831 ISABELLE_HOME/bin;
   832 
   833 * isatool logo -- create instances of the Isabelle logo (as EPS);
   834 
   835 * print mode 'emacs' reserved for Isamode;
   836 
   837 * support multiple print (ast) translations per constant name;
   838 
   839 * theorems involving oracles are now printed with a suffixed [!];
   840 
   841 
   842 *** HOL ***
   843 
   844 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   845 
   846 * HOL/inductive package reorganized and improved: now supports mutual
   847 definitions such as
   848 
   849   inductive EVEN ODD
   850     intrs
   851       null "0 : EVEN"
   852       oddI "n : EVEN ==> Suc n : ODD"
   853       evenI "n : ODD ==> Suc n : EVEN"
   854 
   855 new theorem list "elims" contains an elimination rule for each of the
   856 recursive sets; inductive definitions now handle disjunctive premises
   857 correctly (also ZF);
   858 
   859 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   860 "mutual_induct" no longer exists - the induction rule is always
   861 contained in "induct";
   862 
   863 
   864 * HOL/datatype package re-implemented and greatly improved: now
   865 supports mutually recursive datatypes such as
   866 
   867   datatype
   868     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   869             | SUM ('a aexp) ('a aexp)
   870             | DIFF ('a aexp) ('a aexp)
   871             | NUM 'a
   872   and
   873     'a bexp = LESS ('a aexp) ('a aexp)
   874             | AND ('a bexp) ('a bexp)
   875             | OR ('a bexp) ('a bexp)
   876 
   877 as well as indirectly recursive datatypes such as
   878 
   879   datatype
   880     ('a, 'b) term = Var 'a
   881                   | App 'b ((('a, 'b) term) list)
   882 
   883 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   884 induction on mutually / indirectly recursive datatypes.
   885 
   886 Primrec equations are now stored in theory and can be accessed via
   887 <function_name>.simps.
   888 
   889 INCOMPATIBILITIES:
   890 
   891   - Theories using datatypes must now have theory Datatype as an
   892     ancestor.
   893   - The specific <typename>.induct_tac no longer exists - use the
   894     generic induct_tac instead.
   895   - natE has been renamed to nat.exhaust - use exhaust_tac
   896     instead of res_inst_tac ... natE. Note that the variable
   897     names in nat.exhaust differ from the names in natE, this
   898     may cause some "fragile" proofs to fail.
   899   - The theorems split_<typename>_case and split_<typename>_case_asm
   900     have been renamed to <typename>.split and <typename>.split_asm.
   901   - Since default sorts of type variables are now handled correctly,
   902     some datatype definitions may have to be annotated with explicit
   903     sort constraints.
   904   - Primrec definitions no longer require function name and type
   905     of recursive argument.
   906 
   907 Consider using isatool fixdatatype to adapt your theories and proof
   908 scripts to the new package (backup your sources first!).
   909 
   910 
   911 * HOL/record package: considerably improved implementation; now
   912 includes concrete syntax for record types, terms, updates; theorems
   913 for surjective pairing and splitting !!-bound record variables; proof
   914 support is as follows:
   915 
   916   1) standard conversions (selectors or updates applied to record
   917 constructor terms) are part of the standard simpset;
   918 
   919   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   920 made part of standard simpset and claset via addIffs;
   921 
   922   3) a tactic for record field splitting (record_split_tac) is part of
   923 the standard claset (addSWrapper);
   924 
   925 To get a better idea about these rules you may retrieve them via
   926 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   927 the name of your record type.
   928 
   929 The split tactic 3) conceptually simplifies by the following rule:
   930 
   931   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   932 
   933 Thus any record variable that is bound by meta-all will automatically
   934 blow up into some record constructor term, consequently the
   935 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   936 solve record problems automatically.
   937 
   938 
   939 * reorganized the main HOL image: HOL/Integ and String loaded by
   940 default; theory Main includes everything;
   941 
   942 * automatic simplification of integer sums and comparisons, using cancellation;
   943 
   944 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   945 
   946 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   947 
   948 * many new identities for unions, intersections, set difference, etc.;
   949 
   950 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   951 called split_if, split_split, split_sum_case and split_nat_case (to go
   952 with add/delsplits);
   953 
   954 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   955 (?x::unit) = (); this is made part of the default simpset, which COULD
   956 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   957 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   958 unit_abs_eta_conv is added in order to counter the effect of
   959 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   960 %u.f();
   961 
   962 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   963 makes more sense);
   964 
   965 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   966   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   967   disjointness reasoning but breaking a few old proofs.
   968 
   969 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   970 to 'converse' from 'inverse' (for compatibility with ZF and some
   971 literature);
   972 
   973 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   974 the well-founded relation;
   975 
   976 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   977     Compl A.  The "Compl" syntax remains available as input syntax for this
   978     release ONLY.
   979 
   980 * HOL/Update: new theory of function updates:
   981     f(a:=b) == %x. if x=a then b else f x
   982 may also be iterated as in f(a:=b,c:=d,...);
   983 
   984 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   985 
   986 * HOL/List:
   987   - new function list_update written xs[i:=v] that updates the i-th
   988     list position. May also be iterated as in xs[i:=a,j:=b,...].
   989   - new function `upt' written [i..j(] which generates the list
   990     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   991     bound write [i..j], which is a shorthand for [i..j+1(].
   992   - new lexicographic orderings and corresponding wellfoundedness theorems.
   993 
   994 * HOL/Arith:
   995   - removed 'pred' (predecessor) function;
   996   - generalized some theorems about n-1;
   997   - many new laws about "div" and "mod";
   998   - new laws about greatest common divisors (see theory ex/Primes);
   999 
  1000 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1001 instead of "inverse";
  1002 
  1003 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1004   of the multiset ordering;
  1005 
  1006 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1007   (not included by default);
  1008 
  1009 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1010 
  1011 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1012   programs, i.e. different program variables may have different types.
  1013 
  1014 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1015   [previously, this check worked only if the rewrite rule was unconditional]
  1016   Now rew can involve either definitions or equalities (either == or =).
  1017 
  1018 
  1019 *** ZF ***
  1020 
  1021 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1022   only the theorems proved on ZF.ML;
  1023 
  1024 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1025   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1026   disjointness reasoning but breaking a few old proofs.
  1027 
  1028 * ZF/Update: new theory of function updates
  1029     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1030   may also be iterated as in f(a:=b,c:=d,...);
  1031 
  1032 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1033 
  1034 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1035   [previously, this check worked only if the rewrite rule was unconditional]
  1036   Now rew can involve either definitions or equalities (either == or =).
  1037 
  1038 * case_tac provided for compatibility with HOL
  1039     (like the old excluded_middle_tac, but with subgoals swapped)
  1040 
  1041 
  1042 *** Internal programming interfaces ***
  1043 
  1044 * Pure: several new basic modules made available for general use, see
  1045 also src/Pure/README;
  1046 
  1047 * improved the theory data mechanism to support encapsulation (data
  1048 kind name replaced by private Object.kind, acting as authorization
  1049 key); new type-safe user interface via functor TheoryDataFun; generic
  1050 print_data function becomes basically useless;
  1051 
  1052 * removed global_names compatibility flag -- all theory declarations
  1053 are qualified by default;
  1054 
  1055 * module Pure/Syntax now offers quote / antiquote translation
  1056 functions (useful for Hoare logic etc. with implicit dependencies);
  1057 see HOL/ex/Antiquote for an example use;
  1058 
  1059 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1060 cterm -> thm;
  1061 
  1062 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1063 subgoal;
  1064 
  1065 * Display.print_goals function moved to Locale.print_goals;
  1066 
  1067 * standard print function for goals supports current_goals_markers
  1068 variable for marking begin of proof, end of proof, start of goal; the
  1069 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1070 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1071 for example;
  1072 
  1073 
  1074 
  1075 New in Isabelle98 (January 1998)
  1076 --------------------------------
  1077 
  1078 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1079 
  1080 * changed lexical syntax of terms / types: dots made part of long
  1081 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1082 
  1083 * simpset (and claset) reference variable replaced by functions
  1084 simpset / simpset_ref;
  1085 
  1086 * no longer supports theory aliases (via merge) and non-trivial
  1087 implicit merge of thms' signatures;
  1088 
  1089 * most internal names of constants changed due to qualified names;
  1090 
  1091 * changed Pure/Sequence interface (see Pure/seq.ML);
  1092 
  1093 
  1094 *** General Changes ***
  1095 
  1096 * hierachically structured name spaces (for consts, types, axms, thms
  1097 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1098 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1099 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1100 long_names for fully qualified output names; NOTE: ML programs
  1101 (special tactics, packages etc.) referring to internal names may have
  1102 to be adapted to cope with fully qualified names; in case of severe
  1103 backward campatibility problems try setting 'global_names' at compile
  1104 time to have enrything declared within a flat name space; one may also
  1105 fine tune name declarations in theories via the 'global' and 'local'
  1106 section;
  1107 
  1108 * reimplemented the implicit simpset and claset using the new anytype
  1109 data filed in signatures; references simpset:simpset ref etc. are
  1110 replaced by functions simpset:unit->simpset and
  1111 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1112 to patch your ML files accordingly;
  1113 
  1114 * HTML output now includes theory graph data for display with Java
  1115 applet or isatool browser; data generated automatically via isatool
  1116 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1117 
  1118 * defs may now be conditional; improved rewrite_goals_tac to handle
  1119 conditional equations;
  1120 
  1121 * defs now admits additional type arguments, using TYPE('a) syntax;
  1122 
  1123 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1124 creates a new theory node; implicit merge of thms' signatures is
  1125 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1126 transfer:theory->thm->thm in (rare) cases;
  1127 
  1128 * improved handling of draft signatures / theories; draft thms (and
  1129 ctyps, cterms) are automatically promoted to real ones;
  1130 
  1131 * slightly changed interfaces for oracles: admit many per theory, named
  1132 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1133 
  1134 * print_goals: optional output of const types (set show_consts and
  1135 show_types);
  1136 
  1137 * improved output of warnings (###) and errors (***);
  1138 
  1139 * subgoal_tac displays a warning if the new subgoal has type variables;
  1140 
  1141 * removed old README and Makefiles;
  1142 
  1143 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1144 
  1145 * removed obsolete init_pps and init_database;
  1146 
  1147 * deleted the obsolete tactical STATE, which was declared by
  1148     fun STATE tacfun st = tacfun st st;
  1149 
  1150 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1151 (which abbreviates $HOME);
  1152 
  1153 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1154 use isatool fixseq to adapt your ML programs (this works for fully
  1155 qualified references to the Sequence structure only!);
  1156 
  1157 * use_thy no longer requires writable current directory; it always
  1158 reloads .ML *and* .thy file, if either one is out of date;
  1159 
  1160 
  1161 *** Classical Reasoner ***
  1162 
  1163 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1164 tactics that use classical reasoning to simplify a subgoal without
  1165 splitting it into several subgoals;
  1166 
  1167 * Safe_tac: like safe_tac but uses the default claset;
  1168 
  1169 
  1170 *** Simplifier ***
  1171 
  1172 * added simplification meta rules:
  1173     (asm_)(full_)simplify: simpset -> thm -> thm;
  1174 
  1175 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1176 logics (again);
  1177 
  1178 * added prems argument to simplification procedures;
  1179 
  1180 * HOL, FOL, ZF: added infix function `addsplits':
  1181   instead of `<simpset> setloop (split_tac <thms>)'
  1182   you can simply write `<simpset> addsplits <thms>'
  1183 
  1184 
  1185 *** Syntax ***
  1186 
  1187 * TYPE('a) syntax for type reflection terms;
  1188 
  1189 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1190 
  1191 * pretty printer: changed order of mixfix annotation preference (again!);
  1192 
  1193 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1194 
  1195 
  1196 *** HOL ***
  1197 
  1198 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1199   with `addloop' of the simplifier to faciliate case splitting in premises.
  1200 
  1201 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1202 
  1203 * HOL/Auth: new protocol proofs including some for the Internet
  1204   protocol TLS;
  1205 
  1206 * HOL/Map: new theory of `maps' a la VDM;
  1207 
  1208 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1209 cancelling out common nat summands from =, <, <= (in)equalities, or
  1210 differences; simplification procedures nat_cancel_factor for
  1211 cancelling common factor from =, <, <= (in)equalities over natural
  1212 sums; nat_cancel contains both kinds of procedures, it is installed by
  1213 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1214 
  1215 * HOL/simplifier: terms of the form
  1216   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1217   are rewritten to
  1218   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1219   and those of the form
  1220   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1221   are rewritten to
  1222   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1223 
  1224 * HOL/datatype
  1225   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1226 
  1227   P(t_case f1 ... fn x) =
  1228      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1229         ...
  1230        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1231      )
  1232 
  1233   and a theorem `split_t_case_asm' of the form
  1234 
  1235   P(t_case f1 ... fn x) =
  1236     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1237         ...
  1238        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1239      )
  1240   which can be added to a simpset via `addsplits'. The existing theorems
  1241   expand_list_case and expand_option_case have been renamed to
  1242   split_list_case and split_option_case.
  1243 
  1244 * HOL/Arithmetic:
  1245   - `pred n' is automatically converted to `n-1'.
  1246     Users are strongly encouraged not to use `pred' any longer,
  1247     because it will disappear altogether at some point.
  1248   - Users are strongly encouraged to write "0 < n" rather than
  1249     "n ~= 0". Theorems and proof tools have been modified towards this
  1250     `standard'.
  1251 
  1252 * HOL/Lists:
  1253   the function "set_of_list" has been renamed "set" (and its theorems too);
  1254   the function "nth" now takes its arguments in the reverse order and
  1255   has acquired the infix notation "!" as in "xs!n".
  1256 
  1257 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1258 
  1259 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1260   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1261 
  1262 * HOL/record: extensible records with schematic structural subtyping
  1263 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1264 still lacks various theorems and concrete record syntax;
  1265 
  1266 
  1267 *** HOLCF ***
  1268 
  1269 * removed "axioms" and "generated by" sections;
  1270 
  1271 * replaced "ops" section by extended "consts" section, which is capable of
  1272   handling the continuous function space "->" directly;
  1273 
  1274 * domain package:
  1275   . proves theorems immediately and stores them in the theory,
  1276   . creates hierachical name space,
  1277   . now uses normal mixfix annotations (instead of cinfix...),
  1278   . minor changes to some names and values (for consistency),
  1279   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1280   . separator between mutual domain defs: changed "," to "and",
  1281   . improved handling of sort constraints;  now they have to
  1282     appear on the left-hand side of the equations only;
  1283 
  1284 * fixed LAM <x,y,zs>.b syntax;
  1285 
  1286 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1287 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1288 
  1289 
  1290 *** FOL and ZF ***
  1291 
  1292 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1293   with `addloop' of the simplifier to faciliate case splitting in premises.
  1294 
  1295 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1296 in HOL, they strip ALL and --> from proved theorems;
  1297 
  1298 
  1299 
  1300 New in Isabelle94-8 (May 1997)
  1301 ------------------------------
  1302 
  1303 *** General Changes ***
  1304 
  1305 * new utilities to build / run / maintain Isabelle etc. (in parts
  1306 still somewhat experimental); old Makefiles etc. still functional;
  1307 
  1308 * new 'Isabelle System Manual';
  1309 
  1310 * INSTALL text, together with ./configure and ./build scripts;
  1311 
  1312 * reimplemented type inference for greater efficiency, better error
  1313 messages and clean internal interface;
  1314 
  1315 * prlim command for dealing with lots of subgoals (an easier way of
  1316 setting goals_limit);
  1317 
  1318 
  1319 *** Syntax ***
  1320 
  1321 * supports alternative (named) syntax tables (parser and pretty
  1322 printer); internal interface is provided by add_modesyntax(_i);
  1323 
  1324 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1325 be used in conjunction with the Isabelle symbol font; uses the
  1326 "symbols" syntax table;
  1327 
  1328 * added token_translation interface (may translate name tokens in
  1329 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1330 the current print_mode); IMPORTANT: user print translation functions
  1331 are responsible for marking newly introduced bounds
  1332 (Syntax.mark_boundT);
  1333 
  1334 * token translations for modes "xterm" and "xterm_color" that display
  1335 names in bold, underline etc. or colors (which requires a color
  1336 version of xterm);
  1337 
  1338 * infixes may now be declared with names independent of their syntax;
  1339 
  1340 * added typed_print_translation (like print_translation, but may
  1341 access type of constant);
  1342 
  1343 
  1344 *** Classical Reasoner ***
  1345 
  1346 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1347 some limitations.  Blast_tac...
  1348   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1349   + ignores elimination rules that don't have the correct format
  1350         (the conclusion MUST be a formula variable)
  1351   + ignores types, which can make HOL proofs fail
  1352   + rules must not require higher-order unification, e.g. apply_type in ZF
  1353     [message "Function Var's argument not a bound variable" relates to this]
  1354   + its proof strategy is more general but can actually be slower
  1355 
  1356 * substitution with equality assumptions no longer permutes other
  1357 assumptions;
  1358 
  1359 * minor changes in semantics of addafter (now called addaltern); renamed
  1360 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1361 (and access functions for it);
  1362 
  1363 * improved combination of classical reasoner and simplifier:
  1364   + functions for handling clasimpsets
  1365   + improvement of addss: now the simplifier is called _after_ the
  1366     safe steps.
  1367   + safe variant of addss called addSss: uses safe simplifications
  1368     _during_ the safe steps. It is more complete as it allows multiple
  1369     instantiations of unknowns (e.g. with slow_tac).
  1370 
  1371 *** Simplifier ***
  1372 
  1373 * added interface for simplification procedures (functions that
  1374 produce *proven* rewrite rules on the fly, depending on current
  1375 redex);
  1376 
  1377 * ordering on terms as parameter (used for ordered rewriting);
  1378 
  1379 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1380 
  1381 * the solver is now split into a safe and an unsafe part.
  1382 This should be invisible for the normal user, except that the
  1383 functions setsolver and addsolver have been renamed to setSolver and
  1384 addSolver; added safe_asm_full_simp_tac;
  1385 
  1386 
  1387 *** HOL ***
  1388 
  1389 * a generic induction tactic `induct_tac' which works for all datatypes and
  1390 also for type `nat';
  1391 
  1392 * a generic case distinction tactic `exhaust_tac' which works for all
  1393 datatypes and also for type `nat';
  1394 
  1395 * each datatype comes with a function `size';
  1396 
  1397 * patterns in case expressions allow tuple patterns as arguments to
  1398 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1399 
  1400 * primrec now also works with type nat;
  1401 
  1402 * recdef: a new declaration form, allows general recursive functions to be
  1403 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1404 
  1405 * the constant for negation has been renamed from "not" to "Not" to
  1406 harmonize with FOL, ZF, LK, etc.;
  1407 
  1408 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1409 infinite lists;
  1410 
  1411 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1412 
  1413 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1414 problems in commutative rings, using axiomatic type classes for + and *;
  1415 
  1416 * more examples in HOL/MiniML and HOL/Auth;
  1417 
  1418 * more default rewrite rules for quantifiers, union/intersection;
  1419 
  1420 * a new constant `arbitrary == @x.False';
  1421 
  1422 * HOLCF/IOA replaces old HOL/IOA;
  1423 
  1424 * HOLCF changes: derived all rules and arities
  1425   + axiomatic type classes instead of classes
  1426   + typedef instead of faking type definitions
  1427   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1428   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1429   + eliminated the types void, one, tr
  1430   + use unit lift and bool lift (with translations) instead of one and tr
  1431   + eliminated blift from Lift3.thy (use Def instead of blift)
  1432   all eliminated rules are derived as theorems --> no visible changes ;
  1433 
  1434 
  1435 *** ZF ***
  1436 
  1437 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1438 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1439 as ZF_cs addSIs [equalityI];
  1440 
  1441 
  1442 
  1443 New in Isabelle94-7 (November 96)
  1444 ---------------------------------
  1445 
  1446 * allowing negative levels (as offsets) in prlev and choplev;
  1447 
  1448 * super-linear speedup for large simplifications;
  1449 
  1450 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1451 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1452 FAIL); can suppress it using the command Delsimps (ex_simps @
  1453 all_simps); De Morgan laws are also now included, by default;
  1454 
  1455 * improved printing of ==>  :  ~:
  1456 
  1457 * new object-logic "Sequents" adds linear logic, while replacing LK
  1458 and Modal (thanks to Sara Kalvala);
  1459 
  1460 * HOL/Auth: correctness proofs for authentication protocols;
  1461 
  1462 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1463 examples on HOL/Auth);
  1464 
  1465 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1466 the rewriter and classical reasoner simultaneously;
  1467 
  1468 * function uresult no longer returns theorems in "standard" format;
  1469 regain previous version by: val uresult = standard o uresult;
  1470 
  1471 
  1472 
  1473 New in Isabelle94-6
  1474 -------------------
  1475 
  1476 * oracles -- these establish an interface between Isabelle and trusted
  1477 external reasoners, which may deliver results as theorems;
  1478 
  1479 * proof objects (in particular record all uses of oracles);
  1480 
  1481 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1482 
  1483 * "constdefs" section in theory files;
  1484 
  1485 * "primrec" section (HOL) no longer requires names;
  1486 
  1487 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1488 
  1489 
  1490 
  1491 New in Isabelle94-5
  1492 -------------------
  1493 
  1494 * reduced space requirements;
  1495 
  1496 * automatic HTML generation from theories;
  1497 
  1498 * theory files no longer require "..." (quotes) around most types;
  1499 
  1500 * new examples, including two proofs of the Church-Rosser theorem;
  1501 
  1502 * non-curried (1994) version of HOL is no longer distributed;
  1503 
  1504 
  1505 
  1506 New in Isabelle94-4
  1507 -------------------
  1508 
  1509 * greatly reduced space requirements;
  1510 
  1511 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1512 
  1513 * searchable theorem database (see the section "Retrieving theorems" on
  1514 page 8 of the Reference Manual);
  1515 
  1516 * new examples, including Grabczewski's monumental case study of the
  1517 Axiom of Choice;
  1518 
  1519 * The previous version of HOL renamed to Old_HOL;
  1520 
  1521 * The new version of HOL (previously called CHOL) uses a curried syntax
  1522 for functions.  Application looks like f a b instead of f(a,b);
  1523 
  1524 * Mutually recursive inductive definitions finally work in HOL;
  1525 
  1526 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1527 translates to the operator "split";
  1528 
  1529 
  1530 
  1531 New in Isabelle94-3
  1532 -------------------
  1533 
  1534 * new infix operator, addss, allowing the classical reasoner to
  1535 perform simplification at each step of its search.  Example:
  1536         fast_tac (cs addss ss)
  1537 
  1538 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1539 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1540 look like (a,b) instead of <a,b>;
  1541 
  1542 * PLEASE NOTE: CHOL will eventually replace HOL!
  1543 
  1544 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1545 It translates to the operator "split".  A new theory of integers is available;
  1546 
  1547 * In ZF, integer numerals now denote two's-complement binary integers.
  1548 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1549 
  1550 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1551 of the Axiom of Choice;
  1552 
  1553 
  1554 
  1555 New in Isabelle94-2
  1556 -------------------
  1557 
  1558 * Significantly faster resolution;
  1559 
  1560 * the different sections in a .thy file can now be mixed and repeated
  1561 freely;
  1562 
  1563 * Database of theorems for FOL, HOL and ZF.  New
  1564 commands including qed, qed_goal and bind_thm store theorems in the database.
  1565 
  1566 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1567 a given theory (thms_of), or find out what theory a theorem was proved in
  1568 (theory_of_thm);
  1569 
  1570 * Bugs fixed in the inductive definition and datatype packages;
  1571 
  1572 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1573 and HOL_dup_cs obsolete;
  1574 
  1575 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1576 have been removed;
  1577 
  1578 * Simpler definition of function space in ZF;
  1579 
  1580 * new results about cardinal and ordinal arithmetic in ZF;
  1581 
  1582 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1583 types;
  1584 
  1585 
  1586 $Id$