NEWS
author nipkow
Mon May 23 11:14:58 2005 +0200 (2005-05-23)
changeset 16042 8e15ff79851a
parent 16013 3010430d894d
child 16051 b6a945f205b7
permissions -rw-r--r--
tuned trace info (depth)
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryn>
    13   begin
    14 
    15   optionally also with a "files" section. The syntax
    16 
    17   theory <name> = <theory1> + ... + <theoryn>:
    18 
    19   will still be supported for some time but will eventually disappear.
    20   The syntax of old-style theories has not changed.
    21 
    22 * Theory loader: parent theories can now also be referred to via
    23   relative and absolute paths.
    24 
    25 * Provers/quasi.ML: new transitivity reasoners for transitivity only
    26   and quasi orders.
    27 
    28 * Provers/trancl.ML: new transitivity reasoner for transitive and
    29   reflexive-transitive closure of relations.
    30 
    31 * Provers/blast.ML: new reference depth_limit to make blast's depth
    32   limit (previously hard-coded with a value of 20) user-definable.
    33 
    34 * Provers: new version of the subst method, for single-step rewriting: it now
    35   works in bound variable contexts. New is subst (asm), for rewriting an
    36   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    37   subterm than the original subst method, which is still available under the
    38   name simplesubst.
    39 
    40 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    41   More generally, erule now works even if the major premise of the elimination rule
    42   contains !! or ==>.
    43 
    44 * Pure: considerably improved version of 'constdefs' command.  Now
    45   performs automatic type-inference of declared constants; additional
    46   support for local structure declarations (cf. locales and HOL
    47   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    48   to observe strictly sequential dependencies of definitions within a
    49   single 'constdefs' section; moreover, the declared name needs to be
    50   an identifier.  If all fails, consider to fall back on 'consts' and
    51   'defs' separately.
    52 
    53 * Pure: improved indexed syntax and implicit structures.  First of
    54   all, indexed syntax provides a notational device for subscripted
    55   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    56   expressions.  Secondly, in a local context with structure
    57   declarations, number indexes \<^sub>n or the empty index (default
    58   number 1) refer to a certain fixed variable implicitly; option
    59   show_structs controls printing of implicit structures.  Typical
    60   applications of these concepts involve record types and locales.
    61 
    62 * Pure: clear separation of logical types and nonterminals, where the
    63   latter may only occur in 'syntax' specifications or type
    64   abbreviations.  Before that distinction was only partially
    65   implemented via type class "logic" vs. "{}".  Potential
    66   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    67   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    68   specifications may require further adaption (e.g. Cube/Base.thy).
    69 
    70 * Pure: removed obsolete type class "logic", use the top sort {}
    71   instead.  Note that non-logical types should be declared as
    72   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    73   object-logic specifications.
    74 
    75 * Pure: command 'no_syntax' removes grammar declarations (and
    76   translations) resulting from the given syntax specification, which
    77   is interpreted in the same manner as for the 'syntax' command.
    78 
    79 * Pure: print_tac now outputs the goal through the trace channel.
    80 
    81 * Pure: reference Namespace.unique_names included.  If true the
    82   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    83   yet). If false the first entry wins (as during parsing). Default
    84   value is true.
    85 
    86 * Pure: tuned internal renaming of symbolic identifiers -- attach
    87   primes instead of base 26 numbers.
    88 
    89 * Pure: new flag show_question_marks controls printing of leading
    90   question marks in schematic variable names.
    91 
    92 * Pure: new version of thms_containing that searches for a list of
    93   criteria instead of a list of constants. Known criteria are: intro,
    94   elim, dest, name:string, and any term. Criteria can be preceded by
    95   '-' to select theorems that do not match. Intro, elim, dest select
    96   theorems that match the current goal, name:s selects theorems whose
    97   fully qualified name contain s.  Any other term is interpreted as
    98   pattern and selects all theorem matching the pattern. Available in
    99   ProofGeneral under ProofGeneral -> Find Theorems or C-c C-f.
   100 
   101   Example: C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
   102 
   103   prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   104   matching the current goal as introduction rule and not having "HOL." 
   105   in their name (i.e. not being defined in theory HOL).
   106 
   107 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   108 
   109 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   110   specified in mixfix annotations as "(00...)".
   111 
   112 * Pure/Syntax: 'advanced' translation functions (parse_translation
   113   etc.) may depend on the signature of the theory context being
   114   presently used for parsing/printing, see also isar-ref manual.
   115 
   116 * Pure/Simplifier: you can control the depth to which conditional rewriting
   117   is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth Limit.
   118 
   119 * Pure/Simplifier: simplification procedures may now take the current
   120   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   121   interface), which is very useful for calling the Simplifier
   122   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   123   simprocs is gone -- use prems_of_ss on the simpset instead.
   124   Moreover, the low-level mk_simproc no longer applies Logic.varify
   125   internally, to allow for use in a context of fixed variables.
   126 
   127 * Isar debugging: new reference Toplevel.debug; default false.  Set to
   128   make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   129   
   130 * Locales:
   131   - "includes" disallowed in declaration of named locales (command "locale").
   132   - Fixed parameter management in theorem generation for goals with "includes".
   133     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   134 
   135 * Locales:  new commands for the interpretation of locale expressions
   136   in theories (interpretation) and proof contexts (interpret).  These take an
   137   instantiation of the locale parameters and compute proof obligations from
   138   the instantiated specification.  After the obligations have been discharged,
   139   the instantiated theorems of the locale are added to the theory or proof
   140   context.  Interpretation is smart in that already active interpretations
   141   do not occur in proof obligations, neither are instantiated theorems stored
   142   in duplicate.
   143   Use print_interps to inspect active interpretations of a particular locale.
   144   For details, see the Isar Reference manual.
   145 
   146 * Locales: proper static binding of attribute syntax -- i.e. types /
   147   terms / facts mentioned as arguments are always those of the locale
   148   definition context, independently of the context of later
   149   invocations.  Moreover, locale operations (renaming and type / term
   150   instantiation) are applied to attribute arguments as expected.
   151 
   152   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   153   of actual attributes; rare situations may require Attrib.attribute
   154   to embed those attributes into Attrib.src that lack concrete syntax.
   155 
   156   Attribute implementations need to cooperate properly with the static
   157   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   158   Attrib.XXX_thm etc. already do the right thing without further
   159   intervention.  Only unusual applications -- such as "where" or "of"
   160   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   161   both on the context and the facts involved -- may have to assign
   162   parsed values to argument tokens explicitly.
   163 
   164 * Attributes 'induct' and 'cases': type or set names may now be
   165   locally fixed variables as well.
   166 
   167 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   168   selections of theorems in named facts via indices.
   169 
   170 * Pure: reorganized bootstrapping of the Pure theories; CPure is now
   171   derived from Pure, which contains all common declarations already.
   172   Both theories are defined via plain Isabelle/Isar .thy files.
   173   INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   174   CPure.elim / CPure.dest attributes) now appear in the Pure name
   175   space; use isatool fixcpure to adapt your theory and ML sources.
   176 
   177 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   178   is peformed already.  Object-logics merely need to finish their
   179   initial simpset configuration as before.
   180 
   181 
   182 *** Document preparation ***
   183 
   184 * Several new antiquotation:
   185 
   186   @{term_type term} prints a term with its type annotated;
   187 
   188   @{typeof term} prints the type of a term;
   189 
   190   @{const const} is the same as @{term const}, but checks
   191     that the argument is a known logical constant;
   192 
   193   @{term_style style term} and @{thm_style style thm} print a term or
   194     theorem applying a "style" to it
   195 
   196   Predefined styles are "lhs" and "rhs" printing the lhs/rhs of
   197   definitions, equations, inequations etc. and "conclusion" printing
   198   only the conclusion of a meta-logical statement theorem.  Styles may
   199   be defined via TermStyle.add_style in ML.  See the "LaTeX Sugar"
   200   document for more information.
   201 
   202 * Antiquotations now provide the option 'locale=NAME' to specify an
   203   alternative context used for evaluating and printing the subsequent
   204   argument, as in @{thm [locale=LC] fold_commute}, for example.
   205 
   206 * Commands 'display_drafts' and 'print_drafts' perform simple output
   207   of raw sources.  Only those symbols that do not require additional
   208   LaTeX packages (depending on comments in isabellesym.sty) are
   209   displayed properly, everything else is left verbatim.  We use
   210   isatool display and isatool print as front ends; these are subject
   211   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   212 
   213 * Proof scripts as well as some other commands such as ML or
   214   parse/print_translation can now be hidden in the document.  Hiding
   215   is enabled by default, and can be disabled either via the option '-H
   216   false' of isatool usedir or by resetting the reference variable
   217   IsarOutput.hide_commands. Additional commands to be hidden may be
   218   declared using IsarOutput.add_hidden_commands.
   219 
   220 
   221 *** HOL ***
   222 
   223 * Datatype induction via method `induct' now preserves the name of the
   224   induction variable. For example, when proving P(xs::'a list) by induction
   225   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   226   P(list) ==> P(a#list) as previously.
   227 
   228 * HOL/record: reimplementation of records. Improved scalability for
   229   records with many fields, avoiding performance problems for type
   230   inference. Records are no longer composed of nested field types, but
   231   of nested extension types. Therefore the record type only grows
   232   linear in the number of extensions and not in the number of fields.
   233   The top-level (users) view on records is preserved.  Potential
   234   INCOMPATIBILITY only in strange cases, where the theory depends on
   235   the old record representation. The type generated for a record is
   236   called <record_name>_ext_type.
   237 
   238 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   239   enabled to skip the proofs triggered by a record definition or a
   240   simproc (if quick_and_dirty is enabled). Definitions of large
   241   records can take quite long.
   242 
   243 * HOL/record: "record_upd_simproc" for simplification of multiple
   244   record updates enabled by default.  Moreover, trivial updates are
   245   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   246   occasionally, since simplification is more powerful by default.
   247 
   248 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   249 
   250   syntax (epsilon)
   251     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   252 
   253   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   254   and x-symbol; use option '-m epsilon' to get it actually printed.
   255   Moreover, the mathematically important symbolic identifier
   256   \<epsilon> becomes available as variable, constant etc.
   257 
   258 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   259   Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   260   is \<ge>.
   261 
   262 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}" (and similarly for
   263   "\<in>" instead of ":").
   264 
   265 * HOL/SetInterval: The syntax for open intervals has changed:
   266 
   267   Old         New
   268   {..n(}   -> {..<n}
   269   {)n..}   -> {n<..}
   270   {m..n(}  -> {m..<n}
   271   {)m..n}  -> {m<..n}
   272   {)m..n(} -> {m<..<n}
   273 
   274   The old syntax is still supported but will disappear in the future.
   275   For conversion use the following emacs search and replace patterns:
   276 
   277   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   278   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   279 
   280   They are not perfect but work quite well.
   281 
   282 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   283 
   284   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   285   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   286 
   287   There is new syntax for summation over finite sets:
   288 
   289   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   290   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   291   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   292   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   293 
   294   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   295   now translates into 'setsum' as above.
   296 
   297 * HOL: Finite set induction: In Isar proofs, the insert case is now
   298   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   299 
   300 * HOL/Simplifier:
   301 
   302   - Is now set up to reason about transitivity chains involving "trancl"
   303   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   304   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   305   occasionally as simplification may now solve more goals than previously.
   306 
   307   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   308   all partial orders (class "order"), in particular numbers and sets. For
   309   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   310 
   311   - Simproc for "let x = a in f x"
   312   If a is a free or bound variable or a constant then the let is unfolded.
   313   Otherwise first a is simplified to a', and then f a' is simplified to
   314   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   315   otherwise we unfold the let and arrive at g. The simproc can be 
   316   enabled/disabled by the reference use_let_simproc. Potential
   317   INCOMPATIBILITY since simplification is more powerful by default.
   318 
   319 * HOL: The 'refute' command has been extended to support a much larger
   320   fragment of HOL, including axiomatic type classes, constdefs and typedefs,
   321   inductive datatypes and recursion.
   322 
   323 
   324 *** HOLCF ***
   325 
   326 * HOLCF: discontinued special version of 'constdefs' (which used to
   327   support continuous functions) in favor of the general Pure one with
   328   full type-inference.
   329 
   330 
   331 *** ZF ***
   332 
   333 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   334   First Isomorphism Theorem (on quotienting by the kernel of a
   335   homomorphism).
   336 
   337 * ZF/Simplifier: install second copy of type solver that actually
   338   makes use of TC rules declared to Isar proof contexts (or locales);
   339   the old version is still required for ML proof scripts.
   340 
   341 
   342 *** System ***
   343 
   344 * Allow symlinks to all proper Isabelle executables (Isabelle,
   345   isabelle, isatool etc.).
   346 
   347 * isabelle-process: Poly/ML no longer needs Perl to run an interactive
   348   session.
   349 
   350 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   351   isatool doc, isatool mkdir, display_drafts etc.).
   352 
   353 * isatool usedir: option -f allows specification of the ML file to be
   354   used by Isabelle; default is ROOT.ML.
   355 
   356 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   357   (containing Boolean satisfiability problems) into Isabelle/HOL
   358   theories.
   359 
   360 
   361 *** ML ***
   362 
   363 * Pure/library.ML no longer defines its own option datatype, but uses
   364   that of the SML basis, which has constructors NONE and SOME instead
   365   of None and Some, as well as exception Option.Option instead of
   366   OPTION.  The functions the, if_none, is_some, is_none have been
   367   adapted accordingly, while Option.map replaces apsome.
   368 
   369 * The exception LIST is no more, the standard exceptions Empty and
   370   Subscript, as well as Library.UnequalLengths are used instead.  This
   371   means that function like Library.hd and Library.tl are gone, as the
   372   standard hd and tl functions suffice.
   373 
   374   A number of basic functions are now no longer exported to the ML
   375   toplevel, as they are variants of standard functions.  The following
   376   suggests how one can translate existing code:
   377 
   378     rev_append xs ys = List.revAppend (xs, ys)
   379     nth_elem (i, xs) = List.nth (xs, i)
   380     last_elem xs = List.last xs
   381     flat xss = List.concat xss
   382     seq fs = app fs
   383     partition P xs = List.partition P xs
   384     filter P xs = List.filter P xs
   385     mapfilter f xs = List.mapPartial f xs
   386 
   387 * Pure: output via the Isabelle channels of writeln/warning/error
   388   etc. is now passed through Output.output, with a hook for arbitrary
   389   transformations depending on the print_mode (cf. Output.add_mode --
   390   the first active mode that provides a output function wins).
   391   Already formatted output may be embedded into further text via
   392   Output.raw; the result of Pretty.string_of/str_of and derived
   393   functions (string_of_term/cterm/thm etc.) is already marked raw to
   394   accommodate easy composition of diagnostic messages etc.
   395   Programmers rarely need to care about Output.output or Output.raw at
   396   all, with some notable exceptions: Output.output is required when
   397   bypassing the standard channels (writeln etc.), or in token
   398   translations to produce properly formatted results; Output.raw is
   399   required when capturing already output material that will eventually
   400   be presented to the user a second time.  For the default print mode,
   401   both Output.output and Output.raw have no effect.
   402 
   403 * Provers: Simplifier and Classical Reasoner now support proof context
   404   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   405   components are stored in the theory and patched into the
   406   simpset/claset when used in an Isar proof context.  Context
   407   dependent components are maintained by the following theory
   408   operations:
   409 
   410     Simplifier.add_context_simprocs
   411     Simplifier.del_context_simprocs
   412     Simplifier.set_context_subgoaler
   413     Simplifier.reset_context_subgoaler
   414     Simplifier.add_context_looper
   415     Simplifier.del_context_looper
   416     Simplifier.add_context_unsafe_solver
   417     Simplifier.add_context_safe_solver
   418 
   419     Classical.add_context_safe_wrapper
   420     Classical.del_context_safe_wrapper
   421     Classical.add_context_unsafe_wrapper
   422     Classical.del_context_unsafe_wrapper
   423 
   424   IMPORTANT NOTE: proof tools (methods etc.) need to use
   425   local_simpset_of and local_claset_of to instead of the primitive
   426   Simplifier.get_local_simpset and Classical.get_local_claset,
   427   respectively, in order to see the context dependent fields!
   428 
   429 
   430 
   431 New in Isabelle2004 (April 2004)
   432 --------------------------------
   433 
   434 *** General ***
   435 
   436 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   437   Replaces linorder.ML.
   438 
   439 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   440   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   441   (\<a>...\<z>), are now considered normal letters, and can therefore
   442   be used anywhere where an ASCII letter (a...zA...Z) has until
   443   now. COMPATIBILITY: This obviously changes the parsing of some
   444   terms, especially where a symbol has been used as a binder, say
   445   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   446   as an identifier.  Fix it by inserting a space around former
   447   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   448   existing theory and ML files.
   449 
   450 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   451 
   452 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   453   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   454   a normal (but invisible) letter. For multiple letter subscripts repeat
   455   \<^isub> like this: x\<^isub>1\<^isub>2.
   456 
   457 * Pure: There are now sub-/superscripts that can span more than one
   458   character. Text between \<^bsub> and \<^esub> is set in subscript in
   459   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   460   superscript. The new control characters are not identifier parts.
   461 
   462 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   463   content of "..." to the latex file instead of \isacntrl... . The "..."
   464   may consist of any printable characters excluding the end bracket >.
   465 
   466 * Pure: Using new Isar command "finalconsts" (or the ML functions
   467   Theory.add_finals or Theory.add_finals_i) it is now possible to
   468   declare constants "final", which prevents their being given a definition
   469   later.  It is useful for constants whose behaviour is fixed axiomatically
   470   rather than definitionally, such as the meta-logic connectives.
   471 
   472 * Pure: 'instance' now handles general arities with general sorts
   473   (i.e. intersections of classes),
   474 
   475 * Presentation: generated HTML now uses a CSS style sheet to make layout
   476   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   477   It can be changed to alter the colors/layout of generated pages.
   478 
   479 
   480 *** Isar ***
   481 
   482 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   483   cut_tac, subgoal_tac and thin_tac:
   484   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   485     locales are no longer forced to write Isar proof scripts.
   486     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   487     emulations.
   488   - INCOMPATIBILITY: names of variables to be instantiated may no
   489     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   490     This is consistent with the instantiation attribute "where".
   491 
   492 * Attributes "where" and "of":
   493   - Now take type variables of instantiated theorem into account when reading
   494     the instantiation string.  This fixes a bug that caused instantiated
   495     theorems to have too special types in some circumstances.
   496   - "where" permits explicit instantiations of type variables.
   497 
   498 * Calculation commands "moreover" and "also" no longer interfere with
   499   current facts ("this"), admitting arbitrary combinations with "then"
   500   and derived forms.
   501 
   502 * Locales:
   503   - Goal statements involving the context element "includes" no longer
   504     generate theorems with internal delta predicates (those ending on
   505     "_axioms") in the premise.
   506     Resolve particular premise with <locale>.intro to obtain old form.
   507   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   508     specification and "includes" elements in goal statement.
   509   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   510     [intro?] and [elim?] (respectively) by default.
   511   - Experimental command for instantiation of locales in proof contexts:
   512         instantiate <label>[<attrs>]: <loc>
   513     Instantiates locale <loc> and adds all its theorems to the current context
   514     taking into account their attributes.  Label and attrs are optional
   515     modifiers, like in theorem declarations.  If present, names of
   516     instantiated theorems are qualified with <label>, and the attributes
   517     <attrs> are applied after any attributes these theorems might have already.
   518       If the locale has assumptions, a chained fact of the form
   519     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   520     are derived.  The command does not support old-style locales declared
   521     with "locale (open)".
   522       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   523 
   524 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   525   (Isar) contexts.
   526 
   527 
   528 *** HOL ***
   529 
   530 * Proof import: new image HOL4 contains the imported library from
   531   the HOL4 system with about 2500 theorems. It is imported by
   532   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   533   can be used like any other Isabelle image.  See
   534   HOL/Import/HOL/README for more information.
   535 
   536 * Simplifier:
   537   - Much improved handling of linear and partial orders.
   538     Reasoners for linear and partial orders are set up for type classes
   539     "linorder" and "order" respectively, and are added to the default simpset
   540     as solvers.  This means that the simplifier can build transitivity chains
   541     to solve goals from the assumptions.
   542   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   543     of blast or auto after simplification become unnecessary because the goal
   544     is solved by simplification already.
   545 
   546 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   547     all proved in axiomatic type classes for semirings, rings and fields.
   548 
   549 * Numerics:
   550   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   551     now formalized using the Ring_and_Field theory mentioned above.
   552   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   553     than before, because now they are set up once in a generic manner.
   554   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   555     Look for the general versions in Ring_and_Field (and Power if they concern
   556     exponentiation).
   557 
   558 * Type "rat" of the rational numbers is now available in HOL-Complex.
   559 
   560 * Records:
   561   - Record types are now by default printed with their type abbreviation
   562     instead of the list of all field types. This can be configured via
   563     the reference "print_record_type_abbr".
   564   - Simproc "record_upd_simproc" for simplification of multiple updates added
   565     (not enabled by default).
   566   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   567     EX x. x = sel r to True (not enabled by default).
   568   - Tactic "record_split_simp_tac" to split and simplify records added.
   569 
   570 * 'specification' command added, allowing for definition by
   571   specification.  There is also an 'ax_specification' command that
   572   introduces the new constants axiomatically.
   573 
   574 * arith(_tac) is now able to generate counterexamples for reals as well.
   575 
   576 * HOL-Algebra: new locale "ring" for non-commutative rings.
   577 
   578 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   579   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   580 
   581 * HOL-Matrix: a first theory for matrices in HOL with an application of
   582   matrix theory to linear programming.
   583 
   584 * Unions and Intersections:
   585   The latex output syntax of UN and INT has been changed
   586   from "\Union x \in A. B" to "\Union_{x \in A} B"
   587   i.e. the index formulae has become a subscript.
   588   Similarly for "\Union x. B", and for \Inter instead of \Union.
   589 
   590 * Unions and Intersections over Intervals:
   591   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   592   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   593   like in normal math, and corresponding versions for < and for intersection.
   594 
   595 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   596   lexicographic dictonary ordering has been added as "lexord".
   597 
   598 * ML: the legacy theory structures Int and List have been removed. They had
   599   conflicted with ML Basis Library structures having the same names.
   600 
   601 * 'refute' command added to search for (finite) countermodels.  Only works
   602   for a fragment of HOL.  The installation of an external SAT solver is
   603   highly recommended.  See "HOL/Refute.thy" for details.
   604 
   605 * 'quickcheck' command: Allows to find counterexamples by evaluating
   606   formulae under an assignment of free variables to random values.
   607   In contrast to 'refute', it can deal with inductive datatypes,
   608   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   609   for examples.
   610 
   611 
   612 *** HOLCF ***
   613 
   614 * Streams now come with concatenation and are part of the HOLCF image
   615 
   616 
   617 
   618 New in Isabelle2003 (May 2003)
   619 ------------------------------
   620 
   621 *** General ***
   622 
   623 * Provers/simplifier:
   624 
   625   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   626     Assumptions are now subject to complete mutual simplification,
   627     not just from left to right. The simplifier now preserves
   628     the order of assumptions.
   629 
   630     Potential INCOMPATIBILITY:
   631 
   632     -- simp sometimes diverges where the old version did
   633        not, e.g. invoking simp on the goal
   634 
   635         [| P (f x); y = x; f x = f y |] ==> Q
   636 
   637        now gives rise to the infinite reduction sequence
   638 
   639         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   640 
   641        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   642        kind of problem.
   643 
   644     -- Tactics combining classical reasoner and simplification (such as auto)
   645        are also affected by this change, because many of them rely on
   646        simp. They may sometimes diverge as well or yield a different numbers
   647        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   648        in case of problems. Sometimes subsequent calls to the classical
   649        reasoner will fail because a preceeding call to the simplifier too
   650        eagerly simplified the goal, e.g. deleted redundant premises.
   651 
   652   - The simplifier trace now shows the names of the applied rewrite rules
   653 
   654   - You can limit the number of recursive invocations of the simplifier
   655     during conditional rewriting (where the simplifie tries to solve the
   656     conditions before applying the rewrite rule):
   657     ML "simp_depth_limit := n"
   658     where n is an integer. Thus you can force termination where previously
   659     the simplifier would diverge.
   660 
   661   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   662 
   663   - No longer aborts on failed congruence proof.  Instead, the
   664     congruence is ignored.
   665 
   666 * Pure: New generic framework for extracting programs from constructive
   667   proofs. See HOL/Extraction.thy for an example instantiation, as well
   668   as HOL/Extraction for some case studies.
   669 
   670 * Pure: The main goal of the proof state is no longer shown by default, only
   671 the subgoals. This behaviour is controlled by a new flag.
   672    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   673 (ML: Proof.show_main_goal).
   674 
   675 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   676 rules whose conclusion matches subgoal 1:
   677       PG menu: Isabelle/Isar -> Show me -> matching rules
   678 The rules are ordered by how closely they match the subgoal.
   679 In particular, rules that solve a subgoal outright are displayed first
   680 (or rather last, the way they are printed).
   681 (ML: ProofGeneral.print_intros())
   682 
   683 * Pure: New flag trace_unify_fail causes unification to print
   684 diagnostic information (PG: in trace buffer) when it fails. This is
   685 useful for figuring out why single step proofs like rule, erule or
   686 assumption failed.
   687 
   688 * Pure: Locale specifications now produce predicate definitions
   689 according to the body of text (covering assumptions modulo local
   690 definitions); predicate "loc_axioms" covers newly introduced text,
   691 while "loc" is cumulative wrt. all included locale expressions; the
   692 latter view is presented only on export into the global theory
   693 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   694 on the old view without predicates;
   695 
   696 * Pure: predefined locales "var" and "struct" are useful for sharing
   697 parameters (as in CASL, for example); just specify something like
   698 ``var x + var y + struct M'' as import;
   699 
   700 * Pure: improved thms_containing: proper indexing of facts instead of
   701 raw theorems; check validity of results wrt. current name space;
   702 include local facts of proof configuration (also covers active
   703 locales), cover fixed variables in index; may use "_" in term
   704 specification; an optional limit for the number of printed facts may
   705 be given (the default is 40);
   706 
   707 * Pure: disallow duplicate fact bindings within new-style theory files
   708 (batch-mode only);
   709 
   710 * Provers: improved induct method: assumptions introduced by case
   711 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   712 the goal statement); "foo" still refers to all facts collectively;
   713 
   714 * Provers: the function blast.overloaded has been removed: all constants
   715 are regarded as potentially overloaded, which improves robustness in exchange
   716 for slight decrease in efficiency;
   717 
   718 * Provers/linorder: New generic prover for transitivity reasoning over
   719 linear orders.  Note: this prover is not efficient!
   720 
   721 * Isar: preview of problems to finish 'show' now produce an error
   722 rather than just a warning (in interactive mode);
   723 
   724 
   725 *** HOL ***
   726 
   727 * arith(_tac)
   728 
   729  - Produces a counter example if it cannot prove a goal.
   730    Note that the counter example may be spurious if the goal is not a formula
   731    of quantifier-free linear arithmetic.
   732    In ProofGeneral the counter example appears in the trace buffer.
   733 
   734  - Knows about div k and mod k where k is a numeral of type nat or int.
   735 
   736  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   737    linear arithmetic fails. This takes account of quantifiers and divisibility.
   738    Presburger arithmetic can also be called explicitly via presburger(_tac).
   739 
   740 * simp's arithmetic capabilities have been enhanced a bit: it now
   741 takes ~= in premises into account (by performing a case split);
   742 
   743 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   744 are distributed over a sum of terms;
   745 
   746 * New tactic "trans_tac" and method "trans" instantiate
   747 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   748 "<=", "<" and "=").
   749 
   750 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   751 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   752 
   753 * 'typedef' command has new option "open" to suppress the set
   754 definition;
   755 
   756 * functions Min and Max on finite sets have been introduced (theory
   757 Finite_Set);
   758 
   759 * attribute [symmetric] now works for relations as well; it turns
   760 (x,y) : R^-1 into (y,x) : R, and vice versa;
   761 
   762 * induct over a !!-quantified statement (say !!x1..xn):
   763   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   764 
   765 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   766 %x. None. Warning: empty_def now refers to the previously hidden definition
   767 of the empty set.
   768 
   769 * Algebra: formalization of classical algebra.  Intended as base for
   770 any algebraic development in Isabelle.  Currently covers group theory
   771 (up to Sylow's theorem) and ring theory (Universal Property of
   772 Univariate Polynomials).  Contributions welcome;
   773 
   774 * GroupTheory: deleted, since its material has been moved to Algebra;
   775 
   776 * Complex: new directory of the complex numbers with numeric constants,
   777 nonstandard complex numbers, and some complex analysis, standard and
   778 nonstandard (Jacques Fleuriot);
   779 
   780 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   781 
   782 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   783 Fleuriot);
   784 
   785 * Real/HahnBanach: updated and adapted to locales;
   786 
   787 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   788 Gray and Kramer);
   789 
   790 * UNITY: added the Meier-Sanders theory of progress sets;
   791 
   792 * MicroJava: bytecode verifier and lightweight bytecode verifier
   793 as abstract algorithms, instantiated to the JVM;
   794 
   795 * Bali: Java source language formalization. Type system, operational
   796 semantics, axiomatic semantics. Supported language features:
   797 classes, interfaces, objects,virtual methods, static methods,
   798 static/instance fields, arrays, access modifiers, definite
   799 assignment, exceptions.
   800 
   801 
   802 *** ZF ***
   803 
   804 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   805 universe, etc.);
   806 
   807 * Main ZF: virtually all theories converted to new-style format;
   808 
   809 
   810 *** ML ***
   811 
   812 * Pure: Tactic.prove provides sane interface for internal proofs;
   813 omits the infamous "standard" operation, so this is more appropriate
   814 than prove_goalw_cterm in many situations (e.g. in simprocs);
   815 
   816 * Pure: improved error reporting of simprocs;
   817 
   818 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   819 up simprocs;
   820 
   821 
   822 *** Document preparation ***
   823 
   824 * uses \par instead of \\ for line breaks in theory text. This may
   825 shift some page breaks in large documents. To get the old behaviour
   826 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   827 
   828 * minimized dependencies of isabelle.sty and isabellesym.sty on
   829 other packages
   830 
   831 * \<euro> now needs package babel/greek instead of marvosym (which
   832 broke \Rightarrow)
   833 
   834 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   835 textcomp package)
   836 
   837 
   838 
   839 New in Isabelle2002 (March 2002)
   840 --------------------------------
   841 
   842 *** Document preparation ***
   843 
   844 * greatly simplified document preparation setup, including more
   845 graceful interpretation of isatool usedir -i/-d/-D options, and more
   846 instructive isatool mkdir; users should basically be able to get
   847 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   848 users may run a separate document processing stage manually like this:
   849 "isatool usedir -D output HOL Test && isatool document Test/output";
   850 
   851 * theory dependency graph may now be incorporated into documents;
   852 isatool usedir -g true will produce session_graph.eps/.pdf for use
   853 with \includegraphics of LaTeX;
   854 
   855 * proper spacing of consecutive markup elements, especially text
   856 blocks after section headings;
   857 
   858 * support bold style (for single symbols only), input syntax is like
   859 this: "\<^bold>\<alpha>" or "\<^bold>A";
   860 
   861 * \<bullet> is now output as bold \cdot by default, which looks much
   862 better in printed text;
   863 
   864 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   865 note that these symbols are currently unavailable in Proof General /
   866 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   867 
   868 * isatool latex no longer depends on changed TEXINPUTS, instead
   869 isatool document copies the Isabelle style files to the target
   870 location;
   871 
   872 
   873 *** Isar ***
   874 
   875 * Pure/Provers: improved proof by cases and induction;
   876   - 'case' command admits impromptu naming of parameters (such as
   877     "case (Suc n)");
   878   - 'induct' method divinates rule instantiation from the inductive
   879     claim; no longer requires excessive ?P bindings for proper
   880     instantiation of cases;
   881   - 'induct' method properly enumerates all possibilities of set/type
   882     rules; as a consequence facts may be also passed through *type*
   883     rules without further ado;
   884   - 'induct' method now derives symbolic cases from the *rulified*
   885     rule (before it used to rulify cases stemming from the internal
   886     atomized version); this means that the context of a non-atomic
   887     statement becomes is included in the hypothesis, avoiding the
   888     slightly cumbersome show "PROP ?case" form;
   889   - 'induct' may now use elim-style induction rules without chaining
   890     facts, using ``missing'' premises from the goal state; this allows
   891     rules stemming from inductive sets to be applied in unstructured
   892     scripts, while still benefitting from proper handling of non-atomic
   893     statements; NB: major inductive premises need to be put first, all
   894     the rest of the goal is passed through the induction;
   895   - 'induct' proper support for mutual induction involving non-atomic
   896     rule statements (uses the new concept of simultaneous goals, see
   897     below);
   898   - append all possible rule selections, but only use the first
   899     success (no backtracking);
   900   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   901   - undeclared rule case names default to numbers 1, 2, 3, ...;
   902   - added 'print_induct_rules' (covered by help item in recent Proof
   903     General versions);
   904   - moved induct/cases attributes to Pure, methods to Provers;
   905   - generic method setup instantiated for FOL and HOL;
   906 
   907 * Pure: support multiple simultaneous goal statements, for example
   908 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   909 meta-level mechanism, this acts as if several individual goals had
   910 been stated separately; in particular common proof methods need to be
   911 repeated in order to cover all claims; note that a single elimination
   912 step is *not* sufficient to establish the two conjunctions, so this
   913 fails:
   914 
   915   assume "A & B" then have A and B ..   (*".." fails*)
   916 
   917 better use "obtain" in situations as above; alternative refer to
   918 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   919 
   920 * Pure: proper integration with ``locales''; unlike the original
   921 version by Florian Kammller, Isar locales package high-level proof
   922 contexts rather than raw logical ones (e.g. we admit to include
   923 attributes everywhere); operations on locales include merge and
   924 rename; support for implicit arguments (``structures''); simultaneous
   925 type-inference over imports and text; see also HOL/ex/Locales.thy for
   926 some examples;
   927 
   928 * Pure: the following commands have been ``localized'', supporting a
   929 target locale specification "(in name)": 'lemma', 'theorem',
   930 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   931 stored both within the locale and at the theory level (exported and
   932 qualified by the locale name);
   933 
   934 * Pure: theory goals may now be specified in ``long'' form, with
   935 ad-hoc contexts consisting of arbitrary locale elements. for example
   936 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   937 definitions may be given, too); the result is a meta-level rule with
   938 the context elements being discharged in the obvious way;
   939 
   940 * Pure: new proof command 'using' allows to augment currently used
   941 facts after a goal statement ('using' is syntactically analogous to
   942 'apply', but acts on the goal's facts only); this allows chained facts
   943 to be separated into parts given before and after a claim, as in
   944 ``from a and b have C using d and e <proof>'';
   945 
   946 * Pure: renamed "antecedent" case to "rule_context";
   947 
   948 * Pure: new 'judgment' command records explicit information about the
   949 object-logic embedding (used by several tools internally); no longer
   950 use hard-wired "Trueprop";
   951 
   952 * Pure: added 'corollary' command;
   953 
   954 * Pure: fixed 'token_translation' command;
   955 
   956 * Pure: removed obsolete 'exported' attribute;
   957 
   958 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   959 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   960 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   961 
   962 * Pure: method 'atomize' presents local goal premises as object-level
   963 statements (atomic meta-level propositions); setup controlled via
   964 rewrite rules declarations of 'atomize' attribute; example
   965 application: 'induct' method with proper rule statements in improper
   966 proof *scripts*;
   967 
   968 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   969 now consider the syntactic context of assumptions, giving a better
   970 chance to get type-inference of the arguments right (this is
   971 especially important for locales);
   972 
   973 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   974 mode;
   975 
   976 * Pure/obtain: the formal conclusion "thesis", being marked as
   977 ``internal'', may no longer be reference directly in the text;
   978 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   979 situations;
   980 
   981 * Pure: generic 'sym' attribute which declares a rule both as pure
   982 'elim?' and for the 'symmetric' operation;
   983 
   984 * Pure: marginal comments ``--'' may now occur just anywhere in the
   985 text; the fixed correlation with particular command syntax has been
   986 discontinued;
   987 
   988 * Pure: new method 'rules' is particularly well-suited for proof
   989 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   990 but often produces more compact proof terms with less detours;
   991 
   992 * Pure/Provers/classical: simplified integration with pure rule
   993 attributes and methods; the classical "intro?/elim?/dest?"
   994 declarations coincide with the pure ones; the "rule" method no longer
   995 includes classically swapped intros; "intro" and "elim" methods no
   996 longer pick rules from the context; also got rid of ML declarations
   997 AddXIs/AddXEs/AddXDs; all of this has some potential for
   998 INCOMPATIBILITY;
   999 
  1000 * Provers/classical: attribute 'swapped' produces classical inversions
  1001 of introduction rules;
  1002 
  1003 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1004 rules instead of full simplifier context; 'iff' attribute handles
  1005 conditional rules;
  1006 
  1007 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1008 
  1009 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1010 "(permissive)" option to recover old behavior;
  1011 
  1012 * HOL: 'inductive' no longer features separate (collective) attributes
  1013 for 'intros' (was found too confusing);
  1014 
  1015 * HOL: properly declared induction rules less_induct and
  1016 wf_induct_rule;
  1017 
  1018 
  1019 *** HOL ***
  1020 
  1021 * HOL: moved over to sane numeral syntax; the new policy is as
  1022 follows:
  1023 
  1024   - 0 and 1 are polymorphic constants, which are defined on any
  1025   numeric type (nat, int, real etc.);
  1026 
  1027   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1028   binary representation internally;
  1029 
  1030   - type nat has special constructor Suc, and generally prefers Suc 0
  1031   over 1::nat and Suc (Suc 0) over 2::nat;
  1032 
  1033 This change may cause significant problems of INCOMPATIBILITY; here
  1034 are some hints on converting existing sources:
  1035 
  1036   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1037   entities, so expressions involving "-" (unary or binary minus) need
  1038   to be spaced properly;
  1039 
  1040   - existing occurrences of "1" may need to be constraint "1::nat" or
  1041   even replaced by Suc 0; similar for old "2";
  1042 
  1043   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1044 
  1045   - remove all special provisions on numerals in proofs;
  1046 
  1047 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1048 representation (depends on bin_arith_simps in the default context);
  1049 
  1050 * HOL: symbolic syntax for x^2 (numeral 2);
  1051 
  1052 * HOL: the class of all HOL types is now called "type" rather than
  1053 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1054 in axclass/classes, instance/arities, and (usually rare) occurrences
  1055 in typings (of consts etc.); internally the class is called
  1056 "HOL.type", ML programs should refer to HOLogic.typeS;
  1057 
  1058 * HOL/record package improvements:
  1059   - new derived operations "fields" to build a partial record section,
  1060     "extend" to promote a fixed record to a record scheme, and
  1061     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1062     declared as simp by default;
  1063   - shared operations ("more", "fields", etc.) now need to be always
  1064     qualified) --- potential INCOMPATIBILITY;
  1065   - removed "make_scheme" operations (use "make" with "extend") --
  1066     INCOMPATIBILITY;
  1067   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1068   - provides cases/induct rules for use with corresponding Isar
  1069     methods (for concrete records, record schemes, concrete more
  1070     parts, and schematic more parts -- in that order);
  1071   - internal definitions directly based on a light-weight abstract
  1072     theory of product types over typedef rather than datatype;
  1073 
  1074 * HOL: generic code generator for generating executable ML code from
  1075 specifications; specific support for HOL constructs such as inductive
  1076 datatypes and sets, as well as recursive functions; can be invoked
  1077 via 'generate_code' theory section;
  1078 
  1079 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1080 
  1081 * HOL: consolidated and renamed several theories.  In particular:
  1082         Ord.thy has been absorbed into HOL.thy
  1083         String.thy has been absorbed into List.thy
  1084 
  1085 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1086 (beware of argument permutation!);
  1087 
  1088 * HOL: linorder_less_split superseded by linorder_cases;
  1089 
  1090 * HOL/List: "nodups" renamed to "distinct";
  1091 
  1092 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1093 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1094   - Ex_def has changed, now need to use some_eq_ex
  1095 
  1096 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1097 in this (rare) case use:
  1098 
  1099   delSWrapper "split_all_tac"
  1100   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1101 
  1102 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1103 MAY FAIL;
  1104 
  1105 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1106 Isabelle's type classes, ^ on functions and relations has too general
  1107 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1108 necessary to attach explicit type constraints;
  1109 
  1110 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1111 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1112 renamed accordingly (eg "compI" -> "rel_compI").
  1113 
  1114 * HOL: syntax translations now work properly with numerals and records
  1115 expressions;
  1116 
  1117 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1118 of "lam" -- INCOMPATIBILITY;
  1119 
  1120 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1121 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1122 renamed "Product_Type.unit";
  1123 
  1124 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1125 
  1126 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1127 the "cases" method);
  1128 
  1129 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1130 Florian Kammller);
  1131 
  1132 * HOL/IMP: updated and converted to new-style theory format; several
  1133 parts turned into readable document, with proper Isar proof texts and
  1134 some explanations (by Gerwin Klein);
  1135 
  1136 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1137 
  1138 * HOL-Hyperreal is now a logic image;
  1139 
  1140 
  1141 *** HOLCF ***
  1142 
  1143 * Isar: consts/constdefs supports mixfix syntax for continuous
  1144 operations;
  1145 
  1146 * Isar: domain package adapted to new-style theory format, e.g. see
  1147 HOLCF/ex/Dnat.thy;
  1148 
  1149 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1150 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1151 lift.induct_tac, always use UU instead of Undef;
  1152 
  1153 * HOLCF/IMP: updated and converted to new-style theory;
  1154 
  1155 
  1156 *** ZF ***
  1157 
  1158 * Isar: proper integration of logic-specific tools and packages,
  1159 including theory commands '(co)inductive', '(co)datatype',
  1160 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1161 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1162 
  1163 * theory Main no longer includes AC; for the Axiom of Choice, base
  1164 your theory on Main_ZFC;
  1165 
  1166 * the integer library now covers quotients and remainders, with many
  1167 laws relating division to addition, multiplication, etc.;
  1168 
  1169 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1170 typeless version of the formalism;
  1171 
  1172 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1173 format;
  1174 
  1175 * ZF/Induct: new directory for examples of inductive definitions,
  1176 including theory Multiset for multiset orderings; converted to
  1177 new-style theory format;
  1178 
  1179 * ZF: many new theorems about lists, ordinals, etc.;
  1180 
  1181 
  1182 *** General ***
  1183 
  1184 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1185 variable proof controls level of detail: 0 = no proofs (only oracle
  1186 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1187 also ref manual for further ML interfaces;
  1188 
  1189 * Pure/axclass: removed obsolete ML interface
  1190 goal_subclass/goal_arity;
  1191 
  1192 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1193 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1194 separate tokens, so expressions involving minus need to be spaced
  1195 properly;
  1196 
  1197 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1198 rather than "infixl" or "infixr";
  1199 
  1200 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1201 sort constraint specifications in type inference; e.g. "x::_::foo"
  1202 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1203 type variable);
  1204 
  1205 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1206 control output of nested => (types); the default behavior is
  1207 "type_brackets";
  1208 
  1209 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1210 tokens into AST constants;
  1211 
  1212 * Pure/syntax: prefer later declarations of translations and print
  1213 translation functions; potential INCOMPATIBILITY: need to reverse
  1214 multiple declarations for same syntax element constant;
  1215 
  1216 * Pure/show_hyps reset by default (in accordance to existing Isar
  1217 practice);
  1218 
  1219 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1220 addSafter;
  1221 
  1222 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1223 as well;
  1224 
  1225 * system: tested support for MacOS X; should be able to get Isabelle +
  1226 Proof General to work in a plain Terminal after installing Poly/ML
  1227 (e.g. from the Isabelle distribution area) and GNU bash alone
  1228 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1229 support requires further installations, e.g. from
  1230 http://fink.sourceforge.net/);
  1231 
  1232 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1233 
  1234 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1235 of 40 MB), cf. ML_OPTIONS;
  1236 
  1237 * system: Proof General keywords specification is now part of the
  1238 Isabelle distribution (see etc/isar-keywords.el);
  1239 
  1240 * system: support for persistent Proof General sessions (refrain from
  1241 outdating all loaded theories on startup); user may create writable
  1242 logic images like this: ``isabelle -q HOL Test'';
  1243 
  1244 * system: smart selection of Isabelle process versus Isabelle
  1245 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1246 run both "isabelle" and "Isabelle" even if file names are badly
  1247 damaged (executable inspects the case of the first letter of its own
  1248 name); added separate "isabelle-process" and "isabelle-interface";
  1249 
  1250 * system: refrain from any attempt at filtering input streams; no
  1251 longer support ``8bit'' encoding of old isabelle font, instead proper
  1252 iso-latin characters may now be used; the related isatools
  1253 "symbolinput" and "nonascii" have disappeared as well;
  1254 
  1255 * system: removed old "xterm" interface (the print modes "xterm" and
  1256 "xterm_color" are still available for direct use in a suitable
  1257 terminal);
  1258 
  1259 
  1260 
  1261 New in Isabelle99-2 (February 2001)
  1262 -----------------------------------
  1263 
  1264 *** Overview of INCOMPATIBILITIES ***
  1265 
  1266 * HOL: please note that theories in the Library and elsewhere often use the
  1267 new-style (Isar) format; to refer to their theorems in an ML script you must
  1268 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1269 
  1270 * HOL: inductive package no longer splits induction rule aggressively,
  1271 but only as far as specified by the introductions given; the old
  1272 format may be recovered via ML function complete_split_rule or attribute
  1273 'split_rule (complete)';
  1274 
  1275 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1276 gfp_Tarski to gfp_unfold;
  1277 
  1278 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1279 
  1280 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1281 relation); infix "^^" has been renamed "``"; infix "``" has been
  1282 renamed "`"; "univalent" has been renamed "single_valued";
  1283 
  1284 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1285 operation;
  1286 
  1287 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1288 
  1289 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1290 
  1291 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1292 consequence, it is no longer monotonic wrt. the local goal context
  1293 (which is now passed through the inductive cases);
  1294 
  1295 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1296 \<gg> to \<ggreater>;
  1297 
  1298 
  1299 *** Document preparation ***
  1300 
  1301 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1302 available: are "it" for near math-mode best-style output, "sl" for
  1303 slanted text style, and "tt" for plain type-writer; if no
  1304 \isabellestyle command is given, output is according to slanted
  1305 type-writer);
  1306 
  1307 * support sub/super scripts (for single symbols only), input syntax is
  1308 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1309 
  1310 * some more standard symbols; see Appendix A of the system manual for
  1311 the complete list of symbols defined in isabellesym.sty;
  1312 
  1313 * improved isabelle style files; more abstract symbol implementation
  1314 (should now use \isamath{...} and \isatext{...} in custom symbol
  1315 definitions);
  1316 
  1317 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1318 state; Note that presentation of goal states does not conform to
  1319 actual human-readable proof documents.  Please do not include goal
  1320 states into document output unless you really know what you are doing!
  1321 
  1322 * proper indentation of antiquoted output with proportional LaTeX
  1323 fonts;
  1324 
  1325 * no_document ML operator temporarily disables LaTeX document
  1326 generation;
  1327 
  1328 * isatool unsymbolize tunes sources for plain ASCII communication;
  1329 
  1330 
  1331 *** Isar ***
  1332 
  1333 * Pure: Isar now suffers initial goal statements to contain unbound
  1334 schematic variables (this does not conform to actual readable proof
  1335 documents, due to unpredictable outcome and non-compositional proof
  1336 checking); users who know what they are doing may use schematic goals
  1337 for Prolog-style synthesis of proven results;
  1338 
  1339 * Pure: assumption method (an implicit finishing) now handles actual
  1340 rules as well;
  1341 
  1342 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1343 initial goal, declare "that" only as Pure intro (only for single
  1344 steps); the "that" rule assumption may now be involved in implicit
  1345 finishing, thus ".." becomes a feasible for trivial obtains;
  1346 
  1347 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1348 instance proofs may be performed by "..";
  1349 
  1350 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1351 statements as well;
  1352 
  1353 * Pure: more robust selection of calculational rules;
  1354 
  1355 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1356 rule (as well as the assumption rule);
  1357 
  1358 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1359 lemmas, using the graph browser tool;
  1360 
  1361 * Pure: predict failure of "show" in interactive mode;
  1362 
  1363 * Pure: 'thms_containing' now takes actual terms as arguments;
  1364 
  1365 * HOL: improved method 'induct' --- now handles non-atomic goals
  1366 (potential INCOMPATIBILITY); tuned error handling;
  1367 
  1368 * HOL: cases and induct rules now provide explicit hints about the
  1369 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1370 any remaining facts are inserted into the goal verbatim;
  1371 
  1372 * HOL: local contexts (aka cases) may now contain term bindings as
  1373 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1374 the result to be shown in each case;
  1375 
  1376 * HOL: added 'recdef_tc' command;
  1377 
  1378 * isatool convert assists in eliminating legacy ML scripts;
  1379 
  1380 
  1381 *** HOL ***
  1382 
  1383 * HOL/Library: a collection of generic theories to be used together
  1384 with main HOL; the theory loader path already includes this directory
  1385 by default; the following existing theories have been moved here:
  1386 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1387 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1388 
  1389 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1390 modelling and verification task performed in Isabelle/HOL +
  1391 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1392 
  1393 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1394 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1395 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1396 'domain', this makes the theory consistent with mathematical
  1397 literature;
  1398 
  1399 * HOL basics: added overloaded operations "inverse" and "divide"
  1400 (infix "/"), syntax for generic "abs" operation, generic summation
  1401 operator \<Sum>;
  1402 
  1403 * HOL/typedef: simplified package, provide more useful rules (see also
  1404 HOL/subset.thy);
  1405 
  1406 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1407 now expressed as a proper nested rule (old-style tactic scripts may
  1408 require atomize_strip_tac to cope with non-atomic premises);
  1409 
  1410 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1411 to "split_conv" (old name still available for compatibility);
  1412 
  1413 * HOL: improved concrete syntax for strings (e.g. allows translation
  1414 rules with string literals);
  1415 
  1416 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1417  and Fleuriot's mechanization of analysis, including the transcendental
  1418  functions for the reals;
  1419 
  1420 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1421 
  1422 
  1423 *** CTT ***
  1424 
  1425 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1426 "lam" is displayed as TWO lambda-symbols
  1427 
  1428 * CTT: theory Main now available, containing everything (that is, Bool
  1429 and Arith);
  1430 
  1431 
  1432 *** General ***
  1433 
  1434 * Pure: the Simplifier has been implemented properly as a derived rule
  1435 outside of the actual kernel (at last!); the overall performance
  1436 penalty in practical applications is about 50%, while reliability of
  1437 the Isabelle inference kernel has been greatly improved;
  1438 
  1439 * print modes "brackets" and "no_brackets" control output of nested =>
  1440 (types) and ==> (props); the default behaviour is "brackets";
  1441 
  1442 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1443 as assumptions as well;
  1444 
  1445 * system: support Poly/ML 4.0;
  1446 
  1447 * system: isatool install handles KDE version 1 or 2;
  1448 
  1449 
  1450 
  1451 New in Isabelle99-1 (October 2000)
  1452 ----------------------------------
  1453 
  1454 *** Overview of INCOMPATIBILITIES ***
  1455 
  1456 * HOL: simplification of natural numbers is much changed; to partly
  1457 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1458 issue the following ML commands:
  1459 
  1460   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1461   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1462 
  1463 * HOL: simplification no longer dives into case-expressions; this is
  1464 controlled by "t.weak_case_cong" for each datatype t;
  1465 
  1466 * HOL: nat_less_induct renamed to less_induct;
  1467 
  1468 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1469 fixsome to patch .thy and .ML sources automatically;
  1470 
  1471   select_equality  -> some_equality
  1472   select_eq_Ex     -> some_eq_ex
  1473   selectI2EX       -> someI2_ex
  1474   selectI2         -> someI2
  1475   selectI          -> someI
  1476   select1_equality -> some1_equality
  1477   Eps_sym_eq       -> some_sym_eq_trivial
  1478   Eps_eq           -> some_eq_trivial
  1479 
  1480 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1481 
  1482 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1483 instead);
  1484 
  1485 * HOL: the recursion equations generated by 'recdef' are now called
  1486 f.simps instead of f.rules;
  1487 
  1488 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1489 
  1490 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1491 sometimes be needed;
  1492 
  1493 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1494 
  1495 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1496 
  1497 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1498 product is now "<*>" instead of "Times"; the lexicographic product is
  1499 now "<*lex*>" instead of "**";
  1500 
  1501 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1502 of main HOL, but was unused); better use HOL's datatype package;
  1503 
  1504 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1505 the old syntax may be recovered as follows:
  1506 
  1507   syntax (symbols)
  1508     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1509       (infixl "\\<oplus>" 100)
  1510 
  1511 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1512 
  1513 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1514 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1515 internally;
  1516 
  1517 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1518 changed from A/r to A//r;
  1519 
  1520 * ZF: new treatment of arithmetic (nat & int) may break some old
  1521 proofs;
  1522 
  1523 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1524 rulify -> rule_format, elimify -> elim_format, ...);
  1525 
  1526 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1527 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1528 should have to change intro!! to intro? only); replaced "delrule" by
  1529 "rule del";
  1530 
  1531 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1532 
  1533 * Provers: strengthened force_tac by using new first_best_tac;
  1534 
  1535 * LaTeX document preparation: several changes of isabelle.sty (see
  1536 lib/texinputs);
  1537 
  1538 
  1539 *** Document preparation ***
  1540 
  1541 * formal comments (text blocks etc.) in new-style theories may now
  1542 contain antiquotations of thm/prop/term/typ/text to be presented
  1543 according to latex print mode; concrete syntax is like this:
  1544 @{term[show_types] "f(x) = a + x"};
  1545 
  1546 * isatool mkdir provides easy setup of Isabelle session directories,
  1547 including proper document sources;
  1548 
  1549 * generated LaTeX sources are now deleted after successful run
  1550 (isatool document -c); may retain a copy somewhere else via -D option
  1551 of isatool usedir;
  1552 
  1553 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1554 style files, achieving self-contained LaTeX sources and simplifying
  1555 LaTeX debugging;
  1556 
  1557 * old-style theories now produce (crude) LaTeX output as well;
  1558 
  1559 * browser info session directories are now self-contained (may be put
  1560 on WWW server seperately); improved graphs of nested sessions; removed
  1561 graph for 'all sessions';
  1562 
  1563 * several improvements in isabelle style files; \isabellestyle{it}
  1564 produces fake math mode output; \isamarkupheader is now \section by
  1565 default; see lib/texinputs/isabelle.sty etc.;
  1566 
  1567 
  1568 *** Isar ***
  1569 
  1570 * Isar/Pure: local results and corresponding term bindings are now
  1571 subject to Hindley-Milner polymorphism (similar to ML); this
  1572 accommodates incremental type-inference very nicely;
  1573 
  1574 * Isar/Pure: new derived language element 'obtain' supports
  1575 generalized existence reasoning;
  1576 
  1577 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1578 support accumulation of results, without applying any rules yet;
  1579 useful to collect intermediate results without explicit name
  1580 references, and for use with transitivity rules with more than 2
  1581 premises;
  1582 
  1583 * Isar/Pure: scalable support for case-analysis type proofs: new
  1584 'case' language element refers to local contexts symbolically, as
  1585 produced by certain proof methods; internally, case names are attached
  1586 to theorems as "tags";
  1587 
  1588 * Isar/Pure: theory command 'hide' removes declarations from
  1589 class/type/const name spaces;
  1590 
  1591 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1592 indicate potential overloading;
  1593 
  1594 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1595 
  1596 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1597 "{a,b,c}" instead of {a,b,c};
  1598 
  1599 * Isar/Pure now provides its own version of intro/elim/dest
  1600 attributes; useful for building new logics, but beware of confusion
  1601 with the version in Provers/classical;
  1602 
  1603 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1604 case name 'antecedent';
  1605 
  1606 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1607 to the current context is now done automatically);
  1608 
  1609 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1610 for definining proof methods in ML;
  1611 
  1612 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1613 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1614 most cases, one should have to change intro!! to intro? only);
  1615 replaced "delrule" by "rule del";
  1616 
  1617 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1618 'symmetric' attribute (the latter supercedes [RS sym]);
  1619 
  1620 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1621 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1622 well (including splits);
  1623 
  1624 * Isar/Provers: Simplifier and Classical methods now support all kind
  1625 of modifiers used in the past, including 'cong', 'iff', etc.
  1626 
  1627 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1628 of Simplifier and Classical reasoner);
  1629 
  1630 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1631 now support named cases; major packages (inductive, datatype, primrec,
  1632 recdef) support case names and properly name parameters;
  1633 
  1634 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1635 monotonicity conditions are extracted to be proven at end of
  1636 calculations;
  1637 
  1638 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1639 method anyway;
  1640 
  1641 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1642 split_if split_if_asm; datatype package provides theorems foo.splits =
  1643 foo.split foo.split_asm for each datatype;
  1644 
  1645 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1646 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1647 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1648 use "(cases (simplified))" method in proper proof texts);
  1649 
  1650 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1651 
  1652 * Isar: names of theorems etc. may be natural numbers as well;
  1653 
  1654 * Isar: 'pr' command: optional arguments for goals_limit and
  1655 ProofContext.prems_limit; no longer prints theory contexts, but only
  1656 proof states;
  1657 
  1658 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1659 additional print modes to be specified; e.g. "pr(latex)" will print
  1660 proof state according to the Isabelle LaTeX style;
  1661 
  1662 * Isar: improved support for emulating tactic scripts, including proof
  1663 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1664 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1665 (for HOL datatypes);
  1666 
  1667 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1668 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1669 'proof method scripts' have to be in depth-first order;
  1670 
  1671 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1672 
  1673 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1674 should instead use individual commands for printing items
  1675 (print_commands, print_methods etc.);
  1676 
  1677 * Isar: added 'nothing' --- the empty list of theorems;
  1678 
  1679 
  1680 *** HOL ***
  1681 
  1682 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1683 corresponding virtual machine and a specification of its bytecode
  1684 verifier and a lightweight bytecode verifier, including proofs of
  1685 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1686 Cornelia Pusch (see also the homepage of project Bali at
  1687 http://isabelle.in.tum.de/Bali/);
  1688 
  1689 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1690 Clemens Ballarin;
  1691 
  1692 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1693 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1694 Rasmussen;
  1695 
  1696 * HOL/Lattice: fundamental concepts of lattice theory and order
  1697 structures, including duals, properties of bounds versus algebraic
  1698 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1699 Theorem for complete lattices etc.; may also serve as a demonstration
  1700 for abstract algebraic reasoning using axiomatic type classes, and
  1701 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1702 
  1703 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1704 von Oheimb;
  1705 
  1706 * HOL/IMPP: extension of IMP with local variables and mutually
  1707 recursive procedures, by David von Oheimb;
  1708 
  1709 * HOL/Lambda: converted into new-style theory and document;
  1710 
  1711 * HOL/ex/Multiquote: example of multiple nested quotations and
  1712 anti-quotations -- basically a generalized version of de-Bruijn
  1713 representation; very useful in avoiding lifting of operations;
  1714 
  1715 * HOL/record: added general record equality rule to simpset; fixed
  1716 select-update simplification procedure to handle extended records as
  1717 well; admit "r" as field name;
  1718 
  1719 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1720 other numeric types and also as the identity of groups, rings, etc.;
  1721 
  1722 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1723 Types nat and int belong to this axclass;
  1724 
  1725 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1726    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1727    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1728   two terms #m*u and #n*u are replaced by #(m+n)*u
  1729     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1730   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1731     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1732 
  1733 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1734 powerful prover for predicate logic but knows nothing of clasets; see
  1735 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1736 
  1737 * HOL: new version of "case_tac" subsumes both boolean case split and
  1738 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1739 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1740 
  1741 * HOL: simplification no longer dives into case-expressions: only the
  1742 selector expression is simplified, but not the remaining arms; to
  1743 enable full simplification of case-expressions for datatype t, you may
  1744 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1745 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1746 
  1747 * HOL/recdef: the recursion equations generated by 'recdef' for
  1748 function 'f' are now called f.simps instead of f.rules; if all
  1749 termination conditions are proved automatically, these simplification
  1750 rules are added to the simpset, as in primrec; rules may be named
  1751 individually as well, resulting in a separate list of theorems for
  1752 each equation;
  1753 
  1754 * HOL/While is a new theory that provides a while-combinator. It
  1755 permits the definition of tail-recursive functions without the
  1756 provision of a termination measure. The latter is necessary once the
  1757 invariant proof rule for while is applied.
  1758 
  1759 * HOL: new (overloaded) notation for the set of elements below/above
  1760 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1761 
  1762 * HOL: theorems impI, allI, ballI bound as "strip";
  1763 
  1764 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1765 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1766 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1767 
  1768 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1769 
  1770 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1771 main HOL, but was unused);
  1772 
  1773 * HOL: fewer consts declared as global (e.g. have to refer to
  1774 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1775 
  1776 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1777 in case of overlap with user translations (e.g. judgements over
  1778 tuples); (note that the underlying logical represenation is still
  1779 bogus);
  1780 
  1781 
  1782 *** ZF ***
  1783 
  1784 * ZF: simplification automatically cancels common terms in arithmetic
  1785 expressions over nat and int;
  1786 
  1787 * ZF: new treatment of nat to minimize type-checking: all operators
  1788 coerce their operands to a natural number using the function natify,
  1789 making the algebraic laws unconditional;
  1790 
  1791 * ZF: as above, for int: operators coerce their operands to an integer
  1792 using the function intify;
  1793 
  1794 * ZF: the integer library now contains many of the usual laws for the
  1795 orderings, including $<=, and monotonicity laws for $+ and $*;
  1796 
  1797 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1798 simplification;
  1799 
  1800 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1801 to the simplifier and classical reasoner simultaneously;
  1802 
  1803 
  1804 *** General ***
  1805 
  1806 * Provers: blast_tac now handles actual object-logic rules as
  1807 assumptions; note that auto_tac uses blast_tac internally as well;
  1808 
  1809 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1810 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1811 
  1812 * Provers: delrules now handles destruct rules as well (no longer need
  1813 explicit make_elim);
  1814 
  1815 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1816   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1817 use instead the strong form,
  1818   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1819 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1820 from destruct-rules;
  1821 
  1822 * Provers: Simplifier.easy_setup provides a fast path to basic
  1823 Simplifier setup for new object-logics;
  1824 
  1825 * Pure: AST translation rules no longer require constant head on LHS;
  1826 
  1827 * Pure: improved name spaces: ambiguous output is qualified; support
  1828 for hiding of names;
  1829 
  1830 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1831 XSYMBOL_HOME; no longer need to do manual configuration in most
  1832 situations;
  1833 
  1834 * system: compression of ML heaps images may now be controlled via -c
  1835 option of isabelle and isatool usedir (currently only observed by
  1836 Poly/ML);
  1837 
  1838 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1839 useful for remote X11);
  1840 
  1841 * system: provide TAGS file for Isabelle sources;
  1842 
  1843 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1844 order;
  1845 
  1846 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1847 timing flag supersedes proof_timing and Toplevel.trace;
  1848 
  1849 * ML: new combinators |>> and |>>> for incremental transformations
  1850 with secondary results (e.g. certain theory extensions):
  1851 
  1852 * ML: PureThy.add_defs gets additional argument to indicate potential
  1853 overloading (usually false);
  1854 
  1855 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1856 results;
  1857 
  1858 
  1859 
  1860 New in Isabelle99 (October 1999)
  1861 --------------------------------
  1862 
  1863 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1864 
  1865 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1866 are no longer simplified.  (This allows the simplifier to unfold recursive
  1867 functional programs.)  To restore the old behaviour, declare
  1868 
  1869     Delcongs [if_weak_cong];
  1870 
  1871 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1872 complement;
  1873 
  1874 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1875 
  1876 * HOL/datatype: mutual_induct_tac no longer exists --
  1877   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1878 
  1879 * HOL/typedef: fixed type inference for representing set; type
  1880 arguments now have to occur explicitly on the rhs as type constraints;
  1881 
  1882 * ZF: The con_defs part of an inductive definition may no longer refer
  1883 to constants declared in the same theory;
  1884 
  1885 * HOL, ZF: the function mk_cases, generated by the inductive
  1886 definition package, has lost an argument.  To simplify its result, it
  1887 uses the default simpset instead of a supplied list of theorems.
  1888 
  1889 * HOL/List: the constructors of type list are now Nil and Cons;
  1890 
  1891 * Simplifier: the type of the infix ML functions
  1892         setSSolver addSSolver setSolver addSolver
  1893 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1894 for packaging solvers. A solver is created via
  1895         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1896 where the string argument is only a comment.
  1897 
  1898 
  1899 *** Proof tools ***
  1900 
  1901 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1902 decision procedure for linear arithmetic. Currently it is used for
  1903 types `nat', `int', and `real' in HOL (see below); it can, should and
  1904 will be instantiated for other types and logics as well.
  1905 
  1906 * The simplifier now accepts rewrite rules with flexible heads, eg
  1907      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1908   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1909   matching.
  1910 
  1911 
  1912 *** General ***
  1913 
  1914 * New Isabelle/Isar subsystem provides an alternative to traditional
  1915 tactical theorem proving; together with the ProofGeneral/isar user
  1916 interface it offers an interactive environment for developing human
  1917 readable proof documents (Isar == Intelligible semi-automated
  1918 reasoning); for further information see isatool doc isar-ref,
  1919 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1920 
  1921 * improved and simplified presentation of theories: better HTML markup
  1922 (including colors), graph views in several sizes; isatool usedir now
  1923 provides a proper interface for user theories (via -P option); actual
  1924 document preparation based on (PDF)LaTeX is available as well (for
  1925 new-style theories only); see isatool doc system for more information;
  1926 
  1927 * native support for Proof General, both for classic Isabelle and
  1928 Isabelle/Isar;
  1929 
  1930 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1931 using the graph browser tool;
  1932 
  1933 * Isabelle manuals now also available as PDF;
  1934 
  1935 * theory loader rewritten from scratch (may not be fully
  1936 bug-compatible); old loadpath variable has been replaced by show_path,
  1937 add_path, del_path, reset_path functions; new operations such as
  1938 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1939 isatool doc ref);
  1940 
  1941 * improved isatool install: option -k creates KDE application icon,
  1942 option -p DIR installs standalone binaries;
  1943 
  1944 * added ML_PLATFORM setting (useful for cross-platform installations);
  1945 more robust handling of platform specific ML images for SML/NJ;
  1946 
  1947 * the settings environment is now statically scoped, i.e. it is never
  1948 created again in sub-processes invoked from isabelle, isatool, or
  1949 Isabelle;
  1950 
  1951 * path element specification '~~' refers to '$ISABELLE_HOME';
  1952 
  1953 * in locales, the "assumes" and "defines" parts may be omitted if
  1954 empty;
  1955 
  1956 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1957 long arrows);
  1958 
  1959 * new print_mode "HTML";
  1960 
  1961 * new flag show_tags controls display of tags of theorems (which are
  1962 basically just comments that may be attached by some tools);
  1963 
  1964 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1965 mode and goal output format:
  1966 
  1967 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1968 244c244
  1969 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1970 ---
  1971 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1972 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1973 181c181
  1974 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1975 ---
  1976 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1977 
  1978 * function bind_thms stores lists of theorems (cf. bind_thm);
  1979 
  1980 * new shorthand tactics ftac, eatac, datac, fatac;
  1981 
  1982 * qed (and friends) now accept "" as result name; in that case the
  1983 theorem is not stored, but proper checks and presentation of the
  1984 result still apply;
  1985 
  1986 * theorem database now also indexes constants "Trueprop", "all",
  1987 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1988 
  1989 
  1990 *** HOL ***
  1991 
  1992 ** HOL arithmetic **
  1993 
  1994 * There are now decision procedures for linear arithmetic over nat and
  1995 int:
  1996 
  1997 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1998 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1999 are treated as atomic; subformulae not involving type `nat' or `int'
  2000 are ignored; quantified subformulae are ignored unless they are
  2001 positive universal or negative existential. The tactic has to be
  2002 invoked by hand and can be a little bit slow. In particular, the
  2003 running time is exponential in the number of occurrences of `min' and
  2004 `max', and `-' on `nat'.
  2005 
  2006 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2007 (negated) (in)equalities among the premises and the conclusion into
  2008 account (i.e. no compound formulae) and does not know about `min' and
  2009 `max', and `-' on `nat'. It is fast and is used automatically by the
  2010 simplifier.
  2011 
  2012 NB: At the moment, these decision procedures do not cope with mixed
  2013 nat/int formulae where the two parts interact, such as `m < n ==>
  2014 int(m) < int(n)'.
  2015 
  2016 * HOL/Numeral provides a generic theory of numerals (encoded
  2017 efficiently as bit strings); setup for types nat/int/real is in place;
  2018 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2019 int, existing theories and proof scripts may require a few additional
  2020 type constraints;
  2021 
  2022 * integer division and remainder can now be performed on constant
  2023 arguments;
  2024 
  2025 * many properties of integer multiplication, division and remainder
  2026 are now available;
  2027 
  2028 * An interface to the Stanford Validity Checker (SVC) is available through the
  2029 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2030 are proved automatically.  SVC must be installed separately, and its results
  2031 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2032 invocation of the underlying oracle).  For SVC see
  2033   http://verify.stanford.edu/SVC
  2034 
  2035 * IsaMakefile: the HOL-Real target now builds an actual image;
  2036 
  2037 
  2038 ** HOL misc **
  2039 
  2040 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2041 (in Isabelle/Isar) -- by Gertrud Bauer;
  2042 
  2043 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2044 analysis for assembly languages with subtypes;
  2045 
  2046 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2047 -- avoids syntactic ambiguities and treats state, transition, and
  2048 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2049 changed syntax and (many) tactics;
  2050 
  2051 * HOL/inductive: Now also handles more general introduction rules such
  2052   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2053   theorems are now maintained within the theory (maintained via the
  2054   "mono" attribute);
  2055 
  2056 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2057   (using function types) such as
  2058 
  2059   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2060 
  2061 * HOL/record: record_simproc (part of the default simpset) takes care
  2062 of selectors applied to updated records; record_split_tac is no longer
  2063 part of the default claset; update_defs may now be removed from the
  2064 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2065 
  2066   claset_ref () := claset() addSWrapper record_split_wrapper;
  2067   Delsimprocs [record_simproc]
  2068 
  2069 * HOL/typedef: fixed type inference for representing set; type
  2070 arguments now have to occur explicitly on the rhs as type constraints;
  2071 
  2072 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2073 names rather than an ML expression;
  2074 
  2075 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2076 supplied later.  Program schemes can be defined, such as
  2077     "While B C s = (if B s then While B C (C s) else s)"
  2078 where the well-founded relation can be chosen after B and C have been given.
  2079 
  2080 * HOL/List: the constructors of type list are now Nil and Cons;
  2081 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2082 course, ML tools referring to List.list.op # etc. have to be adapted;
  2083 
  2084 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2085 disabled by default; run isabelle with option -m HOL to get back to
  2086 the original Gordon/HOL-style output;
  2087 
  2088 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2089 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2090 
  2091 * HOL basic syntax simplified (more orthogonal): all variants of
  2092 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2093 Eps operator is provided as well: "SOME x. P[x]";
  2094 
  2095 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2096 
  2097 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2098 thus available for user theories;
  2099 
  2100 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2101 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2102 time;
  2103 
  2104 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2105 several times and then mp;
  2106 
  2107 
  2108 *** LK ***
  2109 
  2110 * the notation <<...>> is now available as a notation for sequences of
  2111 formulas;
  2112 
  2113 * the simplifier is now installed
  2114 
  2115 * the axiom system has been generalized (thanks to Soren Heilmann)
  2116 
  2117 * the classical reasoner now has a default rule database
  2118 
  2119 
  2120 *** ZF ***
  2121 
  2122 * new primrec section allows primitive recursive functions to be given
  2123 directly (as in HOL) over datatypes and the natural numbers;
  2124 
  2125 * new tactics induct_tac and exhaust_tac for induction (or case
  2126 analysis) over datatypes and the natural numbers;
  2127 
  2128 * the datatype declaration of type T now defines the recursor T_rec;
  2129 
  2130 * simplification automatically does freeness reasoning for datatype
  2131 constructors;
  2132 
  2133 * automatic type-inference, with AddTCs command to insert new
  2134 type-checking rules;
  2135 
  2136 * datatype introduction rules are now added as Safe Introduction rules
  2137 to the claset;
  2138 
  2139 * the syntax "if P then x else y" is now available in addition to
  2140 if(P,x,y);
  2141 
  2142 
  2143 *** Internal programming interfaces ***
  2144 
  2145 * tuned simplifier trace output; new flag debug_simp;
  2146 
  2147 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2148 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2149 
  2150 * AxClass.axclass_tac lost the theory argument;
  2151 
  2152 * tuned current_goals_markers semantics: begin / end goal avoids
  2153 printing empty lines;
  2154 
  2155 * removed prs and prs_fn hook, which was broken because it did not
  2156 include \n in its semantics, forcing writeln to add one
  2157 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2158 string -> unit if you really want to output text without newline;
  2159 
  2160 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2161 plain output, interface builders may have to enable 'isabelle_font'
  2162 mode to get Isabelle font glyphs as before;
  2163 
  2164 * refined token_translation interface; INCOMPATIBILITY: output length
  2165 now of type real instead of int;
  2166 
  2167 * theory loader actions may be traced via new ThyInfo.add_hook
  2168 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2169 your own database of information attached to *whole* theories -- as
  2170 opposed to intra-theory data slots offered via TheoryDataFun;
  2171 
  2172 * proper handling of dangling sort hypotheses (at last!);
  2173 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2174 extra sort hypotheses that can be witnessed from the type signature;
  2175 the force_strip_shyps flag is gone, any remaining shyps are simply
  2176 left in the theorem (with a warning issued by strip_shyps_warning);
  2177 
  2178 
  2179 
  2180 New in Isabelle98-1 (October 1998)
  2181 ----------------------------------
  2182 
  2183 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2184 
  2185 * several changes of automated proof tools;
  2186 
  2187 * HOL: major changes to the inductive and datatype packages, including
  2188 some minor incompatibilities of theory syntax;
  2189 
  2190 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2191 called `inj_on';
  2192 
  2193 * HOL: removed duplicate thms in Arith:
  2194   less_imp_add_less  should be replaced by  trans_less_add1
  2195   le_imp_add_le      should be replaced by  trans_le_add1
  2196 
  2197 * HOL: unary minus is now overloaded (new type constraints may be
  2198 required);
  2199 
  2200 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2201 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2202 now taken as an integer constant.
  2203 
  2204 * Pure: ML function 'theory_of' renamed to 'theory';
  2205 
  2206 
  2207 *** Proof tools ***
  2208 
  2209 * Simplifier:
  2210   1. Asm_full_simp_tac is now more aggressive.
  2211      1. It will sometimes reorient premises if that increases their power to
  2212         simplify.
  2213      2. It does no longer proceed strictly from left to right but may also
  2214         rotate premises to achieve further simplification.
  2215      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2216      old Asm_full_simp_tac in that it does not rotate premises.
  2217   2. The simplifier now knows a little bit about nat-arithmetic.
  2218 
  2219 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2220 allows for selected deletion of wrappers, by introduction of names for
  2221 wrapper functionals.  This implies that addbefore, addSbefore,
  2222 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2223 and that adding two tactics with the same name overwrites the first
  2224 one (emitting a warning).
  2225   type wrapper = (int -> tactic) -> (int -> tactic)
  2226   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2227   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2228   delWrapper, delSWrapper: claset *  string            -> claset
  2229   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2230 
  2231 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2232 semantics; addbefore now affects only the unsafe part of step_tac
  2233 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2234 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2235 by Force_tac;
  2236 
  2237 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2238 compWrapper; added safe wrapper (and access functions for it);
  2239 
  2240 * HOL/split_all_tac is now much faster and fails if there is nothing
  2241 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2242 and the names of the automatically generated variables have changed.
  2243 split_all_tac has moved within claset() from unsafe wrappers to safe
  2244 wrappers, which means that !!-bound variables are split much more
  2245 aggressively, and safe_tac and clarify_tac now split such variables.
  2246 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2247 Note: the same holds for record_split_tac, which does the job of
  2248 split_all_tac for record fields.
  2249 
  2250 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2251 permanently to the default simpset using Addsplits just like
  2252 Addsimps. They can be removed via Delsplits just like
  2253 Delsimps. Lower-case versions are also available.
  2254 
  2255 * HOL/Simplifier: The rule split_if is now part of the default
  2256 simpset. This means that the simplifier will eliminate all occurrences
  2257 of if-then-else in the conclusion of a goal. To prevent this, you can
  2258 either remove split_if completely from the default simpset by
  2259 `Delsplits [split_if]' or remove it in a specific call of the
  2260 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2261 other case splitting rules to/from the default simpset: every datatype
  2262 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2263 t is the name of the datatype).
  2264 
  2265 * Classical reasoner / Simplifier combination: new force_tac (and
  2266 derivatives Force_tac, force) combines rewriting and classical
  2267 reasoning (and whatever other tools) similarly to auto_tac, but is
  2268 aimed to solve the given subgoal completely.
  2269 
  2270 
  2271 *** General ***
  2272 
  2273 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2274 and `goalw': the theory is no longer needed as an explicit argument -
  2275 the current theory context is used; assumptions are no longer returned
  2276 at the ML-level unless one of them starts with ==> or !!; it is
  2277 recommended to convert to these new commands using isatool fixgoal
  2278 (backup your sources first!);
  2279 
  2280 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2281 the current theory context, and 'theory' to lookup stored theories;
  2282 
  2283 * new theory section 'locale' for declaring constants, assumptions and
  2284 definitions that have local scope;
  2285 
  2286 * new theory section 'nonterminals' for purely syntactic types;
  2287 
  2288 * new theory section 'setup' for generic ML setup functions
  2289 (e.g. package initialization);
  2290 
  2291 * the distribution now includes Isabelle icons: see
  2292 lib/logo/isabelle-{small,tiny}.xpm;
  2293 
  2294 * isatool install - install binaries with absolute references to
  2295 ISABELLE_HOME/bin;
  2296 
  2297 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2298 
  2299 * print mode 'emacs' reserved for Isamode;
  2300 
  2301 * support multiple print (ast) translations per constant name;
  2302 
  2303 * theorems involving oracles are now printed with a suffixed [!];
  2304 
  2305 
  2306 *** HOL ***
  2307 
  2308 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2309 
  2310 * HOL/inductive package reorganized and improved: now supports mutual
  2311 definitions such as
  2312 
  2313   inductive EVEN ODD
  2314     intrs
  2315       null "0 : EVEN"
  2316       oddI "n : EVEN ==> Suc n : ODD"
  2317       evenI "n : ODD ==> Suc n : EVEN"
  2318 
  2319 new theorem list "elims" contains an elimination rule for each of the
  2320 recursive sets; inductive definitions now handle disjunctive premises
  2321 correctly (also ZF);
  2322 
  2323 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2324 "mutual_induct" no longer exists - the induction rule is always
  2325 contained in "induct";
  2326 
  2327 
  2328 * HOL/datatype package re-implemented and greatly improved: now
  2329 supports mutually recursive datatypes such as
  2330 
  2331   datatype
  2332     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2333             | SUM ('a aexp) ('a aexp)
  2334             | DIFF ('a aexp) ('a aexp)
  2335             | NUM 'a
  2336   and
  2337     'a bexp = LESS ('a aexp) ('a aexp)
  2338             | AND ('a bexp) ('a bexp)
  2339             | OR ('a bexp) ('a bexp)
  2340 
  2341 as well as indirectly recursive datatypes such as
  2342 
  2343   datatype
  2344     ('a, 'b) term = Var 'a
  2345                   | App 'b ((('a, 'b) term) list)
  2346 
  2347 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2348 induction on mutually / indirectly recursive datatypes.
  2349 
  2350 Primrec equations are now stored in theory and can be accessed via
  2351 <function_name>.simps.
  2352 
  2353 INCOMPATIBILITIES:
  2354 
  2355   - Theories using datatypes must now have theory Datatype as an
  2356     ancestor.
  2357   - The specific <typename>.induct_tac no longer exists - use the
  2358     generic induct_tac instead.
  2359   - natE has been renamed to nat.exhaust - use exhaust_tac
  2360     instead of res_inst_tac ... natE. Note that the variable
  2361     names in nat.exhaust differ from the names in natE, this
  2362     may cause some "fragile" proofs to fail.
  2363   - The theorems split_<typename>_case and split_<typename>_case_asm
  2364     have been renamed to <typename>.split and <typename>.split_asm.
  2365   - Since default sorts of type variables are now handled correctly,
  2366     some datatype definitions may have to be annotated with explicit
  2367     sort constraints.
  2368   - Primrec definitions no longer require function name and type
  2369     of recursive argument.
  2370 
  2371 Consider using isatool fixdatatype to adapt your theories and proof
  2372 scripts to the new package (backup your sources first!).
  2373 
  2374 
  2375 * HOL/record package: considerably improved implementation; now
  2376 includes concrete syntax for record types, terms, updates; theorems
  2377 for surjective pairing and splitting !!-bound record variables; proof
  2378 support is as follows:
  2379 
  2380   1) standard conversions (selectors or updates applied to record
  2381 constructor terms) are part of the standard simpset;
  2382 
  2383   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2384 made part of standard simpset and claset via addIffs;
  2385 
  2386   3) a tactic for record field splitting (record_split_tac) is part of
  2387 the standard claset (addSWrapper);
  2388 
  2389 To get a better idea about these rules you may retrieve them via
  2390 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2391 the name of your record type.
  2392 
  2393 The split tactic 3) conceptually simplifies by the following rule:
  2394 
  2395   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2396 
  2397 Thus any record variable that is bound by meta-all will automatically
  2398 blow up into some record constructor term, consequently the
  2399 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2400 solve record problems automatically.
  2401 
  2402 
  2403 * reorganized the main HOL image: HOL/Integ and String loaded by
  2404 default; theory Main includes everything;
  2405 
  2406 * automatic simplification of integer sums and comparisons, using cancellation;
  2407 
  2408 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2409 
  2410 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2411 
  2412 * many new identities for unions, intersections, set difference, etc.;
  2413 
  2414 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2415 called split_if, split_split, split_sum_case and split_nat_case (to go
  2416 with add/delsplits);
  2417 
  2418 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2419 (?x::unit) = (); this is made part of the default simpset, which COULD
  2420 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2421 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2422 unit_abs_eta_conv is added in order to counter the effect of
  2423 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2424 %u.f();
  2425 
  2426 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2427 makes more sense);
  2428 
  2429 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2430   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2431   disjointness reasoning but breaking a few old proofs.
  2432 
  2433 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2434 to 'converse' from 'inverse' (for compatibility with ZF and some
  2435 literature);
  2436 
  2437 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2438 the well-founded relation;
  2439 
  2440 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2441     Compl A.  The "Compl" syntax remains available as input syntax for this
  2442     release ONLY.
  2443 
  2444 * HOL/Update: new theory of function updates:
  2445     f(a:=b) == %x. if x=a then b else f x
  2446 may also be iterated as in f(a:=b,c:=d,...);
  2447 
  2448 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2449 
  2450 * HOL/List:
  2451   - new function list_update written xs[i:=v] that updates the i-th
  2452     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2453   - new function `upt' written [i..j(] which generates the list
  2454     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2455     bound write [i..j], which is a shorthand for [i..j+1(].
  2456   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2457 
  2458 * HOL/Arith:
  2459   - removed 'pred' (predecessor) function;
  2460   - generalized some theorems about n-1;
  2461   - many new laws about "div" and "mod";
  2462   - new laws about greatest common divisors (see theory ex/Primes);
  2463 
  2464 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2465 instead of "inverse";
  2466 
  2467 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2468   of the multiset ordering;
  2469 
  2470 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2471   (not included by default);
  2472 
  2473 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2474 
  2475 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2476   programs, i.e. different program variables may have different types.
  2477 
  2478 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2479   [previously, this check worked only if the rewrite rule was unconditional]
  2480   Now rew can involve either definitions or equalities (either == or =).
  2481 
  2482 
  2483 *** ZF ***
  2484 
  2485 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2486   only the theorems proved on ZF.ML;
  2487 
  2488 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2489   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2490   disjointness reasoning but breaking a few old proofs.
  2491 
  2492 * ZF/Update: new theory of function updates
  2493     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2494   may also be iterated as in f(a:=b,c:=d,...);
  2495 
  2496 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2497 
  2498 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2499   [previously, this check worked only if the rewrite rule was unconditional]
  2500   Now rew can involve either definitions or equalities (either == or =).
  2501 
  2502 * case_tac provided for compatibility with HOL
  2503     (like the old excluded_middle_tac, but with subgoals swapped)
  2504 
  2505 
  2506 *** Internal programming interfaces ***
  2507 
  2508 * Pure: several new basic modules made available for general use, see
  2509 also src/Pure/README;
  2510 
  2511 * improved the theory data mechanism to support encapsulation (data
  2512 kind name replaced by private Object.kind, acting as authorization
  2513 key); new type-safe user interface via functor TheoryDataFun; generic
  2514 print_data function becomes basically useless;
  2515 
  2516 * removed global_names compatibility flag -- all theory declarations
  2517 are qualified by default;
  2518 
  2519 * module Pure/Syntax now offers quote / antiquote translation
  2520 functions (useful for Hoare logic etc. with implicit dependencies);
  2521 see HOL/ex/Antiquote for an example use;
  2522 
  2523 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2524 cterm -> thm;
  2525 
  2526 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2527 subgoal;
  2528 
  2529 * Display.print_goals function moved to Locale.print_goals;
  2530 
  2531 * standard print function for goals supports current_goals_markers
  2532 variable for marking begin of proof, end of proof, start of goal; the
  2533 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2534 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2535 for example;
  2536 
  2537 
  2538 
  2539 New in Isabelle98 (January 1998)
  2540 --------------------------------
  2541 
  2542 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2543 
  2544 * changed lexical syntax of terms / types: dots made part of long
  2545 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2546 
  2547 * simpset (and claset) reference variable replaced by functions
  2548 simpset / simpset_ref;
  2549 
  2550 * no longer supports theory aliases (via merge) and non-trivial
  2551 implicit merge of thms' signatures;
  2552 
  2553 * most internal names of constants changed due to qualified names;
  2554 
  2555 * changed Pure/Sequence interface (see Pure/seq.ML);
  2556 
  2557 
  2558 *** General Changes ***
  2559 
  2560 * hierachically structured name spaces (for consts, types, axms, thms
  2561 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2562 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2563 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2564 long_names for fully qualified output names; NOTE: ML programs
  2565 (special tactics, packages etc.) referring to internal names may have
  2566 to be adapted to cope with fully qualified names; in case of severe
  2567 backward campatibility problems try setting 'global_names' at compile
  2568 time to have enrything declared within a flat name space; one may also
  2569 fine tune name declarations in theories via the 'global' and 'local'
  2570 section;
  2571 
  2572 * reimplemented the implicit simpset and claset using the new anytype
  2573 data filed in signatures; references simpset:simpset ref etc. are
  2574 replaced by functions simpset:unit->simpset and
  2575 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2576 to patch your ML files accordingly;
  2577 
  2578 * HTML output now includes theory graph data for display with Java
  2579 applet or isatool browser; data generated automatically via isatool
  2580 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2581 
  2582 * defs may now be conditional; improved rewrite_goals_tac to handle
  2583 conditional equations;
  2584 
  2585 * defs now admits additional type arguments, using TYPE('a) syntax;
  2586 
  2587 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2588 creates a new theory node; implicit merge of thms' signatures is
  2589 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2590 transfer:theory->thm->thm in (rare) cases;
  2591 
  2592 * improved handling of draft signatures / theories; draft thms (and
  2593 ctyps, cterms) are automatically promoted to real ones;
  2594 
  2595 * slightly changed interfaces for oracles: admit many per theory, named
  2596 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2597 
  2598 * print_goals: optional output of const types (set show_consts and
  2599 show_types);
  2600 
  2601 * improved output of warnings (###) and errors (***);
  2602 
  2603 * subgoal_tac displays a warning if the new subgoal has type variables;
  2604 
  2605 * removed old README and Makefiles;
  2606 
  2607 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2608 
  2609 * removed obsolete init_pps and init_database;
  2610 
  2611 * deleted the obsolete tactical STATE, which was declared by
  2612     fun STATE tacfun st = tacfun st st;
  2613 
  2614 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2615 (which abbreviates $HOME);
  2616 
  2617 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2618 use isatool fixseq to adapt your ML programs (this works for fully
  2619 qualified references to the Sequence structure only!);
  2620 
  2621 * use_thy no longer requires writable current directory; it always
  2622 reloads .ML *and* .thy file, if either one is out of date;
  2623 
  2624 
  2625 *** Classical Reasoner ***
  2626 
  2627 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2628 tactics that use classical reasoning to simplify a subgoal without
  2629 splitting it into several subgoals;
  2630 
  2631 * Safe_tac: like safe_tac but uses the default claset;
  2632 
  2633 
  2634 *** Simplifier ***
  2635 
  2636 * added simplification meta rules:
  2637     (asm_)(full_)simplify: simpset -> thm -> thm;
  2638 
  2639 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2640 logics (again);
  2641 
  2642 * added prems argument to simplification procedures;
  2643 
  2644 * HOL, FOL, ZF: added infix function `addsplits':
  2645   instead of `<simpset> setloop (split_tac <thms>)'
  2646   you can simply write `<simpset> addsplits <thms>'
  2647 
  2648 
  2649 *** Syntax ***
  2650 
  2651 * TYPE('a) syntax for type reflection terms;
  2652 
  2653 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2654 
  2655 * pretty printer: changed order of mixfix annotation preference (again!);
  2656 
  2657 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2658 
  2659 
  2660 *** HOL ***
  2661 
  2662 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2663   with `addloop' of the simplifier to faciliate case splitting in premises.
  2664 
  2665 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2666 
  2667 * HOL/Auth: new protocol proofs including some for the Internet
  2668   protocol TLS;
  2669 
  2670 * HOL/Map: new theory of `maps' a la VDM;
  2671 
  2672 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2673 cancelling out common nat summands from =, <, <= (in)equalities, or
  2674 differences; simplification procedures nat_cancel_factor for
  2675 cancelling common factor from =, <, <= (in)equalities over natural
  2676 sums; nat_cancel contains both kinds of procedures, it is installed by
  2677 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2678 
  2679 * HOL/simplifier: terms of the form
  2680   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2681   are rewritten to
  2682   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2683   and those of the form
  2684   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2685   are rewritten to
  2686   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2687 
  2688 * HOL/datatype
  2689   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2690 
  2691   P(t_case f1 ... fn x) =
  2692      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2693         ...
  2694        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2695      )
  2696 
  2697   and a theorem `split_t_case_asm' of the form
  2698 
  2699   P(t_case f1 ... fn x) =
  2700     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2701         ...
  2702        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2703      )
  2704   which can be added to a simpset via `addsplits'. The existing theorems
  2705   expand_list_case and expand_option_case have been renamed to
  2706   split_list_case and split_option_case.
  2707 
  2708 * HOL/Arithmetic:
  2709   - `pred n' is automatically converted to `n-1'.
  2710     Users are strongly encouraged not to use `pred' any longer,
  2711     because it will disappear altogether at some point.
  2712   - Users are strongly encouraged to write "0 < n" rather than
  2713     "n ~= 0". Theorems and proof tools have been modified towards this
  2714     `standard'.
  2715 
  2716 * HOL/Lists:
  2717   the function "set_of_list" has been renamed "set" (and its theorems too);
  2718   the function "nth" now takes its arguments in the reverse order and
  2719   has acquired the infix notation "!" as in "xs!n".
  2720 
  2721 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2722 
  2723 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2724   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2725 
  2726 * HOL/record: extensible records with schematic structural subtyping
  2727 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2728 still lacks various theorems and concrete record syntax;
  2729 
  2730 
  2731 *** HOLCF ***
  2732 
  2733 * removed "axioms" and "generated by" sections;
  2734 
  2735 * replaced "ops" section by extended "consts" section, which is capable of
  2736   handling the continuous function space "->" directly;
  2737 
  2738 * domain package:
  2739   . proves theorems immediately and stores them in the theory,
  2740   . creates hierachical name space,
  2741   . now uses normal mixfix annotations (instead of cinfix...),
  2742   . minor changes to some names and values (for consistency),
  2743   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2744   . separator between mutual domain defs: changed "," to "and",
  2745   . improved handling of sort constraints;  now they have to
  2746     appear on the left-hand side of the equations only;
  2747 
  2748 * fixed LAM <x,y,zs>.b syntax;
  2749 
  2750 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2751 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2752 
  2753 
  2754 *** FOL and ZF ***
  2755 
  2756 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2757   with `addloop' of the simplifier to faciliate case splitting in premises.
  2758 
  2759 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2760 in HOL, they strip ALL and --> from proved theorems;
  2761 
  2762 
  2763 
  2764 New in Isabelle94-8 (May 1997)
  2765 ------------------------------
  2766 
  2767 *** General Changes ***
  2768 
  2769 * new utilities to build / run / maintain Isabelle etc. (in parts
  2770 still somewhat experimental); old Makefiles etc. still functional;
  2771 
  2772 * new 'Isabelle System Manual';
  2773 
  2774 * INSTALL text, together with ./configure and ./build scripts;
  2775 
  2776 * reimplemented type inference for greater efficiency, better error
  2777 messages and clean internal interface;
  2778 
  2779 * prlim command for dealing with lots of subgoals (an easier way of
  2780 setting goals_limit);
  2781 
  2782 
  2783 *** Syntax ***
  2784 
  2785 * supports alternative (named) syntax tables (parser and pretty
  2786 printer); internal interface is provided by add_modesyntax(_i);
  2787 
  2788 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2789 be used in conjunction with the Isabelle symbol font; uses the
  2790 "symbols" syntax table;
  2791 
  2792 * added token_translation interface (may translate name tokens in
  2793 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2794 the current print_mode); IMPORTANT: user print translation functions
  2795 are responsible for marking newly introduced bounds
  2796 (Syntax.mark_boundT);
  2797 
  2798 * token translations for modes "xterm" and "xterm_color" that display
  2799 names in bold, underline etc. or colors (which requires a color
  2800 version of xterm);
  2801 
  2802 * infixes may now be declared with names independent of their syntax;
  2803 
  2804 * added typed_print_translation (like print_translation, but may
  2805 access type of constant);
  2806 
  2807 
  2808 *** Classical Reasoner ***
  2809 
  2810 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2811 some limitations.  Blast_tac...
  2812   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2813   + ignores elimination rules that don't have the correct format
  2814         (the conclusion MUST be a formula variable)
  2815   + ignores types, which can make HOL proofs fail
  2816   + rules must not require higher-order unification, e.g. apply_type in ZF
  2817     [message "Function Var's argument not a bound variable" relates to this]
  2818   + its proof strategy is more general but can actually be slower
  2819 
  2820 * substitution with equality assumptions no longer permutes other
  2821 assumptions;
  2822 
  2823 * minor changes in semantics of addafter (now called addaltern); renamed
  2824 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2825 (and access functions for it);
  2826 
  2827 * improved combination of classical reasoner and simplifier:
  2828   + functions for handling clasimpsets
  2829   + improvement of addss: now the simplifier is called _after_ the
  2830     safe steps.
  2831   + safe variant of addss called addSss: uses safe simplifications
  2832     _during_ the safe steps. It is more complete as it allows multiple
  2833     instantiations of unknowns (e.g. with slow_tac).
  2834 
  2835 *** Simplifier ***
  2836 
  2837 * added interface for simplification procedures (functions that
  2838 produce *proven* rewrite rules on the fly, depending on current
  2839 redex);
  2840 
  2841 * ordering on terms as parameter (used for ordered rewriting);
  2842 
  2843 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2844 
  2845 * the solver is now split into a safe and an unsafe part.
  2846 This should be invisible for the normal user, except that the
  2847 functions setsolver and addsolver have been renamed to setSolver and
  2848 addSolver; added safe_asm_full_simp_tac;
  2849 
  2850 
  2851 *** HOL ***
  2852 
  2853 * a generic induction tactic `induct_tac' which works for all datatypes and
  2854 also for type `nat';
  2855 
  2856 * a generic case distinction tactic `exhaust_tac' which works for all
  2857 datatypes and also for type `nat';
  2858 
  2859 * each datatype comes with a function `size';
  2860 
  2861 * patterns in case expressions allow tuple patterns as arguments to
  2862 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2863 
  2864 * primrec now also works with type nat;
  2865 
  2866 * recdef: a new declaration form, allows general recursive functions to be
  2867 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2868 
  2869 * the constant for negation has been renamed from "not" to "Not" to
  2870 harmonize with FOL, ZF, LK, etc.;
  2871 
  2872 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2873 infinite lists;
  2874 
  2875 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2876 
  2877 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2878 problems in commutative rings, using axiomatic type classes for + and *;
  2879 
  2880 * more examples in HOL/MiniML and HOL/Auth;
  2881 
  2882 * more default rewrite rules for quantifiers, union/intersection;
  2883 
  2884 * a new constant `arbitrary == @x.False';
  2885 
  2886 * HOLCF/IOA replaces old HOL/IOA;
  2887 
  2888 * HOLCF changes: derived all rules and arities
  2889   + axiomatic type classes instead of classes
  2890   + typedef instead of faking type definitions
  2891   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2892   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2893   + eliminated the types void, one, tr
  2894   + use unit lift and bool lift (with translations) instead of one and tr
  2895   + eliminated blift from Lift3.thy (use Def instead of blift)
  2896   all eliminated rules are derived as theorems --> no visible changes ;
  2897 
  2898 
  2899 *** ZF ***
  2900 
  2901 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2902 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2903 as ZF_cs addSIs [equalityI];
  2904 
  2905 
  2906 
  2907 New in Isabelle94-7 (November 96)
  2908 ---------------------------------
  2909 
  2910 * allowing negative levels (as offsets) in prlev and choplev;
  2911 
  2912 * super-linear speedup for large simplifications;
  2913 
  2914 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2915 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2916 FAIL); can suppress it using the command Delsimps (ex_simps @
  2917 all_simps); De Morgan laws are also now included, by default;
  2918 
  2919 * improved printing of ==>  :  ~:
  2920 
  2921 * new object-logic "Sequents" adds linear logic, while replacing LK
  2922 and Modal (thanks to Sara Kalvala);
  2923 
  2924 * HOL/Auth: correctness proofs for authentication protocols;
  2925 
  2926 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2927 examples on HOL/Auth);
  2928 
  2929 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2930 the rewriter and classical reasoner simultaneously;
  2931 
  2932 * function uresult no longer returns theorems in "standard" format;
  2933 regain previous version by: val uresult = standard o uresult;
  2934 
  2935 
  2936 
  2937 New in Isabelle94-6
  2938 -------------------
  2939 
  2940 * oracles -- these establish an interface between Isabelle and trusted
  2941 external reasoners, which may deliver results as theorems;
  2942 
  2943 * proof objects (in particular record all uses of oracles);
  2944 
  2945 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2946 
  2947 * "constdefs" section in theory files;
  2948 
  2949 * "primrec" section (HOL) no longer requires names;
  2950 
  2951 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2952 
  2953 
  2954 
  2955 New in Isabelle94-5
  2956 -------------------
  2957 
  2958 * reduced space requirements;
  2959 
  2960 * automatic HTML generation from theories;
  2961 
  2962 * theory files no longer require "..." (quotes) around most types;
  2963 
  2964 * new examples, including two proofs of the Church-Rosser theorem;
  2965 
  2966 * non-curried (1994) version of HOL is no longer distributed;
  2967 
  2968 
  2969 
  2970 New in Isabelle94-4
  2971 -------------------
  2972 
  2973 * greatly reduced space requirements;
  2974 
  2975 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2976 
  2977 * searchable theorem database (see the section "Retrieving theorems" on
  2978 page 8 of the Reference Manual);
  2979 
  2980 * new examples, including Grabczewski's monumental case study of the
  2981 Axiom of Choice;
  2982 
  2983 * The previous version of HOL renamed to Old_HOL;
  2984 
  2985 * The new version of HOL (previously called CHOL) uses a curried syntax
  2986 for functions.  Application looks like f a b instead of f(a,b);
  2987 
  2988 * Mutually recursive inductive definitions finally work in HOL;
  2989 
  2990 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2991 translates to the operator "split";
  2992 
  2993 
  2994 
  2995 New in Isabelle94-3
  2996 -------------------
  2997 
  2998 * new infix operator, addss, allowing the classical reasoner to
  2999 perform simplification at each step of its search.  Example:
  3000         fast_tac (cs addss ss)
  3001 
  3002 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3003 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3004 look like (a,b) instead of <a,b>;
  3005 
  3006 * PLEASE NOTE: CHOL will eventually replace HOL!
  3007 
  3008 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3009 It translates to the operator "split".  A new theory of integers is available;
  3010 
  3011 * In ZF, integer numerals now denote two's-complement binary integers.
  3012 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3013 
  3014 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3015 of the Axiom of Choice;
  3016 
  3017 
  3018 
  3019 New in Isabelle94-2
  3020 -------------------
  3021 
  3022 * Significantly faster resolution;
  3023 
  3024 * the different sections in a .thy file can now be mixed and repeated
  3025 freely;
  3026 
  3027 * Database of theorems for FOL, HOL and ZF.  New
  3028 commands including qed, qed_goal and bind_thm store theorems in the database.
  3029 
  3030 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3031 a given theory (thms_of), or find out what theory a theorem was proved in
  3032 (theory_of_thm);
  3033 
  3034 * Bugs fixed in the inductive definition and datatype packages;
  3035 
  3036 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3037 and HOL_dup_cs obsolete;
  3038 
  3039 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3040 have been removed;
  3041 
  3042 * Simpler definition of function space in ZF;
  3043 
  3044 * new results about cardinal and ordinal arithmetic in ZF;
  3045 
  3046 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3047 types;
  3048 
  3049 
  3050 $Id$