On Montag, 7. Juli 2008, Jeff Thompson wrote: > Markus Krötzsch wrote: > > Also, SMW can *export* your queries now: click on the "RDF feed" link on > > a concept page to see the machine-readable version of the query. The OWL > > format that we use for export can nicely capture many SMW queries, and > > OWL tools can actually read these descriptions and reuse them externally. > > So SMW now cannot just export your wiki data, but also conceptual > > information about your topic. > > The SMW query is: > [[Category:Event]] [[Start date::> Jan 1 2008]] [[Start date::< Dec 31 > 2008]] > > Here is the OWL class description of the query. I don't see how it limits > the range of dates. Does OWL have support for class restrictions on > greater than/less than on literals?
No, this is not supported by OWL. Accordingly, the export uses subClassOf in such cases (the exported OWL description is a superclass of the SWM concept). If the OWL translation can be done in an exact way, the SMW concept is defined to be equivalent in the export. In the OWL working group, we are currently considering the inclusion of data ranges into OWL 2. The current proposal is to allow the use of certain XML-Schema datatype facets to create sub-datatypes. This would also allow for > and < on numbers. There is not much hope to achieve something similar for strings (SMW also can order by strings), since the order of strings depends on language settings and collation preferences that are not expressible in XML Schema. Also it remains to be seen which datatypes OWL 2 will eventually endorse. Regards, Markus > > <owl:Class > rdf:about="http://semanticweb.org/id/Concept-3ASemantic_Web_events_2008";> > <rdfs:label>Semantic Web events 2008</rdfs:label> > <swivt:page > rdf:resource="http://semanticweb.org/wiki/Concept:Semantic_Web_events_2008"; >/> <rdfs:isDefinedBy > rdf:resource="http://semanticweb.org/wiki/Special:ExportRDF/Concept:Semanti >c_Web_events_2008"/> <rdfs:subClassOf> > <owl:Class> > <owl:intersectionOf rdf:parseType="Collection"> > <owl:Class > rdf:about="http://semanticweb.org/id/Category-3AEvent"/> <owl:Restriction> > <owl:onProperty > rdf:resource="http://semanticweb.org/id/Property-3AStart_date"/> > <owl:someValuesFrom > rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/> > </owl:Restriction> > <owl:Restriction> > <owl:onProperty > rdf:resource="http://semanticweb.org/id/Property-3AStart_date"/> > <owl:someValuesFrom > rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/> > </owl:Restriction> > </owl:intersectionOf> > </owl:Class> > </rdfs:subClassOf> > </owl:Class> -- Markus Krötzsch Semantic MediaWiki http://semantic-mediawiki.org http://korrekt.org [EMAIL PROTECTED]
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