- From: Dan Brickley <danbri@w3.org>
- Date: Wed, 4 Aug 2004 12:09:20 -0400
- To: "Miles, AJ (Alistair) " <A.J.Miles@rl.ac.uk>
- Cc: "'Supekar, Kaustubh S.'" <Supekar.Kaustubh@mayo.edu>, "'public-esw-thes@w3.org'" <public-esw-thes@w3.org>
* Miles, AJ (Alistair) <A.J.Miles@rl.ac.uk> [2004-08-04 16:49+0100] > > OK here goes at the compelling argument ... > > So you've got a concept A and two concept schemes X and Y. > > Concept A is in scheme X and also in scheme Y. > > Concept A is a top concept in scheme X, but not in scheme Y. > > Using the current version of SKOS Core this is written as (assuming standard > namespaces) ... > > <rdf:RDF> > > <skos:TopConcept rdf:about="http://example.org#A"> > <skos:inScheme rdf:resource="http://example.org#X"/> > <skos:inScheme rdf:resource="http://example.org#Y"/> > </skos:TopConcept> > > </rdf:RDF> > > So now a program wants to identify all the top concepts from scheme Y, and > applies the query ... > > SELECT ?x > WHERE > (?x rdf:type skos:TopConcept) (?x skos:inScheme http://example.org#Y) > > ... and will get back concept A included in the result set, which is > incorrect. > > I.e. the true semantics of the top concept idea are not properly expressed > in the current SKOS Core vocab. We need to be able to express unambiguously > which scheme a concept is a top concept in. > > Hence the proposal for a skos:hasTopConcept property. > > So under the new proposal, the above scenario would expressed as follows ... > > <rdf:RDF> > > <skos:Concept rdf:about="http://example.org#A"> > <skos:inScheme rdf:resource="http://example.org#X"/> > <skos:inScheme rdf:resource="http://example.org#Y"/> > </skos:Concept> > > <skos:ConceptScheme rdf:about="http://example.org#X"> > <skos:hasTopConcept rdf:resource="http://example.org#A"/> > </skos:ConceptScheme> > > <skos:ConceptScheme rdf:about="http://example.org#Y"> > </skos:ConceptScheme> > > </rdf:RDF> > > This removes the ambiguity. > > Am I getting there yet? > Thanks, this identifies a discomfort I've had w/ interactions between 'top concept' notion and thesaurus mixing. At heart you're saying 'top concept' is a relation between a a scheme/dataset/thesaurus and a concept. Makes sense to me. So would this be: <owl:FunctionalProperty rdf:about="http:///....../skos/core#hasTopConcept"/> ie. anything that has a skos:hasTopConcept has only one such thing? Dan
Received on Wednesday, 4 August 2004 12:10:07 UTC