Could owl:sameAs reference non-OWL resources?

Somehow a follow-up of my previous question about "things" ...

I'm currently trying to figure how OWL can interoperate with legacy in
other languages and formats, in particular DAML libraries, Topic Maps
Published Subject Indicators, and in general any format using URIs to
name-define "things" (or RDF resources, or Topic Maps subjects). Could be
as well plain on-line HTML thesaurus or glossary, Dewey Classes, LoC
Subject Headings ...

Seems to me that one important aim of OWL (the main one?) should be to use
those URIs to achieve the "colocation objective", which is also the main
objective of Topic Maps and Published Subjects.

The colocation objective in the distributed Web environment means being
able to assert that two "things" are identical. owl:sameAs allows to
achieve that it seems. But what is not clear to me is if the URI referenced
by owl:sameAs has to define an OWL resource, or if it could be another kind
of resource.

In the example given in

<owl:Class rdf:ID="FootballTeam">
  <owl:sameAs rdf:resource=""/>

Is "" supposed to reference an OWL element?
What if it reference a DAML legacy for instance?
Or an XTM topic element? Should it be converted into OWL before being used
that way? IOW, will owl:sameAs ensure backward compatibility with DAML+OIL
libraries? Or support XTM subject indicators? Or UDDI, XRI ... whatever.

Otherwise said, will one be able to use owl:sameAs with the same
flexibility as XTM <subjectIndicatorRef> which has basically the same
semantics? The above example would read in XTM :

<topic id="FootballTeam">
		<subjectIndicatorRef xlink:href=""/>

<subjectIndicatorRef> does not assume any particular format for the
resource at "". Could be an XML fragment,
could be HTML, could be OWL or any other relevant syntax. The
recommendation on Published Subjects somehow give clues on what kind of
resource should be used that way. BTW this recommendation is currently in
the same final draft status than OWL. See

Bottom line: OWL elements can be used as Published Subject Indicators,
provided the OWL ontology contains some specific information (like
publisher identity, human-readable definitions ...) that can be expressed
in OWL. So OWL should be IMO (the most) recommended format for Published
Subject Indicators. Please note that so far it's only a personal view, that
I will try to push of course on the table of Published Subjects TC ASAP
(next week).
But to achieve the round trip, it would be cool if through owl:sameAs, one
could reference a Published Subject Indicator using e.g. XTM syntax. Being
able to ensure that round trip would be IMO a giant step towards semantic

Feedback much welcome.

Bernard Vatant
Senior Consultant
Knowledge Engineering
Mondeca -

Received on Monday, 28 April 2003 06:14:30 UTC