NEWS
author paulson
Thu Aug 06 10:50:44 1998 +0200 (1998-08-06)
changeset 5267 41a01176b9de
parent 5251 fee54d5c511c
child 5275 de5d5e5eb692
permissions -rw-r--r--
disjointness
     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;
    11 
    12 * HOL: major changes to the inductive and datatype packages;
    13 
    14 * HOL: renamed r^-1 to 'converse' from 'inverse'; `inj_onto' is now
    15 called `inj_on';
    16 
    17 
    18 *** Proof tools ***
    19 
    20 * Simplifier: Asm_full_simp_tac is now more aggressive.
    21   1. It will sometimes reorient premises if that increases their power to
    22      simplify.
    23   2. It does no longer proceed strictly from left to right but may also
    24      rotate premises to achieve further simplification.
    25   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    26   old Asm_full_simp_tac in that it does not rotate premises.
    27 
    28 * Classical reasoner: wrapper mechanism for the classical reasoner now
    29 allows for selected deletion of wrappers, by introduction of names for
    30 wrapper functionals.  This implies that addbefore, addSbefore,
    31 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    32 and that adding two tactics with the same name overwrites the first
    33 one (emitting a warning).
    34   type wrapper = (int -> tactic) -> (int -> tactic)
    35   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    36   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    37   delWrapper, delSWrapper: claset *  string            -> claset
    38   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    39 
    40 * HOL/split_all_tac is now much faster and fails if there is nothing
    41 to split.  Existing (fragile) proofs may require adaption because the
    42 order and the names of the automatically generated variables have
    43 changed.  split_all_tac has moved within claset() from unsafe wrappers
    44 to safe wrappers, which means that !!-bound variables are split much
    45 more aggressively, and safe_tac and clarify_tac now split such
    46 variables.  If this splitting is not appropriate, use delSWrapper
    47 "split_all_tac".
    48 
    49 * HOL/Simplifier:
    50 
    51  - Rewrite rules for case distinctions can now be added permanently to
    52    the default simpset using Addsplits just like Addsimps. They can be
    53    removed via Delsplits just like Delsimps. Lower-case versions are
    54    also available.
    55 
    56  - The rule split_if is now part of the default simpset. This means
    57    that the simplifier will eliminate all occurrences of if-then-else
    58    in the conclusion of a goal. To prevent this, you can either remove
    59    split_if completely from the default simpset by `Delsplits
    60    [split_if]' or remove it in a specific call of the simplifier using
    61    `... delsplits [split_if]'.  You can also add/delete other case
    62    splitting rules to/from the default simpset: every datatype
    63    generates suitable rules `split_t_case' and `split_t_case_asm'
    64    (where t is the name of the datatype).
    65 
    66 * Classical reasoner - Simplifier combination: new force_tac (and
    67 derivatives Force_tac, force) combines rewriting and classical
    68 reasoning (and whatever other tools) similarly to auto_tac, but is
    69 aimed to solve the given subgoal completely;
    70 
    71 
    72 *** General ***
    73 
    74 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
    75 and `goalw': the theory is no longer needed as an explicit argument -
    76 the current theory context is used; assumptions are no longer returned
    77 at the ML-level unless one of them starts with ==> or !!; it is
    78 recommended to convert to these new commands using isatool fixgoal
    79 (backup your sources first!);
    80 
    81 * new top-level commands 'thm' and 'thms' for retrieving theorems from
    82 the current theory context, and 'theory' to lookup stored theories;
    83 
    84 * new theory section 'nonterminals' for purely syntactic types;
    85 
    86 * new theory section 'setup' for generic ML setup functions
    87 (e.g. package initialization);
    88 
    89 * the distribution now includes Isabelle icons: see
    90 lib/logo/isabelle-{small,tiny}.xpm;
    91 
    92 
    93 *** HOL ***
    94 
    95 * HOL/inductive package reorganized and improved: now supports mutual
    96 definitions such as
    97 
    98   inductive EVEN ODD
    99     intrs
   100       null "0 : EVEN"
   101       oddI "n : EVEN ==> Suc n : ODD"
   102       evenI "n : ODD ==> Suc n : EVEN"
   103 
   104 new theorem list "elims" contains an elimination rule for each of the
   105 recursive sets; inductive definitions now handle disjunctive premises
   106 correctly (also ZF);
   107 
   108 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   109 "mutual_induct" no longer exists - the induction rule is always
   110 contained in "induct";
   111 
   112 
   113 * HOL/datatype package re-implemented and greatly improved: now
   114 supports mutually recursive datatypes such as
   115 
   116   datatype
   117     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   118             | SUM ('a aexp) ('a aexp)
   119             | DIFF ('a aexp) ('a aexp)
   120             | NUM 'a
   121   and
   122     'a bexp = LESS ('a aexp) ('a aexp)
   123             | AND ('a bexp) ('a bexp)
   124             | OR ('a bexp) ('a bexp)
   125 
   126 as well as indirectly recursive datatypes such as
   127 
   128   datatype
   129     ('a, 'b) term = Var 'a
   130                   | App 'b ((('a, 'b) term) list)
   131 
   132 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   133 induction on mutually / indirectly recursive datatypes.
   134 
   135 Primrec equations are now stored in theory and can be accessed via
   136 <function_name>.simps.
   137 
   138 INCOMPATIBILITIES:
   139 
   140   - Theories using datatypes must now have theory Datatype as an
   141     ancestor.
   142   - The specific <typename>.induct_tac no longer exists - use the
   143     generic induct_tac instead.
   144   - natE has been renamed to nat.exhaust - use exhaust_tac
   145     instead of res_inst_tac ... natE. Note that the variable
   146     names in nat.exhaust differ from the names in natE, this
   147     may cause some "fragile" proofs to fail.
   148   - The theorems split_<typename>_case and split_<typename>_case_asm
   149     have been renamed to <typename>.split and <typename>.split_asm.
   150   - Since default sorts of type variables are now handled correctly,
   151     some datatype definitions may have to be annotated with explicit
   152     sort constraints.
   153   - Primrec definitions no longer require function name and type
   154     of recursive argument.
   155 
   156 Consider using isatool fixdatatype to adapt your theories and proof
   157 scripts to the new package (backup your sources first!).
   158 
   159 
   160 * HOL/record package: now includes concrete syntax for record types,
   161 terms, updates; still lacks important theorems, like surjective
   162 pairing and split;
   163 
   164 * reorganized the main HOL image: HOL/Integ and String loaded by
   165 default; theory Main includes everything;
   166 
   167 * added option_map_eq_Some to the default simpset claset;
   168 
   169 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   170 
   171 * many new identities for unions, intersections, set difference, etc.;
   172 
   173 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   174 called split_if, split_split, split_sum_case and split_nat_case (to go
   175 with add/delsplits);
   176 
   177 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   178 (?x::unit) = (); this is made part of the default simpset, which COULD
   179 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   180 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   181 unit_abs_eta_conv is added in order to counter the effect of
   182 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   183 %u.f();
   184 
   185 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   186 makes more sense);
   187 
   188 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name was misleading);
   189 
   190 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   191 to 'converse' from 'inverse' (for compatibility with ZF and some
   192 literature);
   193 
   194 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   195 the well-founded relation;
   196 
   197 * HOL/Update: new theory of function updates:
   198     f(a:=b) == %x. if x=a then b else f x
   199 may also be iterated as in f(a:=b,c:=d,...);
   200 
   201 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   202 
   203 * HOL/List: new function list_update written xs[i:=v] that updates the i-th
   204   list position. May also be iterated as in xs[i:=a,j:=b,...].
   205 
   206 * HOL/Arith:
   207   - removed 'pred' (predecessor) function;
   208   - generalized some theorems about n-1;
   209   - many new laws about "div" and "mod";
   210   - new laws about greatest common divisors (see theory ex/Primes);
   211 
   212 * HOL/Relation: renamed the relational operator r^-1 "converse"
   213 instead of "inverse";
   214 
   215 * directory HOL/Real: a construction of the reals using Dedekind cuts
   216 (not included by default);
   217 
   218 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   219 
   220 * calling (stac rew i) now fails if "rew" has no effect on the goal
   221   [previously, this check worked only if the rewrite rule was unconditional]
   222 
   223 
   224 *** ZF ***
   225 
   226 * theory Main includes everything;
   227 
   228 * ZF INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name
   229   was misleading).  The rule and 'sym RS equals0E' are now in the default
   230   claset, giving automatic disjointness reasoning but breaking a few old 
   231   proofs.
   232 
   233 * ZF/Update: new theory of function updates
   234     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   235   may also be iterated as in f(a:=b,c:=d,...);
   236 
   237 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   238 
   239 * calling (stac rew i) now fails if "rew" has no effect on the goal
   240   [previously, this check worked only if the rewrite rule was unconditional]
   241 
   242 * case_tac provided for compatibility with HOL
   243     (like the old excluded_middle_tac, but with subgoals swapped)
   244 
   245 
   246 *** Internal programming interfaces ***
   247 
   248 * Pure: several new basic modules made available for general use, see
   249 also src/Pure/README;
   250 
   251 * improved the theory data mechanism to support encapsulation (data
   252 kind name replaced by private Object.kind, acting as authorization
   253 key); new type-safe user interface via functor TheoryDataFun;
   254 
   255 * removed global_names compatibility flag -- all theory declarations
   256 are qualified by default;
   257 
   258 * module Pure/Syntax now offers quote / antiquote translation
   259 functions (useful for Hoare logic etc. with implicit dependencies);
   260 
   261 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   262 cterm -> thm;
   263 
   264 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   265 subgoal;
   266 
   267 * Display.print_goals function moved to Locale.print_goals;
   268 
   269 
   270 
   271 New in Isabelle98 (January 1998)
   272 --------------------------------
   273 
   274 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   275 
   276 * changed lexical syntax of terms / types: dots made part of long
   277 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   278 
   279 * simpset (and claset) reference variable replaced by functions
   280 simpset / simpset_ref;
   281 
   282 * no longer supports theory aliases (via merge) and non-trivial
   283 implicit merge of thms' signatures;
   284 
   285 * most internal names of constants changed due to qualified names;
   286 
   287 * changed Pure/Sequence interface (see Pure/seq.ML);
   288 
   289 
   290 *** General Changes ***
   291 
   292 * hierachically structured name spaces (for consts, types, axms, thms
   293 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   294 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   295 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   296 long_names for fully qualified output names; NOTE: ML programs
   297 (special tactics, packages etc.) referring to internal names may have
   298 to be adapted to cope with fully qualified names; in case of severe
   299 backward campatibility problems try setting 'global_names' at compile
   300 time to have enrything declared within a flat name space; one may also
   301 fine tune name declarations in theories via the 'global' and 'local'
   302 section;
   303 
   304 * reimplemented the implicit simpset and claset using the new anytype
   305 data filed in signatures; references simpset:simpset ref etc. are
   306 replaced by functions simpset:unit->simpset and
   307 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   308 to patch your ML files accordingly;
   309 
   310 * HTML output now includes theory graph data for display with Java
   311 applet or isatool browser; data generated automatically via isatool
   312 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   313 
   314 * defs may now be conditional; improved rewrite_goals_tac to handle
   315 conditional equations;
   316 
   317 * defs now admits additional type arguments, using TYPE('a) syntax;
   318 
   319 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   320 creates a new theory node; implicit merge of thms' signatures is
   321 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   322 transfer:theory->thm->thm in (rare) cases;
   323 
   324 * improved handling of draft signatures / theories; draft thms (and
   325 ctyps, cterms) are automatically promoted to real ones;
   326 
   327 * slightly changed interfaces for oracles: admit many per theory, named
   328 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   329 
   330 * print_goals: optional output of const types (set show_consts and
   331 show_types);
   332 
   333 * improved output of warnings (###) and errors (***);
   334 
   335 * subgoal_tac displays a warning if the new subgoal has type variables;
   336 
   337 * removed old README and Makefiles;
   338 
   339 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   340 
   341 * removed obsolete init_pps and init_database;
   342 
   343 * deleted the obsolete tactical STATE, which was declared by
   344     fun STATE tacfun st = tacfun st st;
   345 
   346 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   347 (which abbreviates $HOME);
   348 
   349 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   350 use isatool fixseq to adapt your ML programs (this works for fully
   351 qualified references to the Sequence structure only!);
   352 
   353 * use_thy no longer requires writable current directory; it always
   354 reloads .ML *and* .thy file, if either one is out of date;
   355 
   356 
   357 *** Classical Reasoner ***
   358 
   359 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   360 tactics that use classical reasoning to simplify a subgoal without
   361 splitting it into several subgoals;
   362 
   363 * Safe_tac: like safe_tac but uses the default claset;
   364 
   365 
   366 *** Simplifier ***
   367 
   368 * added simplification meta rules:
   369     (asm_)(full_)simplify: simpset -> thm -> thm;
   370 
   371 * simplifier.ML no longer part of Pure -- has to be loaded by object
   372 logics (again);
   373 
   374 * added prems argument to simplification procedures;
   375 
   376 * HOL, FOL, ZF: added infix function `addsplits':
   377   instead of `<simpset> setloop (split_tac <thms>)'
   378   you can simply write `<simpset> addsplits <thms>'
   379 
   380 
   381 *** Syntax ***
   382 
   383 * TYPE('a) syntax for type reflection terms;
   384 
   385 * no longer handles consts with name "" -- declare as 'syntax' instead;
   386 
   387 * pretty printer: changed order of mixfix annotation preference (again!);
   388 
   389 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   390 
   391 
   392 *** HOL ***
   393 
   394 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   395   with `addloop' of the simplifier to faciliate case splitting in premises.
   396 
   397 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   398 
   399 * HOL/Auth: new protocol proofs including some for the Internet
   400   protocol TLS;
   401 
   402 * HOL/Map: new theory of `maps' a la VDM;
   403 
   404 * HOL/simplifier: simplification procedures nat_cancel_sums for
   405 cancelling out common nat summands from =, <, <= (in)equalities, or
   406 differences; simplification procedures nat_cancel_factor for
   407 cancelling common factor from =, <, <= (in)equalities over natural
   408 sums; nat_cancel contains both kinds of procedures, it is installed by
   409 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   410 
   411 * HOL/simplifier: terms of the form
   412   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   413   are rewritten to
   414   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   415   and those of the form
   416   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   417   are rewritten to
   418   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   419 
   420 * HOL/datatype
   421   Each datatype `t' now comes with a theorem `split_t_case' of the form
   422 
   423   P(t_case f1 ... fn x) =
   424      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   425         ...
   426        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   427      )
   428 
   429   and a theorem `split_t_case_asm' of the form
   430 
   431   P(t_case f1 ... fn x) =
   432     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   433         ...
   434        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   435      )
   436   which can be added to a simpset via `addsplits'. The existing theorems
   437   expand_list_case and expand_option_case have been renamed to
   438   split_list_case and split_option_case.
   439 
   440 * HOL/Arithmetic:
   441   - `pred n' is automatically converted to `n-1'.
   442     Users are strongly encouraged not to use `pred' any longer,
   443     because it will disappear altogether at some point.
   444   - Users are strongly encouraged to write "0 < n" rather than
   445     "n ~= 0". Theorems and proof tools have been modified towards this
   446     `standard'.
   447 
   448 * HOL/Lists:
   449   the function "set_of_list" has been renamed "set" (and its theorems too);
   450   the function "nth" now takes its arguments in the reverse order and
   451   has acquired the infix notation "!" as in "xs!n".
   452 
   453 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   454 
   455 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   456   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   457 
   458 * HOL/record: extensible records with schematic structural subtyping
   459 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   460 still lacks various theorems and concrete record syntax;
   461 
   462 
   463 *** HOLCF ***
   464 
   465 * removed "axioms" and "generated by" sections;
   466 
   467 * replaced "ops" section by extended "consts" section, which is capable of
   468   handling the continuous function space "->" directly;
   469 
   470 * domain package:
   471   . proves theorems immediately and stores them in the theory,
   472   . creates hierachical name space,
   473   . now uses normal mixfix annotations (instead of cinfix...),
   474   . minor changes to some names and values (for consistency),
   475   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   476   . separator between mutual domain defs: changed "," to "and",
   477   . improved handling of sort constraints;  now they have to
   478     appear on the left-hand side of the equations only;
   479 
   480 * fixed LAM <x,y,zs>.b syntax;
   481 
   482 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   483 adm (%x. P (t x)), where P is chainfinite and t continuous;
   484 
   485 
   486 *** FOL and ZF ***
   487 
   488 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   489   with `addloop' of the simplifier to faciliate case splitting in premises.
   490 
   491 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   492 in HOL, they strip ALL and --> from proved theorems;
   493 
   494 
   495 
   496 New in Isabelle94-8 (May 1997)
   497 ------------------------------
   498 
   499 *** General Changes ***
   500 
   501 * new utilities to build / run / maintain Isabelle etc. (in parts
   502 still somewhat experimental); old Makefiles etc. still functional;
   503 
   504 * new 'Isabelle System Manual';
   505 
   506 * INSTALL text, together with ./configure and ./build scripts;
   507 
   508 * reimplemented type inference for greater efficiency, better error
   509 messages and clean internal interface;
   510 
   511 * prlim command for dealing with lots of subgoals (an easier way of
   512 setting goals_limit);
   513 
   514 
   515 *** Syntax ***
   516 
   517 * supports alternative (named) syntax tables (parser and pretty
   518 printer); internal interface is provided by add_modesyntax(_i);
   519 
   520 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   521 be used in conjunction with the Isabelle symbol font; uses the
   522 "symbols" syntax table;
   523 
   524 * added token_translation interface (may translate name tokens in
   525 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   526 the current print_mode); IMPORTANT: user print translation functions
   527 are responsible for marking newly introduced bounds
   528 (Syntax.mark_boundT);
   529 
   530 * token translations for modes "xterm" and "xterm_color" that display
   531 names in bold, underline etc. or colors (which requires a color
   532 version of xterm);
   533 
   534 * infixes may now be declared with names independent of their syntax;
   535 
   536 * added typed_print_translation (like print_translation, but may
   537 access type of constant);
   538 
   539 
   540 *** Classical Reasoner ***
   541 
   542 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   543 some limitations.  Blast_tac...
   544   + ignores addss, addbefore, addafter; this restriction is intrinsic
   545   + ignores elimination rules that don't have the correct format
   546 	(the conclusion MUST be a formula variable)
   547   + ignores types, which can make HOL proofs fail
   548   + rules must not require higher-order unification, e.g. apply_type in ZF
   549     [message "Function Var's argument not a bound variable" relates to this]
   550   + its proof strategy is more general but can actually be slower
   551 
   552 * substitution with equality assumptions no longer permutes other
   553 assumptions;
   554 
   555 * minor changes in semantics of addafter (now called addaltern); renamed
   556 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   557 (and access functions for it);
   558 
   559 * improved combination of classical reasoner and simplifier: 
   560   + functions for handling clasimpsets
   561   + improvement of addss: now the simplifier is called _after_ the
   562     safe steps.
   563   + safe variant of addss called addSss: uses safe simplifications
   564     _during_ the safe steps. It is more complete as it allows multiple 
   565     instantiations of unknowns (e.g. with slow_tac).
   566 
   567 *** Simplifier ***
   568 
   569 * added interface for simplification procedures (functions that
   570 produce *proven* rewrite rules on the fly, depending on current
   571 redex);
   572 
   573 * ordering on terms as parameter (used for ordered rewriting);
   574 
   575 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   576 
   577 * the solver is now split into a safe and an unsafe part.
   578 This should be invisible for the normal user, except that the
   579 functions setsolver and addsolver have been renamed to setSolver and
   580 addSolver; added safe_asm_full_simp_tac;
   581 
   582 
   583 *** HOL ***
   584 
   585 * a generic induction tactic `induct_tac' which works for all datatypes and
   586 also for type `nat';
   587 
   588 * a generic case distinction tactic `exhaust_tac' which works for all
   589 datatypes and also for type `nat';
   590 
   591 * each datatype comes with a function `size';
   592 
   593 * patterns in case expressions allow tuple patterns as arguments to
   594 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   595 
   596 * primrec now also works with type nat;
   597 
   598 * recdef: a new declaration form, allows general recursive functions to be
   599 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   600 
   601 * the constant for negation has been renamed from "not" to "Not" to
   602 harmonize with FOL, ZF, LK, etc.;
   603 
   604 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   605 infinite lists;
   606 
   607 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   608 
   609 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   610 problems in commutative rings, using axiomatic type classes for + and *;
   611 
   612 * more examples in HOL/MiniML and HOL/Auth;
   613 
   614 * more default rewrite rules for quantifiers, union/intersection;
   615 
   616 * a new constant `arbitrary == @x.False';
   617 
   618 * HOLCF/IOA replaces old HOL/IOA;
   619 
   620 * HOLCF changes: derived all rules and arities 
   621   + axiomatic type classes instead of classes 
   622   + typedef instead of faking type definitions
   623   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   624   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   625   + eliminated the types void, one, tr
   626   + use unit lift and bool lift (with translations) instead of one and tr
   627   + eliminated blift from Lift3.thy (use Def instead of blift)
   628   all eliminated rules are derived as theorems --> no visible changes ;
   629 
   630 
   631 *** ZF ***
   632 
   633 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   634 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   635 as ZF_cs addSIs [equalityI];
   636 
   637 
   638 
   639 New in Isabelle94-7 (November 96)
   640 ---------------------------------
   641 
   642 * allowing negative levels (as offsets) in prlev and choplev;
   643 
   644 * super-linear speedup for large simplifications;
   645 
   646 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   647 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   648 FAIL); can suppress it using the command Delsimps (ex_simps @
   649 all_simps); De Morgan laws are also now included, by default;
   650 
   651 * improved printing of ==>  :  ~:
   652 
   653 * new object-logic "Sequents" adds linear logic, while replacing LK
   654 and Modal (thanks to Sara Kalvala);
   655 
   656 * HOL/Auth: correctness proofs for authentication protocols;
   657 
   658 * HOL: new auto_tac combines rewriting and classical reasoning (many
   659 examples on HOL/Auth);
   660 
   661 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   662 the rewriter and classical reasoner simultaneously;
   663 
   664 * function uresult no longer returns theorems in "standard" format;
   665 regain previous version by: val uresult = standard o uresult;
   666 
   667 
   668 
   669 New in Isabelle94-6
   670 -------------------
   671 
   672 * oracles -- these establish an interface between Isabelle and trusted
   673 external reasoners, which may deliver results as theorems;
   674 
   675 * proof objects (in particular record all uses of oracles);
   676 
   677 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   678 
   679 * "constdefs" section in theory files;
   680 
   681 * "primrec" section (HOL) no longer requires names;
   682 
   683 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   684 
   685 
   686 
   687 New in Isabelle94-5
   688 -------------------
   689 
   690 * reduced space requirements;
   691 
   692 * automatic HTML generation from theories;
   693 
   694 * theory files no longer require "..." (quotes) around most types;
   695 
   696 * new examples, including two proofs of the Church-Rosser theorem;
   697 
   698 * non-curried (1994) version of HOL is no longer distributed;
   699 
   700 
   701 
   702 New in Isabelle94-4
   703 -------------------
   704 
   705 * greatly reduced space requirements;
   706 
   707 * theory files (.thy) no longer require \...\ escapes at line breaks;
   708 
   709 * searchable theorem database (see the section "Retrieving theorems" on 
   710 page 8 of the Reference Manual);
   711 
   712 * new examples, including Grabczewski's monumental case study of the
   713 Axiom of Choice;
   714 
   715 * The previous version of HOL renamed to Old_HOL;
   716 
   717 * The new version of HOL (previously called CHOL) uses a curried syntax 
   718 for functions.  Application looks like f a b instead of f(a,b);
   719 
   720 * Mutually recursive inductive definitions finally work in HOL;
   721 
   722 * In ZF, pattern-matching on tuples is now available in all abstractions and
   723 translates to the operator "split";
   724 
   725 
   726 
   727 New in Isabelle94-3
   728 -------------------
   729 
   730 * new infix operator, addss, allowing the classical reasoner to 
   731 perform simplification at each step of its search.  Example:
   732 	fast_tac (cs addss ss)
   733 
   734 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   735 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   736 look like (a,b) instead of <a,b>;
   737 
   738 * PLEASE NOTE: CHOL will eventually replace HOL!
   739 
   740 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   741 It translates to the operator "split".  A new theory of integers is available;
   742 
   743 * In ZF, integer numerals now denote two's-complement binary integers.
   744 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   745 
   746 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   747 of the Axiom of Choice;
   748 
   749 
   750 
   751 New in Isabelle94-2
   752 -------------------
   753 
   754 * Significantly faster resolution;  
   755 
   756 * the different sections in a .thy file can now be mixed and repeated
   757 freely;
   758 
   759 * Database of theorems for FOL, HOL and ZF.  New
   760 commands including qed, qed_goal and bind_thm store theorems in the database.
   761 
   762 * Simple database queries: return a named theorem (get_thm) or all theorems of
   763 a given theory (thms_of), or find out what theory a theorem was proved in
   764 (theory_of_thm);
   765 
   766 * Bugs fixed in the inductive definition and datatype packages;
   767 
   768 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   769 and HOL_dup_cs obsolete;
   770 
   771 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   772 have been removed;
   773 
   774 * Simpler definition of function space in ZF;
   775 
   776 * new results about cardinal and ordinal arithmetic in ZF;
   777 
   778 * 'subtype' facility in HOL for introducing new types as subsets of existing
   779 types;
   780 
   781 
   782 $Id$