NEWS
author nipkow
Fri Sep 04 13:24:10 1998 +0200 (1998-09-04)
changeset 5428 5a6c4f666a25
parent 5407 b450fea6d70c
child 5475 410172655d64
permissions -rw-r--r--
Function 'upt'
     1 
     2 Isabelle NEWS -- history user-relevant 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: new version of inductive and datatype;
    13 
    14 * HOL: major changes to the inductive and datatype packages;
    15 
    16 * HOL: renamed r^-1 to 'converse' from 'inverse'; `inj_onto' is now
    17 called `inj_on';
    18 
    19 * HOL: removed duplicate thms in Arith:
    20   less_imp_add_less  should be replaced by  trans_less_add1
    21   le_imp_add_le      should be replaced by  trans_le_add1
    22 
    23 * Pure: ML function 'theory_of' replaced by 'theory';
    24 
    25 
    26 *** Proof tools ***
    27 
    28 * Simplifier: Asm_full_simp_tac is now more aggressive.
    29   1. It will sometimes reorient premises if that increases their power to
    30      simplify.
    31   2. It does no longer proceed strictly from left to right but may also
    32      rotate premises to achieve further simplification.
    33   For compatibility reasons there is now Asm_lr_simp_tac which is like the
    34   old Asm_full_simp_tac in that it does not rotate premises.
    35 
    36 * Classical reasoner: wrapper mechanism for the classical reasoner now
    37 allows for selected deletion of wrappers, by introduction of names for
    38 wrapper functionals.  This implies that addbefore, addSbefore,
    39 addaltern, and addSaltern now take a pair (name, tactic) as argument,
    40 and that adding two tactics with the same name overwrites the first
    41 one (emitting a warning).
    42   type wrapper = (int -> tactic) -> (int -> tactic)
    43   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
    44   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
    45   delWrapper, delSWrapper: claset *  string            -> claset
    46   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
    47 
    48 * HOL/split_all_tac is now much faster and fails if there is nothing
    49 to split.  Existing (fragile) proofs may require adaption because the
    50 order and the names of the automatically generated variables have
    51 changed.  split_all_tac has moved within claset() from unsafe wrappers
    52 to safe wrappers, which means that !!-bound variables are split much
    53 more aggressively, and safe_tac and clarify_tac now split such
    54 variables.  If this splitting is not appropriate, use delSWrapper
    55 "split_all_tac".
    56 
    57 * HOL/Simplifier:
    58 
    59  - Rewrite rules for case distinctions can now be added permanently to
    60    the default simpset using Addsplits just like Addsimps. They can be
    61    removed via Delsplits just like Delsimps. Lower-case versions are
    62    also available.
    63 
    64  - The rule split_if is now part of the default simpset. This means
    65    that the simplifier will eliminate all occurrences of if-then-else
    66    in the conclusion of a goal. To prevent this, you can either remove
    67    split_if completely from the default simpset by `Delsplits
    68    [split_if]' or remove it in a specific call of the simplifier using
    69    `... delsplits [split_if]'.  You can also add/delete other case
    70    splitting rules to/from the default simpset: every datatype
    71    generates suitable rules `split_t_case' and `split_t_case_asm'
    72    (where t is the name of the datatype).
    73 
    74 * Classical reasoner - Simplifier combination: new force_tac (and
    75 derivatives Force_tac, force) combines rewriting and classical
    76 reasoning (and whatever other tools) similarly to auto_tac, but is
    77 aimed to solve the given subgoal completely;
    78 
    79 
    80 *** General ***
    81 
    82 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
    83 and `goalw': the theory is no longer needed as an explicit argument -
    84 the current theory context is used; assumptions are no longer returned
    85 at the ML-level unless one of them starts with ==> or !!; it is
    86 recommended to convert to these new commands using isatool fixgoal
    87 (backup your sources first!);
    88 
    89 * new top-level commands 'thm' and 'thms' for retrieving theorems from
    90 the current theory context, and 'theory' to lookup stored theories;
    91 
    92 * new theory section 'nonterminals' for purely syntactic types;
    93 
    94 * new theory section 'setup' for generic ML setup functions
    95 (e.g. package initialization);
    96 
    97 * the distribution now includes Isabelle icons: see
    98 lib/logo/isabelle-{small,tiny}.xpm;
    99 
   100 * isatool install - install binaries with absolute references to
   101 ISABELLE_HOME/bin;
   102 
   103 * print mode 'emacs' reserved for Isamode;
   104 
   105 
   106 *** HOL ***
   107 
   108 * HOL/inductive package reorganized and improved: now supports mutual
   109 definitions such as
   110 
   111   inductive EVEN ODD
   112     intrs
   113       null "0 : EVEN"
   114       oddI "n : EVEN ==> Suc n : ODD"
   115       evenI "n : ODD ==> Suc n : EVEN"
   116 
   117 new theorem list "elims" contains an elimination rule for each of the
   118 recursive sets; inductive definitions now handle disjunctive premises
   119 correctly (also ZF);
   120 
   121 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   122 "mutual_induct" no longer exists - the induction rule is always
   123 contained in "induct";
   124 
   125 
   126 * HOL/datatype package re-implemented and greatly improved: now
   127 supports mutually recursive datatypes such as
   128 
   129   datatype
   130     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   131             | SUM ('a aexp) ('a aexp)
   132             | DIFF ('a aexp) ('a aexp)
   133             | NUM 'a
   134   and
   135     'a bexp = LESS ('a aexp) ('a aexp)
   136             | AND ('a bexp) ('a bexp)
   137             | OR ('a bexp) ('a bexp)
   138 
   139 as well as indirectly recursive datatypes such as
   140 
   141   datatype
   142     ('a, 'b) term = Var 'a
   143                   | App 'b ((('a, 'b) term) list)
   144 
   145 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   146 induction on mutually / indirectly recursive datatypes.
   147 
   148 Primrec equations are now stored in theory and can be accessed via
   149 <function_name>.simps.
   150 
   151 INCOMPATIBILITIES:
   152 
   153   - Theories using datatypes must now have theory Datatype as an
   154     ancestor.
   155   - The specific <typename>.induct_tac no longer exists - use the
   156     generic induct_tac instead.
   157   - natE has been renamed to nat.exhaust - use exhaust_tac
   158     instead of res_inst_tac ... natE. Note that the variable
   159     names in nat.exhaust differ from the names in natE, this
   160     may cause some "fragile" proofs to fail.
   161   - The theorems split_<typename>_case and split_<typename>_case_asm
   162     have been renamed to <typename>.split and <typename>.split_asm.
   163   - Since default sorts of type variables are now handled correctly,
   164     some datatype definitions may have to be annotated with explicit
   165     sort constraints.
   166   - Primrec definitions no longer require function name and type
   167     of recursive argument.
   168 
   169 Consider using isatool fixdatatype to adapt your theories and proof
   170 scripts to the new package (backup your sources first!).
   171 
   172 
   173 * HOL/record package: now includes concrete syntax for record types,
   174 terms, updates; still lacks important theorems, like surjective
   175 pairing and split;
   176 
   177 * reorganized the main HOL image: HOL/Integ and String loaded by
   178 default; theory Main includes everything;
   179 
   180 * added option_map_eq_Some to the default simpset claset;
   181 
   182 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   183 
   184 * many new identities for unions, intersections, set difference, etc.;
   185 
   186 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   187 called split_if, split_split, split_sum_case and split_nat_case (to go
   188 with add/delsplits);
   189 
   190 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   191 (?x::unit) = (); this is made part of the default simpset, which COULD
   192 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   193 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   194 unit_abs_eta_conv is added in order to counter the effect of
   195 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   196 %u.f();
   197 
   198 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   199 makes more sense);
   200 
   201 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name was misleading);
   202 
   203 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   204 to 'converse' from 'inverse' (for compatibility with ZF and some
   205 literature);
   206 
   207 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   208 the well-founded relation;
   209 
   210 * HOL/Update: new theory of function updates:
   211     f(a:=b) == %x. if x=a then b else f x
   212 may also be iterated as in f(a:=b,c:=d,...);
   213 
   214 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   215 
   216 * HOL/List:
   217   - new function list_update written xs[i:=v] that updates the i-th
   218     list position. May also be iterated as in xs[i:=a,j:=b,...].
   219   - new function `upt' written [i..j(] which generates the list
   220     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   221     bound write [i..j], which is a shorthand for [i..j+1(].
   222   - new lexicographic orderings and corresponding wellfoundedness theorems.
   223 
   224 * HOL/Arith:
   225   - removed 'pred' (predecessor) function;
   226   - generalized some theorems about n-1;
   227   - many new laws about "div" and "mod";
   228   - new laws about greatest common divisors (see theory ex/Primes);
   229 
   230 * HOL/Relation: renamed the relational operator r^-1 "converse"
   231 instead of "inverse";
   232 
   233 * directory HOL/Real: a construction of the reals using Dedekind cuts
   234 (not included by default);
   235 
   236 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   237 
   238 * calling (stac rew i) now fails if "rew" has no effect on the goal
   239   [previously, this check worked only if the rewrite rule was unconditional]
   240   Now rew can involve either definitions or equalities (either == or =).
   241 
   242 
   243 *** ZF ***
   244 
   245 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   246   only the theorems proved on ZF.ML;
   247 
   248 * ZF INCOMPATIBILITY: rule `equals0D' is now called `equals0E' (the old name
   249   was misleading).  The rule and 'sym RS equals0E' are now in the default
   250   claset, giving automatic disjointness reasoning but breaking a few old 
   251   proofs.
   252 
   253 * ZF/Update: new theory of function updates
   254     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   255   may also be iterated as in f(a:=b,c:=d,...);
   256 
   257 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   258 
   259 * calling (stac rew i) now fails if "rew" has no effect on the goal
   260   [previously, this check worked only if the rewrite rule was unconditional]
   261   Now rew can involve either definitions or equalities (either == or =).
   262 
   263 * case_tac provided for compatibility with HOL
   264     (like the old excluded_middle_tac, but with subgoals swapped)
   265 
   266 
   267 *** Internal programming interfaces ***
   268 
   269 * Pure: several new basic modules made available for general use, see
   270 also src/Pure/README;
   271 
   272 * improved the theory data mechanism to support encapsulation (data
   273 kind name replaced by private Object.kind, acting as authorization
   274 key); new type-safe user interface via functor TheoryDataFun; generic
   275 print_data function becomes basically useless;
   276 
   277 * removed global_names compatibility flag -- all theory declarations
   278 are qualified by default;
   279 
   280 * module Pure/Syntax now offers quote / antiquote translation
   281 functions (useful for Hoare logic etc. with implicit dependencies);
   282 see HOL/ex/Antiquote for an example use;
   283 
   284 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   285 cterm -> thm;
   286 
   287 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   288 subgoal;
   289 
   290 * Display.print_goals function moved to Locale.print_goals;
   291 
   292 
   293 
   294 New in Isabelle98 (January 1998)
   295 --------------------------------
   296 
   297 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   298 
   299 * changed lexical syntax of terms / types: dots made part of long
   300 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   301 
   302 * simpset (and claset) reference variable replaced by functions
   303 simpset / simpset_ref;
   304 
   305 * no longer supports theory aliases (via merge) and non-trivial
   306 implicit merge of thms' signatures;
   307 
   308 * most internal names of constants changed due to qualified names;
   309 
   310 * changed Pure/Sequence interface (see Pure/seq.ML);
   311 
   312 
   313 *** General Changes ***
   314 
   315 * hierachically structured name spaces (for consts, types, axms, thms
   316 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   317 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   318 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   319 long_names for fully qualified output names; NOTE: ML programs
   320 (special tactics, packages etc.) referring to internal names may have
   321 to be adapted to cope with fully qualified names; in case of severe
   322 backward campatibility problems try setting 'global_names' at compile
   323 time to have enrything declared within a flat name space; one may also
   324 fine tune name declarations in theories via the 'global' and 'local'
   325 section;
   326 
   327 * reimplemented the implicit simpset and claset using the new anytype
   328 data filed in signatures; references simpset:simpset ref etc. are
   329 replaced by functions simpset:unit->simpset and
   330 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   331 to patch your ML files accordingly;
   332 
   333 * HTML output now includes theory graph data for display with Java
   334 applet or isatool browser; data generated automatically via isatool
   335 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   336 
   337 * defs may now be conditional; improved rewrite_goals_tac to handle
   338 conditional equations;
   339 
   340 * defs now admits additional type arguments, using TYPE('a) syntax;
   341 
   342 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   343 creates a new theory node; implicit merge of thms' signatures is
   344 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   345 transfer:theory->thm->thm in (rare) cases;
   346 
   347 * improved handling of draft signatures / theories; draft thms (and
   348 ctyps, cterms) are automatically promoted to real ones;
   349 
   350 * slightly changed interfaces for oracles: admit many per theory, named
   351 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   352 
   353 * print_goals: optional output of const types (set show_consts and
   354 show_types);
   355 
   356 * improved output of warnings (###) and errors (***);
   357 
   358 * subgoal_tac displays a warning if the new subgoal has type variables;
   359 
   360 * removed old README and Makefiles;
   361 
   362 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   363 
   364 * removed obsolete init_pps and init_database;
   365 
   366 * deleted the obsolete tactical STATE, which was declared by
   367     fun STATE tacfun st = tacfun st st;
   368 
   369 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   370 (which abbreviates $HOME);
   371 
   372 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   373 use isatool fixseq to adapt your ML programs (this works for fully
   374 qualified references to the Sequence structure only!);
   375 
   376 * use_thy no longer requires writable current directory; it always
   377 reloads .ML *and* .thy file, if either one is out of date;
   378 
   379 
   380 *** Classical Reasoner ***
   381 
   382 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   383 tactics that use classical reasoning to simplify a subgoal without
   384 splitting it into several subgoals;
   385 
   386 * Safe_tac: like safe_tac but uses the default claset;
   387 
   388 
   389 *** Simplifier ***
   390 
   391 * added simplification meta rules:
   392     (asm_)(full_)simplify: simpset -> thm -> thm;
   393 
   394 * simplifier.ML no longer part of Pure -- has to be loaded by object
   395 logics (again);
   396 
   397 * added prems argument to simplification procedures;
   398 
   399 * HOL, FOL, ZF: added infix function `addsplits':
   400   instead of `<simpset> setloop (split_tac <thms>)'
   401   you can simply write `<simpset> addsplits <thms>'
   402 
   403 
   404 *** Syntax ***
   405 
   406 * TYPE('a) syntax for type reflection terms;
   407 
   408 * no longer handles consts with name "" -- declare as 'syntax' instead;
   409 
   410 * pretty printer: changed order of mixfix annotation preference (again!);
   411 
   412 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   413 
   414 
   415 *** HOL ***
   416 
   417 * HOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   418   with `addloop' of the simplifier to faciliate case splitting in premises.
   419 
   420 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   421 
   422 * HOL/Auth: new protocol proofs including some for the Internet
   423   protocol TLS;
   424 
   425 * HOL/Map: new theory of `maps' a la VDM;
   426 
   427 * HOL/simplifier: simplification procedures nat_cancel_sums for
   428 cancelling out common nat summands from =, <, <= (in)equalities, or
   429 differences; simplification procedures nat_cancel_factor for
   430 cancelling common factor from =, <, <= (in)equalities over natural
   431 sums; nat_cancel contains both kinds of procedures, it is installed by
   432 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   433 
   434 * HOL/simplifier: terms of the form
   435   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   436   are rewritten to
   437   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   438   and those of the form
   439   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   440   are rewritten to
   441   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   442 
   443 * HOL/datatype
   444   Each datatype `t' now comes with a theorem `split_t_case' of the form
   445 
   446   P(t_case f1 ... fn x) =
   447      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   448         ...
   449        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   450      )
   451 
   452   and a theorem `split_t_case_asm' of the form
   453 
   454   P(t_case f1 ... fn x) =
   455     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   456         ...
   457        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   458      )
   459   which can be added to a simpset via `addsplits'. The existing theorems
   460   expand_list_case and expand_option_case have been renamed to
   461   split_list_case and split_option_case.
   462 
   463 * HOL/Arithmetic:
   464   - `pred n' is automatically converted to `n-1'.
   465     Users are strongly encouraged not to use `pred' any longer,
   466     because it will disappear altogether at some point.
   467   - Users are strongly encouraged to write "0 < n" rather than
   468     "n ~= 0". Theorems and proof tools have been modified towards this
   469     `standard'.
   470 
   471 * HOL/Lists:
   472   the function "set_of_list" has been renamed "set" (and its theorems too);
   473   the function "nth" now takes its arguments in the reverse order and
   474   has acquired the infix notation "!" as in "xs!n".
   475 
   476 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   477 
   478 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   479   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   480 
   481 * HOL/record: extensible records with schematic structural subtyping
   482 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   483 still lacks various theorems and concrete record syntax;
   484 
   485 
   486 *** HOLCF ***
   487 
   488 * removed "axioms" and "generated by" sections;
   489 
   490 * replaced "ops" section by extended "consts" section, which is capable of
   491   handling the continuous function space "->" directly;
   492 
   493 * domain package:
   494   . proves theorems immediately and stores them in the theory,
   495   . creates hierachical name space,
   496   . now uses normal mixfix annotations (instead of cinfix...),
   497   . minor changes to some names and values (for consistency),
   498   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   499   . separator between mutual domain defs: changed "," to "and",
   500   . improved handling of sort constraints;  now they have to
   501     appear on the left-hand side of the equations only;
   502 
   503 * fixed LAM <x,y,zs>.b syntax;
   504 
   505 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   506 adm (%x. P (t x)), where P is chainfinite and t continuous;
   507 
   508 
   509 *** FOL and ZF ***
   510 
   511 * FOL: there is a new splitter `split_asm_tac' that can be used e.g. 
   512   with `addloop' of the simplifier to faciliate case splitting in premises.
   513 
   514 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   515 in HOL, they strip ALL and --> from proved theorems;
   516 
   517 
   518 
   519 New in Isabelle94-8 (May 1997)
   520 ------------------------------
   521 
   522 *** General Changes ***
   523 
   524 * new utilities to build / run / maintain Isabelle etc. (in parts
   525 still somewhat experimental); old Makefiles etc. still functional;
   526 
   527 * new 'Isabelle System Manual';
   528 
   529 * INSTALL text, together with ./configure and ./build scripts;
   530 
   531 * reimplemented type inference for greater efficiency, better error
   532 messages and clean internal interface;
   533 
   534 * prlim command for dealing with lots of subgoals (an easier way of
   535 setting goals_limit);
   536 
   537 
   538 *** Syntax ***
   539 
   540 * supports alternative (named) syntax tables (parser and pretty
   541 printer); internal interface is provided by add_modesyntax(_i);
   542 
   543 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   544 be used in conjunction with the Isabelle symbol font; uses the
   545 "symbols" syntax table;
   546 
   547 * added token_translation interface (may translate name tokens in
   548 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   549 the current print_mode); IMPORTANT: user print translation functions
   550 are responsible for marking newly introduced bounds
   551 (Syntax.mark_boundT);
   552 
   553 * token translations for modes "xterm" and "xterm_color" that display
   554 names in bold, underline etc. or colors (which requires a color
   555 version of xterm);
   556 
   557 * infixes may now be declared with names independent of their syntax;
   558 
   559 * added typed_print_translation (like print_translation, but may
   560 access type of constant);
   561 
   562 
   563 *** Classical Reasoner ***
   564 
   565 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   566 some limitations.  Blast_tac...
   567   + ignores addss, addbefore, addafter; this restriction is intrinsic
   568   + ignores elimination rules that don't have the correct format
   569 	(the conclusion MUST be a formula variable)
   570   + ignores types, which can make HOL proofs fail
   571   + rules must not require higher-order unification, e.g. apply_type in ZF
   572     [message "Function Var's argument not a bound variable" relates to this]
   573   + its proof strategy is more general but can actually be slower
   574 
   575 * substitution with equality assumptions no longer permutes other
   576 assumptions;
   577 
   578 * minor changes in semantics of addafter (now called addaltern); renamed
   579 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   580 (and access functions for it);
   581 
   582 * improved combination of classical reasoner and simplifier: 
   583   + functions for handling clasimpsets
   584   + improvement of addss: now the simplifier is called _after_ the
   585     safe steps.
   586   + safe variant of addss called addSss: uses safe simplifications
   587     _during_ the safe steps. It is more complete as it allows multiple 
   588     instantiations of unknowns (e.g. with slow_tac).
   589 
   590 *** Simplifier ***
   591 
   592 * added interface for simplification procedures (functions that
   593 produce *proven* rewrite rules on the fly, depending on current
   594 redex);
   595 
   596 * ordering on terms as parameter (used for ordered rewriting);
   597 
   598 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   599 
   600 * the solver is now split into a safe and an unsafe part.
   601 This should be invisible for the normal user, except that the
   602 functions setsolver and addsolver have been renamed to setSolver and
   603 addSolver; added safe_asm_full_simp_tac;
   604 
   605 
   606 *** HOL ***
   607 
   608 * a generic induction tactic `induct_tac' which works for all datatypes and
   609 also for type `nat';
   610 
   611 * a generic case distinction tactic `exhaust_tac' which works for all
   612 datatypes and also for type `nat';
   613 
   614 * each datatype comes with a function `size';
   615 
   616 * patterns in case expressions allow tuple patterns as arguments to
   617 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   618 
   619 * primrec now also works with type nat;
   620 
   621 * recdef: a new declaration form, allows general recursive functions to be
   622 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   623 
   624 * the constant for negation has been renamed from "not" to "Not" to
   625 harmonize with FOL, ZF, LK, etc.;
   626 
   627 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   628 infinite lists;
   629 
   630 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   631 
   632 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   633 problems in commutative rings, using axiomatic type classes for + and *;
   634 
   635 * more examples in HOL/MiniML and HOL/Auth;
   636 
   637 * more default rewrite rules for quantifiers, union/intersection;
   638 
   639 * a new constant `arbitrary == @x.False';
   640 
   641 * HOLCF/IOA replaces old HOL/IOA;
   642 
   643 * HOLCF changes: derived all rules and arities 
   644   + axiomatic type classes instead of classes 
   645   + typedef instead of faking type definitions
   646   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   647   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   648   + eliminated the types void, one, tr
   649   + use unit lift and bool lift (with translations) instead of one and tr
   650   + eliminated blift from Lift3.thy (use Def instead of blift)
   651   all eliminated rules are derived as theorems --> no visible changes ;
   652 
   653 
   654 *** ZF ***
   655 
   656 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   657 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   658 as ZF_cs addSIs [equalityI];
   659 
   660 
   661 
   662 New in Isabelle94-7 (November 96)
   663 ---------------------------------
   664 
   665 * allowing negative levels (as offsets) in prlev and choplev;
   666 
   667 * super-linear speedup for large simplifications;
   668 
   669 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   670 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   671 FAIL); can suppress it using the command Delsimps (ex_simps @
   672 all_simps); De Morgan laws are also now included, by default;
   673 
   674 * improved printing of ==>  :  ~:
   675 
   676 * new object-logic "Sequents" adds linear logic, while replacing LK
   677 and Modal (thanks to Sara Kalvala);
   678 
   679 * HOL/Auth: correctness proofs for authentication protocols;
   680 
   681 * HOL: new auto_tac combines rewriting and classical reasoning (many
   682 examples on HOL/Auth);
   683 
   684 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   685 the rewriter and classical reasoner simultaneously;
   686 
   687 * function uresult no longer returns theorems in "standard" format;
   688 regain previous version by: val uresult = standard o uresult;
   689 
   690 
   691 
   692 New in Isabelle94-6
   693 -------------------
   694 
   695 * oracles -- these establish an interface between Isabelle and trusted
   696 external reasoners, which may deliver results as theorems;
   697 
   698 * proof objects (in particular record all uses of oracles);
   699 
   700 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   701 
   702 * "constdefs" section in theory files;
   703 
   704 * "primrec" section (HOL) no longer requires names;
   705 
   706 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   707 
   708 
   709 
   710 New in Isabelle94-5
   711 -------------------
   712 
   713 * reduced space requirements;
   714 
   715 * automatic HTML generation from theories;
   716 
   717 * theory files no longer require "..." (quotes) around most types;
   718 
   719 * new examples, including two proofs of the Church-Rosser theorem;
   720 
   721 * non-curried (1994) version of HOL is no longer distributed;
   722 
   723 
   724 
   725 New in Isabelle94-4
   726 -------------------
   727 
   728 * greatly reduced space requirements;
   729 
   730 * theory files (.thy) no longer require \...\ escapes at line breaks;
   731 
   732 * searchable theorem database (see the section "Retrieving theorems" on 
   733 page 8 of the Reference Manual);
   734 
   735 * new examples, including Grabczewski's monumental case study of the
   736 Axiom of Choice;
   737 
   738 * The previous version of HOL renamed to Old_HOL;
   739 
   740 * The new version of HOL (previously called CHOL) uses a curried syntax 
   741 for functions.  Application looks like f a b instead of f(a,b);
   742 
   743 * Mutually recursive inductive definitions finally work in HOL;
   744 
   745 * In ZF, pattern-matching on tuples is now available in all abstractions and
   746 translates to the operator "split";
   747 
   748 
   749 
   750 New in Isabelle94-3
   751 -------------------
   752 
   753 * new infix operator, addss, allowing the classical reasoner to 
   754 perform simplification at each step of its search.  Example:
   755 	fast_tac (cs addss ss)
   756 
   757 * a new logic, CHOL, the same as HOL, but with a curried syntax 
   758 for functions.  Application looks like f a b instead of f(a,b).  Also pairs 
   759 look like (a,b) instead of <a,b>;
   760 
   761 * PLEASE NOTE: CHOL will eventually replace HOL!
   762 
   763 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   764 It translates to the operator "split".  A new theory of integers is available;
   765 
   766 * In ZF, integer numerals now denote two's-complement binary integers.
   767 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   768 
   769 * Many new examples: I/O automata, Church-Rosser theorem, equivalents 
   770 of the Axiom of Choice;
   771 
   772 
   773 
   774 New in Isabelle94-2
   775 -------------------
   776 
   777 * Significantly faster resolution;  
   778 
   779 * the different sections in a .thy file can now be mixed and repeated
   780 freely;
   781 
   782 * Database of theorems for FOL, HOL and ZF.  New
   783 commands including qed, qed_goal and bind_thm store theorems in the database.
   784 
   785 * Simple database queries: return a named theorem (get_thm) or all theorems of
   786 a given theory (thms_of), or find out what theory a theorem was proved in
   787 (theory_of_thm);
   788 
   789 * Bugs fixed in the inductive definition and datatype packages;
   790 
   791 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   792 and HOL_dup_cs obsolete;
   793 
   794 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   795 have been removed;
   796 
   797 * Simpler definition of function space in ZF;
   798 
   799 * new results about cardinal and ordinal arithmetic in ZF;
   800 
   801 * 'subtype' facility in HOL for introducing new types as subsets of existing
   802 types;
   803 
   804 
   805 $Id$