NEWS
author wenzelm
Mon Feb 21 14:09:40 2000 +0100 (2000-02-21)
changeset 8271 7602b57ba028
parent 8203 2fcc6017cb72
child 8283 0a319c5746eb
permissions -rw-r--r--
HOL/record: fixed select-update simplification procedure to handle
extended records as well;
     1 
     2 Isabelle NEWS -- history user-relevant changes
     3 ==============================================
     4 
     5 New in this Isabelle version
     6 ----------------------------
     7 
     8 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     9 
    10 * HOL: the constant for f``x is now "image" rather than "op ``".
    11 
    12 
    13 *** Isar ***
    14 
    15 * names of theorems etc. may be natural numbers as well;
    16 
    17 * intro/elim/dest attributes: changed ! / !! flags to ? / ??;
    18 
    19 * new 'obtain' language element supports generalized existence proofs;
    20 
    21 
    22 *** HOL ***
    23 
    24 * Algebra: new theory of rings and univariate polynomials, by Clemens
    25 Ballarin;
    26 
    27 * HOL/record: fixed select-update simplification procedure to handle
    28 extended records as well;
    29 
    30 
    31 
    32 New in Isabelle99 (October 1999)
    33 --------------------------------
    34 
    35 *** Overview of INCOMPATIBILITIES (see below for more details) ***
    36 
    37 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
    38 are no longer simplified.  (This allows the simplifier to unfold recursive
    39 functional programs.)  To restore the old behaviour, declare
    40 
    41     Delcongs [if_weak_cong];
    42 
    43 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    44 complement;
    45 
    46 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    47 
    48 * HOL/datatype: mutual_induct_tac no longer exists --
    49   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
    50 
    51 * HOL/typedef: fixed type inference for representing set; type
    52 arguments now have to occur explicitly on the rhs as type constraints;
    53 
    54 * ZF: The con_defs part of an inductive definition may no longer refer
    55 to constants declared in the same theory;
    56 
    57 * HOL, ZF: the function mk_cases, generated by the inductive
    58 definition package, has lost an argument.  To simplify its result, it
    59 uses the default simpset instead of a supplied list of theorems.
    60 
    61 * HOL/List: the constructors of type list are now Nil and Cons;
    62 
    63 * Simplifier: the type of the infix ML functions
    64 	setSSolver addSSolver setSolver addSolver
    65 is now  simpset * solver -> simpset  where `solver' is a new abstract type
    66 for packaging solvers. A solver is created via
    67 	mk_solver: string -> (thm list -> int -> tactic) -> solver
    68 where the string argument is only a comment.
    69 
    70 
    71 *** Proof tools ***
    72 
    73 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
    74 decision procedure for linear arithmetic. Currently it is used for
    75 types `nat', `int', and `real' in HOL (see below); it can, should and
    76 will be instantiated for other types and logics as well.
    77 
    78 * The simplifier now accepts rewrite rules with flexible heads, eg
    79      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
    80   They are applied like any rule with a non-pattern lhs, i.e. by first-order
    81   matching.
    82 
    83 
    84 *** General ***
    85 
    86 * New Isabelle/Isar subsystem provides an alternative to traditional
    87 tactical theorem proving; together with the ProofGeneral/isar user
    88 interface it offers an interactive environment for developing human
    89 readable proof documents (Isar == Intelligible semi-automated
    90 reasoning); for further information see isatool doc isar-ref,
    91 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
    92 
    93 * improved presentation of theories: better HTML markup (including
    94 colors), graph views in several sizes; isatool usedir now provides a
    95 proper interface for user theories (via -P option); actual document
    96 preparation based on (PDF)LaTeX is available as well (for new-style
    97 theories only); see isatool doc system for more information;
    98 
    99 * native support for Proof General, both for classic Isabelle and
   100 Isabelle/Isar;
   101 
   102 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   103 using the graph browser tool;
   104 
   105 * Isabelle manuals now also available as PDF;
   106 
   107 * theory loader rewritten from scratch (may not be fully
   108 bug-compatible); old loadpath variable has been replaced by show_path,
   109 add_path, del_path, reset_path functions; new operations such as
   110 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   111 isatool doc ref);
   112 
   113 * improved isatool install: option -k creates KDE application icon,
   114 option -p DIR installs standalone binaries;
   115 
   116 * added ML_PLATFORM setting (useful for cross-platform installations);
   117 more robust handling of platform specific ML images for SML/NJ;
   118 
   119 * the settings environment is now statically scoped, i.e. it is never
   120 created again in sub-processes invoked from isabelle, isatool, or
   121 Isabelle;
   122 
   123 * path element specification '~~' refers to '$ISABELLE_HOME';
   124 
   125 * in locales, the "assumes" and "defines" parts may be omitted if
   126 empty;
   127 
   128 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   129 long arrows);
   130 
   131 * new print_mode "HTML";
   132 
   133 * new flag show_tags controls display of tags of theorems (which are
   134 basically just comments that may be attached by some tools);
   135 
   136 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   137 mode and goal output format:
   138 
   139 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   140 244c244
   141 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   142 ---
   143 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   144 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   145 181c181
   146 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   147 ---
   148 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   149 
   150 * function bind_thms stores lists of theorems (cf. bind_thm);
   151 
   152 * new shorthand tactics ftac, eatac, datac, fatac;
   153 
   154 * qed (and friends) now accept "" as result name; in that case the
   155 theorem is not stored, but proper checks and presentation of the
   156 result still apply;
   157 
   158 * theorem database now also indexes constants "Trueprop", "all",
   159 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   160 
   161 
   162 *** HOL ***
   163 
   164 ** HOL arithmetic **
   165 
   166 * There are now decision procedures for linear arithmetic over nat and
   167 int:
   168 
   169 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   170 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   171 are treated as atomic; subformulae not involving type `nat' or `int'
   172 are ignored; quantified subformulae are ignored unless they are
   173 positive universal or negative existential. The tactic has to be
   174 invoked by hand and can be a little bit slow. In particular, the
   175 running time is exponential in the number of occurrences of `min' and
   176 `max', and `-' on `nat'.
   177 
   178 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   179 (negated) (in)equalities among the premises and the conclusion into
   180 account (i.e. no compound formulae) and does not know about `min' and
   181 `max', and `-' on `nat'. It is fast and is used automatically by the
   182 simplifier.
   183 
   184 NB: At the moment, these decision procedures do not cope with mixed
   185 nat/int formulae where the two parts interact, such as `m < n ==>
   186 int(m) < int(n)'.
   187 
   188 * HOL/Numeral provides a generic theory of numerals (encoded
   189 efficiently as bit strings); setup for types nat/int/real is in place;
   190 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   191 int, existing theories and proof scripts may require a few additional
   192 type constraints;
   193 
   194 * integer division and remainder can now be performed on constant
   195 arguments;
   196 
   197 * many properties of integer multiplication, division and remainder
   198 are now available;
   199 
   200 * An interface to the Stanford Validity Checker (SVC) is available through the
   201 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   202 are proved automatically.  SVC must be installed separately, and its results
   203 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   204 invocation of the underlying oracle).  For SVC see
   205   http://verify.stanford.edu/SVC
   206 
   207 * IsaMakefile: the HOL-Real target now builds an actual image;
   208 
   209 
   210 ** HOL misc **
   211 
   212 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   213 (in Isabelle/Isar) -- by Gertrud Bauer;
   214 
   215 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   216 analysis for assembly languages with subtypes;
   217 
   218 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   219 -- avoids syntactic ambiguities and treats state, transition, and
   220 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   221 changed syntax and (many) tactics;
   222 
   223 * HOL/inductive: Now also handles more general introduction rules such
   224   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   225   theorems are now maintained within the theory (maintained via the
   226   "mono" attribute);
   227 
   228 * HOL/datatype: Now also handles arbitrarily branching datatypes
   229   (using function types) such as
   230 
   231   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   232 
   233 * HOL/record: record_simproc (part of the default simpset) takes care
   234 of selectors applied to updated records; record_split_tac is no longer
   235 part of the default claset; update_defs may now be removed from the
   236 simpset in many cases; COMPATIBILITY: old behavior achieved by
   237 
   238   claset_ref () := claset() addSWrapper record_split_wrapper;
   239   Delsimprocs [record_simproc]
   240 
   241 * HOL/typedef: fixed type inference for representing set; type
   242 arguments now have to occur explicitly on the rhs as type constraints;
   243 
   244 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   245 names rather than an ML expression;
   246 
   247 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   248 supplied later.  Program schemes can be defined, such as
   249     "While B C s = (if B s then While B C (C s) else s)"
   250 where the well-founded relation can be chosen after B and C have been given.
   251 
   252 * HOL/List: the constructors of type list are now Nil and Cons;
   253 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   254 course, ML tools referring to List.list.op # etc. have to be adapted;
   255 
   256 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   257 disabled by default; run isabelle with option -m HOL to get back to
   258 the original Gordon/HOL-style output;
   259 
   260 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   261 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   262 
   263 * HOL basic syntax simplified (more orthogonal): all variants of
   264 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   265 Eps operator is provided as well: "SOME x. P[x]";
   266 
   267 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   268 
   269 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   270 thus available for user theories;
   271 
   272 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   273 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   274 time;
   275 
   276 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   277 several times and then mp;
   278 
   279 
   280 *** LK ***
   281 
   282 * the notation <<...>> is now available as a notation for sequences of
   283 formulas;
   284 
   285 * the simplifier is now installed
   286 
   287 * the axiom system has been generalized (thanks to Soren Heilmann) 
   288 
   289 * the classical reasoner now has a default rule database
   290 
   291 
   292 *** ZF ***
   293 
   294 * new primrec section allows primitive recursive functions to be given
   295 directly (as in HOL) over datatypes and the natural numbers;
   296 
   297 * new tactics induct_tac and exhaust_tac for induction (or case
   298 analysis) over datatypes and the natural numbers;
   299 
   300 * the datatype declaration of type T now defines the recursor T_rec;
   301 
   302 * simplification automatically does freeness reasoning for datatype
   303 constructors;
   304 
   305 * automatic type-inference, with AddTCs command to insert new
   306 type-checking rules;
   307 
   308 * datatype introduction rules are now added as Safe Introduction rules
   309 to the claset;
   310 
   311 * the syntax "if P then x else y" is now available in addition to
   312 if(P,x,y);
   313 
   314 
   315 *** Internal programming interfaces ***
   316 
   317 * tuned simplifier trace output; new flag debug_simp;
   318 
   319 * structures Vartab / Termtab (instances of TableFun) offer efficient
   320 tables indexed by indexname_ord / term_ord (compatible with aconv);
   321 
   322 * AxClass.axclass_tac lost the theory argument;
   323 
   324 * tuned current_goals_markers semantics: begin / end goal avoids
   325 printing empty lines;
   326 
   327 * removed prs and prs_fn hook, which was broken because it did not
   328 include \n in its semantics, forcing writeln to add one
   329 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   330 string -> unit if you really want to output text without newline;
   331 
   332 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   333 plain output, interface builders may have to enable 'isabelle_font'
   334 mode to get Isabelle font glyphs as before;
   335 
   336 * refined token_translation interface; INCOMPATIBILITY: output length
   337 now of type real instead of int;
   338 
   339 * theory loader actions may be traced via new ThyInfo.add_hook
   340 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   341 your own database of information attached to *whole* theories -- as
   342 opposed to intra-theory data slots offered via TheoryDataFun;
   343 
   344 * proper handling of dangling sort hypotheses (at last!);
   345 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   346 extra sort hypotheses that can be witnessed from the type signature;
   347 the force_strip_shyps flag is gone, any remaining shyps are simply
   348 left in the theorem (with a warning issued by strip_shyps_warning);
   349 
   350 
   351 
   352 New in Isabelle98-1 (October 1998)
   353 ----------------------------------
   354 
   355 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   356 
   357 * several changes of automated proof tools;
   358 
   359 * HOL: major changes to the inductive and datatype packages, including
   360 some minor incompatibilities of theory syntax;
   361 
   362 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   363 called `inj_on';
   364 
   365 * HOL: removed duplicate thms in Arith:
   366   less_imp_add_less  should be replaced by  trans_less_add1
   367   le_imp_add_le      should be replaced by  trans_le_add1
   368 
   369 * HOL: unary minus is now overloaded (new type constraints may be
   370 required);
   371 
   372 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   373 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   374 now taken as an integer constant.
   375 
   376 * Pure: ML function 'theory_of' renamed to 'theory';
   377 
   378 
   379 *** Proof tools ***
   380 
   381 * Simplifier:
   382   1. Asm_full_simp_tac is now more aggressive.
   383      1. It will sometimes reorient premises if that increases their power to
   384         simplify.
   385      2. It does no longer proceed strictly from left to right but may also
   386         rotate premises to achieve further simplification.
   387      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   388      old Asm_full_simp_tac in that it does not rotate premises.
   389   2. The simplifier now knows a little bit about nat-arithmetic.
   390 
   391 * Classical reasoner: wrapper mechanism for the classical reasoner now
   392 allows for selected deletion of wrappers, by introduction of names for
   393 wrapper functionals.  This implies that addbefore, addSbefore,
   394 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   395 and that adding two tactics with the same name overwrites the first
   396 one (emitting a warning).
   397   type wrapper = (int -> tactic) -> (int -> tactic)
   398   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   399   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   400   delWrapper, delSWrapper: claset *  string            -> claset
   401   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   402 
   403 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   404 semantics; addbefore now affects only the unsafe part of step_tac
   405 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   406 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   407 by Force_tac;
   408 
   409 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   410 compWrapper; added safe wrapper (and access functions for it);
   411 
   412 * HOL/split_all_tac is now much faster and fails if there is nothing
   413 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   414 and the names of the automatically generated variables have changed.
   415 split_all_tac has moved within claset() from unsafe wrappers to safe
   416 wrappers, which means that !!-bound variables are split much more
   417 aggressively, and safe_tac and clarify_tac now split such variables.
   418 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   419 Note: the same holds for record_split_tac, which does the job of
   420 split_all_tac for record fields.
   421 
   422 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   423 permanently to the default simpset using Addsplits just like
   424 Addsimps. They can be removed via Delsplits just like
   425 Delsimps. Lower-case versions are also available.
   426 
   427 * HOL/Simplifier: The rule split_if is now part of the default
   428 simpset. This means that the simplifier will eliminate all occurrences
   429 of if-then-else in the conclusion of a goal. To prevent this, you can
   430 either remove split_if completely from the default simpset by
   431 `Delsplits [split_if]' or remove it in a specific call of the
   432 simplifier using `... delsplits [split_if]'.  You can also add/delete
   433 other case splitting rules to/from the default simpset: every datatype
   434 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   435 t is the name of the datatype).
   436 
   437 * Classical reasoner / Simplifier combination: new force_tac (and
   438 derivatives Force_tac, force) combines rewriting and classical
   439 reasoning (and whatever other tools) similarly to auto_tac, but is
   440 aimed to solve the given subgoal completely.
   441 
   442 
   443 *** General ***
   444 
   445 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   446 and `goalw': the theory is no longer needed as an explicit argument -
   447 the current theory context is used; assumptions are no longer returned
   448 at the ML-level unless one of them starts with ==> or !!; it is
   449 recommended to convert to these new commands using isatool fixgoal
   450 (backup your sources first!);
   451 
   452 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   453 the current theory context, and 'theory' to lookup stored theories;
   454 
   455 * new theory section 'locale' for declaring constants, assumptions and
   456 definitions that have local scope;
   457 
   458 * new theory section 'nonterminals' for purely syntactic types;
   459 
   460 * new theory section 'setup' for generic ML setup functions
   461 (e.g. package initialization);
   462 
   463 * the distribution now includes Isabelle icons: see
   464 lib/logo/isabelle-{small,tiny}.xpm;
   465 
   466 * isatool install - install binaries with absolute references to
   467 ISABELLE_HOME/bin;
   468 
   469 * isatool logo -- create instances of the Isabelle logo (as EPS);
   470 
   471 * print mode 'emacs' reserved for Isamode;
   472 
   473 * support multiple print (ast) translations per constant name;
   474 
   475 * theorems involving oracles are now printed with a suffixed [!];
   476 
   477 
   478 *** HOL ***
   479 
   480 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   481 
   482 * HOL/inductive package reorganized and improved: now supports mutual
   483 definitions such as
   484 
   485   inductive EVEN ODD
   486     intrs
   487       null "0 : EVEN"
   488       oddI "n : EVEN ==> Suc n : ODD"
   489       evenI "n : ODD ==> Suc n : EVEN"
   490 
   491 new theorem list "elims" contains an elimination rule for each of the
   492 recursive sets; inductive definitions now handle disjunctive premises
   493 correctly (also ZF);
   494 
   495 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   496 "mutual_induct" no longer exists - the induction rule is always
   497 contained in "induct";
   498 
   499 
   500 * HOL/datatype package re-implemented and greatly improved: now
   501 supports mutually recursive datatypes such as
   502 
   503   datatype
   504     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   505             | SUM ('a aexp) ('a aexp)
   506             | DIFF ('a aexp) ('a aexp)
   507             | NUM 'a
   508   and
   509     'a bexp = LESS ('a aexp) ('a aexp)
   510             | AND ('a bexp) ('a bexp)
   511             | OR ('a bexp) ('a bexp)
   512 
   513 as well as indirectly recursive datatypes such as
   514 
   515   datatype
   516     ('a, 'b) term = Var 'a
   517                   | App 'b ((('a, 'b) term) list)
   518 
   519 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   520 induction on mutually / indirectly recursive datatypes.
   521 
   522 Primrec equations are now stored in theory and can be accessed via
   523 <function_name>.simps.
   524 
   525 INCOMPATIBILITIES:
   526 
   527   - Theories using datatypes must now have theory Datatype as an
   528     ancestor.
   529   - The specific <typename>.induct_tac no longer exists - use the
   530     generic induct_tac instead.
   531   - natE has been renamed to nat.exhaust - use exhaust_tac
   532     instead of res_inst_tac ... natE. Note that the variable
   533     names in nat.exhaust differ from the names in natE, this
   534     may cause some "fragile" proofs to fail.
   535   - The theorems split_<typename>_case and split_<typename>_case_asm
   536     have been renamed to <typename>.split and <typename>.split_asm.
   537   - Since default sorts of type variables are now handled correctly,
   538     some datatype definitions may have to be annotated with explicit
   539     sort constraints.
   540   - Primrec definitions no longer require function name and type
   541     of recursive argument.
   542 
   543 Consider using isatool fixdatatype to adapt your theories and proof
   544 scripts to the new package (backup your sources first!).
   545 
   546 
   547 * HOL/record package: considerably improved implementation; now
   548 includes concrete syntax for record types, terms, updates; theorems
   549 for surjective pairing and splitting !!-bound record variables; proof
   550 support is as follows:
   551 
   552   1) standard conversions (selectors or updates applied to record
   553 constructor terms) are part of the standard simpset;
   554 
   555   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   556 made part of standard simpset and claset via addIffs;
   557 
   558   3) a tactic for record field splitting (record_split_tac) is part of
   559 the standard claset (addSWrapper);
   560 
   561 To get a better idea about these rules you may retrieve them via
   562 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   563 the name of your record type.
   564 
   565 The split tactic 3) conceptually simplifies by the following rule:
   566 
   567   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   568 
   569 Thus any record variable that is bound by meta-all will automatically
   570 blow up into some record constructor term, consequently the
   571 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   572 solve record problems automatically.
   573 
   574 
   575 * reorganized the main HOL image: HOL/Integ and String loaded by
   576 default; theory Main includes everything;
   577 
   578 * automatic simplification of integer sums and comparisons, using cancellation;
   579 
   580 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   581 
   582 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   583 
   584 * many new identities for unions, intersections, set difference, etc.;
   585 
   586 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   587 called split_if, split_split, split_sum_case and split_nat_case (to go
   588 with add/delsplits);
   589 
   590 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   591 (?x::unit) = (); this is made part of the default simpset, which COULD
   592 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   593 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   594 unit_abs_eta_conv is added in order to counter the effect of
   595 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   596 %u.f();
   597 
   598 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   599 makes more sense);
   600 
   601 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   602   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   603   disjointness reasoning but breaking a few old proofs.
   604 
   605 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   606 to 'converse' from 'inverse' (for compatibility with ZF and some
   607 literature);
   608 
   609 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   610 the well-founded relation;
   611 
   612 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   613     Compl A.  The "Compl" syntax remains available as input syntax for this
   614     release ONLY.
   615 
   616 * HOL/Update: new theory of function updates:
   617     f(a:=b) == %x. if x=a then b else f x
   618 may also be iterated as in f(a:=b,c:=d,...);
   619 
   620 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   621 
   622 * HOL/List:
   623   - new function list_update written xs[i:=v] that updates the i-th
   624     list position. May also be iterated as in xs[i:=a,j:=b,...].
   625   - new function `upt' written [i..j(] which generates the list
   626     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   627     bound write [i..j], which is a shorthand for [i..j+1(].
   628   - new lexicographic orderings and corresponding wellfoundedness theorems.
   629 
   630 * HOL/Arith:
   631   - removed 'pred' (predecessor) function;
   632   - generalized some theorems about n-1;
   633   - many new laws about "div" and "mod";
   634   - new laws about greatest common divisors (see theory ex/Primes);
   635 
   636 * HOL/Relation: renamed the relational operator r^-1 "converse"
   637 instead of "inverse";
   638 
   639 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   640   of the multiset ordering;
   641 
   642 * directory HOL/Real: a construction of the reals using Dedekind cuts
   643   (not included by default);
   644 
   645 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   646 
   647 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   648   programs, i.e. different program variables may have different types.
   649 
   650 * calling (stac rew i) now fails if "rew" has no effect on the goal
   651   [previously, this check worked only if the rewrite rule was unconditional]
   652   Now rew can involve either definitions or equalities (either == or =).
   653 
   654 
   655 *** ZF ***
   656 
   657 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   658   only the theorems proved on ZF.ML;
   659 
   660 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   661   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   662   disjointness reasoning but breaking a few old proofs.
   663 
   664 * ZF/Update: new theory of function updates
   665     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   666   may also be iterated as in f(a:=b,c:=d,...);
   667 
   668 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   669 
   670 * calling (stac rew i) now fails if "rew" has no effect on the goal
   671   [previously, this check worked only if the rewrite rule was unconditional]
   672   Now rew can involve either definitions or equalities (either == or =).
   673 
   674 * case_tac provided for compatibility with HOL
   675     (like the old excluded_middle_tac, but with subgoals swapped)
   676 
   677 
   678 *** Internal programming interfaces ***
   679 
   680 * Pure: several new basic modules made available for general use, see
   681 also src/Pure/README;
   682 
   683 * improved the theory data mechanism to support encapsulation (data
   684 kind name replaced by private Object.kind, acting as authorization
   685 key); new type-safe user interface via functor TheoryDataFun; generic
   686 print_data function becomes basically useless;
   687 
   688 * removed global_names compatibility flag -- all theory declarations
   689 are qualified by default;
   690 
   691 * module Pure/Syntax now offers quote / antiquote translation
   692 functions (useful for Hoare logic etc. with implicit dependencies);
   693 see HOL/ex/Antiquote for an example use;
   694 
   695 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   696 cterm -> thm;
   697 
   698 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   699 subgoal;
   700 
   701 * Display.print_goals function moved to Locale.print_goals;
   702 
   703 * standard print function for goals supports current_goals_markers
   704 variable for marking begin of proof, end of proof, start of goal; the
   705 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   706 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   707 for example;
   708 
   709 
   710 
   711 New in Isabelle98 (January 1998)
   712 --------------------------------
   713 
   714 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   715 
   716 * changed lexical syntax of terms / types: dots made part of long
   717 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   718 
   719 * simpset (and claset) reference variable replaced by functions
   720 simpset / simpset_ref;
   721 
   722 * no longer supports theory aliases (via merge) and non-trivial
   723 implicit merge of thms' signatures;
   724 
   725 * most internal names of constants changed due to qualified names;
   726 
   727 * changed Pure/Sequence interface (see Pure/seq.ML);
   728 
   729 
   730 *** General Changes ***
   731 
   732 * hierachically structured name spaces (for consts, types, axms, thms
   733 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   734 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   735 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   736 long_names for fully qualified output names; NOTE: ML programs
   737 (special tactics, packages etc.) referring to internal names may have
   738 to be adapted to cope with fully qualified names; in case of severe
   739 backward campatibility problems try setting 'global_names' at compile
   740 time to have enrything declared within a flat name space; one may also
   741 fine tune name declarations in theories via the 'global' and 'local'
   742 section;
   743 
   744 * reimplemented the implicit simpset and claset using the new anytype
   745 data filed in signatures; references simpset:simpset ref etc. are
   746 replaced by functions simpset:unit->simpset and
   747 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   748 to patch your ML files accordingly;
   749 
   750 * HTML output now includes theory graph data for display with Java
   751 applet or isatool browser; data generated automatically via isatool
   752 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   753 
   754 * defs may now be conditional; improved rewrite_goals_tac to handle
   755 conditional equations;
   756 
   757 * defs now admits additional type arguments, using TYPE('a) syntax;
   758 
   759 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   760 creates a new theory node; implicit merge of thms' signatures is
   761 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   762 transfer:theory->thm->thm in (rare) cases;
   763 
   764 * improved handling of draft signatures / theories; draft thms (and
   765 ctyps, cterms) are automatically promoted to real ones;
   766 
   767 * slightly changed interfaces for oracles: admit many per theory, named
   768 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   769 
   770 * print_goals: optional output of const types (set show_consts and
   771 show_types);
   772 
   773 * improved output of warnings (###) and errors (***);
   774 
   775 * subgoal_tac displays a warning if the new subgoal has type variables;
   776 
   777 * removed old README and Makefiles;
   778 
   779 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   780 
   781 * removed obsolete init_pps and init_database;
   782 
   783 * deleted the obsolete tactical STATE, which was declared by
   784     fun STATE tacfun st = tacfun st st;
   785 
   786 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   787 (which abbreviates $HOME);
   788 
   789 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   790 use isatool fixseq to adapt your ML programs (this works for fully
   791 qualified references to the Sequence structure only!);
   792 
   793 * use_thy no longer requires writable current directory; it always
   794 reloads .ML *and* .thy file, if either one is out of date;
   795 
   796 
   797 *** Classical Reasoner ***
   798 
   799 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   800 tactics that use classical reasoning to simplify a subgoal without
   801 splitting it into several subgoals;
   802 
   803 * Safe_tac: like safe_tac but uses the default claset;
   804 
   805 
   806 *** Simplifier ***
   807 
   808 * added simplification meta rules:
   809     (asm_)(full_)simplify: simpset -> thm -> thm;
   810 
   811 * simplifier.ML no longer part of Pure -- has to be loaded by object
   812 logics (again);
   813 
   814 * added prems argument to simplification procedures;
   815 
   816 * HOL, FOL, ZF: added infix function `addsplits':
   817   instead of `<simpset> setloop (split_tac <thms>)'
   818   you can simply write `<simpset> addsplits <thms>'
   819 
   820 
   821 *** Syntax ***
   822 
   823 * TYPE('a) syntax for type reflection terms;
   824 
   825 * no longer handles consts with name "" -- declare as 'syntax' instead;
   826 
   827 * pretty printer: changed order of mixfix annotation preference (again!);
   828 
   829 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   830 
   831 
   832 *** HOL ***
   833 
   834 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   835   with `addloop' of the simplifier to faciliate case splitting in premises.
   836 
   837 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   838 
   839 * HOL/Auth: new protocol proofs including some for the Internet
   840   protocol TLS;
   841 
   842 * HOL/Map: new theory of `maps' a la VDM;
   843 
   844 * HOL/simplifier: simplification procedures nat_cancel_sums for
   845 cancelling out common nat summands from =, <, <= (in)equalities, or
   846 differences; simplification procedures nat_cancel_factor for
   847 cancelling common factor from =, <, <= (in)equalities over natural
   848 sums; nat_cancel contains both kinds of procedures, it is installed by
   849 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   850 
   851 * HOL/simplifier: terms of the form
   852   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   853   are rewritten to
   854   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   855   and those of the form
   856   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   857   are rewritten to
   858   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   859 
   860 * HOL/datatype
   861   Each datatype `t' now comes with a theorem `split_t_case' of the form
   862 
   863   P(t_case f1 ... fn x) =
   864      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   865         ...
   866        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   867      )
   868 
   869   and a theorem `split_t_case_asm' of the form
   870 
   871   P(t_case f1 ... fn x) =
   872     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   873         ...
   874        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   875      )
   876   which can be added to a simpset via `addsplits'. The existing theorems
   877   expand_list_case and expand_option_case have been renamed to
   878   split_list_case and split_option_case.
   879 
   880 * HOL/Arithmetic:
   881   - `pred n' is automatically converted to `n-1'.
   882     Users are strongly encouraged not to use `pred' any longer,
   883     because it will disappear altogether at some point.
   884   - Users are strongly encouraged to write "0 < n" rather than
   885     "n ~= 0". Theorems and proof tools have been modified towards this
   886     `standard'.
   887 
   888 * HOL/Lists:
   889   the function "set_of_list" has been renamed "set" (and its theorems too);
   890   the function "nth" now takes its arguments in the reverse order and
   891   has acquired the infix notation "!" as in "xs!n".
   892 
   893 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   894 
   895 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   896   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   897 
   898 * HOL/record: extensible records with schematic structural subtyping
   899 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   900 still lacks various theorems and concrete record syntax;
   901 
   902 
   903 *** HOLCF ***
   904 
   905 * removed "axioms" and "generated by" sections;
   906 
   907 * replaced "ops" section by extended "consts" section, which is capable of
   908   handling the continuous function space "->" directly;
   909 
   910 * domain package:
   911   . proves theorems immediately and stores them in the theory,
   912   . creates hierachical name space,
   913   . now uses normal mixfix annotations (instead of cinfix...),
   914   . minor changes to some names and values (for consistency),
   915   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   916   . separator between mutual domain defs: changed "," to "and",
   917   . improved handling of sort constraints;  now they have to
   918     appear on the left-hand side of the equations only;
   919 
   920 * fixed LAM <x,y,zs>.b syntax;
   921 
   922 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   923 adm (%x. P (t x)), where P is chainfinite and t continuous;
   924 
   925 
   926 *** FOL and ZF ***
   927 
   928 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   929   with `addloop' of the simplifier to faciliate case splitting in premises.
   930 
   931 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   932 in HOL, they strip ALL and --> from proved theorems;
   933 
   934 
   935 
   936 New in Isabelle94-8 (May 1997)
   937 ------------------------------
   938 
   939 *** General Changes ***
   940 
   941 * new utilities to build / run / maintain Isabelle etc. (in parts
   942 still somewhat experimental); old Makefiles etc. still functional;
   943 
   944 * new 'Isabelle System Manual';
   945 
   946 * INSTALL text, together with ./configure and ./build scripts;
   947 
   948 * reimplemented type inference for greater efficiency, better error
   949 messages and clean internal interface;
   950 
   951 * prlim command for dealing with lots of subgoals (an easier way of
   952 setting goals_limit);
   953 
   954 
   955 *** Syntax ***
   956 
   957 * supports alternative (named) syntax tables (parser and pretty
   958 printer); internal interface is provided by add_modesyntax(_i);
   959 
   960 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   961 be used in conjunction with the Isabelle symbol font; uses the
   962 "symbols" syntax table;
   963 
   964 * added token_translation interface (may translate name tokens in
   965 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   966 the current print_mode); IMPORTANT: user print translation functions
   967 are responsible for marking newly introduced bounds
   968 (Syntax.mark_boundT);
   969 
   970 * token translations for modes "xterm" and "xterm_color" that display
   971 names in bold, underline etc. or colors (which requires a color
   972 version of xterm);
   973 
   974 * infixes may now be declared with names independent of their syntax;
   975 
   976 * added typed_print_translation (like print_translation, but may
   977 access type of constant);
   978 
   979 
   980 *** Classical Reasoner ***
   981 
   982 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   983 some limitations.  Blast_tac...
   984   + ignores addss, addbefore, addafter; this restriction is intrinsic
   985   + ignores elimination rules that don't have the correct format
   986         (the conclusion MUST be a formula variable)
   987   + ignores types, which can make HOL proofs fail
   988   + rules must not require higher-order unification, e.g. apply_type in ZF
   989     [message "Function Var's argument not a bound variable" relates to this]
   990   + its proof strategy is more general but can actually be slower
   991 
   992 * substitution with equality assumptions no longer permutes other
   993 assumptions;
   994 
   995 * minor changes in semantics of addafter (now called addaltern); renamed
   996 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   997 (and access functions for it);
   998 
   999 * improved combination of classical reasoner and simplifier:
  1000   + functions for handling clasimpsets
  1001   + improvement of addss: now the simplifier is called _after_ the
  1002     safe steps.
  1003   + safe variant of addss called addSss: uses safe simplifications
  1004     _during_ the safe steps. It is more complete as it allows multiple
  1005     instantiations of unknowns (e.g. with slow_tac).
  1006 
  1007 *** Simplifier ***
  1008 
  1009 * added interface for simplification procedures (functions that
  1010 produce *proven* rewrite rules on the fly, depending on current
  1011 redex);
  1012 
  1013 * ordering on terms as parameter (used for ordered rewriting);
  1014 
  1015 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1016 
  1017 * the solver is now split into a safe and an unsafe part.
  1018 This should be invisible for the normal user, except that the
  1019 functions setsolver and addsolver have been renamed to setSolver and
  1020 addSolver; added safe_asm_full_simp_tac;
  1021 
  1022 
  1023 *** HOL ***
  1024 
  1025 * a generic induction tactic `induct_tac' which works for all datatypes and
  1026 also for type `nat';
  1027 
  1028 * a generic case distinction tactic `exhaust_tac' which works for all
  1029 datatypes and also for type `nat';
  1030 
  1031 * each datatype comes with a function `size';
  1032 
  1033 * patterns in case expressions allow tuple patterns as arguments to
  1034 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1035 
  1036 * primrec now also works with type nat;
  1037 
  1038 * recdef: a new declaration form, allows general recursive functions to be
  1039 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1040 
  1041 * the constant for negation has been renamed from "not" to "Not" to
  1042 harmonize with FOL, ZF, LK, etc.;
  1043 
  1044 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1045 infinite lists;
  1046 
  1047 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1048 
  1049 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1050 problems in commutative rings, using axiomatic type classes for + and *;
  1051 
  1052 * more examples in HOL/MiniML and HOL/Auth;
  1053 
  1054 * more default rewrite rules for quantifiers, union/intersection;
  1055 
  1056 * a new constant `arbitrary == @x.False';
  1057 
  1058 * HOLCF/IOA replaces old HOL/IOA;
  1059 
  1060 * HOLCF changes: derived all rules and arities
  1061   + axiomatic type classes instead of classes
  1062   + typedef instead of faking type definitions
  1063   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1064   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1065   + eliminated the types void, one, tr
  1066   + use unit lift and bool lift (with translations) instead of one and tr
  1067   + eliminated blift from Lift3.thy (use Def instead of blift)
  1068   all eliminated rules are derived as theorems --> no visible changes ;
  1069 
  1070 
  1071 *** ZF ***
  1072 
  1073 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1074 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1075 as ZF_cs addSIs [equalityI];
  1076 
  1077 
  1078 
  1079 New in Isabelle94-7 (November 96)
  1080 ---------------------------------
  1081 
  1082 * allowing negative levels (as offsets) in prlev and choplev;
  1083 
  1084 * super-linear speedup for large simplifications;
  1085 
  1086 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1087 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1088 FAIL); can suppress it using the command Delsimps (ex_simps @
  1089 all_simps); De Morgan laws are also now included, by default;
  1090 
  1091 * improved printing of ==>  :  ~:
  1092 
  1093 * new object-logic "Sequents" adds linear logic, while replacing LK
  1094 and Modal (thanks to Sara Kalvala);
  1095 
  1096 * HOL/Auth: correctness proofs for authentication protocols;
  1097 
  1098 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1099 examples on HOL/Auth);
  1100 
  1101 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1102 the rewriter and classical reasoner simultaneously;
  1103 
  1104 * function uresult no longer returns theorems in "standard" format;
  1105 regain previous version by: val uresult = standard o uresult;
  1106 
  1107 
  1108 
  1109 New in Isabelle94-6
  1110 -------------------
  1111 
  1112 * oracles -- these establish an interface between Isabelle and trusted
  1113 external reasoners, which may deliver results as theorems;
  1114 
  1115 * proof objects (in particular record all uses of oracles);
  1116 
  1117 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1118 
  1119 * "constdefs" section in theory files;
  1120 
  1121 * "primrec" section (HOL) no longer requires names;
  1122 
  1123 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1124 
  1125 
  1126 
  1127 New in Isabelle94-5
  1128 -------------------
  1129 
  1130 * reduced space requirements;
  1131 
  1132 * automatic HTML generation from theories;
  1133 
  1134 * theory files no longer require "..." (quotes) around most types;
  1135 
  1136 * new examples, including two proofs of the Church-Rosser theorem;
  1137 
  1138 * non-curried (1994) version of HOL is no longer distributed;
  1139 
  1140 
  1141 
  1142 New in Isabelle94-4
  1143 -------------------
  1144 
  1145 * greatly reduced space requirements;
  1146 
  1147 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1148 
  1149 * searchable theorem database (see the section "Retrieving theorems" on
  1150 page 8 of the Reference Manual);
  1151 
  1152 * new examples, including Grabczewski's monumental case study of the
  1153 Axiom of Choice;
  1154 
  1155 * The previous version of HOL renamed to Old_HOL;
  1156 
  1157 * The new version of HOL (previously called CHOL) uses a curried syntax
  1158 for functions.  Application looks like f a b instead of f(a,b);
  1159 
  1160 * Mutually recursive inductive definitions finally work in HOL;
  1161 
  1162 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1163 translates to the operator "split";
  1164 
  1165 
  1166 
  1167 New in Isabelle94-3
  1168 -------------------
  1169 
  1170 * new infix operator, addss, allowing the classical reasoner to
  1171 perform simplification at each step of its search.  Example:
  1172         fast_tac (cs addss ss)
  1173 
  1174 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1175 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1176 look like (a,b) instead of <a,b>;
  1177 
  1178 * PLEASE NOTE: CHOL will eventually replace HOL!
  1179 
  1180 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1181 It translates to the operator "split".  A new theory of integers is available;
  1182 
  1183 * In ZF, integer numerals now denote two's-complement binary integers.
  1184 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1185 
  1186 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1187 of the Axiom of Choice;
  1188 
  1189 
  1190 
  1191 New in Isabelle94-2
  1192 -------------------
  1193 
  1194 * Significantly faster resolution;
  1195 
  1196 * the different sections in a .thy file can now be mixed and repeated
  1197 freely;
  1198 
  1199 * Database of theorems for FOL, HOL and ZF.  New
  1200 commands including qed, qed_goal and bind_thm store theorems in the database.
  1201 
  1202 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1203 a given theory (thms_of), or find out what theory a theorem was proved in
  1204 (theory_of_thm);
  1205 
  1206 * Bugs fixed in the inductive definition and datatype packages;
  1207 
  1208 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1209 and HOL_dup_cs obsolete;
  1210 
  1211 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1212 have been removed;
  1213 
  1214 * Simpler definition of function space in ZF;
  1215 
  1216 * new results about cardinal and ordinal arithmetic in ZF;
  1217 
  1218 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1219 types;
  1220 
  1221 
  1222 $Id$