NEWS
author wenzelm
Wed Apr 29 11:41:36 1998 +0200 (1998-04-29)
changeset 4869 f3d30c02c1db
parent 4858 4b15e9e1b3a5
child 4879 58656c6a3551
permissions -rw-r--r--
new theory section 'setup';
     1 
     2 Isabelle NEWS -- history of user-visible changes
     3 ================================================
     4 
     5 New in Isabelle??? (FIXME)
     6 --------------------------
     7 
     8 *** General Changes ***
     9 
    10 * Changed wrapper mechanism for the classical reasoner now allows for
    11 selected deletion of wrappers, by introduction of names for wrapper
    12 functionals.  This implies that addbefore, addSbefore, addaltern, and
    13 addSaltern now take a pair (name, tactic) as argument, and that adding
    14 two tactics with the same name overwrites the first one (emitting a
    15 warning).
    16   type wrapper = (int -> tactic) -> (int -> tactic)
    17   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    18   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    19   delWrapper, delSWrapper: claset *  string            -> claset
    20   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    21 
    22 * inductive definitions now handle disjunctive premises correctly (HOL
    23 and ZF);
    24 
    25 * new toplevel commands 'thm' and 'thms' for retrieving theorems from
    26 the current theory context;
    27 
    28 * new theory section 'nonterminals';
    29 
    30 * new theory section 'setup';
    31 
    32 
    33 *** HOL ***
    34 
    35 * new force_tac (and its derivations Force_tac, force): combines
    36 rewriting and classical reasoning (and whatever other tools) similarly
    37 to auto_tac, but is aimed to solve the given subgoal totally;
    38 
    39 * added option_map_eq_Some to simpset() and claset()
    40 
    41 * New directory HOL/UNITY: Chandy and Misra's UNITY formalism
    42 
    43 * split_all_tac is now much faster and fails if there is nothing to
    44 split.  Existing (fragile) proofs may require adaption because the
    45 order and the names of the automatically generated variables have
    46 changed.  split_all_tac has moved within claset() from usafe wrappers
    47 to safe wrappers, which means that !!-bound variables are splitted
    48 much more aggressively, and safe_tac and clarify_tac now split such
    49 variables.  If this splitting is not appropriate, use delSWrapper
    50 "split_all_tac".
    51 
    52 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
    53 
    54 * HOL/Arithmetic:
    55   
    56   - removed 'pred' (predecessor) function
    57   - generalized some theorems about n-1
    58   - Many new laws about "div" and "mod"
    59   - New laws about greatest common divisors (see theory ex/Primes)
    60 
    61 * HOL/Relation: renamed the relational operatotr r^-1 "converse"
    62 instead of "inverse";
    63 
    64 * recdef can now declare non-recursive functions, with {} supplied as
    65 the well-founded relation;
    66 
    67 * Simplifier:
    68 
    69  -Rewrite rules for case distinctions can now be added permanently to the
    70   default simpset using Addsplits just like Addsimps. They can be removed via
    71   Delsplits just like Delsimps. Lower-case versions are also available.
    72 
    73  -The rule expand_if is now part of the default simpset. This means that
    74   the simplifier will eliminate all ocurrences of if-then-else in the
    75   conclusion of a goal. To prevent this, you can either remove expand_if
    76   completely from the default simpset by `Delsplits [expand_if]' or
    77   remove it in a specific call of the simplifier using
    78   `... delsplits [expand_if]'.
    79   You can also add/delete other case splitting rules to/from the default
    80   simpset: every datatype generates a suitable rule `split_t_case' (where t
    81   is the name of the datatype).
    82 
    83  -Asm_full_simp_tac is now more aggressive:
    84   1. It will sometimes reorient premises if that increases their power to
    85      simplify.
    86   2. It does no longer proceed strictly from left to right but may also
    87      rotate premises to achieve further simplification.
    88   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    89   old Asm_full_simp_tac in that it does not rotate premises.
    90 
    91 * expand_if, expand_split, expand_sum_case and expand_nat_case are now called
    92   split_if, split_split, split_sum_case and split_nat_case
    93   (to go with add/delsplits).
    94 
    95 * new theory Vimage (inverse image of a function, syntax f-``B);
    96 
    97 * many new identities for unions, intersections, set difference, etc.;
    98 
    99 
   100 
   101 New in Isabelle98 (January 1998)
   102 --------------------------------
   103 
   104 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   105 
   106 * changed lexical syntax of terms / types: dots made part of long
   107 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   108 
   109 * simpset (and claset) reference variable replaced by functions
   110 simpset / simpset_ref;
   111 
   112 * no longer supports theory aliases (via merge) and non-trivial
   113 implicit merge of thms' signatures;
   114 
   115 * most internal names of constants changed due to qualified names;
   116 
   117 * changed Pure/Sequence interface (see Pure/seq.ML);
   118 
   119 
   120 *** General Changes ***
   121 
   122 * hierachically structured name spaces (for consts, types, axms, thms
   123 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   124 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   125 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   126 long_names for fully qualified output names; NOTE: ML programs
   127 (special tactics, packages etc.) referring to internal names may have
   128 to be adapted to cope with fully qualified names; in case of severe
   129 backward campatibility problems try setting 'global_names' at compile
   130 time to have enrything declared within a flat name space; one may also
   131 fine tune name declarations in theories via the 'global' and 'local'
   132 section;
   133 
   134 * reimplemented the implicit simpset and claset using the new anytype
   135 data filed in signatures; references simpset:simpset ref etc. are
   136 replaced by functions simpset:unit->simpset and
   137 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   138 to patch your ML files accordingly;
   139 
   140 * HTML output now includes theory graph data for display with Java
   141 applet or isatool browser; data generated automatically via isatool
   142 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   143 
   144 * defs may now be conditional; improved rewrite_goals_tac to handle
   145 conditional equations;
   146 
   147 * defs now admits additional type arguments, using TYPE('a) syntax;
   148 
   149 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   150 creates a new theory node; implicit merge of thms' signatures is
   151 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   152 transfer:theory->thm->thm in (rare) cases;
   153 
   154 * improved handling of draft signatures / theories; draft thms (and
   155 ctyps, cterms) are automatically promoted to real ones;
   156 
   157 * slightly changed interfaces for oracles: admit many per theory, named
   158 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   159 
   160 * print_goals: optional output of const types (set show_consts and
   161 show_types);
   162 
   163 * improved output of warnings (###) and errors (***);
   164 
   165 * subgoal_tac displays a warning if the new subgoal has type variables;
   166 
   167 * removed old README and Makefiles;
   168 
   169 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   170 
   171 * removed obsolete init_pps and init_database;
   172 
   173 * deleted the obsolete tactical STATE, which was declared by
   174     fun STATE tacfun st = tacfun st st;
   175 
   176 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   177 (which abbreviates $HOME);
   178 
   179 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   180 use isatool fixseq to adapt your ML programs (this works for fully
   181 qualified references to the Sequence structure only!);
   182 
   183 * use_thy no longer requires writable current directory; it always
   184 reloads .ML *and* .thy file, if either one is out of date;
   185 
   186 
   187 *** Classical Reasoner ***
   188 
   189 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   190 tactics that use classical reasoning to simplify a subgoal without
   191 splitting it into several subgoals;
   192 
   193 * Safe_tac: like safe_tac but uses the default claset;
   194 
   195 
   196 *** Simplifier ***
   197 
   198 * added simplification meta rules:
   199     (asm_)(full_)simplify: simpset -> thm -> thm;
   200 
   201 * simplifier.ML no longer part of Pure -- has to be loaded by object
   202 logics (again);
   203 
   204 * added prems argument to simplification procedures;
   205 
   206 * HOL, FOL, ZF: added infix function `addsplits':
   207   instead of `<simpset> setloop (split_tac <thms>)'
   208   you can simply write `<simpset> addsplits <thms>'
   209 
   210 
   211 *** Syntax ***
   212 
   213 * TYPE('a) syntax for type reflection terms;
   214 
   215 * no longer handles consts with name "" -- declare as 'syntax' instead;
   216 
   217 * pretty printer: changed order of mixfix annotation preference (again!);
   218 
   219 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   220 
   221 
   222 *** HOL ***
   223 
   224 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   225   with `addloop' of the simplifier to faciliate case splitting in premises.
   226 
   227 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   228 
   229 * HOL/Auth: new protocol proofs including some for the Internet
   230   protocol TLS;
   231 
   232 * HOL/Map: new theory of `maps' a la VDM;
   233 
   234 * HOL/simplifier: simplification procedures nat_cancel_sums for
   235 cancelling out common nat summands from =, <, <= (in)equalities, or
   236 differences; simplification procedures nat_cancel_factor for
   237 cancelling common factor from =, <, <= (in)equalities over natural
   238 sums; nat_cancel contains both kinds of procedures, it is installed by
   239 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   240 
   241 * HOL/simplifier: terms of the form
   242   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   243   are rewritten to
   244   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   245   and those of the form
   246   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   247   are rewritten to
   248   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   249 
   250 * HOL/datatype
   251   Each datatype `t' now comes with a theorem `split_t_case' of the form
   252 
   253   P(t_case f1 ... fn x) =
   254      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   255         ...
   256        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   257      )
   258 
   259   which can be added to a simpset via `addsplits'. The existing theorems
   260   expand_list_case and expand_option_case have been renamed to
   261   split_list_case and split_option_case.
   262 
   263   Additionally, there is a theorem `split_t_case_asm' of the form
   264 
   265   P(t_case f1 ... fn x) =
   266     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   267         ...
   268        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   269      )
   270 
   271   it be used with the new `split_asm_tac'.
   272 
   273 * HOL/Arithmetic:
   274   - `pred n' is automatically converted to `n-1'.
   275     Users are strongly encouraged not to use `pred' any longer,
   276     because it will disappear altogether at some point.
   277   - Users are strongly encouraged to write "0 < n" rather than
   278     "n ~= 0". Theorems and proof tools have been modified towards this
   279     `standard'.
   280 
   281 * HOL/Lists:
   282   the function "set_of_list" has been renamed "set" (and its theorems too);
   283   the function "nth" now takes its arguments in the reverse order and
   284   has acquired the infix notation "!" as in "xs!n".
   285 
   286 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   287 
   288 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   289   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   290 
   291 * HOL/record: extensible records with schematic structural subtyping
   292 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   293 still lacks various theorems and concrete record syntax;
   294 
   295 
   296 *** HOLCF ***
   297 
   298 * removed "axioms" and "generated by" sections;
   299 
   300 * replaced "ops" section by extended "consts" section, which is capable of
   301   handling the continuous function space "->" directly;
   302 
   303 * domain package:
   304   . proves theorems immediately and stores them in the theory,
   305   . creates hierachical name space,
   306   . now uses normal mixfix annotations (instead of cinfix...),
   307   . minor changes to some names and values (for consistency),
   308   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   309   . separator between mutual domain defs: changed "," to "and",
   310   . improved handling of sort constraints;  now they have to
   311     appear on the left-hand side of the equations only;
   312 
   313 * fixed LAM <x,y,zs>.b syntax;
   314 
   315 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   316 adm (%x. P (t x)), where P is chainfinite and t continuous;
   317 
   318 
   319 *** FOL and ZF ***
   320 
   321 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   322   with `addloop' of the simplifier to faciliate case splitting in premises.
   323 
   324 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   325 in HOL, they strip ALL and --> from proved theorems;
   326 
   327 
   328 
   329 New in Isabelle94-8 (May 1997)
   330 ------------------------------
   331 
   332 *** General Changes ***
   333 
   334 * new utilities to build / run / maintain Isabelle etc. (in parts
   335 still somewhat experimental); old Makefiles etc. still functional;
   336 
   337 * new 'Isabelle System Manual';
   338 
   339 * INSTALL text, together with ./configure and ./build scripts;
   340 
   341 * reimplemented type inference for greater efficiency, better error
   342 messages and clean internal interface;
   343 
   344 * prlim command for dealing with lots of subgoals (an easier way of
   345 setting goals_limit);
   346 
   347 
   348 *** Syntax ***
   349 
   350 * supports alternative (named) syntax tables (parser and pretty
   351 printer); internal interface is provided by add_modesyntax(_i);
   352 
   353 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   354 be used in conjunction with the Isabelle symbol font; uses the
   355 "symbols" syntax table;
   356 
   357 * added token_translation interface (may translate name tokens in
   358 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   359 the current print_mode); IMPORTANT: user print translation functions
   360 are responsible for marking newly introduced bounds
   361 (Syntax.mark_boundT);
   362 
   363 * token translations for modes "xterm" and "xterm_color" that display
   364 names in bold, underline etc. or colors (which requires a color
   365 version of xterm);
   366 
   367 * infixes may now be declared with names independent of their syntax;
   368 
   369 * added typed_print_translation (like print_translation, but may
   370 access type of constant);
   371 
   372 
   373 *** Classical Reasoner ***
   374 
   375 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   376 some limitations.  Blast_tac...
   377   + ignores addss, addbefore, addafter; this restriction is intrinsic
   378   + ignores elimination rules that don't have the correct format
   379 	(the conclusion MUST be a formula variable)
   380   + ignores types, which can make HOL proofs fail
   381   + rules must not require higher-order unification, e.g. apply_type in ZF
   382     [message "Function Var's argument not a bound variable" relates to this]
   383   + its proof strategy is more general but can actually be slower
   384 
   385 * substitution with equality assumptions no longer permutes other
   386 assumptions;
   387 
   388 * minor changes in semantics of addafter (now called addaltern); renamed
   389 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   390 (and access functions for it);
   391 
   392 * improved combination of classical reasoner and simplifier: 
   393   + functions for handling clasimpsets
   394   + improvement of addss: now the simplifier is called _after_ the
   395     safe steps.
   396   + safe variant of addss called addSss: uses safe simplifications
   397     _during_ the safe steps. It is more complete as it allows multiple 
   398     instantiations of unknowns (e.g. with slow_tac).
   399 
   400 *** Simplifier ***
   401 
   402 * added interface for simplification procedures (functions that
   403 produce *proven* rewrite rules on the fly, depending on current
   404 redex);
   405 
   406 * ordering on terms as parameter (used for ordered rewriting);
   407 
   408 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   409 
   410 * the solver is now split into a safe and an unsafe part.
   411 This should be invisible for the normal user, except that the
   412 functions setsolver and addsolver have been renamed to setSolver and
   413 addSolver; added safe_asm_full_simp_tac;
   414 
   415 
   416 *** HOL ***
   417 
   418 * a generic induction tactic `induct_tac' which works for all datatypes and
   419 also for type `nat';
   420 
   421 * a generic case distinction tactic `exhaust_tac' which works for all
   422 datatypes and also for type `nat';
   423 
   424 * each datatype comes with a function `size';
   425 
   426 * patterns in case expressions allow tuple patterns as arguments to
   427 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   428 
   429 * primrec now also works with type nat;
   430 
   431 * recdef: a new declaration form, allows general recursive functions to be
   432 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   433 
   434 * the constant for negation has been renamed from "not" to "Not" to
   435 harmonize with FOL, ZF, LK, etc.;
   436 
   437 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   438 infinite lists;
   439 
   440 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   441 
   442 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   443 problems in commutative rings, using axiomatic type classes for + and *;
   444 
   445 * more examples in HOL/MiniML and HOL/Auth;
   446 
   447 * more default rewrite rules for quantifiers, union/intersection;
   448 
   449 * a new constant `arbitrary == @x.False';
   450 
   451 * HOLCF/IOA replaces old HOL/IOA;
   452 
   453 * HOLCF changes: derived all rules and arities 
   454   + axiomatic type classes instead of classes 
   455   + typedef instead of faking type definitions
   456   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   457   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   458   + eliminated the types void, one, tr
   459   + use unit lift and bool lift (with translations) instead of one and tr
   460   + eliminated blift from Lift3.thy (use Def instead of blift)
   461   all eliminated rules are derived as theorems --> no visible changes ;
   462 
   463 
   464 *** ZF ***
   465 
   466 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   467 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   468 as ZF_cs addSIs [equalityI];
   469 
   470 
   471 
   472 New in Isabelle94-7 (November 96)
   473 ---------------------------------
   474 
   475 * allowing negative levels (as offsets) in prlev and choplev;
   476 
   477 * super-linear speedup for large simplifications;
   478 
   479 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   480 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   481 FAIL); can suppress it using the command Delsimps (ex_simps @
   482 all_simps); De Morgan laws are also now included, by default;
   483 
   484 * improved printing of ==>  :  ~:
   485 
   486 * new object-logic "Sequents" adds linear logic, while replacing LK
   487 and Modal (thanks to Sara Kalvala);
   488 
   489 * HOL/Auth: correctness proofs for authentication protocols;
   490 
   491 * HOL: new auto_tac combines rewriting and classical reasoning (many
   492 examples on HOL/Auth);
   493 
   494 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   495 the rewriter and classical reasoner simultaneously;
   496 
   497 * function uresult no longer returns theorems in "standard" format;
   498 regain previous version by: val uresult = standard o uresult;
   499 
   500 
   501 
   502 New in Isabelle94-6
   503 -------------------
   504 
   505 * oracles -- these establish an interface between Isabelle and trusted
   506 external reasoners, which may deliver results as theorems;
   507 
   508 * proof objects (in particular record all uses of oracles);
   509 
   510 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   511 
   512 * "constdefs" section in theory files;
   513 
   514 * "primrec" section (HOL) no longer requires names;
   515 
   516 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   517 
   518 
   519 
   520 New in Isabelle94-5
   521 -------------------
   522 
   523 * reduced space requirements;
   524 
   525 * automatic HTML generation from theories;
   526 
   527 * theory files no longer require "..." (quotes) around most types;
   528 
   529 * new examples, including two proofs of the Church-Rosser theorem;
   530 
   531 * non-curried (1994) version of HOL is no longer distributed;
   532 
   533 
   534 
   535 New in Isabelle94-4
   536 -------------------
   537 
   538 * greatly reduced space requirements;
   539 
   540 * theory files (.thy) no longer require \...\ escapes at line breaks;
   541 
   542 * searchable theorem database (see the section "Retrieving theorems" on 
   543 page 8 of the Reference Manual);
   544 
   545 * new examples, including Grabczewski's monumental case study of the
   546 Axiom of Choice;
   547 
   548 * The previous version of HOL renamed to Old_HOL;
   549 
   550 * The new version of HOL (previously called CHOL) uses a curried syntax 
   551 for functions.  Application looks like f a b instead of f(a,b);
   552 
   553 * Mutually recursive inductive definitions finally work in HOL;
   554 
   555 * In ZF, pattern-matching on tuples is now available in all abstractions and
   556 translates to the operator "split";
   557 
   558 
   559 
   560 New in Isabelle94-3
   561 -------------------
   562 
   563 * new infix operator, addss, allowing the classical reasoner to 
   564 perform simplification at each step of its search.  Example:
   565 	fast_tac (cs addss ss)
   566 
   567 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   568 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   569 look like (a,b) instead of <a,b>;
   570 
   571 * PLEASE NOTE: CHOL will eventually replace HOL!
   572 
   573 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   574 It translates to the operator "split".  A new theory of integers is available;
   575 
   576 * In ZF, integer numerals now denote two's-complement binary integers.
   577 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   578 
   579 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   580 of the Axiom of Choice;
   581 
   582 
   583 
   584 New in Isabelle94-2
   585 -------------------
   586 
   587 * Significantly faster resolution;  
   588 
   589 * the different sections in a .thy file can now be mixed and repeated
   590 freely;
   591 
   592 * Database of theorems for FOL, HOL and ZF.  New
   593 commands including qed, qed_goal and bind_thm store theorems in the database.
   594 
   595 * Simple database queries: return a named theorem (get_thm) or all theorems of
   596 a given theory (thms_of), or find out what theory a theorem was proved in
   597 (theory_of_thm);
   598 
   599 * Bugs fixed in the inductive definition and datatype packages;
   600 
   601 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   602 and HOL_dup_cs obsolete;
   603 
   604 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   605 have been removed;
   606 
   607 * Simpler definition of function space in ZF;
   608 
   609 * new results about cardinal and ordinal arithmetic in ZF;
   610 
   611 * 'subtype' facility in HOL for introducing new types as subsets of existing
   612 types;
   613 
   614 
   615 $Id$