NEWS
author wenzelm
Fri Mar 24 17:29:51 2000 +0100 (2000-03-24)
changeset 8570 63d4f3ea2e70
parent 8566 30261b1917b5
child 8603 805910de7be0
permissions -rw-r--r--
HOL/ex/Multiquote;
     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    12 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    13 
    14 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    15 
    16 
    17 *** Document preparation ***
    18 
    19 * isatool mkdir provides easy setup of Isabelle session directories,
    20 including proper document sources;
    21 
    22 * generated LaTeX sources are now deleted after successful run
    23 (isatool document -c); may retain a copy somewhere else via -D option
    24 of isatool usedir;
    25 
    26 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    27 style files, achieving self-contained LaTeX sources;
    28 
    29 * old-style theories now produce (crude) LaTeX output as well;
    30 
    31 
    32 *** Isar ***
    33 
    34 * Pure now provides its own version of intro/elim/dest attributes;
    35 useful for building new logics, but beware of confusion with the
    36 Provers/classical ones;
    37 
    38 * Pure: new 'obtain' language element supports generalized elimination
    39 proofs;
    40 
    41 * Pure: scalable support for case-analysis type proofs: new 'case'
    42 language element refers to local contexts symbolically, as produced by
    43 certain proof methods; internally, case names are attached to theorems
    44 as "tags";
    45 
    46 * Provers: splitter support (via 'split' attribute and 'simp' method
    47 modifier); 'simp' method: 'only:' modifier removes loopers as well
    48 (including splits);
    49 
    50 * HOL: new proof method 'cases' and improved version of 'induct' now
    51 support named cases; major packages (inductive, datatype, primrec,
    52 recdef) support case names and properly name parameters;
    53 
    54 * HOL: removed 'case_split' thm binding, should use 'cases' proof
    55 method anyway;
    56 
    57 * names of theorems etc. may be natural numbers as well;
    58 
    59 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
    60 
    61 * 'pr' command: optional goals_limit argument;
    62 
    63 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
    64 additional print modes to be specified; e.g. "pr(latex)" will print
    65 proof state according to the Isabelle LaTeX style;
    66 
    67 * improved support for emulating tactic scripts, including proof
    68 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
    69 'induct_tac' (for HOL datatypes);
    70 
    71 
    72 
    73 *** HOL ***
    74 
    75 * HOL/Algebra: new theory of rings and univariate polynomials, by
    76 Clemens Ballarin;
    77 
    78 * HOL/record: fixed select-update simplification procedure to handle
    79 extended records as well; admit "r" as field name;
    80 
    81 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
    82 Arithmetic, by Thomas M Rasmussen;
    83 
    84 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
    85 basically a generalized version of de-Bruijn representation; very
    86 useful in avoiding lifting all operations;
    87 
    88 * new version of "case_tac" subsumes both boolean case split and
    89 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
    90 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
    91 
    92 
    93 *** General ***
    94 
    95 * compression of ML heaps images may now be controlled via -c option
    96 of isabelle and isatool usedir (currently only observed by Poly/ML);
    97 
    98 * ML: new combinators |>> and |>>> for incremental transformations
    99 with secondary results (e.g. certain theory extensions):
   100 
   101 
   102 
   103 New in Isabelle99 (October 1999)
   104 --------------------------------
   105 
   106 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   107 
   108 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   109 are no longer simplified.  (This allows the simplifier to unfold recursive
   110 functional programs.)  To restore the old behaviour, declare
   111 
   112     Delcongs [if_weak_cong];
   113 
   114 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   115 complement;
   116 
   117 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   118 
   119 * HOL/datatype: mutual_induct_tac no longer exists --
   120   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   121 
   122 * HOL/typedef: fixed type inference for representing set; type
   123 arguments now have to occur explicitly on the rhs as type constraints;
   124 
   125 * ZF: The con_defs part of an inductive definition may no longer refer
   126 to constants declared in the same theory;
   127 
   128 * HOL, ZF: the function mk_cases, generated by the inductive
   129 definition package, has lost an argument.  To simplify its result, it
   130 uses the default simpset instead of a supplied list of theorems.
   131 
   132 * HOL/List: the constructors of type list are now Nil and Cons;
   133 
   134 * Simplifier: the type of the infix ML functions
   135 	setSSolver addSSolver setSolver addSolver
   136 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   137 for packaging solvers. A solver is created via
   138 	mk_solver: string -> (thm list -> int -> tactic) -> solver
   139 where the string argument is only a comment.
   140 
   141 
   142 *** Proof tools ***
   143 
   144 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   145 decision procedure for linear arithmetic. Currently it is used for
   146 types `nat', `int', and `real' in HOL (see below); it can, should and
   147 will be instantiated for other types and logics as well.
   148 
   149 * The simplifier now accepts rewrite rules with flexible heads, eg
   150      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   151   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   152   matching.
   153 
   154 
   155 *** General ***
   156 
   157 * New Isabelle/Isar subsystem provides an alternative to traditional
   158 tactical theorem proving; together with the ProofGeneral/isar user
   159 interface it offers an interactive environment for developing human
   160 readable proof documents (Isar == Intelligible semi-automated
   161 reasoning); for further information see isatool doc isar-ref,
   162 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   163 
   164 * improved presentation of theories: better HTML markup (including
   165 colors), graph views in several sizes; isatool usedir now provides a
   166 proper interface for user theories (via -P option); actual document
   167 preparation based on (PDF)LaTeX is available as well (for new-style
   168 theories only); see isatool doc system for more information;
   169 
   170 * native support for Proof General, both for classic Isabelle and
   171 Isabelle/Isar;
   172 
   173 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   174 using the graph browser tool;
   175 
   176 * Isabelle manuals now also available as PDF;
   177 
   178 * theory loader rewritten from scratch (may not be fully
   179 bug-compatible); old loadpath variable has been replaced by show_path,
   180 add_path, del_path, reset_path functions; new operations such as
   181 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   182 isatool doc ref);
   183 
   184 * improved isatool install: option -k creates KDE application icon,
   185 option -p DIR installs standalone binaries;
   186 
   187 * added ML_PLATFORM setting (useful for cross-platform installations);
   188 more robust handling of platform specific ML images for SML/NJ;
   189 
   190 * the settings environment is now statically scoped, i.e. it is never
   191 created again in sub-processes invoked from isabelle, isatool, or
   192 Isabelle;
   193 
   194 * path element specification '~~' refers to '$ISABELLE_HOME';
   195 
   196 * in locales, the "assumes" and "defines" parts may be omitted if
   197 empty;
   198 
   199 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   200 long arrows);
   201 
   202 * new print_mode "HTML";
   203 
   204 * new flag show_tags controls display of tags of theorems (which are
   205 basically just comments that may be attached by some tools);
   206 
   207 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   208 mode and goal output format:
   209 
   210 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   211 244c244
   212 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   213 ---
   214 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   215 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   216 181c181
   217 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   218 ---
   219 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   220 
   221 * function bind_thms stores lists of theorems (cf. bind_thm);
   222 
   223 * new shorthand tactics ftac, eatac, datac, fatac;
   224 
   225 * qed (and friends) now accept "" as result name; in that case the
   226 theorem is not stored, but proper checks and presentation of the
   227 result still apply;
   228 
   229 * theorem database now also indexes constants "Trueprop", "all",
   230 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   231 
   232 
   233 *** HOL ***
   234 
   235 ** HOL arithmetic **
   236 
   237 * There are now decision procedures for linear arithmetic over nat and
   238 int:
   239 
   240 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   241 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   242 are treated as atomic; subformulae not involving type `nat' or `int'
   243 are ignored; quantified subformulae are ignored unless they are
   244 positive universal or negative existential. The tactic has to be
   245 invoked by hand and can be a little bit slow. In particular, the
   246 running time is exponential in the number of occurrences of `min' and
   247 `max', and `-' on `nat'.
   248 
   249 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   250 (negated) (in)equalities among the premises and the conclusion into
   251 account (i.e. no compound formulae) and does not know about `min' and
   252 `max', and `-' on `nat'. It is fast and is used automatically by the
   253 simplifier.
   254 
   255 NB: At the moment, these decision procedures do not cope with mixed
   256 nat/int formulae where the two parts interact, such as `m < n ==>
   257 int(m) < int(n)'.
   258 
   259 * HOL/Numeral provides a generic theory of numerals (encoded
   260 efficiently as bit strings); setup for types nat/int/real is in place;
   261 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   262 int, existing theories and proof scripts may require a few additional
   263 type constraints;
   264 
   265 * integer division and remainder can now be performed on constant
   266 arguments;
   267 
   268 * many properties of integer multiplication, division and remainder
   269 are now available;
   270 
   271 * An interface to the Stanford Validity Checker (SVC) is available through the
   272 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   273 are proved automatically.  SVC must be installed separately, and its results
   274 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   275 invocation of the underlying oracle).  For SVC see
   276   http://verify.stanford.edu/SVC
   277 
   278 * IsaMakefile: the HOL-Real target now builds an actual image;
   279 
   280 
   281 ** HOL misc **
   282 
   283 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   284 (in Isabelle/Isar) -- by Gertrud Bauer;
   285 
   286 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   287 analysis for assembly languages with subtypes;
   288 
   289 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   290 -- avoids syntactic ambiguities and treats state, transition, and
   291 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   292 changed syntax and (many) tactics;
   293 
   294 * HOL/inductive: Now also handles more general introduction rules such
   295   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   296   theorems are now maintained within the theory (maintained via the
   297   "mono" attribute);
   298 
   299 * HOL/datatype: Now also handles arbitrarily branching datatypes
   300   (using function types) such as
   301 
   302   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   303 
   304 * HOL/record: record_simproc (part of the default simpset) takes care
   305 of selectors applied to updated records; record_split_tac is no longer
   306 part of the default claset; update_defs may now be removed from the
   307 simpset in many cases; COMPATIBILITY: old behavior achieved by
   308 
   309   claset_ref () := claset() addSWrapper record_split_wrapper;
   310   Delsimprocs [record_simproc]
   311 
   312 * HOL/typedef: fixed type inference for representing set; type
   313 arguments now have to occur explicitly on the rhs as type constraints;
   314 
   315 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   316 names rather than an ML expression;
   317 
   318 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   319 supplied later.  Program schemes can be defined, such as
   320     "While B C s = (if B s then While B C (C s) else s)"
   321 where the well-founded relation can be chosen after B and C have been given.
   322 
   323 * HOL/List: the constructors of type list are now Nil and Cons;
   324 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   325 course, ML tools referring to List.list.op # etc. have to be adapted;
   326 
   327 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   328 disabled by default; run isabelle with option -m HOL to get back to
   329 the original Gordon/HOL-style output;
   330 
   331 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   332 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   333 
   334 * HOL basic syntax simplified (more orthogonal): all variants of
   335 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   336 Eps operator is provided as well: "SOME x. P[x]";
   337 
   338 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   339 
   340 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   341 thus available for user theories;
   342 
   343 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   344 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   345 time;
   346 
   347 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   348 several times and then mp;
   349 
   350 
   351 *** LK ***
   352 
   353 * the notation <<...>> is now available as a notation for sequences of
   354 formulas;
   355 
   356 * the simplifier is now installed
   357 
   358 * the axiom system has been generalized (thanks to Soren Heilmann) 
   359 
   360 * the classical reasoner now has a default rule database
   361 
   362 
   363 *** ZF ***
   364 
   365 * new primrec section allows primitive recursive functions to be given
   366 directly (as in HOL) over datatypes and the natural numbers;
   367 
   368 * new tactics induct_tac and exhaust_tac for induction (or case
   369 analysis) over datatypes and the natural numbers;
   370 
   371 * the datatype declaration of type T now defines the recursor T_rec;
   372 
   373 * simplification automatically does freeness reasoning for datatype
   374 constructors;
   375 
   376 * automatic type-inference, with AddTCs command to insert new
   377 type-checking rules;
   378 
   379 * datatype introduction rules are now added as Safe Introduction rules
   380 to the claset;
   381 
   382 * the syntax "if P then x else y" is now available in addition to
   383 if(P,x,y);
   384 
   385 
   386 *** Internal programming interfaces ***
   387 
   388 * tuned simplifier trace output; new flag debug_simp;
   389 
   390 * structures Vartab / Termtab (instances of TableFun) offer efficient
   391 tables indexed by indexname_ord / term_ord (compatible with aconv);
   392 
   393 * AxClass.axclass_tac lost the theory argument;
   394 
   395 * tuned current_goals_markers semantics: begin / end goal avoids
   396 printing empty lines;
   397 
   398 * removed prs and prs_fn hook, which was broken because it did not
   399 include \n in its semantics, forcing writeln to add one
   400 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   401 string -> unit if you really want to output text without newline;
   402 
   403 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   404 plain output, interface builders may have to enable 'isabelle_font'
   405 mode to get Isabelle font glyphs as before;
   406 
   407 * refined token_translation interface; INCOMPATIBILITY: output length
   408 now of type real instead of int;
   409 
   410 * theory loader actions may be traced via new ThyInfo.add_hook
   411 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   412 your own database of information attached to *whole* theories -- as
   413 opposed to intra-theory data slots offered via TheoryDataFun;
   414 
   415 * proper handling of dangling sort hypotheses (at last!);
   416 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   417 extra sort hypotheses that can be witnessed from the type signature;
   418 the force_strip_shyps flag is gone, any remaining shyps are simply
   419 left in the theorem (with a warning issued by strip_shyps_warning);
   420 
   421 
   422 
   423 New in Isabelle98-1 (October 1998)
   424 ----------------------------------
   425 
   426 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   427 
   428 * several changes of automated proof tools;
   429 
   430 * HOL: major changes to the inductive and datatype packages, including
   431 some minor incompatibilities of theory syntax;
   432 
   433 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   434 called `inj_on';
   435 
   436 * HOL: removed duplicate thms in Arith:
   437   less_imp_add_less  should be replaced by  trans_less_add1
   438   le_imp_add_le      should be replaced by  trans_le_add1
   439 
   440 * HOL: unary minus is now overloaded (new type constraints may be
   441 required);
   442 
   443 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   444 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   445 now taken as an integer constant.
   446 
   447 * Pure: ML function 'theory_of' renamed to 'theory';
   448 
   449 
   450 *** Proof tools ***
   451 
   452 * Simplifier:
   453   1. Asm_full_simp_tac is now more aggressive.
   454      1. It will sometimes reorient premises if that increases their power to
   455         simplify.
   456      2. It does no longer proceed strictly from left to right but may also
   457         rotate premises to achieve further simplification.
   458      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   459      old Asm_full_simp_tac in that it does not rotate premises.
   460   2. The simplifier now knows a little bit about nat-arithmetic.
   461 
   462 * Classical reasoner: wrapper mechanism for the classical reasoner now
   463 allows for selected deletion of wrappers, by introduction of names for
   464 wrapper functionals.  This implies that addbefore, addSbefore,
   465 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   466 and that adding two tactics with the same name overwrites the first
   467 one (emitting a warning).
   468   type wrapper = (int -> tactic) -> (int -> tactic)
   469   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   470   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   471   delWrapper, delSWrapper: claset *  string            -> claset
   472   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   473 
   474 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   475 semantics; addbefore now affects only the unsafe part of step_tac
   476 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   477 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   478 by Force_tac;
   479 
   480 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   481 compWrapper; added safe wrapper (and access functions for it);
   482 
   483 * HOL/split_all_tac is now much faster and fails if there is nothing
   484 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   485 and the names of the automatically generated variables have changed.
   486 split_all_tac has moved within claset() from unsafe wrappers to safe
   487 wrappers, which means that !!-bound variables are split much more
   488 aggressively, and safe_tac and clarify_tac now split such variables.
   489 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   490 Note: the same holds for record_split_tac, which does the job of
   491 split_all_tac for record fields.
   492 
   493 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   494 permanently to the default simpset using Addsplits just like
   495 Addsimps. They can be removed via Delsplits just like
   496 Delsimps. Lower-case versions are also available.
   497 
   498 * HOL/Simplifier: The rule split_if is now part of the default
   499 simpset. This means that the simplifier will eliminate all occurrences
   500 of if-then-else in the conclusion of a goal. To prevent this, you can
   501 either remove split_if completely from the default simpset by
   502 `Delsplits [split_if]' or remove it in a specific call of the
   503 simplifier using `... delsplits [split_if]'.  You can also add/delete
   504 other case splitting rules to/from the default simpset: every datatype
   505 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   506 t is the name of the datatype).
   507 
   508 * Classical reasoner / Simplifier combination: new force_tac (and
   509 derivatives Force_tac, force) combines rewriting and classical
   510 reasoning (and whatever other tools) similarly to auto_tac, but is
   511 aimed to solve the given subgoal completely.
   512 
   513 
   514 *** General ***
   515 
   516 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   517 and `goalw': the theory is no longer needed as an explicit argument -
   518 the current theory context is used; assumptions are no longer returned
   519 at the ML-level unless one of them starts with ==> or !!; it is
   520 recommended to convert to these new commands using isatool fixgoal
   521 (backup your sources first!);
   522 
   523 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   524 the current theory context, and 'theory' to lookup stored theories;
   525 
   526 * new theory section 'locale' for declaring constants, assumptions and
   527 definitions that have local scope;
   528 
   529 * new theory section 'nonterminals' for purely syntactic types;
   530 
   531 * new theory section 'setup' for generic ML setup functions
   532 (e.g. package initialization);
   533 
   534 * the distribution now includes Isabelle icons: see
   535 lib/logo/isabelle-{small,tiny}.xpm;
   536 
   537 * isatool install - install binaries with absolute references to
   538 ISABELLE_HOME/bin;
   539 
   540 * isatool logo -- create instances of the Isabelle logo (as EPS);
   541 
   542 * print mode 'emacs' reserved for Isamode;
   543 
   544 * support multiple print (ast) translations per constant name;
   545 
   546 * theorems involving oracles are now printed with a suffixed [!];
   547 
   548 
   549 *** HOL ***
   550 
   551 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   552 
   553 * HOL/inductive package reorganized and improved: now supports mutual
   554 definitions such as
   555 
   556   inductive EVEN ODD
   557     intrs
   558       null "0 : EVEN"
   559       oddI "n : EVEN ==> Suc n : ODD"
   560       evenI "n : ODD ==> Suc n : EVEN"
   561 
   562 new theorem list "elims" contains an elimination rule for each of the
   563 recursive sets; inductive definitions now handle disjunctive premises
   564 correctly (also ZF);
   565 
   566 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   567 "mutual_induct" no longer exists - the induction rule is always
   568 contained in "induct";
   569 
   570 
   571 * HOL/datatype package re-implemented and greatly improved: now
   572 supports mutually recursive datatypes such as
   573 
   574   datatype
   575     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   576             | SUM ('a aexp) ('a aexp)
   577             | DIFF ('a aexp) ('a aexp)
   578             | NUM 'a
   579   and
   580     'a bexp = LESS ('a aexp) ('a aexp)
   581             | AND ('a bexp) ('a bexp)
   582             | OR ('a bexp) ('a bexp)
   583 
   584 as well as indirectly recursive datatypes such as
   585 
   586   datatype
   587     ('a, 'b) term = Var 'a
   588                   | App 'b ((('a, 'b) term) list)
   589 
   590 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   591 induction on mutually / indirectly recursive datatypes.
   592 
   593 Primrec equations are now stored in theory and can be accessed via
   594 <function_name>.simps.
   595 
   596 INCOMPATIBILITIES:
   597 
   598   - Theories using datatypes must now have theory Datatype as an
   599     ancestor.
   600   - The specific <typename>.induct_tac no longer exists - use the
   601     generic induct_tac instead.
   602   - natE has been renamed to nat.exhaust - use exhaust_tac
   603     instead of res_inst_tac ... natE. Note that the variable
   604     names in nat.exhaust differ from the names in natE, this
   605     may cause some "fragile" proofs to fail.
   606   - The theorems split_<typename>_case and split_<typename>_case_asm
   607     have been renamed to <typename>.split and <typename>.split_asm.
   608   - Since default sorts of type variables are now handled correctly,
   609     some datatype definitions may have to be annotated with explicit
   610     sort constraints.
   611   - Primrec definitions no longer require function name and type
   612     of recursive argument.
   613 
   614 Consider using isatool fixdatatype to adapt your theories and proof
   615 scripts to the new package (backup your sources first!).
   616 
   617 
   618 * HOL/record package: considerably improved implementation; now
   619 includes concrete syntax for record types, terms, updates; theorems
   620 for surjective pairing and splitting !!-bound record variables; proof
   621 support is as follows:
   622 
   623   1) standard conversions (selectors or updates applied to record
   624 constructor terms) are part of the standard simpset;
   625 
   626   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   627 made part of standard simpset and claset via addIffs;
   628 
   629   3) a tactic for record field splitting (record_split_tac) is part of
   630 the standard claset (addSWrapper);
   631 
   632 To get a better idea about these rules you may retrieve them via
   633 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   634 the name of your record type.
   635 
   636 The split tactic 3) conceptually simplifies by the following rule:
   637 
   638   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   639 
   640 Thus any record variable that is bound by meta-all will automatically
   641 blow up into some record constructor term, consequently the
   642 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   643 solve record problems automatically.
   644 
   645 
   646 * reorganized the main HOL image: HOL/Integ and String loaded by
   647 default; theory Main includes everything;
   648 
   649 * automatic simplification of integer sums and comparisons, using cancellation;
   650 
   651 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   652 
   653 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   654 
   655 * many new identities for unions, intersections, set difference, etc.;
   656 
   657 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   658 called split_if, split_split, split_sum_case and split_nat_case (to go
   659 with add/delsplits);
   660 
   661 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   662 (?x::unit) = (); this is made part of the default simpset, which COULD
   663 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   664 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   665 unit_abs_eta_conv is added in order to counter the effect of
   666 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   667 %u.f();
   668 
   669 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   670 makes more sense);
   671 
   672 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   673   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   674   disjointness reasoning but breaking a few old proofs.
   675 
   676 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   677 to 'converse' from 'inverse' (for compatibility with ZF and some
   678 literature);
   679 
   680 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   681 the well-founded relation;
   682 
   683 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   684     Compl A.  The "Compl" syntax remains available as input syntax for this
   685     release ONLY.
   686 
   687 * HOL/Update: new theory of function updates:
   688     f(a:=b) == %x. if x=a then b else f x
   689 may also be iterated as in f(a:=b,c:=d,...);
   690 
   691 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   692 
   693 * HOL/List:
   694   - new function list_update written xs[i:=v] that updates the i-th
   695     list position. May also be iterated as in xs[i:=a,j:=b,...].
   696   - new function `upt' written [i..j(] which generates the list
   697     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   698     bound write [i..j], which is a shorthand for [i..j+1(].
   699   - new lexicographic orderings and corresponding wellfoundedness theorems.
   700 
   701 * HOL/Arith:
   702   - removed 'pred' (predecessor) function;
   703   - generalized some theorems about n-1;
   704   - many new laws about "div" and "mod";
   705   - new laws about greatest common divisors (see theory ex/Primes);
   706 
   707 * HOL/Relation: renamed the relational operator r^-1 "converse"
   708 instead of "inverse";
   709 
   710 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   711   of the multiset ordering;
   712 
   713 * directory HOL/Real: a construction of the reals using Dedekind cuts
   714   (not included by default);
   715 
   716 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   717 
   718 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   719   programs, i.e. different program variables may have different types.
   720 
   721 * calling (stac rew i) now fails if "rew" has no effect on the goal
   722   [previously, this check worked only if the rewrite rule was unconditional]
   723   Now rew can involve either definitions or equalities (either == or =).
   724 
   725 
   726 *** ZF ***
   727 
   728 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   729   only the theorems proved on ZF.ML;
   730 
   731 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   732   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   733   disjointness reasoning but breaking a few old proofs.
   734 
   735 * ZF/Update: new theory of function updates
   736     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   737   may also be iterated as in f(a:=b,c:=d,...);
   738 
   739 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   740 
   741 * calling (stac rew i) now fails if "rew" has no effect on the goal
   742   [previously, this check worked only if the rewrite rule was unconditional]
   743   Now rew can involve either definitions or equalities (either == or =).
   744 
   745 * case_tac provided for compatibility with HOL
   746     (like the old excluded_middle_tac, but with subgoals swapped)
   747 
   748 
   749 *** Internal programming interfaces ***
   750 
   751 * Pure: several new basic modules made available for general use, see
   752 also src/Pure/README;
   753 
   754 * improved the theory data mechanism to support encapsulation (data
   755 kind name replaced by private Object.kind, acting as authorization
   756 key); new type-safe user interface via functor TheoryDataFun; generic
   757 print_data function becomes basically useless;
   758 
   759 * removed global_names compatibility flag -- all theory declarations
   760 are qualified by default;
   761 
   762 * module Pure/Syntax now offers quote / antiquote translation
   763 functions (useful for Hoare logic etc. with implicit dependencies);
   764 see HOL/ex/Antiquote for an example use;
   765 
   766 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   767 cterm -> thm;
   768 
   769 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   770 subgoal;
   771 
   772 * Display.print_goals function moved to Locale.print_goals;
   773 
   774 * standard print function for goals supports current_goals_markers
   775 variable for marking begin of proof, end of proof, start of goal; the
   776 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   777 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   778 for example;
   779 
   780 
   781 
   782 New in Isabelle98 (January 1998)
   783 --------------------------------
   784 
   785 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   786 
   787 * changed lexical syntax of terms / types: dots made part of long
   788 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   789 
   790 * simpset (and claset) reference variable replaced by functions
   791 simpset / simpset_ref;
   792 
   793 * no longer supports theory aliases (via merge) and non-trivial
   794 implicit merge of thms' signatures;
   795 
   796 * most internal names of constants changed due to qualified names;
   797 
   798 * changed Pure/Sequence interface (see Pure/seq.ML);
   799 
   800 
   801 *** General Changes ***
   802 
   803 * hierachically structured name spaces (for consts, types, axms, thms
   804 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   805 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   806 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   807 long_names for fully qualified output names; NOTE: ML programs
   808 (special tactics, packages etc.) referring to internal names may have
   809 to be adapted to cope with fully qualified names; in case of severe
   810 backward campatibility problems try setting 'global_names' at compile
   811 time to have enrything declared within a flat name space; one may also
   812 fine tune name declarations in theories via the 'global' and 'local'
   813 section;
   814 
   815 * reimplemented the implicit simpset and claset using the new anytype
   816 data filed in signatures; references simpset:simpset ref etc. are
   817 replaced by functions simpset:unit->simpset and
   818 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   819 to patch your ML files accordingly;
   820 
   821 * HTML output now includes theory graph data for display with Java
   822 applet or isatool browser; data generated automatically via isatool
   823 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   824 
   825 * defs may now be conditional; improved rewrite_goals_tac to handle
   826 conditional equations;
   827 
   828 * defs now admits additional type arguments, using TYPE('a) syntax;
   829 
   830 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   831 creates a new theory node; implicit merge of thms' signatures is
   832 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   833 transfer:theory->thm->thm in (rare) cases;
   834 
   835 * improved handling of draft signatures / theories; draft thms (and
   836 ctyps, cterms) are automatically promoted to real ones;
   837 
   838 * slightly changed interfaces for oracles: admit many per theory, named
   839 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   840 
   841 * print_goals: optional output of const types (set show_consts and
   842 show_types);
   843 
   844 * improved output of warnings (###) and errors (***);
   845 
   846 * subgoal_tac displays a warning if the new subgoal has type variables;
   847 
   848 * removed old README and Makefiles;
   849 
   850 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   851 
   852 * removed obsolete init_pps and init_database;
   853 
   854 * deleted the obsolete tactical STATE, which was declared by
   855     fun STATE tacfun st = tacfun st st;
   856 
   857 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   858 (which abbreviates $HOME);
   859 
   860 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   861 use isatool fixseq to adapt your ML programs (this works for fully
   862 qualified references to the Sequence structure only!);
   863 
   864 * use_thy no longer requires writable current directory; it always
   865 reloads .ML *and* .thy file, if either one is out of date;
   866 
   867 
   868 *** Classical Reasoner ***
   869 
   870 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   871 tactics that use classical reasoning to simplify a subgoal without
   872 splitting it into several subgoals;
   873 
   874 * Safe_tac: like safe_tac but uses the default claset;
   875 
   876 
   877 *** Simplifier ***
   878 
   879 * added simplification meta rules:
   880     (asm_)(full_)simplify: simpset -> thm -> thm;
   881 
   882 * simplifier.ML no longer part of Pure -- has to be loaded by object
   883 logics (again);
   884 
   885 * added prems argument to simplification procedures;
   886 
   887 * HOL, FOL, ZF: added infix function `addsplits':
   888   instead of `<simpset> setloop (split_tac <thms>)'
   889   you can simply write `<simpset> addsplits <thms>'
   890 
   891 
   892 *** Syntax ***
   893 
   894 * TYPE('a) syntax for type reflection terms;
   895 
   896 * no longer handles consts with name "" -- declare as 'syntax' instead;
   897 
   898 * pretty printer: changed order of mixfix annotation preference (again!);
   899 
   900 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   901 
   902 
   903 *** HOL ***
   904 
   905 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   906   with `addloop' of the simplifier to faciliate case splitting in premises.
   907 
   908 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   909 
   910 * HOL/Auth: new protocol proofs including some for the Internet
   911   protocol TLS;
   912 
   913 * HOL/Map: new theory of `maps' a la VDM;
   914 
   915 * HOL/simplifier: simplification procedures nat_cancel_sums for
   916 cancelling out common nat summands from =, <, <= (in)equalities, or
   917 differences; simplification procedures nat_cancel_factor for
   918 cancelling common factor from =, <, <= (in)equalities over natural
   919 sums; nat_cancel contains both kinds of procedures, it is installed by
   920 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   921 
   922 * HOL/simplifier: terms of the form
   923   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   924   are rewritten to
   925   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   926   and those of the form
   927   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   928   are rewritten to
   929   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   930 
   931 * HOL/datatype
   932   Each datatype `t' now comes with a theorem `split_t_case' of the form
   933 
   934   P(t_case f1 ... fn x) =
   935      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   936         ...
   937        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   938      )
   939 
   940   and a theorem `split_t_case_asm' of the form
   941 
   942   P(t_case f1 ... fn x) =
   943     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   944         ...
   945        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   946      )
   947   which can be added to a simpset via `addsplits'. The existing theorems
   948   expand_list_case and expand_option_case have been renamed to
   949   split_list_case and split_option_case.
   950 
   951 * HOL/Arithmetic:
   952   - `pred n' is automatically converted to `n-1'.
   953     Users are strongly encouraged not to use `pred' any longer,
   954     because it will disappear altogether at some point.
   955   - Users are strongly encouraged to write "0 < n" rather than
   956     "n ~= 0". Theorems and proof tools have been modified towards this
   957     `standard'.
   958 
   959 * HOL/Lists:
   960   the function "set_of_list" has been renamed "set" (and its theorems too);
   961   the function "nth" now takes its arguments in the reverse order and
   962   has acquired the infix notation "!" as in "xs!n".
   963 
   964 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
   965 
   966 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
   967   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
   968 
   969 * HOL/record: extensible records with schematic structural subtyping
   970 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
   971 still lacks various theorems and concrete record syntax;
   972 
   973 
   974 *** HOLCF ***
   975 
   976 * removed "axioms" and "generated by" sections;
   977 
   978 * replaced "ops" section by extended "consts" section, which is capable of
   979   handling the continuous function space "->" directly;
   980 
   981 * domain package:
   982   . proves theorems immediately and stores them in the theory,
   983   . creates hierachical name space,
   984   . now uses normal mixfix annotations (instead of cinfix...),
   985   . minor changes to some names and values (for consistency),
   986   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
   987   . separator between mutual domain defs: changed "," to "and",
   988   . improved handling of sort constraints;  now they have to
   989     appear on the left-hand side of the equations only;
   990 
   991 * fixed LAM <x,y,zs>.b syntax;
   992 
   993 * added extended adm_tac to simplifier in HOLCF -- can now discharge
   994 adm (%x. P (t x)), where P is chainfinite and t continuous;
   995 
   996 
   997 *** FOL and ZF ***
   998 
   999 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1000   with `addloop' of the simplifier to faciliate case splitting in premises.
  1001 
  1002 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1003 in HOL, they strip ALL and --> from proved theorems;
  1004 
  1005 
  1006 
  1007 New in Isabelle94-8 (May 1997)
  1008 ------------------------------
  1009 
  1010 *** General Changes ***
  1011 
  1012 * new utilities to build / run / maintain Isabelle etc. (in parts
  1013 still somewhat experimental); old Makefiles etc. still functional;
  1014 
  1015 * new 'Isabelle System Manual';
  1016 
  1017 * INSTALL text, together with ./configure and ./build scripts;
  1018 
  1019 * reimplemented type inference for greater efficiency, better error
  1020 messages and clean internal interface;
  1021 
  1022 * prlim command for dealing with lots of subgoals (an easier way of
  1023 setting goals_limit);
  1024 
  1025 
  1026 *** Syntax ***
  1027 
  1028 * supports alternative (named) syntax tables (parser and pretty
  1029 printer); internal interface is provided by add_modesyntax(_i);
  1030 
  1031 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1032 be used in conjunction with the Isabelle symbol font; uses the
  1033 "symbols" syntax table;
  1034 
  1035 * added token_translation interface (may translate name tokens in
  1036 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1037 the current print_mode); IMPORTANT: user print translation functions
  1038 are responsible for marking newly introduced bounds
  1039 (Syntax.mark_boundT);
  1040 
  1041 * token translations for modes "xterm" and "xterm_color" that display
  1042 names in bold, underline etc. or colors (which requires a color
  1043 version of xterm);
  1044 
  1045 * infixes may now be declared with names independent of their syntax;
  1046 
  1047 * added typed_print_translation (like print_translation, but may
  1048 access type of constant);
  1049 
  1050 
  1051 *** Classical Reasoner ***
  1052 
  1053 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1054 some limitations.  Blast_tac...
  1055   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1056   + ignores elimination rules that don't have the correct format
  1057         (the conclusion MUST be a formula variable)
  1058   + ignores types, which can make HOL proofs fail
  1059   + rules must not require higher-order unification, e.g. apply_type in ZF
  1060     [message "Function Var's argument not a bound variable" relates to this]
  1061   + its proof strategy is more general but can actually be slower
  1062 
  1063 * substitution with equality assumptions no longer permutes other
  1064 assumptions;
  1065 
  1066 * minor changes in semantics of addafter (now called addaltern); renamed
  1067 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1068 (and access functions for it);
  1069 
  1070 * improved combination of classical reasoner and simplifier:
  1071   + functions for handling clasimpsets
  1072   + improvement of addss: now the simplifier is called _after_ the
  1073     safe steps.
  1074   + safe variant of addss called addSss: uses safe simplifications
  1075     _during_ the safe steps. It is more complete as it allows multiple
  1076     instantiations of unknowns (e.g. with slow_tac).
  1077 
  1078 *** Simplifier ***
  1079 
  1080 * added interface for simplification procedures (functions that
  1081 produce *proven* rewrite rules on the fly, depending on current
  1082 redex);
  1083 
  1084 * ordering on terms as parameter (used for ordered rewriting);
  1085 
  1086 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1087 
  1088 * the solver is now split into a safe and an unsafe part.
  1089 This should be invisible for the normal user, except that the
  1090 functions setsolver and addsolver have been renamed to setSolver and
  1091 addSolver; added safe_asm_full_simp_tac;
  1092 
  1093 
  1094 *** HOL ***
  1095 
  1096 * a generic induction tactic `induct_tac' which works for all datatypes and
  1097 also for type `nat';
  1098 
  1099 * a generic case distinction tactic `exhaust_tac' which works for all
  1100 datatypes and also for type `nat';
  1101 
  1102 * each datatype comes with a function `size';
  1103 
  1104 * patterns in case expressions allow tuple patterns as arguments to
  1105 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1106 
  1107 * primrec now also works with type nat;
  1108 
  1109 * recdef: a new declaration form, allows general recursive functions to be
  1110 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1111 
  1112 * the constant for negation has been renamed from "not" to "Not" to
  1113 harmonize with FOL, ZF, LK, etc.;
  1114 
  1115 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1116 infinite lists;
  1117 
  1118 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1119 
  1120 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1121 problems in commutative rings, using axiomatic type classes for + and *;
  1122 
  1123 * more examples in HOL/MiniML and HOL/Auth;
  1124 
  1125 * more default rewrite rules for quantifiers, union/intersection;
  1126 
  1127 * a new constant `arbitrary == @x.False';
  1128 
  1129 * HOLCF/IOA replaces old HOL/IOA;
  1130 
  1131 * HOLCF changes: derived all rules and arities
  1132   + axiomatic type classes instead of classes
  1133   + typedef instead of faking type definitions
  1134   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1135   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1136   + eliminated the types void, one, tr
  1137   + use unit lift and bool lift (with translations) instead of one and tr
  1138   + eliminated blift from Lift3.thy (use Def instead of blift)
  1139   all eliminated rules are derived as theorems --> no visible changes ;
  1140 
  1141 
  1142 *** ZF ***
  1143 
  1144 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1145 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1146 as ZF_cs addSIs [equalityI];
  1147 
  1148 
  1149 
  1150 New in Isabelle94-7 (November 96)
  1151 ---------------------------------
  1152 
  1153 * allowing negative levels (as offsets) in prlev and choplev;
  1154 
  1155 * super-linear speedup for large simplifications;
  1156 
  1157 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1158 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1159 FAIL); can suppress it using the command Delsimps (ex_simps @
  1160 all_simps); De Morgan laws are also now included, by default;
  1161 
  1162 * improved printing of ==>  :  ~:
  1163 
  1164 * new object-logic "Sequents" adds linear logic, while replacing LK
  1165 and Modal (thanks to Sara Kalvala);
  1166 
  1167 * HOL/Auth: correctness proofs for authentication protocols;
  1168 
  1169 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1170 examples on HOL/Auth);
  1171 
  1172 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1173 the rewriter and classical reasoner simultaneously;
  1174 
  1175 * function uresult no longer returns theorems in "standard" format;
  1176 regain previous version by: val uresult = standard o uresult;
  1177 
  1178 
  1179 
  1180 New in Isabelle94-6
  1181 -------------------
  1182 
  1183 * oracles -- these establish an interface between Isabelle and trusted
  1184 external reasoners, which may deliver results as theorems;
  1185 
  1186 * proof objects (in particular record all uses of oracles);
  1187 
  1188 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1189 
  1190 * "constdefs" section in theory files;
  1191 
  1192 * "primrec" section (HOL) no longer requires names;
  1193 
  1194 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1195 
  1196 
  1197 
  1198 New in Isabelle94-5
  1199 -------------------
  1200 
  1201 * reduced space requirements;
  1202 
  1203 * automatic HTML generation from theories;
  1204 
  1205 * theory files no longer require "..." (quotes) around most types;
  1206 
  1207 * new examples, including two proofs of the Church-Rosser theorem;
  1208 
  1209 * non-curried (1994) version of HOL is no longer distributed;
  1210 
  1211 
  1212 
  1213 New in Isabelle94-4
  1214 -------------------
  1215 
  1216 * greatly reduced space requirements;
  1217 
  1218 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1219 
  1220 * searchable theorem database (see the section "Retrieving theorems" on
  1221 page 8 of the Reference Manual);
  1222 
  1223 * new examples, including Grabczewski's monumental case study of the
  1224 Axiom of Choice;
  1225 
  1226 * The previous version of HOL renamed to Old_HOL;
  1227 
  1228 * The new version of HOL (previously called CHOL) uses a curried syntax
  1229 for functions.  Application looks like f a b instead of f(a,b);
  1230 
  1231 * Mutually recursive inductive definitions finally work in HOL;
  1232 
  1233 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1234 translates to the operator "split";
  1235 
  1236 
  1237 
  1238 New in Isabelle94-3
  1239 -------------------
  1240 
  1241 * new infix operator, addss, allowing the classical reasoner to
  1242 perform simplification at each step of its search.  Example:
  1243         fast_tac (cs addss ss)
  1244 
  1245 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1246 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1247 look like (a,b) instead of <a,b>;
  1248 
  1249 * PLEASE NOTE: CHOL will eventually replace HOL!
  1250 
  1251 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1252 It translates to the operator "split".  A new theory of integers is available;
  1253 
  1254 * In ZF, integer numerals now denote two's-complement binary integers.
  1255 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1256 
  1257 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1258 of the Axiom of Choice;
  1259 
  1260 
  1261 
  1262 New in Isabelle94-2
  1263 -------------------
  1264 
  1265 * Significantly faster resolution;
  1266 
  1267 * the different sections in a .thy file can now be mixed and repeated
  1268 freely;
  1269 
  1270 * Database of theorems for FOL, HOL and ZF.  New
  1271 commands including qed, qed_goal and bind_thm store theorems in the database.
  1272 
  1273 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1274 a given theory (thms_of), or find out what theory a theorem was proved in
  1275 (theory_of_thm);
  1276 
  1277 * Bugs fixed in the inductive definition and datatype packages;
  1278 
  1279 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1280 and HOL_dup_cs obsolete;
  1281 
  1282 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1283 have been removed;
  1284 
  1285 * Simpler definition of function space in ZF;
  1286 
  1287 * new results about cardinal and ordinal arithmetic in ZF;
  1288 
  1289 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1290 types;
  1291 
  1292 
  1293 $Id$