NEWS
author wenzelm
Fri Nov 12 10:57:28 1999 +0100 (1999-11-12)
changeset 8015 4a687092b201
parent 8014 fdf1281a3d0c
child 8184 6b7ef9fc39da
permissions -rw-r--r--
tuned;
     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 *** HOL ***
    14 
    15 * Algebra: new theory of rings and univariate polynomials, by Clemens Ballarin
    16 
    17 
    18 
    19 New in Isabelle99 (October 1999)
    20 --------------------------------
    21 
    22 *** Overview of INCOMPATIBILITIES (see below for more details) ***
    23 
    24 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
    25 are no longer simplified.  (This allows the simplifier to unfold recursive
    26 functional programs.)  To restore the old behaviour, declare
    27 
    28     Delcongs [if_weak_cong];
    29 
    30 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    31 complement;
    32 
    33 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    34 
    35 * HOL/datatype: mutual_induct_tac no longer exists --
    36   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
    37 
    38 * HOL/typedef: fixed type inference for representing set; type
    39 arguments now have to occur explicitly on the rhs as type constraints;
    40 
    41 * ZF: The con_defs part of an inductive definition may no longer refer
    42 to constants declared in the same theory;
    43 
    44 * HOL, ZF: the function mk_cases, generated by the inductive
    45 definition package, has lost an argument.  To simplify its result, it
    46 uses the default simpset instead of a supplied list of theorems.
    47 
    48 * HOL/List: the constructors of type list are now Nil and Cons;
    49 
    50 * Simplifier: the type of the infix ML functions
    51 	setSSolver addSSolver setSolver addSolver
    52 is now  simpset * solver -> simpset  where `solver' is a new abstract type
    53 for packaging solvers. A solver is created via
    54 	mk_solver: string -> (thm list -> int -> tactic) -> solver
    55 where the string argument is only a comment.
    56 
    57 
    58 *** Proof tools ***
    59 
    60 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
    61 decision procedure for linear arithmetic. Currently it is used for
    62 types `nat', `int', and `real' in HOL (see below); it can, should and
    63 will be instantiated for other types and logics as well.
    64 
    65 * The simplifier now accepts rewrite rules with flexible heads, eg
    66      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
    67   They are applied like any rule with a non-pattern lhs, i.e. by first-order
    68   matching.
    69 
    70 
    71 *** General ***
    72 
    73 * New Isabelle/Isar subsystem provides an alternative to traditional
    74 tactical theorem proving; together with the ProofGeneral/isar user
    75 interface it offers an interactive environment for developing human
    76 readable proof documents (Isar == Intelligible semi-automated
    77 reasoning); for further information see isatool doc isar-ref,
    78 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
    79 
    80 * improved presentation of theories: better HTML markup (including
    81 colors), graph views in several sizes; isatool usedir now provides a
    82 proper interface for user theories (via -P option); actual document
    83 preparation based on (PDF)LaTeX is available as well (for new-style
    84 theories only); see isatool doc system for more information;
    85 
    86 * native support for Proof General, both for classic Isabelle and
    87 Isabelle/Isar;
    88 
    89 * ML function thm_deps visualizes dependencies of theorems and lemmas,
    90 using the graph browser tool;
    91 
    92 * Isabelle manuals now also available as PDF;
    93 
    94 * theory loader rewritten from scratch (may not be fully
    95 bug-compatible); old loadpath variable has been replaced by show_path,
    96 add_path, del_path, reset_path functions; new operations such as
    97 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
    98 isatool doc ref);
    99 
   100 * improved isatool install: option -k creates KDE application icon,
   101 option -p DIR installs standalone binaries;
   102 
   103 * added ML_PLATFORM setting (useful for cross-platform installations);
   104 more robust handling of platform specific ML images for SML/NJ;
   105 
   106 * the settings environment is now statically scoped, i.e. it is never
   107 created again in sub-processes invoked from isabelle, isatool, or
   108 Isabelle;
   109 
   110 * path element specification '~~' refers to '$ISABELLE_HOME';
   111 
   112 * in locales, the "assumes" and "defines" parts may be omitted if
   113 empty;
   114 
   115 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   116 long arrows);
   117 
   118 * new print_mode "HTML";
   119 
   120 * new flag show_tags controls display of tags of theorems (which are
   121 basically just comments that may be attached by some tools);
   122 
   123 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   124 mode and goal output format:
   125 
   126 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   127 244c244
   128 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   129 ---
   130 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   131 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   132 181c181
   133 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   134 ---
   135 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   136 
   137 * function bind_thms stores lists of theorems (cf. bind_thm);
   138 
   139 * new shorthand tactics ftac, eatac, datac, fatac;
   140 
   141 * qed (and friends) now accept "" as result name; in that case the
   142 theorem is not stored, but proper checks and presentation of the
   143 result still apply;
   144 
   145 * theorem database now also indexes constants "Trueprop", "all",
   146 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   147 
   148 
   149 *** HOL ***
   150 
   151 ** HOL arithmetic **
   152 
   153 * There are now decision procedures for linear arithmetic over nat and
   154 int:
   155 
   156 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   157 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   158 are treated as atomic; subformulae not involving type `nat' or `int'
   159 are ignored; quantified subformulae are ignored unless they are
   160 positive universal or negative existential. The tactic has to be
   161 invoked by hand and can be a little bit slow. In particular, the
   162 running time is exponential in the number of occurrences of `min' and
   163 `max', and `-' on `nat'.
   164 
   165 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   166 (negated) (in)equalities among the premises and the conclusion into
   167 account (i.e. no compound formulae) and does not know about `min' and
   168 `max', and `-' on `nat'. It is fast and is used automatically by the
   169 simplifier.
   170 
   171 NB: At the moment, these decision procedures do not cope with mixed
   172 nat/int formulae where the two parts interact, such as `m < n ==>
   173 int(m) < int(n)'.
   174 
   175 * HOL/Numeral provides a generic theory of numerals (encoded
   176 efficiently as bit strings); setup for types nat/int/real is in place;
   177 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   178 int, existing theories and proof scripts may require a few additional
   179 type constraints;
   180 
   181 * integer division and remainder can now be performed on constant
   182 arguments;
   183 
   184 * many properties of integer multiplication, division and remainder
   185 are now available;
   186 
   187 * An interface to the Stanford Validity Checker (SVC) is available through the
   188 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   189 are proved automatically.  SVC must be installed separately, and its results
   190 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   191 invocation of the underlying oracle).  For SVC see
   192   http://verify.stanford.edu/SVC
   193 
   194 * IsaMakefile: the HOL-Real target now builds an actual image;
   195 
   196 
   197 ** HOL misc **
   198 
   199 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   200 (in Isabelle/Isar) -- by Gertrud Bauer;
   201 
   202 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   203 analysis for assembly languages with subtypes;
   204 
   205 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   206 -- avoids syntactic ambiguities and treats state, transition, and
   207 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   208 changed syntax and (many) tactics;
   209 
   210 * HOL/inductive: Now also handles more general introduction rules such
   211   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   212   theorems are now maintained within the theory (maintained via the
   213   "mono" attribute);
   214 
   215 * HOL/datatype: Now also handles arbitrarily branching datatypes
   216   (using function types) such as
   217 
   218   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   219 
   220 * HOL/record: record_simproc (part of the default simpset) takes care
   221 of selectors applied to updated records; record_split_tac is no longer
   222 part of the default claset; update_defs may now be removed from the
   223 simpset in many cases; COMPATIBILITY: old behavior achieved by
   224 
   225   claset_ref () := claset() addSWrapper record_split_wrapper;
   226   Delsimprocs [record_simproc]
   227 
   228 * HOL/typedef: fixed type inference for representing set; type
   229 arguments now have to occur explicitly on the rhs as type constraints;
   230 
   231 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   232 names rather than an ML expression;
   233 
   234 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   235 supplied later.  Program schemes can be defined, such as
   236     "While B C s = (if B s then While B C (C s) else s)"
   237 where the well-founded relation can be chosen after B and C have been given.
   238 
   239 * HOL/List: the constructors of type list are now Nil and Cons;
   240 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   241 course, ML tools referring to List.list.op # etc. have to be adapted;
   242 
   243 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   244 disabled by default; run isabelle with option -m HOL to get back to
   245 the original Gordon/HOL-style output;
   246 
   247 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   248 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   249 
   250 * HOL basic syntax simplified (more orthogonal): all variants of
   251 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   252 Eps operator is provided as well: "SOME x. P[x]";
   253 
   254 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   255 
   256 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   257 thus available for user theories;
   258 
   259 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   260 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   261 time;
   262 
   263 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   264 several times and then mp;
   265 
   266 
   267 *** LK ***
   268 
   269 * the notation <<...>> is now available as a notation for sequences of
   270 formulas;
   271 
   272 * the simplifier is now installed
   273 
   274 * the axiom system has been generalized (thanks to Soren Heilmann) 
   275 
   276 * the classical reasoner now has a default rule database
   277 
   278 
   279 *** ZF ***
   280 
   281 * new primrec section allows primitive recursive functions to be given
   282 directly (as in HOL) over datatypes and the natural numbers;
   283 
   284 * new tactics induct_tac and exhaust_tac for induction (or case
   285 analysis) over datatypes and the natural numbers;
   286 
   287 * the datatype declaration of type T now defines the recursor T_rec;
   288 
   289 * simplification automatically does freeness reasoning for datatype
   290 constructors;
   291 
   292 * automatic type-inference, with AddTCs command to insert new
   293 type-checking rules;
   294 
   295 * datatype introduction rules are now added as Safe Introduction rules
   296 to the claset;
   297 
   298 * the syntax "if P then x else y" is now available in addition to
   299 if(P,x,y);
   300 
   301 
   302 *** Internal programming interfaces ***
   303 
   304 * tuned simplifier trace output; new flag debug_simp;
   305 
   306 * structures Vartab / Termtab (instances of TableFun) offer efficient
   307 tables indexed by indexname_ord / term_ord (compatible with aconv);
   308 
   309 * AxClass.axclass_tac lost the theory argument;
   310 
   311 * tuned current_goals_markers semantics: begin / end goal avoids
   312 printing empty lines;
   313 
   314 * removed prs and prs_fn hook, which was broken because it did not
   315 include \n in its semantics, forcing writeln to add one
   316 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   317 string -> unit if you really want to output text without newline;
   318 
   319 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   320 plain output, interface builders may have to enable 'isabelle_font'
   321 mode to get Isabelle font glyphs as before;
   322 
   323 * refined token_translation interface; INCOMPATIBILITY: output length
   324 now of type real instead of int;
   325 
   326 * theory loader actions may be traced via new ThyInfo.add_hook
   327 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   328 your own database of information attached to *whole* theories -- as
   329 opposed to intra-theory data slots offered via TheoryDataFun;
   330 
   331 * proper handling of dangling sort hypotheses (at last!);
   332 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   333 extra sort hypotheses that can be witnessed from the type signature;
   334 the force_strip_shyps flag is gone, any remaining shyps are simply
   335 left in the theorem (with a warning issued by strip_shyps_warning);
   336 
   337 
   338 
   339 New in Isabelle98-1 (October 1998)
   340 ----------------------------------
   341 
   342 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   343 
   344 * several changes of automated proof tools;
   345 
   346 * HOL: major changes to the inductive and datatype packages, including
   347 some minor incompatibilities of theory syntax;
   348 
   349 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   350 called `inj_on';
   351 
   352 * HOL: removed duplicate thms in Arith:
   353   less_imp_add_less  should be replaced by  trans_less_add1
   354   le_imp_add_le      should be replaced by  trans_le_add1
   355 
   356 * HOL: unary minus is now overloaded (new type constraints may be
   357 required);
   358 
   359 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   360 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   361 now taken as an integer constant.
   362 
   363 * Pure: ML function 'theory_of' renamed to 'theory';
   364 
   365 
   366 *** Proof tools ***
   367 
   368 * Simplifier:
   369   1. Asm_full_simp_tac is now more aggressive.
   370      1. It will sometimes reorient premises if that increases their power to
   371         simplify.
   372      2. It does no longer proceed strictly from left to right but may also
   373         rotate premises to achieve further simplification.
   374      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   375      old Asm_full_simp_tac in that it does not rotate premises.
   376   2. The simplifier now knows a little bit about nat-arithmetic.
   377 
   378 * Classical reasoner: wrapper mechanism for the classical reasoner now
   379 allows for selected deletion of wrappers, by introduction of names for
   380 wrapper functionals.  This implies that addbefore, addSbefore,
   381 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   382 and that adding two tactics with the same name overwrites the first
   383 one (emitting a warning).
   384   type wrapper = (int -> tactic) -> (int -> tactic)
   385   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   386   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   387   delWrapper, delSWrapper: claset *  string            -> claset
   388   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   389 
   390 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   391 semantics; addbefore now affects only the unsafe part of step_tac
   392 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   393 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   394 by Force_tac;
   395 
   396 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   397 compWrapper; added safe wrapper (and access functions for it);
   398 
   399 * HOL/split_all_tac is now much faster and fails if there is nothing
   400 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   401 and the names of the automatically generated variables have changed.
   402 split_all_tac has moved within claset() from unsafe wrappers to safe
   403 wrappers, which means that !!-bound variables are split much more
   404 aggressively, and safe_tac and clarify_tac now split such variables.
   405 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   406 Note: the same holds for record_split_tac, which does the job of
   407 split_all_tac for record fields.
   408 
   409 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   410 permanently to the default simpset using Addsplits just like
   411 Addsimps. They can be removed via Delsplits just like
   412 Delsimps. Lower-case versions are also available.
   413 
   414 * HOL/Simplifier: The rule split_if is now part of the default
   415 simpset. This means that the simplifier will eliminate all occurrences
   416 of if-then-else in the conclusion of a goal. To prevent this, you can
   417 either remove split_if completely from the default simpset by
   418 `Delsplits [split_if]' or remove it in a specific call of the
   419 simplifier using `... delsplits [split_if]'.  You can also add/delete
   420 other case splitting rules to/from the default simpset: every datatype
   421 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   422 t is the name of the datatype).
   423 
   424 * Classical reasoner / Simplifier combination: new force_tac (and
   425 derivatives Force_tac, force) combines rewriting and classical
   426 reasoning (and whatever other tools) similarly to auto_tac, but is
   427 aimed to solve the given subgoal completely.
   428 
   429 
   430 *** General ***
   431 
   432 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   433 and `goalw': the theory is no longer needed as an explicit argument -
   434 the current theory context is used; assumptions are no longer returned
   435 at the ML-level unless one of them starts with ==> or !!; it is
   436 recommended to convert to these new commands using isatool fixgoal
   437 (backup your sources first!);
   438 
   439 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   440 the current theory context, and 'theory' to lookup stored theories;
   441 
   442 * new theory section 'locale' for declaring constants, assumptions and
   443 definitions that have local scope;
   444 
   445 * new theory section 'nonterminals' for purely syntactic types;
   446 
   447 * new theory section 'setup' for generic ML setup functions
   448 (e.g. package initialization);
   449 
   450 * the distribution now includes Isabelle icons: see
   451 lib/logo/isabelle-{small,tiny}.xpm;
   452 
   453 * isatool install - install binaries with absolute references to
   454 ISABELLE_HOME/bin;
   455 
   456 * isatool logo -- create instances of the Isabelle logo (as EPS);
   457 
   458 * print mode 'emacs' reserved for Isamode;
   459 
   460 * support multiple print (ast) translations per constant name;
   461 
   462 * theorems involving oracles are now printed with a suffixed [!];
   463 
   464 
   465 *** HOL ***
   466 
   467 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   468 
   469 * HOL/inductive package reorganized and improved: now supports mutual
   470 definitions such as
   471 
   472   inductive EVEN ODD
   473     intrs
   474       null "0 : EVEN"
   475       oddI "n : EVEN ==> Suc n : ODD"
   476       evenI "n : ODD ==> Suc n : EVEN"
   477 
   478 new theorem list "elims" contains an elimination rule for each of the
   479 recursive sets; inductive definitions now handle disjunctive premises
   480 correctly (also ZF);
   481 
   482 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   483 "mutual_induct" no longer exists - the induction rule is always
   484 contained in "induct";
   485 
   486 
   487 * HOL/datatype package re-implemented and greatly improved: now
   488 supports mutually recursive datatypes such as
   489 
   490   datatype
   491     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   492             | SUM ('a aexp) ('a aexp)
   493             | DIFF ('a aexp) ('a aexp)
   494             | NUM 'a
   495   and
   496     'a bexp = LESS ('a aexp) ('a aexp)
   497             | AND ('a bexp) ('a bexp)
   498             | OR ('a bexp) ('a bexp)
   499 
   500 as well as indirectly recursive datatypes such as
   501 
   502   datatype
   503     ('a, 'b) term = Var 'a
   504                   | App 'b ((('a, 'b) term) list)
   505 
   506 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   507 induction on mutually / indirectly recursive datatypes.
   508 
   509 Primrec equations are now stored in theory and can be accessed via
   510 <function_name>.simps.
   511 
   512 INCOMPATIBILITIES:
   513 
   514   - Theories using datatypes must now have theory Datatype as an
   515     ancestor.
   516   - The specific <typename>.induct_tac no longer exists - use the
   517     generic induct_tac instead.
   518   - natE has been renamed to nat.exhaust - use exhaust_tac
   519     instead of res_inst_tac ... natE. Note that the variable
   520     names in nat.exhaust differ from the names in natE, this
   521     may cause some "fragile" proofs to fail.
   522   - The theorems split_<typename>_case and split_<typename>_case_asm
   523     have been renamed to <typename>.split and <typename>.split_asm.
   524   - Since default sorts of type variables are now handled correctly,
   525     some datatype definitions may have to be annotated with explicit
   526     sort constraints.
   527   - Primrec definitions no longer require function name and type
   528     of recursive argument.
   529 
   530 Consider using isatool fixdatatype to adapt your theories and proof
   531 scripts to the new package (backup your sources first!).
   532 
   533 
   534 * HOL/record package: considerably improved implementation; now
   535 includes concrete syntax for record types, terms, updates; theorems
   536 for surjective pairing and splitting !!-bound record variables; proof
   537 support is as follows:
   538 
   539   1) standard conversions (selectors or updates applied to record
   540 constructor terms) are part of the standard simpset;
   541 
   542   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   543 made part of standard simpset and claset via addIffs;
   544 
   545   3) a tactic for record field splitting (record_split_tac) is part of
   546 the standard claset (addSWrapper);
   547 
   548 To get a better idea about these rules you may retrieve them via
   549 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   550 the name of your record type.
   551 
   552 The split tactic 3) conceptually simplifies by the following rule:
   553 
   554   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   555 
   556 Thus any record variable that is bound by meta-all will automatically
   557 blow up into some record constructor term, consequently the
   558 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   559 solve record problems automatically.
   560 
   561 
   562 * reorganized the main HOL image: HOL/Integ and String loaded by
   563 default; theory Main includes everything;
   564 
   565 * automatic simplification of integer sums and comparisons, using cancellation;
   566 
   567 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   568 
   569 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   570 
   571 * many new identities for unions, intersections, set difference, etc.;
   572 
   573 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   574 called split_if, split_split, split_sum_case and split_nat_case (to go
   575 with add/delsplits);
   576 
   577 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   578 (?x::unit) = (); this is made part of the default simpset, which COULD
   579 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   580 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   581 unit_abs_eta_conv is added in order to counter the effect of
   582 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   583 %u.f();
   584 
   585 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   586 makes more sense);
   587 
   588 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   589   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   590   disjointness reasoning but breaking a few old proofs.
   591 
   592 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   593 to 'converse' from 'inverse' (for compatibility with ZF and some
   594 literature);
   595 
   596 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   597 the well-founded relation;
   598 
   599 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   600     Compl A.  The "Compl" syntax remains available as input syntax for this
   601     release ONLY.
   602 
   603 * HOL/Update: new theory of function updates:
   604     f(a:=b) == %x. if x=a then b else f x
   605 may also be iterated as in f(a:=b,c:=d,...);
   606 
   607 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   608 
   609 * HOL/List:
   610   - new function list_update written xs[i:=v] that updates the i-th
   611     list position. May also be iterated as in xs[i:=a,j:=b,...].
   612   - new function `upt' written [i..j(] which generates the list
   613     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   614     bound write [i..j], which is a shorthand for [i..j+1(].
   615   - new lexicographic orderings and corresponding wellfoundedness theorems.
   616 
   617 * HOL/Arith:
   618   - removed 'pred' (predecessor) function;
   619   - generalized some theorems about n-1;
   620   - many new laws about "div" and "mod";
   621   - new laws about greatest common divisors (see theory ex/Primes);
   622 
   623 * HOL/Relation: renamed the relational operator r^-1 "converse"
   624 instead of "inverse";
   625 
   626 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   627   of the multiset ordering;
   628 
   629 * directory HOL/Real: a construction of the reals using Dedekind cuts
   630   (not included by default);
   631 
   632 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   633 
   634 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   635   programs, i.e. different program variables may have different types.
   636 
   637 * calling (stac rew i) now fails if "rew" has no effect on the goal
   638   [previously, this check worked only if the rewrite rule was unconditional]
   639   Now rew can involve either definitions or equalities (either == or =).
   640 
   641 
   642 *** ZF ***
   643 
   644 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   645   only the theorems proved on ZF.ML;
   646 
   647 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   648   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   649   disjointness reasoning but breaking a few old proofs.
   650 
   651 * ZF/Update: new theory of function updates
   652     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   653   may also be iterated as in f(a:=b,c:=d,...);
   654 
   655 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   656 
   657 * calling (stac rew i) now fails if "rew" has no effect on the goal
   658   [previously, this check worked only if the rewrite rule was unconditional]
   659   Now rew can involve either definitions or equalities (either == or =).
   660 
   661 * case_tac provided for compatibility with HOL
   662     (like the old excluded_middle_tac, but with subgoals swapped)
   663 
   664 
   665 *** Internal programming interfaces ***
   666 
   667 * Pure: several new basic modules made available for general use, see
   668 also src/Pure/README;
   669 
   670 * improved the theory data mechanism to support encapsulation (data
   671 kind name replaced by private Object.kind, acting as authorization
   672 key); new type-safe user interface via functor TheoryDataFun; generic
   673 print_data function becomes basically useless;
   674 
   675 * removed global_names compatibility flag -- all theory declarations
   676 are qualified by default;
   677 
   678 * module Pure/Syntax now offers quote / antiquote translation
   679 functions (useful for Hoare logic etc. with implicit dependencies);
   680 see HOL/ex/Antiquote for an example use;
   681 
   682 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   683 cterm -> thm;
   684 
   685 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   686 subgoal;
   687 
   688 * Display.print_goals function moved to Locale.print_goals;
   689 
   690 * standard print function for goals supports current_goals_markers
   691 variable for marking begin of proof, end of proof, start of goal; the
   692 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   693 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   694 for example;
   695 
   696 
   697 
   698 New in Isabelle98 (January 1998)
   699 --------------------------------
   700 
   701 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   702 
   703 * changed lexical syntax of terms / types: dots made part of long
   704 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   705 
   706 * simpset (and claset) reference variable replaced by functions
   707 simpset / simpset_ref;
   708 
   709 * no longer supports theory aliases (via merge) and non-trivial
   710 implicit merge of thms' signatures;
   711 
   712 * most internal names of constants changed due to qualified names;
   713 
   714 * changed Pure/Sequence interface (see Pure/seq.ML);
   715 
   716 
   717 *** General Changes ***
   718 
   719 * hierachically structured name spaces (for consts, types, axms, thms
   720 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   721 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   722 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   723 long_names for fully qualified output names; NOTE: ML programs
   724 (special tactics, packages etc.) referring to internal names may have
   725 to be adapted to cope with fully qualified names; in case of severe
   726 backward campatibility problems try setting 'global_names' at compile
   727 time to have enrything declared within a flat name space; one may also
   728 fine tune name declarations in theories via the 'global' and 'local'
   729 section;
   730 
   731 * reimplemented the implicit simpset and claset using the new anytype
   732 data filed in signatures; references simpset:simpset ref etc. are
   733 replaced by functions simpset:unit->simpset and
   734 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   735 to patch your ML files accordingly;
   736 
   737 * HTML output now includes theory graph data for display with Java
   738 applet or isatool browser; data generated automatically via isatool
   739 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   740 
   741 * defs may now be conditional; improved rewrite_goals_tac to handle
   742 conditional equations;
   743 
   744 * defs now admits additional type arguments, using TYPE('a) syntax;
   745 
   746 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   747 creates a new theory node; implicit merge of thms' signatures is
   748 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   749 transfer:theory->thm->thm in (rare) cases;
   750 
   751 * improved handling of draft signatures / theories; draft thms (and
   752 ctyps, cterms) are automatically promoted to real ones;
   753 
   754 * slightly changed interfaces for oracles: admit many per theory, named
   755 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   756 
   757 * print_goals: optional output of const types (set show_consts and
   758 show_types);
   759 
   760 * improved output of warnings (###) and errors (***);
   761 
   762 * subgoal_tac displays a warning if the new subgoal has type variables;
   763 
   764 * removed old README and Makefiles;
   765 
   766 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   767 
   768 * removed obsolete init_pps and init_database;
   769 
   770 * deleted the obsolete tactical STATE, which was declared by
   771     fun STATE tacfun st = tacfun st st;
   772 
   773 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   774 (which abbreviates $HOME);
   775 
   776 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   777 use isatool fixseq to adapt your ML programs (this works for fully
   778 qualified references to the Sequence structure only!);
   779 
   780 * use_thy no longer requires writable current directory; it always
   781 reloads .ML *and* .thy file, if either one is out of date;
   782 
   783 
   784 *** Classical Reasoner ***
   785 
   786 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   787 tactics that use classical reasoning to simplify a subgoal without
   788 splitting it into several subgoals;
   789 
   790 * Safe_tac: like safe_tac but uses the default claset;
   791 
   792 
   793 *** Simplifier ***
   794 
   795 * added simplification meta rules:
   796     (asm_)(full_)simplify: simpset -> thm -> thm;
   797 
   798 * simplifier.ML no longer part of Pure -- has to be loaded by object
   799 logics (again);
   800 
   801 * added prems argument to simplification procedures;
   802 
   803 * HOL, FOL, ZF: added infix function `addsplits':
   804   instead of `<simpset> setloop (split_tac <thms>)'
   805   you can simply write `<simpset> addsplits <thms>'
   806 
   807 
   808 *** Syntax ***
   809 
   810 * TYPE('a) syntax for type reflection terms;
   811 
   812 * no longer handles consts with name "" -- declare as 'syntax' instead;
   813 
   814 * pretty printer: changed order of mixfix annotation preference (again!);
   815 
   816 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   817 
   818 
   819 *** HOL ***
   820 
   821 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   822   with `addloop' of the simplifier to faciliate case splitting in premises.
   823 
   824 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   825 
   826 * HOL/Auth: new protocol proofs including some for the Internet
   827   protocol TLS;
   828 
   829 * HOL/Map: new theory of `maps' a la VDM;
   830 
   831 * HOL/simplifier: simplification procedures nat_cancel_sums for
   832 cancelling out common nat summands from =, <, <= (in)equalities, or
   833 differences; simplification procedures nat_cancel_factor for
   834 cancelling common factor from =, <, <= (in)equalities over natural
   835 sums; nat_cancel contains both kinds of procedures, it is installed by
   836 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   837 
   838 * HOL/simplifier: terms of the form
   839   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   840   are rewritten to
   841   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   842   and those of the form
   843   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   844   are rewritten to
   845   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   846 
   847 * HOL/datatype
   848   Each datatype `t' now comes with a theorem `split_t_case' of the form
   849 
   850   P(t_case f1 ... fn x) =
   851      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   852         ...
   853        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   854      )
   855 
   856   and a theorem `split_t_case_asm' 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   which can be added to a simpset via `addsplits'. The existing theorems
   864   expand_list_case and expand_option_case have been renamed to
   865   split_list_case and split_option_case.
   866 
   867 * HOL/Arithmetic:
   868   - `pred n' is automatically converted to `n-1'.
   869     Users are strongly encouraged not to use `pred' any longer,
   870     because it will disappear altogether at some point.
   871   - Users are strongly encouraged to write "0 < n" rather than
   872     "n ~= 0". Theorems and proof tools have been modified towards this
   873     `standard'.
   874 
   875 * HOL/Lists:
   876   the function "set_of_list" has been renamed "set" (and its theorems too);
   877   the function "nth" now takes its arguments in the reverse order and
   878   has acquired the infix notation "!" as in "xs!n".
   879 
   880 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   881 
   882 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   883   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   884 
   885 * HOL/record: extensible records with schematic structural subtyping
   886 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   887 still lacks various theorems and concrete record syntax;
   888 
   889 
   890 *** HOLCF ***
   891 
   892 * removed "axioms" and "generated by" sections;
   893 
   894 * replaced "ops" section by extended "consts" section, which is capable of
   895   handling the continuous function space "->" directly;
   896 
   897 * domain package:
   898   . proves theorems immediately and stores them in the theory,
   899   . creates hierachical name space,
   900   . now uses normal mixfix annotations (instead of cinfix...),
   901   . minor changes to some names and values (for consistency),
   902   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   903   . separator between mutual domain defs: changed "," to "and",
   904   . improved handling of sort constraints;  now they have to
   905     appear on the left-hand side of the equations only;
   906 
   907 * fixed LAM <x,y,zs>.b syntax;
   908 
   909 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   910 adm (%x. P (t x)), where P is chainfinite and t continuous;
   911 
   912 
   913 *** FOL and ZF ***
   914 
   915 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   916   with `addloop' of the simplifier to faciliate case splitting in premises.
   917 
   918 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   919 in HOL, they strip ALL and --> from proved theorems;
   920 
   921 
   922 
   923 New in Isabelle94-8 (May 1997)
   924 ------------------------------
   925 
   926 *** General Changes ***
   927 
   928 * new utilities to build / run / maintain Isabelle etc. (in parts
   929 still somewhat experimental); old Makefiles etc. still functional;
   930 
   931 * new 'Isabelle System Manual';
   932 
   933 * INSTALL text, together with ./configure and ./build scripts;
   934 
   935 * reimplemented type inference for greater efficiency, better error
   936 messages and clean internal interface;
   937 
   938 * prlim command for dealing with lots of subgoals (an easier way of
   939 setting goals_limit);
   940 
   941 
   942 *** Syntax ***
   943 
   944 * supports alternative (named) syntax tables (parser and pretty
   945 printer); internal interface is provided by add_modesyntax(_i);
   946 
   947 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   948 be used in conjunction with the Isabelle symbol font; uses the
   949 "symbols" syntax table;
   950 
   951 * added token_translation interface (may translate name tokens in
   952 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   953 the current print_mode); IMPORTANT: user print translation functions
   954 are responsible for marking newly introduced bounds
   955 (Syntax.mark_boundT);
   956 
   957 * token translations for modes "xterm" and "xterm_color" that display
   958 names in bold, underline etc. or colors (which requires a color
   959 version of xterm);
   960 
   961 * infixes may now be declared with names independent of their syntax;
   962 
   963 * added typed_print_translation (like print_translation, but may
   964 access type of constant);
   965 
   966 
   967 *** Classical Reasoner ***
   968 
   969 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   970 some limitations.  Blast_tac...
   971   + ignores addss, addbefore, addafter; this restriction is intrinsic
   972   + ignores elimination rules that don't have the correct format
   973         (the conclusion MUST be a formula variable)
   974   + ignores types, which can make HOL proofs fail
   975   + rules must not require higher-order unification, e.g. apply_type in ZF
   976     [message "Function Var's argument not a bound variable" relates to this]
   977   + its proof strategy is more general but can actually be slower
   978 
   979 * substitution with equality assumptions no longer permutes other
   980 assumptions;
   981 
   982 * minor changes in semantics of addafter (now called addaltern); renamed
   983 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   984 (and access functions for it);
   985 
   986 * improved combination of classical reasoner and simplifier:
   987   + functions for handling clasimpsets
   988   + improvement of addss: now the simplifier is called _after_ the
   989     safe steps.
   990   + safe variant of addss called addSss: uses safe simplifications
   991     _during_ the safe steps. It is more complete as it allows multiple
   992     instantiations of unknowns (e.g. with slow_tac).
   993 
   994 *** Simplifier ***
   995 
   996 * added interface for simplification procedures (functions that
   997 produce *proven* rewrite rules on the fly, depending on current
   998 redex);
   999 
  1000 * ordering on terms as parameter (used for ordered rewriting);
  1001 
  1002 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1003 
  1004 * the solver is now split into a safe and an unsafe part.
  1005 This should be invisible for the normal user, except that the
  1006 functions setsolver and addsolver have been renamed to setSolver and
  1007 addSolver; added safe_asm_full_simp_tac;
  1008 
  1009 
  1010 *** HOL ***
  1011 
  1012 * a generic induction tactic `induct_tac' which works for all datatypes and
  1013 also for type `nat';
  1014 
  1015 * a generic case distinction tactic `exhaust_tac' which works for all
  1016 datatypes and also for type `nat';
  1017 
  1018 * each datatype comes with a function `size';
  1019 
  1020 * patterns in case expressions allow tuple patterns as arguments to
  1021 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1022 
  1023 * primrec now also works with type nat;
  1024 
  1025 * recdef: a new declaration form, allows general recursive functions to be
  1026 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1027 
  1028 * the constant for negation has been renamed from "not" to "Not" to
  1029 harmonize with FOL, ZF, LK, etc.;
  1030 
  1031 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1032 infinite lists;
  1033 
  1034 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1035 
  1036 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1037 problems in commutative rings, using axiomatic type classes for + and *;
  1038 
  1039 * more examples in HOL/MiniML and HOL/Auth;
  1040 
  1041 * more default rewrite rules for quantifiers, union/intersection;
  1042 
  1043 * a new constant `arbitrary == @x.False';
  1044 
  1045 * HOLCF/IOA replaces old HOL/IOA;
  1046 
  1047 * HOLCF changes: derived all rules and arities
  1048   + axiomatic type classes instead of classes
  1049   + typedef instead of faking type definitions
  1050   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1051   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1052   + eliminated the types void, one, tr
  1053   + use unit lift and bool lift (with translations) instead of one and tr
  1054   + eliminated blift from Lift3.thy (use Def instead of blift)
  1055   all eliminated rules are derived as theorems --> no visible changes ;
  1056 
  1057 
  1058 *** ZF ***
  1059 
  1060 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1061 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1062 as ZF_cs addSIs [equalityI];
  1063 
  1064 
  1065 
  1066 New in Isabelle94-7 (November 96)
  1067 ---------------------------------
  1068 
  1069 * allowing negative levels (as offsets) in prlev and choplev;
  1070 
  1071 * super-linear speedup for large simplifications;
  1072 
  1073 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1074 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1075 FAIL); can suppress it using the command Delsimps (ex_simps @
  1076 all_simps); De Morgan laws are also now included, by default;
  1077 
  1078 * improved printing of ==>  :  ~:
  1079 
  1080 * new object-logic "Sequents" adds linear logic, while replacing LK
  1081 and Modal (thanks to Sara Kalvala);
  1082 
  1083 * HOL/Auth: correctness proofs for authentication protocols;
  1084 
  1085 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1086 examples on HOL/Auth);
  1087 
  1088 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1089 the rewriter and classical reasoner simultaneously;
  1090 
  1091 * function uresult no longer returns theorems in "standard" format;
  1092 regain previous version by: val uresult = standard o uresult;
  1093 
  1094 
  1095 
  1096 New in Isabelle94-6
  1097 -------------------
  1098 
  1099 * oracles -- these establish an interface between Isabelle and trusted
  1100 external reasoners, which may deliver results as theorems;
  1101 
  1102 * proof objects (in particular record all uses of oracles);
  1103 
  1104 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1105 
  1106 * "constdefs" section in theory files;
  1107 
  1108 * "primrec" section (HOL) no longer requires names;
  1109 
  1110 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1111 
  1112 
  1113 
  1114 New in Isabelle94-5
  1115 -------------------
  1116 
  1117 * reduced space requirements;
  1118 
  1119 * automatic HTML generation from theories;
  1120 
  1121 * theory files no longer require "..." (quotes) around most types;
  1122 
  1123 * new examples, including two proofs of the Church-Rosser theorem;
  1124 
  1125 * non-curried (1994) version of HOL is no longer distributed;
  1126 
  1127 
  1128 
  1129 New in Isabelle94-4
  1130 -------------------
  1131 
  1132 * greatly reduced space requirements;
  1133 
  1134 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1135 
  1136 * searchable theorem database (see the section "Retrieving theorems" on
  1137 page 8 of the Reference Manual);
  1138 
  1139 * new examples, including Grabczewski's monumental case study of the
  1140 Axiom of Choice;
  1141 
  1142 * The previous version of HOL renamed to Old_HOL;
  1143 
  1144 * The new version of HOL (previously called CHOL) uses a curried syntax
  1145 for functions.  Application looks like f a b instead of f(a,b);
  1146 
  1147 * Mutually recursive inductive definitions finally work in HOL;
  1148 
  1149 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1150 translates to the operator "split";
  1151 
  1152 
  1153 
  1154 New in Isabelle94-3
  1155 -------------------
  1156 
  1157 * new infix operator, addss, allowing the classical reasoner to
  1158 perform simplification at each step of its search.  Example:
  1159         fast_tac (cs addss ss)
  1160 
  1161 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1162 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1163 look like (a,b) instead of <a,b>;
  1164 
  1165 * PLEASE NOTE: CHOL will eventually replace HOL!
  1166 
  1167 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1168 It translates to the operator "split".  A new theory of integers is available;
  1169 
  1170 * In ZF, integer numerals now denote two's-complement binary integers.
  1171 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1172 
  1173 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1174 of the Axiom of Choice;
  1175 
  1176 
  1177 
  1178 New in Isabelle94-2
  1179 -------------------
  1180 
  1181 * Significantly faster resolution;
  1182 
  1183 * the different sections in a .thy file can now be mixed and repeated
  1184 freely;
  1185 
  1186 * Database of theorems for FOL, HOL and ZF.  New
  1187 commands including qed, qed_goal and bind_thm store theorems in the database.
  1188 
  1189 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1190 a given theory (thms_of), or find out what theory a theorem was proved in
  1191 (theory_of_thm);
  1192 
  1193 * Bugs fixed in the inductive definition and datatype packages;
  1194 
  1195 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1196 and HOL_dup_cs obsolete;
  1197 
  1198 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1199 have been removed;
  1200 
  1201 * Simpler definition of function space in ZF;
  1202 
  1203 * new results about cardinal and ordinal arithmetic in ZF;
  1204 
  1205 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1206 types;
  1207 
  1208 
  1209 $Id$