NEWS
author wenzelm
Fri Jun 05 14:40:07 1998 +0200 (1998-06-05)
changeset 5002 7b4c2a153738
parent 4981 9703ba0e9122
child 5008 6f56d9650ee9
permissions -rw-r--r--
* improved the theory data mechanism to support real encapsulation;
main change of the internal interfaces: data kind name (string)
replaced by private Object.kind, acting as authorization key;
     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 
   108 *** ZF ***
   109 
   110 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   111 
   112 
   113 *** Internal changes ***
   114 
   115 * improved the theory data mechanism to support real encapsulation;
   116 main change of the internal interfaces: data kind name (string)
   117 replaced by private Object.kind, acting as authorization key;
   118 
   119 
   120 
   121 New in Isabelle98 (January 1998)
   122 --------------------------------
   123 
   124 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   125 
   126 * changed lexical syntax of terms / types: dots made part of long
   127 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   128 
   129 * simpset (and claset) reference variable replaced by functions
   130 simpset / simpset_ref;
   131 
   132 * no longer supports theory aliases (via merge) and non-trivial
   133 implicit merge of thms' signatures;
   134 
   135 * most internal names of constants changed due to qualified names;
   136 
   137 * changed Pure/Sequence interface (see Pure/seq.ML);
   138 
   139 
   140 *** General Changes ***
   141 
   142 * hierachically structured name spaces (for consts, types, axms, thms
   143 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   144 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   145 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   146 long_names for fully qualified output names; NOTE: ML programs
   147 (special tactics, packages etc.) referring to internal names may have
   148 to be adapted to cope with fully qualified names; in case of severe
   149 backward campatibility problems try setting 'global_names' at compile
   150 time to have enrything declared within a flat name space; one may also
   151 fine tune name declarations in theories via the 'global' and 'local'
   152 section;
   153 
   154 * reimplemented the implicit simpset and claset using the new anytype
   155 data filed in signatures; references simpset:simpset ref etc. are
   156 replaced by functions simpset:unit->simpset and
   157 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   158 to patch your ML files accordingly;
   159 
   160 * HTML output now includes theory graph data for display with Java
   161 applet or isatool browser; data generated automatically via isatool
   162 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   163 
   164 * defs may now be conditional; improved rewrite_goals_tac to handle
   165 conditional equations;
   166 
   167 * defs now admits additional type arguments, using TYPE('a) syntax;
   168 
   169 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   170 creates a new theory node; implicit merge of thms' signatures is
   171 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   172 transfer:theory->thm->thm in (rare) cases;
   173 
   174 * improved handling of draft signatures / theories; draft thms (and
   175 ctyps, cterms) are automatically promoted to real ones;
   176 
   177 * slightly changed interfaces for oracles: admit many per theory, named
   178 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   179 
   180 * print_goals: optional output of const types (set show_consts and
   181 show_types);
   182 
   183 * improved output of warnings (###) and errors (***);
   184 
   185 * subgoal_tac displays a warning if the new subgoal has type variables;
   186 
   187 * removed old README and Makefiles;
   188 
   189 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   190 
   191 * removed obsolete init_pps and init_database;
   192 
   193 * deleted the obsolete tactical STATE, which was declared by
   194     fun STATE tacfun st = tacfun st st;
   195 
   196 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   197 (which abbreviates $HOME);
   198 
   199 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   200 use isatool fixseq to adapt your ML programs (this works for fully
   201 qualified references to the Sequence structure only!);
   202 
   203 * use_thy no longer requires writable current directory; it always
   204 reloads .ML *and* .thy file, if either one is out of date;
   205 
   206 
   207 *** Classical Reasoner ***
   208 
   209 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   210 tactics that use classical reasoning to simplify a subgoal without
   211 splitting it into several subgoals;
   212 
   213 * Safe_tac: like safe_tac but uses the default claset;
   214 
   215 
   216 *** Simplifier ***
   217 
   218 * added simplification meta rules:
   219     (asm_)(full_)simplify: simpset -> thm -> thm;
   220 
   221 * simplifier.ML no longer part of Pure -- has to be loaded by object
   222 logics (again);
   223 
   224 * added prems argument to simplification procedures;
   225 
   226 * HOL, FOL, ZF: added infix function `addsplits':
   227   instead of `<simpset> setloop (split_tac <thms>)'
   228   you can simply write `<simpset> addsplits <thms>'
   229 
   230 
   231 *** Syntax ***
   232 
   233 * TYPE('a) syntax for type reflection terms;
   234 
   235 * no longer handles consts with name "" -- declare as 'syntax' instead;
   236 
   237 * pretty printer: changed order of mixfix annotation preference (again!);
   238 
   239 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   240 
   241 
   242 *** HOL ***
   243 
   244 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   245   with `addloop' of the simplifier to faciliate case splitting in premises.
   246 
   247 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   248 
   249 * HOL/Auth: new protocol proofs including some for the Internet
   250   protocol TLS;
   251 
   252 * HOL/Map: new theory of `maps' a la VDM;
   253 
   254 * HOL/simplifier: simplification procedures nat_cancel_sums for
   255 cancelling out common nat summands from =, <, <= (in)equalities, or
   256 differences; simplification procedures nat_cancel_factor for
   257 cancelling common factor from =, <, <= (in)equalities over natural
   258 sums; nat_cancel contains both kinds of procedures, it is installed by
   259 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   260 
   261 * HOL/simplifier: terms of the form
   262   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   263   are rewritten to
   264   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   265   and those of the form
   266   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   267   are rewritten to
   268   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   269 
   270 * HOL/datatype
   271   Each datatype `t' now comes with a theorem `split_t_case' of the form
   272 
   273   P(t_case f1 ... fn x) =
   274      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   275         ...
   276        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   277      )
   278 
   279   and a theorem `split_t_case_asm' of the form
   280 
   281   P(t_case f1 ... fn x) =
   282     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   283         ...
   284        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   285      )
   286   which can be added to a simpset via `addsplits'. The existing theorems
   287   expand_list_case and expand_option_case have been renamed to
   288   split_list_case and split_option_case.
   289 
   290 * HOL/Arithmetic:
   291   - `pred n' is automatically converted to `n-1'.
   292     Users are strongly encouraged not to use `pred' any longer,
   293     because it will disappear altogether at some point.
   294   - Users are strongly encouraged to write "0 < n" rather than
   295     "n ~= 0". Theorems and proof tools have been modified towards this
   296     `standard'.
   297 
   298 * HOL/Lists:
   299   the function "set_of_list" has been renamed "set" (and its theorems too);
   300   the function "nth" now takes its arguments in the reverse order and
   301   has acquired the infix notation "!" as in "xs!n".
   302 
   303 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   304 
   305 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   306   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   307 
   308 * HOL/record: extensible records with schematic structural subtyping
   309 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   310 still lacks various theorems and concrete record syntax;
   311 
   312 
   313 *** HOLCF ***
   314 
   315 * removed "axioms" and "generated by" sections;
   316 
   317 * replaced "ops" section by extended "consts" section, which is capable of
   318   handling the continuous function space "->" directly;
   319 
   320 * domain package:
   321   . proves theorems immediately and stores them in the theory,
   322   . creates hierachical name space,
   323   . now uses normal mixfix annotations (instead of cinfix...),
   324   . minor changes to some names and values (for consistency),
   325   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   326   . separator between mutual domain defs: changed "," to "and",
   327   . improved handling of sort constraints;  now they have to
   328     appear on the left-hand side of the equations only;
   329 
   330 * fixed LAM <x,y,zs>.b syntax;
   331 
   332 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   333 adm (%x. P (t x)), where P is chainfinite and t continuous;
   334 
   335 
   336 *** FOL and ZF ***
   337 
   338 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   339   with `addloop' of the simplifier to faciliate case splitting in premises.
   340 
   341 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   342 in HOL, they strip ALL and --> from proved theorems;
   343 
   344 
   345 
   346 New in Isabelle94-8 (May 1997)
   347 ------------------------------
   348 
   349 *** General Changes ***
   350 
   351 * new utilities to build / run / maintain Isabelle etc. (in parts
   352 still somewhat experimental); old Makefiles etc. still functional;
   353 
   354 * new 'Isabelle System Manual';
   355 
   356 * INSTALL text, together with ./configure and ./build scripts;
   357 
   358 * reimplemented type inference for greater efficiency, better error
   359 messages and clean internal interface;
   360 
   361 * prlim command for dealing with lots of subgoals (an easier way of
   362 setting goals_limit);
   363 
   364 
   365 *** Syntax ***
   366 
   367 * supports alternative (named) syntax tables (parser and pretty
   368 printer); internal interface is provided by add_modesyntax(_i);
   369 
   370 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   371 be used in conjunction with the Isabelle symbol font; uses the
   372 "symbols" syntax table;
   373 
   374 * added token_translation interface (may translate name tokens in
   375 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   376 the current print_mode); IMPORTANT: user print translation functions
   377 are responsible for marking newly introduced bounds
   378 (Syntax.mark_boundT);
   379 
   380 * token translations for modes "xterm" and "xterm_color" that display
   381 names in bold, underline etc. or colors (which requires a color
   382 version of xterm);
   383 
   384 * infixes may now be declared with names independent of their syntax;
   385 
   386 * added typed_print_translation (like print_translation, but may
   387 access type of constant);
   388 
   389 
   390 *** Classical Reasoner ***
   391 
   392 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   393 some limitations.  Blast_tac...
   394   + ignores addss, addbefore, addafter; this restriction is intrinsic
   395   + ignores elimination rules that don't have the correct format
   396 	(the conclusion MUST be a formula variable)
   397   + ignores types, which can make HOL proofs fail
   398   + rules must not require higher-order unification, e.g. apply_type in ZF
   399     [message "Function Var's argument not a bound variable" relates to this]
   400   + its proof strategy is more general but can actually be slower
   401 
   402 * substitution with equality assumptions no longer permutes other
   403 assumptions;
   404 
   405 * minor changes in semantics of addafter (now called addaltern); renamed
   406 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   407 (and access functions for it);
   408 
   409 * improved combination of classical reasoner and simplifier: 
   410   + functions for handling clasimpsets
   411   + improvement of addss: now the simplifier is called _after_ the
   412     safe steps.
   413   + safe variant of addss called addSss: uses safe simplifications
   414     _during_ the safe steps. It is more complete as it allows multiple 
   415     instantiations of unknowns (e.g. with slow_tac).
   416 
   417 *** Simplifier ***
   418 
   419 * added interface for simplification procedures (functions that
   420 produce *proven* rewrite rules on the fly, depending on current
   421 redex);
   422 
   423 * ordering on terms as parameter (used for ordered rewriting);
   424 
   425 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   426 
   427 * the solver is now split into a safe and an unsafe part.
   428 This should be invisible for the normal user, except that the
   429 functions setsolver and addsolver have been renamed to setSolver and
   430 addSolver; added safe_asm_full_simp_tac;
   431 
   432 
   433 *** HOL ***
   434 
   435 * a generic induction tactic `induct_tac' which works for all datatypes and
   436 also for type `nat';
   437 
   438 * a generic case distinction tactic `exhaust_tac' which works for all
   439 datatypes and also for type `nat';
   440 
   441 * each datatype comes with a function `size';
   442 
   443 * patterns in case expressions allow tuple patterns as arguments to
   444 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   445 
   446 * primrec now also works with type nat;
   447 
   448 * recdef: a new declaration form, allows general recursive functions to be
   449 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   450 
   451 * the constant for negation has been renamed from "not" to "Not" to
   452 harmonize with FOL, ZF, LK, etc.;
   453 
   454 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   455 infinite lists;
   456 
   457 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   458 
   459 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   460 problems in commutative rings, using axiomatic type classes for + and *;
   461 
   462 * more examples in HOL/MiniML and HOL/Auth;
   463 
   464 * more default rewrite rules for quantifiers, union/intersection;
   465 
   466 * a new constant `arbitrary == @x.False';
   467 
   468 * HOLCF/IOA replaces old HOL/IOA;
   469 
   470 * HOLCF changes: derived all rules and arities 
   471   + axiomatic type classes instead of classes 
   472   + typedef instead of faking type definitions
   473   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   474   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   475   + eliminated the types void, one, tr
   476   + use unit lift and bool lift (with translations) instead of one and tr
   477   + eliminated blift from Lift3.thy (use Def instead of blift)
   478   all eliminated rules are derived as theorems --> no visible changes ;
   479 
   480 
   481 *** ZF ***
   482 
   483 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   484 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   485 as ZF_cs addSIs [equalityI];
   486 
   487 
   488 
   489 New in Isabelle94-7 (November 96)
   490 ---------------------------------
   491 
   492 * allowing negative levels (as offsets) in prlev and choplev;
   493 
   494 * super-linear speedup for large simplifications;
   495 
   496 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   497 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   498 FAIL); can suppress it using the command Delsimps (ex_simps @
   499 all_simps); De Morgan laws are also now included, by default;
   500 
   501 * improved printing of ==>  :  ~:
   502 
   503 * new object-logic "Sequents" adds linear logic, while replacing LK
   504 and Modal (thanks to Sara Kalvala);
   505 
   506 * HOL/Auth: correctness proofs for authentication protocols;
   507 
   508 * HOL: new auto_tac combines rewriting and classical reasoning (many
   509 examples on HOL/Auth);
   510 
   511 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   512 the rewriter and classical reasoner simultaneously;
   513 
   514 * function uresult no longer returns theorems in "standard" format;
   515 regain previous version by: val uresult = standard o uresult;
   516 
   517 
   518 
   519 New in Isabelle94-6
   520 -------------------
   521 
   522 * oracles -- these establish an interface between Isabelle and trusted
   523 external reasoners, which may deliver results as theorems;
   524 
   525 * proof objects (in particular record all uses of oracles);
   526 
   527 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   528 
   529 * "constdefs" section in theory files;
   530 
   531 * "primrec" section (HOL) no longer requires names;
   532 
   533 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   534 
   535 
   536 
   537 New in Isabelle94-5
   538 -------------------
   539 
   540 * reduced space requirements;
   541 
   542 * automatic HTML generation from theories;
   543 
   544 * theory files no longer require "..." (quotes) around most types;
   545 
   546 * new examples, including two proofs of the Church-Rosser theorem;
   547 
   548 * non-curried (1994) version of HOL is no longer distributed;
   549 
   550 
   551 
   552 New in Isabelle94-4
   553 -------------------
   554 
   555 * greatly reduced space requirements;
   556 
   557 * theory files (.thy) no longer require \...\ escapes at line breaks;
   558 
   559 * searchable theorem database (see the section "Retrieving theorems" on 
   560 page 8 of the Reference Manual);
   561 
   562 * new examples, including Grabczewski's monumental case study of the
   563 Axiom of Choice;
   564 
   565 * The previous version of HOL renamed to Old_HOL;
   566 
   567 * The new version of HOL (previously called CHOL) uses a curried syntax 
   568 for functions.  Application looks like f a b instead of f(a,b);
   569 
   570 * Mutually recursive inductive definitions finally work in HOL;
   571 
   572 * In ZF, pattern-matching on tuples is now available in all abstractions and
   573 translates to the operator "split";
   574 
   575 
   576 
   577 New in Isabelle94-3
   578 -------------------
   579 
   580 * new infix operator, addss, allowing the classical reasoner to 
   581 perform simplification at each step of its search.  Example:
   582 	fast_tac (cs addss ss)
   583 
   584 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   585 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   586 look like (a,b) instead of <a,b>;
   587 
   588 * PLEASE NOTE: CHOL will eventually replace HOL!
   589 
   590 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   591 It translates to the operator "split".  A new theory of integers is available;
   592 
   593 * In ZF, integer numerals now denote two's-complement binary integers.
   594 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   595 
   596 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   597 of the Axiom of Choice;
   598 
   599 
   600 
   601 New in Isabelle94-2
   602 -------------------
   603 
   604 * Significantly faster resolution;  
   605 
   606 * the different sections in a .thy file can now be mixed and repeated
   607 freely;
   608 
   609 * Database of theorems for FOL, HOL and ZF.  New
   610 commands including qed, qed_goal and bind_thm store theorems in the database.
   611 
   612 * Simple database queries: return a named theorem (get_thm) or all theorems of
   613 a given theory (thms_of), or find out what theory a theorem was proved in
   614 (theory_of_thm);
   615 
   616 * Bugs fixed in the inductive definition and datatype packages;
   617 
   618 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   619 and HOL_dup_cs obsolete;
   620 
   621 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   622 have been removed;
   623 
   624 * Simpler definition of function space in ZF;
   625 
   626 * new results about cardinal and ordinal arithmetic in ZF;
   627 
   628 * 'subtype' facility in HOL for introducing new types as subsets of existing
   629 types;
   630 
   631 
   632 $Id$