NEWS
author berghofe
Wed Oct 13 15:18:15 1999 +0200 (1999-10-13)
changeset 7847 5a3fa0c4b215
parent 7805 0ae9ddc36fe0
child 7863 8b0aca9bdc26
permissions -rw-r--r--
Eliminated mutual_induct_tac.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle version
     5 ----------------------------
     6 
     7 *** Overview of INCOMPATIBILITIES (see below for more details) ***
     8 
     9 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
    10 are no longer simplified.  (This allows the simplifier to unfold recursive
    11 functional programs.)  To restore the old behaviour, declare
    12 
    13     Delcongs [if_weak_cong];
    14 
    15 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    16 complement;
    17 
    18 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    19 
    20 * HOL/datatype: mutual_induct_tac no longer exists --
    21   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
    22 
    23 * HOL/typedef: fixed type inference for representing set; type
    24 arguments now have to occur explicitly on the rhs as type constraints;
    25 
    26 * ZF: The con_defs part of an inductive definition may no longer refer
    27 to constants declared in the same theory;
    28 
    29 * HOL, ZF: the function mk_cases, generated by the inductive
    30 definition package, has lost an argument.  To simplify its result, it
    31 uses the default simpset instead of a supplied list of theorems.
    32 
    33 * HOL/List: the constructors of type list are now Nil and Cons;
    34 
    35 * Simplifier: the type of the infix ML functions
    36 	setSSolver addSSolver setSolver addSolver
    37 is now  simpset * solver -> simpset  where `solver' is a new abstract type
    38 for packaging solvers. A solver is created via
    39 	mk_solver: string -> (thm list -> int -> tactic) -> solver
    40 where the string argument is only a comment.
    41 
    42 
    43 *** Proof tools ***
    44 
    45 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
    46 decision procedure for linear arithmetic. Currently it is used for
    47 types `nat', `int', and `real' in HOL (see below); it can, should and
    48 will be instantiated for other types and logics as well.
    49 
    50 * The simplifier now accepts rewrite rules with flexible heads, eg
    51      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
    52   They are applied like any rule with a non-pattern lhs, i.e. by first-order
    53   matching.
    54 
    55 
    56 *** General ***
    57 
    58 * new Isabelle/Isar subsystem provides an alternative to traditional
    59 tactical theorem proving; together with the ProofGeneral/isar user
    60 interface it offers an interactive environment for developing human
    61 readable proof documents (Isar == Intelligible semi-automated
    62 reasoning); see isatool doc isar-ref and
    63 http://isabelle.in.tum.de/Isar/ for more information;
    64 
    65 * native support for Proof General, both for classic Isabelle and
    66 Isabelle/Isar (the latter is slightly better supported and more
    67 robust);
    68 
    69 * ML function thm_deps visualizes dependencies of theorems and lemmas,
    70 using the graph browser tool;
    71 
    72 * Isabelle manuals now also available as PDF;
    73 
    74 * improved browser info generation: better HTML markup (including
    75 colors), graph views in several sizes; isatool usedir now provides a
    76 proper interface for user theories (via -P option);
    77 
    78 * theory loader rewritten from scratch (may not be fully
    79 bug-compatible); old loadpath variable has been replaced by show_path,
    80 add_path, del_path, reset_path functions; new operations such as
    81 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
    82 isatool doc ref);
    83 
    84 * improved isatool install: option -k creates KDE application icon,
    85 option -p DIR installs standalone binaries;
    86 
    87 * added ML_PLATFORM setting (useful for cross-platform installations);
    88 more robust handling of platform specific ML images for SML/NJ;
    89 
    90 * path element specification '~~' refers to '$ISABELLE_HOME';
    91 
    92 * in locales, the "assumes" and "defines" parts may be omitted if
    93 empty;
    94 
    95 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
    96 long arrows);
    97 
    98 * new print_mode "HTML";
    99 
   100 * new flag show_tags controls display of tags of theorems (which are
   101 basically just comments that may be attached by some tools);
   102 
   103 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   104 mode and goal output format:
   105 
   106 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   107 244c244
   108 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   109 ---
   110 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   111 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   112 181c181
   113 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   114 ---
   115 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   116 
   117 * function bind_thms stores lists of theorems (cf. bind_thm);
   118 
   119 * new shorthand tactics ftac, eatac, datac, fatac;
   120 
   121 * qed (and friends) now accept "" as result name; in that case the
   122 result is not stored, but proper checks and presentation of the result
   123 still apply;
   124 
   125 * theorem database now also indexes constants "Trueprop", "all",
   126 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   127 
   128 
   129 *** HOL ***
   130 
   131 ** HOL arithmetic **
   132 
   133 * There are now decision procedures for linear arithmetic over nat and
   134 int:
   135 
   136 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   137 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   138 are treated as atomic; subformulae not involving type `nat' or `int'
   139 are ignored; quantified subformulae are ignored unless they are
   140 positive universal or negative existential. The tactic has to be
   141 invoked by hand and can be a little bit slow. In particular, the
   142 running time is exponential in the number of occurrences of `min' and
   143 `max', and `-' on `nat'.
   144 
   145 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   146 (negated) (in)equalities among the premises and the conclusion into
   147 account (i.e. no compound formulae) and does not know about `min' and
   148 `max', and `-' on `nat'. It is fast and is used automatically by the
   149 simplifier.
   150 
   151 NB: At the moment, these decision procedures do not cope with mixed
   152 nat/int formulae where the two parts interact, such as `m < n ==>
   153 int(m) < int(n)'.
   154 
   155 * HOL/Numeral provides a generic theory of numerals (encoded
   156 efficiently as bit strings); setup for types nat/int/real is in place;
   157 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   158 int, existing theories and proof scripts may require a few additional
   159 type constraints;
   160 
   161 * integer division and remainder can now be performed on constant
   162 arguments;
   163 
   164 * many properties of integer multiplication, division and remainder
   165 are now available;
   166 
   167 * An interface to the Stanford Validity Checker (SVC) is available through the
   168 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   169 are proved automatically.  SVC must be installed separately, and its results
   170 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   171 invocation of the underlying oracle).  For SVC see
   172   http://verify.stanford.edu/SVC
   173 
   174 * IsaMakefile: the HOL-Real target now builds an actual image;
   175 
   176 
   177 ** HOL misc **
   178 
   179 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   180 (in Isabelle/Isar) -- by Gertrud Bauer;
   181 
   182 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   183 analysis for assembly languages with subtypes;
   184 
   185 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   186 -- avoids syntactic ambiguities and treats state, transition, and
   187 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   188 changed syntax and (many) tactics;
   189 
   190 * HOL/inductive: Now also handles more general introduction rules such
   191   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   192   theorems are now maintained within the theory (maintained via the
   193   "mono" attribute);
   194 
   195 * HOL/datatype: Now also handles arbitrarily branching datatypes
   196   (using function types) such as
   197 
   198   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   199 
   200 * HOL/record: record_simproc (part of the default simpset) takes care
   201 of selectors applied to updated records; record_split_tac is no longer
   202 part of the default claset; update_defs may now be removed from the
   203 simpset in many cases; COMPATIBILITY: old behavior achieved by
   204 
   205   claset_ref () := claset() addSWrapper record_split_wrapper;
   206   Delsimprocs [record_simproc]
   207 
   208 * HOL/typedef: fixed type inference for representing set; type
   209 arguments now have to occur explicitly on the rhs as type constraints;
   210 
   211 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   212 names rather than an ML expression;
   213 
   214 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   215 supplied later.  Program schemes can be defined, such as
   216     "While B C s = (if B s then While B C (C s) else s)"
   217 where the well-founded relation can be chosen after B and C have been given.
   218 
   219 * HOL/List: the constructors of type list are now Nil and Cons;
   220 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   221 course, ML tools referring to List.list.op # etc. have to be adapted;
   222 
   223 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   224 disabled by default; run isabelle with option -m HOL to get back to
   225 the original Gordon/HOL-style output;
   226 
   227 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   228 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   229 
   230 * HOL basic syntax simplified (more orthogonal): all variants of
   231 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   232 Eps operator is provided as well: "SOME x. P[x]";
   233 
   234 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   235 
   236 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   237 thus available for user theories;
   238 
   239 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   240 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   241 time;
   242 
   243 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec several
   244   times and then mp
   245 
   246 
   247 *** LK ***
   248 
   249 * the notation <<...>> is now available as a notation for sequences of
   250 formulas;
   251 
   252 * the simplifier is now installed
   253 
   254 * the axiom system has been generalized (thanks to Soren Heilmann) 
   255 
   256 * the classical reasoner now has a default rule database
   257 
   258 
   259 *** ZF ***
   260 
   261 * new primrec section allows primitive recursive functions to be given
   262 directly (as in HOL) over datatypes and the natural numbers;
   263 
   264 * new tactics induct_tac and exhaust_tac for induction (or case
   265 analysis) over datatypes and the natural numbers;
   266 
   267 * the datatype declaration of type T now defines the recursor T_rec;
   268 
   269 * simplification automatically does freeness reasoning for datatype
   270 constructors;
   271 
   272 * automatic type-inference, with AddTCs command to insert new
   273 type-checking rules;
   274 
   275 * datatype introduction rules are now added as Safe Introduction rules
   276 to the claset;
   277 
   278 * the syntax "if P then x else y" is now available in addition to
   279 if(P,x,y);
   280 
   281 
   282 *** Internal programming interfaces ***
   283 
   284 * structures Vartab / Termtab (instances of TableFun) offer efficient
   285 tables indexed by indexname_ord / term_ord (compatible with aconv);
   286 
   287 * AxClass.axclass_tac lost the theory argument;
   288 
   289 * tuned current_goals_markers semantics: begin / end goal avoids
   290 printing empty lines;
   291 
   292 * removed prs and prs_fn hook, which was broken because it did not
   293 include \n in its semantics, forcing writeln to add one
   294 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   295 string -> unit if you really want to output text without newline;
   296 
   297 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   298 plain output, interface builders may have to enable 'isabelle_font'
   299 mode to get Isabelle font glyphs as before;
   300 
   301 * refined token_translation interface; INCOMPATIBILITY: output length
   302 now of type real instead of int;
   303 
   304 * theory loader actions may be traced via new ThyInfo.add_hook
   305 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   306 your own database of information attached to *whole* theories -- as
   307 opposed to intra-theory data slots offered via TheoryDataFun;
   308 
   309 * proper handling of dangling sort hypotheses (at last!);
   310 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   311 extra sort hypotheses that can be witnessed from the type signature;
   312 the force_strip_shyps is gone, any remaining shyps are simply left in
   313 the theorem (with a warning issued by strip_shyps_warning);
   314 
   315 
   316 
   317 New in Isabelle98-1 (October 1998)
   318 ----------------------------------
   319 
   320 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   321 
   322 * several changes of automated proof tools;
   323 
   324 * HOL: major changes to the inductive and datatype packages, including
   325 some minor incompatibilities of theory syntax;
   326 
   327 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   328 called `inj_on';
   329 
   330 * HOL: removed duplicate thms in Arith:
   331   less_imp_add_less  should be replaced by  trans_less_add1
   332   le_imp_add_le      should be replaced by  trans_le_add1
   333 
   334 * HOL: unary minus is now overloaded (new type constraints may be
   335 required);
   336 
   337 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   338 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   339 now taken as an integer constant.
   340 
   341 * Pure: ML function 'theory_of' renamed to 'theory';
   342 
   343 
   344 *** Proof tools ***
   345 
   346 * Simplifier:
   347   1. Asm_full_simp_tac is now more aggressive.
   348      1. It will sometimes reorient premises if that increases their power to
   349         simplify.
   350      2. It does no longer proceed strictly from left to right but may also
   351         rotate premises to achieve further simplification.
   352      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   353      old Asm_full_simp_tac in that it does not rotate premises.
   354   2. The simplifier now knows a little bit about nat-arithmetic.
   355 
   356 * Classical reasoner: wrapper mechanism for the classical reasoner now
   357 allows for selected deletion of wrappers, by introduction of names for
   358 wrapper functionals.  This implies that addbefore, addSbefore,
   359 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   360 and that adding two tactics with the same name overwrites the first
   361 one (emitting a warning).
   362   type wrapper = (int -> tactic) -> (int -> tactic)
   363   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   364   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   365   delWrapper, delSWrapper: claset *  string            -> claset
   366   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   367 
   368 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   369 semantics; addbefore now affects only the unsafe part of step_tac
   370 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   371 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   372 by Force_tac;
   373 
   374 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   375 compWrapper; added safe wrapper (and access functions for it);
   376 
   377 * HOL/split_all_tac is now much faster and fails if there is nothing
   378 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   379 and the names of the automatically generated variables have changed.
   380 split_all_tac has moved within claset() from unsafe wrappers to safe
   381 wrappers, which means that !!-bound variables are split much more
   382 aggressively, and safe_tac and clarify_tac now split such variables.
   383 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   384 Note: the same holds for record_split_tac, which does the job of
   385 split_all_tac for record fields.
   386 
   387 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   388 permanently to the default simpset using Addsplits just like
   389 Addsimps. They can be removed via Delsplits just like
   390 Delsimps. Lower-case versions are also available.
   391 
   392 * HOL/Simplifier: The rule split_if is now part of the default
   393 simpset. This means that the simplifier will eliminate all occurrences
   394 of if-then-else in the conclusion of a goal. To prevent this, you can
   395 either remove split_if completely from the default simpset by
   396 `Delsplits [split_if]' or remove it in a specific call of the
   397 simplifier using `... delsplits [split_if]'.  You can also add/delete
   398 other case splitting rules to/from the default simpset: every datatype
   399 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   400 t is the name of the datatype).
   401 
   402 * Classical reasoner / Simplifier combination: new force_tac (and
   403 derivatives Force_tac, force) combines rewriting and classical
   404 reasoning (and whatever other tools) similarly to auto_tac, but is
   405 aimed to solve the given subgoal completely.
   406 
   407 
   408 *** General ***
   409 
   410 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   411 and `goalw': the theory is no longer needed as an explicit argument -
   412 the current theory context is used; assumptions are no longer returned
   413 at the ML-level unless one of them starts with ==> or !!; it is
   414 recommended to convert to these new commands using isatool fixgoal
   415 (backup your sources first!);
   416 
   417 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   418 the current theory context, and 'theory' to lookup stored theories;
   419 
   420 * new theory section 'locale' for declaring constants, assumptions and
   421 definitions that have local scope;
   422 
   423 * new theory section 'nonterminals' for purely syntactic types;
   424 
   425 * new theory section 'setup' for generic ML setup functions
   426 (e.g. package initialization);
   427 
   428 * the distribution now includes Isabelle icons: see
   429 lib/logo/isabelle-{small,tiny}.xpm;
   430 
   431 * isatool install - install binaries with absolute references to
   432 ISABELLE_HOME/bin;
   433 
   434 * isatool logo -- create instances of the Isabelle logo (as EPS);
   435 
   436 * print mode 'emacs' reserved for Isamode;
   437 
   438 * support multiple print (ast) translations per constant name;
   439 
   440 * theorems involving oracles are now printed with a suffixed [!];
   441 
   442 
   443 *** HOL ***
   444 
   445 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   446 
   447 * HOL/inductive package reorganized and improved: now supports mutual
   448 definitions such as
   449 
   450   inductive EVEN ODD
   451     intrs
   452       null "0 : EVEN"
   453       oddI "n : EVEN ==> Suc n : ODD"
   454       evenI "n : ODD ==> Suc n : EVEN"
   455 
   456 new theorem list "elims" contains an elimination rule for each of the
   457 recursive sets; inductive definitions now handle disjunctive premises
   458 correctly (also ZF);
   459 
   460 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   461 "mutual_induct" no longer exists - the induction rule is always
   462 contained in "induct";
   463 
   464 
   465 * HOL/datatype package re-implemented and greatly improved: now
   466 supports mutually recursive datatypes such as
   467 
   468   datatype
   469     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   470             | SUM ('a aexp) ('a aexp)
   471             | DIFF ('a aexp) ('a aexp)
   472             | NUM 'a
   473   and
   474     'a bexp = LESS ('a aexp) ('a aexp)
   475             | AND ('a bexp) ('a bexp)
   476             | OR ('a bexp) ('a bexp)
   477 
   478 as well as indirectly recursive datatypes such as
   479 
   480   datatype
   481     ('a, 'b) term = Var 'a
   482                   | App 'b ((('a, 'b) term) list)
   483 
   484 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   485 induction on mutually / indirectly recursive datatypes.
   486 
   487 Primrec equations are now stored in theory and can be accessed via
   488 <function_name>.simps.
   489 
   490 INCOMPATIBILITIES:
   491 
   492   - Theories using datatypes must now have theory Datatype as an
   493     ancestor.
   494   - The specific <typename>.induct_tac no longer exists - use the
   495     generic induct_tac instead.
   496   - natE has been renamed to nat.exhaust - use exhaust_tac
   497     instead of res_inst_tac ... natE. Note that the variable
   498     names in nat.exhaust differ from the names in natE, this
   499     may cause some "fragile" proofs to fail.
   500   - The theorems split_<typename>_case and split_<typename>_case_asm
   501     have been renamed to <typename>.split and <typename>.split_asm.
   502   - Since default sorts of type variables are now handled correctly,
   503     some datatype definitions may have to be annotated with explicit
   504     sort constraints.
   505   - Primrec definitions no longer require function name and type
   506     of recursive argument.
   507 
   508 Consider using isatool fixdatatype to adapt your theories and proof
   509 scripts to the new package (backup your sources first!).
   510 
   511 
   512 * HOL/record package: considerably improved implementation; now
   513 includes concrete syntax for record types, terms, updates; theorems
   514 for surjective pairing and splitting !!-bound record variables; proof
   515 support is as follows:
   516 
   517   1) standard conversions (selectors or updates applied to record
   518 constructor terms) are part of the standard simpset;
   519 
   520   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   521 made part of standard simpset and claset via addIffs;
   522 
   523   3) a tactic for record field splitting (record_split_tac) is part of
   524 the standard claset (addSWrapper);
   525 
   526 To get a better idea about these rules you may retrieve them via
   527 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   528 the name of your record type.
   529 
   530 The split tactic 3) conceptually simplifies by the following rule:
   531 
   532   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   533 
   534 Thus any record variable that is bound by meta-all will automatically
   535 blow up into some record constructor term, consequently the
   536 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   537 solve record problems automatically.
   538 
   539 
   540 * reorganized the main HOL image: HOL/Integ and String loaded by
   541 default; theory Main includes everything;
   542 
   543 * automatic simplification of integer sums and comparisons, using cancellation;
   544 
   545 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   546 
   547 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   548 
   549 * many new identities for unions, intersections, set difference, etc.;
   550 
   551 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   552 called split_if, split_split, split_sum_case and split_nat_case (to go
   553 with add/delsplits);
   554 
   555 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   556 (?x::unit) = (); this is made part of the default simpset, which COULD
   557 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   558 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   559 unit_abs_eta_conv is added in order to counter the effect of
   560 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   561 %u.f();
   562 
   563 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   564 makes more sense);
   565 
   566 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   567   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   568   disjointness reasoning but breaking a few old proofs.
   569 
   570 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   571 to 'converse' from 'inverse' (for compatibility with ZF and some
   572 literature);
   573 
   574 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   575 the well-founded relation;
   576 
   577 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   578     Compl A.  The "Compl" syntax remains available as input syntax for this
   579     release ONLY.
   580 
   581 * HOL/Update: new theory of function updates:
   582     f(a:=b) == %x. if x=a then b else f x
   583 may also be iterated as in f(a:=b,c:=d,...);
   584 
   585 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   586 
   587 * HOL/List:
   588   - new function list_update written xs[i:=v] that updates the i-th
   589     list position. May also be iterated as in xs[i:=a,j:=b,...].
   590   - new function `upt' written [i..j(] which generates the list
   591     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   592     bound write [i..j], which is a shorthand for [i..j+1(].
   593   - new lexicographic orderings and corresponding wellfoundedness theorems.
   594 
   595 * HOL/Arith:
   596   - removed 'pred' (predecessor) function;
   597   - generalized some theorems about n-1;
   598   - many new laws about "div" and "mod";
   599   - new laws about greatest common divisors (see theory ex/Primes);
   600 
   601 * HOL/Relation: renamed the relational operator r^-1 "converse"
   602 instead of "inverse";
   603 
   604 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   605   of the multiset ordering;
   606 
   607 * directory HOL/Real: a construction of the reals using Dedekind cuts
   608   (not included by default);
   609 
   610 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   611 
   612 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   613   programs, i.e. different program variables may have different types.
   614 
   615 * calling (stac rew i) now fails if "rew" has no effect on the goal
   616   [previously, this check worked only if the rewrite rule was unconditional]
   617   Now rew can involve either definitions or equalities (either == or =).
   618 
   619 
   620 *** ZF ***
   621 
   622 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   623   only the theorems proved on ZF.ML;
   624 
   625 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   626   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   627   disjointness reasoning but breaking a few old proofs.
   628 
   629 * ZF/Update: new theory of function updates
   630     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   631   may also be iterated as in f(a:=b,c:=d,...);
   632 
   633 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   634 
   635 * calling (stac rew i) now fails if "rew" has no effect on the goal
   636   [previously, this check worked only if the rewrite rule was unconditional]
   637   Now rew can involve either definitions or equalities (either == or =).
   638 
   639 * case_tac provided for compatibility with HOL
   640     (like the old excluded_middle_tac, but with subgoals swapped)
   641 
   642 
   643 *** Internal programming interfaces ***
   644 
   645 * Pure: several new basic modules made available for general use, see
   646 also src/Pure/README;
   647 
   648 * improved the theory data mechanism to support encapsulation (data
   649 kind name replaced by private Object.kind, acting as authorization
   650 key); new type-safe user interface via functor TheoryDataFun; generic
   651 print_data function becomes basically useless;
   652 
   653 * removed global_names compatibility flag -- all theory declarations
   654 are qualified by default;
   655 
   656 * module Pure/Syntax now offers quote / antiquote translation
   657 functions (useful for Hoare logic etc. with implicit dependencies);
   658 see HOL/ex/Antiquote for an example use;
   659 
   660 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   661 cterm -> thm;
   662 
   663 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   664 subgoal;
   665 
   666 * Display.print_goals function moved to Locale.print_goals;
   667 
   668 * standard print function for goals supports current_goals_markers
   669 variable for marking begin of proof, end of proof, start of goal; the
   670 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   671 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   672 for example;
   673 
   674 
   675 
   676 New in Isabelle98 (January 1998)
   677 --------------------------------
   678 
   679 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   680 
   681 * changed lexical syntax of terms / types: dots made part of long
   682 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   683 
   684 * simpset (and claset) reference variable replaced by functions
   685 simpset / simpset_ref;
   686 
   687 * no longer supports theory aliases (via merge) and non-trivial
   688 implicit merge of thms' signatures;
   689 
   690 * most internal names of constants changed due to qualified names;
   691 
   692 * changed Pure/Sequence interface (see Pure/seq.ML);
   693 
   694 
   695 *** General Changes ***
   696 
   697 * hierachically structured name spaces (for consts, types, axms, thms
   698 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   699 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   700 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   701 long_names for fully qualified output names; NOTE: ML programs
   702 (special tactics, packages etc.) referring to internal names may have
   703 to be adapted to cope with fully qualified names; in case of severe
   704 backward campatibility problems try setting 'global_names' at compile
   705 time to have enrything declared within a flat name space; one may also
   706 fine tune name declarations in theories via the 'global' and 'local'
   707 section;
   708 
   709 * reimplemented the implicit simpset and claset using the new anytype
   710 data filed in signatures; references simpset:simpset ref etc. are
   711 replaced by functions simpset:unit->simpset and
   712 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   713 to patch your ML files accordingly;
   714 
   715 * HTML output now includes theory graph data for display with Java
   716 applet or isatool browser; data generated automatically via isatool
   717 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   718 
   719 * defs may now be conditional; improved rewrite_goals_tac to handle
   720 conditional equations;
   721 
   722 * defs now admits additional type arguments, using TYPE('a) syntax;
   723 
   724 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   725 creates a new theory node; implicit merge of thms' signatures is
   726 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   727 transfer:theory->thm->thm in (rare) cases;
   728 
   729 * improved handling of draft signatures / theories; draft thms (and
   730 ctyps, cterms) are automatically promoted to real ones;
   731 
   732 * slightly changed interfaces for oracles: admit many per theory, named
   733 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   734 
   735 * print_goals: optional output of const types (set show_consts and
   736 show_types);
   737 
   738 * improved output of warnings (###) and errors (***);
   739 
   740 * subgoal_tac displays a warning if the new subgoal has type variables;
   741 
   742 * removed old README and Makefiles;
   743 
   744 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   745 
   746 * removed obsolete init_pps and init_database;
   747 
   748 * deleted the obsolete tactical STATE, which was declared by
   749     fun STATE tacfun st = tacfun st st;
   750 
   751 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   752 (which abbreviates $HOME);
   753 
   754 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   755 use isatool fixseq to adapt your ML programs (this works for fully
   756 qualified references to the Sequence structure only!);
   757 
   758 * use_thy no longer requires writable current directory; it always
   759 reloads .ML *and* .thy file, if either one is out of date;
   760 
   761 
   762 *** Classical Reasoner ***
   763 
   764 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   765 tactics that use classical reasoning to simplify a subgoal without
   766 splitting it into several subgoals;
   767 
   768 * Safe_tac: like safe_tac but uses the default claset;
   769 
   770 
   771 *** Simplifier ***
   772 
   773 * added simplification meta rules:
   774     (asm_)(full_)simplify: simpset -> thm -> thm;
   775 
   776 * simplifier.ML no longer part of Pure -- has to be loaded by object
   777 logics (again);
   778 
   779 * added prems argument to simplification procedures;
   780 
   781 * HOL, FOL, ZF: added infix function `addsplits':
   782   instead of `<simpset> setloop (split_tac <thms>)'
   783   you can simply write `<simpset> addsplits <thms>'
   784 
   785 
   786 *** Syntax ***
   787 
   788 * TYPE('a) syntax for type reflection terms;
   789 
   790 * no longer handles consts with name "" -- declare as 'syntax' instead;
   791 
   792 * pretty printer: changed order of mixfix annotation preference (again!);
   793 
   794 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   795 
   796 
   797 *** HOL ***
   798 
   799 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   800   with `addloop' of the simplifier to faciliate case splitting in premises.
   801 
   802 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   803 
   804 * HOL/Auth: new protocol proofs including some for the Internet
   805   protocol TLS;
   806 
   807 * HOL/Map: new theory of `maps' a la VDM;
   808 
   809 * HOL/simplifier: simplification procedures nat_cancel_sums for
   810 cancelling out common nat summands from =, <, <= (in)equalities, or
   811 differences; simplification procedures nat_cancel_factor for
   812 cancelling common factor from =, <, <= (in)equalities over natural
   813 sums; nat_cancel contains both kinds of procedures, it is installed by
   814 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   815 
   816 * HOL/simplifier: terms of the form
   817   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   818   are rewritten to
   819   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   820   and those of the form
   821   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   822   are rewritten to
   823   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   824 
   825 * HOL/datatype
   826   Each datatype `t' now comes with a theorem `split_t_case' of the form
   827 
   828   P(t_case f1 ... fn x) =
   829      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   830         ...
   831        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   832      )
   833 
   834   and a theorem `split_t_case_asm' of the form
   835 
   836   P(t_case f1 ... fn x) =
   837     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   838         ...
   839        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   840      )
   841   which can be added to a simpset via `addsplits'. The existing theorems
   842   expand_list_case and expand_option_case have been renamed to
   843   split_list_case and split_option_case.
   844 
   845 * HOL/Arithmetic:
   846   - `pred n' is automatically converted to `n-1'.
   847     Users are strongly encouraged not to use `pred' any longer,
   848     because it will disappear altogether at some point.
   849   - Users are strongly encouraged to write "0 < n" rather than
   850     "n ~= 0". Theorems and proof tools have been modified towards this
   851     `standard'.
   852 
   853 * HOL/Lists:
   854   the function "set_of_list" has been renamed "set" (and its theorems too);
   855   the function "nth" now takes its arguments in the reverse order and
   856   has acquired the infix notation "!" as in "xs!n".
   857 
   858 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   859 
   860 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   861   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   862 
   863 * HOL/record: extensible records with schematic structural subtyping
   864 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   865 still lacks various theorems and concrete record syntax;
   866 
   867 
   868 *** HOLCF ***
   869 
   870 * removed "axioms" and "generated by" sections;
   871 
   872 * replaced "ops" section by extended "consts" section, which is capable of
   873   handling the continuous function space "->" directly;
   874 
   875 * domain package:
   876   . proves theorems immediately and stores them in the theory,
   877   . creates hierachical name space,
   878   . now uses normal mixfix annotations (instead of cinfix...),
   879   . minor changes to some names and values (for consistency),
   880   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   881   . separator between mutual domain defs: changed "," to "and",
   882   . improved handling of sort constraints;  now they have to
   883     appear on the left-hand side of the equations only;
   884 
   885 * fixed LAM <x,y,zs>.b syntax;
   886 
   887 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   888 adm (%x. P (t x)), where P is chainfinite and t continuous;
   889 
   890 
   891 *** FOL and ZF ***
   892 
   893 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   894   with `addloop' of the simplifier to faciliate case splitting in premises.
   895 
   896 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   897 in HOL, they strip ALL and --> from proved theorems;
   898 
   899 
   900 
   901 New in Isabelle94-8 (May 1997)
   902 ------------------------------
   903 
   904 *** General Changes ***
   905 
   906 * new utilities to build / run / maintain Isabelle etc. (in parts
   907 still somewhat experimental); old Makefiles etc. still functional;
   908 
   909 * new 'Isabelle System Manual';
   910 
   911 * INSTALL text, together with ./configure and ./build scripts;
   912 
   913 * reimplemented type inference for greater efficiency, better error
   914 messages and clean internal interface;
   915 
   916 * prlim command for dealing with lots of subgoals (an easier way of
   917 setting goals_limit);
   918 
   919 
   920 *** Syntax ***
   921 
   922 * supports alternative (named) syntax tables (parser and pretty
   923 printer); internal interface is provided by add_modesyntax(_i);
   924 
   925 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   926 be used in conjunction with the Isabelle symbol font; uses the
   927 "symbols" syntax table;
   928 
   929 * added token_translation interface (may translate name tokens in
   930 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   931 the current print_mode); IMPORTANT: user print translation functions
   932 are responsible for marking newly introduced bounds
   933 (Syntax.mark_boundT);
   934 
   935 * token translations for modes "xterm" and "xterm_color" that display
   936 names in bold, underline etc. or colors (which requires a color
   937 version of xterm);
   938 
   939 * infixes may now be declared with names independent of their syntax;
   940 
   941 * added typed_print_translation (like print_translation, but may
   942 access type of constant);
   943 
   944 
   945 *** Classical Reasoner ***
   946 
   947 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
   948 some limitations.  Blast_tac...
   949   + ignores addss, addbefore, addafter; this restriction is intrinsic
   950   + ignores elimination rules that don't have the correct format
   951         (the conclusion MUST be a formula variable)
   952   + ignores types, which can make HOL proofs fail
   953   + rules must not require higher-order unification, e.g. apply_type in ZF
   954     [message "Function Var's argument not a bound variable" relates to this]
   955   + its proof strategy is more general but can actually be slower
   956 
   957 * substitution with equality assumptions no longer permutes other
   958 assumptions;
   959 
   960 * minor changes in semantics of addafter (now called addaltern); renamed
   961 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
   962 (and access functions for it);
   963 
   964 * improved combination of classical reasoner and simplifier:
   965   + functions for handling clasimpsets
   966   + improvement of addss: now the simplifier is called _after_ the
   967     safe steps.
   968   + safe variant of addss called addSss: uses safe simplifications
   969     _during_ the safe steps. It is more complete as it allows multiple
   970     instantiations of unknowns (e.g. with slow_tac).
   971 
   972 *** Simplifier ***
   973 
   974 * added interface for simplification procedures (functions that
   975 produce *proven* rewrite rules on the fly, depending on current
   976 redex);
   977 
   978 * ordering on terms as parameter (used for ordered rewriting);
   979 
   980 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
   981 
   982 * the solver is now split into a safe and an unsafe part.
   983 This should be invisible for the normal user, except that the
   984 functions setsolver and addsolver have been renamed to setSolver and
   985 addSolver; added safe_asm_full_simp_tac;
   986 
   987 
   988 *** HOL ***
   989 
   990 * a generic induction tactic `induct_tac' which works for all datatypes and
   991 also for type `nat';
   992 
   993 * a generic case distinction tactic `exhaust_tac' which works for all
   994 datatypes and also for type `nat';
   995 
   996 * each datatype comes with a function `size';
   997 
   998 * patterns in case expressions allow tuple patterns as arguments to
   999 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1000 
  1001 * primrec now also works with type nat;
  1002 
  1003 * recdef: a new declaration form, allows general recursive functions to be
  1004 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1005 
  1006 * the constant for negation has been renamed from "not" to "Not" to
  1007 harmonize with FOL, ZF, LK, etc.;
  1008 
  1009 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1010 infinite lists;
  1011 
  1012 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1013 
  1014 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1015 problems in commutative rings, using axiomatic type classes for + and *;
  1016 
  1017 * more examples in HOL/MiniML and HOL/Auth;
  1018 
  1019 * more default rewrite rules for quantifiers, union/intersection;
  1020 
  1021 * a new constant `arbitrary == @x.False';
  1022 
  1023 * HOLCF/IOA replaces old HOL/IOA;
  1024 
  1025 * HOLCF changes: derived all rules and arities
  1026   + axiomatic type classes instead of classes
  1027   + typedef instead of faking type definitions
  1028   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1029   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1030   + eliminated the types void, one, tr
  1031   + use unit lift and bool lift (with translations) instead of one and tr
  1032   + eliminated blift from Lift3.thy (use Def instead of blift)
  1033   all eliminated rules are derived as theorems --> no visible changes ;
  1034 
  1035 
  1036 *** ZF ***
  1037 
  1038 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1039 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1040 as ZF_cs addSIs [equalityI];
  1041 
  1042 
  1043 
  1044 New in Isabelle94-7 (November 96)
  1045 ---------------------------------
  1046 
  1047 * allowing negative levels (as offsets) in prlev and choplev;
  1048 
  1049 * super-linear speedup for large simplifications;
  1050 
  1051 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1052 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1053 FAIL); can suppress it using the command Delsimps (ex_simps @
  1054 all_simps); De Morgan laws are also now included, by default;
  1055 
  1056 * improved printing of ==>  :  ~:
  1057 
  1058 * new object-logic "Sequents" adds linear logic, while replacing LK
  1059 and Modal (thanks to Sara Kalvala);
  1060 
  1061 * HOL/Auth: correctness proofs for authentication protocols;
  1062 
  1063 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1064 examples on HOL/Auth);
  1065 
  1066 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1067 the rewriter and classical reasoner simultaneously;
  1068 
  1069 * function uresult no longer returns theorems in "standard" format;
  1070 regain previous version by: val uresult = standard o uresult;
  1071 
  1072 
  1073 
  1074 New in Isabelle94-6
  1075 -------------------
  1076 
  1077 * oracles -- these establish an interface between Isabelle and trusted
  1078 external reasoners, which may deliver results as theorems;
  1079 
  1080 * proof objects (in particular record all uses of oracles);
  1081 
  1082 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1083 
  1084 * "constdefs" section in theory files;
  1085 
  1086 * "primrec" section (HOL) no longer requires names;
  1087 
  1088 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1089 
  1090 
  1091 
  1092 New in Isabelle94-5
  1093 -------------------
  1094 
  1095 * reduced space requirements;
  1096 
  1097 * automatic HTML generation from theories;
  1098 
  1099 * theory files no longer require "..." (quotes) around most types;
  1100 
  1101 * new examples, including two proofs of the Church-Rosser theorem;
  1102 
  1103 * non-curried (1994) version of HOL is no longer distributed;
  1104 
  1105 
  1106 
  1107 New in Isabelle94-4
  1108 -------------------
  1109 
  1110 * greatly reduced space requirements;
  1111 
  1112 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1113 
  1114 * searchable theorem database (see the section "Retrieving theorems" on
  1115 page 8 of the Reference Manual);
  1116 
  1117 * new examples, including Grabczewski's monumental case study of the
  1118 Axiom of Choice;
  1119 
  1120 * The previous version of HOL renamed to Old_HOL;
  1121 
  1122 * The new version of HOL (previously called CHOL) uses a curried syntax
  1123 for functions.  Application looks like f a b instead of f(a,b);
  1124 
  1125 * Mutually recursive inductive definitions finally work in HOL;
  1126 
  1127 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1128 translates to the operator "split";
  1129 
  1130 
  1131 
  1132 New in Isabelle94-3
  1133 -------------------
  1134 
  1135 * new infix operator, addss, allowing the classical reasoner to
  1136 perform simplification at each step of its search.  Example:
  1137         fast_tac (cs addss ss)
  1138 
  1139 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1140 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1141 look like (a,b) instead of <a,b>;
  1142 
  1143 * PLEASE NOTE: CHOL will eventually replace HOL!
  1144 
  1145 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1146 It translates to the operator "split".  A new theory of integers is available;
  1147 
  1148 * In ZF, integer numerals now denote two's-complement binary integers.
  1149 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1150 
  1151 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1152 of the Axiom of Choice;
  1153 
  1154 
  1155 
  1156 New in Isabelle94-2
  1157 -------------------
  1158 
  1159 * Significantly faster resolution;
  1160 
  1161 * the different sections in a .thy file can now be mixed and repeated
  1162 freely;
  1163 
  1164 * Database of theorems for FOL, HOL and ZF.  New
  1165 commands including qed, qed_goal and bind_thm store theorems in the database.
  1166 
  1167 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1168 a given theory (thms_of), or find out what theory a theorem was proved in
  1169 (theory_of_thm);
  1170 
  1171 * Bugs fixed in the inductive definition and datatype packages;
  1172 
  1173 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1174 and HOL_dup_cs obsolete;
  1175 
  1176 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1177 have been removed;
  1178 
  1179 * Simpler definition of function space in ZF;
  1180 
  1181 * new results about cardinal and ordinal arithmetic in ZF;
  1182 
  1183 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1184 types;
  1185 
  1186 
  1187 $Id$