NEWS
author paulson
Thu May 04 12:29:18 2000 +0200 (2000-05-04)
changeset 8788 518a5450ab6d
parent 8736 0bfd6678a5fa
child 8832 bcceda950cd0
permissions -rw-r--r--
simprocs
     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: simplification of natural numbers is much changed.  To partly recover
    11        the old behaviour (e.g. to prevent n+n rewriting to #2*n) type
    12 		Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
    13 		Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
    14 
    15 * HOL: the constant for f``x is now "image" rather than "op ``";
    16 
    17 * HOL: the cartesian product is now "<*>" instead of "Times"; the
    18 lexicographic product is now "<*lex*>" instead of "**";
    19 
    20 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    21 
    22 * HOL: simplification no longer dives into case-expressions
    23 
    24 * HOL: the recursion equations generated by 'recdef' are now called
    25 f.simps instead of f.rules;
    26 
    27 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    28 
    29 * LaTeX: several improvements of isabelle.sty;
    30 
    31 
    32 *** Document preparation ***
    33 
    34 * isatool mkdir provides easy setup of Isabelle session directories,
    35 including proper document sources;
    36 
    37 * generated LaTeX sources are now deleted after successful run
    38 (isatool document -c); may retain a copy somewhere else via -D option
    39 of isatool usedir;
    40 
    41 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    42 style files, achieving self-contained LaTeX sources;
    43 
    44 * old-style theories now produce (crude) LaTeX output as well;
    45 
    46 
    47 *** Isar ***
    48 
    49 * Pure: local results and corresponding term bindings are now subject
    50 to Hindley-Milner polymorphism (similar to ML); this accommodates
    51 incremental type-inference nicely;
    52 
    53 * Pure: new 'obtain' language element supports generalized existence
    54 reasoning;
    55 
    56 * Pure: new calculational elements 'moreover' and 'ultimately' support
    57 plain accumulation of results, without applying any rules yet;
    58 
    59 * Pure: scalable support for case-analysis type proofs: new 'case'
    60 language element refers to local contexts symbolically, as produced by
    61 certain proof methods; internally, case names are attached to theorems
    62 as "tags";
    63 
    64 * Pure now provides its own version of intro/elim/dest attributes;
    65 useful for building new logics, but beware of confusion with the
    66 Provers/classical ones;
    67 
    68 * Provers: splitter support (via 'split' attribute and 'simp' method
    69 modifier); 'simp' method: 'only:' modifier removes loopers as well
    70 (including splits);
    71 
    72 * HOL: new proof method 'cases' and improved version of 'induct' now
    73 support named cases; major packages (inductive, datatype, primrec,
    74 recdef) support case names and properly name parameters;
    75 
    76 * HOL: removed 'case_split' thm binding, should use 'cases' proof
    77 method anyway;
    78 
    79 * names of theorems etc. may be natural numbers as well;
    80 
    81 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
    82 
    83 * 'pr' command: optional goals_limit argument;
    84 
    85 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
    86 additional print modes to be specified; e.g. "pr(latex)" will print
    87 proof state according to the Isabelle LaTeX style;
    88 
    89 * improved support for emulating tactic scripts, including proof
    90 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
    91 'induct_tac' (for HOL datatypes);
    92 
    93 * simplified (more robust) goal selection of proof methods: 1st goal,
    94 all goals, or explicit goal specifier (tactic emulation); thus 'proof
    95 method scripts' have to be in depth-first order;
    96 
    97 * tuned 'let' syntax: replace 'as' keyword by 'and';
    98 
    99 * theory command 'hide' removes declarations from class/type/const
   100 name spaces;
   101 
   102 
   103 *** HOL ***
   104 
   105 * HOL/Algebra: new theory of rings and univariate polynomials, by
   106 Clemens Ballarin;
   107 
   108 * HOL/record: fixed select-update simplification procedure to handle
   109 extended records as well; admit "r" as field name;
   110 
   111 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
   112 Arithmetic, by Thomas M Rasmussen;
   113 
   114 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
   115 basically a generalized version of de-Bruijn representation; very
   116 useful in avoiding lifting all operations;
   117 
   118 * greatly improved simplification involving numerals of type "nat", e.g.
   119    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   120    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k;
   121 
   122 * new version of "case_tac" subsumes both boolean case split and
   123 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   124 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   125 
   126 * simplification no longer dives into case-expressions: only the selector
   127 expression is simplified, but not the remaining arms. To enable full
   128 simplification of case-expressions for datatype t, you need to remove
   129 t.weak_case_cong from the simpset, either permanently
   130 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   131 
   132 * the recursion equations generated by 'recdef' for function 'f' are
   133 now called f.simps instead of f.rules; if all termination conditions
   134 are proved automatically, these simplification rules are added to the
   135 simpset, as in primrec; rules may be named individually as well,
   136 resulting in a separate list of theorems for each equation;
   137 
   138 
   139 *** General ***
   140 
   141 * improved name spaces: ambiguous output is qualified; support for
   142 hiding of names;
   143 
   144 * compression of ML heaps images may now be controlled via -c option
   145 of isabelle and isatool usedir (currently only observed by Poly/ML);
   146 
   147 * ML: new combinators |>> and |>>> for incremental transformations
   148 with secondary results (e.g. certain theory extensions):
   149 
   150 
   151 
   152 New in Isabelle99 (October 1999)
   153 --------------------------------
   154 
   155 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   156 
   157 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   158 are no longer simplified.  (This allows the simplifier to unfold recursive
   159 functional programs.)  To restore the old behaviour, declare
   160 
   161     Delcongs [if_weak_cong];
   162 
   163 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   164 complement;
   165 
   166 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   167 
   168 * HOL/datatype: mutual_induct_tac no longer exists --
   169   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   170 
   171 * HOL/typedef: fixed type inference for representing set; type
   172 arguments now have to occur explicitly on the rhs as type constraints;
   173 
   174 * ZF: The con_defs part of an inductive definition may no longer refer
   175 to constants declared in the same theory;
   176 
   177 * HOL, ZF: the function mk_cases, generated by the inductive
   178 definition package, has lost an argument.  To simplify its result, it
   179 uses the default simpset instead of a supplied list of theorems.
   180 
   181 * HOL/List: the constructors of type list are now Nil and Cons;
   182 
   183 * Simplifier: the type of the infix ML functions
   184         setSSolver addSSolver setSolver addSolver
   185 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   186 for packaging solvers. A solver is created via
   187         mk_solver: string -> (thm list -> int -> tactic) -> solver
   188 where the string argument is only a comment.
   189 
   190 
   191 *** Proof tools ***
   192 
   193 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   194 decision procedure for linear arithmetic. Currently it is used for
   195 types `nat', `int', and `real' in HOL (see below); it can, should and
   196 will be instantiated for other types and logics as well.
   197 
   198 * The simplifier now accepts rewrite rules with flexible heads, eg
   199      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   200   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   201   matching.
   202 
   203 
   204 *** General ***
   205 
   206 * New Isabelle/Isar subsystem provides an alternative to traditional
   207 tactical theorem proving; together with the ProofGeneral/isar user
   208 interface it offers an interactive environment for developing human
   209 readable proof documents (Isar == Intelligible semi-automated
   210 reasoning); for further information see isatool doc isar-ref,
   211 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   212 
   213 * improved presentation of theories: better HTML markup (including
   214 colors), graph views in several sizes; isatool usedir now provides a
   215 proper interface for user theories (via -P option); actual document
   216 preparation based on (PDF)LaTeX is available as well (for new-style
   217 theories only); see isatool doc system for more information;
   218 
   219 * native support for Proof General, both for classic Isabelle and
   220 Isabelle/Isar;
   221 
   222 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   223 using the graph browser tool;
   224 
   225 * Isabelle manuals now also available as PDF;
   226 
   227 * theory loader rewritten from scratch (may not be fully
   228 bug-compatible); old loadpath variable has been replaced by show_path,
   229 add_path, del_path, reset_path functions; new operations such as
   230 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   231 isatool doc ref);
   232 
   233 * improved isatool install: option -k creates KDE application icon,
   234 option -p DIR installs standalone binaries;
   235 
   236 * added ML_PLATFORM setting (useful for cross-platform installations);
   237 more robust handling of platform specific ML images for SML/NJ;
   238 
   239 * the settings environment is now statically scoped, i.e. it is never
   240 created again in sub-processes invoked from isabelle, isatool, or
   241 Isabelle;
   242 
   243 * path element specification '~~' refers to '$ISABELLE_HOME';
   244 
   245 * in locales, the "assumes" and "defines" parts may be omitted if
   246 empty;
   247 
   248 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   249 long arrows);
   250 
   251 * new print_mode "HTML";
   252 
   253 * new flag show_tags controls display of tags of theorems (which are
   254 basically just comments that may be attached by some tools);
   255 
   256 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   257 mode and goal output format:
   258 
   259 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   260 244c244
   261 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   262 ---
   263 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   264 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   265 181c181
   266 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   267 ---
   268 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   269 
   270 * function bind_thms stores lists of theorems (cf. bind_thm);
   271 
   272 * new shorthand tactics ftac, eatac, datac, fatac;
   273 
   274 * qed (and friends) now accept "" as result name; in that case the
   275 theorem is not stored, but proper checks and presentation of the
   276 result still apply;
   277 
   278 * theorem database now also indexes constants "Trueprop", "all",
   279 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   280 
   281 
   282 *** HOL ***
   283 
   284 ** HOL arithmetic **
   285 
   286 * There are now decision procedures for linear arithmetic over nat and
   287 int:
   288 
   289 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   290 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   291 are treated as atomic; subformulae not involving type `nat' or `int'
   292 are ignored; quantified subformulae are ignored unless they are
   293 positive universal or negative existential. The tactic has to be
   294 invoked by hand and can be a little bit slow. In particular, the
   295 running time is exponential in the number of occurrences of `min' and
   296 `max', and `-' on `nat'.
   297 
   298 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   299 (negated) (in)equalities among the premises and the conclusion into
   300 account (i.e. no compound formulae) and does not know about `min' and
   301 `max', and `-' on `nat'. It is fast and is used automatically by the
   302 simplifier.
   303 
   304 NB: At the moment, these decision procedures do not cope with mixed
   305 nat/int formulae where the two parts interact, such as `m < n ==>
   306 int(m) < int(n)'.
   307 
   308 * HOL/Numeral provides a generic theory of numerals (encoded
   309 efficiently as bit strings); setup for types nat/int/real is in place;
   310 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   311 int, existing theories and proof scripts may require a few additional
   312 type constraints;
   313 
   314 * integer division and remainder can now be performed on constant
   315 arguments;
   316 
   317 * many properties of integer multiplication, division and remainder
   318 are now available;
   319 
   320 * An interface to the Stanford Validity Checker (SVC) is available through the
   321 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   322 are proved automatically.  SVC must be installed separately, and its results
   323 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   324 invocation of the underlying oracle).  For SVC see
   325   http://verify.stanford.edu/SVC
   326 
   327 * IsaMakefile: the HOL-Real target now builds an actual image;
   328 
   329 
   330 ** HOL misc **
   331 
   332 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   333 (in Isabelle/Isar) -- by Gertrud Bauer;
   334 
   335 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   336 analysis for assembly languages with subtypes;
   337 
   338 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   339 -- avoids syntactic ambiguities and treats state, transition, and
   340 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   341 changed syntax and (many) tactics;
   342 
   343 * HOL/inductive: Now also handles more general introduction rules such
   344   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   345   theorems are now maintained within the theory (maintained via the
   346   "mono" attribute);
   347 
   348 * HOL/datatype: Now also handles arbitrarily branching datatypes
   349   (using function types) such as
   350 
   351   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   352 
   353 * HOL/record: record_simproc (part of the default simpset) takes care
   354 of selectors applied to updated records; record_split_tac is no longer
   355 part of the default claset; update_defs may now be removed from the
   356 simpset in many cases; COMPATIBILITY: old behavior achieved by
   357 
   358   claset_ref () := claset() addSWrapper record_split_wrapper;
   359   Delsimprocs [record_simproc]
   360 
   361 * HOL/typedef: fixed type inference for representing set; type
   362 arguments now have to occur explicitly on the rhs as type constraints;
   363 
   364 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   365 names rather than an ML expression;
   366 
   367 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   368 supplied later.  Program schemes can be defined, such as
   369     "While B C s = (if B s then While B C (C s) else s)"
   370 where the well-founded relation can be chosen after B and C have been given.
   371 
   372 * HOL/List: the constructors of type list are now Nil and Cons;
   373 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   374 course, ML tools referring to List.list.op # etc. have to be adapted;
   375 
   376 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   377 disabled by default; run isabelle with option -m HOL to get back to
   378 the original Gordon/HOL-style output;
   379 
   380 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   381 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   382 
   383 * HOL basic syntax simplified (more orthogonal): all variants of
   384 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   385 Eps operator is provided as well: "SOME x. P[x]";
   386 
   387 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   388 
   389 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   390 thus available for user theories;
   391 
   392 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   393 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   394 time;
   395 
   396 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   397 several times and then mp;
   398 
   399 
   400 *** LK ***
   401 
   402 * the notation <<...>> is now available as a notation for sequences of
   403 formulas;
   404 
   405 * the simplifier is now installed
   406 
   407 * the axiom system has been generalized (thanks to Soren Heilmann)
   408 
   409 * the classical reasoner now has a default rule database
   410 
   411 
   412 *** ZF ***
   413 
   414 * new primrec section allows primitive recursive functions to be given
   415 directly (as in HOL) over datatypes and the natural numbers;
   416 
   417 * new tactics induct_tac and exhaust_tac for induction (or case
   418 analysis) over datatypes and the natural numbers;
   419 
   420 * the datatype declaration of type T now defines the recursor T_rec;
   421 
   422 * simplification automatically does freeness reasoning for datatype
   423 constructors;
   424 
   425 * automatic type-inference, with AddTCs command to insert new
   426 type-checking rules;
   427 
   428 * datatype introduction rules are now added as Safe Introduction rules
   429 to the claset;
   430 
   431 * the syntax "if P then x else y" is now available in addition to
   432 if(P,x,y);
   433 
   434 
   435 *** Internal programming interfaces ***
   436 
   437 * tuned simplifier trace output; new flag debug_simp;
   438 
   439 * structures Vartab / Termtab (instances of TableFun) offer efficient
   440 tables indexed by indexname_ord / term_ord (compatible with aconv);
   441 
   442 * AxClass.axclass_tac lost the theory argument;
   443 
   444 * tuned current_goals_markers semantics: begin / end goal avoids
   445 printing empty lines;
   446 
   447 * removed prs and prs_fn hook, which was broken because it did not
   448 include \n in its semantics, forcing writeln to add one
   449 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   450 string -> unit if you really want to output text without newline;
   451 
   452 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   453 plain output, interface builders may have to enable 'isabelle_font'
   454 mode to get Isabelle font glyphs as before;
   455 
   456 * refined token_translation interface; INCOMPATIBILITY: output length
   457 now of type real instead of int;
   458 
   459 * theory loader actions may be traced via new ThyInfo.add_hook
   460 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   461 your own database of information attached to *whole* theories -- as
   462 opposed to intra-theory data slots offered via TheoryDataFun;
   463 
   464 * proper handling of dangling sort hypotheses (at last!);
   465 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   466 extra sort hypotheses that can be witnessed from the type signature;
   467 the force_strip_shyps flag is gone, any remaining shyps are simply
   468 left in the theorem (with a warning issued by strip_shyps_warning);
   469 
   470 
   471 
   472 New in Isabelle98-1 (October 1998)
   473 ----------------------------------
   474 
   475 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   476 
   477 * several changes of automated proof tools;
   478 
   479 * HOL: major changes to the inductive and datatype packages, including
   480 some minor incompatibilities of theory syntax;
   481 
   482 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   483 called `inj_on';
   484 
   485 * HOL: removed duplicate thms in Arith:
   486   less_imp_add_less  should be replaced by  trans_less_add1
   487   le_imp_add_le      should be replaced by  trans_le_add1
   488 
   489 * HOL: unary minus is now overloaded (new type constraints may be
   490 required);
   491 
   492 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   493 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   494 now taken as an integer constant.
   495 
   496 * Pure: ML function 'theory_of' renamed to 'theory';
   497 
   498 
   499 *** Proof tools ***
   500 
   501 * Simplifier:
   502   1. Asm_full_simp_tac is now more aggressive.
   503      1. It will sometimes reorient premises if that increases their power to
   504         simplify.
   505      2. It does no longer proceed strictly from left to right but may also
   506         rotate premises to achieve further simplification.
   507      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   508      old Asm_full_simp_tac in that it does not rotate premises.
   509   2. The simplifier now knows a little bit about nat-arithmetic.
   510 
   511 * Classical reasoner: wrapper mechanism for the classical reasoner now
   512 allows for selected deletion of wrappers, by introduction of names for
   513 wrapper functionals.  This implies that addbefore, addSbefore,
   514 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   515 and that adding two tactics with the same name overwrites the first
   516 one (emitting a warning).
   517   type wrapper = (int -> tactic) -> (int -> tactic)
   518   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   519   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   520   delWrapper, delSWrapper: claset *  string            -> claset
   521   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   522 
   523 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   524 semantics; addbefore now affects only the unsafe part of step_tac
   525 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   526 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   527 by Force_tac;
   528 
   529 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   530 compWrapper; added safe wrapper (and access functions for it);
   531 
   532 * HOL/split_all_tac is now much faster and fails if there is nothing
   533 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   534 and the names of the automatically generated variables have changed.
   535 split_all_tac has moved within claset() from unsafe wrappers to safe
   536 wrappers, which means that !!-bound variables are split much more
   537 aggressively, and safe_tac and clarify_tac now split such variables.
   538 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   539 Note: the same holds for record_split_tac, which does the job of
   540 split_all_tac for record fields.
   541 
   542 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   543 permanently to the default simpset using Addsplits just like
   544 Addsimps. They can be removed via Delsplits just like
   545 Delsimps. Lower-case versions are also available.
   546 
   547 * HOL/Simplifier: The rule split_if is now part of the default
   548 simpset. This means that the simplifier will eliminate all occurrences
   549 of if-then-else in the conclusion of a goal. To prevent this, you can
   550 either remove split_if completely from the default simpset by
   551 `Delsplits [split_if]' or remove it in a specific call of the
   552 simplifier using `... delsplits [split_if]'.  You can also add/delete
   553 other case splitting rules to/from the default simpset: every datatype
   554 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   555 t is the name of the datatype).
   556 
   557 * Classical reasoner / Simplifier combination: new force_tac (and
   558 derivatives Force_tac, force) combines rewriting and classical
   559 reasoning (and whatever other tools) similarly to auto_tac, but is
   560 aimed to solve the given subgoal completely.
   561 
   562 
   563 *** General ***
   564 
   565 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   566 and `goalw': the theory is no longer needed as an explicit argument -
   567 the current theory context is used; assumptions are no longer returned
   568 at the ML-level unless one of them starts with ==> or !!; it is
   569 recommended to convert to these new commands using isatool fixgoal
   570 (backup your sources first!);
   571 
   572 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   573 the current theory context, and 'theory' to lookup stored theories;
   574 
   575 * new theory section 'locale' for declaring constants, assumptions and
   576 definitions that have local scope;
   577 
   578 * new theory section 'nonterminals' for purely syntactic types;
   579 
   580 * new theory section 'setup' for generic ML setup functions
   581 (e.g. package initialization);
   582 
   583 * the distribution now includes Isabelle icons: see
   584 lib/logo/isabelle-{small,tiny}.xpm;
   585 
   586 * isatool install - install binaries with absolute references to
   587 ISABELLE_HOME/bin;
   588 
   589 * isatool logo -- create instances of the Isabelle logo (as EPS);
   590 
   591 * print mode 'emacs' reserved for Isamode;
   592 
   593 * support multiple print (ast) translations per constant name;
   594 
   595 * theorems involving oracles are now printed with a suffixed [!];
   596 
   597 
   598 *** HOL ***
   599 
   600 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   601 
   602 * HOL/inductive package reorganized and improved: now supports mutual
   603 definitions such as
   604 
   605   inductive EVEN ODD
   606     intrs
   607       null "0 : EVEN"
   608       oddI "n : EVEN ==> Suc n : ODD"
   609       evenI "n : ODD ==> Suc n : EVEN"
   610 
   611 new theorem list "elims" contains an elimination rule for each of the
   612 recursive sets; inductive definitions now handle disjunctive premises
   613 correctly (also ZF);
   614 
   615 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   616 "mutual_induct" no longer exists - the induction rule is always
   617 contained in "induct";
   618 
   619 
   620 * HOL/datatype package re-implemented and greatly improved: now
   621 supports mutually recursive datatypes such as
   622 
   623   datatype
   624     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   625             | SUM ('a aexp) ('a aexp)
   626             | DIFF ('a aexp) ('a aexp)
   627             | NUM 'a
   628   and
   629     'a bexp = LESS ('a aexp) ('a aexp)
   630             | AND ('a bexp) ('a bexp)
   631             | OR ('a bexp) ('a bexp)
   632 
   633 as well as indirectly recursive datatypes such as
   634 
   635   datatype
   636     ('a, 'b) term = Var 'a
   637                   | App 'b ((('a, 'b) term) list)
   638 
   639 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   640 induction on mutually / indirectly recursive datatypes.
   641 
   642 Primrec equations are now stored in theory and can be accessed via
   643 <function_name>.simps.
   644 
   645 INCOMPATIBILITIES:
   646 
   647   - Theories using datatypes must now have theory Datatype as an
   648     ancestor.
   649   - The specific <typename>.induct_tac no longer exists - use the
   650     generic induct_tac instead.
   651   - natE has been renamed to nat.exhaust - use exhaust_tac
   652     instead of res_inst_tac ... natE. Note that the variable
   653     names in nat.exhaust differ from the names in natE, this
   654     may cause some "fragile" proofs to fail.
   655   - The theorems split_<typename>_case and split_<typename>_case_asm
   656     have been renamed to <typename>.split and <typename>.split_asm.
   657   - Since default sorts of type variables are now handled correctly,
   658     some datatype definitions may have to be annotated with explicit
   659     sort constraints.
   660   - Primrec definitions no longer require function name and type
   661     of recursive argument.
   662 
   663 Consider using isatool fixdatatype to adapt your theories and proof
   664 scripts to the new package (backup your sources first!).
   665 
   666 
   667 * HOL/record package: considerably improved implementation; now
   668 includes concrete syntax for record types, terms, updates; theorems
   669 for surjective pairing and splitting !!-bound record variables; proof
   670 support is as follows:
   671 
   672   1) standard conversions (selectors or updates applied to record
   673 constructor terms) are part of the standard simpset;
   674 
   675   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   676 made part of standard simpset and claset via addIffs;
   677 
   678   3) a tactic for record field splitting (record_split_tac) is part of
   679 the standard claset (addSWrapper);
   680 
   681 To get a better idea about these rules you may retrieve them via
   682 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   683 the name of your record type.
   684 
   685 The split tactic 3) conceptually simplifies by the following rule:
   686 
   687   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   688 
   689 Thus any record variable that is bound by meta-all will automatically
   690 blow up into some record constructor term, consequently the
   691 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   692 solve record problems automatically.
   693 
   694 
   695 * reorganized the main HOL image: HOL/Integ and String loaded by
   696 default; theory Main includes everything;
   697 
   698 * automatic simplification of integer sums and comparisons, using cancellation;
   699 
   700 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   701 
   702 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   703 
   704 * many new identities for unions, intersections, set difference, etc.;
   705 
   706 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   707 called split_if, split_split, split_sum_case and split_nat_case (to go
   708 with add/delsplits);
   709 
   710 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   711 (?x::unit) = (); this is made part of the default simpset, which COULD
   712 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   713 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   714 unit_abs_eta_conv is added in order to counter the effect of
   715 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   716 %u.f();
   717 
   718 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   719 makes more sense);
   720 
   721 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   722   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   723   disjointness reasoning but breaking a few old proofs.
   724 
   725 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   726 to 'converse' from 'inverse' (for compatibility with ZF and some
   727 literature);
   728 
   729 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   730 the well-founded relation;
   731 
   732 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   733     Compl A.  The "Compl" syntax remains available as input syntax for this
   734     release ONLY.
   735 
   736 * HOL/Update: new theory of function updates:
   737     f(a:=b) == %x. if x=a then b else f x
   738 may also be iterated as in f(a:=b,c:=d,...);
   739 
   740 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   741 
   742 * HOL/List:
   743   - new function list_update written xs[i:=v] that updates the i-th
   744     list position. May also be iterated as in xs[i:=a,j:=b,...].
   745   - new function `upt' written [i..j(] which generates the list
   746     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   747     bound write [i..j], which is a shorthand for [i..j+1(].
   748   - new lexicographic orderings and corresponding wellfoundedness theorems.
   749 
   750 * HOL/Arith:
   751   - removed 'pred' (predecessor) function;
   752   - generalized some theorems about n-1;
   753   - many new laws about "div" and "mod";
   754   - new laws about greatest common divisors (see theory ex/Primes);
   755 
   756 * HOL/Relation: renamed the relational operator r^-1 "converse"
   757 instead of "inverse";
   758 
   759 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   760   of the multiset ordering;
   761 
   762 * directory HOL/Real: a construction of the reals using Dedekind cuts
   763   (not included by default);
   764 
   765 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   766 
   767 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   768   programs, i.e. different program variables may have different types.
   769 
   770 * calling (stac rew i) now fails if "rew" has no effect on the goal
   771   [previously, this check worked only if the rewrite rule was unconditional]
   772   Now rew can involve either definitions or equalities (either == or =).
   773 
   774 
   775 *** ZF ***
   776 
   777 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   778   only the theorems proved on ZF.ML;
   779 
   780 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   781   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   782   disjointness reasoning but breaking a few old proofs.
   783 
   784 * ZF/Update: new theory of function updates
   785     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   786   may also be iterated as in f(a:=b,c:=d,...);
   787 
   788 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   789 
   790 * calling (stac rew i) now fails if "rew" has no effect on the goal
   791   [previously, this check worked only if the rewrite rule was unconditional]
   792   Now rew can involve either definitions or equalities (either == or =).
   793 
   794 * case_tac provided for compatibility with HOL
   795     (like the old excluded_middle_tac, but with subgoals swapped)
   796 
   797 
   798 *** Internal programming interfaces ***
   799 
   800 * Pure: several new basic modules made available for general use, see
   801 also src/Pure/README;
   802 
   803 * improved the theory data mechanism to support encapsulation (data
   804 kind name replaced by private Object.kind, acting as authorization
   805 key); new type-safe user interface via functor TheoryDataFun; generic
   806 print_data function becomes basically useless;
   807 
   808 * removed global_names compatibility flag -- all theory declarations
   809 are qualified by default;
   810 
   811 * module Pure/Syntax now offers quote / antiquote translation
   812 functions (useful for Hoare logic etc. with implicit dependencies);
   813 see HOL/ex/Antiquote for an example use;
   814 
   815 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   816 cterm -> thm;
   817 
   818 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   819 subgoal;
   820 
   821 * Display.print_goals function moved to Locale.print_goals;
   822 
   823 * standard print function for goals supports current_goals_markers
   824 variable for marking begin of proof, end of proof, start of goal; the
   825 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   826 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   827 for example;
   828 
   829 
   830 
   831 New in Isabelle98 (January 1998)
   832 --------------------------------
   833 
   834 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   835 
   836 * changed lexical syntax of terms / types: dots made part of long
   837 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   838 
   839 * simpset (and claset) reference variable replaced by functions
   840 simpset / simpset_ref;
   841 
   842 * no longer supports theory aliases (via merge) and non-trivial
   843 implicit merge of thms' signatures;
   844 
   845 * most internal names of constants changed due to qualified names;
   846 
   847 * changed Pure/Sequence interface (see Pure/seq.ML);
   848 
   849 
   850 *** General Changes ***
   851 
   852 * hierachically structured name spaces (for consts, types, axms, thms
   853 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   854 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   855 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   856 long_names for fully qualified output names; NOTE: ML programs
   857 (special tactics, packages etc.) referring to internal names may have
   858 to be adapted to cope with fully qualified names; in case of severe
   859 backward campatibility problems try setting 'global_names' at compile
   860 time to have enrything declared within a flat name space; one may also
   861 fine tune name declarations in theories via the 'global' and 'local'
   862 section;
   863 
   864 * reimplemented the implicit simpset and claset using the new anytype
   865 data filed in signatures; references simpset:simpset ref etc. are
   866 replaced by functions simpset:unit->simpset and
   867 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   868 to patch your ML files accordingly;
   869 
   870 * HTML output now includes theory graph data for display with Java
   871 applet or isatool browser; data generated automatically via isatool
   872 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   873 
   874 * defs may now be conditional; improved rewrite_goals_tac to handle
   875 conditional equations;
   876 
   877 * defs now admits additional type arguments, using TYPE('a) syntax;
   878 
   879 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   880 creates a new theory node; implicit merge of thms' signatures is
   881 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   882 transfer:theory->thm->thm in (rare) cases;
   883 
   884 * improved handling of draft signatures / theories; draft thms (and
   885 ctyps, cterms) are automatically promoted to real ones;
   886 
   887 * slightly changed interfaces for oracles: admit many per theory, named
   888 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   889 
   890 * print_goals: optional output of const types (set show_consts and
   891 show_types);
   892 
   893 * improved output of warnings (###) and errors (***);
   894 
   895 * subgoal_tac displays a warning if the new subgoal has type variables;
   896 
   897 * removed old README and Makefiles;
   898 
   899 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   900 
   901 * removed obsolete init_pps and init_database;
   902 
   903 * deleted the obsolete tactical STATE, which was declared by
   904     fun STATE tacfun st = tacfun st st;
   905 
   906 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   907 (which abbreviates $HOME);
   908 
   909 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   910 use isatool fixseq to adapt your ML programs (this works for fully
   911 qualified references to the Sequence structure only!);
   912 
   913 * use_thy no longer requires writable current directory; it always
   914 reloads .ML *and* .thy file, if either one is out of date;
   915 
   916 
   917 *** Classical Reasoner ***
   918 
   919 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   920 tactics that use classical reasoning to simplify a subgoal without
   921 splitting it into several subgoals;
   922 
   923 * Safe_tac: like safe_tac but uses the default claset;
   924 
   925 
   926 *** Simplifier ***
   927 
   928 * added simplification meta rules:
   929     (asm_)(full_)simplify: simpset -> thm -> thm;
   930 
   931 * simplifier.ML no longer part of Pure -- has to be loaded by object
   932 logics (again);
   933 
   934 * added prems argument to simplification procedures;
   935 
   936 * HOL, FOL, ZF: added infix function `addsplits':
   937   instead of `<simpset> setloop (split_tac <thms>)'
   938   you can simply write `<simpset> addsplits <thms>'
   939 
   940 
   941 *** Syntax ***
   942 
   943 * TYPE('a) syntax for type reflection terms;
   944 
   945 * no longer handles consts with name "" -- declare as 'syntax' instead;
   946 
   947 * pretty printer: changed order of mixfix annotation preference (again!);
   948 
   949 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   950 
   951 
   952 *** HOL ***
   953 
   954 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   955   with `addloop' of the simplifier to faciliate case splitting in premises.
   956 
   957 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   958 
   959 * HOL/Auth: new protocol proofs including some for the Internet
   960   protocol TLS;
   961 
   962 * HOL/Map: new theory of `maps' a la VDM;
   963 
   964 * HOL/simplifier: simplification procedures nat_cancel_sums for
   965 cancelling out common nat summands from =, <, <= (in)equalities, or
   966 differences; simplification procedures nat_cancel_factor for
   967 cancelling common factor from =, <, <= (in)equalities over natural
   968 sums; nat_cancel contains both kinds of procedures, it is installed by
   969 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   970 
   971 * HOL/simplifier: terms of the form
   972   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   973   are rewritten to
   974   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   975   and those of the form
   976   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   977   are rewritten to
   978   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   979 
   980 * HOL/datatype
   981   Each datatype `t' now comes with a theorem `split_t_case' of the form
   982 
   983   P(t_case f1 ... fn x) =
   984      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   985         ...
   986        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   987      )
   988 
   989   and a theorem `split_t_case_asm' of the form
   990 
   991   P(t_case f1 ... fn x) =
   992     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   993         ...
   994        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   995      )
   996   which can be added to a simpset via `addsplits'. The existing theorems
   997   expand_list_case and expand_option_case have been renamed to
   998   split_list_case and split_option_case.
   999 
  1000 * HOL/Arithmetic:
  1001   - `pred n' is automatically converted to `n-1'.
  1002     Users are strongly encouraged not to use `pred' any longer,
  1003     because it will disappear altogether at some point.
  1004   - Users are strongly encouraged to write "0 < n" rather than
  1005     "n ~= 0". Theorems and proof tools have been modified towards this
  1006     `standard'.
  1007 
  1008 * HOL/Lists:
  1009   the function "set_of_list" has been renamed "set" (and its theorems too);
  1010   the function "nth" now takes its arguments in the reverse order and
  1011   has acquired the infix notation "!" as in "xs!n".
  1012 
  1013 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1014 
  1015 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1016   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1017 
  1018 * HOL/record: extensible records with schematic structural subtyping
  1019 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1020 still lacks various theorems and concrete record syntax;
  1021 
  1022 
  1023 *** HOLCF ***
  1024 
  1025 * removed "axioms" and "generated by" sections;
  1026 
  1027 * replaced "ops" section by extended "consts" section, which is capable of
  1028   handling the continuous function space "->" directly;
  1029 
  1030 * domain package:
  1031   . proves theorems immediately and stores them in the theory,
  1032   . creates hierachical name space,
  1033   . now uses normal mixfix annotations (instead of cinfix...),
  1034   . minor changes to some names and values (for consistency),
  1035   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1036   . separator between mutual domain defs: changed "," to "and",
  1037   . improved handling of sort constraints;  now they have to
  1038     appear on the left-hand side of the equations only;
  1039 
  1040 * fixed LAM <x,y,zs>.b syntax;
  1041 
  1042 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1043 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1044 
  1045 
  1046 *** FOL and ZF ***
  1047 
  1048 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1049   with `addloop' of the simplifier to faciliate case splitting in premises.
  1050 
  1051 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1052 in HOL, they strip ALL and --> from proved theorems;
  1053 
  1054 
  1055 
  1056 New in Isabelle94-8 (May 1997)
  1057 ------------------------------
  1058 
  1059 *** General Changes ***
  1060 
  1061 * new utilities to build / run / maintain Isabelle etc. (in parts
  1062 still somewhat experimental); old Makefiles etc. still functional;
  1063 
  1064 * new 'Isabelle System Manual';
  1065 
  1066 * INSTALL text, together with ./configure and ./build scripts;
  1067 
  1068 * reimplemented type inference for greater efficiency, better error
  1069 messages and clean internal interface;
  1070 
  1071 * prlim command for dealing with lots of subgoals (an easier way of
  1072 setting goals_limit);
  1073 
  1074 
  1075 *** Syntax ***
  1076 
  1077 * supports alternative (named) syntax tables (parser and pretty
  1078 printer); internal interface is provided by add_modesyntax(_i);
  1079 
  1080 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1081 be used in conjunction with the Isabelle symbol font; uses the
  1082 "symbols" syntax table;
  1083 
  1084 * added token_translation interface (may translate name tokens in
  1085 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1086 the current print_mode); IMPORTANT: user print translation functions
  1087 are responsible for marking newly introduced bounds
  1088 (Syntax.mark_boundT);
  1089 
  1090 * token translations for modes "xterm" and "xterm_color" that display
  1091 names in bold, underline etc. or colors (which requires a color
  1092 version of xterm);
  1093 
  1094 * infixes may now be declared with names independent of their syntax;
  1095 
  1096 * added typed_print_translation (like print_translation, but may
  1097 access type of constant);
  1098 
  1099 
  1100 *** Classical Reasoner ***
  1101 
  1102 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1103 some limitations.  Blast_tac...
  1104   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1105   + ignores elimination rules that don't have the correct format
  1106         (the conclusion MUST be a formula variable)
  1107   + ignores types, which can make HOL proofs fail
  1108   + rules must not require higher-order unification, e.g. apply_type in ZF
  1109     [message "Function Var's argument not a bound variable" relates to this]
  1110   + its proof strategy is more general but can actually be slower
  1111 
  1112 * substitution with equality assumptions no longer permutes other
  1113 assumptions;
  1114 
  1115 * minor changes in semantics of addafter (now called addaltern); renamed
  1116 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1117 (and access functions for it);
  1118 
  1119 * improved combination of classical reasoner and simplifier:
  1120   + functions for handling clasimpsets
  1121   + improvement of addss: now the simplifier is called _after_ the
  1122     safe steps.
  1123   + safe variant of addss called addSss: uses safe simplifications
  1124     _during_ the safe steps. It is more complete as it allows multiple
  1125     instantiations of unknowns (e.g. with slow_tac).
  1126 
  1127 *** Simplifier ***
  1128 
  1129 * added interface for simplification procedures (functions that
  1130 produce *proven* rewrite rules on the fly, depending on current
  1131 redex);
  1132 
  1133 * ordering on terms as parameter (used for ordered rewriting);
  1134 
  1135 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1136 
  1137 * the solver is now split into a safe and an unsafe part.
  1138 This should be invisible for the normal user, except that the
  1139 functions setsolver and addsolver have been renamed to setSolver and
  1140 addSolver; added safe_asm_full_simp_tac;
  1141 
  1142 
  1143 *** HOL ***
  1144 
  1145 * a generic induction tactic `induct_tac' which works for all datatypes and
  1146 also for type `nat';
  1147 
  1148 * a generic case distinction tactic `exhaust_tac' which works for all
  1149 datatypes and also for type `nat';
  1150 
  1151 * each datatype comes with a function `size';
  1152 
  1153 * patterns in case expressions allow tuple patterns as arguments to
  1154 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1155 
  1156 * primrec now also works with type nat;
  1157 
  1158 * recdef: a new declaration form, allows general recursive functions to be
  1159 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1160 
  1161 * the constant for negation has been renamed from "not" to "Not" to
  1162 harmonize with FOL, ZF, LK, etc.;
  1163 
  1164 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1165 infinite lists;
  1166 
  1167 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1168 
  1169 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1170 problems in commutative rings, using axiomatic type classes for + and *;
  1171 
  1172 * more examples in HOL/MiniML and HOL/Auth;
  1173 
  1174 * more default rewrite rules for quantifiers, union/intersection;
  1175 
  1176 * a new constant `arbitrary == @x.False';
  1177 
  1178 * HOLCF/IOA replaces old HOL/IOA;
  1179 
  1180 * HOLCF changes: derived all rules and arities
  1181   + axiomatic type classes instead of classes
  1182   + typedef instead of faking type definitions
  1183   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1184   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1185   + eliminated the types void, one, tr
  1186   + use unit lift and bool lift (with translations) instead of one and tr
  1187   + eliminated blift from Lift3.thy (use Def instead of blift)
  1188   all eliminated rules are derived as theorems --> no visible changes ;
  1189 
  1190 
  1191 *** ZF ***
  1192 
  1193 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1194 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1195 as ZF_cs addSIs [equalityI];
  1196 
  1197 
  1198 
  1199 New in Isabelle94-7 (November 96)
  1200 ---------------------------------
  1201 
  1202 * allowing negative levels (as offsets) in prlev and choplev;
  1203 
  1204 * super-linear speedup for large simplifications;
  1205 
  1206 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1207 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1208 FAIL); can suppress it using the command Delsimps (ex_simps @
  1209 all_simps); De Morgan laws are also now included, by default;
  1210 
  1211 * improved printing of ==>  :  ~:
  1212 
  1213 * new object-logic "Sequents" adds linear logic, while replacing LK
  1214 and Modal (thanks to Sara Kalvala);
  1215 
  1216 * HOL/Auth: correctness proofs for authentication protocols;
  1217 
  1218 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1219 examples on HOL/Auth);
  1220 
  1221 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1222 the rewriter and classical reasoner simultaneously;
  1223 
  1224 * function uresult no longer returns theorems in "standard" format;
  1225 regain previous version by: val uresult = standard o uresult;
  1226 
  1227 
  1228 
  1229 New in Isabelle94-6
  1230 -------------------
  1231 
  1232 * oracles -- these establish an interface between Isabelle and trusted
  1233 external reasoners, which may deliver results as theorems;
  1234 
  1235 * proof objects (in particular record all uses of oracles);
  1236 
  1237 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1238 
  1239 * "constdefs" section in theory files;
  1240 
  1241 * "primrec" section (HOL) no longer requires names;
  1242 
  1243 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1244 
  1245 
  1246 
  1247 New in Isabelle94-5
  1248 -------------------
  1249 
  1250 * reduced space requirements;
  1251 
  1252 * automatic HTML generation from theories;
  1253 
  1254 * theory files no longer require "..." (quotes) around most types;
  1255 
  1256 * new examples, including two proofs of the Church-Rosser theorem;
  1257 
  1258 * non-curried (1994) version of HOL is no longer distributed;
  1259 
  1260 
  1261 
  1262 New in Isabelle94-4
  1263 -------------------
  1264 
  1265 * greatly reduced space requirements;
  1266 
  1267 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1268 
  1269 * searchable theorem database (see the section "Retrieving theorems" on
  1270 page 8 of the Reference Manual);
  1271 
  1272 * new examples, including Grabczewski's monumental case study of the
  1273 Axiom of Choice;
  1274 
  1275 * The previous version of HOL renamed to Old_HOL;
  1276 
  1277 * The new version of HOL (previously called CHOL) uses a curried syntax
  1278 for functions.  Application looks like f a b instead of f(a,b);
  1279 
  1280 * Mutually recursive inductive definitions finally work in HOL;
  1281 
  1282 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1283 translates to the operator "split";
  1284 
  1285 
  1286 
  1287 New in Isabelle94-3
  1288 -------------------
  1289 
  1290 * new infix operator, addss, allowing the classical reasoner to
  1291 perform simplification at each step of its search.  Example:
  1292         fast_tac (cs addss ss)
  1293 
  1294 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1295 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1296 look like (a,b) instead of <a,b>;
  1297 
  1298 * PLEASE NOTE: CHOL will eventually replace HOL!
  1299 
  1300 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1301 It translates to the operator "split".  A new theory of integers is available;
  1302 
  1303 * In ZF, integer numerals now denote two's-complement binary integers.
  1304 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1305 
  1306 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1307 of the Axiom of Choice;
  1308 
  1309 
  1310 
  1311 New in Isabelle94-2
  1312 -------------------
  1313 
  1314 * Significantly faster resolution;
  1315 
  1316 * the different sections in a .thy file can now be mixed and repeated
  1317 freely;
  1318 
  1319 * Database of theorems for FOL, HOL and ZF.  New
  1320 commands including qed, qed_goal and bind_thm store theorems in the database.
  1321 
  1322 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1323 a given theory (thms_of), or find out what theory a theorem was proved in
  1324 (theory_of_thm);
  1325 
  1326 * Bugs fixed in the inductive definition and datatype packages;
  1327 
  1328 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1329 and HOL_dup_cs obsolete;
  1330 
  1331 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1332 have been removed;
  1333 
  1334 * Simpler definition of function space in ZF;
  1335 
  1336 * new results about cardinal and ordinal arithmetic in ZF;
  1337 
  1338 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1339 types;
  1340 
  1341 
  1342 $Id$