NEWS
author kleing
Wed Oct 15 01:58:41 2003 +0200 (2003-10-15)
changeset 14233 f6b6b2c55141
parent 14224 442c097c1437
child 14234 9590df3c5f2a
permissions -rw-r--r--
allow \<^sub> in identifiers
     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: single letter subscripts (\<^sub>l) are now allowed in identifiers.
    21   Similar to greek letters \<^sub> is now considered a normal letter. 
    22 	For multiple letter subscripts repeat \<^sub> like this: i\<^sub>1\<^sub>2. 
    23 
    24 * Pure: Using the functions Theory.add_finals or Theory.add_finals_i
    25   or the new Isar command "finalconsts", it is now possible to
    26   make constants "final", thereby ensuring that they are not defined
    27   later.  Useful for constants whose behaviour is fixed axiomatically
    28   rather than definitionally, such as the meta-logic connectives.
    29 
    30 *** Isar ***
    31 
    32 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    33   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    34     locales are no longer forced to write Isar proof scripts.
    35     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    36     emulations.
    37   - INCOMPATIBILITY: names of variables to be instantiated may no
    38     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    39     This is consistent with the instantiation attribute "where".
    40 
    41 * Locales:
    42   - Goal statements involving the context element "includes" no longer
    43     generate theorems with internal delta predicates (those ending on
    44     "_axioms") in the premise.
    45     Resolve particular premise with <locale>.intro to obtain old form.
    46   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    47     specification and "includes" elements in goal statement.
    48 
    49 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    50   (Isar) contexts.
    51 
    52 *** HOL ***
    53 
    54 * 'specification' command added, allowing for definition by
    55   specification.  There is also an 'ax_specification' command that
    56   introduces the new constants axiomatically.
    57 
    58 * SET-Protocol: formalization and verification of the SET protocol suite;
    59 
    60 
    61 New in Isabelle2003 (May 2003)
    62 --------------------------------
    63 
    64 *** General ***
    65 
    66 * Provers/simplifier:
    67 
    68   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    69     Assumptions are now subject to complete mutual simplification,
    70     not just from left to right. The simplifier now preserves
    71     the order of assumptions.
    72 
    73     Potential INCOMPATIBILITY:
    74 
    75     -- simp sometimes diverges where the old version did
    76        not, e.g. invoking simp on the goal
    77 
    78         [| P (f x); y = x; f x = f y |] ==> Q
    79 
    80        now gives rise to the infinite reduction sequence
    81 
    82         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
    83 
    84        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
    85        kind of problem.
    86 
    87     -- Tactics combining classical reasoner and simplification (such as auto)
    88        are also affected by this change, because many of them rely on
    89        simp. They may sometimes diverge as well or yield a different numbers
    90        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
    91        in case of problems. Sometimes subsequent calls to the classical
    92        reasoner will fail because a preceeding call to the simplifier too
    93        eagerly simplified the goal, e.g. deleted redundant premises.
    94 
    95   - The simplifier trace now shows the names of the applied rewrite rules
    96 
    97   - You can limit the number of recursive invocations of the simplifier
    98     during conditional rewriting (where the simplifie tries to solve the
    99     conditions before applying the rewrite rule):
   100     ML "simp_depth_limit := n"
   101     where n is an integer. Thus you can force termination where previously
   102     the simplifier would diverge.
   103 
   104   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   105 
   106   - No longer aborts on failed congruence proof.  Instead, the
   107     congruence is ignored.
   108 
   109 * Pure: New generic framework for extracting programs from constructive
   110   proofs. See HOL/Extraction.thy for an example instantiation, as well
   111   as HOL/Extraction for some case studies.
   112 
   113 * Pure: The main goal of the proof state is no longer shown by default, only
   114 the subgoals. This behaviour is controlled by a new flag.
   115    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   116 (ML: Proof.show_main_goal).
   117 
   118 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   119 rules whose conclusion matches subgoal 1:
   120       PG menu: Isabelle/Isar -> Show me -> matching rules
   121 The rules are ordered by how closely they match the subgoal.
   122 In particular, rules that solve a subgoal outright are displayed first
   123 (or rather last, the way they are printed).
   124 (ML: ProofGeneral.print_intros())
   125 
   126 * Pure: New flag trace_unify_fail causes unification to print
   127 diagnostic information (PG: in trace buffer) when it fails. This is
   128 useful for figuring out why single step proofs like rule, erule or
   129 assumption failed.
   130 
   131 * Pure: Locale specifications now produce predicate definitions
   132 according to the body of text (covering assumptions modulo local
   133 definitions); predicate "loc_axioms" covers newly introduced text,
   134 while "loc" is cumulative wrt. all included locale expressions; the
   135 latter view is presented only on export into the global theory
   136 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   137 on the old view without predicates;
   138 
   139 * Pure: predefined locales "var" and "struct" are useful for sharing
   140 parameters (as in CASL, for example); just specify something like
   141 ``var x + var y + struct M'' as import;
   142 
   143 * Pure: improved thms_containing: proper indexing of facts instead of
   144 raw theorems; check validity of results wrt. current name space;
   145 include local facts of proof configuration (also covers active
   146 locales), cover fixed variables in index; may use "_" in term
   147 specification; an optional limit for the number of printed facts may
   148 be given (the default is 40);
   149 
   150 * Pure: disallow duplicate fact bindings within new-style theory files
   151 (batch-mode only);
   152 
   153 * Provers: improved induct method: assumptions introduced by case
   154 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   155 the goal statement); "foo" still refers to all facts collectively;
   156 
   157 * Provers: the function blast.overloaded has been removed: all constants
   158 are regarded as potentially overloaded, which improves robustness in exchange
   159 for slight decrease in efficiency;
   160 
   161 * Provers/linorder: New generic prover for transitivity reasoning over
   162 linear orders.  Note: this prover is not efficient!
   163 
   164 * Isar: preview of problems to finish 'show' now produce an error
   165 rather than just a warning (in interactive mode);
   166 
   167 
   168 *** HOL ***
   169 
   170 * arith(_tac)
   171 
   172  - Produces a counter example if it cannot prove a goal.
   173    Note that the counter example may be spurious if the goal is not a formula
   174    of quantifier-free linear arithmetic.
   175    In ProofGeneral the counter example appears in the trace buffer.
   176 
   177  - Knows about div k and mod k where k is a numeral of type nat or int.
   178 
   179  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   180    linear arithmetic fails. This takes account of quantifiers and divisibility.
   181    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   182 
   183 * simp's arithmetic capabilities have been enhanced a bit: it now
   184 takes ~= in premises into account (by performing a case split);
   185 
   186 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   187 are distributed over a sum of terms;
   188 
   189 * New tactic "trans_tac" and method "trans" instantiate
   190 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   191 "<=", "<" and "="). 
   192 
   193 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   194 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   195 
   196 * 'typedef' command has new option "open" to suppress the set
   197 definition;
   198 
   199 * functions Min and Max on finite sets have been introduced (theory
   200 Finite_Set);
   201 
   202 * attribute [symmetric] now works for relations as well; it turns
   203 (x,y) : R^-1 into (y,x) : R, and vice versa;
   204 
   205 * induct over a !!-quantified statement (say !!x1..xn):
   206   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   207 
   208 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   209 %x. None. Warning: empty_def now refers to the previously hidden definition
   210 of the empty set.
   211 
   212 * Algebra: formalization of classical algebra.  Intended as base for
   213 any algebraic development in Isabelle.  Currently covers group theory
   214 (up to Sylow's theorem) and ring theory (Universal Property of
   215 Univariate Polynomials).  Contributions welcome;
   216 
   217 * GroupTheory: deleted, since its material has been moved to Algebra;
   218 
   219 * Complex: new directory of the complex numbers with numeric constants, 
   220 nonstandard complex numbers, and some complex analysis, standard and 
   221 nonstandard (Jacques Fleuriot);
   222 
   223 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   224 
   225 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   226 Fleuriot);
   227 
   228 * Real/HahnBanach: updated and adapted to locales;
   229 
   230 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   231 Gray and Kramer);
   232 
   233 * UNITY: added the Meier-Sanders theory of progress sets;
   234 
   235 * MicroJava: bytecode verifier and lightweight bytecode verifier
   236 as abstract algorithms, instantiated to the JVM;
   237 
   238 * Bali: Java source language formalization. Type system, operational
   239 semantics, axiomatic semantics. Supported language features:
   240 classes, interfaces, objects,virtual methods, static methods,
   241 static/instance fields, arrays, access modifiers, definite
   242 assignment, exceptions.
   243 
   244 
   245 *** ZF ***
   246 
   247 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   248 universe, etc.);
   249 
   250 * Main ZF: virtually all theories converted to new-style format;
   251 
   252 
   253 *** ML ***
   254 
   255 * Pure: Tactic.prove provides sane interface for internal proofs;
   256 omits the infamous "standard" operation, so this is more appropriate
   257 than prove_goalw_cterm in many situations (e.g. in simprocs);
   258 
   259 * Pure: improved error reporting of simprocs;
   260 
   261 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   262 up simprocs;
   263 
   264 
   265 *** Document preparation ***
   266 
   267 * uses \par instead of \\ for line breaks in theory text. This may
   268 shift some page breaks in large documents. To get the old behaviour
   269 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   270 
   271 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   272 other packages
   273 
   274 * \<euro> now needs package babel/greek instead of marvosym (which
   275 broke \Rightarrow)
   276 
   277 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   278 textcomp package)
   279 
   280 
   281 New in Isabelle2002 (March 2002)
   282 --------------------------------
   283 
   284 *** Document preparation ***
   285 
   286 * greatly simplified document preparation setup, including more
   287 graceful interpretation of isatool usedir -i/-d/-D options, and more
   288 instructive isatool mkdir; users should basically be able to get
   289 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   290 users may run a separate document processing stage manually like this:
   291 "isatool usedir -D output HOL Test && isatool document Test/output";
   292 
   293 * theory dependency graph may now be incorporated into documents;
   294 isatool usedir -g true will produce session_graph.eps/.pdf for use
   295 with \includegraphics of LaTeX;
   296 
   297 * proper spacing of consecutive markup elements, especially text
   298 blocks after section headings;
   299 
   300 * support bold style (for single symbols only), input syntax is like
   301 this: "\<^bold>\<alpha>" or "\<^bold>A";
   302 
   303 * \<bullet> is now output as bold \cdot by default, which looks much
   304 better in printed text;
   305 
   306 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   307 note that these symbols are currently unavailable in Proof General /
   308 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   309 
   310 * isatool latex no longer depends on changed TEXINPUTS, instead
   311 isatool document copies the Isabelle style files to the target
   312 location;
   313 
   314 
   315 *** Isar ***
   316 
   317 * Pure/Provers: improved proof by cases and induction;
   318   - 'case' command admits impromptu naming of parameters (such as
   319     "case (Suc n)");
   320   - 'induct' method divinates rule instantiation from the inductive
   321     claim; no longer requires excessive ?P bindings for proper
   322     instantiation of cases;
   323   - 'induct' method properly enumerates all possibilities of set/type
   324     rules; as a consequence facts may be also passed through *type*
   325     rules without further ado;
   326   - 'induct' method now derives symbolic cases from the *rulified*
   327     rule (before it used to rulify cases stemming from the internal
   328     atomized version); this means that the context of a non-atomic
   329     statement becomes is included in the hypothesis, avoiding the
   330     slightly cumbersome show "PROP ?case" form;
   331   - 'induct' may now use elim-style induction rules without chaining
   332     facts, using ``missing'' premises from the goal state; this allows
   333     rules stemming from inductive sets to be applied in unstructured
   334     scripts, while still benefitting from proper handling of non-atomic
   335     statements; NB: major inductive premises need to be put first, all
   336     the rest of the goal is passed through the induction;
   337   - 'induct' proper support for mutual induction involving non-atomic
   338     rule statements (uses the new concept of simultaneous goals, see
   339     below);
   340   - append all possible rule selections, but only use the first
   341     success (no backtracking);
   342   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   343   - undeclared rule case names default to numbers 1, 2, 3, ...;
   344   - added 'print_induct_rules' (covered by help item in recent Proof
   345     General versions);
   346   - moved induct/cases attributes to Pure, methods to Provers;
   347   - generic method setup instantiated for FOL and HOL;
   348 
   349 * Pure: support multiple simultaneous goal statements, for example
   350 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   351 meta-level mechanism, this acts as if several individual goals had
   352 been stated separately; in particular common proof methods need to be
   353 repeated in order to cover all claims; note that a single elimination
   354 step is *not* sufficient to establish the two conjunctions, so this
   355 fails:
   356 
   357   assume "A & B" then have A and B ..   (*".." fails*)
   358 
   359 better use "obtain" in situations as above; alternative refer to
   360 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   361 
   362 * Pure: proper integration with ``locales''; unlike the original
   363 version by Florian Kammüller, Isar locales package high-level proof
   364 contexts rather than raw logical ones (e.g. we admit to include
   365 attributes everywhere); operations on locales include merge and
   366 rename; support for implicit arguments (``structures''); simultaneous
   367 type-inference over imports and text; see also HOL/ex/Locales.thy for
   368 some examples;
   369 
   370 * Pure: the following commands have been ``localized'', supporting a
   371 target locale specification "(in name)": 'lemma', 'theorem',
   372 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   373 stored both within the locale and at the theory level (exported and
   374 qualified by the locale name);
   375 
   376 * Pure: theory goals may now be specified in ``long'' form, with
   377 ad-hoc contexts consisting of arbitrary locale elements. for example
   378 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   379 definitions may be given, too); the result is a meta-level rule with
   380 the context elements being discharged in the obvious way;
   381 
   382 * Pure: new proof command 'using' allows to augment currently used
   383 facts after a goal statement ('using' is syntactically analogous to
   384 'apply', but acts on the goal's facts only); this allows chained facts
   385 to be separated into parts given before and after a claim, as in
   386 ``from a and b have C using d and e <proof>'';
   387 
   388 * Pure: renamed "antecedent" case to "rule_context";
   389 
   390 * Pure: new 'judgment' command records explicit information about the
   391 object-logic embedding (used by several tools internally); no longer
   392 use hard-wired "Trueprop";
   393 
   394 * Pure: added 'corollary' command;
   395 
   396 * Pure: fixed 'token_translation' command;
   397 
   398 * Pure: removed obsolete 'exported' attribute;
   399 
   400 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   401 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   402 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   403 
   404 * Pure: method 'atomize' presents local goal premises as object-level
   405 statements (atomic meta-level propositions); setup controlled via
   406 rewrite rules declarations of 'atomize' attribute; example
   407 application: 'induct' method with proper rule statements in improper
   408 proof *scripts*;
   409 
   410 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   411 now consider the syntactic context of assumptions, giving a better
   412 chance to get type-inference of the arguments right (this is
   413 especially important for locales);
   414 
   415 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   416 mode;
   417 
   418 * Pure/obtain: the formal conclusion "thesis", being marked as
   419 ``internal'', may no longer be reference directly in the text;
   420 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   421 situations;
   422 
   423 * Pure: generic 'sym' attribute which declares a rule both as pure
   424 'elim?' and for the 'symmetric' operation;
   425 
   426 * Pure: marginal comments ``--'' may now occur just anywhere in the
   427 text; the fixed correlation with particular command syntax has been
   428 discontinued;
   429 
   430 * Pure: new method 'rules' is particularly well-suited for proof
   431 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   432 but often produces more compact proof terms with less detours;
   433 
   434 * Pure/Provers/classical: simplified integration with pure rule
   435 attributes and methods; the classical "intro?/elim?/dest?"
   436 declarations coincide with the pure ones; the "rule" method no longer
   437 includes classically swapped intros; "intro" and "elim" methods no
   438 longer pick rules from the context; also got rid of ML declarations
   439 AddXIs/AddXEs/AddXDs; all of this has some potential for
   440 INCOMPATIBILITY;
   441 
   442 * Provers/classical: attribute 'swapped' produces classical inversions
   443 of introduction rules;
   444 
   445 * Provers/simplifier: 'simplified' attribute may refer to explicit
   446 rules instead of full simplifier context; 'iff' attribute handles
   447 conditional rules;
   448 
   449 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   450 
   451 * HOL: 'recdef' now fails on unfinished automated proofs, use
   452 "(permissive)" option to recover old behavior;
   453 
   454 * HOL: 'inductive' no longer features separate (collective) attributes
   455 for 'intros' (was found too confusing);
   456 
   457 * HOL: properly declared induction rules less_induct and
   458 wf_induct_rule;
   459 
   460 
   461 *** HOL ***
   462 
   463 * HOL: moved over to sane numeral syntax; the new policy is as
   464 follows:
   465 
   466   - 0 and 1 are polymorphic constants, which are defined on any
   467   numeric type (nat, int, real etc.);
   468 
   469   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   470   binary representation internally;
   471 
   472   - type nat has special constructor Suc, and generally prefers Suc 0
   473   over 1::nat and Suc (Suc 0) over 2::nat;
   474 
   475 This change may cause significant problems of INCOMPATIBILITY; here
   476 are some hints on converting existing sources:
   477 
   478   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   479   entities, so expressions involving "-" (unary or binary minus) need
   480   to be spaced properly;
   481 
   482   - existing occurrences of "1" may need to be constraint "1::nat" or
   483   even replaced by Suc 0; similar for old "2";
   484 
   485   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   486 
   487   - remove all special provisions on numerals in proofs;
   488 
   489 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   490 representation (depends on bin_arith_simps in the default context);
   491 
   492 * HOL: symbolic syntax for x^2 (numeral 2);
   493 
   494 * HOL: the class of all HOL types is now called "type" rather than
   495 "term"; INCOMPATIBILITY, need to adapt references to this type class
   496 in axclass/classes, instance/arities, and (usually rare) occurrences
   497 in typings (of consts etc.); internally the class is called
   498 "HOL.type", ML programs should refer to HOLogic.typeS;
   499 
   500 * HOL/record package improvements:
   501   - new derived operations "fields" to build a partial record section,
   502     "extend" to promote a fixed record to a record scheme, and
   503     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   504     declared as simp by default;
   505   - shared operations ("more", "fields", etc.) now need to be always
   506     qualified) --- potential INCOMPATIBILITY;
   507   - removed "make_scheme" operations (use "make" with "extend") --
   508     INCOMPATIBILITY;
   509   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   510   - provides cases/induct rules for use with corresponding Isar
   511     methods (for concrete records, record schemes, concrete more
   512     parts, and schematic more parts -- in that order);
   513   - internal definitions directly based on a light-weight abstract
   514     theory of product types over typedef rather than datatype;
   515 
   516 * HOL: generic code generator for generating executable ML code from
   517 specifications; specific support for HOL constructs such as inductive
   518 datatypes and sets, as well as recursive functions; can be invoked
   519 via 'generate_code' theory section;
   520 
   521 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   522 
   523 * HOL: consolidated and renamed several theories.  In particular:
   524 	Ord.thy has been absorbed into HOL.thy
   525 	String.thy has been absorbed into List.thy
   526  
   527 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   528 (beware of argument permutation!);
   529 
   530 * HOL: linorder_less_split superseded by linorder_cases;
   531 
   532 * HOL/List: "nodups" renamed to "distinct";
   533 
   534 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   535 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   536   - Ex_def has changed, now need to use some_eq_ex
   537 
   538 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   539 in this (rare) case use:
   540 
   541   delSWrapper "split_all_tac"
   542   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   543 
   544 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   545 MAY FAIL;
   546 
   547 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   548 Isabelle's type classes, ^ on functions and relations has too general
   549 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   550 necessary to attach explicit type constraints;
   551 
   552 * HOL/Relation: the prefix name of the infix "O" has been changed from
   553 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   554 renamed accordingly (eg "compI" -> "rel_compI").
   555 
   556 * HOL: syntax translations now work properly with numerals and records
   557 expressions;
   558 
   559 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   560 of "lam" -- INCOMPATIBILITY;
   561 
   562 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   563 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   564 renamed "Product_Type.unit";
   565 
   566 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   567 
   568 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   569 the "cases" method);
   570 
   571 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   572 Florian Kammüller);
   573 
   574 * HOL/IMP: updated and converted to new-style theory format; several
   575 parts turned into readable document, with proper Isar proof texts and
   576 some explanations (by Gerwin Klein);
   577 
   578 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   579 
   580 * HOL-Hyperreal is now a logic image;
   581 
   582 
   583 *** HOLCF ***
   584 
   585 * Isar: consts/constdefs supports mixfix syntax for continuous
   586 operations;
   587 
   588 * Isar: domain package adapted to new-style theory format, e.g. see
   589 HOLCF/ex/Dnat.thy;
   590 
   591 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   592 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   593 lift.induct_tac, always use UU instead of Undef;
   594 
   595 * HOLCF/IMP: updated and converted to new-style theory;
   596 
   597 
   598 *** ZF ***
   599 
   600 * Isar: proper integration of logic-specific tools and packages,
   601 including theory commands '(co)inductive', '(co)datatype',
   602 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   603 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   604 
   605 * theory Main no longer includes AC; for the Axiom of Choice, base
   606 your theory on Main_ZFC;
   607 
   608 * the integer library now covers quotients and remainders, with many
   609 laws relating division to addition, multiplication, etc.;
   610 
   611 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   612 typeless version of the formalism;
   613 
   614 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   615 format;
   616 
   617 * ZF/Induct: new directory for examples of inductive definitions,
   618 including theory Multiset for multiset orderings; converted to
   619 new-style theory format;
   620 
   621 * ZF: many new theorems about lists, ordinals, etc.;
   622 
   623 
   624 *** General ***
   625 
   626 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   627 variable proof controls level of detail: 0 = no proofs (only oracle
   628 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   629 also ref manual for further ML interfaces;
   630 
   631 * Pure/axclass: removed obsolete ML interface
   632 goal_subclass/goal_arity;
   633 
   634 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   635 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   636 separate tokens, so expressions involving minus need to be spaced
   637 properly;
   638 
   639 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   640 rather than "infixl" or "infixr";
   641 
   642 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   643 sort constraint specifications in type inference; e.g. "x::_::foo"
   644 ensures that the type of "x" is of sort "foo" (but not necessarily a
   645 type variable);
   646 
   647 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   648 control output of nested => (types); the default behavior is
   649 "type_brackets";
   650 
   651 * Pure/syntax: builtin parse translation for "_constify" turns valued
   652 tokens into AST constants;
   653 
   654 * Pure/syntax: prefer later declarations of translations and print
   655 translation functions; potential INCOMPATIBILITY: need to reverse
   656 multiple declarations for same syntax element constant;
   657 
   658 * Pure/show_hyps reset by default (in accordance to existing Isar
   659 practice);
   660 
   661 * Provers/classical: renamed addaltern to addafter, addSaltern to
   662 addSafter;
   663 
   664 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   665 as well;
   666 
   667 * system: tested support for MacOS X; should be able to get Isabelle +
   668 Proof General to work in a plain Terminal after installing Poly/ML
   669 (e.g. from the Isabelle distribution area) and GNU bash alone
   670 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   671 support requires further installations, e.g. from
   672 http://fink.sourceforge.net/);
   673 
   674 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   675 
   676 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   677 of 40 MB), cf. ML_OPTIONS;
   678 
   679 * system: Proof General keywords specification is now part of the
   680 Isabelle distribution (see etc/isar-keywords.el);
   681 
   682 * system: support for persistent Proof General sessions (refrain from
   683 outdating all loaded theories on startup); user may create writable
   684 logic images like this: ``isabelle -q HOL Test'';
   685 
   686 * system: smart selection of Isabelle process versus Isabelle
   687 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   688 run both "isabelle" and "Isabelle" even if file names are badly
   689 damaged (executable inspects the case of the first letter of its own
   690 name); added separate "isabelle-process" and "isabelle-interface";
   691 
   692 * system: refrain from any attempt at filtering input streams; no
   693 longer support ``8bit'' encoding of old isabelle font, instead proper
   694 iso-latin characters may now be used; the related isatools
   695 "symbolinput" and "nonascii" have disappeared as well;
   696 
   697 * system: removed old "xterm" interface (the print modes "xterm" and
   698 "xterm_color" are still available for direct use in a suitable
   699 terminal);
   700 
   701 
   702 
   703 New in Isabelle99-2 (February 2001)
   704 -----------------------------------
   705 
   706 *** Overview of INCOMPATIBILITIES ***
   707 
   708 * HOL: please note that theories in the Library and elsewhere often use the
   709 new-style (Isar) format; to refer to their theorems in an ML script you must
   710 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   711 
   712 * HOL: inductive package no longer splits induction rule aggressively,
   713 but only as far as specified by the introductions given; the old
   714 format may be recovered via ML function complete_split_rule or attribute
   715 'split_rule (complete)';
   716 
   717 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   718 gfp_Tarski to gfp_unfold;
   719 
   720 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   721 
   722 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   723 relation); infix "^^" has been renamed "``"; infix "``" has been
   724 renamed "`"; "univalent" has been renamed "single_valued";
   725 
   726 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   727 operation;
   728 
   729 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   730 
   731 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   732 
   733 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   734 consequence, it is no longer monotonic wrt. the local goal context
   735 (which is now passed through the inductive cases);
   736 
   737 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   738 \<gg> to \<ggreater>;
   739 
   740 
   741 *** Document preparation ***
   742 
   743 * \isabellestyle{NAME} selects version of Isabelle output (currently
   744 available: are "it" for near math-mode best-style output, "sl" for
   745 slanted text style, and "tt" for plain type-writer; if no
   746 \isabellestyle command is given, output is according to slanted
   747 type-writer);
   748 
   749 * support sub/super scripts (for single symbols only), input syntax is
   750 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   751 
   752 * some more standard symbols; see Appendix A of the system manual for
   753 the complete list of symbols defined in isabellesym.sty;
   754 
   755 * improved isabelle style files; more abstract symbol implementation
   756 (should now use \isamath{...} and \isatext{...} in custom symbol
   757 definitions);
   758 
   759 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   760 state; Note that presentation of goal states does not conform to
   761 actual human-readable proof documents.  Please do not include goal
   762 states into document output unless you really know what you are doing!
   763 
   764 * proper indentation of antiquoted output with proportional LaTeX
   765 fonts;
   766 
   767 * no_document ML operator temporarily disables LaTeX document
   768 generation;
   769 
   770 * isatool unsymbolize tunes sources for plain ASCII communication;
   771 
   772 
   773 *** Isar ***
   774 
   775 * Pure: Isar now suffers initial goal statements to contain unbound
   776 schematic variables (this does not conform to actual readable proof
   777 documents, due to unpredictable outcome and non-compositional proof
   778 checking); users who know what they are doing may use schematic goals
   779 for Prolog-style synthesis of proven results;
   780 
   781 * Pure: assumption method (an implicit finishing) now handles actual
   782 rules as well;
   783 
   784 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   785 initial goal, declare "that" only as Pure intro (only for single
   786 steps); the "that" rule assumption may now be involved in implicit
   787 finishing, thus ".." becomes a feasible for trivial obtains;
   788 
   789 * Pure: default proof step now includes 'intro_classes'; thus trivial
   790 instance proofs may be performed by "..";
   791 
   792 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   793 statements as well;
   794 
   795 * Pure: more robust selection of calculational rules;
   796 
   797 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   798 rule (as well as the assumption rule);
   799 
   800 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   801 lemmas, using the graph browser tool;
   802 
   803 * Pure: predict failure of "show" in interactive mode;
   804 
   805 * Pure: 'thms_containing' now takes actual terms as arguments;
   806 
   807 * HOL: improved method 'induct' --- now handles non-atomic goals
   808 (potential INCOMPATIBILITY); tuned error handling;
   809 
   810 * HOL: cases and induct rules now provide explicit hints about the
   811 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   812 any remaining facts are inserted into the goal verbatim;
   813 
   814 * HOL: local contexts (aka cases) may now contain term bindings as
   815 well; the 'cases' and 'induct' methods new provide a ?case binding for
   816 the result to be shown in each case;
   817 
   818 * HOL: added 'recdef_tc' command;
   819 
   820 * isatool convert assists in eliminating legacy ML scripts;
   821 
   822 
   823 *** HOL ***
   824 
   825 * HOL/Library: a collection of generic theories to be used together
   826 with main HOL; the theory loader path already includes this directory
   827 by default; the following existing theories have been moved here:
   828 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   829 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   830 
   831 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   832 modelling and verification task performed in Isabelle/HOL +
   833 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   834 
   835 * HOL/Algebra: special summation operator SUM no longer exists, it has
   836 been replaced by setsum; infix 'assoc' now has priority 50 (like
   837 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   838 'domain', this makes the theory consistent with mathematical
   839 literature;
   840 
   841 * HOL basics: added overloaded operations "inverse" and "divide"
   842 (infix "/"), syntax for generic "abs" operation, generic summation
   843 operator \<Sum>;
   844 
   845 * HOL/typedef: simplified package, provide more useful rules (see also
   846 HOL/subset.thy);
   847 
   848 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   849 now expressed as a proper nested rule (old-style tactic scripts may
   850 require atomize_strip_tac to cope with non-atomic premises);
   851 
   852 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   853 to "split_conv" (old name still available for compatibility);
   854 
   855 * HOL: improved concrete syntax for strings (e.g. allows translation
   856 rules with string literals);
   857 
   858 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   859  and Fleuriot's mechanization of analysis, including the transcendental
   860  functions for the reals;
   861 
   862 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   863 
   864 
   865 *** CTT ***
   866 
   867 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   868 "lam" is displayed as TWO lambda-symbols
   869 
   870 * CTT: theory Main now available, containing everything (that is, Bool
   871 and Arith);
   872 
   873 
   874 *** General ***
   875 
   876 * Pure: the Simplifier has been implemented properly as a derived rule
   877 outside of the actual kernel (at last!); the overall performance
   878 penalty in practical applications is about 50%, while reliability of
   879 the Isabelle inference kernel has been greatly improved;
   880 
   881 * print modes "brackets" and "no_brackets" control output of nested =>
   882 (types) and ==> (props); the default behaviour is "brackets";
   883 
   884 * Provers: fast_tac (and friends) now handle actual object-logic rules
   885 as assumptions as well;
   886 
   887 * system: support Poly/ML 4.0;
   888 
   889 * system: isatool install handles KDE version 1 or 2;
   890 
   891 
   892 
   893 New in Isabelle99-1 (October 2000)
   894 ----------------------------------
   895 
   896 *** Overview of INCOMPATIBILITIES ***
   897 
   898 * HOL: simplification of natural numbers is much changed; to partly
   899 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   900 issue the following ML commands:
   901 
   902   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   903   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   904 
   905 * HOL: simplification no longer dives into case-expressions; this is
   906 controlled by "t.weak_case_cong" for each datatype t;
   907 
   908 * HOL: nat_less_induct renamed to less_induct;
   909 
   910 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   911 fixsome to patch .thy and .ML sources automatically;
   912 
   913   select_equality  -> some_equality
   914   select_eq_Ex     -> some_eq_ex
   915   selectI2EX       -> someI2_ex
   916   selectI2         -> someI2
   917   selectI          -> someI
   918   select1_equality -> some1_equality
   919   Eps_sym_eq       -> some_sym_eq_trivial
   920   Eps_eq           -> some_eq_trivial
   921 
   922 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   923 
   924 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   925 instead);
   926 
   927 * HOL: the recursion equations generated by 'recdef' are now called
   928 f.simps instead of f.rules;
   929 
   930 * HOL: qed_spec_mp now also handles bounded ALL as well;
   931 
   932 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   933 sometimes be needed;
   934 
   935 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   936 
   937 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   938 
   939 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   940 product is now "<*>" instead of "Times"; the lexicographic product is
   941 now "<*lex*>" instead of "**";
   942 
   943 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   944 of main HOL, but was unused); better use HOL's datatype package;
   945 
   946 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   947 the old syntax may be recovered as follows:
   948 
   949   syntax (symbols)
   950     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   951       (infixl "\\<oplus>" 100)
   952 
   953 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   954 
   955 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   956 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   957 internally;
   958 
   959 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   960 changed from A/r to A//r;
   961 
   962 * ZF: new treatment of arithmetic (nat & int) may break some old
   963 proofs;
   964 
   965 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   966 rulify -> rule_format, elimify -> elim_format, ...);
   967 
   968 * Isar/Provers: intro/elim/dest attributes changed; renamed
   969 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   970 should have to change intro!! to intro? only); replaced "delrule" by
   971 "rule del";
   972 
   973 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   974 
   975 * Provers: strengthened force_tac by using new first_best_tac;
   976 
   977 * LaTeX document preparation: several changes of isabelle.sty (see
   978 lib/texinputs);
   979 
   980 
   981 *** Document preparation ***
   982 
   983 * formal comments (text blocks etc.) in new-style theories may now
   984 contain antiquotations of thm/prop/term/typ/text to be presented
   985 according to latex print mode; concrete syntax is like this:
   986 @{term[show_types] "f(x) = a + x"};
   987 
   988 * isatool mkdir provides easy setup of Isabelle session directories,
   989 including proper document sources;
   990 
   991 * generated LaTeX sources are now deleted after successful run
   992 (isatool document -c); may retain a copy somewhere else via -D option
   993 of isatool usedir;
   994 
   995 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
   996 style files, achieving self-contained LaTeX sources and simplifying
   997 LaTeX debugging;
   998 
   999 * old-style theories now produce (crude) LaTeX output as well;
  1000 
  1001 * browser info session directories are now self-contained (may be put
  1002 on WWW server seperately); improved graphs of nested sessions; removed
  1003 graph for 'all sessions';
  1004 
  1005 * several improvements in isabelle style files; \isabellestyle{it}
  1006 produces fake math mode output; \isamarkupheader is now \section by
  1007 default; see lib/texinputs/isabelle.sty etc.;
  1008 
  1009 
  1010 *** Isar ***
  1011 
  1012 * Isar/Pure: local results and corresponding term bindings are now
  1013 subject to Hindley-Milner polymorphism (similar to ML); this
  1014 accommodates incremental type-inference very nicely;
  1015 
  1016 * Isar/Pure: new derived language element 'obtain' supports
  1017 generalized existence reasoning;
  1018 
  1019 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1020 support accumulation of results, without applying any rules yet;
  1021 useful to collect intermediate results without explicit name
  1022 references, and for use with transitivity rules with more than 2
  1023 premises;
  1024 
  1025 * Isar/Pure: scalable support for case-analysis type proofs: new
  1026 'case' language element refers to local contexts symbolically, as
  1027 produced by certain proof methods; internally, case names are attached
  1028 to theorems as "tags";
  1029 
  1030 * Isar/Pure: theory command 'hide' removes declarations from
  1031 class/type/const name spaces;
  1032 
  1033 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1034 indicate potential overloading;
  1035 
  1036 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1037 
  1038 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1039 "{a,b,c}" instead of {a,b,c};
  1040 
  1041 * Isar/Pure now provides its own version of intro/elim/dest
  1042 attributes; useful for building new logics, but beware of confusion
  1043 with the version in Provers/classical;
  1044 
  1045 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1046 case name 'antecedent';
  1047 
  1048 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1049 to the current context is now done automatically);
  1050 
  1051 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1052 for definining proof methods in ML;
  1053 
  1054 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1055 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1056 most cases, one should have to change intro!! to intro? only);
  1057 replaced "delrule" by "rule del";
  1058 
  1059 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1060 'symmetric' attribute (the latter supercedes [RS sym]);
  1061 
  1062 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1063 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1064 well (including splits);
  1065 
  1066 * Isar/Provers: Simplifier and Classical methods now support all kind
  1067 of modifiers used in the past, including 'cong', 'iff', etc.
  1068 
  1069 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1070 of Simplifier and Classical reasoner);
  1071 
  1072 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1073 now support named cases; major packages (inductive, datatype, primrec,
  1074 recdef) support case names and properly name parameters;
  1075 
  1076 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1077 monotonicity conditions are extracted to be proven at end of
  1078 calculations;
  1079 
  1080 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1081 method anyway;
  1082 
  1083 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1084 split_if split_if_asm; datatype package provides theorems foo.splits =
  1085 foo.split foo.split_asm for each datatype;
  1086 
  1087 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1088 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1089 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1090 use "(cases (simplified))" method in proper proof texts);
  1091 
  1092 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1093 
  1094 * Isar: names of theorems etc. may be natural numbers as well;
  1095 
  1096 * Isar: 'pr' command: optional arguments for goals_limit and
  1097 ProofContext.prems_limit; no longer prints theory contexts, but only
  1098 proof states;
  1099 
  1100 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1101 additional print modes to be specified; e.g. "pr(latex)" will print
  1102 proof state according to the Isabelle LaTeX style;
  1103 
  1104 * Isar: improved support for emulating tactic scripts, including proof
  1105 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1106 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1107 (for HOL datatypes);
  1108 
  1109 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1110 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1111 'proof method scripts' have to be in depth-first order;
  1112 
  1113 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1114 
  1115 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1116 should instead use individual commands for printing items
  1117 (print_commands, print_methods etc.);
  1118 
  1119 * Isar: added 'nothing' --- the empty list of theorems;
  1120 
  1121 
  1122 *** HOL ***
  1123 
  1124 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1125 corresponding virtual machine and a specification of its bytecode
  1126 verifier and a lightweight bytecode verifier, including proofs of
  1127 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1128 Cornelia Pusch (see also the homepage of project Bali at
  1129 http://isabelle.in.tum.de/Bali/);
  1130 
  1131 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1132 Clemens Ballarin;
  1133 
  1134 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1135 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1136 Rasmussen;
  1137 
  1138 * HOL/Lattice: fundamental concepts of lattice theory and order
  1139 structures, including duals, properties of bounds versus algebraic
  1140 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1141 Theorem for complete lattices etc.; may also serve as a demonstration
  1142 for abstract algebraic reasoning using axiomatic type classes, and
  1143 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1144 
  1145 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1146 von Oheimb;
  1147 
  1148 * HOL/IMPP: extension of IMP with local variables and mutually
  1149 recursive procedures, by David von Oheimb;
  1150 
  1151 * HOL/Lambda: converted into new-style theory and document;
  1152 
  1153 * HOL/ex/Multiquote: example of multiple nested quotations and
  1154 anti-quotations -- basically a generalized version of de-Bruijn
  1155 representation; very useful in avoiding lifting of operations;
  1156 
  1157 * HOL/record: added general record equality rule to simpset; fixed
  1158 select-update simplification procedure to handle extended records as
  1159 well; admit "r" as field name;
  1160 
  1161 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1162 other numeric types and also as the identity of groups, rings, etc.;
  1163 
  1164 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1165 Types nat and int belong to this axclass;
  1166 
  1167 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1168    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1169    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1170   two terms #m*u and #n*u are replaced by #(m+n)*u
  1171     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1172   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1173     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1174 
  1175 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1176 powerful prover for predicate logic but knows nothing of clasets; see
  1177 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1178 
  1179 * HOL: new version of "case_tac" subsumes both boolean case split and
  1180 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1181 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1182 
  1183 * HOL: simplification no longer dives into case-expressions: only the
  1184 selector expression is simplified, but not the remaining arms; to
  1185 enable full simplification of case-expressions for datatype t, you may
  1186 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1187 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1188 
  1189 * HOL/recdef: the recursion equations generated by 'recdef' for
  1190 function 'f' are now called f.simps instead of f.rules; if all
  1191 termination conditions are proved automatically, these simplification
  1192 rules are added to the simpset, as in primrec; rules may be named
  1193 individually as well, resulting in a separate list of theorems for
  1194 each equation;
  1195 
  1196 * HOL/While is a new theory that provides a while-combinator. It
  1197 permits the definition of tail-recursive functions without the
  1198 provision of a termination measure. The latter is necessary once the
  1199 invariant proof rule for while is applied.
  1200 
  1201 * HOL: new (overloaded) notation for the set of elements below/above
  1202 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1203 
  1204 * HOL: theorems impI, allI, ballI bound as "strip";
  1205 
  1206 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1207 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1208 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1209 
  1210 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1211 
  1212 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1213 main HOL, but was unused);
  1214 
  1215 * HOL: fewer consts declared as global (e.g. have to refer to
  1216 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1217 
  1218 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1219 in case of overlap with user translations (e.g. judgements over
  1220 tuples); (note that the underlying logical represenation is still
  1221 bogus);
  1222 
  1223 
  1224 *** ZF ***
  1225 
  1226 * ZF: simplification automatically cancels common terms in arithmetic
  1227 expressions over nat and int;
  1228 
  1229 * ZF: new treatment of nat to minimize type-checking: all operators
  1230 coerce their operands to a natural number using the function natify,
  1231 making the algebraic laws unconditional;
  1232 
  1233 * ZF: as above, for int: operators coerce their operands to an integer
  1234 using the function intify;
  1235 
  1236 * ZF: the integer library now contains many of the usual laws for the
  1237 orderings, including $<=, and monotonicity laws for $+ and $*;
  1238 
  1239 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1240 simplification;
  1241 
  1242 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1243 to the simplifier and classical reasoner simultaneously;
  1244 
  1245 
  1246 *** General ***
  1247 
  1248 * Provers: blast_tac now handles actual object-logic rules as
  1249 assumptions; note that auto_tac uses blast_tac internally as well;
  1250 
  1251 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1252 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1253 
  1254 * Provers: delrules now handles destruct rules as well (no longer need
  1255 explicit make_elim);
  1256 
  1257 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1258   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1259 use instead the strong form,
  1260   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1261 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1262 from destruct-rules;
  1263 
  1264 * Provers: Simplifier.easy_setup provides a fast path to basic
  1265 Simplifier setup for new object-logics;
  1266 
  1267 * Pure: AST translation rules no longer require constant head on LHS;
  1268 
  1269 * Pure: improved name spaces: ambiguous output is qualified; support
  1270 for hiding of names;
  1271 
  1272 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1273 XSYMBOL_HOME; no longer need to do manual configuration in most
  1274 situations;
  1275 
  1276 * system: compression of ML heaps images may now be controlled via -c
  1277 option of isabelle and isatool usedir (currently only observed by
  1278 Poly/ML);
  1279 
  1280 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1281 useful for remote X11);
  1282 
  1283 * system: provide TAGS file for Isabelle sources;
  1284 
  1285 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1286 order;
  1287 
  1288 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1289 timing flag supersedes proof_timing and Toplevel.trace;
  1290 
  1291 * ML: new combinators |>> and |>>> for incremental transformations
  1292 with secondary results (e.g. certain theory extensions):
  1293 
  1294 * ML: PureThy.add_defs gets additional argument to indicate potential
  1295 overloading (usually false);
  1296 
  1297 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1298 results;
  1299 
  1300 
  1301 
  1302 New in Isabelle99 (October 1999)
  1303 --------------------------------
  1304 
  1305 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1306 
  1307 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1308 are no longer simplified.  (This allows the simplifier to unfold recursive
  1309 functional programs.)  To restore the old behaviour, declare
  1310 
  1311     Delcongs [if_weak_cong];
  1312 
  1313 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1314 complement;
  1315 
  1316 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1317 
  1318 * HOL/datatype: mutual_induct_tac no longer exists --
  1319   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1320 
  1321 * HOL/typedef: fixed type inference for representing set; type
  1322 arguments now have to occur explicitly on the rhs as type constraints;
  1323 
  1324 * ZF: The con_defs part of an inductive definition may no longer refer
  1325 to constants declared in the same theory;
  1326 
  1327 * HOL, ZF: the function mk_cases, generated by the inductive
  1328 definition package, has lost an argument.  To simplify its result, it
  1329 uses the default simpset instead of a supplied list of theorems.
  1330 
  1331 * HOL/List: the constructors of type list are now Nil and Cons;
  1332 
  1333 * Simplifier: the type of the infix ML functions
  1334         setSSolver addSSolver setSolver addSolver
  1335 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1336 for packaging solvers. A solver is created via
  1337         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1338 where the string argument is only a comment.
  1339 
  1340 
  1341 *** Proof tools ***
  1342 
  1343 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1344 decision procedure for linear arithmetic. Currently it is used for
  1345 types `nat', `int', and `real' in HOL (see below); it can, should and
  1346 will be instantiated for other types and logics as well.
  1347 
  1348 * The simplifier now accepts rewrite rules with flexible heads, eg
  1349      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1350   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1351   matching.
  1352 
  1353 
  1354 *** General ***
  1355 
  1356 * New Isabelle/Isar subsystem provides an alternative to traditional
  1357 tactical theorem proving; together with the ProofGeneral/isar user
  1358 interface it offers an interactive environment for developing human
  1359 readable proof documents (Isar == Intelligible semi-automated
  1360 reasoning); for further information see isatool doc isar-ref,
  1361 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1362 
  1363 * improved and simplified presentation of theories: better HTML markup
  1364 (including colors), graph views in several sizes; isatool usedir now
  1365 provides a proper interface for user theories (via -P option); actual
  1366 document preparation based on (PDF)LaTeX is available as well (for
  1367 new-style theories only); see isatool doc system for more information;
  1368 
  1369 * native support for Proof General, both for classic Isabelle and
  1370 Isabelle/Isar;
  1371 
  1372 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1373 using the graph browser tool;
  1374 
  1375 * Isabelle manuals now also available as PDF;
  1376 
  1377 * theory loader rewritten from scratch (may not be fully
  1378 bug-compatible); old loadpath variable has been replaced by show_path,
  1379 add_path, del_path, reset_path functions; new operations such as
  1380 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1381 isatool doc ref);
  1382 
  1383 * improved isatool install: option -k creates KDE application icon,
  1384 option -p DIR installs standalone binaries;
  1385 
  1386 * added ML_PLATFORM setting (useful for cross-platform installations);
  1387 more robust handling of platform specific ML images for SML/NJ;
  1388 
  1389 * the settings environment is now statically scoped, i.e. it is never
  1390 created again in sub-processes invoked from isabelle, isatool, or
  1391 Isabelle;
  1392 
  1393 * path element specification '~~' refers to '$ISABELLE_HOME';
  1394 
  1395 * in locales, the "assumes" and "defines" parts may be omitted if
  1396 empty;
  1397 
  1398 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1399 long arrows);
  1400 
  1401 * new print_mode "HTML";
  1402 
  1403 * new flag show_tags controls display of tags of theorems (which are
  1404 basically just comments that may be attached by some tools);
  1405 
  1406 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1407 mode and goal output format:
  1408 
  1409 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1410 244c244
  1411 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1412 ---
  1413 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1414 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1415 181c181
  1416 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1417 ---
  1418 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1419 
  1420 * function bind_thms stores lists of theorems (cf. bind_thm);
  1421 
  1422 * new shorthand tactics ftac, eatac, datac, fatac;
  1423 
  1424 * qed (and friends) now accept "" as result name; in that case the
  1425 theorem is not stored, but proper checks and presentation of the
  1426 result still apply;
  1427 
  1428 * theorem database now also indexes constants "Trueprop", "all",
  1429 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1430 
  1431 
  1432 *** HOL ***
  1433 
  1434 ** HOL arithmetic **
  1435 
  1436 * There are now decision procedures for linear arithmetic over nat and
  1437 int:
  1438 
  1439 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1440 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1441 are treated as atomic; subformulae not involving type `nat' or `int'
  1442 are ignored; quantified subformulae are ignored unless they are
  1443 positive universal or negative existential. The tactic has to be
  1444 invoked by hand and can be a little bit slow. In particular, the
  1445 running time is exponential in the number of occurrences of `min' and
  1446 `max', and `-' on `nat'.
  1447 
  1448 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1449 (negated) (in)equalities among the premises and the conclusion into
  1450 account (i.e. no compound formulae) and does not know about `min' and
  1451 `max', and `-' on `nat'. It is fast and is used automatically by the
  1452 simplifier.
  1453 
  1454 NB: At the moment, these decision procedures do not cope with mixed
  1455 nat/int formulae where the two parts interact, such as `m < n ==>
  1456 int(m) < int(n)'.
  1457 
  1458 * HOL/Numeral provides a generic theory of numerals (encoded
  1459 efficiently as bit strings); setup for types nat/int/real is in place;
  1460 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1461 int, existing theories and proof scripts may require a few additional
  1462 type constraints;
  1463 
  1464 * integer division and remainder can now be performed on constant
  1465 arguments;
  1466 
  1467 * many properties of integer multiplication, division and remainder
  1468 are now available;
  1469 
  1470 * An interface to the Stanford Validity Checker (SVC) is available through the
  1471 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1472 are proved automatically.  SVC must be installed separately, and its results
  1473 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1474 invocation of the underlying oracle).  For SVC see
  1475   http://verify.stanford.edu/SVC
  1476 
  1477 * IsaMakefile: the HOL-Real target now builds an actual image;
  1478 
  1479 
  1480 ** HOL misc **
  1481 
  1482 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1483 (in Isabelle/Isar) -- by Gertrud Bauer;
  1484 
  1485 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1486 analysis for assembly languages with subtypes;
  1487 
  1488 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1489 -- avoids syntactic ambiguities and treats state, transition, and
  1490 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1491 changed syntax and (many) tactics;
  1492 
  1493 * HOL/inductive: Now also handles more general introduction rules such
  1494   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1495   theorems are now maintained within the theory (maintained via the
  1496   "mono" attribute);
  1497 
  1498 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1499   (using function types) such as
  1500 
  1501   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1502 
  1503 * HOL/record: record_simproc (part of the default simpset) takes care
  1504 of selectors applied to updated records; record_split_tac is no longer
  1505 part of the default claset; update_defs may now be removed from the
  1506 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1507 
  1508   claset_ref () := claset() addSWrapper record_split_wrapper;
  1509   Delsimprocs [record_simproc]
  1510 
  1511 * HOL/typedef: fixed type inference for representing set; type
  1512 arguments now have to occur explicitly on the rhs as type constraints;
  1513 
  1514 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1515 names rather than an ML expression;
  1516 
  1517 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1518 supplied later.  Program schemes can be defined, such as
  1519     "While B C s = (if B s then While B C (C s) else s)"
  1520 where the well-founded relation can be chosen after B and C have been given.
  1521 
  1522 * HOL/List: the constructors of type list are now Nil and Cons;
  1523 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1524 course, ML tools referring to List.list.op # etc. have to be adapted;
  1525 
  1526 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1527 disabled by default; run isabelle with option -m HOL to get back to
  1528 the original Gordon/HOL-style output;
  1529 
  1530 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1531 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1532 
  1533 * HOL basic syntax simplified (more orthogonal): all variants of
  1534 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1535 Eps operator is provided as well: "SOME x. P[x]";
  1536 
  1537 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1538 
  1539 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1540 thus available for user theories;
  1541 
  1542 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1543 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1544 time;
  1545 
  1546 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1547 several times and then mp;
  1548 
  1549 
  1550 *** LK ***
  1551 
  1552 * the notation <<...>> is now available as a notation for sequences of
  1553 formulas;
  1554 
  1555 * the simplifier is now installed
  1556 
  1557 * the axiom system has been generalized (thanks to Soren Heilmann)
  1558 
  1559 * the classical reasoner now has a default rule database
  1560 
  1561 
  1562 *** ZF ***
  1563 
  1564 * new primrec section allows primitive recursive functions to be given
  1565 directly (as in HOL) over datatypes and the natural numbers;
  1566 
  1567 * new tactics induct_tac and exhaust_tac for induction (or case
  1568 analysis) over datatypes and the natural numbers;
  1569 
  1570 * the datatype declaration of type T now defines the recursor T_rec;
  1571 
  1572 * simplification automatically does freeness reasoning for datatype
  1573 constructors;
  1574 
  1575 * automatic type-inference, with AddTCs command to insert new
  1576 type-checking rules;
  1577 
  1578 * datatype introduction rules are now added as Safe Introduction rules
  1579 to the claset;
  1580 
  1581 * the syntax "if P then x else y" is now available in addition to
  1582 if(P,x,y);
  1583 
  1584 
  1585 *** Internal programming interfaces ***
  1586 
  1587 * tuned simplifier trace output; new flag debug_simp;
  1588 
  1589 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1590 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1591 
  1592 * AxClass.axclass_tac lost the theory argument;
  1593 
  1594 * tuned current_goals_markers semantics: begin / end goal avoids
  1595 printing empty lines;
  1596 
  1597 * removed prs and prs_fn hook, which was broken because it did not
  1598 include \n in its semantics, forcing writeln to add one
  1599 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1600 string -> unit if you really want to output text without newline;
  1601 
  1602 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1603 plain output, interface builders may have to enable 'isabelle_font'
  1604 mode to get Isabelle font glyphs as before;
  1605 
  1606 * refined token_translation interface; INCOMPATIBILITY: output length
  1607 now of type real instead of int;
  1608 
  1609 * theory loader actions may be traced via new ThyInfo.add_hook
  1610 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1611 your own database of information attached to *whole* theories -- as
  1612 opposed to intra-theory data slots offered via TheoryDataFun;
  1613 
  1614 * proper handling of dangling sort hypotheses (at last!);
  1615 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1616 extra sort hypotheses that can be witnessed from the type signature;
  1617 the force_strip_shyps flag is gone, any remaining shyps are simply
  1618 left in the theorem (with a warning issued by strip_shyps_warning);
  1619 
  1620 
  1621 
  1622 New in Isabelle98-1 (October 1998)
  1623 ----------------------------------
  1624 
  1625 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1626 
  1627 * several changes of automated proof tools;
  1628 
  1629 * HOL: major changes to the inductive and datatype packages, including
  1630 some minor incompatibilities of theory syntax;
  1631 
  1632 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1633 called `inj_on';
  1634 
  1635 * HOL: removed duplicate thms in Arith:
  1636   less_imp_add_less  should be replaced by  trans_less_add1
  1637   le_imp_add_le      should be replaced by  trans_le_add1
  1638 
  1639 * HOL: unary minus is now overloaded (new type constraints may be
  1640 required);
  1641 
  1642 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1643 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1644 now taken as an integer constant.
  1645 
  1646 * Pure: ML function 'theory_of' renamed to 'theory';
  1647 
  1648 
  1649 *** Proof tools ***
  1650 
  1651 * Simplifier:
  1652   1. Asm_full_simp_tac is now more aggressive.
  1653      1. It will sometimes reorient premises if that increases their power to
  1654         simplify.
  1655      2. It does no longer proceed strictly from left to right but may also
  1656         rotate premises to achieve further simplification.
  1657      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1658      old Asm_full_simp_tac in that it does not rotate premises.
  1659   2. The simplifier now knows a little bit about nat-arithmetic.
  1660 
  1661 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1662 allows for selected deletion of wrappers, by introduction of names for
  1663 wrapper functionals.  This implies that addbefore, addSbefore,
  1664 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1665 and that adding two tactics with the same name overwrites the first
  1666 one (emitting a warning).
  1667   type wrapper = (int -> tactic) -> (int -> tactic)
  1668   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1669   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1670   delWrapper, delSWrapper: claset *  string            -> claset
  1671   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1672 
  1673 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1674 semantics; addbefore now affects only the unsafe part of step_tac
  1675 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1676 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1677 by Force_tac;
  1678 
  1679 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1680 compWrapper; added safe wrapper (and access functions for it);
  1681 
  1682 * HOL/split_all_tac is now much faster and fails if there is nothing
  1683 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1684 and the names of the automatically generated variables have changed.
  1685 split_all_tac has moved within claset() from unsafe wrappers to safe
  1686 wrappers, which means that !!-bound variables are split much more
  1687 aggressively, and safe_tac and clarify_tac now split such variables.
  1688 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1689 Note: the same holds for record_split_tac, which does the job of
  1690 split_all_tac for record fields.
  1691 
  1692 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1693 permanently to the default simpset using Addsplits just like
  1694 Addsimps. They can be removed via Delsplits just like
  1695 Delsimps. Lower-case versions are also available.
  1696 
  1697 * HOL/Simplifier: The rule split_if is now part of the default
  1698 simpset. This means that the simplifier will eliminate all occurrences
  1699 of if-then-else in the conclusion of a goal. To prevent this, you can
  1700 either remove split_if completely from the default simpset by
  1701 `Delsplits [split_if]' or remove it in a specific call of the
  1702 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1703 other case splitting rules to/from the default simpset: every datatype
  1704 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1705 t is the name of the datatype).
  1706 
  1707 * Classical reasoner / Simplifier combination: new force_tac (and
  1708 derivatives Force_tac, force) combines rewriting and classical
  1709 reasoning (and whatever other tools) similarly to auto_tac, but is
  1710 aimed to solve the given subgoal completely.
  1711 
  1712 
  1713 *** General ***
  1714 
  1715 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1716 and `goalw': the theory is no longer needed as an explicit argument -
  1717 the current theory context is used; assumptions are no longer returned
  1718 at the ML-level unless one of them starts with ==> or !!; it is
  1719 recommended to convert to these new commands using isatool fixgoal
  1720 (backup your sources first!);
  1721 
  1722 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1723 the current theory context, and 'theory' to lookup stored theories;
  1724 
  1725 * new theory section 'locale' for declaring constants, assumptions and
  1726 definitions that have local scope;
  1727 
  1728 * new theory section 'nonterminals' for purely syntactic types;
  1729 
  1730 * new theory section 'setup' for generic ML setup functions
  1731 (e.g. package initialization);
  1732 
  1733 * the distribution now includes Isabelle icons: see
  1734 lib/logo/isabelle-{small,tiny}.xpm;
  1735 
  1736 * isatool install - install binaries with absolute references to
  1737 ISABELLE_HOME/bin;
  1738 
  1739 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1740 
  1741 * print mode 'emacs' reserved for Isamode;
  1742 
  1743 * support multiple print (ast) translations per constant name;
  1744 
  1745 * theorems involving oracles are now printed with a suffixed [!];
  1746 
  1747 
  1748 *** HOL ***
  1749 
  1750 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1751 
  1752 * HOL/inductive package reorganized and improved: now supports mutual
  1753 definitions such as
  1754 
  1755   inductive EVEN ODD
  1756     intrs
  1757       null "0 : EVEN"
  1758       oddI "n : EVEN ==> Suc n : ODD"
  1759       evenI "n : ODD ==> Suc n : EVEN"
  1760 
  1761 new theorem list "elims" contains an elimination rule for each of the
  1762 recursive sets; inductive definitions now handle disjunctive premises
  1763 correctly (also ZF);
  1764 
  1765 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1766 "mutual_induct" no longer exists - the induction rule is always
  1767 contained in "induct";
  1768 
  1769 
  1770 * HOL/datatype package re-implemented and greatly improved: now
  1771 supports mutually recursive datatypes such as
  1772 
  1773   datatype
  1774     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1775             | SUM ('a aexp) ('a aexp)
  1776             | DIFF ('a aexp) ('a aexp)
  1777             | NUM 'a
  1778   and
  1779     'a bexp = LESS ('a aexp) ('a aexp)
  1780             | AND ('a bexp) ('a bexp)
  1781             | OR ('a bexp) ('a bexp)
  1782 
  1783 as well as indirectly recursive datatypes such as
  1784 
  1785   datatype
  1786     ('a, 'b) term = Var 'a
  1787                   | App 'b ((('a, 'b) term) list)
  1788 
  1789 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1790 induction on mutually / indirectly recursive datatypes.
  1791 
  1792 Primrec equations are now stored in theory and can be accessed via
  1793 <function_name>.simps.
  1794 
  1795 INCOMPATIBILITIES:
  1796 
  1797   - Theories using datatypes must now have theory Datatype as an
  1798     ancestor.
  1799   - The specific <typename>.induct_tac no longer exists - use the
  1800     generic induct_tac instead.
  1801   - natE has been renamed to nat.exhaust - use exhaust_tac
  1802     instead of res_inst_tac ... natE. Note that the variable
  1803     names in nat.exhaust differ from the names in natE, this
  1804     may cause some "fragile" proofs to fail.
  1805   - The theorems split_<typename>_case and split_<typename>_case_asm
  1806     have been renamed to <typename>.split and <typename>.split_asm.
  1807   - Since default sorts of type variables are now handled correctly,
  1808     some datatype definitions may have to be annotated with explicit
  1809     sort constraints.
  1810   - Primrec definitions no longer require function name and type
  1811     of recursive argument.
  1812 
  1813 Consider using isatool fixdatatype to adapt your theories and proof
  1814 scripts to the new package (backup your sources first!).
  1815 
  1816 
  1817 * HOL/record package: considerably improved implementation; now
  1818 includes concrete syntax for record types, terms, updates; theorems
  1819 for surjective pairing and splitting !!-bound record variables; proof
  1820 support is as follows:
  1821 
  1822   1) standard conversions (selectors or updates applied to record
  1823 constructor terms) are part of the standard simpset;
  1824 
  1825   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1826 made part of standard simpset and claset via addIffs;
  1827 
  1828   3) a tactic for record field splitting (record_split_tac) is part of
  1829 the standard claset (addSWrapper);
  1830 
  1831 To get a better idea about these rules you may retrieve them via
  1832 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1833 the name of your record type.
  1834 
  1835 The split tactic 3) conceptually simplifies by the following rule:
  1836 
  1837   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1838 
  1839 Thus any record variable that is bound by meta-all will automatically
  1840 blow up into some record constructor term, consequently the
  1841 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1842 solve record problems automatically.
  1843 
  1844 
  1845 * reorganized the main HOL image: HOL/Integ and String loaded by
  1846 default; theory Main includes everything;
  1847 
  1848 * automatic simplification of integer sums and comparisons, using cancellation;
  1849 
  1850 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1851 
  1852 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1853 
  1854 * many new identities for unions, intersections, set difference, etc.;
  1855 
  1856 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1857 called split_if, split_split, split_sum_case and split_nat_case (to go
  1858 with add/delsplits);
  1859 
  1860 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1861 (?x::unit) = (); this is made part of the default simpset, which COULD
  1862 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1863 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1864 unit_abs_eta_conv is added in order to counter the effect of
  1865 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1866 %u.f();
  1867 
  1868 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1869 makes more sense);
  1870 
  1871 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1872   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1873   disjointness reasoning but breaking a few old proofs.
  1874 
  1875 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1876 to 'converse' from 'inverse' (for compatibility with ZF and some
  1877 literature);
  1878 
  1879 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1880 the well-founded relation;
  1881 
  1882 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1883     Compl A.  The "Compl" syntax remains available as input syntax for this
  1884     release ONLY.
  1885 
  1886 * HOL/Update: new theory of function updates:
  1887     f(a:=b) == %x. if x=a then b else f x
  1888 may also be iterated as in f(a:=b,c:=d,...);
  1889 
  1890 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1891 
  1892 * HOL/List:
  1893   - new function list_update written xs[i:=v] that updates the i-th
  1894     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1895   - new function `upt' written [i..j(] which generates the list
  1896     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1897     bound write [i..j], which is a shorthand for [i..j+1(].
  1898   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1899 
  1900 * HOL/Arith:
  1901   - removed 'pred' (predecessor) function;
  1902   - generalized some theorems about n-1;
  1903   - many new laws about "div" and "mod";
  1904   - new laws about greatest common divisors (see theory ex/Primes);
  1905 
  1906 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1907 instead of "inverse";
  1908 
  1909 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1910   of the multiset ordering;
  1911 
  1912 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1913   (not included by default);
  1914 
  1915 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1916 
  1917 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1918   programs, i.e. different program variables may have different types.
  1919 
  1920 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1921   [previously, this check worked only if the rewrite rule was unconditional]
  1922   Now rew can involve either definitions or equalities (either == or =).
  1923 
  1924 
  1925 *** ZF ***
  1926 
  1927 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1928   only the theorems proved on ZF.ML;
  1929 
  1930 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1931   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1932   disjointness reasoning but breaking a few old proofs.
  1933 
  1934 * ZF/Update: new theory of function updates
  1935     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1936   may also be iterated as in f(a:=b,c:=d,...);
  1937 
  1938 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1939 
  1940 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1941   [previously, this check worked only if the rewrite rule was unconditional]
  1942   Now rew can involve either definitions or equalities (either == or =).
  1943 
  1944 * case_tac provided for compatibility with HOL
  1945     (like the old excluded_middle_tac, but with subgoals swapped)
  1946 
  1947 
  1948 *** Internal programming interfaces ***
  1949 
  1950 * Pure: several new basic modules made available for general use, see
  1951 also src/Pure/README;
  1952 
  1953 * improved the theory data mechanism to support encapsulation (data
  1954 kind name replaced by private Object.kind, acting as authorization
  1955 key); new type-safe user interface via functor TheoryDataFun; generic
  1956 print_data function becomes basically useless;
  1957 
  1958 * removed global_names compatibility flag -- all theory declarations
  1959 are qualified by default;
  1960 
  1961 * module Pure/Syntax now offers quote / antiquote translation
  1962 functions (useful for Hoare logic etc. with implicit dependencies);
  1963 see HOL/ex/Antiquote for an example use;
  1964 
  1965 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1966 cterm -> thm;
  1967 
  1968 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1969 subgoal;
  1970 
  1971 * Display.print_goals function moved to Locale.print_goals;
  1972 
  1973 * standard print function for goals supports current_goals_markers
  1974 variable for marking begin of proof, end of proof, start of goal; the
  1975 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1976 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  1977 for example;
  1978 
  1979 
  1980 
  1981 New in Isabelle98 (January 1998)
  1982 --------------------------------
  1983 
  1984 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1985 
  1986 * changed lexical syntax of terms / types: dots made part of long
  1987 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  1988 
  1989 * simpset (and claset) reference variable replaced by functions
  1990 simpset / simpset_ref;
  1991 
  1992 * no longer supports theory aliases (via merge) and non-trivial
  1993 implicit merge of thms' signatures;
  1994 
  1995 * most internal names of constants changed due to qualified names;
  1996 
  1997 * changed Pure/Sequence interface (see Pure/seq.ML);
  1998 
  1999 
  2000 *** General Changes ***
  2001 
  2002 * hierachically structured name spaces (for consts, types, axms, thms
  2003 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2004 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2005 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2006 long_names for fully qualified output names; NOTE: ML programs
  2007 (special tactics, packages etc.) referring to internal names may have
  2008 to be adapted to cope with fully qualified names; in case of severe
  2009 backward campatibility problems try setting 'global_names' at compile
  2010 time to have enrything declared within a flat name space; one may also
  2011 fine tune name declarations in theories via the 'global' and 'local'
  2012 section;
  2013 
  2014 * reimplemented the implicit simpset and claset using the new anytype
  2015 data filed in signatures; references simpset:simpset ref etc. are
  2016 replaced by functions simpset:unit->simpset and
  2017 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2018 to patch your ML files accordingly;
  2019 
  2020 * HTML output now includes theory graph data for display with Java
  2021 applet or isatool browser; data generated automatically via isatool
  2022 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2023 
  2024 * defs may now be conditional; improved rewrite_goals_tac to handle
  2025 conditional equations;
  2026 
  2027 * defs now admits additional type arguments, using TYPE('a) syntax;
  2028 
  2029 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2030 creates a new theory node; implicit merge of thms' signatures is
  2031 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2032 transfer:theory->thm->thm in (rare) cases;
  2033 
  2034 * improved handling of draft signatures / theories; draft thms (and
  2035 ctyps, cterms) are automatically promoted to real ones;
  2036 
  2037 * slightly changed interfaces for oracles: admit many per theory, named
  2038 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2039 
  2040 * print_goals: optional output of const types (set show_consts and
  2041 show_types);
  2042 
  2043 * improved output of warnings (###) and errors (***);
  2044 
  2045 * subgoal_tac displays a warning if the new subgoal has type variables;
  2046 
  2047 * removed old README and Makefiles;
  2048 
  2049 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2050 
  2051 * removed obsolete init_pps and init_database;
  2052 
  2053 * deleted the obsolete tactical STATE, which was declared by
  2054     fun STATE tacfun st = tacfun st st;
  2055 
  2056 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2057 (which abbreviates $HOME);
  2058 
  2059 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2060 use isatool fixseq to adapt your ML programs (this works for fully
  2061 qualified references to the Sequence structure only!);
  2062 
  2063 * use_thy no longer requires writable current directory; it always
  2064 reloads .ML *and* .thy file, if either one is out of date;
  2065 
  2066 
  2067 *** Classical Reasoner ***
  2068 
  2069 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2070 tactics that use classical reasoning to simplify a subgoal without
  2071 splitting it into several subgoals;
  2072 
  2073 * Safe_tac: like safe_tac but uses the default claset;
  2074 
  2075 
  2076 *** Simplifier ***
  2077 
  2078 * added simplification meta rules:
  2079     (asm_)(full_)simplify: simpset -> thm -> thm;
  2080 
  2081 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2082 logics (again);
  2083 
  2084 * added prems argument to simplification procedures;
  2085 
  2086 * HOL, FOL, ZF: added infix function `addsplits':
  2087   instead of `<simpset> setloop (split_tac <thms>)'
  2088   you can simply write `<simpset> addsplits <thms>'
  2089 
  2090 
  2091 *** Syntax ***
  2092 
  2093 * TYPE('a) syntax for type reflection terms;
  2094 
  2095 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2096 
  2097 * pretty printer: changed order of mixfix annotation preference (again!);
  2098 
  2099 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2100 
  2101 
  2102 *** HOL ***
  2103 
  2104 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2105   with `addloop' of the simplifier to faciliate case splitting in premises.
  2106 
  2107 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2108 
  2109 * HOL/Auth: new protocol proofs including some for the Internet
  2110   protocol TLS;
  2111 
  2112 * HOL/Map: new theory of `maps' a la VDM;
  2113 
  2114 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2115 cancelling out common nat summands from =, <, <= (in)equalities, or
  2116 differences; simplification procedures nat_cancel_factor for
  2117 cancelling common factor from =, <, <= (in)equalities over natural
  2118 sums; nat_cancel contains both kinds of procedures, it is installed by
  2119 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2120 
  2121 * HOL/simplifier: terms of the form
  2122   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2123   are rewritten to
  2124   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2125   and those of the form
  2126   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2127   are rewritten to
  2128   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2129 
  2130 * HOL/datatype
  2131   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2132 
  2133   P(t_case f1 ... fn x) =
  2134      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2135         ...
  2136        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2137      )
  2138 
  2139   and a theorem `split_t_case_asm' of the form
  2140 
  2141   P(t_case f1 ... fn x) =
  2142     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2143         ...
  2144        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2145      )
  2146   which can be added to a simpset via `addsplits'. The existing theorems
  2147   expand_list_case and expand_option_case have been renamed to
  2148   split_list_case and split_option_case.
  2149 
  2150 * HOL/Arithmetic:
  2151   - `pred n' is automatically converted to `n-1'.
  2152     Users are strongly encouraged not to use `pred' any longer,
  2153     because it will disappear altogether at some point.
  2154   - Users are strongly encouraged to write "0 < n" rather than
  2155     "n ~= 0". Theorems and proof tools have been modified towards this
  2156     `standard'.
  2157 
  2158 * HOL/Lists:
  2159   the function "set_of_list" has been renamed "set" (and its theorems too);
  2160   the function "nth" now takes its arguments in the reverse order and
  2161   has acquired the infix notation "!" as in "xs!n".
  2162 
  2163 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2164 
  2165 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2166   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2167 
  2168 * HOL/record: extensible records with schematic structural subtyping
  2169 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2170 still lacks various theorems and concrete record syntax;
  2171 
  2172 
  2173 *** HOLCF ***
  2174 
  2175 * removed "axioms" and "generated by" sections;
  2176 
  2177 * replaced "ops" section by extended "consts" section, which is capable of
  2178   handling the continuous function space "->" directly;
  2179 
  2180 * domain package:
  2181   . proves theorems immediately and stores them in the theory,
  2182   . creates hierachical name space,
  2183   . now uses normal mixfix annotations (instead of cinfix...),
  2184   . minor changes to some names and values (for consistency),
  2185   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2186   . separator between mutual domain defs: changed "," to "and",
  2187   . improved handling of sort constraints;  now they have to
  2188     appear on the left-hand side of the equations only;
  2189 
  2190 * fixed LAM <x,y,zs>.b syntax;
  2191 
  2192 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2193 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2194 
  2195 
  2196 *** FOL and ZF ***
  2197 
  2198 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2199   with `addloop' of the simplifier to faciliate case splitting in premises.
  2200 
  2201 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2202 in HOL, they strip ALL and --> from proved theorems;
  2203 
  2204 
  2205 
  2206 New in Isabelle94-8 (May 1997)
  2207 ------------------------------
  2208 
  2209 *** General Changes ***
  2210 
  2211 * new utilities to build / run / maintain Isabelle etc. (in parts
  2212 still somewhat experimental); old Makefiles etc. still functional;
  2213 
  2214 * new 'Isabelle System Manual';
  2215 
  2216 * INSTALL text, together with ./configure and ./build scripts;
  2217 
  2218 * reimplemented type inference for greater efficiency, better error
  2219 messages and clean internal interface;
  2220 
  2221 * prlim command for dealing with lots of subgoals (an easier way of
  2222 setting goals_limit);
  2223 
  2224 
  2225 *** Syntax ***
  2226 
  2227 * supports alternative (named) syntax tables (parser and pretty
  2228 printer); internal interface is provided by add_modesyntax(_i);
  2229 
  2230 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2231 be used in conjunction with the Isabelle symbol font; uses the
  2232 "symbols" syntax table;
  2233 
  2234 * added token_translation interface (may translate name tokens in
  2235 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2236 the current print_mode); IMPORTANT: user print translation functions
  2237 are responsible for marking newly introduced bounds
  2238 (Syntax.mark_boundT);
  2239 
  2240 * token translations for modes "xterm" and "xterm_color" that display
  2241 names in bold, underline etc. or colors (which requires a color
  2242 version of xterm);
  2243 
  2244 * infixes may now be declared with names independent of their syntax;
  2245 
  2246 * added typed_print_translation (like print_translation, but may
  2247 access type of constant);
  2248 
  2249 
  2250 *** Classical Reasoner ***
  2251 
  2252 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2253 some limitations.  Blast_tac...
  2254   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2255   + ignores elimination rules that don't have the correct format
  2256         (the conclusion MUST be a formula variable)
  2257   + ignores types, which can make HOL proofs fail
  2258   + rules must not require higher-order unification, e.g. apply_type in ZF
  2259     [message "Function Var's argument not a bound variable" relates to this]
  2260   + its proof strategy is more general but can actually be slower
  2261 
  2262 * substitution with equality assumptions no longer permutes other
  2263 assumptions;
  2264 
  2265 * minor changes in semantics of addafter (now called addaltern); renamed
  2266 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2267 (and access functions for it);
  2268 
  2269 * improved combination of classical reasoner and simplifier:
  2270   + functions for handling clasimpsets
  2271   + improvement of addss: now the simplifier is called _after_ the
  2272     safe steps.
  2273   + safe variant of addss called addSss: uses safe simplifications
  2274     _during_ the safe steps. It is more complete as it allows multiple
  2275     instantiations of unknowns (e.g. with slow_tac).
  2276 
  2277 *** Simplifier ***
  2278 
  2279 * added interface for simplification procedures (functions that
  2280 produce *proven* rewrite rules on the fly, depending on current
  2281 redex);
  2282 
  2283 * ordering on terms as parameter (used for ordered rewriting);
  2284 
  2285 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2286 
  2287 * the solver is now split into a safe and an unsafe part.
  2288 This should be invisible for the normal user, except that the
  2289 functions setsolver and addsolver have been renamed to setSolver and
  2290 addSolver; added safe_asm_full_simp_tac;
  2291 
  2292 
  2293 *** HOL ***
  2294 
  2295 * a generic induction tactic `induct_tac' which works for all datatypes and
  2296 also for type `nat';
  2297 
  2298 * a generic case distinction tactic `exhaust_tac' which works for all
  2299 datatypes and also for type `nat';
  2300 
  2301 * each datatype comes with a function `size';
  2302 
  2303 * patterns in case expressions allow tuple patterns as arguments to
  2304 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2305 
  2306 * primrec now also works with type nat;
  2307 
  2308 * recdef: a new declaration form, allows general recursive functions to be
  2309 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2310 
  2311 * the constant for negation has been renamed from "not" to "Not" to
  2312 harmonize with FOL, ZF, LK, etc.;
  2313 
  2314 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2315 infinite lists;
  2316 
  2317 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2318 
  2319 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2320 problems in commutative rings, using axiomatic type classes for + and *;
  2321 
  2322 * more examples in HOL/MiniML and HOL/Auth;
  2323 
  2324 * more default rewrite rules for quantifiers, union/intersection;
  2325 
  2326 * a new constant `arbitrary == @x.False';
  2327 
  2328 * HOLCF/IOA replaces old HOL/IOA;
  2329 
  2330 * HOLCF changes: derived all rules and arities
  2331   + axiomatic type classes instead of classes
  2332   + typedef instead of faking type definitions
  2333   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2334   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2335   + eliminated the types void, one, tr
  2336   + use unit lift and bool lift (with translations) instead of one and tr
  2337   + eliminated blift from Lift3.thy (use Def instead of blift)
  2338   all eliminated rules are derived as theorems --> no visible changes ;
  2339 
  2340 
  2341 *** ZF ***
  2342 
  2343 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2344 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2345 as ZF_cs addSIs [equalityI];
  2346 
  2347 
  2348 
  2349 New in Isabelle94-7 (November 96)
  2350 ---------------------------------
  2351 
  2352 * allowing negative levels (as offsets) in prlev and choplev;
  2353 
  2354 * super-linear speedup for large simplifications;
  2355 
  2356 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2357 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2358 FAIL); can suppress it using the command Delsimps (ex_simps @
  2359 all_simps); De Morgan laws are also now included, by default;
  2360 
  2361 * improved printing of ==>  :  ~:
  2362 
  2363 * new object-logic "Sequents" adds linear logic, while replacing LK
  2364 and Modal (thanks to Sara Kalvala);
  2365 
  2366 * HOL/Auth: correctness proofs for authentication protocols;
  2367 
  2368 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2369 examples on HOL/Auth);
  2370 
  2371 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2372 the rewriter and classical reasoner simultaneously;
  2373 
  2374 * function uresult no longer returns theorems in "standard" format;
  2375 regain previous version by: val uresult = standard o uresult;
  2376 
  2377 
  2378 
  2379 New in Isabelle94-6
  2380 -------------------
  2381 
  2382 * oracles -- these establish an interface between Isabelle and trusted
  2383 external reasoners, which may deliver results as theorems;
  2384 
  2385 * proof objects (in particular record all uses of oracles);
  2386 
  2387 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2388 
  2389 * "constdefs" section in theory files;
  2390 
  2391 * "primrec" section (HOL) no longer requires names;
  2392 
  2393 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2394 
  2395 
  2396 
  2397 New in Isabelle94-5
  2398 -------------------
  2399 
  2400 * reduced space requirements;
  2401 
  2402 * automatic HTML generation from theories;
  2403 
  2404 * theory files no longer require "..." (quotes) around most types;
  2405 
  2406 * new examples, including two proofs of the Church-Rosser theorem;
  2407 
  2408 * non-curried (1994) version of HOL is no longer distributed;
  2409 
  2410 
  2411 
  2412 New in Isabelle94-4
  2413 -------------------
  2414 
  2415 * greatly reduced space requirements;
  2416 
  2417 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2418 
  2419 * searchable theorem database (see the section "Retrieving theorems" on
  2420 page 8 of the Reference Manual);
  2421 
  2422 * new examples, including Grabczewski's monumental case study of the
  2423 Axiom of Choice;
  2424 
  2425 * The previous version of HOL renamed to Old_HOL;
  2426 
  2427 * The new version of HOL (previously called CHOL) uses a curried syntax
  2428 for functions.  Application looks like f a b instead of f(a,b);
  2429 
  2430 * Mutually recursive inductive definitions finally work in HOL;
  2431 
  2432 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2433 translates to the operator "split";
  2434 
  2435 
  2436 
  2437 New in Isabelle94-3
  2438 -------------------
  2439 
  2440 * new infix operator, addss, allowing the classical reasoner to
  2441 perform simplification at each step of its search.  Example:
  2442         fast_tac (cs addss ss)
  2443 
  2444 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2445 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2446 look like (a,b) instead of <a,b>;
  2447 
  2448 * PLEASE NOTE: CHOL will eventually replace HOL!
  2449 
  2450 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2451 It translates to the operator "split".  A new theory of integers is available;
  2452 
  2453 * In ZF, integer numerals now denote two's-complement binary integers.
  2454 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2455 
  2456 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2457 of the Axiom of Choice;
  2458 
  2459 
  2460 
  2461 New in Isabelle94-2
  2462 -------------------
  2463 
  2464 * Significantly faster resolution;
  2465 
  2466 * the different sections in a .thy file can now be mixed and repeated
  2467 freely;
  2468 
  2469 * Database of theorems for FOL, HOL and ZF.  New
  2470 commands including qed, qed_goal and bind_thm store theorems in the database.
  2471 
  2472 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2473 a given theory (thms_of), or find out what theory a theorem was proved in
  2474 (theory_of_thm);
  2475 
  2476 * Bugs fixed in the inductive definition and datatype packages;
  2477 
  2478 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2479 and HOL_dup_cs obsolete;
  2480 
  2481 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2482 have been removed;
  2483 
  2484 * Simpler definition of function space in ZF;
  2485 
  2486 * new results about cardinal and ordinal arithmetic in ZF;
  2487 
  2488 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2489 types;
  2490 
  2491 
  2492 $Id$