NEWS
author wenzelm
Tue May 31 11:53:42 2005 +0200 (2005-05-31)
changeset 16151 cf7f146086bc
parent 16112 27585e65028b
child 16168 adb83939177f
permissions -rw-r--r--
ML Pure: name spaces have been refined;
ML Pure: cases produced by proof methods specify options, NONE means to removee bindings;
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryn>
    13   begin
    14 
    15   optionally also with a "files" section. The syntax
    16 
    17   theory <name> = <theory1> + ... + <theoryn>:
    18 
    19   will still be supported for some time but will eventually disappear.
    20   The syntax of old-style theories has not changed.
    21 
    22 * Theory loader: parent theories can now also be referred to via
    23   relative and absolute paths.
    24 
    25 * Provers/quasi.ML: new transitivity reasoners for transitivity only
    26   and quasi orders.
    27 
    28 * Provers/trancl.ML: new transitivity reasoner for transitive and
    29   reflexive-transitive closure of relations.
    30 
    31 * Provers/blast.ML: new reference depth_limit to make blast's depth
    32   limit (previously hard-coded with a value of 20) user-definable.
    33 
    34 * Provers: new version of the subst method, for single-step rewriting: it now
    35   works in bound variable contexts. New is subst (asm), for rewriting an
    36   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    37   subterm than the original subst method, which is still available under the
    38   name simplesubst.
    39 
    40 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    41   More generally, erule now works even if the major premise of the elimination rule
    42   contains !! or ==>.
    43 
    44 * Pure: considerably improved version of 'constdefs' command.  Now
    45   performs automatic type-inference of declared constants; additional
    46   support for local structure declarations (cf. locales and HOL
    47   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    48   to observe strictly sequential dependencies of definitions within a
    49   single 'constdefs' section; moreover, the declared name needs to be
    50   an identifier.  If all fails, consider to fall back on 'consts' and
    51   'defs' separately.
    52 
    53 * Pure: improved indexed syntax and implicit structures.  First of
    54   all, indexed syntax provides a notational device for subscripted
    55   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    56   expressions.  Secondly, in a local context with structure
    57   declarations, number indexes \<^sub>n or the empty index (default
    58   number 1) refer to a certain fixed variable implicitly; option
    59   show_structs controls printing of implicit structures.  Typical
    60   applications of these concepts involve record types and locales.
    61 
    62 * Pure: clear separation of logical types and nonterminals, where the
    63   latter may only occur in 'syntax' specifications or type
    64   abbreviations.  Before that distinction was only partially
    65   implemented via type class "logic" vs. "{}".  Potential
    66   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    67   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    68   specifications may require further adaption (e.g. Cube/Base.thy).
    69 
    70 * Pure: removed obsolete type class "logic", use the top sort {}
    71   instead.  Note that non-logical types should be declared as
    72   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    73   object-logic specifications.
    74 
    75 * Pure: command 'no_syntax' removes grammar declarations (and
    76   translations) resulting from the given syntax specification, which
    77   is interpreted in the same manner as for the 'syntax' command.
    78 
    79 * Pure: print_tac now outputs the goal through the trace channel.
    80 
    81 * Pure: reference NameSpace.unique_names included.  If true the
    82   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    83   yet). If false the first entry wins (as during parsing). Default
    84   value is true.
    85 
    86 * Pure: tuned internal renaming of symbolic identifiers -- attach
    87   primes instead of base 26 numbers.
    88 
    89 * Pure: new flag show_question_marks controls printing of leading
    90   question marks in schematic variable names.
    91 
    92 * Pure: new version of thms_containing that searches for a list of
    93   criteria instead of a list of constants. Known criteria are: intro,
    94   elim, dest, name:string, simp:term, and any term. Criteria can be 
    95   preceded by '-' to select theorems that do not match. Intro, elim, 
    96   dest select theorems that match the current goal, name:s selects
    97   theorems whose fully qualified name contain s, and simp:term selects
    98   all simplification rules whose lhs match term.  Any other term is 
    99   interpreted as pattern and selects all theorems matching the
   100   pattern. Available in ProofGeneral under 'ProofGeneral -> Find
   101   Theorems' or C-c C-f.
   102 
   103   Example: C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
   104 
   105   prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   106   matching the current goal as introduction rule and not having "HOL." 
   107   in their name (i.e. not being defined in theory HOL).
   108 
   109 * Pure/Syntax: In schematic variable names, *any* symbol following
   110   \<^isub> or \<^isup> is now treated as part of the base name.  For
   111   example, the following works without printing of ugly ".0" indexes:
   112 
   113     lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   114       by simp
   115 
   116 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   117 
   118 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   119   specified in mixfix annotations as "(00...)".
   120 
   121 * Pure/Syntax: 'advanced' translation functions (parse_translation
   122   etc.) may depend on the signature of the theory context being
   123   presently used for parsing/printing, see also isar-ref manual.
   124 
   125 * Pure/Simplifier: you can control the depth to which conditional rewriting
   126   is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth Limit.
   127 
   128 * Pure/Simplifier: simplification procedures may now take the current
   129   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   130   interface), which is very useful for calling the Simplifier
   131   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   132   simprocs is gone -- use prems_of_ss on the simpset instead.
   133   Moreover, the low-level mk_simproc no longer applies Logic.varify
   134   internally, to allow for use in a context of fixed variables.
   135 
   136 * Isar debugging: new reference Toplevel.debug; default false.  Set to
   137   make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   138   
   139 * Locales: modifications regarding "includes"
   140   - "includes" disallowed in declaration of named locales (command "locale").
   141   - Fixed parameter management in theorem generation for goals with "includes".
   142     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   143 
   144 * Locales: locale expressions permit optional mixfix redeclaration for
   145   renamed parameters.
   146 
   147 * Locales: new commands for the interpretation of locale expressions
   148   in theories (interpretation) and proof contexts (interpret).  These take an
   149   instantiation of the locale parameters and compute proof obligations from
   150   the instantiated specification.  After the obligations have been discharged,
   151   the instantiated theorems of the locale are added to the theory or proof
   152   context.  Interpretation is smart in that already active interpretations
   153   do not occur in proof obligations, neither are instantiated theorems stored
   154   in duplicate.
   155   Use print_interps to inspect active interpretations of a particular locale.
   156   For details, see the Isar Reference manual.
   157 
   158 * Locales: proper static binding of attribute syntax -- i.e. types /
   159   terms / facts mentioned as arguments are always those of the locale
   160   definition context, independently of the context of later
   161   invocations.  Moreover, locale operations (renaming and type / term
   162   instantiation) are applied to attribute arguments as expected.
   163 
   164   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   165   of actual attributes; rare situations may require Attrib.attribute
   166   to embed those attributes into Attrib.src that lack concrete syntax.
   167 
   168   Attribute implementations need to cooperate properly with the static
   169   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   170   Attrib.XXX_thm etc. already do the right thing without further
   171   intervention.  Only unusual applications -- such as "where" or "of"
   172   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   173   both on the context and the facts involved -- may have to assign
   174   parsed values to argument tokens explicitly.
   175 
   176 * Attributes 'induct' and 'cases': type or set names may now be
   177   locally fixed variables as well.
   178 
   179 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   180   selections of theorems in named facts via indices.
   181 
   182 * Pure: reorganized bootstrapping of the Pure theories; CPure is now
   183   derived from Pure, which contains all common declarations already.
   184   Both theories are defined via plain Isabelle/Isar .thy files.
   185   INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   186   CPure.elim / CPure.dest attributes) now appear in the Pure name
   187   space; use isatool fixcpure to adapt your theory and ML sources.
   188 
   189 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   190   is peformed already.  Object-logics merely need to finish their
   191   initial simpset configuration as before.
   192 
   193 
   194 *** Document preparation ***
   195 
   196 * Several new antiquotation:
   197 
   198   @{term_type term} prints a term with its type annotated;
   199 
   200   @{typeof term} prints the type of a term;
   201 
   202   @{const const} is the same as @{term const}, but checks
   203     that the argument is a known logical constant;
   204 
   205   @{term_style style term} and @{thm_style style thm} print a term or
   206     theorem applying a "style" to it
   207 
   208   Predefined styles are "lhs" and "rhs" printing the lhs/rhs of
   209   definitions, equations, inequations etc. and "conclusion" printing
   210   only the conclusion of a meta-logical statement theorem.  Styles may
   211   be defined via TermStyle.add_style in ML.  See the "LaTeX Sugar"
   212   document for more information.
   213 
   214 * Antiquotations now provide the option 'locale=NAME' to specify an
   215   alternative context used for evaluating and printing the subsequent
   216   argument, as in @{thm [locale=LC] fold_commute}, for example.
   217 
   218 * Commands 'display_drafts' and 'print_drafts' perform simple output
   219   of raw sources.  Only those symbols that do not require additional
   220   LaTeX packages (depending on comments in isabellesym.sty) are
   221   displayed properly, everything else is left verbatim.  We use
   222   isatool display and isatool print as front ends; these are subject
   223   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   224 
   225 * Proof scripts as well as some other commands such as ML or
   226   parse/print_translation can now be hidden in the document.  Hiding
   227   is enabled by default, and can be disabled either via the option '-H
   228   false' of isatool usedir or by resetting the reference variable
   229   IsarOutput.hide_commands. Additional commands to be hidden may be
   230   declared using IsarOutput.add_hidden_commands.
   231 
   232 
   233 *** HOL ***
   234 
   235 * Datatype induction via method `induct' now preserves the name of the
   236   induction variable. For example, when proving P(xs::'a list) by induction
   237   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   238   P(list) ==> P(a#list) as previously.
   239 
   240 * HOL/record: reimplementation of records. Improved scalability for
   241   records with many fields, avoiding performance problems for type
   242   inference. Records are no longer composed of nested field types, but
   243   of nested extension types. Therefore the record type only grows
   244   linear in the number of extensions and not in the number of fields.
   245   The top-level (users) view on records is preserved.  Potential
   246   INCOMPATIBILITY only in strange cases, where the theory depends on
   247   the old record representation. The type generated for a record is
   248   called <record_name>_ext_type.
   249 
   250 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   251   enabled to skip the proofs triggered by a record definition or a
   252   simproc (if quick_and_dirty is enabled). Definitions of large
   253   records can take quite long.
   254 
   255 * HOL/record: "record_upd_simproc" for simplification of multiple
   256   record updates enabled by default.  Moreover, trivial updates are
   257   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   258   occasionally, since simplification is more powerful by default.
   259 
   260 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   261 
   262   syntax (epsilon)
   263     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   264 
   265   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   266   and x-symbol; use option '-m epsilon' to get it actually printed.
   267   Moreover, the mathematically important symbolic identifier
   268   \<epsilon> becomes available as variable, constant etc.
   269 
   270 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   271   Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   272   is \<ge>.
   273 
   274 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}" (and similarly for
   275   "\<in>" instead of ":").
   276 
   277 * HOL/SetInterval: The syntax for open intervals has changed:
   278 
   279   Old         New
   280   {..n(}   -> {..<n}
   281   {)n..}   -> {n<..}
   282   {m..n(}  -> {m..<n}
   283   {)m..n}  -> {m<..n}
   284   {)m..n(} -> {m<..<n}
   285 
   286   The old syntax is still supported but will disappear in the future.
   287   For conversion use the following emacs search and replace patterns:
   288 
   289   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   290   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   291 
   292   They are not perfect but work quite well.
   293 
   294 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   295 
   296   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   297   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   298 
   299   There is new syntax for summation over finite sets:
   300 
   301   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   302   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   303   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   304   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   305 
   306   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   307   now translates into 'setsum' as above.
   308 
   309 * HOL: Finite set induction: In Isar proofs, the insert case is now
   310   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   311 
   312 * HOL/Simplifier:
   313 
   314   - Is now set up to reason about transitivity chains involving "trancl"
   315   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   316   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   317   occasionally as simplification may now solve more goals than previously.
   318 
   319   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   320   all partial orders (class "order"), in particular numbers and sets. For
   321   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   322 
   323   - Simproc for "let x = a in f x"
   324   If a is a free or bound variable or a constant then the let is unfolded.
   325   Otherwise first a is simplified to a', and then f a' is simplified to
   326   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   327   otherwise we unfold the let and arrive at g. The simproc can be 
   328   enabled/disabled by the reference use_let_simproc. Potential
   329   INCOMPATIBILITY since simplification is more powerful by default.
   330 
   331 * HOL: The 'refute' command has been extended to support a much larger
   332   fragment of HOL, including axiomatic type classes, constdefs and typedefs,
   333   inductive datatypes and recursion.
   334 
   335 
   336 *** HOLCF ***
   337 
   338 * HOLCF: discontinued special version of 'constdefs' (which used to
   339   support continuous functions) in favor of the general Pure one with
   340   full type-inference.
   341 
   342 
   343 *** ZF ***
   344 
   345 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   346   First Isomorphism Theorem (on quotienting by the kernel of a
   347   homomorphism).
   348 
   349 * ZF/Simplifier: install second copy of type solver that actually
   350   makes use of TC rules declared to Isar proof contexts (or locales);
   351   the old version is still required for ML proof scripts.
   352 
   353 
   354 *** System ***
   355 
   356 * Allow symlinks to all proper Isabelle executables (Isabelle,
   357   isabelle, isatool etc.).
   358 
   359 * isabelle-process: Poly/ML no longer needs Perl to run an interactive
   360   session.
   361 
   362 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   363   isatool doc, isatool mkdir, display_drafts etc.).
   364 
   365 * isatool usedir: option -f allows specification of the ML file to be
   366   used by Isabelle; default is ROOT.ML.
   367 
   368 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   369   (containing Boolean satisfiability problems) into Isabelle/HOL
   370   theories.
   371 
   372 
   373 *** ML ***
   374 
   375 * Pure/library.ML no longer defines its own option datatype, but uses
   376   that of the SML basis, which has constructors NONE and SOME instead
   377   of None and Some, as well as exception Option.Option instead of
   378   OPTION.  The functions the, if_none, is_some, is_none have been
   379   adapted accordingly, while Option.map replaces apsome.
   380 
   381 * The exception LIST has been given up in favour of the standard
   382   exceptions Empty and Subscript, as well as Library.UnequalLengths.
   383   Function like Library.hd and Library.tl are superceded by the
   384   standard hd and tl functions etc.
   385 
   386   A number of basic functions are now no longer exported to the ML
   387   toplevel, as they are variants of standard functions.  The following
   388   suggests how one can translate existing code:
   389 
   390     rev_append xs ys = List.revAppend (xs, ys)
   391     nth_elem (i, xs) = List.nth (xs, i)
   392     last_elem xs = List.last xs
   393     flat xss = List.concat xss
   394     seq fs = app fs
   395     partition P xs = List.partition P xs
   396     filter P xs = List.filter P xs
   397     mapfilter f xs = List.mapPartial f xs
   398 
   399 * Pure: output via the Isabelle channels of writeln/warning/error
   400   etc. is now passed through Output.output, with a hook for arbitrary
   401   transformations depending on the print_mode (cf. Output.add_mode --
   402   the first active mode that provides a output function wins).
   403   Already formatted output may be embedded into further text via
   404   Output.raw; the result of Pretty.string_of/str_of and derived
   405   functions (string_of_term/cterm/thm etc.) is already marked raw to
   406   accommodate easy composition of diagnostic messages etc.
   407   Programmers rarely need to care about Output.output or Output.raw at
   408   all, with some notable exceptions: Output.output is required when
   409   bypassing the standard channels (writeln etc.), or in token
   410   translations to produce properly formatted results; Output.raw is
   411   required when capturing already output material that will eventually
   412   be presented to the user a second time.  For the default print mode,
   413   both Output.output and Output.raw have no effect.
   414 
   415 * Pure: name spaces have been refined, with significant changes of the
   416   internal interfaces -- INCOMPATIBILITY.  Renamed cond_extern(_table)
   417   to extern(_table).  The plain name entry path is superceded by a
   418   general 'naming' context, which also includes the 'policy' to
   419   produce a fully qualified name and external accesses of a fully
   420   qualified name; NameSpace.extend is superceded by context dependent
   421   Sign.declare_name.  Several theory and proof context operations
   422   modify the naming context; especially note Theory.restore_naming and
   423   ProofContext.restore_naming.
   424 
   425 * Pure: cases produced by proof methods specify options, where NONE
   426   means to remove case bindings -- INCOMPATIBILITY in
   427   (RAW_)METHOD_CASES.
   428 
   429 * Provers: Simplifier and Classical Reasoner now support proof context
   430   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   431   components are stored in the theory and patched into the
   432   simpset/claset when used in an Isar proof context.  Context
   433   dependent components are maintained by the following theory
   434   operations:
   435 
   436     Simplifier.add_context_simprocs
   437     Simplifier.del_context_simprocs
   438     Simplifier.set_context_subgoaler
   439     Simplifier.reset_context_subgoaler
   440     Simplifier.add_context_looper
   441     Simplifier.del_context_looper
   442     Simplifier.add_context_unsafe_solver
   443     Simplifier.add_context_safe_solver
   444 
   445     Classical.add_context_safe_wrapper
   446     Classical.del_context_safe_wrapper
   447     Classical.add_context_unsafe_wrapper
   448     Classical.del_context_unsafe_wrapper
   449 
   450   IMPORTANT NOTE: proof tools (methods etc.) need to use
   451   local_simpset_of and local_claset_of to instead of the primitive
   452   Simplifier.get_local_simpset and Classical.get_local_claset,
   453   respectively, in order to see the context dependent fields!
   454 
   455 
   456 
   457 New in Isabelle2004 (April 2004)
   458 --------------------------------
   459 
   460 *** General ***
   461 
   462 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   463   Replaces linorder.ML.
   464 
   465 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   466   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   467   (\<a>...\<z>), are now considered normal letters, and can therefore
   468   be used anywhere where an ASCII letter (a...zA...Z) has until
   469   now. COMPATIBILITY: This obviously changes the parsing of some
   470   terms, especially where a symbol has been used as a binder, say
   471   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   472   as an identifier.  Fix it by inserting a space around former
   473   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   474   existing theory and ML files.
   475 
   476 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   477 
   478 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   479   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   480   a normal (but invisible) letter. For multiple letter subscripts repeat
   481   \<^isub> like this: x\<^isub>1\<^isub>2.
   482 
   483 * Pure: There are now sub-/superscripts that can span more than one
   484   character. Text between \<^bsub> and \<^esub> is set in subscript in
   485   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   486   superscript. The new control characters are not identifier parts.
   487 
   488 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   489   content of "..." to the latex file instead of \isacntrl... . The "..."
   490   may consist of any printable characters excluding the end bracket >.
   491 
   492 * Pure: Using new Isar command "finalconsts" (or the ML functions
   493   Theory.add_finals or Theory.add_finals_i) it is now possible to
   494   declare constants "final", which prevents their being given a definition
   495   later.  It is useful for constants whose behaviour is fixed axiomatically
   496   rather than definitionally, such as the meta-logic connectives.
   497 
   498 * Pure: 'instance' now handles general arities with general sorts
   499   (i.e. intersections of classes),
   500 
   501 * Presentation: generated HTML now uses a CSS style sheet to make layout
   502   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   503   It can be changed to alter the colors/layout of generated pages.
   504 
   505 
   506 *** Isar ***
   507 
   508 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   509   cut_tac, subgoal_tac and thin_tac:
   510   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   511     locales are no longer forced to write Isar proof scripts.
   512     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   513     emulations.
   514   - INCOMPATIBILITY: names of variables to be instantiated may no
   515     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   516     This is consistent with the instantiation attribute "where".
   517 
   518 * Attributes "where" and "of":
   519   - Now take type variables of instantiated theorem into account when reading
   520     the instantiation string.  This fixes a bug that caused instantiated
   521     theorems to have too special types in some circumstances.
   522   - "where" permits explicit instantiations of type variables.
   523 
   524 * Calculation commands "moreover" and "also" no longer interfere with
   525   current facts ("this"), admitting arbitrary combinations with "then"
   526   and derived forms.
   527 
   528 * Locales:
   529   - Goal statements involving the context element "includes" no longer
   530     generate theorems with internal delta predicates (those ending on
   531     "_axioms") in the premise.
   532     Resolve particular premise with <locale>.intro to obtain old form.
   533   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   534     specification and "includes" elements in goal statement.
   535   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   536     [intro?] and [elim?] (respectively) by default.
   537   - Experimental command for instantiation of locales in proof contexts:
   538         instantiate <label>[<attrs>]: <loc>
   539     Instantiates locale <loc> and adds all its theorems to the current context
   540     taking into account their attributes.  Label and attrs are optional
   541     modifiers, like in theorem declarations.  If present, names of
   542     instantiated theorems are qualified with <label>, and the attributes
   543     <attrs> are applied after any attributes these theorems might have already.
   544       If the locale has assumptions, a chained fact of the form
   545     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   546     are derived.  The command does not support old-style locales declared
   547     with "locale (open)".
   548       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   549 
   550 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   551   (Isar) contexts.
   552 
   553 
   554 *** HOL ***
   555 
   556 * Proof import: new image HOL4 contains the imported library from
   557   the HOL4 system with about 2500 theorems. It is imported by
   558   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   559   can be used like any other Isabelle image.  See
   560   HOL/Import/HOL/README for more information.
   561 
   562 * Simplifier:
   563   - Much improved handling of linear and partial orders.
   564     Reasoners for linear and partial orders are set up for type classes
   565     "linorder" and "order" respectively, and are added to the default simpset
   566     as solvers.  This means that the simplifier can build transitivity chains
   567     to solve goals from the assumptions.
   568   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   569     of blast or auto after simplification become unnecessary because the goal
   570     is solved by simplification already.
   571 
   572 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   573     all proved in axiomatic type classes for semirings, rings and fields.
   574 
   575 * Numerics:
   576   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   577     now formalized using the Ring_and_Field theory mentioned above.
   578   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   579     than before, because now they are set up once in a generic manner.
   580   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   581     Look for the general versions in Ring_and_Field (and Power if they concern
   582     exponentiation).
   583 
   584 * Type "rat" of the rational numbers is now available in HOL-Complex.
   585 
   586 * Records:
   587   - Record types are now by default printed with their type abbreviation
   588     instead of the list of all field types. This can be configured via
   589     the reference "print_record_type_abbr".
   590   - Simproc "record_upd_simproc" for simplification of multiple updates added
   591     (not enabled by default).
   592   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   593     EX x. x = sel r to True (not enabled by default).
   594   - Tactic "record_split_simp_tac" to split and simplify records added.
   595 
   596 * 'specification' command added, allowing for definition by
   597   specification.  There is also an 'ax_specification' command that
   598   introduces the new constants axiomatically.
   599 
   600 * arith(_tac) is now able to generate counterexamples for reals as well.
   601 
   602 * HOL-Algebra: new locale "ring" for non-commutative rings.
   603 
   604 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   605   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   606 
   607 * HOL-Matrix: a first theory for matrices in HOL with an application of
   608   matrix theory to linear programming.
   609 
   610 * Unions and Intersections:
   611   The latex output syntax of UN and INT has been changed
   612   from "\Union x \in A. B" to "\Union_{x \in A} B"
   613   i.e. the index formulae has become a subscript.
   614   Similarly for "\Union x. B", and for \Inter instead of \Union.
   615 
   616 * Unions and Intersections over Intervals:
   617   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   618   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   619   like in normal math, and corresponding versions for < and for intersection.
   620 
   621 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   622   lexicographic dictonary ordering has been added as "lexord".
   623 
   624 * ML: the legacy theory structures Int and List have been removed. They had
   625   conflicted with ML Basis Library structures having the same names.
   626 
   627 * 'refute' command added to search for (finite) countermodels.  Only works
   628   for a fragment of HOL.  The installation of an external SAT solver is
   629   highly recommended.  See "HOL/Refute.thy" for details.
   630 
   631 * 'quickcheck' command: Allows to find counterexamples by evaluating
   632   formulae under an assignment of free variables to random values.
   633   In contrast to 'refute', it can deal with inductive datatypes,
   634   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   635   for examples.
   636 
   637 
   638 *** HOLCF ***
   639 
   640 * Streams now come with concatenation and are part of the HOLCF image
   641 
   642 
   643 
   644 New in Isabelle2003 (May 2003)
   645 ------------------------------
   646 
   647 *** General ***
   648 
   649 * Provers/simplifier:
   650 
   651   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   652     Assumptions are now subject to complete mutual simplification,
   653     not just from left to right. The simplifier now preserves
   654     the order of assumptions.
   655 
   656     Potential INCOMPATIBILITY:
   657 
   658     -- simp sometimes diverges where the old version did
   659        not, e.g. invoking simp on the goal
   660 
   661         [| P (f x); y = x; f x = f y |] ==> Q
   662 
   663        now gives rise to the infinite reduction sequence
   664 
   665         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   666 
   667        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   668        kind of problem.
   669 
   670     -- Tactics combining classical reasoner and simplification (such as auto)
   671        are also affected by this change, because many of them rely on
   672        simp. They may sometimes diverge as well or yield a different numbers
   673        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   674        in case of problems. Sometimes subsequent calls to the classical
   675        reasoner will fail because a preceeding call to the simplifier too
   676        eagerly simplified the goal, e.g. deleted redundant premises.
   677 
   678   - The simplifier trace now shows the names of the applied rewrite rules
   679 
   680   - You can limit the number of recursive invocations of the simplifier
   681     during conditional rewriting (where the simplifie tries to solve the
   682     conditions before applying the rewrite rule):
   683     ML "simp_depth_limit := n"
   684     where n is an integer. Thus you can force termination where previously
   685     the simplifier would diverge.
   686 
   687   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   688 
   689   - No longer aborts on failed congruence proof.  Instead, the
   690     congruence is ignored.
   691 
   692 * Pure: New generic framework for extracting programs from constructive
   693   proofs. See HOL/Extraction.thy for an example instantiation, as well
   694   as HOL/Extraction for some case studies.
   695 
   696 * Pure: The main goal of the proof state is no longer shown by default, only
   697 the subgoals. This behaviour is controlled by a new flag.
   698    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   699 (ML: Proof.show_main_goal).
   700 
   701 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   702 rules whose conclusion matches subgoal 1:
   703       PG menu: Isabelle/Isar -> Show me -> matching rules
   704 The rules are ordered by how closely they match the subgoal.
   705 In particular, rules that solve a subgoal outright are displayed first
   706 (or rather last, the way they are printed).
   707 (ML: ProofGeneral.print_intros())
   708 
   709 * Pure: New flag trace_unify_fail causes unification to print
   710 diagnostic information (PG: in trace buffer) when it fails. This is
   711 useful for figuring out why single step proofs like rule, erule or
   712 assumption failed.
   713 
   714 * Pure: Locale specifications now produce predicate definitions
   715 according to the body of text (covering assumptions modulo local
   716 definitions); predicate "loc_axioms" covers newly introduced text,
   717 while "loc" is cumulative wrt. all included locale expressions; the
   718 latter view is presented only on export into the global theory
   719 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   720 on the old view without predicates;
   721 
   722 * Pure: predefined locales "var" and "struct" are useful for sharing
   723 parameters (as in CASL, for example); just specify something like
   724 ``var x + var y + struct M'' as import;
   725 
   726 * Pure: improved thms_containing: proper indexing of facts instead of
   727 raw theorems; check validity of results wrt. current name space;
   728 include local facts of proof configuration (also covers active
   729 locales), cover fixed variables in index; may use "_" in term
   730 specification; an optional limit for the number of printed facts may
   731 be given (the default is 40);
   732 
   733 * Pure: disallow duplicate fact bindings within new-style theory files
   734 (batch-mode only);
   735 
   736 * Provers: improved induct method: assumptions introduced by case
   737 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   738 the goal statement); "foo" still refers to all facts collectively;
   739 
   740 * Provers: the function blast.overloaded has been removed: all constants
   741 are regarded as potentially overloaded, which improves robustness in exchange
   742 for slight decrease in efficiency;
   743 
   744 * Provers/linorder: New generic prover for transitivity reasoning over
   745 linear orders.  Note: this prover is not efficient!
   746 
   747 * Isar: preview of problems to finish 'show' now produce an error
   748 rather than just a warning (in interactive mode);
   749 
   750 
   751 *** HOL ***
   752 
   753 * arith(_tac)
   754 
   755  - Produces a counter example if it cannot prove a goal.
   756    Note that the counter example may be spurious if the goal is not a formula
   757    of quantifier-free linear arithmetic.
   758    In ProofGeneral the counter example appears in the trace buffer.
   759 
   760  - Knows about div k and mod k where k is a numeral of type nat or int.
   761 
   762  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   763    linear arithmetic fails. This takes account of quantifiers and divisibility.
   764    Presburger arithmetic can also be called explicitly via presburger(_tac).
   765 
   766 * simp's arithmetic capabilities have been enhanced a bit: it now
   767 takes ~= in premises into account (by performing a case split);
   768 
   769 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   770 are distributed over a sum of terms;
   771 
   772 * New tactic "trans_tac" and method "trans" instantiate
   773 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   774 "<=", "<" and "=").
   775 
   776 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   777 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   778 
   779 * 'typedef' command has new option "open" to suppress the set
   780 definition;
   781 
   782 * functions Min and Max on finite sets have been introduced (theory
   783 Finite_Set);
   784 
   785 * attribute [symmetric] now works for relations as well; it turns
   786 (x,y) : R^-1 into (y,x) : R, and vice versa;
   787 
   788 * induct over a !!-quantified statement (say !!x1..xn):
   789   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   790 
   791 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   792 %x. None. Warning: empty_def now refers to the previously hidden definition
   793 of the empty set.
   794 
   795 * Algebra: formalization of classical algebra.  Intended as base for
   796 any algebraic development in Isabelle.  Currently covers group theory
   797 (up to Sylow's theorem) and ring theory (Universal Property of
   798 Univariate Polynomials).  Contributions welcome;
   799 
   800 * GroupTheory: deleted, since its material has been moved to Algebra;
   801 
   802 * Complex: new directory of the complex numbers with numeric constants,
   803 nonstandard complex numbers, and some complex analysis, standard and
   804 nonstandard (Jacques Fleuriot);
   805 
   806 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   807 
   808 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   809 Fleuriot);
   810 
   811 * Real/HahnBanach: updated and adapted to locales;
   812 
   813 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   814 Gray and Kramer);
   815 
   816 * UNITY: added the Meier-Sanders theory of progress sets;
   817 
   818 * MicroJava: bytecode verifier and lightweight bytecode verifier
   819 as abstract algorithms, instantiated to the JVM;
   820 
   821 * Bali: Java source language formalization. Type system, operational
   822 semantics, axiomatic semantics. Supported language features:
   823 classes, interfaces, objects,virtual methods, static methods,
   824 static/instance fields, arrays, access modifiers, definite
   825 assignment, exceptions.
   826 
   827 
   828 *** ZF ***
   829 
   830 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   831 universe, etc.);
   832 
   833 * Main ZF: virtually all theories converted to new-style format;
   834 
   835 
   836 *** ML ***
   837 
   838 * Pure: Tactic.prove provides sane interface for internal proofs;
   839 omits the infamous "standard" operation, so this is more appropriate
   840 than prove_goalw_cterm in many situations (e.g. in simprocs);
   841 
   842 * Pure: improved error reporting of simprocs;
   843 
   844 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   845 up simprocs;
   846 
   847 
   848 *** Document preparation ***
   849 
   850 * uses \par instead of \\ for line breaks in theory text. This may
   851 shift some page breaks in large documents. To get the old behaviour
   852 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   853 
   854 * minimized dependencies of isabelle.sty and isabellesym.sty on
   855 other packages
   856 
   857 * \<euro> now needs package babel/greek instead of marvosym (which
   858 broke \Rightarrow)
   859 
   860 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   861 textcomp package)
   862 
   863 
   864 
   865 New in Isabelle2002 (March 2002)
   866 --------------------------------
   867 
   868 *** Document preparation ***
   869 
   870 * greatly simplified document preparation setup, including more
   871 graceful interpretation of isatool usedir -i/-d/-D options, and more
   872 instructive isatool mkdir; users should basically be able to get
   873 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   874 users may run a separate document processing stage manually like this:
   875 "isatool usedir -D output HOL Test && isatool document Test/output";
   876 
   877 * theory dependency graph may now be incorporated into documents;
   878 isatool usedir -g true will produce session_graph.eps/.pdf for use
   879 with \includegraphics of LaTeX;
   880 
   881 * proper spacing of consecutive markup elements, especially text
   882 blocks after section headings;
   883 
   884 * support bold style (for single symbols only), input syntax is like
   885 this: "\<^bold>\<alpha>" or "\<^bold>A";
   886 
   887 * \<bullet> is now output as bold \cdot by default, which looks much
   888 better in printed text;
   889 
   890 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   891 note that these symbols are currently unavailable in Proof General /
   892 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   893 
   894 * isatool latex no longer depends on changed TEXINPUTS, instead
   895 isatool document copies the Isabelle style files to the target
   896 location;
   897 
   898 
   899 *** Isar ***
   900 
   901 * Pure/Provers: improved proof by cases and induction;
   902   - 'case' command admits impromptu naming of parameters (such as
   903     "case (Suc n)");
   904   - 'induct' method divinates rule instantiation from the inductive
   905     claim; no longer requires excessive ?P bindings for proper
   906     instantiation of cases;
   907   - 'induct' method properly enumerates all possibilities of set/type
   908     rules; as a consequence facts may be also passed through *type*
   909     rules without further ado;
   910   - 'induct' method now derives symbolic cases from the *rulified*
   911     rule (before it used to rulify cases stemming from the internal
   912     atomized version); this means that the context of a non-atomic
   913     statement becomes is included in the hypothesis, avoiding the
   914     slightly cumbersome show "PROP ?case" form;
   915   - 'induct' may now use elim-style induction rules without chaining
   916     facts, using ``missing'' premises from the goal state; this allows
   917     rules stemming from inductive sets to be applied in unstructured
   918     scripts, while still benefitting from proper handling of non-atomic
   919     statements; NB: major inductive premises need to be put first, all
   920     the rest of the goal is passed through the induction;
   921   - 'induct' proper support for mutual induction involving non-atomic
   922     rule statements (uses the new concept of simultaneous goals, see
   923     below);
   924   - append all possible rule selections, but only use the first
   925     success (no backtracking);
   926   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   927   - undeclared rule case names default to numbers 1, 2, 3, ...;
   928   - added 'print_induct_rules' (covered by help item in recent Proof
   929     General versions);
   930   - moved induct/cases attributes to Pure, methods to Provers;
   931   - generic method setup instantiated for FOL and HOL;
   932 
   933 * Pure: support multiple simultaneous goal statements, for example
   934 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   935 meta-level mechanism, this acts as if several individual goals had
   936 been stated separately; in particular common proof methods need to be
   937 repeated in order to cover all claims; note that a single elimination
   938 step is *not* sufficient to establish the two conjunctions, so this
   939 fails:
   940 
   941   assume "A & B" then have A and B ..   (*".." fails*)
   942 
   943 better use "obtain" in situations as above; alternative refer to
   944 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   945 
   946 * Pure: proper integration with ``locales''; unlike the original
   947 version by Florian Kammller, Isar locales package high-level proof
   948 contexts rather than raw logical ones (e.g. we admit to include
   949 attributes everywhere); operations on locales include merge and
   950 rename; support for implicit arguments (``structures''); simultaneous
   951 type-inference over imports and text; see also HOL/ex/Locales.thy for
   952 some examples;
   953 
   954 * Pure: the following commands have been ``localized'', supporting a
   955 target locale specification "(in name)": 'lemma', 'theorem',
   956 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   957 stored both within the locale and at the theory level (exported and
   958 qualified by the locale name);
   959 
   960 * Pure: theory goals may now be specified in ``long'' form, with
   961 ad-hoc contexts consisting of arbitrary locale elements. for example
   962 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   963 definitions may be given, too); the result is a meta-level rule with
   964 the context elements being discharged in the obvious way;
   965 
   966 * Pure: new proof command 'using' allows to augment currently used
   967 facts after a goal statement ('using' is syntactically analogous to
   968 'apply', but acts on the goal's facts only); this allows chained facts
   969 to be separated into parts given before and after a claim, as in
   970 ``from a and b have C using d and e <proof>'';
   971 
   972 * Pure: renamed "antecedent" case to "rule_context";
   973 
   974 * Pure: new 'judgment' command records explicit information about the
   975 object-logic embedding (used by several tools internally); no longer
   976 use hard-wired "Trueprop";
   977 
   978 * Pure: added 'corollary' command;
   979 
   980 * Pure: fixed 'token_translation' command;
   981 
   982 * Pure: removed obsolete 'exported' attribute;
   983 
   984 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   985 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   986 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   987 
   988 * Pure: method 'atomize' presents local goal premises as object-level
   989 statements (atomic meta-level propositions); setup controlled via
   990 rewrite rules declarations of 'atomize' attribute; example
   991 application: 'induct' method with proper rule statements in improper
   992 proof *scripts*;
   993 
   994 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   995 now consider the syntactic context of assumptions, giving a better
   996 chance to get type-inference of the arguments right (this is
   997 especially important for locales);
   998 
   999 * Pure: "sorry" no longer requires quick_and_dirty in interactive
  1000 mode;
  1001 
  1002 * Pure/obtain: the formal conclusion "thesis", being marked as
  1003 ``internal'', may no longer be reference directly in the text;
  1004 potential INCOMPATIBILITY, may need to use "?thesis" in rare
  1005 situations;
  1006 
  1007 * Pure: generic 'sym' attribute which declares a rule both as pure
  1008 'elim?' and for the 'symmetric' operation;
  1009 
  1010 * Pure: marginal comments ``--'' may now occur just anywhere in the
  1011 text; the fixed correlation with particular command syntax has been
  1012 discontinued;
  1013 
  1014 * Pure: new method 'rules' is particularly well-suited for proof
  1015 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1016 but often produces more compact proof terms with less detours;
  1017 
  1018 * Pure/Provers/classical: simplified integration with pure rule
  1019 attributes and methods; the classical "intro?/elim?/dest?"
  1020 declarations coincide with the pure ones; the "rule" method no longer
  1021 includes classically swapped intros; "intro" and "elim" methods no
  1022 longer pick rules from the context; also got rid of ML declarations
  1023 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1024 INCOMPATIBILITY;
  1025 
  1026 * Provers/classical: attribute 'swapped' produces classical inversions
  1027 of introduction rules;
  1028 
  1029 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1030 rules instead of full simplifier context; 'iff' attribute handles
  1031 conditional rules;
  1032 
  1033 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1034 
  1035 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1036 "(permissive)" option to recover old behavior;
  1037 
  1038 * HOL: 'inductive' no longer features separate (collective) attributes
  1039 for 'intros' (was found too confusing);
  1040 
  1041 * HOL: properly declared induction rules less_induct and
  1042 wf_induct_rule;
  1043 
  1044 
  1045 *** HOL ***
  1046 
  1047 * HOL: moved over to sane numeral syntax; the new policy is as
  1048 follows:
  1049 
  1050   - 0 and 1 are polymorphic constants, which are defined on any
  1051   numeric type (nat, int, real etc.);
  1052 
  1053   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1054   binary representation internally;
  1055 
  1056   - type nat has special constructor Suc, and generally prefers Suc 0
  1057   over 1::nat and Suc (Suc 0) over 2::nat;
  1058 
  1059 This change may cause significant problems of INCOMPATIBILITY; here
  1060 are some hints on converting existing sources:
  1061 
  1062   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1063   entities, so expressions involving "-" (unary or binary minus) need
  1064   to be spaced properly;
  1065 
  1066   - existing occurrences of "1" may need to be constraint "1::nat" or
  1067   even replaced by Suc 0; similar for old "2";
  1068 
  1069   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1070 
  1071   - remove all special provisions on numerals in proofs;
  1072 
  1073 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1074 representation (depends on bin_arith_simps in the default context);
  1075 
  1076 * HOL: symbolic syntax for x^2 (numeral 2);
  1077 
  1078 * HOL: the class of all HOL types is now called "type" rather than
  1079 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1080 in axclass/classes, instance/arities, and (usually rare) occurrences
  1081 in typings (of consts etc.); internally the class is called
  1082 "HOL.type", ML programs should refer to HOLogic.typeS;
  1083 
  1084 * HOL/record package improvements:
  1085   - new derived operations "fields" to build a partial record section,
  1086     "extend" to promote a fixed record to a record scheme, and
  1087     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1088     declared as simp by default;
  1089   - shared operations ("more", "fields", etc.) now need to be always
  1090     qualified) --- potential INCOMPATIBILITY;
  1091   - removed "make_scheme" operations (use "make" with "extend") --
  1092     INCOMPATIBILITY;
  1093   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1094   - provides cases/induct rules for use with corresponding Isar
  1095     methods (for concrete records, record schemes, concrete more
  1096     parts, and schematic more parts -- in that order);
  1097   - internal definitions directly based on a light-weight abstract
  1098     theory of product types over typedef rather than datatype;
  1099 
  1100 * HOL: generic code generator for generating executable ML code from
  1101 specifications; specific support for HOL constructs such as inductive
  1102 datatypes and sets, as well as recursive functions; can be invoked
  1103 via 'generate_code' theory section;
  1104 
  1105 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1106 
  1107 * HOL: consolidated and renamed several theories.  In particular:
  1108         Ord.thy has been absorbed into HOL.thy
  1109         String.thy has been absorbed into List.thy
  1110 
  1111 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1112 (beware of argument permutation!);
  1113 
  1114 * HOL: linorder_less_split superseded by linorder_cases;
  1115 
  1116 * HOL/List: "nodups" renamed to "distinct";
  1117 
  1118 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1119 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1120   - Ex_def has changed, now need to use some_eq_ex
  1121 
  1122 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1123 in this (rare) case use:
  1124 
  1125   delSWrapper "split_all_tac"
  1126   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1127 
  1128 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1129 MAY FAIL;
  1130 
  1131 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1132 Isabelle's type classes, ^ on functions and relations has too general
  1133 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1134 necessary to attach explicit type constraints;
  1135 
  1136 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1137 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1138 renamed accordingly (eg "compI" -> "rel_compI").
  1139 
  1140 * HOL: syntax translations now work properly with numerals and records
  1141 expressions;
  1142 
  1143 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1144 of "lam" -- INCOMPATIBILITY;
  1145 
  1146 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1147 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1148 renamed "Product_Type.unit";
  1149 
  1150 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1151 
  1152 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1153 the "cases" method);
  1154 
  1155 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1156 Florian Kammller);
  1157 
  1158 * HOL/IMP: updated and converted to new-style theory format; several
  1159 parts turned into readable document, with proper Isar proof texts and
  1160 some explanations (by Gerwin Klein);
  1161 
  1162 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1163 
  1164 * HOL-Hyperreal is now a logic image;
  1165 
  1166 
  1167 *** HOLCF ***
  1168 
  1169 * Isar: consts/constdefs supports mixfix syntax for continuous
  1170 operations;
  1171 
  1172 * Isar: domain package adapted to new-style theory format, e.g. see
  1173 HOLCF/ex/Dnat.thy;
  1174 
  1175 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1176 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1177 lift.induct_tac, always use UU instead of Undef;
  1178 
  1179 * HOLCF/IMP: updated and converted to new-style theory;
  1180 
  1181 
  1182 *** ZF ***
  1183 
  1184 * Isar: proper integration of logic-specific tools and packages,
  1185 including theory commands '(co)inductive', '(co)datatype',
  1186 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1187 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1188 
  1189 * theory Main no longer includes AC; for the Axiom of Choice, base
  1190 your theory on Main_ZFC;
  1191 
  1192 * the integer library now covers quotients and remainders, with many
  1193 laws relating division to addition, multiplication, etc.;
  1194 
  1195 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1196 typeless version of the formalism;
  1197 
  1198 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1199 format;
  1200 
  1201 * ZF/Induct: new directory for examples of inductive definitions,
  1202 including theory Multiset for multiset orderings; converted to
  1203 new-style theory format;
  1204 
  1205 * ZF: many new theorems about lists, ordinals, etc.;
  1206 
  1207 
  1208 *** General ***
  1209 
  1210 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1211 variable proof controls level of detail: 0 = no proofs (only oracle
  1212 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1213 also ref manual for further ML interfaces;
  1214 
  1215 * Pure/axclass: removed obsolete ML interface
  1216 goal_subclass/goal_arity;
  1217 
  1218 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1219 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1220 separate tokens, so expressions involving minus need to be spaced
  1221 properly;
  1222 
  1223 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1224 rather than "infixl" or "infixr";
  1225 
  1226 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1227 sort constraint specifications in type inference; e.g. "x::_::foo"
  1228 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1229 type variable);
  1230 
  1231 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1232 control output of nested => (types); the default behavior is
  1233 "type_brackets";
  1234 
  1235 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1236 tokens into AST constants;
  1237 
  1238 * Pure/syntax: prefer later declarations of translations and print
  1239 translation functions; potential INCOMPATIBILITY: need to reverse
  1240 multiple declarations for same syntax element constant;
  1241 
  1242 * Pure/show_hyps reset by default (in accordance to existing Isar
  1243 practice);
  1244 
  1245 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1246 addSafter;
  1247 
  1248 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1249 as well;
  1250 
  1251 * system: tested support for MacOS X; should be able to get Isabelle +
  1252 Proof General to work in a plain Terminal after installing Poly/ML
  1253 (e.g. from the Isabelle distribution area) and GNU bash alone
  1254 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1255 support requires further installations, e.g. from
  1256 http://fink.sourceforge.net/);
  1257 
  1258 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1259 
  1260 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1261 of 40 MB), cf. ML_OPTIONS;
  1262 
  1263 * system: Proof General keywords specification is now part of the
  1264 Isabelle distribution (see etc/isar-keywords.el);
  1265 
  1266 * system: support for persistent Proof General sessions (refrain from
  1267 outdating all loaded theories on startup); user may create writable
  1268 logic images like this: ``isabelle -q HOL Test'';
  1269 
  1270 * system: smart selection of Isabelle process versus Isabelle
  1271 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1272 run both "isabelle" and "Isabelle" even if file names are badly
  1273 damaged (executable inspects the case of the first letter of its own
  1274 name); added separate "isabelle-process" and "isabelle-interface";
  1275 
  1276 * system: refrain from any attempt at filtering input streams; no
  1277 longer support ``8bit'' encoding of old isabelle font, instead proper
  1278 iso-latin characters may now be used; the related isatools
  1279 "symbolinput" and "nonascii" have disappeared as well;
  1280 
  1281 * system: removed old "xterm" interface (the print modes "xterm" and
  1282 "xterm_color" are still available for direct use in a suitable
  1283 terminal);
  1284 
  1285 
  1286 
  1287 New in Isabelle99-2 (February 2001)
  1288 -----------------------------------
  1289 
  1290 *** Overview of INCOMPATIBILITIES ***
  1291 
  1292 * HOL: please note that theories in the Library and elsewhere often use the
  1293 new-style (Isar) format; to refer to their theorems in an ML script you must
  1294 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1295 
  1296 * HOL: inductive package no longer splits induction rule aggressively,
  1297 but only as far as specified by the introductions given; the old
  1298 format may be recovered via ML function complete_split_rule or attribute
  1299 'split_rule (complete)';
  1300 
  1301 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1302 gfp_Tarski to gfp_unfold;
  1303 
  1304 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1305 
  1306 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1307 relation); infix "^^" has been renamed "``"; infix "``" has been
  1308 renamed "`"; "univalent" has been renamed "single_valued";
  1309 
  1310 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1311 operation;
  1312 
  1313 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1314 
  1315 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1316 
  1317 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1318 consequence, it is no longer monotonic wrt. the local goal context
  1319 (which is now passed through the inductive cases);
  1320 
  1321 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1322 \<gg> to \<ggreater>;
  1323 
  1324 
  1325 *** Document preparation ***
  1326 
  1327 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1328 available: are "it" for near math-mode best-style output, "sl" for
  1329 slanted text style, and "tt" for plain type-writer; if no
  1330 \isabellestyle command is given, output is according to slanted
  1331 type-writer);
  1332 
  1333 * support sub/super scripts (for single symbols only), input syntax is
  1334 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1335 
  1336 * some more standard symbols; see Appendix A of the system manual for
  1337 the complete list of symbols defined in isabellesym.sty;
  1338 
  1339 * improved isabelle style files; more abstract symbol implementation
  1340 (should now use \isamath{...} and \isatext{...} in custom symbol
  1341 definitions);
  1342 
  1343 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1344 state; Note that presentation of goal states does not conform to
  1345 actual human-readable proof documents.  Please do not include goal
  1346 states into document output unless you really know what you are doing!
  1347 
  1348 * proper indentation of antiquoted output with proportional LaTeX
  1349 fonts;
  1350 
  1351 * no_document ML operator temporarily disables LaTeX document
  1352 generation;
  1353 
  1354 * isatool unsymbolize tunes sources for plain ASCII communication;
  1355 
  1356 
  1357 *** Isar ***
  1358 
  1359 * Pure: Isar now suffers initial goal statements to contain unbound
  1360 schematic variables (this does not conform to actual readable proof
  1361 documents, due to unpredictable outcome and non-compositional proof
  1362 checking); users who know what they are doing may use schematic goals
  1363 for Prolog-style synthesis of proven results;
  1364 
  1365 * Pure: assumption method (an implicit finishing) now handles actual
  1366 rules as well;
  1367 
  1368 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1369 initial goal, declare "that" only as Pure intro (only for single
  1370 steps); the "that" rule assumption may now be involved in implicit
  1371 finishing, thus ".." becomes a feasible for trivial obtains;
  1372 
  1373 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1374 instance proofs may be performed by "..";
  1375 
  1376 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1377 statements as well;
  1378 
  1379 * Pure: more robust selection of calculational rules;
  1380 
  1381 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1382 rule (as well as the assumption rule);
  1383 
  1384 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1385 lemmas, using the graph browser tool;
  1386 
  1387 * Pure: predict failure of "show" in interactive mode;
  1388 
  1389 * Pure: 'thms_containing' now takes actual terms as arguments;
  1390 
  1391 * HOL: improved method 'induct' --- now handles non-atomic goals
  1392 (potential INCOMPATIBILITY); tuned error handling;
  1393 
  1394 * HOL: cases and induct rules now provide explicit hints about the
  1395 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1396 any remaining facts are inserted into the goal verbatim;
  1397 
  1398 * HOL: local contexts (aka cases) may now contain term bindings as
  1399 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1400 the result to be shown in each case;
  1401 
  1402 * HOL: added 'recdef_tc' command;
  1403 
  1404 * isatool convert assists in eliminating legacy ML scripts;
  1405 
  1406 
  1407 *** HOL ***
  1408 
  1409 * HOL/Library: a collection of generic theories to be used together
  1410 with main HOL; the theory loader path already includes this directory
  1411 by default; the following existing theories have been moved here:
  1412 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1413 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1414 
  1415 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1416 modelling and verification task performed in Isabelle/HOL +
  1417 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1418 
  1419 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1420 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1421 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1422 'domain', this makes the theory consistent with mathematical
  1423 literature;
  1424 
  1425 * HOL basics: added overloaded operations "inverse" and "divide"
  1426 (infix "/"), syntax for generic "abs" operation, generic summation
  1427 operator \<Sum>;
  1428 
  1429 * HOL/typedef: simplified package, provide more useful rules (see also
  1430 HOL/subset.thy);
  1431 
  1432 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1433 now expressed as a proper nested rule (old-style tactic scripts may
  1434 require atomize_strip_tac to cope with non-atomic premises);
  1435 
  1436 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1437 to "split_conv" (old name still available for compatibility);
  1438 
  1439 * HOL: improved concrete syntax for strings (e.g. allows translation
  1440 rules with string literals);
  1441 
  1442 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1443  and Fleuriot's mechanization of analysis, including the transcendental
  1444  functions for the reals;
  1445 
  1446 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1447 
  1448 
  1449 *** CTT ***
  1450 
  1451 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1452 "lam" is displayed as TWO lambda-symbols
  1453 
  1454 * CTT: theory Main now available, containing everything (that is, Bool
  1455 and Arith);
  1456 
  1457 
  1458 *** General ***
  1459 
  1460 * Pure: the Simplifier has been implemented properly as a derived rule
  1461 outside of the actual kernel (at last!); the overall performance
  1462 penalty in practical applications is about 50%, while reliability of
  1463 the Isabelle inference kernel has been greatly improved;
  1464 
  1465 * print modes "brackets" and "no_brackets" control output of nested =>
  1466 (types) and ==> (props); the default behaviour is "brackets";
  1467 
  1468 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1469 as assumptions as well;
  1470 
  1471 * system: support Poly/ML 4.0;
  1472 
  1473 * system: isatool install handles KDE version 1 or 2;
  1474 
  1475 
  1476 
  1477 New in Isabelle99-1 (October 2000)
  1478 ----------------------------------
  1479 
  1480 *** Overview of INCOMPATIBILITIES ***
  1481 
  1482 * HOL: simplification of natural numbers is much changed; to partly
  1483 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1484 issue the following ML commands:
  1485 
  1486   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1487   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1488 
  1489 * HOL: simplification no longer dives into case-expressions; this is
  1490 controlled by "t.weak_case_cong" for each datatype t;
  1491 
  1492 * HOL: nat_less_induct renamed to less_induct;
  1493 
  1494 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1495 fixsome to patch .thy and .ML sources automatically;
  1496 
  1497   select_equality  -> some_equality
  1498   select_eq_Ex     -> some_eq_ex
  1499   selectI2EX       -> someI2_ex
  1500   selectI2         -> someI2
  1501   selectI          -> someI
  1502   select1_equality -> some1_equality
  1503   Eps_sym_eq       -> some_sym_eq_trivial
  1504   Eps_eq           -> some_eq_trivial
  1505 
  1506 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1507 
  1508 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1509 instead);
  1510 
  1511 * HOL: the recursion equations generated by 'recdef' are now called
  1512 f.simps instead of f.rules;
  1513 
  1514 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1515 
  1516 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1517 sometimes be needed;
  1518 
  1519 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1520 
  1521 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1522 
  1523 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1524 product is now "<*>" instead of "Times"; the lexicographic product is
  1525 now "<*lex*>" instead of "**";
  1526 
  1527 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1528 of main HOL, but was unused); better use HOL's datatype package;
  1529 
  1530 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1531 the old syntax may be recovered as follows:
  1532 
  1533   syntax (symbols)
  1534     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1535       (infixl "\\<oplus>" 100)
  1536 
  1537 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1538 
  1539 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1540 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1541 internally;
  1542 
  1543 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1544 changed from A/r to A//r;
  1545 
  1546 * ZF: new treatment of arithmetic (nat & int) may break some old
  1547 proofs;
  1548 
  1549 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1550 rulify -> rule_format, elimify -> elim_format, ...);
  1551 
  1552 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1553 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1554 should have to change intro!! to intro? only); replaced "delrule" by
  1555 "rule del";
  1556 
  1557 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1558 
  1559 * Provers: strengthened force_tac by using new first_best_tac;
  1560 
  1561 * LaTeX document preparation: several changes of isabelle.sty (see
  1562 lib/texinputs);
  1563 
  1564 
  1565 *** Document preparation ***
  1566 
  1567 * formal comments (text blocks etc.) in new-style theories may now
  1568 contain antiquotations of thm/prop/term/typ/text to be presented
  1569 according to latex print mode; concrete syntax is like this:
  1570 @{term[show_types] "f(x) = a + x"};
  1571 
  1572 * isatool mkdir provides easy setup of Isabelle session directories,
  1573 including proper document sources;
  1574 
  1575 * generated LaTeX sources are now deleted after successful run
  1576 (isatool document -c); may retain a copy somewhere else via -D option
  1577 of isatool usedir;
  1578 
  1579 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1580 style files, achieving self-contained LaTeX sources and simplifying
  1581 LaTeX debugging;
  1582 
  1583 * old-style theories now produce (crude) LaTeX output as well;
  1584 
  1585 * browser info session directories are now self-contained (may be put
  1586 on WWW server seperately); improved graphs of nested sessions; removed
  1587 graph for 'all sessions';
  1588 
  1589 * several improvements in isabelle style files; \isabellestyle{it}
  1590 produces fake math mode output; \isamarkupheader is now \section by
  1591 default; see lib/texinputs/isabelle.sty etc.;
  1592 
  1593 
  1594 *** Isar ***
  1595 
  1596 * Isar/Pure: local results and corresponding term bindings are now
  1597 subject to Hindley-Milner polymorphism (similar to ML); this
  1598 accommodates incremental type-inference very nicely;
  1599 
  1600 * Isar/Pure: new derived language element 'obtain' supports
  1601 generalized existence reasoning;
  1602 
  1603 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1604 support accumulation of results, without applying any rules yet;
  1605 useful to collect intermediate results without explicit name
  1606 references, and for use with transitivity rules with more than 2
  1607 premises;
  1608 
  1609 * Isar/Pure: scalable support for case-analysis type proofs: new
  1610 'case' language element refers to local contexts symbolically, as
  1611 produced by certain proof methods; internally, case names are attached
  1612 to theorems as "tags";
  1613 
  1614 * Isar/Pure: theory command 'hide' removes declarations from
  1615 class/type/const name spaces;
  1616 
  1617 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1618 indicate potential overloading;
  1619 
  1620 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1621 
  1622 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1623 "{a,b,c}" instead of {a,b,c};
  1624 
  1625 * Isar/Pure now provides its own version of intro/elim/dest
  1626 attributes; useful for building new logics, but beware of confusion
  1627 with the version in Provers/classical;
  1628 
  1629 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1630 case name 'antecedent';
  1631 
  1632 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1633 to the current context is now done automatically);
  1634 
  1635 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1636 for definining proof methods in ML;
  1637 
  1638 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1639 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1640 most cases, one should have to change intro!! to intro? only);
  1641 replaced "delrule" by "rule del";
  1642 
  1643 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1644 'symmetric' attribute (the latter supercedes [RS sym]);
  1645 
  1646 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1647 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1648 well (including splits);
  1649 
  1650 * Isar/Provers: Simplifier and Classical methods now support all kind
  1651 of modifiers used in the past, including 'cong', 'iff', etc.
  1652 
  1653 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1654 of Simplifier and Classical reasoner);
  1655 
  1656 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1657 now support named cases; major packages (inductive, datatype, primrec,
  1658 recdef) support case names and properly name parameters;
  1659 
  1660 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1661 monotonicity conditions are extracted to be proven at end of
  1662 calculations;
  1663 
  1664 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1665 method anyway;
  1666 
  1667 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1668 split_if split_if_asm; datatype package provides theorems foo.splits =
  1669 foo.split foo.split_asm for each datatype;
  1670 
  1671 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1672 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1673 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1674 use "(cases (simplified))" method in proper proof texts);
  1675 
  1676 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1677 
  1678 * Isar: names of theorems etc. may be natural numbers as well;
  1679 
  1680 * Isar: 'pr' command: optional arguments for goals_limit and
  1681 ProofContext.prems_limit; no longer prints theory contexts, but only
  1682 proof states;
  1683 
  1684 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1685 additional print modes to be specified; e.g. "pr(latex)" will print
  1686 proof state according to the Isabelle LaTeX style;
  1687 
  1688 * Isar: improved support for emulating tactic scripts, including proof
  1689 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1690 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1691 (for HOL datatypes);
  1692 
  1693 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1694 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1695 'proof method scripts' have to be in depth-first order;
  1696 
  1697 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1698 
  1699 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1700 should instead use individual commands for printing items
  1701 (print_commands, print_methods etc.);
  1702 
  1703 * Isar: added 'nothing' --- the empty list of theorems;
  1704 
  1705 
  1706 *** HOL ***
  1707 
  1708 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1709 corresponding virtual machine and a specification of its bytecode
  1710 verifier and a lightweight bytecode verifier, including proofs of
  1711 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1712 Cornelia Pusch (see also the homepage of project Bali at
  1713 http://isabelle.in.tum.de/Bali/);
  1714 
  1715 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1716 Clemens Ballarin;
  1717 
  1718 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1719 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1720 Rasmussen;
  1721 
  1722 * HOL/Lattice: fundamental concepts of lattice theory and order
  1723 structures, including duals, properties of bounds versus algebraic
  1724 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1725 Theorem for complete lattices etc.; may also serve as a demonstration
  1726 for abstract algebraic reasoning using axiomatic type classes, and
  1727 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1728 
  1729 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1730 von Oheimb;
  1731 
  1732 * HOL/IMPP: extension of IMP with local variables and mutually
  1733 recursive procedures, by David von Oheimb;
  1734 
  1735 * HOL/Lambda: converted into new-style theory and document;
  1736 
  1737 * HOL/ex/Multiquote: example of multiple nested quotations and
  1738 anti-quotations -- basically a generalized version of de-Bruijn
  1739 representation; very useful in avoiding lifting of operations;
  1740 
  1741 * HOL/record: added general record equality rule to simpset; fixed
  1742 select-update simplification procedure to handle extended records as
  1743 well; admit "r" as field name;
  1744 
  1745 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1746 other numeric types and also as the identity of groups, rings, etc.;
  1747 
  1748 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1749 Types nat and int belong to this axclass;
  1750 
  1751 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1752    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1753    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1754   two terms #m*u and #n*u are replaced by #(m+n)*u
  1755     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1756   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1757     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1758 
  1759 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1760 powerful prover for predicate logic but knows nothing of clasets; see
  1761 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1762 
  1763 * HOL: new version of "case_tac" subsumes both boolean case split and
  1764 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1765 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1766 
  1767 * HOL: simplification no longer dives into case-expressions: only the
  1768 selector expression is simplified, but not the remaining arms; to
  1769 enable full simplification of case-expressions for datatype t, you may
  1770 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1771 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1772 
  1773 * HOL/recdef: the recursion equations generated by 'recdef' for
  1774 function 'f' are now called f.simps instead of f.rules; if all
  1775 termination conditions are proved automatically, these simplification
  1776 rules are added to the simpset, as in primrec; rules may be named
  1777 individually as well, resulting in a separate list of theorems for
  1778 each equation;
  1779 
  1780 * HOL/While is a new theory that provides a while-combinator. It
  1781 permits the definition of tail-recursive functions without the
  1782 provision of a termination measure. The latter is necessary once the
  1783 invariant proof rule for while is applied.
  1784 
  1785 * HOL: new (overloaded) notation for the set of elements below/above
  1786 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1787 
  1788 * HOL: theorems impI, allI, ballI bound as "strip";
  1789 
  1790 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1791 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1792 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1793 
  1794 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1795 
  1796 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1797 main HOL, but was unused);
  1798 
  1799 * HOL: fewer consts declared as global (e.g. have to refer to
  1800 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1801 
  1802 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1803 in case of overlap with user translations (e.g. judgements over
  1804 tuples); (note that the underlying logical represenation is still
  1805 bogus);
  1806 
  1807 
  1808 *** ZF ***
  1809 
  1810 * ZF: simplification automatically cancels common terms in arithmetic
  1811 expressions over nat and int;
  1812 
  1813 * ZF: new treatment of nat to minimize type-checking: all operators
  1814 coerce their operands to a natural number using the function natify,
  1815 making the algebraic laws unconditional;
  1816 
  1817 * ZF: as above, for int: operators coerce their operands to an integer
  1818 using the function intify;
  1819 
  1820 * ZF: the integer library now contains many of the usual laws for the
  1821 orderings, including $<=, and monotonicity laws for $+ and $*;
  1822 
  1823 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1824 simplification;
  1825 
  1826 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1827 to the simplifier and classical reasoner simultaneously;
  1828 
  1829 
  1830 *** General ***
  1831 
  1832 * Provers: blast_tac now handles actual object-logic rules as
  1833 assumptions; note that auto_tac uses blast_tac internally as well;
  1834 
  1835 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1836 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1837 
  1838 * Provers: delrules now handles destruct rules as well (no longer need
  1839 explicit make_elim);
  1840 
  1841 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1842   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1843 use instead the strong form,
  1844   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1845 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1846 from destruct-rules;
  1847 
  1848 * Provers: Simplifier.easy_setup provides a fast path to basic
  1849 Simplifier setup for new object-logics;
  1850 
  1851 * Pure: AST translation rules no longer require constant head on LHS;
  1852 
  1853 * Pure: improved name spaces: ambiguous output is qualified; support
  1854 for hiding of names;
  1855 
  1856 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1857 XSYMBOL_HOME; no longer need to do manual configuration in most
  1858 situations;
  1859 
  1860 * system: compression of ML heaps images may now be controlled via -c
  1861 option of isabelle and isatool usedir (currently only observed by
  1862 Poly/ML);
  1863 
  1864 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1865 useful for remote X11);
  1866 
  1867 * system: provide TAGS file for Isabelle sources;
  1868 
  1869 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1870 order;
  1871 
  1872 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1873 timing flag supersedes proof_timing and Toplevel.trace;
  1874 
  1875 * ML: new combinators |>> and |>>> for incremental transformations
  1876 with secondary results (e.g. certain theory extensions):
  1877 
  1878 * ML: PureThy.add_defs gets additional argument to indicate potential
  1879 overloading (usually false);
  1880 
  1881 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1882 results;
  1883 
  1884 
  1885 
  1886 New in Isabelle99 (October 1999)
  1887 --------------------------------
  1888 
  1889 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1890 
  1891 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1892 are no longer simplified.  (This allows the simplifier to unfold recursive
  1893 functional programs.)  To restore the old behaviour, declare
  1894 
  1895     Delcongs [if_weak_cong];
  1896 
  1897 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1898 complement;
  1899 
  1900 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1901 
  1902 * HOL/datatype: mutual_induct_tac no longer exists --
  1903   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1904 
  1905 * HOL/typedef: fixed type inference for representing set; type
  1906 arguments now have to occur explicitly on the rhs as type constraints;
  1907 
  1908 * ZF: The con_defs part of an inductive definition may no longer refer
  1909 to constants declared in the same theory;
  1910 
  1911 * HOL, ZF: the function mk_cases, generated by the inductive
  1912 definition package, has lost an argument.  To simplify its result, it
  1913 uses the default simpset instead of a supplied list of theorems.
  1914 
  1915 * HOL/List: the constructors of type list are now Nil and Cons;
  1916 
  1917 * Simplifier: the type of the infix ML functions
  1918         setSSolver addSSolver setSolver addSolver
  1919 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1920 for packaging solvers. A solver is created via
  1921         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1922 where the string argument is only a comment.
  1923 
  1924 
  1925 *** Proof tools ***
  1926 
  1927 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1928 decision procedure for linear arithmetic. Currently it is used for
  1929 types `nat', `int', and `real' in HOL (see below); it can, should and
  1930 will be instantiated for other types and logics as well.
  1931 
  1932 * The simplifier now accepts rewrite rules with flexible heads, eg
  1933      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1934   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1935   matching.
  1936 
  1937 
  1938 *** General ***
  1939 
  1940 * New Isabelle/Isar subsystem provides an alternative to traditional
  1941 tactical theorem proving; together with the ProofGeneral/isar user
  1942 interface it offers an interactive environment for developing human
  1943 readable proof documents (Isar == Intelligible semi-automated
  1944 reasoning); for further information see isatool doc isar-ref,
  1945 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1946 
  1947 * improved and simplified presentation of theories: better HTML markup
  1948 (including colors), graph views in several sizes; isatool usedir now
  1949 provides a proper interface for user theories (via -P option); actual
  1950 document preparation based on (PDF)LaTeX is available as well (for
  1951 new-style theories only); see isatool doc system for more information;
  1952 
  1953 * native support for Proof General, both for classic Isabelle and
  1954 Isabelle/Isar;
  1955 
  1956 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1957 using the graph browser tool;
  1958 
  1959 * Isabelle manuals now also available as PDF;
  1960 
  1961 * theory loader rewritten from scratch (may not be fully
  1962 bug-compatible); old loadpath variable has been replaced by show_path,
  1963 add_path, del_path, reset_path functions; new operations such as
  1964 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1965 isatool doc ref);
  1966 
  1967 * improved isatool install: option -k creates KDE application icon,
  1968 option -p DIR installs standalone binaries;
  1969 
  1970 * added ML_PLATFORM setting (useful for cross-platform installations);
  1971 more robust handling of platform specific ML images for SML/NJ;
  1972 
  1973 * the settings environment is now statically scoped, i.e. it is never
  1974 created again in sub-processes invoked from isabelle, isatool, or
  1975 Isabelle;
  1976 
  1977 * path element specification '~~' refers to '$ISABELLE_HOME';
  1978 
  1979 * in locales, the "assumes" and "defines" parts may be omitted if
  1980 empty;
  1981 
  1982 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1983 long arrows);
  1984 
  1985 * new print_mode "HTML";
  1986 
  1987 * new flag show_tags controls display of tags of theorems (which are
  1988 basically just comments that may be attached by some tools);
  1989 
  1990 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1991 mode and goal output format:
  1992 
  1993 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1994 244c244
  1995 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1996 ---
  1997 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1998 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1999 181c181
  2000 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  2001 ---
  2002 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  2003 
  2004 * function bind_thms stores lists of theorems (cf. bind_thm);
  2005 
  2006 * new shorthand tactics ftac, eatac, datac, fatac;
  2007 
  2008 * qed (and friends) now accept "" as result name; in that case the
  2009 theorem is not stored, but proper checks and presentation of the
  2010 result still apply;
  2011 
  2012 * theorem database now also indexes constants "Trueprop", "all",
  2013 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2014 
  2015 
  2016 *** HOL ***
  2017 
  2018 ** HOL arithmetic **
  2019 
  2020 * There are now decision procedures for linear arithmetic over nat and
  2021 int:
  2022 
  2023 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2024 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2025 are treated as atomic; subformulae not involving type `nat' or `int'
  2026 are ignored; quantified subformulae are ignored unless they are
  2027 positive universal or negative existential. The tactic has to be
  2028 invoked by hand and can be a little bit slow. In particular, the
  2029 running time is exponential in the number of occurrences of `min' and
  2030 `max', and `-' on `nat'.
  2031 
  2032 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2033 (negated) (in)equalities among the premises and the conclusion into
  2034 account (i.e. no compound formulae) and does not know about `min' and
  2035 `max', and `-' on `nat'. It is fast and is used automatically by the
  2036 simplifier.
  2037 
  2038 NB: At the moment, these decision procedures do not cope with mixed
  2039 nat/int formulae where the two parts interact, such as `m < n ==>
  2040 int(m) < int(n)'.
  2041 
  2042 * HOL/Numeral provides a generic theory of numerals (encoded
  2043 efficiently as bit strings); setup for types nat/int/real is in place;
  2044 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2045 int, existing theories and proof scripts may require a few additional
  2046 type constraints;
  2047 
  2048 * integer division and remainder can now be performed on constant
  2049 arguments;
  2050 
  2051 * many properties of integer multiplication, division and remainder
  2052 are now available;
  2053 
  2054 * An interface to the Stanford Validity Checker (SVC) is available through the
  2055 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2056 are proved automatically.  SVC must be installed separately, and its results
  2057 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2058 invocation of the underlying oracle).  For SVC see
  2059   http://verify.stanford.edu/SVC
  2060 
  2061 * IsaMakefile: the HOL-Real target now builds an actual image;
  2062 
  2063 
  2064 ** HOL misc **
  2065 
  2066 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2067 (in Isabelle/Isar) -- by Gertrud Bauer;
  2068 
  2069 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2070 analysis for assembly languages with subtypes;
  2071 
  2072 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2073 -- avoids syntactic ambiguities and treats state, transition, and
  2074 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2075 changed syntax and (many) tactics;
  2076 
  2077 * HOL/inductive: Now also handles more general introduction rules such
  2078   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2079   theorems are now maintained within the theory (maintained via the
  2080   "mono" attribute);
  2081 
  2082 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2083   (using function types) such as
  2084 
  2085   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2086 
  2087 * HOL/record: record_simproc (part of the default simpset) takes care
  2088 of selectors applied to updated records; record_split_tac is no longer
  2089 part of the default claset; update_defs may now be removed from the
  2090 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2091 
  2092   claset_ref () := claset() addSWrapper record_split_wrapper;
  2093   Delsimprocs [record_simproc]
  2094 
  2095 * HOL/typedef: fixed type inference for representing set; type
  2096 arguments now have to occur explicitly on the rhs as type constraints;
  2097 
  2098 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2099 names rather than an ML expression;
  2100 
  2101 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2102 supplied later.  Program schemes can be defined, such as
  2103     "While B C s = (if B s then While B C (C s) else s)"
  2104 where the well-founded relation can be chosen after B and C have been given.
  2105 
  2106 * HOL/List: the constructors of type list are now Nil and Cons;
  2107 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2108 course, ML tools referring to List.list.op # etc. have to be adapted;
  2109 
  2110 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2111 disabled by default; run isabelle with option -m HOL to get back to
  2112 the original Gordon/HOL-style output;
  2113 
  2114 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2115 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2116 
  2117 * HOL basic syntax simplified (more orthogonal): all variants of
  2118 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2119 Eps operator is provided as well: "SOME x. P[x]";
  2120 
  2121 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2122 
  2123 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2124 thus available for user theories;
  2125 
  2126 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2127 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2128 time;
  2129 
  2130 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2131 several times and then mp;
  2132 
  2133 
  2134 *** LK ***
  2135 
  2136 * the notation <<...>> is now available as a notation for sequences of
  2137 formulas;
  2138 
  2139 * the simplifier is now installed
  2140 
  2141 * the axiom system has been generalized (thanks to Soren Heilmann)
  2142 
  2143 * the classical reasoner now has a default rule database
  2144 
  2145 
  2146 *** ZF ***
  2147 
  2148 * new primrec section allows primitive recursive functions to be given
  2149 directly (as in HOL) over datatypes and the natural numbers;
  2150 
  2151 * new tactics induct_tac and exhaust_tac for induction (or case
  2152 analysis) over datatypes and the natural numbers;
  2153 
  2154 * the datatype declaration of type T now defines the recursor T_rec;
  2155 
  2156 * simplification automatically does freeness reasoning for datatype
  2157 constructors;
  2158 
  2159 * automatic type-inference, with AddTCs command to insert new
  2160 type-checking rules;
  2161 
  2162 * datatype introduction rules are now added as Safe Introduction rules
  2163 to the claset;
  2164 
  2165 * the syntax "if P then x else y" is now available in addition to
  2166 if(P,x,y);
  2167 
  2168 
  2169 *** Internal programming interfaces ***
  2170 
  2171 * tuned simplifier trace output; new flag debug_simp;
  2172 
  2173 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2174 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2175 
  2176 * AxClass.axclass_tac lost the theory argument;
  2177 
  2178 * tuned current_goals_markers semantics: begin / end goal avoids
  2179 printing empty lines;
  2180 
  2181 * removed prs and prs_fn hook, which was broken because it did not
  2182 include \n in its semantics, forcing writeln to add one
  2183 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2184 string -> unit if you really want to output text without newline;
  2185 
  2186 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2187 plain output, interface builders may have to enable 'isabelle_font'
  2188 mode to get Isabelle font glyphs as before;
  2189 
  2190 * refined token_translation interface; INCOMPATIBILITY: output length
  2191 now of type real instead of int;
  2192 
  2193 * theory loader actions may be traced via new ThyInfo.add_hook
  2194 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2195 your own database of information attached to *whole* theories -- as
  2196 opposed to intra-theory data slots offered via TheoryDataFun;
  2197 
  2198 * proper handling of dangling sort hypotheses (at last!);
  2199 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2200 extra sort hypotheses that can be witnessed from the type signature;
  2201 the force_strip_shyps flag is gone, any remaining shyps are simply
  2202 left in the theorem (with a warning issued by strip_shyps_warning);
  2203 
  2204 
  2205 
  2206 New in Isabelle98-1 (October 1998)
  2207 ----------------------------------
  2208 
  2209 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2210 
  2211 * several changes of automated proof tools;
  2212 
  2213 * HOL: major changes to the inductive and datatype packages, including
  2214 some minor incompatibilities of theory syntax;
  2215 
  2216 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2217 called `inj_on';
  2218 
  2219 * HOL: removed duplicate thms in Arith:
  2220   less_imp_add_less  should be replaced by  trans_less_add1
  2221   le_imp_add_le      should be replaced by  trans_le_add1
  2222 
  2223 * HOL: unary minus is now overloaded (new type constraints may be
  2224 required);
  2225 
  2226 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2227 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2228 now taken as an integer constant.
  2229 
  2230 * Pure: ML function 'theory_of' renamed to 'theory';
  2231 
  2232 
  2233 *** Proof tools ***
  2234 
  2235 * Simplifier:
  2236   1. Asm_full_simp_tac is now more aggressive.
  2237      1. It will sometimes reorient premises if that increases their power to
  2238         simplify.
  2239      2. It does no longer proceed strictly from left to right but may also
  2240         rotate premises to achieve further simplification.
  2241      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2242      old Asm_full_simp_tac in that it does not rotate premises.
  2243   2. The simplifier now knows a little bit about nat-arithmetic.
  2244 
  2245 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2246 allows for selected deletion of wrappers, by introduction of names for
  2247 wrapper functionals.  This implies that addbefore, addSbefore,
  2248 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2249 and that adding two tactics with the same name overwrites the first
  2250 one (emitting a warning).
  2251   type wrapper = (int -> tactic) -> (int -> tactic)
  2252   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2253   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2254   delWrapper, delSWrapper: claset *  string            -> claset
  2255   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2256 
  2257 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2258 semantics; addbefore now affects only the unsafe part of step_tac
  2259 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2260 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2261 by Force_tac;
  2262 
  2263 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2264 compWrapper; added safe wrapper (and access functions for it);
  2265 
  2266 * HOL/split_all_tac is now much faster and fails if there is nothing
  2267 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2268 and the names of the automatically generated variables have changed.
  2269 split_all_tac has moved within claset() from unsafe wrappers to safe
  2270 wrappers, which means that !!-bound variables are split much more
  2271 aggressively, and safe_tac and clarify_tac now split such variables.
  2272 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2273 Note: the same holds for record_split_tac, which does the job of
  2274 split_all_tac for record fields.
  2275 
  2276 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2277 permanently to the default simpset using Addsplits just like
  2278 Addsimps. They can be removed via Delsplits just like
  2279 Delsimps. Lower-case versions are also available.
  2280 
  2281 * HOL/Simplifier: The rule split_if is now part of the default
  2282 simpset. This means that the simplifier will eliminate all occurrences
  2283 of if-then-else in the conclusion of a goal. To prevent this, you can
  2284 either remove split_if completely from the default simpset by
  2285 `Delsplits [split_if]' or remove it in a specific call of the
  2286 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2287 other case splitting rules to/from the default simpset: every datatype
  2288 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2289 t is the name of the datatype).
  2290 
  2291 * Classical reasoner / Simplifier combination: new force_tac (and
  2292 derivatives Force_tac, force) combines rewriting and classical
  2293 reasoning (and whatever other tools) similarly to auto_tac, but is
  2294 aimed to solve the given subgoal completely.
  2295 
  2296 
  2297 *** General ***
  2298 
  2299 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2300 and `goalw': the theory is no longer needed as an explicit argument -
  2301 the current theory context is used; assumptions are no longer returned
  2302 at the ML-level unless one of them starts with ==> or !!; it is
  2303 recommended to convert to these new commands using isatool fixgoal
  2304 (backup your sources first!);
  2305 
  2306 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2307 the current theory context, and 'theory' to lookup stored theories;
  2308 
  2309 * new theory section 'locale' for declaring constants, assumptions and
  2310 definitions that have local scope;
  2311 
  2312 * new theory section 'nonterminals' for purely syntactic types;
  2313 
  2314 * new theory section 'setup' for generic ML setup functions
  2315 (e.g. package initialization);
  2316 
  2317 * the distribution now includes Isabelle icons: see
  2318 lib/logo/isabelle-{small,tiny}.xpm;
  2319 
  2320 * isatool install - install binaries with absolute references to
  2321 ISABELLE_HOME/bin;
  2322 
  2323 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2324 
  2325 * print mode 'emacs' reserved for Isamode;
  2326 
  2327 * support multiple print (ast) translations per constant name;
  2328 
  2329 * theorems involving oracles are now printed with a suffixed [!];
  2330 
  2331 
  2332 *** HOL ***
  2333 
  2334 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2335 
  2336 * HOL/inductive package reorganized and improved: now supports mutual
  2337 definitions such as
  2338 
  2339   inductive EVEN ODD
  2340     intrs
  2341       null "0 : EVEN"
  2342       oddI "n : EVEN ==> Suc n : ODD"
  2343       evenI "n : ODD ==> Suc n : EVEN"
  2344 
  2345 new theorem list "elims" contains an elimination rule for each of the
  2346 recursive sets; inductive definitions now handle disjunctive premises
  2347 correctly (also ZF);
  2348 
  2349 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2350 "mutual_induct" no longer exists - the induction rule is always
  2351 contained in "induct";
  2352 
  2353 
  2354 * HOL/datatype package re-implemented and greatly improved: now
  2355 supports mutually recursive datatypes such as
  2356 
  2357   datatype
  2358     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2359             | SUM ('a aexp) ('a aexp)
  2360             | DIFF ('a aexp) ('a aexp)
  2361             | NUM 'a
  2362   and
  2363     'a bexp = LESS ('a aexp) ('a aexp)
  2364             | AND ('a bexp) ('a bexp)
  2365             | OR ('a bexp) ('a bexp)
  2366 
  2367 as well as indirectly recursive datatypes such as
  2368 
  2369   datatype
  2370     ('a, 'b) term = Var 'a
  2371                   | App 'b ((('a, 'b) term) list)
  2372 
  2373 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2374 induction on mutually / indirectly recursive datatypes.
  2375 
  2376 Primrec equations are now stored in theory and can be accessed via
  2377 <function_name>.simps.
  2378 
  2379 INCOMPATIBILITIES:
  2380 
  2381   - Theories using datatypes must now have theory Datatype as an
  2382     ancestor.
  2383   - The specific <typename>.induct_tac no longer exists - use the
  2384     generic induct_tac instead.
  2385   - natE has been renamed to nat.exhaust - use exhaust_tac
  2386     instead of res_inst_tac ... natE. Note that the variable
  2387     names in nat.exhaust differ from the names in natE, this
  2388     may cause some "fragile" proofs to fail.
  2389   - The theorems split_<typename>_case and split_<typename>_case_asm
  2390     have been renamed to <typename>.split and <typename>.split_asm.
  2391   - Since default sorts of type variables are now handled correctly,
  2392     some datatype definitions may have to be annotated with explicit
  2393     sort constraints.
  2394   - Primrec definitions no longer require function name and type
  2395     of recursive argument.
  2396 
  2397 Consider using isatool fixdatatype to adapt your theories and proof
  2398 scripts to the new package (backup your sources first!).
  2399 
  2400 
  2401 * HOL/record package: considerably improved implementation; now
  2402 includes concrete syntax for record types, terms, updates; theorems
  2403 for surjective pairing and splitting !!-bound record variables; proof
  2404 support is as follows:
  2405 
  2406   1) standard conversions (selectors or updates applied to record
  2407 constructor terms) are part of the standard simpset;
  2408 
  2409   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2410 made part of standard simpset and claset via addIffs;
  2411 
  2412   3) a tactic for record field splitting (record_split_tac) is part of
  2413 the standard claset (addSWrapper);
  2414 
  2415 To get a better idea about these rules you may retrieve them via
  2416 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2417 the name of your record type.
  2418 
  2419 The split tactic 3) conceptually simplifies by the following rule:
  2420 
  2421   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2422 
  2423 Thus any record variable that is bound by meta-all will automatically
  2424 blow up into some record constructor term, consequently the
  2425 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2426 solve record problems automatically.
  2427 
  2428 
  2429 * reorganized the main HOL image: HOL/Integ and String loaded by
  2430 default; theory Main includes everything;
  2431 
  2432 * automatic simplification of integer sums and comparisons, using cancellation;
  2433 
  2434 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2435 
  2436 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2437 
  2438 * many new identities for unions, intersections, set difference, etc.;
  2439 
  2440 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2441 called split_if, split_split, split_sum_case and split_nat_case (to go
  2442 with add/delsplits);
  2443 
  2444 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2445 (?x::unit) = (); this is made part of the default simpset, which COULD
  2446 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2447 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2448 unit_abs_eta_conv is added in order to counter the effect of
  2449 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2450 %u.f();
  2451 
  2452 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2453 makes more sense);
  2454 
  2455 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2456   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2457   disjointness reasoning but breaking a few old proofs.
  2458 
  2459 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2460 to 'converse' from 'inverse' (for compatibility with ZF and some
  2461 literature);
  2462 
  2463 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2464 the well-founded relation;
  2465 
  2466 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2467     Compl A.  The "Compl" syntax remains available as input syntax for this
  2468     release ONLY.
  2469 
  2470 * HOL/Update: new theory of function updates:
  2471     f(a:=b) == %x. if x=a then b else f x
  2472 may also be iterated as in f(a:=b,c:=d,...);
  2473 
  2474 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2475 
  2476 * HOL/List:
  2477   - new function list_update written xs[i:=v] that updates the i-th
  2478     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2479   - new function `upt' written [i..j(] which generates the list
  2480     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2481     bound write [i..j], which is a shorthand for [i..j+1(].
  2482   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2483 
  2484 * HOL/Arith:
  2485   - removed 'pred' (predecessor) function;
  2486   - generalized some theorems about n-1;
  2487   - many new laws about "div" and "mod";
  2488   - new laws about greatest common divisors (see theory ex/Primes);
  2489 
  2490 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2491 instead of "inverse";
  2492 
  2493 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2494   of the multiset ordering;
  2495 
  2496 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2497   (not included by default);
  2498 
  2499 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2500 
  2501 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2502   programs, i.e. different program variables may have different types.
  2503 
  2504 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2505   [previously, this check worked only if the rewrite rule was unconditional]
  2506   Now rew can involve either definitions or equalities (either == or =).
  2507 
  2508 
  2509 *** ZF ***
  2510 
  2511 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2512   only the theorems proved on ZF.ML;
  2513 
  2514 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2515   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2516   disjointness reasoning but breaking a few old proofs.
  2517 
  2518 * ZF/Update: new theory of function updates
  2519     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2520   may also be iterated as in f(a:=b,c:=d,...);
  2521 
  2522 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2523 
  2524 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2525   [previously, this check worked only if the rewrite rule was unconditional]
  2526   Now rew can involve either definitions or equalities (either == or =).
  2527 
  2528 * case_tac provided for compatibility with HOL
  2529     (like the old excluded_middle_tac, but with subgoals swapped)
  2530 
  2531 
  2532 *** Internal programming interfaces ***
  2533 
  2534 * Pure: several new basic modules made available for general use, see
  2535 also src/Pure/README;
  2536 
  2537 * improved the theory data mechanism to support encapsulation (data
  2538 kind name replaced by private Object.kind, acting as authorization
  2539 key); new type-safe user interface via functor TheoryDataFun; generic
  2540 print_data function becomes basically useless;
  2541 
  2542 * removed global_names compatibility flag -- all theory declarations
  2543 are qualified by default;
  2544 
  2545 * module Pure/Syntax now offers quote / antiquote translation
  2546 functions (useful for Hoare logic etc. with implicit dependencies);
  2547 see HOL/ex/Antiquote for an example use;
  2548 
  2549 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2550 cterm -> thm;
  2551 
  2552 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2553 subgoal;
  2554 
  2555 * Display.print_goals function moved to Locale.print_goals;
  2556 
  2557 * standard print function for goals supports current_goals_markers
  2558 variable for marking begin of proof, end of proof, start of goal; the
  2559 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2560 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2561 for example;
  2562 
  2563 
  2564 
  2565 New in Isabelle98 (January 1998)
  2566 --------------------------------
  2567 
  2568 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2569 
  2570 * changed lexical syntax of terms / types: dots made part of long
  2571 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2572 
  2573 * simpset (and claset) reference variable replaced by functions
  2574 simpset / simpset_ref;
  2575 
  2576 * no longer supports theory aliases (via merge) and non-trivial
  2577 implicit merge of thms' signatures;
  2578 
  2579 * most internal names of constants changed due to qualified names;
  2580 
  2581 * changed Pure/Sequence interface (see Pure/seq.ML);
  2582 
  2583 
  2584 *** General Changes ***
  2585 
  2586 * hierachically structured name spaces (for consts, types, axms, thms
  2587 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2588 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2589 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2590 long_names for fully qualified output names; NOTE: ML programs
  2591 (special tactics, packages etc.) referring to internal names may have
  2592 to be adapted to cope with fully qualified names; in case of severe
  2593 backward campatibility problems try setting 'global_names' at compile
  2594 time to have enrything declared within a flat name space; one may also
  2595 fine tune name declarations in theories via the 'global' and 'local'
  2596 section;
  2597 
  2598 * reimplemented the implicit simpset and claset using the new anytype
  2599 data filed in signatures; references simpset:simpset ref etc. are
  2600 replaced by functions simpset:unit->simpset and
  2601 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2602 to patch your ML files accordingly;
  2603 
  2604 * HTML output now includes theory graph data for display with Java
  2605 applet or isatool browser; data generated automatically via isatool
  2606 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2607 
  2608 * defs may now be conditional; improved rewrite_goals_tac to handle
  2609 conditional equations;
  2610 
  2611 * defs now admits additional type arguments, using TYPE('a) syntax;
  2612 
  2613 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2614 creates a new theory node; implicit merge of thms' signatures is
  2615 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2616 transfer:theory->thm->thm in (rare) cases;
  2617 
  2618 * improved handling of draft signatures / theories; draft thms (and
  2619 ctyps, cterms) are automatically promoted to real ones;
  2620 
  2621 * slightly changed interfaces for oracles: admit many per theory, named
  2622 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2623 
  2624 * print_goals: optional output of const types (set show_consts and
  2625 show_types);
  2626 
  2627 * improved output of warnings (###) and errors (***);
  2628 
  2629 * subgoal_tac displays a warning if the new subgoal has type variables;
  2630 
  2631 * removed old README and Makefiles;
  2632 
  2633 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2634 
  2635 * removed obsolete init_pps and init_database;
  2636 
  2637 * deleted the obsolete tactical STATE, which was declared by
  2638     fun STATE tacfun st = tacfun st st;
  2639 
  2640 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2641 (which abbreviates $HOME);
  2642 
  2643 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2644 use isatool fixseq to adapt your ML programs (this works for fully
  2645 qualified references to the Sequence structure only!);
  2646 
  2647 * use_thy no longer requires writable current directory; it always
  2648 reloads .ML *and* .thy file, if either one is out of date;
  2649 
  2650 
  2651 *** Classical Reasoner ***
  2652 
  2653 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2654 tactics that use classical reasoning to simplify a subgoal without
  2655 splitting it into several subgoals;
  2656 
  2657 * Safe_tac: like safe_tac but uses the default claset;
  2658 
  2659 
  2660 *** Simplifier ***
  2661 
  2662 * added simplification meta rules:
  2663     (asm_)(full_)simplify: simpset -> thm -> thm;
  2664 
  2665 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2666 logics (again);
  2667 
  2668 * added prems argument to simplification procedures;
  2669 
  2670 * HOL, FOL, ZF: added infix function `addsplits':
  2671   instead of `<simpset> setloop (split_tac <thms>)'
  2672   you can simply write `<simpset> addsplits <thms>'
  2673 
  2674 
  2675 *** Syntax ***
  2676 
  2677 * TYPE('a) syntax for type reflection terms;
  2678 
  2679 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2680 
  2681 * pretty printer: changed order of mixfix annotation preference (again!);
  2682 
  2683 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2684 
  2685 
  2686 *** HOL ***
  2687 
  2688 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2689   with `addloop' of the simplifier to faciliate case splitting in premises.
  2690 
  2691 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2692 
  2693 * HOL/Auth: new protocol proofs including some for the Internet
  2694   protocol TLS;
  2695 
  2696 * HOL/Map: new theory of `maps' a la VDM;
  2697 
  2698 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2699 cancelling out common nat summands from =, <, <= (in)equalities, or
  2700 differences; simplification procedures nat_cancel_factor for
  2701 cancelling common factor from =, <, <= (in)equalities over natural
  2702 sums; nat_cancel contains both kinds of procedures, it is installed by
  2703 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2704 
  2705 * HOL/simplifier: terms of the form
  2706   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2707   are rewritten to
  2708   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2709   and those of the form
  2710   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2711   are rewritten to
  2712   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2713 
  2714 * HOL/datatype
  2715   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2716 
  2717   P(t_case f1 ... fn x) =
  2718      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2719         ...
  2720        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2721      )
  2722 
  2723   and a theorem `split_t_case_asm' of the form
  2724 
  2725   P(t_case f1 ... fn x) =
  2726     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2727         ...
  2728        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2729      )
  2730   which can be added to a simpset via `addsplits'. The existing theorems
  2731   expand_list_case and expand_option_case have been renamed to
  2732   split_list_case and split_option_case.
  2733 
  2734 * HOL/Arithmetic:
  2735   - `pred n' is automatically converted to `n-1'.
  2736     Users are strongly encouraged not to use `pred' any longer,
  2737     because it will disappear altogether at some point.
  2738   - Users are strongly encouraged to write "0 < n" rather than
  2739     "n ~= 0". Theorems and proof tools have been modified towards this
  2740     `standard'.
  2741 
  2742 * HOL/Lists:
  2743   the function "set_of_list" has been renamed "set" (and its theorems too);
  2744   the function "nth" now takes its arguments in the reverse order and
  2745   has acquired the infix notation "!" as in "xs!n".
  2746 
  2747 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2748 
  2749 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2750   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2751 
  2752 * HOL/record: extensible records with schematic structural subtyping
  2753 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2754 still lacks various theorems and concrete record syntax;
  2755 
  2756 
  2757 *** HOLCF ***
  2758 
  2759 * removed "axioms" and "generated by" sections;
  2760 
  2761 * replaced "ops" section by extended "consts" section, which is capable of
  2762   handling the continuous function space "->" directly;
  2763 
  2764 * domain package:
  2765   . proves theorems immediately and stores them in the theory,
  2766   . creates hierachical name space,
  2767   . now uses normal mixfix annotations (instead of cinfix...),
  2768   . minor changes to some names and values (for consistency),
  2769   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2770   . separator between mutual domain defs: changed "," to "and",
  2771   . improved handling of sort constraints;  now they have to
  2772     appear on the left-hand side of the equations only;
  2773 
  2774 * fixed LAM <x,y,zs>.b syntax;
  2775 
  2776 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2777 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2778 
  2779 
  2780 *** FOL and ZF ***
  2781 
  2782 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2783   with `addloop' of the simplifier to faciliate case splitting in premises.
  2784 
  2785 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2786 in HOL, they strip ALL and --> from proved theorems;
  2787 
  2788 
  2789 
  2790 New in Isabelle94-8 (May 1997)
  2791 ------------------------------
  2792 
  2793 *** General Changes ***
  2794 
  2795 * new utilities to build / run / maintain Isabelle etc. (in parts
  2796 still somewhat experimental); old Makefiles etc. still functional;
  2797 
  2798 * new 'Isabelle System Manual';
  2799 
  2800 * INSTALL text, together with ./configure and ./build scripts;
  2801 
  2802 * reimplemented type inference for greater efficiency, better error
  2803 messages and clean internal interface;
  2804 
  2805 * prlim command for dealing with lots of subgoals (an easier way of
  2806 setting goals_limit);
  2807 
  2808 
  2809 *** Syntax ***
  2810 
  2811 * supports alternative (named) syntax tables (parser and pretty
  2812 printer); internal interface is provided by add_modesyntax(_i);
  2813 
  2814 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2815 be used in conjunction with the Isabelle symbol font; uses the
  2816 "symbols" syntax table;
  2817 
  2818 * added token_translation interface (may translate name tokens in
  2819 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2820 the current print_mode); IMPORTANT: user print translation functions
  2821 are responsible for marking newly introduced bounds
  2822 (Syntax.mark_boundT);
  2823 
  2824 * token translations for modes "xterm" and "xterm_color" that display
  2825 names in bold, underline etc. or colors (which requires a color
  2826 version of xterm);
  2827 
  2828 * infixes may now be declared with names independent of their syntax;
  2829 
  2830 * added typed_print_translation (like print_translation, but may
  2831 access type of constant);
  2832 
  2833 
  2834 *** Classical Reasoner ***
  2835 
  2836 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2837 some limitations.  Blast_tac...
  2838   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2839   + ignores elimination rules that don't have the correct format
  2840         (the conclusion MUST be a formula variable)
  2841   + ignores types, which can make HOL proofs fail
  2842   + rules must not require higher-order unification, e.g. apply_type in ZF
  2843     [message "Function Var's argument not a bound variable" relates to this]
  2844   + its proof strategy is more general but can actually be slower
  2845 
  2846 * substitution with equality assumptions no longer permutes other
  2847 assumptions;
  2848 
  2849 * minor changes in semantics of addafter (now called addaltern); renamed
  2850 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2851 (and access functions for it);
  2852 
  2853 * improved combination of classical reasoner and simplifier:
  2854   + functions for handling clasimpsets
  2855   + improvement of addss: now the simplifier is called _after_ the
  2856     safe steps.
  2857   + safe variant of addss called addSss: uses safe simplifications
  2858     _during_ the safe steps. It is more complete as it allows multiple
  2859     instantiations of unknowns (e.g. with slow_tac).
  2860 
  2861 *** Simplifier ***
  2862 
  2863 * added interface for simplification procedures (functions that
  2864 produce *proven* rewrite rules on the fly, depending on current
  2865 redex);
  2866 
  2867 * ordering on terms as parameter (used for ordered rewriting);
  2868 
  2869 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2870 
  2871 * the solver is now split into a safe and an unsafe part.
  2872 This should be invisible for the normal user, except that the
  2873 functions setsolver and addsolver have been renamed to setSolver and
  2874 addSolver; added safe_asm_full_simp_tac;
  2875 
  2876 
  2877 *** HOL ***
  2878 
  2879 * a generic induction tactic `induct_tac' which works for all datatypes and
  2880 also for type `nat';
  2881 
  2882 * a generic case distinction tactic `exhaust_tac' which works for all
  2883 datatypes and also for type `nat';
  2884 
  2885 * each datatype comes with a function `size';
  2886 
  2887 * patterns in case expressions allow tuple patterns as arguments to
  2888 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2889 
  2890 * primrec now also works with type nat;
  2891 
  2892 * recdef: a new declaration form, allows general recursive functions to be
  2893 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2894 
  2895 * the constant for negation has been renamed from "not" to "Not" to
  2896 harmonize with FOL, ZF, LK, etc.;
  2897 
  2898 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2899 infinite lists;
  2900 
  2901 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2902 
  2903 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2904 problems in commutative rings, using axiomatic type classes for + and *;
  2905 
  2906 * more examples in HOL/MiniML and HOL/Auth;
  2907 
  2908 * more default rewrite rules for quantifiers, union/intersection;
  2909 
  2910 * a new constant `arbitrary == @x.False';
  2911 
  2912 * HOLCF/IOA replaces old HOL/IOA;
  2913 
  2914 * HOLCF changes: derived all rules and arities
  2915   + axiomatic type classes instead of classes
  2916   + typedef instead of faking type definitions
  2917   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2918   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2919   + eliminated the types void, one, tr
  2920   + use unit lift and bool lift (with translations) instead of one and tr
  2921   + eliminated blift from Lift3.thy (use Def instead of blift)
  2922   all eliminated rules are derived as theorems --> no visible changes ;
  2923 
  2924 
  2925 *** ZF ***
  2926 
  2927 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2928 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2929 as ZF_cs addSIs [equalityI];
  2930 
  2931 
  2932 
  2933 New in Isabelle94-7 (November 96)
  2934 ---------------------------------
  2935 
  2936 * allowing negative levels (as offsets) in prlev and choplev;
  2937 
  2938 * super-linear speedup for large simplifications;
  2939 
  2940 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2941 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2942 FAIL); can suppress it using the command Delsimps (ex_simps @
  2943 all_simps); De Morgan laws are also now included, by default;
  2944 
  2945 * improved printing of ==>  :  ~:
  2946 
  2947 * new object-logic "Sequents" adds linear logic, while replacing LK
  2948 and Modal (thanks to Sara Kalvala);
  2949 
  2950 * HOL/Auth: correctness proofs for authentication protocols;
  2951 
  2952 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2953 examples on HOL/Auth);
  2954 
  2955 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2956 the rewriter and classical reasoner simultaneously;
  2957 
  2958 * function uresult no longer returns theorems in "standard" format;
  2959 regain previous version by: val uresult = standard o uresult;
  2960 
  2961 
  2962 
  2963 New in Isabelle94-6
  2964 -------------------
  2965 
  2966 * oracles -- these establish an interface between Isabelle and trusted
  2967 external reasoners, which may deliver results as theorems;
  2968 
  2969 * proof objects (in particular record all uses of oracles);
  2970 
  2971 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2972 
  2973 * "constdefs" section in theory files;
  2974 
  2975 * "primrec" section (HOL) no longer requires names;
  2976 
  2977 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2978 
  2979 
  2980 
  2981 New in Isabelle94-5
  2982 -------------------
  2983 
  2984 * reduced space requirements;
  2985 
  2986 * automatic HTML generation from theories;
  2987 
  2988 * theory files no longer require "..." (quotes) around most types;
  2989 
  2990 * new examples, including two proofs of the Church-Rosser theorem;
  2991 
  2992 * non-curried (1994) version of HOL is no longer distributed;
  2993 
  2994 
  2995 
  2996 New in Isabelle94-4
  2997 -------------------
  2998 
  2999 * greatly reduced space requirements;
  3000 
  3001 * theory files (.thy) no longer require \...\ escapes at line breaks;
  3002 
  3003 * searchable theorem database (see the section "Retrieving theorems" on
  3004 page 8 of the Reference Manual);
  3005 
  3006 * new examples, including Grabczewski's monumental case study of the
  3007 Axiom of Choice;
  3008 
  3009 * The previous version of HOL renamed to Old_HOL;
  3010 
  3011 * The new version of HOL (previously called CHOL) uses a curried syntax
  3012 for functions.  Application looks like f a b instead of f(a,b);
  3013 
  3014 * Mutually recursive inductive definitions finally work in HOL;
  3015 
  3016 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3017 translates to the operator "split";
  3018 
  3019 
  3020 
  3021 New in Isabelle94-3
  3022 -------------------
  3023 
  3024 * new infix operator, addss, allowing the classical reasoner to
  3025 perform simplification at each step of its search.  Example:
  3026         fast_tac (cs addss ss)
  3027 
  3028 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3029 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3030 look like (a,b) instead of <a,b>;
  3031 
  3032 * PLEASE NOTE: CHOL will eventually replace HOL!
  3033 
  3034 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3035 It translates to the operator "split".  A new theory of integers is available;
  3036 
  3037 * In ZF, integer numerals now denote two's-complement binary integers.
  3038 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3039 
  3040 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3041 of the Axiom of Choice;
  3042 
  3043 
  3044 
  3045 New in Isabelle94-2
  3046 -------------------
  3047 
  3048 * Significantly faster resolution;
  3049 
  3050 * the different sections in a .thy file can now be mixed and repeated
  3051 freely;
  3052 
  3053 * Database of theorems for FOL, HOL and ZF.  New
  3054 commands including qed, qed_goal and bind_thm store theorems in the database.
  3055 
  3056 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3057 a given theory (thms_of), or find out what theory a theorem was proved in
  3058 (theory_of_thm);
  3059 
  3060 * Bugs fixed in the inductive definition and datatype packages;
  3061 
  3062 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3063 and HOL_dup_cs obsolete;
  3064 
  3065 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3066 have been removed;
  3067 
  3068 * Simpler definition of function space in ZF;
  3069 
  3070 * new results about cardinal and ordinal arithmetic in ZF;
  3071 
  3072 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3073 types;
  3074 
  3075 
  3076 $Id$