NEWS
author kleing
Sat Dec 06 07:52:17 2003 +0100 (2003-12-06)
changeset 14283 516358ca7b42
parent 14257 a7ef3f7588c5
child 14285 92ed032e83a1
permissions -rw-r--r--
moreover and also do not reset facts any more
     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: Macintosh and Windows line-breaks are now allowed in theory files.
    21 
    22 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    23   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    24   a normal (but invisible) letter. For multiple letter subscripts repeat 
    25   \<^isub> like this: x\<^isub>1\<^isub>2. 
    26 
    27 * Pure: Using new Isar command "finalconsts" (or the ML functions
    28   Theory.add_finals or Theory.add_finals_i) it is now possible to
    29   declare constants "final", which prevents their being given a definition
    30   later.  It is useful for constants whose behaviour is fixed axiomatically
    31   rather than definitionally, such as the meta-logic connectives.
    32 
    33 *** Isar ***
    34 
    35 * Tactic emulation methods ?rule_tac, cut_tac, subgoal_tac and thin_tac:
    36   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    37     locales are no longer forced to write Isar proof scripts.
    38     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    39     emulations.
    40   - INCOMPATIBILITY: names of variables to be instantiated may no
    41     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    42     This is consistent with the instantiation attribute "where".
    43 
    44 * Attributes "where" and "of":
    45   Now take type variables of instantiated theorem into account when reading
    46   the instantiation string.  This fixes a bug that caused instantiated
    47   theorems to have too special types in some circumstances.
    48 
    49 * Calculation commands "moreover" and "also":
    50   Do not reset facts ("this") any more.
    51 
    52 * Locales:
    53   - Goal statements involving the context element "includes" no longer
    54     generate theorems with internal delta predicates (those ending on
    55     "_axioms") in the premise.
    56     Resolve particular premise with <locale>.intro to obtain old form.
    57   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    58     specification and "includes" elements in goal statement.
    59   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    60     [intro?] and [elim?] (respectively) by default.
    61 
    62 * HOL: Tactic emulation methods induct_tac and case_tac understand static
    63   (Isar) contexts.
    64 
    65 *** HOL ***
    66 
    67 * Records:
    68   - Record types are now by default printed with their type abbreviation
    69     instead of the list of all field types. This can be configured via
    70     the reference "print_record_type_abbr".
    71   - Simproc "record_upd_simproc" for simplification of multiple updates added 
    72     (not enabled by default).
    73   - Tactic "record_split_simp_tac" to split and simplify records added.
    74  
    75 * 'specification' command added, allowing for definition by
    76   specification.  There is also an 'ax_specification' command that
    77   introduces the new constants axiomatically.
    78 
    79 * SET-Protocol: formalization and verification of the SET protocol suite;
    80 
    81 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
    82  defintions, thanks to Sava Krsti\'{c} and John Matthews.
    83 
    84 New in Isabelle2003 (May 2003)
    85 --------------------------------
    86 
    87 *** General ***
    88 
    89 * Provers/simplifier:
    90 
    91   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
    92     Assumptions are now subject to complete mutual simplification,
    93     not just from left to right. The simplifier now preserves
    94     the order of assumptions.
    95 
    96     Potential INCOMPATIBILITY:
    97 
    98     -- simp sometimes diverges where the old version did
    99        not, e.g. invoking simp on the goal
   100 
   101         [| P (f x); y = x; f x = f y |] ==> Q
   102 
   103        now gives rise to the infinite reduction sequence
   104 
   105         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   106 
   107        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   108        kind of problem.
   109 
   110     -- Tactics combining classical reasoner and simplification (such as auto)
   111        are also affected by this change, because many of them rely on
   112        simp. They may sometimes diverge as well or yield a different numbers
   113        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   114        in case of problems. Sometimes subsequent calls to the classical
   115        reasoner will fail because a preceeding call to the simplifier too
   116        eagerly simplified the goal, e.g. deleted redundant premises.
   117 
   118   - The simplifier trace now shows the names of the applied rewrite rules
   119 
   120   - You can limit the number of recursive invocations of the simplifier
   121     during conditional rewriting (where the simplifie tries to solve the
   122     conditions before applying the rewrite rule):
   123     ML "simp_depth_limit := n"
   124     where n is an integer. Thus you can force termination where previously
   125     the simplifier would diverge.
   126 
   127   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   128 
   129   - No longer aborts on failed congruence proof.  Instead, the
   130     congruence is ignored.
   131 
   132 * Pure: New generic framework for extracting programs from constructive
   133   proofs. See HOL/Extraction.thy for an example instantiation, as well
   134   as HOL/Extraction for some case studies.
   135 
   136 * Pure: The main goal of the proof state is no longer shown by default, only
   137 the subgoals. This behaviour is controlled by a new flag.
   138    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   139 (ML: Proof.show_main_goal).
   140 
   141 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   142 rules whose conclusion matches subgoal 1:
   143       PG menu: Isabelle/Isar -> Show me -> matching rules
   144 The rules are ordered by how closely they match the subgoal.
   145 In particular, rules that solve a subgoal outright are displayed first
   146 (or rather last, the way they are printed).
   147 (ML: ProofGeneral.print_intros())
   148 
   149 * Pure: New flag trace_unify_fail causes unification to print
   150 diagnostic information (PG: in trace buffer) when it fails. This is
   151 useful for figuring out why single step proofs like rule, erule or
   152 assumption failed.
   153 
   154 * Pure: Locale specifications now produce predicate definitions
   155 according to the body of text (covering assumptions modulo local
   156 definitions); predicate "loc_axioms" covers newly introduced text,
   157 while "loc" is cumulative wrt. all included locale expressions; the
   158 latter view is presented only on export into the global theory
   159 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   160 on the old view without predicates;
   161 
   162 * Pure: predefined locales "var" and "struct" are useful for sharing
   163 parameters (as in CASL, for example); just specify something like
   164 ``var x + var y + struct M'' as import;
   165 
   166 * Pure: improved thms_containing: proper indexing of facts instead of
   167 raw theorems; check validity of results wrt. current name space;
   168 include local facts of proof configuration (also covers active
   169 locales), cover fixed variables in index; may use "_" in term
   170 specification; an optional limit for the number of printed facts may
   171 be given (the default is 40);
   172 
   173 * Pure: disallow duplicate fact bindings within new-style theory files
   174 (batch-mode only);
   175 
   176 * Provers: improved induct method: assumptions introduced by case
   177 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   178 the goal statement); "foo" still refers to all facts collectively;
   179 
   180 * Provers: the function blast.overloaded has been removed: all constants
   181 are regarded as potentially overloaded, which improves robustness in exchange
   182 for slight decrease in efficiency;
   183 
   184 * Provers/linorder: New generic prover for transitivity reasoning over
   185 linear orders.  Note: this prover is not efficient!
   186 
   187 * Isar: preview of problems to finish 'show' now produce an error
   188 rather than just a warning (in interactive mode);
   189 
   190 
   191 *** HOL ***
   192 
   193 * arith(_tac)
   194 
   195  - Produces a counter example if it cannot prove a goal.
   196    Note that the counter example may be spurious if the goal is not a formula
   197    of quantifier-free linear arithmetic.
   198    In ProofGeneral the counter example appears in the trace buffer.
   199 
   200  - Knows about div k and mod k where k is a numeral of type nat or int.
   201 
   202  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   203    linear arithmetic fails. This takes account of quantifiers and divisibility.
   204    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   205 
   206 * simp's arithmetic capabilities have been enhanced a bit: it now
   207 takes ~= in premises into account (by performing a case split);
   208 
   209 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   210 are distributed over a sum of terms;
   211 
   212 * New tactic "trans_tac" and method "trans" instantiate
   213 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   214 "<=", "<" and "="). 
   215 
   216 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   217 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   218 
   219 * 'typedef' command has new option "open" to suppress the set
   220 definition;
   221 
   222 * functions Min and Max on finite sets have been introduced (theory
   223 Finite_Set);
   224 
   225 * attribute [symmetric] now works for relations as well; it turns
   226 (x,y) : R^-1 into (y,x) : R, and vice versa;
   227 
   228 * induct over a !!-quantified statement (say !!x1..xn):
   229   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   230 
   231 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   232 %x. None. Warning: empty_def now refers to the previously hidden definition
   233 of the empty set.
   234 
   235 * Algebra: formalization of classical algebra.  Intended as base for
   236 any algebraic development in Isabelle.  Currently covers group theory
   237 (up to Sylow's theorem) and ring theory (Universal Property of
   238 Univariate Polynomials).  Contributions welcome;
   239 
   240 * GroupTheory: deleted, since its material has been moved to Algebra;
   241 
   242 * Complex: new directory of the complex numbers with numeric constants, 
   243 nonstandard complex numbers, and some complex analysis, standard and 
   244 nonstandard (Jacques Fleuriot);
   245 
   246 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   247 
   248 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   249 Fleuriot);
   250 
   251 * Real/HahnBanach: updated and adapted to locales;
   252 
   253 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   254 Gray and Kramer);
   255 
   256 * UNITY: added the Meier-Sanders theory of progress sets;
   257 
   258 * MicroJava: bytecode verifier and lightweight bytecode verifier
   259 as abstract algorithms, instantiated to the JVM;
   260 
   261 * Bali: Java source language formalization. Type system, operational
   262 semantics, axiomatic semantics. Supported language features:
   263 classes, interfaces, objects,virtual methods, static methods,
   264 static/instance fields, arrays, access modifiers, definite
   265 assignment, exceptions.
   266 
   267 
   268 *** ZF ***
   269 
   270 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   271 universe, etc.);
   272 
   273 * Main ZF: virtually all theories converted to new-style format;
   274 
   275 
   276 *** ML ***
   277 
   278 * Pure: Tactic.prove provides sane interface for internal proofs;
   279 omits the infamous "standard" operation, so this is more appropriate
   280 than prove_goalw_cterm in many situations (e.g. in simprocs);
   281 
   282 * Pure: improved error reporting of simprocs;
   283 
   284 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   285 up simprocs;
   286 
   287 
   288 *** Document preparation ***
   289 
   290 * uses \par instead of \\ for line breaks in theory text. This may
   291 shift some page breaks in large documents. To get the old behaviour
   292 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   293 
   294 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   295 other packages
   296 
   297 * \<euro> now needs package babel/greek instead of marvosym (which
   298 broke \Rightarrow)
   299 
   300 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   301 textcomp package)
   302 
   303 
   304 New in Isabelle2002 (March 2002)
   305 --------------------------------
   306 
   307 *** Document preparation ***
   308 
   309 * greatly simplified document preparation setup, including more
   310 graceful interpretation of isatool usedir -i/-d/-D options, and more
   311 instructive isatool mkdir; users should basically be able to get
   312 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   313 users may run a separate document processing stage manually like this:
   314 "isatool usedir -D output HOL Test && isatool document Test/output";
   315 
   316 * theory dependency graph may now be incorporated into documents;
   317 isatool usedir -g true will produce session_graph.eps/.pdf for use
   318 with \includegraphics of LaTeX;
   319 
   320 * proper spacing of consecutive markup elements, especially text
   321 blocks after section headings;
   322 
   323 * support bold style (for single symbols only), input syntax is like
   324 this: "\<^bold>\<alpha>" or "\<^bold>A";
   325 
   326 * \<bullet> is now output as bold \cdot by default, which looks much
   327 better in printed text;
   328 
   329 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   330 note that these symbols are currently unavailable in Proof General /
   331 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   332 
   333 * isatool latex no longer depends on changed TEXINPUTS, instead
   334 isatool document copies the Isabelle style files to the target
   335 location;
   336 
   337 
   338 *** Isar ***
   339 
   340 * Pure/Provers: improved proof by cases and induction;
   341   - 'case' command admits impromptu naming of parameters (such as
   342     "case (Suc n)");
   343   - 'induct' method divinates rule instantiation from the inductive
   344     claim; no longer requires excessive ?P bindings for proper
   345     instantiation of cases;
   346   - 'induct' method properly enumerates all possibilities of set/type
   347     rules; as a consequence facts may be also passed through *type*
   348     rules without further ado;
   349   - 'induct' method now derives symbolic cases from the *rulified*
   350     rule (before it used to rulify cases stemming from the internal
   351     atomized version); this means that the context of a non-atomic
   352     statement becomes is included in the hypothesis, avoiding the
   353     slightly cumbersome show "PROP ?case" form;
   354   - 'induct' may now use elim-style induction rules without chaining
   355     facts, using ``missing'' premises from the goal state; this allows
   356     rules stemming from inductive sets to be applied in unstructured
   357     scripts, while still benefitting from proper handling of non-atomic
   358     statements; NB: major inductive premises need to be put first, all
   359     the rest of the goal is passed through the induction;
   360   - 'induct' proper support for mutual induction involving non-atomic
   361     rule statements (uses the new concept of simultaneous goals, see
   362     below);
   363   - append all possible rule selections, but only use the first
   364     success (no backtracking);
   365   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   366   - undeclared rule case names default to numbers 1, 2, 3, ...;
   367   - added 'print_induct_rules' (covered by help item in recent Proof
   368     General versions);
   369   - moved induct/cases attributes to Pure, methods to Provers;
   370   - generic method setup instantiated for FOL and HOL;
   371 
   372 * Pure: support multiple simultaneous goal statements, for example
   373 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   374 meta-level mechanism, this acts as if several individual goals had
   375 been stated separately; in particular common proof methods need to be
   376 repeated in order to cover all claims; note that a single elimination
   377 step is *not* sufficient to establish the two conjunctions, so this
   378 fails:
   379 
   380   assume "A & B" then have A and B ..   (*".." fails*)
   381 
   382 better use "obtain" in situations as above; alternative refer to
   383 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   384 
   385 * Pure: proper integration with ``locales''; unlike the original
   386 version by Florian Kammüller, Isar locales package high-level proof
   387 contexts rather than raw logical ones (e.g. we admit to include
   388 attributes everywhere); operations on locales include merge and
   389 rename; support for implicit arguments (``structures''); simultaneous
   390 type-inference over imports and text; see also HOL/ex/Locales.thy for
   391 some examples;
   392 
   393 * Pure: the following commands have been ``localized'', supporting a
   394 target locale specification "(in name)": 'lemma', 'theorem',
   395 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   396 stored both within the locale and at the theory level (exported and
   397 qualified by the locale name);
   398 
   399 * Pure: theory goals may now be specified in ``long'' form, with
   400 ad-hoc contexts consisting of arbitrary locale elements. for example
   401 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   402 definitions may be given, too); the result is a meta-level rule with
   403 the context elements being discharged in the obvious way;
   404 
   405 * Pure: new proof command 'using' allows to augment currently used
   406 facts after a goal statement ('using' is syntactically analogous to
   407 'apply', but acts on the goal's facts only); this allows chained facts
   408 to be separated into parts given before and after a claim, as in
   409 ``from a and b have C using d and e <proof>'';
   410 
   411 * Pure: renamed "antecedent" case to "rule_context";
   412 
   413 * Pure: new 'judgment' command records explicit information about the
   414 object-logic embedding (used by several tools internally); no longer
   415 use hard-wired "Trueprop";
   416 
   417 * Pure: added 'corollary' command;
   418 
   419 * Pure: fixed 'token_translation' command;
   420 
   421 * Pure: removed obsolete 'exported' attribute;
   422 
   423 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   424 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   425 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   426 
   427 * Pure: method 'atomize' presents local goal premises as object-level
   428 statements (atomic meta-level propositions); setup controlled via
   429 rewrite rules declarations of 'atomize' attribute; example
   430 application: 'induct' method with proper rule statements in improper
   431 proof *scripts*;
   432 
   433 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   434 now consider the syntactic context of assumptions, giving a better
   435 chance to get type-inference of the arguments right (this is
   436 especially important for locales);
   437 
   438 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   439 mode;
   440 
   441 * Pure/obtain: the formal conclusion "thesis", being marked as
   442 ``internal'', may no longer be reference directly in the text;
   443 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   444 situations;
   445 
   446 * Pure: generic 'sym' attribute which declares a rule both as pure
   447 'elim?' and for the 'symmetric' operation;
   448 
   449 * Pure: marginal comments ``--'' may now occur just anywhere in the
   450 text; the fixed correlation with particular command syntax has been
   451 discontinued;
   452 
   453 * Pure: new method 'rules' is particularly well-suited for proof
   454 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   455 but often produces more compact proof terms with less detours;
   456 
   457 * Pure/Provers/classical: simplified integration with pure rule
   458 attributes and methods; the classical "intro?/elim?/dest?"
   459 declarations coincide with the pure ones; the "rule" method no longer
   460 includes classically swapped intros; "intro" and "elim" methods no
   461 longer pick rules from the context; also got rid of ML declarations
   462 AddXIs/AddXEs/AddXDs; all of this has some potential for
   463 INCOMPATIBILITY;
   464 
   465 * Provers/classical: attribute 'swapped' produces classical inversions
   466 of introduction rules;
   467 
   468 * Provers/simplifier: 'simplified' attribute may refer to explicit
   469 rules instead of full simplifier context; 'iff' attribute handles
   470 conditional rules;
   471 
   472 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   473 
   474 * HOL: 'recdef' now fails on unfinished automated proofs, use
   475 "(permissive)" option to recover old behavior;
   476 
   477 * HOL: 'inductive' no longer features separate (collective) attributes
   478 for 'intros' (was found too confusing);
   479 
   480 * HOL: properly declared induction rules less_induct and
   481 wf_induct_rule;
   482 
   483 
   484 *** HOL ***
   485 
   486 * HOL: moved over to sane numeral syntax; the new policy is as
   487 follows:
   488 
   489   - 0 and 1 are polymorphic constants, which are defined on any
   490   numeric type (nat, int, real etc.);
   491 
   492   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   493   binary representation internally;
   494 
   495   - type nat has special constructor Suc, and generally prefers Suc 0
   496   over 1::nat and Suc (Suc 0) over 2::nat;
   497 
   498 This change may cause significant problems of INCOMPATIBILITY; here
   499 are some hints on converting existing sources:
   500 
   501   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   502   entities, so expressions involving "-" (unary or binary minus) need
   503   to be spaced properly;
   504 
   505   - existing occurrences of "1" may need to be constraint "1::nat" or
   506   even replaced by Suc 0; similar for old "2";
   507 
   508   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   509 
   510   - remove all special provisions on numerals in proofs;
   511 
   512 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   513 representation (depends on bin_arith_simps in the default context);
   514 
   515 * HOL: symbolic syntax for x^2 (numeral 2);
   516 
   517 * HOL: the class of all HOL types is now called "type" rather than
   518 "term"; INCOMPATIBILITY, need to adapt references to this type class
   519 in axclass/classes, instance/arities, and (usually rare) occurrences
   520 in typings (of consts etc.); internally the class is called
   521 "HOL.type", ML programs should refer to HOLogic.typeS;
   522 
   523 * HOL/record package improvements:
   524   - new derived operations "fields" to build a partial record section,
   525     "extend" to promote a fixed record to a record scheme, and
   526     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   527     declared as simp by default;
   528   - shared operations ("more", "fields", etc.) now need to be always
   529     qualified) --- potential INCOMPATIBILITY;
   530   - removed "make_scheme" operations (use "make" with "extend") --
   531     INCOMPATIBILITY;
   532   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   533   - provides cases/induct rules for use with corresponding Isar
   534     methods (for concrete records, record schemes, concrete more
   535     parts, and schematic more parts -- in that order);
   536   - internal definitions directly based on a light-weight abstract
   537     theory of product types over typedef rather than datatype;
   538 
   539 * HOL: generic code generator for generating executable ML code from
   540 specifications; specific support for HOL constructs such as inductive
   541 datatypes and sets, as well as recursive functions; can be invoked
   542 via 'generate_code' theory section;
   543 
   544 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   545 
   546 * HOL: consolidated and renamed several theories.  In particular:
   547 	Ord.thy has been absorbed into HOL.thy
   548 	String.thy has been absorbed into List.thy
   549  
   550 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   551 (beware of argument permutation!);
   552 
   553 * HOL: linorder_less_split superseded by linorder_cases;
   554 
   555 * HOL/List: "nodups" renamed to "distinct";
   556 
   557 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   558 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   559   - Ex_def has changed, now need to use some_eq_ex
   560 
   561 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   562 in this (rare) case use:
   563 
   564   delSWrapper "split_all_tac"
   565   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   566 
   567 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   568 MAY FAIL;
   569 
   570 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   571 Isabelle's type classes, ^ on functions and relations has too general
   572 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   573 necessary to attach explicit type constraints;
   574 
   575 * HOL/Relation: the prefix name of the infix "O" has been changed from
   576 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   577 renamed accordingly (eg "compI" -> "rel_compI").
   578 
   579 * HOL: syntax translations now work properly with numerals and records
   580 expressions;
   581 
   582 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   583 of "lam" -- INCOMPATIBILITY;
   584 
   585 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   586 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   587 renamed "Product_Type.unit";
   588 
   589 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   590 
   591 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   592 the "cases" method);
   593 
   594 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   595 Florian Kammüller);
   596 
   597 * HOL/IMP: updated and converted to new-style theory format; several
   598 parts turned into readable document, with proper Isar proof texts and
   599 some explanations (by Gerwin Klein);
   600 
   601 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   602 
   603 * HOL-Hyperreal is now a logic image;
   604 
   605 
   606 *** HOLCF ***
   607 
   608 * Isar: consts/constdefs supports mixfix syntax for continuous
   609 operations;
   610 
   611 * Isar: domain package adapted to new-style theory format, e.g. see
   612 HOLCF/ex/Dnat.thy;
   613 
   614 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   615 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   616 lift.induct_tac, always use UU instead of Undef;
   617 
   618 * HOLCF/IMP: updated and converted to new-style theory;
   619 
   620 
   621 *** ZF ***
   622 
   623 * Isar: proper integration of logic-specific tools and packages,
   624 including theory commands '(co)inductive', '(co)datatype',
   625 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   626 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   627 
   628 * theory Main no longer includes AC; for the Axiom of Choice, base
   629 your theory on Main_ZFC;
   630 
   631 * the integer library now covers quotients and remainders, with many
   632 laws relating division to addition, multiplication, etc.;
   633 
   634 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   635 typeless version of the formalism;
   636 
   637 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   638 format;
   639 
   640 * ZF/Induct: new directory for examples of inductive definitions,
   641 including theory Multiset for multiset orderings; converted to
   642 new-style theory format;
   643 
   644 * ZF: many new theorems about lists, ordinals, etc.;
   645 
   646 
   647 *** General ***
   648 
   649 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   650 variable proof controls level of detail: 0 = no proofs (only oracle
   651 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   652 also ref manual for further ML interfaces;
   653 
   654 * Pure/axclass: removed obsolete ML interface
   655 goal_subclass/goal_arity;
   656 
   657 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   658 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   659 separate tokens, so expressions involving minus need to be spaced
   660 properly;
   661 
   662 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   663 rather than "infixl" or "infixr";
   664 
   665 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   666 sort constraint specifications in type inference; e.g. "x::_::foo"
   667 ensures that the type of "x" is of sort "foo" (but not necessarily a
   668 type variable);
   669 
   670 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   671 control output of nested => (types); the default behavior is
   672 "type_brackets";
   673 
   674 * Pure/syntax: builtin parse translation for "_constify" turns valued
   675 tokens into AST constants;
   676 
   677 * Pure/syntax: prefer later declarations of translations and print
   678 translation functions; potential INCOMPATIBILITY: need to reverse
   679 multiple declarations for same syntax element constant;
   680 
   681 * Pure/show_hyps reset by default (in accordance to existing Isar
   682 practice);
   683 
   684 * Provers/classical: renamed addaltern to addafter, addSaltern to
   685 addSafter;
   686 
   687 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   688 as well;
   689 
   690 * system: tested support for MacOS X; should be able to get Isabelle +
   691 Proof General to work in a plain Terminal after installing Poly/ML
   692 (e.g. from the Isabelle distribution area) and GNU bash alone
   693 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   694 support requires further installations, e.g. from
   695 http://fink.sourceforge.net/);
   696 
   697 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   698 
   699 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   700 of 40 MB), cf. ML_OPTIONS;
   701 
   702 * system: Proof General keywords specification is now part of the
   703 Isabelle distribution (see etc/isar-keywords.el);
   704 
   705 * system: support for persistent Proof General sessions (refrain from
   706 outdating all loaded theories on startup); user may create writable
   707 logic images like this: ``isabelle -q HOL Test'';
   708 
   709 * system: smart selection of Isabelle process versus Isabelle
   710 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   711 run both "isabelle" and "Isabelle" even if file names are badly
   712 damaged (executable inspects the case of the first letter of its own
   713 name); added separate "isabelle-process" and "isabelle-interface";
   714 
   715 * system: refrain from any attempt at filtering input streams; no
   716 longer support ``8bit'' encoding of old isabelle font, instead proper
   717 iso-latin characters may now be used; the related isatools
   718 "symbolinput" and "nonascii" have disappeared as well;
   719 
   720 * system: removed old "xterm" interface (the print modes "xterm" and
   721 "xterm_color" are still available for direct use in a suitable
   722 terminal);
   723 
   724 
   725 
   726 New in Isabelle99-2 (February 2001)
   727 -----------------------------------
   728 
   729 *** Overview of INCOMPATIBILITIES ***
   730 
   731 * HOL: please note that theories in the Library and elsewhere often use the
   732 new-style (Isar) format; to refer to their theorems in an ML script you must
   733 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   734 
   735 * HOL: inductive package no longer splits induction rule aggressively,
   736 but only as far as specified by the introductions given; the old
   737 format may be recovered via ML function complete_split_rule or attribute
   738 'split_rule (complete)';
   739 
   740 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   741 gfp_Tarski to gfp_unfold;
   742 
   743 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   744 
   745 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   746 relation); infix "^^" has been renamed "``"; infix "``" has been
   747 renamed "`"; "univalent" has been renamed "single_valued";
   748 
   749 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   750 operation;
   751 
   752 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   753 
   754 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   755 
   756 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   757 consequence, it is no longer monotonic wrt. the local goal context
   758 (which is now passed through the inductive cases);
   759 
   760 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   761 \<gg> to \<ggreater>;
   762 
   763 
   764 *** Document preparation ***
   765 
   766 * \isabellestyle{NAME} selects version of Isabelle output (currently
   767 available: are "it" for near math-mode best-style output, "sl" for
   768 slanted text style, and "tt" for plain type-writer; if no
   769 \isabellestyle command is given, output is according to slanted
   770 type-writer);
   771 
   772 * support sub/super scripts (for single symbols only), input syntax is
   773 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   774 
   775 * some more standard symbols; see Appendix A of the system manual for
   776 the complete list of symbols defined in isabellesym.sty;
   777 
   778 * improved isabelle style files; more abstract symbol implementation
   779 (should now use \isamath{...} and \isatext{...} in custom symbol
   780 definitions);
   781 
   782 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   783 state; Note that presentation of goal states does not conform to
   784 actual human-readable proof documents.  Please do not include goal
   785 states into document output unless you really know what you are doing!
   786 
   787 * proper indentation of antiquoted output with proportional LaTeX
   788 fonts;
   789 
   790 * no_document ML operator temporarily disables LaTeX document
   791 generation;
   792 
   793 * isatool unsymbolize tunes sources for plain ASCII communication;
   794 
   795 
   796 *** Isar ***
   797 
   798 * Pure: Isar now suffers initial goal statements to contain unbound
   799 schematic variables (this does not conform to actual readable proof
   800 documents, due to unpredictable outcome and non-compositional proof
   801 checking); users who know what they are doing may use schematic goals
   802 for Prolog-style synthesis of proven results;
   803 
   804 * Pure: assumption method (an implicit finishing) now handles actual
   805 rules as well;
   806 
   807 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   808 initial goal, declare "that" only as Pure intro (only for single
   809 steps); the "that" rule assumption may now be involved in implicit
   810 finishing, thus ".." becomes a feasible for trivial obtains;
   811 
   812 * Pure: default proof step now includes 'intro_classes'; thus trivial
   813 instance proofs may be performed by "..";
   814 
   815 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   816 statements as well;
   817 
   818 * Pure: more robust selection of calculational rules;
   819 
   820 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   821 rule (as well as the assumption rule);
   822 
   823 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   824 lemmas, using the graph browser tool;
   825 
   826 * Pure: predict failure of "show" in interactive mode;
   827 
   828 * Pure: 'thms_containing' now takes actual terms as arguments;
   829 
   830 * HOL: improved method 'induct' --- now handles non-atomic goals
   831 (potential INCOMPATIBILITY); tuned error handling;
   832 
   833 * HOL: cases and induct rules now provide explicit hints about the
   834 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   835 any remaining facts are inserted into the goal verbatim;
   836 
   837 * HOL: local contexts (aka cases) may now contain term bindings as
   838 well; the 'cases' and 'induct' methods new provide a ?case binding for
   839 the result to be shown in each case;
   840 
   841 * HOL: added 'recdef_tc' command;
   842 
   843 * isatool convert assists in eliminating legacy ML scripts;
   844 
   845 
   846 *** HOL ***
   847 
   848 * HOL/Library: a collection of generic theories to be used together
   849 with main HOL; the theory loader path already includes this directory
   850 by default; the following existing theories have been moved here:
   851 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   852 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   853 
   854 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   855 modelling and verification task performed in Isabelle/HOL +
   856 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   857 
   858 * HOL/Algebra: special summation operator SUM no longer exists, it has
   859 been replaced by setsum; infix 'assoc' now has priority 50 (like
   860 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   861 'domain', this makes the theory consistent with mathematical
   862 literature;
   863 
   864 * HOL basics: added overloaded operations "inverse" and "divide"
   865 (infix "/"), syntax for generic "abs" operation, generic summation
   866 operator \<Sum>;
   867 
   868 * HOL/typedef: simplified package, provide more useful rules (see also
   869 HOL/subset.thy);
   870 
   871 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   872 now expressed as a proper nested rule (old-style tactic scripts may
   873 require atomize_strip_tac to cope with non-atomic premises);
   874 
   875 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   876 to "split_conv" (old name still available for compatibility);
   877 
   878 * HOL: improved concrete syntax for strings (e.g. allows translation
   879 rules with string literals);
   880 
   881 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   882  and Fleuriot's mechanization of analysis, including the transcendental
   883  functions for the reals;
   884 
   885 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   886 
   887 
   888 *** CTT ***
   889 
   890 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   891 "lam" is displayed as TWO lambda-symbols
   892 
   893 * CTT: theory Main now available, containing everything (that is, Bool
   894 and Arith);
   895 
   896 
   897 *** General ***
   898 
   899 * Pure: the Simplifier has been implemented properly as a derived rule
   900 outside of the actual kernel (at last!); the overall performance
   901 penalty in practical applications is about 50%, while reliability of
   902 the Isabelle inference kernel has been greatly improved;
   903 
   904 * print modes "brackets" and "no_brackets" control output of nested =>
   905 (types) and ==> (props); the default behaviour is "brackets";
   906 
   907 * Provers: fast_tac (and friends) now handle actual object-logic rules
   908 as assumptions as well;
   909 
   910 * system: support Poly/ML 4.0;
   911 
   912 * system: isatool install handles KDE version 1 or 2;
   913 
   914 
   915 
   916 New in Isabelle99-1 (October 2000)
   917 ----------------------------------
   918 
   919 *** Overview of INCOMPATIBILITIES ***
   920 
   921 * HOL: simplification of natural numbers is much changed; to partly
   922 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
   923 issue the following ML commands:
   924 
   925   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
   926   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
   927 
   928 * HOL: simplification no longer dives into case-expressions; this is
   929 controlled by "t.weak_case_cong" for each datatype t;
   930 
   931 * HOL: nat_less_induct renamed to less_induct;
   932 
   933 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
   934 fixsome to patch .thy and .ML sources automatically;
   935 
   936   select_equality  -> some_equality
   937   select_eq_Ex     -> some_eq_ex
   938   selectI2EX       -> someI2_ex
   939   selectI2         -> someI2
   940   selectI          -> someI
   941   select1_equality -> some1_equality
   942   Eps_sym_eq       -> some_sym_eq_trivial
   943   Eps_eq           -> some_eq_trivial
   944 
   945 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
   946 
   947 * HOL: removed obsolete theorem binding expand_if (refer to split_if
   948 instead);
   949 
   950 * HOL: the recursion equations generated by 'recdef' are now called
   951 f.simps instead of f.rules;
   952 
   953 * HOL: qed_spec_mp now also handles bounded ALL as well;
   954 
   955 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
   956 sometimes be needed;
   957 
   958 * HOL: the constant for "f``x" is now "image" rather than "op ``";
   959 
   960 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
   961 
   962 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
   963 product is now "<*>" instead of "Times"; the lexicographic product is
   964 now "<*lex*>" instead of "**";
   965 
   966 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
   967 of main HOL, but was unused); better use HOL's datatype package;
   968 
   969 * HOL: removed "symbols" syntax for constant "override" of theory Map;
   970 the old syntax may be recovered as follows:
   971 
   972   syntax (symbols)
   973     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
   974       (infixl "\\<oplus>" 100)
   975 
   976 * HOL/Real: "rabs" replaced by overloaded "abs" function;
   977 
   978 * HOL/ML: even fewer consts are declared as global (see theories Ord,
   979 Lfp, Gfp, WF); this only affects ML packages that refer to const names
   980 internally;
   981 
   982 * HOL and ZF: syntax for quotienting wrt an equivalence relation
   983 changed from A/r to A//r;
   984 
   985 * ZF: new treatment of arithmetic (nat & int) may break some old
   986 proofs;
   987 
   988 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
   989 rulify -> rule_format, elimify -> elim_format, ...);
   990 
   991 * Isar/Provers: intro/elim/dest attributes changed; renamed
   992 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
   993 should have to change intro!! to intro? only); replaced "delrule" by
   994 "rule del";
   995 
   996 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
   997 
   998 * Provers: strengthened force_tac by using new first_best_tac;
   999 
  1000 * LaTeX document preparation: several changes of isabelle.sty (see
  1001 lib/texinputs);
  1002 
  1003 
  1004 *** Document preparation ***
  1005 
  1006 * formal comments (text blocks etc.) in new-style theories may now
  1007 contain antiquotations of thm/prop/term/typ/text to be presented
  1008 according to latex print mode; concrete syntax is like this:
  1009 @{term[show_types] "f(x) = a + x"};
  1010 
  1011 * isatool mkdir provides easy setup of Isabelle session directories,
  1012 including proper document sources;
  1013 
  1014 * generated LaTeX sources are now deleted after successful run
  1015 (isatool document -c); may retain a copy somewhere else via -D option
  1016 of isatool usedir;
  1017 
  1018 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1019 style files, achieving self-contained LaTeX sources and simplifying
  1020 LaTeX debugging;
  1021 
  1022 * old-style theories now produce (crude) LaTeX output as well;
  1023 
  1024 * browser info session directories are now self-contained (may be put
  1025 on WWW server seperately); improved graphs of nested sessions; removed
  1026 graph for 'all sessions';
  1027 
  1028 * several improvements in isabelle style files; \isabellestyle{it}
  1029 produces fake math mode output; \isamarkupheader is now \section by
  1030 default; see lib/texinputs/isabelle.sty etc.;
  1031 
  1032 
  1033 *** Isar ***
  1034 
  1035 * Isar/Pure: local results and corresponding term bindings are now
  1036 subject to Hindley-Milner polymorphism (similar to ML); this
  1037 accommodates incremental type-inference very nicely;
  1038 
  1039 * Isar/Pure: new derived language element 'obtain' supports
  1040 generalized existence reasoning;
  1041 
  1042 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1043 support accumulation of results, without applying any rules yet;
  1044 useful to collect intermediate results without explicit name
  1045 references, and for use with transitivity rules with more than 2
  1046 premises;
  1047 
  1048 * Isar/Pure: scalable support for case-analysis type proofs: new
  1049 'case' language element refers to local contexts symbolically, as
  1050 produced by certain proof methods; internally, case names are attached
  1051 to theorems as "tags";
  1052 
  1053 * Isar/Pure: theory command 'hide' removes declarations from
  1054 class/type/const name spaces;
  1055 
  1056 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1057 indicate potential overloading;
  1058 
  1059 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1060 
  1061 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1062 "{a,b,c}" instead of {a,b,c};
  1063 
  1064 * Isar/Pure now provides its own version of intro/elim/dest
  1065 attributes; useful for building new logics, but beware of confusion
  1066 with the version in Provers/classical;
  1067 
  1068 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1069 case name 'antecedent';
  1070 
  1071 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1072 to the current context is now done automatically);
  1073 
  1074 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1075 for definining proof methods in ML;
  1076 
  1077 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1078 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1079 most cases, one should have to change intro!! to intro? only);
  1080 replaced "delrule" by "rule del";
  1081 
  1082 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1083 'symmetric' attribute (the latter supercedes [RS sym]);
  1084 
  1085 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1086 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1087 well (including splits);
  1088 
  1089 * Isar/Provers: Simplifier and Classical methods now support all kind
  1090 of modifiers used in the past, including 'cong', 'iff', etc.
  1091 
  1092 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1093 of Simplifier and Classical reasoner);
  1094 
  1095 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1096 now support named cases; major packages (inductive, datatype, primrec,
  1097 recdef) support case names and properly name parameters;
  1098 
  1099 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1100 monotonicity conditions are extracted to be proven at end of
  1101 calculations;
  1102 
  1103 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1104 method anyway;
  1105 
  1106 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1107 split_if split_if_asm; datatype package provides theorems foo.splits =
  1108 foo.split foo.split_asm for each datatype;
  1109 
  1110 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1111 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1112 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1113 use "(cases (simplified))" method in proper proof texts);
  1114 
  1115 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1116 
  1117 * Isar: names of theorems etc. may be natural numbers as well;
  1118 
  1119 * Isar: 'pr' command: optional arguments for goals_limit and
  1120 ProofContext.prems_limit; no longer prints theory contexts, but only
  1121 proof states;
  1122 
  1123 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1124 additional print modes to be specified; e.g. "pr(latex)" will print
  1125 proof state according to the Isabelle LaTeX style;
  1126 
  1127 * Isar: improved support for emulating tactic scripts, including proof
  1128 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1129 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1130 (for HOL datatypes);
  1131 
  1132 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1133 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1134 'proof method scripts' have to be in depth-first order;
  1135 
  1136 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1137 
  1138 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1139 should instead use individual commands for printing items
  1140 (print_commands, print_methods etc.);
  1141 
  1142 * Isar: added 'nothing' --- the empty list of theorems;
  1143 
  1144 
  1145 *** HOL ***
  1146 
  1147 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1148 corresponding virtual machine and a specification of its bytecode
  1149 verifier and a lightweight bytecode verifier, including proofs of
  1150 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1151 Cornelia Pusch (see also the homepage of project Bali at
  1152 http://isabelle.in.tum.de/Bali/);
  1153 
  1154 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1155 Clemens Ballarin;
  1156 
  1157 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1158 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1159 Rasmussen;
  1160 
  1161 * HOL/Lattice: fundamental concepts of lattice theory and order
  1162 structures, including duals, properties of bounds versus algebraic
  1163 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1164 Theorem for complete lattices etc.; may also serve as a demonstration
  1165 for abstract algebraic reasoning using axiomatic type classes, and
  1166 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1167 
  1168 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1169 von Oheimb;
  1170 
  1171 * HOL/IMPP: extension of IMP with local variables and mutually
  1172 recursive procedures, by David von Oheimb;
  1173 
  1174 * HOL/Lambda: converted into new-style theory and document;
  1175 
  1176 * HOL/ex/Multiquote: example of multiple nested quotations and
  1177 anti-quotations -- basically a generalized version of de-Bruijn
  1178 representation; very useful in avoiding lifting of operations;
  1179 
  1180 * HOL/record: added general record equality rule to simpset; fixed
  1181 select-update simplification procedure to handle extended records as
  1182 well; admit "r" as field name;
  1183 
  1184 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1185 other numeric types and also as the identity of groups, rings, etc.;
  1186 
  1187 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1188 Types nat and int belong to this axclass;
  1189 
  1190 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1191    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1192    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1193   two terms #m*u and #n*u are replaced by #(m+n)*u
  1194     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1195   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1196     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1197 
  1198 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1199 powerful prover for predicate logic but knows nothing of clasets; see
  1200 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1201 
  1202 * HOL: new version of "case_tac" subsumes both boolean case split and
  1203 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1204 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1205 
  1206 * HOL: simplification no longer dives into case-expressions: only the
  1207 selector expression is simplified, but not the remaining arms; to
  1208 enable full simplification of case-expressions for datatype t, you may
  1209 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1210 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1211 
  1212 * HOL/recdef: the recursion equations generated by 'recdef' for
  1213 function 'f' are now called f.simps instead of f.rules; if all
  1214 termination conditions are proved automatically, these simplification
  1215 rules are added to the simpset, as in primrec; rules may be named
  1216 individually as well, resulting in a separate list of theorems for
  1217 each equation;
  1218 
  1219 * HOL/While is a new theory that provides a while-combinator. It
  1220 permits the definition of tail-recursive functions without the
  1221 provision of a termination measure. The latter is necessary once the
  1222 invariant proof rule for while is applied.
  1223 
  1224 * HOL: new (overloaded) notation for the set of elements below/above
  1225 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1226 
  1227 * HOL: theorems impI, allI, ballI bound as "strip";
  1228 
  1229 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1230 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1231 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1232 
  1233 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1234 
  1235 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1236 main HOL, but was unused);
  1237 
  1238 * HOL: fewer consts declared as global (e.g. have to refer to
  1239 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1240 
  1241 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1242 in case of overlap with user translations (e.g. judgements over
  1243 tuples); (note that the underlying logical represenation is still
  1244 bogus);
  1245 
  1246 
  1247 *** ZF ***
  1248 
  1249 * ZF: simplification automatically cancels common terms in arithmetic
  1250 expressions over nat and int;
  1251 
  1252 * ZF: new treatment of nat to minimize type-checking: all operators
  1253 coerce their operands to a natural number using the function natify,
  1254 making the algebraic laws unconditional;
  1255 
  1256 * ZF: as above, for int: operators coerce their operands to an integer
  1257 using the function intify;
  1258 
  1259 * ZF: the integer library now contains many of the usual laws for the
  1260 orderings, including $<=, and monotonicity laws for $+ and $*;
  1261 
  1262 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1263 simplification;
  1264 
  1265 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1266 to the simplifier and classical reasoner simultaneously;
  1267 
  1268 
  1269 *** General ***
  1270 
  1271 * Provers: blast_tac now handles actual object-logic rules as
  1272 assumptions; note that auto_tac uses blast_tac internally as well;
  1273 
  1274 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1275 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1276 
  1277 * Provers: delrules now handles destruct rules as well (no longer need
  1278 explicit make_elim);
  1279 
  1280 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1281   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1282 use instead the strong form,
  1283   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1284 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1285 from destruct-rules;
  1286 
  1287 * Provers: Simplifier.easy_setup provides a fast path to basic
  1288 Simplifier setup for new object-logics;
  1289 
  1290 * Pure: AST translation rules no longer require constant head on LHS;
  1291 
  1292 * Pure: improved name spaces: ambiguous output is qualified; support
  1293 for hiding of names;
  1294 
  1295 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1296 XSYMBOL_HOME; no longer need to do manual configuration in most
  1297 situations;
  1298 
  1299 * system: compression of ML heaps images may now be controlled via -c
  1300 option of isabelle and isatool usedir (currently only observed by
  1301 Poly/ML);
  1302 
  1303 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1304 useful for remote X11);
  1305 
  1306 * system: provide TAGS file for Isabelle sources;
  1307 
  1308 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1309 order;
  1310 
  1311 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1312 timing flag supersedes proof_timing and Toplevel.trace;
  1313 
  1314 * ML: new combinators |>> and |>>> for incremental transformations
  1315 with secondary results (e.g. certain theory extensions):
  1316 
  1317 * ML: PureThy.add_defs gets additional argument to indicate potential
  1318 overloading (usually false);
  1319 
  1320 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1321 results;
  1322 
  1323 
  1324 
  1325 New in Isabelle99 (October 1999)
  1326 --------------------------------
  1327 
  1328 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1329 
  1330 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1331 are no longer simplified.  (This allows the simplifier to unfold recursive
  1332 functional programs.)  To restore the old behaviour, declare
  1333 
  1334     Delcongs [if_weak_cong];
  1335 
  1336 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1337 complement;
  1338 
  1339 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1340 
  1341 * HOL/datatype: mutual_induct_tac no longer exists --
  1342   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1343 
  1344 * HOL/typedef: fixed type inference for representing set; type
  1345 arguments now have to occur explicitly on the rhs as type constraints;
  1346 
  1347 * ZF: The con_defs part of an inductive definition may no longer refer
  1348 to constants declared in the same theory;
  1349 
  1350 * HOL, ZF: the function mk_cases, generated by the inductive
  1351 definition package, has lost an argument.  To simplify its result, it
  1352 uses the default simpset instead of a supplied list of theorems.
  1353 
  1354 * HOL/List: the constructors of type list are now Nil and Cons;
  1355 
  1356 * Simplifier: the type of the infix ML functions
  1357         setSSolver addSSolver setSolver addSolver
  1358 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1359 for packaging solvers. A solver is created via
  1360         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1361 where the string argument is only a comment.
  1362 
  1363 
  1364 *** Proof tools ***
  1365 
  1366 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1367 decision procedure for linear arithmetic. Currently it is used for
  1368 types `nat', `int', and `real' in HOL (see below); it can, should and
  1369 will be instantiated for other types and logics as well.
  1370 
  1371 * The simplifier now accepts rewrite rules with flexible heads, eg
  1372      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1373   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1374   matching.
  1375 
  1376 
  1377 *** General ***
  1378 
  1379 * New Isabelle/Isar subsystem provides an alternative to traditional
  1380 tactical theorem proving; together with the ProofGeneral/isar user
  1381 interface it offers an interactive environment for developing human
  1382 readable proof documents (Isar == Intelligible semi-automated
  1383 reasoning); for further information see isatool doc isar-ref,
  1384 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1385 
  1386 * improved and simplified presentation of theories: better HTML markup
  1387 (including colors), graph views in several sizes; isatool usedir now
  1388 provides a proper interface for user theories (via -P option); actual
  1389 document preparation based on (PDF)LaTeX is available as well (for
  1390 new-style theories only); see isatool doc system for more information;
  1391 
  1392 * native support for Proof General, both for classic Isabelle and
  1393 Isabelle/Isar;
  1394 
  1395 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1396 using the graph browser tool;
  1397 
  1398 * Isabelle manuals now also available as PDF;
  1399 
  1400 * theory loader rewritten from scratch (may not be fully
  1401 bug-compatible); old loadpath variable has been replaced by show_path,
  1402 add_path, del_path, reset_path functions; new operations such as
  1403 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1404 isatool doc ref);
  1405 
  1406 * improved isatool install: option -k creates KDE application icon,
  1407 option -p DIR installs standalone binaries;
  1408 
  1409 * added ML_PLATFORM setting (useful for cross-platform installations);
  1410 more robust handling of platform specific ML images for SML/NJ;
  1411 
  1412 * the settings environment is now statically scoped, i.e. it is never
  1413 created again in sub-processes invoked from isabelle, isatool, or
  1414 Isabelle;
  1415 
  1416 * path element specification '~~' refers to '$ISABELLE_HOME';
  1417 
  1418 * in locales, the "assumes" and "defines" parts may be omitted if
  1419 empty;
  1420 
  1421 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1422 long arrows);
  1423 
  1424 * new print_mode "HTML";
  1425 
  1426 * new flag show_tags controls display of tags of theorems (which are
  1427 basically just comments that may be attached by some tools);
  1428 
  1429 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1430 mode and goal output format:
  1431 
  1432 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1433 244c244
  1434 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1435 ---
  1436 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1437 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1438 181c181
  1439 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1440 ---
  1441 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1442 
  1443 * function bind_thms stores lists of theorems (cf. bind_thm);
  1444 
  1445 * new shorthand tactics ftac, eatac, datac, fatac;
  1446 
  1447 * qed (and friends) now accept "" as result name; in that case the
  1448 theorem is not stored, but proper checks and presentation of the
  1449 result still apply;
  1450 
  1451 * theorem database now also indexes constants "Trueprop", "all",
  1452 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1453 
  1454 
  1455 *** HOL ***
  1456 
  1457 ** HOL arithmetic **
  1458 
  1459 * There are now decision procedures for linear arithmetic over nat and
  1460 int:
  1461 
  1462 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1463 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1464 are treated as atomic; subformulae not involving type `nat' or `int'
  1465 are ignored; quantified subformulae are ignored unless they are
  1466 positive universal or negative existential. The tactic has to be
  1467 invoked by hand and can be a little bit slow. In particular, the
  1468 running time is exponential in the number of occurrences of `min' and
  1469 `max', and `-' on `nat'.
  1470 
  1471 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1472 (negated) (in)equalities among the premises and the conclusion into
  1473 account (i.e. no compound formulae) and does not know about `min' and
  1474 `max', and `-' on `nat'. It is fast and is used automatically by the
  1475 simplifier.
  1476 
  1477 NB: At the moment, these decision procedures do not cope with mixed
  1478 nat/int formulae where the two parts interact, such as `m < n ==>
  1479 int(m) < int(n)'.
  1480 
  1481 * HOL/Numeral provides a generic theory of numerals (encoded
  1482 efficiently as bit strings); setup for types nat/int/real is in place;
  1483 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1484 int, existing theories and proof scripts may require a few additional
  1485 type constraints;
  1486 
  1487 * integer division and remainder can now be performed on constant
  1488 arguments;
  1489 
  1490 * many properties of integer multiplication, division and remainder
  1491 are now available;
  1492 
  1493 * An interface to the Stanford Validity Checker (SVC) is available through the
  1494 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1495 are proved automatically.  SVC must be installed separately, and its results
  1496 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1497 invocation of the underlying oracle).  For SVC see
  1498   http://verify.stanford.edu/SVC
  1499 
  1500 * IsaMakefile: the HOL-Real target now builds an actual image;
  1501 
  1502 
  1503 ** HOL misc **
  1504 
  1505 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1506 (in Isabelle/Isar) -- by Gertrud Bauer;
  1507 
  1508 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1509 analysis for assembly languages with subtypes;
  1510 
  1511 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1512 -- avoids syntactic ambiguities and treats state, transition, and
  1513 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1514 changed syntax and (many) tactics;
  1515 
  1516 * HOL/inductive: Now also handles more general introduction rules such
  1517   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1518   theorems are now maintained within the theory (maintained via the
  1519   "mono" attribute);
  1520 
  1521 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1522   (using function types) such as
  1523 
  1524   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1525 
  1526 * HOL/record: record_simproc (part of the default simpset) takes care
  1527 of selectors applied to updated records; record_split_tac is no longer
  1528 part of the default claset; update_defs may now be removed from the
  1529 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1530 
  1531   claset_ref () := claset() addSWrapper record_split_wrapper;
  1532   Delsimprocs [record_simproc]
  1533 
  1534 * HOL/typedef: fixed type inference for representing set; type
  1535 arguments now have to occur explicitly on the rhs as type constraints;
  1536 
  1537 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1538 names rather than an ML expression;
  1539 
  1540 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1541 supplied later.  Program schemes can be defined, such as
  1542     "While B C s = (if B s then While B C (C s) else s)"
  1543 where the well-founded relation can be chosen after B and C have been given.
  1544 
  1545 * HOL/List: the constructors of type list are now Nil and Cons;
  1546 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1547 course, ML tools referring to List.list.op # etc. have to be adapted;
  1548 
  1549 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1550 disabled by default; run isabelle with option -m HOL to get back to
  1551 the original Gordon/HOL-style output;
  1552 
  1553 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1554 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1555 
  1556 * HOL basic syntax simplified (more orthogonal): all variants of
  1557 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1558 Eps operator is provided as well: "SOME x. P[x]";
  1559 
  1560 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1561 
  1562 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1563 thus available for user theories;
  1564 
  1565 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1566 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1567 time;
  1568 
  1569 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1570 several times and then mp;
  1571 
  1572 
  1573 *** LK ***
  1574 
  1575 * the notation <<...>> is now available as a notation for sequences of
  1576 formulas;
  1577 
  1578 * the simplifier is now installed
  1579 
  1580 * the axiom system has been generalized (thanks to Soren Heilmann)
  1581 
  1582 * the classical reasoner now has a default rule database
  1583 
  1584 
  1585 *** ZF ***
  1586 
  1587 * new primrec section allows primitive recursive functions to be given
  1588 directly (as in HOL) over datatypes and the natural numbers;
  1589 
  1590 * new tactics induct_tac and exhaust_tac for induction (or case
  1591 analysis) over datatypes and the natural numbers;
  1592 
  1593 * the datatype declaration of type T now defines the recursor T_rec;
  1594 
  1595 * simplification automatically does freeness reasoning for datatype
  1596 constructors;
  1597 
  1598 * automatic type-inference, with AddTCs command to insert new
  1599 type-checking rules;
  1600 
  1601 * datatype introduction rules are now added as Safe Introduction rules
  1602 to the claset;
  1603 
  1604 * the syntax "if P then x else y" is now available in addition to
  1605 if(P,x,y);
  1606 
  1607 
  1608 *** Internal programming interfaces ***
  1609 
  1610 * tuned simplifier trace output; new flag debug_simp;
  1611 
  1612 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1613 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1614 
  1615 * AxClass.axclass_tac lost the theory argument;
  1616 
  1617 * tuned current_goals_markers semantics: begin / end goal avoids
  1618 printing empty lines;
  1619 
  1620 * removed prs and prs_fn hook, which was broken because it did not
  1621 include \n in its semantics, forcing writeln to add one
  1622 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1623 string -> unit if you really want to output text without newline;
  1624 
  1625 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1626 plain output, interface builders may have to enable 'isabelle_font'
  1627 mode to get Isabelle font glyphs as before;
  1628 
  1629 * refined token_translation interface; INCOMPATIBILITY: output length
  1630 now of type real instead of int;
  1631 
  1632 * theory loader actions may be traced via new ThyInfo.add_hook
  1633 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1634 your own database of information attached to *whole* theories -- as
  1635 opposed to intra-theory data slots offered via TheoryDataFun;
  1636 
  1637 * proper handling of dangling sort hypotheses (at last!);
  1638 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1639 extra sort hypotheses that can be witnessed from the type signature;
  1640 the force_strip_shyps flag is gone, any remaining shyps are simply
  1641 left in the theorem (with a warning issued by strip_shyps_warning);
  1642 
  1643 
  1644 
  1645 New in Isabelle98-1 (October 1998)
  1646 ----------------------------------
  1647 
  1648 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1649 
  1650 * several changes of automated proof tools;
  1651 
  1652 * HOL: major changes to the inductive and datatype packages, including
  1653 some minor incompatibilities of theory syntax;
  1654 
  1655 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1656 called `inj_on';
  1657 
  1658 * HOL: removed duplicate thms in Arith:
  1659   less_imp_add_less  should be replaced by  trans_less_add1
  1660   le_imp_add_le      should be replaced by  trans_le_add1
  1661 
  1662 * HOL: unary minus is now overloaded (new type constraints may be
  1663 required);
  1664 
  1665 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1666 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1667 now taken as an integer constant.
  1668 
  1669 * Pure: ML function 'theory_of' renamed to 'theory';
  1670 
  1671 
  1672 *** Proof tools ***
  1673 
  1674 * Simplifier:
  1675   1. Asm_full_simp_tac is now more aggressive.
  1676      1. It will sometimes reorient premises if that increases their power to
  1677         simplify.
  1678      2. It does no longer proceed strictly from left to right but may also
  1679         rotate premises to achieve further simplification.
  1680      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1681      old Asm_full_simp_tac in that it does not rotate premises.
  1682   2. The simplifier now knows a little bit about nat-arithmetic.
  1683 
  1684 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1685 allows for selected deletion of wrappers, by introduction of names for
  1686 wrapper functionals.  This implies that addbefore, addSbefore,
  1687 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1688 and that adding two tactics with the same name overwrites the first
  1689 one (emitting a warning).
  1690   type wrapper = (int -> tactic) -> (int -> tactic)
  1691   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1692   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1693   delWrapper, delSWrapper: claset *  string            -> claset
  1694   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1695 
  1696 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1697 semantics; addbefore now affects only the unsafe part of step_tac
  1698 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1699 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1700 by Force_tac;
  1701 
  1702 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1703 compWrapper; added safe wrapper (and access functions for it);
  1704 
  1705 * HOL/split_all_tac is now much faster and fails if there is nothing
  1706 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1707 and the names of the automatically generated variables have changed.
  1708 split_all_tac has moved within claset() from unsafe wrappers to safe
  1709 wrappers, which means that !!-bound variables are split much more
  1710 aggressively, and safe_tac and clarify_tac now split such variables.
  1711 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1712 Note: the same holds for record_split_tac, which does the job of
  1713 split_all_tac for record fields.
  1714 
  1715 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1716 permanently to the default simpset using Addsplits just like
  1717 Addsimps. They can be removed via Delsplits just like
  1718 Delsimps. Lower-case versions are also available.
  1719 
  1720 * HOL/Simplifier: The rule split_if is now part of the default
  1721 simpset. This means that the simplifier will eliminate all occurrences
  1722 of if-then-else in the conclusion of a goal. To prevent this, you can
  1723 either remove split_if completely from the default simpset by
  1724 `Delsplits [split_if]' or remove it in a specific call of the
  1725 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1726 other case splitting rules to/from the default simpset: every datatype
  1727 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1728 t is the name of the datatype).
  1729 
  1730 * Classical reasoner / Simplifier combination: new force_tac (and
  1731 derivatives Force_tac, force) combines rewriting and classical
  1732 reasoning (and whatever other tools) similarly to auto_tac, but is
  1733 aimed to solve the given subgoal completely.
  1734 
  1735 
  1736 *** General ***
  1737 
  1738 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1739 and `goalw': the theory is no longer needed as an explicit argument -
  1740 the current theory context is used; assumptions are no longer returned
  1741 at the ML-level unless one of them starts with ==> or !!; it is
  1742 recommended to convert to these new commands using isatool fixgoal
  1743 (backup your sources first!);
  1744 
  1745 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1746 the current theory context, and 'theory' to lookup stored theories;
  1747 
  1748 * new theory section 'locale' for declaring constants, assumptions and
  1749 definitions that have local scope;
  1750 
  1751 * new theory section 'nonterminals' for purely syntactic types;
  1752 
  1753 * new theory section 'setup' for generic ML setup functions
  1754 (e.g. package initialization);
  1755 
  1756 * the distribution now includes Isabelle icons: see
  1757 lib/logo/isabelle-{small,tiny}.xpm;
  1758 
  1759 * isatool install - install binaries with absolute references to
  1760 ISABELLE_HOME/bin;
  1761 
  1762 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1763 
  1764 * print mode 'emacs' reserved for Isamode;
  1765 
  1766 * support multiple print (ast) translations per constant name;
  1767 
  1768 * theorems involving oracles are now printed with a suffixed [!];
  1769 
  1770 
  1771 *** HOL ***
  1772 
  1773 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1774 
  1775 * HOL/inductive package reorganized and improved: now supports mutual
  1776 definitions such as
  1777 
  1778   inductive EVEN ODD
  1779     intrs
  1780       null "0 : EVEN"
  1781       oddI "n : EVEN ==> Suc n : ODD"
  1782       evenI "n : ODD ==> Suc n : EVEN"
  1783 
  1784 new theorem list "elims" contains an elimination rule for each of the
  1785 recursive sets; inductive definitions now handle disjunctive premises
  1786 correctly (also ZF);
  1787 
  1788 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1789 "mutual_induct" no longer exists - the induction rule is always
  1790 contained in "induct";
  1791 
  1792 
  1793 * HOL/datatype package re-implemented and greatly improved: now
  1794 supports mutually recursive datatypes such as
  1795 
  1796   datatype
  1797     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1798             | SUM ('a aexp) ('a aexp)
  1799             | DIFF ('a aexp) ('a aexp)
  1800             | NUM 'a
  1801   and
  1802     'a bexp = LESS ('a aexp) ('a aexp)
  1803             | AND ('a bexp) ('a bexp)
  1804             | OR ('a bexp) ('a bexp)
  1805 
  1806 as well as indirectly recursive datatypes such as
  1807 
  1808   datatype
  1809     ('a, 'b) term = Var 'a
  1810                   | App 'b ((('a, 'b) term) list)
  1811 
  1812 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1813 induction on mutually / indirectly recursive datatypes.
  1814 
  1815 Primrec equations are now stored in theory and can be accessed via
  1816 <function_name>.simps.
  1817 
  1818 INCOMPATIBILITIES:
  1819 
  1820   - Theories using datatypes must now have theory Datatype as an
  1821     ancestor.
  1822   - The specific <typename>.induct_tac no longer exists - use the
  1823     generic induct_tac instead.
  1824   - natE has been renamed to nat.exhaust - use exhaust_tac
  1825     instead of res_inst_tac ... natE. Note that the variable
  1826     names in nat.exhaust differ from the names in natE, this
  1827     may cause some "fragile" proofs to fail.
  1828   - The theorems split_<typename>_case and split_<typename>_case_asm
  1829     have been renamed to <typename>.split and <typename>.split_asm.
  1830   - Since default sorts of type variables are now handled correctly,
  1831     some datatype definitions may have to be annotated with explicit
  1832     sort constraints.
  1833   - Primrec definitions no longer require function name and type
  1834     of recursive argument.
  1835 
  1836 Consider using isatool fixdatatype to adapt your theories and proof
  1837 scripts to the new package (backup your sources first!).
  1838 
  1839 
  1840 * HOL/record package: considerably improved implementation; now
  1841 includes concrete syntax for record types, terms, updates; theorems
  1842 for surjective pairing and splitting !!-bound record variables; proof
  1843 support is as follows:
  1844 
  1845   1) standard conversions (selectors or updates applied to record
  1846 constructor terms) are part of the standard simpset;
  1847 
  1848   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1849 made part of standard simpset and claset via addIffs;
  1850 
  1851   3) a tactic for record field splitting (record_split_tac) is part of
  1852 the standard claset (addSWrapper);
  1853 
  1854 To get a better idea about these rules you may retrieve them via
  1855 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1856 the name of your record type.
  1857 
  1858 The split tactic 3) conceptually simplifies by the following rule:
  1859 
  1860   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1861 
  1862 Thus any record variable that is bound by meta-all will automatically
  1863 blow up into some record constructor term, consequently the
  1864 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1865 solve record problems automatically.
  1866 
  1867 
  1868 * reorganized the main HOL image: HOL/Integ and String loaded by
  1869 default; theory Main includes everything;
  1870 
  1871 * automatic simplification of integer sums and comparisons, using cancellation;
  1872 
  1873 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1874 
  1875 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1876 
  1877 * many new identities for unions, intersections, set difference, etc.;
  1878 
  1879 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1880 called split_if, split_split, split_sum_case and split_nat_case (to go
  1881 with add/delsplits);
  1882 
  1883 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1884 (?x::unit) = (); this is made part of the default simpset, which COULD
  1885 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1886 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1887 unit_abs_eta_conv is added in order to counter the effect of
  1888 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1889 %u.f();
  1890 
  1891 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1892 makes more sense);
  1893 
  1894 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1895   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1896   disjointness reasoning but breaking a few old proofs.
  1897 
  1898 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1899 to 'converse' from 'inverse' (for compatibility with ZF and some
  1900 literature);
  1901 
  1902 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1903 the well-founded relation;
  1904 
  1905 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1906     Compl A.  The "Compl" syntax remains available as input syntax for this
  1907     release ONLY.
  1908 
  1909 * HOL/Update: new theory of function updates:
  1910     f(a:=b) == %x. if x=a then b else f x
  1911 may also be iterated as in f(a:=b,c:=d,...);
  1912 
  1913 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  1914 
  1915 * HOL/List:
  1916   - new function list_update written xs[i:=v] that updates the i-th
  1917     list position. May also be iterated as in xs[i:=a,j:=b,...].
  1918   - new function `upt' written [i..j(] which generates the list
  1919     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  1920     bound write [i..j], which is a shorthand for [i..j+1(].
  1921   - new lexicographic orderings and corresponding wellfoundedness theorems.
  1922 
  1923 * HOL/Arith:
  1924   - removed 'pred' (predecessor) function;
  1925   - generalized some theorems about n-1;
  1926   - many new laws about "div" and "mod";
  1927   - new laws about greatest common divisors (see theory ex/Primes);
  1928 
  1929 * HOL/Relation: renamed the relational operator r^-1 "converse"
  1930 instead of "inverse";
  1931 
  1932 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  1933   of the multiset ordering;
  1934 
  1935 * directory HOL/Real: a construction of the reals using Dedekind cuts
  1936   (not included by default);
  1937 
  1938 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  1939 
  1940 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  1941   programs, i.e. different program variables may have different types.
  1942 
  1943 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1944   [previously, this check worked only if the rewrite rule was unconditional]
  1945   Now rew can involve either definitions or equalities (either == or =).
  1946 
  1947 
  1948 *** ZF ***
  1949 
  1950 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  1951   only the theorems proved on ZF.ML;
  1952 
  1953 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1954   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1955   disjointness reasoning but breaking a few old proofs.
  1956 
  1957 * ZF/Update: new theory of function updates
  1958     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  1959   may also be iterated as in f(a:=b,c:=d,...);
  1960 
  1961 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  1962 
  1963 * calling (stac rew i) now fails if "rew" has no effect on the goal
  1964   [previously, this check worked only if the rewrite rule was unconditional]
  1965   Now rew can involve either definitions or equalities (either == or =).
  1966 
  1967 * case_tac provided for compatibility with HOL
  1968     (like the old excluded_middle_tac, but with subgoals swapped)
  1969 
  1970 
  1971 *** Internal programming interfaces ***
  1972 
  1973 * Pure: several new basic modules made available for general use, see
  1974 also src/Pure/README;
  1975 
  1976 * improved the theory data mechanism to support encapsulation (data
  1977 kind name replaced by private Object.kind, acting as authorization
  1978 key); new type-safe user interface via functor TheoryDataFun; generic
  1979 print_data function becomes basically useless;
  1980 
  1981 * removed global_names compatibility flag -- all theory declarations
  1982 are qualified by default;
  1983 
  1984 * module Pure/Syntax now offers quote / antiquote translation
  1985 functions (useful for Hoare logic etc. with implicit dependencies);
  1986 see HOL/ex/Antiquote for an example use;
  1987 
  1988 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  1989 cterm -> thm;
  1990 
  1991 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  1992 subgoal;
  1993 
  1994 * Display.print_goals function moved to Locale.print_goals;
  1995 
  1996 * standard print function for goals supports current_goals_markers
  1997 variable for marking begin of proof, end of proof, start of goal; the
  1998 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  1999 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2000 for example;
  2001 
  2002 
  2003 
  2004 New in Isabelle98 (January 1998)
  2005 --------------------------------
  2006 
  2007 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2008 
  2009 * changed lexical syntax of terms / types: dots made part of long
  2010 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2011 
  2012 * simpset (and claset) reference variable replaced by functions
  2013 simpset / simpset_ref;
  2014 
  2015 * no longer supports theory aliases (via merge) and non-trivial
  2016 implicit merge of thms' signatures;
  2017 
  2018 * most internal names of constants changed due to qualified names;
  2019 
  2020 * changed Pure/Sequence interface (see Pure/seq.ML);
  2021 
  2022 
  2023 *** General Changes ***
  2024 
  2025 * hierachically structured name spaces (for consts, types, axms, thms
  2026 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2027 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2028 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2029 long_names for fully qualified output names; NOTE: ML programs
  2030 (special tactics, packages etc.) referring to internal names may have
  2031 to be adapted to cope with fully qualified names; in case of severe
  2032 backward campatibility problems try setting 'global_names' at compile
  2033 time to have enrything declared within a flat name space; one may also
  2034 fine tune name declarations in theories via the 'global' and 'local'
  2035 section;
  2036 
  2037 * reimplemented the implicit simpset and claset using the new anytype
  2038 data filed in signatures; references simpset:simpset ref etc. are
  2039 replaced by functions simpset:unit->simpset and
  2040 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2041 to patch your ML files accordingly;
  2042 
  2043 * HTML output now includes theory graph data for display with Java
  2044 applet or isatool browser; data generated automatically via isatool
  2045 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2046 
  2047 * defs may now be conditional; improved rewrite_goals_tac to handle
  2048 conditional equations;
  2049 
  2050 * defs now admits additional type arguments, using TYPE('a) syntax;
  2051 
  2052 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2053 creates a new theory node; implicit merge of thms' signatures is
  2054 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2055 transfer:theory->thm->thm in (rare) cases;
  2056 
  2057 * improved handling of draft signatures / theories; draft thms (and
  2058 ctyps, cterms) are automatically promoted to real ones;
  2059 
  2060 * slightly changed interfaces for oracles: admit many per theory, named
  2061 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2062 
  2063 * print_goals: optional output of const types (set show_consts and
  2064 show_types);
  2065 
  2066 * improved output of warnings (###) and errors (***);
  2067 
  2068 * subgoal_tac displays a warning if the new subgoal has type variables;
  2069 
  2070 * removed old README and Makefiles;
  2071 
  2072 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2073 
  2074 * removed obsolete init_pps and init_database;
  2075 
  2076 * deleted the obsolete tactical STATE, which was declared by
  2077     fun STATE tacfun st = tacfun st st;
  2078 
  2079 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2080 (which abbreviates $HOME);
  2081 
  2082 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2083 use isatool fixseq to adapt your ML programs (this works for fully
  2084 qualified references to the Sequence structure only!);
  2085 
  2086 * use_thy no longer requires writable current directory; it always
  2087 reloads .ML *and* .thy file, if either one is out of date;
  2088 
  2089 
  2090 *** Classical Reasoner ***
  2091 
  2092 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2093 tactics that use classical reasoning to simplify a subgoal without
  2094 splitting it into several subgoals;
  2095 
  2096 * Safe_tac: like safe_tac but uses the default claset;
  2097 
  2098 
  2099 *** Simplifier ***
  2100 
  2101 * added simplification meta rules:
  2102     (asm_)(full_)simplify: simpset -> thm -> thm;
  2103 
  2104 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2105 logics (again);
  2106 
  2107 * added prems argument to simplification procedures;
  2108 
  2109 * HOL, FOL, ZF: added infix function `addsplits':
  2110   instead of `<simpset> setloop (split_tac <thms>)'
  2111   you can simply write `<simpset> addsplits <thms>'
  2112 
  2113 
  2114 *** Syntax ***
  2115 
  2116 * TYPE('a) syntax for type reflection terms;
  2117 
  2118 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2119 
  2120 * pretty printer: changed order of mixfix annotation preference (again!);
  2121 
  2122 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2123 
  2124 
  2125 *** HOL ***
  2126 
  2127 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2128   with `addloop' of the simplifier to faciliate case splitting in premises.
  2129 
  2130 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2131 
  2132 * HOL/Auth: new protocol proofs including some for the Internet
  2133   protocol TLS;
  2134 
  2135 * HOL/Map: new theory of `maps' a la VDM;
  2136 
  2137 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2138 cancelling out common nat summands from =, <, <= (in)equalities, or
  2139 differences; simplification procedures nat_cancel_factor for
  2140 cancelling common factor from =, <, <= (in)equalities over natural
  2141 sums; nat_cancel contains both kinds of procedures, it is installed by
  2142 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2143 
  2144 * HOL/simplifier: terms of the form
  2145   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2146   are rewritten to
  2147   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2148   and those of the form
  2149   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2150   are rewritten to
  2151   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2152 
  2153 * HOL/datatype
  2154   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2155 
  2156   P(t_case f1 ... fn x) =
  2157      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2158         ...
  2159        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2160      )
  2161 
  2162   and a theorem `split_t_case_asm' of the form
  2163 
  2164   P(t_case f1 ... fn x) =
  2165     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2166         ...
  2167        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2168      )
  2169   which can be added to a simpset via `addsplits'. The existing theorems
  2170   expand_list_case and expand_option_case have been renamed to
  2171   split_list_case and split_option_case.
  2172 
  2173 * HOL/Arithmetic:
  2174   - `pred n' is automatically converted to `n-1'.
  2175     Users are strongly encouraged not to use `pred' any longer,
  2176     because it will disappear altogether at some point.
  2177   - Users are strongly encouraged to write "0 < n" rather than
  2178     "n ~= 0". Theorems and proof tools have been modified towards this
  2179     `standard'.
  2180 
  2181 * HOL/Lists:
  2182   the function "set_of_list" has been renamed "set" (and its theorems too);
  2183   the function "nth" now takes its arguments in the reverse order and
  2184   has acquired the infix notation "!" as in "xs!n".
  2185 
  2186 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2187 
  2188 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2189   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2190 
  2191 * HOL/record: extensible records with schematic structural subtyping
  2192 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2193 still lacks various theorems and concrete record syntax;
  2194 
  2195 
  2196 *** HOLCF ***
  2197 
  2198 * removed "axioms" and "generated by" sections;
  2199 
  2200 * replaced "ops" section by extended "consts" section, which is capable of
  2201   handling the continuous function space "->" directly;
  2202 
  2203 * domain package:
  2204   . proves theorems immediately and stores them in the theory,
  2205   . creates hierachical name space,
  2206   . now uses normal mixfix annotations (instead of cinfix...),
  2207   . minor changes to some names and values (for consistency),
  2208   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2209   . separator between mutual domain defs: changed "," to "and",
  2210   . improved handling of sort constraints;  now they have to
  2211     appear on the left-hand side of the equations only;
  2212 
  2213 * fixed LAM <x,y,zs>.b syntax;
  2214 
  2215 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2216 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2217 
  2218 
  2219 *** FOL and ZF ***
  2220 
  2221 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2222   with `addloop' of the simplifier to faciliate case splitting in premises.
  2223 
  2224 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2225 in HOL, they strip ALL and --> from proved theorems;
  2226 
  2227 
  2228 
  2229 New in Isabelle94-8 (May 1997)
  2230 ------------------------------
  2231 
  2232 *** General Changes ***
  2233 
  2234 * new utilities to build / run / maintain Isabelle etc. (in parts
  2235 still somewhat experimental); old Makefiles etc. still functional;
  2236 
  2237 * new 'Isabelle System Manual';
  2238 
  2239 * INSTALL text, together with ./configure and ./build scripts;
  2240 
  2241 * reimplemented type inference for greater efficiency, better error
  2242 messages and clean internal interface;
  2243 
  2244 * prlim command for dealing with lots of subgoals (an easier way of
  2245 setting goals_limit);
  2246 
  2247 
  2248 *** Syntax ***
  2249 
  2250 * supports alternative (named) syntax tables (parser and pretty
  2251 printer); internal interface is provided by add_modesyntax(_i);
  2252 
  2253 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2254 be used in conjunction with the Isabelle symbol font; uses the
  2255 "symbols" syntax table;
  2256 
  2257 * added token_translation interface (may translate name tokens in
  2258 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2259 the current print_mode); IMPORTANT: user print translation functions
  2260 are responsible for marking newly introduced bounds
  2261 (Syntax.mark_boundT);
  2262 
  2263 * token translations for modes "xterm" and "xterm_color" that display
  2264 names in bold, underline etc. or colors (which requires a color
  2265 version of xterm);
  2266 
  2267 * infixes may now be declared with names independent of their syntax;
  2268 
  2269 * added typed_print_translation (like print_translation, but may
  2270 access type of constant);
  2271 
  2272 
  2273 *** Classical Reasoner ***
  2274 
  2275 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2276 some limitations.  Blast_tac...
  2277   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2278   + ignores elimination rules that don't have the correct format
  2279         (the conclusion MUST be a formula variable)
  2280   + ignores types, which can make HOL proofs fail
  2281   + rules must not require higher-order unification, e.g. apply_type in ZF
  2282     [message "Function Var's argument not a bound variable" relates to this]
  2283   + its proof strategy is more general but can actually be slower
  2284 
  2285 * substitution with equality assumptions no longer permutes other
  2286 assumptions;
  2287 
  2288 * minor changes in semantics of addafter (now called addaltern); renamed
  2289 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2290 (and access functions for it);
  2291 
  2292 * improved combination of classical reasoner and simplifier:
  2293   + functions for handling clasimpsets
  2294   + improvement of addss: now the simplifier is called _after_ the
  2295     safe steps.
  2296   + safe variant of addss called addSss: uses safe simplifications
  2297     _during_ the safe steps. It is more complete as it allows multiple
  2298     instantiations of unknowns (e.g. with slow_tac).
  2299 
  2300 *** Simplifier ***
  2301 
  2302 * added interface for simplification procedures (functions that
  2303 produce *proven* rewrite rules on the fly, depending on current
  2304 redex);
  2305 
  2306 * ordering on terms as parameter (used for ordered rewriting);
  2307 
  2308 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2309 
  2310 * the solver is now split into a safe and an unsafe part.
  2311 This should be invisible for the normal user, except that the
  2312 functions setsolver and addsolver have been renamed to setSolver and
  2313 addSolver; added safe_asm_full_simp_tac;
  2314 
  2315 
  2316 *** HOL ***
  2317 
  2318 * a generic induction tactic `induct_tac' which works for all datatypes and
  2319 also for type `nat';
  2320 
  2321 * a generic case distinction tactic `exhaust_tac' which works for all
  2322 datatypes and also for type `nat';
  2323 
  2324 * each datatype comes with a function `size';
  2325 
  2326 * patterns in case expressions allow tuple patterns as arguments to
  2327 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2328 
  2329 * primrec now also works with type nat;
  2330 
  2331 * recdef: a new declaration form, allows general recursive functions to be
  2332 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2333 
  2334 * the constant for negation has been renamed from "not" to "Not" to
  2335 harmonize with FOL, ZF, LK, etc.;
  2336 
  2337 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2338 infinite lists;
  2339 
  2340 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2341 
  2342 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2343 problems in commutative rings, using axiomatic type classes for + and *;
  2344 
  2345 * more examples in HOL/MiniML and HOL/Auth;
  2346 
  2347 * more default rewrite rules for quantifiers, union/intersection;
  2348 
  2349 * a new constant `arbitrary == @x.False';
  2350 
  2351 * HOLCF/IOA replaces old HOL/IOA;
  2352 
  2353 * HOLCF changes: derived all rules and arities
  2354   + axiomatic type classes instead of classes
  2355   + typedef instead of faking type definitions
  2356   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2357   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2358   + eliminated the types void, one, tr
  2359   + use unit lift and bool lift (with translations) instead of one and tr
  2360   + eliminated blift from Lift3.thy (use Def instead of blift)
  2361   all eliminated rules are derived as theorems --> no visible changes ;
  2362 
  2363 
  2364 *** ZF ***
  2365 
  2366 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2367 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2368 as ZF_cs addSIs [equalityI];
  2369 
  2370 
  2371 
  2372 New in Isabelle94-7 (November 96)
  2373 ---------------------------------
  2374 
  2375 * allowing negative levels (as offsets) in prlev and choplev;
  2376 
  2377 * super-linear speedup for large simplifications;
  2378 
  2379 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2380 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2381 FAIL); can suppress it using the command Delsimps (ex_simps @
  2382 all_simps); De Morgan laws are also now included, by default;
  2383 
  2384 * improved printing of ==>  :  ~:
  2385 
  2386 * new object-logic "Sequents" adds linear logic, while replacing LK
  2387 and Modal (thanks to Sara Kalvala);
  2388 
  2389 * HOL/Auth: correctness proofs for authentication protocols;
  2390 
  2391 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2392 examples on HOL/Auth);
  2393 
  2394 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2395 the rewriter and classical reasoner simultaneously;
  2396 
  2397 * function uresult no longer returns theorems in "standard" format;
  2398 regain previous version by: val uresult = standard o uresult;
  2399 
  2400 
  2401 
  2402 New in Isabelle94-6
  2403 -------------------
  2404 
  2405 * oracles -- these establish an interface between Isabelle and trusted
  2406 external reasoners, which may deliver results as theorems;
  2407 
  2408 * proof objects (in particular record all uses of oracles);
  2409 
  2410 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2411 
  2412 * "constdefs" section in theory files;
  2413 
  2414 * "primrec" section (HOL) no longer requires names;
  2415 
  2416 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2417 
  2418 
  2419 
  2420 New in Isabelle94-5
  2421 -------------------
  2422 
  2423 * reduced space requirements;
  2424 
  2425 * automatic HTML generation from theories;
  2426 
  2427 * theory files no longer require "..." (quotes) around most types;
  2428 
  2429 * new examples, including two proofs of the Church-Rosser theorem;
  2430 
  2431 * non-curried (1994) version of HOL is no longer distributed;
  2432 
  2433 
  2434 
  2435 New in Isabelle94-4
  2436 -------------------
  2437 
  2438 * greatly reduced space requirements;
  2439 
  2440 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2441 
  2442 * searchable theorem database (see the section "Retrieving theorems" on
  2443 page 8 of the Reference Manual);
  2444 
  2445 * new examples, including Grabczewski's monumental case study of the
  2446 Axiom of Choice;
  2447 
  2448 * The previous version of HOL renamed to Old_HOL;
  2449 
  2450 * The new version of HOL (previously called CHOL) uses a curried syntax
  2451 for functions.  Application looks like f a b instead of f(a,b);
  2452 
  2453 * Mutually recursive inductive definitions finally work in HOL;
  2454 
  2455 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2456 translates to the operator "split";
  2457 
  2458 
  2459 
  2460 New in Isabelle94-3
  2461 -------------------
  2462 
  2463 * new infix operator, addss, allowing the classical reasoner to
  2464 perform simplification at each step of its search.  Example:
  2465         fast_tac (cs addss ss)
  2466 
  2467 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2468 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2469 look like (a,b) instead of <a,b>;
  2470 
  2471 * PLEASE NOTE: CHOL will eventually replace HOL!
  2472 
  2473 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2474 It translates to the operator "split".  A new theory of integers is available;
  2475 
  2476 * In ZF, integer numerals now denote two's-complement binary integers.
  2477 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2478 
  2479 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2480 of the Axiom of Choice;
  2481 
  2482 
  2483 
  2484 New in Isabelle94-2
  2485 -------------------
  2486 
  2487 * Significantly faster resolution;
  2488 
  2489 * the different sections in a .thy file can now be mixed and repeated
  2490 freely;
  2491 
  2492 * Database of theorems for FOL, HOL and ZF.  New
  2493 commands including qed, qed_goal and bind_thm store theorems in the database.
  2494 
  2495 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2496 a given theory (thms_of), or find out what theory a theorem was proved in
  2497 (theory_of_thm);
  2498 
  2499 * Bugs fixed in the inductive definition and datatype packages;
  2500 
  2501 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2502 and HOL_dup_cs obsolete;
  2503 
  2504 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2505 have been removed;
  2506 
  2507 * Simpler definition of function space in ZF;
  2508 
  2509 * new results about cardinal and ordinal arithmetic in ZF;
  2510 
  2511 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2512 types;
  2513 
  2514 
  2515 $Id$