NEWS
author paulson
Thu Mar 09 16:07:01 2000 +0100 (2000-03-09)
changeset 8392 5bf82327aa36
parent 8358 a57d72b5d272
child 8412 65f9089f6f71
permissions -rw-r--r--
Factorization
     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 *** General ***
    57 
    58 * compression of ML heaps images may now be controlled via -c option
    59 of isabelle and isatool usedir;
    60 
    61 
    62 
    63 New in Isabelle99 (October 1999)
    64 --------------------------------
    65 
    66 *** Overview of INCOMPATIBILITIES (see below for more details) ***
    67 
    68 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
    69 are no longer simplified.  (This allows the simplifier to unfold recursive
    70 functional programs.)  To restore the old behaviour, declare
    71 
    72     Delcongs [if_weak_cong];
    73 
    74 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
    75 complement;
    76 
    77 * HOL: the predicate "inj" is now defined by translation to "inj_on";
    78 
    79 * HOL/datatype: mutual_induct_tac no longer exists --
    80   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
    81 
    82 * HOL/typedef: fixed type inference for representing set; type
    83 arguments now have to occur explicitly on the rhs as type constraints;
    84 
    85 * ZF: The con_defs part of an inductive definition may no longer refer
    86 to constants declared in the same theory;
    87 
    88 * HOL, ZF: the function mk_cases, generated by the inductive
    89 definition package, has lost an argument.  To simplify its result, it
    90 uses the default simpset instead of a supplied list of theorems.
    91 
    92 * HOL/List: the constructors of type list are now Nil and Cons;
    93 
    94 * Simplifier: the type of the infix ML functions
    95 	setSSolver addSSolver setSolver addSolver
    96 is now  simpset * solver -> simpset  where `solver' is a new abstract type
    97 for packaging solvers. A solver is created via
    98 	mk_solver: string -> (thm list -> int -> tactic) -> solver
    99 where the string argument is only a comment.
   100 
   101 
   102 *** Proof tools ***
   103 
   104 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   105 decision procedure for linear arithmetic. Currently it is used for
   106 types `nat', `int', and `real' in HOL (see below); it can, should and
   107 will be instantiated for other types and logics as well.
   108 
   109 * The simplifier now accepts rewrite rules with flexible heads, eg
   110      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   111   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   112   matching.
   113 
   114 
   115 *** General ***
   116 
   117 * New Isabelle/Isar subsystem provides an alternative to traditional
   118 tactical theorem proving; together with the ProofGeneral/isar user
   119 interface it offers an interactive environment for developing human
   120 readable proof documents (Isar == Intelligible semi-automated
   121 reasoning); for further information see isatool doc isar-ref,
   122 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   123 
   124 * improved presentation of theories: better HTML markup (including
   125 colors), graph views in several sizes; isatool usedir now provides a
   126 proper interface for user theories (via -P option); actual document
   127 preparation based on (PDF)LaTeX is available as well (for new-style
   128 theories only); see isatool doc system for more information;
   129 
   130 * native support for Proof General, both for classic Isabelle and
   131 Isabelle/Isar;
   132 
   133 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   134 using the graph browser tool;
   135 
   136 * Isabelle manuals now also available as PDF;
   137 
   138 * theory loader rewritten from scratch (may not be fully
   139 bug-compatible); old loadpath variable has been replaced by show_path,
   140 add_path, del_path, reset_path functions; new operations such as
   141 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   142 isatool doc ref);
   143 
   144 * improved isatool install: option -k creates KDE application icon,
   145 option -p DIR installs standalone binaries;
   146 
   147 * added ML_PLATFORM setting (useful for cross-platform installations);
   148 more robust handling of platform specific ML images for SML/NJ;
   149 
   150 * the settings environment is now statically scoped, i.e. it is never
   151 created again in sub-processes invoked from isabelle, isatool, or
   152 Isabelle;
   153 
   154 * path element specification '~~' refers to '$ISABELLE_HOME';
   155 
   156 * in locales, the "assumes" and "defines" parts may be omitted if
   157 empty;
   158 
   159 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   160 long arrows);
   161 
   162 * new print_mode "HTML";
   163 
   164 * new flag show_tags controls display of tags of theorems (which are
   165 basically just comments that may be attached by some tools);
   166 
   167 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   168 mode and goal output format:
   169 
   170 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   171 244c244
   172 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   173 ---
   174 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   175 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   176 181c181
   177 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   178 ---
   179 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   180 
   181 * function bind_thms stores lists of theorems (cf. bind_thm);
   182 
   183 * new shorthand tactics ftac, eatac, datac, fatac;
   184 
   185 * qed (and friends) now accept "" as result name; in that case the
   186 theorem is not stored, but proper checks and presentation of the
   187 result still apply;
   188 
   189 * theorem database now also indexes constants "Trueprop", "all",
   190 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   191 
   192 
   193 *** HOL ***
   194 
   195 ** HOL arithmetic **
   196 
   197 * There are now decision procedures for linear arithmetic over nat and
   198 int:
   199 
   200 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   201 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   202 are treated as atomic; subformulae not involving type `nat' or `int'
   203 are ignored; quantified subformulae are ignored unless they are
   204 positive universal or negative existential. The tactic has to be
   205 invoked by hand and can be a little bit slow. In particular, the
   206 running time is exponential in the number of occurrences of `min' and
   207 `max', and `-' on `nat'.
   208 
   209 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   210 (negated) (in)equalities among the premises and the conclusion into
   211 account (i.e. no compound formulae) and does not know about `min' and
   212 `max', and `-' on `nat'. It is fast and is used automatically by the
   213 simplifier.
   214 
   215 NB: At the moment, these decision procedures do not cope with mixed
   216 nat/int formulae where the two parts interact, such as `m < n ==>
   217 int(m) < int(n)'.
   218 
   219 * HOL/Numeral provides a generic theory of numerals (encoded
   220 efficiently as bit strings); setup for types nat/int/real is in place;
   221 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   222 int, existing theories and proof scripts may require a few additional
   223 type constraints;
   224 
   225 * integer division and remainder can now be performed on constant
   226 arguments;
   227 
   228 * many properties of integer multiplication, division and remainder
   229 are now available;
   230 
   231 * An interface to the Stanford Validity Checker (SVC) is available through the
   232 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   233 are proved automatically.  SVC must be installed separately, and its results
   234 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   235 invocation of the underlying oracle).  For SVC see
   236   http://verify.stanford.edu/SVC
   237 
   238 * IsaMakefile: the HOL-Real target now builds an actual image;
   239 
   240 
   241 ** HOL misc **
   242 
   243 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   244 (in Isabelle/Isar) -- by Gertrud Bauer;
   245 
   246 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   247 analysis for assembly languages with subtypes;
   248 
   249 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   250 -- avoids syntactic ambiguities and treats state, transition, and
   251 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   252 changed syntax and (many) tactics;
   253 
   254 * HOL/inductive: Now also handles more general introduction rules such
   255   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   256   theorems are now maintained within the theory (maintained via the
   257   "mono" attribute);
   258 
   259 * HOL/datatype: Now also handles arbitrarily branching datatypes
   260   (using function types) such as
   261 
   262   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   263 
   264 * HOL/record: record_simproc (part of the default simpset) takes care
   265 of selectors applied to updated records; record_split_tac is no longer
   266 part of the default claset; update_defs may now be removed from the
   267 simpset in many cases; COMPATIBILITY: old behavior achieved by
   268 
   269   claset_ref () := claset() addSWrapper record_split_wrapper;
   270   Delsimprocs [record_simproc]
   271 
   272 * HOL/typedef: fixed type inference for representing set; type
   273 arguments now have to occur explicitly on the rhs as type constraints;
   274 
   275 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   276 names rather than an ML expression;
   277 
   278 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   279 supplied later.  Program schemes can be defined, such as
   280     "While B C s = (if B s then While B C (C s) else s)"
   281 where the well-founded relation can be chosen after B and C have been given.
   282 
   283 * HOL/List: the constructors of type list are now Nil and Cons;
   284 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   285 course, ML tools referring to List.list.op # etc. have to be adapted;
   286 
   287 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   288 disabled by default; run isabelle with option -m HOL to get back to
   289 the original Gordon/HOL-style output;
   290 
   291 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   292 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   293 
   294 * HOL basic syntax simplified (more orthogonal): all variants of
   295 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   296 Eps operator is provided as well: "SOME x. P[x]";
   297 
   298 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   299 
   300 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   301 thus available for user theories;
   302 
   303 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   304 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   305 time;
   306 
   307 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   308 several times and then mp;
   309 
   310 
   311 *** LK ***
   312 
   313 * the notation <<...>> is now available as a notation for sequences of
   314 formulas;
   315 
   316 * the simplifier is now installed
   317 
   318 * the axiom system has been generalized (thanks to Soren Heilmann) 
   319 
   320 * the classical reasoner now has a default rule database
   321 
   322 
   323 *** ZF ***
   324 
   325 * new primrec section allows primitive recursive functions to be given
   326 directly (as in HOL) over datatypes and the natural numbers;
   327 
   328 * new tactics induct_tac and exhaust_tac for induction (or case
   329 analysis) over datatypes and the natural numbers;
   330 
   331 * the datatype declaration of type T now defines the recursor T_rec;
   332 
   333 * simplification automatically does freeness reasoning for datatype
   334 constructors;
   335 
   336 * automatic type-inference, with AddTCs command to insert new
   337 type-checking rules;
   338 
   339 * datatype introduction rules are now added as Safe Introduction rules
   340 to the claset;
   341 
   342 * the syntax "if P then x else y" is now available in addition to
   343 if(P,x,y);
   344 
   345 
   346 *** Internal programming interfaces ***
   347 
   348 * tuned simplifier trace output; new flag debug_simp;
   349 
   350 * structures Vartab / Termtab (instances of TableFun) offer efficient
   351 tables indexed by indexname_ord / term_ord (compatible with aconv);
   352 
   353 * AxClass.axclass_tac lost the theory argument;
   354 
   355 * tuned current_goals_markers semantics: begin / end goal avoids
   356 printing empty lines;
   357 
   358 * removed prs and prs_fn hook, which was broken because it did not
   359 include \n in its semantics, forcing writeln to add one
   360 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   361 string -> unit if you really want to output text without newline;
   362 
   363 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   364 plain output, interface builders may have to enable 'isabelle_font'
   365 mode to get Isabelle font glyphs as before;
   366 
   367 * refined token_translation interface; INCOMPATIBILITY: output length
   368 now of type real instead of int;
   369 
   370 * theory loader actions may be traced via new ThyInfo.add_hook
   371 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   372 your own database of information attached to *whole* theories -- as
   373 opposed to intra-theory data slots offered via TheoryDataFun;
   374 
   375 * proper handling of dangling sort hypotheses (at last!);
   376 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   377 extra sort hypotheses that can be witnessed from the type signature;
   378 the force_strip_shyps flag is gone, any remaining shyps are simply
   379 left in the theorem (with a warning issued by strip_shyps_warning);
   380 
   381 
   382 
   383 New in Isabelle98-1 (October 1998)
   384 ----------------------------------
   385 
   386 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   387 
   388 * several changes of automated proof tools;
   389 
   390 * HOL: major changes to the inductive and datatype packages, including
   391 some minor incompatibilities of theory syntax;
   392 
   393 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   394 called `inj_on';
   395 
   396 * HOL: removed duplicate thms in Arith:
   397   less_imp_add_less  should be replaced by  trans_less_add1
   398   le_imp_add_le      should be replaced by  trans_le_add1
   399 
   400 * HOL: unary minus is now overloaded (new type constraints may be
   401 required);
   402 
   403 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   404 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   405 now taken as an integer constant.
   406 
   407 * Pure: ML function 'theory_of' renamed to 'theory';
   408 
   409 
   410 *** Proof tools ***
   411 
   412 * Simplifier:
   413   1. Asm_full_simp_tac is now more aggressive.
   414      1. It will sometimes reorient premises if that increases their power to
   415         simplify.
   416      2. It does no longer proceed strictly from left to right but may also
   417         rotate premises to achieve further simplification.
   418      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   419      old Asm_full_simp_tac in that it does not rotate premises.
   420   2. The simplifier now knows a little bit about nat-arithmetic.
   421 
   422 * Classical reasoner: wrapper mechanism for the classical reasoner now
   423 allows for selected deletion of wrappers, by introduction of names for
   424 wrapper functionals.  This implies that addbefore, addSbefore,
   425 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   426 and that adding two tactics with the same name overwrites the first
   427 one (emitting a warning).
   428   type wrapper = (int -> tactic) -> (int -> tactic)
   429   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   430   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   431   delWrapper, delSWrapper: claset *  string            -> claset
   432   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   433 
   434 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   435 semantics; addbefore now affects only the unsafe part of step_tac
   436 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   437 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   438 by Force_tac;
   439 
   440 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   441 compWrapper; added safe wrapper (and access functions for it);
   442 
   443 * HOL/split_all_tac is now much faster and fails if there is nothing
   444 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   445 and the names of the automatically generated variables have changed.
   446 split_all_tac has moved within claset() from unsafe wrappers to safe
   447 wrappers, which means that !!-bound variables are split much more
   448 aggressively, and safe_tac and clarify_tac now split such variables.
   449 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   450 Note: the same holds for record_split_tac, which does the job of
   451 split_all_tac for record fields.
   452 
   453 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   454 permanently to the default simpset using Addsplits just like
   455 Addsimps. They can be removed via Delsplits just like
   456 Delsimps. Lower-case versions are also available.
   457 
   458 * HOL/Simplifier: The rule split_if is now part of the default
   459 simpset. This means that the simplifier will eliminate all occurrences
   460 of if-then-else in the conclusion of a goal. To prevent this, you can
   461 either remove split_if completely from the default simpset by
   462 `Delsplits [split_if]' or remove it in a specific call of the
   463 simplifier using `... delsplits [split_if]'.  You can also add/delete
   464 other case splitting rules to/from the default simpset: every datatype
   465 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   466 t is the name of the datatype).
   467 
   468 * Classical reasoner / Simplifier combination: new force_tac (and
   469 derivatives Force_tac, force) combines rewriting and classical
   470 reasoning (and whatever other tools) similarly to auto_tac, but is
   471 aimed to solve the given subgoal completely.
   472 
   473 
   474 *** General ***
   475 
   476 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   477 and `goalw': the theory is no longer needed as an explicit argument -
   478 the current theory context is used; assumptions are no longer returned
   479 at the ML-level unless one of them starts with ==> or !!; it is
   480 recommended to convert to these new commands using isatool fixgoal
   481 (backup your sources first!);
   482 
   483 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   484 the current theory context, and 'theory' to lookup stored theories;
   485 
   486 * new theory section 'locale' for declaring constants, assumptions and
   487 definitions that have local scope;
   488 
   489 * new theory section 'nonterminals' for purely syntactic types;
   490 
   491 * new theory section 'setup' for generic ML setup functions
   492 (e.g. package initialization);
   493 
   494 * the distribution now includes Isabelle icons: see
   495 lib/logo/isabelle-{small,tiny}.xpm;
   496 
   497 * isatool install - install binaries with absolute references to
   498 ISABELLE_HOME/bin;
   499 
   500 * isatool logo -- create instances of the Isabelle logo (as EPS);
   501 
   502 * print mode 'emacs' reserved for Isamode;
   503 
   504 * support multiple print (ast) translations per constant name;
   505 
   506 * theorems involving oracles are now printed with a suffixed [!];
   507 
   508 
   509 *** HOL ***
   510 
   511 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   512 
   513 * HOL/inductive package reorganized and improved: now supports mutual
   514 definitions such as
   515 
   516   inductive EVEN ODD
   517     intrs
   518       null "0 : EVEN"
   519       oddI "n : EVEN ==> Suc n : ODD"
   520       evenI "n : ODD ==> Suc n : EVEN"
   521 
   522 new theorem list "elims" contains an elimination rule for each of the
   523 recursive sets; inductive definitions now handle disjunctive premises
   524 correctly (also ZF);
   525 
   526 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   527 "mutual_induct" no longer exists - the induction rule is always
   528 contained in "induct";
   529 
   530 
   531 * HOL/datatype package re-implemented and greatly improved: now
   532 supports mutually recursive datatypes such as
   533 
   534   datatype
   535     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   536             | SUM ('a aexp) ('a aexp)
   537             | DIFF ('a aexp) ('a aexp)
   538             | NUM 'a
   539   and
   540     'a bexp = LESS ('a aexp) ('a aexp)
   541             | AND ('a bexp) ('a bexp)
   542             | OR ('a bexp) ('a bexp)
   543 
   544 as well as indirectly recursive datatypes such as
   545 
   546   datatype
   547     ('a, 'b) term = Var 'a
   548                   | App 'b ((('a, 'b) term) list)
   549 
   550 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   551 induction on mutually / indirectly recursive datatypes.
   552 
   553 Primrec equations are now stored in theory and can be accessed via
   554 <function_name>.simps.
   555 
   556 INCOMPATIBILITIES:
   557 
   558   - Theories using datatypes must now have theory Datatype as an
   559     ancestor.
   560   - The specific <typename>.induct_tac no longer exists - use the
   561     generic induct_tac instead.
   562   - natE has been renamed to nat.exhaust - use exhaust_tac
   563     instead of res_inst_tac ... natE. Note that the variable
   564     names in nat.exhaust differ from the names in natE, this
   565     may cause some "fragile" proofs to fail.
   566   - The theorems split_<typename>_case and split_<typename>_case_asm
   567     have been renamed to <typename>.split and <typename>.split_asm.
   568   - Since default sorts of type variables are now handled correctly,
   569     some datatype definitions may have to be annotated with explicit
   570     sort constraints.
   571   - Primrec definitions no longer require function name and type
   572     of recursive argument.
   573 
   574 Consider using isatool fixdatatype to adapt your theories and proof
   575 scripts to the new package (backup your sources first!).
   576 
   577 
   578 * HOL/record package: considerably improved implementation; now
   579 includes concrete syntax for record types, terms, updates; theorems
   580 for surjective pairing and splitting !!-bound record variables; proof
   581 support is as follows:
   582 
   583   1) standard conversions (selectors or updates applied to record
   584 constructor terms) are part of the standard simpset;
   585 
   586   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   587 made part of standard simpset and claset via addIffs;
   588 
   589   3) a tactic for record field splitting (record_split_tac) is part of
   590 the standard claset (addSWrapper);
   591 
   592 To get a better idea about these rules you may retrieve them via
   593 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   594 the name of your record type.
   595 
   596 The split tactic 3) conceptually simplifies by the following rule:
   597 
   598   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   599 
   600 Thus any record variable that is bound by meta-all will automatically
   601 blow up into some record constructor term, consequently the
   602 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   603 solve record problems automatically.
   604 
   605 
   606 * reorganized the main HOL image: HOL/Integ and String loaded by
   607 default; theory Main includes everything;
   608 
   609 * automatic simplification of integer sums and comparisons, using cancellation;
   610 
   611 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   612 
   613 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   614 
   615 * many new identities for unions, intersections, set difference, etc.;
   616 
   617 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   618 called split_if, split_split, split_sum_case and split_nat_case (to go
   619 with add/delsplits);
   620 
   621 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   622 (?x::unit) = (); this is made part of the default simpset, which COULD
   623 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   624 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   625 unit_abs_eta_conv is added in order to counter the effect of
   626 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   627 %u.f();
   628 
   629 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   630 makes more sense);
   631 
   632 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   633   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   634   disjointness reasoning but breaking a few old proofs.
   635 
   636 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   637 to 'converse' from 'inverse' (for compatibility with ZF and some
   638 literature);
   639 
   640 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   641 the well-founded relation;
   642 
   643 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   644     Compl A.  The "Compl" syntax remains available as input syntax for this
   645     release ONLY.
   646 
   647 * HOL/Update: new theory of function updates:
   648     f(a:=b) == %x. if x=a then b else f x
   649 may also be iterated as in f(a:=b,c:=d,...);
   650 
   651 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   652 
   653 * HOL/List:
   654   - new function list_update written xs[i:=v] that updates the i-th
   655     list position. May also be iterated as in xs[i:=a,j:=b,...].
   656   - new function `upt' written [i..j(] which generates the list
   657     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   658     bound write [i..j], which is a shorthand for [i..j+1(].
   659   - new lexicographic orderings and corresponding wellfoundedness theorems.
   660 
   661 * HOL/Arith:
   662   - removed 'pred' (predecessor) function;
   663   - generalized some theorems about n-1;
   664   - many new laws about "div" and "mod";
   665   - new laws about greatest common divisors (see theory ex/Primes);
   666 
   667 * HOL/Relation: renamed the relational operator r^-1 "converse"
   668 instead of "inverse";
   669 
   670 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   671   of the multiset ordering;
   672 
   673 * directory HOL/Real: a construction of the reals using Dedekind cuts
   674   (not included by default);
   675 
   676 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   677 
   678 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   679   programs, i.e. different program variables may have different types.
   680 
   681 * calling (stac rew i) now fails if "rew" has no effect on the goal
   682   [previously, this check worked only if the rewrite rule was unconditional]
   683   Now rew can involve either definitions or equalities (either == or =).
   684 
   685 
   686 *** ZF ***
   687 
   688 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   689   only the theorems proved on ZF.ML;
   690 
   691 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   692   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   693   disjointness reasoning but breaking a few old proofs.
   694 
   695 * ZF/Update: new theory of function updates
   696     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   697   may also be iterated as in f(a:=b,c:=d,...);
   698 
   699 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   700 
   701 * calling (stac rew i) now fails if "rew" has no effect on the goal
   702   [previously, this check worked only if the rewrite rule was unconditional]
   703   Now rew can involve either definitions or equalities (either == or =).
   704 
   705 * case_tac provided for compatibility with HOL
   706     (like the old excluded_middle_tac, but with subgoals swapped)
   707 
   708 
   709 *** Internal programming interfaces ***
   710 
   711 * Pure: several new basic modules made available for general use, see
   712 also src/Pure/README;
   713 
   714 * improved the theory data mechanism to support encapsulation (data
   715 kind name replaced by private Object.kind, acting as authorization
   716 key); new type-safe user interface via functor TheoryDataFun; generic
   717 print_data function becomes basically useless;
   718 
   719 * removed global_names compatibility flag -- all theory declarations
   720 are qualified by default;
   721 
   722 * module Pure/Syntax now offers quote / antiquote translation
   723 functions (useful for Hoare logic etc. with implicit dependencies);
   724 see HOL/ex/Antiquote for an example use;
   725 
   726 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   727 cterm -> thm;
   728 
   729 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   730 subgoal;
   731 
   732 * Display.print_goals function moved to Locale.print_goals;
   733 
   734 * standard print function for goals supports current_goals_markers
   735 variable for marking begin of proof, end of proof, start of goal; the
   736 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   737 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   738 for example;
   739 
   740 
   741 
   742 New in Isabelle98 (January 1998)
   743 --------------------------------
   744 
   745 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   746 
   747 * changed lexical syntax of terms / types: dots made part of long
   748 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   749 
   750 * simpset (and claset) reference variable replaced by functions
   751 simpset / simpset_ref;
   752 
   753 * no longer supports theory aliases (via merge) and non-trivial
   754 implicit merge of thms' signatures;
   755 
   756 * most internal names of constants changed due to qualified names;
   757 
   758 * changed Pure/Sequence interface (see Pure/seq.ML);
   759 
   760 
   761 *** General Changes ***
   762 
   763 * hierachically structured name spaces (for consts, types, axms, thms
   764 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   765 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   766 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   767 long_names for fully qualified output names; NOTE: ML programs
   768 (special tactics, packages etc.) referring to internal names may have
   769 to be adapted to cope with fully qualified names; in case of severe
   770 backward campatibility problems try setting 'global_names' at compile
   771 time to have enrything declared within a flat name space; one may also
   772 fine tune name declarations in theories via the 'global' and 'local'
   773 section;
   774 
   775 * reimplemented the implicit simpset and claset using the new anytype
   776 data filed in signatures; references simpset:simpset ref etc. are
   777 replaced by functions simpset:unit->simpset and
   778 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   779 to patch your ML files accordingly;
   780 
   781 * HTML output now includes theory graph data for display with Java
   782 applet or isatool browser; data generated automatically via isatool
   783 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   784 
   785 * defs may now be conditional; improved rewrite_goals_tac to handle
   786 conditional equations;
   787 
   788 * defs now admits additional type arguments, using TYPE('a) syntax;
   789 
   790 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   791 creates a new theory node; implicit merge of thms' signatures is
   792 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   793 transfer:theory->thm->thm in (rare) cases;
   794 
   795 * improved handling of draft signatures / theories; draft thms (and
   796 ctyps, cterms) are automatically promoted to real ones;
   797 
   798 * slightly changed interfaces for oracles: admit many per theory, named
   799 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   800 
   801 * print_goals: optional output of const types (set show_consts and
   802 show_types);
   803 
   804 * improved output of warnings (###) and errors (***);
   805 
   806 * subgoal_tac displays a warning if the new subgoal has type variables;
   807 
   808 * removed old README and Makefiles;
   809 
   810 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   811 
   812 * removed obsolete init_pps and init_database;
   813 
   814 * deleted the obsolete tactical STATE, which was declared by
   815     fun STATE tacfun st = tacfun st st;
   816 
   817 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   818 (which abbreviates $HOME);
   819 
   820 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   821 use isatool fixseq to adapt your ML programs (this works for fully
   822 qualified references to the Sequence structure only!);
   823 
   824 * use_thy no longer requires writable current directory; it always
   825 reloads .ML *and* .thy file, if either one is out of date;
   826 
   827 
   828 *** Classical Reasoner ***
   829 
   830 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   831 tactics that use classical reasoning to simplify a subgoal without
   832 splitting it into several subgoals;
   833 
   834 * Safe_tac: like safe_tac but uses the default claset;
   835 
   836 
   837 *** Simplifier ***
   838 
   839 * added simplification meta rules:
   840     (asm_)(full_)simplify: simpset -> thm -> thm;
   841 
   842 * simplifier.ML no longer part of Pure -- has to be loaded by object
   843 logics (again);
   844 
   845 * added prems argument to simplification procedures;
   846 
   847 * HOL, FOL, ZF: added infix function `addsplits':
   848   instead of `<simpset> setloop (split_tac <thms>)'
   849   you can simply write `<simpset> addsplits <thms>'
   850 
   851 
   852 *** Syntax ***
   853 
   854 * TYPE('a) syntax for type reflection terms;
   855 
   856 * no longer handles consts with name "" -- declare as 'syntax' instead;
   857 
   858 * pretty printer: changed order of mixfix annotation preference (again!);
   859 
   860 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   861 
   862 
   863 *** HOL ***
   864 
   865 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   866   with `addloop' of the simplifier to faciliate case splitting in premises.
   867 
   868 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   869 
   870 * HOL/Auth: new protocol proofs including some for the Internet
   871   protocol TLS;
   872 
   873 * HOL/Map: new theory of `maps' a la VDM;
   874 
   875 * HOL/simplifier: simplification procedures nat_cancel_sums for
   876 cancelling out common nat summands from =, <, <= (in)equalities, or
   877 differences; simplification procedures nat_cancel_factor for
   878 cancelling common factor from =, <, <= (in)equalities over natural
   879 sums; nat_cancel contains both kinds of procedures, it is installed by
   880 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   881 
   882 * HOL/simplifier: terms of the form
   883   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   884   are rewritten to
   885   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   886   and those of the form
   887   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   888   are rewritten to
   889   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   890 
   891 * HOL/datatype
   892   Each datatype `t' now comes with a theorem `split_t_case' of the form
   893 
   894   P(t_case f1 ... fn x) =
   895      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   896         ...
   897        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   898      )
   899 
   900   and a theorem `split_t_case_asm' of the form
   901 
   902   P(t_case f1 ... fn x) =
   903     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   904         ...
   905        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   906      )
   907   which can be added to a simpset via `addsplits'. The existing theorems
   908   expand_list_case and expand_option_case have been renamed to
   909   split_list_case and split_option_case.
   910 
   911 * HOL/Arithmetic:
   912   - `pred n' is automatically converted to `n-1'.
   913     Users are strongly encouraged not to use `pred' any longer,
   914     because it will disappear altogether at some point.
   915   - Users are strongly encouraged to write "0 < n" rather than
   916     "n ~= 0". Theorems and proof tools have been modified towards this
   917     `standard'.
   918 
   919 * HOL/Lists:
   920   the function "set_of_list" has been renamed "set" (and its theorems too);
   921   the function "nth" now takes its arguments in the reverse order and
   922   has acquired the infix notation "!" as in "xs!n".
   923 
   924 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   925 
   926 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   927   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   928 
   929 * HOL/record: extensible records with schematic structural subtyping
   930 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   931 still lacks various theorems and concrete record syntax;
   932 
   933 
   934 *** HOLCF ***
   935 
   936 * removed "axioms" and "generated by" sections;
   937 
   938 * replaced "ops" section by extended "consts" section, which is capable of
   939   handling the continuous function space "->" directly;
   940 
   941 * domain package:
   942   . proves theorems immediately and stores them in the theory,
   943   . creates hierachical name space,
   944   . now uses normal mixfix annotations (instead of cinfix...),
   945   . minor changes to some names and values (for consistency),
   946   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   947   . separator between mutual domain defs: changed "," to "and",
   948   . improved handling of sort constraints;  now they have to
   949     appear on the left-hand side of the equations only;
   950 
   951 * fixed LAM <x,y,zs>.b syntax;
   952 
   953 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   954 adm (%x. P (t x)), where P is chainfinite and t continuous;
   955 
   956 
   957 *** FOL and ZF ***
   958 
   959 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
   960   with `addloop' of the simplifier to faciliate case splitting in premises.
   961 
   962 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
   963 in HOL, they strip ALL and --> from proved theorems;
   964 
   965 
   966 
   967 New in Isabelle94-8 (May 1997)
   968 ------------------------------
   969 
   970 *** General Changes ***
   971 
   972 * new utilities to build / run / maintain Isabelle etc. (in parts
   973 still somewhat experimental); old Makefiles etc. still functional;
   974 
   975 * new 'Isabelle System Manual';
   976 
   977 * INSTALL text, together with ./configure and ./build scripts;
   978 
   979 * reimplemented type inference for greater efficiency, better error
   980 messages and clean internal interface;
   981 
   982 * prlim command for dealing with lots of subgoals (an easier way of
   983 setting goals_limit);
   984 
   985 
   986 *** Syntax ***
   987 
   988 * supports alternative (named) syntax tables (parser and pretty
   989 printer); internal interface is provided by add_modesyntax(_i);
   990 
   991 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
   992 be used in conjunction with the Isabelle symbol font; uses the
   993 "symbols" syntax table;
   994 
   995 * added token_translation interface (may translate name tokens in
   996 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
   997 the current print_mode); IMPORTANT: user print translation functions
   998 are responsible for marking newly introduced bounds
   999 (Syntax.mark_boundT);
  1000 
  1001 * token translations for modes "xterm" and "xterm_color" that display
  1002 names in bold, underline etc. or colors (which requires a color
  1003 version of xterm);
  1004 
  1005 * infixes may now be declared with names independent of their syntax;
  1006 
  1007 * added typed_print_translation (like print_translation, but may
  1008 access type of constant);
  1009 
  1010 
  1011 *** Classical Reasoner ***
  1012 
  1013 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1014 some limitations.  Blast_tac...
  1015   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1016   + ignores elimination rules that don't have the correct format
  1017         (the conclusion MUST be a formula variable)
  1018   + ignores types, which can make HOL proofs fail
  1019   + rules must not require higher-order unification, e.g. apply_type in ZF
  1020     [message "Function Var's argument not a bound variable" relates to this]
  1021   + its proof strategy is more general but can actually be slower
  1022 
  1023 * substitution with equality assumptions no longer permutes other
  1024 assumptions;
  1025 
  1026 * minor changes in semantics of addafter (now called addaltern); renamed
  1027 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1028 (and access functions for it);
  1029 
  1030 * improved combination of classical reasoner and simplifier:
  1031   + functions for handling clasimpsets
  1032   + improvement of addss: now the simplifier is called _after_ the
  1033     safe steps.
  1034   + safe variant of addss called addSss: uses safe simplifications
  1035     _during_ the safe steps. It is more complete as it allows multiple
  1036     instantiations of unknowns (e.g. with slow_tac).
  1037 
  1038 *** Simplifier ***
  1039 
  1040 * added interface for simplification procedures (functions that
  1041 produce *proven* rewrite rules on the fly, depending on current
  1042 redex);
  1043 
  1044 * ordering on terms as parameter (used for ordered rewriting);
  1045 
  1046 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1047 
  1048 * the solver is now split into a safe and an unsafe part.
  1049 This should be invisible for the normal user, except that the
  1050 functions setsolver and addsolver have been renamed to setSolver and
  1051 addSolver; added safe_asm_full_simp_tac;
  1052 
  1053 
  1054 *** HOL ***
  1055 
  1056 * a generic induction tactic `induct_tac' which works for all datatypes and
  1057 also for type `nat';
  1058 
  1059 * a generic case distinction tactic `exhaust_tac' which works for all
  1060 datatypes and also for type `nat';
  1061 
  1062 * each datatype comes with a function `size';
  1063 
  1064 * patterns in case expressions allow tuple patterns as arguments to
  1065 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1066 
  1067 * primrec now also works with type nat;
  1068 
  1069 * recdef: a new declaration form, allows general recursive functions to be
  1070 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1071 
  1072 * the constant for negation has been renamed from "not" to "Not" to
  1073 harmonize with FOL, ZF, LK, etc.;
  1074 
  1075 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1076 infinite lists;
  1077 
  1078 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1079 
  1080 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1081 problems in commutative rings, using axiomatic type classes for + and *;
  1082 
  1083 * more examples in HOL/MiniML and HOL/Auth;
  1084 
  1085 * more default rewrite rules for quantifiers, union/intersection;
  1086 
  1087 * a new constant `arbitrary == @x.False';
  1088 
  1089 * HOLCF/IOA replaces old HOL/IOA;
  1090 
  1091 * HOLCF changes: derived all rules and arities
  1092   + axiomatic type classes instead of classes
  1093   + typedef instead of faking type definitions
  1094   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1095   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1096   + eliminated the types void, one, tr
  1097   + use unit lift and bool lift (with translations) instead of one and tr
  1098   + eliminated blift from Lift3.thy (use Def instead of blift)
  1099   all eliminated rules are derived as theorems --> no visible changes ;
  1100 
  1101 
  1102 *** ZF ***
  1103 
  1104 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1105 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1106 as ZF_cs addSIs [equalityI];
  1107 
  1108 
  1109 
  1110 New in Isabelle94-7 (November 96)
  1111 ---------------------------------
  1112 
  1113 * allowing negative levels (as offsets) in prlev and choplev;
  1114 
  1115 * super-linear speedup for large simplifications;
  1116 
  1117 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1118 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1119 FAIL); can suppress it using the command Delsimps (ex_simps @
  1120 all_simps); De Morgan laws are also now included, by default;
  1121 
  1122 * improved printing of ==>  :  ~:
  1123 
  1124 * new object-logic "Sequents" adds linear logic, while replacing LK
  1125 and Modal (thanks to Sara Kalvala);
  1126 
  1127 * HOL/Auth: correctness proofs for authentication protocols;
  1128 
  1129 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1130 examples on HOL/Auth);
  1131 
  1132 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1133 the rewriter and classical reasoner simultaneously;
  1134 
  1135 * function uresult no longer returns theorems in "standard" format;
  1136 regain previous version by: val uresult = standard o uresult;
  1137 
  1138 
  1139 
  1140 New in Isabelle94-6
  1141 -------------------
  1142 
  1143 * oracles -- these establish an interface between Isabelle and trusted
  1144 external reasoners, which may deliver results as theorems;
  1145 
  1146 * proof objects (in particular record all uses of oracles);
  1147 
  1148 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1149 
  1150 * "constdefs" section in theory files;
  1151 
  1152 * "primrec" section (HOL) no longer requires names;
  1153 
  1154 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1155 
  1156 
  1157 
  1158 New in Isabelle94-5
  1159 -------------------
  1160 
  1161 * reduced space requirements;
  1162 
  1163 * automatic HTML generation from theories;
  1164 
  1165 * theory files no longer require "..." (quotes) around most types;
  1166 
  1167 * new examples, including two proofs of the Church-Rosser theorem;
  1168 
  1169 * non-curried (1994) version of HOL is no longer distributed;
  1170 
  1171 
  1172 
  1173 New in Isabelle94-4
  1174 -------------------
  1175 
  1176 * greatly reduced space requirements;
  1177 
  1178 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1179 
  1180 * searchable theorem database (see the section "Retrieving theorems" on
  1181 page 8 of the Reference Manual);
  1182 
  1183 * new examples, including Grabczewski's monumental case study of the
  1184 Axiom of Choice;
  1185 
  1186 * The previous version of HOL renamed to Old_HOL;
  1187 
  1188 * The new version of HOL (previously called CHOL) uses a curried syntax
  1189 for functions.  Application looks like f a b instead of f(a,b);
  1190 
  1191 * Mutually recursive inductive definitions finally work in HOL;
  1192 
  1193 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1194 translates to the operator "split";
  1195 
  1196 
  1197 
  1198 New in Isabelle94-3
  1199 -------------------
  1200 
  1201 * new infix operator, addss, allowing the classical reasoner to
  1202 perform simplification at each step of its search.  Example:
  1203         fast_tac (cs addss ss)
  1204 
  1205 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1206 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1207 look like (a,b) instead of <a,b>;
  1208 
  1209 * PLEASE NOTE: CHOL will eventually replace HOL!
  1210 
  1211 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1212 It translates to the operator "split".  A new theory of integers is available;
  1213 
  1214 * In ZF, integer numerals now denote two's-complement binary integers.
  1215 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1216 
  1217 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1218 of the Axiom of Choice;
  1219 
  1220 
  1221 
  1222 New in Isabelle94-2
  1223 -------------------
  1224 
  1225 * Significantly faster resolution;
  1226 
  1227 * the different sections in a .thy file can now be mixed and repeated
  1228 freely;
  1229 
  1230 * Database of theorems for FOL, HOL and ZF.  New
  1231 commands including qed, qed_goal and bind_thm store theorems in the database.
  1232 
  1233 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1234 a given theory (thms_of), or find out what theory a theorem was proved in
  1235 (theory_of_thm);
  1236 
  1237 * Bugs fixed in the inductive definition and datatype packages;
  1238 
  1239 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1240 and HOL_dup_cs obsolete;
  1241 
  1242 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1243 have been removed;
  1244 
  1245 * Simpler definition of function space in ZF;
  1246 
  1247 * new results about cardinal and ordinal arithmetic in ZF;
  1248 
  1249 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1250 types;
  1251 
  1252 
  1253 $Id$