[Bug 6044] New: Revise equality of dateTime values without timezone

http://www.w3.org/Bugs/Public/show_bug.cgi?id=6044

           Summary: Revise equality of dateTime values without timezone
           Product: XML Schema
           Version: 1.1 only
          Platform: Macintosh
               URL: http://lists.w3.org/Archives/Public/www-xml-schema-
                    comments/2008JulSep/0135.html
        OS/Version: Mac System 9.x
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Datatypes: XSD Part 2
        AssignedTo: cmsmcq@w3.org
        ReportedBy: cmsmcq@w3.org
         QAContact: www-xml-schema-comments@w3.org


In email to the XML Schema comments list on 5 September 2008
(http://lists.w3.org/Archives/Public/www-xml-schema-comments/2008JulSep/0135.html),
Peter F. Patel-Schneider raised the following issue (among others):

  1/ Time instants
  ...
  1.2/ Handling "time instants" without a timezone

  There are already OWL ontologies that contain dateTime values where
  the timezone is absent. Such dateTime values may come from different
  documents, and that really have a different notion of what their
  local (unspecified) time is. The LC draft [2], however, makes these
  values all equal, as they are identical.

  The OWL WG is proceeding along a path to require timezones in
  dateTime values, i.e., dateTime values without a timezone will be
  syntactically illegal. However, tools may attempt to recover, for
  example by using the local time zone for the data source, but if
  they do so, they SHOULD produce a warning. Since such recovery may
  produce incorrect results, it should be done with caution, and data
  providers would be strongly encouraged to provide timezone
  information for all dateTime values.

  Adding in missing timezone values appears to violate the equality of
  dateTime values from the LC draft, as dateTime values without
  timezone information that compare equal according to the LC draft
  can be turned into dateTime values that do not compare equal.

  The WG requests that dateTime values missing a timezone that are
  otherwise equal do not compare as equal. The WG requests that
  dateTime values missing a timezone be instead *independently*
  treated as if they had one of the possible timezone values.


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Received on Tuesday, 9 September 2008 02:07:02 UTC