NEWS
author nipkow
Mon Aug 23 16:22:23 1999 +0200 (1999-08-23)
changeset 7324 6cb0d0202298
parent 7320 e89fd7d0a624
child 7326 a1555491a966
permissions -rw-r--r--
simplifier flex heads.
     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 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
    11 are no longer simplified.  (This allows the simplifier to unfold recursive
    12 functional programs.)  To restore the old behaviour, declare
    13 
    14     Delcongs [if_weak_cong];
    15 
    16 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    17 complement;
    18 
    19 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    20 
    21 * HOL/typedef: fixed type inference for representing set; type
    22 arguments now have to occur explicitly on the rhs as type constraints;
    23 
    24 * ZF: The con_defs part of an inductive definition may no longer refer
    25 to constants declared in the same theory;
    26 
    27 * HOL, ZF: the function mk_cases, generated by the inductive
    28 definition package, has lost an argument.  To simplify its result, it
    29 uses the default simpset instead of a supplied list of theorems.
    30 
    31 * HOL/List: the constructors of type list are now Nil and Cons;
    32 
    33 
    34 *** Proof tools ***
    35 
    36 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
    37 decision procedure for linear arithmetic. Currently it is used for
    38 types `nat' and `int' in HOL (see below) but can, should and will be
    39 instantiated for other types and logics as well.
    40 
    41 * The simplifier now accepts rewrite rules with flexible heads, eg
    42      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
    43   They are applied like any rule with a non-pattern lhs, i.e. by first-order
    44   matching.
    45 
    46 *** General ***
    47 
    48 * new Isabelle/Isar subsystem provides an alternative to traditional
    49 tactical theorem proving; together with the ProofGeneral/isar user
    50 interface it offers an interactive environment for developing human
    51 readable proof documents (Isar == Intelligible semi-automated
    52 reasoning); see isatool doc isar-ref and
    53 http://isabelle.in.tum.de/Isar/ for more information;
    54 
    55 * native support for Proof General, both for classic Isabelle and
    56 Isabelle/Isar (the latter is slightly better supported and more
    57 robust);
    58 
    59 * Isabelle manuals now also available as PDF;
    60 
    61 * improved browser info generation: better HTML markup (including
    62 colors), graph views in several sizes; isatool usedir now provides a
    63 proper interface for user theories (via -P option);
    64 
    65 * theory loader rewritten from scratch (may not be fully
    66 bug-compatible); old loadpath variable has been replaced by show_path,
    67 add_path, del_path, reset_path functions; new operations such as
    68 update_thy, touch_thy, remove_thy (see also isatool doc ref);
    69 
    70 * improved isatool install: option -k creates KDE application icon,
    71 option -p DIR installs standalone binaries;
    72 
    73 * added ML_PLATFORM setting (useful for cross-platform installations);
    74 more robust handling of platform specific ML images for SML/NJ;
    75 
    76 * path element specification '~~' refers to '$ISABELLE_HOME';
    77 
    78 * in locales, the "assumes" and "defines" parts may be omitted if
    79 empty;
    80 
    81 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
    82 long arrows);
    83 
    84 * new print_mode "HTML";
    85 
    86 * new flag show_tags controls display of tags of theorems (which are
    87 basically just comments that may be attached by some tools);
    88 
    89 * Isamode 2.6 requires patch to accomodate change of Isabelle font
    90 mode and goal output format:
    91 
    92 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
    93 244c244
    94 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
    95 ---
    96 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
    97 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
    98 181c181
    99 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   100 ---
   101 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   102 
   103 
   104 *** HOL ***
   105 
   106 ** HOL arithmetic **
   107 
   108 * There are now decision procedures for linear arithmetic over nat and
   109 int:
   110 
   111 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   112 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   113 are treated as atomic; subformulae not involving type `nat' or `int'
   114 are ignored; quantified subformulae are ignored unless they are
   115 positive universal or negative existential. The tactic has to be
   116 invoked by hand and can be a little bit slow. In particular, the
   117 running time is exponential in the number of occurrences of `min' and
   118 `max', and `-' on `nat'.
   119 
   120 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   121 (negated) (in)equalities among the premises and the conclusion into
   122 account (i.e. no compound formulae) and does not know about `min' and
   123 `max', and `-' on `nat'. It is fast and is used automatically by the
   124 simplifier.
   125 
   126 NB: At the moment, these decision procedures do not cope with mixed
   127 nat/int formulae where the two parts interact, such as `m < n ==>
   128 int(m) < int(n)'.
   129 
   130 * HOL/Numeral provides a generic theory of numerals (encoded
   131 efficiently as bit strings); setup for types nat/int/real is in place;
   132 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   133 int, existing theories and proof scripts may require a few additional
   134 type constraints;
   135 
   136 * integer division and remainder can now be performed on constant
   137 arguments;
   138 
   139 * many properties of integer multiplication, division and remainder
   140 are now available;
   141 
   142 * An interface to the Stanford Validity Checker (SVC) is available through the
   143 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   144 are proved automatically.  SVC must be installed separately, and its results
   145 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   146 invocation of the underlying oracle).  For SVC see
   147   http://agamemnon.stanford.edu/~levitt/vc/index.html
   148 
   149 * IsaMakefile: the HOL-Real target now builds an actual image;
   150 
   151 
   152 ** HOL misc **
   153 
   154 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   155 -- avoids syntactic ambiguities and treats state, transition, and
   156 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   157 changed syntax and (many) tactics;
   158 
   159 * HOL/datatype: Now also handles arbitrarily branching datatypes
   160   (using function types) such as
   161 
   162   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   163 
   164 * HOL/typedef: fixed type inference for representing set; type
   165 arguments now have to occur explicitly on the rhs as type constraints;
   166 
   167 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   168 names rather than an ML expression;
   169 
   170 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   171 supplied later.  Program schemes can be defined, such as
   172     "While B C s = (if B s then While B C (C s) else s)"
   173 where the well-founded relation can be chosen after B and C have been given.
   174 
   175 * HOL/List: the constructors of type list are now Nil and Cons;
   176 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   177 course, ML tools referring to List.list.op # etc. have to be adapted;
   178 
   179 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   180 disabled by default; run isabelle with option -m HOL to get back to
   181 the original Gordon/HOL-style output;
   182 
   183 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   184 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   185 
   186 * HOL basic syntax simplified (more orthogonal): all variants of
   187 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   188 Eps operator is provided as well: "SOME x. P[x]";
   189 
   190 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   191 
   192 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   193 thus available for user theories;
   194 
   195 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   196 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   197 time;
   198 
   199 
   200 *** LK ***
   201 
   202 * the notation <<...>> is now available as a notation for sequences of
   203 formulas;
   204 
   205 * the simplifier is now installed
   206 
   207 * the axiom system has been generalized (thanks to Soren Heilmann) 
   208 
   209 * the classical reasoner now has a default rule database
   210 
   211 
   212 *** ZF ***
   213 
   214 * new primrec section allows primitive recursive functions to be given
   215 directly (as in HOL) over datatypes and the natural numbers;
   216 
   217 * new tactics induct_tac and exhaust_tac for induction (or case
   218 analysis) over datatypes and the natural numbers;
   219 
   220 * the datatype declaration of type T now defines the recursor T_rec;
   221 
   222 * simplification automatically does freeness reasoning for datatype
   223 constructors;
   224 
   225 * automatic type-inference, with AddTCs command to insert new
   226 type-checking rules;
   227 
   228 * datatype introduction rules are now added as Safe Introduction rules
   229 to the claset;
   230 
   231 * the syntax "if P then x else y" is now available in addition to
   232 if(P,x,y);
   233 
   234 
   235 *** Internal programming interfaces ***
   236 
   237 * AxClass.axclass_tac lost the theory argument;
   238 
   239 * tuned current_goals_markers semantics: begin / end goal avoids
   240 printing empty lines;
   241 
   242 * removed prs and prs_fn hook, which was broken because it did not
   243 include \n in its semantics, forcing writeln to add one
   244 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   245 string -> unit if you really want to output text without newline;
   246 
   247 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   248 plain output, interface builders may have to enable 'isabelle_font'
   249 mode to get Isabelle font glyphs as before;
   250 
   251 * refined token_translation interface; INCOMPATIBILITY: output length
   252 now of type real instead of int;
   253 
   254 * theory loader actions may be traced via new ThyInfo.add_hook
   255 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   256 your own database of information attached to *whole* theories -- as
   257 opposed to intra-theory data slots offered via TheoryDataFun;
   258 
   259 
   260 
   261 New in Isabelle98-1 (October 1998)
   262 ----------------------------------
   263 
   264 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   265 
   266 * several changes of automated proof tools;
   267 
   268 * HOL: major changes to the inductive and datatype packages, including
   269 some minor incompatibilities of theory syntax;
   270 
   271 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   272 called `inj_on';
   273 
   274 * HOL: removed duplicate thms in Arith:
   275   less_imp_add_less  should be replaced by  trans_less_add1
   276   le_imp_add_le      should be replaced by  trans_le_add1
   277 
   278 * HOL: unary minus is now overloaded (new type constraints may be
   279 required);
   280 
   281 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   282 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   283 now taken as an integer constant.
   284 
   285 * Pure: ML function 'theory_of' renamed to 'theory';
   286 
   287 
   288 *** Proof tools ***
   289 
   290 * Simplifier:
   291   1. Asm_full_simp_tac is now more aggressive.
   292      1. It will sometimes reorient premises if that increases their power to
   293         simplify.
   294      2. It does no longer proceed strictly from left to right but may also
   295         rotate premises to achieve further simplification.
   296      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   297      old Asm_full_simp_tac in that it does not rotate premises.
   298   2. The simplifier now knows a little bit about nat-arithmetic.
   299 
   300 * Classical reasoner: wrapper mechanism for the classical reasoner now
   301 allows for selected deletion of wrappers, by introduction of names for
   302 wrapper functionals.  This implies that addbefore, addSbefore,
   303 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   304 and that adding two tactics with the same name overwrites the first
   305 one (emitting a warning).
   306   type wrapper = (int -> tactic) -> (int -> tactic)
   307   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   308   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   309   delWrapper, delSWrapper: claset *  string            -> claset
   310   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   311 
   312 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   313 semantics; addbefore now affects only the unsafe part of step_tac
   314 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   315 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   316 by Force_tac;
   317 
   318 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   319 compWrapper; added safe wrapper (and access functions for it);
   320 
   321 * HOL/split_all_tac is now much faster and fails if there is nothing
   322 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   323 and the names of the automatically generated variables have changed.
   324 split_all_tac has moved within claset() from unsafe wrappers to safe
   325 wrappers, which means that !!-bound variables are split much more
   326 aggressively, and safe_tac and clarify_tac now split such variables.
   327 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   328 Note: the same holds for record_split_tac, which does the job of
   329 split_all_tac for record fields.
   330 
   331 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   332 permanently to the default simpset using Addsplits just like
   333 Addsimps. They can be removed via Delsplits just like
   334 Delsimps. Lower-case versions are also available.
   335 
   336 * HOL/Simplifier: The rule split_if is now part of the default
   337 simpset. This means that the simplifier will eliminate all occurrences
   338 of if-then-else in the conclusion of a goal. To prevent this, you can
   339 either remove split_if completely from the default simpset by
   340 `Delsplits [split_if]' or remove it in a specific call of the
   341 simplifier using `... delsplits [split_if]'.  You can also add/delete
   342 other case splitting rules to/from the default simpset: every datatype
   343 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   344 t is the name of the datatype).
   345 
   346 * Classical reasoner / Simplifier combination: new force_tac (and
   347 derivatives Force_tac, force) combines rewriting and classical
   348 reasoning (and whatever other tools) similarly to auto_tac, but is
   349 aimed to solve the given subgoal completely.
   350 
   351 
   352 *** General ***
   353 
   354 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   355 and `goalw': the theory is no longer needed as an explicit argument -
   356 the current theory context is used; assumptions are no longer returned
   357 at the ML-level unless one of them starts with ==> or !!; it is
   358 recommended to convert to these new commands using isatool fixgoal
   359 (backup your sources first!);
   360 
   361 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   362 the current theory context, and 'theory' to lookup stored theories;
   363 
   364 * new theory section 'locale' for declaring constants, assumptions and
   365 definitions that have local scope;
   366 
   367 * new theory section 'nonterminals' for purely syntactic types;
   368 
   369 * new theory section 'setup' for generic ML setup functions
   370 (e.g. package initialization);
   371 
   372 * the distribution now includes Isabelle icons: see
   373 lib/logo/isabelle-{small,tiny}.xpm;
   374 
   375 * isatool install - install binaries with absolute references to
   376 ISABELLE_HOME/bin;
   377 
   378 * isatool logo -- create instances of the Isabelle logo (as EPS);
   379 
   380 * print mode 'emacs' reserved for Isamode;
   381 
   382 * support multiple print (ast) translations per constant name;
   383 
   384 * theorems involving oracles are now printed with a suffixed [!];
   385 
   386 
   387 *** HOL ***
   388 
   389 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   390 
   391 * HOL/inductive package reorganized and improved: now supports mutual
   392 definitions such as
   393 
   394   inductive EVEN ODD
   395     intrs
   396       null "0 : EVEN"
   397       oddI "n : EVEN ==> Suc n : ODD"
   398       evenI "n : ODD ==> Suc n : EVEN"
   399 
   400 new theorem list "elims" contains an elimination rule for each of the
   401 recursive sets; inductive definitions now handle disjunctive premises
   402 correctly (also ZF);
   403 
   404 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   405 "mutual_induct" no longer exists - the induction rule is always
   406 contained in "induct";
   407 
   408 
   409 * HOL/datatype package re-implemented and greatly improved: now
   410 supports mutually recursive datatypes such as
   411 
   412   datatype
   413     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   414             | SUM ('a aexp) ('a aexp)
   415             | DIFF ('a aexp) ('a aexp)
   416             | NUM 'a
   417   and
   418     'a bexp = LESS ('a aexp) ('a aexp)
   419             | AND ('a bexp) ('a bexp)
   420             | OR ('a bexp) ('a bexp)
   421 
   422 as well as indirectly recursive datatypes such as
   423 
   424   datatype
   425     ('a, 'b) term = Var 'a
   426                   | App 'b ((('a, 'b) term) list)
   427 
   428 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   429 induction on mutually / indirectly recursive datatypes.
   430 
   431 Primrec equations are now stored in theory and can be accessed via
   432 <function_name>.simps.
   433 
   434 INCOMPATIBILITIES:
   435 
   436   - Theories using datatypes must now have theory Datatype as an
   437     ancestor.
   438   - The specific <typename>.induct_tac no longer exists - use the
   439     generic induct_tac instead.
   440   - natE has been renamed to nat.exhaust - use exhaust_tac
   441     instead of res_inst_tac ... natE. Note that the variable
   442     names in nat.exhaust differ from the names in natE, this
   443     may cause some "fragile" proofs to fail.
   444   - The theorems split_<typename>_case and split_<typename>_case_asm
   445     have been renamed to <typename>.split and <typename>.split_asm.
   446   - Since default sorts of type variables are now handled correctly,
   447     some datatype definitions may have to be annotated with explicit
   448     sort constraints.
   449   - Primrec definitions no longer require function name and type
   450     of recursive argument.
   451 
   452 Consider using isatool fixdatatype to adapt your theories and proof
   453 scripts to the new package (backup your sources first!).
   454 
   455 
   456 * HOL/record package: considerably improved implementation; now
   457 includes concrete syntax for record types, terms, updates; theorems
   458 for surjective pairing and splitting !!-bound record variables; proof
   459 support is as follows:
   460 
   461   1) standard conversions (selectors or updates applied to record
   462 constructor terms) are part of the standard simpset;
   463 
   464   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   465 made part of standard simpset and claset via addIffs;
   466 
   467   3) a tactic for record field splitting (record_split_tac) is part of
   468 the standard claset (addSWrapper);
   469 
   470 To get a better idea about these rules you may retrieve them via
   471 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   472 the name of your record type.
   473 
   474 The split tactic 3) conceptually simplifies by the following rule:
   475 
   476   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   477 
   478 Thus any record variable that is bound by meta-all will automatically
   479 blow up into some record constructor term, consequently the
   480 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   481 solve record problems automatically.
   482 
   483 
   484 * reorganized the main HOL image: HOL/Integ and String loaded by
   485 default; theory Main includes everything;
   486 
   487 * automatic simplification of integer sums and comparisons, using cancellation;
   488 
   489 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   490 
   491 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   492 
   493 * many new identities for unions, intersections, set difference, etc.;
   494 
   495 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   496 called split_if, split_split, split_sum_case and split_nat_case (to go
   497 with add/delsplits);
   498 
   499 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   500 (?x::unit) = (); this is made part of the default simpset, which COULD
   501 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   502 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   503 unit_abs_eta_conv is added in order to counter the effect of
   504 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   505 %u.f();
   506 
   507 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   508 makes more sense);
   509 
   510 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   511   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   512   disjointness reasoning but breaking a few old proofs.
   513 
   514 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   515 to 'converse' from 'inverse' (for compatibility with ZF and some
   516 literature);
   517 
   518 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   519 the well-founded relation;
   520 
   521 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   522     Compl A.  The "Compl" syntax remains available as input syntax for this
   523     release ONLY.
   524 
   525 * HOL/Update: new theory of function updates:
   526     f(a:=b) == %x. if x=a then b else f x
   527 may also be iterated as in f(a:=b,c:=d,...);
   528 
   529 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   530 
   531 * HOL/List:
   532   - new function list_update written xs[i:=v] that updates the i-th
   533     list position. May also be iterated as in xs[i:=a,j:=b,...].
   534   - new function `upt' written [i..j(] which generates the list
   535     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   536     bound write [i..j], which is a shorthand for [i..j+1(].
   537   - new lexicographic orderings and corresponding wellfoundedness theorems.
   538 
   539 * HOL/Arith:
   540   - removed 'pred' (predecessor) function;
   541   - generalized some theorems about n-1;
   542   - many new laws about "div" and "mod";
   543   - new laws about greatest common divisors (see theory ex/Primes);
   544 
   545 * HOL/Relation: renamed the relational operator r^-1 "converse"
   546 instead of "inverse";
   547 
   548 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   549   of the multiset ordering;
   550 
   551 * directory HOL/Real: a construction of the reals using Dedekind cuts
   552   (not included by default);
   553 
   554 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   555 
   556 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   557   programs, i.e. different program variables may have different types.
   558 
   559 * calling (stac rew i) now fails if "rew" has no effect on the goal
   560   [previously, this check worked only if the rewrite rule was unconditional]
   561   Now rew can involve either definitions or equalities (either == or =).
   562 
   563 
   564 *** ZF ***
   565 
   566 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   567   only the theorems proved on ZF.ML;
   568 
   569 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   570   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   571   disjointness reasoning but breaking a few old proofs.
   572 
   573 * ZF/Update: new theory of function updates
   574     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   575   may also be iterated as in f(a:=b,c:=d,...);
   576 
   577 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   578 
   579 * calling (stac rew i) now fails if "rew" has no effect on the goal
   580   [previously, this check worked only if the rewrite rule was unconditional]
   581   Now rew can involve either definitions or equalities (either == or =).
   582 
   583 * case_tac provided for compatibility with HOL
   584     (like the old excluded_middle_tac, but with subgoals swapped)
   585 
   586 
   587 *** Internal programming interfaces ***
   588 
   589 * Pure: several new basic modules made available for general use, see
   590 also src/Pure/README;
   591 
   592 * improved the theory data mechanism to support encapsulation (data
   593 kind name replaced by private Object.kind, acting as authorization
   594 key); new type-safe user interface via functor TheoryDataFun; generic
   595 print_data function becomes basically useless;
   596 
   597 * removed global_names compatibility flag -- all theory declarations
   598 are qualified by default;
   599 
   600 * module Pure/Syntax now offers quote / antiquote translation
   601 functions (useful for Hoare logic etc. with implicit dependencies);
   602 see HOL/ex/Antiquote for an example use;
   603 
   604 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   605 cterm -> thm;
   606 
   607 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   608 subgoal;
   609 
   610 * Display.print_goals function moved to Locale.print_goals;
   611 
   612 * standard print function for goals supports current_goals_markers
   613 variable for marking begin of proof, end of proof, start of goal; the
   614 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   615 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   616 for example;
   617 
   618 
   619 
   620 New in Isabelle98 (January 1998)
   621 --------------------------------
   622 
   623 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   624 
   625 * changed lexical syntax of terms / types: dots made part of long
   626 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   627 
   628 * simpset (and claset) reference variable replaced by functions
   629 simpset / simpset_ref;
   630 
   631 * no longer supports theory aliases (via merge) and non-trivial
   632 implicit merge of thms' signatures;
   633 
   634 * most internal names of constants changed due to qualified names;
   635 
   636 * changed Pure/Sequence interface (see Pure/seq.ML);
   637 
   638 
   639 *** General Changes ***
   640 
   641 * hierachically structured name spaces (for consts, types, axms, thms
   642 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   643 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   644 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   645 long_names for fully qualified output names; NOTE: ML programs
   646 (special tactics, packages etc.) referring to internal names may have
   647 to be adapted to cope with fully qualified names; in case of severe
   648 backward campatibility problems try setting 'global_names' at compile
   649 time to have enrything declared within a flat name space; one may also
   650 fine tune name declarations in theories via the 'global' and 'local'
   651 section;
   652 
   653 * reimplemented the implicit simpset and claset using the new anytype
   654 data filed in signatures; references simpset:simpset ref etc. are
   655 replaced by functions simpset:unit->simpset and
   656 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   657 to patch your ML files accordingly;
   658 
   659 * HTML output now includes theory graph data for display with Java
   660 applet or isatool browser; data generated automatically via isatool
   661 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   662 
   663 * defs may now be conditional; improved rewrite_goals_tac to handle
   664 conditional equations;
   665 
   666 * defs now admits additional type arguments, using TYPE('a) syntax;
   667 
   668 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   669 creates a new theory node; implicit merge of thms' signatures is
   670 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   671 transfer:theory->thm->thm in (rare) cases;
   672 
   673 * improved handling of draft signatures / theories; draft thms (and
   674 ctyps, cterms) are automatically promoted to real ones;
   675 
   676 * slightly changed interfaces for oracles: admit many per theory, named
   677 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   678 
   679 * print_goals: optional output of const types (set show_consts and
   680 show_types);
   681 
   682 * improved output of warnings (###) and errors (***);
   683 
   684 * subgoal_tac displays a warning if the new subgoal has type variables;
   685 
   686 * removed old README and Makefiles;
   687 
   688 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   689 
   690 * removed obsolete init_pps and init_database;
   691 
   692 * deleted the obsolete tactical STATE, which was declared by
   693     fun STATE tacfun st = tacfun st st;
   694 
   695 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   696 (which abbreviates $HOME);
   697 
   698 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   699 use isatool fixseq to adapt your ML programs (this works for fully
   700 qualified references to the Sequence structure only!);
   701 
   702 * use_thy no longer requires writable current directory; it always
   703 reloads .ML *and* .thy file, if either one is out of date;
   704 
   705 
   706 *** Classical Reasoner ***
   707 
   708 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   709 tactics that use classical reasoning to simplify a subgoal without
   710 splitting it into several subgoals;
   711 
   712 * Safe_tac: like safe_tac but uses the default claset;
   713 
   714 
   715 *** Simplifier ***
   716 
   717 * added simplification meta rules:
   718     (asm_)(full_)simplify: simpset -> thm -> thm;
   719 
   720 * simplifier.ML no longer part of Pure -- has to be loaded by object
   721 logics (again);
   722 
   723 * added prems argument to simplification procedures;
   724 
   725 * HOL, FOL, ZF: added infix function `addsplits':
   726   instead of `<simpset> setloop (split_tac <thms>)'
   727   you can simply write `<simpset> addsplits <thms>'
   728 
   729 
   730 *** Syntax ***
   731 
   732 * TYPE('a) syntax for type reflection terms;
   733 
   734 * no longer handles consts with name "" -- declare as 'syntax' instead;
   735 
   736 * pretty printer: changed order of mixfix annotation preference (again!);
   737 
   738 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   739 
   740 
   741 *** HOL ***
   742 
   743 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   744   with `addloop' of the simplifier to faciliate case splitting in premises.
   745 
   746 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   747 
   748 * HOL/Auth: new protocol proofs including some for the Internet
   749   protocol TLS;
   750 
   751 * HOL/Map: new theory of `maps' a la VDM;
   752 
   753 * HOL/simplifier: simplification procedures nat_cancel_sums for
   754 cancelling out common nat summands from =, <, <= (in)equalities, or
   755 differences; simplification procedures nat_cancel_factor for
   756 cancelling common factor from =, <, <= (in)equalities over natural
   757 sums; nat_cancel contains both kinds of procedures, it is installed by
   758 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   759 
   760 * HOL/simplifier: terms of the form
   761   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   762   are rewritten to
   763   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   764   and those of the form
   765   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   766   are rewritten to
   767   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   768 
   769 * HOL/datatype
   770   Each datatype `t' now comes with a theorem `split_t_case' of the form
   771 
   772   P(t_case f1 ... fn x) =
   773      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   774         ...
   775        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   776      )
   777 
   778   and a theorem `split_t_case_asm' of the form
   779 
   780   P(t_case f1 ... fn x) =
   781     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   782         ...
   783        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   784      )
   785   which can be added to a simpset via `addsplits'. The existing theorems
   786   expand_list_case and expand_option_case have been renamed to
   787   split_list_case and split_option_case.
   788 
   789 * HOL/Arithmetic:
   790   - `pred n' is automatically converted to `n-1'.
   791     Users are strongly encouraged not to use `pred' any longer,
   792     because it will disappear altogether at some point.
   793   - Users are strongly encouraged to write "0 < n" rather than
   794     "n ~= 0". Theorems and proof tools have been modified towards this
   795     `standard'.
   796 
   797 * HOL/Lists:
   798   the function "set_of_list" has been renamed "set" (and its theorems too);
   799   the function "nth" now takes its arguments in the reverse order and
   800   has acquired the infix notation "!" as in "xs!n".
   801 
   802 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   803 
   804 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   805   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   806 
   807 * HOL/record: extensible records with schematic structural subtyping
   808 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   809 still lacks various theorems and concrete record syntax;
   810 
   811 
   812 *** HOLCF ***
   813 
   814 * removed "axioms" and "generated by" sections;
   815 
   816 * replaced "ops" section by extended "consts" section, which is capable of
   817   handling the continuous function space "->" directly;
   818 
   819 * domain package:
   820   . proves theorems immediately and stores them in the theory,
   821   . creates hierachical name space,
   822   . now uses normal mixfix annotations (instead of cinfix...),
   823   . minor changes to some names and values (for consistency),
   824   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   825   . separator between mutual domain defs: changed "," to "and",
   826   . improved handling of sort constraints;  now they have to
   827     appear on the left-hand side of the equations only;
   828 
   829 * fixed LAM <x,y,zs>.b syntax;
   830 
   831 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   832 adm (%x. P (t x)), where P is chainfinite and t continuous;
   833 
   834 
   835 *** FOL and ZF ***
   836 
   837 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   838   with `addloop' of the simplifier to faciliate case splitting in premises.
   839 
   840 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   841 in HOL, they strip ALL and --> from proved theorems;
   842 
   843 
   844 
   845 New in Isabelle94-8 (May 1997)
   846 ------------------------------
   847 
   848 *** General Changes ***
   849 
   850 * new utilities to build / run / maintain Isabelle etc. (in parts
   851 still somewhat experimental); old Makefiles etc. still functional;
   852 
   853 * new 'Isabelle System Manual';
   854 
   855 * INSTALL text, together with ./configure and ./build scripts;
   856 
   857 * reimplemented type inference for greater efficiency, better error
   858 messages and clean internal interface;
   859 
   860 * prlim command for dealing with lots of subgoals (an easier way of
   861 setting goals_limit);
   862 
   863 
   864 *** Syntax ***
   865 
   866 * supports alternative (named) syntax tables (parser and pretty
   867 printer); internal interface is provided by add_modesyntax(_i);
   868 
   869 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   870 be used in conjunction with the Isabelle symbol font; uses the
   871 "symbols" syntax table;
   872 
   873 * added token_translation interface (may translate name tokens in
   874 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   875 the current print_mode); IMPORTANT: user print translation functions
   876 are responsible for marking newly introduced bounds
   877 (Syntax.mark_boundT);
   878 
   879 * token translations for modes "xterm" and "xterm_color" that display
   880 names in bold, underline etc. or colors (which requires a color
   881 version of xterm);
   882 
   883 * infixes may now be declared with names independent of their syntax;
   884 
   885 * added typed_print_translation (like print_translation, but may
   886 access type of constant);
   887 
   888 
   889 *** Classical Reasoner ***
   890 
   891 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   892 some limitations.  Blast_tac...
   893   + ignores addss, addbefore, addafter; this restriction is intrinsic
   894   + ignores elimination rules that don't have the correct format
   895         (the conclusion MUST be a formula variable)
   896   + ignores types, which can make HOL proofs fail
   897   + rules must not require higher-order unification, e.g. apply_type in ZF
   898     [message "Function Var's argument not a bound variable" relates to this]
   899   + its proof strategy is more general but can actually be slower
   900 
   901 * substitution with equality assumptions no longer permutes other
   902 assumptions;
   903 
   904 * minor changes in semantics of addafter (now called addaltern); renamed
   905 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   906 (and access functions for it);
   907 
   908 * improved combination of classical reasoner and simplifier:
   909   + functions for handling clasimpsets
   910   + improvement of addss: now the simplifier is called _after_ the
   911     safe steps.
   912   + safe variant of addss called addSss: uses safe simplifications
   913     _during_ the safe steps. It is more complete as it allows multiple
   914     instantiations of unknowns (e.g. with slow_tac).
   915 
   916 *** Simplifier ***
   917 
   918 * added interface for simplification procedures (functions that
   919 produce *proven* rewrite rules on the fly, depending on current
   920 redex);
   921 
   922 * ordering on terms as parameter (used for ordered rewriting);
   923 
   924 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   925 
   926 * the solver is now split into a safe and an unsafe part.
   927 This should be invisible for the normal user, except that the
   928 functions setsolver and addsolver have been renamed to setSolver and
   929 addSolver; added safe_asm_full_simp_tac;
   930 
   931 
   932 *** HOL ***
   933 
   934 * a generic induction tactic `induct_tac' which works for all datatypes and
   935 also for type `nat';
   936 
   937 * a generic case distinction tactic `exhaust_tac' which works for all
   938 datatypes and also for type `nat';
   939 
   940 * each datatype comes with a function `size';
   941 
   942 * patterns in case expressions allow tuple patterns as arguments to
   943 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   944 
   945 * primrec now also works with type nat;
   946 
   947 * recdef: a new declaration form, allows general recursive functions to be
   948 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   949 
   950 * the constant for negation has been renamed from "not" to "Not" to
   951 harmonize with FOL, ZF, LK, etc.;
   952 
   953 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   954 infinite lists;
   955 
   956 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   957 
   958 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   959 problems in commutative rings, using axiomatic type classes for + and *;
   960 
   961 * more examples in HOL/MiniML and HOL/Auth;
   962 
   963 * more default rewrite rules for quantifiers, union/intersection;
   964 
   965 * a new constant `arbitrary == @x.False';
   966 
   967 * HOLCF/IOA replaces old HOL/IOA;
   968 
   969 * HOLCF changes: derived all rules and arities
   970   + axiomatic type classes instead of classes
   971   + typedef instead of faking type definitions
   972   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   973   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   974   + eliminated the types void, one, tr
   975   + use unit lift and bool lift (with translations) instead of one and tr
   976   + eliminated blift from Lift3.thy (use Def instead of blift)
   977   all eliminated rules are derived as theorems --> no visible changes ;
   978 
   979 
   980 *** ZF ***
   981 
   982 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
   983 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
   984 as ZF_cs addSIs [equalityI];
   985 
   986 
   987 
   988 New in Isabelle94-7 (November 96)
   989 ---------------------------------
   990 
   991 * allowing negative levels (as offsets) in prlev and choplev;
   992 
   993 * super-linear speedup for large simplifications;
   994 
   995 * FOL, ZF and HOL now use miniscoping: rewriting pushes
   996 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
   997 FAIL); can suppress it using the command Delsimps (ex_simps @
   998 all_simps); De Morgan laws are also now included, by default;
   999 
  1000 * improved printing of ==>  :  ~:
  1001 
  1002 * new object-logic "Sequents" adds linear logic, while replacing LK
  1003 and Modal (thanks to Sara Kalvala);
  1004 
  1005 * HOL/Auth: correctness proofs for authentication protocols;
  1006 
  1007 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1008 examples on HOL/Auth);
  1009 
  1010 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1011 the rewriter and classical reasoner simultaneously;
  1012 
  1013 * function uresult no longer returns theorems in "standard" format;
  1014 regain previous version by: val uresult = standard o uresult;
  1015 
  1016 
  1017 
  1018 New in Isabelle94-6
  1019 -------------------
  1020 
  1021 * oracles -- these establish an interface between Isabelle and trusted
  1022 external reasoners, which may deliver results as theorems;
  1023 
  1024 * proof objects (in particular record all uses of oracles);
  1025 
  1026 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1027 
  1028 * "constdefs" section in theory files;
  1029 
  1030 * "primrec" section (HOL) no longer requires names;
  1031 
  1032 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1033 
  1034 
  1035 
  1036 New in Isabelle94-5
  1037 -------------------
  1038 
  1039 * reduced space requirements;
  1040 
  1041 * automatic HTML generation from theories;
  1042 
  1043 * theory files no longer require "..." (quotes) around most types;
  1044 
  1045 * new examples, including two proofs of the Church-Rosser theorem;
  1046 
  1047 * non-curried (1994) version of HOL is no longer distributed;
  1048 
  1049 
  1050 
  1051 New in Isabelle94-4
  1052 -------------------
  1053 
  1054 * greatly reduced space requirements;
  1055 
  1056 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1057 
  1058 * searchable theorem database (see the section "Retrieving theorems" on
  1059 page 8 of the Reference Manual);
  1060 
  1061 * new examples, including Grabczewski's monumental case study of the
  1062 Axiom of Choice;
  1063 
  1064 * The previous version of HOL renamed to Old_HOL;
  1065 
  1066 * The new version of HOL (previously called CHOL) uses a curried syntax
  1067 for functions.  Application looks like f a b instead of f(a,b);
  1068 
  1069 * Mutually recursive inductive definitions finally work in HOL;
  1070 
  1071 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1072 translates to the operator "split";
  1073 
  1074 
  1075 
  1076 New in Isabelle94-3
  1077 -------------------
  1078 
  1079 * new infix operator, addss, allowing the classical reasoner to
  1080 perform simplification at each step of its search.  Example:
  1081         fast_tac (cs addss ss)
  1082 
  1083 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1084 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1085 look like (a,b) instead of <a,b>;
  1086 
  1087 * PLEASE NOTE: CHOL will eventually replace HOL!
  1088 
  1089 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1090 It translates to the operator "split".  A new theory of integers is available;
  1091 
  1092 * In ZF, integer numerals now denote two's-complement binary integers.
  1093 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1094 
  1095 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1096 of the Axiom of Choice;
  1097 
  1098 
  1099 
  1100 New in Isabelle94-2
  1101 -------------------
  1102 
  1103 * Significantly faster resolution;
  1104 
  1105 * the different sections in a .thy file can now be mixed and repeated
  1106 freely;
  1107 
  1108 * Database of theorems for FOL, HOL and ZF.  New
  1109 commands including qed, qed_goal and bind_thm store theorems in the database.
  1110 
  1111 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1112 a given theory (thms_of), or find out what theory a theorem was proved in
  1113 (theory_of_thm);
  1114 
  1115 * Bugs fixed in the inductive definition and datatype packages;
  1116 
  1117 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1118 and HOL_dup_cs obsolete;
  1119 
  1120 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1121 have been removed;
  1122 
  1123 * Simpler definition of function space in ZF;
  1124 
  1125 * new results about cardinal and ordinal arithmetic in ZF;
  1126 
  1127 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1128 types;
  1129 
  1130 
  1131 $Id$