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RDF and OWL compatibility

From: Michael Sintek <sintek@dfki.uni-kl.de>
Date: Tue, 03 Jan 2006 09:53:25 +0100
Message-ID: <43BA3B85.2020408@dfki.uni-kl.de>
To: public-rif-wg@w3.org
CC: sintek@dfki.uni-kl.de

Happy New Year!

To stimulate some discussion on RDF and OWL
compatibility (which, I assume, should take
place on the mailing list and not in the wiki),
here a first question:

"Will RIF prescribe how to map RDF/OWL ontologies/knowledge
bases to Horn logic, or will RIF just define
a general rule language for which several
mappings are supported?"

E.g., the straightforward mapping of RDF triples
<s,p,o> to Horn facts p(s,o), as mentioned
on http://www.w3.org/2005/rules/wg/wiki/RDF_Compatibility
at the beginning, would break "plain" RDF
compatibility as simple queries which are supported
by most (all?) RDF APIs and query langauages
will not work: query patterns of the form
<s,?p,o> (i.e., where at least the predicate
is a variable) cannot be mapped to first order
queries (and thus not to Horn logic).

For applications in need of plain RDF support,
a much simpler mapping can be used, e.g., with
the well-known "true" predicate: true(s,p,o), or, if
named graphs are also to be supported,
true(s,p,o,g) or true(triple(s,p,o),g)
(the latter form has been used in the
Semantic Web rule language TRIPLE [1], where
this mapping also covered substantial parts of
RDFS semantics).

For compatibility with OWL (where OWL Lite/DL and
OWL Full will most likely have to be handled in different
ways), and depending on the kind of rules/inferences one
wishes to support, several other mappings come into
play.

[1] http://triple.semanticweb.org/

Michael

-- 
Michael Sintek -- DFKI GmbH, Kaiserslautern
http://www.michael-sintek.de -- sintek@dfki.uni-kl.de
phone: +49 631 205-3460 -- fax: +49 631 205-4910
Received on Tuesday, 3 January 2006 08:53:45 GMT

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