NEWS
author nipkow
Sat Aug 08 14:12:25 1998 +0200 (1998-08-08)
changeset 5282 80c75c862a8f
parent 5275 de5d5e5eb692
child 5308 3ca4da83012c
permissions -rw-r--r--
*** empty log message ***
     1 Isabelle NEWS -- history of user-visible changes
     2 ================================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     8 
     9 * several changes of proof tools;
    10 
    11 * HOL: major changes to the inductive and datatype packages;
    12 
    13 * HOL: renamed r^-1 to 'converse' from 'inverse'; `inj_onto' is now
    14 called `inj_on';
    15 
    16 * HOL: removed duplicate thms in Arith:
    17   less_imp_add_less  should be replaced by  trans_less_add1
    18   le_imp_add_le      should be replaced by  trans_le_add1
    19 
    20 *** Proof tools ***
    21 
    22 * Simplifier: Asm_full_simp_tac is now more aggressive.
    23   1. It will sometimes reorient premises if that increases their power to
    24      simplify.
    25   2. It does no longer proceed strictly from left to right but may also
    26      rotate premises to achieve further simplification.
    27   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    28   old Asm_full_simp_tac in that it does not rotate premises.
    29 
    30 * Classical reasoner: wrapper mechanism for the classical reasoner now
    31 allows for selected deletion of wrappers, by introduction of names for
    32 wrapper functionals.  This implies that addbefore, addSbefore,
    33 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    34 and that adding two tactics with the same name overwrites the first
    35 one (emitting a warning).
    36   type wrapper = (int -> tactic) -> (int -> tactic)
    37   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    38   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    39   delWrapper, delSWrapper: claset *  string            -> claset
    40   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    41 
    42 * HOL/split_all_tac is now much faster and fails if there is nothing
    43 to split.  Existing (fragile) proofs may require adaption because the
    44 order and the names of the automatically generated variables have
    45 changed.  split_all_tac has moved within claset() from unsafe wrappers
    46 to safe wrappers, which means that !!-bound variables are split much
    47 more aggressively, and safe_tac and clarify_tac now split such
    48 variables.  If this splitting is not appropriate, use delSWrapper
    49 "split_all_tac".
    50 
    51 * HOL/Simplifier:
    52 
    53  - Rewrite rules for case distinctions can now be added permanently to
    54    the default simpset using Addsplits just like Addsimps. They can be
    55    removed via Delsplits just like Delsimps. Lower-case versions are
    56    also available.
    57 
    58  - The rule split_if is now part of the default simpset. This means
    59    that the simplifier will eliminate all occurrences of if-then-else
    60    in the conclusion of a goal. To prevent this, you can either remove
    61    split_if completely from the default simpset by `Delsplits
    62    [split_if]' or remove it in a specific call of the simplifier using
    63    `... delsplits [split_if]'.  You can also add/delete other case
    64    splitting rules to/from the default simpset: every datatype
    65    generates suitable rules `split_t_case' and `split_t_case_asm'
    66    (where t is the name of the datatype).
    67 
    68 * Classical reasoner - Simplifier combination: new force_tac (and
    69 derivatives Force_tac, force) combines rewriting and classical
    70 reasoning (and whatever other tools) similarly to auto_tac, but is
    71 aimed to solve the given subgoal completely;
    72 
    73 
    74 *** General ***
    75 
    76 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
    77 and `goalw': the theory is no longer needed as an explicit argument -
    78 the current theory context is used; assumptions are no longer returned
    79 at the ML-level unless one of them starts with ==> or !!; it is
    80 recommended to convert to these new commands using isatool fixgoal
    81 (backup your sources first!);
    82 
    83 * new top-level commands 'thm' and 'thms' for retrieving theorems from
    84 the current theory context, and 'theory' to lookup stored theories;
    85 
    86 * new theory section 'nonterminals' for purely syntactic types;
    87 
    88 * new theory section 'setup' for generic ML setup functions
    89 (e.g. package initialization);
    90 
    91 * the distribution now includes Isabelle icons: see
    92 lib/logo/isabelle-{small,tiny}.xpm;
    93 
    94 
    95 *** HOL ***
    96 
    97 * HOL/inductive package reorganized and improved: now supports mutual
    98 definitions such as
    99 
   100   inductive EVEN ODD
   101     intrs
   102       null "0 : EVEN"
   103       oddI "n : EVEN ==> Suc n : ODD"
   104       evenI "n : ODD ==> Suc n : EVEN"
   105 
   106 new theorem list "elims" contains an elimination rule for each of the
   107 recursive sets; inductive definitions now handle disjunctive premises
   108 correctly (also ZF);
   109 
   110 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   111 "mutual_induct" no longer exists - the induction rule is always
   112 contained in "induct";
   113 
   114 
   115 * HOL/datatype package re-implemented and greatly improved: now
   116 supports mutually 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  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   135 induction on mutually / indirectly recursive datatypes.
   136 
   137 Primrec equations are now stored in theory and can be accessed via
   138 <function_name>.simps.
   139 
   140 INCOMPATIBILITIES:
   141 
   142   - Theories using datatypes must now have theory Datatype as an
   143     ancestor.
   144   - The specific <typename>.induct_tac no longer exists - use the
   145     generic induct_tac instead.
   146   - natE has been renamed to nat.exhaust - use exhaust_tac
   147     instead of res_inst_tac ... natE. Note that the variable
   148     names in nat.exhaust differ from the names in natE, this
   149     may cause some "fragile" proofs to fail.
   150   - The theorems split_<typename>_case and split_<typename>_case_asm
   151     have been renamed to <typename>.split and <typename>.split_asm.
   152   - Since default sorts of type variables are now handled correctly,
   153     some datatype definitions may have to be annotated with explicit
   154     sort constraints.
   155   - Primrec definitions no longer require function name and type
   156     of recursive argument.
   157 
   158 Consider using isatool fixdatatype to adapt your theories and proof
   159 scripts to the new package (backup your sources first!).
   160 
   161 
   162 * HOL/record package: now includes concrete syntax for record types,
   163 terms, updates; still lacks important theorems, like surjective
   164 pairing and split;
   165 
   166 * reorganized the main HOL image: HOL/Integ and String loaded by
   167 default; theory Main includes everything;
   168 
   169 * added option_map_eq_Some to the default simpset claset;
   170 
   171 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   172 
   173 * many new identities for unions, intersections, set difference, etc.;
   174 
   175 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   176 called split_if, split_split, split_sum_case and split_nat_case (to go
   177 with add/delsplits);
   178 
   179 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   180 (?x::unit) = (); this is made part of the default simpset, which COULD
   181 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   182 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   183 unit_abs_eta_conv is added in order to counter the effect of
   184 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   185 %u.f();
   186 
   187 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   188 makes more sense);
   189 
   190 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name was misleading);
   191 
   192 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   193 to 'converse' from 'inverse' (for compatibility with ZF and some
   194 literature);
   195 
   196 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   197 the well-founded relation;
   198 
   199 * HOL/Update: new theory of function updates:
   200     f(a:=b) == %x. if x=a then b else f x
   201 may also be iterated as in f(a:=b,c:=d,...);
   202 
   203 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   204 
   205 * HOL/List:
   206   - new function list_update written xs[i:=v] that updates the i-th
   207     list position. May also be iterated as in xs[i:=a,j:=b,...].
   208   - new lexicographic orderings and corresponding wellfoundedness theorems.
   209 
   210 * HOL/Arith:
   211   - removed 'pred' (predecessor) function;
   212   - generalized some theorems about n-1;
   213   - many new laws about "div" and "mod";
   214   - new laws about greatest common divisors (see theory ex/Primes);
   215 
   216 * HOL/Relation: renamed the relational operator r^-1 "converse"
   217 instead of "inverse";
   218 
   219 * directory HOL/Real: a construction of the reals using Dedekind cuts
   220 (not included by default);
   221 
   222 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   223 
   224 * calling (stac rew i) now fails if "rew" has no effect on the goal
   225   [previously, this check worked only if the rewrite rule was unconditional]
   226 
   227 
   228 *** ZF ***
   229 
   230 * theory Main includes everything;
   231 
   232 * ZF INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name
   233   was misleading).  The rule and 'sym RS equals0E' are now in the default
   234   claset, giving automatic disjointness reasoning but breaking a few old 
   235   proofs.
   236 
   237 * ZF/Update: new theory of function updates
   238     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   239   may also be iterated as in f(a:=b,c:=d,...);
   240 
   241 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   242 
   243 * calling (stac rew i) now fails if "rew" has no effect on the goal
   244   [previously, this check worked only if the rewrite rule was unconditional]
   245 
   246 * case_tac provided for compatibility with HOL
   247     (like the old excluded_middle_tac, but with subgoals swapped)
   248 
   249 
   250 *** Internal programming interfaces ***
   251 
   252 * Pure: several new basic modules made available for general use, see
   253 also src/Pure/README;
   254 
   255 * improved the theory data mechanism to support encapsulation (data
   256 kind name replaced by private Object.kind, acting as authorization
   257 key); new type-safe user interface via functor TheoryDataFun;
   258 
   259 * removed global_names compatibility flag -- all theory declarations
   260 are qualified by default;
   261 
   262 * module Pure/Syntax now offers quote / antiquote translation
   263 functions (useful for Hoare logic etc. with implicit dependencies);
   264 
   265 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   266 cterm -> thm;
   267 
   268 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   269 subgoal;
   270 
   271 * Display.print_goals function moved to Locale.print_goals;
   272 
   273 
   274 
   275 New in Isabelle98 (January 1998)
   276 --------------------------------
   277 
   278 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   279 
   280 * changed lexical syntax of terms / types: dots made part of long
   281 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   282 
   283 * simpset (and claset) reference variable replaced by functions
   284 simpset / simpset_ref;
   285 
   286 * no longer supports theory aliases (via merge) and non-trivial
   287 implicit merge of thms' signatures;
   288 
   289 * most internal names of constants changed due to qualified names;
   290 
   291 * changed Pure/Sequence interface (see Pure/seq.ML);
   292 
   293 
   294 *** General Changes ***
   295 
   296 * hierachically structured name spaces (for consts, types, axms, thms
   297 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   298 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   299 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   300 long_names for fully qualified output names; NOTE: ML programs
   301 (special tactics, packages etc.) referring to internal names may have
   302 to be adapted to cope with fully qualified names; in case of severe
   303 backward campatibility problems try setting 'global_names' at compile
   304 time to have enrything declared within a flat name space; one may also
   305 fine tune name declarations in theories via the 'global' and 'local'
   306 section;
   307 
   308 * reimplemented the implicit simpset and claset using the new anytype
   309 data filed in signatures; references simpset:simpset ref etc. are
   310 replaced by functions simpset:unit->simpset and
   311 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   312 to patch your ML files accordingly;
   313 
   314 * HTML output now includes theory graph data for display with Java
   315 applet or isatool browser; data generated automatically via isatool
   316 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   317 
   318 * defs may now be conditional; improved rewrite_goals_tac to handle
   319 conditional equations;
   320 
   321 * defs now admits additional type arguments, using TYPE('a) syntax;
   322 
   323 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   324 creates a new theory node; implicit merge of thms' signatures is
   325 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   326 transfer:theory->thm->thm in (rare) cases;
   327 
   328 * improved handling of draft signatures / theories; draft thms (and
   329 ctyps, cterms) are automatically promoted to real ones;
   330 
   331 * slightly changed interfaces for oracles: admit many per theory, named
   332 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   333 
   334 * print_goals: optional output of const types (set show_consts and
   335 show_types);
   336 
   337 * improved output of warnings (###) and errors (***);
   338 
   339 * subgoal_tac displays a warning if the new subgoal has type variables;
   340 
   341 * removed old README and Makefiles;
   342 
   343 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   344 
   345 * removed obsolete init_pps and init_database;
   346 
   347 * deleted the obsolete tactical STATE, which was declared by
   348     fun STATE tacfun st = tacfun st st;
   349 
   350 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   351 (which abbreviates $HOME);
   352 
   353 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   354 use isatool fixseq to adapt your ML programs (this works for fully
   355 qualified references to the Sequence structure only!);
   356 
   357 * use_thy no longer requires writable current directory; it always
   358 reloads .ML *and* .thy file, if either one is out of date;
   359 
   360 
   361 *** Classical Reasoner ***
   362 
   363 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   364 tactics that use classical reasoning to simplify a subgoal without
   365 splitting it into several subgoals;
   366 
   367 * Safe_tac: like safe_tac but uses the default claset;
   368 
   369 
   370 *** Simplifier ***
   371 
   372 * added simplification meta rules:
   373     (asm_)(full_)simplify: simpset -> thm -> thm;
   374 
   375 * simplifier.ML no longer part of Pure -- has to be loaded by object
   376 logics (again);
   377 
   378 * added prems argument to simplification procedures;
   379 
   380 * HOL, FOL, ZF: added infix function `addsplits':
   381   instead of `<simpset> setloop (split_tac <thms>)'
   382   you can simply write `<simpset> addsplits <thms>'
   383 
   384 
   385 *** Syntax ***
   386 
   387 * TYPE('a) syntax for type reflection terms;
   388 
   389 * no longer handles consts with name "" -- declare as 'syntax' instead;
   390 
   391 * pretty printer: changed order of mixfix annotation preference (again!);
   392 
   393 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   394 
   395 
   396 *** HOL ***
   397 
   398 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   399   with `addloop' of the simplifier to faciliate case splitting in premises.
   400 
   401 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   402 
   403 * HOL/Auth: new protocol proofs including some for the Internet
   404   protocol TLS;
   405 
   406 * HOL/Map: new theory of `maps' a la VDM;
   407 
   408 * HOL/simplifier: simplification procedures nat_cancel_sums for
   409 cancelling out common nat summands from =, <, <= (in)equalities, or
   410 differences; simplification procedures nat_cancel_factor for
   411 cancelling common factor from =, <, <= (in)equalities over natural
   412 sums; nat_cancel contains both kinds of procedures, it is installed by
   413 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   414 
   415 * HOL/simplifier: terms of the form
   416   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   417   are rewritten to
   418   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   419   and those of the form
   420   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   421   are rewritten to
   422   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   423 
   424 * HOL/datatype
   425   Each datatype `t' now comes with a theorem `split_t_case' of the form
   426 
   427   P(t_case f1 ... fn x) =
   428      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   429         ...
   430        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   431      )
   432 
   433   and a theorem `split_t_case_asm' of the form
   434 
   435   P(t_case f1 ... fn x) =
   436     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   437         ...
   438        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   439      )
   440   which can be added to a simpset via `addsplits'. The existing theorems
   441   expand_list_case and expand_option_case have been renamed to
   442   split_list_case and split_option_case.
   443 
   444 * HOL/Arithmetic:
   445   - `pred n' is automatically converted to `n-1'.
   446     Users are strongly encouraged not to use `pred' any longer,
   447     because it will disappear altogether at some point.
   448   - Users are strongly encouraged to write "0 < n" rather than
   449     "n ~= 0". Theorems and proof tools have been modified towards this
   450     `standard'.
   451 
   452 * HOL/Lists:
   453   the function "set_of_list" has been renamed "set" (and its theorems too);
   454   the function "nth" now takes its arguments in the reverse order and
   455   has acquired the infix notation "!" as in "xs!n".
   456 
   457 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   458 
   459 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   460   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   461 
   462 * HOL/record: extensible records with schematic structural subtyping
   463 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   464 still lacks various theorems and concrete record syntax;
   465 
   466 
   467 *** HOLCF ***
   468 
   469 * removed "axioms" and "generated by" sections;
   470 
   471 * replaced "ops" section by extended "consts" section, which is capable of
   472   handling the continuous function space "->" directly;
   473 
   474 * domain package:
   475   . proves theorems immediately and stores them in the theory,
   476   . creates hierachical name space,
   477   . now uses normal mixfix annotations (instead of cinfix...),
   478   . minor changes to some names and values (for consistency),
   479   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   480   . separator between mutual domain defs: changed "," to "and",
   481   . improved handling of sort constraints;  now they have to
   482     appear on the left-hand side of the equations only;
   483 
   484 * fixed LAM <x,y,zs>.b syntax;
   485 
   486 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   487 adm (%x. P (t x)), where P is chainfinite and t continuous;
   488 
   489 
   490 *** FOL and ZF ***
   491 
   492 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   493   with `addloop' of the simplifier to faciliate case splitting in premises.
   494 
   495 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   496 in HOL, they strip ALL and --> from proved theorems;
   497 
   498 
   499 
   500 New in Isabelle94-8 (May 1997)
   501 ------------------------------
   502 
   503 *** General Changes ***
   504 
   505 * new utilities to build / run / maintain Isabelle etc. (in parts
   506 still somewhat experimental); old Makefiles etc. still functional;
   507 
   508 * new 'Isabelle System Manual';
   509 
   510 * INSTALL text, together with ./configure and ./build scripts;
   511 
   512 * reimplemented type inference for greater efficiency, better error
   513 messages and clean internal interface;
   514 
   515 * prlim command for dealing with lots of subgoals (an easier way of
   516 setting goals_limit);
   517 
   518 
   519 *** Syntax ***
   520 
   521 * supports alternative (named) syntax tables (parser and pretty
   522 printer); internal interface is provided by add_modesyntax(_i);
   523 
   524 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   525 be used in conjunction with the Isabelle symbol font; uses the
   526 "symbols" syntax table;
   527 
   528 * added token_translation interface (may translate name tokens in
   529 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   530 the current print_mode); IMPORTANT: user print translation functions
   531 are responsible for marking newly introduced bounds
   532 (Syntax.mark_boundT);
   533 
   534 * token translations for modes "xterm" and "xterm_color" that display
   535 names in bold, underline etc. or colors (which requires a color
   536 version of xterm);
   537 
   538 * infixes may now be declared with names independent of their syntax;
   539 
   540 * added typed_print_translation (like print_translation, but may
   541 access type of constant);
   542 
   543 
   544 *** Classical Reasoner ***
   545 
   546 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   547 some limitations.  Blast_tac...
   548   + ignores addss, addbefore, addafter; this restriction is intrinsic
   549   + ignores elimination rules that don't have the correct format
   550 	(the conclusion MUST be a formula variable)
   551   + ignores types, which can make HOL proofs fail
   552   + rules must not require higher-order unification, e.g. apply_type in ZF
   553     [message "Function Var's argument not a bound variable" relates to this]
   554   + its proof strategy is more general but can actually be slower
   555 
   556 * substitution with equality assumptions no longer permutes other
   557 assumptions;
   558 
   559 * minor changes in semantics of addafter (now called addaltern); renamed
   560 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   561 (and access functions for it);
   562 
   563 * improved combination of classical reasoner and simplifier: 
   564   + functions for handling clasimpsets
   565   + improvement of addss: now the simplifier is called _after_ the
   566     safe steps.
   567   + safe variant of addss called addSss: uses safe simplifications
   568     _during_ the safe steps. It is more complete as it allows multiple 
   569     instantiations of unknowns (e.g. with slow_tac).
   570 
   571 *** Simplifier ***
   572 
   573 * added interface for simplification procedures (functions that
   574 produce *proven* rewrite rules on the fly, depending on current
   575 redex);
   576 
   577 * ordering on terms as parameter (used for ordered rewriting);
   578 
   579 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   580 
   581 * the solver is now split into a safe and an unsafe part.
   582 This should be invisible for the normal user, except that the
   583 functions setsolver and addsolver have been renamed to setSolver and
   584 addSolver; added safe_asm_full_simp_tac;
   585 
   586 
   587 *** HOL ***
   588 
   589 * a generic induction tactic `induct_tac' which works for all datatypes and
   590 also for type `nat';
   591 
   592 * a generic case distinction tactic `exhaust_tac' which works for all
   593 datatypes and also for type `nat';
   594 
   595 * each datatype comes with a function `size';
   596 
   597 * patterns in case expressions allow tuple patterns as arguments to
   598 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   599 
   600 * primrec now also works with type nat;
   601 
   602 * recdef: a new declaration form, allows general recursive functions to be
   603 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   604 
   605 * the constant for negation has been renamed from "not" to "Not" to
   606 harmonize with FOL, ZF, LK, etc.;
   607 
   608 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   609 infinite lists;
   610 
   611 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   612 
   613 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   614 problems in commutative rings, using axiomatic type classes for + and *;
   615 
   616 * more examples in HOL/MiniML and HOL/Auth;
   617 
   618 * more default rewrite rules for quantifiers, union/intersection;
   619 
   620 * a new constant `arbitrary == @x.False';
   621 
   622 * HOLCF/IOA replaces old HOL/IOA;
   623 
   624 * HOLCF changes: derived all rules and arities 
   625   + axiomatic type classes instead of classes 
   626   + typedef instead of faking type definitions
   627   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   628   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   629   + eliminated the types void, one, tr
   630   + use unit lift and bool lift (with translations) instead of one and tr
   631   + eliminated blift from Lift3.thy (use Def instead of blift)
   632   all eliminated rules are derived as theorems --> no visible changes ;
   633 
   634 
   635 *** ZF ***
   636 
   637 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   638 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   639 as ZF_cs addSIs [equalityI];
   640 
   641 
   642 
   643 New in Isabelle94-7 (November 96)
   644 ---------------------------------
   645 
   646 * allowing negative levels (as offsets) in prlev and choplev;
   647 
   648 * super-linear speedup for large simplifications;
   649 
   650 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   651 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   652 FAIL); can suppress it using the command Delsimps (ex_simps @
   653 all_simps); De Morgan laws are also now included, by default;
   654 
   655 * improved printing of ==>  :  ~:
   656 
   657 * new object-logic "Sequents" adds linear logic, while replacing LK
   658 and Modal (thanks to Sara Kalvala);
   659 
   660 * HOL/Auth: correctness proofs for authentication protocols;
   661 
   662 * HOL: new auto_tac combines rewriting and classical reasoning (many
   663 examples on HOL/Auth);
   664 
   665 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   666 the rewriter and classical reasoner simultaneously;
   667 
   668 * function uresult no longer returns theorems in "standard" format;
   669 regain previous version by: val uresult = standard o uresult;
   670 
   671 
   672 
   673 New in Isabelle94-6
   674 -------------------
   675 
   676 * oracles -- these establish an interface between Isabelle and trusted
   677 external reasoners, which may deliver results as theorems;
   678 
   679 * proof objects (in particular record all uses of oracles);
   680 
   681 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   682 
   683 * "constdefs" section in theory files;
   684 
   685 * "primrec" section (HOL) no longer requires names;
   686 
   687 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   688 
   689 
   690 
   691 New in Isabelle94-5
   692 -------------------
   693 
   694 * reduced space requirements;
   695 
   696 * automatic HTML generation from theories;
   697 
   698 * theory files no longer require "..." (quotes) around most types;
   699 
   700 * new examples, including two proofs of the Church-Rosser theorem;
   701 
   702 * non-curried (1994) version of HOL is no longer distributed;
   703 
   704 
   705 
   706 New in Isabelle94-4
   707 -------------------
   708 
   709 * greatly reduced space requirements;
   710 
   711 * theory files (.thy) no longer require \...\ escapes at line breaks;
   712 
   713 * searchable theorem database (see the section "Retrieving theorems" on 
   714 page 8 of the Reference Manual);
   715 
   716 * new examples, including Grabczewski's monumental case study of the
   717 Axiom of Choice;
   718 
   719 * The previous version of HOL renamed to Old_HOL;
   720 
   721 * The new version of HOL (previously called CHOL) uses a curried syntax 
   722 for functions.  Application looks like f a b instead of f(a,b);
   723 
   724 * Mutually recursive inductive definitions finally work in HOL;
   725 
   726 * In ZF, pattern-matching on tuples is now available in all abstractions and
   727 translates to the operator "split";
   728 
   729 
   730 
   731 New in Isabelle94-3
   732 -------------------
   733 
   734 * new infix operator, addss, allowing the classical reasoner to 
   735 perform simplification at each step of its search.  Example:
   736 	fast_tac (cs addss ss)
   737 
   738 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   739 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   740 look like (a,b) instead of <a,b>;
   741 
   742 * PLEASE NOTE: CHOL will eventually replace HOL!
   743 
   744 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   745 It translates to the operator "split".  A new theory of integers is available;
   746 
   747 * In ZF, integer numerals now denote two's-complement binary integers.
   748 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   749 
   750 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   751 of the Axiom of Choice;
   752 
   753 
   754 
   755 New in Isabelle94-2
   756 -------------------
   757 
   758 * Significantly faster resolution;  
   759 
   760 * the different sections in a .thy file can now be mixed and repeated
   761 freely;
   762 
   763 * Database of theorems for FOL, HOL and ZF.  New
   764 commands including qed, qed_goal and bind_thm store theorems in the database.
   765 
   766 * Simple database queries: return a named theorem (get_thm) or all theorems of
   767 a given theory (thms_of), or find out what theory a theorem was proved in
   768 (theory_of_thm);
   769 
   770 * Bugs fixed in the inductive definition and datatype packages;
   771 
   772 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   773 and HOL_dup_cs obsolete;
   774 
   775 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   776 have been removed;
   777 
   778 * Simpler definition of function space in ZF;
   779 
   780 * new results about cardinal and ordinal arithmetic in ZF;
   781 
   782 * 'subtype' facility in HOL for introducing new types as subsets of existing
   783 types;
   784 
   785 
   786 $Id$