NEWS
author paulson
Mon May 08 16:57:53 2000 +0200 (2000-05-08)
changeset 8832 bcceda950cd0
parent 8788 518a5450ab6d
child 8848 b06d183df34d
permissions -rw-r--r--
more details
     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    20 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;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 & int, 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   two terms #m*u and #n*u are replaced by #(m+n)*u
   122     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
   123   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
   124     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
   125 
   126 * new version of "case_tac" subsumes both boolean case split and
   127 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
   128 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
   129 
   130 * simplification no longer dives into case-expressions: only the selector
   131 expression is simplified, but not the remaining arms. To enable full
   132 simplification of case-expressions for datatype t, you need to remove
   133 t.weak_case_cong from the simpset, either permanently
   134 (Delcongs[thm"t.weak_case_cong"];) or locally (delcongs [...]).
   135 
   136 * the recursion equations generated by 'recdef' for function 'f' are
   137 now called f.simps instead of f.rules; if all termination conditions
   138 are proved automatically, these simplification rules are added to the
   139 simpset, as in primrec; rules may be named individually as well,
   140 resulting in a separate list of theorems for each equation;
   141 
   142 
   143 *** General ***
   144 
   145 * improved name spaces: ambiguous output is qualified; support for
   146 hiding of names;
   147 
   148 * compression of ML heaps images may now be controlled via -c option
   149 of isabelle and isatool usedir (currently only observed by Poly/ML);
   150 
   151 * ML: new combinators |>> and |>>> for incremental transformations
   152 with secondary results (e.g. certain theory extensions):
   153 
   154 
   155 
   156 New in Isabelle99 (October 1999)
   157 --------------------------------
   158 
   159 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   160 
   161 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
   162 are no longer simplified.  (This allows the simplifier to unfold recursive
   163 functional programs.)  To restore the old behaviour, declare
   164 
   165     Delcongs [if_weak_cong];
   166 
   167 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
   168 complement;
   169 
   170 * HOL: the predicate "inj" is now defined by translation to "inj_on";
   171 
   172 * HOL/datatype: mutual_induct_tac no longer exists --
   173   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
   174 
   175 * HOL/typedef: fixed type inference for representing set; type
   176 arguments now have to occur explicitly on the rhs as type constraints;
   177 
   178 * ZF: The con_defs part of an inductive definition may no longer refer
   179 to constants declared in the same theory;
   180 
   181 * HOL, ZF: the function mk_cases, generated by the inductive
   182 definition package, has lost an argument.  To simplify its result, it
   183 uses the default simpset instead of a supplied list of theorems.
   184 
   185 * HOL/List: the constructors of type list are now Nil and Cons;
   186 
   187 * Simplifier: the type of the infix ML functions
   188         setSSolver addSSolver setSolver addSolver
   189 is now  simpset * solver -> simpset  where `solver' is a new abstract type
   190 for packaging solvers. A solver is created via
   191         mk_solver: string -> (thm list -> int -> tactic) -> solver
   192 where the string argument is only a comment.
   193 
   194 
   195 *** Proof tools ***
   196 
   197 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
   198 decision procedure for linear arithmetic. Currently it is used for
   199 types `nat', `int', and `real' in HOL (see below); it can, should and
   200 will be instantiated for other types and logics as well.
   201 
   202 * The simplifier now accepts rewrite rules with flexible heads, eg
   203      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
   204   They are applied like any rule with a non-pattern lhs, i.e. by first-order
   205   matching.
   206 
   207 
   208 *** General ***
   209 
   210 * New Isabelle/Isar subsystem provides an alternative to traditional
   211 tactical theorem proving; together with the ProofGeneral/isar user
   212 interface it offers an interactive environment for developing human
   213 readable proof documents (Isar == Intelligible semi-automated
   214 reasoning); for further information see isatool doc isar-ref,
   215 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
   216 
   217 * improved presentation of theories: better HTML markup (including
   218 colors), graph views in several sizes; isatool usedir now provides a
   219 proper interface for user theories (via -P option); actual document
   220 preparation based on (PDF)LaTeX is available as well (for new-style
   221 theories only); see isatool doc system for more information;
   222 
   223 * native support for Proof General, both for classic Isabelle and
   224 Isabelle/Isar;
   225 
   226 * ML function thm_deps visualizes dependencies of theorems and lemmas,
   227 using the graph browser tool;
   228 
   229 * Isabelle manuals now also available as PDF;
   230 
   231 * theory loader rewritten from scratch (may not be fully
   232 bug-compatible); old loadpath variable has been replaced by show_path,
   233 add_path, del_path, reset_path functions; new operations such as
   234 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
   235 isatool doc ref);
   236 
   237 * improved isatool install: option -k creates KDE application icon,
   238 option -p DIR installs standalone binaries;
   239 
   240 * added ML_PLATFORM setting (useful for cross-platform installations);
   241 more robust handling of platform specific ML images for SML/NJ;
   242 
   243 * the settings environment is now statically scoped, i.e. it is never
   244 created again in sub-processes invoked from isabelle, isatool, or
   245 Isabelle;
   246 
   247 * path element specification '~~' refers to '$ISABELLE_HOME';
   248 
   249 * in locales, the "assumes" and "defines" parts may be omitted if
   250 empty;
   251 
   252 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
   253 long arrows);
   254 
   255 * new print_mode "HTML";
   256 
   257 * new flag show_tags controls display of tags of theorems (which are
   258 basically just comments that may be attached by some tools);
   259 
   260 * Isamode 2.6 requires patch to accomodate change of Isabelle font
   261 mode and goal output format:
   262 
   263 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
   264 244c244
   265 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
   266 ---
   267 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
   268 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
   269 181c181
   270 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
   271 ---
   272 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
   273 
   274 * function bind_thms stores lists of theorems (cf. bind_thm);
   275 
   276 * new shorthand tactics ftac, eatac, datac, fatac;
   277 
   278 * qed (and friends) now accept "" as result name; in that case the
   279 theorem is not stored, but proper checks and presentation of the
   280 result still apply;
   281 
   282 * theorem database now also indexes constants "Trueprop", "all",
   283 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
   284 
   285 
   286 *** HOL ***
   287 
   288 ** HOL arithmetic **
   289 
   290 * There are now decision procedures for linear arithmetic over nat and
   291 int:
   292 
   293 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
   294 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
   295 are treated as atomic; subformulae not involving type `nat' or `int'
   296 are ignored; quantified subformulae are ignored unless they are
   297 positive universal or negative existential. The tactic has to be
   298 invoked by hand and can be a little bit slow. In particular, the
   299 running time is exponential in the number of occurrences of `min' and
   300 `max', and `-' on `nat'.
   301 
   302 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
   303 (negated) (in)equalities among the premises and the conclusion into
   304 account (i.e. no compound formulae) and does not know about `min' and
   305 `max', and `-' on `nat'. It is fast and is used automatically by the
   306 simplifier.
   307 
   308 NB: At the moment, these decision procedures do not cope with mixed
   309 nat/int formulae where the two parts interact, such as `m < n ==>
   310 int(m) < int(n)'.
   311 
   312 * HOL/Numeral provides a generic theory of numerals (encoded
   313 efficiently as bit strings); setup for types nat/int/real is in place;
   314 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
   315 int, existing theories and proof scripts may require a few additional
   316 type constraints;
   317 
   318 * integer division and remainder can now be performed on constant
   319 arguments;
   320 
   321 * many properties of integer multiplication, division and remainder
   322 are now available;
   323 
   324 * An interface to the Stanford Validity Checker (SVC) is available through the
   325 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
   326 are proved automatically.  SVC must be installed separately, and its results
   327 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
   328 invocation of the underlying oracle).  For SVC see
   329   http://verify.stanford.edu/SVC
   330 
   331 * IsaMakefile: the HOL-Real target now builds an actual image;
   332 
   333 
   334 ** HOL misc **
   335 
   336 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
   337 (in Isabelle/Isar) -- by Gertrud Bauer;
   338 
   339 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
   340 analysis for assembly languages with subtypes;
   341 
   342 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
   343 -- avoids syntactic ambiguities and treats state, transition, and
   344 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
   345 changed syntax and (many) tactics;
   346 
   347 * HOL/inductive: Now also handles more general introduction rules such
   348   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
   349   theorems are now maintained within the theory (maintained via the
   350   "mono" attribute);
   351 
   352 * HOL/datatype: Now also handles arbitrarily branching datatypes
   353   (using function types) such as
   354 
   355   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
   356 
   357 * HOL/record: record_simproc (part of the default simpset) takes care
   358 of selectors applied to updated records; record_split_tac is no longer
   359 part of the default claset; update_defs may now be removed from the
   360 simpset in many cases; COMPATIBILITY: old behavior achieved by
   361 
   362   claset_ref () := claset() addSWrapper record_split_wrapper;
   363   Delsimprocs [record_simproc]
   364 
   365 * HOL/typedef: fixed type inference for representing set; type
   366 arguments now have to occur explicitly on the rhs as type constraints;
   367 
   368 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
   369 names rather than an ML expression;
   370 
   371 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
   372 supplied later.  Program schemes can be defined, such as
   373     "While B C s = (if B s then While B C (C s) else s)"
   374 where the well-founded relation can be chosen after B and C have been given.
   375 
   376 * HOL/List: the constructors of type list are now Nil and Cons;
   377 INCOMPATIBILITY: while [] and infix # syntax is still there, of
   378 course, ML tools referring to List.list.op # etc. have to be adapted;
   379 
   380 * HOL_quantifiers flag superseded by "HOL" print mode, which is
   381 disabled by default; run isabelle with option -m HOL to get back to
   382 the original Gordon/HOL-style output;
   383 
   384 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
   385 ALL x<=y. P, EX x<y. P, EX x<=y. P;
   386 
   387 * HOL basic syntax simplified (more orthogonal): all variants of
   388 All/Ex now support plain / symbolic / HOL notation; plain syntax for
   389 Eps operator is provided as well: "SOME x. P[x]";
   390 
   391 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
   392 
   393 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
   394 thus available for user theories;
   395 
   396 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
   397 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
   398 time;
   399 
   400 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
   401 several times and then mp;
   402 
   403 
   404 *** LK ***
   405 
   406 * the notation <<...>> is now available as a notation for sequences of
   407 formulas;
   408 
   409 * the simplifier is now installed
   410 
   411 * the axiom system has been generalized (thanks to Soren Heilmann)
   412 
   413 * the classical reasoner now has a default rule database
   414 
   415 
   416 *** ZF ***
   417 
   418 * new primrec section allows primitive recursive functions to be given
   419 directly (as in HOL) over datatypes and the natural numbers;
   420 
   421 * new tactics induct_tac and exhaust_tac for induction (or case
   422 analysis) over datatypes and the natural numbers;
   423 
   424 * the datatype declaration of type T now defines the recursor T_rec;
   425 
   426 * simplification automatically does freeness reasoning for datatype
   427 constructors;
   428 
   429 * automatic type-inference, with AddTCs command to insert new
   430 type-checking rules;
   431 
   432 * datatype introduction rules are now added as Safe Introduction rules
   433 to the claset;
   434 
   435 * the syntax "if P then x else y" is now available in addition to
   436 if(P,x,y);
   437 
   438 
   439 *** Internal programming interfaces ***
   440 
   441 * tuned simplifier trace output; new flag debug_simp;
   442 
   443 * structures Vartab / Termtab (instances of TableFun) offer efficient
   444 tables indexed by indexname_ord / term_ord (compatible with aconv);
   445 
   446 * AxClass.axclass_tac lost the theory argument;
   447 
   448 * tuned current_goals_markers semantics: begin / end goal avoids
   449 printing empty lines;
   450 
   451 * removed prs and prs_fn hook, which was broken because it did not
   452 include \n in its semantics, forcing writeln to add one
   453 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
   454 string -> unit if you really want to output text without newline;
   455 
   456 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
   457 plain output, interface builders may have to enable 'isabelle_font'
   458 mode to get Isabelle font glyphs as before;
   459 
   460 * refined token_translation interface; INCOMPATIBILITY: output length
   461 now of type real instead of int;
   462 
   463 * theory loader actions may be traced via new ThyInfo.add_hook
   464 interface (see src/Pure/Thy/thy_info.ML); example application: keep
   465 your own database of information attached to *whole* theories -- as
   466 opposed to intra-theory data slots offered via TheoryDataFun;
   467 
   468 * proper handling of dangling sort hypotheses (at last!);
   469 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
   470 extra sort hypotheses that can be witnessed from the type signature;
   471 the force_strip_shyps flag is gone, any remaining shyps are simply
   472 left in the theorem (with a warning issued by strip_shyps_warning);
   473 
   474 
   475 
   476 New in Isabelle98-1 (October 1998)
   477 ----------------------------------
   478 
   479 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   480 
   481 * several changes of automated proof tools;
   482 
   483 * HOL: major changes to the inductive and datatype packages, including
   484 some minor incompatibilities of theory syntax;
   485 
   486 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
   487 called `inj_on';
   488 
   489 * HOL: removed duplicate thms in Arith:
   490   less_imp_add_less  should be replaced by  trans_less_add1
   491   le_imp_add_le      should be replaced by  trans_le_add1
   492 
   493 * HOL: unary minus is now overloaded (new type constraints may be
   494 required);
   495 
   496 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
   497 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
   498 now taken as an integer constant.
   499 
   500 * Pure: ML function 'theory_of' renamed to 'theory';
   501 
   502 
   503 *** Proof tools ***
   504 
   505 * Simplifier:
   506   1. Asm_full_simp_tac is now more aggressive.
   507      1. It will sometimes reorient premises if that increases their power to
   508         simplify.
   509      2. It does no longer proceed strictly from left to right but may also
   510         rotate premises to achieve further simplification.
   511      For compatibility reasons there is now Asm_lr_simp_tac which is like the
   512      old Asm_full_simp_tac in that it does not rotate premises.
   513   2. The simplifier now knows a little bit about nat-arithmetic.
   514 
   515 * Classical reasoner: wrapper mechanism for the classical reasoner now
   516 allows for selected deletion of wrappers, by introduction of names for
   517 wrapper functionals.  This implies that addbefore, addSbefore,
   518 addaltern, and addSaltern now take a pair (name, tactic) as argument,
   519 and that adding two tactics with the same name overwrites the first
   520 one (emitting a warning).
   521   type wrapper = (int -> tactic) -> (int -> tactic)
   522   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
   523   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
   524   delWrapper, delSWrapper: claset *  string            -> claset
   525   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
   526 
   527 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
   528 semantics; addbefore now affects only the unsafe part of step_tac
   529 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
   530 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
   531 by Force_tac;
   532 
   533 * Classical reasoner: setwrapper to setWrapper and compwrapper to
   534 compWrapper; added safe wrapper (and access functions for it);
   535 
   536 * HOL/split_all_tac is now much faster and fails if there is nothing
   537 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
   538 and the names of the automatically generated variables have changed.
   539 split_all_tac has moved within claset() from unsafe wrappers to safe
   540 wrappers, which means that !!-bound variables are split much more
   541 aggressively, and safe_tac and clarify_tac now split such variables.
   542 If this splitting is not appropriate, use delSWrapper "split_all_tac".
   543 Note: the same holds for record_split_tac, which does the job of
   544 split_all_tac for record fields.
   545 
   546 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
   547 permanently to the default simpset using Addsplits just like
   548 Addsimps. They can be removed via Delsplits just like
   549 Delsimps. Lower-case versions are also available.
   550 
   551 * HOL/Simplifier: The rule split_if is now part of the default
   552 simpset. This means that the simplifier will eliminate all occurrences
   553 of if-then-else in the conclusion of a goal. To prevent this, you can
   554 either remove split_if completely from the default simpset by
   555 `Delsplits [split_if]' or remove it in a specific call of the
   556 simplifier using `... delsplits [split_if]'.  You can also add/delete
   557 other case splitting rules to/from the default simpset: every datatype
   558 generates suitable rules `split_t_case' and `split_t_case_asm' (where
   559 t is the name of the datatype).
   560 
   561 * Classical reasoner / Simplifier combination: new force_tac (and
   562 derivatives Force_tac, force) combines rewriting and classical
   563 reasoning (and whatever other tools) similarly to auto_tac, but is
   564 aimed to solve the given subgoal completely.
   565 
   566 
   567 *** General ***
   568 
   569 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
   570 and `goalw': the theory is no longer needed as an explicit argument -
   571 the current theory context is used; assumptions are no longer returned
   572 at the ML-level unless one of them starts with ==> or !!; it is
   573 recommended to convert to these new commands using isatool fixgoal
   574 (backup your sources first!);
   575 
   576 * new top-level commands 'thm' and 'thms' for retrieving theorems from
   577 the current theory context, and 'theory' to lookup stored theories;
   578 
   579 * new theory section 'locale' for declaring constants, assumptions and
   580 definitions that have local scope;
   581 
   582 * new theory section 'nonterminals' for purely syntactic types;
   583 
   584 * new theory section 'setup' for generic ML setup functions
   585 (e.g. package initialization);
   586 
   587 * the distribution now includes Isabelle icons: see
   588 lib/logo/isabelle-{small,tiny}.xpm;
   589 
   590 * isatool install - install binaries with absolute references to
   591 ISABELLE_HOME/bin;
   592 
   593 * isatool logo -- create instances of the Isabelle logo (as EPS);
   594 
   595 * print mode 'emacs' reserved for Isamode;
   596 
   597 * support multiple print (ast) translations per constant name;
   598 
   599 * theorems involving oracles are now printed with a suffixed [!];
   600 
   601 
   602 *** HOL ***
   603 
   604 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
   605 
   606 * HOL/inductive package reorganized and improved: now supports mutual
   607 definitions such as
   608 
   609   inductive EVEN ODD
   610     intrs
   611       null "0 : EVEN"
   612       oddI "n : EVEN ==> Suc n : ODD"
   613       evenI "n : ODD ==> Suc n : EVEN"
   614 
   615 new theorem list "elims" contains an elimination rule for each of the
   616 recursive sets; inductive definitions now handle disjunctive premises
   617 correctly (also ZF);
   618 
   619 INCOMPATIBILITIES: requires Inductive as an ancestor; component
   620 "mutual_induct" no longer exists - the induction rule is always
   621 contained in "induct";
   622 
   623 
   624 * HOL/datatype package re-implemented and greatly improved: now
   625 supports mutually recursive datatypes such as
   626 
   627   datatype
   628     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
   629             | SUM ('a aexp) ('a aexp)
   630             | DIFF ('a aexp) ('a aexp)
   631             | NUM 'a
   632   and
   633     'a bexp = LESS ('a aexp) ('a aexp)
   634             | AND ('a bexp) ('a bexp)
   635             | OR ('a bexp) ('a bexp)
   636 
   637 as well as indirectly recursive datatypes such as
   638 
   639   datatype
   640     ('a, 'b) term = Var 'a
   641                   | App 'b ((('a, 'b) term) list)
   642 
   643 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
   644 induction on mutually / indirectly recursive datatypes.
   645 
   646 Primrec equations are now stored in theory and can be accessed via
   647 <function_name>.simps.
   648 
   649 INCOMPATIBILITIES:
   650 
   651   - Theories using datatypes must now have theory Datatype as an
   652     ancestor.
   653   - The specific <typename>.induct_tac no longer exists - use the
   654     generic induct_tac instead.
   655   - natE has been renamed to nat.exhaust - use exhaust_tac
   656     instead of res_inst_tac ... natE. Note that the variable
   657     names in nat.exhaust differ from the names in natE, this
   658     may cause some "fragile" proofs to fail.
   659   - The theorems split_<typename>_case and split_<typename>_case_asm
   660     have been renamed to <typename>.split and <typename>.split_asm.
   661   - Since default sorts of type variables are now handled correctly,
   662     some datatype definitions may have to be annotated with explicit
   663     sort constraints.
   664   - Primrec definitions no longer require function name and type
   665     of recursive argument.
   666 
   667 Consider using isatool fixdatatype to adapt your theories and proof
   668 scripts to the new package (backup your sources first!).
   669 
   670 
   671 * HOL/record package: considerably improved implementation; now
   672 includes concrete syntax for record types, terms, updates; theorems
   673 for surjective pairing and splitting !!-bound record variables; proof
   674 support is as follows:
   675 
   676   1) standard conversions (selectors or updates applied to record
   677 constructor terms) are part of the standard simpset;
   678 
   679   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
   680 made part of standard simpset and claset via addIffs;
   681 
   682   3) a tactic for record field splitting (record_split_tac) is part of
   683 the standard claset (addSWrapper);
   684 
   685 To get a better idea about these rules you may retrieve them via
   686 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
   687 the name of your record type.
   688 
   689 The split tactic 3) conceptually simplifies by the following rule:
   690 
   691   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
   692 
   693 Thus any record variable that is bound by meta-all will automatically
   694 blow up into some record constructor term, consequently the
   695 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
   696 solve record problems automatically.
   697 
   698 
   699 * reorganized the main HOL image: HOL/Integ and String loaded by
   700 default; theory Main includes everything;
   701 
   702 * automatic simplification of integer sums and comparisons, using cancellation;
   703 
   704 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
   705 
   706 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
   707 
   708 * many new identities for unions, intersections, set difference, etc.;
   709 
   710 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
   711 called split_if, split_split, split_sum_case and split_nat_case (to go
   712 with add/delsplits);
   713 
   714 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
   715 (?x::unit) = (); this is made part of the default simpset, which COULD
   716 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
   717 'Delsimprocs [unit_eq_proc];' as last resort); also note that
   718 unit_abs_eta_conv is added in order to counter the effect of
   719 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
   720 %u.f();
   721 
   722 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
   723 makes more sense);
   724 
   725 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   726   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   727   disjointness reasoning but breaking a few old proofs.
   728 
   729 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
   730 to 'converse' from 'inverse' (for compatibility with ZF and some
   731 literature);
   732 
   733 * HOL/recdef can now declare non-recursive functions, with {} supplied as
   734 the well-founded relation;
   735 
   736 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
   737     Compl A.  The "Compl" syntax remains available as input syntax for this
   738     release ONLY.
   739 
   740 * HOL/Update: new theory of function updates:
   741     f(a:=b) == %x. if x=a then b else f x
   742 may also be iterated as in f(a:=b,c:=d,...);
   743 
   744 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
   745 
   746 * HOL/List:
   747   - new function list_update written xs[i:=v] that updates the i-th
   748     list position. May also be iterated as in xs[i:=a,j:=b,...].
   749   - new function `upt' written [i..j(] which generates the list
   750     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
   751     bound write [i..j], which is a shorthand for [i..j+1(].
   752   - new lexicographic orderings and corresponding wellfoundedness theorems.
   753 
   754 * HOL/Arith:
   755   - removed 'pred' (predecessor) function;
   756   - generalized some theorems about n-1;
   757   - many new laws about "div" and "mod";
   758   - new laws about greatest common divisors (see theory ex/Primes);
   759 
   760 * HOL/Relation: renamed the relational operator r^-1 "converse"
   761 instead of "inverse";
   762 
   763 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
   764   of the multiset ordering;
   765 
   766 * directory HOL/Real: a construction of the reals using Dedekind cuts
   767   (not included by default);
   768 
   769 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
   770 
   771 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
   772   programs, i.e. different program variables may have different types.
   773 
   774 * calling (stac rew i) now fails if "rew" has no effect on the goal
   775   [previously, this check worked only if the rewrite rule was unconditional]
   776   Now rew can involve either definitions or equalities (either == or =).
   777 
   778 
   779 *** ZF ***
   780 
   781 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
   782   only the theorems proved on ZF.ML;
   783 
   784 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
   785   It and 'sym RS equals0D' are now in the default  claset, giving automatic
   786   disjointness reasoning but breaking a few old proofs.
   787 
   788 * ZF/Update: new theory of function updates
   789     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
   790   may also be iterated as in f(a:=b,c:=d,...);
   791 
   792 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
   793 
   794 * calling (stac rew i) now fails if "rew" has no effect on the goal
   795   [previously, this check worked only if the rewrite rule was unconditional]
   796   Now rew can involve either definitions or equalities (either == or =).
   797 
   798 * case_tac provided for compatibility with HOL
   799     (like the old excluded_middle_tac, but with subgoals swapped)
   800 
   801 
   802 *** Internal programming interfaces ***
   803 
   804 * Pure: several new basic modules made available for general use, see
   805 also src/Pure/README;
   806 
   807 * improved the theory data mechanism to support encapsulation (data
   808 kind name replaced by private Object.kind, acting as authorization
   809 key); new type-safe user interface via functor TheoryDataFun; generic
   810 print_data function becomes basically useless;
   811 
   812 * removed global_names compatibility flag -- all theory declarations
   813 are qualified by default;
   814 
   815 * module Pure/Syntax now offers quote / antiquote translation
   816 functions (useful for Hoare logic etc. with implicit dependencies);
   817 see HOL/ex/Antiquote for an example use;
   818 
   819 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
   820 cterm -> thm;
   821 
   822 * new tactical CHANGED_GOAL for checking that a tactic modifies a
   823 subgoal;
   824 
   825 * Display.print_goals function moved to Locale.print_goals;
   826 
   827 * standard print function for goals supports current_goals_markers
   828 variable for marking begin of proof, end of proof, start of goal; the
   829 default is ("", "", ""); setting current_goals_markers := ("<proof>",
   830 "</proof>", "<goal>") causes SGML like tagged proof state printing,
   831 for example;
   832 
   833 
   834 
   835 New in Isabelle98 (January 1998)
   836 --------------------------------
   837 
   838 *** Overview of INCOMPATIBILITIES (see below for more details) ***
   839 
   840 * changed lexical syntax of terms / types: dots made part of long
   841 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
   842 
   843 * simpset (and claset) reference variable replaced by functions
   844 simpset / simpset_ref;
   845 
   846 * no longer supports theory aliases (via merge) and non-trivial
   847 implicit merge of thms' signatures;
   848 
   849 * most internal names of constants changed due to qualified names;
   850 
   851 * changed Pure/Sequence interface (see Pure/seq.ML);
   852 
   853 
   854 *** General Changes ***
   855 
   856 * hierachically structured name spaces (for consts, types, axms, thms
   857 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
   858 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
   859 isatool fixdots ensures space after dots (e.g. "%x. x"); set
   860 long_names for fully qualified output names; NOTE: ML programs
   861 (special tactics, packages etc.) referring to internal names may have
   862 to be adapted to cope with fully qualified names; in case of severe
   863 backward campatibility problems try setting 'global_names' at compile
   864 time to have enrything declared within a flat name space; one may also
   865 fine tune name declarations in theories via the 'global' and 'local'
   866 section;
   867 
   868 * reimplemented the implicit simpset and claset using the new anytype
   869 data filed in signatures; references simpset:simpset ref etc. are
   870 replaced by functions simpset:unit->simpset and
   871 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
   872 to patch your ML files accordingly;
   873 
   874 * HTML output now includes theory graph data for display with Java
   875 applet or isatool browser; data generated automatically via isatool
   876 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
   877 
   878 * defs may now be conditional; improved rewrite_goals_tac to handle
   879 conditional equations;
   880 
   881 * defs now admits additional type arguments, using TYPE('a) syntax;
   882 
   883 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
   884 creates a new theory node; implicit merge of thms' signatures is
   885 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
   886 transfer:theory->thm->thm in (rare) cases;
   887 
   888 * improved handling of draft signatures / theories; draft thms (and
   889 ctyps, cterms) are automatically promoted to real ones;
   890 
   891 * slightly changed interfaces for oracles: admit many per theory, named
   892 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
   893 
   894 * print_goals: optional output of const types (set show_consts and
   895 show_types);
   896 
   897 * improved output of warnings (###) and errors (***);
   898 
   899 * subgoal_tac displays a warning if the new subgoal has type variables;
   900 
   901 * removed old README and Makefiles;
   902 
   903 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
   904 
   905 * removed obsolete init_pps and init_database;
   906 
   907 * deleted the obsolete tactical STATE, which was declared by
   908     fun STATE tacfun st = tacfun st st;
   909 
   910 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
   911 (which abbreviates $HOME);
   912 
   913 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
   914 use isatool fixseq to adapt your ML programs (this works for fully
   915 qualified references to the Sequence structure only!);
   916 
   917 * use_thy no longer requires writable current directory; it always
   918 reloads .ML *and* .thy file, if either one is out of date;
   919 
   920 
   921 *** Classical Reasoner ***
   922 
   923 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
   924 tactics that use classical reasoning to simplify a subgoal without
   925 splitting it into several subgoals;
   926 
   927 * Safe_tac: like safe_tac but uses the default claset;
   928 
   929 
   930 *** Simplifier ***
   931 
   932 * added simplification meta rules:
   933     (asm_)(full_)simplify: simpset -> thm -> thm;
   934 
   935 * simplifier.ML no longer part of Pure -- has to be loaded by object
   936 logics (again);
   937 
   938 * added prems argument to simplification procedures;
   939 
   940 * HOL, FOL, ZF: added infix function `addsplits':
   941   instead of `<simpset> setloop (split_tac <thms>)'
   942   you can simply write `<simpset> addsplits <thms>'
   943 
   944 
   945 *** Syntax ***
   946 
   947 * TYPE('a) syntax for type reflection terms;
   948 
   949 * no longer handles consts with name "" -- declare as 'syntax' instead;
   950 
   951 * pretty printer: changed order of mixfix annotation preference (again!);
   952 
   953 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
   954 
   955 
   956 *** HOL ***
   957 
   958 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
   959   with `addloop' of the simplifier to faciliate case splitting in premises.
   960 
   961 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
   962 
   963 * HOL/Auth: new protocol proofs including some for the Internet
   964   protocol TLS;
   965 
   966 * HOL/Map: new theory of `maps' a la VDM;
   967 
   968 * HOL/simplifier: simplification procedures nat_cancel_sums for
   969 cancelling out common nat summands from =, <, <= (in)equalities, or
   970 differences; simplification procedures nat_cancel_factor for
   971 cancelling common factor from =, <, <= (in)equalities over natural
   972 sums; nat_cancel contains both kinds of procedures, it is installed by
   973 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
   974 
   975 * HOL/simplifier: terms of the form
   976   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
   977   are rewritten to
   978   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
   979   and those of the form
   980   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
   981   are rewritten to
   982   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
   983 
   984 * HOL/datatype
   985   Each datatype `t' now comes with a theorem `split_t_case' of the form
   986 
   987   P(t_case f1 ... fn x) =
   988      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
   989         ...
   990        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
   991      )
   992 
   993   and a theorem `split_t_case_asm' of the form
   994 
   995   P(t_case f1 ... fn x) =
   996     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
   997         ...
   998        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
   999      )
  1000   which can be added to a simpset via `addsplits'. The existing theorems
  1001   expand_list_case and expand_option_case have been renamed to
  1002   split_list_case and split_option_case.
  1003 
  1004 * HOL/Arithmetic:
  1005   - `pred n' is automatically converted to `n-1'.
  1006     Users are strongly encouraged not to use `pred' any longer,
  1007     because it will disappear altogether at some point.
  1008   - Users are strongly encouraged to write "0 < n" rather than
  1009     "n ~= 0". Theorems and proof tools have been modified towards this
  1010     `standard'.
  1011 
  1012 * HOL/Lists:
  1013   the function "set_of_list" has been renamed "set" (and its theorems too);
  1014   the function "nth" now takes its arguments in the reverse order and
  1015   has acquired the infix notation "!" as in "xs!n".
  1016 
  1017 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  1018 
  1019 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  1020   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  1021 
  1022 * HOL/record: extensible records with schematic structural subtyping
  1023 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  1024 still lacks various theorems and concrete record syntax;
  1025 
  1026 
  1027 *** HOLCF ***
  1028 
  1029 * removed "axioms" and "generated by" sections;
  1030 
  1031 * replaced "ops" section by extended "consts" section, which is capable of
  1032   handling the continuous function space "->" directly;
  1033 
  1034 * domain package:
  1035   . proves theorems immediately and stores them in the theory,
  1036   . creates hierachical name space,
  1037   . now uses normal mixfix annotations (instead of cinfix...),
  1038   . minor changes to some names and values (for consistency),
  1039   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  1040   . separator between mutual domain defs: changed "," to "and",
  1041   . improved handling of sort constraints;  now they have to
  1042     appear on the left-hand side of the equations only;
  1043 
  1044 * fixed LAM <x,y,zs>.b syntax;
  1045 
  1046 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  1047 adm (%x. P (t x)), where P is chainfinite and t continuous;
  1048 
  1049 
  1050 *** FOL and ZF ***
  1051 
  1052 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  1053   with `addloop' of the simplifier to faciliate case splitting in premises.
  1054 
  1055 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  1056 in HOL, they strip ALL and --> from proved theorems;
  1057 
  1058 
  1059 
  1060 New in Isabelle94-8 (May 1997)
  1061 ------------------------------
  1062 
  1063 *** General Changes ***
  1064 
  1065 * new utilities to build / run / maintain Isabelle etc. (in parts
  1066 still somewhat experimental); old Makefiles etc. still functional;
  1067 
  1068 * new 'Isabelle System Manual';
  1069 
  1070 * INSTALL text, together with ./configure and ./build scripts;
  1071 
  1072 * reimplemented type inference for greater efficiency, better error
  1073 messages and clean internal interface;
  1074 
  1075 * prlim command for dealing with lots of subgoals (an easier way of
  1076 setting goals_limit);
  1077 
  1078 
  1079 *** Syntax ***
  1080 
  1081 * supports alternative (named) syntax tables (parser and pretty
  1082 printer); internal interface is provided by add_modesyntax(_i);
  1083 
  1084 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  1085 be used in conjunction with the Isabelle symbol font; uses the
  1086 "symbols" syntax table;
  1087 
  1088 * added token_translation interface (may translate name tokens in
  1089 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  1090 the current print_mode); IMPORTANT: user print translation functions
  1091 are responsible for marking newly introduced bounds
  1092 (Syntax.mark_boundT);
  1093 
  1094 * token translations for modes "xterm" and "xterm_color" that display
  1095 names in bold, underline etc. or colors (which requires a color
  1096 version of xterm);
  1097 
  1098 * infixes may now be declared with names independent of their syntax;
  1099 
  1100 * added typed_print_translation (like print_translation, but may
  1101 access type of constant);
  1102 
  1103 
  1104 *** Classical Reasoner ***
  1105 
  1106 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  1107 some limitations.  Blast_tac...
  1108   + ignores addss, addbefore, addafter; this restriction is intrinsic
  1109   + ignores elimination rules that don't have the correct format
  1110         (the conclusion MUST be a formula variable)
  1111   + ignores types, which can make HOL proofs fail
  1112   + rules must not require higher-order unification, e.g. apply_type in ZF
  1113     [message "Function Var's argument not a bound variable" relates to this]
  1114   + its proof strategy is more general but can actually be slower
  1115 
  1116 * substitution with equality assumptions no longer permutes other
  1117 assumptions;
  1118 
  1119 * minor changes in semantics of addafter (now called addaltern); renamed
  1120 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  1121 (and access functions for it);
  1122 
  1123 * improved combination of classical reasoner and simplifier:
  1124   + functions for handling clasimpsets
  1125   + improvement of addss: now the simplifier is called _after_ the
  1126     safe steps.
  1127   + safe variant of addss called addSss: uses safe simplifications
  1128     _during_ the safe steps. It is more complete as it allows multiple
  1129     instantiations of unknowns (e.g. with slow_tac).
  1130 
  1131 *** Simplifier ***
  1132 
  1133 * added interface for simplification procedures (functions that
  1134 produce *proven* rewrite rules on the fly, depending on current
  1135 redex);
  1136 
  1137 * ordering on terms as parameter (used for ordered rewriting);
  1138 
  1139 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  1140 
  1141 * the solver is now split into a safe and an unsafe part.
  1142 This should be invisible for the normal user, except that the
  1143 functions setsolver and addsolver have been renamed to setSolver and
  1144 addSolver; added safe_asm_full_simp_tac;
  1145 
  1146 
  1147 *** HOL ***
  1148 
  1149 * a generic induction tactic `induct_tac' which works for all datatypes and
  1150 also for type `nat';
  1151 
  1152 * a generic case distinction tactic `exhaust_tac' which works for all
  1153 datatypes and also for type `nat';
  1154 
  1155 * each datatype comes with a function `size';
  1156 
  1157 * patterns in case expressions allow tuple patterns as arguments to
  1158 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  1159 
  1160 * primrec now also works with type nat;
  1161 
  1162 * recdef: a new declaration form, allows general recursive functions to be
  1163 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  1164 
  1165 * the constant for negation has been renamed from "not" to "Not" to
  1166 harmonize with FOL, ZF, LK, etc.;
  1167 
  1168 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  1169 infinite lists;
  1170 
  1171 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  1172 
  1173 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  1174 problems in commutative rings, using axiomatic type classes for + and *;
  1175 
  1176 * more examples in HOL/MiniML and HOL/Auth;
  1177 
  1178 * more default rewrite rules for quantifiers, union/intersection;
  1179 
  1180 * a new constant `arbitrary == @x.False';
  1181 
  1182 * HOLCF/IOA replaces old HOL/IOA;
  1183 
  1184 * HOLCF changes: derived all rules and arities
  1185   + axiomatic type classes instead of classes
  1186   + typedef instead of faking type definitions
  1187   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  1188   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  1189   + eliminated the types void, one, tr
  1190   + use unit lift and bool lift (with translations) instead of one and tr
  1191   + eliminated blift from Lift3.thy (use Def instead of blift)
  1192   all eliminated rules are derived as theorems --> no visible changes ;
  1193 
  1194 
  1195 *** ZF ***
  1196 
  1197 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  1198 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  1199 as ZF_cs addSIs [equalityI];
  1200 
  1201 
  1202 
  1203 New in Isabelle94-7 (November 96)
  1204 ---------------------------------
  1205 
  1206 * allowing negative levels (as offsets) in prlev and choplev;
  1207 
  1208 * super-linear speedup for large simplifications;
  1209 
  1210 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  1211 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  1212 FAIL); can suppress it using the command Delsimps (ex_simps @
  1213 all_simps); De Morgan laws are also now included, by default;
  1214 
  1215 * improved printing of ==>  :  ~:
  1216 
  1217 * new object-logic "Sequents" adds linear logic, while replacing LK
  1218 and Modal (thanks to Sara Kalvala);
  1219 
  1220 * HOL/Auth: correctness proofs for authentication protocols;
  1221 
  1222 * HOL: new auto_tac combines rewriting and classical reasoning (many
  1223 examples on HOL/Auth);
  1224 
  1225 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  1226 the rewriter and classical reasoner simultaneously;
  1227 
  1228 * function uresult no longer returns theorems in "standard" format;
  1229 regain previous version by: val uresult = standard o uresult;
  1230 
  1231 
  1232 
  1233 New in Isabelle94-6
  1234 -------------------
  1235 
  1236 * oracles -- these establish an interface between Isabelle and trusted
  1237 external reasoners, which may deliver results as theorems;
  1238 
  1239 * proof objects (in particular record all uses of oracles);
  1240 
  1241 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  1242 
  1243 * "constdefs" section in theory files;
  1244 
  1245 * "primrec" section (HOL) no longer requires names;
  1246 
  1247 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  1248 
  1249 
  1250 
  1251 New in Isabelle94-5
  1252 -------------------
  1253 
  1254 * reduced space requirements;
  1255 
  1256 * automatic HTML generation from theories;
  1257 
  1258 * theory files no longer require "..." (quotes) around most types;
  1259 
  1260 * new examples, including two proofs of the Church-Rosser theorem;
  1261 
  1262 * non-curried (1994) version of HOL is no longer distributed;
  1263 
  1264 
  1265 
  1266 New in Isabelle94-4
  1267 -------------------
  1268 
  1269 * greatly reduced space requirements;
  1270 
  1271 * theory files (.thy) no longer require \...\ escapes at line breaks;
  1272 
  1273 * searchable theorem database (see the section "Retrieving theorems" on
  1274 page 8 of the Reference Manual);
  1275 
  1276 * new examples, including Grabczewski's monumental case study of the
  1277 Axiom of Choice;
  1278 
  1279 * The previous version of HOL renamed to Old_HOL;
  1280 
  1281 * The new version of HOL (previously called CHOL) uses a curried syntax
  1282 for functions.  Application looks like f a b instead of f(a,b);
  1283 
  1284 * Mutually recursive inductive definitions finally work in HOL;
  1285 
  1286 * In ZF, pattern-matching on tuples is now available in all abstractions and
  1287 translates to the operator "split";
  1288 
  1289 
  1290 
  1291 New in Isabelle94-3
  1292 -------------------
  1293 
  1294 * new infix operator, addss, allowing the classical reasoner to
  1295 perform simplification at each step of its search.  Example:
  1296         fast_tac (cs addss ss)
  1297 
  1298 * a new logic, CHOL, the same as HOL, but with a curried syntax
  1299 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  1300 look like (a,b) instead of <a,b>;
  1301 
  1302 * PLEASE NOTE: CHOL will eventually replace HOL!
  1303 
  1304 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  1305 It translates to the operator "split".  A new theory of integers is available;
  1306 
  1307 * In ZF, integer numerals now denote two's-complement binary integers.
  1308 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  1309 
  1310 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  1311 of the Axiom of Choice;
  1312 
  1313 
  1314 
  1315 New in Isabelle94-2
  1316 -------------------
  1317 
  1318 * Significantly faster resolution;
  1319 
  1320 * the different sections in a .thy file can now be mixed and repeated
  1321 freely;
  1322 
  1323 * Database of theorems for FOL, HOL and ZF.  New
  1324 commands including qed, qed_goal and bind_thm store theorems in the database.
  1325 
  1326 * Simple database queries: return a named theorem (get_thm) or all theorems of
  1327 a given theory (thms_of), or find out what theory a theorem was proved in
  1328 (theory_of_thm);
  1329 
  1330 * Bugs fixed in the inductive definition and datatype packages;
  1331 
  1332 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  1333 and HOL_dup_cs obsolete;
  1334 
  1335 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  1336 have been removed;
  1337 
  1338 * Simpler definition of function space in ZF;
  1339 
  1340 * new results about cardinal and ordinal arithmetic in ZF;
  1341 
  1342 * 'subtype' facility in HOL for introducing new types as subsets of existing
  1343 types;
  1344 
  1345 
  1346 $Id$