NEWS
author ballarin
Fri May 27 17:10:23 2005 +0200 (2005-05-27)
changeset 16104 dab13c4685ba
parent 16102 c5f6726d9bb1
child 16111 d06dc7975731
permissions -rw-r--r--
Typo.
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryn>
    13   begin
    14 
    15   optionally also with a "files" section. The syntax
    16 
    17   theory <name> = <theory1> + ... + <theoryn>:
    18 
    19   will still be supported for some time but will eventually disappear.
    20   The syntax of old-style theories has not changed.
    21 
    22 * Theory loader: parent theories can now also be referred to via
    23   relative and absolute paths.
    24 
    25 * Provers/quasi.ML: new transitivity reasoners for transitivity only
    26   and quasi orders.
    27 
    28 * Provers/trancl.ML: new transitivity reasoner for transitive and
    29   reflexive-transitive closure of relations.
    30 
    31 * Provers/blast.ML: new reference depth_limit to make blast's depth
    32   limit (previously hard-coded with a value of 20) user-definable.
    33 
    34 * Provers: new version of the subst method, for single-step rewriting: it now
    35   works in bound variable contexts. New is subst (asm), for rewriting an
    36   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    37   subterm than the original subst method, which is still available under the
    38   name simplesubst.
    39 
    40 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    41   More generally, erule now works even if the major premise of the elimination rule
    42   contains !! or ==>.
    43 
    44 * Pure: considerably improved version of 'constdefs' command.  Now
    45   performs automatic type-inference of declared constants; additional
    46   support for local structure declarations (cf. locales and HOL
    47   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    48   to observe strictly sequential dependencies of definitions within a
    49   single 'constdefs' section; moreover, the declared name needs to be
    50   an identifier.  If all fails, consider to fall back on 'consts' and
    51   'defs' separately.
    52 
    53 * Pure: improved indexed syntax and implicit structures.  First of
    54   all, indexed syntax provides a notational device for subscripted
    55   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    56   expressions.  Secondly, in a local context with structure
    57   declarations, number indexes \<^sub>n or the empty index (default
    58   number 1) refer to a certain fixed variable implicitly; option
    59   show_structs controls printing of implicit structures.  Typical
    60   applications of these concepts involve record types and locales.
    61 
    62 * Pure: clear separation of logical types and nonterminals, where the
    63   latter may only occur in 'syntax' specifications or type
    64   abbreviations.  Before that distinction was only partially
    65   implemented via type class "logic" vs. "{}".  Potential
    66   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    67   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    68   specifications may require further adaption (e.g. Cube/Base.thy).
    69 
    70 * Pure: removed obsolete type class "logic", use the top sort {}
    71   instead.  Note that non-logical types should be declared as
    72   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    73   object-logic specifications.
    74 
    75 * Pure: command 'no_syntax' removes grammar declarations (and
    76   translations) resulting from the given syntax specification, which
    77   is interpreted in the same manner as for the 'syntax' command.
    78 
    79 * Pure: print_tac now outputs the goal through the trace channel.
    80 
    81 * Pure: reference NameSpace.unique_names included.  If true the
    82   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    83   yet). If false the first entry wins (as during parsing). Default
    84   value is true.
    85 
    86 * Pure: tuned internal renaming of symbolic identifiers -- attach
    87   primes instead of base 26 numbers.
    88 
    89 * Pure: new flag show_question_marks controls printing of leading
    90   question marks in schematic variable names.
    91 
    92 * Pure: new version of thms_containing that searches for a list of
    93   criteria instead of a list of constants. Known criteria are: intro,
    94   elim, dest, name:string, and any term. Criteria can be preceded by
    95   '-' to select theorems that do not match. Intro, elim, dest select
    96   theorems that match the current goal, name:s selects theorems whose
    97   fully qualified name contain s.  Any other term is interpreted as
    98   pattern and selects all theorem matching the pattern. Available in
    99   ProofGeneral under ProofGeneral -> Find Theorems or C-c C-f.
   100 
   101   Example: C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
   102 
   103   prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   104   matching the current goal as introduction rule and not having "HOL." 
   105   in their name (i.e. not being defined in theory HOL).
   106 
   107 * Pure/Syntax: In schematic variable names, *any* symbol following
   108   \<^isub> or \<^isup> is now treated as part of the base name.  For
   109   example, the following works without printing of ugly ".0" indexes:
   110 
   111     lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   112       by simp
   113 
   114 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   115 
   116 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   117   specified in mixfix annotations as "(00...)".
   118 
   119 * Pure/Syntax: 'advanced' translation functions (parse_translation
   120   etc.) may depend on the signature of the theory context being
   121   presently used for parsing/printing, see also isar-ref manual.
   122 
   123 * Pure/Simplifier: you can control the depth to which conditional rewriting
   124   is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth Limit.
   125 
   126 * Pure/Simplifier: simplification procedures may now take the current
   127   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   128   interface), which is very useful for calling the Simplifier
   129   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   130   simprocs is gone -- use prems_of_ss on the simpset instead.
   131   Moreover, the low-level mk_simproc no longer applies Logic.varify
   132   internally, to allow for use in a context of fixed variables.
   133 
   134 * Isar debugging: new reference Toplevel.debug; default false.  Set to
   135   make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   136   
   137 * Locales: modifications regarding "includes"
   138   - "includes" disallowed in declaration of named locales (command "locale").
   139   - Fixed parameter management in theorem generation for goals with "includes".
   140     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   141 
   142 * Locales: locale expressions permit optional mixfix redeclaration for
   143   renamed parameters.
   144 
   145 * Locales: new commands for the interpretation of locale expressions
   146   in theories (interpretation) and proof contexts (interpret).  These take an
   147   instantiation of the locale parameters and compute proof obligations from
   148   the instantiated specification.  After the obligations have been discharged,
   149   the instantiated theorems of the locale are added to the theory or proof
   150   context.  Interpretation is smart in that already active interpretations
   151   do not occur in proof obligations, neither are instantiated theorems stored
   152   in duplicate.
   153   Use print_interps to inspect active interpretations of a particular locale.
   154   For details, see the Isar Reference manual.
   155 
   156 * Locales: proper static binding of attribute syntax -- i.e. types /
   157   terms / facts mentioned as arguments are always those of the locale
   158   definition context, independently of the context of later
   159   invocations.  Moreover, locale operations (renaming and type / term
   160   instantiation) are applied to attribute arguments as expected.
   161 
   162   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   163   of actual attributes; rare situations may require Attrib.attribute
   164   to embed those attributes into Attrib.src that lack concrete syntax.
   165 
   166   Attribute implementations need to cooperate properly with the static
   167   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   168   Attrib.XXX_thm etc. already do the right thing without further
   169   intervention.  Only unusual applications -- such as "where" or "of"
   170   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   171   both on the context and the facts involved -- may have to assign
   172   parsed values to argument tokens explicitly.
   173 
   174 * Attributes 'induct' and 'cases': type or set names may now be
   175   locally fixed variables as well.
   176 
   177 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   178   selections of theorems in named facts via indices.
   179 
   180 * Pure: reorganized bootstrapping of the Pure theories; CPure is now
   181   derived from Pure, which contains all common declarations already.
   182   Both theories are defined via plain Isabelle/Isar .thy files.
   183   INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   184   CPure.elim / CPure.dest attributes) now appear in the Pure name
   185   space; use isatool fixcpure to adapt your theory and ML sources.
   186 
   187 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   188   is peformed already.  Object-logics merely need to finish their
   189   initial simpset configuration as before.
   190 
   191 
   192 *** Document preparation ***
   193 
   194 * Several new antiquotation:
   195 
   196   @{term_type term} prints a term with its type annotated;
   197 
   198   @{typeof term} prints the type of a term;
   199 
   200   @{const const} is the same as @{term const}, but checks
   201     that the argument is a known logical constant;
   202 
   203   @{term_style style term} and @{thm_style style thm} print a term or
   204     theorem applying a "style" to it
   205 
   206   Predefined styles are "lhs" and "rhs" printing the lhs/rhs of
   207   definitions, equations, inequations etc. and "conclusion" printing
   208   only the conclusion of a meta-logical statement theorem.  Styles may
   209   be defined via TermStyle.add_style in ML.  See the "LaTeX Sugar"
   210   document for more information.
   211 
   212 * Antiquotations now provide the option 'locale=NAME' to specify an
   213   alternative context used for evaluating and printing the subsequent
   214   argument, as in @{thm [locale=LC] fold_commute}, for example.
   215 
   216 * Commands 'display_drafts' and 'print_drafts' perform simple output
   217   of raw sources.  Only those symbols that do not require additional
   218   LaTeX packages (depending on comments in isabellesym.sty) are
   219   displayed properly, everything else is left verbatim.  We use
   220   isatool display and isatool print as front ends; these are subject
   221   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   222 
   223 * Proof scripts as well as some other commands such as ML or
   224   parse/print_translation can now be hidden in the document.  Hiding
   225   is enabled by default, and can be disabled either via the option '-H
   226   false' of isatool usedir or by resetting the reference variable
   227   IsarOutput.hide_commands. Additional commands to be hidden may be
   228   declared using IsarOutput.add_hidden_commands.
   229 
   230 
   231 *** HOL ***
   232 
   233 * Datatype induction via method `induct' now preserves the name of the
   234   induction variable. For example, when proving P(xs::'a list) by induction
   235   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   236   P(list) ==> P(a#list) as previously.
   237 
   238 * HOL/record: reimplementation of records. Improved scalability for
   239   records with many fields, avoiding performance problems for type
   240   inference. Records are no longer composed of nested field types, but
   241   of nested extension types. Therefore the record type only grows
   242   linear in the number of extensions and not in the number of fields.
   243   The top-level (users) view on records is preserved.  Potential
   244   INCOMPATIBILITY only in strange cases, where the theory depends on
   245   the old record representation. The type generated for a record is
   246   called <record_name>_ext_type.
   247 
   248 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   249   enabled to skip the proofs triggered by a record definition or a
   250   simproc (if quick_and_dirty is enabled). Definitions of large
   251   records can take quite long.
   252 
   253 * HOL/record: "record_upd_simproc" for simplification of multiple
   254   record updates enabled by default.  Moreover, trivial updates are
   255   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   256   occasionally, since simplification is more powerful by default.
   257 
   258 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   259 
   260   syntax (epsilon)
   261     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   262 
   263   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   264   and x-symbol; use option '-m epsilon' to get it actually printed.
   265   Moreover, the mathematically important symbolic identifier
   266   \<epsilon> becomes available as variable, constant etc.
   267 
   268 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   269   Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   270   is \<ge>.
   271 
   272 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}" (and similarly for
   273   "\<in>" instead of ":").
   274 
   275 * HOL/SetInterval: The syntax for open intervals has changed:
   276 
   277   Old         New
   278   {..n(}   -> {..<n}
   279   {)n..}   -> {n<..}
   280   {m..n(}  -> {m..<n}
   281   {)m..n}  -> {m<..n}
   282   {)m..n(} -> {m<..<n}
   283 
   284   The old syntax is still supported but will disappear in the future.
   285   For conversion use the following emacs search and replace patterns:
   286 
   287   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   288   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   289 
   290   They are not perfect but work quite well.
   291 
   292 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   293 
   294   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   295   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   296 
   297   There is new syntax for summation over finite sets:
   298 
   299   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   300   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   301   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   302   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   303 
   304   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   305   now translates into 'setsum' as above.
   306 
   307 * HOL: Finite set induction: In Isar proofs, the insert case is now
   308   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   309 
   310 * HOL/Simplifier:
   311 
   312   - Is now set up to reason about transitivity chains involving "trancl"
   313   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   314   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   315   occasionally as simplification may now solve more goals than previously.
   316 
   317   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   318   all partial orders (class "order"), in particular numbers and sets. For
   319   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   320 
   321   - Simproc for "let x = a in f x"
   322   If a is a free or bound variable or a constant then the let is unfolded.
   323   Otherwise first a is simplified to a', and then f a' is simplified to
   324   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   325   otherwise we unfold the let and arrive at g. The simproc can be 
   326   enabled/disabled by the reference use_let_simproc. Potential
   327   INCOMPATIBILITY since simplification is more powerful by default.
   328 
   329 * HOL: The 'refute' command has been extended to support a much larger
   330   fragment of HOL, including axiomatic type classes, constdefs and typedefs,
   331   inductive datatypes and recursion.
   332 
   333 
   334 *** HOLCF ***
   335 
   336 * HOLCF: discontinued special version of 'constdefs' (which used to
   337   support continuous functions) in favor of the general Pure one with
   338   full type-inference.
   339 
   340 
   341 *** ZF ***
   342 
   343 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   344   First Isomorphism Theorem (on quotienting by the kernel of a
   345   homomorphism).
   346 
   347 * ZF/Simplifier: install second copy of type solver that actually
   348   makes use of TC rules declared to Isar proof contexts (or locales);
   349   the old version is still required for ML proof scripts.
   350 
   351 
   352 *** System ***
   353 
   354 * Allow symlinks to all proper Isabelle executables (Isabelle,
   355   isabelle, isatool etc.).
   356 
   357 * isabelle-process: Poly/ML no longer needs Perl to run an interactive
   358   session.
   359 
   360 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   361   isatool doc, isatool mkdir, display_drafts etc.).
   362 
   363 * isatool usedir: option -f allows specification of the ML file to be
   364   used by Isabelle; default is ROOT.ML.
   365 
   366 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   367   (containing Boolean satisfiability problems) into Isabelle/HOL
   368   theories.
   369 
   370 
   371 *** ML ***
   372 
   373 * Pure/library.ML no longer defines its own option datatype, but uses
   374   that of the SML basis, which has constructors NONE and SOME instead
   375   of None and Some, as well as exception Option.Option instead of
   376   OPTION.  The functions the, if_none, is_some, is_none have been
   377   adapted accordingly, while Option.map replaces apsome.
   378 
   379 * The exception LIST is no more, the standard exceptions Empty and
   380   Subscript, as well as Library.UnequalLengths are used instead.  This
   381   means that function like Library.hd and Library.tl are gone, as the
   382   standard hd and tl functions suffice.
   383 
   384   A number of basic functions are now no longer exported to the ML
   385   toplevel, as they are variants of standard functions.  The following
   386   suggests how one can translate existing code:
   387 
   388     rev_append xs ys = List.revAppend (xs, ys)
   389     nth_elem (i, xs) = List.nth (xs, i)
   390     last_elem xs = List.last xs
   391     flat xss = List.concat xss
   392     seq fs = app fs
   393     partition P xs = List.partition P xs
   394     filter P xs = List.filter P xs
   395     mapfilter f xs = List.mapPartial f xs
   396 
   397 * Pure: output via the Isabelle channels of writeln/warning/error
   398   etc. is now passed through Output.output, with a hook for arbitrary
   399   transformations depending on the print_mode (cf. Output.add_mode --
   400   the first active mode that provides a output function wins).
   401   Already formatted output may be embedded into further text via
   402   Output.raw; the result of Pretty.string_of/str_of and derived
   403   functions (string_of_term/cterm/thm etc.) is already marked raw to
   404   accommodate easy composition of diagnostic messages etc.
   405   Programmers rarely need to care about Output.output or Output.raw at
   406   all, with some notable exceptions: Output.output is required when
   407   bypassing the standard channels (writeln etc.), or in token
   408   translations to produce properly formatted results; Output.raw is
   409   required when capturing already output material that will eventually
   410   be presented to the user a second time.  For the default print mode,
   411   both Output.output and Output.raw have no effect.
   412 
   413 * Provers: Simplifier and Classical Reasoner now support proof context
   414   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   415   components are stored in the theory and patched into the
   416   simpset/claset when used in an Isar proof context.  Context
   417   dependent components are maintained by the following theory
   418   operations:
   419 
   420     Simplifier.add_context_simprocs
   421     Simplifier.del_context_simprocs
   422     Simplifier.set_context_subgoaler
   423     Simplifier.reset_context_subgoaler
   424     Simplifier.add_context_looper
   425     Simplifier.del_context_looper
   426     Simplifier.add_context_unsafe_solver
   427     Simplifier.add_context_safe_solver
   428 
   429     Classical.add_context_safe_wrapper
   430     Classical.del_context_safe_wrapper
   431     Classical.add_context_unsafe_wrapper
   432     Classical.del_context_unsafe_wrapper
   433 
   434   IMPORTANT NOTE: proof tools (methods etc.) need to use
   435   local_simpset_of and local_claset_of to instead of the primitive
   436   Simplifier.get_local_simpset and Classical.get_local_claset,
   437   respectively, in order to see the context dependent fields!
   438 
   439 
   440 
   441 New in Isabelle2004 (April 2004)
   442 --------------------------------
   443 
   444 *** General ***
   445 
   446 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   447   Replaces linorder.ML.
   448 
   449 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   450   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   451   (\<a>...\<z>), are now considered normal letters, and can therefore
   452   be used anywhere where an ASCII letter (a...zA...Z) has until
   453   now. COMPATIBILITY: This obviously changes the parsing of some
   454   terms, especially where a symbol has been used as a binder, say
   455   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   456   as an identifier.  Fix it by inserting a space around former
   457   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   458   existing theory and ML files.
   459 
   460 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   461 
   462 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   463   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   464   a normal (but invisible) letter. For multiple letter subscripts repeat
   465   \<^isub> like this: x\<^isub>1\<^isub>2.
   466 
   467 * Pure: There are now sub-/superscripts that can span more than one
   468   character. Text between \<^bsub> and \<^esub> is set in subscript in
   469   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   470   superscript. The new control characters are not identifier parts.
   471 
   472 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   473   content of "..." to the latex file instead of \isacntrl... . The "..."
   474   may consist of any printable characters excluding the end bracket >.
   475 
   476 * Pure: Using new Isar command "finalconsts" (or the ML functions
   477   Theory.add_finals or Theory.add_finals_i) it is now possible to
   478   declare constants "final", which prevents their being given a definition
   479   later.  It is useful for constants whose behaviour is fixed axiomatically
   480   rather than definitionally, such as the meta-logic connectives.
   481 
   482 * Pure: 'instance' now handles general arities with general sorts
   483   (i.e. intersections of classes),
   484 
   485 * Presentation: generated HTML now uses a CSS style sheet to make layout
   486   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   487   It can be changed to alter the colors/layout of generated pages.
   488 
   489 
   490 *** Isar ***
   491 
   492 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   493   cut_tac, subgoal_tac and thin_tac:
   494   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   495     locales are no longer forced to write Isar proof scripts.
   496     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   497     emulations.
   498   - INCOMPATIBILITY: names of variables to be instantiated may no
   499     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   500     This is consistent with the instantiation attribute "where".
   501 
   502 * Attributes "where" and "of":
   503   - Now take type variables of instantiated theorem into account when reading
   504     the instantiation string.  This fixes a bug that caused instantiated
   505     theorems to have too special types in some circumstances.
   506   - "where" permits explicit instantiations of type variables.
   507 
   508 * Calculation commands "moreover" and "also" no longer interfere with
   509   current facts ("this"), admitting arbitrary combinations with "then"
   510   and derived forms.
   511 
   512 * Locales:
   513   - Goal statements involving the context element "includes" no longer
   514     generate theorems with internal delta predicates (those ending on
   515     "_axioms") in the premise.
   516     Resolve particular premise with <locale>.intro to obtain old form.
   517   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   518     specification and "includes" elements in goal statement.
   519   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   520     [intro?] and [elim?] (respectively) by default.
   521   - Experimental command for instantiation of locales in proof contexts:
   522         instantiate <label>[<attrs>]: <loc>
   523     Instantiates locale <loc> and adds all its theorems to the current context
   524     taking into account their attributes.  Label and attrs are optional
   525     modifiers, like in theorem declarations.  If present, names of
   526     instantiated theorems are qualified with <label>, and the attributes
   527     <attrs> are applied after any attributes these theorems might have already.
   528       If the locale has assumptions, a chained fact of the form
   529     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   530     are derived.  The command does not support old-style locales declared
   531     with "locale (open)".
   532       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   533 
   534 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   535   (Isar) contexts.
   536 
   537 
   538 *** HOL ***
   539 
   540 * Proof import: new image HOL4 contains the imported library from
   541   the HOL4 system with about 2500 theorems. It is imported by
   542   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   543   can be used like any other Isabelle image.  See
   544   HOL/Import/HOL/README for more information.
   545 
   546 * Simplifier:
   547   - Much improved handling of linear and partial orders.
   548     Reasoners for linear and partial orders are set up for type classes
   549     "linorder" and "order" respectively, and are added to the default simpset
   550     as solvers.  This means that the simplifier can build transitivity chains
   551     to solve goals from the assumptions.
   552   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   553     of blast or auto after simplification become unnecessary because the goal
   554     is solved by simplification already.
   555 
   556 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   557     all proved in axiomatic type classes for semirings, rings and fields.
   558 
   559 * Numerics:
   560   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   561     now formalized using the Ring_and_Field theory mentioned above.
   562   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   563     than before, because now they are set up once in a generic manner.
   564   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   565     Look for the general versions in Ring_and_Field (and Power if they concern
   566     exponentiation).
   567 
   568 * Type "rat" of the rational numbers is now available in HOL-Complex.
   569 
   570 * Records:
   571   - Record types are now by default printed with their type abbreviation
   572     instead of the list of all field types. This can be configured via
   573     the reference "print_record_type_abbr".
   574   - Simproc "record_upd_simproc" for simplification of multiple updates added
   575     (not enabled by default).
   576   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   577     EX x. x = sel r to True (not enabled by default).
   578   - Tactic "record_split_simp_tac" to split and simplify records added.
   579 
   580 * 'specification' command added, allowing for definition by
   581   specification.  There is also an 'ax_specification' command that
   582   introduces the new constants axiomatically.
   583 
   584 * arith(_tac) is now able to generate counterexamples for reals as well.
   585 
   586 * HOL-Algebra: new locale "ring" for non-commutative rings.
   587 
   588 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   589   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   590 
   591 * HOL-Matrix: a first theory for matrices in HOL with an application of
   592   matrix theory to linear programming.
   593 
   594 * Unions and Intersections:
   595   The latex output syntax of UN and INT has been changed
   596   from "\Union x \in A. B" to "\Union_{x \in A} B"
   597   i.e. the index formulae has become a subscript.
   598   Similarly for "\Union x. B", and for \Inter instead of \Union.
   599 
   600 * Unions and Intersections over Intervals:
   601   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   602   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   603   like in normal math, and corresponding versions for < and for intersection.
   604 
   605 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   606   lexicographic dictonary ordering has been added as "lexord".
   607 
   608 * ML: the legacy theory structures Int and List have been removed. They had
   609   conflicted with ML Basis Library structures having the same names.
   610 
   611 * 'refute' command added to search for (finite) countermodels.  Only works
   612   for a fragment of HOL.  The installation of an external SAT solver is
   613   highly recommended.  See "HOL/Refute.thy" for details.
   614 
   615 * 'quickcheck' command: Allows to find counterexamples by evaluating
   616   formulae under an assignment of free variables to random values.
   617   In contrast to 'refute', it can deal with inductive datatypes,
   618   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   619   for examples.
   620 
   621 
   622 *** HOLCF ***
   623 
   624 * Streams now come with concatenation and are part of the HOLCF image
   625 
   626 
   627 
   628 New in Isabelle2003 (May 2003)
   629 ------------------------------
   630 
   631 *** General ***
   632 
   633 * Provers/simplifier:
   634 
   635   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   636     Assumptions are now subject to complete mutual simplification,
   637     not just from left to right. The simplifier now preserves
   638     the order of assumptions.
   639 
   640     Potential INCOMPATIBILITY:
   641 
   642     -- simp sometimes diverges where the old version did
   643        not, e.g. invoking simp on the goal
   644 
   645         [| P (f x); y = x; f x = f y |] ==> Q
   646 
   647        now gives rise to the infinite reduction sequence
   648 
   649         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   650 
   651        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   652        kind of problem.
   653 
   654     -- Tactics combining classical reasoner and simplification (such as auto)
   655        are also affected by this change, because many of them rely on
   656        simp. They may sometimes diverge as well or yield a different numbers
   657        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   658        in case of problems. Sometimes subsequent calls to the classical
   659        reasoner will fail because a preceeding call to the simplifier too
   660        eagerly simplified the goal, e.g. deleted redundant premises.
   661 
   662   - The simplifier trace now shows the names of the applied rewrite rules
   663 
   664   - You can limit the number of recursive invocations of the simplifier
   665     during conditional rewriting (where the simplifie tries to solve the
   666     conditions before applying the rewrite rule):
   667     ML "simp_depth_limit := n"
   668     where n is an integer. Thus you can force termination where previously
   669     the simplifier would diverge.
   670 
   671   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   672 
   673   - No longer aborts on failed congruence proof.  Instead, the
   674     congruence is ignored.
   675 
   676 * Pure: New generic framework for extracting programs from constructive
   677   proofs. See HOL/Extraction.thy for an example instantiation, as well
   678   as HOL/Extraction for some case studies.
   679 
   680 * Pure: The main goal of the proof state is no longer shown by default, only
   681 the subgoals. This behaviour is controlled by a new flag.
   682    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   683 (ML: Proof.show_main_goal).
   684 
   685 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   686 rules whose conclusion matches subgoal 1:
   687       PG menu: Isabelle/Isar -> Show me -> matching rules
   688 The rules are ordered by how closely they match the subgoal.
   689 In particular, rules that solve a subgoal outright are displayed first
   690 (or rather last, the way they are printed).
   691 (ML: ProofGeneral.print_intros())
   692 
   693 * Pure: New flag trace_unify_fail causes unification to print
   694 diagnostic information (PG: in trace buffer) when it fails. This is
   695 useful for figuring out why single step proofs like rule, erule or
   696 assumption failed.
   697 
   698 * Pure: Locale specifications now produce predicate definitions
   699 according to the body of text (covering assumptions modulo local
   700 definitions); predicate "loc_axioms" covers newly introduced text,
   701 while "loc" is cumulative wrt. all included locale expressions; the
   702 latter view is presented only on export into the global theory
   703 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   704 on the old view without predicates;
   705 
   706 * Pure: predefined locales "var" and "struct" are useful for sharing
   707 parameters (as in CASL, for example); just specify something like
   708 ``var x + var y + struct M'' as import;
   709 
   710 * Pure: improved thms_containing: proper indexing of facts instead of
   711 raw theorems; check validity of results wrt. current name space;
   712 include local facts of proof configuration (also covers active
   713 locales), cover fixed variables in index; may use "_" in term
   714 specification; an optional limit for the number of printed facts may
   715 be given (the default is 40);
   716 
   717 * Pure: disallow duplicate fact bindings within new-style theory files
   718 (batch-mode only);
   719 
   720 * Provers: improved induct method: assumptions introduced by case
   721 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   722 the goal statement); "foo" still refers to all facts collectively;
   723 
   724 * Provers: the function blast.overloaded has been removed: all constants
   725 are regarded as potentially overloaded, which improves robustness in exchange
   726 for slight decrease in efficiency;
   727 
   728 * Provers/linorder: New generic prover for transitivity reasoning over
   729 linear orders.  Note: this prover is not efficient!
   730 
   731 * Isar: preview of problems to finish 'show' now produce an error
   732 rather than just a warning (in interactive mode);
   733 
   734 
   735 *** HOL ***
   736 
   737 * arith(_tac)
   738 
   739  - Produces a counter example if it cannot prove a goal.
   740    Note that the counter example may be spurious if the goal is not a formula
   741    of quantifier-free linear arithmetic.
   742    In ProofGeneral the counter example appears in the trace buffer.
   743 
   744  - Knows about div k and mod k where k is a numeral of type nat or int.
   745 
   746  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   747    linear arithmetic fails. This takes account of quantifiers and divisibility.
   748    Presburger arithmetic can also be called explicitly via presburger(_tac).
   749 
   750 * simp's arithmetic capabilities have been enhanced a bit: it now
   751 takes ~= in premises into account (by performing a case split);
   752 
   753 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   754 are distributed over a sum of terms;
   755 
   756 * New tactic "trans_tac" and method "trans" instantiate
   757 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   758 "<=", "<" and "=").
   759 
   760 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   761 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   762 
   763 * 'typedef' command has new option "open" to suppress the set
   764 definition;
   765 
   766 * functions Min and Max on finite sets have been introduced (theory
   767 Finite_Set);
   768 
   769 * attribute [symmetric] now works for relations as well; it turns
   770 (x,y) : R^-1 into (y,x) : R, and vice versa;
   771 
   772 * induct over a !!-quantified statement (say !!x1..xn):
   773   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   774 
   775 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   776 %x. None. Warning: empty_def now refers to the previously hidden definition
   777 of the empty set.
   778 
   779 * Algebra: formalization of classical algebra.  Intended as base for
   780 any algebraic development in Isabelle.  Currently covers group theory
   781 (up to Sylow's theorem) and ring theory (Universal Property of
   782 Univariate Polynomials).  Contributions welcome;
   783 
   784 * GroupTheory: deleted, since its material has been moved to Algebra;
   785 
   786 * Complex: new directory of the complex numbers with numeric constants,
   787 nonstandard complex numbers, and some complex analysis, standard and
   788 nonstandard (Jacques Fleuriot);
   789 
   790 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   791 
   792 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   793 Fleuriot);
   794 
   795 * Real/HahnBanach: updated and adapted to locales;
   796 
   797 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   798 Gray and Kramer);
   799 
   800 * UNITY: added the Meier-Sanders theory of progress sets;
   801 
   802 * MicroJava: bytecode verifier and lightweight bytecode verifier
   803 as abstract algorithms, instantiated to the JVM;
   804 
   805 * Bali: Java source language formalization. Type system, operational
   806 semantics, axiomatic semantics. Supported language features:
   807 classes, interfaces, objects,virtual methods, static methods,
   808 static/instance fields, arrays, access modifiers, definite
   809 assignment, exceptions.
   810 
   811 
   812 *** ZF ***
   813 
   814 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   815 universe, etc.);
   816 
   817 * Main ZF: virtually all theories converted to new-style format;
   818 
   819 
   820 *** ML ***
   821 
   822 * Pure: Tactic.prove provides sane interface for internal proofs;
   823 omits the infamous "standard" operation, so this is more appropriate
   824 than prove_goalw_cterm in many situations (e.g. in simprocs);
   825 
   826 * Pure: improved error reporting of simprocs;
   827 
   828 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   829 up simprocs;
   830 
   831 
   832 *** Document preparation ***
   833 
   834 * uses \par instead of \\ for line breaks in theory text. This may
   835 shift some page breaks in large documents. To get the old behaviour
   836 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   837 
   838 * minimized dependencies of isabelle.sty and isabellesym.sty on
   839 other packages
   840 
   841 * \<euro> now needs package babel/greek instead of marvosym (which
   842 broke \Rightarrow)
   843 
   844 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   845 textcomp package)
   846 
   847 
   848 
   849 New in Isabelle2002 (March 2002)
   850 --------------------------------
   851 
   852 *** Document preparation ***
   853 
   854 * greatly simplified document preparation setup, including more
   855 graceful interpretation of isatool usedir -i/-d/-D options, and more
   856 instructive isatool mkdir; users should basically be able to get
   857 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   858 users may run a separate document processing stage manually like this:
   859 "isatool usedir -D output HOL Test && isatool document Test/output";
   860 
   861 * theory dependency graph may now be incorporated into documents;
   862 isatool usedir -g true will produce session_graph.eps/.pdf for use
   863 with \includegraphics of LaTeX;
   864 
   865 * proper spacing of consecutive markup elements, especially text
   866 blocks after section headings;
   867 
   868 * support bold style (for single symbols only), input syntax is like
   869 this: "\<^bold>\<alpha>" or "\<^bold>A";
   870 
   871 * \<bullet> is now output as bold \cdot by default, which looks much
   872 better in printed text;
   873 
   874 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   875 note that these symbols are currently unavailable in Proof General /
   876 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   877 
   878 * isatool latex no longer depends on changed TEXINPUTS, instead
   879 isatool document copies the Isabelle style files to the target
   880 location;
   881 
   882 
   883 *** Isar ***
   884 
   885 * Pure/Provers: improved proof by cases and induction;
   886   - 'case' command admits impromptu naming of parameters (such as
   887     "case (Suc n)");
   888   - 'induct' method divinates rule instantiation from the inductive
   889     claim; no longer requires excessive ?P bindings for proper
   890     instantiation of cases;
   891   - 'induct' method properly enumerates all possibilities of set/type
   892     rules; as a consequence facts may be also passed through *type*
   893     rules without further ado;
   894   - 'induct' method now derives symbolic cases from the *rulified*
   895     rule (before it used to rulify cases stemming from the internal
   896     atomized version); this means that the context of a non-atomic
   897     statement becomes is included in the hypothesis, avoiding the
   898     slightly cumbersome show "PROP ?case" form;
   899   - 'induct' may now use elim-style induction rules without chaining
   900     facts, using ``missing'' premises from the goal state; this allows
   901     rules stemming from inductive sets to be applied in unstructured
   902     scripts, while still benefitting from proper handling of non-atomic
   903     statements; NB: major inductive premises need to be put first, all
   904     the rest of the goal is passed through the induction;
   905   - 'induct' proper support for mutual induction involving non-atomic
   906     rule statements (uses the new concept of simultaneous goals, see
   907     below);
   908   - append all possible rule selections, but only use the first
   909     success (no backtracking);
   910   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   911   - undeclared rule case names default to numbers 1, 2, 3, ...;
   912   - added 'print_induct_rules' (covered by help item in recent Proof
   913     General versions);
   914   - moved induct/cases attributes to Pure, methods to Provers;
   915   - generic method setup instantiated for FOL and HOL;
   916 
   917 * Pure: support multiple simultaneous goal statements, for example
   918 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   919 meta-level mechanism, this acts as if several individual goals had
   920 been stated separately; in particular common proof methods need to be
   921 repeated in order to cover all claims; note that a single elimination
   922 step is *not* sufficient to establish the two conjunctions, so this
   923 fails:
   924 
   925   assume "A & B" then have A and B ..   (*".." fails*)
   926 
   927 better use "obtain" in situations as above; alternative refer to
   928 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   929 
   930 * Pure: proper integration with ``locales''; unlike the original
   931 version by Florian Kammller, Isar locales package high-level proof
   932 contexts rather than raw logical ones (e.g. we admit to include
   933 attributes everywhere); operations on locales include merge and
   934 rename; support for implicit arguments (``structures''); simultaneous
   935 type-inference over imports and text; see also HOL/ex/Locales.thy for
   936 some examples;
   937 
   938 * Pure: the following commands have been ``localized'', supporting a
   939 target locale specification "(in name)": 'lemma', 'theorem',
   940 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   941 stored both within the locale and at the theory level (exported and
   942 qualified by the locale name);
   943 
   944 * Pure: theory goals may now be specified in ``long'' form, with
   945 ad-hoc contexts consisting of arbitrary locale elements. for example
   946 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   947 definitions may be given, too); the result is a meta-level rule with
   948 the context elements being discharged in the obvious way;
   949 
   950 * Pure: new proof command 'using' allows to augment currently used
   951 facts after a goal statement ('using' is syntactically analogous to
   952 'apply', but acts on the goal's facts only); this allows chained facts
   953 to be separated into parts given before and after a claim, as in
   954 ``from a and b have C using d and e <proof>'';
   955 
   956 * Pure: renamed "antecedent" case to "rule_context";
   957 
   958 * Pure: new 'judgment' command records explicit information about the
   959 object-logic embedding (used by several tools internally); no longer
   960 use hard-wired "Trueprop";
   961 
   962 * Pure: added 'corollary' command;
   963 
   964 * Pure: fixed 'token_translation' command;
   965 
   966 * Pure: removed obsolete 'exported' attribute;
   967 
   968 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   969 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   970 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   971 
   972 * Pure: method 'atomize' presents local goal premises as object-level
   973 statements (atomic meta-level propositions); setup controlled via
   974 rewrite rules declarations of 'atomize' attribute; example
   975 application: 'induct' method with proper rule statements in improper
   976 proof *scripts*;
   977 
   978 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   979 now consider the syntactic context of assumptions, giving a better
   980 chance to get type-inference of the arguments right (this is
   981 especially important for locales);
   982 
   983 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   984 mode;
   985 
   986 * Pure/obtain: the formal conclusion "thesis", being marked as
   987 ``internal'', may no longer be reference directly in the text;
   988 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   989 situations;
   990 
   991 * Pure: generic 'sym' attribute which declares a rule both as pure
   992 'elim?' and for the 'symmetric' operation;
   993 
   994 * Pure: marginal comments ``--'' may now occur just anywhere in the
   995 text; the fixed correlation with particular command syntax has been
   996 discontinued;
   997 
   998 * Pure: new method 'rules' is particularly well-suited for proof
   999 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1000 but often produces more compact proof terms with less detours;
  1001 
  1002 * Pure/Provers/classical: simplified integration with pure rule
  1003 attributes and methods; the classical "intro?/elim?/dest?"
  1004 declarations coincide with the pure ones; the "rule" method no longer
  1005 includes classically swapped intros; "intro" and "elim" methods no
  1006 longer pick rules from the context; also got rid of ML declarations
  1007 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1008 INCOMPATIBILITY;
  1009 
  1010 * Provers/classical: attribute 'swapped' produces classical inversions
  1011 of introduction rules;
  1012 
  1013 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1014 rules instead of full simplifier context; 'iff' attribute handles
  1015 conditional rules;
  1016 
  1017 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1018 
  1019 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1020 "(permissive)" option to recover old behavior;
  1021 
  1022 * HOL: 'inductive' no longer features separate (collective) attributes
  1023 for 'intros' (was found too confusing);
  1024 
  1025 * HOL: properly declared induction rules less_induct and
  1026 wf_induct_rule;
  1027 
  1028 
  1029 *** HOL ***
  1030 
  1031 * HOL: moved over to sane numeral syntax; the new policy is as
  1032 follows:
  1033 
  1034   - 0 and 1 are polymorphic constants, which are defined on any
  1035   numeric type (nat, int, real etc.);
  1036 
  1037   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1038   binary representation internally;
  1039 
  1040   - type nat has special constructor Suc, and generally prefers Suc 0
  1041   over 1::nat and Suc (Suc 0) over 2::nat;
  1042 
  1043 This change may cause significant problems of INCOMPATIBILITY; here
  1044 are some hints on converting existing sources:
  1045 
  1046   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1047   entities, so expressions involving "-" (unary or binary minus) need
  1048   to be spaced properly;
  1049 
  1050   - existing occurrences of "1" may need to be constraint "1::nat" or
  1051   even replaced by Suc 0; similar for old "2";
  1052 
  1053   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1054 
  1055   - remove all special provisions on numerals in proofs;
  1056 
  1057 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1058 representation (depends on bin_arith_simps in the default context);
  1059 
  1060 * HOL: symbolic syntax for x^2 (numeral 2);
  1061 
  1062 * HOL: the class of all HOL types is now called "type" rather than
  1063 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1064 in axclass/classes, instance/arities, and (usually rare) occurrences
  1065 in typings (of consts etc.); internally the class is called
  1066 "HOL.type", ML programs should refer to HOLogic.typeS;
  1067 
  1068 * HOL/record package improvements:
  1069   - new derived operations "fields" to build a partial record section,
  1070     "extend" to promote a fixed record to a record scheme, and
  1071     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1072     declared as simp by default;
  1073   - shared operations ("more", "fields", etc.) now need to be always
  1074     qualified) --- potential INCOMPATIBILITY;
  1075   - removed "make_scheme" operations (use "make" with "extend") --
  1076     INCOMPATIBILITY;
  1077   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1078   - provides cases/induct rules for use with corresponding Isar
  1079     methods (for concrete records, record schemes, concrete more
  1080     parts, and schematic more parts -- in that order);
  1081   - internal definitions directly based on a light-weight abstract
  1082     theory of product types over typedef rather than datatype;
  1083 
  1084 * HOL: generic code generator for generating executable ML code from
  1085 specifications; specific support for HOL constructs such as inductive
  1086 datatypes and sets, as well as recursive functions; can be invoked
  1087 via 'generate_code' theory section;
  1088 
  1089 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1090 
  1091 * HOL: consolidated and renamed several theories.  In particular:
  1092         Ord.thy has been absorbed into HOL.thy
  1093         String.thy has been absorbed into List.thy
  1094 
  1095 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1096 (beware of argument permutation!);
  1097 
  1098 * HOL: linorder_less_split superseded by linorder_cases;
  1099 
  1100 * HOL/List: "nodups" renamed to "distinct";
  1101 
  1102 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1103 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1104   - Ex_def has changed, now need to use some_eq_ex
  1105 
  1106 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1107 in this (rare) case use:
  1108 
  1109   delSWrapper "split_all_tac"
  1110   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1111 
  1112 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1113 MAY FAIL;
  1114 
  1115 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1116 Isabelle's type classes, ^ on functions and relations has too general
  1117 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1118 necessary to attach explicit type constraints;
  1119 
  1120 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1121 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1122 renamed accordingly (eg "compI" -> "rel_compI").
  1123 
  1124 * HOL: syntax translations now work properly with numerals and records
  1125 expressions;
  1126 
  1127 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1128 of "lam" -- INCOMPATIBILITY;
  1129 
  1130 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1131 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1132 renamed "Product_Type.unit";
  1133 
  1134 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1135 
  1136 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1137 the "cases" method);
  1138 
  1139 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1140 Florian Kammller);
  1141 
  1142 * HOL/IMP: updated and converted to new-style theory format; several
  1143 parts turned into readable document, with proper Isar proof texts and
  1144 some explanations (by Gerwin Klein);
  1145 
  1146 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1147 
  1148 * HOL-Hyperreal is now a logic image;
  1149 
  1150 
  1151 *** HOLCF ***
  1152 
  1153 * Isar: consts/constdefs supports mixfix syntax for continuous
  1154 operations;
  1155 
  1156 * Isar: domain package adapted to new-style theory format, e.g. see
  1157 HOLCF/ex/Dnat.thy;
  1158 
  1159 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1160 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1161 lift.induct_tac, always use UU instead of Undef;
  1162 
  1163 * HOLCF/IMP: updated and converted to new-style theory;
  1164 
  1165 
  1166 *** ZF ***
  1167 
  1168 * Isar: proper integration of logic-specific tools and packages,
  1169 including theory commands '(co)inductive', '(co)datatype',
  1170 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1171 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1172 
  1173 * theory Main no longer includes AC; for the Axiom of Choice, base
  1174 your theory on Main_ZFC;
  1175 
  1176 * the integer library now covers quotients and remainders, with many
  1177 laws relating division to addition, multiplication, etc.;
  1178 
  1179 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1180 typeless version of the formalism;
  1181 
  1182 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1183 format;
  1184 
  1185 * ZF/Induct: new directory for examples of inductive definitions,
  1186 including theory Multiset for multiset orderings; converted to
  1187 new-style theory format;
  1188 
  1189 * ZF: many new theorems about lists, ordinals, etc.;
  1190 
  1191 
  1192 *** General ***
  1193 
  1194 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1195 variable proof controls level of detail: 0 = no proofs (only oracle
  1196 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1197 also ref manual for further ML interfaces;
  1198 
  1199 * Pure/axclass: removed obsolete ML interface
  1200 goal_subclass/goal_arity;
  1201 
  1202 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1203 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1204 separate tokens, so expressions involving minus need to be spaced
  1205 properly;
  1206 
  1207 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1208 rather than "infixl" or "infixr";
  1209 
  1210 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1211 sort constraint specifications in type inference; e.g. "x::_::foo"
  1212 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1213 type variable);
  1214 
  1215 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1216 control output of nested => (types); the default behavior is
  1217 "type_brackets";
  1218 
  1219 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1220 tokens into AST constants;
  1221 
  1222 * Pure/syntax: prefer later declarations of translations and print
  1223 translation functions; potential INCOMPATIBILITY: need to reverse
  1224 multiple declarations for same syntax element constant;
  1225 
  1226 * Pure/show_hyps reset by default (in accordance to existing Isar
  1227 practice);
  1228 
  1229 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1230 addSafter;
  1231 
  1232 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1233 as well;
  1234 
  1235 * system: tested support for MacOS X; should be able to get Isabelle +
  1236 Proof General to work in a plain Terminal after installing Poly/ML
  1237 (e.g. from the Isabelle distribution area) and GNU bash alone
  1238 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1239 support requires further installations, e.g. from
  1240 http://fink.sourceforge.net/);
  1241 
  1242 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1243 
  1244 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1245 of 40 MB), cf. ML_OPTIONS;
  1246 
  1247 * system: Proof General keywords specification is now part of the
  1248 Isabelle distribution (see etc/isar-keywords.el);
  1249 
  1250 * system: support for persistent Proof General sessions (refrain from
  1251 outdating all loaded theories on startup); user may create writable
  1252 logic images like this: ``isabelle -q HOL Test'';
  1253 
  1254 * system: smart selection of Isabelle process versus Isabelle
  1255 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1256 run both "isabelle" and "Isabelle" even if file names are badly
  1257 damaged (executable inspects the case of the first letter of its own
  1258 name); added separate "isabelle-process" and "isabelle-interface";
  1259 
  1260 * system: refrain from any attempt at filtering input streams; no
  1261 longer support ``8bit'' encoding of old isabelle font, instead proper
  1262 iso-latin characters may now be used; the related isatools
  1263 "symbolinput" and "nonascii" have disappeared as well;
  1264 
  1265 * system: removed old "xterm" interface (the print modes "xterm" and
  1266 "xterm_color" are still available for direct use in a suitable
  1267 terminal);
  1268 
  1269 
  1270 
  1271 New in Isabelle99-2 (February 2001)
  1272 -----------------------------------
  1273 
  1274 *** Overview of INCOMPATIBILITIES ***
  1275 
  1276 * HOL: please note that theories in the Library and elsewhere often use the
  1277 new-style (Isar) format; to refer to their theorems in an ML script you must
  1278 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1279 
  1280 * HOL: inductive package no longer splits induction rule aggressively,
  1281 but only as far as specified by the introductions given; the old
  1282 format may be recovered via ML function complete_split_rule or attribute
  1283 'split_rule (complete)';
  1284 
  1285 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1286 gfp_Tarski to gfp_unfold;
  1287 
  1288 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1289 
  1290 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1291 relation); infix "^^" has been renamed "``"; infix "``" has been
  1292 renamed "`"; "univalent" has been renamed "single_valued";
  1293 
  1294 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1295 operation;
  1296 
  1297 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1298 
  1299 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1300 
  1301 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1302 consequence, it is no longer monotonic wrt. the local goal context
  1303 (which is now passed through the inductive cases);
  1304 
  1305 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1306 \<gg> to \<ggreater>;
  1307 
  1308 
  1309 *** Document preparation ***
  1310 
  1311 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1312 available: are "it" for near math-mode best-style output, "sl" for
  1313 slanted text style, and "tt" for plain type-writer; if no
  1314 \isabellestyle command is given, output is according to slanted
  1315 type-writer);
  1316 
  1317 * support sub/super scripts (for single symbols only), input syntax is
  1318 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1319 
  1320 * some more standard symbols; see Appendix A of the system manual for
  1321 the complete list of symbols defined in isabellesym.sty;
  1322 
  1323 * improved isabelle style files; more abstract symbol implementation
  1324 (should now use \isamath{...} and \isatext{...} in custom symbol
  1325 definitions);
  1326 
  1327 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1328 state; Note that presentation of goal states does not conform to
  1329 actual human-readable proof documents.  Please do not include goal
  1330 states into document output unless you really know what you are doing!
  1331 
  1332 * proper indentation of antiquoted output with proportional LaTeX
  1333 fonts;
  1334 
  1335 * no_document ML operator temporarily disables LaTeX document
  1336 generation;
  1337 
  1338 * isatool unsymbolize tunes sources for plain ASCII communication;
  1339 
  1340 
  1341 *** Isar ***
  1342 
  1343 * Pure: Isar now suffers initial goal statements to contain unbound
  1344 schematic variables (this does not conform to actual readable proof
  1345 documents, due to unpredictable outcome and non-compositional proof
  1346 checking); users who know what they are doing may use schematic goals
  1347 for Prolog-style synthesis of proven results;
  1348 
  1349 * Pure: assumption method (an implicit finishing) now handles actual
  1350 rules as well;
  1351 
  1352 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1353 initial goal, declare "that" only as Pure intro (only for single
  1354 steps); the "that" rule assumption may now be involved in implicit
  1355 finishing, thus ".." becomes a feasible for trivial obtains;
  1356 
  1357 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1358 instance proofs may be performed by "..";
  1359 
  1360 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1361 statements as well;
  1362 
  1363 * Pure: more robust selection of calculational rules;
  1364 
  1365 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1366 rule (as well as the assumption rule);
  1367 
  1368 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1369 lemmas, using the graph browser tool;
  1370 
  1371 * Pure: predict failure of "show" in interactive mode;
  1372 
  1373 * Pure: 'thms_containing' now takes actual terms as arguments;
  1374 
  1375 * HOL: improved method 'induct' --- now handles non-atomic goals
  1376 (potential INCOMPATIBILITY); tuned error handling;
  1377 
  1378 * HOL: cases and induct rules now provide explicit hints about the
  1379 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1380 any remaining facts are inserted into the goal verbatim;
  1381 
  1382 * HOL: local contexts (aka cases) may now contain term bindings as
  1383 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1384 the result to be shown in each case;
  1385 
  1386 * HOL: added 'recdef_tc' command;
  1387 
  1388 * isatool convert assists in eliminating legacy ML scripts;
  1389 
  1390 
  1391 *** HOL ***
  1392 
  1393 * HOL/Library: a collection of generic theories to be used together
  1394 with main HOL; the theory loader path already includes this directory
  1395 by default; the following existing theories have been moved here:
  1396 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1397 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1398 
  1399 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1400 modelling and verification task performed in Isabelle/HOL +
  1401 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1402 
  1403 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1404 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1405 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1406 'domain', this makes the theory consistent with mathematical
  1407 literature;
  1408 
  1409 * HOL basics: added overloaded operations "inverse" and "divide"
  1410 (infix "/"), syntax for generic "abs" operation, generic summation
  1411 operator \<Sum>;
  1412 
  1413 * HOL/typedef: simplified package, provide more useful rules (see also
  1414 HOL/subset.thy);
  1415 
  1416 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1417 now expressed as a proper nested rule (old-style tactic scripts may
  1418 require atomize_strip_tac to cope with non-atomic premises);
  1419 
  1420 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1421 to "split_conv" (old name still available for compatibility);
  1422 
  1423 * HOL: improved concrete syntax for strings (e.g. allows translation
  1424 rules with string literals);
  1425 
  1426 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1427  and Fleuriot's mechanization of analysis, including the transcendental
  1428  functions for the reals;
  1429 
  1430 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1431 
  1432 
  1433 *** CTT ***
  1434 
  1435 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1436 "lam" is displayed as TWO lambda-symbols
  1437 
  1438 * CTT: theory Main now available, containing everything (that is, Bool
  1439 and Arith);
  1440 
  1441 
  1442 *** General ***
  1443 
  1444 * Pure: the Simplifier has been implemented properly as a derived rule
  1445 outside of the actual kernel (at last!); the overall performance
  1446 penalty in practical applications is about 50%, while reliability of
  1447 the Isabelle inference kernel has been greatly improved;
  1448 
  1449 * print modes "brackets" and "no_brackets" control output of nested =>
  1450 (types) and ==> (props); the default behaviour is "brackets";
  1451 
  1452 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1453 as assumptions as well;
  1454 
  1455 * system: support Poly/ML 4.0;
  1456 
  1457 * system: isatool install handles KDE version 1 or 2;
  1458 
  1459 
  1460 
  1461 New in Isabelle99-1 (October 2000)
  1462 ----------------------------------
  1463 
  1464 *** Overview of INCOMPATIBILITIES ***
  1465 
  1466 * HOL: simplification of natural numbers is much changed; to partly
  1467 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1468 issue the following ML commands:
  1469 
  1470   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1471   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1472 
  1473 * HOL: simplification no longer dives into case-expressions; this is
  1474 controlled by "t.weak_case_cong" for each datatype t;
  1475 
  1476 * HOL: nat_less_induct renamed to less_induct;
  1477 
  1478 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1479 fixsome to patch .thy and .ML sources automatically;
  1480 
  1481   select_equality  -> some_equality
  1482   select_eq_Ex     -> some_eq_ex
  1483   selectI2EX       -> someI2_ex
  1484   selectI2         -> someI2
  1485   selectI          -> someI
  1486   select1_equality -> some1_equality
  1487   Eps_sym_eq       -> some_sym_eq_trivial
  1488   Eps_eq           -> some_eq_trivial
  1489 
  1490 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1491 
  1492 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1493 instead);
  1494 
  1495 * HOL: the recursion equations generated by 'recdef' are now called
  1496 f.simps instead of f.rules;
  1497 
  1498 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1499 
  1500 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1501 sometimes be needed;
  1502 
  1503 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1504 
  1505 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1506 
  1507 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1508 product is now "<*>" instead of "Times"; the lexicographic product is
  1509 now "<*lex*>" instead of "**";
  1510 
  1511 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1512 of main HOL, but was unused); better use HOL's datatype package;
  1513 
  1514 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1515 the old syntax may be recovered as follows:
  1516 
  1517   syntax (symbols)
  1518     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1519       (infixl "\\<oplus>" 100)
  1520 
  1521 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1522 
  1523 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1524 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1525 internally;
  1526 
  1527 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1528 changed from A/r to A//r;
  1529 
  1530 * ZF: new treatment of arithmetic (nat & int) may break some old
  1531 proofs;
  1532 
  1533 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1534 rulify -> rule_format, elimify -> elim_format, ...);
  1535 
  1536 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1537 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1538 should have to change intro!! to intro? only); replaced "delrule" by
  1539 "rule del";
  1540 
  1541 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1542 
  1543 * Provers: strengthened force_tac by using new first_best_tac;
  1544 
  1545 * LaTeX document preparation: several changes of isabelle.sty (see
  1546 lib/texinputs);
  1547 
  1548 
  1549 *** Document preparation ***
  1550 
  1551 * formal comments (text blocks etc.) in new-style theories may now
  1552 contain antiquotations of thm/prop/term/typ/text to be presented
  1553 according to latex print mode; concrete syntax is like this:
  1554 @{term[show_types] "f(x) = a + x"};
  1555 
  1556 * isatool mkdir provides easy setup of Isabelle session directories,
  1557 including proper document sources;
  1558 
  1559 * generated LaTeX sources are now deleted after successful run
  1560 (isatool document -c); may retain a copy somewhere else via -D option
  1561 of isatool usedir;
  1562 
  1563 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1564 style files, achieving self-contained LaTeX sources and simplifying
  1565 LaTeX debugging;
  1566 
  1567 * old-style theories now produce (crude) LaTeX output as well;
  1568 
  1569 * browser info session directories are now self-contained (may be put
  1570 on WWW server seperately); improved graphs of nested sessions; removed
  1571 graph for 'all sessions';
  1572 
  1573 * several improvements in isabelle style files; \isabellestyle{it}
  1574 produces fake math mode output; \isamarkupheader is now \section by
  1575 default; see lib/texinputs/isabelle.sty etc.;
  1576 
  1577 
  1578 *** Isar ***
  1579 
  1580 * Isar/Pure: local results and corresponding term bindings are now
  1581 subject to Hindley-Milner polymorphism (similar to ML); this
  1582 accommodates incremental type-inference very nicely;
  1583 
  1584 * Isar/Pure: new derived language element 'obtain' supports
  1585 generalized existence reasoning;
  1586 
  1587 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1588 support accumulation of results, without applying any rules yet;
  1589 useful to collect intermediate results without explicit name
  1590 references, and for use with transitivity rules with more than 2
  1591 premises;
  1592 
  1593 * Isar/Pure: scalable support for case-analysis type proofs: new
  1594 'case' language element refers to local contexts symbolically, as
  1595 produced by certain proof methods; internally, case names are attached
  1596 to theorems as "tags";
  1597 
  1598 * Isar/Pure: theory command 'hide' removes declarations from
  1599 class/type/const name spaces;
  1600 
  1601 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1602 indicate potential overloading;
  1603 
  1604 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1605 
  1606 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1607 "{a,b,c}" instead of {a,b,c};
  1608 
  1609 * Isar/Pure now provides its own version of intro/elim/dest
  1610 attributes; useful for building new logics, but beware of confusion
  1611 with the version in Provers/classical;
  1612 
  1613 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1614 case name 'antecedent';
  1615 
  1616 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1617 to the current context is now done automatically);
  1618 
  1619 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1620 for definining proof methods in ML;
  1621 
  1622 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1623 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1624 most cases, one should have to change intro!! to intro? only);
  1625 replaced "delrule" by "rule del";
  1626 
  1627 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1628 'symmetric' attribute (the latter supercedes [RS sym]);
  1629 
  1630 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1631 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1632 well (including splits);
  1633 
  1634 * Isar/Provers: Simplifier and Classical methods now support all kind
  1635 of modifiers used in the past, including 'cong', 'iff', etc.
  1636 
  1637 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1638 of Simplifier and Classical reasoner);
  1639 
  1640 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1641 now support named cases; major packages (inductive, datatype, primrec,
  1642 recdef) support case names and properly name parameters;
  1643 
  1644 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1645 monotonicity conditions are extracted to be proven at end of
  1646 calculations;
  1647 
  1648 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1649 method anyway;
  1650 
  1651 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1652 split_if split_if_asm; datatype package provides theorems foo.splits =
  1653 foo.split foo.split_asm for each datatype;
  1654 
  1655 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1656 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1657 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1658 use "(cases (simplified))" method in proper proof texts);
  1659 
  1660 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1661 
  1662 * Isar: names of theorems etc. may be natural numbers as well;
  1663 
  1664 * Isar: 'pr' command: optional arguments for goals_limit and
  1665 ProofContext.prems_limit; no longer prints theory contexts, but only
  1666 proof states;
  1667 
  1668 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1669 additional print modes to be specified; e.g. "pr(latex)" will print
  1670 proof state according to the Isabelle LaTeX style;
  1671 
  1672 * Isar: improved support for emulating tactic scripts, including proof
  1673 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1674 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1675 (for HOL datatypes);
  1676 
  1677 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1678 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1679 'proof method scripts' have to be in depth-first order;
  1680 
  1681 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1682 
  1683 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1684 should instead use individual commands for printing items
  1685 (print_commands, print_methods etc.);
  1686 
  1687 * Isar: added 'nothing' --- the empty list of theorems;
  1688 
  1689 
  1690 *** HOL ***
  1691 
  1692 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1693 corresponding virtual machine and a specification of its bytecode
  1694 verifier and a lightweight bytecode verifier, including proofs of
  1695 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1696 Cornelia Pusch (see also the homepage of project Bali at
  1697 http://isabelle.in.tum.de/Bali/);
  1698 
  1699 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1700 Clemens Ballarin;
  1701 
  1702 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1703 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1704 Rasmussen;
  1705 
  1706 * HOL/Lattice: fundamental concepts of lattice theory and order
  1707 structures, including duals, properties of bounds versus algebraic
  1708 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1709 Theorem for complete lattices etc.; may also serve as a demonstration
  1710 for abstract algebraic reasoning using axiomatic type classes, and
  1711 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1712 
  1713 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1714 von Oheimb;
  1715 
  1716 * HOL/IMPP: extension of IMP with local variables and mutually
  1717 recursive procedures, by David von Oheimb;
  1718 
  1719 * HOL/Lambda: converted into new-style theory and document;
  1720 
  1721 * HOL/ex/Multiquote: example of multiple nested quotations and
  1722 anti-quotations -- basically a generalized version of de-Bruijn
  1723 representation; very useful in avoiding lifting of operations;
  1724 
  1725 * HOL/record: added general record equality rule to simpset; fixed
  1726 select-update simplification procedure to handle extended records as
  1727 well; admit "r" as field name;
  1728 
  1729 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1730 other numeric types and also as the identity of groups, rings, etc.;
  1731 
  1732 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1733 Types nat and int belong to this axclass;
  1734 
  1735 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1736    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1737    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1738   two terms #m*u and #n*u are replaced by #(m+n)*u
  1739     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1740   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1741     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1742 
  1743 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1744 powerful prover for predicate logic but knows nothing of clasets; see
  1745 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1746 
  1747 * HOL: new version of "case_tac" subsumes both boolean case split and
  1748 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1749 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1750 
  1751 * HOL: simplification no longer dives into case-expressions: only the
  1752 selector expression is simplified, but not the remaining arms; to
  1753 enable full simplification of case-expressions for datatype t, you may
  1754 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1755 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1756 
  1757 * HOL/recdef: the recursion equations generated by 'recdef' for
  1758 function 'f' are now called f.simps instead of f.rules; if all
  1759 termination conditions are proved automatically, these simplification
  1760 rules are added to the simpset, as in primrec; rules may be named
  1761 individually as well, resulting in a separate list of theorems for
  1762 each equation;
  1763 
  1764 * HOL/While is a new theory that provides a while-combinator. It
  1765 permits the definition of tail-recursive functions without the
  1766 provision of a termination measure. The latter is necessary once the
  1767 invariant proof rule for while is applied.
  1768 
  1769 * HOL: new (overloaded) notation for the set of elements below/above
  1770 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1771 
  1772 * HOL: theorems impI, allI, ballI bound as "strip";
  1773 
  1774 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1775 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1776 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1777 
  1778 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1779 
  1780 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1781 main HOL, but was unused);
  1782 
  1783 * HOL: fewer consts declared as global (e.g. have to refer to
  1784 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1785 
  1786 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1787 in case of overlap with user translations (e.g. judgements over
  1788 tuples); (note that the underlying logical represenation is still
  1789 bogus);
  1790 
  1791 
  1792 *** ZF ***
  1793 
  1794 * ZF: simplification automatically cancels common terms in arithmetic
  1795 expressions over nat and int;
  1796 
  1797 * ZF: new treatment of nat to minimize type-checking: all operators
  1798 coerce their operands to a natural number using the function natify,
  1799 making the algebraic laws unconditional;
  1800 
  1801 * ZF: as above, for int: operators coerce their operands to an integer
  1802 using the function intify;
  1803 
  1804 * ZF: the integer library now contains many of the usual laws for the
  1805 orderings, including $<=, and monotonicity laws for $+ and $*;
  1806 
  1807 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1808 simplification;
  1809 
  1810 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1811 to the simplifier and classical reasoner simultaneously;
  1812 
  1813 
  1814 *** General ***
  1815 
  1816 * Provers: blast_tac now handles actual object-logic rules as
  1817 assumptions; note that auto_tac uses blast_tac internally as well;
  1818 
  1819 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1820 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1821 
  1822 * Provers: delrules now handles destruct rules as well (no longer need
  1823 explicit make_elim);
  1824 
  1825 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1826   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1827 use instead the strong form,
  1828   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1829 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1830 from destruct-rules;
  1831 
  1832 * Provers: Simplifier.easy_setup provides a fast path to basic
  1833 Simplifier setup for new object-logics;
  1834 
  1835 * Pure: AST translation rules no longer require constant head on LHS;
  1836 
  1837 * Pure: improved name spaces: ambiguous output is qualified; support
  1838 for hiding of names;
  1839 
  1840 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1841 XSYMBOL_HOME; no longer need to do manual configuration in most
  1842 situations;
  1843 
  1844 * system: compression of ML heaps images may now be controlled via -c
  1845 option of isabelle and isatool usedir (currently only observed by
  1846 Poly/ML);
  1847 
  1848 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1849 useful for remote X11);
  1850 
  1851 * system: provide TAGS file for Isabelle sources;
  1852 
  1853 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1854 order;
  1855 
  1856 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1857 timing flag supersedes proof_timing and Toplevel.trace;
  1858 
  1859 * ML: new combinators |>> and |>>> for incremental transformations
  1860 with secondary results (e.g. certain theory extensions):
  1861 
  1862 * ML: PureThy.add_defs gets additional argument to indicate potential
  1863 overloading (usually false);
  1864 
  1865 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1866 results;
  1867 
  1868 
  1869 
  1870 New in Isabelle99 (October 1999)
  1871 --------------------------------
  1872 
  1873 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1874 
  1875 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1876 are no longer simplified.  (This allows the simplifier to unfold recursive
  1877 functional programs.)  To restore the old behaviour, declare
  1878 
  1879     Delcongs [if_weak_cong];
  1880 
  1881 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1882 complement;
  1883 
  1884 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1885 
  1886 * HOL/datatype: mutual_induct_tac no longer exists --
  1887   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1888 
  1889 * HOL/typedef: fixed type inference for representing set; type
  1890 arguments now have to occur explicitly on the rhs as type constraints;
  1891 
  1892 * ZF: The con_defs part of an inductive definition may no longer refer
  1893 to constants declared in the same theory;
  1894 
  1895 * HOL, ZF: the function mk_cases, generated by the inductive
  1896 definition package, has lost an argument.  To simplify its result, it
  1897 uses the default simpset instead of a supplied list of theorems.
  1898 
  1899 * HOL/List: the constructors of type list are now Nil and Cons;
  1900 
  1901 * Simplifier: the type of the infix ML functions
  1902         setSSolver addSSolver setSolver addSolver
  1903 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1904 for packaging solvers. A solver is created via
  1905         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1906 where the string argument is only a comment.
  1907 
  1908 
  1909 *** Proof tools ***
  1910 
  1911 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1912 decision procedure for linear arithmetic. Currently it is used for
  1913 types `nat', `int', and `real' in HOL (see below); it can, should and
  1914 will be instantiated for other types and logics as well.
  1915 
  1916 * The simplifier now accepts rewrite rules with flexible heads, eg
  1917      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1918   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1919   matching.
  1920 
  1921 
  1922 *** General ***
  1923 
  1924 * New Isabelle/Isar subsystem provides an alternative to traditional
  1925 tactical theorem proving; together with the ProofGeneral/isar user
  1926 interface it offers an interactive environment for developing human
  1927 readable proof documents (Isar == Intelligible semi-automated
  1928 reasoning); for further information see isatool doc isar-ref,
  1929 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1930 
  1931 * improved and simplified presentation of theories: better HTML markup
  1932 (including colors), graph views in several sizes; isatool usedir now
  1933 provides a proper interface for user theories (via -P option); actual
  1934 document preparation based on (PDF)LaTeX is available as well (for
  1935 new-style theories only); see isatool doc system for more information;
  1936 
  1937 * native support for Proof General, both for classic Isabelle and
  1938 Isabelle/Isar;
  1939 
  1940 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1941 using the graph browser tool;
  1942 
  1943 * Isabelle manuals now also available as PDF;
  1944 
  1945 * theory loader rewritten from scratch (may not be fully
  1946 bug-compatible); old loadpath variable has been replaced by show_path,
  1947 add_path, del_path, reset_path functions; new operations such as
  1948 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1949 isatool doc ref);
  1950 
  1951 * improved isatool install: option -k creates KDE application icon,
  1952 option -p DIR installs standalone binaries;
  1953 
  1954 * added ML_PLATFORM setting (useful for cross-platform installations);
  1955 more robust handling of platform specific ML images for SML/NJ;
  1956 
  1957 * the settings environment is now statically scoped, i.e. it is never
  1958 created again in sub-processes invoked from isabelle, isatool, or
  1959 Isabelle;
  1960 
  1961 * path element specification '~~' refers to '$ISABELLE_HOME';
  1962 
  1963 * in locales, the "assumes" and "defines" parts may be omitted if
  1964 empty;
  1965 
  1966 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1967 long arrows);
  1968 
  1969 * new print_mode "HTML";
  1970 
  1971 * new flag show_tags controls display of tags of theorems (which are
  1972 basically just comments that may be attached by some tools);
  1973 
  1974 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1975 mode and goal output format:
  1976 
  1977 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1978 244c244
  1979 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1980 ---
  1981 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1982 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1983 181c181
  1984 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1985 ---
  1986 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1987 
  1988 * function bind_thms stores lists of theorems (cf. bind_thm);
  1989 
  1990 * new shorthand tactics ftac, eatac, datac, fatac;
  1991 
  1992 * qed (and friends) now accept "" as result name; in that case the
  1993 theorem is not stored, but proper checks and presentation of the
  1994 result still apply;
  1995 
  1996 * theorem database now also indexes constants "Trueprop", "all",
  1997 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  1998 
  1999 
  2000 *** HOL ***
  2001 
  2002 ** HOL arithmetic **
  2003 
  2004 * There are now decision procedures for linear arithmetic over nat and
  2005 int:
  2006 
  2007 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2008 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2009 are treated as atomic; subformulae not involving type `nat' or `int'
  2010 are ignored; quantified subformulae are ignored unless they are
  2011 positive universal or negative existential. The tactic has to be
  2012 invoked by hand and can be a little bit slow. In particular, the
  2013 running time is exponential in the number of occurrences of `min' and
  2014 `max', and `-' on `nat'.
  2015 
  2016 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2017 (negated) (in)equalities among the premises and the conclusion into
  2018 account (i.e. no compound formulae) and does not know about `min' and
  2019 `max', and `-' on `nat'. It is fast and is used automatically by the
  2020 simplifier.
  2021 
  2022 NB: At the moment, these decision procedures do not cope with mixed
  2023 nat/int formulae where the two parts interact, such as `m < n ==>
  2024 int(m) < int(n)'.
  2025 
  2026 * HOL/Numeral provides a generic theory of numerals (encoded
  2027 efficiently as bit strings); setup for types nat/int/real is in place;
  2028 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2029 int, existing theories and proof scripts may require a few additional
  2030 type constraints;
  2031 
  2032 * integer division and remainder can now be performed on constant
  2033 arguments;
  2034 
  2035 * many properties of integer multiplication, division and remainder
  2036 are now available;
  2037 
  2038 * An interface to the Stanford Validity Checker (SVC) is available through the
  2039 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2040 are proved automatically.  SVC must be installed separately, and its results
  2041 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2042 invocation of the underlying oracle).  For SVC see
  2043   http://verify.stanford.edu/SVC
  2044 
  2045 * IsaMakefile: the HOL-Real target now builds an actual image;
  2046 
  2047 
  2048 ** HOL misc **
  2049 
  2050 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2051 (in Isabelle/Isar) -- by Gertrud Bauer;
  2052 
  2053 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2054 analysis for assembly languages with subtypes;
  2055 
  2056 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2057 -- avoids syntactic ambiguities and treats state, transition, and
  2058 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2059 changed syntax and (many) tactics;
  2060 
  2061 * HOL/inductive: Now also handles more general introduction rules such
  2062   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2063   theorems are now maintained within the theory (maintained via the
  2064   "mono" attribute);
  2065 
  2066 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2067   (using function types) such as
  2068 
  2069   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2070 
  2071 * HOL/record: record_simproc (part of the default simpset) takes care
  2072 of selectors applied to updated records; record_split_tac is no longer
  2073 part of the default claset; update_defs may now be removed from the
  2074 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2075 
  2076   claset_ref () := claset() addSWrapper record_split_wrapper;
  2077   Delsimprocs [record_simproc]
  2078 
  2079 * HOL/typedef: fixed type inference for representing set; type
  2080 arguments now have to occur explicitly on the rhs as type constraints;
  2081 
  2082 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2083 names rather than an ML expression;
  2084 
  2085 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2086 supplied later.  Program schemes can be defined, such as
  2087     "While B C s = (if B s then While B C (C s) else s)"
  2088 where the well-founded relation can be chosen after B and C have been given.
  2089 
  2090 * HOL/List: the constructors of type list are now Nil and Cons;
  2091 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2092 course, ML tools referring to List.list.op # etc. have to be adapted;
  2093 
  2094 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2095 disabled by default; run isabelle with option -m HOL to get back to
  2096 the original Gordon/HOL-style output;
  2097 
  2098 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2099 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2100 
  2101 * HOL basic syntax simplified (more orthogonal): all variants of
  2102 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2103 Eps operator is provided as well: "SOME x. P[x]";
  2104 
  2105 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2106 
  2107 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2108 thus available for user theories;
  2109 
  2110 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2111 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2112 time;
  2113 
  2114 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2115 several times and then mp;
  2116 
  2117 
  2118 *** LK ***
  2119 
  2120 * the notation <<...>> is now available as a notation for sequences of
  2121 formulas;
  2122 
  2123 * the simplifier is now installed
  2124 
  2125 * the axiom system has been generalized (thanks to Soren Heilmann)
  2126 
  2127 * the classical reasoner now has a default rule database
  2128 
  2129 
  2130 *** ZF ***
  2131 
  2132 * new primrec section allows primitive recursive functions to be given
  2133 directly (as in HOL) over datatypes and the natural numbers;
  2134 
  2135 * new tactics induct_tac and exhaust_tac for induction (or case
  2136 analysis) over datatypes and the natural numbers;
  2137 
  2138 * the datatype declaration of type T now defines the recursor T_rec;
  2139 
  2140 * simplification automatically does freeness reasoning for datatype
  2141 constructors;
  2142 
  2143 * automatic type-inference, with AddTCs command to insert new
  2144 type-checking rules;
  2145 
  2146 * datatype introduction rules are now added as Safe Introduction rules
  2147 to the claset;
  2148 
  2149 * the syntax "if P then x else y" is now available in addition to
  2150 if(P,x,y);
  2151 
  2152 
  2153 *** Internal programming interfaces ***
  2154 
  2155 * tuned simplifier trace output; new flag debug_simp;
  2156 
  2157 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2158 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2159 
  2160 * AxClass.axclass_tac lost the theory argument;
  2161 
  2162 * tuned current_goals_markers semantics: begin / end goal avoids
  2163 printing empty lines;
  2164 
  2165 * removed prs and prs_fn hook, which was broken because it did not
  2166 include \n in its semantics, forcing writeln to add one
  2167 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2168 string -> unit if you really want to output text without newline;
  2169 
  2170 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2171 plain output, interface builders may have to enable 'isabelle_font'
  2172 mode to get Isabelle font glyphs as before;
  2173 
  2174 * refined token_translation interface; INCOMPATIBILITY: output length
  2175 now of type real instead of int;
  2176 
  2177 * theory loader actions may be traced via new ThyInfo.add_hook
  2178 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2179 your own database of information attached to *whole* theories -- as
  2180 opposed to intra-theory data slots offered via TheoryDataFun;
  2181 
  2182 * proper handling of dangling sort hypotheses (at last!);
  2183 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2184 extra sort hypotheses that can be witnessed from the type signature;
  2185 the force_strip_shyps flag is gone, any remaining shyps are simply
  2186 left in the theorem (with a warning issued by strip_shyps_warning);
  2187 
  2188 
  2189 
  2190 New in Isabelle98-1 (October 1998)
  2191 ----------------------------------
  2192 
  2193 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2194 
  2195 * several changes of automated proof tools;
  2196 
  2197 * HOL: major changes to the inductive and datatype packages, including
  2198 some minor incompatibilities of theory syntax;
  2199 
  2200 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2201 called `inj_on';
  2202 
  2203 * HOL: removed duplicate thms in Arith:
  2204   less_imp_add_less  should be replaced by  trans_less_add1
  2205   le_imp_add_le      should be replaced by  trans_le_add1
  2206 
  2207 * HOL: unary minus is now overloaded (new type constraints may be
  2208 required);
  2209 
  2210 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2211 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2212 now taken as an integer constant.
  2213 
  2214 * Pure: ML function 'theory_of' renamed to 'theory';
  2215 
  2216 
  2217 *** Proof tools ***
  2218 
  2219 * Simplifier:
  2220   1. Asm_full_simp_tac is now more aggressive.
  2221      1. It will sometimes reorient premises if that increases their power to
  2222         simplify.
  2223      2. It does no longer proceed strictly from left to right but may also
  2224         rotate premises to achieve further simplification.
  2225      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2226      old Asm_full_simp_tac in that it does not rotate premises.
  2227   2. The simplifier now knows a little bit about nat-arithmetic.
  2228 
  2229 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2230 allows for selected deletion of wrappers, by introduction of names for
  2231 wrapper functionals.  This implies that addbefore, addSbefore,
  2232 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2233 and that adding two tactics with the same name overwrites the first
  2234 one (emitting a warning).
  2235   type wrapper = (int -> tactic) -> (int -> tactic)
  2236   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2237   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2238   delWrapper, delSWrapper: claset *  string            -> claset
  2239   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2240 
  2241 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2242 semantics; addbefore now affects only the unsafe part of step_tac
  2243 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2244 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2245 by Force_tac;
  2246 
  2247 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2248 compWrapper; added safe wrapper (and access functions for it);
  2249 
  2250 * HOL/split_all_tac is now much faster and fails if there is nothing
  2251 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2252 and the names of the automatically generated variables have changed.
  2253 split_all_tac has moved within claset() from unsafe wrappers to safe
  2254 wrappers, which means that !!-bound variables are split much more
  2255 aggressively, and safe_tac and clarify_tac now split such variables.
  2256 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2257 Note: the same holds for record_split_tac, which does the job of
  2258 split_all_tac for record fields.
  2259 
  2260 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2261 permanently to the default simpset using Addsplits just like
  2262 Addsimps. They can be removed via Delsplits just like
  2263 Delsimps. Lower-case versions are also available.
  2264 
  2265 * HOL/Simplifier: The rule split_if is now part of the default
  2266 simpset. This means that the simplifier will eliminate all occurrences
  2267 of if-then-else in the conclusion of a goal. To prevent this, you can
  2268 either remove split_if completely from the default simpset by
  2269 `Delsplits [split_if]' or remove it in a specific call of the
  2270 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2271 other case splitting rules to/from the default simpset: every datatype
  2272 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2273 t is the name of the datatype).
  2274 
  2275 * Classical reasoner / Simplifier combination: new force_tac (and
  2276 derivatives Force_tac, force) combines rewriting and classical
  2277 reasoning (and whatever other tools) similarly to auto_tac, but is
  2278 aimed to solve the given subgoal completely.
  2279 
  2280 
  2281 *** General ***
  2282 
  2283 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2284 and `goalw': the theory is no longer needed as an explicit argument -
  2285 the current theory context is used; assumptions are no longer returned
  2286 at the ML-level unless one of them starts with ==> or !!; it is
  2287 recommended to convert to these new commands using isatool fixgoal
  2288 (backup your sources first!);
  2289 
  2290 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2291 the current theory context, and 'theory' to lookup stored theories;
  2292 
  2293 * new theory section 'locale' for declaring constants, assumptions and
  2294 definitions that have local scope;
  2295 
  2296 * new theory section 'nonterminals' for purely syntactic types;
  2297 
  2298 * new theory section 'setup' for generic ML setup functions
  2299 (e.g. package initialization);
  2300 
  2301 * the distribution now includes Isabelle icons: see
  2302 lib/logo/isabelle-{small,tiny}.xpm;
  2303 
  2304 * isatool install - install binaries with absolute references to
  2305 ISABELLE_HOME/bin;
  2306 
  2307 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2308 
  2309 * print mode 'emacs' reserved for Isamode;
  2310 
  2311 * support multiple print (ast) translations per constant name;
  2312 
  2313 * theorems involving oracles are now printed with a suffixed [!];
  2314 
  2315 
  2316 *** HOL ***
  2317 
  2318 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2319 
  2320 * HOL/inductive package reorganized and improved: now supports mutual
  2321 definitions such as
  2322 
  2323   inductive EVEN ODD
  2324     intrs
  2325       null "0 : EVEN"
  2326       oddI "n : EVEN ==> Suc n : ODD"
  2327       evenI "n : ODD ==> Suc n : EVEN"
  2328 
  2329 new theorem list "elims" contains an elimination rule for each of the
  2330 recursive sets; inductive definitions now handle disjunctive premises
  2331 correctly (also ZF);
  2332 
  2333 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2334 "mutual_induct" no longer exists - the induction rule is always
  2335 contained in "induct";
  2336 
  2337 
  2338 * HOL/datatype package re-implemented and greatly improved: now
  2339 supports mutually recursive datatypes such as
  2340 
  2341   datatype
  2342     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2343             | SUM ('a aexp) ('a aexp)
  2344             | DIFF ('a aexp) ('a aexp)
  2345             | NUM 'a
  2346   and
  2347     'a bexp = LESS ('a aexp) ('a aexp)
  2348             | AND ('a bexp) ('a bexp)
  2349             | OR ('a bexp) ('a bexp)
  2350 
  2351 as well as indirectly recursive datatypes such as
  2352 
  2353   datatype
  2354     ('a, 'b) term = Var 'a
  2355                   | App 'b ((('a, 'b) term) list)
  2356 
  2357 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2358 induction on mutually / indirectly recursive datatypes.
  2359 
  2360 Primrec equations are now stored in theory and can be accessed via
  2361 <function_name>.simps.
  2362 
  2363 INCOMPATIBILITIES:
  2364 
  2365   - Theories using datatypes must now have theory Datatype as an
  2366     ancestor.
  2367   - The specific <typename>.induct_tac no longer exists - use the
  2368     generic induct_tac instead.
  2369   - natE has been renamed to nat.exhaust - use exhaust_tac
  2370     instead of res_inst_tac ... natE. Note that the variable
  2371     names in nat.exhaust differ from the names in natE, this
  2372     may cause some "fragile" proofs to fail.
  2373   - The theorems split_<typename>_case and split_<typename>_case_asm
  2374     have been renamed to <typename>.split and <typename>.split_asm.
  2375   - Since default sorts of type variables are now handled correctly,
  2376     some datatype definitions may have to be annotated with explicit
  2377     sort constraints.
  2378   - Primrec definitions no longer require function name and type
  2379     of recursive argument.
  2380 
  2381 Consider using isatool fixdatatype to adapt your theories and proof
  2382 scripts to the new package (backup your sources first!).
  2383 
  2384 
  2385 * HOL/record package: considerably improved implementation; now
  2386 includes concrete syntax for record types, terms, updates; theorems
  2387 for surjective pairing and splitting !!-bound record variables; proof
  2388 support is as follows:
  2389 
  2390   1) standard conversions (selectors or updates applied to record
  2391 constructor terms) are part of the standard simpset;
  2392 
  2393   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2394 made part of standard simpset and claset via addIffs;
  2395 
  2396   3) a tactic for record field splitting (record_split_tac) is part of
  2397 the standard claset (addSWrapper);
  2398 
  2399 To get a better idea about these rules you may retrieve them via
  2400 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2401 the name of your record type.
  2402 
  2403 The split tactic 3) conceptually simplifies by the following rule:
  2404 
  2405   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2406 
  2407 Thus any record variable that is bound by meta-all will automatically
  2408 blow up into some record constructor term, consequently the
  2409 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2410 solve record problems automatically.
  2411 
  2412 
  2413 * reorganized the main HOL image: HOL/Integ and String loaded by
  2414 default; theory Main includes everything;
  2415 
  2416 * automatic simplification of integer sums and comparisons, using cancellation;
  2417 
  2418 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2419 
  2420 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2421 
  2422 * many new identities for unions, intersections, set difference, etc.;
  2423 
  2424 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2425 called split_if, split_split, split_sum_case and split_nat_case (to go
  2426 with add/delsplits);
  2427 
  2428 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2429 (?x::unit) = (); this is made part of the default simpset, which COULD
  2430 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2431 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2432 unit_abs_eta_conv is added in order to counter the effect of
  2433 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2434 %u.f();
  2435 
  2436 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2437 makes more sense);
  2438 
  2439 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2440   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2441   disjointness reasoning but breaking a few old proofs.
  2442 
  2443 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2444 to 'converse' from 'inverse' (for compatibility with ZF and some
  2445 literature);
  2446 
  2447 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2448 the well-founded relation;
  2449 
  2450 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2451     Compl A.  The "Compl" syntax remains available as input syntax for this
  2452     release ONLY.
  2453 
  2454 * HOL/Update: new theory of function updates:
  2455     f(a:=b) == %x. if x=a then b else f x
  2456 may also be iterated as in f(a:=b,c:=d,...);
  2457 
  2458 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2459 
  2460 * HOL/List:
  2461   - new function list_update written xs[i:=v] that updates the i-th
  2462     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2463   - new function `upt' written [i..j(] which generates the list
  2464     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2465     bound write [i..j], which is a shorthand for [i..j+1(].
  2466   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2467 
  2468 * HOL/Arith:
  2469   - removed 'pred' (predecessor) function;
  2470   - generalized some theorems about n-1;
  2471   - many new laws about "div" and "mod";
  2472   - new laws about greatest common divisors (see theory ex/Primes);
  2473 
  2474 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2475 instead of "inverse";
  2476 
  2477 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2478   of the multiset ordering;
  2479 
  2480 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2481   (not included by default);
  2482 
  2483 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2484 
  2485 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2486   programs, i.e. different program variables may have different types.
  2487 
  2488 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2489   [previously, this check worked only if the rewrite rule was unconditional]
  2490   Now rew can involve either definitions or equalities (either == or =).
  2491 
  2492 
  2493 *** ZF ***
  2494 
  2495 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2496   only the theorems proved on ZF.ML;
  2497 
  2498 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2499   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2500   disjointness reasoning but breaking a few old proofs.
  2501 
  2502 * ZF/Update: new theory of function updates
  2503     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2504   may also be iterated as in f(a:=b,c:=d,...);
  2505 
  2506 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2507 
  2508 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2509   [previously, this check worked only if the rewrite rule was unconditional]
  2510   Now rew can involve either definitions or equalities (either == or =).
  2511 
  2512 * case_tac provided for compatibility with HOL
  2513     (like the old excluded_middle_tac, but with subgoals swapped)
  2514 
  2515 
  2516 *** Internal programming interfaces ***
  2517 
  2518 * Pure: several new basic modules made available for general use, see
  2519 also src/Pure/README;
  2520 
  2521 * improved the theory data mechanism to support encapsulation (data
  2522 kind name replaced by private Object.kind, acting as authorization
  2523 key); new type-safe user interface via functor TheoryDataFun; generic
  2524 print_data function becomes basically useless;
  2525 
  2526 * removed global_names compatibility flag -- all theory declarations
  2527 are qualified by default;
  2528 
  2529 * module Pure/Syntax now offers quote / antiquote translation
  2530 functions (useful for Hoare logic etc. with implicit dependencies);
  2531 see HOL/ex/Antiquote for an example use;
  2532 
  2533 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2534 cterm -> thm;
  2535 
  2536 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2537 subgoal;
  2538 
  2539 * Display.print_goals function moved to Locale.print_goals;
  2540 
  2541 * standard print function for goals supports current_goals_markers
  2542 variable for marking begin of proof, end of proof, start of goal; the
  2543 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2544 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2545 for example;
  2546 
  2547 
  2548 
  2549 New in Isabelle98 (January 1998)
  2550 --------------------------------
  2551 
  2552 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2553 
  2554 * changed lexical syntax of terms / types: dots made part of long
  2555 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2556 
  2557 * simpset (and claset) reference variable replaced by functions
  2558 simpset / simpset_ref;
  2559 
  2560 * no longer supports theory aliases (via merge) and non-trivial
  2561 implicit merge of thms' signatures;
  2562 
  2563 * most internal names of constants changed due to qualified names;
  2564 
  2565 * changed Pure/Sequence interface (see Pure/seq.ML);
  2566 
  2567 
  2568 *** General Changes ***
  2569 
  2570 * hierachically structured name spaces (for consts, types, axms, thms
  2571 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2572 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2573 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2574 long_names for fully qualified output names; NOTE: ML programs
  2575 (special tactics, packages etc.) referring to internal names may have
  2576 to be adapted to cope with fully qualified names; in case of severe
  2577 backward campatibility problems try setting 'global_names' at compile
  2578 time to have enrything declared within a flat name space; one may also
  2579 fine tune name declarations in theories via the 'global' and 'local'
  2580 section;
  2581 
  2582 * reimplemented the implicit simpset and claset using the new anytype
  2583 data filed in signatures; references simpset:simpset ref etc. are
  2584 replaced by functions simpset:unit->simpset and
  2585 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2586 to patch your ML files accordingly;
  2587 
  2588 * HTML output now includes theory graph data for display with Java
  2589 applet or isatool browser; data generated automatically via isatool
  2590 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2591 
  2592 * defs may now be conditional; improved rewrite_goals_tac to handle
  2593 conditional equations;
  2594 
  2595 * defs now admits additional type arguments, using TYPE('a) syntax;
  2596 
  2597 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2598 creates a new theory node; implicit merge of thms' signatures is
  2599 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2600 transfer:theory->thm->thm in (rare) cases;
  2601 
  2602 * improved handling of draft signatures / theories; draft thms (and
  2603 ctyps, cterms) are automatically promoted to real ones;
  2604 
  2605 * slightly changed interfaces for oracles: admit many per theory, named
  2606 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2607 
  2608 * print_goals: optional output of const types (set show_consts and
  2609 show_types);
  2610 
  2611 * improved output of warnings (###) and errors (***);
  2612 
  2613 * subgoal_tac displays a warning if the new subgoal has type variables;
  2614 
  2615 * removed old README and Makefiles;
  2616 
  2617 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2618 
  2619 * removed obsolete init_pps and init_database;
  2620 
  2621 * deleted the obsolete tactical STATE, which was declared by
  2622     fun STATE tacfun st = tacfun st st;
  2623 
  2624 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2625 (which abbreviates $HOME);
  2626 
  2627 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2628 use isatool fixseq to adapt your ML programs (this works for fully
  2629 qualified references to the Sequence structure only!);
  2630 
  2631 * use_thy no longer requires writable current directory; it always
  2632 reloads .ML *and* .thy file, if either one is out of date;
  2633 
  2634 
  2635 *** Classical Reasoner ***
  2636 
  2637 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2638 tactics that use classical reasoning to simplify a subgoal without
  2639 splitting it into several subgoals;
  2640 
  2641 * Safe_tac: like safe_tac but uses the default claset;
  2642 
  2643 
  2644 *** Simplifier ***
  2645 
  2646 * added simplification meta rules:
  2647     (asm_)(full_)simplify: simpset -> thm -> thm;
  2648 
  2649 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2650 logics (again);
  2651 
  2652 * added prems argument to simplification procedures;
  2653 
  2654 * HOL, FOL, ZF: added infix function `addsplits':
  2655   instead of `<simpset> setloop (split_tac <thms>)'
  2656   you can simply write `<simpset> addsplits <thms>'
  2657 
  2658 
  2659 *** Syntax ***
  2660 
  2661 * TYPE('a) syntax for type reflection terms;
  2662 
  2663 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2664 
  2665 * pretty printer: changed order of mixfix annotation preference (again!);
  2666 
  2667 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2668 
  2669 
  2670 *** HOL ***
  2671 
  2672 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2673   with `addloop' of the simplifier to faciliate case splitting in premises.
  2674 
  2675 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2676 
  2677 * HOL/Auth: new protocol proofs including some for the Internet
  2678   protocol TLS;
  2679 
  2680 * HOL/Map: new theory of `maps' a la VDM;
  2681 
  2682 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2683 cancelling out common nat summands from =, <, <= (in)equalities, or
  2684 differences; simplification procedures nat_cancel_factor for
  2685 cancelling common factor from =, <, <= (in)equalities over natural
  2686 sums; nat_cancel contains both kinds of procedures, it is installed by
  2687 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2688 
  2689 * HOL/simplifier: terms of the form
  2690   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2691   are rewritten to
  2692   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2693   and those of the form
  2694   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2695   are rewritten to
  2696   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2697 
  2698 * HOL/datatype
  2699   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2700 
  2701   P(t_case f1 ... fn x) =
  2702      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2703         ...
  2704        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2705      )
  2706 
  2707   and a theorem `split_t_case_asm' of the form
  2708 
  2709   P(t_case f1 ... fn x) =
  2710     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2711         ...
  2712        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2713      )
  2714   which can be added to a simpset via `addsplits'. The existing theorems
  2715   expand_list_case and expand_option_case have been renamed to
  2716   split_list_case and split_option_case.
  2717 
  2718 * HOL/Arithmetic:
  2719   - `pred n' is automatically converted to `n-1'.
  2720     Users are strongly encouraged not to use `pred' any longer,
  2721     because it will disappear altogether at some point.
  2722   - Users are strongly encouraged to write "0 < n" rather than
  2723     "n ~= 0". Theorems and proof tools have been modified towards this
  2724     `standard'.
  2725 
  2726 * HOL/Lists:
  2727   the function "set_of_list" has been renamed "set" (and its theorems too);
  2728   the function "nth" now takes its arguments in the reverse order and
  2729   has acquired the infix notation "!" as in "xs!n".
  2730 
  2731 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2732 
  2733 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2734   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2735 
  2736 * HOL/record: extensible records with schematic structural subtyping
  2737 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2738 still lacks various theorems and concrete record syntax;
  2739 
  2740 
  2741 *** HOLCF ***
  2742 
  2743 * removed "axioms" and "generated by" sections;
  2744 
  2745 * replaced "ops" section by extended "consts" section, which is capable of
  2746   handling the continuous function space "->" directly;
  2747 
  2748 * domain package:
  2749   . proves theorems immediately and stores them in the theory,
  2750   . creates hierachical name space,
  2751   . now uses normal mixfix annotations (instead of cinfix...),
  2752   . minor changes to some names and values (for consistency),
  2753   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2754   . separator between mutual domain defs: changed "," to "and",
  2755   . improved handling of sort constraints;  now they have to
  2756     appear on the left-hand side of the equations only;
  2757 
  2758 * fixed LAM <x,y,zs>.b syntax;
  2759 
  2760 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2761 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2762 
  2763 
  2764 *** FOL and ZF ***
  2765 
  2766 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2767   with `addloop' of the simplifier to faciliate case splitting in premises.
  2768 
  2769 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2770 in HOL, they strip ALL and --> from proved theorems;
  2771 
  2772 
  2773 
  2774 New in Isabelle94-8 (May 1997)
  2775 ------------------------------
  2776 
  2777 *** General Changes ***
  2778 
  2779 * new utilities to build / run / maintain Isabelle etc. (in parts
  2780 still somewhat experimental); old Makefiles etc. still functional;
  2781 
  2782 * new 'Isabelle System Manual';
  2783 
  2784 * INSTALL text, together with ./configure and ./build scripts;
  2785 
  2786 * reimplemented type inference for greater efficiency, better error
  2787 messages and clean internal interface;
  2788 
  2789 * prlim command for dealing with lots of subgoals (an easier way of
  2790 setting goals_limit);
  2791 
  2792 
  2793 *** Syntax ***
  2794 
  2795 * supports alternative (named) syntax tables (parser and pretty
  2796 printer); internal interface is provided by add_modesyntax(_i);
  2797 
  2798 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2799 be used in conjunction with the Isabelle symbol font; uses the
  2800 "symbols" syntax table;
  2801 
  2802 * added token_translation interface (may translate name tokens in
  2803 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2804 the current print_mode); IMPORTANT: user print translation functions
  2805 are responsible for marking newly introduced bounds
  2806 (Syntax.mark_boundT);
  2807 
  2808 * token translations for modes "xterm" and "xterm_color" that display
  2809 names in bold, underline etc. or colors (which requires a color
  2810 version of xterm);
  2811 
  2812 * infixes may now be declared with names independent of their syntax;
  2813 
  2814 * added typed_print_translation (like print_translation, but may
  2815 access type of constant);
  2816 
  2817 
  2818 *** Classical Reasoner ***
  2819 
  2820 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2821 some limitations.  Blast_tac...
  2822   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2823   + ignores elimination rules that don't have the correct format
  2824         (the conclusion MUST be a formula variable)
  2825   + ignores types, which can make HOL proofs fail
  2826   + rules must not require higher-order unification, e.g. apply_type in ZF
  2827     [message "Function Var's argument not a bound variable" relates to this]
  2828   + its proof strategy is more general but can actually be slower
  2829 
  2830 * substitution with equality assumptions no longer permutes other
  2831 assumptions;
  2832 
  2833 * minor changes in semantics of addafter (now called addaltern); renamed
  2834 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2835 (and access functions for it);
  2836 
  2837 * improved combination of classical reasoner and simplifier:
  2838   + functions for handling clasimpsets
  2839   + improvement of addss: now the simplifier is called _after_ the
  2840     safe steps.
  2841   + safe variant of addss called addSss: uses safe simplifications
  2842     _during_ the safe steps. It is more complete as it allows multiple
  2843     instantiations of unknowns (e.g. with slow_tac).
  2844 
  2845 *** Simplifier ***
  2846 
  2847 * added interface for simplification procedures (functions that
  2848 produce *proven* rewrite rules on the fly, depending on current
  2849 redex);
  2850 
  2851 * ordering on terms as parameter (used for ordered rewriting);
  2852 
  2853 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2854 
  2855 * the solver is now split into a safe and an unsafe part.
  2856 This should be invisible for the normal user, except that the
  2857 functions setsolver and addsolver have been renamed to setSolver and
  2858 addSolver; added safe_asm_full_simp_tac;
  2859 
  2860 
  2861 *** HOL ***
  2862 
  2863 * a generic induction tactic `induct_tac' which works for all datatypes and
  2864 also for type `nat';
  2865 
  2866 * a generic case distinction tactic `exhaust_tac' which works for all
  2867 datatypes and also for type `nat';
  2868 
  2869 * each datatype comes with a function `size';
  2870 
  2871 * patterns in case expressions allow tuple patterns as arguments to
  2872 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2873 
  2874 * primrec now also works with type nat;
  2875 
  2876 * recdef: a new declaration form, allows general recursive functions to be
  2877 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2878 
  2879 * the constant for negation has been renamed from "not" to "Not" to
  2880 harmonize with FOL, ZF, LK, etc.;
  2881 
  2882 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2883 infinite lists;
  2884 
  2885 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2886 
  2887 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2888 problems in commutative rings, using axiomatic type classes for + and *;
  2889 
  2890 * more examples in HOL/MiniML and HOL/Auth;
  2891 
  2892 * more default rewrite rules for quantifiers, union/intersection;
  2893 
  2894 * a new constant `arbitrary == @x.False';
  2895 
  2896 * HOLCF/IOA replaces old HOL/IOA;
  2897 
  2898 * HOLCF changes: derived all rules and arities
  2899   + axiomatic type classes instead of classes
  2900   + typedef instead of faking type definitions
  2901   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2902   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2903   + eliminated the types void, one, tr
  2904   + use unit lift and bool lift (with translations) instead of one and tr
  2905   + eliminated blift from Lift3.thy (use Def instead of blift)
  2906   all eliminated rules are derived as theorems --> no visible changes ;
  2907 
  2908 
  2909 *** ZF ***
  2910 
  2911 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2912 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2913 as ZF_cs addSIs [equalityI];
  2914 
  2915 
  2916 
  2917 New in Isabelle94-7 (November 96)
  2918 ---------------------------------
  2919 
  2920 * allowing negative levels (as offsets) in prlev and choplev;
  2921 
  2922 * super-linear speedup for large simplifications;
  2923 
  2924 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2925 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2926 FAIL); can suppress it using the command Delsimps (ex_simps @
  2927 all_simps); De Morgan laws are also now included, by default;
  2928 
  2929 * improved printing of ==>  :  ~:
  2930 
  2931 * new object-logic "Sequents" adds linear logic, while replacing LK
  2932 and Modal (thanks to Sara Kalvala);
  2933 
  2934 * HOL/Auth: correctness proofs for authentication protocols;
  2935 
  2936 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2937 examples on HOL/Auth);
  2938 
  2939 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2940 the rewriter and classical reasoner simultaneously;
  2941 
  2942 * function uresult no longer returns theorems in "standard" format;
  2943 regain previous version by: val uresult = standard o uresult;
  2944 
  2945 
  2946 
  2947 New in Isabelle94-6
  2948 -------------------
  2949 
  2950 * oracles -- these establish an interface between Isabelle and trusted
  2951 external reasoners, which may deliver results as theorems;
  2952 
  2953 * proof objects (in particular record all uses of oracles);
  2954 
  2955 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2956 
  2957 * "constdefs" section in theory files;
  2958 
  2959 * "primrec" section (HOL) no longer requires names;
  2960 
  2961 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2962 
  2963 
  2964 
  2965 New in Isabelle94-5
  2966 -------------------
  2967 
  2968 * reduced space requirements;
  2969 
  2970 * automatic HTML generation from theories;
  2971 
  2972 * theory files no longer require "..." (quotes) around most types;
  2973 
  2974 * new examples, including two proofs of the Church-Rosser theorem;
  2975 
  2976 * non-curried (1994) version of HOL is no longer distributed;
  2977 
  2978 
  2979 
  2980 New in Isabelle94-4
  2981 -------------------
  2982 
  2983 * greatly reduced space requirements;
  2984 
  2985 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2986 
  2987 * searchable theorem database (see the section "Retrieving theorems" on
  2988 page 8 of the Reference Manual);
  2989 
  2990 * new examples, including Grabczewski's monumental case study of the
  2991 Axiom of Choice;
  2992 
  2993 * The previous version of HOL renamed to Old_HOL;
  2994 
  2995 * The new version of HOL (previously called CHOL) uses a curried syntax
  2996 for functions.  Application looks like f a b instead of f(a,b);
  2997 
  2998 * Mutually recursive inductive definitions finally work in HOL;
  2999 
  3000 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3001 translates to the operator "split";
  3002 
  3003 
  3004 
  3005 New in Isabelle94-3
  3006 -------------------
  3007 
  3008 * new infix operator, addss, allowing the classical reasoner to
  3009 perform simplification at each step of its search.  Example:
  3010         fast_tac (cs addss ss)
  3011 
  3012 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3013 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3014 look like (a,b) instead of <a,b>;
  3015 
  3016 * PLEASE NOTE: CHOL will eventually replace HOL!
  3017 
  3018 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3019 It translates to the operator "split".  A new theory of integers is available;
  3020 
  3021 * In ZF, integer numerals now denote two's-complement binary integers.
  3022 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3023 
  3024 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3025 of the Axiom of Choice;
  3026 
  3027 
  3028 
  3029 New in Isabelle94-2
  3030 -------------------
  3031 
  3032 * Significantly faster resolution;
  3033 
  3034 * the different sections in a .thy file can now be mixed and repeated
  3035 freely;
  3036 
  3037 * Database of theorems for FOL, HOL and ZF.  New
  3038 commands including qed, qed_goal and bind_thm store theorems in the database.
  3039 
  3040 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3041 a given theory (thms_of), or find out what theory a theorem was proved in
  3042 (theory_of_thm);
  3043 
  3044 * Bugs fixed in the inductive definition and datatype packages;
  3045 
  3046 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3047 and HOL_dup_cs obsolete;
  3048 
  3049 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3050 have been removed;
  3051 
  3052 * Simpler definition of function space in ZF;
  3053 
  3054 * new results about cardinal and ordinal arithmetic in ZF;
  3055 
  3056 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3057 types;
  3058 
  3059 
  3060 $Id$