NEWS
author wenzelm
Fri Mar 19 11:24:00 1999 +0100 (1999-03-19)
changeset 6404 2daaf2943c79
parent 6403 86e9d24f4238
child 6413 b2f2770ef8d9
permissions -rw-r--r--
common qed and end of proofs;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     8 
     9 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    10 complement;
    11 
    12 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    13 
    14 * HOL/typedef: fixed type inference for representing set; type
    15 arguments now have to occur explicitly on the rhs as type constraints;
    16 
    17 * ZF: The con_defs part of an inductive definition may no longer refer
    18 to constants declared in the same theory;
    19 
    20 * HOL, ZF: the function mk_cases, generated by the inductive
    21 definition package, has lost an argument.  To simplify its result, it
    22 uses the default simpset instead of a supplied list of theorems.
    23 
    24 
    25 *** Proof tools ***
    26 
    27 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
    28 decision procedure for linear arithmetic. Currently it is used for
    29 types `nat' and `int' in HOL (see below) but can, should and will be
    30 instantiated for other types and logics as well.
    31 
    32 
    33 *** General ***
    34 
    35 * in locales, the "assumes" and "defines" parts may be omitted if
    36 empty;
    37 
    38 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
    39 long arrows);
    40 
    41 * new print_mode "HTML";
    42 
    43 * path element specification '~~' refers to '$ISABELLE_HOME';
    44 
    45 * new flag show_tags controls display of tags of theorems (which are
    46 basically just comments that may be attached by some tools);
    47 
    48 
    49 *** HOL ***
    50 
    51 * There are now decision procedures for linear arithmetic over nat and
    52 int:
    53 
    54 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
    55 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
    56 are treated as atomic; subformulae not involving type `nat' or `int'
    57 are ignored; quantified subformulae are ignored unless they are
    58 positive universal or negative existential. The tactic has to be
    59 invoked by hand and can be a little bit slow. In particular, the
    60 running time is exponential in the number of occurrences of `min' and
    61 `max', and `-' on `nat'.
    62 
    63 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
    64 (negated) (in)equalities among the premises and the conclusion into
    65 account (i.e. no compound formulae) and does not know about `min' and
    66 `max', and `-' on `nat'. It is fast and is used automatically by the
    67 simplifier.
    68 
    69 NB: At the moment, these decision procedures do not cope with mixed
    70 nat/int formulae where the two parts interact, such as `m < n ==>
    71 int(m) < int(n)'.
    72 
    73 * New bounded quantifier syntax (input only):
    74   ! x < y. P, ! x <= y. P, ? x < y. P, ? x <= y. P
    75 
    76 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
    77 -- avoids syntactic ambiguities and treats state, transition, and
    78 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
    79 changed syntax and (many) tactics;
    80 
    81 * HOL/typedef: fixed type inference for representing set; type
    82 arguments now have to occur explicitly on the rhs as type constraints;
    83 
    84 
    85 *** ZF ***
    86 
    87 * new primrec section allows primitive recursive functions to be given
    88 directly (as in HOL) over datatypes and the natural numbers;
    89 
    90 * new tactics induct_tac and exhaust_tac for induction (or case
    91 analysis) over datatypes and the natural numbers;
    92 
    93 * the datatype declaration of type T now defines the recursor T_rec;
    94 
    95 * simplification automatically does freeness reasoning for datatype
    96 constructors;
    97 
    98 * automatic type-inference, with AddTCs command to insert new
    99 type-checking rules;
   100 
   101 * datatype introduction rules are now added as Safe Introduction rules
   102 to the claset;
   103 
   104 * the syntax "if P then x else y" is now available in addition to
   105 if(P,x,y);
   106 
   107 
   108 *** Internal programming interfaces ***
   109 
   110 * AxClass.axclass_tac lost the theory argument;
   111 
   112 * tuned current_goals_markers semantics: begin / end goal avoids
   113 printing empty lines;
   114 
   115 * removed prs and prs_fn hook, which was broken because it did not
   116 include \n in its semantics, forcing writeln to add one
   117 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   118 string -> unit if you really want to output text without newline;
   119 
   120 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   121 plain output, interface builders may have to enable 'isabelle_font'
   122 mode to get Isabelle font glyphs as before;
   123 
   124 * refined token_translation interface; INCOMPATIBILITY: output length
   125 now of type real instead of int;
   126 
   127 
   128 
   129 New in Isabelle98-1 (October 1998)
   130 ----------------------------------
   131 
   132 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   133 
   134 * several changes of automated proof tools;
   135 
   136 * HOL: major changes to the inductive and datatype packages, including
   137 some minor incompatibilities of theory syntax;
   138 
   139 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   140 called `inj_on';
   141 
   142 * HOL: removed duplicate thms in Arith:
   143   less_imp_add_less  should be replaced by  trans_less_add1
   144   le_imp_add_le      should be replaced by  trans_le_add1
   145 
   146 * HOL: unary minus is now overloaded (new type constraints may be
   147 required);
   148 
   149 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   150 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   151 now taken as an integer constant.
   152 
   153 * Pure: ML function 'theory_of' renamed to 'theory';
   154 
   155 
   156 *** Proof tools ***
   157 
   158 * Simplifier:
   159   1. Asm_full_simp_tac is now more aggressive.
   160      1. It will sometimes reorient premises if that increases their power to
   161         simplify.
   162      2. It does no longer proceed strictly from left to right but may also
   163         rotate premises to achieve further simplification.
   164      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   165      old Asm_full_simp_tac in that it does not rotate premises.
   166   2. The simplifier now knows a little bit about nat-arithmetic.
   167 
   168 * Classical reasoner: wrapper mechanism for the classical reasoner now
   169 allows for selected deletion of wrappers, by introduction of names for
   170 wrapper functionals.  This implies that addbefore, addSbefore,
   171 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   172 and that adding two tactics with the same name overwrites the first
   173 one (emitting a warning).
   174   type wrapper = (int -> tactic) -> (int -> tactic)
   175   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   176   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   177   delWrapper, delSWrapper: claset *  string            -> claset
   178   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   179 
   180 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   181 semantics; addbefore now affects only the unsafe part of step_tac
   182 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   183 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   184 by Force_tac;
   185 
   186 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   187 compWrapper; added safe wrapper (and access functions for it);
   188 
   189 * HOL/split_all_tac is now much faster and fails if there is nothing
   190 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   191 and the names of the automatically generated variables have changed.
   192 split_all_tac has moved within claset() from unsafe wrappers to safe
   193 wrappers, which means that !!-bound variables are split much more
   194 aggressively, and safe_tac and clarify_tac now split such variables.
   195 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   196 Note: the same holds for record_split_tac, which does the job of
   197 split_all_tac for record fields.
   198 
   199 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   200 permanently to the default simpset using Addsplits just like
   201 Addsimps. They can be removed via Delsplits just like
   202 Delsimps. Lower-case versions are also available.
   203 
   204 * HOL/Simplifier: The rule split_if is now part of the default
   205 simpset. This means that the simplifier will eliminate all occurrences
   206 of if-then-else in the conclusion of a goal. To prevent this, you can
   207 either remove split_if completely from the default simpset by
   208 `Delsplits [split_if]' or remove it in a specific call of the
   209 simplifier using `... delsplits [split_if]'.  You can also add/delete
   210 other case splitting rules to/from the default simpset: every datatype
   211 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   212 t is the name of the datatype).
   213 
   214 * Classical reasoner / Simplifier combination: new force_tac (and
   215 derivatives Force_tac, force) combines rewriting and classical
   216 reasoning (and whatever other tools) similarly to auto_tac, but is
   217 aimed to solve the given subgoal completely.
   218 
   219 
   220 *** General ***
   221 
   222 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   223 and `goalw': the theory is no longer needed as an explicit argument -
   224 the current theory context is used; assumptions are no longer returned
   225 at the ML-level unless one of them starts with ==> or !!; it is
   226 recommended to convert to these new commands using isatool fixgoal
   227 (backup your sources first!);
   228 
   229 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   230 the current theory context, and 'theory' to lookup stored theories;
   231 
   232 * new theory section 'locale' for declaring constants, assumptions and
   233 definitions that have local scope;
   234 
   235 * new theory section 'nonterminals' for purely syntactic types;
   236 
   237 * new theory section 'setup' for generic ML setup functions
   238 (e.g. package initialization);
   239 
   240 * the distribution now includes Isabelle icons: see
   241 lib/logo/isabelle-{small,tiny}.xpm;
   242 
   243 * isatool install - install binaries with absolute references to
   244 ISABELLE_HOME/bin;
   245 
   246 * isatool logo -- create instances of the Isabelle logo (as EPS);
   247 
   248 * print mode 'emacs' reserved for Isamode;
   249 
   250 * support multiple print (ast) translations per constant name;
   251 
   252 
   253 *** HOL ***
   254 
   255 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   256 
   257 * HOL/inductive package reorganized and improved: now supports mutual
   258 definitions such as
   259 
   260   inductive EVEN ODD
   261     intrs
   262       null "0 : EVEN"
   263       oddI "n : EVEN ==> Suc n : ODD"
   264       evenI "n : ODD ==> Suc n : EVEN"
   265 
   266 new theorem list "elims" contains an elimination rule for each of the
   267 recursive sets; inductive definitions now handle disjunctive premises
   268 correctly (also ZF);
   269 
   270 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   271 "mutual_induct" no longer exists - the induction rule is always
   272 contained in "induct";
   273 
   274 
   275 * HOL/datatype package re-implemented and greatly improved: now
   276 supports mutually recursive datatypes such as
   277 
   278   datatype
   279     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   280             | SUM ('a aexp) ('a aexp)
   281             | DIFF ('a aexp) ('a aexp)
   282             | NUM 'a
   283   and
   284     'a bexp = LESS ('a aexp) ('a aexp)
   285             | AND ('a bexp) ('a bexp)
   286             | OR ('a bexp) ('a bexp)
   287 
   288 as well as indirectly recursive datatypes such as
   289 
   290   datatype
   291     ('a, 'b) term = Var 'a
   292                   | App 'b ((('a, 'b) term) list)
   293 
   294 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   295 induction on mutually / indirectly recursive datatypes.
   296 
   297 Primrec equations are now stored in theory and can be accessed via
   298 <function_name>.simps.
   299 
   300 INCOMPATIBILITIES:
   301 
   302   - Theories using datatypes must now have theory Datatype as an
   303     ancestor.
   304   - The specific <typename>.induct_tac no longer exists - use the
   305     generic induct_tac instead.
   306   - natE has been renamed to nat.exhaust - use exhaust_tac
   307     instead of res_inst_tac ... natE. Note that the variable
   308     names in nat.exhaust differ from the names in natE, this
   309     may cause some "fragile" proofs to fail.
   310   - The theorems split_<typename>_case and split_<typename>_case_asm
   311     have been renamed to <typename>.split and <typename>.split_asm.
   312   - Since default sorts of type variables are now handled correctly,
   313     some datatype definitions may have to be annotated with explicit
   314     sort constraints.
   315   - Primrec definitions no longer require function name and type
   316     of recursive argument.
   317 
   318 Consider using isatool fixdatatype to adapt your theories and proof
   319 scripts to the new package (backup your sources first!).
   320 
   321 
   322 * HOL/record package: considerably improved implementation; now
   323 includes concrete syntax for record types, terms, updates; theorems
   324 for surjective pairing and splitting !!-bound record variables; proof
   325 support is as follows:
   326 
   327   1) standard conversions (selectors or updates applied to record
   328 constructor terms) are part of the standard simpset;
   329 
   330   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   331 made part of standard simpset and claset via addIffs;
   332 
   333   3) a tactic for record field splitting (record_split_tac) is part of
   334 the standard claset (addSWrapper);
   335 
   336 To get a better idea about these rules you may retrieve them via
   337 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   338 the name of your record type.
   339 
   340 The split tactic 3) conceptually simplifies by the following rule:
   341 
   342   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   343 
   344 Thus any record variable that is bound by meta-all will automatically
   345 blow up into some record constructor term, consequently the
   346 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   347 solve record problems automatically.
   348 
   349 
   350 * reorganized the main HOL image: HOL/Integ and String loaded by
   351 default; theory Main includes everything;
   352 
   353 * automatic simplification of integer sums and comparisons, using cancellation;
   354 
   355 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   356 
   357 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   358 
   359 * many new identities for unions, intersections, set difference, etc.;
   360 
   361 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   362 called split_if, split_split, split_sum_case and split_nat_case (to go
   363 with add/delsplits);
   364 
   365 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   366 (?x::unit) = (); this is made part of the default simpset, which COULD
   367 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   368 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   369 unit_abs_eta_conv is added in order to counter the effect of
   370 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   371 %u.f();
   372 
   373 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   374 makes more sense);
   375 
   376 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   377   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   378   disjointness reasoning but breaking a few old proofs.
   379 
   380 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   381 to 'converse' from 'inverse' (for compatibility with ZF and some
   382 literature);
   383 
   384 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   385 the well-founded relation;
   386 
   387 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   388     Compl A.  The "Compl" syntax remains available as input syntax for this
   389     release ONLY.
   390 
   391 * HOL/Update: new theory of function updates:
   392     f(a:=b) == %x. if x=a then b else f x
   393 may also be iterated as in f(a:=b,c:=d,...);
   394 
   395 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   396 
   397 * HOL/List:
   398   - new function list_update written xs[i:=v] that updates the i-th
   399     list position. May also be iterated as in xs[i:=a,j:=b,...].
   400   - new function `upt' written [i..j(] which generates the list
   401     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   402     bound write [i..j], which is a shorthand for [i..j+1(].
   403   - new lexicographic orderings and corresponding wellfoundedness theorems.
   404 
   405 * HOL/Arith:
   406   - removed 'pred' (predecessor) function;
   407   - generalized some theorems about n-1;
   408   - many new laws about "div" and "mod";
   409   - new laws about greatest common divisors (see theory ex/Primes);
   410 
   411 * HOL/Relation: renamed the relational operator r^-1 "converse"
   412 instead of "inverse";
   413 
   414 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   415   of the multiset ordering;
   416 
   417 * directory HOL/Real: a construction of the reals using Dedekind cuts
   418   (not included by default);
   419 
   420 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   421 
   422 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   423   programs, i.e. different program variables may have different types.
   424 
   425 * calling (stac rew i) now fails if "rew" has no effect on the goal
   426   [previously, this check worked only if the rewrite rule was unconditional]
   427   Now rew can involve either definitions or equalities (either == or =).
   428 
   429 
   430 *** ZF ***
   431 
   432 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   433   only the theorems proved on ZF.ML;
   434 
   435 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   436   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   437   disjointness reasoning but breaking a few old proofs.
   438 
   439 * ZF/Update: new theory of function updates
   440     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   441   may also be iterated as in f(a:=b,c:=d,...);
   442 
   443 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   444 
   445 * calling (stac rew i) now fails if "rew" has no effect on the goal
   446   [previously, this check worked only if the rewrite rule was unconditional]
   447   Now rew can involve either definitions or equalities (either == or =).
   448 
   449 * case_tac provided for compatibility with HOL
   450     (like the old excluded_middle_tac, but with subgoals swapped)
   451 
   452 
   453 *** Internal programming interfaces ***
   454 
   455 * Pure: several new basic modules made available for general use, see
   456 also src/Pure/README;
   457 
   458 * improved the theory data mechanism to support encapsulation (data
   459 kind name replaced by private Object.kind, acting as authorization
   460 key); new type-safe user interface via functor TheoryDataFun; generic
   461 print_data function becomes basically useless;
   462 
   463 * removed global_names compatibility flag -- all theory declarations
   464 are qualified by default;
   465 
   466 * module Pure/Syntax now offers quote / antiquote translation
   467 functions (useful for Hoare logic etc. with implicit dependencies);
   468 see HOL/ex/Antiquote for an example use;
   469 
   470 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   471 cterm -> thm;
   472 
   473 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   474 subgoal;
   475 
   476 * Display.print_goals function moved to Locale.print_goals;
   477 
   478 * standard print function for goals supports current_goals_markers
   479 variable for marking begin of proof, end of proof, start of goal; the
   480 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   481 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   482 for example;
   483 
   484 
   485 
   486 New in Isabelle98 (January 1998)
   487 --------------------------------
   488 
   489 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   490 
   491 * changed lexical syntax of terms / types: dots made part of long
   492 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   493 
   494 * simpset (and claset) reference variable replaced by functions
   495 simpset / simpset_ref;
   496 
   497 * no longer supports theory aliases (via merge) and non-trivial
   498 implicit merge of thms' signatures;
   499 
   500 * most internal names of constants changed due to qualified names;
   501 
   502 * changed Pure/Sequence interface (see Pure/seq.ML);
   503 
   504 
   505 *** General Changes ***
   506 
   507 * hierachically structured name spaces (for consts, types, axms, thms
   508 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   509 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   510 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   511 long_names for fully qualified output names; NOTE: ML programs
   512 (special tactics, packages etc.) referring to internal names may have
   513 to be adapted to cope with fully qualified names; in case of severe
   514 backward campatibility problems try setting 'global_names' at compile
   515 time to have enrything declared within a flat name space; one may also
   516 fine tune name declarations in theories via the 'global' and 'local'
   517 section;
   518 
   519 * reimplemented the implicit simpset and claset using the new anytype
   520 data filed in signatures; references simpset:simpset ref etc. are
   521 replaced by functions simpset:unit->simpset and
   522 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   523 to patch your ML files accordingly;
   524 
   525 * HTML output now includes theory graph data for display with Java
   526 applet or isatool browser; data generated automatically via isatool
   527 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   528 
   529 * defs may now be conditional; improved rewrite_goals_tac to handle
   530 conditional equations;
   531 
   532 * defs now admits additional type arguments, using TYPE('a) syntax;
   533 
   534 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   535 creates a new theory node; implicit merge of thms' signatures is
   536 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   537 transfer:theory->thm->thm in (rare) cases;
   538 
   539 * improved handling of draft signatures / theories; draft thms (and
   540 ctyps, cterms) are automatically promoted to real ones;
   541 
   542 * slightly changed interfaces for oracles: admit many per theory, named
   543 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   544 
   545 * print_goals: optional output of const types (set show_consts and
   546 show_types);
   547 
   548 * improved output of warnings (###) and errors (***);
   549 
   550 * subgoal_tac displays a warning if the new subgoal has type variables;
   551 
   552 * removed old README and Makefiles;
   553 
   554 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   555 
   556 * removed obsolete init_pps and init_database;
   557 
   558 * deleted the obsolete tactical STATE, which was declared by
   559     fun STATE tacfun st = tacfun st st;
   560 
   561 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   562 (which abbreviates $HOME);
   563 
   564 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   565 use isatool fixseq to adapt your ML programs (this works for fully
   566 qualified references to the Sequence structure only!);
   567 
   568 * use_thy no longer requires writable current directory; it always
   569 reloads .ML *and* .thy file, if either one is out of date;
   570 
   571 
   572 *** Classical Reasoner ***
   573 
   574 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   575 tactics that use classical reasoning to simplify a subgoal without
   576 splitting it into several subgoals;
   577 
   578 * Safe_tac: like safe_tac but uses the default claset;
   579 
   580 
   581 *** Simplifier ***
   582 
   583 * added simplification meta rules:
   584     (asm_)(full_)simplify: simpset -> thm -> thm;
   585 
   586 * simplifier.ML no longer part of Pure -- has to be loaded by object
   587 logics (again);
   588 
   589 * added prems argument to simplification procedures;
   590 
   591 * HOL, FOL, ZF: added infix function `addsplits':
   592   instead of `<simpset> setloop (split_tac <thms>)'
   593   you can simply write `<simpset> addsplits <thms>'
   594 
   595 
   596 *** Syntax ***
   597 
   598 * TYPE('a) syntax for type reflection terms;
   599 
   600 * no longer handles consts with name "" -- declare as 'syntax' instead;
   601 
   602 * pretty printer: changed order of mixfix annotation preference (again!);
   603 
   604 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   605 
   606 
   607 *** HOL ***
   608 
   609 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   610   with `addloop' of the simplifier to faciliate case splitting in premises.
   611 
   612 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   613 
   614 * HOL/Auth: new protocol proofs including some for the Internet
   615   protocol TLS;
   616 
   617 * HOL/Map: new theory of `maps' a la VDM;
   618 
   619 * HOL/simplifier: simplification procedures nat_cancel_sums for
   620 cancelling out common nat summands from =, <, <= (in)equalities, or
   621 differences; simplification procedures nat_cancel_factor for
   622 cancelling common factor from =, <, <= (in)equalities over natural
   623 sums; nat_cancel contains both kinds of procedures, it is installed by
   624 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   625 
   626 * HOL/simplifier: terms of the form
   627   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   628   are rewritten to
   629   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   630   and those of the form
   631   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   632   are rewritten to
   633   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   634 
   635 * HOL/datatype
   636   Each datatype `t' now comes with a theorem `split_t_case' of the form
   637 
   638   P(t_case f1 ... fn x) =
   639      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   640         ...
   641        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   642      )
   643 
   644   and a theorem `split_t_case_asm' of the form
   645 
   646   P(t_case f1 ... fn x) =
   647     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   648         ...
   649        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   650      )
   651   which can be added to a simpset via `addsplits'. The existing theorems
   652   expand_list_case and expand_option_case have been renamed to
   653   split_list_case and split_option_case.
   654 
   655 * HOL/Arithmetic:
   656   - `pred n' is automatically converted to `n-1'.
   657     Users are strongly encouraged not to use `pred' any longer,
   658     because it will disappear altogether at some point.
   659   - Users are strongly encouraged to write "0 < n" rather than
   660     "n ~= 0". Theorems and proof tools have been modified towards this
   661     `standard'.
   662 
   663 * HOL/Lists:
   664   the function "set_of_list" has been renamed "set" (and its theorems too);
   665   the function "nth" now takes its arguments in the reverse order and
   666   has acquired the infix notation "!" as in "xs!n".
   667 
   668 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   669 
   670 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   671   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   672 
   673 * HOL/record: extensible records with schematic structural subtyping
   674 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   675 still lacks various theorems and concrete record syntax;
   676 
   677 
   678 *** HOLCF ***
   679 
   680 * removed "axioms" and "generated by" sections;
   681 
   682 * replaced "ops" section by extended "consts" section, which is capable of
   683   handling the continuous function space "->" directly;
   684 
   685 * domain package:
   686   . proves theorems immediately and stores them in the theory,
   687   . creates hierachical name space,
   688   . now uses normal mixfix annotations (instead of cinfix...),
   689   . minor changes to some names and values (for consistency),
   690   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   691   . separator between mutual domain defs: changed "," to "and",
   692   . improved handling of sort constraints;  now they have to
   693     appear on the left-hand side of the equations only;
   694 
   695 * fixed LAM <x,y,zs>.b syntax;
   696 
   697 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   698 adm (%x. P (t x)), where P is chainfinite and t continuous;
   699 
   700 
   701 *** FOL and ZF ***
   702 
   703 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   704   with `addloop' of the simplifier to faciliate case splitting in premises.
   705 
   706 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   707 in HOL, they strip ALL and --> from proved theorems;
   708 
   709 
   710 
   711 New in Isabelle94-8 (May 1997)
   712 ------------------------------
   713 
   714 *** General Changes ***
   715 
   716 * new utilities to build / run / maintain Isabelle etc. (in parts
   717 still somewhat experimental); old Makefiles etc. still functional;
   718 
   719 * new 'Isabelle System Manual';
   720 
   721 * INSTALL text, together with ./configure and ./build scripts;
   722 
   723 * reimplemented type inference for greater efficiency, better error
   724 messages and clean internal interface;
   725 
   726 * prlim command for dealing with lots of subgoals (an easier way of
   727 setting goals_limit);
   728 
   729 
   730 *** Syntax ***
   731 
   732 * supports alternative (named) syntax tables (parser and pretty
   733 printer); internal interface is provided by add_modesyntax(_i);
   734 
   735 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   736 be used in conjunction with the Isabelle symbol font; uses the
   737 "symbols" syntax table;
   738 
   739 * added token_translation interface (may translate name tokens in
   740 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   741 the current print_mode); IMPORTANT: user print translation functions
   742 are responsible for marking newly introduced bounds
   743 (Syntax.mark_boundT);
   744 
   745 * token translations for modes "xterm" and "xterm_color" that display
   746 names in bold, underline etc. or colors (which requires a color
   747 version of xterm);
   748 
   749 * infixes may now be declared with names independent of their syntax;
   750 
   751 * added typed_print_translation (like print_translation, but may
   752 access type of constant);
   753 
   754 
   755 *** Classical Reasoner ***
   756 
   757 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   758 some limitations.  Blast_tac...
   759   + ignores addss, addbefore, addafter; this restriction is intrinsic
   760   + ignores elimination rules that don't have the correct format
   761         (the conclusion MUST be a formula variable)
   762   + ignores types, which can make HOL proofs fail
   763   + rules must not require higher-order unification, e.g. apply_type in ZF
   764     [message "Function Var's argument not a bound variable" relates to this]
   765   + its proof strategy is more general but can actually be slower
   766 
   767 * substitution with equality assumptions no longer permutes other
   768 assumptions;
   769 
   770 * minor changes in semantics of addafter (now called addaltern); renamed
   771 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   772 (and access functions for it);
   773 
   774 * improved combination of classical reasoner and simplifier:
   775   + functions for handling clasimpsets
   776   + improvement of addss: now the simplifier is called _after_ the
   777     safe steps.
   778   + safe variant of addss called addSss: uses safe simplifications
   779     _during_ the safe steps. It is more complete as it allows multiple
   780     instantiations of unknowns (e.g. with slow_tac).
   781 
   782 *** Simplifier ***
   783 
   784 * added interface for simplification procedures (functions that
   785 produce *proven* rewrite rules on the fly, depending on current
   786 redex);
   787 
   788 * ordering on terms as parameter (used for ordered rewriting);
   789 
   790 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   791 
   792 * the solver is now split into a safe and an unsafe part.
   793 This should be invisible for the normal user, except that the
   794 functions setsolver and addsolver have been renamed to setSolver and
   795 addSolver; added safe_asm_full_simp_tac;
   796 
   797 
   798 *** HOL ***
   799 
   800 * a generic induction tactic `induct_tac' which works for all datatypes and
   801 also for type `nat';
   802 
   803 * a generic case distinction tactic `exhaust_tac' which works for all
   804 datatypes and also for type `nat';
   805 
   806 * each datatype comes with a function `size';
   807 
   808 * patterns in case expressions allow tuple patterns as arguments to
   809 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   810 
   811 * primrec now also works with type nat;
   812 
   813 * recdef: a new declaration form, allows general recursive functions to be
   814 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   815 
   816 * the constant for negation has been renamed from "not" to "Not" to
   817 harmonize with FOL, ZF, LK, etc.;
   818 
   819 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   820 infinite lists;
   821 
   822 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   823 
   824 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   825 problems in commutative rings, using axiomatic type classes for + and *;
   826 
   827 * more examples in HOL/MiniML and HOL/Auth;
   828 
   829 * more default rewrite rules for quantifiers, union/intersection;
   830 
   831 * a new constant `arbitrary == @x.False';
   832 
   833 * HOLCF/IOA replaces old HOL/IOA;
   834 
   835 * HOLCF changes: derived all rules and arities
   836   + axiomatic type classes instead of classes
   837   + typedef instead of faking type definitions
   838   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   839   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   840   + eliminated the types void, one, tr
   841   + use unit lift and bool lift (with translations) instead of one and tr
   842   + eliminated blift from Lift3.thy (use Def instead of blift)
   843   all eliminated rules are derived as theorems --> no visible changes ;
   844 
   845 
   846 *** ZF ***
   847 
   848 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   849 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   850 as ZF_cs addSIs [equalityI];
   851 
   852 
   853 
   854 New in Isabelle94-7 (November 96)
   855 ---------------------------------
   856 
   857 * allowing negative levels (as offsets) in prlev and choplev;
   858 
   859 * super-linear speedup for large simplifications;
   860 
   861 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   862 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   863 FAIL); can suppress it using the command Delsimps (ex_simps @
   864 all_simps); De Morgan laws are also now included, by default;
   865 
   866 * improved printing of ==>  :  ~:
   867 
   868 * new object-logic "Sequents" adds linear logic, while replacing LK
   869 and Modal (thanks to Sara Kalvala);
   870 
   871 * HOL/Auth: correctness proofs for authentication protocols;
   872 
   873 * HOL: new auto_tac combines rewriting and classical reasoning (many
   874 examples on HOL/Auth);
   875 
   876 * HOL: new command AddIffs for declaring theorems of the form P=Q to
   877 the rewriter and classical reasoner simultaneously;
   878 
   879 * function uresult no longer returns theorems in "standard" format;
   880 regain previous version by: val uresult = standard o uresult;
   881 
   882 
   883 
   884 New in Isabelle94-6
   885 -------------------
   886 
   887 * oracles -- these establish an interface between Isabelle and trusted
   888 external reasoners, which may deliver results as theorems;
   889 
   890 * proof objects (in particular record all uses of oracles);
   891 
   892 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
   893 
   894 * "constdefs" section in theory files;
   895 
   896 * "primrec" section (HOL) no longer requires names;
   897 
   898 * internal type "tactic" now simply "thm -> thm Sequence.seq";
   899 
   900 
   901 
   902 New in Isabelle94-5
   903 -------------------
   904 
   905 * reduced space requirements;
   906 
   907 * automatic HTML generation from theories;
   908 
   909 * theory files no longer require "..." (quotes) around most types;
   910 
   911 * new examples, including two proofs of the Church-Rosser theorem;
   912 
   913 * non-curried (1994) version of HOL is no longer distributed;
   914 
   915 
   916 
   917 New in Isabelle94-4
   918 -------------------
   919 
   920 * greatly reduced space requirements;
   921 
   922 * theory files (.thy) no longer require \...\ escapes at line breaks;
   923 
   924 * searchable theorem database (see the section "Retrieving theorems" on
   925 page 8 of the Reference Manual);
   926 
   927 * new examples, including Grabczewski's monumental case study of the
   928 Axiom of Choice;
   929 
   930 * The previous version of HOL renamed to Old_HOL;
   931 
   932 * The new version of HOL (previously called CHOL) uses a curried syntax
   933 for functions.  Application looks like f a b instead of f(a,b);
   934 
   935 * Mutually recursive inductive definitions finally work in HOL;
   936 
   937 * In ZF, pattern-matching on tuples is now available in all abstractions and
   938 translates to the operator "split";
   939 
   940 
   941 
   942 New in Isabelle94-3
   943 -------------------
   944 
   945 * new infix operator, addss, allowing the classical reasoner to
   946 perform simplification at each step of its search.  Example:
   947         fast_tac (cs addss ss)
   948 
   949 * a new logic, CHOL, the same as HOL, but with a curried syntax
   950 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
   951 look like (a,b) instead of <a,b>;
   952 
   953 * PLEASE NOTE: CHOL will eventually replace HOL!
   954 
   955 * In CHOL, pattern-matching on tuples is now available in all abstractions.
   956 It translates to the operator "split".  A new theory of integers is available;
   957 
   958 * In ZF, integer numerals now denote two's-complement binary integers.
   959 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
   960 
   961 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
   962 of the Axiom of Choice;
   963 
   964 
   965 
   966 New in Isabelle94-2
   967 -------------------
   968 
   969 * Significantly faster resolution;
   970 
   971 * the different sections in a .thy file can now be mixed and repeated
   972 freely;
   973 
   974 * Database of theorems for FOL, HOL and ZF.  New
   975 commands including qed, qed_goal and bind_thm store theorems in the database.
   976 
   977 * Simple database queries: return a named theorem (get_thm) or all theorems of
   978 a given theory (thms_of), or find out what theory a theorem was proved in
   979 (theory_of_thm);
   980 
   981 * Bugs fixed in the inductive definition and datatype packages;
   982 
   983 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
   984 and HOL_dup_cs obsolete;
   985 
   986 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
   987 have been removed;
   988 
   989 * Simpler definition of function space in ZF;
   990 
   991 * new results about cardinal and ordinal arithmetic in ZF;
   992 
   993 * 'subtype' facility in HOL for introducing new types as subsets of existing
   994 types;
   995 
   996 
   997 $Id$