NEWS
author wenzelm
Thu Apr 21 22:02:06 2005 +0200 (2005-04-21)
changeset 15801 d2f5ca3c048d
parent 15778 98af3693f6b3
child 15852 4f1a78454452
permissions -rw-r--r--
superceded by Pure.thy and CPure.thy;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * ML: The type Library.option is no more, along with the exception
    10   Library.OPTION: Isabelle now uses the standard option type.  The
    11   functions the, is_some, is_none, etc. are still in Library, but
    12   the constructors are now SOME and NONE instead of Some and None.
    13   They raise the exception Option.
    14 
    15 * ML: The exception LIST is no more, the standard exceptions Empty and
    16   Subscript, as well as Library.UnequalLengths are used instead.  This
    17   means that function like Library.hd and Library.tl are gone, as the
    18   standard hd and tl functions suffice.
    19 
    20   A number of basic functions are now no longer exported to the top ML
    21   level, as they are variants of standard functions.  The following
    22   suggests how one can translate existing code:
    23 
    24     the x = valOf x
    25     if_none x y = getOpt(x,y)
    26     is_some x = isSome x
    27     apsome f x = Option.map f x
    28     rev_append xs ys = List.revAppend(xs,ys)
    29     nth_elem(i,xs) = List.nth(xs,i)
    30     last_elem xs = List.last xs
    31     flat xss = List.concat xss
    32     seq fs = app fs
    33     partition P xs = List.partition P xs
    34     filter P xs = List.filter P xs
    35     mapfilter f xs = List.mapPartial f xs
    36 
    37   The final four functions, take, drop, foldl, and foldr, are somewhat
    38   more complicated (especially the semantics of take and drop differ
    39   from the standard).
    40 
    41   A simple solution to broken code is to include "open Library" at the
    42   beginning of a structure.  Everything after that will be as before.
    43 
    44 * Theory headers: the new header syntax for Isar theories is
    45 
    46   theory <name>
    47   imports <theory1> ... <theoryn>
    48   begin
    49 
    50   optionally also with a "files" section. The syntax
    51 
    52   theory <name> = <theory1> + ... + <theoryn>:
    53 
    54   will still be supported for some time but will eventually disappear.
    55   The syntax of old-style theories has not changed.
    56 
    57 * Theory loader: parent theories can now also be referred to via
    58   relative and absolute paths.
    59 
    60 * Provers/quasi.ML:  new transitivity reasoners for transitivity only
    61   and quasi orders.
    62 
    63 * Provers/trancl.ML:  new transitivity reasoner for transitive and
    64   reflexive-transitive closure of relations.
    65 
    66 * Provers/blast.ML:  new reference depth_limit to make blast's depth
    67   limit (previously hard-coded with a value of 20) user-definable.
    68 
    69 * Provers: new version of the subst method, for single-step rewriting: it now
    70   works in bound variable contexts. New is subst (asm), for rewriting an
    71   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    72   subterm than the original subst method, which is still available under the
    73   name simplesubst.
    74 
    75 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    76   More generally, erule now works even if the major premise of the elimination rule
    77   contains !! or ==>.
    78 
    79 * Pure: considerably improved version of 'constdefs' command.  Now
    80   performs automatic type-inference of declared constants; additional
    81   support for local structure declarations (cf. locales and HOL
    82   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    83   to observe strictly sequential dependencies of definitions within a
    84   single 'constdefs' section; moreover, the declared name needs to be
    85   an identifier.  If all fails, consider to fall back on 'consts' and
    86   'defs' separately.
    87 
    88 * Pure: improved indexed syntax and implicit structures.  First of
    89   all, indexed syntax provides a notational device for subscripted
    90   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    91   expressions.  Secondly, in a local context with structure
    92   declarations, number indexes \<^sub>n or the empty index (default
    93   number 1) refer to a certain fixed variable implicitly; option
    94   show_structs controls printing of implicit structures.  Typical
    95   applications of these concepts involve record types and locales.
    96 
    97 * Pure: clear separation of logical types and nonterminals, where the
    98   latter may only occur in 'syntax' specifications or type
    99   abbreviations.  Before that distinction was only partially
   100   implemented via type class "logic" vs. "{}".  Potential
   101   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
   102   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
   103   specifications may require further adaption (e.g. Cube/Base.thy).
   104 
   105 * Pure: removed obsolete type class "logic", use the top sort {}
   106   instead.  Note that non-logical types should be declared as
   107   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
   108   object-logic specifications.
   109 
   110 * Pure: command 'no_syntax' removes grammar declarations (and
   111   translations) resulting from the given syntax specification, which
   112   is interpreted in the same manner as for the 'syntax' command.
   113 
   114 * Pure: print_tac now outputs the goal through the trace channel.
   115 
   116 * Pure: reference Namespace.unique_names included.  If true the
   117   (shortest) namespace-prefix is printed to disambiguate conflicts (as
   118   yet). If false the first entry wins (as during parsing). Default
   119   value is true.
   120 
   121 * Pure: tuned internal renaming of symbolic identifiers -- attach
   122   primes instead of base 26 numbers.
   123 
   124 * Pure: new flag show_var_qmarks to control printing of leading
   125   question marks of variable names.
   126 
   127 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   128 
   129 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   130   specified in mixfix annotations as "(00...)".
   131 
   132 * Pure/Syntax: 'advanced' translation functions (parse_translation
   133   etc.) may depend on the signature of the theory context being
   134   presently used for parsing/printing, see also isar-ref manual.
   135 
   136 * Pure/Simplifier: simplification procedures may now take the current
   137   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   138   interface), which is very useful for calling the Simplifier
   139   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   140   simprocs is gone -- use prems_of_ss on the simpset instead.
   141   Moreover, the low-level mk_simproc no longer applies Logic.varify
   142   internally, to allow for use in a context of fixed variables.
   143 
   144 * Pure/Simplifier: Command "find_rewrites" takes a string and lists all
   145   equality theorems (not just those declared as simp!) whose left-hand
   146   side matches the term given via the string. In PG the command can be
   147   activated via Isabelle -> Show me -> matching rewrites.
   148 
   149 * Isar debugging: new reference Toplevel.debug; default false.
   150   Set to make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   151   
   152 * Locales:
   153   - "includes" disallowed in declaration of named locales (command "locale").
   154   - Fixed parameter management in theorem generation for goals with "includes".
   155     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   156 
   157 * Locales:  new commands for the interpretation of locale expressions
   158   in theories (interpretation) and proof contexts (interpret).  These take an
   159   instantiation of the locale parameters and compute proof obligations from
   160   the instantiated specification.  After the obligations have been discharged,
   161   the instantiated theorems of the locale are added to the theory or proof
   162   context.  Interpretation is smart in that already active interpretations
   163   do not occur in proof obligations, neither are instantiated theorems stored
   164   in duplicate.
   165   Use print_interps to inspect active interpretations of a particular locale.
   166   For details, see the Isar Reference manual.
   167 
   168 * Locales: proper static binding of attribute syntax -- i.e. types /
   169   terms / facts mentioned as arguments are always those of the locale
   170   definition context, independently of the context of later
   171   invocations.  Moreover, locale operations (renaming and type / term
   172   instantiation) are applied to attribute arguments as expected.
   173 
   174   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   175   of actual attributes; rare situations may require Attrib.attribute
   176   to embed those attributes into Attrib.src that lack concrete syntax.
   177 
   178   Attribute implementations need to cooperate properly with the static
   179   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   180   Attrib.XXX_thm etc. already do the right thing without further
   181   intervention.  Only unusual applications -- such as "where" or "of"
   182   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   183   both on the context and the facts involved -- may have to assign
   184   parsed values to argument tokens explicitly.
   185 
   186 * Attributes 'induct' and 'cases': type or set names may now be
   187   locally fixed variables as well.
   188 
   189 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   190   selections of theorems in named facts via indices.
   191 
   192 * Pure: reorganized bootstrapping of the Pure theories; CPure is now
   193   derived from Pure, which contains all common declarations already.
   194   Both theories are defined via plain Isabelle/Isar .thy files.
   195   INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   196   CPure.elim / CPure.dest attributes) now appear in the Pure name
   197   space; use isatool fixcpure to adapt your theory and ML sources.
   198 
   199 
   200 *** Document preparation ***
   201 
   202 * New antiquotations @{lhs thm} and @{rhs thm} printing the lhs/rhs of
   203   definitions, equations, inequations etc.
   204 
   205 * Antiquotations now provide the option 'locale=NAME' to specify an
   206   alternative context used for evaluating and printing the subsequent
   207   argument, as in @{thm [locale=LC] fold_commute}, for example.
   208 
   209 * Commands 'display_drafts' and 'print_drafts' perform simple output
   210   of raw sources.  Only those symbols that do not require additional
   211   LaTeX packages (depending on comments in isabellesym.sty) are
   212   displayed properly, everything else is left verbatim.  We use
   213   isatool display and isatool print as front ends; these are subject
   214   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   215 
   216 * Proof scripts as well as some other commands such as ML or
   217   parse/print_translation can now be hidden in the document.  Hiding
   218   is enabled by default, and can be disabled either via the option '-H
   219   false' of isatool usedir or by resetting the reference variable
   220   IsarOutput.hide_commands. Additional commands to be hidden may be
   221   declared using IsarOutput.add_hidden_commands.
   222 
   223 
   224 *** HOL ***
   225 
   226 * Datatype induction via method `induct' now preserves the name of the
   227   induction variable. For example, when proving P(xs::'a list) by induction
   228   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   229   P(list) ==> P(a#list) as previously.
   230 
   231 * HOL/record: reimplementation of records. Improved scalability for
   232   records with many fields, avoiding performance problems for type
   233   inference. Records are no longer composed of nested field types, but
   234   of nested extension types. Therefore the record type only grows
   235   linear in the number of extensions and not in the number of fields.
   236   The top-level (users) view on records is preserved.  Potential
   237   INCOMPATIBILITY only in strange cases, where the theory depends on
   238   the old record representation. The type generated for a record is
   239   called <record_name>_ext_type.
   240 
   241 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   242   enabled to skip the proofs triggered by a record definition or a
   243   simproc (if quick_and_dirty is enabled). Definitions of large
   244   records can take quite long.
   245 
   246 * HOL/record: "record_upd_simproc" for simplification of multiple
   247   record updates enabled by default.  Moreover, trivial updates are
   248   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   249   occasionally, since simplification is more powerful by default.
   250 
   251 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   252 
   253   syntax (epsilon)
   254     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   255 
   256   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   257   and x-symbol; use option '-m epsilon' to get it actually printed.
   258   Moreover, the mathematically important symbolic identifier
   259   \<epsilon> becomes available as variable, constant etc.
   260 
   261 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   262   Similarly for all quantifiers: "ALL x > y" etc.
   263   The x-symbol for >= is \<ge>.
   264 
   265 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}"
   266            (and similarly for "\<in>" instead of ":")
   267 
   268 * HOL/SetInterval: The syntax for open intervals has changed:
   269 
   270   Old         New
   271   {..n(}   -> {..<n}
   272   {)n..}   -> {n<..}
   273   {m..n(}  -> {m..<n}
   274   {)m..n}  -> {m<..n}
   275   {)m..n(} -> {m<..<n}
   276 
   277   The old syntax is still supported but will disappear in the future.
   278   For conversion use the following emacs search and replace patterns:
   279 
   280   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   281   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   282 
   283   They are not perfect but work quite well.
   284 
   285 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   286 
   287   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   288   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   289 
   290   There is new syntax for summation over finite sets:
   291 
   292   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   293   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   294   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   295   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   296 
   297   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   298   now translates into 'setsum' as above.
   299 
   300 * HOL: Finite set induction: In Isar proofs, the insert case is now
   301   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   302 
   303 * HOL/Simplifier:
   304 
   305   - Is now set up to reason about transitivity chains involving "trancl"
   306   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   307   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   308   occasionally as simplification may now solve more goals than previously.
   309 
   310   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   311   all partial orders (class "order"), in particular numbers and sets. For
   312   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   313 
   314   - Simproc for "let x = a in f x"
   315   If a is a free or bound variable or a constant then the let is unfolded.
   316   Otherwise first a is simplified to a', and then f a' is simplified to
   317   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   318   otherwise we unfold the let and arrive at g. The simproc can be 
   319   enabled/disabled by the reference use_let_simproc. Potential
   320   INCOMPATIBILITY since simplification is more powerful by default.
   321 
   322 * HOL: The 'refute' command has been extended to support a much larger
   323   fragment of HOL, including axiomatic type classes, constdefs and typedefs,
   324   inductive datatypes and recursion.
   325 
   326 
   327 *** HOLCF ***
   328 
   329 * HOLCF: discontinued special version of 'constdefs' (which used to
   330   support continuous functions) in favor of the general Pure one with
   331   full type-inference.
   332 
   333 
   334 *** ZF ***
   335 
   336 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   337   First Isomorphism Theorem (on quotienting by the kernel of a
   338   homomorphism).
   339 
   340 * ZF/Simplifier: install second copy of type solver that actually
   341   makes use of TC rules declared to Isar proof contexts (or locales);
   342   the old version is still required for ML proof scripts.
   343 
   344 
   345 *** System ***
   346 
   347 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   348   (containing Boolean satisfiability problems) into Isabelle/HOL
   349   theories.
   350 
   351 * isatool usedir: option -f allows specification of the ML file to be
   352   used by Isabelle; default is ROOT.ML.
   353 
   354 * symlinks to Isabelle, isabelle, isabelle-interface and isabelle-process
   355   are allowed; isabelle directories are determined based on link target.
   356 
   357 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   358   isatool doc, isatool mkdir, display_drafts etc.).
   359 
   360 
   361 *** ML ***
   362 
   363 * Pure: output via the Isabelle channels of writeln/warning/error
   364   etc. is now passed through Output.output, with a hook for arbitrary
   365   transformations depending on the print_mode (cf. Output.add_mode --
   366   the first active mode that provides a output function wins).
   367   Already formatted output may be embedded into further text via
   368   Output.raw; the result of Pretty.string_of/str_of and derived
   369   functions (string_of_term/cterm/thm etc.) is already marked raw to
   370   accommodate easy composition of diagnostic messages etc.
   371   Programmers rarely need to care about Output.output or Output.raw at
   372   all, with some notable exceptions: Output.output is required when
   373   bypassing the standard channels (writeln etc.), or in token
   374   translations to produce properly formatted results; Output.raw is
   375   required when capturing already output material that will eventually
   376   be presented to the user a second time.  For the default print mode,
   377   both Output.output and Output.raw have no effect.
   378 
   379 * Provers: Simplifier and Classical Reasoner now support proof context
   380   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   381   components are stored in the theory and patched into the
   382   simpset/claset when used in an Isar proof context.  Context
   383   dependent components are maintained by the following theory
   384   operations:
   385 
   386     Simplifier.add_context_simprocs
   387     Simplifier.del_context_simprocs
   388     Simplifier.set_context_subgoaler
   389     Simplifier.reset_context_subgoaler
   390     Simplifier.add_context_looper
   391     Simplifier.del_context_looper
   392     Simplifier.add_context_unsafe_solver
   393     Simplifier.add_context_safe_solver
   394 
   395     Classical.add_context_safe_wrapper
   396     Classical.del_context_safe_wrapper
   397     Classical.add_context_unsafe_wrapper
   398     Classical.del_context_unsafe_wrapper
   399 
   400   IMPORTANT NOTE: proof tools (methods etc.) need to use
   401   local_simpset_of and local_claset_of to instead of the primitive
   402   Simplifier.get_local_simpset and Classical.get_local_claset,
   403   respectively, in order to see the context dependent fields!
   404 
   405 
   406 
   407 New in Isabelle2004 (April 2004)
   408 --------------------------------
   409 
   410 *** General ***
   411 
   412 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   413   Replaces linorder.ML.
   414 
   415 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   416   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   417   (\<a>...\<z>), are now considered normal letters, and can therefore
   418   be used anywhere where an ASCII letter (a...zA...Z) has until
   419   now. COMPATIBILITY: This obviously changes the parsing of some
   420   terms, especially where a symbol has been used as a binder, say
   421   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   422   as an identifier.  Fix it by inserting a space around former
   423   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   424   existing theory and ML files.
   425 
   426 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   427 
   428 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   429   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   430   a normal (but invisible) letter. For multiple letter subscripts repeat
   431   \<^isub> like this: x\<^isub>1\<^isub>2.
   432 
   433 * Pure: There are now sub-/superscripts that can span more than one
   434   character. Text between \<^bsub> and \<^esub> is set in subscript in
   435   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   436   superscript. The new control characters are not identifier parts.
   437 
   438 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   439   content of "..." to the latex file instead of \isacntrl... . The "..."
   440   may consist of any printable characters excluding the end bracket >.
   441 
   442 * Pure: Using new Isar command "finalconsts" (or the ML functions
   443   Theory.add_finals or Theory.add_finals_i) it is now possible to
   444   declare constants "final", which prevents their being given a definition
   445   later.  It is useful for constants whose behaviour is fixed axiomatically
   446   rather than definitionally, such as the meta-logic connectives.
   447 
   448 * Pure: 'instance' now handles general arities with general sorts
   449   (i.e. intersections of classes),
   450 
   451 * Presentation: generated HTML now uses a CSS style sheet to make layout
   452   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   453   It can be changed to alter the colors/layout of generated pages.
   454 
   455 
   456 *** Isar ***
   457 
   458 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   459   cut_tac, subgoal_tac and thin_tac:
   460   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   461     locales are no longer forced to write Isar proof scripts.
   462     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   463     emulations.
   464   - INCOMPATIBILITY: names of variables to be instantiated may no
   465     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   466     This is consistent with the instantiation attribute "where".
   467 
   468 * Attributes "where" and "of":
   469   - Now take type variables of instantiated theorem into account when reading
   470     the instantiation string.  This fixes a bug that caused instantiated
   471     theorems to have too special types in some circumstances.
   472   - "where" permits explicit instantiations of type variables.
   473 
   474 * Calculation commands "moreover" and "also" no longer interfere with
   475   current facts ("this"), admitting arbitrary combinations with "then"
   476   and derived forms.
   477 
   478 * Locales:
   479   - Goal statements involving the context element "includes" no longer
   480     generate theorems with internal delta predicates (those ending on
   481     "_axioms") in the premise.
   482     Resolve particular premise with <locale>.intro to obtain old form.
   483   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   484     specification and "includes" elements in goal statement.
   485   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   486     [intro?] and [elim?] (respectively) by default.
   487   - Experimental command for instantiation of locales in proof contexts:
   488         instantiate <label>[<attrs>]: <loc>
   489     Instantiates locale <loc> and adds all its theorems to the current context
   490     taking into account their attributes.  Label and attrs are optional
   491     modifiers, like in theorem declarations.  If present, names of
   492     instantiated theorems are qualified with <label>, and the attributes
   493     <attrs> are applied after any attributes these theorems might have already.
   494       If the locale has assumptions, a chained fact of the form
   495     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   496     are derived.  The command does not support old-style locales declared
   497     with "locale (open)".
   498       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   499 
   500 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   501   (Isar) contexts.
   502 
   503 
   504 *** HOL ***
   505 
   506 * Proof import: new image HOL4 contains the imported library from
   507   the HOL4 system with about 2500 theorems. It is imported by
   508   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   509   can be used like any other Isabelle image.  See
   510   HOL/Import/HOL/README for more information.
   511 
   512 * Simplifier:
   513   - Much improved handling of linear and partial orders.
   514     Reasoners for linear and partial orders are set up for type classes
   515     "linorder" and "order" respectively, and are added to the default simpset
   516     as solvers.  This means that the simplifier can build transitivity chains
   517     to solve goals from the assumptions.
   518   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   519     of blast or auto after simplification become unnecessary because the goal
   520     is solved by simplification already.
   521 
   522 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   523     all proved in axiomatic type classes for semirings, rings and fields.
   524 
   525 * Numerics:
   526   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   527     now formalized using the Ring_and_Field theory mentioned above.
   528   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   529     than before, because now they are set up once in a generic manner.
   530   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   531     Look for the general versions in Ring_and_Field (and Power if they concern
   532     exponentiation).
   533 
   534 * Type "rat" of the rational numbers is now available in HOL-Complex.
   535 
   536 * Records:
   537   - Record types are now by default printed with their type abbreviation
   538     instead of the list of all field types. This can be configured via
   539     the reference "print_record_type_abbr".
   540   - Simproc "record_upd_simproc" for simplification of multiple updates added
   541     (not enabled by default).
   542   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   543     EX x. x = sel r to True (not enabled by default).
   544   - Tactic "record_split_simp_tac" to split and simplify records added.
   545 
   546 * 'specification' command added, allowing for definition by
   547   specification.  There is also an 'ax_specification' command that
   548   introduces the new constants axiomatically.
   549 
   550 * arith(_tac) is now able to generate counterexamples for reals as well.
   551 
   552 * HOL-Algebra: new locale "ring" for non-commutative rings.
   553 
   554 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   555   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   556 
   557 * HOL-Matrix: a first theory for matrices in HOL with an application of
   558   matrix theory to linear programming.
   559 
   560 * Unions and Intersections:
   561   The latex output syntax of UN and INT has been changed
   562   from "\Union x \in A. B" to "\Union_{x \in A} B"
   563   i.e. the index formulae has become a subscript.
   564   Similarly for "\Union x. B", and for \Inter instead of \Union.
   565 
   566 * Unions and Intersections over Intervals:
   567   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   568   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   569   like in normal math, and corresponding versions for < and for intersection.
   570 
   571 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   572   lexicographic dictonary ordering has been added as "lexord".
   573 
   574 * ML: the legacy theory structures Int and List have been removed. They had
   575   conflicted with ML Basis Library structures having the same names.
   576 
   577 * 'refute' command added to search for (finite) countermodels.  Only works
   578   for a fragment of HOL.  The installation of an external SAT solver is
   579   highly recommended.  See "HOL/Refute.thy" for details.
   580 
   581 * 'quickcheck' command: Allows to find counterexamples by evaluating
   582   formulae under an assignment of free variables to random values.
   583   In contrast to 'refute', it can deal with inductive datatypes,
   584   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   585   for examples.
   586 
   587 
   588 *** HOLCF ***
   589 
   590 * Streams now come with concatenation and are part of the HOLCF image
   591 
   592 
   593 
   594 New in Isabelle2003 (May 2003)
   595 ------------------------------
   596 
   597 *** General ***
   598 
   599 * Provers/simplifier:
   600 
   601   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   602     Assumptions are now subject to complete mutual simplification,
   603     not just from left to right. The simplifier now preserves
   604     the order of assumptions.
   605 
   606     Potential INCOMPATIBILITY:
   607 
   608     -- simp sometimes diverges where the old version did
   609        not, e.g. invoking simp on the goal
   610 
   611         [| P (f x); y = x; f x = f y |] ==> Q
   612 
   613        now gives rise to the infinite reduction sequence
   614 
   615         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   616 
   617        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   618        kind of problem.
   619 
   620     -- Tactics combining classical reasoner and simplification (such as auto)
   621        are also affected by this change, because many of them rely on
   622        simp. They may sometimes diverge as well or yield a different numbers
   623        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   624        in case of problems. Sometimes subsequent calls to the classical
   625        reasoner will fail because a preceeding call to the simplifier too
   626        eagerly simplified the goal, e.g. deleted redundant premises.
   627 
   628   - The simplifier trace now shows the names of the applied rewrite rules
   629 
   630   - You can limit the number of recursive invocations of the simplifier
   631     during conditional rewriting (where the simplifie tries to solve the
   632     conditions before applying the rewrite rule):
   633     ML "simp_depth_limit := n"
   634     where n is an integer. Thus you can force termination where previously
   635     the simplifier would diverge.
   636 
   637   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   638 
   639   - No longer aborts on failed congruence proof.  Instead, the
   640     congruence is ignored.
   641 
   642 * Pure: New generic framework for extracting programs from constructive
   643   proofs. See HOL/Extraction.thy for an example instantiation, as well
   644   as HOL/Extraction for some case studies.
   645 
   646 * Pure: The main goal of the proof state is no longer shown by default, only
   647 the subgoals. This behaviour is controlled by a new flag.
   648    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   649 (ML: Proof.show_main_goal).
   650 
   651 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   652 rules whose conclusion matches subgoal 1:
   653       PG menu: Isabelle/Isar -> Show me -> matching rules
   654 The rules are ordered by how closely they match the subgoal.
   655 In particular, rules that solve a subgoal outright are displayed first
   656 (or rather last, the way they are printed).
   657 (ML: ProofGeneral.print_intros())
   658 
   659 * Pure: New flag trace_unify_fail causes unification to print
   660 diagnostic information (PG: in trace buffer) when it fails. This is
   661 useful for figuring out why single step proofs like rule, erule or
   662 assumption failed.
   663 
   664 * Pure: Locale specifications now produce predicate definitions
   665 according to the body of text (covering assumptions modulo local
   666 definitions); predicate "loc_axioms" covers newly introduced text,
   667 while "loc" is cumulative wrt. all included locale expressions; the
   668 latter view is presented only on export into the global theory
   669 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   670 on the old view without predicates;
   671 
   672 * Pure: predefined locales "var" and "struct" are useful for sharing
   673 parameters (as in CASL, for example); just specify something like
   674 ``var x + var y + struct M'' as import;
   675 
   676 * Pure: improved thms_containing: proper indexing of facts instead of
   677 raw theorems; check validity of results wrt. current name space;
   678 include local facts of proof configuration (also covers active
   679 locales), cover fixed variables in index; may use "_" in term
   680 specification; an optional limit for the number of printed facts may
   681 be given (the default is 40);
   682 
   683 * Pure: disallow duplicate fact bindings within new-style theory files
   684 (batch-mode only);
   685 
   686 * Provers: improved induct method: assumptions introduced by case
   687 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   688 the goal statement); "foo" still refers to all facts collectively;
   689 
   690 * Provers: the function blast.overloaded has been removed: all constants
   691 are regarded as potentially overloaded, which improves robustness in exchange
   692 for slight decrease in efficiency;
   693 
   694 * Provers/linorder: New generic prover for transitivity reasoning over
   695 linear orders.  Note: this prover is not efficient!
   696 
   697 * Isar: preview of problems to finish 'show' now produce an error
   698 rather than just a warning (in interactive mode);
   699 
   700 
   701 *** HOL ***
   702 
   703 * arith(_tac)
   704 
   705  - Produces a counter example if it cannot prove a goal.
   706    Note that the counter example may be spurious if the goal is not a formula
   707    of quantifier-free linear arithmetic.
   708    In ProofGeneral the counter example appears in the trace buffer.
   709 
   710  - Knows about div k and mod k where k is a numeral of type nat or int.
   711 
   712  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   713    linear arithmetic fails. This takes account of quantifiers and divisibility.
   714    Presburger arithmetic can also be called explicitly via presburger(_tac).
   715 
   716 * simp's arithmetic capabilities have been enhanced a bit: it now
   717 takes ~= in premises into account (by performing a case split);
   718 
   719 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   720 are distributed over a sum of terms;
   721 
   722 * New tactic "trans_tac" and method "trans" instantiate
   723 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   724 "<=", "<" and "=").
   725 
   726 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   727 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   728 
   729 * 'typedef' command has new option "open" to suppress the set
   730 definition;
   731 
   732 * functions Min and Max on finite sets have been introduced (theory
   733 Finite_Set);
   734 
   735 * attribute [symmetric] now works for relations as well; it turns
   736 (x,y) : R^-1 into (y,x) : R, and vice versa;
   737 
   738 * induct over a !!-quantified statement (say !!x1..xn):
   739   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   740 
   741 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   742 %x. None. Warning: empty_def now refers to the previously hidden definition
   743 of the empty set.
   744 
   745 * Algebra: formalization of classical algebra.  Intended as base for
   746 any algebraic development in Isabelle.  Currently covers group theory
   747 (up to Sylow's theorem) and ring theory (Universal Property of
   748 Univariate Polynomials).  Contributions welcome;
   749 
   750 * GroupTheory: deleted, since its material has been moved to Algebra;
   751 
   752 * Complex: new directory of the complex numbers with numeric constants,
   753 nonstandard complex numbers, and some complex analysis, standard and
   754 nonstandard (Jacques Fleuriot);
   755 
   756 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   757 
   758 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   759 Fleuriot);
   760 
   761 * Real/HahnBanach: updated and adapted to locales;
   762 
   763 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   764 Gray and Kramer);
   765 
   766 * UNITY: added the Meier-Sanders theory of progress sets;
   767 
   768 * MicroJava: bytecode verifier and lightweight bytecode verifier
   769 as abstract algorithms, instantiated to the JVM;
   770 
   771 * Bali: Java source language formalization. Type system, operational
   772 semantics, axiomatic semantics. Supported language features:
   773 classes, interfaces, objects,virtual methods, static methods,
   774 static/instance fields, arrays, access modifiers, definite
   775 assignment, exceptions.
   776 
   777 
   778 *** ZF ***
   779 
   780 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   781 universe, etc.);
   782 
   783 * Main ZF: virtually all theories converted to new-style format;
   784 
   785 
   786 *** ML ***
   787 
   788 * Pure: Tactic.prove provides sane interface for internal proofs;
   789 omits the infamous "standard" operation, so this is more appropriate
   790 than prove_goalw_cterm in many situations (e.g. in simprocs);
   791 
   792 * Pure: improved error reporting of simprocs;
   793 
   794 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   795 up simprocs;
   796 
   797 
   798 *** Document preparation ***
   799 
   800 * uses \par instead of \\ for line breaks in theory text. This may
   801 shift some page breaks in large documents. To get the old behaviour
   802 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   803 
   804 * minimized dependencies of isabelle.sty and isabellesym.sty on
   805 other packages
   806 
   807 * \<euro> now needs package babel/greek instead of marvosym (which
   808 broke \Rightarrow)
   809 
   810 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   811 textcomp package)
   812 
   813 
   814 
   815 New in Isabelle2002 (March 2002)
   816 --------------------------------
   817 
   818 *** Document preparation ***
   819 
   820 * greatly simplified document preparation setup, including more
   821 graceful interpretation of isatool usedir -i/-d/-D options, and more
   822 instructive isatool mkdir; users should basically be able to get
   823 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   824 users may run a separate document processing stage manually like this:
   825 "isatool usedir -D output HOL Test && isatool document Test/output";
   826 
   827 * theory dependency graph may now be incorporated into documents;
   828 isatool usedir -g true will produce session_graph.eps/.pdf for use
   829 with \includegraphics of LaTeX;
   830 
   831 * proper spacing of consecutive markup elements, especially text
   832 blocks after section headings;
   833 
   834 * support bold style (for single symbols only), input syntax is like
   835 this: "\<^bold>\<alpha>" or "\<^bold>A";
   836 
   837 * \<bullet> is now output as bold \cdot by default, which looks much
   838 better in printed text;
   839 
   840 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   841 note that these symbols are currently unavailable in Proof General /
   842 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   843 
   844 * isatool latex no longer depends on changed TEXINPUTS, instead
   845 isatool document copies the Isabelle style files to the target
   846 location;
   847 
   848 
   849 *** Isar ***
   850 
   851 * Pure/Provers: improved proof by cases and induction;
   852   - 'case' command admits impromptu naming of parameters (such as
   853     "case (Suc n)");
   854   - 'induct' method divinates rule instantiation from the inductive
   855     claim; no longer requires excessive ?P bindings for proper
   856     instantiation of cases;
   857   - 'induct' method properly enumerates all possibilities of set/type
   858     rules; as a consequence facts may be also passed through *type*
   859     rules without further ado;
   860   - 'induct' method now derives symbolic cases from the *rulified*
   861     rule (before it used to rulify cases stemming from the internal
   862     atomized version); this means that the context of a non-atomic
   863     statement becomes is included in the hypothesis, avoiding the
   864     slightly cumbersome show "PROP ?case" form;
   865   - 'induct' may now use elim-style induction rules without chaining
   866     facts, using ``missing'' premises from the goal state; this allows
   867     rules stemming from inductive sets to be applied in unstructured
   868     scripts, while still benefitting from proper handling of non-atomic
   869     statements; NB: major inductive premises need to be put first, all
   870     the rest of the goal is passed through the induction;
   871   - 'induct' proper support for mutual induction involving non-atomic
   872     rule statements (uses the new concept of simultaneous goals, see
   873     below);
   874   - append all possible rule selections, but only use the first
   875     success (no backtracking);
   876   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   877   - undeclared rule case names default to numbers 1, 2, 3, ...;
   878   - added 'print_induct_rules' (covered by help item in recent Proof
   879     General versions);
   880   - moved induct/cases attributes to Pure, methods to Provers;
   881   - generic method setup instantiated for FOL and HOL;
   882 
   883 * Pure: support multiple simultaneous goal statements, for example
   884 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   885 meta-level mechanism, this acts as if several individual goals had
   886 been stated separately; in particular common proof methods need to be
   887 repeated in order to cover all claims; note that a single elimination
   888 step is *not* sufficient to establish the two conjunctions, so this
   889 fails:
   890 
   891   assume "A & B" then have A and B ..   (*".." fails*)
   892 
   893 better use "obtain" in situations as above; alternative refer to
   894 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   895 
   896 * Pure: proper integration with ``locales''; unlike the original
   897 version by Florian Kammller, Isar locales package high-level proof
   898 contexts rather than raw logical ones (e.g. we admit to include
   899 attributes everywhere); operations on locales include merge and
   900 rename; support for implicit arguments (``structures''); simultaneous
   901 type-inference over imports and text; see also HOL/ex/Locales.thy for
   902 some examples;
   903 
   904 * Pure: the following commands have been ``localized'', supporting a
   905 target locale specification "(in name)": 'lemma', 'theorem',
   906 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   907 stored both within the locale and at the theory level (exported and
   908 qualified by the locale name);
   909 
   910 * Pure: theory goals may now be specified in ``long'' form, with
   911 ad-hoc contexts consisting of arbitrary locale elements. for example
   912 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   913 definitions may be given, too); the result is a meta-level rule with
   914 the context elements being discharged in the obvious way;
   915 
   916 * Pure: new proof command 'using' allows to augment currently used
   917 facts after a goal statement ('using' is syntactically analogous to
   918 'apply', but acts on the goal's facts only); this allows chained facts
   919 to be separated into parts given before and after a claim, as in
   920 ``from a and b have C using d and e <proof>'';
   921 
   922 * Pure: renamed "antecedent" case to "rule_context";
   923 
   924 * Pure: new 'judgment' command records explicit information about the
   925 object-logic embedding (used by several tools internally); no longer
   926 use hard-wired "Trueprop";
   927 
   928 * Pure: added 'corollary' command;
   929 
   930 * Pure: fixed 'token_translation' command;
   931 
   932 * Pure: removed obsolete 'exported' attribute;
   933 
   934 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   935 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   936 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   937 
   938 * Pure: method 'atomize' presents local goal premises as object-level
   939 statements (atomic meta-level propositions); setup controlled via
   940 rewrite rules declarations of 'atomize' attribute; example
   941 application: 'induct' method with proper rule statements in improper
   942 proof *scripts*;
   943 
   944 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   945 now consider the syntactic context of assumptions, giving a better
   946 chance to get type-inference of the arguments right (this is
   947 especially important for locales);
   948 
   949 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   950 mode;
   951 
   952 * Pure/obtain: the formal conclusion "thesis", being marked as
   953 ``internal'', may no longer be reference directly in the text;
   954 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   955 situations;
   956 
   957 * Pure: generic 'sym' attribute which declares a rule both as pure
   958 'elim?' and for the 'symmetric' operation;
   959 
   960 * Pure: marginal comments ``--'' may now occur just anywhere in the
   961 text; the fixed correlation with particular command syntax has been
   962 discontinued;
   963 
   964 * Pure: new method 'rules' is particularly well-suited for proof
   965 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
   966 but often produces more compact proof terms with less detours;
   967 
   968 * Pure/Provers/classical: simplified integration with pure rule
   969 attributes and methods; the classical "intro?/elim?/dest?"
   970 declarations coincide with the pure ones; the "rule" method no longer
   971 includes classically swapped intros; "intro" and "elim" methods no
   972 longer pick rules from the context; also got rid of ML declarations
   973 AddXIs/AddXEs/AddXDs; all of this has some potential for
   974 INCOMPATIBILITY;
   975 
   976 * Provers/classical: attribute 'swapped' produces classical inversions
   977 of introduction rules;
   978 
   979 * Provers/simplifier: 'simplified' attribute may refer to explicit
   980 rules instead of full simplifier context; 'iff' attribute handles
   981 conditional rules;
   982 
   983 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
   984 
   985 * HOL: 'recdef' now fails on unfinished automated proofs, use
   986 "(permissive)" option to recover old behavior;
   987 
   988 * HOL: 'inductive' no longer features separate (collective) attributes
   989 for 'intros' (was found too confusing);
   990 
   991 * HOL: properly declared induction rules less_induct and
   992 wf_induct_rule;
   993 
   994 
   995 *** HOL ***
   996 
   997 * HOL: moved over to sane numeral syntax; the new policy is as
   998 follows:
   999 
  1000   - 0 and 1 are polymorphic constants, which are defined on any
  1001   numeric type (nat, int, real etc.);
  1002 
  1003   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1004   binary representation internally;
  1005 
  1006   - type nat has special constructor Suc, and generally prefers Suc 0
  1007   over 1::nat and Suc (Suc 0) over 2::nat;
  1008 
  1009 This change may cause significant problems of INCOMPATIBILITY; here
  1010 are some hints on converting existing sources:
  1011 
  1012   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1013   entities, so expressions involving "-" (unary or binary minus) need
  1014   to be spaced properly;
  1015 
  1016   - existing occurrences of "1" may need to be constraint "1::nat" or
  1017   even replaced by Suc 0; similar for old "2";
  1018 
  1019   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1020 
  1021   - remove all special provisions on numerals in proofs;
  1022 
  1023 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1024 representation (depends on bin_arith_simps in the default context);
  1025 
  1026 * HOL: symbolic syntax for x^2 (numeral 2);
  1027 
  1028 * HOL: the class of all HOL types is now called "type" rather than
  1029 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1030 in axclass/classes, instance/arities, and (usually rare) occurrences
  1031 in typings (of consts etc.); internally the class is called
  1032 "HOL.type", ML programs should refer to HOLogic.typeS;
  1033 
  1034 * HOL/record package improvements:
  1035   - new derived operations "fields" to build a partial record section,
  1036     "extend" to promote a fixed record to a record scheme, and
  1037     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1038     declared as simp by default;
  1039   - shared operations ("more", "fields", etc.) now need to be always
  1040     qualified) --- potential INCOMPATIBILITY;
  1041   - removed "make_scheme" operations (use "make" with "extend") --
  1042     INCOMPATIBILITY;
  1043   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1044   - provides cases/induct rules for use with corresponding Isar
  1045     methods (for concrete records, record schemes, concrete more
  1046     parts, and schematic more parts -- in that order);
  1047   - internal definitions directly based on a light-weight abstract
  1048     theory of product types over typedef rather than datatype;
  1049 
  1050 * HOL: generic code generator for generating executable ML code from
  1051 specifications; specific support for HOL constructs such as inductive
  1052 datatypes and sets, as well as recursive functions; can be invoked
  1053 via 'generate_code' theory section;
  1054 
  1055 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1056 
  1057 * HOL: consolidated and renamed several theories.  In particular:
  1058         Ord.thy has been absorbed into HOL.thy
  1059         String.thy has been absorbed into List.thy
  1060 
  1061 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1062 (beware of argument permutation!);
  1063 
  1064 * HOL: linorder_less_split superseded by linorder_cases;
  1065 
  1066 * HOL/List: "nodups" renamed to "distinct";
  1067 
  1068 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1069 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1070   - Ex_def has changed, now need to use some_eq_ex
  1071 
  1072 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1073 in this (rare) case use:
  1074 
  1075   delSWrapper "split_all_tac"
  1076   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1077 
  1078 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1079 MAY FAIL;
  1080 
  1081 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1082 Isabelle's type classes, ^ on functions and relations has too general
  1083 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1084 necessary to attach explicit type constraints;
  1085 
  1086 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1087 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1088 renamed accordingly (eg "compI" -> "rel_compI").
  1089 
  1090 * HOL: syntax translations now work properly with numerals and records
  1091 expressions;
  1092 
  1093 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1094 of "lam" -- INCOMPATIBILITY;
  1095 
  1096 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1097 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1098 renamed "Product_Type.unit";
  1099 
  1100 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1101 
  1102 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1103 the "cases" method);
  1104 
  1105 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1106 Florian Kammller);
  1107 
  1108 * HOL/IMP: updated and converted to new-style theory format; several
  1109 parts turned into readable document, with proper Isar proof texts and
  1110 some explanations (by Gerwin Klein);
  1111 
  1112 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1113 
  1114 * HOL-Hyperreal is now a logic image;
  1115 
  1116 
  1117 *** HOLCF ***
  1118 
  1119 * Isar: consts/constdefs supports mixfix syntax for continuous
  1120 operations;
  1121 
  1122 * Isar: domain package adapted to new-style theory format, e.g. see
  1123 HOLCF/ex/Dnat.thy;
  1124 
  1125 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1126 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1127 lift.induct_tac, always use UU instead of Undef;
  1128 
  1129 * HOLCF/IMP: updated and converted to new-style theory;
  1130 
  1131 
  1132 *** ZF ***
  1133 
  1134 * Isar: proper integration of logic-specific tools and packages,
  1135 including theory commands '(co)inductive', '(co)datatype',
  1136 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1137 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1138 
  1139 * theory Main no longer includes AC; for the Axiom of Choice, base
  1140 your theory on Main_ZFC;
  1141 
  1142 * the integer library now covers quotients and remainders, with many
  1143 laws relating division to addition, multiplication, etc.;
  1144 
  1145 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1146 typeless version of the formalism;
  1147 
  1148 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1149 format;
  1150 
  1151 * ZF/Induct: new directory for examples of inductive definitions,
  1152 including theory Multiset for multiset orderings; converted to
  1153 new-style theory format;
  1154 
  1155 * ZF: many new theorems about lists, ordinals, etc.;
  1156 
  1157 
  1158 *** General ***
  1159 
  1160 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1161 variable proof controls level of detail: 0 = no proofs (only oracle
  1162 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1163 also ref manual for further ML interfaces;
  1164 
  1165 * Pure/axclass: removed obsolete ML interface
  1166 goal_subclass/goal_arity;
  1167 
  1168 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1169 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1170 separate tokens, so expressions involving minus need to be spaced
  1171 properly;
  1172 
  1173 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1174 rather than "infixl" or "infixr";
  1175 
  1176 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1177 sort constraint specifications in type inference; e.g. "x::_::foo"
  1178 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1179 type variable);
  1180 
  1181 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1182 control output of nested => (types); the default behavior is
  1183 "type_brackets";
  1184 
  1185 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1186 tokens into AST constants;
  1187 
  1188 * Pure/syntax: prefer later declarations of translations and print
  1189 translation functions; potential INCOMPATIBILITY: need to reverse
  1190 multiple declarations for same syntax element constant;
  1191 
  1192 * Pure/show_hyps reset by default (in accordance to existing Isar
  1193 practice);
  1194 
  1195 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1196 addSafter;
  1197 
  1198 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1199 as well;
  1200 
  1201 * system: tested support for MacOS X; should be able to get Isabelle +
  1202 Proof General to work in a plain Terminal after installing Poly/ML
  1203 (e.g. from the Isabelle distribution area) and GNU bash alone
  1204 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1205 support requires further installations, e.g. from
  1206 http://fink.sourceforge.net/);
  1207 
  1208 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1209 
  1210 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1211 of 40 MB), cf. ML_OPTIONS;
  1212 
  1213 * system: Proof General keywords specification is now part of the
  1214 Isabelle distribution (see etc/isar-keywords.el);
  1215 
  1216 * system: support for persistent Proof General sessions (refrain from
  1217 outdating all loaded theories on startup); user may create writable
  1218 logic images like this: ``isabelle -q HOL Test'';
  1219 
  1220 * system: smart selection of Isabelle process versus Isabelle
  1221 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1222 run both "isabelle" and "Isabelle" even if file names are badly
  1223 damaged (executable inspects the case of the first letter of its own
  1224 name); added separate "isabelle-process" and "isabelle-interface";
  1225 
  1226 * system: refrain from any attempt at filtering input streams; no
  1227 longer support ``8bit'' encoding of old isabelle font, instead proper
  1228 iso-latin characters may now be used; the related isatools
  1229 "symbolinput" and "nonascii" have disappeared as well;
  1230 
  1231 * system: removed old "xterm" interface (the print modes "xterm" and
  1232 "xterm_color" are still available for direct use in a suitable
  1233 terminal);
  1234 
  1235 
  1236 
  1237 New in Isabelle99-2 (February 2001)
  1238 -----------------------------------
  1239 
  1240 *** Overview of INCOMPATIBILITIES ***
  1241 
  1242 * HOL: please note that theories in the Library and elsewhere often use the
  1243 new-style (Isar) format; to refer to their theorems in an ML script you must
  1244 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1245 
  1246 * HOL: inductive package no longer splits induction rule aggressively,
  1247 but only as far as specified by the introductions given; the old
  1248 format may be recovered via ML function complete_split_rule or attribute
  1249 'split_rule (complete)';
  1250 
  1251 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1252 gfp_Tarski to gfp_unfold;
  1253 
  1254 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1255 
  1256 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1257 relation); infix "^^" has been renamed "``"; infix "``" has been
  1258 renamed "`"; "univalent" has been renamed "single_valued";
  1259 
  1260 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1261 operation;
  1262 
  1263 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1264 
  1265 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1266 
  1267 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1268 consequence, it is no longer monotonic wrt. the local goal context
  1269 (which is now passed through the inductive cases);
  1270 
  1271 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1272 \<gg> to \<ggreater>;
  1273 
  1274 
  1275 *** Document preparation ***
  1276 
  1277 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1278 available: are "it" for near math-mode best-style output, "sl" for
  1279 slanted text style, and "tt" for plain type-writer; if no
  1280 \isabellestyle command is given, output is according to slanted
  1281 type-writer);
  1282 
  1283 * support sub/super scripts (for single symbols only), input syntax is
  1284 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1285 
  1286 * some more standard symbols; see Appendix A of the system manual for
  1287 the complete list of symbols defined in isabellesym.sty;
  1288 
  1289 * improved isabelle style files; more abstract symbol implementation
  1290 (should now use \isamath{...} and \isatext{...} in custom symbol
  1291 definitions);
  1292 
  1293 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1294 state; Note that presentation of goal states does not conform to
  1295 actual human-readable proof documents.  Please do not include goal
  1296 states into document output unless you really know what you are doing!
  1297 
  1298 * proper indentation of antiquoted output with proportional LaTeX
  1299 fonts;
  1300 
  1301 * no_document ML operator temporarily disables LaTeX document
  1302 generation;
  1303 
  1304 * isatool unsymbolize tunes sources for plain ASCII communication;
  1305 
  1306 
  1307 *** Isar ***
  1308 
  1309 * Pure: Isar now suffers initial goal statements to contain unbound
  1310 schematic variables (this does not conform to actual readable proof
  1311 documents, due to unpredictable outcome and non-compositional proof
  1312 checking); users who know what they are doing may use schematic goals
  1313 for Prolog-style synthesis of proven results;
  1314 
  1315 * Pure: assumption method (an implicit finishing) now handles actual
  1316 rules as well;
  1317 
  1318 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1319 initial goal, declare "that" only as Pure intro (only for single
  1320 steps); the "that" rule assumption may now be involved in implicit
  1321 finishing, thus ".." becomes a feasible for trivial obtains;
  1322 
  1323 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1324 instance proofs may be performed by "..";
  1325 
  1326 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1327 statements as well;
  1328 
  1329 * Pure: more robust selection of calculational rules;
  1330 
  1331 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1332 rule (as well as the assumption rule);
  1333 
  1334 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1335 lemmas, using the graph browser tool;
  1336 
  1337 * Pure: predict failure of "show" in interactive mode;
  1338 
  1339 * Pure: 'thms_containing' now takes actual terms as arguments;
  1340 
  1341 * HOL: improved method 'induct' --- now handles non-atomic goals
  1342 (potential INCOMPATIBILITY); tuned error handling;
  1343 
  1344 * HOL: cases and induct rules now provide explicit hints about the
  1345 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1346 any remaining facts are inserted into the goal verbatim;
  1347 
  1348 * HOL: local contexts (aka cases) may now contain term bindings as
  1349 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1350 the result to be shown in each case;
  1351 
  1352 * HOL: added 'recdef_tc' command;
  1353 
  1354 * isatool convert assists in eliminating legacy ML scripts;
  1355 
  1356 
  1357 *** HOL ***
  1358 
  1359 * HOL/Library: a collection of generic theories to be used together
  1360 with main HOL; the theory loader path already includes this directory
  1361 by default; the following existing theories have been moved here:
  1362 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1363 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1364 
  1365 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1366 modelling and verification task performed in Isabelle/HOL +
  1367 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1368 
  1369 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1370 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1371 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1372 'domain', this makes the theory consistent with mathematical
  1373 literature;
  1374 
  1375 * HOL basics: added overloaded operations "inverse" and "divide"
  1376 (infix "/"), syntax for generic "abs" operation, generic summation
  1377 operator \<Sum>;
  1378 
  1379 * HOL/typedef: simplified package, provide more useful rules (see also
  1380 HOL/subset.thy);
  1381 
  1382 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1383 now expressed as a proper nested rule (old-style tactic scripts may
  1384 require atomize_strip_tac to cope with non-atomic premises);
  1385 
  1386 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1387 to "split_conv" (old name still available for compatibility);
  1388 
  1389 * HOL: improved concrete syntax for strings (e.g. allows translation
  1390 rules with string literals);
  1391 
  1392 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1393  and Fleuriot's mechanization of analysis, including the transcendental
  1394  functions for the reals;
  1395 
  1396 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1397 
  1398 
  1399 *** CTT ***
  1400 
  1401 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1402 "lam" is displayed as TWO lambda-symbols
  1403 
  1404 * CTT: theory Main now available, containing everything (that is, Bool
  1405 and Arith);
  1406 
  1407 
  1408 *** General ***
  1409 
  1410 * Pure: the Simplifier has been implemented properly as a derived rule
  1411 outside of the actual kernel (at last!); the overall performance
  1412 penalty in practical applications is about 50%, while reliability of
  1413 the Isabelle inference kernel has been greatly improved;
  1414 
  1415 * print modes "brackets" and "no_brackets" control output of nested =>
  1416 (types) and ==> (props); the default behaviour is "brackets";
  1417 
  1418 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1419 as assumptions as well;
  1420 
  1421 * system: support Poly/ML 4.0;
  1422 
  1423 * system: isatool install handles KDE version 1 or 2;
  1424 
  1425 
  1426 
  1427 New in Isabelle99-1 (October 2000)
  1428 ----------------------------------
  1429 
  1430 *** Overview of INCOMPATIBILITIES ***
  1431 
  1432 * HOL: simplification of natural numbers is much changed; to partly
  1433 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1434 issue the following ML commands:
  1435 
  1436   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1437   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1438 
  1439 * HOL: simplification no longer dives into case-expressions; this is
  1440 controlled by "t.weak_case_cong" for each datatype t;
  1441 
  1442 * HOL: nat_less_induct renamed to less_induct;
  1443 
  1444 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1445 fixsome to patch .thy and .ML sources automatically;
  1446 
  1447   select_equality  -> some_equality
  1448   select_eq_Ex     -> some_eq_ex
  1449   selectI2EX       -> someI2_ex
  1450   selectI2         -> someI2
  1451   selectI          -> someI
  1452   select1_equality -> some1_equality
  1453   Eps_sym_eq       -> some_sym_eq_trivial
  1454   Eps_eq           -> some_eq_trivial
  1455 
  1456 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1457 
  1458 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1459 instead);
  1460 
  1461 * HOL: the recursion equations generated by 'recdef' are now called
  1462 f.simps instead of f.rules;
  1463 
  1464 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1465 
  1466 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1467 sometimes be needed;
  1468 
  1469 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1470 
  1471 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1472 
  1473 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1474 product is now "<*>" instead of "Times"; the lexicographic product is
  1475 now "<*lex*>" instead of "**";
  1476 
  1477 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1478 of main HOL, but was unused); better use HOL's datatype package;
  1479 
  1480 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1481 the old syntax may be recovered as follows:
  1482 
  1483   syntax (symbols)
  1484     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1485       (infixl "\\<oplus>" 100)
  1486 
  1487 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1488 
  1489 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1490 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1491 internally;
  1492 
  1493 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1494 changed from A/r to A//r;
  1495 
  1496 * ZF: new treatment of arithmetic (nat & int) may break some old
  1497 proofs;
  1498 
  1499 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1500 rulify -> rule_format, elimify -> elim_format, ...);
  1501 
  1502 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1503 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1504 should have to change intro!! to intro? only); replaced "delrule" by
  1505 "rule del";
  1506 
  1507 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1508 
  1509 * Provers: strengthened force_tac by using new first_best_tac;
  1510 
  1511 * LaTeX document preparation: several changes of isabelle.sty (see
  1512 lib/texinputs);
  1513 
  1514 
  1515 *** Document preparation ***
  1516 
  1517 * formal comments (text blocks etc.) in new-style theories may now
  1518 contain antiquotations of thm/prop/term/typ/text to be presented
  1519 according to latex print mode; concrete syntax is like this:
  1520 @{term[show_types] "f(x) = a + x"};
  1521 
  1522 * isatool mkdir provides easy setup of Isabelle session directories,
  1523 including proper document sources;
  1524 
  1525 * generated LaTeX sources are now deleted after successful run
  1526 (isatool document -c); may retain a copy somewhere else via -D option
  1527 of isatool usedir;
  1528 
  1529 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1530 style files, achieving self-contained LaTeX sources and simplifying
  1531 LaTeX debugging;
  1532 
  1533 * old-style theories now produce (crude) LaTeX output as well;
  1534 
  1535 * browser info session directories are now self-contained (may be put
  1536 on WWW server seperately); improved graphs of nested sessions; removed
  1537 graph for 'all sessions';
  1538 
  1539 * several improvements in isabelle style files; \isabellestyle{it}
  1540 produces fake math mode output; \isamarkupheader is now \section by
  1541 default; see lib/texinputs/isabelle.sty etc.;
  1542 
  1543 
  1544 *** Isar ***
  1545 
  1546 * Isar/Pure: local results and corresponding term bindings are now
  1547 subject to Hindley-Milner polymorphism (similar to ML); this
  1548 accommodates incremental type-inference very nicely;
  1549 
  1550 * Isar/Pure: new derived language element 'obtain' supports
  1551 generalized existence reasoning;
  1552 
  1553 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1554 support accumulation of results, without applying any rules yet;
  1555 useful to collect intermediate results without explicit name
  1556 references, and for use with transitivity rules with more than 2
  1557 premises;
  1558 
  1559 * Isar/Pure: scalable support for case-analysis type proofs: new
  1560 'case' language element refers to local contexts symbolically, as
  1561 produced by certain proof methods; internally, case names are attached
  1562 to theorems as "tags";
  1563 
  1564 * Isar/Pure: theory command 'hide' removes declarations from
  1565 class/type/const name spaces;
  1566 
  1567 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1568 indicate potential overloading;
  1569 
  1570 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1571 
  1572 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1573 "{a,b,c}" instead of {a,b,c};
  1574 
  1575 * Isar/Pure now provides its own version of intro/elim/dest
  1576 attributes; useful for building new logics, but beware of confusion
  1577 with the version in Provers/classical;
  1578 
  1579 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1580 case name 'antecedent';
  1581 
  1582 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1583 to the current context is now done automatically);
  1584 
  1585 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1586 for definining proof methods in ML;
  1587 
  1588 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1589 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1590 most cases, one should have to change intro!! to intro? only);
  1591 replaced "delrule" by "rule del";
  1592 
  1593 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1594 'symmetric' attribute (the latter supercedes [RS sym]);
  1595 
  1596 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1597 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1598 well (including splits);
  1599 
  1600 * Isar/Provers: Simplifier and Classical methods now support all kind
  1601 of modifiers used in the past, including 'cong', 'iff', etc.
  1602 
  1603 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1604 of Simplifier and Classical reasoner);
  1605 
  1606 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1607 now support named cases; major packages (inductive, datatype, primrec,
  1608 recdef) support case names and properly name parameters;
  1609 
  1610 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1611 monotonicity conditions are extracted to be proven at end of
  1612 calculations;
  1613 
  1614 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1615 method anyway;
  1616 
  1617 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1618 split_if split_if_asm; datatype package provides theorems foo.splits =
  1619 foo.split foo.split_asm for each datatype;
  1620 
  1621 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1622 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1623 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1624 use "(cases (simplified))" method in proper proof texts);
  1625 
  1626 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1627 
  1628 * Isar: names of theorems etc. may be natural numbers as well;
  1629 
  1630 * Isar: 'pr' command: optional arguments for goals_limit and
  1631 ProofContext.prems_limit; no longer prints theory contexts, but only
  1632 proof states;
  1633 
  1634 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1635 additional print modes to be specified; e.g. "pr(latex)" will print
  1636 proof state according to the Isabelle LaTeX style;
  1637 
  1638 * Isar: improved support for emulating tactic scripts, including proof
  1639 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1640 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1641 (for HOL datatypes);
  1642 
  1643 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1644 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1645 'proof method scripts' have to be in depth-first order;
  1646 
  1647 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1648 
  1649 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1650 should instead use individual commands for printing items
  1651 (print_commands, print_methods etc.);
  1652 
  1653 * Isar: added 'nothing' --- the empty list of theorems;
  1654 
  1655 
  1656 *** HOL ***
  1657 
  1658 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1659 corresponding virtual machine and a specification of its bytecode
  1660 verifier and a lightweight bytecode verifier, including proofs of
  1661 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1662 Cornelia Pusch (see also the homepage of project Bali at
  1663 http://isabelle.in.tum.de/Bali/);
  1664 
  1665 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1666 Clemens Ballarin;
  1667 
  1668 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1669 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1670 Rasmussen;
  1671 
  1672 * HOL/Lattice: fundamental concepts of lattice theory and order
  1673 structures, including duals, properties of bounds versus algebraic
  1674 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1675 Theorem for complete lattices etc.; may also serve as a demonstration
  1676 for abstract algebraic reasoning using axiomatic type classes, and
  1677 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1678 
  1679 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1680 von Oheimb;
  1681 
  1682 * HOL/IMPP: extension of IMP with local variables and mutually
  1683 recursive procedures, by David von Oheimb;
  1684 
  1685 * HOL/Lambda: converted into new-style theory and document;
  1686 
  1687 * HOL/ex/Multiquote: example of multiple nested quotations and
  1688 anti-quotations -- basically a generalized version of de-Bruijn
  1689 representation; very useful in avoiding lifting of operations;
  1690 
  1691 * HOL/record: added general record equality rule to simpset; fixed
  1692 select-update simplification procedure to handle extended records as
  1693 well; admit "r" as field name;
  1694 
  1695 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1696 other numeric types and also as the identity of groups, rings, etc.;
  1697 
  1698 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1699 Types nat and int belong to this axclass;
  1700 
  1701 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1702    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1703    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1704   two terms #m*u and #n*u are replaced by #(m+n)*u
  1705     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1706   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1707     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1708 
  1709 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1710 powerful prover for predicate logic but knows nothing of clasets; see
  1711 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1712 
  1713 * HOL: new version of "case_tac" subsumes both boolean case split and
  1714 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1715 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1716 
  1717 * HOL: simplification no longer dives into case-expressions: only the
  1718 selector expression is simplified, but not the remaining arms; to
  1719 enable full simplification of case-expressions for datatype t, you may
  1720 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1721 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1722 
  1723 * HOL/recdef: the recursion equations generated by 'recdef' for
  1724 function 'f' are now called f.simps instead of f.rules; if all
  1725 termination conditions are proved automatically, these simplification
  1726 rules are added to the simpset, as in primrec; rules may be named
  1727 individually as well, resulting in a separate list of theorems for
  1728 each equation;
  1729 
  1730 * HOL/While is a new theory that provides a while-combinator. It
  1731 permits the definition of tail-recursive functions without the
  1732 provision of a termination measure. The latter is necessary once the
  1733 invariant proof rule for while is applied.
  1734 
  1735 * HOL: new (overloaded) notation for the set of elements below/above
  1736 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1737 
  1738 * HOL: theorems impI, allI, ballI bound as "strip";
  1739 
  1740 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1741 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1742 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1743 
  1744 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1745 
  1746 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1747 main HOL, but was unused);
  1748 
  1749 * HOL: fewer consts declared as global (e.g. have to refer to
  1750 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1751 
  1752 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1753 in case of overlap with user translations (e.g. judgements over
  1754 tuples); (note that the underlying logical represenation is still
  1755 bogus);
  1756 
  1757 
  1758 *** ZF ***
  1759 
  1760 * ZF: simplification automatically cancels common terms in arithmetic
  1761 expressions over nat and int;
  1762 
  1763 * ZF: new treatment of nat to minimize type-checking: all operators
  1764 coerce their operands to a natural number using the function natify,
  1765 making the algebraic laws unconditional;
  1766 
  1767 * ZF: as above, for int: operators coerce their operands to an integer
  1768 using the function intify;
  1769 
  1770 * ZF: the integer library now contains many of the usual laws for the
  1771 orderings, including $<=, and monotonicity laws for $+ and $*;
  1772 
  1773 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1774 simplification;
  1775 
  1776 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1777 to the simplifier and classical reasoner simultaneously;
  1778 
  1779 
  1780 *** General ***
  1781 
  1782 * Provers: blast_tac now handles actual object-logic rules as
  1783 assumptions; note that auto_tac uses blast_tac internally as well;
  1784 
  1785 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1786 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1787 
  1788 * Provers: delrules now handles destruct rules as well (no longer need
  1789 explicit make_elim);
  1790 
  1791 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1792   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1793 use instead the strong form,
  1794   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1795 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1796 from destruct-rules;
  1797 
  1798 * Provers: Simplifier.easy_setup provides a fast path to basic
  1799 Simplifier setup for new object-logics;
  1800 
  1801 * Pure: AST translation rules no longer require constant head on LHS;
  1802 
  1803 * Pure: improved name spaces: ambiguous output is qualified; support
  1804 for hiding of names;
  1805 
  1806 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1807 XSYMBOL_HOME; no longer need to do manual configuration in most
  1808 situations;
  1809 
  1810 * system: compression of ML heaps images may now be controlled via -c
  1811 option of isabelle and isatool usedir (currently only observed by
  1812 Poly/ML);
  1813 
  1814 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1815 useful for remote X11);
  1816 
  1817 * system: provide TAGS file for Isabelle sources;
  1818 
  1819 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1820 order;
  1821 
  1822 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1823 timing flag supersedes proof_timing and Toplevel.trace;
  1824 
  1825 * ML: new combinators |>> and |>>> for incremental transformations
  1826 with secondary results (e.g. certain theory extensions):
  1827 
  1828 * ML: PureThy.add_defs gets additional argument to indicate potential
  1829 overloading (usually false);
  1830 
  1831 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1832 results;
  1833 
  1834 
  1835 
  1836 New in Isabelle99 (October 1999)
  1837 --------------------------------
  1838 
  1839 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1840 
  1841 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1842 are no longer simplified.  (This allows the simplifier to unfold recursive
  1843 functional programs.)  To restore the old behaviour, declare
  1844 
  1845     Delcongs [if_weak_cong];
  1846 
  1847 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1848 complement;
  1849 
  1850 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1851 
  1852 * HOL/datatype: mutual_induct_tac no longer exists --
  1853   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1854 
  1855 * HOL/typedef: fixed type inference for representing set; type
  1856 arguments now have to occur explicitly on the rhs as type constraints;
  1857 
  1858 * ZF: The con_defs part of an inductive definition may no longer refer
  1859 to constants declared in the same theory;
  1860 
  1861 * HOL, ZF: the function mk_cases, generated by the inductive
  1862 definition package, has lost an argument.  To simplify its result, it
  1863 uses the default simpset instead of a supplied list of theorems.
  1864 
  1865 * HOL/List: the constructors of type list are now Nil and Cons;
  1866 
  1867 * Simplifier: the type of the infix ML functions
  1868         setSSolver addSSolver setSolver addSolver
  1869 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1870 for packaging solvers. A solver is created via
  1871         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1872 where the string argument is only a comment.
  1873 
  1874 
  1875 *** Proof tools ***
  1876 
  1877 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1878 decision procedure for linear arithmetic. Currently it is used for
  1879 types `nat', `int', and `real' in HOL (see below); it can, should and
  1880 will be instantiated for other types and logics as well.
  1881 
  1882 * The simplifier now accepts rewrite rules with flexible heads, eg
  1883      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1884   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1885   matching.
  1886 
  1887 
  1888 *** General ***
  1889 
  1890 * New Isabelle/Isar subsystem provides an alternative to traditional
  1891 tactical theorem proving; together with the ProofGeneral/isar user
  1892 interface it offers an interactive environment for developing human
  1893 readable proof documents (Isar == Intelligible semi-automated
  1894 reasoning); for further information see isatool doc isar-ref,
  1895 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1896 
  1897 * improved and simplified presentation of theories: better HTML markup
  1898 (including colors), graph views in several sizes; isatool usedir now
  1899 provides a proper interface for user theories (via -P option); actual
  1900 document preparation based on (PDF)LaTeX is available as well (for
  1901 new-style theories only); see isatool doc system for more information;
  1902 
  1903 * native support for Proof General, both for classic Isabelle and
  1904 Isabelle/Isar;
  1905 
  1906 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1907 using the graph browser tool;
  1908 
  1909 * Isabelle manuals now also available as PDF;
  1910 
  1911 * theory loader rewritten from scratch (may not be fully
  1912 bug-compatible); old loadpath variable has been replaced by show_path,
  1913 add_path, del_path, reset_path functions; new operations such as
  1914 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1915 isatool doc ref);
  1916 
  1917 * improved isatool install: option -k creates KDE application icon,
  1918 option -p DIR installs standalone binaries;
  1919 
  1920 * added ML_PLATFORM setting (useful for cross-platform installations);
  1921 more robust handling of platform specific ML images for SML/NJ;
  1922 
  1923 * the settings environment is now statically scoped, i.e. it is never
  1924 created again in sub-processes invoked from isabelle, isatool, or
  1925 Isabelle;
  1926 
  1927 * path element specification '~~' refers to '$ISABELLE_HOME';
  1928 
  1929 * in locales, the "assumes" and "defines" parts may be omitted if
  1930 empty;
  1931 
  1932 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1933 long arrows);
  1934 
  1935 * new print_mode "HTML";
  1936 
  1937 * new flag show_tags controls display of tags of theorems (which are
  1938 basically just comments that may be attached by some tools);
  1939 
  1940 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1941 mode and goal output format:
  1942 
  1943 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1944 244c244
  1945 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1946 ---
  1947 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1948 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1949 181c181
  1950 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1951 ---
  1952 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1953 
  1954 * function bind_thms stores lists of theorems (cf. bind_thm);
  1955 
  1956 * new shorthand tactics ftac, eatac, datac, fatac;
  1957 
  1958 * qed (and friends) now accept "" as result name; in that case the
  1959 theorem is not stored, but proper checks and presentation of the
  1960 result still apply;
  1961 
  1962 * theorem database now also indexes constants "Trueprop", "all",
  1963 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1964 
  1965 
  1966 *** HOL ***
  1967 
  1968 ** HOL arithmetic **
  1969 
  1970 * There are now decision procedures for linear arithmetic over nat and
  1971 int:
  1972 
  1973 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  1974 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  1975 are treated as atomic; subformulae not involving type `nat' or `int'
  1976 are ignored; quantified subformulae are ignored unless they are
  1977 positive universal or negative existential. The tactic has to be
  1978 invoked by hand and can be a little bit slow. In particular, the
  1979 running time is exponential in the number of occurrences of `min' and
  1980 `max', and `-' on `nat'.
  1981 
  1982 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  1983 (negated) (in)equalities among the premises and the conclusion into
  1984 account (i.e. no compound formulae) and does not know about `min' and
  1985 `max', and `-' on `nat'. It is fast and is used automatically by the
  1986 simplifier.
  1987 
  1988 NB: At the moment, these decision procedures do not cope with mixed
  1989 nat/int formulae where the two parts interact, such as `m < n ==>
  1990 int(m) < int(n)'.
  1991 
  1992 * HOL/Numeral provides a generic theory of numerals (encoded
  1993 efficiently as bit strings); setup for types nat/int/real is in place;
  1994 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  1995 int, existing theories and proof scripts may require a few additional
  1996 type constraints;
  1997 
  1998 * integer division and remainder can now be performed on constant
  1999 arguments;
  2000 
  2001 * many properties of integer multiplication, division and remainder
  2002 are now available;
  2003 
  2004 * An interface to the Stanford Validity Checker (SVC) is available through the
  2005 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2006 are proved automatically.  SVC must be installed separately, and its results
  2007 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2008 invocation of the underlying oracle).  For SVC see
  2009   http://verify.stanford.edu/SVC
  2010 
  2011 * IsaMakefile: the HOL-Real target now builds an actual image;
  2012 
  2013 
  2014 ** HOL misc **
  2015 
  2016 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2017 (in Isabelle/Isar) -- by Gertrud Bauer;
  2018 
  2019 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2020 analysis for assembly languages with subtypes;
  2021 
  2022 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2023 -- avoids syntactic ambiguities and treats state, transition, and
  2024 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2025 changed syntax and (many) tactics;
  2026 
  2027 * HOL/inductive: Now also handles more general introduction rules such
  2028   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2029   theorems are now maintained within the theory (maintained via the
  2030   "mono" attribute);
  2031 
  2032 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2033   (using function types) such as
  2034 
  2035   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2036 
  2037 * HOL/record: record_simproc (part of the default simpset) takes care
  2038 of selectors applied to updated records; record_split_tac is no longer
  2039 part of the default claset; update_defs may now be removed from the
  2040 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2041 
  2042   claset_ref () := claset() addSWrapper record_split_wrapper;
  2043   Delsimprocs [record_simproc]
  2044 
  2045 * HOL/typedef: fixed type inference for representing set; type
  2046 arguments now have to occur explicitly on the rhs as type constraints;
  2047 
  2048 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2049 names rather than an ML expression;
  2050 
  2051 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2052 supplied later.  Program schemes can be defined, such as
  2053     "While B C s = (if B s then While B C (C s) else s)"
  2054 where the well-founded relation can be chosen after B and C have been given.
  2055 
  2056 * HOL/List: the constructors of type list are now Nil and Cons;
  2057 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2058 course, ML tools referring to List.list.op # etc. have to be adapted;
  2059 
  2060 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2061 disabled by default; run isabelle with option -m HOL to get back to
  2062 the original Gordon/HOL-style output;
  2063 
  2064 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2065 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2066 
  2067 * HOL basic syntax simplified (more orthogonal): all variants of
  2068 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2069 Eps operator is provided as well: "SOME x. P[x]";
  2070 
  2071 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2072 
  2073 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2074 thus available for user theories;
  2075 
  2076 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2077 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2078 time;
  2079 
  2080 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2081 several times and then mp;
  2082 
  2083 
  2084 *** LK ***
  2085 
  2086 * the notation <<...>> is now available as a notation for sequences of
  2087 formulas;
  2088 
  2089 * the simplifier is now installed
  2090 
  2091 * the axiom system has been generalized (thanks to Soren Heilmann)
  2092 
  2093 * the classical reasoner now has a default rule database
  2094 
  2095 
  2096 *** ZF ***
  2097 
  2098 * new primrec section allows primitive recursive functions to be given
  2099 directly (as in HOL) over datatypes and the natural numbers;
  2100 
  2101 * new tactics induct_tac and exhaust_tac for induction (or case
  2102 analysis) over datatypes and the natural numbers;
  2103 
  2104 * the datatype declaration of type T now defines the recursor T_rec;
  2105 
  2106 * simplification automatically does freeness reasoning for datatype
  2107 constructors;
  2108 
  2109 * automatic type-inference, with AddTCs command to insert new
  2110 type-checking rules;
  2111 
  2112 * datatype introduction rules are now added as Safe Introduction rules
  2113 to the claset;
  2114 
  2115 * the syntax "if P then x else y" is now available in addition to
  2116 if(P,x,y);
  2117 
  2118 
  2119 *** Internal programming interfaces ***
  2120 
  2121 * tuned simplifier trace output; new flag debug_simp;
  2122 
  2123 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2124 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2125 
  2126 * AxClass.axclass_tac lost the theory argument;
  2127 
  2128 * tuned current_goals_markers semantics: begin / end goal avoids
  2129 printing empty lines;
  2130 
  2131 * removed prs and prs_fn hook, which was broken because it did not
  2132 include \n in its semantics, forcing writeln to add one
  2133 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2134 string -> unit if you really want to output text without newline;
  2135 
  2136 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2137 plain output, interface builders may have to enable 'isabelle_font'
  2138 mode to get Isabelle font glyphs as before;
  2139 
  2140 * refined token_translation interface; INCOMPATIBILITY: output length
  2141 now of type real instead of int;
  2142 
  2143 * theory loader actions may be traced via new ThyInfo.add_hook
  2144 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2145 your own database of information attached to *whole* theories -- as
  2146 opposed to intra-theory data slots offered via TheoryDataFun;
  2147 
  2148 * proper handling of dangling sort hypotheses (at last!);
  2149 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2150 extra sort hypotheses that can be witnessed from the type signature;
  2151 the force_strip_shyps flag is gone, any remaining shyps are simply
  2152 left in the theorem (with a warning issued by strip_shyps_warning);
  2153 
  2154 
  2155 
  2156 New in Isabelle98-1 (October 1998)
  2157 ----------------------------------
  2158 
  2159 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2160 
  2161 * several changes of automated proof tools;
  2162 
  2163 * HOL: major changes to the inductive and datatype packages, including
  2164 some minor incompatibilities of theory syntax;
  2165 
  2166 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2167 called `inj_on';
  2168 
  2169 * HOL: removed duplicate thms in Arith:
  2170   less_imp_add_less  should be replaced by  trans_less_add1
  2171   le_imp_add_le      should be replaced by  trans_le_add1
  2172 
  2173 * HOL: unary minus is now overloaded (new type constraints may be
  2174 required);
  2175 
  2176 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2177 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2178 now taken as an integer constant.
  2179 
  2180 * Pure: ML function 'theory_of' renamed to 'theory';
  2181 
  2182 
  2183 *** Proof tools ***
  2184 
  2185 * Simplifier:
  2186   1. Asm_full_simp_tac is now more aggressive.
  2187      1. It will sometimes reorient premises if that increases their power to
  2188         simplify.
  2189      2. It does no longer proceed strictly from left to right but may also
  2190         rotate premises to achieve further simplification.
  2191      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2192      old Asm_full_simp_tac in that it does not rotate premises.
  2193   2. The simplifier now knows a little bit about nat-arithmetic.
  2194 
  2195 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2196 allows for selected deletion of wrappers, by introduction of names for
  2197 wrapper functionals.  This implies that addbefore, addSbefore,
  2198 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2199 and that adding two tactics with the same name overwrites the first
  2200 one (emitting a warning).
  2201   type wrapper = (int -> tactic) -> (int -> tactic)
  2202   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2203   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2204   delWrapper, delSWrapper: claset *  string            -> claset
  2205   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2206 
  2207 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2208 semantics; addbefore now affects only the unsafe part of step_tac
  2209 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2210 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2211 by Force_tac;
  2212 
  2213 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2214 compWrapper; added safe wrapper (and access functions for it);
  2215 
  2216 * HOL/split_all_tac is now much faster and fails if there is nothing
  2217 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2218 and the names of the automatically generated variables have changed.
  2219 split_all_tac has moved within claset() from unsafe wrappers to safe
  2220 wrappers, which means that !!-bound variables are split much more
  2221 aggressively, and safe_tac and clarify_tac now split such variables.
  2222 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2223 Note: the same holds for record_split_tac, which does the job of
  2224 split_all_tac for record fields.
  2225 
  2226 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2227 permanently to the default simpset using Addsplits just like
  2228 Addsimps. They can be removed via Delsplits just like
  2229 Delsimps. Lower-case versions are also available.
  2230 
  2231 * HOL/Simplifier: The rule split_if is now part of the default
  2232 simpset. This means that the simplifier will eliminate all occurrences
  2233 of if-then-else in the conclusion of a goal. To prevent this, you can
  2234 either remove split_if completely from the default simpset by
  2235 `Delsplits [split_if]' or remove it in a specific call of the
  2236 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2237 other case splitting rules to/from the default simpset: every datatype
  2238 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2239 t is the name of the datatype).
  2240 
  2241 * Classical reasoner / Simplifier combination: new force_tac (and
  2242 derivatives Force_tac, force) combines rewriting and classical
  2243 reasoning (and whatever other tools) similarly to auto_tac, but is
  2244 aimed to solve the given subgoal completely.
  2245 
  2246 
  2247 *** General ***
  2248 
  2249 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2250 and `goalw': the theory is no longer needed as an explicit argument -
  2251 the current theory context is used; assumptions are no longer returned
  2252 at the ML-level unless one of them starts with ==> or !!; it is
  2253 recommended to convert to these new commands using isatool fixgoal
  2254 (backup your sources first!);
  2255 
  2256 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2257 the current theory context, and 'theory' to lookup stored theories;
  2258 
  2259 * new theory section 'locale' for declaring constants, assumptions and
  2260 definitions that have local scope;
  2261 
  2262 * new theory section 'nonterminals' for purely syntactic types;
  2263 
  2264 * new theory section 'setup' for generic ML setup functions
  2265 (e.g. package initialization);
  2266 
  2267 * the distribution now includes Isabelle icons: see
  2268 lib/logo/isabelle-{small,tiny}.xpm;
  2269 
  2270 * isatool install - install binaries with absolute references to
  2271 ISABELLE_HOME/bin;
  2272 
  2273 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2274 
  2275 * print mode 'emacs' reserved for Isamode;
  2276 
  2277 * support multiple print (ast) translations per constant name;
  2278 
  2279 * theorems involving oracles are now printed with a suffixed [!];
  2280 
  2281 
  2282 *** HOL ***
  2283 
  2284 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2285 
  2286 * HOL/inductive package reorganized and improved: now supports mutual
  2287 definitions such as
  2288 
  2289   inductive EVEN ODD
  2290     intrs
  2291       null "0 : EVEN"
  2292       oddI "n : EVEN ==> Suc n : ODD"
  2293       evenI "n : ODD ==> Suc n : EVEN"
  2294 
  2295 new theorem list "elims" contains an elimination rule for each of the
  2296 recursive sets; inductive definitions now handle disjunctive premises
  2297 correctly (also ZF);
  2298 
  2299 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2300 "mutual_induct" no longer exists - the induction rule is always
  2301 contained in "induct";
  2302 
  2303 
  2304 * HOL/datatype package re-implemented and greatly improved: now
  2305 supports mutually recursive datatypes such as
  2306 
  2307   datatype
  2308     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2309             | SUM ('a aexp) ('a aexp)
  2310             | DIFF ('a aexp) ('a aexp)
  2311             | NUM 'a
  2312   and
  2313     'a bexp = LESS ('a aexp) ('a aexp)
  2314             | AND ('a bexp) ('a bexp)
  2315             | OR ('a bexp) ('a bexp)
  2316 
  2317 as well as indirectly recursive datatypes such as
  2318 
  2319   datatype
  2320     ('a, 'b) term = Var 'a
  2321                   | App 'b ((('a, 'b) term) list)
  2322 
  2323 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2324 induction on mutually / indirectly recursive datatypes.
  2325 
  2326 Primrec equations are now stored in theory and can be accessed via
  2327 <function_name>.simps.
  2328 
  2329 INCOMPATIBILITIES:
  2330 
  2331   - Theories using datatypes must now have theory Datatype as an
  2332     ancestor.
  2333   - The specific <typename>.induct_tac no longer exists - use the
  2334     generic induct_tac instead.
  2335   - natE has been renamed to nat.exhaust - use exhaust_tac
  2336     instead of res_inst_tac ... natE. Note that the variable
  2337     names in nat.exhaust differ from the names in natE, this
  2338     may cause some "fragile" proofs to fail.
  2339   - The theorems split_<typename>_case and split_<typename>_case_asm
  2340     have been renamed to <typename>.split and <typename>.split_asm.
  2341   - Since default sorts of type variables are now handled correctly,
  2342     some datatype definitions may have to be annotated with explicit
  2343     sort constraints.
  2344   - Primrec definitions no longer require function name and type
  2345     of recursive argument.
  2346 
  2347 Consider using isatool fixdatatype to adapt your theories and proof
  2348 scripts to the new package (backup your sources first!).
  2349 
  2350 
  2351 * HOL/record package: considerably improved implementation; now
  2352 includes concrete syntax for record types, terms, updates; theorems
  2353 for surjective pairing and splitting !!-bound record variables; proof
  2354 support is as follows:
  2355 
  2356   1) standard conversions (selectors or updates applied to record
  2357 constructor terms) are part of the standard simpset;
  2358 
  2359   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2360 made part of standard simpset and claset via addIffs;
  2361 
  2362   3) a tactic for record field splitting (record_split_tac) is part of
  2363 the standard claset (addSWrapper);
  2364 
  2365 To get a better idea about these rules you may retrieve them via
  2366 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2367 the name of your record type.
  2368 
  2369 The split tactic 3) conceptually simplifies by the following rule:
  2370 
  2371   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2372 
  2373 Thus any record variable that is bound by meta-all will automatically
  2374 blow up into some record constructor term, consequently the
  2375 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2376 solve record problems automatically.
  2377 
  2378 
  2379 * reorganized the main HOL image: HOL/Integ and String loaded by
  2380 default; theory Main includes everything;
  2381 
  2382 * automatic simplification of integer sums and comparisons, using cancellation;
  2383 
  2384 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2385 
  2386 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2387 
  2388 * many new identities for unions, intersections, set difference, etc.;
  2389 
  2390 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2391 called split_if, split_split, split_sum_case and split_nat_case (to go
  2392 with add/delsplits);
  2393 
  2394 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2395 (?x::unit) = (); this is made part of the default simpset, which COULD
  2396 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2397 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2398 unit_abs_eta_conv is added in order to counter the effect of
  2399 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2400 %u.f();
  2401 
  2402 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2403 makes more sense);
  2404 
  2405 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2406   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2407   disjointness reasoning but breaking a few old proofs.
  2408 
  2409 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2410 to 'converse' from 'inverse' (for compatibility with ZF and some
  2411 literature);
  2412 
  2413 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2414 the well-founded relation;
  2415 
  2416 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2417     Compl A.  The "Compl" syntax remains available as input syntax for this
  2418     release ONLY.
  2419 
  2420 * HOL/Update: new theory of function updates:
  2421     f(a:=b) == %x. if x=a then b else f x
  2422 may also be iterated as in f(a:=b,c:=d,...);
  2423 
  2424 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2425 
  2426 * HOL/List:
  2427   - new function list_update written xs[i:=v] that updates the i-th
  2428     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2429   - new function `upt' written [i..j(] which generates the list
  2430     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2431     bound write [i..j], which is a shorthand for [i..j+1(].
  2432   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2433 
  2434 * HOL/Arith:
  2435   - removed 'pred' (predecessor) function;
  2436   - generalized some theorems about n-1;
  2437   - many new laws about "div" and "mod";
  2438   - new laws about greatest common divisors (see theory ex/Primes);
  2439 
  2440 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2441 instead of "inverse";
  2442 
  2443 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2444   of the multiset ordering;
  2445 
  2446 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2447   (not included by default);
  2448 
  2449 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2450 
  2451 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2452   programs, i.e. different program variables may have different types.
  2453 
  2454 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2455   [previously, this check worked only if the rewrite rule was unconditional]
  2456   Now rew can involve either definitions or equalities (either == or =).
  2457 
  2458 
  2459 *** ZF ***
  2460 
  2461 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2462   only the theorems proved on ZF.ML;
  2463 
  2464 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2465   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2466   disjointness reasoning but breaking a few old proofs.
  2467 
  2468 * ZF/Update: new theory of function updates
  2469     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2470   may also be iterated as in f(a:=b,c:=d,...);
  2471 
  2472 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2473 
  2474 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2475   [previously, this check worked only if the rewrite rule was unconditional]
  2476   Now rew can involve either definitions or equalities (either == or =).
  2477 
  2478 * case_tac provided for compatibility with HOL
  2479     (like the old excluded_middle_tac, but with subgoals swapped)
  2480 
  2481 
  2482 *** Internal programming interfaces ***
  2483 
  2484 * Pure: several new basic modules made available for general use, see
  2485 also src/Pure/README;
  2486 
  2487 * improved the theory data mechanism to support encapsulation (data
  2488 kind name replaced by private Object.kind, acting as authorization
  2489 key); new type-safe user interface via functor TheoryDataFun; generic
  2490 print_data function becomes basically useless;
  2491 
  2492 * removed global_names compatibility flag -- all theory declarations
  2493 are qualified by default;
  2494 
  2495 * module Pure/Syntax now offers quote / antiquote translation
  2496 functions (useful for Hoare logic etc. with implicit dependencies);
  2497 see HOL/ex/Antiquote for an example use;
  2498 
  2499 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2500 cterm -> thm;
  2501 
  2502 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2503 subgoal;
  2504 
  2505 * Display.print_goals function moved to Locale.print_goals;
  2506 
  2507 * standard print function for goals supports current_goals_markers
  2508 variable for marking begin of proof, end of proof, start of goal; the
  2509 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2510 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2511 for example;
  2512 
  2513 
  2514 
  2515 New in Isabelle98 (January 1998)
  2516 --------------------------------
  2517 
  2518 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2519 
  2520 * changed lexical syntax of terms / types: dots made part of long
  2521 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2522 
  2523 * simpset (and claset) reference variable replaced by functions
  2524 simpset / simpset_ref;
  2525 
  2526 * no longer supports theory aliases (via merge) and non-trivial
  2527 implicit merge of thms' signatures;
  2528 
  2529 * most internal names of constants changed due to qualified names;
  2530 
  2531 * changed Pure/Sequence interface (see Pure/seq.ML);
  2532 
  2533 
  2534 *** General Changes ***
  2535 
  2536 * hierachically structured name spaces (for consts, types, axms, thms
  2537 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2538 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2539 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2540 long_names for fully qualified output names; NOTE: ML programs
  2541 (special tactics, packages etc.) referring to internal names may have
  2542 to be adapted to cope with fully qualified names; in case of severe
  2543 backward campatibility problems try setting 'global_names' at compile
  2544 time to have enrything declared within a flat name space; one may also
  2545 fine tune name declarations in theories via the 'global' and 'local'
  2546 section;
  2547 
  2548 * reimplemented the implicit simpset and claset using the new anytype
  2549 data filed in signatures; references simpset:simpset ref etc. are
  2550 replaced by functions simpset:unit->simpset and
  2551 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2552 to patch your ML files accordingly;
  2553 
  2554 * HTML output now includes theory graph data for display with Java
  2555 applet or isatool browser; data generated automatically via isatool
  2556 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2557 
  2558 * defs may now be conditional; improved rewrite_goals_tac to handle
  2559 conditional equations;
  2560 
  2561 * defs now admits additional type arguments, using TYPE('a) syntax;
  2562 
  2563 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2564 creates a new theory node; implicit merge of thms' signatures is
  2565 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2566 transfer:theory->thm->thm in (rare) cases;
  2567 
  2568 * improved handling of draft signatures / theories; draft thms (and
  2569 ctyps, cterms) are automatically promoted to real ones;
  2570 
  2571 * slightly changed interfaces for oracles: admit many per theory, named
  2572 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2573 
  2574 * print_goals: optional output of const types (set show_consts and
  2575 show_types);
  2576 
  2577 * improved output of warnings (###) and errors (***);
  2578 
  2579 * subgoal_tac displays a warning if the new subgoal has type variables;
  2580 
  2581 * removed old README and Makefiles;
  2582 
  2583 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2584 
  2585 * removed obsolete init_pps and init_database;
  2586 
  2587 * deleted the obsolete tactical STATE, which was declared by
  2588     fun STATE tacfun st = tacfun st st;
  2589 
  2590 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2591 (which abbreviates $HOME);
  2592 
  2593 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2594 use isatool fixseq to adapt your ML programs (this works for fully
  2595 qualified references to the Sequence structure only!);
  2596 
  2597 * use_thy no longer requires writable current directory; it always
  2598 reloads .ML *and* .thy file, if either one is out of date;
  2599 
  2600 
  2601 *** Classical Reasoner ***
  2602 
  2603 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2604 tactics that use classical reasoning to simplify a subgoal without
  2605 splitting it into several subgoals;
  2606 
  2607 * Safe_tac: like safe_tac but uses the default claset;
  2608 
  2609 
  2610 *** Simplifier ***
  2611 
  2612 * added simplification meta rules:
  2613     (asm_)(full_)simplify: simpset -> thm -> thm;
  2614 
  2615 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2616 logics (again);
  2617 
  2618 * added prems argument to simplification procedures;
  2619 
  2620 * HOL, FOL, ZF: added infix function `addsplits':
  2621   instead of `<simpset> setloop (split_tac <thms>)'
  2622   you can simply write `<simpset> addsplits <thms>'
  2623 
  2624 
  2625 *** Syntax ***
  2626 
  2627 * TYPE('a) syntax for type reflection terms;
  2628 
  2629 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2630 
  2631 * pretty printer: changed order of mixfix annotation preference (again!);
  2632 
  2633 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2634 
  2635 
  2636 *** HOL ***
  2637 
  2638 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2639   with `addloop' of the simplifier to faciliate case splitting in premises.
  2640 
  2641 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2642 
  2643 * HOL/Auth: new protocol proofs including some for the Internet
  2644   protocol TLS;
  2645 
  2646 * HOL/Map: new theory of `maps' a la VDM;
  2647 
  2648 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2649 cancelling out common nat summands from =, <, <= (in)equalities, or
  2650 differences; simplification procedures nat_cancel_factor for
  2651 cancelling common factor from =, <, <= (in)equalities over natural
  2652 sums; nat_cancel contains both kinds of procedures, it is installed by
  2653 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2654 
  2655 * HOL/simplifier: terms of the form
  2656   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2657   are rewritten to
  2658   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2659   and those of the form
  2660   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2661   are rewritten to
  2662   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2663 
  2664 * HOL/datatype
  2665   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2666 
  2667   P(t_case f1 ... fn x) =
  2668      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2669         ...
  2670        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2671      )
  2672 
  2673   and a theorem `split_t_case_asm' of the form
  2674 
  2675   P(t_case f1 ... fn x) =
  2676     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2677         ...
  2678        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2679      )
  2680   which can be added to a simpset via `addsplits'. The existing theorems
  2681   expand_list_case and expand_option_case have been renamed to
  2682   split_list_case and split_option_case.
  2683 
  2684 * HOL/Arithmetic:
  2685   - `pred n' is automatically converted to `n-1'.
  2686     Users are strongly encouraged not to use `pred' any longer,
  2687     because it will disappear altogether at some point.
  2688   - Users are strongly encouraged to write "0 < n" rather than
  2689     "n ~= 0". Theorems and proof tools have been modified towards this
  2690     `standard'.
  2691 
  2692 * HOL/Lists:
  2693   the function "set_of_list" has been renamed "set" (and its theorems too);
  2694   the function "nth" now takes its arguments in the reverse order and
  2695   has acquired the infix notation "!" as in "xs!n".
  2696 
  2697 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2698 
  2699 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2700   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2701 
  2702 * HOL/record: extensible records with schematic structural subtyping
  2703 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2704 still lacks various theorems and concrete record syntax;
  2705 
  2706 
  2707 *** HOLCF ***
  2708 
  2709 * removed "axioms" and "generated by" sections;
  2710 
  2711 * replaced "ops" section by extended "consts" section, which is capable of
  2712   handling the continuous function space "->" directly;
  2713 
  2714 * domain package:
  2715   . proves theorems immediately and stores them in the theory,
  2716   . creates hierachical name space,
  2717   . now uses normal mixfix annotations (instead of cinfix...),
  2718   . minor changes to some names and values (for consistency),
  2719   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2720   . separator between mutual domain defs: changed "," to "and",
  2721   . improved handling of sort constraints;  now they have to
  2722     appear on the left-hand side of the equations only;
  2723 
  2724 * fixed LAM <x,y,zs>.b syntax;
  2725 
  2726 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2727 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2728 
  2729 
  2730 *** FOL and ZF ***
  2731 
  2732 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2733   with `addloop' of the simplifier to faciliate case splitting in premises.
  2734 
  2735 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2736 in HOL, they strip ALL and --> from proved theorems;
  2737 
  2738 
  2739 
  2740 New in Isabelle94-8 (May 1997)
  2741 ------------------------------
  2742 
  2743 *** General Changes ***
  2744 
  2745 * new utilities to build / run / maintain Isabelle etc. (in parts
  2746 still somewhat experimental); old Makefiles etc. still functional;
  2747 
  2748 * new 'Isabelle System Manual';
  2749 
  2750 * INSTALL text, together with ./configure and ./build scripts;
  2751 
  2752 * reimplemented type inference for greater efficiency, better error
  2753 messages and clean internal interface;
  2754 
  2755 * prlim command for dealing with lots of subgoals (an easier way of
  2756 setting goals_limit);
  2757 
  2758 
  2759 *** Syntax ***
  2760 
  2761 * supports alternative (named) syntax tables (parser and pretty
  2762 printer); internal interface is provided by add_modesyntax(_i);
  2763 
  2764 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2765 be used in conjunction with the Isabelle symbol font; uses the
  2766 "symbols" syntax table;
  2767 
  2768 * added token_translation interface (may translate name tokens in
  2769 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2770 the current print_mode); IMPORTANT: user print translation functions
  2771 are responsible for marking newly introduced bounds
  2772 (Syntax.mark_boundT);
  2773 
  2774 * token translations for modes "xterm" and "xterm_color" that display
  2775 names in bold, underline etc. or colors (which requires a color
  2776 version of xterm);
  2777 
  2778 * infixes may now be declared with names independent of their syntax;
  2779 
  2780 * added typed_print_translation (like print_translation, but may
  2781 access type of constant);
  2782 
  2783 
  2784 *** Classical Reasoner ***
  2785 
  2786 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2787 some limitations.  Blast_tac...
  2788   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2789   + ignores elimination rules that don't have the correct format
  2790         (the conclusion MUST be a formula variable)
  2791   + ignores types, which can make HOL proofs fail
  2792   + rules must not require higher-order unification, e.g. apply_type in ZF
  2793     [message "Function Var's argument not a bound variable" relates to this]
  2794   + its proof strategy is more general but can actually be slower
  2795 
  2796 * substitution with equality assumptions no longer permutes other
  2797 assumptions;
  2798 
  2799 * minor changes in semantics of addafter (now called addaltern); renamed
  2800 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2801 (and access functions for it);
  2802 
  2803 * improved combination of classical reasoner and simplifier:
  2804   + functions for handling clasimpsets
  2805   + improvement of addss: now the simplifier is called _after_ the
  2806     safe steps.
  2807   + safe variant of addss called addSss: uses safe simplifications
  2808     _during_ the safe steps. It is more complete as it allows multiple
  2809     instantiations of unknowns (e.g. with slow_tac).
  2810 
  2811 *** Simplifier ***
  2812 
  2813 * added interface for simplification procedures (functions that
  2814 produce *proven* rewrite rules on the fly, depending on current
  2815 redex);
  2816 
  2817 * ordering on terms as parameter (used for ordered rewriting);
  2818 
  2819 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2820 
  2821 * the solver is now split into a safe and an unsafe part.
  2822 This should be invisible for the normal user, except that the
  2823 functions setsolver and addsolver have been renamed to setSolver and
  2824 addSolver; added safe_asm_full_simp_tac;
  2825 
  2826 
  2827 *** HOL ***
  2828 
  2829 * a generic induction tactic `induct_tac' which works for all datatypes and
  2830 also for type `nat';
  2831 
  2832 * a generic case distinction tactic `exhaust_tac' which works for all
  2833 datatypes and also for type `nat';
  2834 
  2835 * each datatype comes with a function `size';
  2836 
  2837 * patterns in case expressions allow tuple patterns as arguments to
  2838 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2839 
  2840 * primrec now also works with type nat;
  2841 
  2842 * recdef: a new declaration form, allows general recursive functions to be
  2843 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2844 
  2845 * the constant for negation has been renamed from "not" to "Not" to
  2846 harmonize with FOL, ZF, LK, etc.;
  2847 
  2848 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2849 infinite lists;
  2850 
  2851 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2852 
  2853 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2854 problems in commutative rings, using axiomatic type classes for + and *;
  2855 
  2856 * more examples in HOL/MiniML and HOL/Auth;
  2857 
  2858 * more default rewrite rules for quantifiers, union/intersection;
  2859 
  2860 * a new constant `arbitrary == @x.False';
  2861 
  2862 * HOLCF/IOA replaces old HOL/IOA;
  2863 
  2864 * HOLCF changes: derived all rules and arities
  2865   + axiomatic type classes instead of classes
  2866   + typedef instead of faking type definitions
  2867   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2868   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2869   + eliminated the types void, one, tr
  2870   + use unit lift and bool lift (with translations) instead of one and tr
  2871   + eliminated blift from Lift3.thy (use Def instead of blift)
  2872   all eliminated rules are derived as theorems --> no visible changes ;
  2873 
  2874 
  2875 *** ZF ***
  2876 
  2877 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2878 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2879 as ZF_cs addSIs [equalityI];
  2880 
  2881 
  2882 
  2883 New in Isabelle94-7 (November 96)
  2884 ---------------------------------
  2885 
  2886 * allowing negative levels (as offsets) in prlev and choplev;
  2887 
  2888 * super-linear speedup for large simplifications;
  2889 
  2890 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2891 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2892 FAIL); can suppress it using the command Delsimps (ex_simps @
  2893 all_simps); De Morgan laws are also now included, by default;
  2894 
  2895 * improved printing of ==>  :  ~:
  2896 
  2897 * new object-logic "Sequents" adds linear logic, while replacing LK
  2898 and Modal (thanks to Sara Kalvala);
  2899 
  2900 * HOL/Auth: correctness proofs for authentication protocols;
  2901 
  2902 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2903 examples on HOL/Auth);
  2904 
  2905 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2906 the rewriter and classical reasoner simultaneously;
  2907 
  2908 * function uresult no longer returns theorems in "standard" format;
  2909 regain previous version by: val uresult = standard o uresult;
  2910 
  2911 
  2912 
  2913 New in Isabelle94-6
  2914 -------------------
  2915 
  2916 * oracles -- these establish an interface between Isabelle and trusted
  2917 external reasoners, which may deliver results as theorems;
  2918 
  2919 * proof objects (in particular record all uses of oracles);
  2920 
  2921 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2922 
  2923 * "constdefs" section in theory files;
  2924 
  2925 * "primrec" section (HOL) no longer requires names;
  2926 
  2927 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2928 
  2929 
  2930 
  2931 New in Isabelle94-5
  2932 -------------------
  2933 
  2934 * reduced space requirements;
  2935 
  2936 * automatic HTML generation from theories;
  2937 
  2938 * theory files no longer require "..." (quotes) around most types;
  2939 
  2940 * new examples, including two proofs of the Church-Rosser theorem;
  2941 
  2942 * non-curried (1994) version of HOL is no longer distributed;
  2943 
  2944 
  2945 
  2946 New in Isabelle94-4
  2947 -------------------
  2948 
  2949 * greatly reduced space requirements;
  2950 
  2951 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2952 
  2953 * searchable theorem database (see the section "Retrieving theorems" on
  2954 page 8 of the Reference Manual);
  2955 
  2956 * new examples, including Grabczewski's monumental case study of the
  2957 Axiom of Choice;
  2958 
  2959 * The previous version of HOL renamed to Old_HOL;
  2960 
  2961 * The new version of HOL (previously called CHOL) uses a curried syntax
  2962 for functions.  Application looks like f a b instead of f(a,b);
  2963 
  2964 * Mutually recursive inductive definitions finally work in HOL;
  2965 
  2966 * In ZF, pattern-matching on tuples is now available in all abstractions and
  2967 translates to the operator "split";
  2968 
  2969 
  2970 
  2971 New in Isabelle94-3
  2972 -------------------
  2973 
  2974 * new infix operator, addss, allowing the classical reasoner to
  2975 perform simplification at each step of its search.  Example:
  2976         fast_tac (cs addss ss)
  2977 
  2978 * a new logic, CHOL, the same as HOL, but with a curried syntax
  2979 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  2980 look like (a,b) instead of <a,b>;
  2981 
  2982 * PLEASE NOTE: CHOL will eventually replace HOL!
  2983 
  2984 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  2985 It translates to the operator "split".  A new theory of integers is available;
  2986 
  2987 * In ZF, integer numerals now denote two's-complement binary integers.
  2988 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  2989 
  2990 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  2991 of the Axiom of Choice;
  2992 
  2993 
  2994 
  2995 New in Isabelle94-2
  2996 -------------------
  2997 
  2998 * Significantly faster resolution;
  2999 
  3000 * the different sections in a .thy file can now be mixed and repeated
  3001 freely;
  3002 
  3003 * Database of theorems for FOL, HOL and ZF.  New
  3004 commands including qed, qed_goal and bind_thm store theorems in the database.
  3005 
  3006 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3007 a given theory (thms_of), or find out what theory a theorem was proved in
  3008 (theory_of_thm);
  3009 
  3010 * Bugs fixed in the inductive definition and datatype packages;
  3011 
  3012 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3013 and HOL_dup_cs obsolete;
  3014 
  3015 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3016 have been removed;
  3017 
  3018 * Simpler definition of function space in ZF;
  3019 
  3020 * new results about cardinal and ordinal arithmetic in ZF;
  3021 
  3022 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3023 types;
  3024 
  3025 
  3026 $Id$