NEWS
author skalberg
Thu Oct 09 18:20:14 2003 +0200 (2003-10-09)
changeset 14224 442c097c1437
parent 14211 7286c187596d
child 14233 f6b6b2c55141
permissions -rw-r--r--
Added info on the new 'finalconsts' command.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    10   (\<aa>...\<zz>\<AA>...\<ZZ>), caligraphic (\<A>...\<Z>), and euler
    11   (\<a>...\<z>), are now considered normal letters, and can therefore
    12   be used anywhere where an ASCII letter (a...zA...Z) has until
    13   now. COMPATIBILITY: This obviously changes the parsing of some
    14   terms, especially where a symbol has been used as a binder, say
    15   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    16   as an identifier.  Fix it by inserting a space around former
    17   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    18   existing theory and ML files.
    19 
    20 * Pure: Using the functions Theory.add_finals or Theory.add_finals_i
    21   or the new Isar command "finalconsts", it is now possible to
    22   make constants "final", thereby ensuring that they are not defined
    23   later.  Useful for constants whose behaviour is fixed axiomatically
    24   rather than definitionally, such as the meta-logic connectives.
    25 
    26 *** Isar ***
    27 
    28 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    29   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    30     locales are no longer forced to write Isar proof scripts.
    31     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    32     emulations.
    33   - INCOMPATIBILITY: names of variables to be instantiated may no
    34     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    35     This is consistent with the instantiation attribute "where".
    36 
    37 * Locales:
    38   - Goal statements involving the context element "includes" no longer
    39     generate theorems with internal delta predicates (those ending on
    40     "_axioms") in the premise.
    41     Resolve particular premise with <locale>.intro to obtain old form.
    42   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    43     specification and "includes" elements in goal statement.
    44 
    45 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    46   (Isar) contexts.
    47 
    48 *** HOL ***
    49 
    50 * 'specification' command added, allowing for definition by
    51   specification.  There is also an 'ax_specification' command that
    52   introduces the new constants axiomatically.
    53 
    54 * SET-Protocol: formalization and verification of the SET protocol suite;
    55 
    56 
    57 New in Isabelle2003 (May 2003)
    58 --------------------------------
    59 
    60 *** General ***
    61 
    62 * Provers/simplifier:
    63 
    64   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    65     Assumptions are now subject to complete mutual simplification,
    66     not just from left to right. The simplifier now preserves
    67     the order of assumptions.
    68 
    69     Potential INCOMPATIBILITY:
    70 
    71     -- simp sometimes diverges where the old version did
    72        not, e.g. invoking simp on the goal
    73 
    74         [| P (f x); y = x; f x = f y |] ==> Q
    75 
    76        now gives rise to the infinite reduction sequence
    77 
    78         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    79 
    80        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    81        kind of problem.
    82 
    83     -- Tactics combining classical reasoner and simplification (such as auto)
    84        are also affected by this change, because many of them rely on
    85        simp. They may sometimes diverge as well or yield a different numbers
    86        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    87        in case of problems. Sometimes subsequent calls to the classical
    88        reasoner will fail because a preceeding call to the simplifier too
    89        eagerly simplified the goal, e.g. deleted redundant premises.
    90 
    91   - The simplifier trace now shows the names of the applied rewrite rules
    92 
    93   - You can limit the number of recursive invocations of the simplifier
    94     during conditional rewriting (where the simplifie tries to solve the
    95     conditions before applying the rewrite rule):
    96     ML "simp_depth_limit := n"
    97     where n is an integer. Thus you can force termination where previously
    98     the simplifier would diverge.
    99 
   100   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   101 
   102   - No longer aborts on failed congruence proof.  Instead, the
   103     congruence is ignored.
   104 
   105 * Pure: New generic framework for extracting programs from constructive
   106   proofs. See HOL/Extraction.thy for an example instantiation, as well
   107   as HOL/Extraction for some case studies.
   108 
   109 * Pure: The main goal of the proof state is no longer shown by default, only
   110 the subgoals. This behaviour is controlled by a new flag.
   111    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   112 (ML: Proof.show_main_goal).
   113 
   114 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   115 rules whose conclusion matches subgoal 1:
   116       PG menu: Isabelle/Isar -> Show me -> matching rules
   117 The rules are ordered by how closely they match the subgoal.
   118 In particular, rules that solve a subgoal outright are displayed first
   119 (or rather last, the way they are printed).
   120 (ML: ProofGeneral.print_intros())
   121 
   122 * Pure: New flag trace_unify_fail causes unification to print
   123 diagnostic information (PG: in trace buffer) when it fails. This is
   124 useful for figuring out why single step proofs like rule, erule or
   125 assumption failed.
   126 
   127 * Pure: Locale specifications now produce predicate definitions
   128 according to the body of text (covering assumptions modulo local
   129 definitions); predicate "loc_axioms" covers newly introduced text,
   130 while "loc" is cumulative wrt. all included locale expressions; the
   131 latter view is presented only on export into the global theory
   132 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   133 on the old view without predicates;
   134 
   135 * Pure: predefined locales "var" and "struct" are useful for sharing
   136 parameters (as in CASL, for example); just specify something like
   137 ``var x + var y + struct M'' as import;
   138 
   139 * Pure: improved thms_containing: proper indexing of facts instead of
   140 raw theorems; check validity of results wrt. current name space;
   141 include local facts of proof configuration (also covers active
   142 locales), cover fixed variables in index; may use "_" in term
   143 specification; an optional limit for the number of printed facts may
   144 be given (the default is 40);
   145 
   146 * Pure: disallow duplicate fact bindings within new-style theory files
   147 (batch-mode only);
   148 
   149 * Provers: improved induct method: assumptions introduced by case
   150 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   151 the goal statement); "foo" still refers to all facts collectively;
   152 
   153 * Provers: the function blast.overloaded has been removed: all constants
   154 are regarded as potentially overloaded, which improves robustness in exchange
   155 for slight decrease in efficiency;
   156 
   157 * Provers/linorder: New generic prover for transitivity reasoning over
   158 linear orders.  Note: this prover is not efficient!
   159 
   160 * Isar: preview of problems to finish 'show' now produce an error
   161 rather than just a warning (in interactive mode);
   162 
   163 
   164 *** HOL ***
   165 
   166 * arith(_tac)
   167 
   168  - Produces a counter example if it cannot prove a goal.
   169    Note that the counter example may be spurious if the goal is not a formula
   170    of quantifier-free linear arithmetic.
   171    In ProofGeneral the counter example appears in the trace buffer.
   172 
   173  - Knows about div k and mod k where k is a numeral of type nat or int.
   174 
   175  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   176    linear arithmetic fails. This takes account of quantifiers and divisibility.
   177    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   178 
   179 * simp's arithmetic capabilities have been enhanced a bit: it now
   180 takes ~= in premises into account (by performing a case split);
   181 
   182 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   183 are distributed over a sum of terms;
   184 
   185 * New tactic "trans_tac" and method "trans" instantiate
   186 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   187 "<=", "<" and "="). 
   188 
   189 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   190 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   191 
   192 * 'typedef' command has new option "open" to suppress the set
   193 definition;
   194 
   195 * functions Min and Max on finite sets have been introduced (theory
   196 Finite_Set);
   197 
   198 * attribute [symmetric] now works for relations as well; it turns
   199 (x,y) : R^-1 into (y,x) : R, and vice versa;
   200 
   201 * induct over a !!-quantified statement (say !!x1..xn):
   202   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   203 
   204 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   205 %x. None. Warning: empty_def now refers to the previously hidden definition
   206 of the empty set.
   207 
   208 * Algebra: formalization of classical algebra.  Intended as base for
   209 any algebraic development in Isabelle.  Currently covers group theory
   210 (up to Sylow's theorem) and ring theory (Universal Property of
   211 Univariate Polynomials).  Contributions welcome;
   212 
   213 * GroupTheory: deleted, since its material has been moved to Algebra;
   214 
   215 * Complex: new directory of the complex numbers with numeric constants, 
   216 nonstandard complex numbers, and some complex analysis, standard and 
   217 nonstandard (Jacques Fleuriot);
   218 
   219 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   220 
   221 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   222 Fleuriot);
   223 
   224 * Real/HahnBanach: updated and adapted to locales;
   225 
   226 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   227 Gray and Kramer);
   228 
   229 * UNITY: added the Meier-Sanders theory of progress sets;
   230 
   231 * MicroJava: bytecode verifier and lightweight bytecode verifier
   232 as abstract algorithms, instantiated to the JVM;
   233 
   234 * Bali: Java source language formalization. Type system, operational
   235 semantics, axiomatic semantics. Supported language features:
   236 classes, interfaces, objects,virtual methods, static methods,
   237 static/instance fields, arrays, access modifiers, definite
   238 assignment, exceptions.
   239 
   240 
   241 *** ZF ***
   242 
   243 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   244 universe, etc.);
   245 
   246 * Main ZF: virtually all theories converted to new-style format;
   247 
   248 
   249 *** ML ***
   250 
   251 * Pure: Tactic.prove provides sane interface for internal proofs;
   252 omits the infamous "standard" operation, so this is more appropriate
   253 than prove_goalw_cterm in many situations (e.g. in simprocs);
   254 
   255 * Pure: improved error reporting of simprocs;
   256 
   257 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   258 up simprocs;
   259 
   260 
   261 *** Document preparation ***
   262 
   263 * uses \par instead of \\ for line breaks in theory text. This may
   264 shift some page breaks in large documents. To get the old behaviour
   265 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   266 
   267 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   268 other packages
   269 
   270 * \<euro> now needs package babel/greek instead of marvosym (which
   271 broke \Rightarrow)
   272 
   273 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   274 textcomp package)
   275 
   276 
   277 New in Isabelle2002 (March 2002)
   278 --------------------------------
   279 
   280 *** Document preparation ***
   281 
   282 * greatly simplified document preparation setup, including more
   283 graceful interpretation of isatool usedir -i/-d/-D options, and more
   284 instructive isatool mkdir; users should basically be able to get
   285 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   286 users may run a separate document processing stage manually like this:
   287 "isatool usedir -D output HOL Test && isatool document Test/output";
   288 
   289 * theory dependency graph may now be incorporated into documents;
   290 isatool usedir -g true will produce session_graph.eps/.pdf for use
   291 with \includegraphics of LaTeX;
   292 
   293 * proper spacing of consecutive markup elements, especially text
   294 blocks after section headings;
   295 
   296 * support bold style (for single symbols only), input syntax is like
   297 this: "\<^bold>\<alpha>" or "\<^bold>A";
   298 
   299 * \<bullet> is now output as bold \cdot by default, which looks much
   300 better in printed text;
   301 
   302 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   303 note that these symbols are currently unavailable in Proof General /
   304 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   305 
   306 * isatool latex no longer depends on changed TEXINPUTS, instead
   307 isatool document copies the Isabelle style files to the target
   308 location;
   309 
   310 
   311 *** Isar ***
   312 
   313 * Pure/Provers: improved proof by cases and induction;
   314   - 'case' command admits impromptu naming of parameters (such as
   315     "case (Suc n)");
   316   - 'induct' method divinates rule instantiation from the inductive
   317     claim; no longer requires excessive ?P bindings for proper
   318     instantiation of cases;
   319   - 'induct' method properly enumerates all possibilities of set/type
   320     rules; as a consequence facts may be also passed through *type*
   321     rules without further ado;
   322   - 'induct' method now derives symbolic cases from the *rulified*
   323     rule (before it used to rulify cases stemming from the internal
   324     atomized version); this means that the context of a non-atomic
   325     statement becomes is included in the hypothesis, avoiding the
   326     slightly cumbersome show "PROP ?case" form;
   327   - 'induct' may now use elim-style induction rules without chaining
   328     facts, using ``missing'' premises from the goal state; this allows
   329     rules stemming from inductive sets to be applied in unstructured
   330     scripts, while still benefitting from proper handling of non-atomic
   331     statements; NB: major inductive premises need to be put first, all
   332     the rest of the goal is passed through the induction;
   333   - 'induct' proper support for mutual induction involving non-atomic
   334     rule statements (uses the new concept of simultaneous goals, see
   335     below);
   336   - append all possible rule selections, but only use the first
   337     success (no backtracking);
   338   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   339   - undeclared rule case names default to numbers 1, 2, 3, ...;
   340   - added 'print_induct_rules' (covered by help item in recent Proof
   341     General versions);
   342   - moved induct/cases attributes to Pure, methods to Provers;
   343   - generic method setup instantiated for FOL and HOL;
   344 
   345 * Pure: support multiple simultaneous goal statements, for example
   346 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   347 meta-level mechanism, this acts as if several individual goals had
   348 been stated separately; in particular common proof methods need to be
   349 repeated in order to cover all claims; note that a single elimination
   350 step is *not* sufficient to establish the two conjunctions, so this
   351 fails:
   352 
   353   assume "A & B" then have A and B ..   (*".." fails*)
   354 
   355 better use "obtain" in situations as above; alternative refer to
   356 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   357 
   358 * Pure: proper integration with ``locales''; unlike the original
   359 version by Florian Kammüller, Isar locales package high-level proof
   360 contexts rather than raw logical ones (e.g. we admit to include
   361 attributes everywhere); operations on locales include merge and
   362 rename; support for implicit arguments (``structures''); simultaneous
   363 type-inference over imports and text; see also HOL/ex/Locales.thy for
   364 some examples;
   365 
   366 * Pure: the following commands have been ``localized'', supporting a
   367 target locale specification "(in name)": 'lemma', 'theorem',
   368 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   369 stored both within the locale and at the theory level (exported and
   370 qualified by the locale name);
   371 
   372 * Pure: theory goals may now be specified in ``long'' form, with
   373 ad-hoc contexts consisting of arbitrary locale elements. for example
   374 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   375 definitions may be given, too); the result is a meta-level rule with
   376 the context elements being discharged in the obvious way;
   377 
   378 * Pure: new proof command 'using' allows to augment currently used
   379 facts after a goal statement ('using' is syntactically analogous to
   380 'apply', but acts on the goal's facts only); this allows chained facts
   381 to be separated into parts given before and after a claim, as in
   382 ``from a and b have C using d and e <proof>'';
   383 
   384 * Pure: renamed "antecedent" case to "rule_context";
   385 
   386 * Pure: new 'judgment' command records explicit information about the
   387 object-logic embedding (used by several tools internally); no longer
   388 use hard-wired "Trueprop";
   389 
   390 * Pure: added 'corollary' command;
   391 
   392 * Pure: fixed 'token_translation' command;
   393 
   394 * Pure: removed obsolete 'exported' attribute;
   395 
   396 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   397 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   398 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   399 
   400 * Pure: method 'atomize' presents local goal premises as object-level
   401 statements (atomic meta-level propositions); setup controlled via
   402 rewrite rules declarations of 'atomize' attribute; example
   403 application: 'induct' method with proper rule statements in improper
   404 proof *scripts*;
   405 
   406 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   407 now consider the syntactic context of assumptions, giving a better
   408 chance to get type-inference of the arguments right (this is
   409 especially important for locales);
   410 
   411 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   412 mode;
   413 
   414 * Pure/obtain: the formal conclusion "thesis", being marked as
   415 ``internal'', may no longer be reference directly in the text;
   416 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   417 situations;
   418 
   419 * Pure: generic 'sym' attribute which declares a rule both as pure
   420 'elim?' and for the 'symmetric' operation;
   421 
   422 * Pure: marginal comments ``--'' may now occur just anywhere in the
   423 text; the fixed correlation with particular command syntax has been
   424 discontinued;
   425 
   426 * Pure: new method 'rules' is particularly well-suited for proof
   427 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   428 but often produces more compact proof terms with less detours;
   429 
   430 * Pure/Provers/classical: simplified integration with pure rule
   431 attributes and methods; the classical "intro?/elim?/dest?"
   432 declarations coincide with the pure ones; the "rule" method no longer
   433 includes classically swapped intros; "intro" and "elim" methods no
   434 longer pick rules from the context; also got rid of ML declarations
   435 AddXIs/AddXEs/AddXDs; all of this has some potential for
   436 INCOMPATIBILITY;
   437 
   438 * Provers/classical: attribute 'swapped' produces classical inversions
   439 of introduction rules;
   440 
   441 * Provers/simplifier: 'simplified' attribute may refer to explicit
   442 rules instead of full simplifier context; 'iff' attribute handles
   443 conditional rules;
   444 
   445 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   446 
   447 * HOL: 'recdef' now fails on unfinished automated proofs, use
   448 "(permissive)" option to recover old behavior;
   449 
   450 * HOL: 'inductive' no longer features separate (collective) attributes
   451 for 'intros' (was found too confusing);
   452 
   453 * HOL: properly declared induction rules less_induct and
   454 wf_induct_rule;
   455 
   456 
   457 *** HOL ***
   458 
   459 * HOL: moved over to sane numeral syntax; the new policy is as
   460 follows:
   461 
   462   - 0 and 1 are polymorphic constants, which are defined on any
   463   numeric type (nat, int, real etc.);
   464 
   465   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   466   binary representation internally;
   467 
   468   - type nat has special constructor Suc, and generally prefers Suc 0
   469   over 1::nat and Suc (Suc 0) over 2::nat;
   470 
   471 This change may cause significant problems of INCOMPATIBILITY; here
   472 are some hints on converting existing sources:
   473 
   474   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   475   entities, so expressions involving "-" (unary or binary minus) need
   476   to be spaced properly;
   477 
   478   - existing occurrences of "1" may need to be constraint "1::nat" or
   479   even replaced by Suc 0; similar for old "2";
   480 
   481   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   482 
   483   - remove all special provisions on numerals in proofs;
   484 
   485 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   486 representation (depends on bin_arith_simps in the default context);
   487 
   488 * HOL: symbolic syntax for x^2 (numeral 2);
   489 
   490 * HOL: the class of all HOL types is now called "type" rather than
   491 "term"; INCOMPATIBILITY, need to adapt references to this type class
   492 in axclass/classes, instance/arities, and (usually rare) occurrences
   493 in typings (of consts etc.); internally the class is called
   494 "HOL.type", ML programs should refer to HOLogic.typeS;
   495 
   496 * HOL/record package improvements:
   497   - new derived operations "fields" to build a partial record section,
   498     "extend" to promote a fixed record to a record scheme, and
   499     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   500     declared as simp by default;
   501   - shared operations ("more", "fields", etc.) now need to be always
   502     qualified) --- potential INCOMPATIBILITY;
   503   - removed "make_scheme" operations (use "make" with "extend") --
   504     INCOMPATIBILITY;
   505   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   506   - provides cases/induct rules for use with corresponding Isar
   507     methods (for concrete records, record schemes, concrete more
   508     parts, and schematic more parts -- in that order);
   509   - internal definitions directly based on a light-weight abstract
   510     theory of product types over typedef rather than datatype;
   511 
   512 * HOL: generic code generator for generating executable ML code from
   513 specifications; specific support for HOL constructs such as inductive
   514 datatypes and sets, as well as recursive functions; can be invoked
   515 via 'generate_code' theory section;
   516 
   517 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   518 
   519 * HOL: consolidated and renamed several theories.  In particular:
   520 	Ord.thy has been absorbed into HOL.thy
   521 	String.thy has been absorbed into List.thy
   522  
   523 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   524 (beware of argument permutation!);
   525 
   526 * HOL: linorder_less_split superseded by linorder_cases;
   527 
   528 * HOL/List: "nodups" renamed to "distinct";
   529 
   530 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   531 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   532   - Ex_def has changed, now need to use some_eq_ex
   533 
   534 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   535 in this (rare) case use:
   536 
   537   delSWrapper "split_all_tac"
   538   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   539 
   540 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   541 MAY FAIL;
   542 
   543 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   544 Isabelle's type classes, ^ on functions and relations has too general
   545 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   546 necessary to attach explicit type constraints;
   547 
   548 * HOL/Relation: the prefix name of the infix "O" has been changed from
   549 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   550 renamed accordingly (eg "compI" -> "rel_compI").
   551 
   552 * HOL: syntax translations now work properly with numerals and records
   553 expressions;
   554 
   555 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   556 of "lam" -- INCOMPATIBILITY;
   557 
   558 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   559 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   560 renamed "Product_Type.unit";
   561 
   562 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   563 
   564 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   565 the "cases" method);
   566 
   567 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   568 Florian Kammüller);
   569 
   570 * HOL/IMP: updated and converted to new-style theory format; several
   571 parts turned into readable document, with proper Isar proof texts and
   572 some explanations (by Gerwin Klein);
   573 
   574 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   575 
   576 * HOL-Hyperreal is now a logic image;
   577 
   578 
   579 *** HOLCF ***
   580 
   581 * Isar: consts/constdefs supports mixfix syntax for continuous
   582 operations;
   583 
   584 * Isar: domain package adapted to new-style theory format, e.g. see
   585 HOLCF/ex/Dnat.thy;
   586 
   587 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   588 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   589 lift.induct_tac, always use UU instead of Undef;
   590 
   591 * HOLCF/IMP: updated and converted to new-style theory;
   592 
   593 
   594 *** ZF ***
   595 
   596 * Isar: proper integration of logic-specific tools and packages,
   597 including theory commands '(co)inductive', '(co)datatype',
   598 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   599 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   600 
   601 * theory Main no longer includes AC; for the Axiom of Choice, base
   602 your theory on Main_ZFC;
   603 
   604 * the integer library now covers quotients and remainders, with many
   605 laws relating division to addition, multiplication, etc.;
   606 
   607 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   608 typeless version of the formalism;
   609 
   610 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   611 format;
   612 
   613 * ZF/Induct: new directory for examples of inductive definitions,
   614 including theory Multiset for multiset orderings; converted to
   615 new-style theory format;
   616 
   617 * ZF: many new theorems about lists, ordinals, etc.;
   618 
   619 
   620 *** General ***
   621 
   622 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   623 variable proof controls level of detail: 0 = no proofs (only oracle
   624 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   625 also ref manual for further ML interfaces;
   626 
   627 * Pure/axclass: removed obsolete ML interface
   628 goal_subclass/goal_arity;
   629 
   630 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   631 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   632 separate tokens, so expressions involving minus need to be spaced
   633 properly;
   634 
   635 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   636 rather than "infixl" or "infixr";
   637 
   638 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   639 sort constraint specifications in type inference; e.g. "x::_::foo"
   640 ensures that the type of "x" is of sort "foo" (but not necessarily a
   641 type variable);
   642 
   643 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   644 control output of nested => (types); the default behavior is
   645 "type_brackets";
   646 
   647 * Pure/syntax: builtin parse translation for "_constify" turns valued
   648 tokens into AST constants;
   649 
   650 * Pure/syntax: prefer later declarations of translations and print
   651 translation functions; potential INCOMPATIBILITY: need to reverse
   652 multiple declarations for same syntax element constant;
   653 
   654 * Pure/show_hyps reset by default (in accordance to existing Isar
   655 practice);
   656 
   657 * Provers/classical: renamed addaltern to addafter, addSaltern to
   658 addSafter;
   659 
   660 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   661 as well;
   662 
   663 * system: tested support for MacOS X; should be able to get Isabelle +
   664 Proof General to work in a plain Terminal after installing Poly/ML
   665 (e.g. from the Isabelle distribution area) and GNU bash alone
   666 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   667 support requires further installations, e.g. from
   668 http://fink.sourceforge.net/);
   669 
   670 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   671 
   672 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   673 of 40 MB), cf. ML_OPTIONS;
   674 
   675 * system: Proof General keywords specification is now part of the
   676 Isabelle distribution (see etc/isar-keywords.el);
   677 
   678 * system: support for persistent Proof General sessions (refrain from
   679 outdating all loaded theories on startup); user may create writable
   680 logic images like this: ``isabelle -q HOL Test'';
   681 
   682 * system: smart selection of Isabelle process versus Isabelle
   683 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   684 run both "isabelle" and "Isabelle" even if file names are badly
   685 damaged (executable inspects the case of the first letter of its own
   686 name); added separate "isabelle-process" and "isabelle-interface";
   687 
   688 * system: refrain from any attempt at filtering input streams; no
   689 longer support ``8bit'' encoding of old isabelle font, instead proper
   690 iso-latin characters may now be used; the related isatools
   691 "symbolinput" and "nonascii" have disappeared as well;
   692 
   693 * system: removed old "xterm" interface (the print modes "xterm" and
   694 "xterm_color" are still available for direct use in a suitable
   695 terminal);
   696 
   697 
   698 
   699 New in Isabelle99-2 (February 2001)
   700 -----------------------------------
   701 
   702 *** Overview of INCOMPATIBILITIES ***
   703 
   704 * HOL: please note that theories in the Library and elsewhere often use the
   705 new-style (Isar) format; to refer to their theorems in an ML script you must
   706 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   707 
   708 * HOL: inductive package no longer splits induction rule aggressively,
   709 but only as far as specified by the introductions given; the old
   710 format may be recovered via ML function complete_split_rule or attribute
   711 'split_rule (complete)';
   712 
   713 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   714 gfp_Tarski to gfp_unfold;
   715 
   716 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   717 
   718 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   719 relation); infix "^^" has been renamed "``"; infix "``" has been
   720 renamed "`"; "univalent" has been renamed "single_valued";
   721 
   722 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   723 operation;
   724 
   725 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   726 
   727 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   728 
   729 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   730 consequence, it is no longer monotonic wrt. the local goal context
   731 (which is now passed through the inductive cases);
   732 
   733 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   734 \<gg> to \<ggreater>;
   735 
   736 
   737 *** Document preparation ***
   738 
   739 * \isabellestyle{NAME} selects version of Isabelle output (currently
   740 available: are "it" for near math-mode best-style output, "sl" for
   741 slanted text style, and "tt" for plain type-writer; if no
   742 \isabellestyle command is given, output is according to slanted
   743 type-writer);
   744 
   745 * support sub/super scripts (for single symbols only), input syntax is
   746 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   747 
   748 * some more standard symbols; see Appendix A of the system manual for
   749 the complete list of symbols defined in isabellesym.sty;
   750 
   751 * improved isabelle style files; more abstract symbol implementation
   752 (should now use \isamath{...} and \isatext{...} in custom symbol
   753 definitions);
   754 
   755 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   756 state; Note that presentation of goal states does not conform to
   757 actual human-readable proof documents.  Please do not include goal
   758 states into document output unless you really know what you are doing!
   759 
   760 * proper indentation of antiquoted output with proportional LaTeX
   761 fonts;
   762 
   763 * no_document ML operator temporarily disables LaTeX document
   764 generation;
   765 
   766 * isatool unsymbolize tunes sources for plain ASCII communication;
   767 
   768 
   769 *** Isar ***
   770 
   771 * Pure: Isar now suffers initial goal statements to contain unbound
   772 schematic variables (this does not conform to actual readable proof
   773 documents, due to unpredictable outcome and non-compositional proof
   774 checking); users who know what they are doing may use schematic goals
   775 for Prolog-style synthesis of proven results;
   776 
   777 * Pure: assumption method (an implicit finishing) now handles actual
   778 rules as well;
   779 
   780 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   781 initial goal, declare "that" only as Pure intro (only for single
   782 steps); the "that" rule assumption may now be involved in implicit
   783 finishing, thus ".." becomes a feasible for trivial obtains;
   784 
   785 * Pure: default proof step now includes 'intro_classes'; thus trivial
   786 instance proofs may be performed by "..";
   787 
   788 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   789 statements as well;
   790 
   791 * Pure: more robust selection of calculational rules;
   792 
   793 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   794 rule (as well as the assumption rule);
   795 
   796 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   797 lemmas, using the graph browser tool;
   798 
   799 * Pure: predict failure of "show" in interactive mode;
   800 
   801 * Pure: 'thms_containing' now takes actual terms as arguments;
   802 
   803 * HOL: improved method 'induct' --- now handles non-atomic goals
   804 (potential INCOMPATIBILITY); tuned error handling;
   805 
   806 * HOL: cases and induct rules now provide explicit hints about the
   807 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   808 any remaining facts are inserted into the goal verbatim;
   809 
   810 * HOL: local contexts (aka cases) may now contain term bindings as
   811 well; the 'cases' and 'induct' methods new provide a ?case binding for
   812 the result to be shown in each case;
   813 
   814 * HOL: added 'recdef_tc' command;
   815 
   816 * isatool convert assists in eliminating legacy ML scripts;
   817 
   818 
   819 *** HOL ***
   820 
   821 * HOL/Library: a collection of generic theories to be used together
   822 with main HOL; the theory loader path already includes this directory
   823 by default; the following existing theories have been moved here:
   824 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   825 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   826 
   827 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   828 modelling and verification task performed in Isabelle/HOL +
   829 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   830 
   831 * HOL/Algebra: special summation operator SUM no longer exists, it has
   832 been replaced by setsum; infix 'assoc' now has priority 50 (like
   833 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   834 'domain', this makes the theory consistent with mathematical
   835 literature;
   836 
   837 * HOL basics: added overloaded operations "inverse" and "divide"
   838 (infix "/"), syntax for generic "abs" operation, generic summation
   839 operator \<Sum>;
   840 
   841 * HOL/typedef: simplified package, provide more useful rules (see also
   842 HOL/subset.thy);
   843 
   844 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   845 now expressed as a proper nested rule (old-style tactic scripts may
   846 require atomize_strip_tac to cope with non-atomic premises);
   847 
   848 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   849 to "split_conv" (old name still available for compatibility);
   850 
   851 * HOL: improved concrete syntax for strings (e.g. allows translation
   852 rules with string literals);
   853 
   854 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   855  and Fleuriot's mechanization of analysis, including the transcendental
   856  functions for the reals;
   857 
   858 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   859 
   860 
   861 *** CTT ***
   862 
   863 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   864 "lam" is displayed as TWO lambda-symbols
   865 
   866 * CTT: theory Main now available, containing everything (that is, Bool
   867 and Arith);
   868 
   869 
   870 *** General ***
   871 
   872 * Pure: the Simplifier has been implemented properly as a derived rule
   873 outside of the actual kernel (at last!); the overall performance
   874 penalty in practical applications is about 50%, while reliability of
   875 the Isabelle inference kernel has been greatly improved;
   876 
   877 * print modes "brackets" and "no_brackets" control output of nested =>
   878 (types) and ==> (props); the default behaviour is "brackets";
   879 
   880 * Provers: fast_tac (and friends) now handle actual object-logic rules
   881 as assumptions as well;
   882 
   883 * system: support Poly/ML 4.0;
   884 
   885 * system: isatool install handles KDE version 1 or 2;
   886 
   887 
   888 
   889 New in Isabelle99-1 (October 2000)
   890 ----------------------------------
   891 
   892 *** Overview of INCOMPATIBILITIES ***
   893 
   894 * HOL: simplification of natural numbers is much changed; to partly
   895 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   896 issue the following ML commands:
   897 
   898   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   899   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   900 
   901 * HOL: simplification no longer dives into case-expressions; this is
   902 controlled by "t.weak_case_cong" for each datatype t;
   903 
   904 * HOL: nat_less_induct renamed to less_induct;
   905 
   906 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   907 fixsome to patch .thy and .ML sources automatically;
   908 
   909   select_equality  -> some_equality
   910   select_eq_Ex     -> some_eq_ex
   911   selectI2EX       -> someI2_ex
   912   selectI2         -> someI2
   913   selectI          -> someI
   914   select1_equality -> some1_equality
   915   Eps_sym_eq       -> some_sym_eq_trivial
   916   Eps_eq           -> some_eq_trivial
   917 
   918 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   919 
   920 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   921 instead);
   922 
   923 * HOL: the recursion equations generated by 'recdef' are now called
   924 f.simps instead of f.rules;
   925 
   926 * HOL: qed_spec_mp now also handles bounded ALL as well;
   927 
   928 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   929 sometimes be needed;
   930 
   931 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   932 
   933 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   934 
   935 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   936 product is now "<*>" instead of "Times"; the lexicographic product is
   937 now "<*lex*>" instead of "**";
   938 
   939 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   940 of main HOL, but was unused); better use HOL's datatype package;
   941 
   942 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   943 the old syntax may be recovered as follows:
   944 
   945   syntax (symbols)
   946     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   947       (infixl "\\<oplus>" 100)
   948 
   949 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   950 
   951 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   952 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   953 internally;
   954 
   955 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   956 changed from A/r to A//r;
   957 
   958 * ZF: new treatment of arithmetic (nat & int) may break some old
   959 proofs;
   960 
   961 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   962 rulify -> rule_format, elimify -> elim_format, ...);
   963 
   964 * Isar/Provers: intro/elim/dest attributes changed; renamed
   965 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   966 should have to change intro!! to intro? only); replaced "delrule" by
   967 "rule del";
   968 
   969 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   970 
   971 * Provers: strengthened force_tac by using new first_best_tac;
   972 
   973 * LaTeX document preparation: several changes of isabelle.sty (see
   974 lib/texinputs);
   975 
   976 
   977 *** Document preparation ***
   978 
   979 * formal comments (text blocks etc.) in new-style theories may now
   980 contain antiquotations of thm/prop/term/typ/text to be presented
   981 according to latex print mode; concrete syntax is like this:
   982 @{term[show_types] "f(x) = a + x"};
   983 
   984 * isatool mkdir provides easy setup of Isabelle session directories,
   985 including proper document sources;
   986 
   987 * generated LaTeX sources are now deleted after successful run
   988 (isatool document -c); may retain a copy somewhere else via -D option
   989 of isatool usedir;
   990 
   991 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   992 style files, achieving self-contained LaTeX sources and simplifying
   993 LaTeX debugging;
   994 
   995 * old-style theories now produce (crude) LaTeX output as well;
   996 
   997 * browser info session directories are now self-contained (may be put
   998 on WWW server seperately); improved graphs of nested sessions; removed
   999 graph for 'all sessions';
  1000 
  1001 * several improvements in isabelle style files; \isabellestyle{it}
  1002 produces fake math mode output; \isamarkupheader is now \section by
  1003 default; see lib/texinputs/isabelle.sty etc.;
  1004 
  1005 
  1006 *** Isar ***
  1007 
  1008 * Isar/Pure: local results and corresponding term bindings are now
  1009 subject to Hindley-Milner polymorphism (similar to ML); this
  1010 accommodates incremental type-inference very nicely;
  1011 
  1012 * Isar/Pure: new derived language element 'obtain' supports
  1013 generalized existence reasoning;
  1014 
  1015 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1016 support accumulation of results, without applying any rules yet;
  1017 useful to collect intermediate results without explicit name
  1018 references, and for use with transitivity rules with more than 2
  1019 premises;
  1020 
  1021 * Isar/Pure: scalable support for case-analysis type proofs: new
  1022 'case' language element refers to local contexts symbolically, as
  1023 produced by certain proof methods; internally, case names are attached
  1024 to theorems as "tags";
  1025 
  1026 * Isar/Pure: theory command 'hide' removes declarations from
  1027 class/type/const name spaces;
  1028 
  1029 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1030 indicate potential overloading;
  1031 
  1032 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1033 
  1034 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1035 "{a,b,c}" instead of {a,b,c};
  1036 
  1037 * Isar/Pure now provides its own version of intro/elim/dest
  1038 attributes; useful for building new logics, but beware of confusion
  1039 with the version in Provers/classical;
  1040 
  1041 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1042 case name 'antecedent';
  1043 
  1044 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1045 to the current context is now done automatically);
  1046 
  1047 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1048 for definining proof methods in ML;
  1049 
  1050 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1051 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1052 most cases, one should have to change intro!! to intro? only);
  1053 replaced "delrule" by "rule del";
  1054 
  1055 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1056 'symmetric' attribute (the latter supercedes [RS sym]);
  1057 
  1058 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1059 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1060 well (including splits);
  1061 
  1062 * Isar/Provers: Simplifier and Classical methods now support all kind
  1063 of modifiers used in the past, including 'cong', 'iff', etc.
  1064 
  1065 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1066 of Simplifier and Classical reasoner);
  1067 
  1068 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1069 now support named cases; major packages (inductive, datatype, primrec,
  1070 recdef) support case names and properly name parameters;
  1071 
  1072 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1073 monotonicity conditions are extracted to be proven at end of
  1074 calculations;
  1075 
  1076 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1077 method anyway;
  1078 
  1079 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1080 split_if split_if_asm; datatype package provides theorems foo.splits =
  1081 foo.split foo.split_asm for each datatype;
  1082 
  1083 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1084 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1085 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1086 use "(cases (simplified))" method in proper proof texts);
  1087 
  1088 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1089 
  1090 * Isar: names of theorems etc. may be natural numbers as well;
  1091 
  1092 * Isar: 'pr' command: optional arguments for goals_limit and
  1093 ProofContext.prems_limit; no longer prints theory contexts, but only
  1094 proof states;
  1095 
  1096 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1097 additional print modes to be specified; e.g. "pr(latex)" will print
  1098 proof state according to the Isabelle LaTeX style;
  1099 
  1100 * Isar: improved support for emulating tactic scripts, including proof
  1101 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1102 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1103 (for HOL datatypes);
  1104 
  1105 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1106 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1107 'proof method scripts' have to be in depth-first order;
  1108 
  1109 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1110 
  1111 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1112 should instead use individual commands for printing items
  1113 (print_commands, print_methods etc.);
  1114 
  1115 * Isar: added 'nothing' --- the empty list of theorems;
  1116 
  1117 
  1118 *** HOL ***
  1119 
  1120 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1121 corresponding virtual machine and a specification of its bytecode
  1122 verifier and a lightweight bytecode verifier, including proofs of
  1123 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1124 Cornelia Pusch (see also the homepage of project Bali at
  1125 http://isabelle.in.tum.de/Bali/);
  1126 
  1127 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1128 Clemens Ballarin;
  1129 
  1130 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1131 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1132 Rasmussen;
  1133 
  1134 * HOL/Lattice: fundamental concepts of lattice theory and order
  1135 structures, including duals, properties of bounds versus algebraic
  1136 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1137 Theorem for complete lattices etc.; may also serve as a demonstration
  1138 for abstract algebraic reasoning using axiomatic type classes, and
  1139 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1140 
  1141 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1142 von Oheimb;
  1143 
  1144 * HOL/IMPP: extension of IMP with local variables and mutually
  1145 recursive procedures, by David von Oheimb;
  1146 
  1147 * HOL/Lambda: converted into new-style theory and document;
  1148 
  1149 * HOL/ex/Multiquote: example of multiple nested quotations and
  1150 anti-quotations -- basically a generalized version of de-Bruijn
  1151 representation; very useful in avoiding lifting of operations;
  1152 
  1153 * HOL/record: added general record equality rule to simpset; fixed
  1154 select-update simplification procedure to handle extended records as
  1155 well; admit "r" as field name;
  1156 
  1157 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1158 other numeric types and also as the identity of groups, rings, etc.;
  1159 
  1160 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1161 Types nat and int belong to this axclass;
  1162 
  1163 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1164    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1165    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1166   two terms #m*u and #n*u are replaced by #(m+n)*u
  1167     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1168   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1169     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1170 
  1171 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1172 powerful prover for predicate logic but knows nothing of clasets; see
  1173 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1174 
  1175 * HOL: new version of "case_tac" subsumes both boolean case split and
  1176 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1177 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1178 
  1179 * HOL: simplification no longer dives into case-expressions: only the
  1180 selector expression is simplified, but not the remaining arms; to
  1181 enable full simplification of case-expressions for datatype t, you may
  1182 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1183 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1184 
  1185 * HOL/recdef: the recursion equations generated by 'recdef' for
  1186 function 'f' are now called f.simps instead of f.rules; if all
  1187 termination conditions are proved automatically, these simplification
  1188 rules are added to the simpset, as in primrec; rules may be named
  1189 individually as well, resulting in a separate list of theorems for
  1190 each equation;
  1191 
  1192 * HOL/While is a new theory that provides a while-combinator. It
  1193 permits the definition of tail-recursive functions without the
  1194 provision of a termination measure. The latter is necessary once the
  1195 invariant proof rule for while is applied.
  1196 
  1197 * HOL: new (overloaded) notation for the set of elements below/above
  1198 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1199 
  1200 * HOL: theorems impI, allI, ballI bound as "strip";
  1201 
  1202 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1203 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1204 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1205 
  1206 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1207 
  1208 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1209 main HOL, but was unused);
  1210 
  1211 * HOL: fewer consts declared as global (e.g. have to refer to
  1212 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1213 
  1214 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1215 in case of overlap with user translations (e.g. judgements over
  1216 tuples); (note that the underlying logical represenation is still
  1217 bogus);
  1218 
  1219 
  1220 *** ZF ***
  1221 
  1222 * ZF: simplification automatically cancels common terms in arithmetic
  1223 expressions over nat and int;
  1224 
  1225 * ZF: new treatment of nat to minimize type-checking: all operators
  1226 coerce their operands to a natural number using the function natify,
  1227 making the algebraic laws unconditional;
  1228 
  1229 * ZF: as above, for int: operators coerce their operands to an integer
  1230 using the function intify;
  1231 
  1232 * ZF: the integer library now contains many of the usual laws for the
  1233 orderings, including $<=, and monotonicity laws for $+ and $*;
  1234 
  1235 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1236 simplification;
  1237 
  1238 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1239 to the simplifier and classical reasoner simultaneously;
  1240 
  1241 
  1242 *** General ***
  1243 
  1244 * Provers: blast_tac now handles actual object-logic rules as
  1245 assumptions; note that auto_tac uses blast_tac internally as well;
  1246 
  1247 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1248 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1249 
  1250 * Provers: delrules now handles destruct rules as well (no longer need
  1251 explicit make_elim);
  1252 
  1253 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1254   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1255 use instead the strong form,
  1256   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1257 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1258 from destruct-rules;
  1259 
  1260 * Provers: Simplifier.easy_setup provides a fast path to basic
  1261 Simplifier setup for new object-logics;
  1262 
  1263 * Pure: AST translation rules no longer require constant head on LHS;
  1264 
  1265 * Pure: improved name spaces: ambiguous output is qualified; support
  1266 for hiding of names;
  1267 
  1268 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1269 XSYMBOL_HOME; no longer need to do manual configuration in most
  1270 situations;
  1271 
  1272 * system: compression of ML heaps images may now be controlled via -c
  1273 option of isabelle and isatool usedir (currently only observed by
  1274 Poly/ML);
  1275 
  1276 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1277 useful for remote X11);
  1278 
  1279 * system: provide TAGS file for Isabelle sources;
  1280 
  1281 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1282 order;
  1283 
  1284 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1285 timing flag supersedes proof_timing and Toplevel.trace;
  1286 
  1287 * ML: new combinators |>> and |>>> for incremental transformations
  1288 with secondary results (e.g. certain theory extensions):
  1289 
  1290 * ML: PureThy.add_defs gets additional argument to indicate potential
  1291 overloading (usually false);
  1292 
  1293 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1294 results;
  1295 
  1296 
  1297 
  1298 New in Isabelle99 (October 1999)
  1299 --------------------------------
  1300 
  1301 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1302 
  1303 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1304 are no longer simplified.  (This allows the simplifier to unfold recursive
  1305 functional programs.)  To restore the old behaviour, declare
  1306 
  1307     Delcongs [if_weak_cong];
  1308 
  1309 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1310 complement;
  1311 
  1312 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1313 
  1314 * HOL/datatype: mutual_induct_tac no longer exists --
  1315   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1316 
  1317 * HOL/typedef: fixed type inference for representing set; type
  1318 arguments now have to occur explicitly on the rhs as type constraints;
  1319 
  1320 * ZF: The con_defs part of an inductive definition may no longer refer
  1321 to constants declared in the same theory;
  1322 
  1323 * HOL, ZF: the function mk_cases, generated by the inductive
  1324 definition package, has lost an argument.  To simplify its result, it
  1325 uses the default simpset instead of a supplied list of theorems.
  1326 
  1327 * HOL/List: the constructors of type list are now Nil and Cons;
  1328 
  1329 * Simplifier: the type of the infix ML functions
  1330         setSSolver addSSolver setSolver addSolver
  1331 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1332 for packaging solvers. A solver is created via
  1333         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1334 where the string argument is only a comment.
  1335 
  1336 
  1337 *** Proof tools ***
  1338 
  1339 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1340 decision procedure for linear arithmetic. Currently it is used for
  1341 types `nat', `int', and `real' in HOL (see below); it can, should and
  1342 will be instantiated for other types and logics as well.
  1343 
  1344 * The simplifier now accepts rewrite rules with flexible heads, eg
  1345      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1346   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1347   matching.
  1348 
  1349 
  1350 *** General ***
  1351 
  1352 * New Isabelle/Isar subsystem provides an alternative to traditional
  1353 tactical theorem proving; together with the ProofGeneral/isar user
  1354 interface it offers an interactive environment for developing human
  1355 readable proof documents (Isar == Intelligible semi-automated
  1356 reasoning); for further information see isatool doc isar-ref,
  1357 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1358 
  1359 * improved and simplified presentation of theories: better HTML markup
  1360 (including colors), graph views in several sizes; isatool usedir now
  1361 provides a proper interface for user theories (via -P option); actual
  1362 document preparation based on (PDF)LaTeX is available as well (for
  1363 new-style theories only); see isatool doc system for more information;
  1364 
  1365 * native support for Proof General, both for classic Isabelle and
  1366 Isabelle/Isar;
  1367 
  1368 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1369 using the graph browser tool;
  1370 
  1371 * Isabelle manuals now also available as PDF;
  1372 
  1373 * theory loader rewritten from scratch (may not be fully
  1374 bug-compatible); old loadpath variable has been replaced by show_path,
  1375 add_path, del_path, reset_path functions; new operations such as
  1376 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1377 isatool doc ref);
  1378 
  1379 * improved isatool install: option -k creates KDE application icon,
  1380 option -p DIR installs standalone binaries;
  1381 
  1382 * added ML_PLATFORM setting (useful for cross-platform installations);
  1383 more robust handling of platform specific ML images for SML/NJ;
  1384 
  1385 * the settings environment is now statically scoped, i.e. it is never
  1386 created again in sub-processes invoked from isabelle, isatool, or
  1387 Isabelle;
  1388 
  1389 * path element specification '~~' refers to '$ISABELLE_HOME';
  1390 
  1391 * in locales, the "assumes" and "defines" parts may be omitted if
  1392 empty;
  1393 
  1394 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1395 long arrows);
  1396 
  1397 * new print_mode "HTML";
  1398 
  1399 * new flag show_tags controls display of tags of theorems (which are
  1400 basically just comments that may be attached by some tools);
  1401 
  1402 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1403 mode and goal output format:
  1404 
  1405 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1406 244c244
  1407 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1408 ---
  1409 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1410 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1411 181c181
  1412 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1413 ---
  1414 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1415 
  1416 * function bind_thms stores lists of theorems (cf. bind_thm);
  1417 
  1418 * new shorthand tactics ftac, eatac, datac, fatac;
  1419 
  1420 * qed (and friends) now accept "" as result name; in that case the
  1421 theorem is not stored, but proper checks and presentation of the
  1422 result still apply;
  1423 
  1424 * theorem database now also indexes constants "Trueprop", "all",
  1425 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1426 
  1427 
  1428 *** HOL ***
  1429 
  1430 ** HOL arithmetic **
  1431 
  1432 * There are now decision procedures for linear arithmetic over nat and
  1433 int:
  1434 
  1435 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1436 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1437 are treated as atomic; subformulae not involving type `nat' or `int'
  1438 are ignored; quantified subformulae are ignored unless they are
  1439 positive universal or negative existential. The tactic has to be
  1440 invoked by hand and can be a little bit slow. In particular, the
  1441 running time is exponential in the number of occurrences of `min' and
  1442 `max', and `-' on `nat'.
  1443 
  1444 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1445 (negated) (in)equalities among the premises and the conclusion into
  1446 account (i.e. no compound formulae) and does not know about `min' and
  1447 `max', and `-' on `nat'. It is fast and is used automatically by the
  1448 simplifier.
  1449 
  1450 NB: At the moment, these decision procedures do not cope with mixed
  1451 nat/int formulae where the two parts interact, such as `m < n ==>
  1452 int(m) < int(n)'.
  1453 
  1454 * HOL/Numeral provides a generic theory of numerals (encoded
  1455 efficiently as bit strings); setup for types nat/int/real is in place;
  1456 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1457 int, existing theories and proof scripts may require a few additional
  1458 type constraints;
  1459 
  1460 * integer division and remainder can now be performed on constant
  1461 arguments;
  1462 
  1463 * many properties of integer multiplication, division and remainder
  1464 are now available;
  1465 
  1466 * An interface to the Stanford Validity Checker (SVC) is available through the
  1467 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1468 are proved automatically.  SVC must be installed separately, and its results
  1469 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1470 invocation of the underlying oracle).  For SVC see
  1471   http://verify.stanford.edu/SVC
  1472 
  1473 * IsaMakefile: the HOL-Real target now builds an actual image;
  1474 
  1475 
  1476 ** HOL misc **
  1477 
  1478 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1479 (in Isabelle/Isar) -- by Gertrud Bauer;
  1480 
  1481 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1482 analysis for assembly languages with subtypes;
  1483 
  1484 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1485 -- avoids syntactic ambiguities and treats state, transition, and
  1486 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1487 changed syntax and (many) tactics;
  1488 
  1489 * HOL/inductive: Now also handles more general introduction rules such
  1490   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1491   theorems are now maintained within the theory (maintained via the
  1492   "mono" attribute);
  1493 
  1494 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1495   (using function types) such as
  1496 
  1497   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1498 
  1499 * HOL/record: record_simproc (part of the default simpset) takes care
  1500 of selectors applied to updated records; record_split_tac is no longer
  1501 part of the default claset; update_defs may now be removed from the
  1502 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1503 
  1504   claset_ref () := claset() addSWrapper record_split_wrapper;
  1505   Delsimprocs [record_simproc]
  1506 
  1507 * HOL/typedef: fixed type inference for representing set; type
  1508 arguments now have to occur explicitly on the rhs as type constraints;
  1509 
  1510 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1511 names rather than an ML expression;
  1512 
  1513 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1514 supplied later.  Program schemes can be defined, such as
  1515     "While B C s = (if B s then While B C (C s) else s)"
  1516 where the well-founded relation can be chosen after B and C have been given.
  1517 
  1518 * HOL/List: the constructors of type list are now Nil and Cons;
  1519 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1520 course, ML tools referring to List.list.op # etc. have to be adapted;
  1521 
  1522 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1523 disabled by default; run isabelle with option -m HOL to get back to
  1524 the original Gordon/HOL-style output;
  1525 
  1526 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1527 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1528 
  1529 * HOL basic syntax simplified (more orthogonal): all variants of
  1530 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1531 Eps operator is provided as well: "SOME x. P[x]";
  1532 
  1533 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1534 
  1535 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1536 thus available for user theories;
  1537 
  1538 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1539 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1540 time;
  1541 
  1542 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1543 several times and then mp;
  1544 
  1545 
  1546 *** LK ***
  1547 
  1548 * the notation <<...>> is now available as a notation for sequences of
  1549 formulas;
  1550 
  1551 * the simplifier is now installed
  1552 
  1553 * the axiom system has been generalized (thanks to Soren Heilmann)
  1554 
  1555 * the classical reasoner now has a default rule database
  1556 
  1557 
  1558 *** ZF ***
  1559 
  1560 * new primrec section allows primitive recursive functions to be given
  1561 directly (as in HOL) over datatypes and the natural numbers;
  1562 
  1563 * new tactics induct_tac and exhaust_tac for induction (or case
  1564 analysis) over datatypes and the natural numbers;
  1565 
  1566 * the datatype declaration of type T now defines the recursor T_rec;
  1567 
  1568 * simplification automatically does freeness reasoning for datatype
  1569 constructors;
  1570 
  1571 * automatic type-inference, with AddTCs command to insert new
  1572 type-checking rules;
  1573 
  1574 * datatype introduction rules are now added as Safe Introduction rules
  1575 to the claset;
  1576 
  1577 * the syntax "if P then x else y" is now available in addition to
  1578 if(P,x,y);
  1579 
  1580 
  1581 *** Internal programming interfaces ***
  1582 
  1583 * tuned simplifier trace output; new flag debug_simp;
  1584 
  1585 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1586 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1587 
  1588 * AxClass.axclass_tac lost the theory argument;
  1589 
  1590 * tuned current_goals_markers semantics: begin / end goal avoids
  1591 printing empty lines;
  1592 
  1593 * removed prs and prs_fn hook, which was broken because it did not
  1594 include \n in its semantics, forcing writeln to add one
  1595 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1596 string -> unit if you really want to output text without newline;
  1597 
  1598 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1599 plain output, interface builders may have to enable 'isabelle_font'
  1600 mode to get Isabelle font glyphs as before;
  1601 
  1602 * refined token_translation interface; INCOMPATIBILITY: output length
  1603 now of type real instead of int;
  1604 
  1605 * theory loader actions may be traced via new ThyInfo.add_hook
  1606 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1607 your own database of information attached to *whole* theories -- as
  1608 opposed to intra-theory data slots offered via TheoryDataFun;
  1609 
  1610 * proper handling of dangling sort hypotheses (at last!);
  1611 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1612 extra sort hypotheses that can be witnessed from the type signature;
  1613 the force_strip_shyps flag is gone, any remaining shyps are simply
  1614 left in the theorem (with a warning issued by strip_shyps_warning);
  1615 
  1616 
  1617 
  1618 New in Isabelle98-1 (October 1998)
  1619 ----------------------------------
  1620 
  1621 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1622 
  1623 * several changes of automated proof tools;
  1624 
  1625 * HOL: major changes to the inductive and datatype packages, including
  1626 some minor incompatibilities of theory syntax;
  1627 
  1628 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1629 called `inj_on';
  1630 
  1631 * HOL: removed duplicate thms in Arith:
  1632   less_imp_add_less  should be replaced by  trans_less_add1
  1633   le_imp_add_le      should be replaced by  trans_le_add1
  1634 
  1635 * HOL: unary minus is now overloaded (new type constraints may be
  1636 required);
  1637 
  1638 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1639 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1640 now taken as an integer constant.
  1641 
  1642 * Pure: ML function 'theory_of' renamed to 'theory';
  1643 
  1644 
  1645 *** Proof tools ***
  1646 
  1647 * Simplifier:
  1648   1. Asm_full_simp_tac is now more aggressive.
  1649      1. It will sometimes reorient premises if that increases their power to
  1650         simplify.
  1651      2. It does no longer proceed strictly from left to right but may also
  1652         rotate premises to achieve further simplification.
  1653      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1654      old Asm_full_simp_tac in that it does not rotate premises.
  1655   2. The simplifier now knows a little bit about nat-arithmetic.
  1656 
  1657 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1658 allows for selected deletion of wrappers, by introduction of names for
  1659 wrapper functionals.  This implies that addbefore, addSbefore,
  1660 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1661 and that adding two tactics with the same name overwrites the first
  1662 one (emitting a warning).
  1663   type wrapper = (int -> tactic) -> (int -> tactic)
  1664   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1665   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1666   delWrapper, delSWrapper: claset *  string            -> claset
  1667   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1668 
  1669 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1670 semantics; addbefore now affects only the unsafe part of step_tac
  1671 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1672 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1673 by Force_tac;
  1674 
  1675 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1676 compWrapper; added safe wrapper (and access functions for it);
  1677 
  1678 * HOL/split_all_tac is now much faster and fails if there is nothing
  1679 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1680 and the names of the automatically generated variables have changed.
  1681 split_all_tac has moved within claset() from unsafe wrappers to safe
  1682 wrappers, which means that !!-bound variables are split much more
  1683 aggressively, and safe_tac and clarify_tac now split such variables.
  1684 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1685 Note: the same holds for record_split_tac, which does the job of
  1686 split_all_tac for record fields.
  1687 
  1688 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1689 permanently to the default simpset using Addsplits just like
  1690 Addsimps. They can be removed via Delsplits just like
  1691 Delsimps. Lower-case versions are also available.
  1692 
  1693 * HOL/Simplifier: The rule split_if is now part of the default
  1694 simpset. This means that the simplifier will eliminate all occurrences
  1695 of if-then-else in the conclusion of a goal. To prevent this, you can
  1696 either remove split_if completely from the default simpset by
  1697 `Delsplits [split_if]' or remove it in a specific call of the
  1698 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1699 other case splitting rules to/from the default simpset: every datatype
  1700 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1701 t is the name of the datatype).
  1702 
  1703 * Classical reasoner / Simplifier combination: new force_tac (and
  1704 derivatives Force_tac, force) combines rewriting and classical
  1705 reasoning (and whatever other tools) similarly to auto_tac, but is
  1706 aimed to solve the given subgoal completely.
  1707 
  1708 
  1709 *** General ***
  1710 
  1711 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1712 and `goalw': the theory is no longer needed as an explicit argument -
  1713 the current theory context is used; assumptions are no longer returned
  1714 at the ML-level unless one of them starts with ==> or !!; it is
  1715 recommended to convert to these new commands using isatool fixgoal
  1716 (backup your sources first!);
  1717 
  1718 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1719 the current theory context, and 'theory' to lookup stored theories;
  1720 
  1721 * new theory section 'locale' for declaring constants, assumptions and
  1722 definitions that have local scope;
  1723 
  1724 * new theory section 'nonterminals' for purely syntactic types;
  1725 
  1726 * new theory section 'setup' for generic ML setup functions
  1727 (e.g. package initialization);
  1728 
  1729 * the distribution now includes Isabelle icons: see
  1730 lib/logo/isabelle-{small,tiny}.xpm;
  1731 
  1732 * isatool install - install binaries with absolute references to
  1733 ISABELLE_HOME/bin;
  1734 
  1735 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1736 
  1737 * print mode 'emacs' reserved for Isamode;
  1738 
  1739 * support multiple print (ast) translations per constant name;
  1740 
  1741 * theorems involving oracles are now printed with a suffixed [!];
  1742 
  1743 
  1744 *** HOL ***
  1745 
  1746 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1747 
  1748 * HOL/inductive package reorganized and improved: now supports mutual
  1749 definitions such as
  1750 
  1751   inductive EVEN ODD
  1752     intrs
  1753       null "0 : EVEN"
  1754       oddI "n : EVEN ==> Suc n : ODD"
  1755       evenI "n : ODD ==> Suc n : EVEN"
  1756 
  1757 new theorem list "elims" contains an elimination rule for each of the
  1758 recursive sets; inductive definitions now handle disjunctive premises
  1759 correctly (also ZF);
  1760 
  1761 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1762 "mutual_induct" no longer exists - the induction rule is always
  1763 contained in "induct";
  1764 
  1765 
  1766 * HOL/datatype package re-implemented and greatly improved: now
  1767 supports mutually recursive datatypes such as
  1768 
  1769   datatype
  1770     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1771             | SUM ('a aexp) ('a aexp)
  1772             | DIFF ('a aexp) ('a aexp)
  1773             | NUM 'a
  1774   and
  1775     'a bexp = LESS ('a aexp) ('a aexp)
  1776             | AND ('a bexp) ('a bexp)
  1777             | OR ('a bexp) ('a bexp)
  1778 
  1779 as well as indirectly recursive datatypes such as
  1780 
  1781   datatype
  1782     ('a, 'b) term = Var 'a
  1783                   | App 'b ((('a, 'b) term) list)
  1784 
  1785 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1786 induction on mutually / indirectly recursive datatypes.
  1787 
  1788 Primrec equations are now stored in theory and can be accessed via
  1789 <function_name>.simps.
  1790 
  1791 INCOMPATIBILITIES:
  1792 
  1793   - Theories using datatypes must now have theory Datatype as an
  1794     ancestor.
  1795   - The specific <typename>.induct_tac no longer exists - use the
  1796     generic induct_tac instead.
  1797   - natE has been renamed to nat.exhaust - use exhaust_tac
  1798     instead of res_inst_tac ... natE. Note that the variable
  1799     names in nat.exhaust differ from the names in natE, this
  1800     may cause some "fragile" proofs to fail.
  1801   - The theorems split_<typename>_case and split_<typename>_case_asm
  1802     have been renamed to <typename>.split and <typename>.split_asm.
  1803   - Since default sorts of type variables are now handled correctly,
  1804     some datatype definitions may have to be annotated with explicit
  1805     sort constraints.
  1806   - Primrec definitions no longer require function name and type
  1807     of recursive argument.
  1808 
  1809 Consider using isatool fixdatatype to adapt your theories and proof
  1810 scripts to the new package (backup your sources first!).
  1811 
  1812 
  1813 * HOL/record package: considerably improved implementation; now
  1814 includes concrete syntax for record types, terms, updates; theorems
  1815 for surjective pairing and splitting !!-bound record variables; proof
  1816 support is as follows:
  1817 
  1818   1) standard conversions (selectors or updates applied to record
  1819 constructor terms) are part of the standard simpset;
  1820 
  1821   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1822 made part of standard simpset and claset via addIffs;
  1823 
  1824   3) a tactic for record field splitting (record_split_tac) is part of
  1825 the standard claset (addSWrapper);
  1826 
  1827 To get a better idea about these rules you may retrieve them via
  1828 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1829 the name of your record type.
  1830 
  1831 The split tactic 3) conceptually simplifies by the following rule:
  1832 
  1833   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1834 
  1835 Thus any record variable that is bound by meta-all will automatically
  1836 blow up into some record constructor term, consequently the
  1837 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1838 solve record problems automatically.
  1839 
  1840 
  1841 * reorganized the main HOL image: HOL/Integ and String loaded by
  1842 default; theory Main includes everything;
  1843 
  1844 * automatic simplification of integer sums and comparisons, using cancellation;
  1845 
  1846 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1847 
  1848 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1849 
  1850 * many new identities for unions, intersections, set difference, etc.;
  1851 
  1852 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1853 called split_if, split_split, split_sum_case and split_nat_case (to go
  1854 with add/delsplits);
  1855 
  1856 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1857 (?x::unit) = (); this is made part of the default simpset, which COULD
  1858 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1859 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1860 unit_abs_eta_conv is added in order to counter the effect of
  1861 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1862 %u.f();
  1863 
  1864 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1865 makes more sense);
  1866 
  1867 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1868   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1869   disjointness reasoning but breaking a few old proofs.
  1870 
  1871 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1872 to 'converse' from 'inverse' (for compatibility with ZF and some
  1873 literature);
  1874 
  1875 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1876 the well-founded relation;
  1877 
  1878 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1879     Compl A.  The "Compl" syntax remains available as input syntax for this
  1880     release ONLY.
  1881 
  1882 * HOL/Update: new theory of function updates:
  1883     f(a:=b) == %x. if x=a then b else f x
  1884 may also be iterated as in f(a:=b,c:=d,...);
  1885 
  1886 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1887 
  1888 * HOL/List:
  1889   - new function list_update written xs[i:=v] that updates the i-th
  1890     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1891   - new function `upt' written [i..j(] which generates the list
  1892     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1893     bound write [i..j], which is a shorthand for [i..j+1(].
  1894   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1895 
  1896 * HOL/Arith:
  1897   - removed 'pred' (predecessor) function;
  1898   - generalized some theorems about n-1;
  1899   - many new laws about "div" and "mod";
  1900   - new laws about greatest common divisors (see theory ex/Primes);
  1901 
  1902 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1903 instead of "inverse";
  1904 
  1905 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1906   of the multiset ordering;
  1907 
  1908 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1909   (not included by default);
  1910 
  1911 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1912 
  1913 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1914   programs, i.e. different program variables may have different types.
  1915 
  1916 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1917   [previously, this check worked only if the rewrite rule was unconditional]
  1918   Now rew can involve either definitions or equalities (either == or =).
  1919 
  1920 
  1921 *** ZF ***
  1922 
  1923 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1924   only the theorems proved on ZF.ML;
  1925 
  1926 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1927   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1928   disjointness reasoning but breaking a few old proofs.
  1929 
  1930 * ZF/Update: new theory of function updates
  1931     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1932   may also be iterated as in f(a:=b,c:=d,...);
  1933 
  1934 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1935 
  1936 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1937   [previously, this check worked only if the rewrite rule was unconditional]
  1938   Now rew can involve either definitions or equalities (either == or =).
  1939 
  1940 * case_tac provided for compatibility with HOL
  1941     (like the old excluded_middle_tac, but with subgoals swapped)
  1942 
  1943 
  1944 *** Internal programming interfaces ***
  1945 
  1946 * Pure: several new basic modules made available for general use, see
  1947 also src/Pure/README;
  1948 
  1949 * improved the theory data mechanism to support encapsulation (data
  1950 kind name replaced by private Object.kind, acting as authorization
  1951 key); new type-safe user interface via functor TheoryDataFun; generic
  1952 print_data function becomes basically useless;
  1953 
  1954 * removed global_names compatibility flag -- all theory declarations
  1955 are qualified by default;
  1956 
  1957 * module Pure/Syntax now offers quote / antiquote translation
  1958 functions (useful for Hoare logic etc. with implicit dependencies);
  1959 see HOL/ex/Antiquote for an example use;
  1960 
  1961 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1962 cterm -> thm;
  1963 
  1964 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1965 subgoal;
  1966 
  1967 * Display.print_goals function moved to Locale.print_goals;
  1968 
  1969 * standard print function for goals supports current_goals_markers
  1970 variable for marking begin of proof, end of proof, start of goal; the
  1971 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1972 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1973 for example;
  1974 
  1975 
  1976 
  1977 New in Isabelle98 (January 1998)
  1978 --------------------------------
  1979 
  1980 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1981 
  1982 * changed lexical syntax of terms / types: dots made part of long
  1983 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1984 
  1985 * simpset (and claset) reference variable replaced by functions
  1986 simpset / simpset_ref;
  1987 
  1988 * no longer supports theory aliases (via merge) and non-trivial
  1989 implicit merge of thms' signatures;
  1990 
  1991 * most internal names of constants changed due to qualified names;
  1992 
  1993 * changed Pure/Sequence interface (see Pure/seq.ML);
  1994 
  1995 
  1996 *** General Changes ***
  1997 
  1998 * hierachically structured name spaces (for consts, types, axms, thms
  1999 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2000 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2001 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2002 long_names for fully qualified output names; NOTE: ML programs
  2003 (special tactics, packages etc.) referring to internal names may have
  2004 to be adapted to cope with fully qualified names; in case of severe
  2005 backward campatibility problems try setting 'global_names' at compile
  2006 time to have enrything declared within a flat name space; one may also
  2007 fine tune name declarations in theories via the 'global' and 'local'
  2008 section;
  2009 
  2010 * reimplemented the implicit simpset and claset using the new anytype
  2011 data filed in signatures; references simpset:simpset ref etc. are
  2012 replaced by functions simpset:unit->simpset and
  2013 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2014 to patch your ML files accordingly;
  2015 
  2016 * HTML output now includes theory graph data for display with Java
  2017 applet or isatool browser; data generated automatically via isatool
  2018 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2019 
  2020 * defs may now be conditional; improved rewrite_goals_tac to handle
  2021 conditional equations;
  2022 
  2023 * defs now admits additional type arguments, using TYPE('a) syntax;
  2024 
  2025 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2026 creates a new theory node; implicit merge of thms' signatures is
  2027 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2028 transfer:theory->thm->thm in (rare) cases;
  2029 
  2030 * improved handling of draft signatures / theories; draft thms (and
  2031 ctyps, cterms) are automatically promoted to real ones;
  2032 
  2033 * slightly changed interfaces for oracles: admit many per theory, named
  2034 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2035 
  2036 * print_goals: optional output of const types (set show_consts and
  2037 show_types);
  2038 
  2039 * improved output of warnings (###) and errors (***);
  2040 
  2041 * subgoal_tac displays a warning if the new subgoal has type variables;
  2042 
  2043 * removed old README and Makefiles;
  2044 
  2045 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2046 
  2047 * removed obsolete init_pps and init_database;
  2048 
  2049 * deleted the obsolete tactical STATE, which was declared by
  2050     fun STATE tacfun st = tacfun st st;
  2051 
  2052 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2053 (which abbreviates $HOME);
  2054 
  2055 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2056 use isatool fixseq to adapt your ML programs (this works for fully
  2057 qualified references to the Sequence structure only!);
  2058 
  2059 * use_thy no longer requires writable current directory; it always
  2060 reloads .ML *and* .thy file, if either one is out of date;
  2061 
  2062 
  2063 *** Classical Reasoner ***
  2064 
  2065 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2066 tactics that use classical reasoning to simplify a subgoal without
  2067 splitting it into several subgoals;
  2068 
  2069 * Safe_tac: like safe_tac but uses the default claset;
  2070 
  2071 
  2072 *** Simplifier ***
  2073 
  2074 * added simplification meta rules:
  2075     (asm_)(full_)simplify: simpset -> thm -> thm;
  2076 
  2077 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2078 logics (again);
  2079 
  2080 * added prems argument to simplification procedures;
  2081 
  2082 * HOL, FOL, ZF: added infix function `addsplits':
  2083   instead of `<simpset> setloop (split_tac <thms>)'
  2084   you can simply write `<simpset> addsplits <thms>'
  2085 
  2086 
  2087 *** Syntax ***
  2088 
  2089 * TYPE('a) syntax for type reflection terms;
  2090 
  2091 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2092 
  2093 * pretty printer: changed order of mixfix annotation preference (again!);
  2094 
  2095 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2096 
  2097 
  2098 *** HOL ***
  2099 
  2100 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2101   with `addloop' of the simplifier to faciliate case splitting in premises.
  2102 
  2103 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2104 
  2105 * HOL/Auth: new protocol proofs including some for the Internet
  2106   protocol TLS;
  2107 
  2108 * HOL/Map: new theory of `maps' a la VDM;
  2109 
  2110 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2111 cancelling out common nat summands from =, <, <= (in)equalities, or
  2112 differences; simplification procedures nat_cancel_factor for
  2113 cancelling common factor from =, <, <= (in)equalities over natural
  2114 sums; nat_cancel contains both kinds of procedures, it is installed by
  2115 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2116 
  2117 * HOL/simplifier: terms of the form
  2118   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2119   are rewritten to
  2120   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2121   and those of the form
  2122   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2123   are rewritten to
  2124   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2125 
  2126 * HOL/datatype
  2127   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2128 
  2129   P(t_case f1 ... fn x) =
  2130      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2131         ...
  2132        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2133      )
  2134 
  2135   and a theorem `split_t_case_asm' of the form
  2136 
  2137   P(t_case f1 ... fn x) =
  2138     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2139         ...
  2140        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2141      )
  2142   which can be added to a simpset via `addsplits'. The existing theorems
  2143   expand_list_case and expand_option_case have been renamed to
  2144   split_list_case and split_option_case.
  2145 
  2146 * HOL/Arithmetic:
  2147   - `pred n' is automatically converted to `n-1'.
  2148     Users are strongly encouraged not to use `pred' any longer,
  2149     because it will disappear altogether at some point.
  2150   - Users are strongly encouraged to write "0 < n" rather than
  2151     "n ~= 0". Theorems and proof tools have been modified towards this
  2152     `standard'.
  2153 
  2154 * HOL/Lists:
  2155   the function "set_of_list" has been renamed "set" (and its theorems too);
  2156   the function "nth" now takes its arguments in the reverse order and
  2157   has acquired the infix notation "!" as in "xs!n".
  2158 
  2159 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2160 
  2161 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2162   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2163 
  2164 * HOL/record: extensible records with schematic structural subtyping
  2165 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2166 still lacks various theorems and concrete record syntax;
  2167 
  2168 
  2169 *** HOLCF ***
  2170 
  2171 * removed "axioms" and "generated by" sections;
  2172 
  2173 * replaced "ops" section by extended "consts" section, which is capable of
  2174   handling the continuous function space "->" directly;
  2175 
  2176 * domain package:
  2177   . proves theorems immediately and stores them in the theory,
  2178   . creates hierachical name space,
  2179   . now uses normal mixfix annotations (instead of cinfix...),
  2180   . minor changes to some names and values (for consistency),
  2181   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2182   . separator between mutual domain defs: changed "," to "and",
  2183   . improved handling of sort constraints;  now they have to
  2184     appear on the left-hand side of the equations only;
  2185 
  2186 * fixed LAM <x,y,zs>.b syntax;
  2187 
  2188 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2189 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2190 
  2191 
  2192 *** FOL and ZF ***
  2193 
  2194 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2195   with `addloop' of the simplifier to faciliate case splitting in premises.
  2196 
  2197 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2198 in HOL, they strip ALL and --> from proved theorems;
  2199 
  2200 
  2201 
  2202 New in Isabelle94-8 (May 1997)
  2203 ------------------------------
  2204 
  2205 *** General Changes ***
  2206 
  2207 * new utilities to build / run / maintain Isabelle etc. (in parts
  2208 still somewhat experimental); old Makefiles etc. still functional;
  2209 
  2210 * new 'Isabelle System Manual';
  2211 
  2212 * INSTALL text, together with ./configure and ./build scripts;
  2213 
  2214 * reimplemented type inference for greater efficiency, better error
  2215 messages and clean internal interface;
  2216 
  2217 * prlim command for dealing with lots of subgoals (an easier way of
  2218 setting goals_limit);
  2219 
  2220 
  2221 *** Syntax ***
  2222 
  2223 * supports alternative (named) syntax tables (parser and pretty
  2224 printer); internal interface is provided by add_modesyntax(_i);
  2225 
  2226 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2227 be used in conjunction with the Isabelle symbol font; uses the
  2228 "symbols" syntax table;
  2229 
  2230 * added token_translation interface (may translate name tokens in
  2231 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2232 the current print_mode); IMPORTANT: user print translation functions
  2233 are responsible for marking newly introduced bounds
  2234 (Syntax.mark_boundT);
  2235 
  2236 * token translations for modes "xterm" and "xterm_color" that display
  2237 names in bold, underline etc. or colors (which requires a color
  2238 version of xterm);
  2239 
  2240 * infixes may now be declared with names independent of their syntax;
  2241 
  2242 * added typed_print_translation (like print_translation, but may
  2243 access type of constant);
  2244 
  2245 
  2246 *** Classical Reasoner ***
  2247 
  2248 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2249 some limitations.  Blast_tac...
  2250   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2251   + ignores elimination rules that don't have the correct format
  2252         (the conclusion MUST be a formula variable)
  2253   + ignores types, which can make HOL proofs fail
  2254   + rules must not require higher-order unification, e.g. apply_type in ZF
  2255     [message "Function Var's argument not a bound variable" relates to this]
  2256   + its proof strategy is more general but can actually be slower
  2257 
  2258 * substitution with equality assumptions no longer permutes other
  2259 assumptions;
  2260 
  2261 * minor changes in semantics of addafter (now called addaltern); renamed
  2262 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2263 (and access functions for it);
  2264 
  2265 * improved combination of classical reasoner and simplifier:
  2266   + functions for handling clasimpsets
  2267   + improvement of addss: now the simplifier is called _after_ the
  2268     safe steps.
  2269   + safe variant of addss called addSss: uses safe simplifications
  2270     _during_ the safe steps. It is more complete as it allows multiple
  2271     instantiations of unknowns (e.g. with slow_tac).
  2272 
  2273 *** Simplifier ***
  2274 
  2275 * added interface for simplification procedures (functions that
  2276 produce *proven* rewrite rules on the fly, depending on current
  2277 redex);
  2278 
  2279 * ordering on terms as parameter (used for ordered rewriting);
  2280 
  2281 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2282 
  2283 * the solver is now split into a safe and an unsafe part.
  2284 This should be invisible for the normal user, except that the
  2285 functions setsolver and addsolver have been renamed to setSolver and
  2286 addSolver; added safe_asm_full_simp_tac;
  2287 
  2288 
  2289 *** HOL ***
  2290 
  2291 * a generic induction tactic `induct_tac' which works for all datatypes and
  2292 also for type `nat';
  2293 
  2294 * a generic case distinction tactic `exhaust_tac' which works for all
  2295 datatypes and also for type `nat';
  2296 
  2297 * each datatype comes with a function `size';
  2298 
  2299 * patterns in case expressions allow tuple patterns as arguments to
  2300 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2301 
  2302 * primrec now also works with type nat;
  2303 
  2304 * recdef: a new declaration form, allows general recursive functions to be
  2305 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2306 
  2307 * the constant for negation has been renamed from "not" to "Not" to
  2308 harmonize with FOL, ZF, LK, etc.;
  2309 
  2310 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2311 infinite lists;
  2312 
  2313 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2314 
  2315 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2316 problems in commutative rings, using axiomatic type classes for + and *;
  2317 
  2318 * more examples in HOL/MiniML and HOL/Auth;
  2319 
  2320 * more default rewrite rules for quantifiers, union/intersection;
  2321 
  2322 * a new constant `arbitrary == @x.False';
  2323 
  2324 * HOLCF/IOA replaces old HOL/IOA;
  2325 
  2326 * HOLCF changes: derived all rules and arities
  2327   + axiomatic type classes instead of classes
  2328   + typedef instead of faking type definitions
  2329   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2330   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2331   + eliminated the types void, one, tr
  2332   + use unit lift and bool lift (with translations) instead of one and tr
  2333   + eliminated blift from Lift3.thy (use Def instead of blift)
  2334   all eliminated rules are derived as theorems --> no visible changes ;
  2335 
  2336 
  2337 *** ZF ***
  2338 
  2339 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2340 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2341 as ZF_cs addSIs [equalityI];
  2342 
  2343 
  2344 
  2345 New in Isabelle94-7 (November 96)
  2346 ---------------------------------
  2347 
  2348 * allowing negative levels (as offsets) in prlev and choplev;
  2349 
  2350 * super-linear speedup for large simplifications;
  2351 
  2352 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2353 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2354 FAIL); can suppress it using the command Delsimps (ex_simps @
  2355 all_simps); De Morgan laws are also now included, by default;
  2356 
  2357 * improved printing of ==>  :  ~:
  2358 
  2359 * new object-logic "Sequents" adds linear logic, while replacing LK
  2360 and Modal (thanks to Sara Kalvala);
  2361 
  2362 * HOL/Auth: correctness proofs for authentication protocols;
  2363 
  2364 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2365 examples on HOL/Auth);
  2366 
  2367 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2368 the rewriter and classical reasoner simultaneously;
  2369 
  2370 * function uresult no longer returns theorems in "standard" format;
  2371 regain previous version by: val uresult = standard o uresult;
  2372 
  2373 
  2374 
  2375 New in Isabelle94-6
  2376 -------------------
  2377 
  2378 * oracles -- these establish an interface between Isabelle and trusted
  2379 external reasoners, which may deliver results as theorems;
  2380 
  2381 * proof objects (in particular record all uses of oracles);
  2382 
  2383 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2384 
  2385 * "constdefs" section in theory files;
  2386 
  2387 * "primrec" section (HOL) no longer requires names;
  2388 
  2389 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2390 
  2391 
  2392 
  2393 New in Isabelle94-5
  2394 -------------------
  2395 
  2396 * reduced space requirements;
  2397 
  2398 * automatic HTML generation from theories;
  2399 
  2400 * theory files no longer require "..." (quotes) around most types;
  2401 
  2402 * new examples, including two proofs of the Church-Rosser theorem;
  2403 
  2404 * non-curried (1994) version of HOL is no longer distributed;
  2405 
  2406 
  2407 
  2408 New in Isabelle94-4
  2409 -------------------
  2410 
  2411 * greatly reduced space requirements;
  2412 
  2413 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2414 
  2415 * searchable theorem database (see the section "Retrieving theorems" on
  2416 page 8 of the Reference Manual);
  2417 
  2418 * new examples, including Grabczewski's monumental case study of the
  2419 Axiom of Choice;
  2420 
  2421 * The previous version of HOL renamed to Old_HOL;
  2422 
  2423 * The new version of HOL (previously called CHOL) uses a curried syntax
  2424 for functions.  Application looks like f a b instead of f(a,b);
  2425 
  2426 * Mutually recursive inductive definitions finally work in HOL;
  2427 
  2428 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2429 translates to the operator "split";
  2430 
  2431 
  2432 
  2433 New in Isabelle94-3
  2434 -------------------
  2435 
  2436 * new infix operator, addss, allowing the classical reasoner to
  2437 perform simplification at each step of its search.  Example:
  2438         fast_tac (cs addss ss)
  2439 
  2440 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2441 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2442 look like (a,b) instead of <a,b>;
  2443 
  2444 * PLEASE NOTE: CHOL will eventually replace HOL!
  2445 
  2446 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2447 It translates to the operator "split".  A new theory of integers is available;
  2448 
  2449 * In ZF, integer numerals now denote two's-complement binary integers.
  2450 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2451 
  2452 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2453 of the Axiom of Choice;
  2454 
  2455 
  2456 
  2457 New in Isabelle94-2
  2458 -------------------
  2459 
  2460 * Significantly faster resolution;
  2461 
  2462 * the different sections in a .thy file can now be mixed and repeated
  2463 freely;
  2464 
  2465 * Database of theorems for FOL, HOL and ZF.  New
  2466 commands including qed, qed_goal and bind_thm store theorems in the database.
  2467 
  2468 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2469 a given theory (thms_of), or find out what theory a theorem was proved in
  2470 (theory_of_thm);
  2471 
  2472 * Bugs fixed in the inductive definition and datatype packages;
  2473 
  2474 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2475 and HOL_dup_cs obsolete;
  2476 
  2477 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2478 have been removed;
  2479 
  2480 * Simpler definition of function space in ZF;
  2481 
  2482 * new results about cardinal and ordinal arithmetic in ZF;
  2483 
  2484 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2485 types;
  2486 
  2487 
  2488 $Id$