NEWS
author berghofe
Thu Apr 21 19:12:03 2005 +0200 (2005-04-21)
changeset 15797 a63605582573
parent 15778 98af3693f6b3
child 15801 d2f5ca3c048d
permissions -rw-r--r--
- Eliminated nodup_vars check.
- Unification and matching functions now check types of term variables / sorts
of type variables when applying a substitution.
- Thm.instantiate now takes (ctyp * ctyp) list instead of (indexname * ctyp) list
as argument, to allow for proper instantiation of theorems containing
type variables with same name but different sorts.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * ML: 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 raise the exception Option.
    14 
    15 * ML: 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 basic functions are now no longer exported to the top ML
    21   level, as they are variants of standard functions.  The following
    22   suggests how one can translate existing code:
    23 
    24     the x = valOf x
    25     if_none x y = getOpt(x,y)
    26     is_some x = isSome x
    27     apsome f x = Option.map f x
    28     rev_append xs ys = List.revAppend(xs,ys)
    29     nth_elem(i,xs) = List.nth(xs,i)
    30     last_elem xs = List.last xs
    31     flat xss = List.concat xss
    32     seq fs = app fs
    33     partition P xs = List.partition P xs
    34     filter P xs = List.filter P xs
    35     mapfilter f xs = List.mapPartial f xs
    36 
    37   The final four functions, take, drop, foldl, and foldr, are somewhat
    38   more complicated (especially the semantics of take and drop differ
    39   from the standard).
    40 
    41   A simple solution to broken code is to include "open Library" at the
    42   beginning of a structure.  Everything after that will be as before.
    43 
    44 * Theory headers: the new header syntax for Isar theories is
    45 
    46   theory <name>
    47   imports <theory1> ... <theoryn>
    48   begin
    49 
    50   optionally also with a "files" section. The syntax
    51 
    52   theory <name> = <theory1> + ... + <theoryn>:
    53 
    54   will still be supported for some time but will eventually disappear.
    55   The syntax of old-style theories has not changed.
    56 
    57 * Theory loader: parent theories can now also be referred to via
    58   relative and absolute paths.
    59 
    60 * Provers/quasi.ML:  new transitivity reasoners for transitivity only
    61   and quasi orders.
    62 
    63 * Provers/trancl.ML:  new transitivity reasoner for transitive and
    64   reflexive-transitive closure of relations.
    65 
    66 * Provers/blast.ML:  new reference depth_limit to make blast's depth
    67   limit (previously hard-coded with a value of 20) user-definable.
    68 
    69 * Provers: new version of the subst method, for single-step rewriting: it now
    70   works in bound variable contexts. New is subst (asm), for rewriting an
    71   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    72   subterm than the original subst method, which is still available under the
    73   name simplesubst.
    74 
    75 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    76   More generally, erule now works even if the major premise of the elimination rule
    77   contains !! or ==>.
    78 
    79 * Pure: considerably improved version of 'constdefs' command.  Now
    80   performs automatic type-inference of declared constants; additional
    81   support for local structure declarations (cf. locales and HOL
    82   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    83   to observe strictly sequential dependencies of definitions within a
    84   single 'constdefs' section; moreover, the declared name needs to be
    85   an identifier.  If all fails, consider to fall back on 'consts' and
    86   'defs' separately.
    87 
    88 * Pure: improved indexed syntax and implicit structures.  First of
    89   all, indexed syntax provides a notational device for subscripted
    90   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    91   expressions.  Secondly, in a local context with structure
    92   declarations, number indexes \<^sub>n or the empty index (default
    93   number 1) refer to a certain fixed variable implicitly; option
    94   show_structs controls printing of implicit structures.  Typical
    95   applications of these concepts involve record types and locales.
    96 
    97 * Pure: clear separation of logical types and nonterminals, where the
    98   latter may only occur in 'syntax' specifications or type
    99   abbreviations.  Before that distinction was only partially
   100   implemented via type class "logic" vs. "{}".  Potential
   101   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
   102   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
   103   specifications may require further adaption (e.g. Cube/Base.thy).
   104 
   105 * Pure: removed obsolete type class "logic", use the top sort {}
   106   instead.  Note that non-logical types should be declared as
   107   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
   108   object-logic specifications.
   109 
   110 * Pure: command 'no_syntax' removes grammar declarations (and
   111   translations) resulting from the given syntax specification, which
   112   is interpreted in the same manner as for the 'syntax' command.
   113 
   114 * Pure: print_tac now outputs the goal through the trace channel.
   115 
   116 * Pure: reference Namespace.unique_names included.  If true the
   117   (shortest) namespace-prefix is printed to disambiguate conflicts (as
   118   yet). If false the first entry wins (as during parsing). Default
   119   value is true.
   120 
   121 * Pure: tuned internal renaming of symbolic identifiers -- attach
   122   primes instead of base 26 numbers.
   123 
   124 * Pure: new flag show_var_qmarks to control printing of leading
   125   question marks of variable names.
   126 
   127 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   128 
   129 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   130   specified in mixfix annotations as "(00...)".
   131 
   132 * Pure/Syntax: 'advanced' translation functions (parse_translation
   133   etc.) may depend on the signature of the theory context being
   134   presently used for parsing/printing, see also isar-ref manual.
   135 
   136 * Pure/Simplifier: simplification procedures may now take the current
   137   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   138   interface), which is very useful for calling the Simplifier
   139   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   140   simprocs is gone -- use prems_of_ss on the simpset instead.
   141   Moreover, the low-level mk_simproc no longer applies Logic.varify
   142   internally, to allow for use in a context of fixed variables.
   143 
   144 * Pure/Simplifier: Command "find_rewrites" takes a string and lists all
   145   equality theorems (not just those declared as simp!) whose left-hand
   146   side matches the term given via the string. In PG the command can be
   147   activated via Isabelle -> Show me -> matching rewrites.
   148 
   149 * Isar debugging: new reference Toplevel.debug; default false.
   150   Set to make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   151   
   152 * Locales:
   153   - "includes" disallowed in declaration of named locales (command "locale").
   154   - Fixed parameter management in theorem generation for goals with "includes".
   155     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   156 
   157 * Locales:  new commands for the interpretation of locale expressions
   158   in theories (interpretation) and proof contexts (interpret).  These take an
   159   instantiation of the locale parameters and compute proof obligations from
   160   the instantiated specification.  After the obligations have been discharged,
   161   the instantiated theorems of the locale are added to the theory or proof
   162   context.  Interpretation is smart in that already active interpretations
   163   do not occur in proof obligations, neither are instantiated theorems stored
   164   in duplicate.
   165   Use print_interps to inspect active interpretations of a particular locale.
   166   For details, see the Isar Reference manual.
   167 
   168 * Locales: proper static binding of attribute syntax -- i.e. types /
   169   terms / facts mentioned as arguments are always those of the locale
   170   definition context, independently of the context of later
   171   invocations.  Moreover, locale operations (renaming and type / term
   172   instantiation) are applied to attribute arguments as expected.
   173 
   174   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   175   of actual attributes; rare situations may require Attrib.attribute
   176   to embed those attributes into Attrib.src that lack concrete syntax.
   177 
   178   Attribute implementations need to cooperate properly with the static
   179   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   180   Attrib.XXX_thm etc. already do the right thing without further
   181   intervention.  Only unusual applications -- such as "where" or "of"
   182   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   183   both on the context and the facts involved -- may have to assign
   184   parsed values to argument tokens explicitly.
   185 
   186 * Attributes 'induct' and 'cases': type or set names may now be
   187   locally fixed variables as well.
   188 
   189 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   190   selections of theorems in named facts via indices.
   191 
   192 
   193 *** Document preparation ***
   194 
   195 * New antiquotations @{lhs thm} and @{rhs thm} printing the lhs/rhs of
   196   definitions, equations, inequations etc.
   197 
   198 * Antiquotations now provide the option 'locale=NAME' to specify an
   199   alternative context used for evaluating and printing the subsequent
   200   argument, as in @{thm [locale=LC] fold_commute}, for example.
   201 
   202 * Commands 'display_drafts' and 'print_drafts' perform simple output
   203   of raw sources.  Only those symbols that do not require additional
   204   LaTeX packages (depending on comments in isabellesym.sty) are
   205   displayed properly, everything else is left verbatim.  We use
   206   isatool display and isatool print as front ends; these are subject
   207   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   208 
   209 * Proof scripts as well as some other commands such as ML or
   210   parse/print_translation can now be hidden in the document.  Hiding
   211   is enabled by default, and can be disabled either via the option '-H
   212   false' of isatool usedir or by resetting the reference variable
   213   IsarOutput.hide_commands. Additional commands to be hidden may be
   214   declared using IsarOutput.add_hidden_commands.
   215 
   216 
   217 *** HOL ***
   218 
   219 * Datatype induction via method `induct' now preserves the name of the
   220   induction variable. For example, when proving P(xs::'a list) by induction
   221   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   222   P(list) ==> P(a#list) as previously.
   223 
   224 * HOL/record: reimplementation of records. Improved scalability for
   225   records with many fields, avoiding performance problems for type
   226   inference. Records are no longer composed of nested field types, but
   227   of nested extension types. Therefore the record type only grows
   228   linear in the number of extensions and not in the number of fields.
   229   The top-level (users) view on records is preserved.  Potential
   230   INCOMPATIBILITY only in strange cases, where the theory depends on
   231   the old record representation. The type generated for a record is
   232   called <record_name>_ext_type.
   233 
   234 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   235   enabled to skip the proofs triggered by a record definition or a
   236   simproc (if quick_and_dirty is enabled). Definitions of large
   237   records can take quite long.
   238 
   239 * HOL/record: "record_upd_simproc" for simplification of multiple
   240   record updates enabled by default.  Moreover, trivial updates are
   241   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   242   occasionally, since simplification is more powerful by default.
   243 
   244 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   245 
   246   syntax (epsilon)
   247     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   248 
   249   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   250   and x-symbol; use option '-m epsilon' to get it actually printed.
   251   Moreover, the mathematically important symbolic identifier
   252   \<epsilon> becomes available as variable, constant etc.
   253 
   254 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   255   Similarly for all quantifiers: "ALL x > y" etc.
   256   The x-symbol for >= is \<ge>.
   257 
   258 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}"
   259            (and similarly for "\<in>" instead of ":")
   260 
   261 * HOL/SetInterval: The syntax for open intervals has changed:
   262 
   263   Old         New
   264   {..n(}   -> {..<n}
   265   {)n..}   -> {n<..}
   266   {m..n(}  -> {m..<n}
   267   {)m..n}  -> {m<..n}
   268   {)m..n(} -> {m<..<n}
   269 
   270   The old syntax is still supported but will disappear in the future.
   271   For conversion use the following emacs search and replace patterns:
   272 
   273   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   274   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   275 
   276   They are not perfect but work quite well.
   277 
   278 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   279 
   280   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   281   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   282 
   283   There is new syntax for summation over finite sets:
   284 
   285   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   286   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   287   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   288   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   289 
   290   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   291   now translates into 'setsum' as above.
   292 
   293 * HOL: Finite set induction: In Isar proofs, the insert case is now
   294   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   295 
   296 * HOL/Simplifier:
   297 
   298   - Is now set up to reason about transitivity chains involving "trancl"
   299   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   300   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   301   occasionally as simplification may now solve more goals than previously.
   302 
   303   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   304   all partial orders (class "order"), in particular numbers and sets. For
   305   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   306 
   307   - Simproc for "let x = a in f x"
   308   If a is a free or bound variable or a constant then the let is unfolded.
   309   Otherwise first a is simplified to a', and then f a' is simplified to
   310   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   311   otherwise we unfold the let and arrive at g. The simproc can be 
   312   enabled/disabled by the reference use_let_simproc. Potential
   313   INCOMPATIBILITY since simplification is more powerful by default.
   314 
   315 * HOL: The 'refute' command has been extended to support a much larger
   316   fragment of HOL, including axiomatic type classes, constdefs and typedefs,
   317   inductive datatypes and recursion.
   318 
   319 
   320 *** HOLCF ***
   321 
   322 * HOLCF: discontinued special version of 'constdefs' (which used to
   323   support continuous functions) in favor of the general Pure one with
   324   full type-inference.
   325 
   326 
   327 *** ZF ***
   328 
   329 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   330   First Isomorphism Theorem (on quotienting by the kernel of a
   331   homomorphism).
   332 
   333 * ZF/Simplifier: install second copy of type solver that actually
   334   makes use of TC rules declared to Isar proof contexts (or locales);
   335   the old version is still required for ML proof scripts.
   336 
   337 
   338 *** System ***
   339 
   340 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   341   (containing Boolean satisfiability problems) into Isabelle/HOL
   342   theories.
   343 
   344 * isatool usedir: option -f allows specification of the ML file to be
   345   used by Isabelle; default is ROOT.ML.
   346 
   347 * symlinks to Isabelle, isabelle, isabelle-interface and isabelle-process
   348   are allowed; isabelle directories are determined based on link target.
   349 
   350 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   351   isatool doc, isatool mkdir, display_drafts etc.).
   352 
   353 
   354 *** ML ***
   355 
   356 * Pure: output via the Isabelle channels of writeln/warning/error
   357   etc. is now passed through Output.output, with a hook for arbitrary
   358   transformations depending on the print_mode (cf. Output.add_mode --
   359   the first active mode that provides a output function wins).
   360   Already formatted output may be embedded into further text via
   361   Output.raw; the result of Pretty.string_of/str_of and derived
   362   functions (string_of_term/cterm/thm etc.) is already marked raw to
   363   accommodate easy composition of diagnostic messages etc.
   364   Programmers rarely need to care about Output.output or Output.raw at
   365   all, with some notable exceptions: Output.output is required when
   366   bypassing the standard channels (writeln etc.), or in token
   367   translations to produce properly formatted results; Output.raw is
   368   required when capturing already output material that will eventually
   369   be presented to the user a second time.  For the default print mode,
   370   both Output.output and Output.raw have no effect.
   371 
   372 * Provers: Simplifier and Classical Reasoner now support proof context
   373   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   374   components are stored in the theory and patched into the
   375   simpset/claset when used in an Isar proof context.  Context
   376   dependent components are maintained by the following theory
   377   operations:
   378 
   379     Simplifier.add_context_simprocs
   380     Simplifier.del_context_simprocs
   381     Simplifier.set_context_subgoaler
   382     Simplifier.reset_context_subgoaler
   383     Simplifier.add_context_looper
   384     Simplifier.del_context_looper
   385     Simplifier.add_context_unsafe_solver
   386     Simplifier.add_context_safe_solver
   387 
   388     Classical.add_context_safe_wrapper
   389     Classical.del_context_safe_wrapper
   390     Classical.add_context_unsafe_wrapper
   391     Classical.del_context_unsafe_wrapper
   392 
   393   IMPORTANT NOTE: proof tools (methods etc.) need to use
   394   local_simpset_of and local_claset_of to instead of the primitive
   395   Simplifier.get_local_simpset and Classical.get_local_claset,
   396   respectively, in order to see the context dependent fields!
   397 
   398 
   399 
   400 New in Isabelle2004 (April 2004)
   401 --------------------------------
   402 
   403 *** General ***
   404 
   405 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   406   Replaces linorder.ML.
   407 
   408 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   409   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   410   (\<a>...\<z>), are now considered normal letters, and can therefore
   411   be used anywhere where an ASCII letter (a...zA...Z) has until
   412   now. COMPATIBILITY: This obviously changes the parsing of some
   413   terms, especially where a symbol has been used as a binder, say
   414   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   415   as an identifier.  Fix it by inserting a space around former
   416   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   417   existing theory and ML files.
   418 
   419 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   420 
   421 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   422   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   423   a normal (but invisible) letter. For multiple letter subscripts repeat
   424   \<^isub> like this: x\<^isub>1\<^isub>2.
   425 
   426 * Pure: There are now sub-/superscripts that can span more than one
   427   character. Text between \<^bsub> and \<^esub> is set in subscript in
   428   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   429   superscript. The new control characters are not identifier parts.
   430 
   431 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   432   content of "..." to the latex file instead of \isacntrl... . The "..."
   433   may consist of any printable characters excluding the end bracket >.
   434 
   435 * Pure: Using new Isar command "finalconsts" (or the ML functions
   436   Theory.add_finals or Theory.add_finals_i) it is now possible to
   437   declare constants "final", which prevents their being given a definition
   438   later.  It is useful for constants whose behaviour is fixed axiomatically
   439   rather than definitionally, such as the meta-logic connectives.
   440 
   441 * Pure: 'instance' now handles general arities with general sorts
   442   (i.e. intersections of classes),
   443 
   444 * Presentation: generated HTML now uses a CSS style sheet to make layout
   445   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   446   It can be changed to alter the colors/layout of generated pages.
   447 
   448 
   449 *** Isar ***
   450 
   451 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   452   cut_tac, subgoal_tac and thin_tac:
   453   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   454     locales are no longer forced to write Isar proof scripts.
   455     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   456     emulations.
   457   - INCOMPATIBILITY: names of variables to be instantiated may no
   458     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   459     This is consistent with the instantiation attribute "where".
   460 
   461 * Attributes "where" and "of":
   462   - Now take type variables of instantiated theorem into account when reading
   463     the instantiation string.  This fixes a bug that caused instantiated
   464     theorems to have too special types in some circumstances.
   465   - "where" permits explicit instantiations of type variables.
   466 
   467 * Calculation commands "moreover" and "also" no longer interfere with
   468   current facts ("this"), admitting arbitrary combinations with "then"
   469   and derived forms.
   470 
   471 * Locales:
   472   - Goal statements involving the context element "includes" no longer
   473     generate theorems with internal delta predicates (those ending on
   474     "_axioms") in the premise.
   475     Resolve particular premise with <locale>.intro to obtain old form.
   476   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   477     specification and "includes" elements in goal statement.
   478   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   479     [intro?] and [elim?] (respectively) by default.
   480   - Experimental command for instantiation of locales in proof contexts:
   481         instantiate <label>[<attrs>]: <loc>
   482     Instantiates locale <loc> and adds all its theorems to the current context
   483     taking into account their attributes.  Label and attrs are optional
   484     modifiers, like in theorem declarations.  If present, names of
   485     instantiated theorems are qualified with <label>, and the attributes
   486     <attrs> are applied after any attributes these theorems might have already.
   487       If the locale has assumptions, a chained fact of the form
   488     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   489     are derived.  The command does not support old-style locales declared
   490     with "locale (open)".
   491       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   492 
   493 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   494   (Isar) contexts.
   495 
   496 
   497 *** HOL ***
   498 
   499 * Proof import: new image HOL4 contains the imported library from
   500   the HOL4 system with about 2500 theorems. It is imported by
   501   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   502   can be used like any other Isabelle image.  See
   503   HOL/Import/HOL/README for more information.
   504 
   505 * Simplifier:
   506   - Much improved handling of linear and partial orders.
   507     Reasoners for linear and partial orders are set up for type classes
   508     "linorder" and "order" respectively, and are added to the default simpset
   509     as solvers.  This means that the simplifier can build transitivity chains
   510     to solve goals from the assumptions.
   511   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   512     of blast or auto after simplification become unnecessary because the goal
   513     is solved by simplification already.
   514 
   515 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   516     all proved in axiomatic type classes for semirings, rings and fields.
   517 
   518 * Numerics:
   519   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   520     now formalized using the Ring_and_Field theory mentioned above.
   521   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   522     than before, because now they are set up once in a generic manner.
   523   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   524     Look for the general versions in Ring_and_Field (and Power if they concern
   525     exponentiation).
   526 
   527 * Type "rat" of the rational numbers is now available in HOL-Complex.
   528 
   529 * Records:
   530   - Record types are now by default printed with their type abbreviation
   531     instead of the list of all field types. This can be configured via
   532     the reference "print_record_type_abbr".
   533   - Simproc "record_upd_simproc" for simplification of multiple updates added
   534     (not enabled by default).
   535   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   536     EX x. x = sel r to True (not enabled by default).
   537   - Tactic "record_split_simp_tac" to split and simplify records added.
   538 
   539 * 'specification' command added, allowing for definition by
   540   specification.  There is also an 'ax_specification' command that
   541   introduces the new constants axiomatically.
   542 
   543 * arith(_tac) is now able to generate counterexamples for reals as well.
   544 
   545 * HOL-Algebra: new locale "ring" for non-commutative rings.
   546 
   547 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   548   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   549 
   550 * HOL-Matrix: a first theory for matrices in HOL with an application of
   551   matrix theory to linear programming.
   552 
   553 * Unions and Intersections:
   554   The latex output syntax of UN and INT has been changed
   555   from "\Union x \in A. B" to "\Union_{x \in A} B"
   556   i.e. the index formulae has become a subscript.
   557   Similarly for "\Union x. B", and for \Inter instead of \Union.
   558 
   559 * Unions and Intersections over Intervals:
   560   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   561   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   562   like in normal math, and corresponding versions for < and for intersection.
   563 
   564 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   565   lexicographic dictonary ordering has been added as "lexord".
   566 
   567 * ML: the legacy theory structures Int and List have been removed. They had
   568   conflicted with ML Basis Library structures having the same names.
   569 
   570 * 'refute' command added to search for (finite) countermodels.  Only works
   571   for a fragment of HOL.  The installation of an external SAT solver is
   572   highly recommended.  See "HOL/Refute.thy" for details.
   573 
   574 * 'quickcheck' command: Allows to find counterexamples by evaluating
   575   formulae under an assignment of free variables to random values.
   576   In contrast to 'refute', it can deal with inductive datatypes,
   577   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   578   for examples.
   579 
   580 
   581 *** HOLCF ***
   582 
   583 * Streams now come with concatenation and are part of the HOLCF image
   584 
   585 
   586 
   587 New in Isabelle2003 (May 2003)
   588 ------------------------------
   589 
   590 *** General ***
   591 
   592 * Provers/simplifier:
   593 
   594   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   595     Assumptions are now subject to complete mutual simplification,
   596     not just from left to right. The simplifier now preserves
   597     the order of assumptions.
   598 
   599     Potential INCOMPATIBILITY:
   600 
   601     -- simp sometimes diverges where the old version did
   602        not, e.g. invoking simp on the goal
   603 
   604         [| P (f x); y = x; f x = f y |] ==> Q
   605 
   606        now gives rise to the infinite reduction sequence
   607 
   608         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   609 
   610        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   611        kind of problem.
   612 
   613     -- Tactics combining classical reasoner and simplification (such as auto)
   614        are also affected by this change, because many of them rely on
   615        simp. They may sometimes diverge as well or yield a different numbers
   616        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   617        in case of problems. Sometimes subsequent calls to the classical
   618        reasoner will fail because a preceeding call to the simplifier too
   619        eagerly simplified the goal, e.g. deleted redundant premises.
   620 
   621   - The simplifier trace now shows the names of the applied rewrite rules
   622 
   623   - You can limit the number of recursive invocations of the simplifier
   624     during conditional rewriting (where the simplifie tries to solve the
   625     conditions before applying the rewrite rule):
   626     ML "simp_depth_limit := n"
   627     where n is an integer. Thus you can force termination where previously
   628     the simplifier would diverge.
   629 
   630   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   631 
   632   - No longer aborts on failed congruence proof.  Instead, the
   633     congruence is ignored.
   634 
   635 * Pure: New generic framework for extracting programs from constructive
   636   proofs. See HOL/Extraction.thy for an example instantiation, as well
   637   as HOL/Extraction for some case studies.
   638 
   639 * Pure: The main goal of the proof state is no longer shown by default, only
   640 the subgoals. This behaviour is controlled by a new flag.
   641    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   642 (ML: Proof.show_main_goal).
   643 
   644 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   645 rules whose conclusion matches subgoal 1:
   646       PG menu: Isabelle/Isar -> Show me -> matching rules
   647 The rules are ordered by how closely they match the subgoal.
   648 In particular, rules that solve a subgoal outright are displayed first
   649 (or rather last, the way they are printed).
   650 (ML: ProofGeneral.print_intros())
   651 
   652 * Pure: New flag trace_unify_fail causes unification to print
   653 diagnostic information (PG: in trace buffer) when it fails. This is
   654 useful for figuring out why single step proofs like rule, erule or
   655 assumption failed.
   656 
   657 * Pure: Locale specifications now produce predicate definitions
   658 according to the body of text (covering assumptions modulo local
   659 definitions); predicate "loc_axioms" covers newly introduced text,
   660 while "loc" is cumulative wrt. all included locale expressions; the
   661 latter view is presented only on export into the global theory
   662 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   663 on the old view without predicates;
   664 
   665 * Pure: predefined locales "var" and "struct" are useful for sharing
   666 parameters (as in CASL, for example); just specify something like
   667 ``var x + var y + struct M'' as import;
   668 
   669 * Pure: improved thms_containing: proper indexing of facts instead of
   670 raw theorems; check validity of results wrt. current name space;
   671 include local facts of proof configuration (also covers active
   672 locales), cover fixed variables in index; may use "_" in term
   673 specification; an optional limit for the number of printed facts may
   674 be given (the default is 40);
   675 
   676 * Pure: disallow duplicate fact bindings within new-style theory files
   677 (batch-mode only);
   678 
   679 * Provers: improved induct method: assumptions introduced by case
   680 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   681 the goal statement); "foo" still refers to all facts collectively;
   682 
   683 * Provers: the function blast.overloaded has been removed: all constants
   684 are regarded as potentially overloaded, which improves robustness in exchange
   685 for slight decrease in efficiency;
   686 
   687 * Provers/linorder: New generic prover for transitivity reasoning over
   688 linear orders.  Note: this prover is not efficient!
   689 
   690 * Isar: preview of problems to finish 'show' now produce an error
   691 rather than just a warning (in interactive mode);
   692 
   693 
   694 *** HOL ***
   695 
   696 * arith(_tac)
   697 
   698  - Produces a counter example if it cannot prove a goal.
   699    Note that the counter example may be spurious if the goal is not a formula
   700    of quantifier-free linear arithmetic.
   701    In ProofGeneral the counter example appears in the trace buffer.
   702 
   703  - Knows about div k and mod k where k is a numeral of type nat or int.
   704 
   705  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   706    linear arithmetic fails. This takes account of quantifiers and divisibility.
   707    Presburger arithmetic can also be called explicitly via presburger(_tac).
   708 
   709 * simp's arithmetic capabilities have been enhanced a bit: it now
   710 takes ~= in premises into account (by performing a case split);
   711 
   712 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   713 are distributed over a sum of terms;
   714 
   715 * New tactic "trans_tac" and method "trans" instantiate
   716 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   717 "<=", "<" and "=").
   718 
   719 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   720 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   721 
   722 * 'typedef' command has new option "open" to suppress the set
   723 definition;
   724 
   725 * functions Min and Max on finite sets have been introduced (theory
   726 Finite_Set);
   727 
   728 * attribute [symmetric] now works for relations as well; it turns
   729 (x,y) : R^-1 into (y,x) : R, and vice versa;
   730 
   731 * induct over a !!-quantified statement (say !!x1..xn):
   732   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   733 
   734 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   735 %x. None. Warning: empty_def now refers to the previously hidden definition
   736 of the empty set.
   737 
   738 * Algebra: formalization of classical algebra.  Intended as base for
   739 any algebraic development in Isabelle.  Currently covers group theory
   740 (up to Sylow's theorem) and ring theory (Universal Property of
   741 Univariate Polynomials).  Contributions welcome;
   742 
   743 * GroupTheory: deleted, since its material has been moved to Algebra;
   744 
   745 * Complex: new directory of the complex numbers with numeric constants,
   746 nonstandard complex numbers, and some complex analysis, standard and
   747 nonstandard (Jacques Fleuriot);
   748 
   749 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   750 
   751 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   752 Fleuriot);
   753 
   754 * Real/HahnBanach: updated and adapted to locales;
   755 
   756 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   757 Gray and Kramer);
   758 
   759 * UNITY: added the Meier-Sanders theory of progress sets;
   760 
   761 * MicroJava: bytecode verifier and lightweight bytecode verifier
   762 as abstract algorithms, instantiated to the JVM;
   763 
   764 * Bali: Java source language formalization. Type system, operational
   765 semantics, axiomatic semantics. Supported language features:
   766 classes, interfaces, objects,virtual methods, static methods,
   767 static/instance fields, arrays, access modifiers, definite
   768 assignment, exceptions.
   769 
   770 
   771 *** ZF ***
   772 
   773 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   774 universe, etc.);
   775 
   776 * Main ZF: virtually all theories converted to new-style format;
   777 
   778 
   779 *** ML ***
   780 
   781 * Pure: Tactic.prove provides sane interface for internal proofs;
   782 omits the infamous "standard" operation, so this is more appropriate
   783 than prove_goalw_cterm in many situations (e.g. in simprocs);
   784 
   785 * Pure: improved error reporting of simprocs;
   786 
   787 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   788 up simprocs;
   789 
   790 
   791 *** Document preparation ***
   792 
   793 * uses \par instead of \\ for line breaks in theory text. This may
   794 shift some page breaks in large documents. To get the old behaviour
   795 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   796 
   797 * minimized dependencies of isabelle.sty and isabellesym.sty on
   798 other packages
   799 
   800 * \<euro> now needs package babel/greek instead of marvosym (which
   801 broke \Rightarrow)
   802 
   803 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   804 textcomp package)
   805 
   806 
   807 
   808 New in Isabelle2002 (March 2002)
   809 --------------------------------
   810 
   811 *** Document preparation ***
   812 
   813 * greatly simplified document preparation setup, including more
   814 graceful interpretation of isatool usedir -i/-d/-D options, and more
   815 instructive isatool mkdir; users should basically be able to get
   816 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   817 users may run a separate document processing stage manually like this:
   818 "isatool usedir -D output HOL Test && isatool document Test/output";
   819 
   820 * theory dependency graph may now be incorporated into documents;
   821 isatool usedir -g true will produce session_graph.eps/.pdf for use
   822 with \includegraphics of LaTeX;
   823 
   824 * proper spacing of consecutive markup elements, especially text
   825 blocks after section headings;
   826 
   827 * support bold style (for single symbols only), input syntax is like
   828 this: "\<^bold>\<alpha>" or "\<^bold>A";
   829 
   830 * \<bullet> is now output as bold \cdot by default, which looks much
   831 better in printed text;
   832 
   833 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   834 note that these symbols are currently unavailable in Proof General /
   835 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   836 
   837 * isatool latex no longer depends on changed TEXINPUTS, instead
   838 isatool document copies the Isabelle style files to the target
   839 location;
   840 
   841 
   842 *** Isar ***
   843 
   844 * Pure/Provers: improved proof by cases and induction;
   845   - 'case' command admits impromptu naming of parameters (such as
   846     "case (Suc n)");
   847   - 'induct' method divinates rule instantiation from the inductive
   848     claim; no longer requires excessive ?P bindings for proper
   849     instantiation of cases;
   850   - 'induct' method properly enumerates all possibilities of set/type
   851     rules; as a consequence facts may be also passed through *type*
   852     rules without further ado;
   853   - 'induct' method now derives symbolic cases from the *rulified*
   854     rule (before it used to rulify cases stemming from the internal
   855     atomized version); this means that the context of a non-atomic
   856     statement becomes is included in the hypothesis, avoiding the
   857     slightly cumbersome show "PROP ?case" form;
   858   - 'induct' may now use elim-style induction rules without chaining
   859     facts, using ``missing'' premises from the goal state; this allows
   860     rules stemming from inductive sets to be applied in unstructured
   861     scripts, while still benefitting from proper handling of non-atomic
   862     statements; NB: major inductive premises need to be put first, all
   863     the rest of the goal is passed through the induction;
   864   - 'induct' proper support for mutual induction involving non-atomic
   865     rule statements (uses the new concept of simultaneous goals, see
   866     below);
   867   - append all possible rule selections, but only use the first
   868     success (no backtracking);
   869   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   870   - undeclared rule case names default to numbers 1, 2, 3, ...;
   871   - added 'print_induct_rules' (covered by help item in recent Proof
   872     General versions);
   873   - moved induct/cases attributes to Pure, methods to Provers;
   874   - generic method setup instantiated for FOL and HOL;
   875 
   876 * Pure: support multiple simultaneous goal statements, for example
   877 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   878 meta-level mechanism, this acts as if several individual goals had
   879 been stated separately; in particular common proof methods need to be
   880 repeated in order to cover all claims; note that a single elimination
   881 step is *not* sufficient to establish the two conjunctions, so this
   882 fails:
   883 
   884   assume "A & B" then have A and B ..   (*".." fails*)
   885 
   886 better use "obtain" in situations as above; alternative refer to
   887 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   888 
   889 * Pure: proper integration with ``locales''; unlike the original
   890 version by Florian Kammller, Isar locales package high-level proof
   891 contexts rather than raw logical ones (e.g. we admit to include
   892 attributes everywhere); operations on locales include merge and
   893 rename; support for implicit arguments (``structures''); simultaneous
   894 type-inference over imports and text; see also HOL/ex/Locales.thy for
   895 some examples;
   896 
   897 * Pure: the following commands have been ``localized'', supporting a
   898 target locale specification "(in name)": 'lemma', 'theorem',
   899 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   900 stored both within the locale and at the theory level (exported and
   901 qualified by the locale name);
   902 
   903 * Pure: theory goals may now be specified in ``long'' form, with
   904 ad-hoc contexts consisting of arbitrary locale elements. for example
   905 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   906 definitions may be given, too); the result is a meta-level rule with
   907 the context elements being discharged in the obvious way;
   908 
   909 * Pure: new proof command 'using' allows to augment currently used
   910 facts after a goal statement ('using' is syntactically analogous to
   911 'apply', but acts on the goal's facts only); this allows chained facts
   912 to be separated into parts given before and after a claim, as in
   913 ``from a and b have C using d and e <proof>'';
   914 
   915 * Pure: renamed "antecedent" case to "rule_context";
   916 
   917 * Pure: new 'judgment' command records explicit information about the
   918 object-logic embedding (used by several tools internally); no longer
   919 use hard-wired "Trueprop";
   920 
   921 * Pure: added 'corollary' command;
   922 
   923 * Pure: fixed 'token_translation' command;
   924 
   925 * Pure: removed obsolete 'exported' attribute;
   926 
   927 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   928 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   929 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   930 
   931 * Pure: method 'atomize' presents local goal premises as object-level
   932 statements (atomic meta-level propositions); setup controlled via
   933 rewrite rules declarations of 'atomize' attribute; example
   934 application: 'induct' method with proper rule statements in improper
   935 proof *scripts*;
   936 
   937 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   938 now consider the syntactic context of assumptions, giving a better
   939 chance to get type-inference of the arguments right (this is
   940 especially important for locales);
   941 
   942 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   943 mode;
   944 
   945 * Pure/obtain: the formal conclusion "thesis", being marked as
   946 ``internal'', may no longer be reference directly in the text;
   947 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   948 situations;
   949 
   950 * Pure: generic 'sym' attribute which declares a rule both as pure
   951 'elim?' and for the 'symmetric' operation;
   952 
   953 * Pure: marginal comments ``--'' may now occur just anywhere in the
   954 text; the fixed correlation with particular command syntax has been
   955 discontinued;
   956 
   957 * Pure: new method 'rules' is particularly well-suited for proof
   958 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   959 but often produces more compact proof terms with less detours;
   960 
   961 * Pure/Provers/classical: simplified integration with pure rule
   962 attributes and methods; the classical "intro?/elim?/dest?"
   963 declarations coincide with the pure ones; the "rule" method no longer
   964 includes classically swapped intros; "intro" and "elim" methods no
   965 longer pick rules from the context; also got rid of ML declarations
   966 AddXIs/AddXEs/AddXDs; all of this has some potential for
   967 INCOMPATIBILITY;
   968 
   969 * Provers/classical: attribute 'swapped' produces classical inversions
   970 of introduction rules;
   971 
   972 * Provers/simplifier: 'simplified' attribute may refer to explicit
   973 rules instead of full simplifier context; 'iff' attribute handles
   974 conditional rules;
   975 
   976 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   977 
   978 * HOL: 'recdef' now fails on unfinished automated proofs, use
   979 "(permissive)" option to recover old behavior;
   980 
   981 * HOL: 'inductive' no longer features separate (collective) attributes
   982 for 'intros' (was found too confusing);
   983 
   984 * HOL: properly declared induction rules less_induct and
   985 wf_induct_rule;
   986 
   987 
   988 *** HOL ***
   989 
   990 * HOL: moved over to sane numeral syntax; the new policy is as
   991 follows:
   992 
   993   - 0 and 1 are polymorphic constants, which are defined on any
   994   numeric type (nat, int, real etc.);
   995 
   996   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
   997   binary representation internally;
   998 
   999   - type nat has special constructor Suc, and generally prefers Suc 0
  1000   over 1::nat and Suc (Suc 0) over 2::nat;
  1001 
  1002 This change may cause significant problems of INCOMPATIBILITY; here
  1003 are some hints on converting existing sources:
  1004 
  1005   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1006   entities, so expressions involving "-" (unary or binary minus) need
  1007   to be spaced properly;
  1008 
  1009   - existing occurrences of "1" may need to be constraint "1::nat" or
  1010   even replaced by Suc 0; similar for old "2";
  1011 
  1012   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1013 
  1014   - remove all special provisions on numerals in proofs;
  1015 
  1016 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1017 representation (depends on bin_arith_simps in the default context);
  1018 
  1019 * HOL: symbolic syntax for x^2 (numeral 2);
  1020 
  1021 * HOL: the class of all HOL types is now called "type" rather than
  1022 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1023 in axclass/classes, instance/arities, and (usually rare) occurrences
  1024 in typings (of consts etc.); internally the class is called
  1025 "HOL.type", ML programs should refer to HOLogic.typeS;
  1026 
  1027 * HOL/record package improvements:
  1028   - new derived operations "fields" to build a partial record section,
  1029     "extend" to promote a fixed record to a record scheme, and
  1030     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1031     declared as simp by default;
  1032   - shared operations ("more", "fields", etc.) now need to be always
  1033     qualified) --- potential INCOMPATIBILITY;
  1034   - removed "make_scheme" operations (use "make" with "extend") --
  1035     INCOMPATIBILITY;
  1036   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1037   - provides cases/induct rules for use with corresponding Isar
  1038     methods (for concrete records, record schemes, concrete more
  1039     parts, and schematic more parts -- in that order);
  1040   - internal definitions directly based on a light-weight abstract
  1041     theory of product types over typedef rather than datatype;
  1042 
  1043 * HOL: generic code generator for generating executable ML code from
  1044 specifications; specific support for HOL constructs such as inductive
  1045 datatypes and sets, as well as recursive functions; can be invoked
  1046 via 'generate_code' theory section;
  1047 
  1048 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1049 
  1050 * HOL: consolidated and renamed several theories.  In particular:
  1051         Ord.thy has been absorbed into HOL.thy
  1052         String.thy has been absorbed into List.thy
  1053 
  1054 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1055 (beware of argument permutation!);
  1056 
  1057 * HOL: linorder_less_split superseded by linorder_cases;
  1058 
  1059 * HOL/List: "nodups" renamed to "distinct";
  1060 
  1061 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1062 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1063   - Ex_def has changed, now need to use some_eq_ex
  1064 
  1065 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1066 in this (rare) case use:
  1067 
  1068   delSWrapper "split_all_tac"
  1069   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1070 
  1071 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1072 MAY FAIL;
  1073 
  1074 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1075 Isabelle's type classes, ^ on functions and relations has too general
  1076 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1077 necessary to attach explicit type constraints;
  1078 
  1079 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1080 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1081 renamed accordingly (eg "compI" -> "rel_compI").
  1082 
  1083 * HOL: syntax translations now work properly with numerals and records
  1084 expressions;
  1085 
  1086 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1087 of "lam" -- INCOMPATIBILITY;
  1088 
  1089 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1090 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1091 renamed "Product_Type.unit";
  1092 
  1093 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1094 
  1095 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1096 the "cases" method);
  1097 
  1098 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1099 Florian Kammller);
  1100 
  1101 * HOL/IMP: updated and converted to new-style theory format; several
  1102 parts turned into readable document, with proper Isar proof texts and
  1103 some explanations (by Gerwin Klein);
  1104 
  1105 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1106 
  1107 * HOL-Hyperreal is now a logic image;
  1108 
  1109 
  1110 *** HOLCF ***
  1111 
  1112 * Isar: consts/constdefs supports mixfix syntax for continuous
  1113 operations;
  1114 
  1115 * Isar: domain package adapted to new-style theory format, e.g. see
  1116 HOLCF/ex/Dnat.thy;
  1117 
  1118 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1119 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1120 lift.induct_tac, always use UU instead of Undef;
  1121 
  1122 * HOLCF/IMP: updated and converted to new-style theory;
  1123 
  1124 
  1125 *** ZF ***
  1126 
  1127 * Isar: proper integration of logic-specific tools and packages,
  1128 including theory commands '(co)inductive', '(co)datatype',
  1129 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1130 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1131 
  1132 * theory Main no longer includes AC; for the Axiom of Choice, base
  1133 your theory on Main_ZFC;
  1134 
  1135 * the integer library now covers quotients and remainders, with many
  1136 laws relating division to addition, multiplication, etc.;
  1137 
  1138 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1139 typeless version of the formalism;
  1140 
  1141 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1142 format;
  1143 
  1144 * ZF/Induct: new directory for examples of inductive definitions,
  1145 including theory Multiset for multiset orderings; converted to
  1146 new-style theory format;
  1147 
  1148 * ZF: many new theorems about lists, ordinals, etc.;
  1149 
  1150 
  1151 *** General ***
  1152 
  1153 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1154 variable proof controls level of detail: 0 = no proofs (only oracle
  1155 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1156 also ref manual for further ML interfaces;
  1157 
  1158 * Pure/axclass: removed obsolete ML interface
  1159 goal_subclass/goal_arity;
  1160 
  1161 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1162 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1163 separate tokens, so expressions involving minus need to be spaced
  1164 properly;
  1165 
  1166 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1167 rather than "infixl" or "infixr";
  1168 
  1169 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1170 sort constraint specifications in type inference; e.g. "x::_::foo"
  1171 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1172 type variable);
  1173 
  1174 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1175 control output of nested => (types); the default behavior is
  1176 "type_brackets";
  1177 
  1178 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1179 tokens into AST constants;
  1180 
  1181 * Pure/syntax: prefer later declarations of translations and print
  1182 translation functions; potential INCOMPATIBILITY: need to reverse
  1183 multiple declarations for same syntax element constant;
  1184 
  1185 * Pure/show_hyps reset by default (in accordance to existing Isar
  1186 practice);
  1187 
  1188 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1189 addSafter;
  1190 
  1191 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1192 as well;
  1193 
  1194 * system: tested support for MacOS X; should be able to get Isabelle +
  1195 Proof General to work in a plain Terminal after installing Poly/ML
  1196 (e.g. from the Isabelle distribution area) and GNU bash alone
  1197 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1198 support requires further installations, e.g. from
  1199 http://fink.sourceforge.net/);
  1200 
  1201 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1202 
  1203 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1204 of 40 MB), cf. ML_OPTIONS;
  1205 
  1206 * system: Proof General keywords specification is now part of the
  1207 Isabelle distribution (see etc/isar-keywords.el);
  1208 
  1209 * system: support for persistent Proof General sessions (refrain from
  1210 outdating all loaded theories on startup); user may create writable
  1211 logic images like this: ``isabelle -q HOL Test'';
  1212 
  1213 * system: smart selection of Isabelle process versus Isabelle
  1214 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1215 run both "isabelle" and "Isabelle" even if file names are badly
  1216 damaged (executable inspects the case of the first letter of its own
  1217 name); added separate "isabelle-process" and "isabelle-interface";
  1218 
  1219 * system: refrain from any attempt at filtering input streams; no
  1220 longer support ``8bit'' encoding of old isabelle font, instead proper
  1221 iso-latin characters may now be used; the related isatools
  1222 "symbolinput" and "nonascii" have disappeared as well;
  1223 
  1224 * system: removed old "xterm" interface (the print modes "xterm" and
  1225 "xterm_color" are still available for direct use in a suitable
  1226 terminal);
  1227 
  1228 
  1229 
  1230 New in Isabelle99-2 (February 2001)
  1231 -----------------------------------
  1232 
  1233 *** Overview of INCOMPATIBILITIES ***
  1234 
  1235 * HOL: please note that theories in the Library and elsewhere often use the
  1236 new-style (Isar) format; to refer to their theorems in an ML script you must
  1237 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1238 
  1239 * HOL: inductive package no longer splits induction rule aggressively,
  1240 but only as far as specified by the introductions given; the old
  1241 format may be recovered via ML function complete_split_rule or attribute
  1242 'split_rule (complete)';
  1243 
  1244 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1245 gfp_Tarski to gfp_unfold;
  1246 
  1247 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1248 
  1249 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1250 relation); infix "^^" has been renamed "``"; infix "``" has been
  1251 renamed "`"; "univalent" has been renamed "single_valued";
  1252 
  1253 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1254 operation;
  1255 
  1256 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1257 
  1258 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1259 
  1260 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1261 consequence, it is no longer monotonic wrt. the local goal context
  1262 (which is now passed through the inductive cases);
  1263 
  1264 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1265 \<gg> to \<ggreater>;
  1266 
  1267 
  1268 *** Document preparation ***
  1269 
  1270 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1271 available: are "it" for near math-mode best-style output, "sl" for
  1272 slanted text style, and "tt" for plain type-writer; if no
  1273 \isabellestyle command is given, output is according to slanted
  1274 type-writer);
  1275 
  1276 * support sub/super scripts (for single symbols only), input syntax is
  1277 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1278 
  1279 * some more standard symbols; see Appendix A of the system manual for
  1280 the complete list of symbols defined in isabellesym.sty;
  1281 
  1282 * improved isabelle style files; more abstract symbol implementation
  1283 (should now use \isamath{...} and \isatext{...} in custom symbol
  1284 definitions);
  1285 
  1286 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1287 state; Note that presentation of goal states does not conform to
  1288 actual human-readable proof documents.  Please do not include goal
  1289 states into document output unless you really know what you are doing!
  1290 
  1291 * proper indentation of antiquoted output with proportional LaTeX
  1292 fonts;
  1293 
  1294 * no_document ML operator temporarily disables LaTeX document
  1295 generation;
  1296 
  1297 * isatool unsymbolize tunes sources for plain ASCII communication;
  1298 
  1299 
  1300 *** Isar ***
  1301 
  1302 * Pure: Isar now suffers initial goal statements to contain unbound
  1303 schematic variables (this does not conform to actual readable proof
  1304 documents, due to unpredictable outcome and non-compositional proof
  1305 checking); users who know what they are doing may use schematic goals
  1306 for Prolog-style synthesis of proven results;
  1307 
  1308 * Pure: assumption method (an implicit finishing) now handles actual
  1309 rules as well;
  1310 
  1311 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1312 initial goal, declare "that" only as Pure intro (only for single
  1313 steps); the "that" rule assumption may now be involved in implicit
  1314 finishing, thus ".." becomes a feasible for trivial obtains;
  1315 
  1316 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1317 instance proofs may be performed by "..";
  1318 
  1319 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1320 statements as well;
  1321 
  1322 * Pure: more robust selection of calculational rules;
  1323 
  1324 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1325 rule (as well as the assumption rule);
  1326 
  1327 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1328 lemmas, using the graph browser tool;
  1329 
  1330 * Pure: predict failure of "show" in interactive mode;
  1331 
  1332 * Pure: 'thms_containing' now takes actual terms as arguments;
  1333 
  1334 * HOL: improved method 'induct' --- now handles non-atomic goals
  1335 (potential INCOMPATIBILITY); tuned error handling;
  1336 
  1337 * HOL: cases and induct rules now provide explicit hints about the
  1338 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1339 any remaining facts are inserted into the goal verbatim;
  1340 
  1341 * HOL: local contexts (aka cases) may now contain term bindings as
  1342 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1343 the result to be shown in each case;
  1344 
  1345 * HOL: added 'recdef_tc' command;
  1346 
  1347 * isatool convert assists in eliminating legacy ML scripts;
  1348 
  1349 
  1350 *** HOL ***
  1351 
  1352 * HOL/Library: a collection of generic theories to be used together
  1353 with main HOL; the theory loader path already includes this directory
  1354 by default; the following existing theories have been moved here:
  1355 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1356 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1357 
  1358 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1359 modelling and verification task performed in Isabelle/HOL +
  1360 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1361 
  1362 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1363 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1364 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1365 'domain', this makes the theory consistent with mathematical
  1366 literature;
  1367 
  1368 * HOL basics: added overloaded operations "inverse" and "divide"
  1369 (infix "/"), syntax for generic "abs" operation, generic summation
  1370 operator \<Sum>;
  1371 
  1372 * HOL/typedef: simplified package, provide more useful rules (see also
  1373 HOL/subset.thy);
  1374 
  1375 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1376 now expressed as a proper nested rule (old-style tactic scripts may
  1377 require atomize_strip_tac to cope with non-atomic premises);
  1378 
  1379 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1380 to "split_conv" (old name still available for compatibility);
  1381 
  1382 * HOL: improved concrete syntax for strings (e.g. allows translation
  1383 rules with string literals);
  1384 
  1385 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1386  and Fleuriot's mechanization of analysis, including the transcendental
  1387  functions for the reals;
  1388 
  1389 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1390 
  1391 
  1392 *** CTT ***
  1393 
  1394 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1395 "lam" is displayed as TWO lambda-symbols
  1396 
  1397 * CTT: theory Main now available, containing everything (that is, Bool
  1398 and Arith);
  1399 
  1400 
  1401 *** General ***
  1402 
  1403 * Pure: the Simplifier has been implemented properly as a derived rule
  1404 outside of the actual kernel (at last!); the overall performance
  1405 penalty in practical applications is about 50%, while reliability of
  1406 the Isabelle inference kernel has been greatly improved;
  1407 
  1408 * print modes "brackets" and "no_brackets" control output of nested =>
  1409 (types) and ==> (props); the default behaviour is "brackets";
  1410 
  1411 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1412 as assumptions as well;
  1413 
  1414 * system: support Poly/ML 4.0;
  1415 
  1416 * system: isatool install handles KDE version 1 or 2;
  1417 
  1418 
  1419 
  1420 New in Isabelle99-1 (October 2000)
  1421 ----------------------------------
  1422 
  1423 *** Overview of INCOMPATIBILITIES ***
  1424 
  1425 * HOL: simplification of natural numbers is much changed; to partly
  1426 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1427 issue the following ML commands:
  1428 
  1429   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1430   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1431 
  1432 * HOL: simplification no longer dives into case-expressions; this is
  1433 controlled by "t.weak_case_cong" for each datatype t;
  1434 
  1435 * HOL: nat_less_induct renamed to less_induct;
  1436 
  1437 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1438 fixsome to patch .thy and .ML sources automatically;
  1439 
  1440   select_equality  -> some_equality
  1441   select_eq_Ex     -> some_eq_ex
  1442   selectI2EX       -> someI2_ex
  1443   selectI2         -> someI2
  1444   selectI          -> someI
  1445   select1_equality -> some1_equality
  1446   Eps_sym_eq       -> some_sym_eq_trivial
  1447   Eps_eq           -> some_eq_trivial
  1448 
  1449 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1450 
  1451 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1452 instead);
  1453 
  1454 * HOL: the recursion equations generated by 'recdef' are now called
  1455 f.simps instead of f.rules;
  1456 
  1457 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1458 
  1459 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1460 sometimes be needed;
  1461 
  1462 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1463 
  1464 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1465 
  1466 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1467 product is now "<*>" instead of "Times"; the lexicographic product is
  1468 now "<*lex*>" instead of "**";
  1469 
  1470 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1471 of main HOL, but was unused); better use HOL's datatype package;
  1472 
  1473 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1474 the old syntax may be recovered as follows:
  1475 
  1476   syntax (symbols)
  1477     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1478       (infixl "\\<oplus>" 100)
  1479 
  1480 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1481 
  1482 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1483 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1484 internally;
  1485 
  1486 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1487 changed from A/r to A//r;
  1488 
  1489 * ZF: new treatment of arithmetic (nat & int) may break some old
  1490 proofs;
  1491 
  1492 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1493 rulify -> rule_format, elimify -> elim_format, ...);
  1494 
  1495 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1496 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1497 should have to change intro!! to intro? only); replaced "delrule" by
  1498 "rule del";
  1499 
  1500 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1501 
  1502 * Provers: strengthened force_tac by using new first_best_tac;
  1503 
  1504 * LaTeX document preparation: several changes of isabelle.sty (see
  1505 lib/texinputs);
  1506 
  1507 
  1508 *** Document preparation ***
  1509 
  1510 * formal comments (text blocks etc.) in new-style theories may now
  1511 contain antiquotations of thm/prop/term/typ/text to be presented
  1512 according to latex print mode; concrete syntax is like this:
  1513 @{term[show_types] "f(x) = a + x"};
  1514 
  1515 * isatool mkdir provides easy setup of Isabelle session directories,
  1516 including proper document sources;
  1517 
  1518 * generated LaTeX sources are now deleted after successful run
  1519 (isatool document -c); may retain a copy somewhere else via -D option
  1520 of isatool usedir;
  1521 
  1522 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1523 style files, achieving self-contained LaTeX sources and simplifying
  1524 LaTeX debugging;
  1525 
  1526 * old-style theories now produce (crude) LaTeX output as well;
  1527 
  1528 * browser info session directories are now self-contained (may be put
  1529 on WWW server seperately); improved graphs of nested sessions; removed
  1530 graph for 'all sessions';
  1531 
  1532 * several improvements in isabelle style files; \isabellestyle{it}
  1533 produces fake math mode output; \isamarkupheader is now \section by
  1534 default; see lib/texinputs/isabelle.sty etc.;
  1535 
  1536 
  1537 *** Isar ***
  1538 
  1539 * Isar/Pure: local results and corresponding term bindings are now
  1540 subject to Hindley-Milner polymorphism (similar to ML); this
  1541 accommodates incremental type-inference very nicely;
  1542 
  1543 * Isar/Pure: new derived language element 'obtain' supports
  1544 generalized existence reasoning;
  1545 
  1546 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1547 support accumulation of results, without applying any rules yet;
  1548 useful to collect intermediate results without explicit name
  1549 references, and for use with transitivity rules with more than 2
  1550 premises;
  1551 
  1552 * Isar/Pure: scalable support for case-analysis type proofs: new
  1553 'case' language element refers to local contexts symbolically, as
  1554 produced by certain proof methods; internally, case names are attached
  1555 to theorems as "tags";
  1556 
  1557 * Isar/Pure: theory command 'hide' removes declarations from
  1558 class/type/const name spaces;
  1559 
  1560 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1561 indicate potential overloading;
  1562 
  1563 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1564 
  1565 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1566 "{a,b,c}" instead of {a,b,c};
  1567 
  1568 * Isar/Pure now provides its own version of intro/elim/dest
  1569 attributes; useful for building new logics, but beware of confusion
  1570 with the version in Provers/classical;
  1571 
  1572 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1573 case name 'antecedent';
  1574 
  1575 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1576 to the current context is now done automatically);
  1577 
  1578 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1579 for definining proof methods in ML;
  1580 
  1581 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1582 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1583 most cases, one should have to change intro!! to intro? only);
  1584 replaced "delrule" by "rule del";
  1585 
  1586 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1587 'symmetric' attribute (the latter supercedes [RS sym]);
  1588 
  1589 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1590 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1591 well (including splits);
  1592 
  1593 * Isar/Provers: Simplifier and Classical methods now support all kind
  1594 of modifiers used in the past, including 'cong', 'iff', etc.
  1595 
  1596 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1597 of Simplifier and Classical reasoner);
  1598 
  1599 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1600 now support named cases; major packages (inductive, datatype, primrec,
  1601 recdef) support case names and properly name parameters;
  1602 
  1603 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1604 monotonicity conditions are extracted to be proven at end of
  1605 calculations;
  1606 
  1607 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1608 method anyway;
  1609 
  1610 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1611 split_if split_if_asm; datatype package provides theorems foo.splits =
  1612 foo.split foo.split_asm for each datatype;
  1613 
  1614 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1615 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1616 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1617 use "(cases (simplified))" method in proper proof texts);
  1618 
  1619 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1620 
  1621 * Isar: names of theorems etc. may be natural numbers as well;
  1622 
  1623 * Isar: 'pr' command: optional arguments for goals_limit and
  1624 ProofContext.prems_limit; no longer prints theory contexts, but only
  1625 proof states;
  1626 
  1627 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1628 additional print modes to be specified; e.g. "pr(latex)" will print
  1629 proof state according to the Isabelle LaTeX style;
  1630 
  1631 * Isar: improved support for emulating tactic scripts, including proof
  1632 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1633 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1634 (for HOL datatypes);
  1635 
  1636 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1637 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1638 'proof method scripts' have to be in depth-first order;
  1639 
  1640 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1641 
  1642 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1643 should instead use individual commands for printing items
  1644 (print_commands, print_methods etc.);
  1645 
  1646 * Isar: added 'nothing' --- the empty list of theorems;
  1647 
  1648 
  1649 *** HOL ***
  1650 
  1651 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1652 corresponding virtual machine and a specification of its bytecode
  1653 verifier and a lightweight bytecode verifier, including proofs of
  1654 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1655 Cornelia Pusch (see also the homepage of project Bali at
  1656 http://isabelle.in.tum.de/Bali/);
  1657 
  1658 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1659 Clemens Ballarin;
  1660 
  1661 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1662 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1663 Rasmussen;
  1664 
  1665 * HOL/Lattice: fundamental concepts of lattice theory and order
  1666 structures, including duals, properties of bounds versus algebraic
  1667 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1668 Theorem for complete lattices etc.; may also serve as a demonstration
  1669 for abstract algebraic reasoning using axiomatic type classes, and
  1670 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1671 
  1672 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1673 von Oheimb;
  1674 
  1675 * HOL/IMPP: extension of IMP with local variables and mutually
  1676 recursive procedures, by David von Oheimb;
  1677 
  1678 * HOL/Lambda: converted into new-style theory and document;
  1679 
  1680 * HOL/ex/Multiquote: example of multiple nested quotations and
  1681 anti-quotations -- basically a generalized version of de-Bruijn
  1682 representation; very useful in avoiding lifting of operations;
  1683 
  1684 * HOL/record: added general record equality rule to simpset; fixed
  1685 select-update simplification procedure to handle extended records as
  1686 well; admit "r" as field name;
  1687 
  1688 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1689 other numeric types and also as the identity of groups, rings, etc.;
  1690 
  1691 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1692 Types nat and int belong to this axclass;
  1693 
  1694 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1695    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1696    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1697   two terms #m*u and #n*u are replaced by #(m+n)*u
  1698     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1699   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1700     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1701 
  1702 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1703 powerful prover for predicate logic but knows nothing of clasets; see
  1704 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1705 
  1706 * HOL: new version of "case_tac" subsumes both boolean case split and
  1707 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1708 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1709 
  1710 * HOL: simplification no longer dives into case-expressions: only the
  1711 selector expression is simplified, but not the remaining arms; to
  1712 enable full simplification of case-expressions for datatype t, you may
  1713 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1714 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1715 
  1716 * HOL/recdef: the recursion equations generated by 'recdef' for
  1717 function 'f' are now called f.simps instead of f.rules; if all
  1718 termination conditions are proved automatically, these simplification
  1719 rules are added to the simpset, as in primrec; rules may be named
  1720 individually as well, resulting in a separate list of theorems for
  1721 each equation;
  1722 
  1723 * HOL/While is a new theory that provides a while-combinator. It
  1724 permits the definition of tail-recursive functions without the
  1725 provision of a termination measure. The latter is necessary once the
  1726 invariant proof rule for while is applied.
  1727 
  1728 * HOL: new (overloaded) notation for the set of elements below/above
  1729 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1730 
  1731 * HOL: theorems impI, allI, ballI bound as "strip";
  1732 
  1733 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1734 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1735 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1736 
  1737 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1738 
  1739 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1740 main HOL, but was unused);
  1741 
  1742 * HOL: fewer consts declared as global (e.g. have to refer to
  1743 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1744 
  1745 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1746 in case of overlap with user translations (e.g. judgements over
  1747 tuples); (note that the underlying logical represenation is still
  1748 bogus);
  1749 
  1750 
  1751 *** ZF ***
  1752 
  1753 * ZF: simplification automatically cancels common terms in arithmetic
  1754 expressions over nat and int;
  1755 
  1756 * ZF: new treatment of nat to minimize type-checking: all operators
  1757 coerce their operands to a natural number using the function natify,
  1758 making the algebraic laws unconditional;
  1759 
  1760 * ZF: as above, for int: operators coerce their operands to an integer
  1761 using the function intify;
  1762 
  1763 * ZF: the integer library now contains many of the usual laws for the
  1764 orderings, including $<=, and monotonicity laws for $+ and $*;
  1765 
  1766 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1767 simplification;
  1768 
  1769 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1770 to the simplifier and classical reasoner simultaneously;
  1771 
  1772 
  1773 *** General ***
  1774 
  1775 * Provers: blast_tac now handles actual object-logic rules as
  1776 assumptions; note that auto_tac uses blast_tac internally as well;
  1777 
  1778 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1779 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1780 
  1781 * Provers: delrules now handles destruct rules as well (no longer need
  1782 explicit make_elim);
  1783 
  1784 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1785   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1786 use instead the strong form,
  1787   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1788 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1789 from destruct-rules;
  1790 
  1791 * Provers: Simplifier.easy_setup provides a fast path to basic
  1792 Simplifier setup for new object-logics;
  1793 
  1794 * Pure: AST translation rules no longer require constant head on LHS;
  1795 
  1796 * Pure: improved name spaces: ambiguous output is qualified; support
  1797 for hiding of names;
  1798 
  1799 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1800 XSYMBOL_HOME; no longer need to do manual configuration in most
  1801 situations;
  1802 
  1803 * system: compression of ML heaps images may now be controlled via -c
  1804 option of isabelle and isatool usedir (currently only observed by
  1805 Poly/ML);
  1806 
  1807 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1808 useful for remote X11);
  1809 
  1810 * system: provide TAGS file for Isabelle sources;
  1811 
  1812 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1813 order;
  1814 
  1815 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1816 timing flag supersedes proof_timing and Toplevel.trace;
  1817 
  1818 * ML: new combinators |>> and |>>> for incremental transformations
  1819 with secondary results (e.g. certain theory extensions):
  1820 
  1821 * ML: PureThy.add_defs gets additional argument to indicate potential
  1822 overloading (usually false);
  1823 
  1824 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1825 results;
  1826 
  1827 
  1828 
  1829 New in Isabelle99 (October 1999)
  1830 --------------------------------
  1831 
  1832 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1833 
  1834 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1835 are no longer simplified.  (This allows the simplifier to unfold recursive
  1836 functional programs.)  To restore the old behaviour, declare
  1837 
  1838     Delcongs [if_weak_cong];
  1839 
  1840 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1841 complement;
  1842 
  1843 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1844 
  1845 * HOL/datatype: mutual_induct_tac no longer exists --
  1846   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1847 
  1848 * HOL/typedef: fixed type inference for representing set; type
  1849 arguments now have to occur explicitly on the rhs as type constraints;
  1850 
  1851 * ZF: The con_defs part of an inductive definition may no longer refer
  1852 to constants declared in the same theory;
  1853 
  1854 * HOL, ZF: the function mk_cases, generated by the inductive
  1855 definition package, has lost an argument.  To simplify its result, it
  1856 uses the default simpset instead of a supplied list of theorems.
  1857 
  1858 * HOL/List: the constructors of type list are now Nil and Cons;
  1859 
  1860 * Simplifier: the type of the infix ML functions
  1861         setSSolver addSSolver setSolver addSolver
  1862 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1863 for packaging solvers. A solver is created via
  1864         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1865 where the string argument is only a comment.
  1866 
  1867 
  1868 *** Proof tools ***
  1869 
  1870 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1871 decision procedure for linear arithmetic. Currently it is used for
  1872 types `nat', `int', and `real' in HOL (see below); it can, should and
  1873 will be instantiated for other types and logics as well.
  1874 
  1875 * The simplifier now accepts rewrite rules with flexible heads, eg
  1876      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1877   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1878   matching.
  1879 
  1880 
  1881 *** General ***
  1882 
  1883 * New Isabelle/Isar subsystem provides an alternative to traditional
  1884 tactical theorem proving; together with the ProofGeneral/isar user
  1885 interface it offers an interactive environment for developing human
  1886 readable proof documents (Isar == Intelligible semi-automated
  1887 reasoning); for further information see isatool doc isar-ref,
  1888 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1889 
  1890 * improved and simplified presentation of theories: better HTML markup
  1891 (including colors), graph views in several sizes; isatool usedir now
  1892 provides a proper interface for user theories (via -P option); actual
  1893 document preparation based on (PDF)LaTeX is available as well (for
  1894 new-style theories only); see isatool doc system for more information;
  1895 
  1896 * native support for Proof General, both for classic Isabelle and
  1897 Isabelle/Isar;
  1898 
  1899 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1900 using the graph browser tool;
  1901 
  1902 * Isabelle manuals now also available as PDF;
  1903 
  1904 * theory loader rewritten from scratch (may not be fully
  1905 bug-compatible); old loadpath variable has been replaced by show_path,
  1906 add_path, del_path, reset_path functions; new operations such as
  1907 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1908 isatool doc ref);
  1909 
  1910 * improved isatool install: option -k creates KDE application icon,
  1911 option -p DIR installs standalone binaries;
  1912 
  1913 * added ML_PLATFORM setting (useful for cross-platform installations);
  1914 more robust handling of platform specific ML images for SML/NJ;
  1915 
  1916 * the settings environment is now statically scoped, i.e. it is never
  1917 created again in sub-processes invoked from isabelle, isatool, or
  1918 Isabelle;
  1919 
  1920 * path element specification '~~' refers to '$ISABELLE_HOME';
  1921 
  1922 * in locales, the "assumes" and "defines" parts may be omitted if
  1923 empty;
  1924 
  1925 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1926 long arrows);
  1927 
  1928 * new print_mode "HTML";
  1929 
  1930 * new flag show_tags controls display of tags of theorems (which are
  1931 basically just comments that may be attached by some tools);
  1932 
  1933 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1934 mode and goal output format:
  1935 
  1936 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1937 244c244
  1938 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1939 ---
  1940 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1941 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1942 181c181
  1943 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1944 ---
  1945 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1946 
  1947 * function bind_thms stores lists of theorems (cf. bind_thm);
  1948 
  1949 * new shorthand tactics ftac, eatac, datac, fatac;
  1950 
  1951 * qed (and friends) now accept "" as result name; in that case the
  1952 theorem is not stored, but proper checks and presentation of the
  1953 result still apply;
  1954 
  1955 * theorem database now also indexes constants "Trueprop", "all",
  1956 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1957 
  1958 
  1959 *** HOL ***
  1960 
  1961 ** HOL arithmetic **
  1962 
  1963 * There are now decision procedures for linear arithmetic over nat and
  1964 int:
  1965 
  1966 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1967 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1968 are treated as atomic; subformulae not involving type `nat' or `int'
  1969 are ignored; quantified subformulae are ignored unless they are
  1970 positive universal or negative existential. The tactic has to be
  1971 invoked by hand and can be a little bit slow. In particular, the
  1972 running time is exponential in the number of occurrences of `min' and
  1973 `max', and `-' on `nat'.
  1974 
  1975 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1976 (negated) (in)equalities among the premises and the conclusion into
  1977 account (i.e. no compound formulae) and does not know about `min' and
  1978 `max', and `-' on `nat'. It is fast and is used automatically by the
  1979 simplifier.
  1980 
  1981 NB: At the moment, these decision procedures do not cope with mixed
  1982 nat/int formulae where the two parts interact, such as `m < n ==>
  1983 int(m) < int(n)'.
  1984 
  1985 * HOL/Numeral provides a generic theory of numerals (encoded
  1986 efficiently as bit strings); setup for types nat/int/real is in place;
  1987 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1988 int, existing theories and proof scripts may require a few additional
  1989 type constraints;
  1990 
  1991 * integer division and remainder can now be performed on constant
  1992 arguments;
  1993 
  1994 * many properties of integer multiplication, division and remainder
  1995 are now available;
  1996 
  1997 * An interface to the Stanford Validity Checker (SVC) is available through the
  1998 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  1999 are proved automatically.  SVC must be installed separately, and its results
  2000 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2001 invocation of the underlying oracle).  For SVC see
  2002   http://verify.stanford.edu/SVC
  2003 
  2004 * IsaMakefile: the HOL-Real target now builds an actual image;
  2005 
  2006 
  2007 ** HOL misc **
  2008 
  2009 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2010 (in Isabelle/Isar) -- by Gertrud Bauer;
  2011 
  2012 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2013 analysis for assembly languages with subtypes;
  2014 
  2015 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2016 -- avoids syntactic ambiguities and treats state, transition, and
  2017 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2018 changed syntax and (many) tactics;
  2019 
  2020 * HOL/inductive: Now also handles more general introduction rules such
  2021   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2022   theorems are now maintained within the theory (maintained via the
  2023   "mono" attribute);
  2024 
  2025 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2026   (using function types) such as
  2027 
  2028   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2029 
  2030 * HOL/record: record_simproc (part of the default simpset) takes care
  2031 of selectors applied to updated records; record_split_tac is no longer
  2032 part of the default claset; update_defs may now be removed from the
  2033 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2034 
  2035   claset_ref () := claset() addSWrapper record_split_wrapper;
  2036   Delsimprocs [record_simproc]
  2037 
  2038 * HOL/typedef: fixed type inference for representing set; type
  2039 arguments now have to occur explicitly on the rhs as type constraints;
  2040 
  2041 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2042 names rather than an ML expression;
  2043 
  2044 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2045 supplied later.  Program schemes can be defined, such as
  2046     "While B C s = (if B s then While B C (C s) else s)"
  2047 where the well-founded relation can be chosen after B and C have been given.
  2048 
  2049 * HOL/List: the constructors of type list are now Nil and Cons;
  2050 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2051 course, ML tools referring to List.list.op # etc. have to be adapted;
  2052 
  2053 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2054 disabled by default; run isabelle with option -m HOL to get back to
  2055 the original Gordon/HOL-style output;
  2056 
  2057 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2058 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2059 
  2060 * HOL basic syntax simplified (more orthogonal): all variants of
  2061 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2062 Eps operator is provided as well: "SOME x. P[x]";
  2063 
  2064 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2065 
  2066 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2067 thus available for user theories;
  2068 
  2069 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2070 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2071 time;
  2072 
  2073 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2074 several times and then mp;
  2075 
  2076 
  2077 *** LK ***
  2078 
  2079 * the notation <<...>> is now available as a notation for sequences of
  2080 formulas;
  2081 
  2082 * the simplifier is now installed
  2083 
  2084 * the axiom system has been generalized (thanks to Soren Heilmann)
  2085 
  2086 * the classical reasoner now has a default rule database
  2087 
  2088 
  2089 *** ZF ***
  2090 
  2091 * new primrec section allows primitive recursive functions to be given
  2092 directly (as in HOL) over datatypes and the natural numbers;
  2093 
  2094 * new tactics induct_tac and exhaust_tac for induction (or case
  2095 analysis) over datatypes and the natural numbers;
  2096 
  2097 * the datatype declaration of type T now defines the recursor T_rec;
  2098 
  2099 * simplification automatically does freeness reasoning for datatype
  2100 constructors;
  2101 
  2102 * automatic type-inference, with AddTCs command to insert new
  2103 type-checking rules;
  2104 
  2105 * datatype introduction rules are now added as Safe Introduction rules
  2106 to the claset;
  2107 
  2108 * the syntax "if P then x else y" is now available in addition to
  2109 if(P,x,y);
  2110 
  2111 
  2112 *** Internal programming interfaces ***
  2113 
  2114 * tuned simplifier trace output; new flag debug_simp;
  2115 
  2116 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2117 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2118 
  2119 * AxClass.axclass_tac lost the theory argument;
  2120 
  2121 * tuned current_goals_markers semantics: begin / end goal avoids
  2122 printing empty lines;
  2123 
  2124 * removed prs and prs_fn hook, which was broken because it did not
  2125 include \n in its semantics, forcing writeln to add one
  2126 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2127 string -> unit if you really want to output text without newline;
  2128 
  2129 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2130 plain output, interface builders may have to enable 'isabelle_font'
  2131 mode to get Isabelle font glyphs as before;
  2132 
  2133 * refined token_translation interface; INCOMPATIBILITY: output length
  2134 now of type real instead of int;
  2135 
  2136 * theory loader actions may be traced via new ThyInfo.add_hook
  2137 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2138 your own database of information attached to *whole* theories -- as
  2139 opposed to intra-theory data slots offered via TheoryDataFun;
  2140 
  2141 * proper handling of dangling sort hypotheses (at last!);
  2142 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2143 extra sort hypotheses that can be witnessed from the type signature;
  2144 the force_strip_shyps flag is gone, any remaining shyps are simply
  2145 left in the theorem (with a warning issued by strip_shyps_warning);
  2146 
  2147 
  2148 
  2149 New in Isabelle98-1 (October 1998)
  2150 ----------------------------------
  2151 
  2152 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2153 
  2154 * several changes of automated proof tools;
  2155 
  2156 * HOL: major changes to the inductive and datatype packages, including
  2157 some minor incompatibilities of theory syntax;
  2158 
  2159 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2160 called `inj_on';
  2161 
  2162 * HOL: removed duplicate thms in Arith:
  2163   less_imp_add_less  should be replaced by  trans_less_add1
  2164   le_imp_add_le      should be replaced by  trans_le_add1
  2165 
  2166 * HOL: unary minus is now overloaded (new type constraints may be
  2167 required);
  2168 
  2169 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2170 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2171 now taken as an integer constant.
  2172 
  2173 * Pure: ML function 'theory_of' renamed to 'theory';
  2174 
  2175 
  2176 *** Proof tools ***
  2177 
  2178 * Simplifier:
  2179   1. Asm_full_simp_tac is now more aggressive.
  2180      1. It will sometimes reorient premises if that increases their power to
  2181         simplify.
  2182      2. It does no longer proceed strictly from left to right but may also
  2183         rotate premises to achieve further simplification.
  2184      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2185      old Asm_full_simp_tac in that it does not rotate premises.
  2186   2. The simplifier now knows a little bit about nat-arithmetic.
  2187 
  2188 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2189 allows for selected deletion of wrappers, by introduction of names for
  2190 wrapper functionals.  This implies that addbefore, addSbefore,
  2191 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2192 and that adding two tactics with the same name overwrites the first
  2193 one (emitting a warning).
  2194   type wrapper = (int -> tactic) -> (int -> tactic)
  2195   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2196   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2197   delWrapper, delSWrapper: claset *  string            -> claset
  2198   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2199 
  2200 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2201 semantics; addbefore now affects only the unsafe part of step_tac
  2202 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2203 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2204 by Force_tac;
  2205 
  2206 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2207 compWrapper; added safe wrapper (and access functions for it);
  2208 
  2209 * HOL/split_all_tac is now much faster and fails if there is nothing
  2210 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2211 and the names of the automatically generated variables have changed.
  2212 split_all_tac has moved within claset() from unsafe wrappers to safe
  2213 wrappers, which means that !!-bound variables are split much more
  2214 aggressively, and safe_tac and clarify_tac now split such variables.
  2215 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2216 Note: the same holds for record_split_tac, which does the job of
  2217 split_all_tac for record fields.
  2218 
  2219 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2220 permanently to the default simpset using Addsplits just like
  2221 Addsimps. They can be removed via Delsplits just like
  2222 Delsimps. Lower-case versions are also available.
  2223 
  2224 * HOL/Simplifier: The rule split_if is now part of the default
  2225 simpset. This means that the simplifier will eliminate all occurrences
  2226 of if-then-else in the conclusion of a goal. To prevent this, you can
  2227 either remove split_if completely from the default simpset by
  2228 `Delsplits [split_if]' or remove it in a specific call of the
  2229 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2230 other case splitting rules to/from the default simpset: every datatype
  2231 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2232 t is the name of the datatype).
  2233 
  2234 * Classical reasoner / Simplifier combination: new force_tac (and
  2235 derivatives Force_tac, force) combines rewriting and classical
  2236 reasoning (and whatever other tools) similarly to auto_tac, but is
  2237 aimed to solve the given subgoal completely.
  2238 
  2239 
  2240 *** General ***
  2241 
  2242 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2243 and `goalw': the theory is no longer needed as an explicit argument -
  2244 the current theory context is used; assumptions are no longer returned
  2245 at the ML-level unless one of them starts with ==> or !!; it is
  2246 recommended to convert to these new commands using isatool fixgoal
  2247 (backup your sources first!);
  2248 
  2249 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2250 the current theory context, and 'theory' to lookup stored theories;
  2251 
  2252 * new theory section 'locale' for declaring constants, assumptions and
  2253 definitions that have local scope;
  2254 
  2255 * new theory section 'nonterminals' for purely syntactic types;
  2256 
  2257 * new theory section 'setup' for generic ML setup functions
  2258 (e.g. package initialization);
  2259 
  2260 * the distribution now includes Isabelle icons: see
  2261 lib/logo/isabelle-{small,tiny}.xpm;
  2262 
  2263 * isatool install - install binaries with absolute references to
  2264 ISABELLE_HOME/bin;
  2265 
  2266 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2267 
  2268 * print mode 'emacs' reserved for Isamode;
  2269 
  2270 * support multiple print (ast) translations per constant name;
  2271 
  2272 * theorems involving oracles are now printed with a suffixed [!];
  2273 
  2274 
  2275 *** HOL ***
  2276 
  2277 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2278 
  2279 * HOL/inductive package reorganized and improved: now supports mutual
  2280 definitions such as
  2281 
  2282   inductive EVEN ODD
  2283     intrs
  2284       null "0 : EVEN"
  2285       oddI "n : EVEN ==> Suc n : ODD"
  2286       evenI "n : ODD ==> Suc n : EVEN"
  2287 
  2288 new theorem list "elims" contains an elimination rule for each of the
  2289 recursive sets; inductive definitions now handle disjunctive premises
  2290 correctly (also ZF);
  2291 
  2292 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2293 "mutual_induct" no longer exists - the induction rule is always
  2294 contained in "induct";
  2295 
  2296 
  2297 * HOL/datatype package re-implemented and greatly improved: now
  2298 supports mutually recursive datatypes such as
  2299 
  2300   datatype
  2301     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2302             | SUM ('a aexp) ('a aexp)
  2303             | DIFF ('a aexp) ('a aexp)
  2304             | NUM 'a
  2305   and
  2306     'a bexp = LESS ('a aexp) ('a aexp)
  2307             | AND ('a bexp) ('a bexp)
  2308             | OR ('a bexp) ('a bexp)
  2309 
  2310 as well as indirectly recursive datatypes such as
  2311 
  2312   datatype
  2313     ('a, 'b) term = Var 'a
  2314                   | App 'b ((('a, 'b) term) list)
  2315 
  2316 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2317 induction on mutually / indirectly recursive datatypes.
  2318 
  2319 Primrec equations are now stored in theory and can be accessed via
  2320 <function_name>.simps.
  2321 
  2322 INCOMPATIBILITIES:
  2323 
  2324   - Theories using datatypes must now have theory Datatype as an
  2325     ancestor.
  2326   - The specific <typename>.induct_tac no longer exists - use the
  2327     generic induct_tac instead.
  2328   - natE has been renamed to nat.exhaust - use exhaust_tac
  2329     instead of res_inst_tac ... natE. Note that the variable
  2330     names in nat.exhaust differ from the names in natE, this
  2331     may cause some "fragile" proofs to fail.
  2332   - The theorems split_<typename>_case and split_<typename>_case_asm
  2333     have been renamed to <typename>.split and <typename>.split_asm.
  2334   - Since default sorts of type variables are now handled correctly,
  2335     some datatype definitions may have to be annotated with explicit
  2336     sort constraints.
  2337   - Primrec definitions no longer require function name and type
  2338     of recursive argument.
  2339 
  2340 Consider using isatool fixdatatype to adapt your theories and proof
  2341 scripts to the new package (backup your sources first!).
  2342 
  2343 
  2344 * HOL/record package: considerably improved implementation; now
  2345 includes concrete syntax for record types, terms, updates; theorems
  2346 for surjective pairing and splitting !!-bound record variables; proof
  2347 support is as follows:
  2348 
  2349   1) standard conversions (selectors or updates applied to record
  2350 constructor terms) are part of the standard simpset;
  2351 
  2352   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2353 made part of standard simpset and claset via addIffs;
  2354 
  2355   3) a tactic for record field splitting (record_split_tac) is part of
  2356 the standard claset (addSWrapper);
  2357 
  2358 To get a better idea about these rules you may retrieve them via
  2359 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2360 the name of your record type.
  2361 
  2362 The split tactic 3) conceptually simplifies by the following rule:
  2363 
  2364   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2365 
  2366 Thus any record variable that is bound by meta-all will automatically
  2367 blow up into some record constructor term, consequently the
  2368 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2369 solve record problems automatically.
  2370 
  2371 
  2372 * reorganized the main HOL image: HOL/Integ and String loaded by
  2373 default; theory Main includes everything;
  2374 
  2375 * automatic simplification of integer sums and comparisons, using cancellation;
  2376 
  2377 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2378 
  2379 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2380 
  2381 * many new identities for unions, intersections, set difference, etc.;
  2382 
  2383 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2384 called split_if, split_split, split_sum_case and split_nat_case (to go
  2385 with add/delsplits);
  2386 
  2387 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2388 (?x::unit) = (); this is made part of the default simpset, which COULD
  2389 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2390 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2391 unit_abs_eta_conv is added in order to counter the effect of
  2392 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2393 %u.f();
  2394 
  2395 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2396 makes more sense);
  2397 
  2398 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2399   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2400   disjointness reasoning but breaking a few old proofs.
  2401 
  2402 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2403 to 'converse' from 'inverse' (for compatibility with ZF and some
  2404 literature);
  2405 
  2406 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2407 the well-founded relation;
  2408 
  2409 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2410     Compl A.  The "Compl" syntax remains available as input syntax for this
  2411     release ONLY.
  2412 
  2413 * HOL/Update: new theory of function updates:
  2414     f(a:=b) == %x. if x=a then b else f x
  2415 may also be iterated as in f(a:=b,c:=d,...);
  2416 
  2417 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2418 
  2419 * HOL/List:
  2420   - new function list_update written xs[i:=v] that updates the i-th
  2421     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2422   - new function `upt' written [i..j(] which generates the list
  2423     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2424     bound write [i..j], which is a shorthand for [i..j+1(].
  2425   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2426 
  2427 * HOL/Arith:
  2428   - removed 'pred' (predecessor) function;
  2429   - generalized some theorems about n-1;
  2430   - many new laws about "div" and "mod";
  2431   - new laws about greatest common divisors (see theory ex/Primes);
  2432 
  2433 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2434 instead of "inverse";
  2435 
  2436 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2437   of the multiset ordering;
  2438 
  2439 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2440   (not included by default);
  2441 
  2442 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2443 
  2444 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2445   programs, i.e. different program variables may have different types.
  2446 
  2447 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2448   [previously, this check worked only if the rewrite rule was unconditional]
  2449   Now rew can involve either definitions or equalities (either == or =).
  2450 
  2451 
  2452 *** ZF ***
  2453 
  2454 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2455   only the theorems proved on ZF.ML;
  2456 
  2457 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2458   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2459   disjointness reasoning but breaking a few old proofs.
  2460 
  2461 * ZF/Update: new theory of function updates
  2462     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2463   may also be iterated as in f(a:=b,c:=d,...);
  2464 
  2465 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2466 
  2467 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2468   [previously, this check worked only if the rewrite rule was unconditional]
  2469   Now rew can involve either definitions or equalities (either == or =).
  2470 
  2471 * case_tac provided for compatibility with HOL
  2472     (like the old excluded_middle_tac, but with subgoals swapped)
  2473 
  2474 
  2475 *** Internal programming interfaces ***
  2476 
  2477 * Pure: several new basic modules made available for general use, see
  2478 also src/Pure/README;
  2479 
  2480 * improved the theory data mechanism to support encapsulation (data
  2481 kind name replaced by private Object.kind, acting as authorization
  2482 key); new type-safe user interface via functor TheoryDataFun; generic
  2483 print_data function becomes basically useless;
  2484 
  2485 * removed global_names compatibility flag -- all theory declarations
  2486 are qualified by default;
  2487 
  2488 * module Pure/Syntax now offers quote / antiquote translation
  2489 functions (useful for Hoare logic etc. with implicit dependencies);
  2490 see HOL/ex/Antiquote for an example use;
  2491 
  2492 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2493 cterm -> thm;
  2494 
  2495 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2496 subgoal;
  2497 
  2498 * Display.print_goals function moved to Locale.print_goals;
  2499 
  2500 * standard print function for goals supports current_goals_markers
  2501 variable for marking begin of proof, end of proof, start of goal; the
  2502 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2503 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2504 for example;
  2505 
  2506 
  2507 
  2508 New in Isabelle98 (January 1998)
  2509 --------------------------------
  2510 
  2511 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2512 
  2513 * changed lexical syntax of terms / types: dots made part of long
  2514 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2515 
  2516 * simpset (and claset) reference variable replaced by functions
  2517 simpset / simpset_ref;
  2518 
  2519 * no longer supports theory aliases (via merge) and non-trivial
  2520 implicit merge of thms' signatures;
  2521 
  2522 * most internal names of constants changed due to qualified names;
  2523 
  2524 * changed Pure/Sequence interface (see Pure/seq.ML);
  2525 
  2526 
  2527 *** General Changes ***
  2528 
  2529 * hierachically structured name spaces (for consts, types, axms, thms
  2530 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2531 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2532 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2533 long_names for fully qualified output names; NOTE: ML programs
  2534 (special tactics, packages etc.) referring to internal names may have
  2535 to be adapted to cope with fully qualified names; in case of severe
  2536 backward campatibility problems try setting 'global_names' at compile
  2537 time to have enrything declared within a flat name space; one may also
  2538 fine tune name declarations in theories via the 'global' and 'local'
  2539 section;
  2540 
  2541 * reimplemented the implicit simpset and claset using the new anytype
  2542 data filed in signatures; references simpset:simpset ref etc. are
  2543 replaced by functions simpset:unit->simpset and
  2544 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2545 to patch your ML files accordingly;
  2546 
  2547 * HTML output now includes theory graph data for display with Java
  2548 applet or isatool browser; data generated automatically via isatool
  2549 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2550 
  2551 * defs may now be conditional; improved rewrite_goals_tac to handle
  2552 conditional equations;
  2553 
  2554 * defs now admits additional type arguments, using TYPE('a) syntax;
  2555 
  2556 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2557 creates a new theory node; implicit merge of thms' signatures is
  2558 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2559 transfer:theory->thm->thm in (rare) cases;
  2560 
  2561 * improved handling of draft signatures / theories; draft thms (and
  2562 ctyps, cterms) are automatically promoted to real ones;
  2563 
  2564 * slightly changed interfaces for oracles: admit many per theory, named
  2565 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2566 
  2567 * print_goals: optional output of const types (set show_consts and
  2568 show_types);
  2569 
  2570 * improved output of warnings (###) and errors (***);
  2571 
  2572 * subgoal_tac displays a warning if the new subgoal has type variables;
  2573 
  2574 * removed old README and Makefiles;
  2575 
  2576 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2577 
  2578 * removed obsolete init_pps and init_database;
  2579 
  2580 * deleted the obsolete tactical STATE, which was declared by
  2581     fun STATE tacfun st = tacfun st st;
  2582 
  2583 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2584 (which abbreviates $HOME);
  2585 
  2586 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2587 use isatool fixseq to adapt your ML programs (this works for fully
  2588 qualified references to the Sequence structure only!);
  2589 
  2590 * use_thy no longer requires writable current directory; it always
  2591 reloads .ML *and* .thy file, if either one is out of date;
  2592 
  2593 
  2594 *** Classical Reasoner ***
  2595 
  2596 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2597 tactics that use classical reasoning to simplify a subgoal without
  2598 splitting it into several subgoals;
  2599 
  2600 * Safe_tac: like safe_tac but uses the default claset;
  2601 
  2602 
  2603 *** Simplifier ***
  2604 
  2605 * added simplification meta rules:
  2606     (asm_)(full_)simplify: simpset -> thm -> thm;
  2607 
  2608 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2609 logics (again);
  2610 
  2611 * added prems argument to simplification procedures;
  2612 
  2613 * HOL, FOL, ZF: added infix function `addsplits':
  2614   instead of `<simpset> setloop (split_tac <thms>)'
  2615   you can simply write `<simpset> addsplits <thms>'
  2616 
  2617 
  2618 *** Syntax ***
  2619 
  2620 * TYPE('a) syntax for type reflection terms;
  2621 
  2622 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2623 
  2624 * pretty printer: changed order of mixfix annotation preference (again!);
  2625 
  2626 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2627 
  2628 
  2629 *** HOL ***
  2630 
  2631 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2632   with `addloop' of the simplifier to faciliate case splitting in premises.
  2633 
  2634 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2635 
  2636 * HOL/Auth: new protocol proofs including some for the Internet
  2637   protocol TLS;
  2638 
  2639 * HOL/Map: new theory of `maps' a la VDM;
  2640 
  2641 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2642 cancelling out common nat summands from =, <, <= (in)equalities, or
  2643 differences; simplification procedures nat_cancel_factor for
  2644 cancelling common factor from =, <, <= (in)equalities over natural
  2645 sums; nat_cancel contains both kinds of procedures, it is installed by
  2646 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2647 
  2648 * HOL/simplifier: terms of the form
  2649   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2650   are rewritten to
  2651   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2652   and those of the form
  2653   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2654   are rewritten to
  2655   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2656 
  2657 * HOL/datatype
  2658   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2659 
  2660   P(t_case f1 ... fn x) =
  2661      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2662         ...
  2663        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2664      )
  2665 
  2666   and a theorem `split_t_case_asm' of the form
  2667 
  2668   P(t_case f1 ... fn x) =
  2669     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2670         ...
  2671        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2672      )
  2673   which can be added to a simpset via `addsplits'. The existing theorems
  2674   expand_list_case and expand_option_case have been renamed to
  2675   split_list_case and split_option_case.
  2676 
  2677 * HOL/Arithmetic:
  2678   - `pred n' is automatically converted to `n-1'.
  2679     Users are strongly encouraged not to use `pred' any longer,
  2680     because it will disappear altogether at some point.
  2681   - Users are strongly encouraged to write "0 < n" rather than
  2682     "n ~= 0". Theorems and proof tools have been modified towards this
  2683     `standard'.
  2684 
  2685 * HOL/Lists:
  2686   the function "set_of_list" has been renamed "set" (and its theorems too);
  2687   the function "nth" now takes its arguments in the reverse order and
  2688   has acquired the infix notation "!" as in "xs!n".
  2689 
  2690 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2691 
  2692 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2693   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2694 
  2695 * HOL/record: extensible records with schematic structural subtyping
  2696 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2697 still lacks various theorems and concrete record syntax;
  2698 
  2699 
  2700 *** HOLCF ***
  2701 
  2702 * removed "axioms" and "generated by" sections;
  2703 
  2704 * replaced "ops" section by extended "consts" section, which is capable of
  2705   handling the continuous function space "->" directly;
  2706 
  2707 * domain package:
  2708   . proves theorems immediately and stores them in the theory,
  2709   . creates hierachical name space,
  2710   . now uses normal mixfix annotations (instead of cinfix...),
  2711   . minor changes to some names and values (for consistency),
  2712   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2713   . separator between mutual domain defs: changed "," to "and",
  2714   . improved handling of sort constraints;  now they have to
  2715     appear on the left-hand side of the equations only;
  2716 
  2717 * fixed LAM <x,y,zs>.b syntax;
  2718 
  2719 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2720 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2721 
  2722 
  2723 *** FOL and ZF ***
  2724 
  2725 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2726   with `addloop' of the simplifier to faciliate case splitting in premises.
  2727 
  2728 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2729 in HOL, they strip ALL and --> from proved theorems;
  2730 
  2731 
  2732 
  2733 New in Isabelle94-8 (May 1997)
  2734 ------------------------------
  2735 
  2736 *** General Changes ***
  2737 
  2738 * new utilities to build / run / maintain Isabelle etc. (in parts
  2739 still somewhat experimental); old Makefiles etc. still functional;
  2740 
  2741 * new 'Isabelle System Manual';
  2742 
  2743 * INSTALL text, together with ./configure and ./build scripts;
  2744 
  2745 * reimplemented type inference for greater efficiency, better error
  2746 messages and clean internal interface;
  2747 
  2748 * prlim command for dealing with lots of subgoals (an easier way of
  2749 setting goals_limit);
  2750 
  2751 
  2752 *** Syntax ***
  2753 
  2754 * supports alternative (named) syntax tables (parser and pretty
  2755 printer); internal interface is provided by add_modesyntax(_i);
  2756 
  2757 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2758 be used in conjunction with the Isabelle symbol font; uses the
  2759 "symbols" syntax table;
  2760 
  2761 * added token_translation interface (may translate name tokens in
  2762 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2763 the current print_mode); IMPORTANT: user print translation functions
  2764 are responsible for marking newly introduced bounds
  2765 (Syntax.mark_boundT);
  2766 
  2767 * token translations for modes "xterm" and "xterm_color" that display
  2768 names in bold, underline etc. or colors (which requires a color
  2769 version of xterm);
  2770 
  2771 * infixes may now be declared with names independent of their syntax;
  2772 
  2773 * added typed_print_translation (like print_translation, but may
  2774 access type of constant);
  2775 
  2776 
  2777 *** Classical Reasoner ***
  2778 
  2779 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2780 some limitations.  Blast_tac...
  2781   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2782   + ignores elimination rules that don't have the correct format
  2783         (the conclusion MUST be a formula variable)
  2784   + ignores types, which can make HOL proofs fail
  2785   + rules must not require higher-order unification, e.g. apply_type in ZF
  2786     [message "Function Var's argument not a bound variable" relates to this]
  2787   + its proof strategy is more general but can actually be slower
  2788 
  2789 * substitution with equality assumptions no longer permutes other
  2790 assumptions;
  2791 
  2792 * minor changes in semantics of addafter (now called addaltern); renamed
  2793 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2794 (and access functions for it);
  2795 
  2796 * improved combination of classical reasoner and simplifier:
  2797   + functions for handling clasimpsets
  2798   + improvement of addss: now the simplifier is called _after_ the
  2799     safe steps.
  2800   + safe variant of addss called addSss: uses safe simplifications
  2801     _during_ the safe steps. It is more complete as it allows multiple
  2802     instantiations of unknowns (e.g. with slow_tac).
  2803 
  2804 *** Simplifier ***
  2805 
  2806 * added interface for simplification procedures (functions that
  2807 produce *proven* rewrite rules on the fly, depending on current
  2808 redex);
  2809 
  2810 * ordering on terms as parameter (used for ordered rewriting);
  2811 
  2812 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2813 
  2814 * the solver is now split into a safe and an unsafe part.
  2815 This should be invisible for the normal user, except that the
  2816 functions setsolver and addsolver have been renamed to setSolver and
  2817 addSolver; added safe_asm_full_simp_tac;
  2818 
  2819 
  2820 *** HOL ***
  2821 
  2822 * a generic induction tactic `induct_tac' which works for all datatypes and
  2823 also for type `nat';
  2824 
  2825 * a generic case distinction tactic `exhaust_tac' which works for all
  2826 datatypes and also for type `nat';
  2827 
  2828 * each datatype comes with a function `size';
  2829 
  2830 * patterns in case expressions allow tuple patterns as arguments to
  2831 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2832 
  2833 * primrec now also works with type nat;
  2834 
  2835 * recdef: a new declaration form, allows general recursive functions to be
  2836 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2837 
  2838 * the constant for negation has been renamed from "not" to "Not" to
  2839 harmonize with FOL, ZF, LK, etc.;
  2840 
  2841 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2842 infinite lists;
  2843 
  2844 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2845 
  2846 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2847 problems in commutative rings, using axiomatic type classes for + and *;
  2848 
  2849 * more examples in HOL/MiniML and HOL/Auth;
  2850 
  2851 * more default rewrite rules for quantifiers, union/intersection;
  2852 
  2853 * a new constant `arbitrary == @x.False';
  2854 
  2855 * HOLCF/IOA replaces old HOL/IOA;
  2856 
  2857 * HOLCF changes: derived all rules and arities
  2858   + axiomatic type classes instead of classes
  2859   + typedef instead of faking type definitions
  2860   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2861   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2862   + eliminated the types void, one, tr
  2863   + use unit lift and bool lift (with translations) instead of one and tr
  2864   + eliminated blift from Lift3.thy (use Def instead of blift)
  2865   all eliminated rules are derived as theorems --> no visible changes ;
  2866 
  2867 
  2868 *** ZF ***
  2869 
  2870 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2871 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2872 as ZF_cs addSIs [equalityI];
  2873 
  2874 
  2875 
  2876 New in Isabelle94-7 (November 96)
  2877 ---------------------------------
  2878 
  2879 * allowing negative levels (as offsets) in prlev and choplev;
  2880 
  2881 * super-linear speedup for large simplifications;
  2882 
  2883 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2884 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2885 FAIL); can suppress it using the command Delsimps (ex_simps @
  2886 all_simps); De Morgan laws are also now included, by default;
  2887 
  2888 * improved printing of ==>  :  ~:
  2889 
  2890 * new object-logic "Sequents" adds linear logic, while replacing LK
  2891 and Modal (thanks to Sara Kalvala);
  2892 
  2893 * HOL/Auth: correctness proofs for authentication protocols;
  2894 
  2895 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2896 examples on HOL/Auth);
  2897 
  2898 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2899 the rewriter and classical reasoner simultaneously;
  2900 
  2901 * function uresult no longer returns theorems in "standard" format;
  2902 regain previous version by: val uresult = standard o uresult;
  2903 
  2904 
  2905 
  2906 New in Isabelle94-6
  2907 -------------------
  2908 
  2909 * oracles -- these establish an interface between Isabelle and trusted
  2910 external reasoners, which may deliver results as theorems;
  2911 
  2912 * proof objects (in particular record all uses of oracles);
  2913 
  2914 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2915 
  2916 * "constdefs" section in theory files;
  2917 
  2918 * "primrec" section (HOL) no longer requires names;
  2919 
  2920 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2921 
  2922 
  2923 
  2924 New in Isabelle94-5
  2925 -------------------
  2926 
  2927 * reduced space requirements;
  2928 
  2929 * automatic HTML generation from theories;
  2930 
  2931 * theory files no longer require "..." (quotes) around most types;
  2932 
  2933 * new examples, including two proofs of the Church-Rosser theorem;
  2934 
  2935 * non-curried (1994) version of HOL is no longer distributed;
  2936 
  2937 
  2938 
  2939 New in Isabelle94-4
  2940 -------------------
  2941 
  2942 * greatly reduced space requirements;
  2943 
  2944 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2945 
  2946 * searchable theorem database (see the section "Retrieving theorems" on
  2947 page 8 of the Reference Manual);
  2948 
  2949 * new examples, including Grabczewski's monumental case study of the
  2950 Axiom of Choice;
  2951 
  2952 * The previous version of HOL renamed to Old_HOL;
  2953 
  2954 * The new version of HOL (previously called CHOL) uses a curried syntax
  2955 for functions.  Application looks like f a b instead of f(a,b);
  2956 
  2957 * Mutually recursive inductive definitions finally work in HOL;
  2958 
  2959 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2960 translates to the operator "split";
  2961 
  2962 
  2963 
  2964 New in Isabelle94-3
  2965 -------------------
  2966 
  2967 * new infix operator, addss, allowing the classical reasoner to
  2968 perform simplification at each step of its search.  Example:
  2969         fast_tac (cs addss ss)
  2970 
  2971 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2972 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2973 look like (a,b) instead of <a,b>;
  2974 
  2975 * PLEASE NOTE: CHOL will eventually replace HOL!
  2976 
  2977 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2978 It translates to the operator "split".  A new theory of integers is available;
  2979 
  2980 * In ZF, integer numerals now denote two's-complement binary integers.
  2981 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2982 
  2983 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2984 of the Axiom of Choice;
  2985 
  2986 
  2987 
  2988 New in Isabelle94-2
  2989 -------------------
  2990 
  2991 * Significantly faster resolution;
  2992 
  2993 * the different sections in a .thy file can now be mixed and repeated
  2994 freely;
  2995 
  2996 * Database of theorems for FOL, HOL and ZF.  New
  2997 commands including qed, qed_goal and bind_thm store theorems in the database.
  2998 
  2999 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3000 a given theory (thms_of), or find out what theory a theorem was proved in
  3001 (theory_of_thm);
  3002 
  3003 * Bugs fixed in the inductive definition and datatype packages;
  3004 
  3005 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3006 and HOL_dup_cs obsolete;
  3007 
  3008 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3009 have been removed;
  3010 
  3011 * Simpler definition of function space in ZF;
  3012 
  3013 * new results about cardinal and ordinal arithmetic in ZF;
  3014 
  3015 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3016 types;
  3017 
  3018 
  3019 $Id$