NEWS
author wenzelm
Sat Feb 05 16:54:27 2000 +0100 (2000-02-05)
changeset 8195 af2575a5c5ae
parent 8184 6b7ef9fc39da
child 8203 2fcc6017cb72
permissions -rw-r--r--
'.' == by this;
     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, assumptions etc. may be natural numbers as well;
    16 
    17 * new 'obtain' language element supports generalized existence proofs;
    18 
    19 
    20 *** HOL ***
    21 
    22 * Algebra: new theory of rings and univariate polynomials, by Clemens
    23 Ballarin;
    24 
    25 
    26 
    27 New in Isabelle99 (October 1999)
    28 --------------------------------
    29 
    30 *** Overview of INCOMPATIBILITIES (see below for more details) ***
    31 
    32 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
    33 are no longer simplified.  (This allows the simplifier to unfold recursive
    34 functional programs.)  To restore the old behaviour, declare
    35 
    36     Delcongs [if_weak_cong];
    37 
    38 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    39 complement;
    40 
    41 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    42 
    43 * HOL/datatype: mutual_induct_tac no longer exists --
    44   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
    45 
    46 * HOL/typedef: fixed type inference for representing set; type
    47 arguments now have to occur explicitly on the rhs as type constraints;
    48 
    49 * ZF: The con_defs part of an inductive definition may no longer refer
    50 to constants declared in the same theory;
    51 
    52 * HOL, ZF: the function mk_cases, generated by the inductive
    53 definition package, has lost an argument.  To simplify its result, it
    54 uses the default simpset instead of a supplied list of theorems.
    55 
    56 * HOL/List: the constructors of type list are now Nil and Cons;
    57 
    58 * Simplifier: the type of the infix ML functions
    59 	setSSolver addSSolver setSolver addSolver
    60 is now  simpset * solver -> simpset  where `solver' is a new abstract type
    61 for packaging solvers. A solver is created via
    62 	mk_solver: string -> (thm list -> int -> tactic) -> solver
    63 where the string argument is only a comment.
    64 
    65 
    66 *** Proof tools ***
    67 
    68 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
    69 decision procedure for linear arithmetic. Currently it is used for
    70 types `nat', `int', and `real' in HOL (see below); it can, should and
    71 will be instantiated for other types and logics as well.
    72 
    73 * The simplifier now accepts rewrite rules with flexible heads, eg
    74      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
    75   They are applied like any rule with a non-pattern lhs, i.e. by first-order
    76   matching.
    77 
    78 
    79 *** General ***
    80 
    81 * New Isabelle/Isar subsystem provides an alternative to traditional
    82 tactical theorem proving; together with the ProofGeneral/isar user
    83 interface it offers an interactive environment for developing human
    84 readable proof documents (Isar == Intelligible semi-automated
    85 reasoning); for further information see isatool doc isar-ref,
    86 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
    87 
    88 * improved presentation of theories: better HTML markup (including
    89 colors), graph views in several sizes; isatool usedir now provides a
    90 proper interface for user theories (via -P option); actual document
    91 preparation based on (PDF)LaTeX is available as well (for new-style
    92 theories only); see isatool doc system for more information;
    93 
    94 * native support for Proof General, both for classic Isabelle and
    95 Isabelle/Isar;
    96 
    97 * ML function thm_deps visualizes dependencies of theorems and lemmas,
    98 using the graph browser tool;
    99 
   100 * Isabelle manuals now also available as PDF;
   101 
   102 * theory loader rewritten from scratch (may not be fully
   103 bug-compatible); old loadpath variable has been replaced by show_path,
   104 add_path, del_path, reset_path functions; new operations such as
   105 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   106 isatool doc ref);
   107 
   108 * improved isatool install: option -k creates KDE application icon,
   109 option -p DIR installs standalone binaries;
   110 
   111 * added ML_PLATFORM setting (useful for cross-platform installations);
   112 more robust handling of platform specific ML images for SML/NJ;
   113 
   114 * the settings environment is now statically scoped, i.e. it is never
   115 created again in sub-processes invoked from isabelle, isatool, or
   116 Isabelle;
   117 
   118 * path element specification '~~' refers to '$ISABELLE_HOME';
   119 
   120 * in locales, the "assumes" and "defines" parts may be omitted if
   121 empty;
   122 
   123 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   124 long arrows);
   125 
   126 * new print_mode "HTML";
   127 
   128 * new flag show_tags controls display of tags of theorems (which are
   129 basically just comments that may be attached by some tools);
   130 
   131 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   132 mode and goal output format:
   133 
   134 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   135 244c244
   136 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   137 ---
   138 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   139 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   140 181c181
   141 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   142 ---
   143 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   144 
   145 * function bind_thms stores lists of theorems (cf. bind_thm);
   146 
   147 * new shorthand tactics ftac, eatac, datac, fatac;
   148 
   149 * qed (and friends) now accept "" as result name; in that case the
   150 theorem is not stored, but proper checks and presentation of the
   151 result still apply;
   152 
   153 * theorem database now also indexes constants "Trueprop", "all",
   154 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   155 
   156 
   157 *** HOL ***
   158 
   159 ** HOL arithmetic **
   160 
   161 * There are now decision procedures for linear arithmetic over nat and
   162 int:
   163 
   164 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   165 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   166 are treated as atomic; subformulae not involving type `nat' or `int'
   167 are ignored; quantified subformulae are ignored unless they are
   168 positive universal or negative existential. The tactic has to be
   169 invoked by hand and can be a little bit slow. In particular, the
   170 running time is exponential in the number of occurrences of `min' and
   171 `max', and `-' on `nat'.
   172 
   173 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   174 (negated) (in)equalities among the premises and the conclusion into
   175 account (i.e. no compound formulae) and does not know about `min' and
   176 `max', and `-' on `nat'. It is fast and is used automatically by the
   177 simplifier.
   178 
   179 NB: At the moment, these decision procedures do not cope with mixed
   180 nat/int formulae where the two parts interact, such as `m < n ==>
   181 int(m) < int(n)'.
   182 
   183 * HOL/Numeral provides a generic theory of numerals (encoded
   184 efficiently as bit strings); setup for types nat/int/real is in place;
   185 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   186 int, existing theories and proof scripts may require a few additional
   187 type constraints;
   188 
   189 * integer division and remainder can now be performed on constant
   190 arguments;
   191 
   192 * many properties of integer multiplication, division and remainder
   193 are now available;
   194 
   195 * An interface to the Stanford Validity Checker (SVC) is available through the
   196 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   197 are proved automatically.  SVC must be installed separately, and its results
   198 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   199 invocation of the underlying oracle).  For SVC see
   200   http://verify.stanford.edu/SVC
   201 
   202 * IsaMakefile: the HOL-Real target now builds an actual image;
   203 
   204 
   205 ** HOL misc **
   206 
   207 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   208 (in Isabelle/Isar) -- by Gertrud Bauer;
   209 
   210 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   211 analysis for assembly languages with subtypes;
   212 
   213 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   214 -- avoids syntactic ambiguities and treats state, transition, and
   215 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   216 changed syntax and (many) tactics;
   217 
   218 * HOL/inductive: Now also handles more general introduction rules such
   219   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   220   theorems are now maintained within the theory (maintained via the
   221   "mono" attribute);
   222 
   223 * HOL/datatype: Now also handles arbitrarily branching datatypes
   224   (using function types) such as
   225 
   226   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   227 
   228 * HOL/record: record_simproc (part of the default simpset) takes care
   229 of selectors applied to updated records; record_split_tac is no longer
   230 part of the default claset; update_defs may now be removed from the
   231 simpset in many cases; COMPATIBILITY: old behavior achieved by
   232 
   233   claset_ref () := claset() addSWrapper record_split_wrapper;
   234   Delsimprocs [record_simproc]
   235 
   236 * HOL/typedef: fixed type inference for representing set; type
   237 arguments now have to occur explicitly on the rhs as type constraints;
   238 
   239 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   240 names rather than an ML expression;
   241 
   242 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   243 supplied later.  Program schemes can be defined, such as
   244     "While B C s = (if B s then While B C (C s) else s)"
   245 where the well-founded relation can be chosen after B and C have been given.
   246 
   247 * HOL/List: the constructors of type list are now Nil and Cons;
   248 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   249 course, ML tools referring to List.list.op # etc. have to be adapted;
   250 
   251 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   252 disabled by default; run isabelle with option -m HOL to get back to
   253 the original Gordon/HOL-style output;
   254 
   255 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   256 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   257 
   258 * HOL basic syntax simplified (more orthogonal): all variants of
   259 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   260 Eps operator is provided as well: "SOME x. P[x]";
   261 
   262 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   263 
   264 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   265 thus available for user theories;
   266 
   267 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   268 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   269 time;
   270 
   271 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   272 several times and then mp;
   273 
   274 
   275 *** LK ***
   276 
   277 * the notation <<...>> is now available as a notation for sequences of
   278 formulas;
   279 
   280 * the simplifier is now installed
   281 
   282 * the axiom system has been generalized (thanks to Soren Heilmann) 
   283 
   284 * the classical reasoner now has a default rule database
   285 
   286 
   287 *** ZF ***
   288 
   289 * new primrec section allows primitive recursive functions to be given
   290 directly (as in HOL) over datatypes and the natural numbers;
   291 
   292 * new tactics induct_tac and exhaust_tac for induction (or case
   293 analysis) over datatypes and the natural numbers;
   294 
   295 * the datatype declaration of type T now defines the recursor T_rec;
   296 
   297 * simplification automatically does freeness reasoning for datatype
   298 constructors;
   299 
   300 * automatic type-inference, with AddTCs command to insert new
   301 type-checking rules;
   302 
   303 * datatype introduction rules are now added as Safe Introduction rules
   304 to the claset;
   305 
   306 * the syntax "if P then x else y" is now available in addition to
   307 if(P,x,y);
   308 
   309 
   310 *** Internal programming interfaces ***
   311 
   312 * tuned simplifier trace output; new flag debug_simp;
   313 
   314 * structures Vartab / Termtab (instances of TableFun) offer efficient
   315 tables indexed by indexname_ord / term_ord (compatible with aconv);
   316 
   317 * AxClass.axclass_tac lost the theory argument;
   318 
   319 * tuned current_goals_markers semantics: begin / end goal avoids
   320 printing empty lines;
   321 
   322 * removed prs and prs_fn hook, which was broken because it did not
   323 include \n in its semantics, forcing writeln to add one
   324 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   325 string -> unit if you really want to output text without newline;
   326 
   327 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   328 plain output, interface builders may have to enable 'isabelle_font'
   329 mode to get Isabelle font glyphs as before;
   330 
   331 * refined token_translation interface; INCOMPATIBILITY: output length
   332 now of type real instead of int;
   333 
   334 * theory loader actions may be traced via new ThyInfo.add_hook
   335 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   336 your own database of information attached to *whole* theories -- as
   337 opposed to intra-theory data slots offered via TheoryDataFun;
   338 
   339 * proper handling of dangling sort hypotheses (at last!);
   340 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   341 extra sort hypotheses that can be witnessed from the type signature;
   342 the force_strip_shyps flag is gone, any remaining shyps are simply
   343 left in the theorem (with a warning issued by strip_shyps_warning);
   344 
   345 
   346 
   347 New in Isabelle98-1 (October 1998)
   348 ----------------------------------
   349 
   350 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   351 
   352 * several changes of automated proof tools;
   353 
   354 * HOL: major changes to the inductive and datatype packages, including
   355 some minor incompatibilities of theory syntax;
   356 
   357 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   358 called `inj_on';
   359 
   360 * HOL: removed duplicate thms in Arith:
   361   less_imp_add_less  should be replaced by  trans_less_add1
   362   le_imp_add_le      should be replaced by  trans_le_add1
   363 
   364 * HOL: unary minus is now overloaded (new type constraints may be
   365 required);
   366 
   367 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   368 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   369 now taken as an integer constant.
   370 
   371 * Pure: ML function 'theory_of' renamed to 'theory';
   372 
   373 
   374 *** Proof tools ***
   375 
   376 * Simplifier:
   377   1. Asm_full_simp_tac is now more aggressive.
   378      1. It will sometimes reorient premises if that increases their power to
   379         simplify.
   380      2. It does no longer proceed strictly from left to right but may also
   381         rotate premises to achieve further simplification.
   382      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   383      old Asm_full_simp_tac in that it does not rotate premises.
   384   2. The simplifier now knows a little bit about nat-arithmetic.
   385 
   386 * Classical reasoner: wrapper mechanism for the classical reasoner now
   387 allows for selected deletion of wrappers, by introduction of names for
   388 wrapper functionals.  This implies that addbefore, addSbefore,
   389 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   390 and that adding two tactics with the same name overwrites the first
   391 one (emitting a warning).
   392   type wrapper = (int -> tactic) -> (int -> tactic)
   393   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   394   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   395   delWrapper, delSWrapper: claset *  string            -> claset
   396   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   397 
   398 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   399 semantics; addbefore now affects only the unsafe part of step_tac
   400 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   401 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   402 by Force_tac;
   403 
   404 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   405 compWrapper; added safe wrapper (and access functions for it);
   406 
   407 * HOL/split_all_tac is now much faster and fails if there is nothing
   408 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   409 and the names of the automatically generated variables have changed.
   410 split_all_tac has moved within claset() from unsafe wrappers to safe
   411 wrappers, which means that !!-bound variables are split much more
   412 aggressively, and safe_tac and clarify_tac now split such variables.
   413 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   414 Note: the same holds for record_split_tac, which does the job of
   415 split_all_tac for record fields.
   416 
   417 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   418 permanently to the default simpset using Addsplits just like
   419 Addsimps. They can be removed via Delsplits just like
   420 Delsimps. Lower-case versions are also available.
   421 
   422 * HOL/Simplifier: The rule split_if is now part of the default
   423 simpset. This means that the simplifier will eliminate all occurrences
   424 of if-then-else in the conclusion of a goal. To prevent this, you can
   425 either remove split_if completely from the default simpset by
   426 `Delsplits [split_if]' or remove it in a specific call of the
   427 simplifier using `... delsplits [split_if]'.  You can also add/delete
   428 other case splitting rules to/from the default simpset: every datatype
   429 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   430 t is the name of the datatype).
   431 
   432 * Classical reasoner / Simplifier combination: new force_tac (and
   433 derivatives Force_tac, force) combines rewriting and classical
   434 reasoning (and whatever other tools) similarly to auto_tac, but is
   435 aimed to solve the given subgoal completely.
   436 
   437 
   438 *** General ***
   439 
   440 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   441 and `goalw': the theory is no longer needed as an explicit argument -
   442 the current theory context is used; assumptions are no longer returned
   443 at the ML-level unless one of them starts with ==> or !!; it is
   444 recommended to convert to these new commands using isatool fixgoal
   445 (backup your sources first!);
   446 
   447 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   448 the current theory context, and 'theory' to lookup stored theories;
   449 
   450 * new theory section 'locale' for declaring constants, assumptions and
   451 definitions that have local scope;
   452 
   453 * new theory section 'nonterminals' for purely syntactic types;
   454 
   455 * new theory section 'setup' for generic ML setup functions
   456 (e.g. package initialization);
   457 
   458 * the distribution now includes Isabelle icons: see
   459 lib/logo/isabelle-{small,tiny}.xpm;
   460 
   461 * isatool install - install binaries with absolute references to
   462 ISABELLE_HOME/bin;
   463 
   464 * isatool logo -- create instances of the Isabelle logo (as EPS);
   465 
   466 * print mode 'emacs' reserved for Isamode;
   467 
   468 * support multiple print (ast) translations per constant name;
   469 
   470 * theorems involving oracles are now printed with a suffixed [!];
   471 
   472 
   473 *** HOL ***
   474 
   475 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   476 
   477 * HOL/inductive package reorganized and improved: now supports mutual
   478 definitions such as
   479 
   480   inductive EVEN ODD
   481     intrs
   482       null "0 : EVEN"
   483       oddI "n : EVEN ==> Suc n : ODD"
   484       evenI "n : ODD ==> Suc n : EVEN"
   485 
   486 new theorem list "elims" contains an elimination rule for each of the
   487 recursive sets; inductive definitions now handle disjunctive premises
   488 correctly (also ZF);
   489 
   490 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   491 "mutual_induct" no longer exists - the induction rule is always
   492 contained in "induct";
   493 
   494 
   495 * HOL/datatype package re-implemented and greatly improved: now
   496 supports mutually recursive datatypes such as
   497 
   498   datatype
   499     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   500             | SUM ('a aexp) ('a aexp)
   501             | DIFF ('a aexp) ('a aexp)
   502             | NUM 'a
   503   and
   504     'a bexp = LESS ('a aexp) ('a aexp)
   505             | AND ('a bexp) ('a bexp)
   506             | OR ('a bexp) ('a bexp)
   507 
   508 as well as indirectly recursive datatypes such as
   509 
   510   datatype
   511     ('a, 'b) term = Var 'a
   512                   | App 'b ((('a, 'b) term) list)
   513 
   514 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   515 induction on mutually / indirectly recursive datatypes.
   516 
   517 Primrec equations are now stored in theory and can be accessed via
   518 <function_name>.simps.
   519 
   520 INCOMPATIBILITIES:
   521 
   522   - Theories using datatypes must now have theory Datatype as an
   523     ancestor.
   524   - The specific <typename>.induct_tac no longer exists - use the
   525     generic induct_tac instead.
   526   - natE has been renamed to nat.exhaust - use exhaust_tac
   527     instead of res_inst_tac ... natE. Note that the variable
   528     names in nat.exhaust differ from the names in natE, this
   529     may cause some "fragile" proofs to fail.
   530   - The theorems split_<typename>_case and split_<typename>_case_asm
   531     have been renamed to <typename>.split and <typename>.split_asm.
   532   - Since default sorts of type variables are now handled correctly,
   533     some datatype definitions may have to be annotated with explicit
   534     sort constraints.
   535   - Primrec definitions no longer require function name and type
   536     of recursive argument.
   537 
   538 Consider using isatool fixdatatype to adapt your theories and proof
   539 scripts to the new package (backup your sources first!).
   540 
   541 
   542 * HOL/record package: considerably improved implementation; now
   543 includes concrete syntax for record types, terms, updates; theorems
   544 for surjective pairing and splitting !!-bound record variables; proof
   545 support is as follows:
   546 
   547   1) standard conversions (selectors or updates applied to record
   548 constructor terms) are part of the standard simpset;
   549 
   550   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   551 made part of standard simpset and claset via addIffs;
   552 
   553   3) a tactic for record field splitting (record_split_tac) is part of
   554 the standard claset (addSWrapper);
   555 
   556 To get a better idea about these rules you may retrieve them via
   557 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   558 the name of your record type.
   559 
   560 The split tactic 3) conceptually simplifies by the following rule:
   561 
   562   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   563 
   564 Thus any record variable that is bound by meta-all will automatically
   565 blow up into some record constructor term, consequently the
   566 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   567 solve record problems automatically.
   568 
   569 
   570 * reorganized the main HOL image: HOL/Integ and String loaded by
   571 default; theory Main includes everything;
   572 
   573 * automatic simplification of integer sums and comparisons, using cancellation;
   574 
   575 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   576 
   577 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   578 
   579 * many new identities for unions, intersections, set difference, etc.;
   580 
   581 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   582 called split_if, split_split, split_sum_case and split_nat_case (to go
   583 with add/delsplits);
   584 
   585 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   586 (?x::unit) = (); this is made part of the default simpset, which COULD
   587 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   588 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   589 unit_abs_eta_conv is added in order to counter the effect of
   590 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   591 %u.f();
   592 
   593 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   594 makes more sense);
   595 
   596 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   597   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   598   disjointness reasoning but breaking a few old proofs.
   599 
   600 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   601 to 'converse' from 'inverse' (for compatibility with ZF and some
   602 literature);
   603 
   604 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   605 the well-founded relation;
   606 
   607 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   608     Compl A.  The "Compl" syntax remains available as input syntax for this
   609     release ONLY.
   610 
   611 * HOL/Update: new theory of function updates:
   612     f(a:=b) == %x. if x=a then b else f x
   613 may also be iterated as in f(a:=b,c:=d,...);
   614 
   615 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   616 
   617 * HOL/List:
   618   - new function list_update written xs[i:=v] that updates the i-th
   619     list position. May also be iterated as in xs[i:=a,j:=b,...].
   620   - new function `upt' written [i..j(] which generates the list
   621     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   622     bound write [i..j], which is a shorthand for [i..j+1(].
   623   - new lexicographic orderings and corresponding wellfoundedness theorems.
   624 
   625 * HOL/Arith:
   626   - removed 'pred' (predecessor) function;
   627   - generalized some theorems about n-1;
   628   - many new laws about "div" and "mod";
   629   - new laws about greatest common divisors (see theory ex/Primes);
   630 
   631 * HOL/Relation: renamed the relational operator r^-1 "converse"
   632 instead of "inverse";
   633 
   634 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   635   of the multiset ordering;
   636 
   637 * directory HOL/Real: a construction of the reals using Dedekind cuts
   638   (not included by default);
   639 
   640 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   641 
   642 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   643   programs, i.e. different program variables may have different types.
   644 
   645 * calling (stac rew i) now fails if "rew" has no effect on the goal
   646   [previously, this check worked only if the rewrite rule was unconditional]
   647   Now rew can involve either definitions or equalities (either == or =).
   648 
   649 
   650 *** ZF ***
   651 
   652 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   653   only the theorems proved on ZF.ML;
   654 
   655 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   656   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   657   disjointness reasoning but breaking a few old proofs.
   658 
   659 * ZF/Update: new theory of function updates
   660     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   661   may also be iterated as in f(a:=b,c:=d,...);
   662 
   663 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   664 
   665 * calling (stac rew i) now fails if "rew" has no effect on the goal
   666   [previously, this check worked only if the rewrite rule was unconditional]
   667   Now rew can involve either definitions or equalities (either == or =).
   668 
   669 * case_tac provided for compatibility with HOL
   670     (like the old excluded_middle_tac, but with subgoals swapped)
   671 
   672 
   673 *** Internal programming interfaces ***
   674 
   675 * Pure: several new basic modules made available for general use, see
   676 also src/Pure/README;
   677 
   678 * improved the theory data mechanism to support encapsulation (data
   679 kind name replaced by private Object.kind, acting as authorization
   680 key); new type-safe user interface via functor TheoryDataFun; generic
   681 print_data function becomes basically useless;
   682 
   683 * removed global_names compatibility flag -- all theory declarations
   684 are qualified by default;
   685 
   686 * module Pure/Syntax now offers quote / antiquote translation
   687 functions (useful for Hoare logic etc. with implicit dependencies);
   688 see HOL/ex/Antiquote for an example use;
   689 
   690 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   691 cterm -> thm;
   692 
   693 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   694 subgoal;
   695 
   696 * Display.print_goals function moved to Locale.print_goals;
   697 
   698 * standard print function for goals supports current_goals_markers
   699 variable for marking begin of proof, end of proof, start of goal; the
   700 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   701 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   702 for example;
   703 
   704 
   705 
   706 New in Isabelle98 (January 1998)
   707 --------------------------------
   708 
   709 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   710 
   711 * changed lexical syntax of terms / types: dots made part of long
   712 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   713 
   714 * simpset (and claset) reference variable replaced by functions
   715 simpset / simpset_ref;
   716 
   717 * no longer supports theory aliases (via merge) and non-trivial
   718 implicit merge of thms' signatures;
   719 
   720 * most internal names of constants changed due to qualified names;
   721 
   722 * changed Pure/Sequence interface (see Pure/seq.ML);
   723 
   724 
   725 *** General Changes ***
   726 
   727 * hierachically structured name spaces (for consts, types, axms, thms
   728 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   729 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   730 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   731 long_names for fully qualified output names; NOTE: ML programs
   732 (special tactics, packages etc.) referring to internal names may have
   733 to be adapted to cope with fully qualified names; in case of severe
   734 backward campatibility problems try setting 'global_names' at compile
   735 time to have enrything declared within a flat name space; one may also
   736 fine tune name declarations in theories via the 'global' and 'local'
   737 section;
   738 
   739 * reimplemented the implicit simpset and claset using the new anytype
   740 data filed in signatures; references simpset:simpset ref etc. are
   741 replaced by functions simpset:unit->simpset and
   742 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   743 to patch your ML files accordingly;
   744 
   745 * HTML output now includes theory graph data for display with Java
   746 applet or isatool browser; data generated automatically via isatool
   747 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   748 
   749 * defs may now be conditional; improved rewrite_goals_tac to handle
   750 conditional equations;
   751 
   752 * defs now admits additional type arguments, using TYPE('a) syntax;
   753 
   754 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   755 creates a new theory node; implicit merge of thms' signatures is
   756 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   757 transfer:theory->thm->thm in (rare) cases;
   758 
   759 * improved handling of draft signatures / theories; draft thms (and
   760 ctyps, cterms) are automatically promoted to real ones;
   761 
   762 * slightly changed interfaces for oracles: admit many per theory, named
   763 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   764 
   765 * print_goals: optional output of const types (set show_consts and
   766 show_types);
   767 
   768 * improved output of warnings (###) and errors (***);
   769 
   770 * subgoal_tac displays a warning if the new subgoal has type variables;
   771 
   772 * removed old README and Makefiles;
   773 
   774 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   775 
   776 * removed obsolete init_pps and init_database;
   777 
   778 * deleted the obsolete tactical STATE, which was declared by
   779     fun STATE tacfun st = tacfun st st;
   780 
   781 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   782 (which abbreviates $HOME);
   783 
   784 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   785 use isatool fixseq to adapt your ML programs (this works for fully
   786 qualified references to the Sequence structure only!);
   787 
   788 * use_thy no longer requires writable current directory; it always
   789 reloads .ML *and* .thy file, if either one is out of date;
   790 
   791 
   792 *** Classical Reasoner ***
   793 
   794 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   795 tactics that use classical reasoning to simplify a subgoal without
   796 splitting it into several subgoals;
   797 
   798 * Safe_tac: like safe_tac but uses the default claset;
   799 
   800 
   801 *** Simplifier ***
   802 
   803 * added simplification meta rules:
   804     (asm_)(full_)simplify: simpset -> thm -> thm;
   805 
   806 * simplifier.ML no longer part of Pure -- has to be loaded by object
   807 logics (again);
   808 
   809 * added prems argument to simplification procedures;
   810 
   811 * HOL, FOL, ZF: added infix function `addsplits':
   812   instead of `<simpset> setloop (split_tac <thms>)'
   813   you can simply write `<simpset> addsplits <thms>'
   814 
   815 
   816 *** Syntax ***
   817 
   818 * TYPE('a) syntax for type reflection terms;
   819 
   820 * no longer handles consts with name "" -- declare as 'syntax' instead;
   821 
   822 * pretty printer: changed order of mixfix annotation preference (again!);
   823 
   824 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   825 
   826 
   827 *** HOL ***
   828 
   829 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   830   with `addloop' of the simplifier to faciliate case splitting in premises.
   831 
   832 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   833 
   834 * HOL/Auth: new protocol proofs including some for the Internet
   835   protocol TLS;
   836 
   837 * HOL/Map: new theory of `maps' a la VDM;
   838 
   839 * HOL/simplifier: simplification procedures nat_cancel_sums for
   840 cancelling out common nat summands from =, <, <= (in)equalities, or
   841 differences; simplification procedures nat_cancel_factor for
   842 cancelling common factor from =, <, <= (in)equalities over natural
   843 sums; nat_cancel contains both kinds of procedures, it is installed by
   844 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   845 
   846 * HOL/simplifier: terms of the form
   847   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   848   are rewritten to
   849   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   850   and those of the form
   851   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   852   are rewritten to
   853   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   854 
   855 * HOL/datatype
   856   Each datatype `t' now comes with a theorem `split_t_case' of the form
   857 
   858   P(t_case f1 ... fn x) =
   859      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   860         ...
   861        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   862      )
   863 
   864   and a theorem `split_t_case_asm' of the form
   865 
   866   P(t_case f1 ... fn x) =
   867     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   868         ...
   869        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   870      )
   871   which can be added to a simpset via `addsplits'. The existing theorems
   872   expand_list_case and expand_option_case have been renamed to
   873   split_list_case and split_option_case.
   874 
   875 * HOL/Arithmetic:
   876   - `pred n' is automatically converted to `n-1'.
   877     Users are strongly encouraged not to use `pred' any longer,
   878     because it will disappear altogether at some point.
   879   - Users are strongly encouraged to write "0 < n" rather than
   880     "n ~= 0". Theorems and proof tools have been modified towards this
   881     `standard'.
   882 
   883 * HOL/Lists:
   884   the function "set_of_list" has been renamed "set" (and its theorems too);
   885   the function "nth" now takes its arguments in the reverse order and
   886   has acquired the infix notation "!" as in "xs!n".
   887 
   888 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   889 
   890 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   891   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   892 
   893 * HOL/record: extensible records with schematic structural subtyping
   894 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   895 still lacks various theorems and concrete record syntax;
   896 
   897 
   898 *** HOLCF ***
   899 
   900 * removed "axioms" and "generated by" sections;
   901 
   902 * replaced "ops" section by extended "consts" section, which is capable of
   903   handling the continuous function space "->" directly;
   904 
   905 * domain package:
   906   . proves theorems immediately and stores them in the theory,
   907   . creates hierachical name space,
   908   . now uses normal mixfix annotations (instead of cinfix...),
   909   . minor changes to some names and values (for consistency),
   910   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   911   . separator between mutual domain defs: changed "," to "and",
   912   . improved handling of sort constraints;  now they have to
   913     appear on the left-hand side of the equations only;
   914 
   915 * fixed LAM <x,y,zs>.b syntax;
   916 
   917 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   918 adm (%x. P (t x)), where P is chainfinite and t continuous;
   919 
   920 
   921 *** FOL and ZF ***
   922 
   923 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   924   with `addloop' of the simplifier to faciliate case splitting in premises.
   925 
   926 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   927 in HOL, they strip ALL and --> from proved theorems;
   928 
   929 
   930 
   931 New in Isabelle94-8 (May 1997)
   932 ------------------------------
   933 
   934 *** General Changes ***
   935 
   936 * new utilities to build / run / maintain Isabelle etc. (in parts
   937 still somewhat experimental); old Makefiles etc. still functional;
   938 
   939 * new 'Isabelle System Manual';
   940 
   941 * INSTALL text, together with ./configure and ./build scripts;
   942 
   943 * reimplemented type inference for greater efficiency, better error
   944 messages and clean internal interface;
   945 
   946 * prlim command for dealing with lots of subgoals (an easier way of
   947 setting goals_limit);
   948 
   949 
   950 *** Syntax ***
   951 
   952 * supports alternative (named) syntax tables (parser and pretty
   953 printer); internal interface is provided by add_modesyntax(_i);
   954 
   955 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   956 be used in conjunction with the Isabelle symbol font; uses the
   957 "symbols" syntax table;
   958 
   959 * added token_translation interface (may translate name tokens in
   960 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   961 the current print_mode); IMPORTANT: user print translation functions
   962 are responsible for marking newly introduced bounds
   963 (Syntax.mark_boundT);
   964 
   965 * token translations for modes "xterm" and "xterm_color" that display
   966 names in bold, underline etc. or colors (which requires a color
   967 version of xterm);
   968 
   969 * infixes may now be declared with names independent of their syntax;
   970 
   971 * added typed_print_translation (like print_translation, but may
   972 access type of constant);
   973 
   974 
   975 *** Classical Reasoner ***
   976 
   977 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   978 some limitations.  Blast_tac...
   979   + ignores addss, addbefore, addafter; this restriction is intrinsic
   980   + ignores elimination rules that don't have the correct format
   981         (the conclusion MUST be a formula variable)
   982   + ignores types, which can make HOL proofs fail
   983   + rules must not require higher-order unification, e.g. apply_type in ZF
   984     [message "Function Var's argument not a bound variable" relates to this]
   985   + its proof strategy is more general but can actually be slower
   986 
   987 * substitution with equality assumptions no longer permutes other
   988 assumptions;
   989 
   990 * minor changes in semantics of addafter (now called addaltern); renamed
   991 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   992 (and access functions for it);
   993 
   994 * improved combination of classical reasoner and simplifier:
   995   + functions for handling clasimpsets
   996   + improvement of addss: now the simplifier is called _after_ the
   997     safe steps.
   998   + safe variant of addss called addSss: uses safe simplifications
   999     _during_ the safe steps. It is more complete as it allows multiple
  1000     instantiations of unknowns (e.g. with slow_tac).
  1001 
  1002 *** Simplifier ***
  1003 
  1004 * added interface for simplification procedures (functions that
  1005 produce *proven* rewrite rules on the fly, depending on current
  1006 redex);
  1007 
  1008 * ordering on terms as parameter (used for ordered rewriting);
  1009 
  1010 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1011 
  1012 * the solver is now split into a safe and an unsafe part.
  1013 This should be invisible for the normal user, except that the
  1014 functions setsolver and addsolver have been renamed to setSolver and
  1015 addSolver; added safe_asm_full_simp_tac;
  1016 
  1017 
  1018 *** HOL ***
  1019 
  1020 * a generic induction tactic `induct_tac' which works for all datatypes and
  1021 also for type `nat';
  1022 
  1023 * a generic case distinction tactic `exhaust_tac' which works for all
  1024 datatypes and also for type `nat';
  1025 
  1026 * each datatype comes with a function `size';
  1027 
  1028 * patterns in case expressions allow tuple patterns as arguments to
  1029 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1030 
  1031 * primrec now also works with type nat;
  1032 
  1033 * recdef: a new declaration form, allows general recursive functions to be
  1034 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1035 
  1036 * the constant for negation has been renamed from "not" to "Not" to
  1037 harmonize with FOL, ZF, LK, etc.;
  1038 
  1039 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1040 infinite lists;
  1041 
  1042 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1043 
  1044 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1045 problems in commutative rings, using axiomatic type classes for + and *;
  1046 
  1047 * more examples in HOL/MiniML and HOL/Auth;
  1048 
  1049 * more default rewrite rules for quantifiers, union/intersection;
  1050 
  1051 * a new constant `arbitrary == @x.False';
  1052 
  1053 * HOLCF/IOA replaces old HOL/IOA;
  1054 
  1055 * HOLCF changes: derived all rules and arities
  1056   + axiomatic type classes instead of classes
  1057   + typedef instead of faking type definitions
  1058   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1059   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1060   + eliminated the types void, one, tr
  1061   + use unit lift and bool lift (with translations) instead of one and tr
  1062   + eliminated blift from Lift3.thy (use Def instead of blift)
  1063   all eliminated rules are derived as theorems --> no visible changes ;
  1064 
  1065 
  1066 *** ZF ***
  1067 
  1068 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1069 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1070 as ZF_cs addSIs [equalityI];
  1071 
  1072 
  1073 
  1074 New in Isabelle94-7 (November 96)
  1075 ---------------------------------
  1076 
  1077 * allowing negative levels (as offsets) in prlev and choplev;
  1078 
  1079 * super-linear speedup for large simplifications;
  1080 
  1081 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1082 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1083 FAIL); can suppress it using the command Delsimps (ex_simps @
  1084 all_simps); De Morgan laws are also now included, by default;
  1085 
  1086 * improved printing of ==>  :  ~:
  1087 
  1088 * new object-logic "Sequents" adds linear logic, while replacing LK
  1089 and Modal (thanks to Sara Kalvala);
  1090 
  1091 * HOL/Auth: correctness proofs for authentication protocols;
  1092 
  1093 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1094 examples on HOL/Auth);
  1095 
  1096 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1097 the rewriter and classical reasoner simultaneously;
  1098 
  1099 * function uresult no longer returns theorems in "standard" format;
  1100 regain previous version by: val uresult = standard o uresult;
  1101 
  1102 
  1103 
  1104 New in Isabelle94-6
  1105 -------------------
  1106 
  1107 * oracles -- these establish an interface between Isabelle and trusted
  1108 external reasoners, which may deliver results as theorems;
  1109 
  1110 * proof objects (in particular record all uses of oracles);
  1111 
  1112 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1113 
  1114 * "constdefs" section in theory files;
  1115 
  1116 * "primrec" section (HOL) no longer requires names;
  1117 
  1118 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1119 
  1120 
  1121 
  1122 New in Isabelle94-5
  1123 -------------------
  1124 
  1125 * reduced space requirements;
  1126 
  1127 * automatic HTML generation from theories;
  1128 
  1129 * theory files no longer require "..." (quotes) around most types;
  1130 
  1131 * new examples, including two proofs of the Church-Rosser theorem;
  1132 
  1133 * non-curried (1994) version of HOL is no longer distributed;
  1134 
  1135 
  1136 
  1137 New in Isabelle94-4
  1138 -------------------
  1139 
  1140 * greatly reduced space requirements;
  1141 
  1142 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1143 
  1144 * searchable theorem database (see the section "Retrieving theorems" on
  1145 page 8 of the Reference Manual);
  1146 
  1147 * new examples, including Grabczewski's monumental case study of the
  1148 Axiom of Choice;
  1149 
  1150 * The previous version of HOL renamed to Old_HOL;
  1151 
  1152 * The new version of HOL (previously called CHOL) uses a curried syntax
  1153 for functions.  Application looks like f a b instead of f(a,b);
  1154 
  1155 * Mutually recursive inductive definitions finally work in HOL;
  1156 
  1157 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1158 translates to the operator "split";
  1159 
  1160 
  1161 
  1162 New in Isabelle94-3
  1163 -------------------
  1164 
  1165 * new infix operator, addss, allowing the classical reasoner to
  1166 perform simplification at each step of its search.  Example:
  1167         fast_tac (cs addss ss)
  1168 
  1169 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1170 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1171 look like (a,b) instead of <a,b>;
  1172 
  1173 * PLEASE NOTE: CHOL will eventually replace HOL!
  1174 
  1175 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1176 It translates to the operator "split".  A new theory of integers is available;
  1177 
  1178 * In ZF, integer numerals now denote two's-complement binary integers.
  1179 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1180 
  1181 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1182 of the Axiom of Choice;
  1183 
  1184 
  1185 
  1186 New in Isabelle94-2
  1187 -------------------
  1188 
  1189 * Significantly faster resolution;
  1190 
  1191 * the different sections in a .thy file can now be mixed and repeated
  1192 freely;
  1193 
  1194 * Database of theorems for FOL, HOL and ZF.  New
  1195 commands including qed, qed_goal and bind_thm store theorems in the database.
  1196 
  1197 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1198 a given theory (thms_of), or find out what theory a theorem was proved in
  1199 (theory_of_thm);
  1200 
  1201 * Bugs fixed in the inductive definition and datatype packages;
  1202 
  1203 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1204 and HOL_dup_cs obsolete;
  1205 
  1206 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1207 have been removed;
  1208 
  1209 * Simpler definition of function space in ZF;
  1210 
  1211 * new results about cardinal and ordinal arithmetic in ZF;
  1212 
  1213 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1214 types;
  1215 
  1216 
  1217 $Id$