- From: Antoine Isaac <aisaac@few.vu.nl>
- Date: Thu, 5 Jan 2012 17:59:14 +0100
- To: <public-esw-thes@w3.org>
>> Well, nothing prevents you from doing that, but then you have lost some information. Despite the property names, asserting a skos:broader is indeed *more precise* than asserting a skos:broaderTransitive. Because the former implies the latter (mathematically speaking, the skos:broaderTransitive is the transitive closure of the skos:broader relation, http://en.wikipedia.org/wiki/Transitive_closure) > > So as I understand it, broader/narrower is a safe basis for everyone, and then one could augment the detail level with transitive statements. > It's not explicit in the SKOS primer, I understood that I could use transitive relations instead of B/N to express a hierarchical tree where all relations are transitive (animals> mammals> cats, all cats are animals) Not exactly. You assert the skos:broader that you have in your original thesaurus, and then the semantics of SKOS would allow an OWL reasoner to automatically infer the skos:broaderTransitive you can then use to access the "transitive hierarchy". You don't need to use broaderTransitive to "express" a tree, you use it to "read the information" from that tree. If you load *only* the skos:broader of http://www.w3.org/TR/skos-primer/#sectransitivebroader in an RDFS reasoner, and then you fire a query ?x skos:broaderTransitive ex:animals then you will find ex:cats and ex:mammals in your results. > I saw another example recently of this "all-transitive hierarchical tree" [1], the author also seems to model its vocabulary only based on transitive relations [2] > > >> Well, the optimal scenario is that you would assert your skos:broader "individual steps in the hierarchy" first: >> ex:ConceptA skos:broader ex:ConceptB >> ex:ConceptB skos:broader ex:ConceptC >> >> And then your thesaurus app could create and maintain the transitive relation: >> ex:ConceptA skos:broaderTransitive ex:ConceptB >> ex:ConceptB skos:broaderTransitive ex:ConceptC >> ex:ConceptA skos:broaderTransitive ex:ConceptC > > ok, the app could detect some multi-steps relations and create transitive links when they exists > but in your example, the two first statements are not really useful, are they ? which ones? > > My goal is to be able to do query expansion, looking for things linked to a concept, but also things linked to a skos:broader concept, and finally things linked to a skos:broaderTransitive concept That sounds like a correct usage scenario for broader/broaderTransitive, yes. Antoine > > > > > [1] http://156.35.31.156/pscs/page/naics/2012/resource/4529 > [2] http://156.35.31.156/web/en/softwate-and-datasets/datasets/38-pscs > > -- > Dominique Guardiola, QUINODE > • http://www.quinode.fr/ > • Tel : 04.27.86.84.37 > • Mob : 06.15.13.22.27 > > > > > >
Received on Thursday, 5 January 2012 16:54:48 UTC