NEWS
author kleing
Mon May 30 10:23:15 2005 +0200 (2005-05-30)
changeset 16111 d06dc7975731
parent 16104 dab13c4685ba
child 16112 27585e65028b
permissions -rw-r--r--
updated para on searching
     1 Isabelle NEWS -- history user-relevant changes
     2 ==============================================
     3 
     4 New in this Isabelle release
     5 ----------------------------
     6 
     7 *** General ***
     8 
     9 * Theory headers: the new header syntax for Isar theories is
    10 
    11   theory <name>
    12   imports <theory1> ... <theoryn>
    13   begin
    14 
    15   optionally also with a "files" section. The syntax
    16 
    17   theory <name> = <theory1> + ... + <theoryn>:
    18 
    19   will still be supported for some time but will eventually disappear.
    20   The syntax of old-style theories has not changed.
    21 
    22 * Theory loader: parent theories can now also be referred to via
    23   relative and absolute paths.
    24 
    25 * Provers/quasi.ML: new transitivity reasoners for transitivity only
    26   and quasi orders.
    27 
    28 * Provers/trancl.ML: new transitivity reasoner for transitive and
    29   reflexive-transitive closure of relations.
    30 
    31 * Provers/blast.ML: new reference depth_limit to make blast's depth
    32   limit (previously hard-coded with a value of 20) user-definable.
    33 
    34 * Provers: new version of the subst method, for single-step rewriting: it now
    35   works in bound variable contexts. New is subst (asm), for rewriting an
    36   assumption. Thanks to Lucas Dixon! INCOMPATIBILITY: may rewrite a different
    37   subterm than the original subst method, which is still available under the
    38   name simplesubst.
    39 
    40 * Pure: thin_tac now works even if the assumption being deleted contains !! or ==>. 
    41   More generally, erule now works even if the major premise of the elimination rule
    42   contains !! or ==>.
    43 
    44 * Pure: considerably improved version of 'constdefs' command.  Now
    45   performs automatic type-inference of declared constants; additional
    46   support for local structure declarations (cf. locales and HOL
    47   records), see also isar-ref manual.  Potential INCOMPATIBILITY: need
    48   to observe strictly sequential dependencies of definitions within a
    49   single 'constdefs' section; moreover, the declared name needs to be
    50   an identifier.  If all fails, consider to fall back on 'consts' and
    51   'defs' separately.
    52 
    53 * Pure: improved indexed syntax and implicit structures.  First of
    54   all, indexed syntax provides a notational device for subscripted
    55   application, using the new syntax \<^bsub>term\<^esub> for arbitrary
    56   expressions.  Secondly, in a local context with structure
    57   declarations, number indexes \<^sub>n or the empty index (default
    58   number 1) refer to a certain fixed variable implicitly; option
    59   show_structs controls printing of implicit structures.  Typical
    60   applications of these concepts involve record types and locales.
    61 
    62 * Pure: clear separation of logical types and nonterminals, where the
    63   latter may only occur in 'syntax' specifications or type
    64   abbreviations.  Before that distinction was only partially
    65   implemented via type class "logic" vs. "{}".  Potential
    66   INCOMPATIBILITY in rare cases of improper use of 'types'/'consts'
    67   instead of 'nonterminals'/'syntax'.  Some very exotic syntax
    68   specifications may require further adaption (e.g. Cube/Base.thy).
    69 
    70 * Pure: removed obsolete type class "logic", use the top sort {}
    71   instead.  Note that non-logical types should be declared as
    72   'nonterminals' rather than 'types'.  INCOMPATIBILITY for new
    73   object-logic specifications.
    74 
    75 * Pure: command 'no_syntax' removes grammar declarations (and
    76   translations) resulting from the given syntax specification, which
    77   is interpreted in the same manner as for the 'syntax' command.
    78 
    79 * Pure: print_tac now outputs the goal through the trace channel.
    80 
    81 * Pure: reference NameSpace.unique_names included.  If true the
    82   (shortest) namespace-prefix is printed to disambiguate conflicts (as
    83   yet). If false the first entry wins (as during parsing). Default
    84   value is true.
    85 
    86 * Pure: tuned internal renaming of symbolic identifiers -- attach
    87   primes instead of base 26 numbers.
    88 
    89 * Pure: new flag show_question_marks controls printing of leading
    90   question marks in schematic variable names.
    91 
    92 * Pure: new version of thms_containing that searches for a list of
    93   criteria instead of a list of constants. Known criteria are: intro,
    94   elim, dest, name:string, simp:term, and any term. Criteria can be 
    95   preceded by '-' to select theorems that do not match. Intro, elim, 
    96   dest select theorems that match the current goal, name:s selects
    97   theorems whose fully qualified name contain s, and simp:term selects
    98   all simplification rules whose lhs match term.  Any other term is 
    99   interpreted as pattern and selects all theorem matching the
   100   pattern. Available in ProofGeneral under 'ProofGeneral -> Find
   101   Theorems' or C-c C-f.
   102 
   103   Example: C-c C-f (100) "(_::nat) + _ + _" intro -name:"HOL."
   104 
   105   prints the last 100 theorems matching the pattern "(_::nat) + _ + _",
   106   matching the current goal as introduction rule and not having "HOL." 
   107   in their name (i.e. not being defined in theory HOL).
   108 
   109 * Pure/Syntax: In schematic variable names, *any* symbol following
   110   \<^isub> or \<^isup> is now treated as part of the base name.  For
   111   example, the following works without printing of ugly ".0" indexes:
   112 
   113     lemma "x\<^isub>1 = x\<^isub>2 ==> x\<^isub>2 = x\<^isub>1"
   114       by simp
   115 
   116 * Pure/Syntax: inner syntax includes (*(*nested*) comments*).
   117 
   118 * Pure/Syntax: pretty pinter now supports unbreakable blocks,
   119   specified in mixfix annotations as "(00...)".
   120 
   121 * Pure/Syntax: 'advanced' translation functions (parse_translation
   122   etc.) may depend on the signature of the theory context being
   123   presently used for parsing/printing, see also isar-ref manual.
   124 
   125 * Pure/Simplifier: you can control the depth to which conditional rewriting
   126   is traced via the PG menu Isabelle -> Settings -> Trace Simp Depth Limit.
   127 
   128 * Pure/Simplifier: simplification procedures may now take the current
   129   simpset into account (cf. Simplifier.simproc(_i) / mk_simproc
   130   interface), which is very useful for calling the Simplifier
   131   recursively.  Minor INCOMPATIBILITY: the 'prems' argument of
   132   simprocs is gone -- use prems_of_ss on the simpset instead.
   133   Moreover, the low-level mk_simproc no longer applies Logic.varify
   134   internally, to allow for use in a context of fixed variables.
   135 
   136 * Isar debugging: new reference Toplevel.debug; default false.  Set to
   137   make printing of exceptions THM, TERM, TYPE and THEORY more verbose.
   138   
   139 * Locales: modifications regarding "includes"
   140   - "includes" disallowed in declaration of named locales (command "locale").
   141   - Fixed parameter management in theorem generation for goals with "includes".
   142     INCOMPATIBILITY: rarely, the generated theorem statement is different.
   143 
   144 * Locales: locale expressions permit optional mixfix redeclaration for
   145   renamed parameters.
   146 
   147 * Locales: new commands for the interpretation of locale expressions
   148   in theories (interpretation) and proof contexts (interpret).  These take an
   149   instantiation of the locale parameters and compute proof obligations from
   150   the instantiated specification.  After the obligations have been discharged,
   151   the instantiated theorems of the locale are added to the theory or proof
   152   context.  Interpretation is smart in that already active interpretations
   153   do not occur in proof obligations, neither are instantiated theorems stored
   154   in duplicate.
   155   Use print_interps to inspect active interpretations of a particular locale.
   156   For details, see the Isar Reference manual.
   157 
   158 * Locales: proper static binding of attribute syntax -- i.e. types /
   159   terms / facts mentioned as arguments are always those of the locale
   160   definition context, independently of the context of later
   161   invocations.  Moreover, locale operations (renaming and type / term
   162   instantiation) are applied to attribute arguments as expected.
   163 
   164   INCOMPATIBILITY of the ML interface: always pass Attrib.src instead
   165   of actual attributes; rare situations may require Attrib.attribute
   166   to embed those attributes into Attrib.src that lack concrete syntax.
   167 
   168   Attribute implementations need to cooperate properly with the static
   169   binding mechanism.  Basic parsers Args.XXX_typ/term/prop and
   170   Attrib.XXX_thm etc. already do the right thing without further
   171   intervention.  Only unusual applications -- such as "where" or "of"
   172   (cf. src/Pure/Isar/attrib.ML), which process arguments depending
   173   both on the context and the facts involved -- may have to assign
   174   parsed values to argument tokens explicitly.
   175 
   176 * Attributes 'induct' and 'cases': type or set names may now be
   177   locally fixed variables as well.
   178 
   179 * Isar: new syntax 'name(i-j, i-, i, ...)' for referring to specific
   180   selections of theorems in named facts via indices.
   181 
   182 * Pure: reorganized bootstrapping of the Pure theories; CPure is now
   183   derived from Pure, which contains all common declarations already.
   184   Both theories are defined via plain Isabelle/Isar .thy files.
   185   INCOMPATIBILITY: elements of CPure (such as the CPure.intro /
   186   CPure.elim / CPure.dest attributes) now appear in the Pure name
   187   space; use isatool fixcpure to adapt your theory and ML sources.
   188 
   189 * Provers/simplifier.ML has been moved to Pure, where Simplifier.setup
   190   is peformed already.  Object-logics merely need to finish their
   191   initial simpset configuration as before.
   192 
   193 
   194 *** Document preparation ***
   195 
   196 * Several new antiquotation:
   197 
   198   @{term_type term} prints a term with its type annotated;
   199 
   200   @{typeof term} prints the type of a term;
   201 
   202   @{const const} is the same as @{term const}, but checks
   203     that the argument is a known logical constant;
   204 
   205   @{term_style style term} and @{thm_style style thm} print a term or
   206     theorem applying a "style" to it
   207 
   208   Predefined styles are "lhs" and "rhs" printing the lhs/rhs of
   209   definitions, equations, inequations etc. and "conclusion" printing
   210   only the conclusion of a meta-logical statement theorem.  Styles may
   211   be defined via TermStyle.add_style in ML.  See the "LaTeX Sugar"
   212   document for more information.
   213 
   214 * Antiquotations now provide the option 'locale=NAME' to specify an
   215   alternative context used for evaluating and printing the subsequent
   216   argument, as in @{thm [locale=LC] fold_commute}, for example.
   217 
   218 * Commands 'display_drafts' and 'print_drafts' perform simple output
   219   of raw sources.  Only those symbols that do not require additional
   220   LaTeX packages (depending on comments in isabellesym.sty) are
   221   displayed properly, everything else is left verbatim.  We use
   222   isatool display and isatool print as front ends; these are subject
   223   to the DVI/PDF_VIEWER and PRINT_COMMAND settings, respectively.
   224 
   225 * Proof scripts as well as some other commands such as ML or
   226   parse/print_translation can now be hidden in the document.  Hiding
   227   is enabled by default, and can be disabled either via the option '-H
   228   false' of isatool usedir or by resetting the reference variable
   229   IsarOutput.hide_commands. Additional commands to be hidden may be
   230   declared using IsarOutput.add_hidden_commands.
   231 
   232 
   233 *** HOL ***
   234 
   235 * Datatype induction via method `induct' now preserves the name of the
   236   induction variable. For example, when proving P(xs::'a list) by induction
   237   on xs, the induction step is now P(xs) ==> P(a#xs) rather than
   238   P(list) ==> P(a#list) as previously.
   239 
   240 * HOL/record: reimplementation of records. Improved scalability for
   241   records with many fields, avoiding performance problems for type
   242   inference. Records are no longer composed of nested field types, but
   243   of nested extension types. Therefore the record type only grows
   244   linear in the number of extensions and not in the number of fields.
   245   The top-level (users) view on records is preserved.  Potential
   246   INCOMPATIBILITY only in strange cases, where the theory depends on
   247   the old record representation. The type generated for a record is
   248   called <record_name>_ext_type.
   249 
   250 * HOL/record: Reference record_quick_and_dirty_sensitive can be
   251   enabled to skip the proofs triggered by a record definition or a
   252   simproc (if quick_and_dirty is enabled). Definitions of large
   253   records can take quite long.
   254 
   255 * HOL/record: "record_upd_simproc" for simplification of multiple
   256   record updates enabled by default.  Moreover, trivial updates are
   257   also removed: r(|x := x r|) = r.  INCOMPATIBILITY: old proofs break
   258   occasionally, since simplification is more powerful by default.
   259 
   260 * HOL: symbolic syntax of Hilbert Choice Operator is now as follows:
   261 
   262   syntax (epsilon)
   263     "_Eps" :: "[pttrn, bool] => 'a"    ("(3\<some>_./ _)" [0, 10] 10)
   264 
   265   The symbol \<some> is displayed as the alternative epsilon of LaTeX
   266   and x-symbol; use option '-m epsilon' to get it actually printed.
   267   Moreover, the mathematically important symbolic identifier
   268   \<epsilon> becomes available as variable, constant etc.
   269 
   270 * HOL: "x > y" abbreviates "y < x" and "x >= y" abbreviates "y <= x".
   271   Similarly for all quantifiers: "ALL x > y" etc.  The x-symbol for >=
   272   is \<ge>.
   273 
   274 * HOL/Set: "{x:A. P}" abbreviates "{x. x:A & P}" (and similarly for
   275   "\<in>" instead of ":").
   276 
   277 * HOL/SetInterval: The syntax for open intervals has changed:
   278 
   279   Old         New
   280   {..n(}   -> {..<n}
   281   {)n..}   -> {n<..}
   282   {m..n(}  -> {m..<n}
   283   {)m..n}  -> {m<..n}
   284   {)m..n(} -> {m<..<n}
   285 
   286   The old syntax is still supported but will disappear in the future.
   287   For conversion use the following emacs search and replace patterns:
   288 
   289   {)\([^\.]*\)\.\.  ->  {\1<\.\.}
   290   \.\.\([^(}]*\)(}  ->  \.\.<\1}
   291 
   292   They are not perfect but work quite well.
   293 
   294 * HOL: The syntax for 'setsum', summation over finite sets, has changed:
   295 
   296   The syntax for 'setsum (%x. e) A' used to be '\<Sum>x:A. e'
   297   and is now either 'SUM x:A. e' or '\<Sum>x\<in>A. e'.
   298 
   299   There is new syntax for summation over finite sets:
   300 
   301   '\<Sum>x | P. e'    is the same as  'setsum (%x. e) {x. P}'
   302   '\<Sum>x=a..b. e'   is the same as  'setsum (%x. e) {a..b}'
   303   '\<Sum>x=a..<b. e'  is the same as  'setsum (%x. e) {a..<b}'
   304   '\<Sum>x<k. e'      is the same as  'setsum (%x. e) {..<k}'
   305 
   306   Function 'Summation' over nat is gone, its syntax '\<Sum>i<k. e'
   307   now translates into 'setsum' as above.
   308 
   309 * HOL: Finite set induction: In Isar proofs, the insert case is now
   310   "case (insert x F)" instead of the old counterintuitive "case (insert F x)".
   311 
   312 * HOL/Simplifier:
   313 
   314   - Is now set up to reason about transitivity chains involving "trancl"
   315   (r^+) and "rtrancl" (r^*) by setting up tactics provided by
   316   Provers/trancl.ML as additional solvers.  INCOMPATIBILITY: old proofs break
   317   occasionally as simplification may now solve more goals than previously.
   318 
   319   - Converts x <= y into x = y if assumption y <= x is present.  Works for
   320   all partial orders (class "order"), in particular numbers and sets. For
   321   linear orders (e.g. numbers) it treats ~ x < y just like y <= x.
   322 
   323   - Simproc for "let x = a in f x"
   324   If a is a free or bound variable or a constant then the let is unfolded.
   325   Otherwise first a is simplified to a', and then f a' is simplified to
   326   g. If possible we abstract a' from g arriving at "let x = a' in g' x",
   327   otherwise we unfold the let and arrive at g. The simproc can be 
   328   enabled/disabled by the reference use_let_simproc. Potential
   329   INCOMPATIBILITY since simplification is more powerful by default.
   330 
   331 * HOL: The 'refute' command has been extended to support a much larger
   332   fragment of HOL, including axiomatic type classes, constdefs and typedefs,
   333   inductive datatypes and recursion.
   334 
   335 
   336 *** HOLCF ***
   337 
   338 * HOLCF: discontinued special version of 'constdefs' (which used to
   339   support continuous functions) in favor of the general Pure one with
   340   full type-inference.
   341 
   342 
   343 *** ZF ***
   344 
   345 * ZF/ex/{Group,Ring}: examples in abstract algebra, including the
   346   First Isomorphism Theorem (on quotienting by the kernel of a
   347   homomorphism).
   348 
   349 * ZF/Simplifier: install second copy of type solver that actually
   350   makes use of TC rules declared to Isar proof contexts (or locales);
   351   the old version is still required for ML proof scripts.
   352 
   353 
   354 *** System ***
   355 
   356 * Allow symlinks to all proper Isabelle executables (Isabelle,
   357   isabelle, isatool etc.).
   358 
   359 * isabelle-process: Poly/ML no longer needs Perl to run an interactive
   360   session.
   361 
   362 * ISABELLE_DOC_FORMAT setting specifies preferred document format (for
   363   isatool doc, isatool mkdir, display_drafts etc.).
   364 
   365 * isatool usedir: option -f allows specification of the ML file to be
   366   used by Isabelle; default is ROOT.ML.
   367 
   368 * HOL: isatool dimacs2hol converts files in DIMACS CNF format
   369   (containing Boolean satisfiability problems) into Isabelle/HOL
   370   theories.
   371 
   372 
   373 *** ML ***
   374 
   375 * Pure/library.ML no longer defines its own option datatype, but uses
   376   that of the SML basis, which has constructors NONE and SOME instead
   377   of None and Some, as well as exception Option.Option instead of
   378   OPTION.  The functions the, if_none, is_some, is_none have been
   379   adapted accordingly, while Option.map replaces apsome.
   380 
   381 * The exception LIST is no more, the standard exceptions Empty and
   382   Subscript, as well as Library.UnequalLengths are used instead.  This
   383   means that function like Library.hd and Library.tl are gone, as the
   384   standard hd and tl functions suffice.
   385 
   386   A number of basic functions are now no longer exported to the ML
   387   toplevel, as they are variants of standard functions.  The following
   388   suggests how one can translate existing code:
   389 
   390     rev_append xs ys = List.revAppend (xs, ys)
   391     nth_elem (i, xs) = List.nth (xs, i)
   392     last_elem xs = List.last xs
   393     flat xss = List.concat xss
   394     seq fs = app fs
   395     partition P xs = List.partition P xs
   396     filter P xs = List.filter P xs
   397     mapfilter f xs = List.mapPartial f xs
   398 
   399 * Pure: output via the Isabelle channels of writeln/warning/error
   400   etc. is now passed through Output.output, with a hook for arbitrary
   401   transformations depending on the print_mode (cf. Output.add_mode --
   402   the first active mode that provides a output function wins).
   403   Already formatted output may be embedded into further text via
   404   Output.raw; the result of Pretty.string_of/str_of and derived
   405   functions (string_of_term/cterm/thm etc.) is already marked raw to
   406   accommodate easy composition of diagnostic messages etc.
   407   Programmers rarely need to care about Output.output or Output.raw at
   408   all, with some notable exceptions: Output.output is required when
   409   bypassing the standard channels (writeln etc.), or in token
   410   translations to produce properly formatted results; Output.raw is
   411   required when capturing already output material that will eventually
   412   be presented to the user a second time.  For the default print mode,
   413   both Output.output and Output.raw have no effect.
   414 
   415 * Provers: Simplifier and Classical Reasoner now support proof context
   416   dependent plug-ins (simprocs, solvers, wrappers etc.).  These extra
   417   components are stored in the theory and patched into the
   418   simpset/claset when used in an Isar proof context.  Context
   419   dependent components are maintained by the following theory
   420   operations:
   421 
   422     Simplifier.add_context_simprocs
   423     Simplifier.del_context_simprocs
   424     Simplifier.set_context_subgoaler
   425     Simplifier.reset_context_subgoaler
   426     Simplifier.add_context_looper
   427     Simplifier.del_context_looper
   428     Simplifier.add_context_unsafe_solver
   429     Simplifier.add_context_safe_solver
   430 
   431     Classical.add_context_safe_wrapper
   432     Classical.del_context_safe_wrapper
   433     Classical.add_context_unsafe_wrapper
   434     Classical.del_context_unsafe_wrapper
   435 
   436   IMPORTANT NOTE: proof tools (methods etc.) need to use
   437   local_simpset_of and local_claset_of to instead of the primitive
   438   Simplifier.get_local_simpset and Classical.get_local_claset,
   439   respectively, in order to see the context dependent fields!
   440 
   441 
   442 
   443 New in Isabelle2004 (April 2004)
   444 --------------------------------
   445 
   446 *** General ***
   447 
   448 * Provers/order.ML:  new efficient reasoner for partial and linear orders.
   449   Replaces linorder.ML.
   450 
   451 * Pure: Greek letters (except small lambda, \<lambda>), as well as Gothic
   452   (\<aa>...\<zz>\<AA>...\<ZZ>), calligraphic (\<A>...\<Z>), and Euler
   453   (\<a>...\<z>), are now considered normal letters, and can therefore
   454   be used anywhere where an ASCII letter (a...zA...Z) has until
   455   now. COMPATIBILITY: This obviously changes the parsing of some
   456   terms, especially where a symbol has been used as a binder, say
   457   '\<Pi>x. ...', which is now a type error since \<Pi>x will be parsed
   458   as an identifier.  Fix it by inserting a space around former
   459   symbols.  Call 'isatool fixgreek' to try to fix parsing errors in
   460   existing theory and ML files.
   461 
   462 * Pure: Macintosh and Windows line-breaks are now allowed in theory files.
   463 
   464 * Pure: single letter sub/superscripts (\<^isub> and \<^isup>) are now
   465   allowed in identifiers. Similar to Greek letters \<^isub> is now considered
   466   a normal (but invisible) letter. For multiple letter subscripts repeat
   467   \<^isub> like this: x\<^isub>1\<^isub>2.
   468 
   469 * Pure: There are now sub-/superscripts that can span more than one
   470   character. Text between \<^bsub> and \<^esub> is set in subscript in
   471   ProofGeneral and LaTeX, text between \<^bsup> and \<^esup> in
   472   superscript. The new control characters are not identifier parts.
   473 
   474 * Pure: Control-symbols of the form \<^raw:...> will literally print the
   475   content of "..." to the latex file instead of \isacntrl... . The "..."
   476   may consist of any printable characters excluding the end bracket >.
   477 
   478 * Pure: Using new Isar command "finalconsts" (or the ML functions
   479   Theory.add_finals or Theory.add_finals_i) it is now possible to
   480   declare constants "final", which prevents their being given a definition
   481   later.  It is useful for constants whose behaviour is fixed axiomatically
   482   rather than definitionally, such as the meta-logic connectives.
   483 
   484 * Pure: 'instance' now handles general arities with general sorts
   485   (i.e. intersections of classes),
   486 
   487 * Presentation: generated HTML now uses a CSS style sheet to make layout
   488   (somewhat) independent of content. It is copied from lib/html/isabelle.css.
   489   It can be changed to alter the colors/layout of generated pages.
   490 
   491 
   492 *** Isar ***
   493 
   494 * Tactic emulation methods rule_tac, erule_tac, drule_tac, frule_tac,
   495   cut_tac, subgoal_tac and thin_tac:
   496   - Now understand static (Isar) contexts.  As a consequence, users of Isar
   497     locales are no longer forced to write Isar proof scripts.
   498     For details see Isar Reference Manual, paragraph 4.3.2: Further tactic
   499     emulations.
   500   - INCOMPATIBILITY: names of variables to be instantiated may no
   501     longer be enclosed in quotes.  Instead, precede variable name with `?'.
   502     This is consistent with the instantiation attribute "where".
   503 
   504 * Attributes "where" and "of":
   505   - Now take type variables of instantiated theorem into account when reading
   506     the instantiation string.  This fixes a bug that caused instantiated
   507     theorems to have too special types in some circumstances.
   508   - "where" permits explicit instantiations of type variables.
   509 
   510 * Calculation commands "moreover" and "also" no longer interfere with
   511   current facts ("this"), admitting arbitrary combinations with "then"
   512   and derived forms.
   513 
   514 * Locales:
   515   - Goal statements involving the context element "includes" no longer
   516     generate theorems with internal delta predicates (those ending on
   517     "_axioms") in the premise.
   518     Resolve particular premise with <locale>.intro to obtain old form.
   519   - Fixed bug in type inference ("unify_frozen") that prevented mix of target
   520     specification and "includes" elements in goal statement.
   521   - Rule sets <locale>.intro and <locale>.axioms no longer declared as
   522     [intro?] and [elim?] (respectively) by default.
   523   - Experimental command for instantiation of locales in proof contexts:
   524         instantiate <label>[<attrs>]: <loc>
   525     Instantiates locale <loc> and adds all its theorems to the current context
   526     taking into account their attributes.  Label and attrs are optional
   527     modifiers, like in theorem declarations.  If present, names of
   528     instantiated theorems are qualified with <label>, and the attributes
   529     <attrs> are applied after any attributes these theorems might have already.
   530       If the locale has assumptions, a chained fact of the form
   531     "<loc> t1 ... tn" is expected from which instantiations of the parameters
   532     are derived.  The command does not support old-style locales declared
   533     with "locale (open)".
   534       A few (very simple) examples can be found in FOL/ex/LocaleInst.thy.
   535 
   536 * HOL: Tactic emulation methods induct_tac and case_tac understand static
   537   (Isar) contexts.
   538 
   539 
   540 *** HOL ***
   541 
   542 * Proof import: new image HOL4 contains the imported library from
   543   the HOL4 system with about 2500 theorems. It is imported by
   544   replaying proof terms produced by HOL4 in Isabelle. The HOL4 image
   545   can be used like any other Isabelle image.  See
   546   HOL/Import/HOL/README for more information.
   547 
   548 * Simplifier:
   549   - Much improved handling of linear and partial orders.
   550     Reasoners for linear and partial orders are set up for type classes
   551     "linorder" and "order" respectively, and are added to the default simpset
   552     as solvers.  This means that the simplifier can build transitivity chains
   553     to solve goals from the assumptions.
   554   - INCOMPATIBILITY: old proofs break occasionally.  Typically, applications
   555     of blast or auto after simplification become unnecessary because the goal
   556     is solved by simplification already.
   557 
   558 * Numerics: new theory Ring_and_Field contains over 250 basic numerical laws,
   559     all proved in axiomatic type classes for semirings, rings and fields.
   560 
   561 * Numerics:
   562   - Numeric types (nat, int, and in HOL-Complex rat, real, complex, etc.) are
   563     now formalized using the Ring_and_Field theory mentioned above.
   564   - INCOMPATIBILITY: simplification and arithmetic behaves somewhat differently
   565     than before, because now they are set up once in a generic manner.
   566   - INCOMPATIBILITY: many type-specific arithmetic laws have gone.
   567     Look for the general versions in Ring_and_Field (and Power if they concern
   568     exponentiation).
   569 
   570 * Type "rat" of the rational numbers is now available in HOL-Complex.
   571 
   572 * Records:
   573   - Record types are now by default printed with their type abbreviation
   574     instead of the list of all field types. This can be configured via
   575     the reference "print_record_type_abbr".
   576   - Simproc "record_upd_simproc" for simplification of multiple updates added
   577     (not enabled by default).
   578   - Simproc "record_ex_sel_eq_simproc" to simplify EX x. sel r = x resp.
   579     EX x. x = sel r to True (not enabled by default).
   580   - Tactic "record_split_simp_tac" to split and simplify records added.
   581 
   582 * 'specification' command added, allowing for definition by
   583   specification.  There is also an 'ax_specification' command that
   584   introduces the new constants axiomatically.
   585 
   586 * arith(_tac) is now able to generate counterexamples for reals as well.
   587 
   588 * HOL-Algebra: new locale "ring" for non-commutative rings.
   589 
   590 * HOL-ex: InductiveInvariant_examples illustrates advanced recursive function
   591   definitions, thanks to Sava Krsti\'{c} and John Matthews.
   592 
   593 * HOL-Matrix: a first theory for matrices in HOL with an application of
   594   matrix theory to linear programming.
   595 
   596 * Unions and Intersections:
   597   The latex output syntax of UN and INT has been changed
   598   from "\Union x \in A. B" to "\Union_{x \in A} B"
   599   i.e. the index formulae has become a subscript.
   600   Similarly for "\Union x. B", and for \Inter instead of \Union.
   601 
   602 * Unions and Intersections over Intervals:
   603   There is new short syntax "UN i<=n. A" for "UN i:{0..n}. A". There is
   604   also an x-symbol version with subscripts "\<Union>\<^bsub>i <= n\<^esub>. A"
   605   like in normal math, and corresponding versions for < and for intersection.
   606 
   607 * HOL/List: Ordering "lexico" is renamed "lenlex" and the standard
   608   lexicographic dictonary ordering has been added as "lexord".
   609 
   610 * ML: the legacy theory structures Int and List have been removed. They had
   611   conflicted with ML Basis Library structures having the same names.
   612 
   613 * 'refute' command added to search for (finite) countermodels.  Only works
   614   for a fragment of HOL.  The installation of an external SAT solver is
   615   highly recommended.  See "HOL/Refute.thy" for details.
   616 
   617 * 'quickcheck' command: Allows to find counterexamples by evaluating
   618   formulae under an assignment of free variables to random values.
   619   In contrast to 'refute', it can deal with inductive datatypes,
   620   but cannot handle quantifiers. See "HOL/ex/Quickcheck_Examples.thy"
   621   for examples.
   622 
   623 
   624 *** HOLCF ***
   625 
   626 * Streams now come with concatenation and are part of the HOLCF image
   627 
   628 
   629 
   630 New in Isabelle2003 (May 2003)
   631 ------------------------------
   632 
   633 *** General ***
   634 
   635 * Provers/simplifier:
   636 
   637   - Completely reimplemented method simp (ML: Asm_full_simp_tac):
   638     Assumptions are now subject to complete mutual simplification,
   639     not just from left to right. The simplifier now preserves
   640     the order of assumptions.
   641 
   642     Potential INCOMPATIBILITY:
   643 
   644     -- simp sometimes diverges where the old version did
   645        not, e.g. invoking simp on the goal
   646 
   647         [| P (f x); y = x; f x = f y |] ==> Q
   648 
   649        now gives rise to the infinite reduction sequence
   650 
   651         P(f x) --(f x = f y)--> P(f y) --(y = x)--> P(f x) --(f x = f y)--> ...
   652 
   653        Using "simp (asm_lr)" (ML: Asm_lr_simp_tac) instead often solves this
   654        kind of problem.
   655 
   656     -- Tactics combining classical reasoner and simplification (such as auto)
   657        are also affected by this change, because many of them rely on
   658        simp. They may sometimes diverge as well or yield a different numbers
   659        of subgoals. Try to use e.g. force, fastsimp, or safe instead of auto
   660        in case of problems. Sometimes subsequent calls to the classical
   661        reasoner will fail because a preceeding call to the simplifier too
   662        eagerly simplified the goal, e.g. deleted redundant premises.
   663 
   664   - The simplifier trace now shows the names of the applied rewrite rules
   665 
   666   - You can limit the number of recursive invocations of the simplifier
   667     during conditional rewriting (where the simplifie tries to solve the
   668     conditions before applying the rewrite rule):
   669     ML "simp_depth_limit := n"
   670     where n is an integer. Thus you can force termination where previously
   671     the simplifier would diverge.
   672 
   673   - Accepts free variables as head terms in congruence rules.  Useful in Isar.
   674 
   675   - No longer aborts on failed congruence proof.  Instead, the
   676     congruence is ignored.
   677 
   678 * Pure: New generic framework for extracting programs from constructive
   679   proofs. See HOL/Extraction.thy for an example instantiation, as well
   680   as HOL/Extraction for some case studies.
   681 
   682 * Pure: The main goal of the proof state is no longer shown by default, only
   683 the subgoals. This behaviour is controlled by a new flag.
   684    PG menu: Isabelle/Isar -> Settings -> Show Main Goal
   685 (ML: Proof.show_main_goal).
   686 
   687 * Pure: You can find all matching introduction rules for subgoal 1, i.e. all
   688 rules whose conclusion matches subgoal 1:
   689       PG menu: Isabelle/Isar -> Show me -> matching rules
   690 The rules are ordered by how closely they match the subgoal.
   691 In particular, rules that solve a subgoal outright are displayed first
   692 (or rather last, the way they are printed).
   693 (ML: ProofGeneral.print_intros())
   694 
   695 * Pure: New flag trace_unify_fail causes unification to print
   696 diagnostic information (PG: in trace buffer) when it fails. This is
   697 useful for figuring out why single step proofs like rule, erule or
   698 assumption failed.
   699 
   700 * Pure: Locale specifications now produce predicate definitions
   701 according to the body of text (covering assumptions modulo local
   702 definitions); predicate "loc_axioms" covers newly introduced text,
   703 while "loc" is cumulative wrt. all included locale expressions; the
   704 latter view is presented only on export into the global theory
   705 context; potential INCOMPATIBILITY, use "(open)" option to fall back
   706 on the old view without predicates;
   707 
   708 * Pure: predefined locales "var" and "struct" are useful for sharing
   709 parameters (as in CASL, for example); just specify something like
   710 ``var x + var y + struct M'' as import;
   711 
   712 * Pure: improved thms_containing: proper indexing of facts instead of
   713 raw theorems; check validity of results wrt. current name space;
   714 include local facts of proof configuration (also covers active
   715 locales), cover fixed variables in index; may use "_" in term
   716 specification; an optional limit for the number of printed facts may
   717 be given (the default is 40);
   718 
   719 * Pure: disallow duplicate fact bindings within new-style theory files
   720 (batch-mode only);
   721 
   722 * Provers: improved induct method: assumptions introduced by case
   723 "foo" are split into "foo.hyps" (from the rule) and "foo.prems" (from
   724 the goal statement); "foo" still refers to all facts collectively;
   725 
   726 * Provers: the function blast.overloaded has been removed: all constants
   727 are regarded as potentially overloaded, which improves robustness in exchange
   728 for slight decrease in efficiency;
   729 
   730 * Provers/linorder: New generic prover for transitivity reasoning over
   731 linear orders.  Note: this prover is not efficient!
   732 
   733 * Isar: preview of problems to finish 'show' now produce an error
   734 rather than just a warning (in interactive mode);
   735 
   736 
   737 *** HOL ***
   738 
   739 * arith(_tac)
   740 
   741  - Produces a counter example if it cannot prove a goal.
   742    Note that the counter example may be spurious if the goal is not a formula
   743    of quantifier-free linear arithmetic.
   744    In ProofGeneral the counter example appears in the trace buffer.
   745 
   746  - Knows about div k and mod k where k is a numeral of type nat or int.
   747 
   748  - Calls full Presburger arithmetic (by Amine Chaieb) if quantifier-free
   749    linear arithmetic fails. This takes account of quantifiers and divisibility.
   750    Presburger arithmetic can also be called explicitly via presburger(_tac).
   751 
   752 * simp's arithmetic capabilities have been enhanced a bit: it now
   753 takes ~= in premises into account (by performing a case split);
   754 
   755 * simp reduces "m*(n div m) + n mod m" to n, even if the two summands
   756 are distributed over a sum of terms;
   757 
   758 * New tactic "trans_tac" and method "trans" instantiate
   759 Provers/linorder.ML for axclasses "order" and "linorder" (predicates
   760 "<=", "<" and "=").
   761 
   762 * function INCOMPATIBILITIES: Pi-sets have been redefined and moved from main
   763 HOL to Library/FuncSet; constant "Fun.op o" is now called "Fun.comp";
   764 
   765 * 'typedef' command has new option "open" to suppress the set
   766 definition;
   767 
   768 * functions Min and Max on finite sets have been introduced (theory
   769 Finite_Set);
   770 
   771 * attribute [symmetric] now works for relations as well; it turns
   772 (x,y) : R^-1 into (y,x) : R, and vice versa;
   773 
   774 * induct over a !!-quantified statement (say !!x1..xn):
   775   each "case" automatically performs "fix x1 .. xn" with exactly those names.
   776 
   777 * Map: `empty' is no longer a constant but a syntactic abbreviation for
   778 %x. None. Warning: empty_def now refers to the previously hidden definition
   779 of the empty set.
   780 
   781 * Algebra: formalization of classical algebra.  Intended as base for
   782 any algebraic development in Isabelle.  Currently covers group theory
   783 (up to Sylow's theorem) and ring theory (Universal Property of
   784 Univariate Polynomials).  Contributions welcome;
   785 
   786 * GroupTheory: deleted, since its material has been moved to Algebra;
   787 
   788 * Complex: new directory of the complex numbers with numeric constants,
   789 nonstandard complex numbers, and some complex analysis, standard and
   790 nonstandard (Jacques Fleuriot);
   791 
   792 * HOL-Complex: new image for analysis, replacing HOL-Real and HOL-Hyperreal;
   793 
   794 * Hyperreal: introduced Gauge integration and hyperreal logarithms (Jacques
   795 Fleuriot);
   796 
   797 * Real/HahnBanach: updated and adapted to locales;
   798 
   799 * NumberTheory: added Gauss's law of quadratic reciprocity (by Avigad,
   800 Gray and Kramer);
   801 
   802 * UNITY: added the Meier-Sanders theory of progress sets;
   803 
   804 * MicroJava: bytecode verifier and lightweight bytecode verifier
   805 as abstract algorithms, instantiated to the JVM;
   806 
   807 * Bali: Java source language formalization. Type system, operational
   808 semantics, axiomatic semantics. Supported language features:
   809 classes, interfaces, objects,virtual methods, static methods,
   810 static/instance fields, arrays, access modifiers, definite
   811 assignment, exceptions.
   812 
   813 
   814 *** ZF ***
   815 
   816 * ZF/Constructible: consistency proof for AC (Gdel's constructible
   817 universe, etc.);
   818 
   819 * Main ZF: virtually all theories converted to new-style format;
   820 
   821 
   822 *** ML ***
   823 
   824 * Pure: Tactic.prove provides sane interface for internal proofs;
   825 omits the infamous "standard" operation, so this is more appropriate
   826 than prove_goalw_cterm in many situations (e.g. in simprocs);
   827 
   828 * Pure: improved error reporting of simprocs;
   829 
   830 * Provers: Simplifier.simproc(_i) provides sane interface for setting
   831 up simprocs;
   832 
   833 
   834 *** Document preparation ***
   835 
   836 * uses \par instead of \\ for line breaks in theory text. This may
   837 shift some page breaks in large documents. To get the old behaviour
   838 use \renewcommand{\isanewline}{\mbox{}\\\mbox{}} in root.tex.
   839 
   840 * minimized dependencies of isabelle.sty and isabellesym.sty on
   841 other packages
   842 
   843 * \<euro> now needs package babel/greek instead of marvosym (which
   844 broke \Rightarrow)
   845 
   846 * normal size for \<zero>...\<nine> (uses \mathbf instead of
   847 textcomp package)
   848 
   849 
   850 
   851 New in Isabelle2002 (March 2002)
   852 --------------------------------
   853 
   854 *** Document preparation ***
   855 
   856 * greatly simplified document preparation setup, including more
   857 graceful interpretation of isatool usedir -i/-d/-D options, and more
   858 instructive isatool mkdir; users should basically be able to get
   859 started with "isatool mkdir HOL Test && isatool make"; alternatively,
   860 users may run a separate document processing stage manually like this:
   861 "isatool usedir -D output HOL Test && isatool document Test/output";
   862 
   863 * theory dependency graph may now be incorporated into documents;
   864 isatool usedir -g true will produce session_graph.eps/.pdf for use
   865 with \includegraphics of LaTeX;
   866 
   867 * proper spacing of consecutive markup elements, especially text
   868 blocks after section headings;
   869 
   870 * support bold style (for single symbols only), input syntax is like
   871 this: "\<^bold>\<alpha>" or "\<^bold>A";
   872 
   873 * \<bullet> is now output as bold \cdot by default, which looks much
   874 better in printed text;
   875 
   876 * added default LaTeX bindings for \<tturnstile> and \<TTurnstile>;
   877 note that these symbols are currently unavailable in Proof General /
   878 X-Symbol; new symbols \<zero>, \<one>, ..., \<nine>, and \<euro>;
   879 
   880 * isatool latex no longer depends on changed TEXINPUTS, instead
   881 isatool document copies the Isabelle style files to the target
   882 location;
   883 
   884 
   885 *** Isar ***
   886 
   887 * Pure/Provers: improved proof by cases and induction;
   888   - 'case' command admits impromptu naming of parameters (such as
   889     "case (Suc n)");
   890   - 'induct' method divinates rule instantiation from the inductive
   891     claim; no longer requires excessive ?P bindings for proper
   892     instantiation of cases;
   893   - 'induct' method properly enumerates all possibilities of set/type
   894     rules; as a consequence facts may be also passed through *type*
   895     rules without further ado;
   896   - 'induct' method now derives symbolic cases from the *rulified*
   897     rule (before it used to rulify cases stemming from the internal
   898     atomized version); this means that the context of a non-atomic
   899     statement becomes is included in the hypothesis, avoiding the
   900     slightly cumbersome show "PROP ?case" form;
   901   - 'induct' may now use elim-style induction rules without chaining
   902     facts, using ``missing'' premises from the goal state; this allows
   903     rules stemming from inductive sets to be applied in unstructured
   904     scripts, while still benefitting from proper handling of non-atomic
   905     statements; NB: major inductive premises need to be put first, all
   906     the rest of the goal is passed through the induction;
   907   - 'induct' proper support for mutual induction involving non-atomic
   908     rule statements (uses the new concept of simultaneous goals, see
   909     below);
   910   - append all possible rule selections, but only use the first
   911     success (no backtracking);
   912   - removed obsolete "(simplified)" and "(stripped)" options of methods;
   913   - undeclared rule case names default to numbers 1, 2, 3, ...;
   914   - added 'print_induct_rules' (covered by help item in recent Proof
   915     General versions);
   916   - moved induct/cases attributes to Pure, methods to Provers;
   917   - generic method setup instantiated for FOL and HOL;
   918 
   919 * Pure: support multiple simultaneous goal statements, for example
   920 "have a: A and b: B" (same for 'theorem' etc.); being a pure
   921 meta-level mechanism, this acts as if several individual goals had
   922 been stated separately; in particular common proof methods need to be
   923 repeated in order to cover all claims; note that a single elimination
   924 step is *not* sufficient to establish the two conjunctions, so this
   925 fails:
   926 
   927   assume "A & B" then have A and B ..   (*".." fails*)
   928 
   929 better use "obtain" in situations as above; alternative refer to
   930 multi-step methods like 'auto', 'simp_all', 'blast+' etc.;
   931 
   932 * Pure: proper integration with ``locales''; unlike the original
   933 version by Florian Kammller, Isar locales package high-level proof
   934 contexts rather than raw logical ones (e.g. we admit to include
   935 attributes everywhere); operations on locales include merge and
   936 rename; support for implicit arguments (``structures''); simultaneous
   937 type-inference over imports and text; see also HOL/ex/Locales.thy for
   938 some examples;
   939 
   940 * Pure: the following commands have been ``localized'', supporting a
   941 target locale specification "(in name)": 'lemma', 'theorem',
   942 'corollary', 'lemmas', 'theorems', 'declare'; the results will be
   943 stored both within the locale and at the theory level (exported and
   944 qualified by the locale name);
   945 
   946 * Pure: theory goals may now be specified in ``long'' form, with
   947 ad-hoc contexts consisting of arbitrary locale elements. for example
   948 ``lemma foo: fixes x assumes "A x" shows "B x"'' (local syntax and
   949 definitions may be given, too); the result is a meta-level rule with
   950 the context elements being discharged in the obvious way;
   951 
   952 * Pure: new proof command 'using' allows to augment currently used
   953 facts after a goal statement ('using' is syntactically analogous to
   954 'apply', but acts on the goal's facts only); this allows chained facts
   955 to be separated into parts given before and after a claim, as in
   956 ``from a and b have C using d and e <proof>'';
   957 
   958 * Pure: renamed "antecedent" case to "rule_context";
   959 
   960 * Pure: new 'judgment' command records explicit information about the
   961 object-logic embedding (used by several tools internally); no longer
   962 use hard-wired "Trueprop";
   963 
   964 * Pure: added 'corollary' command;
   965 
   966 * Pure: fixed 'token_translation' command;
   967 
   968 * Pure: removed obsolete 'exported' attribute;
   969 
   970 * Pure: dummy pattern "_" in is/let is now automatically lifted over
   971 bound variables: "ALL x. P x --> Q x" (is "ALL x. _ --> ?C x")
   972 supersedes more cumbersome ... (is "ALL x. _ x --> ?C x");
   973 
   974 * Pure: method 'atomize' presents local goal premises as object-level
   975 statements (atomic meta-level propositions); setup controlled via
   976 rewrite rules declarations of 'atomize' attribute; example
   977 application: 'induct' method with proper rule statements in improper
   978 proof *scripts*;
   979 
   980 * Pure: emulation of instantiation tactics (rule_tac, cut_tac, etc.)
   981 now consider the syntactic context of assumptions, giving a better
   982 chance to get type-inference of the arguments right (this is
   983 especially important for locales);
   984 
   985 * Pure: "sorry" no longer requires quick_and_dirty in interactive
   986 mode;
   987 
   988 * Pure/obtain: the formal conclusion "thesis", being marked as
   989 ``internal'', may no longer be reference directly in the text;
   990 potential INCOMPATIBILITY, may need to use "?thesis" in rare
   991 situations;
   992 
   993 * Pure: generic 'sym' attribute which declares a rule both as pure
   994 'elim?' and for the 'symmetric' operation;
   995 
   996 * Pure: marginal comments ``--'' may now occur just anywhere in the
   997 text; the fixed correlation with particular command syntax has been
   998 discontinued;
   999 
  1000 * Pure: new method 'rules' is particularly well-suited for proof
  1001 search in intuitionistic logic; a bit slower than 'blast' or 'fast',
  1002 but often produces more compact proof terms with less detours;
  1003 
  1004 * Pure/Provers/classical: simplified integration with pure rule
  1005 attributes and methods; the classical "intro?/elim?/dest?"
  1006 declarations coincide with the pure ones; the "rule" method no longer
  1007 includes classically swapped intros; "intro" and "elim" methods no
  1008 longer pick rules from the context; also got rid of ML declarations
  1009 AddXIs/AddXEs/AddXDs; all of this has some potential for
  1010 INCOMPATIBILITY;
  1011 
  1012 * Provers/classical: attribute 'swapped' produces classical inversions
  1013 of introduction rules;
  1014 
  1015 * Provers/simplifier: 'simplified' attribute may refer to explicit
  1016 rules instead of full simplifier context; 'iff' attribute handles
  1017 conditional rules;
  1018 
  1019 * HOL: 'typedef' now allows alternative names for Rep/Abs morphisms;
  1020 
  1021 * HOL: 'recdef' now fails on unfinished automated proofs, use
  1022 "(permissive)" option to recover old behavior;
  1023 
  1024 * HOL: 'inductive' no longer features separate (collective) attributes
  1025 for 'intros' (was found too confusing);
  1026 
  1027 * HOL: properly declared induction rules less_induct and
  1028 wf_induct_rule;
  1029 
  1030 
  1031 *** HOL ***
  1032 
  1033 * HOL: moved over to sane numeral syntax; the new policy is as
  1034 follows:
  1035 
  1036   - 0 and 1 are polymorphic constants, which are defined on any
  1037   numeric type (nat, int, real etc.);
  1038 
  1039   - 2, 3, 4, ... and -1, -2, -3, ... are polymorphic numerals, based
  1040   binary representation internally;
  1041 
  1042   - type nat has special constructor Suc, and generally prefers Suc 0
  1043   over 1::nat and Suc (Suc 0) over 2::nat;
  1044 
  1045 This change may cause significant problems of INCOMPATIBILITY; here
  1046 are some hints on converting existing sources:
  1047 
  1048   - due to the new "num" token, "-0" and "-1" etc. are now atomic
  1049   entities, so expressions involving "-" (unary or binary minus) need
  1050   to be spaced properly;
  1051 
  1052   - existing occurrences of "1" may need to be constraint "1::nat" or
  1053   even replaced by Suc 0; similar for old "2";
  1054 
  1055   - replace "#nnn" by "nnn", and "#-nnn" by "-nnn";
  1056 
  1057   - remove all special provisions on numerals in proofs;
  1058 
  1059 * HOL: simp rules nat_number expand numerals on nat to Suc/0
  1060 representation (depends on bin_arith_simps in the default context);
  1061 
  1062 * HOL: symbolic syntax for x^2 (numeral 2);
  1063 
  1064 * HOL: the class of all HOL types is now called "type" rather than
  1065 "term"; INCOMPATIBILITY, need to adapt references to this type class
  1066 in axclass/classes, instance/arities, and (usually rare) occurrences
  1067 in typings (of consts etc.); internally the class is called
  1068 "HOL.type", ML programs should refer to HOLogic.typeS;
  1069 
  1070 * HOL/record package improvements:
  1071   - new derived operations "fields" to build a partial record section,
  1072     "extend" to promote a fixed record to a record scheme, and
  1073     "truncate" for the reverse; cf. theorems "xxx.defs", which are *not*
  1074     declared as simp by default;
  1075   - shared operations ("more", "fields", etc.) now need to be always
  1076     qualified) --- potential INCOMPATIBILITY;
  1077   - removed "make_scheme" operations (use "make" with "extend") --
  1078     INCOMPATIBILITY;
  1079   - removed "more" class (simply use "term") -- INCOMPATIBILITY;
  1080   - provides cases/induct rules for use with corresponding Isar
  1081     methods (for concrete records, record schemes, concrete more
  1082     parts, and schematic more parts -- in that order);
  1083   - internal definitions directly based on a light-weight abstract
  1084     theory of product types over typedef rather than datatype;
  1085 
  1086 * HOL: generic code generator for generating executable ML code from
  1087 specifications; specific support for HOL constructs such as inductive
  1088 datatypes and sets, as well as recursive functions; can be invoked
  1089 via 'generate_code' theory section;
  1090 
  1091 * HOL: canonical cases/induct rules for n-tuples (n = 3..7);
  1092 
  1093 * HOL: consolidated and renamed several theories.  In particular:
  1094         Ord.thy has been absorbed into HOL.thy
  1095         String.thy has been absorbed into List.thy
  1096 
  1097 * HOL: concrete setsum syntax "\<Sum>i:A. b" == "setsum (%i. b) A"
  1098 (beware of argument permutation!);
  1099 
  1100 * HOL: linorder_less_split superseded by linorder_cases;
  1101 
  1102 * HOL/List: "nodups" renamed to "distinct";
  1103 
  1104 * HOL: added "The" definite description operator; move Hilbert's "Eps"
  1105 to peripheral theory "Hilbert_Choice"; some INCOMPATIBILITIES:
  1106   - Ex_def has changed, now need to use some_eq_ex
  1107 
  1108 * HOL: made split_all_tac safe; EXISTING PROOFS MAY FAIL OR LOOP, so
  1109 in this (rare) case use:
  1110 
  1111   delSWrapper "split_all_tac"
  1112   addSbefore ("unsafe_split_all_tac", unsafe_split_all_tac)
  1113 
  1114 * HOL: added safe wrapper "split_conv_tac" to claset; EXISTING PROOFS
  1115 MAY FAIL;
  1116 
  1117 * HOL: introduced f^n = f o ... o f; warning: due to the limits of
  1118 Isabelle's type classes, ^ on functions and relations has too general
  1119 a domain, namely ('a * 'b) set and 'a => 'b; this means that it may be
  1120 necessary to attach explicit type constraints;
  1121 
  1122 * HOL/Relation: the prefix name of the infix "O" has been changed from
  1123 "comp" to "rel_comp"; INCOMPATIBILITY: a few theorems have been
  1124 renamed accordingly (eg "compI" -> "rel_compI").
  1125 
  1126 * HOL: syntax translations now work properly with numerals and records
  1127 expressions;
  1128 
  1129 * HOL: bounded abstraction now uses syntax "%" / "\<lambda>" instead
  1130 of "lam" -- INCOMPATIBILITY;
  1131 
  1132 * HOL: got rid of some global declarations (potential INCOMPATIBILITY
  1133 for ML tools): const "()" renamed "Product_Type.Unity", type "unit"
  1134 renamed "Product_Type.unit";
  1135 
  1136 * HOL: renamed rtrancl_into_rtrancl2 to converse_rtrancl_into_rtrancl
  1137 
  1138 * HOL: removed obsolete theorem "optionE" (use "option.exhaust", or
  1139 the "cases" method);
  1140 
  1141 * HOL/GroupTheory: group theory examples including Sylow's theorem (by
  1142 Florian Kammller);
  1143 
  1144 * HOL/IMP: updated and converted to new-style theory format; several
  1145 parts turned into readable document, with proper Isar proof texts and
  1146 some explanations (by Gerwin Klein);
  1147 
  1148 * HOL-Real: added Complex_Numbers (by Gertrud Bauer);
  1149 
  1150 * HOL-Hyperreal is now a logic image;
  1151 
  1152 
  1153 *** HOLCF ***
  1154 
  1155 * Isar: consts/constdefs supports mixfix syntax for continuous
  1156 operations;
  1157 
  1158 * Isar: domain package adapted to new-style theory format, e.g. see
  1159 HOLCF/ex/Dnat.thy;
  1160 
  1161 * theory Lift: proper use of rep_datatype lift instead of ML hacks --
  1162 potential INCOMPATIBILITY; now use plain induct_tac instead of former
  1163 lift.induct_tac, always use UU instead of Undef;
  1164 
  1165 * HOLCF/IMP: updated and converted to new-style theory;
  1166 
  1167 
  1168 *** ZF ***
  1169 
  1170 * Isar: proper integration of logic-specific tools and packages,
  1171 including theory commands '(co)inductive', '(co)datatype',
  1172 'rep_datatype', 'inductive_cases', as well as methods 'ind_cases',
  1173 'induct_tac', 'case_tac', and 'typecheck' (with attribute 'TC');
  1174 
  1175 * theory Main no longer includes AC; for the Axiom of Choice, base
  1176 your theory on Main_ZFC;
  1177 
  1178 * the integer library now covers quotients and remainders, with many
  1179 laws relating division to addition, multiplication, etc.;
  1180 
  1181 * ZF/UNITY: Chandy and Misra's UNITY is now available in ZF, giving a
  1182 typeless version of the formalism;
  1183 
  1184 * ZF/AC, Coind, IMP, Resid: updated and converted to new-style theory
  1185 format;
  1186 
  1187 * ZF/Induct: new directory for examples of inductive definitions,
  1188 including theory Multiset for multiset orderings; converted to
  1189 new-style theory format;
  1190 
  1191 * ZF: many new theorems about lists, ordinals, etc.;
  1192 
  1193 
  1194 *** General ***
  1195 
  1196 * Pure/kernel: meta-level proof terms (by Stefan Berghofer); reference
  1197 variable proof controls level of detail: 0 = no proofs (only oracle
  1198 dependencies), 1 = lemma dependencies, 2 = compact proof terms; see
  1199 also ref manual for further ML interfaces;
  1200 
  1201 * Pure/axclass: removed obsolete ML interface
  1202 goal_subclass/goal_arity;
  1203 
  1204 * Pure/syntax: new token syntax "num" for plain numerals (without "#"
  1205 of "xnum"); potential INCOMPATIBILITY, since -0, -1 etc. are now
  1206 separate tokens, so expressions involving minus need to be spaced
  1207 properly;
  1208 
  1209 * Pure/syntax: support non-oriented infixes, using keyword "infix"
  1210 rather than "infixl" or "infixr";
  1211 
  1212 * Pure/syntax: concrete syntax for dummy type variables admits genuine
  1213 sort constraint specifications in type inference; e.g. "x::_::foo"
  1214 ensures that the type of "x" is of sort "foo" (but not necessarily a
  1215 type variable);
  1216 
  1217 * Pure/syntax: print modes "type_brackets" and "no_type_brackets"
  1218 control output of nested => (types); the default behavior is
  1219 "type_brackets";
  1220 
  1221 * Pure/syntax: builtin parse translation for "_constify" turns valued
  1222 tokens into AST constants;
  1223 
  1224 * Pure/syntax: prefer later declarations of translations and print
  1225 translation functions; potential INCOMPATIBILITY: need to reverse
  1226 multiple declarations for same syntax element constant;
  1227 
  1228 * Pure/show_hyps reset by default (in accordance to existing Isar
  1229 practice);
  1230 
  1231 * Provers/classical: renamed addaltern to addafter, addSaltern to
  1232 addSafter;
  1233 
  1234 * Provers/clasimp: ``iff'' declarations now handle conditional rules
  1235 as well;
  1236 
  1237 * system: tested support for MacOS X; should be able to get Isabelle +
  1238 Proof General to work in a plain Terminal after installing Poly/ML
  1239 (e.g. from the Isabelle distribution area) and GNU bash alone
  1240 (e.g. from http://www.apple.com); full X11, XEmacs and X-Symbol
  1241 support requires further installations, e.g. from
  1242 http://fink.sourceforge.net/);
  1243 
  1244 * system: support Poly/ML 4.1.1 (able to manage larger heaps);
  1245 
  1246 * system: reduced base memory usage by Poly/ML (approx. 20 MB instead
  1247 of 40 MB), cf. ML_OPTIONS;
  1248 
  1249 * system: Proof General keywords specification is now part of the
  1250 Isabelle distribution (see etc/isar-keywords.el);
  1251 
  1252 * system: support for persistent Proof General sessions (refrain from
  1253 outdating all loaded theories on startup); user may create writable
  1254 logic images like this: ``isabelle -q HOL Test'';
  1255 
  1256 * system: smart selection of Isabelle process versus Isabelle
  1257 interface, accommodates case-insensitive file systems (e.g. HFS+); may
  1258 run both "isabelle" and "Isabelle" even if file names are badly
  1259 damaged (executable inspects the case of the first letter of its own
  1260 name); added separate "isabelle-process" and "isabelle-interface";
  1261 
  1262 * system: refrain from any attempt at filtering input streams; no
  1263 longer support ``8bit'' encoding of old isabelle font, instead proper
  1264 iso-latin characters may now be used; the related isatools
  1265 "symbolinput" and "nonascii" have disappeared as well;
  1266 
  1267 * system: removed old "xterm" interface (the print modes "xterm" and
  1268 "xterm_color" are still available for direct use in a suitable
  1269 terminal);
  1270 
  1271 
  1272 
  1273 New in Isabelle99-2 (February 2001)
  1274 -----------------------------------
  1275 
  1276 *** Overview of INCOMPATIBILITIES ***
  1277 
  1278 * HOL: please note that theories in the Library and elsewhere often use the
  1279 new-style (Isar) format; to refer to their theorems in an ML script you must
  1280 bind them to ML identifers by e.g.      val thm_name = thm "thm_name";
  1281 
  1282 * HOL: inductive package no longer splits induction rule aggressively,
  1283 but only as far as specified by the introductions given; the old
  1284 format may be recovered via ML function complete_split_rule or attribute
  1285 'split_rule (complete)';
  1286 
  1287 * HOL: induct renamed to lfp_induct, lfp_Tarski to lfp_unfold,
  1288 gfp_Tarski to gfp_unfold;
  1289 
  1290 * HOL: contrapos, contrapos2 renamed to contrapos_nn, contrapos_pp;
  1291 
  1292 * HOL: infix "dvd" now has priority 50 rather than 70 (because it is a
  1293 relation); infix "^^" has been renamed "``"; infix "``" has been
  1294 renamed "`"; "univalent" has been renamed "single_valued";
  1295 
  1296 * HOL/Real: "rinv" and "hrinv" replaced by overloaded "inverse"
  1297 operation;
  1298 
  1299 * HOLCF: infix "`" has been renamed "$"; the symbol syntax is \<cdot>;
  1300 
  1301 * Isar: 'obtain' no longer declares "that" fact as simp/intro;
  1302 
  1303 * Isar/HOL: method 'induct' now handles non-atomic goals; as a
  1304 consequence, it is no longer monotonic wrt. the local goal context
  1305 (which is now passed through the inductive cases);
  1306 
  1307 * Document preparation: renamed standard symbols \<ll> to \<lless> and
  1308 \<gg> to \<ggreater>;
  1309 
  1310 
  1311 *** Document preparation ***
  1312 
  1313 * \isabellestyle{NAME} selects version of Isabelle output (currently
  1314 available: are "it" for near math-mode best-style output, "sl" for
  1315 slanted text style, and "tt" for plain type-writer; if no
  1316 \isabellestyle command is given, output is according to slanted
  1317 type-writer);
  1318 
  1319 * support sub/super scripts (for single symbols only), input syntax is
  1320 like this: "A\<^sup>*" or "A\<^sup>\<star>";
  1321 
  1322 * some more standard symbols; see Appendix A of the system manual for
  1323 the complete list of symbols defined in isabellesym.sty;
  1324 
  1325 * improved isabelle style files; more abstract symbol implementation
  1326 (should now use \isamath{...} and \isatext{...} in custom symbol
  1327 definitions);
  1328 
  1329 * antiquotation @{goals} and @{subgoals} for output of *dynamic* goals
  1330 state; Note that presentation of goal states does not conform to
  1331 actual human-readable proof documents.  Please do not include goal
  1332 states into document output unless you really know what you are doing!
  1333 
  1334 * proper indentation of antiquoted output with proportional LaTeX
  1335 fonts;
  1336 
  1337 * no_document ML operator temporarily disables LaTeX document
  1338 generation;
  1339 
  1340 * isatool unsymbolize tunes sources for plain ASCII communication;
  1341 
  1342 
  1343 *** Isar ***
  1344 
  1345 * Pure: Isar now suffers initial goal statements to contain unbound
  1346 schematic variables (this does not conform to actual readable proof
  1347 documents, due to unpredictable outcome and non-compositional proof
  1348 checking); users who know what they are doing may use schematic goals
  1349 for Prolog-style synthesis of proven results;
  1350 
  1351 * Pure: assumption method (an implicit finishing) now handles actual
  1352 rules as well;
  1353 
  1354 * Pure: improved 'obtain' --- moved to Pure, insert "that" into
  1355 initial goal, declare "that" only as Pure intro (only for single
  1356 steps); the "that" rule assumption may now be involved in implicit
  1357 finishing, thus ".." becomes a feasible for trivial obtains;
  1358 
  1359 * Pure: default proof step now includes 'intro_classes'; thus trivial
  1360 instance proofs may be performed by "..";
  1361 
  1362 * Pure: ?thesis / ?this / "..." now work for pure meta-level
  1363 statements as well;
  1364 
  1365 * Pure: more robust selection of calculational rules;
  1366 
  1367 * Pure: the builtin notion of 'finished' goal now includes the ==-refl
  1368 rule (as well as the assumption rule);
  1369 
  1370 * Pure: 'thm_deps' command visualizes dependencies of theorems and
  1371 lemmas, using the graph browser tool;
  1372 
  1373 * Pure: predict failure of "show" in interactive mode;
  1374 
  1375 * Pure: 'thms_containing' now takes actual terms as arguments;
  1376 
  1377 * HOL: improved method 'induct' --- now handles non-atomic goals
  1378 (potential INCOMPATIBILITY); tuned error handling;
  1379 
  1380 * HOL: cases and induct rules now provide explicit hints about the
  1381 number of facts to be consumed (0 for "type" and 1 for "set" rules);
  1382 any remaining facts are inserted into the goal verbatim;
  1383 
  1384 * HOL: local contexts (aka cases) may now contain term bindings as
  1385 well; the 'cases' and 'induct' methods new provide a ?case binding for
  1386 the result to be shown in each case;
  1387 
  1388 * HOL: added 'recdef_tc' command;
  1389 
  1390 * isatool convert assists in eliminating legacy ML scripts;
  1391 
  1392 
  1393 *** HOL ***
  1394 
  1395 * HOL/Library: a collection of generic theories to be used together
  1396 with main HOL; the theory loader path already includes this directory
  1397 by default; the following existing theories have been moved here:
  1398 HOL/Induct/Multiset, HOL/Induct/Acc (as Accessible_Part), HOL/While
  1399 (as While_Combinator), HOL/Lex/Prefix (as List_Prefix);
  1400 
  1401 * HOL/Unix: "Some aspects of Unix file-system security", a typical
  1402 modelling and verification task performed in Isabelle/HOL +
  1403 Isabelle/Isar + Isabelle document preparation (by Markus Wenzel).
  1404 
  1405 * HOL/Algebra: special summation operator SUM no longer exists, it has
  1406 been replaced by setsum; infix 'assoc' now has priority 50 (like
  1407 'dvd'); axiom 'one_not_zero' has been moved from axclass 'ring' to
  1408 'domain', this makes the theory consistent with mathematical
  1409 literature;
  1410 
  1411 * HOL basics: added overloaded operations "inverse" and "divide"
  1412 (infix "/"), syntax for generic "abs" operation, generic summation
  1413 operator \<Sum>;
  1414 
  1415 * HOL/typedef: simplified package, provide more useful rules (see also
  1416 HOL/subset.thy);
  1417 
  1418 * HOL/datatype: induction rule for arbitrarily branching datatypes is
  1419 now expressed as a proper nested rule (old-style tactic scripts may
  1420 require atomize_strip_tac to cope with non-atomic premises);
  1421 
  1422 * HOL: renamed theory "Prod" to "Product_Type", renamed "split" rule
  1423 to "split_conv" (old name still available for compatibility);
  1424 
  1425 * HOL: improved concrete syntax for strings (e.g. allows translation
  1426 rules with string literals);
  1427 
  1428 * HOL-Real-Hyperreal: this extends HOL-Real with the hyperreals
  1429  and Fleuriot's mechanization of analysis, including the transcendental
  1430  functions for the reals;
  1431 
  1432 * HOL/Real, HOL/Hyperreal: improved arithmetic simplification;
  1433 
  1434 
  1435 *** CTT ***
  1436 
  1437 * CTT: x-symbol support for Pi, Sigma, -->, : (membership); note that
  1438 "lam" is displayed as TWO lambda-symbols
  1439 
  1440 * CTT: theory Main now available, containing everything (that is, Bool
  1441 and Arith);
  1442 
  1443 
  1444 *** General ***
  1445 
  1446 * Pure: the Simplifier has been implemented properly as a derived rule
  1447 outside of the actual kernel (at last!); the overall performance
  1448 penalty in practical applications is about 50%, while reliability of
  1449 the Isabelle inference kernel has been greatly improved;
  1450 
  1451 * print modes "brackets" and "no_brackets" control output of nested =>
  1452 (types) and ==> (props); the default behaviour is "brackets";
  1453 
  1454 * Provers: fast_tac (and friends) now handle actual object-logic rules
  1455 as assumptions as well;
  1456 
  1457 * system: support Poly/ML 4.0;
  1458 
  1459 * system: isatool install handles KDE version 1 or 2;
  1460 
  1461 
  1462 
  1463 New in Isabelle99-1 (October 2000)
  1464 ----------------------------------
  1465 
  1466 *** Overview of INCOMPATIBILITIES ***
  1467 
  1468 * HOL: simplification of natural numbers is much changed; to partly
  1469 recover the old behaviour (e.g. to prevent n+n rewriting to #2*n)
  1470 issue the following ML commands:
  1471 
  1472   Delsimprocs Nat_Numeral_Simprocs.cancel_numerals;
  1473   Delsimprocs [Nat_Numeral_Simprocs.combine_numerals];
  1474 
  1475 * HOL: simplification no longer dives into case-expressions; this is
  1476 controlled by "t.weak_case_cong" for each datatype t;
  1477 
  1478 * HOL: nat_less_induct renamed to less_induct;
  1479 
  1480 * HOL: systematic renaming of the SOME (Eps) rules, may use isatool
  1481 fixsome to patch .thy and .ML sources automatically;
  1482 
  1483   select_equality  -> some_equality
  1484   select_eq_Ex     -> some_eq_ex
  1485   selectI2EX       -> someI2_ex
  1486   selectI2         -> someI2
  1487   selectI          -> someI
  1488   select1_equality -> some1_equality
  1489   Eps_sym_eq       -> some_sym_eq_trivial
  1490   Eps_eq           -> some_eq_trivial
  1491 
  1492 * HOL: exhaust_tac on datatypes superceded by new generic case_tac;
  1493 
  1494 * HOL: removed obsolete theorem binding expand_if (refer to split_if
  1495 instead);
  1496 
  1497 * HOL: the recursion equations generated by 'recdef' are now called
  1498 f.simps instead of f.rules;
  1499 
  1500 * HOL: qed_spec_mp now also handles bounded ALL as well;
  1501 
  1502 * HOL: 0 is now overloaded, so the type constraint ":: nat" may
  1503 sometimes be needed;
  1504 
  1505 * HOL: the constant for "f``x" is now "image" rather than "op ``";
  1506 
  1507 * HOL: the constant for "f-``x" is now "vimage" rather than "op -``";
  1508 
  1509 * HOL: the disjoint sum is now "<+>" instead of "Plus"; the cartesian
  1510 product is now "<*>" instead of "Times"; the lexicographic product is
  1511 now "<*lex*>" instead of "**";
  1512 
  1513 * HOL: theory Sexp is now in HOL/Induct examples (it used to be part
  1514 of main HOL, but was unused); better use HOL's datatype package;
  1515 
  1516 * HOL: removed "symbols" syntax for constant "override" of theory Map;
  1517 the old syntax may be recovered as follows:
  1518 
  1519   syntax (symbols)
  1520     override  :: "('a ~=> 'b) => ('a ~=> 'b) => ('a ~=> 'b)"
  1521       (infixl "\\<oplus>" 100)
  1522 
  1523 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1524 
  1525 * HOL/ML: even fewer consts are declared as global (see theories Ord,
  1526 Lfp, Gfp, WF); this only affects ML packages that refer to const names
  1527 internally;
  1528 
  1529 * HOL and ZF: syntax for quotienting wrt an equivalence relation
  1530 changed from A/r to A//r;
  1531 
  1532 * ZF: new treatment of arithmetic (nat & int) may break some old
  1533 proofs;
  1534 
  1535 * Isar: renamed some attributes (RS -> THEN, simplify -> simplified,
  1536 rulify -> rule_format, elimify -> elim_format, ...);
  1537 
  1538 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1539 intro/intro!/intro!! flags to intro!/intro/intro? (in most cases, one
  1540 should have to change intro!! to intro? only); replaced "delrule" by
  1541 "rule del";
  1542 
  1543 * Isar/HOL: renamed "intrs" to "intros" in inductive definitions;
  1544 
  1545 * Provers: strengthened force_tac by using new first_best_tac;
  1546 
  1547 * LaTeX document preparation: several changes of isabelle.sty (see
  1548 lib/texinputs);
  1549 
  1550 
  1551 *** Document preparation ***
  1552 
  1553 * formal comments (text blocks etc.) in new-style theories may now
  1554 contain antiquotations of thm/prop/term/typ/text to be presented
  1555 according to latex print mode; concrete syntax is like this:
  1556 @{term[show_types] "f(x) = a + x"};
  1557 
  1558 * isatool mkdir provides easy setup of Isabelle session directories,
  1559 including proper document sources;
  1560 
  1561 * generated LaTeX sources are now deleted after successful run
  1562 (isatool document -c); may retain a copy somewhere else via -D option
  1563 of isatool usedir;
  1564 
  1565 * isatool usedir -D now lets isatool latex -o sty update the Isabelle
  1566 style files, achieving self-contained LaTeX sources and simplifying
  1567 LaTeX debugging;
  1568 
  1569 * old-style theories now produce (crude) LaTeX output as well;
  1570 
  1571 * browser info session directories are now self-contained (may be put
  1572 on WWW server seperately); improved graphs of nested sessions; removed
  1573 graph for 'all sessions';
  1574 
  1575 * several improvements in isabelle style files; \isabellestyle{it}
  1576 produces fake math mode output; \isamarkupheader is now \section by
  1577 default; see lib/texinputs/isabelle.sty etc.;
  1578 
  1579 
  1580 *** Isar ***
  1581 
  1582 * Isar/Pure: local results and corresponding term bindings are now
  1583 subject to Hindley-Milner polymorphism (similar to ML); this
  1584 accommodates incremental type-inference very nicely;
  1585 
  1586 * Isar/Pure: new derived language element 'obtain' supports
  1587 generalized existence reasoning;
  1588 
  1589 * Isar/Pure: new calculational elements 'moreover' and 'ultimately'
  1590 support accumulation of results, without applying any rules yet;
  1591 useful to collect intermediate results without explicit name
  1592 references, and for use with transitivity rules with more than 2
  1593 premises;
  1594 
  1595 * Isar/Pure: scalable support for case-analysis type proofs: new
  1596 'case' language element refers to local contexts symbolically, as
  1597 produced by certain proof methods; internally, case names are attached
  1598 to theorems as "tags";
  1599 
  1600 * Isar/Pure: theory command 'hide' removes declarations from
  1601 class/type/const name spaces;
  1602 
  1603 * Isar/Pure: theory command 'defs' supports option "(overloaded)" to
  1604 indicate potential overloading;
  1605 
  1606 * Isar/Pure: changed syntax of local blocks from {{ }} to { };
  1607 
  1608 * Isar/Pure: syntax of sorts made 'inner', i.e. have to write
  1609 "{a,b,c}" instead of {a,b,c};
  1610 
  1611 * Isar/Pure now provides its own version of intro/elim/dest
  1612 attributes; useful for building new logics, but beware of confusion
  1613 with the version in Provers/classical;
  1614 
  1615 * Isar/Pure: the local context of (non-atomic) goals is provided via
  1616 case name 'antecedent';
  1617 
  1618 * Isar/Pure: removed obsolete 'transfer' attribute (transfer of thms
  1619 to the current context is now done automatically);
  1620 
  1621 * Isar/Pure: theory command 'method_setup' provides a simple interface
  1622 for definining proof methods in ML;
  1623 
  1624 * Isar/Provers: intro/elim/dest attributes changed; renamed
  1625 intro/intro!/intro!! flags to intro!/intro/intro? (INCOMPATIBILITY, in
  1626 most cases, one should have to change intro!! to intro? only);
  1627 replaced "delrule" by "rule del";
  1628 
  1629 * Isar/Provers: new 'hypsubst' method, plain 'subst' method and
  1630 'symmetric' attribute (the latter supercedes [RS sym]);
  1631 
  1632 * Isar/Provers: splitter support (via 'split' attribute and 'simp'
  1633 method modifier); 'simp' method: 'only:' modifier removes loopers as
  1634 well (including splits);
  1635 
  1636 * Isar/Provers: Simplifier and Classical methods now support all kind
  1637 of modifiers used in the past, including 'cong', 'iff', etc.
  1638 
  1639 * Isar/Provers: added 'fastsimp' and 'clarsimp' methods (combination
  1640 of Simplifier and Classical reasoner);
  1641 
  1642 * Isar/HOL: new proof method 'cases' and improved version of 'induct'
  1643 now support named cases; major packages (inductive, datatype, primrec,
  1644 recdef) support case names and properly name parameters;
  1645 
  1646 * Isar/HOL: new transitivity rules for substitution in inequalities --
  1647 monotonicity conditions are extracted to be proven at end of
  1648 calculations;
  1649 
  1650 * Isar/HOL: removed 'case_split' thm binding, should use 'cases' proof
  1651 method anyway;
  1652 
  1653 * Isar/HOL: removed old expand_if = split_if; theorems if_splits =
  1654 split_if split_if_asm; datatype package provides theorems foo.splits =
  1655 foo.split foo.split_asm for each datatype;
  1656 
  1657 * Isar/HOL: tuned inductive package, rename "intrs" to "intros"
  1658 (potential INCOMPATIBILITY), emulation of mk_cases feature for proof
  1659 scripts: new 'inductive_cases' command and 'ind_cases' method; (Note:
  1660 use "(cases (simplified))" method in proper proof texts);
  1661 
  1662 * Isar/HOL: added global 'arith_split' attribute for 'arith' method;
  1663 
  1664 * Isar: names of theorems etc. may be natural numbers as well;
  1665 
  1666 * Isar: 'pr' command: optional arguments for goals_limit and
  1667 ProofContext.prems_limit; no longer prints theory contexts, but only
  1668 proof states;
  1669 
  1670 * Isar: diagnostic commands 'pr', 'thm', 'prop', 'term', 'typ' admit
  1671 additional print modes to be specified; e.g. "pr(latex)" will print
  1672 proof state according to the Isabelle LaTeX style;
  1673 
  1674 * Isar: improved support for emulating tactic scripts, including proof
  1675 methods 'rule_tac' etc., 'cut_tac', 'thin_tac', 'subgoal_tac',
  1676 'rename_tac', 'rotate_tac', 'tactic', and 'case_tac' / 'induct_tac'
  1677 (for HOL datatypes);
  1678 
  1679 * Isar: simplified (more robust) goal selection of proof methods: 1st
  1680 goal, all goals, or explicit goal specifier (tactic emulation); thus
  1681 'proof method scripts' have to be in depth-first order;
  1682 
  1683 * Isar: tuned 'let' syntax: replaced 'as' keyword by 'and';
  1684 
  1685 * Isar: removed 'help' command, which hasn't been too helpful anyway;
  1686 should instead use individual commands for printing items
  1687 (print_commands, print_methods etc.);
  1688 
  1689 * Isar: added 'nothing' --- the empty list of theorems;
  1690 
  1691 
  1692 *** HOL ***
  1693 
  1694 * HOL/MicroJava: formalization of a fragment of Java, together with a
  1695 corresponding virtual machine and a specification of its bytecode
  1696 verifier and a lightweight bytecode verifier, including proofs of
  1697 type-safety; by Gerwin Klein, Tobias Nipkow, David von Oheimb, and
  1698 Cornelia Pusch (see also the homepage of project Bali at
  1699 http://isabelle.in.tum.de/Bali/);
  1700 
  1701 * HOL/Algebra: new theory of rings and univariate polynomials, by
  1702 Clemens Ballarin;
  1703 
  1704 * HOL/NumberTheory: fundamental Theorem of Arithmetic, Chinese
  1705 Remainder Theorem, Fermat/Euler Theorem, Wilson's Theorem, by Thomas M
  1706 Rasmussen;
  1707 
  1708 * HOL/Lattice: fundamental concepts of lattice theory and order
  1709 structures, including duals, properties of bounds versus algebraic
  1710 laws, lattice operations versus set-theoretic ones, the Knaster-Tarski
  1711 Theorem for complete lattices etc.; may also serve as a demonstration
  1712 for abstract algebraic reasoning using axiomatic type classes, and
  1713 mathematics-style proof in Isabelle/Isar; by Markus Wenzel;
  1714 
  1715 * HOL/Prolog: a (bare-bones) implementation of Lambda-Prolog, by David
  1716 von Oheimb;
  1717 
  1718 * HOL/IMPP: extension of IMP with local variables and mutually
  1719 recursive procedures, by David von Oheimb;
  1720 
  1721 * HOL/Lambda: converted into new-style theory and document;
  1722 
  1723 * HOL/ex/Multiquote: example of multiple nested quotations and
  1724 anti-quotations -- basically a generalized version of de-Bruijn
  1725 representation; very useful in avoiding lifting of operations;
  1726 
  1727 * HOL/record: added general record equality rule to simpset; fixed
  1728 select-update simplification procedure to handle extended records as
  1729 well; admit "r" as field name;
  1730 
  1731 * HOL: 0 is now overloaded over the new sort "zero", allowing its use with
  1732 other numeric types and also as the identity of groups, rings, etc.;
  1733 
  1734 * HOL: new axclass plus_ac0 for addition with the AC-laws and 0 as identity.
  1735 Types nat and int belong to this axclass;
  1736 
  1737 * HOL: greatly improved simplification involving numerals of type nat, int, real:
  1738    (i + #8 + j) = Suc k simplifies to  #7 + (i + j) = k
  1739    i*j + k + j*#3*i     simplifies to  #4*(i*j) + k
  1740   two terms #m*u and #n*u are replaced by #(m+n)*u
  1741     (where #m, #n and u can implicitly be 1; this is simproc combine_numerals)
  1742   and the term/formula #m*u+x ~~ #n*u+y simplifies simplifies to #(m-n)+x ~~ y
  1743     or x ~~ #(n-m)+y, where ~~ is one of = < <= or - (simproc cancel_numerals);
  1744 
  1745 * HOL: meson_tac is available (previously in ex/meson.ML); it is a
  1746 powerful prover for predicate logic but knows nothing of clasets; see
  1747 ex/mesontest.ML and ex/mesontest2.ML for example applications;
  1748 
  1749 * HOL: new version of "case_tac" subsumes both boolean case split and
  1750 "exhaust_tac" on datatypes; INCOMPATIBILITY: exhaust_tac no longer
  1751 exists, may define val exhaust_tac = case_tac for ad-hoc portability;
  1752 
  1753 * HOL: simplification no longer dives into case-expressions: only the
  1754 selector expression is simplified, but not the remaining arms; to
  1755 enable full simplification of case-expressions for datatype t, you may
  1756 remove t.weak_case_cong from the simpset, either globally (Delcongs
  1757 [thm"t.weak_case_cong"];) or locally (delcongs [...]).
  1758 
  1759 * HOL/recdef: the recursion equations generated by 'recdef' for
  1760 function 'f' are now called f.simps instead of f.rules; if all
  1761 termination conditions are proved automatically, these simplification
  1762 rules are added to the simpset, as in primrec; rules may be named
  1763 individually as well, resulting in a separate list of theorems for
  1764 each equation;
  1765 
  1766 * HOL/While is a new theory that provides a while-combinator. It
  1767 permits the definition of tail-recursive functions without the
  1768 provision of a termination measure. The latter is necessary once the
  1769 invariant proof rule for while is applied.
  1770 
  1771 * HOL: new (overloaded) notation for the set of elements below/above
  1772 some element: {..u}, {..u(}, {l..}, {)l..}. See theory SetInterval.
  1773 
  1774 * HOL: theorems impI, allI, ballI bound as "strip";
  1775 
  1776 * HOL: new tactic induct_thm_tac: thm -> string -> int -> tactic
  1777 induct_tac th "x1 ... xn" expects th to have a conclusion of the form
  1778 P v1 ... vn and abbreviates res_inst_tac [("v1","x1"),...,("vn","xn")] th;
  1779 
  1780 * HOL/Real: "rabs" replaced by overloaded "abs" function;
  1781 
  1782 * HOL: theory Sexp now in HOL/Induct examples (it used to be part of
  1783 main HOL, but was unused);
  1784 
  1785 * HOL: fewer consts declared as global (e.g. have to refer to
  1786 "Lfp.lfp" instead of "lfp" internally; affects ML packages only);
  1787 
  1788 * HOL: tuned AST representation of nested pairs, avoiding bogus output
  1789 in case of overlap with user translations (e.g. judgements over
  1790 tuples); (note that the underlying logical represenation is still
  1791 bogus);
  1792 
  1793 
  1794 *** ZF ***
  1795 
  1796 * ZF: simplification automatically cancels common terms in arithmetic
  1797 expressions over nat and int;
  1798 
  1799 * ZF: new treatment of nat to minimize type-checking: all operators
  1800 coerce their operands to a natural number using the function natify,
  1801 making the algebraic laws unconditional;
  1802 
  1803 * ZF: as above, for int: operators coerce their operands to an integer
  1804 using the function intify;
  1805 
  1806 * ZF: the integer library now contains many of the usual laws for the
  1807 orderings, including $<=, and monotonicity laws for $+ and $*;
  1808 
  1809 * ZF: new example ZF/ex/NatSum to demonstrate integer arithmetic
  1810 simplification;
  1811 
  1812 * FOL and ZF: AddIffs now available, giving theorems of the form P<->Q
  1813 to the simplifier and classical reasoner simultaneously;
  1814 
  1815 
  1816 *** General ***
  1817 
  1818 * Provers: blast_tac now handles actual object-logic rules as
  1819 assumptions; note that auto_tac uses blast_tac internally as well;
  1820 
  1821 * Provers: new functions rulify/rulify_no_asm: thm -> thm for turning
  1822 outer -->/All/Ball into ==>/!!; qed_spec_mp now uses rulify_no_asm;
  1823 
  1824 * Provers: delrules now handles destruct rules as well (no longer need
  1825 explicit make_elim);
  1826 
  1827 * Provers: Blast_tac now warns of and ignores "weak elimination rules" e.g.
  1828   [| inj ?f;          ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1829 use instead the strong form,
  1830   [| inj ?f; ~ ?W ==> ?f ?x = ?f ?y; ?x = ?y ==> ?W |] ==> ?W
  1831 in HOL, FOL and ZF the function cla_make_elim will create such rules
  1832 from destruct-rules;
  1833 
  1834 * Provers: Simplifier.easy_setup provides a fast path to basic
  1835 Simplifier setup for new object-logics;
  1836 
  1837 * Pure: AST translation rules no longer require constant head on LHS;
  1838 
  1839 * Pure: improved name spaces: ambiguous output is qualified; support
  1840 for hiding of names;
  1841 
  1842 * system: smart setup of canonical ML_HOME, ISABELLE_INTERFACE, and
  1843 XSYMBOL_HOME; no longer need to do manual configuration in most
  1844 situations;
  1845 
  1846 * system: compression of ML heaps images may now be controlled via -c
  1847 option of isabelle and isatool usedir (currently only observed by
  1848 Poly/ML);
  1849 
  1850 * system: isatool installfonts may handle X-Symbol fonts as well (very
  1851 useful for remote X11);
  1852 
  1853 * system: provide TAGS file for Isabelle sources;
  1854 
  1855 * ML: infix 'OF' is a version of 'MRS' with more appropriate argument
  1856 order;
  1857 
  1858 * ML: renamed flags Syntax.trace_norm_ast to Syntax.trace_ast; global
  1859 timing flag supersedes proof_timing and Toplevel.trace;
  1860 
  1861 * ML: new combinators |>> and |>>> for incremental transformations
  1862 with secondary results (e.g. certain theory extensions):
  1863 
  1864 * ML: PureThy.add_defs gets additional argument to indicate potential
  1865 overloading (usually false);
  1866 
  1867 * ML: PureThy.add_thms/add_axioms/add_defs now return theorems as
  1868 results;
  1869 
  1870 
  1871 
  1872 New in Isabelle99 (October 1999)
  1873 --------------------------------
  1874 
  1875 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  1876 
  1877 * HOL: The THEN and ELSE parts of conditional expressions (if P then x else y)
  1878 are no longer simplified.  (This allows the simplifier to unfold recursive
  1879 functional programs.)  To restore the old behaviour, declare
  1880 
  1881     Delcongs [if_weak_cong];
  1882 
  1883 * HOL: Removed the obsolete syntax "Compl A"; use -A for set
  1884 complement;
  1885 
  1886 * HOL: the predicate "inj" is now defined by translation to "inj_on";
  1887 
  1888 * HOL/datatype: mutual_induct_tac no longer exists --
  1889   use induct_tac "x_1 ... x_n" instead of mutual_induct_tac ["x_1", ..., "x_n"]
  1890 
  1891 * HOL/typedef: fixed type inference for representing set; type
  1892 arguments now have to occur explicitly on the rhs as type constraints;
  1893 
  1894 * ZF: The con_defs part of an inductive definition may no longer refer
  1895 to constants declared in the same theory;
  1896 
  1897 * HOL, ZF: the function mk_cases, generated by the inductive
  1898 definition package, has lost an argument.  To simplify its result, it
  1899 uses the default simpset instead of a supplied list of theorems.
  1900 
  1901 * HOL/List: the constructors of type list are now Nil and Cons;
  1902 
  1903 * Simplifier: the type of the infix ML functions
  1904         setSSolver addSSolver setSolver addSolver
  1905 is now  simpset * solver -> simpset  where `solver' is a new abstract type
  1906 for packaging solvers. A solver is created via
  1907         mk_solver: string -> (thm list -> int -> tactic) -> solver
  1908 where the string argument is only a comment.
  1909 
  1910 
  1911 *** Proof tools ***
  1912 
  1913 * Provers/Arith/fast_lin_arith.ML contains a functor for creating a
  1914 decision procedure for linear arithmetic. Currently it is used for
  1915 types `nat', `int', and `real' in HOL (see below); it can, should and
  1916 will be instantiated for other types and logics as well.
  1917 
  1918 * The simplifier now accepts rewrite rules with flexible heads, eg
  1919      hom ?f ==> ?f(?x+?y) = ?f ?x + ?f ?y
  1920   They are applied like any rule with a non-pattern lhs, i.e. by first-order
  1921   matching.
  1922 
  1923 
  1924 *** General ***
  1925 
  1926 * New Isabelle/Isar subsystem provides an alternative to traditional
  1927 tactical theorem proving; together with the ProofGeneral/isar user
  1928 interface it offers an interactive environment for developing human
  1929 readable proof documents (Isar == Intelligible semi-automated
  1930 reasoning); for further information see isatool doc isar-ref,
  1931 src/HOL/Isar_examples and http://isabelle.in.tum.de/Isar/
  1932 
  1933 * improved and simplified presentation of theories: better HTML markup
  1934 (including colors), graph views in several sizes; isatool usedir now
  1935 provides a proper interface for user theories (via -P option); actual
  1936 document preparation based on (PDF)LaTeX is available as well (for
  1937 new-style theories only); see isatool doc system for more information;
  1938 
  1939 * native support for Proof General, both for classic Isabelle and
  1940 Isabelle/Isar;
  1941 
  1942 * ML function thm_deps visualizes dependencies of theorems and lemmas,
  1943 using the graph browser tool;
  1944 
  1945 * Isabelle manuals now also available as PDF;
  1946 
  1947 * theory loader rewritten from scratch (may not be fully
  1948 bug-compatible); old loadpath variable has been replaced by show_path,
  1949 add_path, del_path, reset_path functions; new operations such as
  1950 update_thy, touch_thy, remove_thy, use/update_thy_only (see also
  1951 isatool doc ref);
  1952 
  1953 * improved isatool install: option -k creates KDE application icon,
  1954 option -p DIR installs standalone binaries;
  1955 
  1956 * added ML_PLATFORM setting (useful for cross-platform installations);
  1957 more robust handling of platform specific ML images for SML/NJ;
  1958 
  1959 * the settings environment is now statically scoped, i.e. it is never
  1960 created again in sub-processes invoked from isabelle, isatool, or
  1961 Isabelle;
  1962 
  1963 * path element specification '~~' refers to '$ISABELLE_HOME';
  1964 
  1965 * in locales, the "assumes" and "defines" parts may be omitted if
  1966 empty;
  1967 
  1968 * new print_mode "xsymbols" for extended symbol support (e.g. genuine
  1969 long arrows);
  1970 
  1971 * new print_mode "HTML";
  1972 
  1973 * new flag show_tags controls display of tags of theorems (which are
  1974 basically just comments that may be attached by some tools);
  1975 
  1976 * Isamode 2.6 requires patch to accomodate change of Isabelle font
  1977 mode and goal output format:
  1978 
  1979 diff -r Isamode-2.6/elisp/isa-load.el Isamode/elisp/isa-load.el
  1980 244c244
  1981 <       (list (isa-getenv "ISABELLE") "-msymbols" logic-name)
  1982 ---
  1983 >       (list (isa-getenv "ISABELLE") "-misabelle_font" "-msymbols" logic-name)
  1984 diff -r Isabelle-2.6/elisp/isa-proofstate.el Isamode/elisp/isa-proofstate.el
  1985 181c181
  1986 < (defconst proofstate-proofstart-regexp "^Level [0-9]+$"
  1987 ---
  1988 > (defconst proofstate-proofstart-regexp "^Level [0-9]+"
  1989 
  1990 * function bind_thms stores lists of theorems (cf. bind_thm);
  1991 
  1992 * new shorthand tactics ftac, eatac, datac, fatac;
  1993 
  1994 * qed (and friends) now accept "" as result name; in that case the
  1995 theorem is not stored, but proper checks and presentation of the
  1996 result still apply;
  1997 
  1998 * theorem database now also indexes constants "Trueprop", "all",
  1999 "==>", "=="; thus thms_containing, findI etc. may retrieve more rules;
  2000 
  2001 
  2002 *** HOL ***
  2003 
  2004 ** HOL arithmetic **
  2005 
  2006 * There are now decision procedures for linear arithmetic over nat and
  2007 int:
  2008 
  2009 1. arith_tac copes with arbitrary formulae involving `=', `<', `<=',
  2010 `+', `-', `Suc', `min', `max' and numerical constants; other subterms
  2011 are treated as atomic; subformulae not involving type `nat' or `int'
  2012 are ignored; quantified subformulae are ignored unless they are
  2013 positive universal or negative existential. The tactic has to be
  2014 invoked by hand and can be a little bit slow. In particular, the
  2015 running time is exponential in the number of occurrences of `min' and
  2016 `max', and `-' on `nat'.
  2017 
  2018 2. fast_arith_tac is a cut-down version of arith_tac: it only takes
  2019 (negated) (in)equalities among the premises and the conclusion into
  2020 account (i.e. no compound formulae) and does not know about `min' and
  2021 `max', and `-' on `nat'. It is fast and is used automatically by the
  2022 simplifier.
  2023 
  2024 NB: At the moment, these decision procedures do not cope with mixed
  2025 nat/int formulae where the two parts interact, such as `m < n ==>
  2026 int(m) < int(n)'.
  2027 
  2028 * HOL/Numeral provides a generic theory of numerals (encoded
  2029 efficiently as bit strings); setup for types nat/int/real is in place;
  2030 INCOMPATIBILITY: since numeral syntax is now polymorphic, rather than
  2031 int, existing theories and proof scripts may require a few additional
  2032 type constraints;
  2033 
  2034 * integer division and remainder can now be performed on constant
  2035 arguments;
  2036 
  2037 * many properties of integer multiplication, division and remainder
  2038 are now available;
  2039 
  2040 * An interface to the Stanford Validity Checker (SVC) is available through the
  2041 tactic svc_tac.  Propositional tautologies and theorems of linear arithmetic
  2042 are proved automatically.  SVC must be installed separately, and its results
  2043 must be TAKEN ON TRUST (Isabelle does not check the proofs, but tags any
  2044 invocation of the underlying oracle).  For SVC see
  2045   http://verify.stanford.edu/SVC
  2046 
  2047 * IsaMakefile: the HOL-Real target now builds an actual image;
  2048 
  2049 
  2050 ** HOL misc **
  2051 
  2052 * HOL/Real/HahnBanach: the Hahn-Banach theorem for real vector spaces
  2053 (in Isabelle/Isar) -- by Gertrud Bauer;
  2054 
  2055 * HOL/BCV: generic model of bytecode verification, i.e. data-flow
  2056 analysis for assembly languages with subtypes;
  2057 
  2058 * HOL/TLA (Lamport's Temporal Logic of Actions): major reorganization
  2059 -- avoids syntactic ambiguities and treats state, transition, and
  2060 temporal levels more uniformly; introduces INCOMPATIBILITIES due to
  2061 changed syntax and (many) tactics;
  2062 
  2063 * HOL/inductive: Now also handles more general introduction rules such
  2064   as "ALL y. (y, x) : r --> y : acc r ==> x : acc r"; monotonicity
  2065   theorems are now maintained within the theory (maintained via the
  2066   "mono" attribute);
  2067 
  2068 * HOL/datatype: Now also handles arbitrarily branching datatypes
  2069   (using function types) such as
  2070 
  2071   datatype 'a tree = Atom 'a | Branch "nat => 'a tree"
  2072 
  2073 * HOL/record: record_simproc (part of the default simpset) takes care
  2074 of selectors applied to updated records; record_split_tac is no longer
  2075 part of the default claset; update_defs may now be removed from the
  2076 simpset in many cases; COMPATIBILITY: old behavior achieved by
  2077 
  2078   claset_ref () := claset() addSWrapper record_split_wrapper;
  2079   Delsimprocs [record_simproc]
  2080 
  2081 * HOL/typedef: fixed type inference for representing set; type
  2082 arguments now have to occur explicitly on the rhs as type constraints;
  2083 
  2084 * HOL/recdef (TFL): 'congs' syntax now expects comma separated list of theorem
  2085 names rather than an ML expression;
  2086 
  2087 * HOL/defer_recdef (TFL): like recdef but the well-founded relation can be
  2088 supplied later.  Program schemes can be defined, such as
  2089     "While B C s = (if B s then While B C (C s) else s)"
  2090 where the well-founded relation can be chosen after B and C have been given.
  2091 
  2092 * HOL/List: the constructors of type list are now Nil and Cons;
  2093 INCOMPATIBILITY: while [] and infix # syntax is still there, of
  2094 course, ML tools referring to List.list.op # etc. have to be adapted;
  2095 
  2096 * HOL_quantifiers flag superseded by "HOL" print mode, which is
  2097 disabled by default; run isabelle with option -m HOL to get back to
  2098 the original Gordon/HOL-style output;
  2099 
  2100 * HOL/Ord.thy: new bounded quantifier syntax (input only): ALL x<y. P,
  2101 ALL x<=y. P, EX x<y. P, EX x<=y. P;
  2102 
  2103 * HOL basic syntax simplified (more orthogonal): all variants of
  2104 All/Ex now support plain / symbolic / HOL notation; plain syntax for
  2105 Eps operator is provided as well: "SOME x. P[x]";
  2106 
  2107 * HOL/Sum.thy: sum_case has been moved to HOL/Datatype;
  2108 
  2109 * HOL/Univ.thy: infix syntax <*>, <+>, <**>, <+> eliminated and made
  2110 thus available for user theories;
  2111 
  2112 * HOLCF/IOA/Sequents: renamed 'Cons' to 'Consq' to avoid clash with
  2113 HOL/List; hardly an INCOMPATIBILITY since '>>' syntax is used all the
  2114 time;
  2115 
  2116 * HOL: new tactic smp_tac: int -> int -> tactic, which applies spec
  2117 several times and then mp;
  2118 
  2119 
  2120 *** LK ***
  2121 
  2122 * the notation <<...>> is now available as a notation for sequences of
  2123 formulas;
  2124 
  2125 * the simplifier is now installed
  2126 
  2127 * the axiom system has been generalized (thanks to Soren Heilmann)
  2128 
  2129 * the classical reasoner now has a default rule database
  2130 
  2131 
  2132 *** ZF ***
  2133 
  2134 * new primrec section allows primitive recursive functions to be given
  2135 directly (as in HOL) over datatypes and the natural numbers;
  2136 
  2137 * new tactics induct_tac and exhaust_tac for induction (or case
  2138 analysis) over datatypes and the natural numbers;
  2139 
  2140 * the datatype declaration of type T now defines the recursor T_rec;
  2141 
  2142 * simplification automatically does freeness reasoning for datatype
  2143 constructors;
  2144 
  2145 * automatic type-inference, with AddTCs command to insert new
  2146 type-checking rules;
  2147 
  2148 * datatype introduction rules are now added as Safe Introduction rules
  2149 to the claset;
  2150 
  2151 * the syntax "if P then x else y" is now available in addition to
  2152 if(P,x,y);
  2153 
  2154 
  2155 *** Internal programming interfaces ***
  2156 
  2157 * tuned simplifier trace output; new flag debug_simp;
  2158 
  2159 * structures Vartab / Termtab (instances of TableFun) offer efficient
  2160 tables indexed by indexname_ord / term_ord (compatible with aconv);
  2161 
  2162 * AxClass.axclass_tac lost the theory argument;
  2163 
  2164 * tuned current_goals_markers semantics: begin / end goal avoids
  2165 printing empty lines;
  2166 
  2167 * removed prs and prs_fn hook, which was broken because it did not
  2168 include \n in its semantics, forcing writeln to add one
  2169 uncoditionally; replaced prs_fn by writeln_fn; consider std_output:
  2170 string -> unit if you really want to output text without newline;
  2171 
  2172 * Symbol.output subject to print mode; INCOMPATIBILITY: defaults to
  2173 plain output, interface builders may have to enable 'isabelle_font'
  2174 mode to get Isabelle font glyphs as before;
  2175 
  2176 * refined token_translation interface; INCOMPATIBILITY: output length
  2177 now of type real instead of int;
  2178 
  2179 * theory loader actions may be traced via new ThyInfo.add_hook
  2180 interface (see src/Pure/Thy/thy_info.ML); example application: keep
  2181 your own database of information attached to *whole* theories -- as
  2182 opposed to intra-theory data slots offered via TheoryDataFun;
  2183 
  2184 * proper handling of dangling sort hypotheses (at last!);
  2185 Thm.strip_shyps and Drule.strip_shyps_warning take care of removing
  2186 extra sort hypotheses that can be witnessed from the type signature;
  2187 the force_strip_shyps flag is gone, any remaining shyps are simply
  2188 left in the theorem (with a warning issued by strip_shyps_warning);
  2189 
  2190 
  2191 
  2192 New in Isabelle98-1 (October 1998)
  2193 ----------------------------------
  2194 
  2195 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2196 
  2197 * several changes of automated proof tools;
  2198 
  2199 * HOL: major changes to the inductive and datatype packages, including
  2200 some minor incompatibilities of theory syntax;
  2201 
  2202 * HOL: renamed r^-1 to 'converse' from 'inverse'; 'inj_onto' is now
  2203 called `inj_on';
  2204 
  2205 * HOL: removed duplicate thms in Arith:
  2206   less_imp_add_less  should be replaced by  trans_less_add1
  2207   le_imp_add_le      should be replaced by  trans_le_add1
  2208 
  2209 * HOL: unary minus is now overloaded (new type constraints may be
  2210 required);
  2211 
  2212 * HOL and ZF: unary minus for integers is now #- instead of #~.  In
  2213 ZF, expressions such as n#-1 must be changed to n#- 1, since #-1 is
  2214 now taken as an integer constant.
  2215 
  2216 * Pure: ML function 'theory_of' renamed to 'theory';
  2217 
  2218 
  2219 *** Proof tools ***
  2220 
  2221 * Simplifier:
  2222   1. Asm_full_simp_tac is now more aggressive.
  2223      1. It will sometimes reorient premises if that increases their power to
  2224         simplify.
  2225      2. It does no longer proceed strictly from left to right but may also
  2226         rotate premises to achieve further simplification.
  2227      For compatibility reasons there is now Asm_lr_simp_tac which is like the
  2228      old Asm_full_simp_tac in that it does not rotate premises.
  2229   2. The simplifier now knows a little bit about nat-arithmetic.
  2230 
  2231 * Classical reasoner: wrapper mechanism for the classical reasoner now
  2232 allows for selected deletion of wrappers, by introduction of names for
  2233 wrapper functionals.  This implies that addbefore, addSbefore,
  2234 addaltern, and addSaltern now take a pair (name, tactic) as argument,
  2235 and that adding two tactics with the same name overwrites the first
  2236 one (emitting a warning).
  2237   type wrapper = (int -> tactic) -> (int -> tactic)
  2238   setWrapper, setSWrapper, compWrapper and compSWrapper are replaced by
  2239   addWrapper, addSWrapper: claset * (string * wrapper) -> claset
  2240   delWrapper, delSWrapper: claset *  string            -> claset
  2241   getWrapper is renamed to appWrappers, getSWrapper to appSWrappers;
  2242 
  2243 * Classical reasoner: addbefore/addSbefore now have APPEND/ORELSE
  2244 semantics; addbefore now affects only the unsafe part of step_tac
  2245 etc.; this affects addss/auto_tac/force_tac, so EXISTING PROOFS MAY
  2246 FAIL, but proofs should be fixable easily, e.g. by replacing Auto_tac
  2247 by Force_tac;
  2248 
  2249 * Classical reasoner: setwrapper to setWrapper and compwrapper to
  2250 compWrapper; added safe wrapper (and access functions for it);
  2251 
  2252 * HOL/split_all_tac is now much faster and fails if there is nothing
  2253 to split.  Some EXISTING PROOFS MAY REQUIRE ADAPTION because the order
  2254 and the names of the automatically generated variables have changed.
  2255 split_all_tac has moved within claset() from unsafe wrappers to safe
  2256 wrappers, which means that !!-bound variables are split much more
  2257 aggressively, and safe_tac and clarify_tac now split such variables.
  2258 If this splitting is not appropriate, use delSWrapper "split_all_tac".
  2259 Note: the same holds for record_split_tac, which does the job of
  2260 split_all_tac for record fields.
  2261 
  2262 * HOL/Simplifier: Rewrite rules for case distinctions can now be added
  2263 permanently to the default simpset using Addsplits just like
  2264 Addsimps. They can be removed via Delsplits just like
  2265 Delsimps. Lower-case versions are also available.
  2266 
  2267 * HOL/Simplifier: The rule split_if is now part of the default
  2268 simpset. This means that the simplifier will eliminate all occurrences
  2269 of if-then-else in the conclusion of a goal. To prevent this, you can
  2270 either remove split_if completely from the default simpset by
  2271 `Delsplits [split_if]' or remove it in a specific call of the
  2272 simplifier using `... delsplits [split_if]'.  You can also add/delete
  2273 other case splitting rules to/from the default simpset: every datatype
  2274 generates suitable rules `split_t_case' and `split_t_case_asm' (where
  2275 t is the name of the datatype).
  2276 
  2277 * Classical reasoner / Simplifier combination: new force_tac (and
  2278 derivatives Force_tac, force) combines rewriting and classical
  2279 reasoning (and whatever other tools) similarly to auto_tac, but is
  2280 aimed to solve the given subgoal completely.
  2281 
  2282 
  2283 *** General ***
  2284 
  2285 * new top-level commands `Goal' and `Goalw' that improve upon `goal'
  2286 and `goalw': the theory is no longer needed as an explicit argument -
  2287 the current theory context is used; assumptions are no longer returned
  2288 at the ML-level unless one of them starts with ==> or !!; it is
  2289 recommended to convert to these new commands using isatool fixgoal
  2290 (backup your sources first!);
  2291 
  2292 * new top-level commands 'thm' and 'thms' for retrieving theorems from
  2293 the current theory context, and 'theory' to lookup stored theories;
  2294 
  2295 * new theory section 'locale' for declaring constants, assumptions and
  2296 definitions that have local scope;
  2297 
  2298 * new theory section 'nonterminals' for purely syntactic types;
  2299 
  2300 * new theory section 'setup' for generic ML setup functions
  2301 (e.g. package initialization);
  2302 
  2303 * the distribution now includes Isabelle icons: see
  2304 lib/logo/isabelle-{small,tiny}.xpm;
  2305 
  2306 * isatool install - install binaries with absolute references to
  2307 ISABELLE_HOME/bin;
  2308 
  2309 * isatool logo -- create instances of the Isabelle logo (as EPS);
  2310 
  2311 * print mode 'emacs' reserved for Isamode;
  2312 
  2313 * support multiple print (ast) translations per constant name;
  2314 
  2315 * theorems involving oracles are now printed with a suffixed [!];
  2316 
  2317 
  2318 *** HOL ***
  2319 
  2320 * there is now a tutorial on Isabelle/HOL (do 'isatool doc tutorial');
  2321 
  2322 * HOL/inductive package reorganized and improved: now supports mutual
  2323 definitions such as
  2324 
  2325   inductive EVEN ODD
  2326     intrs
  2327       null "0 : EVEN"
  2328       oddI "n : EVEN ==> Suc n : ODD"
  2329       evenI "n : ODD ==> Suc n : EVEN"
  2330 
  2331 new theorem list "elims" contains an elimination rule for each of the
  2332 recursive sets; inductive definitions now handle disjunctive premises
  2333 correctly (also ZF);
  2334 
  2335 INCOMPATIBILITIES: requires Inductive as an ancestor; component
  2336 "mutual_induct" no longer exists - the induction rule is always
  2337 contained in "induct";
  2338 
  2339 
  2340 * HOL/datatype package re-implemented and greatly improved: now
  2341 supports mutually recursive datatypes such as
  2342 
  2343   datatype
  2344     'a aexp = IF_THEN_ELSE ('a bexp) ('a aexp) ('a aexp)
  2345             | SUM ('a aexp) ('a aexp)
  2346             | DIFF ('a aexp) ('a aexp)
  2347             | NUM 'a
  2348   and
  2349     'a bexp = LESS ('a aexp) ('a aexp)
  2350             | AND ('a bexp) ('a bexp)
  2351             | OR ('a bexp) ('a bexp)
  2352 
  2353 as well as indirectly recursive datatypes such as
  2354 
  2355   datatype
  2356     ('a, 'b) term = Var 'a
  2357                   | App 'b ((('a, 'b) term) list)
  2358 
  2359 The new tactic  mutual_induct_tac [<var_1>, ..., <var_n>] i  performs
  2360 induction on mutually / indirectly recursive datatypes.
  2361 
  2362 Primrec equations are now stored in theory and can be accessed via
  2363 <function_name>.simps.
  2364 
  2365 INCOMPATIBILITIES:
  2366 
  2367   - Theories using datatypes must now have theory Datatype as an
  2368     ancestor.
  2369   - The specific <typename>.induct_tac no longer exists - use the
  2370     generic induct_tac instead.
  2371   - natE has been renamed to nat.exhaust - use exhaust_tac
  2372     instead of res_inst_tac ... natE. Note that the variable
  2373     names in nat.exhaust differ from the names in natE, this
  2374     may cause some "fragile" proofs to fail.
  2375   - The theorems split_<typename>_case and split_<typename>_case_asm
  2376     have been renamed to <typename>.split and <typename>.split_asm.
  2377   - Since default sorts of type variables are now handled correctly,
  2378     some datatype definitions may have to be annotated with explicit
  2379     sort constraints.
  2380   - Primrec definitions no longer require function name and type
  2381     of recursive argument.
  2382 
  2383 Consider using isatool fixdatatype to adapt your theories and proof
  2384 scripts to the new package (backup your sources first!).
  2385 
  2386 
  2387 * HOL/record package: considerably improved implementation; now
  2388 includes concrete syntax for record types, terms, updates; theorems
  2389 for surjective pairing and splitting !!-bound record variables; proof
  2390 support is as follows:
  2391 
  2392   1) standard conversions (selectors or updates applied to record
  2393 constructor terms) are part of the standard simpset;
  2394 
  2395   2) inject equations of the form ((x, y) = (x', y')) == x=x' & y=y' are
  2396 made part of standard simpset and claset via addIffs;
  2397 
  2398   3) a tactic for record field splitting (record_split_tac) is part of
  2399 the standard claset (addSWrapper);
  2400 
  2401 To get a better idea about these rules you may retrieve them via
  2402 something like 'thms "foo.simps"' or 'thms "foo.iffs"', where "foo" is
  2403 the name of your record type.
  2404 
  2405 The split tactic 3) conceptually simplifies by the following rule:
  2406 
  2407   "(!!x. PROP ?P x) == (!!a b. PROP ?P (a, b))"
  2408 
  2409 Thus any record variable that is bound by meta-all will automatically
  2410 blow up into some record constructor term, consequently the
  2411 simplifications of 1), 2) apply.  Thus force_tac, auto_tac etc. shall
  2412 solve record problems automatically.
  2413 
  2414 
  2415 * reorganized the main HOL image: HOL/Integ and String loaded by
  2416 default; theory Main includes everything;
  2417 
  2418 * automatic simplification of integer sums and comparisons, using cancellation;
  2419 
  2420 * added option_map_eq_Some and not_Some_eq to the default simpset and claset;
  2421 
  2422 * added disj_not1 = "(~P | Q) = (P --> Q)" to the default simpset;
  2423 
  2424 * many new identities for unions, intersections, set difference, etc.;
  2425 
  2426 * expand_if, expand_split, expand_sum_case and expand_nat_case are now
  2427 called split_if, split_split, split_sum_case and split_nat_case (to go
  2428 with add/delsplits);
  2429 
  2430 * HOL/Prod introduces simplification procedure unit_eq_proc rewriting
  2431 (?x::unit) = (); this is made part of the default simpset, which COULD
  2432 MAKE EXISTING PROOFS FAIL under rare circumstances (consider
  2433 'Delsimprocs [unit_eq_proc];' as last resort); also note that
  2434 unit_abs_eta_conv is added in order to counter the effect of
  2435 unit_eq_proc on (%u::unit. f u), replacing it by f rather than by
  2436 %u.f();
  2437 
  2438 * HOL/Fun INCOMPATIBILITY: `inj_onto' is now called `inj_on' (which
  2439 makes more sense);
  2440 
  2441 * HOL/Set INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2442   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2443   disjointness reasoning but breaking a few old proofs.
  2444 
  2445 * HOL/Relation INCOMPATIBILITY: renamed the relational operator r^-1
  2446 to 'converse' from 'inverse' (for compatibility with ZF and some
  2447 literature);
  2448 
  2449 * HOL/recdef can now declare non-recursive functions, with {} supplied as
  2450 the well-founded relation;
  2451 
  2452 * HOL/Set INCOMPATIBILITY: the complement of set A is now written -A instead of
  2453     Compl A.  The "Compl" syntax remains available as input syntax for this
  2454     release ONLY.
  2455 
  2456 * HOL/Update: new theory of function updates:
  2457     f(a:=b) == %x. if x=a then b else f x
  2458 may also be iterated as in f(a:=b,c:=d,...);
  2459 
  2460 * HOL/Vimage: new theory for inverse image of a function, syntax f-``B;
  2461 
  2462 * HOL/List:
  2463   - new function list_update written xs[i:=v] that updates the i-th
  2464     list position. May also be iterated as in xs[i:=a,j:=b,...].
  2465   - new function `upt' written [i..j(] which generates the list
  2466     [i,i+1,...,j-1], i.e. the upper bound is excluded. To include the upper
  2467     bound write [i..j], which is a shorthand for [i..j+1(].
  2468   - new lexicographic orderings and corresponding wellfoundedness theorems.
  2469 
  2470 * HOL/Arith:
  2471   - removed 'pred' (predecessor) function;
  2472   - generalized some theorems about n-1;
  2473   - many new laws about "div" and "mod";
  2474   - new laws about greatest common divisors (see theory ex/Primes);
  2475 
  2476 * HOL/Relation: renamed the relational operator r^-1 "converse"
  2477 instead of "inverse";
  2478 
  2479 * HOL/Induct/Multiset: a theory of multisets, including the wellfoundedness
  2480   of the multiset ordering;
  2481 
  2482 * directory HOL/Real: a construction of the reals using Dedekind cuts
  2483   (not included by default);
  2484 
  2485 * directory HOL/UNITY: Chandy and Misra's UNITY formalism;
  2486 
  2487 * directory HOL/Hoare: a new version of Hoare logic which permits many-sorted
  2488   programs, i.e. different program variables may have different types.
  2489 
  2490 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2491   [previously, this check worked only if the rewrite rule was unconditional]
  2492   Now rew can involve either definitions or equalities (either == or =).
  2493 
  2494 
  2495 *** ZF ***
  2496 
  2497 * theory Main includes everything; INCOMPATIBILITY: theory ZF.thy contains
  2498   only the theorems proved on ZF.ML;
  2499 
  2500 * ZF INCOMPATIBILITY: rule `equals0D' is now a well-formed destruct rule;
  2501   It and 'sym RS equals0D' are now in the default  claset, giving automatic
  2502   disjointness reasoning but breaking a few old proofs.
  2503 
  2504 * ZF/Update: new theory of function updates
  2505     with default rewrite rule  f(x:=y) ` z = if(z=x, y, f`z)
  2506   may also be iterated as in f(a:=b,c:=d,...);
  2507 
  2508 * in  let x=t in u(x), neither t nor u(x) has to be an FOL term.
  2509 
  2510 * calling (stac rew i) now fails if "rew" has no effect on the goal
  2511   [previously, this check worked only if the rewrite rule was unconditional]
  2512   Now rew can involve either definitions or equalities (either == or =).
  2513 
  2514 * case_tac provided for compatibility with HOL
  2515     (like the old excluded_middle_tac, but with subgoals swapped)
  2516 
  2517 
  2518 *** Internal programming interfaces ***
  2519 
  2520 * Pure: several new basic modules made available for general use, see
  2521 also src/Pure/README;
  2522 
  2523 * improved the theory data mechanism to support encapsulation (data
  2524 kind name replaced by private Object.kind, acting as authorization
  2525 key); new type-safe user interface via functor TheoryDataFun; generic
  2526 print_data function becomes basically useless;
  2527 
  2528 * removed global_names compatibility flag -- all theory declarations
  2529 are qualified by default;
  2530 
  2531 * module Pure/Syntax now offers quote / antiquote translation
  2532 functions (useful for Hoare logic etc. with implicit dependencies);
  2533 see HOL/ex/Antiquote for an example use;
  2534 
  2535 * Simplifier now offers conversions (asm_)(full_)rewrite: simpset ->
  2536 cterm -> thm;
  2537 
  2538 * new tactical CHANGED_GOAL for checking that a tactic modifies a
  2539 subgoal;
  2540 
  2541 * Display.print_goals function moved to Locale.print_goals;
  2542 
  2543 * standard print function for goals supports current_goals_markers
  2544 variable for marking begin of proof, end of proof, start of goal; the
  2545 default is ("", "", ""); setting current_goals_markers := ("<proof>",
  2546 "</proof>", "<goal>") causes SGML like tagged proof state printing,
  2547 for example;
  2548 
  2549 
  2550 
  2551 New in Isabelle98 (January 1998)
  2552 --------------------------------
  2553 
  2554 *** Overview of INCOMPATIBILITIES (see below for more details) ***
  2555 
  2556 * changed lexical syntax of terms / types: dots made part of long
  2557 identifiers, e.g. "%x.x" no longer possible, should be "%x. x";
  2558 
  2559 * simpset (and claset) reference variable replaced by functions
  2560 simpset / simpset_ref;
  2561 
  2562 * no longer supports theory aliases (via merge) and non-trivial
  2563 implicit merge of thms' signatures;
  2564 
  2565 * most internal names of constants changed due to qualified names;
  2566 
  2567 * changed Pure/Sequence interface (see Pure/seq.ML);
  2568 
  2569 
  2570 *** General Changes ***
  2571 
  2572 * hierachically structured name spaces (for consts, types, axms, thms
  2573 etc.); new lexical class 'longid' (e.g. Foo.bar.x) may render much of
  2574 old input syntactically incorrect (e.g. "%x.x"); COMPATIBILITY:
  2575 isatool fixdots ensures space after dots (e.g. "%x. x"); set
  2576 long_names for fully qualified output names; NOTE: ML programs
  2577 (special tactics, packages etc.) referring to internal names may have
  2578 to be adapted to cope with fully qualified names; in case of severe
  2579 backward campatibility problems try setting 'global_names' at compile
  2580 time to have enrything declared within a flat name space; one may also
  2581 fine tune name declarations in theories via the 'global' and 'local'
  2582 section;
  2583 
  2584 * reimplemented the implicit simpset and claset using the new anytype
  2585 data filed in signatures; references simpset:simpset ref etc. are
  2586 replaced by functions simpset:unit->simpset and
  2587 simpset_ref:unit->simpset ref; COMPATIBILITY: use isatool fixclasimp
  2588 to patch your ML files accordingly;
  2589 
  2590 * HTML output now includes theory graph data for display with Java
  2591 applet or isatool browser; data generated automatically via isatool
  2592 usedir (see -i option, ISABELLE_USEDIR_OPTIONS);
  2593 
  2594 * defs may now be conditional; improved rewrite_goals_tac to handle
  2595 conditional equations;
  2596 
  2597 * defs now admits additional type arguments, using TYPE('a) syntax;
  2598 
  2599 * theory aliases via merge (e.g. M=A+B+C) no longer supported, always
  2600 creates a new theory node; implicit merge of thms' signatures is
  2601 restricted to 'trivial' ones; COMPATIBILITY: one may have to use
  2602 transfer:theory->thm->thm in (rare) cases;
  2603 
  2604 * improved handling of draft signatures / theories; draft thms (and
  2605 ctyps, cterms) are automatically promoted to real ones;
  2606 
  2607 * slightly changed interfaces for oracles: admit many per theory, named
  2608 (e.g. oracle foo = mlfun), additional name argument for invoke_oracle;
  2609 
  2610 * print_goals: optional output of const types (set show_consts and
  2611 show_types);
  2612 
  2613 * improved output of warnings (###) and errors (***);
  2614 
  2615 * subgoal_tac displays a warning if the new subgoal has type variables;
  2616 
  2617 * removed old README and Makefiles;
  2618 
  2619 * replaced print_goals_ref hook by print_current_goals_fn and result_error_fn;
  2620 
  2621 * removed obsolete init_pps and init_database;
  2622 
  2623 * deleted the obsolete tactical STATE, which was declared by
  2624     fun STATE tacfun st = tacfun st st;
  2625 
  2626 * cd and use now support path variables, e.g. $ISABELLE_HOME, or ~
  2627 (which abbreviates $HOME);
  2628 
  2629 * changed Pure/Sequence interface (see Pure/seq.ML); COMPATIBILITY:
  2630 use isatool fixseq to adapt your ML programs (this works for fully
  2631 qualified references to the Sequence structure only!);
  2632 
  2633 * use_thy no longer requires writable current directory; it always
  2634 reloads .ML *and* .thy file, if either one is out of date;
  2635 
  2636 
  2637 *** Classical Reasoner ***
  2638 
  2639 * Clarify_tac, clarify_tac, clarify_step_tac, Clarify_step_tac: new
  2640 tactics that use classical reasoning to simplify a subgoal without
  2641 splitting it into several subgoals;
  2642 
  2643 * Safe_tac: like safe_tac but uses the default claset;
  2644 
  2645 
  2646 *** Simplifier ***
  2647 
  2648 * added simplification meta rules:
  2649     (asm_)(full_)simplify: simpset -> thm -> thm;
  2650 
  2651 * simplifier.ML no longer part of Pure -- has to be loaded by object
  2652 logics (again);
  2653 
  2654 * added prems argument to simplification procedures;
  2655 
  2656 * HOL, FOL, ZF: added infix function `addsplits':
  2657   instead of `<simpset> setloop (split_tac <thms>)'
  2658   you can simply write `<simpset> addsplits <thms>'
  2659 
  2660 
  2661 *** Syntax ***
  2662 
  2663 * TYPE('a) syntax for type reflection terms;
  2664 
  2665 * no longer handles consts with name "" -- declare as 'syntax' instead;
  2666 
  2667 * pretty printer: changed order of mixfix annotation preference (again!);
  2668 
  2669 * Pure: fixed idt/idts vs. pttrn/pttrns syntactic categories;
  2670 
  2671 
  2672 *** HOL ***
  2673 
  2674 * HOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2675   with `addloop' of the simplifier to faciliate case splitting in premises.
  2676 
  2677 * HOL/TLA: Stephan Merz's formalization of Lamport's Temporal Logic of Actions;
  2678 
  2679 * HOL/Auth: new protocol proofs including some for the Internet
  2680   protocol TLS;
  2681 
  2682 * HOL/Map: new theory of `maps' a la VDM;
  2683 
  2684 * HOL/simplifier: simplification procedures nat_cancel_sums for
  2685 cancelling out common nat summands from =, <, <= (in)equalities, or
  2686 differences; simplification procedures nat_cancel_factor for
  2687 cancelling common factor from =, <, <= (in)equalities over natural
  2688 sums; nat_cancel contains both kinds of procedures, it is installed by
  2689 default in Arith.thy -- this COULD MAKE EXISTING PROOFS FAIL;
  2690 
  2691 * HOL/simplifier: terms of the form
  2692   `? x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x)'  (or t=x)
  2693   are rewritten to
  2694   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t)',
  2695   and those of the form
  2696   `! x. P1(x) & ... & Pn(x) & x=t & Q1(x) & ... Qn(x) --> R(x)'  (or t=x)
  2697   are rewritten to
  2698   `P1(t) & ... & Pn(t) & Q1(t) & ... Qn(t) --> R(t)',
  2699 
  2700 * HOL/datatype
  2701   Each datatype `t' now comes with a theorem `split_t_case' of the form
  2702 
  2703   P(t_case f1 ... fn x) =
  2704      ( (!y1 ... ym1. x = C1 y1 ... ym1 --> P(f1 y1 ... ym1)) &
  2705         ...
  2706        (!y1 ... ymn. x = Cn y1 ... ymn --> P(f1 y1 ... ymn))
  2707      )
  2708 
  2709   and a theorem `split_t_case_asm' of the form
  2710 
  2711   P(t_case f1 ... fn x) =
  2712     ~( (? y1 ... ym1. x = C1 y1 ... ym1 & ~P(f1 y1 ... ym1)) |
  2713         ...
  2714        (? y1 ... ymn. x = Cn y1 ... ymn & ~P(f1 y1 ... ymn))
  2715      )
  2716   which can be added to a simpset via `addsplits'. The existing theorems
  2717   expand_list_case and expand_option_case have been renamed to
  2718   split_list_case and split_option_case.
  2719 
  2720 * HOL/Arithmetic:
  2721   - `pred n' is automatically converted to `n-1'.
  2722     Users are strongly encouraged not to use `pred' any longer,
  2723     because it will disappear altogether at some point.
  2724   - Users are strongly encouraged to write "0 < n" rather than
  2725     "n ~= 0". Theorems and proof tools have been modified towards this
  2726     `standard'.
  2727 
  2728 * HOL/Lists:
  2729   the function "set_of_list" has been renamed "set" (and its theorems too);
  2730   the function "nth" now takes its arguments in the reverse order and
  2731   has acquired the infix notation "!" as in "xs!n".
  2732 
  2733 * HOL/Set: UNIV is now a constant and is no longer translated to Compl{};
  2734 
  2735 * HOL/Set: The operator (UN x.B x) now abbreviates (UN x:UNIV. B x) and its
  2736   specialist theorems (like UN1_I) are gone.  Similarly for (INT x.B x);
  2737 
  2738 * HOL/record: extensible records with schematic structural subtyping
  2739 (single inheritance); EXPERIMENTAL version demonstrating the encoding,
  2740 still lacks various theorems and concrete record syntax;
  2741 
  2742 
  2743 *** HOLCF ***
  2744 
  2745 * removed "axioms" and "generated by" sections;
  2746 
  2747 * replaced "ops" section by extended "consts" section, which is capable of
  2748   handling the continuous function space "->" directly;
  2749 
  2750 * domain package:
  2751   . proves theorems immediately and stores them in the theory,
  2752   . creates hierachical name space,
  2753   . now uses normal mixfix annotations (instead of cinfix...),
  2754   . minor changes to some names and values (for consistency),
  2755   . e.g. cases -> casedist, dists_eq -> dist_eqs, [take_lemma] -> take_lemmas,
  2756   . separator between mutual domain defs: changed "," to "and",
  2757   . improved handling of sort constraints;  now they have to
  2758     appear on the left-hand side of the equations only;
  2759 
  2760 * fixed LAM <x,y,zs>.b syntax;
  2761 
  2762 * added extended adm_tac to simplifier in HOLCF -- can now discharge
  2763 adm (%x. P (t x)), where P is chainfinite and t continuous;
  2764 
  2765 
  2766 *** FOL and ZF ***
  2767 
  2768 * FOL: there is a new splitter `split_asm_tac' that can be used e.g.
  2769   with `addloop' of the simplifier to faciliate case splitting in premises.
  2770 
  2771 * qed_spec_mp, qed_goal_spec_mp, qed_goalw_spec_mp are available, as
  2772 in HOL, they strip ALL and --> from proved theorems;
  2773 
  2774 
  2775 
  2776 New in Isabelle94-8 (May 1997)
  2777 ------------------------------
  2778 
  2779 *** General Changes ***
  2780 
  2781 * new utilities to build / run / maintain Isabelle etc. (in parts
  2782 still somewhat experimental); old Makefiles etc. still functional;
  2783 
  2784 * new 'Isabelle System Manual';
  2785 
  2786 * INSTALL text, together with ./configure and ./build scripts;
  2787 
  2788 * reimplemented type inference for greater efficiency, better error
  2789 messages and clean internal interface;
  2790 
  2791 * prlim command for dealing with lots of subgoals (an easier way of
  2792 setting goals_limit);
  2793 
  2794 
  2795 *** Syntax ***
  2796 
  2797 * supports alternative (named) syntax tables (parser and pretty
  2798 printer); internal interface is provided by add_modesyntax(_i);
  2799 
  2800 * Pure, FOL, ZF, HOL, HOLCF now support symbolic input and output; to
  2801 be used in conjunction with the Isabelle symbol font; uses the
  2802 "symbols" syntax table;
  2803 
  2804 * added token_translation interface (may translate name tokens in
  2805 arbitrary ways, dependent on their type (free, bound, tfree, ...) and
  2806 the current print_mode); IMPORTANT: user print translation functions
  2807 are responsible for marking newly introduced bounds
  2808 (Syntax.mark_boundT);
  2809 
  2810 * token translations for modes "xterm" and "xterm_color" that display
  2811 names in bold, underline etc. or colors (which requires a color
  2812 version of xterm);
  2813 
  2814 * infixes may now be declared with names independent of their syntax;
  2815 
  2816 * added typed_print_translation (like print_translation, but may
  2817 access type of constant);
  2818 
  2819 
  2820 *** Classical Reasoner ***
  2821 
  2822 Blast_tac: a new tactic!  It is often more powerful than fast_tac, but has
  2823 some limitations.  Blast_tac...
  2824   + ignores addss, addbefore, addafter; this restriction is intrinsic
  2825   + ignores elimination rules that don't have the correct format
  2826         (the conclusion MUST be a formula variable)
  2827   + ignores types, which can make HOL proofs fail
  2828   + rules must not require higher-order unification, e.g. apply_type in ZF
  2829     [message "Function Var's argument not a bound variable" relates to this]
  2830   + its proof strategy is more general but can actually be slower
  2831 
  2832 * substitution with equality assumptions no longer permutes other
  2833 assumptions;
  2834 
  2835 * minor changes in semantics of addafter (now called addaltern); renamed
  2836 setwrapper to setWrapper and compwrapper to compWrapper; added safe wrapper
  2837 (and access functions for it);
  2838 
  2839 * improved combination of classical reasoner and simplifier:
  2840   + functions for handling clasimpsets
  2841   + improvement of addss: now the simplifier is called _after_ the
  2842     safe steps.
  2843   + safe variant of addss called addSss: uses safe simplifications
  2844     _during_ the safe steps. It is more complete as it allows multiple
  2845     instantiations of unknowns (e.g. with slow_tac).
  2846 
  2847 *** Simplifier ***
  2848 
  2849 * added interface for simplification procedures (functions that
  2850 produce *proven* rewrite rules on the fly, depending on current
  2851 redex);
  2852 
  2853 * ordering on terms as parameter (used for ordered rewriting);
  2854 
  2855 * new functions delcongs, deleqcongs, and Delcongs. richer rep_ss;
  2856 
  2857 * the solver is now split into a safe and an unsafe part.
  2858 This should be invisible for the normal user, except that the
  2859 functions setsolver and addsolver have been renamed to setSolver and
  2860 addSolver; added safe_asm_full_simp_tac;
  2861 
  2862 
  2863 *** HOL ***
  2864 
  2865 * a generic induction tactic `induct_tac' which works for all datatypes and
  2866 also for type `nat';
  2867 
  2868 * a generic case distinction tactic `exhaust_tac' which works for all
  2869 datatypes and also for type `nat';
  2870 
  2871 * each datatype comes with a function `size';
  2872 
  2873 * patterns in case expressions allow tuple patterns as arguments to
  2874 constructors, for example `case x of [] => ... | (x,y,z)#ps => ...';
  2875 
  2876 * primrec now also works with type nat;
  2877 
  2878 * recdef: a new declaration form, allows general recursive functions to be
  2879 defined in theory files.  See HOL/ex/Fib, HOL/ex/Primes, HOL/Subst/Unify.
  2880 
  2881 * the constant for negation has been renamed from "not" to "Not" to
  2882 harmonize with FOL, ZF, LK, etc.;
  2883 
  2884 * HOL/ex/LFilter theory of a corecursive "filter" functional for
  2885 infinite lists;
  2886 
  2887 * HOL/Modelcheck demonstrates invocation of model checker oracle;
  2888 
  2889 * HOL/ex/Ring.thy declares cring_simp, which solves equational
  2890 problems in commutative rings, using axiomatic type classes for + and *;
  2891 
  2892 * more examples in HOL/MiniML and HOL/Auth;
  2893 
  2894 * more default rewrite rules for quantifiers, union/intersection;
  2895 
  2896 * a new constant `arbitrary == @x.False';
  2897 
  2898 * HOLCF/IOA replaces old HOL/IOA;
  2899 
  2900 * HOLCF changes: derived all rules and arities
  2901   + axiomatic type classes instead of classes
  2902   + typedef instead of faking type definitions
  2903   + eliminated the internal constants less_fun, less_cfun, UU_fun, UU_cfun etc.
  2904   + new axclasses cpo, chfin, flat with flat < chfin < pcpo < cpo < po
  2905   + eliminated the types void, one, tr
  2906   + use unit lift and bool lift (with translations) instead of one and tr
  2907   + eliminated blift from Lift3.thy (use Def instead of blift)
  2908   all eliminated rules are derived as theorems --> no visible changes ;
  2909 
  2910 
  2911 *** ZF ***
  2912 
  2913 * ZF now has Fast_tac, Simp_tac and Auto_tac.  Union_iff is a now a default
  2914 rewrite rule; this may affect some proofs.  eq_cs is gone but can be put back
  2915 as ZF_cs addSIs [equalityI];
  2916 
  2917 
  2918 
  2919 New in Isabelle94-7 (November 96)
  2920 ---------------------------------
  2921 
  2922 * allowing negative levels (as offsets) in prlev and choplev;
  2923 
  2924 * super-linear speedup for large simplifications;
  2925 
  2926 * FOL, ZF and HOL now use miniscoping: rewriting pushes
  2927 quantifications in as far as possible (COULD MAKE EXISTING PROOFS
  2928 FAIL); can suppress it using the command Delsimps (ex_simps @
  2929 all_simps); De Morgan laws are also now included, by default;
  2930 
  2931 * improved printing of ==>  :  ~:
  2932 
  2933 * new object-logic "Sequents" adds linear logic, while replacing LK
  2934 and Modal (thanks to Sara Kalvala);
  2935 
  2936 * HOL/Auth: correctness proofs for authentication protocols;
  2937 
  2938 * HOL: new auto_tac combines rewriting and classical reasoning (many
  2939 examples on HOL/Auth);
  2940 
  2941 * HOL: new command AddIffs for declaring theorems of the form P=Q to
  2942 the rewriter and classical reasoner simultaneously;
  2943 
  2944 * function uresult no longer returns theorems in "standard" format;
  2945 regain previous version by: val uresult = standard o uresult;
  2946 
  2947 
  2948 
  2949 New in Isabelle94-6
  2950 -------------------
  2951 
  2952 * oracles -- these establish an interface between Isabelle and trusted
  2953 external reasoners, which may deliver results as theorems;
  2954 
  2955 * proof objects (in particular record all uses of oracles);
  2956 
  2957 * Simp_tac, Fast_tac, etc. that refer to implicit simpset / claset;
  2958 
  2959 * "constdefs" section in theory files;
  2960 
  2961 * "primrec" section (HOL) no longer requires names;
  2962 
  2963 * internal type "tactic" now simply "thm -> thm Sequence.seq";
  2964 
  2965 
  2966 
  2967 New in Isabelle94-5
  2968 -------------------
  2969 
  2970 * reduced space requirements;
  2971 
  2972 * automatic HTML generation from theories;
  2973 
  2974 * theory files no longer require "..." (quotes) around most types;
  2975 
  2976 * new examples, including two proofs of the Church-Rosser theorem;
  2977 
  2978 * non-curried (1994) version of HOL is no longer distributed;
  2979 
  2980 
  2981 
  2982 New in Isabelle94-4
  2983 -------------------
  2984 
  2985 * greatly reduced space requirements;
  2986 
  2987 * theory files (.thy) no longer require \...\ escapes at line breaks;
  2988 
  2989 * searchable theorem database (see the section "Retrieving theorems" on
  2990 page 8 of the Reference Manual);
  2991 
  2992 * new examples, including Grabczewski's monumental case study of the
  2993 Axiom of Choice;
  2994 
  2995 * The previous version of HOL renamed to Old_HOL;
  2996 
  2997 * The new version of HOL (previously called CHOL) uses a curried syntax
  2998 for functions.  Application looks like f a b instead of f(a,b);
  2999 
  3000 * Mutually recursive inductive definitions finally work in HOL;
  3001 
  3002 * In ZF, pattern-matching on tuples is now available in all abstractions and
  3003 translates to the operator "split";
  3004 
  3005 
  3006 
  3007 New in Isabelle94-3
  3008 -------------------
  3009 
  3010 * new infix operator, addss, allowing the classical reasoner to
  3011 perform simplification at each step of its search.  Example:
  3012         fast_tac (cs addss ss)
  3013 
  3014 * a new logic, CHOL, the same as HOL, but with a curried syntax
  3015 for functions.  Application looks like f a b instead of f(a,b).  Also pairs
  3016 look like (a,b) instead of <a,b>;
  3017 
  3018 * PLEASE NOTE: CHOL will eventually replace HOL!
  3019 
  3020 * In CHOL, pattern-matching on tuples is now available in all abstractions.
  3021 It translates to the operator "split".  A new theory of integers is available;
  3022 
  3023 * In ZF, integer numerals now denote two's-complement binary integers.
  3024 Arithmetic operations can be performed by rewriting.  See ZF/ex/Bin.ML;
  3025 
  3026 * Many new examples: I/O automata, Church-Rosser theorem, equivalents
  3027 of the Axiom of Choice;
  3028 
  3029 
  3030 
  3031 New in Isabelle94-2
  3032 -------------------
  3033 
  3034 * Significantly faster resolution;
  3035 
  3036 * the different sections in a .thy file can now be mixed and repeated
  3037 freely;
  3038 
  3039 * Database of theorems for FOL, HOL and ZF.  New
  3040 commands including qed, qed_goal and bind_thm store theorems in the database.
  3041 
  3042 * Simple database queries: return a named theorem (get_thm) or all theorems of
  3043 a given theory (thms_of), or find out what theory a theorem was proved in
  3044 (theory_of_thm);
  3045 
  3046 * Bugs fixed in the inductive definition and datatype packages;
  3047 
  3048 * The classical reasoner provides deepen_tac and depth_tac, making FOL_dup_cs
  3049 and HOL_dup_cs obsolete;
  3050 
  3051 * Syntactic ambiguities caused by the new treatment of syntax in Isabelle94-1
  3052 have been removed;
  3053 
  3054 * Simpler definition of function space in ZF;
  3055 
  3056 * new results about cardinal and ordinal arithmetic in ZF;
  3057 
  3058 * 'subtype' facility in HOL for introducing new types as subsets of existing
  3059 types;
  3060 
  3061 
  3062 $Id$