- From: Richard Cyganiak <richard@cyganiak.de>
- Date: Fri, 20 Jul 2007 20:26:08 +0200
- To: Rinke Hoekstra <hoekstra@uva.nl>
- Cc: semantic-web@w3.org, Alexander Boer <aboer@uva.nl>, Thomas Gordon <thomas.gordon@fokus.fraunhofer.de>
Rinke, On 20 Jul 2007, at 12:36, Rinke Hoekstra wrote: > I have a question regarding the rdf:Statement mechanism for > reification: what is the semantics of an rdf:Statement consisting > of multiple subject, predicate and object properties? The RDF spec doesn't define any semantics at all for reification. Thus, in standard RDF, the example you've given below is just a bunch of meaningless triples. People who use RDF reification assign their own private, local meaning to the reification vocabulary. That's fine as long as you are in a closed system. Of course you have to be very careful when exchanging reified statements with other parties. (In other words: You probably shouldn't.) Regarding your example with multiple rdf:subject, rdf:predicate and rdf:object statements, all I can say is: Don't. Best, Richard > > As far as we can tell, the RDF spec. is silent on this issue, and > leaves implicit whether there is a 1:1 mapping between a triple and > its reification as a rdf:Statement. > > Supposing this 1:1 mapping holds, the following RDF should be > incorrect, or at least problematic: > > <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"> > <rdf:Statement rdf:ID="S1"> > <rdf:subject rdf:resource="http://www.leibnizcenter.org/ > information/people/rinke-hoekstra" /> > <rdf:subject rdf:resource="http://www.leibnizcenter.org/ > information/people/alexander-boer" /> > <rdf:predicate rdf:resource="http://description.org/schema/ > Creator"/> > <rdf:predicate rdf:resource="http://description.org/schema/ > Fish"/> > <rdf:object rdf:datatype= > "http://www.w3.org/2001/XMLSchema#string">Rinke Hoekstra > </rdf:object> > <rdf:object rdf:datatype= > "http://www.w3.org/2001/XMLSchema#string">Alexander Boer > </rdf:object> > </rdf:Statement> > </rdf:RDF> > > The above example implicitly states that http:// > www.leibnizcenter.org/information/people/rinke-hoekstra and http:// > www.leibnizcenter.org/information/people/alexander-boer, and http:// > description.org/schema/Creator and http://description.org/schema/ > Fish pairwise point to the same resource. This is fine. > > However, for datatype resources this is really problematic as the > above RDF states that the *strings* "Rinke Hoekstra" and "Alexander > Boer" are equal. Something which is clearly not true... > > The W3C RDF Validator validates the above RDF as being correct. Is > this intended? > > Thanks, > > Rinke Hoekstra > > -- > ---------------------------------------------- > Drs. Rinke Hoekstra > > Email: hoekstra@uva.nl Skype: rinkehoekstra > Phone: +31-20-5253499 Fax: +31-20-5253495 > Web: http://www.leibnizcenter.nl/users/rinke > > Leibniz Center for Law, Faculty of Law > University of Amsterdam, PO Box 1030 > 1000 BA Amsterdam, The Netherlands > ----------------------------------------------<hoekstra.vcf>
Received on Friday, 20 July 2007 18:26:44 UTC