NEWS
author nipkow
Mon Oct 16 10:59:35 2000 +0200 (2000-10-16)
changeset 10224 7263c856787e
parent 10164 c240747082aa
child 10245 87771e2f49fe
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 *** Overview of INCOMPATIBILITIES ***
     5 
     6 * HOL: induct renamed to lfp_induct;
     7 
     8 
     9 New in Isabelle99-1 (October 2000)
    10 ----------------------------------
    11 
    12 *** Overview of INCOMPATIBILITIES ***
    13 
    14 * HOL: simplification of natural numbers is much changed; to partly
    15 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
    16 issue the following ML commands:
    17 
    18   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
    19   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
    20 
    21 * HOL: simplification no longer dives into case-expressions; this is
    22 controlled by "t.weak_case_cong" for each datatype t;
    23 
    24 * HOL: nat_less_induct renamed to less_induct;
    25 
    26 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
    27 fixsome to patch .thy and .ML sources automatically;
    28 
    29   select_equality  -> some_equality
    30   select_eq_Ex     -> some_eq_ex
    31   selectI2EX       -> someI2_ex
    32   selectI2         -> someI2
    33   selectI          -> someI
    34   select1_equality -> some1_equality
    35   Eps_sym_eq       -> some_sym_eq_trivial
    36   Eps_eq           -> some_eq_trivial
    37 
    38 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    39 
    40 * HOL: removed obsolete theorem binding expand_if (refer to split_if
    41 instead);
    42 
    43 * HOL: the recursion equations generated by 'recdef' are now called
    44 f.simps instead of f.rules;
    45 
    46 * HOL: qed_spec_mp now also handles bounded ALL as well;
    47 
    48 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
    49 sometimes be needed;
    50 
    51 * HOL: the constant for "f``x" is now "image" rather than "op ``";
    52 
    53 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
    54 
    55 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
    56 product is now "<*>" instead of "Times"; the lexicographic product is
    57 now "<*lex*>" instead of "**";
    58 
    59 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
    60 of main HOL, but was unused); better use HOL's datatype package;
    61 
    62 * HOL: removed "symbols" syntax for constant "override" of theory Map;
    63 the old syntax may be recovered as follows:
    64 
    65   syntax (symbols)
    66     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
    67       (infixl "\\<oplus>" 100)
    68 
    69 * HOL/Real: "rabs" replaced by overloaded "abs" function;
    70 
    71 * HOL/ML: even fewer consts are declared as global (see theories Ord,
    72 Lfp, Gfp, WF); this only affects ML packages that refer to const names
    73 internally;
    74 
    75 * HOL and ZF: syntax for quotienting wrt an equivalence relation
    76 changed from A/r to A//r;
    77 
    78 * ZF: new treatment of arithmetic (nat & int) may break some old
    79 proofs;
    80 
    81 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
    82 rulify -> rule_format, elimify -> elim_format, ...);
    83 
    84 * Isar/Provers: intro/elim/dest attributes changed; renamed
    85 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
    86 should have to change intro!! to intro? only); replaced "delrule" by
    87 "rule del";
    88 
    89 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
    90 
    91 * Provers: strengthened force_tac by using new first_best_tac;
    92 
    93 * LaTeX document preparation: several changes of isabelle.sty (see
    94 lib/texinputs);
    95 
    96 
    97 *** Document preparation ***
    98 
    99 * formal comments (text blocks etc.) in new-style theories may now
   100 contain antiquotations of thm/prop/term/typ/text to be presented
   101 according to latex print mode; concrete syntax is like this:
   102 @{term[show_types] "f(x) = a + x"};
   103 
   104 * isatool mkdir provides easy setup of Isabelle session directories,
   105 including proper document sources;
   106 
   107 * generated LaTeX sources are now deleted after successful run
   108 (isatool document -c); may retain a copy somewhere else via -D option
   109 of isatool usedir;
   110 
   111 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   112 style files, achieving self-contained LaTeX sources and simplifying
   113 LaTeX debugging;
   114 
   115 * old-style theories now produce (crude) LaTeX output as well;
   116 
   117 * browser info session directories are now self-contained (may be put
   118 on WWW server seperately); improved graphs of nested sessions; removed
   119 graph for 'all sessions';
   120 
   121 * several improvements in isabelle style files; \isabellestyle{it}
   122 produces fake math mode output; \isamarkupheader is now \section by
   123 default; see lib/texinputs/isabelle.sty etc.;
   124 
   125 
   126 *** Isar ***
   127 
   128 * Isar/Pure: local results and corresponding term bindings are now
   129 subject to Hindley-Milner polymorphism (similar to ML); this
   130 accommodates incremental type-inference very nicely;
   131 
   132 * Isar/Pure: new derived language element 'obtain' supports
   133 generalized existence reasoning;
   134 
   135 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
   136 support accumulation of results, without applying any rules yet;
   137 useful to collect intermediate results without explicit name
   138 references, and for use with transitivity rules with more than 2
   139 premises;
   140 
   141 * Isar/Pure: scalable support for case-analysis type proofs: new
   142 'case' language element refers to local contexts symbolically, as
   143 produced by certain proof methods; internally, case names are attached
   144 to theorems as "tags";
   145 
   146 * Isar/Pure: theory command 'hide' removes declarations from
   147 class/type/const name spaces;
   148 
   149 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
   150 indicate potential overloading;
   151 
   152 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
   153 
   154 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
   155 "{a,b,c}" instead of {a,b,c};
   156 
   157 * Isar/Pure now provides its own version of intro/elim/dest
   158 attributes; useful for building new logics, but beware of confusion
   159 with the version in Provers/classical;
   160 
   161 * Isar/Pure: the local context of (non-atomic) goals is provided via
   162 case name 'antecedent';
   163 
   164 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
   165 to the current context is now done automatically);
   166 
   167 * Isar/Pure: theory command 'method_setup' provides a simple interface
   168 for definining proof methods in ML;
   169 
   170 * Isar/Provers: intro/elim/dest attributes changed; renamed
   171 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
   172 most cases, one should have to change intro!! to intro? only);
   173 replaced "delrule" by "rule del";
   174 
   175 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
   176 'symmetric' attribute (the latter supercedes [RS sym]);
   177 
   178 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
   179 method modifier); 'simp' method: 'only:' modifier removes loopers as
   180 well (including splits);
   181 
   182 * Isar/Provers: Simplifier and Classical methods now support all kind
   183 of modifiers used in the past, including 'cong', 'iff', etc.
   184 
   185 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
   186 of Simplifier and Classical reasoner);
   187 
   188 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
   189 now support named cases; major packages (inductive, datatype, primrec,
   190 recdef) support case names and properly name parameters;
   191 
   192 * Isar/HOL: new transitivity rules for substitution in inequalities --
   193 monotonicity conditions are extracted to be proven at end of
   194 calculations;
   195 
   196 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
   197 method anyway;
   198 
   199 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
   200 split_if split_if_asm; datatype package provides theorems foo.splits =
   201 foo.split foo.split_asm for each datatype;
   202 
   203 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
   204 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
   205 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
   206 use "(cases (simplified))" method in proper proof texts);
   207 
   208 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
   209 
   210 * Isar: names of theorems etc. may be natural numbers as well;
   211 
   212 * Isar: 'pr' command: optional arguments for goals_limit and
   213 ProofContext.prems_limit; no longer prints theory contexts, but only
   214 proof states;
   215 
   216 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
   217 additional print modes to be specified; e.g. "pr(latex)" will print
   218 proof state according to the Isabelle LaTeX style;
   219 
   220 * Isar: improved support for emulating tactic scripts, including proof
   221 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
   222 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
   223 (for HOL datatypes);
   224 
   225 * Isar: simplified (more robust) goal selection of proof methods: 1st
   226 goal, all goals, or explicit goal specifier (tactic emulation); thus
   227 'proof method scripts' have to be in depth-first order;
   228 
   229 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
   230 
   231 * Isar: removed 'help' command, which hasn't been too helpful anyway;
   232 should instead use individual commands for printing items
   233 (print_commands, print_methods etc.);
   234 
   235 * Isar: added 'nothing' --- the empty list of theorems;
   236 
   237 
   238 *** HOL ***
   239 
   240 * HOL/MicroJava: formalization of a fragment of Java, together with a
   241 corresponding virtual machine and a specification of its bytecode
   242 verifier and a lightweight bytecode verifier, including proofs of
   243 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
   244 Cornelia Pusch (see also the homepage of project Bali at
   245 http://isabelle.in.tum.de/Bali/);
   246 
   247 * HOL/Algebra: new theory of rings and univariate polynomials, by
   248 Clemens Ballarin;
   249 
   250 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
   251 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
   252 Rasmussen;
   253 
   254 * HOL/Lattice: fundamental concepts of lattice theory and order
   255 structures, including duals, properties of bounds versus algebraic
   256 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
   257 Theorem for complete lattices etc.; may also serve as a demonstration
   258 for abstract algebraic reasoning using axiomatic type classes, and
   259 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
   260 
   261 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
   262 von Oheimb;
   263 
   264 * HOL/IMPP: extension of IMP with local variables and mutually
   265 recursive procedures, by David von Oheimb;
   266 
   267 * HOL/Lambda: converted into new-style theory and document;
   268 
   269 * HOL/ex/Multiquote: example of multiple nested quotations and
   270 anti-quotations -- basically a generalized version of de-Bruijn
   271 representation; very useful in avoiding lifting of operations;
   272 
   273 * HOL/record: added general record equality rule to simpset; fixed
   274 select-update simplification procedure to handle extended records as
   275 well; admit "r" as field name;
   276 
   277 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
   278 other numeric types and also as the identity of groups, rings, etc.;
   279 
   280 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
   281 Types nat and int belong to this axclass;
   282 
   283 * HOL: greatly improved simplification involving numerals of type nat, int, real:
   284    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   285    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   286   two terms #m*u and #n*u are replaced by #(m+n)*u
   287     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   288   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   289     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   290 
   291 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
   292 powerful prover for predicate logic but knows nothing of clasets; see
   293 ex/mesontest.ML and ex/mesontest2.ML for example applications;
   294 
   295 * HOL: new version of "case_tac" subsumes both boolean case split and
   296 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   297 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   298 
   299 * HOL: simplification no longer dives into case-expressions: only the
   300 selector expression is simplified, but not the remaining arms; to
   301 enable full simplification of case-expressions for datatype t, you may
   302 remove t.weak_case_cong from the simpset, either globally (Delcongs
   303 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
   304 
   305 * HOL/recdef: the recursion equations generated by 'recdef' for
   306 function 'f' are now called f.simps instead of f.rules; if all
   307 termination conditions are proved automatically, these simplification
   308 rules are added to the simpset, as in primrec; rules may be named
   309 individually as well, resulting in a separate list of theorems for
   310 each equation;
   311 
   312 * HOL/While is a new theory that provides a while-combinator. It
   313 permits the definition of tail-recursive functions without the
   314 provision of a termination measure. The latter is necessary once the
   315 invariant proof rule for while is applied.
   316 
   317 * HOL: new (overloaded) notation for the set of elements below/above
   318 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
   319 
   320 * HOL: theorems impI, allI, ballI bound as "strip";
   321 
   322 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
   323 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
   324 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
   325 
   326 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   327 
   328 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
   329 main HOL, but was unused);
   330 
   331 * HOL: fewer consts declared as global (e.g. have to refer to
   332 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
   333 
   334 * HOL: tuned AST representation of nested pairs, avoiding bogus output
   335 in case of overlap with user translations (e.g. judgements over
   336 tuples); (note that the underlying logical represenation is still
   337 bogus);
   338 
   339 
   340 *** ZF ***
   341 
   342 * ZF: simplification automatically cancels common terms in arithmetic
   343 expressions over nat and int;
   344 
   345 * ZF: new treatment of nat to minimize type-checking: all operators
   346 coerce their operands to a natural number using the function natify,
   347 making the algebraic laws unconditional;
   348 
   349 * ZF: as above, for int: operators coerce their operands to an integer
   350 using the function intify;
   351 
   352 * ZF: the integer library now contains many of the usual laws for the
   353 orderings, including $<=, and monotonicity laws for $+ and $*;
   354 
   355 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
   356 simplification;
   357 
   358 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
   359 to the simplifier and classical reasoner simultaneously;
   360 
   361 
   362 *** General ***
   363 
   364 * Provers: blast_tac now handles actual object-logic rules as
   365 assumptions; note that auto_tac uses blast_tac internally as well;
   366 
   367 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
   368 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
   369 
   370 * Provers: delrules now handles destruct rules as well (no longer need
   371 explicit make_elim);
   372 
   373 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
   374   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   375 use instead the strong form,
   376   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
   377 in HOL, FOL and ZF the function cla_make_elim will create such rules
   378 from destruct-rules;
   379 
   380 * Provers: Simplifier.easy_setup provides a fast path to basic
   381 Simplifier setup for new object-logics;
   382 
   383 * Pure: AST translation rules no longer require constant head on LHS;
   384 
   385 * Pure: improved name spaces: ambiguous output is qualified; support
   386 for hiding of names;
   387 
   388 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
   389 XSYMBOL_HOME; no longer need to do manual configuration in most
   390 situations;
   391 
   392 * system: compression of ML heaps images may now be controlled via -c
   393 option of isabelle and isatool usedir (currently only observed by
   394 Poly/ML);
   395 
   396 * system: isatool installfonts may handle X-Symbol fonts as well (very
   397 useful for remote X11);
   398 
   399 * system: provide TAGS file for Isabelle sources;
   400 
   401 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
   402 order;
   403 
   404 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
   405 timing flag supersedes proof_timing and Toplevel.trace;
   406 
   407 * ML: new combinators |>> and |>>> for incremental transformations
   408 with secondary results (e.g. certain theory extensions):
   409 
   410 * ML: PureThy.add_defs gets additional argument to indicate potential
   411 overloading (usually false);
   412 
   413 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
   414 results;
   415 
   416 
   417 
   418 New in Isabelle99 (October 1999)
   419 --------------------------------
   420 
   421 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   422 
   423 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   424 are no longer simplified.  (This allows the simplifier to unfold recursive
   425 functional programs.)  To restore the old behaviour, declare
   426 
   427     Delcongs [if_weak_cong];
   428 
   429 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   430 complement;
   431 
   432 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   433 
   434 * HOL/datatype: mutual_induct_tac no longer exists --
   435   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   436 
   437 * HOL/typedef: fixed type inference for representing set; type
   438 arguments now have to occur explicitly on the rhs as type constraints;
   439 
   440 * ZF: The con_defs part of an inductive definition may no longer refer
   441 to constants declared in the same theory;
   442 
   443 * HOL, ZF: the function mk_cases, generated by the inductive
   444 definition package, has lost an argument.  To simplify its result, it
   445 uses the default simpset instead of a supplied list of theorems.
   446 
   447 * HOL/List: the constructors of type list are now Nil and Cons;
   448 
   449 * Simplifier: the type of the infix ML functions
   450         setSSolver addSSolver setSolver addSolver
   451 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   452 for packaging solvers. A solver is created via
   453         mk_solver: string -> (thm list -> int -> tactic) -> solver
   454 where the string argument is only a comment.
   455 
   456 
   457 *** Proof tools ***
   458 
   459 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   460 decision procedure for linear arithmetic. Currently it is used for
   461 types `nat', `int', and `real' in HOL (see below); it can, should and
   462 will be instantiated for other types and logics as well.
   463 
   464 * The simplifier now accepts rewrite rules with flexible heads, eg
   465      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   466   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   467   matching.
   468 
   469 
   470 *** General ***
   471 
   472 * New Isabelle/Isar subsystem provides an alternative to traditional
   473 tactical theorem proving; together with the ProofGeneral/isar user
   474 interface it offers an interactive environment for developing human
   475 readable proof documents (Isar == Intelligible semi-automated
   476 reasoning); for further information see isatool doc isar-ref,
   477 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   478 
   479 * improved and simplified presentation of theories: better HTML markup
   480 (including colors), graph views in several sizes; isatool usedir now
   481 provides a proper interface for user theories (via -P option); actual
   482 document preparation based on (PDF)LaTeX is available as well (for
   483 new-style theories only); see isatool doc system for more information;
   484 
   485 * native support for Proof General, both for classic Isabelle and
   486 Isabelle/Isar;
   487 
   488 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   489 using the graph browser tool;
   490 
   491 * Isabelle manuals now also available as PDF;
   492 
   493 * theory loader rewritten from scratch (may not be fully
   494 bug-compatible); old loadpath variable has been replaced by show_path,
   495 add_path, del_path, reset_path functions; new operations such as
   496 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   497 isatool doc ref);
   498 
   499 * improved isatool install: option -k creates KDE application icon,
   500 option -p DIR installs standalone binaries;
   501 
   502 * added ML_PLATFORM setting (useful for cross-platform installations);
   503 more robust handling of platform specific ML images for SML/NJ;
   504 
   505 * the settings environment is now statically scoped, i.e. it is never
   506 created again in sub-processes invoked from isabelle, isatool, or
   507 Isabelle;
   508 
   509 * path element specification '~~' refers to '$ISABELLE_HOME';
   510 
   511 * in locales, the "assumes" and "defines" parts may be omitted if
   512 empty;
   513 
   514 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   515 long arrows);
   516 
   517 * new print_mode "HTML";
   518 
   519 * new flag show_tags controls display of tags of theorems (which are
   520 basically just comments that may be attached by some tools);
   521 
   522 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   523 mode and goal output format:
   524 
   525 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   526 244c244
   527 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   528 ---
   529 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   530 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   531 181c181
   532 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   533 ---
   534 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   535 
   536 * function bind_thms stores lists of theorems (cf. bind_thm);
   537 
   538 * new shorthand tactics ftac, eatac, datac, fatac;
   539 
   540 * qed (and friends) now accept "" as result name; in that case the
   541 theorem is not stored, but proper checks and presentation of the
   542 result still apply;
   543 
   544 * theorem database now also indexes constants "Trueprop", "all",
   545 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   546 
   547 
   548 *** HOL ***
   549 
   550 ** HOL arithmetic **
   551 
   552 * There are now decision procedures for linear arithmetic over nat and
   553 int:
   554 
   555 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   556 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   557 are treated as atomic; subformulae not involving type `nat' or `int'
   558 are ignored; quantified subformulae are ignored unless they are
   559 positive universal or negative existential. The tactic has to be
   560 invoked by hand and can be a little bit slow. In particular, the
   561 running time is exponential in the number of occurrences of `min' and
   562 `max', and `-' on `nat'.
   563 
   564 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   565 (negated) (in)equalities among the premises and the conclusion into
   566 account (i.e. no compound formulae) and does not know about `min' and
   567 `max', and `-' on `nat'. It is fast and is used automatically by the
   568 simplifier.
   569 
   570 NB: At the moment, these decision procedures do not cope with mixed
   571 nat/int formulae where the two parts interact, such as `m < n ==>
   572 int(m) < int(n)'.
   573 
   574 * HOL/Numeral provides a generic theory of numerals (encoded
   575 efficiently as bit strings); setup for types nat/int/real is in place;
   576 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   577 int, existing theories and proof scripts may require a few additional
   578 type constraints;
   579 
   580 * integer division and remainder can now be performed on constant
   581 arguments;
   582 
   583 * many properties of integer multiplication, division and remainder
   584 are now available;
   585 
   586 * An interface to the Stanford Validity Checker (SVC) is available through the
   587 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   588 are proved automatically.  SVC must be installed separately, and its results
   589 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   590 invocation of the underlying oracle).  For SVC see
   591   http://verify.stanford.edu/SVC
   592 
   593 * IsaMakefile: the HOL-Real target now builds an actual image;
   594 
   595 
   596 ** HOL misc **
   597 
   598 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   599 (in Isabelle/Isar) -- by Gertrud Bauer;
   600 
   601 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   602 analysis for assembly languages with subtypes;
   603 
   604 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   605 -- avoids syntactic ambiguities and treats state, transition, and
   606 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   607 changed syntax and (many) tactics;
   608 
   609 * HOL/inductive: Now also handles more general introduction rules such
   610   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   611   theorems are now maintained within the theory (maintained via the
   612   "mono" attribute);
   613 
   614 * HOL/datatype: Now also handles arbitrarily branching datatypes
   615   (using function types) such as
   616 
   617   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   618 
   619 * HOL/record: record_simproc (part of the default simpset) takes care
   620 of selectors applied to updated records; record_split_tac is no longer
   621 part of the default claset; update_defs may now be removed from the
   622 simpset in many cases; COMPATIBILITY: old behavior achieved by
   623 
   624   claset_ref () := claset() addSWrapper record_split_wrapper;
   625   Delsimprocs [record_simproc]
   626 
   627 * HOL/typedef: fixed type inference for representing set; type
   628 arguments now have to occur explicitly on the rhs as type constraints;
   629 
   630 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   631 names rather than an ML expression;
   632 
   633 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   634 supplied later.  Program schemes can be defined, such as
   635     "While B C s = (if B s then While B C (C s) else s)"
   636 where the well-founded relation can be chosen after B and C have been given.
   637 
   638 * HOL/List: the constructors of type list are now Nil and Cons;
   639 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   640 course, ML tools referring to List.list.op # etc. have to be adapted;
   641 
   642 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   643 disabled by default; run isabelle with option -m HOL to get back to
   644 the original Gordon/HOL-style output;
   645 
   646 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   647 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   648 
   649 * HOL basic syntax simplified (more orthogonal): all variants of
   650 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   651 Eps operator is provided as well: "SOME x. P[x]";
   652 
   653 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   654 
   655 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   656 thus available for user theories;
   657 
   658 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   659 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   660 time;
   661 
   662 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   663 several times and then mp;
   664 
   665 
   666 *** LK ***
   667 
   668 * the notation <<...>> is now available as a notation for sequences of
   669 formulas;
   670 
   671 * the simplifier is now installed
   672 
   673 * the axiom system has been generalized (thanks to Soren Heilmann)
   674 
   675 * the classical reasoner now has a default rule database
   676 
   677 
   678 *** ZF ***
   679 
   680 * new primrec section allows primitive recursive functions to be given
   681 directly (as in HOL) over datatypes and the natural numbers;
   682 
   683 * new tactics induct_tac and exhaust_tac for induction (or case
   684 analysis) over datatypes and the natural numbers;
   685 
   686 * the datatype declaration of type T now defines the recursor T_rec;
   687 
   688 * simplification automatically does freeness reasoning for datatype
   689 constructors;
   690 
   691 * automatic type-inference, with AddTCs command to insert new
   692 type-checking rules;
   693 
   694 * datatype introduction rules are now added as Safe Introduction rules
   695 to the claset;
   696 
   697 * the syntax "if P then x else y" is now available in addition to
   698 if(P,x,y);
   699 
   700 
   701 *** Internal programming interfaces ***
   702 
   703 * tuned simplifier trace output; new flag debug_simp;
   704 
   705 * structures Vartab / Termtab (instances of TableFun) offer efficient
   706 tables indexed by indexname_ord / term_ord (compatible with aconv);
   707 
   708 * AxClass.axclass_tac lost the theory argument;
   709 
   710 * tuned current_goals_markers semantics: begin / end goal avoids
   711 printing empty lines;
   712 
   713 * removed prs and prs_fn hook, which was broken because it did not
   714 include \n in its semantics, forcing writeln to add one
   715 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   716 string -> unit if you really want to output text without newline;
   717 
   718 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   719 plain output, interface builders may have to enable 'isabelle_font'
   720 mode to get Isabelle font glyphs as before;
   721 
   722 * refined token_translation interface; INCOMPATIBILITY: output length
   723 now of type real instead of int;
   724 
   725 * theory loader actions may be traced via new ThyInfo.add_hook
   726 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   727 your own database of information attached to *whole* theories -- as
   728 opposed to intra-theory data slots offered via TheoryDataFun;
   729 
   730 * proper handling of dangling sort hypotheses (at last!);
   731 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   732 extra sort hypotheses that can be witnessed from the type signature;
   733 the force_strip_shyps flag is gone, any remaining shyps are simply
   734 left in the theorem (with a warning issued by strip_shyps_warning);
   735 
   736 
   737 
   738 New in Isabelle98-1 (October 1998)
   739 ----------------------------------
   740 
   741 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   742 
   743 * several changes of automated proof tools;
   744 
   745 * HOL: major changes to the inductive and datatype packages, including
   746 some minor incompatibilities of theory syntax;
   747 
   748 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   749 called `inj_on';
   750 
   751 * HOL: removed duplicate thms in Arith:
   752   less_imp_add_less  should be replaced by  trans_less_add1
   753   le_imp_add_le      should be replaced by  trans_le_add1
   754 
   755 * HOL: unary minus is now overloaded (new type constraints may be
   756 required);
   757 
   758 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   759 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   760 now taken as an integer constant.
   761 
   762 * Pure: ML function 'theory_of' renamed to 'theory';
   763 
   764 
   765 *** Proof tools ***
   766 
   767 * Simplifier:
   768   1. Asm_full_simp_tac is now more aggressive.
   769      1. It will sometimes reorient premises if that increases their power to
   770         simplify.
   771      2. It does no longer proceed strictly from left to right but may also
   772         rotate premises to achieve further simplification.
   773      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   774      old Asm_full_simp_tac in that it does not rotate premises.
   775   2. The simplifier now knows a little bit about nat-arithmetic.
   776 
   777 * Classical reasoner: wrapper mechanism for the classical reasoner now
   778 allows for selected deletion of wrappers, by introduction of names for
   779 wrapper functionals.  This implies that addbefore, addSbefore,
   780 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   781 and that adding two tactics with the same name overwrites the first
   782 one (emitting a warning).
   783   type wrapper = (int -> tactic) -> (int -> tactic)
   784   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   785   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   786   delWrapper, delSWrapper: claset *  string            -> claset
   787   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   788 
   789 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   790 semantics; addbefore now affects only the unsafe part of step_tac
   791 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   792 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   793 by Force_tac;
   794 
   795 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   796 compWrapper; added safe wrapper (and access functions for it);
   797 
   798 * HOL/split_all_tac is now much faster and fails if there is nothing
   799 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   800 and the names of the automatically generated variables have changed.
   801 split_all_tac has moved within claset() from unsafe wrappers to safe
   802 wrappers, which means that !!-bound variables are split much more
   803 aggressively, and safe_tac and clarify_tac now split such variables.
   804 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   805 Note: the same holds for record_split_tac, which does the job of
   806 split_all_tac for record fields.
   807 
   808 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   809 permanently to the default simpset using Addsplits just like
   810 Addsimps. They can be removed via Delsplits just like
   811 Delsimps. Lower-case versions are also available.
   812 
   813 * HOL/Simplifier: The rule split_if is now part of the default
   814 simpset. This means that the simplifier will eliminate all occurrences
   815 of if-then-else in the conclusion of a goal. To prevent this, you can
   816 either remove split_if completely from the default simpset by
   817 `Delsplits [split_if]' or remove it in a specific call of the
   818 simplifier using `... delsplits [split_if]'.  You can also add/delete
   819 other case splitting rules to/from the default simpset: every datatype
   820 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   821 t is the name of the datatype).
   822 
   823 * Classical reasoner / Simplifier combination: new force_tac (and
   824 derivatives Force_tac, force) combines rewriting and classical
   825 reasoning (and whatever other tools) similarly to auto_tac, but is
   826 aimed to solve the given subgoal completely.
   827 
   828 
   829 *** General ***
   830 
   831 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   832 and `goalw': the theory is no longer needed as an explicit argument -
   833 the current theory context is used; assumptions are no longer returned
   834 at the ML-level unless one of them starts with ==> or !!; it is
   835 recommended to convert to these new commands using isatool fixgoal
   836 (backup your sources first!);
   837 
   838 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   839 the current theory context, and 'theory' to lookup stored theories;
   840 
   841 * new theory section 'locale' for declaring constants, assumptions and
   842 definitions that have local scope;
   843 
   844 * new theory section 'nonterminals' for purely syntactic types;
   845 
   846 * new theory section 'setup' for generic ML setup functions
   847 (e.g. package initialization);
   848 
   849 * the distribution now includes Isabelle icons: see
   850 lib/logo/isabelle-{small,tiny}.xpm;
   851 
   852 * isatool install - install binaries with absolute references to
   853 ISABELLE_HOME/bin;
   854 
   855 * isatool logo -- create instances of the Isabelle logo (as EPS);
   856 
   857 * print mode 'emacs' reserved for Isamode;
   858 
   859 * support multiple print (ast) translations per constant name;
   860 
   861 * theorems involving oracles are now printed with a suffixed [!];
   862 
   863 
   864 *** HOL ***
   865 
   866 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   867 
   868 * HOL/inductive package reorganized and improved: now supports mutual
   869 definitions such as
   870 
   871   inductive EVEN ODD
   872     intrs
   873       null "0 : EVEN"
   874       oddI "n : EVEN ==> Suc n : ODD"
   875       evenI "n : ODD ==> Suc n : EVEN"
   876 
   877 new theorem list "elims" contains an elimination rule for each of the
   878 recursive sets; inductive definitions now handle disjunctive premises
   879 correctly (also ZF);
   880 
   881 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   882 "mutual_induct" no longer exists - the induction rule is always
   883 contained in "induct";
   884 
   885 
   886 * HOL/datatype package re-implemented and greatly improved: now
   887 supports mutually recursive datatypes such as
   888 
   889   datatype
   890     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   891             | SUM ('a aexp) ('a aexp)
   892             | DIFF ('a aexp) ('a aexp)
   893             | NUM 'a
   894   and
   895     'a bexp = LESS ('a aexp) ('a aexp)
   896             | AND ('a bexp) ('a bexp)
   897             | OR ('a bexp) ('a bexp)
   898 
   899 as well as indirectly recursive datatypes such as
   900 
   901   datatype
   902     ('a, 'b) term = Var 'a
   903                   | App 'b ((('a, 'b) term) list)
   904 
   905 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   906 induction on mutually / indirectly recursive datatypes.
   907 
   908 Primrec equations are now stored in theory and can be accessed via
   909 <function_name>.simps.
   910 
   911 INCOMPATIBILITIES:
   912 
   913   - Theories using datatypes must now have theory Datatype as an
   914     ancestor.
   915   - The specific <typename>.induct_tac no longer exists - use the
   916     generic induct_tac instead.
   917   - natE has been renamed to nat.exhaust - use exhaust_tac
   918     instead of res_inst_tac ... natE. Note that the variable
   919     names in nat.exhaust differ from the names in natE, this
   920     may cause some "fragile" proofs to fail.
   921   - The theorems split_<typename>_case and split_<typename>_case_asm
   922     have been renamed to <typename>.split and <typename>.split_asm.
   923   - Since default sorts of type variables are now handled correctly,
   924     some datatype definitions may have to be annotated with explicit
   925     sort constraints.
   926   - Primrec definitions no longer require function name and type
   927     of recursive argument.
   928 
   929 Consider using isatool fixdatatype to adapt your theories and proof
   930 scripts to the new package (backup your sources first!).
   931 
   932 
   933 * HOL/record package: considerably improved implementation; now
   934 includes concrete syntax for record types, terms, updates; theorems
   935 for surjective pairing and splitting !!-bound record variables; proof
   936 support is as follows:
   937 
   938   1) standard conversions (selectors or updates applied to record
   939 constructor terms) are part of the standard simpset;
   940 
   941   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   942 made part of standard simpset and claset via addIffs;
   943 
   944   3) a tactic for record field splitting (record_split_tac) is part of
   945 the standard claset (addSWrapper);
   946 
   947 To get a better idea about these rules you may retrieve them via
   948 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   949 the name of your record type.
   950 
   951 The split tactic 3) conceptually simplifies by the following rule:
   952 
   953   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   954 
   955 Thus any record variable that is bound by meta-all will automatically
   956 blow up into some record constructor term, consequently the
   957 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   958 solve record problems automatically.
   959 
   960 
   961 * reorganized the main HOL image: HOL/Integ and String loaded by
   962 default; theory Main includes everything;
   963 
   964 * automatic simplification of integer sums and comparisons, using cancellation;
   965 
   966 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   967 
   968 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   969 
   970 * many new identities for unions, intersections, set difference, etc.;
   971 
   972 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   973 called split_if, split_split, split_sum_case and split_nat_case (to go
   974 with add/delsplits);
   975 
   976 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   977 (?x::unit) = (); this is made part of the default simpset, which COULD
   978 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   979 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   980 unit_abs_eta_conv is added in order to counter the effect of
   981 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   982 %u.f();
   983 
   984 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   985 makes more sense);
   986 
   987 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   988   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   989   disjointness reasoning but breaking a few old proofs.
   990 
   991 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   992 to 'converse' from 'inverse' (for compatibility with ZF and some
   993 literature);
   994 
   995 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   996 the well-founded relation;
   997 
   998 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   999     Compl A.  The "Compl" syntax remains available as input syntax for this
  1000     release ONLY.
  1001 
  1002 * HOL/Update: new theory of function updates:
  1003     f(a:=b) == %x. if x=a then b else f x
  1004 may also be iterated as in f(a:=b,c:=d,...);
  1005 
  1006 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1007 
  1008 * HOL/List:
  1009   - new function list_update written xs[i:=v] that updates the i-th
  1010     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1011   - new function `upt' written [i..j(] which generates the list
  1012     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1013     bound write [i..j], which is a shorthand for [i..j+1(].
  1014   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1015 
  1016 * HOL/Arith:
  1017   - removed 'pred' (predecessor) function;
  1018   - generalized some theorems about n-1;
  1019   - many new laws about "div" and "mod";
  1020   - new laws about greatest common divisors (see theory ex/Primes);
  1021 
  1022 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1023 instead of "inverse";
  1024 
  1025 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1026   of the multiset ordering;
  1027 
  1028 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1029   (not included by default);
  1030 
  1031 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1032 
  1033 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1034   programs, i.e. different program variables may have different types.
  1035 
  1036 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1037   [previously, this check worked only if the rewrite rule was unconditional]
  1038   Now rew can involve either definitions or equalities (either == or =).
  1039 
  1040 
  1041 *** ZF ***
  1042 
  1043 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1044   only the theorems proved on ZF.ML;
  1045 
  1046 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1047   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1048   disjointness reasoning but breaking a few old proofs.
  1049 
  1050 * ZF/Update: new theory of function updates
  1051     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1052   may also be iterated as in f(a:=b,c:=d,...);
  1053 
  1054 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1055 
  1056 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1057   [previously, this check worked only if the rewrite rule was unconditional]
  1058   Now rew can involve either definitions or equalities (either == or =).
  1059 
  1060 * case_tac provided for compatibility with HOL
  1061     (like the old excluded_middle_tac, but with subgoals swapped)
  1062 
  1063 
  1064 *** Internal programming interfaces ***
  1065 
  1066 * Pure: several new basic modules made available for general use, see
  1067 also src/Pure/README;
  1068 
  1069 * improved the theory data mechanism to support encapsulation (data
  1070 kind name replaced by private Object.kind, acting as authorization
  1071 key); new type-safe user interface via functor TheoryDataFun; generic
  1072 print_data function becomes basically useless;
  1073 
  1074 * removed global_names compatibility flag -- all theory declarations
  1075 are qualified by default;
  1076 
  1077 * module Pure/Syntax now offers quote / antiquote translation
  1078 functions (useful for Hoare logic etc. with implicit dependencies);
  1079 see HOL/ex/Antiquote for an example use;
  1080 
  1081 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1082 cterm -> thm;
  1083 
  1084 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1085 subgoal;
  1086 
  1087 * Display.print_goals function moved to Locale.print_goals;
  1088 
  1089 * standard print function for goals supports current_goals_markers
  1090 variable for marking begin of proof, end of proof, start of goal; the
  1091 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1092 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1093 for example;
  1094 
  1095 
  1096 
  1097 New in Isabelle98 (January 1998)
  1098 --------------------------------
  1099 
  1100 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1101 
  1102 * changed lexical syntax of terms / types: dots made part of long
  1103 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1104 
  1105 * simpset (and claset) reference variable replaced by functions
  1106 simpset / simpset_ref;
  1107 
  1108 * no longer supports theory aliases (via merge) and non-trivial
  1109 implicit merge of thms' signatures;
  1110 
  1111 * most internal names of constants changed due to qualified names;
  1112 
  1113 * changed Pure/Sequence interface (see Pure/seq.ML);
  1114 
  1115 
  1116 *** General Changes ***
  1117 
  1118 * hierachically structured name spaces (for consts, types, axms, thms
  1119 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  1120 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  1121 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  1122 long_names for fully qualified output names; NOTE: ML programs
  1123 (special tactics, packages etc.) referring to internal names may have
  1124 to be adapted to cope with fully qualified names; in case of severe
  1125 backward campatibility problems try setting 'global_names' at compile
  1126 time to have enrything declared within a flat name space; one may also
  1127 fine tune name declarations in theories via the 'global' and 'local'
  1128 section;
  1129 
  1130 * reimplemented the implicit simpset and claset using the new anytype
  1131 data filed in signatures; references simpset:simpset ref etc. are
  1132 replaced by functions simpset:unit->simpset and
  1133 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  1134 to patch your ML files accordingly;
  1135 
  1136 * HTML output now includes theory graph data for display with Java
  1137 applet or isatool browser; data generated automatically via isatool
  1138 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  1139 
  1140 * defs may now be conditional; improved rewrite_goals_tac to handle
  1141 conditional equations;
  1142 
  1143 * defs now admits additional type arguments, using TYPE('a) syntax;
  1144 
  1145 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  1146 creates a new theory node; implicit merge of thms' signatures is
  1147 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  1148 transfer:theory->thm->thm in (rare) cases;
  1149 
  1150 * improved handling of draft signatures / theories; draft thms (and
  1151 ctyps, cterms) are automatically promoted to real ones;
  1152 
  1153 * slightly changed interfaces for oracles: admit many per theory, named
  1154 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  1155 
  1156 * print_goals: optional output of const types (set show_consts and
  1157 show_types);
  1158 
  1159 * improved output of warnings (###) and errors (***);
  1160 
  1161 * subgoal_tac displays a warning if the new subgoal has type variables;
  1162 
  1163 * removed old README and Makefiles;
  1164 
  1165 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  1166 
  1167 * removed obsolete init_pps and init_database;
  1168 
  1169 * deleted the obsolete tactical STATE, which was declared by
  1170     fun STATE tacfun st = tacfun st st;
  1171 
  1172 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  1173 (which abbreviates $HOME);
  1174 
  1175 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  1176 use isatool fixseq to adapt your ML programs (this works for fully
  1177 qualified references to the Sequence structure only!);
  1178 
  1179 * use_thy no longer requires writable current directory; it always
  1180 reloads .ML *and* .thy file, if either one is out of date;
  1181 
  1182 
  1183 *** Classical Reasoner ***
  1184 
  1185 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  1186 tactics that use classical reasoning to simplify a subgoal without
  1187 splitting it into several subgoals;
  1188 
  1189 * Safe_tac: like safe_tac but uses the default claset;
  1190 
  1191 
  1192 *** Simplifier ***
  1193 
  1194 * added simplification meta rules:
  1195     (asm_)(full_)simplify: simpset -> thm -> thm;
  1196 
  1197 * simplifier.ML no longer part of Pure -- has to be loaded by object
  1198 logics (again);
  1199 
  1200 * added prems argument to simplification procedures;
  1201 
  1202 * HOL, FOL, ZF: added infix function `addsplits':
  1203   instead of `<simpset> setloop (split_tac <thms>)'
  1204   you can simply write `<simpset> addsplits <thms>'
  1205 
  1206 
  1207 *** Syntax ***
  1208 
  1209 * TYPE('a) syntax for type reflection terms;
  1210 
  1211 * no longer handles consts with name "" -- declare as 'syntax' instead;
  1212 
  1213 * pretty printer: changed order of mixfix annotation preference (again!);
  1214 
  1215 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  1216 
  1217 
  1218 *** HOL ***
  1219 
  1220 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1221   with `addloop' of the simplifier to faciliate case splitting in premises.
  1222 
  1223 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  1224 
  1225 * HOL/Auth: new protocol proofs including some for the Internet
  1226   protocol TLS;
  1227 
  1228 * HOL/Map: new theory of `maps' a la VDM;
  1229 
  1230 * HOL/simplifier: simplification procedures nat_cancel_sums for
  1231 cancelling out common nat summands from =, <, <= (in)equalities, or
  1232 differences; simplification procedures nat_cancel_factor for
  1233 cancelling common factor from =, <, <= (in)equalities over natural
  1234 sums; nat_cancel contains both kinds of procedures, it is installed by
  1235 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  1236 
  1237 * HOL/simplifier: terms of the form
  1238   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1239   are rewritten to
  1240   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1241   and those of the form
  1242   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1243   are rewritten to
  1244   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1245 
  1246 * HOL/datatype
  1247   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1248 
  1249   P(t_case f1 ... fn x) =
  1250      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1251         ...
  1252        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1253      )
  1254 
  1255   and a theorem `split_t_case_asm' of the form
  1256 
  1257   P(t_case f1 ... fn x) =
  1258     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1259         ...
  1260        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1261      )
  1262   which can be added to a simpset via `addsplits'. The existing theorems
  1263   expand_list_case and expand_option_case have been renamed to
  1264   split_list_case and split_option_case.
  1265 
  1266 * HOL/Arithmetic:
  1267   - `pred n' is automatically converted to `n-1'.
  1268     Users are strongly encouraged not to use `pred' any longer,
  1269     because it will disappear altogether at some point.
  1270   - Users are strongly encouraged to write "0 < n" rather than
  1271     "n ~= 0". Theorems and proof tools have been modified towards this
  1272     `standard'.
  1273 
  1274 * HOL/Lists:
  1275   the function "set_of_list" has been renamed "set" (and its theorems too);
  1276   the function "nth" now takes its arguments in the reverse order and
  1277   has acquired the infix notation "!" as in "xs!n".
  1278 
  1279 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1280 
  1281 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1282   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1283 
  1284 * HOL/record: extensible records with schematic structural subtyping
  1285 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1286 still lacks various theorems and concrete record syntax;
  1287 
  1288 
  1289 *** HOLCF ***
  1290 
  1291 * removed "axioms" and "generated by" sections;
  1292 
  1293 * replaced "ops" section by extended "consts" section, which is capable of
  1294   handling the continuous function space "->" directly;
  1295 
  1296 * domain package:
  1297   . proves theorems immediately and stores them in the theory,
  1298   . creates hierachical name space,
  1299   . now uses normal mixfix annotations (instead of cinfix...),
  1300   . minor changes to some names and values (for consistency),
  1301   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1302   . separator between mutual domain defs: changed "," to "and",
  1303   . improved handling of sort constraints;  now they have to
  1304     appear on the left-hand side of the equations only;
  1305 
  1306 * fixed LAM <x,y,zs>.b syntax;
  1307 
  1308 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1309 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1310 
  1311 
  1312 *** FOL and ZF ***
  1313 
  1314 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1315   with `addloop' of the simplifier to faciliate case splitting in premises.
  1316 
  1317 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1318 in HOL, they strip ALL and --> from proved theorems;
  1319 
  1320 
  1321 
  1322 New in Isabelle94-8 (May 1997)
  1323 ------------------------------
  1324 
  1325 *** General Changes ***
  1326 
  1327 * new utilities to build / run / maintain Isabelle etc. (in parts
  1328 still somewhat experimental); old Makefiles etc. still functional;
  1329 
  1330 * new 'Isabelle System Manual';
  1331 
  1332 * INSTALL text, together with ./configure and ./build scripts;
  1333 
  1334 * reimplemented type inference for greater efficiency, better error
  1335 messages and clean internal interface;
  1336 
  1337 * prlim command for dealing with lots of subgoals (an easier way of
  1338 setting goals_limit);
  1339 
  1340 
  1341 *** Syntax ***
  1342 
  1343 * supports alternative (named) syntax tables (parser and pretty
  1344 printer); internal interface is provided by add_modesyntax(_i);
  1345 
  1346 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1347 be used in conjunction with the Isabelle symbol font; uses the
  1348 "symbols" syntax table;
  1349 
  1350 * added token_translation interface (may translate name tokens in
  1351 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1352 the current print_mode); IMPORTANT: user print translation functions
  1353 are responsible for marking newly introduced bounds
  1354 (Syntax.mark_boundT);
  1355 
  1356 * token translations for modes "xterm" and "xterm_color" that display
  1357 names in bold, underline etc. or colors (which requires a color
  1358 version of xterm);
  1359 
  1360 * infixes may now be declared with names independent of their syntax;
  1361 
  1362 * added typed_print_translation (like print_translation, but may
  1363 access type of constant);
  1364 
  1365 
  1366 *** Classical Reasoner ***
  1367 
  1368 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1369 some limitations.  Blast_tac...
  1370   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1371   + ignores elimination rules that don't have the correct format
  1372         (the conclusion MUST be a formula variable)
  1373   + ignores types, which can make HOL proofs fail
  1374   + rules must not require higher-order unification, e.g. apply_type in ZF
  1375     [message "Function Var's argument not a bound variable" relates to this]
  1376   + its proof strategy is more general but can actually be slower
  1377 
  1378 * substitution with equality assumptions no longer permutes other
  1379 assumptions;
  1380 
  1381 * minor changes in semantics of addafter (now called addaltern); renamed
  1382 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1383 (and access functions for it);
  1384 
  1385 * improved combination of classical reasoner and simplifier:
  1386   + functions for handling clasimpsets
  1387   + improvement of addss: now the simplifier is called _after_ the
  1388     safe steps.
  1389   + safe variant of addss called addSss: uses safe simplifications
  1390     _during_ the safe steps. It is more complete as it allows multiple
  1391     instantiations of unknowns (e.g. with slow_tac).
  1392 
  1393 *** Simplifier ***
  1394 
  1395 * added interface for simplification procedures (functions that
  1396 produce *proven* rewrite rules on the fly, depending on current
  1397 redex);
  1398 
  1399 * ordering on terms as parameter (used for ordered rewriting);
  1400 
  1401 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1402 
  1403 * the solver is now split into a safe and an unsafe part.
  1404 This should be invisible for the normal user, except that the
  1405 functions setsolver and addsolver have been renamed to setSolver and
  1406 addSolver; added safe_asm_full_simp_tac;
  1407 
  1408 
  1409 *** HOL ***
  1410 
  1411 * a generic induction tactic `induct_tac' which works for all datatypes and
  1412 also for type `nat';
  1413 
  1414 * a generic case distinction tactic `exhaust_tac' which works for all
  1415 datatypes and also for type `nat';
  1416 
  1417 * each datatype comes with a function `size';
  1418 
  1419 * patterns in case expressions allow tuple patterns as arguments to
  1420 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1421 
  1422 * primrec now also works with type nat;
  1423 
  1424 * recdef: a new declaration form, allows general recursive functions to be
  1425 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1426 
  1427 * the constant for negation has been renamed from "not" to "Not" to
  1428 harmonize with FOL, ZF, LK, etc.;
  1429 
  1430 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1431 infinite lists;
  1432 
  1433 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1434 
  1435 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1436 problems in commutative rings, using axiomatic type classes for + and *;
  1437 
  1438 * more examples in HOL/MiniML and HOL/Auth;
  1439 
  1440 * more default rewrite rules for quantifiers, union/intersection;
  1441 
  1442 * a new constant `arbitrary == @x.False';
  1443 
  1444 * HOLCF/IOA replaces old HOL/IOA;
  1445 
  1446 * HOLCF changes: derived all rules and arities
  1447   + axiomatic type classes instead of classes
  1448   + typedef instead of faking type definitions
  1449   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1450   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1451   + eliminated the types void, one, tr
  1452   + use unit lift and bool lift (with translations) instead of one and tr
  1453   + eliminated blift from Lift3.thy (use Def instead of blift)
  1454   all eliminated rules are derived as theorems --> no visible changes ;
  1455 
  1456 
  1457 *** ZF ***
  1458 
  1459 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1460 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1461 as ZF_cs addSIs [equalityI];
  1462 
  1463 
  1464 
  1465 New in Isabelle94-7 (November 96)
  1466 ---------------------------------
  1467 
  1468 * allowing negative levels (as offsets) in prlev and choplev;
  1469 
  1470 * super-linear speedup for large simplifications;
  1471 
  1472 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1473 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1474 FAIL); can suppress it using the command Delsimps (ex_simps @
  1475 all_simps); De Morgan laws are also now included, by default;
  1476 
  1477 * improved printing of ==>  :  ~:
  1478 
  1479 * new object-logic "Sequents" adds linear logic, while replacing LK
  1480 and Modal (thanks to Sara Kalvala);
  1481 
  1482 * HOL/Auth: correctness proofs for authentication protocols;
  1483 
  1484 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1485 examples on HOL/Auth);
  1486 
  1487 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1488 the rewriter and classical reasoner simultaneously;
  1489 
  1490 * function uresult no longer returns theorems in "standard" format;
  1491 regain previous version by: val uresult = standard o uresult;
  1492 
  1493 
  1494 
  1495 New in Isabelle94-6
  1496 -------------------
  1497 
  1498 * oracles -- these establish an interface between Isabelle and trusted
  1499 external reasoners, which may deliver results as theorems;
  1500 
  1501 * proof objects (in particular record all uses of oracles);
  1502 
  1503 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1504 
  1505 * "constdefs" section in theory files;
  1506 
  1507 * "primrec" section (HOL) no longer requires names;
  1508 
  1509 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1510 
  1511 
  1512 
  1513 New in Isabelle94-5
  1514 -------------------
  1515 
  1516 * reduced space requirements;
  1517 
  1518 * automatic HTML generation from theories;
  1519 
  1520 * theory files no longer require "..." (quotes) around most types;
  1521 
  1522 * new examples, including two proofs of the Church-Rosser theorem;
  1523 
  1524 * non-curried (1994) version of HOL is no longer distributed;
  1525 
  1526 
  1527 
  1528 New in Isabelle94-4
  1529 -------------------
  1530 
  1531 * greatly reduced space requirements;
  1532 
  1533 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1534 
  1535 * searchable theorem database (see the section "Retrieving theorems" on
  1536 page 8 of the Reference Manual);
  1537 
  1538 * new examples, including Grabczewski's monumental case study of the
  1539 Axiom of Choice;
  1540 
  1541 * The previous version of HOL renamed to Old_HOL;
  1542 
  1543 * The new version of HOL (previously called CHOL) uses a curried syntax
  1544 for functions.  Application looks like f a b instead of f(a,b);
  1545 
  1546 * Mutually recursive inductive definitions finally work in HOL;
  1547 
  1548 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1549 translates to the operator "split";
  1550 
  1551 
  1552 
  1553 New in Isabelle94-3
  1554 -------------------
  1555 
  1556 * new infix operator, addss, allowing the classical reasoner to
  1557 perform simplification at each step of its search.  Example:
  1558         fast_tac (cs addss ss)
  1559 
  1560 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1561 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1562 look like (a,b) instead of <a,b>;
  1563 
  1564 * PLEASE NOTE: CHOL will eventually replace HOL!
  1565 
  1566 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1567 It translates to the operator "split".  A new theory of integers is available;
  1568 
  1569 * In ZF, integer numerals now denote two's-complement binary integers.
  1570 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1571 
  1572 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1573 of the Axiom of Choice;
  1574 
  1575 
  1576 
  1577 New in Isabelle94-2
  1578 -------------------
  1579 
  1580 * Significantly faster resolution;
  1581 
  1582 * the different sections in a .thy file can now be mixed and repeated
  1583 freely;
  1584 
  1585 * Database of theorems for FOL, HOL and ZF.  New
  1586 commands including qed, qed_goal and bind_thm store theorems in the database.
  1587 
  1588 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1589 a given theory (thms_of), or find out what theory a theorem was proved in
  1590 (theory_of_thm);
  1591 
  1592 * Bugs fixed in the inductive definition and datatype packages;
  1593 
  1594 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1595 and HOL_dup_cs obsolete;
  1596 
  1597 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1598 have been removed;
  1599 
  1600 * Simpler definition of function space in ZF;
  1601 
  1602 * new results about cardinal and ordinal arithmetic in ZF;
  1603 
  1604 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1605 types;
  1606 
  1607 
  1608 $Id$