Re: SKOS transitive hierarchical relations

>> 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)
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> 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]
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>> 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
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>> 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
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> 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?


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> 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
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> [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
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> --
> Dominique Guardiola, QUINODE
> • http://www.quinode.fr/
> • Tel : 04.27.86.84.37
> • Mob : 06.15.13.22.27
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Received on Thursday, 5 January 2012 16:54:48 UTC