NEWS
author berghofe
Fri Apr 16 19:04:17 2004 +0200 (2004-04-16)
changeset 14602 e06ded775eca
parent 14572 1408d312d3a9
child 14606 0be6c11e7128
permissions -rw-r--r--
Added entry for quickcheck command.
     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 * 'quickcheck' command: Allows to find counterexamples by evaluating
   170   formulae under an assignment of free variables to random values.
   171   In contrast to 'refute', it can deal with inductive datatypes,
   172   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   173   for examples.
   174 
   175 *** HOLCF ***
   176 
   177 * Streams now come with concatenation and are part of the HOLCF image
   178 
   179 
   180 
   181 New in Isabelle2003 (May 2003)
   182 --------------------------------
   183 
   184 *** General ***
   185 
   186 * Provers/simplifier:
   187 
   188   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   189     Assumptions are now subject to complete mutual simplification,
   190     not just from left to right. The simplifier now preserves
   191     the order of assumptions.
   192 
   193     Potential INCOMPATIBILITY:
   194 
   195     -- simp sometimes diverges where the old version did
   196        not, e.g. invoking simp on the goal
   197 
   198         [| P (f x); y = x; f x = f y |] ==> Q
   199 
   200        now gives rise to the infinite reduction sequence
   201 
   202         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   203 
   204        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   205        kind of problem.
   206 
   207     -- Tactics combining classical reasoner and simplification (such as auto)
   208        are also affected by this change, because many of them rely on
   209        simp. They may sometimes diverge as well or yield a different numbers
   210        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   211        in case of problems. Sometimes subsequent calls to the classical
   212        reasoner will fail because a preceeding call to the simplifier too
   213        eagerly simplified the goal, e.g. deleted redundant premises.
   214 
   215   - The simplifier trace now shows the names of the applied rewrite rules
   216 
   217   - You can limit the number of recursive invocations of the simplifier
   218     during conditional rewriting (where the simplifie tries to solve the
   219     conditions before applying the rewrite rule):
   220     ML "simp_depth_limit := n"
   221     where n is an integer. Thus you can force termination where previously
   222     the simplifier would diverge.
   223 
   224   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   225 
   226   - No longer aborts on failed congruence proof.  Instead, the
   227     congruence is ignored.
   228 
   229 * Pure: New generic framework for extracting programs from constructive
   230   proofs. See HOL/Extraction.thy for an example instantiation, as well
   231   as HOL/Extraction for some case studies.
   232 
   233 * Pure: The main goal of the proof state is no longer shown by default, only
   234 the subgoals. This behaviour is controlled by a new flag.
   235    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   236 (ML: Proof.show_main_goal).
   237 
   238 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   239 rules whose conclusion matches subgoal 1:
   240       PG menu: Isabelle/Isar -> Show me -> matching rules
   241 The rules are ordered by how closely they match the subgoal.
   242 In particular, rules that solve a subgoal outright are displayed first
   243 (or rather last, the way they are printed).
   244 (ML: ProofGeneral.print_intros())
   245 
   246 * Pure: New flag trace_unify_fail causes unification to print
   247 diagnostic information (PG: in trace buffer) when it fails. This is
   248 useful for figuring out why single step proofs like rule, erule or
   249 assumption failed.
   250 
   251 * Pure: Locale specifications now produce predicate definitions
   252 according to the body of text (covering assumptions modulo local
   253 definitions); predicate "loc_axioms" covers newly introduced text,
   254 while "loc" is cumulative wrt. all included locale expressions; the
   255 latter view is presented only on export into the global theory
   256 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   257 on the old view without predicates;
   258 
   259 * Pure: predefined locales "var" and "struct" are useful for sharing
   260 parameters (as in CASL, for example); just specify something like
   261 ``var x + var y + struct M'' as import;
   262 
   263 * Pure: improved thms_containing: proper indexing of facts instead of
   264 raw theorems; check validity of results wrt. current name space;
   265 include local facts of proof configuration (also covers active
   266 locales), cover fixed variables in index; may use "_" in term
   267 specification; an optional limit for the number of printed facts may
   268 be given (the default is 40);
   269 
   270 * Pure: disallow duplicate fact bindings within new-style theory files
   271 (batch-mode only);
   272 
   273 * Provers: improved induct method: assumptions introduced by case
   274 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   275 the goal statement); "foo" still refers to all facts collectively;
   276 
   277 * Provers: the function blast.overloaded has been removed: all constants
   278 are regarded as potentially overloaded, which improves robustness in exchange
   279 for slight decrease in efficiency;
   280 
   281 * Provers/linorder: New generic prover for transitivity reasoning over
   282 linear orders.  Note: this prover is not efficient!
   283 
   284 * Isar: preview of problems to finish 'show' now produce an error
   285 rather than just a warning (in interactive mode);
   286 
   287 
   288 *** HOL ***
   289 
   290 * arith(_tac)
   291 
   292  - Produces a counter example if it cannot prove a goal.
   293    Note that the counter example may be spurious if the goal is not a formula
   294    of quantifier-free linear arithmetic.
   295    In ProofGeneral the counter example appears in the trace buffer.
   296 
   297  - Knows about div k and mod k where k is a numeral of type nat or int.
   298 
   299  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   300    linear arithmetic fails. This takes account of quantifiers and divisibility.
   301    Presburger arithmetic can also be called explicitly via presburger(_tac). 
   302 
   303 * simp's arithmetic capabilities have been enhanced a bit: it now
   304 takes ~= in premises into account (by performing a case split);
   305 
   306 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   307 are distributed over a sum of terms;
   308 
   309 * New tactic "trans_tac" and method "trans" instantiate
   310 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   311 "<=", "<" and "="). 
   312 
   313 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main 
   314 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   315 
   316 * 'typedef' command has new option "open" to suppress the set
   317 definition;
   318 
   319 * functions Min and Max on finite sets have been introduced (theory
   320 Finite_Set);
   321 
   322 * attribute [symmetric] now works for relations as well; it turns
   323 (x,y) : R^-1 into (y,x) : R, and vice versa;
   324 
   325 * induct over a !!-quantified statement (say !!x1..xn):
   326   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   327 
   328 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   329 %x. None. Warning: empty_def now refers to the previously hidden definition
   330 of the empty set.
   331 
   332 * Algebra: formalization of classical algebra.  Intended as base for
   333 any algebraic development in Isabelle.  Currently covers group theory
   334 (up to Sylow's theorem) and ring theory (Universal Property of
   335 Univariate Polynomials).  Contributions welcome;
   336 
   337 * GroupTheory: deleted, since its material has been moved to Algebra;
   338 
   339 * Complex: new directory of the complex numbers with numeric constants, 
   340 nonstandard complex numbers, and some complex analysis, standard and 
   341 nonstandard (Jacques Fleuriot);
   342 
   343 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   344 
   345 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques 
   346 Fleuriot);
   347 
   348 * Real/HahnBanach: updated and adapted to locales;
   349 
   350 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   351 Gray and Kramer);
   352 
   353 * UNITY: added the Meier-Sanders theory of progress sets;
   354 
   355 * MicroJava: bytecode verifier and lightweight bytecode verifier
   356 as abstract algorithms, instantiated to the JVM;
   357 
   358 * Bali: Java source language formalization. Type system, operational
   359 semantics, axiomatic semantics. Supported language features:
   360 classes, interfaces, objects,virtual methods, static methods,
   361 static/instance fields, arrays, access modifiers, definite
   362 assignment, exceptions.
   363 
   364 
   365 *** ZF ***
   366 
   367 * ZF/Constructible: consistency proof for AC (Gödel's constructible
   368 universe, etc.);
   369 
   370 * Main ZF: virtually all theories converted to new-style format;
   371 
   372 
   373 *** ML ***
   374 
   375 * Pure: Tactic.prove provides sane interface for internal proofs;
   376 omits the infamous "standard" operation, so this is more appropriate
   377 than prove_goalw_cterm in many situations (e.g. in simprocs);
   378 
   379 * Pure: improved error reporting of simprocs;
   380 
   381 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   382 up simprocs;
   383 
   384 
   385 *** Document preparation ***
   386 
   387 * uses \par instead of \\ for line breaks in theory text. This may
   388 shift some page breaks in large documents. To get the old behaviour
   389 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   390 
   391 * minimized dependencies of isabelle.sty and isabellesym.sty on 
   392 other packages
   393 
   394 * \<euro> now needs package babel/greek instead of marvosym (which
   395 broke \Rightarrow)
   396 
   397 * normal size for \<zero>...\<nine> (uses \mathbf instead of 
   398 textcomp package)
   399 
   400 
   401 
   402 New in Isabelle2002 (March 2002)
   403 --------------------------------
   404 
   405 *** Document preparation ***
   406 
   407 * greatly simplified document preparation setup, including more
   408 graceful interpretation of isatool usedir -i/-d/-D options, and more
   409 instructive isatool mkdir; users should basically be able to get
   410 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   411 users may run a separate document processing stage manually like this:
   412 "isatool usedir -D output HOL Test && isatool document Test/output";
   413 
   414 * theory dependency graph may now be incorporated into documents;
   415 isatool usedir -g true will produce session_graph.eps/.pdf for use
   416 with \includegraphics of LaTeX;
   417 
   418 * proper spacing of consecutive markup elements, especially text
   419 blocks after section headings;
   420 
   421 * support bold style (for single symbols only), input syntax is like
   422 this: "\<^bold>\<alpha>" or "\<^bold>A";
   423 
   424 * \<bullet> is now output as bold \cdot by default, which looks much
   425 better in printed text;
   426 
   427 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   428 note that these symbols are currently unavailable in Proof General /
   429 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   430 
   431 * isatool latex no longer depends on changed TEXINPUTS, instead
   432 isatool document copies the Isabelle style files to the target
   433 location;
   434 
   435 
   436 *** Isar ***
   437 
   438 * Pure/Provers: improved proof by cases and induction;
   439   - 'case' command admits impromptu naming of parameters (such as
   440     "case (Suc n)");
   441   - 'induct' method divinates rule instantiation from the inductive
   442     claim; no longer requires excessive ?P bindings for proper
   443     instantiation of cases;
   444   - 'induct' method properly enumerates all possibilities of set/type
   445     rules; as a consequence facts may be also passed through *type*
   446     rules without further ado;
   447   - 'induct' method now derives symbolic cases from the *rulified*
   448     rule (before it used to rulify cases stemming from the internal
   449     atomized version); this means that the context of a non-atomic
   450     statement becomes is included in the hypothesis, avoiding the
   451     slightly cumbersome show "PROP ?case" form;
   452   - 'induct' may now use elim-style induction rules without chaining
   453     facts, using ``missing'' premises from the goal state; this allows
   454     rules stemming from inductive sets to be applied in unstructured
   455     scripts, while still benefitting from proper handling of non-atomic
   456     statements; NB: major inductive premises need to be put first, all
   457     the rest of the goal is passed through the induction;
   458   - 'induct' proper support for mutual induction involving non-atomic
   459     rule statements (uses the new concept of simultaneous goals, see
   460     below);
   461   - append all possible rule selections, but only use the first
   462     success (no backtracking);
   463   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   464   - undeclared rule case names default to numbers 1, 2, 3, ...;
   465   - added 'print_induct_rules' (covered by help item in recent Proof
   466     General versions);
   467   - moved induct/cases attributes to Pure, methods to Provers;
   468   - generic method setup instantiated for FOL and HOL;
   469 
   470 * Pure: support multiple simultaneous goal statements, for example
   471 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   472 meta-level mechanism, this acts as if several individual goals had
   473 been stated separately; in particular common proof methods need to be
   474 repeated in order to cover all claims; note that a single elimination
   475 step is *not* sufficient to establish the two conjunctions, so this
   476 fails:
   477 
   478   assume "A & B" then have A and B ..   (*".." fails*)
   479 
   480 better use "obtain" in situations as above; alternative refer to
   481 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   482 
   483 * Pure: proper integration with ``locales''; unlike the original
   484 version by Florian Kammüller, Isar locales package high-level proof
   485 contexts rather than raw logical ones (e.g. we admit to include
   486 attributes everywhere); operations on locales include merge and
   487 rename; support for implicit arguments (``structures''); simultaneous
   488 type-inference over imports and text; see also HOL/ex/Locales.thy for
   489 some examples;
   490 
   491 * Pure: the following commands have been ``localized'', supporting a
   492 target locale specification "(in name)": 'lemma', 'theorem',
   493 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   494 stored both within the locale and at the theory level (exported and
   495 qualified by the locale name);
   496 
   497 * Pure: theory goals may now be specified in ``long'' form, with
   498 ad-hoc contexts consisting of arbitrary locale elements. for example
   499 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   500 definitions may be given, too); the result is a meta-level rule with
   501 the context elements being discharged in the obvious way;
   502 
   503 * Pure: new proof command 'using' allows to augment currently used
   504 facts after a goal statement ('using' is syntactically analogous to
   505 'apply', but acts on the goal's facts only); this allows chained facts
   506 to be separated into parts given before and after a claim, as in
   507 ``from a and b have C using d and e <proof>'';
   508 
   509 * Pure: renamed "antecedent" case to "rule_context";
   510 
   511 * Pure: new 'judgment' command records explicit information about the
   512 object-logic embedding (used by several tools internally); no longer
   513 use hard-wired "Trueprop";
   514 
   515 * Pure: added 'corollary' command;
   516 
   517 * Pure: fixed 'token_translation' command;
   518 
   519 * Pure: removed obsolete 'exported' attribute;
   520 
   521 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   522 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   523 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   524 
   525 * Pure: method 'atomize' presents local goal premises as object-level
   526 statements (atomic meta-level propositions); setup controlled via
   527 rewrite rules declarations of 'atomize' attribute; example
   528 application: 'induct' method with proper rule statements in improper
   529 proof *scripts*;
   530 
   531 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   532 now consider the syntactic context of assumptions, giving a better
   533 chance to get type-inference of the arguments right (this is
   534 especially important for locales);
   535 
   536 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   537 mode;
   538 
   539 * Pure/obtain: the formal conclusion "thesis", being marked as
   540 ``internal'', may no longer be reference directly in the text;
   541 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   542 situations;
   543 
   544 * Pure: generic 'sym' attribute which declares a rule both as pure
   545 'elim?' and for the 'symmetric' operation;
   546 
   547 * Pure: marginal comments ``--'' may now occur just anywhere in the
   548 text; the fixed correlation with particular command syntax has been
   549 discontinued;
   550 
   551 * Pure: new method 'rules' is particularly well-suited for proof
   552 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   553 but often produces more compact proof terms with less detours;
   554 
   555 * Pure/Provers/classical: simplified integration with pure rule
   556 attributes and methods; the classical "intro?/elim?/dest?"
   557 declarations coincide with the pure ones; the "rule" method no longer
   558 includes classically swapped intros; "intro" and "elim" methods no
   559 longer pick rules from the context; also got rid of ML declarations
   560 AddXIs/AddXEs/AddXDs; all of this has some potential for
   561 INCOMPATIBILITY;
   562 
   563 * Provers/classical: attribute 'swapped' produces classical inversions
   564 of introduction rules;
   565 
   566 * Provers/simplifier: 'simplified' attribute may refer to explicit
   567 rules instead of full simplifier context; 'iff' attribute handles
   568 conditional rules;
   569 
   570 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   571 
   572 * HOL: 'recdef' now fails on unfinished automated proofs, use
   573 "(permissive)" option to recover old behavior;
   574 
   575 * HOL: 'inductive' no longer features separate (collective) attributes
   576 for 'intros' (was found too confusing);
   577 
   578 * HOL: properly declared induction rules less_induct and
   579 wf_induct_rule;
   580 
   581 
   582 *** HOL ***
   583 
   584 * HOL: moved over to sane numeral syntax; the new policy is as
   585 follows:
   586 
   587   - 0 and 1 are polymorphic constants, which are defined on any
   588   numeric type (nat, int, real etc.);
   589 
   590   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   591   binary representation internally;
   592 
   593   - type nat has special constructor Suc, and generally prefers Suc 0
   594   over 1::nat and Suc (Suc 0) over 2::nat;
   595 
   596 This change may cause significant problems of INCOMPATIBILITY; here
   597 are some hints on converting existing sources:
   598 
   599   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   600   entities, so expressions involving "-" (unary or binary minus) need
   601   to be spaced properly;
   602 
   603   - existing occurrences of "1" may need to be constraint "1::nat" or
   604   even replaced by Suc 0; similar for old "2";
   605 
   606   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   607 
   608   - remove all special provisions on numerals in proofs;
   609 
   610 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   611 representation (depends on bin_arith_simps in the default context);
   612 
   613 * HOL: symbolic syntax for x^2 (numeral 2);
   614 
   615 * HOL: the class of all HOL types is now called "type" rather than
   616 "term"; INCOMPATIBILITY, need to adapt references to this type class
   617 in axclass/classes, instance/arities, and (usually rare) occurrences
   618 in typings (of consts etc.); internally the class is called
   619 "HOL.type", ML programs should refer to HOLogic.typeS;
   620 
   621 * HOL/record package improvements:
   622   - new derived operations "fields" to build a partial record section,
   623     "extend" to promote a fixed record to a record scheme, and
   624     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   625     declared as simp by default;
   626   - shared operations ("more", "fields", etc.) now need to be always
   627     qualified) --- potential INCOMPATIBILITY;
   628   - removed "make_scheme" operations (use "make" with "extend") --
   629     INCOMPATIBILITY;
   630   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   631   - provides cases/induct rules for use with corresponding Isar
   632     methods (for concrete records, record schemes, concrete more
   633     parts, and schematic more parts -- in that order);
   634   - internal definitions directly based on a light-weight abstract
   635     theory of product types over typedef rather than datatype;
   636 
   637 * HOL: generic code generator for generating executable ML code from
   638 specifications; specific support for HOL constructs such as inductive
   639 datatypes and sets, as well as recursive functions; can be invoked
   640 via 'generate_code' theory section;
   641 
   642 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
   643 
   644 * HOL: consolidated and renamed several theories.  In particular:
   645 	Ord.thy has been absorbed into HOL.thy
   646 	String.thy has been absorbed into List.thy
   647  
   648 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
   649 (beware of argument permutation!);
   650 
   651 * HOL: linorder_less_split superseded by linorder_cases;
   652 
   653 * HOL/List: "nodups" renamed to "distinct";
   654 
   655 * HOL: added "The" definite description operator; move Hilbert's "Eps"
   656 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
   657   - Ex_def has changed, now need to use some_eq_ex
   658 
   659 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
   660 in this (rare) case use:
   661 
   662   delSWrapper "split_all_tac"
   663   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
   664 
   665 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
   666 MAY FAIL;
   667 
   668 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
   669 Isabelle's type classes, ^ on functions and relations has too general
   670 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
   671 necessary to attach explicit type constraints;
   672 
   673 * HOL/Relation: the prefix name of the infix "O" has been changed from
   674 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
   675 renamed accordingly (eg "compI" -> "rel_compI").
   676 
   677 * HOL: syntax translations now work properly with numerals and records
   678 expressions;
   679 
   680 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
   681 of "lam" -- INCOMPATIBILITY;
   682 
   683 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
   684 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
   685 renamed "Product_Type.unit";
   686 
   687 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
   688 
   689 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
   690 the "cases" method);
   691 
   692 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
   693 Florian Kammüller);
   694 
   695 * HOL/IMP: updated and converted to new-style theory format; several
   696 parts turned into readable document, with proper Isar proof texts and
   697 some explanations (by Gerwin Klein);
   698 
   699 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
   700 
   701 * HOL-Hyperreal is now a logic image;
   702 
   703 
   704 *** HOLCF ***
   705 
   706 * Isar: consts/constdefs supports mixfix syntax for continuous
   707 operations;
   708 
   709 * Isar: domain package adapted to new-style theory format, e.g. see
   710 HOLCF/ex/Dnat.thy;
   711 
   712 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
   713 potential INCOMPATIBILITY; now use plain induct_tac instead of former
   714 lift.induct_tac, always use UU instead of Undef;
   715 
   716 * HOLCF/IMP: updated and converted to new-style theory;
   717 
   718 
   719 *** ZF ***
   720 
   721 * Isar: proper integration of logic-specific tools and packages,
   722 including theory commands '(co)inductive', '(co)datatype',
   723 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
   724 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
   725 
   726 * theory Main no longer includes AC; for the Axiom of Choice, base
   727 your theory on Main_ZFC;
   728 
   729 * the integer library now covers quotients and remainders, with many
   730 laws relating division to addition, multiplication, etc.;
   731 
   732 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
   733 typeless version of the formalism;
   734 
   735 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
   736 format;
   737 
   738 * ZF/Induct: new directory for examples of inductive definitions,
   739 including theory Multiset for multiset orderings; converted to
   740 new-style theory format;
   741 
   742 * ZF: many new theorems about lists, ordinals, etc.;
   743 
   744 
   745 *** General ***
   746 
   747 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
   748 variable proof controls level of detail: 0 = no proofs (only oracle
   749 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
   750 also ref manual for further ML interfaces;
   751 
   752 * Pure/axclass: removed obsolete ML interface
   753 goal_subclass/goal_arity;
   754 
   755 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
   756 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
   757 separate tokens, so expressions involving minus need to be spaced
   758 properly;
   759 
   760 * Pure/syntax: support non-oriented infixes, using keyword "infix"
   761 rather than "infixl" or "infixr";
   762 
   763 * Pure/syntax: concrete syntax for dummy type variables admits genuine
   764 sort constraint specifications in type inference; e.g. "x::_::foo"
   765 ensures that the type of "x" is of sort "foo" (but not necessarily a
   766 type variable);
   767 
   768 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
   769 control output of nested => (types); the default behavior is
   770 "type_brackets";
   771 
   772 * Pure/syntax: builtin parse translation for "_constify" turns valued
   773 tokens into AST constants;
   774 
   775 * Pure/syntax: prefer later declarations of translations and print
   776 translation functions; potential INCOMPATIBILITY: need to reverse
   777 multiple declarations for same syntax element constant;
   778 
   779 * Pure/show_hyps reset by default (in accordance to existing Isar
   780 practice);
   781 
   782 * Provers/classical: renamed addaltern to addafter, addSaltern to
   783 addSafter;
   784 
   785 * Provers/clasimp: ``iff'' declarations now handle conditional rules
   786 as well;
   787 
   788 * system: tested support for MacOS X; should be able to get Isabelle +
   789 Proof General to work in a plain Terminal after installing Poly/ML
   790 (e.g. from the Isabelle distribution area) and GNU bash alone
   791 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
   792 support requires further installations, e.g. from
   793 http://fink.sourceforge.net/);
   794 
   795 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
   796 
   797 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
   798 of 40 MB), cf. ML_OPTIONS;
   799 
   800 * system: Proof General keywords specification is now part of the
   801 Isabelle distribution (see etc/isar-keywords.el);
   802 
   803 * system: support for persistent Proof General sessions (refrain from
   804 outdating all loaded theories on startup); user may create writable
   805 logic images like this: ``isabelle -q HOL Test'';
   806 
   807 * system: smart selection of Isabelle process versus Isabelle
   808 interface, accommodates case-insensitive file systems (e.g. HFS+); may
   809 run both "isabelle" and "Isabelle" even if file names are badly
   810 damaged (executable inspects the case of the first letter of its own
   811 name); added separate "isabelle-process" and "isabelle-interface";
   812 
   813 * system: refrain from any attempt at filtering input streams; no
   814 longer support ``8bit'' encoding of old isabelle font, instead proper
   815 iso-latin characters may now be used; the related isatools
   816 "symbolinput" and "nonascii" have disappeared as well;
   817 
   818 * system: removed old "xterm" interface (the print modes "xterm" and
   819 "xterm_color" are still available for direct use in a suitable
   820 terminal);
   821 
   822 
   823 
   824 New in Isabelle99-2 (February 2001)
   825 -----------------------------------
   826 
   827 *** Overview of INCOMPATIBILITIES ***
   828 
   829 * HOL: please note that theories in the Library and elsewhere often use the
   830 new-style (Isar) format; to refer to their theorems in an ML script you must
   831 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
   832 
   833 * HOL: inductive package no longer splits induction rule aggressively,
   834 but only as far as specified by the introductions given; the old
   835 format may be recovered via ML function complete_split_rule or attribute
   836 'split_rule (complete)';
   837 
   838 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
   839 gfp_Tarski to gfp_unfold;
   840 
   841 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
   842 
   843 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
   844 relation); infix "^^" has been renamed "``"; infix "``" has been
   845 renamed "`"; "univalent" has been renamed "single_valued";
   846 
   847 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
   848 operation;
   849 
   850 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
   851 
   852 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
   853 
   854 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
   855 consequence, it is no longer monotonic wrt. the local goal context
   856 (which is now passed through the inductive cases);
   857 
   858 * Document preparation: renamed standard symbols \<ll> to \<lless> and
   859 \<gg> to \<ggreater>;
   860 
   861 
   862 *** Document preparation ***
   863 
   864 * \isabellestyle{NAME} selects version of Isabelle output (currently
   865 available: are "it" for near math-mode best-style output, "sl" for
   866 slanted text style, and "tt" for plain type-writer; if no
   867 \isabellestyle command is given, output is according to slanted
   868 type-writer);
   869 
   870 * support sub/super scripts (for single symbols only), input syntax is
   871 like this: "A\<^sup>*" or "A\<^sup>\<star>";
   872 
   873 * some more standard symbols; see Appendix A of the system manual for
   874 the complete list of symbols defined in isabellesym.sty;
   875 
   876 * improved isabelle style files; more abstract symbol implementation
   877 (should now use \isamath{...} and \isatext{...} in custom symbol
   878 definitions);
   879 
   880 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
   881 state; Note that presentation of goal states does not conform to
   882 actual human-readable proof documents.  Please do not include goal
   883 states into document output unless you really know what you are doing!
   884 
   885 * proper indentation of antiquoted output with proportional LaTeX
   886 fonts;
   887 
   888 * no_document ML operator temporarily disables LaTeX document
   889 generation;
   890 
   891 * isatool unsymbolize tunes sources for plain ASCII communication;
   892 
   893 
   894 *** Isar ***
   895 
   896 * Pure: Isar now suffers initial goal statements to contain unbound
   897 schematic variables (this does not conform to actual readable proof
   898 documents, due to unpredictable outcome and non-compositional proof
   899 checking); users who know what they are doing may use schematic goals
   900 for Prolog-style synthesis of proven results;
   901 
   902 * Pure: assumption method (an implicit finishing) now handles actual
   903 rules as well;
   904 
   905 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
   906 initial goal, declare "that" only as Pure intro (only for single
   907 steps); the "that" rule assumption may now be involved in implicit
   908 finishing, thus ".." becomes a feasible for trivial obtains;
   909 
   910 * Pure: default proof step now includes 'intro_classes'; thus trivial
   911 instance proofs may be performed by "..";
   912 
   913 * Pure: ?thesis / ?this / "..." now work for pure meta-level
   914 statements as well;
   915 
   916 * Pure: more robust selection of calculational rules;
   917 
   918 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
   919 rule (as well as the assumption rule);
   920 
   921 * Pure: 'thm_deps' command visualizes dependencies of theorems and
   922 lemmas, using the graph browser tool;
   923 
   924 * Pure: predict failure of "show" in interactive mode;
   925 
   926 * Pure: 'thms_containing' now takes actual terms as arguments;
   927 
   928 * HOL: improved method 'induct' --- now handles non-atomic goals
   929 (potential INCOMPATIBILITY); tuned error handling;
   930 
   931 * HOL: cases and induct rules now provide explicit hints about the
   932 number of facts to be consumed (0 for "type" and 1 for "set" rules);
   933 any remaining facts are inserted into the goal verbatim;
   934 
   935 * HOL: local contexts (aka cases) may now contain term bindings as
   936 well; the 'cases' and 'induct' methods new provide a ?case binding for
   937 the result to be shown in each case;
   938 
   939 * HOL: added 'recdef_tc' command;
   940 
   941 * isatool convert assists in eliminating legacy ML scripts;
   942 
   943 
   944 *** HOL ***
   945 
   946 * HOL/Library: a collection of generic theories to be used together
   947 with main HOL; the theory loader path already includes this directory
   948 by default; the following existing theories have been moved here:
   949 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
   950 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
   951 
   952 * HOL/Unix: "Some aspects of Unix file-system security", a typical
   953 modelling and verification task performed in Isabelle/HOL +
   954 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
   955 
   956 * HOL/Algebra: special summation operator SUM no longer exists, it has
   957 been replaced by setsum; infix 'assoc' now has priority 50 (like
   958 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
   959 'domain', this makes the theory consistent with mathematical
   960 literature;
   961 
   962 * HOL basics: added overloaded operations "inverse" and "divide"
   963 (infix "/"), syntax for generic "abs" operation, generic summation
   964 operator \<Sum>;
   965 
   966 * HOL/typedef: simplified package, provide more useful rules (see also
   967 HOL/subset.thy);
   968 
   969 * HOL/datatype: induction rule for arbitrarily branching datatypes is
   970 now expressed as a proper nested rule (old-style tactic scripts may
   971 require atomize_strip_tac to cope with non-atomic premises);
   972 
   973 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
   974 to "split_conv" (old name still available for compatibility);
   975 
   976 * HOL: improved concrete syntax for strings (e.g. allows translation
   977 rules with string literals);
   978 
   979 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
   980  and Fleuriot's mechanization of analysis, including the transcendental
   981  functions for the reals;
   982 
   983 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
   984 
   985 
   986 *** CTT ***
   987 
   988 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
   989 "lam" is displayed as TWO lambda-symbols
   990 
   991 * CTT: theory Main now available, containing everything (that is, Bool
   992 and Arith);
   993 
   994 
   995 *** General ***
   996 
   997 * Pure: the Simplifier has been implemented properly as a derived rule
   998 outside of the actual kernel (at last!); the overall performance
   999 penalty in practical applications is about 50%, while reliability of
  1000 the Isabelle inference kernel has been greatly improved;
  1001 
  1002 * print modes "brackets" and "no_brackets" control output of nested =>
  1003 (types) and ==> (props); the default behaviour is "brackets";
  1004 
  1005 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1006 as assumptions as well;
  1007 
  1008 * system: support Poly/ML 4.0;
  1009 
  1010 * system: isatool install handles KDE version 1 or 2;
  1011 
  1012 
  1013 
  1014 New in Isabelle99-1 (October 2000)
  1015 ----------------------------------
  1016 
  1017 *** Overview of INCOMPATIBILITIES ***
  1018 
  1019 * HOL: simplification of natural numbers is much changed; to partly
  1020 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1021 issue the following ML commands:
  1022 
  1023   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1024   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1025 
  1026 * HOL: simplification no longer dives into case-expressions; this is
  1027 controlled by "t.weak_case_cong" for each datatype t;
  1028 
  1029 * HOL: nat_less_induct renamed to less_induct;
  1030 
  1031 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1032 fixsome to patch .thy and .ML sources automatically;
  1033 
  1034   select_equality  -> some_equality
  1035   select_eq_Ex     -> some_eq_ex
  1036   selectI2EX       -> someI2_ex
  1037   selectI2         -> someI2
  1038   selectI          -> someI
  1039   select1_equality -> some1_equality
  1040   Eps_sym_eq       -> some_sym_eq_trivial
  1041   Eps_eq           -> some_eq_trivial
  1042 
  1043 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1044 
  1045 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1046 instead);
  1047 
  1048 * HOL: the recursion equations generated by 'recdef' are now called
  1049 f.simps instead of f.rules;
  1050 
  1051 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1052 
  1053 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1054 sometimes be needed;
  1055 
  1056 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1057 
  1058 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1059 
  1060 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1061 product is now "<*>" instead of "Times"; the lexicographic product is
  1062 now "<*lex*>" instead of "**";
  1063 
  1064 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1065 of main HOL, but was unused); better use HOL's datatype package;
  1066 
  1067 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1068 the old syntax may be recovered as follows:
  1069 
  1070   syntax (symbols)
  1071     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1072       (infixl "\\<oplus>" 100)
  1073 
  1074 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1075 
  1076 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1077 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1078 internally;
  1079 
  1080 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1081 changed from A/r to A//r;
  1082 
  1083 * ZF: new treatment of arithmetic (nat & int) may break some old
  1084 proofs;
  1085 
  1086 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1087 rulify -> rule_format, elimify -> elim_format, ...);
  1088 
  1089 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1090 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1091 should have to change intro!! to intro? only); replaced "delrule" by
  1092 "rule del";
  1093 
  1094 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1095 
  1096 * Provers: strengthened force_tac by using new first_best_tac;
  1097 
  1098 * LaTeX document preparation: several changes of isabelle.sty (see
  1099 lib/texinputs);
  1100 
  1101 
  1102 *** Document preparation ***
  1103 
  1104 * formal comments (text blocks etc.) in new-style theories may now
  1105 contain antiquotations of thm/prop/term/typ/text to be presented
  1106 according to latex print mode; concrete syntax is like this:
  1107 @{term[show_types] "f(x) = a + x"};
  1108 
  1109 * isatool mkdir provides easy setup of Isabelle session directories,
  1110 including proper document sources;
  1111 
  1112 * generated LaTeX sources are now deleted after successful run
  1113 (isatool document -c); may retain a copy somewhere else via -D option
  1114 of isatool usedir;
  1115 
  1116 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1117 style files, achieving self-contained LaTeX sources and simplifying
  1118 LaTeX debugging;
  1119 
  1120 * old-style theories now produce (crude) LaTeX output as well;
  1121 
  1122 * browser info session directories are now self-contained (may be put
  1123 on WWW server seperately); improved graphs of nested sessions; removed
  1124 graph for 'all sessions';
  1125 
  1126 * several improvements in isabelle style files; \isabellestyle{it}
  1127 produces fake math mode output; \isamarkupheader is now \section by
  1128 default; see lib/texinputs/isabelle.sty etc.;
  1129 
  1130 
  1131 *** Isar ***
  1132 
  1133 * Isar/Pure: local results and corresponding term bindings are now
  1134 subject to Hindley-Milner polymorphism (similar to ML); this
  1135 accommodates incremental type-inference very nicely;
  1136 
  1137 * Isar/Pure: new derived language element 'obtain' supports
  1138 generalized existence reasoning;
  1139 
  1140 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1141 support accumulation of results, without applying any rules yet;
  1142 useful to collect intermediate results without explicit name
  1143 references, and for use with transitivity rules with more than 2
  1144 premises;
  1145 
  1146 * Isar/Pure: scalable support for case-analysis type proofs: new
  1147 'case' language element refers to local contexts symbolically, as
  1148 produced by certain proof methods; internally, case names are attached
  1149 to theorems as "tags";
  1150 
  1151 * Isar/Pure: theory command 'hide' removes declarations from
  1152 class/type/const name spaces;
  1153 
  1154 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1155 indicate potential overloading;
  1156 
  1157 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1158 
  1159 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1160 "{a,b,c}" instead of {a,b,c};
  1161 
  1162 * Isar/Pure now provides its own version of intro/elim/dest
  1163 attributes; useful for building new logics, but beware of confusion
  1164 with the version in Provers/classical;
  1165 
  1166 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1167 case name 'antecedent';
  1168 
  1169 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1170 to the current context is now done automatically);
  1171 
  1172 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1173 for definining proof methods in ML;
  1174 
  1175 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1176 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1177 most cases, one should have to change intro!! to intro? only);
  1178 replaced "delrule" by "rule del";
  1179 
  1180 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1181 'symmetric' attribute (the latter supercedes [RS sym]);
  1182 
  1183 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1184 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1185 well (including splits);
  1186 
  1187 * Isar/Provers: Simplifier and Classical methods now support all kind
  1188 of modifiers used in the past, including 'cong', 'iff', etc.
  1189 
  1190 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1191 of Simplifier and Classical reasoner);
  1192 
  1193 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1194 now support named cases; major packages (inductive, datatype, primrec,
  1195 recdef) support case names and properly name parameters;
  1196 
  1197 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1198 monotonicity conditions are extracted to be proven at end of
  1199 calculations;
  1200 
  1201 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1202 method anyway;
  1203 
  1204 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1205 split_if split_if_asm; datatype package provides theorems foo.splits =
  1206 foo.split foo.split_asm for each datatype;
  1207 
  1208 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1209 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1210 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1211 use "(cases (simplified))" method in proper proof texts);
  1212 
  1213 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1214 
  1215 * Isar: names of theorems etc. may be natural numbers as well;
  1216 
  1217 * Isar: 'pr' command: optional arguments for goals_limit and
  1218 ProofContext.prems_limit; no longer prints theory contexts, but only
  1219 proof states;
  1220 
  1221 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1222 additional print modes to be specified; e.g. "pr(latex)" will print
  1223 proof state according to the Isabelle LaTeX style;
  1224 
  1225 * Isar: improved support for emulating tactic scripts, including proof
  1226 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1227 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1228 (for HOL datatypes);
  1229 
  1230 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1231 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1232 'proof method scripts' have to be in depth-first order;
  1233 
  1234 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1235 
  1236 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1237 should instead use individual commands for printing items
  1238 (print_commands, print_methods etc.);
  1239 
  1240 * Isar: added 'nothing' --- the empty list of theorems;
  1241 
  1242 
  1243 *** HOL ***
  1244 
  1245 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1246 corresponding virtual machine and a specification of its bytecode
  1247 verifier and a lightweight bytecode verifier, including proofs of
  1248 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1249 Cornelia Pusch (see also the homepage of project Bali at
  1250 http://isabelle.in.tum.de/Bali/);
  1251 
  1252 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1253 Clemens Ballarin;
  1254 
  1255 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1256 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1257 Rasmussen;
  1258 
  1259 * HOL/Lattice: fundamental concepts of lattice theory and order
  1260 structures, including duals, properties of bounds versus algebraic
  1261 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1262 Theorem for complete lattices etc.; may also serve as a demonstration
  1263 for abstract algebraic reasoning using axiomatic type classes, and
  1264 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1265 
  1266 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1267 von Oheimb;
  1268 
  1269 * HOL/IMPP: extension of IMP with local variables and mutually
  1270 recursive procedures, by David von Oheimb;
  1271 
  1272 * HOL/Lambda: converted into new-style theory and document;
  1273 
  1274 * HOL/ex/Multiquote: example of multiple nested quotations and
  1275 anti-quotations -- basically a generalized version of de-Bruijn
  1276 representation; very useful in avoiding lifting of operations;
  1277 
  1278 * HOL/record: added general record equality rule to simpset; fixed
  1279 select-update simplification procedure to handle extended records as
  1280 well; admit "r" as field name;
  1281 
  1282 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1283 other numeric types and also as the identity of groups, rings, etc.;
  1284 
  1285 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1286 Types nat and int belong to this axclass;
  1287 
  1288 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1289    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1290    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1291   two terms #m*u and #n*u are replaced by #(m+n)*u
  1292     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1293   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1294     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1295 
  1296 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1297 powerful prover for predicate logic but knows nothing of clasets; see
  1298 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1299 
  1300 * HOL: new version of "case_tac" subsumes both boolean case split and
  1301 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1302 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1303 
  1304 * HOL: simplification no longer dives into case-expressions: only the
  1305 selector expression is simplified, but not the remaining arms; to
  1306 enable full simplification of case-expressions for datatype t, you may
  1307 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1308 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1309 
  1310 * HOL/recdef: the recursion equations generated by 'recdef' for
  1311 function 'f' are now called f.simps instead of f.rules; if all
  1312 termination conditions are proved automatically, these simplification
  1313 rules are added to the simpset, as in primrec; rules may be named
  1314 individually as well, resulting in a separate list of theorems for
  1315 each equation;
  1316 
  1317 * HOL/While is a new theory that provides a while-combinator. It
  1318 permits the definition of tail-recursive functions without the
  1319 provision of a termination measure. The latter is necessary once the
  1320 invariant proof rule for while is applied.
  1321 
  1322 * HOL: new (overloaded) notation for the set of elements below/above
  1323 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1324 
  1325 * HOL: theorems impI, allI, ballI bound as "strip";
  1326 
  1327 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1328 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1329 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1330 
  1331 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1332 
  1333 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1334 main HOL, but was unused);
  1335 
  1336 * HOL: fewer consts declared as global (e.g. have to refer to
  1337 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1338 
  1339 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1340 in case of overlap with user translations (e.g. judgements over
  1341 tuples); (note that the underlying logical represenation is still
  1342 bogus);
  1343 
  1344 
  1345 *** ZF ***
  1346 
  1347 * ZF: simplification automatically cancels common terms in arithmetic
  1348 expressions over nat and int;
  1349 
  1350 * ZF: new treatment of nat to minimize type-checking: all operators
  1351 coerce their operands to a natural number using the function natify,
  1352 making the algebraic laws unconditional;
  1353 
  1354 * ZF: as above, for int: operators coerce their operands to an integer
  1355 using the function intify;
  1356 
  1357 * ZF: the integer library now contains many of the usual laws for the
  1358 orderings, including $<=, and monotonicity laws for $+ and $*;
  1359 
  1360 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1361 simplification;
  1362 
  1363 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1364 to the simplifier and classical reasoner simultaneously;
  1365 
  1366 
  1367 *** General ***
  1368 
  1369 * Provers: blast_tac now handles actual object-logic rules as
  1370 assumptions; note that auto_tac uses blast_tac internally as well;
  1371 
  1372 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1373 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1374 
  1375 * Provers: delrules now handles destruct rules as well (no longer need
  1376 explicit make_elim);
  1377 
  1378 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1379   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1380 use instead the strong form,
  1381   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1382 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1383 from destruct-rules;
  1384 
  1385 * Provers: Simplifier.easy_setup provides a fast path to basic
  1386 Simplifier setup for new object-logics;
  1387 
  1388 * Pure: AST translation rules no longer require constant head on LHS;
  1389 
  1390 * Pure: improved name spaces: ambiguous output is qualified; support
  1391 for hiding of names;
  1392 
  1393 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1394 XSYMBOL_HOME; no longer need to do manual configuration in most
  1395 situations;
  1396 
  1397 * system: compression of ML heaps images may now be controlled via -c
  1398 option of isabelle and isatool usedir (currently only observed by
  1399 Poly/ML);
  1400 
  1401 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1402 useful for remote X11);
  1403 
  1404 * system: provide TAGS file for Isabelle sources;
  1405 
  1406 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1407 order;
  1408 
  1409 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1410 timing flag supersedes proof_timing and Toplevel.trace;
  1411 
  1412 * ML: new combinators |>> and |>>> for incremental transformations
  1413 with secondary results (e.g. certain theory extensions):
  1414 
  1415 * ML: PureThy.add_defs gets additional argument to indicate potential
  1416 overloading (usually false);
  1417 
  1418 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1419 results;
  1420 
  1421 
  1422 
  1423 New in Isabelle99 (October 1999)
  1424 --------------------------------
  1425 
  1426 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1427 
  1428 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1429 are no longer simplified.  (This allows the simplifier to unfold recursive
  1430 functional programs.)  To restore the old behaviour, declare
  1431 
  1432     Delcongs [if_weak_cong];
  1433 
  1434 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1435 complement;
  1436 
  1437 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1438 
  1439 * HOL/datatype: mutual_induct_tac no longer exists --
  1440   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1441 
  1442 * HOL/typedef: fixed type inference for representing set; type
  1443 arguments now have to occur explicitly on the rhs as type constraints;
  1444 
  1445 * ZF: The con_defs part of an inductive definition may no longer refer
  1446 to constants declared in the same theory;
  1447 
  1448 * HOL, ZF: the function mk_cases, generated by the inductive
  1449 definition package, has lost an argument.  To simplify its result, it
  1450 uses the default simpset instead of a supplied list of theorems.
  1451 
  1452 * HOL/List: the constructors of type list are now Nil and Cons;
  1453 
  1454 * Simplifier: the type of the infix ML functions
  1455         setSSolver addSSolver setSolver addSolver
  1456 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1457 for packaging solvers. A solver is created via
  1458         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1459 where the string argument is only a comment.
  1460 
  1461 
  1462 *** Proof tools ***
  1463 
  1464 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1465 decision procedure for linear arithmetic. Currently it is used for
  1466 types `nat', `int', and `real' in HOL (see below); it can, should and
  1467 will be instantiated for other types and logics as well.
  1468 
  1469 * The simplifier now accepts rewrite rules with flexible heads, eg
  1470      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1471   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1472   matching.
  1473 
  1474 
  1475 *** General ***
  1476 
  1477 * New Isabelle/Isar subsystem provides an alternative to traditional
  1478 tactical theorem proving; together with the ProofGeneral/isar user
  1479 interface it offers an interactive environment for developing human
  1480 readable proof documents (Isar == Intelligible semi-automated
  1481 reasoning); for further information see isatool doc isar-ref,
  1482 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1483 
  1484 * improved and simplified presentation of theories: better HTML markup
  1485 (including colors), graph views in several sizes; isatool usedir now
  1486 provides a proper interface for user theories (via -P option); actual
  1487 document preparation based on (PDF)LaTeX is available as well (for
  1488 new-style theories only); see isatool doc system for more information;
  1489 
  1490 * native support for Proof General, both for classic Isabelle and
  1491 Isabelle/Isar;
  1492 
  1493 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1494 using the graph browser tool;
  1495 
  1496 * Isabelle manuals now also available as PDF;
  1497 
  1498 * theory loader rewritten from scratch (may not be fully
  1499 bug-compatible); old loadpath variable has been replaced by show_path,
  1500 add_path, del_path, reset_path functions; new operations such as
  1501 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1502 isatool doc ref);
  1503 
  1504 * improved isatool install: option -k creates KDE application icon,
  1505 option -p DIR installs standalone binaries;
  1506 
  1507 * added ML_PLATFORM setting (useful for cross-platform installations);
  1508 more robust handling of platform specific ML images for SML/NJ;
  1509 
  1510 * the settings environment is now statically scoped, i.e. it is never
  1511 created again in sub-processes invoked from isabelle, isatool, or
  1512 Isabelle;
  1513 
  1514 * path element specification '~~' refers to '$ISABELLE_HOME';
  1515 
  1516 * in locales, the "assumes" and "defines" parts may be omitted if
  1517 empty;
  1518 
  1519 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1520 long arrows);
  1521 
  1522 * new print_mode "HTML";
  1523 
  1524 * new flag show_tags controls display of tags of theorems (which are
  1525 basically just comments that may be attached by some tools);
  1526 
  1527 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1528 mode and goal output format:
  1529 
  1530 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1531 244c244
  1532 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1533 ---
  1534 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1535 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1536 181c181
  1537 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1538 ---
  1539 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1540 
  1541 * function bind_thms stores lists of theorems (cf. bind_thm);
  1542 
  1543 * new shorthand tactics ftac, eatac, datac, fatac;
  1544 
  1545 * qed (and friends) now accept "" as result name; in that case the
  1546 theorem is not stored, but proper checks and presentation of the
  1547 result still apply;
  1548 
  1549 * theorem database now also indexes constants "Trueprop", "all",
  1550 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1551 
  1552 
  1553 *** HOL ***
  1554 
  1555 ** HOL arithmetic **
  1556 
  1557 * There are now decision procedures for linear arithmetic over nat and
  1558 int:
  1559 
  1560 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1561 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1562 are treated as atomic; subformulae not involving type `nat' or `int'
  1563 are ignored; quantified subformulae are ignored unless they are
  1564 positive universal or negative existential. The tactic has to be
  1565 invoked by hand and can be a little bit slow. In particular, the
  1566 running time is exponential in the number of occurrences of `min' and
  1567 `max', and `-' on `nat'.
  1568 
  1569 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1570 (negated) (in)equalities among the premises and the conclusion into
  1571 account (i.e. no compound formulae) and does not know about `min' and
  1572 `max', and `-' on `nat'. It is fast and is used automatically by the
  1573 simplifier.
  1574 
  1575 NB: At the moment, these decision procedures do not cope with mixed
  1576 nat/int formulae where the two parts interact, such as `m < n ==>
  1577 int(m) < int(n)'.
  1578 
  1579 * HOL/Numeral provides a generic theory of numerals (encoded
  1580 efficiently as bit strings); setup for types nat/int/real is in place;
  1581 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1582 int, existing theories and proof scripts may require a few additional
  1583 type constraints;
  1584 
  1585 * integer division and remainder can now be performed on constant
  1586 arguments;
  1587 
  1588 * many properties of integer multiplication, division and remainder
  1589 are now available;
  1590 
  1591 * An interface to the Stanford Validity Checker (SVC) is available through the
  1592 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1593 are proved automatically.  SVC must be installed separately, and its results
  1594 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1595 invocation of the underlying oracle).  For SVC see
  1596   http://verify.stanford.edu/SVC
  1597 
  1598 * IsaMakefile: the HOL-Real target now builds an actual image;
  1599 
  1600 
  1601 ** HOL misc **
  1602 
  1603 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1604 (in Isabelle/Isar) -- by Gertrud Bauer;
  1605 
  1606 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1607 analysis for assembly languages with subtypes;
  1608 
  1609 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1610 -- avoids syntactic ambiguities and treats state, transition, and
  1611 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1612 changed syntax and (many) tactics;
  1613 
  1614 * HOL/inductive: Now also handles more general introduction rules such
  1615   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1616   theorems are now maintained within the theory (maintained via the
  1617   "mono" attribute);
  1618 
  1619 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1620   (using function types) such as
  1621 
  1622   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1623 
  1624 * HOL/record: record_simproc (part of the default simpset) takes care
  1625 of selectors applied to updated records; record_split_tac is no longer
  1626 part of the default claset; update_defs may now be removed from the
  1627 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1628 
  1629   claset_ref () := claset() addSWrapper record_split_wrapper;
  1630   Delsimprocs [record_simproc]
  1631 
  1632 * HOL/typedef: fixed type inference for representing set; type
  1633 arguments now have to occur explicitly on the rhs as type constraints;
  1634 
  1635 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1636 names rather than an ML expression;
  1637 
  1638 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1639 supplied later.  Program schemes can be defined, such as
  1640     "While B C s = (if B s then While B C (C s) else s)"
  1641 where the well-founded relation can be chosen after B and C have been given.
  1642 
  1643 * HOL/List: the constructors of type list are now Nil and Cons;
  1644 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  1645 course, ML tools referring to List.list.op # etc. have to be adapted;
  1646 
  1647 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  1648 disabled by default; run isabelle with option -m HOL to get back to
  1649 the original Gordon/HOL-style output;
  1650 
  1651 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  1652 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  1653 
  1654 * HOL basic syntax simplified (more orthogonal): all variants of
  1655 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  1656 Eps operator is provided as well: "SOME x. P[x]";
  1657 
  1658 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  1659 
  1660 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  1661 thus available for user theories;
  1662 
  1663 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  1664 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  1665 time;
  1666 
  1667 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  1668 several times and then mp;
  1669 
  1670 
  1671 *** LK ***
  1672 
  1673 * the notation <<...>> is now available as a notation for sequences of
  1674 formulas;
  1675 
  1676 * the simplifier is now installed
  1677 
  1678 * the axiom system has been generalized (thanks to Soren Heilmann)
  1679 
  1680 * the classical reasoner now has a default rule database
  1681 
  1682 
  1683 *** ZF ***
  1684 
  1685 * new primrec section allows primitive recursive functions to be given
  1686 directly (as in HOL) over datatypes and the natural numbers;
  1687 
  1688 * new tactics induct_tac and exhaust_tac for induction (or case
  1689 analysis) over datatypes and the natural numbers;
  1690 
  1691 * the datatype declaration of type T now defines the recursor T_rec;
  1692 
  1693 * simplification automatically does freeness reasoning for datatype
  1694 constructors;
  1695 
  1696 * automatic type-inference, with AddTCs command to insert new
  1697 type-checking rules;
  1698 
  1699 * datatype introduction rules are now added as Safe Introduction rules
  1700 to the claset;
  1701 
  1702 * the syntax "if P then x else y" is now available in addition to
  1703 if(P,x,y);
  1704 
  1705 
  1706 *** Internal programming interfaces ***
  1707 
  1708 * tuned simplifier trace output; new flag debug_simp;
  1709 
  1710 * structures Vartab / Termtab (instances of TableFun) offer efficient
  1711 tables indexed by indexname_ord / term_ord (compatible with aconv);
  1712 
  1713 * AxClass.axclass_tac lost the theory argument;
  1714 
  1715 * tuned current_goals_markers semantics: begin / end goal avoids
  1716 printing empty lines;
  1717 
  1718 * removed prs and prs_fn hook, which was broken because it did not
  1719 include \n in its semantics, forcing writeln to add one
  1720 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  1721 string -> unit if you really want to output text without newline;
  1722 
  1723 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  1724 plain output, interface builders may have to enable 'isabelle_font'
  1725 mode to get Isabelle font glyphs as before;
  1726 
  1727 * refined token_translation interface; INCOMPATIBILITY: output length
  1728 now of type real instead of int;
  1729 
  1730 * theory loader actions may be traced via new ThyInfo.add_hook
  1731 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  1732 your own database of information attached to *whole* theories -- as
  1733 opposed to intra-theory data slots offered via TheoryDataFun;
  1734 
  1735 * proper handling of dangling sort hypotheses (at last!);
  1736 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  1737 extra sort hypotheses that can be witnessed from the type signature;
  1738 the force_strip_shyps flag is gone, any remaining shyps are simply
  1739 left in the theorem (with a warning issued by strip_shyps_warning);
  1740 
  1741 
  1742 
  1743 New in Isabelle98-1 (October 1998)
  1744 ----------------------------------
  1745 
  1746 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1747 
  1748 * several changes of automated proof tools;
  1749 
  1750 * HOL: major changes to the inductive and datatype packages, including
  1751 some minor incompatibilities of theory syntax;
  1752 
  1753 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  1754 called `inj_on';
  1755 
  1756 * HOL: removed duplicate thms in Arith:
  1757   less_imp_add_less  should be replaced by  trans_less_add1
  1758   le_imp_add_le      should be replaced by  trans_le_add1
  1759 
  1760 * HOL: unary minus is now overloaded (new type constraints may be
  1761 required);
  1762 
  1763 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  1764 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  1765 now taken as an integer constant.
  1766 
  1767 * Pure: ML function 'theory_of' renamed to 'theory';
  1768 
  1769 
  1770 *** Proof tools ***
  1771 
  1772 * Simplifier:
  1773   1. Asm_full_simp_tac is now more aggressive.
  1774      1. It will sometimes reorient premises if that increases their power to
  1775         simplify.
  1776      2. It does no longer proceed strictly from left to right but may also
  1777         rotate premises to achieve further simplification.
  1778      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  1779      old Asm_full_simp_tac in that it does not rotate premises.
  1780   2. The simplifier now knows a little bit about nat-arithmetic.
  1781 
  1782 * Classical reasoner: wrapper mechanism for the classical reasoner now
  1783 allows for selected deletion of wrappers, by introduction of names for
  1784 wrapper functionals.  This implies that addbefore, addSbefore,
  1785 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  1786 and that adding two tactics with the same name overwrites the first
  1787 one (emitting a warning).
  1788   type wrapper = (int -> tactic) -> (int -> tactic)
  1789   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  1790   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  1791   delWrapper, delSWrapper: claset *  string            -> claset
  1792   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  1793 
  1794 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  1795 semantics; addbefore now affects only the unsafe part of step_tac
  1796 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  1797 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  1798 by Force_tac;
  1799 
  1800 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  1801 compWrapper; added safe wrapper (and access functions for it);
  1802 
  1803 * HOL/split_all_tac is now much faster and fails if there is nothing
  1804 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  1805 and the names of the automatically generated variables have changed.
  1806 split_all_tac has moved within claset() from unsafe wrappers to safe
  1807 wrappers, which means that !!-bound variables are split much more
  1808 aggressively, and safe_tac and clarify_tac now split such variables.
  1809 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  1810 Note: the same holds for record_split_tac, which does the job of
  1811 split_all_tac for record fields.
  1812 
  1813 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  1814 permanently to the default simpset using Addsplits just like
  1815 Addsimps. They can be removed via Delsplits just like
  1816 Delsimps. Lower-case versions are also available.
  1817 
  1818 * HOL/Simplifier: The rule split_if is now part of the default
  1819 simpset. This means that the simplifier will eliminate all occurrences
  1820 of if-then-else in the conclusion of a goal. To prevent this, you can
  1821 either remove split_if completely from the default simpset by
  1822 `Delsplits [split_if]' or remove it in a specific call of the
  1823 simplifier using `... delsplits [split_if]'.  You can also add/delete
  1824 other case splitting rules to/from the default simpset: every datatype
  1825 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  1826 t is the name of the datatype).
  1827 
  1828 * Classical reasoner / Simplifier combination: new force_tac (and
  1829 derivatives Force_tac, force) combines rewriting and classical
  1830 reasoning (and whatever other tools) similarly to auto_tac, but is
  1831 aimed to solve the given subgoal completely.
  1832 
  1833 
  1834 *** General ***
  1835 
  1836 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  1837 and `goalw': the theory is no longer needed as an explicit argument -
  1838 the current theory context is used; assumptions are no longer returned
  1839 at the ML-level unless one of them starts with ==> or !!; it is
  1840 recommended to convert to these new commands using isatool fixgoal
  1841 (backup your sources first!);
  1842 
  1843 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  1844 the current theory context, and 'theory' to lookup stored theories;
  1845 
  1846 * new theory section 'locale' for declaring constants, assumptions and
  1847 definitions that have local scope;
  1848 
  1849 * new theory section 'nonterminals' for purely syntactic types;
  1850 
  1851 * new theory section 'setup' for generic ML setup functions
  1852 (e.g. package initialization);
  1853 
  1854 * the distribution now includes Isabelle icons: see
  1855 lib/logo/isabelle-{small,tiny}.xpm;
  1856 
  1857 * isatool install - install binaries with absolute references to
  1858 ISABELLE_HOME/bin;
  1859 
  1860 * isatool logo -- create instances of the Isabelle logo (as EPS);
  1861 
  1862 * print mode 'emacs' reserved for Isamode;
  1863 
  1864 * support multiple print (ast) translations per constant name;
  1865 
  1866 * theorems involving oracles are now printed with a suffixed [!];
  1867 
  1868 
  1869 *** HOL ***
  1870 
  1871 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  1872 
  1873 * HOL/inductive package reorganized and improved: now supports mutual
  1874 definitions such as
  1875 
  1876   inductive EVEN ODD
  1877     intrs
  1878       null "0 : EVEN"
  1879       oddI "n : EVEN ==> Suc n : ODD"
  1880       evenI "n : ODD ==> Suc n : EVEN"
  1881 
  1882 new theorem list "elims" contains an elimination rule for each of the
  1883 recursive sets; inductive definitions now handle disjunctive premises
  1884 correctly (also ZF);
  1885 
  1886 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  1887 "mutual_induct" no longer exists - the induction rule is always
  1888 contained in "induct";
  1889 
  1890 
  1891 * HOL/datatype package re-implemented and greatly improved: now
  1892 supports mutually recursive datatypes such as
  1893 
  1894   datatype
  1895     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  1896             | SUM ('a aexp) ('a aexp)
  1897             | DIFF ('a aexp) ('a aexp)
  1898             | NUM 'a
  1899   and
  1900     'a bexp = LESS ('a aexp) ('a aexp)
  1901             | AND ('a bexp) ('a bexp)
  1902             | OR ('a bexp) ('a bexp)
  1903 
  1904 as well as indirectly recursive datatypes such as
  1905 
  1906   datatype
  1907     ('a, 'b) term = Var 'a
  1908                   | App 'b ((('a, 'b) term) list)
  1909 
  1910 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  1911 induction on mutually / indirectly recursive datatypes.
  1912 
  1913 Primrec equations are now stored in theory and can be accessed via
  1914 <function_name>.simps.
  1915 
  1916 INCOMPATIBILITIES:
  1917 
  1918   - Theories using datatypes must now have theory Datatype as an
  1919     ancestor.
  1920   - The specific <typename>.induct_tac no longer exists - use the
  1921     generic induct_tac instead.
  1922   - natE has been renamed to nat.exhaust - use exhaust_tac
  1923     instead of res_inst_tac ... natE. Note that the variable
  1924     names in nat.exhaust differ from the names in natE, this
  1925     may cause some "fragile" proofs to fail.
  1926   - The theorems split_<typename>_case and split_<typename>_case_asm
  1927     have been renamed to <typename>.split and <typename>.split_asm.
  1928   - Since default sorts of type variables are now handled correctly,
  1929     some datatype definitions may have to be annotated with explicit
  1930     sort constraints.
  1931   - Primrec definitions no longer require function name and type
  1932     of recursive argument.
  1933 
  1934 Consider using isatool fixdatatype to adapt your theories and proof
  1935 scripts to the new package (backup your sources first!).
  1936 
  1937 
  1938 * HOL/record package: considerably improved implementation; now
  1939 includes concrete syntax for record types, terms, updates; theorems
  1940 for surjective pairing and splitting !!-bound record variables; proof
  1941 support is as follows:
  1942 
  1943   1) standard conversions (selectors or updates applied to record
  1944 constructor terms) are part of the standard simpset;
  1945 
  1946   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  1947 made part of standard simpset and claset via addIffs;
  1948 
  1949   3) a tactic for record field splitting (record_split_tac) is part of
  1950 the standard claset (addSWrapper);
  1951 
  1952 To get a better idea about these rules you may retrieve them via
  1953 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  1954 the name of your record type.
  1955 
  1956 The split tactic 3) conceptually simplifies by the following rule:
  1957 
  1958   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  1959 
  1960 Thus any record variable that is bound by meta-all will automatically
  1961 blow up into some record constructor term, consequently the
  1962 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  1963 solve record problems automatically.
  1964 
  1965 
  1966 * reorganized the main HOL image: HOL/Integ and String loaded by
  1967 default; theory Main includes everything;
  1968 
  1969 * automatic simplification of integer sums and comparisons, using cancellation;
  1970 
  1971 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  1972 
  1973 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  1974 
  1975 * many new identities for unions, intersections, set difference, etc.;
  1976 
  1977 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  1978 called split_if, split_split, split_sum_case and split_nat_case (to go
  1979 with add/delsplits);
  1980 
  1981 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  1982 (?x::unit) = (); this is made part of the default simpset, which COULD
  1983 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  1984 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  1985 unit_abs_eta_conv is added in order to counter the effect of
  1986 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  1987 %u.f();
  1988 
  1989 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  1990 makes more sense);
  1991 
  1992 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  1993   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  1994   disjointness reasoning but breaking a few old proofs.
  1995 
  1996 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  1997 to 'converse' from 'inverse' (for compatibility with ZF and some
  1998 literature);
  1999 
  2000 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2001 the well-founded relation;
  2002 
  2003 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2004     Compl A.  The "Compl" syntax remains available as input syntax for this
  2005     release ONLY.
  2006 
  2007 * HOL/Update: new theory of function updates:
  2008     f(a:=b) == %x. if x=a then b else f x
  2009 may also be iterated as in f(a:=b,c:=d,...);
  2010 
  2011 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2012 
  2013 * HOL/List:
  2014   - new function list_update written xs[i:=v] that updates the i-th
  2015     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2016   - new function `upt' written [i..j(] which generates the list
  2017     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2018     bound write [i..j], which is a shorthand for [i..j+1(].
  2019   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2020 
  2021 * HOL/Arith:
  2022   - removed 'pred' (predecessor) function;
  2023   - generalized some theorems about n-1;
  2024   - many new laws about "div" and "mod";
  2025   - new laws about greatest common divisors (see theory ex/Primes);
  2026 
  2027 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2028 instead of "inverse";
  2029 
  2030 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2031   of the multiset ordering;
  2032 
  2033 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2034   (not included by default);
  2035 
  2036 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2037 
  2038 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2039   programs, i.e. different program variables may have different types.
  2040 
  2041 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2042   [previously, this check worked only if the rewrite rule was unconditional]
  2043   Now rew can involve either definitions or equalities (either == or =).
  2044 
  2045 
  2046 *** ZF ***
  2047 
  2048 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2049   only the theorems proved on ZF.ML;
  2050 
  2051 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2052   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2053   disjointness reasoning but breaking a few old proofs.
  2054 
  2055 * ZF/Update: new theory of function updates
  2056     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2057   may also be iterated as in f(a:=b,c:=d,...);
  2058 
  2059 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2060 
  2061 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2062   [previously, this check worked only if the rewrite rule was unconditional]
  2063   Now rew can involve either definitions or equalities (either == or =).
  2064 
  2065 * case_tac provided for compatibility with HOL
  2066     (like the old excluded_middle_tac, but with subgoals swapped)
  2067 
  2068 
  2069 *** Internal programming interfaces ***
  2070 
  2071 * Pure: several new basic modules made available for general use, see
  2072 also src/Pure/README;
  2073 
  2074 * improved the theory data mechanism to support encapsulation (data
  2075 kind name replaced by private Object.kind, acting as authorization
  2076 key); new type-safe user interface via functor TheoryDataFun; generic
  2077 print_data function becomes basically useless;
  2078 
  2079 * removed global_names compatibility flag -- all theory declarations
  2080 are qualified by default;
  2081 
  2082 * module Pure/Syntax now offers quote / antiquote translation
  2083 functions (useful for Hoare logic etc. with implicit dependencies);
  2084 see HOL/ex/Antiquote for an example use;
  2085 
  2086 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2087 cterm -> thm;
  2088 
  2089 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2090 subgoal;
  2091 
  2092 * Display.print_goals function moved to Locale.print_goals;
  2093 
  2094 * standard print function for goals supports current_goals_markers
  2095 variable for marking begin of proof, end of proof, start of goal; the
  2096 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2097 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2098 for example;
  2099 
  2100 
  2101 
  2102 New in Isabelle98 (January 1998)
  2103 --------------------------------
  2104 
  2105 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2106 
  2107 * changed lexical syntax of terms / types: dots made part of long
  2108 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2109 
  2110 * simpset (and claset) reference variable replaced by functions
  2111 simpset / simpset_ref;
  2112 
  2113 * no longer supports theory aliases (via merge) and non-trivial
  2114 implicit merge of thms' signatures;
  2115 
  2116 * most internal names of constants changed due to qualified names;
  2117 
  2118 * changed Pure/Sequence interface (see Pure/seq.ML);
  2119 
  2120 
  2121 *** General Changes ***
  2122 
  2123 * hierachically structured name spaces (for consts, types, axms, thms
  2124 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2125 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2126 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2127 long_names for fully qualified output names; NOTE: ML programs
  2128 (special tactics, packages etc.) referring to internal names may have
  2129 to be adapted to cope with fully qualified names; in case of severe
  2130 backward campatibility problems try setting 'global_names' at compile
  2131 time to have enrything declared within a flat name space; one may also
  2132 fine tune name declarations in theories via the 'global' and 'local'
  2133 section;
  2134 
  2135 * reimplemented the implicit simpset and claset using the new anytype
  2136 data filed in signatures; references simpset:simpset ref etc. are
  2137 replaced by functions simpset:unit->simpset and
  2138 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2139 to patch your ML files accordingly;
  2140 
  2141 * HTML output now includes theory graph data for display with Java
  2142 applet or isatool browser; data generated automatically via isatool
  2143 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2144 
  2145 * defs may now be conditional; improved rewrite_goals_tac to handle
  2146 conditional equations;
  2147 
  2148 * defs now admits additional type arguments, using TYPE('a) syntax;
  2149 
  2150 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2151 creates a new theory node; implicit merge of thms' signatures is
  2152 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2153 transfer:theory->thm->thm in (rare) cases;
  2154 
  2155 * improved handling of draft signatures / theories; draft thms (and
  2156 ctyps, cterms) are automatically promoted to real ones;
  2157 
  2158 * slightly changed interfaces for oracles: admit many per theory, named
  2159 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2160 
  2161 * print_goals: optional output of const types (set show_consts and
  2162 show_types);
  2163 
  2164 * improved output of warnings (###) and errors (***);
  2165 
  2166 * subgoal_tac displays a warning if the new subgoal has type variables;
  2167 
  2168 * removed old README and Makefiles;
  2169 
  2170 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2171 
  2172 * removed obsolete init_pps and init_database;
  2173 
  2174 * deleted the obsolete tactical STATE, which was declared by
  2175     fun STATE tacfun st = tacfun st st;
  2176 
  2177 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2178 (which abbreviates $HOME);
  2179 
  2180 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2181 use isatool fixseq to adapt your ML programs (this works for fully
  2182 qualified references to the Sequence structure only!);
  2183 
  2184 * use_thy no longer requires writable current directory; it always
  2185 reloads .ML *and* .thy file, if either one is out of date;
  2186 
  2187 
  2188 *** Classical Reasoner ***
  2189 
  2190 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2191 tactics that use classical reasoning to simplify a subgoal without
  2192 splitting it into several subgoals;
  2193 
  2194 * Safe_tac: like safe_tac but uses the default claset;
  2195 
  2196 
  2197 *** Simplifier ***
  2198 
  2199 * added simplification meta rules:
  2200     (asm_)(full_)simplify: simpset -> thm -> thm;
  2201 
  2202 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2203 logics (again);
  2204 
  2205 * added prems argument to simplification procedures;
  2206 
  2207 * HOL, FOL, ZF: added infix function `addsplits':
  2208   instead of `<simpset> setloop (split_tac <thms>)'
  2209   you can simply write `<simpset> addsplits <thms>'
  2210 
  2211 
  2212 *** Syntax ***
  2213 
  2214 * TYPE('a) syntax for type reflection terms;
  2215 
  2216 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2217 
  2218 * pretty printer: changed order of mixfix annotation preference (again!);
  2219 
  2220 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2221 
  2222 
  2223 *** HOL ***
  2224 
  2225 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2226   with `addloop' of the simplifier to faciliate case splitting in premises.
  2227 
  2228 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2229 
  2230 * HOL/Auth: new protocol proofs including some for the Internet
  2231   protocol TLS;
  2232 
  2233 * HOL/Map: new theory of `maps' a la VDM;
  2234 
  2235 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2236 cancelling out common nat summands from =, <, <= (in)equalities, or
  2237 differences; simplification procedures nat_cancel_factor for
  2238 cancelling common factor from =, <, <= (in)equalities over natural
  2239 sums; nat_cancel contains both kinds of procedures, it is installed by
  2240 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2241 
  2242 * HOL/simplifier: terms of the form
  2243   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2244   are rewritten to
  2245   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2246   and those of the form
  2247   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2248   are rewritten to
  2249   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2250 
  2251 * HOL/datatype
  2252   Each datatype `t' now comes with a theorem `split_t_case' 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 
  2260   and a theorem `split_t_case_asm' of the form
  2261 
  2262   P(t_case f1 ... fn x) =
  2263     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2264         ...
  2265        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2266      )
  2267   which can be added to a simpset via `addsplits'. The existing theorems
  2268   expand_list_case and expand_option_case have been renamed to
  2269   split_list_case and split_option_case.
  2270 
  2271 * HOL/Arithmetic:
  2272   - `pred n' is automatically converted to `n-1'.
  2273     Users are strongly encouraged not to use `pred' any longer,
  2274     because it will disappear altogether at some point.
  2275   - Users are strongly encouraged to write "0 < n" rather than
  2276     "n ~= 0". Theorems and proof tools have been modified towards this
  2277     `standard'.
  2278 
  2279 * HOL/Lists:
  2280   the function "set_of_list" has been renamed "set" (and its theorems too);
  2281   the function "nth" now takes its arguments in the reverse order and
  2282   has acquired the infix notation "!" as in "xs!n".
  2283 
  2284 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2285 
  2286 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2287   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2288 
  2289 * HOL/record: extensible records with schematic structural subtyping
  2290 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2291 still lacks various theorems and concrete record syntax;
  2292 
  2293 
  2294 *** HOLCF ***
  2295 
  2296 * removed "axioms" and "generated by" sections;
  2297 
  2298 * replaced "ops" section by extended "consts" section, which is capable of
  2299   handling the continuous function space "->" directly;
  2300 
  2301 * domain package:
  2302   . proves theorems immediately and stores them in the theory,
  2303   . creates hierachical name space,
  2304   . now uses normal mixfix annotations (instead of cinfix...),
  2305   . minor changes to some names and values (for consistency),
  2306   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2307   . separator between mutual domain defs: changed "," to "and",
  2308   . improved handling of sort constraints;  now they have to
  2309     appear on the left-hand side of the equations only;
  2310 
  2311 * fixed LAM <x,y,zs>.b syntax;
  2312 
  2313 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2314 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2315 
  2316 
  2317 *** FOL and ZF ***
  2318 
  2319 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2320   with `addloop' of the simplifier to faciliate case splitting in premises.
  2321 
  2322 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2323 in HOL, they strip ALL and --> from proved theorems;
  2324 
  2325 
  2326 
  2327 New in Isabelle94-8 (May 1997)
  2328 ------------------------------
  2329 
  2330 *** General Changes ***
  2331 
  2332 * new utilities to build / run / maintain Isabelle etc. (in parts
  2333 still somewhat experimental); old Makefiles etc. still functional;
  2334 
  2335 * new 'Isabelle System Manual';
  2336 
  2337 * INSTALL text, together with ./configure and ./build scripts;
  2338 
  2339 * reimplemented type inference for greater efficiency, better error
  2340 messages and clean internal interface;
  2341 
  2342 * prlim command for dealing with lots of subgoals (an easier way of
  2343 setting goals_limit);
  2344 
  2345 
  2346 *** Syntax ***
  2347 
  2348 * supports alternative (named) syntax tables (parser and pretty
  2349 printer); internal interface is provided by add_modesyntax(_i);
  2350 
  2351 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2352 be used in conjunction with the Isabelle symbol font; uses the
  2353 "symbols" syntax table;
  2354 
  2355 * added token_translation interface (may translate name tokens in
  2356 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2357 the current print_mode); IMPORTANT: user print translation functions
  2358 are responsible for marking newly introduced bounds
  2359 (Syntax.mark_boundT);
  2360 
  2361 * token translations for modes "xterm" and "xterm_color" that display
  2362 names in bold, underline etc. or colors (which requires a color
  2363 version of xterm);
  2364 
  2365 * infixes may now be declared with names independent of their syntax;
  2366 
  2367 * added typed_print_translation (like print_translation, but may
  2368 access type of constant);
  2369 
  2370 
  2371 *** Classical Reasoner ***
  2372 
  2373 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2374 some limitations.  Blast_tac...
  2375   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2376   + ignores elimination rules that don't have the correct format
  2377         (the conclusion MUST be a formula variable)
  2378   + ignores types, which can make HOL proofs fail
  2379   + rules must not require higher-order unification, e.g. apply_type in ZF
  2380     [message "Function Var's argument not a bound variable" relates to this]
  2381   + its proof strategy is more general but can actually be slower
  2382 
  2383 * substitution with equality assumptions no longer permutes other
  2384 assumptions;
  2385 
  2386 * minor changes in semantics of addafter (now called addaltern); renamed
  2387 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2388 (and access functions for it);
  2389 
  2390 * improved combination of classical reasoner and simplifier:
  2391   + functions for handling clasimpsets
  2392   + improvement of addss: now the simplifier is called _after_ the
  2393     safe steps.
  2394   + safe variant of addss called addSss: uses safe simplifications
  2395     _during_ the safe steps. It is more complete as it allows multiple
  2396     instantiations of unknowns (e.g. with slow_tac).
  2397 
  2398 *** Simplifier ***
  2399 
  2400 * added interface for simplification procedures (functions that
  2401 produce *proven* rewrite rules on the fly, depending on current
  2402 redex);
  2403 
  2404 * ordering on terms as parameter (used for ordered rewriting);
  2405 
  2406 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2407 
  2408 * the solver is now split into a safe and an unsafe part.
  2409 This should be invisible for the normal user, except that the
  2410 functions setsolver and addsolver have been renamed to setSolver and
  2411 addSolver; added safe_asm_full_simp_tac;
  2412 
  2413 
  2414 *** HOL ***
  2415 
  2416 * a generic induction tactic `induct_tac' which works for all datatypes and
  2417 also for type `nat';
  2418 
  2419 * a generic case distinction tactic `exhaust_tac' which works for all
  2420 datatypes and also for type `nat';
  2421 
  2422 * each datatype comes with a function `size';
  2423 
  2424 * patterns in case expressions allow tuple patterns as arguments to
  2425 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2426 
  2427 * primrec now also works with type nat;
  2428 
  2429 * recdef: a new declaration form, allows general recursive functions to be
  2430 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2431 
  2432 * the constant for negation has been renamed from "not" to "Not" to
  2433 harmonize with FOL, ZF, LK, etc.;
  2434 
  2435 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2436 infinite lists;
  2437 
  2438 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2439 
  2440 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2441 problems in commutative rings, using axiomatic type classes for + and *;
  2442 
  2443 * more examples in HOL/MiniML and HOL/Auth;
  2444 
  2445 * more default rewrite rules for quantifiers, union/intersection;
  2446 
  2447 * a new constant `arbitrary == @x.False';
  2448 
  2449 * HOLCF/IOA replaces old HOL/IOA;
  2450 
  2451 * HOLCF changes: derived all rules and arities
  2452   + axiomatic type classes instead of classes
  2453   + typedef instead of faking type definitions
  2454   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2455   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2456   + eliminated the types void, one, tr
  2457   + use unit lift and bool lift (with translations) instead of one and tr
  2458   + eliminated blift from Lift3.thy (use Def instead of blift)
  2459   all eliminated rules are derived as theorems --> no visible changes ;
  2460 
  2461 
  2462 *** ZF ***
  2463 
  2464 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2465 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2466 as ZF_cs addSIs [equalityI];
  2467 
  2468 
  2469 
  2470 New in Isabelle94-7 (November 96)
  2471 ---------------------------------
  2472 
  2473 * allowing negative levels (as offsets) in prlev and choplev;
  2474 
  2475 * super-linear speedup for large simplifications;
  2476 
  2477 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2478 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2479 FAIL); can suppress it using the command Delsimps (ex_simps @
  2480 all_simps); De Morgan laws are also now included, by default;
  2481 
  2482 * improved printing of ==>  :  ~:
  2483 
  2484 * new object-logic "Sequents" adds linear logic, while replacing LK
  2485 and Modal (thanks to Sara Kalvala);
  2486 
  2487 * HOL/Auth: correctness proofs for authentication protocols;
  2488 
  2489 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2490 examples on HOL/Auth);
  2491 
  2492 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2493 the rewriter and classical reasoner simultaneously;
  2494 
  2495 * function uresult no longer returns theorems in "standard" format;
  2496 regain previous version by: val uresult = standard o uresult;
  2497 
  2498 
  2499 
  2500 New in Isabelle94-6
  2501 -------------------
  2502 
  2503 * oracles -- these establish an interface between Isabelle and trusted
  2504 external reasoners, which may deliver results as theorems;
  2505 
  2506 * proof objects (in particular record all uses of oracles);
  2507 
  2508 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2509 
  2510 * "constdefs" section in theory files;
  2511 
  2512 * "primrec" section (HOL) no longer requires names;
  2513 
  2514 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2515 
  2516 
  2517 
  2518 New in Isabelle94-5
  2519 -------------------
  2520 
  2521 * reduced space requirements;
  2522 
  2523 * automatic HTML generation from theories;
  2524 
  2525 * theory files no longer require "..." (quotes) around most types;
  2526 
  2527 * new examples, including two proofs of the Church-Rosser theorem;
  2528 
  2529 * non-curried (1994) version of HOL is no longer distributed;
  2530 
  2531 
  2532 
  2533 New in Isabelle94-4
  2534 -------------------
  2535 
  2536 * greatly reduced space requirements;
  2537 
  2538 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2539 
  2540 * searchable theorem database (see the section "Retrieving theorems" on
  2541 page 8 of the Reference Manual);
  2542 
  2543 * new examples, including Grabczewski's monumental case study of the
  2544 Axiom of Choice;
  2545 
  2546 * The previous version of HOL renamed to Old_HOL;
  2547 
  2548 * The new version of HOL (previously called CHOL) uses a curried syntax
  2549 for functions.  Application looks like f a b instead of f(a,b);
  2550 
  2551 * Mutually recursive inductive definitions finally work in HOL;
  2552 
  2553 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2554 translates to the operator "split";
  2555 
  2556 
  2557 
  2558 New in Isabelle94-3
  2559 -------------------
  2560 
  2561 * new infix operator, addss, allowing the classical reasoner to
  2562 perform simplification at each step of its search.  Example:
  2563         fast_tac (cs addss ss)
  2564 
  2565 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2566 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2567 look like (a,b) instead of <a,b>;
  2568 
  2569 * PLEASE NOTE: CHOL will eventually replace HOL!
  2570 
  2571 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2572 It translates to the operator "split".  A new theory of integers is available;
  2573 
  2574 * In ZF, integer numerals now denote two's-complement binary integers.
  2575 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2576 
  2577 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2578 of the Axiom of Choice;
  2579 
  2580 
  2581 
  2582 New in Isabelle94-2
  2583 -------------------
  2584 
  2585 * Significantly faster resolution;
  2586 
  2587 * the different sections in a .thy file can now be mixed and repeated
  2588 freely;
  2589 
  2590 * Database of theorems for FOL, HOL and ZF.  New
  2591 commands including qed, qed_goal and bind_thm store theorems in the database.
  2592 
  2593 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2594 a given theory (thms_of), or find out what theory a theorem was proved in
  2595 (theory_of_thm);
  2596 
  2597 * Bugs fixed in the inductive definition and datatype packages;
  2598 
  2599 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2600 and HOL_dup_cs obsolete;
  2601 
  2602 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2603 have been removed;
  2604 
  2605 * Simpler definition of function space in ZF;
  2606 
  2607 * new results about cardinal and ordinal arithmetic in ZF;
  2608 
  2609 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2610 types;
  2611 
  2612 
  2613 $Id$