NEWS
author wenzelm
Thu May 28 12:24:05 1998 +0200 (1998-05-28)
changeset 4981 9703ba0e9122
parent 4930 89271bc4e7ed
child 5002 7b4c2a153738
permissions -rw-r--r--
tuned header;
     1 
     2 Isabelle NEWS -- history of user-visible changes
     3 ================================================
     4 
     5 New in this Isabelle version
     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 * HOL/record: now includes concrete syntax for record terms (still
    46 lacks important theorems, like surjective pairing and split);
    47 
    48 * new force_tac (and its derivations Force_tac, force): combines
    49 rewriting and classical reasoning (and whatever other tools) similarly
    50 to auto_tac, but is aimed to solve the given subgoal totally;
    51 
    52 * added option_map_eq_Some to simpset() and claset()
    53 
    54 * New theory HOL/Update of function updates:
    55   f[a:=b] == %x. if x=a then b else f x
    56 
    57 * New directory HOL/UNITY: Chandy and Misra's UNITY formalism
    58 
    59 * split_all_tac is now much faster and fails if there is nothing to
    60 split.  Existing (fragile) proofs may require adaption because the
    61 order and the names of the automatically generated variables have
    62 changed.  split_all_tac has moved within claset() from usafe wrappers
    63 to safe wrappers, which means that !!-bound variables are splitted
    64 much more aggressively, and safe_tac and clarify_tac now split such
    65 variables.  If this splitting is not appropriate, use delSWrapper
    66 "split_all_tac".
    67 
    68 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
    69 
    70 * HOL/Arithmetic:
    71   
    72   - removed 'pred' (predecessor) function
    73   - generalized some theorems about n-1
    74   - Many new laws about "div" and "mod"
    75   - New laws about greatest common divisors (see theory ex/Primes)
    76 
    77 * HOL/Relation: renamed the relational operatotr r^-1 "converse"
    78 instead of "inverse";
    79 
    80 * recdef can now declare non-recursive functions, with {} supplied as
    81 the well-founded relation;
    82 
    83 * expand_if, expand_split, expand_sum_case and expand_nat_case are now called
    84   split_if, split_split, split_sum_case and split_nat_case
    85   (to go with add/delsplits).
    86 
    87 * Simplifier:
    88 
    89  -Rewrite rules for case distinctions can now be added permanently to the
    90   default simpset using Addsplits just like Addsimps. They can be removed via
    91   Delsplits just like Delsimps. Lower-case versions are also available.
    92 
    93  -The rule split_if is now part of the default simpset. This means that
    94   the simplifier will eliminate all ocurrences of if-then-else in the
    95   conclusion of a goal. To prevent this, you can either remove split_if
    96   completely from the default simpset by `Delsplits [split_if]' or
    97   remove it in a specific call of the simplifier using
    98   `... delsplits [split_if]'.
    99   You can also add/delete other case splitting rules to/from the default
   100   simpset: every datatype generates suitable rules `split_t_case' and
   101   `split_t_case_asm' (where t is the name of the datatype).
   102 
   103 * new theory Vimage (inverse image of a function, syntax f-``B);
   104 
   105 * many new identities for unions, intersections, set difference, etc.;
   106 
   107 *** ZF ***
   108 
   109 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   110 
   111 
   112 New in Isabelle98 (January 1998)
   113 --------------------------------
   114 
   115 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   116 
   117 * changed lexical syntax of terms / types: dots made part of long
   118 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   119 
   120 * simpset (and claset) reference variable replaced by functions
   121 simpset / simpset_ref;
   122 
   123 * no longer supports theory aliases (via merge) and non-trivial
   124 implicit merge of thms' signatures;
   125 
   126 * most internal names of constants changed due to qualified names;
   127 
   128 * changed Pure/Sequence interface (see Pure/seq.ML);
   129 
   130 
   131 *** General Changes ***
   132 
   133 * hierachically structured name spaces (for consts, types, axms, thms
   134 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   135 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   136 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   137 long_names for fully qualified output names; NOTE: ML programs
   138 (special tactics, packages etc.) referring to internal names may have
   139 to be adapted to cope with fully qualified names; in case of severe
   140 backward campatibility problems try setting 'global_names' at compile
   141 time to have enrything declared within a flat name space; one may also
   142 fine tune name declarations in theories via the 'global' and 'local'
   143 section;
   144 
   145 * reimplemented the implicit simpset and claset using the new anytype
   146 data filed in signatures; references simpset:simpset ref etc. are
   147 replaced by functions simpset:unit->simpset and
   148 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   149 to patch your ML files accordingly;
   150 
   151 * HTML output now includes theory graph data for display with Java
   152 applet or isatool browser; data generated automatically via isatool
   153 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   154 
   155 * defs may now be conditional; improved rewrite_goals_tac to handle
   156 conditional equations;
   157 
   158 * defs now admits additional type arguments, using TYPE('a) syntax;
   159 
   160 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   161 creates a new theory node; implicit merge of thms' signatures is
   162 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   163 transfer:theory->thm->thm in (rare) cases;
   164 
   165 * improved handling of draft signatures / theories; draft thms (and
   166 ctyps, cterms) are automatically promoted to real ones;
   167 
   168 * slightly changed interfaces for oracles: admit many per theory, named
   169 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   170 
   171 * print_goals: optional output of const types (set show_consts and
   172 show_types);
   173 
   174 * improved output of warnings (###) and errors (***);
   175 
   176 * subgoal_tac displays a warning if the new subgoal has type variables;
   177 
   178 * removed old README and Makefiles;
   179 
   180 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   181 
   182 * removed obsolete init_pps and init_database;
   183 
   184 * deleted the obsolete tactical STATE, which was declared by
   185     fun STATE tacfun st = tacfun st st;
   186 
   187 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   188 (which abbreviates $HOME);
   189 
   190 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   191 use isatool fixseq to adapt your ML programs (this works for fully
   192 qualified references to the Sequence structure only!);
   193 
   194 * use_thy no longer requires writable current directory; it always
   195 reloads .ML *and* .thy file, if either one is out of date;
   196 
   197 
   198 *** Classical Reasoner ***
   199 
   200 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   201 tactics that use classical reasoning to simplify a subgoal without
   202 splitting it into several subgoals;
   203 
   204 * Safe_tac: like safe_tac but uses the default claset;
   205 
   206 
   207 *** Simplifier ***
   208 
   209 * added simplification meta rules:
   210     (asm_)(full_)simplify: simpset -> thm -> thm;
   211 
   212 * simplifier.ML no longer part of Pure -- has to be loaded by object
   213 logics (again);
   214 
   215 * added prems argument to simplification procedures;
   216 
   217 * HOL, FOL, ZF: added infix function `addsplits':
   218   instead of `<simpset> setloop (split_tac <thms>)'
   219   you can simply write `<simpset> addsplits <thms>'
   220 
   221 
   222 *** Syntax ***
   223 
   224 * TYPE('a) syntax for type reflection terms;
   225 
   226 * no longer handles consts with name "" -- declare as 'syntax' instead;
   227 
   228 * pretty printer: changed order of mixfix annotation preference (again!);
   229 
   230 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   231 
   232 
   233 *** HOL ***
   234 
   235 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   236   with `addloop' of the simplifier to faciliate case splitting in premises.
   237 
   238 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   239 
   240 * HOL/Auth: new protocol proofs including some for the Internet
   241   protocol TLS;
   242 
   243 * HOL/Map: new theory of `maps' a la VDM;
   244 
   245 * HOL/simplifier: simplification procedures nat_cancel_sums for
   246 cancelling out common nat summands from =, <, <= (in)equalities, or
   247 differences; simplification procedures nat_cancel_factor for
   248 cancelling common factor from =, <, <= (in)equalities over natural
   249 sums; nat_cancel contains both kinds of procedures, it is installed by
   250 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   251 
   252 * HOL/simplifier: terms of the form
   253   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   254   are rewritten to
   255   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   256   and those of the form
   257   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   258   are rewritten to
   259   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   260 
   261 * HOL/datatype
   262   Each datatype `t' now comes with a theorem `split_t_case' of the form
   263 
   264   P(t_case f1 ... fn x) =
   265      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   266         ...
   267        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   268      )
   269 
   270   and a theorem `split_t_case_asm' of the form
   271 
   272   P(t_case f1 ... fn x) =
   273     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   274         ...
   275        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   276      )
   277   which can be added to a simpset via `addsplits'. The existing theorems
   278   expand_list_case and expand_option_case have been renamed to
   279   split_list_case and split_option_case.
   280 
   281 * HOL/Arithmetic:
   282   - `pred n' is automatically converted to `n-1'.
   283     Users are strongly encouraged not to use `pred' any longer,
   284     because it will disappear altogether at some point.
   285   - Users are strongly encouraged to write "0 < n" rather than
   286     "n ~= 0". Theorems and proof tools have been modified towards this
   287     `standard'.
   288 
   289 * HOL/Lists:
   290   the function "set_of_list" has been renamed "set" (and its theorems too);
   291   the function "nth" now takes its arguments in the reverse order and
   292   has acquired the infix notation "!" as in "xs!n".
   293 
   294 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   295 
   296 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   297   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   298 
   299 * HOL/record: extensible records with schematic structural subtyping
   300 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   301 still lacks various theorems and concrete record syntax;
   302 
   303 
   304 *** HOLCF ***
   305 
   306 * removed "axioms" and "generated by" sections;
   307 
   308 * replaced "ops" section by extended "consts" section, which is capable of
   309   handling the continuous function space "->" directly;
   310 
   311 * domain package:
   312   . proves theorems immediately and stores them in the theory,
   313   . creates hierachical name space,
   314   . now uses normal mixfix annotations (instead of cinfix...),
   315   . minor changes to some names and values (for consistency),
   316   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   317   . separator between mutual domain defs: changed "," to "and",
   318   . improved handling of sort constraints;  now they have to
   319     appear on the left-hand side of the equations only;
   320 
   321 * fixed LAM <x,y,zs>.b syntax;
   322 
   323 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   324 adm (%x. P (t x)), where P is chainfinite and t continuous;
   325 
   326 
   327 *** FOL and ZF ***
   328 
   329 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   330   with `addloop' of the simplifier to faciliate case splitting in premises.
   331 
   332 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   333 in HOL, they strip ALL and --> from proved theorems;
   334 
   335 
   336 
   337 New in Isabelle94-8 (May 1997)
   338 ------------------------------
   339 
   340 *** General Changes ***
   341 
   342 * new utilities to build / run / maintain Isabelle etc. (in parts
   343 still somewhat experimental); old Makefiles etc. still functional;
   344 
   345 * new 'Isabelle System Manual';
   346 
   347 * INSTALL text, together with ./configure and ./build scripts;
   348 
   349 * reimplemented type inference for greater efficiency, better error
   350 messages and clean internal interface;
   351 
   352 * prlim command for dealing with lots of subgoals (an easier way of
   353 setting goals_limit);
   354 
   355 
   356 *** Syntax ***
   357 
   358 * supports alternative (named) syntax tables (parser and pretty
   359 printer); internal interface is provided by add_modesyntax(_i);
   360 
   361 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   362 be used in conjunction with the Isabelle symbol font; uses the
   363 "symbols" syntax table;
   364 
   365 * added token_translation interface (may translate name tokens in
   366 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   367 the current print_mode); IMPORTANT: user print translation functions
   368 are responsible for marking newly introduced bounds
   369 (Syntax.mark_boundT);
   370 
   371 * token translations for modes "xterm" and "xterm_color" that display
   372 names in bold, underline etc. or colors (which requires a color
   373 version of xterm);
   374 
   375 * infixes may now be declared with names independent of their syntax;
   376 
   377 * added typed_print_translation (like print_translation, but may
   378 access type of constant);
   379 
   380 
   381 *** Classical Reasoner ***
   382 
   383 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   384 some limitations.  Blast_tac...
   385   + ignores addss, addbefore, addafter; this restriction is intrinsic
   386   + ignores elimination rules that don't have the correct format
   387 	(the conclusion MUST be a formula variable)
   388   + ignores types, which can make HOL proofs fail
   389   + rules must not require higher-order unification, e.g. apply_type in ZF
   390     [message "Function Var's argument not a bound variable" relates to this]
   391   + its proof strategy is more general but can actually be slower
   392 
   393 * substitution with equality assumptions no longer permutes other
   394 assumptions;
   395 
   396 * minor changes in semantics of addafter (now called addaltern); renamed
   397 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   398 (and access functions for it);
   399 
   400 * improved combination of classical reasoner and simplifier: 
   401   + functions for handling clasimpsets
   402   + improvement of addss: now the simplifier is called _after_ the
   403     safe steps.
   404   + safe variant of addss called addSss: uses safe simplifications
   405     _during_ the safe steps. It is more complete as it allows multiple 
   406     instantiations of unknowns (e.g. with slow_tac).
   407 
   408 *** Simplifier ***
   409 
   410 * added interface for simplification procedures (functions that
   411 produce *proven* rewrite rules on the fly, depending on current
   412 redex);
   413 
   414 * ordering on terms as parameter (used for ordered rewriting);
   415 
   416 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   417 
   418 * the solver is now split into a safe and an unsafe part.
   419 This should be invisible for the normal user, except that the
   420 functions setsolver and addsolver have been renamed to setSolver and
   421 addSolver; added safe_asm_full_simp_tac;
   422 
   423 
   424 *** HOL ***
   425 
   426 * a generic induction tactic `induct_tac' which works for all datatypes and
   427 also for type `nat';
   428 
   429 * a generic case distinction tactic `exhaust_tac' which works for all
   430 datatypes and also for type `nat';
   431 
   432 * each datatype comes with a function `size';
   433 
   434 * patterns in case expressions allow tuple patterns as arguments to
   435 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   436 
   437 * primrec now also works with type nat;
   438 
   439 * recdef: a new declaration form, allows general recursive functions to be
   440 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   441 
   442 * the constant for negation has been renamed from "not" to "Not" to
   443 harmonize with FOL, ZF, LK, etc.;
   444 
   445 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   446 infinite lists;
   447 
   448 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   449 
   450 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   451 problems in commutative rings, using axiomatic type classes for + and *;
   452 
   453 * more examples in HOL/MiniML and HOL/Auth;
   454 
   455 * more default rewrite rules for quantifiers, union/intersection;
   456 
   457 * a new constant `arbitrary == @x.False';
   458 
   459 * HOLCF/IOA replaces old HOL/IOA;
   460 
   461 * HOLCF changes: derived all rules and arities 
   462   + axiomatic type classes instead of classes 
   463   + typedef instead of faking type definitions
   464   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   465   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   466   + eliminated the types void, one, tr
   467   + use unit lift and bool lift (with translations) instead of one and tr
   468   + eliminated blift from Lift3.thy (use Def instead of blift)
   469   all eliminated rules are derived as theorems --> no visible changes ;
   470 
   471 
   472 *** ZF ***
   473 
   474 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   475 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   476 as ZF_cs addSIs [equalityI];
   477 
   478 
   479 
   480 New in Isabelle94-7 (November 96)
   481 ---------------------------------
   482 
   483 * allowing negative levels (as offsets) in prlev and choplev;
   484 
   485 * super-linear speedup for large simplifications;
   486 
   487 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   488 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   489 FAIL); can suppress it using the command Delsimps (ex_simps @
   490 all_simps); De Morgan laws are also now included, by default;
   491 
   492 * improved printing of ==>  :  ~:
   493 
   494 * new object-logic "Sequents" adds linear logic, while replacing LK
   495 and Modal (thanks to Sara Kalvala);
   496 
   497 * HOL/Auth: correctness proofs for authentication protocols;
   498 
   499 * HOL: new auto_tac combines rewriting and classical reasoning (many
   500 examples on HOL/Auth);
   501 
   502 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   503 the rewriter and classical reasoner simultaneously;
   504 
   505 * function uresult no longer returns theorems in "standard" format;
   506 regain previous version by: val uresult = standard o uresult;
   507 
   508 
   509 
   510 New in Isabelle94-6
   511 -------------------
   512 
   513 * oracles -- these establish an interface between Isabelle and trusted
   514 external reasoners, which may deliver results as theorems;
   515 
   516 * proof objects (in particular record all uses of oracles);
   517 
   518 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   519 
   520 * "constdefs" section in theory files;
   521 
   522 * "primrec" section (HOL) no longer requires names;
   523 
   524 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   525 
   526 
   527 
   528 New in Isabelle94-5
   529 -------------------
   530 
   531 * reduced space requirements;
   532 
   533 * automatic HTML generation from theories;
   534 
   535 * theory files no longer require "..." (quotes) around most types;
   536 
   537 * new examples, including two proofs of the Church-Rosser theorem;
   538 
   539 * non-curried (1994) version of HOL is no longer distributed;
   540 
   541 
   542 
   543 New in Isabelle94-4
   544 -------------------
   545 
   546 * greatly reduced space requirements;
   547 
   548 * theory files (.thy) no longer require \...\ escapes at line breaks;
   549 
   550 * searchable theorem database (see the section "Retrieving theorems" on 
   551 page 8 of the Reference Manual);
   552 
   553 * new examples, including Grabczewski's monumental case study of the
   554 Axiom of Choice;
   555 
   556 * The previous version of HOL renamed to Old_HOL;
   557 
   558 * The new version of HOL (previously called CHOL) uses a curried syntax 
   559 for functions.  Application looks like f a b instead of f(a,b);
   560 
   561 * Mutually recursive inductive definitions finally work in HOL;
   562 
   563 * In ZF, pattern-matching on tuples is now available in all abstractions and
   564 translates to the operator "split";
   565 
   566 
   567 
   568 New in Isabelle94-3
   569 -------------------
   570 
   571 * new infix operator, addss, allowing the classical reasoner to 
   572 perform simplification at each step of its search.  Example:
   573 	fast_tac (cs addss ss)
   574 
   575 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   576 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   577 look like (a,b) instead of <a,b>;
   578 
   579 * PLEASE NOTE: CHOL will eventually replace HOL!
   580 
   581 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   582 It translates to the operator "split".  A new theory of integers is available;
   583 
   584 * In ZF, integer numerals now denote two's-complement binary integers.
   585 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   586 
   587 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   588 of the Axiom of Choice;
   589 
   590 
   591 
   592 New in Isabelle94-2
   593 -------------------
   594 
   595 * Significantly faster resolution;  
   596 
   597 * the different sections in a .thy file can now be mixed and repeated
   598 freely;
   599 
   600 * Database of theorems for FOL, HOL and ZF.  New
   601 commands including qed, qed_goal and bind_thm store theorems in the database.
   602 
   603 * Simple database queries: return a named theorem (get_thm) or all theorems of
   604 a given theory (thms_of), or find out what theory a theorem was proved in
   605 (theory_of_thm);
   606 
   607 * Bugs fixed in the inductive definition and datatype packages;
   608 
   609 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   610 and HOL_dup_cs obsolete;
   611 
   612 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   613 have been removed;
   614 
   615 * Simpler definition of function space in ZF;
   616 
   617 * new results about cardinal and ordinal arithmetic in ZF;
   618 
   619 * 'subtype' facility in HOL for introducing new types as subsets of existing
   620 types;
   621 
   622 
   623 $Id$