NEWS
author schirmer
Wed Apr 14 12:19:16 2004 +0200 (2004-04-14)
changeset 14561 c53396af770e
parent 14556 c5078f6c99a9
child 14572 1408d312d3a9
permissions -rw-r--r--
* raw control symbols are of the form \<^raw:...> now.
* again allowing symbols to begin with "\\" instead of "\" for
compatibility with ML-strings of old style theory and ML-files and
isa-ProofGeneral.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
    10   Replaces linorder.ML.
    11 
    12 * Pure: Greek letters (except small lambda, \<lambda>), as well as gothic
    13   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and euler
    14   (\<a>...\<z>), are now considered normal letters, and can therefore
    15   be used anywhere where an ASCII letter (a...zA...Z) has until
    16   now. COMPATIBILITY: This obviously changes the parsing of some
    17   terms, especially where a symbol has been used as a binder, say
    18   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
    19   as an identifier.  Fix it by inserting a space around former
    20   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
    21   existing theory and ML files.
    22 
    23 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
    24 
    25 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now 
    26   allowed in identifiers. Similar to greek letters \<^isub> is now considered 
    27   a normal (but invisible) letter. For multiple letter subscripts repeat 
    28   \<^isub> like this: x\<^isub>1\<^isub>2. 
    29 
    30 * Pure: There are now sub-/superscripts that can span more than one
    31   character. Text between \<^bsub> and \<^esub> is set in subscript in
    32   PG and LaTeX, text between \<^bsup> and \<^esup> in superscript. The
    33   new control characters are not identifier parts.
    34 
    35 * Pure: Control-symbols of the form \<^raw:...> will literally print the
    36   content of ... to the latex file instead of \isacntrl... . The ... 
    37   accepts all printable characters excluding the end bracket >.
    38 
    39 * Pure: Using new Isar command "finalconsts" (or the ML functions
    40   Theory.add_finals or Theory.add_finals_i) it is now possible to
    41   declare constants "final", which prevents their being given a definition
    42   later.  It is useful for constants whose behaviour is fixed axiomatically
    43   rather than definitionally, such as the meta-logic connectives.
    44 
    45 * Pure: It is now illegal to specify Theory.ML explicitly as a dependency
    46   in the files section of the theory Theory. (This is more of a diagnostic
    47   than a restriction, as the theory loader screws up if Theory.ML is manually
    48   loaded.)
    49 
    50 * Presentation: generated HTML now uses a CSS style sheet to make layout
    51   (somewhat) independet of content. It is copied from lib/html/isabelle.css. 
    52   It can be changed to alter the colors/layout of generated pages.
    53 
    54 
    55 *** Isar ***
    56 
    57 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
    58   cut_tac, subgoal_tac and thin_tac:
    59   - Now understand static (Isar) contexts.  As a consequence, users of Isar
    60     locales are no longer forced to write Isar proof scripts.
    61     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
    62     emulations.
    63   - INCOMPATIBILITY: names of variables to be instantiated may no
    64     longer be enclosed in quotes.  Instead, precede variable name with `?'.
    65     This is consistent with the instantiation attribute "where".
    66 
    67 * Attributes "where" and "of":
    68   - Now take type variables of instantiated theorem into account when reading
    69     the instantiation string.  This fixes a bug that caused instantiated
    70     theorems to have too special types in some circumstances.
    71   - "where" permits explicit instantiations of type variables.
    72 
    73 * Calculation commands "moreover" and "also" no longer interfere with
    74   current facts ("this"), admitting arbitrary combinations with "then"
    75   and derived forms.
    76 
    77 * Locales:
    78   - Goal statements involving the context element "includes" no longer
    79     generate theorems with internal delta predicates (those ending on
    80     "_axioms") in the premise.
    81     Resolve particular premise with <locale>.intro to obtain old form.
    82   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
    83     specification and "includes" elements in goal statement.
    84   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
    85     [intro?] and [elim?] (respectively) by default.
    86   - Experimental command for instantiation of locales in proof contexts:
    87         instantiate <label>[<attrs>]: <loc>
    88     Instantiates locale <loc> and adds all its theorems to the current context
    89     taking into account their attributes.  Label and attrs are optional
    90     modifiers, like in theorem declarations.  If present, names of
    91     instantiated theorems are qualified with <label>, and the attributes
    92     <attrs> are applied after any attributes these theorems might have already.
    93       If the locale has assumptions, a chained fact of the form
    94     "<loc> t1 ... tn" is expected from which instantiations of the parameters
    95     are derived.  The command does not support old-style locales declared
    96     with "locale (open)".
    97       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
    98 
    99 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   100   (Isar) contexts.
   101 
   102 
   103 *** HOL ***
   104 
   105 * Simplifier:
   106   - Much improved handling of linear and partial orders.
   107     Reasoners for linear and partial orders are set up for type classes
   108     "linorder" and "order" respectively, and are added to the default simpset
   109     as solvers.  This means that the simplifier can build transitivity chains
   110     to solve goals from the assumptions.
   111   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   112     of blast or auto after simplification become unnecessary because the goal
   113     is solved by simplification already.
   114 
   115 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws, 
   116     all proved in axiomatic type classes for semirings, rings and fields.
   117 
   118 * Numerics:
   119   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   120     now formalized using the Ring_and_Field theory mentioned above. 
   121   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   122     than before, because now they are set up once in a generic manner.
   123   - INCOMPATIBILITY: many type-specific arithmetic laws have gone. 
   124     Look for the general versions in Ring_and_Field (and Power if they concern
   125     exponentiation).
   126 
   127 * Type "rat" of the rational numbers is now available in HOL-Complex.
   128 
   129 * Records:
   130   - Record types are now by default printed with their type abbreviation
   131     instead of the list of all field types. This can be configured via
   132     the reference "print_record_type_abbr".
   133   - Simproc "record_upd_simproc" for simplification of multiple updates added 
   134     (not enabled by default).
   135   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   136     EX x. x = sel r to True (not enabled by default).
   137   - Tactic "record_split_simp_tac" to split and simplify records added.
   138  
   139 * 'specification' command added, allowing for definition by
   140   specification.  There is also an 'ax_specification' command that
   141   introduces the new constants axiomatically.
   142 
   143 * arith(_tac) is now able to generate counterexamples for reals as well.
   144 
   145 * HOL-Algebra: new locale "ring" for non-commutative rings.
   146 
   147 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   148  defintions, thanks to Sava Krsti\'{c} and John Matthews.
   149 
   150 * Unions and Intersections:
   151   The x-symbol output syntax of UN and INT has been changed
   152   from "\<Union>x \<in> A. B" to "\<Union\<^bsub>x \<in> A\<^esub> B"
   153   i.e. the index formulae has become a subscript, like in normal math.
   154   Similarly for "\<Union>x. B", and for \<Inter> instead of \<Union>.
   155   The subscript version is also accepted as input syntax.
   156 
   157 * Unions and Intersections over Intervals:
   158   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is 
   159   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A" 
   160   like in normal math, and corresponding versions for < and for intersection.
   161 
   162 * ML: the legacy theory structures Int and List have been removed. They had
   163   conflicted with ML Basis Library structures having the same names.
   164 
   165 * 'refute' command added to search for (finite) countermodels.  Only works
   166   for a fragment of HOL.  The installation of an external SAT solver is
   167   highly recommended.  See "HOL/Refute.thy" for details.
   168 
   169 
   170 *** HOLCF ***
   171 
   172 * Streams now come with concatenation and are part of the HOLCF image
   173 
   174 New in Isabelle2003 (May 2003)
   175 --------------------------------
   176 
   177 *** General ***
   178 
   179 * Provers/simplifier:
   180 
   181   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   182     Assumptions are now subject to complete mutual simplification,
   183     not just from left to right. The simplifier now preserves
   184     the order of assumptions.
   185 
   186     Potential INCOMPATIBILITY:
   187 
   188     -- simp sometimes diverges where the old version did
   189        not, e.g. invoking simp on the goal
   190 
   191         [| P (f x); y = x; f x = f y |] ==> Q
   192 
   193        now gives rise to the infinite reduction sequence
   194 
   195         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   196 
   197        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   198        kind of problem.
   199 
   200     -- Tactics combining classical reasoner and simplification (such as auto)
   201        are also affected by this change, because many of them rely on
   202        simp. They may sometimes diverge as well or yield a different numbers
   203        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   204        in case of problems. Sometimes subsequent calls to the classical
   205        reasoner will fail because a preceeding call to the simplifier too
   206        eagerly simplified the goal, e.g. deleted redundant premises.
   207 
   208   - The simplifier trace now shows the names of the applied rewrite rules
   209 
   210   - You can limit the number of recursive invocations of the simplifier
   211     during conditional rewriting (where the simplifie tries to solve the
   212     conditions before applying the rewrite rule):
   213     ML "simp_depth_limit := n"
   214     where n is an integer. Thus you can force termination where previously
   215     the simplifier would diverge.
   216 
   217   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   218 
   219   - No longer aborts on failed congruence proof.  Instead, the
   220     congruence is ignored.
   221 
   222 * Pure: New generic framework for extracting programs from constructive
   223   proofs. See HOL/Extraction.thy for an example instantiation, as well
   224   as HOL/Extraction for some case studies.
   225 
   226 * Pure: The main goal of the proof state is no longer shown by default, only
   227 the subgoals. This behaviour is controlled by a new flag.
   228    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   229 (ML: Proof.show_main_goal).
   230 
   231 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   232 rules whose conclusion matches subgoal 1:
   233       PG menu: Isabelle/Isar -> Show me -> matching rules
   234 The rules are ordered by how closely they match the subgoal.
   235 In particular, rules that solve a subgoal outright are displayed first
   236 (or rather last, the way they are printed).
   237 (ML: ProofGeneral.print_intros())
   238 
   239 * Pure: New flag trace_unify_fail causes unification to print
   240 diagnostic information (PG: in trace buffer) when it fails. This is
   241 useful for figuring out why single step proofs like rule, erule or
   242 assumption failed.
   243 
   244 * Pure: Locale specifications now produce predicate definitions
   245 according to the body of text (covering assumptions modulo local
   246 definitions); predicate "loc_axioms" covers newly introduced text,
   247 while "loc" is cumulative wrt. all included locale expressions; the
   248 latter view is presented only on export into the global theory
   249 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   250 on the old view without predicates;
   251 
   252 * Pure: predefined locales "var" and "struct" are useful for sharing
   253 parameters (as in CASL, for example); just specify something like
   254 ``var x + var y + struct M'' as import;
   255 
   256 * Pure: improved thms_containing: proper indexing of facts instead of
   257 raw theorems; check validity of results wrt. current name space;
   258 include local facts of proof configuration (also covers active
   259 locales), cover fixed variables in index; may use "_" in term
   260 specification; an optional limit for the number of printed facts may
   261 be given (the default is 40);
   262 
   263 * Pure: disallow duplicate fact bindings within new-style theory files
   264 (batch-mode only);
   265 
   266 * Provers: improved induct method: assumptions introduced by case
   267 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   268 the goal statement); "foo" still refers to all facts collectively;
   269 
   270 * Provers: the function blast.overloaded has been removed: all constants
   271 are regarded as potentially overloaded, which improves robustness in exchange
   272 for slight decrease in efficiency;
   273 
   274 * Provers/linorder: New generic prover for transitivity reasoning over
   275 linear orders.  Note: this prover is not efficient!
   276 
   277 * Isar: preview of problems to finish 'show' now produce an error
   278 rather than just a warning (in interactive mode);
   279 
   280 
   281 *** HOL ***
   282 
   283 * arith(_tac)
   284 
   285  - Produces a counter example if it cannot prove a goal.
   286    Note that the counter example may be spurious if the goal is not a formula
   287    of quantifier-free linear arithmetic.
   288    In ProofGeneral the counter example appears in the trace buffer.
   289 
   290  - Knows about div k and mod k where k is a numeral of type nat or int.
   291 
   292  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   293    linear arithmetic fails. This takes account of quantifiers and divisibility.
   294    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   295 
   296 * simp's arithmetic capabilities have been enhanced a bit: it now
   297 takes ~= in premises into account (by performing a case split);
   298 
   299 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   300 are distributed over a sum of terms;
   301 
   302 * New tactic "trans_tac" and method "trans" instantiate
   303 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   304 "<=", "<" and "="). 
   305 
   306 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   307 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   308 
   309 * 'typedef' command has new option "open" to suppress the set
   310 definition;
   311 
   312 * functions Min and Max on finite sets have been introduced (theory
   313 Finite_Set);
   314 
   315 * attribute [symmetric] now works for relations as well; it turns
   316 (x,y) : R^-1 into (y,x) : R, and vice versa;
   317 
   318 * induct over a !!-quantified statement (say !!x1..xn):
   319   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   320 
   321 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   322 %x. None. Warning: empty_def now refers to the previously hidden definition
   323 of the empty set.
   324 
   325 * Algebra: formalization of classical algebra.  Intended as base for
   326 any algebraic development in Isabelle.  Currently covers group theory
   327 (up to Sylow's theorem) and ring theory (Universal Property of
   328 Univariate Polynomials).  Contributions welcome;
   329 
   330 * GroupTheory: deleted, since its material has been moved to Algebra;
   331 
   332 * Complex: new directory of the complex numbers with numeric constants, 
   333 nonstandard complex numbers, and some complex analysis, standard and 
   334 nonstandard (Jacques Fleuriot);
   335 
   336 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   337 
   338 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   339 Fleuriot);
   340 
   341 * Real/HahnBanach: updated and adapted to locales;
   342 
   343 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   344 Gray and Kramer);
   345 
   346 * UNITY: added the Meier-Sanders theory of progress sets;
   347 
   348 * MicroJava: bytecode verifier and lightweight bytecode verifier
   349 as abstract algorithms, instantiated to the JVM;
   350 
   351 * Bali: Java source language formalization. Type system, operational
   352 semantics, axiomatic semantics. Supported language features:
   353 classes, interfaces, objects,virtual methods, static methods,
   354 static/instance fields, arrays, access modifiers, definite
   355 assignment, exceptions.
   356 
   357 
   358 *** ZF ***
   359 
   360 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   361 universe, etc.);
   362 
   363 * Main ZF: virtually all theories converted to new-style format;
   364 
   365 
   366 *** ML ***
   367 
   368 * Pure: Tactic.prove provides sane interface for internal proofs;
   369 omits the infamous "standard" operation, so this is more appropriate
   370 than prove_goalw_cterm in many situations (e.g. in simprocs);
   371 
   372 * Pure: improved error reporting of simprocs;
   373 
   374 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   375 up simprocs;
   376 
   377 
   378 *** Document preparation ***
   379 
   380 * uses \par instead of \\ for line breaks in theory text. This may
   381 shift some page breaks in large documents. To get the old behaviour
   382 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   383 
   384 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   385 other packages
   386 
   387 * \<euro> now needs package babel/greek instead of marvosym (which
   388 broke \Rightarrow)
   389 
   390 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   391 textcomp package)
   392 
   393 
   394 New in Isabelle2002 (March 2002)
   395 --------------------------------
   396 
   397 *** Document preparation ***
   398 
   399 * greatly simplified document preparation setup, including more
   400 graceful interpretation of isatool usedir -i/-d/-D options, and more
   401 instructive isatool mkdir; users should basically be able to get
   402 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   403 users may run a separate document processing stage manually like this:
   404 "isatool usedir -D output HOL Test && isatool document Test/output";
   405 
   406 * theory dependency graph may now be incorporated into documents;
   407 isatool usedir -g true will produce session_graph.eps/.pdf for use
   408 with \includegraphics of LaTeX;
   409 
   410 * proper spacing of consecutive markup elements, especially text
   411 blocks after section headings;
   412 
   413 * support bold style (for single symbols only), input syntax is like
   414 this: "\<^bold>\<alpha>" or "\<^bold>A";
   415 
   416 * \<bullet> is now output as bold \cdot by default, which looks much
   417 better in printed text;
   418 
   419 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   420 note that these symbols are currently unavailable in Proof General /
   421 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   422 
   423 * isatool latex no longer depends on changed TEXINPUTS, instead
   424 isatool document copies the Isabelle style files to the target
   425 location;
   426 
   427 
   428 *** Isar ***
   429 
   430 * Pure/Provers: improved proof by cases and induction;
   431   - 'case' command admits impromptu naming of parameters (such as
   432     "case (Suc n)");
   433   - 'induct' method divinates rule instantiation from the inductive
   434     claim; no longer requires excessive ?P bindings for proper
   435     instantiation of cases;
   436   - 'induct' method properly enumerates all possibilities of set/type
   437     rules; as a consequence facts may be also passed through *type*
   438     rules without further ado;
   439   - 'induct' method now derives symbolic cases from the *rulified*
   440     rule (before it used to rulify cases stemming from the internal
   441     atomized version); this means that the context of a non-atomic
   442     statement becomes is included in the hypothesis, avoiding the
   443     slightly cumbersome show "PROP ?case" form;
   444   - 'induct' may now use elim-style induction rules without chaining
   445     facts, using ``missing'' premises from the goal state; this allows
   446     rules stemming from inductive sets to be applied in unstructured
   447     scripts, while still benefitting from proper handling of non-atomic
   448     statements; NB: major inductive premises need to be put first, all
   449     the rest of the goal is passed through the induction;
   450   - 'induct' proper support for mutual induction involving non-atomic
   451     rule statements (uses the new concept of simultaneous goals, see
   452     below);
   453   - append all possible rule selections, but only use the first
   454     success (no backtracking);
   455   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   456   - undeclared rule case names default to numbers 1, 2, 3, ...;
   457   - added 'print_induct_rules' (covered by help item in recent Proof
   458     General versions);
   459   - moved induct/cases attributes to Pure, methods to Provers;
   460   - generic method setup instantiated for FOL and HOL;
   461 
   462 * Pure: support multiple simultaneous goal statements, for example
   463 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   464 meta-level mechanism, this acts as if several individual goals had
   465 been stated separately; in particular common proof methods need to be
   466 repeated in order to cover all claims; note that a single elimination
   467 step is *not* sufficient to establish the two conjunctions, so this
   468 fails:
   469 
   470   assume "A & B" then have A and B ..   (*".." fails*)
   471 
   472 better use "obtain" in situations as above; alternative refer to
   473 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   474 
   475 * Pure: proper integration with ``locales''; unlike the original
   476 version by Florian Kammüller, Isar locales package high-level proof
   477 contexts rather than raw logical ones (e.g. we admit to include
   478 attributes everywhere); operations on locales include merge and
   479 rename; support for implicit arguments (``structures''); simultaneous
   480 type-inference over imports and text; see also HOL/ex/Locales.thy for
   481 some examples;
   482 
   483 * Pure: the following commands have been ``localized'', supporting a
   484 target locale specification "(in name)": 'lemma', 'theorem',
   485 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   486 stored both within the locale and at the theory level (exported and
   487 qualified by the locale name);
   488 
   489 * Pure: theory goals may now be specified in ``long'' form, with
   490 ad-hoc contexts consisting of arbitrary locale elements. for example
   491 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   492 definitions may be given, too); the result is a meta-level rule with
   493 the context elements being discharged in the obvious way;
   494 
   495 * Pure: new proof command 'using' allows to augment currently used
   496 facts after a goal statement ('using' is syntactically analogous to
   497 'apply', but acts on the goal's facts only); this allows chained facts
   498 to be separated into parts given before and after a claim, as in
   499 ``from a and b have C using d and e <proof>'';
   500 
   501 * Pure: renamed "antecedent" case to "rule_context";
   502 
   503 * Pure: new 'judgment' command records explicit information about the
   504 object-logic embedding (used by several tools internally); no longer
   505 use hard-wired "Trueprop";
   506 
   507 * Pure: added 'corollary' command;
   508 
   509 * Pure: fixed 'token_translation' command;
   510 
   511 * Pure: removed obsolete 'exported' attribute;
   512 
   513 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   514 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   515 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   516 
   517 * Pure: method 'atomize' presents local goal premises as object-level
   518 statements (atomic meta-level propositions); setup controlled via
   519 rewrite rules declarations of 'atomize' attribute; example
   520 application: 'induct' method with proper rule statements in improper
   521 proof *scripts*;
   522 
   523 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   524 now consider the syntactic context of assumptions, giving a better
   525 chance to get type-inference of the arguments right (this is
   526 especially important for locales);
   527 
   528 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   529 mode;
   530 
   531 * Pure/obtain: the formal conclusion "thesis", being marked as
   532 ``internal'', may no longer be reference directly in the text;
   533 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   534 situations;
   535 
   536 * Pure: generic 'sym' attribute which declares a rule both as pure
   537 'elim?' and for the 'symmetric' operation;
   538 
   539 * Pure: marginal comments ``--'' may now occur just anywhere in the
   540 text; the fixed correlation with particular command syntax has been
   541 discontinued;
   542 
   543 * Pure: new method 'rules' is particularly well-suited for proof
   544 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   545 but often produces more compact proof terms with less detours;
   546 
   547 * Pure/Provers/classical: simplified integration with pure rule
   548 attributes and methods; the classical "intro?/elim?/dest?"
   549 declarations coincide with the pure ones; the "rule" method no longer
   550 includes classically swapped intros; "intro" and "elim" methods no
   551 longer pick rules from the context; also got rid of ML declarations
   552 AddXIs/AddXEs/AddXDs; all of this has some potential for
   553 INCOMPATIBILITY;
   554 
   555 * Provers/classical: attribute 'swapped' produces classical inversions
   556 of introduction rules;
   557 
   558 * Provers/simplifier: 'simplified' attribute may refer to explicit
   559 rules instead of full simplifier context; 'iff' attribute handles
   560 conditional rules;
   561 
   562 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   563 
   564 * HOL: 'recdef' now fails on unfinished automated proofs, use
   565 "(permissive)" option to recover old behavior;
   566 
   567 * HOL: 'inductive' no longer features separate (collective) attributes
   568 for 'intros' (was found too confusing);
   569 
   570 * HOL: properly declared induction rules less_induct and
   571 wf_induct_rule;
   572 
   573 
   574 *** HOL ***
   575 
   576 * HOL: moved over to sane numeral syntax; the new policy is as
   577 follows:
   578 
   579   - 0 and 1 are polymorphic constants, which are defined on any
   580   numeric type (nat, int, real etc.);
   581 
   582   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   583   binary representation internally;
   584 
   585   - type nat has special constructor Suc, and generally prefers Suc 0
   586   over 1::nat and Suc (Suc 0) over 2::nat;
   587 
   588 This change may cause significant problems of INCOMPATIBILITY; here
   589 are some hints on converting existing sources:
   590 
   591   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   592   entities, so expressions involving "-" (unary or binary minus) need
   593   to be spaced properly;
   594 
   595   - existing occurrences of "1" may need to be constraint "1::nat" or
   596   even replaced by Suc 0; similar for old "2";
   597 
   598   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   599 
   600   - remove all special provisions on numerals in proofs;
   601 
   602 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   603 representation (depends on bin_arith_simps in the default context);
   604 
   605 * HOL: symbolic syntax for x^2 (numeral 2);
   606 
   607 * HOL: the class of all HOL types is now called "type" rather than
   608 "term"; INCOMPATIBILITY, need to adapt references to this type class
   609 in axclass/classes, instance/arities, and (usually rare) occurrences
   610 in typings (of consts etc.); internally the class is called
   611 "HOL.type", ML programs should refer to HOLogic.typeS;
   612 
   613 * HOL/record package improvements:
   614   - new derived operations "fields" to build a partial record section,
   615     "extend" to promote a fixed record to a record scheme, and
   616     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   617     declared as simp by default;
   618   - shared operations ("more", "fields", etc.) now need to be always
   619     qualified) --- potential INCOMPATIBILITY;
   620   - removed "make_scheme" operations (use "make" with "extend") --
   621     INCOMPATIBILITY;
   622   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   623   - provides cases/induct rules for use with corresponding Isar
   624     methods (for concrete records, record schemes, concrete more
   625     parts, and schematic more parts -- in that order);
   626   - internal definitions directly based on a light-weight abstract
   627     theory of product types over typedef rather than datatype;
   628 
   629 * HOL: generic code generator for generating executable ML code from
   630 specifications; specific support for HOL constructs such as inductive
   631 datatypes and sets, as well as recursive functions; can be invoked
   632 via 'generate_code' theory section;
   633 
   634 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   635 
   636 * HOL: consolidated and renamed several theories.  In particular:
   637 	Ord.thy has been absorbed into HOL.thy
   638 	String.thy has been absorbed into List.thy
   639  
   640 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   641 (beware of argument permutation!);
   642 
   643 * HOL: linorder_less_split superseded by linorder_cases;
   644 
   645 * HOL/List: "nodups" renamed to "distinct";
   646 
   647 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   648 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   649   - Ex_def has changed, now need to use some_eq_ex
   650 
   651 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   652 in this (rare) case use:
   653 
   654   delSWrapper "split_all_tac"
   655   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   656 
   657 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   658 MAY FAIL;
   659 
   660 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   661 Isabelle's type classes, ^ on functions and relations has too general
   662 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   663 necessary to attach explicit type constraints;
   664 
   665 * HOL/Relation: the prefix name of the infix "O" has been changed from
   666 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   667 renamed accordingly (eg "compI" -> "rel_compI").
   668 
   669 * HOL: syntax translations now work properly with numerals and records
   670 expressions;
   671 
   672 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   673 of "lam" -- INCOMPATIBILITY;
   674 
   675 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   676 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   677 renamed "Product_Type.unit";
   678 
   679 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   680 
   681 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   682 the "cases" method);
   683 
   684 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   685 Florian Kammüller);
   686 
   687 * HOL/IMP: updated and converted to new-style theory format; several
   688 parts turned into readable document, with proper Isar proof texts and
   689 some explanations (by Gerwin Klein);
   690 
   691 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   692 
   693 * HOL-Hyperreal is now a logic image;
   694 
   695 
   696 *** HOLCF ***
   697 
   698 * Isar: consts/constdefs supports mixfix syntax for continuous
   699 operations;
   700 
   701 * Isar: domain package adapted to new-style theory format, e.g. see
   702 HOLCF/ex/Dnat.thy;
   703 
   704 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   705 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   706 lift.induct_tac, always use UU instead of Undef;
   707 
   708 * HOLCF/IMP: updated and converted to new-style theory;
   709 
   710 
   711 *** ZF ***
   712 
   713 * Isar: proper integration of logic-specific tools and packages,
   714 including theory commands '(co)inductive', '(co)datatype',
   715 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   716 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   717 
   718 * theory Main no longer includes AC; for the Axiom of Choice, base
   719 your theory on Main_ZFC;
   720 
   721 * the integer library now covers quotients and remainders, with many
   722 laws relating division to addition, multiplication, etc.;
   723 
   724 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   725 typeless version of the formalism;
   726 
   727 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   728 format;
   729 
   730 * ZF/Induct: new directory for examples of inductive definitions,
   731 including theory Multiset for multiset orderings; converted to
   732 new-style theory format;
   733 
   734 * ZF: many new theorems about lists, ordinals, etc.;
   735 
   736 
   737 *** General ***
   738 
   739 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   740 variable proof controls level of detail: 0 = no proofs (only oracle
   741 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   742 also ref manual for further ML interfaces;
   743 
   744 * Pure/axclass: removed obsolete ML interface
   745 goal_subclass/goal_arity;
   746 
   747 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   748 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   749 separate tokens, so expressions involving minus need to be spaced
   750 properly;
   751 
   752 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   753 rather than "infixl" or "infixr";
   754 
   755 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   756 sort constraint specifications in type inference; e.g. "x::_::foo"
   757 ensures that the type of "x" is of sort "foo" (but not necessarily a
   758 type variable);
   759 
   760 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   761 control output of nested => (types); the default behavior is
   762 "type_brackets";
   763 
   764 * Pure/syntax: builtin parse translation for "_constify" turns valued
   765 tokens into AST constants;
   766 
   767 * Pure/syntax: prefer later declarations of translations and print
   768 translation functions; potential INCOMPATIBILITY: need to reverse
   769 multiple declarations for same syntax element constant;
   770 
   771 * Pure/show_hyps reset by default (in accordance to existing Isar
   772 practice);
   773 
   774 * Provers/classical: renamed addaltern to addafter, addSaltern to
   775 addSafter;
   776 
   777 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   778 as well;
   779 
   780 * system: tested support for MacOS X; should be able to get Isabelle +
   781 Proof General to work in a plain Terminal after installing Poly/ML
   782 (e.g. from the Isabelle distribution area) and GNU bash alone
   783 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   784 support requires further installations, e.g. from
   785 http://fink.sourceforge.net/);
   786 
   787 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   788 
   789 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   790 of 40 MB), cf. ML_OPTIONS;
   791 
   792 * system: Proof General keywords specification is now part of the
   793 Isabelle distribution (see etc/isar-keywords.el);
   794 
   795 * system: support for persistent Proof General sessions (refrain from
   796 outdating all loaded theories on startup); user may create writable
   797 logic images like this: ``isabelle -q HOL Test'';
   798 
   799 * system: smart selection of Isabelle process versus Isabelle
   800 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   801 run both "isabelle" and "Isabelle" even if file names are badly
   802 damaged (executable inspects the case of the first letter of its own
   803 name); added separate "isabelle-process" and "isabelle-interface";
   804 
   805 * system: refrain from any attempt at filtering input streams; no
   806 longer support ``8bit'' encoding of old isabelle font, instead proper
   807 iso-latin characters may now be used; the related isatools
   808 "symbolinput" and "nonascii" have disappeared as well;
   809 
   810 * system: removed old "xterm" interface (the print modes "xterm" and
   811 "xterm_color" are still available for direct use in a suitable
   812 terminal);
   813 
   814 
   815 
   816 New in Isabelle99-2 (February 2001)
   817 -----------------------------------
   818 
   819 *** Overview of INCOMPATIBILITIES ***
   820 
   821 * HOL: please note that theories in the Library and elsewhere often use the
   822 new-style (Isar) format; to refer to their theorems in an ML script you must
   823 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   824 
   825 * HOL: inductive package no longer splits induction rule aggressively,
   826 but only as far as specified by the introductions given; the old
   827 format may be recovered via ML function complete_split_rule or attribute
   828 'split_rule (complete)';
   829 
   830 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   831 gfp_Tarski to gfp_unfold;
   832 
   833 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   834 
   835 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   836 relation); infix "^^" has been renamed "``"; infix "``" has been
   837 renamed "`"; "univalent" has been renamed "single_valued";
   838 
   839 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   840 operation;
   841 
   842 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   843 
   844 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   845 
   846 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   847 consequence, it is no longer monotonic wrt. the local goal context
   848 (which is now passed through the inductive cases);
   849 
   850 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   851 \<gg> to \<ggreater>;
   852 
   853 
   854 *** Document preparation ***
   855 
   856 * \isabellestyle{NAME} selects version of Isabelle output (currently
   857 available: are "it" for near math-mode best-style output, "sl" for
   858 slanted text style, and "tt" for plain type-writer; if no
   859 \isabellestyle command is given, output is according to slanted
   860 type-writer);
   861 
   862 * support sub/super scripts (for single symbols only), input syntax is
   863 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   864 
   865 * some more standard symbols; see Appendix A of the system manual for
   866 the complete list of symbols defined in isabellesym.sty;
   867 
   868 * improved isabelle style files; more abstract symbol implementation
   869 (should now use \isamath{...} and \isatext{...} in custom symbol
   870 definitions);
   871 
   872 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   873 state; Note that presentation of goal states does not conform to
   874 actual human-readable proof documents.  Please do not include goal
   875 states into document output unless you really know what you are doing!
   876 
   877 * proper indentation of antiquoted output with proportional LaTeX
   878 fonts;
   879 
   880 * no_document ML operator temporarily disables LaTeX document
   881 generation;
   882 
   883 * isatool unsymbolize tunes sources for plain ASCII communication;
   884 
   885 
   886 *** Isar ***
   887 
   888 * Pure: Isar now suffers initial goal statements to contain unbound
   889 schematic variables (this does not conform to actual readable proof
   890 documents, due to unpredictable outcome and non-compositional proof
   891 checking); users who know what they are doing may use schematic goals
   892 for Prolog-style synthesis of proven results;
   893 
   894 * Pure: assumption method (an implicit finishing) now handles actual
   895 rules as well;
   896 
   897 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   898 initial goal, declare "that" only as Pure intro (only for single
   899 steps); the "that" rule assumption may now be involved in implicit
   900 finishing, thus ".." becomes a feasible for trivial obtains;
   901 
   902 * Pure: default proof step now includes 'intro_classes'; thus trivial
   903 instance proofs may be performed by "..";
   904 
   905 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   906 statements as well;
   907 
   908 * Pure: more robust selection of calculational rules;
   909 
   910 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   911 rule (as well as the assumption rule);
   912 
   913 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   914 lemmas, using the graph browser tool;
   915 
   916 * Pure: predict failure of "show" in interactive mode;
   917 
   918 * Pure: 'thms_containing' now takes actual terms as arguments;
   919 
   920 * HOL: improved method 'induct' --- now handles non-atomic goals
   921 (potential INCOMPATIBILITY); tuned error handling;
   922 
   923 * HOL: cases and induct rules now provide explicit hints about the
   924 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   925 any remaining facts are inserted into the goal verbatim;
   926 
   927 * HOL: local contexts (aka cases) may now contain term bindings as
   928 well; the 'cases' and 'induct' methods new provide a ?case binding for
   929 the result to be shown in each case;
   930 
   931 * HOL: added 'recdef_tc' command;
   932 
   933 * isatool convert assists in eliminating legacy ML scripts;
   934 
   935 
   936 *** HOL ***
   937 
   938 * HOL/Library: a collection of generic theories to be used together
   939 with main HOL; the theory loader path already includes this directory
   940 by default; the following existing theories have been moved here:
   941 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   942 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   943 
   944 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   945 modelling and verification task performed in Isabelle/HOL +
   946 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   947 
   948 * HOL/Algebra: special summation operator SUM no longer exists, it has
   949 been replaced by setsum; infix 'assoc' now has priority 50 (like
   950 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   951 'domain', this makes the theory consistent with mathematical
   952 literature;
   953 
   954 * HOL basics: added overloaded operations "inverse" and "divide"
   955 (infix "/"), syntax for generic "abs" operation, generic summation
   956 operator \<Sum>;
   957 
   958 * HOL/typedef: simplified package, provide more useful rules (see also
   959 HOL/subset.thy);
   960 
   961 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   962 now expressed as a proper nested rule (old-style tactic scripts may
   963 require atomize_strip_tac to cope with non-atomic premises);
   964 
   965 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   966 to "split_conv" (old name still available for compatibility);
   967 
   968 * HOL: improved concrete syntax for strings (e.g. allows translation
   969 rules with string literals);
   970 
   971 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   972  and Fleuriot's mechanization of analysis, including the transcendental
   973  functions for the reals;
   974 
   975 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   976 
   977 
   978 *** CTT ***
   979 
   980 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   981 "lam" is displayed as TWO lambda-symbols
   982 
   983 * CTT: theory Main now available, containing everything (that is, Bool
   984 and Arith);
   985 
   986 
   987 *** General ***
   988 
   989 * Pure: the Simplifier has been implemented properly as a derived rule
   990 outside of the actual kernel (at last!); the overall performance
   991 penalty in practical applications is about 50%, while reliability of
   992 the Isabelle inference kernel has been greatly improved;
   993 
   994 * print modes "brackets" and "no_brackets" control output of nested =>
   995 (types) and ==> (props); the default behaviour is "brackets";
   996 
   997 * Provers: fast_tac (and friends) now handle actual object-logic rules
   998 as assumptions as well;
   999 
  1000 * system: support Poly/ML 4.0;
  1001 
  1002 * system: isatool install handles KDE version 1 or 2;
  1003 
  1004 
  1005 
  1006 New in Isabelle99-1 (October 2000)
  1007 ----------------------------------
  1008 
  1009 *** Overview of INCOMPATIBILITIES ***
  1010 
  1011 * HOL: simplification of natural numbers is much changed; to partly
  1012 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1013 issue the following ML commands:
  1014 
  1015   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1016   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1017 
  1018 * HOL: simplification no longer dives into case-expressions; this is
  1019 controlled by "t.weak_case_cong" for each datatype t;
  1020 
  1021 * HOL: nat_less_induct renamed to less_induct;
  1022 
  1023 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1024 fixsome to patch .thy and .ML sources automatically;
  1025 
  1026   select_equality  -> some_equality
  1027   select_eq_Ex     -> some_eq_ex
  1028   selectI2EX       -> someI2_ex
  1029   selectI2         -> someI2
  1030   selectI          -> someI
  1031   select1_equality -> some1_equality
  1032   Eps_sym_eq       -> some_sym_eq_trivial
  1033   Eps_eq           -> some_eq_trivial
  1034 
  1035 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1036 
  1037 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1038 instead);
  1039 
  1040 * HOL: the recursion equations generated by 'recdef' are now called
  1041 f.simps instead of f.rules;
  1042 
  1043 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1044 
  1045 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1046 sometimes be needed;
  1047 
  1048 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1049 
  1050 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1051 
  1052 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1053 product is now "<*>" instead of "Times"; the lexicographic product is
  1054 now "<*lex*>" instead of "**";
  1055 
  1056 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1057 of main HOL, but was unused); better use HOL's datatype package;
  1058 
  1059 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1060 the old syntax may be recovered as follows:
  1061 
  1062   syntax (symbols)
  1063     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1064       (infixl "\\<oplus>" 100)
  1065 
  1066 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1067 
  1068 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1069 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1070 internally;
  1071 
  1072 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1073 changed from A/r to A//r;
  1074 
  1075 * ZF: new treatment of arithmetic (nat & int) may break some old
  1076 proofs;
  1077 
  1078 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1079 rulify -> rule_format, elimify -> elim_format, ...);
  1080 
  1081 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1082 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1083 should have to change intro!! to intro? only); replaced "delrule" by
  1084 "rule del";
  1085 
  1086 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1087 
  1088 * Provers: strengthened force_tac by using new first_best_tac;
  1089 
  1090 * LaTeX document preparation: several changes of isabelle.sty (see
  1091 lib/texinputs);
  1092 
  1093 
  1094 *** Document preparation ***
  1095 
  1096 * formal comments (text blocks etc.) in new-style theories may now
  1097 contain antiquotations of thm/prop/term/typ/text to be presented
  1098 according to latex print mode; concrete syntax is like this:
  1099 @{term[show_types] "f(x) = a + x"};
  1100 
  1101 * isatool mkdir provides easy setup of Isabelle session directories,
  1102 including proper document sources;
  1103 
  1104 * generated LaTeX sources are now deleted after successful run
  1105 (isatool document -c); may retain a copy somewhere else via -D option
  1106 of isatool usedir;
  1107 
  1108 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1109 style files, achieving self-contained LaTeX sources and simplifying
  1110 LaTeX debugging;
  1111 
  1112 * old-style theories now produce (crude) LaTeX output as well;
  1113 
  1114 * browser info session directories are now self-contained (may be put
  1115 on WWW server seperately); improved graphs of nested sessions; removed
  1116 graph for 'all sessions';
  1117 
  1118 * several improvements in isabelle style files; \isabellestyle{it}
  1119 produces fake math mode output; \isamarkupheader is now \section by
  1120 default; see lib/texinputs/isabelle.sty etc.;
  1121 
  1122 
  1123 *** Isar ***
  1124 
  1125 * Isar/Pure: local results and corresponding term bindings are now
  1126 subject to Hindley-Milner polymorphism (similar to ML); this
  1127 accommodates incremental type-inference very nicely;
  1128 
  1129 * Isar/Pure: new derived language element 'obtain' supports
  1130 generalized existence reasoning;
  1131 
  1132 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1133 support accumulation of results, without applying any rules yet;
  1134 useful to collect intermediate results without explicit name
  1135 references, and for use with transitivity rules with more than 2
  1136 premises;
  1137 
  1138 * Isar/Pure: scalable support for case-analysis type proofs: new
  1139 'case' language element refers to local contexts symbolically, as
  1140 produced by certain proof methods; internally, case names are attached
  1141 to theorems as "tags";
  1142 
  1143 * Isar/Pure: theory command 'hide' removes declarations from
  1144 class/type/const name spaces;
  1145 
  1146 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1147 indicate potential overloading;
  1148 
  1149 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1150 
  1151 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1152 "{a,b,c}" instead of {a,b,c};
  1153 
  1154 * Isar/Pure now provides its own version of intro/elim/dest
  1155 attributes; useful for building new logics, but beware of confusion
  1156 with the version in Provers/classical;
  1157 
  1158 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1159 case name 'antecedent';
  1160 
  1161 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1162 to the current context is now done automatically);
  1163 
  1164 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1165 for definining proof methods in ML;
  1166 
  1167 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1168 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1169 most cases, one should have to change intro!! to intro? only);
  1170 replaced "delrule" by "rule del";
  1171 
  1172 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1173 'symmetric' attribute (the latter supercedes [RS sym]);
  1174 
  1175 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1176 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1177 well (including splits);
  1178 
  1179 * Isar/Provers: Simplifier and Classical methods now support all kind
  1180 of modifiers used in the past, including 'cong', 'iff', etc.
  1181 
  1182 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1183 of Simplifier and Classical reasoner);
  1184 
  1185 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1186 now support named cases; major packages (inductive, datatype, primrec,
  1187 recdef) support case names and properly name parameters;
  1188 
  1189 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1190 monotonicity conditions are extracted to be proven at end of
  1191 calculations;
  1192 
  1193 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1194 method anyway;
  1195 
  1196 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1197 split_if split_if_asm; datatype package provides theorems foo.splits =
  1198 foo.split foo.split_asm for each datatype;
  1199 
  1200 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1201 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1202 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1203 use "(cases (simplified))" method in proper proof texts);
  1204 
  1205 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1206 
  1207 * Isar: names of theorems etc. may be natural numbers as well;
  1208 
  1209 * Isar: 'pr' command: optional arguments for goals_limit and
  1210 ProofContext.prems_limit; no longer prints theory contexts, but only
  1211 proof states;
  1212 
  1213 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1214 additional print modes to be specified; e.g. "pr(latex)" will print
  1215 proof state according to the Isabelle LaTeX style;
  1216 
  1217 * Isar: improved support for emulating tactic scripts, including proof
  1218 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1219 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1220 (for HOL datatypes);
  1221 
  1222 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1223 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1224 'proof method scripts' have to be in depth-first order;
  1225 
  1226 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1227 
  1228 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1229 should instead use individual commands for printing items
  1230 (print_commands, print_methods etc.);
  1231 
  1232 * Isar: added 'nothing' --- the empty list of theorems;
  1233 
  1234 
  1235 *** HOL ***
  1236 
  1237 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1238 corresponding virtual machine and a specification of its bytecode
  1239 verifier and a lightweight bytecode verifier, including proofs of
  1240 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1241 Cornelia Pusch (see also the homepage of project Bali at
  1242 http://isabelle.in.tum.de/Bali/);
  1243 
  1244 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1245 Clemens Ballarin;
  1246 
  1247 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1248 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1249 Rasmussen;
  1250 
  1251 * HOL/Lattice: fundamental concepts of lattice theory and order
  1252 structures, including duals, properties of bounds versus algebraic
  1253 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1254 Theorem for complete lattices etc.; may also serve as a demonstration
  1255 for abstract algebraic reasoning using axiomatic type classes, and
  1256 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1257 
  1258 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1259 von Oheimb;
  1260 
  1261 * HOL/IMPP: extension of IMP with local variables and mutually
  1262 recursive procedures, by David von Oheimb;
  1263 
  1264 * HOL/Lambda: converted into new-style theory and document;
  1265 
  1266 * HOL/ex/Multiquote: example of multiple nested quotations and
  1267 anti-quotations -- basically a generalized version of de-Bruijn
  1268 representation; very useful in avoiding lifting of operations;
  1269 
  1270 * HOL/record: added general record equality rule to simpset; fixed
  1271 select-update simplification procedure to handle extended records as
  1272 well; admit "r" as field name;
  1273 
  1274 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1275 other numeric types and also as the identity of groups, rings, etc.;
  1276 
  1277 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1278 Types nat and int belong to this axclass;
  1279 
  1280 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1281    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1282    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1283   two terms #m*u and #n*u are replaced by #(m+n)*u
  1284     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1285   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1286     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1287 
  1288 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1289 powerful prover for predicate logic but knows nothing of clasets; see
  1290 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1291 
  1292 * HOL: new version of "case_tac" subsumes both boolean case split and
  1293 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1294 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1295 
  1296 * HOL: simplification no longer dives into case-expressions: only the
  1297 selector expression is simplified, but not the remaining arms; to
  1298 enable full simplification of case-expressions for datatype t, you may
  1299 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1300 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1301 
  1302 * HOL/recdef: the recursion equations generated by 'recdef' for
  1303 function 'f' are now called f.simps instead of f.rules; if all
  1304 termination conditions are proved automatically, these simplification
  1305 rules are added to the simpset, as in primrec; rules may be named
  1306 individually as well, resulting in a separate list of theorems for
  1307 each equation;
  1308 
  1309 * HOL/While is a new theory that provides a while-combinator. It
  1310 permits the definition of tail-recursive functions without the
  1311 provision of a termination measure. The latter is necessary once the
  1312 invariant proof rule for while is applied.
  1313 
  1314 * HOL: new (overloaded) notation for the set of elements below/above
  1315 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1316 
  1317 * HOL: theorems impI, allI, ballI bound as "strip";
  1318 
  1319 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1320 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1321 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1322 
  1323 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1324 
  1325 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1326 main HOL, but was unused);
  1327 
  1328 * HOL: fewer consts declared as global (e.g. have to refer to
  1329 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1330 
  1331 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1332 in case of overlap with user translations (e.g. judgements over
  1333 tuples); (note that the underlying logical represenation is still
  1334 bogus);
  1335 
  1336 
  1337 *** ZF ***
  1338 
  1339 * ZF: simplification automatically cancels common terms in arithmetic
  1340 expressions over nat and int;
  1341 
  1342 * ZF: new treatment of nat to minimize type-checking: all operators
  1343 coerce their operands to a natural number using the function natify,
  1344 making the algebraic laws unconditional;
  1345 
  1346 * ZF: as above, for int: operators coerce their operands to an integer
  1347 using the function intify;
  1348 
  1349 * ZF: the integer library now contains many of the usual laws for the
  1350 orderings, including $<=, and monotonicity laws for $+ and $*;
  1351 
  1352 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1353 simplification;
  1354 
  1355 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1356 to the simplifier and classical reasoner simultaneously;
  1357 
  1358 
  1359 *** General ***
  1360 
  1361 * Provers: blast_tac now handles actual object-logic rules as
  1362 assumptions; note that auto_tac uses blast_tac internally as well;
  1363 
  1364 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1365 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1366 
  1367 * Provers: delrules now handles destruct rules as well (no longer need
  1368 explicit make_elim);
  1369 
  1370 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1371   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1372 use instead the strong form,
  1373   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1374 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1375 from destruct-rules;
  1376 
  1377 * Provers: Simplifier.easy_setup provides a fast path to basic
  1378 Simplifier setup for new object-logics;
  1379 
  1380 * Pure: AST translation rules no longer require constant head on LHS;
  1381 
  1382 * Pure: improved name spaces: ambiguous output is qualified; support
  1383 for hiding of names;
  1384 
  1385 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1386 XSYMBOL_HOME; no longer need to do manual configuration in most
  1387 situations;
  1388 
  1389 * system: compression of ML heaps images may now be controlled via -c
  1390 option of isabelle and isatool usedir (currently only observed by
  1391 Poly/ML);
  1392 
  1393 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1394 useful for remote X11);
  1395 
  1396 * system: provide TAGS file for Isabelle sources;
  1397 
  1398 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1399 order;
  1400 
  1401 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1402 timing flag supersedes proof_timing and Toplevel.trace;
  1403 
  1404 * ML: new combinators |>> and |>>> for incremental transformations
  1405 with secondary results (e.g. certain theory extensions):
  1406 
  1407 * ML: PureThy.add_defs gets additional argument to indicate potential
  1408 overloading (usually false);
  1409 
  1410 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1411 results;
  1412 
  1413 
  1414 
  1415 New in Isabelle99 (October 1999)
  1416 --------------------------------
  1417 
  1418 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1419 
  1420 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1421 are no longer simplified.  (This allows the simplifier to unfold recursive
  1422 functional programs.)  To restore the old behaviour, declare
  1423 
  1424     Delcongs [if_weak_cong];
  1425 
  1426 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1427 complement;
  1428 
  1429 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1430 
  1431 * HOL/datatype: mutual_induct_tac no longer exists --
  1432   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1433 
  1434 * HOL/typedef: fixed type inference for representing set; type
  1435 arguments now have to occur explicitly on the rhs as type constraints;
  1436 
  1437 * ZF: The con_defs part of an inductive definition may no longer refer
  1438 to constants declared in the same theory;
  1439 
  1440 * HOL, ZF: the function mk_cases, generated by the inductive
  1441 definition package, has lost an argument.  To simplify its result, it
  1442 uses the default simpset instead of a supplied list of theorems.
  1443 
  1444 * HOL/List: the constructors of type list are now Nil and Cons;
  1445 
  1446 * Simplifier: the type of the infix ML functions
  1447         setSSolver addSSolver setSolver addSolver
  1448 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1449 for packaging solvers. A solver is created via
  1450         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1451 where the string argument is only a comment.
  1452 
  1453 
  1454 *** Proof tools ***
  1455 
  1456 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1457 decision procedure for linear arithmetic. Currently it is used for
  1458 types `nat', `int', and `real' in HOL (see below); it can, should and
  1459 will be instantiated for other types and logics as well.
  1460 
  1461 * The simplifier now accepts rewrite rules with flexible heads, eg
  1462      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1463   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1464   matching.
  1465 
  1466 
  1467 *** General ***
  1468 
  1469 * New Isabelle/Isar subsystem provides an alternative to traditional
  1470 tactical theorem proving; together with the ProofGeneral/isar user
  1471 interface it offers an interactive environment for developing human
  1472 readable proof documents (Isar == Intelligible semi-automated
  1473 reasoning); for further information see isatool doc isar-ref,
  1474 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1475 
  1476 * improved and simplified presentation of theories: better HTML markup
  1477 (including colors), graph views in several sizes; isatool usedir now
  1478 provides a proper interface for user theories (via -P option); actual
  1479 document preparation based on (PDF)LaTeX is available as well (for
  1480 new-style theories only); see isatool doc system for more information;
  1481 
  1482 * native support for Proof General, both for classic Isabelle and
  1483 Isabelle/Isar;
  1484 
  1485 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1486 using the graph browser tool;
  1487 
  1488 * Isabelle manuals now also available as PDF;
  1489 
  1490 * theory loader rewritten from scratch (may not be fully
  1491 bug-compatible); old loadpath variable has been replaced by show_path,
  1492 add_path, del_path, reset_path functions; new operations such as
  1493 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1494 isatool doc ref);
  1495 
  1496 * improved isatool install: option -k creates KDE application icon,
  1497 option -p DIR installs standalone binaries;
  1498 
  1499 * added ML_PLATFORM setting (useful for cross-platform installations);
  1500 more robust handling of platform specific ML images for SML/NJ;
  1501 
  1502 * the settings environment is now statically scoped, i.e. it is never
  1503 created again in sub-processes invoked from isabelle, isatool, or
  1504 Isabelle;
  1505 
  1506 * path element specification '~~' refers to '$ISABELLE_HOME';
  1507 
  1508 * in locales, the "assumes" and "defines" parts may be omitted if
  1509 empty;
  1510 
  1511 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1512 long arrows);
  1513 
  1514 * new print_mode "HTML";
  1515 
  1516 * new flag show_tags controls display of tags of theorems (which are
  1517 basically just comments that may be attached by some tools);
  1518 
  1519 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1520 mode and goal output format:
  1521 
  1522 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1523 244c244
  1524 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1525 ---
  1526 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1527 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1528 181c181
  1529 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1530 ---
  1531 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1532 
  1533 * function bind_thms stores lists of theorems (cf. bind_thm);
  1534 
  1535 * new shorthand tactics ftac, eatac, datac, fatac;
  1536 
  1537 * qed (and friends) now accept "" as result name; in that case the
  1538 theorem is not stored, but proper checks and presentation of the
  1539 result still apply;
  1540 
  1541 * theorem database now also indexes constants "Trueprop", "all",
  1542 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1543 
  1544 
  1545 *** HOL ***
  1546 
  1547 ** HOL arithmetic **
  1548 
  1549 * There are now decision procedures for linear arithmetic over nat and
  1550 int:
  1551 
  1552 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1553 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1554 are treated as atomic; subformulae not involving type `nat' or `int'
  1555 are ignored; quantified subformulae are ignored unless they are
  1556 positive universal or negative existential. The tactic has to be
  1557 invoked by hand and can be a little bit slow. In particular, the
  1558 running time is exponential in the number of occurrences of `min' and
  1559 `max', and `-' on `nat'.
  1560 
  1561 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1562 (negated) (in)equalities among the premises and the conclusion into
  1563 account (i.e. no compound formulae) and does not know about `min' and
  1564 `max', and `-' on `nat'. It is fast and is used automatically by the
  1565 simplifier.
  1566 
  1567 NB: At the moment, these decision procedures do not cope with mixed
  1568 nat/int formulae where the two parts interact, such as `m < n ==>
  1569 int(m) < int(n)'.
  1570 
  1571 * HOL/Numeral provides a generic theory of numerals (encoded
  1572 efficiently as bit strings); setup for types nat/int/real is in place;
  1573 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1574 int, existing theories and proof scripts may require a few additional
  1575 type constraints;
  1576 
  1577 * integer division and remainder can now be performed on constant
  1578 arguments;
  1579 
  1580 * many properties of integer multiplication, division and remainder
  1581 are now available;
  1582 
  1583 * An interface to the Stanford Validity Checker (SVC) is available through the
  1584 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1585 are proved automatically.  SVC must be installed separately, and its results
  1586 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1587 invocation of the underlying oracle).  For SVC see
  1588   http://verify.stanford.edu/SVC
  1589 
  1590 * IsaMakefile: the HOL-Real target now builds an actual image;
  1591 
  1592 
  1593 ** HOL misc **
  1594 
  1595 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1596 (in Isabelle/Isar) -- by Gertrud Bauer;
  1597 
  1598 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1599 analysis for assembly languages with subtypes;
  1600 
  1601 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1602 -- avoids syntactic ambiguities and treats state, transition, and
  1603 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1604 changed syntax and (many) tactics;
  1605 
  1606 * HOL/inductive: Now also handles more general introduction rules such
  1607   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1608   theorems are now maintained within the theory (maintained via the
  1609   "mono" attribute);
  1610 
  1611 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1612   (using function types) such as
  1613 
  1614   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1615 
  1616 * HOL/record: record_simproc (part of the default simpset) takes care
  1617 of selectors applied to updated records; record_split_tac is no longer
  1618 part of the default claset; update_defs may now be removed from the
  1619 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1620 
  1621   claset_ref () := claset() addSWrapper record_split_wrapper;
  1622   Delsimprocs [record_simproc]
  1623 
  1624 * HOL/typedef: fixed type inference for representing set; type
  1625 arguments now have to occur explicitly on the rhs as type constraints;
  1626 
  1627 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1628 names rather than an ML expression;
  1629 
  1630 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1631 supplied later.  Program schemes can be defined, such as
  1632     "While B C s = (if B s then While B C (C s) else s)"
  1633 where the well-founded relation can be chosen after B and C have been given.
  1634 
  1635 * HOL/List: the constructors of type list are now Nil and Cons;
  1636 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1637 course, ML tools referring to List.list.op # etc. have to be adapted;
  1638 
  1639 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1640 disabled by default; run isabelle with option -m HOL to get back to
  1641 the original Gordon/HOL-style output;
  1642 
  1643 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1644 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1645 
  1646 * HOL basic syntax simplified (more orthogonal): all variants of
  1647 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1648 Eps operator is provided as well: "SOME x. P[x]";
  1649 
  1650 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1651 
  1652 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1653 thus available for user theories;
  1654 
  1655 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1656 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1657 time;
  1658 
  1659 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1660 several times and then mp;
  1661 
  1662 
  1663 *** LK ***
  1664 
  1665 * the notation <<...>> is now available as a notation for sequences of
  1666 formulas;
  1667 
  1668 * the simplifier is now installed
  1669 
  1670 * the axiom system has been generalized (thanks to Soren Heilmann)
  1671 
  1672 * the classical reasoner now has a default rule database
  1673 
  1674 
  1675 *** ZF ***
  1676 
  1677 * new primrec section allows primitive recursive functions to be given
  1678 directly (as in HOL) over datatypes and the natural numbers;
  1679 
  1680 * new tactics induct_tac and exhaust_tac for induction (or case
  1681 analysis) over datatypes and the natural numbers;
  1682 
  1683 * the datatype declaration of type T now defines the recursor T_rec;
  1684 
  1685 * simplification automatically does freeness reasoning for datatype
  1686 constructors;
  1687 
  1688 * automatic type-inference, with AddTCs command to insert new
  1689 type-checking rules;
  1690 
  1691 * datatype introduction rules are now added as Safe Introduction rules
  1692 to the claset;
  1693 
  1694 * the syntax "if P then x else y" is now available in addition to
  1695 if(P,x,y);
  1696 
  1697 
  1698 *** Internal programming interfaces ***
  1699 
  1700 * tuned simplifier trace output; new flag debug_simp;
  1701 
  1702 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1703 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1704 
  1705 * AxClass.axclass_tac lost the theory argument;
  1706 
  1707 * tuned current_goals_markers semantics: begin / end goal avoids
  1708 printing empty lines;
  1709 
  1710 * removed prs and prs_fn hook, which was broken because it did not
  1711 include \n in its semantics, forcing writeln to add one
  1712 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1713 string -> unit if you really want to output text without newline;
  1714 
  1715 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1716 plain output, interface builders may have to enable 'isabelle_font'
  1717 mode to get Isabelle font glyphs as before;
  1718 
  1719 * refined token_translation interface; INCOMPATIBILITY: output length
  1720 now of type real instead of int;
  1721 
  1722 * theory loader actions may be traced via new ThyInfo.add_hook
  1723 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1724 your own database of information attached to *whole* theories -- as
  1725 opposed to intra-theory data slots offered via TheoryDataFun;
  1726 
  1727 * proper handling of dangling sort hypotheses (at last!);
  1728 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1729 extra sort hypotheses that can be witnessed from the type signature;
  1730 the force_strip_shyps flag is gone, any remaining shyps are simply
  1731 left in the theorem (with a warning issued by strip_shyps_warning);
  1732 
  1733 
  1734 
  1735 New in Isabelle98-1 (October 1998)
  1736 ----------------------------------
  1737 
  1738 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1739 
  1740 * several changes of automated proof tools;
  1741 
  1742 * HOL: major changes to the inductive and datatype packages, including
  1743 some minor incompatibilities of theory syntax;
  1744 
  1745 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1746 called `inj_on';
  1747 
  1748 * HOL: removed duplicate thms in Arith:
  1749   less_imp_add_less  should be replaced by  trans_less_add1
  1750   le_imp_add_le      should be replaced by  trans_le_add1
  1751 
  1752 * HOL: unary minus is now overloaded (new type constraints may be
  1753 required);
  1754 
  1755 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1756 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1757 now taken as an integer constant.
  1758 
  1759 * Pure: ML function 'theory_of' renamed to 'theory';
  1760 
  1761 
  1762 *** Proof tools ***
  1763 
  1764 * Simplifier:
  1765   1. Asm_full_simp_tac is now more aggressive.
  1766      1. It will sometimes reorient premises if that increases their power to
  1767         simplify.
  1768      2. It does no longer proceed strictly from left to right but may also
  1769         rotate premises to achieve further simplification.
  1770      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1771      old Asm_full_simp_tac in that it does not rotate premises.
  1772   2. The simplifier now knows a little bit about nat-arithmetic.
  1773 
  1774 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1775 allows for selected deletion of wrappers, by introduction of names for
  1776 wrapper functionals.  This implies that addbefore, addSbefore,
  1777 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1778 and that adding two tactics with the same name overwrites the first
  1779 one (emitting a warning).
  1780   type wrapper = (int -> tactic) -> (int -> tactic)
  1781   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1782   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1783   delWrapper, delSWrapper: claset *  string            -> claset
  1784   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1785 
  1786 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1787 semantics; addbefore now affects only the unsafe part of step_tac
  1788 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1789 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1790 by Force_tac;
  1791 
  1792 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1793 compWrapper; added safe wrapper (and access functions for it);
  1794 
  1795 * HOL/split_all_tac is now much faster and fails if there is nothing
  1796 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1797 and the names of the automatically generated variables have changed.
  1798 split_all_tac has moved within claset() from unsafe wrappers to safe
  1799 wrappers, which means that !!-bound variables are split much more
  1800 aggressively, and safe_tac and clarify_tac now split such variables.
  1801 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1802 Note: the same holds for record_split_tac, which does the job of
  1803 split_all_tac for record fields.
  1804 
  1805 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1806 permanently to the default simpset using Addsplits just like
  1807 Addsimps. They can be removed via Delsplits just like
  1808 Delsimps. Lower-case versions are also available.
  1809 
  1810 * HOL/Simplifier: The rule split_if is now part of the default
  1811 simpset. This means that the simplifier will eliminate all occurrences
  1812 of if-then-else in the conclusion of a goal. To prevent this, you can
  1813 either remove split_if completely from the default simpset by
  1814 `Delsplits [split_if]' or remove it in a specific call of the
  1815 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1816 other case splitting rules to/from the default simpset: every datatype
  1817 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1818 t is the name of the datatype).
  1819 
  1820 * Classical reasoner / Simplifier combination: new force_tac (and
  1821 derivatives Force_tac, force) combines rewriting and classical
  1822 reasoning (and whatever other tools) similarly to auto_tac, but is
  1823 aimed to solve the given subgoal completely.
  1824 
  1825 
  1826 *** General ***
  1827 
  1828 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1829 and `goalw': the theory is no longer needed as an explicit argument -
  1830 the current theory context is used; assumptions are no longer returned
  1831 at the ML-level unless one of them starts with ==> or !!; it is
  1832 recommended to convert to these new commands using isatool fixgoal
  1833 (backup your sources first!);
  1834 
  1835 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1836 the current theory context, and 'theory' to lookup stored theories;
  1837 
  1838 * new theory section 'locale' for declaring constants, assumptions and
  1839 definitions that have local scope;
  1840 
  1841 * new theory section 'nonterminals' for purely syntactic types;
  1842 
  1843 * new theory section 'setup' for generic ML setup functions
  1844 (e.g. package initialization);
  1845 
  1846 * the distribution now includes Isabelle icons: see
  1847 lib/logo/isabelle-{small,tiny}.xpm;
  1848 
  1849 * isatool install - install binaries with absolute references to
  1850 ISABELLE_HOME/bin;
  1851 
  1852 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1853 
  1854 * print mode 'emacs' reserved for Isamode;
  1855 
  1856 * support multiple print (ast) translations per constant name;
  1857 
  1858 * theorems involving oracles are now printed with a suffixed [!];
  1859 
  1860 
  1861 *** HOL ***
  1862 
  1863 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1864 
  1865 * HOL/inductive package reorganized and improved: now supports mutual
  1866 definitions such as
  1867 
  1868   inductive EVEN ODD
  1869     intrs
  1870       null "0 : EVEN"
  1871       oddI "n : EVEN ==> Suc n : ODD"
  1872       evenI "n : ODD ==> Suc n : EVEN"
  1873 
  1874 new theorem list "elims" contains an elimination rule for each of the
  1875 recursive sets; inductive definitions now handle disjunctive premises
  1876 correctly (also ZF);
  1877 
  1878 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1879 "mutual_induct" no longer exists - the induction rule is always
  1880 contained in "induct";
  1881 
  1882 
  1883 * HOL/datatype package re-implemented and greatly improved: now
  1884 supports mutually recursive datatypes such as
  1885 
  1886   datatype
  1887     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1888             | SUM ('a aexp) ('a aexp)
  1889             | DIFF ('a aexp) ('a aexp)
  1890             | NUM 'a
  1891   and
  1892     'a bexp = LESS ('a aexp) ('a aexp)
  1893             | AND ('a bexp) ('a bexp)
  1894             | OR ('a bexp) ('a bexp)
  1895 
  1896 as well as indirectly recursive datatypes such as
  1897 
  1898   datatype
  1899     ('a, 'b) term = Var 'a
  1900                   | App 'b ((('a, 'b) term) list)
  1901 
  1902 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1903 induction on mutually / indirectly recursive datatypes.
  1904 
  1905 Primrec equations are now stored in theory and can be accessed via
  1906 <function_name>.simps.
  1907 
  1908 INCOMPATIBILITIES:
  1909 
  1910   - Theories using datatypes must now have theory Datatype as an
  1911     ancestor.
  1912   - The specific <typename>.induct_tac no longer exists - use the
  1913     generic induct_tac instead.
  1914   - natE has been renamed to nat.exhaust - use exhaust_tac
  1915     instead of res_inst_tac ... natE. Note that the variable
  1916     names in nat.exhaust differ from the names in natE, this
  1917     may cause some "fragile" proofs to fail.
  1918   - The theorems split_<typename>_case and split_<typename>_case_asm
  1919     have been renamed to <typename>.split and <typename>.split_asm.
  1920   - Since default sorts of type variables are now handled correctly,
  1921     some datatype definitions may have to be annotated with explicit
  1922     sort constraints.
  1923   - Primrec definitions no longer require function name and type
  1924     of recursive argument.
  1925 
  1926 Consider using isatool fixdatatype to adapt your theories and proof
  1927 scripts to the new package (backup your sources first!).
  1928 
  1929 
  1930 * HOL/record package: considerably improved implementation; now
  1931 includes concrete syntax for record types, terms, updates; theorems
  1932 for surjective pairing and splitting !!-bound record variables; proof
  1933 support is as follows:
  1934 
  1935   1) standard conversions (selectors or updates applied to record
  1936 constructor terms) are part of the standard simpset;
  1937 
  1938   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1939 made part of standard simpset and claset via addIffs;
  1940 
  1941   3) a tactic for record field splitting (record_split_tac) is part of
  1942 the standard claset (addSWrapper);
  1943 
  1944 To get a better idea about these rules you may retrieve them via
  1945 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1946 the name of your record type.
  1947 
  1948 The split tactic 3) conceptually simplifies by the following rule:
  1949 
  1950   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1951 
  1952 Thus any record variable that is bound by meta-all will automatically
  1953 blow up into some record constructor term, consequently the
  1954 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1955 solve record problems automatically.
  1956 
  1957 
  1958 * reorganized the main HOL image: HOL/Integ and String loaded by
  1959 default; theory Main includes everything;
  1960 
  1961 * automatic simplification of integer sums and comparisons, using cancellation;
  1962 
  1963 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1964 
  1965 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1966 
  1967 * many new identities for unions, intersections, set difference, etc.;
  1968 
  1969 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1970 called split_if, split_split, split_sum_case and split_nat_case (to go
  1971 with add/delsplits);
  1972 
  1973 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1974 (?x::unit) = (); this is made part of the default simpset, which COULD
  1975 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1976 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1977 unit_abs_eta_conv is added in order to counter the effect of
  1978 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1979 %u.f();
  1980 
  1981 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1982 makes more sense);
  1983 
  1984 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1985   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1986   disjointness reasoning but breaking a few old proofs.
  1987 
  1988 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1989 to 'converse' from 'inverse' (for compatibility with ZF and some
  1990 literature);
  1991 
  1992 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  1993 the well-founded relation;
  1994 
  1995 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  1996     Compl A.  The "Compl" syntax remains available as input syntax for this
  1997     release ONLY.
  1998 
  1999 * HOL/Update: new theory of function updates:
  2000     f(a:=b) == %x. if x=a then b else f x
  2001 may also be iterated as in f(a:=b,c:=d,...);
  2002 
  2003 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2004 
  2005 * HOL/List:
  2006   - new function list_update written xs[i:=v] that updates the i-th
  2007     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2008   - new function `upt' written [i..j(] which generates the list
  2009     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2010     bound write [i..j], which is a shorthand for [i..j+1(].
  2011   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2012 
  2013 * HOL/Arith:
  2014   - removed 'pred' (predecessor) function;
  2015   - generalized some theorems about n-1;
  2016   - many new laws about "div" and "mod";
  2017   - new laws about greatest common divisors (see theory ex/Primes);
  2018 
  2019 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2020 instead of "inverse";
  2021 
  2022 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2023   of the multiset ordering;
  2024 
  2025 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2026   (not included by default);
  2027 
  2028 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2029 
  2030 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2031   programs, i.e. different program variables may have different types.
  2032 
  2033 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2034   [previously, this check worked only if the rewrite rule was unconditional]
  2035   Now rew can involve either definitions or equalities (either == or =).
  2036 
  2037 
  2038 *** ZF ***
  2039 
  2040 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2041   only the theorems proved on ZF.ML;
  2042 
  2043 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2044   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2045   disjointness reasoning but breaking a few old proofs.
  2046 
  2047 * ZF/Update: new theory of function updates
  2048     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2049   may also be iterated as in f(a:=b,c:=d,...);
  2050 
  2051 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2052 
  2053 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2054   [previously, this check worked only if the rewrite rule was unconditional]
  2055   Now rew can involve either definitions or equalities (either == or =).
  2056 
  2057 * case_tac provided for compatibility with HOL
  2058     (like the old excluded_middle_tac, but with subgoals swapped)
  2059 
  2060 
  2061 *** Internal programming interfaces ***
  2062 
  2063 * Pure: several new basic modules made available for general use, see
  2064 also src/Pure/README;
  2065 
  2066 * improved the theory data mechanism to support encapsulation (data
  2067 kind name replaced by private Object.kind, acting as authorization
  2068 key); new type-safe user interface via functor TheoryDataFun; generic
  2069 print_data function becomes basically useless;
  2070 
  2071 * removed global_names compatibility flag -- all theory declarations
  2072 are qualified by default;
  2073 
  2074 * module Pure/Syntax now offers quote / antiquote translation
  2075 functions (useful for Hoare logic etc. with implicit dependencies);
  2076 see HOL/ex/Antiquote for an example use;
  2077 
  2078 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2079 cterm -> thm;
  2080 
  2081 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2082 subgoal;
  2083 
  2084 * Display.print_goals function moved to Locale.print_goals;
  2085 
  2086 * standard print function for goals supports current_goals_markers
  2087 variable for marking begin of proof, end of proof, start of goal; the
  2088 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2089 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2090 for example;
  2091 
  2092 
  2093 
  2094 New in Isabelle98 (January 1998)
  2095 --------------------------------
  2096 
  2097 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2098 
  2099 * changed lexical syntax of terms / types: dots made part of long
  2100 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2101 
  2102 * simpset (and claset) reference variable replaced by functions
  2103 simpset / simpset_ref;
  2104 
  2105 * no longer supports theory aliases (via merge) and non-trivial
  2106 implicit merge of thms' signatures;
  2107 
  2108 * most internal names of constants changed due to qualified names;
  2109 
  2110 * changed Pure/Sequence interface (see Pure/seq.ML);
  2111 
  2112 
  2113 *** General Changes ***
  2114 
  2115 * hierachically structured name spaces (for consts, types, axms, thms
  2116 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2117 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2118 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2119 long_names for fully qualified output names; NOTE: ML programs
  2120 (special tactics, packages etc.) referring to internal names may have
  2121 to be adapted to cope with fully qualified names; in case of severe
  2122 backward campatibility problems try setting 'global_names' at compile
  2123 time to have enrything declared within a flat name space; one may also
  2124 fine tune name declarations in theories via the 'global' and 'local'
  2125 section;
  2126 
  2127 * reimplemented the implicit simpset and claset using the new anytype
  2128 data filed in signatures; references simpset:simpset ref etc. are
  2129 replaced by functions simpset:unit->simpset and
  2130 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2131 to patch your ML files accordingly;
  2132 
  2133 * HTML output now includes theory graph data for display with Java
  2134 applet or isatool browser; data generated automatically via isatool
  2135 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2136 
  2137 * defs may now be conditional; improved rewrite_goals_tac to handle
  2138 conditional equations;
  2139 
  2140 * defs now admits additional type arguments, using TYPE('a) syntax;
  2141 
  2142 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2143 creates a new theory node; implicit merge of thms' signatures is
  2144 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2145 transfer:theory->thm->thm in (rare) cases;
  2146 
  2147 * improved handling of draft signatures / theories; draft thms (and
  2148 ctyps, cterms) are automatically promoted to real ones;
  2149 
  2150 * slightly changed interfaces for oracles: admit many per theory, named
  2151 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2152 
  2153 * print_goals: optional output of const types (set show_consts and
  2154 show_types);
  2155 
  2156 * improved output of warnings (###) and errors (***);
  2157 
  2158 * subgoal_tac displays a warning if the new subgoal has type variables;
  2159 
  2160 * removed old README and Makefiles;
  2161 
  2162 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2163 
  2164 * removed obsolete init_pps and init_database;
  2165 
  2166 * deleted the obsolete tactical STATE, which was declared by
  2167     fun STATE tacfun st = tacfun st st;
  2168 
  2169 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2170 (which abbreviates $HOME);
  2171 
  2172 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2173 use isatool fixseq to adapt your ML programs (this works for fully
  2174 qualified references to the Sequence structure only!);
  2175 
  2176 * use_thy no longer requires writable current directory; it always
  2177 reloads .ML *and* .thy file, if either one is out of date;
  2178 
  2179 
  2180 *** Classical Reasoner ***
  2181 
  2182 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2183 tactics that use classical reasoning to simplify a subgoal without
  2184 splitting it into several subgoals;
  2185 
  2186 * Safe_tac: like safe_tac but uses the default claset;
  2187 
  2188 
  2189 *** Simplifier ***
  2190 
  2191 * added simplification meta rules:
  2192     (asm_)(full_)simplify: simpset -> thm -> thm;
  2193 
  2194 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2195 logics (again);
  2196 
  2197 * added prems argument to simplification procedures;
  2198 
  2199 * HOL, FOL, ZF: added infix function `addsplits':
  2200   instead of `<simpset> setloop (split_tac <thms>)'
  2201   you can simply write `<simpset> addsplits <thms>'
  2202 
  2203 
  2204 *** Syntax ***
  2205 
  2206 * TYPE('a) syntax for type reflection terms;
  2207 
  2208 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2209 
  2210 * pretty printer: changed order of mixfix annotation preference (again!);
  2211 
  2212 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2213 
  2214 
  2215 *** HOL ***
  2216 
  2217 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2218   with `addloop' of the simplifier to faciliate case splitting in premises.
  2219 
  2220 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2221 
  2222 * HOL/Auth: new protocol proofs including some for the Internet
  2223   protocol TLS;
  2224 
  2225 * HOL/Map: new theory of `maps' a la VDM;
  2226 
  2227 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2228 cancelling out common nat summands from =, <, <= (in)equalities, or
  2229 differences; simplification procedures nat_cancel_factor for
  2230 cancelling common factor from =, <, <= (in)equalities over natural
  2231 sums; nat_cancel contains both kinds of procedures, it is installed by
  2232 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2233 
  2234 * HOL/simplifier: terms of the form
  2235   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2236   are rewritten to
  2237   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2238   and those of the form
  2239   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2240   are rewritten to
  2241   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2242 
  2243 * HOL/datatype
  2244   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2245 
  2246   P(t_case f1 ... fn x) =
  2247      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2248         ...
  2249        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2250      )
  2251 
  2252   and a theorem `split_t_case_asm' of the form
  2253 
  2254   P(t_case f1 ... fn x) =
  2255     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2256         ...
  2257        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2258      )
  2259   which can be added to a simpset via `addsplits'. The existing theorems
  2260   expand_list_case and expand_option_case have been renamed to
  2261   split_list_case and split_option_case.
  2262 
  2263 * HOL/Arithmetic:
  2264   - `pred n' is automatically converted to `n-1'.
  2265     Users are strongly encouraged not to use `pred' any longer,
  2266     because it will disappear altogether at some point.
  2267   - Users are strongly encouraged to write "0 < n" rather than
  2268     "n ~= 0". Theorems and proof tools have been modified towards this
  2269     `standard'.
  2270 
  2271 * HOL/Lists:
  2272   the function "set_of_list" has been renamed "set" (and its theorems too);
  2273   the function "nth" now takes its arguments in the reverse order and
  2274   has acquired the infix notation "!" as in "xs!n".
  2275 
  2276 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2277 
  2278 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2279   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2280 
  2281 * HOL/record: extensible records with schematic structural subtyping
  2282 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2283 still lacks various theorems and concrete record syntax;
  2284 
  2285 
  2286 *** HOLCF ***
  2287 
  2288 * removed "axioms" and "generated by" sections;
  2289 
  2290 * replaced "ops" section by extended "consts" section, which is capable of
  2291   handling the continuous function space "->" directly;
  2292 
  2293 * domain package:
  2294   . proves theorems immediately and stores them in the theory,
  2295   . creates hierachical name space,
  2296   . now uses normal mixfix annotations (instead of cinfix...),
  2297   . minor changes to some names and values (for consistency),
  2298   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2299   . separator between mutual domain defs: changed "," to "and",
  2300   . improved handling of sort constraints;  now they have to
  2301     appear on the left-hand side of the equations only;
  2302 
  2303 * fixed LAM <x,y,zs>.b syntax;
  2304 
  2305 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2306 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2307 
  2308 
  2309 *** FOL and ZF ***
  2310 
  2311 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2312   with `addloop' of the simplifier to faciliate case splitting in premises.
  2313 
  2314 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2315 in HOL, they strip ALL and --> from proved theorems;
  2316 
  2317 
  2318 
  2319 New in Isabelle94-8 (May 1997)
  2320 ------------------------------
  2321 
  2322 *** General Changes ***
  2323 
  2324 * new utilities to build / run / maintain Isabelle etc. (in parts
  2325 still somewhat experimental); old Makefiles etc. still functional;
  2326 
  2327 * new 'Isabelle System Manual';
  2328 
  2329 * INSTALL text, together with ./configure and ./build scripts;
  2330 
  2331 * reimplemented type inference for greater efficiency, better error
  2332 messages and clean internal interface;
  2333 
  2334 * prlim command for dealing with lots of subgoals (an easier way of
  2335 setting goals_limit);
  2336 
  2337 
  2338 *** Syntax ***
  2339 
  2340 * supports alternative (named) syntax tables (parser and pretty
  2341 printer); internal interface is provided by add_modesyntax(_i);
  2342 
  2343 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2344 be used in conjunction with the Isabelle symbol font; uses the
  2345 "symbols" syntax table;
  2346 
  2347 * added token_translation interface (may translate name tokens in
  2348 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2349 the current print_mode); IMPORTANT: user print translation functions
  2350 are responsible for marking newly introduced bounds
  2351 (Syntax.mark_boundT);
  2352 
  2353 * token translations for modes "xterm" and "xterm_color" that display
  2354 names in bold, underline etc. or colors (which requires a color
  2355 version of xterm);
  2356 
  2357 * infixes may now be declared with names independent of their syntax;
  2358 
  2359 * added typed_print_translation (like print_translation, but may
  2360 access type of constant);
  2361 
  2362 
  2363 *** Classical Reasoner ***
  2364 
  2365 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2366 some limitations.  Blast_tac...
  2367   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2368   + ignores elimination rules that don't have the correct format
  2369         (the conclusion MUST be a formula variable)
  2370   + ignores types, which can make HOL proofs fail
  2371   + rules must not require higher-order unification, e.g. apply_type in ZF
  2372     [message "Function Var's argument not a bound variable" relates to this]
  2373   + its proof strategy is more general but can actually be slower
  2374 
  2375 * substitution with equality assumptions no longer permutes other
  2376 assumptions;
  2377 
  2378 * minor changes in semantics of addafter (now called addaltern); renamed
  2379 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2380 (and access functions for it);
  2381 
  2382 * improved combination of classical reasoner and simplifier:
  2383   + functions for handling clasimpsets
  2384   + improvement of addss: now the simplifier is called _after_ the
  2385     safe steps.
  2386   + safe variant of addss called addSss: uses safe simplifications
  2387     _during_ the safe steps. It is more complete as it allows multiple
  2388     instantiations of unknowns (e.g. with slow_tac).
  2389 
  2390 *** Simplifier ***
  2391 
  2392 * added interface for simplification procedures (functions that
  2393 produce *proven* rewrite rules on the fly, depending on current
  2394 redex);
  2395 
  2396 * ordering on terms as parameter (used for ordered rewriting);
  2397 
  2398 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2399 
  2400 * the solver is now split into a safe and an unsafe part.
  2401 This should be invisible for the normal user, except that the
  2402 functions setsolver and addsolver have been renamed to setSolver and
  2403 addSolver; added safe_asm_full_simp_tac;
  2404 
  2405 
  2406 *** HOL ***
  2407 
  2408 * a generic induction tactic `induct_tac' which works for all datatypes and
  2409 also for type `nat';
  2410 
  2411 * a generic case distinction tactic `exhaust_tac' which works for all
  2412 datatypes and also for type `nat';
  2413 
  2414 * each datatype comes with a function `size';
  2415 
  2416 * patterns in case expressions allow tuple patterns as arguments to
  2417 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2418 
  2419 * primrec now also works with type nat;
  2420 
  2421 * recdef: a new declaration form, allows general recursive functions to be
  2422 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2423 
  2424 * the constant for negation has been renamed from "not" to "Not" to
  2425 harmonize with FOL, ZF, LK, etc.;
  2426 
  2427 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2428 infinite lists;
  2429 
  2430 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2431 
  2432 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2433 problems in commutative rings, using axiomatic type classes for + and *;
  2434 
  2435 * more examples in HOL/MiniML and HOL/Auth;
  2436 
  2437 * more default rewrite rules for quantifiers, union/intersection;
  2438 
  2439 * a new constant `arbitrary == @x.False';
  2440 
  2441 * HOLCF/IOA replaces old HOL/IOA;
  2442 
  2443 * HOLCF changes: derived all rules and arities
  2444   + axiomatic type classes instead of classes
  2445   + typedef instead of faking type definitions
  2446   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2447   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2448   + eliminated the types void, one, tr
  2449   + use unit lift and bool lift (with translations) instead of one and tr
  2450   + eliminated blift from Lift3.thy (use Def instead of blift)
  2451   all eliminated rules are derived as theorems --> no visible changes ;
  2452 
  2453 
  2454 *** ZF ***
  2455 
  2456 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2457 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2458 as ZF_cs addSIs [equalityI];
  2459 
  2460 
  2461 
  2462 New in Isabelle94-7 (November 96)
  2463 ---------------------------------
  2464 
  2465 * allowing negative levels (as offsets) in prlev and choplev;
  2466 
  2467 * super-linear speedup for large simplifications;
  2468 
  2469 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2470 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2471 FAIL); can suppress it using the command Delsimps (ex_simps @
  2472 all_simps); De Morgan laws are also now included, by default;
  2473 
  2474 * improved printing of ==>  :  ~:
  2475 
  2476 * new object-logic "Sequents" adds linear logic, while replacing LK
  2477 and Modal (thanks to Sara Kalvala);
  2478 
  2479 * HOL/Auth: correctness proofs for authentication protocols;
  2480 
  2481 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2482 examples on HOL/Auth);
  2483 
  2484 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2485 the rewriter and classical reasoner simultaneously;
  2486 
  2487 * function uresult no longer returns theorems in "standard" format;
  2488 regain previous version by: val uresult = standard o uresult;
  2489 
  2490 
  2491 
  2492 New in Isabelle94-6
  2493 -------------------
  2494 
  2495 * oracles -- these establish an interface between Isabelle and trusted
  2496 external reasoners, which may deliver results as theorems;
  2497 
  2498 * proof objects (in particular record all uses of oracles);
  2499 
  2500 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2501 
  2502 * "constdefs" section in theory files;
  2503 
  2504 * "primrec" section (HOL) no longer requires names;
  2505 
  2506 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2507 
  2508 
  2509 
  2510 New in Isabelle94-5
  2511 -------------------
  2512 
  2513 * reduced space requirements;
  2514 
  2515 * automatic HTML generation from theories;
  2516 
  2517 * theory files no longer require "..." (quotes) around most types;
  2518 
  2519 * new examples, including two proofs of the Church-Rosser theorem;
  2520 
  2521 * non-curried (1994) version of HOL is no longer distributed;
  2522 
  2523 
  2524 
  2525 New in Isabelle94-4
  2526 -------------------
  2527 
  2528 * greatly reduced space requirements;
  2529 
  2530 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2531 
  2532 * searchable theorem database (see the section "Retrieving theorems" on
  2533 page 8 of the Reference Manual);
  2534 
  2535 * new examples, including Grabczewski's monumental case study of the
  2536 Axiom of Choice;
  2537 
  2538 * The previous version of HOL renamed to Old_HOL;
  2539 
  2540 * The new version of HOL (previously called CHOL) uses a curried syntax
  2541 for functions.  Application looks like f a b instead of f(a,b);
  2542 
  2543 * Mutually recursive inductive definitions finally work in HOL;
  2544 
  2545 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2546 translates to the operator "split";
  2547 
  2548 
  2549 
  2550 New in Isabelle94-3
  2551 -------------------
  2552 
  2553 * new infix operator, addss, allowing the classical reasoner to
  2554 perform simplification at each step of its search.  Example:
  2555         fast_tac (cs addss ss)
  2556 
  2557 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2558 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2559 look like (a,b) instead of <a,b>;
  2560 
  2561 * PLEASE NOTE: CHOL will eventually replace HOL!
  2562 
  2563 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2564 It translates to the operator "split".  A new theory of integers is available;
  2565 
  2566 * In ZF, integer numerals now denote two's-complement binary integers.
  2567 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2568 
  2569 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2570 of the Axiom of Choice;
  2571 
  2572 
  2573 
  2574 New in Isabelle94-2
  2575 -------------------
  2576 
  2577 * Significantly faster resolution;
  2578 
  2579 * the different sections in a .thy file can now be mixed and repeated
  2580 freely;
  2581 
  2582 * Database of theorems for FOL, HOL and ZF.  New
  2583 commands including qed, qed_goal and bind_thm store theorems in the database.
  2584 
  2585 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2586 a given theory (thms_of), or find out what theory a theorem was proved in
  2587 (theory_of_thm);
  2588 
  2589 * Bugs fixed in the inductive definition and datatype packages;
  2590 
  2591 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2592 and HOL_dup_cs obsolete;
  2593 
  2594 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2595 have been removed;
  2596 
  2597 * Simpler definition of function space in ZF;
  2598 
  2599 * new results about cardinal and ordinal arithmetic in ZF;
  2600 
  2601 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2602 types;
  2603 
  2604 
  2605 $Id$