NEWS
author paulson
Fri Sep 24 16:33:57 1999 +0200 (1999-09-24 ago)
changeset 7594 8a188ef6545e
parent 7593 6bc8fa8b4b24
child 7595 5f5d575ddac3
permissions -rw-r--r--
working version with co-guarantees-leadsto results
     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', `int', and `real' in HOL (see below); it can, should and
    39 will be 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 
    47 *** General ***
    48 
    49 * new Isabelle/Isar subsystem provides an alternative to traditional
    50 tactical theorem proving; together with the ProofGeneral/isar user
    51 interface it offers an interactive environment for developing human
    52 readable proof documents (Isar == Intelligible semi-automated
    53 reasoning); see isatool doc isar-ref and
    54 http://isabelle.in.tum.de/Isar/ for more information;
    55 
    56 * native support for Proof General, both for classic Isabelle and
    57 Isabelle/Isar (the latter is slightly better supported and more
    58 robust);
    59 
    60 * Isabelle manuals now also available as PDF;
    61 
    62 * improved browser info generation: better HTML markup (including
    63 colors), graph views in several sizes; isatool usedir now provides a
    64 proper interface for user theories (via -P option);
    65 
    66 * theory loader rewritten from scratch (may not be fully
    67 bug-compatible); old loadpath variable has been replaced by show_path,
    68 add_path, del_path, reset_path functions; new operations such as
    69 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
    70 isatool doc ref);
    71 
    72 * improved isatool install: option -k creates KDE application icon,
    73 option -p DIR installs standalone binaries;
    74 
    75 * added ML_PLATFORM setting (useful for cross-platform installations);
    76 more robust handling of platform specific ML images for SML/NJ;
    77 
    78 * path element specification '~~' refers to '$ISABELLE_HOME';
    79 
    80 * in locales, the "assumes" and "defines" parts may be omitted if
    81 empty;
    82 
    83 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
    84 long arrows);
    85 
    86 * new print_mode "HTML";
    87 
    88 * new flag show_tags controls display of tags of theorems (which are
    89 basically just comments that may be attached by some tools);
    90 
    91 * Isamode 2.6 requires patch to accomodate change of Isabelle font
    92 mode and goal output format:
    93 
    94 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
    95 244c244
    96 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
    97 ---
    98 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
    99 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   100 181c181
   101 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   102 ---
   103 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   104 
   105 * function bind_thms stores lists of theorems (cf. bind_thm);
   106 
   107 * new shorthand tactics ftac, eatac, datac, fatac;
   108 
   109 * qed (and friends) now accept "" as result name; in that case the
   110 result is not stored, but proper checks and presentation of the result
   111 still apply;
   112 
   113 
   114 *** HOL ***
   115 
   116 ** HOL arithmetic **
   117 
   118 * There are now decision procedures for linear arithmetic over nat and
   119 int:
   120 
   121 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   122 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   123 are treated as atomic; subformulae not involving type `nat' or `int'
   124 are ignored; quantified subformulae are ignored unless they are
   125 positive universal or negative existential. The tactic has to be
   126 invoked by hand and can be a little bit slow. In particular, the
   127 running time is exponential in the number of occurrences of `min' and
   128 `max', and `-' on `nat'.
   129 
   130 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   131 (negated) (in)equalities among the premises and the conclusion into
   132 account (i.e. no compound formulae) and does not know about `min' and
   133 `max', and `-' on `nat'. It is fast and is used automatically by the
   134 simplifier.
   135 
   136 NB: At the moment, these decision procedures do not cope with mixed
   137 nat/int formulae where the two parts interact, such as `m < n ==>
   138 int(m) < int(n)'.
   139 
   140 * HOL/Numeral provides a generic theory of numerals (encoded
   141 efficiently as bit strings); setup for types nat/int/real is in place;
   142 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   143 int, existing theories and proof scripts may require a few additional
   144 type constraints;
   145 
   146 * integer division and remainder can now be performed on constant
   147 arguments;
   148 
   149 * many properties of integer multiplication, division and remainder
   150 are now available;
   151 
   152 * An interface to the Stanford Validity Checker (SVC) is available through the
   153 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   154 are proved automatically.  SVC must be installed separately, and its results
   155 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   156 invocation of the underlying oracle).  For SVC see
   157   http://verify.stanford.edu/SVC
   158 
   159 * IsaMakefile: the HOL-Real target now builds an actual image;
   160 
   161 
   162 ** HOL misc **
   163 
   164 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   165 -- avoids syntactic ambiguities and treats state, transition, and
   166 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   167 changed syntax and (many) tactics;
   168 
   169 * HOL/datatype: Now also handles arbitrarily branching datatypes
   170   (using function types) such as
   171 
   172   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   173 
   174 * HOL/record: record_simproc (part of the default simpset) takes care
   175 of selectors applied to updated records; record_split_tac is no longer
   176 part of the default claset; update_defs may now be removed from the
   177 simpset in many cases; COMPATIBILITY: old behavior achieved by
   178 
   179   claset_ref () := claset() addSWrapper record_split_wrapper;
   180   Delsimprocs [record_simproc]
   181 
   182 * HOL/typedef: fixed type inference for representing set; type
   183 arguments now have to occur explicitly on the rhs as type constraints;
   184 
   185 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   186 names rather than an ML expression;
   187 
   188 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   189 supplied later.  Program schemes can be defined, such as
   190     "While B C s = (if B s then While B C (C s) else s)"
   191 where the well-founded relation can be chosen after B and C have been given.
   192 
   193 * HOL/List: the constructors of type list are now Nil and Cons;
   194 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   195 course, ML tools referring to List.list.op # etc. have to be adapted;
   196 
   197 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   198 disabled by default; run isabelle with option -m HOL to get back to
   199 the original Gordon/HOL-style output;
   200 
   201 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   202 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   203 
   204 * HOL basic syntax simplified (more orthogonal): all variants of
   205 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   206 Eps operator is provided as well: "SOME x. P[x]";
   207 
   208 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   209 
   210 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   211 thus available for user theories;
   212 
   213 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   214 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   215 time;
   216 
   217 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec several
   218   times and then mp
   219 
   220 
   221 *** LK ***
   222 
   223 * the notation <<...>> is now available as a notation for sequences of
   224 formulas;
   225 
   226 * the simplifier is now installed
   227 
   228 * the axiom system has been generalized (thanks to Soren Heilmann) 
   229 
   230 * the classical reasoner now has a default rule database
   231 
   232 
   233 *** ZF ***
   234 
   235 * new primrec section allows primitive recursive functions to be given
   236 directly (as in HOL) over datatypes and the natural numbers;
   237 
   238 * new tactics induct_tac and exhaust_tac for induction (or case
   239 analysis) over datatypes and the natural numbers;
   240 
   241 * the datatype declaration of type T now defines the recursor T_rec;
   242 
   243 * simplification automatically does freeness reasoning for datatype
   244 constructors;
   245 
   246 * automatic type-inference, with AddTCs command to insert new
   247 type-checking rules;
   248 
   249 * datatype introduction rules are now added as Safe Introduction rules
   250 to the claset;
   251 
   252 * the syntax "if P then x else y" is now available in addition to
   253 if(P,x,y);
   254 
   255 
   256 *** Internal programming interfaces ***
   257 
   258 * structures Vartab / Termtab (instances of TableFun) offer efficient
   259 tables indexed by indexname_ord / term_ord (compatible with aconv);
   260 
   261 * AxClass.axclass_tac lost the theory argument;
   262 
   263 * tuned current_goals_markers semantics: begin / end goal avoids
   264 printing empty lines;
   265 
   266 * removed prs and prs_fn hook, which was broken because it did not
   267 include \n in its semantics, forcing writeln to add one
   268 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   269 string -> unit if you really want to output text without newline;
   270 
   271 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   272 plain output, interface builders may have to enable 'isabelle_font'
   273 mode to get Isabelle font glyphs as before;
   274 
   275 * refined token_translation interface; INCOMPATIBILITY: output length
   276 now of type real instead of int;
   277 
   278 * theory loader actions may be traced via new ThyInfo.add_hook
   279 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   280 your own database of information attached to *whole* theories -- as
   281 opposed to intra-theory data slots offered via TheoryDataFun;
   282 
   283 
   284 
   285 New in Isabelle98-1 (October 1998)
   286 ----------------------------------
   287 
   288 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   289 
   290 * several changes of automated proof tools;
   291 
   292 * HOL: major changes to the inductive and datatype packages, including
   293 some minor incompatibilities of theory syntax;
   294 
   295 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   296 called `inj_on';
   297 
   298 * HOL: removed duplicate thms in Arith:
   299   less_imp_add_less  should be replaced by  trans_less_add1
   300   le_imp_add_le      should be replaced by  trans_le_add1
   301 
   302 * HOL: unary minus is now overloaded (new type constraints may be
   303 required);
   304 
   305 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   306 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   307 now taken as an integer constant.
   308 
   309 * Pure: ML function 'theory_of' renamed to 'theory';
   310 
   311 
   312 *** Proof tools ***
   313 
   314 * Simplifier:
   315   1. Asm_full_simp_tac is now more aggressive.
   316      1. It will sometimes reorient premises if that increases their power to
   317         simplify.
   318      2. It does no longer proceed strictly from left to right but may also
   319         rotate premises to achieve further simplification.
   320      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   321      old Asm_full_simp_tac in that it does not rotate premises.
   322   2. The simplifier now knows a little bit about nat-arithmetic.
   323 
   324 * Classical reasoner: wrapper mechanism for the classical reasoner now
   325 allows for selected deletion of wrappers, by introduction of names for
   326 wrapper functionals.  This implies that addbefore, addSbefore,
   327 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   328 and that adding two tactics with the same name overwrites the first
   329 one (emitting a warning).
   330   type wrapper = (int -> tactic) -> (int -> tactic)
   331   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   332   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   333   delWrapper, delSWrapper: claset *  string            -> claset
   334   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   335 
   336 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   337 semantics; addbefore now affects only the unsafe part of step_tac
   338 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   339 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   340 by Force_tac;
   341 
   342 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   343 compWrapper; added safe wrapper (and access functions for it);
   344 
   345 * HOL/split_all_tac is now much faster and fails if there is nothing
   346 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   347 and the names of the automatically generated variables have changed.
   348 split_all_tac has moved within claset() from unsafe wrappers to safe
   349 wrappers, which means that !!-bound variables are split much more
   350 aggressively, and safe_tac and clarify_tac now split such variables.
   351 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   352 Note: the same holds for record_split_tac, which does the job of
   353 split_all_tac for record fields.
   354 
   355 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   356 permanently to the default simpset using Addsplits just like
   357 Addsimps. They can be removed via Delsplits just like
   358 Delsimps. Lower-case versions are also available.
   359 
   360 * HOL/Simplifier: The rule split_if is now part of the default
   361 simpset. This means that the simplifier will eliminate all occurrences
   362 of if-then-else in the conclusion of a goal. To prevent this, you can
   363 either remove split_if completely from the default simpset by
   364 `Delsplits [split_if]' or remove it in a specific call of the
   365 simplifier using `... delsplits [split_if]'.  You can also add/delete
   366 other case splitting rules to/from the default simpset: every datatype
   367 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   368 t is the name of the datatype).
   369 
   370 * Classical reasoner / Simplifier combination: new force_tac (and
   371 derivatives Force_tac, force) combines rewriting and classical
   372 reasoning (and whatever other tools) similarly to auto_tac, but is
   373 aimed to solve the given subgoal completely.
   374 
   375 
   376 *** General ***
   377 
   378 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   379 and `goalw': the theory is no longer needed as an explicit argument -
   380 the current theory context is used; assumptions are no longer returned
   381 at the ML-level unless one of them starts with ==> or !!; it is
   382 recommended to convert to these new commands using isatool fixgoal
   383 (backup your sources first!);
   384 
   385 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   386 the current theory context, and 'theory' to lookup stored theories;
   387 
   388 * new theory section 'locale' for declaring constants, assumptions and
   389 definitions that have local scope;
   390 
   391 * new theory section 'nonterminals' for purely syntactic types;
   392 
   393 * new theory section 'setup' for generic ML setup functions
   394 (e.g. package initialization);
   395 
   396 * the distribution now includes Isabelle icons: see
   397 lib/logo/isabelle-{small,tiny}.xpm;
   398 
   399 * isatool install - install binaries with absolute references to
   400 ISABELLE_HOME/bin;
   401 
   402 * isatool logo -- create instances of the Isabelle logo (as EPS);
   403 
   404 * print mode 'emacs' reserved for Isamode;
   405 
   406 * support multiple print (ast) translations per constant name;
   407 
   408 * theorems involving oracles are now printed with a suffixed [!];
   409 
   410 
   411 *** HOL ***
   412 
   413 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   414 
   415 * HOL/inductive package reorganized and improved: now supports mutual
   416 definitions such as
   417 
   418   inductive EVEN ODD
   419     intrs
   420       null "0 : EVEN"
   421       oddI "n : EVEN ==> Suc n : ODD"
   422       evenI "n : ODD ==> Suc n : EVEN"
   423 
   424 new theorem list "elims" contains an elimination rule for each of the
   425 recursive sets; inductive definitions now handle disjunctive premises
   426 correctly (also ZF);
   427 
   428 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   429 "mutual_induct" no longer exists - the induction rule is always
   430 contained in "induct";
   431 
   432 
   433 * HOL/datatype package re-implemented and greatly improved: now
   434 supports mutually recursive datatypes such as
   435 
   436   datatype
   437     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   438             | SUM ('a aexp) ('a aexp)
   439             | DIFF ('a aexp) ('a aexp)
   440             | NUM 'a
   441   and
   442     'a bexp = LESS ('a aexp) ('a aexp)
   443             | AND ('a bexp) ('a bexp)
   444             | OR ('a bexp) ('a bexp)
   445 
   446 as well as indirectly recursive datatypes such as
   447 
   448   datatype
   449     ('a, 'b) term = Var 'a
   450                   | App 'b ((('a, 'b) term) list)
   451 
   452 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   453 induction on mutually / indirectly recursive datatypes.
   454 
   455 Primrec equations are now stored in theory and can be accessed via
   456 <function_name>.simps.
   457 
   458 INCOMPATIBILITIES:
   459 
   460   - Theories using datatypes must now have theory Datatype as an
   461     ancestor.
   462   - The specific <typename>.induct_tac no longer exists - use the
   463     generic induct_tac instead.
   464   - natE has been renamed to nat.exhaust - use exhaust_tac
   465     instead of res_inst_tac ... natE. Note that the variable
   466     names in nat.exhaust differ from the names in natE, this
   467     may cause some "fragile" proofs to fail.
   468   - The theorems split_<typename>_case and split_<typename>_case_asm
   469     have been renamed to <typename>.split and <typename>.split_asm.
   470   - Since default sorts of type variables are now handled correctly,
   471     some datatype definitions may have to be annotated with explicit
   472     sort constraints.
   473   - Primrec definitions no longer require function name and type
   474     of recursive argument.
   475 
   476 Consider using isatool fixdatatype to adapt your theories and proof
   477 scripts to the new package (backup your sources first!).
   478 
   479 
   480 * HOL/record package: considerably improved implementation; now
   481 includes concrete syntax for record types, terms, updates; theorems
   482 for surjective pairing and splitting !!-bound record variables; proof
   483 support is as follows:
   484 
   485   1) standard conversions (selectors or updates applied to record
   486 constructor terms) are part of the standard simpset;
   487 
   488   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   489 made part of standard simpset and claset via addIffs;
   490 
   491   3) a tactic for record field splitting (record_split_tac) is part of
   492 the standard claset (addSWrapper);
   493 
   494 To get a better idea about these rules you may retrieve them via
   495 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   496 the name of your record type.
   497 
   498 The split tactic 3) conceptually simplifies by the following rule:
   499 
   500   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   501 
   502 Thus any record variable that is bound by meta-all will automatically
   503 blow up into some record constructor term, consequently the
   504 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   505 solve record problems automatically.
   506 
   507 
   508 * reorganized the main HOL image: HOL/Integ and String loaded by
   509 default; theory Main includes everything;
   510 
   511 * automatic simplification of integer sums and comparisons, using cancellation;
   512 
   513 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   514 
   515 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   516 
   517 * many new identities for unions, intersections, set difference, etc.;
   518 
   519 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   520 called split_if, split_split, split_sum_case and split_nat_case (to go
   521 with add/delsplits);
   522 
   523 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   524 (?x::unit) = (); this is made part of the default simpset, which COULD
   525 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   526 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   527 unit_abs_eta_conv is added in order to counter the effect of
   528 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   529 %u.f();
   530 
   531 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   532 makes more sense);
   533 
   534 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   535   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   536   disjointness reasoning but breaking a few old proofs.
   537 
   538 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   539 to 'converse' from 'inverse' (for compatibility with ZF and some
   540 literature);
   541 
   542 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   543 the well-founded relation;
   544 
   545 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   546     Compl A.  The "Compl" syntax remains available as input syntax for this
   547     release ONLY.
   548 
   549 * HOL/Update: new theory of function updates:
   550     f(a:=b) == %x. if x=a then b else f x
   551 may also be iterated as in f(a:=b,c:=d,...);
   552 
   553 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   554 
   555 * HOL/List:
   556   - new function list_update written xs[i:=v] that updates the i-th
   557     list position. May also be iterated as in xs[i:=a,j:=b,...].
   558   - new function `upt' written [i..j(] which generates the list
   559     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   560     bound write [i..j], which is a shorthand for [i..j+1(].
   561   - new lexicographic orderings and corresponding wellfoundedness theorems.
   562 
   563 * HOL/Arith:
   564   - removed 'pred' (predecessor) function;
   565   - generalized some theorems about n-1;
   566   - many new laws about "div" and "mod";
   567   - new laws about greatest common divisors (see theory ex/Primes);
   568 
   569 * HOL/Relation: renamed the relational operator r^-1 "converse"
   570 instead of "inverse";
   571 
   572 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   573   of the multiset ordering;
   574 
   575 * directory HOL/Real: a construction of the reals using Dedekind cuts
   576   (not included by default);
   577 
   578 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   579 
   580 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   581   programs, i.e. different program variables may have different types.
   582 
   583 * calling (stac rew i) now fails if "rew" has no effect on the goal
   584   [previously, this check worked only if the rewrite rule was unconditional]
   585   Now rew can involve either definitions or equalities (either == or =).
   586 
   587 
   588 *** ZF ***
   589 
   590 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   591   only the theorems proved on ZF.ML;
   592 
   593 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   594   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   595   disjointness reasoning but breaking a few old proofs.
   596 
   597 * ZF/Update: new theory of function updates
   598     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   599   may also be iterated as in f(a:=b,c:=d,...);
   600 
   601 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   602 
   603 * calling (stac rew i) now fails if "rew" has no effect on the goal
   604   [previously, this check worked only if the rewrite rule was unconditional]
   605   Now rew can involve either definitions or equalities (either == or =).
   606 
   607 * case_tac provided for compatibility with HOL
   608     (like the old excluded_middle_tac, but with subgoals swapped)
   609 
   610 
   611 *** Internal programming interfaces ***
   612 
   613 * Pure: several new basic modules made available for general use, see
   614 also src/Pure/README;
   615 
   616 * improved the theory data mechanism to support encapsulation (data
   617 kind name replaced by private Object.kind, acting as authorization
   618 key); new type-safe user interface via functor TheoryDataFun; generic
   619 print_data function becomes basically useless;
   620 
   621 * removed global_names compatibility flag -- all theory declarations
   622 are qualified by default;
   623 
   624 * module Pure/Syntax now offers quote / antiquote translation
   625 functions (useful for Hoare logic etc. with implicit dependencies);
   626 see HOL/ex/Antiquote for an example use;
   627 
   628 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   629 cterm -> thm;
   630 
   631 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   632 subgoal;
   633 
   634 * Display.print_goals function moved to Locale.print_goals;
   635 
   636 * standard print function for goals supports current_goals_markers
   637 variable for marking begin of proof, end of proof, start of goal; the
   638 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   639 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   640 for example;
   641 
   642 
   643 
   644 New in Isabelle98 (January 1998)
   645 --------------------------------
   646 
   647 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   648 
   649 * changed lexical syntax of terms / types: dots made part of long
   650 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   651 
   652 * simpset (and claset) reference variable replaced by functions
   653 simpset / simpset_ref;
   654 
   655 * no longer supports theory aliases (via merge) and non-trivial
   656 implicit merge of thms' signatures;
   657 
   658 * most internal names of constants changed due to qualified names;
   659 
   660 * changed Pure/Sequence interface (see Pure/seq.ML);
   661 
   662 
   663 *** General Changes ***
   664 
   665 * hierachically structured name spaces (for consts, types, axms, thms
   666 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   667 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   668 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   669 long_names for fully qualified output names; NOTE: ML programs
   670 (special tactics, packages etc.) referring to internal names may have
   671 to be adapted to cope with fully qualified names; in case of severe
   672 backward campatibility problems try setting 'global_names' at compile
   673 time to have enrything declared within a flat name space; one may also
   674 fine tune name declarations in theories via the 'global' and 'local'
   675 section;
   676 
   677 * reimplemented the implicit simpset and claset using the new anytype
   678 data filed in signatures; references simpset:simpset ref etc. are
   679 replaced by functions simpset:unit->simpset and
   680 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   681 to patch your ML files accordingly;
   682 
   683 * HTML output now includes theory graph data for display with Java
   684 applet or isatool browser; data generated automatically via isatool
   685 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   686 
   687 * defs may now be conditional; improved rewrite_goals_tac to handle
   688 conditional equations;
   689 
   690 * defs now admits additional type arguments, using TYPE('a) syntax;
   691 
   692 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   693 creates a new theory node; implicit merge of thms' signatures is
   694 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   695 transfer:theory->thm->thm in (rare) cases;
   696 
   697 * improved handling of draft signatures / theories; draft thms (and
   698 ctyps, cterms) are automatically promoted to real ones;
   699 
   700 * slightly changed interfaces for oracles: admit many per theory, named
   701 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   702 
   703 * print_goals: optional output of const types (set show_consts and
   704 show_types);
   705 
   706 * improved output of warnings (###) and errors (***);
   707 
   708 * subgoal_tac displays a warning if the new subgoal has type variables;
   709 
   710 * removed old README and Makefiles;
   711 
   712 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   713 
   714 * removed obsolete init_pps and init_database;
   715 
   716 * deleted the obsolete tactical STATE, which was declared by
   717     fun STATE tacfun st = tacfun st st;
   718 
   719 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   720 (which abbreviates $HOME);
   721 
   722 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   723 use isatool fixseq to adapt your ML programs (this works for fully
   724 qualified references to the Sequence structure only!);
   725 
   726 * use_thy no longer requires writable current directory; it always
   727 reloads .ML *and* .thy file, if either one is out of date;
   728 
   729 
   730 *** Classical Reasoner ***
   731 
   732 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   733 tactics that use classical reasoning to simplify a subgoal without
   734 splitting it into several subgoals;
   735 
   736 * Safe_tac: like safe_tac but uses the default claset;
   737 
   738 
   739 *** Simplifier ***
   740 
   741 * added simplification meta rules:
   742     (asm_)(full_)simplify: simpset -> thm -> thm;
   743 
   744 * simplifier.ML no longer part of Pure -- has to be loaded by object
   745 logics (again);
   746 
   747 * added prems argument to simplification procedures;
   748 
   749 * HOL, FOL, ZF: added infix function `addsplits':
   750   instead of `<simpset> setloop (split_tac <thms>)'
   751   you can simply write `<simpset> addsplits <thms>'
   752 
   753 
   754 *** Syntax ***
   755 
   756 * TYPE('a) syntax for type reflection terms;
   757 
   758 * no longer handles consts with name "" -- declare as 'syntax' instead;
   759 
   760 * pretty printer: changed order of mixfix annotation preference (again!);
   761 
   762 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   763 
   764 
   765 *** HOL ***
   766 
   767 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   768   with `addloop' of the simplifier to faciliate case splitting in premises.
   769 
   770 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   771 
   772 * HOL/Auth: new protocol proofs including some for the Internet
   773   protocol TLS;
   774 
   775 * HOL/Map: new theory of `maps' a la VDM;
   776 
   777 * HOL/simplifier: simplification procedures nat_cancel_sums for
   778 cancelling out common nat summands from =, <, <= (in)equalities, or
   779 differences; simplification procedures nat_cancel_factor for
   780 cancelling common factor from =, <, <= (in)equalities over natural
   781 sums; nat_cancel contains both kinds of procedures, it is installed by
   782 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   783 
   784 * HOL/simplifier: terms of the form
   785   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   786   are rewritten to
   787   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   788   and those of the form
   789   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   790   are rewritten to
   791   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   792 
   793 * HOL/datatype
   794   Each datatype `t' now comes with a theorem `split_t_case' of the form
   795 
   796   P(t_case f1 ... fn x) =
   797      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   798         ...
   799        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   800      )
   801 
   802   and a theorem `split_t_case_asm' of the form
   803 
   804   P(t_case f1 ... fn x) =
   805     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   806         ...
   807        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   808      )
   809   which can be added to a simpset via `addsplits'. The existing theorems
   810   expand_list_case and expand_option_case have been renamed to
   811   split_list_case and split_option_case.
   812 
   813 * HOL/Arithmetic:
   814   - `pred n' is automatically converted to `n-1'.
   815     Users are strongly encouraged not to use `pred' any longer,
   816     because it will disappear altogether at some point.
   817   - Users are strongly encouraged to write "0 < n" rather than
   818     "n ~= 0". Theorems and proof tools have been modified towards this
   819     `standard'.
   820 
   821 * HOL/Lists:
   822   the function "set_of_list" has been renamed "set" (and its theorems too);
   823   the function "nth" now takes its arguments in the reverse order and
   824   has acquired the infix notation "!" as in "xs!n".
   825 
   826 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   827 
   828 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   829   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   830 
   831 * HOL/record: extensible records with schematic structural subtyping
   832 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   833 still lacks various theorems and concrete record syntax;
   834 
   835 
   836 *** HOLCF ***
   837 
   838 * removed "axioms" and "generated by" sections;
   839 
   840 * replaced "ops" section by extended "consts" section, which is capable of
   841   handling the continuous function space "->" directly;
   842 
   843 * domain package:
   844   . proves theorems immediately and stores them in the theory,
   845   . creates hierachical name space,
   846   . now uses normal mixfix annotations (instead of cinfix...),
   847   . minor changes to some names and values (for consistency),
   848   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   849   . separator between mutual domain defs: changed "," to "and",
   850   . improved handling of sort constraints;  now they have to
   851     appear on the left-hand side of the equations only;
   852 
   853 * fixed LAM <x,y,zs>.b syntax;
   854 
   855 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   856 adm (%x. P (t x)), where P is chainfinite and t continuous;
   857 
   858 
   859 *** FOL and ZF ***
   860 
   861 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   862   with `addloop' of the simplifier to faciliate case splitting in premises.
   863 
   864 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   865 in HOL, they strip ALL and --> from proved theorems;
   866 
   867 
   868 
   869 New in Isabelle94-8 (May 1997)
   870 ------------------------------
   871 
   872 *** General Changes ***
   873 
   874 * new utilities to build / run / maintain Isabelle etc. (in parts
   875 still somewhat experimental); old Makefiles etc. still functional;
   876 
   877 * new 'Isabelle System Manual';
   878 
   879 * INSTALL text, together with ./configure and ./build scripts;
   880 
   881 * reimplemented type inference for greater efficiency, better error
   882 messages and clean internal interface;
   883 
   884 * prlim command for dealing with lots of subgoals (an easier way of
   885 setting goals_limit);
   886 
   887 
   888 *** Syntax ***
   889 
   890 * supports alternative (named) syntax tables (parser and pretty
   891 printer); internal interface is provided by add_modesyntax(_i);
   892 
   893 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   894 be used in conjunction with the Isabelle symbol font; uses the
   895 "symbols" syntax table;
   896 
   897 * added token_translation interface (may translate name tokens in
   898 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   899 the current print_mode); IMPORTANT: user print translation functions
   900 are responsible for marking newly introduced bounds
   901 (Syntax.mark_boundT);
   902 
   903 * token translations for modes "xterm" and "xterm_color" that display
   904 names in bold, underline etc. or colors (which requires a color
   905 version of xterm);
   906 
   907 * infixes may now be declared with names independent of their syntax;
   908 
   909 * added typed_print_translation (like print_translation, but may
   910 access type of constant);
   911 
   912 
   913 *** Classical Reasoner ***
   914 
   915 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   916 some limitations.  Blast_tac...
   917   + ignores addss, addbefore, addafter; this restriction is intrinsic
   918   + ignores elimination rules that don't have the correct format
   919         (the conclusion MUST be a formula variable)
   920   + ignores types, which can make HOL proofs fail
   921   + rules must not require higher-order unification, e.g. apply_type in ZF
   922     [message "Function Var's argument not a bound variable" relates to this]
   923   + its proof strategy is more general but can actually be slower
   924 
   925 * substitution with equality assumptions no longer permutes other
   926 assumptions;
   927 
   928 * minor changes in semantics of addafter (now called addaltern); renamed
   929 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   930 (and access functions for it);
   931 
   932 * improved combination of classical reasoner and simplifier:
   933   + functions for handling clasimpsets
   934   + improvement of addss: now the simplifier is called _after_ the
   935     safe steps.
   936   + safe variant of addss called addSss: uses safe simplifications
   937     _during_ the safe steps. It is more complete as it allows multiple
   938     instantiations of unknowns (e.g. with slow_tac).
   939 
   940 *** Simplifier ***
   941 
   942 * added interface for simplification procedures (functions that
   943 produce *proven* rewrite rules on the fly, depending on current
   944 redex);
   945 
   946 * ordering on terms as parameter (used for ordered rewriting);
   947 
   948 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   949 
   950 * the solver is now split into a safe and an unsafe part.
   951 This should be invisible for the normal user, except that the
   952 functions setsolver and addsolver have been renamed to setSolver and
   953 addSolver; added safe_asm_full_simp_tac;
   954 
   955 
   956 *** HOL ***
   957 
   958 * a generic induction tactic `induct_tac' which works for all datatypes and
   959 also for type `nat';
   960 
   961 * a generic case distinction tactic `exhaust_tac' which works for all
   962 datatypes and also for type `nat';
   963 
   964 * each datatype comes with a function `size';
   965 
   966 * patterns in case expressions allow tuple patterns as arguments to
   967 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
   968 
   969 * primrec now also works with type nat;
   970 
   971 * recdef: a new declaration form, allows general recursive functions to be
   972 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
   973 
   974 * the constant for negation has been renamed from "not" to "Not" to
   975 harmonize with FOL, ZF, LK, etc.;
   976 
   977 * HOL/ex/LFilter theory of a corecursive "filter" functional for
   978 infinite lists;
   979 
   980 * HOL/Modelcheck demonstrates invocation of model checker oracle;
   981 
   982 * HOL/ex/Ring.thy declares cring_simp, which solves equational
   983 problems in commutative rings, using axiomatic type classes for + and *;
   984 
   985 * more examples in HOL/MiniML and HOL/Auth;
   986 
   987 * more default rewrite rules for quantifiers, union/intersection;
   988 
   989 * a new constant `arbitrary == @x.False';
   990 
   991 * HOLCF/IOA replaces old HOL/IOA;
   992 
   993 * HOLCF changes: derived all rules and arities
   994   + axiomatic type classes instead of classes
   995   + typedef instead of faking type definitions
   996   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
   997   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
   998   + eliminated the types void, one, tr
   999   + use unit lift and bool lift (with translations) instead of one and tr
  1000   + eliminated blift from Lift3.thy (use Def instead of blift)
  1001   all eliminated rules are derived as theorems --> no visible changes ;
  1002 
  1003 
  1004 *** ZF ***
  1005 
  1006 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1007 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1008 as ZF_cs addSIs [equalityI];
  1009 
  1010 
  1011 
  1012 New in Isabelle94-7 (November 96)
  1013 ---------------------------------
  1014 
  1015 * allowing negative levels (as offsets) in prlev and choplev;
  1016 
  1017 * super-linear speedup for large simplifications;
  1018 
  1019 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1020 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1021 FAIL); can suppress it using the command Delsimps (ex_simps @
  1022 all_simps); De Morgan laws are also now included, by default;
  1023 
  1024 * improved printing of ==>  :  ~:
  1025 
  1026 * new object-logic "Sequents" adds linear logic, while replacing LK
  1027 and Modal (thanks to Sara Kalvala);
  1028 
  1029 * HOL/Auth: correctness proofs for authentication protocols;
  1030 
  1031 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1032 examples on HOL/Auth);
  1033 
  1034 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1035 the rewriter and classical reasoner simultaneously;
  1036 
  1037 * function uresult no longer returns theorems in "standard" format;
  1038 regain previous version by: val uresult = standard o uresult;
  1039 
  1040 
  1041 
  1042 New in Isabelle94-6
  1043 -------------------
  1044 
  1045 * oracles -- these establish an interface between Isabelle and trusted
  1046 external reasoners, which may deliver results as theorems;
  1047 
  1048 * proof objects (in particular record all uses of oracles);
  1049 
  1050 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1051 
  1052 * "constdefs" section in theory files;
  1053 
  1054 * "primrec" section (HOL) no longer requires names;
  1055 
  1056 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1057 
  1058 
  1059 
  1060 New in Isabelle94-5
  1061 -------------------
  1062 
  1063 * reduced space requirements;
  1064 
  1065 * automatic HTML generation from theories;
  1066 
  1067 * theory files no longer require "..." (quotes) around most types;
  1068 
  1069 * new examples, including two proofs of the Church-Rosser theorem;
  1070 
  1071 * non-curried (1994) version of HOL is no longer distributed;
  1072 
  1073 
  1074 
  1075 New in Isabelle94-4
  1076 -------------------
  1077 
  1078 * greatly reduced space requirements;
  1079 
  1080 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1081 
  1082 * searchable theorem database (see the section "Retrieving theorems" on
  1083 page 8 of the Reference Manual);
  1084 
  1085 * new examples, including Grabczewski's monumental case study of the
  1086 Axiom of Choice;
  1087 
  1088 * The previous version of HOL renamed to Old_HOL;
  1089 
  1090 * The new version of HOL (previously called CHOL) uses a curried syntax
  1091 for functions.  Application looks like f a b instead of f(a,b);
  1092 
  1093 * Mutually recursive inductive definitions finally work in HOL;
  1094 
  1095 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1096 translates to the operator "split";
  1097 
  1098 
  1099 
  1100 New in Isabelle94-3
  1101 -------------------
  1102 
  1103 * new infix operator, addss, allowing the classical reasoner to
  1104 perform simplification at each step of its search.  Example:
  1105         fast_tac (cs addss ss)
  1106 
  1107 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1108 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1109 look like (a,b) instead of <a,b>;
  1110 
  1111 * PLEASE NOTE: CHOL will eventually replace HOL!
  1112 
  1113 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1114 It translates to the operator "split".  A new theory of integers is available;
  1115 
  1116 * In ZF, integer numerals now denote two's-complement binary integers.
  1117 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1118 
  1119 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1120 of the Axiom of Choice;
  1121 
  1122 
  1123 
  1124 New in Isabelle94-2
  1125 -------------------
  1126 
  1127 * Significantly faster resolution;
  1128 
  1129 * the different sections in a .thy file can now be mixed and repeated
  1130 freely;
  1131 
  1132 * Database of theorems for FOL, HOL and ZF.  New
  1133 commands including qed, qed_goal and bind_thm store theorems in the database.
  1134 
  1135 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1136 a given theory (thms_of), or find out what theory a theorem was proved in
  1137 (theory_of_thm);
  1138 
  1139 * Bugs fixed in the inductive definition and datatype packages;
  1140 
  1141 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1142 and HOL_dup_cs obsolete;
  1143 
  1144 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1145 have been removed;
  1146 
  1147 * Simpler definition of function space in ZF;
  1148 
  1149 * new results about cardinal and ordinal arithmetic in ZF;
  1150 
  1151 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1152 types;
  1153 
  1154 
  1155 $Id$