NEWS
author berghofe
Thu Jul 30 15:52:33 1998 +0200 (1998-07-30)
changeset 5214 75c6392d1274
parent 5207 dd4f51adfff3
child 5217 3ecd7c952396
permissions -rw-r--r--
Adapted to new datatype package.
     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 * several changes of proof tools (see next section);
    11 
    12 * HOL/datatype:
    13   - Theories using datatypes must now have Datatype.thy as an
    14     ancestor.
    15   - The specific <typename>.induct_tac no longer exists - use the
    16     generic induct_tac instead.
    17   - natE has been renamed to nat.exhaustion - use exhaust_tac
    18     instead of res_inst_tac ... natE. Note that the variable
    19     names in nat.exhaustion differ from the names in natE, this
    20     may cause some "fragile" proofs to fail.
    21   - the theorems split_<typename>_case and split_<typename>_case_asm
    22     have been renamed to <typename>.split and <typename>.split_asm.
    23   - Since default sorts are no longer ignored by the package,
    24     some datatype definitions may have to be annotated with
    25     explicit sort constraints.
    26   - Primrec definitions no longer require function name and type
    27     of recursive argument.
    28   Use isatool fixdatatype to adapt your theories and proof scripts
    29   to the new package (as usual, backup your sources first!).
    30 
    31 * HOL/inductive requires Inductive.thy as an ancestor; `inj_onto' is
    32 now called `inj_on' (which makes more sense);
    33 
    34 * HOL/Relation: renamed the relational operator r^-1 to 'converse'
    35 from 'inverse' (for compatibility with ZF and some literature);
    36 
    37 
    38 *** Proof tools ***
    39 
    40 * Simplifier: Asm_full_simp_tac is now more aggressive.
    41   1. It will sometimes reorient premises if that increases their power to
    42      simplify.
    43   2. It does no longer proceed strictly from left to right but may also
    44      rotate premises to achieve further simplification.
    45   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    46   old Asm_full_simp_tac in that it does not rotate premises.
    47 
    48 * Classical reasoner: wrapper mechanism for the classical reasoner now
    49 allows for selected deletion of wrappers, by introduction of names for
    50 wrapper functionals.  This implies that addbefore, addSbefore,
    51 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    52 and that adding two tactics with the same name overwrites the first
    53 one (emitting a warning).
    54   type wrapper = (int -> tactic) -> (int -> tactic)
    55   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    56   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    57   delWrapper, delSWrapper: claset *  string            -> claset
    58   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    59 
    60 * HOL/split_all_tac is now much faster and fails if there is nothing
    61 to split.  Existing (fragile) proofs may require adaption because the
    62 order and the names of the automatically generated variables have
    63 changed.  split_all_tac has moved within claset() from unsafe wrappers
    64 to safe wrappers, which means that !!-bound variables are split much
    65 more aggressively, and safe_tac and clarify_tac now split such
    66 variables.  If this splitting is not appropriate, use delSWrapper
    67 "split_all_tac".
    68 
    69 * HOL/Simplifier:
    70 
    71  - Rewrite rules for case distinctions can now be added permanently to
    72    the default simpset using Addsplits just like Addsimps. They can be
    73    removed via Delsplits just like Delsimps. Lower-case versions are
    74    also available.
    75 
    76  - The rule split_if is now part of the default simpset. This means
    77    that the simplifier will eliminate all occurrences of if-then-else
    78    in the conclusion of a goal. To prevent this, you can either remove
    79    split_if completely from the default simpset by `Delsplits
    80    [split_if]' or remove it in a specific call of the simplifier using
    81    `... delsplits [split_if]'.  You can also add/delete other case
    82    splitting rules to/from the default simpset: every datatype
    83    generates suitable rules `split_t_case' and `split_t_case_asm'
    84    (where t is the name of the datatype).
    85 
    86 * Classical reasoner - Simplifier combination: new force_tac (and
    87 derivatives Force_tac, force) combines rewriting and classical
    88 reasoning (and whatever other tools) similarly to auto_tac, but is
    89 aimed to solve the given subgoal completely;
    90 
    91 
    92 *** General ***
    93 
    94 * new toplevel commands `Goal' and `Goalw' that improve upon `goal'
    95 and `goalw': the theory is no longer needed as an explicit argument -
    96 the current theory context is used; assumptions are no longer returned
    97 at the ML-level unless one of them starts with ==> or !!; it is
    98 recommended to convert to these new commands using isatool fixgoal (as
    99 usual, backup your sources first!);
   100 
   101 * new toplevel commands 'thm' and 'thms' for retrieving theorems from
   102 the current theory context, and 'theory' to lookup stored theories;
   103 
   104 * new theory section 'nonterminals' for purely syntactic types;
   105 
   106 * new theory section 'setup' for generic ML setup functions
   107 (e.g. package initialization);
   108 
   109 * the distribution now includes Isabelle icons: see
   110 lib/logo/isabelle-{small,tiny}.xpm;
   111 
   112 
   113 *** HOL ***
   114 
   115 * HOL/datatype package reorganized and improved: now supports mutually
   116   recursive datatypes such as
   117 
   118     datatype
   119       'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   120               | SUM ('a aexp) ('a aexp)
   121               | DIFF ('a aexp) ('a aexp)
   122               | NUM 'a
   123     and
   124       'a bexp = LESS ('a aexp) ('a aexp)
   125               | AND ('a bexp) ('a bexp)
   126               | OR ('a bexp) ('a bexp)
   127 
   128   as well as indirectly recursive datatypes such as
   129 
   130     datatype
   131       ('a, 'b) term = Var 'a
   132                     | App 'b ((('a, 'b) term) list)
   133 
   134   The new tactic
   135 
   136     mutual_induct_tac [<var_1>, ..., <var_n>] i
   137 
   138   performs induction on mutually / indirectly recursive datatypes.
   139   Primrec equations are now stored in theory and can be accessed
   140   via <function_name>.simps
   141 
   142 * reorganized the main HOL image: HOL/Integ and String loaded by
   143 default; theory Main includes everything;
   144 
   145 * added option_map_eq_Some to the default simpset claset;
   146 
   147 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   148 
   149 * many new identities for unions, intersections, set difference, etc.;
   150 
   151 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   152 called split_if, split_split, split_sum_case and split_nat_case (to go
   153 with add/delsplits);
   154 
   155 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   156 (?x::unit) = (); this is made part of the default simpset, which COULD
   157 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   158 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   159 unit_abs_eta_conv is added in order to counter the effect of
   160 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   161 %u.f();
   162 
   163 * HOL/record package: now includes concrete syntax for record types,
   164 terms, updates; still lacks important theorems, like surjective
   165 pairing and split;
   166 
   167 * HOL/inductive package reorganized and improved: now supports mutual
   168 definitions such as
   169 
   170   inductive EVEN ODD
   171     intrs
   172       null "0 : EVEN"
   173       oddI "n : EVEN ==> Suc n : ODD"
   174       evenI "n : ODD ==> Suc n : EVEN"
   175 
   176 new component "elims" of the structure created by the package contains
   177 an elimination rule for each of the recursive sets; requires
   178 Inductive.thy as an ancestor; component "mutual_induct" no longer
   179 exists - the induction rule is always contained in "induct"; inductive
   180 definitions now handle disjunctive premises correctly (also ZF);
   181 
   182 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   183 the well-founded relation;
   184 
   185 * HOL/Update: new theory of function updates:
   186     f(a:=b) == %x. if x=a then b else f x
   187 may also be iterated as in f(a:=b,c:=d,...);
   188 
   189 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   190 
   191 * HOL/List: new function list_update written xs[i:=v] that updates the i-th
   192   list position. May also be iterated as in xs[i:=a,j:=b,...].
   193 
   194 * HOL/Arith:
   195   - removed 'pred' (predecessor) function;
   196   - generalized some theorems about n-1;
   197   - many new laws about "div" and "mod";
   198   - new laws about greatest common divisors (see theory ex/Primes);
   199 
   200 * HOL/Relation: renamed the relational operator r^-1 "converse"
   201 instead of "inverse";
   202 
   203 * HOL/Set: added the predicate "disjoint A B" that stands for "A <= Compl B".
   204   This is much better than "A Int B = {}" for Fast/Blast_tac.
   205 
   206 * directory HOL/Real: a construction of the reals using Dedekind cuts
   207 (not included by default);
   208 
   209 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   210 
   211 * calling (stac rew i) now fails if "rew" has no effect on the goal
   212   [previously, this check worked only if the rewrite rule was unconditional]
   213 
   214 
   215 *** ZF ***
   216 
   217 * theory Main includes everything;
   218 
   219 * ZF/Update: new theory of function updates
   220     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   221   may also be iterated as in f(a:=b,c:=d,...);
   222 
   223 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   224 
   225 * calling (stac rew i) now fails if "rew" has no effect on the goal
   226   [previously, this check worked only if the rewrite rule was unconditional]
   227 
   228 * case_tac provided for compatibility with HOL
   229     (like the old excluded_middle_tac, but with subgoals swapped)
   230 
   231 
   232 *** Internal programming interfaces ***
   233 
   234 * removed global_names compatibility flag -- all theory declarations
   235 are qualified by default;
   236 
   237 * improved the theory data mechanism to support encapsulation (data
   238 kind name replaced by private Object.kind, acting as authorization
   239 key); new type-safe user interface via functor TheoryDataFun;
   240 
   241 * module Pure/Syntax now offers quote / antiquote translation
   242 functions (useful for Hoare logic etc. with implicit dependencies);
   243 
   244 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   245 cterm -> thm;
   246 
   247 * Pure: several new basic modules made available for general use, see
   248 also src/Pure/README;
   249 
   250 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   251 subgoal;
   252 
   253 
   254 
   255 New in Isabelle98 (January 1998)
   256 --------------------------------
   257 
   258 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   259 
   260 * changed lexical syntax of terms / types: dots made part of long
   261 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   262 
   263 * simpset (and claset) reference variable replaced by functions
   264 simpset / simpset_ref;
   265 
   266 * no longer supports theory aliases (via merge) and non-trivial
   267 implicit merge of thms' signatures;
   268 
   269 * most internal names of constants changed due to qualified names;
   270 
   271 * changed Pure/Sequence interface (see Pure/seq.ML);
   272 
   273 
   274 *** General Changes ***
   275 
   276 * hierachically structured name spaces (for consts, types, axms, thms
   277 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   278 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   279 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   280 long_names for fully qualified output names; NOTE: ML programs
   281 (special tactics, packages etc.) referring to internal names may have
   282 to be adapted to cope with fully qualified names; in case of severe
   283 backward campatibility problems try setting 'global_names' at compile
   284 time to have enrything declared within a flat name space; one may also
   285 fine tune name declarations in theories via the 'global' and 'local'
   286 section;
   287 
   288 * reimplemented the implicit simpset and claset using the new anytype
   289 data filed in signatures; references simpset:simpset ref etc. are
   290 replaced by functions simpset:unit->simpset and
   291 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   292 to patch your ML files accordingly;
   293 
   294 * HTML output now includes theory graph data for display with Java
   295 applet or isatool browser; data generated automatically via isatool
   296 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   297 
   298 * defs may now be conditional; improved rewrite_goals_tac to handle
   299 conditional equations;
   300 
   301 * defs now admits additional type arguments, using TYPE('a) syntax;
   302 
   303 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   304 creates a new theory node; implicit merge of thms' signatures is
   305 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   306 transfer:theory->thm->thm in (rare) cases;
   307 
   308 * improved handling of draft signatures / theories; draft thms (and
   309 ctyps, cterms) are automatically promoted to real ones;
   310 
   311 * slightly changed interfaces for oracles: admit many per theory, named
   312 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   313 
   314 * print_goals: optional output of const types (set show_consts and
   315 show_types);
   316 
   317 * improved output of warnings (###) and errors (***);
   318 
   319 * subgoal_tac displays a warning if the new subgoal has type variables;
   320 
   321 * removed old README and Makefiles;
   322 
   323 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   324 
   325 * removed obsolete init_pps and init_database;
   326 
   327 * deleted the obsolete tactical STATE, which was declared by
   328     fun STATE tacfun st = tacfun st st;
   329 
   330 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   331 (which abbreviates $HOME);
   332 
   333 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   334 use isatool fixseq to adapt your ML programs (this works for fully
   335 qualified references to the Sequence structure only!);
   336 
   337 * use_thy no longer requires writable current directory; it always
   338 reloads .ML *and* .thy file, if either one is out of date;
   339 
   340 
   341 *** Classical Reasoner ***
   342 
   343 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   344 tactics that use classical reasoning to simplify a subgoal without
   345 splitting it into several subgoals;
   346 
   347 * Safe_tac: like safe_tac but uses the default claset;
   348 
   349 
   350 *** Simplifier ***
   351 
   352 * added simplification meta rules:
   353     (asm_)(full_)simplify: simpset -> thm -> thm;
   354 
   355 * simplifier.ML no longer part of Pure -- has to be loaded by object
   356 logics (again);
   357 
   358 * added prems argument to simplification procedures;
   359 
   360 * HOL, FOL, ZF: added infix function `addsplits':
   361   instead of `<simpset> setloop (split_tac <thms>)'
   362   you can simply write `<simpset> addsplits <thms>'
   363 
   364 
   365 *** Syntax ***
   366 
   367 * TYPE('a) syntax for type reflection terms;
   368 
   369 * no longer handles consts with name "" -- declare as 'syntax' instead;
   370 
   371 * pretty printer: changed order of mixfix annotation preference (again!);
   372 
   373 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   374 
   375 
   376 *** HOL ***
   377 
   378 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   379   with `addloop' of the simplifier to faciliate case splitting in premises.
   380 
   381 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   382 
   383 * HOL/Auth: new protocol proofs including some for the Internet
   384   protocol TLS;
   385 
   386 * HOL/Map: new theory of `maps' a la VDM;
   387 
   388 * HOL/simplifier: simplification procedures nat_cancel_sums for
   389 cancelling out common nat summands from =, <, <= (in)equalities, or
   390 differences; simplification procedures nat_cancel_factor for
   391 cancelling common factor from =, <, <= (in)equalities over natural
   392 sums; nat_cancel contains both kinds of procedures, it is installed by
   393 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   394 
   395 * HOL/simplifier: terms of the form
   396   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   397   are rewritten to
   398   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   399   and those of the form
   400   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   401   are rewritten to
   402   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   403 
   404 * HOL/datatype
   405   Each datatype `t' now comes with a theorem `split_t_case' of the form
   406 
   407   P(t_case f1 ... fn x) =
   408      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   409         ...
   410        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   411      )
   412 
   413   and a theorem `split_t_case_asm' of the form
   414 
   415   P(t_case f1 ... fn x) =
   416     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   417         ...
   418        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   419      )
   420   which can be added to a simpset via `addsplits'. The existing theorems
   421   expand_list_case and expand_option_case have been renamed to
   422   split_list_case and split_option_case.
   423 
   424 * HOL/Arithmetic:
   425   - `pred n' is automatically converted to `n-1'.
   426     Users are strongly encouraged not to use `pred' any longer,
   427     because it will disappear altogether at some point.
   428   - Users are strongly encouraged to write "0 < n" rather than
   429     "n ~= 0". Theorems and proof tools have been modified towards this
   430     `standard'.
   431 
   432 * HOL/Lists:
   433   the function "set_of_list" has been renamed "set" (and its theorems too);
   434   the function "nth" now takes its arguments in the reverse order and
   435   has acquired the infix notation "!" as in "xs!n".
   436 
   437 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   438 
   439 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   440   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   441 
   442 * HOL/record: extensible records with schematic structural subtyping
   443 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   444 still lacks various theorems and concrete record syntax;
   445 
   446 
   447 *** HOLCF ***
   448 
   449 * removed "axioms" and "generated by" sections;
   450 
   451 * replaced "ops" section by extended "consts" section, which is capable of
   452   handling the continuous function space "->" directly;
   453 
   454 * domain package:
   455   . proves theorems immediately and stores them in the theory,
   456   . creates hierachical name space,
   457   . now uses normal mixfix annotations (instead of cinfix...),
   458   . minor changes to some names and values (for consistency),
   459   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   460   . separator between mutual domain defs: changed "," to "and",
   461   . improved handling of sort constraints;  now they have to
   462     appear on the left-hand side of the equations only;
   463 
   464 * fixed LAM <x,y,zs>.b syntax;
   465 
   466 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   467 adm (%x. P (t x)), where P is chainfinite and t continuous;
   468 
   469 
   470 *** FOL and ZF ***
   471 
   472 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   473   with `addloop' of the simplifier to faciliate case splitting in premises.
   474 
   475 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   476 in HOL, they strip ALL and --> from proved theorems;
   477 
   478 
   479 
   480 New in Isabelle94-8 (May 1997)
   481 ------------------------------
   482 
   483 *** General Changes ***
   484 
   485 * new utilities to build / run / maintain Isabelle etc. (in parts
   486 still somewhat experimental); old Makefiles etc. still functional;
   487 
   488 * new 'Isabelle System Manual';
   489 
   490 * INSTALL text, together with ./configure and ./build scripts;
   491 
   492 * reimplemented type inference for greater efficiency, better error
   493 messages and clean internal interface;
   494 
   495 * prlim command for dealing with lots of subgoals (an easier way of
   496 setting goals_limit);
   497 
   498 
   499 *** Syntax ***
   500 
   501 * supports alternative (named) syntax tables (parser and pretty
   502 printer); internal interface is provided by add_modesyntax(_i);
   503 
   504 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   505 be used in conjunction with the Isabelle symbol font; uses the
   506 "symbols" syntax table;
   507 
   508 * added token_translation interface (may translate name tokens in
   509 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   510 the current print_mode); IMPORTANT: user print translation functions
   511 are responsible for marking newly introduced bounds
   512 (Syntax.mark_boundT);
   513 
   514 * token translations for modes "xterm" and "xterm_color" that display
   515 names in bold, underline etc. or colors (which requires a color
   516 version of xterm);
   517 
   518 * infixes may now be declared with names independent of their syntax;
   519 
   520 * added typed_print_translation (like print_translation, but may
   521 access type of constant);
   522 
   523 
   524 *** Classical Reasoner ***
   525 
   526 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   527 some limitations.  Blast_tac...
   528   + ignores addss, addbefore, addafter; this restriction is intrinsic
   529   + ignores elimination rules that don't have the correct format
   530 	(the conclusion MUST be a formula variable)
   531   + ignores types, which can make HOL proofs fail
   532   + rules must not require higher-order unification, e.g. apply_type in ZF
   533     [message "Function Var's argument not a bound variable" relates to this]
   534   + its proof strategy is more general but can actually be slower
   535 
   536 * substitution with equality assumptions no longer permutes other
   537 assumptions;
   538 
   539 * minor changes in semantics of addafter (now called addaltern); renamed
   540 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   541 (and access functions for it);
   542 
   543 * improved combination of classical reasoner and simplifier: 
   544   + functions for handling clasimpsets
   545   + improvement of addss: now the simplifier is called _after_ the
   546     safe steps.
   547   + safe variant of addss called addSss: uses safe simplifications
   548     _during_ the safe steps. It is more complete as it allows multiple 
   549     instantiations of unknowns (e.g. with slow_tac).
   550 
   551 *** Simplifier ***
   552 
   553 * added interface for simplification procedures (functions that
   554 produce *proven* rewrite rules on the fly, depending on current
   555 redex);
   556 
   557 * ordering on terms as parameter (used for ordered rewriting);
   558 
   559 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   560 
   561 * the solver is now split into a safe and an unsafe part.
   562 This should be invisible for the normal user, except that the
   563 functions setsolver and addsolver have been renamed to setSolver and
   564 addSolver; added safe_asm_full_simp_tac;
   565 
   566 
   567 *** HOL ***
   568 
   569 * a generic induction tactic `induct_tac' which works for all datatypes and
   570 also for type `nat';
   571 
   572 * a generic case distinction tactic `exhaust_tac' which works for all
   573 datatypes and also for type `nat';
   574 
   575 * each datatype comes with a function `size';
   576 
   577 * patterns in case expressions allow tuple patterns as arguments to
   578 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   579 
   580 * primrec now also works with type nat;
   581 
   582 * recdef: a new declaration form, allows general recursive functions to be
   583 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   584 
   585 * the constant for negation has been renamed from "not" to "Not" to
   586 harmonize with FOL, ZF, LK, etc.;
   587 
   588 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   589 infinite lists;
   590 
   591 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   592 
   593 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   594 problems in commutative rings, using axiomatic type classes for + and *;
   595 
   596 * more examples in HOL/MiniML and HOL/Auth;
   597 
   598 * more default rewrite rules for quantifiers, union/intersection;
   599 
   600 * a new constant `arbitrary == @x.False';
   601 
   602 * HOLCF/IOA replaces old HOL/IOA;
   603 
   604 * HOLCF changes: derived all rules and arities 
   605   + axiomatic type classes instead of classes 
   606   + typedef instead of faking type definitions
   607   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   608   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   609   + eliminated the types void, one, tr
   610   + use unit lift and bool lift (with translations) instead of one and tr
   611   + eliminated blift from Lift3.thy (use Def instead of blift)
   612   all eliminated rules are derived as theorems --> no visible changes ;
   613 
   614 
   615 *** ZF ***
   616 
   617 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   618 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   619 as ZF_cs addSIs [equalityI];
   620 
   621 
   622 
   623 New in Isabelle94-7 (November 96)
   624 ---------------------------------
   625 
   626 * allowing negative levels (as offsets) in prlev and choplev;
   627 
   628 * super-linear speedup for large simplifications;
   629 
   630 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   631 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   632 FAIL); can suppress it using the command Delsimps (ex_simps @
   633 all_simps); De Morgan laws are also now included, by default;
   634 
   635 * improved printing of ==>  :  ~:
   636 
   637 * new object-logic "Sequents" adds linear logic, while replacing LK
   638 and Modal (thanks to Sara Kalvala);
   639 
   640 * HOL/Auth: correctness proofs for authentication protocols;
   641 
   642 * HOL: new auto_tac combines rewriting and classical reasoning (many
   643 examples on HOL/Auth);
   644 
   645 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   646 the rewriter and classical reasoner simultaneously;
   647 
   648 * function uresult no longer returns theorems in "standard" format;
   649 regain previous version by: val uresult = standard o uresult;
   650 
   651 
   652 
   653 New in Isabelle94-6
   654 -------------------
   655 
   656 * oracles -- these establish an interface between Isabelle and trusted
   657 external reasoners, which may deliver results as theorems;
   658 
   659 * proof objects (in particular record all uses of oracles);
   660 
   661 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   662 
   663 * "constdefs" section in theory files;
   664 
   665 * "primrec" section (HOL) no longer requires names;
   666 
   667 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   668 
   669 
   670 
   671 New in Isabelle94-5
   672 -------------------
   673 
   674 * reduced space requirements;
   675 
   676 * automatic HTML generation from theories;
   677 
   678 * theory files no longer require "..." (quotes) around most types;
   679 
   680 * new examples, including two proofs of the Church-Rosser theorem;
   681 
   682 * non-curried (1994) version of HOL is no longer distributed;
   683 
   684 
   685 
   686 New in Isabelle94-4
   687 -------------------
   688 
   689 * greatly reduced space requirements;
   690 
   691 * theory files (.thy) no longer require \...\ escapes at line breaks;
   692 
   693 * searchable theorem database (see the section "Retrieving theorems" on 
   694 page 8 of the Reference Manual);
   695 
   696 * new examples, including Grabczewski's monumental case study of the
   697 Axiom of Choice;
   698 
   699 * The previous version of HOL renamed to Old_HOL;
   700 
   701 * The new version of HOL (previously called CHOL) uses a curried syntax 
   702 for functions.  Application looks like f a b instead of f(a,b);
   703 
   704 * Mutually recursive inductive definitions finally work in HOL;
   705 
   706 * In ZF, pattern-matching on tuples is now available in all abstractions and
   707 translates to the operator "split";
   708 
   709 
   710 
   711 New in Isabelle94-3
   712 -------------------
   713 
   714 * new infix operator, addss, allowing the classical reasoner to 
   715 perform simplification at each step of its search.  Example:
   716 	fast_tac (cs addss ss)
   717 
   718 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   719 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   720 look like (a,b) instead of <a,b>;
   721 
   722 * PLEASE NOTE: CHOL will eventually replace HOL!
   723 
   724 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   725 It translates to the operator "split".  A new theory of integers is available;
   726 
   727 * In ZF, integer numerals now denote two's-complement binary integers.
   728 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   729 
   730 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   731 of the Axiom of Choice;
   732 
   733 
   734 
   735 New in Isabelle94-2
   736 -------------------
   737 
   738 * Significantly faster resolution;  
   739 
   740 * the different sections in a .thy file can now be mixed and repeated
   741 freely;
   742 
   743 * Database of theorems for FOL, HOL and ZF.  New
   744 commands including qed, qed_goal and bind_thm store theorems in the database.
   745 
   746 * Simple database queries: return a named theorem (get_thm) or all theorems of
   747 a given theory (thms_of), or find out what theory a theorem was proved in
   748 (theory_of_thm);
   749 
   750 * Bugs fixed in the inductive definition and datatype packages;
   751 
   752 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   753 and HOL_dup_cs obsolete;
   754 
   755 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   756 have been removed;
   757 
   758 * Simpler definition of function space in ZF;
   759 
   760 * new results about cardinal and ordinal arithmetic in ZF;
   761 
   762 * 'subtype' facility in HOL for introducing new types as subsets of existing
   763 types;
   764 
   765 
   766 $Id$