NEWS
author nipkow
Mon Mar 13 13:13:46 2000 +0100 (2000-03-13)
changeset 8425 f03c667cf702
parent 8412 65f9089f6f71
child 8440 d66f0f14b1ca
permissions -rw-r--r--
*** empty log message ***
     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 constant for f``x is now "image" rather than "op ``".
    11 
    12 
    13 *** Isabelle document preparation ***
    14 
    15 * isatool mkdir provides easy setup of Isabelle session directories,
    16 including proper documents;
    17 
    18 * generated LaTeX sources are now deleted after successful run
    19 (isatool document -c); may retain a copy somewhere else via -D option
    20 of isatool usedir;
    21 
    22 * old-style theories now produce (crude) LaTeX sources as well;
    23 
    24 
    25 *** Isar ***
    26 
    27 * names of theorems etc. may be natural numbers as well;
    28 
    29 * intro/elim/dest attributes: changed ! / !! flags to ? / ??;
    30 
    31 * Pure now provides its own version of intro/elim/dest attributes;
    32 useful for building new logics, but beware of confusion with the
    33 Provers/classical ones!
    34 
    35 * new 'obtain' language element supports generalized existence proofs;
    36 
    37 * HOL: removed "case_split" thm binding, should use "cases" proof
    38 method anyway;
    39 
    40 * tuned syntax of "induct" method;
    41 
    42 * new "cases" method for propositions, inductive sets and types;
    43 
    44 
    45 *** HOL ***
    46 
    47 * Algebra: new theory of rings and univariate polynomials, by Clemens
    48 Ballarin;
    49 
    50 * HOL/record: fixed select-update simplification procedure to handle
    51 extended records as well; admit "r" as field name;
    52 
    53 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
    54 Arithmetic, by Thomas M Rasmussen;
    55 
    56 * There is a new tactic "cases_tac" for case distinctions; it subsumes the
    57 old "case_tac" and "exhaust_tac" (which should no longer be used).
    58 
    59 *** General ***
    60 
    61 * compression of ML heaps images may now be controlled via -c option
    62 of isabelle and isatool usedir;
    63 
    64 
    65 
    66 New in Isabelle99 (October 1999)
    67 --------------------------------
    68 
    69 *** Overview of INCOMPATIBILITIES (see below for more details) ***
    70 
    71 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
    72 are no longer simplified.  (This allows the simplifier to unfold recursive
    73 functional programs.)  To restore the old behaviour, declare
    74 
    75     Delcongs [if_weak_cong];
    76 
    77 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    78 complement;
    79 
    80 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    81 
    82 * HOL/datatype: mutual_induct_tac no longer exists --
    83   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
    84 
    85 * HOL/typedef: fixed type inference for representing set; type
    86 arguments now have to occur explicitly on the rhs as type constraints;
    87 
    88 * ZF: The con_defs part of an inductive definition may no longer refer
    89 to constants declared in the same theory;
    90 
    91 * HOL, ZF: the function mk_cases, generated by the inductive
    92 definition package, has lost an argument.  To simplify its result, it
    93 uses the default simpset instead of a supplied list of theorems.
    94 
    95 * HOL/List: the constructors of type list are now Nil and Cons;
    96 
    97 * Simplifier: the type of the infix ML functions
    98 	setSSolver addSSolver setSolver addSolver
    99 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   100 for packaging solvers. A solver is created via
   101 	mk_solver: string -> (thm list -> int -> tactic) -> solver
   102 where the string argument is only a comment.
   103 
   104 
   105 *** Proof tools ***
   106 
   107 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   108 decision procedure for linear arithmetic. Currently it is used for
   109 types `nat', `int', and `real' in HOL (see below); it can, should and
   110 will be instantiated for other types and logics as well.
   111 
   112 * The simplifier now accepts rewrite rules with flexible heads, eg
   113      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   114   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   115   matching.
   116 
   117 
   118 *** General ***
   119 
   120 * New Isabelle/Isar subsystem provides an alternative to traditional
   121 tactical theorem proving; together with the ProofGeneral/isar user
   122 interface it offers an interactive environment for developing human
   123 readable proof documents (Isar == Intelligible semi-automated
   124 reasoning); for further information see isatool doc isar-ref,
   125 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   126 
   127 * improved presentation of theories: better HTML markup (including
   128 colors), graph views in several sizes; isatool usedir now provides a
   129 proper interface for user theories (via -P option); actual document
   130 preparation based on (PDF)LaTeX is available as well (for new-style
   131 theories only); see isatool doc system for more information;
   132 
   133 * native support for Proof General, both for classic Isabelle and
   134 Isabelle/Isar;
   135 
   136 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   137 using the graph browser tool;
   138 
   139 * Isabelle manuals now also available as PDF;
   140 
   141 * theory loader rewritten from scratch (may not be fully
   142 bug-compatible); old loadpath variable has been replaced by show_path,
   143 add_path, del_path, reset_path functions; new operations such as
   144 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   145 isatool doc ref);
   146 
   147 * improved isatool install: option -k creates KDE application icon,
   148 option -p DIR installs standalone binaries;
   149 
   150 * added ML_PLATFORM setting (useful for cross-platform installations);
   151 more robust handling of platform specific ML images for SML/NJ;
   152 
   153 * the settings environment is now statically scoped, i.e. it is never
   154 created again in sub-processes invoked from isabelle, isatool, or
   155 Isabelle;
   156 
   157 * path element specification '~~' refers to '$ISABELLE_HOME';
   158 
   159 * in locales, the "assumes" and "defines" parts may be omitted if
   160 empty;
   161 
   162 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   163 long arrows);
   164 
   165 * new print_mode "HTML";
   166 
   167 * new flag show_tags controls display of tags of theorems (which are
   168 basically just comments that may be attached by some tools);
   169 
   170 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   171 mode and goal output format:
   172 
   173 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   174 244c244
   175 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   176 ---
   177 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   178 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   179 181c181
   180 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   181 ---
   182 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   183 
   184 * function bind_thms stores lists of theorems (cf. bind_thm);
   185 
   186 * new shorthand tactics ftac, eatac, datac, fatac;
   187 
   188 * qed (and friends) now accept "" as result name; in that case the
   189 theorem is not stored, but proper checks and presentation of the
   190 result still apply;
   191 
   192 * theorem database now also indexes constants "Trueprop", "all",
   193 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   194 
   195 
   196 *** HOL ***
   197 
   198 ** HOL arithmetic **
   199 
   200 * There are now decision procedures for linear arithmetic over nat and
   201 int:
   202 
   203 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   204 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   205 are treated as atomic; subformulae not involving type `nat' or `int'
   206 are ignored; quantified subformulae are ignored unless they are
   207 positive universal or negative existential. The tactic has to be
   208 invoked by hand and can be a little bit slow. In particular, the
   209 running time is exponential in the number of occurrences of `min' and
   210 `max', and `-' on `nat'.
   211 
   212 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   213 (negated) (in)equalities among the premises and the conclusion into
   214 account (i.e. no compound formulae) and does not know about `min' and
   215 `max', and `-' on `nat'. It is fast and is used automatically by the
   216 simplifier.
   217 
   218 NB: At the moment, these decision procedures do not cope with mixed
   219 nat/int formulae where the two parts interact, such as `m < n ==>
   220 int(m) < int(n)'.
   221 
   222 * HOL/Numeral provides a generic theory of numerals (encoded
   223 efficiently as bit strings); setup for types nat/int/real is in place;
   224 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   225 int, existing theories and proof scripts may require a few additional
   226 type constraints;
   227 
   228 * integer division and remainder can now be performed on constant
   229 arguments;
   230 
   231 * many properties of integer multiplication, division and remainder
   232 are now available;
   233 
   234 * An interface to the Stanford Validity Checker (SVC) is available through the
   235 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   236 are proved automatically.  SVC must be installed separately, and its results
   237 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   238 invocation of the underlying oracle).  For SVC see
   239   http://verify.stanford.edu/SVC
   240 
   241 * IsaMakefile: the HOL-Real target now builds an actual image;
   242 
   243 
   244 ** HOL misc **
   245 
   246 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   247 (in Isabelle/Isar) -- by Gertrud Bauer;
   248 
   249 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   250 analysis for assembly languages with subtypes;
   251 
   252 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   253 -- avoids syntactic ambiguities and treats state, transition, and
   254 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   255 changed syntax and (many) tactics;
   256 
   257 * HOL/inductive: Now also handles more general introduction rules such
   258   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   259   theorems are now maintained within the theory (maintained via the
   260   "mono" attribute);
   261 
   262 * HOL/datatype: Now also handles arbitrarily branching datatypes
   263   (using function types) such as
   264 
   265   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   266 
   267 * HOL/record: record_simproc (part of the default simpset) takes care
   268 of selectors applied to updated records; record_split_tac is no longer
   269 part of the default claset; update_defs may now be removed from the
   270 simpset in many cases; COMPATIBILITY: old behavior achieved by
   271 
   272   claset_ref () := claset() addSWrapper record_split_wrapper;
   273   Delsimprocs [record_simproc]
   274 
   275 * HOL/typedef: fixed type inference for representing set; type
   276 arguments now have to occur explicitly on the rhs as type constraints;
   277 
   278 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   279 names rather than an ML expression;
   280 
   281 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   282 supplied later.  Program schemes can be defined, such as
   283     "While B C s = (if B s then While B C (C s) else s)"
   284 where the well-founded relation can be chosen after B and C have been given.
   285 
   286 * HOL/List: the constructors of type list are now Nil and Cons;
   287 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   288 course, ML tools referring to List.list.op # etc. have to be adapted;
   289 
   290 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   291 disabled by default; run isabelle with option -m HOL to get back to
   292 the original Gordon/HOL-style output;
   293 
   294 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   295 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   296 
   297 * HOL basic syntax simplified (more orthogonal): all variants of
   298 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   299 Eps operator is provided as well: "SOME x. P[x]";
   300 
   301 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   302 
   303 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   304 thus available for user theories;
   305 
   306 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   307 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   308 time;
   309 
   310 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   311 several times and then mp;
   312 
   313 
   314 *** LK ***
   315 
   316 * the notation <<...>> is now available as a notation for sequences of
   317 formulas;
   318 
   319 * the simplifier is now installed
   320 
   321 * the axiom system has been generalized (thanks to Soren Heilmann) 
   322 
   323 * the classical reasoner now has a default rule database
   324 
   325 
   326 *** ZF ***
   327 
   328 * new primrec section allows primitive recursive functions to be given
   329 directly (as in HOL) over datatypes and the natural numbers;
   330 
   331 * new tactics induct_tac and exhaust_tac for induction (or case
   332 analysis) over datatypes and the natural numbers;
   333 
   334 * the datatype declaration of type T now defines the recursor T_rec;
   335 
   336 * simplification automatically does freeness reasoning for datatype
   337 constructors;
   338 
   339 * automatic type-inference, with AddTCs command to insert new
   340 type-checking rules;
   341 
   342 * datatype introduction rules are now added as Safe Introduction rules
   343 to the claset;
   344 
   345 * the syntax "if P then x else y" is now available in addition to
   346 if(P,x,y);
   347 
   348 
   349 *** Internal programming interfaces ***
   350 
   351 * tuned simplifier trace output; new flag debug_simp;
   352 
   353 * structures Vartab / Termtab (instances of TableFun) offer efficient
   354 tables indexed by indexname_ord / term_ord (compatible with aconv);
   355 
   356 * AxClass.axclass_tac lost the theory argument;
   357 
   358 * tuned current_goals_markers semantics: begin / end goal avoids
   359 printing empty lines;
   360 
   361 * removed prs and prs_fn hook, which was broken because it did not
   362 include \n in its semantics, forcing writeln to add one
   363 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   364 string -> unit if you really want to output text without newline;
   365 
   366 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   367 plain output, interface builders may have to enable 'isabelle_font'
   368 mode to get Isabelle font glyphs as before;
   369 
   370 * refined token_translation interface; INCOMPATIBILITY: output length
   371 now of type real instead of int;
   372 
   373 * theory loader actions may be traced via new ThyInfo.add_hook
   374 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   375 your own database of information attached to *whole* theories -- as
   376 opposed to intra-theory data slots offered via TheoryDataFun;
   377 
   378 * proper handling of dangling sort hypotheses (at last!);
   379 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   380 extra sort hypotheses that can be witnessed from the type signature;
   381 the force_strip_shyps flag is gone, any remaining shyps are simply
   382 left in the theorem (with a warning issued by strip_shyps_warning);
   383 
   384 
   385 
   386 New in Isabelle98-1 (October 1998)
   387 ----------------------------------
   388 
   389 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   390 
   391 * several changes of automated proof tools;
   392 
   393 * HOL: major changes to the inductive and datatype packages, including
   394 some minor incompatibilities of theory syntax;
   395 
   396 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   397 called `inj_on';
   398 
   399 * HOL: removed duplicate thms in Arith:
   400   less_imp_add_less  should be replaced by  trans_less_add1
   401   le_imp_add_le      should be replaced by  trans_le_add1
   402 
   403 * HOL: unary minus is now overloaded (new type constraints may be
   404 required);
   405 
   406 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   407 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   408 now taken as an integer constant.
   409 
   410 * Pure: ML function 'theory_of' renamed to 'theory';
   411 
   412 
   413 *** Proof tools ***
   414 
   415 * Simplifier:
   416   1. Asm_full_simp_tac is now more aggressive.
   417      1. It will sometimes reorient premises if that increases their power to
   418         simplify.
   419      2. It does no longer proceed strictly from left to right but may also
   420         rotate premises to achieve further simplification.
   421      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   422      old Asm_full_simp_tac in that it does not rotate premises.
   423   2. The simplifier now knows a little bit about nat-arithmetic.
   424 
   425 * Classical reasoner: wrapper mechanism for the classical reasoner now
   426 allows for selected deletion of wrappers, by introduction of names for
   427 wrapper functionals.  This implies that addbefore, addSbefore,
   428 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   429 and that adding two tactics with the same name overwrites the first
   430 one (emitting a warning).
   431   type wrapper = (int -> tactic) -> (int -> tactic)
   432   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   433   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   434   delWrapper, delSWrapper: claset *  string            -> claset
   435   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   436 
   437 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   438 semantics; addbefore now affects only the unsafe part of step_tac
   439 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   440 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   441 by Force_tac;
   442 
   443 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   444 compWrapper; added safe wrapper (and access functions for it);
   445 
   446 * HOL/split_all_tac is now much faster and fails if there is nothing
   447 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   448 and the names of the automatically generated variables have changed.
   449 split_all_tac has moved within claset() from unsafe wrappers to safe
   450 wrappers, which means that !!-bound variables are split much more
   451 aggressively, and safe_tac and clarify_tac now split such variables.
   452 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   453 Note: the same holds for record_split_tac, which does the job of
   454 split_all_tac for record fields.
   455 
   456 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   457 permanently to the default simpset using Addsplits just like
   458 Addsimps. They can be removed via Delsplits just like
   459 Delsimps. Lower-case versions are also available.
   460 
   461 * HOL/Simplifier: The rule split_if is now part of the default
   462 simpset. This means that the simplifier will eliminate all occurrences
   463 of if-then-else in the conclusion of a goal. To prevent this, you can
   464 either remove split_if completely from the default simpset by
   465 `Delsplits [split_if]' or remove it in a specific call of the
   466 simplifier using `... delsplits [split_if]'.  You can also add/delete
   467 other case splitting rules to/from the default simpset: every datatype
   468 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   469 t is the name of the datatype).
   470 
   471 * Classical reasoner / Simplifier combination: new force_tac (and
   472 derivatives Force_tac, force) combines rewriting and classical
   473 reasoning (and whatever other tools) similarly to auto_tac, but is
   474 aimed to solve the given subgoal completely.
   475 
   476 
   477 *** General ***
   478 
   479 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   480 and `goalw': the theory is no longer needed as an explicit argument -
   481 the current theory context is used; assumptions are no longer returned
   482 at the ML-level unless one of them starts with ==> or !!; it is
   483 recommended to convert to these new commands using isatool fixgoal
   484 (backup your sources first!);
   485 
   486 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   487 the current theory context, and 'theory' to lookup stored theories;
   488 
   489 * new theory section 'locale' for declaring constants, assumptions and
   490 definitions that have local scope;
   491 
   492 * new theory section 'nonterminals' for purely syntactic types;
   493 
   494 * new theory section 'setup' for generic ML setup functions
   495 (e.g. package initialization);
   496 
   497 * the distribution now includes Isabelle icons: see
   498 lib/logo/isabelle-{small,tiny}.xpm;
   499 
   500 * isatool install - install binaries with absolute references to
   501 ISABELLE_HOME/bin;
   502 
   503 * isatool logo -- create instances of the Isabelle logo (as EPS);
   504 
   505 * print mode 'emacs' reserved for Isamode;
   506 
   507 * support multiple print (ast) translations per constant name;
   508 
   509 * theorems involving oracles are now printed with a suffixed [!];
   510 
   511 
   512 *** HOL ***
   513 
   514 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   515 
   516 * HOL/inductive package reorganized and improved: now supports mutual
   517 definitions such as
   518 
   519   inductive EVEN ODD
   520     intrs
   521       null "0 : EVEN"
   522       oddI "n : EVEN ==> Suc n : ODD"
   523       evenI "n : ODD ==> Suc n : EVEN"
   524 
   525 new theorem list "elims" contains an elimination rule for each of the
   526 recursive sets; inductive definitions now handle disjunctive premises
   527 correctly (also ZF);
   528 
   529 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   530 "mutual_induct" no longer exists - the induction rule is always
   531 contained in "induct";
   532 
   533 
   534 * HOL/datatype package re-implemented and greatly improved: now
   535 supports mutually recursive datatypes such as
   536 
   537   datatype
   538     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   539             | SUM ('a aexp) ('a aexp)
   540             | DIFF ('a aexp) ('a aexp)
   541             | NUM 'a
   542   and
   543     'a bexp = LESS ('a aexp) ('a aexp)
   544             | AND ('a bexp) ('a bexp)
   545             | OR ('a bexp) ('a bexp)
   546 
   547 as well as indirectly recursive datatypes such as
   548 
   549   datatype
   550     ('a, 'b) term = Var 'a
   551                   | App 'b ((('a, 'b) term) list)
   552 
   553 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   554 induction on mutually / indirectly recursive datatypes.
   555 
   556 Primrec equations are now stored in theory and can be accessed via
   557 <function_name>.simps.
   558 
   559 INCOMPATIBILITIES:
   560 
   561   - Theories using datatypes must now have theory Datatype as an
   562     ancestor.
   563   - The specific <typename>.induct_tac no longer exists - use the
   564     generic induct_tac instead.
   565   - natE has been renamed to nat.exhaust - use exhaust_tac
   566     instead of res_inst_tac ... natE. Note that the variable
   567     names in nat.exhaust differ from the names in natE, this
   568     may cause some "fragile" proofs to fail.
   569   - The theorems split_<typename>_case and split_<typename>_case_asm
   570     have been renamed to <typename>.split and <typename>.split_asm.
   571   - Since default sorts of type variables are now handled correctly,
   572     some datatype definitions may have to be annotated with explicit
   573     sort constraints.
   574   - Primrec definitions no longer require function name and type
   575     of recursive argument.
   576 
   577 Consider using isatool fixdatatype to adapt your theories and proof
   578 scripts to the new package (backup your sources first!).
   579 
   580 
   581 * HOL/record package: considerably improved implementation; now
   582 includes concrete syntax for record types, terms, updates; theorems
   583 for surjective pairing and splitting !!-bound record variables; proof
   584 support is as follows:
   585 
   586   1) standard conversions (selectors or updates applied to record
   587 constructor terms) are part of the standard simpset;
   588 
   589   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   590 made part of standard simpset and claset via addIffs;
   591 
   592   3) a tactic for record field splitting (record_split_tac) is part of
   593 the standard claset (addSWrapper);
   594 
   595 To get a better idea about these rules you may retrieve them via
   596 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   597 the name of your record type.
   598 
   599 The split tactic 3) conceptually simplifies by the following rule:
   600 
   601   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   602 
   603 Thus any record variable that is bound by meta-all will automatically
   604 blow up into some record constructor term, consequently the
   605 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   606 solve record problems automatically.
   607 
   608 
   609 * reorganized the main HOL image: HOL/Integ and String loaded by
   610 default; theory Main includes everything;
   611 
   612 * automatic simplification of integer sums and comparisons, using cancellation;
   613 
   614 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   615 
   616 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   617 
   618 * many new identities for unions, intersections, set difference, etc.;
   619 
   620 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   621 called split_if, split_split, split_sum_case and split_nat_case (to go
   622 with add/delsplits);
   623 
   624 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   625 (?x::unit) = (); this is made part of the default simpset, which COULD
   626 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   627 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   628 unit_abs_eta_conv is added in order to counter the effect of
   629 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   630 %u.f();
   631 
   632 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   633 makes more sense);
   634 
   635 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   636   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   637   disjointness reasoning but breaking a few old proofs.
   638 
   639 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   640 to 'converse' from 'inverse' (for compatibility with ZF and some
   641 literature);
   642 
   643 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   644 the well-founded relation;
   645 
   646 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   647     Compl A.  The "Compl" syntax remains available as input syntax for this
   648     release ONLY.
   649 
   650 * HOL/Update: new theory of function updates:
   651     f(a:=b) == %x. if x=a then b else f x
   652 may also be iterated as in f(a:=b,c:=d,...);
   653 
   654 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   655 
   656 * HOL/List:
   657   - new function list_update written xs[i:=v] that updates the i-th
   658     list position. May also be iterated as in xs[i:=a,j:=b,...].
   659   - new function `upt' written [i..j(] which generates the list
   660     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   661     bound write [i..j], which is a shorthand for [i..j+1(].
   662   - new lexicographic orderings and corresponding wellfoundedness theorems.
   663 
   664 * HOL/Arith:
   665   - removed 'pred' (predecessor) function;
   666   - generalized some theorems about n-1;
   667   - many new laws about "div" and "mod";
   668   - new laws about greatest common divisors (see theory ex/Primes);
   669 
   670 * HOL/Relation: renamed the relational operator r^-1 "converse"
   671 instead of "inverse";
   672 
   673 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   674   of the multiset ordering;
   675 
   676 * directory HOL/Real: a construction of the reals using Dedekind cuts
   677   (not included by default);
   678 
   679 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   680 
   681 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   682   programs, i.e. different program variables may have different types.
   683 
   684 * calling (stac rew i) now fails if "rew" has no effect on the goal
   685   [previously, this check worked only if the rewrite rule was unconditional]
   686   Now rew can involve either definitions or equalities (either == or =).
   687 
   688 
   689 *** ZF ***
   690 
   691 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   692   only the theorems proved on ZF.ML;
   693 
   694 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   695   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   696   disjointness reasoning but breaking a few old proofs.
   697 
   698 * ZF/Update: new theory of function updates
   699     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   700   may also be iterated as in f(a:=b,c:=d,...);
   701 
   702 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   703 
   704 * calling (stac rew i) now fails if "rew" has no effect on the goal
   705   [previously, this check worked only if the rewrite rule was unconditional]
   706   Now rew can involve either definitions or equalities (either == or =).
   707 
   708 * case_tac provided for compatibility with HOL
   709     (like the old excluded_middle_tac, but with subgoals swapped)
   710 
   711 
   712 *** Internal programming interfaces ***
   713 
   714 * Pure: several new basic modules made available for general use, see
   715 also src/Pure/README;
   716 
   717 * improved the theory data mechanism to support encapsulation (data
   718 kind name replaced by private Object.kind, acting as authorization
   719 key); new type-safe user interface via functor TheoryDataFun; generic
   720 print_data function becomes basically useless;
   721 
   722 * removed global_names compatibility flag -- all theory declarations
   723 are qualified by default;
   724 
   725 * module Pure/Syntax now offers quote / antiquote translation
   726 functions (useful for Hoare logic etc. with implicit dependencies);
   727 see HOL/ex/Antiquote for an example use;
   728 
   729 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   730 cterm -> thm;
   731 
   732 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   733 subgoal;
   734 
   735 * Display.print_goals function moved to Locale.print_goals;
   736 
   737 * standard print function for goals supports current_goals_markers
   738 variable for marking begin of proof, end of proof, start of goal; the
   739 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   740 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   741 for example;
   742 
   743 
   744 
   745 New in Isabelle98 (January 1998)
   746 --------------------------------
   747 
   748 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   749 
   750 * changed lexical syntax of terms / types: dots made part of long
   751 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   752 
   753 * simpset (and claset) reference variable replaced by functions
   754 simpset / simpset_ref;
   755 
   756 * no longer supports theory aliases (via merge) and non-trivial
   757 implicit merge of thms' signatures;
   758 
   759 * most internal names of constants changed due to qualified names;
   760 
   761 * changed Pure/Sequence interface (see Pure/seq.ML);
   762 
   763 
   764 *** General Changes ***
   765 
   766 * hierachically structured name spaces (for consts, types, axms, thms
   767 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   768 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   769 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   770 long_names for fully qualified output names; NOTE: ML programs
   771 (special tactics, packages etc.) referring to internal names may have
   772 to be adapted to cope with fully qualified names; in case of severe
   773 backward campatibility problems try setting 'global_names' at compile
   774 time to have enrything declared within a flat name space; one may also
   775 fine tune name declarations in theories via the 'global' and 'local'
   776 section;
   777 
   778 * reimplemented the implicit simpset and claset using the new anytype
   779 data filed in signatures; references simpset:simpset ref etc. are
   780 replaced by functions simpset:unit->simpset and
   781 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   782 to patch your ML files accordingly;
   783 
   784 * HTML output now includes theory graph data for display with Java
   785 applet or isatool browser; data generated automatically via isatool
   786 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   787 
   788 * defs may now be conditional; improved rewrite_goals_tac to handle
   789 conditional equations;
   790 
   791 * defs now admits additional type arguments, using TYPE('a) syntax;
   792 
   793 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   794 creates a new theory node; implicit merge of thms' signatures is
   795 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   796 transfer:theory->thm->thm in (rare) cases;
   797 
   798 * improved handling of draft signatures / theories; draft thms (and
   799 ctyps, cterms) are automatically promoted to real ones;
   800 
   801 * slightly changed interfaces for oracles: admit many per theory, named
   802 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   803 
   804 * print_goals: optional output of const types (set show_consts and
   805 show_types);
   806 
   807 * improved output of warnings (###) and errors (***);
   808 
   809 * subgoal_tac displays a warning if the new subgoal has type variables;
   810 
   811 * removed old README and Makefiles;
   812 
   813 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   814 
   815 * removed obsolete init_pps and init_database;
   816 
   817 * deleted the obsolete tactical STATE, which was declared by
   818     fun STATE tacfun st = tacfun st st;
   819 
   820 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   821 (which abbreviates $HOME);
   822 
   823 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   824 use isatool fixseq to adapt your ML programs (this works for fully
   825 qualified references to the Sequence structure only!);
   826 
   827 * use_thy no longer requires writable current directory; it always
   828 reloads .ML *and* .thy file, if either one is out of date;
   829 
   830 
   831 *** Classical Reasoner ***
   832 
   833 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   834 tactics that use classical reasoning to simplify a subgoal without
   835 splitting it into several subgoals;
   836 
   837 * Safe_tac: like safe_tac but uses the default claset;
   838 
   839 
   840 *** Simplifier ***
   841 
   842 * added simplification meta rules:
   843     (asm_)(full_)simplify: simpset -> thm -> thm;
   844 
   845 * simplifier.ML no longer part of Pure -- has to be loaded by object
   846 logics (again);
   847 
   848 * added prems argument to simplification procedures;
   849 
   850 * HOL, FOL, ZF: added infix function `addsplits':
   851   instead of `<simpset> setloop (split_tac <thms>)'
   852   you can simply write `<simpset> addsplits <thms>'
   853 
   854 
   855 *** Syntax ***
   856 
   857 * TYPE('a) syntax for type reflection terms;
   858 
   859 * no longer handles consts with name "" -- declare as 'syntax' instead;
   860 
   861 * pretty printer: changed order of mixfix annotation preference (again!);
   862 
   863 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   864 
   865 
   866 *** HOL ***
   867 
   868 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   869   with `addloop' of the simplifier to faciliate case splitting in premises.
   870 
   871 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   872 
   873 * HOL/Auth: new protocol proofs including some for the Internet
   874   protocol TLS;
   875 
   876 * HOL/Map: new theory of `maps' a la VDM;
   877 
   878 * HOL/simplifier: simplification procedures nat_cancel_sums for
   879 cancelling out common nat summands from =, <, <= (in)equalities, or
   880 differences; simplification procedures nat_cancel_factor for
   881 cancelling common factor from =, <, <= (in)equalities over natural
   882 sums; nat_cancel contains both kinds of procedures, it is installed by
   883 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   884 
   885 * HOL/simplifier: terms of the form
   886   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   887   are rewritten to
   888   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   889   and those of the form
   890   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   891   are rewritten to
   892   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   893 
   894 * HOL/datatype
   895   Each datatype `t' now comes with a theorem `split_t_case' of the form
   896 
   897   P(t_case f1 ... fn x) =
   898      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   899         ...
   900        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   901      )
   902 
   903   and a theorem `split_t_case_asm' of the form
   904 
   905   P(t_case f1 ... fn x) =
   906     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   907         ...
   908        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   909      )
   910   which can be added to a simpset via `addsplits'. The existing theorems
   911   expand_list_case and expand_option_case have been renamed to
   912   split_list_case and split_option_case.
   913 
   914 * HOL/Arithmetic:
   915   - `pred n' is automatically converted to `n-1'.
   916     Users are strongly encouraged not to use `pred' any longer,
   917     because it will disappear altogether at some point.
   918   - Users are strongly encouraged to write "0 < n" rather than
   919     "n ~= 0". Theorems and proof tools have been modified towards this
   920     `standard'.
   921 
   922 * HOL/Lists:
   923   the function "set_of_list" has been renamed "set" (and its theorems too);
   924   the function "nth" now takes its arguments in the reverse order and
   925   has acquired the infix notation "!" as in "xs!n".
   926 
   927 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   928 
   929 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   930   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   931 
   932 * HOL/record: extensible records with schematic structural subtyping
   933 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   934 still lacks various theorems and concrete record syntax;
   935 
   936 
   937 *** HOLCF ***
   938 
   939 * removed "axioms" and "generated by" sections;
   940 
   941 * replaced "ops" section by extended "consts" section, which is capable of
   942   handling the continuous function space "->" directly;
   943 
   944 * domain package:
   945   . proves theorems immediately and stores them in the theory,
   946   . creates hierachical name space,
   947   . now uses normal mixfix annotations (instead of cinfix...),
   948   . minor changes to some names and values (for consistency),
   949   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   950   . separator between mutual domain defs: changed "," to "and",
   951   . improved handling of sort constraints;  now they have to
   952     appear on the left-hand side of the equations only;
   953 
   954 * fixed LAM <x,y,zs>.b syntax;
   955 
   956 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   957 adm (%x. P (t x)), where P is chainfinite and t continuous;
   958 
   959 
   960 *** FOL and ZF ***
   961 
   962 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   963   with `addloop' of the simplifier to faciliate case splitting in premises.
   964 
   965 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   966 in HOL, they strip ALL and --> from proved theorems;
   967 
   968 
   969 
   970 New in Isabelle94-8 (May 1997)
   971 ------------------------------
   972 
   973 *** General Changes ***
   974 
   975 * new utilities to build / run / maintain Isabelle etc. (in parts
   976 still somewhat experimental); old Makefiles etc. still functional;
   977 
   978 * new 'Isabelle System Manual';
   979 
   980 * INSTALL text, together with ./configure and ./build scripts;
   981 
   982 * reimplemented type inference for greater efficiency, better error
   983 messages and clean internal interface;
   984 
   985 * prlim command for dealing with lots of subgoals (an easier way of
   986 setting goals_limit);
   987 
   988 
   989 *** Syntax ***
   990 
   991 * supports alternative (named) syntax tables (parser and pretty
   992 printer); internal interface is provided by add_modesyntax(_i);
   993 
   994 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   995 be used in conjunction with the Isabelle symbol font; uses the
   996 "symbols" syntax table;
   997 
   998 * added token_translation interface (may translate name tokens in
   999 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1000 the current print_mode); IMPORTANT: user print translation functions
  1001 are responsible for marking newly introduced bounds
  1002 (Syntax.mark_boundT);
  1003 
  1004 * token translations for modes "xterm" and "xterm_color" that display
  1005 names in bold, underline etc. or colors (which requires a color
  1006 version of xterm);
  1007 
  1008 * infixes may now be declared with names independent of their syntax;
  1009 
  1010 * added typed_print_translation (like print_translation, but may
  1011 access type of constant);
  1012 
  1013 
  1014 *** Classical Reasoner ***
  1015 
  1016 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1017 some limitations.  Blast_tac...
  1018   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1019   + ignores elimination rules that don't have the correct format
  1020         (the conclusion MUST be a formula variable)
  1021   + ignores types, which can make HOL proofs fail
  1022   + rules must not require higher-order unification, e.g. apply_type in ZF
  1023     [message "Function Var's argument not a bound variable" relates to this]
  1024   + its proof strategy is more general but can actually be slower
  1025 
  1026 * substitution with equality assumptions no longer permutes other
  1027 assumptions;
  1028 
  1029 * minor changes in semantics of addafter (now called addaltern); renamed
  1030 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1031 (and access functions for it);
  1032 
  1033 * improved combination of classical reasoner and simplifier:
  1034   + functions for handling clasimpsets
  1035   + improvement of addss: now the simplifier is called _after_ the
  1036     safe steps.
  1037   + safe variant of addss called addSss: uses safe simplifications
  1038     _during_ the safe steps. It is more complete as it allows multiple
  1039     instantiations of unknowns (e.g. with slow_tac).
  1040 
  1041 *** Simplifier ***
  1042 
  1043 * added interface for simplification procedures (functions that
  1044 produce *proven* rewrite rules on the fly, depending on current
  1045 redex);
  1046 
  1047 * ordering on terms as parameter (used for ordered rewriting);
  1048 
  1049 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1050 
  1051 * the solver is now split into a safe and an unsafe part.
  1052 This should be invisible for the normal user, except that the
  1053 functions setsolver and addsolver have been renamed to setSolver and
  1054 addSolver; added safe_asm_full_simp_tac;
  1055 
  1056 
  1057 *** HOL ***
  1058 
  1059 * a generic induction tactic `induct_tac' which works for all datatypes and
  1060 also for type `nat';
  1061 
  1062 * a generic case distinction tactic `exhaust_tac' which works for all
  1063 datatypes and also for type `nat';
  1064 
  1065 * each datatype comes with a function `size';
  1066 
  1067 * patterns in case expressions allow tuple patterns as arguments to
  1068 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1069 
  1070 * primrec now also works with type nat;
  1071 
  1072 * recdef: a new declaration form, allows general recursive functions to be
  1073 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1074 
  1075 * the constant for negation has been renamed from "not" to "Not" to
  1076 harmonize with FOL, ZF, LK, etc.;
  1077 
  1078 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1079 infinite lists;
  1080 
  1081 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1082 
  1083 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1084 problems in commutative rings, using axiomatic type classes for + and *;
  1085 
  1086 * more examples in HOL/MiniML and HOL/Auth;
  1087 
  1088 * more default rewrite rules for quantifiers, union/intersection;
  1089 
  1090 * a new constant `arbitrary == @x.False';
  1091 
  1092 * HOLCF/IOA replaces old HOL/IOA;
  1093 
  1094 * HOLCF changes: derived all rules and arities
  1095   + axiomatic type classes instead of classes
  1096   + typedef instead of faking type definitions
  1097   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1098   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1099   + eliminated the types void, one, tr
  1100   + use unit lift and bool lift (with translations) instead of one and tr
  1101   + eliminated blift from Lift3.thy (use Def instead of blift)
  1102   all eliminated rules are derived as theorems --> no visible changes ;
  1103 
  1104 
  1105 *** ZF ***
  1106 
  1107 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1108 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1109 as ZF_cs addSIs [equalityI];
  1110 
  1111 
  1112 
  1113 New in Isabelle94-7 (November 96)
  1114 ---------------------------------
  1115 
  1116 * allowing negative levels (as offsets) in prlev and choplev;
  1117 
  1118 * super-linear speedup for large simplifications;
  1119 
  1120 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1121 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1122 FAIL); can suppress it using the command Delsimps (ex_simps @
  1123 all_simps); De Morgan laws are also now included, by default;
  1124 
  1125 * improved printing of ==>  :  ~:
  1126 
  1127 * new object-logic "Sequents" adds linear logic, while replacing LK
  1128 and Modal (thanks to Sara Kalvala);
  1129 
  1130 * HOL/Auth: correctness proofs for authentication protocols;
  1131 
  1132 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1133 examples on HOL/Auth);
  1134 
  1135 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1136 the rewriter and classical reasoner simultaneously;
  1137 
  1138 * function uresult no longer returns theorems in "standard" format;
  1139 regain previous version by: val uresult = standard o uresult;
  1140 
  1141 
  1142 
  1143 New in Isabelle94-6
  1144 -------------------
  1145 
  1146 * oracles -- these establish an interface between Isabelle and trusted
  1147 external reasoners, which may deliver results as theorems;
  1148 
  1149 * proof objects (in particular record all uses of oracles);
  1150 
  1151 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1152 
  1153 * "constdefs" section in theory files;
  1154 
  1155 * "primrec" section (HOL) no longer requires names;
  1156 
  1157 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1158 
  1159 
  1160 
  1161 New in Isabelle94-5
  1162 -------------------
  1163 
  1164 * reduced space requirements;
  1165 
  1166 * automatic HTML generation from theories;
  1167 
  1168 * theory files no longer require "..." (quotes) around most types;
  1169 
  1170 * new examples, including two proofs of the Church-Rosser theorem;
  1171 
  1172 * non-curried (1994) version of HOL is no longer distributed;
  1173 
  1174 
  1175 
  1176 New in Isabelle94-4
  1177 -------------------
  1178 
  1179 * greatly reduced space requirements;
  1180 
  1181 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1182 
  1183 * searchable theorem database (see the section "Retrieving theorems" on
  1184 page 8 of the Reference Manual);
  1185 
  1186 * new examples, including Grabczewski's monumental case study of the
  1187 Axiom of Choice;
  1188 
  1189 * The previous version of HOL renamed to Old_HOL;
  1190 
  1191 * The new version of HOL (previously called CHOL) uses a curried syntax
  1192 for functions.  Application looks like f a b instead of f(a,b);
  1193 
  1194 * Mutually recursive inductive definitions finally work in HOL;
  1195 
  1196 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1197 translates to the operator "split";
  1198 
  1199 
  1200 
  1201 New in Isabelle94-3
  1202 -------------------
  1203 
  1204 * new infix operator, addss, allowing the classical reasoner to
  1205 perform simplification at each step of its search.  Example:
  1206         fast_tac (cs addss ss)
  1207 
  1208 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1209 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1210 look like (a,b) instead of <a,b>;
  1211 
  1212 * PLEASE NOTE: CHOL will eventually replace HOL!
  1213 
  1214 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1215 It translates to the operator "split".  A new theory of integers is available;
  1216 
  1217 * In ZF, integer numerals now denote two's-complement binary integers.
  1218 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1219 
  1220 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1221 of the Axiom of Choice;
  1222 
  1223 
  1224 
  1225 New in Isabelle94-2
  1226 -------------------
  1227 
  1228 * Significantly faster resolution;
  1229 
  1230 * the different sections in a .thy file can now be mixed and repeated
  1231 freely;
  1232 
  1233 * Database of theorems for FOL, HOL and ZF.  New
  1234 commands including qed, qed_goal and bind_thm store theorems in the database.
  1235 
  1236 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1237 a given theory (thms_of), or find out what theory a theorem was proved in
  1238 (theory_of_thm);
  1239 
  1240 * Bugs fixed in the inductive definition and datatype packages;
  1241 
  1242 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1243 and HOL_dup_cs obsolete;
  1244 
  1245 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1246 have been removed;
  1247 
  1248 * Simpler definition of function space in ZF;
  1249 
  1250 * new results about cardinal and ordinal arithmetic in ZF;
  1251 
  1252 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1253 types;
  1254 
  1255 
  1256 $Id$