NEWS
author paulson
Tue Aug 18 10:27:14 1998 +0200 (1998-08-18)
changeset 5332 cd53e59688a8
parent 5308 3ca4da83012c
child 5363 0cf15843b82f
permissions -rw-r--r--
ZF.thy
     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   Now rew can involve either definitions or equalities (either == or =).
   227 
   228 *** ZF ***
   229 
   230 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   231   only the theorems proved on ZF.ML;
   232 
   233 * ZF INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name
   234   was misleading).  The rule and 'sym RS equals0E' are now in the default
   235   claset, giving automatic disjointness reasoning but breaking a few old 
   236   proofs.
   237 
   238 * ZF/Update: new theory of function updates
   239     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   240   may also be iterated as in f(a:=b,c:=d,...);
   241 
   242 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   243 
   244 * calling (stac rew i) now fails if "rew" has no effect on the goal
   245   [previously, this check worked only if the rewrite rule was unconditional]
   246   Now rew can involve either definitions or equalities (either == or =).
   247 
   248 * case_tac provided for compatibility with HOL
   249     (like the old excluded_middle_tac, but with subgoals swapped)
   250 
   251 
   252 *** Internal programming interfaces ***
   253 
   254 * Pure: several new basic modules made available for general use, see
   255 also src/Pure/README;
   256 
   257 * improved the theory data mechanism to support encapsulation (data
   258 kind name replaced by private Object.kind, acting as authorization
   259 key); new type-safe user interface via functor TheoryDataFun;
   260 
   261 * removed global_names compatibility flag -- all theory declarations
   262 are qualified by default;
   263 
   264 * module Pure/Syntax now offers quote / antiquote translation
   265 functions (useful for Hoare logic etc. with implicit dependencies);
   266 
   267 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   268 cterm -> thm;
   269 
   270 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   271 subgoal;
   272 
   273 * Display.print_goals function moved to Locale.print_goals;
   274 
   275 
   276 
   277 New in Isabelle98 (January 1998)
   278 --------------------------------
   279 
   280 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   281 
   282 * changed lexical syntax of terms / types: dots made part of long
   283 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   284 
   285 * simpset (and claset) reference variable replaced by functions
   286 simpset / simpset_ref;
   287 
   288 * no longer supports theory aliases (via merge) and non-trivial
   289 implicit merge of thms' signatures;
   290 
   291 * most internal names of constants changed due to qualified names;
   292 
   293 * changed Pure/Sequence interface (see Pure/seq.ML);
   294 
   295 
   296 *** General Changes ***
   297 
   298 * hierachically structured name spaces (for consts, types, axms, thms
   299 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   300 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   301 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   302 long_names for fully qualified output names; NOTE: ML programs
   303 (special tactics, packages etc.) referring to internal names may have
   304 to be adapted to cope with fully qualified names; in case of severe
   305 backward campatibility problems try setting 'global_names' at compile
   306 time to have enrything declared within a flat name space; one may also
   307 fine tune name declarations in theories via the 'global' and 'local'
   308 section;
   309 
   310 * reimplemented the implicit simpset and claset using the new anytype
   311 data filed in signatures; references simpset:simpset ref etc. are
   312 replaced by functions simpset:unit->simpset and
   313 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   314 to patch your ML files accordingly;
   315 
   316 * HTML output now includes theory graph data for display with Java
   317 applet or isatool browser; data generated automatically via isatool
   318 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   319 
   320 * defs may now be conditional; improved rewrite_goals_tac to handle
   321 conditional equations;
   322 
   323 * defs now admits additional type arguments, using TYPE('a) syntax;
   324 
   325 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   326 creates a new theory node; implicit merge of thms' signatures is
   327 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   328 transfer:theory->thm->thm in (rare) cases;
   329 
   330 * improved handling of draft signatures / theories; draft thms (and
   331 ctyps, cterms) are automatically promoted to real ones;
   332 
   333 * slightly changed interfaces for oracles: admit many per theory, named
   334 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   335 
   336 * print_goals: optional output of const types (set show_consts and
   337 show_types);
   338 
   339 * improved output of warnings (###) and errors (***);
   340 
   341 * subgoal_tac displays a warning if the new subgoal has type variables;
   342 
   343 * removed old README and Makefiles;
   344 
   345 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   346 
   347 * removed obsolete init_pps and init_database;
   348 
   349 * deleted the obsolete tactical STATE, which was declared by
   350     fun STATE tacfun st = tacfun st st;
   351 
   352 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   353 (which abbreviates $HOME);
   354 
   355 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   356 use isatool fixseq to adapt your ML programs (this works for fully
   357 qualified references to the Sequence structure only!);
   358 
   359 * use_thy no longer requires writable current directory; it always
   360 reloads .ML *and* .thy file, if either one is out of date;
   361 
   362 
   363 *** Classical Reasoner ***
   364 
   365 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   366 tactics that use classical reasoning to simplify a subgoal without
   367 splitting it into several subgoals;
   368 
   369 * Safe_tac: like safe_tac but uses the default claset;
   370 
   371 
   372 *** Simplifier ***
   373 
   374 * added simplification meta rules:
   375     (asm_)(full_)simplify: simpset -> thm -> thm;
   376 
   377 * simplifier.ML no longer part of Pure -- has to be loaded by object
   378 logics (again);
   379 
   380 * added prems argument to simplification procedures;
   381 
   382 * HOL, FOL, ZF: added infix function `addsplits':
   383   instead of `<simpset> setloop (split_tac <thms>)'
   384   you can simply write `<simpset> addsplits <thms>'
   385 
   386 
   387 *** Syntax ***
   388 
   389 * TYPE('a) syntax for type reflection terms;
   390 
   391 * no longer handles consts with name "" -- declare as 'syntax' instead;
   392 
   393 * pretty printer: changed order of mixfix annotation preference (again!);
   394 
   395 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   396 
   397 
   398 *** HOL ***
   399 
   400 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   401   with `addloop' of the simplifier to faciliate case splitting in premises.
   402 
   403 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   404 
   405 * HOL/Auth: new protocol proofs including some for the Internet
   406   protocol TLS;
   407 
   408 * HOL/Map: new theory of `maps' a la VDM;
   409 
   410 * HOL/simplifier: simplification procedures nat_cancel_sums for
   411 cancelling out common nat summands from =, <, <= (in)equalities, or
   412 differences; simplification procedures nat_cancel_factor for
   413 cancelling common factor from =, <, <= (in)equalities over natural
   414 sums; nat_cancel contains both kinds of procedures, it is installed by
   415 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   416 
   417 * HOL/simplifier: terms of the form
   418   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   419   are rewritten to
   420   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   421   and those of the form
   422   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   423   are rewritten to
   424   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   425 
   426 * HOL/datatype
   427   Each datatype `t' now comes with a theorem `split_t_case' of the form
   428 
   429   P(t_case f1 ... fn x) =
   430      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   431         ...
   432        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   433      )
   434 
   435   and a theorem `split_t_case_asm' of the form
   436 
   437   P(t_case f1 ... fn x) =
   438     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   439         ...
   440        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   441      )
   442   which can be added to a simpset via `addsplits'. The existing theorems
   443   expand_list_case and expand_option_case have been renamed to
   444   split_list_case and split_option_case.
   445 
   446 * HOL/Arithmetic:
   447   - `pred n' is automatically converted to `n-1'.
   448     Users are strongly encouraged not to use `pred' any longer,
   449     because it will disappear altogether at some point.
   450   - Users are strongly encouraged to write "0 < n" rather than
   451     "n ~= 0". Theorems and proof tools have been modified towards this
   452     `standard'.
   453 
   454 * HOL/Lists:
   455   the function "set_of_list" has been renamed "set" (and its theorems too);
   456   the function "nth" now takes its arguments in the reverse order and
   457   has acquired the infix notation "!" as in "xs!n".
   458 
   459 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   460 
   461 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   462   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   463 
   464 * HOL/record: extensible records with schematic structural subtyping
   465 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   466 still lacks various theorems and concrete record syntax;
   467 
   468 
   469 *** HOLCF ***
   470 
   471 * removed "axioms" and "generated by" sections;
   472 
   473 * replaced "ops" section by extended "consts" section, which is capable of
   474   handling the continuous function space "->" directly;
   475 
   476 * domain package:
   477   . proves theorems immediately and stores them in the theory,
   478   . creates hierachical name space,
   479   . now uses normal mixfix annotations (instead of cinfix...),
   480   . minor changes to some names and values (for consistency),
   481   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   482   . separator between mutual domain defs: changed "," to "and",
   483   . improved handling of sort constraints;  now they have to
   484     appear on the left-hand side of the equations only;
   485 
   486 * fixed LAM <x,y,zs>.b syntax;
   487 
   488 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   489 adm (%x. P (t x)), where P is chainfinite and t continuous;
   490 
   491 
   492 *** FOL and ZF ***
   493 
   494 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   495   with `addloop' of the simplifier to faciliate case splitting in premises.
   496 
   497 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   498 in HOL, they strip ALL and --> from proved theorems;
   499 
   500 
   501 
   502 New in Isabelle94-8 (May 1997)
   503 ------------------------------
   504 
   505 *** General Changes ***
   506 
   507 * new utilities to build / run / maintain Isabelle etc. (in parts
   508 still somewhat experimental); old Makefiles etc. still functional;
   509 
   510 * new 'Isabelle System Manual';
   511 
   512 * INSTALL text, together with ./configure and ./build scripts;
   513 
   514 * reimplemented type inference for greater efficiency, better error
   515 messages and clean internal interface;
   516 
   517 * prlim command for dealing with lots of subgoals (an easier way of
   518 setting goals_limit);
   519 
   520 
   521 *** Syntax ***
   522 
   523 * supports alternative (named) syntax tables (parser and pretty
   524 printer); internal interface is provided by add_modesyntax(_i);
   525 
   526 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   527 be used in conjunction with the Isabelle symbol font; uses the
   528 "symbols" syntax table;
   529 
   530 * added token_translation interface (may translate name tokens in
   531 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   532 the current print_mode); IMPORTANT: user print translation functions
   533 are responsible for marking newly introduced bounds
   534 (Syntax.mark_boundT);
   535 
   536 * token translations for modes "xterm" and "xterm_color" that display
   537 names in bold, underline etc. or colors (which requires a color
   538 version of xterm);
   539 
   540 * infixes may now be declared with names independent of their syntax;
   541 
   542 * added typed_print_translation (like print_translation, but may
   543 access type of constant);
   544 
   545 
   546 *** Classical Reasoner ***
   547 
   548 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   549 some limitations.  Blast_tac...
   550   + ignores addss, addbefore, addafter; this restriction is intrinsic
   551   + ignores elimination rules that don't have the correct format
   552 	(the conclusion MUST be a formula variable)
   553   + ignores types, which can make HOL proofs fail
   554   + rules must not require higher-order unification, e.g. apply_type in ZF
   555     [message "Function Var's argument not a bound variable" relates to this]
   556   + its proof strategy is more general but can actually be slower
   557 
   558 * substitution with equality assumptions no longer permutes other
   559 assumptions;
   560 
   561 * minor changes in semantics of addafter (now called addaltern); renamed
   562 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   563 (and access functions for it);
   564 
   565 * improved combination of classical reasoner and simplifier: 
   566   + functions for handling clasimpsets
   567   + improvement of addss: now the simplifier is called _after_ the
   568     safe steps.
   569   + safe variant of addss called addSss: uses safe simplifications
   570     _during_ the safe steps. It is more complete as it allows multiple 
   571     instantiations of unknowns (e.g. with slow_tac).
   572 
   573 *** Simplifier ***
   574 
   575 * added interface for simplification procedures (functions that
   576 produce *proven* rewrite rules on the fly, depending on current
   577 redex);
   578 
   579 * ordering on terms as parameter (used for ordered rewriting);
   580 
   581 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   582 
   583 * the solver is now split into a safe and an unsafe part.
   584 This should be invisible for the normal user, except that the
   585 functions setsolver and addsolver have been renamed to setSolver and
   586 addSolver; added safe_asm_full_simp_tac;
   587 
   588 
   589 *** HOL ***
   590 
   591 * a generic induction tactic `induct_tac' which works for all datatypes and
   592 also for type `nat';
   593 
   594 * a generic case distinction tactic `exhaust_tac' which works for all
   595 datatypes and also for type `nat';
   596 
   597 * each datatype comes with a function `size';
   598 
   599 * patterns in case expressions allow tuple patterns as arguments to
   600 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   601 
   602 * primrec now also works with type nat;
   603 
   604 * recdef: a new declaration form, allows general recursive functions to be
   605 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   606 
   607 * the constant for negation has been renamed from "not" to "Not" to
   608 harmonize with FOL, ZF, LK, etc.;
   609 
   610 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   611 infinite lists;
   612 
   613 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   614 
   615 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   616 problems in commutative rings, using axiomatic type classes for + and *;
   617 
   618 * more examples in HOL/MiniML and HOL/Auth;
   619 
   620 * more default rewrite rules for quantifiers, union/intersection;
   621 
   622 * a new constant `arbitrary == @x.False';
   623 
   624 * HOLCF/IOA replaces old HOL/IOA;
   625 
   626 * HOLCF changes: derived all rules and arities 
   627   + axiomatic type classes instead of classes 
   628   + typedef instead of faking type definitions
   629   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   630   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   631   + eliminated the types void, one, tr
   632   + use unit lift and bool lift (with translations) instead of one and tr
   633   + eliminated blift from Lift3.thy (use Def instead of blift)
   634   all eliminated rules are derived as theorems --> no visible changes ;
   635 
   636 
   637 *** ZF ***
   638 
   639 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   640 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   641 as ZF_cs addSIs [equalityI];
   642 
   643 
   644 
   645 New in Isabelle94-7 (November 96)
   646 ---------------------------------
   647 
   648 * allowing negative levels (as offsets) in prlev and choplev;
   649 
   650 * super-linear speedup for large simplifications;
   651 
   652 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   653 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   654 FAIL); can suppress it using the command Delsimps (ex_simps @
   655 all_simps); De Morgan laws are also now included, by default;
   656 
   657 * improved printing of ==>  :  ~:
   658 
   659 * new object-logic "Sequents" adds linear logic, while replacing LK
   660 and Modal (thanks to Sara Kalvala);
   661 
   662 * HOL/Auth: correctness proofs for authentication protocols;
   663 
   664 * HOL: new auto_tac combines rewriting and classical reasoning (many
   665 examples on HOL/Auth);
   666 
   667 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   668 the rewriter and classical reasoner simultaneously;
   669 
   670 * function uresult no longer returns theorems in "standard" format;
   671 regain previous version by: val uresult = standard o uresult;
   672 
   673 
   674 
   675 New in Isabelle94-6
   676 -------------------
   677 
   678 * oracles -- these establish an interface between Isabelle and trusted
   679 external reasoners, which may deliver results as theorems;
   680 
   681 * proof objects (in particular record all uses of oracles);
   682 
   683 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   684 
   685 * "constdefs" section in theory files;
   686 
   687 * "primrec" section (HOL) no longer requires names;
   688 
   689 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   690 
   691 
   692 
   693 New in Isabelle94-5
   694 -------------------
   695 
   696 * reduced space requirements;
   697 
   698 * automatic HTML generation from theories;
   699 
   700 * theory files no longer require "..." (quotes) around most types;
   701 
   702 * new examples, including two proofs of the Church-Rosser theorem;
   703 
   704 * non-curried (1994) version of HOL is no longer distributed;
   705 
   706 
   707 
   708 New in Isabelle94-4
   709 -------------------
   710 
   711 * greatly reduced space requirements;
   712 
   713 * theory files (.thy) no longer require \...\ escapes at line breaks;
   714 
   715 * searchable theorem database (see the section "Retrieving theorems" on 
   716 page 8 of the Reference Manual);
   717 
   718 * new examples, including Grabczewski's monumental case study of the
   719 Axiom of Choice;
   720 
   721 * The previous version of HOL renamed to Old_HOL;
   722 
   723 * The new version of HOL (previously called CHOL) uses a curried syntax 
   724 for functions.  Application looks like f a b instead of f(a,b);
   725 
   726 * Mutually recursive inductive definitions finally work in HOL;
   727 
   728 * In ZF, pattern-matching on tuples is now available in all abstractions and
   729 translates to the operator "split";
   730 
   731 
   732 
   733 New in Isabelle94-3
   734 -------------------
   735 
   736 * new infix operator, addss, allowing the classical reasoner to 
   737 perform simplification at each step of its search.  Example:
   738 	fast_tac (cs addss ss)
   739 
   740 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   741 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   742 look like (a,b) instead of <a,b>;
   743 
   744 * PLEASE NOTE: CHOL will eventually replace HOL!
   745 
   746 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   747 It translates to the operator "split".  A new theory of integers is available;
   748 
   749 * In ZF, integer numerals now denote two's-complement binary integers.
   750 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   751 
   752 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   753 of the Axiom of Choice;
   754 
   755 
   756 
   757 New in Isabelle94-2
   758 -------------------
   759 
   760 * Significantly faster resolution;  
   761 
   762 * the different sections in a .thy file can now be mixed and repeated
   763 freely;
   764 
   765 * Database of theorems for FOL, HOL and ZF.  New
   766 commands including qed, qed_goal and bind_thm store theorems in the database.
   767 
   768 * Simple database queries: return a named theorem (get_thm) or all theorems of
   769 a given theory (thms_of), or find out what theory a theorem was proved in
   770 (theory_of_thm);
   771 
   772 * Bugs fixed in the inductive definition and datatype packages;
   773 
   774 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   775 and HOL_dup_cs obsolete;
   776 
   777 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   778 have been removed;
   779 
   780 * Simpler definition of function space in ZF;
   781 
   782 * new results about cardinal and ordinal arithmetic in ZF;
   783 
   784 * 'subtype' facility in HOL for introducing new types as subsets of existing
   785 types;
   786 
   787 
   788 $Id$