NEWS
author paulson
Thu Apr 07 18:44:45 2005 +0200 (2005-04-07)
changeset 15682 09a7b8909c4d
parent 15677 8770edbf8f28
child 15696 1da4ce092c0b
permissions -rw-r--r--
removed bad code
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * The type Library.option is no more, along with the exception
    10   Library.OPTION: Isabelle now uses the standard option type.  The
    11   functions the, is_some, is_none, etc. are still in Library, but
    12   the constructors are now SOME and NONE instead of Some and None.
    13   They throw the exception Option.
    14 
    15 * The exception LIST is no more, the standard exceptions Empty and
    16   Subscript, as well as Library.UnequalLengths are used instead.  This
    17   means that function like Library.hd and Library.tl are gone, as the
    18   standard hd and tl functions suffice.
    19 
    20   A number of functions, specifically those in the LIBRARY_CLOSED
    21   signature, are now no longer exported to the top ML level, as they
    22   are variants of standard functions.  The following suggests how
    23   one can translate existing code:
    24 
    25     the x = valOf x
    26     if_none x y = getOpt(x,y)
    27     is_some x = isSome x
    28     apsome f x = Option.map f x
    29     rev_append xs ys = List.revAppend(xs,ys)
    30     nth_elem(i,xs) = List.nth(xs,i)
    31     last_elem xs = List.last xs
    32     flat xss = List.concat xss
    33     seq fs = app fs
    34     partition P xs = List.partition P xs
    35     filter P xs = List.filter P xs
    36     mapfilter f xs = List.mapPartial f xs
    37 
    38   The final four functions, take, drop, foldl, and foldr, are somewhat
    39   more complicated (especially the semantics of take and drop differ
    40   from the standard).
    41 
    42   A simple solution to broken code is to include "open Library" at the
    43   beginning of a structure.  Everything after that will be as before.
    44 
    45 * Document preparation: new antiquotations @{lhs thm} and @{rhs thm}
    46   printing the lhs/rhs of definitions, equations, inequations etc. 
    47 
    48 * isatool usedir: new option -f that allows specification of the ML
    49   file to be used by Isabelle; default is ROOT.ML.
    50 
    51 * Theory headers: the new header syntax for Isar theories is
    52 
    53   theory <name>
    54   imports <theory1> ... <theoryn>
    55   begin
    56 
    57   optionally also with a "files" section. The syntax
    58 
    59   theory <name> = <theory1> + ... + <theoryn>:
    60 
    61   will still be supported for some time but will eventually disappear.
    62   The syntax of old-style theories has not changed.
    63 
    64 * Theory loader: parent theories can now also be referred to via
    65   relative and absolute paths.
    66 
    67 * Provers/quasi.ML:  new transitivity reasoners for transitivity only
    68   and quasi orders.
    69 
    70 * Provers/trancl.ML:  new transitivity reasoner for transitive and
    71   reflexive-transitive closure of relations.
    72 
    73 * Provers/blast.ML:  new reference depth_limit to make blast's depth
    74   limit (previously hard-coded with a value of 20) user-definable.
    75 
    76 * Provers: new version of the subst method, for single-step rewriting: it now
    77   works in bound variable contexts. New is subst (asm), for rewriting an
    78   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    79   subterm than the original subst method, which is still available under the
    80   name simplesubst.
    81 
    82 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    83   More generally, erule now works even if the major premise of the elimination rule
    84   contains !! or ==>.
    85 
    86 * Pure: considerably improved version of 'constdefs' command.  Now
    87   performs automatic type-inference of declared constants; additional
    88   support for local structure declarations (cf. locales and HOL
    89   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    90   to observe strictly sequential dependencies of definitions within a
    91   single 'constdefs' section; moreover, the declared name needs to be
    92   an identifier.  If all fails, consider to fall back on 'consts' and
    93   'defs' separately.
    94 
    95 * Pure: improved indexed syntax and implicit structures.  First of
    96   all, indexed syntax provides a notational device for subscripted
    97   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    98   expressions.  Secondly, in a local context with structure
    99   declarations, number indexes \<^sub>n or the empty index (default
   100   number 1) refer to a certain fixed variable implicitly; option
   101   show_structs controls printing of implicit structures.  Typical
   102   applications of these concepts involve record types and locales.
   103 
   104 * Pure: clear separation of logical types and nonterminals, where the
   105   latter may only occur in 'syntax' specifications or type
   106   abbreviations.  Before that distinction was only partially
   107   implemented via type class "logic" vs. "{}".  Potential
   108   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
   109   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
   110   specifications may require further adaption (e.g. Cube/Base.thy).
   111 
   112 * Pure: removed obsolete type class "logic", use the top sort {}
   113   instead.  Note that non-logical types should be declared as
   114   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
   115   object-logic specifications.
   116 
   117 * Pure: print_tac now outputs the goal through the trace channel.
   118 
   119 * Pure: reference Namespace.unique_names included.  If true the
   120   (shortest) namespace-prefix is printed to disambiguate conflicts (as
   121   yet). If false the first entry wins (as during parsing). Default
   122   value is true.
   123 
   124 * Pure: tuned internal renaming of symbolic identifiers -- attach
   125   primes instead of base 26 numbers.
   126 
   127 * Pure: new flag show_var_qmarks to control printing of leading
   128   question marks of variable names.
   129 
   130 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   131 
   132 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   133   specified in mixfix annotations as "(00...)".
   134 
   135 * Pure/Syntax: 'advanced' translation functions (parse_translation
   136   etc.) may depend on the signature of the theory context being
   137   presently used for parsing/printing, see also isar-ref manual.
   138 
   139 * Pure/Simplifier: simplification procedures may now take the current
   140   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   141   interface), which is very useful for calling the Simplifier
   142   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   143   simprocs is gone -- use prems_of_ss on the simpset instead.
   144   Moreover, the low-level mk_simproc no longer applies Logic.varify
   145   internally, to allow for use in a context of fixed variables.
   146 
   147 * Pure/Simplifier: Command "find_rewrites" takes a string and lists all
   148   equality theorems (not just those with attribute simp!) whose left-hand
   149   side matches the term given via the string. In PG the command can be
   150   activated via Isabelle -> Show me -> matching rewrites.
   151 
   152 * Provers: Simplifier and Classical Reasoner now support proof context
   153   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   154   components are stored in the theory and patched into the
   155   simpset/claset when used in an Isar proof context.  Context
   156   dependent components are maintained by the following theory
   157   operations:
   158 
   159     Simplifier.add_context_simprocs
   160     Simplifier.del_context_simprocs
   161     Simplifier.set_context_subgoaler
   162     Simplifier.reset_context_subgoaler
   163     Simplifier.add_context_looper
   164     Simplifier.del_context_looper
   165     Simplifier.add_context_unsafe_solver
   166     Simplifier.add_context_safe_solver
   167 
   168     Classical.add_context_safe_wrapper
   169     Classical.del_context_safe_wrapper
   170     Classical.add_context_unsafe_wrapper
   171     Classical.del_context_unsafe_wrapper
   172 
   173   IMPORTANT NOTE: proof tools (methods etc.) need to use
   174   local_simpset_of and local_claset_of to instead of the primitive
   175   Simplifier.get_local_simpset and Classical.get_local_claset,
   176   respectively, in order to see the context dependent fields!
   177 
   178 * Document preparation: antiquotations now provide the option
   179   'locale=NAME' to specify an alternative context used for evaluating
   180   and printing the subsequent argument, as in @{thm [locale=LC]
   181   fold_commute}, for example.
   182 
   183 * Document preparation: commands 'display_drafts' and 'print_drafts'
   184   perform simple output of raw sources.  Only those symbols that do
   185   not require additional LaTeX packages (depending on comments in
   186   isabellesym.sty) are displayed properly, everything else is left
   187   verbatim.  We use isatool display and isatool print as front ends;
   188   these are subject to the DVI_VIEWER and PRINT_COMMAND settings,
   189   respectively.
   190 
   191 * Document preparation: Proof scripts as well as some other commands
   192   such as ML or parse/print_translation can now be hidden in the document.
   193   Hiding is enabled by default, and can be disabled either via the option
   194   '-H false' of isatool usedir or by resetting the reference variable
   195   IsarOutput.hide_commands. Additional commands to be hidden may be
   196   declared using IsarOutput.add_hidden_commands.
   197 
   198 * ML: output via the Isabelle channels of writeln/warning/error
   199   etc. is now passed through Output.output, with a hook for arbitrary
   200   transformations depending on the print_mode (cf. Output.add_mode --
   201   the first active mode that provides a output function wins).
   202   Already formatted output may be embedded into further text via
   203   Output.raw; the result of Pretty.string_of/str_of and derived
   204   functions (string_of_term/cterm/thm etc.) is already marked raw to
   205   accommodate easy composition of diagnostic messages etc.
   206   Programmers rarely need to care about Output.output or Output.raw at
   207   all, with some notable exceptions: Output.output is required when
   208   bypassing the standard channels (writeln etc.), or in token
   209   translations to produce properly formatted results; Output.raw is
   210   required when capturing already output material that will eventually
   211   be presented to the user a second time.  For the default print mode,
   212   both Output.output and Output.raw have no effect.
   213 
   214 
   215 *** Isar ***
   216 
   217 * Debugging: new reference Toplevel.debug; default false.
   218   Set to make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   219   
   220 * Locales:
   221   - "includes" disallowed in declaration of named locales (command "locale").
   222   - Fixed parameter management in theorem generation for goals with "includes".
   223     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   224 
   225 * New syntax
   226 
   227     <theorem_name> (<index>, ..., <index>-<index>, ...)
   228 
   229   for referring to specific theorems in a named list of theorems via
   230   indices.
   231 
   232 *** HOL ***
   233 
   234 * Datatype induction via method `induct' now preserves the name of the
   235   induction variable. For example, when proving P(xs::'a list) by induction
   236   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   237   P(list) ==> P(a#list) as previously.
   238 
   239 * HOL/record: reimplementation of records. Improved scalability for
   240   records with many fields, avoiding performance problems for type
   241   inference. Records are no longer composed of nested field types, but
   242   of nested extension types. Therefore the record type only grows
   243   linear in the number of extensions and not in the number of fields.
   244   The top-level (users) view on records is preserved.  Potential
   245   INCOMPATIBILITY only in strange cases, where the theory depends on
   246   the old record representation. The type generated for a record is
   247   called <record_name>_ext_type.
   248 
   249 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   250   enabled to skip the proofs triggered by a record definition or a
   251   simproc (if quick_and_dirty is enabled). Definitions of large
   252   records can take quite long.
   253 
   254 * HOL/record: "record_upd_simproc" for simplification of multiple
   255   record updates enabled by default.  Moreover, trivial updates are
   256   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   257   occasionally, since simplification is more powerful by default.
   258 
   259 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   260 
   261   syntax (epsilon)
   262     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   263 
   264   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   265   and x-symbol; use option '-m epsilon' to get it actually printed.
   266   Moreover, the mathematically important symbolic identifier
   267   \<epsilon> becomes available as variable, constant etc.
   268 
   269 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   270   Similarly for all quantifiers: "ALL x > y" etc.
   271   The x-symbol for >= is \<ge>.
   272 
   273 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}"
   274            (and similarly for "\<in>" instead of ":")
   275 
   276 * HOL/SetInterval: The syntax for open intervals has changed:
   277 
   278   Old         New
   279   {..n(}   -> {..<n}
   280   {)n..}   -> {n<..}
   281   {m..n(}  -> {m..<n}
   282   {)m..n}  -> {m<..n}
   283   {)m..n(} -> {m<..<n}
   284 
   285   The old syntax is still supported but will disappear in the future.
   286   For conversion use the following emacs search and replace patterns:
   287 
   288   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   289   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   290 
   291   They are not perfect but work quite well.
   292 
   293 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   294 
   295   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   296   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   297 
   298   There is new syntax for summation over finite sets:
   299 
   300   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   301   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   302   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   303   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   304 
   305   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   306   now translates into 'setsum' as above.
   307 
   308 * HOL: Finite set induction: In Isar proofs, the insert case is now
   309   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   310 
   311 * HOL/Simplifier:
   312 
   313   - Is now set up to reason about transitivity chains involving "trancl"
   314   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   315   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   316   occasionally as simplification may now solve more goals than previously.
   317 
   318   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   319   all partial orders (class "order"), in particular numbers and sets. For
   320   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   321 
   322   - Simproc for "let x = a in f x"
   323   If a is a free or bound variable or a constant then the let is unfolded.
   324   Otherwise first a is simplified to a', and then f a' is simplified to
   325   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   326   otherwise we unfold the let and arrive at g. The simproc can be 
   327   enabled/disabled by the reference use_let_simproc. Potential
   328   INCOMPATIBILITY since simplification is more powerful by default.
   329  
   330 * HOL: new 'isatool dimacs2hol' to convert files in DIMACS CNF format
   331   (containing Boolean satisfiability problems) into Isabelle/HOL theories.
   332 
   333 
   334 *** HOLCF ***
   335 
   336 * HOLCF: discontinued special version of 'constdefs' (which used to
   337   support continuous functions) in favor of the general Pure one with
   338   full type-inference.
   339 
   340 
   341 *** ZF ***
   342 
   343 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   344   First Isomorphism Theorem (on quotienting by the kernel of a
   345   homomorphism).
   346 
   347 * ZF/Simplifier: install second copy of type solver that actually
   348   makes use of TC rules declared to Isar proof contexts (or locales);
   349   the old version is still required for ML proof scripts.
   350 
   351 
   352 
   353 New in Isabelle2004 (April 2004)
   354 --------------------------------
   355 
   356 *** General ***
   357 
   358 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   359   Replaces linorder.ML.
   360 
   361 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   362   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   363   (\<a>...\<z>), are now considered normal letters, and can therefore
   364   be used anywhere where an ASCII letter (a...zA...Z) has until
   365   now. COMPATIBILITY: This obviously changes the parsing of some
   366   terms, especially where a symbol has been used as a binder, say
   367   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   368   as an identifier.  Fix it by inserting a space around former
   369   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   370   existing theory and ML files.
   371 
   372 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   373 
   374 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   375   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   376   a normal (but invisible) letter. For multiple letter subscripts repeat
   377   \<^isub> like this: x\<^isub>1\<^isub>2.
   378 
   379 * Pure: There are now sub-/superscripts that can span more than one
   380   character. Text between \<^bsub> and \<^esub> is set in subscript in
   381   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   382   superscript. The new control characters are not identifier parts.
   383 
   384 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   385   content of "..." to the latex file instead of \isacntrl... . The "..."
   386   may consist of any printable characters excluding the end bracket >.
   387 
   388 * Pure: Using new Isar command "finalconsts" (or the ML functions
   389   Theory.add_finals or Theory.add_finals_i) it is now possible to
   390   declare constants "final", which prevents their being given a definition
   391   later.  It is useful for constants whose behaviour is fixed axiomatically
   392   rather than definitionally, such as the meta-logic connectives.
   393 
   394 * Pure: 'instance' now handles general arities with general sorts
   395   (i.e. intersections of classes),
   396 
   397 * Presentation: generated HTML now uses a CSS style sheet to make layout
   398   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   399   It can be changed to alter the colors/layout of generated pages.
   400 
   401 
   402 *** Isar ***
   403 
   404 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   405   cut_tac, subgoal_tac and thin_tac:
   406   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   407     locales are no longer forced to write Isar proof scripts.
   408     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   409     emulations.
   410   - INCOMPATIBILITY: names of variables to be instantiated may no
   411     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   412     This is consistent with the instantiation attribute "where".
   413 
   414 * Attributes "where" and "of":
   415   - Now take type variables of instantiated theorem into account when reading
   416     the instantiation string.  This fixes a bug that caused instantiated
   417     theorems to have too special types in some circumstances.
   418   - "where" permits explicit instantiations of type variables.
   419 
   420 * Calculation commands "moreover" and "also" no longer interfere with
   421   current facts ("this"), admitting arbitrary combinations with "then"
   422   and derived forms.
   423 
   424 * Locales:
   425   - Goal statements involving the context element "includes" no longer
   426     generate theorems with internal delta predicates (those ending on
   427     "_axioms") in the premise.
   428     Resolve particular premise with <locale>.intro to obtain old form.
   429   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   430     specification and "includes" elements in goal statement.
   431   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   432     [intro?] and [elim?] (respectively) by default.
   433   - Experimental command for instantiation of locales in proof contexts:
   434         instantiate <label>[<attrs>]: <loc>
   435     Instantiates locale <loc> and adds all its theorems to the current context
   436     taking into account their attributes.  Label and attrs are optional
   437     modifiers, like in theorem declarations.  If present, names of
   438     instantiated theorems are qualified with <label>, and the attributes
   439     <attrs> are applied after any attributes these theorems might have already.
   440       If the locale has assumptions, a chained fact of the form
   441     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   442     are derived.  The command does not support old-style locales declared
   443     with "locale (open)".
   444       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   445 
   446 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   447   (Isar) contexts.
   448 
   449 
   450 *** HOL ***
   451 
   452 * Proof import: new image HOL4 contains the imported library from
   453   the HOL4 system with about 2500 theorems. It is imported by
   454   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   455   can be used like any other Isabelle image.  See
   456   HOL/Import/HOL/README for more information.
   457 
   458 * Simplifier:
   459   - Much improved handling of linear and partial orders.
   460     Reasoners for linear and partial orders are set up for type classes
   461     "linorder" and "order" respectively, and are added to the default simpset
   462     as solvers.  This means that the simplifier can build transitivity chains
   463     to solve goals from the assumptions.
   464   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   465     of blast or auto after simplification become unnecessary because the goal
   466     is solved by simplification already.
   467 
   468 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   469     all proved in axiomatic type classes for semirings, rings and fields.
   470 
   471 * Numerics:
   472   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   473     now formalized using the Ring_and_Field theory mentioned above.
   474   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   475     than before, because now they are set up once in a generic manner.
   476   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   477     Look for the general versions in Ring_and_Field (and Power if they concern
   478     exponentiation).
   479 
   480 * Type "rat" of the rational numbers is now available in HOL-Complex.
   481 
   482 * Records:
   483   - Record types are now by default printed with their type abbreviation
   484     instead of the list of all field types. This can be configured via
   485     the reference "print_record_type_abbr".
   486   - Simproc "record_upd_simproc" for simplification of multiple updates added
   487     (not enabled by default).
   488   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   489     EX x. x = sel r to True (not enabled by default).
   490   - Tactic "record_split_simp_tac" to split and simplify records added.
   491 
   492 * 'specification' command added, allowing for definition by
   493   specification.  There is also an 'ax_specification' command that
   494   introduces the new constants axiomatically.
   495 
   496 * arith(_tac) is now able to generate counterexamples for reals as well.
   497 
   498 * HOL-Algebra: new locale "ring" for non-commutative rings.
   499 
   500 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   501   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   502 
   503 * HOL-Matrix: a first theory for matrices in HOL with an application of
   504   matrix theory to linear programming.
   505 
   506 * Unions and Intersections:
   507   The latex output syntax of UN and INT has been changed
   508   from "\Union x \in A. B" to "\Union_{x \in A} B"
   509   i.e. the index formulae has become a subscript.
   510   Similarly for "\Union x. B", and for \Inter instead of \Union.
   511 
   512 * Unions and Intersections over Intervals:
   513   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   514   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   515   like in normal math, and corresponding versions for < and for intersection.
   516 
   517 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   518   lexicographic dictonary ordering has been added as "lexord".
   519 
   520 * ML: the legacy theory structures Int and List have been removed. They had
   521   conflicted with ML Basis Library structures having the same names.
   522 
   523 * 'refute' command added to search for (finite) countermodels.  Only works
   524   for a fragment of HOL.  The installation of an external SAT solver is
   525   highly recommended.  See "HOL/Refute.thy" for details.
   526 
   527 * 'quickcheck' command: Allows to find counterexamples by evaluating
   528   formulae under an assignment of free variables to random values.
   529   In contrast to 'refute', it can deal with inductive datatypes,
   530   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   531   for examples.
   532 
   533 
   534 *** HOLCF ***
   535 
   536 * Streams now come with concatenation and are part of the HOLCF image
   537 
   538 
   539 
   540 New in Isabelle2003 (May 2003)
   541 ------------------------------
   542 
   543 *** General ***
   544 
   545 * Provers/simplifier:
   546 
   547   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   548     Assumptions are now subject to complete mutual simplification,
   549     not just from left to right. The simplifier now preserves
   550     the order of assumptions.
   551 
   552     Potential INCOMPATIBILITY:
   553 
   554     -- simp sometimes diverges where the old version did
   555        not, e.g. invoking simp on the goal
   556 
   557         [| P (f x); y = x; f x = f y |] ==> Q
   558 
   559        now gives rise to the infinite reduction sequence
   560 
   561         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   562 
   563        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   564        kind of problem.
   565 
   566     -- Tactics combining classical reasoner and simplification (such as auto)
   567        are also affected by this change, because many of them rely on
   568        simp. They may sometimes diverge as well or yield a different numbers
   569        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   570        in case of problems. Sometimes subsequent calls to the classical
   571        reasoner will fail because a preceeding call to the simplifier too
   572        eagerly simplified the goal, e.g. deleted redundant premises.
   573 
   574   - The simplifier trace now shows the names of the applied rewrite rules
   575 
   576   - You can limit the number of recursive invocations of the simplifier
   577     during conditional rewriting (where the simplifie tries to solve the
   578     conditions before applying the rewrite rule):
   579     ML "simp_depth_limit := n"
   580     where n is an integer. Thus you can force termination where previously
   581     the simplifier would diverge.
   582 
   583   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   584 
   585   - No longer aborts on failed congruence proof.  Instead, the
   586     congruence is ignored.
   587 
   588 * Pure: New generic framework for extracting programs from constructive
   589   proofs. See HOL/Extraction.thy for an example instantiation, as well
   590   as HOL/Extraction for some case studies.
   591 
   592 * Pure: The main goal of the proof state is no longer shown by default, only
   593 the subgoals. This behaviour is controlled by a new flag.
   594    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   595 (ML: Proof.show_main_goal).
   596 
   597 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   598 rules whose conclusion matches subgoal 1:
   599       PG menu: Isabelle/Isar -> Show me -> matching rules
   600 The rules are ordered by how closely they match the subgoal.
   601 In particular, rules that solve a subgoal outright are displayed first
   602 (or rather last, the way they are printed).
   603 (ML: ProofGeneral.print_intros())
   604 
   605 * Pure: New flag trace_unify_fail causes unification to print
   606 diagnostic information (PG: in trace buffer) when it fails. This is
   607 useful for figuring out why single step proofs like rule, erule or
   608 assumption failed.
   609 
   610 * Pure: Locale specifications now produce predicate definitions
   611 according to the body of text (covering assumptions modulo local
   612 definitions); predicate "loc_axioms" covers newly introduced text,
   613 while "loc" is cumulative wrt. all included locale expressions; the
   614 latter view is presented only on export into the global theory
   615 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   616 on the old view without predicates;
   617 
   618 * Pure: predefined locales "var" and "struct" are useful for sharing
   619 parameters (as in CASL, for example); just specify something like
   620 ``var x + var y + struct M'' as import;
   621 
   622 * Pure: improved thms_containing: proper indexing of facts instead of
   623 raw theorems; check validity of results wrt. current name space;
   624 include local facts of proof configuration (also covers active
   625 locales), cover fixed variables in index; may use "_" in term
   626 specification; an optional limit for the number of printed facts may
   627 be given (the default is 40);
   628 
   629 * Pure: disallow duplicate fact bindings within new-style theory files
   630 (batch-mode only);
   631 
   632 * Provers: improved induct method: assumptions introduced by case
   633 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   634 the goal statement); "foo" still refers to all facts collectively;
   635 
   636 * Provers: the function blast.overloaded has been removed: all constants
   637 are regarded as potentially overloaded, which improves robustness in exchange
   638 for slight decrease in efficiency;
   639 
   640 * Provers/linorder: New generic prover for transitivity reasoning over
   641 linear orders.  Note: this prover is not efficient!
   642 
   643 * Isar: preview of problems to finish 'show' now produce an error
   644 rather than just a warning (in interactive mode);
   645 
   646 
   647 *** HOL ***
   648 
   649 * arith(_tac)
   650 
   651  - Produces a counter example if it cannot prove a goal.
   652    Note that the counter example may be spurious if the goal is not a formula
   653    of quantifier-free linear arithmetic.
   654    In ProofGeneral the counter example appears in the trace buffer.
   655 
   656  - Knows about div k and mod k where k is a numeral of type nat or int.
   657 
   658  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   659    linear arithmetic fails. This takes account of quantifiers and divisibility.
   660    Presburger arithmetic can also be called explicitly via presburger(_tac).
   661 
   662 * simp's arithmetic capabilities have been enhanced a bit: it now
   663 takes ~= in premises into account (by performing a case split);
   664 
   665 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   666 are distributed over a sum of terms;
   667 
   668 * New tactic "trans_tac" and method "trans" instantiate
   669 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   670 "<=", "<" and "=").
   671 
   672 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   673 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   674 
   675 * 'typedef' command has new option "open" to suppress the set
   676 definition;
   677 
   678 * functions Min and Max on finite sets have been introduced (theory
   679 Finite_Set);
   680 
   681 * attribute [symmetric] now works for relations as well; it turns
   682 (x,y) : R^-1 into (y,x) : R, and vice versa;
   683 
   684 * induct over a !!-quantified statement (say !!x1..xn):
   685   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   686 
   687 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   688 %x. None. Warning: empty_def now refers to the previously hidden definition
   689 of the empty set.
   690 
   691 * Algebra: formalization of classical algebra.  Intended as base for
   692 any algebraic development in Isabelle.  Currently covers group theory
   693 (up to Sylow's theorem) and ring theory (Universal Property of
   694 Univariate Polynomials).  Contributions welcome;
   695 
   696 * GroupTheory: deleted, since its material has been moved to Algebra;
   697 
   698 * Complex: new directory of the complex numbers with numeric constants,
   699 nonstandard complex numbers, and some complex analysis, standard and
   700 nonstandard (Jacques Fleuriot);
   701 
   702 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   703 
   704 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   705 Fleuriot);
   706 
   707 * Real/HahnBanach: updated and adapted to locales;
   708 
   709 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   710 Gray and Kramer);
   711 
   712 * UNITY: added the Meier-Sanders theory of progress sets;
   713 
   714 * MicroJava: bytecode verifier and lightweight bytecode verifier
   715 as abstract algorithms, instantiated to the JVM;
   716 
   717 * Bali: Java source language formalization. Type system, operational
   718 semantics, axiomatic semantics. Supported language features:
   719 classes, interfaces, objects,virtual methods, static methods,
   720 static/instance fields, arrays, access modifiers, definite
   721 assignment, exceptions.
   722 
   723 
   724 *** ZF ***
   725 
   726 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   727 universe, etc.);
   728 
   729 * Main ZF: virtually all theories converted to new-style format;
   730 
   731 
   732 *** ML ***
   733 
   734 * Pure: Tactic.prove provides sane interface for internal proofs;
   735 omits the infamous "standard" operation, so this is more appropriate
   736 than prove_goalw_cterm in many situations (e.g. in simprocs);
   737 
   738 * Pure: improved error reporting of simprocs;
   739 
   740 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   741 up simprocs;
   742 
   743 
   744 *** Document preparation ***
   745 
   746 * uses \par instead of \\ for line breaks in theory text. This may
   747 shift some page breaks in large documents. To get the old behaviour
   748 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   749 
   750 * minimized dependencies of isabelle.sty and isabellesym.sty on
   751 other packages
   752 
   753 * \<euro> now needs package babel/greek instead of marvosym (which
   754 broke \Rightarrow)
   755 
   756 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   757 textcomp package)
   758 
   759 
   760 
   761 New in Isabelle2002 (March 2002)
   762 --------------------------------
   763 
   764 *** Document preparation ***
   765 
   766 * greatly simplified document preparation setup, including more
   767 graceful interpretation of isatool usedir -i/-d/-D options, and more
   768 instructive isatool mkdir; users should basically be able to get
   769 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   770 users may run a separate document processing stage manually like this:
   771 "isatool usedir -D output HOL Test && isatool document Test/output";
   772 
   773 * theory dependency graph may now be incorporated into documents;
   774 isatool usedir -g true will produce session_graph.eps/.pdf for use
   775 with \includegraphics of LaTeX;
   776 
   777 * proper spacing of consecutive markup elements, especially text
   778 blocks after section headings;
   779 
   780 * support bold style (for single symbols only), input syntax is like
   781 this: "\<^bold>\<alpha>" or "\<^bold>A";
   782 
   783 * \<bullet> is now output as bold \cdot by default, which looks much
   784 better in printed text;
   785 
   786 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   787 note that these symbols are currently unavailable in Proof General /
   788 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   789 
   790 * isatool latex no longer depends on changed TEXINPUTS, instead
   791 isatool document copies the Isabelle style files to the target
   792 location;
   793 
   794 
   795 *** Isar ***
   796 
   797 * Pure/Provers: improved proof by cases and induction;
   798   - 'case' command admits impromptu naming of parameters (such as
   799     "case (Suc n)");
   800   - 'induct' method divinates rule instantiation from the inductive
   801     claim; no longer requires excessive ?P bindings for proper
   802     instantiation of cases;
   803   - 'induct' method properly enumerates all possibilities of set/type
   804     rules; as a consequence facts may be also passed through *type*
   805     rules without further ado;
   806   - 'induct' method now derives symbolic cases from the *rulified*
   807     rule (before it used to rulify cases stemming from the internal
   808     atomized version); this means that the context of a non-atomic
   809     statement becomes is included in the hypothesis, avoiding the
   810     slightly cumbersome show "PROP ?case" form;
   811   - 'induct' may now use elim-style induction rules without chaining
   812     facts, using ``missing'' premises from the goal state; this allows
   813     rules stemming from inductive sets to be applied in unstructured
   814     scripts, while still benefitting from proper handling of non-atomic
   815     statements; NB: major inductive premises need to be put first, all
   816     the rest of the goal is passed through the induction;
   817   - 'induct' proper support for mutual induction involving non-atomic
   818     rule statements (uses the new concept of simultaneous goals, see
   819     below);
   820   - append all possible rule selections, but only use the first
   821     success (no backtracking);
   822   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   823   - undeclared rule case names default to numbers 1, 2, 3, ...;
   824   - added 'print_induct_rules' (covered by help item in recent Proof
   825     General versions);
   826   - moved induct/cases attributes to Pure, methods to Provers;
   827   - generic method setup instantiated for FOL and HOL;
   828 
   829 * Pure: support multiple simultaneous goal statements, for example
   830 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   831 meta-level mechanism, this acts as if several individual goals had
   832 been stated separately; in particular common proof methods need to be
   833 repeated in order to cover all claims; note that a single elimination
   834 step is *not* sufficient to establish the two conjunctions, so this
   835 fails:
   836 
   837   assume "A & B" then have A and B ..   (*".." fails*)
   838 
   839 better use "obtain" in situations as above; alternative refer to
   840 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   841 
   842 * Pure: proper integration with ``locales''; unlike the original
   843 version by Florian Kammller, Isar locales package high-level proof
   844 contexts rather than raw logical ones (e.g. we admit to include
   845 attributes everywhere); operations on locales include merge and
   846 rename; support for implicit arguments (``structures''); simultaneous
   847 type-inference over imports and text; see also HOL/ex/Locales.thy for
   848 some examples;
   849 
   850 * Pure: the following commands have been ``localized'', supporting a
   851 target locale specification "(in name)": 'lemma', 'theorem',
   852 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   853 stored both within the locale and at the theory level (exported and
   854 qualified by the locale name);
   855 
   856 * Pure: theory goals may now be specified in ``long'' form, with
   857 ad-hoc contexts consisting of arbitrary locale elements. for example
   858 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   859 definitions may be given, too); the result is a meta-level rule with
   860 the context elements being discharged in the obvious way;
   861 
   862 * Pure: new proof command 'using' allows to augment currently used
   863 facts after a goal statement ('using' is syntactically analogous to
   864 'apply', but acts on the goal's facts only); this allows chained facts
   865 to be separated into parts given before and after a claim, as in
   866 ``from a and b have C using d and e <proof>'';
   867 
   868 * Pure: renamed "antecedent" case to "rule_context";
   869 
   870 * Pure: new 'judgment' command records explicit information about the
   871 object-logic embedding (used by several tools internally); no longer
   872 use hard-wired "Trueprop";
   873 
   874 * Pure: added 'corollary' command;
   875 
   876 * Pure: fixed 'token_translation' command;
   877 
   878 * Pure: removed obsolete 'exported' attribute;
   879 
   880 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   881 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   882 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   883 
   884 * Pure: method 'atomize' presents local goal premises as object-level
   885 statements (atomic meta-level propositions); setup controlled via
   886 rewrite rules declarations of 'atomize' attribute; example
   887 application: 'induct' method with proper rule statements in improper
   888 proof *scripts*;
   889 
   890 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   891 now consider the syntactic context of assumptions, giving a better
   892 chance to get type-inference of the arguments right (this is
   893 especially important for locales);
   894 
   895 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   896 mode;
   897 
   898 * Pure/obtain: the formal conclusion "thesis", being marked as
   899 ``internal'', may no longer be reference directly in the text;
   900 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   901 situations;
   902 
   903 * Pure: generic 'sym' attribute which declares a rule both as pure
   904 'elim?' and for the 'symmetric' operation;
   905 
   906 * Pure: marginal comments ``--'' may now occur just anywhere in the
   907 text; the fixed correlation with particular command syntax has been
   908 discontinued;
   909 
   910 * Pure: new method 'rules' is particularly well-suited for proof
   911 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   912 but often produces more compact proof terms with less detours;
   913 
   914 * Pure/Provers/classical: simplified integration with pure rule
   915 attributes and methods; the classical "intro?/elim?/dest?"
   916 declarations coincide with the pure ones; the "rule" method no longer
   917 includes classically swapped intros; "intro" and "elim" methods no
   918 longer pick rules from the context; also got rid of ML declarations
   919 AddXIs/AddXEs/AddXDs; all of this has some potential for
   920 INCOMPATIBILITY;
   921 
   922 * Provers/classical: attribute 'swapped' produces classical inversions
   923 of introduction rules;
   924 
   925 * Provers/simplifier: 'simplified' attribute may refer to explicit
   926 rules instead of full simplifier context; 'iff' attribute handles
   927 conditional rules;
   928 
   929 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   930 
   931 * HOL: 'recdef' now fails on unfinished automated proofs, use
   932 "(permissive)" option to recover old behavior;
   933 
   934 * HOL: 'inductive' no longer features separate (collective) attributes
   935 for 'intros' (was found too confusing);
   936 
   937 * HOL: properly declared induction rules less_induct and
   938 wf_induct_rule;
   939 
   940 
   941 *** HOL ***
   942 
   943 * HOL: moved over to sane numeral syntax; the new policy is as
   944 follows:
   945 
   946   - 0 and 1 are polymorphic constants, which are defined on any
   947   numeric type (nat, int, real etc.);
   948 
   949   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   950   binary representation internally;
   951 
   952   - type nat has special constructor Suc, and generally prefers Suc 0
   953   over 1::nat and Suc (Suc 0) over 2::nat;
   954 
   955 This change may cause significant problems of INCOMPATIBILITY; here
   956 are some hints on converting existing sources:
   957 
   958   - due to the new "num" token, "-0" and "-1" etc. are now atomic
   959   entities, so expressions involving "-" (unary or binary minus) need
   960   to be spaced properly;
   961 
   962   - existing occurrences of "1" may need to be constraint "1::nat" or
   963   even replaced by Suc 0; similar for old "2";
   964 
   965   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
   966 
   967   - remove all special provisions on numerals in proofs;
   968 
   969 * HOL: simp rules nat_number expand numerals on nat to Suc/0
   970 representation (depends on bin_arith_simps in the default context);
   971 
   972 * HOL: symbolic syntax for x^2 (numeral 2);
   973 
   974 * HOL: the class of all HOL types is now called "type" rather than
   975 "term"; INCOMPATIBILITY, need to adapt references to this type class
   976 in axclass/classes, instance/arities, and (usually rare) occurrences
   977 in typings (of consts etc.); internally the class is called
   978 "HOL.type", ML programs should refer to HOLogic.typeS;
   979 
   980 * HOL/record package improvements:
   981   - new derived operations "fields" to build a partial record section,
   982     "extend" to promote a fixed record to a record scheme, and
   983     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
   984     declared as simp by default;
   985   - shared operations ("more", "fields", etc.) now need to be always
   986     qualified) --- potential INCOMPATIBILITY;
   987   - removed "make_scheme" operations (use "make" with "extend") --
   988     INCOMPATIBILITY;
   989   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
   990   - provides cases/induct rules for use with corresponding Isar
   991     methods (for concrete records, record schemes, concrete more
   992     parts, and schematic more parts -- in that order);
   993   - internal definitions directly based on a light-weight abstract
   994     theory of product types over typedef rather than datatype;
   995 
   996 * HOL: generic code generator for generating executable ML code from
   997 specifications; specific support for HOL constructs such as inductive
   998 datatypes and sets, as well as recursive functions; can be invoked
   999 via 'generate_code' theory section;
  1000 
  1001 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1002 
  1003 * HOL: consolidated and renamed several theories.  In particular:
  1004         Ord.thy has been absorbed into HOL.thy
  1005         String.thy has been absorbed into List.thy
  1006 
  1007 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1008 (beware of argument permutation!);
  1009 
  1010 * HOL: linorder_less_split superseded by linorder_cases;
  1011 
  1012 * HOL/List: "nodups" renamed to "distinct";
  1013 
  1014 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1015 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1016   - Ex_def has changed, now need to use some_eq_ex
  1017 
  1018 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1019 in this (rare) case use:
  1020 
  1021   delSWrapper "split_all_tac"
  1022   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1023 
  1024 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1025 MAY FAIL;
  1026 
  1027 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1028 Isabelle's type classes, ^ on functions and relations has too general
  1029 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1030 necessary to attach explicit type constraints;
  1031 
  1032 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1033 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1034 renamed accordingly (eg "compI" -> "rel_compI").
  1035 
  1036 * HOL: syntax translations now work properly with numerals and records
  1037 expressions;
  1038 
  1039 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1040 of "lam" -- INCOMPATIBILITY;
  1041 
  1042 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1043 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1044 renamed "Product_Type.unit";
  1045 
  1046 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1047 
  1048 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1049 the "cases" method);
  1050 
  1051 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1052 Florian Kammller);
  1053 
  1054 * HOL/IMP: updated and converted to new-style theory format; several
  1055 parts turned into readable document, with proper Isar proof texts and
  1056 some explanations (by Gerwin Klein);
  1057 
  1058 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1059 
  1060 * HOL-Hyperreal is now a logic image;
  1061 
  1062 
  1063 *** HOLCF ***
  1064 
  1065 * Isar: consts/constdefs supports mixfix syntax for continuous
  1066 operations;
  1067 
  1068 * Isar: domain package adapted to new-style theory format, e.g. see
  1069 HOLCF/ex/Dnat.thy;
  1070 
  1071 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1072 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1073 lift.induct_tac, always use UU instead of Undef;
  1074 
  1075 * HOLCF/IMP: updated and converted to new-style theory;
  1076 
  1077 
  1078 *** ZF ***
  1079 
  1080 * Isar: proper integration of logic-specific tools and packages,
  1081 including theory commands '(co)inductive', '(co)datatype',
  1082 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1083 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1084 
  1085 * theory Main no longer includes AC; for the Axiom of Choice, base
  1086 your theory on Main_ZFC;
  1087 
  1088 * the integer library now covers quotients and remainders, with many
  1089 laws relating division to addition, multiplication, etc.;
  1090 
  1091 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1092 typeless version of the formalism;
  1093 
  1094 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1095 format;
  1096 
  1097 * ZF/Induct: new directory for examples of inductive definitions,
  1098 including theory Multiset for multiset orderings; converted to
  1099 new-style theory format;
  1100 
  1101 * ZF: many new theorems about lists, ordinals, etc.;
  1102 
  1103 
  1104 *** General ***
  1105 
  1106 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1107 variable proof controls level of detail: 0 = no proofs (only oracle
  1108 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1109 also ref manual for further ML interfaces;
  1110 
  1111 * Pure/axclass: removed obsolete ML interface
  1112 goal_subclass/goal_arity;
  1113 
  1114 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1115 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1116 separate tokens, so expressions involving minus need to be spaced
  1117 properly;
  1118 
  1119 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1120 rather than "infixl" or "infixr";
  1121 
  1122 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1123 sort constraint specifications in type inference; e.g. "x::_::foo"
  1124 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1125 type variable);
  1126 
  1127 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1128 control output of nested => (types); the default behavior is
  1129 "type_brackets";
  1130 
  1131 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1132 tokens into AST constants;
  1133 
  1134 * Pure/syntax: prefer later declarations of translations and print
  1135 translation functions; potential INCOMPATIBILITY: need to reverse
  1136 multiple declarations for same syntax element constant;
  1137 
  1138 * Pure/show_hyps reset by default (in accordance to existing Isar
  1139 practice);
  1140 
  1141 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1142 addSafter;
  1143 
  1144 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1145 as well;
  1146 
  1147 * system: tested support for MacOS X; should be able to get Isabelle +
  1148 Proof General to work in a plain Terminal after installing Poly/ML
  1149 (e.g. from the Isabelle distribution area) and GNU bash alone
  1150 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1151 support requires further installations, e.g. from
  1152 http://fink.sourceforge.net/);
  1153 
  1154 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1155 
  1156 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1157 of 40 MB), cf. ML_OPTIONS;
  1158 
  1159 * system: Proof General keywords specification is now part of the
  1160 Isabelle distribution (see etc/isar-keywords.el);
  1161 
  1162 * system: support for persistent Proof General sessions (refrain from
  1163 outdating all loaded theories on startup); user may create writable
  1164 logic images like this: ``isabelle -q HOL Test'';
  1165 
  1166 * system: smart selection of Isabelle process versus Isabelle
  1167 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1168 run both "isabelle" and "Isabelle" even if file names are badly
  1169 damaged (executable inspects the case of the first letter of its own
  1170 name); added separate "isabelle-process" and "isabelle-interface";
  1171 
  1172 * system: refrain from any attempt at filtering input streams; no
  1173 longer support ``8bit'' encoding of old isabelle font, instead proper
  1174 iso-latin characters may now be used; the related isatools
  1175 "symbolinput" and "nonascii" have disappeared as well;
  1176 
  1177 * system: removed old "xterm" interface (the print modes "xterm" and
  1178 "xterm_color" are still available for direct use in a suitable
  1179 terminal);
  1180 
  1181 
  1182 
  1183 New in Isabelle99-2 (February 2001)
  1184 -----------------------------------
  1185 
  1186 *** Overview of INCOMPATIBILITIES ***
  1187 
  1188 * HOL: please note that theories in the Library and elsewhere often use the
  1189 new-style (Isar) format; to refer to their theorems in an ML script you must
  1190 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1191 
  1192 * HOL: inductive package no longer splits induction rule aggressively,
  1193 but only as far as specified by the introductions given; the old
  1194 format may be recovered via ML function complete_split_rule or attribute
  1195 'split_rule (complete)';
  1196 
  1197 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1198 gfp_Tarski to gfp_unfold;
  1199 
  1200 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1201 
  1202 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1203 relation); infix "^^" has been renamed "``"; infix "``" has been
  1204 renamed "`"; "univalent" has been renamed "single_valued";
  1205 
  1206 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1207 operation;
  1208 
  1209 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1210 
  1211 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1212 
  1213 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1214 consequence, it is no longer monotonic wrt. the local goal context
  1215 (which is now passed through the inductive cases);
  1216 
  1217 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1218 \<gg> to \<ggreater>;
  1219 
  1220 
  1221 *** Document preparation ***
  1222 
  1223 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1224 available: are "it" for near math-mode best-style output, "sl" for
  1225 slanted text style, and "tt" for plain type-writer; if no
  1226 \isabellestyle command is given, output is according to slanted
  1227 type-writer);
  1228 
  1229 * support sub/super scripts (for single symbols only), input syntax is
  1230 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1231 
  1232 * some more standard symbols; see Appendix A of the system manual for
  1233 the complete list of symbols defined in isabellesym.sty;
  1234 
  1235 * improved isabelle style files; more abstract symbol implementation
  1236 (should now use \isamath{...} and \isatext{...} in custom symbol
  1237 definitions);
  1238 
  1239 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1240 state; Note that presentation of goal states does not conform to
  1241 actual human-readable proof documents.  Please do not include goal
  1242 states into document output unless you really know what you are doing!
  1243 
  1244 * proper indentation of antiquoted output with proportional LaTeX
  1245 fonts;
  1246 
  1247 * no_document ML operator temporarily disables LaTeX document
  1248 generation;
  1249 
  1250 * isatool unsymbolize tunes sources for plain ASCII communication;
  1251 
  1252 
  1253 *** Isar ***
  1254 
  1255 * Pure: Isar now suffers initial goal statements to contain unbound
  1256 schematic variables (this does not conform to actual readable proof
  1257 documents, due to unpredictable outcome and non-compositional proof
  1258 checking); users who know what they are doing may use schematic goals
  1259 for Prolog-style synthesis of proven results;
  1260 
  1261 * Pure: assumption method (an implicit finishing) now handles actual
  1262 rules as well;
  1263 
  1264 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1265 initial goal, declare "that" only as Pure intro (only for single
  1266 steps); the "that" rule assumption may now be involved in implicit
  1267 finishing, thus ".." becomes a feasible for trivial obtains;
  1268 
  1269 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1270 instance proofs may be performed by "..";
  1271 
  1272 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1273 statements as well;
  1274 
  1275 * Pure: more robust selection of calculational rules;
  1276 
  1277 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1278 rule (as well as the assumption rule);
  1279 
  1280 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1281 lemmas, using the graph browser tool;
  1282 
  1283 * Pure: predict failure of "show" in interactive mode;
  1284 
  1285 * Pure: 'thms_containing' now takes actual terms as arguments;
  1286 
  1287 * HOL: improved method 'induct' --- now handles non-atomic goals
  1288 (potential INCOMPATIBILITY); tuned error handling;
  1289 
  1290 * HOL: cases and induct rules now provide explicit hints about the
  1291 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1292 any remaining facts are inserted into the goal verbatim;
  1293 
  1294 * HOL: local contexts (aka cases) may now contain term bindings as
  1295 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1296 the result to be shown in each case;
  1297 
  1298 * HOL: added 'recdef_tc' command;
  1299 
  1300 * isatool convert assists in eliminating legacy ML scripts;
  1301 
  1302 
  1303 *** HOL ***
  1304 
  1305 * HOL/Library: a collection of generic theories to be used together
  1306 with main HOL; the theory loader path already includes this directory
  1307 by default; the following existing theories have been moved here:
  1308 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1309 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1310 
  1311 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1312 modelling and verification task performed in Isabelle/HOL +
  1313 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1314 
  1315 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1316 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1317 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1318 'domain', this makes the theory consistent with mathematical
  1319 literature;
  1320 
  1321 * HOL basics: added overloaded operations "inverse" and "divide"
  1322 (infix "/"), syntax for generic "abs" operation, generic summation
  1323 operator \<Sum>;
  1324 
  1325 * HOL/typedef: simplified package, provide more useful rules (see also
  1326 HOL/subset.thy);
  1327 
  1328 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1329 now expressed as a proper nested rule (old-style tactic scripts may
  1330 require atomize_strip_tac to cope with non-atomic premises);
  1331 
  1332 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1333 to "split_conv" (old name still available for compatibility);
  1334 
  1335 * HOL: improved concrete syntax for strings (e.g. allows translation
  1336 rules with string literals);
  1337 
  1338 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1339  and Fleuriot's mechanization of analysis, including the transcendental
  1340  functions for the reals;
  1341 
  1342 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1343 
  1344 
  1345 *** CTT ***
  1346 
  1347 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1348 "lam" is displayed as TWO lambda-symbols
  1349 
  1350 * CTT: theory Main now available, containing everything (that is, Bool
  1351 and Arith);
  1352 
  1353 
  1354 *** General ***
  1355 
  1356 * Pure: the Simplifier has been implemented properly as a derived rule
  1357 outside of the actual kernel (at last!); the overall performance
  1358 penalty in practical applications is about 50%, while reliability of
  1359 the Isabelle inference kernel has been greatly improved;
  1360 
  1361 * print modes "brackets" and "no_brackets" control output of nested =>
  1362 (types) and ==> (props); the default behaviour is "brackets";
  1363 
  1364 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1365 as assumptions as well;
  1366 
  1367 * system: support Poly/ML 4.0;
  1368 
  1369 * system: isatool install handles KDE version 1 or 2;
  1370 
  1371 
  1372 
  1373 New in Isabelle99-1 (October 2000)
  1374 ----------------------------------
  1375 
  1376 *** Overview of INCOMPATIBILITIES ***
  1377 
  1378 * HOL: simplification of natural numbers is much changed; to partly
  1379 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1380 issue the following ML commands:
  1381 
  1382   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1383   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1384 
  1385 * HOL: simplification no longer dives into case-expressions; this is
  1386 controlled by "t.weak_case_cong" for each datatype t;
  1387 
  1388 * HOL: nat_less_induct renamed to less_induct;
  1389 
  1390 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1391 fixsome to patch .thy and .ML sources automatically;
  1392 
  1393   select_equality  -> some_equality
  1394   select_eq_Ex     -> some_eq_ex
  1395   selectI2EX       -> someI2_ex
  1396   selectI2         -> someI2
  1397   selectI          -> someI
  1398   select1_equality -> some1_equality
  1399   Eps_sym_eq       -> some_sym_eq_trivial
  1400   Eps_eq           -> some_eq_trivial
  1401 
  1402 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1403 
  1404 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1405 instead);
  1406 
  1407 * HOL: the recursion equations generated by 'recdef' are now called
  1408 f.simps instead of f.rules;
  1409 
  1410 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1411 
  1412 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1413 sometimes be needed;
  1414 
  1415 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1416 
  1417 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1418 
  1419 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1420 product is now "<*>" instead of "Times"; the lexicographic product is
  1421 now "<*lex*>" instead of "**";
  1422 
  1423 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1424 of main HOL, but was unused); better use HOL's datatype package;
  1425 
  1426 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1427 the old syntax may be recovered as follows:
  1428 
  1429   syntax (symbols)
  1430     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1431       (infixl "\\<oplus>" 100)
  1432 
  1433 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1434 
  1435 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1436 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1437 internally;
  1438 
  1439 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1440 changed from A/r to A//r;
  1441 
  1442 * ZF: new treatment of arithmetic (nat & int) may break some old
  1443 proofs;
  1444 
  1445 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1446 rulify -> rule_format, elimify -> elim_format, ...);
  1447 
  1448 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1449 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1450 should have to change intro!! to intro? only); replaced "delrule" by
  1451 "rule del";
  1452 
  1453 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1454 
  1455 * Provers: strengthened force_tac by using new first_best_tac;
  1456 
  1457 * LaTeX document preparation: several changes of isabelle.sty (see
  1458 lib/texinputs);
  1459 
  1460 
  1461 *** Document preparation ***
  1462 
  1463 * formal comments (text blocks etc.) in new-style theories may now
  1464 contain antiquotations of thm/prop/term/typ/text to be presented
  1465 according to latex print mode; concrete syntax is like this:
  1466 @{term[show_types] "f(x) = a + x"};
  1467 
  1468 * isatool mkdir provides easy setup of Isabelle session directories,
  1469 including proper document sources;
  1470 
  1471 * generated LaTeX sources are now deleted after successful run
  1472 (isatool document -c); may retain a copy somewhere else via -D option
  1473 of isatool usedir;
  1474 
  1475 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1476 style files, achieving self-contained LaTeX sources and simplifying
  1477 LaTeX debugging;
  1478 
  1479 * old-style theories now produce (crude) LaTeX output as well;
  1480 
  1481 * browser info session directories are now self-contained (may be put
  1482 on WWW server seperately); improved graphs of nested sessions; removed
  1483 graph for 'all sessions';
  1484 
  1485 * several improvements in isabelle style files; \isabellestyle{it}
  1486 produces fake math mode output; \isamarkupheader is now \section by
  1487 default; see lib/texinputs/isabelle.sty etc.;
  1488 
  1489 
  1490 *** Isar ***
  1491 
  1492 * Isar/Pure: local results and corresponding term bindings are now
  1493 subject to Hindley-Milner polymorphism (similar to ML); this
  1494 accommodates incremental type-inference very nicely;
  1495 
  1496 * Isar/Pure: new derived language element 'obtain' supports
  1497 generalized existence reasoning;
  1498 
  1499 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1500 support accumulation of results, without applying any rules yet;
  1501 useful to collect intermediate results without explicit name
  1502 references, and for use with transitivity rules with more than 2
  1503 premises;
  1504 
  1505 * Isar/Pure: scalable support for case-analysis type proofs: new
  1506 'case' language element refers to local contexts symbolically, as
  1507 produced by certain proof methods; internally, case names are attached
  1508 to theorems as "tags";
  1509 
  1510 * Isar/Pure: theory command 'hide' removes declarations from
  1511 class/type/const name spaces;
  1512 
  1513 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1514 indicate potential overloading;
  1515 
  1516 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1517 
  1518 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1519 "{a,b,c}" instead of {a,b,c};
  1520 
  1521 * Isar/Pure now provides its own version of intro/elim/dest
  1522 attributes; useful for building new logics, but beware of confusion
  1523 with the version in Provers/classical;
  1524 
  1525 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1526 case name 'antecedent';
  1527 
  1528 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1529 to the current context is now done automatically);
  1530 
  1531 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1532 for definining proof methods in ML;
  1533 
  1534 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1535 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1536 most cases, one should have to change intro!! to intro? only);
  1537 replaced "delrule" by "rule del";
  1538 
  1539 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1540 'symmetric' attribute (the latter supercedes [RS sym]);
  1541 
  1542 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1543 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1544 well (including splits);
  1545 
  1546 * Isar/Provers: Simplifier and Classical methods now support all kind
  1547 of modifiers used in the past, including 'cong', 'iff', etc.
  1548 
  1549 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1550 of Simplifier and Classical reasoner);
  1551 
  1552 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1553 now support named cases; major packages (inductive, datatype, primrec,
  1554 recdef) support case names and properly name parameters;
  1555 
  1556 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1557 monotonicity conditions are extracted to be proven at end of
  1558 calculations;
  1559 
  1560 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1561 method anyway;
  1562 
  1563 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1564 split_if split_if_asm; datatype package provides theorems foo.splits =
  1565 foo.split foo.split_asm for each datatype;
  1566 
  1567 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1568 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1569 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1570 use "(cases (simplified))" method in proper proof texts);
  1571 
  1572 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1573 
  1574 * Isar: names of theorems etc. may be natural numbers as well;
  1575 
  1576 * Isar: 'pr' command: optional arguments for goals_limit and
  1577 ProofContext.prems_limit; no longer prints theory contexts, but only
  1578 proof states;
  1579 
  1580 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1581 additional print modes to be specified; e.g. "pr(latex)" will print
  1582 proof state according to the Isabelle LaTeX style;
  1583 
  1584 * Isar: improved support for emulating tactic scripts, including proof
  1585 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1586 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1587 (for HOL datatypes);
  1588 
  1589 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1590 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1591 'proof method scripts' have to be in depth-first order;
  1592 
  1593 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1594 
  1595 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1596 should instead use individual commands for printing items
  1597 (print_commands, print_methods etc.);
  1598 
  1599 * Isar: added 'nothing' --- the empty list of theorems;
  1600 
  1601 
  1602 *** HOL ***
  1603 
  1604 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1605 corresponding virtual machine and a specification of its bytecode
  1606 verifier and a lightweight bytecode verifier, including proofs of
  1607 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1608 Cornelia Pusch (see also the homepage of project Bali at
  1609 http://isabelle.in.tum.de/Bali/);
  1610 
  1611 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1612 Clemens Ballarin;
  1613 
  1614 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1615 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1616 Rasmussen;
  1617 
  1618 * HOL/Lattice: fundamental concepts of lattice theory and order
  1619 structures, including duals, properties of bounds versus algebraic
  1620 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1621 Theorem for complete lattices etc.; may also serve as a demonstration
  1622 for abstract algebraic reasoning using axiomatic type classes, and
  1623 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1624 
  1625 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1626 von Oheimb;
  1627 
  1628 * HOL/IMPP: extension of IMP with local variables and mutually
  1629 recursive procedures, by David von Oheimb;
  1630 
  1631 * HOL/Lambda: converted into new-style theory and document;
  1632 
  1633 * HOL/ex/Multiquote: example of multiple nested quotations and
  1634 anti-quotations -- basically a generalized version of de-Bruijn
  1635 representation; very useful in avoiding lifting of operations;
  1636 
  1637 * HOL/record: added general record equality rule to simpset; fixed
  1638 select-update simplification procedure to handle extended records as
  1639 well; admit "r" as field name;
  1640 
  1641 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1642 other numeric types and also as the identity of groups, rings, etc.;
  1643 
  1644 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1645 Types nat and int belong to this axclass;
  1646 
  1647 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1648    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1649    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1650   two terms #m*u and #n*u are replaced by #(m+n)*u
  1651     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1652   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1653     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1654 
  1655 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1656 powerful prover for predicate logic but knows nothing of clasets; see
  1657 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1658 
  1659 * HOL: new version of "case_tac" subsumes both boolean case split and
  1660 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1661 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1662 
  1663 * HOL: simplification no longer dives into case-expressions: only the
  1664 selector expression is simplified, but not the remaining arms; to
  1665 enable full simplification of case-expressions for datatype t, you may
  1666 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1667 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1668 
  1669 * HOL/recdef: the recursion equations generated by 'recdef' for
  1670 function 'f' are now called f.simps instead of f.rules; if all
  1671 termination conditions are proved automatically, these simplification
  1672 rules are added to the simpset, as in primrec; rules may be named
  1673 individually as well, resulting in a separate list of theorems for
  1674 each equation;
  1675 
  1676 * HOL/While is a new theory that provides a while-combinator. It
  1677 permits the definition of tail-recursive functions without the
  1678 provision of a termination measure. The latter is necessary once the
  1679 invariant proof rule for while is applied.
  1680 
  1681 * HOL: new (overloaded) notation for the set of elements below/above
  1682 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1683 
  1684 * HOL: theorems impI, allI, ballI bound as "strip";
  1685 
  1686 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1687 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1688 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1689 
  1690 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1691 
  1692 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1693 main HOL, but was unused);
  1694 
  1695 * HOL: fewer consts declared as global (e.g. have to refer to
  1696 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1697 
  1698 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1699 in case of overlap with user translations (e.g. judgements over
  1700 tuples); (note that the underlying logical represenation is still
  1701 bogus);
  1702 
  1703 
  1704 *** ZF ***
  1705 
  1706 * ZF: simplification automatically cancels common terms in arithmetic
  1707 expressions over nat and int;
  1708 
  1709 * ZF: new treatment of nat to minimize type-checking: all operators
  1710 coerce their operands to a natural number using the function natify,
  1711 making the algebraic laws unconditional;
  1712 
  1713 * ZF: as above, for int: operators coerce their operands to an integer
  1714 using the function intify;
  1715 
  1716 * ZF: the integer library now contains many of the usual laws for the
  1717 orderings, including $<=, and monotonicity laws for $+ and $*;
  1718 
  1719 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1720 simplification;
  1721 
  1722 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1723 to the simplifier and classical reasoner simultaneously;
  1724 
  1725 
  1726 *** General ***
  1727 
  1728 * Provers: blast_tac now handles actual object-logic rules as
  1729 assumptions; note that auto_tac uses blast_tac internally as well;
  1730 
  1731 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1732 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1733 
  1734 * Provers: delrules now handles destruct rules as well (no longer need
  1735 explicit make_elim);
  1736 
  1737 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1738   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1739 use instead the strong form,
  1740   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1741 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1742 from destruct-rules;
  1743 
  1744 * Provers: Simplifier.easy_setup provides a fast path to basic
  1745 Simplifier setup for new object-logics;
  1746 
  1747 * Pure: AST translation rules no longer require constant head on LHS;
  1748 
  1749 * Pure: improved name spaces: ambiguous output is qualified; support
  1750 for hiding of names;
  1751 
  1752 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1753 XSYMBOL_HOME; no longer need to do manual configuration in most
  1754 situations;
  1755 
  1756 * system: compression of ML heaps images may now be controlled via -c
  1757 option of isabelle and isatool usedir (currently only observed by
  1758 Poly/ML);
  1759 
  1760 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1761 useful for remote X11);
  1762 
  1763 * system: provide TAGS file for Isabelle sources;
  1764 
  1765 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1766 order;
  1767 
  1768 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1769 timing flag supersedes proof_timing and Toplevel.trace;
  1770 
  1771 * ML: new combinators |>> and |>>> for incremental transformations
  1772 with secondary results (e.g. certain theory extensions):
  1773 
  1774 * ML: PureThy.add_defs gets additional argument to indicate potential
  1775 overloading (usually false);
  1776 
  1777 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1778 results;
  1779 
  1780 
  1781 
  1782 New in Isabelle99 (October 1999)
  1783 --------------------------------
  1784 
  1785 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1786 
  1787 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1788 are no longer simplified.  (This allows the simplifier to unfold recursive
  1789 functional programs.)  To restore the old behaviour, declare
  1790 
  1791     Delcongs [if_weak_cong];
  1792 
  1793 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1794 complement;
  1795 
  1796 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1797 
  1798 * HOL/datatype: mutual_induct_tac no longer exists --
  1799   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1800 
  1801 * HOL/typedef: fixed type inference for representing set; type
  1802 arguments now have to occur explicitly on the rhs as type constraints;
  1803 
  1804 * ZF: The con_defs part of an inductive definition may no longer refer
  1805 to constants declared in the same theory;
  1806 
  1807 * HOL, ZF: the function mk_cases, generated by the inductive
  1808 definition package, has lost an argument.  To simplify its result, it
  1809 uses the default simpset instead of a supplied list of theorems.
  1810 
  1811 * HOL/List: the constructors of type list are now Nil and Cons;
  1812 
  1813 * Simplifier: the type of the infix ML functions
  1814         setSSolver addSSolver setSolver addSolver
  1815 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1816 for packaging solvers. A solver is created via
  1817         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1818 where the string argument is only a comment.
  1819 
  1820 
  1821 *** Proof tools ***
  1822 
  1823 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1824 decision procedure for linear arithmetic. Currently it is used for
  1825 types `nat', `int', and `real' in HOL (see below); it can, should and
  1826 will be instantiated for other types and logics as well.
  1827 
  1828 * The simplifier now accepts rewrite rules with flexible heads, eg
  1829      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1830   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1831   matching.
  1832 
  1833 
  1834 *** General ***
  1835 
  1836 * New Isabelle/Isar subsystem provides an alternative to traditional
  1837 tactical theorem proving; together with the ProofGeneral/isar user
  1838 interface it offers an interactive environment for developing human
  1839 readable proof documents (Isar == Intelligible semi-automated
  1840 reasoning); for further information see isatool doc isar-ref,
  1841 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1842 
  1843 * improved and simplified presentation of theories: better HTML markup
  1844 (including colors), graph views in several sizes; isatool usedir now
  1845 provides a proper interface for user theories (via -P option); actual
  1846 document preparation based on (PDF)LaTeX is available as well (for
  1847 new-style theories only); see isatool doc system for more information;
  1848 
  1849 * native support for Proof General, both for classic Isabelle and
  1850 Isabelle/Isar;
  1851 
  1852 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1853 using the graph browser tool;
  1854 
  1855 * Isabelle manuals now also available as PDF;
  1856 
  1857 * theory loader rewritten from scratch (may not be fully
  1858 bug-compatible); old loadpath variable has been replaced by show_path,
  1859 add_path, del_path, reset_path functions; new operations such as
  1860 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1861 isatool doc ref);
  1862 
  1863 * improved isatool install: option -k creates KDE application icon,
  1864 option -p DIR installs standalone binaries;
  1865 
  1866 * added ML_PLATFORM setting (useful for cross-platform installations);
  1867 more robust handling of platform specific ML images for SML/NJ;
  1868 
  1869 * the settings environment is now statically scoped, i.e. it is never
  1870 created again in sub-processes invoked from isabelle, isatool, or
  1871 Isabelle;
  1872 
  1873 * path element specification '~~' refers to '$ISABELLE_HOME';
  1874 
  1875 * in locales, the "assumes" and "defines" parts may be omitted if
  1876 empty;
  1877 
  1878 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1879 long arrows);
  1880 
  1881 * new print_mode "HTML";
  1882 
  1883 * new flag show_tags controls display of tags of theorems (which are
  1884 basically just comments that may be attached by some tools);
  1885 
  1886 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1887 mode and goal output format:
  1888 
  1889 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1890 244c244
  1891 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1892 ---
  1893 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1894 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1895 181c181
  1896 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1897 ---
  1898 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1899 
  1900 * function bind_thms stores lists of theorems (cf. bind_thm);
  1901 
  1902 * new shorthand tactics ftac, eatac, datac, fatac;
  1903 
  1904 * qed (and friends) now accept "" as result name; in that case the
  1905 theorem is not stored, but proper checks and presentation of the
  1906 result still apply;
  1907 
  1908 * theorem database now also indexes constants "Trueprop", "all",
  1909 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1910 
  1911 
  1912 *** HOL ***
  1913 
  1914 ** HOL arithmetic **
  1915 
  1916 * There are now decision procedures for linear arithmetic over nat and
  1917 int:
  1918 
  1919 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1920 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1921 are treated as atomic; subformulae not involving type `nat' or `int'
  1922 are ignored; quantified subformulae are ignored unless they are
  1923 positive universal or negative existential. The tactic has to be
  1924 invoked by hand and can be a little bit slow. In particular, the
  1925 running time is exponential in the number of occurrences of `min' and
  1926 `max', and `-' on `nat'.
  1927 
  1928 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1929 (negated) (in)equalities among the premises and the conclusion into
  1930 account (i.e. no compound formulae) and does not know about `min' and
  1931 `max', and `-' on `nat'. It is fast and is used automatically by the
  1932 simplifier.
  1933 
  1934 NB: At the moment, these decision procedures do not cope with mixed
  1935 nat/int formulae where the two parts interact, such as `m < n ==>
  1936 int(m) < int(n)'.
  1937 
  1938 * HOL/Numeral provides a generic theory of numerals (encoded
  1939 efficiently as bit strings); setup for types nat/int/real is in place;
  1940 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1941 int, existing theories and proof scripts may require a few additional
  1942 type constraints;
  1943 
  1944 * integer division and remainder can now be performed on constant
  1945 arguments;
  1946 
  1947 * many properties of integer multiplication, division and remainder
  1948 are now available;
  1949 
  1950 * An interface to the Stanford Validity Checker (SVC) is available through the
  1951 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1952 are proved automatically.  SVC must be installed separately, and its results
  1953 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  1954 invocation of the underlying oracle).  For SVC see
  1955   http://verify.stanford.edu/SVC
  1956 
  1957 * IsaMakefile: the HOL-Real target now builds an actual image;
  1958 
  1959 
  1960 ** HOL misc **
  1961 
  1962 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  1963 (in Isabelle/Isar) -- by Gertrud Bauer;
  1964 
  1965 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  1966 analysis for assembly languages with subtypes;
  1967 
  1968 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  1969 -- avoids syntactic ambiguities and treats state, transition, and
  1970 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  1971 changed syntax and (many) tactics;
  1972 
  1973 * HOL/inductive: Now also handles more general introduction rules such
  1974   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  1975   theorems are now maintained within the theory (maintained via the
  1976   "mono" attribute);
  1977 
  1978 * HOL/datatype: Now also handles arbitrarily branching datatypes
  1979   (using function types) such as
  1980 
  1981   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  1982 
  1983 * HOL/record: record_simproc (part of the default simpset) takes care
  1984 of selectors applied to updated records; record_split_tac is no longer
  1985 part of the default claset; update_defs may now be removed from the
  1986 simpset in many cases; COMPATIBILITY: old behavior achieved by
  1987 
  1988   claset_ref () := claset() addSWrapper record_split_wrapper;
  1989   Delsimprocs [record_simproc]
  1990 
  1991 * HOL/typedef: fixed type inference for representing set; type
  1992 arguments now have to occur explicitly on the rhs as type constraints;
  1993 
  1994 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  1995 names rather than an ML expression;
  1996 
  1997 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  1998 supplied later.  Program schemes can be defined, such as
  1999     "While B C s = (if B s then While B C (C s) else s)"
  2000 where the well-founded relation can be chosen after B and C have been given.
  2001 
  2002 * HOL/List: the constructors of type list are now Nil and Cons;
  2003 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2004 course, ML tools referring to List.list.op # etc. have to be adapted;
  2005 
  2006 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2007 disabled by default; run isabelle with option -m HOL to get back to
  2008 the original Gordon/HOL-style output;
  2009 
  2010 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2011 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2012 
  2013 * HOL basic syntax simplified (more orthogonal): all variants of
  2014 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2015 Eps operator is provided as well: "SOME x. P[x]";
  2016 
  2017 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2018 
  2019 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2020 thus available for user theories;
  2021 
  2022 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2023 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2024 time;
  2025 
  2026 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2027 several times and then mp;
  2028 
  2029 
  2030 *** LK ***
  2031 
  2032 * the notation <<...>> is now available as a notation for sequences of
  2033 formulas;
  2034 
  2035 * the simplifier is now installed
  2036 
  2037 * the axiom system has been generalized (thanks to Soren Heilmann)
  2038 
  2039 * the classical reasoner now has a default rule database
  2040 
  2041 
  2042 *** ZF ***
  2043 
  2044 * new primrec section allows primitive recursive functions to be given
  2045 directly (as in HOL) over datatypes and the natural numbers;
  2046 
  2047 * new tactics induct_tac and exhaust_tac for induction (or case
  2048 analysis) over datatypes and the natural numbers;
  2049 
  2050 * the datatype declaration of type T now defines the recursor T_rec;
  2051 
  2052 * simplification automatically does freeness reasoning for datatype
  2053 constructors;
  2054 
  2055 * automatic type-inference, with AddTCs command to insert new
  2056 type-checking rules;
  2057 
  2058 * datatype introduction rules are now added as Safe Introduction rules
  2059 to the claset;
  2060 
  2061 * the syntax "if P then x else y" is now available in addition to
  2062 if(P,x,y);
  2063 
  2064 
  2065 *** Internal programming interfaces ***
  2066 
  2067 * tuned simplifier trace output; new flag debug_simp;
  2068 
  2069 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2070 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2071 
  2072 * AxClass.axclass_tac lost the theory argument;
  2073 
  2074 * tuned current_goals_markers semantics: begin / end goal avoids
  2075 printing empty lines;
  2076 
  2077 * removed prs and prs_fn hook, which was broken because it did not
  2078 include \n in its semantics, forcing writeln to add one
  2079 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2080 string -> unit if you really want to output text without newline;
  2081 
  2082 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2083 plain output, interface builders may have to enable 'isabelle_font'
  2084 mode to get Isabelle font glyphs as before;
  2085 
  2086 * refined token_translation interface; INCOMPATIBILITY: output length
  2087 now of type real instead of int;
  2088 
  2089 * theory loader actions may be traced via new ThyInfo.add_hook
  2090 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2091 your own database of information attached to *whole* theories -- as
  2092 opposed to intra-theory data slots offered via TheoryDataFun;
  2093 
  2094 * proper handling of dangling sort hypotheses (at last!);
  2095 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2096 extra sort hypotheses that can be witnessed from the type signature;
  2097 the force_strip_shyps flag is gone, any remaining shyps are simply
  2098 left in the theorem (with a warning issued by strip_shyps_warning);
  2099 
  2100 
  2101 
  2102 New in Isabelle98-1 (October 1998)
  2103 ----------------------------------
  2104 
  2105 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2106 
  2107 * several changes of automated proof tools;
  2108 
  2109 * HOL: major changes to the inductive and datatype packages, including
  2110 some minor incompatibilities of theory syntax;
  2111 
  2112 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2113 called `inj_on';
  2114 
  2115 * HOL: removed duplicate thms in Arith:
  2116   less_imp_add_less  should be replaced by  trans_less_add1
  2117   le_imp_add_le      should be replaced by  trans_le_add1
  2118 
  2119 * HOL: unary minus is now overloaded (new type constraints may be
  2120 required);
  2121 
  2122 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2123 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2124 now taken as an integer constant.
  2125 
  2126 * Pure: ML function 'theory_of' renamed to 'theory';
  2127 
  2128 
  2129 *** Proof tools ***
  2130 
  2131 * Simplifier:
  2132   1. Asm_full_simp_tac is now more aggressive.
  2133      1. It will sometimes reorient premises if that increases their power to
  2134         simplify.
  2135      2. It does no longer proceed strictly from left to right but may also
  2136         rotate premises to achieve further simplification.
  2137      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2138      old Asm_full_simp_tac in that it does not rotate premises.
  2139   2. The simplifier now knows a little bit about nat-arithmetic.
  2140 
  2141 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2142 allows for selected deletion of wrappers, by introduction of names for
  2143 wrapper functionals.  This implies that addbefore, addSbefore,
  2144 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2145 and that adding two tactics with the same name overwrites the first
  2146 one (emitting a warning).
  2147   type wrapper = (int -> tactic) -> (int -> tactic)
  2148   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2149   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2150   delWrapper, delSWrapper: claset *  string            -> claset
  2151   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2152 
  2153 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2154 semantics; addbefore now affects only the unsafe part of step_tac
  2155 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2156 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2157 by Force_tac;
  2158 
  2159 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2160 compWrapper; added safe wrapper (and access functions for it);
  2161 
  2162 * HOL/split_all_tac is now much faster and fails if there is nothing
  2163 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2164 and the names of the automatically generated variables have changed.
  2165 split_all_tac has moved within claset() from unsafe wrappers to safe
  2166 wrappers, which means that !!-bound variables are split much more
  2167 aggressively, and safe_tac and clarify_tac now split such variables.
  2168 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2169 Note: the same holds for record_split_tac, which does the job of
  2170 split_all_tac for record fields.
  2171 
  2172 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2173 permanently to the default simpset using Addsplits just like
  2174 Addsimps. They can be removed via Delsplits just like
  2175 Delsimps. Lower-case versions are also available.
  2176 
  2177 * HOL/Simplifier: The rule split_if is now part of the default
  2178 simpset. This means that the simplifier will eliminate all occurrences
  2179 of if-then-else in the conclusion of a goal. To prevent this, you can
  2180 either remove split_if completely from the default simpset by
  2181 `Delsplits [split_if]' or remove it in a specific call of the
  2182 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2183 other case splitting rules to/from the default simpset: every datatype
  2184 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2185 t is the name of the datatype).
  2186 
  2187 * Classical reasoner / Simplifier combination: new force_tac (and
  2188 derivatives Force_tac, force) combines rewriting and classical
  2189 reasoning (and whatever other tools) similarly to auto_tac, but is
  2190 aimed to solve the given subgoal completely.
  2191 
  2192 
  2193 *** General ***
  2194 
  2195 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2196 and `goalw': the theory is no longer needed as an explicit argument -
  2197 the current theory context is used; assumptions are no longer returned
  2198 at the ML-level unless one of them starts with ==> or !!; it is
  2199 recommended to convert to these new commands using isatool fixgoal
  2200 (backup your sources first!);
  2201 
  2202 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2203 the current theory context, and 'theory' to lookup stored theories;
  2204 
  2205 * new theory section 'locale' for declaring constants, assumptions and
  2206 definitions that have local scope;
  2207 
  2208 * new theory section 'nonterminals' for purely syntactic types;
  2209 
  2210 * new theory section 'setup' for generic ML setup functions
  2211 (e.g. package initialization);
  2212 
  2213 * the distribution now includes Isabelle icons: see
  2214 lib/logo/isabelle-{small,tiny}.xpm;
  2215 
  2216 * isatool install - install binaries with absolute references to
  2217 ISABELLE_HOME/bin;
  2218 
  2219 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2220 
  2221 * print mode 'emacs' reserved for Isamode;
  2222 
  2223 * support multiple print (ast) translations per constant name;
  2224 
  2225 * theorems involving oracles are now printed with a suffixed [!];
  2226 
  2227 
  2228 *** HOL ***
  2229 
  2230 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2231 
  2232 * HOL/inductive package reorganized and improved: now supports mutual
  2233 definitions such as
  2234 
  2235   inductive EVEN ODD
  2236     intrs
  2237       null "0 : EVEN"
  2238       oddI "n : EVEN ==> Suc n : ODD"
  2239       evenI "n : ODD ==> Suc n : EVEN"
  2240 
  2241 new theorem list "elims" contains an elimination rule for each of the
  2242 recursive sets; inductive definitions now handle disjunctive premises
  2243 correctly (also ZF);
  2244 
  2245 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2246 "mutual_induct" no longer exists - the induction rule is always
  2247 contained in "induct";
  2248 
  2249 
  2250 * HOL/datatype package re-implemented and greatly improved: now
  2251 supports mutually recursive datatypes such as
  2252 
  2253   datatype
  2254     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2255             | SUM ('a aexp) ('a aexp)
  2256             | DIFF ('a aexp) ('a aexp)
  2257             | NUM 'a
  2258   and
  2259     'a bexp = LESS ('a aexp) ('a aexp)
  2260             | AND ('a bexp) ('a bexp)
  2261             | OR ('a bexp) ('a bexp)
  2262 
  2263 as well as indirectly recursive datatypes such as
  2264 
  2265   datatype
  2266     ('a, 'b) term = Var 'a
  2267                   | App 'b ((('a, 'b) term) list)
  2268 
  2269 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2270 induction on mutually / indirectly recursive datatypes.
  2271 
  2272 Primrec equations are now stored in theory and can be accessed via
  2273 <function_name>.simps.
  2274 
  2275 INCOMPATIBILITIES:
  2276 
  2277   - Theories using datatypes must now have theory Datatype as an
  2278     ancestor.
  2279   - The specific <typename>.induct_tac no longer exists - use the
  2280     generic induct_tac instead.
  2281   - natE has been renamed to nat.exhaust - use exhaust_tac
  2282     instead of res_inst_tac ... natE. Note that the variable
  2283     names in nat.exhaust differ from the names in natE, this
  2284     may cause some "fragile" proofs to fail.
  2285   - The theorems split_<typename>_case and split_<typename>_case_asm
  2286     have been renamed to <typename>.split and <typename>.split_asm.
  2287   - Since default sorts of type variables are now handled correctly,
  2288     some datatype definitions may have to be annotated with explicit
  2289     sort constraints.
  2290   - Primrec definitions no longer require function name and type
  2291     of recursive argument.
  2292 
  2293 Consider using isatool fixdatatype to adapt your theories and proof
  2294 scripts to the new package (backup your sources first!).
  2295 
  2296 
  2297 * HOL/record package: considerably improved implementation; now
  2298 includes concrete syntax for record types, terms, updates; theorems
  2299 for surjective pairing and splitting !!-bound record variables; proof
  2300 support is as follows:
  2301 
  2302   1) standard conversions (selectors or updates applied to record
  2303 constructor terms) are part of the standard simpset;
  2304 
  2305   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2306 made part of standard simpset and claset via addIffs;
  2307 
  2308   3) a tactic for record field splitting (record_split_tac) is part of
  2309 the standard claset (addSWrapper);
  2310 
  2311 To get a better idea about these rules you may retrieve them via
  2312 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2313 the name of your record type.
  2314 
  2315 The split tactic 3) conceptually simplifies by the following rule:
  2316 
  2317   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2318 
  2319 Thus any record variable that is bound by meta-all will automatically
  2320 blow up into some record constructor term, consequently the
  2321 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2322 solve record problems automatically.
  2323 
  2324 
  2325 * reorganized the main HOL image: HOL/Integ and String loaded by
  2326 default; theory Main includes everything;
  2327 
  2328 * automatic simplification of integer sums and comparisons, using cancellation;
  2329 
  2330 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2331 
  2332 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2333 
  2334 * many new identities for unions, intersections, set difference, etc.;
  2335 
  2336 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2337 called split_if, split_split, split_sum_case and split_nat_case (to go
  2338 with add/delsplits);
  2339 
  2340 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2341 (?x::unit) = (); this is made part of the default simpset, which COULD
  2342 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2343 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2344 unit_abs_eta_conv is added in order to counter the effect of
  2345 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2346 %u.f();
  2347 
  2348 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2349 makes more sense);
  2350 
  2351 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2352   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2353   disjointness reasoning but breaking a few old proofs.
  2354 
  2355 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2356 to 'converse' from 'inverse' (for compatibility with ZF and some
  2357 literature);
  2358 
  2359 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2360 the well-founded relation;
  2361 
  2362 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2363     Compl A.  The "Compl" syntax remains available as input syntax for this
  2364     release ONLY.
  2365 
  2366 * HOL/Update: new theory of function updates:
  2367     f(a:=b) == %x. if x=a then b else f x
  2368 may also be iterated as in f(a:=b,c:=d,...);
  2369 
  2370 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2371 
  2372 * HOL/List:
  2373   - new function list_update written xs[i:=v] that updates the i-th
  2374     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2375   - new function `upt' written [i..j(] which generates the list
  2376     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2377     bound write [i..j], which is a shorthand for [i..j+1(].
  2378   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2379 
  2380 * HOL/Arith:
  2381   - removed 'pred' (predecessor) function;
  2382   - generalized some theorems about n-1;
  2383   - many new laws about "div" and "mod";
  2384   - new laws about greatest common divisors (see theory ex/Primes);
  2385 
  2386 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2387 instead of "inverse";
  2388 
  2389 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2390   of the multiset ordering;
  2391 
  2392 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2393   (not included by default);
  2394 
  2395 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2396 
  2397 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2398   programs, i.e. different program variables may have different types.
  2399 
  2400 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2401   [previously, this check worked only if the rewrite rule was unconditional]
  2402   Now rew can involve either definitions or equalities (either == or =).
  2403 
  2404 
  2405 *** ZF ***
  2406 
  2407 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2408   only the theorems proved on ZF.ML;
  2409 
  2410 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2411   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2412   disjointness reasoning but breaking a few old proofs.
  2413 
  2414 * ZF/Update: new theory of function updates
  2415     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2416   may also be iterated as in f(a:=b,c:=d,...);
  2417 
  2418 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2419 
  2420 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2421   [previously, this check worked only if the rewrite rule was unconditional]
  2422   Now rew can involve either definitions or equalities (either == or =).
  2423 
  2424 * case_tac provided for compatibility with HOL
  2425     (like the old excluded_middle_tac, but with subgoals swapped)
  2426 
  2427 
  2428 *** Internal programming interfaces ***
  2429 
  2430 * Pure: several new basic modules made available for general use, see
  2431 also src/Pure/README;
  2432 
  2433 * improved the theory data mechanism to support encapsulation (data
  2434 kind name replaced by private Object.kind, acting as authorization
  2435 key); new type-safe user interface via functor TheoryDataFun; generic
  2436 print_data function becomes basically useless;
  2437 
  2438 * removed global_names compatibility flag -- all theory declarations
  2439 are qualified by default;
  2440 
  2441 * module Pure/Syntax now offers quote / antiquote translation
  2442 functions (useful for Hoare logic etc. with implicit dependencies);
  2443 see HOL/ex/Antiquote for an example use;
  2444 
  2445 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2446 cterm -> thm;
  2447 
  2448 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2449 subgoal;
  2450 
  2451 * Display.print_goals function moved to Locale.print_goals;
  2452 
  2453 * standard print function for goals supports current_goals_markers
  2454 variable for marking begin of proof, end of proof, start of goal; the
  2455 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2456 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2457 for example;
  2458 
  2459 
  2460 
  2461 New in Isabelle98 (January 1998)
  2462 --------------------------------
  2463 
  2464 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2465 
  2466 * changed lexical syntax of terms / types: dots made part of long
  2467 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2468 
  2469 * simpset (and claset) reference variable replaced by functions
  2470 simpset / simpset_ref;
  2471 
  2472 * no longer supports theory aliases (via merge) and non-trivial
  2473 implicit merge of thms' signatures;
  2474 
  2475 * most internal names of constants changed due to qualified names;
  2476 
  2477 * changed Pure/Sequence interface (see Pure/seq.ML);
  2478 
  2479 
  2480 *** General Changes ***
  2481 
  2482 * hierachically structured name spaces (for consts, types, axms, thms
  2483 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2484 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2485 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2486 long_names for fully qualified output names; NOTE: ML programs
  2487 (special tactics, packages etc.) referring to internal names may have
  2488 to be adapted to cope with fully qualified names; in case of severe
  2489 backward campatibility problems try setting 'global_names' at compile
  2490 time to have enrything declared within a flat name space; one may also
  2491 fine tune name declarations in theories via the 'global' and 'local'
  2492 section;
  2493 
  2494 * reimplemented the implicit simpset and claset using the new anytype
  2495 data filed in signatures; references simpset:simpset ref etc. are
  2496 replaced by functions simpset:unit->simpset and
  2497 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2498 to patch your ML files accordingly;
  2499 
  2500 * HTML output now includes theory graph data for display with Java
  2501 applet or isatool browser; data generated automatically via isatool
  2502 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2503 
  2504 * defs may now be conditional; improved rewrite_goals_tac to handle
  2505 conditional equations;
  2506 
  2507 * defs now admits additional type arguments, using TYPE('a) syntax;
  2508 
  2509 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2510 creates a new theory node; implicit merge of thms' signatures is
  2511 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2512 transfer:theory->thm->thm in (rare) cases;
  2513 
  2514 * improved handling of draft signatures / theories; draft thms (and
  2515 ctyps, cterms) are automatically promoted to real ones;
  2516 
  2517 * slightly changed interfaces for oracles: admit many per theory, named
  2518 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2519 
  2520 * print_goals: optional output of const types (set show_consts and
  2521 show_types);
  2522 
  2523 * improved output of warnings (###) and errors (***);
  2524 
  2525 * subgoal_tac displays a warning if the new subgoal has type variables;
  2526 
  2527 * removed old README and Makefiles;
  2528 
  2529 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2530 
  2531 * removed obsolete init_pps and init_database;
  2532 
  2533 * deleted the obsolete tactical STATE, which was declared by
  2534     fun STATE tacfun st = tacfun st st;
  2535 
  2536 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2537 (which abbreviates $HOME);
  2538 
  2539 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2540 use isatool fixseq to adapt your ML programs (this works for fully
  2541 qualified references to the Sequence structure only!);
  2542 
  2543 * use_thy no longer requires writable current directory; it always
  2544 reloads .ML *and* .thy file, if either one is out of date;
  2545 
  2546 
  2547 *** Classical Reasoner ***
  2548 
  2549 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2550 tactics that use classical reasoning to simplify a subgoal without
  2551 splitting it into several subgoals;
  2552 
  2553 * Safe_tac: like safe_tac but uses the default claset;
  2554 
  2555 
  2556 *** Simplifier ***
  2557 
  2558 * added simplification meta rules:
  2559     (asm_)(full_)simplify: simpset -> thm -> thm;
  2560 
  2561 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2562 logics (again);
  2563 
  2564 * added prems argument to simplification procedures;
  2565 
  2566 * HOL, FOL, ZF: added infix function `addsplits':
  2567   instead of `<simpset> setloop (split_tac <thms>)'
  2568   you can simply write `<simpset> addsplits <thms>'
  2569 
  2570 
  2571 *** Syntax ***
  2572 
  2573 * TYPE('a) syntax for type reflection terms;
  2574 
  2575 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2576 
  2577 * pretty printer: changed order of mixfix annotation preference (again!);
  2578 
  2579 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2580 
  2581 
  2582 *** HOL ***
  2583 
  2584 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2585   with `addloop' of the simplifier to faciliate case splitting in premises.
  2586 
  2587 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2588 
  2589 * HOL/Auth: new protocol proofs including some for the Internet
  2590   protocol TLS;
  2591 
  2592 * HOL/Map: new theory of `maps' a la VDM;
  2593 
  2594 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2595 cancelling out common nat summands from =, <, <= (in)equalities, or
  2596 differences; simplification procedures nat_cancel_factor for
  2597 cancelling common factor from =, <, <= (in)equalities over natural
  2598 sums; nat_cancel contains both kinds of procedures, it is installed by
  2599 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2600 
  2601 * HOL/simplifier: terms of the form
  2602   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2603   are rewritten to
  2604   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2605   and those of the form
  2606   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2607   are rewritten to
  2608   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2609 
  2610 * HOL/datatype
  2611   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2612 
  2613   P(t_case f1 ... fn x) =
  2614      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2615         ...
  2616        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2617      )
  2618 
  2619   and a theorem `split_t_case_asm' of the form
  2620 
  2621   P(t_case f1 ... fn x) =
  2622     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2623         ...
  2624        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2625      )
  2626   which can be added to a simpset via `addsplits'. The existing theorems
  2627   expand_list_case and expand_option_case have been renamed to
  2628   split_list_case and split_option_case.
  2629 
  2630 * HOL/Arithmetic:
  2631   - `pred n' is automatically converted to `n-1'.
  2632     Users are strongly encouraged not to use `pred' any longer,
  2633     because it will disappear altogether at some point.
  2634   - Users are strongly encouraged to write "0 < n" rather than
  2635     "n ~= 0". Theorems and proof tools have been modified towards this
  2636     `standard'.
  2637 
  2638 * HOL/Lists:
  2639   the function "set_of_list" has been renamed "set" (and its theorems too);
  2640   the function "nth" now takes its arguments in the reverse order and
  2641   has acquired the infix notation "!" as in "xs!n".
  2642 
  2643 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2644 
  2645 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2646   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2647 
  2648 * HOL/record: extensible records with schematic structural subtyping
  2649 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2650 still lacks various theorems and concrete record syntax;
  2651 
  2652 
  2653 *** HOLCF ***
  2654 
  2655 * removed "axioms" and "generated by" sections;
  2656 
  2657 * replaced "ops" section by extended "consts" section, which is capable of
  2658   handling the continuous function space "->" directly;
  2659 
  2660 * domain package:
  2661   . proves theorems immediately and stores them in the theory,
  2662   . creates hierachical name space,
  2663   . now uses normal mixfix annotations (instead of cinfix...),
  2664   . minor changes to some names and values (for consistency),
  2665   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2666   . separator between mutual domain defs: changed "," to "and",
  2667   . improved handling of sort constraints;  now they have to
  2668     appear on the left-hand side of the equations only;
  2669 
  2670 * fixed LAM <x,y,zs>.b syntax;
  2671 
  2672 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2673 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2674 
  2675 
  2676 *** FOL and ZF ***
  2677 
  2678 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2679   with `addloop' of the simplifier to faciliate case splitting in premises.
  2680 
  2681 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2682 in HOL, they strip ALL and --> from proved theorems;
  2683 
  2684 
  2685 
  2686 New in Isabelle94-8 (May 1997)
  2687 ------------------------------
  2688 
  2689 *** General Changes ***
  2690 
  2691 * new utilities to build / run / maintain Isabelle etc. (in parts
  2692 still somewhat experimental); old Makefiles etc. still functional;
  2693 
  2694 * new 'Isabelle System Manual';
  2695 
  2696 * INSTALL text, together with ./configure and ./build scripts;
  2697 
  2698 * reimplemented type inference for greater efficiency, better error
  2699 messages and clean internal interface;
  2700 
  2701 * prlim command for dealing with lots of subgoals (an easier way of
  2702 setting goals_limit);
  2703 
  2704 
  2705 *** Syntax ***
  2706 
  2707 * supports alternative (named) syntax tables (parser and pretty
  2708 printer); internal interface is provided by add_modesyntax(_i);
  2709 
  2710 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2711 be used in conjunction with the Isabelle symbol font; uses the
  2712 "symbols" syntax table;
  2713 
  2714 * added token_translation interface (may translate name tokens in
  2715 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2716 the current print_mode); IMPORTANT: user print translation functions
  2717 are responsible for marking newly introduced bounds
  2718 (Syntax.mark_boundT);
  2719 
  2720 * token translations for modes "xterm" and "xterm_color" that display
  2721 names in bold, underline etc. or colors (which requires a color
  2722 version of xterm);
  2723 
  2724 * infixes may now be declared with names independent of their syntax;
  2725 
  2726 * added typed_print_translation (like print_translation, but may
  2727 access type of constant);
  2728 
  2729 
  2730 *** Classical Reasoner ***
  2731 
  2732 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2733 some limitations.  Blast_tac...
  2734   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2735   + ignores elimination rules that don't have the correct format
  2736         (the conclusion MUST be a formula variable)
  2737   + ignores types, which can make HOL proofs fail
  2738   + rules must not require higher-order unification, e.g. apply_type in ZF
  2739     [message "Function Var's argument not a bound variable" relates to this]
  2740   + its proof strategy is more general but can actually be slower
  2741 
  2742 * substitution with equality assumptions no longer permutes other
  2743 assumptions;
  2744 
  2745 * minor changes in semantics of addafter (now called addaltern); renamed
  2746 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2747 (and access functions for it);
  2748 
  2749 * improved combination of classical reasoner and simplifier:
  2750   + functions for handling clasimpsets
  2751   + improvement of addss: now the simplifier is called _after_ the
  2752     safe steps.
  2753   + safe variant of addss called addSss: uses safe simplifications
  2754     _during_ the safe steps. It is more complete as it allows multiple
  2755     instantiations of unknowns (e.g. with slow_tac).
  2756 
  2757 *** Simplifier ***
  2758 
  2759 * added interface for simplification procedures (functions that
  2760 produce *proven* rewrite rules on the fly, depending on current
  2761 redex);
  2762 
  2763 * ordering on terms as parameter (used for ordered rewriting);
  2764 
  2765 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2766 
  2767 * the solver is now split into a safe and an unsafe part.
  2768 This should be invisible for the normal user, except that the
  2769 functions setsolver and addsolver have been renamed to setSolver and
  2770 addSolver; added safe_asm_full_simp_tac;
  2771 
  2772 
  2773 *** HOL ***
  2774 
  2775 * a generic induction tactic `induct_tac' which works for all datatypes and
  2776 also for type `nat';
  2777 
  2778 * a generic case distinction tactic `exhaust_tac' which works for all
  2779 datatypes and also for type `nat';
  2780 
  2781 * each datatype comes with a function `size';
  2782 
  2783 * patterns in case expressions allow tuple patterns as arguments to
  2784 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2785 
  2786 * primrec now also works with type nat;
  2787 
  2788 * recdef: a new declaration form, allows general recursive functions to be
  2789 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2790 
  2791 * the constant for negation has been renamed from "not" to "Not" to
  2792 harmonize with FOL, ZF, LK, etc.;
  2793 
  2794 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2795 infinite lists;
  2796 
  2797 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2798 
  2799 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2800 problems in commutative rings, using axiomatic type classes for + and *;
  2801 
  2802 * more examples in HOL/MiniML and HOL/Auth;
  2803 
  2804 * more default rewrite rules for quantifiers, union/intersection;
  2805 
  2806 * a new constant `arbitrary == @x.False';
  2807 
  2808 * HOLCF/IOA replaces old HOL/IOA;
  2809 
  2810 * HOLCF changes: derived all rules and arities
  2811   + axiomatic type classes instead of classes
  2812   + typedef instead of faking type definitions
  2813   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2814   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2815   + eliminated the types void, one, tr
  2816   + use unit lift and bool lift (with translations) instead of one and tr
  2817   + eliminated blift from Lift3.thy (use Def instead of blift)
  2818   all eliminated rules are derived as theorems --> no visible changes ;
  2819 
  2820 
  2821 *** ZF ***
  2822 
  2823 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2824 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2825 as ZF_cs addSIs [equalityI];
  2826 
  2827 
  2828 
  2829 New in Isabelle94-7 (November 96)
  2830 ---------------------------------
  2831 
  2832 * allowing negative levels (as offsets) in prlev and choplev;
  2833 
  2834 * super-linear speedup for large simplifications;
  2835 
  2836 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2837 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2838 FAIL); can suppress it using the command Delsimps (ex_simps @
  2839 all_simps); De Morgan laws are also now included, by default;
  2840 
  2841 * improved printing of ==>  :  ~:
  2842 
  2843 * new object-logic "Sequents" adds linear logic, while replacing LK
  2844 and Modal (thanks to Sara Kalvala);
  2845 
  2846 * HOL/Auth: correctness proofs for authentication protocols;
  2847 
  2848 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2849 examples on HOL/Auth);
  2850 
  2851 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2852 the rewriter and classical reasoner simultaneously;
  2853 
  2854 * function uresult no longer returns theorems in "standard" format;
  2855 regain previous version by: val uresult = standard o uresult;
  2856 
  2857 
  2858 
  2859 New in Isabelle94-6
  2860 -------------------
  2861 
  2862 * oracles -- these establish an interface between Isabelle and trusted
  2863 external reasoners, which may deliver results as theorems;
  2864 
  2865 * proof objects (in particular record all uses of oracles);
  2866 
  2867 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2868 
  2869 * "constdefs" section in theory files;
  2870 
  2871 * "primrec" section (HOL) no longer requires names;
  2872 
  2873 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2874 
  2875 
  2876 
  2877 New in Isabelle94-5
  2878 -------------------
  2879 
  2880 * reduced space requirements;
  2881 
  2882 * automatic HTML generation from theories;
  2883 
  2884 * theory files no longer require "..." (quotes) around most types;
  2885 
  2886 * new examples, including two proofs of the Church-Rosser theorem;
  2887 
  2888 * non-curried (1994) version of HOL is no longer distributed;
  2889 
  2890 
  2891 
  2892 New in Isabelle94-4
  2893 -------------------
  2894 
  2895 * greatly reduced space requirements;
  2896 
  2897 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2898 
  2899 * searchable theorem database (see the section "Retrieving theorems" on
  2900 page 8 of the Reference Manual);
  2901 
  2902 * new examples, including Grabczewski's monumental case study of the
  2903 Axiom of Choice;
  2904 
  2905 * The previous version of HOL renamed to Old_HOL;
  2906 
  2907 * The new version of HOL (previously called CHOL) uses a curried syntax
  2908 for functions.  Application looks like f a b instead of f(a,b);
  2909 
  2910 * Mutually recursive inductive definitions finally work in HOL;
  2911 
  2912 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2913 translates to the operator "split";
  2914 
  2915 
  2916 
  2917 New in Isabelle94-3
  2918 -------------------
  2919 
  2920 * new infix operator, addss, allowing the classical reasoner to
  2921 perform simplification at each step of its search.  Example:
  2922         fast_tac (cs addss ss)
  2923 
  2924 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2925 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2926 look like (a,b) instead of <a,b>;
  2927 
  2928 * PLEASE NOTE: CHOL will eventually replace HOL!
  2929 
  2930 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2931 It translates to the operator "split".  A new theory of integers is available;
  2932 
  2933 * In ZF, integer numerals now denote two's-complement binary integers.
  2934 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2935 
  2936 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2937 of the Axiom of Choice;
  2938 
  2939 
  2940 
  2941 New in Isabelle94-2
  2942 -------------------
  2943 
  2944 * Significantly faster resolution;
  2945 
  2946 * the different sections in a .thy file can now be mixed and repeated
  2947 freely;
  2948 
  2949 * Database of theorems for FOL, HOL and ZF.  New
  2950 commands including qed, qed_goal and bind_thm store theorems in the database.
  2951 
  2952 * Simple database queries: return a named theorem (get_thm) or all theorems of
  2953 a given theory (thms_of), or find out what theory a theorem was proved in
  2954 (theory_of_thm);
  2955 
  2956 * Bugs fixed in the inductive definition and datatype packages;
  2957 
  2958 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  2959 and HOL_dup_cs obsolete;
  2960 
  2961 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  2962 have been removed;
  2963 
  2964 * Simpler definition of function space in ZF;
  2965 
  2966 * new results about cardinal and ordinal arithmetic in ZF;
  2967 
  2968 * 'subtype' facility in HOL for introducing new types as subsets of existing
  2969 types;
  2970 
  2971 
  2972 $Id$