NEWS
author wenzelm
Fri Jul 03 17:36:45 1998 +0200 (1998-07-03)
changeset 5125 463a0e9df5b5
parent 5109 b3d18eb3ac20
child 5127 ef467e05da61
permissions -rw-r--r--
reorganized the main HOL image;
     1 Isabelle NEWS -- history of user-visible changes
     2 ================================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** General Changes ***
     8 
     9 * new toplevel commands `Goal' and `Goalw' that improve upon `goal'
    10 and `goalw': the theory is no longer needed as an explicit argument -
    11 the current theory is used; assumptions are no longer returned at the
    12 ML-level unless one of them starts with ==> or !!; it is recommended
    13 to convert to these new commands using isatool fixgoal (as usual,
    14 backup your sources first!);
    15 
    16 * Simplifier: Asm_full_simp_tac is now more aggressive.
    17   1. It will sometimes reorient premises if that increases their power to
    18      simplify.
    19   2. It does no longer proceed strictly from left to right but may also
    20      rotate premises to achieve further simplification.
    21   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    22   old Asm_full_simp_tac in that it does not rotate premises.
    23 
    24 * Changed wrapper mechanism for the classical reasoner now allows for
    25 selected deletion of wrappers, by introduction of names for wrapper
    26 functionals.  This implies that addbefore, addSbefore, addaltern, and
    27 addSaltern now take a pair (name, tactic) as argument, and that adding
    28 two tactics with the same name overwrites the first one (emitting a
    29 warning).
    30   type wrapper = (int -> tactic) -> (int -> tactic)
    31   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    32   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    33   delWrapper, delSWrapper: claset *  string            -> claset
    34   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    35 
    36 * inductive definitions now handle disjunctive premises correctly (HOL
    37 and ZF);
    38 
    39 * new toplevel commands 'thm' and 'thms' for retrieving theorems from
    40 the current theory context;
    41 
    42 * new theory section 'nonterminals';
    43 
    44 * new theory section 'setup';
    45 
    46 
    47 *** HOL ***
    48 
    49 * reorganized the main HOL image: HOL/Integ and String loaded by
    50 default; theory Main includes everything;
    51 
    52 * HOL/Real: a construction of the reals using Dedekind cuts;
    53 
    54 * HOL/record: now includes concrete syntax for record terms (still
    55 lacks important theorems, like surjective pairing and split);
    56 
    57 * Inductive definition package: Mutually recursive definitions such as
    58 
    59   inductive EVEN ODD
    60     intrs
    61       null " 0 : EVEN"
    62       oddI "n : EVEN ==> Suc n : ODD"
    63       evenI "n : ODD ==> Suc n : EVEN"
    64 
    65   are now possible. Theories containing (co)inductive definitions must now
    66   have theory "Inductive" as an ancestor. The new component "elims" of the
    67   structure created by the package contains an elimination rule for each of
    68   the recursive sets. Note that the component "mutual_induct" no longer
    69   exists - the induction rule is always contained in "induct".
    70 
    71 * simplification procedure unit_eq_proc rewrites (?x::unit) = (); this
    72 is made part of the default simpset of Prod.thy, which COULD MAKE
    73 EXISTING PROOFS FAIL (consider 'Delsimprocs [unit_eq_proc];' as last
    74 resort);
    75 
    76 * new force_tac (and its derivations Force_tac, force): combines
    77 rewriting and classical reasoning (and whatever other tools) similarly
    78 to auto_tac, but is aimed to solve the given subgoal totally;
    79 
    80 * added option_map_eq_Some to simpset() and claset();
    81 
    82 * New directory HOL/UNITY: Chandy and Misra's UNITY formalism;
    83 
    84 * New theory HOL/Update of function updates:
    85   f(a:=b) == %x. if x=a then b else f x
    86   May also be iterated as in f(a:=b,c:=d,...).
    87 
    88 * HOL/List: new function list_update written xs[i:=v] that updates the i-th
    89   list position. May also be iterated as in xs[i:=a,j:=b,...].
    90 
    91 * split_all_tac is now much faster and fails if there is nothing to
    92 split.  Existing (fragile) proofs may require adaption because the
    93 order and the names of the automatically generated variables have
    94 changed.  split_all_tac has moved within claset() from usafe wrappers
    95 to safe wrappers, which means that !!-bound variables are splitted
    96 much more aggressively, and safe_tac and clarify_tac now split such
    97 variables.  If this splitting is not appropriate, use delSWrapper
    98 "split_all_tac".
    99 
   100 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   101 
   102 * HOL/Arithmetic:
   103   
   104   - removed 'pred' (predecessor) function
   105   - generalized some theorems about n-1
   106   - Many new laws about "div" and "mod"
   107   - New laws about greatest common divisors (see theory ex/Primes)
   108 
   109 * HOL/Relation: renamed the relational operatotr r^-1 "converse"
   110 instead of "inverse";
   111 
   112 * recdef can now declare non-recursive functions, with {} supplied as
   113 the well-founded relation;
   114 
   115 * expand_if, expand_split, expand_sum_case and expand_nat_case are now called
   116   split_if, split_split, split_sum_case and split_nat_case
   117   (to go with add/delsplits).
   118 
   119 * Simplifier:
   120 
   121  -Rewrite rules for case distinctions can now be added permanently to the
   122   default simpset using Addsplits just like Addsimps. They can be removed via
   123   Delsplits just like Delsimps. Lower-case versions are also available.
   124 
   125  -The rule split_if is now part of the default simpset. This means that
   126   the simplifier will eliminate all ocurrences of if-then-else in the
   127   conclusion of a goal. To prevent this, you can either remove split_if
   128   completely from the default simpset by `Delsplits [split_if]' or
   129   remove it in a specific call of the simplifier using
   130   `... delsplits [split_if]'.
   131   You can also add/delete other case splitting rules to/from the default
   132   simpset: every datatype generates suitable rules `split_t_case' and
   133   `split_t_case_asm' (where t is the name of the datatype).
   134 
   135 * new theory Vimage (inverse image of a function, syntax f-``B);
   136 
   137 * many new identities for unions, intersections, set difference, etc.;
   138 
   139 
   140 *** ZF ***
   141 
   142 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   143 
   144 
   145 *** Internal changes ***
   146 
   147 * improved the theory data mechanism to support encapsulation (data
   148 kind name replaced by private Object.kind, acting as authorization
   149 key); new type-safe user interface via functor TheoryDataFun;
   150 
   151 * module Pure/Syntax now offers quote / antiquote translation
   152 functions (useful for Hoare logic etc. with implicit dependencies);
   153 
   154 
   155 
   156 New in Isabelle98 (January 1998)
   157 --------------------------------
   158 
   159 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   160 
   161 * changed lexical syntax of terms / types: dots made part of long
   162 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   163 
   164 * simpset (and claset) reference variable replaced by functions
   165 simpset / simpset_ref;
   166 
   167 * no longer supports theory aliases (via merge) and non-trivial
   168 implicit merge of thms' signatures;
   169 
   170 * most internal names of constants changed due to qualified names;
   171 
   172 * changed Pure/Sequence interface (see Pure/seq.ML);
   173 
   174 
   175 *** General Changes ***
   176 
   177 * hierachically structured name spaces (for consts, types, axms, thms
   178 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   179 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   180 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   181 long_names for fully qualified output names; NOTE: ML programs
   182 (special tactics, packages etc.) referring to internal names may have
   183 to be adapted to cope with fully qualified names; in case of severe
   184 backward campatibility problems try setting 'global_names' at compile
   185 time to have enrything declared within a flat name space; one may also
   186 fine tune name declarations in theories via the 'global' and 'local'
   187 section;
   188 
   189 * reimplemented the implicit simpset and claset using the new anytype
   190 data filed in signatures; references simpset:simpset ref etc. are
   191 replaced by functions simpset:unit->simpset and
   192 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   193 to patch your ML files accordingly;
   194 
   195 * HTML output now includes theory graph data for display with Java
   196 applet or isatool browser; data generated automatically via isatool
   197 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   198 
   199 * defs may now be conditional; improved rewrite_goals_tac to handle
   200 conditional equations;
   201 
   202 * defs now admits additional type arguments, using TYPE('a) syntax;
   203 
   204 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   205 creates a new theory node; implicit merge of thms' signatures is
   206 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   207 transfer:theory->thm->thm in (rare) cases;
   208 
   209 * improved handling of draft signatures / theories; draft thms (and
   210 ctyps, cterms) are automatically promoted to real ones;
   211 
   212 * slightly changed interfaces for oracles: admit many per theory, named
   213 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   214 
   215 * print_goals: optional output of const types (set show_consts and
   216 show_types);
   217 
   218 * improved output of warnings (###) and errors (***);
   219 
   220 * subgoal_tac displays a warning if the new subgoal has type variables;
   221 
   222 * removed old README and Makefiles;
   223 
   224 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   225 
   226 * removed obsolete init_pps and init_database;
   227 
   228 * deleted the obsolete tactical STATE, which was declared by
   229     fun STATE tacfun st = tacfun st st;
   230 
   231 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   232 (which abbreviates $HOME);
   233 
   234 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   235 use isatool fixseq to adapt your ML programs (this works for fully
   236 qualified references to the Sequence structure only!);
   237 
   238 * use_thy no longer requires writable current directory; it always
   239 reloads .ML *and* .thy file, if either one is out of date;
   240 
   241 
   242 *** Classical Reasoner ***
   243 
   244 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   245 tactics that use classical reasoning to simplify a subgoal without
   246 splitting it into several subgoals;
   247 
   248 * Safe_tac: like safe_tac but uses the default claset;
   249 
   250 
   251 *** Simplifier ***
   252 
   253 * added simplification meta rules:
   254     (asm_)(full_)simplify: simpset -> thm -> thm;
   255 
   256 * simplifier.ML no longer part of Pure -- has to be loaded by object
   257 logics (again);
   258 
   259 * added prems argument to simplification procedures;
   260 
   261 * HOL, FOL, ZF: added infix function `addsplits':
   262   instead of `<simpset> setloop (split_tac <thms>)'
   263   you can simply write `<simpset> addsplits <thms>'
   264 
   265 
   266 *** Syntax ***
   267 
   268 * TYPE('a) syntax for type reflection terms;
   269 
   270 * no longer handles consts with name "" -- declare as 'syntax' instead;
   271 
   272 * pretty printer: changed order of mixfix annotation preference (again!);
   273 
   274 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   275 
   276 
   277 *** HOL ***
   278 
   279 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   280   with `addloop' of the simplifier to faciliate case splitting in premises.
   281 
   282 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   283 
   284 * HOL/Auth: new protocol proofs including some for the Internet
   285   protocol TLS;
   286 
   287 * HOL/Map: new theory of `maps' a la VDM;
   288 
   289 * HOL/simplifier: simplification procedures nat_cancel_sums for
   290 cancelling out common nat summands from =, <, <= (in)equalities, or
   291 differences; simplification procedures nat_cancel_factor for
   292 cancelling common factor from =, <, <= (in)equalities over natural
   293 sums; nat_cancel contains both kinds of procedures, it is installed by
   294 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   295 
   296 * HOL/simplifier: terms of the form
   297   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   298   are rewritten to
   299   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   300   and those of the form
   301   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   302   are rewritten to
   303   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   304 
   305 * HOL/datatype
   306   Each datatype `t' now comes with a theorem `split_t_case' of the form
   307 
   308   P(t_case f1 ... fn x) =
   309      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   310         ...
   311        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   312      )
   313 
   314   and a theorem `split_t_case_asm' of the form
   315 
   316   P(t_case f1 ... fn x) =
   317     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   318         ...
   319        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   320      )
   321   which can be added to a simpset via `addsplits'. The existing theorems
   322   expand_list_case and expand_option_case have been renamed to
   323   split_list_case and split_option_case.
   324 
   325 * HOL/Arithmetic:
   326   - `pred n' is automatically converted to `n-1'.
   327     Users are strongly encouraged not to use `pred' any longer,
   328     because it will disappear altogether at some point.
   329   - Users are strongly encouraged to write "0 < n" rather than
   330     "n ~= 0". Theorems and proof tools have been modified towards this
   331     `standard'.
   332 
   333 * HOL/Lists:
   334   the function "set_of_list" has been renamed "set" (and its theorems too);
   335   the function "nth" now takes its arguments in the reverse order and
   336   has acquired the infix notation "!" as in "xs!n".
   337 
   338 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   339 
   340 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   341   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   342 
   343 * HOL/record: extensible records with schematic structural subtyping
   344 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   345 still lacks various theorems and concrete record syntax;
   346 
   347 
   348 *** HOLCF ***
   349 
   350 * removed "axioms" and "generated by" sections;
   351 
   352 * replaced "ops" section by extended "consts" section, which is capable of
   353   handling the continuous function space "->" directly;
   354 
   355 * domain package:
   356   . proves theorems immediately and stores them in the theory,
   357   . creates hierachical name space,
   358   . now uses normal mixfix annotations (instead of cinfix...),
   359   . minor changes to some names and values (for consistency),
   360   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   361   . separator between mutual domain defs: changed "," to "and",
   362   . improved handling of sort constraints;  now they have to
   363     appear on the left-hand side of the equations only;
   364 
   365 * fixed LAM <x,y,zs>.b syntax;
   366 
   367 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   368 adm (%x. P (t x)), where P is chainfinite and t continuous;
   369 
   370 
   371 *** FOL and ZF ***
   372 
   373 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   374   with `addloop' of the simplifier to faciliate case splitting in premises.
   375 
   376 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   377 in HOL, they strip ALL and --> from proved theorems;
   378 
   379 
   380 
   381 New in Isabelle94-8 (May 1997)
   382 ------------------------------
   383 
   384 *** General Changes ***
   385 
   386 * new utilities to build / run / maintain Isabelle etc. (in parts
   387 still somewhat experimental); old Makefiles etc. still functional;
   388 
   389 * new 'Isabelle System Manual';
   390 
   391 * INSTALL text, together with ./configure and ./build scripts;
   392 
   393 * reimplemented type inference for greater efficiency, better error
   394 messages and clean internal interface;
   395 
   396 * prlim command for dealing with lots of subgoals (an easier way of
   397 setting goals_limit);
   398 
   399 
   400 *** Syntax ***
   401 
   402 * supports alternative (named) syntax tables (parser and pretty
   403 printer); internal interface is provided by add_modesyntax(_i);
   404 
   405 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   406 be used in conjunction with the Isabelle symbol font; uses the
   407 "symbols" syntax table;
   408 
   409 * added token_translation interface (may translate name tokens in
   410 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   411 the current print_mode); IMPORTANT: user print translation functions
   412 are responsible for marking newly introduced bounds
   413 (Syntax.mark_boundT);
   414 
   415 * token translations for modes "xterm" and "xterm_color" that display
   416 names in bold, underline etc. or colors (which requires a color
   417 version of xterm);
   418 
   419 * infixes may now be declared with names independent of their syntax;
   420 
   421 * added typed_print_translation (like print_translation, but may
   422 access type of constant);
   423 
   424 
   425 *** Classical Reasoner ***
   426 
   427 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   428 some limitations.  Blast_tac...
   429   + ignores addss, addbefore, addafter; this restriction is intrinsic
   430   + ignores elimination rules that don't have the correct format
   431 	(the conclusion MUST be a formula variable)
   432   + ignores types, which can make HOL proofs fail
   433   + rules must not require higher-order unification, e.g. apply_type in ZF
   434     [message "Function Var's argument not a bound variable" relates to this]
   435   + its proof strategy is more general but can actually be slower
   436 
   437 * substitution with equality assumptions no longer permutes other
   438 assumptions;
   439 
   440 * minor changes in semantics of addafter (now called addaltern); renamed
   441 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   442 (and access functions for it);
   443 
   444 * improved combination of classical reasoner and simplifier: 
   445   + functions for handling clasimpsets
   446   + improvement of addss: now the simplifier is called _after_ the
   447     safe steps.
   448   + safe variant of addss called addSss: uses safe simplifications
   449     _during_ the safe steps. It is more complete as it allows multiple 
   450     instantiations of unknowns (e.g. with slow_tac).
   451 
   452 *** Simplifier ***
   453 
   454 * added interface for simplification procedures (functions that
   455 produce *proven* rewrite rules on the fly, depending on current
   456 redex);
   457 
   458 * ordering on terms as parameter (used for ordered rewriting);
   459 
   460 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   461 
   462 * the solver is now split into a safe and an unsafe part.
   463 This should be invisible for the normal user, except that the
   464 functions setsolver and addsolver have been renamed to setSolver and
   465 addSolver; added safe_asm_full_simp_tac;
   466 
   467 
   468 *** HOL ***
   469 
   470 * a generic induction tactic `induct_tac' which works for all datatypes and
   471 also for type `nat';
   472 
   473 * a generic case distinction tactic `exhaust_tac' which works for all
   474 datatypes and also for type `nat';
   475 
   476 * each datatype comes with a function `size';
   477 
   478 * patterns in case expressions allow tuple patterns as arguments to
   479 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   480 
   481 * primrec now also works with type nat;
   482 
   483 * recdef: a new declaration form, allows general recursive functions to be
   484 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   485 
   486 * the constant for negation has been renamed from "not" to "Not" to
   487 harmonize with FOL, ZF, LK, etc.;
   488 
   489 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   490 infinite lists;
   491 
   492 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   493 
   494 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   495 problems in commutative rings, using axiomatic type classes for + and *;
   496 
   497 * more examples in HOL/MiniML and HOL/Auth;
   498 
   499 * more default rewrite rules for quantifiers, union/intersection;
   500 
   501 * a new constant `arbitrary == @x.False';
   502 
   503 * HOLCF/IOA replaces old HOL/IOA;
   504 
   505 * HOLCF changes: derived all rules and arities 
   506   + axiomatic type classes instead of classes 
   507   + typedef instead of faking type definitions
   508   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   509   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   510   + eliminated the types void, one, tr
   511   + use unit lift and bool lift (with translations) instead of one and tr
   512   + eliminated blift from Lift3.thy (use Def instead of blift)
   513   all eliminated rules are derived as theorems --> no visible changes ;
   514 
   515 
   516 *** ZF ***
   517 
   518 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   519 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   520 as ZF_cs addSIs [equalityI];
   521 
   522 
   523 
   524 New in Isabelle94-7 (November 96)
   525 ---------------------------------
   526 
   527 * allowing negative levels (as offsets) in prlev and choplev;
   528 
   529 * super-linear speedup for large simplifications;
   530 
   531 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   532 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   533 FAIL); can suppress it using the command Delsimps (ex_simps @
   534 all_simps); De Morgan laws are also now included, by default;
   535 
   536 * improved printing of ==>  :  ~:
   537 
   538 * new object-logic "Sequents" adds linear logic, while replacing LK
   539 and Modal (thanks to Sara Kalvala);
   540 
   541 * HOL/Auth: correctness proofs for authentication protocols;
   542 
   543 * HOL: new auto_tac combines rewriting and classical reasoning (many
   544 examples on HOL/Auth);
   545 
   546 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   547 the rewriter and classical reasoner simultaneously;
   548 
   549 * function uresult no longer returns theorems in "standard" format;
   550 regain previous version by: val uresult = standard o uresult;
   551 
   552 
   553 
   554 New in Isabelle94-6
   555 -------------------
   556 
   557 * oracles -- these establish an interface between Isabelle and trusted
   558 external reasoners, which may deliver results as theorems;
   559 
   560 * proof objects (in particular record all uses of oracles);
   561 
   562 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   563 
   564 * "constdefs" section in theory files;
   565 
   566 * "primrec" section (HOL) no longer requires names;
   567 
   568 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   569 
   570 
   571 
   572 New in Isabelle94-5
   573 -------------------
   574 
   575 * reduced space requirements;
   576 
   577 * automatic HTML generation from theories;
   578 
   579 * theory files no longer require "..." (quotes) around most types;
   580 
   581 * new examples, including two proofs of the Church-Rosser theorem;
   582 
   583 * non-curried (1994) version of HOL is no longer distributed;
   584 
   585 
   586 
   587 New in Isabelle94-4
   588 -------------------
   589 
   590 * greatly reduced space requirements;
   591 
   592 * theory files (.thy) no longer require \...\ escapes at line breaks;
   593 
   594 * searchable theorem database (see the section "Retrieving theorems" on 
   595 page 8 of the Reference Manual);
   596 
   597 * new examples, including Grabczewski's monumental case study of the
   598 Axiom of Choice;
   599 
   600 * The previous version of HOL renamed to Old_HOL;
   601 
   602 * The new version of HOL (previously called CHOL) uses a curried syntax 
   603 for functions.  Application looks like f a b instead of f(a,b);
   604 
   605 * Mutually recursive inductive definitions finally work in HOL;
   606 
   607 * In ZF, pattern-matching on tuples is now available in all abstractions and
   608 translates to the operator "split";
   609 
   610 
   611 
   612 New in Isabelle94-3
   613 -------------------
   614 
   615 * new infix operator, addss, allowing the classical reasoner to 
   616 perform simplification at each step of its search.  Example:
   617 	fast_tac (cs addss ss)
   618 
   619 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   620 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   621 look like (a,b) instead of <a,b>;
   622 
   623 * PLEASE NOTE: CHOL will eventually replace HOL!
   624 
   625 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   626 It translates to the operator "split".  A new theory of integers is available;
   627 
   628 * In ZF, integer numerals now denote two's-complement binary integers.
   629 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   630 
   631 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   632 of the Axiom of Choice;
   633 
   634 
   635 
   636 New in Isabelle94-2
   637 -------------------
   638 
   639 * Significantly faster resolution;  
   640 
   641 * the different sections in a .thy file can now be mixed and repeated
   642 freely;
   643 
   644 * Database of theorems for FOL, HOL and ZF.  New
   645 commands including qed, qed_goal and bind_thm store theorems in the database.
   646 
   647 * Simple database queries: return a named theorem (get_thm) or all theorems of
   648 a given theory (thms_of), or find out what theory a theorem was proved in
   649 (theory_of_thm);
   650 
   651 * Bugs fixed in the inductive definition and datatype packages;
   652 
   653 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   654 and HOL_dup_cs obsolete;
   655 
   656 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   657 have been removed;
   658 
   659 * Simpler definition of function space in ZF;
   660 
   661 * new results about cardinal and ordinal arithmetic in ZF;
   662 
   663 * 'subtype' facility in HOL for introducing new types as subsets of existing
   664 types;
   665 
   666 
   667 $Id$