NEWS
author wenzelm
Thu May 18 19:10:08 2000 +0200 (2000-05-18)
changeset 8887 c0c583ce0b0b
parent 8848 b06d183df34d
child 8921 7c04c98132c4
permissions -rw-r--r--
* HOL/ML: even fewer consts are declared as global (see theories Ord,
Lfp, Gfp, WF); this only affects ML packages that refer to const names
internally;
* 'pr' command: no longer prints theory contexts, but only proof
states;
     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
    11 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
    12 issue the following ML commands:
    13 
    14   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
    15   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
    16 
    17 * HOL: the constant for f``x is now "image" rather than "op ``";
    18 
    19 * HOL: the cartesian product is now "<*>" instead of "Times"; the
    20 lexicographic product is now "<*lex*>" instead of "**";
    21 
    22 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
    23 
    24 * HOL: simplification no longer dives into case-expressions
    25 
    26 * HOL: the recursion equations generated by 'recdef' are now called
    27 f.simps instead of f.rules;
    28 
    29 * HOL: theory Sexp now in HOL/Induct examples (used to be part of main
    30 HOL, but was unused); should better use HOL's datatype package anyway;
    31 
    32 * HOL/Real: "rabs" replaced by overloaded "abs" function;
    33 
    34 * HOL/ML: even fewer consts are declared as global (see theories Ord,
    35 Lfp, Gfp, WF); this only affects ML packages that refer to const names
    36 internally;
    37 
    38 * ML: PureThy.add_thms/add_axioms/add_defs return theorems as well;
    39 
    40 * LaTeX: several improvements of isabelle.sty;
    41 
    42 
    43 *** Document preparation ***
    44 
    45 * isatool mkdir provides easy setup of Isabelle session directories,
    46 including proper document sources;
    47 
    48 * generated LaTeX sources are now deleted after successful run
    49 (isatool document -c); may retain a copy somewhere else via -D option
    50 of isatool usedir;
    51 
    52 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
    53 style files, achieving self-contained LaTeX sources;
    54 
    55 * old-style theories now produce (crude) LaTeX output as well;
    56 
    57 
    58 *** Isar ***
    59 
    60 * Pure: local results and corresponding term bindings are now subject
    61 to Hindley-Milner polymorphism (similar to ML); this accommodates
    62 incremental type-inference nicely;
    63 
    64 * Pure: new 'obtain' language element supports generalized existence
    65 reasoning;
    66 
    67 * Pure: new calculational elements 'moreover' and 'ultimately' support
    68 plain accumulation of results, without applying any rules yet;
    69 
    70 * Pure: scalable support for case-analysis type proofs: new 'case'
    71 language element refers to local contexts symbolically, as produced by
    72 certain proof methods; internally, case names are attached to theorems
    73 as "tags";
    74 
    75 * Pure now provides its own version of intro/elim/dest attributes;
    76 useful for building new logics, but beware of confusion with the
    77 Provers/classical ones;
    78 
    79 * Provers: splitter support (via 'split' attribute and 'simp' method
    80 modifier); 'simp' method: 'only:' modifier removes loopers as well
    81 (including splits);
    82 
    83 * HOL: new proof method 'cases' and improved version of 'induct' now
    84 support named cases; major packages (inductive, datatype, primrec,
    85 recdef) support case names and properly name parameters;
    86 
    87 * HOL: removed 'case_split' thm binding, should use 'cases' proof
    88 method anyway;
    89 
    90 * names of theorems etc. may be natural numbers as well;
    91 
    92 * Provers: intro/elim/dest attributes: changed ! / !! flags to ? / ??;
    93 
    94 * 'pr' command: optional goals_limit argument; no longer prints theory
    95 contexts, but only proof states;
    96 
    97 * diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
    98 additional print modes to be specified; e.g. "pr(latex)" will print
    99 proof state according to the Isabelle LaTeX style;
   100 
   101 * improved support for emulating tactic scripts, including proof
   102 methods 'tactic', 'res_inst_tac' etc., 'subgoal_tac', and 'case_tac' /
   103 'induct_tac' (for HOL datatypes);
   104 
   105 * simplified (more robust) goal selection of proof methods: 1st goal,
   106 all goals, or explicit goal specifier (tactic emulation); thus 'proof
   107 method scripts' have to be in depth-first order;
   108 
   109 * tuned 'let' syntax: replace 'as' keyword by 'and';
   110 
   111 * theory command 'hide' removes declarations from class/type/const
   112 name spaces;
   113 
   114 
   115 *** HOL ***
   116 
   117 * HOL/Algebra: new theory of rings and univariate polynomials, by
   118 Clemens Ballarin;
   119 
   120 * HOL/record: fixed select-update simplification procedure to handle
   121 extended records as well; admit "r" as field name;
   122 
   123 * HOL/ex: new theory Factorization proving the Fundamental Theorem of
   124 Arithmetic, by Thomas M Rasmussen;
   125 
   126 * HOL/ex/Multiquote: multiple nested quotations and anti-quotations --
   127 basically a generalized version of de-Bruijn representation; very
   128 useful in avoiding lifting all operations;
   129 
   130 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   131 
   132 * greatly improved simplification involving numerals of type nat & int, e.g.
   133    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
   134    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
   135   two terms #m*u and #n*u are replaced by #(m+n)*u
   136     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   137   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   138     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   139 
   140 * HOL: new version of "case_tac" subsumes both boolean case split and
   141 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   142 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   143 
   144 * HOL: simplification no longer dives into case-expressions: only the
   145 selector expression is simplified, but not the remaining arms. To
   146 enable full simplification of case-expressions for datatype t, you
   147 need to remove t.weak_case_cong from the simpset, either permanently
   148 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   149 
   150 * HOL/recdef: the recursion equations generated by 'recdef' for
   151 function 'f' are now called f.simps instead of f.rules; if all
   152 termination conditions are proved automatically, these simplification
   153 rules are added to the simpset, as in primrec; rules may be named
   154 individually as well, resulting in a separate list of theorems for
   155 each equation;
   156 
   157 * HOL: theorems impI, allI, ballI bound as "strip";
   158 
   159 * theory Sexp now in HOL/Induct examples (used to be part of main HOL,
   160 but was unused);
   161 
   162 * fewer consts declared as global (e.g. have to refer to "Lfp.lfp"
   163 instead of "lfp" internally; affects ML packages only);
   164 
   165 
   166 *** General ***
   167 
   168 * improved name spaces: ambiguous output is qualified; support for
   169 hiding of names;
   170 
   171 * compression of ML heaps images may now be controlled via -c option
   172 of isabelle and isatool usedir (currently only observed by Poly/ML);
   173 
   174 * ML: new combinators |>> and |>>> for incremental transformations
   175 with secondary results (e.g. certain theory extensions):
   176 
   177 
   178 
   179 New in Isabelle99 (October 1999)
   180 --------------------------------
   181 
   182 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   183 
   184 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   185 are no longer simplified.  (This allows the simplifier to unfold recursive
   186 functional programs.)  To restore the old behaviour, declare
   187 
   188     Delcongs [if_weak_cong];
   189 
   190 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   191 complement;
   192 
   193 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   194 
   195 * HOL/datatype: mutual_induct_tac no longer exists --
   196   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   197 
   198 * HOL/typedef: fixed type inference for representing set; type
   199 arguments now have to occur explicitly on the rhs as type constraints;
   200 
   201 * ZF: The con_defs part of an inductive definition may no longer refer
   202 to constants declared in the same theory;
   203 
   204 * HOL, ZF: the function mk_cases, generated by the inductive
   205 definition package, has lost an argument.  To simplify its result, it
   206 uses the default simpset instead of a supplied list of theorems.
   207 
   208 * HOL/List: the constructors of type list are now Nil and Cons;
   209 
   210 * Simplifier: the type of the infix ML functions
   211         setSSolver addSSolver setSolver addSolver
   212 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   213 for packaging solvers. A solver is created via
   214         mk_solver: string -> (thm list -> int -> tactic) -> solver
   215 where the string argument is only a comment.
   216 
   217 
   218 *** Proof tools ***
   219 
   220 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   221 decision procedure for linear arithmetic. Currently it is used for
   222 types `nat', `int', and `real' in HOL (see below); it can, should and
   223 will be instantiated for other types and logics as well.
   224 
   225 * The simplifier now accepts rewrite rules with flexible heads, eg
   226      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   227   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   228   matching.
   229 
   230 
   231 *** General ***
   232 
   233 * New Isabelle/Isar subsystem provides an alternative to traditional
   234 tactical theorem proving; together with the ProofGeneral/isar user
   235 interface it offers an interactive environment for developing human
   236 readable proof documents (Isar == Intelligible semi-automated
   237 reasoning); for further information see isatool doc isar-ref,
   238 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   239 
   240 * improved presentation of theories: better HTML markup (including
   241 colors), graph views in several sizes; isatool usedir now provides a
   242 proper interface for user theories (via -P option); actual document
   243 preparation based on (PDF)LaTeX is available as well (for new-style
   244 theories only); see isatool doc system for more information;
   245 
   246 * native support for Proof General, both for classic Isabelle and
   247 Isabelle/Isar;
   248 
   249 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   250 using the graph browser tool;
   251 
   252 * Isabelle manuals now also available as PDF;
   253 
   254 * theory loader rewritten from scratch (may not be fully
   255 bug-compatible); old loadpath variable has been replaced by show_path,
   256 add_path, del_path, reset_path functions; new operations such as
   257 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   258 isatool doc ref);
   259 
   260 * improved isatool install: option -k creates KDE application icon,
   261 option -p DIR installs standalone binaries;
   262 
   263 * added ML_PLATFORM setting (useful for cross-platform installations);
   264 more robust handling of platform specific ML images for SML/NJ;
   265 
   266 * the settings environment is now statically scoped, i.e. it is never
   267 created again in sub-processes invoked from isabelle, isatool, or
   268 Isabelle;
   269 
   270 * path element specification '~~' refers to '$ISABELLE_HOME';
   271 
   272 * in locales, the "assumes" and "defines" parts may be omitted if
   273 empty;
   274 
   275 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   276 long arrows);
   277 
   278 * new print_mode "HTML";
   279 
   280 * new flag show_tags controls display of tags of theorems (which are
   281 basically just comments that may be attached by some tools);
   282 
   283 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   284 mode and goal output format:
   285 
   286 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   287 244c244
   288 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   289 ---
   290 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   291 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   292 181c181
   293 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   294 ---
   295 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   296 
   297 * function bind_thms stores lists of theorems (cf. bind_thm);
   298 
   299 * new shorthand tactics ftac, eatac, datac, fatac;
   300 
   301 * qed (and friends) now accept "" as result name; in that case the
   302 theorem is not stored, but proper checks and presentation of the
   303 result still apply;
   304 
   305 * theorem database now also indexes constants "Trueprop", "all",
   306 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   307 
   308 
   309 *** HOL ***
   310 
   311 ** HOL arithmetic **
   312 
   313 * There are now decision procedures for linear arithmetic over nat and
   314 int:
   315 
   316 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   317 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   318 are treated as atomic; subformulae not involving type `nat' or `int'
   319 are ignored; quantified subformulae are ignored unless they are
   320 positive universal or negative existential. The tactic has to be
   321 invoked by hand and can be a little bit slow. In particular, the
   322 running time is exponential in the number of occurrences of `min' and
   323 `max', and `-' on `nat'.
   324 
   325 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   326 (negated) (in)equalities among the premises and the conclusion into
   327 account (i.e. no compound formulae) and does not know about `min' and
   328 `max', and `-' on `nat'. It is fast and is used automatically by the
   329 simplifier.
   330 
   331 NB: At the moment, these decision procedures do not cope with mixed
   332 nat/int formulae where the two parts interact, such as `m < n ==>
   333 int(m) < int(n)'.
   334 
   335 * HOL/Numeral provides a generic theory of numerals (encoded
   336 efficiently as bit strings); setup for types nat/int/real is in place;
   337 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   338 int, existing theories and proof scripts may require a few additional
   339 type constraints;
   340 
   341 * integer division and remainder can now be performed on constant
   342 arguments;
   343 
   344 * many properties of integer multiplication, division and remainder
   345 are now available;
   346 
   347 * An interface to the Stanford Validity Checker (SVC) is available through the
   348 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   349 are proved automatically.  SVC must be installed separately, and its results
   350 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   351 invocation of the underlying oracle).  For SVC see
   352   http://verify.stanford.edu/SVC
   353 
   354 * IsaMakefile: the HOL-Real target now builds an actual image;
   355 
   356 
   357 ** HOL misc **
   358 
   359 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   360 (in Isabelle/Isar) -- by Gertrud Bauer;
   361 
   362 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   363 analysis for assembly languages with subtypes;
   364 
   365 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   366 -- avoids syntactic ambiguities and treats state, transition, and
   367 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   368 changed syntax and (many) tactics;
   369 
   370 * HOL/inductive: Now also handles more general introduction rules such
   371   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   372   theorems are now maintained within the theory (maintained via the
   373   "mono" attribute);
   374 
   375 * HOL/datatype: Now also handles arbitrarily branching datatypes
   376   (using function types) such as
   377 
   378   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   379 
   380 * HOL/record: record_simproc (part of the default simpset) takes care
   381 of selectors applied to updated records; record_split_tac is no longer
   382 part of the default claset; update_defs may now be removed from the
   383 simpset in many cases; COMPATIBILITY: old behavior achieved by
   384 
   385   claset_ref () := claset() addSWrapper record_split_wrapper;
   386   Delsimprocs [record_simproc]
   387 
   388 * HOL/typedef: fixed type inference for representing set; type
   389 arguments now have to occur explicitly on the rhs as type constraints;
   390 
   391 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   392 names rather than an ML expression;
   393 
   394 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   395 supplied later.  Program schemes can be defined, such as
   396     "While B C s = (if B s then While B C (C s) else s)"
   397 where the well-founded relation can be chosen after B and C have been given.
   398 
   399 * HOL/List: the constructors of type list are now Nil and Cons;
   400 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   401 course, ML tools referring to List.list.op # etc. have to be adapted;
   402 
   403 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   404 disabled by default; run isabelle with option -m HOL to get back to
   405 the original Gordon/HOL-style output;
   406 
   407 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   408 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   409 
   410 * HOL basic syntax simplified (more orthogonal): all variants of
   411 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   412 Eps operator is provided as well: "SOME x. P[x]";
   413 
   414 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   415 
   416 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   417 thus available for user theories;
   418 
   419 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   420 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   421 time;
   422 
   423 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   424 several times and then mp;
   425 
   426 
   427 *** LK ***
   428 
   429 * the notation <<...>> is now available as a notation for sequences of
   430 formulas;
   431 
   432 * the simplifier is now installed
   433 
   434 * the axiom system has been generalized (thanks to Soren Heilmann)
   435 
   436 * the classical reasoner now has a default rule database
   437 
   438 
   439 *** ZF ***
   440 
   441 * new primrec section allows primitive recursive functions to be given
   442 directly (as in HOL) over datatypes and the natural numbers;
   443 
   444 * new tactics induct_tac and exhaust_tac for induction (or case
   445 analysis) over datatypes and the natural numbers;
   446 
   447 * the datatype declaration of type T now defines the recursor T_rec;
   448 
   449 * simplification automatically does freeness reasoning for datatype
   450 constructors;
   451 
   452 * automatic type-inference, with AddTCs command to insert new
   453 type-checking rules;
   454 
   455 * datatype introduction rules are now added as Safe Introduction rules
   456 to the claset;
   457 
   458 * the syntax "if P then x else y" is now available in addition to
   459 if(P,x,y);
   460 
   461 
   462 *** Internal programming interfaces ***
   463 
   464 * tuned simplifier trace output; new flag debug_simp;
   465 
   466 * structures Vartab / Termtab (instances of TableFun) offer efficient
   467 tables indexed by indexname_ord / term_ord (compatible with aconv);
   468 
   469 * AxClass.axclass_tac lost the theory argument;
   470 
   471 * tuned current_goals_markers semantics: begin / end goal avoids
   472 printing empty lines;
   473 
   474 * removed prs and prs_fn hook, which was broken because it did not
   475 include \n in its semantics, forcing writeln to add one
   476 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   477 string -> unit if you really want to output text without newline;
   478 
   479 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   480 plain output, interface builders may have to enable 'isabelle_font'
   481 mode to get Isabelle font glyphs as before;
   482 
   483 * refined token_translation interface; INCOMPATIBILITY: output length
   484 now of type real instead of int;
   485 
   486 * theory loader actions may be traced via new ThyInfo.add_hook
   487 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   488 your own database of information attached to *whole* theories -- as
   489 opposed to intra-theory data slots offered via TheoryDataFun;
   490 
   491 * proper handling of dangling sort hypotheses (at last!);
   492 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   493 extra sort hypotheses that can be witnessed from the type signature;
   494 the force_strip_shyps flag is gone, any remaining shyps are simply
   495 left in the theorem (with a warning issued by strip_shyps_warning);
   496 
   497 
   498 
   499 New in Isabelle98-1 (October 1998)
   500 ----------------------------------
   501 
   502 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   503 
   504 * several changes of automated proof tools;
   505 
   506 * HOL: major changes to the inductive and datatype packages, including
   507 some minor incompatibilities of theory syntax;
   508 
   509 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   510 called `inj_on';
   511 
   512 * HOL: removed duplicate thms in Arith:
   513   less_imp_add_less  should be replaced by  trans_less_add1
   514   le_imp_add_le      should be replaced by  trans_le_add1
   515 
   516 * HOL: unary minus is now overloaded (new type constraints may be
   517 required);
   518 
   519 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   520 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   521 now taken as an integer constant.
   522 
   523 * Pure: ML function 'theory_of' renamed to 'theory';
   524 
   525 
   526 *** Proof tools ***
   527 
   528 * Simplifier:
   529   1. Asm_full_simp_tac is now more aggressive.
   530      1. It will sometimes reorient premises if that increases their power to
   531         simplify.
   532      2. It does no longer proceed strictly from left to right but may also
   533         rotate premises to achieve further simplification.
   534      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   535      old Asm_full_simp_tac in that it does not rotate premises.
   536   2. The simplifier now knows a little bit about nat-arithmetic.
   537 
   538 * Classical reasoner: wrapper mechanism for the classical reasoner now
   539 allows for selected deletion of wrappers, by introduction of names for
   540 wrapper functionals.  This implies that addbefore, addSbefore,
   541 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   542 and that adding two tactics with the same name overwrites the first
   543 one (emitting a warning).
   544   type wrapper = (int -> tactic) -> (int -> tactic)
   545   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   546   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   547   delWrapper, delSWrapper: claset *  string            -> claset
   548   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   549 
   550 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   551 semantics; addbefore now affects only the unsafe part of step_tac
   552 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   553 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   554 by Force_tac;
   555 
   556 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   557 compWrapper; added safe wrapper (and access functions for it);
   558 
   559 * HOL/split_all_tac is now much faster and fails if there is nothing
   560 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   561 and the names of the automatically generated variables have changed.
   562 split_all_tac has moved within claset() from unsafe wrappers to safe
   563 wrappers, which means that !!-bound variables are split much more
   564 aggressively, and safe_tac and clarify_tac now split such variables.
   565 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   566 Note: the same holds for record_split_tac, which does the job of
   567 split_all_tac for record fields.
   568 
   569 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   570 permanently to the default simpset using Addsplits just like
   571 Addsimps. They can be removed via Delsplits just like
   572 Delsimps. Lower-case versions are also available.
   573 
   574 * HOL/Simplifier: The rule split_if is now part of the default
   575 simpset. This means that the simplifier will eliminate all occurrences
   576 of if-then-else in the conclusion of a goal. To prevent this, you can
   577 either remove split_if completely from the default simpset by
   578 `Delsplits [split_if]' or remove it in a specific call of the
   579 simplifier using `... delsplits [split_if]'.  You can also add/delete
   580 other case splitting rules to/from the default simpset: every datatype
   581 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   582 t is the name of the datatype).
   583 
   584 * Classical reasoner / Simplifier combination: new force_tac (and
   585 derivatives Force_tac, force) combines rewriting and classical
   586 reasoning (and whatever other tools) similarly to auto_tac, but is
   587 aimed to solve the given subgoal completely.
   588 
   589 
   590 *** General ***
   591 
   592 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   593 and `goalw': the theory is no longer needed as an explicit argument -
   594 the current theory context is used; assumptions are no longer returned
   595 at the ML-level unless one of them starts with ==> or !!; it is
   596 recommended to convert to these new commands using isatool fixgoal
   597 (backup your sources first!);
   598 
   599 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   600 the current theory context, and 'theory' to lookup stored theories;
   601 
   602 * new theory section 'locale' for declaring constants, assumptions and
   603 definitions that have local scope;
   604 
   605 * new theory section 'nonterminals' for purely syntactic types;
   606 
   607 * new theory section 'setup' for generic ML setup functions
   608 (e.g. package initialization);
   609 
   610 * the distribution now includes Isabelle icons: see
   611 lib/logo/isabelle-{small,tiny}.xpm;
   612 
   613 * isatool install - install binaries with absolute references to
   614 ISABELLE_HOME/bin;
   615 
   616 * isatool logo -- create instances of the Isabelle logo (as EPS);
   617 
   618 * print mode 'emacs' reserved for Isamode;
   619 
   620 * support multiple print (ast) translations per constant name;
   621 
   622 * theorems involving oracles are now printed with a suffixed [!];
   623 
   624 
   625 *** HOL ***
   626 
   627 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   628 
   629 * HOL/inductive package reorganized and improved: now supports mutual
   630 definitions such as
   631 
   632   inductive EVEN ODD
   633     intrs
   634       null "0 : EVEN"
   635       oddI "n : EVEN ==> Suc n : ODD"
   636       evenI "n : ODD ==> Suc n : EVEN"
   637 
   638 new theorem list "elims" contains an elimination rule for each of the
   639 recursive sets; inductive definitions now handle disjunctive premises
   640 correctly (also ZF);
   641 
   642 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   643 "mutual_induct" no longer exists - the induction rule is always
   644 contained in "induct";
   645 
   646 
   647 * HOL/datatype package re-implemented and greatly improved: now
   648 supports mutually recursive datatypes such as
   649 
   650   datatype
   651     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   652             | SUM ('a aexp) ('a aexp)
   653             | DIFF ('a aexp) ('a aexp)
   654             | NUM 'a
   655   and
   656     'a bexp = LESS ('a aexp) ('a aexp)
   657             | AND ('a bexp) ('a bexp)
   658             | OR ('a bexp) ('a bexp)
   659 
   660 as well as indirectly recursive datatypes such as
   661 
   662   datatype
   663     ('a, 'b) term = Var 'a
   664                   | App 'b ((('a, 'b) term) list)
   665 
   666 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   667 induction on mutually / indirectly recursive datatypes.
   668 
   669 Primrec equations are now stored in theory and can be accessed via
   670 <function_name>.simps.
   671 
   672 INCOMPATIBILITIES:
   673 
   674   - Theories using datatypes must now have theory Datatype as an
   675     ancestor.
   676   - The specific <typename>.induct_tac no longer exists - use the
   677     generic induct_tac instead.
   678   - natE has been renamed to nat.exhaust - use exhaust_tac
   679     instead of res_inst_tac ... natE. Note that the variable
   680     names in nat.exhaust differ from the names in natE, this
   681     may cause some "fragile" proofs to fail.
   682   - The theorems split_<typename>_case and split_<typename>_case_asm
   683     have been renamed to <typename>.split and <typename>.split_asm.
   684   - Since default sorts of type variables are now handled correctly,
   685     some datatype definitions may have to be annotated with explicit
   686     sort constraints.
   687   - Primrec definitions no longer require function name and type
   688     of recursive argument.
   689 
   690 Consider using isatool fixdatatype to adapt your theories and proof
   691 scripts to the new package (backup your sources first!).
   692 
   693 
   694 * HOL/record package: considerably improved implementation; now
   695 includes concrete syntax for record types, terms, updates; theorems
   696 for surjective pairing and splitting !!-bound record variables; proof
   697 support is as follows:
   698 
   699   1) standard conversions (selectors or updates applied to record
   700 constructor terms) are part of the standard simpset;
   701 
   702   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   703 made part of standard simpset and claset via addIffs;
   704 
   705   3) a tactic for record field splitting (record_split_tac) is part of
   706 the standard claset (addSWrapper);
   707 
   708 To get a better idea about these rules you may retrieve them via
   709 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   710 the name of your record type.
   711 
   712 The split tactic 3) conceptually simplifies by the following rule:
   713 
   714   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   715 
   716 Thus any record variable that is bound by meta-all will automatically
   717 blow up into some record constructor term, consequently the
   718 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   719 solve record problems automatically.
   720 
   721 
   722 * reorganized the main HOL image: HOL/Integ and String loaded by
   723 default; theory Main includes everything;
   724 
   725 * automatic simplification of integer sums and comparisons, using cancellation;
   726 
   727 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   728 
   729 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   730 
   731 * many new identities for unions, intersections, set difference, etc.;
   732 
   733 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   734 called split_if, split_split, split_sum_case and split_nat_case (to go
   735 with add/delsplits);
   736 
   737 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   738 (?x::unit) = (); this is made part of the default simpset, which COULD
   739 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   740 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   741 unit_abs_eta_conv is added in order to counter the effect of
   742 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   743 %u.f();
   744 
   745 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   746 makes more sense);
   747 
   748 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   749   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   750   disjointness reasoning but breaking a few old proofs.
   751 
   752 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   753 to 'converse' from 'inverse' (for compatibility with ZF and some
   754 literature);
   755 
   756 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   757 the well-founded relation;
   758 
   759 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   760     Compl A.  The "Compl" syntax remains available as input syntax for this
   761     release ONLY.
   762 
   763 * HOL/Update: new theory of function updates:
   764     f(a:=b) == %x. if x=a then b else f x
   765 may also be iterated as in f(a:=b,c:=d,...);
   766 
   767 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   768 
   769 * HOL/List:
   770   - new function list_update written xs[i:=v] that updates the i-th
   771     list position. May also be iterated as in xs[i:=a,j:=b,...].
   772   - new function `upt' written [i..j(] which generates the list
   773     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   774     bound write [i..j], which is a shorthand for [i..j+1(].
   775   - new lexicographic orderings and corresponding wellfoundedness theorems.
   776 
   777 * HOL/Arith:
   778   - removed 'pred' (predecessor) function;
   779   - generalized some theorems about n-1;
   780   - many new laws about "div" and "mod";
   781   - new laws about greatest common divisors (see theory ex/Primes);
   782 
   783 * HOL/Relation: renamed the relational operator r^-1 "converse"
   784 instead of "inverse";
   785 
   786 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   787   of the multiset ordering;
   788 
   789 * directory HOL/Real: a construction of the reals using Dedekind cuts
   790   (not included by default);
   791 
   792 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   793 
   794 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   795   programs, i.e. different program variables may have different types.
   796 
   797 * calling (stac rew i) now fails if "rew" has no effect on the goal
   798   [previously, this check worked only if the rewrite rule was unconditional]
   799   Now rew can involve either definitions or equalities (either == or =).
   800 
   801 
   802 *** ZF ***
   803 
   804 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   805   only the theorems proved on ZF.ML;
   806 
   807 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   808   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   809   disjointness reasoning but breaking a few old proofs.
   810 
   811 * ZF/Update: new theory of function updates
   812     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   813   may also be iterated as in f(a:=b,c:=d,...);
   814 
   815 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   816 
   817 * calling (stac rew i) now fails if "rew" has no effect on the goal
   818   [previously, this check worked only if the rewrite rule was unconditional]
   819   Now rew can involve either definitions or equalities (either == or =).
   820 
   821 * case_tac provided for compatibility with HOL
   822     (like the old excluded_middle_tac, but with subgoals swapped)
   823 
   824 
   825 *** Internal programming interfaces ***
   826 
   827 * Pure: several new basic modules made available for general use, see
   828 also src/Pure/README;
   829 
   830 * improved the theory data mechanism to support encapsulation (data
   831 kind name replaced by private Object.kind, acting as authorization
   832 key); new type-safe user interface via functor TheoryDataFun; generic
   833 print_data function becomes basically useless;
   834 
   835 * removed global_names compatibility flag -- all theory declarations
   836 are qualified by default;
   837 
   838 * module Pure/Syntax now offers quote / antiquote translation
   839 functions (useful for Hoare logic etc. with implicit dependencies);
   840 see HOL/ex/Antiquote for an example use;
   841 
   842 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   843 cterm -> thm;
   844 
   845 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   846 subgoal;
   847 
   848 * Display.print_goals function moved to Locale.print_goals;
   849 
   850 * standard print function for goals supports current_goals_markers
   851 variable for marking begin of proof, end of proof, start of goal; the
   852 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   853 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   854 for example;
   855 
   856 
   857 
   858 New in Isabelle98 (January 1998)
   859 --------------------------------
   860 
   861 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   862 
   863 * changed lexical syntax of terms / types: dots made part of long
   864 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   865 
   866 * simpset (and claset) reference variable replaced by functions
   867 simpset / simpset_ref;
   868 
   869 * no longer supports theory aliases (via merge) and non-trivial
   870 implicit merge of thms' signatures;
   871 
   872 * most internal names of constants changed due to qualified names;
   873 
   874 * changed Pure/Sequence interface (see Pure/seq.ML);
   875 
   876 
   877 *** General Changes ***
   878 
   879 * hierachically structured name spaces (for consts, types, axms, thms
   880 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   881 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   882 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   883 long_names for fully qualified output names; NOTE: ML programs
   884 (special tactics, packages etc.) referring to internal names may have
   885 to be adapted to cope with fully qualified names; in case of severe
   886 backward campatibility problems try setting 'global_names' at compile
   887 time to have enrything declared within a flat name space; one may also
   888 fine tune name declarations in theories via the 'global' and 'local'
   889 section;
   890 
   891 * reimplemented the implicit simpset and claset using the new anytype
   892 data filed in signatures; references simpset:simpset ref etc. are
   893 replaced by functions simpset:unit->simpset and
   894 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   895 to patch your ML files accordingly;
   896 
   897 * HTML output now includes theory graph data for display with Java
   898 applet or isatool browser; data generated automatically via isatool
   899 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   900 
   901 * defs may now be conditional; improved rewrite_goals_tac to handle
   902 conditional equations;
   903 
   904 * defs now admits additional type arguments, using TYPE('a) syntax;
   905 
   906 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   907 creates a new theory node; implicit merge of thms' signatures is
   908 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   909 transfer:theory->thm->thm in (rare) cases;
   910 
   911 * improved handling of draft signatures / theories; draft thms (and
   912 ctyps, cterms) are automatically promoted to real ones;
   913 
   914 * slightly changed interfaces for oracles: admit many per theory, named
   915 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   916 
   917 * print_goals: optional output of const types (set show_consts and
   918 show_types);
   919 
   920 * improved output of warnings (###) and errors (***);
   921 
   922 * subgoal_tac displays a warning if the new subgoal has type variables;
   923 
   924 * removed old README and Makefiles;
   925 
   926 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   927 
   928 * removed obsolete init_pps and init_database;
   929 
   930 * deleted the obsolete tactical STATE, which was declared by
   931     fun STATE tacfun st = tacfun st st;
   932 
   933 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   934 (which abbreviates $HOME);
   935 
   936 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   937 use isatool fixseq to adapt your ML programs (this works for fully
   938 qualified references to the Sequence structure only!);
   939 
   940 * use_thy no longer requires writable current directory; it always
   941 reloads .ML *and* .thy file, if either one is out of date;
   942 
   943 
   944 *** Classical Reasoner ***
   945 
   946 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   947 tactics that use classical reasoning to simplify a subgoal without
   948 splitting it into several subgoals;
   949 
   950 * Safe_tac: like safe_tac but uses the default claset;
   951 
   952 
   953 *** Simplifier ***
   954 
   955 * added simplification meta rules:
   956     (asm_)(full_)simplify: simpset -> thm -> thm;
   957 
   958 * simplifier.ML no longer part of Pure -- has to be loaded by object
   959 logics (again);
   960 
   961 * added prems argument to simplification procedures;
   962 
   963 * HOL, FOL, ZF: added infix function `addsplits':
   964   instead of `<simpset> setloop (split_tac <thms>)'
   965   you can simply write `<simpset> addsplits <thms>'
   966 
   967 
   968 *** Syntax ***
   969 
   970 * TYPE('a) syntax for type reflection terms;
   971 
   972 * no longer handles consts with name "" -- declare as 'syntax' instead;
   973 
   974 * pretty printer: changed order of mixfix annotation preference (again!);
   975 
   976 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   977 
   978 
   979 *** HOL ***
   980 
   981 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   982   with `addloop' of the simplifier to faciliate case splitting in premises.
   983 
   984 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   985 
   986 * HOL/Auth: new protocol proofs including some for the Internet
   987   protocol TLS;
   988 
   989 * HOL/Map: new theory of `maps' a la VDM;
   990 
   991 * HOL/simplifier: simplification procedures nat_cancel_sums for
   992 cancelling out common nat summands from =, <, <= (in)equalities, or
   993 differences; simplification procedures nat_cancel_factor for
   994 cancelling common factor from =, <, <= (in)equalities over natural
   995 sums; nat_cancel contains both kinds of procedures, it is installed by
   996 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   997 
   998 * HOL/simplifier: terms of the form
   999   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  1000   are rewritten to
  1001   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  1002   and those of the form
  1003   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  1004   are rewritten to
  1005   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  1006 
  1007 * HOL/datatype
  1008   Each datatype `t' now comes with a theorem `split_t_case' of the form
  1009 
  1010   P(t_case f1 ... fn x) =
  1011      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  1012         ...
  1013        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  1014      )
  1015 
  1016   and a theorem `split_t_case_asm' of the form
  1017 
  1018   P(t_case f1 ... fn x) =
  1019     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  1020         ...
  1021        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  1022      )
  1023   which can be added to a simpset via `addsplits'. The existing theorems
  1024   expand_list_case and expand_option_case have been renamed to
  1025   split_list_case and split_option_case.
  1026 
  1027 * HOL/Arithmetic:
  1028   - `pred n' is automatically converted to `n-1'.
  1029     Users are strongly encouraged not to use `pred' any longer,
  1030     because it will disappear altogether at some point.
  1031   - Users are strongly encouraged to write "0 < n" rather than
  1032     "n ~= 0". Theorems and proof tools have been modified towards this
  1033     `standard'.
  1034 
  1035 * HOL/Lists:
  1036   the function "set_of_list" has been renamed "set" (and its theorems too);
  1037   the function "nth" now takes its arguments in the reverse order and
  1038   has acquired the infix notation "!" as in "xs!n".
  1039 
  1040 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1041 
  1042 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1043   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1044 
  1045 * HOL/record: extensible records with schematic structural subtyping
  1046 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1047 still lacks various theorems and concrete record syntax;
  1048 
  1049 
  1050 *** HOLCF ***
  1051 
  1052 * removed "axioms" and "generated by" sections;
  1053 
  1054 * replaced "ops" section by extended "consts" section, which is capable of
  1055   handling the continuous function space "->" directly;
  1056 
  1057 * domain package:
  1058   . proves theorems immediately and stores them in the theory,
  1059   . creates hierachical name space,
  1060   . now uses normal mixfix annotations (instead of cinfix...),
  1061   . minor changes to some names and values (for consistency),
  1062   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1063   . separator between mutual domain defs: changed "," to "and",
  1064   . improved handling of sort constraints;  now they have to
  1065     appear on the left-hand side of the equations only;
  1066 
  1067 * fixed LAM <x,y,zs>.b syntax;
  1068 
  1069 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1070 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1071 
  1072 
  1073 *** FOL and ZF ***
  1074 
  1075 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1076   with `addloop' of the simplifier to faciliate case splitting in premises.
  1077 
  1078 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1079 in HOL, they strip ALL and --> from proved theorems;
  1080 
  1081 
  1082 
  1083 New in Isabelle94-8 (May 1997)
  1084 ------------------------------
  1085 
  1086 *** General Changes ***
  1087 
  1088 * new utilities to build / run / maintain Isabelle etc. (in parts
  1089 still somewhat experimental); old Makefiles etc. still functional;
  1090 
  1091 * new 'Isabelle System Manual';
  1092 
  1093 * INSTALL text, together with ./configure and ./build scripts;
  1094 
  1095 * reimplemented type inference for greater efficiency, better error
  1096 messages and clean internal interface;
  1097 
  1098 * prlim command for dealing with lots of subgoals (an easier way of
  1099 setting goals_limit);
  1100 
  1101 
  1102 *** Syntax ***
  1103 
  1104 * supports alternative (named) syntax tables (parser and pretty
  1105 printer); internal interface is provided by add_modesyntax(_i);
  1106 
  1107 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1108 be used in conjunction with the Isabelle symbol font; uses the
  1109 "symbols" syntax table;
  1110 
  1111 * added token_translation interface (may translate name tokens in
  1112 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1113 the current print_mode); IMPORTANT: user print translation functions
  1114 are responsible for marking newly introduced bounds
  1115 (Syntax.mark_boundT);
  1116 
  1117 * token translations for modes "xterm" and "xterm_color" that display
  1118 names in bold, underline etc. or colors (which requires a color
  1119 version of xterm);
  1120 
  1121 * infixes may now be declared with names independent of their syntax;
  1122 
  1123 * added typed_print_translation (like print_translation, but may
  1124 access type of constant);
  1125 
  1126 
  1127 *** Classical Reasoner ***
  1128 
  1129 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1130 some limitations.  Blast_tac...
  1131   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1132   + ignores elimination rules that don't have the correct format
  1133         (the conclusion MUST be a formula variable)
  1134   + ignores types, which can make HOL proofs fail
  1135   + rules must not require higher-order unification, e.g. apply_type in ZF
  1136     [message "Function Var's argument not a bound variable" relates to this]
  1137   + its proof strategy is more general but can actually be slower
  1138 
  1139 * substitution with equality assumptions no longer permutes other
  1140 assumptions;
  1141 
  1142 * minor changes in semantics of addafter (now called addaltern); renamed
  1143 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1144 (and access functions for it);
  1145 
  1146 * improved combination of classical reasoner and simplifier:
  1147   + functions for handling clasimpsets
  1148   + improvement of addss: now the simplifier is called _after_ the
  1149     safe steps.
  1150   + safe variant of addss called addSss: uses safe simplifications
  1151     _during_ the safe steps. It is more complete as it allows multiple
  1152     instantiations of unknowns (e.g. with slow_tac).
  1153 
  1154 *** Simplifier ***
  1155 
  1156 * added interface for simplification procedures (functions that
  1157 produce *proven* rewrite rules on the fly, depending on current
  1158 redex);
  1159 
  1160 * ordering on terms as parameter (used for ordered rewriting);
  1161 
  1162 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1163 
  1164 * the solver is now split into a safe and an unsafe part.
  1165 This should be invisible for the normal user, except that the
  1166 functions setsolver and addsolver have been renamed to setSolver and
  1167 addSolver; added safe_asm_full_simp_tac;
  1168 
  1169 
  1170 *** HOL ***
  1171 
  1172 * a generic induction tactic `induct_tac' which works for all datatypes and
  1173 also for type `nat';
  1174 
  1175 * a generic case distinction tactic `exhaust_tac' which works for all
  1176 datatypes and also for type `nat';
  1177 
  1178 * each datatype comes with a function `size';
  1179 
  1180 * patterns in case expressions allow tuple patterns as arguments to
  1181 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1182 
  1183 * primrec now also works with type nat;
  1184 
  1185 * recdef: a new declaration form, allows general recursive functions to be
  1186 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1187 
  1188 * the constant for negation has been renamed from "not" to "Not" to
  1189 harmonize with FOL, ZF, LK, etc.;
  1190 
  1191 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1192 infinite lists;
  1193 
  1194 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1195 
  1196 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1197 problems in commutative rings, using axiomatic type classes for + and *;
  1198 
  1199 * more examples in HOL/MiniML and HOL/Auth;
  1200 
  1201 * more default rewrite rules for quantifiers, union/intersection;
  1202 
  1203 * a new constant `arbitrary == @x.False';
  1204 
  1205 * HOLCF/IOA replaces old HOL/IOA;
  1206 
  1207 * HOLCF changes: derived all rules and arities
  1208   + axiomatic type classes instead of classes
  1209   + typedef instead of faking type definitions
  1210   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1211   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1212   + eliminated the types void, one, tr
  1213   + use unit lift and bool lift (with translations) instead of one and tr
  1214   + eliminated blift from Lift3.thy (use Def instead of blift)
  1215   all eliminated rules are derived as theorems --> no visible changes ;
  1216 
  1217 
  1218 *** ZF ***
  1219 
  1220 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1221 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1222 as ZF_cs addSIs [equalityI];
  1223 
  1224 
  1225 
  1226 New in Isabelle94-7 (November 96)
  1227 ---------------------------------
  1228 
  1229 * allowing negative levels (as offsets) in prlev and choplev;
  1230 
  1231 * super-linear speedup for large simplifications;
  1232 
  1233 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1234 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1235 FAIL); can suppress it using the command Delsimps (ex_simps @
  1236 all_simps); De Morgan laws are also now included, by default;
  1237 
  1238 * improved printing of ==>  :  ~:
  1239 
  1240 * new object-logic "Sequents" adds linear logic, while replacing LK
  1241 and Modal (thanks to Sara Kalvala);
  1242 
  1243 * HOL/Auth: correctness proofs for authentication protocols;
  1244 
  1245 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1246 examples on HOL/Auth);
  1247 
  1248 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1249 the rewriter and classical reasoner simultaneously;
  1250 
  1251 * function uresult no longer returns theorems in "standard" format;
  1252 regain previous version by: val uresult = standard o uresult;
  1253 
  1254 
  1255 
  1256 New in Isabelle94-6
  1257 -------------------
  1258 
  1259 * oracles -- these establish an interface between Isabelle and trusted
  1260 external reasoners, which may deliver results as theorems;
  1261 
  1262 * proof objects (in particular record all uses of oracles);
  1263 
  1264 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1265 
  1266 * "constdefs" section in theory files;
  1267 
  1268 * "primrec" section (HOL) no longer requires names;
  1269 
  1270 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1271 
  1272 
  1273 
  1274 New in Isabelle94-5
  1275 -------------------
  1276 
  1277 * reduced space requirements;
  1278 
  1279 * automatic HTML generation from theories;
  1280 
  1281 * theory files no longer require "..." (quotes) around most types;
  1282 
  1283 * new examples, including two proofs of the Church-Rosser theorem;
  1284 
  1285 * non-curried (1994) version of HOL is no longer distributed;
  1286 
  1287 
  1288 
  1289 New in Isabelle94-4
  1290 -------------------
  1291 
  1292 * greatly reduced space requirements;
  1293 
  1294 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1295 
  1296 * searchable theorem database (see the section "Retrieving theorems" on
  1297 page 8 of the Reference Manual);
  1298 
  1299 * new examples, including Grabczewski's monumental case study of the
  1300 Axiom of Choice;
  1301 
  1302 * The previous version of HOL renamed to Old_HOL;
  1303 
  1304 * The new version of HOL (previously called CHOL) uses a curried syntax
  1305 for functions.  Application looks like f a b instead of f(a,b);
  1306 
  1307 * Mutually recursive inductive definitions finally work in HOL;
  1308 
  1309 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1310 translates to the operator "split";
  1311 
  1312 
  1313 
  1314 New in Isabelle94-3
  1315 -------------------
  1316 
  1317 * new infix operator, addss, allowing the classical reasoner to
  1318 perform simplification at each step of its search.  Example:
  1319         fast_tac (cs addss ss)
  1320 
  1321 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1322 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1323 look like (a,b) instead of <a,b>;
  1324 
  1325 * PLEASE NOTE: CHOL will eventually replace HOL!
  1326 
  1327 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1328 It translates to the operator "split".  A new theory of integers is available;
  1329 
  1330 * In ZF, integer numerals now denote two's-complement binary integers.
  1331 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1332 
  1333 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1334 of the Axiom of Choice;
  1335 
  1336 
  1337 
  1338 New in Isabelle94-2
  1339 -------------------
  1340 
  1341 * Significantly faster resolution;
  1342 
  1343 * the different sections in a .thy file can now be mixed and repeated
  1344 freely;
  1345 
  1346 * Database of theorems for FOL, HOL and ZF.  New
  1347 commands including qed, qed_goal and bind_thm store theorems in the database.
  1348 
  1349 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1350 a given theory (thms_of), or find out what theory a theorem was proved in
  1351 (theory_of_thm);
  1352 
  1353 * Bugs fixed in the inductive definition and datatype packages;
  1354 
  1355 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1356 and HOL_dup_cs obsolete;
  1357 
  1358 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1359 have been removed;
  1360 
  1361 * Simpler definition of function space in ZF;
  1362 
  1363 * new results about cardinal and ordinal arithmetic in ZF;
  1364 
  1365 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1366 types;
  1367 
  1368 
  1369 $Id$