- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Wed, 17 Apr 2002 18:33:35 -0500
- To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
- Cc: www-webont-wg@w3.org
> > >> I did my best at: >> >> http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Apr/0178.html >> > > >In light of the feedback, I have been clarifying my idea of what the problem >is. > >Problem statement: > >Layering on top of RDF involves using graph syntax to encode OWL concepts. >If such graph syntax is asserted then the RDF model theory assigns meaning >to such syntax specifically denoting things in the domain of discourse that >correspond to the syntactic expressions of OWL. Given this, an OWL model >theory with appropriate entailments (in which the theory of classes in OWL >is recognisable as a subtheory of some well known set theory) is difficult >and problematic to construct. > > >Solution statement: > >Using unasserted triples for the syntactic structures of OWL allows an OWL >interpretation to assign a meaning to a subgraph which need bear no >correspondence with the meaning of corresponding asserted triples in RDF. > > > >Example: > >The RDF document: > ><rdf:Description rdf:about="#John"> > <rdf:type rdf:resource="#Student"> > <rdf:type rdf:resource="#Employee"> ></rdf:Description> > >understood with rdf:type denoting set membership, would, under almost all >set theories, entail #John being a member of the intersection of #Student >and #Employee. >In daml+oil this is said: > ><rdf:Description rdf:about="#John"> > <rdf:type> > <daml:class> > <daml:intersectionOf rdf:parseType="daml:collection"> > <daml:class rdf:ID="Employee"/> > <daml:class rdf:ID="Student"/> > <daml:intersectionOf> > </daml:class> > </rdf:type> ></rdf:Description> > >If we leave the daml class expression: > > ><rdf:RDF> > <daml:class> > <daml:intersectionOf rdf:parseType="daml:collection"> > <daml:class rdf:ID="Employee"/> > <daml:class rdf:ID="Student"/> > <daml:intersectionOf> > </daml:class> ></rdf:RDF> > >as unasserted then OWL can assign a meaning to this expression wholly >independently of RDF. > > >Have I got it? That seems a fair summary to me, yes. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Wednesday, 17 April 2002 19:33:39 UTC