NEWS
author nipkow
Fri May 01 11:43:38 1998 +0200 (1998-05-01)
changeset 4880 312115d20c45
parent 4879 58656c6a3551
child 4899 447d6b2956ba
permissions -rw-r--r--
*** empty log message ***
     1 
     2 Isabelle NEWS -- history of user-visible changes
     3 ================================================
     4 
     5 New in Isabelle??? (FIXME)
     6 --------------------------
     7 
     8 *** General Changes ***
     9 
    10 * Simplifier:
    11 
    12  -Asm_full_simp_tac is now more aggressive:
    13   1. It will sometimes reorient premises if that increases their power to
    14      simplify.
    15   2. It does no longer proceed strictly from left to right but may also
    16      rotate premises to achieve further simplification.
    17   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    18   old Asm_full_simp_tac in that it does not rotate premises.
    19 
    20 * Changed wrapper mechanism for the classical reasoner now allows for
    21 selected deletion of wrappers, by introduction of names for wrapper
    22 functionals.  This implies that addbefore, addSbefore, addaltern, and
    23 addSaltern now take a pair (name, tactic) as argument, and that adding
    24 two tactics with the same name overwrites the first one (emitting a
    25 warning).
    26   type wrapper = (int -> tactic) -> (int -> tactic)
    27   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    28   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    29   delWrapper, delSWrapper: claset *  string            -> claset
    30   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    31 
    32 * inductive definitions now handle disjunctive premises correctly (HOL
    33 and ZF);
    34 
    35 * new toplevel commands 'thm' and 'thms' for retrieving theorems from
    36 the current theory context;
    37 
    38 * new theory section 'nonterminals';
    39 
    40 * new theory section 'setup';
    41 
    42 
    43 *** HOL ***
    44 
    45 * new force_tac (and its derivations Force_tac, force): combines
    46 rewriting and classical reasoning (and whatever other tools) similarly
    47 to auto_tac, but is aimed to solve the given subgoal totally;
    48 
    49 * added option_map_eq_Some to simpset() and claset()
    50 
    51 * New directory HOL/UNITY: Chandy and Misra's UNITY formalism
    52 
    53 * split_all_tac is now much faster and fails if there is nothing to
    54 split.  Existing (fragile) proofs may require adaption because the
    55 order and the names of the automatically generated variables have
    56 changed.  split_all_tac has moved within claset() from usafe wrappers
    57 to safe wrappers, which means that !!-bound variables are splitted
    58 much more aggressively, and safe_tac and clarify_tac now split such
    59 variables.  If this splitting is not appropriate, use delSWrapper
    60 "split_all_tac".
    61 
    62 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
    63 
    64 * HOL/Arithmetic:
    65   
    66   - removed 'pred' (predecessor) function
    67   - generalized some theorems about n-1
    68   - Many new laws about "div" and "mod"
    69   - New laws about greatest common divisors (see theory ex/Primes)
    70 
    71 * HOL/Relation: renamed the relational operatotr r^-1 "converse"
    72 instead of "inverse";
    73 
    74 * recdef can now declare non-recursive functions, with {} supplied as
    75 the well-founded relation;
    76 
    77 * expand_if, expand_split, expand_sum_case and expand_nat_case are now called
    78   split_if, split_split, split_sum_case and split_nat_case
    79   (to go with add/delsplits).
    80 
    81 * Simplifier:
    82 
    83  -Rewrite rules for case distinctions can now be added permanently to the
    84   default simpset using Addsplits just like Addsimps. They can be removed via
    85   Delsplits just like Delsimps. Lower-case versions are also available.
    86 
    87  -The rule split_if is now part of the default simpset. This means that
    88   the simplifier will eliminate all ocurrences of if-then-else in the
    89   conclusion of a goal. To prevent this, you can either remove split_if
    90   completely from the default simpset by `Delsplits [split_if]' or
    91   remove it in a specific call of the simplifier using
    92   `... delsplits [split_if]'.
    93   You can also add/delete other case splitting rules to/from the default
    94   simpset: every datatype generates a suitable rule `split_t_case' (where t
    95   is the name of the datatype).
    96 
    97 * new theory Vimage (inverse image of a function, syntax f-``B);
    98 
    99 * many new identities for unions, intersections, set difference, etc.;
   100 
   101 *** ZF ***
   102 
   103 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   104 
   105 
   106 New in Isabelle98 (January 1998)
   107 --------------------------------
   108 
   109 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   110 
   111 * changed lexical syntax of terms / types: dots made part of long
   112 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   113 
   114 * simpset (and claset) reference variable replaced by functions
   115 simpset / simpset_ref;
   116 
   117 * no longer supports theory aliases (via merge) and non-trivial
   118 implicit merge of thms' signatures;
   119 
   120 * most internal names of constants changed due to qualified names;
   121 
   122 * changed Pure/Sequence interface (see Pure/seq.ML);
   123 
   124 
   125 *** General Changes ***
   126 
   127 * hierachically structured name spaces (for consts, types, axms, thms
   128 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   129 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   130 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   131 long_names for fully qualified output names; NOTE: ML programs
   132 (special tactics, packages etc.) referring to internal names may have
   133 to be adapted to cope with fully qualified names; in case of severe
   134 backward campatibility problems try setting 'global_names' at compile
   135 time to have enrything declared within a flat name space; one may also
   136 fine tune name declarations in theories via the 'global' and 'local'
   137 section;
   138 
   139 * reimplemented the implicit simpset and claset using the new anytype
   140 data filed in signatures; references simpset:simpset ref etc. are
   141 replaced by functions simpset:unit->simpset and
   142 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   143 to patch your ML files accordingly;
   144 
   145 * HTML output now includes theory graph data for display with Java
   146 applet or isatool browser; data generated automatically via isatool
   147 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   148 
   149 * defs may now be conditional; improved rewrite_goals_tac to handle
   150 conditional equations;
   151 
   152 * defs now admits additional type arguments, using TYPE('a) syntax;
   153 
   154 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   155 creates a new theory node; implicit merge of thms' signatures is
   156 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   157 transfer:theory->thm->thm in (rare) cases;
   158 
   159 * improved handling of draft signatures / theories; draft thms (and
   160 ctyps, cterms) are automatically promoted to real ones;
   161 
   162 * slightly changed interfaces for oracles: admit many per theory, named
   163 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   164 
   165 * print_goals: optional output of const types (set show_consts and
   166 show_types);
   167 
   168 * improved output of warnings (###) and errors (***);
   169 
   170 * subgoal_tac displays a warning if the new subgoal has type variables;
   171 
   172 * removed old README and Makefiles;
   173 
   174 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   175 
   176 * removed obsolete init_pps and init_database;
   177 
   178 * deleted the obsolete tactical STATE, which was declared by
   179     fun STATE tacfun st = tacfun st st;
   180 
   181 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   182 (which abbreviates $HOME);
   183 
   184 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   185 use isatool fixseq to adapt your ML programs (this works for fully
   186 qualified references to the Sequence structure only!);
   187 
   188 * use_thy no longer requires writable current directory; it always
   189 reloads .ML *and* .thy file, if either one is out of date;
   190 
   191 
   192 *** Classical Reasoner ***
   193 
   194 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   195 tactics that use classical reasoning to simplify a subgoal without
   196 splitting it into several subgoals;
   197 
   198 * Safe_tac: like safe_tac but uses the default claset;
   199 
   200 
   201 *** Simplifier ***
   202 
   203 * added simplification meta rules:
   204     (asm_)(full_)simplify: simpset -> thm -> thm;
   205 
   206 * simplifier.ML no longer part of Pure -- has to be loaded by object
   207 logics (again);
   208 
   209 * added prems argument to simplification procedures;
   210 
   211 * HOL, FOL, ZF: added infix function `addsplits':
   212   instead of `<simpset> setloop (split_tac <thms>)'
   213   you can simply write `<simpset> addsplits <thms>'
   214 
   215 
   216 *** Syntax ***
   217 
   218 * TYPE('a) syntax for type reflection terms;
   219 
   220 * no longer handles consts with name "" -- declare as 'syntax' instead;
   221 
   222 * pretty printer: changed order of mixfix annotation preference (again!);
   223 
   224 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   225 
   226 
   227 *** HOL ***
   228 
   229 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   230   with `addloop' of the simplifier to faciliate case splitting in premises.
   231 
   232 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   233 
   234 * HOL/Auth: new protocol proofs including some for the Internet
   235   protocol TLS;
   236 
   237 * HOL/Map: new theory of `maps' a la VDM;
   238 
   239 * HOL/simplifier: simplification procedures nat_cancel_sums for
   240 cancelling out common nat summands from =, <, <= (in)equalities, or
   241 differences; simplification procedures nat_cancel_factor for
   242 cancelling common factor from =, <, <= (in)equalities over natural
   243 sums; nat_cancel contains both kinds of procedures, it is installed by
   244 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   245 
   246 * HOL/simplifier: terms of the form
   247   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   248   are rewritten to
   249   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   250   and those of the form
   251   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   252   are rewritten to
   253   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   254 
   255 * HOL/datatype
   256   Each datatype `t' now comes with a theorem `split_t_case' of the form
   257 
   258   P(t_case f1 ... fn x) =
   259      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   260         ...
   261        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   262      )
   263 
   264   which can be added to a simpset via `addsplits'. The existing theorems
   265   expand_list_case and expand_option_case have been renamed to
   266   split_list_case and split_option_case.
   267 
   268   Additionally, there is a theorem `split_t_case_asm' of the form
   269 
   270   P(t_case f1 ... fn x) =
   271     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   272         ...
   273        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   274      )
   275 
   276   it be used with the new `split_asm_tac'.
   277 
   278 * HOL/Arithmetic:
   279   - `pred n' is automatically converted to `n-1'.
   280     Users are strongly encouraged not to use `pred' any longer,
   281     because it will disappear altogether at some point.
   282   - Users are strongly encouraged to write "0 < n" rather than
   283     "n ~= 0". Theorems and proof tools have been modified towards this
   284     `standard'.
   285 
   286 * HOL/Lists:
   287   the function "set_of_list" has been renamed "set" (and its theorems too);
   288   the function "nth" now takes its arguments in the reverse order and
   289   has acquired the infix notation "!" as in "xs!n".
   290 
   291 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   292 
   293 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   294   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   295 
   296 * HOL/record: extensible records with schematic structural subtyping
   297 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   298 still lacks various theorems and concrete record syntax;
   299 
   300 
   301 *** HOLCF ***
   302 
   303 * removed "axioms" and "generated by" sections;
   304 
   305 * replaced "ops" section by extended "consts" section, which is capable of
   306   handling the continuous function space "->" directly;
   307 
   308 * domain package:
   309   . proves theorems immediately and stores them in the theory,
   310   . creates hierachical name space,
   311   . now uses normal mixfix annotations (instead of cinfix...),
   312   . minor changes to some names and values (for consistency),
   313   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   314   . separator between mutual domain defs: changed "," to "and",
   315   . improved handling of sort constraints;  now they have to
   316     appear on the left-hand side of the equations only;
   317 
   318 * fixed LAM <x,y,zs>.b syntax;
   319 
   320 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   321 adm (%x. P (t x)), where P is chainfinite and t continuous;
   322 
   323 
   324 *** FOL and ZF ***
   325 
   326 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   327   with `addloop' of the simplifier to faciliate case splitting in premises.
   328 
   329 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   330 in HOL, they strip ALL and --> from proved theorems;
   331 
   332 
   333 
   334 New in Isabelle94-8 (May 1997)
   335 ------------------------------
   336 
   337 *** General Changes ***
   338 
   339 * new utilities to build / run / maintain Isabelle etc. (in parts
   340 still somewhat experimental); old Makefiles etc. still functional;
   341 
   342 * new 'Isabelle System Manual';
   343 
   344 * INSTALL text, together with ./configure and ./build scripts;
   345 
   346 * reimplemented type inference for greater efficiency, better error
   347 messages and clean internal interface;
   348 
   349 * prlim command for dealing with lots of subgoals (an easier way of
   350 setting goals_limit);
   351 
   352 
   353 *** Syntax ***
   354 
   355 * supports alternative (named) syntax tables (parser and pretty
   356 printer); internal interface is provided by add_modesyntax(_i);
   357 
   358 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   359 be used in conjunction with the Isabelle symbol font; uses the
   360 "symbols" syntax table;
   361 
   362 * added token_translation interface (may translate name tokens in
   363 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   364 the current print_mode); IMPORTANT: user print translation functions
   365 are responsible for marking newly introduced bounds
   366 (Syntax.mark_boundT);
   367 
   368 * token translations for modes "xterm" and "xterm_color" that display
   369 names in bold, underline etc. or colors (which requires a color
   370 version of xterm);
   371 
   372 * infixes may now be declared with names independent of their syntax;
   373 
   374 * added typed_print_translation (like print_translation, but may
   375 access type of constant);
   376 
   377 
   378 *** Classical Reasoner ***
   379 
   380 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   381 some limitations.  Blast_tac...
   382   + ignores addss, addbefore, addafter; this restriction is intrinsic
   383   + ignores elimination rules that don't have the correct format
   384 	(the conclusion MUST be a formula variable)
   385   + ignores types, which can make HOL proofs fail
   386   + rules must not require higher-order unification, e.g. apply_type in ZF
   387     [message "Function Var's argument not a bound variable" relates to this]
   388   + its proof strategy is more general but can actually be slower
   389 
   390 * substitution with equality assumptions no longer permutes other
   391 assumptions;
   392 
   393 * minor changes in semantics of addafter (now called addaltern); renamed
   394 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   395 (and access functions for it);
   396 
   397 * improved combination of classical reasoner and simplifier: 
   398   + functions for handling clasimpsets
   399   + improvement of addss: now the simplifier is called _after_ the
   400     safe steps.
   401   + safe variant of addss called addSss: uses safe simplifications
   402     _during_ the safe steps. It is more complete as it allows multiple 
   403     instantiations of unknowns (e.g. with slow_tac).
   404 
   405 *** Simplifier ***
   406 
   407 * added interface for simplification procedures (functions that
   408 produce *proven* rewrite rules on the fly, depending on current
   409 redex);
   410 
   411 * ordering on terms as parameter (used for ordered rewriting);
   412 
   413 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   414 
   415 * the solver is now split into a safe and an unsafe part.
   416 This should be invisible for the normal user, except that the
   417 functions setsolver and addsolver have been renamed to setSolver and
   418 addSolver; added safe_asm_full_simp_tac;
   419 
   420 
   421 *** HOL ***
   422 
   423 * a generic induction tactic `induct_tac' which works for all datatypes and
   424 also for type `nat';
   425 
   426 * a generic case distinction tactic `exhaust_tac' which works for all
   427 datatypes and also for type `nat';
   428 
   429 * each datatype comes with a function `size';
   430 
   431 * patterns in case expressions allow tuple patterns as arguments to
   432 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   433 
   434 * primrec now also works with type nat;
   435 
   436 * recdef: a new declaration form, allows general recursive functions to be
   437 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   438 
   439 * the constant for negation has been renamed from "not" to "Not" to
   440 harmonize with FOL, ZF, LK, etc.;
   441 
   442 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   443 infinite lists;
   444 
   445 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   446 
   447 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   448 problems in commutative rings, using axiomatic type classes for + and *;
   449 
   450 * more examples in HOL/MiniML and HOL/Auth;
   451 
   452 * more default rewrite rules for quantifiers, union/intersection;
   453 
   454 * a new constant `arbitrary == @x.False';
   455 
   456 * HOLCF/IOA replaces old HOL/IOA;
   457 
   458 * HOLCF changes: derived all rules and arities 
   459   + axiomatic type classes instead of classes 
   460   + typedef instead of faking type definitions
   461   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   462   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   463   + eliminated the types void, one, tr
   464   + use unit lift and bool lift (with translations) instead of one and tr
   465   + eliminated blift from Lift3.thy (use Def instead of blift)
   466   all eliminated rules are derived as theorems --> no visible changes ;
   467 
   468 
   469 *** ZF ***
   470 
   471 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   472 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   473 as ZF_cs addSIs [equalityI];
   474 
   475 
   476 
   477 New in Isabelle94-7 (November 96)
   478 ---------------------------------
   479 
   480 * allowing negative levels (as offsets) in prlev and choplev;
   481 
   482 * super-linear speedup for large simplifications;
   483 
   484 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   485 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   486 FAIL); can suppress it using the command Delsimps (ex_simps @
   487 all_simps); De Morgan laws are also now included, by default;
   488 
   489 * improved printing of ==>  :  ~:
   490 
   491 * new object-logic "Sequents" adds linear logic, while replacing LK
   492 and Modal (thanks to Sara Kalvala);
   493 
   494 * HOL/Auth: correctness proofs for authentication protocols;
   495 
   496 * HOL: new auto_tac combines rewriting and classical reasoning (many
   497 examples on HOL/Auth);
   498 
   499 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   500 the rewriter and classical reasoner simultaneously;
   501 
   502 * function uresult no longer returns theorems in "standard" format;
   503 regain previous version by: val uresult = standard o uresult;
   504 
   505 
   506 
   507 New in Isabelle94-6
   508 -------------------
   509 
   510 * oracles -- these establish an interface between Isabelle and trusted
   511 external reasoners, which may deliver results as theorems;
   512 
   513 * proof objects (in particular record all uses of oracles);
   514 
   515 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   516 
   517 * "constdefs" section in theory files;
   518 
   519 * "primrec" section (HOL) no longer requires names;
   520 
   521 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   522 
   523 
   524 
   525 New in Isabelle94-5
   526 -------------------
   527 
   528 * reduced space requirements;
   529 
   530 * automatic HTML generation from theories;
   531 
   532 * theory files no longer require "..." (quotes) around most types;
   533 
   534 * new examples, including two proofs of the Church-Rosser theorem;
   535 
   536 * non-curried (1994) version of HOL is no longer distributed;
   537 
   538 
   539 
   540 New in Isabelle94-4
   541 -------------------
   542 
   543 * greatly reduced space requirements;
   544 
   545 * theory files (.thy) no longer require \...\ escapes at line breaks;
   546 
   547 * searchable theorem database (see the section "Retrieving theorems" on 
   548 page 8 of the Reference Manual);
   549 
   550 * new examples, including Grabczewski's monumental case study of the
   551 Axiom of Choice;
   552 
   553 * The previous version of HOL renamed to Old_HOL;
   554 
   555 * The new version of HOL (previously called CHOL) uses a curried syntax 
   556 for functions.  Application looks like f a b instead of f(a,b);
   557 
   558 * Mutually recursive inductive definitions finally work in HOL;
   559 
   560 * In ZF, pattern-matching on tuples is now available in all abstractions and
   561 translates to the operator "split";
   562 
   563 
   564 
   565 New in Isabelle94-3
   566 -------------------
   567 
   568 * new infix operator, addss, allowing the classical reasoner to 
   569 perform simplification at each step of its search.  Example:
   570 	fast_tac (cs addss ss)
   571 
   572 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   573 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   574 look like (a,b) instead of <a,b>;
   575 
   576 * PLEASE NOTE: CHOL will eventually replace HOL!
   577 
   578 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   579 It translates to the operator "split".  A new theory of integers is available;
   580 
   581 * In ZF, integer numerals now denote two's-complement binary integers.
   582 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   583 
   584 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   585 of the Axiom of Choice;
   586 
   587 
   588 
   589 New in Isabelle94-2
   590 -------------------
   591 
   592 * Significantly faster resolution;  
   593 
   594 * the different sections in a .thy file can now be mixed and repeated
   595 freely;
   596 
   597 * Database of theorems for FOL, HOL and ZF.  New
   598 commands including qed, qed_goal and bind_thm store theorems in the database.
   599 
   600 * Simple database queries: return a named theorem (get_thm) or all theorems of
   601 a given theory (thms_of), or find out what theory a theorem was proved in
   602 (theory_of_thm);
   603 
   604 * Bugs fixed in the inductive definition and datatype packages;
   605 
   606 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   607 and HOL_dup_cs obsolete;
   608 
   609 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   610 have been removed;
   611 
   612 * Simpler definition of function space in ZF;
   613 
   614 * new results about cardinal and ordinal arithmetic in ZF;
   615 
   616 * 'subtype' facility in HOL for introducing new types as subsets of existing
   617 types;
   618 
   619 
   620 $Id$