NEWS
author wenzelm
Fri Jul 03 18:53:02 1998 +0200 (1998-07-03)
changeset 5127 ef467e05da61
parent 5125 463a0e9df5b5
child 5128 66c4d554e93f
permissions -rw-r--r--
cleaned up;
     1 
     2 Isabelle NEWS -- history of user-visible changes
     3 ================================================
     4 
     5 New in this Isabelle version
     6 ----------------------------
     7 
     8 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     9 
    10 * HOL/inductive requires Inductive.thy as an ancestor;
    11 
    12 
    13 *** Proof tools ***
    14 
    15 * Simplifier: Asm_full_simp_tac is now more aggressive.
    16   1. It will sometimes reorient premises if that increases their power to
    17      simplify.
    18   2. It does no longer proceed strictly from left to right but may also
    19      rotate premises to achieve further simplification.
    20   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    21   old Asm_full_simp_tac in that it does not rotate premises.
    22 
    23 * Classical reasoner: wrapper mechanism for the classical reasoner now
    24 allows for selected deletion of wrappers, by introduction of names for
    25 wrapper functionals.  This implies that addbefore, addSbefore,
    26 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    27 and that adding two tactics with the same name overwrites the first
    28 one (emitting a warning).
    29   type wrapper = (int -> tactic) -> (int -> tactic)
    30   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    31   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    32   delWrapper, delSWrapper: claset *  string            -> claset
    33   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    34 
    35 * HOL/split_all_tac is now much faster and fails if there is nothing
    36 to split.  Existing (fragile) proofs may require adaption because the
    37 order and the names of the automatically generated variables have
    38 changed.  split_all_tac has moved within claset() from unsafe wrappers
    39 to safe wrappers, which means that !!-bound variables are split much
    40 more aggressively, and safe_tac and clarify_tac now split such
    41 variables.  If this splitting is not appropriate, use delSWrapper
    42 "split_all_tac".
    43 
    44 * HOL/Simplifier:
    45 
    46  - Rewrite rules for case distinctions can now be added permanently to
    47    the default simpset using Addsplits just like Addsimps. They can be
    48    removed via Delsplits just like Delsimps. Lower-case versions are
    49    also available.
    50 
    51  - The rule split_if is now part of the default simpset. This means
    52    that the simplifier will eliminate all occurrences of if-then-else
    53    in the conclusion of a goal. To prevent this, you can either remove
    54    split_if completely from the default simpset by `Delsplits
    55    [split_if]' or remove it in a specific call of the simplifier using
    56    `... delsplits [split_if]'.  You can also add/delete other case
    57    splitting rules to/from the default simpset: every datatype
    58    generates suitable rules `split_t_case' and `split_t_case_asm'
    59    (where t is the name of the datatype).
    60 
    61 * Classical reasoner - Simplifier combination: new force_tac (and
    62 derivatives Force_tac, force) combines rewriting and classical
    63 reasoning (and whatever other tools) similarly to auto_tac, but is
    64 aimed to solve the given subgoal completely;
    65 
    66 
    67 *** General ***
    68 
    69 * new toplevel commands `Goal' and `Goalw' that improve upon `goal'
    70 and `goalw': the theory is no longer needed as an explicit argument -
    71 the current theory context is used; assumptions are no longer returned
    72 at the ML-level unless one of them starts with ==> or !!; it is
    73 recommended to convert to these new commands using isatool fixgoal (as
    74 usual, backup your sources first!);
    75 
    76 * new toplevel commands 'thm' and 'thms' for retrieving theorems from
    77 the current theory context;
    78 
    79 * new theory section 'nonterminals' for purely syntactic types;
    80 
    81 * new theory section 'setup' for generic ML setup functions
    82 (e.g. package initialization);
    83 
    84 
    85 *** HOL ***
    86 
    87 * reorganized the main HOL image: HOL/Integ and String loaded by
    88 default; theory Main includes everything;
    89 
    90 * added option_map_eq_Some to the default simpset claset;
    91 
    92 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
    93 
    94 * many new identities for unions, intersections, set difference, etc.;
    95 
    96 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
    97 called split_if, split_split, split_sum_case and split_nat_case (to go
    98 with add/delsplits);
    99 
   100 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   101 (?x::unit) = (); this is made part of the default simpset, which COULD
   102 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   103 'Delsimprocs [unit_eq_proc];' as last resort);
   104 
   105 * HOL/record package: now includes concrete syntax for record terms
   106 (still lacks important theorems, like surjective pairing and split);
   107 
   108 * HOL/inductive package reorganized and improved: now supports mutual
   109 definitions such as
   110 
   111   inductive EVEN ODD
   112     intrs
   113       null " 0 : EVEN"
   114       oddI "n : EVEN ==> Suc n : ODD"
   115       evenI "n : ODD ==> Suc n : EVEN"
   116 
   117 new component "elims" of the structure created by the package contains
   118 an elimination rule for each of the recursive sets; requires
   119 Inductive.thy as an ancestor; component "mutual_induct" no longer
   120 exists - the induction rule is always contained in "induct"; inductive
   121 definitions now handle disjunctive premises correctly (also ZF);
   122 
   123 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   124 the well-founded relation;
   125 
   126 * HOL/Update: new theory of function updates:
   127     f(a:=b) == %x. if x=a then b else f x
   128 may also be iterated as in f(a:=b,c:=d,...);
   129 
   130 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   131 
   132 * HOL/List: new function list_update written xs[i:=v] that updates the i-th
   133   list position. May also be iterated as in xs[i:=a,j:=b,...].
   134 
   135 * HOL/Arith:
   136   - removed 'pred' (predecessor) function;
   137   - generalized some theorems about n-1;
   138   - many new laws about "div" and "mod";
   139   - new laws about greatest common divisors (see theory ex/Primes);
   140 
   141 * HOL/Relation: renamed the relational operator r^-1 "converse"
   142 instead of "inverse";
   143 
   144 * directory HOL/Real: a construction of the reals using Dedekind cuts
   145 (not included by default);
   146 
   147 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   148 
   149 
   150 *** ZF ***
   151 
   152 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   153 
   154 
   155 *** Internal programming interfaces ***
   156 
   157 * improved the theory data mechanism to support encapsulation (data
   158 kind name replaced by private Object.kind, acting as authorization
   159 key); new type-safe user interface via functor TheoryDataFun;
   160 
   161 * module Pure/Syntax now offers quote / antiquote translation
   162 functions (useful for Hoare logic etc. with implicit dependencies);
   163 
   164 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   165 cterm -> thm;
   166 
   167 
   168 
   169 New in Isabelle98 (January 1998)
   170 --------------------------------
   171 
   172 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   173 
   174 * changed lexical syntax of terms / types: dots made part of long
   175 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   176 
   177 * simpset (and claset) reference variable replaced by functions
   178 simpset / simpset_ref;
   179 
   180 * no longer supports theory aliases (via merge) and non-trivial
   181 implicit merge of thms' signatures;
   182 
   183 * most internal names of constants changed due to qualified names;
   184 
   185 * changed Pure/Sequence interface (see Pure/seq.ML);
   186 
   187 
   188 *** General Changes ***
   189 
   190 * hierachically structured name spaces (for consts, types, axms, thms
   191 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   192 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   193 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   194 long_names for fully qualified output names; NOTE: ML programs
   195 (special tactics, packages etc.) referring to internal names may have
   196 to be adapted to cope with fully qualified names; in case of severe
   197 backward campatibility problems try setting 'global_names' at compile
   198 time to have enrything declared within a flat name space; one may also
   199 fine tune name declarations in theories via the 'global' and 'local'
   200 section;
   201 
   202 * reimplemented the implicit simpset and claset using the new anytype
   203 data filed in signatures; references simpset:simpset ref etc. are
   204 replaced by functions simpset:unit->simpset and
   205 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   206 to patch your ML files accordingly;
   207 
   208 * HTML output now includes theory graph data for display with Java
   209 applet or isatool browser; data generated automatically via isatool
   210 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   211 
   212 * defs may now be conditional; improved rewrite_goals_tac to handle
   213 conditional equations;
   214 
   215 * defs now admits additional type arguments, using TYPE('a) syntax;
   216 
   217 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   218 creates a new theory node; implicit merge of thms' signatures is
   219 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   220 transfer:theory->thm->thm in (rare) cases;
   221 
   222 * improved handling of draft signatures / theories; draft thms (and
   223 ctyps, cterms) are automatically promoted to real ones;
   224 
   225 * slightly changed interfaces for oracles: admit many per theory, named
   226 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   227 
   228 * print_goals: optional output of const types (set show_consts and
   229 show_types);
   230 
   231 * improved output of warnings (###) and errors (***);
   232 
   233 * subgoal_tac displays a warning if the new subgoal has type variables;
   234 
   235 * removed old README and Makefiles;
   236 
   237 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   238 
   239 * removed obsolete init_pps and init_database;
   240 
   241 * deleted the obsolete tactical STATE, which was declared by
   242     fun STATE tacfun st = tacfun st st;
   243 
   244 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   245 (which abbreviates $HOME);
   246 
   247 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   248 use isatool fixseq to adapt your ML programs (this works for fully
   249 qualified references to the Sequence structure only!);
   250 
   251 * use_thy no longer requires writable current directory; it always
   252 reloads .ML *and* .thy file, if either one is out of date;
   253 
   254 
   255 *** Classical Reasoner ***
   256 
   257 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   258 tactics that use classical reasoning to simplify a subgoal without
   259 splitting it into several subgoals;
   260 
   261 * Safe_tac: like safe_tac but uses the default claset;
   262 
   263 
   264 *** Simplifier ***
   265 
   266 * added simplification meta rules:
   267     (asm_)(full_)simplify: simpset -> thm -> thm;
   268 
   269 * simplifier.ML no longer part of Pure -- has to be loaded by object
   270 logics (again);
   271 
   272 * added prems argument to simplification procedures;
   273 
   274 * HOL, FOL, ZF: added infix function `addsplits':
   275   instead of `<simpset> setloop (split_tac <thms>)'
   276   you can simply write `<simpset> addsplits <thms>'
   277 
   278 
   279 *** Syntax ***
   280 
   281 * TYPE('a) syntax for type reflection terms;
   282 
   283 * no longer handles consts with name "" -- declare as 'syntax' instead;
   284 
   285 * pretty printer: changed order of mixfix annotation preference (again!);
   286 
   287 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   288 
   289 
   290 *** HOL ***
   291 
   292 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   293   with `addloop' of the simplifier to faciliate case splitting in premises.
   294 
   295 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   296 
   297 * HOL/Auth: new protocol proofs including some for the Internet
   298   protocol TLS;
   299 
   300 * HOL/Map: new theory of `maps' a la VDM;
   301 
   302 * HOL/simplifier: simplification procedures nat_cancel_sums for
   303 cancelling out common nat summands from =, <, <= (in)equalities, or
   304 differences; simplification procedures nat_cancel_factor for
   305 cancelling common factor from =, <, <= (in)equalities over natural
   306 sums; nat_cancel contains both kinds of procedures, it is installed by
   307 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   308 
   309 * HOL/simplifier: terms of the form
   310   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   311   are rewritten to
   312   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   313   and those of the form
   314   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   315   are rewritten to
   316   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   317 
   318 * HOL/datatype
   319   Each datatype `t' now comes with a theorem `split_t_case' of the form
   320 
   321   P(t_case f1 ... fn x) =
   322      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   323         ...
   324        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   325      )
   326 
   327   and a theorem `split_t_case_asm' of the form
   328 
   329   P(t_case f1 ... fn x) =
   330     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   331         ...
   332        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   333      )
   334   which can be added to a simpset via `addsplits'. The existing theorems
   335   expand_list_case and expand_option_case have been renamed to
   336   split_list_case and split_option_case.
   337 
   338 * HOL/Arithmetic:
   339   - `pred n' is automatically converted to `n-1'.
   340     Users are strongly encouraged not to use `pred' any longer,
   341     because it will disappear altogether at some point.
   342   - Users are strongly encouraged to write "0 < n" rather than
   343     "n ~= 0". Theorems and proof tools have been modified towards this
   344     `standard'.
   345 
   346 * HOL/Lists:
   347   the function "set_of_list" has been renamed "set" (and its theorems too);
   348   the function "nth" now takes its arguments in the reverse order and
   349   has acquired the infix notation "!" as in "xs!n".
   350 
   351 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   352 
   353 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   354   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   355 
   356 * HOL/record: extensible records with schematic structural subtyping
   357 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   358 still lacks various theorems and concrete record syntax;
   359 
   360 
   361 *** HOLCF ***
   362 
   363 * removed "axioms" and "generated by" sections;
   364 
   365 * replaced "ops" section by extended "consts" section, which is capable of
   366   handling the continuous function space "->" directly;
   367 
   368 * domain package:
   369   . proves theorems immediately and stores them in the theory,
   370   . creates hierachical name space,
   371   . now uses normal mixfix annotations (instead of cinfix...),
   372   . minor changes to some names and values (for consistency),
   373   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   374   . separator between mutual domain defs: changed "," to "and",
   375   . improved handling of sort constraints;  now they have to
   376     appear on the left-hand side of the equations only;
   377 
   378 * fixed LAM <x,y,zs>.b syntax;
   379 
   380 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   381 adm (%x. P (t x)), where P is chainfinite and t continuous;
   382 
   383 
   384 *** FOL and ZF ***
   385 
   386 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   387   with `addloop' of the simplifier to faciliate case splitting in premises.
   388 
   389 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   390 in HOL, they strip ALL and --> from proved theorems;
   391 
   392 
   393 
   394 New in Isabelle94-8 (May 1997)
   395 ------------------------------
   396 
   397 *** General Changes ***
   398 
   399 * new utilities to build / run / maintain Isabelle etc. (in parts
   400 still somewhat experimental); old Makefiles etc. still functional;
   401 
   402 * new 'Isabelle System Manual';
   403 
   404 * INSTALL text, together with ./configure and ./build scripts;
   405 
   406 * reimplemented type inference for greater efficiency, better error
   407 messages and clean internal interface;
   408 
   409 * prlim command for dealing with lots of subgoals (an easier way of
   410 setting goals_limit);
   411 
   412 
   413 *** Syntax ***
   414 
   415 * supports alternative (named) syntax tables (parser and pretty
   416 printer); internal interface is provided by add_modesyntax(_i);
   417 
   418 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   419 be used in conjunction with the Isabelle symbol font; uses the
   420 "symbols" syntax table;
   421 
   422 * added token_translation interface (may translate name tokens in
   423 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   424 the current print_mode); IMPORTANT: user print translation functions
   425 are responsible for marking newly introduced bounds
   426 (Syntax.mark_boundT);
   427 
   428 * token translations for modes "xterm" and "xterm_color" that display
   429 names in bold, underline etc. or colors (which requires a color
   430 version of xterm);
   431 
   432 * infixes may now be declared with names independent of their syntax;
   433 
   434 * added typed_print_translation (like print_translation, but may
   435 access type of constant);
   436 
   437 
   438 *** Classical Reasoner ***
   439 
   440 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   441 some limitations.  Blast_tac...
   442   + ignores addss, addbefore, addafter; this restriction is intrinsic
   443   + ignores elimination rules that don't have the correct format
   444 	(the conclusion MUST be a formula variable)
   445   + ignores types, which can make HOL proofs fail
   446   + rules must not require higher-order unification, e.g. apply_type in ZF
   447     [message "Function Var's argument not a bound variable" relates to this]
   448   + its proof strategy is more general but can actually be slower
   449 
   450 * substitution with equality assumptions no longer permutes other
   451 assumptions;
   452 
   453 * minor changes in semantics of addafter (now called addaltern); renamed
   454 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   455 (and access functions for it);
   456 
   457 * improved combination of classical reasoner and simplifier: 
   458   + functions for handling clasimpsets
   459   + improvement of addss: now the simplifier is called _after_ the
   460     safe steps.
   461   + safe variant of addss called addSss: uses safe simplifications
   462     _during_ the safe steps. It is more complete as it allows multiple 
   463     instantiations of unknowns (e.g. with slow_tac).
   464 
   465 *** Simplifier ***
   466 
   467 * added interface for simplification procedures (functions that
   468 produce *proven* rewrite rules on the fly, depending on current
   469 redex);
   470 
   471 * ordering on terms as parameter (used for ordered rewriting);
   472 
   473 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   474 
   475 * the solver is now split into a safe and an unsafe part.
   476 This should be invisible for the normal user, except that the
   477 functions setsolver and addsolver have been renamed to setSolver and
   478 addSolver; added safe_asm_full_simp_tac;
   479 
   480 
   481 *** HOL ***
   482 
   483 * a generic induction tactic `induct_tac' which works for all datatypes and
   484 also for type `nat';
   485 
   486 * a generic case distinction tactic `exhaust_tac' which works for all
   487 datatypes and also for type `nat';
   488 
   489 * each datatype comes with a function `size';
   490 
   491 * patterns in case expressions allow tuple patterns as arguments to
   492 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   493 
   494 * primrec now also works with type nat;
   495 
   496 * recdef: a new declaration form, allows general recursive functions to be
   497 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   498 
   499 * the constant for negation has been renamed from "not" to "Not" to
   500 harmonize with FOL, ZF, LK, etc.;
   501 
   502 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   503 infinite lists;
   504 
   505 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   506 
   507 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   508 problems in commutative rings, using axiomatic type classes for + and *;
   509 
   510 * more examples in HOL/MiniML and HOL/Auth;
   511 
   512 * more default rewrite rules for quantifiers, union/intersection;
   513 
   514 * a new constant `arbitrary == @x.False';
   515 
   516 * HOLCF/IOA replaces old HOL/IOA;
   517 
   518 * HOLCF changes: derived all rules and arities 
   519   + axiomatic type classes instead of classes 
   520   + typedef instead of faking type definitions
   521   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   522   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   523   + eliminated the types void, one, tr
   524   + use unit lift and bool lift (with translations) instead of one and tr
   525   + eliminated blift from Lift3.thy (use Def instead of blift)
   526   all eliminated rules are derived as theorems --> no visible changes ;
   527 
   528 
   529 *** ZF ***
   530 
   531 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   532 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   533 as ZF_cs addSIs [equalityI];
   534 
   535 
   536 
   537 New in Isabelle94-7 (November 96)
   538 ---------------------------------
   539 
   540 * allowing negative levels (as offsets) in prlev and choplev;
   541 
   542 * super-linear speedup for large simplifications;
   543 
   544 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   545 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   546 FAIL); can suppress it using the command Delsimps (ex_simps @
   547 all_simps); De Morgan laws are also now included, by default;
   548 
   549 * improved printing of ==>  :  ~:
   550 
   551 * new object-logic "Sequents" adds linear logic, while replacing LK
   552 and Modal (thanks to Sara Kalvala);
   553 
   554 * HOL/Auth: correctness proofs for authentication protocols;
   555 
   556 * HOL: new auto_tac combines rewriting and classical reasoning (many
   557 examples on HOL/Auth);
   558 
   559 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   560 the rewriter and classical reasoner simultaneously;
   561 
   562 * function uresult no longer returns theorems in "standard" format;
   563 regain previous version by: val uresult = standard o uresult;
   564 
   565 
   566 
   567 New in Isabelle94-6
   568 -------------------
   569 
   570 * oracles -- these establish an interface between Isabelle and trusted
   571 external reasoners, which may deliver results as theorems;
   572 
   573 * proof objects (in particular record all uses of oracles);
   574 
   575 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   576 
   577 * "constdefs" section in theory files;
   578 
   579 * "primrec" section (HOL) no longer requires names;
   580 
   581 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   582 
   583 
   584 
   585 New in Isabelle94-5
   586 -------------------
   587 
   588 * reduced space requirements;
   589 
   590 * automatic HTML generation from theories;
   591 
   592 * theory files no longer require "..." (quotes) around most types;
   593 
   594 * new examples, including two proofs of the Church-Rosser theorem;
   595 
   596 * non-curried (1994) version of HOL is no longer distributed;
   597 
   598 
   599 
   600 New in Isabelle94-4
   601 -------------------
   602 
   603 * greatly reduced space requirements;
   604 
   605 * theory files (.thy) no longer require \...\ escapes at line breaks;
   606 
   607 * searchable theorem database (see the section "Retrieving theorems" on 
   608 page 8 of the Reference Manual);
   609 
   610 * new examples, including Grabczewski's monumental case study of the
   611 Axiom of Choice;
   612 
   613 * The previous version of HOL renamed to Old_HOL;
   614 
   615 * The new version of HOL (previously called CHOL) uses a curried syntax 
   616 for functions.  Application looks like f a b instead of f(a,b);
   617 
   618 * Mutually recursive inductive definitions finally work in HOL;
   619 
   620 * In ZF, pattern-matching on tuples is now available in all abstractions and
   621 translates to the operator "split";
   622 
   623 
   624 
   625 New in Isabelle94-3
   626 -------------------
   627 
   628 * new infix operator, addss, allowing the classical reasoner to 
   629 perform simplification at each step of its search.  Example:
   630 	fast_tac (cs addss ss)
   631 
   632 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   633 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   634 look like (a,b) instead of <a,b>;
   635 
   636 * PLEASE NOTE: CHOL will eventually replace HOL!
   637 
   638 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   639 It translates to the operator "split".  A new theory of integers is available;
   640 
   641 * In ZF, integer numerals now denote two's-complement binary integers.
   642 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   643 
   644 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   645 of the Axiom of Choice;
   646 
   647 
   648 
   649 New in Isabelle94-2
   650 -------------------
   651 
   652 * Significantly faster resolution;  
   653 
   654 * the different sections in a .thy file can now be mixed and repeated
   655 freely;
   656 
   657 * Database of theorems for FOL, HOL and ZF.  New
   658 commands including qed, qed_goal and bind_thm store theorems in the database.
   659 
   660 * Simple database queries: return a named theorem (get_thm) or all theorems of
   661 a given theory (thms_of), or find out what theory a theorem was proved in
   662 (theory_of_thm);
   663 
   664 * Bugs fixed in the inductive definition and datatype packages;
   665 
   666 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   667 and HOL_dup_cs obsolete;
   668 
   669 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   670 have been removed;
   671 
   672 * Simpler definition of function space in ZF;
   673 
   674 * new results about cardinal and ordinal arithmetic in ZF;
   675 
   676 * 'subtype' facility in HOL for introducing new types as subsets of existing
   677 types;
   678 
   679 
   680 $Id$